Introduction to Silicone Insulating Paints-Part 3

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In last article, we have introduced two specific subcategories of silicone insulating paints. Today we will introduce some other important subcategories silicone insulating paints as well.

Glass Cloth and Tube Varnish Paint

Temperature-resistance H-grade electrical devices and engines need varieties of matching electrical isolation materials. Glass cloth and tube varnish paint is the softest methyl phenyl silicone resin in silicone paint film. Among them, glass fiber paint wires, glass fiber cloth and glass fiber tube and the glass paint cloth and glass cloth tube which are varnished by organic silicone varnish paints will have enough adhesion, thermal elasticity, abrasion resistance and scratch resistance. They are widely used in the wires and cables near automotive engines, the protection of humidity resistance and isolation of wires and the high-temperature components of radars, dry transformer and some devices. After they are heated in high temperature for a long time, they will gradually lose elasticity. This silicone paint requires both of softness from silicone rubber and flame resistance from resins. Usual electrical devices and household appliance’s varnish paint is generally solvent varnish paint and applies multiple varnish method; for dry transformers, they usually apply non-solvent organic silicone varnish paint.

Glass Cloth Varnish Paint for Laminates

Organic silicone glass cloth laminate is widely used as the isolation of slot wedges of H-grade electrical devices, wiring boards, tablet boards, isolation boards, radar cable cover, transformer tube, high-frequency and wave guide engineering’s microwave blocking boards. It could be also used for some other heat-resistance isolation materials.

To produce glass cloth laminates mainly use low R-Si ratio’s methyl phenyl siloxane as the adhesive.

It is due to the concentration of silicone paint, curbing agent’s amount, coating amount of silicone paint, pre-drying degree and some other factors will have large influence on the mature laminate’s property and appearance, therefore they are needed to be adjusted carefully. There are two types of main silicone paints which are used to produce glass cloth laminates- condensation and additional types. By using additional silicone paints, they could be shaped in a lower pressure; when using condensation silicone paints, the solidification is not easy to be perfect and is more convenient for high-pressure shaping due to there will produce some water and other micro molecular matters. Also, the produced products should be processed by some further thermal procedures to improve the mechanical and solvent resistance.

Low Temperature or Room Temperature Solidification Organic Silicone Paint

The usual pure organic silicone varnish paint usually requires the heating for a long time to get solidification. It is due to the high solidification temperature, its application scope has been restricted. The long time burning also breaches the Si-C key and oxides the organic functional groups. This brings difficulty to the applications of varnish paints. It is in order to lower the solidification temperature of organic silicone varnish paints, many countries successfully produces low-temperature dry paints.

The methods to produce it are:

1.      To use organic silicone resins that have small R/Si ratio and high methyl amount,  only this could allow to make its low-temperature and dry properties effective. However, this also reduce the heat resistance an elasticity of paints;

2.      To choose one type of curing agent, to make Si-OH key to be condensate in low temperature, or to make the inner circle to react open-loop polymerization to allow it to be dry in shorter period. This catalyst will not influence any electrical property and heat resistance.

The most important catalysts include leads, irons and cobalt’s soluble salts, amines and quaternary alkaloids.

At present, room temperature solidification organic silicone’s development trend is to use silica nitrogen resins or silica nitrogen compounds to solidificate the organic silicone resins.

Insulating Covering Magnetic Paint-Organic Silicone Silicon Steel Sheet Isolation Paint

It is used to different types of electrical devices, cable wires of electrical devices, the protection layer for the surfaces of cables and shells of sealing to improve humidity resistance, electrical isolations, chemical erosion resistance and some other properties. Silicon steel sheet paint covering paint has the advantages like heat resistance, oil resistance, isolation and others. It could be divided into varnish or surface magnetic paint.

Organic Silicon Electrical Device Component Coating Material

One part is the resistor or capacitor coating material. It has the advantages like humidity resistance, heat resistance, isolations, heat-resistance alternation, and high mechanical properties of paint layer, good adhesion, abrasion resistance and stable insulating resistor.

Organic silicone insulating paint has excellent heat resistance and electrical isolation, but its solvent resistance, mechanical property and adhesion are worse, these could be generally improved by adding some epoxy resins or heat-resistance polyesters. However, if the design artifacts are proper, then it will not influence the heat resistance.

Organic silicone modified polyester or epoxy resin paint could be used for F-grade insulating paint. It has good corona resistance, humidity resistance, adhesion to the bottom, chemical resistance and mechanical strength.

Another part is the semiconductor component use organic silicon high-temperature insulating protective paint. It has good dielectric property, high purity and has some restrictions on harmful metal’s content. It also has good adhesion, thermal stability, humidity resistance and protection for semiconductors. It is useful in high-temperature and high-compress places.

The third part is for printed circuits board use organic silicon insulating protective paints. It has good toughness, dielectric property, weather resistance, UV resistance, dust pollution resistance, humidity resistance, could be dried in room temperature, good light penetration and is effective in the insulating protection of printed circuits boards, integrated circuits and solar cells.

Summary

From the recent two blog articles we could see that there are many subcategories of insulating paints which could be used in different industries. This is why they are now welcome in both of domestic and international markets. Also, as one of the most important applications of organic silicone resins, it is also being studied by many researchers who make lots of efforts in that field. Now, there are also more and more new types of insulating paint products coming to the market for sales as well.