PURPOSE: To improve abrasion resistance by burying abrasive granules in a specific porous polyurethane resin matrix.
CONSTITUTION: A diol component [e.g. a mixture of a diol contg. polyorganosiloxyl groups with poly(hexamethylene carbonate) diol], a diisocyanate (e.g. isophorone diisocyanate) in an ant. contg. excess NCO groups, and, if necessary, a chain extender (e.g. isophoronediamine) are reacted at 30-120°C for 1-10hr, and the reaction product is, if necessary, molded to give a porous polyurethane resin matrix having a number-average mol.wt. of 5000-100,000, polyorganosiloxyl groups in the side chains of the molecule, the number of repeating units in the group of 10-1000, and a content of the group of 0.1-50 pts.wt. based on 100 pts.wt. solid polyurethane resin. Abrasive granules (e.g. silicone dioxide abrasive granules) are buried in the matrix to give an abrasive material.
AIZAWA HIROYUKI