Silicone Rubber Sheet 1

by Dongrubber on September 17, 2006 · 0 comments

1. Brief Introduction of Silicone Rubber

Silicone rubber is elastomer with polysiloxane as main chains, while the polysiloxane are repeatedly connected by Si-O (silicon-oxygen) chains.

Silicone rubber is widely used in automotive, electrical and electronic applications, office machinery three areas, besides it has a large number of usages in construction, medical, food industry, etc., it belongs to special category synthetic rubber, but the people have used it as a general rubber.

Silicone rubber is different from natural rubber and other synthetic rubber, people generally don’t sell them in the form of raw rubber, such as in the form of masterbatch for sale in the European and American countries, also have sales in mixing rubber method, Japanese manufacturers supply all in the form of Ready-use goods. This is because, in the rubber products factory, silicone rubber products have general varieties and small batch production, and with silica as a reinforcing agent it needs special equipment for smelting process (to avoid mixed with ordinary carbon black, stabilizer and other impurities and reduce the physical performance and appearance quality of finished product). Users are more restricted in the distribution conditions.

Silicone rubber has more variety; it also has different classification methods.

(1) The classification according to their chemical components. They are divided into dimethyl silicone rubber, methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber sheeting, fluorine silicon rubber, nitrile silicone rubber, the phenyl silicone rubber, boron silicone rubber and RTV silicone rubber.

(2) The classification according to the shape and crosslinking mechanism. Silicone rubber is sorted out according to its shape and crosslinking mechanism, can have a variety of grades, can be roughly divided into linear siloxane polymer polymerization degree of 5000 ~ 10000 (colloidal) as the main ingredients of mixed type and degree of polymerization of 100 ~ 2000 line siloxane polymer (oil) as the main ingredients of liquid state.

2. The characteristics of the silicone rubber

Silicone rubber molecule main chain containing silica (Si – O) special structure link, it determines that it has the following features.

(1) High and low temperature resistance. Silicone rubber is a kind of heat resistant rubber. Among various kinds of rubber, it has the most wide working temperature range (100 ~ 350 ℃). Appropriate cooperated with vinyl silicone rubber, for example, after thousands of hours or after 300 ℃ thousands of hours or 250 ℃ hundreds of hours hot air ageing, it stays the same rubber shape feature; Low glass transition temperature of phenyl silicone rubber as -140 ℃, its vulcanizates at -70~100℃ temperatures remain resilient. Silicone rubber used for rocket nozzle wall thermal coating endures momentary thousands of degrees high temperature.

(2) Excellent oxygen aging, ozone aging, light aging resistance and weathering performance. Silicone rubber vulcanizates in the free state in outdoor exposure after a few years will still has no significant change in its performance.

(3) Excellent electric insulation performance. Electric insulation performance of the silicone rubber vulcanizates is slightly affected with damp or under the influence of water temperature, combustion generated silica are still insulators, this ensures the electric equipment can continue working, until the maintenance.

(4) Physiological inertia. Silicone rubber is tasteless, non-toxic, no bad influence to the human body.

(5) Special surface performance. Silicone rubber is hydrophobic, not sticky to many material, has an isolation effect.

(6) High permeability. Silicone rubber permeability is tens to hundreds times larger than ordinary rubber. And for different gases (O2, N2, CO2, etc.) the permeability difference is big.

(7) Special silicone rubber has oil resistant, radiation resistant, resistant to combustion performance.

(8) Good mildew resistance. Silicone rubber products after long-term storage, its water absorption is less than 0.015%, without breeding effect for a variety of algae and mildew, therefore, it will not mildew.

(9) The main drawback of silicone rubber sheet is when at room temperature, its analysis of the tensile strength, tear strength and abrasion resistance, etc., are much lower than the natural rubber and other synthetic rubber, poor in acid, alkaline resistance, and the price is more expensive.

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