FR2831772A1 - TEXTILE COMPLEX FOR THERMAL INSULATION - Google Patents

Abstract

The invention concerns a textile complex for thermal insulation characterized in that one of the walls (P1) at least, in particular the wall designed to be first subjected to heat, is designed to retract under the effect of heat to simultaneously straighten the connecting fibers (F) corresponding to an increase of the spacing between said walls (P1 and P2) designed to be entirely or partly heat-stable.

Description

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TEXTILE COMPLEX FOR THERMAL INSULATION
The invention relates to the technical sector of textile articles which can be used as thermal insulators, in particular for the production of complex textiles for protection against risks linked to fire.

textile pour la confection de vêtements d'intervention et de protection pour exti 1 t les sapeurs-pompiers. Bien évidemment, cette application ne doit pas être considérée comme limitative. The invention advantageously relates to an application of the complex

textile for making intervention and protective clothing for outdoor firefighters. Obviously, this application should not be considered as limiting.

 Thus, the textile complex according to the invention finds application in all cases where one is in the presence of extreme conditions, for example during a fire, and more generally to provide protection against a high heat source.

 Generally, as shown diagrammatically in FIG. 1, in order to produce intervention and protection jackets, multilayer structures are used, in a known manner, which consist of four elements, namely: an external fabric (A); a waterproof-breathable membrane, generally associated with a substrate (B); a thermal barrier generally constituted by a needle felt (C); a finishing lining (D).

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 This state of the art can be illustrated by the teaching of patent FR 1,213. 415.

 It is also known that this type of protective clothing must have a certain number of criteria, in particular protection against radiant heat and against convective heat, have good thermal stability of the constituent materials, fulfill criteria of pure flammability and have good waterproofing.

 It also appeared excessively important to be able to protect oneself from the risk of heat stress which is a physiological phenomenon resulting from an increase in the internal temperature of the body which no longer manages to thermoregulate. This may result in a loss of physical capacity, a loss of lucidity, fainting or else cardiac arrest 11 also appeared important to be able to protect the operator, in extreme and accidental conditions, in particular by providing him with a flight time. There are indeed situations in which a very rapid transition stage of the development of a fire can appear, generating a very rapid increase, in a few seconds, in the temperature from 500 to 600 C for example, which corresponds to a heat flow. incident of the order of 40 kW per m2. It is therefore important to resist this sudden increase in temperature for a time sufficient to move away from the focus.

 In an attempt to achieve these objectives, textile complexes have been proposed incorporating a thermal insulator constituted by a knitted fabric

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 three-dimensional, as is apparent from the teaching of patent EP 0.443. 991, or by a felt capable of trapping air, as is apparent from the teaching of patent EP 0.364. 370. The thermal insulation, resulting from the trapped air, provides significant protection against heat flows. However, in this embodiment of the thermal insulator (three-dimensional mesh or felt), the feel and the appearance are not satisfactory. The garment is often considered as unhygienic, unpleasant to wear and unsightly hence the need to associate with the textile complex produced, a lining of cleanliness. This solution however tends to weigh down the complex while complicating its preparation.

 It has also been observed that three-dimensional meshes or felts tend to limit the evacuation of water vapor resulting from perspiration, which increases the phenomena of thermal stress.

 In an attempt to remedy these drawbacks, it has been proposed to replace the thermal insulators made up of three-dimensional meshes or felts, by other structures capable of trapping air. A solution emerges from the teaching of patent application WO99 / 35926 which reports on a membrane on which spacers are arranged at regular intervals in order to create a layer of air between said membrane and a textile surface forming example lining office. The spacers, formed by polymer pads fixed to said membrane, tend to increase the abrasion sensitivity of the other layers of the complex thus produced.

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 In international application WOOO / 66823, it has been proposed to have beads of textile material on the surface of a lining. These beads create air channels between a non-flammable textile sheet and the lining. The presence of these beads increases the sensitivity to abrasion of the layer of the complex which carries the beads.

 Solutions have also been proposed using spaced parallel layers subject to means capable of varying the space between said layers to create, in a corresponding manner, a thermal barrier. We can cite for example the teaching of patent GB 2,264. 705 which discloses a textile article composed of two parallel layers made up of a plurality of threads. Each of the layers cooperates with means which have to be actuated manually to move them relative to one another, which causes the inclination or straightening of the connecting wires corresponding to a bringing together of said layers, in an inclined position of the wires, and a spacing of the layers in the upright position of said wires. This solution requires manual intervention and is aimed exclusively at an application for protection against the cold.

 In international application WO99 / 05926, the complex comprises two completely independent layers, arranged in two parallel planes in order to delimit a space for the positioning of a shape memory material. Under the effect of heat, the shape memory material varies the space between the two layers. This solution therefore requires special means of implementation and generates a structure lacking flexibility.

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 From this state of the art and to remedy the aforementioned drawbacks, the problem which the invention proposes to solve is to create a thermal barrier making it possible to obtain moderate insulation in normal situation corresponding to a small thickness for a greater comfort of use and automatically obtain stronger and localized insulation in places where the heat is stronger in an emergency.

 To solve such a problem, a textile complex for thermal insulation has been designed and developed, in particular for the production of protective clothing having a woven or knitted structure having at least two walls linked in a spaced manner by a plurality of threads. which naturally tends to lie down, so that in this position the spacing is reduced and less than the length of the connecting wires. At least one of the walls, in particular the wall intended to be subjected to heat, is capable of shrinking under the effect of heat to cause, concomitantly, the straightening of the connecting wires corresponding to an increase spacing between said walls made in whole or in part to be thermostable.

 Advantageously, the connecting threads are partially woven or knitted with each of the layers.

 In one embodiment, each wall or layer results from an interlacing of warp threads and weft threads, the connecting threads are arranged in a warp, the coating of said threads being carried out in the weft direction.

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 In view of these provisions, it appears that the fact of using, for at least one of the layers, a heat-shrinkable material in the weft of the external face makes it possible to obtain an advantageous reaction to heat. In fact, when the temperature reached by the heat-shrinkable layer or wall is sufficiently high, there is a retraction of the weft, which has the effect of straightening the connecting wires and, concomitantly, of increasing as the temperature rises, the thickness of the complex and therefore its insulating capacity.

 Furthermore, the selection of a connection wire made of para-aramid material makes it possible, on the one hand, to obtain good resilience and, on the other hand, sufficient resistance to compression when the thermal barrier has been partially charred. , taking into account the thermostability characteristics of the connecting wire.

 Advantageously, the warp and weft threads of each wall are selected from those of the family of polyamide-imides of the type of those known under the KERMEL brand, in pure form or as a mixture with other fibers.

 Each wall has the same density of wires, or the two walls have different densities of wires.

 The complex, as defined, can be combined with an external sheet of flame-retardant material and a waterproof-breathable membrane with substrate.

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- la figure 5 est un graphique montrant la réponse du complexe pendant la montée en température dans le cas d'une chaleur radiante ; - la figure 6 est un graphique montrant la réponse du complexe pendant la montée en température dans le cas d'une chaleur convective. The invention is set out below in more detail with the aid of the figures of the appended drawings in which: - Figure 1 is a schematic view illustrating, as indicated, a multilayer complex of the type of those perfectly known and used to date for the production of clothing for intervention personnel under risk conditions, in particular clothing for firefighters; - Figure 2 is a perspective view of an embodiment of the textile complex according to the invention; - Figure 3 is a perspective view of a purely schematic nature showing the textile complex subjected to a temperature considered normal; in this position, the connecting wires are lying; - Figure 4 is a view corresponding to Figure 3 showing, under the effect of significant heat, the retraction of one of the walls causing the straightening of the connecting wires and the increase in the thickness of the complex;

- Figure 5 is a graph showing the response of the complex during the temperature rise in the case of radiant heat; - Figure 6 is a graph showing the response of the complex during the temperature rise in the case of convective heat.

 The principle of the textile complex according to the invention is illustrated in Figures 3 and 4 of the drawings. The complex has a woven or knitted structure having two walls or layers (PI) and (P2) linked in a spaced manner by a plurality of threads (F). The connecting threads (F) are partially woven or knitted with each of the layers.

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 However, it has become apparent that the connecting wires (F) have a natural tendency to lie on their sides, so that the thickness (e) of the complex considered between the two layers (PI) and (P2), is less important than the length of the connecting wires. It therefore follows that a straightening of these connecting son, will cause, correspondingly, an increase in space (e).

 To obtain this result, at least one of the walls, in particular the wall (PI) intended to be subjected to significant heat, is capable of shrinking under the effect of said heat. It follows that when the temperature reached by the layer (PI) is sufficiently high, of the order of 200 to 300 C for example, there may be, as shown schematically in Figure 4, a retraction of said layer, this which will have the effect of straightening the connecting wires (F) causing, concomitantly, an increase in thickness (e) as the temperature rises. This obviously results in an increase in the insulating capacity of such a complex.

 From this basic concept, different embodiments can be envisaged.

 For example, each wall or layer (PI) and (P2) results from an interlacing of warp and weft threads. The connecting wires, (F) are arranged in a warp, so that the coating of the latter takes place in the direction of the weft. The production of this type of complex by weaving or knitting yarns is perfectly known to a person skilled in the art.

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 As will be indicated in the following description, the connecting wires (F) are a para-aramid known for its very good thermostability, which makes it possible to obtain, on the one hand, good resilience and, on the other hand On the other hand, sufficient resistance to compression, when the thermal barrier is partially charred.

 It is recalled that at least one of the walls is woven or knitted from yarns comprising thermostable yarns.

 The warp and weft threads of each wall (PI) and (P2) are advantageously selected from those of the family of meta-aramids in pure or mixed form, of the type of those known under the brand KERMEL (RHODIA) or NOMEXF ( DUPONT) or CONEX (TEIJIN). In the example of FIG. 2, the wall (Pl) is made of warp threads (CI) and of weft threads (Tl), of heat-shrinkable material. Advantageously, only (Tl) is thenl1 retractable. The wall (P2) is made of warp threads (C2) and of weft threads (T2). The connecting son (F) are advantageously constituted by a warp wire connecting the weft son (T1) and (T2) of each of the walls (PI) and (P2).

 Each wall (PI) and (P2) can have, by weaving or knitting, the same density of yarn. Or, for each wall, this density can be different.

 For example, the densest weaving or knitting constitutes the wall intended to be directed towards the user, advantageously acting as a lining.

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 The thermostable wires used can be made of artificial or natural synthetic material, or a mixture. Preferably, yarns based on meta-aramid, for example metaphenylene isophthalamide or polyamide-imide, are used, optionally in combination with flame-retardant viscose. It is also possible to use yarns based on a mixture of modacrylic fibers and flame retardant cotton.

( ) > de DUPONT, TWARON et TECHTARA de TEIJIN)
Le complexe textile tel que défini selon les caractéristique de l'invention peut être utilisé seul ou en combinaison avec d'autres nappes de fils ou de fibres pour constituer un article multicouches du type de ceux connus pour un homme du métier (figure 1). As indicated, the length of the spacing wire between the walls (PI) and (P2) determines the space (e) between these walls and therefore the thickness of the air mattress thus formed for thermal insulation. The length of the connecting wire (F) is preferably between 1 and 10 mm approximately. It will be recalled that the spacer wire is advantageously a wire based on para-aramid such as paraphenylene terephthalamide for example

()> from DUPONT, TWARON and TECHTARA from TEIJIN)
The textile complex as defined according to the characteristics of the invention can be used alone or in combination with other plies of yarns or fibers to constitute a multilayer article of the type of those known to a person skilled in the art (FIG. 1).

 For example, the complex as defined is combined with a sheet made of a flame retardant textile and a sheet made of a membrane.

The membrane is preferably between the flame-retardant textile and the textile thermal insulation complex according to the invention. The flame retardant textile is intended to form a face or wall which will not be in contact with the user. For example, the flame retardant textile preferably consists of a fabric based on metaphenylene isophthalamide threads or fibers or

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 polyamide-imide, optionally with threads or fibers of paraphenylene terephthalamide, and / or threads or fibers antistatic or other para-aramid or fibers or threads type PBO or PBI.

. if ignifugé ou de polyester. Cette membrane peut être libre dans le complexe ou associée par exemple par contre collage à un support textile, tel qu'un tissu ou un non-tissé à base de fibres de méta-aramide ou de polyamideimide. The membrane may consist of a microporous or hydrophilic film, for example based on polytetrafluoroethylene, polyurethane

. fireproof or polyester yew. This membrane can be free in the complex or associated, for example, by bonding to a textile support, such as a fabric or a nonwoven based on meta-aramid or polyamideimide fibers.

 This withdrawal effect from one of the layers can also result from the presence of a membrane fixed to the layer in question. For example, this membrane can be made of any material capable of exhibiting shrinkage under the effect of heat such as microporous polyurethane, hydrophilic polyurethane, hydrophilic polyester, etc.

n ignifugé et une membrane, trouve une application particulièrement avantageuse pour la confection d'un vêtement pour la protection contre les risques liés au feu, par exemple une veste de sapeur-pompier. The complex according to the invention in combination with a textile

n flame retardant and a membrane, finds a particularly advantageous application for the manufacture of a garment for protection against risks linked to fire, for example a firefighter jacket.

 An embodiment of a textile complex according to the invention is described below, the walls (PI) and (P2) falling within the armor illustrated in FIG. 2.

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La masse surfacique de l'article est d'environ 240 g/m2 et ZD l'espacement entre les'parois (PI) et (P2), d'environ 2 mm en position normale (liaison couchée). the warp threads (CI) of the wall (PI) consist of yarns of polyamide-imide fibers of Nm 80/2 title with a density of 13 threads / cm; the weft threads (Tl) of the wall (PI) consist of yarns of polyamide-imide fibers of title Nm 60/1 with a density of 27 picks / cm; the warp (C2) and weft (T2) yarns of the wall (P2) consist of yarns of polyamide-imide fibers of Nm 80/2 title with respective density 20 and 27 yarns / cm; the spacing warp yarns (F) consist of yarns of para-aramid fibers of Nm 80/2 title with a density of 6 yarns / cm;

The surface mass of the article is approximately 240 g / m2 and ZD the spacing between the walls (PI) and (P2), approximately 2 mm in the normal position (lying down connection).

Measures of protection against the thermal flows of the complex have given the following results:
According to standard EN 366, radiant heat test: 28 seconds in t2 and 7.3 seconds in t2-tl. We refer to the diagram in Figure 5.

'HTI 24 (temps théorique de brûlure) de 18 secondes * HTI 24-HTI 12 (temps théorique de douleur) de 5 secondes
Il résulte de ces graphiques, d'une manière remarquable, que les valeurs types temps de fuite , c'est-à-dire les différences entre les temps According to standard EN 367, convective heat test (figure 6):

'' HTI 24 (theoretical burn time) of 18 seconds * HTI 24-HTI 12 (theoretical pain time) of 5 seconds
It follows from these graphs, in a remarkable manner, that the standard values of leak times, that is to say the differences between the times

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 theoretical burn (t2 or HTI 24), and theoretical pain times (tl or HTI 12), are higher than the general average observed for complexes of this level. There is also a significant increase in thickness under the effect of radiant heat, and an increase in the difference between (tl) and (t2) signifying a theoretical increase in protection after the pain threshold.

 The advantages emerge clearly from the description, in particular it is emphasized that the complex obtained has excellent breathability, an excellent visual appearance, as well as excellent thermal protection.

Claims (9)

CLAIMS - 1-Textile complex for thermal insulation especially for the production of protective clothing with a woven or knitted structure having  1 1 1 at least two walls (PI) and (P2) linked in a spaced manner by a plurality of threads (F) which naturally tends to lie down, so that, in this position, the spacing is reduced and less than the length of the connecting wires, characterized in that at least one of the walls (Pl), in particular the wall intended to be subjected, first of all, to heat, is capable of shrinking under the effect of heat to cause, concomitantly, the straightening of the connecting wires (F) corresponding to an increase in the spacing between said walls (PI) and (P2) made wholly or in part to be thermostable. - 2-textile complex according to claim 1, characterized in that the connecting son (F) are woven or knitted partially with each of the layers or walls (Pl) and (P2). - 3-textile complex according to claim l, characterized in that the connecting son (F) are based on para-aramid. - 4-textile complex according to claim 1, characterized in that each wall (PI) and (P2) results from an interlacing of warp threads and weft threads, the connecting threads are arranged in warp, the coating of said thread is carried out in the weft direction. <Desc / CRUD Page number 15> - 5-textile complex according to claim 1, characterized in that the warp and weft son of each wall (PI) and (P2) are selected from those of the family of meta-aramides, in pure or in mixture. - 6-textile complex according to claim 1, characterized in that each wall (PI) and (P2) has the same density of son. - 7-textile complex according to claim 1, characterized in that the two walls (PI) and (P2) have different son densities. - 8-textile complex according to claim l, characterized in that it is combined with an outer sheet of flame retardant material and a waterproof-breathable membrane with substrate. - 9- Use of the complex according to any one of claims 1 to 8 for the production of protective clothing, especially for firefighters.