New Types of Premature Vulcanization Inhibitors

Abstract

The activity of the thiosulfonamides and dithiotrichloromethanes as retarders is apparently a result of their ability to function as BTSH trapping agents. The effect of substituents on retarder efficiencies seems consistent with a mechanism involving a three-way competition between crosslinking, retardation, and decomposition of retarder to non-functional products. The key reaction responsible for trapping BTSH probably involves a nucleophilic displacement. Substituents which favor this type of displacement increase efficiency when they are on the portion of the retarder molecule which combines with BTSH; when they are on the portion which becomes the leaving group, they evidently promote decomposition, causing a net decrease in retarder efficiency.

Studies on ethylene‐propylene‐diene rubber modification by N‐chlorothio‐N‐butyl‐benzenesulfonamide

“…Figure 8 shows the curing curves of NR/BR/EPDM blends according to Table IV with different CTBBS‐amounts modified LENB‐EPDM. Compared with the unmodified EPDM, blends with modified EPDM have a longer scorch time due to the amine‐effect from CTBBS 18, 19. Modified EPDM also shows greater torque values than pure EPDM, whereas with different CTBBS amounts, there is little difference.…”