WO1993008024A2

WO1993008024A2 - Protective material

Info

Publication number: WO1993008024A2
Application number: PCT/GB1992/001870
Authority: WO
Inventors: Craig Barson; Stephen John Hill; John Keith Walton
Original assignee: Freudenberg Nonwovens Ltd.
Priority date: 1991-10-15
Filing date: 1992-10-12
Publication date: 1993-04-29
Also published as: GB9407242D0; GB9121868D0; GB2276121A; WO1993008024A3; AU2695592A

Abstract

A composite, suitable for use as a protective material, comprising, adhesively-bonded together, in order: (1) a combination of an outer microporous membrane and a non-woven fabric; (2) an intermediate layer including activated carbon; and (3) an inner layer adapted to contact the skin.

Description

PROTECTIVE MATERIAL Field of the Invention

This invention relates to protective material and especially to garments intended to be worn as protection from contaminated environments. Background of the Invention

For satisfactory performance, protective clothing materials must fulfil two, contradictory criteria. Firstly, they must afford the wearer maximum possible protection against a variety of external chemical and biological agents. Secondly, for the comfort of the wearer, they must be outwardly permeable to air and water vapour as well as being flexible and light.

Impermeable materials such as rubber provide complete protection, but do not meet the second criterion. A compromise between total protection and effectiveness must be made. An alternative to total protection is to use a means of filtration of chemical liquids and vapour, e.g. activated carbon (see GB-A-1127581, GB-A-2096836, GB-A- 2137608 and GB-A-2199787) .

Many of the earlier approaches to developing a protecting clothing system were limited by various factors, including the strike-through of woven fabrics by droplets of toxic chemicals, the low tear strength of simple non- woven fabrics and the degradation of the activated carbon under wet or dry conditions.

GB-A-2096536 describes a composite protective material comprising a two-layer cloth structure, one layer being oil/water-repellent and the other being an adsorptive charcoal. For use as a protective material, four layers are required. The innermost layer is moisture-absorbent, but will not prevent sweat poisoning.

GB-A-1127581 discloses a composite of a woven or knitted fabric and a non-woven fabric, impregnated with a binder and having a layer of charcoal bonded to one side.

GB-A-2199787 discloses a two-ply protective material, the first ply comprising a fire-retardant fabric bonded to a microporous material, and an inner ply of charcoal bonded by synthetic rubber. Summary of the Invention

According to a first aspect of the present invention, a composite suitable for use as a protective material comprises, adhesively-bonded together, in order:

(1) a combination of an outer microporous membrane and a non-woven fabric;

(2) an intermediate layer including activated carbon; and

(3) an inner layer adapted to contact the skin. According to a second aspect of the present invention, a one-piece article of protective clothing is produced by applying one or more of the respective components of a composite protective material onto an inner fabric and/or a former.

According to a third aspect of the present invention, an article of protective clothing has an elasticated aperture treated with activated carbon. Clothing incorporating composite material of the invention offers a high level of protection together with a low physiological load upon the wearer. Detailed Description of the Invention

The layers of the composite material may be joined together by means of thermoplastic adhesive webs. Two or more respective layers may carry a discontinuous coating of a thermoplastic material, the layers then being bonded by the application of heat and pressure. This can be achieved without sacrificing the product's handle and flexibility. The material of the outer layer comprises a non-woven fabric and, preferably laminated thereto, a microporous membrane, e.g. of polyurethane. Instead of a laminate, the microporous layer and non-woven may be separate. This may provide more comfort/tactility to the glove, although the microporous layer might be more vulnerable to damage.

The microporous membrane may be of the type described in GB-A-2199787. The membrane does not inhibit breathability, but provides a barrier to penetration by liquid chemical agents. Upon initial contact with the outer layer, any droplets will be shed by the polyurethane membrane or will tend to spread in the non-woven fabric. Hence, only vapour will penetrate through to the carbon layer, thereby reducing the danger of saturating the active carbon layer and, with it, losing the potential for absorption.

The intermediate layer serves to adsorb poisonous vapours that may penetrate through the outer layer. It allows the inward passage of air and the outward transmission of water vapour. This layer preferably includes activated carbon in the form of a powder. The activated carbon may, for example, be borne on a foam or on a non-woven fabric.

The inner layer acts as a lining material. It is, for example, of cotton, and may be woven or non-woven. Its bonding to the intermediate layer should not affect the adsorptive properties or stability of the activated carbon. Composite material according to the invention may be made up into an article of protective clothing, i.e. one or more components of a complete body cover, e.g. glove or hood, a casualty bag or protective suiting.

Composite material according to the invention stands up well to the challenge of mustard gas, both on garments as a whole and also at sewn seams. As an alternative to sewing, however, an article of clothing may be prepared by spraying activated carbon, or the material of respective layers, onto a former, or onto a formed fabric that serves as an inner layer for the article. An alternative to spraying, e.g. using a robotic arm carrying a spray gun, is to dip the former or formed fabric into a carbon-containing binder formulation. The product is a one-piece article, without seams. If the outer laminate materials are not applied by spraying, dipping or other means, the laminate or its materials may be applied independently. In order that an aperture in a garment should not compromise the barrier against contamination by biological or chemical agents, an elasticated material may be incorporated into the garment aperture or in a strip adapted to be attached thereto. This elastication will afford the garment close contact with the wearer or another garment. It is a preferred feature of this invention that the elastic material, or the strip or the garment around the aperture, is treated with activated carbon. This can be done at any stage during the manufacture of the article, and can be incorporated into a spraying procedure.

By way of example, the garment material comprises essentially three layers. The two outer layers are carbon impregnated/sprayed fabric of lightweight material. The central layer is a piece of elastic material, e.g. rubber or polyurethane etc. The three layers are brought together, with the outer layers pleated, and are joined together, e.g. using adhesives, heat-welding or sewing, to form a stable multilayer strip. The elastic strip will stretch and the normally inextensible layers of carbon- containing material of, e.g. non-woven, woven or knitted material, can also extend until all the pleats are removed. Such a material may be used as a wrist closure: the tension in the elastic material would force the outer layers flat and present a good seal.

This arrangement is schematically illustrated in Figure 1 which shows pleated outer layers A and B and an elastic inner layer C. A more refined arrangement is shown in. the top view of Figure 2 , comprising two A's (illustrated as Al and A2) and B's each off-set by the frequency of attachment,. so that if contaminant were to pass through one of the apertures it would encounter a more tortuous passage through the seal.

Such a strip is, for example 10 to 50 mm wide. It may be attached to a garment by sewing or some other conventional technique.

Claims

1. A composite, suitable for use as a protective material, comprising, adhesively-bonded together, in order:

(1) a combination of an outer microporous membrane and a non-woven fabric;

(2) an intermediate layer including activated carbon; and

(3) an inner layer adapted to contact the skin.

2. A composite material according to claim 1, wherein the microporous membrane comprises polyurethane.

3. A composite material according to claim 1 or claim 2, wherein the intermediate layer comprises a foam bearing activated carbon powder.

4. A composite material according to claim 1 or claim 2, wherein the intermediate layer comprises a non-woven fabric bearing activated carbon powder.

5. A composite material according to any preceding claim, wherein component (1) is a laminate of the membrane and the fabric.

6. A composite material according to any preceding claim, which additionally comprises an outer, wear layer.

7. A composite material according to claim 6, wherein the wear layer is laminated to the membrane.

8. An article of protective clothing which comprises composite material according to any preceding claim.

9. A one-piece article of protective clothing, as produced by spraying the respective components of a composite protective material onto an inner fabric and/or a former.

10. An article according to claim 9, wherein the composite material thus produced is as defined in any of claims 1 to 5.

11. An article of protective clothing having an elasticated aperture treated with activated carbon.

12. An article according to any of claims 8 to 11, which is in the form of a glove.