Polishing pad and polishing method

Abstract

Provided is a polishing pad having a high following performance even when a surface to be polished is a curved face. A polishing pad ( 1 ) in an embodiment of the present invention includes a polishing layer ( 2 ) having a polishing face ( 21 ) and a support layer ( 3 ) that is formed from a material softer than the polishing layer ( 2 ) and is fixed to a face ( 22 ) opposite to the polishing face ( 21 ) of the polishing layer ( 2 ). The support layer ( 3 ) has a hardness of not less than 30 and less than 70 in terms of F hardness.

1 . A polishing pad comprising:
 a polishing layer having a polishing face; and   a support layer softer than the polishing layer and fixed to a face opposite to the polishing face of the polishing layer, wherein   the support layer has a hardness of not less than 30 and less than 70 in terms of F hardness.   
     
     
         2 . The polishing pad according to  claim 1 , wherein the support layer has a density of 20 kg/m3 or more and 60 kg/m3 or less. 
     
     
         3 . The polishing pad according to  claim 1 , the polishing pad being used to polish a coating face of a synthetic resin. 
     
     
         4 . The polishing pad according to  claim 1 , wherein the polishing layer has a hardness of 40 or more determined immediately after close contact with a pressure foot in a test method defined by “Spring hardness test, type C test method” in appendix 2 in JIS K7312: 1996. 
     
     
         5 . The polishing pad according to  claim 1 , wherein the polishing layer is a nonwoven fabric or a suede. 
     
     
         6 . The polishing pad according to  claim 1 , further comprising a groove formed on the polishing face of the polishing layer, wherein
 when the polishing pad is viewed from a perpendicular direction to the polishing face, a ratio (Sm/Sk) of a total area Sm (cm2) of the groove to a total area Sk (cm2) of the polishing face is 0.30 or more and 0.80 or less, and a ratio (Vm/Sk) of a total volume Vm (cm3) of the groove to the total area Sk (cm2) of the polishing face is 0.07 or more.   
     
     
         7 . The polishing pad according to  claim 6 , wherein when the polishing pad is viewed from the perpendicular direction to the polishing face, the polishing layer has a circular shape, the polishing face has a diameter of 10 mm or more and 200 mm or less, and the polishing face is smaller than a surface to be polished of an object to be polished. 
     
     
         8 . The polishing pad according to  claim 6 , wherein the groove has a width of 0.5 mm or more and 5.0 mm or less. 
     
     
         9 . The polishing pad according to  claim 6 , wherein the groove has a depth of 0.5 mm or more and 2.5 mm or less. 
     
     
         10 . The polishing pad according to  claim 6 , wherein the polishing layer has an A hardness of 70 or more determined by a method in accordance with JIS K 6253 and has a sparse-dense structure on a surface of the polishing layer, and the sparse-dense structure has a sparse portion area ratio of 52% or more and 96% or less. 
     
     
         11 . The polishing pad according to  claim 6 , the polishing pad being used to polish a face of a resin including a resin coating. 
     
     
         12 . The polishing pad according to  claim 6 , wherein the groove at least partially reaches an outer edge of the polishing layer, and an end of the groove is open. 
     
     
         13 . The polishing pad according to  claim 1 , wherein
 the polishing layer has a disk shape,   the support layer has a truncated cone shape,   a disk face of the polishing layer is fixed to a bottom face having a larger diameter of two bottom faces of a truncated cone included in the support layer, and   a bottom face having a smaller diameter of the two bottom faces is a support face to which a pressing force is applied.   
     
     
         14 . The polishing pad according to  claim 1 , wherein when the polishing pad is viewed from the perpendicular direction to the polishing face, the polishing layer and the support layer have a circular shape, and a face of the polishing layer on the support layer has a smaller diameter than a diameter of a face of the support layer on the polishing layer. 
     
     
         15 . A polishing method comprising:
 using the polishing pad according to  claim 1 ;   supplying a polishing composition containing abrasives onto a surface to be polished of an object to be polished; and   pressing the polishing face against the surface to be polished and moving the polishing pad to polish the surface to be polished.   
     
     
         16 . The polishing method according to  claim 15 , wherein the surface to be polished is larger than the polishing face and includes a curved face. 
     
     
         17 . A polishing method comprising:
 using the polishing pad according to  claim 6 ; and   pressing the polishing face against a surface to be polished of an object to be polished and moving the polishing pad to polish the surface to be polished.   
     
     
         18 . The polishing method according to  claim 17 , wherein a highly viscous polishing composition containing abrasives is supplied between the surface to be polished and the polishing pad, and
 by manually moving the polishing pad or by attaching the polishing pad to a polisher of an industrial robot and moving the polishing pad by operation of the industrial robot to perform the polishing.   
     
     
         19 . The polishing method according to  claim 18 , wherein the polishing composition includes an emulsion containing the abrasives and at least one additive selected from an oleum, an emulsion stabilizer, and a thickener. 
     
     
         20 . The polishing pad according to  claim 2 , the polishing pad being used to polish a coating face of a synthetic resin.