TW201331641A - Method for manufacturing polarizing plate - Google Patents

Abstract

Provided is a method for manufacturing a polarizing plate, sequentially comprising a step of applying adhesive by applying an active energy line curable adhesive on one side of a transparent film, or on one-side or two-side of a polarizing film; a step of sticking the transparent film with the polarizing film by holding a laminate made by laminating the transparent film to one-side or two-side of the polarizing film between a pair of sticking rollers that rotate toward the transporting direction, applying a pressure to the laminate; a step of first active energy line radiation by radiating an active energy ling to the laminate and curing the adhesive while the laminate and the rotating rollers that rotating toward the transporting direction are transported in a tightly adhered state; wherein, at least one of the pair of the sticking rollers is a rubber roller having a surface made from rubber and driving by rotation, and the rotating speed of the rotating roller is faster than the rotating speed of the rubber roller.

Description

Method for manufacturing polarizing plate

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

The polarizing film is widely used as a dichroic dye to be adsorbed to a polyvinyl alcohol resin film, and an iodine-based polarizing film containing iodine as a dichroic dye and a dichroic dye as a dichroic dye are known. The dye is a polarizing film or the like. These polarizing films are usually laminated on a single surface or both surfaces of a transparent film such as a triacetyl cellulose film through a bonding agent to form a polarizing plate.

As a method of applying a single-sided or two-area transparent film to a polarizing film, an active energy ray-curable resin is applied to the surface of the transparent film in advance, and then the polarizing film and the transparent film are laminated by a pair of bonding rolls. Then, the active energy ray is irradiated to the splicing and hardening. (For example, refer to Japanese Laid-Open Patent Publication No. 2004-245925 (Patent Document 1), JP-A-2009-134190 (Patent Document 2), and JP-A-2011- Japanese Patent Publication No. 95560 (Patent Document 3).

In Patent Document 3, when the active energy ray-curable resin is irradiated with an active energy ray and cured, the laminate is cured while being in close contact with the outer surface of the roller, thereby suppressing generation of wave curl or the like. However, when the bonding roller and the active energy ray are irradiated, the balance of the rotational speed of the roller which is in close contact with the laminated body may be inappropriate. In the case where the polarizing plate produced is bent into a corrugated plate, the appearance is poor (hereinafter, this state is referred to as "wave plate bending").

[Previous Technical Literature] [Patent Literature]

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

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

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

In the method of the step of curing the active energy ray-curable resin while adhering the laminated body to the outer peripheral surface of the roll as described above, the object of the present invention is to suppress the occurrence of corrugated bending.

The present invention relates to a method for producing a polarizing plate comprising a transparent film bonded to one or both sides of a polarizing film, which is provided in sequence on one side of the transparent film or on one or both sides of the polarizing film. a bonding agent coating step of the active energy ray-curable bonding agent; and the laminating body formed by laminating the transparent film on the one surface or both surfaces of the polarizing film by the bonding agent, and a pair of bonding rollers rotating in the conveying direction And applying a pressure to the laminated body to bond the transparent film to the polarizing film; and when the laminated body is conveyed in a state of being in close contact with the rotating roller rotating in the conveying direction, the laminated body is irradiated a first active energy ray irradiation step of curing the energy ray and curing the bonding agent; wherein at least one of the pair of bonding rollers is a rubber roller having a surface formed by rubber and rotationally driven, and a rotation speed of the rotating roller It is faster than the above rubber roller. The above rotating roller is preferably a cooling roller.

In the above aspect of the invention, the rotation speed of the rotating roller is preferably 100.1 or more and 102.0 or less when the rotation speed of the rubber roller is 100.

According to the present invention, it is possible to produce a polarizing plate which suppresses the occurrence of wave-plate bending and has a good appearance. Therefore, the polarizing plate obtained by the manufacturing method according to the present invention can be provided in a high quality liquid crystal display device.

1‧‧‧ polarizing film

2, 3‧‧‧ transparent film

4‧‧‧Laminated body (polarizer)

11, 12 ‧ ‧ cement coating device

13‧‧‧Rotating roller (cooling roller)

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

19‧‧‧Feed roller

20‧‧‧Winding roller

51, 52‧‧‧ affixing rolls

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 comprising a transparent film bonded to one or both sides of a polarizing film, and is provided in the order of coating active energy on one side of the transparent film or on one or both sides of the polarizing film. a bonding agent coating step of a wire-curable bonding agent; a laminate in which a transparent film is laminated on one surface or both surfaces of a polarizing film by a bonding agent is interposed between a pair of bonding rolls that rotate in a conveying direction, and is laminated When a pressure is applied to the body to adhere the transparent film to the polarizing film; and when the laminated body is conveyed in a state in which the rotating roller is rotated in the conveying direction, the laminated body is irradiated with the active energy ray and the bonding agent is hardened. The first active energy ray irradiation step. Further, at least one of the pair of bonding rolls is a rubber roller having a surface formed by rubber and rotationally driven, and the rotation speed of the rotating roller is faster than a rotation speed of the rubber roller.

First, the requirements for 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 polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and uniaxially stretched. Polyethylene The alcohol resin can be obtained by saponifying a polyvinyl acetate resin. Polyvinyl acetate-based resin In addition to polyvinyl acetate of a single polymer of vinyl acetate, for example, a copolymer of vinyl acetate and other monomers copolymerizable therewith (for example, an ethylene-vinyl acetate copolymer) may be mentioned. Wait. Other monomers copolymerizable with vinyl acetate may, for example, be unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, acrylamides having an ammonium group, and the like. The degree of saponification of the polyvinyl alcohol-based resin is 85 mol% or more, more preferably 90 mol% or more, and still more desirably 98 to 100 mol%. The average degree of polymerization of the polyvinyl alcohol-based resin is usually from 1,000 to 10,000, more preferably from 1,500 to 5,000. These polyvinyl alcohol-based resins may be modified, and for example, aldehyde-modified polyethylene formaldehyde, polyvinyl acetaldehyde, polyvinyl butyral or the like may be used.

A film made of such a polyvinyl alcohol-based resin is used as a raw material film of a polarizing film. The film forming method of the polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventionally known method. The film thickness of the raw material film composed of the polyvinyl alcohol-based resin is not particularly limited, but is, for example, about 10 to 150 μm. The thickness is usually supplied in the form of a roll of 20 to 100 μm, more preferably 30 to 80 μm, and an industrially practical width of 500 to 6000 mm.

Commercially available polyvinyl alcohol-based film (Vinylon VF-PS #7500, Kuraray/OPL film M-7500, manufactured by Nippon Synthetic Co., Ltd.) has a raw material thickness of 75 μm (Vinylon VF-PS #6000, manufactured by Kuraray). , Vinylon VF-PE #6000, manufactured by Kuraray) The thickness of the raw material is 60 μm.

The polarizing film is usually a step of adsorbing a dichroic dye by dyeing a polyvinyl alcohol-based resin film to a dichroic dye (dyeing step), and a polyvinyl alcohol-based resin film having a dichroic dye adsorbed thereon as boric acid. a step of aqueous solution treatment (boric acid treatment step), and a step of washing with water after treatment with the aqueous boric acid solution (washing place) Manufactured according to the steps).

Further, in the production of the polarizing film, the polyvinyl alcohol-based resin film is usually uniaxially stretched, and the uniaxial stretching may be performed before the dyeing treatment step, or may be carried out in the dyeing treatment step or after the dyeing treatment step. The uniaxial stretching is carried out after the dyeing treatment step, which may be carried out before the boric acid treatment step or in the boric acid treatment step. Of course, uniaxial stretching can be performed at these complex stages.

Uniaxial extension allows for uniaxial extension between rolls of varying speeds or uniaxial extension with hot rolls. Further, it may be a dry stretching which is extended in the atmosphere, or may be a wet stretching which is extended in a state of being swollen by a solvent. The stretching ratio is usually from 3 to 8 times.

In the dyeing treatment step, the polyvinyl alcohol-based resin film is dyed by a dichroic dye, for example, by immersing the polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. As the dichroic dye, for example, iodine, a dichroic dye or the like is used. The dichroic dye contains, for example, a dichroic direct dye composed of a bisazo compound such as C.I. Direct Red 39, a dichroic direct dye composed of a compound such as trisazo or tetrazo. Further, the polyvinyl alcohol-based resin film is preferably subjected to water immersion treatment before the dyeing treatment.

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

On the other hand, in the case where a dichroic dye is used as the dichroic dye, a method in which a polyvinyl alcohol-based resin film is immersed in an aqueous solution containing an aqueous dichroic dye and dyed is usually used. The content of the dichroic dye of the aqueous solution is usually from 1 × 10 ^-4 to 10 parts by weight, more preferably from 1 × 10 ^-3 to 1 part by weight, particularly preferably from 1 × 10 ^-3 to 100 parts by weight per 100 parts by weight of water. 1 × 10 ^-2 parts by weight. The aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. In the case where a dichroic dye is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually from 20 to 80 ° C, and the immersion time (dyeing time) for the aqueous solution is usually from 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 containing an aqueous solution of boric acid is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. In the case where iodine is used as the dichroic dye in the dyeing treatment step, the aqueous solution containing boric acid used in the boric acid treatment step preferably contains potassium iodide. In this case, the amount of potassium iodide in the aqueous solution containing boric acid is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. The immersion time in an aqueous solution containing boric acid is usually from 60 to 1200 seconds, more preferably from 150 to 600 seconds, still more preferably from 200 to 400 seconds. The temperature of the aqueous solution containing boric acid is usually 40 ° C or higher, more preferably 50 to 85 ° C, still more preferably 55 to 75 ° C.

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

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

(transparent film)

In the present invention, a transparent film is bonded to one surface or both surfaces of the above polarizing film. The material constituting the transparent film may, for example, be a cycloolefin resin, a cellulose acetate resin, or a polycondensation such as polyethylene terephthalate or polyethylene naphthalate or polybutylene terephthalate. As the ester resin, the polycarboxylate resin, the acrylic resin, the polypropylene, or the like, a film material widely used in the region can be used. In the case where the transparent film is bonded to both sides of the polarizing film, the respective transparent films may be the same or different types of films.

The cycloolefin-based resin is a thermoplastic resin (also referred to as a thermoplastic cycloolefin resin) having a unit of a monomer composed of a cyclic olefin (cycloolefin) such as a norbornene or a polycyclic norbornene-based 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 cycloolefins, or a cycloolefin, a chain olefin, or an aromatic compound having a vinyl group. Addition polymer. Moreover, it is also effective to introduce a polar base.

In the case of using a copolymer of a cyclic olefin and a chain olefin or/and an aromatic compound having a vinyl group, the chain olefin may, for example, be ethylene or propylene, and examples of the aromatic compound having a vinyl group include benzene. Ethylene, α-methylstyrene, nuclear alkyl-substituted styrene, and the like. In such a copolymer, the unit of the monomer composed of the cyclic olefin may be 50 mol% or less (more desirably 15 to 50 mol%). In particular, in the case of using a terpolymer of a cyclic olefin, a chain olefin, and an aromatic compound having a vinyl group, the unit of the monomer composed of the cyclic olefin may be in a small amount as described above. to In such a terpolymer, a unit of a monomer composed of a chain olefin is usually 5 to 80 mol%, and a unit of a monomer having a vinyl aromatic compound is usually 5 to 80 mol%.

For the cycloolefin-based resin, a commercially available product such as Topas (manufactured by Ticona Co., Ltd.), Arton (manufactured by JSR Co., Ltd.), ZEONOR (manufactured by Nippon Zeon Co., Ltd.), ZEONEX (manufactured by Nippon Zeon Co., Ltd.), and APL can be used. (made by Mitsui Chemicals Co., Ltd.), OXIS (made by Okura Industrial Co., Ltd.), etc. When such a film of a cycloolefin resin is used as a film, a conventional method such as a solvent cast film method or a melt extrusion method is suitably used. Further, for example, a film made of a cycloolefin-based resin which has been previously formed into a film such as Escena (manufactured by Sekisui Chemical Co., Ltd.), SCA40 (manufactured by Sekisui Chemical Co., Ltd.), ZEONOR film, (manufactured by Optes Co., Ltd.), or the like can be used. Commercial products.

The cycloolefin-based resin film may be a uniaxially stretched or a biaxially stretched. Any phase difference value which can be imparted to the cycloolefin-based resin film can be imparted by stretching. The stretching is generally performed while continuously winding up the film roll, and is extended in the heating furnace toward the traveling direction of the roll (the longitudinal direction of the film), the direction perpendicular to the traveling direction (the width direction of the film), or both. The temperature of the heating furnace is usually in the range from the vicinity of the glass transition temperature of the cycloolefin-based resin film to the glass transition temperature + 100 °C. The stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.

When the cycloolefin-based resin film is wound into a roll, the film tends to be agglomerated after being adhered to each other. Therefore, the protective film is usually bonded and then wound into a roll. Further, since the cycloolefin resin film generally has poor surface activity, it is preferred to subject the surface to be bonded to the polarizing film to a surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment or saponification treatment. Among them, it is suitable for plasma processing which is easy to implement, especially atmospheric piezoelectric slurry treatment and corona treatment.

The cellulose acetate-based resin refers to a partially or completely esterified product of cellulose, and examples thereof include a film composed of cellulose acetate, propionate, butyrate, or a mixed ester thereof. More specifically, for example, a triacetyl cellulose film, a diethyl fluorene cellulose film, a cellulose acetate propionate film, a cellulose acetate butyrate film, or the like can be given. Such a cellulose ester-based resin film can be suitably used in a commercially available product, for example, Fujitac TD80 (manufactured by Fujifilm Co., Ltd.), Fujitac TD80UF (manufactured by Fujifilm Co., Ltd.), and Fujitac TD80UZ (manufactured by Fujifilm Co., Ltd.). KC8UX2M (Konica Minolta Opto Co., Ltd.), KC8UY (Konica Minolta Opto Co., Ltd.), Fujitac TD60UL (made by Fujifilm Co., Ltd.), KC2UYW (Konica Minolta Opto Co., Ltd.), KC4UAW (Konica Minolta Opto) Co., Ltd.), KC6UAW (manufactured by Konica Minolta Opto Co., Ltd.), etc.

Further, as the transparent film, a cellulose acetate resin film which imparts a phase difference is also suitably used. For example, WV BZ 438 (made by Fujifilm Co., Ltd.), KC4FR-1 (Konica Minolta Opto Co., Ltd.), and KC4CR-1 (Konica Minolta) are commercially available as a commercial product of the cellulose acetate-based resin film. Opto Co., Ltd.), KC4AR-1 (manufactured by Konica Minolta Opto Co., Ltd.), and the like. Cellulose acetate is also known as acetaminophen, cellulose acetate.

These cellulose acetate-based films are easily absorbed by water, and the moisture content of the polarizing plate affects the relaxation of the ends of the polarizing plates. The water content at the time of manufacturing the polarizing plate is closer to the storage environment of the polarizing plate. For example, the balance of the moisture content of the production line of the clean room and the storage warehouse of the roll is better, although it is also related to the composition of the laminated film, but the moisture rate is, for example. It is from 2.0 to 3.5%, more preferably from 2.5% to 3.0%. The numerical value of the moisture content of the polarizing plate was measured by the dry weight method and was a change in weight after 105 ° C / 120 minutes.

The thickness of the transparent film used in the present invention is preferably thin, and when it is too thin, the strength is lowered and the workability is deteriorated. On the other hand, when it is too thick, there arises a problem that the transparency is lowered, and the curing time required after lamination is lengthened. Therefore, a suitable thickness of the transparent film is, for example, 5 to 200 μm, more preferably 10 to 150 μm, still more preferably 10 to 100 μm.

In order to improve the bonding property between the bonding agent and the polarizing film and/or the transparent film, the polarizing film and/or the transparent film may be subjected to corona treatment, flame treatment, plasma treatment, ultraviolet treatment, primer coating treatment, saponification. Surface treatment such as processing.

Further, the transparent film may be used alone or in combination of two or more kinds to perform surface treatment such as anti-glare treatment, anti-reflection treatment, hard coating treatment, antistatic treatment, and anti-stain treatment. Further, the transparent film and/or the transparent film surface protective layer may contain a plasticizer such as a diphenyl ketone compound or a benzotriazole compound, a phenyl phosphate compound or a phthalate compound. Agent.

Further, the transparent film may have a function as a retardation film, a function as a luminance enhancement film, a function as a reflective film, a function as a semi-transmissive reflective film, a function as a diffusion film, a function as an optical compensation film, and the like. Optical function such as optical function. In this case, for example, an optical functional film such as a surface layer retardation film of a transparent film, a brightness enhancement film, a reflective film, a transflective film, a diffusion film, or an optical compensation film may have such a function. It is also possible to impart 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 as a luminance enhancement film.

For example, the above-mentioned transparent film is subjected to the stretching treatment as described in Japanese Patent No. 2841377, Japanese Patent No. 3094113, or the like, or the processing described in Japanese Patent No. 3168850, whereby the function as a retardation film can be imparted. The phase difference characteristic of the phase difference film, for example, the front phase difference value can be appropriately selected to be 5 to The difference in phase between 100 nm and the thickness direction is in the range of 40 to 300 nm and the like. Further, in the above transparent film, fine pores are formed by a method as described in JP-A-2002-169025 or JP-A-2003-29030, or the center wavelengths of the selective selective reflection are different. Two or more layers of the cholesteric liquid crystal layer can provide a function as a brightness enhancement film.

When the transparent film is formed into a metal thin film by vapor deposition, sputtering, or the like, it can be provided as a reflective film or a semi-transmissive reflective film. The resin film containing fine particles is applied to the above transparent film, whereby the function as a diffusion film can be imparted. In addition, a liquid crystal compound such as a discotic liquid crystalline compound is applied to the transparent film to be aligned, thereby imparting a function as an optical compensation film. Moreover, the transparent film may contain a compound exhibiting a phase difference. Further, various optical functional films can be directly bonded to the polarizing film using a suitable bonding agent. For the commercially available product of the optical functional film, for example, a brightness improving film such as DBEF (available from 3M Company, obtained from Sumitomo 3M Co., Ltd.), and a viewing angle improving film such as WV film (made by Fujifilm Co., Ltd.), Arton film (manufactured by JSR Co., Ltd.), ZEONOR film (manufactured by Optes Co., Ltd.), Escena (manufactured by Sekisui Chemical Co., Ltd.), VA-TAC (manufactured by Konica Minolta Opto Co., Ltd.), SUMICALITE (Sumitomo Chemical Co., Ltd.) A phase difference film such as a company).

(active energy ray hardening type bonding agent)

The polarizing film and the transparent film are bonded together by an active energy ray-curable bonding agent. The active energy ray-curable bonding agent is composed of an epoxy resin-based resin composition containing an epoxy resin which is cured by irradiation with an active energy ray, from the viewpoints of weather resistance, refractive index, durability, and the like. Adhesive. However, the present invention is not limited thereto, and various active energy ray-curable bonding agents (organic solvents) used in the manufacture of conventional polarizing plates can be used. A bonding agent, a hot-melt bonding agent, a solventless bonding agent, or the like) may be, for example, an acrylic resin resin composition such as acrylamide, acrylate, urethane acrylate or acrylate acrylate. Agents, etc.

The epoxy resin refers to a compound having two or more epoxy groups in the 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 bonding agent is preferably an epoxy resin containing no aromatic ring in the molecule (for example, refer to the patent literature) 1). Examples of such an epoxy resin include a hydrogenated epoxy resin, an alicyclic epoxy resin, and an aliphatic epoxy resin.

The nuclear hydrogenation polyhydroxy compound can be obtained by selectively performing a nuclear hydrogenation reaction under pressure in the presence of a catalyst to obtain a nuclear hydrogenation polyhydroxy compound ring by a polyhydroxy compound of a raw material of an aromatic epoxy resin under pressure. A method of oxypropyl etherification to obtain a hydrogenated epoxy resin. Examples of the aromatic epoxy resin include bisphenol epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diepoxypropyl ether of bisphenol S; Phenolic novolak epoxy resin, cresol novolac epoxy resin and phenolic epoxy resin such as hydroxybenzaldehyde phenol novolac epoxy resin; epoxypropyl ether of tetrahydroxyphenylmethane, tetrahydroxydiphenyl ketone A polyfunctional epoxy resin such as a epoxidized propyl ether or an epoxidized polyvinyl phenol. More preferably, the hydrogenated epoxy resin is a glycidyl ether of hydrogenated bisphenol A.

The alicyclic epoxy resin refers to an epoxy resin having one or more epoxy groups bonded to an alicyclic ring in the molecule. The "epoxy group bonded to the alicyclic ring" means the oxygen atom -O- of the bridge of the structure shown by the following formula. In the following formula, m is an integer of 2 to 5.

The group in which the form of one or a plurality of hydrogen atoms in the above formula (CH ₂ ) _m is bonded to a compound having another chemical structure can be an alicyclic epoxy resin. One or a plurality of hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group such as a methyl group or an ethyl group. In the alicyclic epoxy resin, since it exhibits good adhesion, it is preferred to use an epoxy resin having an oxabicyclohexane ring (the above formula m=3) and an oxabicycloheptane ring (described above). Epoxy resin of the formula m=4). Hereinafter, the alicyclic epoxy resin which is preferably used is specifically exemplified, but is not limited to these compounds.

(a) Epoxycyclohexanecarboxylic acid epoxycyclohexyl methyl ester represented by the following formula (I):

(wherein R ¹ and R ² independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(b) an epoxycyclohexanecarboxylic acid ester of an alkanediol represented by the following formula (II):

(wherein R ³ and R ⁴ independently of each other 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 independently of each other 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) Epoxycyclohexyl methyl ether of polyethylene glycol represented by the following formula (IV):

(wherein R ⁷ and R ⁸ each independently 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 independently of each other 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 diepoxytrispirocyclic compound represented by the following formula (VI):

(wherein R ¹¹ and R ¹² independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(g) a diepoxymonospirocyclic compound represented by the following formula (VII):

(wherein R ¹³ and R ¹⁴ independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(h) a vinylcyclohexene diepoxide represented by 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 independently of each other represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(j) a dicyclooxytricyclodecane represented by 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 commercially available or the like, and it is preferred to use them because of their ease of use and the like.

(A) an ester of 7-oxabicyclo[4.1.0]heptane-3-carboxylic acid with (7-oxa-bicyclo[4.1.0]heptan-3-yl)methanol [in the 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-oxa-bicyclo[ 4.1.0]Hept-3-yl)methanol ester [In the formula (I), R ¹ =4-CH ₃ , R ² =4-CH ₃ compound], (C) 7-oxabicyclo[4.1 .0] an esterified product of heptane-3-carboxylic acid and 1,2-ethanediol [in the formula (II), a compound of R ³ = R ⁴ = H, n = 2], (D) (7-oxygen) An ester of heterobicyclo[4.1.0]heptan-3-yl)methanol with adipic acid [in the formula (III), R ⁵ =R ⁶ =H, p=4 compound], (E) (4-A An ester of -7-oxabicyclo[4.1.0]heptan-3-yl)methanol with adipic acid [in the formula (III), R ⁵ =4-CH ₃ , R ⁶ =4-CH ₃ ,p a compound of =4, (F) (7-oxabicyclo[4.1.0]heptan-3-yl)methanol and an etherified product of 1,2-ethanediol [in the formula (V), R ⁹ =R ¹⁰ =H, compound of r=2].

Further, the aliphatic epoxy resin may, for example, be a polyepoxypropyl ether of an aliphatic polyol or an alkylene oxide adduct thereof. More specifically, it may be a di-epoxypropyl ether of 1,4-butanediol; a di-epoxypropyl ether of 1,6-hexanediol; a triepoxypropyl ether of glycerol; a trihydroxyl Triepoxypropyl ether of methyl propane; diepoxypropyl ether of polyethylene glycol; diepoxypropyl ether of propylene glycol; addition of aliphatic polyols such as ethylene glycol, propylene glycol and glycerol Polyepoxypropyl ether of a polyether polyol obtained by using two or more kinds of alkylene oxides (ethylene oxide or propylene oxide).

The epoxy resin constituting the bonding agent made of the epoxy resin composition may be used alone or in combination of two or more. Ring of epoxy resin used in the composition The oxygen equivalent weight is usually in the range of 30 to 3,000 g/equivalent, more desirably in the range of 50 to 1,500 g/equivalent. When the epoxy equivalent is less than 30 g/equivalent, there is a possibility that the flexibility of the composite polarizing plate after curing is lowered and the joint strength is lowered. On the other hand, when it exceeds 3,000 g / equivalent, there is a possibility that the compatibility with other components contained in the bonding agent is lowered.

Among the binders, from the viewpoint of reactivity, it is preferred to use a cationic polymerization for the hardening reaction of the epoxy resin. Therefore, as the curable epoxy resin of the active energy ray-curable bonding agent, it is preferred to incorporate a cationic polymerization initiator. The cationic polymerization initiator is irradiated with an active energy ray such as visible light, ultraviolet rays, X-rays, electron beams or the like to generate a cationic species or a Lewis acid, and initiates polymerization of an epoxy group. Hereinafter, a cationic polymerization initiator which generates a cationic species or a Lewis acid by the irradiation of an active energy ray and initiates polymerization of an epoxy group is referred to as a "photocationic polymerization initiator".

The method of curing the bonding agent by irradiation with an active energy ray using a photocationic polymerization initiator can be hardened at room temperature to reduce the necessity of considering the heat resistance of the polarizing film or bending due to expansion, and can be used in the film. It is advantageous to have a good joint between them. Further, the photocationic polymerization initiator is subjected to a catalyst action by light, and is excellent in storage stability and workability even when it is mixed with an epoxy resin.

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-arene complex or the like.

Examples of the aromatic diazonium salt include benzene diazonium hexafluoroantimonate, benzene diazonium hexafluorophosphate, and benzene diazonium hexafluoroborate. Further, examples of the aromatic onium salt include diphenylphosphonium sulfonium (pentafluorophenyl)borate, diphenylphosphonium hexafluorophosphate, diphenylphosphonium hexafluoroantimonate, and bis(4-fluorophosphate). Nonylphenyl) phosphonium salt and the like.

The aromatic sulfonium salt may, for example, be a triphenylsulfonium hexafluorophosphate or a triphenyl hexafluoroantimonate. Base salt, triphenylsulfonium tetrakis(pentafluorophenyl)borate, bis(hexafluorophosphate) 4,4'-bis(diphenylphosphonium) diphenyl sulfide, bis(hexafluoroantimonate) 4, 4'-bis[bis(?-hydroxyethoxy)phenylhydrazine]diphenyl sulfide, bis(hexafluorophosphate) 4,4'-bis[bis(?-hydroxyethoxy)phenylhydrazine] Phenyl sulfide, hexafluoroantimonate 7-[bis(p-tolyl)purine]-2-isopropylthioxanthone, tetrakis(pentafluorophenyl)borate 7-[di(p-toluene)鋶]-2-isopropylthioxanthone, 4-phenylcarbonyl-4'-diphenylfluorene-diphenyl sulfide hexafluorophosphate, 4-(p-butyl hexafluoroantimonate) Phenylcarbonyl)-4'-diphenylfluorene-diphenyl sulfide, tetrakis(pentafluorophenyl)borate 4-(p-t-butylphenylcarbonyl)-4'-di(p-tolyl)鋶-diphenyl sulfide and the like.

Further, examples of the iron-aromatic complex include, for example, xylene hexafluoroantimony-cyclopentadienyl iron (II), cumene hexafluoro-cyclopentadienyl iron (II), and xylene-cyclopentane. Iron (II)-tris(trifluoromethylsulfonyl)methanide (xylene-cyclopentadienyliron(II) tris(trifluoromethylsulfonyl)methanide).

Commercially available products of the photocationic polymerization initiators can be easily obtained, and for example, "KAYALITE PCI-220" and "KAYALITE PCI-620" (the above are manufactured by Nippon Kayaku Co., Ltd.) are listed under the respective trade names; UVI-6990" (made by Union Carbide), "ADEKA OPTOMER SP-150" and "ADEKA OPTOMER SP-170" (above ADEKA Co., Ltd.); "CI-5102", "CIT-1370", CIT-1682", "CIP-1866S", "CIP-2048S" and "CIP-2064S" (above is made by Japan Soda Co., Ltd.); "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" (above) "PI-2074" (made by Rhodia Corporation).

The photocationic polymerization initiator may be used alone or in combination of two or more. Among them, the aromatic onium salt has an ultraviolet absorbing property in a wavelength region of 300 nm or more, and is excellent in curability, and can provide a cured product having good mechanical strength and joint strength. Therefore, an aromatic onium salt is preferably used.

The blending amount of the photocationic polymerization initiator is usually 0.5 to 20 parts by weight, more preferably 1 part by weight or more, and more desirably 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 insufficient, and the mechanical strength and the joint strength tend to be lowered. In addition, 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 increases, the hygroscopic property of the cured product becomes high, and the durability is lowered. The possibility.

In the case of using a photocationic polymerization initiator, the curable epoxy resin composition may further contain a photosensitizer as needed. By using a photosensitizer, the reactivity of cationic polymerization can be improved, and the mechanical strength and joint strength of the cured product can be improved. 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 halide, a photoreductive dye, and the like.

More specific examples of the photosensitizer include, for example, benzoin methyl ether, benzoin isopropyl ether, and benzoin derivatives such as α,α-dimethoxy-α-phenylacetophenone; diphenyl ketone, 2, 4-dichlorodiphenyl ketone, methyl phthalate benzoate, 4,4'-bis(dimethylamino)diphenyl ketone and 4,4'-bis(diethylamino) Diphenyl ketone derivatives such as diphenyl ketone; thioxanthone derivatives such as 2-chlorothiazinone and 2-isopropylthioxanthone; 2-chloroindole and 2-methylindole Anthracene derivatives; acridone derivatives such as N-methylacridone and N-butylacridone; others such as α,α-diethoxyacetophenone, diphenylethylenedione, Fluorenone, Xanthone, uranium compounds, Halogen and the like. 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 bonding agent is hardened by photocationic polymerization, and can be hardened by both photocationic polymerization and thermal cationic polymerization. In the latter case, it is preferred to use a photocationic polymerization initiator and a thermal cationic polymerization initiator together.

The thermal cationic polymerization initiator may, for example, be a benzyl sulfonium salt, a thiophenium salt, a thiolanium salt, a benzyl ammonium salt, a pyridinium salt, a hydrazinium salt, a carboxylic acid ester or a sulfonate. , amine imine and the like. These thermal cationic polymerization initiators can be easily obtained as a commercial product, and, for example, "Adeka opton CP77" and "Adeka opton CP66" (above, ADEKA Co., Ltd.), "CI- 2639" and "CI-2624" (the above are made by Japan's Soda Co., Ltd.), "Sunaid SI-60L" and "Sunaid SI-80L" and "Sunaid SI-100L" (the above are Sanxin Chemical Industry Co., Ltd.) Limited company system) and so on.

The active energy ray-curable bonding agent may contain a compound which promotes cationic polymerization such as oxetane or polyol.

The oxetane is a compound having a 4-membered cyclic ether in the molecule, and examples thereof include 3-ethyl-3-hydroxymethyloxetane and 1,4-bis[(3-ethyl-3-). Oxecyclobutyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, bis[(3-ethyl-3-oxetanyl) Methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, phenol novolac oxetane, and the like. These oxetane can be easily obtained as a commercial product, and can be exemplified by the respective trade names "Aron oxetane OXT-101", "Aron oxetane OXT-121", "Aron oxetane OXT-211", "Aron oxetane OXT-221" and "Aron oxetane OXT-212" (manufactured by Toagosei Co., Ltd.). The oxetanes usually have a ratio of 5 to 95% by weight, preferably 30 to 70% by weight, based on the curable epoxy resin composition.

The polyol is preferably one which does not have an acidic group other than a phenolic hydroxyl group, for example, a polyol compound having no functional group other than a hydroxyl group, a polyester polyol compound, a polycaprolactone polyol compound, and a polyphenolic hydroxyl group. An alcohol compound, a polycarbonate polyol, or the like. The molecular weight of these polyols is usually 48 or more, more preferably 62 or more, still more preferably 100 or more, and still more preferably 1,000 or less. These polyols usually contain 50% by weight or less, and more preferably 30% by weight or less, in the curable epoxy resin composition.

In the active energy ray-curable bonding agent, an ion trapping agent, an antioxidant, a chain transfer agent, an adhesion-imparting agent, a thermoplastic resin, a filler, a flow regulator, a leveling agent, a plasticizer, and a defoaming agent may be further blended. Additives such as agents. The ion scavenger may, for example, be a powdery lanthanoid, lanthanide, magnesium, aluminum, calcium, titanium or inorganic compound such as these mixed systems, and examples of the antioxidant include hindered phenol antioxidants.

As the active energy ray-curable bonding agent, a solventless bonding agent which does not substantially contain a solvent component can be used, and a solvent for adjusting the viscosity can be contained in order to have a suitable viscosity range for each coating method. The solvent is preferably an organic solvent such as a hydrocarbon represented by toluene or an ester represented by ethyl acetate, which does not lower the optical characteristics of the polarizing film and can dissolve the epoxy resin composition well. The viscosity of the active energy ray-curing type bonding agent used in the present invention is, for example, in the range of about 5 to 1000 mPa ‧ s, more preferably 10 to 200 mPa ‧ s, and still more desirably 20 to 100 mPa ‧ s

<Method of Manufacturing Polarizing Plate>

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

The manufacturing apparatus of the polarizing plate shown in Fig. 1 is sequentially disposed along the conveying direction: the bonding agent coating means 11, 12 for applying the bonding agent on one side of the transparent films 2, 3; for bonding the transparent film 2, 3, a bonding roll (nip roll) 51, 52 of the laminated body 4 with the polarizing film 1, a rotating roll 13 which closes the laminated body 4, and a position which is provided on the outer circumferential surface of the rotating roll 13 1 active energy ray irradiation devices 31 and 32; second active energy ray irradiation devices 16 to 18 provided on the downstream side in the transport direction of the first active energy ray irradiation devices 31 and 32; and a transport nip roller 19.

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

Then, the transparent film 2 and 3 coated with the bonding agent are laminated on both surfaces of the polarizing film 1 which is continuously drawn in a state of being wound into a roll to form a laminated body, and the laminated body is rotated in the conveying direction. In a state between the pair of bonding rollers 51 and 52, at least one of the bonding rollers is pressed in the direction of the other bonding roller, and the laminated body is pressed to apply the polarizing film 1 and the transparent film 2, 3 Combine to form a laminate 4 (a bonding step).

In the process of transporting the laminated body 4 to the outer peripheral surface of the rotating roll 13, the active energy ray is irradiated to the outer peripheral surface of the rotating roll 13 from the first active energy ray irradiation devices 31 and 32, and the bonding is performed. Polymerization hardening (first active energy ray irradiation step).

In addition, the second and subsequent 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 bonding agent (second active energy ray irradiation step), and may be added or omitted as necessary. Finally, the laminated body 4 is transported. The nip roller 19 is taken up as a polarizing plate on the take-up reel 20 as a polarizing plate. The steps are described in detail below.

(bonding agent coating step)

The method of applying the bonding agent to the transparent films 2 and 3 is not particularly limited, but for example, a doctor blade, a wire bar, a slit coating method, a comma coater, or a gravure coating method can be used. Various coating methods. Among them, the bonding agent coating devices 11 and 12 are preferably crown rolls in consideration of film coating, degree of freedom of path lines, wide correspondence, and the like. .

In the case where the crown roller is used as the bonding agent coating device 11, 12 and the bonding agent is applied, the thickness (coating thickness) of the applied bonding agent is desirably about 0.1 to 10 μm, more desirably 0.2 μm to 4 μm. The coating thickness of the bonding agent is adjusted in accordance with the ratio of the ratio of the speed of the crown roller to the line speed of the transparent film. In general, the draw ratio (speed/linear velocity of the crown roll) is adjusted to 0.5 to 10, and the coating thickness of the adjustable bond is about 0.1 to 10 μm. More specifically, the linear speed of the transparent films 2, 3 is 10 to 100 m/min, and the crown roll is rotated in the opposite direction to the conveying direction of the transparent films 2, 3, and the speed of the crown roll is 5 to 1000 m/min. The coating thickness of this adjustable bonding agent is about 0.1 to 10 μm.

After the bonding agent is prepared, it is usually at a predetermined temperature of 15 to 40 ° C ± 5 ° C (for example, 30 ° C ± 5 ° C when the temperature is 30 ° C), more preferably ± 3 ° C, more preferably adjusted Coating in an environment of ±1 °C.

(Fitting step)

In this step, the transparent films 2 and 3 of the bonding agent are applied by the above steps by laminating both surfaces of the polarizing film 1 continuously drawn from the roll to the roll. The laminated body is sandwiched between a pair of bonding rollers 51, 52 that rotate in the conveying direction In the state, for example, the bonding roller 51 is pressed in the direction of the bonding roller 52, whereby the polarizing film 1 and the transparent films 2 and 3 are bonded together to form the laminated body 4. In this case, the surface of the transfer roller between the bonding rolls and the surface in the direction in which the vertical bonding rolls are pressed is an angle within a range of ±3°, preferably an angle within a range of ±1°, and particularly preferably perpendicular to the extrusion. The faces of the directions overlap. Thereby, the polarizing film and the transparent film are brought into contact before the bonding roller without generating bubbles.

In addition, in the first drawing, the bonding agent is uniformly applied to one surface of the transparent films 2 and 3, and the bonding surface of the transparent films 2 and 3 is overlapped with the polarizing film 1 and attached by the bonding rolls 51 and 52. In the method, the bonding agent may be uniformly applied to both surfaces of the polarizing film 1, and the bonding surface of the polarizing film 1 and the transparent films 2 and 3 may be overlapped and bonded by the bonding rolls 51 and 52.

The material of the bonding rolls 51 and 52 may be a metal roll or a rubber roll whose surface is made of rubber. At least one of the pair of bonding rollers 51, 52 is a rubber roller having a surface formed by rubber and rotationally driven. In the manufacturing apparatus shown in Fig. 1, for example, the lower roller 52 may be a rubber roller. Generally, the rotational speed of the rotationally driven rubber roller coincides with the linear velocity of the laminate passing between the pair of bonding rollers. It is preferable that the other side bonding roller use a metal roller which can follow the line motion of the laminated body or be rotationally driven. The rotation speed of the rubber roller is, for example, 10 to 50 m/min.

The base material of the metal roll can be made of various conventional materials, and is preferably SUS304. More preferably, the surface of the metal roll is subjected to chrome plating. Further, the material of the rubber roller is not particularly limited, and examples thereof include EPDM, NBR (nitrile rubber), urethane, Titan, polyfluorene, and the like. The hardness of the rubber roller is not particularly limited and is usually from 60 to 100 °, more preferably from 85 to 95 °. Further, the hardness of the rubber roll can be measured by a hardness tester according to JIS K6253. A commercially available hardness tester is, for example, a rubber hardness manufactured by ASKA Corporation. Count "A type" and so on. Specifically, when the surface was pressed with a rod, the surface resistance of the rubber roller was measured by a durometer.

The pressure applied to the laminated body by the metal roll and the rubber roll is preferably 0.5 to 3.0 MPa, more preferably 0.7 to 2.3 MPa, for the two-piece press box (for ultra low pressure) made of Fujifilm. The diameter of the bonding rolls 51 and 52 is not particularly limited and is usually 50 to 400 mm. Further, the diameters of the two (a pair of) bonding rolls 51, 52 may be the same or different.

(first active energy ray irradiation step)

The outer circumferential surface of the roller 13 is formed as a convex curved surface of the mirror surface, and the surface thereof is conveyed while being in close contact with the laminated body 4, and the bonding agent is polymerized and hardened by the active energy ray irradiation devices 31 and 32 in the process. The diameter of the roller 13 is not particularly limited as long as the bonding agent is polymerized and hardened and the laminated body 4 is sufficiently adhered. The rotating roller 13 is driven at a rotational speed faster than the rotational speed of the rubber roller that is rotationally driven by the pair of bonding rollers 51, 52. When the rotational speed of the rubber roller that rotationally drives the pair of bonding rollers 51 and 52 is 100, the rotational speed of the rotating roller 13 is preferably 100.1 or more and 102.0 or less, more preferably 100.1 to 101.5. When the thickness is less than 100.1, the laminated body is prone to wave curling. On the other hand, when it exceeds 102.0, there is a possibility that the film and the roller slide and cause damage or the like.

The rotational speed of the rotating roller 13 is, for example, 10 to 50 m/min. The rotation speed of the rotating roller 13 is not necessarily controlled to be constant, and can be appropriately controlled, for example, in accordance with the type of the film and the slipperiness of the surface of the roll, while confirming the occurrence of the wave-plate bending.

Further, when the polymerization is hardened by irradiation of the active energy ray, the rotating roller 13 acts as a cooling roller for exothermic heat generated by the laminated body 4. At this time, the surface temperature of the cooling roll is desirably set to 4 to 30 °C.

The light source used for the polymerization hardening of the bonding agent by irradiation with the active energy ray is not It is particularly limited, but is preferably a light source having a light-emitting distribution of a wavelength of 400 nm or less. Such a light source may, for example, be 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, or a metal halide lamp. In the first active energy ray irradiation step, the irradiation of the active energy ray is preferably carried out in plural times. In the first drawing, the irradiation of the active energy ray is performed twice, that is, two light sources (the active energy ray irradiation devices 31 and 32) are arranged along the transport direction of the laminated body.

The light irradiation intensity of the active energy ray-curable adhesive is determined by the composition of each of the bonding agents, and is not particularly limited, and is preferably from 10 to 5,000 mW/cm ² . When the light irradiation intensity of the resin composition is less than 10 mW/cm ² , the reaction time becomes too long, and when it exceeds 5000 mW/cm ² , the bonding agent may be generated due to heat radiated from the lamp and heat generation during polymerization of the composition. The yellowing of the epoxy resin composition or the like of the constituent material and the deterioration of the polarizing film. Further, the irradiation intensity is preferably an intensity of a wavelength region in which the photocationic polymerization initiator is activated, more preferably a wavelength region having a wavelength of 400 nm or less, and more preferably a wavelength region having a wavelength of 280 to 320 nm.

In the case where the active energy ray is ultraviolet ray, in the step of irradiating the laminated body 4 with the active energy ray, it is preferable to apply a tension of 100 to 800 N/m in the longitudinal direction (transport direction) of the laminated body 4, so that the irradiation time is The laminated body 4 is conveyed at a linear velocity of 0.1 second or more.

(second active energy ray irradiation step)

When the accumulated light amount of the active energy ray of the active energy ray irradiation devices 31 and 32 is insufficient, it is preferable to further provide the second and subsequent active energy ray irradiation devices 16 to 18, and additionally irradiate the active energy ray to promote the laminated body 4 Hardening of the bonding agent. In addition to the first active energy ray irradiation step, the cumulative light amount in all steps is set to 10 mJ/cm ² or more, and particularly preferably 10 to 5,000 mJ/cm ² . When the cumulative amount of the above-mentioned bonding agent is less than 10 mJ/cm ² , the occurrence of the active species from the initiator is insufficient, and the curing of the bonding agent is insufficient. On the other hand, when the cumulative amount of light exceeds 5000 mJ/cm ² , the irradiation time becomes very long, which is disadvantageous for improving productivity. At this time, depending on the film to be used, the combination of the types of the bonding agents, and the like, the desired amount of light (UVA (320 to 390 nm) or UVB (280 to 320 nm), etc.) is different.

In order to secure the curing of the bonding agent at the end of the polarizing plate (layered body), for example, a method in which "Light Hammer 10" manufactured by FUSION of the electrodeless D bulb is arranged so as to straddle the movement of the film may be employed.

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

(Polarizing plate winding step)

The tension of the wound laminated body (polarizing plate) 4 is from 30 N/cm ² to 150 N/cm ² . It is preferably from 30 N/cm ² to 120 N/cm ² . When it is less than 30 N/cm ² , it is not preferable because the winding difference is caused when moving the long roll. In the case of more than 150 N/cm ² , the winding tension is strong and slack is likely to occur.

Further, the longer the winding length, the more the winding tension is likely to be caused by the same tension (the phenomenon that it is difficult to return to flatness when pulled out), so that the tension can be continuously or stepwise reduced while the polarizing plate is wound onto the winding core. Even in such a method of gradually reducing the tension, the tension at this time is 150 N/cm ² or less.

The length of the polarizing plate taken up by the winding core is not particularly limited, and is preferably 100 m or more and 4000 m or less.

The diameter of the cylindrical core is preferably 6 吋 to 12 直径. The larger the diameter of the core, the better, preferably 11 inches, 12 inches, etc., but it is difficult when it is too large. Move and keep.

Since it is used in a clean room, the material of the cylindrical core is not particularly limited as long as it is difficult to self-drain, and it is possible to ensure that the polarizing plate having a wide width is wound under an appropriate strength, but FRP (optional) can be selected. Glass fiber reinforced plastic).

[Examples]

The invention is illustrated in more detail below by way of examples, but the invention is not limited to the examples.

[Example 1] (production of polarizing film)

A raw material film of polyvinyl alcohol was a long-length 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. The driving nip rolls before and after the processing tank are extended by a peripheral speed difference.

First, the film was kept in a state of tension without loosening the raw material film, and immersed in a swelling tank of pure water at 30 ° C for 80 seconds to sufficiently swell the film. With the swelling of the swelling tank, the ratio of the speed of the inlet to the outlet was 1.2. After the nip rolls were dehydrated, they were immersed in a water dipping tank of pure water at 30 ° C for 160 seconds. In this groove, the stretching ratio in the machine direction was 1.09 times.

Then, 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 while performing uniaxial stretching at a stretching ratio of about 1.5 times. Then, the mixture was immersed at 55.5 ° C for 130 seconds in a boric acid bath containing an aqueous solution of potassium iodide/boric acid/water in a weight ratio of 12/3.7/100, and uniaxially stretched to increase the cumulative stretching ratio of the raw material to 5.7. Then, it was immersed at 40 ° C for 60 seconds in a boric acid bath in which an aqueous solution of potassium iodide/boric acid/water in a weight ratio of 9/2.4/100 was placed.

Further, the washing tank was washed with pure water at 8 ° C for about 16 seconds, and then sequentially passed through a drying furnace at about 60 ° C and a drying furnace at about 85 ° C. The residence time in the drying furnaces was 160 seconds in total. Dry. Thus, a polarizing film having a thickness of 28 μm in which iodine was adsorbed and aligned was obtained.

(production of polarizing plate)

A cellulose acetate-based resin film "KC4FR-1 (manufactured by Konica Minolta Opto Co., Ltd.)" having a thickness of 40 μm as a transparent film and a triacetyl cellulose film "KC8UX2MW" having a thickness of 80 μm (Konica Minolta Opto) was prepared. Company system).

Using the polarizing film and the transparent film prepared as described above, a polarizing plate was produced by the apparatus shown in Fig. 1. First, the epoxy resin of the ultraviolet curable bonding agent is applied to one surface of the cellulose acetate-based resin film "KC4CR-1" to which the retardation characteristics are applied, using a bonding agent coating apparatus (Micro Chamber Doctor: manufactured by Fuji Machinery Co., Ltd.). Resin resin composition "KR series" (made by ADEKA). In addition, an epoxy resin composition "KR series" (manufactured by Adeka Co., Ltd.) of an ultraviolet curable bonding agent was applied to one surface of the above-mentioned triacetone cellulose film "KC8UX2MW" using the same bonding agent coating device. At this time, in the bonding agent coating apparatus, the linear velocity of the polarizing film laminate was 25 m/min, and the thickness of the bonding layer on the cellulose acetate resin film "KC4CR-1" was about 4.0 μm, and triacetyl cellulose. The thickness of the bonding layer on the film and "KC8UX2MW" was about 3.3 μm (a total of about 7.3 μm).

Then, the both sides of the polarizing film are bonded to the cellulose acetate-based resin film "KC4CR-1" and the triacetyl cellulose film "KC8UX2MW" so as to convey the nip between the rubber roller and the metal roller that rotates. And it is bonded by the said epoxy resin composition (ultraviolet hardening type bonding agent) (bonding process).

The polarizing film in which the above two types of transparent films were bonded was applied with a tension of 600 N/m in the longitudinal direction, and moved at a line speed of 25 m/min while being adhered to the cooling roll, and passed through a metal halide of 2 Å. The first active energy ray irradiation step was performed by ultraviolet rays irradiated by a lamp (a power amount of 130 W/cm manufactured by GS-YUASA Co., Ltd.), and passed through a 3-inch electrodeless D bulb (Fusion Co., Ltd. "Light" Hammer 10", the electric power amount of 216 mW/cm) was irradiated with ultraviolet rays, and the second active energy ray irradiation step was performed to prepare a polarizing plate.

The above-mentioned three-electrodeless electrode bulb is a unit in which three units of electrodeless D bulbs arranged in the width direction of the film are arranged in three rows in the longitudinal direction of the film.

In the case of a metal halide lamp, the triacetonitrile cellulose film "KC8UX2MW" bonded to the film was brought into contact with the outer peripheral surface of the cooling roll set at 23 ° C, and the cellulose acetate resin film "KC4CR-1" side was used. Irradiation of ultraviolet light. The rotation speed of the rubber roller that drives the rotation in the bonding step was set to 25.00 m/min, and the rotation speed of the cooling roller was set to 25.23 m/min. That is, when the rotation speed of the rubber roller is 100, the rotation speed of the cooling roller is 100.9.

The cumulative amount of light in the total of the first active energy ray irradiation step and the second active energy ray irradiation step of the present embodiment was 468 mJ/cm ² . The measured light amount is a measurement value obtained by a light irradiation intensity measuring device (UV Power Puck II manufactured by FusionUV Co., Ltd.) in a wavelength region (UVB) having a wavelength of 280 to 320 nm.

(Appearance evaluation)

In the polarizing plate of Example 1 produced as described above, when the appearance of the fluorescent lamp was observed by reflection, no occurrence of wave-plate bending was observed.

[Embodiment 2]

In addition to the transparent film, a cycloolefin resin film "ZEONOR" having a thickness of 60 μm is used. A polarizing plate of Example 2 was produced in the same manner as in Example 1 except that the cellulose acetate-based resin film "KC4CR-1" was used instead of (manufactured by ZEON Co., Ltd., Japan).

(Appearance evaluation)

In the polarizing plate of Example 2 produced as described above, when the appearance was observed in the same manner as in Example 1, the occurrence of wave-like bending was not confirmed.

[Example 3]

In the transparent film, a acetylene resin film "ZEONOR" (manufactured by Nippon Zeon Co., Ltd.) having a thickness of 25 μm was used instead of the cellulose acetate resin film "KC4CR-1", and a triacetonitrile cellulose film "K2UAW" having a thickness of 25 μm was used. Konica Minolta Opto Co., Ltd.) replaced the triacetone cellulose film "KC8UX2MW", and set the rotation speed of the rubber roller that was driven to rotate in the bonding step to 25.00 m/min, and the rotation speed of the cooling roller to 25.08 m/min. That is, when the rotational speed of the rubber roller is 100, the rotational speed of the cooling roller is 100.3. Except for these points, the polarizing plate of Example 3 was produced in the same manner as in Example 1.

(Appearance evaluation)

In the polarizing plate of Example 3 produced as described above, when the appearance was observed in the same manner as in Example 1, the occurrence of wave-like bending was not confirmed.

[Example 4]

In the transparent film, a cycloolefin resin film "ZEONOR" (manufactured by Nippon Zeon Co., Ltd.) having a thickness of 50 μm was used in place of the cellulose acetate resin film "KC4CR-1", and a triacetonitrile cellulose film "TD60UL" having a thickness of 60 μm was used. Fujifilm Co., Ltd.) replaced the triacetone cellulose film "KC8UX2MW" and set the rotation speed of the rubber roller that drives the rotation in the bonding step to 25.00 m/min. However, the rotation speed of the roller was set to 25.28 m/min. That is, when the rotational speed of the rubber roller is 100, the rotational speed of the cooling roller is 101.1. Except for these points, the polarizing plate of Example 4 was produced in the same manner as in Example 1.

(Appearance evaluation)

In the polarizing plate of Example 4 produced as described above, when the appearance was observed in the same manner as in Example 1, the occurrence of wave-plate bending was not confirmed.

[Example 5]

A polarizing plate was produced in the same manner as in Example 1 except that the rotational speed of the rubber roller which was driven to rotate in the bonding step was set to 100, and the rotational speed of the cooling roller was 102.2.

(Appearance evaluation)

In the polarizing plate of Comparative Example 2 produced as described above, the occurrence of the wavy plate bending was not observed when the appearance was observed, but the occurrence of scratches was confirmed.

[Comparative Example 1]

Comparative Example 1 was produced in the same manner as in Example 1 except that the rotational speed of the rubber roller which was driven to rotate in the bonding step was 100, and the rotational speed of the cooling roller was 100, that is, the rotational speed was the same. Polarizer.

(Appearance evaluation)

In the polarizing plate of Comparative Example 1 produced as described above, the occurrence of wave-like bending was confirmed when the appearance was observed.

[Industry use possibility]

The polarizing plate of the present invention can be effectively applied to various display devices including liquid crystal display devices.

1‧‧‧ polarizing film

2, 3‧‧‧ transparent film

4‧‧‧Laminated body (polarizer)

11,12‧‧‧Adhesive coating device

13‧‧‧Rotating roller (cooling roller)

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

19‧‧‧Feed roller

20‧‧‧Winding roller

51, 52‧‧‧ affixing rolls

Claims (3)

A method for producing a polarizing plate is characterized in that a transparent film is bonded to one surface or both surfaces of a polarizing film, and is provided in this order on one side of the transparent film or on one or both sides of the polarizing film. a bonding agent coating step of an active energy ray-curable bonding agent; a laminate in which the transparent film is laminated on one surface or both surfaces of the polarizing film by the bonding agent is sandwiched between a pair of bonding rolls that rotate in a conveying direction And applying a pressure to the laminated body to bond the transparent film to the polarizing film; and when the laminated body is conveyed in a state of being in close contact with a rotating roller that rotates in the conveying direction, the laminated body a first active energy ray irradiation step of irradiating the active energy ray and curing the bonding agent; wherein at least one of the pair of bonding rollers is a rubber roller having a surface formed by rubber and rotationally driven, and the rotating roller The rotation speed is faster than the rotation speed of the aforementioned rubber roller. The method for producing a polarizing plate according to claim 1, wherein the rotating roller is a cooling roller. The method for producing a polarizing plate according to the first or second aspect of the invention, wherein the rotational speed of the rotating roller is 100.1 or more and 102.0 or less.