Patent US1514052A successfully refreshed from Google Patents.
US5352401A
Expired / Lapsed
US
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Process for producing elevated temperature dimensionally stable polyester articles with low gas permeability
Assignee: Curwood Arkansas Inc
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Filing: 1993-04-16
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Granted: 1994-10-04
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Expires: 2013-04-16
Abstract
Abstract The invention provides a process of manufacturing a shaped polyester article having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in2-24 hr-atm at a temperature of 23 DEG C. and at 100% relative humidity inside and 60% relative humidity outside, and an enthalpy of recrystallization of from about 0 to about -2.1 cal/g, as well as a linear dimensional shrinkage between about 0% and 6% when heated from about -60 DEG C. to about 200 DEG C. The crystalline polyester articles are useful as containers for microwavable, ovenable and/or frozen foods, and have good gas barrier properties, and post-mold dimensional stability from about -60 DEG C. to about 200 DEG C.
Inventors
- 👤 Edward J. Dalgewicz, III
- 👤 Richard A. Freundlich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:48
CPC Classifications
B; B29; B29C; B29C49/00; B29C49/0005; B65; B65D; B65D81/00; B65D81/34; C; C08; C08G; C08G63/00; C08G63/88; C08L; C08L67/00; C08L67/02; B29C49/42; B29C49/64; B29C49/6604; B29C49/6605; B29C71/00; B29C71/0063; B29K; B29K2067/00; B29K2995/00; B29K2995/0012; B29K2995/0017; B29K2995/0037; B29K2995/004; B29K2995/0041; B29K2995/0065; B29K2995/0067; B65D81/3446; B65D81/3453; C08L101/00; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/131; Y10T428/1317; Y10T428/1321; Y10T428/1328; Y10T428/1352; Y10T428/1397; Y10T428/31504; Y10T428/31786
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
213 words
A process for producing a shaped polyester article comprising the steps: (a) heating a composition consisting essentially of a substantially non-oriented crystallizable thermoplastic polyethylene terephthalate homopolymer to a completely or substantially completely amorphous state; (b) maintaining the composition heated in step (a) at a temperature above the peak crystallization rate temperature of said crystallizable polyethylene terephthalate homopolymer, while simultaneously contacting said composition with a surface which imparts shape to said composition, said surface being at or above the peak crystallization rate temperature from melt for said polyethylene terephthalate homopolymer; (c) maintaining the contact between said composition and said surface, at the surface temperature set forth in step (b), for about 20 seconds to about 5 minutes to provide a crystalline composition having an enthalpy of recrystallization of about 0 to about -2.1 calories per gram as measured by differential scanning calorimetry; (d) cooling the crystalline composition provided by step (c) at a rate of from between about 5° C. to about 80° C. per minute, for a time sufficient to provide a shaped article comprising said polyethylene terephthalate homopolymer, with said shaped article having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in 2 -24 hrs-atm at 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 2
Dependent Claim
213 words
A process for producing a shaped polyester article comprising the steps: (a) heating a composition consisting essentially of a substantially non-oriented crystallizable thermoplastic polyethylene terephthalate homopolymer to a completely or substantially completely amorphous state; (b) maintaining the composition heated in step (a) at a temperature above the peak crystallization rate temperature of said crystallizable polyethylene terephthalate homopolymer, while simultaneously contacting said composition with a surface which imparts shape to said composition, said surface being at or above the peak crystallization rate temperature from melt for said polyethylene terephthalate homopolymer; (c) maintaining the contact between said composition and said surface, at the surface temperature set forth in step (b), for about 20 seconds to about 5 minutes to provide a crystalline composition having an enthalpy of recrystallization of about 0 to about -2.1 calories per gram as measured by differential scanning calorimetry; (d) cooling the crystalline composition provided by step (c) at a rate of from between about 5° C. to about 80° C. per minute, for a time sufficient to provide a shaped article comprising said polyethylene terephthalate homopolymer, with said shaped article having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in 2 -24 hrs-atm at 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 3
Dependent Claim
30 words
The process as set forth in claim 1, step (a) comprising heating said composition to a temperature greater than the crystallization onset temperature from melt of said polyethylene terephthalate homopolymer.
Claim 4
Dependent Claim
24 words
The process as set forth in claim 2, step (a) comprising heating said composition to from between about 500° F. to about 580° F.
Claim 5
Dependent Claim
26 words
The process as set forth in claim 1, wherein in step (b) said surface is at the peak crystallization rate temperature of said polyethylene terephthalate homopolymer.
Claim 6
Dependent Claim
21 words
The process as set forth in claim 1, wherein in step (b) said surface is the shaping surface of a mold.
Claim 7
Dependent Claim
30 words
The process as set forth in claim 1, wherein in step (c) contact is maintained between said surface and said polyester for from about 20 seconds to about 1 minute.
Claim 8
Dependent Claim
30 words
The process as set forth in claim 6, wherein in step (c) contact is maintained between said surface and said polyester for from about 20 seconds to about 40 seconds.
Claim 9
Dependent Claim
36 words
The process as set forth in claim 1, wherein in step (d) the the heat of recrystallization of said article is from about 0 to about -1.5 calories per gram as measured by differential scanning calorimetry.
Claim 10
Dependent Claim
35 words
The process as set forth in claim 8, wherein in step (d) the heat of recrystallization of said article is from about 0 to about -1.0 calories per gram as measured by differential scanning calorimetry.
Claim 11
Dependent Claim
32 words
The process as set forth in claim 1, step (d) comprising cooling said crystalline composition at a rate of between from about 5° C. per minute to about 50° C. per minute.
Claim 12
Dependent Claim
32 words
The process as set forth in claim 10, step (d) comprising cooling said crystalline composition at a rate of between from about 15° C. per minute to about 20° C. per minute.
Claim 13
Dependent Claim
27 words
The process as set forth in claim 1, wherein in step (d) said shaped article is microwavable, and ovenable up to a temperature of about 200° C.
Claim 14
Dependent Claim
21 words
The process as set forth in claim 12, wherein in step (d) said shaped article is ovenable and microwaveable food container.
Claim 15
Dependent Claim
26 words
The process as set forth in claim 13, wherein in step (d) said food container is a tray, box, pouch, packet or bottle, jar or cup.
Claim 16
Dependent Claim
19 words
The process as set forth in claim 1, wherein in step (d) said shaped article is a liquid container.
Claim 17
Dependent Claim
21 words
The process as set forth in claim 15, wherein in step (d) said liquid container is a bottle, jar or cup.
Claim 18
Dependent Claim
42 words
The process as set forth in claim 1, wherein in step (d) said oxygen permeability being from about about 0.2 to about 4 cc-mil/100 in 2 -24 hrs-atm at 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 19
Dependent Claim
41 words
The process as set forth in claim 17, wherein in step (d) said oxygen permeability being from about 0.2 to about 3 cc-mil/100 in 2 -24 hrs-atm at 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 20
Dependent Claim
41 words
The process as set forth in claim 18, wherein in step (d) said oxygen permeability being from about 0.2 to about 2 cc-mil/100 in 2 -24 hrs-atm at 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 21
Dependent Claim
41 words
The process as set forth in claim 19, wherein in step (d) said oxygen permeability being from about 0.2 to about 1 cc-mil/100 in 2 -24 hrs-atm at 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 22
Dependent Claim
36 words
The process as set forth in claim 1, wherein in step (d) said article having a linear dimensional shrinkage of between about 0% and about 6% when heated from about -60° C. to about 200° C.
Claim 23
Dependent Claim
36 words
The process as set forth in claim 21, wherein in step (d) said article having a linear dimensional shrinkage of between about 0% and about 3% when heated from about -60° C. to about 200° C.
Claim 24
Dependent Claim
199 words
A process for producing a shaped article comprising the steps: (a) heating a substantially non-oriented thermoplastic, crystallizable polyethylene terephthalate homopolymer to a completely or substantially completely amorphous state; (b) maintaining the polyethylene terephthalate heated in step (a) at a temperature above the peak crystallization rate temperature of said polyethylene terephthalate, while simultaneously contacting said polyethylene terephthalate with a surface which imparts shape to said composition, said surface being at or above the peak crystallization rate temperature for said polyethylene terephthalate; (c) maintaining the contact between said polyethylene terephthalate and said surface for from about 20 seconds to about 5 minutes to provide a crystalline polyethylene terephthalate having an enthalpy of recrystallization of about 0 to about -2.1 calories per gram as measured by differential scanning calorimetry; (d) cooling the crystalline polyethylene terephthalate provided by step (c) at a rate of from between about 5° C. to about 80° C. per minute, for a time sufficient to provide a shaped article comprising said polyethylene terephthalate, with said shaped article having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in 2 -24 hrs-atm at about 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 25
Dependent Claim
199 words
A process for producing a shaped article comprising the steps: (a) heating a substantially non-oriented thermoplastic, crystallizable polyethylene terephthalate homopolymer to a completely or substantially completely amorphous state; (b) maintaining the polyethylene terephthalate heated in step (a) at a temperature above the peak crystallization rate temperature of said polyethylene terephthalate, while simultaneously contacting said polyethylene terephthalate with a surface which imparts shape to said composition, said surface being at or above the peak crystallization rate temperature for said polyethylene terephthalate; (c) maintaining the contact between said polyethylene terephthalate and said surface for from about 20 seconds to about 5 minutes to provide a crystalline polyethylene terephthalate having an enthalpy of recrystallization of about 0 to about -2.1 calories per gram as measured by differential scanning calorimetry; (d) cooling the crystalline polyethylene terephthalate provided by step (c) at a rate of from between about 5° C. to about 80° C. per minute, for a time sufficient to provide a shaped article comprising said polyethylene terephthalate, with said shaped article having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in 2 -24 hrs-atm at about 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 26
Dependent Claim
196 words
A process for producing a shaped article comprising the steps: (a) heating a substantially non-oriented thermoplastic, crystallizable polyethylene terephthalate to a completely or substantially completely amorphous state; (b) maintaining the polyethylene terephthalate heated in step (a) at a temperature above the peak crystallization rate temperature of said polyethylene terephthalate, while simultaneously contacting said polyethylene terephthalate with a surface which imparts shape to said competition, said surface being at the peak crystallization rate temperature for said polyethylene terephthalate; (c) maintaining the contact between said polyethylene terephthalate and said surface for from about 20 seconds to about 5 minutes to provide a crystalline polyethylene terephthalate having an enthalpy of recrystallization of about 0 to about -2.1 calories per gram as measured by differential scanning calorimetry; (d) cooling the crystalline polyethylene terephthalate provided by step (c) at a rate of from between about 5° C. to about 80° C. per minute, for a time sufficient to provide a shaped article comprising said polyethylene terephthalate, with said shaped article having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in 2 -24 hrs-atm at about 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 27
Dependent Claim
196 words
A process for producing a shaped article comprising the steps: (a) heating a substantially non-oriented thermoplastic, crystallizable polyethylene terephthalate to a completely or substantially completely amorphous state; (b) maintaining the polyethylene terephthalate heated in step (a) at a temperature above the peak crystallization rate temperature of said polyethylene terephthalate, while simultaneously contacting said polyethylene terephthalate with a surface which imparts shape to said competition, said surface being at the peak crystallization rate temperature for said polyethylene terephthalate; (c) maintaining the contact between said polyethylene terephthalate and said surface for from about 20 seconds to about 5 minutes to provide a crystalline polyethylene terephthalate having an enthalpy of recrystallization of about 0 to about -2.1 calories per gram as measured by differential scanning calorimetry; (d) cooling the crystalline polyethylene terephthalate provided by step (c) at a rate of from between about 5° C. to about 80° C. per minute, for a time sufficient to provide a shaped article comprising said polyethylene terephthalate, with said shaped article having an oxygen permeability of from about 0.2 to about 4.9 cc-mil/100 in 2 -24 hrs-atm at about 23° C. and at 100% relative humidity inside and 60% relative humidity outside.
Claim 28
Dependent Claim
37 words
The process as set forth in any one of claims 1 to 22 wherein the composition also contains at least one additive selected from the group of nucleants, colorants, heat stabilizers, mold release agents and trimming agents.
Claim 29
Dependent Claim
32 words
The process as set forth in claim 23 wherein step (a) also includes at least one additive selected from the group of nucleants, colorants, heat stabilizers, mold release agents, and trimming agents.
Claim 30
Dependent Claim
32 words
The process as set forth in claim 24 wherein step (a) also includes at least one additive selected from the group of nucleants, colorants, heat stabilizers, mold release agents and trimming agents.
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