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US 4,460,642 AGranted
Water-swellable composite sheet of microfibers of PTFE and hydrophilic absorptive particles
AssigneeMinnesota Mining and Manufacturing Company
InventorsLouis A. Errede, James D. Stoesz, Jenny Upton
Life of this patent
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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.
Claims16
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.
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.
3 more elements
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.
Dependencies are inferred from the claim text.