Introduction to Single Component Silicone Rubber Adhesive and Sealant

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Single component silicone rubber sealant or adhesive is to mix rubber, filler and crosslinking agent together to be some ointment, and to seal it in metallic hose. This storage way could keep it for a long time. When using it, it could react with the small amount of water existed in air to form elastomers.

The manufacturing process of silicone sealant is generally the same with other common silicone rubber adhesives. It is to mix the silicone rubber with other agents or materials.

During the time of usage, it is to mix two components together. Generally, to add vulcanization system components into the mixed rubber components and then shake it averagely then it could be used.

Single component RTV silicone rubber sealant and adhesive has good properties, it could be stick to the surfaces of glasses, plastics and metals tightly. It could be applied to many sticks between metals and non-metallic materials and seals. It is mainly used as the sealing and adhesion materials which need cold and heat resistance, humidity resistance, electrical isolation and shocking resistance. It is simple to operate and convenient to use. It is widely applied and if we make some proper processing on the surface of the sticked material by using organic silicon agent, then it could nearly sticks to all kinds of materials. It also has excellent water resistance and chemical solvent resistance. For example, in electronical industries, it could be used for the sealing and coating of electrical devices, electronical parts and optical devices. In the aircraft manufacturing industries, it could be sued for the sealing and adhesion between windows and doors. In recent years, single component silicone adhesive applies fast in construction areas; it could be used to some parts’ sealing materials, waterproof materials and the adhesion materials. Also, it has important usages in mechanicals, automotive, ships and some surgeries aspects.

Single component silicone rubber adhesive and sealant no needs temporary materials, it is not only very convenient to use, but it could also avoid the wastes or mistakes made of double components sealant and adhesive’s temporary materials. It increases the reliability of usage. At the same time, this kind of silicone rubber sealant and adhesive has very good stability and adhesion. Therefore, it is since the 60s of 20^th century where it came out, the development of it increases rapidly. Now it already takes more than half of market shares of sealant markets.

RTV silicone rubber and HTV silicone rubber have similar thermal stability.

The solidification process of single component system could be divided into two steps: the first step is to use active straight chain organic siloxane to be the base materials and then to use the rest of hydrolysable functional groups to digest the water in the air to make hydrolysis condensation reaction to fulfill the solidification.

Different crosslinking agents have different influences on the properties of vulcanized sealants. The common used crosslinking agents have methyltrimethoxysilane, methyltriacetoxysilane and tetraethoxysilane.

The vulcanization speed of single component sealant is not only influenced by crosslinking agent, but also influenced by the humidity of the air and environmental temperature. Also, the rubber layer cannot be too thick which is usually thinner than 1cm, it must be noticed during usage. The vulcanization process relies on the water in the surrounding air. Therefore, vulcanization is from the surface to the deep inside. The thicker the rubber layer is, the slower the vulcanization speed is.

The vulcanization of sealant firstly starts with the surface that contacts with the air, and then there will produce a layer of rubber film. Then the water gas in air will vulcanize the inside gradually via the rubber film. The side products of reaction are dispersing continuously. The whole vulcanization enters more and more deep. As the thickening of vulcanized rubber film, the water gas is getting hard to get through and the molecules of reactive side products are harder to be dispersed; finally, the vulcanization speed gets slower. Therefore, if it is too thick, or even it has been placed for a long time, the inner side of silicone layer could not be vulcanized as well. Generally, the thick layer is less than 1cm. This is different from double components system, double components system could be vulcanized by both of the surface and the inside at the same time and it will not be affected of the thickness of rubber layer.

As for the manufacturing of single component silicone rubber adhesive and sealant, it is to add RTV silicone rubber raw rubber and filler and other additives to be mixed averagely in the device and then to remove the water inside it by reduce the compresses and increasing temperature. Also, to add crosslinking agent and catalyst in the environment that has no water and to mix them averagely. At this time, the hydroxyl of silicone rubber and the hydrolysable functional groups of crosslinking agents could make condensation reactions and releases some micro molecular matters. Finally it will produce the single component matured product which is the sealant intermediary which has the rest of hydrolysable functional groups. To package these matured products into the waterproof containers in some environment that has no water to supply the market. Sealants could be kept for a very long period in this condition of isolating any water. The containers are usually paper or plastic package tubes; it is 300ml volume and the length and radius are the same in international market.

Summary

In this article we have introduces single component silicone rubber adhesive and sealant in detail. It is easy to use and the manufacturing process is simple as well. This makes a lot of manufacturers and suppliers start to sell these and these products are also very welcomed in many different industries from different nations. Therefore, the future and market potential of this product is pretty bright and nice and now it is one of the largest selling products in the whole organic silicone products industry.