Preparation of Thermal Silicone Rubber for LED Beauty Light

[Source: "High - tech LED - Technology and Applications" November issue]

The thermal conductive silicone rubber for LED heat-resistant lamps was prepared by using zinc oxide, aluminum oxide, aluminum nitride and silicon carbide as heat-conductive fillers. The effects of the type and ratio of the thermally conductive filler on the thermal conductivity and mechanical properties of the silicone rubber were investigated. The results show that with the increase of the amount of thermal conductive filler, the thermal conductivity of silicone rubber also increases, but the mechanical properties and processing properties deteriorate. The particle size of aluminum nitride has little effect on thermal conductivity, but it is mechanical. The performance has a great influence. When the amount of 0.5um aluminum nitride is 150 parts, the heat-vulcanized silicone rubber has a Shore A hardness of 69 degrees, a tensile strength of 3.0Mpa, a tensile elongation of 160%, and a tear strength. It is 15.6 Kn/m and the thermal conductivity is 0.546 W/m·K.

With the development of industrial production and science and technology, traditional metal thermal conductive materials are limited in some fields. For example, in the field of electrical and electronic, due to the development of integration technology and micro-encapsulation technology, electronic components and electronic devices are becoming smaller and denser. The development of the direction leads to more heat in a limited volume; at this time, an insulating material with higher thermal conductivity is required to quickly dissipate the generated heat. The high thermal conductivity and thermal conductivity of high thermal conductivity silicone rubber materials meet the requirements of the above specific fields. The thermal conductivity silicone rubber used in industrial applications not only requires good thermal conductivity, but also needs good mechanical properties. Therefore, research on thermal silicon Rubber materials are of great significance.

In this paper, thermal conductive silicone rubber was prepared with gold thermal conductive fillers such as zinc oxide, aluminum oxide, aluminum nitride and silicon carbide. The effects of the type and ratio of thermal conductive filler on the thermal conductivity and mechanical properties of silicone rubber were studied. The research and development provides a certain reference.

I. Experiment

1.1 main raw materials and equipment

Polymethylvinylsiloxane (referred to as silicone rubber): 110-1S, 110-2S, molar mass 60×104~70×104g/mol, Jiangsu Hongda New Materials Co., Ltd.; Zinc Oxide: Particle Size 1um, Foshan Huaya Powder Material Co., Ltd.; Alumina: particle size 1.5um; Foshan Huaya Powder Material Co., Ltd.; Aluminum nitride: particle size 0.5um, 1.0um, 5.0um; Foshan Weikede Chemical Materials Co., Ltd. Company; silicon carbide: particle size 0.5um; Foshan Weikede Chemical Materials Co., Ltd.; hydroxy silicone oil 203 (hydroxyl content ≥8.0%): Wuxi Quanli Chemical Co., Ltd.; release agent: Hangzhou Grease Chemical Co., Ltd.; vulcanizing agent :YY-C-8B Zhen Mingli Group Co., Ltd.

Kneading machine: ZH-5, Foshan Jinyinhe Machinery Equipment Co., Ltd.; open mill: XK-160A, Shanghai Rubber Machinery Factory; flat vulcanizing machine (25 tons): subsidiary factory of Shanghai Shanshan Rubber & Plastic Machinery Industrial Co., Ltd.; material tensile machine : XL-250A, Guangzhou Experimental Instrument Factory; Hardness Tester: LX-A, Shanghai Liuling Instrument Factory; Thickness Gauge: Shanghai Liuling Instrument Factory; Thermal Conductivity Tester: DRP-II, Xiangtan Instrument and Meter Co., Ltd.

1.2 sample preparation

The raw rubber with the molecular weight of 60-700,000 and the mixed vinyl content of 0.135% is selected as the base rubber, and the different heat-conductive fillers are divided into 4 times and the raw rubber is finished in the kneading machine. At the same time, a structuring agent, a releasing agent, and the like are added, and kneading is carried out under heating and vacuum conditions, and then the sample is opened.

The sample of the rubber compound is placed on the roll of the open mill, the vulcanizing agent double 2, 5 is added, and the thin pass is made 3 to 5 times, and the film is taken out; and the vulcanized molding machine is vulcanized and formed. The sample was vulcanized at 175 ° C for 5 min. Stop 4H, cut pieces. The mechanical properties of the samples were measured. Two-stage vulcanization conditions: 200 ° C × 4H.

1.3 performance test

Tensile strength and elongation: Tested according to GB / T 5 2 8 - 2 0 0 9; Hardness: Tested according to GB / T531-2008; Thermal conductivity: Tested according to GB/T11205-2009.


       For more information, please refer to "High - tech LED - Technology and Applications" November issue

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