阅读说明：本技术 光固化粘接剂组合物、光固化粘接剂、偏光板及光学设备 (Photocurable adhesive composition, photocurable adhesive, polarizing plate, and optical device ) 是由 钱晓春 胡春青 于培培 于 2019-04-29 设计创作，主要内容包括：本发明提供了一种光固化粘接剂组合物、光固化粘接剂、偏光板及光学设备。该光固化粘接剂组合物包括：组分A,为含有如下结构的氧杂环丁烷化合物<Image he="247" wi="617" file="DDA0002045838100000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中R代表苯基、联苯基、萘基,0≤n≤4；组分B：为具有环氧基的化合物；组分C：为阳离子聚合光引发剂。通过选用特定的氧杂环丁烷化合物与具有环氧基的化合物以及阳离子聚合光引发剂进行配合使用,使所形成的光固化粘接剂的附着力、固化性以及对偏光片和保护膜的粘合性得到改善。(The invention provides a photo-curing adhesive composition, a photo-curing adhesive, a polarizing plate and an optical device. The photo-curable adhesive composition includes: component A is an oxetane compound having the following structure Wherein R represents phenyl, biphenyl and naphthyl, and n is more than or equal to 0 and less than or equal to 4; and (B) component: is a compound having an epoxy group; and (3) component C: is a cationic polymerization photoinitiator. By selecting and using a specific oxetane compound, a compound with an epoxy group and a cationic polymerization photoinitiator in a matching manner, the adhesion and the curing property of the formed photocuring adhesive and the adhesion of the polarizer and the protective film are improved.)

1. A photocurable adhesive composition, comprising:

component A is an oxetane compound having the following structure

and (B) component: is a compound having an epoxy group;

and (3) component C: is a cationic polymerization photoinitiator.

2. The photo-curable adhesive composition according to claim 1, wherein component A is

3. The light-curable adhesive composition according to claim 1, wherein the component B comprises:

component B1: a polyglycidyl ether of a polyhydric alcohol having 2 to 10 carbon atoms;

component B2: is a polymer with epoxy groups.

4. The photo-curable adhesive composition according to claim 3, wherein said component B1 is selected from any one or more of the group consisting of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, dimethylolcyclohexane diglycidyl ether, 1, 9-nonanediol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tri-or tetraglycidyl ether, and di-or triglycidyl ethers of ethylene oxide isocyanurate adducts.

5. The photocurable adhesive composition according to claim 3, wherein said component B2 has a Tg of 20 ℃ or higher and an Mw of 1000 to 30000, preferably 3000 to 20000, more preferably 5000 to 15000, wherein Mw is a weight average molecular weight obtained by polystyrene conversion of a molecular weight measured by GPC.

6. The light-curable adhesive composition according to claim 3, wherein the component B2 is formed by polymerizing a monomer B1, a monomer B2 and optionally a monomer B3, wherein the monomer B1 is a compound having an epoxy group and an ethylenically unsaturated group, the ethylenically unsaturated group being a vinyl group or an acryl group, preferably the monomer B1 is glycidyl acrylate, glycidyl methacrylate, 3, 4-epoxycyclohexyl acrylate or 3, 4-epoxycyclohexyl methacrylate; the monomer b2 is monofunctional methacrylate having 1 to 10 carbon atoms, and preferably the monomer b2 is one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate and benzyl methacrylate; the monomer b3 is an alkenyl compound different from the monomer b1, preferably any one of the group consisting of an aromatic group-containing vinyl compound, a monofunctional acrylate, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide, the aromatic group-containing vinyl compound is styrene or α -methylstyrene, and the monofunctional acrylate is selected from any one or more of the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isooctyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate and benzyl acrylate.

7. The light-curable adhesive composition according to claim 6, wherein the component B2 comprises, by weight, 10-60% of monomer B1, 10-70% of monomer B2 and 0-60% of monomer B3.

8. The photo-curable adhesive composition according to claim 1, wherein the component C is one or more selected from the group consisting of iodonium salt, sulfonium salt, and arylferrocenium salt.

9. A photo-curable adhesive composition according to any one of claims 2 to 8, wherein the component A is present in an amount of 25 to 55%, preferably 25 to 45%, by weight based on the photo-curable adhesive composition; the weight content of the component B1 is 10-45%, the weight content of the component B2 is 20-80%, and the weight content of the component C is 3-5%.

10. A photocurable adhesive obtained by polymerizing a photocurable adhesive composition, wherein the photocurable adhesive composition is the photocurable adhesive composition according to any one of claims 1 to 9.

11. A polarizing plate comprising a polarizer and a protective film bonded to the polarizer by an adhesive, wherein the adhesive is the light-curable adhesive according to claim 10.

12. An optical device comprising a polarizing plate, wherein the polarizing plate is the polarizing plate according to claim 11.

Technical Field

The invention relates to the field of optical materials, in particular to a light-cured adhesive composition, a light-cured adhesive, a polarizing plate and optical equipment.

Background

In recent years, liquid crystal displays have been widely used in various display devices due to their characteristics of low power consumption, low voltage operation, lightness and small volume. The liquid crystal display may include many elements such as a liquid crystal cell, a polarizing plate, a phase difference film, a prism sheet, a light-diffusing film, a light-guiding plate, a light-reflecting sheet, and the like. For this reason, improvements are being actively made to increase productivity and improve brightness by reducing the number of films used or thinning the films or sheets, and to make the liquid crystal display more lightweight.

The polarizing plate includes a polarizer made of a polyvinyl alcohol (PVA) resin dyed with dichroic dye or iodine, and a protective film stacked on one surface or both surfaces of the polarizer, wherein an adhesive is disposed between the polarizer and the protective film. Triacetyl cellulose (TAC) films have been widely used as protective films. However, the TAC film has a disadvantage in that it is deformed in a high-temperature and high-humidity environment. Therefore, protective films made of various materials capable of replacing TAC films have been developed, and concepts of using polyethylene terephthalate (PET) films, cycloolefin polymer (COP) films, acrylic films, or combinations of these films alone have been proposed.

Adhesives such as acrylic adhesives, dry laminating adhesives prepared by mixing a polyurethane resin solution and a polyisocyanate resin solution, styrene/butadiene/rubber adhesives, epoxy adhesives, polyvinyl alcohol adhesives, polyurethane adhesives, adhesives containing a compound having a polyester ionomer urethane resin and a glycidyl group, and thermosetting adhesives have been developed, but the problem of adhesion of these adhesives to different films is a factor to be considered, and the viscosity of the composition, the thickness that can be produced, the acid resistance, the alkali resistance, and the heat resistance are also factors to be considered.

Therefore, different oxetane monomers are developed, the oxetane compounds generally have the characteristics of low viscosity, low toxicity, high polymerization speed, excellent thermal stability and mechanical properties and the like, the application of the oxetane compounds to a cationic curing system can accelerate the polymerization speed and improve the performance of a cured product, but the actual application of the monomer still has obvious defects, the types of the compounds in the market are obviously limited, the comprehensive properties such as curing speed, hardness and the like are difficult to balance, and particularly in the application of a polarizing plate, the problem of the overall adhesion of the system after the oxetane compounds are introduced needs to be further optimized.

Disclosure of Invention

The invention mainly aims to provide a light-curing adhesive composition, a light-curing adhesive, a polarizing plate and an optical device, which aim to solve the problem of insufficient adhesion of the light-curing adhesive in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a photo-curable adhesive composition comprising: component A is an oxetane compound having the following structure

Wherein R represents phenyl, biphenyl and naphthyl, and n is more than or equal to 0 and less than or equal to 4; and (B) component: is a compound having an epoxy group; and (3) component C: is a cationic polymerization photoinitiator.

Further, the above component A isOr

Further, the component B comprises: component B1: a polyglycidyl ether of a polyhydric alcohol having 2 to 10 carbon atoms; component B2: is a polymer with epoxy groups.

Further, the above component B1 is selected from any one or more of the group consisting of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, dimethylolcyclohexane diglycidyl ether, 1, 9-nonanediol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tri-or tetraglycidyl ether, and di-or triglycidyl ether of an ethylene oxide isocyanurate adduct.

Further, the component B2 has a Tg of 20 ℃ or higher and an Mw of 1000 to 30000, preferably 3000 to 20000, and more preferably 5000 to 15000, wherein Mw is a weight average molecular weight obtained by polystyrene conversion of a molecular weight measured by GPC.

Further, the component B2 is formed by polymerizing a monomer B1, a monomer B2 and an optional monomer B3, wherein the monomer B1 is a compound having an epoxy group and an ethylenically unsaturated group, the ethylenically unsaturated group is a vinyl group or an acryloyl group, and preferably the monomer B1 is glycidyl acrylate, glycidyl methacrylate, 3, 4-epoxy cyclohexyl acrylate or 3, 4-epoxy cyclohexyl methacrylate; the monomer b2 is a monofunctional methacrylate having 1 to 10 carbon atoms, preferably the monomer b2 is one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate and benzyl methacrylate; the monomer b3 is an alkenyl compound different from the monomer b1, preferably any one of the group consisting of an aromatic group-containing vinyl compound, a monofunctional acrylate, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide, the aromatic group-containing vinyl compound is styrene or α -methylstyrene, and the monofunctional acrylate is any one or more selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isooctyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate and benzyl acrylate.

Further, the component B2 comprises, by weight, 10-60% of a monomer B1, 10-70% of a monomer B2 and 0-60% of a monomer B3.

Further, the component C is one or more selected from the group consisting of iodonium salt, sulfonium salt and aryl ferrocenium salt.

Further, the weight content of the component A is 25-55%, preferably 25-45% based on the photo-curing adhesive composition; the weight content of the component B1 is 10-45%, the weight content of the component B2 is 20-80%, and the weight content of the component C is 3-5%.

According to another aspect of the present application, there is provided a photocurable adhesive obtained by polymerizing a photocurable adhesive composition, wherein the photocurable adhesive composition is any one of the photocurable adhesive compositions described above.

According to still another aspect of the present application, there is provided a polarizing plate including a polarizer and a protective film bonded to the polarizer by an adhesive, which is the above-described light-curable adhesive.

According to still another aspect of the present application, there is provided an optical apparatus including a polarizing plate, which is the above-described polarizing plate.

By applying the technical scheme of the invention, the adhesion force and the curing property of the formed photocuring adhesive and the adhesion property of the polarizer and the protective film are improved by selecting the specific oxetane compound, the compound with the epoxy group and the cationic polymerization photoinitiator for matching use.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As analyzed in the background of the present application, the oxetane compound of the prior art has the characteristics of low viscosity, low toxicity, high polymerization speed, excellent thermal stability and mechanical properties, but in practical application, the problem that the curing speed and hardness in curing are difficult to balance still exists, especially in the application of a polarizing plate, the overall bonding effect of the adhesive after introducing the oxetane compound is not ideal, and in order to solve the problem, the present application provides a photocurable adhesive composition, a photocurable adhesive, a polarizing plate and an optical device.

In one exemplary embodiment of the present application, there is provided a photocurable adhesive composition comprising a component a, a component B and a component C, wherein the component a is an oxetane compound having the following structure

Wherein R represents phenyl, biphenyl and naphthyl, and n is more than or equal to 0 and less than or equal to 4; the component B is a compound with an epoxy group; and the component C is a cationic polymerization photoinitiator.

The application selects the specific oxetane compound, the compound with the epoxy group and the cationic polymerization photoinitiator for matching use, so that the adhesion and the curing property of the formed photocuring adhesive and the adhesion of the polarizer and the protective film are improved.

Through test verification, the component A is

Or

In one embodiment of the application, the component B comprises a component B1 and a component B2, wherein the component B1 is polyglycidyl ether of a polyhydric alcohol with 2-10 carbon atoms; component B2 is a polymer having epoxy groups. The adhesion of the photocurable adhesive is further improved by blending the two epoxy-containing compounds with an oxetane compound.

Preferably, the above component B1 is selected from any one or more of the group consisting of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, dimethylolcyclohexane diglycidyl ether, 1, 9-nonanediol diglycidyl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tri-or tetraglycidyl ether, and di-or triglycidyl ether of an ethylene oxide isocyanurate adduct.

In order to improve the coating workability of the photocurable adhesive and ensure the adhesion, the component B2 preferably has a Tg of 20 ℃ or higher (measured in the same manner as a conventional measurement method using a Differential Scanning Calorimeter (DSC) at a temperature rise rate of 10 ℃/min), an Mw of 1000 to 30000, preferably 3000 to 20000, and more preferably 5000 to 15000, where Mw is a weight average molecular weight obtained by converting a molecular weight measured by GPC into polystyrene. When Mw of the component B2 is less than 1000, the effect of improving the adhesion between the polarizer and the protective film is insignificant, and when Mw exceeds 30000, coatability is lowered, increasing the difficulty of construction.

In one embodiment of the present application, the above component B2 is formed by polymerization of monomer B1, monomer B2 and optionally monomer B3. Component B2 is a polymer with low Mw, and when such a polymer is to be produced by a conventional polymerization method, it is usually necessary to increase the chain transfer agent and/or the polymerization initiator. When a polymer formed using a large amount of a chain transfer agent is used, cationic curability and/or adhesive force of the composition are liable to be reduced, and storage stability of the composition is liable to be reduced. Therefore, in order to avoid the problems caused by high-temperature polymerization using a large amount of chain transfer and/or polymerization initiators, the monomer b1 is preferably a compound having an epoxy group and an ethylenically unsaturated group, the ethylenically unsaturated group being a vinyl group or an acryl group, and the monomer b1 is preferably glycidyl acrylate, glycidyl methacrylate, 3, 4-epoxycyclohexyl acrylate or 3, 4-epoxycyclohexyl methacrylate; the monomer b2 is a monofunctional methacrylate having 1 to 10 carbon atoms, preferably the monomer b2 is one or more selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate and benzyl methacrylate; the monomer b3 is an alkenyl compound different from the monomer b1, preferably any one of the group consisting of an aromatic group-containing vinyl compound, a monofunctional acrylate, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide, the aromatic group-containing vinyl compound is styrene or α -methylstyrene, and the monofunctional acrylate is any one or more selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isooctyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate and benzyl acrylate.

The monomer B1 and the monomer B2 are copolymerized as an essential structural monomer unit with the component B1 and the component a, which are cationic curable compounds. The monomer b1 is particularly preferably glycidyl methacrylate, and the monomer b2 is particularly preferably methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate or benzyl methacrylate, and the monomer b3 may be further added from the viewpoint of adjusting the reactivity, the system viscosity, or the like.

Preferably, the component B2 comprises 10-60% of monomer B1, 10-70% of monomer B2 and 0-60% of monomer B3 in percentage by weight, and when the monomer B3 contains styrene, the weight content of the styrene in the component B2 is 5-45%, preferably 10-40%; when the monomer B3 contains monofunctional acrylate, the weight content of monofunctional acrylate in the component B2 is 1-30%, preferably 5-25%; preferably, the component B2 comprises methyl methacrylate as a monomer B2 with the weight content of 10-70% and styrene as a monomer B3 with the weight content of 1-50%; preferably, the component B2 comprises 10 to 60 weight percent of glycidyl methacrylate as a monomer B1, 10 to 70 weight percent of methyl methacrylate as a monomer B2 and 1 to 30 weight percent of monofunctional acrylate with a hydrocarbon group having 1 to 10 carbon atoms as a monomer B3. The control of the dosage of the styrene and the monofunctional acrylate is utilized to further adjust the activity, viscosity and volume shrinkage of a reaction system formed by the composition and the stability of a formed binder.

In one embodiment of the present application, the above component C is one or more selected from the group consisting of iodonium salts, sulfonium salts, arylferrocenium salts, preferably a compound having a structure represented by the following formula (I) and/or (II):

wherein R is₁And R₂Each independently represents hydrogen, C₁-C₂₀Straight or branched alkyl of (2), C₄-C₂₀Cycloalkylalkyl or alkylcycloalkyl of (A), and acyclic-CH in these groups₂-optionally substituted by-O-, -S-or 1, 4-phenylene; r₃And R₄Each independently represents hydrogen, C₁-C₂₀Straight or branched alkyl of (2), C₄-C₂₀Cycloalkylalkyl or alkylcycloalkyl, C₆-C₂₀Substituted or unsubstituted aryl of (a), and acyclic-CH in these radicals₂-optionally substituted by-O-, -S-or 1, 4-phenylene; r₅Represents C₆-C₂₀Substituted or unsubstituted aryl of (1), C₆-C₂₀Substituted or unsubstituted alkylaryl of, C₁-C₂₀Straight or branched alkyl of (2), C₄-C₂₀Cycloalkylalkyl or alkylcycloalkyl, substituted or unsubstituted phenylthiophenyl, and the acyclic-CH in these groups₂-optionally substituted by carbonyl, -O-, -S-or 1, 4-phenylene; r₆And R₇Each independently represents an alkyl group, a hydroxyl group, a,An alkoxy group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an arylthiocarbonyl group, an acyloxy group, an arylthio group, an aryl group, a heterocyclic hydrocarbon group, an aryloxy group, an alkylsulfinyl group, an arylsulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a hydroxy (poly) alkyleneoxy group, a substitutable amino group, a cyano group, a nitro group, or a halogen atom; m is ₁、m₂Each represents R₆And R₇The number of (a) is selected from 0, 1, 2, 3 or 4; x^-Each independently represents M^-、ClO₄ ^-、CN^-、HSO₄ ^-、NO₃ ^-、CF₃COO^-、(BM₄)^-、(SbM₆)^-、(AsM₆)^-、(PM₆)^-、Al[OC(CF₃)₃]₄ ^-Sulfonate ion, B (C)₆M₅)₄ ^-Or [ (Rf)_bPF_6-b]^-Wherein M is a halogen, Rf independently represents an alkyl group in which 80% or more of hydrogen atoms are substituted with fluorine atoms, and b represents an integer of 1 to 5. The substance is used as a cationic polymerization photoinitiator, so that the curing rate of the photo-curing adhesive composition is improved.

As a preferred structure, in the compounds of the structures represented by the formulae (I) and (II): r₁And R₂Each independently represents hydrogen, C₁-C₁₂Straight or branched alkyl of (2), C₄-C₁₀Cycloalkylalkyl or alkylcycloalkyl of (A), and acyclic-CH in these groups₂-is optionally substituted by-O-; r₃And R₄Each independently represents hydrogen, C₁-C₁₀Straight or branched alkyl of (2), C₄-C₁₀Cycloalkylalkyl or alkylcycloalkyl, C₆-C₁₂And a substituted or unsubstituted aryl group of (A), and the acyclic-CH in these groups₂-optionally substituted by-O-, -S-or 1, 4-phenylene; r₅Represents C₆-C₁₀Substituted or unsubstituted aryl of (1), C₆-C₁₀Substituted or unsubstituted alkylaryl, substituted or unsubstituted thiophenylphenyl, and the acyclic-CH in these groups₂-optionally substituted by carbonyl, -O-, -S-or 1, 4-phenylene; r₆And R₇Is represented by C₁-C₁₀Straight or branched alkyl of (2), C ₁-C₁₀Linear or branched alkoxy of (C)₁-C₁₀Alkylcarbonyl and halogen.

Commercially available cationic photoinitiators of the same type of structure may also be used in component C of the present invention, examples include (but are not limited to): PAG20001, PAG20001s, PAG20002s, PAG30201, PAG30101, etc., manufactured by Tronly, and Irgacure250, manufactured by BASF, etc.

In the photo-curing adhesive composition, the amount of each component can refer to the amount of the corresponding component in the prior art, preferably, the photo-curing adhesive composition is taken as a reference, and the weight content of the component a is 25-60%, preferably 25-55%, and more preferably 25-45%; the weight content of the component B1 is 10-45%, preferably 10-35%, the weight content of the component B2 is 15-80%, preferably 20-80%, more preferably 15-35%, and the weight content of the component C is 3-5%, preferably 5%.

It will be apparent to those skilled in the art that the photocurable adhesive used in the present invention may optionally be added with organic and/or inorganic auxiliaries commonly used in the art, including, but not limited to, leveling agents, dispersants, curing agents, surfactants, solvents, etc., as required by the product application. In addition, other sensitizers and/or photoinitiators may be added to the adhesive for compounding without adversely affecting the application of the composition.

According to application requirements, one or more macromolecules or high molecular compounds can be optionally added into the light-cured adhesive to improve the application performance, and the macromolecules or high molecular compounds can be polyalcohol or polyester polyol; polymers having no reactive functional group, which are generally resins having acidic functional groups such as phenolic hydroxyl groups and carboxyl groups, may also be optionally added.

In another exemplary embodiment of the present application, there is provided a photocurable adhesive obtained by polymerizing a photocurable adhesive composition, wherein the photocurable adhesive composition is any one of the photocurable adhesive compositions described above.

Since the photo-curing adhesive composition of the present application selects and uses a specific oxetane compound, a compound having an epoxy group, and a cationic polymerization photoinitiator in combination, the adhesion, curability, and adhesion to a polarizer and a protective film of the formed photo-curing adhesive are improved.

In still another exemplary embodiment of the present application, there is provided a polarizing plate including a polarizer and a protective film bonded to the polarizer by an adhesive, which is the above-described light-curable adhesive. The light-cured adhesive has good adhesiveness, acid resistance, alkali resistance and excellent thermal stability, so that the polarizing plate using the light-cured adhesive as the adhesive has long service life and good optical performance.

The photocurable adhesive of the present application is useful for bonding a protective film to a polarizer made of a polyvinyl alcohol resin film, for example, for bonding a protective film to a polarizer made of a polyvinyl alcohol resin film uniaxially stretched and having a dichroic dye adsorbed and oriented, and thus bonding the protective film to the polarizer to produce a polarizing plate. The protective film can be only attached to one side of the polaroid, and can also be attached to two sides of the polaroid. In the case where the protective films are bonded to both surfaces of the polarizer, the protective films may be formed of the same type of resin or may be formed of different types of resins.

Based on the above applications of the present invention, the polarizing plate can be fabricated using a process flow conventional in the art. Typically, the method of making comprises: a protective film is attached to one surface or both surfaces of the polarizing plate using a photocurable adhesive, and the photocurable adhesive is cured by irradiation with light.

More specific process flows may include:

coating: applying a photocurable adhesive to the protective film in an uncured state to form an adhesive-applied surface;

a second laminating step: attaching a polarizing plate to the adhesive-coated surface of the protective film;

③ a curing process: the photocurable adhesive is cured by irradiation with light to form an adhesive layer.

In the process of manufacturing the polarizing plate, a protective film may be attached to one surface or both surfaces. Preferably, at least one of the protective films on both sides has other optical functions.

As the polarizer, a conventional kind in the art, for example, a polyvinyl alcohol-based resin film that has been uniaxially stretched, and has been adsorbed-oriented with iodine or a dichroic dye, may be used.

In still another exemplary embodiment of the present application, there is provided an optical apparatus including a polarizing plate, which is the above-described polarizing plate.

When a polarizing plate is used, an optical member obtained by laminating an optical layer exhibiting an optical function other than a polarizing function on one side thereof may be used. The optical member may be a laminate of two or more layers, which is obtained by combining a polarizing plate with one or more optical layers selected from the reflective layer, the semi-transmissive reflective layer, the light scattering layer, the retardation plate, the light collecting plate, and the brightness enhancement film, depending on the purpose of use. The various optical layers forming the optical member are integrated with the polarizing plate by using an adhesive. By disposing the above optical member on one side or both sides of the liquid crystal cell, a liquid crystal display device can be manufactured.

The present invention is further illustrated by the following examples, which should not be construed as limiting the scope of the invention.

1. Preparation of Photocurable adhesive

The raw materials were uniformly mixed with reference to the formulations shown in the tables to obtain a photocurable adhesive composition (unless otherwise specified, the listed parts are parts by mass).

2. Evaluation of Performance

The photocurable adhesives obtained in examples and comparative examples were defoamed and applied to a triacetyl cellulose (TAC) protective film (trade name) having a thickness of 80 μm using a bar coaterFujitech, Fujitech), the film thickness was 10 μm, and then a polyvinyl alcohol-iodine polarizing plate was attached thereto. Then, the same adhesive was applied to the other side of the polarizing plate to form a coating film having a thickness of 10 μm, and a norbornene resin film (product name: ZEONOR, OPTES) was bonded to the surface. Then, a mercury lamp (Exposure machine model RW-UV20101, cumulative reception 2000 mJ/cm)²Radiant energy of) to cure.

The adhesion, curing performance and adhesion performance were evaluated by the following specific evaluation methods and criteria:

(1) adhesion force

The adhesion force is tested by an ARCOTEST dyne pen, the scribing lines are evenly distributed, the biggest dyne pen without any bead point within 3 seconds is the dyne value test, and the smaller the surface dyne value is, the larger the surface tension of the adhesion bottom layer is, so that the adhesion is more favorable.

(2) Adhesion Property

The adhesiveness of protective films (i.e., TAC film and norbornene film) different on both sides was evaluated separately and classified as follows:

a: the protective film could not be peeled off from the polarizer at the interface, and the film was damaged by forced peeling, indicating excellent adhesion;

b, the protective film can be peeled off from the polarizer at the interface, and the film is not damaged, which shows that the adhesiveness is good;

c: a condition of floating or no adhesion at all occurred immediately after curing-indicating poor adhesion.

(3) Curing Properties

The TAC film and the norbornene film were peeled off from the polarizing plate, and then the surface condition of the cured film was observed with reference to GB1728-79 surface drying time measuring method-touch method, and evaluated as follows:

a: no stickiness-indicating good curability;

b: in the case of tackiness, the curing property was poor.

3. Specific formulation and evaluation results