UV (ultraviolet) light-cured resin composition as well as preparation method and application thereof

Abstract

The invention discloses a UV light-cured resin composition as well as a preparation method and application thereof. The UV light-cured resin composition is prepared from the following components in parts by mass: 40 to 60 parts of unsaturated monomer, 60 to 90 parts of polythiol compound, 1 to 6 parts of photoinitiator and 0.1 to 1 part of polymerization inhibitor, the unsaturated monomer comprises at least one of a substituted or unsubstituted aromatic ring, an aromatic heterocyclic ring and a carbocyclic ring; the structure of the polythiol compound is as follows: # imgabs0 #, R is one of H, F, Cl, methyl and trifluoromethyl, and R1 and R2 are respectively C2-C18 alkylene. The resin composition containing the specific unsaturated monomer and the polythiol compound shows relatively high bonding strength, high toughness and good humidity and heat resistance after being subjected to UV illumination curing, has high storage modulus at room temperature and high temperature, can effectively improve the stability and reliability of an adhesive layer at room temperature / high temperature, and has good application prospects. Good application prospects are realized in the aspects of electronic component sealing or bonding and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to a UV light-curing resin composition, a preparation method and an application thereof. Background Art

[0002] The manufacturing process for image sensor modules in mobile phones and other electronic products often requires adhesives and sealants that exhibit excellent mechanical, electrical, heat, and chemical resistance, as well as bonding strength. Furthermore, in the assembly and assembly of electronic components, maintaining reliability requires adhesives and sealants with high bonding strength, excellent moisture and heat resistance, and high reliability, regardless of the material being bonded.

[0003] UV-curable adhesives do not require heating during curing and can be rapidly cured using UV light initiation, effectively preventing damage to electronic devices caused by high temperatures. Therefore, they are currently one of the main adhesive types used for bonding or sealing electronic components. However, traditional acrylate free radical UV curing systems are susceptible to oxygen inhibition during UV curing due to the reaction mechanism of free radical chain self-polymerization. This oxygen inhibition effect brings many inconveniences to the curing process and reduces the performance of the cured product. The mercapto-ene system is a new type of UV curing system. Its gradual growth reaction mechanism makes the inhibition effect of oxygen on its curing process very small. Therefore, no inert gas protection is required during curing, the photoinitiation efficiency is greatly improved, and the amount of photoinitiator used can be reduced. However, the existing mercapto-ene UV light curing system (for example, a sealant for display elements disclosed in CN105706264A) mainly has the following problems: (1) the thiol compound used contains an ester bond structure that is easily hydrolyzed, which inevitably results in poor hydrolysis resistance of the product; (2) the polythiol curing agent used in the mercapto-ene UV light curing system has insufficient thiol functional groups, resulting in low cross-linking density after curing, low bonding strength, low storage modulus at room temperature and high temperature conditions, and poor connection reliability.

[0004] Based on this, there is an urgent need for a UV-curable resin composition that has high bonding strength, good toughness, high storage modulus and good resistance to wet and hot hydrolysis after curing, so as to meet the high performance requirements of adhesives such as bonding strength and reliability in the bonding and packaging of electronic components. Summary of the Invention

[0005] To solve the above problems, the present invention provides a UV light-curing resin composition, a preparation method and application thereof. Under the synergistic effect of an unsaturated monomer with a specific structure and a homemade polythiol compound, the prepared UV light-curing resin composition can be rapidly cured under UV light to form a high cross-linking density adhesive layer. The adhesive layer has high bonding strength, good toughness, and good resistance to wet and hot hydrolysis. It can maintain a relatively high storage modulus under room temperature and high temperature environments, thereby effectively improving the stability and reliability of the adhesive layer at room temperature / high temperature, and has good application prospects in the sealing or bonding of electronic parts.

[0006] Specifically, the following technical solutions are provided:

[0007] A first aspect of the present invention provides a UV light-curable resin composition, comprising the following components in parts by mass: 40-60 parts of an unsaturated monomer, 60-90 parts of a polythiol compound, 1-6 parts of a photoinitiator, and 0.1-1 parts of a polymerization inhibitor;

[0008] The unsaturated monomer comprises a first monomer containing three carbon-carbon double bonds, a second monomer containing two carbon-carbon double bonds, and a third monomer containing a single carbon-carbon double bond, and the first monomer, the second monomer, and the third monomer all contain at least one of an aromatic ring, an aromatic heterocycle, and a carbocycle;

[0009] The mass ratio of the first monomer to the second monomer and the third monomer is 1:(0.05-0.2):(0.05-0.25);

[0010] The structure of the polythiol compound is as follows:

[0011]

[0012] Wherein, R is one of H, F, Cl, methyl, and trifluoromethyl, R 1 、R 2 They are respectively C2-C18 alkylene.

[0013] Furthermore, the aromatic ring includes but is not limited to a benzene ring, the aromatic heterocyclic ring includes but is not limited to an s-triazine ring, and the carbon ring includes but is not limited to adamantane.

[0014] Furthermore, the first monomer is preferably triallyl isocyanurate, the second monomer is preferably bisphenol A diallyl ether, and the third monomer is preferably 2-adamantyl acrylate, including but not limited to the monomer types listed above. More preferably, the mass ratio of the first monomer to the second monomer and the third monomer is preferably 1:(0.07-0.15):(0.07-0.22).

[0015] Based on the current mercapto-ene UV light-curing system, there are problems such as low bonding strength, poor hydrolysis resistance, and low storage modulus. When used in electronic component bonding or packaging, it will lead to poor product reliability. To solve the above problems, the present invention provides a novel UV light-curing resin composition, which uses a first monomer (such as triallyl isocyanurate) with a rigid ring structure and three carbon-carbon double bonds as the main monomer, so that the cross-linking density of the resin composition after light curing is large, providing basic mechanical properties; at the same time, an appropriate amount of a second monomer (such as bisphenol A diallyl ether, which has a bisphenol-type structure to improve the bonding strength) and a third monomer (such as 2-adamantyl acrylate, which has an alicyclic chain to provide toughness) are introduced to adjust the toughness of the light-cured adhesive layer. By mixing the above three monomers in an appropriate ratio, the resin composition, after UV curing, has good flexibility and a high storage modulus under the premise that the bonding strength meets the use range, so that the adhesive layer will not lose strength because it is too soft, nor will it crack because it is too hard, thereby having excellent moisture and heat resistance. On this basis, the present invention adopts a homemade biphenyl type polythiol compound as a thiol curing agent, wherein the compound molecule contains a rigid biphenyl structure and four flexible alkylthiol groups, and the two alkylthiol groups distributed on the benzene ring are ortho-positions, and the compound is used as a curing agent to cure the resin, wherein the biphenyl structure of the curing agent can give the cured resin good heat resistance, and the four thiol groups with a specific position structure can further improve the heat resistance of the cured resin and significantly improve the toughness of the cured resin by high cross-linking density, and the compound does not have an easily hydrolyzed group, which can produce a high cross-linking density and not easily hydrolyzed after the resin composition comprising the curing agent is cured, thereby significantly improving the bonding strength, heat and moisture resistance, toughness, etc. of the cured resin. Under the synergistic effect of the above-mentioned monomers and the specific thiol curing agent (homemade polythiol compound), the resin composition exhibits high bonding strength and high toughness after UV curing, and still maintains relatively high bonding strength after high temperature and high humidity aging, and has a relatively high storage modulus at room temperature and high temperature environment, and can be used as an adhesive or sealant for bonding or packaging of electronic components, which is conducive to improving the reliability of electronic products.

[0016] Furthermore, in the structure of the polythiol compound, R is H, and R 1 、R 2 All are straight-chain C3 alkylene groups.

[0017] Furthermore, the preparation method of the mercaptan curing agent comprises the following steps:

[0018] (1) reacting a compound represented by Formula I and a compound represented by Formula II in the presence of a first base reagent, a first phase transfer catalyst, and a first solvent to obtain a first intermediate product represented by Formula III;

[0019] (2) heating the first intermediate product to obtain a second intermediate product represented by formula IV;

[0020] (3) reacting the second intermediate product with the compound represented by Formula V in the presence of a second base reagent, a second phase transfer catalyst, and a second solvent to obtain a third intermediate product represented by Formula VI;

[0021] (4) reacting the third intermediate product with thioacetic acid in the presence of a free radical initiator and a third solvent to obtain a fourth intermediate product represented by Formula VII;

[0022] (5) reacting the fourth intermediate product with an acid reagent or a base reagent in the presence of a fourth solvent to obtain the thiol curing agent;

[0023] The structures of the above formula I to formula VII are as follows:

[0024]

[0025] Wherein, R is one of H, F, Cl, methyl, and trifluoromethyl;

[0026] X is Cl or Br;

[0027] h is 1, and l is any integer from 0 to 16.

[0028] In some preferred embodiments, in step (1), the first alkaline reagent can be selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine; the first phase transfer catalyst can be selected from one or more of crown ethers, onium salts, ammonium salts, sulfonium salts, arsenic salts, polyethers, non-cyclic polyethers, and tertiary amine catalysts; the first solvent can be selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; the reaction temperature is 60-90°C, and the reaction time is 6-15h.

[0029] In some preferred embodiments, in step (2), the heating reaction temperature is 150-250° C., and the heating reaction time is 10-18 h.

[0030] In some preferred embodiments, in step (3), the second alkaline reagent can be selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine; the second phase transfer catalyst can be selected from one or more of crown ethers, onium salts, ammonium salts, sulfonium salts, arsenic salts, polyethers, non-cyclic polyethers, and tertiary amine catalysts; the second solvent can be selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; the reaction temperature is 60-90°C, and the reaction time is 6-15h.

[0031] In some preferred embodiments, in step (4), the free radical initiator is selected from one or more of azo, organic peroxide and redox initiators, such as azobisisobutyronitrile or benzoyl peroxide; the third solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol and methanol; the reaction temperature is 60-90°C, and the reaction time is 15-25h.

[0032] In some preferred embodiments, in step (5), the acid reagent is hydrochloric acid and / or sulfuric acid, and the base reagent includes but is not limited to sodium hydroxide; the fourth solvent is selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol; the reaction temperature is 55-95°C, and the reaction time is 25-40h.

[0033] Furthermore, the ratio of the total molar amount of carbon-carbon double bonds (derived from the unsaturated monomer) to the total molar amount of thiol groups (derived from the polythiol compound) in the UV light-curable resin composition is preferably 1:(0.9-1.2), for example, 1:0.9, 1:1, 1:1.1, 1:1.2, etc., including but not limited to the ratios listed above, more preferably 1:1.1.

[0034] Further, the photoinitiator is selected from 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-phenylbenzyl-2-dimethylamino-1-(4-morpholinylbenzylphenyl)butanone, 4-benzoyl-4'-methyl-diphenyl sulfide, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinylphenyl)-1-butanone. One or more of 1,2-dimethylthiophenone, 1,1'-(methylenebis-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone], 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-1-hexanone, bis-2,6-difluoro-3-pyrrolophenyl titanocene, methyl benzoylformate, benzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 4-chlorobenzophenone, methyl o-benzoylbenzoate, ethyl 4-dimethylaminobenzoate, isooctyl p-dimethylaminobenzoate, 4,4'-bis(diethylamino)benzophenone, isopropylthioxanthone, 2,4-diethylthioxanthone, and 2-ethylanthraquinone; in some preferred embodiments, the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone.

[0035] Furthermore, the polymerization inhibitor is selected from one or more of hydroquinone, p-hydroxyanisole, p-benzoquinone, methylhydroquinone, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 4-hydroxypiperidinol oxygen free radical, phenothiazine, and anthraquinone; in some preferred embodiments, the polymerization inhibitor is p-hydroxyanisole.

[0036] Furthermore, the UV light-curable resin composition further comprises 0.1-5 parts of a coupling agent and 0.1-20 parts of an auxiliary agent.

[0037] Furthermore, the coupling agent is selected from one or more of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 8-epoxypropoxyoctyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0038] Furthermore, the auxiliary agent is selected from one or more of fillers, antioxidants, stabilizers, flame retardants, diluents, pigments, defoamers, leveling agents, leveling agents, and ion capture agents, such as fumed silica.

[0039] The second aspect of the present invention provides a method for preparing the UV light-curing resin composition described in the first aspect, comprising weighing the components according to a formula and mixing them uniformly under light-proof conditions to obtain the UV light-curing resin composition.

[0040] A third aspect of the present invention provides a use of the UV light-curing resin composition described in the first aspect in preparing an adhesive for sealing or bonding electronic components.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention provides a UV-curable resin composition, which comprises three unsaturated monomers containing different carbon-carbon double bond functionalities and ring structures, and a polythiol compound with a specific structure. Under the synergistic effect of the above monomers and the specific polythiol compound, the resin composition exhibits high bonding strength and good toughness after UV curing, maintains relatively high bonding strength after high-temperature and high-humidity aging, and has a relatively high storage modulus at room temperature and high-temperature environments. The resin composition can be used as an adhesive or sealant in the bonding or packaging of electronic components, thereby improving the reliability of electronic products.

[0043] The thiol curing agent used in the present invention has low preparation cost and is suitable for industrial mass production. More importantly, the thiol curing agent is liquid at room temperature and has low viscosity. It can be directly used as a curing agent in the curing process of a UV light-curable resin composition, so that the resin composition can be rapidly cured by UV light at room temperature, and the internal stress and shrinkage generated during curing are small. Compared with other thiol curing agents, the resin composition cured with the thiol curing agent exhibits low water absorption, better bonding strength and moisture and heat resistance, and is more suitable for bonding and sealing electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl prepared in Example 1 1 H-NMR spectrum;

[0045] Figure 2 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl prepared in Example 1 13 C-NMR;

[0046] Figure 3 This is the IR spectrum of 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl prepared in Example 1. DETAILED DESCRIPTION

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items. The symbol "-" between two numbers herein means "to", for example, "40-60 parts of unsaturated monomer" means "40 to 60 parts of unsaturated monomer".

[0048] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0049] The sources of some of the raw materials used in the following examples and comparative examples are as follows:

[0050]

[0051] The structure of commercial polythiol PEMP is shown below:

[0052]

[0053] The biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl used in the following examples and comparative examples was prepared as follows:

[0054] (1) 18.6 g of 4,4'-dihydroxybiphenyl and 36.3 g of allyl bromide were dissolved in 250 mL of acetone, and then 55.3 g of anhydrous potassium carbonate and 2.6 g of 18-crown ether-6 were added. The mixture was stirred at 70°C under N2 protection for 12 h. After filtering, the solvent and excess raw materials in the filtrate were removed by vacuum distillation. The product was washed with water and dried to obtain the first intermediate product with a yield of 94%;

[0055] (2) 26.6 g of the first intermediate product was heated to 200° C. under N2 protection and reacted for 13 h, and the second intermediate product was purified with a yield of 84%;

[0056] (3) 26.6 g of the second intermediate product and 36.3 g of allyl bromide were dissolved in 250 mL of acetone, 55.3 g of anhydrous potassium carbonate and 2.6 g of 18-crown ether-6 were added, and the mixture was stirred at 70° C. under N2 protection for 10 h. After filtering, the solvent and excess raw materials in the filtrate were removed by vacuum distillation, and the filtrate was washed with water and dried to obtain the third intermediate product with a yield of 89%;

[0057] (4) 34.7 g of the third intermediate product and 45.7 g of thioacetic acid were dissolved in 300 mL of tetrahydrofuran, and 3.3 g of azobisisobutyronitrile was added. The mixture was stirred at 65° C. under N2 protection for 16 h. After filtering, the solvent and excess raw materials in the filtrate were removed by vacuum distillation. The filtrate was washed with water and dried to obtain the fourth intermediate product with a yield of 80%;

[0058] (5) 65.1 g of the fourth intermediate product and 10 g of concentrated hydrochloric acid were dissolved in 150 mL of tetrahydrofuran and 150 mL of methanol, and the mixture was stirred at 65° C. for 33 h under N2 protection. After filtration, the solvent and excess raw materials in the filtrate were removed by vacuum distillation. The filtrate was washed with water and dried to obtain a liquid product, 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl. Its H NMR spectrum, C NMR spectrum and IR spectrum were as follows: Figure 1-3 As shown, 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl was prepared.

[0059] Example 1

[0060] This embodiment provides a UV light-curable resin composition, which includes the following components in parts by mass: 40 parts of triallyl isocyanurate, 4 parts of bisphenol A diallyl ether, 5 parts of 2-adamantyl acrylate, 71 parts of a biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl, 1 part of a photoinitiator 2,2-dimethoxy-2-phenylacetophenone, 1 part of fumed silica, 1 part of a silane coupling agent, and 0.3 parts of a polymerization inhibitor p-hydroxyanisole.

[0061] Mix the above raw materials evenly at room temperature and in the dark, then degas and pack the discharged materials into black or brown sealed rubber tubes to obtain a resin composition.

[0062] Examples 2-9 and Comparative Examples 1-8

[0063] Examples 2-9 and Comparative Examples 1-8 respectively provide a UV light-curable resin composition, which differs from Example 1 only in that the type or content of the monomer and / or curing agent in the resin composition formula is different, and the rest are the same.

[0064] The types of monomers and curing agents in the UV-curable resin compositions prepared in Examples 1-9 and Comparative Examples 1-8 are shown in Table 1 below, wherein the thiol curing agent A is a homemade biphenyl-type polythiol compound 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl, the thiol curing agent B is a commercial polythiol PEMP, and the thiol curing agent C is 5,5'-bis(3-mercaptopropyl)-2,2'-bis(3-mercaptopropyloxy)biphenyl:

[0065] Table 1

[0066]

[0067] In the table, a / b is the ratio of the molar amount of carbon-carbon double bonds to the molar amount of mercapto groups in the resin composition.

[0068] Performance Testing

[0069] The performance tests of the resin compositions prepared in the above examples and comparative examples are as follows:

[0070] Curing conditions: Use a dispensing machine to squeeze out the glue from the hose, and then use a UV light source (wavelength 365nm, light intensity 1000mW / cm 2 ) Radiation curing for 15 seconds to obtain a cured sample.

[0071] Glass transition temperature (°C): The test was performed using a Q-800 dynamic mechanical analyzer (DMA) from TA Instruments, USA. The resin compositions prepared in the above embodiments and comparative examples were completely cured and formed into 42 mm × 8 mm × 0.3 mm sheets. The loss factor (tan δ) was measured as a function of temperature in a liquid nitrogen atmosphere and film stretching mode within a temperature range of -40 to 250°C. The heating rate was 10°C / min and the test frequency was 10 Hz, thereby determining the glass transition temperature (Tg) (°C) of the cured resin composition. The smaller the Tg value, the better the toughness of the cured resin.

[0072] Bond strength (MPa): The resin compositions prepared in the above embodiments and comparative examples were respectively coated on sheets to prepare test samples with a bonding area of ​​25.4 mm × 5 mm and a thickness of the adhesive layer of 0.1 mm. The test samples were cured respectively, and then the two sheets of the completely cured samples were pulled apart in opposite directions using a universal testing machine. The tests were carried out at an ambient temperature of 25°C, and the measured force values ​​were recorded as strength (MPa). The cured samples were subjected to heating and humidification conditions of 85°C / 85% RH / 750 h, and the shear bond strength (MPa) of the samples was tested again at an ambient temperature of 25°C and recorded.

[0073] Storage modulus (MPa): Storage modulus refers to the amount of energy stored in a material due to elastic (reversible) deformation when it is deformed, reflecting the elasticity of the material. The dynamic mechanical properties of the sample were tested using the Q800 dynamic thermomechanical analyzer from TA in the United States. The resin composition prepared in the above embodiments and comparative examples was completely cured and made into a 30mm×10mm×1mm sheet. The test adopted a single cantilever mode with a temperature range of 30 to 200°C, a heating rate of 3K / min, a vibration frequency of 1Hz, and an amplitude of 10μm. The storage modulus (MPa) of the cured resin composition at 25°C and 80°C was determined respectively.

[0074] The test results are shown in Table 2 below:

[0075] Table 2

[0076]

[0077] As can be seen from Table 2, the UV-curable resin compositions prepared in Examples 1-8 exhibit relatively high bonding strength after UV curing at room temperature, which is better than the bonding strength of the UV-curable resin composition (Comparative Example 1) prepared using commercial polythiol PEMP as a curing agent; and can still maintain high bonding strength after heating and humidification treatment, showing excellent heat and humidity resistance. The bonding strength of the UV-curable resin composition prepared in Comparative Example 1 after curing is significantly reduced after heating and humidification treatment. This is because the polythiol PEMP used contains an easily hydrolyzed ester bond structure, resulting in poor hydrolysis resistance of the formed adhesive layer. In addition, the UV-curable resin composition prepared in the above embodiments has good toughness and a relatively high storage modulus at room temperature and high temperature, and the products bonded or sealed therewith have better reliability.

[0078] As shown in Example 1 and Comparative Example 2, the position of the alkylthiol groups on the benzene ring in the polythiol compound affects the crosslink density of the adhesive layer after the resin composition is cured, thereby affecting the toughness, bonding strength, moisture and heat resistance, and storage modulus of the adhesive layer. In particular, the two alkylthiol groups on the benzene ring in the thiol curing agent used in Example 1 are ortho-positioned. The adhesive layer prepared by curing the epoxy resin with this compound exhibits superior toughness, bonding strength, moisture and heat resistance, and storage modulus.

[0079] From Examples 1, 6, 7 and Comparative Examples 3 and 4, it can be seen that the content of the monomer, the content of the curing agent, and the ratio a / b of the two will affect the performance of the resin composition after curing, especially the effect on the bond strength and storage modulus. Among them, if the relative content of the monomer is too little (Comparative Example 3) or the relative content of the curing agent is too much (Comparative Example 4), and the ratio a / b does not fall within the preferred range of 0.9-1.2, the bond strength of the prepared resin composition is significantly reduced, and the storage modulus is reduced.

[0080] As can be seen from Example 1 and Comparative Examples 5 and 6, the second monomer and the third monomer are both indispensable in the resin composition. The lack of the second monomer or the third monomer will cause the bonding strength of the prepared resin composition (such as Comparative Examples 5 and 6) to drop significantly, and the storage modulus to drop significantly, resulting in poor reliability of the products bonded or sealed therewith. In addition, as can be seen from Example 1 and Comparative Examples 7 and 8, the content of the second monomer and the third monomer in the UV light-curable resin composition protected by the present invention should not be too much. Too much content of the second monomer will cause the toughness of the UV light-curable resin composition to deteriorate and the strength to decrease. Although too much content of the third monomer will improve the toughness of the adhesive layer after the resin composition is cured, the adhesive layer is too soft, which will lead to a decrease in the bonding strength of the adhesive layer. Therefore, the content of the three monomers in the resin composition needs to be controlled within a suitable range, for example, 1: (0.05-0.2): (0.05-0.25), more preferably 1: (0.07-0.15): (0.07-0.22), to obtain an adhesive layer with both high bonding strength and good toughness.

[0081] In summary, the present invention introduces three monomers with specific structures into the UV light-curable resin composition, and by controlling the content ratio of the three monomers and coordinating a specific thiol curing agent (self-made polythiol compound), it can exhibit high bonding strength and high toughness after UV curing, and still maintains relatively high bonding strength after high temperature and high humidity aging, and has a relatively high storage modulus at room temperature and high temperature environments. It can be used as an adhesive or sealant for bonding or packaging electronic components, effectively improving the reliability of electronic products.

[0082] The above embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are within the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

Claims

1. A UV light-curable resin composition, characterized in that: The UV light-curable resin composition comprises the following components by mass: 40-60 parts of unsaturated monomers, 60-90 parts of polythiol compounds, 1-6 parts of photoinitiators, and 0.1-1 parts of inhibitors; The unsaturated monomer comprises a first monomer containing three carbon-carbon double bonds, a second monomer containing two carbon-carbon double bonds, and a third monomer containing a single carbon-carbon double bond, and the first monomer, the second monomer, and the third monomer all contain at least one of an aromatic ring, an aromatic heterocycle, and a carbon ring; The mass ratio of the first monomer to the second monomer and the third monomer is 1:(0.05-0.2):(0.05-0.25); The structure of the polythiol compound is as follows: Wherein, R is one of H, F, Cl, methyl, and trifluoromethyl, and R 1 , R 2 They are C2-C18 alkylene respectively.

2. The UV light-curable resin composition according to claim 1, characterized in that: The first monomer is triallyl isocyanurate; The second monomer is bisphenol A diallyl ether; The third monomer is 2-adamantyl acrylate.

3. The UV light-curable resin composition according to claim 2, characterized in that: The mass ratio of the first monomer to the second monomer and the third monomer is 1:(0.07-0.15):(0.07-0.22).

4. The UV light-curable resin composition according to claim 1, characterized in that: In the structure of the polythiol compound, R is H, and R 1 , R 2 All are straight chain C3 alkylene.

5. The UV light-curable resin composition according to claim 1, characterized in that: The ratio of the total molar amount of carbon-carbon double bonds to the total molar amount of mercapto groups in the UV light-curable resin composition is 1:(0.9-1.2).

6. The UV light-curable resin composition according to claim 1, characterized in that: The photoinitiator is selected from 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenyl propiophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinylbenzylphenyl)butanone, 4-benzoyl-4'-methyl-diphenyl sulfide, 2-(4-methylbenzyl)-2-(dimethylamino)-1-propanone, -1-(4-morpholinophenyl)-1-butanone, 1,1'-(methylenebis-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone], 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-1-hexanophenone, bis-2,6-difluoro-3-pyrrolophenyl titanocene, methyl benzoylformate, benzophenone, 4-methylbenzophenone, 4-phenylbenzophenone, 4-chlorobenzophenone, methyl o-benzoylbenzoate, ethyl 4-dimethylaminobenzoate, isooctyl p-dimethylaminobenzoate, 4,4'-bis(diethylamino)benzophenone, isopropylthioxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone; The polymerization inhibitor is selected from one or more of hydroquinone, p-hydroxyanisole, p-benzoquinone, methylhydroquinone, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, 4-hydroxypiperidinol oxygen free radical, phenothiazine, and anthraquinone.

7. The UV light-curable resin composition according to claim 1, characterized in that: The UV light-curable resin composition further comprises 0.1-5 parts of a coupling agent and 0.1-20 parts of an auxiliary agent.

8. The UV light-curable resin composition according to claim 7, characterized in that: The coupling agent is selected from one or more of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 8-epoxypropoxyoctyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane; The auxiliary agent is selected from one or more of fillers, antioxidants, stabilizers, flame retardants, diluents, pigments, defoamers, leveling agents, leveling agents, and ion capture agents.

9. A method for preparing the UV light-curable resin composition according to any one of claims 1 to 8, characterized in that: The components are weighed according to the formula and mixed evenly under light-proof conditions to obtain the UV light-curable resin composition.

10. Use of the UV light-curing resin composition according to any one of claims 1 to 8 in preparing an adhesive for sealing or bonding electronic components.

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