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US 5,514,315 AGranted
Polypropylene spa shell manufacturing method
AssigneeWatkins Manufacturing Corporation
InventorsJeffrey K. Watkins, Walter R. Cumiskey, Victor B. McCarthy
Life of this patent
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Abstract
A process of forming a spa shell by selecting a coextruded polypropylene sheet, selectively heating the sheet, vacuum forming the heated sheet on a deep draw female mold to form a molded spa shell shape, flame treating one surface of the molded shell shape, heating the flame-treated surface, and applying a layer of polyurethane foam to the heated surface.
Claims24
A process for forming a spa shell from a coextruded polypropylene sheet comprising the steps of:
- heating said polypropylene sheet to a base temperature and selectively applying additional heat to preselected areas of said sheet to form a heated polypropylene sheet;
- deep drawing said heated polypropylene sheet on a female mold to form a molded spa shape;
- modifying one surface of said shape to receive and attach to a polyurethane layer;
- heating said surface;
- and
- applying a polyurethane layer to said surface.
3 more elements
A process for forming a tub from a coextruded polypropylene sheet comprising the steps of:
- heating said polypropylene sheet to a base temperature and selectively applying additional heat to preselected areas of said sheet to form a heated polypropylene sheet;
- deep drawing said heated polypropylene sheet on a female mold to form a molded tub shape;
- modifying one surface of said tub shape to receive and attach to a polyurethane layer;
- heating said surface;
- and
- applying a polyurethane layer to said surface.
3 more elements
Dependencies are inferred from the claim text.