FR3060439A1 - METHOD FOR MANUFACTURING A FLEXIBLE ARTICLE WITH SHAPE MEMORY, LAMINATE OBTAINED DURING THE IMPLEMENTATION OF THE MANUFACTURING METHOD AND MEMORY DEFORMABLE ARTICLE - Google Patents

Abstract

A method of manufacturing a deformable shape memory article (1), the manufacturing method comprising: - an assembly step in which a laminate (5) is made, the laminate having a plurality of structural layers ( 6) presenting respective facing surfaces, and at least one bonding layer (7) interposed between the fastening surfaces of the structural layers (6), the structural layers (6) consisting of an elastically deformable material , the bonding layer (7) comprising a viscoel adhesive substance (8) which is crosslinkable in elastomer and extends over at least a portion of the bonding surfaces of the structural layers (6), - a forming step in which the laminate (5) is bent to obtain the shape of the article (1) and the adhesive substance (8) of the bonding layer (7) undergoes crosslinking.

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number:

(to be used only for reproduction orders)

©) National registration number

060 439

62791

COURBEVOIE © Int Cl ⁸ : B 29 C 65/02 (2017.01), B 29 C 53/04, 65/52, B 32 B 7/12, B 27 H 1/00, B 27 G 11/00

A1 PATENT APPLICATION

©) Date of filing: 19.12.16. (© Priority: (© Applicant (s): OBSESS Simplified joint stock company - FR. ©) Date of public availability of the request: 06.22.18 Bulletin 18/25. @ Inventor (s): ESCOFFIER ARTHUR and JIGUET CYRIL. ©) List of documents cited in the preliminary search report: See the end of this booklet (© References to other related national documents: ©) Holder (s): OBSESS Simplified joint-stock company. ©) Extension request (s): © Agent (s): CABINET PLASSERAUD.

METHOD FOR MANUFACTURING A FLEXIBLE SHAPE MEMORY ARTICLE, LAMINATE OBTAINED DURING THE IMPLEMENTATION OF THE MANUFACTURING METHOD AND DEFORMABLE ARTICLE WITH SHAPE MEMORY.

FR 3 060 439 - A1

Method for manufacturing a deformable article (1) with shape memory, the manufacturing method comprising:

- an assembly step during which a laminate (5) is produced, the laminate comprising a plurality of structural layers (6) having respectively facing facing surfaces, and at least one interlocking layer (7) interposed between the fastening surfaces of the structural layers (6), the structural layers (6) being made of an elastically deformable material, the fastening layer (7) comprising an adhesive substance (8) viscoel asti that crosslinkable in elastomer and extended over at least part of the joining surfaces of the structural layers (6),

- A forming step during which the laminate (5) is bent to obtain the shape of the article (1) and the adhesive substance (8) of the bonding layer (7) undergoes crosslinking.

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Method for manufacturing a flexible article with shape memory, laminate obtained during the implementation of the manufacturing process and deformable article with shape memory

The invention relates to a method for manufacturing a flexible shape memory article, to a laminate obtained during the implementation of the manufacturing process and to a deformable article with shape memory. By deformable article with shape memory is meant here an article having a certain shape in 3D and able to deform elastically and return to this shape in 3D after elastic deformation.

Deformable articles with shape memory, such as, for example, ski mask frames, diving fins, plastic chairs and the like, are generally made by molding plastic material. Such a manufacturing method allows great flexibility in the products obtained, in particular in terms of shapes and dimensions (eg adaptation to the morphology, etc.). On the other hand, it requires the design of expensive and complex molds in particular because they require a surface condition with very low roughness. These molds are also associated with heavy and expensive production tool installations. This manufacturing method is not suitable for small or medium series. It also offers little flexibility in the implementation of the manufacturing process. Furthermore, the items resulting from this manufacturing process have little geometric customization due to the need to mass produce and do not enjoy a quality image due to the material used.

To improve this image, there are articles mainly made of wood, that is to say more than 50% of wood. These articles find many applications in a wide variety of fields such as construction, furniture, fashion or sport. From the consumers' point of view, these articles are experiencing a craze not only for the feelings of well-being they can provide but also for the image of respect for the environment which they can send back. Thus, on sight or touch, wood can give a reassuring impression of comfort and robustness. The smell of wood can evoke memories. Wood is, moreover, a natural, renewable and recyclable resource. From the manufacturers' point of view, these items also have a number of advantages in terms of mechanical properties and costs.

To obtain wooden articles of complex shapes in 3D, the wood matrix must be completely destructured following a long, complex and expensive process and then the different layers of wood are glued with a rigid adhesive and the article n 'has more elasticity, it is therefore not shape memory within the meaning of the invention. For unstructured molded wooden articles, the product obtained is rigid and / or in the case of a plate product, it can bend but returns to the plate position as soon as the force is removed, in other words the product cannot keep a given shape, notably 3D, other than planar. The preceding articles in shape, are generally obtained by processes at high bending pressures, between molds and counter-molds of steel, having drawbacks analogous to those mentioned above for the manufacture of plastic articles.

The invention aims to overcome the problems mentioned above.

To this end, according to a first aspect, the invention provides a method of manufacturing a deformable article with shape memory, the manufacturing method comprising:

- An assembly step during which a laminate is produced, the laminate comprising a plurality of structural layers respectively having facing joining surfaces, and at least one joining layer interposed between the joining surfaces of the structure layers , the structure layers being made of an elastically deformable material, the bonding layer comprising a viscoelastic adhesive substance crosslinkable in elastomer and extended over at least part of the bonding surfaces of the structure layers,

- A forming step during which the laminate is bent to obtain the shape of the article and the adhesive substance of the bonding layer undergoes crosslinking.

Thus, the article can be obtained simply and quickly by molding the laminate comprising a viscoelastic adhesive substance which can be crosslinked into an elastomer. The article comprises the curved laminate, that is to say which has at least one curvature in at least one plane and generally several curvatures in several planes and / or in different directions, obtained by molding and kept in shape by the adhesive substance. Such an article has, at rest, a non-planar 3D shape with curvatures in very different directions and an outline while being deformable with shape memory.

The crosslinkable viscoelastic adhesive substance made of elastomer is little or not subject to creep and allows relative sliding of the structural layers and thus shearing in the laminate from which it results a residual flexibility while allowing shaping in 3D. Its implementation makes it possible to bond at low pressure and with controlled thickness and to better manage the mechanical properties, in particular of flexibility and elasticity, of the laminate and of the resulting article. The mechanical properties of the laminate can be modulated either locally or throughout the laminate.

The resulting article has a number of advantages, among which a conservation of elastic deformations after shaping and damping of vibrations. Furthermore, the manufacturing process can be easily implemented with inexpensive low pressure molding equipment and process.

We actually get an article with the same characteristics as a molded plastic article, while being of better quality (in wood), more aesthetic and richer.

During the assembly step, the bonding layer can be interposed between the bonding surfaces before crosslinking of the adhesive substance and, during the forming step, the structural layers of the laminate can be deformed before crosslinking of the adhesive substance. The article formed from the curved laminate, that is to say having at least one curvature in at least one direction, can be recovered after crosslinking of at least part of the adhesive substance.

The manufacturing process may provide, during the assembly step, to vary a distribution of the adhesive substance of the bonding layer. In particular, the variation in the distribution of the adhesive substance may result in particular from a difference in the composition of the bonding layer or in the thickness of the bonding layer. It is thus possible to adapt the bonding layer to the particular application of the article produced. This adaptation can be made between different articles but also within the same article, depending on the desired behavior.

The adhesive substance may be a single-component adhesive sealant crosslinkable by condensation, preferably at ambient humidity and / or by thermal activation and / or by actinic activation, said adhesive sealant preferably being chosen from polyurethanes, modified silane polyurethanes, silicones , polysulfides, polyethers, silane modified polyethers and mixtures thereof.

The crosslinked adhesive substance can have an elongation at break of between 90% and 1500%.

The manufacturing process may include, during the forming step, shaping the article by pressing the laminate against a mold, preferably a bending mold having the shape of the article. The mold has one or more curvatures in one or more planes and especially in several directions, that is to say a more or less complex 3D shape. In particular, the mold may have recessed or raised areas.

The manufacturing process can also include a patterning step during which the structural layers are cut along the outline of the article. During the patronage stage:

- all or part of the structural layers can be cut before assembly to make the laminate according to the assembly step,

- the laminate produced during the assembly step can be cut, and / or

- the article obtained after the forming step can be cut.

Preferably, the patterning step is carried out before interposing the bonding layer between the bonding surfaces of the structure layers and making the laminate. These provisions make it possible to release the intrinsic stresses of the layers of structure before gluing and bending and thus allows greater deformations.

The joining layer may have a maximum thickness, measured perpendicular to the joining surfaces of the structure layers, of between 0.01 mm and 2 mm, preferably between 0.05 mm and 1.2 mm.

The laminate may have a maximum thickness, measured perpendicular to the joining surfaces of the structural layers, less than or equal to 30 cm, preferably 10 cm.

At least one of the structural layers is made of a material having an anisotropic mechanical behavior.

According to specific provisions, the invention aims to produce complex articles, in particular in three dimensions, of the type of those obtained by plastic molding but in noble, ecological and durable materials, including wood.

The manufacturing process can therefore be specially adapted for manufacturing an article consisting essentially of wood, that is to say at least 50% of wood, in particular at least 70%, preferably at least 80% Of wood. At least one of the structural layers is then a sheet of wood essentially consisting of wood, that is to say at least 50% of wood, in particular at least 70%, preferably at least 80% Of wood.

The wood sheet can have a maximum thickness measured perpendicular to the joining surface of between 0.1 mm and 5 mm.

According to a second aspect, the invention provides a laminate obtained at the end of the assembly step of the manufacturing process defined above, comprising a plurality of structural layers respectively having facing facing surfaces, and at least one bonding layer interposed between the bonding surfaces of the structural layers, at least one of the structural layers being a sheet made of an elastically deformable material, the bonding layer comprising a viscoelastic adhesive substance crosslinkable into elastomer and laid on at least part of the joining surfaces of the structural layers, the adhesive substance being non-crosslinked.

According to a third aspect, the invention provides a deformable article with shape memory, the article having at rest a shape and an outline, said article comprising a curved laminate, the laminate comprising a plurality of structural layers respectively having fixing surfaces facing, and at least one bonding layer interposed between the bonding surfaces of the structural layers, at least one of the structural layers being a sheet made of an elastically deformable material, the bonding layer comprising a viscoelastic adhesive substance crosslinkable in elastomer and extended over at least part of the joining surfaces of the structural layers, the adhesive substance being at least partly crosslinked.

Such an article can in particular be obtained by implementing the manufacturing process defined above.

Other objects and advantages of the invention will appear on reading the following description of a particular embodiment of the invention given by way of non-limiting example, the description being made with reference to the accompanying drawings in which :

- Figure 1 is a schematic perspective representation of an article consisting essentially of wood obtained by the implementation of an embodiment of the manufacturing method according to the invention, the article comprising a plurality of structural layers formed essentially of wood, and at least one bonding layer interposed between the structural layers, the bonding layer comprising a crosslinkable viscoelastic adhesive substance made of elastomer,

FIG. 2 is a schematic representation of a stage of patronage of the manufacturing process during which superimposed structural layers are cut according to an outline of the article,

- Figure 3 is a schematic representation of an assembly step of the manufacturing process during which the adhesive substance is deposited on at least one joining surface of each cut structure layer before crosslinking of the adhesive substance,

- Figure 4 is a schematic representation of the assembly step of the manufacturing process during which the adhesive substance is spread over the bonding surface before crosslinking of the adhesive substance to form the bonding layer,

- Figure 5 is a schematic representation of the assembly step of the manufacturing process during which a laminate is produced by interposing the bonding layers between the structural layers before crosslinking of the adhesive substance,

- Figure 6 is a schematic representation of a mold shaped according to a form of the article,

- Figure 7 is a schematic representation of a forming step of the manufacturing process during which the article is shaped by pressing the laminate on the mold so as to deform the structural layers of the laminate before crosslinking of the adhesive substance, the laminate being pressed onto the mold by a vacuum cover subjected to a vacuum,

- Figure 8 is a schematic representation of a variant of the forming step of the manufacturing process of Figure 7 during which the laminate is pressed on the mold by a counter-mold.

In the figures, the same references designate identical or analogous elements.

FIG. 1 schematically represents an embodiment of an article 1 obtained from a laminate 5 comprising several layers of structure 6 superimposed between which bonding layers 7 are interposed. In the embodiment shown, without being limited thereto, article 1 is the frame 2 of a protective mask for the eyes of a user during the practice of mountain activities in winter. The frame 2 comprises a frame 3 delimiting a recess 4.

In the embodiment shown, without being limited thereto, the laminate 5 consists essentially of wood, that is to say of at least 50% of wood, and in particular of at least 70% of wood, of preferably at least 80% wood. One or more of the structural layers 6 are sheets of wood consisting essentially of wood, that is to say of at least 50% wood, and in particular at least 70% wood, preferably at least 80% wood. The wood used for the wood sheets can be of any suitable type, particularly in terms of species or provenance (natural, recycled, scrap recovery, etc.). Depending on the properties and the esthetics sought, the structural layers 6 may also include sheets of other kinds than wood and in particular sheets of metal, plastic material, composite material, leather or the like.

Each of the structural layers 6 has opposite joining surfaces having a length L and a width 1 in first DI and second D2 directions perpendicular to each other, and a thickness e measured in a third direction D3 perpendicular to the first DI and second D2 directions , between the two joining surfaces. Each structural layer 6 has a thickness e reduced with respect to the length L and the width 1. Each sheet of wood can in particular have a thickness of between 0.1 mm and 5 mm.

Each of the securing layers 7 comprises an adhesive substance 8 made of crosslinkable or polymerizable elastomer. In particular, the adhesive substance 8 can have an elongation at break of between 90% and 1500%. The adhesive substance has a crosslinkable viscoelastic behavior. For example, the adhesive substance 8 is constituted by a single-component adhesive sealant crosslinkable by condensation, preferably at ambient humidity and / or by thermal activation and / or by actinic activation. The adhesive sealant can be chosen from polyurethanes, modified silane polyurethanes, silicones, polysulphides, polyethers, modified silane polyethers and mixtures thereof.

The adhesive sealant may have, in the non-crosslinked state, a viscosity suitable for application in a layer of thickness that is substantially constant or not, for example a dynamic viscosity at 20 ° C. of between 10 ' ² Pa.s and 10 ³ Pa.s, preferably between 10 Pa.s and 10 ² Pa.s.

By interposing such an adhesive substance 8 between the joining surfaces of the structural layers 6, the article 1 can be shaped so as to have one or more curvatures around one or more axes while being deformable with shape memory. . Item 1 may in particular have a three-dimensional shape such as that of the protective mask (ski mask) shown. We thus obtain an article having a certain shape in 3D and able to deform elastically and return to this shape in 3D after elastic deformation This adhesive substance 8 is viscous which allows to adapt the concentration and / or the thickness within of the same article or from one article to another in order to obtain the desired behavior.

Article 1 is obtained by implementing a manufacturing process, a particular non-limiting embodiment of which is described in relation to FIGS. 2 to 8.

Plates in which the structure layers 6 are formed are stored. They include wooden plates in which the wooden sheets are formed and possibly plates of any other kind suitable for the production of the article.

1. They include, for example, rectangular wooden plates 3500 mm long, 300 mm wide and 0.6 mm thick.

FIG. 2 illustrates a patterning step during which the structural layers 6 are cut along an outline of the article 1. In the embodiment shown, the plates 10 pre-debited into plates 11 of reduced dimensions, for example 240 mm in length and 110 mm in width, are superimposed on a height h, for example of 60 mm. The structural layers 6 are then cut along an outside contour of the frame 3 of the frame 2 and an inside outline of the recess 4 of the frame

2. The cutting of the structural layers 6 can be carried out in any suitable manner and in particular by means of a laser cutter to make a precise cut, of a cookie cutter for a series cut and / or a cutter for a linear cut. During the patronage stage, the wood sheets can be arranged in a desired orientation of the wood sheets in article 1, in particular 0 °, 90 °, + 45 ° or -45 °. This makes it possible to obtain a particular character of rigidity or bending, orthotropic or pseudo isotropic.

The structural layers 6 can be treated. For example, the wood sheets can be dyed in particular in an aqueous tint bath. According to an advantageous embodiment, the wood sheets can undergo a surface treatment in order to facilitate bonding.

FIGS. 3 to 5 represent a step of assembling the manufacturing process consisting in making the laminate 5 by interposing the securing layers 7 between the structural layers 6. In particular, in FIG. 3, the adhesive substance 8 is deposited, before crosslinking of the adhesive substance 8, by any suitable means, such as a pneumatic gun 16, on at least one of the joining surfaces of each structural layer 6. In FIG. 4, the adhesive substance 8 is spread out, for example by means of a manual grader 17, on the joining surface before crosslinking of the adhesive substance 8 to form the joining layer 7. As a variant, the deposition and spreading of the adhesive substance 8 can be obtained by automated means. The joining layer 7 may have a maximum thickness, measured perpendicular to the joining surfaces of the structure layers, of between 0.01 mm and 2 mm, preferably between 0.05 mm and 1.2 mm. In FIG. 5, the structure layers 6 are stacked with the connection surface of one of the structure layers 6 facing the connection surface of the adjacent structure layer 6. The stacking is carried out before crosslinking of the adhesive substance 8, where appropriate following a sequence determined as to the orientation of the sheets of wood.

At the end of this step, the laminate 5 comprising superposed structure layers 6 and bonding layers 7 interposed between the bonding surfaces, with the non-crosslinked adhesive substance 8, is obtained. The laminate 5 may have a thickness E measured perpendicular to the surfaces for joining the structural layers 6 less than 30 cm, preferably less than 10 cm, for example 3 cm.

Before crosslinking of the adhesive substance 8, the article 5 is shaped during a forming step by bending the laminate 5 so as to deform the structural layers 6. The laminate 5 then has one or more curvatures according to different directions in one or more distinct and intersecting planes. In the embodiment shown, a deformation is applied to keep the wood sheets in the elastic range. Complementarily or alternatively, depending on the materials from which the structure layers 6 are made, the applied deformation may be elastic or plastic.

In particular, during this step consisting in shaping the article 1, the laminate 5 is pressed on a mold 20, shown in FIG. 6, shaped according to a shape of the article 1. The mold 20 can be produced in any suitable material, in particular in medium density fiberboard (MDF according to the English name: medium density fiberboard), in composite material, plaster, aluminum or other, for example by 3D printing or strato-design. In the embodiment shown, the mold 20 is a positive mold having the overall shape of the top of a face on which the frame 2 of the mask will be applied.

The laminate 5 is placed on the mold 20 and positioned using rods 21, the length of which corresponds substantially, for example to within 10%, to the thickness E of the laminate 5 to avoid impeding or reducing the pressure used. on the laminate 5 to deform the layers of structure 6. Alternatively, the laminate 5 could be positioned and held in place by any suitable means. In particular, a hollow imprint materialized in dashed lines in FIG. 6 could be provided in addition to or in replacement of the rods or any other member for holding the laminate.

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In FIG. 7, in order to bend the laminate 5, the laminate 5 is pressed on the bending mold 20 using a vacuum press implementing a vacuum membrane 22, for example made of silicone or polyurethane with 600% elongation, subject to depression. In the embodiment shown, the bending is obtained at a temperature between 10 ° C and 70 ° C with a pressure of - 0.9 bar applied for 2 h to 6 h for an adhesive substance 8 polyurethane and 5 minutes to 20 minutes for an adhesive substance 8 of hotmelt type.

In a variant shown in FIG. 8, to achieve the bending of the laminate 5, the laminate 5 can be pressed on the mold 20 by a counter mold 25.

In addition, in other embodiments, the shaping of the article 1 could be obtained by bending the laminate 5 by pressing it in a negative mold.

It is only after crosslinking of the adhesive substance 8 that it can maintain the curvatures of the laminate 5 resulting from its molding and that the shaped article 1 can be recovered in particular to undergo machining steps. and finishing.

The present process described is therefore much simpler and much less expensive than the usual known processes since it requires a single mold, a membrane vacuum press and low temperatures and manufacturing pressure. The crosslinkable viscoelastic adhesive substance made of elastomer used is little or not subject to creep and allows relative sliding of the structure layers and thus shearing in the laminate, which results in residual flexibility while allowing 3D shaping. Its implementation makes it possible to bond at low pressure and with controlled thickness and to better manage the mechanical properties, in particular of flexibility and elasticity, of the laminate and of the resulting article. The mechanical properties of the laminate can be modulated either locally or throughout the laminate

The method is applicable to the production of other shaped articles as well as in a plate seeking the same flexibility and / or mechanical characteristics, and for example diving fins, furniture, packaging, bodywork, objects art and decoration, piece of art, shell, sports accessories, design objects, glasses, container, play, interior and exterior layout panels, book cover, accessory of protection and overall any article that can be designed with a laminate shaped or plate.

It is, moreover, specially adapted to the small series and personalization of products in 3D form based on wood as described above, elastically deformable, that is to say able to return to their original form (for example , a shape given by a mold) after deformation under a determined force (not exceeding their elastic limit).

Claims (10)

1. Method for manufacturing an article (1) deformable with shape memory, the article (1) having at rest a shape and an outline, the manufacturing method being characterized in that it comprises: - an assembly step during which a laminate (5) is produced, the laminate comprising a plurality of structural layers (6) having respectively facing facing surfaces, and at least one interlocking layer (7) interposed between the fastening surfaces of the structural layers (6), the structural layers (6) being made of an elastically deformable material, the fastening layer (7) comprising an adhesive substance (8) viscoel asti that crosslinkable in elastomer and extended over at least part of the joining surfaces of the structural layers (6), - A forming step during which the laminate (5) is bent to obtain the shape of the article (1) and the adhesive substance (8) of the bonding layer (7) undergoes crosslinking. 2. Method according to claim 1, providing, during the assembly step, to vary a distribution of the adhesive substance (8) of the bonding layer (7). 3. The manufacturing method according to claim 1 or 2, wherein the adhesive substance (8) is a single-component adhesive sealant crosslinkable by condensation, preferably at ambient humidity and / or by thermal activation and / or by actinic activation, said adhesive sealant preferably being chosen from polyurethanes, modified silane polyurethanes, silicones, polysulphides, polyethers, modified silane polyethers and mixtures thereof. 4. The manufacturing method according to any one of claims 1 to 3, wherein the crosslinked adhesive substance (8) has an elongation at break of between 90% and 1500%. 5. Manufacturing method according to any one of claims 1 to 4, providing, during the forming step, to shape the article (1) by pressing the laminate (5) against a mold, preferably a mold bending device (20) having the shape of the article (1). 6. Manufacturing process according to any one of claims 1 to 5, further comprising a patterning step during which the structural layers (6) are cut according to the outline of the article (1). 7. The manufacturing method according to any one of claims 1 to 6, wherein at least one of the structural layers (6) consists of a material having an anisotropic mechanical behavior. 8. The manufacturing method according to any of claims 1 to 7, specially adapted for manufacturing an article (1) consisting essentially of wood, in which at least one of the structural layers (6) is a sheet of wood consisting essentially of wood. 9. Laminate (5) obtained at the end of the assembly step of the manufacturing process according to any one of claims 1 to 8, comprising a plurality of structural layers (6) respectively having facing solidaf sation surfaces , and at least one solidification layer (7) interposed between the solidification surfaces of the structural layers (6), at least one of the structural layers (6) being a sheet made of an elastically deformable material, the layer solidaf sation (7) comprising an adhesive substance (8) viscoelastic crosslinkable elastomer and extended on at least a portion of the joining surfaces of the structural layers (6), the adhesive substance (8) being non-crosslinked. 10. Deformable article with shape memory, the article (1) having at rest a shape and an outline, said article (1) comprising a curved laminate (5), the laminate (5) comprising a plurality of structural layers ( 6) having respectively facing facing surfaces, and at least one solidifying layer (7) interposed between the solidating surfaces of the structural layers (6), at least one of the structural layers (6) being a sheet made of an elastically deformable material, the solidification layer (7) comprising an adhesive substance (8) viscoelastic crosslinkable in elastomer and extended over at least part of the surfaces for joining the structural layers (6), the adhesive substance ( 8) being at least partially crosslinked.