FR2749519A1 - RECOVERY COMPLEX FOR SLIDING BOARD - Google Patents

Abstract

Complex for covering (1) mechanical structure of ski plate comprises at least one primary protective plastic layer (10) which makes up the external face of the ski which contains a secondary fabric layer of dry crosscut fibres (11). Secondary layer is stuck to primary layer and tertiary layer (12) which provides mechanical barrier between secondary layer and reinforcing resin of mechanical structure. Also claimed is plate coated with claimed complex.

Description

Gliding surface coating complex The present invention

  relates to a covering complex intended to complete the mechanical reinforcement structure of a gliding board. It relates more particularly to articles in the form of laminates comprising different composite materials such as skis in general,

  snowboards, monoskis and similar objects.

  In most cases, a gliding board consists of a mechanical assembly comprising the essential elements to withstand the various stresses in flexion, torsion and lateral deformations suffered by the board. These elements are generally reinforcing elements made of composite or metallic materials and filling elements serving as a core

  to keep the reinforcement elements at a distance.

  In order to protect this set of external aggressions and to make the product more attractive, the upper surface and the edges of the board are covered by a protective and decorative top generally consisting of one or more layers of plastic material decorated or not. However the role of this upper subassembly is limited to the protection against scratching, edging, UV, cleaning solvents, etc .; but it does not bring improvement

  particular in the behavior of the ski.

  The object of the present invention is to provide an improvement to the realization of a top of a gliding board which has in addition to its usual role, a damping role, participating in the attenuation of vibrations that

  disturb the conduct of the board.

  In particular, one of the advantages of the invention is to improve the vibratory behavior of the board by a predominant damping in torsion. Most of the damping devices reported or integrated damp the energy of flexural deformations of the board; which is not enough to keep a powerful, precise and regular contact on the snow. Thus, it has been found that the damping must be greater in torsion than in pure flexion to obtain a better contact of the ends of the board on the snow. The invention makes it possible to obtain a torsion / flexion damping ratio greater than the structures

  traditional gliding board.

  For this, the invention relates to a complex covering of a mechanical structure of a gliding board which comprises at least a first protective plastic layer intended to constitute the outer face of the gliding board, and a second layer of fabric cross-fiber dry; said second layer being bonded by bonding to said first protective plastic layer and finally a third barrier layer connected to the second layer by bonding and intended to constitute a mechanical barrier between said second layer and the resin

  reinforcements of said mechanical structure.

  Surprisingly, it has been demonstrated that the second layer of fiber fabric was able to dissipate energy by the friction caused by the fibers crossed between them, during deformations of the board; especially in torsion. The fiber is protected from the outside by the first plastic layer covering it. On the other hand, the third layer is a sealing barrier that allows the woven fiber of the second layer to remain dry at the time of the final assembly of the complex with the rest of the structure of the board, and in particular when the thermofluoric resin is in contact with the elements of

strengthening the structure.

  In addition to its cushioning role, the fiber fabric layer

  participates in the exterior decorative rendering of the complex.

  According to another characteristic of the invention, the third layer is formed by at least one textile nonwoven web whose face, intended to be connected to the mechanical structure of the board, is impregnated with a low viscosity hot melt polymer and low melting point. The melt polymer fills the interstices of the nonwoven layer and renders the assembly impervious to the thermofluible resin of the reinforcements. The nonwoven layer has the advantage of significantly improving the bonding value between the complex and the rest of the structure

of the gliding board.

  According to a complementary feature, the complex comprises a hot melt bonding film between the first protective plastic layer and the second dry fiber fabric layer and another hot melt bonding film between said second layer and the third barrier layer. The presence of films allows bonding between layers and thus offers a more

  wide choice of materials forming the respective layers.

  Other objects, features and advantages of the invention

  will emerge from the following description of the particular modes,

  FIG. 1 shows a cross-sectional view of the complex according to the invention before assembly with the rest of the structure of the board; FIG. 2 shows a cut-away view of the complex in FIG. highlighting the various layers constituting it, - Figures 3 to 5 show an embodiment of the complex according to the invention, - Figure 6 shows a gliding board covered with a complex according to the invention, - Figure 7 is a sectional view along AA of Figure 6, - Figure 8 is a variant of the gliding board of the

figure 6.

  FIGS. 1 and 2 show a complex 1 according to the invention intended to be attached to a mechanical structure 2 of a

gliding board.

  In this example, the complex 1 is represented in the form of a strip composed of a plurality of layers joined together

to each other.

  On the outer side (EXT) is placed the first layer of

  protection 10 intended to constitute the outer face of the complex.

  This layer is made of plastic and preferably of thermoplastic material. Preferably, it is a transparent sheet of thermoplastic material selected from the group consisting of polyamides, polycarbonates, ABS, polyethylene terephthalates (PET), polystyrenes. The layer may have a decorative pattern, for example a pattern made with inks

  sublimated 100 through the outer surface of the layer 10.

  This first layer must have sufficient thickness to protect the rest of the complex and absorb the thermodiffusion of the inks in depth. It must be greater than or equal to 0.3 mm; preferably of the order of 0.7 mm. Other decorating techniques can be used to replace sublimation. Examples include the use of screen printing, pad printing, hot stamping, etc. Of course, it is conceivable that the complex comprises several layers of protection. In this case, the layers can be assembled together beforehand by coextrusion

or by any other means.

  According to the invention, the second layer 11 of the complex is a dry fiber fabric. The fabric is preferably a weft and warp yarn fabric with 90 degree or less 90 degree crossing angles (multidirectional fabrics). The fabric contains no impregnating resin, at least heart, so as to promote friction between the

wires or strands.

  The thickness of this second layer may be between 0.2 and 0.7 mm. The grammage of the fabric can be between 200

and 1000 gm -2.

  This second layer may consist of a fabric of synthetic fibers chosen from glass, carbon, para-aramid,

  polyester or a mixture of these fibers.

  The third layer 12 is a barrier layer whose role is both to promote the bonding of the complex on the reinforcing structure and to prevent the impregnation of the second layer by the thermofluable resin of the reinforcing layer 20

during the final assembly.

  This layer 12 is therefore preferably formed by a nonwoven fabric web 120 whose face intended to be connected to the mechanical structure of the board is impregnated with a hot melt polymer 121 with low viscosity and low melting point. The polymer can fill the interstices of the nonwoven web

  and make it waterproof to the resin reinforcements.

  Among the polymers that may be suitable, it will be preferable to choose them from ionomers; in particular, those having a MFI (Melt Flow Index) value of less than or equal to 7 and a melting point of less than or equal to 110 degrees Celsius. The nonwoven textile web also has the advantage of folding and

  stretch easily and without breaking.

  The nonwoven textile layer associated with the impregnating polymer also constitutes an opaque background for revealing the

decor of the complex.

  To achieve the cohesion of the complex, a hot melt bonding film 130 is interposed between the first plastic layer 10 of protection and the second layer 11 of dry fiber fabric and another hot melt adhesive film 131 between

  said second layer 11 and the third barrier layer 12.

  The bonding films 130, 131 are preferably based on a polymer or copolymer grafted with a carboxylic acid action,

  anhydrous carboxylic acid or carboxylic acid ester.

  The film may advantageously be grafted polyethylene, and more specifically, polyethylene grafted with maleic anhydride. By choosing the nonwoven textile web and by associating it with a hot-melt film of the type designated, we obtain bonding values much higher than those obtainable with any other substrate, such as

plastic layer for example.

  The bond strength at the interface between the second layer 11 and the reinforcing structure 20 is of the order of 20 N in the presence of the nonwoven layer 120. The resistance is only 4 N without the layer non-woven, however, preserving the only presence of films 131 and 121 (and zero resistance

  after aging in an aqueous medium).

  The bond strength at the interface between the second layer 11 and the first plastic layer 10 is of the order of 12 N

  approximately with the presence of the bonding film 130.

  In addition to its role as a barrier layer, the third layer 12 prevents the chemical modification of the bonding film 131 by the resin reinforcements when the film is in particular a film.

  ionomer that can react with epoxides.

  Figures 3 to 5 illustrate, by way of example, a method of manufacturing the complex 1 described above. According to FIG. 3, the first step is to print a decor by heat transfer of sublimable dyes contained in a sheet of backing paper 3. The sheet is applied in contact with the surface of the plastic layer 10 and in a manner known per se, heat and pressure are applied to

  obtain the diffusion of the dyes through the layer 10.

  The operating conditions of the decoration cycle are

  example of 165 C for 2 minutes at 2 bar.

  The next step is to stack the complex; respectively, of the first plastic layer 10 thus decorated, of the adhesive film 130, of the second fabric layer 11, then of the other adhesive film 131, of the third layer formed of the nonwoven textile web 120 and the movie of

hot melt polymer 121.

  A press cycle is then applied by applying a pressure of the order of 2 to 4 bars and a temperature of 150 to

  degrees for about 1 to 2 minutes.

  An alternative is to pre-assemble a part

  of the complex by hot calendering. For example, the sub-

  together formed by the film 130, the second layer 11, the film 131, the third layer 12 may be hot calendered at first, and then assembled to the plastic layer by

pressing in a second time.

  The complex thus formed is thus ready for use for the final assembly with the rest of the structure of the gliding board which comprises in particular the reinforcement elements in prepregs. Final assembly is an operation which consists in molding the structure to the desired shape while obtaining the adhesion of all the components between them. The operation is done in a mold of appropriate shape to the desired final shape which is heated to a temperature sufficient to obtain the cooking of the elements.

reinforcement prepregs.

  When baking in a mold, the resin prepreg reinforcements reaches a temperature of about 150 C and becomes fluid. Due to the pressure exerted in the mold, of the order of 7-10 bar, the resin tends to flow in the spaces and interstices left free. This creep is stopped in the direction of the complex thanks to the barrier layer 12. The resins most often used for prepregs in the field of ski and snowboard manufacturing are resins

  thermosetting epoxy type.

  The invention also relates to the gliding board provided with a complex as described above. In the case of FIGS. 6 and 7, the gliding board is provided along its entire length with

  complex 1 which covers the mechanical structure 2.

  This structure 2 comprises an upper reinforcing element or layer 20, a central core 21, a lower reinforcing element or layer 22, lateral metal edges 230, 231

  and a sliding sole 24, generally made of polyethylene.

  The elements 20, 22 are advantageously based on

  reinforcement and thermosetting epoxy resin.

  The core is made of a low density but compression resistant material such as foam, wood or honeycomb. According to the invention, the complex is assembled on the structure 2 so that the third layer 12 constituting the mechanical barrier is bonded by bonding in contact with the reinforcing layer 20 based on fibers impregnated with a flowable resin.

  hot belonging to the mechanical structure 2.

  In the example of Figure 6, the fibers or son of the fabric layer occupying the entire length of the board are oriented and intersected substantially in a direction inclined at + and - 45 degrees relative to the longitudinal direction II 'of the board. Damping measurement tests have found that the ratio between the first torsion and the third bending in the corresponding frequency range, of the order of Hertz, is greater for boards gliding using the complex of the invention only for boards of traditional structure. It is measured that this ratio is in any case greater than 1 and of the order of 1.05 for a box structure ski with all-fiber reinforcements and of the order of 1.42 for a fiber-box structure ski. metal. For a traditional structure, the ratio is of the order of 0.75 for a ski type reinforcements all fiber and of the order of 0.70 for a fiber reinforced ski fibro-metal. It can be seen that these skis which have a ratio greater than 1 have a snow behavior which can be described as milder thanks to a better surface contact.

glide / snow.

  In the example of FIG. 8, the gliding board shown is a ski which has a central portion 30 corresponding to the attachment mounting zone, a front zone 31 extending between the front limit of the central portion 30 and the spatula and a rear area 32 extending between the limit

  rear of the central portion 30 and the heel of the ski.

  In this case, it is expected that the second layer of dry fibers is present only in the front zone 31 and the rear zone 32 to provide predominant torsional damping in these areas which are particularly stressed and more than the central portion. In the central portion, the layer 11 may be replaced by an additional plastic layer of the same thickness in the complex for example. In a variant, the layer 11 may also not be replaced by an additional layer. Of course, the invention is not limited to the embodiments thus described and includes all the equivalents

  which may fall within the scope of the claims which

follow.

Claims (8)

  1-Complex covering (1) a mechanical structure (2) of a gliding board comprising at least a first protective plastic layer (10) intended to constitute the outer face of the gliding board, characterized in that it comprises a second layer of crossed dry fiber fabric (11); said second layer being adhesively bonded to said first plastic protective layer (10) and a third barrier layer (12) bonded to the second layer (11) by gluing and for providing a mechanical barrier between said second layer (11) and the resin reinforcements of said mechanical structure.   2- covering complex according to claim 1, characterized in that the third layer (12) is formed by at least one nonwoven textile web (120) whose face intended to be connected to the mechanical structure of the board is impregnated a low viscosity hot melt polymer (121) and low melting point.   3- coating complex according to claim 2, characterized in that the hot melt polymer (121) is chosen among the ionomers.   4- coating complex according to claim 1, 2 or 3, characterized in that it comprises a hot-melt bonding film (130) between the first protective plastic layer (10) and the second layer of dry fiber fabric (11). ) and another hot-melt gluing film (131) between   said second layer (11) and the third barrier layer (12).   - Coating complex according to claim 4, characterized in that the bonding films (130, 131) are based on a polymer or copolymer grafted by the action of carboxylic acid, carboxylic acid anhydride or polyester ester. carboxylic acid. 6- Recovery complex according to any one of   preceding claims, characterized in that the first   layer (10) is a transparent sheet of thermoplastic material selected from the group consisting of polyamides, polycarbonates, ABS, polystyrenes,   polyethylene terephthalate (PET).   7- Recovery complex according to any one of   preceding claims, characterized in that the second   layer (11) is made of a synthetic fiber fabric selected from glass, carbon, para-aramid, polyester or a mixture of these fibers.   8- Gliding board comprising a mechanical structure of reinforcement (2) based on heat-flowable resin, characterized in that it is provided over part of its length at least one covering complex (1) according to the any of   preceding claims; the third layer (12)   constituting the mechanical barrier being bonded by bonding in contact with a reinforcing layer (20) based on fibers impregnated with a heat-transferable resin belonging to the structure mechanical (2).   9- gliding board according to claim 8, characterized in that the fibers of the second layer (10) are oriented and crossed substantially in a direction inclined to + and -   degrees to the longitudinal direction of the board.   - gliding board according to claim 9, characterized in that the second layer of dry fiber fabric (11) is present in the complex over a part of the length of the board only.   11- gliding board according to claim 10, characterized in that the second layer of dry fibers (11) is present in the front zone (31) and the rear zone (32) outside the central portion (30) corresponding to mounting area of the fixings.