Alkylation modification and application of silicone oil
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Unmodified silicone oil mostly refers to dimethyl silicone oil. Because of its flexible Si-O-Si main chain and methyl side chain, it has the characteristics of low surface tension and flexibility. It is used in daily chemicals, textiles, machinery, petrochemicals. and other industries are widely used. However, with the development of science and technology, the application of dimethicone in some industries is gradually limited. In addition to the problem of overcapacity, it is urgent to increase the R&D investment and output of high-performance products to meet the development needs of downstream applications.
Alkylation modification of silicone oil refers to increasing the side chain length from 1 carbon of methyl to 12-16 carbons. The increase of carbon chain length will also change its physical properties, thus giving alkylated silicone oil better Compatibility, lubricity and hydrophobicity, so it has better application performance than dimethicone in many industries.
1. Lubricating oil
With the increase of carbon chain length, the molecular volume of alkyl silicone oil increases, and the molecular chains are easily entangled to form a thicker lubricating film to improve lubricity. In addition, alkyl silicone oil can also be used for the lubrication of soft metals (such as aluminum, zinc, steel, etc.) and rubber and plastics (especially when used with steel, aluminum, etc.).
2. Defoamer
When dimethyl silicone oil is used for defoaming of coating inks, due to its incompatibility, shrinkage craters and silicon spots are prone to occur. Thanks to the good affinity of long-chain alkyl silicone oil for organic materials, the defoamer formulated from it can avoid this problem. In addition, in order to reduce the number of rinsing and save water resources, the washing powder no longer pursues excessively high foam volume. The solid defoamer with cetyl silicone oil as the active agent can significantly reduce the foaming performance of washing powder products, and its market prospect broad.
3. Release agent
When dimethyl silicone oil is used as a mold release agent, it is easy to remain after mold release, which affects secondary printing, while alkyl silicone oil has no residue after use and does not affect the printing and painting of products, so it is also called "drying silicone oil" by industry insiders. . The double modification of the silicone oil with alkyl and phenyl can improve the high temperature resistance of the silicone oil, and the obtained alkylaryl silicone oil has a good application in the aluminum alloy die-casting and demolding industry.
4. Personal Care
Compared with dimethyl silicone oil, alkyl silicone oil has good compatibility with higher alcohols, liquid paraffin, etc., and is easier to emulsify. When used in cosmetics, it not only maintains the safety and smooth touch of organopolysiloxane, but also grafts. The long alkyl chain can improve the affinity with the skin and make the cosmetic spread better.
The alkylation modification of silicone oil is mainly based on the hydrosilylation reaction, which is mostly obtained by the addition of α-olefin and hydrogen-containing silicone oil. The source of raw materials for this reaction is relatively easy, and the experimental conditions are mild. It is an industrial silicone oil alkyl modification. main program.