CH713313A2 - Dressing room with decor for a watch or jewel and its manufacturing process. - Google Patents

Abstract

The present invention relates to a method of manufacturing a dressing part for a watch or jewel, in particular a bracelet (5), comprising the steps of: providing a substrate (1) comprising a first face opposed to a second face, coating by coextrusion on the first face and on the second face of said substrate (1) with respectively first and second strips (2) of synthetic material; the first band (2) forming on the first face a transparent or translucent layer for maintaining all or part of the visible substrate (1).

Description

Description

OBJECT OF THE INVENTION The present invention relates to the field of watchmaking and jewelry. More particularly, it relates to a method of coating by co-extrusion on a substrate for manufacturing, inter alia, bracelets.

TECHNOLOGICAL BACKGROUND AND STATE OF THE ART [0002] Plastic bracelets presenting different colors, decorations or incorporating particular visual effects are very popular with customers. This type of bracelet can be manufactured by molding, overmolding or bi-injection of plastic materials of different colors. These are multi-step batch manufacturing processes, making them unsuitable for inexpensive mass industrial production.

In the past, it has been proposed to make bracelets by an extrusion process which is a less expensive process. The manufacture of bracelets by extrusion has generally been limited to the manufacture of bracelets of simple shape, single-colored and made of the same material as described in document FR 2 121 864. Lately, it has been proposed in application EP 16 150 493 co-extrude materials of different colors or properties to form bracelets with more elaborate geometries and properties.

However, these methods do not allow complex patterns to be produced which imply particular geometries and very high precision as in the case of landscapes, figurines, messages, etc. It is also difficult to integrate materials other than plastics which could lead to an original aesthetic effect.

In general, bracelets with complex patterns are produced by digital printing on single-color substrates produced by molding. Digital printing provides access to a wide variety of designs. However, the process has several drawbacks: the pattern is only on the surface, so it is sensitive to mechanical wear. This means that over time, the pattern fades. This wear is generally irregular, which leads to an aesthetic appearance of the bracelet that is very quickly unsatisfactory. The pattern is also sensitive to UV and chemical attack. The bracelets produced by this type of process therefore have patterns that change over time with the appearance of unwanted and unaesthetic effects. Document FR 2 639 870 solves this problem by proposing a bracelet formed with a thermoplastic body, a printed film and a transparent protective layer. However, the manufacturing process proposed in this document is an injection molding process II follows from the problems of positioning and holding the printed film in place in the mold. In addition, the process is long (printing and cutting the printed film, positioning the film in the mold, molding, and making the transparent protective layer) and requires several manual operations. This prevents high rates.

Another disadvantage of printing on the surface of the bracelet is the lack of adhesion of digital printing inks on plastic bracelets of the silicone type which have low surface energies. In addition, a change in the basic plastic formulation of the bracelet often involves readjusting the ink formulation.

SUMMARY OF THE INVENTION The object of the present invention is to manufacture coverings and more particularly bracelets with complex patterns using a simple and inexpensive process which can be compatible with production rates. high production. The present invention more specifically aims to integrate a decoration into the dressing room, without any problem of positioning or adhesion of the ink in the case of a printed decoration. The present invention also aims to develop a manufacturing process guaranteeing the stability over time of the printed decoration.

To this end, the invention relates to a method of manufacturing a covering piece for a watch or piece of jewelry, in particular a bracelet, comprising the steps of:

- provision of a substrate comprising a first face opposite to a second face, coating by co-extrusion on the first face and on the second face of said substrate with respectively a first and a second strip of synthetic material; the first strip forming on the first face a transparent or translucent layer making it possible to maintain all or part of the visible substrate.

According to an advantageous embodiment of the manufacturing method of the invention, a step of printing and / or etching a decoration on the first face of the substrate is provided before the step of coating by co-extrusion of the first and second faces of the substrate and preferably a plurality of distinct decorations are printed and / or engraved one after the other on the first face of the substrate.

According to a preferred variant, a step of making available 2D or 3D files comprising personalized data relating to the printing or engraving of each decoration is provided before the printing step.

Other particular embodiments are included in the dependent claims.

CH 713 313 A2

BRIEF DESCRIPTION OF THE FIGURES The characteristics and advantages of the present invention will appear on reading the detailed description below referring to the following figures.

Fig. 1 shows a schematic view of the extruders upstream of the co-extrusion die for carrying out the process according to the invention.

Fig. 2 illustrates the process of printing sequences of different patterns on a blank strip. The strip thus decorated is used as a substrate in the co-extrusion coating process according to the invention.

Fig. 3 shows according to the invention a schematic view of the multilayer extrudate from the co-extrusion die and this same extrudate after cutting and stamping. According to this variant, the bracelet is co-extruded in the longitudinal direction of the bracelet.

In fig. 4, another variant is presented where the bracelet is co-extruded in the transverse direction of the bracelet.

The extrudate after cutting is also shown. It has at its lateral ends hollow tubular structures useful for the subsequent fixing of the bracelet to the case.

Fig. 5 shows a partial perspective view of a watch with a bracelet obtained according to the method of the invention and fixed to the case with a NATO type construction.

Fig. 6 shows a perspective view of a watch with a bracelet made according to the co-extrusion method of the invention. The upper band of the bracelet has raised areas separated by recesses. Although not illustrated, the upper strip is transparent or translucent to visualize the decoration of the central strip.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for manufacturing cladding parts for watchmaking or jewelry by coating a substrate by co-extrusion, commonly co-extrusion coating in English. By covering pieces is understood in particular the bracelet, the watch case and its constituent elements, the bezel or even the dial. This process is more particularly described here for the manufacture of bracelets. The method consists in coating a substrate having a complex decoration and / or a texture with strips of synthetic materials. Fig. 1 schematically illustrates the process with the reel of decorative strip forming the substrate 1 coated respectively on each side by co-extrusion of a synthetic material 2. According to the invention, the coating facing the decoration is at least partly transparent or translucent in order to be able to visualize the patterns of the decoration.

The decorative strip is formed from any flexible substrate capable of withstanding high temperatures in the order of 200 ° C for a few seconds. It typically has a thickness between 50 μm and 2 mm and preferably between 100 and 500 μm.

The pattern can be uniform all along the strip. For example, the decorative strip may be a natural or synthetic textile strip (non-woven, unidirectional, woven, braided, knitted) made in particular of the following materials: linen, cotton, hemp, wool, polyester, polyamide-polyurethane. The decorative strip may also be a strip of photo paper, a metal sheet, an adhesive strip incorporating mineral particles such as sand, organic particles such as wood fibers, vegetable materials or metallic particles such as gold leaf. The decorative strip may also be a strip of elastomeric thermoplastic such as: a strip of TPU, TPI, TPE-0 (thermoplastic olefins), of TPE-S - (styrenic thermoplastics), of TPE-E (thermoplastic copolyester), of TPE -A (thermoplastic copolyamide) or in TPE-V and TPSi-V (combination of thermoplastic and crosslinked silicone). The decorative strip can also be a PVC, PET, in certain varieties of polycarbonate or PC, natural or synthetic rubber. The strip can be used raw and, in this case, the decor is provided by the material itself with its natural fiber appearance, its metallic luster, etc. The strip can also be decorated by conventional printing methods such as, for example, pad printing, screen printing, offset, flexography, digital printing. In particular, printing on a substrate can make it possible to integrate into the decor colored pigments, compounds having fluorescent, phosphorescent, thermochromic or photochromic properties. The strip can also be decorated by on-line calendering etching processes. From an industrial point of view, this process is well suited to the manufacture of collections of bracelets. Within the same collection, the bracelets have an identical design and the production of a new collection involves only the change of the reel of decorative band.

According to a variant of the invention, the pattern is printed on demand on the virgin strip substrate. Several sequences of different patterns can thus be printed and / or engraved consecutively on the same strip 1 as illustrated in FIG. 2. Printing is preferably carried out by digital printing to allow greater flexibility. In this case, the bands of thermoplastic elastomer (TPE-O, TPU, TPI, TPE-S, TPSi-v, TPE-v), of rubber, of PET, synthetic or natural textile bands, (in particular synthetic leathers ) etc. are particularly

CH 713 313 A2 adapted. From an industrial point of view, this mass process is particularly suitable for the manufacture of personalized bracelets. The customer chooses his design (drawing, personal photo, etc.) and, possibly the type of substrate, online or in store, his design preferably in the form of a digital file is processed to adapt to the dimensions of the substrate, then the 2D or 3D pattern is printed by digital printing on a portion of blank substrate strip of length corresponding to the width or the length of a bracelet strand. Then, once the decorative strip is fully printed with the different sequences of patterns chosen by customers, it is coated with the two strips of synthetic material. The multilayer extrudate thus formed is cut using a water jet, a laser, a digital knife (for example the machines offered by the manufacturer Zünd) or by stamping to yield a personalized bracelet.

The plastic wrapping strips according to the invention are intended to protect the decorative strip from external aggressions and to provide a particular aesthetic and / or visual appearance, for example the plastic wrapping strips can be arranged to present a magnifying glass effect or another analogous optical effect. There is an interior coating strip intended to be in contact with the skin and an exterior coating strip positioned on the opposite face of the substrate. Typically, these strips have a thickness of between 100 μm and 2 mm and, preferably, between 100 μm and 1 mm.

The outer coating plastic strip is at least partially transparent or translucent with a transmission index greater than 60% according to standard ASTM D-1003 so as to reveal the pattern of the decorative strip. Several configurations can be envisaged. In a first variant, the outer strip is entirely transparent or translucent and therefore lets the pattern appear over the entire surface. In a second variant, the outer wrapping strip is obtained by co-extrusion of mixtures of materials of different colors or refractive indices, at least one of the mixtures being transparent to reveal the pattern of the decorative strip. It is thus possible, for example, to produce across the width of the extrudate different colored lines while maintaining a transparent or translucent zone. This configuration provides different depth effects between the edges and the center of the bracelet.

The interior wrapping plastic band is chosen to provide comfort to the client. It has a hardness between 55 and 90 shore A and may contain additives to improve comfort. For example, it may contain ceramics of the hexagonal boron nitride type to dissipate the heat energy and reduce sweating. It can also contain textile fibers having a capillary effect in order to evacuate sweat, or aluminum salts to limit sweating. It may also contain antibacterial agents such as silver particles or zinc pyrithione for an anti-odor effect. As with the outer band, it can be obtained by co-extrusion of plastic mixtures of different colors or of different refractive indices to provide different optical effects between the edges and the center of the bracelet. Likewise, the present invention does not exclude that the inner strip is also at least partially transparent or translucent.

According to the invention, the synthetic materials used during coating by co-extrusion are mixtures comprising at least one elastomer. The preferred elastomers are thermoplastic elastomers, silicones, rubbers and fluorinated elastomers.

More specifically, for the outer band, the elastomers are preferably chosen from the following list:

- TPE-0 - Thermoplastic olefins

- TPE-S - More particularly the SBS, SEBS or SEPS styrenic compounds

- TPE-E - Composed of copolyester

- TPE-U - Thermoplastic polyurethane

- TPE-A - Thermoplastic polyamide

- Ionomer resins

- Silicones and preferably MVQs (methylvinylsilicones)

- Fluorinated elastomers: FKM.

More specifically, for the inner strip, the elastomers are preferably chosen from the following list:

- TPE-0 - Thermoplastic olefins

- TPE-S - More particularly the SBS, SEBS or SEPS styrenic compounds

- TPE-V - More particularly PP / EPDM or TPSiV compounds (combination of thermoplastic and crosslinked silicone)

- TPE-E - Composed of thermoplastic copolyester

- TPE-U - Thermoplastic polyurethane

- TPE-A - thermoplastic coPolyamide

- Ionomer resins

- Silicones and preferably MVQs (methylvinylsilicones)

- Fluorinated elastomers: FKM.

Preferably, the synthetic materials for the inner band and the outer band are chemically compatible and preferably the same to ensure good cohesion of the bracelet.

Depending on the elastomer selected for its specific properties, the mixture may be supplemented with the various fillers and additives desired to improve customer comfort.

CH 713 313 A2 The coating method by co-extrusion can consist in manufacturing a multilayer extrudate 3 having a width corresponding to the width of the bracelet as shown in FIG. 3. Advantageously, the substrate 1 has a width less than that of the lower and upper strips 2 so as to be coated around the entire periphery of its cross section with the synthetic strips. The co-extrusion coating process can also consist in manufacturing a multilayer extrudate 3 having a width corresponding to the length of one strand or two strands of the bracelet as shown in FIG. 4. Similarly, the cross section of the substrate is completely covered by the synthetic material. According to the embodiment of FIG. 3, the shape of the bracelet 5 and the desired holes 6 are obtained by stamping, laser cutting, digital knife or water jet. The multilayer extrudate obtained after co-extrusion can be in one piece and attached to the watch case 8 using loops 7 disposed on each side of the watch case, it is a so-called NATO construction illustrated in fig. 5. According to the embodiment of FIG. 4, in order to facilitate the subsequent assembly of the strap to the watch case, it is advantageous to manufacture a multilayer extrudate 3 comprising at the lateral ends a hollow tubular structure 9 projecting intended to receive a bar allowing respectively the attachment to a box of watch with horns and a buckle, the width required for the bracelet being obtained beforehand by laser cutting, digital knife, water jet or stamping. It is also conceivable to manufacture a multilayer extrudate integrating over its width the profile of the case framed by the strands of the bracelet, the recess of the case being able to be produced subsequently by stamping.

It will further be specified that the co-extrusion die may have an original profile making it possible to extrude encapsulating strips with projecting zones or, more generally, having a particular relief. Fig. 6 illustrates for example the profile which could be obtained for the outer band of the bracelet. It is also possible without departing from the scope of the invention to take advantage of the other advantages of the extrusion process, such as combining several materials in order to locally modify the mechanical properties of the bracelet, in particular at the level of the fasteners, for example.

The bracelets thus produced by co-extrusion have many advantages.

The method according to the invention is an inexpensive mass method which makes it possible to obtain personalized bracelets with a design chosen by the customer, or even a unique bracelet. One thus differs from the molding processes piece by piece little adapted for mass production with high rates.

Very different designs can be obtained without modification of the industrial line.

The bracelets have a particular aesthetic with a depth effect and a three-dimensional effect generated by the thick and transparent layer of synthetic material.

The complex pattern is located inside the bracelet. It is therefore protected from external aggressions (mechanical wear, chemical aggressions, UV, ...) by the synthetic band. The pattern is printed on a flat substrate and not on a three-dimensional bracelet, which also greatly simplifies the printing process.

Unlike the injection molding process, the process according to the invention makes it possible to precisely position the decorative strip within the synthetic material.

The nature of the decorative strip can be chosen to ensure good adhesion of the ink regardless of the basic formulation of the bracelet.

In addition, the integrity of the bracelet is ensured by the adhesion between the upper strip and the lower strip without having to worry about the adhesion properties between the decorative strip and the wrapping strips. These characteristics make it possible to integrate any type of support within the dressing part, including textiles.

Legend [1] (1) Substrate, also called decorative strip (2) Outer strip and inner strip (3) Extrudate (4) Printer (5) Bracelet (6) Hole (7) Loop (8) Housing (9) Tubular structure dig

CH 713 313 A2 (10) Watch

Claims (15)

claims 1. Method for manufacturing a piece of clothing for a watch or jewelry, in particular a bracelet (5), comprising the steps of: - provision of a substrate (1) comprising a first face opposite to a second face, - Co-extrusion coating on the first face and on the second face of said substrate (1) with respectively a first and a second strip (2) of synthetic material; the first strip (2) forming on the first face a transparent or translucent layer making it possible to keep all or part of the substrate (1) visible. 2. Manufacturing method according to claim 1, characterized in that it comprises, before the step of coating by co-extrusion, a step of printing and / or etching a decoration on the first face of the substrate (1 ). 3. Method according to claim 2, characterized in that a plurality of distinct decorations are printed and / or engraved one after the other on the first face of the substrate (1). 4. The manufacturing method according to claim 3, characterized in that it comprises before printing a step of making available 2D or 3D files comprising the personalized data relating to the printing or engraving of each decoration. 5. Method according to any one of the preceding claims, characterized in that the substrate (1) is formed from a natural or synthetic textile strip, from a strip of photo paper, from a metallic strip, from a strip thermoplastic elastomer, a rubber band, or an adhesive band. 6. Method according to any one of the preceding claims, characterized in that the substrate (1) comprises a material chosen from the list consisting of linen, cotton, hemp, wool, synthetic leather, polyester, polyamide, polyurethane, olefin thermoplastic (TPE-O), polyimide thermoplastic (TPI) urethane thermoplastic (TPU), styrenic (TPE-S) or copolyester (TPE-E) or polyamide copolyester (TPE-A), rubber, polyvinyl chloride, PET. 7. Method according to claim 5, characterized in that the adhesive strip comprises mineral particles, organic particles or metallic particles. 8. Method according to any one of claims 2 to 7, characterized in that the printing makes it possible to integrate into the decor colored pigments, luminescent compounds, thermochromic compounds, photochromic compounds or a mixture of these . 9. Method according to any one of the preceding claims, characterized in that the substrate (1) has a width less than that of the first and second strips (2) so as to be coated by the latter during the coating step by co-extrusion. 10. Method according to any one of the preceding claims, characterized in that the first strip and / or the second strip (2) made of synthetic material are obtained by co-extrusion of several mixtures of synthetic materials distinguished by their colors and / or their refractive indices and / or their mechanical properties. 11. Method according to any one of the preceding claims, characterized in that the synthetic materials of the first and of the second strips (2) are chosen from thermoplastic elastomers, silicones, rubbers and fluorinated elastomers. 12. Method according to any one of the preceding claims, characterized in that the synthetic material of the second strip (2) comprises a filler improving the comfort of the covering piece. 13. Method according to any one of the preceding claims, characterized in that the extrudate (3) coming from the coating by co-extrusion has a width corresponding to the width of the bracelet (5) or to the length of one or two bracelet strands (5). 14. Dressing piece for watchmaking or jewelry, in particular bracelet (5), comprising a flat substrate (1) coated around the entire periphery of its cross section with one or more synthetic materials, the synthetic material or materials forming at least partially a transparent or translucent coating. 15. Dressing piece according to claim 14, characterized in that the substrate (1) comprises on a face opposite the transparent or translucent coating a printed or engraved decoration. CH 713 313 A2 CH 713 313 A2