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The Use of Liquid Addition Silicone Rubber RTV-2

1. Selection and mixing of varieties

The condensation type 2 part silicone adhesive rubber compound can be made to easy to flow low viscosity products according to the needs and even to nonmobile thixotropic or putty products. Therefore, we should first select suitable varieties according to the technical requirements and shapes of the components. For encapsulation parts, the glue should be perfusion type. Suitable crosslinking and catalyst should be selected according to the construction requirements and environmental conditions, and the suitable dosage should be controlled so that the product can be vulcanized at a different time. If the choice is improper and the deployment is unreasonable, what has been done may be wasted.
Add the crosslinker and the catalyst into the binder to a certain proportion, and the mixture can be carried out in the mixer or the original packing barrel. The mixture can be mixed in a clean and dry cup or barrel and can be met by artificial or machine stirring. After mixing, vacuum degassing should be carried out. For tightly packed components, vacuum degassing or pressurized treatment is needed after pouring. After joining the crosslinking system, the addition silicone rubber will gradually thicken and finally become a three-dimensional network elastomer. Therefore, before construction, we should prepare the construction parts to be ready before using them as soon as possible. The user should make a good estimate in advance according to the depth and area of the construction parts, so as not to cause lack of glue or too many ingredients to cause waste. In order to prolong the service life, the mixed rubber can be moved into the cooling cabinet for safekeeping.

2. Vulcanization

The curing rate can be obtained at 23-30 degree temperature and the curing rate can be increased by increasing the temperature. However, it should not exceed 65 percent, and the curing rate is also related to humidity. Exposure to high humidity air can accelerate the curing rate.

3. Adjustment of consistency

In order to meet the technological requirements, when the adhesive is thickened, some thickeners, such as white carbon black, calcium carbonate, diatomite, quartz powder and mica powder, can be used as putty. When the consistency of the rubber needs to be reduced, a low molar mass silica oil with good compatibility or the same structure type can be used as a diluent. When the spraying process is used, the adhesive can be diluted with the organic solution. The commonly used solvents are toluene, xylene and other diluents in the side chain containing fluoroalkyl groups.

4. Coating vulcanization

When RTV-2 is vulcanized, there are by-products such as methanol, ethanol and so on. They need to diffuse from the vulcanizate to the surface. In deep perfusion, because the by-products cannot be released in time, it will affect the internal vulcanization. In order to solve this problem, a stratified perfusion method is adopted in the process, which is favorable for the by-products to leave the glue layer in time, but the operation is more troublesome. If a small amount of vulcanizing accelerator is added to the compound, such as glycerol phosphate and the metal salt, it will be not necessary to separate layer perfusion.
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