Patent ID: 6165397
Filing Date: 2000-12-26
Classification: B29C,B29D,B29K

Abstract:
A method for forming a spin cast item comprising the steps of, mixing together polyurethane materials comprising polyisocyanates with a volume of water selected as a molecule chain extender to provide a time delay before the liquid polyurethane material begin to set up of from 1 to 5 seconds; for a mold having an interior cavity formed to have the shape of an item to be cast, with said mold maintained on a support plate that is journaled to a frame to be axially spun to a speed of between fifty (50) to five hundred (500) RPM, passing the polyurethane materials into an annular trough that is located on or within said mold and is immediately adjacent to and is open around its circumference into the mold cavity to provide an even distribution of polyurethane materials into said mold cavity at said mold cavity inner circumference; prior to the polyurethane materials passed into said annular trough beginning to cure and form a foam, spinning the support plate to introduce centrifugal forces into said polyurethane materials to distribute them from said annular trough evenly in said mold cavity wherein the curing process beings with the polyurethane materials forming a foam that uniformly fills the cavity, and, with continued spinning, the centrifugal forces to uniformly compact said foam at the cavity walls, producing a uniform non-porous skin around a cellular inner core of an item.