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Liquid silicone rubber can be used for coating, dipping and pouring. For example, hydroxy-terminated polydimethylsiloxane with a viscosity of 0.07 ~ 50 Pa · sec / 25 ° C, using methyl vinyl bispyrrolidone silane as a chain extender, and using organic peroxides such as dibenzoyl peroxide 25-Dimethyl 5-di-tert-butylperoxyhexane is used as a vulcanizing agent. This kind of rubber has good fluidity and low viscosity. During the vulcanization process, a chain growth reaction occurs simultaneously, so a high molecular weight elastomer can be obtained. , With good physical and mechanical properties. The chain extender methylvinyl dipyrrolidone silane can be obtained by the reaction of pyrrolidone and methylvinyl dichlorosilane in the presence of triethylamine, the product is easily hydrolyzed, so it needs to be stored in a dry and closed container The group can react slowly with the terminal hydroxyl groups in the polydimethylsiloxane at room temperature, and its reaction speed increases with increasing temperature. In theory, this reaction can be continued until an infinite molecular weight is obtained. The vinyl group in methylvinylpyrrolidone silane can also be used as the activation point of the vulcanization reaction, which can promote the crosslinking of polydimethylsiloxane to form a high molecular weight elastomer. Since the pyrrolidone group and the hydroxyl group react very slowly at room temperature, the compound after adding the components has a long pot life. The viscosity of the compound is basically unchanged within 1 hour, but it still maintains good fluidity. Can be injected into tiny pores. The mixed rubber compound is vulcanized into an elastomer by heating at 150 ° C for 10 minutes.
1. Injection molding liquid silicone rubber: the full name is injection molding liquid silicone rubber, and the vulcanization equipment is an injection molding machine. The injection molding machine has a very simple process flow (no manual processes such as batching, rubber mixing, cutting, and trimming in the high-temperature glue process are required, only one worker can take the product), and the product accuracy is high (all manual procedures before molding) All are replaced by machines), high output (A / B glue is mixed and formed at a certain temperature for a few seconds), saving people, electricity, materials and other advantages, can produce all products produced by high temperature glue! Is the mainstream of the development of silicone rubber materials in the next few years.