Patent US4180611A successfully refreshed from Google Patents.
US4180611A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Smooth-surfaced nonwoven fabric
Assignee: Carl Freudenberg KG
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Filing: 1977-12-01
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Granted: 1979-12-25
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Expires: 1997-12-01
Abstract
Abstract A nonwoven fabric having a smooth surface, especially for use as support material for semipermeable membranes, comprising a support mat into which at least one surface thereof, an open-structured, continuous covering layer of fine, thermoplastic particles is calendered.
Inventors
- 👤 Wolfram Schultheiss
- 👤 Klaus Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:28
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/10; B01D69/107; B01D69/1071; Y; Y10; Y10S; Y10S428/00; Y10S428/903; Y10T; Y10T428/00; Y10T428/26; Y10T428/27; Y10T428/29; Y10T428/2982; Y10T442/00; Y10T442/60; Y10T442/608; Y10T442/609; Y10T442/611; Y10T442/659; Y10T442/673
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
92 words
A nonwoven fabric having a smooth surface, especially for use as a support material for a semipermeable membrane, comprising a support mat having at least one surface into which there has been calendered an open structured porous covering layer of fine flat fibers having a thickness of less than about 30×10 -6 m, the covering layer having a specific weight of about 1 to 200 g/m 2 and having been formed by electrostatically spinning the fibers directly onto the support mat, the support mat extending over the entire width of the fabric.
Claim 2
Dependent Claim
92 words
A nonwoven fabric having a smooth surface, especially for use as a support material for a semipermeable membrane, comprising a support mat having at least one surface into which there has been calendered an open structured porous covering layer of fine flat fibers having a thickness of less than about 30×10 -6 m, the covering layer having a specific weight of about 1 to 200 g/m 2 and having been formed by electrostatically spinning the fibers directly onto the support mat, the support mat extending over the entire width of the fabric.
Claim 3
Dependent Claim
19 words
A fabric according to claim 1, wherein the fiber thickness is from about 1×10 -6 to 20×10 -6 m.
Claim 4
Dependent Claim
22 words
A fabric according to claim 1, wherein the covering layer has a specific weight of about 10 to 40 g/m 2 .
Claim 5
Dependent Claim
25 words
In a system for filtration using a semipermeable membrane, the improvement which comprises using said membrane supported on a nonwoven fabric according to claim 1.
References Cited (Backward Citations)
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US3837995A
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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) | 1982-12-24 | 1983-06-25 | 1983-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-24 | 1987-06-25 | 1987-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-24 | 1991-06-25 | 1991-12-25 | $7700.00 | Window Closed / Lapsed |