US4223101A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing fibrous structure
Assignee: BASF Corp
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Filing: 1978-07-17
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Granted: 1980-09-16
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Expires: 1998-07-17
Abstract
Abstract A solution of elastomeric polyurethane in a volatile solvent is centrifugally sprayed onto a base in a strong electrostatic field to form long fibers that are swept across the base and deposited thereon in generally straight condition, overlapping and adhered to previously deposited fibers. Novel fibrous sheets of high strength are thus produced. The intersecting fibers may be ribbon-like.
Inventors
- 👤 Jerome Fine
- 👤 Sigismondo A. De Tora
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:39
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/0007; D01D5/0015; D01D5/003; D01D5/0038; B; B29; B29C; B29C41/00; B29C41/02; B29C41/08; D01D5/0061; D01D5/0069; D01D5/18; D01F; D01F6/00; D01F6/58; D01F6/70; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D04H1/56; D04H1/70; D04H1/72; D04H1/728; D04H1/76; B29C41/085; Y; Y10; Y10S; Y10S428/00; Y10S428/904; Y10T; Y10T428/00; Y10T428/23907; Y10T428/2395; Y10T428/24; Y10T428/24355; Y10T428/24438
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
227 words
A process for producing fibrous structures comprising: (a) supplying a liquid solution of a thermoplastic elastomeric polyurethane in a volatile solvent to a surface rotating about an axis to form thereon a film which is whirled from said surface by centrifugal force, (b) maintaining an electrostatic potential between said film and a collecting surface transverse to said axis to form said solution into electrically charged fibers, to attract said fibers to said collecting surface in a fiber pattern which, owing to said centrifugal force, is a whirling pattern annular to said axis, and to deposit, on said collecting surface, fibers oriented circumferentially of said annular pattern in paths having a radius of curvature above 4 cm. (c) evaporating said solvent during the travel of said solution from the rotating surface to said collecting surface so that the deposited fibers contain sufficient solvent to bond to fibers previously deposited upon said collecting surface, and thereby form a fibrous structure and (d) removing said deposited fibrous structure from said collecting surface, the distance between said collecting surface and said film being sufficient that there is no spark or visible corona discharge passing through the atmosphere from the rotating surface carrying said film to said collecting surface, said supplied solution of step (a) having a viscosity of above 500 centipoises and said polyurethane having an intrinsic viscosity of above 0.7.
Claim 2
Dependent Claim
227 words
A process for producing fibrous structures comprising: (a) supplying a liquid solution of a thermoplastic elastomeric polyurethane in a volatile solvent to a surface rotating about an axis to form thereon a film which is whirled from said surface by centrifugal force, (b) maintaining an electrostatic potential between said film and a collecting surface transverse to said axis to form said solution into electrically charged fibers, to attract said fibers to said collecting surface in a fiber pattern which, owing to said centrifugal force, is a whirling pattern annular to said axis, and to deposit, on said collecting surface, fibers oriented circumferentially of said annular pattern in paths having a radius of curvature above 4 cm. (c) evaporating said solvent during the travel of said solution from the rotating surface to said collecting surface so that the deposited fibers contain sufficient solvent to bond to fibers previously deposited upon said collecting surface, and thereby form a fibrous structure and (d) removing said deposited fibrous structure from said collecting surface, the distance between said collecting surface and said film being sufficient that there is no spark or visible corona discharge passing through the atmosphere from the rotating surface carrying said film to said collecting surface, said supplied solution of step (a) having a viscosity of above 500 centipoises and said polyurethane having an intrinsic viscosity of above 0.7.
Claim 3
Dependent Claim
28 words
Process as in claim 1 in which the rotating surface is maintained at a positive potential of at least about 50 KV and said collecting surface is grounded.
Claim 4
Dependent Claim
36 words
Process as in claim 1 in which the solution contains about 5 to 20% of the polyurethane dissolved in tetrahydrofuran and the polyurethane is a polyester polyurethane having an intrinsic viscosity of at least about 0.9.
Claim 5
Dependent Claim
23 words
Process as in claim 1 and including the step of moving said collecting surface whereby to transverse said annular pattern over said surface.
Claim 6
Dependent Claim
30 words
Process as in claim 4 in which said collecting surface is a moving endless web having a substantially flat collecting face perpendicular to said axis and said axis is stationary.
Claim 7
Dependent Claim
41 words
Process as in claim 4 in which said collecting surface if a moving endless web having a substantially flat collecting face perpendicular to said axis and said axis is traversed in a direction transverse to the movement of said collecting face.
Claim 8
Dependent Claim
16 words
Process as in claim 1 in which the process is effected in a substantially quiescent atmosphere.
Claim 9
Dependent Claim
41 words
Process as in claim 1 in which said rotating surface has an external circular rim over which said film of solution flows, the rate of rotation being such that said rim moves at a speed above about 3000 inches per minute.
Claim 10
Dependent Claim
70 words
Process as in claim 1 in which said process is continued so as to deposit fibers one onto the other until the deposited fibrous structure weighs at least about 30 grams per square yard, and a volatile solvent for said elastomer is then applied to one face of the fibrous structure in amount sufficient to smooth it and increase its abrasion resistance but insufficient to destroy its main fibrous structure.
Claim 11
Dependent Claim
45 words
Process as in claim 1 in which said fibers are deposited on a three dimensional body whose surface is said collecting surface, and said body and said axis are moved relative to one another whereby to deposit a continuous hollow fibrous structure around said body.
Claim 12
Dependent Claim
18 words
Process as in claim 10 and including the step of stripping said hollow fibrous structure from said body.
Claim 13
Dependent Claim
20 words
Process as in claim 1 and including the step of heating said deposited fibrous structure to remove residual volatile solvent.
Claim 14
Dependent Claim
33 words
Process as in claim 1 in which said axis is vertical and said collecting surface is horizontal and situated above said rotating surface, and the process is effected in a substantially quiescent atmosphere.
Claim 15
Dependent Claim
24 words
Process as in claim 1 in which said solution contains a polyurethane having an intrinsic viscosity of at least about 0.9 dissolved in tetrahydrofuran.
Claim 16
Dependent Claim
84 words
A process as in claim 1, said process yielding a fibrous structure consisting essentially of substantially straight elastomeric fibers extending substantially parallel to the surface of said structure, said fibers criss-crossing in all directions and being autogenously bonded to each other at crossing points without substantial change in width at their bond points, said structure having a density within the range of 0.1 to 0.6 g/cc., the process being continued until the weight of the deposited structure is above 15 grams per square yard.
Claim 17
Dependent Claim
26 words
Process as in claim 15 and including the step of heating said structure to remove residual volatile solvent after removing said structure from said collecting surface.
Claim 18
Dependent Claim
34 words
Process as in claim 5 in which there are a plurality of said rotating surfaces each having a stationary vertical axis of rotation, said rotating surfaces being spaced across the width of said web.
Claim 19
Dependent Claim
201 words
Process as in claim 14 in which the radius of curvature in step (b) is greater than 7 cm, the construction and arrangement is such that in its flow at said rim said film is in contact with a solid confining surface only at one face of said film, the opposite face of said film at said rim being exposed to the atmosphere, and in which said collecting surface is a moving endless web having a substantially flat horizontal collecting face, there are a plurality of said rotating surfaces below said collecting face, each of said plurality having a stationary vertical axis of rotation, said rotating surfaces being spaced across the width of said web, said process being effected in a substantially quiet atmosphere and yielding a fibrous structure consisting essentially of substantially straight elastomeric fibers extending substantially parallel to the surface of said structure, said fibers criss-crossing in all directions and being autogenously bonded to each other at crossing points without substantial change in width at their bond points, said structure having a density within the range of 0.1 to 0.6 g/cc., the deposition being continued until the weight of the deposited structure is above 15 grams per square yard.
Claim 20
Dependent Claim
10 words
The fibrous structure produced by the process of claim 1.
Claim 21
Dependent Claim
10 words
A fibrous structure produced by the process of claim 18.
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) | 1983-09-16 | 1984-03-17 | 1984-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-09-16 | 1988-03-17 | 1988-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-09-16 | 1992-03-17 | 1992-09-16 | $7700.00 | Window Closed / Lapsed |