High-thermal-conductivity adhesive for electronic packaging and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, in particular to a high-thermal-conductivity adhesive for electronic packaging and a preparation method thereof. The high-thermal-conductivity adhesive for electronic packaging is prepared from the following components in parts by weight: 55 to 60 parts of acrylate monomer, 40 to 45 parts of methacrylate monomer, 0.5 to 5 parts of photoinitiator, 10 to 25 parts of modified boron nitride, 1 to 3 parts of thixotropic agent, 0.2 to 1 part of defoaming agent and 0.5 to 1 part of antioxidant. The methacrylate monomer with a novel structure is introduced into the adhesive, so that the adhesive is endowed with excellent hydrolysis resistance, the volume shrinkage of the adhesive is effectively reduced, and the heat-conducting property of the adhesive can be improved. In addition, modified boron nitride is introduced into the adhesive, so that agglomeration of boron nitride can be avoided, the dispersity and compatibility of boron nitride are improved, and the heat-conducting property of the adhesive is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to an adhesive for high thermal conductivity electronic packaging and a preparation method thereof. Background Art

[0002] In the current UV / EB curing industry, HDDA (1,6-hexanediol diacrylate) and TPGDA (tripropylene glycol diacrylate) are the most commonly used base monomers in industrial formulations. While these two short-chain difunctional monomers are highly reactive and inexpensive, they also have significant drawbacks: their cured films typically have glass transition temperatures exceeding 30°C, making them susceptible to brittle cracking under low-temperature bending conditions. Their high double bond density leads to volume shrinkage rates of 6-10%, which can easily cause internal stress, warping, and even cracking. To lower the Tg or shrinkage, plasticizers or polymer diluents are often added, but this can lead to increased VOCs, decreased cure rates, and even fluctuations in physical properties.

[0003] To address these issues, research both domestically and internationally has attempted to modify long-chain dimerized aliphatic raw materials. However, related Chinese patents are mostly limited to the use of "dimer acid" or its polyester and polyurethane derivatives. CN101544721A uses dimer acid to prepare a water-resistant acrylic emulsion. While this improves flexibility, the emulsion formula contains a large number of ester bonds and emulsifiers, resulting in a dark color, high acid value, and limited hydrolytic stability. CN118146478A further end-capsulates dimer acid polyester with isocyanate to produce a polyurethane acrylate. However, due to the presence of urea / urethane bonds, this polyurethane acrylate faces the risk of yellowing and hydrolysis after wet-heat aging. Therefore, the development of a flexible and hydrophobic reactive monomer is crucial.

[0004] In addition, improving the thermal conductivity of adhesives is crucial to the field of electronic packaging. High thermal conductivity helps dissipate heat from devices and improve reliability, and has become one of the important directions in the current development of high-performance adhesives. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, one of the objectives of the present invention is to provide a high thermal conductivity adhesive for electronic packaging. The present invention introduces a synthetic methacrylate monomer with a novel structure and modified boron nitride into the adhesive formula, which gives the adhesive excellent hydrolysis resistance, effectively reduces its volume shrinkage, and significantly improves the thermal conductivity of the adhesive.

[0006] A second object of the present invention is to provide a method for preparing a high thermal conductivity adhesive for electronic packaging, which is simple and easy to implement and has important significance in industrial production applications.

[0007] One of the purposes of the present invention is achieved by the following technical solution: A high thermal conductivity adhesive for electronic packaging, comprising, by weight, 55-60 parts of an acrylate monomer, 40-45 parts of a methacrylate monomer, 0.5-5 parts of a photoinitiator, 10-25 parts of a modified boron nitride, 1-3 parts of a thixotropic agent, 0.2-1 parts of a defoaming agent, and 0.5-1 parts of an antioxidant; The preparation process of the modified boron nitride is as follows: Boron nitride is dispersed in a sodium hydroxide solution, treated under nitrogen protection, washed, and dried to obtain hydroxyboron nitride. The hydroxyboron nitride is then dispersed in a solvent, 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one and a sodium hydroxide solution are added and heated for reaction. After the reaction is completed, the pH of the reaction solution is adjusted to neutral, filtered, washed, and dried to obtain modified boron nitride.

[0008] Furthermore, the usage ratio of the boron nitride and the sodium hydroxide solution is 1-3 g:15-30 mL; the usage ratio of the 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one, hydroxyboron nitride, solvent and sodium hydroxide solution is 1 g:3.0-3.2 g:30-35 mL:0.6-0.8 mL, the solvent is acetone; and the concentration of the sodium hydroxide solution is 5 mol / L.

[0009] Furthermore, the treatment temperature is 90-100° C. and the time is 11-12 hours; the heating reaction temperature is 70-75° C. and the time is 4-6 hours.

[0010] Furthermore, the preparation process of the methacrylate monomer is as follows: (1) Under nitrogen protection, 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boric acid, K2CO3 and PdCl2 were added to a DMF aqueous solution for heating reaction. After the reaction was completed, the reaction solution was extracted, washed and recrystallized to obtain intermediate 1; (2) Under nitrogen protection, 7-bromo-1-heptanol, intermediate 1, K2CO3 and PdCl2 were added to a DMF aqueous solution for heating reaction. After the reaction was completed, the reaction solution was extracted, washed and recrystallized to obtain intermediate 2; (3) The intermediate 2, methacrylic acid, p-toluenesulfonic acid and dibutylhydroxytoluene are added to a toluene solution of DMF for reaction. The reaction solution is cooled and the pH is adjusted to neutral. The reaction solution is distilled, washed and dried to obtain a methacrylate monomer.

[0011] Further, in step (1), the 4-(bromomethyl)benzene boronic acid, 5-furfuryl alcohol-2-boronic acid, K2CO3, PdCl2, DMF aqueous solution are used in a ratio of 5mmol:5-5.5mmol:5.5-6.5mmol:0.5-2mmol:10-15mL; the DMF aqueous solution is obtained by mixing DMF and deionized water in a volume ratio of 10:(0.5-1); the heating reaction temperature is 45-50 DEG C, and the time is 18-24h.

[0012] Further, in step (2), the 7-bromo-1-heptanol, intermediate 1, K2CO3, PdCl2, DMF aqueous solution are used in a ratio of 5mmol:5-5.5mmol:5.5-6.5mmol:0.5-2mmol:12-15mL; the DMF aqueous solution is obtained by mixing DMF and deionized water in a volume ratio of 10:(0.5-1); the heating reaction temperature is 45-50 DEG C, and the time is 18-24h.

[0013] Further, in step (3), the intermediate 2, methacrylic acid, p-toluenesulfonic acid, dibutyl hydroxytoluene and DMF toluene solution are used in a ratio of 5g:1.8-2g:0.03-0.08g:0.003-0.03g:10-15mL; the DMF toluene solution is obtained by mixing DMF and toluene in a volume ratio of 1:(1-2); the reaction temperature is 90-120 DEG C, and the time is 4-8h.

[0014] Further, the acrylate monomer is tripropyleneglycol diacrylate or 1,6-hexanediol diacrylate; the photoinitiator is benzoin dimethyl ether; the thixotropic agent is fumed silica; the defoaming agent is defoaming agent BYK-1790; and the antioxidant is at least one of antioxidant 1010, antioxidant 1072 or antioxidant 1024.

[0015] The second object of the application is achieved by the following technical scheme: The preparation method of the high-thermal-conductivity electronic packaging adhesive comprises the following steps: uniformly mixing acrylate monomers, methacrylate monomers, modified boron nitride, thixotropic agents, defoaming agents and antioxidants, then adding a photoinitiator, vacuumizing to-0.1~-0.08MPa, pressure-maintaining stirring for 3-5h, vacuum defoaming and discharging, and thus the high-thermal-conductivity electronic packaging adhesive is obtained.

[0016] Compared with the prior art, the application has the following advantages: 1. To address the pain points of short-chain diacrylates, which suffer from high Tg, high shrinkage, and poor hydrolysis resistance, this invention synthesizes a hydrophobic diol containing a flexible alkyl chain and a benzene ring structure through a Suzuki coupling reaction, which is then converted into a methacrylate monomer through an esterification reaction. The amorphous long-chain aliphatic hydrocarbon backbone in this monomer is flexible and hydrophobic, imparting an extremely low glass transition temperature (Tg) to the adhesive, excellent hydrolysis resistance, and effectively reducing its volume shrinkage. Furthermore, the rigid conjugated benzene rings introduced into the structure help promote phonon transmission, which has a positive effect on improving the thermal conductivity of the adhesive.

[0017] 2. This invention also introduces modified boron nitride to improve the thermal conductivity of the adhesive. Boron nitride itself serves as a highly thermally conductive backbone, while organic molecules grafted via the reaction of 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one with hydroxyboron nitride effectively optimize interfacial heat transfer performance. The trifluoromethylsulfonyl (-SO2CF3) and carbonyl (C=O) groups introduced into the modified boron nitride have strong polarity and can form hydrogen bonds or dipole interactions with the acrylate matrix. This not only helps to reduce aggregation of the modified boron nitride, improving its dispersibility and compatibility, thereby reducing the thermal resistance of the polymer-filler interface. Furthermore, the strong electronegativity of the trifluoromethylsulfonyl group can induce local polarization of the acrylate molecular chain, promoting the formation of a more ordered microstructure and reducing the interference of disordered thermal vibrations on phonon transmission. In addition, the aromatic structure of indanone can produce a π-π stacking effect with the benzene ring in the methacrylate monomer, further enhancing the coupling and transmission efficiency of phonons at the interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 1 is a comparative infrared spectrum of the modified boron nitride and boron nitride obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0019] Below, in conjunction with the accompanying drawings and specific embodiments, the present invention is further described. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form new embodiments. Specific conditions not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are conventional products obtained through commercial channels.

[0020] Example 1 A high-thermal-conductivity adhesive for electronic packaging comprises, by weight, 58 parts of an acrylate monomer (tripropylene glycol diacrylate), 42 parts of a methacrylate monomer, 3 parts of a photoinitiator (benzoin dimethyl ether), 20 parts of a modified boron nitride, 2 parts of a thixotropic agent (fumed silica), 0.6 parts of a defoamer (defoamer BYK-1790), and 0.8 parts of an antioxidant (antioxidant 1010).

[0021] The preparation process of the modified boron nitride is as follows: Boron nitride powder is dispersed in a 5 mol / L sodium hydroxide solution, wherein the amount ratio of the boron nitride powder to the sodium hydroxide solution is 2 g:25 mL; after treating at 95° C. for 12 hours under nitrogen protection, the mixture is washed and dried to obtain hydroxyboron nitride; the hydroxyboron nitride is then dispersed in acetone, 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one is added, and after dissolution, a 5 mol / L sodium hydroxide solution is added, wherein the amount ratio of 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one, hydroxyboron nitride, acetone and sodium hydroxide solution is 1 g:3.1 g:33 mL:0.7 mL; after reacting at 72° C. for 5 hours, the pH of the reaction solution is adjusted to neutral, the reaction solution is filtered, washed with acetone, and vacuum dried to obtain modified boron nitride.

[0022] The infrared spectrum of modified boron nitride is as follows Figure 1 As shown. Figure 1 It can be seen that the modified boron nitride has a peak at 1725 cm -1 、1205cm -1 and 1065cm -1 The characteristic absorption peaks of C=O, S=O and CF appear at , indicating that the boron nitride modification is successful.

[0023] The preparation process of the methacrylate monomer is as follows: (1) Under nitrogen protection, 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boric acid, K2CO3 and PdCl2 were added to DMF aqueous solution (V DMF :V 去离子水 =10:1), the ratio of 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boronic acid, K2CO3, PdCl2, and DMF aqueous solution was 5 mmol:5.2 mmol:6 mmol:1.3 mmol:13 mL; after reacting at 48°C for 20 h, the reaction solution was extracted with deionized water and ethyl acetate, and the resulting organic phase was washed with deionized water and recrystallized from n-hexane / ethyl acetate to obtain intermediate 1 (yield 73.4%). Intermediate 1 1 HNMR: (C 16 H 27BO3, 400MHz, DMSO-d6) δ: 0.86-0.95 (m, 6H), 1.17-1.33 (m, 6H), 1.38-1.42 (m, 4H), 1.86-1.90 (m, H), 2.33-2 .37 (m, H), 2.58-2.62 (m, H), 3.38-3.42 (m, H), 4.2 (s, 2H), 4.8 (s, H), 7.19-7.21 (d, 2H), 7.74-7.76 (d, 2H). MS (ESI) m / z=278.21[M].

[0024] (2) Under nitrogen protection, 7-bromo-1-heptanol, intermediate 1, K2CO3 and PdCl2 were added to DMF aqueous solution (V DMF :V 去离子水 =10:1), the amount ratio of 7-bromo-1-heptanol, intermediate 1, K2CO3, PdCl2, and DMF aqueous solution is 5mmol:5.2mmol:6mmol:1.3mmol:14mL; after reacting at 48°C for 20h, the reaction solution was extracted with deionized water and ethyl acetate, and the obtained organic phase was washed with deionized water and recrystallized from n-hexane / ethyl acetate to obtain intermediate 2 (yield 71.8%); intermediate 2 1 HNMR: (C 23 H 40 O2, 400MHz, DMSO- d6 ) δ: 0.86-0.95 (m, 6H), 1.17-1.34 (m, 10H), 1.38-1.45 (m, 6H), 1.56-1.65 (m, 4H), 1.86-1.90 (m, H), 2.33 -2.37(m,H), 2.57-2.62(m,3H), 3.38-3.42(m,H), 3.60-3.64(t,2H), 4.7(s,H), 4.8(s,H), 7.05(m,4H). MS (ESI) m / z=348.30[M].

[0025] (3) Add intermediate 2, methacrylic acid, p-toluenesulfonic acid and polymerization inhibitor butylated hydroxytoluene (BHT) to a toluene solution of DMF (v / v, 1:1). The amount ratio of intermediate 2, methacrylic acid, p-toluenesulfonic acid, butylated hydroxytoluene and toluene solution of DMF is 5g:1.9g:0.05g:0.02g:13mL. After reacting at 110℃ for 6h, the reaction solution is cooled to 70℃ and a 10wt% sodium bicarbonate aqueous solution is added to adjust the pH of the solution to neutral. The solvent and water are removed by distillation under reduced pressure, the mixture is washed with deionized water and dried under vacuum to obtain methacrylate monomer (yield 78.9%). 1 HNMR: (C31 H 48 O4, 400MHz, DMSO- d6 ) δ: 0.86-0.95 (m, 6H), 1.17-1.34 (m, 10H), 1.41-1.51 (m, 6H), 1.58-1.65 (m, 4H), 1.86-1.90 (m, H), 2.01 (s, 6H), 2.33-2.37 (m, H), 2.57-2.62 (m, 3H), 3.95-3.99 (t, 2H), 4.45-4.50 (m, H), 6.39-6.41 (m, 2H), 6.47-6.49 (m, 2H), 7.05 (m, 4H). MS (ESI) m / z=484.36 [M].

[0026] This embodiment also provides a method for preparing the above-mentioned high thermal conductivity electronic packaging adhesive, comprising the following steps: sequentially adding the acrylate monomer, methacrylate monomer, modified boron nitride, thixotropic agent, defoaming agent, and antioxidant into a double planetary stirring kettle and mixing them evenly; then adding a photoinitiator; evacuating to -0.1 MPa; maintaining the pressure and stirring for 4 hours; vacuum defoaming; and discharging the material to obtain the high thermal conductivity electronic packaging adhesive.

[0027] Example 2 A high thermal conductivity adhesive for electronic packaging, comprising, by weight, 55 parts of an acrylate monomer (tripropylene glycol diacrylate), 40 parts of a methacrylate monomer, 1 part of a photoinitiator (benzoin dimethyl ether), 10 parts of modified boron nitride, 1 part of a thixotropic agent (fumed silica), 0.2 parts of a defoamer (defoamer BYK-1790), and 0.5 parts of an antioxidant (antioxidant 1072).

[0028] The preparation process of the modified boron nitride is as follows: Boron nitride powder is dispersed in a 5 mol / L sodium hydroxide solution, wherein the amount ratio of the boron nitride powder to the sodium hydroxide solution is 1 g:15 mL; after treating at 90° C. for 11 hours under nitrogen protection, the mixture is washed and dried to obtain hydroxyboron nitride; the hydroxyboron nitride is then dispersed in acetone, 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one is added, dissolved, and then a 5 mol / L sodium hydroxide solution is added, wherein the amount ratio of 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one, hydroxyboron nitride, acetone, and sodium hydroxide solution is 1 g:3.0 g:30 mL:0.6 mL; after reacting at 70° C. for 6 hours, the pH of the reaction solution is adjusted to neutral, the reaction solution is filtered, washed with acetone, and dried in vacuo to obtain modified boron nitride.

[0029] The preparation process of the methacrylate monomer is as follows: (1) Under nitrogen protection, 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boric acid, K2CO3 and PdCl2 were added to DMF aqueous solution (V DMF :V 去离子水 =10:1), the amount ratio of 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boronic acid, K2CO3, PdCl2, and DMF aqueous solution is 5mmol:5mmol:5.5mmol:0.5mmol:10mL; after reacting at 45℃ for 24h, the reaction solution was extracted with deionized water and ethyl acetate, and the obtained organic phase was washed with deionized water and recrystallized from n-hexane / ethyl acetate to obtain intermediate 1 (yield 71.6%); intermediate 1 1 The HNMR and MS (ESI) m / z characterization results were the same as in Example 1.

[0030] (2) Under nitrogen protection, 7-bromo-1-heptanol, intermediate 1, K2CO3 and PdCl2 were added to DMF aqueous solution (V DMF :V 去离子水 =10:1), the amount ratio of 7-bromo-1-heptanol, intermediate 1, K2CO3, PdCl2, and DMF aqueous solution is 5mmol:5mmol:5.5mmol:0.5mmol:12mL; after reacting at 45°C for 24h, the reaction solution was extracted with deionized water and ethyl acetate, and the obtained organic phase was washed with deionized water and recrystallized from n-hexane / ethyl acetate to obtain intermediate 2 (yield 70.2%); intermediate 2 1 The HNMR and MS (ESI) m / z characterization results were the same as in Example 1.

[0031] (3) Intermediate 2, methacrylic acid, p-toluenesulfonic acid and polymerization inhibitor BHT were added to a toluene solution of DMF (v / v, 1:1). The amount ratio of intermediate 2, methacrylic acid, p-toluenesulfonic acid, dibutylhydroxytoluene and toluene solution of DMF was 5g:1.8g:0.03g:0.003g:10mL. After reacting at 90°C for 8h, the reaction solution was cooled to 60°C and a 10wt% sodium bicarbonate aqueous solution was added to adjust the pH of the solution to neutral. The solvent and water were removed by distillation under reduced pressure, the mixture was washed with deionized water and dried under vacuum to obtain a methacrylate monomer (yield 76.5%). 1 The HNMR and MS (ESI) m / z characterization results were the same as in Example 1.

[0032] This embodiment also provides a method for preparing a high thermal conductivity adhesive for electronic packaging, comprising the following steps: adding an acrylate monomer, a methacrylate monomer, a modified boron nitride, a thixotropic agent, a defoaming agent, and an antioxidant to a double planetary stirring kettle in sequence and mixing them evenly, then adding a photoinitiator, evacuating to -0.08 MPa, maintaining the pressure and stirring for 3 hours, vacuum defoaming, and discharging the material to obtain the high thermal conductivity adhesive for electronic packaging.

[0033] Example 3 A high thermal conductivity adhesive for electronic packaging, comprising, by weight, 60 parts of an acrylate monomer (1,6-hexanediol diacrylate), 45 parts of a methacrylate monomer, 5 parts of a photoinitiator (benzoin dimethyl ether), 25 parts of modified boron nitride, 3 parts of a thixotropic agent (fumed silica), 1 part of a defoaming agent (defoaming agent BYK-1790), and 1 part of an antioxidant (antioxidant 1024).

[0034] The preparation process of the modified boron nitride is as follows: Boron nitride powder is dispersed in a 5 mol / L sodium hydroxide solution, wherein the amount ratio of the boron nitride powder to the sodium hydroxide solution is 3 g:30 mL; after treating at 100° C. for 11 hours under nitrogen protection, the mixture is washed and dried to obtain hydroxyboron nitride; the hydroxyboron nitride is then dispersed in acetone, 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one is added, and after dissolution, a 5 mol / L sodium hydroxide solution is added, wherein the amount ratio of 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one, hydroxyboron nitride, acetone and sodium hydroxide solution is 1 g:3.2 g:35 mL:0.8 mL; after reacting at 75° C. for 4 hours, the pH of the reaction solution is adjusted to neutral, the reaction solution is filtered, washed with acetone, and vacuum dried to obtain modified boron nitride.

[0035] The preparation process of the methacrylate monomer is as follows: (1) Under nitrogen protection, 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boric acid, K2CO3 and PdCl2 were added to DMF aqueous solution (V DMF :V 去离子水 =10:1), the amount ratio of 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boronic acid, K2CO3, PdCl2, and DMF aqueous solution is 5mmol:5.5mmol:6.5mmol:2mmol:15mL; after reacting at 50℃ for 24h, the reaction solution was extracted with deionized water and ethyl acetate, and the obtained organic phase was washed with deionized water and recrystallized from n-hexane / ethyl acetate to obtain intermediate 1 (yield 72.8%); intermediate 1 1 The HNMR and MS (ESI) m / z characterization results were the same as in Example 1.

[0036] (2) Under nitrogen protection, 7-bromo-1-heptanol, intermediate 1, K2CO3 and PdCl2 were added to DMF aqueous solution (V DMF :V 去离子水 =10:1), the amount ratio of 7-bromo-1-heptanol, intermediate 1, K2CO3, PdCl2, and DMF aqueous solution is 5mmol:5.5mmol:6.5mmol:2mmol:15mL; after reacting at 50°C for 18h, the reaction solution was extracted with deionized water and ethyl acetate, and the obtained organic phase was washed with deionized water and recrystallized from n-hexane / ethyl acetate to obtain intermediate 2 (yield 71.4%); intermediate 2 1 The HNMR and MS (ESI) m / z characterization results were the same as in Example 1.

[0037] (3) Intermediate 2, methacrylic acid, p-toluenesulfonic acid and polymerization inhibitor BHT were added to a toluene solution of DMF (v / v, 1:1). The amount ratio of intermediate 2, methacrylic acid, p-toluenesulfonic acid, dibutylhydroxytoluene and toluene solution of DMF was 5g:2g:0.08g:0.03g:15mL. After reacting at 120℃ for 4h, the reaction solution was cooled to 80℃ and a 10wt% sodium bicarbonate aqueous solution was added to adjust the pH of the solution to neutral. The solvent and water were removed by distillation under reduced pressure, the product was washed with deionized water and dried under vacuum to obtain methacrylate monomer (yield 78.1%). 1 The HNMR and MS (ESI) m / z characterization results were the same as in Example 1.

[0038] This embodiment also provides a method for preparing a high thermal conductivity adhesive for electronic packaging, comprising the following steps: adding an acrylate monomer, a methacrylate monomer, a modified boron nitride, a thixotropic agent, a defoaming agent, and an antioxidant to a double planetary stirring kettle in sequence and mixing them evenly, then adding a photoinitiator, evacuating to -0.1 MPa, maintaining the pressure and stirring for 5 hours, vacuum defoaming, and discharging the material to obtain the high thermal conductivity adhesive for electronic packaging.

[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that boron nitride is used instead of modified boron nitride, and the other aspects are the same as those of Example 1.

[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that tripropylene glycol diacrylate is used to replace the methacrylate monomer, and the other aspects are the same as those of Example 1.

[0041] Test example (1) Shear Strength: The adhesives obtained in Examples 1-3 and Comparative Examples 1-2 were cured between glass panels under irradiation with a 340 nm wavelength, 80 W UV lamp for 120 s. The thickness of the adhesive film was 0.15 mm. Shear strength was tested according to GB / T7124-2008.

[0042] (2) Hydrolysis resistance: The adhesives obtained in Examples 1-3 and Comparative Examples 1-2 were cured between glass (curing conditions were the same as above) and then stored at 85°C and 95% relative humidity for 1000 h. Shear strength was tested according to GB / T7124-2008. The hydrolysis resistance of the adhesives was evaluated by the shear strength after high temperature and high humidity.

[0043] (3) Volume shrinkage: The volume shrinkage of the adhesive is tested in accordance with the test standard ISO3521:1997.

[0044] (4) Water absorption rate: After the adhesive is cured between the glass and the glass (curing conditions are the same as above), it is immersed in deionized water at 25°C for 72 hours and the water absorption rate of the film is calculated.

[0045] (5) Thermal conductivity: Refer to the test standard GB / T10297-2015 for thermal conductivity testing.

[0046] (6) Determine the glass transition temperature (Tg) using a differential scanning calorimeter. The samples of Examples 1-3 and Comparative Examples 1 and 2 were equilibrated at -80°C, maintained at this temperature for 2 min, and then heated to melt at a rate of 10°C / min. The peak temperature at which the sample transitioned from the glassy state to the liquid state was recorded as the glass transition temperature (Tg).

[0047] Table 1 From the test results in Table 1, it can be seen that the adhesives obtained in Examples 1-3 of the present invention have good shear strength, excellent hydrolysis resistance, and can effectively reduce volume shrinkage, thereby improving the thermal conductivity of the adhesive.

[0048] Compared with Example 1, Comparative Example 1 uses boron nitride to replace modified boron nitride, and the hydrolysis resistance, water absorption, volume shrinkage, and thermal conductivity of the adhesive all show varying degrees of reduction; Comparative Example 2 uses tripropylene glycol diacrylate to replace the methacrylate monomer, and the thermal conductivity of the adhesive is significantly reduced, indicating that the thermal conductivity of the adhesive has deteriorated.

[0049] In summary, the present invention, through the introduction of a newly synthesized methacrylate monomer, imparts excellent hydrolysis resistance to the adhesive, effectively reduces its volume shrinkage, and improves its thermal conductivity. Furthermore, the modified boron nitride introduced into the adhesive reduces boron nitride aggregation, improves its dispersibility and compatibility, and further enhances the adhesive's thermal conductivity.

[0050] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A high thermal conductivity adhesive for electronic packaging, characterized in that: The high thermal conductivity electronic packaging adhesive comprises, by weight: 55-60 parts of acrylate monomer, 40-45 parts of methacrylate monomer, 0.5-5 parts of photoinitiator, 10-25 parts of modified boron nitride, 1-3 parts of thixotropic agent, 0.2-1 parts of defoaming agent and 0.5-1 parts of antioxidant; The preparation process of the modified boron nitride is as follows: Boron nitride is dispersed in a sodium hydroxide solution, treated under nitrogen protection, washed, and dried to obtain hydroxyboron nitride. The hydroxyboron nitride is then dispersed in a solvent, 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one and a sodium hydroxide solution are added and heated for reaction. After the reaction is completed, the pH of the reaction solution is adjusted to neutral, filtered, washed, and dried to obtain modified boron nitride.

2. The high thermal conductivity electronic packaging adhesive according to claim 1, characterized in that: The usage ratio of the boron nitride and the sodium hydroxide solution is 1-3 g:15-30 mL; the usage ratio of the 4-bromo-2,3-dihydro-7-[(trifluoromethyl)sulfonyl]-1H-inden-1-one, hydroxyboron nitride, solvent and sodium hydroxide solution is 1 g:3.0-3.2 g:30-35 mL:0.6-0.8 mL, the solvent is acetone; and the concentration of the sodium hydroxide solution is 5 mol / L.

3. The high thermal conductivity electronic packaging adhesive according to claim 1, characterized in that: The treatment temperature is 90-100° C. and the time is 11-12 hours; the heating reaction temperature is 70-75° C. and the time is 4-6 hours.

4. The high thermal conductivity electronic packaging adhesive according to claim 1, characterized in that: The preparation process of the methacrylate monomer is as follows: (1) Under nitrogen protection, 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boric acid, K2CO3 and PdCl2 were added to a DMF aqueous solution for heating reaction. After the reaction was completed, the reaction solution was extracted, washed and recrystallized to obtain intermediate 1; (2) Under nitrogen protection, 7-bromo-1-heptanol, intermediate 1, K2CO3 and PdCl2 were added to a DMF aqueous solution for heating reaction. After the reaction was completed, the reaction solution was extracted, washed and recrystallized to obtain intermediate 2; (3) The intermediate 2, methacrylic acid, p-toluenesulfonic acid and dibutylhydroxytoluene are added to a toluene solution of DMF for reaction. The reaction solution is cooled and the pH is adjusted to neutral. The reaction solution is distilled, washed and dried to obtain a methacrylate monomer.

5. The high thermal conductivity electronic packaging adhesive according to claim 4, characterized in that: In step (1), the dosage ratio of the 4-(bromomethyl)phenylboronic acid, 5-furfuryl-2-boric acid, K2CO3, PdCl2, and DMF aqueous solution is 5 mmol: 5-5.5 mmol: 5.5-6.5 mmol: 0.5-2 mmol: 10-15 mL; the DMF aqueous solution is obtained by mixing DMF and deionized water in a volume ratio of 10: (0.5-1); the heating reaction temperature is 45-50 ° C, and the time is 18-24 h.

6. The high thermal conductivity electronic packaging adhesive according to claim 4, characterized in that: In step (2), the usage ratio of 7-bromo-1-heptanol, intermediate 1, K2CO3, PdCl2, and DMF aqueous solution is 5 mmol: 5-5.5 mmol: 5.5-6.5 mmol: 0.5-2 mmol: 12-15 mL; the DMF aqueous solution is obtained by mixing DMF and deionized water in a volume ratio of 10: (0.5-1); the heating reaction temperature is 45-50 ° C, and the time is 18-24 h.

7. The high thermal conductivity electronic packaging adhesive according to claim 4, characterized in that: In step (3), the amount ratio of the intermediate 2, methacrylic acid, p-toluenesulfonic acid, dibutylhydroxytoluene and DMF toluene solution is 5g:1.8-2g:0.03-0.08g:0.003-0.03g:10-15mL; the DMF toluene solution is obtained by mixing DMF and toluene in a volume ratio of 1:(1-2); the reaction temperature is 90-120°C, and the reaction time is 4-8h.

8. The high thermal conductivity electronic packaging adhesive according to claim 1, characterized in that: The acrylate monomer is tripropylene glycol diacrylate or 1,6-hexanediol diacrylate; the photoinitiator is benzoin dimethyl ether; the thixotropic agent is fumed silica; the defoaming agent is defoaming agent BYK-1790; and the antioxidant is at least one of antioxidant 1010, antioxidant 1072, or antioxidant 1024.

9. The method for preparing the adhesive for high thermal conductivity electronic packaging according to any one of claims 1 to 8, characterized in that: The following steps are involved: Acrylate monomer, methacrylate monomer, modified boron nitride, thixotropic agent, defoaming agent and antioxidant are uniformly mixed, and then a photoinitiator is added. The mixture is evacuated to -0.1 to -0.08 MPa, stirred at the pressure for 3 to 5 hours, and then vacuum defoamed and discharged to obtain the high thermal conductivity electronic packaging adhesive.

Images