What is the organosilicone compounds?
Organic silicone compounds are those containing Si-C bonds and at least one organic substituent is directly connect to the silicon atom, such as CH₃SiH₃,CIH₂CSiCI₃, C ₆ H ₅ SiCl ₃, C₂ H ₅ Si (OMe) ₃, (CH ₃) ₃ SiOSi (CH ₃) ₃, [(CH ₃) ₂SiO] ₄ etc are organic silicon compounds. Accordingly, SiH₄,SiC,Na₂SiO₃ and H₃SiCN ₄ belong to inorganic silicone compounds. In China, it is customary to call silicone monomer and polysiloxane as "silicone compound" or "silicone", and polysiloxane resin as silicone resin, polysiloxane liquid as silicone oil, polysiloxane rubber as silicone rubber.
What is the liquid silicone rubber?
Liquid silicone rubber is made of low molar mass linear silicone polymer as base glue, and crossing linker agent, catalyst, filler and other additives. According to its vulcanization mechanism is divided into condensation type and addition type, according to the vulcanization temperature is divided into high temperature vulcanization (HTV) and room temperature vulcanization (RTV), according to usage and packaging form is divided into single component and double components.
What is the addition type liquid silicone rubber?
The addition type liquid silicone rubber is an important development and application of Speier hydrosilication in silicone rubber vulcanization. The principle is the siloxane containing vinyl and the multi-Si-H bond siloxane are catalyzed by the eighth group transition metal compounds (such as Pt, etc.) for hydrosilylation addition reaction to form a new Si-C bond, so that linear siloxane is cross-linked into a network structure. The reaction equation as follows:
Hydrosilication reaction theoretically does not generate by-products, and has the characteristics of high conversion rate, controllable cross-linking density and speed, in this way silicone rubber has better comprehensive performance.
Condensation Liquid Silicone Rubber VS Addition Liquid Silicone Rubber
|
Feature |
Condensation |
Addition |
|
Before vulcanization |
Low viscosity (700mm²/s), putty shape |
Low viscosity (500mm²/s), putty shape |
|
Mixture ratio (Base polymer:cross linker) |
(100:0.5)~(100:10) |
(100:3)~(100:100) |
|
Validity |
Depending on the amount of catalyst, usually short |
Relatively long and easy to control |
|
Vulcanization speed |
Depending on the amount of catalyst, humidity has a big effect, temperature has a small effect |
Humidity has a great effect, and can be quickly vulcanized at high temperature, but humidity has no effect |
|
Deep vulcanization |
Some products do not work |
All kinds of products |
|
By-products |
Alcohol, water, hydrogen |
No |
|
Catalyst poisoning |
No |
Do not contact with N, P, S organic compounds, Sn, Pb,Hg, Bi, As ionic chemicals, acetylene and polyvinyl chemicals |
|
Electrical insulation |
The vulcanization decreases initially,then returns to normal |
No effect |
|
Line shrinkage/% |
<1.0 |
<0.2 |
|
Heat resistant |
Low in closed system |
positive |
|
Mechanical strength Stripping sexual adhesion Heat and water resistance Flame retardant |
performance can be improved by adjusting formula |
performance can be improved by adjusting formula |
Single component & double component liquid silicone rubber
Addition type liquid silicone rubber, usually composed of base polymer, cross linker, catalyst, filler and other additives. According to the way of packaging, divided into two categories: single component and double components. The former one is mixed the above components with inhibitors or capsule-type platinum catalyst stored at low temperature. When used, by increasing the temperature, the catalyst activity can be restored, after addition reaction then turn into elastomer.The latter one is combined into two packages according to the chemical properties . When used, after mixing in a certain proportion or heating up slightly, after addition reaction then cross link into elastomer.
Hot Tags: high-end liquid silicone rubber, China, suppliers, manufacturers, factory, wholesale, price, pricelist, free sample
