What does secondary vulcanization of silicone rubber for silicone encapsulation mean?

1、 The meaning of secondary vulcanization of silicone gel
Secondary vulcanization of silicone refers to the process of heating silicone products after a first vulcanization molding. Through secondary vulcanization, the cross-linking structure inside silicone products can be further improved, thereby enhancing their physical properties and chemical stability. The secondary vulcanization of silicone is usually carried out at high temperatures, and the choice of temperature and time depends on the specific requirements and material properties of the silicone product.
2、 The principle of secondary vulcanization of silicone gel
The principle of secondary vulcanization of silicone is mainly based on the thermal crosslinking reaction of silicone materials. During the vulcanization process of silicone products, the raw rubber molecules in the silicone material undergo cross-linking reactions through the action of the vulcanizing agent, forming a three-dimensional network structure. However, due to the time and temperature limitations of a single vulcanization, some raw rubber molecules may not fully participate in the crosslinking reaction, resulting in unstable performance of silicone products. Therefore, through secondary vulcanization, the raw rubber molecules that have not participated in cross-linking can continue to react, further improving the cross-linking structure of silicone products.
3、 Process flow of secondary vulcanization of silicone gel
The process flow of secondary vulcanization of silicone mainly includes the following steps:
1. Pre treatment: Clean and deburr the silicone products formed by one-time vulcanization to eliminate surface impurities and defects, preparing for subsequent secondary vulcanization.
2. Heating stage: Place the silicone product into the vulcanization equipment and gradually heat it up to the temperature required for secondary vulcanization. During the heating process, it is important to control the heating rate to avoid stress in silicone products caused by rapid temperature changes.
3. Constant temperature stage: After the silicone product reaches the temperature required for secondary vulcanization, maintain a constant temperature for a period of time. During the constant temperature stage, the raw rubber molecules inside the silicone product continue to undergo cross-linking reactions, further improving the cross-linking structure of the silicone product.
4. Cooling stage: After the constant temperature is reached, gradually lower the temperature of the vulcanization equipment to cool the silicone products to room temperature. During the cooling process, it is also important to control the cooling rate to avoid stress on silicone products caused by rapid temperature changes.

4、 Application of Silicone Secondary Vulcanization
Secondary vulcanization of silicone has a wide range of applications in the production of silicone products. Through secondary vulcanization, the physical properties and chemical stability of silicone products can be significantly improved, such as hardness, tensile strength, wear resistance, aging resistance, etc. Therefore, the secondary vulcanization of silicone is of great significance in the manufacturing of high-performance silicone products.
In practical production, the application of silicone disulfide involves multiple fields, such as automobile manufacturing, electronic appliances, medical devices, etc. For example, in the field of automobile manufacturing, components such as silicone seals and shock absorbers need to undergo secondary vulcanization to improve their high temperature resistance, oil resistance, wear resistance, and other properties; In the field of electronic appliances, components such as silicone buttons and pads also need to undergo secondary vulcanization to improve their conductivity, insulation, and other properties.
5、 Precautions for Secondary Vulcanization of Silicone
When conducting secondary vulcanization of silicone, the following points should be noted:
1. The selection of temperature and time should be determined based on the specific requirements and material characteristics of silicone products, to avoid adverse effects on the performance of silicone products caused by excessively high or low temperature and excessively long or short time.
During the vulcanization process, it is important to control the heating and cooling rates to avoid stress in silicone products caused by rapid temperature changes.
3. The vulcanization equipment should be kept clean and dry to avoid adverse effects of impurities and moisture on the performance of silicone products.
Before conducting secondary vulcanization, sufficient pretreatment should be carried out on silicone products to eliminate surface impurities and defects, in preparation for subsequent secondary vulcanization.
In summary, the secondary vulcanization of silicone encapsulated rubber is an important step in the production process of silicone products. Through secondary vulcanization, the performance and stability of silicone products can be significantly improved, meeting the demand for high-performance silicone products in various fields. In actual production, we need to select appropriate vulcanization process parameters based on the specific requirements and material characteristics of silicone products, and strictly control each link in the vulcanization process to ensure the quality and performance of silicone products.