Patent US4467052A successfully refreshed from Google Patents.
US4467052A
Expired / Lapsed
US
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Tray for packaging food products
Assignee: STERLING PACKAGING Corp A CORP OF TEXAS
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Filing: 1982-03-18
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Granted: 1984-08-21
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Expires: 2002-03-18
Abstract
Abstract A plastic tray for packaging food products is disclosed. The tray has a preferred composition of about 85 percent polypropylene, 15 percent impact modifier or copolymer, 1 percent nucleating agent, and 1 percent density reduction agents. A method of manufacturing a plastic tray of packaging food products is disclosed. The method includes the steps of mixing the polypropylene, impact modifier, nucleating agent and density reduction agents together, heating the mixture at 450° F. to 550° F. under a pressure of about 300 p.s.i., injecting the heated mixture into a mold, and cooling the mixture.
Inventors
- 👤 Robert Barnwell
- 👤 David R. Frye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:19
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/0066; C08J9/0061; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; Y; Y10; Y10S; Y10S264/00; Y10S264/05; Y10S264/83; Y10S521/00; Y10S521/908
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
149 words
An injection moldable plastic tray composition for packaging meat products and having satisfactory resistance to breakage in a food processing application, comprising in a blended combination: a polypropylene having a melt flow rate of 25 to 35 grams per ten minutes to provide a base material for a plastic tray, where the polypropylene comprises about 85 percent of the tray; a styrene-butadiene copolymer impact modifier to provide toughness in the tray, where the styrene-butadiene copolymer comprises about 15 percent of the tray; a nucleating agent including a mixture of silicon dioxide and aluminum oxide to promote crystal formation during manufacture of the tray and to promote flatness of the tray, where the nucleating agent comprises less than 1 percent of the tray; and, density reduction agents including a mixture of anhydrous citric acid and sodium carbonate, where the density reduction agents comprise less than 1 percent of the tray.
Claim 2
Dependent Claim
149 words
An injection moldable plastic tray composition for packaging meat products and having satisfactory resistance to breakage in a food processing application, comprising in a blended combination: a polypropylene having a melt flow rate of 25 to 35 grams per ten minutes to provide a base material for a plastic tray, where the polypropylene comprises about 85 percent of the tray; a styrene-butadiene copolymer impact modifier to provide toughness in the tray, where the styrene-butadiene copolymer comprises about 15 percent of the tray; a nucleating agent including a mixture of silicon dioxide and aluminum oxide to promote crystal formation during manufacture of the tray and to promote flatness of the tray, where the nucleating agent comprises less than 1 percent of the tray; and, density reduction agents including a mixture of anhydrous citric acid and sodium carbonate, where the density reduction agents comprise less than 1 percent of the tray.
Claim 3
Dependent Claim
138 words
A plastic tray for packaging food products, comprising: a polypropylene having a melt flow rate of 25 to 35 grams per ten minutes to provide a base material for a plastic tray, where the polypropylene comprises 82 to 88 percent of the tray; an impact modifier to provide toughness, where the impact modifier comprises 12 to 18 percent of the tray; a mucleating agent including a mixture of silicon dioxide and aluminum oxide to promote crystal formation during manufacture of the tray, where the nucleating agent comprises up to 10 percent of the tray and, to provide density reduction of the tray, anhydrous citric acid comprises up to 2 percent of the tray and a material selected from the group consisting of soda ash and sodium carbonate where said material comprises up to 2 percent of the tray.
Claim 4
Dependent Claim
138 words
A plastic tray for packaging food products, comprising: a polypropylene having a melt flow rate of 25 to 35 grams per ten minutes to provide a base material for a plastic tray, where the polypropylene comprises 82 to 88 percent of the tray; an impact modifier to provide toughness, where the impact modifier comprises 12 to 18 percent of the tray; a mucleating agent including a mixture of silicon dioxide and aluminum oxide to promote crystal formation during manufacture of the tray, where the nucleating agent comprises up to 10 percent of the tray and, to provide density reduction of the tray, anhydrous citric acid comprises up to 2 percent of the tray and a material selected from the group consisting of soda ash and sodium carbonate where said material comprises up to 2 percent of the tray.
Claim 5
Dependent Claim
15 words
The tray according to claim 2, wherein: the impact modifier comprises a styrene-butadiene block copolymer.
Claim 6
Dependent Claim
13 words
The tray according to claim 2, wherein: the impact modifier comprises a butyl-polymer.
References Cited (Backward Citations)
US2941964A
Cited
US2927904A
Cited
US3351569A
Cited
US3511787A
Cited
US3294868A
Cited
US3385804A
Cited
US4029612A
Cited
US3962154A
Cited
US4098941A
Cited
US4168341A
Cited
US4205114A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-21 | 1988-02-20 | 1988-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-21 | 1992-02-20 | 1992-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-21 | 1996-02-20 | 1996-08-21 | $7700.00 | Window Closed / Lapsed |