EP0062800A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Shrinkable polyamide film and process for its production
Assignee: Unitika Ltd
•
Filing: 1982-03-24
•
Granted: —
•
Expires: 2002-03-24
Abstract
Abstract A shrinkable polyamide film useful for wrapping hams, sausages, etc. The shrinkable film has a hydrothermal shrinking ratio of at least 30% in both MD and TD and a hydrothermal shrinkage stress of from 300 to 700 g/mm 2 . The film is produced by a process which comprises biaxially stretching a substantially amorphous film composed of a copolymer of 6,6-nylon/6-nylon in a weight ratio of from 5/95 to 25/75 at a temperature of not higher than 120°C and at a stretching ratio of at least 2.5 times in both MD and TD, and subjecting the stretched film to stress relaxation at a temperature of from the stretching temperature to 170°C, followed by winding it up. Further, a shrinkable film having an oxygen gas permeability of not more than 20 cc/m 2 .24 hrs. atm. as well as the above properties may be obtained by coating a polyvinylidene chloride resin prior to the stretching so that its solid content after the stretching becomes at least
Inventors
- 👤 Kiyoshi Kitagawa
- 👤 Atsushi Komatsuzaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 15:56
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/34; B29; B29C; B29C61/00; B29C61/003; B29C61/06; B29C61/0608; B29C61/0616; B32B27/06; B32B27/08; B32B27/30; B32B27/304; C; C08; C08J; C08J5/00; C08J5/18; C08J7/00; C08J7/04; C08J7/0427; C08J7/048; B29K; B29K2027/00; B29K2027/06; B29K2077/00; B32B2307/00; B32B2307/50; B32B2307/514; B32B2307/518; B32B2307/70; B32B2307/702; B32B2307/724; B32B2307/732; B32B2307/734; B32B2307/736; C08J2377/00; C08J2427/00; Y; Y10; Y10T; Y10T428/00; Y10T428/27; Y10T428/273; Y10T428/28; Y10T428/2813; Y10T428/2817; Y10T428/2826; Y10T428/31504; Y10T428/31725; Y10T428/31739; Y10T428/31743; Y10T428/31746; Y10T428/31855; Y10T428/31938
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
31 words
1) A shrinkable polyamide film having a hydrothermal shrinking ratio of at least 30% in both MD and TD, and a hydrothermal shrinkage stress of from 300 to 700 g/mm 2.
Claim 2
Dependent Claim
31 words
1) A shrinkable polyamide film having a hydrothermal shrinking ratio of at least 30% in both MD and TD, and a hydrothermal shrinkage stress of from 300 to 700 g/mm 2.
Claim 3
Dependent Claim
64 words
2) A shrinkable polyamide film coated, on at least one side thereof, with a polyvinylidene chloride resin and having a hydrothermal shrinking ratio of at least 30% in both MD and TD, a hydrothermal shrinkage stress of from 300 to 700 g/mm 2 and an oxygen gas permeability of not more than 20 cc/m 2 24 hrs. atm. as measured by the Mocon method.
Claim 4
Dependent Claim
64 words
2) A shrinkable polyamide film coated, on at least one side thereof, with a polyvinylidene chloride resin and having a hydrothermal shrinking ratio of at least 30% in both MD and TD, a hydrothermal shrinkage stress of from 300 to 700 g/mm 2 and an oxygen gas permeability of not more than 20 cc/m 2 24 hrs. atm. as measured by the Mocon method.
Claim 5
Dependent Claim
107 words
3) A process for producing a shrinkable polyamide film having a hydrothermal shrinking ratio of at least 30% in both MD and TD and a hydrothermal shrinkage stress of from 300 to 700 g/mm2, which process comprises biaxially stretching a substantially amorphous film composed of a copolymer of 6,6-nylon/6-nylon in a weight ratio within a range of from 5/95 to 25/75 at a temperature of not higher than 120°C and at a stretching ratio of at least 2.5 times in both MD and TD, and subjecting the stretched film to stress relaxation at a temperature of from the stretching temperature to 170°C, followed by winding it up.
Claim 6
Dependent Claim
107 words
3) A process for producing a shrinkable polyamide film having a hydrothermal shrinking ratio of at least 30% in both MD and TD and a hydrothermal shrinkage stress of from 300 to 700 g/mm2, which process comprises biaxially stretching a substantially amorphous film composed of a copolymer of 6,6-nylon/6-nylon in a weight ratio within a range of from 5/95 to 25/75 at a temperature of not higher than 120°C and at a stretching ratio of at least 2.5 times in both MD and TD, and subjecting the stretched film to stress relaxation at a temperature of from the stretching temperature to 170°C, followed by winding it up.
Claim 7
Dependent Claim
105 words
4) The process as claimed in Claim 3 for producing a shrinkable polyamide film coated, on at least one side thereof, with a polyvinylidene chloride resin and having a hydrothermal shrinking ratio of at least 30% in both MD and TD, a hydrothermal shrinkage stress of from 300 to 700 g/mm 2 and an oxygen gas permeability of not more than 20 cc/m 2 · 24 hrs. atm. as measured by the Mocon method, wherein prior to the stretching, a polyvinylidene chloride resin is coated on the substantially amorphous film so that its solid content after the stretching becomes at least 0.5 g/m 2 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.