阅读说明：本技术 一种导热橡胶用高导热粉体的制备方法 (Preparation method of high-thermal-conductivity powder for heat-conducting rubber ) 是由 李光华 其他发明人请求不公开姓名 于 2020-04-14 设计创作，主要内容包括：本发明涉及橡胶产品制备领域,具体关于一种导热橡胶用高导热粉体的制备方法；其组分包括：钝化铝粉、碳纤维交联膨胀石墨粉、陶瓷粉、萤石粉末,偶联剂、硬酯酸锌和硅酸铝镁粉末；本发明所使用的钝化铝粉相比无机氧化物具有更加优异的导热比,而且经过钝化处理以后的铝粉具备良好的绝缘性能,材料的安全性有保障；而且偶联剂表面改性后材料提高了与橡胶材料的相容性,不会对材料的机械性能产生负面影响；本发明的高导热粉体具有添加量少,制备简单,导热效果好的优点,使用的材料来源易得,成本低廉,具有非常好的应用价值。(The invention relates to the field of rubber product preparation, in particular to a preparation method of high heat conduction powder for heat conduction rubber; the components of the composition comprise: passivated aluminum powder, carbon fiber cross-linked expanded graphite powder, ceramic powder, fluorite powder, coupling agent, zinc stearate and aluminum magnesium silicate powder; compared with inorganic oxides, the passivated aluminum powder used by the invention has more excellent heat conductivity, and the passivated aluminum powder has good insulating property after passivation treatment, so that the safety of the material is guaranteed; the material after the surface modification of the coupling agent improves the compatibility with the rubber material, and does not have negative influence on the mechanical property of the material; the high-thermal-conductivity powder has the advantages of small addition amount, simple preparation and good thermal conductivity effect, and the used material has easily available sources and low cost, and has very good application value.)

1. A preparation method of high heat conduction powder for heat conduction rubber comprises the following specific scheme:

according to the parts by mass, the high heat conduction powder for the heat conduction rubber comprises the following components: 14-27 parts of passivated aluminum powder, 38-52 parts of carbon fiber cross-linked expanded graphite powder, 3-7 parts of ceramic powder, 2-8 parts of fluorite powder, 0.1-0.8 part of coupling agent, 0.5-4 parts of zinc stearate and 5-12 parts of aluminum magnesium silicate powder;

the preparation method comprises the following specific scheme: adding aluminum powder into hot water at the temperature of 80-100 ℃, carrying out heat preservation reaction for 30-90min, taking out the aluminum powder, drying in a drying box, heating to 150 ℃ and 200 ℃, treating for 1-3h, cooling to room temperature, dispersing the aluminum powder in isopropanol, adding a coupling agent and zinc stearate, carrying out boiling reflux for 30-60min, adding carbon fiber crosslinked expanded graphite powder into a reaction system, carrying out rapid stirring for 30-60min, filtering, drying, and uniformly mixing with the rest materials to complete the preparation of the high heat-conducting powder for the heat-conducting rubber;

the preparation method of the carbon fiber crosslinked expanded graphite powder comprises the following steps:

according to the mass portion, adding 1.2-3.6 portions of surfactant into 220 portions of 0.5-0.8mol/L hydrochloric acid, uniformly mixing, adding 8.4-14.8 portions of expanded graphite powder into the solution, adding 3.2-6.8 portions of potassium persulfate under the condition of stirring, controlling the temperature to be 0-5 ℃, adding 6.3-12.8 portions of pyrrole monomer into the solution within 30-60min, continuing to react for 20-30h under the condition of room temperature after the addition is finished, filtering, washing and drying after the reaction is finished, placing into a tubular furnace, controlling the temperature to be increased to 700-900 ℃ under the nitrogen atmosphere, carrying out constant temperature carbonization reaction for 120-180min, and then cooling to the room temperature to obtain the carbon fiber crosslinking expanded graphite powder.

2. The method for preparing high thermal conductive powder for thermal conductive rubber according to claim 1, wherein the method comprises the following steps: the coupling agent is 3- (methacryloyloxy) propyl trimethoxy silane or aniline methyl triethoxy silane.

3. The method for preparing high thermal conductive powder for thermal conductive rubber according to claim 1, wherein the method comprises the following steps: the average grain diameter of the ceramic powder is 10-20 μm.

4. The method for preparing high thermal conductive powder for thermal conductive rubber according to claim 1, wherein the method comprises the following steps: the specific surface area of the aluminum powder is 0.5-4.5m²A/g spherical aluminum powder.

5. The method for preparing high thermal conductive powder for thermal conductive rubber according to claim 1, wherein the method comprises the following steps: the surfactant is sodium propyl naphthalene sulfonate or sodium octadecyl sulfate or coco glucoside.

Technical Field

The invention relates to the field of rubber product preparation, in particular to a preparation method of high thermal conductivity powder for thermal conductive rubber.

Background

At present, the heat conductivity of a rubber product is poor, heat generated under a dynamic working condition is accumulated in the rubber product to form local high temperature, and heat transferred from the outside in the using process cannot be quickly and effectively dissipated through rubber, so that the rubber product is accelerated to age, and the performance is reduced; how to improve the heat-conducting property of the natural rubber becomes a problem to be solved urgently.

CN110655698A provides a high thermal conductivity compounded rubber, comprising the following steps: step 1: taking ammonia gas as working gas, and carrying out plasma treatment on the carbon fiber to obtain modified carbon fiber; step 2: modifying the nano alumina by using ionic liquid to obtain ionic liquid modified nano alumina; and step 3: dispersing modified carbon fibers and nano-alumina modified by ionic liquid in a normal hexane solution, simultaneously adding rubber crude rubber into the normal hexane solution, mixing the 2 solutions after ultrasonic dispersion, and continuing ultrasonic dispersion; and 4, step 4: stirring the mixed solution in water bath to remove the solvent, adding the curing agent after the solution has constant weight, and stirring at room temperature; and 5: and pouring the polymer solution into a mold, and curing at 150 ℃ under a vacuum condition to obtain the high-thermal-conductivity composite rubber. The rubber roller prepared by coating the high-thermal-conductivity composite rubber outside the metal core material has good thermal conductivity and mechanical property, and can remarkably prolong the service life of the rubber roller.

CN104403329A discloses a heat-conducting silicone rubber, which is composed of the following raw materials in parts by weight: 3-5 parts of aluminum powder, 12-17 parts of graphene, 2-3 parts of ceramic powder, 1-2 parts of lithium carbonate, 0.4-1 part of ammonium metavanadate, 0.3-1 part of ascorbic acid, 10-13 parts of polybutylene terephthalate, 2-3 parts of calcium fluoride, 1-2 parts of 1, 2-dimethylimidazole, 2-4 parts of chlorinated paraffin, 0.5-1 part of potassium citrate, 0.5-1 part of dipropylene glycol, 1-2 parts of promoter CA, 3-4 parts of rare earth assistant, 100 parts of methyl vinyl phenyl silicone rubber, 108 parts of 1, 1-di-tert-butyl peroxycyclohexane 1-2 parts, the aluminum powder, the graphene, the ceramic powder and the like are added into the rubber, so that the heat-conducting property of the rubber can be obviously improved, the aging of the rubber caused by high temperature and slow heat conduction is slowed down, the service life of a rubber product is prolonged, and the application range of the silicon rubber is expanded.

CN101885918A discloses a heat-conducting silicone rubber, which comprises the following components in parts by weight: 22-25 parts of methyl vinyl organopolysiloxane with 0.03 percent of vinyl mole fraction; 4-5 parts of methyl vinyl organopolysiloxane with 0.05 percent of vinyl mole fraction; 18-20 parts of methyl silicone oil with the polymerization degree of 1000 CS; 28-75 parts of Al₂O₃(ii) a 0.9-1 part of a coupling agent; 0.36 to 0.4 portion of zinc stearate. The heat-conducting silicon rubber has the advantages of high heat conductivity, heat resistance and low compressibility, the heat conductivity coefficient of the heat-conducting silicon rubber is more than 3, and the invention improves the operability of the roller and the physical performance of demoulding. The articles produced by the present invention are permanently non-deformable and have very good stability during storage. The heat-conducting silicon rubber can be applied to heat-conducting materials or heat-radiating materials in automobiles, electric and electronic equipment which need enough heat resistance, heat conductivity and rubber elasticity.

The invention and the prior art prepare the heat-conducting rubber composite material by filling the high heat-conducting filler, and the method has simple processing technology and lower production cost. The heat conductive filler commonly used at present can be classified into metals, oxides, nitrides, carbon compounds and the like according to chemical components. The heat conduction mechanism of the materials is that the heat conduction filler is overlapped in the matrix to form a heat conduction network chain, so that the heat conduction performance of the composite material is enhanced. Therefore, the improvement of the heat conductivity of the rubber composite requires the addition of a large amount of heat conductive filler and the increase of the particle size of the filler, which may cause great damage to the mechanical properties of the rubber composite. In addition, silicon carbide, boron nitride, aluminum nitride, carbon nano tubes, graphene and other fillers are often added, which is very helpful for improving the heat-conducting property of the material, but the fillers are very expensive, the adding amount of the silicon carbide, the boron nitride and the aluminum nitride is 10-50%, the price is more than 300 yuan/kg, wherein the adding amount of the graphene and the carbon nano tubes is 10-50%, and the unit price is more than 2000 yuan/kg; this would undoubtedly increase the cost of the thermally conductive rubber composite, limiting the applications of the material.

Disclosure of Invention

In order to solve the problems, the invention provides a preparation method of high thermal conductivity powder for thermal conductive rubber.

A preparation method of high heat conduction powder for heat conduction rubber comprises the following specific scheme:

according to the parts by mass, the high heat conduction powder for the heat conduction rubber comprises the following components: 14-27 parts of passivated aluminum powder, 38-52 parts of carbon fiber cross-linked expanded graphite powder, 3-7 parts of ceramic powder, 2-8 parts of fluorite powder, 0.1-0.8 part of coupling agent, 0.5-4 parts of zinc stearate and 5-12 parts of aluminum magnesium silicate powder;

the preparation method comprises the following specific scheme: adding aluminum powder into hot water at the temperature of 80-100 ℃, carrying out heat preservation reaction for 30-90min, taking out the aluminum powder, drying in a drying box, heating to 150 ℃ and 200 ℃, treating for 1-3h, cooling to room temperature, dispersing the aluminum powder in isopropanol, adding a coupling agent and zinc stearate, carrying out boiling reflux for 30-60min, adding carbon fiber crosslinked expanded graphite powder into a reaction system, carrying out rapid stirring for 30-60min, filtering, drying, and uniformly mixing with the rest materials to complete the preparation of the high heat-conducting powder for the heat-conducting rubber.

The coupling agent is 3- (methacryloyloxy) propyl trimethoxy silane or aniline methyl triethoxy silane.

The average grain diameter of the ceramic powder is 10-20 μm.

The specific surface area of the aluminum powder is 0.5-4.5m²A/g spherical aluminum powder.

The preparation method of the carbon fiber crosslinked expanded graphite powder comprises the following steps:

according to the mass portion, adding 1.2-3.6 portions of surfactant into 220 portions of 0.5-0.8mol/L hydrochloric acid, uniformly mixing, adding 8.4-14.8 portions of expanded graphite powder into the solution, adding 3.2-6.8 portions of potassium persulfate under the condition of stirring, controlling the temperature to be 0-5 ℃, adding 6.3-12.8 portions of pyrrole monomer into the solution within 30-60min, continuing to react for 20-30h under the condition of room temperature after the addition is finished, filtering, washing and drying after the reaction is finished, placing into a tubular furnace, controlling the temperature to be increased to 700-900 ℃ under the nitrogen atmosphere, carrying out constant temperature carbonization reaction for 120-180min, and then cooling to the room temperature to obtain the carbon fiber crosslinking expanded graphite powder.

The surfactant is sodium propyl naphthalene sulfonate or sodium octadecyl sulfate or coco glucoside.

According to the preparation method of the high-thermal-conductivity powder for the heat-conducting rubber, the high-thermal-conductivity powder prepared by the method takes the carbon fiber crosslinked expanded graphite powder as a main raw material, the material is prepared by crosslinking the expanded graphite powder and the carbon fiber material, and a heat-conducting network chain is more easily formed in a matrix in a lap joint manner in the use process, so that the thermal conductivity of the composite material is effectively improved; in addition, compared with inorganic oxides, the passivated aluminum powder used by the invention has more excellent heat conductivity, and the passivated aluminum powder has good insulating property after passivation treatment, so that the safety of the material is guaranteed; the material after the surface modification of the coupling agent improves the compatibility with the rubber material, and does not have negative influence on the mechanical property of the material; the high-thermal-conductivity powder has the advantages of small addition amount, simple preparation and good thermal conductivity effect, and the used material has easily available sources and low cost, and has very good application value.

Detailed Description

The invention is further illustrated by the following specific examples:

the tensile strength and the tear strength of the rubber composite material prepared by the experiment are tested by GB/T528-2009; the heat conductivity test adopts DRL-III type heat flow method heat conductivity coefficient tester developed by Hunan Tan Xiang instruments Co., Ltd to test the heat conductivity coefficient of the sample, the thickness of the sample is 2mm, the diameter is 30mm, and the heat conductivity coefficient of the sample is obtained by testing at 50 ℃; each sample was measured three times and then averaged to give the final result.