Guangdong Yufeng Industries Co., Ltd.
Guangdong Yufeng Industries Co., Ltd.

The Refining Process of Silicone Rubber

Apr 13 , 2023

Preparation of silicone rubber

1. Silicone rubber is a high saturation of raw rubber, usually not sulfur vulcanization, using hot vulcanization, hot vulcanization using organic peroxide as a vulcanizing agent, therefore, raw rubber shall not contain active substances that can react with peroxide decomposition products (such as carbon black, some organic promoters and antioxidant, etc.), otherwise, it will affect the vulcanization.

2. Silica gel products are generally used at high temperatures, and their complexes should remain stable at high temperatures. Therefore, inorganic oxides are usually used as reinforcing agents.

3. Silicone rubber is non-polar rubber, silicone rubber in trace acid and alkali and other polar chemical agents under the action of easy to cause the cracking and rearrangement of siloxane, resulting in the reduction of silicone rubber heat resistance. So the selection of complex must consider its acid and alkaline, but also should consider the acid and alkaline peroxide cracking products, so as not to affect the performance of vulcanized rubber.

The refining process of silicone rubber

First, "material selection". According to the use of the production environment and quality requirements to choose the appropriate silicone rubber material, such as wear resistance, oil resistance, acid resistance, alkali resistance, high and low-temperature resistance, tensile strength and so on these requirements, and to determine which material is more reasonable.

Second, refine. Most of the time, the raw materials we purchase back are just raw glue, which can not be directly used for production. We also need to carry out secondary processing, which is called refining. Refining is adding accelerators, colour powder and other auxiliary forming ingredients in raw glue according to a certain proportion to meet the production requirements.

Third, cut off. After refining, a whole piece of material is obtained, and then the whole piece of material needs to be cut into the final material of the same weight shape and size as we need according to the product structure and size.

Fourth, "shape". After the completion of the above work, the most important step is moulding. We should put the material cut in the previous step into the silicone rubber mould, and carry out hot pressing moulding in accordance with the pre-set process parameters to finally get the appearance size we need. Of course, there are also products that are injected into the mould cavity directly through the injection moulding machine instead of hot pressing moulding. This is similar to the principle of a syringe.

Fifth, "processing/inspection". After forming, we get a whole piece of product. We also need to separate the part of the product we need from the middle, and then remove the raw edge of the product, and check the appearance of the product. So far, a qualified silicone rubber product has completed its whole process.

The curing of silicone rubber

In its unvulcanized state, silicone rubber is a highly viscous gel or liquid. In order to be converted to a solid, it must be cured, vulcanized, or catalyzed. It is usually made into the desired shape in a two-stage process at the time of manufacture and then in an extended post-curing process. It can also be injection-moulded.

Silicone rubber can be cured by a platinum-catalyzed curing system, condensation curing system, peroxide curing system or oxime curing system. For platinum-catalyzed curing systems, the curing process can be accelerated by increasing heat or pressure.

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