WO2002079555A2

WO2002079555A2 - Reinforced fabric

Info

Publication number: WO2002079555A2
Application number: PCT/FR2002/001100
Authority: WO
Inventors: Frédérique FAVIER; Jean-Pol Kahn
Original assignee: Europrotect France Sa
Priority date: 2001-03-29
Filing date: 2002-03-28
Publication date: 2002-10-10
Also published as: DK1373617T3; JP2004530800A; BR0208369A; BR0208369B1; CA2441591A1; WO2002079555A3; NZ528349A; ES2274027T3; DE60216062T2; FR2822855A1; FR2822855B1; ATE345411T1; EP1373617B1; EP1373617A2; PT1373617E; CA2441591C; DE60216062D1

Abstract

The invention concerns a reinforced fabric comprising on its front surface a warp yarn weave (2) in one direction and a weft yarn weave (3) in the perpendicular direction or a mesh-type weave. Furthermore, said fabric comprises on its rear surface a reinforcing grid consisting of warp yarns (4) and weft yarns (5) produced in a material having different properties, such as higher mechanical properties than those producing the yarns of the front surface, the reinforcing grid being linked to the front surface by its warp and weft yarns, the warp yarns (4) and the weft yarns (5) being fixed on the front surface in different points and intersecting outside the ground fabric forming the front surface.

Description

REINFORCED FABRIC

The present invention relates to a reinforced fabric. It can in particular be a fabric used in an individual protective clothing, especially a thermal protective fabric for the production of clothing used by firefighters, or even a fabric used in the case of risky environments, for mechanical, chemical protection against an electric arc, in the case of an explosive atmosphere ...

In the field of Personal Protective Equipment (PPE), different types of textiles are used to meet the requirements of the standards in force and thus provide the necessary and sufficient protection for each wearer of clothing.

By way of example, there are thus flame retardant textiles for firefighters for which thermal performance (resistance to radiant and convective heat, thermal stability, flammability test, etc.) are measured, but also mechanical performance, anti-static, water-repellent ... There are also other types of fire-resistant textiles for workers in the industry exposed to heat where the performance requirements relate mainly to resistance to limited flame spread and resistance to convective heat and radiant. Similarly, there are protective clothing used for welding operations which must have characteristics of non-flammability, resistance to initiated tearing and resistance to small splashes of molten metal. The examples presented above show that there is very often a combination of several characteristics for a textile to conform. Mechanical performance (tensile strength and tear resistance) and thermal performance are generally associated, or mechanical and chemical performance, or mechanical and antistatic performance.

Textiles for personal protective equipment currently on the market use different types of raw materials ranging from treated flame retardant cottons to aramids and other latest generation flame retardant fibers or filaments. The choice of raw material determines the type of protection of the finished textile, its performance level, its maintenance method, its price level and its lifespan. Indeed, the more the choice is made towards a high-end material having high performance, the more the fabric offers good protection and greater durability, but at a high price. Conversely, a textile made from a lower-end flame retardant material has lower performance and longevity in use but will be at a more attractive price level. The goal is always to obtain the fabric with the best performance and the best comfort for an attractive price, so we seek to have textiles that are efficient, resistant, light and comfortable. One of the means for improving the initiated tears of a fabric is to use a weave known under the name RIP STOP, which consists in regularly doubling in warp and weft a thread, so as to block the propagation of the tear. Such armor increases the values of tears initiated by 30%. The disadvantage of using such a weave is the fact of obtaining a fabric with a certain relief on the front face which results in premature wear of these doubled threads and therefore less good abrasion resistance than in the case of a smoother weave like a canvas or twill.

For this reason, it is not recommended to use this type of weave on a fabric intended to be printed (army camouflage type) since the solidities with dry and wet friction would be degraded because of this relief where abrasion is casting.

In addition, a RIP STOP weave always gives a more marked appearance which can be harmful to use, unlike smoother weaves such as twill.

One of the means of increasing the mechanical resistance of a fabric is to use a technology wire “core wire” or equivalent where the most mechanically resistant raw material is placed in the core of the wire and is covered by one or more other raw materials less mechanically resistant but which provide the coloristic and antistatic properties of the final thread as well as the effective protection of this core against UV rays, abrasion and attacks linked to the maintenance of clothing.

The disadvantages of these spinning techniques are as follows: it is very often an expensive technology and limited in the fineness of the yarn, which results in a less significant closure of the textile. It's the case for example Kermel ^® HTA ^® core spun, where Technora ^® (high mechanical performance para aramid) is placed in the core to provide the resistance of the wire and where Kermel ^® (polyamide imide) is placed on the cover to give the final color of the product as well as the protection of the soul. Thus, the fabrics produced with this type of thread use a thread of average fineness - title Nm 45/2 - compared to the fabrics realized in Nomex Delta TA ^® (intimate mixture of meta and para aramid) constructed with a thread of greater fineness - Nm 55/2 - which make it possible to obtain, at equivalent fabric weight, a more efficient heat shield since the surface of the Nomex Delta TA ^® fabric is more closed. On the other hand, a fabric made from an intimate blend technology yarn such as Nomex Delta TA ^® (75% meta aramid, 23% para aramid, 2% antistatic) has lower mechanical performance than the previously mentioned core spun. Another way to improve the mechanical performance of a textile is to insert a high mechanical performance thread regularly in one and / or the other direction of the textile, without modifying the construction of the textile. This results in more mechanically resistant fabrics since the new thread inserted often contains a high percentage of para aramid; however, this yarn can have the disadvantage of whitening in use and with successive washings, giving a surface appearance of the aged textile, non-uniform and whitish.

To obtain a textile having antistatic properties, it is known to use a conductive or antistatic material in intimate mixture with the other constituent materials of the textile; this mixture can be uniform in small proportions throughout the textile or much more regularly concentrated on certain yarns in both directions. In both cases, depending on the antistatic material used, it appears more or less on the surface of the textile giving a mottled appearance or a more or less marked grid or stripe effect which can be a disadvantage especially in the case of colors. clear. Only a core yarn technology with an antistatic core and a cover in another material makes it possible to make a uniform textile in colors; the drawback, as stated above, is the high cost of such a wire. The object of the invention is to provide a textile for which we have improved, combined and added certain performances, with a view to optimize its suitability for technical use, without aesthetically changing one of its faces, while retaining its textile properties.

To this end, the thermal protection fabric which it relates to, comprising, on its front face, a weave of warp threads in one direction and of weft threads in the perpendicular direction or a weave of mesh type, is characterized in that '' it comprises, on its rear face, a reinforcement grid composed of warp and weft threads made of a material having different properties, such as higher mechanical properties than those producing the threads of the front face, the reinforcement grid being linked to the front face by its warp and weft threads, the warp and weft threads being fixed on the front face at different points and crossing on the outside of the background fabric forming the front face . The reinforcing wires belonging to the reinforcing grid, are punctually linked to the front face, and intersect by creating extra thicknesses which trap a layer of air participating in better thermal insulation of the fabric. This is particularly important when the fabric is used for the production of a garment for firefighters, the various materials used then being made of non-fire and non-fusible materials.

Advantageously, the reinforcing grid is linked to the base fabric during the manufacture of the latter.

According to one embodiment of this fabric, the reinforcing grid is formed by a web-like interlacing of the reinforcing threads arranged in warp and weft.

Advantageously, the different threads in the two directions are combined so as to form a complex weave of canvas, twill or satin type, such that the front or outer face of the fabric is composed essentially of the bottom threads and the inner face of the reinforcing threads.

These crossing bottom threads, for example in twill, give a surface appearance similar in every way to a standard twill fabric (of identical weight and construction) which would not have this grid. Thus, the characteristics of the appearance of the external surface will be preserved. This construction makes it possible to obtain a good abrasion resistance of the external face, an excellent conservation of the appearance after washing, a better aptitude for printing due to the good resistance to friction compared to a rip stop weave. The reinforcing wires can, for example, be made of a material having mechanical performance superior to that of the material of the bottom wire. An interesting construction aims to tie the reinforcing threads in the background twill regularly, so as to bring a considerable improvement in terms of breaking strengths and initiated tears, dimensional stability of the fabric, and also to increase its resistance to breakage. open (opening of the fabric following prolonged exposure to a flame) or to the flash caused by an electric arc. This type of construction therefore makes it possible to produce much more resistant fabrics with identical weights. It is moreover possible to build textiles of lighter weight and therefore more comfortable for mechanical characteristics equivalent to a structure without reinforcement grid.

In addition, as the reinforcing threads are not linked at the bottom, they form small floats of warp and weft which intersect perpendicularly creating extra thicknesses at each crossing, these extra thicknesses participating in the thermal insulation of the tissue. Indeed, this grid effect makes it possible to increase the thickness of the fabric, thickness all the more important as the floats of the reinforcing threads cross perpendicularly on the rear face forming a multitude of small crosses or small points which constantly maintain a layer of air in this network.

Thanks to this type of construction, one can also choose to incorporate into this grid on the rear face of materials sensitive to external elements (UV radiation, abrasion ...). It is thus possible to use, to obtain a textile with improved mechanical properties, all types of aramid (and especially para-aramids) in the constituents of the reinforcing thread since the fibrillation of this thread will be maintained on one of the faces of the textile, without polluting the other side which is the outside of the fabric. The reinforcement grid also provides additional performance to the fabric such as antistaticity or conductivity. The advantage of placing conductive wires on the rear face makes it possible to maintain a uniform surface appearance in color while providing electrical properties.

Other materials can be inserted voluntarily in a reinforcement grid such as carbon fibers or filaments (very sensitive to abrasion), micro-encapsulated products, materials with change of shape, grafted wires ...

According to an embodiment of this fabric, the weave of the face side is made of 2/1 twill for a fabric weight of 225 g / m2. The bottom wires link on the front face and the reinforcement wires on the rear face. The proportions between the bottom wires and the reinforcement wires are as follows:

- in chain: 6 bottom wires and 1 reinforcement wire, i.e. one wire every 2 millimeters

- in weft: 5 bottom wires and 1 reinforcement wire, i.e. one wire every 2 millimeters

According to one possibility:

- the bottom wires are made from an intimate mixture of meta and para aramid with a small percentage of carbon polyamide as known under the brand Nomex Comfort ^® , the title used is Nm 60/2. - reinforcing the son are made of para aramid cracked, as known under the trademark Kevlar ^® or Technora ^®, the title used is Nm 50/2.

The reinforcing threads form floats on the rear side of approximately 2 millimeters which intersect perpendicularly forming a small point in relief directed towards the rear of the fabric. This gain in thickness of the fabric makes it possible to obtain improved thermal results compared to a closed fabric of identical weight without grid.

This reinforcement grid also makes it possible to significantly increase the resistance to rupture and tearing of the fabric. The values obtained were compared with those of a 100% Nomex Delta C ^® fabric of identical weight and construction but without reinforcement grid, and a gain of at least 40% was measured for the breaking strengths and at least 150% for initiated tears.

In addition, this article has been tested up to 25 tumbler washing and drying cycles to verify the preservation of the appearance; the result is extremely satisfactory since no fibrillation and no whitish appearance of the surface were observed.

By this construction, in the case of adding antistatic properties to the textile, it will be possible to obtain a smooth front face which is homogeneous in composition and color since the antistatic grid of the rear face will be effective but invisible.

The invention is described below with reference to the attached schematic drawing showing an embodiment of this fabric.

Figure 1 is a view of a piece of fabric seen from the inside, that is to say from the side of the reinforcement grid;

Figure 2 is a cross-sectional view thereof, perpendicular to the weft threads, along line 11-11 of Figure 1.

The drawing represents a fabric comprising a weave of warp threads in one direction and a weave of weft threads in the perpendicular direction. The warp threads are designated by the reference 2 and the weft threads by the reference 3. This fabric comprises on its rear face a reinforcement grid composed of warp threads 4 and weft threads 5. As is clear from the figures 1 and 2, the warp threads and the weft threads are linked on the front face of the fabric at different points and intersect at points 6 outside the background fabric forming the front face. It is apparent in particular from FIG. 2 that in certain locations, there are 4 thicknesses of superimposed wires, forming a multitude of small spikes which delimit a network maintaining a layer of air promoting the thermal insulation provided by the fabric. It goes without saying that the invention is not limited to the sole embodiment of this fabric, described above by way of example, on the contrary it embraces all the variants remaining within the scope of the claims. Thus, in particular, the front face of the fabric could include a mesh type weave, without going beyond the ambit of the invention.

Claims

1. Reinforced fabric of the type comprising, on its front face, a weave of warp threads (2) in one direction and of weft threads (3) in the perpendicular direction or a weave of the mesh type, characterized in that it comprises, on its rear face, a reinforcement grid composed of warp threads (4) and weft threads (5) made of a material having different properties, such as higher mechanical properties than those producing the threads of the front face, the reinforcement grid being linked to the front face by its warp and weft threads, the warp (4) and weft (5) threads being fixed on the front face at different points and crossing outside the background fabric forming the front face.

2. Fabric according to claim 1, characterized in that the reinforcing grid is linked to the background fabric during the manufacture thereof.

3. Fabric according to one of claims 1 and 2, characterized in that the reinforcing grid is formed by a web type interlacing of the reinforcing threads (4, 5) arranged in warp and weft. 4. Fabric according to one of claims 1 to 3, characterized in that the different threads (2, 3,

4, 5) in the two directions are combined so as to form a complex weave of canvas, twill or satin type, such that the front or outside face of the fabric is composed essentially of the bottom threads and the inside face of the reinforcing threads. 5. Fabric according to one of claims 1 to 4, characterized in that the constituent son (4,

5) of the reinforcement grid are of high tenacity such as aramid.

6. Fabric according to claim 5, characterized in that the son (4, 5) constituting the reinforcing grid are made of cracked para aramid, as known under the brand Kevlar ^® Technora ^® .

7. Fabric according to one of claims 1 to 6, characterized in that the son (2, 3) constituting the front face of the fabric are made by an intimate mixture of meta and para-aramid with a low percentage of carbon polyamide , known under the brand Nomex Comfort ^® .

8. Fabric according to all of claims 6 and 7, characterized in that the weave of the front face is made of 2/1 twill for a weight of 225 g / m ² fabric, the proportions between the bottom threads (2, 3) and the reinforcing threads (4, 5) being as follows:

- in warp: 6 bottom threads and 1 reinforcing thread, or one thread every 2 mm, - in weft: 5 bottom threads and 1 reinforcing thread, or one thread every

2 mm, the title of the bottom wires being Nm 60/2 and the title of the reinforcement wires being Nm 50/2

9. Fabric according to any one of claims 1 to 4, characterized in that the reinforcing grid contains other elements chosen from carbon fibers or filaments, microencapsulated products, materials with change of shape, grafted wires