The main research content of rubber tire vulcanization involves the ecological and environmental problems in the vulcanization process itself and in the process of use, the improvement of vulcanization process, the reduction of scorching and reversion tendency, the promotion of cold vulcanization, the prevention of vulcanizing agent, especially the spraying frost of vulcanization yellow in the finished products, etc.

The general trend of vulcanization system research and development can be summarized as follows: (1) elimination of promoters that may produce nitrosamines; (2) promoters should give the rubber better scorching performance and make the rubber easy to process in the molding process; (3) the vulcanization system is suitable for high temperature vulcanization, which helps to improve productivity; (4) improve the resistance to vulcanization reversion; (5) improve the performance of vulcanized rubber, such as mechanical properties or dynamic properties.

Rubber tire curing system development direction
(a) Reduction of ecological hazards in the use of vulcanization systems
Dust: Vulcanization systems for unsaturated rubber usually use sulfur yellow, and a series of measures are needed to prevent sulfur yellow from flying during weighing and other process operations, such as the use of granulation.

Secondary amine accelerators form secondary amines in vulcanization, and then react with nitro reagents to produce nitrosamines, so secondary amine-based accelerators can generate volatile nitrosamines and be dangerous; primary amine accelerators (including CBBS, TBBS, etc.) do not generate nitrosamines.

Tire compounds often use accelerators DCBS (DZ), can also be used disulfide tetrabenzylthiuram and bismaleimide of the same substance.

It is recommended to add small amounts of CaO, Ca (OH)2 and Ba (OH)2 to polybutadiene and butylamine sulfide vulcanization compounds to prevent the formation of nitrosamines.

In addition, change the reaction conditions, blocking oxygen and other oxidizing agents, can also prevent, reduce the generation of nitrosoamine compounds, such as tire vulcanization using nitrogen vulcanization.

(B) improve the vulcanization process and the use of vulcanized rubber performance
Unsaturated rubber
(1) new vulcanizing agent
Fe (OH)3 as accelerator and triethanolamine can be vulcanized butadiene, acrylonitrile, etc..
New vulcanizing agent based on ethylene thiourea can be used to vulcanize nitrile rubber, butyl rubber, chloroprene rubber and EPDM rubber.

(2) New type of vulcanization accelerator
From hexamethylenediamine and sulfur yellow condensation can be made for isoprene rubber and butadiene rubber of new polymer vulcanization accelerator. This kind of vulcanization accelerator vulcanization flat period is wide, can improve the physical and mechanical properties of vulcanized rubber.

In order to improve the vulcanization rate of unsaturated rubber, often add a second accelerator, such as butyraldehyde and aniline condensate.

(3) New method of reducing scorch rate
The combination of tetrabenzylthiuram disulfide and hyposulfonamide and 2-pyrazine hyposulfonamide is effective for most rubbers vulcanized with sulfur yellow.

For the rubber vulcanized with butadiene rubber, it is recommended to use tetramethyl isobutyl monosulfide.

(4) Reduction of reversion
It is recommended to use the derivatives of diethyl phosphoric acid to reduce the reversion. In addition, sodium hexamethylene bis(thiosulfate), pentachloro-β-hydroxyethyl disulfide, bis(citramide) with tridecylhexaene, diphenyl phosphorodithioate (Ni, Sn, Zn), 1-phenyl- and 1,5-diphenyl-2,4-dithiourea with N-cyclohexylbenzothiazole hyposulfamide, etc. can also be used.

(5) The new method of using sulfur yellow vulcanizing active agent
Usually ZnO (3-5 parts by mass) and stearic acid (1 part) are combined as the active agent of sulfur yellow vulcanization. At present, various methods are used to reduce the amount of ZnO, and even replace ZnO. For example, the ZnO content in rubber can be reduced to 2 parts by mass by heating the accelerator MBT (M) with the accelerator TT and a combination of ZnO and stearic acid to 100-105°C.