Rubber additives are of many kinds, the role is also more complex, currently used in the international total of more than 3000 kinds. According to the nature of their role, can be grouped into the following categories; vulcanizing agents, accelerators, active agents, reinforcing fillers, plasticizers, antioxidants, coloring agents, as well as latex-specific additives and other special-purpose additives.
The vulcanization process is mainly the use of rubber in the double bond cross-linking reaction, in which the rubber hydrocarbon dehydrogenation of rubber radicals can be directly combined with each other and cross-linking, but also through the sulfur yellow or other non-sulfur compounds cross-linking occurs.
1、Elemental sulfur vulcanizing agent
Typical representative is sulfur yellow, which is the most basic and important vulcanizing agent in the rubber industry. Adopting common sulfur yellow-accelerator-activator system, the resulting vulcanizing agent has the advantages of good comprehensive performance and low cost.
2、Sulfur giving body
Sulphur donors are compounds that release sulphur during vulcanization and can therefore be used without or with less sulphur. The main varieties are the disulfide compounds or tetrasulfides of thiuram. The thiurams are used as both vulcanizing agents and accelerators.
3、Peroxide sulfiding agent
Including inorganic peroxides, silicone organic peroxides and organic peroxides. Widely used in the industry of organic peroxides, the main varieties of di-tert-butyl peroxide ( DTBP ), peroxide of diisopropylbenzene ( DCP ) and 2,5-=methyl 2,5 a bis-hexane.
4、Quinone derivatives
Typical varieties are p-quinone dioxime, xylenoyl p-quinone dioxime, etc., mostly used as vulcanizing agent of butyl rubber. The vulcanized rubber vulcanized with quinone has the advantages of good ozone resistance, fast vulcanization speed, and high constant elongation strength, so it is widely used in the manufacture of electrical rubber products and vulcanized capsules and water tires, although the tensile strength and compression and water-long deformation are poorer than that of sulphur rubber vulcanized with sulphur yellow. In order to improve the scorchability of p-benzoquinone dioxime, it is usually prepared as = benzoyl derivative.
　
5、Polyfunctional amine compounds
are mainly used for crosslinking of specialty synthetic rubbers such as acrylate rubbers and fluoroelastomers. Polyamine vulcanization of fluorine rubber is characterized by the mechanical strength of vulcanized rubber, compression and water long deformation is small, high temperature and long-term aging can still maintain good physical and mechanical properties, but easy to burn, processing safety is not conducive to the gradual development of "closed amine" compounds, such as hexamethylenediamine carbamate, ethylenediamine carboxylate to improve processing safety. Safety.
6、Resin vulcanizing agent
It is mainly used for the vulcanization of butyl rubber to make it have excellent heat resistance and high temperature resistance. At present, it has been widely used in the industry, if you want to accelerate the speed of vulcanization, generally need to add stannous chloride as an active agent. The main disadvantage of resin vulcanizing agent is that it has a big tendency to scorch. The main varieties are p-tert-butyl phenolic resin, p-tert-octyl phenolic resin and so on.