US4582665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making poly(ethylene terephthalate) articles
Assignee: Graham Packaging Plastic Products Inc
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Filing: 1984-10-12
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Granted: 1986-04-15
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Expires: 2004-10-12
Abstract
Abstract Disclosed is a process of making an oriented and heat set thermoformed hollow article of poly(ethylene terephthalate) so that the sidewalls of the articles resulting from the process have a density over 1.391 cc./gm. and an onset-of-shrinkage temperature over 105° C. In the process, a sheet preheated to a temperature suitable for orientation is biaxially stretch thermoformed and then while the hollow article walls are still in contact with the mold walls, the article is raised to a higher heat setting temperature in the range of about 220-250° C. thus heat setting the article, and while the article is still under restraint resisting shrinkage, quenching the sidewalls of the article to a temperature that will provide a shrinkage of less than about 5% by volume and the above onset-of-shrinkage temperature of at least about 105° C.
Inventors
- 👤 Saleh A. Jabarin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:51
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/26; B29C51/42; B29C51/426; B29C51/002; B29K; B29K2067/00; B29K2995/00; B29K2995/0012; B29K2995/0017
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
192 words
A method for making a high density, partially crystalline, oriented, heat set, thermoformed polyethylene terephthalate hollow container, the container having a body with oriented sidewalls, the method comprising the steps of: A. providing by thermoforming a hollow container with oriented sidewalls; B. while the container is under restraint to maintain its essential size and shape, increasing the density of the oriented sidewalls to at least about 1.391 g/cc by heating the sidewalls to a heat setting temperature equivalent to a temperature of about 220° C. to 250° C. to provide the density of at least about 1.391 g/cc; and C. quenching the sidewalls while under a shrinkage reducing restraint to provide the article with a shrinkage of less than about 5% of the volume and an onset-of-shrinkage temperature of at least about 105° C., the quenching being done at a temperature equivalent to that of about room temperature to 180° C. at a high heat setting temperature of about 240° C., about 85° C. to 160° C. for a heat setting temperature of about 230° C., and about 120° C. to 150° C. for a heat setting temperature of about 220° C.
Claim 2
Independent Claim
192 words
A method for making a high density, partially crystalline, oriented, heat set, thermoformed polyethylene terephthalate hollow container, the container having a body with oriented sidewalls, the method comprising the steps of: A. providing by thermoforming a hollow container with oriented sidewalls; B. while the container is under restraint to maintain its essential size and shape, increasing the density of the oriented sidewalls to at least about 1.391 g/cc by heating the sidewalls to a heat setting temperature equivalent to a temperature of about 220° C. to 250° C. to provide the density of at least about 1.391 g/cc; and C. quenching the sidewalls while under a shrinkage reducing restraint to provide the article with a shrinkage of less than about 5% of the volume and an onset-of-shrinkage temperature of at least about 105° C., the quenching being done at a temperature equivalent to that of about room temperature to 180° C. at a high heat setting temperature of about 240° C., about 85° C. to 160° C. for a heat setting temperature of about 230° C., and about 120° C. to 150° C. for a heat setting temperature of about 220° C.
Claim 3
Dependent Claim
30 words
A method as defined in claim 1 in which the heat setting temperature is about 225° to 250° C. and the increased density of the sidewalls is about 1.393 g/cc.
Claim 4
Dependent Claim
25 words
A method as defined in claim 1 in which the heat setting temperature is about 230° C. and the quenching temperature is about 100° C.
Claim 5
Dependent Claim
208 words
A process which comprises A. biaxially orienting the body of a poly(ethylene terephthalate) hollow article by biaxially stretch thermoforming poly(ethylene terephthalate) sheet preheated to a suitable orientation temperature range to form a hollow biaxially oriented hollow article; B. while the container is under restraint to maintain its essential size and shape, increasing the density of the oriented sidewalls to at least about 1.391 g/cc by heating the sidewalls to a heat setting temperature equivalent to a temperature of about 220° C. to 250° C. to provide the density of at least about 1.391 g/cc; C. quenching the sidewalls while under a shrinkage reducing restraint to provide the article with a shrinkage of less than about 5% of the volume and an onset-of-shrinkage temperature of at least about 105° C., the quenching being done at a temperature equivalent to that of about room temperature to 180° C. at a high heat setting temperature of about 240° C., about 85° C. to 160° C. for a heat setting temperature of about 230° C., and about 120° C. to 150° C. for a heat setting temperature of about 220° C.; D. thereafter removing said restraint from the hollow article; and E. effecting further cooling of the hollow article without said restraint.
Claim 6
Dependent Claim
208 words
A process which comprises A. biaxially orienting the body of a poly(ethylene terephthalate) hollow article by biaxially stretch thermoforming poly(ethylene terephthalate) sheet preheated to a suitable orientation temperature range to form a hollow biaxially oriented hollow article; B. while the container is under restraint to maintain its essential size and shape, increasing the density of the oriented sidewalls to at least about 1.391 g/cc by heating the sidewalls to a heat setting temperature equivalent to a temperature of about 220° C. to 250° C. to provide the density of at least about 1.391 g/cc; C. quenching the sidewalls while under a shrinkage reducing restraint to provide the article with a shrinkage of less than about 5% of the volume and an onset-of-shrinkage temperature of at least about 105° C., the quenching being done at a temperature equivalent to that of about room temperature to 180° C. at a high heat setting temperature of about 240° C., about 85° C. to 160° C. for a heat setting temperature of about 230° C., and about 120° C. to 150° C. for a heat setting temperature of about 220° C.; D. thereafter removing said restraint from the hollow article; and E. effecting further cooling of the hollow article without said restraint.
Claim 7
Dependent Claim
33 words
A process of claim 4 wherein said second temperature range is achieved at least in part by contacting said hollow article with a hot mold wall which is at said second temperature range.
Claim 8
Dependent Claim
87 words
A process as defined in claim 4 for forming a biaxially oriented and heat set hollow article from poly(ethylene terephthalate) sheet which comprises biaxially stretch thermoforming said sheet which has been preheated to an orientation temperature range to form a final hollow article against a male or a female mold wall surface, and heat setting while said article is under stress or restraint preventing shrinkage, by contacting said article with said mold wall which is at a higher heat setting temperature of about 220° to 250° C.
Claim 9
Dependent Claim
22 words
A process of claim 4 wherein said quenching is at about 100° C. and the heat setting temperature is about 230° C.
Claim 10
Dependent Claim
31 words
A process of claim 4 wherein said mold wall surface is at said temperature range of about 220° to 250° C. when said hollow article wall first contacts it during thermoforming.
Claim 11
Independent Claim
256 words
A method of making a high density, partially crystalline, biaxially oriented hollow poly(ethylene terephthalate) plastic article from a sheet of said plastic by stretch thermoforming comprising A. heating a sheet of said plastic to a first temperature range, which first temperature range is conducive to orientation during stretch thermoforming thereof; B. while said sheet is still at said first temperature range stretch thermoforming said sheet into contact and conformance with either a male or female mold wall surface to make a hollow article, said stretch thermoforming under the resulting strain conditions resulting in biaxial orientation and concomitant partial crystallization of said poly(ethylene terephthalate); and then C. while the container is under restraint to maintain its essential size and shape, increasing the density of the oriented sidewalls to at least about 1.391 g/cc by heating the sidewalls to a heat setting temperature equivalent to a temperature of about 220° C. to 250° C. to provide the density of at least about 1.391 g/cc; and D. quenching the sidewalls while under a shrinkage reducing restraint to provide the article with a shrinkage of less than about 5% of the volume and an onset-of-shrinkage temperature of at least about 105° C., the quenching being done at a temperature equivalent to that of about room temperature to 180° C. at a high heat setting temperature of about 240° C., about 85° C. to 160° C. for a heat setting temperature of about 230° C., and about 120° C. to 150° C. for a heat setting temperature of about 220° C.
Claim 12
Independent Claim
256 words
A method of making a high density, partially crystalline, biaxially oriented hollow poly(ethylene terephthalate) plastic article from a sheet of said plastic by stretch thermoforming comprising A. heating a sheet of said plastic to a first temperature range, which first temperature range is conducive to orientation during stretch thermoforming thereof; B. while said sheet is still at said first temperature range stretch thermoforming said sheet into contact and conformance with either a male or female mold wall surface to make a hollow article, said stretch thermoforming under the resulting strain conditions resulting in biaxial orientation and concomitant partial crystallization of said poly(ethylene terephthalate); and then C. while the container is under restraint to maintain its essential size and shape, increasing the density of the oriented sidewalls to at least about 1.391 g/cc by heating the sidewalls to a heat setting temperature equivalent to a temperature of about 220° C. to 250° C. to provide the density of at least about 1.391 g/cc; and D. quenching the sidewalls while under a shrinkage reducing restraint to provide the article with a shrinkage of less than about 5% of the volume and an onset-of-shrinkage temperature of at least about 105° C., the quenching being done at a temperature equivalent to that of about room temperature to 180° C. at a high heat setting temperature of about 240° C., about 85° C. to 160° C. for a heat setting temperature of about 230° C., and about 120° C. to 150° C. for a heat setting temperature of about 220° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |