Thermoformed polypropylene mineral-filled microwaveable containers having food contact compatible olfactory properties and process for their manufacture
AssigneeFort James Corporation
InventorsDonald C. McCarthy, Ronald L. Cochran, II, Mark B. Littlejohn, Cristian M. Neculescu, Robert Patterson, Anthony J. Swiontek
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Abstract
Low-odor microwaveable mineral-filled polypropylene food contact articles are disclosed. The articles are prepared by low temperature processing and typically include odor-suppressing basic organic or inorganic compounds. Preferably, the articles are substantially free from C8 and C9 organic ketones associated with undesirable odors. Further improvements to the articles include crack-resistant embodiments with synergistic amounts of polyethylene and titanium dioxide.
Claims48
A method of preparing a microwaveable, mineral-filled polypropylene food container comprising:
- (a) preparing a melt-compounded composition comprising from about 40 to about 90 percent by weight of a propylene polymer, from about 10 to about 50 percent by weight of a primary mineral filler and an effective odor-reducing amount of a basic organic or basic inorganic compound, said melt-compounded composition exhibiting an odor index of less than 0.75;
- (b) extruding said melt-compounded composition into sheet form;
- and
- (c) forming said food container from said sheet wherein said basic organic or inorganic compound is operative to reduce undesirable odors in said melt-compounded composition to the aforesaid odor index value of 0.75 or less, and wherein said melt-compounded composition is produced at a process melt temperature of less than about 425° F.
A method of preparing a microwaveable, mineral-filled polypropylene food container comprising:
- (a) preparing a melt compounded composition comprising from about 40 to about 90 percent by weight of a propylene polymer, from about 10 to about 50 percent by weight of a primary mineral-filler and an effective odor-reducing amount of a basic organic or inorganic compound, said melt-compounded composition exhibiting an odor index of less than 0.75;
- (b) extruding said melt-compounded composition into sheet form;
- and
- (c) forming said food container from said sheet wherein said basic organic or inorganic compound is operative to reduce undesirable odors in said melt-compounded composition to the aforesaid odor index value of 0.75 or less,
- wherein said container is formed, or thermoformed by application of pressure, by application of vacuum, or by a combination of vacuum and pressure, into the shape of said container;
- said container exhibiting a melting point of no less than about 250° F., said container being dimensionally stable and resistant to grease, sugar and water at temperatures up to at least 220° F. and of sufficient toughness to be resistant to cutting by a serrated polystyrene flatware and wherein said container has at least one micronodular food contact surface.
A method of preparing a microwaveable, mineral-filled polypropylene food container comprising:
- (a) preparing a melt-compounded composition comprising from about 40 to about 90 percent by weight of a propylene polymer and from about 10 to about 50 percent by weight of a primary mineral filler and optionally an effective amount of an odor-reducing compound;
- said melt-compounded composition exhibiting a relative aroma index, relative to a 30 weight percent mica composition of less than 0.75;
- (b) extruding said melt-compounded composition into sheet form;
- and
- (c) forming said food container from said sheet;
- wherein said melt-compounded composition is produced at a process melt temperature of less than about 425° F.
A method of preparing a microwaveable, mineral-filled polypropylene food container comprising:
- (a) preparing a melt-compounded composition comprising from about 40 to about 90 percent by weight of a propylene polymer, from about 10 to about 50 percent by weight of a primary mineral filler and optionally an effective odor-reducing amount of a basic or optionally acidic organic or inorganic compound;
- (b) extruding said melt-compounded composition into sheet form;
- and
- (c) forming said food contact article from said sheet, wherein the melt-compounded composition exhibits a relative aroma Index value of 0.75 or less;
- wherein said melt-compounded composition is produced at a process melt temperature of less than about 425° F.
Dependencies are inferred from the claim text.