Thermally-conductive silicone-coated fabric with low thermal contact resistance, and manufacturing method therefor

Abstract

Disclosed in the present invention is a thermally-conductive silicone-coated fabric with low thermal contact resistance. Raw materials for the manufacturing comprise, in parts by weight, 15-50 parts of modified polysiloxane, 120-550 parts of an inorganic powder, 0.1-0.5 part of a lubricating additive, and 0.2-45 parts of a diluent. In the present invention, the thermally-conductive powder prepared from alumina having different shapes and particle sizes in cooperation with each other has relatively low thermal contact resistance and relatively high thermal conductivity, so that using a low dosage of the thermally-conductive powder can enable a relatively high thermal conduction efficiency. In addition, the present invention uses a coating process, the viscosity before forming is low, and fillers are mixed with high uniformity, thus facilitating the processing; and a manufactured product exhibits good surface flatness, thickness tolerance and product uniformity. Said silicone-coated fabric has high reliability and insulativity, is soft and elastic and has low thermal contact resistance and high thermal conductivity, and therefore can be widely applied to the fields of switching-mode power supplies, communication devices, computers, flat-panel televisions, mobile devices, video devices, network products, household appliances, etc.

Description

A kind of low contact thermal resistance thermal conductive silicone cloth and preparation method thereof Technical Field

[0001] The present invention relates to a low-contact thermal resistance heat-conducting silicone cloth and a preparation method thereof, and relates to C08L, in particular to the field of compositions of polymer compounds. Background Art

[0002] With the development of science and technology, there are more and more functional demands on electronic products, and the functional integration of electronic products is increasing, resulting in higher heat dissipation of electronic products when working. If the generated heat cannot be dissipated in time, it will cause internal damage to the electronic products and affect the service life of the electronic products. The existing heat dissipation methods mostly use the installation of radiators to conduct heat, but there is still a certain heat dissipation resistance at the connection interface between the electronic product and the radiator. Therefore, the development of a connection material with good heat dissipation performance is crucial for highly integrated electronic products. Current heat dissipation connection materials are mostly optimized in terms of the particle size of the heat dissipation powder. Nano-scale heat dissipation powder has good heat dissipation effect and high thermal conductivity, but nano-scale heat dissipation powder is easy to agglomerate and will increase the consistency of the connection material, increase the difficulty of construction, and therefore the production cost is high.

[0003] Chinese invention patent CN201610119396.0 discloses a thermally conductive composite material and a thermally conductive sheet made of the material and a preparation method thereof. The particle size and morphology of a variety of thermally conductive fillers are selected, and the surface wettability is balanced and optimized to achieve excellent thermal conductivity while maintaining the safety, resilience and flexibility of the material itself. However, multiple fillers are required to work together, and the fillers also contain metal powder, which reduces the insulation performance of the material. Chinese invention patent CN201310408997.X discloses a method for preparing an insulating and highly thermally conductive composite material. Inorganic particles of a specific type and particle size are used as composite thermally conductive fillers, which are added to a crystalline polymer matrix to form a composite material with more thermal conductive pathways than a single filler. This can significantly improve the thermal conductivity of the material, but the hardness of the composite material formed is relatively high, which limits the scope of use of the material.

[0004] Summary of the Invention

[0005] In order to reduce the contact thermal resistance of silicone cloth and improve the insulation performance, the first aspect of the present invention provides a low contact thermal resistance thermal conductive silicone cloth, the preparation raw materials include, by weight: 15-50 parts of modified polysiloxane, 120-550 parts of inorganic powder, 0.1-0.5 parts of lubricating agent, and 0.2-45 parts of diluent.

[0006] As a preferred embodiment, the modified polysiloxane is selected from one or a combination of double-bond modified polysiloxane and hydrogenated modified polysiloxane.

[0007] As a preferred embodiment, the modified polysiloxane has a viscosity of 30-550,000 mPa·s at 25°C.

[0008] As a preferred embodiment, the modified polysiloxane has a viscosity of 40-350,000 mPa·s at 25°C.

[0009] As a preferred embodiment, the inorganic powder is selected from one or a combination of metal oxides, metal nitrides, non-metal oxides, non-metal carbides, and non-metal nitrides.

[0010] As a preferred embodiment, the particle size of the metal oxide is 0.05-90 μm, and the particle size of the non-metal nitride is 3-15 μm.

[0011] As a preferred embodiment, the inorganic powder is a combination of metal oxide and non-metal nitride, and the weight ratio of the metal oxide to the non-metal nitride is (145-165):10.

[0012] As a preferred embodiment, the metal oxide is selected from one or a combination of aluminum oxide, zinc oxide, and magnesium oxide.

[0013] As a preferred embodiment, the non-metallic nitride is selected from silicon nitride, boron nitride or a combination of several thereof.

[0014] As a preferred embodiment, the inorganic powder is a combination of aluminum oxide and boron nitride.

[0015] As a preferred embodiment, the aluminum oxide is a combination of spherical aluminum oxide and ellipsoidal aluminum oxide.

[0016] As a preferred embodiment, the particle size of the spherical alumina is 3-10 μm, and the particle size of the ellipsoidal alumina is 0.1-1 μm.

[0017] As a preferred embodiment, the alumina is a combination of spherical alumina with a particle size of 5-10 μm, spherical alumina with a particle size of 3-5 μm, and ellipsoidal alumina with a particle size of 0.1-1 μm.

[0018] As a preferred embodiment, the alumina is a combination of spherical alumina with a particle size of 10 μm, spherical alumina with a particle size of 3 μm, and ellipsoidal alumina with a particle size of 0.5 μm.

[0019] As a preferred embodiment, the weight ratio of the spherical alumina with a particle size of 10 μm, the spherical alumina with a particle size of 3 μm, and the ellipsoidal alumina with a particle size of 0.5 μm is (90-100): (30-50): (10-25).

[0020] As a preferred embodiment, the particle size of the boron nitride is 5-10 μm.

[0021] As a preferred embodiment, the diluent is selected from one or a combination of n-hexane, methanol, n-butane, toluene, xylene, cyclohexanone, isopropanol, isoparaffins, acetone, and butanol.

[0022] As a preferred embodiment, the diluent is acetone.

[0023] As a preferred embodiment, the lubricating agent is selected from one or a combination of silicone lubricants, aluminate lubricants, acrylate lubricants, and alcohol ester lubricants.

[0024] As a preferred embodiment, the lubricating agent is a silicone lubricant, the silicone lubricant is an alkyl siloxane, and the alkyl siloxane is selected from one of octyltriethoxysilane coupling agent, dodecyltrimethoxysilane coupling agent, and hexadecyltrimethoxysilane coupling agent.

[0025] A second aspect of the present invention provides a method for preparing a low contact thermal resistance thermal conductive silicone cloth, comprising the following steps:

[0026] (1) vacuum drying the inorganic powder and then naturally cooling it to room temperature;

[0027] (2) adding modified polysiloxane to the dried inorganic powder and the lubricating agent, mixing them evenly, adding a diluent, stirring evenly, and degassing to obtain a mixed rubber material;

[0028] (3) Apply the mixed adhesive to the base film, use a coating scraper to spread it evenly, dry it in a drying oven, cut it, and rewind it into a roll.

[0029] As a preferred embodiment, the vacuum drying temperature in step 1 is 170-200° C., and the drying time is 3-5 hours.

[0030] As a preferred embodiment, the degassing pressure in step 2 is -1 to 1 mPa, and the degassing time is 20 to 30 minutes.

[0031] As a preferred embodiment, the drying tunnel temperature in step 3 is 150-180° C., the drying tunnel length is 10-15 m, and the drying tunnel speed is 1-5 m / min.

[0032] As a preferred embodiment, the coating thickness in step 3 is 0.01-0.2 mm.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The low contact thermal resistance thermal conductive silicone cloth of the present invention is prepared by the thermal conductive powder prepared by the interaction of aluminum oxide of different shapes and particle sizes. The thermal conductive powder has low contact thermal resistance and high thermal conductivity coefficient. A high thermal conductivity efficiency can be achieved by using a low amount of thermal conductive powder.

[0035] (2) The low contact thermal resistance thermal conductive silicone cloth of the present invention adopts a coating processing technology, has low viscosity before molding, high filler mixing uniformity, is easy to process, and the surface flatness, thickness tolerance and product uniformity of the produced product are good.

[0036] (3) The low contact thermal resistance thermal conductive silicone cloth of the present invention has high reliability, insulation, softness and elasticity, low contact thermal resistance, and high thermal conductivity, and can be widely used in switching power supplies, communication equipment, computers, flat-screen TVs, mobile devices, video equipment, network products, household appliances and other fields. DETAILED DESCRIPTION

[0037] Example 1

[0038] A low-contact thermal resistance thermal conductive silicone cloth is prepared from the following raw materials in parts by weight: 15 parts of modified polysiloxane, 160 parts of inorganic powder, 0.3 parts of lubricating agent, and 7 parts of diluent.

[0039] The modified polysiloxane is vinyl-modified polysiloxane with a vinyl content of 0.18 wt % and a viscosity of 2500 mPa·s at 25° C. It was purchased from Shenzhen Jipeng Silicone Fluoride Materials Co., Ltd. with the brand name JP-01V-2500.

[0040] The inorganic powder is a combination of alumina and boron nitride; the alumina is a combination of spherical alumina with a particle size of 10 μm (Sichuan Ya'an Baitu New Materials, Bak-10), spherical alumina with a particle size of 3 μm (China Aluminum New Materials, ASF-3), and ellipsoidal alumina with a particle size of 0.5 μm (Sichuan Ya'an Baitu New Materials, SHA-10); the particle size of the boron nitride is 5 μm (Sichuan Ya'an Baitu New Materials, PBN-5); the weight ratio of spherical alumina with a particle size of 10 μm, spherical alumina with a particle size of 3 μm, ellipsoidal alumina with a particle size of 0.5 μm and boron nitride is 90:40:20:10.

[0041] The diluent is acetone. The lubricating auxiliary agent is octyltriethoxysilane coupling agent.

[0042] A method for preparing a low-contact thermal resistance thermally conductive silicone cloth comprises the following steps:

[0043] (1) vacuum drying the inorganic powder and then naturally cooling it to room temperature;

[0044] (2) adding modified polysiloxane to the dried inorganic powder and the lubricating agent, mixing them evenly, adding a diluent, stirring evenly, and degassing to obtain a mixed rubber material;

[0045] (3) Apply the mixed adhesive to the base film, use a coating scraper to spread it evenly, dry it in a drying oven, cut it, and rewind it into a roll.

[0046] The vacuum drying temperature in step 1 is 180° C. and the drying time is 4 h.

[0047] The degassing pressure in step 2 is -1 mPa, and the degassing time is 30 min.

[0048] The drying tunnel temperature in step 3 is 160° C., the drying tunnel length is 12 m, and the drying tunnel speed is 5 m / min. The coating thickness in step 3 is 0.03 mm. The base film is a PI film.

[0049] Example 2

[0050] A low-contact thermal resistance thermal conductive silicone cloth is prepared from the following raw materials in parts by weight: 16 parts of modified polysiloxane, 170 parts of inorganic powder, 0.4 parts of a lubricating agent, and 10 parts of a diluent.

[0051] The modified polysiloxane is vinyl-modified polysiloxane with a vinyl content of 0.28 wt % and a viscosity of 1500 mPa·s at 25° C. It was purchased from Shenzhen Jipeng Silicon Fluorine Materials Co., Ltd. with the brand name JP-01V-1500.

[0052] The inorganic powder is a combination of alumina and boron nitride; the alumina is a combination of spherical alumina with a particle size of 10 μm (Sichuan Ya'an Baitu New Materials, Bak-10), spherical alumina with a particle size of 3 μm (Sichuan Ya'an Baitu New Materials, Bak-3), and ellipsoidal alumina with a particle size of 0.5 μm (Sichuan Ya'an Baitu New Materials, Bak-S05); the particle size of the boron nitride is 10 μm (Sichuan Ya'an Baitu New Materials, PBN-10); the weight ratio of spherical alumina with a particle size of 10 μm, spherical alumina with a particle size of 3 μm, ellipsoidal alumina with a particle size of 0.5 μm and boron nitride is 100:40:20:10.

[0053] The diluent is acetone. The lubricating auxiliary agent is dodecyltrimethoxysilane coupling agent.

[0054] A method for preparing a low-contact thermal resistance thermally conductive silicone cloth comprises the following steps:

[0055] (1) vacuum drying the inorganic powder and then naturally cooling it to room temperature;

[0056] (2) adding modified polysiloxane to the dried inorganic powder and the lubricating agent, mixing them evenly, adding a diluent, stirring evenly, and degassing to obtain a mixed rubber material;

[0057] (3) Apply the mixed adhesive to the base film, use a coating scraper to spread it evenly, dry it in a drying oven, cut it, and rewind it into a roll.

[0058] The vacuum drying temperature in step 1 is 180° C. and the drying time is 4 h.

[0059] The degassing pressure in step 2 is -1 mPa, and the degassing time is 30 min.

[0060] The drying tunnel temperature in step 3 is 170°C, the drying tunnel length is 12m, and the drying tunnel speed is 4m / min. The coating thickness in step 3 is 0.04mm. The base film is a PI film.

[0061] Comparative Example 1

[0062] A low-contact thermal resistance thermal conductive silicone cloth is prepared by preparing raw materials comprising, by weight, 15 parts of modified polysiloxane, 150 parts of inorganic powder, 0.3 parts of a lubricating agent, and 5 parts of a diluent.

[0063] The modified polysiloxane is vinyl-modified polysiloxane with a vinyl content of 0.32 wt % and a viscosity of 1000 mPa·s at 25° C. It was purchased from Shenzhen Jipeng Silicone Fluoride Materials Co., Ltd. with the brand name JP-01V-1000.

[0064] The inorganic powder is a combination of alumina and boron nitride; the alumina is a combination of spherical alumina with a particle size of 10 μm (Sichuan Ya'an Baitu New Materials, Bak-10), spherical alumina with a particle size of 3 μm (Sichuan Ya'an Baitu New Materials, Bak-3), and ellipsoidal alumina with a particle size of 0.5 μm (Sichuan Ya'an Baitu New Materials, Bak-05), and the particle size of the boron nitride is 5 μm (Sichuan Ya'an Baitu New Materials, PBN-5); the weight ratio of spherical alumina with a particle size of 10 μm, spherical alumina with a particle size of 3 μm, ellipsoidal alumina with a particle size of 0.5 μm and boron nitride is 80:40:20:10.

[0065] The diluent is acetone. The lubricating auxiliary agent is hexadecyltrimethoxysilane coupling agent.

[0066] A method for preparing a low-contact thermal resistance thermally conductive silicone cloth comprises the following steps:

[0067] (1) vacuum drying the inorganic powder and then naturally cooling it to room temperature;

[0068] (2) adding modified polysiloxane to the dried inorganic powder and the lubricating agent, mixing them evenly, adding a diluent, stirring evenly, and degassing to obtain a mixed rubber material;

[0069] (3) Apply the mixed adhesive to the base film, use a coating scraper to spread it evenly, dry it in a drying oven, cut it, and rewind it into a roll.

[0070] The vacuum drying temperature in step 1 is 180° C. and the drying time is 4 h.

[0071] The degassing pressure in step 2 is -1 mPa, and the degassing time is 30 min.

[0072] The drying tunnel temperature in step 3 is 160° C., the drying tunnel length is 12 m, and the drying tunnel speed is 5 m / min. The coating thickness in step 3 is 0.07 mm. The base film is a PI film.

[0073] Comparative Example 2: A low contact thermal resistance thermal conductive silicone cloth, the raw materials for its preparation include, in parts by weight: 13 parts of modified polysiloxane, 180 parts of inorganic powder, 0.3 parts of lubricating agent, and 2 parts of diluent.

[0074] The modified polysiloxane is vinyl-modified polysiloxane with a vinyl content of 0.17 wt % and a viscosity of 3000 mPa·s at 25° C. It was purchased from Shenzhen Jipeng Silicone Fluoride Materials Co., Ltd. with the brand name JP-01V-3000.

[0075] The inorganic powder is a combination of alumina; the alumina is a combination of spherical alumina with a particle size of 10 μm (Sichuan Ya'an Baitu New Materials, SHA-10), spherical alumina with a particle size of 3 μm (Sichuan Ya'an Baitu New Materials, Bak-3), and ellipsoidal alumina with a particle size of 0.5 μm (Sichuan Ya'an Baitu New Materials, Bak-05), and the weight ratio of spherical alumina with a particle size of 10 μm, spherical alumina with a particle size of 3 μm, and ellipsoidal alumina with a particle size of 0.5 μm is 110:50:20.

[0076] The diluent is isododecane. The lubricating auxiliary agent is stearic acid.

[0077] A method for preparing a low-contact thermal resistance thermally conductive silicone cloth comprises the following steps:

[0078] (1) vacuum drying the inorganic powder and then naturally cooling it to room temperature;

[0079] (2) adding modified polysiloxane to the dried inorganic powder and the lubricating agent, mixing them evenly, adding a diluent, stirring evenly, and degassing to obtain a mixed rubber material;

[0080] (3) After the calendering process, the upper structure uses a release film, and the lower structure uses a PI film, which is dried in a drying tunnel, cut, and rewound into a roll.

[0081] The vacuum drying temperature in step 1 is 180° C. and the drying time is 4 h.

[0082] The degassing pressure in step 2 is -1 mPa, and the degassing time is 30 min.

[0083] The drying tunnel temperature in step 3 is 120° C., the drying tunnel length is 12 m, the drying tunnel speed is 1 m / min, and the calendering thickness in step 3 is 0.15 mm.

[0084] Performance Testing

[0085] 1. Thickness: The thickness of the high thermal conductive insulation sheets prepared in Examples 1-3 was tested with reference to ASTM D374.

[0086] 2. Contact thermal resistance: The contact thermal resistance of the high thermal conductive insulation sheets prepared in Examples 1-3 was tested with reference to ASTM 5470.

[0087] 3. Thermal conductivity: The thermal conductivity of the high thermal conductivity insulating sheets prepared in Examples 1-3 was tested with reference to ISO 22007-2.

[0088] 4. Breakdown voltage: The breakdown voltage of the high thermal conductive insulation sheets prepared in Examples 1-3 was tested with reference to ASTM D149.

[0089] The test results are shown in Table 1.

[0090] Table 1

Claims

1. A low contact thermal resistance thermal conductive silicone cloth, characterized in that: The raw materials for preparation include, by weight: 15-50 parts of modified polysiloxane, 120-550 parts of inorganic powder, 0.1-0.5 parts of lubricating auxiliary agent, and 0.2-45 parts of diluent.

2. The low contact thermal resistance thermal conductive silicone cloth according to claim 1, characterized in that: The modified polysiloxane is selected from one or a combination of double bond modified polysiloxane and hydrogenated modified polysiloxane.

3. The low contact thermal resistance thermal conductive silicone cloth according to claim 2, characterized in that: The modified polysiloxane has a viscosity of 30-550000 mPa·s at 25°C.

4. The low contact thermal resistance thermal conductive silicone cloth according to claim 1, characterized in that: The inorganic powder is selected from one or a combination of metal oxides, metal nitrides, non-metal oxides, non-metal carbides, and non-metal nitrides.

5. The low contact thermal resistance thermal conductive silicone cloth according to claim 4, characterized in that: The particle size of the metal oxide is 0.05-90 μm, and the particle size of the non-metal nitride is 3-15 μm.

6. The low contact thermal resistance thermal conductive silicone cloth according to claim 4, characterized in that: The inorganic powder is a combination of metal oxide and non-metal nitride, and the weight ratio of the metal oxide to the non-metal nitride is (145-165):

10.

7. The low contact thermal resistance thermal conductive silicone cloth according to claim 4, characterized in that: The metal oxide is selected from aluminum oxide, zinc oxide, magnesium oxide or a combination thereof.

8. The low contact thermal resistance thermal conductive silicone cloth according to claim 4, characterized in that: The diluent is selected from one or a combination of n-hexane, methanol, n-butane, toluene, xylene, cyclohexanone, isopropanol, isoparaffins, acetone, and butanol.

9. The low contact thermal resistance thermal conductive silicone cloth according to claim 4, characterized in that: The lubricating agent is selected from one or a combination of siloxane lubricants, aluminate lubricants, acrylate lubricants, and alcohol ester lubricants.

10. A method for preparing the low contact thermal resistance thermal conductive silicone cloth according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) vacuum drying the inorganic powder and then naturally cooling it to room temperature; (2) adding modified polysiloxane to the dried inorganic powder and the lubricating agent, mixing them evenly, adding a diluent, stirring evenly, and degassing to obtain a mixed rubber material; (3) Apply the mixed rubber material to the base film, use a coating scraper to spread it evenly, dry it in a drying oven, and cut it into pieces. Cut, rewind once into a roll, and you're done.

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