Some products can be directly used after the molding process, and some products also need to undergo secondary vulcanization (also called secondary sulfur). In fact, we look like a good product from the naked eye after molding, can also be used normally, why also secondary vulcanization?
First of all, to be sure, not all need silica gel secondary vulcanization silicone rubber products, only depending on the formulation of raw materials, some of them are a molding can directly, but some special materials such as fluorine rubber products, some of the EPDM is the need for secondary vulcanization silicone rubber products, that's because the first of these materials in a sulfide, The peroxides in the polymer reaction will decompose, produce some low molecular compounds (such as benzene, benzoic acid, etc.), these low molecular compounds mixed in rubber will reduce the mechanical properties of silicone rubber, reduced life, but also toxic. This is very unfavorable for silicone kitchen utensils, so silicon rubber products J manufacturers commonly use secondary vulcanization to decompose and volatilize the low molecular compounds.
Second, at the end of a vulcanization, silica gel molecules may not be fully cross-linked (vulcanization is not sufficient), silicone rubber secondary vulcanization can make its vulcanization more fully, more uniform, so as to improve the mechanical properties and durability of rubber.
Third, the secondary vulcanization of silica gel, such as a large number of EPD silicone rubber products used in cars after secondary vulcanization can remove odor, improve the comfort of car occupants.
Fourth, silica gel products manufacturers wholesale in order to reduce costs, improve productivity, often shorten the first silica gel vulcanization time, and then in the extension of the second vulcanization time, to ensure that the product is fully vulcanized at the same time, but also to improve their competitiveness.
