Addition silicone rubber is easy to demould and has almost no active groups on its surface. Under normal circumstances, it can be easily demoulded without adding release agent.
The release agent of condensation silicone rubber is generally divided into internal release agent and external release agent.
The internal release agent was added to the uncured silicone rubber liquid. During curing, the release agent molecules migrate to the interface to form a surface release with poor adhesion. Generally, higher fatty acids and their metal salts, W/O silicone oil emulsion, liquid polyisobutylene, azo compounds, higher fatty alcohols, ester waxes, etc. You can choose. The advantage of internal release agent is easy to use, but the disadvantage is that it will affect the properties of vulcanized silicone rubber to some extent.
An external release agent is coated on the surface of the mold to form a film, thereby separating the mold from the cured silicone rubber. Generally, it can be divided into inorganic release agent and organic release agent. Inorganic release agents are very simple, such as talcum powder and clay. And can be applied to the interior of the mould. The advantage is cheap, but the disadvantage is dust pollution.
Organic release agents are mainly oily liquids, such as methyl silicone oil, vaseline, industrial butter, liquid polyethylene glycol and liquid paraffin. The film can be formed by coating on the surface of the mold. The advantage is good demoulding effect, but the disadvantage is that it may be dissolved in uncured silicone rubber solution, which needs to be confirmed by experiments first.
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