Phenolic aldehyde curing high-thermal-conductivity copper-clad plate and preparation method thereof

Abstract

The invention relates to the technical field of heat conduction materials, in particular to a phenolic aldehyde curing high-heat-conduction copper-clad plate and a preparation method thereof. The preparation method comprises the following steps: mixing propargyl modified phenolic resin with bisphenol A epoxy resin, heating to 80-90 DEG C, adding a melamine modifier, and continuously reacting for 20-30 minutes to obtain composite resin; adding spherical silica powder, amino-modified nano aluminum oxide, a curing agent and a flatting agent into the composite resin, mixing, melting, extruding and granulating to prepare a powder adhesive; the method comprises the following steps: uniformly coating the surface of a dry glass fabric with a powder adhesive, and pre-curing at 130-140 DEG C to obtain a prepreg; and copper foil-prepreg-copper foil superposition and vacuum hot pressing are carried out, such that the high thermal conductivity copper-clad plate is obtained. The heat conductivity of the high-heat-conductivity copper-clad plate can reach 5.0 W / (m.K) or above; the peeling strength reaches 2.3 N / mm or above, the adhesive layer has no bubble defect, and the market requirements of high heat conduction, uniform heat conduction and good heat stability are met.

Description

Technical Field

[0001] This invention relates to the field of thermally conductive materials technology, specifically to a phenolic-cured high thermal conductivity copper-clad laminate and its preparation method. Background Technology

[0002] Copper clad laminate (CCL) is a core substrate for electronic circuits. Its thermal conductivity directly affects the heat dissipation efficiency and stability of electronic devices, and there is an urgent need for it, especially in high-power, highly integrated devices (such as 5G base stations and new energy vehicle electronics).

[0003] Traditional copper-clad laminates (CCLs) mostly use phenolic resin / epoxy resin systems, which offer good heat resistance and low cost, but are brittle and have insufficient thermal conductivity, making them unsuitable for the heat dissipation requirements of high-end equipment. High thermal conductivity CCLs need to balance thermal conductivity, heat resistance, mechanical strength, and insulation simultaneously; in addition, uneven dispersion of thermally conductive fillers and poor resin-filler interfacial compatibility are also major bottlenecks in existing technologies.

[0004] Therefore, effective research is needed on phenolic resin and thermally conductive fillers to obtain a copper-clad laminate with excellent performance. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a phenolic-cured high thermal conductivity copper clad laminate and its preparation method, wherein the high thermal conductivity copper clad laminate has the characteristics of high thermal conductivity, uniform thermal conductivity, and good thermal stability.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for preparing a phenolic-cured high thermal conductivity copper-clad laminate includes the following steps:

[0008] (1) Mix propargyl modified phenolic resin with bisphenol A epoxy resin, heat to 80-90℃, add melamine modifier and continue the reaction for 20-30 min to obtain composite resin;

[0009] (2) Spherical silica powder, amino-modified nano-alumina, curing agent and leveling agent are added to the composite resin and mixed. The mixture is then melt-extruded and granulated to form a powder adhesive. No volatile solvents are added throughout the process.

[0010] (3) The powdered adhesive is evenly coated on the surface of the dry fiberglass cloth and pre-cured at 130-140℃ to obtain a semi-cured sheet;

[0011] (4) Copper foil-prepreg-copper foil are stacked and vacuum hot-pressed to obtain a high thermal conductivity copper-clad laminate.

[0012] According to a preferred embodiment of the present invention, the preparation method of the propargyl modified phenolic resin is as follows: linear phenolic resin is mixed and stirred with DMF until the resin is completely dissolved, the temperature is raised to 50-80°C and maintained, a catalyst is added, propargyl bromide is added dropwise, and the reaction is carried out at a constant temperature of 80-100°C for 4-8 hours. After cooling, washing and drying, propargyl modified phenolic resin is obtained.

[0013] According to a preferred embodiment of the present invention, in step (1), the raw material components in the composite resin are, by mass parts: 60-70 parts of propargyl modified phenolic resin, 10-15 parts of bisphenol A epoxy resin, and 3-5 parts of melamine modifier.

[0014] According to a preferred embodiment of the present invention, the raw materials added in step (2) include, by mass parts: 40-50 parts of spherical silica powder, 5-8 parts of amino-modified nano alumina, 4-6 parts of curing agent and 1-2 parts of leveling agent.

[0015] According to a preferred embodiment of the present invention, the spherical silica powder is submicron in size and has a particle size of 1-3 μm.

[0016] According to a preferred embodiment of the present invention, the particle size of the powder adhesive obtained in step (2) is 50-80 μm.

[0017] According to a preferred embodiment of the present invention, the thickness of the powder adhesive applied in step (3) is 20-30 μm.

[0018] According to a preferred embodiment of the present invention, the pre-curing time in step (3) is 15-20 min.

[0019] According to a preferred embodiment of the present invention, the temperature of vacuum hot pressing in step (4) is 170-200℃, the pressure is 1.5-2.0MPa, and the heat and pressure holding time is 2-3 hours.

[0020] The present invention also provides a phenolic-cured high thermal conductivity copper-clad laminate obtained by the above preparation method.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. The phenolic-cured high thermal conductivity copper-clad laminate of the present invention has a thermal conductivity of 5.0 W / (mK) or higher and a peel strength of 2.3 N / mm or higher. The adhesive layer is free of bubble defects, which meets the market demand for high thermal conductivity, uniform thermal conductivity and good thermal stability.

[0023] 2. The preparation method of the phenolic-cured high thermal conductivity copper-clad laminate of the present invention uses propargyl-modified phenolic resin as the main matrix and adds a small amount of bisphenol A epoxy resin, which has both high thermal stability and excellent adhesion, thus improving the brittleness problem of ordinary phenolic resin; spherical silica micropowder and amino-modified nano-alumina are used as thermally conductive fillers. Spherical silica micropowder has the characteristic of low expansion, while amino-modified nano-alumina can participate in resin crosslinking to construct an efficient thermally conductive pathway; and environmentally friendly powder adhesive spraying combined with vacuum hot pressing is used instead of the existing solvent-based impregnation to avoid bubble defects in the adhesive layer and improve the uniformity of thermal conductivity. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0025] The preparation methods of the propargyl-modified phenolic resin and amino-modified nano-alumina used in the embodiments of the present invention are as follows:

[0026] Preparation method of propargyl modified phenolic resin:

[0027] 100g of linear phenolic resin was pulverized, and 450mL of DMF (N,N-dimethylformamide) was added to a reaction vessel. Then, the pulverized phenolic resin was added and stirred until the resin was completely dissolved. The temperature was raised to 50-80℃ and maintained. 5g of anhydrous potassium carbonate catalyst was added. Then, 15g of propargyl bromide was slowly added dropwise, and the reaction was carried out at 80-100℃ for 4-8 hours. The reaction solution was cooled to room temperature, and the precipitate was removed by filtration. The filtrate was poured into deionized water and stirred to precipitate the modified resin. The precipitate was collected by vacuum filtration. The product was washed 2-3 times alternately with deionized water and anhydrous ethanol. The product was dried under vacuum to obtain propargyl modified phenolic resin.

[0028] Preparation method of amino-modified nano-alumina: Nano-alumina powder is added to a mixture of anhydrous ethanol and deionized water (volume ratio 9:1), ultrasonically dispersed for 30 minutes, washed 2-3 times with anhydrous ethanol, centrifuged to collect the precipitate, and vacuum dried; 10g of dried powder is added to anhydrous ethanol, ultrasonically dispersed for 20 minutes to form a uniform suspension, the pH is adjusted to 4-5 with hydrochloric acid, the temperature is raised to 60-70℃, 1g of APTES (3-aminopropyltriethoxysilane) is slowly added, and the reaction is stirred for 4-6 hours; after the reaction is completed, the solid product is collected by centrifugation, washed, and vacuum dried.

[0029] The raw materials and reagents involved in the embodiments of this invention are all commercially available conventional reagents, and the experimental methods involved can all be implemented using existing technologies.

[0030] Example 1

[0031] (1) Add 60 parts of propargyl modified phenolic resin and 10 parts of bisphenol A epoxy resin to a reaction vessel and mix evenly. Heat to 80-90℃ and stir for 30 min. Add 3 parts of melamine modifier and continue to react for 20-30 min to obtain composite resin. Cool to room temperature and set aside.

[0032] (2) Add 40 parts of spherical silica powder, 5 parts of amino-modified nano alumina, 4 parts of curing agent (2-(4-aminophenyl)-5-aminobenzimidazole) and 1 part of leveling agent (modified acrylate) to the composite resin and mix them. Then, make a powder adhesive with a particle size of 50-80 μm by melt extrusion granulation. No volatile solvents are added throughout the process.

[0033] (3) Select electronic grade fiberglass cloth, dry it at 120℃ for 2 hours to remove moisture, and use electrostatic spraying to evenly coat the powder adhesive on the surface of the dry fiberglass cloth. The coating thickness is controlled at 20-30μm; then pre-cur it at 130-140℃ to obtain a semi-cured sheet.

[0034] (4) The copper foil-prepreg-copper foil are stacked and placed in a vacuum hot press. The temperature is raised to 170-200℃ in a vacuum environment, and the pressure is increased to 1.5-2.0MPa. The heat and pressure are maintained for 2-3 hours to complete the curing and molding, and a high thermal conductivity copper-clad laminate is obtained.

[0035] Example 2

[0036] (1) Add 70 parts of propargyl modified phenolic resin and 15 parts of bisphenol A epoxy resin to a reaction vessel and mix evenly. Heat to 85°C and stir for 30 min. Add 5 parts of melamine modifier and continue to react for 30 min to obtain composite resin. Cool to room temperature and set aside.

[0037] (2) Add 50 parts of spherical silica powder, 8 parts of amino-modified nano alumina, 6 parts of curing agent (2-(4-aminophenyl)-5-aminobenzimidazole) and 2 parts of leveling agent (modified acrylate) to the composite resin and mix them. Then, make a powder adhesive with a particle size of 50-80μm by melt extrusion granulation. No volatile solvents are added throughout the process.

[0038] (3) Select electronic grade fiberglass cloth, dry it at 120℃ for 2 hours to remove moisture, and use electrostatic spraying to evenly coat the powder adhesive on the surface of the dry fiberglass cloth. The coating thickness is controlled at 20-30μm; then pre-cur it at 130-140℃ to obtain a semi-cured sheet.

[0039] (4) The copper foil-prepreg-copper foil are stacked and placed in a vacuum hot press. The temperature is raised to 170-200℃ in a vacuum environment, and the pressure is increased to 1.5-2.0MPa. The heat and pressure are maintained for 3 hours to complete the curing and molding, and a high thermal conductivity copper-clad laminate is obtained.

[0040] Example 3

[0041] (1) Add 65 parts of propargyl modified phenolic resin and 12 parts of bisphenol A epoxy resin to a reaction vessel and mix evenly. Heat to 90°C and stir for 30 min. Add 3 parts of melamine modifier and continue to react for 20 min to obtain composite resin. Cool to room temperature and set aside.

[0042] (2) Add 45 parts of spherical silica powder, 6 parts of amino-modified nano alumina, 5 parts of curing agent (2-(4-aminophenyl)-5-aminobenzimidazole) and 1 part of leveling agent (modified acrylate) to the composite resin and mix them. Then, make a powder adhesive with a particle size of 50-80 μm by melt extrusion granulation. No volatile solvents are added throughout the process.

[0043] (3) Select electronic grade fiberglass cloth, dry it at 120℃ for 2 hours to remove moisture, and use electrostatic spraying to evenly coat the powder adhesive on the surface of the dry fiberglass cloth. The coating thickness is controlled at 20-30μm; then pre-cur it at 130-140℃ to obtain a semi-cured sheet.

[0044] (4) The copper foil-prepreg-copper foil are stacked and placed in a vacuum hot press. The temperature is raised to 170-200℃ in a vacuum environment, and the pressure is increased to 1.5-2.0MPa. The heat and pressure are maintained for 2-3 hours to complete the curing and molding, and a high thermal conductivity copper-clad laminate is obtained.

[0045] Comparative Example 1

[0046] (1) Add 65 parts of propargyl modified phenolic resin and 12 parts of bisphenol A epoxy resin to a reaction vessel and mix evenly. Heat to 90°C and stir for 30 min. Add 3 parts of melamine modifier and continue to react for 20 min to obtain composite resin. Cool to room temperature and set aside.

[0047] (2) Add 45 parts of spherical silica powder, 6 parts of amino-modified nano alumina, 5 parts of curing agent (2-(4-aminophenyl)-5-aminobenzimidazole) and 1 part of leveling agent (modified acrylate) to the composite resin and mix them to obtain the impregnation solution.

[0048] (3) Select electronic grade fiberglass cloth, dry it at 120°C for 2 hours to remove moisture, immerse it in impregnation solution, and then cover it with copper foil and press it into shape.

[0049] Comparative Example 2

[0050] (1) Add 65 parts of linear phenolic resin to the reaction vessel and mix evenly. Heat to 90℃ and stir for 30 min. Add 3 parts of melamine modifier and continue to react for 20 min to obtain composite resin. Cool to room temperature and set aside. The preparation method of linear phenolic resin is as follows: Put phenol and paraformaldehyde into the reaction vessel at a molar ratio of 1:1.1, adjust the pH to 5, heat to 95℃ and keep warm for 40 min. After the reaction is completed, cool to 30℃ within 15 min to obtain linear phenolic resin.

[0051] (2) Add 45 parts of spherical silica powder, 6 parts of amino-modified nano alumina, 5 parts of curing agent (2-(4-aminophenyl)-5-aminobenzimidazole) and 1 part of leveling agent (modified acrylate) to linear phenolic resin and mix them. Then, make a powder adhesive with a particle size of 50-80 μm by melt extrusion granulation. No volatile solvents are added throughout the process.

[0052] (3) Select electronic grade fiberglass cloth, dry it at 120℃ for 2 hours to remove moisture, and use electrostatic spraying to evenly coat the powder adhesive on the surface of the dry fiberglass cloth. The coating thickness is controlled at 20-30μm; then pre-cur it at 130-140℃ to obtain a semi-cured sheet.

[0053] (4) The copper foil-prepreg-copper foil are stacked and placed in a vacuum hot press. The temperature is raised to 170-200℃ in a vacuum environment, and the pressure is increased to 1.5-2.0MPa. The heat and pressure are maintained for 2-3 hours to complete the curing and molding, and a high thermal conductivity copper-clad laminate is obtained.

[0054] Comparative Example 3

[0055] (1) Add 65 parts of propargyl modified phenolic resin and 12 parts of bisphenol A epoxy resin to a reaction vessel and mix evenly. Heat to 90°C and stir for 30 min. Add 3 parts of melamine modifier and continue to react for 20 min to obtain composite resin. Cool to room temperature and set aside.

[0056] (2) Add 50 parts of spherical silica powder, 5 parts of 2-(4-aminophenyl)-5-aminobenzimidazole and 1 part of modified acrylate leveling agent to the composite resin and mix them. Then, make a powder adhesive with a particle size of 50-80 μm by melt extrusion granulation. No volatile solvents are added throughout the process.

[0057] (3) Select electronic grade fiberglass cloth, dry it at 120℃ for 2 hours to remove moisture, and use electrostatic spraying to evenly coat the powder adhesive on the surface of the dry fiberglass cloth. The coating thickness is controlled at 20-30μm; then pre-cur it at 130-140℃ to obtain a semi-cured sheet.

[0058] (4) The copper foil-prepreg-copper foil are stacked and placed in a vacuum hot press. The temperature is raised to 170-200℃ in a vacuum environment, and the pressure is increased to 1.5-2.0MPa. The heat and pressure are maintained for 2-3 hours to complete the curing and molding, and a high thermal conductivity copper-clad laminate is obtained.

[0059] Comparative Example 4

[0060] (1) Add 65 parts of propargyl modified phenolic resin and 12 parts of bisphenol A epoxy resin to a reaction vessel and mix evenly. Heat to 90°C and stir for 30 min. Add 3 parts of melamine modifier and continue to react for 20 min to obtain composite resin. Cool to room temperature and set aside.

[0061] (2) Add 8 parts of amino-modified nano alumina, 5 parts of 2-(4-aminophenyl)-5-aminobenzimidazole and 1 part of modified acrylate leveling agent to the composite resin and mix them. Then, make a powder adhesive with a particle size of 50-80μm by melt extrusion granulation. No volatile solvents are added throughout the process.

[0062] (3) Select electronic grade fiberglass cloth, dry it at 120℃ for 2 hours to remove moisture, and use electrostatic spraying to evenly coat the powder adhesive on the surface of the dry fiberglass cloth. The coating thickness is controlled at 20-30μm; then pre-cur it at 130-140℃ to obtain a semi-cured sheet.

[0063] (4) The copper foil-prepreg-copper foil are stacked and placed in a vacuum hot press. The temperature is raised to 170-200℃ in a vacuum environment, and the pressure is increased to 1.5-2.0MPa. The heat and pressure are maintained for 2-3 hours to complete the curing and molding, and a high thermal conductivity copper-clad laminate is obtained.

[0064] The performance of the copper-clad laminates prepared in Examples 1-3 and Comparative Examples 1-4 was tested:

[0065] The peel strength of copper-clad laminates after 125° thermal stress was tested in accordance with GB4722-2017.

[0066] Thermal conductivity was tested using the LW9090IR thermal conductivity meter from Ruiling Technology Co., Ltd.

[0067] Heat resistance was tested by immersion tin method, in which the sample was immersed in tin at 288°C for 10 seconds at a time until delamination occurred.

[0068] The specific test results are shown in Table 1:

[0069] Table 1 project Peel strength / N / mm Thermal conductivity / W / (m·K) Heat resistance / cycles Example 1 2.5 5.2 ＞30 Example 2 2.4 5.0 ＞30 Example 3 2.3 5.3 ＞30 Comparative Example 1 1.8 2.9 22 Comparative Example 2 1.5 3.1 18 Comparative Example 3 1.7 2.7 24 Comparative Example 4 1.4 3.3 20

[0070] As can be seen from the above results, this invention optimizes the raw material composition and preparation method, using propargyl-modified phenolic resin with a small amount of bisphenol A epoxy resin as the main matrix, and spherical silica micropowder and amino-modified nano-alumina as thermally conductive fillers; it uses environmentally friendly powder adhesive spraying combined with vacuum hot pressing instead of the existing solvent-based impregnation, avoiding bubble defects in the adhesive layer and improving the uniformity of thermal conductivity. The phenolic-cured high thermal conductivity copper-clad laminates obtained in Examples 1-3 have a thermal conductivity of over 5.0 W / (m·K) and a peel strength of over 2.3 N / mm, with no bubble defects in the adhesive layer, meeting the market demand for high thermal conductivity, uniform thermal conductivity, good thermal stability, and high strength.

[0071] The performance of Comparative Examples 1-4 is lower than that of Examples 1-3. In Comparative Example 1, the method of impregnating with adhesive solution inevitably results in bubble defects, affecting thermal conductivity and uniformity, and thus the thermal conductivity is relatively poor. Comparative Example 2 uses ordinary linear phenolic resin as the matrix material, which is more brittle and its strength will be reduced. Comparative Examples 3 and 4 use spherical silica powder or amino-modified nano-alumina as thermally conductive fillers, respectively. Compared with the examples, the thermal conductivity and thermal stability will be affected to a certain extent.

[0072] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a phenolic-cured high thermal conductivity copper-clad laminate, characterized in that, Includes the following steps: (1) Mix propargyl modified phenolic resin with bisphenol A epoxy resin, heat to 80-90℃, add melamine modifier and continue the reaction for 20-30 min to obtain composite resin; (2) Add spherical silica powder, amino-modified nano-alumina, curing agent and leveling agent to the composite resin and mix them, then melt extrude and granulate to make a powder adhesive; (3) The powdered adhesive is evenly coated on the surface of the dry fiberglass cloth and pre-cured at 130-140℃ to obtain a semi-cured sheet; (4) Copper foil-prepreg-copper foil are stacked and vacuum hot-pressed to obtain a high thermal conductivity copper-clad laminate.

2. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, The preparation method of the propargyl modified phenolic resin is as follows: linear phenolic resin is mixed and stirred with DMF until the resin is completely dissolved, the temperature is raised to 50-80℃ and maintained, a catalyst is added, propargyl bromide is added dropwise, and the reaction is carried out at a constant temperature of 80-100℃ for 4-8 hours. After cooling, washing and drying, propargyl modified phenolic resin is obtained.

3. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, In step (1), the raw material components in the composite resin are, by mass, 60-70 parts of propargyl modified phenolic resin, 10-15 parts of bisphenol A epoxy resin, and 3-5 parts of melamine modifier.

4. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, The raw materials added in step (2) include, by mass parts: 40-50 parts of spherical silica powder, 5-8 parts of amino-modified nano alumina, 4-6 parts of curing agent and 1-2 parts of leveling agent.

5. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, The spherical silica powder is submicron in size, with a particle size of 1-3 μm.

6. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, The powder adhesive obtained in step (2) has a particle size of 50-80 μm.

7. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, The thickness of the powder adhesive applied in step (3) is 20-30 μm.

8. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, The pre-curing time in step (3) is 15-20 minutes.

9. The method for preparing a phenolic-cured high thermal conductivity copper-clad laminate according to claim 1, characterized in that, In step (4), the temperature of vacuum hot pressing is 170-200℃, the pressure is 1.5-2.0MPa, and the heat and pressure holding time is 2-3 hours.

10. The high thermal conductivity copper-clad laminate obtained by any one of claims 1-9.