Patent US3873254A successfully refreshed from Google Patents.
US3873254A
Expired / Lapsed
US
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Apparatus for making water vapour permeable polymer sheet materials
Assignee: Porvair PLC
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Filing: 1973-02-05
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Granted: 1975-03-25
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Expires: 1993-02-05
Abstract
Abstract Coagulation apparatus for producing thick microporous polyurethane sheet material by passing a layer of polymer solvent composition beneath a close spaced plate with liquid non-solvent fed to the gap between the plate and the surface to produce controlled initiation of the coagulation.
Inventors
- 👤 Eric Albert Warwicker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:53
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/26; B; B29; B29C; B29C44/00; B29C44/20; B29C48/00; B29C48/03; B29C48/07; B29C48/08; B29C48/25; B29C48/88; B29C48/911; B29C48/9135; B29C48/9145; B29C48/919
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
175 words
Apparatus for making a water vapor permeable polymer sheet material which comprises means for forming a layer of coagulable polymer composition at least 0.5mms thick, said layer having a free surface, and for passing said layer through a body of liquid, with said free surface in contact with said liquid, to coagulate said layer, characterised in that up-stream of said body of liquid there are means having a solid boundary, spaced from said free surface so that a slot is left between said boundary and said free surface and in that means are provided for supplying coagulating liquid down-stream of said slot so as to maintain a body of said liquid on said free surface and to keep the slot filled with said liquid and in that the thickness of the slot is such that when said liquid is supplied downstream its surface tension establishes a meniscus between said boundary and said free surface, the construction and arrangement being such that said free surface first comes into contact with said supplied liquid at said meniscus.
Claim 2
Dependent Claim
175 words
Apparatus for making a water vapor permeable polymer sheet material which comprises means for forming a layer of coagulable polymer composition at least 0.5mms thick, said layer having a free surface, and for passing said layer through a body of liquid, with said free surface in contact with said liquid, to coagulate said layer, characterised in that up-stream of said body of liquid there are means having a solid boundary, spaced from said free surface so that a slot is left between said boundary and said free surface and in that means are provided for supplying coagulating liquid down-stream of said slot so as to maintain a body of said liquid on said free surface and to keep the slot filled with said liquid and in that the thickness of the slot is such that when said liquid is supplied downstream its surface tension establishes a meniscus between said boundary and said free surface, the construction and arrangement being such that said free surface first comes into contact with said supplied liquid at said meniscus.
Claim 3
Dependent Claim
91 words
Apparatus as claimed in claim 1 in which said forming and passing means comprise a support, means for depositing said layer on said support and means for driving the support to carry said layer past said solid boundary, and in which the means having a solid boundary comprise a wall in substantially parallel relationship to said support and close to said free surface, said liquid supplying means being situated to supply said liquid downstream of said wall to form a thin film of liquid between said wall and said free surface.
Claim 4
Dependent Claim
17 words
Apparatus as in claim 2 in which said wall and meniscus are situated above said free surface.
Claim 5
Dependent Claim
24 words
Apparatus as in claim 2, said support being porous and there being means for supplying coagulating liquid to penetrate the pores of said support.
Claim 6
Dependent Claim
13 words
Apparatus as in claim 4 in which said support is an endless belt.
Claim 7
Dependent Claim
25 words
Apparatus as in claim 5 in which there are means upstream of said depositing means for controlling the amount of coagulating liquid in said belt.
Claim 8
Dependent Claim
44 words
Apparatus as in claim 3 in which said support is a porous endless belt, said driving means comprises means for driving said belt at a continuous speed in one direction, and said solid boundary and said wall are provided by an adjustably arranged plate.
Claim 9
Dependent Claim
33 words
Apparatus as claimed in claim 1 in which means are provided to maintain the free surface of the said sheet at least wetted with non solvent until the polymer is substantially completely coagulated.
Claim 10
Dependent Claim
44 words
Apparatus as claimed in claim 8 in which the said means comprise at least one covering sheet positioned above the polymer sheet downstream of the plate so as to establish a thin film of non solvent evenly over the surface of the polymer sheet.
Claim 11
Dependent Claim
142 words
Apparatus as claimed in claim 1 comprising means containing a body of liquid non solvent, means for introducing the layer on the support into the body of liquid non solvent at a substantial angle to the horizontal, plate means arranged to extend above the surface of the body of liquid non solvent so as to produce a slot between the free surface of the polymer layer on the support and the plate, the slot being of such dimensions that in conjunction with the height of the plate above the still surface of the body of liquid non solvent any ripples which are produced in the body of liquid as by the passage of the support into it are dampended out at the meniscus produced adjacent to the top of the plate between the free surface of the polymer sheet and the plate.
Claim 12
Dependent Claim
41 words
Apparatus as claimed in claim 1 which means are provided to maintain both the free surface of the said sheet and the free surface of the said support at least wetted with non solvent until the polymer is substantially completely coagulated.
Claim 13
Dependent Claim
26 words
Apparatus as in claim 1 in which the means having a solid boundary comprises a plate having its surface in contact with said body of liquid.
References Cited (Backward Citations)
US2510967A
Cited
US3609805A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |