POLYEPICHLOROHYDRIN VULCANIZATION WITH 2-R-4, 6-DIMERCAPTO-s-TRIAZINE
1973 Volume 46 Issue 9 Pages 779-787
Details
1973 Volume 46 Issue 9 Pages 779-787
Vulcanizing rate of polyepichlorohydrin (CHR) with 2-R-4, 6-dimercapto-s-triazine (I) is influenced by the structure of R, and the rate increases in order of R: SH<OCH3<N(C4H9)2. In addition, the rate is remarkably increased by the copresence of amines with pKa over 9 such as 1, 3-diphenylguanidine. The organic or inorganic salts of the amine as well as the amine generator such as N-cyclohexyl-2-benzothiazole sulfenamide or Cu-dibutyldithiocarbamate show the similar accelerating activity. The mechanical properties of the vulcanizates with I are improved with the increasing of hydrohobicity of R, i. e, in order of SH<N(C2H5)2<N(C4H9)2<N(C6H5)2, N(C6H11)2<N(C8H17)2. The thermal ageing stability is not improved in the presence of commone antioxidant such as phenyl-β-naphthyl-amine and t-butylphenol novolak. The latent vulcanizing agents, however, show the remarkable stabilizing activity. The best examples are 2-mercaptobenzi-midazole and Ni-dibutyldithiocarbamate, which are used as antioxidant. The vulcanizing compositions of trithiocyanuric acid-MgO-1, 3-diphenylguanidine, and 2-dibutylamino-4, 6-dimercapto-s-triazine-MgO give the most excellent vulcanizates in thermal ageing stability and mechanical property in comparing with the well known composition, e.g. 2-mercaptoimidazoline-Pb3O4, and hexamethylenediamine carbamate-Pb3O4.
