US4560520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single-layer elastic tubular film of polyamide used for packaging paste substances and a process for the production of such film
Assignee: Naturin Werk Becker and Co
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Filing: 1984-06-13
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Granted: 1985-12-24
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Expires: 2004-06-13
Abstract
Abstract The present invention relates to a tubular film used for packing foodstuffs in paste form, this tubular film being polyamide that can absorb at least 5% water, and which at an internal pressure between 0 and 0.6 bar permits substantially reversible deformation and which has a matt appearance. The present invention also relates to a process for the production of this tubular film by multiaxial stretching of the primary tube with stretch ratios of at least 1:2.3 in the longitudinal direction and at least 1:2.5 in the transverse direction, and total thermal fixing of the stretched tube during controlled shrinkage. In addition, the invention describes a boiled or cooked sausage as well as a soft cheese, these being packed in a tubular film according to the invention.
Inventors
- 👤 Gayyur Erk
- 👤 Rudi Korlatzki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:55
CPC Classifications
A; A22; A22C; A22C13/00; A22C13/0013; B; B29; B29C; B29C55/00; B29C55/28; A22C2013/005; A22C2013/0059; A22C2013/0063; B29C71/00; B29K; B29K2077/00; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1324
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
122 words
A process for the production of a tubular film consisting of at least a polyamide that can absorb at least 0.5% of its weight in water up to saturation, which tubular film is used for packaging and casing foodstuffs in paste form, especially footstuffs that are packed when hot or are subject to heat-treatment after packaging, comprising the steps of: extruding a primary tube of polyamide and simultaneously multi-axially stretching the primary tube; and subjecting the extruded and multi-axially stretched primary tube to a controlled shrinkage by at least 15% and at most 40% in the transverse and the longitudinal direction in relation to its transverse and longitudinal dimension after stretching, at temperatures above 90° C., thereby thermally fixing the primary tube.
Claim 2
Dependent Claim
122 words
A process for the production of a tubular film consisting of at least a polyamide that can absorb at least 0.5% of its weight in water up to saturation, which tubular film is used for packaging and casing foodstuffs in paste form, especially footstuffs that are packed when hot or are subject to heat-treatment after packaging, comprising the steps of: extruding a primary tube of polyamide and simultaneously multi-axially stretching the primary tube; and subjecting the extruded and multi-axially stretched primary tube to a controlled shrinkage by at least 15% and at most 40% in the transverse and the longitudinal direction in relation to its transverse and longitudinal dimension after stretching, at temperatures above 90° C., thereby thermally fixing the primary tube.
Claim 3
Dependent Claim
30 words
The process according to claim 1, wherein during the multiaxial stretching a longitudinal stretch ratio of 1:2.3 to 1:4, and a transverse stretch ratio of 1:2.5 to 1:4.5 is achieved.
Claim 4
Dependent Claim
14 words
A process according to claim 1, wherein thermal fixing is completed in one stage.
Claim 5
Dependent Claim
31 words
A process according to claim 1, wherein controlled shrinkage and complete thermal fixing is undertaken by thermal treatment of the tubular film for at least 20 and at most 240 seconds.
Claim 6
Dependent Claim
39 words
A process according to claim 1, wherein the thermal treatment is carried out using hot water, steam, or a heated polyvalent alcohol that contains at least 10% water, at temperatures of at least 90° and at most 150° C.
Claim 7
Dependent Claim
36 words
A process according to claim 1, wherein the thermal treatment is carried out using hot air, a heated inert gas, or IR irradiation at temperatures of not less than 180° C., and not above 320° C.
Claim 8
Dependent Claim
37 words
A process according to claim 1, wherein after the multiaxial stretching, thermal fixing is carried out initially during controlled shrinkage, the thermal fixing being completed in a separate stage while maintaining the dimensions achieved after the shrinking.
Claim 9
Dependent Claim
18 words
A process according to claim 7, wherein thermal fixing is completed at higher temperatures than the shrinkage temperatures.
Claim 10
Dependent Claim
33 words
A process according to claim 7, wherein controlled shrinkage is carried out in the presence of hot water or steam at a temperature of 90° to 100° C. for 20 to 240 seconds.
Claim 11
Dependent Claim
57 words
A process according to claim 7, wherein subsequent to the multiaxial stretching, the thermal fixing is completed by means of hot air, heated inert gas, or IR irradiation at temperatures of not less than 180° C. and not more than 320° C., for periods of not less than 3 seconds, and for a maximum of 240 seconds.
Claim 12
Dependent Claim
18 words
A process according to claim 1, wherein the tubular film has a minimum wall thickness of 38 μm.
References Cited (Backward Citations)
US3369911A
Cited
GB1387030A
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GB1461401A
Cited
US4061707A
Cited
US4243074A
Cited
US4303711A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-12-23 | 1989-06-24 | 1989-12-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-23 | 1993-06-24 | 1993-12-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-23 | 1997-06-24 | 1997-12-24 | $7700.00 | Window Closed / Lapsed |