Common molding liquid silica gel is divided into a single component and two components, mostly translucent or high transparent liquid.The proportion of AB components of the two-component liquid silica gel is generally 1:1, 10:1, 9:1, etc.Molding liquid silicone rubber is a higher grade of silicone rubber varieties, compared with condensed liquid silicone rubber, vulcanization process does not produce byproducts, shrinkage, can deep vulcanization and other advantages, at high temperature sealing is also better than condensed silica gel.
Additive silicone rubber has a wide range of applications. Additive reactive vulcanized liquid silicone rubber is often used for perfusion sealing and other applications, playing the protective functions of moistureproof, heat resistance, insulation, shock absorption and so on.Gel-type silicone rubber is mainly used for encapsulation protection of micro-electronic components, encapsulation of sensors and distributors and other devices.
Basic chemical components of addition molding:
1. Organosilicon based polymer
Add molding liquid silica gel basic component silicone based polymer, mainly contains two or more than two silicone vinyl poly two organic siloxane.Usually a linear silicone polymer with a vinyl at both ends of the polymer chain, some in the middle of the polymer chain contains a small amount of silicon a vinyl chain.A typical base polymer used for Z is α, ω -divinylpolydimethylsiloxane, or simply vinyl silicone oil.
2. The crosslinking agent
Add molding liquid silica gel basic component crosslinking agent, is containing three or more than three silicon a hydrogen bond organosiloxane oligomer, that is, low viscosity methyl containing hydrogen silicone oil.
3. The catalyst
Although there are many kinds of catalysts that can trigger hydrosilylation reaction, the catalysts that can be used to add liquid silicone rubber are only the group ⅷ transition metal elements and their compounds or complexes, among which platinum catalysts have high catalytic efficiency Z.Using platinum catalyst directly, silicone rubber can be catalyzed at room temperature to complete hydrosilylation vulcanization reaction;Catalysts for medium temperature vulcanization can be prepared by adding appropriate inhibitors to platinum catalysts.
4. Fill the reinforcing material
The mechanical strength of silicone rubber obtained by crosslinking silicone based polymer and hydrogen containing silicone oil is not high. In order to improve the mechanical strength of silicone rubber, it is necessary to add reinforcing filler in silicone rubber system.Z commonly used reinforcing fillers are gas phase silica, precipitation silica, quartz powder, etc.To obtain colorless and transparent silicone rubber, it is necessary to use methyl vinyl MQ silicone resin as transparent reinforcing filler.
5. Other additives
Different additives are needed to adjust the process performance or service performance of silicone rubber.Mix glue color, need to use pigment or dye as colorant;In order to improve the heat resistance of silicone rubber, heat resistance additives need to be added;In order to improve the bonding properties of silicone rubber, adhesives and other auxiliary components should be introduced.
Through the detailed introduction of the above, add molding liquid silicone knowledge do you understand?If you want to know more about liquid silicone, please pay attention to us.
