High temperature vulcanized silicone rubber is a high molecular weight (generally molecular weight of 400,000 to 800,000) polyorganosiloxane (ie, raw rubber). It is reinforced with fillers and various other additives. It uses organic peroxide as a vulcanizing agent and is molded under pressure. (Molded, extruded, calendered) or injection molded, and crosslinked into rubber at high temperature. This rubber is generally referred to as silicone rubber

The vulcanization of high-temperature vulcanized silicone rubber is generally divided into two stages. The first stage is to mix the silicone rubber, reinforcing agent, additive, vulcanizing agent and structure control agent, and then add the mixture in a metal mold. Pressure heating molding and vulcanization, the pressure is about 50 kg / cm2, the temperature is 120 to 130 ° C, and the time is 10 to 30 minutes. The second stage is to remove the silicone rubber from the mold and put it in an oven at 200 to Bake at 250 ° C for several hours to 24 hours. The rubber is further vulcanized and the organic peroxide is decomposed and volatilized.

The reinforcing filler of silicone rubber is various types of white carbon black, which can increase the strength of vulcanizate ten times. Adding various additives is mainly to reduce the cost of the rubber, improve the properties of the rubber, and give the vulcanizate various special properties such as flame retardancy and electrical conductivity. Crosslinking agents are various organic peroxides, such as benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, 2,5-di-tert-butylperoxyhexane, etc. .Structure control agent is added in order to avoid the compounded rubber being left for a long time, resulting in "structuring", which makes the rubber hard and hard and difficult to process and mature. As a structure control agent.

The side groups on the silicone rubber main chain may be methyl, ethyl, vinyl, phenyl, trifluoropropyl and the like. The most common is methyl, and other groups can be introduced to improve processability and other properties. Therefore, according to the different side groups and rubber formulations, silicone rubber can be obtained for various purposes. Generally, it can be divided into the following types: general type (including methyl and vinyl), high temperature and low temperature (including Phenyl, methyl, and vinyl), low compression set (containing methyl and vinyl), low shrinkage (devolatization), and solvent resistance (fluorosilicone rubber). Several important types of silicone rubber are described below.