EP2204482A1 - Heating textile structure - Google Patents

Abstract

The structure has resistive threads (303) for releasing heat by Joule effect. The resistive threads are connected in warp, weft or selvedge by conductive warp threads (304) of low resistance. The conductive threads are integrated in a fabric weave during fabrication. Filling threads are made of polyester, cotton or polyamide/silver and integrated in the structure for ensuring mechanical resistance and non fire character.

Description

FIELD OF THE INVENTION

The invention relates to a knitted fabric structure for releasing heat during use of the product. The products can be used in various fields such as clothing (professional clothing, sports ...), furniture (car seats, curtains ...), medical equipment (orthoses, lumbar belts ...) , packaging, geotextiles (road antifreeze, road or airstrip, heating in the ground ...).

It can also be technical uses such as heating or temperature maintenance equipment for various pipes or fluid lines, the protection of mechanical and electronic elements against low temperatures (de-icing aircraft), the heating of coating solutions or glue ...

This list is not exhaustive; the application of the invention is also envisaged in all the fields where diffusion / convection of heat is sought by exposing the object or by wrapping a part of a living or inert body.

PRIOR STATE OF THE TECHNIQUE

It has already been made of more or less flexible materials, more or less modelable on a shape, to provide thermal protection or ability to heat by providing a heat source Joule effect.

These materials are generally made by integrating, in a heterogeneous structure, often multilayer, electrical resistances in the form of resistive son traversing the structure. More recently, other textiles have been coated with a conductive substance.

• concentrer l'émission de chaleur autour des résistances,
• rendre l'assemblage plus rigide,
• presque toujours perdre l'élasticité que l'on peut obtenir par un textile.

This solution has the following drawbacks:

• to concentrate the emission of heat around the resistances,
• make the assembly more rigid,
• almost always lose the elasticity that can be achieved by a textile.

The heat is not uniformly distributed throughout the textile surface and the temperature rises as you are close to the wire. It is then often necessary to use a second layer of textile avoiding contact between the hot spot and the body to be heated. The conductive wire is often composed of more rigid metal elements, which decreases the flexibility of the textile. The addition of metal son to a textile significantly decreases the flexibility and expandability of the latter.

• soit ils sont connectés en un point ce qui n'assure pas une répartition uniforme de l'intensité électrique et cela provoque l'apparition de zones plus chaudes que d'autres, présentant même parfois des risques de points chauds (brûlure, incendie). On montre clairement par thermographie que l'émission de chaleur n'est pas homogène.
• soit ils sont connectés par des éléments mécaniques ou filaires de faible résistance, rapportés sur la structure, et qui répartissent l'intensité électrique (tresse, plaque).

The problem of the connection also arises for these fabrics which must be connected to a source of energy (transformer, battery or other):

• or they are connected at one point which does not ensure a uniform distribution of the electric intensity and this causes the appearance of warmer areas than others, sometimes even having the risk of hot spots (burning, fire). It is clearly shown by thermography that the heat emission is not homogeneous.
• or they are connected by mechanical or wire elements of low resistance, reported on the structure, and which distribute the electrical intensity (braid, plate).

In all cases, this brings rigidity to the final product (loss of flexibility in the connections), an increase in volume (thickness due to the folds of the fabric on itself and seams). These solutions also require additional implementation work that increases the cost significantly.

SUMMARY OF THE INVENTION

The invention provides a novel solution for homogenizing the heat and maintaining the flexibility and elasticity of the textile support.

The invention relates to a textile structure made by knitting technology discarded mesh chain or Rachel. The structure is composed of several types of yarns or fibers used simultaneously, some of which may be insulating and others resistant. The textile therefore has a heating resistance by Joule effect.

The invention lies in the insertion of the connector wire in the same frame of the textile.
More specifically, the structure of the invention comprises resistive heating son, ensuring heat release Joule effect, connected together, in a warp, weft or edge by one or more conductor wires of significantly lower resistance, integrated in the weave itself of the knit at the time of manufacture and without significant loss of flexibility of the textile.

In other words, a wire of a different and very significantly more conductive nature is introduced into the very armor of the knit and provides the connection to the energy source. The distribution of the electrical intensity of the current is then very homogeneous thanks to a very good contact between the connection son and the resistive son. Resistive wires form in effect of the loops around the conductive son, completely enclosing the wire and ensuring a contact of perfect quality, much higher than what could be obtained by weaving, for example.

These son conduct uniformly distribute the electrical intensity in all resistive son; it follows that the heating is very homogeneous over the entire surface of the textile.

Indeed, the heating textile can be likened to a network of resistances as presented on the figure 1 .

The desired resistances R make the textile heating Joule effect. The resistors kR correspond to the linear resistances of the wires or connection systems. These resistances can disturb the homogeneity of heat diffusion. On the other hand, they must be minimized in order to limit unnecessary losses.

The power generated by each band, that is to say by each resistive wire and by the connection wires, can be calculated by the basic electrical laws. It will be demonstrated on a three-band model, but it can be generalized to a larger number of bands or to a continuous textile.

The calculations on this resistor network show that the value of the resistance kR must not exceed 1/100 ^th of the resistance R, without which the three bands represented on the figure 1 no longer heat at equivalent power, and hot spots are created on the power connections.

This modeling demonstrates the interest of having a highly conductive wire distributing the electrical intensity in the textile The demonstration can be carried to any number of heating strips, or even to a resistant textile, and therefore heated over its entire surface.

The conductive yarns are introduced in full or partial weft in knit stitch technology (Chain or Rachel) or in weaving. They can also be warp knit technology in various weaves.

These conductors son are introduced with a spacing corresponding to the size of the article to achieve through electronic programming or with a submultiple lower step exact or approximate to the size of the article to achieve.

This eliminates the additional operation to integrate the connectors. In addition the conductive wires do not appear on the surface, reducing any extra thickness
or risks of attachment, since they are inserted in the same armor of the knitting.

Moreover, it has been found that the resistive textile threads are not always homogeneous when their strength makes it difficult to reproduce the articles. Measurements of resistance are observed along said wires which can be up to 3 to 20 times the mean value. The capacity of the yarn manufacturing processes to obtain a homogeneous resistivity is sometimes mediocre

These resistance peaks can induce localized overheating points or the cancellation of electrical current in the branch if other resistive wires are in parallel.

As shown in figure 2 it is then possible to short-circuit the resistance peak by placing highly conductive wires, which act as equipotential straight lines. A resistor network is then made with more points connecting the resistors, which allows a better distribution of the electrical intensity and therefore of the thermal power.

• d'homogénéiser la dissipation de chaleur,
• de faciliter la connexion à la source d'énergie sans surépaisseur, sans perte de souplesse, et sans risque d'accrochage ;
• de réduire les risques de points de surchauffe localisés, susceptibles de générer des risques de brûlures et d'incendie ;
• d'éviter le surcoût inhérent aux étapes supplémentaires de confection,
• de permettre l'utilisation des fils résistifs moins performants (variation de résistance) par création d'équipotentielles intermédiaires.

In conclusion, the insertion into the textile structure of the connection wires (connecting the heating resistive wires to the energy source) thus makes it possible:

• to homogenize the heat dissipation,
• to facilitate the connection to the energy source without extra thickness, without loss of flexibility, and without risk of snagging;
• to reduce the risk of localized overheating points, which could lead to burns and fire;
• to avoid the extra cost inherent in the additional manufacturing steps,
• to allow the use of less efficient resistive son (variation of resistance) by creating intermediate equipotentials.

DESCRIPTION OF THE DRAWINGS

The manner in which the invention can be realized and the advantages which result therefrom will emerge more clearly from the following exemplary embodiments, given as an indication and not a limitation to the accompanying figures.

• La figure 1 déjà décrite représente schématiquement le principe de résistances électriques mis en oeuvre par l'invention.
• La figure 2 également déjà décrite illustre schématiquement le moyen de court-circuiter les points chauds, susceptibles de se développer dans une structure textile chauffante.
• Les figures 3 et 4 illustrent schématiquement deux méthodes connues de réalisation de surface souple chauffante.
• La figure 5A est une représentation schématique d'une structure tricotée simple de type chaînette tramée, conformément à l'invention, dont la figure 5B est une illustration schématique en détail.
• Les figures 6A et 6B représentent schématiquement d'autres variantes de la structure textile de l'invention.
• La figure 6C tend à illustrer la mise en oeuvre de bandes chauffantes au sein de la structure textile de l'invention.
• La figure 7 représente schématiquement un tricot double fonture.

It is clarified that the thickness of the lines of the figures is not representative of that of the son used. Their distinction (thickness, dotted lines ...) simply allows a better differentiation of the threads for the understanding of the graphs. In addition, the dots are not to be confused with any armor (left / caught or under). Beyond the types of armor described, the invention is applicable with many armor chosen according to the desired properties.

• The figure 1 already described schematically represents the principle of electrical resistances implemented by the invention.
• The figure 2 Also already described schematically illustrates the means of short-circuiting the hot spots, likely to develop in a heating textile structure.
• The figures 3 and 4 schematically illustrate two known methods of producing a flexible heating surface.
• The Figure 5A is a schematic representation of a simple knitted structure of the halftone chain type, according to the invention, whose Figure 5B is a schematic illustration in detail.
• The Figures 6A and 6B schematically represent other variants of the textile structure of the invention.
• The Figure 6C tends to illustrate the implementation of heating strips within the textile structure of the invention.
• The figure 7 schematically represents a double needle-shaped needle.

DETAILED DESCRIPTION OF THE INVENTION

The invention consists in integrating highly conductive son in a heating textile armature, composed of heating resistive son (a certain electrical resistance) and possibly also electrically insulating son. The insertion of the conductive threads in the same fabric armor allows an optimized distribution of heat distribution by very uniform distribution of the electrical intensity that circulates in the different parts of the textile. The textile connections of the armor allow both an electrical contact of very good quality and the conservation of the characteristics of the flexible material.

The examples given below are not limiting but are intended to better identify the possibilities offered by this new technique.

1. 1. les fils conducteurs appelés aussi « fils de connexion », qui sont les fils reliant la source d'énergie aux fils résistifs chauffants. Ces fils sont en général réalisés en métal conducteur de type cuivre, argent ou tout autre métal ou alliage très conducteur, par exemple le Monel®. Ce sont des fils métalliques mono ou multifilaments ou des fils guipés dont l'un des constituants est métallique (par exemple : un guipage d'argent sur une âme en caoutchouc pour des propriétés à la fois élastiques et conductrices).
2. 2. les fils chauffants, qui sont des fils de résistivité suffisamment importante pour produire une élévation de température sensible par effet Joule. Ces fils peuvent être par exemple réalisés en polymère (polyamide, polyester...) intégrant, recouvert ou enduit par un procédé quelconque (guipage, enduction ou tout autre procédé) d'une partie de l'ordre du µm d'épaisseur, de métal conducteur (argent, inox, cuivre...). Ces fils peuvent être aussi des fils issus d'un mélange particulier (par exemple d'acier et d'inox).
3. 3. Enfin éventuellement, les fils de liage ou « remplissage », sont des fils qui peuvent être hétérogènes. On choisit soit des fils pour leur faible coût (polyester ou autre), soit des fils pour leur touché (coton, soie), ou encore pour leurs propriétés mécaniques (aramides), ou encore pour leur propriétés fongicides et anti-bactériennes. On peut également utiliser des fils électriquement peu conducteurs et thermiquement conducteurs afin de permettre un meilleur transfert de chaleur (par exemple des fils Polyamide Argent). On peut, de manière générale, mettre en oeuvre tout autre fil ayant des caractéristiques fonctionnelles particulières pour assurer une autre fonction typiquement une résistance mécanique ou un caractère non feu.
   Le choix de ces fils de liage ou remplissage dépend des autres fonctionnalités (hors fonction chauffage) recherchées pour l'application finale. Le choix reste libre, la seule condition imposée est qu'ils soient faiblement conducteur électrique sinon ils doivent être analysé en fils résistifs dans le système.

As already indicated, the textile structure of the invention comprises two or three types of son:

1. 1. Conductive wires also called "connection wires", which are the wires connecting the energy source to the resistive heating wires. These wires are generally made of conductive metal of the copper, silver or other highly conductive metal or alloy type, for example Monel®. These are single or multifilament metal son or gimped son of which one of the constituents is metallic (for example: a silver wrapping on a rubber core for both elastic and conductive properties).
2. 2. Heating wires, which are resistivity wires of sufficient magnitude to produce a Joule-sensitive temperature rise. These yarns may for example be made of polymer (polyamide, polyester, etc.) incorporating, covered or coated by any process (covering, coating or any other process) with a portion of the order of one micron thickness, conductive metal (silver, stainless steel, copper ...). These son can also be son from a particular mixture (eg steel and stainless steel).
3. 3. Finally, finally, the son of binding or "filling", are son that can be heterogeneous. We choose either son for their low cost (polyester or other), or son for their touch (cotton, silk), or for their mechanical properties (aramids), or for their fungicidal and anti-bacterial properties. It is also possible to use electrically insulating and thermally conductive wires in order to allow better heat transfer (for example Silver Polyamide wires). In general, it is possible to use any other wire having particular functional characteristics to ensure another function, typically a mechanical strength or a non-fire character.
   The choice of these son of binding or filling depends on the other functionalities (excluding heating function) sought for the final application. The choice remains free, the only condition imposed is that they are weakly electrical conductor otherwise they must be analyzed in resistive son in the system.

The various structures described below are therefore characterized by the fact that the three types of son form an integral part of the reinforcement of the textile surface. Neither the conductive wires nor the resistive heating wires are added to the surface of the textile; they do not need to be fixed in any way (heat-setting, sewing, folding, gluing or other). This avoids any loss of flexibility of the textile. In addition, it avoids additional cost and manufacturing time.

The textile structure of the invention can also be obtained on different types of textile machines. The weave can be very simple as very complex, such as a jacquard fabric or even a double fabric needle for example pocket type in order to use the drawing function or pocket for heating the material.

The wires are imperatively integrated in the armor. Their resistance is mainly between 0.01 Ohm and 100 Ohms per linear meter. The resistance of these wires is approximately 10 to 10,000 times lower than that of the heating resistive wires so as to ensure a very good distribution of the electrical intensity throughout the textile structure by the heating wires.

The heating resistive son form with possibly the binding son, most of the desired armor. Their resistance is mainly between 50 Ohms and 20,000 Ohms per linear meter.

In addition, the heating resistive son are also likely to be coated with a conductive polymer film (for example by coating processes, extrusion or even sol-gel type), to perfect the regularity of heating, these methods providing good homogeneity.

The filling or binding threads provide the complement of the armor to simply play a filling function or provide other functional characteristics. These filler wires may also be selected for their thermal conductivity (eg silver polyamide) to promote optimized heat diffusion throughout the fabric.

The insertion of the conductive son in contact with the heating son, depending on the type of armor used, allows in all cases to promote good contact between these two types of son, which reduces the contact resistance, reduces the risk of points hot, and promotes the homogeneity of the heating. This quality of contact ensures the uniformity of distribution of the intensity in the resistive heating wires, which being parallel, of length and therefore of equivalent resistance, behave like resistors connected in parallel. The resistance of the conductive wires is negligible compared to that of the resistive heating wires.

• un tricot dont le fil de maillage est un fil résistif chauffant. Le fil de chaînette est un fil de remplissage remplacé en lisière de pièce ou avec un pas sous-multiple de la pièce à réaliser par un fil très conducteur ;
• une chaînette tramée faite d'un fil de liage (avec des propriétés spécifiques éventuelles) reliant le fil de connexion (inséré en chaînette), au fil résistif chauffant (inséré dans le sens chaîne), ou inversement ;
• une chaînette tramée où le fil de liage est le fil résistif chauffant et où un fil de remplissage non conducteur est inséré en trame alternativement avec un fil conducteur à une certaine fréquence.

According to the invention, the heating textile structure is obtained by using the Rachel type jet mesh technology or crochet loom. In this technology, the possibilities are important. Indeed, among all the possibilities of weave mesh discarded, we can cite the following examples:

• a knit whose mesh yarn is a heating resistive yarn. Chain yarn is a filling thread replaced at the piece edge or with a sub-multiple step of the part to be made by a highly conductive thread;
• a halftone chain made of a binding yarn (with any specific properties) connecting the connection wire (inserted in a chain), the heating resistive wire (inserted in the chain direction), or vice versa;
• a halftone string where the binding yarn is the heating resistive wire and wherein a non-conductive filler wire is inserted alternatively with a conducting wire at a certain frequency.

It can be envisaged that the wire inserted in the frame is a partial frame.

Similarly, it is conceivable to insert one or more layers of textile (woven, knit, nonwoven or film) on which is deposited the son of connectors and heaters, and over which one knits, thus assembling the son of the heating system to an existing flexible material. This type of assembly can be performed on a machine type Rachel with insertion of "fleece", that is to say a continuous surface for example non-woven, woven
or even polymer film. The material obtained thus forms a multilayer providing a number of functionalities, and for example impact resistance (bullet-proof vests or the like), puncture resistance or filtration of a geotextile, watertightness, thermal reverberation or simply simply diffusion of heat.

It is also possible to work in double needle. The interest is then to be able to heat the material, for example a cable or a duct, isolated from the others and with a larger contact area, the textile surrounding the object to be heated.

Another possibility is to insert the son of connectors in the edges of the fabric for example for large heating elements heating blanket type or ground heating zone (landing strip or access path). They are then connected to the heating resistive son and son base, thus allowing the heating of the textile structure, but son of connectors are not present in the center of the textile surface, it is still more flexible.

One can play on the more or less repetitive distribution of heating resistive son and son of connectivity in the armor. At the level of the textile surface, it is also possible to play on the continuous or repeated presence at regular intervals of resistive heating wire strips. This allows, during the manufacture of the textile structure, to orient the textile to a homogeneous heating, pre-positioned strips to define the heating zones.

• un matériau composé de plusieurs couches assemblées par matelassage pour les couvertures chauffantes par exemple, dans lequel est introduit un fil ou un câble résistif.
  La diffusion de chaleur n'est pas homogène sur toute la surface et le matériau perd ses qualités textiles de souplesse et d'éventuelle élasticité.
• un matériau composé de fils résistifs 202 introduits dans l'armure ou recouvert d'une enduction résistive, mais nécessitant un mode de connexion en surface apporté à ce matériau sous forme de fil, de tresse ou barre de connexion 203, (couture, replis, pince...) pour obtenir une répartition de l'intensité électrique.
• une variante peut consister à réaliser une connexion ponctuelle (par exemple avec un bouton pression) si des fils résistifs sont aussi introduits en trame ou dans un tricot, comme présenté en figure 4B, mais on comprend bien alors que l'intensité électrique ne se répartit pas de façon égale et que l'on n'obtiendra pas un résultat thermographique homogène.

Thus, we have described in relation to figures 3 and 4 :

• a material consisting of several layers assembled by quilting for the heating blankets for example, in which is introduced a wire or a resistive cable.
  The heat diffusion is not homogeneous over the entire surface and the material loses its textile qualities of flexibility and possible elasticity.
• a material composed of resistive yarns 202 introduced into the weave or covered with a resistive coating, but requiring a mode of surface connection brought to this material in the form of a wire, braid or connecting bar 203, (seam, folds, clip ...) to obtain a distribution of the electrical intensity.
• a variant may consist in making a point connection (for example with a snap button) if resistive wires are also introduced in weft or in a knit, as shown in FIG. Figure 4B but it is well understood that the electrical intensity is not distributed equally and that we will not obtain a homogeneous thermographic result.

The Figure 5A is a schematic representation of a simple knitted structure of the halftone chain type, in which we find the son in the warp direction 501 and 503 and others in the weft direction 502 and 504. The wire 504 is a very conductive wire type copper , connected to the power supply, which ensures the arrival of the current on the heating resistive son 503, which emit heat by Joule effect. The son 502 are son inserted in weft which can be of various types depending on their function: they serve as a filling (type PES or PP for example), or to bring mechanical properties (aramid type).

The Figure 5B highlights the quality of the contact made between the conductor wire 504 and the heating resistive wire 503 which is meshed and thus clamped against the conductive wire, providing a very good connection and conduction. Indeed, the mesh provides the round wire and is in contact with the latter along the entire circumference of its section.

Of course, other combinations are possible. Indeed, we can consider making the chain with a heating resistive wire for example. The choice of the son is left to the user according to the desired functionalities and the economic optimization of the realization.

The Figure 6A represents a knitted structure that differs from the figure 5 in that the heating resistive wire is not inserted in a chain but is a partial frame. There are therefore the warp 601 and weft 602 son that form the matrix. The high resistivity wire 603 which brings the heating power constitutes a partial frame.

This armor also makes it possible to put the conductive threads in chains at the ends of the structure or in a repetitive step ( fig 6B ). In fact, this arrangement also makes it possible for the conductive wire, which is much less resistant, to have a very good distribution of the intensity in the resistive heating wires, which themselves form a homogeneous network of resistance in the weft direction.

The resistive heating wire 603 can thus form heating strips through the textile ( Figure 6 C) . Finally, the conduction wire 604 connecting the electrical source to the resistors, that is to say to the resistive heating son is inserted in the frame. It can be inserted either at the ends of the textile, or evenly through the structure, facilitating its cutting. It should be noted that the 603 wire pass is only an example and that many other possibilities are to be glimpsed.

The figure 7 represents a double needle bed knitting structure. This creates a volume in the structure, in which one can introduce the material to be heated, such as pipes or pipes. Any type of armor is conceivable if it respects the conditions imposed by a structure double needle. In the example given, the wire 701 corresponds to the connector wire which is placed at the ends, connected by heating resistive son 702 all held in the armor (or held by bonding) by the wire 703.

The invention makes it possible to obtain open and stable mesh structures, such as, for example, open grids, typically 5 × 5 mm or even 10 × 10 mm, offering breathable and breathable capabilities, and this, at reduced manufacturing prices.

Claims (10)

Knitted heating textile structure characterized : ■ in that it is carried out according to the mesh technology discarded type chain or Rachel or technology weaving on hooks; And in that the resistive heating wires, providing Joule effect heat release, are connected together, in a warp, weft or edge fashion by one or more very significantly lower resistance conductor wires integrated into the armor. itself of knitting at the time of manufacture and without significant loss of flexibility of the textile. Knitted heating textile structure according to claim 1, characterized in that the conductive wires are introduced at the ends of said structure. Knitted textile heating structure according to one of claims 1 and 2, characterized in that the conductive son are further introduced into the structure in a repetitive step, evenly or not in a warp or weft. Knitted heating textile structure according to one of the preceding claims, characterized in that the heating resistive wires are brought into contact in the weave of the knitted fabric at the time of manufacture of the knit fabric with conducting yarns also constituting the weave whose resistance linear is significantly lower than that of the heating surface in a proportion at least greater than 10. Knitted heating textile structure according to one of the preceding claims, characterized in that the heating resistive wires are coated with a conductive polymer film. Knitted heating textile structure according to one of the preceding claims, characterized in that it also incorporates filling threads, in particular made of polyester, cotton, polyamide, or any other yarn having particular functional characteristics to ensure another function, typically a mechanical resistance or a non-fire character. Knitted heating textile structure according to Claim 6, characterized in that the filling threads are yarns selected for their good heat conduction. Knitted heating textile structure according to Claim 7, characterized in that the filling threads consist of polyamide / Ag. Knitted textile heating structure according to one of the preceding claims, characterized in that it is associated with Rachel "fleece" technology with a layer of flexible material of woven, knitted, non-woven or film type. Knitted heating textile structure according to one of the preceding claims, characterized in that it is made of double needle bed capable of obtaining 3D textiles, directly giving a heating jacket.

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