Ultra fine fiber polishing pad and method for manufacturing the same

Abstract

A method is provided for making a polishing pad. In the method, ultrafine fiber-generating fibers are made into a non-woven fabric with two sides. At least one of the sides of the non-woven fabric is made a dense layer. The non-woven fabric is coated with a polymer. Because of the dense layer, the polymer cannot penetrate the non-woven fabric. The ultrafine fiber-generating fibers are converted to ultrafine fibers. Since the dense layer prevents the polymer from penetrating the ultrafine fiber-generating fibers, the ultrafine fibers remain a high concentration of fiber. The ultrafine fibers are transformed into nap. Therefore, the polishing pad is made with a polishing layer that includes the nap. The concentration of fiber of the polishing layer is higher than 80%.

1 . A polishing pad comprising ultrafine fibers and a polymer that binds the ultrafine fibers, the polishing pad comprising a polishing layer that is made dense in order to include a concentration of fiber higher that of the remaining portion of the polishing pad.  
   
   
       2 . The polishing pad according to  claim 1  wherein the concentration of fiber of the polishing layer is higher than 80%.  
   
   
       3 . The polishing pad according to  claim 1  wherein the fineness of the ultrafine fibers is lower than 0.05 dtex.  
   
   
       4 . A method for making a polishing pad, the method comprising the following steps of: 
 making ultrafine fiber-generating fibers into a non-woven fabric with two sides;    making at least one of the sides into a dense layer;    coating the non-woven fabric with a polymer that forms a coating;    converting the ultrafine fiber-generating fibers to ultrafine fibers; and    processing the coating on the dense layer so that the fineness of the ultrafine fibers on the dense layer is lower than 0.05 dtex.    
   
   
       5 . The method according to  claim 4  wherein the step of making the dense layer includes the step of heating the side of the non-woven fabric at a temperature higher than 100 degrees Celsius.  
   
   
       6 . The method according to  claim 5  wherein the step of making the dense layer includes the step of pressing the side of the non-woven fabric while heating the side of the non-woven fabric.  
   
   
       7 . The method according to  claim 4  wherein the step of processing the coating comprises the step of grinding the coating.  
   
   
       8 . A method for making a polishing pad, the method comprising the following steps of: 
 making ultrafine fiber-generating fibers into a non-woven fabric with two sides;    coating at least one of the sides with a dissolvable substance;    coating the non-woven fabric with a polymer that forms a coating;    washing away the dissolvable substance;    converting the ultrafine fiber-generating fibers to ultrafine fibers; and    processing the coating on the dense layer so that the fineness of the ultrafine fibers on the dense layer is lower than 0.05 dtex.    
   
   
       9 . The method according to  claim 8  wherein the dissolvable substance is selected from a group consisting of polyvinyl alcohol, methyl cellulose, sodium bicarbonate and amylase.  
   
   
       10 . The method according to  claim 8  wherein the step of processing the coating comprises the step of grinding the coating.  
   
   
       11 . The method according to  claim 8  wherein the sequence of the step of washing away the dissolvable substance and the step of converting the ultrafine fiber-generating fibers to ultrafine fibers is changeable.