Reducing Cure Costs with Processable Low Temperature Cure (PLTC) Natural Rubber Compounds for High Duty Engineering Applications

摘要

Natural rubber sulphur-cure compounds associated with reduced manufacturing energy and hence environmental costs have been developed. Technical benefits can also derive from the novel low temperature moulding (40℃) and curing (70℃) procedures involved.rnEssential constituents in these processable low temperature curing (PLTC) formulations are liquid polybutene of a form to induce mouldability at 40℃ and particular ultra-fast accelerators to bring about the 70℃ vulcanisation. Because of project objectives, PLTC recipes developed to date have been targeted for a specific oilfield end-use - manufacturing large complex profiled bonded rubber/metal components which support huge loads and accommodate considerable deformations during service.rnIn this case, besides giving considerable energy savings during curing, reduced shrinkage from lower manufacturing temperatures will improve dimensional features of the product. However, the PLTC approach could be applied to essentially any engineering end-use with rubber, providing that adequate resistance to ageing at service-related elevated temperatures is demonstrated. This approach is potentially applicable, with faster cure systems, to the manufacture of a number of automotive rubber/metal composite components.rnWith work to date, good magnitudes of properties relevant to the project application were achieved, including tensile properties, tear strength, air-ageing resistance, rubber-to-steel bonding and crack growth fatigue. In some of these, the property levels of the high-temperature-cured compound currently used for the project application have been surpassed by those of the PLTC. Also, creep tests lead to the prediction of only a 7% compressive change over 10 years. Acceptable shelf life and fluid absorption levels are also reported.