FR2831773A1 - Multilayer sheet material for protective clothing, especially for firemen, has a double external layer which shrinks when exposed to heat, with pockets between layers formed by linking selected threads - Google Patents

Abstract

Multilayer sheet material for fireproof protective clothing has a double external layer comprising a layer which undergoes shrinkage when exposed to heat, with interlayer pockets formed by intermittently linking selected threads in the two layers. Complex multilayer sheet material for protective clothing, especially for fire fighters, with an external fabric/thermal barrier comprising first and second layers, is made by weaving or knitting so as to form a double-faced, superimposed structure (1, 2) bound together intermittently to form pockets, with one layer showing shrinkage when heated and the connection between the layers being formed by intermittent linkage of a selection of threads to form these pockets.

Description

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MULTILAYERED SHEET COMPLEX MATERIAL FOR USE
FOR THE PRODUCTION OF PROTECTIVE CLOTHING,
ESPECIALLY FOR FIREFIGHTERS.

Technical area
The present invention relates to fabrics, in sheet or tablecloth, usable for the production of complex materials intended to produce protective clothing, in particular jackets for intervention of persons who may be subjected to extreme conditions, in particular in the case of fire. .

 It relates in particular to a new type of material that can be used to make firefighters' clothing, without excluding other applications.

Previous techniques
In the following description, the invention will be described for a particular application, namely that of making intervention jackets for firefighters.

 It is obvious that this is not limiting and that such a material could be used for other applications, and in all cases where one is in the presence of extreme conditions, for example during a fire.

 To date, to make intervention jackets, multilayer structures are used which, in general, as shown in Figure 1 attached, generally consist of four elements, namely: an external fabric ( AT) ; a waterproof-breathable membrane, generally associated with a substrate (B); a thermal barrier generally constituted by a needle felt (C); and a finishing lining (D).

 The production of such complex materials which can be used under extreme conditions is perfectly known to a person skilled in the art and is apparent in particular from French patent 1,213,415.

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 Since then, such structures have evolved using in particular textile materials resistant to heat and fire, based on aromatic polyamide or polyamide imide.

 Among these most known synthetic materials, mention may be made, in the family of aromatic polyamides, of para-aramid threads or fibers, as marketed by the company DU PONT DE NEMOURS under the name "KEVLAR" or by the company TEIJIN under the TTARCW and TECHNORM brands. Such polymers, which can therefore be in the form of fibers, threads, or other structures, have been the subject of numerous publications among which mention may be made of US Pat. No. 3,063,966.

 Among the materials which are also heat resistant, and which are part of the meta-aramid family, there may be mentioned the polymer marketed by the company KERNIEL under the same name, and the fibers marketed under the brand 7VOMELY by the company DUPONT DE NEMOURS and those marketed under the CONEX brand by TEIJIN.

 As indicated above, the invention therefore relates to the sector of the production of multilayer materials as illustrated in FIG. 1.

 In these materials, a problem arises with regard to the thermal barrier, generally constituted by a needled felt, and the finishing lining situated on the side of the user.

 Indeed, the complexes proposed to date have a drawback which essentially resides in the fact that the clothes produced lack comfort both physically and physiologically.

 In addition, under certain conditions, they lack efficiency.

dans le domaine par le terme"e fAe/Me", qui est un état dans lequel le corps ne peut plus maintenir une température en dessous de 39 C, ce qui entraîne des troubles Indeed, it has been reported that approximately 50% of the causes of death for firefighters operating in the United States, are the consequence of a well-known phenomenon

in the field by the term "e fAe / Me", which is a state in which the body can no longer maintain a temperature below 39 C, which leads to disorders

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 various may be, in addition to a loss of physical capacity, a loss of lucidity, fainting or even cardiac arrest.

 Such a state of stress is caused, in particular by the weight of the equipment which can exceed 20 kilos, as well as the sometimes too insulating capacity of their protective clothing.

Statement of the Invention
Now it has been found, and this is the subject of the present invention, that it was possible to solve this problem by means of a new type of material making it possible to produce not only the external fabric resistant to heat entering into the constitution of complexes, but which can also fulfill a thermal barrier function making it possible to eliminate the use of needled felt generally used today.

plus forte dans le cas d'une situation d'urgence face au feu. c
D'une manière générale, une telle possibilité est obtenue conformément au matériau selon l'invention, en réalisant un complexe remplissant les fonctions à la fois de tissu extérieur et de barrière thermique, en faisant appel à une technique de réalisation d'étoffes tissées, technique connue sous la dénomination tissage de tissus "poche"ou de double étoffe liée. This new type of complex, which will be called by the expression "outer fabric-double reactive fabric, allows moderate insulation in normal situation by the fact that it has a low thickness and a low thermal load, which improves it. therefore comfort and which, depending on the increase in temperature, allows to have an increase in insulation, located at the place where the heat is the

stronger in the event of a fire emergency. vs
In general, such a possibility is obtained in accordance with the material according to the invention, by producing a complex fulfilling the functions of both external fabric and thermal barrier, by using a technique for producing woven fabrics, technique known under the name weaving of "pocket" fabrics or of double linked fabric.

 Such a technology consists in producing in a single operation, two (or more), separate and superimposed fabrics, which are connected together by a selection of threads (warp or weft) which link alternately, according to a predetermined selection, with one either armor of the two superimposed fabrics.

 As an indication, a warp thread on the upper face can, according to a predetermined sequence, be linked with a weft (or pick) on the lower face. This link can

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 be done according to any type of pattern, conventionally to form diamonds or tubes. Generally, during the connection, the reverse and reverse sides of different colors are reversed to obtain a decorative effect, which is not desirable in the context of the invention where each face must have a specific function.

 Optionally, such double-sided structures can also be produced by knitting, either according to the picked mesh technique or according to the discarded mesh technique, more particularly on looms of the warp or Rachel knitting type.

 According to another embodiment of the invention, it is possible to obtain a structure of this type by the technology known under the name of double-wall weaving with a connecting thread connecting the two faces creating a spacing between said faces. We prefer a reduced pile length for good fabric hold and an optimal thermal reaction effect.

 In general and taking into account the problem posed of producing an exterior fabric / thermal barrier in the case of protection, in particular for firefighters, with the aim of improving the comfort of said clothing, both physically and physiologically, it was designed according to the invention a complex multilayer material in sheets making it possible to produce a thermal barrier composed of a first and a second layer, characterized in that it is produced by weaving or knitting, so as to form a structure double face (1,2) superimposed, intermittently connected together so as to form pockets, and in which: one of the layers shrinks under the effect of heat; 'The connection between the layers is carried out by intermittent bonding of a selection of threads to form said pockets.

 According to a preferred embodiment, the layer intended to form the internal face consists entirely or in part of para-aramid yarns or fibers or PBO, while the layer intended to form the external face consists entirely or in part of meta-aramid-type yarns or fibers.

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Brief description of the drawings
The invention and the advantages which it provides will however be better understood thanks to the following description of an example of a complex in accordance with the invention and which is illustrated by the appended diagrams in which:
FIG. 1 illustrates, as indicated previously, a conventional multilayer complex used to date for the production of clothing for intervention personnel under risk conditions, in particular clothing for firefighters;
FIG. 2 is a schematic perspective view showing an example of the structure of a complex according to the invention making it possible to simultaneously produce the external face (fabric A) and the thermal barrier (C) of a multilayer structure entering the production of protective clothing, in particular firefighter jackets;
Figure 3 is a schematic sectional view of a material according to the invention when the user is in normal working conditions;
Figures 4 and 5 illustrate, seen in section and in perspective, schematically, the evolution of the complex according to the invention when the user is faced with a sudden change in operating conditions, and more particularly a sudden increase heat ;
FIG. 6 illustrates, in a conventional manner, on the one hand, as can be seen from the view on the left, a double-sided fabric in accordance with the invention, and on the other hand, seen from the right, the fabric obtained on the right side , external face when the complex is used;
FIG. 7 is a conventional representation showing, seen in warp direction section, the work of the plies of warp yarns relative to the weft yarns, in order to constitute a double face fabric of pocket type, said faces being linked together in a sequence predetermined.

 Figure 8 shows the armor diagram for the production of diamond-shaped pockets.

 Referring to Figures 2 and 3 attached, the basic structure according to the invention is therefore constituted by a pocket fabric comprising an outer layer designated by the general reference (1), an inner layer, designated by the general reference (2 ), these two layers being joined to one another and being linked together, by

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intermittently, by a selection of warp threads (3), threads selected from those constituting the outer layer.

In other words, in such a structure, the connecting lines (3) form, 1 between them, flat tubes formed between the outer layer (1) and the inner layer (2).

From a practical point of view, and as can be seen more particularly from FIG. 2, the warp threads (CI) intended to form the outer layer (1), as well as the weft threads (Tl), consist of threads , and more particularly of yarns of fibers having a reduced shrinking power under the effect of intense heat.

Such yarns will preferably be yarns of fibers made up of a mixture of c meta-aramid fibers and antistatic fibers, these fibers being designated by the reference (K) in FIG. 6.

 The warp threads (C2) and the weft threads (T2) intended to constitute the internal layer, that is to say the insulating layer when the material is used, are made up. by wires which have practically no shrinking power compared to the wires (Cl) and (Tl).

These yarns are preferably yarns selected from the paraaramid or PBO family.

In the concrete example represented in FIG. 2, the density of warp (C2) c and weft (T2) yarns is equal to that (Cl) and (Tl) of the other face.

 Thanks to such a structure, the fact of using slightly heat-shrinkable wires for the outer layer makes it possible to obtain heat shrinkage as illustrated in FIG. 4.

 In fact, when the temperature reached by the external face (1) is sufficiently high, for example in the case of the use of meta-aramid yarns of the KERMEL type, and is of the order of 300 C, there is a retraction of these wires which will have the effect

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 to bring the generators closer to the flat tubes. As the internal face is dimensionally stable to heat, this will create "slack" on the lower side, and therefore raised tubes.

 It should be noted that even if (C2) and / or (T2) were made of materials having a shrinking power, the fact that they are protected by the face (1) would create a temperature differential seen by the two faces and therefore a shrinkage differential creating the pockets in relief.

 These spaces are increased as the temperature rises, which will increase the thickness of the fabric (air trapping) and therefore increase its insulating capacity.

dont l'armure de tissage est illustrée par la figure 6. Example:
A complex is produced in accordance with the invention, of the type illustrated in FIG. 2, and

whose weaving weave is illustrated in FIG. 6.

1 1-1
The external warp (CI) and the external weft (Tl), intended to form the external face of the complex structure produced during use, are produced from a spun of mixed fibers based on meta-aramid fibers ( KERMEL) and anti-static fibers.

 The title of these threads is Nm 70/2.

 The density of warp threads is 26 threads / cm and the weft density of 24 picks / cm.

 The warp (C2) and the weft (T2) are made up of a spun of para-aramid-based fibers.

 The title of these threads is Nm 70/2.

 The weaving is carried out at the rate of 26 warp threads per centimeter and 24 wefts (picks) per centimeter.

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 The upper face, which will therefore be turned towards the outside of the garment, will therefore consist entirely of yarns based on a mixture of meta-aramid and antistatic fibers.

 The binding of the two fabrics formed is obtained by making warp threads (CI) work with a weft threads (T2) of the ply (2) according to a determined sequence.

 The basic weave of the threads is a canvas type weave.

2 300 g/m2. When the loom falls, such a "pocket" fabric has a surface mass of approximately

2,300 g / m2.

1-1 Implementation of the Invention
A multilayer structure is produced from the material according to the invention which, compared with that of the prior art illustrated in FIG. 1, consists, for example: - of an outer fabric produced in accordance with invention, and therefore in the form of a double-bonded fabric; - a second layer constituted by a waterproof-breathable membrane associated with an aramid nonwoven based on fibers; - a lining made up of a conventional fabric, made from meta-aramid (KERMEL) / Viscose yarns.

 It is noted that in such a complex, there is therefore no thermal insulation layer compared to the composite structures of the prior art.

 The connection of the different layers to each other is carried out by any known and appropriate means.

 After having subjected such a complex to tests making it possible to determine the protection values obtained, according to standards EN 366 and EN 367, it is therefore found

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 that the protection values obtained are quite high, but, what is more remarkable, we note that the typical values "leak time", that is to say the differences between the theoretical burn times (t2 or HTI 24 ) and the theoretical pain times (tl or HTI 12), are actually higher than the average generally observed for conventional complexes.

 In particular, this separation of times (tl) and (t2) results from the fact that the complex reacts (increase in thickness) between the moment when the pain threshold is reached (tl) and the moment when the pain is reached. theoretical second-degree burn time (t2). Its level of protection increases with exposure time.

The material according to the invention makes it possible to produce complex structures resulting in moderate insulation in a normal situation by the fact that it does not comprise a layer constituting a thermal barrier, which makes it possible to obtain a structure having a smaller thickness, and consequently a lower thermal load (less heat to wear)
This therefore makes it possible to make more comfortable clothing, while offering good level of insulation and localized in places where the heat is strongest in an emergency situation (type "fire face").

 Furthermore, such a material makes it possible to visualize the degree of degradation of the material.

 Indeed, if the garment has reliefs, this means that the material has therefore been degraded and that said garment is no longer reliable. It should be noted that the case where the structure according to the invention will react does not correspond to normal use, but rather to an exceptional situation. It is therefore not a material allowing the production of a penetrating garment, whose role is exclusively to allow entry into the fire.

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 In addition, when the temperature level is such that there has been a reaction of the outer layer, the membrane located behind this layer is also damaged, which requires the disposal of the garment.

 The perception of the danger is also improved by the fact that this type of complex gradually adapts its level of insulation as a function of the thermal danger.

 It can be added that this complex does not present the problems of aging of conventional needled felts (migration of fibers, compaction, etc.), nor the problems of abrasion undergone or created by thermal barriers present a permanent relief.

 Another advantage of the structure in accordance with the invention is that it allows an optimal combination of meta-aramid and para-aramid materials, which each have their qualities and defects.

 Para-aramid is very resistant, very dimensionally stable in flame and remains flexible and resistant even when subjected to intense heat for a fairly long time (thermostability). Its main defects are very rapid aging with Ultra-Violet (UV) radiation, very poor color fastness (fibrillation resulting in intense belaying), and poor abrasion resistance (transverse resistance of the fiber).

 This combination according to the invention allows total protection of paraaramid against the action of UV, as well as good abrasion resistance, and therefore makes it possible to have only the meta-aramid-based layer on the visible face. which poses far fewer problems of aging and appearance.

 In the case of pockets in the form of channels in the double fabric according to the invention, these will preferably be arranged vertically in the garment in order to prevent the slight perpendicular retraction from going up the bottom of the jacket and the sleeves . This slight tightening of the layer in question on the body of the wearer is not problematic, because there is in fact a redistribution of the protective air contained

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 in the garment by automatically favoring the places where the heat is punctually the highest.

 Of course, the invention is not limited to the concrete example described above, but it covers all the variants produced in the same spirit.

 For example, a choice of diamond-shaped pockets may prove to be more advantageous than the channels in the sense that if the retraction of the external face is done in both warp and weft directions, there is controlled relief formation in both directions. We refer to the example of diamond armor (Figure 8). The warp thread on the external face hooks a pick on the internal face when it passes under two picks on the external face in order to make this hooking point invisible.

Claims (6)

 CLAIMS 11 Complex multilayer sheet material usable for the production of protective clothing, in particular for firefighters, and making it possible to produce an external fabric / thermal barrier composed of a first and a second layer for the production of such clothing, characterized in that it is produced by weaving or knitting, so as to form a double-sided structure (1,2) superimposed, intermittently connected together so as to form pockets, and in which: * one of the layers exhibits heat shrinkage; * the connection between the layers is carried out by intermittent bonding of a selection of threads to form said pockets.  2 / complex material according to claim 1, characterized in that the layer having a shrinkage under the effect of heat consists, in whole or in part, of son having a shrinkage under said heat effect.  3 / complex material according to claim 1, characterized in that the layer intended to form the inner face consists entirely or partly of son or para-aramid or PBO fibers.  4 / complex material according to claim 1, characterized in that the pockets constitute longitudinal channels, the first layer being produced by an interlacing of the warp (Cl) and weft (Tl) threads, while the second layer is produced by the interlacing of the warp (C2) and weft (T2) threads, so that: the warp (CI) and weft (Tl) threads intended to form the external face during use, are threads selected from the family of meta-aramids exhibiting reduced shrinkage at high temperature; the warp (C2) and weft (T2) threads intended to constitute the reverse side and the insulating layer in the final structure are, for their part, threads selected from the para-aramid family, exhibiting practically no shrinkage under the effect of intense heat; <Desc / Clms Page number 13>  '' the connection between the upper face constituting the outer layer during use and the lining constituting the insulating layer, is carried out by intermittent bonding of a selection of warp threads (CI) with a weft (T2) of the ply forming the thermal barrier.  5 / complex material according to claim 1, characterized in that the pockets constitute diamonds.  6 / complex material according to claim 1, characterized in that the texture ratio between the two layers is between one for one and one for ten.