Polishing sheet and method of producing same

Abstract

A polishing sheet suitable for precise polishing is produced by arranging polishing particles as a single particle layer on a base sheet and includes a base sheet and a polishing layer made of polishing particles and a binder resin for fixing the polishing particles that are arranged as a single particle layer. The polishing particles protrude partially from the surface of the binder resin, being covered or not covered with a thin film of the binder resin.

1 . A method of producing a polishing sheet having polishing particles distributed in a single-layer formation contained in a polishing layer formed on a surface of a base sheet; said method comprising:
 an application step of applying a binder resin for fixing said polishing particles to said polishing layer;   a charging step of charging a specified quantity of said polishing particles in a same polarity;   a dispersing step of transporting and electrostatically dispersing said charged polishing particles to said base sheet having said binder resin applied thereto; and   a hardening step of hardening said binder resin on said base sheet having said polishing particles dispersed thereto;   wherein said binder resin is applied to the surface of said base sheet to a thickness no greater than the average diameter of said polishing particles.   
     
     
         2 . The method of  claim 1  wherein the thickness of said binder resin applied to the surface of said base sheet is two thirds or less and one tenth or more of the average diameter of said polishing particles. 
     
     
         3 . The method of  claim 1  wherein said polishing particles are preliminarily classified according to their uses. 
     
     
         4 . The method of  claim 1  wherein said charging step comprises sending said polishing particles into a metallic tube and forming charged particles with said same polarity by frictional charging. 
     
     
         5 . The method of  claim 1  wherein said polishing particles are charged to 1 kV-20 kV in said dispersing step. 
     
     
         6 . The method of  claim 1  wherein portions of said polishing particles are exposed as cutting edges from the surface of said binder resin after said dispersing step. 
     
     
         7 . The method of  claim 1  wherein said polishing particles have an areal density of 30%-95% on said polishing sheet. 
     
     
         8 . The method of  claim 1  wherein dry powder with water content of 5% or less is used as said polishing particles. 
     
     
         9 . The method of  claim 1  wherein an ultraviolet-setting resin is used as said binder resin. 
     
     
         10 . A polishing sheet comprising a base sheet and a polishing layer formed on a surface of said base sheet, wherein said polishing layer is formed with polishing particles and a binder resin that fixes said polishing particles, said polishing particles are distributed in a single layer, said polishing particles protrude in part from a surface of said binder resin or protrude from the surface of said binder resin with parts thereof covered with a thin film of said binder resin.