JP2006283013A - Acrylic resin film for optical use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an acrylic resin film for optical use which is excellent in quality, productivity, processability and heat resistance. <P>SOLUTION: The acrylic resin film has defects having a diameter of ≥5 μm in an amount of ≤1 pieces/10 cm square, and has a glass transition temperature being ≥110°C. The acrylic resin film is produced by a method for forming a film, which comprises blending 100 parts by weight of an acrylic resin having a glutaric acid anhydride unit with 5-50 parts by weight of acrylic elastomer particles having a difference in the refractive index between the elastomer and the acrylic resin of ≤0.05 and a particle size of ≥10 nm and ≤1,000 nm, followed by a solution film forming step. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical acrylic resin film excellent in quality, productivity, workability, and heat resistance.

  Acrylic resin films are excellent in transparency, surface gloss and light resistance, so liquid crystal display sheets or films, optical materials such as light guide plates, vehicle interior materials and exterior materials, vending machine exterior materials, electrification It is used for the surface skin of products, inner layers for building materials, exterior materials, etc., and is used in a wide range of fields such as protection of skins such as polycarbonate and vinyl chloride.

  In recent years, these resin films have been expanded to harsh usage environment conditions that require weather resistance and heat resistance, such as outdoors and in automobiles, due to the widespread use of, for example, automobile navigation systems and handy cameras. Yes. When used under such harsh environmental conditions, a sheet or film having a polymethyl methacrylate resin as a substrate has excellent transparency and weather resistance, but is deformed due to low heat resistance, and toughness Has a problem that it is easily broken during processing.

  Therefore, for the purpose of improving the heat resistance of the acrylic resin film, a film having a glutaric anhydride unit represented by the following structural formula (1) is disclosed. (Patent Document 1 and Patent Document 2)

  However, if the heat resistance is simply improved by adjusting the composition of the acrylic resin film, the flexibility is insufficient and the film is easily cracked by bending stress, and sufficient toughness required during processing cannot be obtained.

  In addition, for the purpose of simultaneously improving the heat resistance and toughness of the acrylic resin film, a crosslinked elastic body is contained in an acrylic resin containing a methyl methacrylate unit, a glutaric anhydride unit represented by the following structural formula (2), and a styrene unit. Disclosed film is disclosed (Patent Document 3).

  However, since this film contains styrene units in the acrylic resin, heat resistance and transparency are not sufficient, and flatness deteriorates when processed at high speed and high temperature and high tension to improve productivity, In applications where high light transmittance is required, such as for film, there is a problem that the performance is insufficient.

In addition, acrylic resin film can be formed by melt film formation or solution film formation, but when film is formed by melt film formation, the polymer is colored by raising the temperature with an extruder, or at the time of casting There have been problems such as unevenness in the thickness of die lines and the like, and filtration is difficult and defects due to foreign matters occur. The solution casting method has problems such as foaming accompanying solvent drying.
JP 7-268036 A (1 page) JP 2004-2711 A (page 1) JP 2000-178399 A (1 page)

  The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue. That is, an object of the present invention is to provide an optical acrylic resin film excellent in quality, productivity, workability, and heat resistance.

  The present invention for achieving the above object is achieved by an acrylic resin film having a defect of 5 μm or more in diameter of 1/10 cm square or less and a glass transition temperature of 110 ° C. or more.

  Since the acrylic resin film of the present invention is excellent in quality, workability, and heat resistance, it can be suitably applied to optical members such as image display elements.

The acrylic resin film of the present invention needs to have a glass transition temperature (Tg) of 110 ° C. or higher. More preferably, it is 120 degreeC or more, More preferably, it is 150 degreeC or more. If it is lower than 110 ° C., it may not be used in a high-temperature environment such as a projector or a vehicle-mounted display device. In addition, when a hard coat treatment or the like is performed on the film surface, the film may be deformed by heat and flatness may be impaired. The glass transition temperature referred to here is an intermediate value determined according to JIS K7121 (1987) using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer) at a temperature rising rate of 20 ° C./min. It is the point glass transition temperature (T _mg ).

  The acrylic resin film of the present invention has a defect of 5 μm or more in diameter in the film plane of 1 piece / 10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less. Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined. The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape, such as transfer of a roll flaw or an abrasion, the size is confirmed by observing the defect with the reflected light of a differential interference microscope. In addition, when observing with reflected light, if the size of the defect is unclear, aluminum or platinum is deposited on the surface for observation.

  In order to obtain a film having excellent quality expressed by such a defect frequency with high productivity, it is necessary to filter the polymer solution with high precision immediately before casting, to increase the cleanliness around the casting machine, It is effective to set drying conditions after rolling stepwise and to dry efficiently while suppressing foaming. If the number of defects is greater than 1/10 cm square, for example, when the film is tensioned during processing in a later step, the film may break with the defects as a starting point, and productivity may be significantly reduced. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise. Moreover, even when it cannot be visually confirmed, when a hard coat layer or the like is formed on the film, the coating agent may not be formed uniformly, resulting in a defect (missing coating). Here, the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign matter in the film forming stock solution, or a foreign matter mixed in the film forming. This refers to the foreign matter (foreign matter defect) in the film.

  The acrylic resin film of the present invention preferably has a breaking elongation in at least one direction of 10% or more, more preferably 20% or more in the measurement based on JIS-K7127-1999. If the elongation is low, breakage during molding and processing is not likely to occur. The upper limit of the elongation at break is not particularly limited, but is practically about 250%. In order to increase the elongation at break, it is effective to suppress defects in the film caused by foreign matter and foaming. Moreover, introduction of a bendable component into the polymer and addition of a plasticizer and the like are effective for increasing the elongation at break, but the heat resistance may be lowered.

  The thickness of the acrylic resin film of the present invention is preferably 30 μm or more. More preferably, it is 80 μm or more. When the thickness of the film is less than 30 μm, the film strength is lowered and processability is deteriorated. The upper limit of the thickness is not particularly limited, but in the case of forming a film by a solution casting method, the upper limit is about 250 μm from the viewpoint of applicability, foaming, solvent drying, and the like. In addition, what is necessary is just to select the thickness of a film suitably by a use.

  The acrylic resin film of the present invention preferably has a total light transmittance of 90% or more, more preferably 93% or more. Moreover, as a realistic upper limit, it is about 99%. In order to achieve excellent transparency expressed by such total light transmittance, it is necessary not to introduce additives and copolymerization components that absorb visible light, or to remove foreign substances in the polymer by high-precision filtration. It is effective to reduce the diffusion and absorption of light inside the film. Also, reduce the surface roughness of the film surface by reducing the surface roughness of the film contact part (cooling roll, calender roll, drum, belt, coating substrate in solution casting, transport roll, etc.) during film formation. It is also effective to reduce the diffusion and reflection of light on the film surface by reducing the refractive index of the acrylic resin (A).

  In addition, the acrylic resin film of the present invention preferably has a haze value (turbidity) that is one of the indices representing transparency of 2% or less, more preferably 1.5% or less, and most preferably 0. .5% or less. In order to achieve such a haze value, it is effective to reduce the difference in refractive index between the acrylic resin (A) and the acrylic elastic particles (B) as described above. Moreover, since the surface roughness also affects the haze value as surface haze, the particle diameter and addition amount of the acrylic elastic particles (B) are suppressed within the above range, or the surface roughness of the film contact portion during film formation is reduced. It is also effective to do. It is also effective to remove foreign substances in the polymer by high-precision filtration and reduce the diffusion of light inside the film.

  In addition, the total light transmittance and haze value of the said thermoplastic resin composition are the values measured according to JIS-K7361-1-1997 and JIS-K7136-2000.

  The acrylic resin film of the present invention can be preferably used as an optical acrylic resin film as long as it satisfies the physical properties described above. However, by having the following composition, the film has excellent workability and heat resistance. Can be obtained.

That is, from the viewpoint of achieving both workability and heat resistance, acrylic resin (A) 50 to 95 containing a glutaric anhydride unit represented by the following general formula (1) when the acrylic resin film is 100 parts by mass. It is preferable that it is an acrylic resin film which makes the main material the mixture which consists of 5 mass parts of mass parts and acrylic elastic-body particle | grains (B). Furthermore, it is preferable that it is an acrylic resin film which uses as a main material the mixture which consists of 75-95 mass parts of acrylic resins (A) and acrylic elastic-body particle | grains (B) from a transparent viewpoint.

(In the above formula, R ¹ and R ² represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.)
Next, although the example of the manufacturing method of the acrylic resin (A) containing the glutaric anhydride unit represented by the said General formula (1) is demonstrated, this invention is not limited to this.

  That is, the unsaturated carboxylic acid monomer (i) and the unsaturated carboxylic acid alkyl ester monomer (ii) that give the glutaric anhydride unit represented by the general formula (1) by the subsequent heating step, and the others When the vinyl monomer unit is included, the vinyl monomer (iii) providing the unit is polymerized to form a copolymer (a), and then the copolymer (a) is converted into a suitable catalyst. It can be produced by heating in the presence or absence of and causing an intramolecular cyclization reaction by dealcoholization and / or dehydration. In this case, the carboxyl group of the unsaturated carboxylic acid unit of 2 units is typically dehydrated by heating the copolymer (a), or the adjacent unsaturated carboxylic acid unit and unsaturated carboxylic acid alkyl ester unit. 1 unit of the glutaric anhydride unit is generated by the elimination of the alcohol. The unsaturated carboxylic acid monomer (i) used at this time is not particularly limited, and can be copolymerized with another vinyl compound (iii), and the unsaturated carboxylic acid monomer of the general formula (3) The body can be used.

(In the above formula, R ³ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.)
In particular, acrylic acid and methacrylic acid are preferable from the viewpoint of excellent thermal stability, and methacrylic acid is more preferable. These can be used alone or in combination of two or more thereof. The unsaturated carboxylic acid monomer (i) represented by the general formula (3) gives an unsaturated carboxylic acid unit having a structure represented by the general formula (1) when copolymerized.

  Further, the unsaturated carboxylic acid alkyl ester monomer (ii) is not particularly limited, but as a preferred example, those represented by the following general formula (4) can be raised.

(In the above formula, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. R ⁵ represents a hydrogen atom or an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms.)
Of these, acrylates and / or methacrylates having an aliphatic or alicyclic hydrocarbon group having 1 to 6 carbon atoms or a hydrocarbon group having a substituent are particularly preferred in terms of excellent thermal stability. is there. The unsaturated carboxylic acid alkyl ester monomer represented by the general formula (4) gives an unsaturated carboxylic acid alkyl ester unit having a structure represented by the general formula (1) when copolymerized.

  Preferable specific examples of the unsaturated carboxylic acid alkyl ester monomer (ii) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and n-butyl (meth) acrylate. T-butyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2- (meth) acrylic acid 2- Hydroxyethyl, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate and 2,3,4,5-tetrahydroxypentyl (meth) acrylate Among them, methyl methacrylate is most preferably used. These can be used alone or in combination of two or more thereof.

  Moreover, in manufacture of the acrylic resin (A) used by this invention, you may use another vinyl-type monomer (iii) in the range which does not impair the effect of this invention. Preferable specific examples of the other vinyl monomers (iii) include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, o-ethylstyrene, p-ethylstyrene and pt-butylstyrene. Aromatic vinyl monomers such as, vinyl cyanide monomers such as acrylonitrile, methacrylonitrile, ethacrylonitrile, allyl glycidyl ether, styrene-p-glycidyl ether, p-glycidyl styrene, maleic anhydride, anhydrous Itaconic acid, N-methylmaleimide, N-ethylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, aminoethyl acrylate, Propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, phenylaminoethyl methacrylate, cyclohexylaminoethyl methacrylate, N-vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallylamine , P-aminostyrene, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acryloyl-oxazoline, 2-styryl-oxazoline, etc., but transparency, birefringence, chemical resistance And a monomer that does not contain an aromatic ring is more preferably used. These may be used alone or in combination of two or more.

  As for the polymerization method of the acrylic resin (A), basically, polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization by radical polymerization can be used. Particularly preferred are bulk polymerization and suspension polymerization.

  The polymerization temperature is not particularly limited, but from the viewpoint of color tone, a monomer mixture containing an unsaturated carboxylic acid monomer and an unsaturated carboxylic acid alkyl ester monomer is polymerized at a polymerization temperature of 95 ° C. or less. Is preferred. Furthermore, in order to further suppress the coloration after the heat treatment, a preferable polymerization temperature is 85 ° C. or less, and particularly preferably 75 ° C. or less. The lower limit of the polymerization temperature is not particularly limited as long as the polymerization proceeds, but is usually 50 ° C. or higher, preferably 60 ° C. or higher from the viewpoint of productivity considering the polymerization rate. For the purpose of improving the polymerization yield or the polymerization rate, it is possible to raise the polymerization temperature according to the progress of the polymerization. In this case, the upper limit temperature is preferably controlled to 95 ° C. or less, and the polymerization start temperature Is preferably performed at a relatively low temperature of 75 ° C. or lower. The polymerization time is not particularly limited as long as it is a sufficient time to obtain the required degree of polymerization, but is preferably in the range of 60 to 360 minutes, particularly preferably in the range of 90 to 180 minutes from the viewpoint of production efficiency.

  In this invention, the preferable ratio of these monomer mixtures used at the time of manufacture of an acrylic resin (A) makes this monomer mixture 100 mass parts, and unsaturated carboxylic acid monomer (i) is 5-50. Parts by mass, more preferably 9-33 parts by mass, unsaturated carboxylic acid alkyl ester monomer (ii) is preferably 50-95 parts by mass, more preferably 67-91 parts by mass, other copolymerizable with these When using a vinyl-type monomer (iii), the preferable ratio is 0-5 mass parts, and a more preferable ratio is 0-3 mass parts.

  When the unsaturated carboxylic acid monomer amount (i) is less than 5 parts by mass, the amount of glutaric anhydride units represented by the above general formula (1) generated by heating the copolymer (a) is small. Thus, the heat resistance improvement effect of the acrylic resin film of the present invention tends to be small. On the other hand, when the unsaturated carboxylic acid monomer amount (i) exceeds 50 parts by mass, a large amount of unsaturated carboxylic acid units tend to remain after the cyclization reaction by heating the copolymer (a). , Colorless transparency and retention stability tend to decrease.

  Moreover, it is preferable that the acrylic resin (A) used for the acrylic resin film of the present invention has a mass average molecular weight of 80,000 to 150,000. In the acrylic resin (A) having such a molecular weight, the copolymer (a) is previously controlled to a desired molecular weight, that is, a mass average molecular weight of 50,000 to 150,000 at the time of producing the copolymer (a). Can be achieved. When the mass average molecular weight exceeds 150,000, there is a tendency to color at the time of heat deaeration in the subsequent step. On the other hand, when the mass average molecular weight is less than 50,000, the mechanical strength of the acrylic resin film tends to decrease.

  There is no restriction | limiting in particular about the molecular weight control method of a copolymer (a). For example, controlled by the amount of radical polymerization initiators such as azo compounds and peroxides, or the amount of chain transfer agents such as alkyl mercaptans, carbon tetrachloride, carbon tetrabromide, dimethylacetamide, dimethylformamide, triethylamine, etc. can do. In particular, a method of controlling the amount of alkyl mercaptan added as a chain transfer agent can be preferably used from the viewpoint of stability of polymerization, ease of handling, and the like.

  Examples of the alkyl mercaptan include n-octyl mercaptan, t-dodecyl mercaptan, n-dodecyl mercaptan, n-tetradecyl mercaptan, n-octadecyl mercaptan and the like, among which t-dodecyl mercaptan and n-dodecyl mercaptan are preferable. Used.

  The amount of the alkyl mercaptan added is not particularly limited as long as it is controlled to the specific molecular weight of the present invention, but is usually 0.2 to 5.5 with respect to 100 parts by mass of the total amount of the monomer mixture. 0 parts by mass, preferably 0.3 to 4.0 parts by mass, more preferably 0.4 to 3.0 parts by mass.

  The copolymer (a) used for the production of the acrylic resin (A) preferably used in the present invention is heated and subjected to intramolecular cyclization reaction by (i) dehydration and / or (b) dealcoholization to give glutaric anhydride units. There is no particular limitation on the method for producing a thermoplastic polymer containing benzene, but it can be produced by passing through a heated extruder having a vent or in an inert gas atmosphere or in an apparatus that can be devolatilized under vacuum. Is preferable from the viewpoint of productivity. Among them, when an intramolecular cyclization reaction is carried out by heating in the presence of oxygen, the yellowness tends to deteriorate, so it is preferable to sufficiently substitute the inside of the system with an inert gas such as nitrogen. As a particularly preferred apparatus, for example, a single screw extruder equipped with a “unimelt” type screw, a twin screw, a three screw extruder, a continuous or batch kneader type kneader, etc. can be used. The machine can be preferably used. Moreover, it is more preferable that the apparatus has a structure capable of introducing an inert gas such as nitrogen into them. For example, as a method for introducing an inert gas such as nitrogen into a twin-screw extruder, a method of connecting a pipe of an inert gas stream of about 10 to 100 liters / minute from the upper part and / or the lower part of the hopper can be mentioned. .

  The temperature for the devolatilization by the above method is not particularly limited as long as it is a temperature at which an intramolecular cyclization reaction occurs due to (i) dehydration and / or (b) dealcoholization, but is preferably in the range of 180 to 300 ° C. In particular, a range of 200 to 280 ° C. is preferable.

  In addition, the time for heating and devolatilization in this case is not particularly limited and can be appropriately set according to the desired copolymer composition, but is usually 1 minute to 60 minutes, preferably 2 minutes to 30 minutes, especially 3 to 3. A range of 20 minutes is preferred. In particular, the length / diameter ratio (L / D) of the extruder screw is preferably 40 or more in order to secure a heating time for allowing sufficient intramolecular cyclization reaction to proceed using an extruder. When an extruder with a short L / D is used, a large amount of unreacted unsaturated carboxylic acid units remain, so that the reaction proceeds again during the heat molding process, and there is a tendency for silver and bubbles to be seen in the molded product and molding retention. Sometimes the color tends to deteriorate significantly.

  Furthermore, in the present invention, when the copolymer (a) is heated by the above method or the like, one or more of acid, alkali and salt compounds may be added as a catalyst for promoting the cyclization reaction to glutaric anhydride. it can. There is no restriction | limiting in particular in the addition amount, About 0.01-1 mass part is suitable with respect to 100 mass parts of copolymers (a). There are no particular restrictions on the types of these acids, alkalis, and salt compounds, and examples of the acid catalyst include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, phosphorous acid, phenylphosphonic acid, and methyl phosphate. It is done. Examples of the basic catalyst include metal hydroxides, amines, imines, alkali metal derivatives, alkoxides, ammonium hydroxide salts and the like. Furthermore, examples of the salt-based catalyst include metal acetates, metal stearates, metal carbonates, and the like. However, it is necessary to add the catalyst in such a range that the color possessed by the catalyst does not adversely affect the coloring of the thermoplastic polymer and the transparency is not lowered. Among them, the compound containing an alkali metal can be preferably used because it exhibits an excellent reaction promoting effect with a relatively small addition amount. Specifically, hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, alkoxide compounds such as sodium methoxide, sodium ethoxide, sodium phenoxide, potassium methoxide, potassium ethoxide, and potassium phenoxide, lithium acetate And organic carboxylates such as sodium acetate, potassium acetate and sodium stearate, among which sodium hydroxide, sodium methoxide, lithium acetate and sodium acetate can be preferably used.

  The acrylic resin (A) preferably has a glass transition temperature (Tg) of 120 ° C. or higher in terms of heat resistance. The method for raising the glass transition temperature is not particularly limited, but the content of the glutaric anhydride unit represented by the general formula (1) in the acrylic resin (A) is increased, and / or the obtained film is Examples include orientation by stretching.

  As the acrylic resin (A) of the present invention, a copolymer comprising a glutaric anhydride unit represented by the general formula (1) and an unsaturated carboxylic acid alkyl ester unit can be preferably used. The content of the unsaturated carboxylic acid alkyl ester unit and the glutaric anhydride unit is not particularly limited as long as the mass average molecular weight and the glass transition temperature are within the scope of the present invention, but the glass transition temperature is within the scope of the present invention. Therefore, when the total of the unsaturated carboxylic acid alkyl ester unit and the glutaric anhydride unit is 100 parts by mass, preferably the unsaturated carboxylic acid alkyl ester unit is 50 to 90 parts by mass and the glutaric anhydride unit is 10 to 10 parts by mass. It consists of 50 parts by mass, and more preferably consists of 55 to 80 parts by mass of unsaturated carboxylic acid alkyl ester units and 20 to 45 parts by mass of glutaric anhydride units. When the glutaric anhydride unit is less than 10 parts by mass, not only the effect of improving heat resistance is reduced, but also sufficient birefringence characteristics (optical isotropy) and chemical resistance tend not to be obtained.

In addition, an infrared spectrophotometer or a proton nuclear magnetic resonance (1H-NMR) measuring instrument is generally used for quantification of each component unit in the acrylic resin (A) of the present invention. In infrared spectroscopy, glutaric anhydride units, absorption of 1800 cm ^-1 and 1760 cm ^-1 are characteristic can be distinguished from unsaturated carboxylic acid units and unsaturated carboxylic acid alkyl ester unit. In the 1H-NMR method, for example, in the case of a copolymer consisting of a glutaric anhydride unit, methacrylic acid, and methyl methacrylate, the attribution of the spectrum in dimethyl sulfoxide heavy solvent is 0.5 to 1.5 ppm. The peak is methacrylic acid, methyl methacrylate and α-methyl group hydrogen of glutaric anhydride ring compound, the peak of 1.6 to 2.1 ppm is hydrogen of the methylene group of the polymer main chain, and the peak of 3.5 ppm is methacrylic acid The hydrogen of methyl carboxylic acid ester (—COOCH 3), the peak at 12.4 ppm can determine the copolymer composition from the hydrogen of carboxylic acid of methacrylic acid and the integral ratio of the spectrum. In addition to the above, in the case of a copolymer containing styrene as another copolymer component, hydrogen of an aromatic ring of styrene is seen at 6.5 to 7.5 ppm, and the copolymer is similarly obtained from the spectral ratio. The composition can be determined.

  The acrylic resin (A) of the present invention can contain other unsaturated carboxylic acid units and / or other copolymerizable vinyl monomer units in the acrylic resin (A).

  The amount of other unsaturated carboxylic acid units contained in 100 parts by mass of the thermoplastic polymer of the present invention is preferably 10 parts by mass or less, that is, 0 to 10 parts by mass, more preferably 0 to 5 parts by mass, Most preferably, it is 0-1 mass part. When the unsaturated carboxylic acid unit exceeds 10 parts by mass, the colorless transparency and the residence stability tend to decrease.

  Further, the amount of other copolymerizable vinyl monomer units is preferably 5 parts by mass or less, that is, in the range of 0 to 5 parts by mass, more preferably 0 to 3 parts in 100 parts by mass of the thermoplastic polymer. Part by mass. In particular, when an aromatic vinyl monomer unit such as styrene is contained and the content exceeds the above range, colorless transparency, optical isotropy, and chemical resistance tend to decrease.

  In the present invention, by dispersing the acrylic elastic particles (B) in the acrylic resin (A), the elongation and toughness are improved without greatly detracting from the excellent characteristics of the acrylic resin (A), and excellent processing is achieved. Sex can be imparted. As the acrylic elastic particles (B), a multilayer polymer called a so-called core-shell type composed of a layer containing one or more rubber-like polymers and one or more layers composed of different types of polymers. Acrylic elastic particles (b-1) or a graft copolymer obtained by copolymerizing a monomer mixture composed of a vinyl monomer in the presence of a rubber-like polymer. -2) and the like can be preferably used, and more preferably acrylic elastic particles (b-1) which are multi-layered polymers.

  The acrylic elastic particles (b-1), which is a core-shell multilayer polymer used in the present invention, is not particularly limited in the number of layers constituting the core elastic particles (b-1). It may be three or more layers or four or more layers, but it must be a multilayer structure polymer having a rubber elastic body layer composed of at least one rubber polymer inside.

  In the acrylic elastic particle (b-1) which is the multilayer structure polymer of the present invention, the type of the rubber elastic layer is not particularly limited, and may be composed of a polymer component having rubber elasticity. That's fine. For example, a rubber composed of a polymer obtained by polymerizing an acrylic component, a silicone component, a styrene component, a nitrile component, a conjugated diene component, a urethane component or an ethylene component, a propylene component, an isobutene component, and the like can be given. Preferred rubber elastic bodies include, for example, acrylic components such as ethyl acrylate units and butyl acrylate units, silicone components such as dimethylsiloxane units and phenylmethylsiloxane units, styrene components such as styrene units and α-methylstyrene units, and acrylonitrile. It is a rubber elastic body composed of nitrile components such as units and methacrylonitrile units and conjugated diene components such as butanediene units and isoprene units. A rubber elastic body composed of a combination of two or more of these components is also preferable. For example, (1) acrylic components such as ethyl acrylate units and butyl acrylate units, dimethylsiloxane units and phenylmethylsiloxane units (2) rubber elastic bodies composed of acrylic components such as ethyl acrylate units and butyl acrylate units and styrene components such as styrene units and α-methylstyrene units, (3) ) Rubber elastic bodies composed of acrylic components such as ethyl acrylate units and butyl acrylate units and conjugated diene components such as butanediene units and isoprene units, and (4) acrylic components such as ethyl acrylate units and butyl acrylate units. , Dimethylsiloxane units and phenyl Such as styrene component configured rubber elastic body such as silicone component and styrene units and α- methyl styrene unit, such as a chill siloxane units and the like. In addition to these components, a rubber elastic body obtained by crosslinking a copolymer composed of a crosslinking component such as a divinylbenzene unit, an allyl acrylate unit and a butylene glycol diacrylate unit is also preferable.

  In the acrylic elastic particle (b-1) which is the multilayer structure polymer of the present invention, the type of the layer other than the rubber elastic layer is particularly limited as long as it is composed of a polymer component having thermoplasticity. Although it is not a thing, it is preferable that it is a polymer component whose glass transition temperature is higher than a rubber elastic-body layer. Polymers having thermoplastic properties include unsaturated carboxylic acid alkyl ester units, unsaturated carboxylic acid units, unsaturated glycidyl group-containing units, unsaturated dicarboxylic acid anhydride units, aliphatic vinyl units, and aromatic vinyls. Examples include polymers containing at least one unit selected from system units, vinyl cyanide units, maleimide units, unsaturated dicarboxylic acid units and other vinyl units. Among them, unsaturated carboxylic acids A polymer containing at least one unit selected from an alkyl ester unit, an unsaturated glycidyl group-containing unit, and an unsaturated dicarboxylic acid anhydride unit is preferable, and further, an unsaturated glycidyl group-containing unit and an unsaturated dicarboxylic acid A polymer containing at least one unit selected from anhydride-based units is more preferable.

  Although it does not specifically limit as a monomer used as the raw material of the said unsaturated carboxylic-acid alkylester type | system | group unit, (meth) acrylic-acid alkylester is used preferably. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, (meth) acrylic N-hexyl acid, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl (meth) acrylate, octadecyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, ( Chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6 (meth) acrylic acid -Pentahydroxyhexyl, 2,3,4,5-tetrahydroxypentyl (meth) acrylate, amino acid acrylate Examples include ethyl, propylaminoethyl acrylate, dimethylaminoethyl methacrylate, ethylaminopropyl methacrylate, phenylaminoethyl methacrylate, and cyclohexylaminoethyl methacrylate, and from the viewpoint that the effect of improving impact resistance is large ( Methyl methacrylate is preferably used. These units can be used alone or in combination of two or more.

  The unsaturated carboxylic acid monomer is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, maleic acid, and further a hydrolyzate of maleic anhydride. Acrylic acid is particularly excellent in terms of thermal stability. Methacrylic acid is preferable, and methacrylic acid is more preferable. These can be used alone or in combination.

  The monomer used as the raw material for the unsaturated glycidyl group-containing unit is not particularly limited, and is glycidyl (meth) acrylate, glycidyl itaconate, diglycidyl itaconate, allyl glycidyl ether, styrene-4-glycidyl ether. And 4-glycidylstyrene, and glycidyl (meth) acrylate is preferably used from the viewpoint that the effect of improving impact resistance is great. These units can be used alone or in combination of two or more.

  Examples of the monomer used as a raw material for the unsaturated dicarboxylic acid anhydride unit include maleic anhydride, itaconic anhydride, glutaconic anhydride, citraconic anhydride, and aconitic anhydride, and the effect of improving impact resistance. From the standpoint of large, maleic anhydride is preferably used. These units can be used alone or in combination of two or more.

  Examples of the monomer that is a raw material for the aliphatic vinyl-based unit include ethylene, propylene, and butadiene. Examples of the monomer that is a raw material for the aromatic vinyl-based unit are styrene, α-methylstyrene, 1 -Vinyl naphthalene, 4-methyl styrene, 4-propyl styrene, 4-cyclohexyl styrene, 4-dodecyl styrene, 2-ethyl-4-benzyl styrene, 4- (phenylbutyl) styrene, halogenated styrene, etc. Acrylonitrile, methacrylonitrile, ethacrylonitrile, etc. are used as the raw material for the vinyl-based unit, and maleimide, N-methylmaleimide, N-ethylmaleimide are used as the monomer for the maleimide-based unit. N-propylmaleimide, N-isopropylmaleimide, Examples of monomers that can be used as raw materials for the unsaturated dicarboxylic acid units include maleic acid and maleic acid such as -cyclohexylmaleimide, N-phenylmaleimide, N- (p-bromophenyl) maleimide, and N- (chlorophenyl) maleimide. Monoethyl ester, itaconic acid, phthalic acid, and the like, which are monomers used as raw materials for the other vinyl units, include acrylamide, methacrylamide, N-methylacrylamide, butoxymethylacrylamide, N-propylmethacrylamide, N- Vinyldiethylamine, N-acetylvinylamine, allylamine, methallylamine, N-methylallylamine, p-aminostyrene, 2-isopropenyl-oxazoline, 2-vinyl-oxazoline, 2-acryloyl-oxazoline, and 2-styrene Examples include ril-oxazoline, and these monomers can be used alone or in combination of two or more.

  In the acrylic elastic particles (b-1) which is a multilayer structure polymer containing the rubber polymer of the present invention, the type of the outermost layer is not particularly limited, and is an unsaturated carboxylic acid alkyl ester unit, Unsaturated carboxylic acid unit, unsaturated glycidyl group-containing unit, aliphatic vinyl unit, aromatic vinyl unit, vinyl cyanide unit, maleimide unit, unsaturated dicarboxylic acid unit, unsaturated dicarboxylic anhydride unit And at least one selected from polymers containing units and other vinyl units, among others, unsaturated carboxylic acid alkyl ester units, unsaturated carboxylic acid units, unsaturated glycidyl group-containing units, and At least one selected from polymers containing unsaturated dicarboxylic acid anhydride units is preferred, and further, unsaturated carboxylic acid alkyls are preferred. Ester units, polymers containing unsaturated carboxylic acid-based units are more preferable.

  Furthermore, when the outermost layer in the acrylic elastic particle (b-1) which is the multilayer structure polymer is a polymer containing an unsaturated carboxylic acid alkyl ester unit and an unsaturated carboxylic acid unit, heating is performed. Thus, it was found that the intramolecular cyclization reaction proceeds in the same manner as in the production of the acrylic resin (A) of the present invention described above to produce the glutaric anhydride unit represented by the general formula (1). . Accordingly, the acrylic elastic particles (b-1), which is a multilayer structure polymer having a polymer containing an unsaturated carboxylic acid alkyl ester unit and an unsaturated carboxylic acid unit in the outermost layer, is blended in the acrylic resin (A). In the acrylic resin (A) that becomes a continuous phase (matrix phase) by heating, melting and kneading under appropriate conditions, the outermost layer contains the glutaric anhydride unit represented by the above general formula (1). By dispersing the acrylic elastic particles (b-1), which is a multilayer structure polymer having a polymer formed as described above, a good dispersion state is possible without agglomeration, and improvement in mechanical properties such as impact resistance is achieved. It is considered that extremely high transparency can be expressed.

  The monomer used as the raw material for the unsaturated carboxylic acid alkyl ester unit herein is not particularly limited, but (meth) acrylic acid alkyl ester is preferred, and methyl (meth) acrylate is more preferred. Preferably used.

  Further, the monomer used as a raw material for the unsaturated carboxylic acid unit is not particularly limited, but (meth) acrylic acid is preferable, and methacrylic acid is more preferably used.

  As a preferable example of the acrylic elastic particles (b-1) which is the multilayer structure polymer of the present invention, the core layer is butyl acrylate / styrene polymer, and the outermost layer is methyl methacrylate / the above general formula (1). A copolymer composed of glutaric anhydride units represented, or methyl methacrylate / glutaric anhydride units represented by the above general formula (1) / methacrylic acid polymer, and the core layer is dimethylsiloxane / acrylic Butyl acid polymer with outermost layer of methyl methacrylate polymer, core layer with butanediene / styrene polymer and outermost layer with methyl methacrylate polymer, and core layer with butyl acrylate polymer and outermost layer In which is a methyl methacrylate polymer ("/" indicates copolymerization). Further, a preferable example is one in which either one or both of the rubber elastic body layer and the outermost layer is a polymer containing a glycidyl methacrylate unit. Among them, the core layer is butyl acrylate / styrene polymer, and the outermost layer is methyl methacrylate / a copolymer of glutaric anhydride units represented by the above general formula (1), or methyl methacrylate / the above general formula. In the resin composition, the glutaric anhydride unit represented by (1) / methacrylic acid polymer approximates the refractive index with the acrylic resin (A) that is the continuous phase (matrix phase), and It is possible to obtain a good dispersion state, and the transparency that can satisfy the demand for more advanced in recent years is expressed.

  The particle diameter of the acrylic elastic particles (b-1), which is a multilayer structure polymer preferably used in the present invention, is not particularly limited, but is preferably 10 nm or more and 1000 μm or less, and more preferably 20 nm. As described above, the thickness is more preferably 100 μm or less, and most preferably 50 nm or more and 400 nm or less.

  In the acrylic elastic particle (b-1) which is a multilayer structure polymer preferably used in the present invention, the mass ratio of the core and the shell is not particularly limited, but the entire multilayer structure polymer is 100 parts by mass. The core layer is preferably 50 parts by mass or more and 90 parts by mass or less, more preferably 60 parts by mass or more and 80 parts by mass or less.

  As the multilayer structure polymer preferably used in the present invention, a commercially available product that satisfies the above-described conditions may be used.

  Examples of such commercially available products having a multilayer structure include, for example, “Metablene” manufactured by Mitsubishi Rayon Co., Ltd., “Kane Ace” manufactured by Kaneka Chemical Co., Ltd., “Paraloid” manufactured by Kureha Chemical Co., Ltd. Acryloid "," Staffroid "manufactured by Ganz Kasei Kogyo Co., Ltd., and" Parapet SA "manufactured by Kuraray Co., Ltd. can be used. These can be used alone or in combination of two or more.

  Moreover, as a specific example of the acrylic elastic particle (b-2) which is a graft copolymer suitably used as the acrylic elastic particle (B) preferably used in the present invention, in the presence of a rubbery polymer, A monomer comprising an unsaturated carboxylic acid ester monomer, an unsaturated carboxylic acid monomer, an aromatic vinyl monomer, and, if necessary, other vinyl monomers copolymerizable therewith And a graft copolymer obtained by copolymerizing a body mixture.

  The rubbery polymer used for the acrylic elastic particles (b-2) that are the graft copolymer is not particularly limited, but diene rubber, acrylic rubber, ethylene rubber, and the like can be used. Specific examples include polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, polyisoprene, butadiene-methyl methacrylate copolymer. , Butyl acrylate-methyl methacrylate copolymer, butadiene-ethyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-isoprene copolymer, and ethylene-acrylic acid Examples thereof include a methyl copolymer. These rubbery polymers can be used alone or in a mixture of two or more.

  Although there is no restriction | limiting in particular in the mass mean particle diameter of the rubber-like polymer which comprises the acrylic elastic-body particle | grains (b-2) which is a graft copolymer in this invention, 0.01-0.5 micrometer, Especially 0.05 A range of ˜0.4 μm is preferable. If it is less than the above range, the impact strength of the resulting thermoplastic composition tends to decrease, and if it exceeds the above range, transparency may decrease. The mass average particle size of the rubbery polymer depends on the sodium alginate method described in `` Rubber Age, Vol. 88, p.484-490 (1960), by E. Schmidt, PHBiddison '', that is, the concentration of sodium alginate. It can measure by the method of calculating | requiring the particle diameter of 50% of cumulative mass fraction from the mass ratio of creamed and the cumulative mass fraction of sodium alginate density | concentration using the polybutadiene particle diameter to cream.

  The acrylic elastic particles (b-2) which is a graft copolymer in the present invention has a rubber polymer of 10 to 80 parts by weight, preferably 20 to 70 parts by weight, when the particles are taken as 100 parts by weight. Preferably, it is obtained by copolymerizing 20 to 90 parts by weight, preferably 30 to 80 parts by weight, more preferably 40 to 70 parts by weight of the monomer (mixture) in the presence of 30 to 60 parts by weight. . When the ratio of the rubbery polymer is less than the above range or exceeds the above range, the impact strength and the surface appearance may be lowered.

  The acrylic elastomer particles (b-2), which is a graft copolymer, may contain an ungrafted copolymer that is produced when the monomer mixture is graft copolymerized with the rubber polymer. . However, from the viewpoint of impact strength, the graft ratio is preferably 10 to 100%. Here, the graft ratio is a mass ratio of the grafted monomer mixture to the rubbery polymer. In addition, the intrinsic viscosity measured at 30 ° C. of the methylethylketone solvent of the ungrafted copolymer is not particularly limited, but 0.1 to 0.6 dl / g is a balance between impact strength and moldability. From the viewpoint of, it is preferably used.

  The intrinsic viscosity of the acrylic elastomer particles (b-2), which is a graft copolymer in the present invention, measured at 30 ° C. is not particularly limited, but is 0.2 to 1.0 dl / g. From the viewpoint of the balance between impact strength and moldability, it is preferably used, more preferably 0.3 to 0.7 dl / g.

  There is no restriction | limiting in particular in the manufacturing method of acrylic elastic-body particle | grains (b-2) which is a graft copolymer in this invention, It can obtain by polymerization methods, such as block polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. .

  Moreover, since the transparency of the acrylic resin film of this invention can be obtained when each refractive index of an acrylic resin (A) and an acrylic elastic body particle (B) is approximated, it is preferable. Specifically, the refractive index difference between the acrylic elastic particles (B) and the acrylic resin (A) is preferably 0.05 or less, more preferably 0.02 or less, especially 0.01 or less. preferable. In order to satisfy such a refractive index condition, a method of adjusting each monomer unit composition ratio of the acrylic resin (A) and / or a rubbery polymer or single polymer used for the acrylic elastic particles (B). The refractive index difference can be reduced by a method of adjusting the composition ratio of the monomer, and an acrylic resin film excellent in transparency can be obtained.

  The difference in refractive index referred to here is a solution in which the acrylic resin film of the present invention is sufficiently dissolved in a solvent in which the acrylic resin (A) is soluble to obtain a cloudy solution, which is subjected to an operation such as centrifugation. The solvent is separated into a soluble part and an insoluble part, and the soluble part (acrylic resin (A)) and the insoluble part (acrylic elastic particle (B)) are purified, respectively, and then the measured refractive index (23 ° C., measured) Wavelength: 550 nm).

  In addition, the copolymer composition of the acrylic resin (A) and the acrylic elastic particles (B) in the substantial acrylic resin film is obtained by separating each of the components individually by separating the soluble component and the insoluble component using the solvent. It can be analyzed.

  In addition, the acrylic resin film of the present invention has other thermoplastic resins (for example, polyethylene, polypropylene, acrylic resin, polyamide, polyphenylene sulfide resin, polyether ether ketone resin, polyester, polysulfone, Polyphenylene oxide, polyacetal, polyimide, polyetherimide, etc.), thermosetting resins (for example, phenol resin, melamine resin, polyester resin, silicone resin, epoxy resin, etc.) can be further added, and hindered Phenolic, benzotriazole, benzophenone, benzoate, and cyanoacrylate UV absorbers and antioxidants, higher fatty acids, acid esters, and acid amides, and higher alcohols Lubricants and plasticizers, montanic acid and salts thereof, esters thereof, half esters thereof, release agents such as stearyl alcohol, stearamide and ethylene wax, anti-coloring agents such as phosphites and hypophosphites, Add optional additives such as halogen-based flame retardants, phosphorus-based or silicone-based non-halogen-based flame retardants, nucleating agents, amine-based, sulfonic acid-based, polyether-based antistatic agents, pigments and other colorants. May be. However, in light of the characteristics required by the application to be applied, it is necessary to add the additive within a range in which the color of the additive does not adversely affect the thermoplastic polymer and the transparency is not lowered.

  In the present invention, the method of blending the acrylic resin (A) with optional components such as acrylic elastic particles (B) or other additives is not particularly limited, and the acrylic resin (A) and other optional components are blended in advance. Thereafter, a method of uniformly melt-kneading with a single-screw or twin-screw extruder at 200 to 350 ° C. is preferably used. Moreover, when mix | blending acrylic elastic body particle | grains (B), the method of removing a solvent can be used after mixing in the solution of the solvent which melt | dissolves both (A) and (B) component.

  Next, although the example of the film forming method of the obtained acrylic resin is demonstrated, this invention is not limited to this.

  Production methods such as inflation method, T-die method, calendar method, cutting method, casting method, emulsion method, hot press method, etc. can be used as the method for producing the acrylic resin film of the present invention. From the viewpoint of suppression of defects and suppression of optical defects such as die lines, solution casting by casting is preferred.

  The solution casting method includes a dry-wet method, a dry method, a wet method, etc., and any method may be used, but here, the dry method will be described as an example.

  As a film-forming stock solution, when a polymer is polymerized by solution polymerization or the like, the polymer solution may be used as it is, or a polymer once isolated in a solvent may be used.

  As the solvent, solvents such as tetrahydrofuran, acetone, methyl ethyl ketone, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone and the like can be used, and preferably acetone, methyl ethyl ketone, N-methylpyrrolidone and the like can be used. As the solvent, one kind of solvent may be used, or two or more kinds of solvents may be mixed and used. Moreover, you may add a drying adjuvant, a release agent, etc. for the purpose of the drying acceleration of a solvent, or the peelability improvement from a base material. The polymer concentration in the film-forming stock solution is preferably about 2 to 50% by mass. If the concentration is low, the surface properties of the film deteriorate, and it takes a long time to dry the solvent. When the concentration is high, the fluidity of the polymer solution is lowered or the solubility is deteriorated. The polymer concentration is more preferably 10 to 45% by mass, still more preferably 15 to 40% by mass.

  The polymer solution after the concentration adjustment is preferably filtered to remove foreign matters and gel-like substances. By removing the foreign matter, the defects are reduced and the film can be usefully used as an optical application film. It is preferable that the filtration accuracy can remove foreign matters of 50 μm or more. More preferably, it is 10 μm, and most preferably 1 μm. It is preferable to perform filtration step by step with a plurality of filters having different filtration accuracy because the filtration life is extended. Filtration can be carried out at a temperature of 25 ° C. or higher and 100 ° C. or lower as appropriate with a filter such as a sintered metal, porous ceramic, sand, or wire mesh.

  When forming a film by a dry method, the stock solution is extruded from a die onto a support such as a drum, endless belt, or process film to form a film, and in the subsequent drying process, the solvent is scattered from the film layer to self-retain the film. To obtain a film which can be peeled off from the support.

  The temperature condition of the drying process can be performed in the range of room temperature to 220 ° C., for example. In order to remove the solvent efficiently, it is preferable to raise the drying temperature stepwise. The initial drying temperature is preferably in the range of (bp-40 ° C.) to bp, where bp is the boiling point of the solvent used. More preferably, it is (bp-40 degreeC)-(bp-20 degreeC). If the initial drying temperature is too low, the solvent drying takes time and the productivity deteriorates. If the initial drying temperature is higher than the boiling point of the solvent, foaming defects may occur. The solvent concentration in the film after the initial drying is preferably 10 to 30% by mass, and the time required for the initial drying is usually about 30 seconds to 5 minutes. Next, the film after initial drying is preferably subjected to secondary drying in the temperature range of (Tg-50 ° C.) to Tg, where Tg is the glass transition temperature of the polymer. If the secondary drying temperature is too low, it takes time to dry the solvent and the productivity deteriorates. If the temperature is Tg or higher, foaming defects may occur when the residual solvent in the film volatilizes. The solvent concentration in the film after secondary drying is preferably 2 to 15% by mass, and the time required for secondary drying is usually about 5 to 60 minutes. The film after the secondary drying is preferably final dried at a temperature equal to or lower than the polymer decomposition temperature to reduce the solvent concentration in the film to less than 2% by mass. When the solvent concentration is 2% by mass or more, the solvent may be eluted when used as a product.

  For example, when the obtained film is formed using the process film as a base material, the film may be wound while being laminated, or may be peeled off from the base material during or at the end of the drying process. In the case of peeling from the substrate, it is preferable to stack a protective film and wind it up, since scratches are suppressed. Further, if the surface of the drum, endless belt, process film, etc. used in the drying process is as smooth as possible, a film having a smooth surface can be obtained.

  The obtained film may be subjected to a treatment such as stretching and lamination of a hard coat layer or an antireflection layer in a subsequent step.

  The acrylic resin film of the present invention utilizes its excellent transparency, heat resistance, light resistance, and toughness to make housings for electrical / electronic parts, optical members, automobile parts, mechanical mechanism parts, OA equipment, home appliances, etc. It can be used for various applications such as parts and general miscellaneous goods.

  Specific applications of the molded product include, for example, various covers, various terminal boards, printed wiring boards, speakers, microscopes, binoculars, cameras, optical instruments represented by watches, and excellent transparency and heat resistance. From the point of view, finder such as camera, VTR, projection TV, filter, prism, Fresnel lens, etc. as video equipment related parts, various optical disc (VD, CD, DVD, MD, LD, etc.) substrates as optical recording / optical communication related parts Information equipment related parts such as protective films, optical switches, optical connectors, etc., liquid crystal displays, flat panel displays, plasma display light guide plates, Fresnel lenses, polarizing plates, polarizing plate protective films, retardation films, light diffusion films, viewing angles Magnifying film, reflective film, antireflection film, antiglare film Brightness enhancement film, conductive films for touch panels, covers, etc., is very useful for these various applications.

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto.
In addition, the measuring method of a physical property and the evaluation method of an effect were performed in accordance with the following method.

1. Glass transition temperature (Tg)
Using a differential scanning calorimeter (DSC-7 manufactured by Perkin Elmer), the measurement was performed at a temperature increase rate of 20 ° C./min in a nitrogen atmosphere. The sample amount was 5 mg.

The glass transition temperature here was measured at a rate of temperature increase of 20 ° C./min using a differential scanning calorimeter (DSC-7 manufactured by Perkin Elmer) and determined according to JIS K7121 (1987). The midpoint glass transition temperature (T _mg ).

2. Transparency (total light transmittance, haze value)
Using a direct reading haze meter manufactured by Toyo Seiki Co., Ltd., the total light transmittance (%) and haze value (haze) (%) at 23 ° C. were measured three times, and the transparency was evaluated with an average value. A halogen lamp (12V50W) was used as the light source, the total light transmittance was measured according to JIS-K7361-1997, and the haze was measured according to JIS-K7136-2000.

3. Elongation at break The average value was obtained by measuring five times in an atmosphere of 25 ° C. and 65% RH using an Instron type tensile tester according to the method defined in JIS K7127-1999.

4). Film thickness Five points were measured using a micro thickness gauge (manufactured by Anritsu), and an average value was obtained.

5. Refractive Index, Refractive Index Difference Acetone is added to the acrylic resin film of the present invention and refluxed for 4 hours, and this solution is centrifuged at 9,000 rpm for 30 minutes to obtain acetone soluble components (component (A)) and insoluble components (( B) component). These were dried under reduced pressure at 60 ° C. for 5 hours. Each of the obtained solids was press-molded at 250 ° C. to form a film having a thickness of 0.1 mm, and then the refractive index at 23 ° C. and 550 nm wavelength was measured with an Abbe refractometer (manufactured by Atago Co., Ltd., DR-M2). It was measured. In addition, the absolute value was used about the refractive index difference of (A) component and (B) component.

6). Defect frequency / size Defects in a 1 m ² film plane were detected using a transmission-type defect detector. The detected defect was observed with a microscope to determine the diameter of the defect. Here, the diameter of the defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope by the following method, and the maximum diameter (diameter of circumscribed circle) is determined. The range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object. When the defect is a change in the surface shape, such as transfer of a roll flaw or an abrasion, the size is confirmed by observing the defect with the reflected light of a differential interference microscope. When observing with reflected light, if the size of the defect is unclear, aluminum or platinum may be deposited on the surface for observation.

Of the defects whose diameters have been determined as described above, the number of defects having a diameter of 5 μm or more is determined. The number of defects having a diameter of 5 μm or more per 1 m ² was divided by 100 to determine the number of defects having a diameter of 5 μm or more per 10 cm square, that is, the frequency of defects (pieces / 10 cm square).

7). Mass average molecular weight (absolute molecular weight)
Gel permeation chromatograph (pump: model 515, manufactured by Waters, column: TSK-gel-GMHXL, Tosoh Corporation) equipped with a DAWN-DSP type multi-angle light scattering photometer (manufactured by Wyatt Technology) using dimethylformamide as a solvent. ).

8). Average particle diameter The film is made into ultra-thin sections of about 100 to 800 nm in the thickness direction, stained with ruthenic acid, and then transferred at a magnification of 100,000 times using a transmission electron microscope (JEM-1200EX manufactured by JEOL). However, the equivalent circle diameter was determined for 100 particles, and the average value was defined as the average particle diameter. For the core-shell type and graft copolymer type acrylic elastic particles (B), the particle size of the rubbery polymer portion was measured.

9. Heat-resistant processing suitability A hard coat layer was formed on an acrylic resin film by the following method. 90 parts by mass of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.), macromonomer AN-6S (terminal group is methacryloyl group, high molecular weight (segment) component is styrene / acrylonitrile, number average molecular weight is 6 1,000 macromonomer) (manufactured by Toagosei Co., Ltd., solid content 40 parts by mass), 20 parts by mass, photoinitiator 1-hydroxyphenyl ketone (manufactured by Ciba Specialty Chemicals Co., Ltd.), 5 parts by mass, 50 parts by mass of toluene and 50 parts by mass of methyl ethyl ketone were mixed with stirring to obtain a coating solution for forming a hard coat layer. About the center part 550mm of the film of width 570mm, it apply | coats the said coating liquid A so that the thickness after drying may be set to 5 micrometers by 3 reverse coat methods using a commercially available coater apparatus, After performing two-step drying at 80 ° C. for 30 seconds and 100 ° C. for 30 seconds under tension, the speed is 5 m / min under a high-pressure mercury lamp with an intensity of 80 W / cm set at a height of 12 cm from the coating film. And a hard coat layer was formed. The state of the running film during the formation of the hard coat layer was observed, and the heat resistance workability was determined as follows.
○: The flatness was good, and the flatness deterioration accompanied by the undulation with an amplitude of 20 mm or more and the curl on the edge part of 10 mm or more did not occur.
Δ: Deterioration of flatness accompanied by undulation with an amplitude of 20 mm or more did not occur, but curling of an edge part of 10 mm or more occurred. Alternatively, film breakage occurred at a frequency of 1/10 minutes or more.
X: The flatness deterioration accompanied by the wave | undulation of 20 mm or more of amplitude generate | occur | produced. Alternatively, film breakage occurred at a frequency of 1/10 minutes or more.

10. Film quality A hard coat layer was formed on the acrylic resin film by the above-mentioned method, the number of defects (coating missing) of the hard coat layer was visually confirmed, and evaluated according to the following criteria.
○: Defects (missing coating of hard coat layer) are 0.5 pieces / 10 cm square or less Δ: Defects are 0.5 pieces / 10 cm square or more and 1 piece / 10 cm square or less ×: Defects are 1 piece / 10 cm square or more.

[Example 1]
(1) Preparation of acrylic resin Acrylic resin (A-1)
First, a methyl methacrylate / acrylamide copolymer suspension was prepared as follows.
20 parts by weight of methyl methacrylate,
80 parts by mass of acrylamide,
0.3 parts by mass of potassium persulfate,
1500 parts by mass of ion-exchanged water was charged into the reactor, and while the reactor was replaced with nitrogen gas, the reaction was allowed to proceed at 70 ° C. until the monomer was completely converted to a polymer. The obtained aqueous solution was used as a suspending agent. A solution in which 0.05 part by mass of the above suspending agent is dissolved in 165 parts by mass of ion-exchanged water is supplied to a stainless steel autoclave having a capacity of 5 liters and equipped with a baffle and a foudra-type stirring blade, and the system is filled with nitrogen gas. It stirred at 400 rpm, replacing.
Next, a mixed substance having the following charge composition was added while stirring the reaction system.
Methacrylic acid: 27 parts by mass Methyl methacrylate: 73 parts by mass t-dodecyl mercaptan: 1.2 parts by mass 2,2′-azobisisobutyronitrile: 0.4 parts by mass The time at which the internal temperature reached 70 ° C. was set as the polymerization start time, and the polymerization was continued for 180 minutes.
Thereafter, the reaction system was cooled, the polymer was separated, washed and dried in accordance with a normal method to obtain a bead-shaped copolymer. The polymerization rate of this copolymer was 97%, and the mass average molecular weight was 130,000. 0.2% by mass of additive (NaOCH ₃ ) is blended in the above copolymer, and 10L of nitrogen is added from the hopper part using a twin screw extruder (TEX30 (manufactured by Nippon Steel Co., Ltd., L / D = 44.5)). An intramolecular cyclization reaction was carried out at a screw rotation speed of 100 rpm, a raw material supply rate of 5 kg / h, and a cylinder temperature of 290 ° C. while purging at an amount of / min., To obtain a pellet-shaped acrylic resin (A-1). The molecular weight of (A-1) was 130,000, and Tg was 140 ° C.

(2) Preparation of acrylic elastic particle Acrylic elastic particle (b-1) which is a multilayer structure polymer
In a glass container with a cooler (capacity 5 liters), as an initial adjustment solution,
120 parts by weight of deionized water,
0.5 parts by weight of potassium carbonate,
0.5 parts by weight of dioctyl sulfosuccinate,
After charging 0.005 parts by mass of potassium persulfate and stirring under a nitrogen atmosphere,
53 parts by weight of butyl acrylate,
17 parts by mass of styrene,
1 part by weight of allyl methacrylate (crosslinking agent) was charged. These mixtures were reacted at 70 ° C. for 30 minutes to obtain a rubbery polymer.
Next, 21 parts by mass of methyl methacrylate,
9 parts by weight of methacrylic acid,
A mixture of 0.005 parts by mass of potassium persulfate was continuously added over 90 minutes at 70 ° C. and held for another 90 minutes to polymerize the shell layer.
The polymer latex was coagulated with sulfuric acid, neutralized with caustic soda, washed, filtered, and dried to obtain acrylic elastic particles (b-1) as a multilayer structure polymer. The average particle size of the rubbery polymer portion of the acrylic elastic particles measured with an electron microscope was 140 nm.

(3) Blending of acrylic resin (A) and acrylic elastic particles (B) 80 parts by mass of acrylic resin (A) and 20 parts by mass of acrylic elastic particles (B) are mixed into a twin-screw extruder (Nippon Steel). TEX30, L / D = 44.5) was used and kneaded at a screw speed of 150 rpm and a cylinder temperature of 280 ° C. to obtain a pellet-shaped acrylic resin composition.

(4) Film formation After the acrylic resin composition was vacuum-dried at 80 ° C. for 8 hours, it was dissolved in methyl ethyl ketone so as to have a solid content of 30% by mass, filtered using a 1 μm cut filter, and then subjected to hopper for 24 hours. It left still and the bubble in a solution was removed. This solution is cast on a PET film through a T-die with a lip gap of 0.5 mm using a gear pump, and heat-treated in a hot air oven at 50 ° C. for 1 minute, 120 ° C. for 30 minutes, and 170 ° C. for 30 minutes. And an acrylic resin film having a thickness of 100 μm was obtained. Table 1 shows the physical properties and evaluation results of the obtained film.

[Example 2]
In Example 1, an acrylic resin film was produced in the same manner as in Example 1 except that the drying conditions for film formation were changed in three stages at 70 ° C. for 1 minute, 120 ° C. for 30 minutes, and 170 ° C. for 30 minutes. Some foaming occurred due to the high initial drying temperature. Table 1 shows the physical properties and evaluation results of the obtained film.

[Example 3]
Example 1 Example 1 except that the blending amount of the acrylic resin (A) and the acrylic elastic particles (B) was 90 parts by mass of the acrylic resin (A) and 10 parts by mass of the acrylic elastic particles (B). An acrylic resin film was prepared in the same manner as in Example 1. Table 1 shows the physical properties and evaluation results of the obtained film.

[Example 4]
In Example 1, an acrylic resin film was produced in the same manner as in Example 1 except that the acrylic elastic particles (B) were not blended. In the evaluation of heat-resistant processing suitability, the flatness was good because Tg was high, but the frequency of film tearing increased because the elongation was low. Table 1 shows the physical properties and evaluation results of the obtained film.

[Example 5]
Example 1 Example 1 except that the blending amount of the acrylic resin (A) and the acrylic elastic particle (B) was changed to 60 parts by mass of the acrylic resin (A) and 40 parts by mass of the acrylic elastic particle (B). An acrylic resin film was prepared in the same manner as in Example 1. In the heat-resistant processing suitability evaluation, the edge portion was slightly curled because of a slight decrease in Tg. Table 1 shows the physical properties and evaluation results of the obtained film.

[Comparative Example 1]
In Example 1, an acrylic resin film was prepared in the same manner as in Example 1 except that the drying conditions for film formation were changed in three stages at 80 ° C. for 1 minute, 120 ° C. for 30 minutes, and 170 ° C. for 30 minutes. Since the initial drying temperature was high, foaming occurred and the quality deteriorated. Moreover, the tear at the time of processing increased due to a fault. Table 1 shows the physical properties and evaluation results of the obtained film.

[Comparative Example 2]
In Example 1, an acrylic resin film was prepared in the same manner as in Example 1 except that the drying conditions for film formation were changed in three stages at 50 ° C. for 1 minute, 140 ° C. for 30 minutes, and 170 ° C. for 30 minutes. Foaming occurred due to the high secondary drying temperature. Table 1 shows the physical properties and evaluation results of the obtained film.

[Comparative Example 3]
Using a commercially available acrylic resin Delpet 80NH (Asahi Kasei Chemicals), a film was formed in the same manner as in Example 1. However, since the Tg of the polymer was 100 ° C., the drying conditions were changed to three stages of 50 ° C. for 1 minute, 80 ° C. for 30 minutes, and 150 ° C. for 30 minutes. Due to the low heat resistance of the film, the flatness deteriorated during the hard coat layer formation process. Table 1 shows the physical properties and evaluation results of the obtained film.

[Comparative Example 4]
The pellet-shaped acrylic resin composition of Example 1 was dried at 100 ° C. for 3 hours and extruded through a T-die (set temperature 250 ° C.) using a 65 mmφ single-screw extruder with a vent, and both sides were completely covered with a polishing roll. And cooled to obtain an acrylic resin film having a thickness of 100 μm. The obtained film had defects of 10/10 cm square or more, and the film quality evaluation was x.

  The acrylic resin film of the present invention utilizes its excellent transparency, heat resistance, light resistance, and toughness to make housings for electrical / electronic parts, optical members, automobile parts, mechanical mechanism parts, OA equipment, home appliances, etc. It can be used for various applications such as parts and general miscellaneous goods.

Claims (11)

  An acrylic resin film having a defect of 5 μm or more in diameter of 1 piece / 10 cm square or less and a glass transition temperature of 110 ° C. or more.   The acrylic resin film according to claim 1, wherein the haze is 2% or less.   3. The acrylic resin film according to claim 1, wherein the acrylic resin film has a thickness of 30 μm or more and a total light transmittance of 90% or more.   The acrylic resin film according to any one of claims 1 to 3, wherein the elongation at break is 10% or more. The acrylic resin film according to any one of claims 1 to 4, wherein the acrylic resin film comprises an acrylic resin (A) containing a glutaric anhydride unit represented by the following structural formula (1).

(In the above formula, R ¹ and R ² represent the same or different hydrogen atoms or alkyl groups having 1 to 5 carbon atoms.)   The acrylic resin (A) is composed of 50 to 90 parts by mass of an unsaturated carboxylic acid alkyl ester unit and 10 to 50 parts by mass of a glutaric anhydride unit when the acrylic resin (A) is 100 parts by mass. The acrylic resin film in any one of.   The acrylic resin film contains 5 to 50 parts by mass of acrylic elastic particles (B) having a particle diameter of 10 nm to 1000 µm with respect to 100 parts by mass of the acrylic resin film. Acrylic resin film.   2. A multilayer structure polymer in which the acrylic elastic particles (B) are composed of a layer containing one or more rubber polymers and one or more layers composed of a polymer other than the rubber polymer. The acrylic resin film in any one of -7.   The acrylic resin film according to any one of claims 1 to 8, wherein a difference in refractive index between the acrylic elastic particles (B) and the acrylic resin (A) is 0.05 or less.   The acrylic resin film according to any one of claims 1 to 9, which is produced by a solution casting method.   When the boiling point of the solvent used during solution casting is bp, initial drying is performed immediately after casting in the temperature range of (bp-40 ° C.) to bp, and when the glass transition temperature of the polymer is Tg, The manufacturing method of the acrylic resin film which performs secondary drying by Tg-50 degreeC) -Tg.