Low-hardness heat-conducting powder material for copper-clad plate and preparation method of low-hardness heat-conducting powder material

Abstract

The invention relates to a low-hardness heat-conducting powder material for a copper-clad plate, which is characterized in that the powder material comprises the following components: 50-90% of zinc aluminate; the powder A is one or two of aluminum powder and magnesium powder, and the content of the powder A is 10-50%; the invention also discloses a preparation method of the low-hardness heat-conducting powder material for the copper-clad plate. According to the prepared low-hardness heat-conducting powder material for the copper-clad plate, the cumulative 50% particle size (D50) of the laser diffraction scattering particle size distribution measurement volume standard is 5-150 microns, the sphericity degree read by a microscopic particle imager is 0.95-1.00, the heat conductivity tested by a DRL-III heat conductivity coefficient tester is larger than 1.3 W / m.K, a drill bit of 0.3 mm is used for drilling a heat-conducting gasket, the abrasion condition is judged according to the weight loss of the drill bit, and the heat conductivity of the copper-clad plate is judged according to the weight loss of the drill bit. After 5000 holes are continuously drilled, the wear rate of the drill bit is less than 0.1%.

Description

Technical Field

[0001] The present invention relates to a heat-conducting powder material, in particular to a low-hardness heat-conducting powder material for copper clad laminates, and the present invention also relates to a preparation method of the foregoing material. Background Art

[0002] With the continuous improvement of the power and integration of electronic components, the heat generation power also increases synchronously, thus the requirements for heat-conducting materials are getting higher and higher. At present, common heat-conducting fillers include alumina, magnesia, zinc oxide, aluminum nitride, boron nitride, and so on. Aluminum nitride and boron nitride have high heat-conducting coefficients but are expensive. Alumina has a high heat-conducting coefficient but high hardness, which is easy to cause wear of equipment such as mixers and molding machines. The heat-conducting coefficient of zinc oxide is comparable to that of alumina, and its Mohs hardness is much lower than that of alumina, but the boiling point of zinc oxide is higher than its melting point, making it difficult to prepare spherical zinc oxide products. Zinc aluminate (spinel) has good corrosion resistance, wear resistance and chemical stability, and has good insulation, a small thermal expansion coefficient and good heat conductivity, and is widely used as an insulating skeleton of electronic components, a ceramic protective film for alloys or metal products, etc. Currently, common zinc aluminate powders are mostly nano-scale spherical and micron-scale spherical-like powders, which are difficult to achieve high heat-conducting effects through high-proportion filling and cannot be applied to fields such as copper clad laminates.

[0003] The published patent document CN112209423B uses Zn(NO3)2·6H2O and Al(NO3)3·9H2O as raw materials to prepare hollow zinc aluminate particles of about 3μm through a flame synthesis method. The zinc aluminate obtained by this method has a low particle size and is a hollow particle, and the product can only be applied to flame retardants, with a small particle size and low heat conductivity.

[0004] The published patent document CN 115521731A uses γ-alumina and zinc oxide as raw materials to develop zinc aluminate particles of 1-10μm through processes such as ball milling. The product has poor sphericity, and the filling amount can only reach about 70%, and the heat conductivity is low. Summary of the Invention

[0005] The purpose of the present invention is to provide a low-hardness heat-conducting powder material for copper clad laminates to solve the problems of low particle size of zinc aluminate and inefficient filling. The material is a micron-scale spherical zinc aluminate composite product with high sphericity and low hardness that can be applied to the field of copper clad laminates.

[0006] Another purpose of the present invention is to also provide a preparation method of the foregoing low-hardness heat-conducting powder material for copper clad laminates.

[0007] The purpose of the present invention is achieved through the following technical solutions. The present invention is a low-hardness heat-conducting powder material for copper clad laminates, characterized in that the composition of the powder material is as follows:

[0008] Zinc aluminate: content 50-90%;

[0009] Powder A: one or both of aluminum powder and magnesium powder, with a content of 10% - 50%.

[0010] For the low-hardness and high-thermal-conductivity powder material described above in the present invention, a further preferred technical solution is that the composition of the powder material is:

[0011] Zinc aluminate: content 90%;

[0012] Powder A: aluminum powder or magnesium powder, with a content of 10%.

[0013] For the low-hardness and high-thermal-conductivity powder material described above in the present invention, a further preferred technical solution is that the composition of the powder material is:

[0014] Zinc aluminate: content 70%;

[0015] Powder A: aluminum powder or magnesium powder, with a content of 30%.

[0016] The present invention also discloses a preparation method of a low-hardness and thermal-conductivity powder material for a copper clad laminate, which is characterized in that the steps are as follows:

[0017] (1) Add zinc aluminate into water, stir to obtain a slurry with a uniformly mixed solid content of 10% - 40%; spray-dry the slurry to obtain spherical zinc aluminate aggregates with D50 = 5 - 150 μm;

[0018] (2) After uniformly mixing the zinc aluminate aggregates and Powder A in a ratio of 5:5 - 9:1, perform heat treatment at 600°C - 800°C, so that Powder A forms a molten state under high-temperature conditions and hybridizes with zinc aluminate particles to form a composite oxide B;

[0019] (3) Put the composite oxide B into a spheroidizing device for spheroidizing treatment to obtain a spherical zinc aluminate composite product with D50 = 5 - 150 μm.

[0020] For the preparation method of a low-hardness and thermal-conductivity powder material for a copper clad laminate described in the present invention, a further preferred technical solution is that in step (1): the solid content of the zinc aluminate slurry is 10% - 20%.

[0021] For the preparation method of a low-hardness and thermal-conductivity powder material for a copper clad laminate described in the present invention, a further preferred technical solution is that in step (2): the mixing ratio of the zinc aluminate aggregates and Powder A is 7:3 - 9:1.

[0022] For the preparation method of a low-hardness and thermal-conductivity powder material for a copper clad laminate described in the present invention, a further preferred technical solution is that in step (3): the carrier gas is nitrogen, the combustion-supporting gas is air or oxygen, and the fuel is natural gas;

[0023] A preparation method of a low-hardness thermally conductive powder material for a copper clad laminate, and a further preferred technical solution is that in step (3): the spheroidization temperature is 1200-1400 °C.

[0024] A preparation method of a low-hardness thermally conductive powder material for a copper clad laminate, and a further preferred technical solution is that in step (3): the particle size of the spherical zinc aluminate composite product is 5-50 μm.

[0025] The performance of the present invention can be tested by the following method:

[0026] Mix the spherical zinc aluminate composite product prepared by the present invention with vinyl silicone oil in a ratio of 90:10 to 80:20, disperse it using a planetary ball mill, add a certain amount of hydrogen-containing silicone oil, curing agent and inhibitor, mix evenly by mechanical stirring, and then perform vacuum degassing to remove the bubbles in the mixture; use a calender to press and mold to obtain a 3 mm thick thermally conductive gasket, and use a DRL-III thermal conductivity tester to test the thermal conductivity. The thermal conductivity of the product of the present invention is greater than 1.3 W / m·K; drill holes in the thermally conductive gasket using a 0.3 mm drill bit at a drilling speed of 3000 rpm, continuously drill 5000 holes, and judge the degree of drill bit wear by the weight loss of the drill bit before and after use. The loss rate of the product of the present invention is less than 0.2%.

[0027] The key point of the present invention is that: the melting point of zinc aluminate is 1200 °C and the decomposition temperature is 1600 °C. During the high-temperature spheroidization process, if the temperature is too high, it is easy to decompose into alumina and zinc oxide, and the boiling point of zinc oxide is 1800 °C. Therefore, the present invention forms a composite oxide by coating with aluminum powder and / or magnesium powder and melting at high temperature, which improves the decomposition temperature of the composite oxide while increasing the thermal conductivity. Compared with alumina powder, the product of the present invention has high thermal conductivity and low hardness. After 85% filling, the thermal conductivity of the composite oxide of this patent is greater than 1.3 W / m·K, and the drill bit wear rate is lower than 0.04%.

[0028] Compared with the prior art, the beneficial effects of the present invention are:

[0029] The high-thermal-conductivity spherical zinc aluminate powder prepared by the present invention has a cumulative 50% particle size (D50) of 5-150 μm measured by laser diffraction scattering particle size distribution on a volume basis, a sphericity of 0.95-1.00 read by a microscopic particle imager, a thermal conductivity greater than 1.3 W / m·K tested by a DRL-III thermal conductivity tester, drill holes in the thermally conductive gasket using a 0.3 mm drill bit, judge the wear condition by the weight loss of the drill bit, and the drill bit wear rate <0.1% after continuously drilling 5000 holes. The product is particularly suitable for thermally conductive adhesives, thermally conductive plastic encapsulants, etc. that require thermal conductivity performance. Specific embodiments

[0030] The specific technical solutions of the present invention are further described below to facilitate those skilled in the art to further understand the present invention without restricting its rights.

[0031] Example 1

[0032] Zinc aluminate raw materials with D50 = 0.01 μm are mixed with pure water at a ratio of 2:8, and zinc aluminate agglomerates A with D50 = 6 μm are obtained through spray drying; the agglomerates A are mixed with aluminum powder at a ratio of 9:1 and then heat-treated in a high-temperature device and subjected to spheroidization treatment to obtain a composite oxide with D50 = 6 μm (an oxide of aluminum-coated zinc aluminate).

[0033] The composite oxide is mixed with vinyl silicone oil at a ratio of 80 + 20, and its thermal conductivity is measured to be 1.2412 W / m·K; the bit wear rate is 0.021% after continuously drilling 5000 holes.

[0034] Example 2

[0035] Zinc aluminate raw materials with D50 = 0.01 μm are mixed with pure water at a ratio of 3:7, and zinc aluminate agglomerates A with D50 = 16 μm are obtained through spray drying and spheroidization treatment; the agglomerates A are mixed with aluminum powder at a ratio of 9:1 and then heat-treated in a high-temperature device and subjected to spheroidization treatment to obtain a composite oxide with D50 = 16 μm.

[0036] The composite oxide is mixed with vinyl silicone oil at a ratio of 85 + 15, and its thermal conductivity is measured to be 1.5673 W / m·K; the bit wear rate is 0.025% after continuously drilling 5000 holes.

[0037] Example 3

[0038] Zinc aluminate raw materials with D50 = 0.01 μm are mixed with pure water at a ratio of 3:7, and zinc aluminate agglomerates A with D50 = 16 μm are obtained through spray drying and spheroidization treatment; the agglomerates A are mixed with aluminum powder at a ratio of 7:3 and then heat-treated in a high-temperature device and subjected to spheroidization treatment to obtain a composite oxide with D50 = 16 μm.

[0039] The composite oxide is mixed with vinyl silicone oil at a ratio of 85 + 15, and its thermal conductivity is measured to be 1.6187 W / m·K; the bit wear rate is 0.031% after continuously drilling 5000 holes.

[0040] Example 4

[0041] Mix the zinc aluminate raw material with D50 = 0.1 μm and pure water in a ratio of 4:6, and obtain zinc aluminate agglomerate A with D50 = 32 μm through spray drying and spheroidization treatment; mix agglomerate A with aluminum powder in a ratio of 7:3, and then conduct heat treatment in a high-temperature device and obtain a composite oxide with D50 = 32 μm through spheroidization treatment.

[0042] Mix the composite oxide with vinyl silicone oil in a ratio of 85+15, and test its thermal conductivity to be 1.7411 W / m·K; the drill bit wear rate is 0.033% after continuously drilling 5000 holes.

[0043] Example 5

[0044] Mix the zinc aluminate raw material with D50 = 1 μm and pure water in a ratio of 4:6, and obtain zinc aluminate agglomerate A with D50 = 37 μm through spray drying and spheroidization treatment; mix agglomerate A with magnesium powder in a ratio of 7:3, and then conduct heat treatment in a high-temperature device and obtain a composite oxide (oxide of magnesium-coated zinc aluminate) with D50 = 37 μm through spheroidization treatment.

[0045] Mix the composite oxide with vinyl silicone oil in a ratio of 87+13, and test its thermal conductivity to be 1.8207 W / m·K; the drill bit wear rate is 0.039% after continuously drilling 5000 holes.

[0046] Example 6

[0047] Mix the zinc aluminate raw material with D50 = 1.0 μm and pure water in a ratio of 5:5, and obtain zinc aluminate agglomerate A with D50 = 56 μm through spray drying and spheroidization treatment; mix agglomerate A with magnesium powder in a ratio of 9:1, and then conduct heat treatment in a high-temperature device and obtain a composite oxide (oxide of magnesium-coated zinc aluminate) with D50 = 56 μm through spheroidization treatment.

[0048] Mix the composite oxide with vinyl silicone oil in a ratio of 91+9, and test its thermal conductivity to be 1.9939 W / m·K; the drill bit wear rate is 0.044% after continuously drilling 5000 holes.

[0049] Comparative Example 1

[0050] Mix alumina with 99% alumina content and D50 = 16 μm with vinyl silicone oil in a ratio of 85+15, the thermal conductivity of the obtained product is 1.4826 W / m·K, and the drill bit wear rate is 0.125% after continuously drilling 5000 holes.

[0051] Comparative Example 2

[0052] Zinc aluminate with a zinc aluminate content of 99% and D50 = 1.1 μm was mixed with vinyl silicone oil in a ratio of 80 + 20. The compatibility between the two was poor and they could not be dispersed.

[0053] Comparative Example 3

[0054] A product of hollow zinc aluminate with a zinc aluminate content of 99% and D50 = 5 μm was mixed with vinyl silicone oil in a ratio of 80 + 20. The thermal conductivity of the resulting product was 0.8549 W / m·K, and the bit wear rate was 0.011% after continuously drilling 5000 holes.

[0055]

[0056] It can be seen from the above comparative experiments that:

[0057] 1. Compared with Comparative Example 1 of the examples, in Example 2, as the particle size increased, the thermal conductivity of the product increased, and the bit wear rate was comparable;

[0058] 2. Comparing Example 2 with Example 3, and Example 4 with Example 5, under the condition of comparable particle sizes, as the filling ratio increased, both the thermal conductivity and the bit wear rate increased;

[0059] 3. Compared with Comparative Example 1 (only alumina), the thermal conductivity of Example 3 (zinc aluminate composite oxide) was higher and the bit wear rate was lower;

[0060] 4. Compared with Example 1, in Comparative Example 2, the use of 1 μm zinc aluminate raw material could not achieve 80% filling. In Example 3, the use of 5 μm zinc aluminate raw material had a low bit wear rate after 80% filling, but the thermal conductivity was also low.

Claims

1. A low-hardness thermal conductive powder material for copper clad laminates, characterized in that, The composition of the powder material is as follows: Zinc aluminate: content 50 - 90%; Powder A: one or both of aluminum powder and magnesium powder, content 10% - 50%.

2. The low-hardness heat-conducting powder material for copper clad laminates according to claim 1, characterized in that, The composition of the powder material is as follows: Zinc aluminate: content 90%; Powder A: aluminum powder or magnesium powder, content 10%.

3. The low-hardness heat-conducting powder material for copper clad laminates according to claim 1, characterized in that, The composition of the powder material is as follows: Zinc aluminate: content 70%; Powder A: aluminum powder or magnesium powder, content 30%.

4. The preparation method of a low-hardness heat-conducting powder material for a copper clad laminate according to claim 1 or 2 or 3, characterized in that, The steps are as follows: (1) Add zinc aluminate into water and stir to obtain a slurry with a uniformly mixed solid content of 10% - 40%; spray-dry the slurry to obtain spherical zinc aluminate agglomerates with D50 = 5 - 150 μm; (2) After uniformly mixing the zinc aluminate agglomerates and Powder A in a ratio of 5:5 - 9:1, conduct heat treatment at 600°C - 800°C to make Powder A form a molten state under high-temperature conditions and hybridize with zinc aluminate particles to form composite oxide B; (3) Put the composite oxide B into a spheroidizing device for spheroidizing treatment to obtain spherical zinc aluminate composite products with D50 = 5 - 150 μm.

5. The preparation method of a low-hardness heat-conducting powder material for a copper clad laminate according to claim 4, wherein, In step (1): the solid content of the zinc aluminate slurry is 10% - 20%.

6. The preparation method of a low-hardness heat-conducting powder material for a copper clad laminate according to claim 4, characterized in that, In step (2): the mixing ratio of the zinc aluminate agglomerates and Powder A is 7:3 - 9:

1.

7. The preparation method of a low-hardness heat-conducting powder material for a copper clad laminate according to claim 4, wherein, In step (3): the carrier gas is nitrogen, the combustion-supporting gas is air or oxygen, and the fuel is natural gas.

8. The preparation method of a low-hardness heat-conducting powder material for a copper clad laminate according to claim 4, wherein, In step (3): the spheroidizing temperature is 1200 - 1400°C.

9. The preparation method of a low-hardness heat-conducting powder material for a copper clad laminate according to claim 4, characterized in that, In step (3): the particle size of the spherical zinc aluminate composite products is 5 - 50 μm.

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