The result of improving the performance of silicone rubber self-adhesive tape
First, the fatty acid metal salt (zinc stearate) with a molar fraction of methyl vinyl siloxane chain link of 0.15%, an average degree of polymerization of about 8,000 methyl ethyl quaternary cinnamon rubber at 100 C~ A paste containing 50% of the effective ingredients is prepared on a double-roll rubber mixer at 200 °C. Then the mole fraction of methyl vinyl siloxane segments is 0.15%, 70 parts of methyl vinyl cassia rubber with a degree of polymerization of about 8,000, and the mole fraction of methyl vinyl siloxane segments is 0.5%. 30 parts of methylvinyl cassia rubber raw rubber with a degree of about 8 000, mixed uniformly in a kneader, add 35 parts of Nihon Denki Kogyo Co., Ltd. acetylene carbon black, furnace carbon black (Japan Female, y Qiangong Xi o Xiyi Yu V 3 Yu Shao Co., Ltd. Commodities: 亇, y Qiangong, y Xi EC—600 JD) 5 copies and graphite powder (Co., Ltd. 1 and 4-,> One product: SBC7.彳——POG) 40 parts, mixed into rubber compound. Separate the rubber material on a two-roller
It is mixed with the above-mentioned preparation of 0.6 parts of fatty acid metal salt containing 50% sound material, and 0.8 parts of vulcanizing agent 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane to form Mixing silicone rubber. The mixed silicone rubber was vulcanized by hot pressing at 150 °C, 2.9X106 Pa for 10 min to prepare 1mm and 2 mm thick test pieces, and then vulcanized at 200 C for 4 hours to test the volume resistivity and physical properties of the pieces. For comparison, the fatty acid metal salt is not added, and other conditions are the same.
In order to prepare highly conductive mixed silicone rubber, the method of increasing the amount of carbon black is usually adopted, and the hardness of conductive silicone rubber after vulcanization is higher. For silicone rubber parts that require low hardness and high conductivity, two specific carbon blacks can be used in combination to reduce the amount of carbon black added to obtain high conductivity and low hardness silicone rubber. Two types of specific carbon blacks should meet the conditions: ① Carbon black made by acetylene pyrolysis; ② Carbon black made by non-acetylene pyrolysis, with toluene coloring light transmittance above 90%, and the specific surface area of carbon black A and carbon black B The difference should be above 1,000 mm2/g and below 1,500 m2/g.
The ratio of carbon black A to carbon black B can be calculated according to the conductivity and hardness of the final conductive silicone rubber between 20: 80 and 80: 20. The total compounding amount of A and B can be 5-25 parts based on 100 parts of raw silicone rubber.
