US4130616A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tubular extrudate
Assignee: Imperial Chemical Industries Ltd
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Filing: 1977-06-07
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Granted: 1978-12-19
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Expires: 1997-06-07
Abstract
Abstract Cooling a tubular extrudate for conversion to tubular film by passing the extrudate through a bath of cooling liquid so that the external surface of the extrudate contacts in sequence countercurrent streams of cooling liquid in a quiescent zone, a restricted throttle zone and a spiral flow zone.
Inventors
- 👤 Michael L. Clifford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:53
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/919; B29C48/911; B29C48/9115; B29C48/912; B29C48/001; B29C48/0018; B29C48/03; B29C48/09; B29C48/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
145 words
A method of producing a polymeric tubular film comprising extruding a tube of a film-forming polymeric material, passing the extruded tube over and around an internal cooling mandrel, axially withdrawing the tube while supported on the mandrel through a bath of cooling liquid such that the external surface of the tube contacts in sequence (a) a quiescent zone, of surface area A, of cooling liquid exhibiting laminar flow, (b) a zone, of restricted cross-sectional area B, of cooling liquid exhibiting transitional flow, and (c) a zone, of cross-sectional area C, of cooling liquid exhibiting substantially spiral turbulent flow around the surface of the tube, the flow of cooling liquid in each of said zones being substantially countercurrent to the direction of movement of the tube, and the surface areas of said zones being such that A>B<C, and thereafter converting the cooled tube to tubular film.
Claim 2
Independent Claim
145 words
A method of producing a polymeric tubular film comprising extruding a tube of a film-forming polymeric material, passing the extruded tube over and around an internal cooling mandrel, axially withdrawing the tube while supported on the mandrel through a bath of cooling liquid such that the external surface of the tube contacts in sequence (a) a quiescent zone, of surface area A, of cooling liquid exhibiting laminar flow, (b) a zone, of restricted cross-sectional area B, of cooling liquid exhibiting transitional flow, and (c) a zone, of cross-sectional area C, of cooling liquid exhibiting substantially spiral turbulent flow around the surface of the tube, the flow of cooling liquid in each of said zones being substantially countercurrent to the direction of movement of the tube, and the surface areas of said zones being such that A>B<C, and thereafter converting the cooled tube to tubular film.
Claim 3
Dependent Claim
20 words
A method according to claim 1 wherein the Reynolds Number of the cooling liquid flowing in zone (c) exceeds 3000.
Claim 4
Dependent Claim
35 words
A method according to claim 1 wherein a major portion of the cooling liquid flowing in zone (c) is discharged therefrom downstream, in the direction of movement of the extruded tube, of restricted zone (b).
Claim 5
Dependent Claim
17 words
A method according to claim 1 wherein additional cooling liquid is introduced directly into quiescent zone (a).
Claim 6
Dependent Claim
25 words
A method according to claim 1 wherein the axial dimensions of the quiescent (a), restricted (b), and spiral flow (c) zones are such that c>a>b.
Claim 7
Dependent Claim
19 words
A method according to claim 1 wherein a sheath of heat-transfer liquid is maintained between the mandrel and tube.
Claim 8
Dependent Claim
19 words
A method according to claim 1 wherein the polymeric material is a stereoregular predominantly crystalline homo- or co-polymer propylene.
Claim 9
Dependent Claim
14 words
A method according to claim 1 wherein the tube is a coextruded multiple-layer tube.
Claim 10
Dependent Claim
49 words
A method according to claim 8 wherein the tube comprises a polypropylene substrate and a surface layer of a copolymer containing from 80 to 95 wt % of propylene and from 5 to 20 wt % of an alpha-olefin having from 4 to 10 carbon atoms in its molecule.
References Cited (Backward Citations)
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US3427375A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-12-18 | 1982-06-19 | 1982-12-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-12-18 | 1986-06-19 | 1986-12-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-12-18 | 1990-06-19 | 1990-12-19 | $7700.00 | Window Closed / Lapsed |