Patent US4460642A successfully refreshed from Google Patents.
US4460642A
Expired / Lapsed
US
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Water-swellable composite sheet of microfibers of PTFE and hydrophilic absorptive particles
Assignee: 3M Co
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Filing: 1982-11-23
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Granted: 1984-07-17
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Expires: 2002-11-23
Abstract
Abstract A composite sheet material is highly absorbent toward aqueous fluids including blood and exudate and comprises a polytetrafluoroethylene fibril matrix and hydrophilic absorptive particles enmeshed in the matrix. The composite sheet material is useful as a wound dressing, as a drying material for non-aqueous solvents, and as a chromatographic material.
Inventors
- 👤 Louis A. Errede
- 👤 James D. Stoesz
- 👤 Jenny Upton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:47
CPC Classifications
A; A61; A61L; A61L15/00; A61L15/16; A61L15/42; A61L15/60; A61F; A61F13/00; A61F13/01; A61F13/01008; A61L15/22; A61L15/24; A61F13/15; A61F13/84; A61F13/8405; A61F2013/00089; A61F2013/00246; A61F2013/00361; A61F2013/00365; A61F2013/00463; A61F2013/00472; A61F2013/00902; A61F2013/0091; A61F2013/00927; A61F2013/00931; A61F13/53; A61F2013/530481; A61F2013/530489; A61F2013/530496; Y; Y10; Y10S; Y10S428/00; Y10S428/903; Y10T; Y10T428/00; Y10T428/31504; Y10T428/3154; Y10T428/31544; Y10T442/00; Y10T442/60; Y10T442/608; Y10T442/614; Y10T442/626; Y10T442/637; Y10T442/642; Y10T442/699
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
65 words
A composite sheet material comprising: (a) a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix, and (b) 1.0 to 10 parts of hydrophilic absorptive particles per part of PTFE by weight enmeshed in said matrix, the absorptive particles having absorptive capacity greater than 1.0 gram of water per gram of dry particles, wherein substantially all of said hydrophilic absorptive particles are unavailable for sloughing.
Claim 2
Dependent Claim
65 words
A composite sheet material comprising: (a) a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix, and (b) 1.0 to 10 parts of hydrophilic absorptive particles per part of PTFE by weight enmeshed in said matrix, the absorptive particles having absorptive capacity greater than 1.0 gram of water per gram of dry particles, wherein substantially all of said hydrophilic absorptive particles are unavailable for sloughing.
Claim 3
Dependent Claim
55 words
The composite sheet material according to claim 1 wherein said hydrophilic absorbent particles are alginic acid, polyacrylatecellulose graft copolymer, collagen, phosphate crosslinked starch substituted with hydroxypropyl or carboxymethyl groups, chitin, chitosan, crosslinked dextran, crosslinked carboxymethyldextran, crosslinked diethylaminoethyl dextran, starch, hydroxyethyl starch, hydrolyzed polyacrylonitrile, starch-methacrylonitrile polymer, polyacrylamide, hydrolyzed polyacrylamide, cellulose, carboxymethylcellulose or derivatives or mixtures thereof.
Claim 4
Dependent Claim
20 words
The composite sheet material according to claim 1 wherein said hydrophilic absorptive particles are particles of a crosslinked dextran derivative.
Claim 5
Dependent Claim
19 words
The composite sheet material according to claim 1 wherein said hydrophilic absorptive particles are admixed with inert diluent particles.
Claim 6
Dependent Claim
25 words
The composite sheet material according to claim 4 wherein said inert diluent particles are selected from polyethylene, polypropylene, polystyrene, kaolin, talc, silica, bentonite, and vermiculite.
Claim 7
Dependent Claim
24 words
The composite sheet material according to claim 4 wherein said particles comprise 40 to 90 percent of the weight of said composite sheet material.
Claim 8
Dependent Claim
25 words
The composite sheet material according to claim 4 wherein said particles comprise about 80 to 90 percent of the weight of said composite sheet material.
Claim 9
Dependent Claim
22 words
The composite sheet material according to claim 1 wherein said hydrophilic absorbent particles range in size from about 0.1 to 300 micrometers.
Claim 10
Dependent Claim
22 words
The composite sheet material according to claim 1 wherein said hydrophilic absorbent particles range in size from about 1.0 to 80 micrometers.
Claim 11
Dependent Claim
26 words
The composite sheet material according to claim 1 wherein said fibril matrix comprises fibrils having a thickness in the range of about 0.025 to 0.5 micrometers.
Claim 12
Dependent Claim
29 words
The composite sheet material according to claim 1 wherein said composite sheet material has a tensile strength in the range of 75 to 1000 psi (0.5 to 6.67 megapascals).
Claim 13
Dependent Claim
22 words
The composite sheet material according to claim 1 wherein said material has a thickness in the range of 0.1 to 10 mm.
Claim 14
Dependent Claim
22 words
The composite sheet material according to claim 1 further comprising medicaments selected from antibacterial agents, antifungal agents, hemostatic agents, and wound-healing agents.
Claim 15
Dependent Claim
28 words
The composite sheet material according to claim 1 wherein said hydrophilic absorptive particles are present in a range of 2.0 to 10 parts per part PTFE by weight.
Claim 16
Independent Claim
90 words
A method of removing water from non-aqueous solvents comprising the steps: (1) passing said solvent over or through a composite sheet material comprising: (a) a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix; and (b) 1.0 to 10 parts of hydrophilic absorptive particles per part of PTFE by weight enmeshed in said matrix, the absorptive particles having absorptive capacity greater than 1.0 grams of water per gram of dry particles, wherein substantially all of said hydrophilic absorptive particles are unavailable for sloughing, and (2) recovering the resulting aqueous-free solvent.
Claim 17
Independent Claim
90 words
A method of removing water from non-aqueous solvents comprising the steps: (1) passing said solvent over or through a composite sheet material comprising: (a) a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix; and (b) 1.0 to 10 parts of hydrophilic absorptive particles per part of PTFE by weight enmeshed in said matrix, the absorptive particles having absorptive capacity greater than 1.0 grams of water per gram of dry particles, wherein substantially all of said hydrophilic absorptive particles are unavailable for sloughing, and (2) recovering the resulting aqueous-free solvent.
Claim 18
Dependent Claim
65 words
A chromatographic sheet material comprising: (a) a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix, and (b) 1.0 to 10 parts of hydrophilic absorptive particles per part of PTFE by weight enmeshed in said matrix, the absorptive particles having absorptive capacity greater than 1.0 gram of water per gram of dry particles, wherein substantially all of said hydrophilic absorptive particles are unavailable for sloughing.
Claim 19
Dependent Claim
65 words
A chromatographic sheet material comprising: (a) a network of interlaced microfibrous polytetrafluoroethylene forming a fibril matrix, and (b) 1.0 to 10 parts of hydrophilic absorptive particles per part of PTFE by weight enmeshed in said matrix, the absorptive particles having absorptive capacity greater than 1.0 gram of water per gram of dry particles, wherein substantially all of said hydrophilic absorptive particles are unavailable for sloughing.
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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) | 1987-07-17 | 1988-01-16 | 1988-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-17 | 1992-01-16 | 1992-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-17 | 1996-01-16 | 1996-07-17 | $7700.00 | Window Closed / Lapsed |