WO2020221178A1 - Photocurable adhesive composition, photocurable adhesive, polarizer and optical device - Google Patents

Abstract

Provided are a photocurable adhesive composition, a photocurable adhesive, a polarizer and an optical device. The photocurable adhesive composition comprises a component A: an oxetane compound (aa) containing the following structure, in which R represents phenyl, biphenyl, or naphthyl, and 0 ≤ n ≤ 4; a component B: a compound having an epoxy group; and a component C: a cationic polymerization photoinitiator. By selecting and using the specific oxetane compound, the compound having an epoxy group, and the cationic polymerization photoinitiator, the adhesive force, curability and adhesion of the formed photocurable adhesive to the polarizer and protective film are improved.

Description

Light-curing adhesive composition, light-curing adhesive, polarizing plate and optical equipment Technical field

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

Background technique

In recent years, liquid crystal displays have been widely used in various display devices due to their low power consumption, low voltage operation, lightweightness and small size. The liquid crystal display may include many elements, such as liquid crystal cells, polarizing plates, retardation films, prism sheets, diffuser films, light guide plates, light reflection sheets, and the like. For this reason, improvements are being actively made by reducing the number of films used or making films or sheets thinner to increase productivity and improve brightness, and to make liquid crystal displays more portable.

The polarizing plate includes a polarizing plate made of polyvinyl alcohol (PVA) resin dyed with dichroic dye or iodine, and a protective film stacked on one or both surfaces of the polarizing plate, wherein the polarizing plate and the protective film Set the adhesive between. Triacetyl cellulose (TAC) films have been widely used as protective films. However, the disadvantage of TAC film is that it deforms in a high temperature and high humidity environment. Therefore, protective films made of various materials that can replace TAC films were developed, and polyethylene terephthalate (PET) films, cycloolefin polymer (COP) films, acrylic films, or The concept of the combination of these films is constantly being proposed.

Acrylic adhesive, dry laminated adhesive made by mixing polyurethane resin solution and polyisocyanate resin solution, styrene/butadiene/rubber adhesive, epoxy adhesive, polyvinyl alcohol adhesive , Polyurethane adhesives, adhesives containing compounds with polyester ionomer polyurethane resins and glycidyl groups, thermosetting adhesives and other adhesives are constantly being developed, but these adhesives adhere to different films The force problem is a factor that needs to be considered, and the viscosity of the composition, the thickness that can be made, acid resistance, alkali resistance, and heat resistance are also factors that need to be considered.

For this reason, different oxetane-based monomers have been developed. These oxetane-based compounds generally have the characteristics of low viscosity, low toxicity, fast polymerization speed, excellent thermal stability and mechanical properties, etc., which are used in cationic curing. The system can accelerate the polymerization speed and improve the performance of the cured product. However, the practical application of such monomers still has obvious shortcomings. The outstanding performance is that the types of compounds on the market are limited, and the comprehensive properties such as curing speed and hardness are difficult to balance, especially in polarized light. In the application of the board, the problem of the overall adhesion of the system after the introduction of oxetane compounds needs to be further optimized.

Summary of the invention

The main purpose of the present invention is to provide a light-curing adhesive composition, light-curing adhesive, polarizing plate and optical equipment to solve the problem of insufficient adhesion of the light-curing adhesive in the prior art.

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

Wherein R represents phenyl, biphenyl, naphthyl, 0≤n≤4; component B: a compound with epoxy group; component C: a photoinitiator for cationic polymerization.

Further, the above component A is

Further, the aforementioned component B includes: component B1: a polyglycidyl ether of a polyhydric alcohol having 2 to 10 carbon atoms; and component B2: a polymer having an epoxy group.

Further, the above component B1 is selected from 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 Glycidyl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tri- or tetra-glycidyl ether, and isocyanuric epoxy Any one or more of the group consisting of di- or triglycidyl ethers of ethane adducts.

Further, the Tg of the above component B2 is greater than or equal to 20°C, and the Mw is 1,000 to 30,000, preferably 3,000 to 20,000, and more preferably 5,000 to 15,000, where Mw refers to polystyrene conversion of the molecular weight measured by GPC And the weight average molecular weight obtained.

Further, the above component B2 is formed by polymerizing monomer b1, monomer b2 and optional monomer b3, wherein monomer b1 is a compound having epoxy groups and ethylenically unsaturated groups, and the ethylenic unsaturated groups are Vinyl or acryl, preferably monomer b1 is glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl acrylate or 3,4-epoxycyclohexyl methacrylate; monomer b2 It is a monofunctional methacrylate having 1 to 10 carbon atoms, preferably monomer b2 is selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, methacrylic acid Butyl ester, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Any one of octyl ester, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate, and benzyl methacrylate, or Multiple; monomer b3 is an alkenyl compound different from monomer b1, preferably composed of aromatic group-containing vinyl compounds, monofunctional acrylates, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide Any one in the group, the aromatic group-containing vinyl compound is styrene or α-methylstyrene, and the monofunctional acrylate is selected from 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, acrylic acid Any one or more of the group consisting of isononyl ester, decyl acrylate, isodecyl acrylate, and benzyl acrylate.

Further, in terms of weight percentage, the above-mentioned component B2 includes 10-60% of monomer b1, 10-70% of monomer b2 and 0-60% of monomer b3.

Further, the aforementioned component C is selected from one or more combinations of iodonium salts, sulfonium salts, and aryl ferrocene salts.

Further, on the basis of the above-mentioned light-curable adhesive composition, the weight content of component A is 25-55%, preferably 25-45%; the weight content of component B1 is 10-45%, and the weight content of component B2 The weight content is 20 to 80%, and the weight content of component C is 3 to 5%.

According to another aspect of the present application, a light-curing adhesive is provided, which is formed by polymerization of a light-curing adhesive composition, the light-curing adhesive composition being any of the above-mentioned light-curing adhesive combinations Things.

According to another aspect of the present application, there is provided a polarizing plate, which includes a polarizer and a protective film bonded to the polarizer by an adhesive, the adhesive being the above-mentioned light-curing adhesive.

According to another aspect of the present application, there is provided an optical device including a polarizing plate, the polarizing plate being the aforementioned polarizing plate.

Applying the technical solution of the present invention, by selecting a specific oxetane compound, a compound having an epoxy group, and a cationic polymerization photoinitiator for use, the adhesion, curability and curability of the formed photocurable adhesive The adhesion to the polarizer and protective film is improved.

Detailed ways

It should be noted that the embodiments in this application and the features in the embodiments can be combined with each other if there is no conflict. Hereinafter, the present invention will be described in detail in conjunction with embodiments.

As analyzed in the background art of this application, the prior art oxetane compounds have the characteristics of low viscosity, low toxicity, good polymerization speed, excellent thermal stability and mechanical properties, but still have curability in practical applications. In order to solve this problem, the curing speed and hardness are difficult to balance, especially in the application of polarizers. The overall adhesion effect of the adhesive after the introduction of oxetane compounds is not ideal. In order to solve this problem, this application provides A light-curing adhesive composition, light-curing adhesive, polarizing plate and optical equipment.

In a typical embodiment of the present application, a light-curable adhesive composition is provided, including component A, component B and component C, wherein component A is an oxetane having the following structure Compound

Wherein R represents phenyl, biphenyl, naphthyl, 0≤n≤4; component B is a compound with epoxy group; component C is a photoinitiator for cationic polymerization.

In this application, a specific oxetane compound is used in conjunction with a compound having an epoxy group and a cationic polymerization photoinitiator to make the formed photocurable adhesive have adhesion, curability, and protection of the polarizer. The adhesion of the film is improved.

After verification, the above component A is

The effect is more obvious.

In an embodiment of the present application, the aforementioned component B includes component B1 and component B2. Component B1 is a polyglycidyl ether of a polyhydric alcohol with 2 to 10 carbon atoms; component B2 is an epoxy group Of polymers. The combination of the above two epoxy-containing compounds and the oxetane compound can further improve the adhesiveness of the photocurable adhesive.

Preferably, the aforementioned component B1 is selected from 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 Glyceryl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tri- or tetraglycidyl ether, and isocyanuric acid ethylene oxide Any one or more of the group consisting of di- or triglycidyl ethers of alkane adducts.

In order to improve the coating performance of the light-curing adhesive and ensure the adhesion, it is preferable that the Tg of the above component B2 is greater than or equal to 20°C (the same as the conventional measurement method in the prior art, that is, using a differential scanning calorimeter (DSC) , The value measured at a temperature increase rate of 10°C/min), Mw is 1,000 to 30,000, preferably 3,000 to 20,000, and more preferably 5,000 to 15,000, where Mw means the molecular weight measured by GPC is converted into polystyrene Weight average molecular weight obtained by conversion. When the Mw of the above component B2 is less than 1,000, the effect of improving the adhesion between the polarizer and the protective film is not obvious, and when the Mw exceeds 30,000, the coating property is reduced and the construction difficulty is increased.

In an embodiment of the present application, the aforementioned component B2 is formed by polymerization of monomer b1, monomer b2 and optional monomer b3. Component B2 is a polymer with low Mw. When it is desired to produce such a polymer by a normal polymerization method, it is usually necessary to increase a chain transfer agent and/or a polymerization initiator. When a polymer formed of a large amount of a chain transfer agent is used, the cationic curability and/or adhesive force of the composition tends to be lowered, and the storage stability of the composition also tends to be lowered. 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 with epoxy groups and ethylenically unsaturated groups. It is vinyl or acryl, preferably monomer b1 is glycidyl acrylate, glycidyl methacrylate, 3,4-epoxycyclohexyl acrylate or 3,4-epoxycyclohexyl methacrylate; monomer b2 is a monofunctional methacrylate having 1 to 10 carbon atoms, preferably monomer b2 is selected from methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, methyl Butyl acrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, methyl Any one of the group consisting of octyl acrylate, isooctyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, isodecyl methacrylate, and benzyl methacrylate Or more; monomer b3 is an alkenyl compound different from monomer b1, preferably composed of vinyl compound containing aromatic group, monofunctional acrylate, acrylonitrile, methacrylonitrile, acrylamide and methacrylamide Any one of the group, the aromatic group-containing vinyl compound is styrene or α-methylstyrene, and the monofunctional acrylate is selected from methyl acrylate, ethyl acrylate, propyl acrylate, and 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, Any one or more of the group consisting of isononyl acrylate, decyl acrylate, isodecyl acrylate, and benzyl acrylate.

The monomer b1 and the monomer b2 as essential structural monomer units are copolymerized with the component B1 and the component A which are the cation curable compound. And the above-mentioned monomer b1 is particularly preferably glycidyl methacrylate, and the above-mentioned monomer b2 is particularly preferably methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate and benzyl methacrylate to adjust the reactivity , System viscosity, etc. can be further added monomer b3.

Preferably, in terms of weight percentage, component B2 includes 10-60% of monomer b1, 10-70% of monomer b2, and 0-60% of monomer b3. When monomer b3 contains styrene, the component The weight content of styrene in B2 is 5 to 45%, preferably 10 to 40%; when monomer b3 contains monofunctional acrylate, the weight content of monofunctional acrylate in component B2 is 1 to 30%, preferably 5-25%; preferably component B2 includes 10-70% by weight methyl methacrylate as monomer b2, and 1-50% by weight styrene as monomer b3; preferably component B2 includes weight Glycidyl methacrylate with a content of 10-60% as monomer b1, methyl methacrylate with a weight content of 10 to 70% as monomer b2, and a weight content of 1-30% with carbon atoms of 1 to A monofunctional acrylate of a hydrocarbon group of 10 is used as the monomer b3. Using the aforementioned control of the amount of styrene and monofunctional acrylate, the activity, viscosity, and volume shrinkage rate of the reaction system formed by the composition can be further adjusted, as well as the stability of the formed binder.

In an embodiment of the present application, the aforementioned component C is selected from one or more combinations of iodonium salts, sulfonium salts, and aryl ferrocene salts, and preferably has the following formula (I) and/ Or the compound of the structure shown in (II):

Wherein, R ₁ and R ₂ each independently represent hydrogen, a C ₁ -C ₂₀ linear or branched alkyl group, a C ₄ -C ₂₀ cycloalkylalkyl group or an alkylcycloalkyl group, and among these groups The acyclic -CH ₂ -can be optionally substituted by -O-, -S- or 1,4-phenylene; R ₃ and R ₄ each independently represent hydrogen, C ₁ -C ₂₀ linear or Branched chain alkyl, C ₄ -C ₂₀ cycloalkyl alkyl or alkyl cycloalkyl, C ₆ -C ₂₀ substituted or unsubstituted aryl, and the non-cyclic -CH ₂ -in these groups may Optionally substituted by -O-, -S- or 1,4-phenylene; R ₅ represents C ₆ -C ₂₀ substituted or unsubstituted aryl, C ₆ -C ₂₀ substituted or unsubstituted alkyl Aryl, C ₁ -C ₂₀ linear or branched alkyl, C ₄ -C ₂₀ cycloalkylalkyl or alkylcycloalkyl, substituted or unsubstituted phenylthiophenyl, and these groups The acyclic -CH ₂ -in the group can be optionally substituted by a carbonyl, -O-, -S- or 1,4-phenylene group; R ₆ and R ₇ each independently represent an alkyl group, a hydroxyl group, or an alkoxy group Group, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, aryl, heterocyclic hydrocarbon, aryloxy, alkylsulfinyl, Arylsulfinyl, alkylsulfonyl, arylsulfonyl, hydroxy(poly)alkyleneoxy, substitutable amino, cyano, nitro or halogen atom; m ₁ and m ₂ represent R ₆ and the number of R ₇ is selected from 2, 3 or 4; X ^- independently represents ^{_{M -, ClO 4 -, CN}} -, HSO 4 -, NO 3 -, CF 3 COO -, (BM 4 ^{_{) -, (SbM 6) -}} , (AsM 6) -, (PM 6) -, Al [OC (CF 3) 3] 4 -, sulfonate _{ion, B (C 6 M 5)} 4 - , or [(an Rf ) _b PF _6-b ] ^- , where M is a halogen, Rf each independently represents an alkyl group in which ≥80% of hydrogen atoms are replaced by fluorine atoms, and b represents an integer of 1 to 5. The above-mentioned substances are used as cationic polymerization photoinitiators to increase the curing rate of the photocurable adhesive composition.

As a preferred structure, in the compounds represented by formula (I) and (II): R ₁ and R ₂ each independently represent hydrogen, C ₁ -C ₁₂ linear or branched alkyl, C ₄ -C ₁₀ Cycloalkylalkyl or alkylcycloalkyl, and the acyclic -CH ₂ -in these groups may be optionally substituted by -O-; R ₃ and R ₄ each independently represent hydrogen, C ₁ -C ₁₀ straight or branched chain alkyl groups, C ₄ -C ₁₀ cycloalkylalkyl groups or alkylcycloalkyl groups, C ₆ -C ₁₂ substituted or unsubstituted aryl groups, and these groups are non-cyclic- CH ₂ -may be optionally substituted by -O-, -S- or 1,4-phenylene; R ₅ represents C ₆ -C ₁₀ substituted or unsubstituted aryl, C ₆ -C ₁₀ substituted or Unsubstituted alkyl aryl, substituted or unsubstituted phenylthio phenyl, and the acyclic -CH ₂ -in these groups can be optionally substituted by carbonyl, -O-, -S- or 1,4- Substituted by phenylene; R ₆ and R ₇ represent C ₁ -C ₁₀ linear or branched alkyl, C ₁ -C ₁₀ linear or branched alkoxy, C ₁ -C ₁₀ alkylcarbonyl And halogen.

Commercially available cationic photoinitiators with similar structures can also be used in component C of the present invention. Examples include (but not limited to): PAG20001, PAG20001s, PAG20002, PAG20002s, PAG30201, PAG30101, etc. produced by Tronly, etc. Irgacure250 produced by the company.

In the light-curing adhesive composition of the present application, the amount of each component can refer to the amount of the corresponding component in the prior art, preferably based on the light-curing adhesive composition, and the weight content of component A is 25- 60%, preferably 25 to 55%, more preferably 25 to 45%; the weight content of component B1 is 10 to 45%, preferably 10 to 35%, and the weight content of component B2 is 15 to 80%, preferably It is 20 to 80%, more preferably 15 to 35%, and the weight content of component C is 3 to 5%, preferably 5%.

According to product application requirements, the photocurable adhesive in the application of the present invention can optionally be added with organic and/or inorganic additives commonly used in the field, including but not limited to leveling agents, dispersants, curing agents, surface Active agents, solvents, etc. are obvious to those skilled in the art. In addition, under the premise of not negatively affecting the application effect of the composition, other sensitizers and/or photoinitiators can also be added to the adhesive for compound use.

According to application needs, one or more macromolecules or polymer compounds can be selectively added to the photocurable adhesive to improve application performance. This macromolecule or polymer compound can be polyol or polyester polyol ; Can also optionally add polymers that do not contain reactive functional groups. These polymers are usually resins containing acidic functional groups such as phenolic hydroxyl groups and carboxyl groups.

In another exemplary embodiment of the present application, a light-curing adhesive is provided, which is formed by polymerization of a light-curing adhesive composition, and the light-curing adhesive composition is any one of the above-mentioned light-curing adhesives. Adhesive composition.

Since the photocurable adhesive composition of the present application selects a specific oxetane compound, a compound having an epoxy group, and a cationic polymerization photoinitiator for use, the adhesion of the formed photocurable adhesive is Curability and adhesion to polarizers and protective films are improved.

In yet another exemplary embodiment of the present application, a polarizing plate is provided, which includes a polarizer and a protective film bonded to the polarizer by an adhesive, and the adhesive is the above-mentioned photocurable adhesive. Since the photocurable adhesive of the present application has good adhesion, acid resistance, alkali resistance, and excellent thermal stability, the polarizing plate using it as the adhesive has a longer service life and better optical performance.

The photocurable adhesive of the present application can be used to bond a protective film on a polarizer formed of a polyvinyl alcohol-based resin film, for example, for a film that is uniaxially stretched and a dichroic dye is oriented by adsorption A protective film is adhered to a polarizer formed of a polyvinyl alcohol-based resin film, and the protective film is bonded to the polarizer in this way to form a polarizer. The protective film may be attached to only one side of the polarizer, or may be attached to both sides of the polarizer. When the protective films are bonded to both sides of the polarizer, each protective film may be a protective film formed of the same type of resin, or may be a protective film formed of a different type of resin.

Based on the above-mentioned application of the present invention, a conventional process in this field can be used to manufacture the polarizing plate. Typically, the manufacturing method includes: laminating a protective film on one or both sides of the polarizer using a photocurable adhesive, and curing the photocurable adhesive by light radiation.

More specific processes can include:

① Coating process: apply the light-curable adhesive on the protective film in an uncured state to form an adhesive coating surface;

②Laminating process: laminating the polarizer on the adhesive coating surface of the protective film;

③Curing process: Use light radiation to cure the photocurable adhesive to form an adhesive layer.

In the production process of the polarizing plate, the protective film can be attached to one side or both sides. Preferably, at least one of the protective films on both sides has other optical functions.

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

In yet another exemplary embodiment of the present application, an optical device is provided, including a polarizing plate, and the polarizing plate is the aforementioned polarizing plate.

When a polarizing plate is used, it can also be an optical member obtained by laminating an optical layer showing an optical function other than the polarizing function on one side. As for the optical member, one or two or more layers selected from the aforementioned reflective layer or semi-transmissive reflective layer, light scattering layer, retardation plate, condensing plate, brightness enhancement film, etc., can be selected according to the purpose of use. The optical layers are combined to form a two-layer or three-layer laminate. The various optical layers forming the optical member are integrated with the polarizing plate by using an adhesive. By arranging the above optical components on one or both sides of the liquid crystal cell, a liquid crystal display device can be made.

The following examples illustrate the present invention in further detail, but they should not be understood as limiting the protection scope of the present invention.

1. Preparation of light-curable adhesive

With reference to the formula shown in the table, the raw materials were mixed uniformly to obtain a photocurable adhesive composition (unless otherwise specified, the listed parts are all by mass).

2. Performance evaluation

The photocurable adhesives prepared in the examples and comparative examples were subjected to defoaming treatment, and they were applied to an 80 μm-thick triacetyl cellulose (TAC) protective film (trade name Fujitech, Fujifilm Corporation) using a bar coater On top, the thickness of the coating film is 10 μm, and then the polyvinyl alcohol-iodine polarizer is bonded together. Next, the same adhesive was applied to the other side of the polarizing plate to a thickness of 10 μm, and a norbornene-based resin film (trade name ZEONOR, OPTES) was bonded to this surface. Then, a mercury lamp (exposure machine model RW-UV20101, accumulatively receiving 2000mJ/cm ² radiation energy) was used for curing.

The adhesion, curing performance and adhesion performance are evaluated. The specific evaluation methods and standards are as follows:

(1) Adhesion

Adhesion is tested with ARCOTEST dyne pens, and the lines are evenly distributed. The largest dyne pen without any bead points within 3 seconds is the dyne test. The smaller the surface dyne value, the greater the surface tension of the attached bottom layer. The more conducive to adhesion.

(2) Adhesion

The adhesiveness of the protective films (that is, TAC film and norbornene film) on both sides was evaluated respectively, and the classification was performed as follows:

A: The protective film cannot be peeled off from the polarizer at the interface. Forcible peeling will cause damage to the film-indicating excellent adhesion;

B: The protective film can be peeled off from the polarizer at the interface without damage to the film-indicating good adhesion;

C: Floating or no adhesion occurs immediately after curing—indicating poor adhesion.

(3) Curability

Peel the TAC film and the norbornene film from the polarizer, and then refer to the GB1728-79 surface drying time measurement method-finger touch method to observe the surface of the cured film and evaluate it according to the following conditions:

A: There is no stickiness-it means good curability;

B: It may be sticky-indicating poor curability.

3. Specific formula and evaluation results

Example 1

Preparation of different compositions in which R is phenyl substituted in component A

A component (see Table 1 for details) 25 parts by mass

Component B1: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanoate 35 parts by mass

B2 component: heated polymerization of glycidyl methacrylate/methyl methacrylate/hydroxyethyl acrylate (mass ratio 30:40:30, Mw is 12000) 35 parts by mass

C component:

5 parts by mass

Table 1

Example	Compound number	n	Dyne	TAC film adhesion	Adhesion of norbornene film	Curability
1-1	1-0	0	32 ++	A	B	B
1-2	1-1	1	32 ++	A	A	A
1-3	1-2	2	32 +	B	A	B
1-4	1-3	3	32 +	B	B	B
1-5	1-4	4	32	B	B	B
1-6	1-5	5	32	C	C	C
1-7	1-6	6	28++	C	C	C
1-8	1-7	7	28+	C	C	C
1-9	1-8	8	28	C	C	C

It can be seen from the results in Table 1 that when n=1, the curing effect is better, the adhesion is good, and the adhesion to the TAC film and the norbornene film is excellent.

Example 2

The preparation of different compositions in which R is biphenyl substituted in component A

Component A (see Table 2 for details) 35 parts by mass

B1 component: 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanoate 25 parts by mass

B2 component: heated polymerization of glycidyl methacrylate/methyl methacrylate/hydroxyethyl acrylate (mass ratio 30:40:30, Mw is 12000) 35 parts by mass

C component:

5 parts by mass

Table 2

Example	Compound number	n	Dyne	TAC film adhesion	Adhesion of norbornene film	Curability
2-1	2-0	0	32 +	B	B	B
2-2	2-1	1	32 ++	A	A	A
2-3	2-2	2	32 +	B	A	B
2-4	2-3	3	32	B	B	B
2-5	2-4	4	32	B	C	C
2-6	2-5	5	28 ++	C	C	C
2-7	2-6	6	28 +	C	C	C
2-8	2-7	7	28 +	C	C	C
2-9	2-8	8	28	C	C	C

It can be seen from the results in Table 2 that when n=1, the curing effect is better, the adhesion is good, and the adhesion to the TAC film and the norbornene film is excellent.

Example 3

Preparation of different compositions in which R is naphthyl substitution in component A

Component A (see Table 3 for details) 40 parts by mass

B1 component: pentaerythritol tetraglycidyl ether 30 parts by mass

B2 component: heat polymerization of glycidyl methacrylate/methyl methacrylate/hydroxyethyl acrylate (mass ratio 30:40:30, Mw is 12000) 25 parts by mass

C component:

5 parts by mass

table 3

Examples/Comparative Examples	Compound number	n	Dyne	TAC film adhesion	Adhesion of norbornene film	Curability
3-1	3-0	0	32 +	B	B	B
3-2	3-1	1	32 ++	A	A	A
3-3	3-2	2	32 +	B	B	B
3-4	3-3	3	32	B	B	C
3-5	3-4	4	32--	B	C	C
3-6	3-5	5	28 ++	C	C	C
3-7	3-6	6	28 +	C	C	C
3-8	3-7	7	28	C	C	C
3-9	3-8	8	28 -	C	C	C

It can be seen from the results in Table 3 that when n=1, the curing effect is better, the adhesion is good, and the adhesion to the TAC film and the norbornene film is excellent.

Select compounds with different n=1, change their weight ratio in the adhesive composition, and evaluate their application performance, see Table 4.

Table 4

table 5

Examples/Comparative Examples	Dyne	TAC film adhesion	Adhesion of norbornene film	Curability
4-1	28 -	B	C	C
4-2	28 -	C	C	C
4-3	28	B	B	B
4-4	28 -	C	C	C
4-5	28 -	C	C	C
4-6	28	B	B	B
4-7	28 -	C	C	C
4-8	28 -	C	C	C
4-9	28 -	C	C	C

From the comprehensive performance evaluation results in Tables 1-3 and 5, it can be seen that the adhesive composition of the present invention has good curing effect, good adhesion, and adhesion to TAC film and norbornene film. Excellent, the reason for analysis may be that the oxetane compound in the composition formula of the present invention is a monofunctional oxygen heterocycle, with moderate viscosity, and the presence of benzyl in the group makes its curing speed faster, thus having excellent Comprehensive application performance.

The foregoing descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc., made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (12)

1. A light-curing adhesive composition, characterized in that it comprises:

   Component A is an oxetane compound with the following structure

   

   Where R represents phenyl, biphenyl, naphthyl, 0≤n≤4;

   Component B: It is a compound with epoxy group;

   Component C: Cationic polymerization photoinitiator.
2. The light-curing adhesive composition according to claim 1, wherein the component A is

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

   Component B1: polyglycidyl ether of a polyhydric alcohol with 2-10 carbon atoms;

   Component B2: It is a polymer with epoxy groups.
4. The light-curing adhesive composition according to claim 3, wherein the component B1 is selected from the group consisting of ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol two Glycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, dimethylol cyclohexane diglycidyl ether, 1,9-nonanediol diglycidyl ether Glyceryl ether, diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, hydroquinone diglycidyl ether, resorcinol diglycidyl ether, trimethylolpropane triglycidyl ether , Pentaerythritol tri- or tetra-glycidyl ether, and isocyanuric acid ethylene oxide adduct di- or tri-glycidyl ether of any one or more of the group consisting of.
5. The light-curing adhesive composition according to claim 3, wherein the Tg of the component B2 is greater than or equal to 20°C, and the Mw is 1,000 to 30,000, preferably 3,000 to 20,000, more preferably 5,000 to 15,000, Here, Mw refers to the weight average molecular weight obtained by converting the molecular weight measured by GPC into polystyrene.
6. The light-curing adhesive composition according to claim 3, wherein the component B2 is formed by polymerizing monomer b1, monomer b2 and optional monomer b3, wherein said 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 the monomer b1 is preferably glycidyl acrylate, glycidyl methacrylate, 3,4- Epoxy cyclohexyl acrylate or 3,4-epoxycyclohexyl methacrylate; the monomer b2 is a monofunctional methacrylate having 1 to 10 carbon atoms, preferably the monomer b2 is selected from Methyl acrylate, 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, Any one or more of the group consisting of decyl methacrylate, isodecyl methacrylate and benzyl methacrylate; the monomer b3 is an alkenyl compound different from the monomer b1, and preferably contains Any one of the group consisting of an aromatic group-containing vinyl compound, monofunctional acrylate, acrylonitrile, methacrylonitrile, acrylamide, and methacrylamide, and the aromatic group-containing vinyl compound is Styrene or α-methylstyrene, the monofunctional acrylate is selected from methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, acrylic acid Isobutyl, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, isooctyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, isodecyl acrylate, and benzyl acrylate Any one or more of the group consisting of esters.
7. The light-curing adhesive composition according to claim 6, wherein the component B2 comprises 10-60% monomer b1, 10-70% monomer b2 and 0-70% by weight percentage. 60% monomer b3.
8. The light-curing adhesive composition according to claim 1, wherein the component C is selected from one or more of the group consisting of iodonium salt, sulfonium salt, and aryl ferrocene salt combination.
9. The photocurable adhesive composition according to any one of claims 2 to 8, wherein the weight content of the component A is 25 to 55 based on the photocurable adhesive composition. %, preferably 25-45%; 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 light-curing adhesive formed by polymerization of a light-curing adhesive composition, characterized in that the light-curing adhesive composition is the light-curing adhesive according to any one of claims 1 to 9剂组合物。 Agent composition.
11. A polarizing plate, comprising a polarizer and a protective film bonded on the polarizer by an adhesive, wherein the adhesive is the light-curing adhesive according to claim 10.
12. An optical device, comprising a polarizing plate, wherein the polarizing plate is the polarizing plate of claim 11.