Rubber vulcanization system
Unsaturated rubber usually uses the following types of vulcanization systems: sulfur, organic disulfides and polysulfides, thiazoles, diphenylguanidines, zinc oxide and stearic acid-based vulcanizing agents. This is the most versatile cure system. However, the heat-resistant oxygen aging performance of the vulcanizate obtained is not high.
Alkylphenol resin. Polyhalides (such as hexachloroethane for polybutadiene rubber, styrene-butadiene rubber and nitrile rubber), hexachloro-p-xylene. Bifunctional reagents [such as quinones, diamines, azo and phenylazo derivatives (for J-based rubber and ethylene-propylene rubber), etc.]. Bismaleimide, diacrylate. Divalent metal acrylate (methacrylate), pre-polyether acrylate.
Rubber vulcanization process method I. Traditional rubber vulcanization process
1.The main factors affecting the vulcanization process:
Sulfur dosage. The larger the amount, the faster the vulcanization speed, and the higher the degree of vulcanization that can be achieved. The solubility of sulfur in rubber is limited. Excess sulfur will be precipitated from the rubber surface, commonly known as "sulfur spray". In order to reduce the sulfur injection phenomenon, it is required to add sulfur at the lowest possible temperature, or at least below the melting point of sulfur. According to the requirements of the use of rubber products, the amount of sulfur in soft rubber generally does not exceed 3%, the amount of sulfur in semi-rigid rubber-generally about 20%, the amount of hard rubber can be as high as 40% or more. Vulcanization temperature. If the temperature is 10C higher, the vulcanization time will be shortened by about half. Because rubber is a poor thermal conductor, the vulcanization process of the product is different due to the temperature difference of its various parts. In order to ensure a relatively uniform vulcanization degree, thick rubber products are generally vulcanized by gradually increasing temperature and low temperature for a long time.
2. Vulcanization time: This is an important part of the vulcanization process of the microwave curing oven. The time is too short and the vulcanization degree is insufficient (also known as undersulfur). If the time is too long, the degree of vulcanization is too high (commonly known as over sulfur).