TWI586721B - An optical film manufacturing method, an optical film, and an image display device - Google Patents

Description

Optical film manufacturing method, optical film and image display device Field of invention

The present invention relates to an optical film comprising a laminate structure interposed with an adhesive layer or an adhesive layer composed of a cured layer of an adhesive composition or an adhesive composition, and a method for producing the same, at least There are first film and second film. Furthermore, the present invention relates to a liquid crystal display device, an organic EL display device, and a PDP image display device using the optical film.

Background of the invention

Liquid crystal display devices are rapidly expanding their markets in clocks, mobile phones, PDAs, notebook computers, computer monitors, DVD players, and televisions. The liquid crystal display device visualizes the polarization state by the steering of the liquid crystal, and a polarizing member can be used from the display principle. In particular, in applications such as televisions, high brightness, high contrast, and wide viewing angle are required, and high transmittance, high degree of polarization, high color reproducibility, and the like are required in polarizing films.

As a polarizing material, iodine which is most widely used, such as polyvinyl alcohol (hereinafter, simply referred to as "PVA"), adsorbs iodine and extends the structure from the viewpoint of high light transmittance and high degree of polarization. Polaroids. Generally, a polarizing film is used by dissolving a polyethylene glycol material in water. A so-called aqueous adhesive, which is a transparent protective film attached to both sides of a polarizing member. However, in recent years, active light ray hardening type resins which do not contain water or organic solvents have gradually become mainstream because of the advantages that the drying step can be omitted and the dimensional change is small.

When an optical fiber film is produced by laminating a plurality of films using an active energy ray-curable resin composition, for example, generally, an adhesive composition is applied only to the bonding surface of the transparent protective film, and since it is bonded thereto An optical film including a laminated structure is produced by laminating a polarizer or the like on the surface side. However, in the conventional production method, when a foreign material such as garbage or dust adheres to the surface of the polarizing material or the transparent protective film before the application of the adhesive composition, or the adhesive composition contains a minute foreign matter, the adhesive agent may be used. The foreign matter remains in the layer, and as a result, there is a case where an appearance defect occurs.

In the following Patent Document 1, the optical step of performing the thin coating step on the optical functional layer having a wet coating amount of 10 mL/m ² or less on the undercoat layer formed on the transparent support or on the transparent support In the method for producing a film, there is described a method for producing an optical film comprising a step of removing a foreign matter having a height of 10 μm or more from a transparent support or an undercoat layer before applying the optical functional layer.

Advanced technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2008-180905

Summary of invention

As a result of the review by the present inventors, the technique described in the above-mentioned Patent Document 1 attempts to crush foreign matter by a rolling process or the like in a state where foreign matter is present on the transparent support or the like. The removal accuracy is not high, and minute foreign matter remains after the removal step. Therefore, in fact, the technique described in the above Patent Document 1 is particularly difficult to apply to a method of manufacturing a thin optical film having a small thickness and causing an appearance defect even if a minute foreign matter is present.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing an optical film which can prevent occurrence of appearance defects due to foreign matter and/or air bubbles even if the optical film is thin.

As a result of continuous efforts to solve the above problems, the present inventors have found that when manufacturing an optical film including a laminated structure in which at least two thin films are bonded, two films are bonded to each other by a specific coating method. The adhesive surface is coated with an adhesive composition or an adhesive composition, and the removal of foreign matter and/or air bubbles and the application of the adhesive composition or the adhesive composition can be simultaneously performed. The present invention has been obtained by such efforts, and has the following constitution.

That is, the present invention relates to a method of producing an optical film comprising a laminate structure interposed with an adhesive layer or an adhesive layer composed of a cured layer of an adhesive composition or an adhesive composition, at least The first film and the second film are bonded together, and the method for producing the optical film includes a coating step, a post-use measurement coating method, and a bonding surface of the first film and a bonding surface of the second film. Both sides before coating The adhesive composition or the aforementioned adhesive composition is used to remove foreign matter and/or air bubbles.

When two films are bonded and an optical film having a laminated structure is produced, it is generally applied to one of the two films to apply an adhesive composition or an adhesive composition, and the other film is bonded thereto for production ( Hereinafter, it is also referred to as "single-side coating method"). However, in the present invention, the adhesive composition and the adhesive composition are applied to both the bonding surface of the first film and the bonding surface of the second film, and the coating method of the post-measurement coating method is used to remove foreign matter and/or This coating was carried out while the bubbles were being carried out. Specifically, the post-measurement coating method is used to scrape foreign matter such as garbage or dust existing on the bonding surfaces of the two films to be bonded, and the adhesive is scraped from the bonding surfaces of the two films. A gel or agglomerate of the composition or the adhesive composition, and an adhesive composition or an adhesive composition is applied to the bonding surfaces of both the two films. As a result, in the method for producing an optical film of the present invention, the possibility that foreign matter is present on the bonding surface of both the two films is extremely low. As a result, according to the method for producing an optical film of the present invention, an optical film which prevents occurrence of defects in appearance due to foreign matter can be produced.

On the other hand, the one-side coating method cannot remove foreign matter existing on the film bonding surface to which the adhesive composition or the adhesive composition is not applied, and therefore foreign matter remains in the adhesive layer (or adhesive layer) formed after lamination. The possibility is getting higher. Further, in the one-side coating method, the adhesive (or adhesive) coating surface of one of the films is directly contacted with the film bonding surface of the other (the adhesive composition (or the adhesive composition) is not present). fit. In this case, the adhesive composition (or adhesive composition) having a viscous contact directly contacts the other The bonding surface of one of the films makes it easy for air bubbles to enter during bonding. On the other hand, in the method of the present invention, the adhesive composition (or the adhesive composition) is applied to both the bonding surface of the first film and the bonding surface of the second film, so that the adhesive (or adhesive) of the first film is used. The coated surface is brought into contact with the coated surface of the adhesive (or adhesive) of the second film. That is, the adhesive composition (or the adhesive composition) having the viscous adhesion is overlapped with each other, so that the bubbles are hard to enter at the time of bonding, and the bubbles are easily discharged. Therefore, the method of the present invention is superior in the bubble removing effect as compared with the one-side coating method, and therefore an optical film which prevents occurrence of appearance defects due to bubbles can be produced.

In the present invention, the "post-measurement coating method" refers to a method in which an external force is applied to a liquid film to remove excess liquid, and a predetermined coating film thickness is obtained. In the method for producing an optical film of the present invention, when the external force is applied to the liquid film composed of the adhesive composition or the adhesive composition, foreign matter such as garbage or dust existing on the bonding surface can be scraped off. Specific examples of the post-measurement coating method include a gravure roll coating method, a forward roll coating method, a pneumatic blade coating method, and a rod/rod coating method, and the uniformity of removal from foreign matter or uniform coating film thickness is exemplified. From the viewpoint of the nature and the like, in the present invention, the coating method is preferably a gravure printing roll coating method using a gravure printing roll. Further, in the present invention, "removing foreign matter and/or air bubbles" means removing at least one or both of foreign matter and air bubbles.

In the above production method, the post-measurement coating method is a method in which the adhesive composition or the adhesive composition is circulated and coated, and preferably has a foreign matter removing function, and is applied from the first film and/or the first 2 the film is mixed with the foreign matter composition or the foreign matter composition of the adhesive composition, The aforementioned adhesive composition or adhesive composition is removed. In the post-measurement coating method, a coating liquid composed of an adhesive composition or an adhesive composition is applied to a bonding surface of a first film and a second film, and the coating liquid is applied from the first film and/or the first film. 2 The foreign matter removed by the bonding surface of the film may have a high possibility that the foreign matter exists on the bonding surface of the first film and the second film after application. However, the coating method to be used includes a foreign matter removing function, and a foreign matter in which the first film and/or the second film are mixed into the adhesive composition or the adhesive composition is applied from the adhesive composition or In the case where the adhesive composition is removed, the amount of foreign matter in the coating liquid can be remarkably reduced. Therefore, the possibility that foreign matter is present on the bonding surface of the first film and the second film after application can be remarkably reduced.

In the above manufacturing method, the direction of rotation of the gravure printing roll is preferably opposite to the traveling direction of the first film and the second film. In this case, the effect of foreign matter such as garbage or dust existing on the bonding surface of the first film and the bonding surface of the second film is scraped off, and the gel from the adhesive composition or the adhesive composition is scraped off. The effect of the substance or agglomerate is effectively improved, and the appearance defects of the finally obtained optical film can be more effectively prevented.

On the surface of the aforementioned gravure roll, various patterns can be formed, for example, a honeycomb-shaped mesh pattern, a trapezoidal pattern, a lattice pattern, a pyramid pattern or a diagonal line pattern can be formed. In order to effectively prevent the appearance of defects in the finally obtained optical film, the pattern formed on the surface of the aforementioned gravure roll is preferably a honeycomb-like mesh pattern. In the case of a honeycomb-like mesh, in order to improve the surface accuracy of the coated surface after applying the adhesive composition or the adhesive composition, the mesh pit volume is preferably 1 to 5 cm ³ /m ² and is 2 to 3 cm ³ /m ^{2 .} It is better. Similarly, in order to improve the surface accuracy of the coated surface after application of the adhesive composition or the adhesive composition, the number of craters per inch of the roll is preferably from 200 to 3,000 lines/inch. Further, the rotation speed ratio of the gravure printing roll is preferably from 100 to 300% with respect to the traveling speed of the first film and the second film.

The thicker the thickness of the agent layer (or the adhesive layer) and the total thickness of the optical film, the less likely the foreign matter is to be found, and the more difficult it is to be considered as a defect in appearance. On the other hand, the thinner the thickness of the adhesive layer (or the adhesive layer), the thinner the total thickness of the optical film, and the more easily the foreign matter is found, and as a result, the appearance defect becomes a problem. However, since the optical film manufacturing method of the present invention can produce an optical film having an extremely low incidence of foreign matter in the adhesive layer (or the adhesive layer), the production of the polarizing film which is particularly required for thinning in the optical film can be produced. Specifically, in the case where the first film is a transparent protective film and the second film is a polarizer, the production method of the present invention is particularly useful. In the manufacturing method of the present invention, for example, in the case where the thickness of the polarizing member is 10 μm or less, particularly in the case of manufacturing a thin polarizing film, it is possible to prevent the occurrence of foreign matter or bubbles in the adhesive layer (or the adhesive layer). A thin polarizing film having a defective appearance is preferred.

Further, the present invention relates to an optical film produced by any of the above-described manufacturing methods, and an image display device using the optical film described above.

The method for producing an optical film of the present invention can efficiently remove foreign matter present on the bonding surface of both of the two films to be bonded, and foreign matter present in the adhesive composition or the adhesive composition, and can be prevented The bubbles are mixed into the adhesive layer or in the adhesive layer, so that it can be manufactured to prevent the occurrence of An optical film having defects in the appearance of foreign matter and/or bubbles. Therefore, the method for producing an optical film of the present invention is a method for producing an optical film having a thinner thickness of an adhesive layer which is particularly resistant to an appearance defect caused by a foreign matter, and an optical film having a relatively small total thickness, particularly a thin polarizing film. Especially effective.

1‧‧‧1st film

2‧‧‧2nd film

3‧‧‧Binder composition

4‧‧‧gravure printing roller

5‧‧‧ Container

6‧‧‧ storage tank

7‧‧‧Filter

8‧‧‧ pump function

9‧‧‧Pressing roller

10‧‧‧ Gravure printing roller coating method

Fig. 1 is a schematic view showing an example of a method for producing an optical film of the present invention.

Fig. 2 is a schematic view showing an example of a gravure printing roll coating method as a post-measurement coating method used in the present invention.

Form for implementing the invention

Hereinafter, a method of producing the optical film of the present invention will be described with reference to the drawings.

The method for producing an optical film of the present invention comprises a coating step of applying a binder composition or an adhesive composition to both the bonding surface of the first film and the bonding surface of the second film, and applying the coating method. foreign matter.

Fig. 1 is a schematic view showing an example of a method for producing an optical film of the present invention. In the present embodiment, an example in which an adhesive composition is applied by a gravure roll coating method as a post-measurement coating method is shown. In Fig. 1, the first film 1 is applied to the step of applying the adhesive composition 3 by the gravure roll coating method 10, and is transported to the right in Fig. 1, and the intaglio plate provided by the gravure coating method 10 is provided. The printing roller rotates in a clockwise direction. That is, the direction of rotation of the gravure roll is opposite to the direction of travel of the first film. Similarly, in the relationship between the second film 2 and the gravure printing roll, the direction of rotation of the gravure printing roll and the traveling direction of the second film 2 are also reversed. In this case, foreign matter such as garbage or dust existing on the bonding surface of the first film 1 and the bonding surface of the second film 2 is scraped off, and the effect of the gel or agglomerate from the adhesive composition is also obtained. Effectively improved, the appearance defects of the finally obtained optical film can be more effectively prevented.

In order to effectively prevent appearance defects of the finally obtained optical film, the rotational speed of the gravure printing roll is preferably 100 to 300% with respect to the traveling speed of the first film 1 and the second film 2, and preferably 150 to 250%.

2 is a schematic view showing an example of a gravure printing roll coating method as a post-measurement coating method used in the present invention, and particularly shows a case where the adhesive composition 10 is applied to the first film 1 by using the gravure coating method 10. As shown in FIG. 2, when the foreign matter is removed while pressing the gravure printing roll 4 on the first film 1, foreign matter such as garbage or dust existing on the bonding surface of the first film 1 can be removed more effectively, and A gel or agglomerate of the composition of the agent.

As shown in FIG. 2, the gravure coating method 10 is provided with at least the gravure printing roll 4. On the surface of the gravure printing roll, a concave-convex pattern such as a honeycomb-shaped mesh pattern, a trapezoidal pattern, a lattice pattern, a pyramid pattern, or a diagonal line pattern is formed. In order to improve the surface precision of the coated surface after application of the adhesive composition or the adhesive composition, it is preferable to form a honeycomb-shaped mesh pattern, and the mesh pit volume is preferably 1 to 5 cm ³ /m ² and 2 to 3 cm ³ / m ^{2 is} preferred. Similarly, in order to improve the surface precision of the coated surface after application of the adhesive composition or the adhesive composition, the number of craters per inch of the roller should be 200 to 3000 lines/inch. The uneven pattern of the gravure printing roll 4 has a function of applying the adhesive composition 3 to the bonding surface of the first film while scraping the adhesive composition (coating liquid) 3. In the present invention, in order to prevent foreign matter from being mixed into the adhesive composition 3, the adhesive application liquid is preferably a closed system which is not exposed to the air.

In the example shown in Fig. 2, foreign matter present on the bonding surface of the first film 1 at the time of coating, and a gel or agglomerate from the adhesive composition 3 are scraped off by the gravure printing roll 4. It moves to the container 5 containing the adhesive composition 3, and is applied to the bonding surface of the first film again by the gravure printing roll 4. Therefore, particularly in the case where the post-measurement coating method is a method of circulating the adhesive composition or the adhesive composition, the elapsed time with the coating step of the adhesive composition 3 is longer by the gravure printing roller 4 The doubt that the amount of accumulated foreign materials such as scraped will increase. However, the foreign matter removing function provided in the gravure coating method 10 and the foreign matter composition or the adhesive composition which are obtained by mixing the first film and/or the second film with the adhesive composition or the adhesive composition are applied. In the case of removal, the amount of foreign matter or the like present in the adhesive composition 3 to be coated can be often kept to a very small amount or even zero. Therefore, at the end, the amount of occurrence of foreign matter or the like on the bonding surface of the first film 1 can be reduced to an extremely low level. In the present invention, examples of the foreign matter removing function include a filter, a distillation apparatus, and centrifugation. When the filter is used as the foreign matter removing function, as shown in FIG. 2, for example, the filter 7 can be disposed on the downstream side of the pump function 8. Further, the filter 7 may be disposed on the upstream side of the pump function 8, the number of which is not limited. The size of the mesh of the filter 7 can be appropriately changed depending on the material of the first film 1 and the second film or the composition of the adhesive composition 3, but it is preferably 10 μm or less, and preferably 5 μm or less. Next, the composition 3 is used as shown in FIG. 2, and can be circulated or borrowed. The adhesive composition 3 after application by the gravure printing roll 4 is discarded.

As shown in FIG. 1 , after applying the adhesive composition 3 to both the bonding surface of the first film 1 and the bonding surface of the second film 2 by the coating method of the post-measurement coating method, for example, the nip roll 9 is used. 1 The film 1 and the second film 2 are bonded together via an adhesive composition (adhesive layer).

In the case of producing an optical film on a continuous production line, the line speed of the first film and/or the second film varies depending on the hardening time of the adhesive composition (or the adhesive composition), and is preferably 1 to 500 m/min. It is preferably 5~300m/min, more preferably 10~100m/min. In the case where the line speed is too slow, the productivity is lacking, or the damage to the first film and/or the second film is too large, and an optical film which can pass the durability test cannot be produced. In the case where the line speed is too fast, there is a case where the curing of the adhesive composition is insufficient, and the adhesion of the target cannot be obtained.

Next, an optical film produced by the production method of the present invention will be described below. The optical film includes a laminate structure in which at least a first film and a second film are bonded to each other via an adhesive layer or an adhesive layer composed of a cured layer of an adhesive composition or an adhesive composition.

<Binder layer or adhesive layer>

The adhesive layer or the adhesive layer is not particularly limited as long as it is optically transparent, and various forms such as water, solvent, hot melt, and radical hardening can be used. When a transparent conductive laminated body or a polarizing film is produced as an optical film, a transparent hardening type adhesive layer is suitable.

<Transparent hardening type adhesive layer>

Formation of a transparent hardening type adhesive layer as an adhesive composition, for example It is suitable to use a radical hardening type adhesive. An active energy ray-curable adhesive such as an electron beam curing type or an ultraviolet curing type is exemplified as the radical curing type adhesive. In particular, an active energy ray hardening type which can be hardened in a short time is preferable, and an ultraviolet curable adhesive which can be hardened by low energy is preferable.

The ultraviolet curable adhesive can be roughly classified into a radical polymerization curing type adhesive and a cationic polymerization type adhesive. Further, the radical polymerization curing adhesive can also be used as a thermosetting adhesive.

Examples of the curable component of the radical curing adhesive include a compound having a (meth)acryl fluorenyl group and a compound having a vinyl group. As the curable component, any of a monofunctional group or a difunctional group can be used. Further, these curable components may be used alone or in combination of two or more. As such a curable component, for example, a compound having a (meth) acrylonitrile group is suitable.

Specific examples of the compound having a (meth) acrylonitrile group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl. (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, secondary butyl (meth) acrylate, tertiary butyl (meth) acrylate, n-pentyl (meth) acrylate, tertiary pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-Dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl (meth) acrylate, n-octadecyl (meth) acrylate, etc. (methyl) Acrylic acid (carbon number 1-20) alkyl esters.

Further, examples of the compound having a (meth)acryl fluorenyl group include a cycloalkyl (meth) acrylate (for example, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.) , an aralkyl (meth) acrylate (for example, benzyl (meth) acrylate, etc.), a polycyclic (meth) acrylate (for example, 2-isodecyl (meth) acrylate, 2 -norbornylmethyl (meth) acrylate, 5-northene-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate Etc.), containing hydroxyl (meth) acrylates (eg, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropyl methyl-butyl (Methyl) methacrylate), alkoxy- or phenoxy (meth) acrylates (for example, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl ( Methyl) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, benzene Oxyethyl (meth) acrylate, etc.), containing epoxy (meth) acrylates (eg, epoxy propyl (A) (Acrylate, etc.), halogen-containing (meth) acrylates (for example, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethylethyl (A) Acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptafluorodecyl (meth) acrylate, etc. And an alkylaminoalkyl (meth) acrylate (for example, dimethylaminoethyl (meth) acrylate, etc.), etc.

Further, examples of the compound having a (meth) acrylonitrile group other than the above include hydroxyethyl acrylamide, N-methylol acrylamide, N-methoxymethyl propylene amide, and N- An anthranyl group-containing monomer such as ethoxymethyl acrylamide or (meth) acrylamide. Acryl-based rifampin Such as nitrogen-containing monomers and the like.

In addition, as the curable component of the radical polymerization-curable adhesive, a compound having a plurality of polymerizable double bonds such as a (meth)acryl fluorenyl group or a vinyl group can be exemplified, and the compound can be mixed as a crosslinking component to Subsequent ingredients. Examples of the curable component to be such a crosslinking component include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, and cyclic trimethylol group. Propane down-form acrylate, dioxane ethylene glycol diacrylate, ethylene oxide modified diglycerin tetraacrylate, ARONIX M-220 (manufactured by Toagosei Co., Ltd.), LIGHTACRYLATE 1, 9ND-A (Kyoeisha) Manufactured by Chemical Co., Ltd., LIGHTACRYLATE DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), LIGHTACRYLATE DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Co., Ltd.), CD-536 (manufactured by Sartomer Co., Ltd.), and the like. Further, if necessary, various epoxy (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, or various (meth) acrylate monomers may be mentioned.

The radical polymerization hardening type adhesive contains the above-mentioned curable component, but a radical polymerization initiator is added in addition to the above-mentioned components depending on the type of hardening. In the case where the above-mentioned adhesive is used as an electron beam curing type, it is not necessary to particularly include the above-mentioned adhesive containing a radical polymerization initiator, but in the case of using an ultraviolet curing type or a thermosetting type, radical polymerization can be used. Starting agent. The amount of the radical initiator to be used is usually from 0.1 to 10 parts by weight, preferably from 0.5 to 3 parts by weight, per 100 parts by weight of the curable component. In addition, a radical polymerization initiator may also be added with a carbonyl group as necessary. A compound such as a compound enhances the photosensitizer based on the hardening speed or sensitivity of the electron beam. The amount of the photosensitizer used is usually from 0.001 to 10 parts by weight, preferably from 0.01 to 3 parts by weight, per 100 parts by weight of the curable component.

The curable component of the cationic polymerization hardening type adhesive is a compound having an epoxy group or an oxetane group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used. Examples of suitable epoxy compounds include compounds having at least two epoxy groups and at least one aromatic ring in the molecule, or at least two epoxy groups in the molecule, and at least one of them is constituted. a compound formed between two adjacent carbon atoms of the alicyclic ring.

In addition, a transparent hardening type adhesive layer is formed, and examples of the aqueous hardening type adhesive include ethylene polymers, gelatins, vinyl latexes, polyurethanes, isocyanates, polyesters, and the like. Epoxy and the like. The adhesive layer composed of such an aqueous binder may be formed as a coating dry layer of an aqueous solution or the like, and when preparing an aqueous solution thereof, a crosslinking agent or other additives, an acid or the like may be blended as necessary.

As the aqueous binder, an adhesive containing an ethylene-containing polymer or the like is preferably used, and as the ethylene polymer, a polyvinyl alcohol-based resin is preferred. Further, as the polyvinyl alcohol-based resin, an adhesive containing a polyvinyl alcohol-based resin having an ethyl acetate group is preferable from the viewpoint of improving durability. Further, as the crosslinking agent which can be blended into the polyvinyl alcohol-based resin, a compound having at least two functional groups reactive with the polyvinyl alcohol-based resin is preferably used. For example, boric acid or borax, a carboxylic acid compound, and an alkyl diamine can be mentioned; Isocyanates; epoxys; monoaldehydes; dialdehydes; amine-formaldehyde resins; and divalent metals, or salts of trivalent metals and oxides thereof.

The adhesive for forming the above-mentioned curable adhesive layer may be one which may contain a suitable additive if necessary. Examples of the additive include a coupling agent such as a decane coupling agent and a titanium coupling agent; an adhesion promoter typified by ethylene oxide; an additive which enhances the wettability of the transparent film, and an acryl oxide compound or a hydrocarbon. Classes (natural, synthetic resins), etc. are additives, ultraviolet absorbers, anti-aging agents, dyes, processing aids, ion trapping agents, antioxidants, adhesives, fillers (such as mechanical strength or processability) Stabilizers other than metal compound fillers, plasticizers, leveling agents, antifoaming agents, antistatic agents, heat stabilizers, hydrolysis resistance stabilizers, etc.

Further, the thickness of the transparent curable adhesive layer is preferably from 0.01 to 10 μm. It is preferably 0.1 to 5 μm, and more preferably 0.3 to 4 μm. Further, since the height difference between the respective film layers due to the appearance defect of foreign matter or bubbles is generally several μm (about 2 to 5 μm), when the thickness of the adhesive layer is 2 μm or less, the problem of appearance defects becomes serious. However, since the method for producing an optical film of the present invention can prevent appearance defects, it is particularly useful as a method for producing an optical film having an adhesive layer thickness of 2 μm or less.

The aforementioned adhesive layer is formed from an adhesive. As the adhesive, various adhesives can be used, and examples thereof include a rubber-based adhesive, an acrylic adhesive, a polyoxygen-based adhesive, an urethane-based adhesive, a vinyl alkyl ether adhesive, and polyvinylpyrrolidine. Ketone adhesives, polypropylene guanamine adhesives, cellulose adhesives, and the like. The adhesive base polymer is selected in accordance with the type of the aforementioned adhesive. Even in the aforementioned adhesives, it is suitable from the display The adhesive property of wettability, aggregability, and adhesion is excellent in weather resistance and heat resistance, and an acrylic adhesive is suitably used.

The radical polymerization hardening type adhesive can be used in the form of an electron beam curing type or an ultraviolet curing type.

In the electron beam curing type, the irradiation conditions of the electron beam may be any suitable conditions as long as the conditions for curing the radical curable adhesive composition are cured. For example, in the case of electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, more preferably 10 kV to 250 kV. In the case where the accelerating voltage is less than 5 kV, there is a concern that the electron beam does not reach the adhesive and the hardening is insufficient. If the accelerating voltage exceeds 300 kV, the penetration of the penetrating sample is too strong, and there is a pair of transparent protective film or polarizing member. Suspicion of injury. The irradiation line amount is 5 to 100 kGy, more preferably 10 to 75 kGy. When the amount of the irradiation line is less than 5 kGy, the adhesive is insufficiently hardened. If it exceeds 100 kGy, the transparent protective film or the polarizing member is damaged, and the mechanical strength is lowered or yellowed, and predetermined optical characteristics cannot be obtained.

The electron beam irradiation is usually carried out in an inert gas, but it may be carried out in the atmosphere or with a small amount of oxygen if necessary. According to the material of the transparent protective film, by appropriately introducing oxygen, it is intended that the surface of the transparent protective film to which the electron beam is initially irradiated generates oxygen barrier, which can prevent damage to the transparent protective film, and can efficiently irradiate the electron beam only to the adhesive.

On the other hand, in the ultraviolet curing type, when a transparent protective film that imparts ultraviolet absorbing energy is used, since light having a short wavelength of about 380 nm is absorbed, light having a shorter wavelength than 380 nm does not reach the active energy ray hardening type adhesive. The composition does not help its polymerization. Again, because The light system of a short wavelength of 380 nm which is absorbed by the transparent protective film is converted into heat, and the transparent protective film itself generates heat, which causes defects such as curling and wrinkles of the polarizing film. Therefore, in the case where the ultraviolet curable type of the present invention is used, it is preferable to use a device which does not emit light having a shorter wavelength than 380 nm as the ultraviolet generating device, and more specifically, the integrated illuminance and wavelength range in the wavelength range of 380 to 440 nm. The ratio of the cumulative illuminance of 250 to 370 nm is preferably 100:0 to 100:50, and preferably 100:0 to 100:40. As the ultraviolet light which satisfies the relationship of such cumulative illuminance, it is preferable to use a metal halide lamp filled with gallium and an LED light source having a wavelength range of 380 to 440 nm. Alternatively, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, incandescent bulb, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excimer laser or The sunlight is used as a light source, and the light having a short wavelength of 380 nm is shielded by a pass filter.

The first film and/or the second film can be used as long as it is a transparent optical film, and is not particularly limited. As described above, the thicker the thickness of the adhesive layer (or the adhesive layer) and the total thickness of the optical film, the less likely the foreign matter is found, and the more difficult it is to be regarded as an appearance defect problem. On the other hand, the thinner the thickness of the adhesive layer (or the adhesive layer), the thinner the total thickness of the optical film, and the more easily the foreign matter is visually recognized, and as a result, the appearance defect becomes a problem. However, the method for producing an optical film of the present invention can produce an optical film having an extremely low incidence of foreign matter in an adhesive layer (or an adhesive layer), and therefore, a method for producing a polarizing film which is particularly required for thinning in an optical film Specifically, in the case where the first film is a transparent protective film and the second film is a polarizer, the production method of the present invention is particularly useful. The system of the invention In the case where the thickness of the polarizing member is 10 μm or less, particularly in the case of manufacturing a thin polarizing film, it is possible to prevent occurrence of appearance defects due to foreign matter or bubbles in the adhesive layer (or the adhesive layer). A thin polarizing film is preferred.

The first film and/or the second film may be subjected to surface modification treatment before applying the active energy ray-curable adhesive composition. Specific treatments include treatment by corona treatment, plasma treatment, and saponification treatment.

Further, in the method for producing an optical film of the present invention, the first film and the second film are preferably laminated via an adhesive layer formed of a cured layer of the radical polymerization-curable adhesive composition, and the first film and the first film are bonded to each other. 2 Between the films, an easy-to-attach layer can be provided. The easy-adhesion layer can be formed, for example, by various resins having a polyester skeleton, a polycarbonate skeleton, a polyurethane skeleton, a polyfluorene oxide, a polyamine skeleton, a polyimine skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins may be used alone or in combination of two or more. In addition, other additives may be added to the formation of the easy-to-adhere layer. Specifically, a stabilizer such as an adhesive, an ultraviolet absorber, an antioxidant, or a heat stabilizer may be further used.

The formation of the easy-adhesion layer is carried out by coating and drying the film of the easy-adhesion layer on the film by a known technique. The material for forming the easy-adhesion layer is a solution which is diluted to an appropriate concentration in consideration of the thickness after drying and the smoothness of coating, and is generally adjusted. The thickness of the easy-adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and more preferably 0.05 to 1 μm. In addition, the easy layer can be set with multiple layers, in this case, The total thickness of the easy-to-adhere layer is also preferably within the above range.

Hereinafter, a polarizing film will be described as an example of an optical film. The polarizing film including at least the laminated structure of the first film and the second film is bonded, and as shown in FIG. 1, the first film 1 and the laminate layer can be bonded by an adhesive layer formed of an adhesive composition. In the case of the film 2, the first film 1 is a transparent protective film, and the second film 2 is laminated on a transparent protective film, a PET substrate or the like, and a polarizer is laminated on the adhesive layer as needed. In the example shown in the embodiment, the polarizer surface of the second film 2 is laminated as a bonding surface, and an adhesive composition is applied to the bonding surface.

The production method of the present invention can produce an optical film which is effective for preventing foreign matter from occurring in the adhesive layer, and is therefore suitable for producing an optical film which is caused by a defect in appearance of a foreign matter, which is a serious problem, in particular, a thin thickness. Therefore, the thickness of the first film and the second film (in the present embodiment, the first film is a protective film, and the second film is a laminated film of a PET substrate + a polarizer) is preferably 60 μm or less, and preferably 40 μm or less. In addition, when the total thickness of the polarizing film is 100 μm or less, since the thickness is small, appearance defects such as foreign matter due to the adhesive layer are often problematic. However, the optical film which is effective for preventing foreign matter from occurring in the adhesive layer can be produced by the production method of the present invention, and is therefore suitable for the case of producing a thin polarizing film having a total thickness of 100 μm or less, and is particularly suitable for producing a thin film having a total thickness of 50 μm or less. The case of a polarizing film. In the case of producing a thin polarizing film of the present invention, in particular, in the case of producing a thin polarizing film comprising a thin polarizing member having a thickness of 10 μm or less, the occurrence of appearance defects can be effectively prevented.

The polarizing member is not particularly limited, and various types can be used. As a bias The light member may, for example, be a hydrophilic polymer film such as a polyvinyl alcohol film, a partially acetalized polyvinyl alcohol film, or an ethylene/vinyl acetate copolymer partially saponified film, and adsorb iodine or a dichroic dye. The dichroic material is subjected to uniaxial stretching, a polyhydric alcohol or a dehydrated material, or a polychlorinated oriented film such as a polyvinyl chloride dehydrochlorinated product. Even in these cases, a polarizer comprising a polyvinyl alcohol film and a dichroic material such as iodine is suitable. The thickness of these polarizers is not particularly limited, and is generally about 80 μm or less.

The polarizer in which the polyvinyl alcohol-based film is uniaxially stretched by iodine dyeing can be produced, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine, and stretching it to 3 to 7 times the original length. It may also be immersed in an aqueous solution of boric acid or potassium iodide as necessary. Further, it is also necessary to immerse the polyvinyl alcohol film in water for washing before the dyeing. By washing the polyvinyl alcohol film with water, in addition to washing off the dirt or anti-caking agent on the surface of the polyvinyl alcohol film, it is also possible to prevent unevenness in dyeing unevenness due to swelling of the polyvinyl alcohol film. The stretching can also be carried out after dyeing with iodine, or at the same time as dyeing, or by iodine after stretching. Stretching can also be carried out in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Further, as the polarizing member, a thin polarizing member having a thickness of 10 μm or less can be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. Such a thin polarizer has an advantage of being small in thickness, excellent in visibility, and small in dimensional change, so that the durability is excellent, and the thickness of the polarizing film is also reduced.

For example, Japanese Laid-Open Patent Publication No. SHO-51-069644, JP-A-2000-338329, and the like. A thin polarizer described in the specification of WO2010/100917, the specification of PCT/JP2010/001460, or the specification of Japanese Patent Application No. 2010-269002, or the specification of Japanese Patent Application No. 2010-263692. Such a thin polarizer can be obtained by a step of stretching a layer of a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) and a resin substrate for stretching in a layered state, and a method of performing the dyeing step. obtain. According to this method, even if the PVA-based resin layer is thin, it can be stretched by being supported by the resin substrate for stretching without causing problems such as breakage due to stretching.

As the thin polarizing member, even in the method of including the step of stretching in the state of the laminated body and the step of performing the dyeing, in the case of being able to stretch at a high magnification and improving the polarizing performance, for example, WO2010/100917 pamphlet, PCT/ It is preferable to obtain the method of the step of stretching in an aqueous solution of boric acid described in the specification of JP 2010/001460, or the specification of Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692, especially by The method described in the specification of Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692, which is included in the method of assisting in-line stretching before stretching in an aqueous solution of boric acid is preferred.

The thin high-function polarizer described in the above-mentioned specification of PCT/JP2010/001460 is a thin high-function having a thickness of 7 μm or less which is formed by a PVA-based resin which is formed by laminating a resin substrate and is oriented by a dichroic material. The polarizer has optical characteristics of a single transmittance of 42.0% or more and a degree of polarization of 99.95% or more.

The above thin high-function polarizer can be carried out by the following means A PVA-based resin layer is produced by coating and drying a PVA-based resin on a resin substrate having a thickness of at least 20 μm, and the formed PVA-based resin layer is immersed in a dyeing liquid of a dichroic substance to cause a dichroic substance to be The PVA-based resin layer is adsorbed to the PVA-based resin layer, and the PVA-based resin layer in which the dichroic substance is adsorbed is stretched in a boric acid aqueous solution to be integrated with the resin substrate so that the total stretching ratio is five times or more the original length.

Further, a method of manufacturing the above-described thin high-function polarizer, which is a method for producing a laminate film comprising a thin high-functional polarizer for orienting a dichroic substance, comprising the steps of: forming a resin group containing a thickness of at least 20 μm And a step of forming a laminate film of a PVA-based resin layer by coating and drying an aqueous solution containing a PVA-based resin on one side of the resin substrate; by including the resin substrate and forming a single side of the resin substrate The laminate film of the PVA-based resin layer is immersed in a dyeing liquid containing a dichroic material, and a step of adsorbing a dichroic material in a PVA-based resin layer contained in the laminate film; and containing a dichroic substance; The laminate film of the PVA-based resin layer is stretched in a boric acid aqueous solution to a total stretching ratio of 5 times or more of the original length; and the PVA-based resin to which the dichroic substance is adsorbed is integrated with the resin substrate. The film is formed by stretching a PVA-based resin layer having a dichroic material oriented on one side of the resin substrate, and has a thickness of 7 μm or less and a single transmittance of 42.0% or more. Step laminate film polarization degree of 99.95% or more characteristics of the optical thin highly-functional polarizing member.

In the above-mentioned Japanese Patent Application No. 2010-269002 or Japanese Patent Application No. 2010-263692, a thin polarizing member is used for the dichroic substance. A continuous wave polarizer comprising an oriented PVA-based resin, which comprises a layered body comprising a PVA-based resin layer formed on a non-crystalline ester-based thermoplastic resin substrate by air-assisted stretching and boric acid water The two-stage stretching step consisting of stretching is carried out to obtain a thickness of 10 μm or less. Such a thin polarizer is formed to have a single transmittance of T and a degree of polarization of P, and has a P>-(100.929T-42.4-1)×100 (however, T<42.3), and P≧ The optical characteristics of the 99.9 (but, T≧42.3) conditions are preferred.

Specifically, the thin polarizing member can be manufactured by a manufacturing method of a thin polarizing member comprising the following steps. The steps are as follows: by stretching the PVA-based resin layer of the amorphous ester-based thermoplastic resin substrate formed on the continuous wave in the air at a high temperature to form an intermediate formation of the stretched PVA-based resin layer. a step of adsorbing a dichroic substance by stretching the intermediate product to form a colored intermediate product composed of a PVA-based resin layer oriented with a dichroic substance (preferably a mixture of iodine or iodine and an organic dye) The step of stretching the colored intermediate product into boric acid water to form a polarizer having a thickness of 10 μm or less composed of a PVA-based resin layer orienting the dichroic substance.

In the production method, the total stretching ratio of the PVA-based resin layer formed on the amorphous thermoplastic resin substrate in the air at a high temperature stretching and boric acid water stretching is desirably five times or more. The liquid temperature of the boric acid aqueous solution which is stretched in boric acid water may be 60 ° C or more. In the case where the colored intermediate product is stretched in the aqueous boric acid solution, it is desirable to carry out the insolubilization treatment on the colored intermediate product. In this case, it is desirable to immerse the colored intermediate product in a boric acid aqueous solution having a liquid temperature of not more than 40 ° C. . Above The amorphous ester thermoplastic resin substrate may be a polyethylene terephthalate copolymer containing copolymerized isophthalic acid or polyethylene terephthalate copolymerized with cyclohexane dimethanol Ester copolymer or other polyethylene terephthalate copolymer amorphous polyethylene terephthalate, preferably made of a transparent resin, the thickness of which can be a film-formed PVA resin More than 7 times the layer thickness. Further, the stretching ratio in the high-temperature stretching in the air is preferably 3.5 times or less, and the stretching temperature in the high-temperature stretching in the air is preferably a glass transition temperature of the PVA-based resin or more, specifically, in the range of 95 ° C to 150 ° C. In the case of performing high-temperature stretching in the air by uniaxial stretching at the free end, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is 5 times or more and 7.5 times. The following is better. In the case where the high-temperature stretching in the air is carried out by uniaxial stretching at a fixed end, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is 5 times or more. 8.5 times or less is preferred.

More specifically, a thin polarizer can be manufactured by the following method.

A continuous wave substrate of an isophthalic acid-polyethylene terephthalate (amorphous PET) copolymer in which isonononic acid was copolymerized at a percentage of 6 moles was produced. The glass transition temperature of the amorphous PET was 75 °C. A laminate comprising a continuous wave amorphous PET substrate and a polyvinyl alcohol (PVA) layer was produced as follows. In addition, the glass transition temperature of PVA was 80 °C.

A 200 μm thick amorphous PET substrate was prepared, and a PVA powder having a polymerization degree of 1,000 or more and a saponification degree of 99% or more was dissolved in a PVA aqueous solution having a concentration of 4 to 5% in water. Next, a PVA aqueous solution was applied to a 200 μm thick amorphous PET substrate, and dried at a temperature of 50 to 60 ° C to obtain an amorphous property. The PET substrate was formed into a laminate of a 7 μm thick PVA layer.

A laminate of a 7 μm thick PVA layer was subjected to the following steps of a two-stage stretching step including air-assisted stretching and boric acid water stretching to produce a thin high-functionality polarizer having a thickness of 3 μm. The laminate comprising a 7 μm-thick PVA layer was integrally molded with an amorphous PET substrate by an air-assisted stretching step in the first stage to form a stretched laminate including a PVA layer having a thickness of 5 μm. Specifically, in the stretched laminate, a laminate including a 7 μm-thick PVA layer was placed in a stretching apparatus equipped in an oven set to a temperature of 130 ° C in a stretching temperature environment so that the stretching ratio was 1.8 times. Free end uniaxial tensioner. By this stretching treatment, the PVA layer containing the stretched laminate was changed to a PVA layer of 5 μm thick in which the PVA molecules were oriented.

Next, by the dyeing step, a colored layered body in which iodine is adsorbed to a 5 μm-thick PVA layer in which PVA molecules are oriented is formed. Specifically, the coloring layered body is a dyeing liquid containing iodine and potassium iodide at a liquid temperature of 30 ° C, so that the single transmittance of the PVA layer constituting the finally produced high-function polarizing member is 40 to 44%. The stretched laminate is immersed for any time to adsorb iodine to the PVA layer containing the stretched laminate. In this step, the dyeing liquid is water-based, and the iodine concentration is in the range of 0.12 to 0.30% by weight, and the potassium iodide concentration is set in the range of 0.7 to 2.1% by weight. The concentration ratio of iodine to potassium iodide is 1:7. In addition, iodine must be dissolved in water to have potassium iodide. More specifically, the stretched laminate was immersed for 60 seconds by a dyeing liquid having an iodine concentration of 0.30% by weight and a potassium iodide concentration of 2.1% by weight to form a colored layered body in which iodine was adsorbed on a 5 μm-thick PVA layer in which PVA molecules were oriented.

Furthermore, by the second stage of the boric acid water stretching step, The color laminate was integrated with the amorphous PET substrate and further stretched to form an optical film laminate including a PVA layer constituting a 3 μm-thick high-function polarizer. Specifically, the optical film laminate is a stretching apparatus provided in a treatment apparatus equipped with a boric acid aqueous solution having a liquid temperature range of 60 to 85 ° C, which is set to contain boric acid and potassium iodide, so that the stretching ratio becomes The free end uniaxial tension is performed in a 3.3-fold manner. In more detail, the liquid temperature of the aqueous boric acid solution was 65 °C. Further, the boric acid content was set to 4 parts by weight based on 100 parts by weight of water, and the potassium iodide content was set to 5 parts by weight based on 100 parts by weight of water. In this step, the colored layer body having the adjusted iodine adsorption amount is first immersed in a boric acid aqueous solution for 5 to 10 seconds. Then, the colored layered body is directly passed between the rolls of the multiple arrays having different rotation speeds of the stretching apparatus provided in the processing apparatus, and the free end uniaxial drawing is performed in such a manner that the stretching ratio is 3.3 times in a manner of 30 to 90 seconds. Stretch. By this stretching treatment, the PVA layer contained in the colored layered body was changed to the adsorbed iodine as a polyiodide ion complex which was oriented in a single direction to a higher order 3 μm thick PVA layer. This PVA layer constitutes a highly functional polarizer of an optical film laminate.

Although the steps necessary for the production of the optical film laminate are not required, the optical film integrated layer is taken out from the aqueous boric acid solution by a washing step, and washed with an aqueous solution of potassium iodide to adhere to the film formed on the amorphous PET substrate at 3 μm. Boric acid on the surface of the thick PVA layer is preferred. Then, the washed optical film laminate was dried by a drying step of warm air at 60 °C. Further, the washing step is a step of eliminating appearance defects such as boric acid precipitation.

The same steps are not necessary for the manufacture of the optical film laminate, but by the bonding and/or transfer step, the adhesive can also be applied to the film to be formed. On the surface of the 3 μm thick PVA layer of the crystalline PET substrate, after bonding the 80 μm thick triethylene fluorene cellulose film, the amorphous PET substrate was peeled off, and the 3 μm thick PVA layer was transferred to the 80 μm thick triethylene fluorene fiber. Film.

[other steps]

The above-described method of manufacturing the thin polarizing member may include other steps in addition to the above steps. As another step, for example, an insolubilization step, a crosslinking step, a drying (adjustment of moisture content) step, and the like can be given. Other steps can be made at any suitable time. The above-described insolubilization step is typically carried out by immersing the PVA-based resin layer in an aqueous boric acid solution. By performing the insolubilization treatment, the PVA-based resin layer can be imparted with water resistance. The concentration of the aqueous boric acid solution is preferably from 1 part by weight to 4 parts by weight based on 100 parts by weight of the water. The liquid temperature of the insoluble bath (aqueous boric acid solution) is preferably from 20 ° C to 50 ° C. The insolubilization step is preferably carried out after the production of the laminate, before the dyeing step or the water stretching step. The crosslinking step is typically carried out by immersing the PVA-based resin layer in an aqueous boric acid solution. By performing the crosslinking treatment, the PVA-based resin layer can be imparted with water resistance. The concentration of the aqueous boric acid solution is preferably from 1 part by weight to 4 parts by weight based on 100 parts by weight of the water. Further, in the case where the crosslinking step is carried out after the above dyeing step, it is preferred to further formulate the iodide. By dissolving the iodide, iodine elution adsorbed to the PVA-based resin layer can be suppressed. The amount of the iodide compound is preferably from 1 part by weight to 5 parts by weight per 100 parts by weight of the water. Specific examples of the iodide are as described above. The liquid temperature of the crosslinking bath (boric acid aqueous solution) is preferably from 20 ° C to 50 ° C. The crosslinking step is preferably carried out before the stretching step of the above-mentioned second boric acid water. In a preferred embodiment, the dyeing step, the crosslinking step, and the second boric acid aqueous stretching step are carried out in the order.

As a material for forming the transparent protective film provided on one surface or both surfaces of the polarizing member, it is preferable to be excellent in transparency, mechanical strength, thermal stability, moisture barrier property, and isotropic property. For example, a polyester polymer such as polyethylene terephthalate or polyethylene naphthalate, a cellulose polymer such as diethyl fluorene cellulose or triethylene fluorene cellulose, or polymethacrylic acid may be mentioned. An acrylic polymer such as a methyl ester, a styrene polymer such as polystyrene or acrylonitrile ‧ styrene copolymer (AS resin), or a polycarbonate polymer. Further, examples of the polymer forming the transparent protective film include a polyethylene, a polypropylene, a ring, a polyolefin having a norbornene structure, a polyolefin polymer such as an ethylene/propylene copolymer; and a vinyl chloride; Polymers; decylamine polymers such as nylon or aromatic polyamine; quinone imine polymers; terpene polymers; polyether fluorene polymers; polyether ether ketone polymers; polyphenylene sulfides Polymer; vinyl alcohol polymer; vinylidene chloride polymer; polyvinyl butyral polymer; polyarylate polymer; polyoxymethylene polymer; epoxy polymer; or the above polymer Blends and the like. One or more optional additives may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant, and the like. The content of the above thermoplastic resin in the transparent protective film is preferably from 50 to 100% by weight, more preferably from 50 to 99% by weight, still more preferably from 60 to 98% by weight, particularly preferably from 70 to 97% by weight. When the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the thermoplastic resin may not sufficiently exhibit the high transparency and the like which are originally possessed.

In addition, as a transparent protective film, a special Japanese patent can be cited. The polymer film described in JP-A-2001-343529 (WO01/37007), for example, contains (A) a thermoplastic resin having a substituted and/or unsubstituted quinone imine group in a branched chain; and (B) having a branch in the branch A resin composition of a thermoplastic resin substituted with and/or substituted with a phenyl group and a nitrile group. Specific examples thereof include a film containing a resin composition of an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile/styrene copolymer. As the film, a film composed of a mixed extrudate of a resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, the problem of unevenness due to warpage of the polarizing film can be eliminated, and the water vapor permeability is small, and the wettability durability is excellent.

The thickness of the transparent protective film can be appropriately determined, and it is generally about 1 to 500 μm in terms of workability and thin layer properties such as strength and operability. Especially 20~80μm is preferred, and 30~60μm is preferred.

Further, in the case where a transparent protective film is provided on both sides of the polarizer, a transparent protective film made of the same polymer material may be used, and a transparent protective film made of a different polymer material or the like may be used.

A functional layer such as a hardened layer, an antireflection layer, an anti-adhesion layer, a diffusion layer, or an anti-glare layer may be provided on the surface of the polarizer that does not follow the transparent protective film. Further, the functional layer such as the hardened layer, the antireflection layer, the anti-adhesion layer, the diffusion layer or the anti-glare layer may be provided separately from the transparent protective film itself, or may be provided separately from the transparent protective film.

The polarizing film of the present invention can be used as an optical film laminated with other optical layers when it is practical. The optical layer is not particularly limited, and for example, one or two or more reflective or semi-transmissive plates, a retardation plate (including a 1/2 or 1/4 wavelength plate), and a viewing angle compensation film can be used to form a liquid crystal. An optical layer that will be used when displaying a device or the like. In particular, in the polarizing film of the present invention, a reflective polarizing film or a semi-transmissive polarizing film which is formed by laminating a reflecting plate or a semi-transmissive plate, and an elliptical polarizing film or a circular polarizing film formed by laminating a phase difference plate on the polarizing film. It is preferable that the film is a polarizing film formed by a wide viewing angle polarizing film which is formed by recombining a viewing angle compensation film on a polarizing film, or a polarizing film is further laminated to increase a brightness film.

The optical film in which the optical layer is laminated on the polarizing film may be formed by sequentially laminating in a manufacturing process of a liquid crystal display device or the like. However, in order to form an optical film in advance, stability in quality or assembly work is performed. It is excellent and has the advantage of improving the manufacturing steps of the liquid crystal display device and the like. The laminate may use an appropriate bonding means such as an adhesive layer. In the case of the above-mentioned polarizing film or other optical film, the optical axis of the film may be appropriately arranged in accordance with the intended phase difference characteristic.

In the above-mentioned polarizing film or an optical film in which at least one polarizing film is laminated, an adhesive layer for following other components such as a liquid crystal cell may be provided. The adhesive for forming the adhesive layer is not particularly limited, and for example, an acrylic polymer, a polysiloxane polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine or a rubber may be suitably selected. The polymer is the base polymer. In particular, it is preferable to use an acrylic adhesive which is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesion properties, and is excellent in weather resistance, heat resistance, and the like.

The adhesive layer may be provided on one or both sides of the polarizing film or the optical film as an overlapping layer of different compositions or types. In addition, in the case of being disposed on both sides, the surface of the polarizing film or the optical film may not be An adhesive layer of the same composition or type or thickness. The thickness of the adhesive layer can be appropriately determined depending on the purpose of use or the adhesion, and is generally 1 to 500 μm, preferably 1 to 200 μm, particularly preferably 1 to 100 μm.

The exposed surface of the adhesive layer is temporarily adhered to the release paper for protection against contamination or the like for protection. Thereby, it is possible to prevent contact with the adhesive layer in a general treatment state. As the release paper, in addition to the above-mentioned thickness conditions, those suitable according to the conventional standards can be used, for example, a plastic film, a rubber sheet, a paper, a cloth, a non-woven fabric, a net, a foamed sheet or a metal foil, and the like, and the like. The blade is coated with a suitable stripping agent such as polyfluorene or long-chain alkyl, fluorine or molybdenum sulfide.

The polarizing film or the optical film of the present invention can be suitably used for formation of various devices such as a liquid crystal display device. The formation of the liquid crystal display device can be carried out in accordance with conventional standards. That is, the liquid crystal display device is formed by appropriately combining a liquid crystal cell with a polarizing film or an optical film, and constituting a driving circuit or the like according to a necessary illumination system, etc., but in addition to using the polarizing film or the optical film of the present invention in the present invention It is not particularly limited, and can be carried out in accordance with conventional standards. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can also be used.

A liquid crystal display device in which a polarizing film or an optical film is disposed on one side or both sides of the liquid crystal cell, or a liquid crystal display device such as a backlight or a reflector in the illumination system can be formed. In this case, the polarizing film or the optical film of the present invention may be provided on one side or both sides of the liquid crystal cell. In the case where a polarizing film or an optical film is provided on both sides, the phase may be phase The same person can also be different. Further, when forming a liquid crystal display device, for example, a suitable layer such as a diffusion plate, an anti-glare layer, an anti-reflection film, a protective plate, a ruthenium array, a lens array sheet, a light diffusion plate, and a backlight may be disposed at an appropriate position. Or 2 or more layers.

[Examples]

Hereinafter, the examples of the present invention are described, but the embodiments of the present invention are not limited thereto. In addition, the "part by weight" in the composition means the amount when the total amount of the composition is 100 parts by weight.

(1) Adjustment of the composition of the adhesive

<Adjustment of Active Energy Ray Hardening Adhesive Composition>

38.5 parts by weight of HEAA (hydroxyethyl acrylamide) [manufactured by Xingren Co., Ltd.], ARONIX M-220 (tripropylene glycol diacrylate) [manufactured by Toagosei Co., Ltd.] 20.0 parts by weight, ACMO (propylene mercapto) 38.5 parts by weight, KAYACURE DETX-S (diethyl thioxanthone) [manufactured by Nippon Kayaku Co., Ltd.] 1.5 parts by weight, IRGACURE 907 (2-methyl-1-(4-methyl) 1.5 parts by weight of phenylthio)-2-norfolinylpropan-1-one) (manufactured by BASF Corporation) was mixed and stirred at 50 ° C for 1 hour to obtain an active energy ray-curable adhesive.

<Adjustment of Polyvinyl Alcohol Adhesive Composition>

Hydroxymethyl melamine 50 with respect to 100 parts of polyvinyl alcohol-based resin having an ethyl acetonitrile group (average degree of polymerization: 1200, degree of saponification: 98.5 mole percent, degree of acetonitrile: 5 moles) The fraction was dissolved in pure water at a temperature of 30 ° C, and adjusted to an aqueous solution having a solid concentration adjusted to 3.7%. Adding colloidal alumina (average particle) to 100 parts of the aforementioned aqueous solution The sub-path was 15 nm, the solid concentration was 10%, and the positive electrode was charged with 18 parts of the aqueous solution of the adhesive.

<Organic solvent-based adhesive composition>

CEMEDINE 198L (manufactured by Cemedine Co., Ltd.) was used.

(2) Production of thin polarizer

In order to produce a thin polarizer, first, a laminate of a 24 μm-thick PVA layer formed on an amorphous PET substrate is formed into a stretched laminate by an air-assisted stretching at a stretching temperature of 130 ° C, and then a tensile laminate is formed. The coloring layer is formed by dyeing, and the colored layered body is further stretched by boric acid water having a stretching temperature of 65 ° C to form a film containing the amorphous stretching material in such a manner that the total stretching ratio is 5.94 times. An optical film laminate of a 10 μm thick PVA layer which was stretched was carried out. By such a two-stage stretching, the PVA molecules of the PVA layer formed on the amorphous PET substrate are oriented to a high order, and the iodine by dye adsorption is unidirectionally oriented as a polyiodide ion complex. The thin thin polarizer can produce an optical film laminate (second film (total thickness 40 μm)) containing a PVA layer having a thickness of 5 μm.

As the first film, a transparent protective film (thickness: 40 μm) composed of a (meth)acrylic resin having a lactone ring structure was used.

Example 1

In the production line shown in Figs. 1 and 2, a gravure coating method 10 having a gravure printing roll 4 (MCD coater (manufactured by Fuji Machinery Co., Ltd.) (mesh shape: honeycomb pattern, pit line of gravure roll) is used. Number: 1000 strips/inch, rotation speed ratio: 140%), by applying the adhesive composition 3 to both the bonding surface of the first film 1 and the bonding surface of the second film 2, removing foreign matter and bubbles At the same time, a polarizing film is produced. The second film 2 composed of the PET substrate and the thin polarizer is applied with the adhesive composition 3 so that the surface of the thin polarizer becomes the bonding surface. Further, the adhesive composition 3 was applied to the first film and the second film so that the thickness of the adhesive layer after drying became 1 μm. As the gravure roll coating method 10, a foreign matter removing function (a foreign matter removing method using a filter) shown in Fig. 2 is used.

<Active energy ray>

After passing through the production line shown in Fig. 1, an ultraviolet (gallium metal halide) irradiation device was used as the active energy ray: Light HAMMER 10 bulb manufactured by Fusion UV Systems, Inc.: V bulb maximum illuminance: 1600 mW/cm ² , cumulative irradiation amount: 1000/mJ/cm ² (wavelength: 380 to 440 nm), the adhesive composition 3 was cured to produce an optical film. In addition, the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell.

Examples 2 to 9, Comparative Examples 1 to 6

In addition to the type of the adhesive composition to which the first film and the second film are bonded, the presence or absence of the first film and/or the second film-coated adhesive composition, the type of the post-measurement coating method, and the formation of the surface of the gravure roll An optical film was produced by the same method as that of Example 1 except that it was changed to the one described in Table 1. In the bar coating method and the pneumatic blade coating method, commercially available coating devices were used.

<Method for Calculating the Number of Foreign Matter in Adhesive Agent>

The number of appearance defects (the number of appearance defects (from /m ² ) from foreign matter and from (bonding) bubbles) in the adhesive layer of the polarizing film was calculated by using a visual inspection and a reflection inspection by the automatic inspection device. The results are shown in Table 1.

[Table 1]

1‧‧‧1st film

2‧‧‧2nd film

3‧‧‧Binder composition

9‧‧‧Pressing roller

10‧‧‧ Gravure printing roller coating method

Claims (10)

A method for producing an optical film comprising a laminate structure in which an adhesive layer or an adhesive layer composed of a cured layer of an adhesive composition or an adhesive composition is bonded to at least a first film and In the second film, the method for producing an optical film includes a coating step, a post-use measurement coating method, and applying the adhesive composition to both the bonding surface of the first film and the bonding surface of the second film. Or the aforementioned adhesive composition, thereby removing foreign matter, air bubbles, or foreign matter and air bubbles. The method for producing an optical film according to claim 1, wherein the post-measurement coating method is a method of circulating the adhesive composition or the adhesive composition, and has a foreign matter removing function, which is applied by coating The first film, the second film, or the foreign material in which the first film and the second film are mixed with the adhesive composition or the adhesive composition are removed from the adhesive composition or the adhesive composition. The method of producing an optical film according to claim 1, wherein the coating method is a gravure printing roll coating method using a gravure roll. A method of producing an optical film according to claim 3, wherein a direction of rotation of said intaglio printing roll is opposite to a direction of travel of said first film and said second film. The method of producing an optical film according to claim 3, wherein the pattern formed on the surface of the gravure roll is a honeycomb pattern. The method for producing an optical film according to claim 3, wherein the first aspect is The traveling speed of the film and the second film is 100 to 300% of the rotation speed of the gravure printing roll. The method for producing an optical film according to any one of claims 1 to 6, wherein the first film-based transparent protective film and the second film-based polarizer are used. The method of producing an optical film according to claim 7, wherein the thickness of the polarizer is 10 μm or less. An optical film produced by the manufacturing method of any one of claims 1 to 8. An image display apparatus characterized by using an optical film as claimed in claim 9.