Controlling the porosity and permeation of a web
AssigneeNextec Applications, Inc.
InventorJames M. Caldwell
Life of this patent
Estimating the term…
Abstract
Products and methods for controlling the porosity and permeation of a web are provided using a curable thixotropic shear thinnable polymer composition that preferably encapsulates a plurality of fibers of the web and/or forms an internal layer within the web. Webs suitable for several different uses are featured, for example medical garments resistant to permeation by a virus or bacteria. The effective pore size of the web is controlled by regulating various factors such as the thickness of the polymer composition encapsulating the fibers and the thickness and placement of the internal polymer layer. Other factors include the polymer density, structure, and crosslinking orientation, as well as the diffusion, permeation and sorption of the polymer.
Claims62
A method of controlling the effective pore size of a web,
- wherein said web has a three dimensional structure comprising structural elements with interstitial spaces therebetween and a top surface opposed from a bottom surface, comprising the steps of:
- tensioning the web;
- applying a curable, shear thinnable material to said web;
- subjecting said material to sufficient shear thinning energy to cause the material to flow into the web and selectively position within the web, wherein at least some of the structural elements of said web are substantially encapsulated by a thin film between about 0.01 and 50 microns of the material and wherein most of the interstitial spaces between structural elements of said web remain open;
- and
- at least partially curing the material with no substantial loss of material, to provide a treated web with an effective pore size between about 0.025 and 100 microns.
A method of controlling the effective pore size of a web having a matrix with open cells therein comprising the steps of:
- tensioning the web;
- applying a curable, shear thinnable material to said web;
- subjecting said material to sufficient shear thinning energy to cause the material to flow into the web and selectively position within the web, wherein at least some of the cells are at least partially individually lined with between about 0.01 and 50 microns of said material and most of said cells remain open;
- and
- at least partially curing the material with no substantial loss of material, to provide a treated web with an effective pore size between about 0.025 and 100 microns.
A method of controlling the effective pore size of a web,
- wherein said web has a three dimensional structure comprising structural elements with interstitial spaces therebetween and a top surface opposed from a bottom surface, comprising the steps of:
- selecting a curable, shear thinnable, substantially solvent free polymer composition having repeating polymeric units, physical entanglements and crosslinking reactive sites;
- tensioning the web;
- applying said polymer composition to said web;
- subjecting the polymer composition to sufficient shear thinning to reduce the physical entanglements and to form (a) a thin film between about 0.01 and 50 microns encapsulating at least some of the web members, leaving most of the interstitial spaces open and (b) a substantially continuous region of polymer composition extending through the web, with encapsulated web members above and below said region, leaving most of the interstitial spaces above and below said region open;
- and
- at least partially curing the polymer to provide a treated web with an effective pore size between about 0.025 and 100 microns.
Dependencies are inferred from the claim text.