Polyperfluorinated ethylene propylene modified polytetrafluoroethylene resin composition, resin glue solution, prepreg and copper-clad plate thereof

Abstract

The invention belongs to the technical field of composite materials, and particularly relates to a fluorinated ethylene propylene modified polytetrafluoroethylene resin composition, a resin glue solution, a prepreg and a copper-clad plate of the prepreg. Comprising the following components: 40 to 60 parts of modified polytetrafluoroethylene powder, 20 to 40 parts of benzoxazine, 20 to 40 parts of bismaleimide resin, 0.2 to 1 part of a curing accelerator, 10 to 20 parts of a flame retardant and 40 to 60 parts of silica powder. The copper-clad plate prepared by the invention has the characteristics of ultralow dielectric loss and dielectric constant, high copper foil peel strength, low expansion coefficient and excellent heat resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a polytetrafluoroethylene resin composition modified with polytetrafluoroethylene (PTFE), a resin adhesive, a prepreg and a copper-clad plate thereof. Background Art

[0002] With the rapid development of the electronics industry, the requirements for the performance of copper clad laminates are getting higher and higher, especially for the three major portable electronic products, satellite transmission and communication electronic products, which are developing in the direction of miniaturization, high frequency and high speed. Especially in the field of high-frequency and high-speed mobile communications, with the development of 5G signal transmission, the signal transmission speed must be faster and faster, and the signal frequency must be higher and higher. Therefore, the printed circuit board material used as the signal transmission carrier must have a lower dielectric constant, and the dielectric loss factor of the material must be small enough. Traditional FR-4 copper clad laminates use epoxy resin as the matrix resin, and its dielectric properties can no longer meet the requirements. There is an urgent need to develop a matrix resin composition with better dielectric properties.

[0003] Polymer-based dielectric composites, with their advantages of low specific gravity, corrosion resistance, and ease of processing and molding, are currently ideal materials for thermal management, particularly in the electrical and electronics fields. To keep pace with advances in microelectronics integration and assembly technology, electronic components are increasingly miniaturized, refined, and multifunctional, leading to a dramatic increase in power output requirements. This inevitably leads to significant heat generation in electronic devices over extended periods, which rapidly accumulates within the device and increases operating temperatures. This leads to problems such as inability to dissipate heat quickly, reducing the lifespan and reliability of the device. To improve the high-temperature reliability of electronic devices and ensure long-term, efficient operation, it is necessary to develop new composite materials with low dielectric loss and high thermal conductivity. Such materials can dissipate heat quickly, preventing excessive internal operating temperatures and maintaining normal operating efficiency even under short-term high temperatures. Dielectric materials are materials that store electrostatic energy. Compared to ceramics, polymer dielectrics offer advantages such as high breakdown strength, high stability, scalability, light weight, and the ability to form complex structures. Therefore, they are ideal for many power electronics, power supply regulation, and pulsed power applications, and are widely used in precision instruments, new energy vehicles, aerospace, and other fields. However, most polymers are thermal insulators, with thermal conductivities typically ranging from 0.1 to 0.5 W / (m·K). Polymer dielectrics are limited by relatively low operating temperatures and cannot meet today's power needs. The dielectric properties of thermally conductive polymers have yet to be fully explored, and existing thermally conductive polymer-based materials are unable to meet the requirements for high performance and high thermal and dielectric properties under extreme conditions. To meet the development needs of manufacturing and technological fields such as electric vehicles, aerospace power electronics, natural gas exploration, and precision electrical and electronics, it is imperative to develop polymer-based composites with excellent comprehensive properties, including low dielectric loss, high thermal conductivity, and low cost. Summary of the Invention

[0004] In view of the deficiencies in the above-mentioned prior art, the present invention provides a polytetrafluoroethylene (PTFE)-modified polytetrafluoroethylene (FEP) resin composition, a resin adhesive, a prepreg and a copper-clad laminate thereof. The prepared copper-clad laminate has the characteristics of ultra-low dielectric loss and dielectric constant, high copper foil peel strength, low expansion coefficient and excellent heat resistance.

[0005] The specific technical solutions are as follows:

[0006] The first object of the present invention is to provide a polytetrafluoroethylene resin composition modified with fluoroethylene propylene, comprising the following components in parts by weight:

[0007]

[0008] Furthermore, the preparation method of the modified polytetrafluoroethylene powder comprises the following steps:

[0009] Weigh polytetrafluoroethylene concentrated water dispersion emulsion and polyperfluoroethylene propylene concentrated dispersion in a weight ratio of 1:2 and place them in a beaker, add an appropriate amount of water and stir evenly at a speed of 450-500r / min, add an appropriate amount of acetone for precipitation, filter the coagulant with gauze, air-dry, and then dry in a vacuum oven at 100-110℃ for 20-24 hours. The presence of polyperfluoroethylene propylene makes the dried powder light yellow. Then extract with acetone 7-10 times to eliminate the presence of polyperfluoroethylene propylene in the powder, thereby obtaining modified polytetrafluoroethylene powder.

[0010] Furthermore, the benzoxazine is any one of phenol-type benzoxazine resin, bisphenol A-type benzoxazine resin, bisphenol F-type benzoxazine resin, bisphenol S-type benzoxazine resin, novolac-type benzoxazine resin, and diamine-type benzoxazine resin.

[0011] Furthermore, the curing accelerator is one or more of boron trifluoride ethylamine, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, triphenylphosphine, tributylphosphine, and triethylphosphine.

[0012] Furthermore, the flame retardant is one or more of tetrabromobisphenol A, decabromodiphenyl ether, decabromodiphenyl ethane, and bromotriazine.

[0013] The second object of the present invention is to provide a resin glue obtained by dissolving or dispersing the above-mentioned polytetrafluoroethylene resin composition modified with polytetrafluoroethylene in an organic solvent.

[0014] Furthermore, the organic solvent is 60-80 parts by weight, and the organic solvent is one or more of toluene, xylene, acetone, and butanone.

[0015] Furthermore, the preparation method of the resin glue comprises the following steps: dissolving the solid first, dissolving the liquid second, and finally adding the filler in the above-mentioned polytetrafluoroethylene resin composition to obtain the polytetrafluoroethylene resin glue.

[0016] The third object of the present invention is to provide a prepreg prepared using the above resin glue.

[0017] Furthermore, the preparation method of the prepreg comprises the following steps: pouring the resin glue into a clean flat plate, dipping the alkali-free glass cloth in the resin glue for 30-50 seconds, taking it out, and baking it in an oven at 160-180° C. for 3-5 minutes to obtain the prepreg.

[0018] Furthermore, the preparation method of the alkali-free glass cloth includes the following steps: heating the glass cloth at 400-500°C for 20-30 minutes, removing the surface paraffin, impregnating the heat-treated glass cloth with a silane coupling agent surface modification liquid for 5-10 minutes, naturally air-drying it, and baking it at 110-120°C for 30-40 minutes to obtain the alkali-free glass cloth.

[0019] Furthermore, the silane coupling agent is KH-6032 silane coupling agent and / or tridecafluorooctyltriethoxysilane.

[0020] The fourth object of the present invention is to provide a copper clad laminate prepared using the above-mentioned prepreg.

[0021] Furthermore, the method for preparing the copper clad laminate comprises the following steps: stacking 4-8 prepregs, then covering both sides of the stacked prepregs with a copper foil, and hot pressing at 180-200°C and 2-5 MPa for 90-150 minutes to produce the copper clad laminate.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] Fluorinated ethylene propylene (FEP) is a copolymer of tetrafluoroethylene and hexafluoropropylene, abbreviated as F46. Its molecular weight is slightly lower than that of PTFE, and the resin's mechanical properties, chemical stability, water absorption, and electrical properties are comparable to those of PTFE. Due to the pendant groups attached to the CC main chain of FEP, its melting temperature is low, at 265±10°C. In the molten state, its viscosity is much lower than that of PTFE, resulting in excellent flow properties, strong fiber penetration, and easier molding and processing than PTFE. It also has low surface tension and strong adhesion to copper foil. Therefore, modifying PTFE with FEP is a method for preparing high-frequency, high-performance copper-clad laminates. The addition of FEP not only improves the product's flexural strength, peel strength, and heat resistance, but also reduces the dielectric loss factor and low expansion coefficient. As a result, the resulting copper-clad laminates exhibit ultra-low dielectric loss and dielectric constant, high copper foil peel strength, a low expansion coefficient, and excellent heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The DSC curves of polytetrafluoroethylene, polytetrafluoroethylene (FEP), and a mixture of the two in the present invention are shown in FIG. 1 ; wherein a) is the DSC curve of polytetrafluoroethylene powder, b) is the DSC curve of modified polytetrafluoroethylene powder prepared in Example 1, and c) is the DSC curve of polytetrafluoroethylene powder.

[0025] Figure 2 This is a scanning electron microscope photograph of the impact cross-section of the modified polytetrafluoroethylene powder material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. The parts described in the specific implementation manner are parts by weight.

[0027] Example 1

[0028] 1. Preparation of modified polytetrafluoroethylene powder

[0029] Weigh 50g of polytetrafluoroethylene concentrated water dispersion and 100g of polyperfluoroethylene propylene concentrated dispersion into a beaker, add an appropriate amount of water and stir evenly at a speed of 450r / min. After adding 100g of acetone for precipitation, filter the coagulant with gauze, air-dry it, and then dry it in a vacuum oven at 100°C for 20 hours. The presence of polyperfluoroethylene propylene makes the dried powder light yellow. Then extract it with acetone 7 times to eliminate the presence of polyperfluoroethylene propylene in the powder, thereby obtaining modified polytetrafluoroethylene powder.

[0030] 2. Preparation of polytetrafluoroethylene resin modified with polytetrafluoroethylene

[0031]

[0032] The above substances are prepared in the order of dissolving the solid first, dissolving the liquid second, and finally adding the filler to obtain the polytetrafluoroethylene resin glue modified by polyperfluoroethylene propylene.

[0033] 3. Preparation of alkali-free glass cloth

[0034] The glass cloth was heated at 400° C. for 30 minutes to remove the surface paraffin, and the heat-treated glass cloth was immersed in a silane coupling agent surface modification liquid for 5 minutes. After natural air drying, the glass cloth was baked at 110° C. for 40 minutes to obtain the alkali-free glass cloth.

[0035] Wherein, the silane coupling agent is KH-6032 silane coupling agent.

[0036] 4. Preparation of prepreg

[0037] Pour the resin glue in step 2 into a clean flat plate, immerse the alkali-free glass cloth in step 3 in the resin glue for 30 seconds, take it out, and bake it in an oven at 160° C. for 3 minutes to obtain a prepreg.

[0038] 5. Preparation of copper clad laminate

[0039] Four prepregs prepared in step 4 were stacked together, and then a copper foil was covered on each side of the stacked prepregs. The copper clad laminate was obtained by hot pressing at 180° C. and 2 MPa for 150 minutes.

[0040] Example 2

[0041] 1. Preparation of modified polytetrafluoroethylene powder

[0042] Weigh 50g of polytetrafluoroethylene concentrated water dispersion and 100g of polyperfluoroethylene propylene concentrated dispersion into a beaker, add an appropriate amount of water and stir evenly at a speed of 500r / min. After adding 100g of acetone for precipitation, filter the coagulant with gauze, air-dry it, and then dry it in a vacuum oven at 110°C for 24 hours. The presence of polyperfluoroethylene propylene makes the dried powder light yellow. Then extract it with acetone 10 times to eliminate the presence of polyperfluoroethylene propylene in the powder, thereby obtaining modified polytetrafluoroethylene powder.

[0043] 2. Preparation of polytetrafluoroethylene resin modified with polytetrafluoroethylene

[0044]

[0045] The above substances are prepared in the order of dissolving the solid first, dissolving the liquid second, and finally adding the filler to obtain the polytetrafluoroethylene resin glue modified by polyperfluoroethylene propylene.

[0046] 3. Preparation of alkali-free glass cloth

[0047] The glass cloth was heated at 500° C. for 20 minutes to remove the surface paraffin, and the heat-treated glass cloth was immersed in a silane coupling agent surface modification liquid for 10 minutes. After natural air drying, the glass cloth was baked at 120° C. for 30 minutes to obtain the alkali-free glass cloth.

[0048] Wherein, the silane coupling agent is KH-6032 silane coupling agent.

[0049] 4. Preparation of prepreg

[0050] Pour the resin glue in step 2 into a clean flat plate, immerse the alkali-free glass cloth in step 3 in the resin glue for 50 seconds, take it out, and bake it in an oven at 180° C. for 4 minutes to obtain a prepreg.

[0051] 5. Preparation of copper clad laminate

[0052] Six prepregs prepared in step 4 were stacked together, and then a copper foil was covered on each side of the stacked prepregs. The copper clad laminate was obtained by hot pressing at 200° C. and 5 MPa for 120 minutes.

[0053] Example 3

[0054] 1. Preparation of modified polytetrafluoroethylene powder

[0055] Weigh 50g of polytetrafluoroethylene concentrated water dispersion and 100g of polyperfluoroethylene propylene concentrated dispersion into a beaker, add an appropriate amount of water and stir evenly at a speed of 480r / min. After adding 100g of acetone for precipitation, filter the coagulant with gauze, air-dry it, and then dry it in a vacuum oven at 105°C for 22 hours. The presence of polyperfluoroethylene propylene makes the dried powder light yellow. Then extract it with acetone 8 times to eliminate the presence of polyperfluoroethylene propylene in the powder, thereby obtaining modified polytetrafluoroethylene powder.

[0056] 2. Preparation of polytetrafluoroethylene resin modified with polytetrafluoroethylene

[0057]

[0058]

[0059] The above substances are prepared in the order of dissolving the solid first, dissolving the liquid second, and finally adding the filler to obtain the polytetrafluoroethylene resin glue modified by polyperfluoroethylene propylene.

[0060] 3. Preparation of alkali-free glass cloth

[0061] The glass cloth was heated at 450° C. for 25 minutes to remove the surface paraffin. The heat-treated glass cloth was immersed in a silane coupling agent surface modification liquid for 7.5 minutes, naturally air-dried, and then baked at 115° C. for 35 minutes to obtain the alkali-free glass cloth.

[0062] Wherein, the silane coupling agent is KH-6032 silane coupling agent.

[0063] 4. Preparation of prepreg

[0064] Pour the resin glue in step 2 into a clean flat plate, immerse the alkali-free glass cloth in step 3 in the resin glue for 40 seconds, take it out, and bake it in an oven at 170° C. for 5 minutes to obtain a prepreg.

[0065] 5. Preparation of copper clad laminate

[0066] Eight prepregs prepared in step 4 were stacked together, and then a copper foil was covered on each side of the stacked prepregs. The copper clad laminate was obtained by hot pressing at 190° C. and 3.5 MPa for 90 minutes.

[0067] Comparative Example 1

[0068] The difference between Comparative Example 1 and Example 1 is that modified polytetrafluoroethylene powder is not used, but polytetrafluoroethylene concentrated water dispersion emulsion is used, specifically as follows:

[0069] 1. Preparation of modified polytetrafluoroethylene resin glue

[0070]

[0071] The above substances are prepared in the order of dissolving the solid first, dissolving the liquid second, and finally adding the filler to obtain the modified polytetrafluoroethylene resin glue.

[0072] 2. Preparation of alkali-free glass cloth

[0073] The glass cloth was heated at 400° C. for 30 minutes to remove the surface paraffin, and the heat-treated glass cloth was immersed in a silane coupling agent surface modification liquid for 5 minutes. After natural air drying, the glass cloth was baked at 110° C. for 40 minutes to obtain the alkali-free glass cloth.

[0074] Wherein, the silane coupling agent is KH-6032 silane coupling agent.

[0075] 3. Preparation of prepreg

[0076] Pour the resin glue in step 1 into a clean flat plate, immerse the alkali-free glass cloth in step 2 in the resin glue for 30 seconds, take it out, and bake it in an oven at 160° C. for 3 minutes to obtain a prepreg.

[0077] 4. Preparation of copper clad laminate

[0078] Four prepregs prepared in step 3 were stacked together, and then a copper foil was covered on each side of the stacked prepregs. The copper clad laminate was obtained by hot pressing at 180° C. and 2 MPa for 150 minutes.

[0079] Comparative Example 2

[0080] The difference between Comparative Example 2 and Example 1 is that instead of using modified polytetrafluoroethylene powder, a concentrated water-dispersed polytetrafluoroethylene emulsion is used, and instead of using alkali-free glass cloth, ordinary untreated glass cloth is used, as follows:

[0081] 1. Preparation of modified polytetrafluoroethylene resin glue

[0082]

[0083] The above substances are prepared in the order of dissolving the solid first, dissolving the liquid second, and finally adding the filler to obtain the modified polytetrafluoroethylene resin glue.

[0084] 2. Preparation of prepreg

[0085] The resin glue in step 1 was poured into a clean flat plate, and the untreated glass cloth was immersed in the resin glue for 30 seconds. The untreated glass cloth was taken out and baked in an oven at 160° C. for 3 minutes to obtain a prepreg.

[0086] 3. Preparation of copper clad laminate

[0087] Four prepregs prepared in step 2 were stacked together, and then a copper foil was covered on each side of the stacked prepregs. The copper clad laminate was obtained by hot pressing at 180° C. and 2 MPa for 150 minutes.

[0088] Comparative Example 3

[0089] The difference between Comparative Example 3 and Example 1 is that, instead of using alkali-free glass cloth, ordinary untreated glass cloth is used, as follows:

[0090] 1. Preparation of modified polytetrafluoroethylene powder

[0091] Weigh 50g of polytetrafluoroethylene concentrated water dispersion and 100g of polyperfluoroethylene propylene concentrated dispersion into a beaker, add an appropriate amount of water and stir evenly at a speed of 450r / min. After adding 100g of acetone for precipitation, filter the coagulant with gauze, air-dry it, and then dry it in a vacuum oven at 100°C for 20 hours. The presence of polyperfluoroethylene propylene makes the dried powder light yellow. Then extract it with acetone 7 times to eliminate the presence of polyperfluoroethylene propylene in the powder, thereby obtaining modified polytetrafluoroethylene powder.

[0092] 2. Preparation of polytetrafluoroethylene resin modified with polytetrafluoroethylene

[0093]

[0094] The above substances are prepared in the order of dissolving the solid first, dissolving the liquid second, and finally adding the filler to obtain the polytetrafluoroethylene resin glue modified by polyperfluoroethylene propylene.

[0095] 3. Preparation of prepreg

[0096] The resin glue in step 2 was poured into a clean flat plate, and the untreated glass cloth was immersed in the resin glue for 30 seconds. The untreated glass cloth was taken out and baked in an oven at 160° C. for 3 minutes to obtain a prepreg.

[0097] 4. Preparation of copper clad laminate

[0098] Four prepregs prepared in step 3 were stacked together, and then a copper foil was covered on each side of the stacked prepregs. The copper clad laminate was obtained by hot pressing at 180° C. and 2 MPa for 150 minutes.

[0099] Experimental test results:

[0100] 1. The DSC curves of polytetrafluoroethylene powder, polyperfluoroethylene propylene powder and modified polytetrafluoroethylene powder prepared in Example 1 were measured by differential scanning calorimetry. Figure 1 shown.

[0101] from Figure 1 From the comprehensive analysis of the DSC curve peaks, it can be seen that although the melting peak temperatures of PTFE and FEP are quite different, the melting characteristics of the blended materials are basically close to the melting characteristics of PTFE. The starting point temperature, peak temperature and end point temperature of the peak are reduced by 4-6°C accordingly. The thermal performance of such a mixed system meets the requirements. The heat resistance of the blended resin system is not reduced too much due to the addition of FEP with low thermal performance, and the flow properties of the blended resin system are greatly improved.

[0102] 2. Scanning electron microscope photographs of the impact cross section of the modified polytetrafluoroethylene powder material prepared in Example 1 were taken using a scanning electron microscope. Figure 2 shown.

[0103] Depend on Figure 2 From the scanning electron microscope photograph of the impact cross section of the modified polytetrafluoroethylene powder material, it can be seen that regular fibrous stripes appear on the fracture surface of the sample, the cross section is flat and uniform, and the cracks are dense.

[0104] In summary, Figure 1 and Figure 2This shows that polytetrafluoroethylene and polyperfluoroethylene propylene mixed materials have good compatibility.

[0105] 3. Performance comparison of FEP-modified PTFE copper clad laminate and ordinary PTFE copper clad laminate, as well as performance comparison of copper clad laminate using alkali-free glass cloth and ordinary untreated glass cloth, as shown in Table 1.

[0106] Test method: The glass transition temperature (DCS) is measured by a differential scanner from TA Instruments Waters, USA; the T288 thermal delamination time, solder heat resistance, and thermal expansion coefficient CTE (50-260°C, Z-axis) are measured by a thermomechanical analyzer from TA Instruments Waters, USA; the dielectric constant Dk (10GHz), dielectric constant Df (10GHz), dielectric constant Dk (5GHz), and dielectric constant Df (5GHz) are measured by a network analyzer from KEYSIGHT, USA. The above tests are all carried out in accordance with the IPC TM-650 standard in the copper clad laminate field.

[0107] Table 1 Experimental test data of each embodiment and comparative example

[0108]

[0109] The results in the table above show that, by comparing the test results of Example 1 with Comparative Example 1, it can be seen that the copper-clad laminate prepared with polytetrafluoroethylene modified with polytetrafluoroethylene has better performance than the copper-clad laminate prepared with unmodified polytetrafluoroethylene in all aspects, thereby demonstrating that the polytetrafluoroethylene modified with polytetrafluoroethylene of the present invention can indeed improve the various properties of the copper-clad laminate; by comparing Examples 1-2 with Comparative Examples 1-3, it can be seen that the various properties of Comparative Example 2 are the worst, indicating that both unmodified polytetrafluoroethylene and untreated glass cloth have an impact on the performance of the copper-clad laminate, thereby demonstrating the feasibility of the present invention; by comparing the test results of Comparative Example 3 with Example 1, it can be seen that the treated glass cloth (alkali-free glass cloth) does have better performance than the untreated glass cloth, thereby demonstrating that the treated glass cloth (alkali-free glass cloth) of the present invention can indeed improve the various properties of the copper-clad laminate.

[0110] In summary, the copper clad laminate prepared by the present invention has the characteristics of ultra-low dielectric loss and dielectric constant, high peel strength, low expansion coefficient and excellent heat resistance.

[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polytetrafluoroethylene (PTFE)-modified polytetrafluoroethylene resin composition, characterized in that: Calculated by weight, it includes the following components:

2. The polytetrafluoroethylene (PTFE)-modified polytetrafluoroethylene (PTFE) resin composition according to claim 1, wherein: The preparation method of the modified polytetrafluoroethylene powder comprises the following steps: Weigh polytetrafluoroethylene concentrated water dispersion emulsion and polyperfluoroethylene propylene concentrated dispersion in a weight ratio of 1:2 and place them in a beaker, add water and stir evenly at a speed of 450-500r / min, add acetone to precipitate, filter the coagulant with gauze, air-dry, and then dry in a vacuum oven at 100-110℃ for 20-24 hours, and then extract with acetone 7-10 times to obtain modified polytetrafluoroethylene powder.

3. The polytetrafluoroethylene resin composition modified with fluoroethylene propylene according to claim 1, characterized in that: The benzoxazine is any one of phenol-type benzoxazine resin, bisphenol A-type benzoxazine resin, bisphenol F-type benzoxazine resin, bisphenol S-type benzoxazine resin, phenolic benzoxazine resin, and diamine-type benzoxazine resin; the curing accelerator is one or more of boron trifluoride ethylamine, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, triphenylphosphine, tributylphosphine, and triethylphosphine; and the flame retardant is one or more of tetrabromobisphenol A, decabromodiphenyl ether, decabromodiphenyl ethane, and bromotriazine.

4. A resin glue, characterized in that: The polytetrafluoroethylene resin composition modified with fluoroethylene propylene according to any one of claims 1 to 3 is dissolved or dispersed in an organic solvent, wherein the organic solvent is 60-80 parts by weight and the organic solvent is one or more of toluene, xylene, acetone and butanone.

5. A prepreg, characterized in that: The resin adhesive according to claim 4 is used for preparation.

6. The prepreg according to claim 5, characterized in that The preparation method of the prepreg comprises the following steps: pouring the resin glue according to claim 4 into a clean flat plate, dipping the alkali-free glass cloth in the resin glue for 30-50 seconds, taking it out, and baking it in an oven at 160-180° C. for 3-5 minutes to obtain the prepreg.

7. The prepreg according to claim 6, wherein: The preparation method of the alkali-free glass cloth comprises the following steps: heating the glass cloth at 400-500°C for 20-30 minutes, impregnating the heat-treated glass cloth with a silane coupling agent surface modification liquid for 5-10 minutes, naturally air-drying the glass cloth, and baking the glass cloth at 110-120°C for 30-40 minutes to obtain the alkali-free glass cloth.

8. The prepreg according to claim 7, characterized in that: The silane coupling agent is KH-6032 silane coupling agent and / or tridecafluorooctyltriethoxysilane.

9. A copper clad laminate, characterized in that: The prepreg is prepared using the prepreg described in any one of claims 5 to 8.

10. The copper clad laminate according to claim 9, characterized in that: The preparation method of the copper clad laminate comprises the following steps: stacking 4-8 prepregs, then covering both sides of the stacked prepregs with a copper foil, and hot pressing at 180-200° C. and 2-5 MPa for 90-150 minutes to obtain the copper clad laminate.

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