Silicone building sealant is mainly composed of base rubber, filler, crosslinker, catalyst and other additives. The base rubber is the basic material of the sealant and determines the performance of the sealant. The base rubber is 107 room temperature vulcanized silicone rubber, the chemical structure is hydroxyl terminated polydimethylsiloxane, the filler is some inorganic powder, such as white carbon black, calcium carbonate, heavy calcium, etc., the role of the filler is to provide strength, hardness, flow Variable performance, etc. The cross-linking agent and the catalyst are curing systems of the sealant, and the sealant is changed from a liquid state to an elastomer by reacting the base rubber with the cross-linking agent and the catalyst and the moisture in the air.
The production process of the sealant is a process in which the components constituting the sealant are uniformly mixed. The usual production method is to mix the base material and the filler by a kneading machine, and if necessary, grind with a grinder, and then use a planetary machine to uniformly mix the crosslinking agent, the catalyst and other auxiliary agents under vacuum.
Compared with other types of sealant, silicone building sealant has good elasticity, high temperature resistance and low temperature flexibility. It has good weather resistance, ozone resistance and UV resistance, and has a long service life, but silicone. The cost is relatively high, usually more expensive than other types of sealant, the strength is especially poor tear resistance, there is information that the water resistance is worse than polyurethane sealant, oil resistance is not as good as polysulfide sealant.
Building sealants can be classified by different methods. The usual classification method is to classify by chemical composition. According to the chemical composition of the base rubber used in the sealant, the sealant can be classified into polysulfide, polyurethane, silicone, neoprene, butyl rubber, acrylic rubber and the like. At present, the most used amount on the market is silicone, polyurethane and polysulfide.