WO2012153299A1

WO2012153299A1 - An accessory element for decoration made of a zinc aluminium alloy

Info

Publication number: WO2012153299A1
Application number: PCT/IB2012/052345
Authority: WO
Inventors: Annalisa POLA; Lorenzo MONTESANO; Roberto Roberti; Michele Tosti
Original assignee: Entech S.R.L.
Priority date: 2011-05-12
Filing date: 2012-05-11
Publication date: 2012-11-15

Abstract

It is provided an accessory element (1) for garments for example consisting of buckles, accessories for belts, handles, fastening elements for bags and jewellery objects and comprising at least one component (2) made of a zinc alloy including aluminium in a percentage included between 13% and 25% and magnesium in a percentage lower than 0.1 % which does not comprise bismuth and lead or keeps them both within percentages lower than 0.004%.

Description

AN ACCESSORY ELEMENT FOR DECORATION MADE OF A ZINC ALUMINIUM ALLOY

The present invention relates to an accessory element for decoration, of the type pointed out in the preamble of the first claim.

In particular, the present invention pertains to accessory elements creating fastening parts for portions of articles of clothing or garments or decorative parts of garments, trinkets, parts of glasses, three-dimensional logos for decoration, zips and fastening elements, watches and mechanisms thereof, sliders for zips, buckles, belt accessories, handles, fastening elements for bags, applications for shoes, buttons and jewellery objects such as necklaces, brooches, bracelets, rings and earrings, etc.

It is known that accessory elements for decoration of the greatest value are those made of metal material that, in addition to the high aesthetic quality, offer good reliability and duration.

In detail, these accessory metal elements are made mainly using brass, i.e. a copper-zinc alloy, to which depending on the requested features, other elements are added such as manganese, lead, tin, iron and aluminium or also using a zinc alloy, commercially referred to as Zamak^®, which has aluminium, copper and magnesium as the main components.

The accessory elements for decoration made of brass are usually obtained by hot moulding or chip removal machining on numerical control machines.

On the contrary, the Zamak^® elements, being this alloy characterised by a low melting point and high flowability, are made by die-casting, in particular by the known hot chamber die casting process, or by spin casting, in case of small or very small series or amounts.

Finally, in order to have an aspect of greater quality, these accessory metal elements usually have a coating obtained by painting or, in most cases, by electroplating that can be followed by physical vapour deposition (PVD).

The known art mentioned above has some important drawbacks.

In fact, known accessory elements, made by moulding, have poor working accuracy, which is on the contrary fundamental for these accessories. Instead, the elements made of Zamak^® do not enable different portions to be welded together, reducing the possibility of producing particular components of complicated geometry.

In addition, the accessory elements made of Zamak^® presently used for garments have reduced duration, in particular due to the reduced resistance to shocks, which resistance in conventional Zamak^® alloys is greatly affected by the presence of cuts (scratches, etc.).

This defect is particularly important in zip-pulling elements, bags, belts, where these elements are continuously submitted to forces and stresses leading to quick breaking of same. The accessory element therefore represents the critical component of a bag or a belt both because it is frequently submitted to breaks and because breaking in many cases brings about the impossibility of successive use of same.

This problem is still more important in elements for decoration made of Zamak^®. In fact, obtaining pieces made of Zamak^® by die-casting (i.e. high pressure and highspeed injection of the alloy into the die ) makes the objects have a high porosity degree that causes a reduction in the mechanical performances and aesthetic properties of the product.

Another problem is represented by the high weight that, in some cases, makes the accessory element particularly uncomfortable to carry. A defect belonging above all to the accessory elements made of brass, is represented by the high manufacturing cost due both to the cost of the material used, and to the necessary manufacturing temperatures. A further problem connected with use of brass concerns the possible chip removal machining operations: in this material, in fact, some Pb is commonly added for improving the workability features thereof. However, as known, this element is dangerous and polluting and therefore its presence is undesirable.

To obviate the mentioned drawbacks suitable zinc alloys have been made which have better mechanical features as compared with Zamak^®.

In some of these alloys the high workability and physico-chemical features are given by particular elements such as lead, bismuth and still other elements.

In particular, patent US-B-3880679 discloses a particular zinc alloy using bismuth to improve the chemical features of the compound.

However lead is considered damaging to the environment in particular during the disposal step. In addition it is not yet clear how bismuth can be disposed of, and also still unknown are the potential damaging effects that the later could cause to the environment.

Another type of alloy is described in patent JP-A-06049572. These alloys have good physico-mechanical features in particular given by the high amount of copper or a particularly high amount of aluminium. However these alloys are not workable using chip removal tools but can be treated only by casting.

Under this situation, the technical task underlying the present invention is to conceive an accessory element for garments capable of substantially obviating the mentioned drawbacks.

Within the scope of this technical task, it is an important aim of the invention to conceive accessory elements characterised by reduced costs and high aesthetic quality.

An important aim is to make an accessory element that is lighter and therefore more comfortable when worn.

Another aim of the invention is represented by the possibility to make elements for garments of long duration.

A still further aim is to obtain accessory elements without lead and bismuth, as required by many international regulations.

The technical task and the aims specified are achieved by an accessory element for garments as claimed in the appended claim 1.

Preferred embodiments are highlighted in the sub-claims.

The features and advantages of the invention are hereinafter clarified by the detailed description of a preferred embodiment of the invention, with reference to the accompanying drawings, in which:

Fig. 1 shows an accessory element for decoration according to the invention consisting in a bottom;

Fig. 2 is a section of Fig. 1 ;

Fig. 3 diagrammatically shows a process for manufacturing an accessory element;

Fig. 4 shows an assembly of accessory elements for decoration respectively consisting in a zip-pulling element, a pair of glasses including a logo, a watch, a buckle.

With reference to the drawings, the accessory element for decoration according to the invention is generally identified by reference numeral 1.

In particular, the present invention concerns accessory elements forming fastening elements for portions of articles of clothing or garments or ornamental parts of garments, trinkets, parts of glasses, three-dimensional logos for decoration, zips and fastening elements, watches and mechanisms thereof, sliders for zips, buckles, belt accessories, handles, fastening elements for bags, applications for shoes, buttons and jewellery objects such as necklaces, brooches, bracelets, rings and earrings, etc.

It can therefore comprise one or more components adapted to be joined together in such a manner as to form the accessory element 1.

In detail, the accessory element 1 comprises at least one component 2 made of an advantageous zinc alloy comprising aluminium in a percentage included between 13% and 25% and magnesium in a percentage lower than 0.1% and preferably also copper in a percentage lower than 5%.

Preferably, said alloy has a copper percentage included between 0.2% and 3.5%, an aluminium percentage included between 13% and 25% and a zinc percentage substantially included between 70% and 87%. More preferably, the zinc percentage in this alloy is included between 75% and 85%.

In detail, two preferred compositions have the following formulations. First composition: aluminium 15%+1%, magnesium 0.04%+0.02%, copper 1 %+0.5%, zinc for the balance. Second composition: aluminium 22%+1 %, magnesium 0.04%+0.02%, copper 2%+0.5%, zinc for the balance

In said alloy, in addition to zinc, aluminium, copper and magnesium, impurities may be present, i.e. other substances different from those listed above and present in percentages lower than 0.05%. In detail, among the impurities it is possible to have: iron in a maximum concentration of 0.02% because it increases brittleness; cadmium present in percentages not exceeding 0.0015% because it makes the mechanical properties worse and induces inter-crystal corrosion; and tin that is present in the alloy in the maximum concentration of 0.002% because it makes the mechanical properties worse and induces inter-crystal corrosion. Lead, bismuth and nickel have a content lower than 0.004% and preferably of 0.001 %. In some cases, in order to improve the aesthetic value and resistance of the accessory element 1 , each component 2 can have a coating 3 adapted to cover almost the whole of the component itself.

In particular, coating 3, as hereinafter better described, can have one or more layers each of which can be obtained by painting, electroplating, high-vacuum plating (by Physical Vapour Deposition for example, identified with the abbreviation PVD) or any other process suitable to enable a layer of coating 3 to be created.

In particular, coating 3 consists of a single layer made by electroplating and, therefore it can comprise substances adapted to improve the resistance of the accessory element 1 (nickel, chromium, for example) and/or substances adapted to give high aesthetic value to element 1 such as silver, gold, platinum, palladium, ruthenium, rhodium or some gold and palladium alloys, for example.

The invention comprises a new manufacturing process 10 for an accessory element 1 for garments.

This manufacturing process 10, diagrammatically shown in Fig. 3, contemplates a definition step 20 in which the shape of the accessory element 1 is substantially defined. In particular, the definition step 20 contemplates at least one shaping substep 21. The shaping substep 21 is preferably carried out by hot moulding or spin casting, gravity casting or die-casting, which processes are known by themselves. In particular for mass production, a hot moulding process is used and for single elements or elements in very small amounts, for example used for fashion shows, the spin casting process is used.

Once the shaping substep 21 has been completed, the manufacturing process 10, above all in case particularly complicated accessory elements 1 are wished to be produced which therefore are made up of several components 2, can contemplate a welding step 22 in which the just made components are connected to each other by welding or other similar operation.

Once the shaping substep 21 or welding substep 22 (if any) is over, the definition step 20 can contemplate a following finishing substep 23 in which the component 2 is machined by a chip-removal process in a numeric control machine or other similar device. The chip removal substep in many cases can be an alternative to the shaping substep.

After the above, there is another step consisting in a mechanical brushing and polishing operation 25 carried out manually or by means of cleaning robots, which can be replaced by or integrated with a mass vibration process with abrasive chips (tumbling).

At this point, the process 10 contemplates a coating step 30 in which a coating 3 is made which is adapted to cover component 2 and then the accessory element 1.

This step 30 can have one or more substeps, each of which is adapted to form a coating layer 3. In particular, in the coating step 30 one or more substeps can be identified, each of which is adapted to form a particular layer. It can therefore have an electroplating substep 31 , a high-vacuum plating substep 32, and a painting substep 33. In detail, in the electrodeposition substep 31 , a component 2 is covered with a metal layer utilising one of the known electrodeposition techniques.

In the high vacuum deposition 32 a layer of nanoparticles is obtained through, for example, the known Physical Vapour Deposition (often abbreviated PVD) technique or the Chemical Vapour Deposition (abbreviated CVD) technique.

Finally, in the painting substep 33 a coating layer 3 is formed through cataphoresis or other painting technique.

Preferably, the coating step 30 contemplates at least one electrodeposition substep 31.

In case of accessory elements 1 characterised by assembly of several components such as jewellery elements 1 , the manufacturing process 10 may comprise a mounting step 40 during which the different components are assembled to each other forming the accessory element 1 .

The invention achieves important advantages.

A first advantage is given by the possibility of using the same alloy both in producing pieces by known foundry techniques (e.g. die-casting, spin casting, etc.) and by hot moulding. The same material is therefore usable both for mass production, commonly obtained by hot moulding or die-casting, and for single pieces, commonly obtained by spin casting or machining from solid pieces.

The material is therefore very versatile and can remain the same for the prototypes and the mass production with many advantages in terms of simplicity and accuracy of prototyping.

The accessory element further has high accuracy, which is fundamental for the described elements 1 . Accuracy can be obtained both by hot moulding and die- casting, and even by welding. In addition, the accessory element 1 for garments is characterised by great resistance and much longer duration than known accessory elements made of Zamak^®. This duration is fundamental in particular for zip-pulling elements, zips, fastening elements for jewellery, logos, etc.

These particular features are substantially due to use of the particular zinc alloy giving element 1 high capability to withstand the stresses to which these accessory elements are normally submitted.

Greater resistance and duration are further obtained due to coating 3 enabling the resistance of element 1 to be further increased.

Another advantage is the alloy weight that, as compared with that of brass and Zamak^®, is 20% and 15% less respectively, so that the lighter accessory element 1 is more comfortable and practical when carried or worn.

A further advantage due to the absence of lead and bismuth consists in the possibility of having elements 1 without toxic substances and therefore less dangerous to the user, of simpler disposal and in compliance with the international regulations.

In addition, the absence of lead and bismuth makes the accessories easily recyclable.

An important goal reached by the present invention is represented by the reduced manufacturing cost of elements 1 thus obtained, by virtue of the reduced cost of the alloy used, and the reduced environmental impact due to the low melting and hot moulding temperatures as compared with those necessary with brass.

This reduced cost is further due to the high workability of the zinc alloy that therefore enables a manufacturing process 10 to be adopted that comprises simple machining operations. In fact, as previously described, components 2, made of the zinc alloy, lend themselves to be submitted to machining operations such as chip removal much better than when Zamak^® is used, In particular, this is due to the fact that the copper content does not exceed 5% so as to obtain ideal chips in the chip-removal machining processes.

The possibility of obtaining complicated accessory elements 1 is further ensured by the possibility of carrying out welding operations which are not possible in elements made of Zamak^®.

Also important is the fact that these accessory elements 1 have a good aesthetic quality. This advantage is obtained due to the possibility of carrying out a coating 3 of a material of high aesthetic value such as, for example, silver, gold, platinum, palladium, ruthenium, rhodium or alloys of some of them. Finally, the particular alloy used has high features of resistance to oxidation so that it is possible to store high amounts of uncoated accessory elements 1 and carry out coating 3 later on so as to optimise the logistics connected with the storage itself.

This solution was absolutely impossible in products made of Zamak^®, because Zamak^® is strongly subject to oxidation and therefore it must be immediately coated. This greater resistance to oxidation and therefore to corrosion is also a characteristic of the pieces that have been submitted to the previously described coating and protection steps (electroplating, painting, PVD).

Other experiments concerning use of the described alloy, out of the protection scope of the present patent, have concerned the manufacture of: components of systems of the automotive sector, components of motorcycles and bicycles, accessories for furniture, kitchens, household appliances and items, components for illuminating engineering, electric accessories and electric plates, machines for foodstuffs, sanitary fixtures and apparatus in the medical sector, nautical elements, sports accessories and sports equipment, aeronautical accessories, accessories for weapons.

Claims

1. An accessory element (1 ) for decoration, characterised in that it comprises at least one component (2) made of a zinc alloy including aluminium in a percentage included between 13% and 25%, copper in a percentage lower than 5% and magnesium in a percentage lower than 0.1 % which does not comprise bismuth and lead or keeps them both within percentages lower than 0.004%..

2. An accessory element (1 ) as claimed in claim 1 , wherein the zinc percentage in said alloy is included between 70% and 87%.

3. An accessory element (1 ) as claimed in one or more of the preceding claims, wherein the aluminium percentage in said alloy is included between 13% and 25%.

4. An accessory element (1 ) as claimed in one or more of the preceding claims, wherein said alloy does not comprise bismuth and lead or keeps them both within percentages lower than 0.001 %.

5. An accessory element (1 ) as claimed in one or more of the preceding claims, wherein said alloy does not comprise nickel or keeps it within amounts lower than 0.004%

6. A manufacturing process (10) adapted to create an accessory element (1 ) for decoration, said manufacturing process (10) comprising a definition step (20) in which the shape of said accessory element (1 ) is substantially defined; and characterised in that said definition step (20) comprises at least one shaping sub-step in which a component (2) of said accessory element (1 ) is made using a zinc alloy including aluminium in a percentage in the range of 13% to 25%, copper in a percentage lower than 5% and magnesium in a percentage lower than 0.1 %, which does not contain bismuth and lead or keeps them both within percentages lower than 0.004%.

7. A manufacturing process (10) as claimed in the preceding claim, wherein said definition step (20) consists of hot moulding .

8. A manufacturing process (10) as claimed in the preceding claim, wherein said definition step (20) consists of a spin casting process.