High-strength and high-toughness epoxy glue and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, in particular to high-strength and high-toughness epoxy glue and a preparation method thereof.The high-strength and high-toughness epoxy glue comprises a component A and a component B. The component A and the component B are used in cooperation according to the mass ratio of 1: 1, and the component A comprises, by mass, 80-100 parts of epoxy resin, 10-20 parts of reactive diluent, 30-50 parts of liquid nitrile rubber buna 40 and 40-60 parts of filler; the component B is prepared from the following components in parts by mass: 40 to 60 parts of methylhexahydroanhydride, 0.4 to 0.6 part of PEG (polyethylene glycol)-carboxyl pyrazole copolymer and 40 to 60 parts of filler. According to the invention, the viscosity of the system is reduced by the PEG-carboxyl pyrazole copolymer, so that the epoxy glue is easier to process, coat and level in the use process, the viscosity reduction is beneficial to spreading of a material on a larger surface area, construction is convenient, the material can form a uniform thin-layer structure with a cross-linked network, and the strength and the toughness are improved.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to a high-strength and high-toughness epoxy adhesive and a preparation method thereof. Background Art

[0002] Epoxy adhesive refers to an adhesive made of epoxy resin as the main component and an appropriate amount of epoxy resin curing agent. The fracture energy and fracture toughness of general epoxy resins are poor, and they are not impact-resistant, which greatly limits the application of epoxy resins. In order to improve the brittleness and low toughness of epoxy resins, a certain amount of toughening agent is often added to the epoxy resin and curing agent system.

[0003] CN111073570B discloses a medium-temperature curing high-toughness epoxy adhesive and a preparation method thereof. The invention uses a siloxane hybrid polyurethane elastomer as a toughening agent. The toughening mechanism of the siloxane hybrid polyurethane elastomer is mainly introduced through the flexible segment, but excessive flexible segments may reduce the tensile strength and modulus of the material, resulting in a decrease in the overall mechanical properties of the material. In addition, there are differences in the solubility parameters of polyurethane and siloxane. The introduction of siloxane may make the processing of polyurethane more complicated, and the reaction conditions need to be precisely controlled to ensure the compatibility of siloxane and polyurethane, resulting in a relatively high preparation cost. Summary of the invention

[0004] The object of the present invention is to provide a high-strength and high-toughness epoxy adhesive and a preparation method thereof to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, on the one hand, the present invention provides the following technical solutions: a high-strength and high-toughness epoxy adhesive, comprising component A and component B, wherein component A and component B are used in a mass ratio of 1:1, component A comprises the following components by mass: 80 to 100 parts of epoxy resin, 10 to 20 parts of active diluent, 30 to 50 parts of liquid nitrile rubber-40, and 40 to 60 parts of filler, and component B comprises the following components by mass: 40 to 60 parts of methyl hexahydroanhydride, 0.4 to 0.6 parts of PEG-carboxyl pyrazole copolymer, and 40 to 60 parts of filler;

[0006] The PEG-carboxyl pyrazole copolymer is prepared by the following steps: (1) dissolving PEG and DCC in anhydrous dichloromethane, stirring evenly, and obtaining a PEG solution, wherein the molar ratio of the terminal hydroxyl group of PEG to DCC is 1:1.1; (2) adding carboxyl pyrazole to the PEG solution, and adding DMAP as a catalyst, stirring evenly, and obtaining a mixed solution, wherein the molar ratio of PEG to carboxyl pyrazole is 1:1-1.2; (3) slowly heating the mixed solution to 40-50°C under a nitrogen atmosphere, and continuously stirring for 3-6 hours; (4) cooling the mixed solution to room temperature, adding cold water, and centrifuging to remove insoluble matter to obtain a PEG cross-linked carboxyl pyrazole product.

[0007] Optionally, the epoxy resin is one or a combination of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, and bisphenol F epoxy resin.

[0008] Optionally, the active diluent is one of butyl glycidyl ether, ethylene glycol diglycidyl ether, phenyl glycidyl ether, 1,4-butanediol diglycidyl ether, decyl glycidyl ether, neopentyl glycol diglycidyl ether, and resorcinol diglycidyl ether.

[0009] Optionally, the filler is one or a combination of mica powder, silica powder, ultrafine talc powder, nano calcium carbonate, and glass fiber powder.

[0010] 5. A high-strength and high-toughness epoxy adhesive according to claim 1, characterized in that the mass ratio of methyl hexahydroanhydride to PEG-carboxyl pyrazole copolymer in component B is 100:1, and the mass ratio of methyl hexahydroanhydride to filler in component B is 1:1.

[0011] On the other hand, the present invention provides the following technical solution: a method for preparing a high-strength and high-toughness epoxy adhesive, comprising the following steps:

[0012] S1. Prepare component A: add epoxy resin and liquid nitrile rubber-40 into a stirrer, stir and mix at a speed of 800-1000 r / min for 30-60 min, then add active diluent and filler, stir and mix at a speed of 600-800 r / min for 60-120 min, vacuum degas, filter and package to obtain component A;

[0013] S2, preparing component B: adding methyl hexahydroanhydride and PEG-carboxyl pyrazole copolymer into a stirrer, stirring and mixing at a speed of 800 to 1200 r / min for 30 to 60 min, then adding filler, stirring and mixing at a speed of 600 to 800 r / min for 60 to 120 min, vacuum degassing, filtering and packaging to obtain component B;

[0014] S3, mixing: mixing component A with component B to obtain high-strength and high-toughness epoxy adhesive.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention introduces PEG into carboxyl pyrazole. The introduction of PEG can effectively reduce the intermolecular interaction force of the entire system, thereby reducing the viscosity of the system. The flexible chain structure of PEG allows a larger molecular motion space, reducing the cohesive force of the material. The cross-linked structure of the PEG-carboxyl pyrazole copolymer can act as a molecular lubricant in the mixed system of epoxy resin and methyl hexahydroanhydride, reducing the internal friction of the system and the viscosity increase rate after the A component and the B component are mixed, so that the high-strength and high-toughness epoxy adhesive is easy to pot;

[0017] 2. The PEG-carboxyl pyrazole copolymer in the present invention reduces the viscosity of the system, making the epoxy adhesive easier to process, coat and level during use. The reduced viscosity helps the material to spread over a larger surface area, facilitates construction, and helps the material to form a uniform thin layer structure with a cross-linked network, thereby improving strength and toughness. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Example 1: The present invention provides a high-strength and high-toughness epoxy adhesive, comprising component A and component B. Component A and component B are used in a mass ratio of 1:1. Component A comprises the following components in mass parts: 80 parts of epoxy resin, 10 parts of active diluent, 30 parts of liquid nitrile rubber-40, and 40 parts of filler. Component B comprises the following components in mass parts: 40 parts of methyl hexahydroanhydride, 0.4 parts of PEG-carboxyl pyrazole copolymer, and 40 parts of filler.

[0020] Example 2: The present invention provides a high-strength and high-toughness epoxy adhesive, comprising component A and component B. Component A and component B are used in a mass ratio of 1:1. Component A comprises the following components by mass: 90 parts of epoxy resin, 12 parts of active diluent, 40 parts of liquid nitrile rubber-40, and 50 parts of filler. Component B comprises the following components by mass: 50 parts of methyl hexahydroanhydride, 0.5 parts of PEG-carboxyl pyrazole copolymer, and 50 parts of filler.

[0021] Example 3: The present invention provides a high-strength and high-toughness epoxy adhesive, comprising component A and component B. Component A and component B are used in a mass ratio of 1:1. Component A comprises the following components in mass parts: 90 parts of epoxy resin, 18 parts of active diluent, 45 parts of liquid nitrile rubber-40, and 50 parts of filler. Component B comprises the following components in mass parts: 50 parts of methyl hexahydroanhydride, 0.5 parts of PEG-carboxyl pyrazole copolymer, and 50 parts of filler.

[0022] Example 4: The present invention provides a high-strength and high-toughness epoxy adhesive, comprising component A and component B. Component A and component B are used in a mass ratio of 1:1. Component A comprises the following components in mass parts: 100 parts of epoxy resin, 20 parts of active diluent, 50 parts of liquid nitrile rubber-40, and 60 parts of filler. Component B comprises the following components in mass parts: 60 parts of methyl hexahydroanhydride, 0.6 parts of PEG-carboxyl pyrazole copolymer, and 60 parts of filler.

[0023] In Examples 1 to 4, the epoxy resin is bisphenol A epoxy resin, the active diluent is butyl glycidyl ether, the filler is a combination of mica powder and silica powder, and the mass ratio of mica powder to silica powder is 1:1.

[0024] In Examples 1 to 4, the PEG-carboxyl pyrazole copolymer was prepared by the following steps: (1) dissolving PEG and DCC in anhydrous dichloromethane and stirring to obtain a PEG solution, wherein the molar ratio of the terminal hydroxyl group of PEG to DCC is 1:1.1; (2) adding carboxyl pyrazole to the PEG solution and adding DMAP as a catalyst, stirring to obtain a mixed solution, wherein the molar ratio of PEG to carboxyl pyrazole is 1:1.1; (3) slowly heating the mixed solution to 44° C. under a nitrogen atmosphere and stirring continuously for 4 hours; (4) cooling the mixed solution to room temperature, adding cold water, and centrifuging to remove insoluble matter to obtain a PEG cross-linked carboxyl pyrazole product.

[0025] The present invention also discloses a method for preparing a high-strength and high-toughness epoxy adhesive, comprising the following steps:

[0026] S1. Prepare component A: add epoxy resin and liquid nitrile rubber-40 into a stirrer, stir and mix at a speed of 900 r / min for 45 min, then add active diluent and filler, stir and mix at a speed of 750 r / min for 90 min, vacuum degas, filter and package to obtain component A;

[0027] S2. Prepare component B: add methyl hexahydroanhydride and PEG-carboxyl pyrazole copolymer into a stirrer, stir and mix at a speed of 100 r / min for 45 min, then add filler, stir and mix at a speed of 750 r / min for 90 min, vacuum degas, filter and package to obtain component B;

[0028] S3, mixing: mixing component A with component B to obtain high-strength and high-toughness epoxy adhesive.

[0029] Examples 1 to 4 can all use the above preparation method to prepare the high-strength and high-toughness epoxy adhesive disclosed in the present invention.

[0030] Test Example 1

[0031] Test content: Use a mold to cast the high-strength and high-toughness epoxy adhesive prepared by the above preparation method in Examples 1 to 4 into a dumbbell-shaped specimen of 200mm×10mm×3mm, and use the standard disclosed in "Determination of Tensile Properties of Plastics Part 1: General" (GB / T1040.1-2018) to test on a servo-controlled material testing machine. The test rate is 20mm / min and the test temperature is 25°C. The tensile strength, elongation at break and elastic modulus of the high-strength and high-toughness epoxy adhesive are measured, and the results are recorded in Table 1.

[0032] Test Example 2

[0033] Test content: Use a mold to cast the high-strength and high-toughness epoxy adhesive prepared by the above preparation method in Examples 1 to 4 into a rectangular specimen of 200mm×10mm×3mm, and use the standard disclosed in "Determination of Bending Properties of Plastics" (GB / T 9341-2008) to test on a servo-controlled material testing machine. The test rate is 10mm / min, the test temperature is 25°C, and the bending strength of the high-strength and high-toughness epoxy adhesive is measured. The results are recorded in Table 1.

[0034] Table 1

[0035] Tensile strength / MPa Elongation at break / % Elastic modulus / MPa Bending strength / MPa Example 1 71.2 5.9 1218 102 Example 2 71.6 6.0 1232 107 Example 3 71.9 6.1 1234 109 Example 4 72.8 6.2 1263 115

[0036] As can be seen from Table 1, the high-strength and high-toughness epoxy adhesive prepared by the above preparation method in Example 4 has the best mechanical properties and is worthy of promotion and use.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-strength and high-toughness epoxy adhesive, comprising component A and component B, characterized in that: Component A and component B are used in a mass ratio of 1:

1. Component A includes the following components by mass: 80-100 parts of epoxy resin, 10-20 parts of active diluent, 30-50 parts of liquid nitrile rubber-40, and 40-60 parts of filler. Component B includes the following components by mass: 40-60 parts of methyl hexahydroanhydride, 0.4-0.6 parts of PEG-carboxyl pyrazole copolymer, and 40-60 parts of filler. The PEG-carboxyl pyrazole copolymer is prepared by the following steps: (1) dissolving PEG and DCC in anhydrous dichloromethane, stirring evenly, and obtaining a PEG solution, wherein the molar ratio of the terminal hydroxyl group of PEG to DCC is 1:1.1; (2) adding carboxyl pyrazole to the PEG solution, and adding DMAP as a catalyst, stirring evenly, and obtaining a mixed solution, wherein the molar ratio of PEG to carboxyl pyrazole is 1:1-1.2; (3) slowly heating the mixed solution to 40-50°C under a nitrogen atmosphere, and continuously stirring for 3-6 hours; (4) cooling the mixed solution to room temperature, adding cold water, and centrifuging to remove insoluble matter to obtain a PEG cross-linked carboxyl pyrazole product.

2. A high-strength and high-toughness epoxy adhesive according to claim 1, characterized in that: The epoxy resin is one or a combination of bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, and bisphenol F epoxy resin.

3. A high-strength and high-toughness epoxy adhesive according to claim 1, characterized in that: The active diluent is one of butyl glycidyl ether, ethylene glycol diglycidyl ether, phenyl glycidyl ether, 1,4-butanediol diglycidyl ether, decyl glycidyl ether, neopentyl glycol diglycidyl ether and resorcinol diglycidyl ether.

4. The high-strength and high-toughness epoxy adhesive according to claim 1, characterized in that: The filler is one or a combination of mica powder, silica powder, ultrafine talc powder, nano calcium carbonate and glass fiber powder.

5. The high-strength and high-toughness epoxy adhesive according to claim 1, characterized in that: The mass ratio of methyl hexahydroanhydride to PEG-carboxyl pyrazole copolymer in component B is 100:1, and the mass ratio of methyl hexahydroanhydride to filler in component B is 1:

1.

6. A method for preparing a high-strength and high-toughness epoxy adhesive according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Prepare component A: add epoxy resin and liquid nitrile rubber-40 into a stirrer, stir and mix at a speed of 800-1000 r / min for 30-60 min, then add active diluent and filler, stir and mix at a speed of 600-800 r / min for 60-120 min, vacuum degas, filter and package to obtain component A; S2, preparing component B: adding methyl hexahydroanhydride and PEG-carboxyl pyrazole copolymer into a stirrer, stirring and mixing at a speed of 800 to 1200 r / min for 30 to 60 min, then adding filler, stirring and mixing at a speed of 600 to 800 r / min for 60 to 120 min, vacuum degassing, filtering and packaging to obtain component B; S3, mixing: mixing component A with component B to obtain high-strength and high-toughness epoxy adhesive.