JP2009299014A - Polymer film, phase difference film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

[Problem] There is no smoke, oil contamination or foreign matter failure in the manufacturing process, and it is possible to increase the stripping and drying speed without reducing the casting speed in the manufacturing process. A polymer film obtained by operation is provided.
A polymer film comprising a polymer and a high molecular weight plasticizer, the high molecular weight plasticizer comprising:
At least an aliphatic high molecular weight plasticizer (PA) which is a polycondensate obtained using an aliphatic dicarboxylic acid and an aliphatic diol as raw materials and has a number average molecular weight of 700 to 10,000,
A polycondensate obtained by using at least one of an aliphatic diol and a diol having at least one aromatic ring and a dicarboxylic acid having at least one aromatic ring as raw materials, and having a number average molecular weight of 700 to 10,000 An aromatic high molecular weight plasticizer (PB);
A total content of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 2 to 30% by mass with respect to the polymer, and the fat A polymer film having a mass ratio of the aromatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) of 1/9 to 9/1.
[Selection figure] None

Description

  The present invention relates to a polymer film, a retardation film, a polarizing plate, and a liquid crystal display device. More specifically, it does not cause smoke or oil contamination during manufacturing, has excellent surface shape, has excellent edge cutting, roll dirt, dimensions, polarizing plate durability and film durability, and easily develops optical properties. It relates to a polymer film that can be controlled. Furthermore, the present invention also relates to a cellulose ester film suitable as the polymer and a retardation film, a polarizing plate and a liquid crystal display device using the same.

  Polymer films represented by cellulose ester, polyester, polycarbonate, cycloolefin polymer, vinyl polymer, polyimide and the like are used for silver halide photographic light-sensitive materials, retardation films, polarizing plates and image display devices. From these polymers, films that are more excellent in terms of flatness and uniformity can be produced, and are therefore widely used as films for optical applications. For example, a cellulose ester film having appropriate moisture permeability can be directly bonded on-line with the most common polarizing film made of polyvinyl alcohol (PVA) / iodine. For this reason, cellulose esters, particularly cellulose acetate, are widely used as protective films for polarizing plates.

  When the transparent polymer film is used for optical applications such as a retardation film, a retardation film support, a polarizing plate protective film, and a liquid crystal display device, the control of the optical anisotropy depends on the performance of the display device ( For example, it is a very important factor in determining visibility. On the other hand, as a method for producing a transparent polymer film used for optical applications, a solution film-forming method having a good surface shape is used, but in recent years, a melt film-forming method is also used. In the case of the solution casting method, it is preferable to add a plasticizer for the purpose of imparting high-speed film-forming suitability during production. This is because by adding a plasticizer, the solvent can be volatilized in a short time during drying during solution casting, and the amount of residual solvent in the polymer film can be reduced.

  However, transparent polymer films containing commonly used plasticizers (eg, triphenyl phosphate, ethyl phthalyl ethyl glycolate, trimethylol propane tribenzoate, acetyl citrate tributyrate, etc.) are severe during the manufacturing process. Attempting to process under conditions may cause undesirable phenomena or adversely affect the film. For example, when a transparent polymer film is processed at a high temperature, smoke may be generated or it may be contaminated with oil. For this reason, the manufacturing conditions and the processing conditions for the transparent polymer film using a plasticizer are naturally limited. On the other hand, it is known to use a high molecular weight plasticizer for a photographic triacetyl cellulose ester film, but it is difficult to imagine that the material can be applied to optical applications after being treated at high temperature. The characteristics to be possessed by the material were unknown (for example, see Patent Document 1).

  Further, in a photographic film, a cellulose ester support obtained by adding a photographic emulsion to a cellulose ester support containing a dibasic acid-glycol (1-8 unit) linear ester plasticizer sealed with a monobasic acid. The photographic film is disclosed, and it is described that it is preferable for curling elimination (see, for example, Patent Document 2). There is no problem in applying this form to optical applications, but its anisotropic properties are insufficient to apply it to desired optical characteristics, particularly high retardation plates, and in production as a film for optical applications. No description of preferred embodiments is found. On the other hand, among the polyesters composed of polyethylene glycol and aliphatic dibasic acid, a cellulose acetate molded article containing a polyester having an average molecular weight in the range of 700 to 4000 has been disclosed, and plasticizing effect, hardly volatile, antistatic properties are disclosed. (For example, refer to Patent Document 3). Even in this method, the anisotropy is insufficient to be applied to a retardation film as an optical application, and it is difficult to develop the liquid crystal display device for VA and OCB that require high optical anisotropy. there were.

  Next, a TAC film characterized by adding a methylene chloride-soluble polyurethane resin to TAC having an acetylation degree of 58% or more is described, which is effective for plasticizing effect, hardly volatile, and antistatic properties. There is a description (see, for example, Patent Document 4). However, the cellulose ester film mixed with polyurethane resin has a problem of yellowing when exposed to light for a long time, and is difficult to use for optical applications. Furthermore, the cellulose derivative resin composition characterized by containing a phthalic polyester is described as being a good plasticizer for a cellulose ester film (see, for example, Patent Document 5). However, the material has a large amount of aromatic group components, and when a cellulose ester film is produced, the solubility in an organic solvent is insufficient in the case of solution casting, or the phthalic polyester is applied to the film surface. It was difficult to bleed out and produce a good planar film.

  In addition, by using a semi-crystalline aliphatic-aromatic copolyester, cellulose ester and aliphatic polyester or aliphatic-aromatic copolyester suitable for molding into plastic products, fibers or films by molding or extrusion processing can be used. There is a description of the provision of the blend containing (refer patent document 6). Although these materials can be used for extrusion molding, an extruded film is inferior in terms of surface for optical applications, and it has been difficult to develop the technique for optical applications. On the other hand, a multi-branched polyester polymer is also disclosed, and a cellulose ester film that can achieve both hardness and brittleness resistance and is excellent in moisture resistance and durability (for example, see Patent Document 7) is effective. In order to obtain the effect, it was found that a large amount of addition was required, the surface condition was poor, and sufficient addition was difficult and the practicality was inferior.

  Further, a film is formed using a cellulose ester containing a polyester polyol obtained from a glycol having an average carbon number of 2 to 3.5 and an (anhydrous) dibasic acid having an average carbon number of 4 to 5.5. Then, in the cellulose ester film produced by stretching, an in-plane retardation value is 30 to 200 nm and a retardation value in the thickness direction is in the range of 70 to 400 nm. (For example, see Patent Document 8). However, since the technique is carried out at a high temperature when the cellulose ester film is stretched, it has been found that the material is volatilized and causes process contamination, which is difficult in practical use.

  Next, an aromatic terminal ester having a molecular weight of 300 or more and less than 1500 is described, the optical performance is stable and the humidity stability is high, and at the same time, there is no foreign matter failure due to generation of chips during film formation. A technique is disclosed in which a high cellulose film can be obtained, and a highly durable polarizing plate and liquid crystal display device can be obtained by using the cellulose ester film (see, for example, Patent Document 9). However, the material has a problem that it contains a large amount of low-boiling volatile components, and it has been found that the material is not suitable for practical use because it significantly contaminates the process when the cellulose ester film is formed. Further, it has a glass transition temperature of less than about 10 ° C. consisting of a specific dicarboxylic acid (aromatic dicarboxylic acid / aliphatic dicarboxylic acid / alicyclic dicarboxylic acid) and an aliphatic diol / polyalkylene ether / alicyclic diol. Although a copolyester composition has been disclosed (see, for example, Patent Document 10), even when the material is applied to the cellulose ester which is the polymer of the present invention, the compatibility with the cellulose ester is not improved and the bleedout is significantly reduced. It was bad.

  Also disclosed is a cellulose ester film comprising a cellulose ester and an ester plasticizer having a benzenecarboxylic acid or phenol residue at both ends and having an aliphatic cyclic glycol and an aliphatic cyclic dibasic acid. (For example, refer to Patent Document 11), there is a description of providing a cellulose ester film that is excellent in humidity fluctuation durability and does not physically deteriorate due to a decrease in film thickness (thinning). In this case, the compatibility with the cellulose ester was poor and bleed-out was easily generated, so that it was not applicable from the viewpoint of planarity. Furthermore, it is disclosed that an aromatic end-capped alkyl polyester is blended with a cellulose ester to provide a polymeric cellulose ester modifier that does not cause a decrease in transparency or cloudiness (see, for example, Patent Document 12). However, when producing a cellulose ester film, the compatibility with the cellulose ester is poor and bleed-out easily occurs, and it cannot be applied from a planar viewpoint.

  Further, it is disclosed that a specific plasticizer (aromatic ring-containing polyvalent carboxylic acid ester) is used in combination with polyester (for example, see Patent Document 13). According to this technique, there is a description that a retardation plate having excellent polarization degree durability and excellent light leakage prevention property can be obtained. Although these improvements are certainly seen, not only the improvement level due to the specific plasticizer combined effect was found to be small, but also the process contamination due to the volatility failure in the process of the specific plasticizer was remarkable, making it suitable for production. It was lacking.

  Also disclosed is a cellulose ester film obtained by polymerizing an ethylenically unsaturated monomer and containing a polymer having a weight average molecular weight of 500 or more and less than 10,000, and it is difficult for precipitates or volatiles to be generated from the web during production. And providing a high-quality polarizing plate that has a low moisture permeability, a very low elasticity even in a high temperature and high humidity environment, and does not deteriorate the polarizer even in a high temperature and high humidity condition (for example, Patent Document 14). reference). Certainly, although this material has improved properties, the solubility in cellulose ester is insufficient, and a large amount of addition is required to obtain an effective effect. It was difficult and inferior in practicality.

  Furthermore, there is a description of a polarizing plate protective film characterized by having a styrene / maleic anhydride copolymer and a cellulose ester, and a cellulose ester film that suppresses fluctuations in retardation values due to humidity fluctuations and does not cause contrast unevenness. The polarizing plate protective film used and its manufacturing method are disclosed, and it is described that it is possible to provide a polarizing plate and a liquid crystal display device with stable display quality using the polarizing plate protective film (for example, patents) Reference 15). However, since the raw material contains a reactive acid anhydride, the recoverability of the cellulose ester film is difficult, and there is a risk of changing the film quality and optical characteristics when stored for a long time. It was not suitable for practical use.

Japanese Patent Application Laid-Open No. 5-197073 US Pat. No. 3,054,673 Japanese Patent Publication No. 43-016305 Japanese Patent Publication No. 44-032672 JP-A 61-276836 US Pat. No. 5,559,171 JP 2005-314613 A Japanese Patent Laid-Open No. 2006-064803 JP 2006-342227 A Special table 2007-515545 gazette JP 2007-086254 A JP 2007-269850 A JP 2007-003679 A JP 2003-012859 A JP 2007-304376 A

As described above, the solubility in polymers in the film-forming process, especially cellulose ester, is insufficient in the past, and this causes adverse effects on plasticizer contamination and film surface conditions in the film-casting process and the subsequent function-imparting process. No practical method for obtaining the desired optical film has been found.
Therefore, the object of the present invention is to solve the problems of the prior art as described above, without any smoke, oil contamination or foreign matter failure in the manufacturing process, and without having to reduce the casting speed in the manufacturing process, the stripping property and the drying speed. It is also possible to provide a polymer film obtained by a relatively easy operation with excellent handling properties. Moreover, it is providing the retardation film using such a polymer film, the outstanding polarizing plate, and a liquid crystal display device.

  As a result of intensive studies, the present inventors have found that the problems of the prior art can be solved by using a plasticizer that satisfies a specific condition. That is, the following problems have been solved by the following means.

1. A polymer film comprising a polymer and a high molecular weight plasticizer, the high molecular weight plasticizer comprising:
At least an aliphatic high molecular weight plasticizer (PA) which is a polycondensate obtained using an aliphatic dicarboxylic acid and an aliphatic diol as raw materials and has a number average molecular weight of 700 to 10,000,
A polycondensate obtained by using at least one of an aliphatic diol and a diol having at least one aromatic ring and a dicarboxylic acid having at least one aromatic ring as raw materials, and having a number average molecular weight of 700 to 10,000 An aromatic high molecular weight plasticizer (PB);
A total content of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 2 to 30% by mass with respect to the polymer, and the fat A polymer film having a mass ratio of the aromatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) of 1/9 to 9/1.
2. The aliphatic dicarboxylic acid used in the aliphatic high molecular weight plasticizer (PA) is at least one aliphatic dicarboxylic acid having 2 to 20 carbon atoms, and at least one used in the aromatic high molecular weight plasticizer (PB). The dicarboxylic acid having an aromatic ring is at least one aromatic dicarboxylic acid having 8 to 20 carbon atoms, and is used for the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB). The group diol is an aliphatic diol having 2 to 20 carbon atoms or an alkyl ether diol having 4 to 20 carbon atoms, and the aromatic ring-containing diol used in the aromatic high molecular weight plasticizer (PB) has 6 to 20 carbon atoms. 2. The polymer film as described in 1 above, which is an aromatic ring-containing diol.
3. The aliphatic dicarboxylic acid used in the aliphatic high molecular weight plasticizer (PA) is malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, cyclohexanedicarboxylic acid, maleic acid or fumaric acid, Dicarboxylic acid having at least one aromatic ring used for aromatic high molecular weight plasticizer (PB) is phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1, 3. The polymer film as described in 1 or 2 above, which is 8-naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid.
4). The aliphatic diol used in the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl) Glycol), 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dicyclohexyldiol or dicyclohexyldimethanol, and at least one kind used for the aromatic high molecular weight plasticizer (PB). Diol having an aromatic ring is bisphenol A, 1,4-dihydroxybenzene The polymer film of others according to any one of the above 1 to 3 benzene-1,4-dimethanol.
5. The aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) are obtained using an aliphatic monocarboxylic acid or an aliphatic monoalcohol further containing an aliphatic group having 1 to 22 carbon atoms. And an aromatic ring-containing monocyclic compound containing at least one selected from an aromatic ring-containing group having 6 to 20 carbon atoms, an aliphatic carbonyl group having 2 to 22 carbon atoms, and an aromatic carbonyl group having 7 to 20 carbon atoms. 5. The polymer film according to any one of 1 to 4 obtained by using a carboxylic acid or an aromatic ring-containing monoalcohol.
6). 6. The polymer film as described in 5 above, wherein the aliphatic monocarboxylic acid is acetic acid, the aliphatic monoalcohol is ethylhexanol, and the aromatic ring-containing monocarboxylic acid is benzoic acid.
7). The mixing ratio (mass ratio) of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 2/8 to 8/2, and the aromatic high molecular weight plasticizer (PB) 7. The polymer film as described in any one of 1 to 6 above, wherein the dicarboxylic acid having an aromatic ring used is 25 to 100 mol% of the total dicarboxylic acid.
8). 8. The polymer film as described in any one of 1 to 7 above, wherein the content of a component having a number average molecular weight of 500 or less in the high molecular weight plasticizer is 10% by mass or less.
9. 9. The polymer film as described in any one of 1 to 8 above, wherein the mass reduction rate when the high molecular weight plasticizer is heated in air at 140 ° C. for 60 minutes is 1% or less.
10. 10. The polymer film as described in any one of 1 to 9 above, which is a polyester film produced by a solution casting method or a melt casting method and having a thickness of 20 to 200 μm.
11. 11. The polymer film as described in any one of 1 to 10 above, wherein the in-plane retardation (Re) is from 0 to 300 nm and the retardation in the thickness direction (Rth) is from -200 to +300 nm.
12 A polymer film is stretched by 3% to 400% during film formation or after film formation, the in-plane retardation (Re) is 30 to 200 nm, and the thickness direction retardation (Rth) is −50 to +250 nm. The polymer film according to any one of 1 to 11 above.
13. The retardation film using the polymer film in any one of said 1-12.
14 14. A polarizing plate having at least one of the polymer film described in any one of 1 to 12 or the retardation film described in 13 above.
15. 15. A liquid crystal display device comprising at least one of the polymer film described in any one of 1 to 12 above, the retardation film described in 13 above, or the polarizing plate described in 14 above.

  The polymer film of the present invention has good compatibility with the plasticizer and the polymer, particularly cellulose ester, during casting, and is excellent in surface shape. There is no smoke, oil contamination or foreign matter failure in the manufacturing process, and casting in the manufacturing process. It is possible to increase the peelability and the drying speed without reducing the speed. Moreover, it is excellent in handling property, can be obtained by a relatively easy operation, and can adjust the expression of retardation as an optical film. Further, it is possible to provide a polymer film having reduced moisture permeability, excellent durability in the form of a polarizing plate, and small dimensional change. In addition, it is possible to provide a retardation film using such a polymer film, an excellent polarizing plate, and a liquid crystal display device.

  Hereinafter, the polymer film of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

The polymer film of the present invention is a polymer film containing a polymer and a high molecular weight plasticizer, wherein the high molecular weight plasticizer is
At least an aliphatic high molecular weight plasticizer (PA) which is a polycondensate obtained using an aliphatic dicarboxylic acid and an aliphatic diol as raw materials and has a number average molecular weight of 700 to 10,000,
A polycondensate obtained by using at least one of an aliphatic diol and a diol having at least one aromatic ring (aromatic diol) and a dicarboxylic acid having at least one aromatic ring (aromatic dicarboxylic acid) as raw materials An aromatic high molecular weight plasticizer (PB) having a number average molecular weight of 700 to 10,000,
A total content of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 2 to 30% by mass with respect to the polymer, and the fat It is a polymer film whose mass ratio of the aromatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 1/9 to 9/1.

<< Polymer film and method for producing the same >>
[polymer]
First, the polymer that can be used for the polymer film of the present invention will be described.
Examples of the polymer constituting the polymer film of the present invention include cellulose esters (for example, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose tripropionate, cellulose diacetate), polyolefins (for example, polyethylene, polypropylene). , Norbornene-based polymers), vinyl polymers (eg, polymethacrylates, polyacrylates, polystyrene, polyvinyl acetate, etc.), polycarbonates, cycloolefin polymers, polyarylate, polysulfone, polyamides, polyimides, cycloolefin copolymers, polynorbornene The polymer which can comprise the polymer film which can be used for optical uses etc. etc. can be mentioned. The polymer preferably has a hydrophilic structure such as a hydroxyl group, an amide, an imide, or an ester in the main chain or side chain in order to achieve appropriate moisture permeability. In the present invention, a copolymer may be used or a polymer mixture may be used. As said polymer, a cellulose ester and a vinyl polymer (for example, polymethacrylic acid ester, polyacrylic acid ester, etc.) are more preferable. As the polymer, cellulose ester is more preferable.

  When the polymer film of the present invention is produced, the polymer used as a raw material can be a powder or a particulate material, and a pelletized one can also be used. The water content of the polymer is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, and most preferably 0.3% by mass or less. Moreover, it is preferable that the said moisture content is 0.2 mass% or less depending on the case. When the water content of the polymer is not within the preferred range, it is preferable to use the polymer after drying the polymer by drying air or heating. These polymers may be used alone or in combination of two or more polymers.

  Examples of the cellulose ester that is a preferable material of the polymer include a cellulose ester compound and a compound having an ester-substituted cellulose skeleton obtained by introducing a functional group biologically or chemically using cellulose as a raw material. In addition, as a polymer as a main component of the polymer film of this invention, it is preferable to use the above-mentioned cellulose ester. Here, the “polymer as the main component” indicates a polymer when it is composed of a single polymer, and when it is composed of a plurality of polymers, it is the most mass fraction of the constituent polymers. Indicates a high polymer.

The cellulose ester is an ester of cellulose and acid. The acid constituting the ester is preferably an organic acid, more preferably a carboxylic acid, more preferably a fatty acid and aromatic acid having 2 to 22 carbon atoms, and a lower fatty acid and carbon atom having 2 to 6 carbon atoms. An aromatic acid having 7 to 13 carbon atoms is more preferable, and a lower fatty acid having 2 to 4 carbon atoms and an aromatic acid having 8 carbon atoms are particularly preferable.
The cellulose ester is preferably an ester of cellulose and a carboxylic acid, and all or part of the hydrogen atoms of the hydroxyl groups present at the 2-position, 3-position and 6-position of the glucose unit constituting the cellulose are acyl groups. It is preferably substituted. Examples of the acyl group include, for example, acetyl group, propionyl group, butyryl group, isobutyryl group, pivaloyl group, heptanoyl group, hexanoyl group, octanoyl group, decanoyl group, dodecanoyl group, tridecanoyl group, tetradecanoyl group, hexadecanoyl group, and hexadecanoyl group. Examples include a noyl group, an octadecanoyl group, a cyclohexanecarbonyl group, a dicyclohexylcarbonyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, and a cinnamoyl group. As the acyl group, acetyl group, propionyl group, butyryl group, dodecanoyl group, octadecanoyl group, pivaloyl group, oleoyl group, benzoyl group, naphthylcarbonyl group, cinnamoyl group are preferable, acetyl group, propionyl group, butyryl group A benzoyl group is particularly preferred. The cellulose ester may be an ester of cellulose and a plurality of acids. The cellulose ester may be substituted with a plurality of acyl groups.

  Further preferred cellulose esters are described. That is, when the substitution degree of the acetyl group (2 carbon atoms) substituted on the hydroxyl group of cellulose is SA and the substitution degree of the acyl group of 3 or more carbon atoms substituted on the hydroxyl group of cellulose is SB, SA and By adjusting the SB, the optical properties of the polymer film of the present invention (in-plane retardation (Re) expression, thickness direction retardation (Rth) expression, and humidity dependency thereof are adjusted). Depending on the optical properties required for the polymer film of the present invention, SA + SB is appropriately adjusted, but preferably 2.00 ≦ SA + SB ≦ 3.00, more preferably 2.20 ≦ SA + SB ≦ 2.95. More preferably, 2.30 ≦ SA + SB ≦ 2.95, and particularly preferably 2.45 ≦ SA + SB ≦ 2.94. , SA, SB is not particularly limited as long as 0-3. In particular, preferred as SB is 0-1.

  The cellulose ester can be synthesized by a known method. For example, the basic principle of the cellulose ester synthesis method is described in Nobuhiko Umeda et al., Wood Chemistry pages 180-190 (Kyoritsu Shuppan, 1968). The degree of polymerization of the cellulose ester is preferably from 150 to 500, more preferably from 200 to 400, and even more preferably from 220 to 350 in terms of viscosity average degree of polymerization. The viscosity average degree of polymerization can be measured according to the description of Uda et al.'S intrinsic viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pages 105-120, 1962). The method for measuring the viscosity average degree of polymerization is also described in JP-A-9-95538. The raw material cotton of cellulose ester and the synthesis method are also described in pages 7 to 12 of the Japan Society of Invention Disclosure (Public Technical Number 2001-1745, published on March 15, 2001, Japan Society of Invention).

[High molecular weight plasticizer]
The high molecular weight plasticizer used in the polymer film of the present invention is a polycondensate obtained from a mixture containing at least an aliphatic dicarboxylic acid and an aliphatic diol, and has a number average molecular weight of 700 to 10,000. A polycondensate obtained from a mixture comprising an agent (PA), a dicarboxylic acid having at least one aromatic ring, and at least one of an aliphatic diol and an aromatic ring-containing diol, and has a number average molecular weight of 700 to And a mass ratio of the aliphatic high molecular weight plasticizer (PA) to the aromatic high molecular weight plasticizer (PB) is 1/9. ~ 9/1.

  In solution casting, a plasticizer is an essential material for accelerating the volatilization rate of the solvent and reducing the amount of residual solvent. Also, in the melt film forming method, the plasticizer prevents coloring and film strength deterioration. It is a useful material. Furthermore, by adding the high molecular weight plasticizer according to the present invention to the polymer film, it has useful effects in terms of film modification such as improvement of mechanical properties, flexibility, water absorption resistance, and moisture permeability reduction. Show. Moreover, in this invention, as shown in the Example mentioned later, it is very effective for the improvement of the handling characteristic in a manufacturing process. Furthermore, the polymer plasticizer mixture of the present invention has characteristics that allow the optical characteristics to be arbitrarily controlled.

Here, the high molecular weight plasticizer in the present invention has a number average molecular weight of 700 to 10000, preferably a number average molecular weight of 800 to 8000, more preferably a number average molecular weight of 850 to 5000, and particularly preferably. The number average molecular weight is 900-3500.
If the number average molecular weight is less than 700, the component contains a large amount of components having a number average molecular weight of 500 or less, and the low molecular weight component volatilizes in the process during production, causing a problem of contaminating the production machine. On the other hand, when the number average molecular weight is larger than 10,000, the compatibility with a polymer such as cellulose ester is remarkably deteriorated, and these high molecular weight plasticizers bleed out from the polymer film such as a cellulose ester film. Is significantly worsened. The content of the component having a number average molecular weight of 500 or less in the high molecular weight plasticizer is preferably 10% by mass or less. The high molecular weight plasticizer preferably has a mass reduction rate of 1% or less when heated at 140 ° C. for 60 minutes.

  The high molecular weight plasticizer of the present invention may be liquid or solid at the ambient temperature or humidity used. Preferably, the melting point is −100 ° C. to 250 ° C., more preferably the melting point is −100 ° C. to 200 ° C., and the melting point is particularly preferably −100 ° C. to 150 ° C.

Further, the smaller the color of the high molecular weight plasticizer, the better, and it is particularly preferable that it is colorless. The high molecular weight plasticizer is preferably thermally stable at a higher temperature, the decomposition start temperature is preferably 150 ° C. or higher, and more preferably 200 ° C. or higher. The addition amount may be as long as it does not adversely affect the optical properties and mechanical properties, and the blending amount is appropriately selected within the range not impairing the object of the present invention. The content of the high molecular weight plasticizer in the polymer film of the present invention is 2 to 30% by mass, preferably 3 to 25% by mass, particularly preferably 5 to 25% by mass, based on the polymer amount.
Hereinafter, the high molecular weight plasticizer used in the present invention will be described in detail with specific examples.

First, an aliphatic high molecular weight plasticizer (PA) having a number average molecular weight of 700 to 10,000 and a polycondensate obtained from an aliphatic dicarboxylic acid and an aliphatic diol and optionally an aliphatic monocarboxylic acid or an aliphatic monoalcohol. )
As the aliphatic dicarboxylic acid, an alkylene dicarboxylic acid having 2 to 20 carbon atoms may be optionally formed as a ring. For example, oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, Examples include pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and dicyclohexanedicarboxylic acid. Among these, preferable aliphatic dicarboxylic acids include malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and 1,4-cyclohexanedicarboxylic acid. Particularly preferred are succinic acid and adipic acid.
One type of aliphatic dicarboxylic acid may be used, or two or more types may be used.

  The aliphatic diol used for the aliphatic high molecular weight plasticizer (PA) is preferably an aliphatic diol having 2 to 20 carbon atoms or an alkyl ether diol having 4 to 20 carbon atoms, and these form a cyclic structure. Also good. First, examples of the aliphatic diol having 2 to 20 carbon atoms include alkyl diols and aliphatic cyclic diols, such as 1,2-ethanediol (also referred to as ethanediol or ethylene glycol), 1,2- Propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2 , 2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1 , 3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decane Examples include diol, 1,12-octadecanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like.

  Preferred aliphatic diols include ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1 , 4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, particularly preferably ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. Ethanediol is most preferred.

The alkyl ether diol having 4 to 20 carbon atoms used for the aliphatic high molecular weight plasticizer (PA) is preferably polytetramethylene ether glycol, polyethylene ether glycol, polypropylene ether glycol or a combination thereof. it can. Although the average degree of polymerization is not particularly limited, it is preferably 2 to 20, more preferably 2 to 10, further 2 to 5, and particularly preferably 2 to 4. Examples of these are typically useful commercially available polyether glycols, such as Carbowax resin, Pluronics resin, and Niax resin.
One type of aliphatic diol may be used, or two or more types may be used.

  Furthermore, the aliphatic high molecular weight plasticizer (PA) may be an aliphatic high molecular weight plasticizer in which an aliphatic monocarboxylic acid or an aliphatic monoalcohol is used in combination, and the polyester terminal is sealed with an alkyl group. preferable. This is because the terminal is protected with a hydrophobic functional group, which is effective against deterioration with time at high temperature and high humidity, and is due to the role of delaying hydrolysis of the ester group. For this reason, it is preferable to protect the both ends of the polyester plasticizer of the present invention with an aliphatic monoalcohol residue or an aliphatic monocarboxylic acid residue so as not to become a carboxylic acid or an OH group.

  In this case, the aliphatic monoalcohol residue is preferably a substituted or unsubstituted aliphatic monoalcohol residue having 1 to 30 carbon atoms, more preferably a substituted or unsubstituted aliphatic monoalcohol having 1 to 22 carbon atoms. It is a residue and may contain a cyclic structure. Examples of the aliphatic monoalcohol used to form such an aliphatic monoalcohol residue include methanol, ethanol, propanol, isopropanol, butanol, isobutanol, pentanol, isopentanol, hexanol, isohexanol, and cyclohexyl alcohol. Octanol, isooctanol, 2-ethylhexyl alcohol, nonyl alcohol, isononyl alcohol, tert-nonyl alcohol, decanol, dodecanol, dodecahexanol, dodecaoctanol, allyl alcohol, oleyl alcohol and the like. Each of these can be used alone or in combination of two or more.

  In the case of sealing with an aliphatic monocarboxylic acid residue, the aliphatic monocarboxylic acid residue is preferably a substituted or unsubstituted aliphatic monocarboxylic acid residue having 1 to 30 carbon atoms, more preferably carbon. It is a substituted or unsubstituted aliphatic monocarboxylic acid residue having a number of 1 to 22. Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butanoic acid, hexanoic acid, octanoic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid, cyclohexyl carboxylic acid, dicyclohexyl carboxylic acid, etc. 1 type (s) or 2 or more types can each be used. Of these, preferred are acetic acid, propionic acid, oleic acid, and cyclohexylcarboxylic acid, and particularly preferred are acetic acid and propionic acid.

In the present invention, the aliphatic dicarboxylic acid used in the aliphatic high molecular weight plasticizer (PA) is at least one aliphatic dicarboxylic acid having 2 to 20 carbon atoms, and the aromatic high molecular weight plasticizer (PB) The aromatic dicarboxylic acid used is at least one aromatic dicarboxylic acid having 8 to 20 carbon atoms, and is used for the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB). The diol is an aliphatic diol having 2 to 20 carbon atoms or an alkyl ether diol having 4 to 20 carbon atoms, and the aromatic ring-containing diol used in the aromatic high molecular weight plasticizer (PB) is an aromatic having 6 to 20 carbon atoms. An aromatic ring-containing diol is preferred.
The aliphatic dicarboxylic acid used in the aliphatic high molecular weight plasticizer (PA) is malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, cyclohexanedicarboxylic acid, maleic acid or fumaric acid. The aromatic dicarboxylic acid used in the aromatic high molecular weight plasticizer (PB) is phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid. An acid, 2,8-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid is preferred.
In addition, aliphatic diols used for the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) are ethanediol, 1,2-propanediol, 1,3-propanediol, 1, 2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol ( Neopentyl glycol), 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dicyclohexyldiol or dicyclohexyldimethanol, and the aromatic used for the aromatic high molecular weight plasticizer (PB) Group ring-containing diol is bisphenol A, 1,4-dihydroxybenzene or benzene It is preferably 1,4-dimethanol.
The aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) are aliphatic monocarboxylic acids containing aliphatic groups having 1 to 22 carbon atoms, or aliphatic monoalcohols. An aromatic ring containing at least one selected from an aromatic ring-containing group having 6 to 20 carbon atoms, an aliphatic carbonyl group having 2 to 22 carbon atoms, and an aromatic carbonyl group having 7 to 20 carbon atoms It is preferably obtained using a monocarboxylic acid or an aromatic ring-containing monoalcohol.
The aliphatic monocarboxylic acid is acetic acid, propionic acid, butanoic acid, hexanoic acid, octanoic acid, cyclohexyl carboxylic acid or dicyclohexyl carboxylic acid, and the aliphatic monoalcohol is methanol, ethanol, propanol, butanol, pentanol, More preferred is hexanol, octanol, nonanol, decanol or tridecanol, and the aromatic ring-containing monocarboxylic acid is benzoic acid, phenylacetic acid or cinnamic acid.

  Hereinafter, an aliphatic high molecular weight plasticizer (PA) having a number average molecular weight of 700 to 10,000 and having a repeating unit consisting of an aliphatic dicarboxylic acid and an aliphatic diol, and optionally an aliphatic monocarboxylic acid or an aliphatic monoalcohol. Specific examples are described below, but the present invention is not limited thereto.

PA-1: Condensate composed of ethanediol / succinic acid (1/1 molar ratio) (number average molecular weight 1100)
PA-2: Condensate composed of 1,3-propanediol / glutaric acid (1/1 molar ratio) (number average molecular weight 1500)
PA-3: Condensate consisting of 1,3-propanediol / adipic acid (1/1 molar ratio) (number average molecular weight 900)
PA-4: Condensate (number average molecular weight 1500) consisting of 1,3-propanediol / ethylene glycol / adipic acid (1/1/2 molar ratio)

PA-5: Condensate (number average molecular weight 1400) consisting of 2-methyl-1,3-propanediol / adipic acid (1/1 molar ratio)
PA-6: Acetyl ester of both ends of the condensate composed of ethanediol / succinic acid / adipic acid (2/1/1 molar ratio) (number average molecular weight 1000)
PA-7: Condensate (number average molecular weight 1800) consisting of 1,4-cyclohexanediol / succinic acid (1/1 molar ratio)

PA-8: butyl esterified product (number average molecular weight 1200) at both ends of the condensate consisting of 1,3-propanediol / succinic acid (1/1 molar ratio)
PA-9: A cyclohexyl esterified product (number average molecular weight 1500) at both ends of a condensate composed of 1,3-propanediol / glutaric acid (1/1 molar ratio)
PA-10: Acetyl esterified product (number average molecular weight 3000) at both ends of a condensate composed of ethanediol / succinic acid (1/1 molar ratio)
PA-11: Isononyl esterified product (number average molecular weight 1500) at both ends of a condensate composed of 1,3-propanediol / ethylene glycol / adipic acid (1/1/2 molar ratio)

PA-12: Propyl ester at both ends of a condensate composed of 2-methyl-1,3-propanediol / adipic acid (1/1 molar ratio) (number average molecular weight 1300)
PA-13: Acetyl ester at both ends of a condensate composed of 2-methyl-1,3-propanediol / adipic acid (1/1 molar ratio) (number average molecular weight 1700)

PA-14: Isononyl esterified product (number average molecular weight 1500) at both ends of a condensate composed of 2-methyl-1,3-propanediol / adipic acid (1/1 molar ratio)
PA-15: butyl esterified product (number average molecular weight 1100) at both ends of the condensate consisting of 1,4-butanediol / adipic acid (1/1 molar ratio)
PA-16: Condensate (number average molecular weight 2800) composed of poly (average polymerization degree 5) propylene ether glycol / succinic acid (1/1 molar ratio)

PA-17: Condensate (number average molecular weight 2300) composed of poly (average polymerization degree 3) ethylene ether glycol / glutaric acid (1/1 molar ratio)
PA-18: Condensate (number average molecular weight 2200) composed of poly (average polymerization degree 4) propylene ether glycol / adipic acid (1/1 molar ratio)
PA-19: Polyester (average polymerization degree 5) propylene ether glycol / succinic acid (1/1 molar ratio) condensate butyl esterified product (number average molecular weight 1900)

PA-20: poly (average polymerization degree 3) 2-ethylhexyl esterified product (number average molecular weight 2500) at both ends of a condensate composed of ethylene ether glycol / glutaric acid (1/1 molar ratio)
PA-21: Polyester (average degree of polymerization 4) propylene ether glycol / adipic acid (1/1 molar ratio) condensate of both end acetyl ester (number average molecular weight 1500)
PA-22: Propionyl esterified product (number average molecular weight 1900) at both ends of a condensate composed of poly (average polymerization degree 4) propylene ether glycol / phthalic acid (1/1 molar ratio)
PA-23: Condensate composed of ethanediol / adipic acid (1/1 molar ratio) (number average molecular weight 1000)

  These specific examples described above confirmed that the abundance having a number average molecular weight of 500 or less was 10% by mass or less. Further, the mass reduction rate when heated at 200 ° C. for 10 minutes by the thermobalance method was 5% or less. It was also confirmed that the mass reduction rate when heated at 140 ° C. for 60 minutes was 1% or less. In addition, components having a number average molecular weight of 10,000 or more were not recognized.

Next, a dicarboxylic acid having a number average molecular weight of 700 to 10,000 and containing at least one aromatic ring and an aliphatic diol or an aromatic ring-containing diol and optionally an aliphatic dicarboxylic acid, an aliphatic monocarboxylic acid, an aliphatic mono An aromatic high molecular weight plasticizer (PB), which is a polycondensate composed of an alcohol, an aromatic ring-containing monocarboxylic acid, or an aromatic ring-containing monoalcohol, is described. Here, when the dicarboxylic acid containing an aromatic ring is used in combination with an aliphatic dicarboxylic acid, it may be at least 10 to 100 mol%, preferably 25 to 100 mol%, based on the total number of moles of the dicarboxylic acid. More preferably, it is 33-100 mol%, Most preferably, it is 40-100 mol%.
Of dicarboxylic acids containing an aromatic ring, aromatic dicarboxylic acids having 8 to 20 carbon atoms are preferably used. Examples of the aromatic dicarboxylic acid having 8 to 20 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,8- There are naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid. Among these, preferable dicarboxylic acids containing an aromatic ring are phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, and 1,4-naphthalenedicarboxylic acid, and particularly phthalic acid and terephthalic acid. . As the aliphatic dicarboxylic acid optionally used in combination with the aromatic high molecular weight plasticizer (PB), the aliphatic dicarboxylic acid described in the above-mentioned aliphatic high molecular plasticizer (PA) can be used in the same manner.

Similarly, the aliphatic diol described in the above-mentioned aliphatic polymer plasticizer (PA) can be used for the aliphatic diol used in the aromatic high molecular weight plasticizer (PB), and the alkyl ether having 4 to 20 carbon atoms. Diols can be used as well.
Next, in the aromatic high molecular weight plasticizer (PB), an aromatic ring-containing diol can also be used as the diol. The aromatic ring-containing diol is preferably at least one diol selected from aromatic diols having 6 to 20 carbon atoms, such as bisphenol A, 1,2-hydroxybenzene, 1,3-dihydroxybenzene, 1, Examples include 4-dihydroxybenzene and benzene-1,4-dimethanol, and bisphenol A, 1,4-dihydroxybenzene, and benzene-1,4-dimethanol are preferable.

  Further, in the aromatic high molecular weight plasticizer (PB), it is also preferable to use an aliphatic monocarboxylic acid, an aliphatic monoalcohol, an aromatic ring-containing monocarboxylic acid or an aromatic ring-containing monoalcohol in some cases. In that case, for the aliphatic monocarboxylic acid and the aliphatic monoalcohol, the aliphatic monocarboxylic acid and the aliphatic monoalcohol described in the above-mentioned aliphatic polymer plasticizer (PA) can be used. Alkyl ether diols can be used as well.

Alternatively, for the aromatic ring-containing monoalcohol, at least one selected from an aromatic ring-containing group having 6 to 20 carbon atoms, an aliphatic carbonyl group having 2 to 22 carbon atoms, and an aromatic carbonyl group having 7 to 20 carbon atoms. It is preferable to contain, for example, phenol, cresol, benzyl alcohol, phenylethanol, phenethyl alcohol, 1-naphthyl alcohol, etc., preferably benzyl alcohol and phenylethanol.
The aromatic ring-containing monocarboxylic acid is at least selected from an aromatic ring-containing group having 6 to 20 carbon atoms, an aliphatic carbonyl group having 2 to 22 carbon atoms, and an aromatic carbonyl group having 7 to 20 carbon atoms. 1 type is preferable, for example, benzoic acid, p-tert-butylbenzoic acid, p-tert-amylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, n-propylbenzoic acid Aminobenzoic acid, acetoxybenzoic acid, phenylacetic acid, cinnamic acid and the like, preferably benzoic acid, phenylacetic acid and cinnamic acid. Each of these can be used alone or in combination of two or more.

Although the specific example of the aromatic high molecular weight plasticizer (PB) described above is described below, it is not limited to these.
PB-1: Condensate composed of succinic acid / phthalic acid / ethanediol / (1/1/2 molar ratio) (number average molecular weight 900)
PB-2: Condensate composed of glutaric acid / isophthalic acid / 1,3-propanediol (1/1/2 molar ratio) (number average molecular weight 1300)
PB-3: Condensate (number average molecular weight 1200) consisting of adipic acid / terephthalic acid / 1,2-propanediol (1/1/2 molar ratio)
PB-4: Condensate (number average molecular weight 3000) consisting of succinic acid / terephthalic acid / ethanediol / 1,4-cyclohexanedimethanol (1/1/1/1 molar ratio)

PB-5: Condensate comprising succinic acid / glutaric acid / adipic acid / terephthalic acid / isophthalic acid / ethanediol / 1,2-propanediol (1/1/1/1/1/3/2 molar ratio) Number average molecular weight 2500)
PB-6: Condensate (number average molecular weight 2800) consisting of succinic acid / adipic acid / terephthalic acid / ethanediol / 1,2-propanediol (1/1/1/2/1 molar ratio)
PB-7: Condensate (number average molecular weight 2000) comprising succinic acid / adipic acid / 1,4-naphthalenedicarboxylic acid / ethanediol / 1,2-propanediol (1/1/1/2/1 molar ratio)
PB-8: Condensate composed of succinic acid / terephthalic acid / poly (average polymerization degree 5) propylene ether glycol / 1,2-propanediol (2/1/1/2 molar ratio) (number average molecular weight 2500)

PB-9: Succinic acid / terephthalic acid / poly (average polymerization degree 3) condensate (number average molecular weight 3500) consisting of ethylene ether glycol / 1,2-propanediol (1/3/2/2 molar ratio)
PB-10: acetyl esterified product of both ends of a condensate (number average molecular weight 2100) comprising succinic acid / terephthalic acid / ethanediol / (1/1/2 molar ratio) PB-11: glutaric acid / isophthalic acid / A cyclohexyl esterified product of both ends of a condensate (number average molecular weight 1500) composed of 1,3-propanediol (1/1/2 molar ratio) PB-12: adipic acid / terephthalic acid / 1,2-propanediol ( 2-ethylhexyl esterified product of both ends of a condensate (number average molecular weight 2500) consisting of (1/1/2 molar ratio)

PB-13: Isononyl esterified product of both ends of a condensate (number average molecular weight 3000) consisting of succinic acid / terephthalic acid / ethanediol / 1,4-cyclohexanedimethanol (1/1/1/1 molar ratio) PB-14: Condensate comprising succinic acid / glutaric acid / adipic acid / terephthalic acid / isophthalic acid / ethanediol / 1,2-propanediol (1/1/1/1/1/3/2 molar ratio) Propyl ester of both ends with a number average molecular weight of 3000) PB-15: Succinic acid / adipic acid / terephthalic acid / ethanediol / 1,2-propanediol (1/1/1/2/1 molar ratio) 2-ethylhexyl esterified product of both ends of the condensate (number average molecular weight 3000) PB-16: succinic acid / adipic acid / 1,4-naphthalenedicarboxylic acid / ethanedio Benzoate esterified product of both ends of a condensate (number average molecular weight 3000) consisting of ru / 1,2-propanediol (1/1/1/2/1 molar ratio)

PB-17: both succinic acid / terephthalic acid / poly (average degree of polymerization 5), a condensate (number average molecular weight 3500) consisting of propylene ether glycol / 1,2-propanediol (2/1/1/2 molar ratio) Terminal 2-ethylhexyl esterified product PB-18: Condensate composed of succinic acid / terephthalic acid / poly (average polymerization degree 4) ethylene ether glycol / 1,2-propanediol (1/3/2/2 molar ratio) 2-ethylhexyl esterified product of both ends of (number average molecular weight 2500) PB-19: both of condensate (number average molecular weight 2500) consisting of succinic acid / phthalic acid / ethanediol / (1/1/2 molar ratio) Terminal acetyl ester PB-20: Succinic acid / isophthalic acid / phthalic acid / terephthalic acid / ethanediol / 1,3-propanediol (1/1/1 / 1/2/2 molar ratio) of the condensate (number average molecular weight 1300) at both ends of the acetyl esterified product

PB-21: Benzoyl esterified product at both ends of a condensate (number average molecular weight 900) composed of adipic acid / terephthalic acid / 1,2-propanediol (1/1/2 molar ratio) PB-22: Succinic acid / Propionyl esterified product of both ends of a condensate (number average molecular weight 3000) consisting of terephthalic acid / ethanediol / 1,4-cyclohexanedimethanol (1/1/1/1 molar ratio)

PB-23: Condensate comprising succinic acid / glutaric acid / adipic acid / terephthalic acid / isophthalic acid / ethanediol / 1,2-propanediol (1/1/1/1/2/3/3 molar ratio) PB-24: Succinic acid / terephthalic acid / poly (average polymerization degree 3) ethylene ether glycol / 1,2-propanediol (1/3/2/2 mol) Ratio) condensate (number average molecular weight 2500) acetyl esterified product at both ends PB-25: succinic acid / bisphenol A (1/1 molar ratio) condensate (number average molecular weight 2000)
PB-26: Condensate (number average molecular weight 2500) consisting of succinic acid / terephthalic acid / ethanediol / bisphenol A (2/1/1/2 molar ratio)

PB-27: Condensate composed of succinic acid / 2,6-naphthalenedicarboxylic acid / bisphenol A / propanediol (1/2/2/1 molar ratio) (number average molecular weight 1900)
PB-28: Condensate (number average molecular weight 2500) comprising succinic acid / adipic acid / 2,6-naphthalenedicarboxylic acid / bisphenol A / diethylene glycol (1/1/2/2/2 molar ratio)
PB-29: 2-ethylhexyl esterified product of both ends of a condensate (number average molecular weight 2500) consisting of succinic acid / terephthalic acid / ethanediol / bisphenol A (1/2/1/2 molar ratio) PB-30: 2-ethylhexyl esterified product of both ends of a condensate (number average molecular weight 2300) comprising succinic acid / 2,6-naphthalenedicarboxylic acid / bisphenol A / propanediol (1/2/2/1 molar ratio) PB-31 : Condensate composed of succinic acid / bisphenol A (1/1 molar ratio) (number-average molecular weight 2200) acetyl esterified product at both ends PB-32: succinic acid / adipic acid / phthalic acid / terephthalic acid / ethanediol / Acetyl esterified product of both ends of a condensate (number average molecular weight 800) consisting of (5/5/1/9/20 molar ratio) PB-33: Adip Pt-34: adipic acid / phthalic acid Pt-34: acetyl esterified product of acid / phthalic acid / terephthalic acid / ethanediol / (10/5/1/9/20 molar ratio) condensate (number average molecular weight 800) Acid / terephthalic acid / ethanediol / (5/2/3/10 molar ratio) condensate (number average molecular weight 1000) acetyl esterified product at both ends PB-35: succinic acid / adipic acid / phthalic acid / Acetyl ester of both ends of a condensate (number average molecular weight 1000) consisting of ethanediol / (1/1/2/4 molar ratio)

  These specific examples described above confirmed that the abundance having a number average molecular weight of 500 or less was 10% by mass or less. Further, the mass reduction rate when heated at 200 ° C. for 10 minutes by the thermobalance method was 5% or less. It was also confirmed that the mass reduction rate when heated at 140 ° C. for 60 minutes was 1% or less. In addition, components having a number average molecular weight of 10,000 or more were not recognized.

  The synthesis of the high molecular weight plasticizer of the present invention is carried out by a conventional method, a polyesterification reaction of the above-mentioned dicarboxylic acid and a diol, and optionally a monoalcohol or monocarboxylic acid for end-capping, or a hot melt shrinkage by transesterification. The compound can be easily synthesized by any of the methods of interfacial condensation between acid chlorides of these acids and glycols. These polyester plasticizers are described in detail in Koichi Murai, “Plasticizers, Theory and Applications” (Koshobo Co., Ltd., first edition published on March 1, 1973). Also, JP-A Nos. 05-155809, 05-155810, JP-A-5-97073, JP-A-2006-259494, JP-A-07-330670, JP-A-2006-342227, JP-A-2007-003679. The materials described in each publication can also be used.

In the present invention, the addition amount of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) with respect to the polymer is 2 to 30% by mass, and 4 to 25% by mass with respect to the polymer. Particularly preferred is 5 to 22% by mass. If it is less than 2% by mass, it is not preferable from the viewpoint of insufficient hydrophobicity or plasticization. If it exceeds 30% by mass, it is not preferable from the viewpoint of occurrence of bleeding out.
The mass ratio (PA / PB) of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 1/9 to 9/1, and 2/8 to 8/2. It is preferably 4/6 to 8/2, more preferably 5/5 to 8/2.
When the polymer film is composed of two or more layers having different compositions, (PA) and (PB) exist separately in different layers, and the mass ratio of (PA) and (PB) to the polymer of the entire polymer film (PA / PB) may be 1/9 to 9/1.
When the mass ratio of (PA) and (PB) is outside the range of 1/9 to 9/1, the compatibility with the cellulose ester is slightly insufficient, and the roll dirt and the edge cutting state are slightly deteriorated. It is not preferable from the viewpoint of accompanying deterioration of plate durability.

  In the present invention, a mixing ratio (mass ratio) of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 2/8 to 8/2, and the aromatic high molecular weight plasticizer It is preferable that the dicarboxylic acid having an aromatic ring used in (PB) is 25 to 100 mol% of the total dicarboxylic acid.

(Other polymer plasticizers)
In the present invention, not only an aliphatic high molecular weight plasticizer (PA) and an aromatic high molecular weight plasticizer (PB) but also other high molecular weight plasticizers can be used. Examples of the polymer plasticizer include polyester polyurethane plasticizer, aliphatic hydrocarbon polymer, alicyclic hydrocarbon polymer, acrylic polymer such as polyacrylic acid ester, polymethacrylic acid ester (as the ester group, Methyl, ethyl, propyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, octyl, 2-ethylhexyl, nonyl, isononyl, tert-nonyl, dodecyl, tridecyl, stearyl Group, oleyl group, benzyl group, phenyl group, etc.), polyvinyl isobutyl ether, vinyl-based polymers such as poly N-vinylpyrrolidone, polystyrene and copolymers thereof (for example, maleic anhydride copolymer), poly-4-hydroxystyrene Styrene polymer such as polyethylene, polyethylene Kishido, polyether such as polyethylene oxide and polypropylene oxide, polyamides, polyurethanes, polyureas, phenol - formaldehyde condensates, urea - formaldehyde condensate, vinyl acetate, and the like.

Among these, it is particularly preferable to use an acrylic polymer in combination. In the present invention, the acrylic polymer is preferably a homopolymer or copolymer synthesized from a monomer such as acrylic acid or alkyl methacrylate.
Examples of the acrylate monomer having no aromatic ring include, for example, methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i, s-, t-), acrylic Pentyl acid (n-, i-, s-), hexyl acrylate (n, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n -, I-), myristyl acrylate (n-, i-), acrylic acid (2-ethyl hesyl), acrylic acid (ε-caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl) Acrylic acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), acrylic acid (2-methoxyethyl), Acrylic acid (2-ethoxyethyl), etc., or the acrylic acid ester may include those obtained by changing the methacrylic acid ester. Examples of the acrylic monomer used for the acrylic polymer having an aromatic ring include benzyl acrylate and phenyl acrylate.

  When the acrylic polymer is a copolymer, it is composed of X (monomer component having a hydrophilic group) and Y (monomer component having no hydrophilic group), and X: Y (molar ratio) is 1: 1 to 1:99. Is preferred. It is preferable that content of an acrylic polymer is 1-20 mass% with respect to a cellulose ester. These acrylic polymers can be synthesized with reference to the method described in JP-A-2003-12859.

[Polymer solution]
The polymer film of the present invention can be produced, for example, from a polymer solution containing the polymer or various additives by a solution casting film forming method or a melt film forming method. Below, the polymer solution which can be used for the solution casting film forming method is demonstrated.

(solvent)
As a main solvent of a polymer solution (preferably a cellulose ester solution) used for production of the solution casting of the present invention, an organic solvent which is a good solvent for the polymer can be preferably used. As such an organic solvent, an organic solvent having a boiling point of 80 ° C. or lower is more preferable from the viewpoint of reducing the drying load. The boiling point of the organic solvent is more preferably 10 to 80 ° C, and particularly preferably 20 to 60 ° C. Moreover, the organic solvent whose boiling point is 30-45 degreeC depending on the case can also be used suitably as said main solvent.

  Examples of such a main solvent include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, which may have a branched structure or a cyclic structure. The main solvent may have two or more functional groups of esters, ketones, ethers and alcohols (that is, —O—, —CO—, —COO—, —OH). Furthermore, the hydrogen atom in the hydrocarbon portion of the ester, ketone, ether and alcohol may be substituted with a halogen atom (particularly a fluorine atom). In addition, the main solvent of the polymer solution (preferably cellulose ester solution) used for the production of the polymer film of the present invention indicates the solvent when it is composed of a single solvent, and is composed of a plurality of solvents. Shows the solvent having the highest mass fraction among the constituent solvents. Preferred examples of the main solvent include halogenated hydrocarbons.

  As said halogenated hydrocarbon, a chlorinated hydrocarbon is more preferable, for example, a dichloromethane, chloroform, etc. are mentioned, A dichloromethane is further more preferable. Examples of the ester include methyl formate, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate. Examples of the ketone include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone.

  Examples of the ether include diethyl ether, methyl-tert-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, 4-methyldioxolane, tetrahydrofuran, methyltetrahydrofuran, anisole, and phenetole. Etc.

Examples of the alcohol include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol, cyclohexanol, and 2-fluoro. Examples include ethanol, 2,2,2-trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol. Preferred is an alcohol having 1 to 4 carbon atoms, more preferred is methanol, ethanol or butanol, and most preferred is methanol or butanol. Examples of the hydrocarbon include n-pentane, cyclohexane, n-hexane, benzene, toluene, xylene and the like.
Examples of the organic solvent having two or more types of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol, 2-butoxyethanol, and methyl acetoacetate.

When the polymer constituting the transparent polymer film of the present invention contains a hydrogen-bonding functional group such as a hydroxyl group, an ester, or a ketone, it is 5 to 30% by mass in the total solvent, more preferably 7 to 25% by mass, and still more preferably. It is preferable from a viewpoint of the peeling load reduction from a casting support body to contain 10-20 mass% alcohol. The polymer containing a hydrogen bonding functional group includes a cellulose ester.
By adjusting the alcohol content, it is possible to easily adjust the expression of Re and Rth of the transparent polymer film produced by the production method of the present invention. Specifically, by increasing the alcohol content, the heat treatment temperature can be set relatively low, and the reach range of Re and Rth can be increased.

  In addition, the polymer solution used for the production of the polymer film of the present invention has a small volatilization ratio with the halogenated hydrocarbon at the beginning of the drying process, has a boiling point of 95 ° C. or higher, and is poor in cellulose ester. It is preferable to contain 1 to 15% by mass, more preferably 1.5 to 13% by mass, and further preferably 2 to 10% by mass of the organic solvent as the solvent. In the present invention, it is effective to contain a small amount of water to increase the solution viscosity and the film strength of the wet film during drying, or to increase the dope strength during casting by the drum method. 0.1 to 5% by mass, more preferably 0.1 to 3% by mass, and particularly 0.2 to 2% by mass.

Although the example of the combination of the organic solvent preferably used as a solvent of the polymer solution used for preparation of the polymer film of this invention is given below, this invention is not limited to these. In addition, the numerical value of a ratio means a mass part.
(1) Dichloromethane / methanol / ethanol / butanol = 80/10/5/5
(2) Dichloromethane / methanol / butanol / water = 80/18/1/1
(3) Dichloromethane / ethanol = 90/10
(4) Dichloromethane / acetone / methanol / propanol = 80/5/5/10

(5) Dichloromethane / methanol / butanol / cyclohexane = 80/8/10/2
(6) Dichloromethane / methyl ethyl ketone / methanol / butanol = 80/10/5/5
(7) Dichloromethane / ethanol / water = 90 / 9.5 / 0.5
(8) Dichloromethane / acetone / methyl ethyl ketone / ethanol / butanol = 68/10/10/7/5
(9) Dichloromethane / cyclopentanone / methanol / pentanol = 80/2/15/3

(10) Dichloromethane / methyl acetate / ethanol / butanol = 70/12/15/3
(11) Dichloromethane / methyl ethyl ketone / methanol / butanol = 80/5/5/10
(12) Dichloromethane / methyl acetate / acetone / methanol / pentanol = 50/20/15/5/10
(13) Dichloromethane / 1,3-dioxolane / methanol / butanol = 70/15/5/10
(14) Dichloromethane / methyl acetate / ethanol = 65/25/10
(15) Dichloromethane / methyl acetate / acetone // ethanol = 50/30/10/10

(16) Dichloromethane / methyl acetate / methanol = 50/40/10
(17) Dichloromethane / acetone / ethyl acetate / butanol / hexane = 69/10/10/10/1
(18) Dichloromethane / methyl acetate / methanol / isobutyl alcohol = 65/15/10/10
(19) Dichloromethane / cyclopentanone / ethanol / butanol = 85/7/3/5

(20) Dichloromethane / methanol / butanol = 83/15/2
(21) Dichloromethane = 100
(22) Acetone / ethanol / butanol = 80/15/5
(23) Methyl acetate / acetone / methanol / butanol = 75/10/10/5
(24) 1,3-dioxolane = 100

(25) Dichloromethane / methanol / butanol / water = 80/18 / 1.5 / 0.5
(26) Dichloromethane / acetone / methanol / butanol / water = 87/5/5 / 2.5 / 0.5
(27) Dichloromethane / methanol = 92/8
(28) Dichloromethane / methanol = 90/10
(29) Dichloromethane / methanol = 87/13
(30) Dichloromethane / ethanol / butanol = 90/9/1

In addition, a detailed description in the case of using a non-halogen organic solvent as a main solvent is described in the Journal of the Invention Association (Technology No. 2001-1745, published on March 15, 2001, Invention Association), and used appropriately. can do. These representative solvents are listed below.
(31) Methyl acetate / acetone / methanol / butanol = 80/10/5/5
(32) Methyl acetate / methyl ethyl ketone / methanol / ethanol = 80/10/5/5
(33) Methyl acetate / cyclopentanone / acetone / methanol / ethanol = 60/15/15/5/5
(34) Methyl acetate / dichloromethane / methanol / ethanol = 70/20/5/5
(35) Acetone / cyclopentanone / ethanol / butanol = 65/20/10/5
(36) Acetone / dichloromethane / methanol = 90/5/5
(37) 1,3-dioxolane / methylene chloride / methanol / butanol = 70/15/10/5

(Solution concentration)
The total concentration of the polymer and the additive containing the high molecular weight plasticizer in the polymer solution to be prepared is preferably 5 to 40% by mass, more preferably 10 to 30% by mass, and most preferably 15 to 30% by mass. The concentration can be adjusted to a predetermined concentration when dissolved in a solvent. Moreover, after preparing a low concentration (for example, 4-10 mass%) solution previously, you may concentrate by evaporating a solvent. Furthermore, after preparing a high concentration solution in advance, it may be diluted.

(Additive)
The said polymer solution used for preparation of the polymer film of this invention can further contain the various liquid or solid additive according to a use in each preparation process. Examples of the additive include an ultraviolet absorber (0.001 to 1% by mass), a fine particle powder (0.001 to 1% by mass) having an average particle size of 5 to 3000 nm, and a fluorine-based surfactant (0 0.001 to 1% by mass), release agent (0.0001 to 1% by mass), deterioration inhibitor (0.0001 to 1% by mass), optical anisotropy control agent (0.01 to 10% by mass), infrared An absorbent (0.001 to 1% by mass) is included. However, the inside of () is the addition amount with respect to 100 mass parts of polymers.

The optical anisotropy controlling agent is an organic compound having a molecular weight of 3000 or less, preferably a compound having both a hydrophobic part and a hydrophilic part. These compounds change the retardation value by orienting between polymer chains. Furthermore, when these compounds are used in combination with the cellulose ester particularly preferably used in the present invention, the hydrophobicity of the film can be improved and the change in humidity of retardation can be reduced.
Moreover, the wavelength dependence of retardation can be effectively controlled by using the ultraviolet absorber or the infrared absorber in combination. The additives used in the polymer film of the present invention are preferably those that are substantially free of volatilization during the drying process. Among the optical anisotropy controlling agents, in the present invention, an optical anisotropy controlling agent can be preferably used according to the target optical properties (Re, Rth values). Specific examples of the additive having an effect of increasing Rth include a plasticizer described on pages 33 to 34 of JP-A-2005-104148 and pages 38 to 89 of JP-A-2005-104148. And an optical anisotropy control agent.

(Preparation of polymer solution)
The polymer solution can be prepared by, for example, JP-A-58-127737, JP-A-61-106628, JP-A-2-276830, JP-A-4-259511, JP-A-5-163301, and 9- No. 95544, No. 10-45950, No. 10-95854, No. 11-71463, No. 11-302388, No. 11-322946, No. 11-322947, No. 11-323017 No. 2000, JP-A-2000-53784, JP-A-2000-273184, and JP-A-2000-273239. Specifically, the polymer and the solvent are mixed and stirred to swell, and optionally cooled or heated to dissolve and then filtered to obtain a polymer solution.

  In the present invention, in order to improve the solubility of the polymer in the solvent, a step of cooling and / or heating the mixture of the polymer and the solvent may be included. When a halogen-based organic solvent is used as the solvent and a cellulose ester is used as the polymer and the mixture of the polymer and the solvent is cooled, the mixture is preferably cooled to −100 to 10 ° C. Moreover, it is preferable to include the process swollen at -10-39 degreeC in the process before a cooling process, and the process heated to 0-39 degreeC in the process after cooling.

When a halogen-based organic solvent is used as the solvent and the mixture of the cellulose ester and the solvent is heated, the method may include a step of dissolving the cellulose ester in the solvent by one or more methods selected from the following (a) or (b): preferable.
(A) Swell at −10 to 39 ° C. and warm the resulting mixture to 0 to 39 ° C.
(B) Swell at −10 to 39 ° C., heat the resulting mixture to 40 to 240 ° C. at 0.2 to 30 MPa, and cool the heated mixture to 0 to 39 ° C.
Furthermore, when using a non-halogen organic solvent as the solvent and cooling the mixture of the cellulose ester and the solvent, it is preferable to include a step of cooling the mixture to −100 to −10 ° C. Moreover, it is preferable to include the process of swelling at -10-55 degreeC in the process before a cooling process, and the process heated to 0-57 degreeC in the process after cooling.

When a mixture of a cellulose ester and a solvent is heated using a non-halogen organic solvent as a solvent, the method includes a step of dissolving the cellulose ester in the solvent by one or more methods selected from the following (c) or (d) Is preferred.
(C) Swell at −10 to 55 ° C. and warm the resulting mixture to 0 to 57 ° C.
(D) Swell at −10 to 55 ° C., heat the obtained mixture to 40 to 240 ° C. at 0.2 to 30 MPa, and cool the heated mixture to 0 to 57 ° C.

[Polymer film production]
The polymer film of the present invention can be produced by the solution casting film forming method using the above polymer solution. In carrying out the solution casting film forming method, a conventional apparatus can be used in accordance with a conventional method. Specifically, the dope (polymer solution) prepared by a dissolving machine (kettle) can be filtered and then temporarily stored in a storage kettle, and the foam contained in the dope can be defoamed for final preparation. The dope is kept at 30 ° C., and is sent from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the number of rotations. It casts uniformly on the metal support body of the cast part currently cast (casting process). Next, the raw dry dope film (also referred to as a web) is peeled from the metal support at the peeling point where the metal support has almost gone around, and then transported to the drying zone, and drying is completed while being transported by a roll group. Details of the casting process and the drying process of the solution casting film forming method are also described in pages 120 to 146 of JP-A-2005-104148, and can be applied to the present invention as appropriate.

  Moreover, the polymer film of the present invention can be produced by a melt casting film forming method without using the above polymer solution. The melt casting film forming method is a method in which a polymer melted by heating is cast on a support and cooled to form a film. When the melting point of the polymer or the melting point of the mixture of the polymer and various additives is lower than the decomposition temperature and higher than the stretching temperature, a melt casting film forming method can be employed. The melt casting film forming method is described in JP-A No. 2000-352620.

  When controlling the retardation of the transparent polymer film of the present invention, it is preferable to control the mechanical history applied to the polymer film, that is, the external force applied to the polymer web in the film forming process. Specifically, when the transparent polymer film to be produced exhibits a large Re, the polymer web is preferably 0.1% or more and less than 300%, more preferably 0.5 to 200%, and even more preferably 1 to 1%. Stretch 100%.

In addition, when producing while conveying a polymer film, it is preferable to extend | stretch in the said conveyance direction. In this stretching, the residual solvent amount of the polymer web is calculated based on the following formula and is 2 to 1000%. The amount of residual solvent is preferably 10 to 200%, more preferably 30 to 150%, and still more preferably 40 to 100%.
Residual solvent amount (% by mass) = {(MN) / N} × 100
[In the formula, M represents the mass of the polymer film just before being inserted into the stretching zone, and N represents the mass when the polymer film just before being inserted into the stretching zone was dried at 110 ° C. for 3 hours.]

  If the residual solvent amount is stretched in a state of 5% or more, the haze is not easily increased. If the residual solvent amount is stretched in a state of 1000% or less, the external force applied to the polymer chain can be easily transmitted, and the above-described solvent is contained. There is a tendency that the effect of adjusting the retardation expression by stretching the polymer web is increased. The residual solvent amount of the polymer web can be appropriately adjusted by changing the concentration of the polymer solution, the temperature and speed of the metal support, the temperature and air volume of the drying air, the solvent gas concentration in the drying atmosphere, and the like. it can.

  The residual solvent amount in the dried film is preferably 0 to 2% by mass, more preferably 0 to 1% by mass, and particularly preferably 0 to 0.5% by mass. The preferred width of the polymer film is 0.5-5 m, more preferably 0.7-3 m. The preferable winding length of a film is 300-30000m, More preferably, it is 500-10000m, More preferably, it is 1000-7000m.

The formed polymer film of the present invention has a moisture permeability of 80 g in terms of film thickness, preferably 0.1 g / (m ² · day) or more, and preferably 1 to 1500 g / (m ² · day). More preferably, it is ^{2 to} 1000 g / (m ² · day), more preferably 3 to 800 g / (m ² · day). In order to make the film of the present invention have a moisture permeability of 100 g / (m ² · day) or more in terms of 80 μm, it is preferable to appropriately control the hydrophilicity / hydrophobicity of the polymer or to reduce the density of the film.

  The former method includes, for example, a method of appropriately controlling the hydrophilicity / hydrophobicity of the polymer main chain and further introducing a hydrophobic or hydrophilic side chain. The latter method includes, for example, a side chain in the polymer main chain. And the like, selection of the type of solvent used during film formation, and control of the drying rate during film formation.

The moisture permeability in the present invention refers to the change in mass before and after humidity control when a lid is sealed with a film for evaluating a cup containing calcium chloride and left for 24 hours at 40 ° C. and 90% relative humidity. g / (m ² · day)). The moisture permeability increases with increasing temperature and also increases with increasing humidity, but the magnitude relationship of moisture permeability between films is not changed regardless of the conditions.

  Therefore, in the present invention, the value of the mass change at 40 ° C. and 90% relative humidity is used as a reference. In addition, since the moisture permeability decreases as the film thickness increases and increases as the film thickness decreases, the measured moisture permeability is first multiplied by the actually measured film thickness and divided by 80 in the present invention. The water vapor transmission rate in terms of thickness of 80 μm ”.

<Polymer film>
(Optical characteristics of polymer film)
According to the production method of the present invention, a transparent polymer film with controlled retardation can be obtained. Specifically, according to the production method of the present invention, it is possible to obtain a transparent polymer film that exhibits good retardation.

(Retardation)
In this specification, Re and Rth (unit: nm) are determined according to the following method. First, the film was conditioned at 25 ° C. and 60% relative humidity for 24 hours, and then a prism coupler (MODEL2010 Prism Coupler: manufactured by Metricon) was used. An average refractive index (n) represented by (a) is obtained.
Formula (a): n = (n _TE × 2 + n _TM ) / 3
[ _Where n _TE is a refractive index measured with polarized light in the film plane direction, and n _TM is a refractive index measured with polarized light in the film surface normal direction. ]

In this specification, Re (λ) and Rth (λ) each represent in-plane retardation and retardation in the thickness direction at a wavelength λ (unit: nm). Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments).
When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (in the absence of the slow axis, any in-plane value) Measurements were made at 11 points in total by making light of wavelength λ nm incident from each inclined direction in steps of 10 ° from −50 ° to + 50 ° from the normal direction to the normal direction of the film). Then, KOBRA 21ADH or WR is calculated based on the measured retardation value, average refractive index, and input film thickness value.

  In the above, there is no description about λ, and when only Re and Rth are described, it represents a value measured using light having a wavelength of 590 nm. In addition, in the case of a film having a retardation value of zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, the retardation value at a tilt angle larger than that tilt angle. After changing its sign to negative, KOBRA 21ADH or WR calculates. In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (when there is no slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the average refractive index, and the input film thickness value, Rth can also be calculated from the following formulas (b) and (c).

[In the formula, Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction. Nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, nz represents the refractive index in the direction perpendicular to nx and ny, and d is Represents the film thickness. ]
Formula (c): Rth = ((nx + ny) / 2−nz) × d
When the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film without a so-called optical axis, Rth (λ) is calculated by the following method.

Rth (λ) is from −50 degrees to +50 degrees with respect to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH or WR) and the tilt axis (rotation axis). Measured at 11 points by making light of wavelength λ nm incident from each inclined direction in 10 degree steps, and KOBRA 21ADH or WR is calculated based on the measured retardation value, average refractive index, and input film thickness value. To do.
By inputting these average refractive index and film thickness, KOBRA 21ADH or WR calculates nx, ny, and nz. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

The polymer film of the present invention preferably has an in-plane retardation (Re) at 590 nm of 0 to 300 nm and a thickness direction retardation (Rth) of −200 to +300 nm.
Further, when the polymer film of the present invention is stretched by 3% to 400% during film formation or after film formation, the in-plane retardation (Re) is 30 to 200 nm, and the thickness direction retardation (Rth) is It is preferably −50 to +250 nm.

  In the present invention, the retardation values in the in-plane direction and the film thickness direction when the relative humidity is H (unit:%): Re (H%) and Rth (H%) are 25 ° C. and relative humidity H %, The retardation value when the measurement wavelength at RH relative to H% is 590 nm was measured and calculated in the same manner as described above at 25 ° C. and relative humidity H%.

(Humidity dependency)
The retardation value when the humidity of the polymer film of the present invention is changed preferably satisfies the following relational expression.
| Re (10%) − Re (85%) | <10 and
| Rth (10%)-Rth (85%) | <40
It is more preferable to satisfy the following relational expression.
| Re (10%) − Re (85%) | <8, and
| Rth (10%)-Rth (85%) | <35
It is more preferable to satisfy the following relational expression.
| Re (10%) − Re (85%) | <5 and
Rth (10%) − Rth (85%) | <25

(Slow axis)
In the polymer film of the present invention, the angle θ formed by the transport direction during production and the slow axis of Re of the film is preferably 0 ± 10 ° or 90 ± 10 °, and is 0 ± 5 ° or 90 ± 5 °. More preferably, 0 ± 3 ° or 90 ± 3 °, even more preferably 0 ± 1 ° or 90 ± 1 °, and most preferably 90 ± 1 °. .

(Film thickness)
The film thickness of the polymer film of the present invention is preferably 20 μm to 200 μm, more preferably 30 μm to 160 μm, and even more preferably 40 μm to 120 μm. A film thickness of 20 μm or more is preferable from the viewpoint of handling properties when processing into a polarizing plate and curling of the polarizing plate. The film thickness unevenness of the polymer film of the present invention is preferably 0 to 2% in both the transport direction and the width direction, more preferably 0 to 1.5%, and particularly preferably 0 to 1%. preferable.

(Configuration of polymer film)
The polymer film of the present invention may have a single layer structure or a plurality of layers, but preferably has a single layer structure. Here, the “single layer structure” film does not mean that a plurality of film materials are bonded together, but means a single polymer film. And it includes the case where a single polymer film is produced from a plurality of polymer solutions using a sequential casting method or a co-casting method. In this case, a polymer film having a distribution in the thickness direction can be obtained by appropriately adjusting the type and blending amount of the additive, the molecular weight distribution of the polymer, the type of polymer, and the like. Moreover, what has various functional parts, such as an optical anisotropy part, a glare-proof part, a gas barrier part, and a moisture-resistant part, in those one film is also included.

(surface treatment)
The polymer film of the present invention can be appropriately surface-treated to improve adhesion of each functional layer (for example, an undercoat layer, a back layer, and an optically anisotropic layer). The surface treatment includes glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, saponification treatment (acid saponification treatment, alkali saponification treatment), and glow discharge treatment and alkali saponification treatment are particularly preferable. The “glow discharge treatment” here is a treatment for subjecting the film surface to a plasma treatment in the presence of a plasma-excitable gas. The details of these surface treatment methods are described in the Japan Institute of Invention Disclosure Technical Bulletin (Public Technical No. 2001-1745, issued on March 15, 2001, Japan Institute of Invention) and can be used as appropriate.

  In order to improve the adhesion between the film surface and the functional layer, an undercoat layer (adhesive layer) may be provided on the transparent polymer film of the present invention in addition to or in place of the surface treatment. About the said undercoat, it describes in an invention association public technical bulletin (public technical number 2001-1745, March 15, 2001 issue, invention association) 32 pages, These can be used suitably. In addition, the functional layer provided on the cellulose ester film is described in Invention Association Public Technical Report (Public Technical Number 2001-1745, published on March 15, 2001, Invention Association), pages 32 to 45. Those described can be used on the transparent polymer film of the present invention as appropriate.

<Phase difference film>
The polymer film of the present invention can be used as a retardation film and is particularly useful. The “retardation film” is generally used for a display device such as a liquid crystal display device, and means an optical material having optical anisotropy, and is synonymous with a retardation plate, an optical compensation film, an optical compensation sheet, and the like. It is. In a liquid crystal display device, a retardation film is used for the purpose of improving the contrast of a display screen or improving viewing angle characteristics and color. By using the transparent polymer film of the present invention, a retardation film in which the Re value and the Rth value are freely controlled can be easily produced.

Further, a plurality of polymer films of the present invention can be laminated, or a polymer film of the present invention and a film outside of the present invention can be laminated to appropriately adjust Re and Rth, and used as a retardation film. Lamination of the film can be performed using a pressure-sensitive adhesive or an adhesive. In some cases, the polymer film of the present invention may be used as a support for a retardation film, and an optically anisotropic layer made of liquid crystal or the like may be provided thereon to be used as a retardation film. The optically anisotropic layer applied to the retardation film of the present invention may be formed from, for example, a composition containing a liquid crystal compound, a polymer film having birefringence, You may form from the polymer film of invention.
The liquid crystal compound is preferably a discotic liquid crystal compound or a rod-like liquid crystal compound.

(Discotic liquid crystalline compounds)
Examples of the discotic liquid crystal compound that can be used as the liquid crystal compound in the present invention include various documents (for example, C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 ( 1981); edited by The Chemical Society of Japan, Quarterly Chemical Review, No. 22, Chemistry of Liquid Crystal, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. , Page 1794 (1985); J. Zhang et.al., J. Am.Chem.Soc., Vol.116, page 2655 (1994)).

  In the optically anisotropic layer, the discotic liquid crystalline molecules are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. Further, the polymerization of discotic liquid crystalline molecules is described in JP-A-8-27284. In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Discotic liquid crystalline molecules having a polymerizable group are disclosed in JP-A No. 2001-4387.

(Bar-shaped liquid crystalline compound)
Examples of the rod-like liquid crystalline compound that can be used as the liquid crystalline compound in the present invention include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane. , Cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles. Further, as the rod-like liquid crystal compound, not only the above low molecular liquid crystal compound but also a polymer liquid crystal compound can be used.

  In the optically anisotropic layer, the rod-like liquid crystalline molecules are preferably fixed in an aligned state, and most preferably fixed by a polymerization reaction. Examples of polymerizable rod-like liquid crystalline compounds that can be used in the present invention are described in, for example, Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), U.S. Pat. Nos. 4,683,327, 5,622,648, 5,770, No. 107 specification, International Publication No. 95/22586 pamphlet, No. 95/24455 pamphlet, No. 97/00600 pamphlet, No. 98/23580 pamphlet, No. 98/52905 pamphlet, JP-A-1-272551, The compounds described in JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, JP-A-2001-328773, and the like are included.

"Polarizer"
The polymer film or retardation film of the present invention can be used as a protective film for a polarizing plate (polarizing plate of the present invention). The polarizing plate of the present invention comprises a polarizing film and two polarizing plate protective films (transparent polymer films) that protect both surfaces thereof, and the polymer film or retardation film of the present invention is used as at least one polarizing plate protective film. Can do.
When the polymer film of the present invention is used as the polarizing plate protective film, the polymer film of the present invention is hydrophilized by applying the surface treatment (also described in JP-A-6-94915 and JP-A-6-118232). For example, it is preferable to perform glow discharge treatment, corona discharge treatment, or alkali saponification treatment. In particular, when the polymer constituting the polymer film of the present invention is cellulose acylate, alkali saponification treatment is most preferably used as the surface treatment.

  As the polarizing film, for example, a film obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution can be used. When using a polarizing film obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution, the surface-treated surface of the transparent polymer film of the present invention can be directly bonded to both surfaces of the polarizing film using an adhesive. In the production method of the present invention, it is preferable that the polymer film is directly bonded to the polarizing film as described above. As the adhesive, an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral) or a latex of vinyl polymer (for example, polybutyl acrylate) can be used. A particularly preferred adhesive is an aqueous solution of fully saponified polyvinyl alcohol.

  In general, a liquid crystal display device includes four polarizing plate protective films because a liquid crystal cell is provided between two polarizing plates. The transparent polymer film of the present invention may be used for any of the four polarizing plate protective films, but the transparent polymer film of the present invention is disposed between the polarizing film and the liquid crystal layer (liquid crystal cell) in the liquid crystal display device. The protective film can be used particularly advantageously. Further, the protective film disposed on the opposite side of the transparent polymer film of the present invention across the polarizing film can be provided with a transparent hard coat layer, an antiglare layer, an antireflection layer, etc. It is preferably used as a polarizing plate protective film on the outermost surface of the display side.

<Liquid crystal display device>
The polymer film, retardation film and polarizing plate of the present invention can be used for liquid crystal display devices in various display modes. Each liquid crystal mode in which these films are used will be described below. Among these modes, the polymer film, retardation film and polarizing plate of the present invention are particularly preferably used for VA mode and IPS mode liquid crystal display devices. These liquid crystal display devices may be any of a transmissive type, a reflective type, and a transflective type.

(TN type liquid crystal display device)
The polymer film of the present invention may be used as a support for a retardation film of a TN type liquid crystal display device having a TN mode liquid crystal cell. TN mode liquid crystal cells and TN type liquid crystal display devices have been well known for a long time. Regarding the retardation film used in the TN type liquid crystal display device, each of JP-A-3-9325, JP-A-6-148429, JP-A-8-50206, and JP-A-9-26572, and Mori. It is described in other papers (Jpn. J. Appl. Phys. Vol. 36 (1997) p. 143 and Jpn. J. Appl. Phys. Vol. 36 (1997) p. 1068).

(STN type liquid crystal display device)
The polymer film of the present invention may be used as a support for a retardation film of an STN type liquid crystal display device having an STN mode liquid crystal cell. In general, in a STN type liquid crystal display device, rod-like liquid crystalline molecules in a liquid crystal cell are twisted in the range of 90 to 360 degrees, and the refractive index anisotropy (Δn) and cell gap (d) of the rod-like liquid crystalline molecules. Product (Δnd) is in the range of 300-1500 nm. The retardation film used in the STN type liquid crystal display device is described in JP-A No. 2000-105316.

(VA type liquid crystal display device)
The polymer film of the present invention is particularly advantageously used as a retardation film or a support for a retardation film in a VA liquid crystal display device having a VA mode liquid crystal cell. The VA-type liquid crystal display device may be an alignment-divided system as described in, for example, JP-A-10-123576. In these embodiments, the polarizing plate using the polymer film of the present invention contributes to widening the viewing angle and improving the contrast.

(IPS liquid crystal display device and ECB liquid crystal display device)
The polymer film of the present invention is particularly advantageous as a retardation film, a retardation film support or a protective film for a polarizing plate of an IPS liquid crystal display device and an ECB liquid crystal display device having IPS mode and ECB mode liquid crystal cells. Used. In these modes, the liquid crystal material is aligned substantially in parallel during black display, and black is displayed by aligning liquid crystal molecules parallel to the substrate surface in the absence of voltage. In these embodiments, the polarizing plate using the polymer film of the present invention contributes to widening the viewing angle and improving the contrast.

(OCB type liquid crystal display device and HAN type liquid crystal display device)
The polymer film of the present invention is also advantageously used as a support for a retardation film of an OCB type liquid crystal display device having an OCB mode liquid crystal cell or a HAN type liquid crystal display device having a HAN mode liquid crystal cell. In the retardation film used for the OCB type liquid crystal display device or the HAN type liquid crystal display device, it is preferable that the direction in which the absolute value of retardation is minimum does not exist in the plane of the retardation film and in the normal direction. The optical properties of the retardation film used in the OCB type liquid crystal display device or the HAN type liquid crystal display device are also the optical properties of the optical anisotropic layer, the optical properties of the support, and the optical anisotropic layer and the support. Determined by placement. A retardation film used for an OCB type liquid crystal display device or a HAN type liquid crystal display device is described in JP-A-9-197397. Further, it is described in a paper by Mori et al. (Jpn. J. Appl. Phys. Vol. 38 (1999) p. 2837).

(Reflective liquid crystal display)
The polymer film of the present invention is also advantageously used as a retardation film of a reflective liquid crystal display device of TN type, STN type, HAN type, and GH (Guest-Host) type. These display modes have been well known since ancient times. The TN type reflective liquid crystal display device is described in JP-A-10-123478, WO98 / 48320 pamphlet, and Japanese Patent No. 3022477. The retardation film used in the reflective liquid crystal display device is described in International Publication No. 00/65384 pamphlet.

(Other liquid crystal display devices)
The polymer film of the present invention is also advantageously used as a support for a retardation film of an ASM type liquid crystal display device having a liquid crystal cell in an ASM (Axial Symmetrical Microcell) mode. The ASM mode liquid crystal cell is characterized in that the thickness of the cell is maintained by a resin spacer whose position can be adjusted. Other properties are the same as those of the TN mode liquid crystal cell. The ASM mode liquid crystal cell and the ASM type liquid crystal display device are described in a paper by Kume et al. (Kume et al., SID 98 Digest 1089 (1998)).

(Hard coat film, antiglare film, antireflection film)
In some cases, the polymer film of the present invention may be applied to a hard coat film, an antiglare film, and an antireflection film. For the purpose of improving the visibility of flat panel displays such as LCD, PDP, CRT, EL, etc., any or all of a hard coat layer, an antiglare layer and an antireflection layer are provided on one or both sides of the transparent polymer film of the present invention. can do. Preferred embodiments of such an antiglare film and antireflection film are described in detail on pages 54 to 57 of the Japan Institute of Invention and Technology (Publication No. 2001-1745, published on March 15, 2001, Japan Society of Invention). It can be preferably used also in the polymer film of the present invention.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.
In addition, the measurement method and evaluation method of the characteristic used in the Example are as follows.

(Degree of substitution)
The acyl substitution degree of the cellulose ester is determined by Carbohydr. Res. Was determined by ¹³ C-NMR according to the method described in 273 (1995) 83-91 (Tezuka et al.).

(Glass transition temperature Tg)
20 mg of a sample was placed in a measurement pan of DSC (manufactured by SII Nano Technology). This was heated to 30 ° C. to 250 ° C. at 10 ° C./min in a nitrogen stream and then cooled to 30 ° C. at −10 ° C./min. Thereafter, the temperature was raised again to 30 ° C. to 250 ° C., and the temperature at which the baseline began to deviate from the low temperature side was defined as Tg.

(Weight average molecular weight, number average molecular weight)
The resin sample was dissolved in THF to prepare a 0.5% by mass sample solution, and the weight average molecular weight and number average molecular weight were measured using GPC under the following conditions. The calibration curve was prepared using polystyrene (TSK standard polystyrene: molecular weight 1050, 5970, 18100, 37900, 190000, 706000). As the column, TSK GEL Super HZ4000, TSK GEL Super HZ2000, TSK GEL Super HZM-M, and TSK Guard Column Super HZ-L (all manufactured by Tosoh Corporation) were used. The column temperature was 40 ° C., THF was used as an eluent, the flow rate was 1 ml / min, and a refractometer (RI) was used as a detector.

(Retardation)
5 points in the width direction (center part, end part (position of 5% of the total width from each end), and two intermediate parts between the center part and the end part) are sampled every 100 m in the longitudinal direction, and the size is 2 cm □ Samples were taken out and the average value of each of the retardation values evaluated according to the above-mentioned method was determined. Re, Rth, Re (10%), Re (85%), Rth (10%), Rth (85%) And ΔRe and ΔRth were calculated from the following formulas (VIII) and (IX). The retardation was measured at λ = 590 nm.
Formula (VIII): ΔRe = | Re (10%) − Re (85%) |
Formula (IX): ΔRth = | Rth (10%) − Rth (85%) |

[Slow axis variation]
The maximum value of the deviation from the transport direction or the direction orthogonal to the direction of the slow axis of each sample taken in the same manner as in the above-described retardation measurement (unit: can take values of °, −45 to + 45 °). And the difference between the minimum values and the slow axis variation.

(Degree of polarization)
According to the preparation and evaluation of the polarizing plate described in [Example 7] described later, the transmittance (Tp) and the absorption axis when two polarizing plates prepared from the respective films are superposed in parallel with the absorption axis. The transmittance (Tc) in the case of being overlapped at right angles was measured, and the degree of polarization (P) represented by the following formula was calculated.
Polarization degree P = ((Tp−Tc) / (Tp + Tc)) ^0.5
Here, the transmittance was calculated by the following method.
The transmittance was measured with a Shimadzu spectrophotometer UV-3100PC, and calculated according to the following formula from the spectral transmittance τ (λ) obtained every 10 nm. In the equation, P (λ) is the spectral distribution of the standard light C light source, and y (λ) is a color matching function based on the two-degree field of view X, Y, Z system.

(Polarizing plate durability)
The two polarizing plates obtained above were aged at 60 ° C. and 90% RH for 500 hours, the two were orthogonally crossed (crossed Nicols), and the increase in transmittance from the initial stage was evaluated. The larger the number, the worse the polarizing plate durability over time.

(Moisture permeability)
Moisture permeability is the change in mass before and after humidity control (g / () when a cup containing calcium chloride covered with a film sample and sealed for 24 hours at 60 ° C. and 95% relative humidity. m ² · day)).

(Film surface)
The surface of the transparent polymer film was visually observed and evaluated according to the following evaluation scale.
A: The film has a good surface shape and can be preferably applied as an optical film.
B: Although slight undulation is confirmed in the film, it can be preferably applied as an optical film.
C: The film has a swell over a considerable area or is partially cloudy and cannot be applied as an optical film.
D: Remarkable undulation occurs in the film, or the entire surface is cloudy, and cannot be applied as an optical film.

(Dimension)
A 30mm x 120mm sample was conditioned at 40 ° C, 95% RH, 60 ° C, and 90% RH for 24 hours, respectively. The original size (L1) of the gap was measured to a minimum scale of 1/1000 mm. Furthermore, heat treatment was performed at 90 ° C. and 5% RH for 24 hours and 120 hours, and the dimension (L2) of the punch interval was measured. And it calculated | required by dimension = {(L1-L2) / L1} * 100.

(Film durability)
A sample 30 mm × 120 mm was aged for 1500 hours at 60 ° C. and 95% RH, respectively, and the state of the film was visually observed at 25 ° C. The film durability was judged according to the following evaluation criteria.
A: No abnormality was observed in the film.
B: Slight cracks were observed at the film edge.
C: The film was considerably cracked.
D: Cracks on the entire surface were observed on the film.

(Haze)
The film was sampled at 5 points in the width direction (the central part and the end part of the film (positions of 5% of the total width from both ends) and the middle part between the central part and the end part) and evaluated according to JIS-K7136. The average value of each point was calculated to determine the haze value. A haze meter (HGM-2DP, Suga test machine) was used as a measuring instrument.

[Example 1: Production and evaluation of transparent polymer film P101-130]
(1) Preparation of polymer solution (polymer)
In the production of each film, cellulose esters described in Table 1 were used as polymers. Each polymer was heated to 110 ° C. and dried to adjust the water content to 0.5% by mass or less, and then 20 parts by mass was used.
The moisture content was measured by a Karl Fischer method using a polymer film sample 7 mm × 35 mm with a moisture meter and a sample drying apparatus (CA-03, VA-05, both Mitsubishi Chemical Corporation). It was calculated by dividing the amount of water (g) by the sample mass (g).

(solvent)
In the production of each film, a mixed solvent of dichloromethane / methanol / butanol (80/19/1 part by mass) was used. The water content of the solvent was 0.2% by mass or less.

(Preparation of polymer solution (hereinafter sometimes referred to as dope))
The above-mentioned solvent is mixed in a 4000 L volume stainless steel dissolution tank having a stirring blade to form a mixed solvent, and various additives (described later) may be added and stirred and dispersed, followed by polymer A (cellulose triacetate- described below). A) was gradually added, and the whole was adjusted to 2000 kg. In addition, all the solvents used that the water content is 0.2 mass% or less. Polymer powder is put into a dispersion tank, a dissolver type eccentric stirring shaft is rotated at a peripheral speed of 5 m / sec (shear stress 5 × 10 ⁴ kgf / m / sec ² ), and an anchor blade is provided on the central axis. The shaft was dispersed for 30 minutes while being stirred at a peripheral speed of 1 m / sec (shear stress 1 × 10 ⁴ kgf / m / sec ² ). The starting temperature of dispersion was 20 ° C., and the final temperature reached 35 ° C. After completion of the dispersion, the high-speed stirring was stopped, the peripheral speed of the anchor blade was set to 0.5 m / sec, and stirring was further performed for 100 minutes to swell the polymer flakes. Until the end of swelling, the inside of the tank was pressurized to 0.12 MPa with nitrogen gas. At this time, the oxygen concentration in the tank was less than 2 vol%, and the state of no problem was maintained in terms of explosion protection. Further, it was confirmed that the water content in the dope was 0.5% by mass or less (0.3% by mass).
The concentration of polymer A was 20% by mass.

The used polymer A (also referred to as cellulose triacetate-A or cellulose ester A) has a substitution degree of 2.85, a viscosity average polymerization degree of 305, a water content of 0.15% by mass, a viscosity of 295 mPa · s of 6% by mass in a methylene chloride solution, A powder having an average particle diameter of 1.5 mm and a standard deviation of 0.5 mm, the amount of residual acetic acid is 0.01% by mass or less, Ca is 0.001% by mass, and Mg is 0.004% by mass. Yes, K was 2 ppm, Na was 1 ppm, Fe was 0.5 ppm, and sulfur (present as a sulfate group) was 22 ppm. The number average molecular weight (Mn) was 91,000, the weight average molecular weight (Mw) was 273,000, and Mw / Mn was 3.1. Further, the substitution degree of the 6-position acetyl group was 0.95, which was 33.3% of the total acetyl groups. The acetone extract was 8% by mass, the ratio of the weight average molecular weight to the number average molecular weight was 3.1, and the distribution was uniform. The yellowness index of a film having a thickness of 80 μm prepared using dichloromethane / methanol (90/10 parts by mass) is 0.3, the haze is 0.08, the transmittance is 93.5%, and Tg is At 163 ° C., the crystallization exotherm was 6.8 J / g. The repose angle was 35 degrees, the bulk density was 0.55 g / cm ³ , the tap density was 0.63 g / cm ³ , and the compressibility was 13%. Furthermore, 20 kg of a solution in which cellulose ester A was dissolved in a mixed solvent of methylene chloride / methanol (92/8 and 80/20 mass ratio) at room temperature (25 ° C.), an average diameter of 10 μm, a diameter of 10 cm, a thickness After passing through a 1 mm cellulose ester filter paper, the filter paper was thoroughly washed with each solvent and the increased mass of the SUS filter was measured. The mass increase rate was methylene chloride / methanol (92/8 mass ratio). Was 0.05%, and in the case of methylene chloride / methanol (80/20 mass ratio), it was 0.09%. Here, the evaluation was as follows. The angle of repose was determined by measuring the angle formed by the conical hypotenuse formed by pouring through a funnel on a disk having a diameter of 8 cm and the horizontal. The bulk density (A) before tapping was measured with a cylinder capacity of 100 cm ³ using a Seisen company tap denser KYT-4000. Moreover, the tap density measured the bulk density (P) at the time of 10 mm of strokes and 200 times of taps using the cylinder capacity of 100 cm < ³ > using the tap denser KYT-4000 made from a Seishin company. Furthermore, the degree of compression was calculated from the values of the bulk densities A and P obtained above as (PA) / P × 100 (unit:%).
The cellulose esters B to E are described later.

(Additive)
Plasticizer: Types and contents thereof are shown in Table 1 (mass% based on cellulose ester or cyclic polyolefin, and the high molecular weight plasticizer of the present invention used here had a molecular weight of 500 or less of components of 10 mass% or less. .)
UV absorber a: 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine 0.4 parts by mass (cellulose ester) Or mass% based on cyclic polyolefin)
UV absorber b: ADK STAB LA-31 (ADEKA product) 0.4 parts by mass (mass% based on cellulose ester or cyclic polyolefin)

UV absorber c: 0.4 part by mass of 2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole (mass% based on cellulose ester or cyclic polyolefin)
_{C 12 H 25 OCH 2 CH 2} O-P (= O) - (OK) 2 ( releasing agent): 0.02 parts by mass (mass% with respect to the cellulose ester or a cyclic polyolefin)
Citric acid monoethyl ester and citric acid diethyl ester mixture (release agent): 0.02 parts by mass (mass% based on cellulose ester or cyclic polyolefin)
Fine particles: silicon dioxide (particle size 20 nm, Mohs hardness about 7) 0.05 parts by mass (mass% based on cellulose ester or cyclic polyolefin)

(Dissolution / filtration process)
The swollen solution was heated from the tank to 50 ° C. with a jacketed pipe and further heated to 90 ° C. under a pressure of 1.2 MPa to be completely dissolved. The heating time was 15 minutes. Next, the temperature was lowered to 36 ° C., and a dope was obtained by passing through a filter medium having a nominal pore diameter of 8 μm. At this time, the primary pressure of filtration was 1.3 MPa, and the secondary pressure was 1.0 MPa. Filters, housings, and pipes that were exposed to high temperatures were made of Hastelloy (registered trademark) and had excellent corrosion resistance, and those having a jacket through which a heat medium for heat retention and heating was distributed.

(Concentration / filtration)
The pre-concentration dope thus obtained was flushed at 80 ° C. in a normal pressure tank, and the evaporated solvent was recovered and separated by a condenser. The solid concentration of the dope after flashing was 24.8% by mass. The condensed solvent was sent to a recovery process to be reused as a solvent in the preparation process (recovery is carried out by a distillation process, a dehydration process, etc.). In the flash tank, defoaming was performed by stirring a shaft having an anchor blade on the central shaft at a peripheral speed of 0.5 m / sec. The temperature of the dope in the tank was 25 ° C., and the average residence time in the tank was 50 minutes.

  Next, bubble removal was performed by irradiating the dope with weak ultrasonic waves. Thereafter, under a pressure of 1.3 MPa, first, a sintered fiber metal filter having a nominal pore diameter of 10 μm was passed, and then a sintered fiber filter having a same pore size of 10 μm was passed. Respective primary pressures were 1.4 MPa and 1.1 MPa, and secondary pressures were 1.0 MPa and 0.7 MPa. The dope temperature after filtration was adjusted to 36 ° C. and stored in a 2000 L stainless steel stock tank. In the stock tank, stirring was performed by constantly rotating a shaft having an anchor blade on the central shaft at a peripheral speed of 0.3 m / sec. In addition, when the dope was prepared from the dope before concentration, no problem such as corrosion occurred at all in the wetted part of the dope.

(2) Film production (casting process)
Subsequently, the dope in the stock tank was fed by a feedback control using an inverter motor so that the primary pressure of the high precision gear pump became 0.8 MPa with a gear pump for primary pressure increase. The high precision gear pump had a volumetric efficiency of 99.3% and a discharge rate variation of 0.4% or less. Moreover, the discharge pressure was 1.4 MPa.

  The casting die is 1.6m in width and is equipped with a feed block adjusted for co-casting. In addition to the mainstream, a device that can be laminated on both sides to form a three-layer film is used. It was. In the following description, a layer formed from the mainstream is referred to as an intermediate layer, a support surface side layer is referred to as a support surface, and an opposite surface is referred to as an air surface. In addition, the dope liquid supply flow path used three flow paths for the intermediate layer, the support surface, and the air surface. In the production of this film, only the flow path for the intermediate layer was used.

Then, casting was performed by adjusting the flow rate of the polymer dope at the die protrusion so that the film thickness of the completed polymer film was 80 μm. In order to adjust the dope temperature to 36 ° C., a jacket was provided on the casting die, and the inlet temperature of the heat transfer medium supplied into the jacket was set to 36 ° C.
The die, feed block, and piping were all kept at 36 ° C. during the work process. The die was a coat hanger type die, with thickness adjusting bolts provided at a pitch of 20 mm, and having an automatic thickness adjusting mechanism using a heat bolt. This heat bolt can also set a profile according to the liquid feed amount of the high precision gear pump by a preset program, and feedback control can also be performed by an adjustment program based on the profile of the infrared thickness gauge installed in the film forming process It has performance. The thickness difference between any two points 50 mm apart in the film excluding the casting edge portion 20 mm was within 1 μm, and the largest difference in the width direction thickness was adjusted to 2 μm / m or less. In addition, a chamber for decompressing was installed on the primary side of the die. The degree of decompression of the decompression chamber can apply a pressure difference of 1 Pa to 5000 Pa before and after the casting bead, and can be adjusted according to the casting speed. At that time, the pressure difference was set such that the bead length was 2 mm to 50 mm.

(Casting die)
The material of the die is a duplex stainless steel having a mixed composition of austenite phase and ferrite phase, a material having a thermal expansion coefficient of 2 × 10 ⁻⁵ (° C. ⁻¹ ) or less, and a forced corrosion test in an aqueous electrolyte solution. A material having corrosion resistance substantially equivalent to that of SUS316 was used. The finishing precision of the wetted surfaces of the casting die and the feed block is 1 μm or less in surface roughness, the straightness is 1 μm / m or less in any direction, and the clearance of the slit is 0.5 mm to 3.3 by automatic adjustment. It was adjustable up to 5 mm. The production of this film was performed at 1.5 mm. About the corner | angular part of the liquid-contact part of die-die tip, it processed so that R might be set to 50 micrometers or less over the slit full width. The shear rate inside the die was in the range of 1 (sec ⁻¹ ) to 5000 (sec ⁻¹ ).

Further, a casting die provided with a cured film was used at the lip tip. There are tungsten carbide (WC), Al ₂ O ₃ , TiN, Cr ₂ O _{3 and the} like, and particularly preferred is WC. In the present invention, a WC coating formed by thermal spraying is used. Further, a mixed solvent (dichloromethane / methanol / butanol (83/15/2 parts by mass)) which is a solvent for solubilizing the dope was supplied to the gas-liquid interface between the bead end and the slit at 0.5 ml / min on one side. Furthermore, in order to make the temperature of the decompression chamber constant, a jacket was attached and a heat transfer medium adjusted to 35 ° C. was supplied. The edge suction air volume was adjusted in the range of 1 L / min to 100 L / min, and was adjusted appropriately in the range of 30 L / min to 40 L / min in the production of this film.

(Metal support)
A stainless steel endless band having a length of 100 m was used as a support. The thickness of the band was 1.5 mm, the surface roughness was polished to 0.05 μm or less, the material was made of SUS316, and it had sufficient corrosion resistance and strength. The thickness unevenness of the entire band was 0.5% or less. The band is a type driven by two drums, and the tension of the band at that time is adjusted to 1.5 × 10 ⁴ kg / m, and the relative speed difference between the band and the drum is 0.01 m / min or less. Met. The band drive speed fluctuation was 0.5% or less. In addition, the meandering in the width direction of one rotation was controlled by detecting the positions of both ends of the band so as to be limited to 1.5 mm or less. Further, the positional fluctuation in the vertical direction accompanying the drum rotation on the support surface just below the casting die was set to 200 μm or less. The support is installed in a casing having wind pressure vibration suppression means. A dope was cast on the support from a die. The surface temperature of the central part of the support just before casting was 15 ° C. The temperature difference between both ends was 6 ° C. or less. There should be no surface defects on the metal support, no pinholes of 30 μm or more, 1 pinholes of 10 μm to 30 μm / m ² or less, ² pinholes of 10 μm or less / m ² The following support was used.

(Casting drying)
The temperature of the casting chamber provided with the casting die and the support was kept at 35 ° C. The dope cast on the band was first dried by sending parallel-flow drying air. The overall heat transfer coefficient from the drying air to the dope during drying was 24 kcal / m ² · hr · ° C. The temperature of the drying air was 130 ° C on the upstream side of the upper part of the band, and 135 ° C on the downstream side. The lower part of the band was set to 65 ° C. The saturation temperature of each gas was around -8 ° C. The oxygen concentration in the dry atmosphere on the support was kept at 5 vol%. Note that the air was replaced with nitrogen gas in order to maintain the oxygen concentration at 5 vol%. Moreover, in order to condense and collect the solvent in the casting chamber, a condenser (condenser) was provided, and the outlet temperature was set to −10 ° C.

For 5 seconds after casting, the static pressure fluctuation in the immediate vicinity of the casting die was suppressed to ± 1 Pa or less so that the dry wind did not directly hit the dope with a wind shield. When the solvent ratio in the dope became 45% by mass on a dry basis, the film was peeled off from the casting support. The peeling tension at this time was 8 kgf / m, and the peeling speed (peeling roll draw) with respect to the support speed was set so as to be properly peeled in the range of 100.1% to 110%. The surface temperature of the peeled film was 14 ° C. The drying speed on the support was 62% by mass on the basis of dry weight based solvent / min. The solvent gas generated upon drying was led to a condenser, liquefied at -10 ° C, recovered and reused as a charging solvent. The drying air from which the solvent was removed was heated again and reused as drying air. At that time, the water content in the solvent was adjusted to 0.5% or less and reused.
The peeled film was conveyed by the transfer part provided with many rollers. The transition part was equipped with three rollers, and the temperature of the transition part was kept at 40 ° C. During conveyance with the roller at the crossing part, a tension of 16N to 160N was applied to the film.

(Tenter transport / drying process conditions)
The peeled film was conveyed in the drying zone of the tenter while being fixed at both ends with a tenter having a clip, and dried with drying air. The clip was cooled by supplying a heat transfer medium at 20 ° C. The tenter was driven by a chain, and the speed fluctuation of the sprocket was 0.5% or less. Further, the inside of the tenter was divided into three zones, and the drying air temperature of each zone was set to 90 ° C., 100 ° C., and 110 ° C. from the upstream side. The gas composition of the drying air was set to a saturated gas concentration of −10 ° C. The average drying rate in the tenter was 120% by mass (dry weight reference solvent) / min. At the exit of the tenter, the amount of residual solvent in the film was adjusted to 10% by mass or less, and in the production of this film, the conditions of the drying zone were adjusted to 7% by mass. In the tenter, the film was stretched in the width direction while being conveyed. The amount of widening when the width when conveyed to the tenter was 100% was 103%. The stretching ratio from the peeling roller to the tenter inlet (tenter driven draw) was 102%. As for the stretching ratio in the tenter, the difference in the actual stretching ratio at a portion 10 mm or more away from the tenter biting portion was 10% or less, and the stretching ratio difference at any two points 20 mm apart was 5% or less.

The ratio of the length of the base end fixed by the tenter was 90%. Further, the tenter clip was transported while being cooled so as not to exceed 50 ° C. The solvent evaporated in the tenter part was condensed at a temperature of −10 ° C., liquefied and recovered. A condenser (condenser) was provided for condensation recovery, and the outlet temperature was set to -8 ° C. The water contained in the solvent was adjusted to 0.5% by mass or less and reused.
Then, the ears were cut at both ends within 30 seconds from the tenter exit. Ears 50 mm on both sides were cut with an NT type cutter. The oxygen concentration in the dry atmosphere of the tenter part was kept at 5 vol%. Note that the air was replaced with nitrogen gas in order to maintain the oxygen concentration at 5 vol%. The film was preheated in a predrying zone supplied with 100 ° C. drying air before being dried at a high temperature in a roller conveyance zone described later.

(Post-drying process conditions)
The trimmed polymer film obtained by the above-described method was dried at high temperature in a roller conveyance zone. The roller conveyance zone was divided into four sections, and drying air of 120 ° C., 130 ° C., 130 ° C., and 130 ° C. was supplied from the upstream side. At this time, the roller conveying tension of the film was set to 100 N / width, and the film was dried for about 10 minutes until the residual solvent amount finally reached 0.3% by mass. The wrap angle of the roller was 90 degrees and 180 degrees. The roller was made of aluminum or carbon steel, and a hard chrome plating was applied to the surface. As the surface shape of the roller, a flat one and a mat formed by blasting were used. All the shakes due to the rotation of the roller were 50 μm or less. The roller deflection at a tension of 100 N / width was selected to be 0.5 mm or less.

A forced charge removal device (charge removal bar) was installed during the process so that the film voltage during conveyance was always in the range of -3 kV to 3 kV. Moreover, in the winding part, not only the charge removal bar but also ion wind charge removal was installed so that the charge would be -1.5 kV to 1.5 kV.
The dried film was conveyed to the 1st humidity control chamber. A drying air of 110 ° C. was supplied to the transition part between the roller conveyance zone and the first humidity control chamber. The first humidity chamber was supplied with air having a temperature of 50 ° C. and a dew point of 20 ° C. Further, the film was conveyed to a second humidity control chamber that suppresses the curling of the film. In the second humidity control chamber, air of 90 ° C. and humidity 70% was directly applied to the film.

(Post-processing and winding conditions)
The polymer film after drying was cooled to 30 ° C. or lower and cut off at both ends. For the edge-cutting, two devices for slitting the film edge were installed on the left and right ends of the film (two slit devices per side), and the film edge was slit. Here, the slitting device is composed of a disk-shaped rotating upper blade and a roll-shaped rotating lower blade, the material of the rotating upper blade is a super steel material, the diameter of the rotating upper blade is 200 mm, and cutting The thickness of the blade at the place was 0.5 mm. The material of the roll-shaped rotary lower blade was a super steel material, and the roll diameter of the rotary lower blade was 100 mm.

And when the surface roughness (arithmetic mean roughness: Ra) of the cross section of the slit film was measured, it was 0.2 micrometer. The slit film cross section was relatively smooth and free from chips. Further, in the film formation of the cellulose ester film, there was no breakage of the film during transportation.
Here, the surface roughness of the film cross section was measured using a surface roughness measuring device (NewView 5010) manufactured by ZYGO under the conditions of the objective lens 50 times and the image zoom 1.3 times. In this case, the measurement conditions were set as appropriate with the Measurement Ctrl key, and the measured data was subjected to data processing with the Analyze Control key set as appropriate.

Thus, a cellulose ester film having a width of 1500 mm and a film thickness of 80 μm was obtained and wound up by a winder. Moreover, the dimensional change rate of the location 20 mm wide from the film edge part of the slit cellulose-ester film was measured. Here, the dimensional change rate was evaluated by measuring the dimension (width) after holding for 120 hours in an environment of a temperature of 90 ° C. and a relative humidity of 5% with respect to the dimension immediately after production of the cellulose ester film (length in the width direction). Evaluation was made by taking the percentage of the length in the hand direction. As a result, the dimensional change rate at a portion 20 mm wide from the end of the cellulose ester film was −0.13%, and there was no problem.
Further, knurling was performed on both ends of the film. The knurling was applied by embossing from one side, the knurling width was 10 mm, and the pressing pressure was set so that the maximum height was 12 μm higher than the average thickness on average.

  And the film was conveyed to the winding chamber. The winding chamber was kept at a room temperature of 25 ° C. and a humidity of 60%. The product width of the polymer film thus obtained was 1500 mm. The tension pattern was such that the diameter of the winding core was 169 mm, the winding start tension was 390 N / width, and the winding end was 250 N / width. The total winding length was 3250 m. The oscillating period during winding was 400 m, and the oscillating width was ± 5 mm. Moreover, the pressing pressure of the press roll with respect to the winding roll was set to 50 N / width. The temperature of the film at the time of winding was 25 ° C., the water content was 0.8% by mass, and the residual solvent amount was 0.2% by mass. The average drying rate was 20% by mass (dry weight reference solvent) / min throughout the entire process. Moreover, there was no winding looseness and wrinkles, and no winding slip occurred in the impact test at 10G. The roll appearance was also good. A polymer film sample was formed through the above steps. The film sample rolls were stored in a storage rack at 25 ° C. and 55% relative humidity for 1 month and further examined in the same manner as described above. As a result, no significant change was observed. Further, no adhesion was observed in the roll. Moreover, after film-forming of the film sample, the peeling remainder of the cast film formed from dope was not seen at all on the endless belt which is a metal support body.

(3) Evaluation of polymer film Each polymer film produced was evaluated from various viewpoints shown below, and the results are shown in Table 1.

(Evaluation of roll dirt)
A: No dirt substance was observed on the metal support.
B: Dirt substance was slightly recognized on the metal support.
C: A considerable amount of dirt was observed on the metal support.
D: On the entire surface of the metal support, a dirt substance was observed.

(Evaluation of ear-opening state)
A: The edge cut width was within 200 mm, and no flaws were found on the edge cut edge portion of the film magnified 5 times with a magnifying glass.
B: The edge cut width was within 200 mm, and small scratches were observed at the edge cut edge portion of the film magnified 5 times with a loupe.
C: The edge cut width was 250 mm or more, and small scratches were observed at the edge cut edge portion of the film magnified 5 times with a loupe.
D: The edge cut width was 250 mm or more, and many scratches were observed at the edge cut edge portion of the film magnified 5 times with a magnifier.

(Evaluation of heated crying)
A 10 cm square film was conditioned for 2 hours in an environment of 25 ° C. and 60% RH, and then heated in a thermostatic bath at 230 ° C. for 10 minutes. The heated film was taken out and allowed to stand in an environment of 25 ° C. and 60% RH for 2 hours, and then the state of the film surface was visually observed.
A: No crying substance was seen on the film surface.
B: Slightly crying material was observed on the film surface.
C: A considerable amount of crying material was observed on the film surface.
D: On the entire surface of the film, crying material was seen.

  As shown in Table 1, the comparative film P101 that does not use a plasticizer is inferior in the edge-cut state, moisture permeability, and dimensions, extremely poor in polarizing plate durability, and greatly deteriorated as an optical film. Furthermore, the comparative film P102 to the comparative film P105 to which only one of the aliphatic polymer plasticizer and the aromatic polymer plasticizer according to the present invention is added are similarly inferior in dimension and polarizing plate durability. Therefore, the object of the present invention could not be achieved. In addition, the comparative films P116 to P119 using the comparative plasticizers A and B used for general polymers that are low molecular plasticizers satisfy all of roll dirt, heat crying, and film durability. could not. Further, the comparative films P120 to P122 which are aromatic high molecular weight plasticizers but have a small molecular weight are poor in roll dirt and heat crying and cannot be used as optical films. Furthermore, although it is an aliphatic high molecular weight plasticizer or an aromatic high molecular weight plasticizer, its number average molecular weight is small, and films P123 to 126 using comparative plasticizers D, E, and F that are outside the scope of the present invention. Was not able to satisfy all of the surface condition, roll dirt, and heat crying. On the other hand, although it is an aliphatic high molecular weight plasticizer, the film P127 using the comparative plasticizer G, which has a large number average molecular weight and is outside the scope of the present invention, is also planar, roll soiled, ear cut, dimension, etc. Could not be satisfied. Moreover, although the aliphatic high molecular weight plasticizer and the aromatic high molecular weight plasticizer of the present invention are used, the films P128 and P129 whose mixing ratio is out of the scope of the present invention have dimensions, polarizing plate durability. Therefore, it was judged to be a practically problematic level. Further, although the aliphatic high molecular weight plasticizer and the aromatic high molecular weight plasticizer of the present invention are used, the film P130 whose addition amount is outside the scope of the present invention is problematic in terms of characteristics. there were. On the other hand, the film P106 to the film P115 of the present invention satisfy all of the surface shape, roll dirt, ear cut state, haze, moisture permeability, size, heat crying and film durability, and are for optical use. It was excellent as a film. Furthermore, the films of the present invention all had a slow axis variation of 0.2 ° or less, which was an excellent slow axis variation level. The films of the present invention all have ΔRe of 8 nm or less and all of ΔRth of 35 nm or less, which are practically satisfactory.

Table 2 below shows the number average molecular weight of each plasticizer and the value of loss on heating (%) at 140 ° C. for 60 minutes. In addition, a heating loss is calculated | required by a following formula.
Loss on heating (%) = {(mass before heating) − (mass after heating)} / (mass before heating) × 100
The plasticizer in the present invention has a loss on heating of less than 1%, and it can be seen that process contamination during production can be reduced.

[Example 2: Production and evaluation of transparent polymer film P201-204]
Polymer films P201 to 204 of the present invention were produced in exactly the same manner as the production of the polymer film P106 in Example 1 except that the cellulose ester A was changed to cellulose esters B to E. As described in Table 1, these films satisfy all of roll dirt, ear cut-off state, and heat crying, and are Rth humidity dependency (ΔRth) is small, and are optical films having excellent characteristics. It was.
Here, the cellulose esters B to E are described below.

Cellulose ester B is cellulose triacetate, having a substitution degree of 2.49, a viscosity average polymerization degree of 280, a water content of 0.2% by mass, a viscosity of 260 mPa · s of 6% by mass in methylene chloride solution, and an average particle size of 1.5 mm. Powder having a standard deviation of 0.4 mm, residual acetic acid amount of 0.02% by mass or less, Ca 5 ppm, Mg 40 ppm, K 3 ppm, Na 2 ppm, Fe 0.5 ppm, sulfur (as sulfate group) Existence) was 29 ppm, K was 11 ppm, Na was 5 ppm, and Fe was 0.4 ppm. The number average molecular weight (Mn) was 84,000, the weight average molecular weight (Mw) was 238,000, and Mw / Mn was 2.8. Further, the substitution degree of the 6-position acetyl group is 0.85, and the sum of the substitution degrees at the 6-position is 34% of the total acetyl, the yellowness index is 0.4, the haze is 0.07, the transparency is 92.7%, The Tg was 152 ° C. and the crystallization exotherm was 3.1 J / g. Further, it had physical properties of an angle of repose of 38 degrees, a bulk density of 0.55 g / cm ³ , a tap density of 0.60 g / cm ³ , and a compressibility of 8%. Furthermore, 20 kg of a solution in which cellulose ester B is dissolved in a mixed solvent of methylene chloride / methanol (92/8 and 80/20 mass ratio) at room temperature (25 ° C.) is a filter paper having an average diameter of 10 μm and a thickness of 1 mm. Then, the filter paper was thoroughly washed with each solvent and the increased mass of the SUS filter was measured. The mass increase rate was 0.05% in the case of methylene chloride / methanol (92/8 mass ratio). Yes, in the case of methylene chloride / methanol (80/20 mass ratio), it was 0.09%.

Cellulose ester C is cellulose acetate propionate, acetyl substitution degree 1.90, propionate substitution degree 0.75, total substitution degree 2.65, viscosity average polymerization degree 260, water content 0.1 mass%, methylene chloride Powder having a viscosity of 245 mPa · s, an average particle diameter of 0.9 mm, and a standard deviation of 0.4 mm, a residual acetic acid amount of 80 ppm and a propionic acid amount of 70 ppm, Ca of 12 ppm, Mg of 50 ppm, K is 3 ppm, Na is 2 ppm, Fe is 2 ppm, Sulfur is 28 ppm, the total amount of other metals is 2 ppm or less, 6-position acetyl group and propionyl group are 0.70 and 0.25 respectively, 6-position The total degree of conversion was 36% of the total substituents, the weight average molecular weight (Mw) was 220,000, and the number average molecular weight (Mn) was 69,000. The ratio (Mw / Mn) is 3.2, the yellowness index is 0.8, the haze is 0.2, the transparency is 93.0%, the Tg is 146 ° C., and the crystallization calorific value is 3.3 J / g. Met. The repose angle was 33 degrees, the bulk density was 0.35 g / cm ³ , the tap density was 0.40 g / cm ³ , and the compressibility was 25%. Further, 20 kg of a solution in which cellulose ester C was dissolved in a mixed solvent of methylene chloride / methanol (92/8 and 80/20 mass ratio) at room temperature (25 ° C.) was added to a filter paper having an average diameter of 10 μm and a thickness of 1 mm. Then, the filter paper was thoroughly washed with each solvent and the increased mass of the SUS filter was measured. The mass increase rate was 0.05% in the case of methylene chloride / methanol (92/8 mass ratio). In the case of methylene chloride / methanol (80/20 mass ratio), it was 0.09%.

  Cellulose ester D is cellulose acetate butyrate, acetyl substitution degree 1.69, butyrate substitution degree 1.25, total substitution degree 2.94, viscosity average polymerization degree 300, water content 0.1 mass%, methylene chloride solution 6 mass% viscosity 225 mPa · s, average particle diameter 1.0 mm, standard deviation 0.4 mm powder, residual acetic acid amount 100 ppm, butanoic acid amount 50 ppm, Ca 3 ppm, Mg 30 ppm, K Is 1 ppm, Na is 3 ppm, Fe is 0.9 ppm, sulfur (present as a sulfate group) is 28 ppm, 6-position acetyl group and propionyl group are 0.51 and 0.45, respectively, and the 6-position substituent is The sum is 33% of all substituents, the weight average molecular weight is 220,000, the number average molecular weight is 68,000, and the ratio (Mw / Mn) is 3.2, Yellow Ness index 0.9, haze 0.5, transparency 92.9%, Tg is 153 ° C., crystallization exotherm was 3.9 J / g.

  Cellulose ester E is cellulose acetate benzoate, acetyl substitution degree 1.89, benzoyl substitution degree 0.98, total substitution degree 2.87, viscosity average polymerization degree 290, water content 0.4 mass%, methylene chloride 6 wt% viscosity in solution of 320 mPa · s, powder having an average particle diameter of 1.5 mm and standard deviation of 0.4 mm, the amount of residual acetic acid and benzoic acid are both 0.03 wt% or less, Ca is 2 ppm, Mg Was 30 ppm, K was 4 ppm, Na was 9 ppm, Fe was 0.5 ppm, and sulfur (present as a sulfate group) was 21 ppm. The number average molecular weight (Mn) was 68,000, the weight average molecular weight (Mw) was 194,000, and Mw / Mn was 2.9. 6-position acetyl group and benzoic acid group are 0.82 and 0.06, respectively, 33% of all substituents, yellowness index 0.5, haze 0.6, transparency 93.4%, Tg 133 C., and the crystallization exotherm was 5.2 J / g.

[Example 3: Production and evaluation of transparent polymer film P301]
Except for further adding 3% by mass (based on polymer) of the following additive TA-1, the production of the polymer film P111 in Example 1 was exactly the same except that the plasticizer PA-13 was replaced with PA-6. A polymer film P301 of the present invention was produced. As described in Table 1, the film P301 was an optical film having excellent properties, satisfying all of roll dirt, ear cut-off state, and heat crying.

[Example 4: Production and evaluation of transparent polymer film P401]
Except that the film prepared in the film forming process according to the following film manufacturing method using the solution prepared in the above <(1) Preparation of polymer solution> was exactly the same as the polymer film P106 of the present invention in Example 1. Thus, a film P401 (the present invention) was obtained.

(Film P401 film forming process)
The polymer solution was heated to 30 ° C., and cast on a mirror surface stainless steel support, which was a drum having a diameter of 3 m, through a casting Giuser. The surface temperature of the support was set to −5 ° C., and the coating width was 1470 mm. The space temperature of the entire casting part was set to 15 ° C. Then, the cellulose ester film that had been cast and rotated 50 cm before the end point of the casting part was peeled off from the drum, and then both ends were clipped with a pin tenter. The residual solvent amount of the cellulose ester web immediately after stripping, the stripping speed (stripping roll draw) with respect to the support speed, and the film surface temperature of the cellulose ester web were 3 ° C.

  The cellulose ester web held by the pin tenter was conveyed to the drying zone. In the initial drying, a drying air of 45 ° C. was blown. Next, after drying at 110 ° C. for 10 minutes and further at 140 ° C. for 18 minutes, both ends (5% each of the total width) are cut off immediately before winding, and then both ends are 10 mm wide and 50 μm high (knurling) Was wound up into a 3000 m roll. The width of the transparent film thus obtained was 1.45 m at each level, and the film thickness was 40 μm. As described in Table 1, these films satisfy all the roll stains, the ear cut-off state, and the heat crying out, and have excellent characteristics with small Rth humidity dependency (ΔRth).

[Example 5: Production and evaluation of stretched polymer films P501 and 502]
The polymer film P301 produced in Example 3 was further stretched by the following method to obtain films 501 and 502. That is, both ends of the film P301 were gripped with a tenter clip and then stretched in a direction perpendicular to the transport direction in the heating zone (film P501). The temperature of the heating zone was 170 ° C., and the film was stretched 20% to obtain a film P501 of the present invention. In addition, the draw ratio put the mark line of a fixed space | interval in the direction parallel to the conveyance direction of a film, measured the space | interval before and behind extending | stretching, and calculated | required from the following formula.
Stretch ratio (%) = 100 × (interval between marked lines after stretching−interval between marked lines before stretching) / interval between marked lines before stretching The polymer film P501 obtained by re-stretching in this way is a film The thickness was 65 μm, Re was 58 nm, and Rth was 115 nm. This film satisfies all roll stains, ear-cut conditions, and heat crying, and has excellent characteristics with a small Rth humidity dependency (ΔRth) of 28 nm, and can be used as a useful retardation film. It can be done.
Film P501 except that the additive amount of additive TA-1 was changed to 6% by mass, the type of plasticizer was changed to the two types shown in Table 1, the temperature of the superheating zone was 175 ° C., and the film was stretched 28%. In the same manner as above, a stretched film P502 of the present invention was obtained. The obtained film P502 had a film thickness of 55 μm, Re of 65 nm, and Rth of 190 nm. This film satisfied all the roll stains, the ear cut-off state, and the heat crying out, and the humidity dependency (ΔRth) of Rth was as small as 26 nm, and it had excellent characteristics.

[Example 6: Production and evaluation of laminated retardation film]
The polymer film of the present invention can be used as a retardation film as it is, but here, a retardation film with a controlled Rth / Re ratio is prepared by laminating the film with a roll using a pressure-sensitive adhesive. did. Fujitac TD80UF (manufactured by Fuji Film Co., Ltd.) and the film P501 of the present invention produced in Example 5 were adhesive (made of poly (methyl acrylate / butyl acrylate / hydroxyethyl acrylate), toluene diisocyanate and diglycidyl ethylene glycol) Was used to produce a polarizing plate retardation film with Re = 63 nm and Rth = 158 nm. Further, the slow axis of Re of this retardation film was observed in the width direction of the film, and was an excellent planar shape as a polarizing plate.

[Example 7: Production and evaluation of polarizing plate]
(1) Saponification of film The polymer film P106 of the present invention was immersed in a 1.5 mol / L NaOH aqueous solution (saponification solution) maintained at 55 ° C for 2 minutes, and then the film was washed with water. After being immersed in a 0.05 mol / L sulfuric acid aqueous solution for 30 seconds, the film was neutralized by passing a washing bath under running water for 30 seconds. Then, draining with an air knife was repeated three times, and after dropping water, the film was retained in a drying zone at 70 ° C. for 15 seconds and dried to prepare a saponified film. The obtained film had an excellent surface shape, and the optical characteristics and the like almost maintained the characteristics before saponification.

(2) Production of Polarizing Film According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a circumferential speed difference was given between two pairs of nip rolls and stretched in the longitudinal direction to prepare a polarizing film having a thickness of 20 μm.
(3) Bonding The polarizing film obtained in this way and the saponified film (two sheets) were placed with the saponified surface of the film on the polarizing film side and sandwiched between the polarizing films, and then PVA (Puraray Co., Ltd., PVA-117H) Using a 3% aqueous solution as an adhesive, a polarizing plate 7001 was prepared by laminating so that the polarizing axis and the longitudinal direction of the film were orthogonal.
For the other samples, the evaluation results of the polarizing plate durability are shown in Table 1 in the same manner as when the polarizing plate of the polymer film P106 was prepared.

(4) Evaluation of polarizing plate (initial polarization degree)
The polarization degree of the polarizing plate was calculated by the following method. The initial polarization degree, temporal polarization degree 1 and temporal polarization degree 2 were all 99.99%, indicating excellent polarizing plate characteristics.
(Time polarization 1)
One film side of the polarizing plate was bonded to a glass plate with an adhesive, and allowed to stand for 500 hours at 60 ° C. and a relative humidity of 95%, and the degree of polarization after standing (degree of polarization over time) was calculated by the method described above. . The decrease in the degree of polarization after aging was 0.02% or less, which was an excellent durability characteristic.
(Time polarization 2)
One film side of the polarizing plate was bonded to a glass plate with an adhesive, and allowed to stand for 500 hours at 90 ° C. and a relative humidity of 0%, and the degree of polarization after standing (degree of polarization with time) was calculated by the method described above. However, the decrease in the degree of polarization was 0.02% or less, which was a level that would not cause a problem in practice.

[Example 8: Production and evaluation of transparent polymer films P801 and P802]
Polymer films P801 and P802 were produced in the same manner as in the production of the polymer film P106 of Example 1 of the present invention, except that the film thickness was 60 μm and 40 μm. As shown in Table 1, these films satisfy all of roll dirt, ear cut-off state, and heat crying, have excellent properties, and can be applied as useful retardation films.

[Example 9: Production and evaluation of polarizing plate]
A polarizing plate 901 and a polarizing plate 902 were produced in the same manner as in Example 7, except that the polymer film P106 in Example 7 was changed to P801 and P802 produced in Example 8. According to the evaluation method of Example 7 (4) polarizing plate, it was confirmed that the polarizing plate was excellent as in Example 7. That is, the initial polarization degree, the temporal polarization degree 1 and the temporal polarization degree 2 were all 99.99%, indicating excellent polarizing plate characteristics.

[Example 10: Production and evaluation of VA liquid crystal display device (single sheet type)]
According to Example 1 of JP 2007-272100 A, except that the polymer film P502 of the present invention produced in Example 5 is used in place of the film 1 described in Example 1 of JP 2007-272100 A. Then, a polarizing plate was produced and mounted on a VA panel (single-sheet type) to produce a VA liquid crystal display device. Even when the polymer film of the present invention was used, the viewing angle was excellent, and there was no color misregistration, panel warpage or peripheral light leakage. From the above, it was proved that the film of the present invention was excellent in application to a liquid crystal display device.

[Example 11: Production and evaluation of VA liquid crystal display device (two-sheet type)]
According to Example 3 of JP 2007-272100 A, except that the polymer film P501 of the present invention produced in Example 5 is used instead of the film 31 described in Example 3 of JP 2007-272100 A. Then, a polarizing plate was prepared and mounted on a VA panel (two-sheet type) to produce a VA liquid crystal display device. Even when the polymer film of the present invention was used, the viewing angle was excellent, and there was no color misregistration, panel warpage or peripheral light leakage. From the above, it was proved that the film of the present invention was excellent in application to a liquid crystal display device.

[Example 12: Production and evaluation of OCB liquid crystal display device]
Example of JP 2007-264259 A except that the polymer film P502 of the present invention produced in Example 5 is used in place of the cellulose acylate film described in Example 8 of JP 2007-264259 A According to 8, a polarizing plate was produced and mounted on an OCB panel with a viewing angle compensation film to produce an OCB liquid crystal display device. Even when the polymer film of the present invention was used, the viewing angle was excellent, and there was no color misregistration, panel warpage or peripheral light leakage. From the above, it was proved that the film of the present invention was excellent in application to a liquid crystal display device.

[Example 13: Production and evaluation of transparent polymer films P1316, 1321-1324]
P106 of Example 1 and P201 to P204 of Example 2 except that the solvent was changed to methylene chloride / methyl acetate / acetone / methanol / ethanol / butanol (45/40/5/5/3/2 mass ratio) The polymer films P1316 and 1321-1324 of the present invention were produced in exactly the same manner as the production. These films satisfy all roll stains, ear-cut conditions, and heat crying, have low haze, small dimensions, excellent polarizing plate durability and film durability, and excellent optical properties. It was.

[Example 14: Production and evaluation of transparent polymer films P1416, 1421-1424]
Except for changing the polymer film P111 to polymer films P1316 and 1321 to 1324, polymer films P1416 and 1421 to 1424 of the present invention containing the additive TA-1 were produced in exactly the same manner as in Example 3. These films satisfy all roll stains, ear-cut conditions, and heat crying, have low haze, small dimensions, excellent polarizing plate durability and film durability, and optical properties. It was excellent.

[Example 15: Production and evaluation of stretched polymer films P1516, 1521 to 1524]
Extruded polymer films P1516 and 1521 to 1524 of the present invention were produced in exactly the same manner as in Example 5 except that the polymer film P301 was changed to polymer films P1416 and 1421 to 1424. The obtained polymer films P1516 and 1521 to 1524 had a film thickness of approximately 55 μm, and Re / Rth were 68 nm / 125 nm, 75 nm / 130 nm, 60 nm / 115 nm, 45 nm / 105 nm, and 80 nm / 60 nm, respectively. In addition, these films satisfy all of roll dirt, ear cut-off state, heat crying out, have low haze, small size, excellent polarizing plate durability and film durability, and excellent A stretched film could be obtained.

[Example 16: Production and evaluation of liquid crystal display device]
JP, 2007-272100, A except that the polymer films P1516, 1521-1524 of the present invention produced in Example 15 are used in place of the film 1 described in Example 1 of JP, 2007-272100, A, respectively. According to Example 1, a polarizing plate was prepared and mounted on a VA panel (single-sheet type) to produce a VA liquid crystal display device. Even when the example film of the present invention was used, the viewing angle was excellent and there was no color misregistration, panel warpage or peripheral light leakage. From the above, it was proved that the film of the present invention was excellent in application to a liquid crystal display device.

[Example 17]
A polymer film P1701 of the present invention was produced in exactly the same manner as in the production of the polymer film P106 in Example 1, except that the cellulose ester A was changed to the following <cyclic polyolefin polymer P-1>. As described in Table 1, these films satisfy all of roll dirt, ear cut-off state, and heat crying, and are Rth humidity dependency (ΔRth) is small, and are optical films having excellent characteristics. It was.

<Synthesis of Cyclic Polyolefin Polymer P-1>
100 parts by mass of purified toluene and 100 parts by mass of norbornene carboxylic acid methyl ester were charged into a reaction kettle. Next, ethylhexanoate-Ni 25 mmol% (based on monomer mass) dissolved in toluene, tri (pentafluorophenyl) boron 0.225 mol% (based on monomer mass), and triethylaluminum 0.25 mol% (based on monomer mass) dissolved in toluene ) Was charged into the reaction kettle. The reaction was allowed to proceed for 18 hours at room temperature with stirring. After completion of the reaction, the reaction mixture was put into excess ethanol to produce a polymer precipitate. The cyclic polyolefin polymer (P-1) obtained by purifying the precipitate was dried at 65 ° C. for 24 hours by vacuum drying.

  The obtained polymer was dissolved in tetrahydrofuran and the molecular weight was measured by gel permeation chromatography. The number average molecular weight in terms of polystyrene was 79,000 and the weight average molecular weight was 205,000. The refractive index of the obtained polymer measured by Abbe's refractometer was 1.52.

[Example 18]
A polymer film P1801 was prepared and evaluated in the same manner as in the polymer film P106 except that the plasticizer PA-6 was changed to 12% by mass and the PB-10 was changed to 3% by mass (PA / PB ratio = 8/2). As shown in Table 3, P1801 was evaluated as “A” for all of the surface state, roll dirt, and ear-earing state.

[Example 19]
A polymer film P1901 was prepared and evaluated in the same manner as in the polymer film P106 except that the polymer plasticizer PA-23, which is a polymer plasticizer, was 7.5 mass% and PB-32 was 7.5 mass%. Further, a polymer film P1902 was prepared and evaluated in the same manner except that the plasticizer PA-23, which is a polymer plasticizer, was 7.5 mass% and PB-33 was 7.5 mass%. As shown in Table 3, all of P1901 and P1902 were evaluated as “A” in terms of the surface state, roll dirt, and ear-earing state, and other performances were also preferable as in the case of the polymer film P106 in Table 1. .

[Example 20]
A polymer film P2001 was prepared and evaluated in the same manner as in the polymer film P501 except that the polymer plasticizer was 7.5% by mass of the plasticizer PA-23 and 7.5% by mass of PB-32. The obtained stretched film had a film thickness of 60 μm, Re was 55 nm, and Rth was 112 nm. Like the polymer film P501, all of the surface state, roll dirt, and ear-earing state were “A” evaluations, which was a preferable performance. It was.

Claims (15)

A polymer film comprising a polymer and a high molecular weight plasticizer, the high molecular weight plasticizer comprising:
At least an aliphatic high molecular weight plasticizer (PA) which is a polycondensate obtained using an aliphatic dicarboxylic acid and an aliphatic diol as raw materials and has a number average molecular weight of 700 to 10,000,
A polycondensate obtained by using at least one of an aliphatic diol and a diol having at least one aromatic ring and a dicarboxylic acid having at least one aromatic ring as raw materials, and having a number average molecular weight of 700 to 10,000 An aromatic high molecular weight plasticizer (PB);
A total content of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 2 to 30% by mass with respect to the polymer, and the fat A polymer film having a mass ratio of the aromatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) of 1/9 to 9/1.   The aliphatic dicarboxylic acid used in the aliphatic high molecular weight plasticizer (PA) is at least one aliphatic dicarboxylic acid having 2 to 20 carbon atoms, and at least one used in the aromatic high molecular weight plasticizer (PB). The dicarboxylic acid having an aromatic ring is at least one kind of aromatic dicarboxylic acid having 8 to 20 carbon atoms, and is used for the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB). Group diol is an aliphatic diol having 2 to 20 carbon atoms or an alkyl ether diol having 4 to 20 carbon atoms, and the aromatic ring-containing diol used for the aromatic high molecular weight plasticizer (PB) is 6 to 20 carbon atoms. The polymer film according to claim 1, which is an aromatic ring-containing diol.   The aliphatic dicarboxylic acid used in the aliphatic high molecular weight plasticizer (PA) is malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, cyclohexanedicarboxylic acid, maleic acid or fumaric acid, Dicarboxylic acid having at least one aromatic ring used for aromatic high molecular weight plasticizer (PB) is phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1, The polymer film according to claim 1 or 2, which is 8-naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid.   The aliphatic diol used in the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2- Butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl) Glycol), 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, dicyclohexyldiol or dicyclohexyldimethanol, and at least one kind used for the aromatic high molecular weight plasticizer (PB). Diol having an aromatic ring is bisphenol A, 1,4-dihydroxybenzene Polymer film according to claim 1 other is benzene-1,4-dimethanol.   The aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) are obtained using an aliphatic monocarboxylic acid or an aliphatic monoalcohol further containing an aliphatic group having 1 to 22 carbon atoms. And an aromatic ring-containing monocyclic compound containing at least one selected from an aromatic ring-containing group having 6 to 20 carbon atoms, an aliphatic carbonyl group having 2 to 22 carbon atoms, and an aromatic carbonyl group having 7 to 20 carbon atoms. The polymer film according to any one of claims 1 to 4, which is obtained by using a carboxylic acid or an aromatic ring-containing monoalcohol.   The polymer film according to claim 5, wherein the aliphatic monocarboxylic acid is acetic acid, the aliphatic monoalcohol is ethylhexanol, and the aromatic ring-containing monocarboxylic acid is benzoic acid.   The mixing ratio (mass ratio) of the aliphatic high molecular weight plasticizer (PA) and the aromatic high molecular weight plasticizer (PB) is 2/8 to 8/2, and the aromatic high molecular weight plasticizer (PB) The polymer film according to any one of claims 1 to 6, wherein the dicarboxylic acid having an aromatic ring used is 25 to 100 mol% of the total dicarboxylic acid.   The polymer film according to any one of claims 1 to 7, wherein the content of a component having a number average molecular weight of 500 or less in the high molecular weight plasticizer is 10% by mass or less.   The polymer film according to any one of claims 1 to 8, wherein a mass reduction rate when the high molecular weight plasticizer is heated in air at 140 ° C for 60 minutes is 1% or less.   The polymer film according to any one of claims 1 to 9, which is a polyester film produced by a solution casting method or a melt casting method and having a thickness of 20 to 200 µm.   11. The polymer film according to claim 1, wherein the in-plane retardation (Re) is 0 to 300 nm and the retardation in the thickness direction (Rth) is −200 to +300 nm.   The polymer film is stretched 3% to 400% during or after film formation, the in-plane retardation (Re) is 30 to 200 nm, and the thickness direction retardation (Rth) is −50 to +250 nm. The polymer film according to claim 1.   A retardation film using the polymer film according to claim 1.   A polarizing plate having at least one of the polymer film according to claim 1 or the retardation film according to claim 13.   A liquid crystal display device comprising at least one of the polymer film according to claim 1, the retardation film according to claim 13, or the polarizing plate according to claim 14.