Preparation method of epoxy resin adhesive

Abstract

The application relates to the technical field of adhesives, and discloses a preparation method of an epoxy resin adhesive. Para-aminophenol is reacted with diphenyl dichlorosilane under the catalysis of triethanolamine to obtain di(para-aminophenoxy)diphenyl silane; the amino groups in the di(para-aminophenoxy)diphenyl silane and the amino groups in polyether amine are subjected to Mannich reaction with formaldehyde and phenol to obtain a silane-containing polyether amine type benzoxazine intermediate. Finally, the silane-containing polyether amine type benzoxazine intermediate and epoxy resin are uniformly mixed, and curing is carried out to obtain the epoxy resin adhesive. The silane-containing polyether amine type benzoxazine intermediate prepared by the method contains a silane structure and a benzoxazine structure, both of which have excellent heat resistance; when the silane-containing polyether amine type benzoxazine intermediate is added to the epoxy resin, the prepared epoxy resin adhesive has excellent heat resistance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of adhesives, in particular to a preparation method of an epoxy resin adhesive. BACKGROUND

[0002] An adhesive is used to connect two or more materials together through the adhesion and cohesion of the interface, and is widely used in various fields of human life. Epoxy resin is a thermosetting resin containing two or more epoxy groups, and has excellent mechanical properties, bonding properties, insulation properties and other properties. The epoxy resin adhesive has low cost, high bonding strength and excellent comprehensive performance, and is widely used in the fields of airplanes, rockets, automobiles and electronics. However, the epoxy resin adhesive has poor high-temperature resistance, and therefore how to improve the heat resistance of the epoxy resin adhesive to expand its application field is one of the current research focuses.

[0003] Benzoxazine is a benzene derivative containing a nitrogen atom and an oxygen atom, and can form a structure similar to a phenolic resin through ring-opening polymerization, and has excellent flame retardance, heat resistance and mechanical properties, and is widely used in the fields of printed circuit boards and aerospace. Silane has excellent mechanical properties, thermal properties and toughness, and is widely used in the fields of microelectronics, machinery, chemical industry and optics. For example, the patent with the authorized announcement number CN113150501B discloses a benzoxazine flame-retardant modified epoxy resin for vacuum infusion molding and a preparation method. The benzoxazine resin, phosphate flame retardant, curing agent and accelerator are added to the epoxy resin to prepare a benzoxazine flame-retardant modified epoxy resin, which has low viscosity and excellent flame retardance, but the heat resistance is not improved. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the deficiencies of the prior art, the application provides a preparation method of an epoxy resin adhesive, and the prepared epoxy resin adhesive has excellent heat resistance.

[0006] (II) Technical scheme

[0007] A preparation method of an epoxy resin adhesive, the preparation method comprises the following steps:

[0008] (1) dissolving p-aminophenol and triethanolamine in tetrahydrofuran solvent, stirring and dispersing, then adding diphenyldichlorosilane into the mixture, and carrying out warming reflux reaction, filtration, water washing, dissolving the mixture in petroleum ether, filtration, recrystallization, and obtaining di(p-aminophenoxy)diphenylsilane, and the reaction equation is as follows .

[0009] (2) The (p-aminophenoxy) diphenyl silane, polyether amine, 30-40% formaldehyde solution is added to the toluene solvent, stirring and dispersing for 40-80 min, then phenol is added, stirring and reacting, rotary evaporation to remove the solvent, water washing, drying to obtain the silane-containing polyether amine type benzoxazine intermediate.

[0010] (3) The silane-containing polyether amine type benzoxazine intermediate and the epoxy resin are mixed uniformly, heated to 80-100 ℃, preheated for 3-5 min, then diamino dimethyl is added, stirring uniformly, vacuum degassing, curing in the drying oven to obtain the epoxy resin adhesive.

[0011] Preferably, the molar ratio of the p-aminophenol, triethanolamine and diphenyl dichlorosilane in step (1) is 1.8-2.4:2-2.6:1.

[0012] Preferably, the reflux reaction time in step (1) is 30-50 h, and the temperature is 60-80 ℃.

[0013] Preferably, the molar ratio of the (p-aminophenoxy) diphenyl silane, polyether amine and phenol in step (2) is 1:0.6-0.8:1.5-2.5.

[0014] Preferably, the stirring reaction time in step (2) is 5-8 h, and the temperature is 20-35 ℃.

[0015] Preferably, the curing process in step (3) is 160-170 ℃ / 1 h, 180-200 ℃ / 1 h, 210-230 ℃ / 1 h.

[0016] Preferably, the mass ratio of the silane-containing polyether amine type benzoxazine intermediate, epoxy resin and 4,4-diamino diphenyl sulfone in step (3) is 0.2-0.6:1:0.8-1.2.

[0017] (Three) Beneficial technical effects

[0018] The p-aminophenol reacts with diphenyl dichlorosilane under the catalysis of triethanolamine to obtain (p-aminophenoxy) diphenyl silane, and the amino group in the (p-aminophenoxy) diphenyl silane and the amino group in the polyether amine undergo Mannich reaction with formaldehyde and phenol to obtain the silane-containing polyether amine type benzoxazine intermediate. Finally, the silane-containing polyether amine type benzoxazine intermediate and the epoxy resin are mixed uniformly, and cured to obtain the epoxy resin adhesive.

[0019] The silane polyether amine type benzoxazine intermediate prepared by the present application contains flexible long chains in the polyether amine, and can form a larger network structure when added into the epoxy resin, so that a larger energy can be absorbed when impacted, so as to increase the mechanical properties of the epoxy resin. The benzoxazine contained therein can absorb a larger amount of heat to undergo ring-opening polymerization when heated, so that a larger network structure similar to the phenolic resin is formed, and more heat is absorbed. When added into the epoxy resin, the heat resistance of the epoxy resin can be increased. The epoxy resin adhesive prepared by the present application has excellent heat resistance. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] Embodiment 1

[0022] (1) 120 mmol of p-aminophenol and 120 mmol of triethanolamine were dissolved in tetrahydrofuran solvent, stirred and dispersed, then 50 mmol of diphenyldichlorosilane was added, heated to 80°C, refluxed for 36 h, filtered, washed with water, then dissolved in petroleum ether, filtered, and recrystallized to obtain diphenylsilane bis(p-aminophenoxy).

[0023] (2) 0.5 mol of diphenylsilane bis(p-aminophenoxy), 0.3 mol of polyether amine, and 35% formaldehyde solution were added to toluene solvent, stirred and dispersed for 60 min, then 0.75 mol of phenol was added, stirred at 25°C for 8 h, the solvent was removed by rotary evaporation, washed with water, and dried to obtain a silane-containing polyether amine type benzoxazine intermediate.

[0024] (3) 10 g of the silane-containing polyether amine type benzoxazine intermediate and 50 g of epoxy resin were uniformly mixed, heated to 100°C, preheated for 4 min, then 50 g of diamino dimethyl methane was added, stirred uniformly, vacuum degassed, and cured in a drying oven, with a curing process of 160°C / 1 h, 180°C / 1 h, and 220°C / 1 h, to obtain an epoxy resin adhesive.

[0025] Embodiment 2

[0026] (1) 90 mmol of p-aminophenol, 130 mmol of triethanolamine were dissolved in tetrahydrofuran solvent, stirred and dispersed, 50 mmol of diphenyldichlorosilane was added thereto, warmed to 70°C, refluxed for 48 h, filtered, washed with water, dissolved in petroleum ether, filtered, recrystallized to obtain di(p-aminophenoxy)diphenylsilane.

[0027] (2) 0.5 mol of di(p-aminophenoxy)diphenylsilane, 0.35 mol of polyetheramine, 30% formaldehyde solution were added to toluene solvent, stirred and dispersed for 50 min, 0.8 mol of phenol was added thereto, stirred at 35°C for 6 h, the solvent was removed by rotary evaporation, washed with water, dried to obtain a silane-containing polyether amine type benzoxazine intermediate.

[0028] (3) 15 g of the silane-containing polyether amine type benzoxazine intermediate, 50 g of epoxy resin were mixed uniformly, warmed to 90°C, preheated for 5 min, 60 g of diaminodimethylmethane was added thereto, stirred uniformly, vacuum degassed, cured in a drying oven, the curing process was 170°C / 1 h, 200°C / 1 h, 230°C / 1 h to obtain an epoxy resin adhesive.

[0029] Example 3

[0030] (1) 100 mmol of p-aminophenol, 110 mmol of triethanolamine were dissolved in tetrahydrofuran solvent, stirred and dispersed, 50 mmol of diphenyldichlorosilane was added thereto, warmed to 80°C, refluxed for 50 h, filtered, washed with water, dissolved in petroleum ether, filtered, recrystallized to obtain di(p-aminophenoxy)diphenylsilane.

[0031] (2) 0.5 mol of di(p-aminophenoxy)diphenylsilane, 0.3 mol of polyetheramine, 40% formaldehyde solution were added to toluene solvent, stirred and dispersed for 40 min, 1.25 mol of phenol was added thereto, stirred at 20°C for 8 h, the solvent was removed by rotary evaporation, washed with water, dried to obtain a silane-containing polyether amine type benzoxazine intermediate.

[0032] (3) 20 g of the silane-containing polyether amine type benzoxazine intermediate, 50 g of epoxy resin were mixed uniformly, warmed to 90°C, preheated for 5 min, 40 g of diaminodimethylmethane was added thereto, stirred uniformly, vacuum degassed, cured in a drying oven, the curing process was 165°C / 1 h, 185°C / 1 h, 215°C / 1 h to obtain an epoxy resin adhesive.

[0033] Example 4

[0034] (1) 120 mmol of p-aminophenol, 100 mmol of triethanolamine were dissolved in tetrahydrofuran solvent, stirred and dispersed, 50 mmol of diphenyldichlorosilane was added thereto, warmed to 70°C, refluxed for 40 h, filtered, washed with water, dissolved in petroleum ether, filtered, recrystallized to obtain di(p-aminophenoxy)diphenylsilane.

[0035] (2) 0.5 mol of di(p-aminophenoxy)diphenylsilane, 0.4 mol of polyetheramine, 30% formaldehyde solution were added to toluene solvent, stirred and dispersed for 80 min, 0.8 mol of phenol was added thereto, stirred at 30°C for 6 h, the solvent was removed by rotary evaporation, washed with water, dried to obtain a silane-containing polyether amine type benzoxazine intermediate.

[0036] (3) 25 g of the silane-containing polyether amine type benzoxazine intermediate, 50 g of epoxy resin were mixed uniformly, warmed to 80°C, preheated for 5 min, 50 g of diaminodimethylmethane was added thereto, stirred uniformly, vacuum degassed, cured in a drying oven, the curing process was 160°C / 1 h, 190°C / 1 h, 220°C / 1 h to obtain an epoxy resin adhesive.

[0037] Example 5

[0038] (1) 120 mmol of p-aminophenol, 100 mmol of triethanolamine were dissolved in tetrahydrofuran solvent, stirred and dispersed, 50 mmol of diphenyldichlorosilane was added thereto, warmed to 80°C, refluxed for 40 h, filtered, washed with water, dissolved in petroleum ether, filtered, recrystallized to obtain di(p-aminophenoxy)diphenylsilane.

[0039] (2) 0.5 mol of di(p-aminophenoxy)diphenylsilane, 0.38 mol of polyetheramine, 30% formaldehyde solution were added to toluene solvent, stirred and dispersed for 80 min, 1 mol of phenol was added thereto, stirred at 30°C for 8 h, the solvent was removed by rotary evaporation, washed with water, dried to obtain a silane-containing polyether amine type benzoxazine intermediate.

[0040] (3) 30 g of the silane-containing polyether amine type benzoxazine intermediate, 50 g of epoxy resin were mixed uniformly, warmed to 90°C, preheated for 4 min, 50 g of diaminodimethylmethane was added thereto, stirred uniformly, vacuum degassed, cured in a drying oven, the curing process was 160°C / 1 h, 190°C / 1 h, 210°C / 1 h to obtain an epoxy resin adhesive.

[0041] Comparative Example 1

[0042] (1) 120 mmol of p-aminophenol and 120 mmol of triethanolamine were dissolved in tetrahydrofuran solvent, stirred and dispersed, 50 mmol of diphenyldichlorosilane was added, heated to 80°C, refluxed for 36 h, filtered, washed with water, then dissolved in petroleum ether, filtered, recrystallized to obtain di(p-aminophenoxy)diphenylsilane.

[0043] (2) 10 g of di(p-aminophenoxy)diphenylsilane and 50 g of epoxy resin were uniformly mixed, heated to 100°C, preheated for 4 min, then 50 g of diamino dimethyl methane was added and stirred uniformly, vacuum degassed, and cured in a drying oven, with a curing process of 160°C / 1 h, 180°C / 1 h, 220°C / 1 h, to obtain an epoxy resin adhesive.

[0044] Comparative Example 2

[0045] (1) 50 g of epoxy resin was uniformly mixed, heated to 100°C, preheated for 4 min, then 50 g of diamino dimethyl methane was added and stirred uniformly, vacuum degassed, and cured in a drying oven, with a curing process of 160°C / 1 h, 180°C / 1 h, 220°C / 1 h, to obtain an epoxy resin adhesive.

[0046] Thermogravimetric analysis: under nitrogen atmosphere, 10°C / min heating rate, temperature range of 30-800°C. T(0%) is the initial decomposition temperature, and T(5%) is the temperature at which 5% of the weight is lost.

[0047]

[0048] As can be seen from the table, the decomposition temperature of Examples 1-5 is higher than that of Comparative Examples 1-2, therefore, the heat resistance of Examples 1-5 is better than that of Comparative Examples 1-2, because the silane-containing polyether amine type benzoxazine intermediate is contained in Examples 1-5, while Comparative Example 1 only contains di(p-aminophenoxy)diphenylsilane, and Comparative Example 2 does not contain the silane-containing polyether amine type benzoxazine intermediate or di(p-aminophenoxy)diphenylsilane, the heat resistance of Comparative Example 1 is not as good as that of Examples 1-5, and the heat resistance of Comparative Example 2 is the worst, therefore, the silane-containing polyether amine type benzoxazine intermediate prepared in the present application can increase the heat resistance of the epoxy resin when added to the epoxy resin.

[0049] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and that the appended claims are intended to cover all such modifications that do not depart from the true spirit and scope of the application. Therefore, the application is not limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an epoxy resin adhesive, characterized in that, The preparation method is as follows: (1) Dissolve p-aminophenol and triethanolamine in tetrahydrofuran solvent, stir and disperse, then add diphenyldichlorosilane, heat and reflux to react, filter, wash with water, then dissolve in petroleum ether, filter, recrystallize to obtain di(p-aminophenoxy)diphenylsilane. (2) Add bis(p-aminophenoxy)diphenylsilane, polyetheramine, and 30-40% formaldehyde solution to toluene solvent, stir and disperse for 40-80 min, add phenol, stir and react, remove solvent by rotary evaporation, wash with water, and dry to obtain silane-containing polyetheramine type benzoxazine intermediate; (3) Mix the silane-containing polyetheramine benzoxazine intermediate and epoxy resin evenly, heat to 80-100 ℃, preheat for 3-5 min, then add diaminodimethyl ether, stir evenly, degas under vacuum, and cure in a drying oven to obtain epoxy resin adhesive.

2. The method for preparing the epoxy resin adhesive according to claim 1, characterized in that, In step (1), the molar ratio of p-aminophenol, triethanolamine, and diphenyldichlorosilane is 1.8-2.4:2-2.6:

1.

3. The method for preparing the epoxy resin adhesive according to claim 1, characterized in that, In step (1), the reflux reaction time is 30-50 hours and the temperature is 60-80℃.

4. The method for preparing the epoxy resin adhesive according to claim 1, characterized in that, In step (2), the molar ratio of bis(p-aminophenoxy)diphenylsilane, polyetheramine, and phenol is 1:0.6-0.8:1.5-2.

5.

5. The method for preparing the epoxy resin adhesive according to claim 1, characterized in that, The stirring reaction time in step (2) is 5-8 hours and the temperature is 20-35℃.

6. The method for preparing the epoxy resin adhesive according to claim 1, characterized in that, The curing process in step (3) is 160-170℃ / 1h, 180-200℃ / 1h, 210-230℃ / 1h.

7. The method for preparing the epoxy resin adhesive according to claim 1, characterized in that, In step (3), the mass ratio of the silane polyetheramine benzoxazine intermediate, epoxy resin, and 4,4-diaminodiphenyl sulfone is 0.2-0.6:1:0.8-1.2.

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