Resin composition with high bonding strength as well as preparation method and application thereof

Abstract

The invention discloses a resin composition with high bonding strength as well as a preparation method and application thereof. The resin composition comprises (a) one or combination of epoxy resin and photosensitive resin; (b) the curing agent has a structure as shown in a general formula; and (c) a curing accelerator: epoxy resin corresponds to amine, and a photoinitiator needs to be added when photosensitive resin is contained. The preparation of the curing agent is realized through five-step reaction of substitution of dihydroxy diphenylalkyl ketone and halogenated olefin, substituent group rearrangement, secondary substitution, thioacetic acid addition and hydrolysis. The composition has the characteristics of rapid gelling, high bonding strength, excellent chemical resistance, strong hydrophobicity and the like, and is suitable for bonding, sealing or coating materials of electronic components.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a resin composition with high adhesive strength, its preparation method, and its application. Background Technology

[0002] With the development of industrial technology, the requirements for the performance of adhesive materials are becoming increasingly stringent. This is especially true in industries such as aerospace, automotive manufacturing, and electronic packaging, where strict requirements are placed on the mechanical properties, electrical properties, resistance to damp heat, chemical resistance, and adhesive strength of materials. Common resins are generally liquid or semi-solid at room temperature and require a curing process to solidify. Polythiol compounds possess multiple thiol groups, which can react with epoxy groups or unsaturated groups in the resin to form stable thioether bonds. Thiol compounds with multiple thiol groups have a wide range of applications, commonly used as curing agents for epoxy resins and UV-curable resins.

[0003] One-component epoxy resins are widely used in electronic packaging, adhesives, and other fields due to their ease of operation and fast curing speed. When polythiol compounds are used as curing agents for epoxy resins, they offer the advantage of rapid curing at lower temperatures, meeting the requirements for low-temperature curing in one-component epoxy resin compositions. Photosensitive resins are resin materials that cure rapidly under light irradiation using photoinitiators and are widely used in 3D printing, microelectronics manufacturing, and other fields. However, traditional acrylate free radical UV curing systems experience volume shrinkage and oxygen inhibition during curing, severely reducing material performance. When polythiol compounds are used as curing agents for photocurable resins, sulfhydryl-olefins, as a novel UV curing system, eliminate the effects of oxygen inhibition through their progressively increasing reaction mechanism. The chain transfer reaction between sulfhydryl groups and double bonds also reduces polymerization volume shrinkage. Photothermal dual-curing resins combine the advantages of photocuring and thermal curing, achieving rapid curing under both light and heat. When polythiol compounds are used as curing agents for photothermal dual-curing resins, not only can low-temperature rapid curing be achieved, but the negative impacts on product performance caused by oxygen inhibition and volume shrinkage can also be eliminated.

[0004] In summary, how to prepare resin compositions with high crosslinking density, short gel time, high bonding strength, excellent chemical resistance, and excellent water resistance after curing by using appropriate polythiol compounds and main resins has become an urgent problem to be solved. Summary of the Invention

[0005] In view of the performance defects of existing thiol compounds in cured resin compositions, this application solves the problems of high resistance to humid heat and high bonding strength of cured resin compositions.

[0006] On one hand, the present invention provides a resin composition with high adhesive strength, the resin composition comprising:

[0007] (a) Resin: The resin includes one or a combination of epoxy resin and photosensitive resin;

[0008] (b) Curing agent: The curing agent is a diphenylalkyl ketone polythiol compound having a structure as shown in general formula (I):

[0009]

[0010] Among them, R 1 and R 2 Each is independently selected from one of the alkylene groups having 1 to 5 carbon atoms, R 3 Selected from one of the alkylene groups having 0 to 5 carbon atoms;

[0011] (c) Curing accelerator: When the resin is an epoxy resin, the curing accelerator is an amine; when the resin is a combination of epoxy resin and photosensitive resin, the curing accelerator is a free radical photoinitiator and an amine.

[0012] Preferably, the curing agent has a structure as shown in general formula (II):

[0013]

[0014] Preferably, the diphenylalkyl ketone polythiol compound is prepared according to the following steps:

[0015] (1) Add dihydroxydiphenyl alkyl ketone, first haloolefin compound and first solvent to a reaction vessel, then add first basic catalyst and phase transfer catalyst, and then heat to 60-90℃ under nitrogen atmosphere for 8-15h to obtain first intermediate product;

[0016] (2) The first intermediate product is added to the reaction vessel and heated to 150-250°C under nitrogen protection for 8-16 hours to obtain the second intermediate product;

[0017] (3) The second intermediate product, the second haloolefin compound and the second solvent are added to the reaction vessel, and then the second basic catalyst and the phase transfer catalyst are added. The reaction is then heated to 60-90°C under a nitrogen atmosphere for 8-15 hours to obtain the third intermediate product.

[0018] (4) Add the third intermediate, thioacetic acid, and the third solvent to the reaction vessel, then add the free radical initiator, and then heat to 60-90℃ under a nitrogen atmosphere for 16-25 h to obtain the fourth intermediate.

[0019] (5) The fourth intermediate and the fourth solvent are added to the reaction vessel and then heated to 60-90°C under a nitrogen atmosphere for 25-35 h to obtain the diphenyl alkyl ketone polythiol compound.

[0020] Preferably, in the method for preparing the diphenylalkyl ketone polythiol compound, the dihydroxy diphenylalkyl ketone is a diphenyl ring linked by an alkyl ketone, each benzene ring containing at least one phenolic hydroxyl group, and its structural formula is as follows: Among them, R 3 It is one of the alkylene groups having 0 to 5 carbon atoms;

[0021] The first and second haloalkene compounds are respectively selected from alkanes whose molecular chains are capped with bromine or chlorine at one end and double bonds at the other end, and their structures are as follows: Where X represents chlorine or bromine, R 4 It is one of the alkylene groups having 1 to 5 carbon atoms.

[0022] Preferably, the dihydroxydiphenyl ketone is 1,2-bis(4-hydroxyphenyl)ethyl ketone or 4,4'-dihydroxydibenzophenone; the first and second haloolefin compounds are allyl bromide or allyl chloride.

[0023] Preferably, the first and second solvents are selected from one or more of acetone, ethanol, dimethyl sulfoxide, and N,N-dimethylformamide;

[0024] The first and second basic compounds are respectively selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine;

[0025] The free radical initiator includes one or more of azo, organic peroxide, and redox initiators;

[0026] The third and fourth solvents are selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol.

[0027] Preferably, when the resin is an epoxy resin, the resin composition comprises 48 to 53 parts by weight of epoxy resin, 32 to 39 parts by weight of diphenyl alkyl ketone polythiol compound curing agent, and 0.1 to 5 parts by weight of amine curing accelerator.

[0028] When the resin is a combination of epoxy resin and photosensitive resin, the resin composition includes 37-40 parts by weight of epoxy resin, 10-20 parts by weight of photosensitive resin, 25-28 parts by weight of diphenyl alkyl ketone polythiol compound, 1-5 parts by weight of free radical photoinitiator, 1-5 parts by weight of amine curing accelerator, 0.5-3 parts by weight of stabilizer, and 0.1-1 parts by weight of polymerization inhibitor.

[0029] Preferably, the resin composition further includes an additive selected from at least one of fillers, antioxidants, stabilizers, polymerization inhibitors, flame retardants, adhesion promoters, coupling agents, toughening agents, diluents, pigments, defoamers, leveling agents, wetting agents, homogenizers, and ion traps; the content of the additive is 0.01 to 10 parts by weight.

[0030] Secondly, this application provides a method for preparing the resin composition, the method comprising: mixing the resin, diphenyl alkyl ketone polythiol compound, accelerator and additives uniformly using a planetary disperser, degassing under vacuum and then filling to obtain the target product.

[0031] Thirdly, this application provides for the use of the resin composition as an adhesive, sealant, or coating material for bonding, sealing, or coating electronic components.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0033] (1) The present invention prepares a resin composition containing a diphenylalkyl ketone polythiol compound as a curing agent. The diphenylalkyl ketone polythiol compound has a biphenyl ring structure with ketone carbonyl and methylene linked. When used as a curing agent, it has a certain rigidity due to the difficulty of sliding of ketone carbonyl and methylene molecules. However, compared with the biphenyl structure, it is an asymmetric structure and has a relatively low crystallinity. The carbonyl structure enables the resin composition to have a stronger hydrogen bonding ability when crosslinking, and the gelation speed is fast. The ketone carbonyl also has a higher cohesive energy density when forming the final composition, which improves the bonding strength. The dense asymmetric arrangement can form an anti-permeation network, so that the cured product has ultra-high water resistance and chemical resistance.

[0034] This diphenyl alkyl ketone polythiol compound is liquid at room temperature. Its asymmetric structure reduces crystallinity, maintains room temperature liquid processability, and has low viscosity. It can be directly used as a curing agent in the curing process of resin compositions.

[0035] (2) The resin composition prepared by the present invention has good curing effect, high bonding strength after curing, short gel time and rapid positioning, which improves the generation efficiency. It has a high performance retention rate in high temperature and high humidity / alkaline environment, which can meet the high reliability requirements of automotive electronics, aerospace and other industries. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0038] In a first aspect, this application provides a resin composition with high adhesive strength, the resin composition comprising:

[0039] (a) Resin: The resin includes one or a combination of epoxy resin and photosensitive resin;

[0040] (b) Curing agent: The curing agent is a diphenylalkyl ketone polythiol compound having a structure as shown in general formula (I):

[0041]

[0042] Among them, R 1 and R 2 Each is independently selected from one of the alkylene groups having 1 to 5 carbon atoms, R 3 Selected from one of the alkylene groups having 0 to 5 carbon atoms;

[0043] (c) Curing accelerator: When the resin is an epoxy resin, the curing accelerator is an amine; when the resin is a combination of epoxy resin and photosensitive resin, the curing accelerator is a free radical photoinitiator and an amine.

[0044] The resin composition prepared using this embodiment has good curing effect, high bonding strength after curing, short gel time for rapid positioning, and improved generation efficiency. It also has a high performance retention rate in high temperature and high humidity / alkaline environments, which can meet the high reliability requirements of automotive electronics, aerospace and other fields.

[0045] In some embodiments, the curing agent has a structure as shown in general formula (II):

[0046]

[0047] A resin composition employing a diphenylalkyl ketone polythiol compound as a curing agent is described. This compound possesses a biphenyl ring structure linked by a ketone carbonyl group and a methylene group. When used as a curing agent, the ketone carbonyl and methylene molecules exhibit a degree of rigidity due to the difficulty in slippage. However, compared to biphenyl, which has an asymmetric structure, its crystallinity is relatively lower. The carbonyl structure enables stronger hydrogen bonding during crosslinking of the resin composition, allowing for rapid gelation. The high cohesive energy density effectively enhances the bond strength. The dense, asymmetric arrangement forms an impermeable network, giving the cured product extremely high water and chemical resistance.

[0048] This diphenyl alkyl ketone polythiol compound is liquid at room temperature. Its asymmetric structure reduces crystallinity, maintains room temperature liquid processability, and has low viscosity. It can be directly used as a curing agent in the curing process of resin compositions.

[0049] In some embodiments, the diphenylalkyl ketone polythiol compound is prepared according to the following steps:

[0050] (1) Add dihydroxydiphenyl alkyl ketone, first haloolefin compound and first solvent to a reaction vessel, then add first basic catalyst and phase transfer catalyst, and then heat to 60-90℃ under nitrogen atmosphere for 8-15h to obtain first intermediate product;

[0051] (2) The first intermediate product is added to the reaction vessel and heated to 150-250°C under nitrogen protection for 8-16 hours to obtain the second intermediate product;

[0052] (3) The second intermediate product, the second haloolefin compound and the second solvent are added to the reaction vessel, and then the second basic catalyst and the phase transfer catalyst are added. The reaction is then heated to 60-90°C under a nitrogen atmosphere for 8-15 hours to obtain the third intermediate product.

[0053] (4) Add the third intermediate, thioacetic acid, and the third solvent to the reaction vessel, then add the free radical initiator, and then heat to 60-90℃ under a nitrogen atmosphere for 16-25 h to obtain the fourth intermediate.

[0054] (5) The fourth intermediate and the fourth solvent are added to the reaction vessel and then heated to 60-90°C under a nitrogen atmosphere for 25-35 h to obtain the diphenyl alkyl ketone polythiol compound.

[0055] In some embodiments, in the method for preparing the diphenylalkyl ketone polythiol compound, the dihydroxy diphenylalkyl ketone is a diphenyl ring linked by an alkyl ketone, each benzene ring containing at least one phenolic hydroxyl group, and its structural formula is as follows: Among them, R 3 It is one of the alkylene groups having 0 to 5 carbon atoms;

[0056] The first and second haloalkene compounds are respectively selected from alkanes whose molecular chains are capped with bromine or chlorine at one end and double bonds at the other end, and their structures are as follows: Where X represents chlorine or bromine, R 4 It is one of the alkylene groups having 1 to 5 carbon atoms.

[0057] In some embodiments, the dihydroxydiphenyl ketone is 1,2-bis(4-hydroxyphenyl) ethyl ketone or 4,4'-dihydroxybenzophenone, preferably 1,2-bis(4-hydroxyphenyl) ethyl ketone; the first and second halogenated olefin compounds are allyl bromide or allyl chloride, preferably allyl bromide.

[0058] In some embodiments, the first and second solvents are selected from one or more of acetone, ethanol, dimethyl sulfoxide, and N,N-dimethylformamide; acetone is preferred because it has better solubility in the raw materials and makes post-processing more convenient.

[0059] The first and second basic compounds are selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine; acetone is preferred because potassium carbonate has milder reaction conditions, avoids side reactions caused by strong bases, and has a high yield.

[0060] The free radical initiator includes one or more of azo, organic peroxide, and redox initiators; azo is preferred because of its mild reaction, inert and easily separated byproducts, and good solvent compatibility.

[0061] The third and fourth solvents are selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol.

[0062] In some embodiments, when the resin is an epoxy resin, the resin composition comprises 48 to 53 parts by weight of epoxy resin, such as 48, 49, 50, 51, 52, 53 or any value therebetween; 32 to 39 parts by weight of diphenyl alkyl ketone polythiol compound curing agent, such as 32, 33, 34, 35, 36, 37, 38, 39 or any value therebetween; and 0.1 to 5 parts by weight of amine curing accelerator, such as 0.1, 0.5, 1, 2, 3, 4, 5 or any value therebetween.

[0063] When the resin is a combination of epoxy resin and photosensitive resin, the resin composition comprises 37 to 40 parts by weight of epoxy resin, such as 37, 38, 39, 40 or any value therebetween; and 10 to 20 parts by weight of photosensitive resin, such as 10, 15, 20 or any value therebetween; 25 to 28 parts by weight of diphenyl alkyl ketone polythiol compound, such as 25, 26, 27, 28 or any value therebetween; 1 to 5 parts by weight of free radical photoinitiator, such as 1, 2, 3, 4, 5 or any value therebetween; 1 to 5 parts by weight of amine curing accelerator, such as 1, 2, 3, 4, 5 or any value therebetween; 0.5 to 3 parts by weight of stabilizer, such as 0.5, 1, 2, 3 or any value therebetween; and 0.1 to 1 part by weight of polymerization inhibitor, such as 0.1, 0.2, 0.4, 0.6, 0.8, 1 or any value therebetween.

[0064] In some embodiments, the resin composition further includes an additive selected from at least one of fillers, antioxidants, stabilizers, polymerization inhibitors, flame retardants, adhesion promoters, coupling agents, toughening agents, diluents, pigments, defoamers, leveling agents, wetting agents, homogenizers, and ion trapping agents; the additive is present in an amount of 0.01 to 10 parts by weight, such as 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or any value between them.

[0065] Secondly, this application provides a method for preparing the resin composition, the method comprising: mixing the resin, diphenyl alkyl ketone polythiol compound, accelerator and additives uniformly using a planetary disperser, degassing under vacuum and then filling to obtain the target product.

[0066] Thirdly, this application provides for the use of the resin composition as an adhesive, sealant, or coating material for bonding, sealing, or coating electronic components.

[0067] The present invention will be further illustrated by the following examples.

[0068] In the synthesis example, the raw materials used in the preparation of the diphenylalkyl ketone polythiol compound are as follows: 1,2-bis(4-hydroxyphenyl)ethyl ketone is from Adamas Reagent Co., Ltd., grade 3426706D; allyl bromide is from Adamas Reagent Co., Ltd., grade 13125A; anhydrous potassium carbonate is from Adamas Reagent Co., Ltd., grade G67526G; 18-crown ether-6 is from Adamas Reagent Co., Ltd., grade 30243B; thioacetic acid is from Sinopharm Chemical Reagent Co., Ltd., grade 80128126; and azobisisobutyronitrile is from Adamas Reagent Co., Ltd., grade 80477A.

[0069] The main raw materials used in Examples 1-7 and Comparative Examples 1-4 are as follows: Bisphenol A type epoxy resin was purchased from Mitsubishi Chemical's E51; pentaerythritol tetra(3-mercaptopropionate) was PETMP from SC Organic Chemicals Co., Ltd., Japan; tricyclodecanediethanol diacrylate resin was ETERMER 2204 from Changxing Materials; 2,2-dimethoxy-2-phenylacetophenone was DMPA from Adamas Reagent Co., Ltd.; imidazole latent curing accelerator was Ajinomoto PN23 from Japan; fumed silica was REOLOSIL QS-10 from Tokuyama Corporation, Japan; triisopropyl borate stabilizer was W330012 from Saen Chemical Technology (Shanghai) Co., Ltd.; silane coupling agent was KBM403 from Shin-Etsu Chemical Industry Co., Ltd., Japan; and trifluoroacetic acid was 81548A from Adamas Reagent Co., Ltd.

[0070] Synthesis example

[0071] This synthetic example illustrates the preparation of the diphenylalkyl ketone polythiol compound provided by the present invention. The specific steps are as follows:

[0072] (1) 22.8 g of 1,2-bis(4-hydroxyphenyl) ethyl ketone, 36.29 g of allyl bromide and 300 ml of acetone were added to a reaction vessel, followed by 55.28 g of anhydrous potassium carbonate and 2.64 g of 18-crown ether-6. The mixture was then heated to 70 °C and reacted for 10 h under a nitrogen atmosphere to obtain compound a.

[0073] (2) 30.8 g of the first intermediate product was added to the reaction vessel and heated to 200 °C for 12 h under nitrogen protection to obtain compound b;

[0074] (3) Add 30.8g of the second intermediate product, 36.29g of allyl bromide and 300ml of acetone to the reaction vessel, then add 55.28g of anhydrous potassium carbonate and 2.64g of 18-crown ether-6, and then heat to 70℃ under a nitrogen atmosphere for 10h to obtain compound c;

[0075] (4) 38.9 g of the third intermediate, 45.67 g of thioacetic acid, and 300 ml of tetrahydrofuran were added to the reaction vessel, and then 3.28 g of azobisisobutyronitrile was added. The mixture was then heated to 70 °C under a nitrogen atmosphere and reacted for 16 h to obtain compound d.

[0076] (5) Add 52.5g of the fourth intermediate product, 150ml of methanol and 150ml of tetrahydrofuran to the reaction vessel, and then heat to 70℃ for 28h under a nitrogen atmosphere to obtain diphenyl alkyl ketone polythiol compound.

[0077] The synthesis steps are as follows:

[0078]

[0079] Example 1

[0080] This embodiment illustrates the preparation of the thermosetting resin composition provided by the present invention. The resin composition comprises the following components by weight: 50 parts of bisphenol A type epoxy resin jER828, 35 parts of the diphenyl alkyl ketone polythiol compound obtained in the synthesis example, 1.5 parts of latent curing accelerator PN23, 1 part of fumed silica REOLOSIL QS-10, 1 part of stabilizer triisopropyl borate, and 1 part of silane coupling agent KBM403.

[0081] The above raw materials are mixed evenly under normal temperature conditions, and then vacuum degassing is performed. The mixture is then discharged and packaged into sealed tubes to obtain the resin composition.

[0082] Example 2

[0083] The thermosetting resin composition was prepared according to the method of Example 1, except that 48 parts of bisphenol A type epoxy resin jER828 and 37 parts of the diphenyl alkyl ketone polythiol compound obtained in the synthesis example were added, and the other conditions were the same as in Example 1, to obtain the thermosetting resin composition.

[0084] Example 3

[0085] The thermosetting resin composition was prepared according to the method of Example 1, except that 53 parts of bisphenol A type epoxy resin jER828 and 32 parts of the diphenyl alkyl ketone polythiol compound obtained in the synthesis example were added, and the other conditions were the same as in Example 1, to obtain the thermosetting resin composition.

[0086] Example 4

[0087] This embodiment illustrates the preparation of the photothermal dual-curing resin composition provided by the present invention. The resin composition comprises the following components by weight: 38.5 parts of bisphenol A type epoxy resin E51, 15 parts of photosensitive resin tricyclodecanedimethylethanol diacrylate, 26.5 parts of the diphenylalkyl ketone polythiol compound obtained in the synthesis example, 1.5 parts of latent curing accelerator PN23, 1 part of free radical photoinitiator (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1 part of fumed silica QS-10, 0.2 parts of stabilizer triisopropyl borate, 0.2 parts of polymerization inhibitor p-hydroxyanisole, and 1 part of silane coupling agent Z-6062.

[0088] Mix the above raw materials evenly under light-proof and room temperature conditions, then degas the mixture, and dispense it into black or brown sealed tubes to obtain the photothermal dual-curing resin composition.

[0089] Example 5

[0090] The photothermal dual-curing resin composition was prepared according to the method of Example 4, except that 37 parts of bisphenol A type epoxy resin jER828 and 28 parts of the diphenyl alkyl ketone polythiol compound obtained in the synthesis example were added, and the other conditions were the same as in Example 4, to obtain the photothermal dual-curing resin composition.

[0091] Example 6

[0092] The photothermal dual-curing resin composition was prepared according to the method of Example 4, except that 38 parts of bisphenol A type epoxy resin jER828 and 27 parts of the diphenyl alkyl ketone polythiol compound obtained in the synthesis example were added, and the other conditions were the same as in Example 4, to obtain the photothermal dual-curing resin composition.

[0093] Example 7

[0094] The photothermal dual-curing resin composition was prepared according to the method of Example 4, except that 40 parts of bisphenol A type epoxy resin jER828 and 25 parts of the diphenyl alkyl ketone polythiol compound obtained in the synthesis example were added, and the other conditions were the same as in Example 4, to obtain the photothermal dual-curing resin composition.

[0095] Example 8

[0096] The photothermal dual-curing resin composition was prepared according to the method of Example 4, except that 10 parts of photosensitive resin tricyclodecanediethanol diacrylate were added, and the other conditions were the same as in Example 4, to obtain the photothermal dual-curing resin composition.

[0097] Example 9

[0098] The photothermal dual-curing resin composition was prepared according to the method of Example 4, except that 20 parts of photosensitive resin tricyclodecanediethanol diacrylate were added, and the other conditions were the same as in Example 4, to obtain the photothermal dual-curing resin composition.

[0099] Comparative Example 1

[0100] The thermosetting resin composition was prepared according to the method of Example 1, except that the diphenyl alkyl ketone polythiol compound in Example 1 was replaced with the commercial polythiol curing agent pentaerythritol tetrakis(3-mercaptopropionic acid) ester PEMP, and the other conditions were the same as in Example 1, to obtain the thermosetting resin composition.

[0101] Comparative Example 2

[0102] The photothermal dual-curing resin composition was prepared according to the method of Example 4, except that the diphenyl alkyl ketone polythiol compound in Example 4 was replaced with the commercial polythiol curing agent pentaerythritol tetrakis(3-mercaptopropionic acid) ester PEMP, and the other conditions were the same as in Example 4, to obtain the photothermal dual-curing resin composition.

[0103] Comparative Example 3

[0104] The thermosetting resin composition was prepared according to the method of Example 1, except that the diphenylalkyl ketone polythiol compound in Example 1 was replaced with an equal amount of 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl (structure: The thermosetting resin composition was obtained by replacing the original with the other conditions as in Example 1.

[0105] Comparative Example 4

[0106] The photothermal dual-curing resin composition was prepared according to the method of Example 4, except that the diphenyl alkyl ketone polythiol compound in Example 4 was replaced with an equal amount of 4,4'-bis(3-mercaptopropoxy)-3,3'-bis(3-mercaptopropyl)biphenyl, and the other conditions were the same as in Example 4, to obtain the photothermal dual-curing resin composition.

[0107] Test case

[0108] (1) Curing conditions: The resin compositions prepared in Examples 1-3 and Comparative Examples 1 and 3 were extruded from the tube using a dispensing machine and then cured at 80°C for 45 minutes to obtain the cured samples. The resin compositions prepared in Examples 4-9 and Comparative Examples 3 and 4 were extruded from the tube using a dispensing machine and first cured using an ultraviolet light source (wavelength 365nm, light intensity 1000mW / cm²). 2 Radiation curing for 2 seconds, followed by curing at 80℃ for 45 minutes, yields the cured sample.

[0109] (2) Adhesive strength (MPa): The resin compositions prepared in the above examples and comparative examples were coated on the sheets to make test samples. The bonding area was 12.5mm × 25mm, and the thickness of the adhesive layer was 0.1mm. The test samples were cured. Then, the fully cured samples were pulled apart in opposite directions using a universal testing machine and tested at an ambient temperature of 25°C. The measured force value was recorded as strength (MPa).

[0110] (3) Chemical resistance (g): The resin compositions prepared in the above examples and comparative examples were respectively made into block samples to make test samples. Then, the test samples were cured. Then, 40 mg of the fully cured sample was placed in a 10 wt% sodium hydroxide aqueous solution and soaked at 80°C for 48 h. The sample was taken out, dried and weighed, and the mass loss rate (%) was calculated.

[0111] (4) Water droplet angle (°): The resin compositions obtained in the above examples and comparative examples were added into a syringe, and the water droplet angle was tested using a fully automatic water droplet angle tester. The sitting drop method was adopted, the amount of resin was 3μL, and the substrate was a PCB board with a value of 30-32 dynes. After the sample was dropped onto the substrate, it was left to stand for 5 seconds and the water droplet angle data was read. Five samples were tested in each example group, and the average value of the final test results was used to obtain the water droplet angle of the resin composition.

[0112] (5) Water absorption rate (%): The resin compositions prepared in the above examples and comparative examples were respectively made into block samples with a size of 20×10×5mm, and then the test samples were cured. The fully cured samples were placed in distilled water at 80℃ and soaked at 80℃ for 72h. The samples were taken out and weighed, and the water absorption rate (%) was calculated.

[0113] (6) Gel time: Drop about 0.5g of the adhesive composition to be tested onto the surface of the aluminum substrate and place it on an 80℃ heating table to test the gel time. The gel time is the turning point when the adhesive composition changes from liquid to solid.

[0114] The test results are shown in Table 1 below:

[0115] Table 1

[0116]

[0117] As can be seen from Examples 1-3, when diphenyl alkyl ketone polythiols are used as curing agents in thermosetting systems, the best overall performance is achieved when the functional group ratio of epoxy resin to diphenyl alkyl ketone polythiols in Example 1 is 1:1.048. In Example 2, due to the increased overall thiol content caused by the 1:1.154 functional group ratio of epoxy resin to diphenyl alkyl ketone polythiols, the gel time is 0.3 min faster than in the previous examples. However, the excess residual curing agent affects the density of the adhesive layer, resulting in a decrease in bond strength, chemical resistance, and water resistance. In Example 2, due to the 1:0.904 functional group ratio of epoxy resin to diphenyl alkyl ketone polythiols, the overall thiol content is reduced, resulting in a lower crosslinking density, reduced bond strength, and decreased chemical and water resistance, and the gel time is also relatively slower. In Example 1, the gel time of the commercial curing agent was shortened from 6.0 min to 5.3 min compared to Comparative Example 1, which is significantly shorter than the 9.0 min gel time of the biphenyl polythiol curing agent in Comparative Example 1. After complete curing, it also has higher bonding strength, chemical resistance and strong hydrophobic properties.

[0118] As can be seen from Examples 4-7, the diphenyl alkyl ketone polythiol compound, as a curing agent in the room temperature curing system, exhibits the same trend. The addition of photocurable resin improves rapid positioning, but also increases the need for operating equipment. Therefore, the appropriate system should be selected based on the specific production line. Examples 8-9 show that increasing or decreasing the amount of photosensitive resin has a certain impact on the curing strength. Reducing the amount of photosensitive resin leads to a decrease in crosslinking degree, resulting in lower bond strength, and consequently, reduced water and chemical resistance. Increasing the amount of photosensitive resin leads to an increase in crosslinking degree, but also results in excessive hardness and increased cohesive energy, leading to a decrease in bond strength, and consequently, reduced water and chemical resistance. Therefore, when combining epoxy resin and photosensitive resin, adding 15 parts of photosensitive resin is optimal.

[0119] In summary, the resin composition prepared by this invention exhibits excellent performance in terms of bonding strength, chemical resistance, hydrophobicity, and rapid gelation due to the dual effects of hydrogen bonding and chemical crosslinking. It is a product formulation with practical applications, can be quickly positioned, and is suitable for use in more demanding environments.

[0120] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A resin composition with high adhesive strength, characterized in that, The resin composition comprises: (a) Resin: The resin includes one or a combination of epoxy resin and photosensitive resin; (b) Curing agent: The curing agent is a diphenylalkyl ketone polythiol compound having a structure as shown in general formula (I): Among them, R 1 and R 2 Each is independently selected from one of the alkylene groups having 1 to 5 carbon atoms, R 3 Selected from one of the alkylene groups having 0 to 5 carbon atoms; (c) Curing accelerator: When the resin is an epoxy resin, the curing accelerator is an amine; when the resin is a combination of epoxy resin and photosensitive resin, the curing accelerator is a free radical photoinitiator and an amine.

2. The high adhesive strength resin composition according to claim 1, characterized in that, The curing agent has a structure as shown in general formula (II):

3. The high adhesive strength resin composition according to claim 1 or 2, characterized in that, The diphenylalkyl ketone polythiol compound is prepared according to the following steps: (1) Add dihydroxydiphenyl alkyl ketone, first haloolefin compound and first solvent to a reaction vessel, then add first basic catalyst and phase transfer catalyst, and then heat to 60-90℃ under nitrogen atmosphere for 8-15h to obtain first intermediate product; (2) The first intermediate product is added to the reaction vessel and heated to 150-250°C under nitrogen protection for 8-16 hours to obtain the second intermediate product; (3) The second intermediate product, the second haloolefin compound and the second solvent are added to the reaction vessel, and then the second basic catalyst and the phase transfer catalyst are added. The reaction is then heated to 60-90°C under a nitrogen atmosphere for 8-15 hours to obtain the third intermediate product. (4) Add the third intermediate, thioacetic acid, and the third solvent to the reaction vessel, then add the free radical initiator, and then heat to 60-90℃ under a nitrogen atmosphere for 16-25 h to obtain the fourth intermediate. (5) The fourth intermediate and the fourth solvent are added to the reaction vessel and then heated to 60-90°C under a nitrogen atmosphere for 25-35 h to obtain the diphenyl alkyl ketone polythiol compound.

4. The high adhesive strength resin composition according to claim 3, characterized in that, In the method for preparing the diphenylalkyl ketone polythiol compound, the dihydroxy diphenylalkyl ketone is a diphenyl ring linked by an alkyl ketone, each benzene ring containing at least one phenolic hydroxyl group, and its structural formula is as follows: Among them, R 3 It is one of the alkylene groups having 0 to 5 carbon atoms; The first and second haloalkene compounds are respectively selected from alkanes whose molecular chains are capped with bromine or chlorine at one end and double bonds at the other end, and their structures are as follows: Where X represents chlorine or bromine, R 4 It is one of the alkylene groups having 1 to 5 carbon atoms.

5. The high adhesive strength resin composition according to claim 4, characterized in that, The dihydroxydiphenyl ketone is 1,2-bis(4-hydroxyphenyl)ethyl ketone or 4,4'-dihydroxydiphenyl ketone; the first and second haloolefin compounds are allyl bromide or allyl chloride.

6. The high adhesive strength resin composition according to claim 3, characterized in that, The first and second solvents are respectively selected from one or more of acetone, ethanol, dimethyl sulfoxide, and N,N-dimethylformamide; The first and second basic compounds are respectively selected from one or more of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, triethylamine, and p-dimethylaminopyridine; The free radical initiator includes one or more of azo, organic peroxide, and redox initiators; The third and fourth solvents are selected from one or more of acetone, ethyl acetate, tetrahydrofuran, N,N'-dimethylformamide, dichloromethane, dioxane, ethanol, and methanol.

7. The high adhesive strength resin composition according to any one of claims 1 to 6, characterized in that, When the resin is epoxy resin, the resin composition includes 48 to 53 parts by weight of epoxy resin, 32 to 39 parts by weight of diphenyl alkyl ketone polythiol compound curing agent, and 0.1 to 5 parts by weight of amine curing accelerator. When the resin is a combination of epoxy resin and photosensitive resin, the resin composition includes 37-40 parts by weight of epoxy resin, 10-20 parts by weight of photosensitive resin, 25-28 parts by weight of diphenyl alkyl ketone polythiol compound, 1-5 parts by weight of free radical photoinitiator, 1-5 parts by weight of amine curing accelerator, 0.5-3 parts by weight of stabilizer, and 0.1-1 parts by weight of polymerization inhibitor.

8. The high adhesive strength resin composition according to any one of claims 7, characterized in that, It also includes additives, which are selected from at least one of fillers, antioxidants, stabilizers, polymerization inhibitors, flame retardants, adhesion promoters, coupling agents, toughening agents, diluents, pigments, defoamers, leveling agents, wetting agents, homogenizers, and ion trapping agents; the content of the additives is 0.01 to 10 parts by weight.

9. The method for preparing the high adhesive strength resin composition as described in claim 8, characterized in that, The method includes: mixing the resin, diphenyl alkyl ketone polythiol compound, accelerator and additives evenly using a planetary disperser, degassing under vacuum and then filling to obtain the target product.

10. Use of the high adhesive strength resin composition according to any one of claims 1 to 10 as an adhesive, sealant, or coating material for bonding, sealing, or coating electronic components.

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