WO2003053530A1

WO2003053530A1 - Reinforcing layer for a composite structure such as a roller or gliding board

Info

Publication number: WO2003053530A1
Application number: PCT/FR2002/004440
Authority: WO
Inventors: Serge Solviche
Original assignee: Salomon S.A.
Priority date: 2001-12-21
Filing date: 2002-12-18
Publication date: 2003-07-03
Also published as: FR2833849B1; FR2833849A1; AU2002364464A1

Abstract

The invention concerns a reinforcing layer for a composite structure such as a roller or gliding board comprising two parallel roving yarn assemblies oriented in different weft and warp directions, part at least of the weft yarns being bulked yarns (12), the warp yarns (10) being non-bulked yarns. The invention is characterized in that the bulked weft yarns (12, 18, 19, 24) are interwoven with the warp yarns (10, 16, 26). The invention also concerns a gliding or roller board having such a reinforcing layer.

Description

Reinforcement sheet of a composite structure such as a rolling or sliding board

The invention relates to a reinforcing ply of a composite structure such as a rolling or sliding board, in particular a ski, a surfboard or a skateboard.

The invention also relates to the rolling or sliding board comprising at least one such reinforcement ply.

A gliding board such as a ski is a composite structure which includes a central core and on top and bottom of the upper and lower reinforcing layers.

These reinforcing layers can be layers of fibers impregnated with resin and / or metallic layers of alloys.

In the case of fiber reinforcement layers, plies of fibers which are pre-impregnated with resin are commonly used, the polymerization of the resin being activated when the ski is baked in the mold.

The sheets of fibers are generally made up of what is called a roving, that is to say fibers, in particular glass fibers, stretched according to continuous and parallel filaments. The fiber layers may be unidirectional, that is to say that all the rovings are oriented in a single direction, or bidirectional, which amounts to two layers of superimposed unidirectional roving oriented in different directions.

As a general rule, the roving is placed on a non-woven veil formed of short fibers deposited randomly. The roving and the veil are assembled by a seam using binding threads.

For such a sheet, the veil improves the holding of the roving by serving as a support and makes the sewing operation easier.

Then, during the impregnation of resin which is produced for example by soaking, the veil absorbs more resin than the roving, it therefore constitutes a reserve of resin which facilitates the bonding of the reinforcing layer on the core or, where appropriate. on a layer of metal reinforcement or alloy, and allows better filling in certain areas of the mold. In addition, the fact that the tablecloth retains more than resin on one side than on the other facilitates the handling operations during the cutting of the sheet and the establishment of the reinforcing layers in the mold.

However, the drawback of this layer is that there is a significant risk of delamination at the interface between the roving and the veil when the ski is highly stressed, for example in bending. Indeed the roving and the veil are retained only by the binding threads and by the resin which coats the whole. This interface is an area of weakness in the superposition of the different layers.

Another drawback of this sheet is that it is complex and not very economical to produce. Indeed, the different layers of the web are first prepared in isolation and then brought to an assembly machine which is, for example, of the Malimo or Libat type and which sews with the binding thread. These assembly machines have capacities limited in width, and commonly the maximum width of the ply is limited to 1270 millimeters.

However, there is a need for larger layers. A wider tablecloth makes it possible to have lower manufacturing costs. In addition, there is more flexibility to adapt the width of the sheet to the capacity of other manufacturing machines, including the resin impregnation machine. There is also more flexibility and therefore less fall to make the cuts of the reinforcements.

Finally, with the existing plies it is difficult to fully control the quality of the veil and the binding thread. The veil in particular can take the resin in an irregular way from where possible irregularities of the bonding or in the additional contributions of resin.

Patent application EP 1072293 proposes improving this type of reinforcing ply by the use of composite voluminized fibers on one of the faces of the ply. Under these conditions, the sheet is formed of two layers of roving son which are superimposed and assembled together by a binding wire, one of the layers being formed by voluminized son. Due to their larger volume, these volumized yarns retain more resin. In these conditions it is also possible to do without the veil. A drawback of this embodiment is that the sheet remains complex despite everything. Indeed, the technique of assembling the sheet remains substantially the same. The layers which form the sheet are assembled by the binding wire. Under these conditions, the dimensions of the sheet remain limited to the capacity of the assembly machine.

In addition, as the layers of the web are simply superimposed, the resistance to interlayer, for example during a peeling test is mainly based on the tensile strength of the binding wire.

An object of the invention is to propose a new reinforcement ply without a veil which is simpler to produce from the point of view of the assembly technique and therefore economical.

Another object of the invention is to provide a reinforcing ply whose resistance to one interlayer is improved.

To this end, the reinforcing ply according to the invention for a composite structure of the gliding or rolling board type comprises two sets of roving son oriented in different directions, the roving son in one of the directions being called weft son. and the yarns of the other direction being called warp yarns, at least part of the weft yarns being volumized yarns, the warp yarns being non-voluminized yarns. It is characterized by the fact that the voluminized weft threads are interlaced with the roving warp threads.

The interweaving of the volumized yarns with the warp yarns results from the production of the web not with a so-called "assembly" machine but with a conventional weaving machine. Such a machine allows the web to be produced in a single operation from rovings. Since the width capacity of a weaving machine is much greater than that of a traditional assembly machine, it is possible to manufacture reinforcing plies in a wider width range.

The volumized threads retain the resin more which makes it possible to do without the veil. Their intertwining with the threads of the other ply makes it possible to dispense with the binding threads and therefore, in the end, there is a resistance to interlayer greater than what a traditional binding wire can produce. The invention will be better understood by referring to the description below and to the attached drawings which are attached to it.

Figure 1 shows a ski in cross section.

Figure 2 is a schematic perspective view of a reinforcing ply produced according to a first embodiment of the invention.

Figure 3 shows the appearance of the reinforcement ply of Figure 2 on one side.

FIG. 4 shows the appearance of the other face of the reinforcement ply of FIG. 2.

Figure 5 relates to an alternative embodiment of the reinforcing ply.

FIG. 6 schematically represents in perspective a variant implementation of the invention.

To illustrate the invention, FIG. 1 shows a cross-section of a ski 1. This ski has a structure of a known type with a central core 2, for example composed of a plurality of wooden strips glued together and machined to shape desired, a gliding sole 4, an upper decor layer 5, and between these different elements of the upper and lower reinforcement assemblies 8 and 9. Each reinforcement assembly comprises one or more reinforcement layers which may be reinforcement layers in glass or other fibers impregnated with resin, or metallic or alloy layers.

In the case of a fiber reinforcement layer, in a known manner, a fiber reinforcement ply is used which is then impregnated with resin. The polymerization of the resin is carried out during the cooking of the ski in the mold.

It goes without saying that the structure of the ski described is not limiting and that the invention applies to any mode of construction of a ski and even more generally of a gliding or rolling board having a laminated structure.

According to the invention, a fiber reinforcement layer comprises two layers of roving son oriented in different directions. At least one of the plies contains volumized yarns, that is to say yarns which have undergone a treatment for example by an air jet texturing technique, by false twist or other to increase their apparent volume. A texturing technique for obtaining such voluminized yarns is for example described in patent application FR 2310431. Other techniques can also be used.

As is known, voluminized yarns have the particularity of absorbing and retaining more resin than conventional yarns. In addition, as they are more hydrophilic than non-volumized yarns, they offer a less tacky feel when handled.

Under these conditions, they advantageously replace the veil.

According to the invention, the reinforcing ply is produced according to a weaving technique with weft threads and warp threads.

The volumized yarns are woven as weft yarns. The warp threads are non-voluminized roving threads.

The weft and warp threads are interlaced with each other according to a weaving weave adopted to make the web. In this way, the cohesion of the sheet is improved when faced with a risk of delamination.

The product obtained in the end is thinner than a product currently used, that is to say the ratio "Ms / e" is higher, "Ms" denoting the surface mass and "e" denoting the thickness. It therefore has a higher volume fraction of fibers.

As a weaving loom is used, the tablecloth is produced in a single operation, unlike the tablecloths assembled in a conventional manner. In addition, the width capacity of a weaving loom is greater and more flexible than that of the machines used to produce the assembled plies.

The tablecloths can be woven over a width of 2.50 to 3 meters, with a higher rate than using the assembled tablecloth technique.

Figures 2 to 4 schematically represent a sheet produced according to a first embodiment of one invention. This ply comprises in chain non-voluminized roving son 10 which are juxtaposed and extend in parallel.

These warp threads 10 are formed by synthetic fibers, for example glass, polyaramide or carbon, or a hybrid mixture of fibers. Good results have been obtained with glass strands of 1200 tex, but this is not limiting, and strands of 300 to 2400 tex or even strands having a greater linear density could be used.

In the weft direction, the wires 12 are voluminized roving wires. These strands are formed by glass fibers, the texturing of which in voluminized strands is well controlled. However, any other type of fiber capable of undergoing this texturing could be used.

Good results have been obtained with fibers of 220 to 320 tex. One could also use fibers having a greater linear density.

However, these figures are only indicative.

The tablecloth shown in Figures 2 to 4 was woven in a satin weave of eight, that is to say that the voluminized threads in the weft pass over seven consecutive warp threads and below the eighth. It goes without saying that the concept of top and bottom is quite relative, it must be taken only in relation to the representation of Figure 2. A satin weave of eight is a very flexible weave with a low embuvage, which ensures the both good mechanical properties of the ply and good cohesion of the ply faced with a risk of delamination.

According to the illustrated embodiment, two consecutive weft threads are offset by three warp threads, that is to say that two adjacent weft threads follow the same route with three shift threads, or five, depending on the direction of course considered.

The chosen weave, in this case the satin of eight and the mode of shift are not limiting, and one could choose another type of weave, for example a satin weave of four or five or other, or still a twill weave of two, four or whatever. What is important in fact is to have on the surface on at least one side of the sheet a good covering of volumized son which will be able to retain a good quantity of resin during the impregnation. What is also preferred is to have limited shrinking to preserve good mechanical properties of the web.

Thus, with reference to the embodiment illustrated in FIGS. 2 to 4, it is visible that the volumized wires are predominant on the face shown in FIG. 4, and that the non-voluminized roving wires are predominant on the other face represented in Figure 3. The fact that these non-voluminized roving yarns only bypass one out of eight weft yarns ensures interlacing of the layers with limited shrinking.

Good results have been obtained with areal masses of 30 to 100 g / m ² for the weft threads and from 540 to 960 g / m ² for the warp threads. These values are given for information only.

Optionally, in the direction of the weft, in addition to the volumized yarns, it is possible to add a few synthetic yarns for example of glass, polyester or other coated with a hot-melt resin which is made to adhere to the other yarns for example by a calendering operation on a hot drum. These threads are woven in the direction of the weft at the same time as the voluminized threads and after heating they reinforce the resistance of the sheet until it is impregnated with resin. Good results have been obtained with an areal mass of such threads of between 5 and 7 g / m ² . These values are given for information only.

During the manufacture of the ski, the handling of the resin-impregnated sheet is easy. Indeed, the two faces have a different aspect which makes it easy to identify them. In addition, the voluminized face being more hydrophilic than the other, it is less tacky to the touch than the other, which facilitates its handling or repositioning of the mold by an operator.

In the structure of the ski, if the ply is placed with the warp threads oriented in the longitudinal direction of the ski, the reinforcing ply has very good properties resistance to traction or compression in the event of flexing of the ski, due to its low shrinkage.

The structure of the ski has a very good resistance of the interlayer to delamination due to the interlacing of the weft and the warp.

Finally, the reinforcement ply is thinner than a traditional ply and lighter due to the absence of veil and binding wire. It therefore enables skis to be produced with a better weight / mechanical performance ratio.

As a variant of this embodiment, FIG. 5 schematically illustrates a reinforcing ply where the voluminized threads are predominant on each of the faces of the ply.

The ply shown comprises non-voluminized roving son 16 stretched parallel in the direction of the chain.

The threads stretched along the weft are voluminized roving threads 18 and 19.

It is visible in Figure 5 that a weft thread 18 passes over seven consecutive warp threads and below the eighth. The following weft thread 19 follows an opposite course and passes below seven consecutive warp threads and above the eighth, and so on.

Two consecutive weft threads 18 follow the same route with an offset of three or five warp threads, depending on the direction of travel considered.

Two adjacent weft threads 18 and 19 are diverted alternately every four warp threads.

Naturally the weaving of the threads can be carried out differently.

The sheet produced according to this embodiment has the same appearance on each of its faces. It also has on each of its faces a preponderance of voluminized threads which advantageously replace a veil. The non-voluminized threads which ensure the mechanical properties of the sheet are stretched in the direction of the chain between the two levels of voluminized threads. The intertwining of the wires also ensures good resistance to delamination. Figure 6 relates to another embodiment of one invention.

According to this embodiment, the weft comprises voluminized roving son 24 and non-voluminized roving son 25.

The chain includes, as in the previous cases, non-voluminized roving son.

This embodiment is suitable for producing a sheet of so-called bidirectional roving son, that is to say a sheet which has roving son capable of withstanding tensile and compressive stresses in two main directions having different orientations. This type of reinforcement is used in certain construction of skis, with preferably the warp threads oriented in the longitudinal direction of the ski, and the weft threads oriented transversely.

According to the illustrated embodiment, a non-voluminized weft thread 25 is alternated with two voluminized weft threads 24. This thread 25 passes over two adjacent warp threads, then below the third and so on.

Wire 24 follows the same route as in the previous cases.

Other modes of weaving such a web could also be suitable.

The double interlacing of the volumized and non-voluminized weft threads here ensures very good resistance of the reinforcing layer to delamination or peeling, with a relatively weak shrouding ensuring good mechanical properties of the reinforcement according to its two preferred orientations of resistance to traction or compression.

Naturally, the present description is given for information only and other implementations of the invention could be adopted without departing from the scope thereof.

In particular, other modes of weaving could be used, and also the variants or embodiments which have been described can be combined with one another.

Also, the invention is not limited to the reinforcing plies provided for the construction of a ski, it generally applies to the construction of any structure composite of gliding or rolling board type, and in particular cross-country skiing, snowboarding, gliding on water or skateboarding boards.

Finally we could reverse the weft threads with the warp threads.

Claims

1- Reinforcement sheet for a composite structure of the gliding or rolling board type comprising two sets of parallel roving wires oriented in different directions, the roving wires (12, 18, 19, 24, 25) in one of the directions being called weft yarns and the roving yarns (10, 16, 26) in the other direction being called warp yarns, at least part of the weft yarns being volumized yarns

(12, 18, 19, 24), the warp threads (10, 16, 26) being non-voluminized threads, characterized in that the voluminized threads (12, 18, 19, 24) of weft are interlaced with the warp threads (10, 16, 26).

2- reinforcement sheet according to claim 1, characterized in that all the weft son (12, 18, 19) are volumized son.

3- tablecloth according to claim 2, characterized in that the weft son (12, 18, 19) are woven with the warp son (10, 26) in a satin weave.

4- tablecloth according to claim 2, characterized in that the weft son (12, 18, 19) are woven with the warp son (10, 26) in a satin weave of eight.

5- tablecloth according to claim 3, characterized by the fact that the weft threads (18, 19) are woven with the warp threads (16) according to reverse paths so as to be predominant over one and the other of the sides of the tablecloth.

6- tablecloth according to claim 1, characterized in that the weft son (24, 25) comprise son (24) voluminized and son (25) non-voluminized.

7- tablecloth according to claim 6, characterized in that two voluminized weft son (24) intertwine warp son alternately with a non-voluminous weft thread (25).

8- tablecloth according to any one of the preceding claims, characterized in that the voluminized son

(12, 18, 19, 24) have a linear density between 220 and 320 tex.

9- tablecloth according to any one of the preceding claims, characterized in that the son not voluminized (10, 16, 25) have a linear density between 300 and 2400 tex.

10- composite board for the practice of sliding or rolling, characterized in that it has at least one reinforcing ply according to any one of the preceding claims.