Adhesive composition, adhesive layer, and optical member with adhesive layer

Abstract

The present invention provides an adhesive composition comprising 30-60 parts by mass of an epoxy-modified silicone resin, 20-60 parts by mass of an epoxy monomer, and 0.1-5 parts by mass of a cationic photoinitiator, characterized in that the epoxy monomer comprises a composition of a three-membered epoxy monomer and a four-membered epoxy monomer, which has excellent durability.

Description

Technical Field

[0001] This invention relates to an adhesive composition. More specifically, it relates to an adhesive composition that exhibits excellent adhesive properties after a crosslinking reaction, particularly excellent durability even when the adhesive layer is thinned. Furthermore, it relates to an adhesive layer formed using the said adhesive composition and a method for manufacturing the same. Moreover, it relates to an optical component with the adhesive layer and an image display device using the same. Background Technology

[0002] For adhesive compositions used in adhesive layers for bonding optical components, durability is required. That is, adhesive layers bonded to optical components, installed in image display devices, etc., are sometimes placed in high-temperature or high-temperature-high-humidity environments, and sometimes in environments with repeated high-temperature and low-temperature cycles. It is necessary to suppress potential dimensional changes in the adhesive layer that may occur alongside adjacent optical components, even under such conditions. As a result, problems include buoyancy and peeling at the interface between the adhesive layer and its adjacent optical components, and foaming of the adhesive layer.

[0003] However, conventional adhesive compositions sometimes lack durability when bonded to optical components as adhesive layers. In particular, the durability is insufficient when the surface of the optical component to which the adhesive layer is bonded is difficult to activate effectively even through surface activation treatments such as corona treatment.

[0004] The object of the present invention is to provide an adhesive composition that exhibits good durability when bonded to an optical component as an adhesive layer, even if the surface of the optical component is difficult to activate effectively through surface activation treatment; an adhesive layer comprising the adhesive composition; and an optical component having the adhesive layer. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide an adhesive with good durability.

[0006] According to one aspect of the present invention, a photocurable adhesive composition is provided, the photocurable adhesive composition comprising, based on its total solids content:

[0007] 30-60 parts by weight of epoxy-modified silicone resin;

[0008] 20-60 parts by weight of epoxy monomers: wherein the ratio of ternary epoxy monomers to quaternary epoxy monomers is 1-1.5:1.5:1;

[0009] 0.1-5 parts by weight of cationic photoinitiator.

[0010] Furthermore, the epoxy-modified organosilicon resin is a compound in which one or more oxobutyric groups are grafted onto the side chains of at least one repeating unit in an organosilicon resin.

[0011] Furthermore, the epoxy monomer is a three-membered epoxy or an oxobutane compound;

[0012] Further, the ternary epoxy monomer is preferably an epoxy compound having an epoxy cyclohexyl group, such as 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, ε-caprolactone-modified-3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, bis((3,4-epoxycyclohexyl)methyl)adipic acid ester, epoxycyclohexane, 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane, 3,4-epoxycyclohexylmethyl methacrylate, 3,4 - Polymers of cyclohexyl methacrylate, 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexane carboxylate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate and caprolactone, 4-methyl-1,2-epoxycyclohexane, 2,2-bis(3,3'-epoxycyclohexyl)propane, and 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane.

[0013] Furthermore, the oxetane monomer is a compound having at least one hydroxyl group and at least one oxetane group.

[0014] Furthermore, the cationic photoinitiator is selected from one or more combinations of iodonium salts and thiodonium salts;

[0015] Furthermore, the cationic photoinitiator is preferably a commercially available cationic photoinitiator, such as (but not limited to) products with trade names PAG20001, PAG20002, PAG30201, and PAG30101 (produced by Changzhou Qiangli Electronic New Materials Co., Ltd.), and Irgacure250 produced by BASF in Germany.

[0016] In addition to the components described above, depending on the application environment of the product, the adhesive composition of the present invention may selectively add commonly used organic and / or inorganic additives in the art, including (but not limited to) leveling agents, dispersants, curing agents, surfactants, defoamers, storage enhancers, etc., which are easily determined by those skilled in the art. The total content of additives is 0-5% by weight, preferably 0-3%.

[0017] Furthermore, the adhesive composition described in this invention can be applied to various applications such as structural adhesives, sealants, optical adhesives, glass adhesives, pressure-sensitive adhesives, release agents, and conductive adhesives. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] (1) Preparation of adhesive composition

[0020] Referring to the formulation shown in Table 1, mix the raw materials thoroughly to obtain a light-curing adhesive composition (unless otherwise specified, all parts listed are parts by weight):

[0021] Table 1

[0022]

[0023]

[0024] (2) Fabrication of the adhesive layer

[0025] The photocurable adhesive obtained in the examples was degassed and then coated onto an 80 μm thick triacetyl cellulose (TAC) protective film (trade name Fujitech, Fujifilm Corporation) using a rod coater, resulting in a coating thickness of 10 μm. This film was then bonded to a polyvinyl alcohol-iodine polarizer. Next, the same adhesive was coated onto the other side of the polarizer, resulting in a coating thickness of 10 μm, and a norbornene resin film (trade name ZEONOR, OPTES Corporation) was bonded to this side. Finally, curing was performed using a mercury lamp (exposure machine model RW-UV20101, accumulating 2000 mJ / cm² of radiation energy).

[0026] (3) Performance evaluation---durability test

[0027] The polarizer coated with the adhesive layer obtained above was tested under the following conditions:

[0028] A: Heat resistance test under dry conditions at 80℃ for 1000 hours;

[0029] B: Damp heat resistance test for 1000 hours at 60℃ and 90% relative humidity;

[0030] C: The thermal shock (HS) test is performed for 500 cycles, with one cycle consisting of maintaining the product under dry conditions at 70°C for 30 minutes and then under dry conditions at -40°C for 30 minutes.

[0031] Visually inspect the samples after each test and evaluate their durability according to the following evaluation criteria. The results are shown in Table 2.

[0032] ◎: No visible changes in appearance such as floating, peeling, or foaming are observed;

[0033] ○: There are basically no visible changes in appearance such as floating, peeling, or foaming;

[0034] ●: Observe more changes in appearance such as floating, peeling, and foaming;

[0035] ▲: Obvious changes in appearance, such as floating, peeling, and foaming, are clearly visible;

[0036] Table 2

[0037]

[0038] The adhesive composition provided by this invention exhibits excellent durability under various conditions and has strong application prospects.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A photocurable adhesive composition comprising: 30-60 parts by weight of epoxy-modified silicone resin, 20-60 parts by weight of epoxy monomer, and 0.1-5 parts by weight of cationic photoinitiator, characterized in that... The epoxy monomers comprise a combination of ternary epoxy monomers and quaternary epoxy monomers.

2. The adhesive composition according to claim 1, characterized in that... The ratio of ternary epoxy monomers to quaternary epoxy monomers in the epoxy monomers is 1-1.5:1.5:

1.

3. The adhesive composition according to claim 1, characterized in that... The epoxy-modified silicone resin is a compound in which one or more oxobutyric groups are grafted onto the side chains of at least one repeating unit of a silicone resin.

4. The adhesive composition according to claim 1 or 2, characterized in that... The ternary epoxy monomer is an epoxy compound containing an epoxy cyclohexyl group.

5. The adhesive composition according to claim 1 or 2, characterized in that... A four-membered epoxy monomer is a compound having at least one hydroxyl group and at least one oxobutyric group.

6. The adhesive composition according to claim 1, characterized in that... The cationic photoinitiator is selected from one or more combinations of iodonium salts and thiodonium salts.

7. The adhesive composition according to claim 1 or 6, characterized in that... The cationic photoinitiators are products with trade names PAG20001, PAG20002, PAG30201, and PAG30101 (produced by Changzhou Qiangli Electronic New Materials Co., Ltd.), and Irgacure250 produced by BASF GmbH in Germany.

8. An adhesive composition used in structural adhesives, sealants, optical adhesives, glass adhesives, pressure-sensitive adhesives, release agents, and conductive adhesives.

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