Introduction to Additional Liquid Silicone Rubber

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In last blog we have introduced about details of RTV silicone rubber, today we will introduce liquid silicone rubber which has closed relation with RTV silicone rubber.

What we called additional liquid silicone rubber is developed in 70^th of 20^th century which is considered one of the higher-quality silicone rubbers. It is an important development and application of speier’s hydrosilylation reaction in the vulcanization of silicone rubbers. Additional vulcanized silicone rubber is the chemical that to use the polymer which contains linear polysiloxane which has vinyl, to use the low polysiloxane which contains Si-H key as vulcanization crosslinking agent and to use catalyst in room temperature or medium temperature to make the additional reaction to form elastomer which has net structure.

Additional silicone rubber’s vulcanization is between RTV and HTV, its vulcanization could get better result between 40~120℃, thus it is called low-temperature vulcanized (LTV) silicone rubber as well. To choose the proper catalyst could allow it to be vulcanized in room temperature. The vulcanization time is mainly determined by temperatures. Therefore, to change temperature could adjust the vulcanization speed. Its raw rubber is in liquid form and it has good mobility before vulcanization and its convergence is over 1000 so it is easy to be processed. It is also called liquid silicone rubber (LSR or LSE) as well.

To compare additional silicone rubber and condensation silicone rubber, it does not only have advantages like no side products to be produced in vulcanization, the small shrinkage rate and deep vulcanization, it also has better sealability than condensation type in high temperature. Secondly, additional liquid silicone rubber has a significant advantage: simple processing and low cost. This is due to the advantages of additional silicone rubbers like small molecular quantity, low viscosity, convenient formation which could skip the processes of mixing, preformation and post-processing which allow the installation of automation to be easier and to save manpower and energies as well. This also means a short processing period and high efficiency. Therefore, although additional silicone rubber’s raw material is a little more expensive than common silicone rubber, but the total cost is lower than common silicone rubber, especially in manufacturing small-size products.

Additional silicone rubber not only has good mobility, but also has the properties like fast vulcanization. It also has solidification in room temperature and it could also be done in high temperature, its high-temperature vulcanization could be done in few seconds.

Properties of Additional Silicone Rubbers

Additional silicone rubber usually consists of base polymer, crosslinking agent, catalyst, inhibitor, filler and additive. It is according to the way of packaging products, it could be divided into single-component and double-component.

For single-component, it could be grouting material, coating material and FIGP sealing agent.

For double-component, it could be grouting material, coating material, soft moulding material, optical fiber coating material, liquid injection formation material and ball slim powder.

Single-component additional silicone rubber will mix the components mentioned above and to be stored in a lower temperature. When using it, just to increase the temperature and it could restore the activity of catalyst to make the additional reaction to crosslink the elastomer.

Double-component additional RTV silicone rubber could get chemical materials by different groups and to be packed independently: To package catalyst and organic silicone polymers which contain vinyl functional groups as one component, and to pack polysiloxane crosslinking agent which contains hydrogen as another component. When using it, to match the two components at a certain ratio and to heat a little could get the additional reaction to crosslink the elastomer.

Double-component additional RTV silicone rubbers have subcategories like elastic silicone gel, silicone rubber, foam body and spherical differentiation. The former ones have lower strength while the higher one has higher strengths. By adjusting designs and using inhibitors to additional reactions to control vulcanization speed, we could produce products which could be applied in varied industries and purposes. It is the rubber whose crosslinking density has been modified and to be existed together with solids and liquids. It could be used as anti-shocking material in electronics, automotive and medical industries. Additional silicone rubber’s manufacturing process could achieve continuously production. At present, the additional silicone rubber sold on market is mainly double-component RTV silicone rubber. However, it is since single-component ones have advantage like simple storage and transportation, convenient using and better properties to compare with double-component ones, the trend is leading to single-component ones.

Additional liquid silicone rubbers have a wide range of applications. It could not only replace high-temperature compounding rubbers, but also could alter some parts of RTV silicone rubber to increase its property level. Additional liquid silicone rubber could be used as coating materials of electronics and optical fibers, the protection coating material of chips, the adhesion rubber, coating rubber and many other similar industries. Also, it could be used to make optical solidification products as well.

If we add special-made organic silicone resin as the reinforcing agents, we could get transparent vulcanized rubber which has excellent mechanical strength. It is mainly used in coating of electrical parts, the coating material of optical fibers and the soft tissue fillers of human body. In mechanical industries, it is widely used in moulding resins, paraffin wax and concrete. By making full use of high simulation, non-corrosion, simple formation and easy demoulding properties of additional silicone rubber, it could be used as excellent material of moulding which could be applied in copying of relics and artifacts. RTV phenylene silicone rubber could be used as adhesion sealing material in atomic industry, nuclear engine and aerospace and the isolation protection layer of electrical engine.

Summary

Liquid Silicone Rubber is a common organic silicone product in today’s global market; it is very popular and could be considered as one of the largest sold organic silicone product in the world. Also, not only for liquid silicone rubber, but also for other types of silicone rubbers we could also get the goods news of their sales performance on both of domestic and international market.