TW201323944A - Method for manufacturing polarizing plate - Google Patents

Abstract

Provided is a method for manufacturing polarizing plate formed by laminating a transparent film on one surface or two surfaces of a polarizing film, which includes the following steps in this order: an adhesive dispensing step of dispensing an active energy ray curable adhesive on one surface of the transparent film or one surface or two surfaces of the polarizing film, a laminating step of laminating the transparent film with the polarizing film by applying pressure on a laminated body with the transparent film laminated on one surface or two surfaces of the polarizing film via the adhesive, and a first active energy ray irradiating step of irradiating an active energy ray to the laminated body to cure the adhesive when the laminated body is transported with the laminated body being closely-attached to a roller rotating in a transporting direction, wherein the maximum height Ry of the surface roughness of the roller is 0.4 to 12S.

Description

Polarizing plate manufacturing method

The present invention relates to a method of manufacturing a polarizing plate used as one of optical components constituting a liquid crystal display device or the like.

In the polarizing film, a polyvinyl alcohol-based resin film is widely used to adsorb a dichroic dye, and an iodine-based polarizing film containing iodine as a dichroic dye and a dichroic direct dye as a dichroic dye are known. The dye is a polarizing film or the like. These polarizing films are generally laminated on a single surface or both surfaces thereof via a transparent film such as a triacetyl cellulose film to form a polarizing plate.

A method of laminating a single layer or both surfaces of a polarizing film by a transparent film is applied to an active energy ray-curable resin on the surface of the transparent film, and then the polarizing film and the transparent film are sandwiched by a pair of rolls (bonding rollers). In the meantime, it is bonded to the active energy ray and then hardened by the active energy ray (Patent Document 1: JP-A-2004-245925, Patent Document 2: JP-A-2009-134190, Patent Document 3) : JP-A-2011-95560).

However, in the case of the polarizing plate manufactured in this manner, the curing of the active energy ray-curable resin is not appropriate, and the entire polarizing plate is curled by waves such as waves. When a wave is generated on a polarizing plate, the appearance is not good, and when it is attached to the liquid crystal cell, it is easy to leave air bubbles on the adhesive surface to reduce the workability and become liquid crystal display. The reason why the display quality is lowered in the display device.

In the case where the active energy ray-curable resin is cured by irradiation with an active energy ray, the laminated body is adhered to the outer peripheral surface of the roller and hardened at the same time, and generation of a wave roll or the like can be suppressed.

(previous technical literature) Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-245925

Patent Document 2: Japanese Laid-Open Patent Publication No. 2009-134190

Patent Document 3: Japanese Laid-Open Patent Publication No. 2011-95560

In the step of curing the active energy ray-curable resin by irradiation with an active energy ray in a state in which the laminated body is in close contact with the outer peripheral surface of the roller, the laminated body obtained after curing (hereinafter also referred to as a polarizing plate). On the surface of the surface, there is a case where the appearance of the wave is poor (hereinafter, this state is called "wave plate undulation"). Such a surface defect, like a wave, may cause a deterioration in the quality of the liquid crystal display device due to poor appearance of the polarizing plate. SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a polarizing plate which can prevent the occurrence of wave-like undulations on the surface of a polarizing plate.

The inventors of the present invention have intensively reviewed the results of the surface defects of the polarizing plate which occurred in the active energy ray irradiation step, and found that the surface roughness of the roller used in the active energy ray irradiation step can be suppressed. The wavy undulations that occur on the surface of the polarizer.

The present invention is based on the above knowledge and is one side or both sides of the polarizing film. a method for producing a polarizing plate comprising a transparent film; the method comprising the steps of: applying an adhesive coating step of an active energy ray-curable adhesive to one surface of the transparent film; and applying the adhesive to the transparent film a step of laminating a laminated body formed on one side or both sides of a polarizing film to bond the transparent film and the polarizing film; and a state in which the laminated body is brought into close contact with the roller rotating in the conveying direction Between the transports, the first active energy ray irradiation step of irradiating the active energy rays to the laminate to cure the adhesive, wherein the maximum roughness Ry of the surface roughness of the roller is 0.4 to 12 s. The above roller is preferably a cooling roller.

According to the method for producing a polarizing plate of the present invention, wave-like undulations such as fluctuations can be suppressed on the surface of the polarizing plate. Therefore, the polarizing plate obtained by the manufacturing method of the present invention can display a high quality image.

1‧‧‧ polarizing film

2, 3‧‧‧ transparent film

4‧‧‧Laminated body (polarizer)

11, 12‧‧‧ adhesive coating device

13‧‧‧Roller (cooling roller)

16, 17, 18, 31, 32‧‧‧Active energy line irradiation device

19‧‧‧Transport rolls

20‧‧‧Wind roller

51, 52‧‧‧ fitted roller

Fig. 1 is a schematic side view showing an embodiment of a manufacturing apparatus of a polarizing plate of the present invention.

The present invention relates to a method for producing a polarizing plate in which a transparent film is bonded to one surface or both surfaces of a polarizing film, and the method further comprises the step of applying an active energy ray-curable adhesive to one surface of the transparent film. a coating step of applying a pressure to the laminate of the transparent film and the polarizing film by applying a pressure to the laminate of the transparent film via the adhesive layer on one side or both sides of the polarizing film; The first active energy ray irradiation step of irradiating the laminate with the active energy ray and curing the adhesive between the laminate and the roller rotating in the transport direction is carried out. The maximum height Ry of the surface roughness of the roller used in the first active energy ray irradiation step is 0.4 to 12 s.

First, the respective requirements used in the manufacturing method of the present invention will be described in detail.

(polarized film)

The polarizing film used in the method for producing a polarizing plate of the present invention is specifically a method in which a univalently stretched polyvinyl alcohol-based resin film is used to adsorb a dichroic dye. The polyvinyl alcohol-based resin can be obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin, in addition to the polyvinyl acetate of a homopolymer of vinyl acetate, may be, for example, a copolymer of vinyl acetate and other monomers copolymerizable therewith (e.g., ethylene-acetic acid) Vinyl ester copolymer) and the like. Other monomers copolymerizable with vinyl acetate may, for example, be unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, ammonium-containing acrylamides, and the like. The degree of saponification of the polyvinyl alcohol-based resin is preferably 85 mol% or more, more preferably 90 mol% or more, and still more preferably 98 to 100 mol%. The average degree of polymerization of the polyvinyl alcohol-based resin is generally from 1,000 to 10,000, preferably from 1,500 to 5,000. These polyvinyl alcohol-based resins may be further denatured, for example, aldehyde-denatured polyethylene formaldehyde, polyvinyl acetaldehyde, polyvinyl butyral or the like may be used.

The film formed of the polyvinyl alcohol-based resin is used as an original film of a polarizing film. The method of forming a film from a polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventional method which is conventionally known. The film thickness of the embryonic film containing a polyvinyl alcohol-based resin is not particularly limited, and may be, for example, about 10 to 150 μm. Generally, this is supplied in a wheel shape, the thickness is in the range of 20 to 100 μm, preferably in the range of 30 to 80 μm, and the industrially practical width is in the range of 1500 to 6000 mm.

Commercially available polyvinyl alcohol film (Vinylon VF-PS #7500, manufactured by Kuraray Co., Ltd., Japan OPL film M-7500, manufactured by Nippon Synthetic Co., Ltd.) has a thickness of 75 μm (Vinylon VF-PS #6000, Japan Kuraray Co., Ltd.) The film thickness of the manufactured film, Vinylon VF-PE #6000, manufactured by Kuraray Co., Ltd., was 60 μm or the like.

The polarizing film is generally a polyvinyl alcohol-based resin film which is dyed with a dichroic dye to adsorb a dichroic dye (dyeing step), and a polyvinyl alcohol-based resin film which adsorbs a dichroic dye and then boric acid. The aqueous solution treatment step (boric acid treatment step) and the step of washing with the aqueous boric acid solution followed by water washing (water washing treatment step) are carried out.

Meanwhile, in the production of the polarizing film, generally, the polyvinyl alcohol-based resin film is uniaxially stretched, and the uniaxial stretching may be performed before the dyeing treatment step, or may be performed in the dyeing treatment step, or in the dyeing treatment. After the steps. When the uniaxial stretching is performed after the dyeing treatment step, the uniaxial stretching may be performed before the boric acid treatment step or in the boric acid treatment step. Of course, uniaxial extensions can also be made during these complex stages.

The uniaxial extension can be carried out in a uniaxial extension between the rollers having different rotational speeds, and can also be carried out by using a hot roller as a uniaxial extension. Further, it may be a dry stretching operation in which stretching is carried out in the atmosphere, or may be a wet stretching in which the film is swollen in a solvent. The magnification of the extension is generally about 3 to 8 times.

The polyvinyl alcohol-based resin film in the dyeing treatment step is dyed with a dichroic dye, and for example, the polyvinyl alcohol-based resin film can be immersed in an aqueous solution containing a dichroic dye. As the dichroic dye system, for example, iodine, a dichroic dye or the like can be used. The dichroic dye includes a dichroic direct dye composed of a disazo compound such as C.I.DIRECT RED 39, a dichroic direct dye composed of a compound such as triazole or tetrazole. Also, poly B The enol-based resin film is preferably subjected to water immersion treatment before the dyeing treatment.

When iodine is used as the dichroic dye, a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing iodine or potassium iodide and dyed is generally used. The iodine content in the aqueous solution is generally 0.01 to 1 part by weight per 100 parts by weight of water; the potassium iodide content is usually 0.5 to 20 parts by weight per 100 parts by weight of water. In the case of using iodine, the temperature of the aqueous solution used for dyeing is generally 20 to 40 ° C, and the immersion time (dyeing time) of such an aqueous solution is generally 20 to 1800 seconds.

On the other hand, when a dichroic dye is used as a dichroic dye, a method of dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye is generally used. The content of the dichroic dye in the aqueous solution is generally from 1 × 10 ^-4 to 10 parts by weight per 100 parts by weight of water, preferably from 1 × 10 ^-3 to 1 part by weight, particularly from 1 × 10 ^-3 It is more preferably 1 × 10 ^-2 parts by weight. The aqueous solution may further contain an inorganic salt such as sodium sulfate as a dyeing auxiliary. When a dichroic dye is used as the dichroic dye, the temperature of the dye aqueous solution used for dyeing is generally 20 to 80 ° C, and the immersion time (dyeing time) in the aqueous solution is usually 10 to 1800 seconds.

The boric acid treatment step is carried out by immersing the polyvinyl alcohol-based resin film dyed with the dichroic dye in an aqueous solution containing boric acid. The amount of boric acid in the aqueous solution containing boric acid is usually 2 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. When iodine is used as the dichroic dye in the dyeing step, the aqueous solution containing boric acid used in the boric acid treatment step is preferably potassium iodide. At this time, the amount of potassium iodide in the aqueous solution containing boric acid is usually 0.1 to 15 parts by weight per 100 parts by weight of water, preferably 5 to 12 parts by weight. The immersion time in the aqueous solution containing boric acid is generally 60 to 1200 seconds, preferably 150 to 600 seconds, and 200. Better to 400 seconds. The temperature of the aqueous solution containing boric acid is generally 40 ° C or higher, preferably 50 to 85 ° C, more preferably 55 to 75 ° C.

Next, in the water washing treatment step, the above-described boric acid-treated polyvinyl alcohol-based resin film is subjected to a water washing treatment by immersion in water. The temperature of the water in the water washing treatment is generally 4 to 40 ° C, and the immersion time is usually 1 to 120 seconds. After the water washing treatment, the drying treatment is generally carried out to obtain a polarizing film. The drying treatment can be suitably carried out using, for example, a hot air dryer, a far infrared heater, or the like. The drying treatment temperature is usually from 30 to 100 ° C, preferably from 50 to 80 ° C. The drying treatment time is generally 60 to 600 seconds, preferably 120 to 600 seconds.

The polyvinyl alcohol-based resin film thus obtained is subjected to uniaxial stretching, dichroic dyeing, boric acid treatment, and water washing treatment to obtain a polarizing film. The thickness of the polarizing film is generally in the range of 5 to 50 μm.

(Transparent film)

In the present invention, the one or both surfaces of the polarizing film are bonded together by a transparent film. The constituent material of the transparent film may, for example, be a cycloolefin resin, a cellulose acetate resin, or a polyester such as polyethylene terephthalate or polyethylene naphthalate or polybutylene terephthalate. A resin material, a polycarbonate resin, an acrylic resin, polypropylene, or the like, a film material widely used in the field. When the polarizing film is bonded to each other with a transparent film, the respective transparent films may be the same or different types of films.

An example of the cycloolefin resin is a thermoplastic resin (also referred to as a thermoplastic cycloolefin resin) having a monomer unit of a cyclic olefin (cycloolefin) such as norbornene or a polycyclic ortho-ene monomer. The cycloolefin resin may be a ring-opening polymer of the above cycloolefin or a hydrogenated product of a ring-opening copolymer of two or more kinds of cyclic olefins, an addition of a cyclic olefin, a chain olefin, an aromatic compound having a vinyl group, or the like. polymer. In addition, the import has Polar bases are also effective.

When a copolymer of a cyclic olefin and a chain olefin and/or an aromatic compound having a vinyl group is used, examples of the chain olefin include ethylene, propylene, etc.; and examples of the aromatic compound having a vinyl group include : styrene, α-methylstyrene, nucleoalkyl-substituted styrene, and the like. In such a copolymer, the monomer unit containing a cyclic olefin may be 50 mol% or less (preferably 15 to 50 mol%). In particular, when a terpolymer of a cyclic olefin and a chain olefin and an aromatic compound having a vinyl group is used, the monomer unit containing a cycloolefin may be in an amount as small as described above. The terpolymer of the terpolymer includes a monomer unit of a chain olefin, generally 5 to 80 mol%, and a monomer unit containing an aromatic compound having a vinyl group, and is usually 5 to 80 mol%.

For the cycloolefin resin, a commercially available product such as Topas (manufactured by Ticona Co., Ltd.), ARTON (manufactured by JSR Corporation), ZEONOR (manufactured by Zeon Corporation of Japan), ZEONEX (manufactured by Zeon Corporation of Japan), and APEL (Mitsui Chemical Co., Ltd.) can be used. Manufactured by OXIS (manufactured by Okura Industrial Co., Ltd.). When a film is formed from such a cycloolefin resin, a conventionally known method such as a solvent casting method or a melt extrusion method is suitable for use. In addition, a commercially available film of a cycloolefin-based resin such as S-SINA (manufactured by Sekisui Chemical Co., Ltd.), SCA 40 (manufactured by Sekisui Chemical Co., Ltd.), or ZEONOR Film (manufactured by Zeon Co., Ltd.) may be used. Product.

The cycloolefin resin film may be uniaxially stretched or biaxially stretched. By extending, any phase difference value of the cycloolefin resin can be imparted. The extension, in general, is carried out continuously while the film roll is being wound out, and can be carried out in the direction of the roll (the length direction of the film), the direction perpendicular to the direction (the width direction of the film), or Its two sides extend. The temperature of the heating furnace is generally in the range from the vicinity of the glass transition temperature of the cycloolefin resin to the glass transition temperature + 100 °C. The stretching ratio is generally 1.1 to 6 times, preferably 1.1 to 3.5 times.

In the cycloolefin-based resin film, when the roller is wound, the film tends to be agglomerated after being adhered to the film. Therefore, generally, the film is bonded after the film is bonded. Further, since the cycloolefin-based resin film generally has a poor surface activity, it is preferred that the surface of the polarizing film is subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, saponification treatment or the like. . Among them, the plasma treatment which is easier to implement, especially the plasma treatment and corona treatment under atmospheric pressure, is suitable.

The cellulose acetate-based resin is a partial or complete esterified product of cellulose, and examples thereof include a film comprising cellulose acetate, propionate, butyrate, or a mixed ester thereof. More specifically, a triethylene fluorene cellulose film, a diethyl fluorene cellulose film, a cellulose acetate propionate film, a cellulose acetate butyrate film, etc. are mentioned. For the cellulose ester-based resin film, a commercially available product such as FUJITAC TD80 (manufactured by Fujifilm Co., Ltd.), FUJITAC TD80UF (manufactured by Fujifilm Co., Ltd.), FUJITAC TD80UZ (manufactured by Fujifilm Co., Ltd.), KC8UX2M (Konica-) can be used. Manufactured by Minolta Opto Co., Ltd., KC8UY (manufactured by Konica-Minolta Opto Co., Ltd.), FUJITACTD 60UL (manufactured by Fujifilm Co., Ltd.), KC2UAW (manufactured by Konica-Minolta Opto Co., Ltd.), KC4UYW (manufactured by Konica-Minolta Opto Co., Ltd.), KC6UAW (Konica-Minolta Opto) Company manufacturing) and so on.

Meanwhile, in terms of a transparent film, a cellulose acetate resin film having a phase difference characteristic is also suitable for use. Commercial products of the cellulose acetate-based resin film having a phase difference characteristic include WV BZ 438 (manufactured by Fujifilm Co., Ltd.), KC4FR-1 (manufactured by Konica-Minolta Opto Co., Ltd.), and KC4CR-1 (Konica- Manufactured by Minolta Opto Co., Ltd., KC4AR-1 (manufactured by Konica-Minolta Opto Co., Ltd.), and the like. Cellulose acetate, also known as acetyl cellulose, is also known as cellulose acetate.

Such a cellulose acetate-based resin film is easy to absorb water, and therefore the moisture content of the polarizing plate affects the relaxation of the end of the polarizing plate. Therefore, the moisture content at the time of manufacture of the polarizing plate is preferably as close as possible to the storage environment of the polarizing plate, such as the clean room manufacturing line and the winding storage warehouse, although the composition of the laminated film is determined, For example, it is preferably about 2.0 to 3.5%, more preferably about 2.5% to 3.0%. The numerical value of the moisture content of the polarizing plate was measured by the dry weight method, that is, its weight change after 105 ° C / 120 minutes.

The thickness of the transparent film used in the method for producing a polarizing plate of the present invention is preferably thin, but when it is too thin, the strength is lowered and the workability is deteriorated. On the other hand, when it is too thick, there is a problem that the transparency is lowered or the curing time necessary after lamination is prolonged. Therefore, the transparent film is known to have a suitable thickness, for example, 5 to 200 μm, preferably 10 to 150 μm, more preferably 10 to 100 μm.

In order to improve the adhesion between the adhesive and the polarizing film and/or the transparent film, corona treatment, flame treatment, plasma treatment, ultraviolet irradiation treatment, and undercoat coating may be applied to the polarizing film and/or the transparent film. Surface treatment such as treatment, saponification treatment.

At the same time, the transparent film may be subjected to surface treatment such as anti-glare treatment, anti-reflection treatment, cured film treatment, antistatic treatment, antifouling treatment, or the like, either alone or in combination of two or more. Meanwhile, the transparent film and/or the transparent film surface protective layer may further contain a UV absorber such as a benzophenone compound or a benzotriazole compound; and a phenyl phosphate compound or a phthalate compound. Plasticizer.

Others, the transparent film may also have: the function of the retardation film, the function of the brightness enhancement film, the function of the reflection film, the function of the semi-transmissive reflection film, the function of the diffusion film, the function of the optical compensation film, etc., optical function . At this time, for example, on the surface of the transparent film, a retardation film, a brightness enhancement film, a reflection film, a semi-transmissive reflection film, a diffusion film, An optical functional film layer such as an optical compensation film, in addition to such a function, imparts such a function to the transparent film itself. Further, the transparent film may have a plurality of functions such as a diffusion film having a function of improving the brightness of the film.

For example, the above-mentioned transparent film can be carried out by applying the stretching treatment as described in Japanese Patent No. 2841377, Japanese Patent No. 3094113, or the processing described in Japanese Patent No. 3168850. Gives the function of the retardation film. The phase difference characteristic in the retardation film can be appropriately selected, for example, in the range of the front retardation value of 5 to 100 nm, the thickness direction retardation value of 40 to 300 nm, and the like. At the same time, fine pores may be formed on the above-mentioned transparent film by the method described in JP-A-2002-169025 and JP-A-2003-29030, or two layers having different center wavelengths of selective reflection. When the above cholesteric liquid crystal layers are overlapped, the function of the brightness enhancement film can be imparted.

When a metal thin film is formed by vapor deposition or sputtering on the above transparent film, the function of the reflective film or the semi-transmissive reflective film can be imparted. When the above transparent film is coated with a resin solution containing fine particles, the function of the diffusion film can be imparted. At the same time, when the above-mentioned transparent film is further coated with a liquid crystalline compound such as a discotic liquid crystalline compound, the optical compensation film function can be imparted. Further, the transparent film may also contain a compound which exhibits a phase difference. Further, various optical functional films may be directly bonded to the polarizing film with a suitable adhesive. The commercially available product of the optical functional film may be a brightness-enhancing film such as DBEF (manufactured by Sumitomo 3M Co., Ltd., manufactured by 3M Company, Japan), or a WN film (manufactured by Fujifilm Co., Ltd.). Phases manufactured by Japan JSR Co., Ltd., ZEONOR film (manufactured by Optes), S-SINA (manufactured by Japan Sekisui Chemical Co., Ltd.), VA-TAC (manufactured by Konica-Minolta Opto, Japan), and Sumikalite (manufactured by Sumitomo Chemical Co., Ltd.) Bad film, etc.

(active energy ray hardening type adhesive)

The polarizing film and the transparent film may be bonded via an active energy ray-curable adhesive. The active energy ray-curable adhesive is composed of an epoxy resin composition containing an epoxy resin which is cured by irradiation with an active energy ray, from the viewpoints of weather resistance, refractive index, and cationic polymerizability. The adhesive. However, the present invention is not limited thereto, and various active energy ray-curable adhesives (organic solvent-based adhesives, hot-melt adhesives, solvent-free adhesives, etc.) which have been conventionally used for the production of polarizing plates can be used. For example, an adhesive composed of an acrylic resin composition such as acrylamide, acrylate, urethane acrylate or acrylate acrylate can be used.

Epoxy resin means a compound having two or more epoxy groups in its molecule. From the viewpoints of weather resistance, refractive index, cationic polymerizability, and the like, the epoxy resin contained in the curable epoxy resin composition of the adhesive is an epoxy resin containing no aromatic ring in the molecule (refer to, for example, the patent document) 1) is better. Examples of such epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins.

Hydrogenated epoxy resin, which can be obtained by epoxy propyl etherification of a polyhydroxy compound obtained from a polynuclear compound of an aromatic epoxy resin in the presence of a catalyst by selective nuclear hydrogenation under pressure You can get it. Examples of the aromatic epoxy resin include a bisphenol ring of bisphenol A, a diglycidyl ether of bisphenol F, and a diphenolic propyl ether of bisphenol S. Oxygen resin; phenolic novolac epoxy resin, cresol novolac epoxy resin, and phenolic phenolic novolac epoxy resin and other novolac type epoxy resin; tetrahydroxyphenylmethane epoxypropyl A polyfunctional epoxy resin such as an ether, a glycidyl ether of tetrahydroxybenzophenone, or an epoxidized polyvinyl phenol. Among the hydrogenated epoxy resins, a hydrogenated bisphenol A epoxypropyl ether is preferred.

An alicyclic epoxy resin means that one or more bonds are bonded to the alicyclic ring in the molecule. The epoxy resin is intended to be epoxy. The "epoxy group bonded to the alicyclic ring" means the crosslinked oxygen atom -O- in the structure shown by the following formula. In the following formula, m is an integer of 2 to 5.

An alicyclic epoxy resin can be obtained by bonding a compound having a form in which one or more hydrogen atoms in (CH ₂ ) _m in the above formula are bonded to another chemical structure. One or more hydrogen atoms of (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. Among the alicyclic epoxy resins, an epoxy resin having an oxybicyclohexane ring (which is m=3 in the above formula) and an oxybicycloheptane ring (which is m=4 in the above formula) may be used. It shows excellent adhesion and is therefore better to use. Hereinafter, specific examples of the more preferable alicyclic epoxy resin are used, but the compounds are not limited thereto.

(a) Epoxycyclohexanecarboxylic acid epoxycyclohexylmethyl ester represented by the following formula (I): (wherein R ¹ and R ² are independently of each other and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)

(b) an epoxycyclohexane carboxylate of an alkanediol represented by the following formula (II): (wherein R ³ and R ⁴ are independently of each other, and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and n represents an integer of 2 to 20.)

(c) Epoxycyclohexylmethyl esters of dicarboxylic acids represented by the following formula (III): (wherein R ⁵ and R ⁶ are independently of each other and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and p represents an integer of 2 to 20.)

(d) Epoxy cyclohexyl methyl ether of polyethylene glycol represented by the following formula (IV): (wherein R ⁷ and R ⁸ are independently of each other and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and q represents an integer of 2 to 10.)

(e) an epoxycyclohexyl methyl ether of an alkanediol represented by the following formula (V): (wherein R ⁹ and R ¹⁰ are independently of each other and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and r represents an integer of 2 to 20.)

(f) a diepoxide trispirate compound represented by the following formula (VI): (wherein R ¹¹ and R ¹² are independently of each other and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)

(g) a diepoxy single spiro compound represented by the following formula (VII): (wherein R ¹³ and R ¹⁴ are independently of each other and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)

(h) Diethylene vinylcyclohexenes of the following formula (VIII): (wherein R ¹⁵ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)

(i) Epoxycyclopentyl ethers of the following formula (IX): (wherein R ¹⁶ and R ¹⁷ are independently of each other and represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)

(j) Diepylene tricyclodecanes of the following formula (X): (wherein R ¹⁸ represents a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms.)

Among the alicyclic epoxy resins exemplified above, the following alicyclic epoxy resins are more preferably used because they are commercially available or are analogously easy to obtain.

(A) an ester of 7-oxabicyclo[4.1.0]heptane-3-carboxylic acid with (7-oxabicyclo[4.1.0]heptan-3-yl)methanol [in formula (I) a compound of R ¹ =R ² =H], (B) 4-methyl-7-oxabicyclo[4.1.0]heptane-3-carboxylic acid and (4-methyl-7-oxadiyl) Ester of ring [4.1.0]heptan-3-yl)methanol [in the formula (I), R ¹ =4-CH ₃ , R ² =4-CH ₃ compound], (C) 7-oxa di An ester of cyclo[4.1.0]heptane-3-carboxylic acid with 1,2-ethanediol [in the formula (II), a compound of R ³ =R ⁴ =H, n=2], (D) An ester of (7-oxabicyclo[4.1.0]heptan-3-yl)methanol with adipic acid [in the formula (III), a compound of R ⁵ =R ⁶ =H, p=4], (E An ester of (4-methyl-7-oxabicyclo[4.1.0]heptan-3-yl)methanol with adipic acid [in formula (III), R ⁵ =4-CH ₃ , R ⁶ = a compound of 4-CH ₃ , p=4], (F) (7-oxabicyclo[4.1.0]heptan-3-yl)methanol and 1,2-ethanediol [Formula (V) In the formula, R ⁹ = R ¹⁰ = H, compound of r = 2].

Further, the aliphatic epoxy resin may, for example, be a polyglycidyl ether of an aliphatic polyol or an alkylene oxide adduct thereof. More specifically, it may, for example, be a diglycidyl ether of 1,4-butanediol; a diglycidyl ether of 1,6-hexanediol; a triglycidyl ether of glycerol; a triglycidyl ether of methylolpropane; a diglycidyl ether of polyethylene glycol; a diglycidyl ether of propylene glycol; Polyglycidyl ether of a polyether polyol obtained by adding an aliphatic polyol such as ethylene glycol, propylene glycol or glycerin to one or more kinds of alkylene oxides (ethylene oxide and propylene oxide) Wait.

The epoxy resin which comprises an adhesive agent which consists of an epoxy resin composition can be used individually, and can also use together 2 or more types. The epoxy group equivalent of the epoxy resin used in the composition is usually from 30 to 3,000 g/equivalent, preferably from 50 to 1,500 g/equivalent. When the epoxy equivalent is less than 30 g/equivalent, the flexibility of the composite polarizing plate after hardening is lowered, or the strength is subsequently lowered. On the other hand, when it exceeds 3,000 g/eq, the miscibility with other components contained in the adhesive may be lowered.

Among the above-mentioned adhesives, from the viewpoint of reactivity, cationic curing is applied as a curing reaction of an epoxy resin. Therefore, in the curable epoxy resin composition of the active energy ray-curable adhesive, it is preferred to formulate a cationic polymerization initiator. The cationic polymerization initiator is a cationic species or a Lewis acid which is irradiated with an active energy ray such as visible light, ultraviolet light, X-ray or electron beam to initiate polymerization of an epoxy group. Hereinafter, a cationic polymerization initiator which generates a cationic species or a Lewis acid by irradiation with an active energy ray and starts the polymerization of an epoxy group is referred to as a "photocationic polymerization initiator".

The photocationic polymerization initiator is used to harden the adhesive by irradiation with an active energy ray, and can be hardened at normal temperature, so that the heat resistance of the polarizing film or the reduction of the skew due to expansion can be considered, and the film can be interposed between the films. It is also beneficial to have a good point to follow. At the same time, the photocationic polymerization initiator acts on light as a catalyst, so that it can be preserved in an epoxy resin for better storage stability and workability.

The photocationic polymerization initiator may, for example, be an aromatic diazonium salt; an onium salt such as an aromatic onium salt or an aromatic onium salt; an iron-aromatic hydrocarbon complex or the like.

Examples of the aromatic diazonium salt include benzene diazonium hexafluoroantimonate, benzodiazepine hexafluorophosphate, and benzodiazepine hexafluoroborate. Meanwhile, examples of the aromatic sulfonium salt include diphenyl sulfonium tetrakis(pentafluorophenyl)borate, diphenyl hydrazine hexafluorophosphate, diphenyl hydrazine hexafluoroantimonate, and bis(4-fluorenylphenyl hexafluorophosphate). )錪.

Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, and 4,4'-di of bis(hexafluorophosphate). (diphenyldihydrothio) diphenyl sulfide, bis(hexafluoroantimonate) 4,4'-bis[bis(β-hydroxyethoxy)phenyldihydrothio]diphenyl sulfide, di(six) Fluorophosphoric acid) 4,4'-bis[bis(β-hydroxyethoxy)phenyldihydrothio]diphenyl sulfide, hexafluoroantimonic acid 7-[bis(p-tolylmethyl)dihydrothio] 2-isopropyl thioxanthone, tetrakis(pentafluorophenyl)borate 7-[bis(p-tolylmethyl)dihydrothio]-2-isopropylthioxanthone, six 4-phenylcarbonyl-4'-diphenyldihydrothio-diphenyl thiophosphate, hexafluoroantimonate-4-(p-tert-butylphenylcarbonyl)-4'-diphenyldihydrothio-diphenyl Sulfur, tetrakis(pentafluorophenyl)borate 4-(p-tert-butylphenylcarbonyl)-4'-di(p-tolylmethyl)dihydrothio-diphenyl sulfide, and the like.

Examples of the iron-aromatic complex are hexafluoroantimony xylene-cyclopentadiene ferrous (II), cumene hexafluoro-cyclopentadiene ferrous (II), xylene- Cyclopentadiene ferrous (II)-tris(trifluoromethyl sulfonium) methanide and the like.

A commercially available product of such a photocationic polymerization initiator can be easily obtained, for example, "KAYARAD PCI-220" and "KAYARAD PCI-620" (all of which are manufactured by Nippon Kayaku Co., Ltd.), "UVI". -6990" (manufactured by Union-Carbide), "Adekaoptomer SP-150" and "Adekaoptomer SP-170" (all of which are manufactured by ADEKA, Japan), "CI-5102", "CIT-1370", "CIT-1682" "CIP-1866S", "CIP-2048S" and "CIP-2064S" (all of which are manufactured by Japan's Soda Corporation), "DPI-101", "DPI-102", "DPI-103", "DPI-" 105", MPI-103, MPI-105, BBI-101, BBI-102, BBI-103, BBI-105, TPS-101, TPS-102, TPS -103", "TPS-105", "MDS-103", "MDS-105", "DTS-102" and "DTS-103" (all of which are manufactured by Nippon Green Chemical Co., Ltd.) and "PI-2074" ( Rhodia company) and so on.

The photocationic polymerization initiator may be used singly or in combination of two or more kinds. Among them, the aromatic cerium salt has ultraviolet absorbing properties even in the wavelength region of 300 nm or more, and thus is excellent in curability and has a good mechanical strength and a bonding strength.

The compounding amount of the photocationic polymerization initiator is usually 0.5 to 20 parts by weight, more preferably 1 part by weight or more, and still more preferably 15 parts by weight or less based on 100 parts by weight of the epoxy resin. When the amount of the photocationic polymerization initiator is less than 0.5 part by weight based on 100 parts by weight of the epoxy resin, the curing is incomplete, and the mechanical strength and the subsequent strength tend to be lowered. At the same time, when the amount of the photocationic polymerization initiator is more than 20 parts by weight based on 100 parts by weight of the epoxy resin, the ionic substance in the cured product is increased to improve the hygroscopicity of the cured product, and the durability can be lowered. The situation.

When a photocationic polymerization initiator is used, the curable epoxy resin composition may further contain a photosensitizer as necessary. When a photosensitizer is used, the reactivity of the cationic polymerization can be increased to increase the mechanical strength and the subsequent strength of the cured product. Examples of the photosensitizer include a carbonyl compound, an organic sulfur compound, a persulfide compound, a redox compound, an azo and a diazo compound, a halogen compound, and a photoreductive dye.

More specific examples of the photosensitizer include benzoin methyl ether, benzoin isopropyl ether, and benzoin derivatives such as α,α-dimethoxy-α-phenylethyl benzene; Benzophenone, 2,4-dichlorobenzophenone, methyl phthalic acid benzoate, 4,4'-di(dimethylamino)benzophenone, and 4,4'-di (two Benzophenone derivatives such as ethylamine)benzophenone; 2- a thioxanthone derivative such as chlorthiazinone or 2-isopropylthioxanthone; an anthracene derivative such as 2-chloroindole and 2-methylindole; N-methylacridone And acridine derivatives such as N-butylacridone; others, α,α-diethoxyethylbenzene, diphenylethylenedione, anthrone, xanthones, uranium compounds, halogens Compounds, etc. The photosensitizer may be used alone or in combination of two or more. The photosensitizer is preferably contained in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the curable epoxy resin composition.

The epoxy resin contained in the subsequent agent may be photo-cationically polymerized to be cured, or may be cured by both photocationic polymerization and thermal cationic polymerization. In the latter case, a combination of a photocationic polymerization initiator and a thermal cationic polymerization initiator is preferred.

Examples of the thermal cationic polymerization initiator include benzyl phosphonium salt, thiophene salt, tetrahydrothiophene salt, benzylammonium salt, pyridinium salt, phosphonium salt, carboxylate, sulfonate, and amine sulfonate. Amines, etc. These thermal cationic polymerization initiators are commercially available, and are commercially available as "Adekaopton CP77" and "Adekaopton CP66" (all of which are manufactured by ADEKA), "CI-2639" and " CI-2624" (all of which are manufactured by Japan's Soda Corporation), "San-Aid SI-60L", "San-Aid SI-80L" and "San-Aid SI-100L" (all of which are Japan Sanxin Chemical Industry Co., Ltd.) Manufacturing) and so on.

The active energy ray-curable adhesive may further contain a compound which promotes cationic polymerization such as oxygen cyclobutanes and polyhydric alcohols.

Oxycyclobutanes are compounds having a 4-membered cyclic ether in the molecule, and may, for example, be 3-ethyl-3-hydroxymethyloxycyclobutane or 1,4-bis[(3-ethyl-3) -oxocyclobutyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxycyclobutane, bis[(3-ethyl-3-oxocyclobutane)methyl] Ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxycyclobutane, phenol novolac oxocyclobutane, and the like. These oxocyclobutanes can be easily obtained from commercially available products, for example, "ARON OXETANE OXT-101" and "ARON OXETANE OXT-121". "ARON OXETANE OXT-211", "ARON OXETANE OXT-221" and "ARON OXETANE OXT-212" (all of which are manufactured by East Asia Synthetic Co., Ltd.). These oxycyclobutanes are generally contained in the curable epoxy resin composition in a proportion of 5 to 95% by weight, preferably 30 to 70% by weight.

The polyol is preferably an acid group other than the phenolic hydroxyl group, and examples thereof include a polyol compound having no functional group other than a hydroxyl group, a polyester polyol compound, and a polycaprolactone polyol compound. A polyol compound of a phenolic hydroxyl group, a polycarbonate polyol, or the like. The molecular weight of these polyols is generally 48 or more, preferably 62 or more, more preferably 100 or more, and still more preferably 1,000 or less. The polyhydric alcohols are generally contained in a curable epoxy resin composition in an amount of 50% by weight or less, preferably 30% by weight or less.

The active energy ray-curable adhesive can be further formulated: an ion trapping agent, an antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a leveling agent, a plasticizer, Additives such as defoamers. Examples of the ion trapping agent include inorganic compounds such as powdery lanthanum, lanthanide, magnesium, aluminum, calcium, titanium, and the like; examples of the antioxidant include hindered phenolic compounds. Antioxidants, etc.

The active energy ray-curable adhesive can be used as a solventless adhesive which does not contain a solvent component in essence, but each coating processing method also has an optimum viscosity range, and therefore may contain a solvent for adjusting the viscosity. In terms of the solvent, it is preferable that the epoxy resin composition is not dissolved, and the epoxy resin composition can be dissolved, for example, a hydrocarbon represented by toluene or an ester represented by ethyl acetate. Solvent. The viscosity of the active energy ray-curing type adhesive used in the present invention may be, for example, in the range of about 5 to 1000 mPa ‧ s, preferably 10 to 200 mPa ‧ , and 20 to 100mPa‧s is better.

<Method of Manufacturing Polarizing Plate>

Next, a manufacturing apparatus and a manufacturing method of the polarizing plate of the present invention will be described with reference to the drawings. Fig. 1 is a schematic view showing an embodiment of a manufacturing apparatus used in the method for producing a polarizing plate of the present invention.

The apparatus for manufacturing a polarizing plate shown in Fig. 1 is provided in the order of the transport direction, in which the adhesive coating apparatuses 11, 12 for applying an adhesive on one surface of the transparent films 2, 3, and The transparent films 2, 3 and the polarizing film 1 are bonded together to obtain a bonding roller (roller) 51, 52 for the laminated body 4, a roller 13 for adhering the laminated body 4, and a peripheral surface of the roller 13 The first active energy ray irradiation devices 31 and 32 provided at the positions, the second active energy ray irradiation devices 16 to 18 provided on the downstream side in the transport direction, and the transport roller 19 are provided.

First, an active energy ray-curable adhesive is applied to one surface of the transparent films 2 and 3 which are continuously fed in a state of being wound into a wheel shape (the adhesive application step) by the adhesive application devices 11 and 12.

Then, on both surfaces of the polarizing film 1 which are continuously fed in a state of being wound into a wheel shape, the laminated body coated with the adhesive-coated transparent films 2 and 3 via an adhesive agent is rotated in one direction in the transport direction. In a state in which the bonding rollers 51 and 52 are press-fitted, at least one of the bonding rollers is pressed in the direction of the other bonding roller, and pressure is applied to the laminated body to cause the polarizing film 1 and the transparent film 2 And 3 are bonded together to form a laminated body 4 (a bonding step).

Then, in the process of transporting the laminated body 4 while the outer peripheral surface of the roller 13 is in close contact with each other, the first active energy ray irradiation devices 31 and 32 irradiate the outer peripheral surface of the roller 13 with an active energy ray to cure the adhesive. (1st active energy ray irradiation step Step).

In addition, the second active energy ray irradiation devices 16 to 18 disposed on the downstream side in the transport direction are devices for completely curing and curing the second adhesive (second active energy ray irradiation step), and may be added or omitted as necessary. However, since the second active energy ray irradiation step can completely cure and cure the adhesive, in the first active energy ray irradiation step, the adhesive does not necessarily have to be completely polymerized and hardened, so that the wave can be generated. Since it is suppressed and it is easy to control the amount of light accumulated by the active energy ray, it is preferable to have the second active energy ray irradiation step. Finally, the laminated body 4 is passed through the conveying roller 19, and the polarizing plate is wound by the winding roller 20. Hereinafter, each step will be described in detail.

(adhesive coating step)

The coating method of the transparent agent in the transparent films 2 and 3 is not particularly limited, and various coating methods such as a doctor blade, a wire bar, a die-casting mold, a comma, and a gravure roll can be used. Among them, in consideration of the degree of freedom in film coating, transporting the moving line, and the wideness, the adhesive coating devices 11 and 12 are preferably gravure rolls.

When the gravure roll is used as the adhesive applicator 11 and 12 for the adhesive application, the thickness (coating thickness) of the applied adhesive is preferably from about 0.1 to 10 μm, more preferably from 0.2 μm to 4 μm. The coating thickness of the subsequent agent can be adjusted by the draw ratio of the speed of the gravure roll relative to the moving speed of the transparent film. In general, when the draw ratio (speed of the gravure roll/moving speed) is adjusted to 0.5 to 10, the coating thickness of the adhesive can be adjusted to about 0.1 to 10 μm. More specifically, the moving speed of the transparent films 2, 3 is set to 10 to 100 m/min, and the conveying direction of the gravure roll and the transparent films 2, 3 is reversed, and the speed of the gravure roll is set to 5 to 1000 m. The coating thickness of the adhesive can be adjusted to about 0.1 to 10 μm at /min.

The subsequent agent is preferably at a predetermined temperature of ±5 ° C in the range of 15 to 40 ° C (for example, 30 ° C ± 5 ° C at a predetermined temperature of 30 ° C), preferably ± 3 ° C. Coating is carried out in an environment that is better adjusted to ±1 °C.

(Fitting step)

In this step, the transparent films 2 and 3 coated with the adhesive in the above-described steps are laminated on the both surfaces of the polarizing film 1 which are continuously fed in a state of being wound up. The laminated body is pressed in the direction in which the pair of bonding rollers 51 and 52 are pressed in the transport direction, for example, by the bonding roller 51 in the direction of the bonding roller 52, so that the polarizing film 1 and the transparent film 2 are pressed. And 3 are bonded together to form the laminated body 4. At this time, the angle perpendicular to the direction in which the pressing roller is pressed is set to an angle within a range of ±3°, more preferably within an angle of ±1°, particularly overlapping the surface perpendicular to the extrusion direction. It is preferred that the polarizing film is transported between the bonding rollers. Under this operation, the polarizing film and the transparent film can be brought into contact with the front end of the bonding roller without bubble generation.

As shown in Fig. 1, the one surface of the transparent films 2 and 3 is uniformly coated with an adhesive, and the surface of the transparent films 2 and 3 coated with the adhesive is superposed on the polarizing film 1 and passed through the bonding rollers 51 and 52. The method of fitting.

As the material of the bonding rollers 51 and 52, for example, a metal roller and a rubber roller can be exemplified. It is preferable that one of the pair of bonding rollers 51 and 52 is a metal roller and the other is a rubber roller. The base material of the metal roller can be made of various known materials, and SUS304 is preferred, and the surface is preferably chrome-plated. Further, the material of the rubber roller is not particularly limited, and examples thereof include EPDM, NBR, polyurethane, titanium, and barium. The hardness of the rubber roller is not particularly limited and is generally 60 to 100°, preferably 85 to 95°. Moreover, the hardness of the rubber roller can be measured according to the hardness meter of JIS K 6253. A commercially available hardness tester, such as a rubber hardness tester manufactured by Japan Aska Co., Ltd. "Type-A" and so on. Specifically, when the surface is pressed by a rod, the resistance to the surface of the rubber roller is measured by a hardness meter.

The contact pressure of the metal roller and the rubber roller is preferably 0.5 to 3.0 MPa at a pressure of 0.5 to 3.0 MPa in a two-sheet type press case (for ultra low pressure) manufactured by Fujifilm Japan. 2.3MPa is better. The diameter of the bonding rollers 51 and 52 is not particularly limited and is generally 50 to 400 nm. Further, the diameters of the two (one pair) bonding rollers 51 and 52 may be the same or different.

(first active energy ray irradiation step)

The roller 13 has an outer peripheral surface formed by a convex curved surface having a predetermined surface roughness, and its surface is transported while the laminated body 4 is in close contact, and the adhesive is irradiated by the active energy ray irradiation means 31, 32 in the process. hardening. When the adhesive is polymerized and hardened, and the laminated body 4 is sufficiently adhered, the diameter of the roller 13 is not particularly limited. The roller 13 is rotated by the rotational speed of the linear velocity, and when the rotational speed of the rubber roller is 100, it is preferably 100.1 or more and 102.0 or less. At the same time, when the roller 13 is polymerized and cured by irradiation with an active energy ray, it can also function as a cooling roller for dissipating heat generated by the laminated body 4. At this time, it is preferable to set the surface temperature of the cooling roller to 4 to 30 °C.

The outer peripheral surface of the roller 13 has a maximum surface roughness Ry of preferably 0.4 to 12 s, more preferably 0.8 to 6.0 s. The outer peripheral surface of the roller 13 may also be sandblasted and ground to form a predetermined roughness. When the maximum height Ry of the surface roughness is less than 0.4 S, a wave-like undulation of waves such as waves may occur on the surface of the polarizing plate. On the other hand, when the maximum height Ry of the surface roughness exceeds 12 seconds, the uneven shape of the outer peripheral surface of the roller 13 may be transferred to the surface of the polarizing plate. Further, the maximum height Ry of the surface roughness in the present invention is a value specified in JIS B0601-1994.

The light source used for the polymerization hardening of the adhesive agent by irradiation with an active energy ray is not particularly limited, but a light source having a light-emitting distribution at a wavelength of 400 nm or less is preferable. Examples of such a light source include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excited mercury lamp, and a metal halogen. light. The irradiation of the active energy ray in the first active energy ray irradiation step is preferably carried out in multiple steps. In the first drawing, the irradiation of the active energy ray is performed twice, that is, when two light sources (the active energy ray irradiation devices 31 and 32) are arranged along the transport direction of the laminated body, but it is not limited to two times. If it is divided into 3 times, it can be done.

The intensity of light irradiation of each of the active energy ray-curable adhesives is determined by the respective compositions of the adhesive, and is not particularly limited, but is preferably 10 to 5000 mW/cm ² . When the light irradiation intensity of the resin composition is less than 10 mW/cm ² , the reaction time will be too long. When it exceeds 5000 mW/cm ² , the heat radiated from the light source and the heat generated during the polymerization of the composition may have an adhesive. The yellowing of the epoxy resin composition of the constituent material, and the occurrence of aging of the polarizing film. Further, the irradiation intensity is preferably in the wavelength range effective for activation of the photocationic polymerization initiator, and is preferably in the wavelength range of 400 nm or less, and in the wavelength range of 280 to 320 nm. The strength is even better.

When the active energy ray is ultraviolet ray, the laminated body 4 is applied to the longitudinal direction (transport direction) at a tension of 100 to 800 N/m in the active energy ray irradiation step, and the irradiation time is 0.1 second or longer. It is preferable to transport the laminated body 4 at the linear velocity.

(second active energy ray irradiation step)

When the amount of accumulated light energy of the active energy ray of the active energy ray irradiation devices 31 and 32 is insufficient, the second or lower active energy ray irradiation devices 16 to 18 are further provided, and the active energy ray is additionally irradiated to promote the adhesive of the laminated body 4. Hardened is better. The cumulative amount of light in the entire step of the first active energy ray irradiation step is preferably 10 mJ/cm ² or more, and preferably 10 to 5,000 mJ/cm ² . When the cumulative amount of the above-mentioned adhesive is less than 10 mJ/cm ² , the occurrence of the active species derived from the initiator is insufficient, and the curing of the adhesive is insufficient. On the other hand, when the accumulated light amount exceeds 5,000 mJ/cm ² , the irradiation time becomes too long, which is unfavorable for improvement in productivity. In this case, depending on the type of film to be used and the type of the adhesive, etc., in which wavelength range (UVA (320 to 390 nm), UVB (280 to 320 nm), etc.), the amount of accumulated light is not necessarily the same.

In order to ensure the hardening of the adhesive at the end of the polarizing plate (layered body), for example, a method in which the "Light Hammer 10" manufactured by FUSION Co., Ltd. of Japan, which is an electrodeless D bulb, is arranged transversely with respect to the film is exemplified.

The ratio of the active energy ray-curable resin hardening, that is, the reaction rate thereof is preferably 90% or more, more preferably 95% or more.

(Polarizing plate winding step)

The winding tension of the laminate (polarizing plate) 4 is 30 N/cm ² to 150 N/cm ² . More preferably, it is 30 N/cm ² to 120 N/cm ² . When it is less than 30 N/cm ² , when the long film is conveyed, the curling occurs and it is not preferable. When it is more than 150 N/cm ² , the winding is too tight, and slack is likely to occur.

Further, the longer the winding length is, the more the winding is too tight under the same tension (the phenomenon that it is difficult to return to a flat state when unwinding), so that the polarizing plate can be wound up to the winding core continuously or at the same time. Sexually weaken the tension. In the method of reducing the tension by such a so-called sharpening operation, the tension therebetween is 150 N/cm ² or less.

The length of the polarizing plate wound on the winding core is not particularly limited, but is 100 m. Above 4000m is preferred.

The diameter of the cylindrical core is preferably from 6 inches to 12 inches. The diameter of the core is preferably as large as possible, and is preferably 11 吋, 12 吋, etc., and when it is too large, it is difficult to transport and store.

Since the material of the cylindrical core is used in a clean room, it is not easy to generate dust. Therefore, it is not particularly limited as long as the appropriate strength for winding a wide polarizing plate can be secured. FRP (glass fiber reinforced plastic) and so on.

Example

The invention is further illustrated by the following examples, but the invention is not limited by the examples.

[Example 1] (production of polarizing film)

A polyvinyl alcohol film "OPL film M-7500 (manufactured by Nippon Synthetic Co., Ltd.)" having a polymerization degree of 2,400, a saponification degree of 99.9 mol%, a thickness of 75 μm, and a width of 3000 mm was used. The extension is performed by driving the rolls before and after the treatment tank with a difference in rotation speed.

First, the film was kept in a state of being stretched without being loosened, and immersed in a swelling tank containing pure water at 30 ° C for 80 seconds to sufficiently swell the film. And when the swelling in the swelling tank, the speed ratio of the inlet and outlet rollers is 1.2. After immersing in a roll, it was immersed in a water dipping tank containing pure water at 30 ° C for 160 seconds. The extension of the mechanical direction in the groove was made 1.09 times.

Next, it was immersed in a dyeing tank containing an aqueous solution of iodine/potassium iodide/water in a weight ratio of 0.02/2.0/100, and uniaxially stretched at a stretching ratio of about 1.5 times. Thereafter, it was further immersed in a boric acid bath containing an aqueous solution of potassium iodide/boric acid/water in a weight ratio of 12/3.7/100 at 55.5 ° C for 130 seconds, from the embryonic membrane to the cumulative stretching ratio. Uniaxial extension is performed 5.7 times. Thereafter, it was further immersed in a boric acid bath containing an aqueous solution of potassium iodide/boric acid/water in a weight ratio of 9/2.4/100 at 40 ° C for 60 seconds.

Thereafter, it was further washed with pure water of 8 ° C in a washing tank for about 16 seconds, and then passed through in a drying furnace of about 60 ° C and then in the order of a drying oven of about 85 ° C. The residence time in the drying oven was dried for a total of 160 seconds. By this operation, a polarizing film having a thickness of 28 μm oriented by iodine adsorption can be obtained.

(production of polarizing plate)

For the transparent film, a cycloolefin resin film "ZEONOR" (manufactured by Zeon Corporation, Japan) having a thickness of 60 μm and 50 μm was prepared.

Then, the epoxy resin composition "KR series" (manufactured by Adeka Co., Ltd.) of an ultraviolet curing type adhesive is applied as an adhesive coating device (Micro Chamber) on one surface of the above-mentioned cycloolefin resin film "ZEONOR" having a thickness of 60 μm. Doctor: manufactured by Fuji Machine Co., Ltd.). At the same time, the epoxy resin composition "KR series" (manufactured by Adeka Co., Ltd.) of an ultraviolet curing type adhesive is applied to the single surface of the cycloolefin resin film "ZEONOR" having a thickness of 50 μm. The device is coated. In the meantime, the moving speed of the polarizing film laminate in the adhesive application device was 25 m/min, and the gravure roll was rotated in the opposite direction to the direction in which the laminated material was conveyed to form a cycloolefin resin film "ZEONOR" having a thickness of 60 μm. The thickness of the adhesive layer was about 3.5 μm, and the thickness of the adhesive layer on the cycloolefin resin film "ZEONOR" having a thickness of 50 μm was about 3.5 μm (total of about 7.0 μm).

Then, the cycloolefin resin film "ZEONOR" having a thickness of 60 μm and a thickness of 50 μm was bonded to each other on the both surfaces of the polarizing film via a roll of the epoxy resin composition (ultraviolet curing type adhesive).

The polarizing film bonded by the above two kinds of transparent films is applied with 600 N/m in the longitudinal direction. The tension was brought into close contact with the cooling roller, and was carried at a moving speed of 25 m/min, and passed through an ultraviolet ray irradiated by two metal halide lamps (manufactured by GS-YUASA Co., Ltd., power of one seat was 120 W/cm). In the first active energy ray irradiation step, the second active energy is passed through the ultraviolet ray irradiated by one of the electrodeless D bulbs ("Light Hammer 10" manufactured by Fusion Co., Ltd., and the electric power of one seat is 216 W/cm). The line irradiation step is performed to produce a polarizing plate.

The electrodeless D-bulb one is a unit formed by arranging six electrodes without an electrode D in the width direction of the film, and is arranged in one row in the longitudinal direction of the film.

When the metal halide lamp is passed through, the cycloolefin resin film "ZEONOR" having a thickness of 50 μm is applied to the outer peripheral surface of the cooling roller set at 23 ° C, and the cycloolefin resin having a thickness of 60 μm is bonded to the outer surface of the cooling roller set at 23 ° C. The side of the film "ZEONOR" is irradiated with ultraviolet rays. In this way, deterioration of the adhesive and the polarizing film is suppressed by the influence of heat in the first active energy ray irradiation step. The surface roughness of the outer peripheral surface of the cooling roller was measured by a surface roughness measuring device (trade name: HANDY-SURF E-35B, manufactured by Tokyo Denshi, Japan), and the maximum surface roughness Ry was 0.8 S.

(surface evaluation of polarizing plate)

The surface of the polarizing plate of Example 1 was visually evaluated, and no wavy undulation was observed. The results are shown in Table 1.

[Embodiment 2]

In the present embodiment, the surface roughness of the outer peripheral surface of the cooling roller was measured by a surface roughness measuring device (trade name: HANDY-SURF E-35B, manufactured by Tokyo Precision Co., Ltd.), and the maximum surface roughness Ry was 4.0 S. A polarizing plate of Example 2 was produced in the same manner as in Example 1 except for the above.

(surface evaluation of polarizing plate)

The surface of the polarizing plate of Example 2 was visually evaluated, and no wavy undulation was observed. The results are shown in Table 1.

[Example 3]

In the present embodiment, the surface roughness of the outer peripheral surface of the cooling roller is measured by a surface roughness measuring device (trade name: HANDY-SURF E-35B, manufactured by Tokyo Dentsu, Japan), and the maximum surface roughness Ry is 10.0S. . A polarizing plate was produced in the same manner as in Example 1 except the above.

(surface evaluation of polarizing plate)

The surface of the polarizing plate was visually evaluated, and no wavy undulation was observed. The results are shown in Table 1.

[Comparative Example 1]

In the comparative example, the surface roughness of the outer peripheral surface of the cooling roller was measured by a surface roughness measuring device (trade name: HANDY-SURF E-35B, manufactured by Tokyo Dentsu, Japan), and the maximum surface roughness Ry was 0.2 S. . A polarizing plate of Comparative Example 1 was produced in the same manner as in Example 1 except the above.

(surface evaluation of polarizing plate)

The surface of the polarizing plate of Comparative Example 1 was visually evaluated, and wavy undulations were observed. The results are shown in Table 1.

From the above results, it is known that the roll used in the first active energy ray irradiation step The maximum height Ry of the surface roughness of the wheel is 0.4 to 12 s, thereby preventing occurrence of surface defects.

(industrial availability)

The polarizing plate of the present invention can be effectively used in various display devices typified by liquid crystal display devices.

1‧‧‧ polarizing film

2, 3‧‧‧ transparent film

4‧‧‧Laminated body (polarizer)

11, 12‧‧‧ adhesive coating device

13‧‧‧Roller (cooling roller)

16, 17, 18, 31, 32‧‧‧Active energy line irradiation device

19‧‧‧Transport rolls

20‧‧‧Wind roller

51, 52‧‧‧ fitted roller

Claims (2)

A method for producing a polarizing plate is a method for producing a polarizing plate in which a transparent film is bonded to one surface or both surfaces of a polarizing film, and sequentially comprises the step of applying an active energy ray-curing type to one surface of the transparent film. An adhesive application step of the adhesive; applying pressure to the laminate of the transparent film on the one surface or both surfaces of the polarizing film via the adhesive layer, thereby bonding the transparent film to the polarizing film And a first active energy ray irradiation step of irradiating the laminate with an active energy ray to cure the adhesive between the laminate and the roller rotating in the transport direction; The maximum roughness Ry of the surface roughness of the above roller is 0.4 to 12S. The method of manufacturing a polarizing plate according to claim 1, wherein the roller is a cooling roller.