The use of certain block copolymers and their compounds in a number of end-uses and especially in footwear, is rapidly expanding. For example, in the footwear industry, certain block copolymer compounds are being used in large volume in the manufacture of a wide variety of shoes including canvas shoes, sport shoes, and dress shoes. The block copolymers may be utilized for this purpose for soling, foxing, innersoles and the like. These compositions are disclosed in Hendricks et al, U.S. Pat. No. Re. 28,236. In general, these shoe component compositions usually comprise a mixture of block copolymer, extending oil, polystyrene and possibly a filler. For the most part, these block copolymer compositions have proven to be particularly advantageous in many respects, including flexibility, processability, lack of vulcanization requirement and wet slip. However, in certain respects, shortcomings have been noted. For example, commercial compounds should be free from delamination, free from elephant hide, and free from flow markings and marring. With respect to many styles in the casual and dress shoe areas of footwear, one of the major shortcomings of the block copolymer compounds such as those referred to in U.S. Pat. No. Re. 28,236 is the lack of a smooth appearance. Present block copolymer compounds lack the smooth, relatively unblemished surface which is characteristic of compression molded vulcanized conventional rubber, injection molded poly(vinyl chloride) or leather. A new process has now been found that produces a smooth dull surface and also is non-delaminating.
USPTO Backgrounds
USPTO Backgrounds