Polishing pad and method for making the same

Abstract

The present invention relates to a polishing pad and method for making the same. In the invention, a liquid-state polymer material is directly formed on the surface of a base material, and then the liquid-state polymer material is solidified to form a flat grinding layer. Whereby, the polishing pad has high unity and flatness. The grinding layer has attenuated structures and a plurality of holes, thus increasing the storage ability of polishing particles distributed in a polishing liquid. In addition, the polishing pad has high compression ratio, so the polishing pad can compactly contact a polishing workpiece, and will not scratch the surface of the polishing workpiece scratched. Therefore, the polishing effect and quality will be improved.

1 . A polishing pad, comprising:
 a base material, formed by covering a fiber layer with a polymer, and having a surface; and   a grinding layer, bonded to the surface, and having a plurality of holes, wherein each of the holes is in a shape of column, the holes are distributed over a thickness that is at least one half of the overall thickness of the grinding layer, the depth of some of the holes is greater than one half of the overall thickness of the grinding layer, and the holes communicate with each other, some of the holes are completely disposed inside the grinding layer.   
     
     
         2 . The polishing pad according to  claim 1 , wherein the fiber layer is made of a cloth material. 
     
     
         3 . The polishing pad according to  claim 2 , wherein the cloth material is a non-woven cloth. 
     
     
         4 . The polishing pad according to  claim 1 , wherein the material of the fiber layer is selected from PP, PET, or nylon. 
     
     
         5 . The polishing pad according to  claim 1 , wherein the polymer is continuous foam. 
     
     
         6 . The polishing pad according to  claim 5 , wherein the polymer is selected from PU, PP, PET, or polymer resin. 
     
     
         7 . The polishing pad according to  claim 1 , wherein the surface is flattened, and the grinding layer is made of one material selected from PU, PP, PET, or polymer resin. 
     
     
         8 . The polishing pad according to  claim 1 , wherein some fibers in the fiber layer are exposed on the surface, and are further covered by the grinding layer. 
     
     
         9 . The polishing pad according to  claim 1 , wherein the compression ratio of the polishing pad is 5% to 50%. 
     
     
         10 . The polishing pad according to  claim 1 , wherein the recovery ratio of the polishing pad is greater than 80%. 
     
     
         11 . The polishing pad according to  claim 1 , wherein a thickness of the polishing pad is 0.5 to 3.0 mm. 
     
     
         12 . The polishing pad according to  claim 1 , wherein the density of the polishing pad is 0.2 to 0.6 g/cm 3 . 
     
     
         13 . A method for making a polishing pad, comprising:
 (a) providing a base material, wherein the base material is formed by covering a fiber layer with a polymer and has a surface;   (b) forming a liquid-state polymer material on the surface; and   (c) solidifying the liquid-state polymer material to form a grinding layer, wherein the grinding layer is bonded to the surface and has a flat surface; and   (d) immersing the flat surface of the grinding layer in a coagulating basin, so as to form a plurality of holes in the grinding layer through single surface exchange, wherein each of the holes is in a shape of column rather than in a shape of water drop, the holes are distributed over a thickness that is at least one half of the overall thickness of the grinding layer, the depth of some of the holes is greater than one half of the overall thickness of the grinding layer, the holes communicate with each other, and some of the holes are completely disposed inside the grinding layer.   
     
     
         14 . The making method according to  claim 13 , wherein Step (a) further comprises:
 (a1) providing a fiber substrate;   (a2) immersing the fiber substrate in a polymer solution, so that the polymer solution covers the fiber substrate; and   (a3) solidifying the polymer solution to form the base material.   
     
     
         15 . The making method according to  claim 13 , wherein in Step (b), the liquid-state polymer material is formed on the surface by coating. 
     
     
         16 . The making method according to  claim 13 , wherein in Step (c), to the liquid-state polymer material is solidified by natural drying. 
     
     
         17 . The making method according to  claim 13 , wherein in Step (c), the liquid-state polymer material is solidified by air drying.