The appearance of the vulcanizing agent is paste or powder, its molecular weight is 268.2, and the highest melting point must be above 195 degrees Celsius. It has a wide range of effects, mainly divided into inorganic and organic categories. No matter what kind of action it is, it will cause great harm to the human body.
The vulcanizing agent can make the rubber molecular chain cross-linking reaction, so that the linear molecules form a three-dimensional network structure, the plasticity is reduced, and the elastic strength is increased. Except for certain thermoplastic rubbers that do not need to be vulcanized, natural rubber and various synthetic rubbers need to be formulated with a vulcanizing agent for vulcanization. After vulcanization, rubber has valuable use value, and its mechanical properties are greatly improved.
It is divided into two categories: inorganic and organic.
The former category includes sulfur, sulfur monochloride, selenium, tellurium and so on. The latter category includes sulfur-containing accelerators (such as accelerator TMTD), organic peroxides (such as benzoyl peroxide), quinone oxime compounds, polysulfide polymers, urethanes, and maleimide derivatives. Wait.
Rubber vulcanizing agents include elemental sulfur, selenium, tellurium, sulfur-containing compounds, peroxides, quinone compounds, amine compounds, resin compounds, metal oxides and isocyanates. The most commonly used are elemental sulfur and sulfur-containing compounds.
Vulcanization accelerator
Any substance in the rubber compound that can accelerate the vulcanization reaction rate, shorten the vulcanization time, reduce the vulcanization temperature, reduce the amount of vulcanizing agent, and improve or improve the physical and mechanical properties of the vulcanized rubber is collectively called vulcanization accelerator, or accelerator for short.
Accelerators can also improve the production efficiency of vulcanization and the quality of vulcanized rubber, make the degree of vulcanization of thick products uniform, and reduce product costs.
There are many types of accelerators used in the rubber industry. According to their chemical composition and properties, they can be divided into two categories, inorganic accelerators and organic accelerators. Except for individual cases, organic accelerators are commonly used. Due to its large promotion effect, good vulcanization characteristics, excellent physical and mechanical properties of vulcanizates, rapid development and a wide variety of types.
For example: combined with sulfur, accelerator MPMCZ or TMTD, this initiator, vulcanized diene rubber (natural rubber, styrene butadiene rubber, nitrile rubber, synthetic isoprene rubber) can prolong the scorch time, reduce heat generation, and stabilize High tensile strength and excellent resistance to vulcanization reversion. At the same time, it can also increase H extraction. It is suitable for high temperature vulcanization of rubber (183℃). The dosage is 2-3phr. It is suitable for large tires and thickened and enlarged products. As a vulcanization accelerator for neoprene, it can significantly improve the scorch resistance of the rubber compound, and is suitable for processing neoprene in the southern high temperature season.
The vulcanizing agent can not only improve the adhesion, but also improve the compression set, and it can also be a scorch retarder. Such a powerful vulcanizing agent can also be dissolved in water. Of course, it is not only a product of chemical properties, but also has unique physical properties.
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