Slush Molding
In slush molding, thermoplastic casting in which a liquid resin is poured into a hot, hollow mold where a viscous skin forms; excess slush is drained off, the mold is cooled, and the molded product is stripped out. (answers.com.9/24/2010)
“Plastisol is used for slush molding or slush casting. It is a form of spin casting that is more complex than relatively simple resin casting, but less expensive and less sophisticated than the injection molding used for most plastic products. It involves metal molds that are filled with liquid plastisol. When the open mold cavities are filled, the mold is spun on a heavy duty, high speed centrifuge to force the liquid vinyl into all of the fine detail on the interior of the mold. Then the metal mold is placed into a heating solution, usually an industrial salt heated to about 400 degrees. The liquid vinyl cooks for a few seconds. The mold is then removed from the heating solution and the remaining liquid is poured out. This leaves a thin skin of vinyl on the interior of the metal mold. The mold is then placed back into the heating solution for three to four minutes to cure. After curing, the mold is again removed from the heating solution, cooled with water, and placed on a rack. While the vinyl part is still warm in the mold, it is very flexible and can be removed from the mold with pliers. When the parts cool, they become rigid and are ready for assembly.”
“The metal molds can produce an unlimited number of castings. Unlike the flexible molds used for resin casting, metal molds are not adversely affected by heat. The metal molds allow grouping of several parts in one mold cavity and several mold cavities in one mold for faster production.”
Recent US Patents
11/16/2011
7,833,623
Modified slush moldable TPU for instrument panels with seamless airbag deployment capability
Humphrey, Jr. and Drago of International Automotive Components, Michigan, have developed a vehicle instrument panel skin consisiting of a thermoplastic urethane elastomer and a propylene-ethylene copolymer formed by slush molding. The thermoplastic urethane elastomer includes a polyol, an organic diisocyanate, an optional chain extender, and an optional hindered amine light stabilizer and a benzotriazole ultraviolet stabilizing agent. (RDC 3/30/2011)
9/16/2008
7,425,294
Plastic skin forming process
Grimmer, Syphers and Moore have developed a quick slush molding technique for forming a skin consisting of preheating a light weight metal mold with infrared, casting the liquid onto the mold surface, cooling by water evaporated cooling and removing the article. (RDC 9/24/2010)
7/29/2008
7,405,257
Polyurethane resin-based material for slush molding
Fujibayashi of Sanyo Chemical Industries has developed a slush molding technique for molding materials to cloth for automotive interiors based on a hot melt polyurethane adhesive. (RDC 9/24/2010)