Secondary vulcanization of silica gel industry
Jun 17, 2020
What is the secondary vulcanization in the production of silica gel products?
Secondary vulcanization, also known as post-vulcanization and disulfide, is a process in which silicone products continue to be vulcanized by heating without heat source after they reach a certain degree of vulcanization.Usually, the silica gel product will stop heating immediately after production, and the product will further deepen the vulcanization process under the action of waste heat or in the process of storage, or cross-linking phenomenon will continue to occur under the dynamic action.Further heating for secondary vulcanization is also a process.
What is the effect of secondary vulcanization?
The secondary vulcanization of silica gel products is to further improve the mechanical properties and deformation properties of silica gel products.This process is mainly used for some products with high seal performance requirements, such as silicone seals, seal gaskets, etc.
In the silicone products industry, for the quality of the silica gel products are divided into different levels, such as some miscellaneous pieces of silicone accessories such as routine just by moulding, and some exports or daily life supplies, such as silica gel products will be made in material selection and process aspects are quite different, so the single from the aspects of material, still far cannot meet the requirements of the quality of the product, and subsequent processing of production is also very important link.
Silicone product factories generally divide the finished products into ordinary silica gel, food-grade silica gel and medical-grade silica gel. The three kinds of silica gel products with different grades and classifications have different target groups and application scopes.Ordinary silica gel is generally used in industry, electronic industry or peripheral protection, while food-grade silica gel is used in our daily life, such as cake silica gel mold, ice cube mold and so on. In this way, food-grade silica gel is usually selected for production.
Common molding process is the high temperature of 180 degrees Celsius for moulding production, different material will remain in the different catalytic material, make the silicone products mixed materials of the corresponding compounds leads to certification testing pass, so often need to do test products can choose secondary plus sulfur for processing, in order to achieve certification testing standards, and the significance of secondary plus sulfur is the product of the transition sulfide compounds with sulfur, keep the products inside without any chemical hazards.
After the normal processing of vulcanized products, no matter what level of materials do not carry out the secondary sulfur treatment, it is basically impossible to pass the environmental protection certification. Only after the secondary sulfurization treatment, the products can pass the environmental protection certification, and there is no difference between the products, and they can be used normally.The main difference is that products that have not been treated with secondary vulcanization will produce chemical residues resulting in odor, yellowing, product toughness, decline in life and other phenomena.
