The ratio of methyl to phenyl groups in organic groups also has a great influence on silicone resin properties. The lower the phenyl content in the organic group, the softer the paint film will be and the faster the condensation will be. The higher the phenyl content, the harder the paint film will be and the more thermoplastic it will be. The phenyl content is between 20% and 60%, and the paint film has the best bending resistance and heat resistance. In addition, the introduction of phenyl groups can also improve the compatibility of silicone resin with other silicone resins and organic pigments, and can improve the adhesion of silicone resin to various substrates.
Therefore, when manufacturing silicone resins with different uses and properties, you must first consider which monomers to choose and determine their mixing ratio.


Silicone resin is a thermosetting plastic. One of its most outstanding properties is its excellent thermal oxidation stability. Its heat resistance is much better than ordinary organic resins. Silicone resin has a high thermal decomposition temperature, can be used for a long time at 200-250℃ without decomposing, and can withstand high temperatures of 350-500℃ in a short period of time. After adding heat-resistant filler, it can withstand higher temperatures. The heat resistance of modified silicone resin is worse than pure silicone resin, but better than organic resin, generally between silicone resin and corresponding organic resin.
Another outstanding feature of silicone is its excellent electrical insulation properties, which can be maintained over a wide temperature and frequency range. Generally, the electrical breakdown strength of silicone resin is 50kV/mm, the volume resistivity is 1013~1015Ω·cm, the dielectric constant is about 3, and the dielectric loss tangent value is about 10-3.


In addition, silicone resin also has excellent moisture resistance, water resistance, rust resistance, cold resistance, ozone resistance and weather resistance. It has good corrosion resistance to most water-containing chemical reagents such as dilute mineral acids, but has poor solvent resistance. In view of the above characteristics, silicone resin is mainly used as insulating paint (including varnish, enamel, color paint, impregnating paint, etc.) to impregnate H-class motors and transformer coils, and is used to impregnate glass cloth, glass cloth silk and asbestos cloth to make motors Bushings, electrical insulation windings, etc. Using silicone insulating paint to bond mica can produce large-area mica sheet insulation materials, which can be used as the main insulation of high-voltage motors. In addition, silicone resin can also be used as heat-resistant and weather-resistant anti-corrosion coatings, metal protective coatings, waterproof and moisture-proof coatings for construction projects, release agents, adhesives and secondary processing into silicone plastics for use in the electronics, electrical and defense industries. , as semiconductor packaging materials and insulation materials for electronic and electrical components.

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