What are the selection principles for silicone vulcanization temperature and time?

In the production process of rubber products, silicone vulcanization is a crucial step that directly affects the performance, appearance, and service life of the product. The temperature and time of silicone vulcanization are the two core parameters of the vulcanization process, and their selection principles are crucial for ensuring product quality.
1、 The basic principle of silicone vulcanization
Silicone vulcanization, also known as the cross-linking reaction of silicone rubber, refers to the process in which linear or branched silicone rubber molecules are cross-linked through chemical bonds under the action of a vulcanizing agent to form a three-dimensional network structure. Vulcanized silicone rubber has excellent heat resistance, cold resistance, weather resistance, electrical insulation, and chemical stability, and is widely used in fields such as electronics, electrical appliances, automobiles, and medical care.
2、 Principles for selecting the vulcanization temperature of silicone gel
1. Material characteristics: Different types of silicone materials have different vulcanization characteristics, so when selecting the vulcanization temperature, factors such as thermal stability, crosslinking density, and vulcanization speed of the material need to be fully considered. Generally speaking, silicone materials with good thermal stability can choose higher vulcanization temperatures to improve production efficiency; Silicone materials with lower cross-linking density require a lower vulcanization temperature to prevent excessive cross-linking from causing a decrease in product performance.
2. Type of vulcanizing agent: The type and amount of vulcanizing agent have a significant impact on the selection of vulcanization temperature. Different vulcanizing agents have different activation energies and vulcanization rates, so when selecting the vulcanization temperature, it is necessary to adjust it according to the type and amount of vulcanizing agent. For example, silicone materials using peroxide vulcanizing agents usually choose lower vulcanization temperatures due to their faster vulcanization rate; For silicone materials using sulfur vulcanizing agents, a higher vulcanization temperature can be chosen.
3. Product thickness: The thickness of the product is also one of the factors to consider when selecting the vulcanization temperature. Thicker products require a lower vulcanization temperature due to slower heat transfer to ensure uniform vulcanization inside and outside the product; Thinner products can choose higher vulcanization temperatures to improve production efficiency.
4. Equipment and process conditions: Equipment and process conditions also have a certain impact on the selection of vulcanization temperature. For example, the heating method and temperature control accuracy of the vulcanization equipment, as well as the thermal conductivity of the mold, can all affect the selection of vulcanization temperature. Therefore, when selecting the vulcanization temperature, it is necessary to consider the actual situation comprehensively.

3、 Principles for selecting the vulcanization time of silicone gel
1. Degree of vulcanization: The degree of vulcanization of silicone is the main basis for selecting the vulcanization time. The vulcanization time is too short, the product is not sufficiently vulcanized, and the performance does not meet the standard; If the vulcanization time is too long, it may lead to excessive cross-linking of the product and a decrease in performance. Therefore, when selecting the vulcanization time, it is necessary to set it reasonably according to the performance requirements of the product.
2. Sulfurization temperature: Sulfurization temperature is closely related to vulcanization time. A higher vulcanization temperature can shorten the vulcanization time and improve production efficiency; However, excessively high temperatures may lead to a decrease in product performance. Therefore, when selecting the vulcanization time, comprehensive consideration should be given to the vulcanization temperature.
3. Product thickness and shape: The thickness and shape of the product also affect the choice of vulcanization time. Thicker products require longer vulcanization time due to slower heat transfer; And for products with complex shapes, due to the temperature gradient during the vulcanization process, it is also necessary to extend the vulcanization time appropriately to ensure uniform vulcanization inside and outside the product.
4. Equipment and process conditions: Equipment and process conditions also have a certain impact on the selection of vulcanization time. For example, the heating method and temperature control accuracy of the vulcanization equipment, as well as the thermal conductivity of the mold, can all affect the setting of the vulcanization time. Therefore, when choosing the vulcanization time, it is necessary to consider the actual situation comprehensively.
4、 Summary
The selection principle of silicone vulcanization temperature and time is one of the key factors to ensure the performance and quality of rubber products. When selecting the vulcanization temperature and time, it is necessary to fully consider factors such as material characteristics, type of vulcanizing agent, product thickness, equipment and process conditions, and make reasonable settings based on the performance requirements of the product. By selecting the appropriate vulcanization temperature and time, the vulcanization process parameters can be optimized to improve the performance and quality of rubber products.