The accelerators are condensates of aliphatic aldehydes or amines (aliphatic or aromatic amines). It is acidic. When the varieties are different, their vulcanization activity and the obtained vulcanization properties are different. Its activity range generally ranges from quasi-super to slow. It has good flatness and the scorch time is not long. The most important feature is that the obtained vulcanized rubber has excellent aging resistance. Among them, a less active promoter (such as hexamethylenetetramine) is used as a second promotion of thiazole or sulfenamide accelerators. Only the butyraldehyde aniline condensate is a stronger accelerator and acts as the first accelerator when it is produced with the thiuram accelerator. (1) Hexamethylenetetramine The trade name is Promoter H. This product is a white to light yellow crystalline powder, almost odorless and bitter. It has a stimulating effect on the skin. The specific gravity is 1.3. Heating to 263 ° C will sublimate and partially decompose. Slightly deliquescent. The critical temperature is 140 ° C. When the vulcanization temperature is low, it is not very active, and the risk of scorch is small. Used mostly as a second accelerator. No discoloration, no pollution, no decomposition. Mainly used for transparent and thick-walled products. (2) n-Butylaldehyde and aniline condensate The trade name is accelerator 808. This product is a reddish brown or amber viscous oily liquid with a special odor. The proportion is 0.94~0.98. In the air, the color becomes darker and the specific gravity increases. But the performance remains the same. Isolated air storage is stable. The vulcanization flatness is high, the critical temperature is 120 ° C, and the optimum vulcanization temperature is 120-160 ° C. Good dispersibility in dry glue. Suitable for rubber and hard rubber containing reclaimed rubber.
Sunnyjoint supply HMT-3H and HMT-10 to many tyre plants ,for example Hankook,Michelin.Nexex etc.