One of the major applications of sulfur powder in the industry is that it can be used in the vulcanization of rubber. This type of sulfur is generally called rubber-specific sulfur powder. It is a professional rubber vulcanizing agent, which can greatly improve the physical and chemical properties of rubber. In the process of rubber vulcanization, several factors will affect the process.
Sulfur dosage: The larger the dosage of special sulfur powder for rubber, the faster the vulcanization speed and the higher the vulcanization degree. However, the solubility of sulfur in rubber is limited, and excess sulfur will be precipitated from the surface of the rubber, commonly known as sulfur spray. To reduce this phenomenon, it is necessary to add sulfur at the lowest possible temperature, or at least below the melting point of sulfur. According to the requirements of rubber products, the sulfur content in soft rubber is no more than 3%, the sulfur content in semi-hard rubber is about 20%, and the sulfur content in hard rubber is as high as 40%.
Vulcanization temperature: If the temperature is higher than 10 ℃, the curing time will be shortened by about half. Since rubber is a poor thermal conductor, the vulcanization process of the product varies depending on the temperature of each part of the product. In order to ensure a more uniform degree of vulcanization, thick rubber products are generally heated gradually and vulcanized for a long time at low temperature.
Curing Time: This is an important part of the curing process. If the time is too short, the degree of vulcanization will not be sufficient. The vulcanization time is too long and the degree of vulcanization is too high. Only an appropriate degree of vulcanization, commonly known as positive vulcanization, can ensure the best overall performance.