Introduction to Organic Silicon Coatings - Part 2

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In last article, we have introduced two types of organic silicon coatings and today we will continue to introduce more types of them.

Abrasion Resistance Coating

It is in order to protect the surface colors of soft metals, glasses, plastics and rubbers, and to allow them to have abrasion resistance and easy to clean, there usually requires one layer of abrasion resistance coating. The excellent materials used to make abrasion resistance surface layer are usually to use trifunctional units or tetrafunctional and trifunctional units as main raw materials, and to use hydrolysis or condensation to make low R/Si ratio methyl silicone resin prepolymer. It will be coated on the base material and then be further crosslinked to make new resins. This coating layer has good adhesion to base materials. After solidification, its appearance is like glass thus it is also called glass resins. It is the highly crosslinked organic silicone resin that developed by American company Owens ILLinois in the end of 1960s.

It is due to the R:Si ratio in glass resin is smaller (equal to 1 or a little bigger than 1), then its functionality is very big and it spatial resistance is small, thus its C2H5O- is easy to be hydrolyzed, and the HO- is very easy to be condensate to body structure. Therefore, this resin has the property of fast solidification in low temperature and it has good film forming ability. If to add a small amount of drying agent, the silicone resin could have solidification to film in low temperature in few minutes; even if not to add drying agent, it will also form solidification film in few days in room temperature or in few hours when being baked.

The common way to use glass resin could take varnish coating method, to coat it on organic glass or similar material. One pound of glass resin could be used to coat 300 square feet layer with a thickness of 0.126m. This could be applied in the wind shield and window of airplanes, the back window of cars, the glasses of trains and some safe windows. By coating them with glass resin, these base materials’ abrasion resistance, chemical corrosion resistance and light penetration will be improved. The only requirement on the coated base materials is to have enough ruler stability in their corresponding glass resin maturation temperature.

The main feature of organic silicone glass resin is hard and transparent. When its form is made, the slime film has good isolation, and it also has properties like abrasion resistance, heat resistance, aging resistance, radiation resistance, non-crispy in low temperature, solvent resistance, humidity resistance, non-poisoned and strong light penetration. There will be no gas releasing during usage even in some extreme conditions. It could also improve base materials’ properties like humidity resistance, aging resistance, radiation resistance and anti-shocking. Abrasion resistance coating could be widely used in all kinds of plastics and rubber products, it is mainly used as the transparent abrasion resistance protection layer for glass, organic glass, silicone resin, silicone rubber, wind shields on cars and airplanes, metallic plastics, poke cards and some high-grade posters. Also, it is since the glass resin coating layer’s fractration rate is lower than all types of transparent plastics. Therefore, it could be used to improve optical properties of products.

Adhesion Resistance Demoulding Coating

It is since the coming out of organic silicon high polymer, people find it has many special properties especially being used as the demoulding agent. The products like silicone resins, silicone oil and silicone rubbers are all able to be used as demoulding agents. To choose the proper type of products as demoulding agent in different time and space depends on the economy, product life and the difficulty in usage. The adhesion resistance and demoulding property of silicone resin are similar with silicone oil and silicone oil emulsion’s and it could be used as the adhesion resistance and demoulding coating. The main differences are: silicone resin use reactivity, crosslinking and film formability to make a half-permanent slim film on the base materials or forming molds after solidification, therefore it is better than silicone oil, silicone oil emulsion and silicone rubber demoulding agent. It could be used over hundreds of times without recoating. By painting, spraying and varnishing, to coat the coating solvent on the needed place on the surface of materials, it is after the violation of solvent and the heating and solidification, we could get the tough resin film. The silicone resin coating which is used for demoulding is usually the thin solvent that mixes silicone resin that has low R/Si ratio with some other mixed solvents. There is usually some silicone oil to be added into it to prevent the silicone resin layer from being thermal breaching. It is in order to get the best demoulding effects and to confirm the film’s adhesion is tight, it is a must to use sandblasting to clean and degrease the surface of metal molds.

Silicone resin demoulding coating has advantages like:

1.      It has good heat resistance and will be hard to violate or decompose on molds in high temperature. It also has good thermal oxidation resistance and chemical stability;

2.      The intermolecular forces are small and it has low surface tensile strength. It is insoluble in most macromolecular materials and also hard to stick to them;

3.      It is not poisoned and it does not have smells, thus it could be used in food and medical industries;

4.      To extend the product life of metals, molds and cavities;

5.      It could reduce the amount of used materials and human cost. It is safe and convenient;

6.      It could maintain the molds and cavities clean, and reduce the amount of harmful smokes.

Summary

Another two important organic silicon coating have been introduced! There are still some other types that carry special properties will be used in some specific industries. In the next article, we will continue to introduce these types of products!