Image Number 3 for United States Patent #5605721.
The present invention is directed to an underlayment composition for an artificial playing surface comprised of a butadiene rubber, such as polybutadiene or styrene-butadiene that is commercially available as recycled polycord tires that have been granulized. An inorganic-base moisture-retaining agent such as vermiculite or perlite is also included in the composition in addition to a binder comprised of a mixture of isocyanate polyurethane and an inorganic acid. The present invention also provides a method of making the present composition. The method comprises the steps of mixing thoroughly granulized particles of butadiene rubber in a mixing container, mixing an inorganic-based moisture-retaining component with the butadiene rubber, mixing an acid having a pH .ltoreq.3 with the butadiene rubber and the inorganic-based moisture-retaining component, and mixing an isocyanate polyurethane with the butadiene rubber, the inorganic-based moisture-retaining component and the acid. Finally, the present invention also provides a method of using the present composition which comprises the steps of applying the composition over a conventional foundation base and laying an artificial turf over the underlayment composition.