Application Analysis of Rubber Accelerator in Synthetic Rubber

Vulcanization system auxiliaries, protective system auxiliaries and processing auxiliaries play an important role in the formulation of synthetic rubber and are the main factors affecting the properties of rubber products. This paper mainly introduces the application of these rubber auxiliaries in synthetic rubber.

1. Vulcanization system auxiliaries

The auxiliaries of vulcanization system are mainly composed of vulcanizing agent, accelerator and active agent, and their dosage accounts for about 10% of the amount of raw rubber. According to the saturation of synthetic rubber, sulfur, metal oxides, peroxides and amine compounds can be used to vulcanize a variety of systems.

1.1 vulcanizing agent

According to the different performance requirements of rubber and rubber products, sulfur, peroxide, quinone oxime, resin, metal oxide and other different curing systems can be used. Among them, sulfur sulfide system is divided into ordinary sulfide system, effective sulfide system and semi-effective sulfide system. Sulfur vulcanization system is used more in general synthetic rubber and semi-general synthetic rubber. Metal oxide vulcanization system is mainly used in neoprene rubber (CR), quinone oxime and resin vulcanization system is mainly used in butyl rubber (IIR), peroxide and resin vulcanization system is mainly used in ethylene propylene rubber (EPR), natural rubber (NR) and styrene butadiene rubber (SBR). Special rubber [such as polysulfide rubber (LP), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM), fluorine rubber (F K M), silicone rubber (M V Q), fluorine silicone rubber (FVMQ), etc.) basically belong to saturated rubber, do not contain double bonds, sulfur yellow can not cross linking effect on it, Therefore, it is necessary to use non-sulfur sulfide system, such as metal oxide, peroxide, organic amine salt sulfide system. In recent years, acrylic rubber (ACM) has basically adopted sulfur sulfide system.

(1) Sulfur yellow. Common powder sulfur is a vulcanizing agent commonly used in rubber industry. With the development of radial tires and colored rubber products, insoluble sulfur (IS), which does not spray frost and does not affect the adhesion performance and product appearance, has been widely used. IS IS mostly used in NR tire compound, which has the function of improving the bonding property of rubber-skeleton material, avoiding spraying frost and extending the storage time of rubber compound. Is IS also used in butadiene rubber (BR) tire compound in a small amount.

(2) peroxides [2]. In addition to IIR and halogenated butyl rubber (XIIR), the rest of the rubber especially MVQ, EPDM, nitrile butadiene rubber (NBR), hydrogenated nitrile butadiene rubber (HNBR), CM, CR and thermoplastic elastomers almost can be vulcanized with peroxide. The crosslinking bond of peroxides vulcanizates is C-C bond, and its bond energy is larger than that of single sulfur bond, double sulfur bond and polysulfur bond of sulfide vulcanizates. Therefore, peroxides vulcanizates have excellent heat-resisting oxygen aging property, small compression deformation, not easy to spray frost, no vulcanizate reactivation phenomenon, but their tensile properties, strain properties and fatigue resistance are poor.

(3) resin. In order to improve the heat resistance and aging resistance of the compound, many kinds of adhesive (IIR, NR, SBR, NBR, etc.) have widely used resins (such as alkyl phenolic resin, etc.) as crosslinking agents. The resin vulcanized IIR adhesive has good heat resistance and small compression deformation, and has become the main adhesive for the manufacture of 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 EPDM/PP and other rubber and plastic blends.

(4) metal oxides. Halogenated or carboxyl containing rubber such as CR, CM and XIIR requires metal oxides as vulcanizing agents. The common metal oxides are zinc oxide and magnesium oxide. Active zinc oxide and light magnesium oxide are preferred.

(5) sulfur donor. Sulfur donor is a sulfide agent that can decompose sulfur during rubber vulcanization. The characteristics of the compound are better heat resistance than the sulfide compound, excellent compression and deformation resistance, and good coking resistance, not easy to spray frost. However, due to the toxicity of most thiothione donors, such as morpholine containing sulfides DTDM and TMTD, they are listed as restricted in use.

(6) amine compounds. FKM and ACM often use amine compounds as curing agents, mainly methylene amine, aniline compounds, etc.