Fabrics for protective garments having strands of reflective materials

Protective fabrics having a reflective surface are made of textile yarns, for example of wool, intermeshed with strands of reflective material, for example a metallized plastics film, a major proportion of the textile yarns being present in one face of the fabric and a major proportion of the reflective strands in the other. The fabric may be woven, for example on a double beam loom, or knitted, as on a double jersey machine. ,he preferred reflective strand is a laminate of aluminium between two polyester films, split into widths between 0.3 and 0.8 mm.

This invention relates to protective fabrics and more particularly to 
fabrics having a reflective surface. 
Protective garments for persons working in close proximity to fire and 
other heat sources often have reflective outer surfaces to reflect as 
large a portion as possible of the incident radiant heat. Two methods have 
been proposed for producing such fabrics. The first involves laminating a 
sheet of bright metal to a fabric using standard lamination techniques; 
the second method is to metallise one surface of a fabric by vapour 
deposition of a suitable metal, e.g. aluminium. 
The fabrics produced by both of these prior techniques suffer from various 
defects, the principal of these being stiffness and lack of permeability. 
Thus both types of fabric are uncomfortable to wear for long periods. 
Since garments of protective fabrics have to be worn by a wide variety of 
people, e.g. metal workers, furnacemen, ship-builders, firemen and welders 
in appropriate conditions, it would obviously be desirable to have a 
protective fabric from which garments could be made that would be 
comfortable over extended periods of wear. 
The invention seeks to provide a fabric which is permeable, is less stiff 
than the above-described prior fabrics, and may be made in lighter weights 
without losing effectiveness of protection. 
According to the invention there is provided a fabric composed of textile 
yarns intermeshed with strands of reflective materials, in which a major 
proportion of the textile yarns are present in one face of the fabric and 
a major proportion of the reflective strands are present in the other face 
of the fabric. 
The fabric may be produced by weaving or knitting. For example, double beam 
weaving or weaving to obtain a double-faced fabric may be employed or the 
fabric may be knitted on a double jersey knitting machine, preferably 
interlock gated. However, for most end-uses a woven fabric is preferred, 
and therefore we prefer to make the fabric using a double beam weaving 
method. 
The textile yarns used affect the comfort, appearance and fire resistance 
of the finished fabric. Any known textile yarn, filament or strand may be 
employed, for example using polyamide, polyester, acrylic, regenerated 
cellulosic, polyalkylene, or vinyl filaments or fibres. Natural fibres 
such as cotton or linen may also be employed, but it is preferred to use 
yarns of keratinous fibres, especially wool, on account of their superior 
comfort, drape and flame-retardant properties. 
For the reflective strand, metal or metallised yarns, filaments or strands 
may be used, for example stainless steel or copper fibres. However it is 
preferred to use aluminised threads of cotton or polyester, and in 
particular strands produced by sandwiching a film (typically 1 or 2 
microns thick) of aluminium between two polyester films, and splitting the 
laminate into tapes of any desired width. Tapes of width between 0.3 and 
0.8 mm have been found optimum for most purposes; below 0.3 mm the 
strength of the tape is too low to withstand the stresses of weaving or 
knitting; above 0.8 mm it is too wide and the cloth produced is 
unsatisfactory, e.g. the tapes tend to buckle at the interlacings of the 
weave. About 0.4 mm is the preferred thickness. 
The woven fabric may be made using reflective strands in the weft only but 
for an especially high degree of reflectance we prefer to use reflective 
strands in both the warp and the weft. 
As mentioned previously, it is preferred to use wool yarns as the textile 
component because, inter alia, of wool's natural flame retardance. This 
may be improved even further by treatment with anionic complexes of 
titanium or zirconium according to the process of our U.K. Patent Nos. 
1,372,694 and 1,379,752. It is preferred to carry out either of these 
processes on the wool yarns before weaving into the fabric of the 
invention to prevent any possible adverse effect on the reflective 
component of the fabric.

Referring to the drawings, as is well understood in the art, the 8.times.8 
square boxes 10 boldly outlined show the pattern in which the fabric is 
woven. Shaded squares 12 indicate that the warp yarn passes over the weft 
yarn; and blank squares 14 indicate that the weft yarn passes over the 
warp yarn. In FIG. 1 the blank squares below the box 10 indicate that all 
eight warp yarns in the pattern unit are textile yarns 16. The weft yarns 
are indicated to the right of the box 10 and it can be seen that in FIG. 1 
alternate weft yarns are textile yarns 16 (blank squares) and aluminium 
yarns 18 (lined squares). In FIGS. 2 to 4 there are alternate aluminium 
yarns 18 in the wool also. 
The following examples, described with reference to the accompanying 
drawings showing four fabric patterns, will illustrate the invention 
further. 
EXAMPLE 1--Aluminium inweft only 
Since high strength and extension is required in the warp thread for 
satisfactory weaving, a fabric using aluminium in the weft only was tried 
to ascertain whether it would give substantial thermal protection. 
2/32's wool yarn was used in the warp and in alternate weft picks with 0.37 
mm aluminium tape. The fabric was a 2.times.2 twill with a weft back and 
is shown in FIG. 1. 
Protection against thermal radiation was measured by a method similar to 
the British Standard 3791 in which a fabric sample is held in an assembly 
to measure the temperature of the back of the fabric when placed 20 cm 
away from a gas-fired radiant panel at a black body equivalent temperature 
of 660.degree. C. The results are given in TPI Thermal Protection Index 
(radiation) which is a number equal to the time in seconds before the 
temperature of the back surface of the sample rises 25.degree. C. 
The TPI (radiation) of the experimental fabric was 17 compared to the TPI 
(radiation) of a standard commercial aluminised wool laminate of 34. This 
result, although superior to material containing no metal strands, could 
be improved by using aluminium tape in both warp and weft. 
EXAMPLES 2 and 3--Aluminium in warp and in weft 
To increase the heat reflective cover of the face of the fabric, aluminium 
tape was used both in the warp and in the weft. Two types of design were 
investigated. FIG. 2 shows a plain back structure and FIG. 3 a twill back 
structure. FIG. 4 shows the reverse face of FIG. 3. 
The plain back structure was lighter in weight and was thinner than the 
twill back structure. The TPI (radiation) values for these two fabrics 
were 34 and 45 for the plain and the twill back structures respectively. 
(The TPI of laminated aluminised fabric 420 g.m..sup.-2 used as a standard 
was 37). Fabric details are given in Table I. 
TABLE I 
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Fabric Details 
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Wool Yarn R55 tex/2 (2/32's worsted) 
Aluminum Tape 
R26 tex (0.37 mm) 
Reed Setting 36 inch 
Ends/inch 120 
Alternate wool and aluminium 
Picks/inch 100strands 
Fabric width 33.5 inch 
Fabric Weight 
360 g.m..sup.-2 
Blend composition 
68% wool/32% Aluminium 
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The woven fabric does not require wet finishing and the only finishing 
treatment envisaged is a demi-decating process under high wrapper tension. 
Besides the thermal protective index (radiation) tests reported above, the 
fabrics were tested for snagging on the I.C.I. Mace Test and for 
dimensional stability of the fabric using a "Cubex" test washing machine 
(15 minute agitation time in 15 liters of phosphate buffer solution at pH 
7) 
The snag rating was 4 (5 is excellent) and the fabric shrinkage was less 
than 3% in any direction.