| abstract |
A pipe joint sealer for providing a watertight joint in metal pipe, cast concrete pipe, plastic pipe and the like is disclosed. The pipe joint sealer prevents fine dirt and sand from entering the pipe through the joint. The pipe joint sealer is comprised of an absorbent material such as low density, open cell, resilient foam which is saturated with a quantity of water reactive urethane prepolymer. The urethane prepolymer saturated foam is sandwiched between two layers of a geotextile fabric such as polypropylene which permit moisture to come into contact with the urethane prepolymer saturated foam. Moisture causes the urethane prepolymer saturated foam to expand and thereby form a dynamic watertight seal. Drying of the urethane prepolymer saturated foam causes it to shrink back toward its original volume. Thereafter, the pipe joint sealer of the present invention forms a new watertight seal each time it is wetted. This allows the pipe joint sealer to compensate for shifts in joint position caused by settling and the like. Plant root growth inhibitors such as copper, plant copper compounds and herbicides may be included in the urethane prepolymer. |