Epoxy adhesive with high-temperature-resistant function and preparation process thereof

Abstract

The invention relates to the technical field of adhesives, and discloses an epoxy adhesive with a high-temperature-resistant function and a preparation process thereof.The epoxy adhesive comprises the following raw materials: epoxy resin, a diluent, a defoaming agent, a curing agent, an accelerant, a modified composite additive component and an antioxidant, the epoxy adhesive is prepared by preparing the modified composite additive component and adding the modified composite additive component into the epoxy resin matrix, so that the prepared epoxy adhesive has excellent bonding performance, high temperature resistance and toughness and can be firmly connected with an adhered base material, and the durability and reliability of the adhesive are ensured; according to the present invention, the thermal motion of the molecular chain can be limited in the high temperature environment, such that the molecular chain is not easily broken, the stable performance is maintained, the stress can be absorbed and dispersed, the impact energy can be consumed, the cracking and shedding phenomena can be avoided, and the application range of the epoxy adhesive can be broadened.

Description

Technical Field

[0001] The present invention relates to the technical field of adhesives, and in particular to an epoxy adhesive with high temperature resistance functionality and a manufacturing process thereof. Background Art

[0002] With the continuous advancement of science and technology and the rapid development of society, adhesives are also playing an important role in all walks of life. Epoxy adhesives, also known as epoxy resin adhesives, can bond with a variety of substrates such as metal, glass, plastic, wood, etc., and are called universal adhesives. Epoxy adhesives have excellent chemical stability, low curing shrinkage, excellent dimensional stability of the adhesive layer, not prone to creep, excellent electrical insulation performance, easy processing and molding, and are relatively environmentally friendly and pollution-free. They are widely used in the bonding, repair and assembly of various parts in the fields of automobiles, electronics, aerospace, transportation, etc. Therefore, the research and modification of epoxy adhesives are of great practical significance.

[0003] Ordinary epoxy adhesives still have many shortcomings. Epoxy resins are not tough enough. When subjected to external impact, they may crack or fall off. In addition, epoxy resins have poor high temperature resistance. In high temperature environments, thermal decomposition may occur, molecular chains may break, and cross-linking density may decrease, resulting in decreased adhesive performance, deformation, cracking or falling off, which greatly shortens the service life of epoxy adhesives and affects product reliability and safety. These problems limit the use of epoxy adhesives. Patent No. CN111253896B discloses an epoxy adhesive and a preparation method thereof. , application, the adhesive includes an epoxy resin component and a curing agent component, the epoxy resin component includes an epoxy resin containing a long-chain hydrocarbon group and a polyurethane group, a low-viscosity flexible epoxy resin, and a coupling agent a; the curing agent component includes polythiol, monoalcohol amine, tertiary amine urea, coupling agent b and a defoaming agent. The prepared adhesive is suitable for occasions requiring rapid fixing at room temperature or low temperature, and has a short fixing time and high toughness. However, the epoxy adhesive does not take into account the application in a high temperature environment. Therefore, the present invention provides an epoxy adhesive with high temperature resistance functionality, which also has excellent performance in a high temperature environment and has broad application prospects. Summary of the invention

[0004] In order to solve the problems mentioned in the background technology, the purpose of the present invention is to provide an epoxy adhesive with high temperature resistance functionality and a manufacturing process thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions: An epoxy adhesive with high temperature resistance functionality comprises the following raw materials in parts by weight: 80-110 parts of epoxy resin, 5-10 parts of diluent, 1-3 parts of defoamer, 4-10 parts of curing agent, 0.5-3.5 parts of accelerator, 3-6 parts of modified composite additive components, and 0.4-2 parts of antioxidant.

[0006] Furthermore, the epoxy resin is bisphenol A epoxy resin or bisphenol F epoxy resin; the diluent is any one of 2-glycidyl ether, polypropylene glycol diglycidyl ether or o-cresol glycidyl ether; the defoamer is dimethyl silicone oil; the curing agent is any one of 4-4'diaminodiphenyl sulfone, dicyandiamide or 4-4'diaminodiphenylmethane; the accelerator is 2-methylimidazole or 2-ethyl-4-methylimidazole; the antioxidant is antioxidant 1010 or antioxidant 1098.

[0007] Furthermore, the preparation method of the modified composite additive component comprises the following steps: Step A: Preparation of modified brucite fiber The brucite fiber is added to N,N-dimethylformamide, and ultrasonically dispersed to form a uniform suspension, maleic rosin and a catalyst are added to the suspension, the temperature is raised to 85-95° C., and the mixture is stirred and reacted for 4-5 hours. After cooling to room temperature, the mixture is filtered, washed, and dried to obtain the modified brucite fiber. By adopting the above technical solution, the surface of the brucite fiber contains hydroxyl groups, which can react with the acid anhydride in the maleic rosin structure under the action of high temperature and catalyst to obtain modified brucite fiber with carboxyl groups.

[0008] Step B, preparation of modified rubber Add the hydroxy-terminated polyisoprene rubber to xylene, stir evenly, add halogenated anthracene and potassium carbonate solution, introduce nitrogen protection and raise the temperature to 70-85°C, react for 3-5 hours, cool and separate the product to obtain modified rubber; By adopting the above technical scheme, the hydroxyl groups in the hydroxyl-terminated polyisoprene rubber structure can undergo substitution reaction with the halogen elements in the halogenated anthracene structure under the action of potassium carbonate to obtain modified rubber.

[0009] Step C: Preparation of modified composite additive components The modified brucite fiber is added into dimethyl sulfoxide, and ultrasonically dispersed to form a uniform suspension. The modified rubber and the composite catalyst are added into the suspension, and after stirring for 6-8 hours, the mixture is centrifuged, washed and dried to obtain a modified composite additive component.

[0010] By adopting the above technical scheme, the carboxyl groups on the surface of the modified brucite fiber can undergo an esterification reaction with the hydroxyl groups in the modified rubber structure under the action of the composite catalyst, thereby achieving an organic combination of the brucite fiber and the rubber, and obtaining a modified composite additive component.

[0011] Furthermore, in step A, the catalyst is p-toluenesulfonic acid.

[0012] Furthermore, in step B, the number average molecular weight of the hydroxyl-terminated polyisoprene rubber is 2000.

[0013] Furthermore, in step B, the halogenated anthracene is 9-chloromethylanthracene or 9-bromomethylanthracene.

[0014] Furthermore, in step B, the molar ratio of the hydroxyl-terminated polyisoprene rubber to the halogenated anthracene is 1:0.8-1.

[0015] Furthermore, in step C, the composite catalyst is dicyclohexylcarbodiimide and N-hydroxysuccinimide in a mass ratio of 0.6-1:0.1-0.3.

[0016] A process for preparing an epoxy adhesive having high temperature resistance functionality comprises the following steps: Step 1: adding epoxy resin, diluent, defoamer, modified composite additive component and antioxidant into a high-speed mixer, mixing and stirring for 50-80 minutes to obtain a mixture; Step 2: Add curing agent and accelerator to the mixture, raise the temperature to 60-90°C, stir at a stirring rate of 200-500 r / min for 2-5 hours, and cool to room temperature to obtain the epoxy adhesive.

[0017] Beneficial effects of the present invention: (1) The modified composite additive component prepared by the present invention is coated with a flexible interface phase after organic modification of the brucite fiber, which can improve the compatibility problem between the brucite fiber and the epoxy resin matrix, reduce the tendency of the brucite fiber to agglomerate, and help the brucite fiber to be stably and evenly dispersed in the matrix. When subjected to external impact, the brucite fiber can better transmit stress, induce silver streaks, stop crack propagation, consume a large amount of impact energy, and have a toughening effect. At the same time, the polyisoprene rubber in the modified composite additive component contains a flexible chain segment, which can absorb and disperse stress when subjected to external force, thereby achieving the purpose of toughening the matrix. In addition, the modified composite additive component contains unreacted carboxyl groups, which can participate in the curing process of the epoxy resin and generate entanglement crosslinking with the matrix, further improving the toughness of the adhesive and avoiding cracking and falling off when the adhesive is subjected to external impact.

[0018] (2) The brucite fiber in the modified composite additive component has good heat resistance. It can be evenly dispersed in the matrix to form a physical barrier layer, which hinders the rapid transfer of heat. At the same time, the thick aliphatic ring structure of maleic rosin and the rigid anthracene ring introduced in the modified rubber, as well as the cross-linked network structure formed between the modified composite additive component and the matrix, can limit the thermal motion of the chain segments in a high temperature environment, making the molecular chain less likely to break or decompose, thereby enhancing the high temperature resistance of the adhesive and avoiding the performance degradation of the adhesive in a high temperature environment, softening, deformation and shedding, which will shorten the service life of the adhesive.

[0019] (3) The maleic rosin in the modified composite additive component can improve the wettability of the matrix, allowing the adhesive to better penetrate into the tiny pores of the bonded substrate and form a tighter bonding interface. In addition, the modified composite additive component forms a cross-linked network structure with the matrix, which improves the cohesive force, thereby giving the adhesive excellent bonding properties and forming a firm connection with the bonded substrate, ensuring the durability and reliability of the adhesive.

[0020] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0022] Figure 1 This is the infrared spectrum of the modified composite additive component of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0024] The preparation method of the modified composite additive component in the following examples and comparative examples comprises the following steps: Step A: Preparation of modified brucite fiber 4.2 g of brucite fiber was added to N,N-dimethylformamide, and ultrasonically dispersed to form a uniform suspension. 1.5 g of maleic rosin and 0.6 g of p-toluenesulfonic acid were added to the suspension, and the temperature was raised to 90° C., and the mixture was stirred and reacted for 5 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain modified brucite fiber. Step B, preparation of modified rubber 4.2 g of hydroxy-terminated polyisoprene rubber with a number average molecular weight of 2000 was added to xylene, and after being stirred evenly, 0.4 g of 9-chloromethylanthracene and 0.3 g of potassium carbonate solution were added, nitrogen was introduced for protection, and the temperature was raised to 80° C. After reacting for 4 hours, the product was separated by cooling to obtain a modified rubber; Step C: Preparation of modified composite additive components 3.6 g of modified brucite fiber was added to dimethyl sulfoxide, and ultrasonic dispersion was performed to form a uniform suspension. 1.3 g of modified rubber, 0.6 g of dicyclohexylcarbodiimide and 0.1 g of N-hydroxysuccinimide were added to the suspension. After stirring for 7 hours, the mixture was centrifuged, washed and dried to obtain a modified composite additive component.

[0025] The potassium bromide tablet method was used to prepare the sample, and the modified composite additive components were tested by infrared using a Nicolet is5 Fourier transform infrared spectrometer. Figure 1 As shown, the spectral wavenumber test range is 4000cm -1 -500cm -1 , the analysis shows that in the infrared spectrum of the modified composite additive component, 3055cm -1 The absorption peak of the carbon-carbon double bond CH appeared at 3020 cm -1 The absorption peak of benzene ring CH appeared at 1740 cm -1 The absorption peak of ester group C=O appeared at 1710cm -1 The absorption peak of carbonyl C=O appeared at 1122 cm -1 The absorption peak of ether bond COC appeared at 1033 cm -1 The absorption peak of Si-O-Si appears at 968cm -1 There is a Si-O absorption peak at 890 cm -1 、725cm -1 、605cm -1 The absorption peak of anthracene appeared at Example

[0026] Production process of epoxy adhesive Step 1: add 80g of bisphenol A epoxy resin, 5g of polypropylene glycol diglycidyl ether, 1g of dimethyl silicone oil, 3g of modified composite additive components and 0.4g of antioxidant 1010 into a high-speed mixer, mix and stir for 50 minutes to obtain a mixture; Step 2: Add 4 g of 4-4'-diaminodiphenylmethane and 0.5 g of 2-ethyl-4-methylimidazole to the mixture, raise the temperature to 60° C., stir at a stirring rate of 200 r / min for 2 h, and cool to room temperature to obtain an epoxy adhesive. Example

[0027] Production process of epoxy adhesive Step 1: add 90g of bisphenol A epoxy resin, 6g of polypropylene glycol diglycidyl ether, 2g of dimethyl silicone oil, 4g of modified composite additive components and 1g of antioxidant 1010 into a high-speed mixer, mix and stir for 60 minutes to obtain a mixture; Step 2: Add 6 g of 4-4'-diaminodiphenylmethane and 1.5 g of 2-ethyl-4-methylimidazole to the mixture, raise the temperature to 70° C., stir at a stirring rate of 300 r / min for 3 h, and cool to room temperature to obtain an epoxy adhesive. Example

[0028] Production process of epoxy adhesive Step 1: Add 95g of bisphenol A epoxy resin, 6g of polypropylene glycol diglycidyl ether, 2g of dimethyl silicone oil, 5g of modified composite additive components and 1g of antioxidant 1010 into a high-speed mixer, mix and stir for 70 minutes to obtain a mixture; Step 2: Add 8 g of 4-4'-diaminodiphenylmethane and 2 g of 2-ethyl-4-methylimidazole to the mixture, raise the temperature to 80° C., stir at a stirring rate of 400 r / min for 4 h, and cool to room temperature to obtain an epoxy adhesive. Example

[0029] Production process of epoxy adhesive Step 1: add 110 g of bisphenol A epoxy resin, 10 g of polypropylene glycol diglycidyl ether, 3 g of dimethyl silicone oil, 6 g of modified composite additive component and 2 g of antioxidant 1010 into a high-speed mixer, mix and stir for 80 minutes to obtain a mixture; Step 2: Add 10 g of 4-4'-diaminodiphenylmethane and 3.5 g of 2-ethyl-4-methylimidazole to the mixture, raise the temperature to 90° C., stir at a stirring rate of 500 r / min for 5 h, and cool to room temperature to obtain an epoxy adhesive.

[0030] Comparative Example 1 Production process of epoxy adhesive Step 1: Add 95 g of bisphenol A epoxy resin, 6 g of polypropylene glycol diglycidyl ether, 2 g of dimethyl silicone oil, 5 g of brucite fiber and 1 g of antioxidant 1010 into a high-speed mixer, and mix and stir for 70 minutes to obtain a mixture; Step 2: Add 8 g of 4-4'-diaminodiphenylmethane and 2 g of 2-ethyl-4-methylimidazole to the mixture, raise the temperature to 80° C., stir at a stirring rate of 400 r / min for 4 h, and cool to room temperature to obtain an epoxy adhesive.

[0031] Comparative Example 2 Production process of epoxy adhesive Step 1: Add 95 g of bisphenol A epoxy resin, 6 g of polypropylene glycol diglycidyl ether, 2 g of dimethyl silicone oil, 5 g of hydroxyl-terminated polyisoprene rubber and 1 g of antioxidant 1010 into a high-speed mixer, mix and stir for 70 minutes to obtain a mixture; Step 2: Add 8 g of 4-4'-diaminodiphenylmethane and 2 g of 2-ethyl-4-methylimidazole to the mixture, raise the temperature to 80° C., stir at a stirring rate of 400 r / min for 4 h, and cool to room temperature to obtain an epoxy adhesive.

[0032] Comparative Example 3 Production process of epoxy adhesive Step 1: Add 95 g of bisphenol A epoxy resin, 6 g of polypropylene glycol diglycidyl ether, 2 g of dimethyl silicone oil and 1 g of antioxidant 1010 into a high-speed mixer, and mix and stir for 70 minutes to obtain a mixture; Step 2: Add 8 g of 4-4'-diaminodiphenylmethane and 2 g of 2-ethyl-4-methylimidazole to the mixture, raise the temperature to 80° C., stir at a stirring rate of 400 r / min for 4 h, and cool to room temperature to obtain an epoxy adhesive.

[0033] Performance Testing The epoxy adhesives prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were coated on the surface of tinplate, cured at 100°C for 2h, and then cured at 120°C for 1h, and then cooled to room temperature to obtain samples and tested. A 180° peel strength test was performed with reference to standard GB / T 2792-2014 to determine the bonding performance of the epoxy adhesive. After the samples were placed at 150°C for 5h, a 180° peel strength test was performed again to determine the high temperature resistance of the epoxy adhesive. The epoxy adhesives prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were added to a mold, cured at 100°C for 2h, and then cured at 120°C for 1h, and then cooled to room temperature to obtain casting samples, which were prepared into samples that met the test standards. The elongation at break of the samples was tested with reference to standard GB / T 2567-2008 to determine the toughness of the epoxy adhesive. The test results are shown in the following table:

[0034] As can be seen from the above table, the epoxy adhesives prepared in Examples 1 to 4 of the present invention have excellent bonding performance, high temperature resistance and toughness. Comparative Example 1 adds unmodified brucite fiber, which may agglomerate in the matrix, resulting in poor results in various data; Comparative Example 2 adds hydroxyl-terminated polyisoprene rubber, which can be cross-linked with the matrix, but does not introduce a thick alicyclic structure and a rigid anthracene ring, and has poor high temperature resistance. It is not grafted with modified brucite fiber, so the bonding performance and toughness are also poor. Comparative Example 3 does not add a modified composite additive component, so the test results are poor.

[0035] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. An epoxy adhesive having high temperature resistance functionality, characterized in that: The invention comprises the following raw materials in parts by weight: 80-110 parts of epoxy resin, 5-10 parts of diluent, 1-3 parts of defoamer, 4-10 parts of curing agent, 0.5-3.5 parts of accelerator, 3-6 parts of modified composite additive components and 0.4-2 parts of antioxidant.

2. The epoxy adhesive with high temperature resistance functionality according to claim 1, characterized in that: The epoxy resin is bisphenol A epoxy resin or bisphenol F epoxy resin; the diluent is any one of 2-glycidyl ether, polypropylene glycol diglycidyl ether or o-cresol glycidyl ether; the defoamer is dimethyl silicone oil; the curing agent is any one of 4-4' diaminodiphenyl sulfone, dicyandiamide or 4-4' diaminodiphenylmethane; the accelerator is 2-methylimidazole or 2-ethyl-4-methylimidazole; and the antioxidant is antioxidant 1010 or antioxidant 1098.

3. The epoxy adhesive with high temperature resistance functionality according to claim 1, characterized in that: The preparation method of the modified composite additive component comprises the following steps: Step A: Preparation of modified brucite fiber The brucite fiber is added to N,N-dimethylformamide, and ultrasonically dispersed to form a uniform suspension, maleic rosin and a catalyst are added to the suspension, the temperature is raised to 85-95° C., and the mixture is stirred and reacted for 4-5 hours. After cooling to room temperature, the mixture is filtered, washed, and dried to obtain the modified brucite fiber. Step B, preparation of modified rubber Add the hydroxy-terminated polyisoprene rubber to xylene, stir evenly, add halogenated anthracene and potassium carbonate solution, introduce nitrogen protection and raise the temperature to 70-85°C, react for 3-5 hours, cool and separate the product to obtain modified rubber; Step C: Preparation of modified composite additive components The modified brucite fiber is added into dimethyl sulfoxide, and ultrasonically dispersed to form a uniform suspension. The modified rubber and the composite catalyst are added into the suspension, and after stirring for 6-8 hours, the mixture is centrifuged, washed and dried to obtain a modified composite additive component.

4. The epoxy adhesive with high temperature resistance functionality according to claim 3, characterized in that: In step A, the catalyst is p-toluenesulfonic acid.

5. The epoxy adhesive with high temperature resistance functionality according to claim 3, characterized in that: In step B, the number average molecular weight of the hydroxyl-terminated polyisoprene rubber is 2000.

6. The epoxy adhesive with high temperature resistance functionality according to claim 3, characterized in that: In step B, the halogenated anthracene is 9-chloromethylanthracene or 9-bromomethylanthracene.

7. The epoxy adhesive with high temperature resistance functionality according to claim 3, characterized in that: In step B, the molar ratio of the hydroxyl-terminated polyisoprene rubber to the halogenated anthracene is 1:0.8-1.

8. The epoxy adhesive with high temperature resistance functionality according to claim 3, characterized in that: In step C, the composite catalyst is dicyclohexylcarbodiimide and N-hydroxysuccinimide in a mass ratio of 0.6-1:0.1-0.

3.

9. A process for preparing the epoxy adhesive with high temperature resistance functionality as claimed in claim 1, characterized in that: The following steps are involved: Step 1: adding epoxy resin, diluent, defoamer, modified composite additive component and antioxidant into a high-speed mixer, mixing and stirring for 50-80 minutes to obtain a mixture; Step 2: Add curing agent and accelerator to the mixture, raise the temperature to 60-90°C, stir at a stirring rate of 200-500 r / min for 2-5 hours, and cool to room temperature to obtain the epoxy adhesive.

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