Patent ID: 7842226
Filing Date: 2010-11-30
Classification: B29C,B29K

Abstract:
1. A method of preparing a molded article comprising: (a) providing a mold apparatus comprising, (b) positioning said first mold portion and said frame relative to each other such that the upper surface of said frame is located above said perimeter edge; (c) positioning said clamp member of each sheet retainer in an open position so as to provide access to said clamp interior; (d) forming, from at least one thermoplastic composition, a heated thermoplastic sheet having a temperature that allows said heated thermoplastic sheet to be thermoformable, said heated thermoplastic sheet having a first surface and a second surface; (e) contacting a first portion of said second surface of said heated thermoplastic sheet with the clamp interior of at least one sheet retainer; (f) positioning said clamp member of said sheet retainer in a closed position so as to clamp and retain said first portion of said heated thermoplastic sheet within said clamp interior; (g) positioning said first mold portion and said frame relative to each other so as to contact a second portion of the second surface of said heated thermoplastic sheet with at least a portion of the interior mold surface of said first mold portion; (h) moving laterally at least one sheet retainer to a lateral position selected from the group consisting of towards said perimeter edge, away from said perimeter edge, and combinations thereof, (i) drawing reduced pressure through said plurality of perforations of said interior mold surface of said first mold portion, such that said second portion of said second surface of said heated thermoplastic sheet substantially matches said contour of said interior mold surface of said first mold portion; (j) cooling said heated thermoplastic sheet thereby forming a shaped thermoplastic sheet that retains said contour of said interior mold surface of said first mold portion; and (k) removing said shaped thermoplastic sheet from said first mold portion, wherein said shaped thermoplastic sheet is said molded article.