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US 2026/0226245 A1Published application
Methods of thermoforming cellulose ester foamed articles
AssigneeEastman Chemical Company
InventorsMichael Eugene Donelson, Rahul Shankar, Goliath Beniah, Stephanie Kay Clendennen, Gaurav Amarpuri, Nicola Anne Herndon, James Collins Maine, Madeleine Kate Miller
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Abstract
Methods of thermoforming foamed cellulose ester sheets into foamed trays. The methods, and compositions used therein, provide for foamed trays having desirable skin integrity after thermoforming. One or more high heat capacity additives and/or melt strength enhancers may be used to provide improved skin integrity at higher thermoforming draw ratios.
Claims19
A method of forming a foamed article, the method comprising:
- (a) producing a foamed sheet from a cellulose ester composition, wherein the cellulose ester composition comprises:
- (i) a cellulose acetate, where the cellulose acetate has a degree of substitution for acetyl substituents (“DSAc”) of from 2.2-2.8,
- ii) 10 to 25 wt % of a plasticizer, wherein the plasticizer is triacetin, poly (ethylene glycol with a molecular weight of from 200-600, triethyl citrate, or a combination thereof, and
- (iii) 0.3 to 8 wt % of a blowing agent,
- each based on the total weight of the composition;
- and
- (b) thermoforming the foamed sheet in a mold having a footprint area (X) and a surface area that is less than 1.9X, thereby forming the foamed article,
- wherein the thermoforming heats the foamed sheet to a surface temperature of from 170° C. to 205° C.,
- wherein when the foamed sheet is formed into a foamed tray and the foamed tray is filled with water and allowed to equilibrate at room temperature for 18 hours, the foam tray has a weight gain of less than 15% according to the Water Absorption Test described in the specification.
6 more elements
Dependencies are inferred from the claim text.