BigPatents India

This invention relates to a composite rubber pipe for use in a flexible traffic delineator and a process for preparation thereof. The composite rubber pipe comprises an inner rubber pipe preferably based on natural rubber or on a combination of 100 to 75 parts of natural rubber with 0 to 25 parts of synthetic rubber preferably butadiene rubber. The outer rubber pipe is based on ethylene propylene Diene Monomer (EPDM) and is extruded over the inner pipe. In the composition for the inner pipe, the additives used are a peptiser, a mixture of FEF carbon black and calcium carbonate as fillers, powder sulphur as vulcanization agent, a vulcanization accelerator, a vulcanisation activator consisting of a mixture zinc oxide and stearic acid, accelerator activator-cum-curing agent, an oil, an anti-oxidant, an anti-ozonant and a plasticizer. The additives used in the composition of the outer rubber pipe include a peptiser, powder sulphur as vulcanisation agent, a mixture of FEF carbon black and calcium carbonate as fillers, a combination of zinc oxide and stearic acid as vulcanization activator, a vulcanization accelerator and an accelerator activator-cum-curing agent. The process of preparation of the inner pipe involves masticating the rubber along with the additives on a rolling machine to obtain sheet form, cutting the sheet into small rectangular strips and extruding into pipes at a temperature of 90 to 100 deg.C followed by curing. The composite pipe is prepared by masticating EPDM with additives on a rolling machine obtaining sheet form, cutting the sheets into strips and extruding over the inner pipes at a temperature of 90 to 100 deg. C followed by curing at 100 to 120 deg.C for 15 to 30 minutes to obtain the desired composite pipe.