Thioureas

- Feb 26, 2019-

Other new varieties of accelerators Currently, new types of accelerators are being researched to obtain accelerators with high efficiency of vulcanization, good processing safety, good resistance to reversion and high aging resistance. In addition, the variety of sulfur donors has gradually increased, and non-sulfur cross-linking systems have emerged. Moreover, it has been recognized that toxic promoters such as ethylene thiourea are being eliminated.

(1) Triazine promoter The most important of these is bis(2-ethylamino-4-diethylaminotriazinyl-6) disulfide, which promotes higher potency than conventional accelerators. Fast and safe to process. The vulcanization rate in natural rubber is similar to that of the accelerator NOBS, and the processing safety is between NOBS and CZ. When the amount is small, in the case of containing 1.5 to 2.35 parts of natural rubber, only 0.3 parts can be used instead of 0.5 parts of sulfenamide. The accelerator can improve the anti-reversion property of sulforaphane at low sulfur dosage, and can be used in styrene-butadiene rubber, isoprene rubber and butyronitrile.

(2) Promoters such as thiocarbamoyl sulfenamide are mainly N-oxydiethylenethiocarbamoyl-N-oxydiethylene sulfenamide, which has high safety and vulcanization speed. Fast, the promotion is great. Suitable for styrene butadiene rubber, nitrile rubber, EPDM rubber and other general synthetic rubber. The compound used in an amount of 0.67 parts was vulcanized faster than 1 part of the sulfonyl accelerator. And can get satisfactory operational safety performance. The activity above 149 ° C is very large, while below 149 ° C can be added a small amount of accelerator NOBS, M or DM. (3) Thiophosphoryl accelerator bis(diethylthiophosphoryl) trisulfide This accelerator can be used as a sulfur donor in natural rubber. When part or all of the sulfur is replaced, the heat resistance of the vulcanizate can be improved, and the reversion property and compressive deformation property can be improved at the time of high temperature vulcanization. It is an excellent accelerator in EPDM rubber, safe in operation, fast in vulcanization, excellent in heat resistance, non-blooming, and excellent in compression set resistance. It differs from many other accelerators and sulfur and sulfur donors in that it does not cause degradation of the polyester fibers in contact with the rubber.