Patent EP0240632A2 successfully refreshed from Google Patents.
EP0240632A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Heat-shrinkable biaxially drawn polyamide film and process for preparaton thereof
Assignee: Mitsubishi Chemical Corp
•
Filing: 1986-04-11
•
Granted: —
•
Expires: 2006-04-11
Abstract
Abstract Disclosed is a heat-shrinkable biaxially drawn polyamide film which is formed from a homopolymer or copolymer of ε-caprolactam or a polyblend thereof, by a sequential biaxial drawing method and which has a density of 1.129 to 1.136 g/cm³ and an in-plane orientation index of 0.0535 to 0.0580. This film is prepared by the steps of drawing in the machine direction a substantially amorphous unoriented polyamide film at 45 to 65°C, a deformation rate of at least 10,000%/min and a draw ratio of 2.7 to 3.5 by a roll type longitudinal drawing method, gripping the ends of the film by tenter clips, drawing the film in the transverse direction at a film temperature not higher than 100°C, an average deformation rate of 2,000 to 10,000%/min and a draw ratio of 3 to 5, and heat-treating the film at 125 to 170°C while gripping the ends of the film by the tenter clips.
Inventors
- 👤 Tsuguo Okumura
- 👤 Kazuharu Abe
- 👤 Kenji Mori
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 11:29
CPC Classifications
B; B29; B29C; B29C61/00; B29C61/003; B29C55/00; B29C55/02; B29C55/10; B29C55/12; B29C55/14; B29C55/143; B29C71/00; B29K; B29K2077/00; B29K2995/00; B29K2995/0037; B29K2995/0049; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31725
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
76 words
A heat-shrinkable biaxially drawn polyamide film, which is formed from a homopolymer derived from ε-caprolactam or a copolymer derived from 90 to 98 mole% of ε-caprolacatam and 2 to 10 mole% of at least one copolymerizable monomer, or a polyblend containing 80 to 95% by weight of said homopolymer or copolymer, by a sequential biaxial drawing method, characterized by having a density of 1.129 to 1.136 g/cm³ and an in-plane orientation index of 0.0535 to 0.0580.
Claim 2
Dependent Claim
76 words
A heat-shrinkable biaxially drawn polyamide film, which is formed from a homopolymer derived from ε-caprolactam or a copolymer derived from 90 to 98 mole% of ε-caprolacatam and 2 to 10 mole% of at least one copolymerizable monomer, or a polyblend containing 80 to 95% by weight of said homopolymer or copolymer, by a sequential biaxial drawing method, characterized by having a density of 1.129 to 1.136 g/cm³ and an in-plane orientation index of 0.0535 to 0.0580.
Claim 3
Dependent Claim
20 words
The film according to claim 1, wherein the thickness of the biaxially drawn polyamide film is 10 to 50 µm.
Claim 4
Dependent Claim
117 words
A process for the preparation of a heat-shrinkable biaxially drawn polyamide film, which comprises drawing in the machine direction a substantially amorphous unoriented polyamide film at a temperature of 45 to 65°C, a deformation rate of at least 10,000%/min and a draw ratio of 2.7 to 3.5 by a roll type longitudinal drawing method, gripping the ends of the film by tenter clips, drawing the film in the transverse direction at a film temperature not higher than 100°C, an average deformation rate of 2,000 to 10,000%/min and a draw ratio of 3 to 5, and heat-treating the drawn film at a temperature of 125 to 170°C while gripping the ends of the film by the tenter clips.
Claim 5
Dependent Claim
117 words
A process for the preparation of a heat-shrinkable biaxially drawn polyamide film, which comprises drawing in the machine direction a substantially amorphous unoriented polyamide film at a temperature of 45 to 65°C, a deformation rate of at least 10,000%/min and a draw ratio of 2.7 to 3.5 by a roll type longitudinal drawing method, gripping the ends of the film by tenter clips, drawing the film in the transverse direction at a film temperature not higher than 100°C, an average deformation rate of 2,000 to 10,000%/min and a draw ratio of 3 to 5, and heat-treating the drawn film at a temperature of 125 to 170°C while gripping the ends of the film by the tenter clips.
Claim 6
Dependent Claim
18 words
The process according to claim 3, wherein the deformation rate in the longitudinal drawing is 10,000 to 50,000%/min.
Claim 7
Dependent Claim
101 words
The process according to claim 3 or 4, wherein the film drawn in the machine direction is immediately maintained at a temperature of 45 to 60°C and transferred to the position for initiation of the transverse drawing within a time represented by the following formula (II): t = ϑ (3.9-0.053T₁) (II) wherein t represents the time (seconds) between the point of completion of the drawing in the machine direction and the point of initiation of the drawing in the transverse direction, and T₁ represents the film temperature during this time, which is selected within the range of from 45 to 60°C.
Claim 8
Dependent Claim
71 words
The process according to any of claims 3 through 5, wherein the thickness profile of the film at the position for initiation of the transverse drawing be such that the thickness is gradually reduced from the end portion in the transverse direction toward the central portion in the transverse direction, and the thickness of the film is 75 to 90% of the thickness in the end portion in the transverse direction.
Claim 9
Dependent Claim
64 words
The process according to any of claims 3 through 6, wherein until the draw ratio in the transverse direction exceeds 1.4, the film is expanded while controlling the expanding angle to the central line perpendicular to the transverse direction of the film within 6° and maintaining the temperature T₂ of the tenter clips at a level lower than the temperature T₁ of the film.
Claim 10
Dependent Claim
44 words
The process according to any of claims 3 through 7, wherein the film temperature is elevated stepwise from the position for initiation of the transverse drawing so that at the position of completion of the transverse drawing the film temperature is 70 to 100°C.
Claim 11
Dependent Claim
22 words
The process according to any of claims 3 through 8, wherein the draw ratio in the transverse drawing is 3.5 to 4.5.
Claim 12
Dependent Claim
28 words
The process according to any of claims 3 through 9, wherein the drawn film is heat-treated at a temperature of 130 to 160°C for one to ten seconds.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.