Considering from the formula design method, the causation phenomenon in the process of operation or storage is mainly due to the improper selection of vulcanization system. Therefore, in the formulation should be as far as possible to choose a higher after effect or critical temperature of the accelerator, can also be added to further improve the anti-coke agent.
Fillers also have an impact on coke burning, acidic fillers such as tank method carbon black, with delayed vulcanization, generally not easy to cause coke. Furnace carbon black is alkaline, has the effect of promoting vulcanization, and is easy to cause coke. Carbon black with high structure is also easy to cause scorch.
Adding softener generally has the effect of delaying coke firing, increasing the amount of softener can improve the coke firing property. However, many surfactants with -OH, -NH₂, -COOH and other groups will make the coke performance worse, and should be paid attention to when used.
The use of anti-coke agent is one of the most effective means to improve the safety of rubber processing. Common anti-burning agents for general rubber are benzoic acid, phthalic anhydride, o-hydroxybenzoic acid (salicylic acid), n-nitrosodiphenylamine and so on. In recent years, there have been many new high-efficiency anti-coke agents, among which the performance is better such as PVI of Dalian Richon Company, which has a good anti-coke effect on all sulfur vulcanized dienes and low unsaturation rubber, and its activity is not affected when used with other rubber additives, which is a very effective anti-coke agent.
The effect of mixing system on frost spraying：From the formula point of view, the main reason is that the amount of these compounds exceeds its saturation solubility. Therefore, in the formulation design, attention should be paid to the amount of sulfur and accelerator should be appropriate, positive vulcanization should be strictly controlled, and the control of free sulfur should be strengthened, or the dispersability of good varieties (such as insoluble sulfur) and good solubility varieties should be changed. In addition, the appropriate addition of pine tar and Coumaron resin in the compound can increase the solubility of the compound to the above additives, so it can reduce the phenomenon of frost spraying.
