High-adhesion epoxy prepreg and preparation method thereof

Abstract

Solid epoxy resin, semi-solid epoxy resin and liquid epoxy resin are adopted as matrix resin, and the high-adhesion epoxy prepreg is prepared by adjusting the proportion of epoxy resin in various forms. And the epoxy prepreg with the sandwich structure is prepared through the steps of stirring, coating to form a film, carrying out sandwich molding with glass fiber cloth and the like. According to the present invention, with the epoxy resin, the bonding performance of the epoxy prepreg can be significantly improved, and the high mechanical strength can be maintained so as to completely provide the bonding performance of the epoxy resin after the epoxy prepreg is compounded with the steel plate, such that the interface performance of the prepreg and the metal can be improved, and the structure bearing performance of the prepreg in the whole life cycle in the power battery can be met. And the preparation method is simple, the production process is safe, the operation is easy, the production efficiency is high, the production cost can be reduced, the market application value is very high, and the application prospect is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical materials, and in particular to a high-adhesion epoxy prepreg material applicable to industries such as new energy vehicles and a preparation method thereof. Background Art

[0002] Fiber reinforced composite materials are mainly composed of high-performance resins and fiber reinforcement materials. Epoxy resins are widely used in composite materials and other fields due to their good electrical properties, chemical stability, and excellent mechanical properties and bonding properties. Epoxy prepregs have always received widespread attention due to their excellent performance. In the research and development of lightweight automobiles, there is inevitably the problem of bonding between prepregs and dissimilar materials such as metals. The reliability of the bonding between prepregs and metals is the basis for structural strength calculations and is related to the safety evaluation of the entire life cycle of power batteries. Once the composite material and metal are peeled off, its bearing capacity will be greatly reduced. However, after the traditional conventional epoxy prepreg is compounded with metal, its roller peeling strength is low and cannot meet the technical requirements of the entire life cycle of power batteries. Therefore, it is necessary to study high-bonding epoxy prepregs so that they can give full play to the bonding properties of epoxy resins after being compounded with steel plates, and improve the interface properties between prepregs and metals to meet their structural bearing performance in the entire life cycle of power batteries. Summary of the invention

[0003] In view of the defects in the prior art, the present invention provides a high-adhesion epoxy prepreg with good bonding performance, high mechanical strength and good material toughness and a preparation method thereof.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: a high-adhesion epoxy prepreg, the raw materials include component a and component b, component a is glass fiber cloth, component b is composed of inevitable impurities and the following raw materials in parts by weight:

[0005] Solid epoxy resin 20-25%

[0006] Semi-solid epoxy resin 20-25%

[0007] Liquid epoxy resin 0-10%

[0008]

[0009] The total weight percentage of component a and component b is 100%, and component a accounts for 40% of the total weight.

[0010] Preferably, the curing agent is dicyandiamide curing agent, and the purity of the curing agent is greater than 96%.

[0011] Preferably, the accelerator is a substituted urea accelerator with a purity greater than 98%.

[0012] Preferably, the flame retardant is decabromodiphenylethane and antimony trioxide, with weights of 4.5% and 2.5% respectively, and the particle sizes of decabromodiphenylethane and antimony trioxide are 100-300 meshes.

[0013] Preferably, the glass fiber cloth is an alkali-free glass fiber cloth with a gram weight of 400-600g / m 2 .

[0014] The preparation method of the aforementioned high-adhesion epoxy prepreg is carried out according to the following steps:

[0015] 1) adding solid epoxy resin, semi-solid liquid epoxy resin and liquid epoxy resin, preheating in an oven at 120° C. for at least 6 hours, and stirring while hot to obtain a mixture;

[0016] 2) adding color paste, flame retardant, curing agent and accelerator to the mixture obtained in step 1) in sequence, and continuing to stir evenly to obtain epoxy resin paste;

[0017] 3) Preparation of epoxy resin film: pour the prepared epoxy resin paste onto the preheated glue coating roller, and evenly apply the epoxy resin paste onto the release paper by a rotating iron roller to form a preliminary epoxy resin film. The preliminary epoxy resin film is cooled by a cooling plate and then covered with a layer of PE isolation film, and then wound by a winder to obtain a finished epoxy resin film;

[0018] 4) Preparation of prepreg: Divide the finished epoxy resin film into two parts, sandwich the glass fiber cloth between the upper and lower parts of the epoxy resin film, preheat and extrude it through a heating plate and a heated iron roller, so that the epoxy resin fully impregnates the glass fiber to form a sandwich structure epoxy prepreg.

[0019] Wherein, the stirring speed of step 1) is 1000-1500 rpm, and the stirring time is 3-5 min, for example, 3 min, 4 min or 5 min; the stirring time of step 2) is 3-5 min, and the stirring speed is 1000-1500 rpm, for example, 1000 rpm, 1200 rpm or 1500 rpm.

[0020] Among them, in step 1), for solid epoxy resin, semi-solid liquid epoxy resin and liquid epoxy resin, the liquid material and semi-solid material are first added, and then the solid material is added.

[0021] Wherein, the gap of the iron rollers in step 3) is 0.15-0.30 mm, for example, it can be 0.15 mm, 0.20 mm, 0.25 mm or 0.30 mm; the temperature is 65-80°C, for example, it can be 65°C, 70°C, 75 or 80°C.

[0022] Among them, the gap of the iron roller in step 4) is 0.10-0.25mm, for example, it can be 0.10mm, 0.15mm, 0.20mm or 0.25mm; the temperature of the iron roller and the heating plate in step (4) is 65-80℃, for example, it can be 65℃, 70℃, 75 or 80℃.

[0023] The present invention uses solid epoxy resin, semi-solid epoxy resin and liquid epoxy resin as matrix resin, and by adjusting the ratio of epoxy resin in various forms, not only can the bonding performance of epoxy prepreg be significantly improved, but also high mechanical strength can be maintained, so that the bonding performance of epoxy resin can be fully exerted after being compounded with steel plate, the interface performance between prepreg and metal can be improved, and the structural bearing performance of the prepreg in the whole life cycle of the power battery can be met. In addition, the preparation method of the present invention is simple, the production process is safe, easy to operate, and the production efficiency is high, which can reduce the production cost, and has very high market application value and broad application prospects. DETAILED DESCRIPTION

[0024] The present invention is described clearly and completely below through specific embodiments:

[0025] Comparative Example 1

[0026] The resin paste (component b) formula is as follows:

[0027] Components ％ Solid epoxy resin 14.0 Semi-solid epoxy resin 12.0 Liquid epoxy resin 20.0 Color paste 1.5 Flame retardant 1 4.5 Flame retardant 2 2.5 Curing agent 4.5 Accelerator 1.0 450g fiberglass cloth 40

[0028] The specific preparation steps are as follows:

[0029] 1) Preparation of epoxy resin paste: Add liquid epoxy resin, semi-solid epoxy resin and solid epoxy resin and preheat in an oven at 120°C until the epoxy resin melts, then stir at 1500 rpm for 5 minutes to obtain a uniform mixture;

[0030] 2) To the mixture of step 1), color paste, flame retardant and curing agent are added in sequence while stirring at 500 rpm, and stirring is continued at 1500 rpm to obtain a mixture, the material temperature is reduced to below 65° C., and then an accelerator is added; stirring is continued at 1500 rpm to obtain a mixture, and the temperature is controlled not to exceed 70° C.

[0031] 3) Preparation of epoxy resin film: After the glue coating roller is preheated to 70°C, the gap between the glue coating rollers is set to 0.20 mm, and the prepared epoxy resin paste is poured onto the preheated glue coating roller. The epoxy resin paste is evenly coated on the release paper by a rotating iron roller. The epoxy resin film is cooled by a cooling plate and then covered with a layer of PE isolation film, and then wound by a winder to obtain the epoxy resin film.

[0032] 4) Preparation of prepreg: The epoxy resin film is divided into two parts, the glass fiber cloth is sandwiched in the middle, and is preheated and extruded by a heating plate and a heated iron roller. The temperature of the heating plate and the iron roller is set to 75°C, and the gap between the iron rollers is 0.20mm, so that the epoxy resin fully infiltrates the glass fiber to form an epoxy prepreg with a sandwich structure similar to a "sandwich". The prepreg is rolled up and set aside.

[0033] Example 1

[0034] The resin paste (component b) formula is as follows:

[0035] Components ％ Solid epoxy resin 23.5 Semi-solid epoxy resin 18.5 Liquid epoxy resin 4.0 Color paste 1.5 Flame retardant 1 4.5 Flame retardant 2 2.5 Curing agent 4.5 Accelerator 1.0 450g fiberglass cloth 40

[0036] Example 2

[0037] The resin paste (component b) formula is as follows:

[0038] Components ％ Solid epoxy resin 22.5 Semi-solid epoxy resin 19.5 Liquid epoxy resin 4.0 Color paste 1.5 Flame retardant 1 4.5 Flame retardant 2 2.5 Curing agent 4.5 Accelerator 1.0 450g fiberglass cloth 40

[0039] Example 3

[0040] The resin paste (component b) formula is as follows:

[0041] Components ％ Solid epoxy resin 21.5 Semi-solid epoxy resin 20.5 Liquid epoxy resin 4.0 Color paste 1.5 Flame retardant 1 4.5 Flame retardant 2 2.5 Curing agent 4.5 Accelerator 1.0 450g fiberglass cloth 40

[0042] Example 4

[0043] The resin paste (component b) formula is as follows:

[0044] Components ％ Solid epoxy resin 20.5 Semi-solid epoxy resin 18.5 Liquid epoxy resin 7.0 Color paste 1.5 Flame retardant 1 4.5 Flame retardant 2 2.5 Curing agent 4.5 Accelerator 1.0 450g fiberglass cloth 40

[0045] Example 5

[0046] The resin paste (component b) formula is as follows:

[0047] Components ％ Solid epoxy resin 23.5 Semi-solid epoxy resin 15.5 Liquid epoxy resin 7.0 Color paste 1.5 Flame retardant 1 4.5 Flame retardant 2 2.5 Curing agent 4.5 Accelerator 1.0 450g fiberglass cloth 40

[0048] Example 6

[0049] The resin paste formula is as follows:

[0050] Components ％ Solid epoxy resin 23.5 Semi-solid epoxy resin 21.5 Liquid epoxy resin 1.0 Color paste 1.5 Flame retardant 1 4.5 Flame retardant 2 2.5 Curing agent 4.5 Accelerator 1.0 450g fiberglass cloth 40

[0051] The prepregs prepared in the above Examples 1-6 were compounded with electrophoretic steel plates and then subjected to performance tests. The specific test results are shown in Table 1 below:

[0052] Table 1: High adhesion prepreg performance test results

[0053]

[0054] The preparation process of Examples 1 to 6 is basically the same as that of Comparative Example 1, except that the process parameters are adjusted within the numerical range specified in the present invention, such as slight changes in related parameters such as stirring time, stirring speed, iron roller temperature, and iron roller gap.

[0055] It can be seen from the test results in Table 1 above that, compared with the traditional solution (Comparative Example 1), the present invention uses solid epoxy resin, semi-solid epoxy resin and liquid epoxy resin as the matrix resin, and adjusts the ratio of various forms of epoxy resin to give full play to the bonding performance of epoxy resin after compounding with the steel plate. In terms of the comprehensive prepreg preparation process and mechanical properties, increasing the ratio of solid epoxy resin and semi-solid epoxy resin and reducing the use of liquid epoxy resin can effectively improve the roller peeling strength.

[0056] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not limit the scope of implementation of the present invention. That is, all equivalent changes and modifications made within the scope of this application should still fall within the scope of the present invention.

Claims

1. A high-adhesion epoxy prepreg, characterized in that: The raw materials include component A and component B. Component A is glass fiber cloth, and component B is composed of inevitable impurities and the following raw materials in parts by weight: The total weight percentage of component a and component b is 100%, and component a accounts for 40% of the total weight.

2. The high-adhesion epoxy prepreg according to claim 1, characterized in that: The curing agent is dicyandiamide curing agent, and the purity of the curing agent is greater than 96%.

3. The high adhesion epoxy prepreg according to claim 1, characterized in that: The accelerator is a substituted urea accelerator, and the purity of the accelerator is greater than 98%.

4. The high-adhesion epoxy prepreg according to claim 1, characterized in that: The flame retardant uses decabromodiphenylethane and antimony trioxide, with weights of 4.5% and 2.5% respectively. The particle sizes of decabromodiphenylethane and antimony trioxide are 100-300 meshes.

5. The high adhesion epoxy prepreg according to claim 1, characterized in that: The glass fiber cloth is an alkali-free glass fiber cloth with a gram weight of 400-600g / m 2 .

6. A method for preparing the high-adhesion epoxy prepreg according to any one of claims 1 to 5, characterized in that: Follow these steps: 1) adding solid epoxy resin, semi-solid liquid epoxy resin and liquid epoxy resin, preheating in an oven at 120° C. for at least 6 hours, and stirring while hot to obtain a mixture; 2) adding color paste, flame retardant, curing agent and accelerator to the mixture obtained in step 1) in sequence, and continuing to stir evenly to obtain epoxy resin paste; 3) Preparation of epoxy resin film: pour the prepared epoxy resin paste onto the preheated glue coating roller, and evenly apply the epoxy resin paste onto the release paper by a rotating iron roller to form a preliminary epoxy resin film. The preliminary epoxy resin film is cooled by a cooling plate and then covered with a layer of PE isolation film, and then wound by a winder to obtain a finished epoxy resin film; 4) Preparation of prepreg: Divide the finished epoxy resin film into two parts, sandwich the glass fiber cloth between the upper and lower parts of the epoxy resin film, preheat and extrude it through a heating plate and a heated iron roller, so that the epoxy resin fully impregnates the glass fiber to form a sandwich structure epoxy prepreg.

7. The preparation method according to claim 6, characterized in that: The stirring speed of step 1) is 1000-1500 rpm, and the stirring time is 3-5 min; the stirring time of step 2) is 3-5 min, and the stirring speed is 1000-1500 rpm.

8. The preparation method according to claim 6, characterized in that: Step 1) For solid epoxy resin, semi-solid liquid epoxy resin and liquid epoxy resin, first add liquid material and semi-solid material, and then add solid material.

9. The preparation method according to claim 6, characterized in that: The gap between the iron rollers in step 3) is 0.15-0.30 mm and the temperature is 65-80°C.

10. The preparation method according to claim 6, characterized in that: The gap between the iron rollers in step (4) is 0.10-0.25 mm, and the temperature of the iron rollers and the heating plate in step (4) is 65-80°C.

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