What's The Difference Between Silicone and Silicone Rubber?

 I. What is Silicone?

As some chemistry books call it, "silicone" should be a condensation of silicon dioxide, with the formula mSiO2·H2O. "silicone" is a kind of highly active adsorption material, belongs to the amorphous substance, insoluble in water and any solvent, non-toxic and tasteless, stable chemical properties, in addition to strong alkali, hydrofluoric acid does not react with any substance. And we often say that nasal augmentation and breast enhancement filled with silicone is this kind of silicone.

Inorganic silicone is a kind of highly active adsorption material, which is usually made by the reaction of sodium silicate and sulfuric acid, and a series of post-processing processes such as aging and acid bubble. Silicone is an amorphous substance, and its chemical formula is mSiO2. nH2O. Insoluble in water and any solvents, non-toxic and tasteless, stable chemical properties, except strong alkali, hydrofluoric acid does not react with any substance. Different types of silica gel form different microporous structures due to their different manufacturing methods.

The chemical composition and physical structure of silicone determine that it has many other similar materials that are difficult to replace the characteristics: high adsorption performance, good thermal stability, stable chemical properties, and high mechanical strength. Because of its chemical properties, it is used to make many kinds of silicone products, such as silicone seals, silicone sealing strips, silicone gaskets, and so on.

Silicone, according to the size of its pore size is divided into large pore silicone, coarse pore silicone, B-type silicone, and fine pore silicone. Due to the different pore structures, their adsorption properties have their characteristics. Coarse pore silicone has a higher adsorption capacity in the case of high relative humidity, fine pore silicone in the case of low relative humidity adsorption capacity is higher than coarse pore silicone, and B type silicone due to the pore structure between the coarse and fine pore, its adsorption capacity is also between the coarse and fine pore. Macroporous silicone is generally used as a catalyst carrier, matting agent, toothpaste abrasive, etc.

II. What is Silicone Rubber?

But in the molding industry, the "silicone" we refer to is usually not the silicone hydrate mentioned above. The silicone of the molding industry is usually said to be a kind of polysiloxane. Simply put, the "silicone" of the molding industry is a kind of synthetic rubber, which is called silicone rubber because it contains silicone atomic components, so it is referred to as "silicone".

There are many kinds of "silicone" in the molding industry and different uses. As for product performance, there is a big gap according to the different raw materials, but in general, this "silicone" (to be exact, silicone rubber) in the future shows a trend of replacing rubber. We often refer to "silicone" not simply referring to the condensation of silicon dioxide, nor the silicification of synthetic rubber above the mold industry. Instead, they call both products "silicone". At this time we divided "silicone" into organic silicone and inorganic silicone. Inorganic silicone is the hydrate of the first "silicone" we mentioned.

The silicon-containing synthetic rubber in the molding industry is called organic silicone because it contains hydrocarbon groups. In some places, "silicone rubber" will be defined as "between organic and inorganic matter," but more silicone rubber manufacturers still claim to be producing organic silicone.

III. The Classification of Silicone Rubber

Silicone rubber is one of the most widely used products in organic silicone products. After vulcanization, silicone rubber has excellent high and low-temperature resistance, weather resistance, hydrophobia, electrical insulation, physiological inertia, and so on.

Main properties and applications of silicone rubber products: according to its vulcanization temperature, silicone rubber can be divided into high-temperature (heating) vulcanization type and room-temperature vulcanization type two categories, high-temperature adhesive is mainly used for manufacturing all kinds of silicone rubber products, and room temperature adhesive is mainly used as adhesive, potting material or mold.

Room temperature vulcanized silicone rubber (RTV)

Room temperature vulcanized silicone rubber generally includes condensation type and forms two categories. The molded room temperature adhesive is a linear polysiloxane with vinyl as the base adhesive, with hydrosiloxane as the crosslinking agent, in the presence of a catalyst at room temperature to medium temperature crosslinking reaction becomes an elastomer. It has good heat resistance, hydrophobicity, and electrical insulation. At the same time, due to the introduction of the active end group, it has excellent physical and mechanical properties, especially in tensile strength, relative elongation and tear strength have been significantly improved. It is suitable for a variety of vulcanization methods, such as radiation vulcanization, peroxide vulcanization, and molding vulcanization, widely used in heat resistance, moisture-proof, electrical insulation, high-strength silicone rubber products, and other aspects.

Condensed RT-vulcanized silicone rubber is characterized by the condensation reaction between the silicone hydroxyl group and other active substances, and can be cross-linked to become an elastomer at room temperature. The product is divided into two forms single-component packaging and two-component packaging. Single-component RTV-1 adhesive is one of the main products of condensed liquid silicone rubber. It is usually prepared by basic polymer, crosslinking agent, catalyst, filler, and additive. The product is packaged in a sealed hose, extruded during use, and can be vulcanized into an elastomer after contact with air, which is extremely convenient to use. Vulcanized rubber can be used in the temperature range of (-60 ~ +200℃) for a long time, with excellent electrical insulation properties and chemical stability, water resistance, ozone resistance, climate aging resistance, a variety of metal and non-metallic materials have good adhesion. It is mainly used for coating various electronic components and electrical equipment. The sealing material plays the role of insulation, moisture-proof and shock-proof. As a surface protection material for semiconductor devices; It can also be used as a sealing interstitial material and elastic adhesive.