Patent ID: 9463550
Filing Date: 2016-10-11
CPC Classification: B24B,B24D

Claim Text:
1. A method of making a polishing layer for polishing a substrate selected from at least one of a magnetic substrate, an optical substrate and a semiconductor substrate, comprising: providing a liquid prepolymer material, wherein the liquid prepolymer material reacts to form a material comprising a poly(urethane); providing a plurality of thermally expandable hollow microspheres; wherein each thermally expandable hollow microsphere in the plurality of thermally expandable hollow microspheres has a poly(vinylidene dichloride)/polyacrylonitrile copolymer shell; and, wherein the poly(vinylidene dichloride)/polyacrylonitrile copolymer shell encapsulates an isobutane; exposing the plurality of thermally expandable hollow microspheres to a carbon dioxide atmosphere for an exposure period of >3 hours to form a plurality of treated hollow microspheres; combining the liquid prepolymer material with the plurality of treated hollow microspheres to form a curable mixture; allowing the curable mixture to undergo a reaction to form a cured material, wherein the reaction is allowed to begin ≦24 hours after the formation of the plurality of treated hollow microspheres; and, deriving at least one polishing layer from the cured material; wherein the at least one polishing layer has a polishing surface adapted for polishing the substrate.