The production process of liquid silicone rubber mainly includes steps such as raw material preparation, mixing rubber, molding, vulcanization, post-processing and quality inspection. The following is a detailed explanation of these steps:
1. Raw material preparation
The main raw material of liquid silicone is silica (silicon dioxide), and chemicals such as boric acid and phosphoric acid are added as needed. These raw materials need to be ground and screened to ensure purity and uniformity. In addition, for some colored or special performance liquid silicone products, corresponding colorants or additives need to be prepared.
2. Mixed rubber
Proportioning and mixing: Liquid silicone raw materials are usually divided into A glue and B glue. During the mixing process, it is necessary to use a quantitative device to accurately control the ratio of A glue and B glue (usually 1:1) and fully mix them through a static mixer. If the product requires color, it is also necessary to be equipped with a color pump group and a color metering part to add and mix the colorant.
Plasticization: The mixed rubber needs to go through a plasticization system to ensure that it has good fluidity and plasticity, which is convenient for subsequent molding operations.
3. Molding
The molding methods of liquid silicone mainly include compression molding and injection molding.
Compression molding method: The mixed rubber or preformed semi-finished product is loaded into the mold cavity, and then pressed on the machine, and heated and vulcanized at the same time to obtain the finished parts. This method has simple equipment and strong versatility, but the production efficiency is relatively low.
Injection molding method: The rubber is directly injected into the mold cavity for vulcanization through a rubber injection machine. This method has high production efficiency and stable and reliable product quality, but requires expensive injection equipment. During the injection process, parameters such as injection speed, temperature and pressure need to be controlled to ensure the quality of product molding.
4. Vulcanization treatment
The molded liquid silicone product needs to be vulcanized to solidify it and achieve the required hardness and shape stability. The vulcanization process is usually carried out in a vulcanizer, and the temperature and time need to be controlled. After the vulcanization is completed, the product will have stable physical and chemical properties.
5. Post-processing
After the vulcanization is completed, the product needs to be trimmed and polished to remove burrs and residues to make its surface smooth and tidy. In addition, necessary cleaning and drying treatments are required to ensure the cleanliness and dryness of the product.
6. Quality inspection
Quality inspection is required after each production link. Quality inspection includes appearance inspection, size inspection, performance inspection, etc. to ensure that liquid silicone products meet relevant standards and customer requirements. Only products that pass the inspection can enter the next link or be packaged and shipped.
In summary, the production process of liquid silicone is a complex and delicate process that requires strict control of parameters and quality requirements in each link to ensure the quality and performance of the final product.