Friends who often come into contact with silicone products in their lives must often hear the word vulcanization. How many friends know why vulcanization is needed? All silicone rubber products need to be vulcanized because after vulcanization, the mechanical properties of silicone rubber are greatly improved.
Silicone rubber vulcanization is divided into two stages
The first stage is divided into raw rubber, reinforcing agent, additive, vulcanizing agent and structure control agent for raw material mixing to obtain silicone rubber raw materials, and the raw materials are blended into semi-finished materials;
The second stage is in Put the material and the finished material into the metal mold, heat the mold, extrude, extrude, inject and other processes, the machine is forced and the product is catalyzed and solidified, and the mold is formed at high temperature!
In the vulcanization process of silicone rubber, the common vulcanization processes are as follows:
一.The vulcanization process of silicone rubber can be divided into three methods: direct vulcanization, indirect vulcanization and mixed gas vulcanization, which depends on the vulcanization medium and vulcanization method.
- Direct vulcanization: Put the product directly into hot water or steam medium for vulcanization.
- Indirect vulcanization: place the product in hot air for vulcanization. This method is usually used for some products with strict appearance requirements, such as rubber shoes, etc.
- Mixed gas vulcanization, first use air vulcanization, and then use steam to vulcanize directly. This method can not only overcome the shortcomings of steam vulcanization affecting the appearance of the product, but also overcome the shortcomings of slow heat transfer due to hot air, long vulcanization time, and easy aging.
二.According to the different vulcanization process, silicone rubber products can be divided into cold vulcanization, room temperature vulcanization and hot vulcanization.
- Cold vulcanization: Cold vulcanization can be used for vulcanization of film products. The rubber products are immersed in a carbon disulfide solution containing 2% to 5% sulfur chloride, and then washed with water.
- Room temperature vulcanization: When room temperature vulcanization, the vulcanization process is carried out at room temperature and normal pressure, such as using room temperature vulcanization mortar (mixed rubber solution) for seams and repairs of bicycle inner tubes.
- Thermal vulcanization: Thermal vulcanization is the main vulcanization method for silicone rubber products.