Flexible air permeable non-woven fabric filters
AssigneeHughes Aircraft Company
InventorCharles H. Sherwood
Life of this patent
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Abstract
A flexible, air permeable composite highly effective as a highly absorbent fiber filter, suitable for high throughput, low pressure drop applications. The composites and filters use a non-woven fabric substrate, in conjunction with organic polymer fibers, such as polypropylene fibers, formed in-situ from a solvent solution of the polymer, with solid particles such as carbon particles interstitially positioned within the mass, and forming a unique microstructure by the interaction of the flexible non-woven fibers and the polymer fibers. A method of entrapping small sorptive particles within such filters is also provided.
Claims23
A tailorable air permeable flexible composite for use in the fabrication of filters, comprising a fiber mass formed of a randomly oriented mixture of flexible non-woven substrate fibers, and in-situ formed organic polymer fibers intertwined with said non-woven fibers and containing solid sorptive microscopic particles essentially captured against said non-woven fibers, to form a flexible, air permeable, highly absorbent fiber filter.
A tailorable air permeable, flexible composite for use in the fabrication of filters, comprising a fiber mass formed of a randomly oriented mixture of flexible non-woven substrate aromatic polyamide fibers and in-situ formed crystalline polypropylene fibers formed around said non-woven fibers, with a relatively small amount of said in-situ fibers extending between said non-woven fibers, and containing carbon particles of a size within the range of about 2 to 5 micrometers, said carbon particles comprising a major proportion of the weight of said composite, and said carbon particles essentially captured against said non-woven fibers and between said in-situ fibers and said non-woven fibers, to form a flexible, air permeable, highly absorbent fiber filter.
A method of entrapping small sorptive particles within a fiber mass which comprises precipitating organic polymer fibers from an organic solvent solution of (1) a fiber-forming organic polymer and containing (2) suspended small sorptive solid particles and (3) flexible non-woven substrate fibers, and forming a fiber mass comprised of a mixture of flexible, non-woven substrate fibers and organic polymer fibers intertwined with each other and containing small solid sorptive particles interstitially positioned within said mass, to form a flexible, air permeable, highly absorbent fiber filter.
A method of entrapping small sorptive particles and producing a tailorable air permeable flexible composite which comprises:
- (a) introducing into a hot organic solvent solution of a fiber-forming organic polymer containing suspended small sorptive solid particles, flexible non-woven substrate fibers;
- (b) subjecting said solution to agitation and cooling to a temperature which causes precipitation of fibers of said organic polymer from said solution, said organic fibers forming in-situ around the non-woven fibers of said substrate, and said solid particles captured against said non-woven fibers and between said in-situ formed fibers and said non-woven fibers;
- (c) removing the resulting fibrous mass from said solution;
- (d) washing said fibrous mass with fresh solvent;
- and
- (e) drying said fibrous mass.
Dependencies are inferred from the claim text.