Century Creation (International) Co., Ltd

Main Factors Affecting Rubber Vulcanization

21-04-2020

  Un-vulcanized rubber does not produce cross-linking between molecules, which has not good physical and mechanical properties and has little practical value. Rubber vulcanizing agent can cross-link rubber molecules through heat treatment or other methods, and make them form a three-dimensional network structure, which greatly improves its properties, especially a series of physical and mechanical properties such as tensile stress, elastic rubber, hardness, tensile strength, etc..

  The rubber molecules undergo a chemical reaction under the action of heating and crosslinking agent of sulfur, and crosslink into a three-dimensional network structure, which is called rubber vulcanization. Vulcanization is the last process of rubber processing, which can obtain a stereotyped design and has practical values for rubber products.

  Main Factors Affecting Rubber Vulcanization:

  Sulfur Usage Amount.

  The higher the usage amount, the faster the curing speed and the higher the degree of curing. Sulfur has limited solubility in rubber. Excessive sulfur will precipitate on the rubber surface, commonly known as Sulfur Spray. In order to reduce the phenomenon, it is required to keep the temperature as low as possible, or at least keep it in the melting point and sulfur environment. According to the usage requirements of rubber products, the amount of sulfur in soft rubber is generally not more than 3%, that in semi-hard rubber is generally about 20%, and that in hard rubber can be as high as over 40%.

  Vulcanization temperature.

  Under the condition of high temperature 10℃, the curing time can be shortened by half. As rubber is a poor conductor, the vulcanization process of the product varies with the temperature difference of each part. In order to ensure a more uniform degree of vulcanization, thick rubber products adopt generally rising sulfide and low temperature for a long time.

  Vulcanization time.

  This is an important part of the vulcanization process. Too short time will make low curing (also known as sulfur deficiency), but too long time will make high curing degree (commonly known as sulfur). Thus, only an appropriate degree of vulcanization (commonly known as positive vulcanization) can ensure the best comprehensive performance.


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