IT202000008161A1 - Process of making metal accessories, and metal accessories made in this way. - Google Patents

Description

? Process of making metal accessories, and metal accessories so? made.?

DESCRIPTION

The present invention relates to a process for manufacturing metal accessories, for the fashion, clothing, footwear, leather goods and similar sectors, and metal accessories as such. made.

How ? known, most of the products in the fashion sector (leather goods, clothing, footwear, etc.) are based on passing trends and, as such, have a very short life cycle; likewise, these are products whose purchase? widely diffused in industrialized economies. As a consequence, the sector in question determines a high accumulation of waste which, moreover, due to the materials commonly used for their production, are often not biodegradable.

Pi? in general, the waste of materials, the difficulty? to ensure the recycling of a mass so? large amount of potential waste and the intensive use of natural resources in the production process make fashion one of the sectors with the greatest environmental impact in the world.

The great attention to eco-sustainability? and the respect for the environment observed in recent years, has therefore inevitably also involved the fashion sector, focusing on critical issues? illustrated above. The sector operators have developed a greater sensitivity? towards the search for captivating but at the same time sustainable and "clean" products, without forgetting the right quality-price ratio, traceability. of the supply chain and the quality? intrinsic of the product (the latter parameters, however, of extreme interest for an increasingly evolved and attentive final clientele).

In this context,? It is possible to notice how the manufacturing companies are looking for new solutions for the production of various types of accessories that complete the various products: buckles, chains, buttons, components for leather goods and footwear and other accessories have so far been typically made of brass, zamak or steel (or even in polymeric materials such as ABS or methacrylate) and then subjected to galvanic finishing cycles, to cover them with external layers that often include gold, palladium or other precious materials.

Accessories of this type, with a low life cycle, are evidently very widespread and therefore contribute significantly to the amount of waste that is difficult to dispose of, referred to in the previous paragraphs.

Another problem is associated with this problem, however connected to the general theme outlined above: the production techniques (galvanic cycles for example) of many of these accessories often involve the use of toxic or allergenic substances, such as nickel, which can find yourself in the final product (with negative consequences for consumers) or in any case cause difficulties? for operators and / or the management of the process phases (the treatment and disposal of fumes for example).

Pi? in general, yes? also? found how lately the manufacturing companies are looking for production techniques aimed at the realization of accessories that, while maintaining (or even increasing) the properties? mechanical and the resistance to wear and / or corrosion that distinguish known accessories, require a lower use of precious materials (whose cost is constantly and significantly increasing).

The main aim of the present invention? that of solving the above problems by proposing a process for the production of accessories for the fashion sector with a low environmental impact.

Within the scope of this aim, an object of the invention? to propose a process that allows to obtain accessories for the fashion world with performance and properties? similar if not superior to those of known solutions, but in an eco-sustainable way and without resorting to toxic or allergenic substances.

Another object of the invention? that of proposing a procedure that allows to create easily recyclable and non-polluting accessories, however able to guarantee adequate properties? mechanical and resistance to wear, abrasion and / or corrosion, even without the use of gold, palladium or other precious materials.

Another object of the invention? to create eco-sustainable accessories, easily recyclable and which ensure high reliability? of operation.

Another object of the invention? that of proposing a process that adopts an alternative technical and structural architecture to those of the known type of process.

Not the least object of the invention? to propose a procedure that is easily feasible starting from commonly available elements and materials? on the market.

Yet another object of the invention? that of proposing a procedure that can be implemented in a simple way and with low costs.

This aim and these and other objects which will become clearer in the following are achieved by a method according to claim 1 and by an accessory according to claim 10.

Further characteristics and advantages of the invention will become clearer from the description of a preferred but not exclusive embodiment of the method according to the invention, illustrated by way of non-limiting example, in the accompanying drawings, in which:

figure 1? a block diagram illustrating the method according to the invention;

Figure 2 illustrates an accessory made by means of the method according to the invention, in an axonometric view and with some portions removed to show its composition;

figure 3? a detail of a cross section of the accessory of figure 2, which shows its composition.

With particular reference to the aforementioned figures,? generally indicated with the reference number 1, a process for manufacturing metal accessories 10 for the fashion, clothing, footwear, leather goods and similar sectors.

In other words, it is specified that the procedure 1? aimed at the realization of accessories 10 (or also of other equivalent products) intended for the various (sub) sectors that can be included in the pi? wide fashion sector (high fashion in particular, but not only), and therefore, in particular, clothing, footwear and leather goods (and the like).

With reference therefore to this application, the procedure 1 allows to produce buckles (such as that of figure 2), studs, hinges, chains, buttons, rings, zip pullers, heels, multi-component systems for closures, other components or accessories 10 (with smaller shapes ? disparate and complex) for the fashion sector, being able to do so? replace the known productions (made of metallic materials or not) keeping unchanged (or increasing) the performances and the quality? aesthetic, but with easy possibilities? of disposal and recycling, and in general with a much more? low environmental impact, how will it be? better clarified later.

According to the invention, the method 1 consists first of all, in a step a., In the molding (at high temperature) of a cast 11 made of magnesium alloy. By way of example and not limiting, the possibility is mentioned? that the casting 11 is made of magnesium and aluminum and / or zinc (and / or other metals) alloy.

How ? known, magnesium (the lightest of the structural metals) does not exist in nature in the free state due to its high reactivity, but is found combined with other elements. Numerous properties of it are known and appreciated, such as high lightness, capacity? vibration damping, ductility, conductivity, specific resistance and electromagnetic shielding. Thanks to the method 1 according to the invention, these properties? can therefore be given to the accessories 10 cos? realized, together with the ease? recycling and disposal that magnesium alloys present. In fact, the energy required for the recycling process of magnesium alloys (and therefore of accessories 10),? less than that required by other metals and? equal to 4% of that necessary for the production of the? virgin? alloy, therefore? a material whose use also allows to reduce the environmental impact.

At the same time, the die casting and the other steps of the process 1 according to the invention allow to cancel or contain the drawbacks traditionally associated with magnesium, such as the high flammability, the limited workability. hot or poor corrosion resistance.

Die casting (at high temperature), also known as the term "tixostampaggio",? a process of injection molding of magnesium alloys in a semi-solid state (form not risky for handling) thanks to special machinery designed to work at high pressures in an inert atmosphere of argon as an antioxidant cover gas. For the implementation of phase a., The chosen alloy can? be loaded in the form of granules at room temperature into a hopper mounted directly on a cylinder with a screw. The rotation of the latter doses the material along the entire length of the cylinder, brought to temperature by electric heating bands, and crushes the dendrites in the liquid fraction making it pass to a thixotropic semi-solid state, that is? capable of becoming liquid due to mechanical agitation. The alloy in the thixotropic state is injected with laminar flow into the heated mold and allowed to solidify.

The part extracted after solidification (the casting 11) will have? an equi-axial microstructure and no more? dendritic with consequent improvement of the properties? mechanical.

The advantages of this process are manifold and consist in the high process control, constancy of the parts produced, almost total minimization of porosity, molding of complex parts with consequent reduction and / or elimination of secondary operations such as welding, as well as? obviously the improvement of the production environment from an environmental and safety point of view. Also with this process? It is possible to use different customized alloys as feed according to the required specifications, simply by adjusting the temperature and feeding to the hopper.

The choice of the mold? preferably made in such a way that the casting 11 obtained at the end of step a. it has a shape substantially compatible with the accessory 10 to be made.

It also goes? specified that phase a. provides the possibility? to make any number of castings 11 with the same molding cycle (using multi-cavity molds).

Once the casting 11 has been obtained, the process 1 according to the invention consists, in step b., In covering it at least partially (and preferably completely) with a first coating layer 12 by means of at least a first spray painting treatment, using a paint catalyzed primary (which in the terminology of the sector can also be called "primer basecoat") based on at least one epoxy resin and an epoxyacrylic copolymer (typically of a mixed aliphatic / aromatic nature).

Pi? precisely, this resin can? be transparent or in black / colored variant.

In particular, in an embodiment of the procedure 1 of significant practical interest, step b. at the end of the first painting treatment and after observing a further dust-free period of between 10 minutes and 20 minutes and preferably equal to 15 minutes, to perform a first drying phase in a drying oven, for a period of cooking between 15 minutes and 45 minutes, and preferably for a cooking period of 30 minutes, keeping the oven at a temperature between 100 ° C and 150 ° C.

The implementation of phase b. and in particular the application of the first coating layer 12 allows the correct anchoring of the paint on the metal support of the alloy, as well as? optimal adhesion of the materials subsequently applied (as will be seen below) and the sealing of the entire polymeric coating (composed of the various layers 12, 13 described here).

After completing step b., The process 1 according to the invention consists, in step c., In applying at least partially (and preferably completely) to the first layer 12 a second coating layer 13 by means of at least a second painting treatment a spray, using a catalyzed finishing paint (which in the terminology of the sector can also be called "primer topcoat"). Such a finishing paint? configured to ensure an increase in protection from external agents and to provide the desired color.

Pi? in detail, phase c. serves to protect the first layer 12 obtaining greater resistance to external agents (by their nature epoxy polymers are not particularly resistant to UV rays) but also to arrive at the right colorimetric coordinates (L, a, b, deltaE) required, based on the reference master provided by the client.

Furthermore, step c. allows the accessories 10 to better resist the aggression by chemical agents such as chlorinated water, swimming pool or saline water, organic solvents such as MEK (Methyl Ethyl Ketone), acetone, perchlorethylene, etc., as well as? to the main tests in the climatic chamber of the sector.

In particular, in a preferred embodiment, in any case not limiting the application of the invention, step c. at the end of the second painting treatment and after observing a further dust-free period of between 10 minutes and 20 minutes and preferably of 15 minutes, to perform a second drying phase, for a cooking period of between 45 minutes and 1 hour, keeping the oven at a temperature between 60 ° C and 100 ° C, and preferably equal to 80 ° C.

Note how the spray painting treatments, both in phase b. that in phase c., they are preferably (but not necessarily) performed in special booths with manual or semi-automatic cup airbrush (commonly also called spray gun), a pneumatic system that works by atomising the paint by air.

Both for phase b. that for phase c. moreover, the dust-free period (which, as is known, is observed to wait for the coating layer 12, 13 to consolidate and is no longer able to incorporate the dust that settles there) can? be observed by hanging the casting 11 on suitable frames (but other practical choices are not excluded, however falling within the scope of protection claimed herein). The jets 11 can be hung and immobilized on suitable mounting frames also for carrying out the painting treatments.

Subsequently, both for phase b. that for phase c. drying in specific drying ovens (according to parameters chosen according to the technical data sheet of the paint) allows to obtain thicknesses (intended as the sum of the layers 12, 13 of coating applied) ranging from 10 to 50 microns (based precisely on the number of layers 12, 13 applied).

While the composition of the primary paint? preferably the same, regardless of the sector of destination of the accessory 10 which is made by means of the method 1, favorably the invention provides for varying the composition / nature of the finishing paint, precisely according to the sector of destination of the accessory 10.

In particular, usefully the finishing paint? based on a substance selected from the group consisting of an acrylic resin, a polyurethane resin and an acrylate polyurethane copolymer. Pi? particularly, if the accessory 10 is intended for the leather goods sector or the footwear sector, the finishing paint? preferably chosen based on an acrylic resin or a polyurethane resin (glossy / opaque type), while for accessories 10 intended for the clothing sector preferably the finishing paint? based on an acrylpolyurethane copolymer.

In this context, the use of acrylic resins? preferable to polyurethane ones in the case of particular color tones desired by the customer (the final consumer or, more likely, the company that produces or markets the leather goods or footwear), as some colored finishes require a brilliance and vivacity ? colors that are best obtained precisely with the use of acrylic resins.

However, it is emphasized that the possibility is not excluded? to adopt one of the aforementioned types of finishing paint for a sector other than the one mentioned above? was destined, cos? how ? in any case provided for the possibility? to choose different compositions of the finishing varnish (and / or of the primary varnish) with respect to those specifically illustrated in the previous pages.

In any case, whatever the finishing varnish used, it is specified that if you want to give the accessory 10 a transparent finish, the finishing varnish? used as it is (glossy, opaque or in a variable mixture in the case of semi-gloss effects).

Usefully, in the case of colored finishes, the primary paint and / or the finishing paint have an additive consisting of a coloring paste.

In the case of primary paint, such a coloring paste? contained in a percentage by weight of up to 10-15%, with respect to the total weight of the primary paint used.

In the case of the finishing paint, this coloring paste (with organic or inorganic pigments according to the desired color)? contained in a percentage by weight between 15% and 30%, with respect to the total weight of the finishing paint used, in order to achieve the color tone desired by the customer or client.

In an embodiment of significant practical interest, however not limiting the application of the invention, step c. plans to repeat (at least) a second time the second treatment using the same finishing varnish (which is therefore effectively applied twice), to give a greater brilliance (i.e. degree of opacity / gloss) to the accessory 10, especially in the case of colored finishes.

Furthermore, the repetition of the second treatment protects the colored finish in the best possible way, guarantees its long-term durability and generally determines the correct resistance to wear and corrosion, according to the requests.

Advantageously, the method 1 according to the invention can? foresee, in a phase d. following step c., to perform a physical vapor deposition process (also known with the English phrase "Physical Vapor Deposition" or with the corresponding acronym "PVD"), to apply on the second layer 13 a film 14 configured for the transfer of a further surface finishing effect on accessory 10 (otherwise not obtainable by means of spray painting alone).

Some examples of finishes obtainable by implementing phase d. are gold color (TiN finish), ruthenium (TiC), titanium (metallic Ti) and chromium (metallic Cr), which can be made using a titanium target (in the first three cases) or a chromium target (in the first three cases). 'last).

This phase d. it is of particular practical interest for accessories 10 intended for the leather goods or footwear sector (but we reserve the right to implement it also in other application contexts).

In particular, phase d. provides for the use of a reaction gas selected from the group consisting of nitrogen, acetylene and an inert gas configured to transport the metal atoms corresponding to the surface finish to be given to the accessory 10. Pi? particularly, nitrogen or acetylene can be used as inert gas for TiN or TiC finishes, while for the other two it is preferred to use inert gas.

In any case, by varying the quantities? of reagents used and therefore the thicknesses? It is possible to obtain different precious finishes.

Pi? in general, the PVD technique implemented in step d. it allows to reproduce a series of gold, palladium, ruthenium and rose gold colored finishes at different colorimetric coordinates, able to perfectly imitate the characteristic precious galvanic finishes but without using precious material. The thin film 14, which is deposited directly on the second layer 13, also allows to guarantee a great resistance to rubbing and wear.

The deposit is achieved by applying a thin film 14 atom by atom in a coherent manner in a high vacuum atmosphere using a growth technique via sputtering starting from a different metal target and a reactive gas (as already mentioned) according to the finish. choice obtaining variable thicknesses between 0.5 micron and 1.5 micron approximately. A particularly relevant aspect? sustainability of the PVD process: elimination of toxic or harmful heavy metals for the environment (including trivalent or hexavalent chromium, etc.), elimination of the operator's direct contact with the products (as the process takes place inside a chamber at the top remote controlled vacuum) and cost reduction related to precious material.

Favorably, the method 1 according to the invention can? predict, in a phase a '. following step a. and prior to step b. (before starting the painting activities), to perform at least one preliminary treatment on the casting 11, this treatment being chosen from the group consisting of polishing, brushing, sandblasting, vibro-polishing and satin finishing. However, it is planned to perform two or more? preliminary treatments (among those listed above or others) on the same casting 11.

Like the method 1 according to the invention, the object of the present discussion and the protection that it claims is a metallic accessory 10, which can be carried out by means of a method 1 according to what has been illustrated up to now.

Accessory 10? destined to find application in the fashion, clothing, footwear, leather goods and similar sectors.

According to the invention, the accessory 10 comprises at least one cast 11 in magnesium alloy (obtained by high-temperature die-casting, or thix-molding).

The accessory 10 further comprises at least a first layer 12 of at least partial (and preferably complete) coating of the casting 11, comprising a catalyzed primary paint based on at least one epoxy resin and an epoxyacrylic copolymer.

The accessory 10 also comprises a second layer 13 for at least partial (and preferably complete) coating of the first layer 12, comprising a catalyzed finishing paint, configured to increase protection from external agents and to provide the desired color.

Accessory 10 will be able to moreover, it can be endowed with further peculiarities, obtainable by carrying out the method 1 according to the invention (for example a further film 14 obtained by means of the PVD technique).

The implementation of the method 1 according to the invention? was then already? described in detail in the previous paragraphs, but, in summary, it envisages the adoption of a magnesium alloy (of any type, depending on the needs) to produce fashion accessories 10 for leather goods, footwear and clothing by first of all a thix-molding process (step a.) , cos? to give the desired shape to a casting 11.

A series of preliminary treatments (phase a '.) Can then be carried out on this casting 11, such as cleaning, vibratory polishing, brushing or sandblasting (in safe conditions with special machinery) aimed not only at achieving the desired basic aesthetic effect but above all to make the substrate suitable for receiving the subsequent treatment. After phase a '. the first coating layer 12 (phase b.) and the second coating layer 13 (phase c.) are applied by means of respective decorative / protective spray painting treatments, specifically designed for the fashion sector, followed if necessary (phase d.) from the PVD process if particular effect finishes are required that cannot be reached by painting.

Were they already? illustrated the benefits that the various phases of the procedure 1 confer on the accessory 10, but briefly it can? reiterate how the die casting allows to work effectively the magnesium alloy, overcoming the criticalities? that usually accompany it, being able to cos? to transfer its positive peculiarities to the accessory 10? in terms of sustainability? and environmental impact. At the same time, the painting phases, thanks also to the specific choice of paints adopted, on the one hand give the casting 11 (and therefore the accessory 10) the necessary resistance to corrosion, wear and abrasion, on the other hand they allow to obtain the desired finishes.

Pi? in detail, thanks to the steps of the method 1 according to the invention? possible to combine the properties? of the main magnesium alloys, that is the lightness, the excellent machinability? even in the presence of complex geometric shapes, the high resistance, the low production costs, with the sustainability? and reproducibility? of the production processes as well? the possibility? 100% recycling, generating new processing cycles to replace (total or partial) those commonly used in the fashion sector in order to make more? sustainable and even less expensive the finished accessory 10. Procedure 1 does not include the use of nickel or other toxic or allergenic metals, further confirming its sustainability? and the possibility? to implement it safely, respecting the health of the operators involved and the end user.

With spray painting? possible to obtain an infinite number of color finishes and effects (including precious finishes), thus being able? satisfy any aesthetic request of customers and pass any laboratory test (for leather goods / footwear or clothing), and above all you can? protect the underlying material from corrosive phenomena and wear while maintaining compliance standards to the main sector tests.

How to ? underlined in the previous paragraphs, the fashion market is getting more and more? orienting towards sustainability? and the complete recycling of the materials used in its sectors, including that of the accessories sector, while still wanting to maintain quality? and resistance to the main quality laboratory tests. The accessories 10 in magnesium alloy, possibly subjected to preliminary treatments to make it even more? suitable for subsequent spray painting and possibly subjected to a PVD process, they are therefore a real sustainable and recyclable alternative to current processes based on galvanic cycles applied to materials such as brass, zamak and steel. The lightness, the low cost and the capacity? to be easily worked even in complex shapes as well as? the excellent resistances conferred by the subsequent specific treatments with PVD and spray painting make the accessories 10 candidates to replace a good portion of the known accessories made with traditional technologies, potentially being able to ensure high economic and turnover returns.

The invention therefore ensures low environmental impact and sustainability? of the process (from the accessories 10 in easily recyclable material to the various phases of the procedure 1, easily implemented without resorting to toxic substances), high performance and resistance (thanks to the painting treatments and the layers 12, 13 thus applied), while lowering costs.

As a further confirmation of the top-level performance achieved by the accessories 10 obtainable by implementing the method 1 according to the invention, it should be noted that the applicant has internally conducted some tests on them.

Pi? in detail, the accessories 10 in the selected magnesium alloy, suitably pre-treated with polishing, vibratory polishing and satin finishing and then subjected to the appropriate spray painting cycles optimized for the fashion sectors of application (in the case of accessories 10 for leather goods / footwear as such or also with suitable PVD cycles), were tested in the laboratory on the basis of the test specifications for leather goods / footwear and clothing. The accessories 10 were therefore found to comply with the Squaring tests (UNI EN ISO 2409: 2013, excluding paragraphs 4 and 5), Turbula 30min and 1h (ISO 23160: 2011), Moist heat with / without skin 48h / 96h even with pre- turbula (UNI EN ISO 4611: 2011 / UNI EN ISO 17228: 2006 ISO 23160: 2011), Salt Fog 48h / 96h also with pre-turbula (UNI EN ISO 9227: 2012 ISO 23160: 2011), Synthetic Sweat 24h also with pre-turbula -turbula (NF S 80-772: 2010 ISO 23160: 2011), Resistance to MEK (ASTM D 4752), Dry Cleaning (UNI EN ISO 105-D01: 1997) and Domestic Washing (UNI EN ISO 105-C06: 1999 ).

The found, so? conceived,? susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; moreover, all the details can be replaced by other technically equivalent elements.

In the examples of embodiment illustrated, individual characteristics, reported in relation to specific examples, may actually be? replaced with other different characteristics, existing in other embodiments.

In practice, the materials used, as well as? the dimensions may be any according to the requirements and the state of the art.

Claims (10)

CLAIMS 1. Process for manufacturing metal accessories (10), for the fashion, clothing, footwear, leather goods and similar sectors, which consists of: to. die-casting a cast (11) in magnesium alloy, b. at least partially cover the casting (11) with a first coating layer (12) by means of at least a first spray painting treatment, using a catalyzed primary paint based on at least an epoxy resin and an epoxy-acrylic copolymer, c. apply at least partially on the first coating layer (12) a second coating layer (13) by means of at least a second spray painting treatment, using a catalyzed finishing paint, configured for an increase in protection from external agents and for conferring the desired coloring. 2. Process according to claim 1, characterized in that said step b. provides, at the end of said at least a first painting treatment and after a further dust-free period of between 10 minutes and 20 minutes and preferably equal to 15 minutes, to carry out a first drying phase in a drying oven, for a period cooking time between 15 minutes and 45 minutes, and preferably for a cooking period of 30 minutes, keeping the oven at a temperature between 100 ° C and 150 ° C. 3. Process according to claim 1 or 2, characterized in that said step c. provides, at the end of said at least a second painting treatment and after a further dust-free period of between 10 minutes and 20 minutes and preferably of 15 minutes, to carry out a second drying phase, for a cooking period of between 45 minutes and 1 hour, keeping the oven at a temperature between 60? C and 100? C, and preferably equal to 80? C. 4. Procedure, according to one or more? of the preceding claims, characterized in that the finishing paint? based on a substance selected from the group consisting of an acrylic resin, a polyurethane resin and an acrylate polyurethane copolymer. 5. Procedure, according to one or more? of the preceding claims, characterized in that the primary paint and / or the finishing paint have an additive consisting of a coloring paste. 6. Procedure, according to one or more? of the preceding claims, characterized in that said step c. provides for repeating said second treatment a second time using the same finishing varnish, in order to give the accessory a greater brilliance (10). 7. Procedure, according to one or more? of the preceding claims, characterized in that it provides, in a step d. subsequent to said step c., to carry out a physical vapor deposition process, to apply on the second layer (13) a film (14) configured to give a further surface finishing effect to the accessory (10). 8. Process according to claim 7, characterized in that said step d. provides for the use of a reaction gas selected from the group consisting of nitrogen, acetylene and an inert gas configured to transport the metal atoms corresponding to the surface finish to be given to the accessory (10). 9. Procedure, according to one or more? of the preceding claims, characterized in that it provides, in a step a '., subsequent to said step a. and prior to said step b., to carry out at least one preliminary treatment on the casting (11), chosen from the group consisting of polishing, brushing, sandblasting, vibratory polishing and satin finishing. 10. Metallic accessory, achievable by means of a method (1) according to one or more? of the preceding claims, characterized in that it comprises at least: - a cast (11) in magnesium alloy, - a first layer (12) for at least partial coating of said jet (11), comprising a catalyzed primary paint based on at least an epoxy resin and an epoxy-acrylic copolymer, - a second layer (13) for at least partial coating of said first layer (12), comprising a catalyzed finishing paint, configured to increase protection from external agents and to give the desired color.