Sulfur, peroxide, quinone oxime, resin, metal oxide and other vulcanization systems can be used according to the requirements of rubber and rubber products.Among them, sulfur sulfide system is divided into ordinary sulfide system, effective sulfide system and semi-effective sulfide system.Sulfur curing system in general synthetic rubber and half use the more general synthetic rubber, metal oxide vulcanization system is mainly used for neoprene (CR), quinone oxime and resin curing system is mainly used for butyl rubber (IIR), peroxides and resin curing system is mainly used for ethylene propylene rubber (EPR), natural rubber (NR) and styrene-butadiene rubber (SBR).Special rubber [such as thiokol (LP), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM) (F K M), silicone rubber, fluorine rubber (M V (Q), fluorine silicone rubber (FVMQ)] basic belong to saturated rubber, do not contain a double bond, the can’t afford to the crosslinking effect on sulfur, so need to adopt the sulfur curing system, such as metal oxide, peroxide, organic amine salt vulcanization system, etc.In recent years, the acrylate rubber (ACM) has basically adopted sulfur vulcanization system.
(1)sulfur.Sulfur powder is the most commonly used vulcanizing agent in the rubber industry.With the development of radial tire and color rubber products, insoluble sulfur (IS), which does not spray frost, does not affect the adhesion performance and product appearance, IS widely used.IS IS mostly used in NR tire compound, which can improve the adhesion performance between compound and skeleton material, avoid frosting and prolong the storage time of compound. IS IS also used in BR tire compound in a small amount.
(2)Peroxide Peroxide.In addition to IIR and halogenated butyl rubber (XIIR), other rubbers, especially MVQ, EPDM, NBR, HNBR, CM, CR and thermoplastic elastomer, can be cured by peroxide.Peroxide vulcanized rubber crosslinking key is C – C key, the key can than single sulfur sulfur vulcanization rubber keys, double sulfur and sulfur more keys keys can be big, therefore peroxide vulcanized rubber hot oxygen aging performance, compression permanent deformation is small, difficult to bloom, no sulfide to return the original phenomenon, but its tensile properties, strain and fatigue resistance performance is poorer.
(3)Peroxide Resin.In order to improve the heat resistance and aging resistance of rubber, many kinds of rubber (IIR, NR, SBR and NBR, etc.) have been widely used as a cross-linking agent resin (such as alkyl phenolic resin, etc.).Resin vulcanized IIR adhesive has good heat resistance and small permanent deformation, and has become the most important adhesive for manufacturing vulcanized capsules.Resin as IIR curing agent, curing speed is slow, and curing temperature is high.Phenolic resin vulcanization system is also commonly used in the preparation of rubber/plastic blends such as EPDM/PP.
(4)Peroxide Metal oxide.For rubber containing halogens or carboxyl groups such as CR, CM and XIIR, metal oxides are used as vulcanizing agents.The common metal oxides are zinc oxide and magnesium oxide. The active zinc oxide and light magnesium oxide are the best.
(5)Peroxide Sulfur donor.Sulfur donor is a vulcanizing agent that can decompose sulfur in the vulcanization process of rubber.Its adhesive is characterized by better heat resistance than sulfur adhesive, excellent compression deformation resistance, and good coke resistance, not easy to spray frost.However, most sulfur donors have been placed on the list of restricted use due to their toxicity, such as morpholine sulfide agents DTDM and TMTD.
(6)Peroxide Amines.Amine compounds are often used in FKM and ACM as vulcanizing agents, mainly including methylene amines and anilines.