US Patent 7465473 Bonding of granular materials to polyolefin surfaces

A permanent, roughened or textured surface is applied to parts molded from polyolefins, particularly from polyethylene by applying to the surface of the part a coating mixture of a tackifier resin and polyolefin particles in a liquid carrier and incorporating a granular or particulate matter in the coating, either by application to the coating or by admixing the granular or particulate matter into the coating mixture. The coated surface is heated to the melt temperature of the polyolefin surface for a short time, sufficient to gel the polyolefin particles of the coating into the surface of the part, but insufficient to cause any thermal distortion of the part.