TWI602685B - Method for manufacturing polarizing plate,and apparatus for manufacturing polarizing plate - Google Patents

Description

Method for manufacturing polarizing plate and manufacturing device for polarizing plate

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

The polarizing film is widely used: in the case of adsorbing and displacing a dichroic dye in a polyvinyl alcohol-based resin film, an iodine-based polarizing film containing iodine as a dichroic dye or a dichroic direct dye as a dichroic property is known. The dye of the pigment is a polarizing film or the like. Such a polarizing film is generally formed by laminating a transparent film such as a triethylenesulfonated cellulose film on one surface or both sides thereof via an adhesive to form a polarizing plate.

A method of laminating a transparent film on one side or both sides of a polarizing film is: after applying an active energy ray-curable resin to a surface of the transparent film in advance, by using a pair of nip rolls with the polarizing film and the transparent film A method in which a wheel (a bonding roller) is pressed to be bonded, and then an active energy ray is irradiated and then hardened (Japanese Patent Laid-Open Publication No. 2004-245925 (Patent Document 1), JP-A-2009-134190 (Patent Literature) 2) Japanese Laid-Open Patent Publication No. 2011-95560 (Patent Document 3)).

When an active energy ray-curable resin is used as an adhesive, the adhesive has a higher viscosity than an adhesive composed of another polyvinyl alcohol-based resin or the like, and therefore it is necessary to apply a laminate composed of a polarizing film and a transparent film. High pressure. At this time, the wrinkles generated when the polarizing film and the transparent film are pressed are hard to escape and disappear, so wrinkled In the folded portion, the bubbles mixed between the two films are hard to escape to the outside, so that the obtained polarizing plate may have a problem such as wrinkles or the like, or bubbles. Moreover, there is also a problem that the process of transportation is deteriorated, and there is a problem that it is easy to cause obstacles in the manufacturing steps.

Prior 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

The present invention has been made to solve the above problems, and aims to provide a A method for producing a polarizing plate that suppresses deformation such as wrinkles or bubbles, and a device for manufacturing a polarizing plate.

The present invention provides a method for producing a polarizing plate which is bonded to a single side or both surfaces of a polarizing film with a transparent film. The manufacturing method includes the following steps: an adhesive coating step, which is attached to the transparent film. An active energy ray-curable adhesive is applied to one surface or both surfaces of the polarizing film; and the bonding step is to laminate the transparent surface on the one surface or both surfaces of the polarizing film via the adhesive The laminated body of the film presses the at least one bonding roller in the direction of the other bonding roller in a state in which the crucible is rotated between the bonding rollers of one pair in the conveying direction, thereby bonding the transparent film and The polarizing film and the active energy ray irradiation step irradiate the laminate with an active energy ray The adhesive is hardened; at least one of the pair of bonding rollers is a metal roller, and a coefficient of static friction between the metal roller and a film contacting the roller is 0.10 to 0.58.

In the bonding step, when the at least one bonding roller is pressed in the direction of the other bonding roller, the pressure applied to the laminate is preferably 0.2 to 3.0 MPa.

Moreover, the present invention provides an apparatus for manufacturing a polarizing plate in which a transparent film is bonded to one surface or both surfaces of a polarizing film, and the manufacturing apparatus includes the following: an adhesive coating device for the aforementioned transparent Applying an active energy ray-curable adhesive to one side of the film or one or both sides of the polarizing film; a pair of bonding rollers for interposing the one or both sides of the polarizing film The laminate in which the transparent film is laminated is transferred while being conveyed to bond the transparent film and the polarizing film, and the active energy ray irradiation device is configured to irradiate the laminate with an active energy ray to cause the aforementioned The agent is hardened; at least one of the pair of bonding rollers is a metal roller, and the coefficient of static friction between the metal roller and the film contacting the roller is 0.10 to 0.58.

According to the present invention, it is possible to provide a polarizing plate which suppresses deformation such as wrinkles or the incorporation of air bubbles. Moreover, the problem of the manufacturing process caused by the deterioration of the conveyance process or the like is also suppressed.

1‧‧‧ polarizing film

2, 3‧‧‧ transparent film

4‧‧‧Layer (Polarizer)

11, 12‧‧‧ adhesive coating device

13‧‧‧Roller (cooling roller)

14, 15, 16, 17, 18‧‧‧Active energy line irradiation device

19‧‧‧Kneading roller for transport

20‧‧‧Winding roller

30‧‧‧Manufacture of equipment

51‧‧‧Finishing roller

52‧‧‧Finishing roller

Fig. 1 is a view showing an embodiment of an apparatus for manufacturing a polarizing plate of the present invention; Side view.

(polarized film)

The polarizing film used in the polarizing plate of the present invention is specifically a one in which a uniaxially stretched polyvinyl alcohol-based resin film is adsorbed and aligned with a dichroic dye. The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. Polyvinyl acetate-based resin In addition to polyvinyl acetate of a homopolymer of polyvinyl acetate, for example, a copolymer of vinyl acetate and other monomers copolymerizable therewith may be mentioned (for example, ethylene-polyvinyl acetate). Ester copolymer) and the like. 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, preferably 90 mol% or more, 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 can be modified, and for example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral or the like modified with an aldehyde can be used.

A film made of such a polyvinyl alcohol-based resin can be used as a raw material film as a polarizing film. The method for forming a film of a polyvinyl alcohol-based resin is not particularly limited, and a film can be formed by a conventionally known and suitable method. The film thickness of the raw material film made of a polyvinyl alcohol-based resin is not particularly limited, but is, for example, about 10 to 150 μm. It is generally supplied in the form of a roll, and has a thickness in the range of 20 to 100 μm, preferably in the range of 30 to 80 μm, and an industrially practical width in the range of 1,500 to 6,000 mm.

Commercially available polyvinyl alcohol-based resin film is, for example, Vinylon VF-PS #7500 (manufactured by Kuraray, raw material thickness: 75 μm), OPL film M-7500 (manufactured by Nippon Synthetic Co., Ltd., thickness: 75 μm), Vinylon VF- PS#6000 (Kuraray, The original material has a thickness of 60 μm, Vinylon VF-PE #6000 (manufactured by Kuraray, raw material thickness: 60 μm), Vinylon VF-PE #5000 (manufactured by Kuraray, raw material thickness: 50 μm), and the like.

The polarizing film is generally produced by a step of dyeing a polyvinyl alcohol-based resin film by a dichroic dye to adsorb a dichroic dye (dyeing step), and a polyvinyl alcohol-based resin film having a dichroic dye adsorbed thereon. a step of treating with an aqueous solution of boric acid (boric acid treatment step), and a step of washing with water after treatment with an aqueous solution of boric acid (water washing treatment step).

Further, in the production of the polarizing film, the polyvinyl alcohol resin film is generally uniaxially stretched. However, the uniaxial stretching may be carried out before the dyeing step, or may be carried out in the dyeing step, or after the dyeing step. Implementation. When uniaxially extending after the dyeing treatment step, the uniaxial extension can be carried out before the boric acid treatment step or in the boric acid treatment step. Uniaxial extension can also be performed at these multiple stages.

The uniaxial extension can be extended to a single axis between rolls having different circumferential speeds, or can be extended to a single axis using a hot roll. Further, the dry stretching may be carried out in the atmosphere, or the wet stretching may be carried out in a state in which the solvent is swollen. The stretching ratio is generally about 3 to 8 times.

The dyeing by the dichroic dye of the polyvinyl alcohol-based resin film in the dyeing treatment step is carried out, 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 can be used. The dichroic dye includes, for example, a dichroic direct dye composed of a disazo compound such as C.I. DIRECT RED 39, and a dichroic direct dye composed of a compound such as trisazo or anthracene azo. Further, the polyvinyl alcohol-based resin film is preferably subjected to a 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 and potassium iodide and dyed is generally used. The content of iodine in the aqueous solution is generally 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is generally 0.5 to 20 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is generally 20 to 40 ° C, and the immersion time (dyeing time) of the aqueous solution is generally 20 to 1800 seconds.

Further, when 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 a water-soluble dichroic dye and dyed is generally used. The content of the dichroic dye in the aqueous solution is generally from 1 × 10 ^-4 to 10 parts by weight, preferably from 1 × 10 ^-3 to 1 part by weight, particularly preferably 1 × 10 ^-3 , per 100 parts by weight of water. To 1 × 10 ^-2 parts by weight. This aqueous solution may 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 from 20 to 80 ° C, and the immersion time (dyeing time) of the aqueous solution is generally from 10 to 1800 seconds.

The boric acid treatment step is carried out by immersing a polyvinyl alcohol-based resin film dyed with a dichroic dye in an aqueous solution containing boric acid. The amount of boric acid in the aqueous boric acid-containing solution is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of the water. When iodine is used as the dichroic dye in the above dyeing treatment step, the boric acid-containing aqueous solution used in the boric acid treatment step preferably contains 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, preferably 5 to 12 parts by weight per 100 parts by weight of the water. The immersion time in the aqueous solution containing boric acid is usually from 60 to 1200 seconds, preferably from 150 to 600 seconds, more preferably from 200 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.

Then, in the water washing treatment step, the polyvinyl alcohol-based resin film after the boric acid treatment described above is immersed in, for example, water, and washed with 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, drying treatment is generally carried out to obtain a polarizing film. The drying treatment is preferably carried out using, for example, 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 generally from 60 to 600 seconds, preferably from 120 to 600 seconds.

In this manner, the polyvinyl alcohol-based resin film is subjected to uniaxial stretching, dyeing of a dichroic dye, 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, a transparent film is bonded to one surface or both surfaces of the above polarizing film. When 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.

Examples of the material constituting the transparent film include a cycloolefin resin, a cellulose acetate resin, polyethylene terephthalate or polyethylene naphthalate, and polyester resin of polybutylene terephthalate. A film material such as a polycarbonate resin, an acrylic resin, or a polypropylene which has been widely used in the field.

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

When a copolymer of a cyclic olefin and a chain olefin or/and an aromatic compound having a vinyl group is used, the chain olefin may, for example, be ethylene or propylene, and the aromatic compound having a vinyl group may, for example, be styrene or α-methyl. Styrene, nucleoalkyl substituted styrene, and the like. In such a copolymer, the monomer unit composed of a cyclic olefin may be 50 mol% or less (preferably 15 to 50 mol%). In particular, when a ternary copolymer of a cyclic olefin and a chain olefin and an aromatic compound having a vinyl group is used, the monomer unit composed of the cyclic olefin may be a small amount as described above. In such a terpolymer, the monomer unit composed of a chain olefin is generally 5 to 80 mol%, and the monomer unit having a vinyl aromatic compound is generally 5 to 80 mol%.

For the cycloolefin resin, an appropriate commercial product such as Topas (manufactured by Ticona Co., Ltd.), Arton (manufactured by JSR Co., Ltd.), ZEONOR (manufactured by Zeon Co., Ltd.), and ZEONEX (manufactured by Zeon, Japan) can be suitably used. Apel (Mitsui Chemical Co., Ltd.), OXIS (manufactured by Okura Industrial Co., Ltd.), etc. When a film is formed by forming a film of such a cycloolefin-based resin, a known method such as a solvent gel casting method or a melt extrusion method can be suitably used. Further, for example, a film made of a cycloolefin-based resin which has been previously formed into a film such as Scena (manufactured by Sekisui Chemical Co., Ltd.), SCA40 (manufactured by Sekisui Chemical Co., Ltd.), or Zeonor film (manufactured by Optes) may be used. Commercial products.

The cycloolefin-based resin film may be uniaxially stretched or biaxially stretched. By extending, an arbitrary phase difference value can be imparted to the cycloolefin-based resin film. The stretching is generally performed while winding up the film roll, and the heating furnace extends in the direction in which the roll is performed (the longitudinal direction of the film), the direction perpendicular to the direction (the width direction of the film), or both directions. 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. Extended magnification Generally 1.1 to 6 times, preferably 1.1 to 3.5 times.

When the cycloolefin-based resin film is wound around the roll, the film tends to adhere to each other and tends to be blocked, and the protective film is generally bonded. Further, since the cycloolefin-based resin film generally has poor surface activity, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame treatment, or saponification treatment is preferably carried out on the surface adjacent to the polarizing film. Among them, it is suitable to be a plasma treatment which can be relatively easily carried out, in particular, atmospheric piezoelectric slurry treatment and corona treatment.

The cellulose acetate resin is a partial or complete 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 triethylenesulfonated cellulose film, a diethylidene cellulose film, a cellulose acetate propionate film, a cellulose acetate butyrate film, or the like can be given. As such a cellulose ester-based resin film, a suitable commercial product such as Fujitac TD 80 (manufactured by Fuji Film Co., Ltd.), Fujitac TD 80UF (manufactured by Fuji Film Co., Ltd.), and Fujitac TD 80UZ (Fuji Film) can be suitably used. )), KC 8UX 2M (Konica Minolta Opto Co., Ltd.), KC8UY (Konica Minolta Opto Co., Ltd.), Fujitac TD 60UL (Fuji Film Co., Ltd.), KC4UYW (Konica Minolta Opto Co., Ltd.) , KC6UAW (Konica Minolta Opto (share) system) and so on.

Further, as the transparent film, a cellulose acetate resin film which imparts phase difference characteristics can be suitably used. Commercially available products of the cellulose acetate-based resin film having such a phase difference characteristic are, for example, WV BZ 438 (manufactured by Fuji Film Co., Ltd.), KC4FR-1 (manufactured by Konica Minolta Opto Co., Ltd.), and KC4CR-1 ( Konica Minolta Opto Co., Ltd., KC4AR-1 (Konica Minolta Opto Co., Ltd.), and the like. Cellulose acetate is also known as ethyl cellulose, also known as cellulose acetate.

These cellulose acetate resin films are easy to absorb water and sometimes polarized. The moisture content of the plate affects the slack at the ends of the polarizing plate. 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, for example, the production line of the clean room or the roll storage warehouse, and the equilibrium moisture content is better, depending on the composition of the laminated film, but for example, 2.0 to 3.5%, more preferably 2.5% to 3.0%. The numerical value of the moisture content of the polarizing plate is a change in weight after drying at 105 ° C for 120 minutes by a dry weight method.

The thickness of the transparent film to be used in the polarizing plate of the present invention is preferably thin, but if it is too thin, the strength is lowered and the workability is poor. Further, if it is too thick, there is a problem that the transparency is lowered or the aging time required after the lamination is increased. Therefore, a suitable thickness of the transparent film is, 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, the polarizing film and/or the transparent film may be subjected to corona treatment, flame treatment, plasma treatment, ultraviolet treatment, primer coating treatment, saponification treatment, etc. deal with.

Further, the surface treatment such as the transparent film, the anti-glare treatment, the anti-reflection treatment, the hard coating treatment, the antistatic treatment, and the antifouling treatment may be carried out singly or in combination of two or more kinds. Further, the transparent film and/or the transparent film surface protective layer may contain a UV absorber such as a benzophenone compound or a benzotriazole compound, or a plasticizer such as a phenyl phosphate compound or a phthalate compound.

Further, the transparent film may have a function as a retardation film, a function as a brightness enhancement film, a function as a reflective film, a function as a semi-transmissive reflection film, a function as a diffusion film, and an optical function as an optical compensation film. . In this case, for example, a retardation film, a brightness enhancement film, a reflective film, a semi-transmissive reflection film, a diffusion film, an optical complement are laminated on the surface of the transparent film. The optical functional film such as a film can have such a function, and can also impart such a function to the transparent film itself. Further, as the diffusion film having the function of the brightness enhancement film, etc., the transparent film can have a plurality of functions.

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

When the metal film is formed by vapor deposition, sputtering, or the like on the transparent film, the function of the reflective film or the semi-transmissive film can be imparted. By coating the resin solution containing fine particles by the above transparent film, ruthenium can impart a function as a diffusion film. In addition, by applying a liquid crystal compound such as a disk-type liquid crystal compound to the transparent film, it is possible to impart a function as an optical compensation film. Further, a compound exhibiting a phase difference may be contained in the transparent film. Further, various optical functional films can be directly bonded to the polarizing film using a suitable adhesive. The commercially available product of the optical functional film is, for example, a brightness enhancement film such as DBEF (made by 3M Company, available from Sumitomo 3M (shares) in Japan), and a viewing angle improving film such as WV Film (Fuji Film Co., Ltd.), Arton Film (JSR), ZEONOR Film (Optes), ESCENA (made by Sekisui Chemical Industry Co., Ltd.), VA-TAC (Konica Minolta Opto Co., Ltd.), Sumicalight (Sumitomo Chemical Co., Ltd.) (such as) phase difference film and the like.

(active energy ray hardening type adhesive)

The polarizing film and the transparent film may be bonded together via an active energy ray-curable adhesive. The active energy ray-curable adhesive is composed of, for example, 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, solventless adhesives, and the like) which have been conventionally used for the production of polarizing plates can be used.

The epoxy resin means a compound having two or more epoxy groups in the molecule. The epoxy resin contained in the curable epoxy resin composition of the adhesive is preferably an epoxy resin which does not contain an aromatic ring in the molecule, for example, from the viewpoints of weather resistance, refractive index, cationic polymerizability and the like (for example, refer to the patent document) 1). Such an epoxy resin may, for example, be a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin or the like.

Hydrogenated epoxy resin method for glycidyl etherification of a nuclear hydrogenated polyhydroxy compound obtained by selective nuclear hydrogenation of a polyhydroxy compound of a raw material of an aromatic epoxy resin in the presence of a catalyst under pressure Come and get. Examples of the aromatic epoxy resin include bisphenol type epoxy resins such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether; and phenol novolak rings; Oxygen resin, cresol novolak epoxy resin, and phenolic varnish type epoxy resin such as hydroxybenzaldehyde phenol novolac epoxy resin; glycidyl ether of tetrahydroxyphenylmethane, glycidyl group of tetrahydroxybenzophenone A polyfunctional epoxy resin such as an ether or an epoxidized polyvinylphenol. Among the hydrogenated epoxy resins, a glycidyl ether of hydrogenated bisphenol A is preferred.

The alicyclic epoxy resin means that there is one or more lipids in the molecule. A ring-bonded epoxy group epoxy resin. The "epoxy group bonded to the alicyclic ring" means the oxygen atom -O- of the bridge of the structure represented by the following formula. In the following formula, m is an integer of 2 to 5.

The group in which one or a plurality of hydrogen atoms in the (CH ₂ ) _m in the above formula is removed is bonded to another compound having a chemical structure, and 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. Among the alicyclic epoxy resins, an epoxy resin having an oxabicyclohexane ring (m=3 in the above formula) or an oxabicycloheptane ring (in the above formula, m=4) It is better to use it in terms of excellent adhesion. Hereinafter, the alicyclic epoxy resin which is preferably used is specifically exemplified, but the compound is not limited thereto.

(a) an epoxycyclohexylmethylepoxycyclohexanecarboxylate represented by the following formula (I);

(wherein R ¹ and R ² each independently 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 each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and n is an integer of 2 to 20).

(c) an epoxycyclohexylmethyl ester of a dicarboxylic acid represented by the following formula (III);

(wherein R ⁵ and R ⁶ each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and p is an integer of 2 to 20).

(d) an 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 is 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 each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms, and r is an integer of 2 to 20).

(f) a diepoxytrisole compound represented by the following formula (VI):

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

(h) Vinylcyclohexene diepoxides 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 each independently represent a hydrogen atom or a linear alkyl group having 1 to 5 carbon atoms).

(j) Dicyclooxy 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 commercially available, or the like, and are preferably used because they are relatively easy to obtain.

(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 formula (I) , compound with R ¹ =R ² =H], (B) 4-methyl-7-oxabicyclo[4.1.0]heptane-3-carboxylic acid and (4-methyl-7-oxa-bicyclic ring) [4.1.0]Hept-3-yl)ester of methanol [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) ( 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 =4 -CH ₃ , compound of p=4], (F) (7-oxabicyclo[4.1.0]heptan-3-yl)methanol and ester of 1,2-ethanediol [in formula (V) Wherein 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, for example, diglycidyl ether of 1,4-butanediol; diglycidyl ether of 1,6-hexanediol; triglycidyl ether of glycerol; three of trimethylolpropane Glycidyl ether; diglycidyl ether of polyethylene glycol; diglycidyl ether of propylene glycol; addition of one or more alkylene oxides to aliphatic polyols such as ethylene glycol, propylene glycol, and glycerin Polyethylene glycidyl ether of a polyether polyol obtained by (ethylene oxide or propylene oxide).

The epoxy resin constituting the adhesive composition of the epoxy resin composition may be used alone or in combination of two or more. The epoxy 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/eq, the flexibility of the composite polarizing plate after curing may be lowered, or the strength may be lowered. On the other hand, when it exceeds 3,000 g/eq, the compatibility with other components contained in the adhesive may be lowered.

In the above-mentioned adhesive, from the viewpoint of reactivity, cationic polymerization is suitably used for the hardening reaction of the epoxy resin. Therefore, the curable epoxy resin composition of the active energy ray-curable adhesive is preferably blended with a cationic polymerization initiator. The cationic polymerization initiator generates a cationic species or a Lewis acid by irradiation with an active energy ray such as visible light, ultraviolet rays, X-rays, or electron beams to initiate polymerization of an epoxy group. Hereinafter, a cationic species or a Lewis acid is produced by irradiation with an active energy ray, and a cationic polymerization initiator which initiates polymerization of an epoxy group is referred to as a "photocationic polymerization initiator".

By using a photocationic polymerization initiator, the method of hardening the adhesive by irradiation of an active energy ray can be hardened at room temperature, and it is necessary to reduce the heat resistance of the polarizing film or the deformation caused by the expansion, and the film can be well adhered. It is very advantageous from the point of view. Further, since the photocationic polymerization initiator acts as a photocatalyst, it 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 iodonium salt or an aromatic sulfonium salt; an iron-heavy olefin complex compound.

Examples of the aromatic diazonium salt include benzenediazo hexafluoroantimonate, benzenediazonium hexafluorophosphate, and benzenediazonium hexafluoroborate. Further, examples of the aromatic iodonium salt include diphenyliodonium (pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, and di(4- Nonylphenyl) iodonium hexafluorophosphate and the like.

Examples of the aromatic sulfonium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium (pentafluorophenyl) borate, and 4,4'- Bis(diphenylthioindenyl)diphenyl sulfide bis(hexafluorophosphate), 4,4'-bis[bis(β-hydroxyethoxy)phenylthioindolyl]diphenyl sulfide (hexafluoroantimonate), 4,4'-bis[bis(β-hydroxyethoxy)phenylthiomethyl]diphenyl sulfide bis(hexafluorophosphate), 7-[di(pair- Tolyl)thiol]-2-isopropylthione hexafluoroantimonate, 7-[two (p-tolyl)thiol]-2-isopropylthioxanthene quinone (pentafluorophenyl)borate, 4-phenylcarbonyl-4'-diphenylthioindolyl-diphenylsulfide Ether hexafluorophosphate, 4-(p-tert-butylphenylcarbonyl)-4'-diphenylsulfanyl-diphenyl sulfide hexafluoroantimonate, 4-(p-tert-butylbenzene Alkylcarbonyl)-4'-bis(p-tolyl)thiol-diphenyl sulfide quinone (pentafluorophenyl) borate.

Further, the iron-heavy olefin complex may, for example, be xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, or Toluene-cyclopentadienyl iron (II)- cis (trifluoromethylsulfonyl) methide or the like.

Commercial products of such photocationic polymerization initiators can be easily obtained, and each of the product names can be, for example, "Kayarad PCI-220" and "Kayarad PCI-620" (above, Nippon Kayaku Co., Ltd.), UVI-6990" (made by Union Carbide), "Adeka Optomer SP-150" and "Adeka Optomer SP-170" (above, ADEKA), "CI-5102", "CIT-1370", "CIT -1682", "CIP-1866S", "CIP-2048S" and "CIP-2064S" (above, Japanese Soda (share) system), "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, MIDORI Chemical Co., Ltd.), "PI-2074" (made by Rhodia Corporation).

The photocationic polymerization initiator may be used singly or in combination of two or more. Among them, the aromatic sulfonium salt system has an ultraviolet absorbing property even in a wavelength region of 300 nm or more, so that a cured product having excellent curability and good mechanical strength or adhesion strength can be obtained, and therefore it is preferably used.

The amount of photocationic polymerization initiator blended relative to epoxy resin 100 The parts by weight are usually from 0.5 to 20 parts by weight, preferably 1 part by weight or more, preferably 15 parts by weight or less. When the blending 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 or the subsequent strength tends to decrease. In addition, when the blending amount of the photocationic polymerization initiator exceeds 20 parts by weight based on 100 parts by weight of the epoxy resin, the ionic substance in the cured product increases, and the hygroscopic property of the cured product becomes high, and the durability can be improved. reduce.

When a photocationic polymerization initiator is used, the curable epoxy resin composition may further contain a photosensitizer as needed. By using a photosensitizer, the reactivity of the cationic polymerization is improved, and the mechanical strength or the strength of the cured product can be improved. The photosensitizer may, for example, be a carbonyl compound, an organic sulfur compound, a persulfide compound, a redox compound, an azo or a diazo compound, a halogen compound or a photoreductive dye.

More specific examples of the photosensitizer include benzoin methyl ether, benzoin isopropyl ether, and benzophenone such as α,α-dimethoxy-α-phenylethyl benzene. Ingredients; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, and 4 a benzophenone derivative such as 4'-bis(diethylamino)benzophenone; a thianeone derivative such as 2-chlorothiazepine or 2-isopropylthioxanone; 2-chloropurine 醌, and 2-methyl onion 醌 醌 醌 derivatives; N-methyl acridone, and N-butyl acridone and other acridone derivatives; others, α, α-II Etethoxyethylbenzene, diphenylethylenedione, anthrone, xanthones, uranium-based compounds, halogen compounds, and the like. The photosensitizer may be used alone or in combination of two or more. The light sensitizer is preferably contained in an amount of 0.1 to 20 parts by weight based on 100 parts by mass of the curable epoxy resin composition.

The epoxy resin contained in the subsequent agent is cured by photocationic polymerization, but it can also be cured by both photocationic polymerization and thermal cationic polymerization. The latter The photocationic polymerization initiator and the thermal cationic polymerization initiator are preferably used together.

The thermal cationic polymerization initiator may, for example, be a benzyl sulfonium salt, a thiophene sulfonium salt, a thiolanium salt, a benzylammonium salt, a pyridinium salt, a hydrazine salt, a carboxylic acid ester or a sulfonic acid. Ester, aminimide, and the like. Such a thermal cationic polymerization initiator can be easily taken from a commercial product, and any of the trade names can be, for example, "Adeka opton CP77" and "Adeka opton CP66" (above, ADEKA AG), "CI -2639" and "CI-2624" (above, manufactured by Japan's Soda Co., Ltd.), "San-aid SI-60L", "San-aid SI-80L" and "San-aid SI-100L" (above, three) New Chemical Industry Co., Ltd.) and so on.

The active energy ray-curable adhesive may further contain a compound which promotes cationic polymerization such as oxetane or a polyhydric alcohol.

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). -oxetanyl)methoxymethyl]benzene, 3-ethyl-3-(phenoxymethyl)oxetane, bis[(3-ethyl-3-oxetan) Alkyl)methyl]ether, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, phenol novolac oxetane, and the like. These oxetane types can be easily taken from commercially available products, and any of them are trade names, and examples thereof include "Aron oxetane OXT-101", "Aron oxetane OXT-121", and "Aron oxetane OXT-". 211", "Aron oxetane OXT-221" and "Aron oxetane OXT-212" (above, East Asia Synthetic Co., Ltd.). These oxetane are generally contained in the curable epoxy resin composition in a ratio of 5 to 95% by weight, preferably 30 to 70% by weight.

When the polyol is not present in an acidic group other than the 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 phenolic hydroxyl group may be mentioned. Polyol compound, Polycarbonate polyols and the like. The molecular weight of these polyols is generally 48 or more, preferably 62 or more, more preferably 100 or more, and still preferably 1,000 or less. These polyols are generally contained in the curable epoxy resin composition in a ratio of 50% by weight or less, preferably 30% by weight or less.

The active energy ray-curable adhesive further blends an ion trapping agent, an antioxidant, a chain shifting agent, a tackifier, a thermoplastic resin, a filler, a flow regulator, a leveling agent, a plasticizer, an antifoaming agent, and the like. . The ion scavenger may, for example, be an inorganic compound such as a powdery lanthanum, a lanthanide, a magnesium, an aluminum, a calcium, a titanium or a mixed system thereof. The antioxidant may, for example, be a hindered phenol antioxidant.

The active energy ray-curable adhesive can be used as a solventless adhesive which does not substantially contain a solvent component. However, since each coating method has an optimum viscosity range, a solvent may be contained in order to adjust the viscosity. The solvent is preferably used in the form of an organic solvent such as a hydrocarbon represented by toluene or an ester represented by ethyl acetate, such as a resin represented by toluene, and an epoxy resin composition. The viscosity of the active energy ray-curable adhesive used in the present invention is, for example, 5 to 1000 mPa. The range around s should be 10 to 200 mPa. s, more preferably 20 to 100 mPa. s.

<<Manufacturing method of polarizing plate>>

Hereinafter, 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 of a polarizing plate of the present invention.

In the manufacturing apparatus 30 of the polarizing plate shown in FIG. 1 , the adhesive application apparatuses 11 and 12 for applying an adhesive to one surface of the transparent films 2 and 3 are sequentially provided along the transport direction; For bonding the transparent films 2, 3 and the polarizing film 1 to obtain a laminate a bonding roller (kneading roller) 51, 52; a roller 13 for adhering the transparent film 2, 3 and the polarizing film 1 to the laminated body 4; and being disposed opposite to the outer circumferential surface of the roller 13 The first active energy ray device 14 and 15 at the position are further provided in the second and subsequent active energy ray irradiation devices 16 to 18 on the downstream side in the transport direction of the first active energy ray device; and the kneading roller 19 for transport.

First, the single layer of the transparent films 2 and 3 which are continuously drawn out from the state of being wound into a roll is coated with the adhesive of the active energy ray-curable adhesive by the adhesive application devices 11 and 12. Cloth step>.

Then, on both sides of the polarizing film 1 which is continuously pulled out in a state of being wound into a roll, the laminate in which the transparent films 2 and 3 coated with the adhesive are laminated via an adhesive is applied to In a state in which the bonding rollers 51 and 52 of one of the transport direction rotations are caught, at least one of the bonding rollers is pressed in the direction of the other bonding roller, and the polarizing film 1 and the transparent films 2 and 3 are bonded. , forming a <bonding step> of the laminate 4.

Then, while the laminate 4 is conveyed while being adhered to the outer peripheral surface of the roller 13, the active energy lines are irradiated from the first active energy ray irradiation devices 14 and 15 toward the outer peripheral surface of the roller 13, and then The agent is polymerized and hardened (active energy ray irradiation step).

Further, the second or 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 adhesive, and may be added or omitted as needed. Finally, the laminate 4 is taken up by the kneading roller 19 for conveyance, and is taken up by the winding roller 20 as a polarizing plate. Hereinafter, each step will be described in detail.

<Binder coating step>

The method of applying the adhesive to the transparent films 2 and 3 is not particularly limited, but for example, a doctor blade, a wire bar, a die coater, and a corner roll coater (comma) can be used. Various coating methods such as coater) and gravure coater. Among them, the applicator coating devices 11, 12 are preferably gravure coaters in consideration of the film coating, the degree of freedom of the sidelines, the correspondence to the width, and the like.

When the adhesive application devices 11 and 12 are applied by an adhesive using a gravure coater having a gravure roll, the thickness (coating thickness) of the applied adhesive is preferably about 0.1 to 10 μm. It is from 0.2 μm to 4 μm. The coating thickness of the subsequent agent is adjusted by the ratio of the ratio of the gravure roll speed to the linear speed of the transparent film. Generally, the draw ratio (speed/line speed of the gravure roll) is adjusted to 0.5 to 10, and the coating thickness of the adhesive can be adjusted to 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 gravure roll is rotated in the opposite direction to the conveying direction of the transparent films 2, 3 so that the speed of the gravure roll is 5 to 1000 m/min. The coating thickness of the adhesive can be adjusted to about 0.1 to 10 μm.

After the agent is prepared, it is generally adjusted to a specific temperature within a range of 15 to 40 ° C ± 5 ° C (for example, a specific temperature of 30 ° C, 30 ° C ± 5 ° C), preferably ± 3 ° C, more preferably Coating at ±1 °C.

<Fitting step>

In this step, the transparent films 2 and 3 coated with the adhesive by the above steps are laminated on the both sides of the polarizing film 1 which is continuously pulled out in a state of being wound into a roll, and the adhesive is applied via the adhesive. In a state in which the laminated body is twisted between the bonding rollers 51 and 52 which are one of the pair in the conveying direction, for example, the bonding roller 51 is pressed in the direction of the bonding roller 52, and the polarizing is applied. The film 1 and the transparent films 2 and 3 form a laminate 4.

In addition, in the first drawing, the adhesive agent is uniformly applied to one surface of the transparent films 2 and 3, and the polarizing film 1 is superposed on the surface of the transparent films 2 and 3 to which the adhesive is applied, and the roller is attached. 51, 52 bonding method, but also uniform on both sides of the polarizing film 1 The adhesive is applied to the surface of the polarizing film 1 to which the adhesive film is applied, and the transparent films 2 and 3 are placed on the surface of the polarizing film 1 and bonded together by the bonding rolls 51 and 52.

The pressure applied to the laminate by pressing is not particularly limited, but when a metal roller and a rubber roller are used, the instantaneous pressure of the two-piece Prescale made of Fuji Film is 0.2 to 3.0 MPa, more preferably 0.5 to 2.5 MPa. In the present invention, the external force applied to the bonding roller is generally applied to the bearing members that are bonded to both ends of the roller.

There may be a difference in the peripheral speed of the bonding roller of one of the pair of bonding roller trains and the bonding roller of the other. For example, it is preferable that the bonding roller (the first bonding roller) of the laminated body 4 to be bonded to the surface side of the liquid crystal panel has a peripheral speed faster than the opposite side of the bonding roller (second bonding roller) The round speed of the wheel). Thereby, the surface to be bonded to the liquid crystal panel can be convex, and the surface on the opposite side can be warped (positive warpage) to the obtained polarizing plate. When the surface to be bonded to the liquid crystal panel is concave, and the surface on the opposite side is convexly warped (reverse warpage) to the obtained polarizing plate, when the polarizing plate is bonded to the liquid crystal cell, it is easily generated in the central portion. Poor conditions such as biting into bubbles. Moreover, in this case, a metal roller is preferably used as the first bonding roller, and a rubber roller is used as the second bonding roller.

Further, when the peripheral speed of the second bonding roller is 1, the ratio of the peripheral speed of the first bonding roller is preferably 1.0050 to 1.0200. When the peripheral speed of the first bonding roller is faster than this range, the amount of warpage of the positive warpage is too large, and when the polarizing plate is attached to the liquid crystal cell, it is liable to cause a bad situation such as biting bubbles at the end, and further When placed in a harsh environment, the positive warpage is further promoted and the end of the polarizing plate is peeled off from the liquid crystal cell.

[fitting roller]

In the present invention, at least one of the pair of bonding rollers 51, 52 is metal The roller has a static friction coefficient between the metal roller and the film of 0.10 to 0.58. Here, the static friction coefficient is a coefficient of static friction between a metal roller and a film (the above-mentioned transparent film or the above-mentioned polarizing film) which is in contact with the metal roller, and indicates that when the objects in contact are stationary with each other, the object is about to start by an external force. When the maximum friction force before the movement is increased to P and the proportional constant is μ, the frictional force F is defined by "F = μ P". The static friction coefficient can be measured by horizontally mounting a known film on a metal roll surface of a measurement target, and applying a force parallel to the contact surface to measure the force at which the film starts to slide on the metal roll. (JIS K7125), it can be measured, for example, using a portable friction meter (trade name: Muse type 94iII) manufactured by Shinto Chemical Co., Ltd.

When the static friction coefficient is more than 0.58, wrinkles generated when the polarizing film and the transparent film are subjected to rolling are hard to escape, and bubbles which are mixed between the two films in such a wrinkle portion are hard to escape to the outside, and thus sometimes obtained The polarizing plate may be deformed such as wrinkles or bubbles. The above static friction coefficient is preferably 0.53 or less, more preferably 0.50 or less. In addition, as the static friction coefficient is smaller, it is preferable to suppress the incorporation of air bubbles. However, if it is too small, the metal roller and the laminate may slide, and the conveyance failure may occur. Therefore, it is preferably 0.10 or more. Further, the metal roller can be applied by coating with a fluororesin or the like, and therefore the static friction coefficient is preferably 0.20 or more.

Further, as shown in Fig. 1, the pressing of the laminate (polarizing film and transparent film) of the bonding rolls 51 and 52 is generally performed by the bearings of the both ends of the bonding roller 51. Hydraulic pressure, air pressure, screws, etc. are pressed. When an active energy ray-curable resin is used as the adhesive, it is necessary to apply a high pressure to the laminate.

The material of the bonding roller may be, for example, metal or rubber. Preferably, one of the pair of bonding rollers is a metal roller, and the other is a rubber roller (at least the outer peripheral surface is a rubber-made bonding roller). When a pair of bonding rollers are made of metal, borrow It is difficult to use continuously because it is easily scratched between the rollers. Further, when the outer peripheral surfaces of the pair of bonding rollers are made of rubber, it is difficult to generate high pressure.

In the conventional bonding roller, the bonding roller on the upper side is generally made of rubber, and the lower bonding roller is made of metal. This is because the lower side of the bonding roller is attached to the drive motor to control the rotation speed. Therefore, when the lower bonding roller is made of metal, the lower bonding roller does not deform when pressed, and it is easy to apply. The peripheral speed of the roller is kept constant. However, in order to facilitate the warpage adjustment of the above-described positive warpage, in the present invention, it is preferable that the bonding roller that presses (upper side) is made of metal, and at least the outer circumference of the other (lower side) bonding roller. The surface is made of rubber.

The base material of the metal roll can be made of various known materials, but it is preferably stainless steel, and more preferably SUS304 (stainless steel containing 18% of Cr and 8% of Ni). The surface of the metal roll is preferably chrome-plated or fluororesin (for example, PTFE (polytetrafluoroethylene) or the like).

The rubber material constituting the rubber roller is not particularly limited, and examples thereof include NBR (nitrile rubber), Titan, urethane, polyfluorene oxide, EPDM (ethylene-propylene-diene rubber), and the like. NBR, Titan, urethane. The hardness of the rubber roller is not particularly limited, but is generally 60 to 100°, preferably 85 to 95°. Further, the hardness of the rubber roller can be measured using a hardness meter according to JIS K6253. For example, a rubber hardness tester "Type-A" manufactured by Asker Co., Ltd., or the like can be used.

The diameter of the pair of bonding rollers 51, 52 is preferably 50 mm or more, less than 300 mm, and more preferably 50 to 250 mm. In this way, by using a relatively small diameter bonding roller, it is difficult to bite air between the polarizing film and the transparent film, and it is easy to avoid a wide adjustment range of the thickness of the adhesive which bites the bubble. A polarizing plate which is difficult to generate bubbles between a polarizing film and a transparent film. Especially, fit When the diameter of the roller is 300 mm or more, air is easily bitten between the polarizing film and the transparent film. Further, when the diameter of the bonding roller is less than 50 mm, there is a case where the strength is not lowered. Further, the bonding roller is formed of at least one pair of rollers, but the diameters of the pair of rollers may be the same or different. The width of the bonding roller is preferably from 300 to 3000 mm.

The material of the pressing roller may be, for example, metal or rubber. The pressing roller provided in contact with the metal bonding roller is preferably made of rubber. Further, the pressing roller provided in contact with the rubber-made bonding roller may be either metal or rubber. When the bonding roller and the pressing roller that are connected to each other are made of metal, it is difficult to continuously use because it is easily scratched between the rollers. In addition, there is no particular problem when the bonding roller and the pressing roller that are in contact with each other are made of rubber.

Further, the arrangement of the bonding roller and the pressing roller is not particularly limited, and may be arranged at an arbitrary angle. That is, the pressing roller train is not limited to the upper and lower sides of the bonding roller, and may be disposed horizontally or at an angle other than the same.

<Active energy ray irradiation step>

The light source used for the polymerization hardening of the adhesive agent by irradiation with the active energy ray is not particularly limited, but is preferably a light source having a light-emitting distribution at 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.

The outer peripheral surface of the roller 13 constitutes a convex curved surface which is mirror-finished, and the laminate 4 is conveyed while being in close contact with the surface thereof, and the adhesive is polymerized and hardened by the active energy ray irradiation devices 14 and 15 in the process. The diameter of the roller 13 is not particularly limited as long as the adhesive is polymerized and hardened, and the laminate 4 is sufficiently adhered. The laminate 4 in which the subsequent agent is in an uncured state is preferably irradiated with an active energy ray such that the integrated light amount during the passage of the roller 13 is 10 mJ/cm ² or more. The roller 13 can be moved or rotationally driven according to the line of the laminate 4, or can be fixed so that the surface can slide the laminate. Further, when the roller 13 is subjected to polymerization hardening by irradiation of an active energy ray, it can function as a cooling roller for dissipating heat generated by the laminated body 4. At this time, the surface temperature of the cooling roll should be set to 20 to 30 °C.

The light irradiation intensity of the active energy ray-curable adhesive is determined depending on the composition of each adhesive, and is not particularly limited, but is preferably 10 to 5000 mW/cm ² . If the light irradiation intensity of the resin composition is less than 10 mW/cm ² , the reaction time is too long, and if it exceeds 5000 mW/cm ² , the heat radiated from the lamp and the heat generated during the polymerization of the composition may be generated. The yellowing of the epoxy resin composition such as the constituent material of the adhesive or the deterioration of the polarizing film. Further, the irradiation intensity is preferably the intensity in the wavelength region in which the activation of the photocationic polymerization initiator is effective, and more preferably the intensity in the wavelength region of 400 nm or less, more preferably the wavelength in the wavelength region of 280 to 320 nm.

The irradiation time of the active energy ray-curable active energy ray-curable adhesive is not particularly limited as long as it is controlled by each hardened composition, but it is preferably set such that the integrated light amount indicated by the product of the irradiation intensity and the irradiation time is 10 mJ/ Above cm ² , it is preferred to be 10 to 5,000 mJ/cm ² . When the integrated light amount of the above-mentioned adhesive is less than 10 mJ/cm ² , the generation of the active species derived from the initiator is insufficient, and the curing of the adhesive becomes insufficient. In addition, when the integrated light amount exceeds 5,000 mJ/cm ² , the irradiation time becomes extremely long, which is disadvantageous for productivity improvement.

In the present invention, the laminate is irradiated with an active energy ray to cure and cure the adhesive, but it may be cured by polymerization by heating.

When the active energy ray is ultraviolet ray, in the step of irradiating the laminate 4 with the active energy ray, it is preferable to apply a tension of 100 to 800 N/m to the longitudinal direction (transport direction) of the laminate 4, and to make the irradiation time 0.1 second or longer. Line speed transfer Laminate 4.

Further, when the integrated light amount of the active energy ray of the active energy ray irradiation devices 14 and 15 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 laminate. 4 of the hardening of the adhesive. The integrated light amount in all the steps is set to 10 mJ/cm ² or more, preferably 10 to 5,000 mJ/cm ² . As such, in the step of irradiating the active energy ray, the irradiation of the active energy ray is preferably carried out in plural times.

In order to reliably perform the curing of the adhesive at the end of the polarizing plate (laminate), for example, a method in which the "Light hammer 10" manufactured by Fusion of the electrodeless bulb is arranged in a horizontal direction with respect to the film travel is exemplified.

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 take-up laminate (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 the roller roll of a long rule is not transferred up to 30 N/cm ^{2 ,} it tends to cause a roll-off offset, which is not preferable. When it is more than 150 N/cm ² , the tension of the roll is strong and it is easy to cause slack.

Further, the longer the winding length is, the more the winding tension is caused by the same tension (the phenomenon that it is difficult to restore the flat state when pulled out), so that the polarizing plate can be wound around the core while the tension is continuously or stepwise. Even in the method of applying a so-called taper to reduce the tension, the tension at this time is 150 N/cm ² or less.

The length of the polarizing plate wound around the core is not particularly limited, but is preferably 100 m or more and 4000 m or less.

The diameter of the cylindrical core is preferably from 6 inches to 12 inches. Core diameter The bigger the better, the better, 11 inches, 12 inches, etc., but if it is too large, it is difficult to transfer or keep.

Since the material of the cylindrical core is used in a clean room, it is difficult to dust itself, and it is not particularly limited as long as it can secure the appropriate strength of the polarizing plate having a wide width, but FRP (glass) can be selected. Fiber reinforced plastic).

(Example)

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited thereto.

<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.

First, in order to prevent the film of the raw material from being slack, the film was kept in a state of tension, and it was immersed in a swelling tank filled with pure water at 30 ° C for 80 seconds to sufficiently swell the film. The ratio of the roller speeds of the inlet and the outlet accompanying the swelling of the swelling tank was 1.2. After the water was removed by the kneading roller, it was immersed in a water immersion tank containing pure water at 30 ° C for 160 seconds. The stretching ratio of the machine direction in this groove was 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 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 while performing uniaxial stretching until the integral stretching ratio derived from the raw material became 5.7. Up to the end. Thereafter, it was immersed in a boric acid tank containing an aqueous solution of potassium iodide/boric acid/water in a weight ratio of 9/2.4/100 at 40 ° C. second.

Further, the washing tank was washed with pure water of 8 ° C for about 16 seconds, and then passed through a drying furnace of about 60 ° C and a drying furnace of about 85 ° C in order to make the residence time in the drying furnace a total of 160 seconds. And dry. In this way, a polarizing film having a thickness of 28 μm in which iodine was adsorbed and aligned was obtained.

(production of polarizing plate)

In the transparent film, a cellulose acetate-based resin film "KC4CR-1 (manufactured by Konica Minolta Opto Co., Ltd.)" having a phase difference characteristic of 40 μm and a triethoxymethyl cellulose film "KC8UX2MW" having a thickness of 80 μm were prepared. (Konica Minolta Co., Ltd.), on the other side, an epoxy resin composition "KR-70T" (manufactured by Adeka Co., Ltd.) of an ultraviolet curable adhesive was applied by using an adhesive application device. At this time, the linear velocity of the polarizing film laminate of the adhesive application device was 25 m/min, and the adhesive coating apparatus used a gravure coater to move the gravure roller of the coating portion toward the laminating material. Rotating in the opposite direction, the thickness of the adhesive layer was 2.5 μm.

Next, on the both sides of the polarizing film, the cellulose acetate-based resin film having the phase difference characteristic and the triethylene fluorinated cellulose film are interposed between the epoxy resin composition and a pair of 240 mm in diameter. The kneading rolls (bonding rolls) were bonded together and pressed at a pressing pressure of 1.3 MPa (measured by a two-piece Proscale manufactured by Fuji Film). Further, one of the pair of bonding rolls (the side of the cellulose acetate resin film to which the phase difference characteristic is applied) is a metal roll, and the other (triethylenesulfonated cellulose film side) is a rubber roll. wheel. The metal roller is a hard chrome plated surface of SUS, and is ground to have a surface roughness of 0.40 s. The rubber roller is made of NBR. Further, the metal roller is disposed on the upper side, and the rubber roller is disposed on the lower side.

The metal roller is connected to the roller to give a phase difference The static friction coefficient between the cellulose acetate-based resin films of the characteristics was measured by a portable friction meter (trade name: Muse type 94i II) manufactured by Shinto Chemical Co., Ltd., and was 0.48.

The polarizing film to which the above two kinds of transparent films were bonded was applied with a tension of 600 N/m in the longitudinal direction, and simultaneously transferred at a linear velocity of 25 m/min, and the total integrated light amount was irradiated (light irradiation intensity in a wavelength region of a wavelength of 280 to 320 nm) The integral amount is ultraviolet light (UVB) of about 250 mJ/cm ² (measuring device: measured value of UV Power Puck II manufactured by Fusion UV Co., Ltd.).

In the obtained polarizing plate, no deformation was observed by visual observation, and deformation or bubbles such as wrinkles were not observed visually between the polarizing film and the cellulose acetate resin film to which the phase difference property was imparted.

<Example 2>

In the same manner as in the first embodiment, except for the transparent film, a cycloolefin-based resin film "Zeonor" (manufactured by Zeon Co., Ltd.) having a thickness of 50 μm was used, and the thickness of the surface of the metal roll was 2.45 s. Make a polarizer. The static friction coefficient between the metal roller and the cycloolefin resin film that is in contact with the roller is measured using a portable friction meter (trade name: Muse type 94i II) manufactured by Shinto Chemical Co., Ltd. 0.28. In the obtained polarizing plate, no deformation was observed by visual observation, and deformation or bubbles such as wrinkles were not observed visually between the polarizing film and the cycloolefin-based resin film.

<Example 3>

In the case of the transparent film, a cycloolefin resin film "Zeonor" (manufactured by Zeon Co., Ltd.) having a thickness of 50 μm was used, and the surface of the metal roller was 0.80 s, and the metal coated with the fluororesin was used. A polarizing plate was produced in the same manner as in Example 1 except for the roll. Further, the surface roughness of the metal roller coated with the fluororesin was 0.80 s. a metal roller and a cycloolefin resin film connected to the roller The coefficient of static friction between the two was measured using a portable tribometer (trade name: Muse type 94i II) manufactured by Shinto Chemical Co., Ltd., and was 0.12. In the obtained polarizing plate, no deformation was observed by visual observation, and deformation or bubbles such as wrinkles were not observed visually between the polarizing film and the cycloolefin-based resin film.

<Comparative Example 1>

A polarizing plate was produced in the same manner as in Example 1 except that a cycloolefin resin film "Zeonor" (manufactured by Zeon Co., Ltd.) having a thickness of 50 μm was used for the transparent film. The static friction coefficient between the metal roller and the cycloolefin resin film that is in contact with the roller is measured using a portable friction meter (trade name: Muse type 94i II) manufactured by Shinto Chemical Co., Ltd. 0.62. In the obtained polarizing plate, deformation or bubbles such as wrinkles were visually observed between the polarizing film and the cycloolefin resin film.

(industrial availability)

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‧‧‧Layer (Polarizer)

11, 12‧‧‧ adhesive coating device

13‧‧‧Roller (cooling roller)

14, 15, 16, 17, 18‧‧‧Active energy line irradiation device

19‧‧‧Kneading roller for transport

20‧‧‧Winding roller

30‧‧‧Manufacture of equipment

51‧‧‧Finishing roller

52‧‧‧Finishing roller

Claims (5)

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 manufacturing method includes the following steps: an adhesive coating step of one side of the transparent film or the polarized light An active energy ray-curable adhesive is applied to one side or both sides of the film; and the bonding step is a laminate in which the transparent film is laminated on one surface or both surfaces of the polarizing film via the adhesive. a state in which the at least one bonding roller is pressed against the other bonding roller in a state in which the pair of the bonding rollers are rotated in the conveying direction, thereby bonding the transparent film and the polarizing film; And an active energy ray irradiation step of curing the adhesive by irradiating the laminate with an active energy ray; wherein one of the pair of bonding rollers is a metal roller and the other is at least an outer peripheral surface a rubber roller made of rubber; the circumferential speed of the metal roller is faster than the circumferential speed of the rubber roller; and the static friction coefficient between the metal roller and the film connected to the roller is 0.10 To 0.58. The manufacturing method of claim 1, wherein in the bonding step, when the at least one bonding roller is pressed in the direction of the other bonding roller, the pressure applied to the laminate is 0.2 to 3.0. MPa. The manufacturing method according to claim 1 or 2, wherein the metal roller system is located on the upper side, and the rubber roller system is located on the lower side. A manufacturing apparatus of a polarizing plate which is bonded to a single surface or a double-sided surface of a polarizing film, wherein the manufacturing apparatus includes an adhesive coating device for one side of the transparent film or the partial An active energy ray-curable adhesive is applied to one side or both sides of the light film; and a pair of bonding rolls are used to laminate the one or both sides of the polarizing film via the adhesive The laminate of the transparent film is pressed while being conveyed to bond the transparent film and the polarizing film, and the active energy ray irradiation device is configured to irradiate the laminate with an active energy ray to cure the adhesive; One of the pair of bonding rollers is a metal roller, and the other is a rubber roller having at least an outer peripheral surface made of rubber; the circumferential speed of the metal roller is faster than that of the rubber roller The circumferential speed; the static friction coefficient between the aforementioned metal roller and the film connected to the roller is 0.10 to 0.58. The apparatus for manufacturing a polarizing plate according to claim 4, wherein the metal roller system is located on the upper side, and the rubber roller system is located on the lower side.