Laminates of chitosan films
Chitosan films and laminates made from the films are provided. The films and laminates can be used to make a variety of finished articles that can be used to provide protection from hazardous chemical and biological agents.
1. A finished article comprising a laminate comprising:
(a) an insoluble continuous chitosan film,
(b) a substrate onto which the chitosan film is adhered, and
(c) at least one layer of fabric, wherein: the continuous chitosan film and a layer of fabric are bonded discontinuously using an adhesive that is present as an array of adhesive dots, in a pattern of lines or in a pattern of curves, the substrate comprises a film comprising a polar polymer or a sheet comprising a polar polymer, wherein the polar polymer is an elastomer, glassy polymer, or semi-crystalline material, and wherein the substrate is incorporated into the laminate, and the fabric is woven or nonwoven and comprises one or more members selected from the group consisting of aramids, polybenzimidazoles, nylons, polyesters, and cotton, said article being chemically protective and selectively permeable to water vapor such that:
the Moisture Vapor Transport Rate is at least 2 kg/m 2 /24 h,
the transport rate is <4.0 μg/cm 2 one hour cumulative permeation for mustard, and
the transport rate is <1.25 μg/cm 2 one hour cumulative permeation for Soman, wherein the finished article is selected from the group consisting of:
items of apparel selected from the group consisting of coveralls, protective suits, coats, jackets, raingear, ski pants, gloves, socks, boots, shoe covers, boot covers, trousers, hoods, hats, masks, and shirts; shelters; and protective covers.
2. The finished article according to claim 1 wherein the chitosan film further comprises one or more members selected from the group consisting of natural polymers, synthetic polymers, crosslinking agents, fillers, flame retardants, plasticizers, tougheners, and stabilizers, and wherein the film comprises at least 50% chitosan by weight.
3. The finished article according to claim 1 wherein the substrate is essentially without protrusions above the plane of the substrate that are higher than the desired thickness of a coating of chitosan solution that will be transformed into the chitosan film.
4. The finished article according to claim 1 wherein the polar polymer is selected from the group consisting of perfluorosulfonic acid tetrafluoroethylene copolymers, polyurethanes, polyether block polyamide copolymers, polyether block polyester copolymers, sulfonated styrene-polyolefin di- and tri-block copolymers, and polyvinyl alcohol homopolymers and copolymers.
5. The finished article according to claim 1 comprising an outer shell, and optionally an inner liner, each independently comprising at least one member of the group consisting of woven fabric and nonwoven fabric.
6. The finished article according to claim 5 wherein the woven or nonwoven fabric comprises one or more members selected from the group consisting of aramid, polybenzimidazole, nylon, polyesters, and cotton.
7. The finished article according to claim 1 further comprising at least one additional layer.