EP1441613B1 - Heat insulating textile complex - Google Patents

Abstract

The textile laminate for providing thermal insulation is remarkable in that at least one of the walls (P1), and in particular the wall that is to be subjected first to heat, is suitable for shrinking under the effect of heat so as to cause link yarns (F) to stand up, thereby leading to an increase in the spacing between said walls (P1 and P2) that are made in full or in part to be thermostable.

Description

The invention relates to the technical sector of textile articles that can be used as thermal insulators, particularly for the production of protective textile complexes to the risks associated with fire.

The invention is advantageously an application of the textile complex for the manufacture of intervention and protective clothing for firefighters. Of course, 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.

• un tissu externe (A) ;
• une membrane imper-respirante, généralement associée à un substrat (B) ;
• une barrière thermique constituée généralement par un feutre aiguilleté (C) ;
• une doublure de finition (D).

Generally, as schematically shown in FIG. 1, for making intervention and protection jackets, multilayer structures are used in a known manner and consist of four elements, namely:

• an outer fabric (A);
• a waterproof-breathable membrane, generally associated with a substrate (B);
• a thermal barrier generally consisting of needle felt (C);
• a finishing lining (D).

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 number of criteria, including protection against radiant heat and convective heat, have good thermal stability of the constituent materials, meet the criteria of pure flame retardance and possess good impermeability.

It also appeared excessively important to be able to guard against 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 can result in loss of physical capacity, loss of lucidity, fainting or cardiac arrest.

It also appeared important to be able to protect the operator, under extreme and accidental conditions, including by giving him a time of flight. There are indeed situations in which can appear a very rapid transition stage of the development of a fire generating a very rapid increase in seconds, the temperature of 500 to 600 ° C for example which corresponds to a flow of incident heat of the order of 40 kW per m2. It is therefore important to resist this sudden increase in temperature for a sufficient time to move away from home.

In an attempt to achieve these objectives, textile complexes incorporating a thermal insulation consisting of a knitted fabric have been proposed. three-dimensional, as is clear from the teaching of patent EP 0.443.991, or by a felt likely to trap air, as is clear from the teaching of patent EP 0.364.370. Thermal insulation, resulting from trapped air, provides important protection against heat flow. However, in this embodiment of the thermal insulation (three-dimensional meshes or felts), the touch and the appearance are not satisfactory. The garment is often considered unhygienic, uncomfortable to wear and unattractive hence the need to associate the textile complex made, a clean lining. This solution however tends to weigh down the complex while complicating its manufacture.

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

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

In the international application WO00 / 66823, it has been proposed to have the beads of textile material on the surface of a liner. These beads create air channels between a non-flammable textile web and the liner. The presence of these beads increases the abrasion sensitivity of the layer of the complex which carries the beads.

Solutions have also been proposed using spaced parallel layers subjected to means able to vary the space between said layers to create, in a corresponding manner, a thermal barrier. For example, the teaching of patent GB 2,264,705 discloses a textile article composed of two parallel layers consisting of a plurality of son. Each of the layers cooperates with means to be actuated manually to move them relative to each other, which causes the tilting or straightening of the connecting son corresponding to a coming together of said layers, in the inclined position of the son, and at a spacing of the layers in the straightened position of said wires. This solution requires manual intervention and is aimed exclusively at an application for protection against the cold.

In the international application WO99 / 05926, the complex comprises two completely independent layers arranged in two parallel planes in order to define 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 implementation means and generates a structure lacking flexibility.

From this state of the art and to overcome the aforementioned disadvantages, the problem to be solved by the invention is to create a thermal barrier to obtain a moderate insulation in normal situation corresponding to a small thickness for a larger comfort of use and automatically obtain stronger and localized insulation in places where the heat is stronger in an emergency situation.

To solve such a problem, it has been designed and developed a textile complex for thermal insulation, in particular for the production of protective clothing having a woven or knitted structure having at least two walls connected in a spaced manner by a plurality of threads. which has a natural tendency to lie down, so that in this position the spacing is reduced and less than the length of the connecting threads. 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 in order 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 bonding yarns are woven or knitted partially with each of the layers.

In one embodiment, each wall or layer results from an interlacing of warp and weft son son, the connecting son are arranged in a chain, the coating of said son is effected in the weft direction.

Given these provisions, it appears that the fact of using, for at least one layer, a heat-shrinkable material in the weft of the outer face provides an interesting reaction to heat. Indeed, when the temperature reached by the heat-shrinkable layer or wall is sufficiently high, a shrinkage of the weft occurs, which has the effect of straightening the bonding wires and, concomitantly, increasing , as the temperature rises, the thickness of the complex and consequently its insulating capacity.
Furthermore, the selection of a para-aramid connection wire makes it possible, on the one hand, to obtain good resilience and, on the other hand, a sufficient compressive strength when the thermal barrier has been partially carbonized. , 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 trademark "KERMEL ", in pure form or in admixture with other fibers.

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

The complex, as defined, can be combined with an outer ply of flame retardant material and a breathable membrane with substrate.

• la figure 1 est une vue schématique illustrant, comme indiqué, un complexe multicouches du type de ceux parfaitement connus et utilisés à ce jour pour la réalisation de vêtements de personnel d'intervention dans des conditions de risque, notamment de vêtements de sapeurs-pompiers ;
• la figure 2 est une vue en perspective d'une forme de réalisation du complexe textile selon l'invention ;
• la figure 3 est une vue en perspective à caractère purement schématique montrant le complexe textile soumis à une température considérée comme normale ; dans cette position, les fils de liaison sont couchés ;
• la figure 4 est une vue correspondant à la figure 3 montrant, sous l'effet d'une chaleur importante, la rétraction d'une des parois provoquant le redressement des fils de liaison et l'augmentation de l'épaisseur du complexe ;
• 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 described below in more detail with reference to the figures of the accompanying drawings, in which:

• Figure 1 is a schematic view illustrating, as indicated, a multilayer complex of the type of those well known and used to date for the production of emergency personnel clothing under hazardous conditions, including clothing firefighters;
• Figure 2 is a perspective view of an embodiment of the textile complex according to the invention;
• Figure 3 is a purely schematic perspective view showing the textile complex subjected to a temperature considered normal; in this position, the connecting threads are lying down;
• Figure 4 is a view corresponding to Figure 3 showing, under the effect of a significant heat, the retraction of one of the walls causing the straightening of the connecting son and increasing the thickness of the complex;
• Fig. 5 is a graph showing the response of the complex during the rise in temperature in the case of radiant heat;
• Figure 6 is a graph showing the response of the complex during the rise in temperature in the case of convective heat.

The principle of the textile complex according to the invention is illustrated in FIGS. 3 and 4 of the drawings. The complex has a woven or knitted structure having two walls or layers (P1) and (P2) spaced apart by a plurality of threads (F). The bonding yarns (F) are partially woven or knitted with each of the layers.

However, it has been found that the connecting threads (F) have a natural tendency to lie on their side, so that the thickness (e) of the complex considered between the two layers (P1) and (P2) is less important than the length of the connecting wires. It follows therefore 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 (P1) intended to be subjected to a large heat, is able to retract under the effect of said heat. As a result, when the temperature reached by the layer (P1) is sufficiently high, of the order of 200 to 300 ° C for example, there can be, as shown schematically in Figure 4, a retraction of said layer, this will have the effect of straightening the connecting son (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 (P1) and (P2) results from an interlacing of warp and weft son. The connecting son, (F) are arranged in a chain, so that the coating of the latter takes place in the direction of the frame. The realization of this type of complex by weaving or knitting son is well known to a person skilled in the art.

As will be indicated in the remainder of the description, the bonding yarns (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, good resilience. on the other hand, sufficient compressive strength when the thermal barrier is partially charred.

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

The warp and weft threads of each wall (P1) and (P2) are advantageously selected from those of the family of meta-aramids in pure or in a mixture, of the type known under the trademark " KERMEL " (RHODIA) or " NOMEX " (DUPONT) or "CONEX" (TEIJIN). In the example of Figure 2, the wall (P1) is made of warp son (C1) and weft son (T1), heat-shrinkable material. Advantageously, only (T1) is heat-shrinkable. The wall (P2) is made of warp threads (C2) and weft threads (T2). The connecting son (F) are advantageously constituted by a warp connecting the weft son (T1) and (T2) of each of the walls (P1) and (P2).

Each wall (P1) and (P2) may have, by weaving or knitting, the same yarn density. Or, for each wall, this density may be different.
For example, the densest weaving or knitting constitutes the wall intended to be directed towards the user, advantageously acting as a lining.

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

As indicated, the length of the spacing wire between the walls (P1) 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 is recalled that the spacer wire is advantageously a para-aramid-based yarn such as paraphenylene terephthalamide for example (" KEVLAR " from DUPONT, "TWARON" and " TECHNORA " from TEIJIN)

The textile complex as defined according to the features of the invention may be used alone or in combination with other plies son or fibers to form a multilayer article of the type known to those skilled in the art (Figure 1).

For example, the complex as defined is combined with a web consisting of a flame retardant textile and a sheet consisting of a membrane. The membrane is preferably between the flame retardant textile and the thermal insulation textile complex, according to the invention. The flame retardant textile is intended to form a face or wall that will not be in contact with the user. For example, the fireproofed textile is preferably made of a fabric based on isophthalamide metaphenylene fibers or yarns or polyamide-imide, optionally with paraphenylene terephthalamide fibers or yarns, and / or antistatic yarns or fibers or other para-aramid or PBO or PBI fibers or yarns.

The membrane may be constituted by a microporous or hydrophilic film, for example based on polytetrafluoroethylene, flame-retarded polyurethane or polyester. This membrane may be free in the complex or associated for example by gluing to a textile support, such as a fabric or a nonwoven based on meta-aramid fibers or polyamide-imide.

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

The complex according to the invention in combination with a flame retardant textile and a membrane, finds a particularly advantageous application for the manufacture of a garment for protection against the risks associated with fire, for example a firefighter's jacket.

• les fils de chaîne (C1) de la paroi (P1) sont constitués par des filés de fibres de polyamide-imide de titre Nm 80/2 de densité 13 fils/cm ;
• les fils de trame (T1) de la paroi (P1) sont constitués par des filés de fibres de polyamide-imide de titre Nm 60/1 de densité 27 duites/cm ;
• les fils de chaîne (C2) et de trame (T2) de la paroi (P2) sont constitués par des filés de fibres de polyamide-imide de titre Nm 80/2 de densité respective 20 et 27 fils/cm ;
• les fils de chaîne d'espacement (F) sont constitués par des filés de fibres de para-aramide de titre Nm 80/2 de densité 6 fils/cm ;

An embodiment of a textile complex according to the invention is described below, the walls (P1) and (P2) belonging to the armor illustrated in FIG. 2.

• the warp threads (C1) of the wall (P1) consist of polyamide-imide fiber yarns of Nm 80/2 density of 13 yarn / cm density;
• the weft threads (T1) of the wall (P1) consist of polyamide-imide fiber yarns of Nm 60/1 density 27 density / cm;
• the warp (C2) and weft (T2) of the wall (P2) consist of polyamide-imide fiber yarns of Nm 80/2 respective density 20 and 27 son / cm;
• the spacing warp threads (F) are constituted by spun yarns of para-aramid fibers of the title Nm 80/2 with a density of 6 threads / cm;

The mass per unit area of the article is about 240 g / m2 and the spacing between the walls (P1) and (P2) about 2 mm in the normal position (recumbency).

• Selon la norme EN 366, test à la chaleur radiante : 28 secondes en t₂ et 7,3 secondes en t₂-t₁. On renvoie au diagramme de la figure 5.
• Selon la norme EN 367, test à la chaleur convective (figure 6) :
  • HTI 24 (temps théorique de brûlure) de 18 secondes
  • HTI 24 - HTI 12 (temps théorique de douleur) de 5 secondes

Measurements of the thermal flux protection of the complex gave the following results:

• According to EN 366, radiant heat test: 28 seconds in t ₂ and 7.3 seconds in t ₂ -t ₁ . We refer to the diagram of Figure 5.
• According to 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

The result of these graphs, in a remarkable way, is that the typical values "leakage time", that is to say the differences between the times Theoretical burn rates (t2 or HTI 24), and the theoretical pain times (t1 or HTI 12), are greater than the overall mean 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 (t1) and (t2) signifying a theoretical increase in protection after the pain threshold.

The advantages are apparent from the description, in particular it is emphasized that the resulting complex has excellent breathability, excellent visual appearance and excellent thermal protection.

Claims (9)

1. A textile laminate for thermal insulation, in particular for making protective garments, the laminate presenting a woven or knitted structure having at least two walls (P1 and P2) linked together in spaced-apart manner by a plurality of yarns (F) which tend naturally to lie down, such that when in this position, the spacing between the walls is small and less than the length of the link yarns, the laminate being characterised in that at least one of the walls (P1), and in particular the wall that is to be the first that is subjected to heat, is suitable for shrinking under the effect of the heat so as to cause the link yarns (F) to stand up simultaneously, thereby increasing the spacing between said walls (P1 and P2), which walls are made in full or in part to be thermostable.
2. A textile laminate according to claim 1, characterised in that the link yarns (F) are woven or knitted in part with each of the layers or walls (P1 and P2).
3. A textile laminate according to claim 1, characterised in that the link yarns (F) are based on para-aramid.
4. A textile laminate according to claim 1, characterised in that each wall (P1 and P2) is the result of interlacing warp yarns and weft yarns, the link yarns being disposed in the warp direction, said yarns lying down in the weft direction.
5. A textile laminate according to claim 1, characterised in that the warp yarns and the weft yarns of each of the walls (P1 and P2) are selected from those constituting meta-aramid family, on their own or in a mixture.
6. A textile laminate according to claim 1, characterised in that each wall (P1 and P2) presents the same yarn density.
7. A textile laminate according to claim 1, characterised in that the two walls (P1 and P2) present different yarn densities.
8. A textile laminate according to claim 1, characterised in that it is combined with an outer sheet of fireproofed material and a waterproof and breathing membrane with a substrate.
9. The use of a laminate according to any one of claims 1 to 8 for making a protective garment, in particular for a firefighter.

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