Silicone rubber is a straight chain of high molecular weight polysiloxane, molecular weight is generally more than 150,000, its structure is similar to silicone oil. According to the organic groups linked to silicon atoms, silicone rubber has dimethyl silicone rubber, methyl vinyl silicone rubber, methyl phenyl silicone rubber, fluorine silicone rubber, nitrile silicone rubber, ethyl silicone rubber and many other varieties.
  According to its vulcanization method, silicone rubber can be divided into high temperature vulcanization (hot vulcanization) silicone rubber and room temperature vulcanization (including low temperature vulcanization) silicone rubber two categories. No matter which type of silicone rubber, there is no exothermic phenomenon when vulcanized. High temperature vulcanized silicone rubber is a high molecular weight polysiloxane (molecular weight is generally 400,000 to 800,000), and room temperature vulcanized silicone rubber is generally low molecular weight (30,000 to 60,000).
 Room temperature vulcanized silicone rubber (RTV) has one or two functional groups at each end of the molecular chain (and sometimes in the middle), and under certain conditions (moisture in the air or appropriate catalysts), these functional groups can react to form a high-molecular weight cross-linked structure.
  According to its vulcanization mechanism, it can be divided into condensation type and addition type.
  According to its packaging can be divided into two components and single components of two types.
 peculiarity：
Single component room temperature vulcanized silicone rubber:
RTV-1 adhesive is used as an adhesive together with polysulfide rubber, polyurethane rubber, etc., but RTV-1 adhesive has the following characteristics:
1. All the components are mixed and packed in a container. As long as the rubber material is extruded, it can be vulcanized into an elastomer when it meets the moisture in the air.
2. The temperature has little effect on the viscosity of the adhesive, and the same operation method can be used regardless of cold winter or hot summer;
3. According to needs, can be made into viscosity flow type products used as coatings, but also can be made into non-flowing thixotropic products, used as vertical gap filling seal;
4. Maintain rubber elasticity in a wide temperature range (-60 ° C to 300 ° C);
5.Excellent adhesion to most substrates, if the use of primer, better adhesion;
6. Humidity has little effect on vulcanization hardness;
7. Excellent electrical performance;
8. No heat absorption and no heat release during vulcanization;
9. Excellent resilience when compressed or stretched;
10. In addition to acetic acid type and ketone oxime type, no corrosion, vulcanizate is chemically inert;
11. Excellent heat, cold and weather resistance;
12. Can be made into transparent products, can also be made into various colors.
 Two-component room temperature vulcanized silicone rubber:
RTV-2 adhesive has the following advantages over RTV-1 adhesive and other two-component systems:
1. It is convenient to use, without heating and pressurizing equipment, just mix the basic rubber material with the catalyst, and it can be vulcanized into an elastomer, and there is no heat absorption or heat release problem. Polyester resin and epoxy resin can be used under similar conditions, but there are disadvantages of heat release when curing.
2. According to the processing and application needs, it can be made from low viscosity oil to high consistency paste or putty adhesive products, and vulcanized adhesives with different properties can be obtained by changing the catalyst variety, dosage and vulcanization conditions.
3. The vulcanization process of RTV-1 rubber is slowly vulcanized from the outside to the inside by contacting the moisture in the air, while RTV-2 rubber is vulcanized inside and outside at the same time.
4.RTV-1 adhesive has good adhesion to most substrates, while RTV-2 adhesive has good release property to most substrates and small shrinkage rate, so it is widely used for making soft molds. When the adhesive is added to the binder or the substrate surface is first treated with a primer, RTV-2 adhesive can also obtain good adhesion.
5.RTV-2 rubber has the heat resistance, cold resistance, weather resistance, arc resistance and electrical insulation of mixed silicone rubber and RTV-1 rubber, and maintains rubber characteristics in a wide temperature range (-60 ° C to 300 ° C), and has good vibration absorption.