Carpet tack strip with urethane base

Abstract

The present invention relates to an improved synthetic resinous formulation utilized to form a substrate for retention of carpet while securing tack and pre-nail elements in strip form, and with the pre-nails being adapted to secure the substrate in place along the edge surfaces of the floor and with the tack elements being adapted to retain the edge portions of a carpet in place thereon. The substrate is characterized in that it is formed essentially of a filled polyurethane compound which possesses unusual mechanical properties particularly desirable in the formation of carpet retaining strips. These properties include the flexibility to permit the strip to conform to an irregular floor surface, and furthermore can be readily cut and notched to allow it to be bent to conform to an inside or outside corner. Because of the excellent plastic memory, the carpet retaining tacks are held at a desired angle even when subjected to substantial lateral tension caused by the stretched in-place carpet. The formulation of the polyurethane includes a prepolymer comprising a polyether polyol (35%-40%), a cross-linking agent (15%-20%), a filler consisting essentially of inert ingredients (10%-36%), a catalyst (10%-15) and a chemical blowing or frothing agent (mechanical) (3%-5%), and wherein methylene di-isocyanate is added to the prepolymer components blend (component B), the prepolymer consisting of 80% of the blend, balance methylene di-isocyanate (component A) (20%).