A heat-resistant epoxy resin and preparation method thereof

Abstract

The present invention relates to the technical field of polymer materials, and discloses a heat-resistant epoxy resin and a preparation method thereof. The present invention adds bisphenol A epoxy resin, silicon-containing epoxy resin, and maleimide resin-based benzoxazine into a reactor, stirs, continues to add m-phenylenediamine curing agent, performs curing reaction, stirs, and stands to obtain a high-temperature resistant epoxy resin. The silicon element, phosphorus element, nitrogen element, and benzoxazine structure in the silicon-containing epoxy resin and maleimide resin-based benzoxazine all have good flame retardant effects; and benzoxazine will form a heat-resistant phenolic resin structure at high temperatures, so that it has a good flame retardant effect; the phenolic hydroxyl group in the formed phenolic resin will cross-link and cure with the epoxy group in the bisphenol A epoxy resin and the silicon-containing epoxy resin, thereby improving the compatibility with each other, and the siloxane in the silicon-containing epoxy resin and the maleimide resin in the maleimide resin-based benzoxazine themselves have good heat resistance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a heat-resistant epoxy resin and a preparation method thereof. Background Art

[0002] Epoxy resin is a general term for compounds containing two or more epoxy groups in the molecular structure. Epoxy resin has good mechanical properties, electrical insulation and corrosion resistance, and is widely used in coatings, adhesives, transportation equipment and other fields, so the requirements for its performance are getting higher and higher. For example, patent CN108587068B discloses a hydrophobic flame-retardant epoxy resin and its preparation method. The epoxy resin of the invention has the characteristics of non-toxicity, environmental protection and flame retardancy, and can be used outdoors or in humid and harsh environments, but its heat resistance effect has not been improved. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the deficiencies of the prior art, the present invention provides a heat-resistant epoxy resin and a preparation method thereof, which have good flame retardant and heat-resistant effects.

[0005] (II) Technical solution

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a heat-resistant epoxy resin, comprising the following weight components: 60-80 weight parts of bisphenol A epoxy resin, 14-32 weight parts of silicon-containing epoxy resin, 10-15 weight parts of maleimide resin-based benzoxazine, and 2-4 weight parts of m-phenylenediamine curing agent.

[0007] Preferably, the preparation method of the silicon-containing epoxy resin is:

[0008] (1) Add diphenyltetramethyltrisiloxane to a reactor containing 4,4-(propane-2,2-diyl)bis(2-allylphenol) and dichloromethane, introduce nitrogen protection, add platinum-1,3-divinyltetramethyldisiloxane complex catalyst to the reactor at 0-2°C, and then stir magnetically at 35-50°C for 2-4 hours. After the reaction is completed, remove the solvent by rotary distillation, and vacuum dry to obtain intermediate 1;

[0009] (2) Add acetone solvent to the reactor, pass nitrogen protection, add intermediate 1 and phosphorus oxychloride, react at 35-50°C for 6-10 hours, add ice water after the reaction, concentrate, add ethyl acetate for extraction, dry the organic phase over anhydrous magnesium sulfate, concentrate the filtrate, wash with ether, and then recrystallize with ethyl acetate to obtain intermediate 2;

[0010] (3) adding intermediate 2 and 4-hydroxymethyl caged bicyclic phosphate to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 80-120° C. for 8-13 h, and then removing the solvent by distillation under reduced pressure, filtering and drying to obtain olefinic phosphate;

[0011] (4) Add the olefinic phosphate to N,N-dimethylformamide solvent, stir evenly, then add aqueous hydrogen peroxide solution, react at 25-40° C. for 3-6 hours, and then distill under reduced pressure, filter and dry to obtain a silicon-containing epoxy resin.

[0012] Preferably, the mass ratio of diphenyltetramethyltrisiloxane, 4,4-(propane-2,2-diyl)bis(2-allylphenol), and platinum-1,3-divinyltetramethyldisiloxane complex catalyst in (1) is 1:1.1-1.3:0.01-0.04.

[0013] Preferably, the mass ratio of the intermediate 1 to phosphorus oxychloride in (2) is 1.2-1.5:1.

[0014] Preferably, the mass ratio of the intermediate 2 to the 4-hydroxymethyl caged bicyclic phosphate in (3) is 1:1.6-1.8.

[0015] Preferably, the mass ratio of olefinated phosphate ester to aqueous hydrogen peroxide solution in (4) is 1:2.1-2.8.

[0016] Preferably, the preparation method of the maleimide resin-based benzoxazine is:

[0017] S1. 4-10 parts by weight of bismaleimide resin and 5-12 parts by weight of intermediate 1 are added to a reactor, stirred and mixed, heated to 110-130 ° C and stirred for 12-16 min, and then cooled to room temperature to obtain a phenol-based maleimide resin;

[0018] S2. Add 7-15 parts by weight of 4,4-diaminodiphenyl sulfone, 20-30 parts by weight of an aqueous solution of formaldehyde, and 10-16 parts by weight of a phenol-based maleimide resin into a toluene solvent, fully dissolve them, and carry out a cyclization reaction. The reaction is carried out at 60-90°C for 10-15 hours. After the reaction, the mixture is distilled under reduced pressure, washed with deionized water, and the crude product is recrystallized from dichloromethane to obtain maleimide resin-based benzoxazine.

[0019] Preferably, the preparation method of the heat-resistant epoxy resin is: add bisphenol A epoxy resin, silicon-containing epoxy resin, and maleimide resin-based benzoxazine into a reactor, stir, continue to add m-phenylenediamine curing agent, perform curing reaction at 65-80°C for 2-4h, stir, and stand to obtain a high temperature resistant epoxy resin.

[0020] 3. Beneficial technical effects

[0021] The invention provides a high temperature resistant epoxy resin by adding bisphenol A epoxy resin, silicon-containing epoxy resin and maleimide resin-based benzoxazine into a reactor, stirring, continuously adding metaphenylenediamine curing agent, performing curing reaction, stirring and standing.

[0022] The silicon, phosphorus, nitrogen and benzoxazine structures in silicon-containing epoxy resin and maleimide resin-based benzoxazine all have good flame retardant effects. The nitrogen element produces non-flammable gas when burning, which can dilute the flammable gas in the air and hinder the combustion. The silicon element contained in it can form a glass-like substance on the surface of the material when burning, which hinders the material transfer and energy transport between the air and the substrate. The phosphorus element contained in it can generate polyphosphoric acid and metaphosphoric acid with strong dehydration properties, which dehydrates and carbonizes the material. Since polyphosphoric acid and metaphosphoric acid are not easy to volatilize, they can form a dense protective layer on the polymer surface. Thus, a flame retardant effect is achieved; intermediate 1 is further grafted with 4-hydroxymethyl cage-like bicyclic phosphate by reacting with phosphorus oxychloride, thereby increasing its degree of substitution and having a good flame retardant effect, and benzoxazine will form a heat-resistant phenolic resin structure at high temperature, so that it has a good flame retardant effect; the phenolic hydroxyl groups in the formed phenolic resin will cross-link and cure with the epoxy groups in the bisphenol A epoxy resin and the silicon-containing epoxy resin, thereby increasing the compatibility with each other and forming a curing system with meta-phenylenediamine; the siloxane in the silicon-containing epoxy resin and the maleimide resin in the maleimide resin-based benzoxazine themselves have good heat resistance. DETAILED DESCRIPTION Example 1

[0023] (1) Add diphenyltetramethyltrisiloxane to a reactor containing 4,4-(propane-2,2-diyl)bis(2-allylphenol) and dichloromethane, introduce nitrogen protection, add platinum-1,3-divinyltetramethyldisiloxane complex catalyst to the reactor at 0°C, wherein the mass ratio of diphenyltetramethyltrisiloxane, 4,4-(propane-2,2-diyl)bis(2-allylphenol) and platinum-1,3-divinyltetramethyldisiloxane complex catalyst is 1:1.1:0.01, and then stir magnetically at 35°C for 2 hours. After the reaction is completed, remove the solvent by rotary distillation, and dry in vacuo to obtain intermediate 1;

[0024] (2) Add acetone solvent to the reactor, pass nitrogen protection, add intermediate 1 and phosphorus oxychloride, wherein the mass ratio of intermediate 1 to phosphorus oxychloride is 1.2:1, react at 35°C for 6 hours, add ice water after the reaction, concentrate, add ethyl acetate for extraction, dry the organic phase over anhydrous magnesium sulfate, concentrate the filtrate, wash with ether, and then recrystallize with ethyl acetate to obtain intermediate 2;

[0025] (3) adding intermediate 2 and 4-hydroxymethyl caged bicyclic phosphate to N,N-dimethylformamide solvent, wherein the mass ratio of intermediate 2 to 4-hydroxymethyl caged bicyclic phosphate is 1:1.6, stirring to dissolve, reacting at 80°C for 8h, and then removing the solvent by reduced pressure distillation, filtering and drying to obtain olefinated phosphate;

[0026] (4) adding the olefinic phosphate to N,N-dimethylformamide solvent, stirring evenly, and then adding an aqueous hydrogen peroxide solution thereto, wherein the mass ratio of the olefinic phosphate to the aqueous hydrogen peroxide solution is 1:2.1, reacting at 25° C. for 3 h, and then distilling under reduced pressure, filtering and drying to obtain a silicon-containing epoxy resin;

[0027] (5) 4 parts by weight of bismaleimide resin and 5 parts by weight of intermediate 1 were added to a reactor, stirred and mixed, heated to 110° C., stirred and reacted for 12 min, and then cooled to room temperature to obtain a phenol-based maleimide resin;

[0028] (6) adding 7 parts by weight of 4,4-diaminodiphenyl sulfone, 20 parts by weight of an aqueous solution of formaldehyde, and 10 parts by weight of a phenol-based maleimide resin into a toluene solvent, fully dissolving them, and carrying out a cyclization reaction at 60° C. for 10 hours. After the reaction, the mixture is distilled under reduced pressure, washed with deionized water, and the crude product is recrystallized from dichloromethane to obtain a maleimide resin-based benzoxazine;

[0029] (7) Add 60 parts by weight of bisphenol A epoxy resin, 14 parts by weight of silicon-containing epoxy resin, and 10 parts by weight of maleimide resin-based benzoxazine into a reactor and stir. Continue to add 2 parts by weight of m-phenylenediamine curing agent and carry out curing reaction at 65° C. for 2 hours. Stir and let stand to obtain a high temperature resistant epoxy resin. Example 2

[0030] (1) Add diphenyltetramethyltrisiloxane to a reactor containing 4,4-(propane-2,2-diyl)bis(2-allylphenol) and dichloromethane, introduce nitrogen protection, add platinum-1,3-divinyltetramethyldisiloxane complex catalyst to the reactor at 2°C, wherein the mass ratio of diphenyltetramethyltrisiloxane, 4,4-(propane-2,2-diyl)bis(2-allylphenol) and platinum-1,3-divinyltetramethyldisiloxane complex catalyst is 1:1.3:0.04, and then stir magnetically at 50°C for 4 hours. After the reaction is completed, remove the solvent by rotary distillation, and dry in vacuo to obtain intermediate 1;

[0031] (2) Add acetone solvent to the reactor, pass nitrogen protection, add intermediate 1 and phosphorus oxychloride, wherein the mass ratio of intermediate 1 to phosphorus oxychloride is 1.5:1, react at 50°C for 10 hours, add ice water after the reaction, concentrate, add ethyl acetate for extraction, dry the organic phase over anhydrous magnesium sulfate, concentrate the filtrate, wash with ether, and then recrystallize with ethyl acetate to obtain intermediate 2;

[0032] (3) adding intermediate 2 and 4-hydroxymethyl caged bicyclic phosphate to N,N-dimethylformamide solvent, wherein the mass ratio of intermediate 2 to 4-hydroxymethyl caged bicyclic phosphate is 1:1.8, stirring to dissolve, reacting at 120° C. for 13 h, and then removing the solvent by distillation under reduced pressure, filtering and drying to obtain olefinated phosphate;

[0033] (4) adding the olefinic phosphate to N,N-dimethylformamide solvent, stirring evenly, and then adding an aqueous hydrogen peroxide solution thereto, wherein the mass ratio of the olefinic phosphate to the aqueous hydrogen peroxide solution is 1:2.8, reacting at 40° C. for 6 h, and then distilling under reduced pressure after the reaction, filtering and drying to obtain a silicon-containing epoxy resin;

[0034] (5) 10 parts by weight of bismaleimide resin and 12 parts by weight of intermediate 1 were added to a reactor, stirred and mixed, heated to 130° C., stirred and reacted for 16 minutes, and then cooled to room temperature to obtain a phenol-based maleimide resin;

[0035] (6) adding 15 parts by weight of 4,4-diaminodiphenyl sulfone, 30 parts by weight of an aqueous solution of formaldehyde, and 16 parts by weight of a phenol-based maleimide resin into a toluene solvent, fully dissolving them, and carrying out a cyclization reaction at 90° C. for 15 hours. After the reaction, the mixture was distilled under reduced pressure, washed with deionized water, and the crude product was recrystallized from dichloromethane to obtain a maleimide resin-based benzoxazine;

[0036] (7) Add 80 parts by weight of bisphenol A epoxy resin, 32 parts by weight of silicon-containing epoxy resin, and 15 parts by weight of maleimide resin-based benzoxazine into a reactor and stir. Continue to add 4 parts by weight of m-phenylenediamine curing agent and carry out curing reaction at 80° C. for 4 hours. Stir and let stand to obtain a high temperature resistant epoxy resin. Example 3

[0037] (1) Add diphenyltetramethyltrisiloxane to a reactor containing 4,4-(propane-2,2-diyl)bis(2-allylphenol) and dichloromethane, introduce nitrogen protection, add platinum-1,3-divinyltetramethyldisiloxane complex catalyst to the reactor at 1°C, wherein the mass ratio of diphenyltetramethyltrisiloxane, 4,4-(propane-2,2-diyl)bis(2-allylphenol) and platinum-1,3-divinyltetramethyldisiloxane complex catalyst is 1:1.2:0.025, and then stir magnetically at 45°C for 3 hours. After the reaction is completed, remove the solvent by rotary distillation, and dry in vacuum to obtain intermediate 1;

[0038] (2) Add acetone solvent to the reactor, pass nitrogen protection, add intermediate 1 and phosphorus oxychloride, wherein the mass ratio of intermediate 1 to phosphorus oxychloride is 1.4:1, react at 40°C for 8 hours, add ice water after the reaction, concentrate, add ethyl acetate for extraction, dry the organic phase over anhydrous magnesium sulfate, concentrate the filtrate, wash with ether, and then recrystallize with ethyl acetate to obtain intermediate 2;

[0039] (3) adding intermediate 2 and 4-hydroxymethyl caged bicyclic phosphate to N,N-dimethylformamide solvent, wherein the mass ratio of intermediate 2 to 4-hydroxymethyl caged bicyclic phosphate is 1:1.7, stirring to dissolve, reacting at 100° C. for 10 h, and then removing the solvent by reduced pressure distillation after reaction, filtering and drying to obtain olefinated phosphate;

[0040] (4) adding the olefinic phosphate to N,N-dimethylformamide solvent, stirring evenly, and then adding an aqueous hydrogen peroxide solution thereto, wherein the mass ratio of the olefinic phosphate to the aqueous hydrogen peroxide solution is 1:2.5, reacting at 30° C. for 5 h, and then distilling under reduced pressure after the reaction, filtering and drying to obtain a silicon-containing epoxy resin;

[0041] (5) 7 parts by weight of bismaleimide resin and 8 parts by weight of intermediate 1 were added to a reactor, stirred and mixed, heated to 120° C., stirred and reacted for 14 minutes, and then cooled to room temperature to obtain a phenol-based maleimide resin;

[0042] (6) Add 13 parts by weight of 4,4-diaminodiphenyl sulfone, 25 parts by weight of an aqueous solution of formaldehyde, and 13 parts by weight of a phenol-based maleimide resin into a toluene solvent, fully dissolve them, and carry out a cyclization reaction at 75° C. for 12 hours. After the reaction, distill under reduced pressure, wash with deionized water, and recrystallize the crude product from dichloromethane to obtain a maleimide resin-based benzoxazine;

[0043] (7) Add 70 parts by weight of bisphenol A epoxy resin, 25 parts by weight of silicon-containing epoxy resin, and 13 parts by weight of maleimide resin-based benzoxazine into a reactor and stir. Continue to add 3 parts by weight of m-phenylenediamine curing agent and carry out curing reaction at 72° C. for 3 hours. Stir and let stand to obtain a high temperature resistant epoxy resin.

[0044] Comparative Example 1

[0045] 70 parts by weight of bisphenol A epoxy resin and 13 parts by weight of maleimide resin-based benzoxazine were added to the reactor and stirred. 3 parts by weight of m-phenylenediamine curing agent were added and the curing reaction was carried out at 72° C. for 3 hours. The reaction was stirred and allowed to stand to obtain a high temperature resistant epoxy resin.

[0046] Comparative Example 2

[0047] 70 parts by weight of bisphenol A epoxy resin and 25 parts by weight of silicon-containing epoxy resin are added into a reactor and stirred. 3 parts by weight of m-phenylenediamine curing agent are added continuously. The curing reaction is carried out at 72° C. for 3 hours. The reaction is stirred and allowed to stand to obtain a high temperature resistant epoxy resin.

[0048] The oxygen index of high temperature resistant epoxy resin is tested by oxygen index tester, and the combustion grade of high temperature resistant epoxy resin is tested by horizontal and vertical combustion tester.

[0049] Table 1: Flame retardancy tests.

[0050] project Oxygen index (%) UL-94 Example 1 31 V-0 Example 2 33 V-0 Example 3 30 V-0 Comparative Example 1 22 V-1 Comparative Example 2 21 V-1

[0051] It can be seen from Table 1 that Examples 1-3 of the present invention have better flame retardant effects than Comparative Examples 1-2.

[0052] Glass transition temperature: Dynamic thermomechanical analysis was used to determine the variation of loss factor (tanδ) with temperature in the temperature range of 30 to 350°C in a liquid nitrogen atmosphere and film stretching mode. The heating rate was 5°C / min and the test frequency was 10 Hz, so as to determine the glass transition temperature of the resin composition after curing. The sample size was 42 mm × 8 mm × 0.3 mm.

[0053] Table 2: Heat resistance test.

[0054] project Glass transition temperature (℃) Example 1 258.4 Example 2 267.1 Example 3 249.6 Comparative Example 1 167.4 Comparative Example 2 152.9

[0055] It can be seen from Table 2 that Examples 1-3 of the present invention have better heat resistance than Comparative Examples 1-2.

[0056] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A heat-resistant epoxy resin, characterized in that: The invention comprises the following components by weight: 60-80 parts by weight of bisphenol A epoxy resin, 14-32 parts by weight of silicon-containing epoxy resin, 10-15 parts by weight of maleimide resin-based benzoxazine, and 2-4 parts by weight of m-phenylenediamine curing agent; The preparation method of the silicon-containing epoxy resin is: (1) Add diphenyltetramethyltrisiloxane to a reactor containing 4,4-(propane-2,2-diyl)bis(2-allylphenol) and dichloromethane, introduce nitrogen protection, add platinum-1,3-divinyltetramethyldisiloxane complex catalyst to the reactor at 0-2°C, and then stir magnetically at 35-50°C for 2-4 hours. After the reaction is completed, remove the solvent by rotary distillation, and vacuum dry to obtain intermediate 1; (2) Add acetone solvent to the reactor, pass nitrogen protection, add intermediate 1 and phosphorus oxychloride, react at 35-50°C for 6-10 hours, add ice water after the reaction, concentrate, add ethyl acetate for extraction, dry the organic phase over anhydrous magnesium sulfate, concentrate the filtrate, wash with ether, and then recrystallize with ethyl acetate to obtain intermediate 2; (3) adding intermediate 2 and 4-hydroxymethyl caged bicyclic phosphate to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 80-120° C. for 8-13 h, and then removing the solvent by distillation under reduced pressure, filtering and drying to obtain olefinic phosphate; (4) adding the olefinic phosphate ester to N,N-dimethylformamide solvent, stirring evenly, then adding aqueous hydrogen peroxide solution thereto, reacting at 25-40° C. for 3-6 hours, and then distilling under reduced pressure, filtering and drying to obtain a silicon-containing epoxy resin; The mass ratio of diphenyltetramethyltrisiloxane, 4,4-(propane-2,2-diyl)bis(2-allylphenol), and platinum-1,3-divinyltetramethyldisiloxane complex catalyst in (1) is 1:1.1-1.3:0.01-0.04; The mass ratio of the intermediate 1 to phosphorus oxychloride in (2) is 1.2-1.5:1; The mass ratio of the intermediate 2 and the 4-hydroxymethyl caged bicyclic phosphate in (3) is 1:1.6-1.8; The mass ratio of olefinated phosphate to aqueous hydrogen peroxide solution in (4) is 1:2.1-2.8; The preparation method of the maleimide resin-based benzoxazine is: S1. 4-10 parts by weight of bismaleimide resin and 5-12 parts by weight of intermediate 1 are added to a reactor, stirred and mixed, heated to 110-130 ° C and stirred for 12-16 min, and then cooled to room temperature to obtain a phenol-based maleimide resin; S2. Add 7-15 parts by weight of 4,4-diaminodiphenyl sulfone, 20-30 parts by weight of an aqueous solution of formaldehyde, and 10-16 parts by weight of a phenol-based maleimide resin into a toluene solvent, fully dissolve them, and carry out a cyclization reaction. The reaction is carried out at 60-90°C for 10-15 hours. After the reaction, the mixture is distilled under reduced pressure, washed with deionized water, and the crude product is recrystallized from dichloromethane to obtain maleimide resin-based benzoxazine.

2. A method for preparing a heat-resistant epoxy resin as claimed in claim 1, characterized in that: The preparation method of the heat-resistant epoxy resin is as follows: bisphenol A epoxy resin, silicon-containing epoxy resin, and maleimide resin-based benzoxazine are added into a reactor, stirred, and then m-phenylenediamine curing agent is added, and a curing reaction is carried out at 65-80° C. for 2-4 hours, and then stirred and allowed to stand to obtain a high-temperature resistant epoxy resin.