Crosslinked polyurethane elastomer belt prodn. - by casting elastomer cylinder, curing and converting into small square section strip on lathe, and standing strip into belts

摘要

Long elastic strips are produced by casting a cylindrical-section with polyurethane elastomer on at least the outside surface and turning this into a continuous article 1 to 5 mm across and preferably a square section 2 x 2 mm. A hot-pour prepolymer with cross-linking agent for curing at 90 deg.C is cast into a cylindrical mould with vertical axis containing a steel 200 mm dia. core at the centre, so as to produce an elastomer moulding with 500 mm o.d. and length 500-1,000 mm. After curing this and then post-curing it its steel core is mounted in a lathe. Using a high speed steel cutter it is turned into 2 x 2 mm strip 1,000 mm long from a first layer and, using a feed rate of 2 mm per turn, a length of 750 meters. The products can make polyurethane strips 50-100 m long which are stranded regularly into a belt of high mechanical strength and an extension 7 times its length. ADVANTAGE - The method is an inexpensive, simple, and technologically satisfactory way of producing elastic lengths of suitable dimensions for making polyurethane elastomer endless belts.