Definition and characteristics of silicone material:
Silica gel is a highly active adsorption material, which is an amorphous substance. It contains polysiloxane, silicone oil, white carbon black (silicon dioxide), coupling agent and filler, etc. The main component is silicon dioxide, and its chemical The molecular formula is mSiO2·nH2O. It is insoluble in water and any solvent, non-toxic and tasteless, chemically stable, and does not react with any substances except strong alkali and hydrofluoric acid.
Various types of silica gel form different microporous structures due to different manufacturing methods. The chemical composition and physical structure of silica gel determine that it has many characteristics that are difficult to replace by other similar materials: high adsorption performance, good thermal stability, stable chemical properties, and high mechanical strength.
The raw rubber of silica gel before vulcanization has a linear molecular structure, while the cured rubber after vulcanization is a three-dimensional elastic body in the form of a network. Compounds such as Si-C bonds contained in silica gel are collectively referred to as organosilicon compounds.
The process flow of silica gel from raw rubber to compound rubber molding:
- During the mixing process, due to the low intermolecular cohesion of the raw silicone rubber, the silica filler with high reinforcement and high temperature resistance has become the most important compounding agent for silicone rubber. When selecting other compounding agents, it is necessary to consider the high temperature resistance. Requirements, that is, under the application conditions of silicone rubber, they must not be volatilized, decomposed, carbonized or discolored, etc. In order to maintain the heat resistance of silicone raw rubber and reduce the breakage of silicon bonds by acid and alkali attack, it is necessary to prevent foreign substances during mixing. Acids and alkalis are brought in, and the acidic substances produced by the decomposition of peroxide vulcanizing agents must be removed in time.
- Put the kneaded raw rubber and other ingredients into the vacuum kneader for cooking. The temperature is not high at the beginning. During the stirring process, the temperature rises slowly through friction and reaches 155-160 degrees. Just another half an hour.
- Put the boiled glue into the open mill to smooth it and roll it into a roll. Just be careful not to get dirty, and the number of rollings only needs 2-3 circles.
- After grinding, it needs to be cooled for about 3-4 hours, and then the glue is filtered through a screen to filter out some solid materials in the glue.
Silicone can be classified according to various characteristics:
- According to the composition, it can be divided into: one-component and two-component silica gel.
- According to the vulcanization temperature, it can be divided into: high temperature vulcanization and room temperature vulcanization silica gel.
- According to the form of the product, it can be divided into: liquid and solid silica gel.
- According to the vulcanization reaction, it can be divided into: condensation reaction type, platinum addition reaction type and peroxide curing type.
- According to the main chain structure, it can be divided into: pure silica gel and modified silica gel.
- According to product characteristics, it can be divided into: high and low temperature resistant type, antistatic type, oil and solvent resistant type, conductive type, foam sponge type, high strength tear resistance type, flame retardant and fireproof type, low compression deformation type, etc.
Modified silica gel is the modification of organic polymers. By blending organic polymers with silica gel, the molecular structure and state are changed, so as to improve the corresponding characteristics of silica gel materials and meet the specific needs of market customers.