Manufacturing and Examples of Pure Silicone Resins

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There are a few types of pure silicone resins; each of them may have different manufacturing procedures and characteristics.

Before its solidification, silicone resin is prepolymerized silicone resin. It could achieve crosslinking solidification through condensation, reaction of organic peroxide and hydrosilylation reaction. Condensate prepolymerized silicone resin molecules mainly contain Si-OH, Si-OR and Si-H functional groups and they will be condensate under catalyst or being heated and finally crosslinked to be the solid products.

The common catalysts include Pb, Zn, Sn, Co, Fe, Ce and some other metallic naphthenates or some other salts. Methyl silicone resin, phenyl silicone resin and methyl phenyl silicone resins are all condensate silicone resins.

Methyl Silicone Resin

Methyl silicone resin is the product which is produced by using methyltrichlorosilane, methyltrialkoxysilane or methyltriacyloxysilane as the base and the ethanol as the solvent to make the hydrolysis condensation reaction. The silicone resins after solidification are highly crosslinked. It has high transparency, big hardness, good wear resistance and look like glass. That is why it is called glass resin. It is widely used in plastics like organic glass and paper coating material.

Different structural unit has different ratio, which constructs methyl silicone resins which have different properties. For example, there could be soft, soluble and fusible silicone resin or hard, insoluble and infusible silicone resin.

The property of the final processed product of silicone resin is determined by the number of contained functional groups and ratios of different organic functional groups. Therefore, it is important to decide to choose which monomer and how to make their ratio firstly for manufacturing silicone resin. The types of silicone monomers and the consumption amounts are determined by the using object and the detailed requirements. The general rule is: when R/Si is smaller, the manufactured silicone resin is way easier to be hardened in lower temperature; when the R/Si is bigger, the silicone resin will need longer time to be heated in higher temperature but the thermal elasticity is way better than the former one.

Some type of methyl silicone resin has some unique advantages:

The manufacturing device has larger volume usability. The production efficiency is high and the procedures like washing and filtering could be ignored. The corresponding post-processing is simple.

It is during the reaction, no organic solvent will be used therefore there will be no phenyl and other harmful matters in resin products; the hydrolysis process will not release corrosive hydrochloric acid which will definitely reduce the corrosion to the device.

The PH is easy to be controlled and which means it is good to be applied in industrial mass production to get high-quality and stable methyl silicone resins.

Phenyl Silicone Resin

Phenyl silicone resin is manufactured via hydrolysis condensation of PhSiX3 (X=Cl, OMe or OEt) or co-hydrolysis condensation of PhSiX3 and Ph2SiX2. If to use the general hydrolysis condensation method, the phenyl silicone resin which is made from PhSiCl3 will have too large thermal elasticity which makes it has no actual value. However, it is due to PhSiCl3 will be hydrolyzed under certain conditions, and then be reacted to get PhSiO1.5. Thus, it has very good summarized property. It has been applied in reality. When PhSiCl3 is hydrolyzed, it firstly produces low-mol-quantity polymer which contain hydroxyl, then it has condensation between molecules or inside the molecule and to form benzene ladder polysiloxane which has high mol quantity. It is different from silicone resin, it is in the form of loop shape and it could be soluble in benzene, tetrahydrofuran and dichloromethane and other organic solvents, and it could flow to be the transparent and tough slim film. However, it could not be melt. It has good humidity and heat resistance, and its thermal aging resistance in the steam is as good as in the air. Its tensile strength is double as the general silicone resin which reaches 27.4-41.2MPa. It also has excellent electrical properties.

Methyl Phenyl Silicone Resin

Methyl phenyl silicone resin contains both of methyl Si-O structural unit and phenyl Si-O structural unit. It could be formed by certain ratio of MeSiO1.5, Me2SiO, MePhSiO, PhSiO1.5 and Ph2SiO.

Among all organic silicone resins, methyl silicone resin has the lowest carbon percentage, but it has very good heating resistance. The resin has high crosslinking degree, big hardness and small thermal elasticity. It also has good waterproof and humidity resistance thus it is used as some surface pigments and adhesive. However, the pure methyl silicone resin has bad compatibility with organics and pigments thus it has been strict with the application industries. Methyl phenyl silicone resin could be regarded as to add phenyl Si-O chain into methyl silicone resin to improve its thermal elasticity, compatibility with organic resins and pigments and the adhesion to different base materials. Its properties are generally better than methyl silicone resins. It is now widely used as high-temperature resistance varnish, high-temperature resistance pigments, high-temperature resistance adhesive and some other materials.

MQ Silicone Resin

MQ silicone resin is one of the silicone resins, it is hydrolysis condensate by R3SiO1/2 and SiQ4/2. It has unique properties with bright future. It has excellent heating resistance, low-temperature resistance, film formability, softness, waterproof and adhesion. It is mainly used as the filler of pressure sensitive adhesive. At the same time, it is also extent to be MDQ or MTQ structural silicone resin by adding some other organic functional group into MQ silicone resin.

Summary

As the info shown above, different silicone resin could be divided by the functional groups it contain. Also, the ratio of different functional groups could also influence the properties of silicon resins even though they are categorized as the same subcategory of silicone resins. Some silicone resins could also been turned to another subcategory by being added some other functional group chain. These fast and reliable adjusting methods are so important and cheap to get the most accurate materials required by the market.

All in all, the silicone resin has a bright future in both of commercial and industrial value on the global market.