US3413180A - Composite flexible porous sheet material - Google Patents

Description

Nov. 26, 1968 H. H. SMITH 3,413,180

COMPOSITE FLEXIBLE POROUS SHEET MATERIAL Filed June 12. 1964 G 3 a m/01% United States Patent "ice 3,413,180 COMPOSITE FLEXIBLE POROUS SHEET ABSTRACT OF THE DISCLOSURE A porous metallized fabric is disclosed which consists of a porous basic fabric having adhering to one surface thereof a thin sheet of metal which conforms to the surface contours of the basic fabric. The metal sheet is ruptured at. a suthcient number of the interstices of the basic fabric to give the required degree of porosity. The ruptured parts of the metal sheet extend inwardly of the respective interstices to conform to the wall contours thereof. A sheet of resilient material is bonded to the metallized fabric to produce a composite sheet with flexing properties which substantially reduce any tendency for the metal sheet to be locally displaced.

This invention concerns metallised fabrics.

Metallised fabrics are known, and have been used for various purposes. For example, metallised fabrics have been made by securing a continuous metal foil to a textile fabric by means of a suitable adhesive. Metallised fabrics have also been made by spraying textile fabrics with flaked metal particles suspended in a solution of a film-forming polymer. It is also known how to produce a metallised textile fabric by evaporating metal onto the cloth in vacuo. All these prior fabrics and proposals however suffer from disadvantages. One use for metallised fabrics is to afford protection for persons subject to substantial thermal radiation, and whilst a continuous metal foil, for example of aluminum has a very high reflectivity for such radiation, it is not porous and seriously interfers with the evaporation of water from the skin of the wearer. For this reason, clothing made from such metallised fabrics is not satisfactory as a protection from excessive themal radiation if worn for other than very short periods. Again, metallised fabrics made by spraying textile fabrics with flaked aluminuim particles suspended in a film-forming polymer have been found to have an emissivity for longwave infra-red radiation 'which is too high for many purposes. It does not appear that coatings of metal evaporated onto hydrophilic textile fibres are stable to moisture.

It has also been proposed to strengthen a metal foil by the application thereto of a woven or unwoven fabric of textile material or wholly or partly of wires, the foil and fabric being caused to adhere one to the other, with or without adhesive, by virtue of intimate contact produced between the foil and threads of the fabric by subjecting the foil to considerable pressure between the fabric and a layer of yieldable material such as rubber, said layer being a fiat web or the surface layer of a" pressure roll. The disclosure of the production and use of such a strengthened foil makes no reference to the production of a perforate foil and since the purpose to which the strengthened foil was to be applied, namely as a wrapping material for such as electrical conductors differs markedly from that of the material produced according to the present invention and quite different problems had to be considered, there is no reason to suppose that the strengthened foil is, in fact, perforate.

Patented Nov. 26, 1968 Recently, we developed a porous metallised fabric of the kind (hereinafter termed of the kind referred to) consisting of a porous basic fabric having adhering to at least one surface thereof, a thin sheet of metal which conforms to the surface contours of the basic fabric, and which is ruptured at a suflicient number of the interstices of the basic fabric to give the required degree of porosity, the ruptured parts of the metal sheet extending inwardly of the respective interstices to conform to the wall contours of the latter.

Such material may be made by causing the thin sheet of metal of adhere to at least one surface of the porous basic fabric by laying the sheet on the surface of the fabric and pressing into place by the direct application thereto of a resiliently deformable material, wherein the pressure applied is sufficient to cause the sheet to conform to the surface contours of the basic fabric and to rupture at a sufiicient number of the interstices of the fabric to give the required degree of porosity, and the rutpured parts of the sheet to extend inwardly of the respective interstices to conform to the wall contour of the latter.

We have now found that there is a tendency in certain end uses where such material is severely and continuously flexed or abraded, for localised disturbance and displacement of the metal sheet to occur. This disadvantage is particularly noiticea-ble when the basic fabric is itself thin and more particularly when the basic fabric has lines of freedom therein, as for example, in some Woven textile fabrics.

It is an object of the present invention to produce a porous metallised fabric, which overcomes, substantially, the disadvantage aforesaid.

The present invention is based on an appreciation of the possibility of overcoming substantially the disadvantage aforesaid, by bonding a sheet of resilient material to the metallised fabric, the resilient sheet having such thickness and properties as to produce a composite sheet with flexing properties which substantially reduce the tendency forthe metal sheet to be locally disturbed or displaced.

Thus, according to the present invention a composite sheet material comprises at least one layer of porous metallised fabric of Pthe kind referred to and at least one sheet of resilient material, which is bonded thereto over at least one surfacethereof, said resilient sheet having such thickness and properties as to modify the effect of flexing the composite sheet to an extent which is sufficient to reduce substantially the tendency for the metal sheet to be locally disturbed or displaced from the basic fabric when the composite sheet is flexed.

According to a preferred feature of the invention said resilient material is porous.

According to a further preferred feature of the invention, said porous resilient material comprises a natural or synthetic foamed plastic material of a kind having interconnected cells.

Preferably, when the metallised fabric comprises a basic fabric and a single thin metal sheet, the porous resilient sheet is bonded thereto on the face of the basic fabric remote from the metal sheet.

These and further features of the invention will be apparent from the following description, which concerns, by way of example only, the production of one form of composite sheet embodying the invention.

Of the drawings:

FIG. 1 shows a cross-section through the composite sheet;

FIG. 2 shows a schematic diagram of the apparatus used for the production of the composite sheet of FIG. 1; and

FIG. 3 shows a cross-section through a modification of the composite sheet.

Referring now to FIG. 1, the composite sheet comprises a basic fabric consisting of a woven continuous filament viscose rayon weighing two and a half ounces per square yard, an aluminium foil 11 having a thickness of 0.00025 inch, and a foamed polyester sheet 12 having a thickness of one sixteenth of an inch. The three layers 10 to 12 are bonded together at their interfaces by suitable adhesive compositions, and the aluminium foil 11 is ruptured at suflicient of the interstices of the basic fabric 10 to give the composite sheet a desired porosity.

Referring now to FIG. 2, one manner for producing the composite sheet will be described.

Use is made of a calender or mangle comprising a hard bowl or roller 16 working against a bowl or roller 17 covered with moderately soft rubber e.g. 34 BS. degree hardness and of a thickness of about one sixteenth of an inch. A continuous sheet of thin aluminum foil 11 is coated on one face with a thin layer of an adhesive 18 by being drawn through a roller coater mechanism 19 with doctor knife attachment 20 and is then fed into the calender or mangle together with the fabric 10 to be coated, which is also in continuous length. The uncoated face of the aluminium foil is in contact with the rubber-coated bowl or roller 17 of the calender or mangle and the coated face of the foil is in contact with one face of the fabric, the other face of the fabric being in contact with the hard bowl or roller 16 of the calender or mangle. If desired, the hard bowl or roller of the calender or mangle may be heated (for example by feeding steam thereto) to assist in fixing the adhesive.

The aluminium foil 11 is thus bonded to the upper face of the fabric 10 and is ruptured at the interstices thereof, by the pressure of the rubber covered roller 17 a pressure of about 1.4 tons per square inch being applied to the foil and basic fabric at the mangle 16, 17 for this purpose.

The basic fabric with the foil bonded thereto is then passed through a further roller coater mechanism 21 where the face of the basic fabric 10 remote from the foil 11 is coated with adhesive 22. A polyester foam sheet 12 is then brought into pressurized engagement with the coated face of the basic fabric 10 and is bonded thereto by calender rolls 23.

The composite sheet which emerges from the calenders 23 may be subjected to drying or other after treatment to fix the adhesives if desired or necessary.

The composite sheet described and produced by the method indicated retains the remarkable properties of our metallised fabrics of the kind referred to but can be continuously and severely flexed without any appreciable tendency for the aluminium foil to be disturbed or displaced from the surface of the basic fabric.

It will be appreciated that it is not intended to limit the scope of the invention to the above examples only, many variations, such as might readily occur to one skilled in the art being possible without departing from the principles of the invention.

Thus, for example, the metal may be bonded to the basic fabric by other means, and the metal may be applied to both sides of the basic fabric if desired. The metal may be other than aluminium, and the basic fabric may be of other form and/or of other material. The resilient layer which need not be porous may be of different material, for example, polyurethane foam, and two layers of such may be incorporated in the composite sheet if desired. In addition, a backing fabric for outwardly direct surfaces of the resilient layer or layers may be provided if desired. This latter modification is shown in FIG. 3

4 which is similar to FIG. 1 with the addition of the backing fabric 24.

It is envisaged that composite sheets according to the invention will find many uses, in the production of for example, special protective clothing including space-suits, rainwear and other more conventional garments, shoes, tents and other camping equipment, cinematograph screens, electrical and electronic components and equip ment, radar equipment, building sheets such as wall coverings, and so on.

It will be appreciated that the composite sheet when formed with a layer of foam has good heat reflecting properties as well as low heat conduction properties, making use as a thermal insulating material particularly attractive for certain application.

The various layers of the composite sheet may of course be bonded at their interfaces other than by use of adhesive compositions. Thus, for example, a polyester foam layer may be bonded to a textile fabric by a heating technique or by other known processes.

I claim:

1. A composite flexible porous sheet material for use in an article of protecting clothing comprising at least one layer of porous metallized fabric consisting of a porous basic fabric having adherent to at least one surface thereof a thin sheet of metal, the basic fabric having a plurality of interstices to impart porosity to said fabric, said thin sheet of metalconforming to the surface contours of the basic fabric and being ruptured at at least a substantial number of said interstices of the basic fabric to give said metallized fabric porosity, the ruptured parts of the metal sheets extending inwardly of the respective interstices to conform to the wall contours of the interstices, and at least one sheet of porous resilient material having interconnected cells and being selected from the group consisting of natural and synthetic foamed plastic materials, said resilient material being bonded to said porous metallized fabric on the face of the basic fabric opposite said metal sheet whereby said thin sheet of metal resists being locally disturbed or displaced from said basic fabric when the composite sheet is flexed.

2. A composite sheet material according to claim 1 wherein said foamed material consists of a polyester foam.

3. A composite sheet material according to claim 1 including a sheet of textile fabric which is bonded to the surface of said resilient material opposite said basic fabric.

4. A composite sheet material according to claim 1 wherein said thin metal sheet consists of aluminium.

5. A composite sheet material according to claim 4 wherein said metal sheet is about 0.00025 of an inch thick.

References Cited UNITED STATES PATENTS 2,003,494 6/1935 Reynolds 161-114 2,492,143 12/1949 Gipple etal 51-195 2,728,702 12/1955 Simon et a1. 161-213 x 2,961,418 11/1960 Wilson et a1. 260-25 3,034,940 5/1962 Collins 8! al. 161-89 3,240,855 3/1966 Voelker 156-254x FOREIGN PATENTS 804,187 11/1958 Great Britain.

ROBERT F. BURNETT, Primary Examiner.

R. L. MAY, Assistant Examiner.

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