Patent ID: 8387167

Claim:
An article having a resin surface on which recessed portions different in size are formed randomly, the article comprising: first recessed portions which are formed by allowing at least one of granular or powdery adhering material to adhere to a surface of an unset resin composition containing air bubbles so that at least a portion of the granular or powdery adhering material bites into the surface and by removing the adhering material after the resin composition is set, and second recessed portions which are smaller than the first recessed portions in size and are formed by allowing some of the air bubbles contained in the unset or set resin composition to open on said surface of the resin composition, the second recessed portions being openings which are formed on the surface of the resin composition when some air bubbles that are contained in the resin composition are broken when removal of the adhering material which is adhered to the surface of the resin composition occurs, wherein an inner diameter of the first recessed portions is in the range of 100 μm to 500 μm, a plurality of the second recessed portions are formed across the entirety of the resin surface so as to be formed across internal surfaces of the first recessed portions comprising depressions on the resin surface, the resin composition comprises a material selected from the group consisting of natural rubber, acrylonitrile-butadiene rubber and chloropene rubber, either alone or in combination, the air bubbles comprise 5 to 30 vol % of the resin composition, and an average diameter of the air bubbles is 50 μm or less.