Epoxy resin-based prepreg with low dielectric constant and preparation method thereof

Abstract

The invention discloses a low-dielectric-constant epoxy resin-based prepreg and a preparation method thereof, epoxy resin, a curing agent, an accelerant, a flexibilizer, a filler, color paste and the like are used as basic raw materials, and the epoxy resin adopts high-bromine epoxy resin as a flame retardant; a latent material is adopted as a curing agent and an accelerant; inorganic matters such as aluminum hydroxide, aluminum oxide, glass beads and metal antimony oxide are used as fillers, so that the insulating property of the material is improved, and the dielectric constant of the material is less than 5. The prepreg is prepared by adopting a hot melting method, release paper is coated with an epoxy resin matrix to obtain a resin adhesive film, then a glass fiber fabric is fully infiltrated by the resin matrix by applying certain pressure and temperature, and the preparation process is simple and reliable. The product has good mechanical property and molding effect, and the prepreg can be pressed into the required automobile battery cover at a proper curing temperature by adopting a PCM (Pulse Code Modulation) process.

Description

Technical Field

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

[0002] The dielectric constant is a measure of a material's ability to respond to an electric field, which reflects the mobility of charges in the material and the propagation of the electric field. The lower the dielectric constant, the smaller the capacitance value, which is suitable for high-frequency applications, can reduce the phase delay and distortion of the signal, and the signal transmission speed is also faster. In addition, materials with low dielectric constants have a lower electric field coupling coefficient, which can reduce mutual interference between circuits and improve the system's anti-interference ability, thereby reducing crosstalk interference, which is of great significance for the performance improvement and stable operation of electronic equipment. Therefore, in the fields of electronics, communications, microelectronic devices, etc., the use of materials with low dielectric constants has important application value and broad development prospects.

[0003] The dielectric constants of general-purpose epoxy prepregs on the market are basically between 5 and 6, while composite materials used for battery sealing covers of new energy vehicles often require a dielectric constant less than 5. Therefore, current materials are difficult to meet market demand. Summary of the invention

[0004] In view of the defects of the prior art, the present invention provides a low dielectric constant epoxy resin-based prepreg with fast curing, low dielectric constant, good product flame retardancy, good mechanical properties and molding effect, and a preparation method thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solution: a low dielectric constant epoxy resin-based prepreg, characterized in that it is composed of inevitable impurities and the following raw materials in parts by weight:

[0006] Epoxy resin: 55-85 parts;

[0007] Filler: 5-15 parts;

[0008] Curing agent: 3-12 parts;

[0009] Accelerator: 3-10 parts;

[0010] Toughening agent: 0-15 parts;

[0011] Color paste: 0.5 to 2 parts.

[0012] Preferably, the epoxy resin is a combination of at least two of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, alicyclic epoxy resin, and high-bromine epoxy resin.

[0013] Preferably, the curing agent is a latent curing agent, which is one or a combination of dicyandiamide, acid anhydride, and modified polyamine.

[0014] Preferably, the accelerator is one or a combination of imidazole, tertiary amine, and organic urea.

[0015] Preferably, the filler is one or a combination of aluminum hydroxide, aluminum oxide, glass beads, metal antimony oxides, such as antimony trioxide, antimony pentoxide, glass beads, aluminum oxide, aluminum hydroxide and other inorganic materials.

[0016] Preferably, the toughening agent is core-shell rubber 2672 and / or toughened epoxy resin.

[0017] Preferably, the color paste is made of at least one of carbon black, epoxy resin and wetting and dispersing agent.

[0018] The preparation method of the low dielectric constant epoxy resin-based prepreg is carried out according to the following steps:

[0019] (1) melting each epoxy resin at a temperature of 90-100° C. and stirring the mixture to obtain a mixed solution A;

[0020] (2) adding a color paste and a toughening agent to the mixed solution A obtained in step (1), and stirring the mixture at a temperature of 65-80° C. to obtain a mixed solution B;

[0021] (3) adding filler to the mixed solution B obtained in step (2), stirring uniformly at a temperature of 65-80° C. to obtain a mixed solution C;

[0022] (4) adding a curing agent and an accelerator to the mixed solution C obtained in step (3), stirring the mixture at a temperature of 60-75° C. to obtain a mixed solution D;

[0023] (5) applying glue to the mixed solution D and pre-impregnating it with reinforcing fibers or fabrics to obtain a finished product;

[0024] The dielectric constant of the epoxy resin-based prepreg product obtained is less than 5, and the product can be molded by using the PCM process.

[0025] The epoxy resin uses high-bromine epoxy resin as a flame retardant, and the viscosity of the prepared epoxy resin base at 70° C. is 6000-20000 cps, preferably 9000-18000 cps.

[0026] The present invention uses epoxy resin, curing agent, accelerator, toughening agent, filler and color paste as basic raw materials. The epoxy resin uses high-bromine epoxy resin as a flame retardant; latent materials are used as curing agents and accelerators; inorganic substances such as aluminum hydroxide, aluminum oxide, glass beads, and metal antimony oxides are used as fillers to improve the insulation performance of the material so that the dielectric constant of the material is less than 5. The prepreg is prepared by hot melt method, firstly, the epoxy resin matrix is ​​coated on the release paper to obtain a resin film, and then the resin matrix is ​​fully impregnated with the glass fiber fabric by applying a certain pressure and temperature. The preparation process is simple and reliable. The product has good mechanical properties and molding effect. The PCM process can be used to press the prepreg into the required automotive battery cover at a suitable curing temperature. DETAILED DESCRIPTION

[0027] The present invention will be further described below by means of specific embodiments:

[0028] Example 1

[0029] The prepreg is prepared by a hot melt method, 50 kg of liquid bisphenol A, 10 kg of solid bisphenol A epoxy resin, and 40 kg of high-bromine epoxy resin are placed in a 500 L reactor with a vacuum device, stirred at 95° C. for 4 hours, and mixed solution A is obtained after being stirred evenly; 5 kg of color paste, 8 kg of glass beads, and 8 kg of metal oxide are added to the mixed solution A, and stirred at 80° C. for 5 minutes at a speed of 1500 rpm, and mixed solution B is obtained after being stirred evenly; the mixed solution B is cooled to 50-70° C., and then 10 kg of dicyandiamide curing agent is added, and mixed solution C is obtained after being stirred at 70° C., and then 4 kg of imidazole-type accelerator is added and mixed and stirred evenly to obtain mixed solution D; the viscosity of the mixed solution D is 9000-20000 cps;

[0030] The mixed liquid D is put into the glue coating machine, the glue coating temperature of the equipment is 40-65℃, the glue coating rate is set to 10m / min, the thickness of the glue film is detected by an infrared instrument, and the temperature of the glue film is quickly reduced to room temperature by a cooling plate, thereby obtaining the glue film used for prepreg; then the above glue film is drawn out from the upper and lower glue film rollers of the prepreg machine and mixed with 400g / m 2 The glass fiber cloth forms a sandwich structure, the distance between each roller is fixed, the temperature of the heating roller is 50-75°C, the resin matrix is ​​melted, the fiber impregnation rate is 10m / min, so that the resin matrix can fully infiltrate the glass fiber cloth, and the cooling plate is also used to quickly reduce the temperature of the prepreg to room temperature.

[0031] Example 2

[0032] The prepreg was prepared by hot melt method. 60kg of liquid bisphenol A, 10kg of solid bisphenol A epoxy resin and 30kg of high-bromine epoxy resin were placed in a 500L reactor with a vacuum device, and stirred for 15 minutes after melting at 100°C to obtain a mixed solution A; 5kg of color paste, 5kg of metal oxide and 10kg of core-shell rubber 2672 were added to the mixed solution A, and stirred at 70°C at a speed of 500-1000 rpm for 4 hours to obtain a mixed solution B; the mixed solution B was cooled to 50-70°C, and then 13kg of dicyandiamide curing agent was added, and the mixed solution C was obtained after stirring at 60°C for 10 minutes, and then 3.5kg of imidazole type accelerator was added and mixed and stirred to obtain a mixed solution D; the viscosity of the mixed solution D was 9000-20000cps;

[0033] The mixed liquid D is put into the glue coating machine, the glue coating temperature of the equipment is 40-65℃, the glue coating rate is set to 10m / min, the thickness of the glue film is detected by an infrared instrument, and the temperature of the glue film is quickly reduced to room temperature by a cooling plate, thereby obtaining the glue film used for prepreg; then the above glue film is drawn out from the upper and lower glue film rollers of the prepreg machine and mixed with 400g / m 2 The glass fiber cloth forms a sandwich structure, the distance between each roller is fixed, the temperature of the heating roller is 50-75°C, the resin matrix is ​​melted, the fiber impregnation rate is 10m / min, so that the resin matrix can fully infiltrate the glass fiber cloth, and the cooling plate is also used to quickly reduce the temperature of the prepreg to room temperature.

[0034] Example 3

[0035] The prepreg is prepared by a hot melt method. 35 kg of liquid bisphenol A, 15 kg of solid bisphenol A epoxy resin, 30 kg of high-bromine epoxy resin, and 20 kg of EMX 1401 (EX) core-shell toughened epoxy resin are placed in a 500 L reactor with a vacuum device, melted at 90° C., stirred for 30 minutes, and stirred evenly to obtain a mixed solution A; 5 kg of color paste is added to the mixed solution A, and stirred at 65° C. at a speed of 1500 rpm for 5 minutes, and stirred evenly to obtain a mixed solution B; the mixed solution B is cooled to 70° C., and then 10 kg of dicyandiamide curing agent is added, and stirred at 75° C. for 10 minutes to obtain a mixed solution C, and then 3 kg of imidazole-type accelerator is added and mixed and stirred evenly to obtain a mixed solution D; the viscosity of the mixed solution D is 9000-20000 cps;

[0036] The mixed liquid D is put into the glue coating machine, the glue coating temperature of the equipment is 50-70℃, the glue coating rate is set to 12m / min, the thickness of the glue film is detected by an infrared instrument, and the temperature of the glue film is quickly reduced to room temperature by a cooling plate, thereby obtaining the glue film used for prepreg; then the above glue film is drawn out from the upper and lower glue film rollers of the prepreg machine and mixed with 400g / m 2The glass fiber cloth forms a sandwich structure, the distance between each roller is fixed, the temperature of the heating roller is 50-75°C, the resin matrix is ​​melted, the fiber impregnation rate is 10m / min, so that the resin matrix can fully infiltrate the glass fiber cloth, and the cooling plate is also used to quickly reduce the temperature of the prepreg to room temperature.

[0037] The dielectric constant was tested according to GB / T 1409-2006, with the test conditions of 1MHz, 1V,

[0038] Table 1 Comparison of dielectric constants of products in different implementation cases

[0039] Test items Example 1 Example 2 Example 3 EV101-UL(B) BIGPF400-41%-1270 Material thickness / mm 1.5 1.5 1.5 1.5 1.5 Dielectric constant 4.0 3.5 3.7 5.4 5.6

[0040] It can be seen from the test results in Table 1 above that the dielectric constant of the board pressed from the low dielectric constant epoxy resin-based prepreg prepared by the method of the present invention is between 3.5 and 4.0, which is lower than the dielectric constants of the two prepregs EV101-UL (B) and BIGPF400-41%-1270 on the market, and has better application effect.

[0041] 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 low dielectric constant epoxy resin-based prepreg, characterized in that: It is composed of inevitable impurities and the following raw materials in parts by weight: Epoxy resin: 55-85 parts; Filler: 5-15 parts; Curing agent: 3-12 parts; Accelerator: 3-10 parts; Toughening agent: 0-15 parts; Color paste: 0.5 to 2 parts.

2. The low dielectric constant epoxy resin-based prepreg according to claim 1, characterized in that: The epoxy resin is a combination of at least two of bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, alicyclic epoxy resin, and high-bromine epoxy resin.

3. The low dielectric constant epoxy resin-based prepreg according to claim 1, characterized in that: The curing agent is a latent curing agent, and the curing agent is one or a combination of dicyandiamide, acid anhydride, and modified polyamine.

4. The low dielectric constant epoxy resin-based prepreg according to claim 1, characterized in that: The accelerator is one or a combination of imidazole, tertiary amine, and organic urea.

5. The low dielectric constant epoxy resin-based prepreg according to claim 1, characterized in that: The filler is one or a combination of aluminum hydroxide, aluminum oxide, glass microspheres, and metal antimony oxide.

6. The low dielectric constant epoxy resin-based prepreg according to claim 1, characterized in that: The toughening agent is core-shell rubber 2672 and / or toughened epoxy resin.

7. The low dielectric constant epoxy resin-based prepreg according to claim 1, characterized in that: The color paste is made of at least one of carbon black, epoxy resin and wetting dispersant.

8. A method for preparing the low dielectric constant epoxy resin-based prepreg according to any one of claims 1 to 7, characterized in that: Follow these steps: (1) melting each epoxy resin at a temperature of 90-100° C. and stirring the mixture to obtain a mixed solution A; (2) adding a color paste and a toughening agent to the mixed solution A obtained in step (1), and stirring the mixture at a temperature of 65-80° C. to obtain a mixed solution B; (3) adding filler to the mixed solution B obtained in step (2), stirring uniformly at a temperature of 65-80° C. to obtain a mixed solution C; (4) adding a curing agent and an accelerator to the mixed solution C obtained in step (3), stirring the mixture at a temperature of 60-75° C. to obtain a mixed solution D; (5) applying glue to the mixed solution D and pre-impregnating it with reinforcing fibers or fabrics to obtain a finished product; The dielectric constant of the epoxy resin-based prepreg product obtained is less than 5.

9. The preparation method according to claim 8, characterized in that: The viscosity of the epoxy resin base obtained at 70°C is 6000-20000 cps.