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US 2014/0370218 A1Published application
Foamed articles with deep undercuts
AssigneeEastman Chemical Company
InventorGary Stuart Hawkins
Life of this patent
Estimating the term…
Abstract
The present invention relates generally to thermoformed articles having one or more deep undercuts and to processes for making such articles. The undercuts produced using the process described herein exhibit superior properties compared to undercuts present in conventional articles. The thermoformed articles can be produced using a foamed polyester-containing material which facilitates the production of undercuts exhibiting superior properties.
Claims23
A thermoformed article comprising:
- a wall;
- and
- an undercut projecting from said wall,
- wherein said undercut presents an apex, wherein said undercut has a maximum undercut draw depth measured at said apex and an average undercut thickness measured at said apex, wherein the ratio of said maximum undercut draw depth to said average undercut thickness is at least 0.5:1,
- wherein at least a portion of said undercut and at least a portion of said wall are formed of a common layer of a polyester-containing material having a specific gravity of less than 1.
2 more elements
A thermoformed article comprising:
- a pair of spaced-apart walls defining a cavity therebetween;
- and
- an undercut projecting from one of said walls,
- wherein said undercut presents an apex, wherein said undercut has a maximum undercut draw depth measured at said apex and a cross-sectional undercut area measured at said apex, wherein said maximum undercut draw depth is at least 15 millimeters,
- wherein said cavity has a cross-sectional cavity area,
- wherein the ratio of said cross-sectional cavity area to said cross-sectional undercut area is at least 1:1 and not more than 100:1,
- wherein at least a portion of said undercut and at least a portion of said wall from which said undercut projects are formed of a common layer of a polyester-containing material having a void volume of at least 5 percent.
4 more elements
A method of making a thermoformed article, said method comprising:
- (a) thermoforming a sheet into a thermoformed item by forcing said sheet into contact with a shaped surface of a mold while said sheet is maintained at an elevated thermoforming temperature, wherein said shaped surface comprises an undercut-forming surface for providing said thermoformed item with an undercut having a maximum undercut draw depth of at least 10 mm;
- (b) cooling said thermoformed item below said thermoforming temperature to thereby provide a cooled thermoformed item;
- and
- (c) separating said cooled thermoformed item from contact with said mold by moving said cooled thermoformed item and/or said mold in a pull direction without having first retracted said undercut-forming surface of said mold from said undercut in a direction other than said pull direction.
1 more element
Dependencies are inferred from the claim text.