Patent US4164529A successfully refreshed from Google Patents.
US4164529A
Expired / Lapsed
US
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Process for preparing tubular film of hydrolyzed ethylene-vinyl acetate copolymer
Assignee: Mitsubishi Chemical Corp
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Filing: 1977-10-04
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Granted: 1979-08-14
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Expires: 1997-10-04
Abstract
Abstract In a typical tubular extrusion of hydrolyzed ethylene-vinyl acetate copolymer having an ethylene content of 15 to 50% by mole and a degree of hydrolysis in the vinyl acetate units of not less than 90% by mole, an improved process for preparing the tubular film without wrinkle by controlling the surface temperature of the tubular film at the nip rolls within the range of 50° to 100° C.
Inventors
- 👤 Yukio Fujita
- 👤 Teruo Iwanami
- 👤 Yoshimi Akamatsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:22
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/03; B29C48/001; B29C48/0018; B29C48/0019; B29C48/09; B29C48/10
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
111 words
In a process for preparing a continuous tubular film of hydrolyzed ethylene-vinyl acetate copolymers by melt-extruding the hydrolyzed copolymer through a circular die in the form of tube, expanding the tube to a bubble by the pressure of internal air admitted through a mandrel, collapsing the bubble and winding up the film through nip rolls, the improvement which comprises employing hydrolyzed ethylene-vinyl acetate copolymers having an ethylene content of 15 to 50% by mole and a degree of hydrolysis in the vinyl acetate units of not less than 90% by mole and maintaining the surface temperature of the film at the nip rolls within the range of 50° to 100° C.
Claim 2
Dependent Claim
111 words
In a process for preparing a continuous tubular film of hydrolyzed ethylene-vinyl acetate copolymers by melt-extruding the hydrolyzed copolymer through a circular die in the form of tube, expanding the tube to a bubble by the pressure of internal air admitted through a mandrel, collapsing the bubble and winding up the film through nip rolls, the improvement which comprises employing hydrolyzed ethylene-vinyl acetate copolymers having an ethylene content of 15 to 50% by mole and a degree of hydrolysis in the vinyl acetate units of not less than 90% by mole and maintaining the surface temperature of the film at the nip rolls within the range of 50° to 100° C.
Claim 3
Dependent Claim
45 words
The process of claim 1, wherein a polyolefin is melted in an extruder and is extruded together with the melted hydrolyzed ethylene-vinyl acetate copolymer to give a laminated film consisting of an outer layer of the polyolefin and an inner layer of the hydrolyzed copolymer.
Claim 4
Dependent Claim
21 words
The process of claim 1, wherein the temperature of the film passing through nip rolls is from 55° to 90° C.
Claim 5
Dependent Claim
18 words
The process of claim 1, wherein the tubular film is subjected to biaxial orientation before reaching nip rolls.
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) | 1982-08-13 | 1983-02-12 | 1983-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-13 | 1987-02-12 | 1987-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-13 | 1991-02-12 | 1991-08-14 | $7700.00 | Window Closed / Lapsed |