1. Four factors to consider when choosing accelerator
1.1 Rubber type
Different rubber has different properties, different vulcanization system, different vulcanization system to choose different types of accelerator, should consider the match between them.
1.2 Promoter quality
The quality of accelerator is one of the key issues for formulation engineer. On the market now, still exist many with counterfeit true, the phenomenon that fills an excellent with time, must be careful when choosing so, otherwise the vulcanization that will affect rubber directly or prevent ageing to wait for a respect.
1.3 Influence on the properties of mixing and vulcanizing rubber
Accelerators are involved in the formation of rubber space network structure during vulcanization, which has a direct relationship with the structure of vulcanized rubber, i.e. its physical and mechanical properties and aging properties. The accelerator can soften the mixture, increase the plasticzation of the mixture, and change the processing property of the mixture.
1.4 Charring performance
The accelerator has a decisive influence on the scorch time (that is, the duration of the rubber material before the beginning of hot vulcanization). Therefore, the selected accelerator should make the rubber material have a considerable burning time, which has a significant effect on the operation safety of the rubber material in mixing, calendering, pressing or injection process, the flow of the rubber material at the beginning of vulcanization and the adhesion of the fabric. Especially in recent years, in order to improve the production efficiency, the processing conditions are more and more strict, and the requirements for the anti-scorch performance of rubber materials are more and more high. However, too long scorch time will lead to the increase of the total curing time, which is not only not conducive to the improvement of labor efficiency, but also has an adverse effect on the deformation of mould-free vulcanization products in the vulcanization process.
The scorch resistance of accelerator is directly related to the critical temperature of vulcanization (that is , the temperature at which accelerator is not significant. At this temperature above the promoter activation, the full play of its vulcanization. Unfortunately, most accelerators have not yet been measured at this temperature. When multiple promoters are used together, some promoters are inhibited and some promoters show greater activity even below their critical temperatures.