Vulcanization refers to the fact that rubber is added with a crosslinking agent such as a vulcanizing agent and an accelerator at a certain temperature and pressure. It is a process in which a linear macromolecule is transformed in a three-dimensional network structure. The most traditional vulcanizing agent is sulfur, and “vulcanization” is also The natural rubber is named after the use of sulfur as a cross-linking agent for cross-linking. At present, the most commonly used vulcanizing agent in the rubber products industry is still sulfur. In the sulfur vulcanizing system, the sulfur and the accelerator can be divided in three types: the ordinary sulfur vulcanization system, the semi-effective vulcanization system, and the effective vulcanization system. The characteristics of the sulfur vulcanization system are different.
1. Different amount of sulfur: The ordinary sulfur vulcanization system is from the traditional vulcanization system, and the amount of sulfur is between 2-3 parts, and it is used together with appropriate amount of accelerator and active agent; the amount of sulfur in the semi-effective vulcanization system is higher than the traditional sulfur vulcanization system. The amount of sulfur used is small, or sulfur is used to replace part of the sulfur, the general amount of sulfur is between 0.8-1.5 parts, the total amount of sulfur donor and accelerator is 1-1.5 parts or more; the amount of sulfur is the best for the effective curing system. It usually consists of 0.3-0.5 parts of sulfur and 3-5 parts of accelerator, or no sulfur at all. A high amount of high-efficiency sulfur carrier is used as a vulcanizing agent and cooperates with the accelerator to increase the activity of the vulcanization system.
2, vulcanizate structural characteristics of different: ordinary sulfur vulcanized rubber compound after vulcanization of the main cross-linked by multi-sulfur bond, very little sulfur and disulfide cross-linking; vulcanized rubber vulcanized with a semi-effective vulcanizing system inside the polysulfide bond, The proportion of low-sulfur bonds is roughly half; when the effective vulcanization system is vulcanized, the compound produces mainly mono- or poly-sulfur bonds, accounting for more than 90%.
3, vulcanizate performance characteristics are different: the traditional sulfur vulcanized rubber after vulcanization has excellent dynamic and static mechanical properties, high tensile strength, wear resistance, fatigue cracking performance is excellent, but the poor resistance to heat aging oxygen; The vulcanizates of the effective vulcanization system are superior to the vulcanizates cured by ordinary vulcanization systems in terms of aging resistance, heat resistance, and anti-sulfidation anti-raw properties, and have moderate tensile strength, elasticity, and fatigue resistance, and are suitable for use in rubber products under dynamic conditions. The effective vulcanization system has good anti-reversion and vulcanization uniformity when vulcanized, vulcanized rubber has good heat resistance, compression deformation resistance, good aging performance, and low heat generation, and is suitable for the production of rubber products and sealing products with large thickness, but It should be noted that vulcanizates vulcanized with an effective vulcanization system are inferior in tensile strength, elasticity and fatigue resistance.
The characteristics of different vulcanization systems are different. Different rubber products and reclaimed rubber products must be vulcanized according to actual needs.
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