An Original Anti-Reversion Nitrosamine-Free Curing Agent As An Alternative To TMTD

The development of a new curing system has to answer a series of constraints about health, safety and environment issues or regulations. The use of an activated  poly-ter-butylphenol disulfide (as the Mixland+ TBP 75 GA) is a response to this challenge. This activated poly-ter-butylphenol disulfide (TBP) is a fully nitrosamine free curing agent and a sulphur donor.       TBP by itself reacts with a kinetic similar to that of thiazole accelerators. Moreover, TBP has a very good synergistic effect with various curatives, particularly with the sulfenamides (ex: CBS), and, at a least degree, with the diphenylguanidine (DPG).
       The survey shows through an experimental design the possibility to replace TMTD in a NR compounds by a mix of TBP and CBS and/or DPG. The TBP brings an efficient anti-reversion effect, which makes the NR compounds cured at high temperature without degradation, with keeping a good processability for injection moulding, for instance. This synergy efficiently enables TBP to liberate either sulphur or hybrid bonds. The lower cure rate of the curing system based on the TBP makes this compound more suitable for moulding thick parts than a TMTD based compound. Moreover, the tear resistance is kept and the other mechanical properties are equivalent or better. The compression set is improved, without any nitrosamine generation. At last, but not least, this chemical does not generate either blooming or smell.