CRUSHING MATERIAL REDUCING GRINDING AND LIKE MACHINES

摘要

1502279 Gyratory crushers; jaw crushers MAZEL PLASTICS SYSTEMS Ltd 3 Dec 1975 [3 Dec 1974] 52287/74 Heading B2A [Also in Division C3] A machine part in particular a crushing marble 2 for a gyratory crusher, or a jaw of a jaw crusher comprises a rotatable metal portion and a layer of shock-absorbing backing material 4 in close contact therewith. The backing material is a filled polyurethane resin composition, the resin being derived from a cold curing system in which the polyol constituent is comprised of three components. The first comprises one or more polyether polyols each with at least two hydroxyl groups per molecule; the second comprises one or more polyols each having at least two hydroxyl groups per molecule and each containing both ether and ester groups; and the third comprises one or more polyether diols. The polyisocyanate constituent comprises at least one aromatic polyisocyanate and is present in an amount such that there is an excess of isocyanate groups over hydroxyl groups in the system.