Introduction to Silicone Resin Part 2

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In last blog, we have introduced the basic info and the different methods of categorization of silicone resins. In this article, we are going to introduce more on the properties and applications of different types of silicone resins.

Basic Properties of Silicone Resins

It is due to the special chemical structures of silicone resins, they have some properties of organic resins and inorganic materials. The properties of the matured products which are made from silicone resins are determined by the ratio of organic parts and inorganic parts of the chemical structure of silicone resins which could be also interpreted as the value of R/Si. The generally useful or valuable silicone resins will have the R/Si value of its molecular components between 1.0 and 1.6. The general rule is that when the R/Si value is smaller, the got silicone resins could be easier to have solidification in lower temperature; if the R/Si value is bigger, the collected silicone resins are needed to be heated during 200~250 Celsius Degrees for a long time to get the final solidification. The corresponding film hardness will be weaker but the thermoelasticity will be better.

Besides these, the ratio of methyl groups and phenyl groups in the organic functional groups will also have a big influence on the properties of organic silicone resins. If the percentage of phenyl is lower, the produced film will be softer and faster to be condensate; if the proportion of phenyl is higher the film will be harder and will have good thermoelasticity. When the phenyl groups take 20% ~ 60% of the structure, the bending resistance and heat resistance of silicone resins will be the best. Otherwise, to lead phenyl into the silicone resins could improve the compatibility between them and other silicone organic silicone resins and organic inks; this will also improve the adhesion of silicone resins to many base materials.

Therefore, when we are going to manufacture silicone resins for different applications and of different properties, it is the first thing to consider that which monomers and ratios they should be.

Silicone resin is a thermosetting plastic; its most outstanding property is the excellent thermo oxidative stability. The heat resistance of it is way better than any other ordinary organic resins. Silicone resins have high thermal decomposition temperature and could be used under between 200 and 250 Celsius Degrees without being decomposed. It could also be resisted under between 350 and 500 Celsius Degrees for a short time. By filling some heating-resistance fillers the corresponding heat resistance of silicone resins will be better. The heating resistance of modified silicone resins may be weaker than pure silicone resins but better than organic resins, this is usually between silicone resins and corresponding organic resins.

Another good feature of silicone resins is the fantastic electrical isolation and it could be maintained in a wider temperature and frequency range. The general electric breakdown strength is about 50kV/mm.

What is more, silicone resins also have features like humid resistance, waterproof, antirust, cold resistance, odor resistance and weather resistance. It also has corrosion resistance to most chemical liquid which contain water like dilute mineral acids. However, the corrosion resistance is weak to solvents.

It is according to the properties mentioned above; the organic silicone resins could be electric isolated paints which include cleaning paints, ceramic paints, color paints and immersion paints which are used to immerse H-grade electrical machineries, transformer coils, glass-cloth-made tubes of machineries and electrical insulation winding. Besides these, silicone resins could also be used to anticorrosive paints which have heating resistance and weather resistance, metal protection paints, construction engineering paints which have waterproof and humid resistance.

Main Products of Silicone Resins

The main products of silicone resins are paints, adhesives and plastics for molding. Silicone resins could be also categorized by their applied temperatures. The first category is over 400 Celsius Degrees, the organic functional groups of silicone resins will be oxide under such a high temperature, produce volatile components and finally produce silicon dioxide. It could be reacted with other materials which have heating resistance to produce composite materials which have better heating resistance. The second type is less than 300 Celsius Degrees. Under this circumstance, silicone resins will maintain its chemical structure quo even if it is used for a long time. 300~400 Celsius Degrees is a tough range because the functional groups in silicone resins will be oxide but the temperature is too low to make further reactions. The third type is the environment which is under the room temperature. For this category, the wetting and hydrophobic capacities are the utmost important factors.

There are many types of organic silicone isolated paints. The electric machineries and electric devices need a variety of electric isolation materials and these are usually organic materials which are painted with isolation paints. Therefore, the technological level of electrical equipment is highly depending on the quality of isolation paints.

The general organic isolation paints could only be used for a long-term period under 130 Celsius Degrees, some organic resins who have better heating resistance could only be used in 150 Celsius Degrees while the application temperature of organic silicone isolation paints could be as high as 180~200 Celsius Degrees. In some cases, the temperature could even be 250~300 Celsius Degrees. The materials which are painted with organic silicone isolation paints could be regarded as H-grade electric isolation materials.

The weight, volume price and product life of electric machinery and electrical equipment is firstly determined by the properties of isolation paints. The better the heating resistance of electric isolation material is, the stronger the electrical isolation is. In the same conditions, the electrical equipment could be designed smaller and lighter with a longer product life. The organic silicon isolation material is the anti-high-temperature isolation material which has excellent properties. It could reduce 35% ~ 40% of the weight of electric machinery which has the same power, and it also reduces the needed consuming amount of bronze and silicon steel slices.

Summary

Silicone resins have been proved to perform excellently in many industries and this why they are urgently required by today’s industries.