A high-viscosity and high-toughness epoxy resin composite material and preparation method thereof

Abstract

The invention relates to the field of organic resin materials, in particular to a high-viscosity and high-toughness epoxy resin composite material and a preparation method thereof. The epoxy resin component is composed of an epoxy resin component and a curing agent in a mass ratio of 5-10:1; the epoxy resin component is composed of a bisphenol A epoxy resin, a filler and a modifier, and the structural formula of the modifier is as follows: m and n are the same, and m and n are 4, 5 or 6. The epoxy resin composite material prepared by the invention has excellent mechanical properties and has broad application prospects in the fields of high-end equipment maintenance, electronic equipment packaging and protection, and mechanical structure reinforcement and repair.

Description

Technical Field

[0001] The invention relates to the field of organic resin materials, in particular to a high-viscosity and high-toughness epoxy resin composite material and a preparation method thereof. Background Art

[0002] Due to its structural characteristics, epoxy resin will form a three-dimensional cross-linked network structure after curing with a curing agent under certain reaction conditions. This structure determines that epoxy resin has excellent mechanical strength, good corrosion resistance, high thermal stability, and excellent bonding properties. At the same time, epoxy resin also has many advantages such as small shrinkage during the curing reaction, simple processing technology, low raw material cost, and good electrical insulation performance. It is often used as a coating for civil engineering, automobiles, ships, factory equipment, etc., an adhesive for large bodies such as electronic appliances, automobiles, and airplanes, and is used to manufacture molds, laminates, castings, and carbon fiber reinforced composite parts.

[0003] Epoxy resins with different viscosities are suitable for different application fields. Low-viscosity epoxy resins are suitable for processes that require good permeability and strong fluidity, such as injection and impregnation. Medium-viscosity epoxy resins are suitable for composite material preparation and can be used for processes such as coating of fiber-reinforced composite materials. High-viscosity epoxy resins are suitable for processes that require good bonding strength and sealing properties, such as bonding and potting.

[0004] The cross-linked network structure generated after high-viscosity epoxy resin is cured has a large cross-linking density. The rigid benzene ring structure in the main chain of bisphenol A epoxy resin causes the high-viscosity epoxy resin after curing to have strong rigidity but poor toughness. Therefore, it needs to be toughened and modified so that it has high toughness on the basis of excellent mechanical properties. Summary of the invention

[0005] Purpose of the invention: In view of the above technical problems, the present invention proposes a high-viscosity and high-toughness epoxy resin composite material and a preparation method thereof.

[0006] The technical solutions adopted are as follows:

[0007] A high-viscosity and high-toughness epoxy resin composite material, consisting of an epoxy resin component and a curing agent in a mass ratio of 5-10:1;

[0008] The epoxy resin component consists of bisphenol A epoxy resin, filler and modifier;

[0009] The structural formula of the modifier is as follows:

[0010] ;

[0011] m and n are the same, m and n are 4, 5 or 6;

[0012] The filler is epoxy silicon dioxide;

[0013] The curing agent consists of isophorone diamine and triethylene tetramine in a mass ratio of 1-5:1-5.

[0014] Furthermore, the preparation method of the modifier is as follows:

[0015] ;

[0016] S1: Compound A first reacts with thionyl chloride and then undergoes esterification reaction with compound B to generate compound C;

[0017] ;

[0018] S2: Compound C is oxidized by m-chloroperbenzoic acid to obtain the modifier.

[0019] Furthermore, the mass ratio of the bisphenol A epoxy resin, the filler and the modifier is 1:0.01-0.1:0.1-0.2.

[0020] Furthermore, the preparation method of the epoxy silicon dioxide is as follows:

[0021] Add tetraethyl orthosilicate and KH-560 to ethanol and mix well. Add ethanol aqueous solution dropwise in a water bath at 40-60°C. After the addition, react for 5-10 hours. Remove the water bath and age at room temperature for 12-48 hours to obtain a gel. Finally, freeze-dry the obtained gel and grind it.

[0022] Furthermore, the molar ratio of tetraethyl orthosilicate to KH-560 is 1-3:1-3.

[0023] The present invention also provides a method for preparing the above-mentioned high-viscosity and high-toughness epoxy resin composite material:

[0024] The bisphenol A epoxy resin, filler and modifier are pre-mixed to obtain an epoxy resin component, and then the epoxy resin component is mixed with a curing agent and heated to cure.

[0025] Beneficial effects of the present invention:

[0026] The invention provides a high-viscosity and high-toughness epoxy resin composite material. The structure of the added modifier contains both rigid benzene rings and flexible alkyl long chains and cyclohexyl groups with good compatibility with bisphenol A epoxy resin. The four epoxy groups contained can participate in the cross-linking and curing of the bisphenol A epoxy resin, enter the epoxy resin material matrix in the form of chemical bonds, and act as a cross-linking agent to transform the epoxy resin from a linear structure to a three-dimensional structure, becoming a connection point of a spatial network and playing an anchoring role, thereby reducing the distance between the epoxy resin molecular chains and increasing the acting force, which ultimately leads to the improvement of its mechanical strength. Epoxy silicon dioxide can be used as a filler to fill the gaps in the epoxy resin during the curing process. The microcracks and pores generated in the epoxy resin are adsorbed and cross-linked to form physical / chemical cross-linking points, and the toughness and strength of the epoxy resin composite material are improved by crack turning toughening and phase change toughening. Triethylenetetramine has the advantages of high reaction activity and fast curing speed. There is an alicyclic structure in the molecular structure of isophoronediamine, and the product after curing with epoxy resin has better mechanical properties. By combining the two, an epoxy resin composite material with better performance can be obtained. The epoxy resin composite material prepared by the present invention has excellent mechanical properties and has broad application prospects in the fields of high-end equipment maintenance, electronic equipment packaging and protection, and mechanical structure reinforcement and repair. DETAILED DESCRIPTION

[0027] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially. The techniques not mentioned in the present invention are all referenced to the prior art. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0028] Embodiment 1:

[0029] A high-viscosity and high-toughness epoxy resin composite material, consisting of an epoxy resin component and a curing agent in a mass ratio of 8:1;

[0030] The epoxy resin component is composed of a mixture of bisphenol A epoxy resin (Lion Mountain E-51 resin) with a mass ratio of 1:0.05:0.1, a filler and a modifier. The viscosity of the epoxy resin component is tested by standing at a constant temperature of 25°C for 10 minutes using a 16# needle. The reading is read after stabilization, and the viscosity is 86750mpa·s.

[0031] The curing agent is composed of isophorone diamine and triethylene tetramine in a mass ratio of 1:1;

[0032] Wherein, the filler is epoxy silicon dioxide, and the specific preparation method is as follows:

[0033] Add 0.3 mol of tetraethyl orthosilicate and 0.4 mol of KH-560 to 200 ml of ethanol and mix well. Add 25 ml of 50 wt% ethanol aqueous solution dropwise in a 60°C water bath. After the addition is completed, keep the temperature for 8 hours. Remove the water bath and age at room temperature for 24 hours to obtain a gel. Finally, freeze-dry the obtained gel at -50°C and grind it into powder.

[0034] The structural formula of the modifier is as follows:

[0035] ;

[0036] The preparation method of the modifier is as follows:

[0037] ;

[0038] S1: Under nitrogen protection, 36.8g of compound A was added to 100ml of thionyl chloride, stirred and mixed, and then 1ml of DMF was added. The mixture was heated to reflux for reaction for 8h and then returned to room temperature. The excess thionyl chloride was removed by vacuum distillation. The reaction product was dissolved with an appropriate amount of dichloromethane and then dripped into 100ml of n-hexane. The mixture was crystallized at low temperature in a -5°C cold trap for 8h, filtered, and vacuum dried to obtain acyl chloride. 20.2g of acyl chloride and 18g of compound B were added to 200ml of dichloromethane, stirred and mixed in an ice-water mixed bath, and then 5ml of triethylamine was added. After the reaction was kept warm for 2h, the ice-water mixed bath was removed and the reaction was continued for 2h. After the reaction was completed, 200ml of saturated sodium bicarbonate solution was added to the reaction solution, and the dichloromethane phase was separated after sufficient stirring. The phase was dried over anhydrous sodium sulfate and vacuum distilled to obtain compound C;

[0039] ;

[0040] S2: 0.01 mol of compound C was dissolved in 100 ml of dichloromethane, and the mixture was stirred rapidly in an ice-water mixed bath. 0.012 mol of m-chloroperbenzoic acid was added, and the mixture was stirred and reacted for 3 h. The reaction solution was washed with saturated sodium bicarbonate solution and saturated brine in turn, and the separated dichloromethane phase was dried over anhydrous sodium sulfate and then distilled under reduced pressure to obtain the target product. ESI-MS (m / z) (M + ): Theoretical value 757.02, measured value 757.15.

[0041] Embodiment 2:

[0042] A high-viscosity and high-toughness epoxy resin composite material, consisting of an epoxy resin component and a curing agent in a mass ratio of 8:1;

[0043] The epoxy resin component is composed of a mixture of bisphenol A epoxy resin (Shizishan brand E-51 resin), filler and modifier in a mass ratio of 1:0.05:0.1;

[0044] The curing agent is composed of isophorone diamine and triethylene tetramine in a mass ratio of 1:3;

[0045] The preparation method of filler and modifier is the same as that of Example 1.

[0046] Embodiment 3:

[0047] A high-viscosity and high-toughness epoxy resin composite material, consisting of an epoxy resin component and a curing agent in a mass ratio of 8:1;

[0048] The epoxy resin component is composed of a mixture of bisphenol A epoxy resin (Shizishan brand E-51 resin), filler and modifier in a mass ratio of 1:0.05:0.1;

[0049] The curing agent is composed of isophorone diamine and triethylene tetramine in a mass ratio of 1:5;

[0050] The preparation method of filler and modifier is the same as that of Example 1.

[0051] Embodiment 4:

[0052] A high-viscosity and high-toughness epoxy resin composite material, consisting of an epoxy resin component and a curing agent in a mass ratio of 8:1;

[0053] The epoxy resin component is composed of a mixture of bisphenol A epoxy resin (Shizishan brand E-51 resin), filler and modifier in a mass ratio of 1:0.05:0.1;

[0054] The curing agent is composed of isophorone diamine and triethylene tetramine in a mass ratio of 3:1;

[0055] The preparation method of filler and modifier is the same as that of Example 1.

[0056] Embodiment 5:

[0057] A high-viscosity and high-toughness epoxy resin composite material, consisting of an epoxy resin component and a curing agent in a mass ratio of 8:1;

[0058] The epoxy resin component is composed of a mixture of bisphenol A epoxy resin (Shizishan brand E-51 resin), filler and modifier in a mass ratio of 1:0.05:0.1;

[0059] The curing agent is composed of isophorone diamine and triethylene tetramine in a mass ratio of 5:1;

[0060] The preparation method of filler and modifier is the same as that of Example 1.

[0061] Comparative Example 1:

[0062] The method is basically the same as Example 1, except that the epoxy resin component does not contain a modifier.

[0063] Comparative Example 2:

[0064] The method is substantially the same as Example 1, except that the epoxy resin component does not contain fillers.

[0065] Comparative Example 3:

[0066] The method is basically the same as Example 1, except that commercially available nano-silica is used as filler instead of epoxy-silica.

[0067] Comparative Example 4:

[0068] The method is basically the same as Example 1, except that isophorone diamine is used as the curing agent.

[0069] Comparative Example 5:

[0070] The method is basically the same as Example 1, except that triethylenetetramine is used as the curing agent.

[0071] Performance Test:

[0072] The epoxy resin components and curing agents in Examples 1-5 and Comparative Examples 1-5 were mixed and stirred uniformly, poured into a preheated stainless steel mold coated with vacuum silicone grease (for easy demolding), placed in an oven, first stored at 80°C for 12 hours, then heated at a rate of 1°C / min, and successively kept at 150°C, 180°C and 210°C for 2 hours before demolding to obtain a sample, and relevant mechanical properties tests were performed on the sample. The test results are shown in Table 1 below.

[0073] Tensile performance test: standard specimens were prepared according to GB / T 1040.2-2006 1A, and tensile tests were performed using a universal testing machine, loading and destroying the specimens at a speed of 50 mm / min.

[0074] Fracture toughness test: Standard specimens were prepared according to ASTM D5045-2014, and a three-point bending test was carried out on a universal testing machine. The test span was 48 mm, a blade was used to preform the initial crack, and the test rate was 1 mm / min.

[0075] Table 1:

[0076] ;

[0077] It can be seen from Table 1 above that the epoxy resin composite material prepared in the present invention has excellent mechanical properties.

[0078] By comparing the data of Examples 1-5, it can be seen that the mass ratio of isophorone diamine and triethylenetetramine in the curing agent has a certain influence on the mechanical properties of the prepared epoxy resin composite material. When the curing agent is composed of isophorone diamine and triethylenetetramine in a mass ratio of 3:1, the mechanical properties of the epoxy resin composite material are optimal.

[0079] By comparing the data of Example 1 with that of Comparative Example 1, it can be seen that the addition of the modifier can greatly improve the mechanical properties of the epoxy resin composite material.

[0080] By comparing the data of Example 1 with Comparative Examples 2-3, it can be seen that epoxy silica as a filler can greatly improve the mechanical properties of epoxy resin composite materials, and the epoxy groups on its surface can also participate in cross-linking and curing to further improve the mechanical properties of epoxy resin composite materials.

[0081] By comparing the data of Example 1 with Comparative Examples 4-5, it can be seen that the curing agent composed of isophoronediamine and triethylenetetramine has a greater improvement in the mechanical properties of the epoxy resin composite material than using only isophoronediamine or triethylenetetramine as a curing agent.

[0082] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-viscosity and high-toughness epoxy resin composite material, characterized in that: It is composed of an epoxy resin component and a curing agent in a mass ratio of 5-10:1; The epoxy resin component consists of bisphenol A epoxy resin, filler and modifier; The structural formula of the modifier is as follows: ； m and n are the same, m and n are 4, 5 or 6; The filler is epoxy silicon dioxide; The curing agent consists of isophorone diamine and triethylene tetramine in a mass ratio of 1-5:1-5.

2. The high-viscosity and high-toughness epoxy resin composite material according to claim 1, characterized in that: The preparation method of the modifier is as follows: ； S1: Compound A first reacts with thionyl chloride and then undergoes esterification reaction with compound B to generate compound C; ； S2: Compound C is oxidized by m-chloroperbenzoic acid to obtain the modifier.

3. The high-viscosity and high-toughness epoxy resin composite material according to claim 1, characterized in that: The mass ratio of the bisphenol A epoxy resin, the filler and the modifier is 1:0.01-0.1:0.1-0.

2.

4. The high-viscosity and high-toughness epoxy resin composite material according to claim 1, characterized in that: The preparation method of the epoxy silicon dioxide is as follows: Add tetraethyl orthosilicate and KH-560 to ethanol and mix well. Add ethanol aqueous solution dropwise in a water bath at 40-60°C. After the addition, react for 5-10 hours. Remove the water bath and age at room temperature for 12-48 hours to obtain a gel. Finally, freeze-dry the obtained gel and grind it.

5. The high-viscosity and high-toughness epoxy resin composite material according to claim 4, characterized in that: The molar ratio of tetraethyl orthosilicate to KH-560 is 1-3:1-3.

6. A method for preparing a high-viscosity and high-toughness epoxy resin composite material as claimed in any one of claims 1 to 5, characterized in that: The bisphenol A epoxy resin, filler and modifier are pre-mixed to obtain an epoxy resin component, and then the epoxy resin component is mixed with a curing agent and heated to cure.

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