EP2155944B1 - Basalt based knitted textile structure - Google Patents

Description

FIELD OF THE INVENTION

The invention relates to a knitted textile structure using basalt fibers. It also relates to the applications of such a structure especially in the context of the realization of non-fire barriers also called firebreak.

The invention also relates to this structure in its application as thermal insulation, electrical insulation and composite reinforcement.

PRIOR STATE OF THE TECHNIQUE

It is well known to use fiberglass as reinforcement fibers of textile structures. These have the advantage of giving the structure thus obtained good mechanical properties but has limits of resistance to chemical attack.

A highly elastic glass fiber structure is known from the document US 5,065,601 .

In the context of textile structures more particularly intended to be subjected to a high temperature, it is known to use basalt, whose inertia in a chemical medium is well known, and whose resistance to high temperatures is implemented in a number of applications. On the other hand, the basalt fibers obtained with the technologies available to date have the disadvantage of being very brittle, so that their integration into textile structures is only done by weaving, or by juxtaposition of fibers. that is to say, is performed only for fiber runs with a very high radius of curvature in limitingly rectilinear introduction. In doing so, the integration of such basalt fibers in the textile structures does not provide the possibility of extensibility or controlled deformation, necessary for certain applications.

SUMMARY OF THE INVENTION

The invention therefore relates to a textile structure composed of a knit, itself made from basalt fibers, said knit being obtained by Jet or Chain knit technology type Rachel.

Among the known textile structures the document DE202004007601 discloses a multiaxial scrim comprising a plurality of layers of threads placed one over the other. This canvas offers good conformability and drapeability, has a great homogeneity and has a smooth surface. The scrim includes unidirectional yarns that can be made of basalt fiber.

On the other hand the document WO2004 / 094137 A discloses a fabric forming a substrate reinforcing in their points of weakness coated fabrics or laminated. The reinforcing fabric may be composed of, among other things, a knit made from basalt fibers obtained by throwing knit technology. The realization of this knit does not specify, however, whether particular precautions are taken to avoid a break in basalt fiber yarns.

In doing so, because of the particular technology used, namely the jetted mesh technology, basalt fibers can be integrated into a knit fabric despite the high radius of curvature of said fibers, below which there is a risk of breaking of said fiber.

Thus, the invention is directed to a method for producing such a textile structure. This method comprises a step of knitting basalt fiber yarns using chaine or Rachel type knitted mesh technology, in which the basalt fiber yarns are fed in a positive manner and virtually -buffer at the knitting organs.

Thanks to the implementation of this technology, it becomes possible to obtain an extensibility of the textile structure of a value of between 10 to 80%, that is to say very much higher than textile structures obtained by weaving or by juxtaposition of fibers. According to the invention, this extensibility can be obtained both in the production direction and in the cross direction, or possibly in both directions. Extensibility is defined here as the ratio of additional length obtained by traction without breaking with respect to the initial length. In the case of a biextensible, this measurement is exerted by pulling in two perpendicular directions simultaneously, always remaining in the proportion of the breaking forces of each of the directions.

According to the invention, the knit forms a grid obtained by partial frames in Jet or Chain type mesh technology.

According to the invention, the knitted textile structure can be locked in production direction or in cross direction by inserting a basalt wire in one or the other direction, depending on the desired blocking direction.

According to the invention, the textile structure thus knitted can also incorporate binding yarns, typically made of polyester, polyaramides or Nomex® (para-aramid) in the case of open mesh grid with partial wefts, in order to hold the structure mechanically.

The blocking of the textile structure can also be obtained in both directions, that is to say, production direction and cross direction by the implementation of the knit technology to knit stitches with front insertion of weft and without embossing.

The invention also relates to the complex structure associating the textile structure of the invention with a layer of a woven material, knitted or nonwoven or film, depending on the desired use of the structure thus obtained and in particular in the framework of cold insulation or fire.

BRIEF DESCRIPTION OF THE DRAWINGS

• La figure 1 est une représentation schématique d'une structure tissée traditionnelle, dans laquelle on retrouve des fils de chaîne et des fils de trame disposés de manière perpendiculaire les uns par rapport aux autres.
• La figure 2 illustre la représentation d'une maille dans laquelle on a montré le rayon de courbure R que l'on fait prendre aux fils dans les diverses réalisations proposées.
• La figure 3 est une représentation schématique d'un tricot réalisé selon la technologie mailles jetées selon l'invention.
• Les figures 4 et 5 sont des variantes de la figure 3, illustrant les extensibilités de ladite structure, respectivement selon le sens travers et selon le sens production.
• La figure 6 est une représentation de la figure 3 avec blocage des mailles en sens travers.
• La figure 7 est une représentation de la figure 3 avec blocage des mailles en sens production.
• La figure 8 est une représentation de la figure 3 avec blocage de la structure sens production et sens travers.
• Les figures 9 et 10 sont des illustrations, respectivement en vue de dessus et en section de l'association des structures précédentes avec un non tissé.

The manner in which the invention can be realized and the advantages which result therefrom will emerge more clearly from the following exemplary embodiment given by way of non-limiting indication in support of the appended figures.

• The figure 1 is a schematic representation of a traditional woven structure, in which we find warp son and weft son arranged perpendicular to each other.
• The figure 2 illustrates the representation of a mesh in which it has been shown the radius of curvature R that is made to the son in the various proposed embodiments.
• The figure 3 is a schematic representation of a knit made according to the technology knitted stitches according to the invention.
• The Figures 4 and 5 are variants of the figure 3 , illustrating the extensibilities of said structure, respectively in the cross direction and in the production direction.
• The figure 6 is a representation of the figure 3 with mesh locking in the cross direction.
• The figure 7 is a representation of the figure 3 with mesh locking in production direction.
• The figure 8 is a representation of the figure 3 with structure blocking meaning production and cross direction.
• The Figures 9 and 10 are illustrations, respectively in plan view and in section of the association of the preceding structures with a nonwoven.

DETAILED DESCRIPTION OF THE INVENTION

The figure 1 is a view of the prior art already described with the limitations already mentioned in terms of extensibility. The warp and weft threads are made of basalt, using a conventional loom. As a result, the extensibility of the structure is reduced to that of the son that constitute it, and is therefore almost zero.

On the other hand, we represented on the figure 3 a knit stitch knit according to the present invention. The threads that constitute it, are entirely in basalt. This structure is obtained with a trade Chain or Rachel, as marketed by the company Karl Mayer.

In order to take into account the large radius of curvature R of the basalt yarns, the traditional installations, and in particular the Rachel loom, are modified by making it possible to bring said basalt yarns in a positive and almost overflow manner to the knitting members. , in order to leave some latitude to the formation of the loops of stitches. In such conditions, the basalt yarns do not undergo excessive tension and therefore do not risk being broken or deteriorated during the various movements to which they are subjected on the knitting members.

Under these conditions, the so-called "slaughtering phase" is particularly controlled when the needle goes down to form precisely the loop of the mesh. By controlling the stroke of said needles, it is possible for the son loops to keep their natural radius of curvature minimum, without creating harmful extension that could be at the origin of breakage son.

In doing so, it becomes possible to carry out the described structure in relation to the figure 3 .

The particular advantage of such a discarded mesh structure lies in the various possibilities of extension of the resulting structure, especially in the transverse direction ( figure 4 ) or in the sense of production ( figure 5 ). Indeed, it leads to an extensibility of up to 60%.

The structure thus described can also be obtained by means of a hook type COMEZ or MULLER.

That said, and according to a feature of the invention, it is possible to block this extension in the cross direction ( figure 4 ), in the sense of production ( figure 5 ) and this, by insertion of a basalt wire respectively cross-direction and production direction. In such a configuration, the textile structure remains extensible in the other direction, respectively in production sense and cross direction.

These rectilinear insertions in warp or weft are preferably made from a creel avoiding intermediate manipulations and by means of bar tubes properly flared for the chains, thus avoiding deterioration of fibers

According to another characteristic of the invention, it is also possible to block the knitted structure in the two main directions, namely cross-direction and weft direction ( figure 6 ). This leads to such a structure by frontal insertion of bidirectional frame on a Rachel loom. The inserted wires, respectively in the cross direction and in the production direction can be basalt, or another material (glass, polyester, aramid, Nomex®) depending on the purpose of the application of said structure.

This structure is then completely blocked, and may in particular have an extensibility of less than or equal to 2% in both directions.

It allows the production of so-called "closed" textiles, thus serving as screens and insulation barriers, or filters that are precise with respect to certain specific applications, in this case, more particularly subjected to corrosive chemical actions or to the temperature. The dimension of the orifices that it defines is determined according to the gauge of the knitting machine, the density of the warp and weft threads, as well as the nature of the threads used.

In doing so, said structure can be used as a filter medium, in particular for the filtration of highly corrosive or chemically very active substances.

It can also find application in the context of the realization of electrical insulation, or thermal insulation, both heat and cold.

But it can also act as reinforcement of composite materials, such as for the constitution of silicone molds that will be used at high temperatures.

In the same spirit, this structure can also be implemented for the realization of pipe lining, including sewers where the material must withstand very aggressive chemical attacks.

It can be associated with this structure binding son, themselves made of basalt, or polyester, aramid, para-aramid, well known under the trade name Nomex®, or the polyaramid.

In doing so, it defines a gate with a predetermined opening, the opening of which can be adjustable, typically from 2 mm to 6 cm on the side, which can then serve as an electrical insulator for example.

The knitted structure 1, 2 thus obtained may also be associated with a layer of woven material, knitted or a nonwoven 4, or even a film. The additional structure thus associated is inserted in the Rachel type machine previously described in the form of a continuous support. It is associated with the nonwoven 4 by means of a binding thread 3.

In doing so, one can thus realize structures for geotextile applications, but also for other applications, and in particular fire barriers by implementing, in connection with the Figures 9 and 10 , a non-woven non-fire quality (polyester, non-fire polyester, glass or basalt). In this hypothesis, it is observed that the bonding wire mesh both around the knitted structure and nonwoven reported.

In the light of this, it is conceivable that the interest of the invention makes it possible, in a simple and economical manner, to produce a knitted structure employing basalt and in particular making it possible to optimally use the characteristics, in particular chemical and physical, of said basalt.

Claims (8)

1. Method of production of a basalt based knitted textile structure comprising a basalt fibre based yarn knitting stage using a warp-knit or warp-stitch type technology, characterized in that the said basalt fibre-based yarns are fed positively, almost at overspeed, into the knitting devices.
2. Textile structure consisting of a knit, itself obtained from a basalt fibre base according to the method of claim 1, characterized in that it offers an extension capability included between 10 and 80 %.
3. Textile structure consisting of a knit, itself obtained from a basalt fibre base according to the method of claim 1, characterized in that the knitting forms a mesh obtained from partial wefts of the warp-knit or warp-stitch type knitting technology.
4. Textile structure consisting of knitting, itself obtained from a basalt fibre base according to the method of claim 1, characterized in that it is locked in the weft or production direction by the insertion of a basalt yarn in one direction or the other, depending on the desired locking direction.
5. Textile structure consisting of knitting, itself obtained from a basalt fibre base according to the method of claim 1, characterized in that it is locked in both directions, respectively in the weft direction and the production direction, by the insertion of a basalt yarn in both directions, through the implementing of a warping technology with frontal insertion of the weft and without shrinkage
6. Textile structure according to claim 5, characterized in that it has an extension capacity at least equal to 2%.
7. Textile structure consisting of knitting, itself obtained from a basalt fibre base according to the method of claim 1, characterized in that it also includes the binding yarns typically consisting of polyester, poly-aramid or Nomex® (para-aramid).
8. Complex textile structure consisting of the combining of a textile structure according to one of the claims 2 to 7 with a layer of woven, knitted or non-woven material (4) or of a film, with the combination made by means of a binder yarn (3)

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