US5023137A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyester composition which is particularly suitable for use in thermoforming dual-ovenable trays
Assignee: Corpus Christi Polymers LLC
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Filing: 1989-03-27
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Granted: 1991-06-11
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Expires: 2009-03-27
Abstract
Abstract This invention relates to a thermoplastic resin composition which is particularly suitable for use in thermoforming thin walled articles, such as dual-ovenable trays. Articles which are made utilizing this thermoplastic resin composition have improved low temperature impact strength. These thermoplastic resin compositions are comprised of (a) from about 92 to about 99 weight percent polyethylene terephthalate having an intrinsic viscosity of from at least about 0.7 dl/g; (b) from about 1 to about 8 weight percent of a polyethylene ionomer; and (c) optionally an effective amount of a heat stabilizer. The subject invention also deals with thermoforming such thermoplastic resin compositions into thin walled articles having a crystallinity within the range of about 10% to about 40%.
Inventors
- 👤 Richard R. Smith
- 👤 Walter F. Johnston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:48
CPC Classifications
C; C08; C08L; C08L67/00; C08L67/02; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1352; Y10T428/1397; Y10T428/31504; Y10T428/31786; Y10T428/31855
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
87 words
A thermoformed, non-oriented, heat set, thin walled article, comprising: (a) from about 92 to about 99 weight percent polyethylene terephthalate having an intrinsic viscosity of at least about 0.7 dl/g as measured in a 60:40 phenol/tetrachloroethane mixed solvent system at 30° C.; and (b) from about 1 to about 8 weight percent of a polyethylene ionomer having a melt flow index as measured using ASTM Method D-1238 of less than about 2 g/10 minutes; said article having a total crystallinity of from about 10% to about 40%.
Claim 2
Dependent Claim
87 words
A thermoformed, non-oriented, heat set, thin walled article, comprising: (a) from about 92 to about 99 weight percent polyethylene terephthalate having an intrinsic viscosity of at least about 0.7 dl/g as measured in a 60:40 phenol/tetrachloroethane mixed solvent system at 30° C.; and (b) from about 1 to about 8 weight percent of a polyethylene ionomer having a melt flow index as measured using ASTM Method D-1238 of less than about 2 g/10 minutes; said article having a total crystallinity of from about 10% to about 40%.
Claim 3
Dependent Claim
41 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 1 which is comprised of from about 94 weight percent to about 98.5 weight percent PET and from about 1.5 weight percent to about 6 weight percent polyethylene ionomer.
Claim 4
Dependent Claim
70 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 2 which is further comprised of an effective amount of a heat stabilizer, wherein the effective amount of heat stabilizer is within the range of about 0.005 percent by weight to about 2 percent by weight, and wherein the polyethylene terephthalate has an intrinsic viscosity which is within the range of about 0.8 dl/g to about 1.4 dl/g.
Claim 5
Dependent Claim
38 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 3 wherein said polyethylene ionomer has an impact strength as measured at 23° C. using ASTM Method D-1822S of at least about 1150 KJ/m 2 .
Claim 6
Dependent Claim
22 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 5 which has a crystallinity of between 15 and 40%.
Claim 7
Dependent Claim
47 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 5 wherein the polyethylene ionomer is a copolymer of ethylene and methacrylic acid which is from about 5% to about 90% neutralized with at least one metallic cation having a valence of 1 to 3.
Claim 8
Dependent Claim
29 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 6 wherein the polyethylene ionomer has a melt flow index of less than about 1.5 g/10 minutes
Claim 9
Dependent Claim
29 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 6 wherein the polyethylene ionomer has a melt flow index of less than about 1.2 g/10 minutes.
Claim 10
Dependent Claim
27 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 7 wherein the polyethylene ionomer is a terpolymer of ethylene, acrylic acid and sodium acrylate.
Claim 11
Dependent Claim
48 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 7 wherein the polyethylene ionomer is a polymer which contains from about 3 weight percent to about 20 weight percent α,β-ethylenically unsaturated carboxylic acids and from about 80 weight percent to about 97 weight percent ethylene.
Claim 12
Dependent Claim
27 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 2 wherein the polyethylene terephthalate has an intrinsic viscosity of at least about 0.9 dl/g.
Claim 13
Dependent Claim
34 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 2 wherein the polyethylene ionomer has an impact strength as measured at 23° C. of at least about 1200 KJ/m 2 .
Claim 14
Dependent Claim
21 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 6 wherein the polyethylene terephthalate is polyethylene terephthalate homopolymer.
Claim 15
Dependent Claim
30 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 6 wherein the article has a crystallinity which is within the range of about 25% to about 35%.
Claim 16
Dependent Claim
24 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 1 wherein said article is in the form of a dual-ovenable tray.
Claim 17
Dependent Claim
46 words
A thermoformed, non-oriented, heat set, thin walled article as specified in claim 6 wherein said article is comprised of from about 96 weight percent to about 98 weight percent polyethylene terephthalate and from about 2 weight percent to about 4 weight percent of the polyethylene ionomer.
References Cited (Backward Citations)
US4572852A
Cited
US4740377A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-10 | 1994-12-10 | 1995-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-10 | 1998-12-10 | 1999-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-10 | 2002-12-10 | 2003-06-11 | $7700.00 | Window Closed / Lapsed |