EP1373617B1 - Reinforced fabric - Google Patents

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

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

In the field of personal protective equipment (PPE), different types of textiles are implemented to meet the requirements of the standards in force and thus ensure the necessary and sufficient protection for each of the wearers of clothing.

For example, fireproof textiles for firefighters are found for which thermal performance (resistance to radiant and convective heat, thermal stability, flammability test, etc.) is measured, as well as mechanical performance. antistatic, water-repellent ... There are also other types of fire-resistant textiles for heat-exposed industrial workers where the performance requirements relate mainly to resistance to limited flame spread and resistance to convective heat and radiant. Similarly, there is protective clothing used for welding operations that must have characteristics of non-flammability, primed tear resistance and resistance to small projections of molten metals.
The examples presented above show that there is very often a combination of several characteristics for a textile to conform. Generally associated with mechanical performance (tensile and tear strength) and thermal performance, or mechanical and chemical performance, or mechanical and antistatic.

Personal protective equipment textiles currently on the market use different types of raw materials ranging from flame-retardant treated cottons to aramids and other latest-generation fibers or filaments. The choice of the raw material determines the type of protection of the finished textile, its level of performance, its maintenance method, its price level and its lifetime.

Indeed, the more the choice is for a high-end material having high performance, the more the fabric offers good protection and greater durability, but with a high price. On the other hand, a textile made of a lower-grade flame retardant material has lower performance and longevity, but will be at a more attractive price point. The goal is always to obtain the fabric with the best performance and the best comfort for a good price, one thus seeks to have textiles at the same time powerful, resistant, light and comfortable.

One of the means for improving the lacerations of a fabric is to use a weave known as RIP STOP, which consists of regularly doubling a warp and weft a thread, so as to block the propagation of the tear. Such armor makes it possible to increase by 30% the values of initiated rips. The disadvantage of using such armor is the fact of obtaining a fabric with a certain relief on the front face which causes premature wear of these lined yarns and therefore less abrasion resistance than in the case of a smoother weave like a canvas or a twill.

For this reason, it is inadvisable to use this type of armor on a fabric intended to be printed (camouflage type of the army) since the solidities to dry and wet rubbing would be degraded because of this relief where the abrasion is casting.

In addition, a RIP STOP armor always gives a more pronounced appearance that can be harmful to use, unlike armor smoother as sergeants.

One of the ways to increase the mechanical strength of a fabric is to use a "core wire" technology wire or equivalent where the mechanically strongest raw material is placed in the core of the wire and is covered by one or more other less mechanically resistant raw materials but which provide the coloristic, antistatic properties of the final thread as well as the effective protection of this core with respect to UV, abrasion and aggressions related to the maintenance of clothing.

The disadvantages of these spinning techniques are the following: it is often an expensive technology and limited in fineness of wire which leads to a less important textile clos. It's the case for example the Kermel ^® HTA ^® spun core, where the Technora ^® (high performance para aramid mechanics) is placed in the core to provide the strength of the yarn and where the 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, fabrics made with this type of yarn use a medium fineness yarn - Nm 45/2 - compared to fabrics made of Nomex Delta TA ^® (intimate blend of meta and para aramid) made with a finer yarn - nm 55/2 - which allow to obtain, equivalent weight of fabric, more effective heat shield, since the surface of the Nomex Delta TA ^® is more closed. In contrast, a fabric made from a yarn technology intimate mixture as Nomex Delta TA ^® (75% meta-aramid, 23% para-aramid, 2% antistatic) has lower mechanical performance as core spun mentioned above.

Another way to improve the mechanical performance of a textile is to insert a wire with high mechanical performance regularly in one and / or the other direction of the textile, without changing the construction of the textile. Thus, more mechanically strong fabrics are obtained since the new wire inserted often contains a high percentage of para-aramid; however, this thread may have the disadvantage of bleaching with use and with successive washings, giving a surface appearance of the aged, non-uniform and whitish textile.

To obtain a textile having antistatic properties, it is known to use a conductive or antistatic material intimately mixed with the other materials constituting the textile; this mixture may be uniform in low proportion throughout the textile or more regularly concentrated on some son of 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 scratch effect which may be a disadvantage especially in the case of colors. clear. Only a core wire technology with an antistatic core and a cover in another material allows for a uniform textile in colors; the disadvantage, as stated above, is the high cost of such a wire.

From US 2180770A is known a reinforced fabric comprising on its rear face a reinforcing grid made of warp son and weft son, made of a material having higher mechanical properties than those making the son of the front face.

The object of the invention is to propose a textile for which we have improved, combined and added certain performances, with a view to to optimize its aptitude for a technical use and this, without aesthetically changing one of its faces, while maintaining its textile properties.

For this purpose, the thermal protection fabric that it concerns, comprising, on its front face, armor of warp threads in a direction and weft threads in the perpendicular direction or mesh-type armor, is characterized in that it comprises, on its rear face, a reinforcing grid made up 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 reinforcing grid being linked to the front face by its warp and weft son, the warp and weft threads being fixed on the front face at different points and crossing to the outside of the bottom fabric forming the front face .

The reinforcing threads belonging to the reinforcing grid are punctually bonded to the front face, and intersect by creating super-thicknesses that trap a layer of air participating in better thermal insulation of the fabric. This is particularly important when the fabric is used for making a garment for firefighters, the various materials used being then made of non-fire and non-fuse materials.

Advantageously, the reinforcing grid is bonded to the base fabric during the manufacture thereof.

According to one embodiment of this fabric the reinforcing grid is formed by a cross-type of canvas reinforcement son arranged in warp and weft.

Advantageously, the different threads in the two directions are combined so as to form a complex weave of the 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 cross threads, for example twill, give a surface appearance similar in every way to a standard twill fabric (weight and identical construction) that would not have this grid. Thus, the characteristics of the appearance of the outer surface will be retained.

This construction makes it possible to obtain a good resistance to abrasion of the outer face, an excellent preservation of the appearance after washing, a better printability due to the good fastness to friction compared to a rip stop armor.

The reinforcing son may, for example, be made of a material having mechanical performance superior to that of the material of the ground wire. An interesting construction aims to bind the reinforcing son in the bottom twill regularly, so as to provide a considerable improvement in breaking strengths and initiated tears, the dimensional stability of the fabric, and also to increase its resistance to breakage open (opening the fabric after prolonged exposure to a flame) or flash caused by an electric arc. This type of construction therefore makes it possible to produce fabrics that are much more resistant to identical weights. It is also possible to build textiles of lighter weight and therefore more comfortable for mechanical characteristics equivalent to a structure without reinforcement grid.

In addition, since the reinforcing threads are not bound in the bottom, they form small warp and weft floats that intersect perpendicularly creating over-thickness at each cross, these over-thicknesses participating in the thermal insulation of the tissue. Indeed, this grid effect makes it possible to increase the thickness of the fabric, a thickness all the more important that 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 in this grid on the back of the sensitive materials 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 outer face of the fabric.

The reinforcing grid also makes it possible to provide additional performance to the fabric such as antistaticity or conductivity. The advantage of placing conductive wires in the rear face makes it possible to maintain a uniform surface appearance in color while providing electrical properties.

Other materials can be inserted voluntarily reinforcing grid as fibers or carbon filaments (very sensitive to abrasion), micro-encapsulated products, materials with shape changes, grafted yarns ...

• en chaîne : 6 fils de fond et 1 fil de renfort, soit un fil tous les 2 millimètres
• en trame : 5 fils de fond et 1 fil de renfort, soit un fil tous les 2 millimètres

According to one embodiment of this fabric, the armor of the face is made of 2/1 twill for a fabric weight of 225g / m2. The ground wires bind on the front face and the reinforcing wires on the back face. The proportions between the ground threads and the reinforcing threads are as follows:

• in chain: 6 threads and 1 reinforcing thread, one thread every 2 millimeters
• in weft: 5 threads and 1 reinforcing thread, one thread every 2 millimeters

• les fils de fond sont réalisés en mélange intime de méta et para aramide avec un faible pourcentage de polyamide carbone tels que connus sous la marque Nomex Comfort^®, le titre utilisé est du Nm 60/2.
• les fils de renfort sont réalisés en para aramide craqué, tel que connus sous la marque Kevlar^® ou Technora^®, le titre utilisé est du Nm 50/2.

Next one possibility:

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

The reinforcing son form on the rear face floats of about 2 millimeters which intersect perpendicularly forming a small raised point directed towards the rear of the fabric. This increase in thickness of the fabric makes it possible to obtain improved thermal results compared to a closed fabric of identical weight without a grid.

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

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

By this construction, in the case of adding antistatic properties to the textile, it will be possible to obtain a smooth and homogeneous front face in composition and colors 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 cloth seen from the inside that is to say the side of the reinforcing grid;

Figure 2 is a cross-sectional view, perpendicular to the weft son, along the line II-II of Figure 1.

The drawing shows a fabric having warp armor in a direction and a weave of weft yarns 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 reinforcing grid composed of warp threads 4 and weft threads 5. As is clear from the figures 1 and 2, the warp yarns and the weft yarns are bonded on the front face of the fabric at different points and intersect at points 6 outside the bottom fabric forming the front face. It is apparent from Figure 2 that in some locations, there are 4 layers of son superposed, forming a multitude of small points that define a network maintaining an air layer promoting 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 as an example, it encompasses all variants remaining within the scope of the claims. It is thus particularly that the front face of the fabric could comprise a mesh type armor, without departing from the scope of the invention.

Claims (9)

1. A 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, comprising on its back face, a reinforcing grid composed of warp threads (4) and of weft threads (5) produced from a material possessing higher mechanical properties than those producing the threads of the front face, characterised in that the reinforcing grid is connected to the front face by means of its warp and weft threads, the warp threads (4) and weft threads (5) being fastened to the front face at different points and intersecting on the outside of the ground fabric forming the front face.
2. The fabric as claimed in claim 1, characterized in that the reinforcing grid is connected to the ground fabric during the manufacture of the latter.
3. The fabric as claimed in one of claims 1 and 2, characterized in that the reinforcing grid is formed by a linen-type interlacing of the reinforcing threads (4, 5) arranged in warp and in weft.
4. The fabric as claimed in one of claims 1 to 3, characterized in that the various threads (2, 3, 4, 5) in the two directions are combined as to form a complex weave of the linen, twill or satin type, such that the front or outer face of the fabric is composed essentially of the ground threads and the inner face of the reinforcing threads.
5. The fabric as claimed in one of claims 1 to 4, characterized in that the component threads (4, 5) of the reinforcing grid are of high tenacity, such as aramid.
6. The fabric as claimed in claim 5, characterized in that the component threads (4, 5) of the reinforcing grid are produced from cracked para-aramid, such as is known under the trademark Kevlar® Technora®.
7. The fabric as claimed in one of claims 1 to 6, characterized in that the component threads (2, 3) of the front face of the fabric are produced by an intimate mixture of meta and para-aramid with a small percentage of carbon polyamide, known under the trademark Nomex Comfort®.
8. The fabric as claimed in claims 6 and 7 taken as a whole, characterized in that the weave of the front face is produced in 2/1 twill for a fabric weight of 225 g/m², the proportions between the ground threads (2, 3) and the reinforcing threads (4, 5) being as follows :

   - in warp : 6 ground threads and 1 reinforcing thread, that is to say 1 thread every 2 mm,

   - in weft : 5 ground threads and 1 reinforcing thread, that is to say 1 thread every 2 mm,

   the count of the ground threads being Nm 60/2 and the count of the reinforcing threads being Nm 50/2.
9. The fabric as claimed in any one of claims 1 to 4, characterized in that the reinforcing grid contains other elements selected from carbon fibers or filaments, microencapsulated products, form change materials, grafted threads, etc.

Images