FR2663237A1 - METHOD FOR GLUING ELEMENTS OF THE STRUCTURE OF A SKI. - Google Patents

Abstract

The invention relates to a method of bonding the structural components of a ski, consisting in assembling at least a first element (1) and a second element (2) by the action of a layer of adhesive bonding material (5), of resin or of foam, interposing at least between the layer of adhesive bonding material (5) and the junction surface of the first component (1) a thermoplastic film (6), suitable for bonding, composed of a mixture of one or more thermoplastic elastomer(s) based on polyamide and of an olefin copolymer consisting of at least two different olefin monomers. The mixture is such that the thermoplastic elastomer(s) represents (represent) at least 50 % and preferably at least 60 % of the total weight of the mixture.

Description

METHOD FOR GLUING ELEMENTS OF THE STRUCTURE OF A SKI

  The present invention relates to films capable of bonding, thermoplastics composed of a mixture of thermoplastic elastomer (TPE) based on polyamide and of modified olefin copolymer, as well as the method of bonding elements of the structure d '' a ski using

said thermoplastic films.

  In thermoplastic films, there are in particular "hot melts" films. Mention may be made of the adhesives described in application FR 2 523 143, and the composition of which contains copolymers based on ethylene (at least 35% by weight) and d '' at least one vinyl ester and

  1 O containing 0.5 to 20% of a copolyetheresteramide.

  In European patent application No. 312 968, the use of “hot melt” bonding films has been described for the assembly of elements of the structure of a ski. These films are mainly composed of a thermoplastic polymer and d '' a membership promoter such

  than a silane or an epoxy resin.

  I 5 The object of the present invention is to provide a film of new composition, suitable for bonding, having improved adhesion properties and which can be applied to a more

wide range of materials.

  Another object of the invention is to improve the thermal resistance of the bonding of the laminate thus formed. 2 0 Finally, the films of the invention are more costly to manufacture and use.

  economical than those currently known.

  The present invention therefore relates to thermoplastic films or sheets, suitable for bonding, composed of a mixture of thermoplastic elastomer (s) (TPE) based on polyamide and of a modified olefin copolymer consisting of at least two different olefin monomers; said mixture being such that the thermoplastic elastomer (s) represents (s) therein (s)

  at least 50% and preferably at least 60% of the total weight.

  Polyamide based thermoplastic or TPE elastomers can be

  random or block copolymers.

  The copolymers are formed by the random sequence of the various constituents (monomers and / or prepolymers) while the block copolymers or blocks preferred by the applicant, are formed from blocks having a certain chain length of their

various constituents.

  The polyamide-based copolymers according to the invention are either polyesteramides or

polyetheramides.

  Block polyetheramides or polyether block amides can in particular result from the copolycondensation of polyamide sequences with reactive ends with polyether sequences with reactive ends, such as, inter alia: a) polyamide sequences at the ends of diamine chains with polyoxalkylene sequences

  at the ends of dicarboxylic chains.

  b) Polyamide sequences at the ends of dicarboxylic chains with polyoxyalkykene sequences at the ends of diamine chains obtained by cyanoethylation and hydrogenation of alpha, omega, dihydroxylated aliphatic sequences called polyetherdiols. c) polyamide sequences at the ends of dicarboxylic chains with polyetherdiols,

  called polyetheresteramides particularly preferred by the applicant.

  The composition and manufacture of such polyetheresteramides have been described in the

  French patents No. 2,273,021 and 2,401,947, the content of which is added to the present description.

  The number-average molecular mass of these polyamide blocks is generally 1 O between 500 and 10,000 and more particularly between 600 and 5,000 The polyamide blocks of the polyetheresteramides are preferably formed from aliphatic polyamides and / or from amorphous polyamide or from copolyamide resulting polycondensation of their monomers. The number average molecular weight of the polyethers is generally between

  1 5 200 and 6000 and more particularly between 600 and 3000.

  The polyether blocks most often consist of polytetramethylene glycol (PTMG),

  polyethylene glycol (PEG) and / or polypropylene glycol (PPG).

  The inherent viscosity of polyetheresteramides is advantageously between 0.8 and 2.05 It is measured in metacresol at 20 C with an initial concentration of 0.5 g of

  20 polymer per 100 g of metacresol.

  The polyetheresteramides can be formed from 5 to 85% by weight of polyether, from 95 to% by weight of polyamide, and preferably from 30 to 85% by weight of polyether and from 70 to 15

% by weight of polyamide.

  The polyetheresteramides preferred by the applicant are those whose polyamide sequences are essentially made up of PA-11, 12 and / or 12 12 and when a composition having antistatic properties is sought, polyetheresteramides whose sequences are preferably used polyethers are basically made up of

polyethylene glycol (PEG).

  The second compound used in the composition of the film is a copolymer of olefins

  Modified consisting of at least two different monomers of olefins.

  The olefins represent at least 50% and preferably at least 60% of the total weight of the copolymer, it being understood that the copolymers can be polymerized in a statistical or sequenced fashion and have a linear or branched structure, for the polyolefins modified according to the invention. Among the copolymers which are particularly preferred by the applicant, mention will be made most particularly of the copolymers of ethylene and of propylene grafted with a carboxylic acid.

  or anhydrous carboxylic acid or an acid salt.

  Among the acids, the unsaturated dicarboxylic acids will be chosen more particularly, such as maleic, fumaric, itaconic acid for example. The anhydrous and salts chosen are

  4 0 those corresponding to the acids mentioned of course.

  Mention may also be made, among these copolymers: of ethylene / propylene / maleic diene

(EPDM).

  The films or sheets particularly preferred by the applicant consist of a mixture of polyetheresteramide at least 50% by weight (preferably 60%) and of ethylene propylene copolymer containing 0.1 to 2% by weight of maleic anhydride graft. Various other components can be incorporated into the compositions of the films described above.

  such as fillers, pigments or dyes, various additives.

  By way of example of fillers, mention may be made of glass fibers, carbon fibers, aramid fibers, talc, silica, kaolin, glass beads and fibers, ceramics, metallic fillers, 1 O salts and metal oxides, such as aluminum powder, calcium carbonates and

  manganese, ferrite powder, titanium oxide.

  In general, up to 50% and preferably up to 40% by weight of fillers can be incorporated relative to the compositions of thermoplastic elastomer (s) and of copolymer

modified olefins.

  By way of example of additives, mention may be made of anti-UV agents, release agents,

shock modifiers.

  The films or sheets according to the invention are obtained according to any known extrusion process such as extrusion-calendering flat, extrusion plastering, extrusion blow molding, temperature

  being generally between 190 and 250 C.

  2 O According to Modern Plastics Enclopedia, the term "film" is reserved for objects of planar section whose thickness is less than 250 microns and the term "sheet" for objects of greater thickness and up to several mm, but in all that follows, and for reasons of simplification, we can use run or the other of the terms to simultaneously designate films

and leaves.

  The films according to the invention can be used as they are but can also be used in the manufacture of multilayer films obtained for example by co-extrusion, laminating

hot.

  Single-layer films are particularly suitable for bonding to non-woven fabrics and materials

  woven, covered with natural or synthetic fibers, foam.

  3 O The multilayer films particularly preferred by the applicant comprise: a layer of aliphatic polyamide (such as PA-6, PA-6 6, PA-11, PA-12, PA-12 12), of amorphous polyamide of elastomer thermoplastic based on polyamide and / or copolymer of ethylene and vinyl alcohol (EVOH)

a film according to the invention.

  These films can be bonded to rigid parts and in particular to metal parts (such as cables, sheets) as well as to synthetic materials preferably based on,

  covered or impregnated with epoxy resin (s) and / or polyester (s) and / or polyurethane (s).

  The process for manufacturing these composite materials generally takes place in two stages: First, the co-extrusion of the bilayer film is carried out and then hot glued on the side of the composition layer according to the invention, on the support. in synthetic material for example,

  by hot forming or thermoforming.

  These composite materials can be decorated using the sublimable ink transfer printing method and in particular according to the methods described in patent application FR 2 596 286. The decoration of these materials can also be implemented using other techniques such as only by screen printing, painting or varnishing, hot transfer, pad printing,

inkjet, laser marking.

  The composite materials consisting of the two-layer film described above and of a support 1 O impregnated with epoxy resin (s) and / or polyester and / or polyurethane possibly decorated are particularly suitable for the production of ski tops , windsurfing, skateboarding, surfboard, boat hulls, decoration panels for bottom of bodywork

  automotive, anti-noise laminates or thermal insulation.

  Monolayer films can also serve as co-extrusion binder for multilayer films allowing adhesion of layers whose bonding is difficult or even impossible. By way of example, mention may be made of the use of films of composition according to the invention as coextrusion binder of a film based on polycarbonate (PC) on the one hand and of a film to

  based on copolymer of ethylene and vinyl alcohol (EVOLI) on the other hand.

  The present invention also relates to the method of manufacturing a ski used in winter sports and more particularly to the bonding of elements of the structure of a ski, and to a ski.

obtained according to this process.

  The composite nature of a ski structure leads to skiing by assembling several elements previously coated or impregnated with a thermosetting adhesive of the epoxy, polyester or polyurethane foam type, for example. Naturally, this adhesive must be compatible with all the elements to be assembled These binders are generally not sufficient to adhere all the materials that one wishes to use in the composition of a ski To obtain adhesion on certain materials, it is therefore proposed to use the bonding films

thermoplastics of the invention.

  This composite structure manufacturing process comprising a step of assembling at least a first element and a second element by the action of a layer of resin glue or foam between the joining surfaces of the two elements is characterized by the fact that a film is interposed at least between the adhesive layer and the junction surface of the first element

  of thermoplastic bonding of the invention.

  Other objects, characteristics and advantages will emerge from the description of the modes of

  particular embodiment, made in relation to the attached figures, among which: FIGS. 1 to 4 illustrate a method of assembly by gluing according to a first embodiment of the invention; Figures 5 to 6 illustrate a method of assembly by gluing according to a second embodiment of the invention; Figures 7 and 8 illustrate a method of assembly by gluing according to another embodiment. In the embodiment shown in Figures 1 to 4, the method of the invention allows the assembly of a first element 1 and a second element 2, according to their respective junction surfaces 3 and 4, by means of 'a layer of adhesive 5 interposed between said joining surfaces 3 and 4 The second element 2 is assumed to be compatible with the adhesive 5, that is to say that the adhesive 5 has good adhesion on the second element 2 On the other hand, the first 1 O element 1 is made of a material which may not have good compatibility with the adhesive 5, that is to say that the adhesive 5 does not have good adhesion on the junction surface.

3 of the first element 1.

  To allow the assembly of the first element 1 with the second element 2, the first element 1 not having a good adhesion power with the adhesive 5, one interposes between the layer 1 5 of adhesive 5 and the junction surface 3 of the first element 1 a film 6 composed of a mixture of the invention, that is to say a mixture of thermoplastic elastomer (s) based on polyamide and of modified olefin copolymer; said mixture being such that the elastomer (s)

  thermoplastic (s) therein represents at least 50% of the total weight of the mixture as defined before.

  As regards the presence of the adhesive 5, a first possibility, represented in FIGS. 1 to 4, consists in coating the joining surface 4 of the second element 2 with an adhesive 5, as shown in FIG. 3, before assembly by pressing the adhesive layer 5 against the

  film 6 and obtaining the assembly shown in FIG. 4.

  A second way of ensuring the joining between the film and the second element 2 can be provided in the case where the second element 2 comprises a junction surface 4 based on thermosetting resin which is not fully crosslinked. special case, a reinforcing element pre-impregnated with resin It is then possible to apply the junction surface 4 of the second element 2 directly against the film 6, and, by heating, the resin which is not entirely crosslinked from the second element 2 provides even the bonding function, adhesion being obtained

  by additional crosslinking of said resin.

  The resins generally used are epoxy resins, or polyesters or polyurethane. It is advantageous to use a film 6 based on polyetheresteramide at least 50%,

  preferably 60% by weight, and of maleized ethylene propylene (EPR) copolymer.

  This embodiment makes it possible, for example, to ensure the bonding by an epoxy adhesive, a polyester or polyurethane adhesive of a first element 1, the junction surface of which is made of the following materials: polyamide, polyethylene, polyethylene terephthalate,

  polybutadiene terephthalate, polypropylene, treated aluminum, aluminum alloy or steel.

  For example, the use of a film 6 of the invention allows the bonding of a first element 1 consisting of a polyamide film 11 for example by an adhesive 5 made of epoxy resin on a support 2 L ' element 1 can advantageously be used as an upper element for decorating and protecting a ski for example In this particular case, the support 2 can be a mechanical reinforcement element consisting of a reinforcing textile sheet woven or not made of fiberglass , carbon, aramid or other, or a metallic reinforcing element made of steel, aluminum or an alloy. In the embodiment represented in FIGS. 1 to 4, the assembly is carried out in successive stages: during a first stage illustrated in FIGS. 1 and 2, assembly is carried out by calendering or hot pressing, or co-extrusion , the film 6 on the junction surface 3 of the first element 1 having a lack of adhesion with the adhesive 5; the temperature must be 1 O high at the softening point of the film; during a second step, the adhesive 5 is applied to the junction surface 4 of the second element 2, as shown in Figure 6; during a third step, the layers formed by the adhesive and the film 6 are applied against each other, carrying out the assembly as shown in FIG. 4. In the embodiment shown in FIGS. 5 and 6, arranges all the elements 1 5 in a mold, that is to say in order: the first element 1, the film 6, the layer of adhesive 5, the second element 2; by hot pressing, all the elements are applied one on the other, and the assembly is carried out in one step The assembly temperature must also be high

  at the softening point of the film.

  A third embodiment of the invention represented by FIG. 7 consists in assembling elements of the structure of a ski 1 and 2 by injection of a thermosetting foam 5 of polyurethane and expandable type. The foam 5 not being compatible with all the elements to be assembled, adhesion is therefore ensured by the interposition of a bonding film 6 between the foam and the element to be bonded.

  element 1 of ski structure, a bonding film 6 then a second element 2 in a mold 8.

  Then, the polyurethane foam 5 is injected which, after its expansion and then hardening phase, adheres perfectly to the bonding film 6 and to the first element 1 The heat released by the exothermic reaction generally suffices to carry the bonding film at its softening point and cause bonding to the structural element. However, it is of course possible to provide additional heat after or during the molding operation. Of course, the arrangement of 'a bonding film 6 according to the invention between the foam 5 and the second element 2 when the latter also does not represent any adhesion power or a weak adhesion power with the foam In this case, provision can be made for the film is in the particular form of a tubular envelope 61 into which the foam 5 is injected, as shown in FIG. 8 The tubular envelope 61 a

  for advantage of ensuring impermeability to a possible overflow of the foam.

  It will be understood that the present invention is not limited to the particular embodiments which have been explicitly described and that its scope includes the various methods of bonding elements in other applications covering other fields such as those of automotive equipment, anti-noise or thermal insulation laminates, shoe soles, wetsuits, etc. By way of example, mention may be made of the application of the use of these bonding films to the production of products in foam covered with fabrics according to the known technique of "Foam baking" A fabric / film complex is firstly produced in a machine for laminating at least one layer of fabrics, and of a film according to the invention, and optionally a layer of foam The complex thus produced is placed in a mold and a thermosetting type foam, preferably polyurethane, is injected. The "in situ" expansion reaction of the

  constituents of the foam causes adhesion to the complex.

  1 O The following examples illustrate the invention without however limiting it: Unless otherwise indicated in all that follows, the proportions of the constituents are

data by weight.

Example I

  1 5 In a single-screw extruder, the screw speed of which is set at 33 rpm, 80 parts of polyetheresteramide (A 1) and 20 parts of ethylene-copolymer are compounded.

maleised polypropylene (B 1).

  The extrusion temperature is between 200 and 220 C and the flow rate of the extruder is

set at 30 kg / h.

  2 0 At the end of the die, the composition obtained in the form of rods with an average particle size equal to approximately 3 mm has a Melt Index (MI) of 1.31 measured at 190 ° C. under a load of 2.16

kg according to ASTM D 1238.

  The polyetheresteramide (A 1) used consists of 88% of PA-12 sequences

  (Mn = 1000) and 12% of PTMG sequences (Mn = 1000).

  2 5 The maleized EPR used contains 70% ethylene Its total anhydride level is understood

  between 1.08 and 1.5% and its Melt Index (measured at 230 C under a load of 10 kg) is equal to 9.

  The film of composition I is then extruded. The extrusion conditions are as follows: extrusion temperature: 184 C / 206 C / 215 C 3 O channel temperature: 231 C / 236 C die temperature : 228 C / 236 C

  The screw speed is 80 rpm and the drawing speed is 20 m / min.

  At the outlet of the die, a film of thickness equal to approximately 50 μm is obtained.

  3 5 Example II Under the same conditions as in I, a composition II is composed of 70

  parts of polyetheresteramide (A 2) and 30 parts of EPR m (B 1).

  Polyetheresteramide B 2 consists of 88% of PA-12 sequences (Mn = 5,000) and

  12% PTMG sequences (Mn = 650).

  Then a film of composition II is extruded under conditions identical to those described in I.

Example III

  Under the same conditions as in I, composition III is composed of 90

  parts of polyetheresteramide (A 2) and 10 parts of EPR m (B 2).

  The EPR m (B 2) used contains 50% ethylene Its total anhydride level is equal to

  1.26% and its Melt Index (measured at 230 C under a load of 2.16 kg) is equal to 3.

  The Shore D hardness (5 s) of III, measured according to ISO 868, is equal to 60.6.

  1 O The tensile breaking stress, measured according to standard ASTM D 638, is equal to

, 9 M Pa.

  The flexural modulus at 20 C, measured according to ASTM D 790, is equal to

357 M Pa.

  Tear resistance, measured according to ISO standard 34, (tear parallel to

  1 5 injection) is 147.4 k N / m.

  Then a film of composition m I is extruded under the same conditions as those described in I.

Claims (1)

CLAIMS 1 Method for bonding elements of the structure of a ski comprising a step of assembling at least a first element (1) and a second element (2) by the action of a layer of glue, resin or a foam (5) between the joining surfaces (3,4) of the two elements, characterized in that at least one interposes between the adhesive layer (5) and the joining surface (3) of the first element (1 ) a thermoplastic film (6) suitable for bonding, composed of a mixture of thermoplastic elastomer (s) based on polyamide and of a modified olefin copolymer consisting of at least two different olefin monomers ; said mixture being such that the thermoplastic elastomer (s) represents (s) at least 50%, and preferably at least 60% of the total weight of the mixture. 2 Method according to claim 1, characterized in that the olefin copolymer is a copolymer of ethylene and propylene grafted with a carboxylic acid, an anhydrous acid or a salt. 1 5 3 A method according to claim 1, characterized in that the olefin copolymer is an EPDM. 4 Method according to claim 1, characterized in that the thermoplastic elastomer (s) based on polyamide is a random or block copolymer. Process according to Claim 4, characterized in that the block copolymer is a polyetheresteramide in which the polyamide blocks have an average molecular weight of between 500 and 10,000, and more particularly 600 and 5,000, and the polyethers have an average molecular weight of also between 200 and 6000 and more particularly 600 and 3000. 6 Method according to claim 2, characterized in that the ethylene-propylene copolymer contains 0.1 to 2% by weight of grafted maleic anhydride. 7 Method according to any one of the preceding claims, characterized in that the film (6) contains fillers, pigments, dyes or additives. 8 A method according to any one of the preceding claims characterized in that one uses an adhesive (5) thermosetting epoxy and / or polyester and / or polyurethane. 3 O 9 Method according to claim 8, characterized in that the adhesive (5) and the second element (2) constitute a prepreg assembly not fully crosslinked. Method according to claim 7 or 8, characterized in that the joining surface (3) of the first element (1) consists of the following materials: polyamide, polyethylene, polyethylene terephthalate, polybutadiene terephthalate, polypropylene, treated aluminum, aluminum alloy or steel. 11 Method according to claim 10, characterized in that the first element (1) is a polyamide film 11. 12 Method according to claim 11, characterized in that the first element (1) constitutes the upper element for decoration and protection of a ski. 13 Method according to claim 11, characterized in that the element 1 and the film (6) are produced in a single step by coextrusion. 14 Method according to any one of claims 1 to 7, characterized in that the assembly step consists in: first placing the first element (1), the bonding film (6) then the second element (2) in a mold (8), then injecting an expandable polyurethane foam (5) which, after its expansion phase, then hardening, adheres perfectly to the bonding film (6) and to the first element (1).   1 O 15 Ski obtained from the bonding process according to any one of claims l to 14.