Zisnet cure system

A comparison of cure systems in epichlorohydrin-ethylene oxide copolymer (ECO) is shown in Table 13.12. ETU lead oxide cure system provides good technical properties, but is replaced because of health and environmental concerns. Vulcani-zates cured with non-lead cure systems generally have poorer properties after immersion in water. This can be overcome in the Zisnet cure system by the substitution of a synthetic hydrotalcite (Hysafe 310) for calcium oxide, with some sacrifice in compression set. The substitution of the hydrotalcite for lead oxide in the ETU cure system does not typically provide good water resistance... 

Compression molding may be done with any cure system, but HyTemp NPC is the most efficient one transfer or injection molding is best using HyTemp SC-75, Vanax 829, Zisnet F-PC, or NPC if care is used in processing to keep the compound below a measured temperature of 85°C. 

The effect of reversion on polyepichlorohydrin compounds cured with ETU/red lead is most noticeable however, this may be decreased quite signihcantly by using a Zisnet F-PT cure system and a high AGE content GECO polymer. The effect of AGE content on heat aging may be seen in Table 7.6. In addition, the homopolymers CO or GCO exhibit better heat resistance because of the absence of ethylene oxide. After aging 144 h at 150°C the hardness increase of a CO-based compound is... 

As with most halogen-containing elastomers, polyepichlorohydrin polymers can corrode metal surfaces, but only noticeable under extreme conditions, such as being left in the mold at 200°C for 2 h. The Zisnet F-PT cure system is much better than the ETU/red lead curative package as given in Table 7.8, for Iowct mold fouling and better... 

Three viable cure systems for the CO and ECO elastomers are triazine (Zisnet F-PT), thiadiazole (Echo MPS), and bis-phenol (Dynamar5157/5166). An overview of the systems is given in Table 7.9 [5]. 

The cure rate of the triazine system is readily adjustable as seen in Table 7.10. The triazine, (Zisnet F-PT), curative may be changed by adding varying amounts of certain key ingredients. When using 0.8 pphr of the triazine, 0.2-1.0 pphr of DPG acts as an accelerator and 0.2-1.0 pphr of either Santogard PVl or Vulkalent E/C retards the cure and gives better scorch safety. 

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