Epoxy resin type uv debonding adhesive and preparation method thereof

Abstract

This invention relates to an epoxy resin-based UV anti-tack adhesive and its preparation method, belonging to the field of new materials technology. The epoxy resin-based UV anti-tack adhesive of this invention is used in wafer manufacturing. The preparation steps are as follows: (1) Using terminal carboxyl dicarboxylic acid and 1,6-hexanediol diglycidyl ether as raw materials, a prepolymer with epoxy groups at both ends is synthesized; (2) The prepolymer is reacted with 4,4-diaminodiphenylmethane to obtain an epoxy resin-based adhesive; (3) A photoinitiator is added to obtain an epoxy resin-based UV anti-tack adhesive that can be rapidly cured in 30 minutes. The epoxy resin-based UV anti-tack adhesive of this invention has a curing time of only 30 minutes. Before UV irradiation, the 180° peel strength can reach 19.86~30.69N / 25mm, and after UV irradiation, the 180° peel strength is 0.04~0.85N / 25mm, with a significant anti-tack effect and achieving residue-free peeling.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology and relates to UV anti-tack adhesive (adhesive) technology in wafer manufacturing, specifically to a fast-curing epoxy resin-based UV anti-tack adhesive and its preparation method. Background Technology

[0002] With the rapid development of technologies such as 5G, artificial intelligence, and the internet, electronic devices are moving towards miniaturization and multifunctionality. This trend has driven the demand for thinner and smaller chips, posing significant challenges to the wafer manufacturing industry. During the cutting and grinding of wafer materials, the inherent brittleness of wafers makes them prone to warping and movement, leading to processing difficulties. UV-resistant adhesives possess high bonding strength during processing, firmly securing the wafer. After processing, UV irradiation rapidly reduces the adhesive strength, leaving minimal residue after peeling. To adapt to the pace of large-scale wafer production, the curing time for the adhesive to reach usable bonding strength needs to be significantly shortened, while simultaneously achieving excellent anti-tack performance and low residue after UV irradiation.

[0003] UV-reducing adhesives are adhesives that reduce or eliminate bond strength under ultraviolet (UV) light. They possess high tack under normal conditions, but their tack decreases dramatically after UV exposure, achieving a reversible or temporary bond. This property makes them uniquely advantageous in applications requiring temporary fixation, protection, or assembly.

[0004] Currently, UV adhesives on the market are mainly divided into two categories: acrylate-based and polyurethane-based. Both have insurmountable technical defects. Acrylate-based adhesives are prepared using acrylate as the core monomer, combined with multifunctional crosslinking monomers and conventional photoinitiators. These adhesives tend to leave residue on the wafer surface after UV irradiation, which directly affects subsequent chip packaging and electrical performance. Furthermore, their 180° peel strength before UV irradiation is low, generally below 15 N / 25 mm, failing to achieve firm fixation during wafer processing and easily leading to a decrease in wafer yield. Polyurethane-based adhesives solve the 180° peel strength problem of acrylate-based adhesives, achieving higher adhesive strength before UV irradiation. However, the drawback of this type of adhesive is its excessively long curing time; reaching the required 180° peel strength requires at least 12 hours, extending the wafer processing cycle and reducing production efficiency. Currently, the application of dicarboxylic acids such as itaconic acid, citraconic acid, and fumaric acid in the reaction with binary epoxy resins in the preparation system of UV adhesives has not yet been explored in this field. Summary of the Invention

[0005] To further improve the tack reduction effect of existing UV tack reducers and solve the problem of excessively long curing time for polyurethane-based UV tack reducers to reach the required peel strength before UV irradiation, this invention provides an epoxy resin-based UV tack reducer that achieves rapid curing, and also provides a method for preparing the epoxy resin-based UV tack reducer.

[0006] The structural formula of an epoxy resin-based UV-resistant adhesive is as follows:

[0007] ;

[0008] Where R1 is , or One of them;

[0009] R2 is ;

[0010] R3 is .

[0011] The epoxy resin-based UV-resistant adhesive achieves usable bond strength in a curing time of only 30 minutes. Before UV irradiation, the 180° peel strength is 19.86–30.69 N / 25 mm, and after UV irradiation, the 180° peel strength is 0.04–0.85 N / 25 mm.

[0012] The preparation steps of an epoxy resin-based UV anti-tack adhesive are as follows:

[0013] (1) A carboxyl-terminated dicarboxylic acid and 1,6-hexanediol diglycidyl ether were dissolved in solvent A at a molar ratio of 1:1.1 to 1:1.9. The reactants were synthesized under the action of catalyst A and polymerization inhibitor. Hexane was added to the reactants and stirred to precipitate the product. The product was then added to deionized water for further precipitation and drying to obtain a prepolymer with epoxy groups at both ends. The structure is as follows:

[0014]

[0015] The degree of polymerization n in the formula ranges from 2 to 11;

[0016] The prepolymer has an epoxy value of 0.0466–0.1892 mol / 100g and a molecular weight of 1060–4290.

[0017] The terminal carboxyl dicarboxylic acid mentioned is one of itaconic acid, citraconic acid, and fumaric acid;

[0018] Solvent A is one of toluene, xylene, and N,N-dimethylformamide, and the amount of solvent used is 10-30 mL;

[0019] Catalyst A is one of aluminum acetylacetonate, zinc acetylacetonate, and 2,4,6-tris(dimethylaminomethyl)phenol, and the amount added is 0.5% to 2% of the sum of the mass of the terminal carboxyl dicarboxylic acid and 1,6-hexanediol diglycidyl ether.

[0020] The polymerization inhibitor is one of hydroquinone and 2,6-di-tert-butyl-p-cresol, and the amount added is 1% of the mass of the terminal carboxyl dicarboxylic acid;

[0021] (2) The prepolymer and 4,4-diaminodiphenylmethane monomer were dissolved in solvent B at a molar ratio of 2.2:1 to 1.8:1 and reacted under the action of catalyst B and polymerization inhibitor to obtain epoxy resin-based adhesive.

[0022] Solvent B is one of ethyl acetate, xylene, and N,N-dimethylformamide, and the amount of solvent used is 10-30 mL.

[0023] The catalyst B is 2,4,6-tris(dimethylaminomethyl)phenol, and the amount added is 0.5% to 2% of the sum of the mass of the prepolymer and 4,4-diaminodiphenylmethane.

[0024] The polymerization inhibitor is one of hydroquinone and 2,6-di-tert-butyl-p-cresol, and the amount added is 1% of the sum of the mass of the prepolymer and 4,4-diaminodiphenylmethane;

[0025] (3) Cool the epoxy resin base adhesive to room temperature, add a photoinitiator to the epoxy resin base adhesive, stir for 1 hour, and obtain epoxy resin type UV anti-tack adhesive.

[0026] The photoinitiator is one or more of diphenyl (2,4,6-trimethylphenylformyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylphenyl ketone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone; the amount of photoinitiator added is 1 to 5% of the mass of the epoxy resin-based adhesive.

[0027] Further technical solutions are as follows:

[0028] In step (1), the reaction conditions are: under a nitrogen atmosphere, at a temperature of 110-140°C, and for a reaction time of 3-5 hours.

[0029] In step (1), the precipitation conditions are as follows: the prepolymer is precipitated three times in sequence using n-hexane and deionized water at 80°C.

[0030] In step (1), the vacuum drying conditions are: vacuum degree of -85kPa, drying temperature of 50~60℃, and drying time of 12~24h.

[0031] In step (2), the reaction conditions are: under a nitrogen atmosphere, at a temperature of 80-100℃, for a reaction time of 3-5 hours.

[0032] The beneficial technical effects of this invention are reflected in the following aspects:

[0033] (1) The inventiveness of the epoxy resin type UV anti-tack adhesive of the present invention

[0034] The prepolymer with epoxy groups at both ends prepared in this invention is produced by reacting terminal carboxyl dicarboxylic acid with a high double bond content with terminal epoxy diepoxide monomers. Therefore, the prepared UV anti-tack adhesive has a high double bond content, resulting in dense reaction sites during UV curing and rapid formation of a dense cross-linked network. Simultaneously, the UV-induced double bond cross-linking reaction causes volume shrinkage of the adhesive film and the formation of wrinkled structures on its surface. These wrinkled structures significantly reduce the effective contact area between the adhesive film and the silicon wafer, leading to a significant decrease in adhesion. This results in an epoxy resin-based UV anti-tack adhesive with a 180° peel strength of 19.86–30.69 N / 25 mm before UV irradiation; after UV irradiation, its 180° peel strength drops to as low as 0.04–0.85 N / 25 mm, with low residual adhesive content and excellent anti-tack effect. Furthermore, the curing time for this anti-tack adhesive to reach the required bonding strength before UV irradiation is significantly shortened to 30 minutes, meeting the high-strength wafer fixation requirements.

[0035] (2) The inventiveness of the preparation method of the present invention

[0036] In step (1) of this invention, the prepolymer backbone prepared by reacting terminal carboxyl dicarboxylic acid with terminal epoxy diepoxide monomers contains a large number of polar groups such as ester groups and hydroxyl groups. A high-density intermolecular hydrogen bond network can be formed between hydroxyl groups and ester groups, and between hydroxyl groups themselves, effectively improving the adhesive strength of the obtained UV anti-tack adhesive. Simultaneously, the highly reactive epoxy groups introduced into the system can rapidly crosslink with the amino groups in the terminal amino diamine under mild conditions, forming a stable crosslinking network without long-term standing, allowing the anti-tack adhesive to reach its usable strength within 30 minutes. The preparation process of the epoxy resin-type UV anti-tack adhesive of this invention does not require the addition of small molecule reactive diluents, the production process is simple, and it can be used for large-scale production. Attached Figure Description

[0037] Figure 1 The infrared spectrum of the itaconic acid-1,6-hexanediol diglycidyl ether prepolymer with epoxy groups at both ends prepared in Example 1.

[0038] Figure 2 The 180° peel strength-displacement curves of the epoxy resin-type UV-resistant adhesive prepared in Example 1 before and after UV irradiation. Detailed Implementation

[0039] The present invention will now be described in detail through specific embodiments.

[0040] Unless otherwise defined, all technical and scientific terms used in this invention are consistent with the prior art known to those skilled in the art and the description of this invention. This invention may also be implemented using any prior art methods, devices and materials that are similar to or equivalent to the methods, devices and materials in the embodiments of this invention.

[0041] Example 1

[0042] The preparation procedure for an epoxy resin-based UV-resistant adhesive is as follows:

[0043] (1) Preparation of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer with epoxy groups at both ends

[0044] 15.29 g itaconic acid, 40.60 g 1,6-hexanediol diglycidyl ether monomer, 0.85 g aluminum acetylacetonate and 0.15 g 2,6-di-tert-butyl-p-cresol were added to 30 mL xylene, and the mixture was purged with nitrogen in a 250 mL single-necked flask and reacted at 120 °C for 3 h to obtain the reaction product.

[0045] Add 300 mL of n-hexane to the reaction product and stir for 5 min to precipitate. Then add 500 mL of deionized water to precipitate again, obtaining the precipitate. Dry the precipitate in a vacuum oven at 55 °C for 14 h to obtain a prepolymer with epoxy groups at both ends, namely itaconic acid-1,6-hexanediol diglycidyl ether prepolymer, with the following structural formula:

[0046]

[0047] The degree of polymerization n in the formula is 8. The epoxy value of the obtained itaconic acid-1,6-hexanediol diglycidyl ether prepolymer is 0.0660 mol / 100g, and the molecular weight is 3030.

[0048] The molar ratio of itaconic acid to 1,6-hexanediol diglycidyl ether is 1:1.5.

[0049] The catalyst aluminum acetylacetonate was added at a rate of 1.5% of the sum of the masses of itaconic acid and 1,6-hexanediol diglycidyl ether.

[0050] The amount of polymerization inhibitor 2,6-di-tert-butyl-p-cresol added is 1% of the mass of itaconic acid.

[0051] See Figure 1 Itaconic acid-1,6-hexanediol diglycidyl ether prepolymer at 1635 cm⁻¹ -1 A stretching vibration peak of the C=C double bond appears at 1735 cm⁻¹. -1 A stretching vibration peak of C=O in the ester bond appears at 3500 cm⁻¹.-1 The stretching vibration peak of OH appears at 910 cm⁻¹; -1 The presence of characteristic peaks of epoxy indicates the successful synthesis of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer with epoxy groups at both ends.

[0052] (2) Preparation of epoxy resin-based adhesive

[0053] 13.93g of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 0.41g of 4,4-diaminodiphenylmethane monomer were dissolved in 15.9ml of ethyl acetate. 0.14g of 2,4,6-tris(dimethylaminomethyl)phenol and 0.14g of 2,6-di-tert-butyl-p-cresol were added, nitrogen gas was introduced, and the reaction was carried out at 90℃ for 3h to obtain epoxy resin-based adhesive.

[0054] The molar ratio of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer to 4,4-diaminodiphenylmethane is 2.2:1;

[0055] The amount of catalyst 2,4,6-tris(dimethylaminomethyl)phenol added is 1% of the sum of the mass of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0056] The amount of polymerization inhibitor 2,6-di-tert-butyl-p-cresol added is 1% of the sum of the mass of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0057] (3) Preparation of epoxy resin type UV anti-tack adhesive

[0058] The epoxy resin-based adhesive was cooled to room temperature, and 0.43 g of ethyl 2,4,6-trimethylbenzoylphenylphosphonate was added to the epoxy resin-based adhesive. The mixture was stirred for 1 h to obtain an epoxy resin-based UV anti-tack adhesive.

[0059] The amount of photoinitiator added is 3% of the mass of the epoxy resin-based adhesive.

[0060] The structural formula of the epoxy resin-based UV anti-tack adhesive prepared in Example 1 is as follows:

[0061] ;

[0062] Where R1 is ;

[0063] R2 is ;

[0064] R3 is .

[0065] See Figure 2The peel strength at 180° before UV irradiation was 27.74 N / 25 mm, and the peel strength at 180° after UV irradiation was 0.04 N / 25 mm.

[0066] Example 2

[0067] The preparation procedure for an epoxy resin-based UV-resistant adhesive is as follows:

[0068] (1) Preparation of citraconic acid-1,6-hexanediol diglycidyl ether prepolymer with epoxy groups at both ends

[0069] 10.08 g citraconic acid, 23.20 g 1,6-hexanediol diglycidyl ether monomer, 0.67 g aluminum acetylacetonate and 0.11 g 2,6-di-tert-butyl-p-cresol were added to 10 mL xylene, and the mixture was reacted in a 250 mL single-necked flask under nitrogen atmosphere at 110 °C for 5 h to obtain the reaction product.

[0070] The reaction product was added to 300 mL of n-hexane and stirred for 5 min to precipitate. Then, it was added to 500 mL of deionized water for further precipitation to obtain the precipitate. The precipitate was dried in a vacuum oven at 55 °C for 20 h to obtain a prepolymer with epoxy groups at both ends, namely citralic acid-1,6-hexanediol diglycidyl ether prepolymer, with the following structural formula:

[0071]

[0072] The degree of polymerization n in the formula is 11. The epoxy value of the obtained citralic acid-1,6-hexanediol diglycidyl ether prepolymer is 0.04660 mol / 100g, and the molecular weight is 4290.

[0073] The molar ratio of citralic acid to 1,6-hexanediol diglycidyl ether is 1:1.3.

[0074] The catalyst aluminum acetylacetonate was added at 2% of the sum of the masses of citralic acid and 1,6-hexanediol diglycidyl ether.

[0075] The amount of polymerization inhibitor 2,6-di-tert-butyl-p-cresol added is 1% of the mass of citralic acid.

[0076] (2) Preparation of epoxy resin-based adhesive

[0077] 13.95g of citralic acid-1,6-hexanediol diglycidyl ether prepolymer and 0.32g of 4,4-diaminodiphenylmethane monomer were dissolved in 15.8ml of ethyl acetate. 0.28g of 2,4,6-tris(dimethylaminomethyl)phenol and 0.14g of 2,6-di-tert-butyl-p-cresol were added, nitrogen gas was introduced, and the reaction was carried out at 90℃ for 3h to obtain epoxy resin-based adhesive.

[0078] The molar ratio of citralic acid-1,6-hexanediol diglycidyl ether prepolymer to 4,4-diaminodiphenylmethane is 2.0:1.

[0079] The amount of catalyst 2,4,6-tris(dimethylaminomethyl)phenol added is 2% of the sum of the mass of citralic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0080] The amount of polymerization inhibitor 2,6-di-tert-butyl-p-cresol added is 1% of the sum of the mass of citralic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0081] (3) Preparation of epoxy resin type UV anti-tack adhesive

[0082] The epoxy resin base was cooled to room temperature, and 0.28 g of 1-hydroxycyclohexylphenyl ketone was added to the epoxy resin base. The mixture was stirred for 1 h to obtain an epoxy resin-based UV anti-tack adhesive.

[0083] The amount of photoinitiator added is 2% of the mass of the epoxy resin-based adhesive.

[0084] The structural formula of the epoxy resin-based UV anti-tack adhesive prepared in Example 2 is as follows:

[0085] ;

[0086] Where R1 is ;

[0087] R2 is ;

[0088] R3 is .

[0089] The peel strength at 180° before UV irradiation was 25.34 N / 25 mm, and the peel strength at 180° after UV irradiation was 0.85 N / 25 mm.

[0090] Example 3

[0091] The preparation procedure for an epoxy resin-based UV-resistant adhesive is as follows:

[0092] (1) Preparation of fumaric acid-1,6-hexanediol diglycidyl ether prepolymer with epoxy groups at both ends

[0093] 10.98 g of fumaric acid, 23.96 g of 1,6-hexanediol diglycidyl ether monomer, 0.17 g of aluminum acetylacetonate and 0.11 g of hydroquinone were added to 20 mL of xylene, and the mixture was purged with nitrogen in a 250 mL single-necked flask and reacted at 120 °C for 4 h to obtain the reaction product.

[0094] The reaction product was added to 300 mL of n-hexane and stirred for 5 min to precipitate. Then, it was added to 500 mL of deionized water for further precipitation to obtain the precipitate. The precipitate was dried in a vacuum oven at 55 °C for 12 h to obtain a prepolymer with epoxy groups at both ends, namely, fumaric acid-1,6-hexanediol diglycidyl ether prepolymer, with the following structural formula:

[0095]

[0096] The degree of polymerization n in the formula is 9. The epoxy value of the obtained fumaric acid-1,6-hexanediol diglycidyl ether prepolymer is 0.0569 mol / 100g, and the molecular weight is 3510.

[0097] The molar ratio of trans-butenedioic acid to 1,6-hexanediol diglycidyl ether is 1:1.1.

[0098] The amount of catalyst aluminum acetylacetonate added is 0.5% of the sum of the masses of fumaric acid and 1,6-hexanediol diglycidyl ether;

[0099] The amount of hydroquinone, the polymerization inhibitor, added is 1% of the mass of fumaric acid.

[0100] (2) Preparation of epoxy resin-based adhesive

[0101] 11.82 g of fumaric acid-1,6-hexanediol diglycidyl ether prepolymer and 0.31 g of 4,4-diaminodiphenylmethane monomer were dissolved in 13.5 ml of ethyl acetate. 0.06 g of 2,4,6-tris(dimethylaminomethyl)phenol and 0.12 g of hydroquinone were added, nitrogen gas was introduced, and the mixture was reacted at 80 °C for 4 h to obtain epoxy resin-based adhesive.

[0102] The molar ratio of trans-butenedioic acid-1,6-hexanediol diglycidyl ether prepolymer to 4,4-diaminodiphenylmethane is 2.2:1;

[0103] The amount of catalyst 2,4,6-tris(dimethylaminomethyl)phenol added is 0.5% of the sum of the mass of fumaric acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0104] The amount of hydroquinone added as the polymerization inhibitor is 1% of the sum of the mass of the prepolymer of fumaric acid-1,6-hexanediol diglycidyl ether and 4,4-diaminodiphenylmethane.

[0105] (3) Preparation of epoxy resin type UV anti-tack adhesive

[0106] The epoxy resin base was cooled to room temperature, and 0.61g of 2-hydroxy-2-methyl-1-phenyl-1-propanone was added to the epoxy resin base. The mixture was stirred for 1 hour to obtain an epoxy resin-based UV anti-tack adhesive.

[0107] The amount of photoinitiator added is 5% of the mass of the epoxy resin-based adhesive.

[0108] The structural formula of the epoxy resin-based UV anti-tack adhesive prepared in Example 3 is as follows:

[0109] ;

[0110] Where R1 is ;

[0111] R2 is ;

[0112] R3 is .

[0113] The peel strength at 180° before UV irradiation was 19.86 N / 25 mm, and the peel strength at 180° after UV irradiation was 0.25 N / 25 mm.

[0114] Example 4

[0115] The preparation procedure for an epoxy resin-based UV-resistant adhesive is as follows:

[0116] (1) Preparation of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer with epoxy groups at both ends

[0117] 10.96 g itaconic acid, 36.86 g 1,6-hexanediol diglycidyl ether monomer, 0.71 g zinc acetylacetone and 0.10 g hydroquinone were added to 30 mL toluene, and the mixture was purged with nitrogen in a 250 mL single-necked flask and reacted at 120 °C for 3 h to obtain the reaction product.

[0118] The reaction product was added to 300 mL of n-hexane and stirred for 5 min to precipitate. Then, it was added to 500 mL of deionized water for further precipitation to obtain the precipitate. The precipitate was dried in a vacuum oven at 50 °C for 24 h to obtain a prepolymer with epoxy groups at both ends, namely itaconic acid-1,6-hexanediol diglycidyl ether prepolymer, with the following structural formula:

[0119]

[0120] The degree of polymerization n in the formula is 2. The epoxy value of the obtained itaconic acid-1,6-hexanediol diglycidyl ether prepolymer is 0.1892 mol / 100g, and the molecular weight is 1060.

[0121] The molar ratio of itaconic acid to 1,6-hexanediol diglycidyl ether is 1:1.9.

[0122] The amount of catalyst zinc acetylacetone added is 1.5% of the sum of the masses of itaconic acid and 1,6-hexanediol diglycidyl ether;

[0123] The amount of hydroquinone, the polymerization inhibitor, added is 1% of the mass of itaconic acid.

[0124] (2) Preparation of epoxy resin-based adhesive

[0125] 14.29 g of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 1.21 g of 4,4-diaminodiphenylmethane monomer were dissolved in 17.2 ml of ethyl acetate. 0.31 g of 2,4,6-tris(dimethylaminomethyl)phenol and 0.15 g of hydroquinone were added, nitrogen gas was introduced, and the mixture was reacted at 80 °C for 5 h to obtain epoxy resin-based adhesive.

[0126] The molar ratio of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer to 4,4-diaminodiphenylmethane is 2.2:1;

[0127] The amount of catalyst 2,4,6-tris(dimethylaminomethyl)phenol added is 2% of the sum of the mass of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0128] The amount of hydroquinone added as the polymerization inhibitor is 1% of the sum of the mass of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0129] (3) Preparation of epoxy resin type UV anti-tack adhesive

[0130] The epoxy resin-based adhesive was cooled to room temperature, and 0.62 g of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the epoxy resin-based adhesive. The mixture was stirred for 1 h to obtain an epoxy resin-based UV anti-tack adhesive.

[0131] The amount of photoinitiator added is 4% of the mass of the epoxy resin-based adhesive.

[0132] The structural formula of the epoxy resin-based UV anti-tack adhesive prepared in Example 4 is as follows:

[0133] ;

[0134] Where R1 is ;

[0135] R2 is ;

[0136] R3 is .

[0137] The peel strength at 180° before UV irradiation was 30.69 N / 25 mm, and the peel strength at 180° after UV irradiation was 0.18 N / 25 mm.

[0138] Example 5

[0139] The preparation procedure for an epoxy resin-based UV-resistant adhesive is as follows:

[0140] (1) Preparation of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer with epoxy groups at both ends

[0141] 15.83 g itaconic acid, 47.64 g 1,6-hexanediol diglycidyl ether monomer, 0.95 g 2,4,6-tris(dimethylaminomethyl)phenol and 0.16 g hydroquinone were added to 30 mL N,N-dimethylformamide, and the mixture was reacted in a 250 mL single-necked flask under nitrogen atmosphere at 140 °C for 3 h to obtain the reaction product.

[0142] The reaction product was added to 300 mL of n-hexane and stirred for 5 min to precipitate. Then, it was added to 500 mL of deionized water for further precipitation to obtain the precipitate. The precipitate was dried in a vacuum oven at 60 °C for 12 h to obtain a prepolymer with epoxy groups at both ends, namely itaconic acid-1,6-hexanediol diglycidyl ether prepolymer, with the following structural formula:

[0143]

[0144] The degree of polymerization n in the formula is 3. The epoxy value of the obtained itaconic acid-1,6-hexanediol diglycidyl ether prepolymer is 0.1382 mol / 100g, and the molecular weight is 1447.

[0145] The molar ratio of itaconic acid to 1,6-hexanediol diglycidyl ether is 1:1.7.

[0146] The catalyst 2,4,6-tris(dimethylaminomethyl)phenol was added at a rate of 1.5% of the sum of the masses of itaconic acid and 1,6-hexanediol diglycidyl ether.

[0147] The amount of hydroquinone, the polymerization inhibitor, added is 1% of the mass of itaconic acid.

[0148] (2) Preparation of epoxy resin-based adhesive

[0149] 13.75g of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 1.04g of 4,4-diaminodiphenylmethane monomer were dissolved in 16.4ml of ethyl acetate. 0.074g of 2,4,6-tris(dimethylaminomethyl)phenol and 0.14g of hydroquinone were added. Nitrogen gas was introduced, and the mixture was reacted at 100℃ for 3h to obtain epoxy resin-based adhesive.

[0150] The molar ratio of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer to 4,4-diaminodiphenylmethane is 1.8:1.

[0151] The amount of catalyst 2,4,6-tris(dimethylaminomethyl)phenol added is 0.5% of the sum of the mass of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0152] The amount of hydroquinone added as the polymerization inhibitor is 1% of the sum of the mass of itaconic acid-1,6-hexanediol diglycidyl ether prepolymer and 4,4-diaminodiphenylmethane.

[0153] (3) Preparation of epoxy resin type UV anti-tack adhesive

[0154] The epoxy resin-based adhesive was cooled to room temperature, and 0.15g of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was added to the epoxy resin-based adhesive. The mixture was stirred for 1 hour to obtain an epoxy resin-based UV anti-tack adhesive.

[0155] The amount of photoinitiator added is 1% of the mass of the epoxy resin-based adhesive.

[0156] The structural formula of the epoxy resin-based UV anti-tack adhesive prepared in Example 5 is as follows:

[0157] ;

[0158] Where R1 is ;

[0159] R2 is ;

[0160] R3 is .

[0161] The peel strength at 180° before UV irradiation was 29.57 N / 25 mm, and the peel strength at 180° after UV irradiation was 0.74 N / 25 mm.

[0162] Performance testing

[0163] Using GB / T2792-1998 as the test standard, the sample width was 25 mm, the length was 100 mm, the tensile rate was 200 mm / min, and the 180° peel strength of the sample was tested. Table 1 shows the 180° peel strength of the epoxy resin-based UV-resistant adhesives prepared in Examples 1-5 before and after UV curing after 30 min of curing. As can be seen from Table 1, the epoxy resin-based UV-resistant adhesive of the present invention has high pre-UV peel strength and low post-UV peel strength.

[0164] Table 1. Peel strength at 180° before and after UV curing for UV-cured adhesives prepared in Examples 1-5 after 30 min of curing.

[0165] Example 1 Example 2 Example 3 Example 4 Example 5 180° peel strength before UV irradiation 27.74N / 25mm 25.34N / 25mm 19.86N / 25mm 30.69N / 25mm 29.57N / 25mm 180° peel strength after UV irradiation 0.04 N / 25mm 0.85N / 25mm 0.25 N / 25mm 0.18N / 25mm 0.74N / 25mm Residual glue none small amount none none small amount

[0166] Those skilled in the art will readily understand that the above embodiments 1-5 are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An epoxy resin-based UV-resistant adhesive, characterized in that: The structural formula of the epoxy resin-based UV anti-tack adhesive is as follows: ； Where R1 is , or One of them; R2 is ; R3 is ; The curing time of the epoxy resin-based UV-resistant adhesive is 30 min; the 180° peel strength before UV irradiation is 19.86~30.69N / 25mm, and the 180° peel strength after UV irradiation is 0.04~0.85N / 25mm.

2. The preparation method of the epoxy resin-based UV anti-tack adhesive according to claim 1, characterized in that, The operation steps are as follows: (1) A carboxyl-terminated dicarboxylic acid and 1,6-hexanediol diglycidyl ether were dissolved in solvent A at a molar ratio of 1:1.1 to 1:1.

9. The reactants were synthesized under the action of catalyst A and polymerization inhibitor. Hexane was added to the reactants and stirred to precipitate the product. The product was then added to deionized water for further precipitation and drying to obtain a prepolymer with epoxy groups at both ends. The structure is as follows: The degree of polymerization n in the formula ranges from 2 to 11; The prepolymer has an epoxy value of 0.0466–0.1892 mol / 100g and a molecular weight of 1060–4290. The terminal carboxyl dicarboxylic acid mentioned is one of itaconic acid, citraconic acid, and fumaric acid; Solvent A is one of toluene, xylene, and N,N-dimethylformamide, and the amount of solvent used is 10-30 mL; Catalyst A is one of aluminum acetylacetonate, zinc acetylacetonate, and 2,4,6-tris(dimethylaminomethyl)phenol, and the amount added is 0.5% to 2% of the sum of the mass of the terminal carboxyl dicarboxylic acid and 1,6-hexanediol diglycidyl ether. The polymerization inhibitor is one of hydroquinone and 2,6-di-tert-butyl-p-cresol, and the amount added is 1% of the mass of the terminal carboxyl dicarboxylic acid; (2) The prepolymer and 4,4-diaminodiphenylmethane monomer were dissolved in solvent B at a molar ratio of 2.2:1 to 1.8:1 and reacted under the action of catalyst B and polymerization inhibitor to obtain epoxy resin-based adhesive. Solvent B is one of ethyl acetate, xylene, and N,N-dimethylformamide, and the amount of solvent used is 10-30 mL. The catalyst B is 2,4,6-tris(dimethylaminomethyl)phenol, and the amount added is 0.5% to 2% of the sum of the mass of the prepolymer and 4,4-diaminodiphenylmethane. The polymerization inhibitor is one of hydroquinone and 2,6-di-tert-butyl-p-cresol, and the amount added is 1% of the sum of the mass of the prepolymer and 4,4-diaminodiphenylmethane; (3) Cool the epoxy resin base adhesive to room temperature, add a photoinitiator to the epoxy resin base adhesive, stir for 1 hour, and obtain epoxy resin type UV anti-tack adhesive. The photoinitiator is one or more selected from diphenyl (2,4,6-trimethylphenylformyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylphenyl ketone, and 2-hydroxy-2-methyl-1-phenyl-1-propanone; the amount of photoinitiator added is 1 to 5% of the mass of the epoxy resin-based adhesive.

3. The preparation method according to claim 2, characterized in that: In step (1), the reaction conditions are: under a nitrogen atmosphere, at a temperature of 110-140°C, and for a reaction time of 3-5 hours.

4. The preparation method according to claim 2, characterized in that: In step (1), the precipitation conditions are as follows: the prepolymer is precipitated three times in sequence using n-hexane and deionized water at 80°C.

5. The preparation method according to claim 2, characterized in that: In step (1), the vacuum drying conditions are: vacuum degree of -85kPa, drying temperature of 50~60℃, and drying time of 12~24h.

6. The preparation method according to claim 2, characterized in that: In step (2), the reaction conditions are: under a nitrogen atmosphere, at a temperature of 80-100℃, for a reaction time of 3-5 hours.

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