TYPES AND CHARACTERISTICS OF ORGANOSILICON DEMOULDING AGENTS (I)


1. Classification of organosilicon release agents


1.1 Classification by product composition and form


There are many kinds of release agents based on silicone. According to the characteristics of product form, material composition and use form, it can be classified as follows:


(1) Organic silane and its solution


The base material of release agent is organic chlorosilane or organic alkoxysilane. For example, methyl chlorosilane, methyl ethoxysilane, phenyl chlorosilane, phenyl ethoxysilane and other organosilicon compounds, or the above organosilicon dissolved in organic solvents in the organic silane solution, coated on the surface of the die base material, can form an anti-bonding working film. The application of organochlorosilane as release agent has some limitations. Among them, organochlorosilane can absorb water in air and release hydrogen chloride from the process of hydrolysis and film formation. It is only suitable for corrosion-resistant die substrates such as glass and ceramics.


(2) Silicone oil, its solution and ointment


The base material of release agent is inert linear polymer silicone polymer such as methyl silicone oil, methyl phenyl silicone oil and various modified silicone oil. The commonly used silicone oil release agent is a silicone oil solution composed of silicone oil as the main component, and then added with toluene, gasoline and other organic solvents.


Semi-solid paste demoulding agent can be prepared by mixing silicone oil with solid components such as silica, diatomite and mica powder.


_Silicone Rubber and Its Solution


Liquid silicone rubber can be directly used as demoulding agent, but more applications are to prepare silicone rubber solution by adding organic solvent to silicone rubber, and then to coat on the surface of the die with cross-linking agent, catalyst and other additives to form vulcanized silicone rubber working film.


_Silicone resin and its solution


The base materials of release agent are methyl silicone resin and methyl phenyl silicone resin, which can be crosslinked and cured. The silicone resin is usually dissolved in organic solvents such as ethanol, toluene and gasoline to form silicone resin solution. The release agent is coated on the surface of the die by spraying or dipping process, and then the silicone resin is solidified into a working film by heating.


Silicone emulsion


The emulsion is made from silicone oil or silicone resin and added emulsifier and water. The water emulsion coated on the mold surface is formed after the moisture evaporates.


_Silicone aerosol


Silicone oil as the main component, with freon, butane and other propellants, mixed packaging in sealed containers. When the release agent is applied, the main component of the release agent is carried by the ejector and sprayed on the surface of the die. The ejector evaporates rapidly, and the residue forms the working film of the release agent.


_Other Types


In addition, there are also direct applications of silicone rubber to manufacture elastic molds. The silicone rubber mold itself not only has good heat resistance, but also has excellent properties of anti-bonding and easy demoulding. It is especially suitable for moulding demoulding of complex shaped products.


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