KR101981078B1 - Photocurable adhesive composition, polarizing plate and a process of producing the same, optical member, and liquid crystal display device - Google Patents

Abstract

(B) 탄소수 2∼15개를 갖는 폴리올(단, 알킬렌옥사이드 단위의 반복수 3 이상의 폴리에테르폴리올을 제외함)의 폴리(메타)아크릴레이트, (C) 광양이온 중합 개시제, 및 (D) 하기 식(2)으로 나타내는 옥세탄 화합물을 함유하고,

상기 (A)∼(D)성분의 함유 비율이 조성물 중에 (A)성분:20∼80중량%, (B)성분:10∼55중량%, (C)성분:0.5∼10중량%, (D)성분:1∼25중량%인 것을 특징으로 한다.The photo-curing adhesive composition of the present invention can be selected from the group consisting of a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin resin to a polarizer formed of a polyvinyl alcohol resin film in which a monoaxially stretched dye is adsorbed and oriented (A) an epoxy compound having at least two alicyclic epoxy groups represented by the following formula (1) in the molecule, and

(B) a poly (meth) acrylate of a polyol having 2 to 15 carbon atoms (provided that a polyether polyol having 3 or more repeating units of an alkylene oxide unit is excluded), (C) a cationic polymerization initiator, and (D) And an oxetane compound represented by the following formula (2)

(A): 20 to 80% by weight, (B): 10 to 55% by weight, (C): 0.5 to 10% by weight, (D) ) Component: 1 to 25% by weight.

Description

TECHNICAL FIELD The present invention relates to a photo-curing adhesive composition, a polarizing plate and a method for producing the same, an optical member, and a liquid crystal display device using the photo-

The present invention relates to a photo-curable adhesive composition used for bonding a polarizer and a protective film in a polarizing plate, a polarizing plate in which a protective film is bonded to a polarizer using the adhesive composition, and a method for producing the polarizing plate. The present invention also relates to an optical member and a liquid crystal display device using this polarizing plate.

The polarizing plate is useful as one of the optical components constituting the liquid crystal display device. The polarizing plate is usually used by being attached to a liquid crystal display device in a state where a protective film is laminated on both surfaces of a polarizer. It is also known to provide a protective film on only one side of a polarizer. In most cases, however, a layer having a different optical function is bonded to the other side as a protective film, not merely as a protective film. Further, as a method of producing a polarizer, a method of treating a uniaxially stretched polyvinyl alcohol resin film dyed with a dichroic dye and subjecting it to boric acid treatment, followed by washing with water is well known.

Normally, the protective film is bonded to the polarizer immediately after the above-described water washing and drying. This is because the polarizer after drying has a weak physical strength, and once it is wound, the polarizer is ruptured in the processing direction. Therefore, after drying, the polarizer is conventionally coated with an aqueous adhesive immediately, and then the protective film is bonded on both sides simultaneously with the adhesive. Conventionally, a triacetylcellulose film having a thickness of 30 to 120 mu m is used as a protective film.

A polyvinyl alcohol-based adhesive is often used to adhere a protective film made of a polarizer and a protective film, particularly a triacetylcellulose film. However, there is an attempt to use a urethane-based adhesive in place of this. For example, Japanese Unexamined Patent Application Publication No. 7-120617 (Patent Document 1) discloses that a urethane prepolymer is used as an adhesive and a polarizer having a high water content is bonded to a cellulose acetate-based protective film, for example, a triacetylcellulose film .

On the other hand, since triacetyl cellulose has high moisture permeability, there is a problem that the polarizing plate bonded with the resin film as a protective film causes deterioration under the condition of, for example, a temperature of 70 DEG C and a relative humidity of 90%. Thus, a method for solving such a problem by using a resin film having a lower moisture permeability than triacetylcellulose film as a protective film has been proposed. For example, it has been known to use an amorphous polyolefin resin as a protective film. Specifically, it is described in JP-A-6-51117 (Patent Document 2) that a thermoplastic saturated norbornene resin sheet is laminated on at least one surface of a polarizer as a protective film.

When a protective film having such a low moisture permeability is bonded to a conventional device, an adhesive using water as a main solvent, for example, a so-called wetting method in which a protective film is bonded to a polyvinyl alcohol polarizer using a polyvinyl alcohol aqueous solution, There is a problem that sufficient adhesion strength is not obtained or appearance becomes poor in lamination. This is because the film having a low moisture permeability is generally hydrophobic compared with the triacetyl cellulose film, but the water as a solvent can not be sufficiently dried because of low moisture permeability.

Japanese Unexamined Patent Application Publication No. 2000-321432 (Patent Document 3) proposes bonding of a protective film made of a polyvinyl alcohol polarizer and a thermoplastic saturated norbornene resin with a polyurethane adhesive. However, the polyurethane-based adhesive has a problem that a long time is required for curing, and the adhesive strength is not necessarily sufficient.

On the other hand, it is also known to bond different kinds of protective films to both sides of a polarizer. For example, Japanese Patent Application Laid-Open No. 2002-174729 (Patent Document 4) discloses a polarizer comprising a polarizer made of a polyvinyl alcohol- It has been proposed to bond a protective film made of a polyolefin resin to the other surface and to bond a protective film made of triacetyl cellulose different from that of the amorphous polyolefin resin to the other surface. Japanese Patent Application Laid-Open No. 2005-208456 Patent Document 5) discloses a method in which a cycloolefin resin film is laminated on one side of a polarizing film made of a polyvinyl alcohol resin through an aqueous first adhesive agent containing a specific urethane resin and a second adhesive agent A second aqueous adhesive agent, for example, an aqueous solution of a polyvinyl alcohol resin, It has been proposed to laminate.

In Patent Document 4, what is called an amorphous polyolefin-based resin and also referred to as a cycloolefin-based resin in the Patent Document 5 is norbornene or a derivative thereof, a polycyclic cycloolefin such as dimethano-octahydronaphthalene When a double bond is left, such as a ring-opening polymer, the thermoplastic resin is preferably hydrogenated.

Japanese Unexamined Patent Publication (Kokai) No. 2004-245925 discloses an adhesive mainly comprising an epoxy resin not containing an aromatic ring. The adhesive is irradiated with an active energy ray to be cationically polymerized to form a polarizer and a protective film There has been proposed a method of bonding. The epoxy-based adhesive disclosed here is particularly effective for bonding various transparent resin films including an amorphous polyolefin-based resin and a cellulose-based resin to a polarizer, but particularly when an acrylic resin is used as a protective film, It became clear.

Therefore, the present inventors have found that when a resin film having low moisture permeability selected from an acrylic resin, a polyester resin, a polycarbonate resin and an amorphous polyolefin resin is used as a protective film for a polarizer, An adhesive was developed. As a result, it has been found that a composition comprising a glycidyl ether type epoxy resin having an aromatic ring and an oxetane compound gives a good adhesive force, and particularly a composition containing 5 to 25% by weight of a (meth) acrylate monomer having an alicyclic skeleton (See Patent Document 7). However, although the production process itself ends with a short-time process of light irradiation, the adhesive has a problem in that it does not exhibit sufficient adhesion force after a certain period of time after the film is wound. For this reason, there has been a problem that handling of the film after light irradiation in the production process is difficult.

Japanese Patent Laid-Open No. 7-120617 Japanese Patent Laid-Open No. 6-51117 Japanese Patent Application Laid-Open No. 2000-321432 Japanese Patent Application Laid-Open No. 2002-174729 Japanese Patent Application Laid-Open No. 2005-208456 Japanese Patent Application Laid-Open No. 2004-245925 Japanese Patent Application Laid-Open No. 2010-209126

In order to solve the problem of bonding the polyvinyl alcohol polarizer and the protective film having low moisture permeability to each other by wet lamination, it is considered to make the drying time longer by increasing the length of the drying furnace after the bonding. However, There arises a problem that discoloration due to heat deterioration of the photoreceptor is liable to occur. Therefore, it is considered that the drying temperature is lowered so as not to cause thermal degradation of the polarizer. However, in this case, it is necessary to make the drying furnace length longer in order to dry sufficiently. When the protective film of different kind is bonded to both surfaces of the polarizer, since the shrinkage ratio of the protective film due to heat is different, the shrinkage amount of the protective film on both sides is different from that of the polarizer, and the polarizer is curled when it returns to room temperature after drying There is a problem that it is easy to do.

In order to solve such a problem, it is considered to adopt a bonding method by dry lamination. However, from the problem that the physical strength of the polarizer is weak because the adhesive having the dry lamination suitability is very high, the method of adhering the polarizer to the protective film is limited to a method of applying an adhesive to the protective film and then bonding it to the polarizer. In this method, foreign matter can not be concealed in the case where foreign matter adheres to the surface of the adhesive before bonding, and bubbles are generated between the adhesive layer and the polarizer starting from the foreign object as a starting point after bonding.

Therefore, it is an object of the present invention to provide a resin film which is low in moisture permeability and which is selected from a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin resin, To provide a photo-curing adhesive which has a good final adhesion and which does not cause problems such as poor appearance after an endurance test and which has a low viscosity and to provide a polarizer in which a protective film is bonded to a polarizer using the adhesive. It is still another object of the present invention to provide an optical member capable of forming a liquid crystal display device having excellent reliability by using this polarizing plate and to apply it to a liquid crystal display device.

That is, according to the present invention, a polarizer made of a polyvinyl alcohol-based resin film which is uniaxially stretched and in which a dichroic dye is adsorbed and aligned is provided with a resin selected from the group consisting of polyester resin, polycarbonate resin, acrylic resin and amorphous polyolefin resin As an adhesive composition for adhering a protective film made of a transparent resin film,

(A) an epoxy compound having at least two alicyclic epoxy groups represented by the following formula (1) in the molecule,

(B) a poly (meth) acrylate of a polyol having 2 to 15 carbon atoms (provided that a polyether polyol having 3 or more repeating units of an alkylene oxide unit is excluded), (C) a cationic polymerization initiator, and (D) And an oxetane compound represented by the formula (2)

The content ratio of the components (A) to (D)

Component (A): 20 to 80 wt%

Component (B): 10 to 55 wt%

(C): 0.5 to 10 wt%

Component (D): 1 to 25 wt%

Wherein the photocurable adhesive composition is a photocurable adhesive composition.

In the composition of the present invention, as the component (A), an epoxy compound represented by the following formula (4) is preferable.

As the component (B), a di (meth) acrylate of a diol having 5 to 10 carbon atoms (except polyether diol having 3 or more repeating number of alkylene oxide units is excluded) is more preferable. As the (meth) acrylate, acrylate is more preferable.

The preferable content of the component (A) and the component (B) is 35 to 75% by weight and 10 to 35% by weight, respectively, in the composition.

The composition of the present invention preferably contains, as the component (E), 1 to 18% by weight of the oxetane compound represented by the following formula (3) in the composition.

The radical polymerizable component such as the component (B) contained in these photo-curable adhesive compositions can be cured by radicals generated when the component (C) is decomposed into light. However, in order to obtain a sufficient reaction rate with a small irradiation dose, Is contained in the composition in a proportion of 10% by weight or less.

Further, in order to obtain a coating surface excellent in smoothness, these photo-curing adhesive compositions preferably contain a leveling agent (G) in an amount of 001 to 0.5 wt% in the composition.

Further, according to the present invention, a polarizer made of a polyvinyl alcohol-based resin film which is uniaxially stretched and in which a dichroic dye is adsorbed and oriented is selected from a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin- And a protective film made of a transparent resin film are bonded to each other, wherein the adhesive is formed of any one of the photocurable adhesive compositions described above.

The polarizing plate includes an adhesive applying step of applying any one of the above-mentioned photo-curable adhesive compositions to at least one of the bonding surfaces of the polarizer and the protective film, a bonding step of bonding the polarizer and the protective film to each other through the adhesive layer obtained, And a curing step of curing the photo-curable adhesive composition interposed as an adhesive layer between the photo-curable adhesive composition and the photo-curable adhesive composition. Specifically, there is a method of applying an uncured photocurable adhesive composition to a polarizer, bonding a protective film to the adhesive composition coating surface, and then curing the adhesive composition to form an adhesive layer; a method of forming an uncured adhesive A method in which a polarizer is bonded to the adhesive composition coating surface after the composition is applied and then the adhesive composition is cured to form an adhesive layer; a method of softening the uncured, photo-curable adhesive composition between the polarizer and the protective film, A method in which an adhesive composition is uniformly stretched and spread by sandwiching the adhesive with a roller or the like, and then the adhesive composition is cured to form an adhesive layer.

According to the present invention, there is also provided an optical member in which at least one optical layer exhibiting an optical function different from that of the above-mentioned polarizing plate is laminated. At least one of the other optical layers in this case is preferably a retarder. And the optical member is disposed on one side or both sides of the liquid crystal cell.

(Effects of the Invention)

The photo-curable adhesive composition of the present invention exhibits an adhesive force quickly after light irradiation even when a protective film is formed of a resin film having low moisture permeability selected from a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin resin, The final adhesive force after the lapse of time is also good, and the problem such as defective appearance is not caused even after the endurance test. This adhesive composition is particularly useful when the protective film is composed of an acrylic resin. Further, since the adhesive composition of the present invention has a very low viscosity, it is easy to apply it thinly and bond it without defects. A polarizing plate obtained by bonding a polarizer and a protective film through this adhesive composition can be produced with good productivity since the adhesive composition is not only cured by a short time process of light irradiation but also has an adhesive strength of a constant intensity even immediately after light irradiation. Further, an optical member in which this polarizing plate is combined with another optical layer can form a liquid crystal display device having excellent reliability.

Hereinafter, the present invention will be described in detail. In the present invention, a photo-curable adhesive composition having a specific composition is used in adhering a protective film made of a transparent resin film to a polarizer made of a polyvinyl alcohol-based resin film which is uniaxially stretched and adsorbed dichroic dye. Thus, the polarizer is bonded to the protective film through the photo-curable adhesive composition. The polarizing plate may be laminated with an optical layer having another optical function to form an optical member. Further, the optical member can be disposed on at least one side of the liquid crystal cell to make a liquid crystal display device. Hereinafter, the photo-curable adhesive composition, the polarizing plate, the method for producing the polarizing plate, the optical member, and the liquid crystal display will be described in order.

[Photo-curable adhesive composition]

In the present invention, a photocurable adhesive composition having a specific composition is used for bonding the polarizer and the protective film. Hereinafter, this photo-curable adhesive composition may be simply referred to as "photo-curable adhesive" or "composition". The photo-curable adhesive of the present invention contains the following four components (A), (B), (C) and (D) as essential components.

(A) an epoxy compound having at least two alicyclic epoxy groups represented by the following formula (1) in the molecule,

(B) a poly (meth) acrylate of a polyol having 2 to 15 carbon atoms (provided that the polyether polyol having 3 or more repeating number of alkylene oxide units is excluded)

(C) a photocationic polymerization initiator, and

(D) an oxetane compound represented by the following formula (2).

In this specification, the epoxy compound (A) is also referred to as the "component (A)" or the "epoxy compound (A)" and the poly (meth) (D) is also referred to as "(D) acrylate (B)", and the cation polymerization initiator (C) is also referred to as " ) Component " or " oxetane compound (D) ".

The content of the components (A) to (D) in the composition is from 20 to 80% by weight, the component (B) is from 10 to 55% by weight, the component (C) (D) is 1 to 25% by weight.

The photo-curable adhesive may optionally contain an oxetane compound represented by the following formula (3) as the component (E), and it is preferable that the content of the photo-curable adhesive is in the range of 1 to 18% by weight. (F), a photo-radical polymerization initiator, and a leveling agent as the component (G).

In the present specification, the oxetane compound (E) is also referred to as "component (E)" or "oxetane compound (E)" and the photo radical polymerization initiator of (F) Initiator (F) ", and the leveling agent of (G) is also referred to as" (G) component "or" leveling agent (G) ".

≪ Epoxy Compound (A) >

In the photocurable adhesive of the present invention, the epoxy compound as the component (A) is an epoxy compound having at least two alicyclic epoxy groups represented by the following formula (1) in the molecule, and various generally known curable epoxy compounds can be used .

Specific examples of the component (A) include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexylmethyl- Caprolactone-modified products of 3,4-epoxycyclohexanecarboxylate, esterified or caprolactone-modified products of a polyvalent carboxylic acid and 3,4-epoxycyclohexylmethyl alcohol, alicyclic epoxy compounds represented by the formula (1) And the like.

As the component (A), an epoxy compound represented by the following formula (4) is preferable because of its low viscosity, curability, adhesive strength and durability.

The epoxy compound of component (A) may be used alone or in combination of two or more.

The content of the epoxy compound in the component (A) is in the range of 20 to 80% by weight based on the entire composition. By setting this range, it is possible to improve the adhesive strength immediately after the light irradiation, the final adhesive force, and the durability. The content of the component (A) in the range of 35 to 75% by weight can improve the adhesive strength.

≪ Poly (meth) acrylate (B) >

In the photocurable adhesive of the present invention, the poly (meth) acrylate to be the component (B) is a poly (meth) acrylate of a polyol having 2 to 15 carbon atoms (provided that the polyether polyol having three or more repeating units of the alkylene oxide is excluded) (Meth) acrylate.

(Meth) acrylate in which the number of (meth) acryloyl groups in the molecule is 1 tends to be insufficient in durability such as resistance to cold and heat cycles. In addition, even in the case of a polyol having 2 to 15 carbon atoms, the (meth) acrylate obtained from the polyether polyol having 3 or more repeating number of alkylene oxide units tends to lack durability such as resistance to cold and heat cycles.

By using the component (B), the viscosity of the composition is reduced, and the adhesion to the polarizer and durability are excellent. As the component (B), a di (meth) acrylate of a diol having 5 to 10 carbon atoms (except for the polyether diol having 3 or more repeating number of alkylene oxide units) has a low viscosity, . Further, as the (meth) acrylate, acrylate is preferable from the viewpoint of curability.

Specific examples of the component (B) include neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 3-methyl-1,5-pentanediol di (meth) acrylate, (Meth) acrylate, 2-butyl-2-ethyl-1,3-propanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, ethylene glycol di Acrylate, propylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, dipropyleneglycol di (meth) acrylate, tricyclodecane dimethiol di Acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri or tetra (meth) acrylate, dipentaerythritol penta or hexa Di (meta) of hydrogenated bisphenol A ) Acrylate, and the like.

The component (B) may have an ester skeleton or an isocyanurate skeleton. Specific examples of the compound having an ester skeleton include neopentyl glycol, an esterification reaction product of hydroxypivalic acid and (meth) acrylic acid, and examples of the compound having an isocyanurate skeleton include isocyanuric acid alkylene oxide adduct Di- or tri (meth) acrylates of water, and the like.

Of these, 1,6-hexanediol di (meth) acrylate and the esterification reaction product of neopentyl glycol, hydroxypivalic acid and (meth) acrylic acid are excellent in low viscosity, adhesion and durability, Particularly preferred.

The content of the component (B) is in the range of 10 to 55% by weight based on the whole composition. By setting this ratio, the adhesive force immediately after the light irradiation, the final adhesive force, and the durability can be improved. The content of the component (B) in the range of 10 to 35% by weight can improve the adhesive strength.

≪ Gwangyang Ion Polymerization Initiator (C) >

The photo-curable adhesive of the present invention contains the epoxy compound (A), the oxetane compound (D) and the oxetane compound (E) described later as necessary as curing components, and these are all cured by cationic polymerization , A photocationic polymerization initiator is incorporated as component (C). This photocationic polymerization initiator generates a cationic species or Lewis acid by irradiation of an active energy ray such as visible light, ultraviolet ray, X-ray or electron ray to initiate polymerization reaction of an epoxy group or an oxetanyl group.

(C), it is possible to cure at room temperature, and it is possible to reduce the need to consider deformation due to heat resistance and expansion or contraction of the polarizer, thereby satisfactorily bonding the protective film. Further, since the photocationic polymerization initiator acts catalytically by irradiation of an active energy ray, it is excellent in storage stability and workability even when mixed with the epoxy compound (A) and the oxetane compound (D). Examples of the compound capable of generating a cationic species or Lewis acid by irradiation with an active energy ray include an aromatic diazonium salt, an onium salt such as an aromatic iodonium salt and an aromatic sulfonium salt, and an iron-allene complex.

Examples of the aromatic diazonium salt include the following compounds.

Benzene diazonium hexafluoroantimonate, benzene diazonium hexafluoroantimonate,

Benzene diazonium hexafluorophosphate,

Benzene diazonium hexafluoroborate and the like.

As the aromatic iodonium salt, for example, the following compounds can be mentioned.

Diphenyl iodonium tetrakis (pentafluorophenyl) borate,

Diphenyl iodonium hexafluorophosphate,

Diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluoroantimonate,

Di (4-nonylphenyl) iodonium hexafluorophosphate, and the like.

Examples of the aromatic sulfonium salt include the following compounds.

Triphenylsulfonium hexafluorophosphate,

Triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluoroantimonate,

Triphenylsulfonium tetrakis (pentafluorophenyl) borate,

4,4'-bis (diphenylsulfono) diphenylsulfide bis hexafluorophosphate,

4,4'-bis [di (beta -hydroxyethoxy) phenylsulfonio] diphenylsulfide bis hexafluoroantimonate,

4,4'-bis [di (? -Hydroxyethoxy) phenylsulfonio] diphenylsulfide bis hexafluorophosphate,

7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate,

7- (di (p-toluyl) sulfonio] -2-isopropylthioxanthontetrakis (pentafluorophenyl) borate,

4-phenylcarbonyl-4'-diphenylsulfone-diphenylsulfide hexafluorophosphate,

4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate,

4- (p-tert-butylphenylcarbonyl) -4'-di (D-tolyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate and the like.

As the iron-allene complex, for example, the following compounds can be mentioned.

Xylene-cyclopentadienyl iron (II) hexafluoroantimonate,

Cumene-cyclopentadienyl iron (II) hexafluorophosphate,

Xylene-cyclopentadienyl iron (II) -tris (trifluoromethylsulfonyl) methanide, and the like.

Each of these photo cationic polymerization initiators may be used singly or in combination of two or more. Among them, aromatic sulfonium salts are preferably used because they have excellent ultraviolet ray absorbing property in a wavelength range of 300 nm or more and are excellent in curability and can give a cured product having good mechanical strength and adhesive strength.

(C) are commercially available products. For example, "KayaRad PCI-220", "KayaRad PCI-620" (manufactured by Nippon Kayaku Co., Ltd.) CIT-1370 "," Adeka Optomer SP-150 "," ADEKA OPTOMER SP-160 "(manufactured by ADEKA Corporation) DPI-101 "," DPI-102 "and" DPI-2064S "(all manufactured by Nippon Soda Co., Ltd.)," CIP- 101, BBI-102, BBI-103, BBI-105, TPS-101, DPI-105, MPI-103, MP1-105, , "TPS-102", "TPS-103", "TPS-105", "MDS-103", "MDS-105", "DTS- Quot ;, " PI-2074 " (manufactured by Rhodia), " ILGACURE 250, ILGACURE PAG 103, ILGACURE PAG108, ILGACURE PAG 121 and ILGACURE PAG203 CPI-100P "," CPI-101A "," CPI-210S ", and" CPI-110P "(manufactured by San AiPro Co., Ltd.) -100P " and " CPI-110P " refer to points of hardenability and adhesion .

The content of the component (C) is in the range of 0.5 to 10% by weight based on the entire composition. If the ratio is less than 0.5% by weight, the curing of the adhesive becomes insufficient, and the mechanical strength and the bonding strength are lowered. On the other hand, if the ratio exceeds 10% by weight, the ionic substances in the cured product are increased, The durability is degraded, which is undesirable. The content of the component (C) is preferably from 1 to 5% by weight, and the optical properties such as transparency and the durability performance can be improved by setting the content within this range.

≪ Oxetane compound (D) >

In the photocurable adhesive of the present invention, an oxetane compound represented by the following formula (2) is blended as the component (D). (D), it is possible to improve the speed of developing the adhesive force after light irradiation. In addition, the final adhesive strength when the relative humidity of the application environment is about 45% can be improved. Also, by including the component (D) in the relative humidity of the coating environment which can vary, the adhesive force can be expressed even if the relative humidity of the coating environment fluctuates somewhat.

The content of the component (D) should be 1 to 25% by weight, preferably 1 to 18% by weight, based on the entire composition. By containing the component (D) in a proportion of 1 to 25% by weight, it is possible to improve the adhesive force developing speed after light irradiation and the final adhesive strength when the relative humidity of the application environment is about 45%. When the relative humidity of the coating environment is about 45%, the final adhesive strength is not deteriorated. When the relative humidity of the coating environment is about 45% It is possible to improve the speed of expression of the adhesive force under both humidity conditions. The content of the component (D) is more preferably 1 to 12% by weight.

≪ Oxetane compound (E) >

In the photocurable adhesive of the present invention, an oxetane compound represented by the following formula (3) can be blended as the component (E). (E), it is possible to further improve the speed of developing the adhesive force after the light irradiation and the final adhesive force.

The content of the component (E) is preferably 1 to 18% by weight based on the whole composition. By setting this range, it is possible to further improve the speed of developing the adhesive force after light irradiation and the final adhesive force. The content of the component (E) is more preferably 1 to 12% by weight based on the whole composition.

≪ Photo radical polymerization initiator (F) >

The radical curing component such as the component (B) contained in the photo-curing adhesive of the present invention can be cured by radicals generated when the component (C) is decomposed by light, but in order to obtain a sufficient reaction rate ) Component is preferably incorporated as the photo-radical polymerization initiator. (F) is preferably 10% by weight or less, more preferably 0.1 to 3% by weight based on the whole composition. When the blending amount is 10% by weight or more, the durability is lowered, which is not preferable.

As specific examples of the component (F), there may be mentioned, for example, the following compounds.

Dichloroacetophenone, 4'-tert-butyl-2,2-dichloroacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2- -Methylthiophenyl) -2-morpholinopropane-1-one, 1-hydroxycyclohexylphenylketone,?,? - diethoxyacetophenone, 2-hydroxy- 2-methylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy- 2-methylpropan-1-one, and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) Butan-1-one;

Benzoin ether photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;

Benzophenone type photopolymerization initiators such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenylsulfide and 2,4,6-trimethylbenzophenone;

Thioxanthone photopolymerization initiators such as 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propanedioxanthone;

Trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, and bis (2,4,6-trimethylbenzoyl) phenyl An acylphosphine oxide-based photopolymerization initiator such as phosphine oxide;

Oxime ester-based photopolymerization initiators such as 1,2-octanedione, 1- [4- (phenylthiophenyl)] -, and 2- (O-benzoyloxime);

Camphorquinone and the like.

The component (F) may be used singly or in combination of two or more kinds in accordance with desired performance.

When the photo-radical polymerization initiator of the component (F) is incorporated, the content thereof is preferably 10% by weight or less, more preferably 0.1 to 3% by weight based on the whole composition. If the content of the photo radical polymerization initiator (F) is excessively larger than 10% by weight, sufficient strength may not be obtained, and if the content is insufficient, the adhesive may not be sufficiently cured.

≪ Leveling agent (G) >

In the photocurable adhesive of the present invention, it is preferable to contain a leveling agent of the component (G) for the purpose of obtaining a coating surface excellent in smoothness.

As the component (G), a silicone leveling agent and a fluorine leveling agent can be cited. Various commercially available leveling agents can be used.

The preferable content of the component (G) is 0.01 to 0.5% by weight based on the entire composition. When the addition number is less than 0.01% by weight, the effect of adding the leveling agent is small. On the contrary, when the addition amount is more than 0.5% by weight, the adhesiveness may be deteriorated.

<Other Curable Component>

The photocurable adhesive of the present invention may contain other cation-curable components or radical-curable components in addition to the above-mentioned components (A) to (G).

Examples of the cation-curable component other than the component (A), the component (D) and the component (E) include various epoxy compounds, oxetane compounds and vinyl ether compounds.

Specific examples of the epoxy compound other than component (A) include diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of brominated bisphenol A, phenol novolak type epoxy resin, cresol novolak type Epoxy resin, biphenyl type epoxy resin, hydroquinone diglycidyl ether, resorcin diglycidyl ether, terephthalic acid diglycidyl ester, phthalic acid diglycidyl ester, terminal carboxylic acid polybutadiene and bisphenol A type epoxy resin An addition reaction product of dicyclopentanedioldioxide, limonene dioxide, 4-vinylcyclohexene dioxide, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, poly Tetramethylene glycol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, epoxidized vegetable oil, 2- (3,4-epoxycyclohexyl) Trimethylsilane, trimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, polybutadiene of both terminal hydroxyl groups Diglycidyl ether, an internal epoxide of polybutadiene, a compound in which a double bond of a styrene-butadiene copolymer is partially epoxidized (for example, " Epofriend ", manufactured by Daicel Chemical Industries, Ltd.) -Butylene copolymer and a compound in which an isoprene unit of a block copolymer of polyisoprene is partially epoxidized (for example, " L-207 ", manufactured by KRATON).

Specific examples of the oxetane compound other than the component (D) and the component (E) include monofunctional oxetane containing an alkoxyalkyl group such as 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3- (3-ethyloxetan-3-yl) methoxymethyl] benzene, 1,4-bis [(3-ethyloxetane- 3-yl) methoxy] benzene, 1,2-bis [(3-ethyloxetan-3-yl) methoxy Benzene, 4,4'-bis [(3-ethyloxetan-3-yl) methoxy] biphenyl, 2,2'-bis [ , 3,3 ', 5,5'-tetramethyl-4,4'-bis [(3-ethyloxetan-3-yl) methoxy] biphenyl, 2,7- 3-yl) methoxy] phenyl] methane, bis [2 - {(3-ethyloxetan- Methoxy} phenyl] propane, novolak-type phenol (2-hydroxyethyl) (3-ethyloxetan-3-yl) methoxymethyl] -tri (3-ethyloxetane-3-ethyloxetane) Cyclo [5.2,1.0 ^2,6 ] decane, 2,3-bis [(3-ethyloxetan-3-yl) methoxymethyl] norbornane, 1,1,1-tris [ Methoxymethyl] propane, 1-butoxy-2,2-bis [(3-ethyloxetan-3- yl) methoxymethyl] Ethyl] oxetan-3-yl) methoxy} ethylthio] ethane, bis [{4- 3-yl) methoxy] -2,2,3,3,4,4,5,5-octafluorohexane, 3 - [(3-ethyloxetan- Propyltriethoxysilane, 3 - [(3-ethyloxetan-3-yl) methoxy] propyltrialkoxysilane, 3- , A tetrakis [(3-ethyloxetan-3-yl) methyl] silicate, a 3-ethyloxetan-3-ylmethane And condensation reaction products of the polycondensates of silane tetraols and the like.

Specific examples of the vinyl ether compound include cyclohexyl vinyl ether, 2-ethylhexyl vinyl ether, dodecyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol vinyl ether, cyclohexanedimethanol divinyl Ether, and the like.

The content of the cationically curable component other than the component (A), the component (D) and the component (E) is preferably less than 20% by weight, more preferably less than 10% by weight, And less than 5% by weight.

Examples of the radical-curable component other than the component (B) include various compounds, and examples thereof include (meth) acrylates, (meth) acrylamides, maleimides, (meth) acrylic acid, maleic acid, itaconic acid, (Meth) acrylic aldehyde, (meth) acryloylmorpholine, N-vinyl-2-pyrrolidone, triallyl isocyanurate, divinyl adipate and vinyltrimethoxysilane.

Specific examples of the (meth) acrylates having one (meth) acryloyl group in the molecule include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) Acrylates such as butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, cyclohexyl (Meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (Meth) acrylate, benzyl (Meth) acrylate of a phenol alkylene oxide adduct, (meth) acrylate of a p-cumylphenol alkylene oxide adduct, (meth) acrylate of an o-phenylphenol alkylene oxide adduct, nonylphenol alkylene oxide (Meth) acrylate of an adduct of an alkylene oxide adduct of 2-methoxyethyl (meth) acrylate, ethoxyethoxyethyl (meth) acrylate and 2-ethylhexyl alcohol, Mono (meth) acrylate of triethylene glycol, mono (meth) acrylate of tetraethylene glycol, mono (meth) acrylate of polyethylene glycol Mono (meth) acrylate of dipropylene glycol, mono (meth) acrylate of tripropylene glycol, mono (meth) acrylate of polypropylene glycol (Meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy- (2-ethyl-2-methyl-1,3-dioxolan-4-yl) methyl (meth) acrylate, (2-isobutyl- (Meth) acrylate, glycidyl (meth) acrylate, glycidyl (meth) acrylate, (Meth) acrylate, 2- (meth) acryloyloxyethyl isocyanate, allyl (meth) acrylate, (Meth) acryloyloxyethylhexahydrophthalimide, N- (meth) acryloyloxyethyltetrahydrophthalimide, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2 - (meth) Acryloyloxypropyltrimethoxysilane, 3 (meth) acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, - (meth) acryloyloxypropyldimethoxymethylsilane, 3- (meth) acryloyloxypropyltriethoxysilane, and the like.

Specific examples of the (meth) acrylates other than the (B) component having two or more (meth) acryloyl groups in the molecule include triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) Di (meth) acrylate of a bisphenol A alkylene oxide adduct, urethane (meth) acrylate having a carbon number of 16 or more, polyester (meth) acrylate having a carbon number of 16 or more, polyethylene glycol di (meth) ) Acrylate and an epoxy (meth) acrylate having a carbon number of 16 or more.

Specific examples of the (meth) acrylamides include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N- (Meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide and N, N-diallyl (meth) acrylamide.

Specific examples of the maleimide include N-methylmaleimide, N-hydroxyethylmaleimide, N-hydroxyethyl citraconimide, urethane reaction product of N-hydroxyethyl citraconimide and isophorone diisocyanate, and the like .

The content of the radical-curing component other than the component (B) is preferably less than 20% by weight based on the entire composition.

&Lt; Other components not having curability >

The photocurable adhesive of the present invention may optionally contain other components having no curability within a range not to impair the effect of the present invention. Specific examples thereof include a photosensitizer, a thermal cationic polymerization initiator, a polyol compound, .

Specific examples of the photosensitizer include benzophenone, methyl o-benzoylbenzoate, 2-isopropylthioxanthone, and 9,10-dibutoxyanthracene. Among these, there are compounds corresponding to the photoradical polymerization initiator of the component (F), but the photosensitizer referred to herein functions as a sensitizer for the photocationic polymerization initiator of the component (C). These may be used alone or in combination of two or more.

The content of the photosensitizer is preferably less than 3% by weight based on the total composition.

Specific examples of the thermal cationic polymerization initiator include a benzylsulfonium salt, a thiophenium salt, a thioranium salt, a benzylammonium salt, a pyridinium salt, a hydrazinium salt, a carboxylic acid ester, a sulfonic acid ester, and an amine imide. These initiators can be easily obtained from commercial products, and examples thereof include "ADEKA OPTON CP77" and "ADEKA OPTON CP66" (manufactured by ADEKA Corporation), "CI-2639" , "SANEID SI-80L" and "SANEID SI-1001L" (all manufactured by SANSHIN KAGAKU KOGYO CO., LTD.), "CI-2624" ) And the like.

The content of the thermal cationic polymerization initiator is preferably less than 3% by weight based on the entire composition.

Specific examples of the polyol compound include ethylene glycol, propylene glycol, polyether polyol compound, polyester polyol compound, polycaprolactone polyol compound, and polycarbonate polyol compound.

The mixing ratio of the polyol compound is preferably less than 10% by weight based on the whole composition.

The viscosity of the photocurable adhesive of the present invention is preferably not more than 150 mPa · s at 25 ° C. and preferably not more than 100 mPa · s in order to obtain a coating property which is excellent in coating properties usable in the production process of a polarizing plate, desirable. More preferably 50 mPa 占 퐏 or less.

A small amount of water may be added to the photocurable adhesive of the present invention in order to improve adhesion to a polarizer having a high degree of drying. In this case, the amount of water added is preferably less than 3% by weight, more preferably less than 1% by weight based on the whole composition.

In addition to these, an ion trap agent, an antioxidant, a light stabilizer, a chain transfer agent, a tackifier, a thermoplastic resin, a metal oxide fine particle, a defoaming agent, a pigment, an organic solvent and the like may be blended as long as the effect of the present invention is not impaired.

[Polarizer]

The photo-curable adhesive described above is used for adhering a protective film to a polarizer made of a polyvinyl alcohol-based resin film which is uniaxially stretched and adsorbed and oriented in a dichromatic dye, and thus a protective film is bonded to the polarizer to form a polarizing plate. That is, the polarizing plate according to the present invention is obtained by bonding a protective film to a polarizer made of a polyvinyl alcohol-based resin film which is uniaxially stretched and adsorbed dichromatic dye. The protective film may be bonded to only one side of the polarizer, or may be bonded to both sides of the polarizer. When the protective film is bonded to both surfaces of the polarizer, each of the protective films may be made of the same type of resin or may be made of another kind of resin.

<Polarizer>

The polyvinyl alcohol resin constituting the polarizer is obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include vinyl acetate, a copolymer of vinyl acetate and other monomers copolymerizable therewith, and the like, as well as polyvinyl acetate, which is a homopolymer of vinyl acetate. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers and unsaturated sulfonic acids. The degree of saponification of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol resin may also be modified. For example, a polyvinyl polymer or polyvinyl acetal modified with an aldehyde may be used. The polymerization degree of the polyvinyl alcohol resin is usually in the range of 1,000 to 10,000, preferably 1,500 to 10,000.

The polarizing plate is a step of uniaxially stretching the polyvinyl alcohol resin film, a step of dyeing the polyvinyl alcohol resin film with a dichroic dye, a step of adsorbing the dichroic dye, a step of dyeing the polyvinyl alcohol resin A step of treating the film with an aqueous solution of boric acid, a step of washing with water after treatment with an aqueous solution of boric acid, and a step of bonding the protective film to the uniaxially stretched polyvinyl alcohol-based resin film do.

The uniaxial stretching may be carried out before dyeing with a dichroic dye, or simultaneously with dyeing with a dichroic dye, or after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages. In order to uniaxially stretch, the main stretch may be uniaxially stretched between different rolls, or may be uniaxially stretched using a heat roll. Further, dry stretching may be performed in the atmosphere, or wet stretching may be performed in a state of being swelled by a solvent. The stretching magnification is usually about 4 to 8 times.

In order to dye a polyvinyl alcohol resin film with a dichroic dye, for example, the polyvinyl alcohol resin film may be dipped in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine or dichromatic dye is specifically used.

When iodine is used as the dichroic dye, a method of dying a polyvinyl alcohol resin film in an aqueous solution containing iodine and potassium iodide is generally employed. The content of iodine in this aqueous solution is usually about 0.01 to 0.5 parts by weight per 100 parts by weight of water, and the content of potassium iodide is usually about 0.5 to 10 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution is usually about 20 to 40 占 폚, and the immersion time in the aqueous solution is usually about 30 to 300 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a method of dying and dyeing a polyvinyl alcohol resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in the aqueous solution is usually about 1 × 10 ^{-3 to} 1 × 10 ^-2 parts by weight per 100 parts by weight of water. The aqueous solution may contain an inorganic salt such as sodium sulfate. The temperature of the aqueous solution is usually about 20 to 80 占 폚, and the immersion time in the aqueous solution is usually about 30 to 300 seconds.

The boric acid treatment after dyeing with the dichroic dye is carried out by immersing the dyed polyvinyl alcohol resin film in an aqueous solution of boric acid. The content of boric acid in the aqueous solution of boric acid is usually about 2 to 15 parts by weight, preferably about 5 to 12 parts by weight, per 100 parts by weight of water. When iodine is used as the dichroic dye, the aqueous boric acid solution preferably contains potassium iodide. The content of potassium hyosondide in the aqueous solution of boric acid is usually about 2 to 20 parts by weight, preferably 5 to 15 parts by weight, per 100 parts by weight of water. The immersing time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 占 폚 or higher, preferably 50 to 85 占 폚.

The polyvinyl alcohol resin film after boric acid treatment is usually subjected to water washing treatment. The water washing treatment is carried out, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. After washing with water, drying treatment is carried out to obtain a polarizer. The temperature of the water in the water washing treatment is usually about 5 to 40 캜, and the immersing time is usually about 2 to 120 seconds. The drying process to be performed thereafter is normally carried out using a hot-air dryer or a far-infrared heater. The drying temperature is usually 40 to 100 ° C. The treatment time in the drying treatment is usually about 120 to 600 seconds.

Thus, a polarizer comprising a polyvinyl alcohol-based resin film in which iodine or dichromatic dye as a dichromatic dye is adsorbed and oriented can be obtained.

<Protection film>

Then, the protective film is bonded to one side or both sides of the polarizer using the photo-curable adhesive described above. The triacetylcellulose film, which has been conventionally widely used as a protective film for a polarizer, has a moisture permeability of about 400 g / m 2/24 hr. In the present invention, as a protective film bonded to at least one surface of a polarizer, a resin exhibiting a moisture permeability lower than that of triacetylcellulose A polyester resin, a polycarbonate resin, an acrylic resin, or an amorphous polyolefin resin is used.

The kind of the polyester resin used for the protective film is not particularly limited, but polyethylene terephthalate is particularly preferable in terms of mechanical properties, solvent resistance, scratch resistance, cost and the like. Polyethylene terephthalate means a resin in which at least 80 mol% of the repeating units are composed of ethylene terephthalate, and may contain constituent units derived from other copolymerizable components. Other copolymerization components include isophthalic acid, p-beta-hydroxyethoxybenzoic acid, 4,4'-dicarboxydiphenyl, 4,4'-dicarboxybenzophenone, bis (4- carboxyphenyl) ethane, adipic acid, Dicarboxylic acid components such as sebacic acid, 5-sodium sulfoisophthalic acid, and 1,4-dicarboxycyclohexane; Diol components such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These dicarboxylic acid components and diol components may be used in combination of two or more kinds, if necessary. It is also possible to use a hydroxycarboxylic acid such as p-hydroxybenzoic acid together with the dicarboxylic acid component or the diol component. As the other copolymerization component, a small amount of a dicarboxylic acid component and / or a diol component having an amide bond, a urethane bond, an ether bond, a carbonate bond or the like may be used.

As a production method of the polyester resin, a so-called direct polymerization method in which terephthalic acid and ethylene glycol (and other dicarboxylic acids and / or other diols as necessary) are directly reacted, a method in which dimethylester of terephthalic acid and ethylene glycol Such as a so-called transesterification method, in which a transesterification reaction is carried out with an ester exchange reaction of a dimethyl ester of a carboxylic acid and / or a diol of a carboxylic acid and / or other diol). The polyester resin may contain known additives as required. Examples of additives that can be contained include lubricants, anti-blocking agents, heat stabilizers, antioxidants, antistatic agents, light stabilizers, and impact resistance improvers. However, since transparency is required as a protective film laminated on the polarizing film, the amount of these additives is preferably limited to a minimum.

The protective film made of a stretched polyester resin can be produced by molding the raw resin into a film and subjecting it to uniaxial stretching or biaxial stretching. By conducting the stretching treatment, a film having high mechanical strength can be obtained. The method for producing the stretched polyester resin film is arbitrary and not particularly limited. However, it is preferable that the raw material resin is melted and the unoriented film extruded into a sheet shape is transversely stretched by a tenter at a temperature not lower than the glass transition temperature, And the like.

When a polyester resin is used as a protective film, it is preferable to apply a corona treatment before applying an adhesive to obtain good adhesion, or to use a polyester resin film having a surface with an adhesive treatment layer.

The polycarbonate resin used in the protective film is a polyester formed from carbonic acid and glycol or bisphenol. Among them, an aromatic polycarbonate having a diphenylalkane in its molecular chain is preferably used since it has excellent heat resistance, weather resistance and acid resistance. As such polycarbonate, there can be mentioned 2,2-bis (4-hydroxyphenyl) propane (also called bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, And polycarbonates derived from bisphenols such as hexane, 1,1-bis (4-hydroxyphenyl) isobutane or 1,1-bis (4-hydroxyphenyl) ethane.

As the method of producing the polycarbonate resin film, any method such as a flexible film forming method or a melt extrusion method may be used. As a specific example of the production method, a polycarbonate resin is dissolved in an appropriate organic solvent to prepare a polycarbonate resin solution, which is then softened on a metal support to form a web, the web is peeled from the metal support, Followed by drying to obtain a film.

The acrylic resin used for the protective film is not particularly limited, but is generally a polymer having a methacrylic acid ester as a main monomer and a copolymer in which a small amount of another comonomer component is copolymerized. The methacrylic acid ester which is the main component of the acrylic resin is usually alkyl methacrylate, and methyl methacrylate is particularly preferably used. As the comonomer component, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl-hexyl acrylate and the like are generally used. In addition, aromatic vinyl compounds such as styrene and vinyl cyan compounds such as acrylonitrile may be used as comonomer components.

As the production method of the acrylic resin, arbitrary methods such as bulk polymerization, suspension polymerization and emulsion polymerization can be employed. Among them, bulk polymerization in which no water-soluble component is present in the polymerization system is preferably employed. In order to obtain a desired glass transition temperature or to obtain a viscosity which shows moldability to a preferable film, it is preferable to use a chain transfer agent at the time of polymerization. The amount of the chain transfer agent may be appropriately determined depending on the type and composition of the monomer. The acrylic resin may contain known additives as required. Known additives include, for example, lubricants, anti-blocking agents, heat stabilizers, antioxidants, antistatic agents, light stabilizers, impact resistance improvers, surfactants and the like. However, since transparency is required as a protective film laminated on the polarizing film, the amount of these additives is preferably limited to a minimum.

As the production method of the acrylic resin film, any method such as the melt-extrusion method such as the melt-softening method, the T-die method and the inflation method, or the calender method may be used. Among them, a method of forming a film by bringing at least one side of a film-like material obtained by melt-extruding a raw resin into, for example, a T-die into contact with a roll or a belt is preferable in that a film having good surface properties can be obtained.

The acrylic resin may contain acrylic rubber particles, which are impact modifiers, from the viewpoints of film formability to film and impact resistance of film. The acrylic rubber particles referred to herein are particles composed of an elastomer mainly composed of an acrylate ester as an essential component and substantially of a single layer structure composed of only this elastomer but those having a multilayer structure composed of this elastomer as one layer have. As an example of such an elastomer, a crosslinked elastic copolymer comprising an alkyl acrylate as a main component and another vinyl monomer copolymerizable therewith and a crosslinkable monomer is copolymerized. Examples of the alkyl acrylate as the main component of the elastomer include those having 1 to 8 carbon atoms in the alkyl group such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, Acrylate having an alkyl group of at least one of the above- Examples of other vinyl monomers copolymerizable with the alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid esters such as methyl methacrylate, aromatic vinyls such as styrene Compounds, and vinyl cyan compounds such as acrylonitrile. Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, crosslinkable compounds such as ethylene glycol di (meth) acrylate and butanediol di (Meth) acrylates of polyhydric alcohols, alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylates, and divinylbenzene.

A laminate of a film made of an acrylic resin containing no rubber particles and a film made of an acrylic resin containing rubber particles may also be used as a protective film.

When an acrylic resin is used as a protective film, it is possible to obtain good adhesiveness even without corona treatment by using the composition of the present invention. However, before the application of the adhesive for the purpose of improving the applicability of the adhesive, Corona treatment may be performed.

The amorphous polyolefin-based resin used for the protective film has a polymerization unit which is usually introduced from a polycyclic cyclic olefin such as norbornene or a derivative thereof or dimethano-octahydronaphthalene, and when a double bond remains as in a ring- Is preferably used as a hydrogenation product. The amorphous polyolefin-based resin may be a copolymer of a cyclic olefin and a chain olefin, and a polar group may be introduced. Among them, a thermoplastic saturated norbornene resin is typical. Examples of commercially available amorphous polyolefin resins include "ATON" manufactured by JSR Corporation, "ZEONEX" and "ZEONOR" manufactured by Nippon Zeon Corporation, "APO" and "Apel" manufactured by Mitsui Kagaku Co., . When an amorphous polyolefin-based resin is formed into a film, known methods such as a solvent casting method and a melt extrusion method are suitably used for the film formation.

When an amorphous polyolefin-based resin is used as a protective film, it is preferable to conduct the corona treatment before applying the adhesive in order to obtain good adhesion.

In the polarizing plate used on the viewing side of the liquid crystal display device, the protective film disposed on the viewer side, that is, the opposite side to the liquid crystal cell, can be imparted with antifogging properties. In this case, it is general to provide an antiglare layer having surface irregularities on the surface which becomes the viewer's side of the protective film, that is, the surface opposite to the surface bonded to the polarizer. The antiglare layer is generally formed by a method of imparting unevenness to the active energy ray-curable resin by an embossing method, or a method of imparting unevenness to the active energy ray-curable resin by blending fine particles having a refractive index different from that of the active energy ray- . When the protective film is made of an acrylic resin, a light-diffusing layer in which fine particles having a different refractive index from that of the light-diffusing layer is mixed in the acrylic resin as a binder, and a laminated film of a transparent layer made of an acrylic resin containing no such fine particles, It is also valid to configure. In this case, a laminated film composed of two layers of the light diffusion layer and the transparent layer is bonded to the polarizer on the light diffusion layer side, or a laminated film having a three-layer structure in which both sides of the light diffusion layer are sandwiched by the transparent layer, And a form of bonding to a polarizer. Even in the case where the acrylic resin laminated film imparted with the light-diffusing property is used as a protective film by including such a light-diffusing layer, the above-mentioned antiglare layer is provided on the surface that becomes the viewer side, It is also effective to further enhance the anti-glare performance.

As described above, particularly when an acrylic resin film is used as a protective film, the epoxy resin alone which does not contain an aromatic ring as shown in the above-mentioned Patent Document 6 (Japanese Patent Application Laid-Open No. 2004-245925) , The composition of the present invention gives good adhesion even when such an acrylic resin film is used as a protective film. Therefore, the present invention is particularly useful when an acrylic resin film is used as a protective film.

In the present invention, a protective film composed of a transparent resin film made of a resin selected from the above-described polyester resin, polycarbonate resin, acrylic resin and amorphous polyolefin resin is bonded to at least one side of the polarizer through the photo-curable adhesive described above . When a protective film is bonded to only one side of the polarizer, for example, a pressure-sensitive adhesive layer for bonding to another member such as a liquid crystal cell may be directly provided on the other side of the polarizer.

On the other hand, when the protective film is bonded to both surfaces of the polarizer, the respective protective films may be of the same kind or of different kinds. Concretely, for example, there are a form in which a polyester resin film is bonded to both sides of a polarizer as a protective film, a case in which a polycarbonate resin film is bonded as a protective film to both sides of the polarizer, a form in which an acrylic resin film is bonded to both sides of a polarizer as a protective film , A form in which an amorphous polyolefin-based resin film is bonded to both surfaces of a polarizer as a protective film, and a mode in which one side of the polarizer is bonded to one side of a transparent resin selected from polyester resin film, polycarbonate resin film, acrylic resin film and amorphous polyolefin- A resin film is bonded as a protective film, and on the other surface of the polarizer, a transparent resin different from the one side of the protective film of one side is selected from a polyester resin film, a polycarbonate resin film, an acrylic resin film and an amorphous polyolefin- Protecting film The standing bonding form, such as may be employed. Further, a transparent resin film selected from a polyester resin film, a polycarbonate resin film, an acrylic resin film and an amorphous polyolefin resin film is bonded to one side of the polarizer as a protective film, and a poly A polyester resin film, an ester resin film, a polycarbonate resin film, an acrylic resin film, and an amorphous polyolefin resin film may be bonded to each other using another transparent resin film as a protective film. When the protective film is bonded to both surfaces of the polarizer, the two protective films may be bonded stepwise one by one, or both surfaces may be bonded in one step.

In the case where a protective film is bonded to both surfaces of a polarizer and one of them is a resin film other than a polyester resin film, a polycarbonate resin film, an acrylic resin film and an amorphous polyolefin resin film, A preferable example is a cellulose resin film. In addition, a protective film composed of a polyester resin film, a polycarbonate resin film, an acrylic resin film, and an amorphous polyolefin resin film adhered to one side of the polarizer is adhered through the photo-curable adhesive described above according to the present invention, The protective film to be bonded to the side face may be bonded via another adhesive. For example, when a protective film made of a resin film having a relatively high moisture permeability such as a cellulose-based resin film is provided on one surface of a polarizer, an adhesive other than an epoxy-based adhesive such as a polyvinyl alcohol- It is also good. However, since the photo-curing adhesive according to the present invention gives a high adhesive force to the cellulose-based resin film exemplified here, it is advantageous to use the same adhesive on both sides of the polarizer, since the operation becomes simple.

On the other hand, examples of the cellulose-based resin that can be used as a protective film include cellulose ester partially or fully esterified products such as cellulose acetate ester, propionic acid ester, butyric acid ester and mixed ester thereof. Specifically, triacetylcellulose, diacetylcellulose, cellulose acetate propionate, cellulose acetate butyrate and the like can be mentioned. Examples of commercially available products of such a cellulose ester based resin film include "Fujifilm TD80", "Fujifilm TD80UF" and "Fujifilm TD80UZ" manufactured by Fuji Film Co., Ltd., "KC8UX2M" manufactured by Konica Minolta Opto &Quot; KC8UY ". A cellulose-based resin film imparted with an optical compensation function may also be used. Examples of such an optical compensation film include a film containing a compound having a retardation adjusting function in a cellulose resin, a film coated with a compound having a retardation adjusting function on the surface of a cellulose resin film, a cellulose resin film having a single- And a film obtained by biaxial stretching. Examples of commercially available cellulose-based optical compensation films include "Wide View Film WV BZ 438" and "Wide View Film WV EA" manufactured by Fuji Film Co., Ltd., "KC4FR-1" manufactured by Konica Minolta Opto Co., &Quot; and " KC4HR-1 &quot;.

Examples of other transparent resins other than polyester resins, polycarbonate resins, acrylic resins and amorphous polyolefin resins that can be used as one of the protective films include polysulfone resins and alicyclic polyimide resins, .

The bonding film may be subjected to the bonding treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment or the like before bonding to the polarizer. The surface of the protective film opposite to the bonding surface to the polarizer may have various treatment layers such as a hard coat layer, an antireflection layer, and an antiglare layer. The thickness of the protective film is usually in the range of about 5 to 200 mu m, preferably 10 to 120 mu m, and more preferably 10 to 85 mu m.

[Polarizing plate production method]

The polarizing plate of the present invention is characterized in that at least one of the above-described polarizers and the bonding surfaces of the transparent resin film made of a resin selected from a resin selected from a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin- A bonding step of bonding a polarizer and a protective film to each other through an adhesive layer to be obtained and a curing step of curing a photo-curable adhesive interposed as an adhesive layer between the polarizer and the protective film . &Lt; / RTI &gt;

&Lt; Adhesive application step &

In the adhesive applying step, the photo-curable adhesive described above is applied to at least one of the bonding surfaces of the polarizer and the protective film. When a photocurable adhesive is directly applied to the surface of the polarizer or the protective film, there is no particular limitation on the method of applying the film. For example, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Also, a method of pliing the above-described photo-curable adhesive between the polarizer and the protective film and then pressing the film with a roll or the like to uniformly stretch and widen the film can also be used.

The atmospheric temperature of the adhesive application step is preferably 15 to 30 占 폚, particularly preferably 20 to 25 占 폚. The relative humidity of the coating atmosphere is preferably 80% or less, more preferably 70% or less, still more preferably 30 to 70%, and particularly preferably 40 to 60%.

<Bonding Step>

After the photocurable adhesive is applied in this way, it is provided to the bonding process. In this bonding step, for example, in the case where a photocurable adhesive is applied to the surface of the polarizer in the previous coating step, a protective film is overlapped with the photocurable adhesive, and when a photocurable adhesive is applied to the surface of the protective film in the previous coating step, Overlap. When a photo-curing adhesive is poured between the polarizer and the protective film, the polarizer and the protective film overlap in this state. When a protective film is bonded to both surfaces of a polarizer, both surfaces of the polarizer are covered with a protective film by a photo-curable adhesive on both sides of the polarizer when the photo-curable adhesive of the present invention is used. Usually, in this state, both surfaces are pressed with a roll or the like from both sides (when the protective film is overlaid on one side of the polarizer, on the side of the polarizer and the protective film, or when the protective film is overlapped on both sides of the polarizer, on the side of the protective film on both sides). The material of the roll may be metal or rubber. The rolls disposed on both sides may be the same material or different materials.

<Curing Process>

As described above, the state in which the polarizer and the protective film are bonded to each other through the uncured photo-curable adhesive is subsequently provided to the curing process. In this curing step, the photo-curable adhesive is irradiated with active energy rays, and the adhesive layer including the epoxy compound, (meth) acrylate, oxetane compound, and the like is cured to adhere the polarizer and the protective film. When a protective film is bonded to one surface of the polarizer, the active energy ray may be irradiated on either the polarizer side or the protective film side. When the protective film is bonded to both surfaces of the polarizer, the active energy ray is irradiated from one side of the protective film while the protective film is bonded to both surfaces of the polarizer through the photo-curable adhesive, and the photo- It is advantageous. However, in the case where an ultraviolet absorber is blended in one of the protective films (for example, in the case where a cellulose-based resin film in which an ultraviolet absorber is blended is used as one protective film), when the active energy ray is ultraviolet rays, Ultraviolet rays are irradiated from the side of the protective film not containing the ultraviolet absorber.

As the active energy ray, visible ray, ultraviolet ray, X ray, electron ray and the like can be used, but ultraviolet ray is generally used because it is easy to handle and has a sufficient curing speed. The light source of the active energy ray is not particularly limited, but a light source having a wavelength of 400 nm or less, such as a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a high pressure mercury lamp, a chemical lamp, a black light lamp, , An LED lamp, or the like can be used.

The light irradiation intensity to the photo-curing adhesive is determined not only with respect to the object composition but also with the irradiation intensity of the wavelength region effective for activating the polymerization initiator is 1 (1) as UV-B (medium wavelength ultraviolet light of 280 to 320 nm) To 3,000 mW / cm &lt; 2 &gt;. If the irradiation intensity is less than 1 mW / cm 2, the reaction time becomes too long. If the irradiation intensity exceeds 3,000 mW / cm 2, heat radiated from the lamp and heat generated during polymerization of the photo- There is a possibility of causing deterioration of the semiconductor device.

The light irradiation time to the photo-curable adhesive is controlled for each composition to be cured, and is not particularly limited, but is set so that the integrated light quantity represented by the product of irradiation intensity and irradiation time is 10 to 5,000 mJ / cm 2 in UV-B . When the accumulated light quantity is less than 10 mJ / cm 2, the generation of active species originating from the polymerization initiator is not sufficient and the curing of the adhesive layer may be insufficient. On the other hand, when the accumulated light quantity exceeds 5,000 mJ / cm 2, It is disadvantageous to productivity improvement.

In curing the photo-curable adhesive by irradiating an active energy ray, it is preferable to cure the photo-curing adhesive under conditions that do not deteriorate various functions of the polarizing plate, such as the polarization degree, transmittance and hue of the polarizer, or transparency of the protective film.

In the thus obtained polarizing plate, the thickness of the adhesive layer is usually 50 占 퐉 or less, preferably 20 占 퐉 or less, more preferably 10 占 퐉 or less.

[Optical member]

In the use of the polarizing plate, an optical member having an optical function exhibiting an optical function other than the polarization function may be laminated on one side thereof. Examples of the optical layer that is laminated on the polarizing plate for the purpose of forming the optical member include various ones used for forming a reflective layer, a transflective reflective layer, a light diffusion layer, a retarder, a condenser, a brightness enhancement film, . The reflective layer, the transflective reflective layer and the light-diffusing layer are used in the case of forming an optical member made of a polarizing plate of a reflection type, a semi-transmission type, a diffusion type, or both of them.

The reflection type polarizing plate is used in a liquid crystal display device of the type that reflects and displays incident light on the viewer side. Since a light source such as a backlight can be omitted, it is easy to make the liquid crystal display device thinner. Further, the transflective type polarizing plate is used in a liquid crystal display device of the type that displays as a reflection type in a bright place and a light source such as a backlight in a dark place. In the optical member as the reflection type polarizing plate, for example, a protective film on a polarizer may be provided with a foil or a vapor deposition film made of a metal such as aluminum to form a reflection layer. The optical member as the transflective polarizing plate can be formed by making the reflective layer a half mirror, or containing a pearl pigment or the like, and adhering a reflective plate exhibiting light transmittance to the polarizing plate. On the other hand, the optical member as the diffusion-type polarizing plate can be obtained by various methods such as, for example, a method of applying a matting treatment to a protective film on a polarizing plate, a method of applying a resin containing a fine particle, a method of adhering a fine- Thereby forming a concave-convex structure.

The formation of the optical member as the polarizing plate for both of the reflection diffusion and the reflection can be performed by, for example, a method of providing a reflective layer reflecting the concavo-convex structure on the fine uneven structure surface of the polarizing plate. The reflective layer of the micro concavo-convex structure diffuses the incident light by diffuse reflection to prevent directivity and glare, and has an advantage that the unevenness of the light and shade can be suppressed. Further, the resin layer or film containing fine particles has an advantage that the incident light and the reflected light thereof are diffused when they penetrate the fine particle-containing layer, whereby the nonuniformity of light and shade can be further suppressed. The reflective layer in which the surface micro concavo-convex structure is reflected can be formed, for example, by laying the metal directly on the surface of the fine uneven structure by vapor deposition such as vacuum deposition, ion plating, sputtering, plating or the like. Examples of the fine particles to be blended to form the surface micro concavo-convex structure include inorganic fine particles made of silica, aluminum oxide, titanium oxide, zirconia, tin oxide, indium oxide or the like having an average particle size of 0.1 to 30 탆, crosslinked or uncrosslinked polymers Based organic fine particles can be used.

On the other hand, the above-described retardation plate as the optical layer is used for the purpose of compensating the retardation by the liquid crystal cell or the like. Examples thereof include a birefringent film made of stretched films of various plastics, a film in which a discoating liquid crystal or a nematic liquid crystal is aligned and fixed, and a film in which the liquid crystal layer is formed on a film substrate. In this case, a cellulose-based film such as triacetyl cellulose is preferably used as a film base for supporting the aligned liquid crystal layer.

Examples of the plastic forming the birefringent film include polyolefins such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate and polypropylene, polyarylate, polyamide and amorphous polyolefin resins have. The stretched film may be processed in a suitable manner such as one-axis or two-axis. Further, a birefringent film in which the refractive index in the thickness direction of the film is controlled by applying a shrinking force and / or a stretching force under adhesion with the heat-shrinkable film may be used. Further, two or more retardation plates may be used in combination for the purpose of controlling optical characteristics such as broadening.

The light-collecting plate is used for optical path control or the like, and can be formed as a prism array, a lens array, or a dot-laid sheet.

The brightness enhancement film is used for the purpose of improving brightness in a liquid crystal display or the like. Examples of such a brightness enhancement film include a reflection type linearly polarized light separation sheet designed to laminate a plurality of thin films having different refractive index anisotropy and generate anisotropy in reflectance, An orientation film of a steric liquid crystal polymer, and a circularly polarized light separation sheet in which the alignment liquid crystal layer is supported on a film base.

The optical member includes a polarizing plate and a single or two or more optical layers selected from the above-mentioned reflective layer, transmissive reflective layer, light diffusing layer, retardation plate, light collecting plate, Can be sieved. In this case, two or more optical layers such as a light-diffusing layer, a retardation plate, a light-collecting plate and a brightness enhancement film may be disposed. The arrangement of each optical layer is not particularly limited.

The various optical layers forming the optical member are integrated with the polarizing plate by using an adhesive, but the adhesive used therefor is not particularly limited as long as the adhesive layer can be formed satisfactorily. It is preferable to use a pressure-sensitive adhesive (also referred to as pressure-sensitive adhesive) from the viewpoints of simplicity of the bonding operation and prevention of occurrence of optical deformation. As the pressure-sensitive adhesive, an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyether, or the like may be used as the base polymer. Among them, the acrylic pressure sensitive adhesive has excellent optical transparency, maintains appropriate wettability and cohesive force, exhibits excellent adhesion to a substrate, has weather resistance and heat resistance, and exhibits peeling problems such as floating or peeling under the conditions of heating and humidification It is preferable to select and use it. In the acrylic pressure-sensitive adhesive, an alkyl ester of (meth) acrylic acid having an alkyl group having a carbon number of 20 or less such as methyl group, ethyl group or butyl group and an acrylic monomer containing a functional group such as (meth) acrylic acid or hydroxyethyl (meth) An acrylic copolymer having a weight average molecular weight of 100,000 or more, which is blended so that the temperature is preferably 25 占 폚 or lower, more preferably 0 占 폚 or lower, is useful as the base polymer.

The pressure-sensitive adhesive layer may be formed on the polarizing plate by, for example, dissolving or dispersing the pressure-sensitive adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare a liquid having a solid concentration of 10 to 40% by weight, Or a method in which a pressure-sensitive adhesive layer is formed on a separate film in advance, and the pressure-sensitive adhesive layer is formed by attaching it to a polarizing plate. The thickness of the pressure-sensitive adhesive layer is determined depending on the adhesive strength and the like, but is preferably in the range of about 1 to 50 mu m.

The adhesive layer may contain a filler such as glass fiber, glass beads, resin beads, metal powder or other inorganic powder, a pigment or a colorant, an antioxidant, or an ultraviolet absorber if necessary. Examples of the ultraviolet absorber include a salicylic ester compound, a benzophenone compound, a benzotriazole compound, a cyanoacrylate compound, and a nickel complex salt compound.

[Liquid crystal display device]

The optical member as described above can be disposed on one side or both sides of the liquid crystal cell to form a liquid crystal display device. The liquid crystal cell to be used is arbitrary. For example, a liquid crystal display device is formed using various liquid crystal cells such as an active matrix drive type represented by a thin film transistor type or a simple matrix drive type represented by a super twisted nematic type can do. The optical members provided on both sides of the liquid crystal cell may be the same or different.

(Example)

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples, the percentages indicating the amounts used or the content are based on the weight unless otherwise specified. Also, the% humidity indicates the relative humidity at 23 ° C.

In the examples and comparative examples, the components used for preparing the photocurable adhesive composition are as follows, and they are expressed by the name of a compound or each symbol (trade name itself or a part thereof).

( A): Epoxy Compound

CEL-2021: an alicyclic epoxy compound represented by the formula (4), "Celloxide 2021P" manufactured by Daicel Chemical Industries, Ltd.

(A) 'Component: An epoxy compound other than the component (A)

jER-828: "jER-828" manufactured by Japan Epoxy Resin Co., Ltd., bisphenol A type epoxy resin.

Component (B): poly (meth) acrylate compound

HDDA: 1,6-hexanediol diacrylate, "Light Acrylate 1,6HX-A", manufactured by Kyoeisha Chemical Co., Ltd.

FM-400: neo-pentyl glycol, hydroxypivalic acid and esterification reaction product of acrylic acid, "KAYAR RAD FM-400" manufactured by Nippon Kayaku Co., Ltd.

M-203: tricyclodecane dimethiol diacrylate, "Aronix M-203", manufactured by Toagosei Co., Ltd. Diacrylates of diols having 12 carbon atoms.

M-309: trimethyrol propane triacrylate, "Aronix M-309" manufactured by Toagosei Co., Ltd.

(B) 'component: a (meth) acrylate compound other than the component (B)

M-240: Polyethylene glycol (average number of repeats: about 4) diacrylate, "Aronix M-240" manufactured by Toagosei Co., Ltd. Diacrylates of diols having an average carbon number of 8 having an ether structure.

HPA: 2-hydroxypropyl acrylate

(C) Ingredient: Gwangyang ion polymerization initiator

CPI-100P: a propylene carbonate solution containing 50% of an active ingredient containing triarylsulfonium hexafluorophosphate as a main component; " CPI-100P " List the number of active ingredients in the table.

Component (D): Oxetane compound represented by the formula (2)

OXT-101: 3-ethyl-3-hydroxymethyloxetane, "Aronoxetane OXT-101" manufactured by Doago Kosai Co., Ltd.

Component (E): The oxetane compound represented by the formula (3)

OXT-221: 3-ethyl-3 - [(3-ethyloxetan-3-yl) methoxymethyl] oxetane, "Aronoxetane OXT-221" manufactured by Doago Kosai Co.,

(F) Component: Photo radical polymerization initiator

Irg 184: 1-hydroxycyclohexyl-phenyl-ketone, " Irgacure 184 "

(G): Leveling agent

8019Add: Silicon leveling agent " 8019 Additive " manufactured by Toray Dow Corning Incorporated.

Other ingredients

Propylene carbonate (solvent introduced from CPI-100P)

[Preparation of photocurable adhesive composition]

Each of the components shown in Tables 1 to 4 was blended in respective ratios, and the mixture was stirred and mixed according to the conventional method to prepare a photo-curable adhesive composition. As described above, since "CPI-100P" used as the component (C) is a propylene carbonate solution containing 50% of the active ingredient, the component (C) and the propylene carbonate are shown separately in the table. That is, the compounding amount of " CPI-100P " in the table means the ratio of the effective component, and the amount of the " CPI-100P " itself is an amount of the amount shown in the column of component (C) .

The viscosity of the obtained composition at 25 캜 was measured by an E-type viscometer manufactured by Toki Sangyo Co.,

[Production of polarizer]

Here, the following two types of films were used as protective films.

Drawn norbornene resin film: thickness 70 mu m, trade name "ZEONOR film", manufactured by Nippon Zeon Co., Ltd. This film was subjected to a corona discharge treatment and then provided for bonding with a polarizer.

Acrylic resin film: thickness 80 占 퐉, trade name "Technoroy S001", manufactured by Sumitomo Chemical Co., Ltd. This film was subjected to a corona discharge treatment and then provided for bonding with a polarizer.

The composition prepared in advance on the corona discharge treated surface of the drawn norbornene resin film and on the corona discharge treated surface of the acrylic resin film was applied with a bar coater to a thickness of 3 탆. Subsequently, a polarizer in which iodine was adsorbed and oriented in polyvinyl alcohol was sandwiched between these two films, and three films were simultaneously bonded with a roller. The UV absorber was irradiated from the surface of the drawn norbornene resin film with an ultraviolet ray irradiating device (lamp is a high-pressure mercury lamp manufactured by Eye Graphics Co., Ltd.) having a belt conveyer with a polarizer having a protective film bonded on both surfaces in this manner, B) to cure the adhesive composition.

This experiment was carried out under the conditions of 23 캜 and 45% humidity, and at 23 캜 and at a humidity of 65%.

[Evaluation test]

The polarizing plate after irradiation with ultraviolet rays was evaluated for the adhesive force development rate, final adhesion and durability by the following methods, and the results are summarized in Tables 1 to 4.

&Lt; Adhesive force development rate >

The acrylic resin film and the polarizer were peeled off by hand after 3 minutes from the ultraviolet irradiation, and it was evaluated that the adhesive force of the acrylic resin film was higher than that of the acrylic resin film. The adhesive strength was judged to be the following four levels from the shape and force when peeling by hand.

◎: Material breakage of acrylic resin film.

○: When peeling slowly with care, material does not break but strong adhesion.

?: There is no strength to break the material, but it is not weak enough to peel off with a little force.

X: It is very weak to be peeled off with a slight force.

<Final Adhesive Force>

○ Cutter insertion test

One day after ultraviolet irradiation, the blade of the cutter knife was inserted at an angle from above the acrylic resin film, and the following four levels were judged from the shape and force at that time.

◎: Even if the blade did not enter or enter, the acrylic resin film tore due to the strength.

○: Although the blade was inserted, the acrylic resin film was sliced at the interface due to the resistance.

△: The blade enters, but the blade is not weak enough to proceed with a little force at the interface.

X: The blade is inserted, and the blade is weak enough at the interface to proceed with a little force.

<Durability>

A heat and shock cycle test in which the test was carried out under the conditions of 23 DEG C and 45% humidity and the cycle of placing the polarizing plate for one day or more after ultraviolet irradiation for 60 minutes at -35 DEG C and then for 60 minutes at + 70 DEG C . At this time, it was evaluated as &quot; Good &quot; when no appearance defects were confirmed, &quot; Good &quot;

<Overall evaluation>

The above evaluations were collectively evaluated at the following six levels.

&Amp; cir &amp;: &amp; cir &amp;: in the condition that none of x and DELTA is present and the final adhesive force is at least one side

A: There is no x, and the final adhesive force is ⊚ in one condition, but there is one in △.

○ B: There is no ×, but the final adhesive force does not become ◎ in any condition.

DELTA A: There is no x, but the final adhesive force does not become &quot; A &quot;, and &quot; DELTA &quot;

? B: Under the conditions of a humidity of 45%, the adhesive force development speed, the final adhesive force, and the durability are both ◯ or more.

×: In any of the conditions of the humidity of 45%, there is X in either of the adhesive force development speed, the final adhesive strength, and the durability.

The adhesive composition of the present invention shown in Tables 1 and 2 had an overall evaluation of? B or more.

On the other hand, the compositions of Comparative Examples shown in Table 3 and Table 4 were evaluated as "X".

That is, the adhesive composition of the present invention was suitable for the production of a polarizing plate.

First, the embodiments of Tables 1 and 2 will be described.

The compositions of Examples 3 to 5 containing 1 to 18% by weight of the component (E) exhibited an adhesive force of ⊚ even at a humidity of all degrees or a final adhesive force of ⊚ at either one of the humidity. That is, the compositions of Examples 3 to 5 were superior to the compositions of Example 1 and Example 2, which did not contain the component (E). The composition of Example 8 in which the component (B) of Example 5 was changed to FM-400 which is a diacrylate of a diol having 5 to 10 carbon atoms was also the same as Example 5.

The composition of Example 7 in which a portion of HDDA of the composition of Example 5 was replaced with HPA had a satisfactory result at a humidity of 65% but was satisfactory at a humidity of 45%.

The composition of Example 5 is the same as the composition of Example 6 in which the component (A) is 29% by weight and the component (B) is 45% by weight or the component (B) The rate of adhesive force development and the final adhesive force were superior to those of the compositions of Examples 9 and 10, which were not rates.

All of the compositions of Example 11 and Example 12 had good adhesive force results at a humidity of 45%. However, these compositions exceeded the preferable upper limit of the component (D), and the composition of Example 11 exhibited insufficient adhesive force development rate at an adhesive strength at a humidity of 65%, and the composition of Example 12 exhibited an adhesive force development rate and a final adhesive force Was insufficient.

Next, comparative examples of Table 3 and Table 4 will be described.

The composition of Comparative Example 1 in which the component (A) was changed to the component (A) 'had a good final adhesive force but a poor adhesive force development rate.

The composition of Comparative Example 2 containing no component (A) and the component (B) in a predetermined amount, the composition of Comparative Example 3 and Comparative Example 4 containing no component (B), the component (D) , All of the evaluation items of the adhesive force were all defective. The composition of Comparative Example 7 also had poor durability. The composition of Comparative Example 5 and Comparative Example 6, which did not contain the component (D), showed poor adhesive force development rate at a humidity of 45%.

The compositions of Comparative Examples 8 and 9, in which the component (B) was changed to the component (B) ', all exhibited insufficient adhesive force development rate at a humidity of 45%, poor adhesive force development rate at a humidity of 65% did.

The photocurable adhesive composition of the present invention is preferably used in the production of a polarizing plate since it has a low viscosity and is easy to apply in the form of a thin film, and exhibits excellent speed and final adhesive force between the polarizer and the protective film after irradiation with light and excellent durability of the obtained polarizing plate .

Claims (12)

A transparent resin film made of a resin selected from the group consisting of a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin resin is applied to a polarizer made of a polyvinyl alcohol resin film which is uniaxially stretched and in which a dichroic dye is adsorbed and oriented As an adhesive composition for bonding a protective film comprising:
(A) an epoxy compound having at least two alicyclic epoxy groups represented by the following formula (1) in the molecule,

(B) a poly (meth) acrylate of a polyol having 2 to 15 carbon atoms (provided that the polyether polyol having 3 or more repeating number of alkylene oxide units is excluded)
(C) a photocationic polymerization initiator, and
(D) an oxetane compound represented by the following formula (2)

The content of the components (A) to (D)
Component (A): 20 to 80 wt%
Component (B): 10 to 55 wt%
(C): 0.5 to 10 wt%
(D): 1 to 25% by weight. The method according to claim 1,
Wherein the component (A) is an epoxy compound represented by the following formula (4).

3. The method according to claim 1 or 2,
Wherein the component (B) is a di (meth) acrylate of a diol having 5 to 10 carbon atoms (provided that the polyether diol having 3 or more repeating number of alkylene oxide units is excluded). 3. The method according to claim 1 or 2,
Wherein the content of the component (A) and the component (B) is 35 to 75 wt% and 10 to 35 wt%, respectively, in the composition. 3. The method according to claim 1 or 2,
Wherein the composition further contains an oxetane compound represented by the following formula (3) as a component (E) in a content of 1 to 18 wt% in the composition.

3. The method according to claim 1 or 2,
(F) a photo-radical polymerization initiator in a proportion of not more than 10% by weight in the composition. 3. The method according to claim 1 or 2,
(G) a leveling agent in an amount of 0.01 to 0.5% by weight in the composition. A polarizer made of a polyvinyl alcohol-based resin film which is uniaxially stretched and in which a dichroic dye is adsorbed and oriented is made of a resin selected from the group consisting of a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin resin through an adhesive A polarizing plate comprising a transparent resin film and a protective film joined together,
Wherein the adhesive is formed from the photo-curable adhesive composition according to any one of claims 1 to 5. The polarizing plate according to claim 1, A polarizer made of a polyvinyl alcohol-based resin film which is uniaxially stretched and in which a dichroic dye is adsorbed and oriented is made of a resin selected from the group consisting of a polyester resin, a polycarbonate resin, an acrylic resin and an amorphous polyolefin resin through an adhesive A method for producing a polarizing plate by bonding a protective film made of a transparent resin film, comprising:
An adhesive applying step of applying the photo-curable adhesive composition according to claim 1 or 2 to at least one of bonding surfaces of the polarizer and the protective film;
A bonding step of bonding the polarizer and the protective film through an adhesive layer to be obtained,
And a curing step of curing the photo-curable adhesive composition interposed as the adhesive layer between the polarizer and the protective film bonded to each other. An optical member characterized in that at least one other optical layer is laminated on the polarizing plate according to claim 8. 11. The method of claim 10,
And at least one of the other optical layers is a retardation plate. The liquid crystal display device according to claim 10, wherein the optical member is disposed on one side or both sides of the liquid crystal cell.