Technical field
[0001] The present invention relates to a method for producing precious material for ornamental
articles and to precious material for ornamental articles which can be obtained in
particular by means of this method.
[0002] The method and the precious material according to the present invention may advantageously
be used in the manufacturing industry for the production of precious semi-finished
articles.
Background art
[0003] As is known, gold, silver and platinum are precious metals which are widely used
in the production of articles of jewellery, among other things because of their malleability
and ductility and their aesthetic characteristics.
[0004] Generally precious metals are not used in the pure state, but alloyed with other
metals, in order to modify their mechanical properties, their aesthetic characteristics
and in particular their colour or also only the "carat value" and therefore the cost
of the ornamental articles obtained with these metals.
[0005] In more detail, as is known, in the gold and silverware sector, the precious metal
content of a product is usually indicated by means of an index called the "purity
index" which is generally expressed as a fraction of the metal, in thousandths, relative
to the total weight of the said product. The said index may also be expressed in carats
(K), in this case the fraction of metal relative to the overall weight of the product
being expressed in twenty-fourths (1/24), instead of thousandths as with the purity
index. The platinum alloys which are currently used in the precious metals industry
have purity indices which are standardized and equal to 850/1000, 900/1000 or 950/1000,
while the purity indices for gold typically are equal to 18 carats (75.0%) for southern
Europe; 24 carats 'Chuk Kam' (minimum 99,0%) for the Far East (China, Hong Kong, Taiwan);
22 carats (91.6%) for India; 21 carats (87.5%) for the Arab countries; and 8-18 carats
(33.3 - 75.0%) for northern Europe and the USA.
[0006] Apart from the constraints imposed by the carat value or the minimum amount of precious
metal which must be contained in an ornamental article, during production of the alloys
for the gold and silver industry it is necessary to take into account also other factors
such as the mechanical properties and "anti-allergy" properties.
[0007] The mechanical properties must be such as to allow the use of the alloys in the standard
processes and treatments employed in the gold and silver industry (ease of melting,
weldability, diamond-machinability, possibility of recovering and reusing the waste
product, etc.). It is in fact evident that the alloys must at least not require complex
processing techniques such that their use becomes uneconomical.
[0008] In most cases the gold and silver articles are worn in direct contact with the skin
and therefore must ensure anti-allergic properties which allow the said articles to
be worn also by persons who are more sensitive.
[0009] For this purpose it is known, for example, that the alloys for gold and silverware
must ensure a slow release of allergy-producing agents such as nickel and cobalt.
[0010] For each precious metal alloy the choice of the purity index and the metals which
form the alloy together with the precious metal, in terms of both alloy base elements
and alloying elements, therefore generally depends on commercial factors and the type
of product which is to be obtained.
[0011] The metal elements which are currently most used for gold alloys are: silver (Ag),
copper (Cu); zinc (Zn); indium (In); palladium (Pd); nickel (Ni); while those most
used for platinum alloys are: cobalt (Co), iridium (Ir), gold (Au), palladium (Pd),
rhodium (Rh) and ruthenium (Ru)
[0012] In order to satisfy the various mechanical and aesthetic requirements of the ornamental
articles, new alloys have been proposed, said alloys being obtained by introducing
into their composition not only metal alloying elements or base elements, but also
vitreous materials or plastic materials.
[0013] In more detail, the patent
US 4,476,090 describes an alloy for articles of jewellery with a low density, which is composed
of a noble metal or a noble metal alloy and by glass in a percentage amount of between
1 and 70 %.
[0014] One drawback of this alloy consists in the fact that it can be cast in a mould, but
cannot be pressed. A further drawback consists in the fact that it has mechanical
and in particular elasticity properties which are not suitable for the production
of jewellery intended for ornamental purposes.
[0015] The patent
US 5,578,383 describes an alloy for articles of jewellery with a low density, which is composed
of a noble metal or a noble metal alloy in a percentage amount of between 33 and 99%
and a percentage amount of between 1 and 67% of a thermosetting crosslinkable polymer.
[0016] In accordance with the production techniques described in the two abovementioned
patents, the end product is obtained by mixing two or more mutually reactive liquid
precursors which are poured into a mould and which, as a result of their mutual reaction,
are converted into a crosslinked solid which cannot be shaped by the action of heat.
[0017] In other words, the articles of the type described hitherto all have the drawback
that they require a complex production process which is not practical and unsuitable
for achieving a high dispersion of the metallic powder within the polymer or vitreous
matrix, which is able in particular to ensure the same concentration or the same purity
index at all points within the product.
[0018] Although these alloys have good stability characteristics, often the metallic powders
contained in the polymer matrix do not form strong bonds and may therefore be easily
released by the surface of the finished articles and therefore dispersed in the environment.
[0019] Moreover, mixing of components with such varying characteristics such as metals and
polymers is not performed using methods able to ensure that optimum mechanical characteristics
such as elasticity and surface micro-roughness are achieved in the finished products.
[0020] The patent
US 4,282,174 describes a technique for producing articles for the gold and silver industry which
envisages producing beforehand plastics powders with very fine dimensions and combining
the plastics powders with metal powders having dimensions of between ½ and 50 micron,
resulting in a mixture of powders which are used for pressing at high pressures and
at temperatures of between 100 and 250°C in order to obtain the articles with the
desired shape and size.
[0021] A first drawback of the production process described in this patent consists in the
use of complex processes in order to obtain the pulverized plastic material.
[0022] A second drawback consists in the use of thermoplastic polymers such as polyethylene,
polystyrene, polymethylmethacrylate and polyamide which have a limited resistance,
namely a high hardness factor and poor elasticity.
By way of example the typical elongation values of the materials mentioned are given
below:
- Polyamides: 5-200 %;
- Polyesters: 3-5%
- Polymethylmethacrylate: 1.5 - 10%;
- Low-density polyethylene: values higher than 400%, but with 20% expansion under pulling
stress, namely the polymer stretches irreversibly. Moreover, it has a melting temperature
in the range of 100 - 115°C and a Vicat softening temperature B/50 <40°C, resulting
in this polymer having a limited consistency already at low temperatures and therefore
being unsuitable for use in the production of gold and silverware articles.
[0023] Therefore the materials considered in the abovementioned patent
US 4,282,174 are not suitable for obtaining materials and articles with satisfactory mechanical
important properties. It is in fact extremely important to obtain precious materials
which are sufficiently resistant and elastic such that they do not disintegrate with
time and, during the use in question, are also able to guarantee the economic value
of the articles which they must produce.
[0024] The production method for forming the ornamental articles is performed by dry mixing
the particles of the polymer component and metal component in the powder state and
then by means of subsequent injection in a mould.
[0025] This production method has, in practice, proved to be unsuitable for obtaining jewellery
with superior mechanical properties and in particular with a highly uniform dispersion
of the precious metal in the polymer matrix.
[0026] It should be pointed out again that the technologies known hitherto, for mixing polymer
compositions with precious metal powders in order to produce jewellery, have adopted
dry mixing of the powders of the two materials. These technologies have been unable
to achieve a satisfactory dispersion of the metal powders in the polymer matrix such
as to obtain a homogenization able to produce ornamental articles which have superior
mechanical properties and a purity index which constant at all points in the product
mass.
Disclosure of the invention
[0027] In this situation, the main object of the present invention is to provide a method
for producing a precious material for ornamental articles which allows a homogeneous
product to be obtained, having mechanical properties which are able to ensure a notable
degree of comfort when the product is worn and are distinguished by a high elasticity.
[0028] Another object of the present invention is to provide a precious material for ornamental
articles which is extremely homogeneous and able to ensure a highly uniform concentration
of the constituents throughout the product.
[0029] A further object of the present invention is to provide a method for producing a
precious material for ornamental articles which is simple to produce and operationally
entirely reliable.
[0030] A further object of the present invention is to provide a precious material for ornamental
articles which has a homogeneous concentration of precious metal and a high elasticity.
[0031] These and other objects are all achieved by the method for producing a precious material
for ornamental articles and by the ornamental articles which can be obtained in particular
by means of this method, in accordance with the accompanying claims.
Detailed description
[0032] The technical features of the invention, in accordance with the abovementioned objects,
may be clearly determined from the contents of the claims below and the advantages
therefore will emerge more clearly from the detailed description which follows, provided
with reference to a purely exemplary and non-limiting embodiment of the said invention.
[0033] The precious material according to the present invention may be advantageously used
as an intermediate product in the jewellery industry in order to produce ornamental
articles which contain percentages of precious metal which are equal to those of any
precious-metal alloy, improving the mechanical properties such as, in particular,
the elasticity.
[0034] Alternatively, this intermediate product may be used, not only for forming an ornamental
article of jewellery but also for forming accessories or inserts for products in the
clock and watch-making, spectacles, clothing, footwear and/or leatherwear sector,
since these precious materials - precisely because of their elasticity and resistance
- are, at suitable thicknesses, suitable for stitching.
[0035] The method envisages a step for preparation of a powder of one or more precious metals
present individually, or in an alloy or in combination. This powder is formed with
particles having an average size of less than 0.5 micron.
[0036] In particular the precious metals are chosen from the group containing: gold, silver,
platinum or alloys thereof.
[0037] The components of a thermoplastic polymer composition are then prepared and introduced
in granular form or separately by means of a first gravimetric metering device in
an overall percentage by weight ranging between 30 and 95%, inside a plasticization
chamber of an extruder.
[0038] The percentages of powders and polymeric composition are chosen depending on the
purity index (or the percentage of precious metal) which is ultimately to, be obtained
in the finished product.
[0039] The chamber of the extruder is heated to a temperature of between 120 - 220 °c in
order to melt and mix thoroughly the constituents of the thermoplastic composition.
[0040] By means of a second gravimetric metering device the metallic powder is then introduced
and dispersed within the liquid thermoplastic polymer composition, in an overall percentage
amount by weight ranging between 30 and 95% chosen so as to obtain the desired purity
in the finished product.
[0041] The plasticization chamber (cylinder) has inside it one or more screws (or augers)
composed of conveying segments and mixing segments which, at the cylinder temperature
of between 120 and 220°C and at predefined speeds of rotation, perform optimum mixing
of the polymer composition in the liquid state and the amount of powder/metallic powder
which obviously does not reach the melted state.
[0042] The extruder used will preferably be one of the single-screw or twin-screw high-shear
type able to achieve homogeneous dispersion of the precious metal within the liquid
polymer matrix.
[0043] Considering that the components of the precious metals have substantially different
specific weights and that it is of fundamental importance to prevent sedimentation
of the metal in order to avoid a discontinuity in the composition, as an alternative
to the gravimetric metering devices, it is possible to use in accordance with a further
embodiment of the present invention, also predispersed compositions of precious metal
in low-melting thermoplastic polymers, compatible with the base polymer.
[0044] The liquefied mix of metallic powders in the polymer matrix undergoes extrusion,
producing an intermediate product in the form of a bead (and/ or thin strip).
[0045] The intermediate product obtained from the abovementioned extrusion operation is
a composite (or "compound" in the technical jargon of the sector) namely a combination
of several materials which are thoroughly mixed together.
[0046] Examinations carried out on various points of the bead samples produced results for
the percentage precious metal content which corresponded to the purity index initially
established, thus demonstrating the perfect homogeneity achieved.
[0047] Finally, the bead may be used as a base material for a step involving forming of
the ornamental articles which is to be produced.
[0048] Preferably, upon leaving the extruder, the intermediate product in the form of a
bead will be cut or shaped into granules having the same original purity index in
the form of prismatic, spherical or cylindrical elements.
[0049] For the purposes of the present invention it is important that the mixing step which
results in formation of the intermediate product should be separate from the forming
step. As a result it is possible to optimize the extrusion conditions in terms of
solely the mixing constraints, with the advantage of obtaining an intermediate product
which is extremely homogeneous.
[0050] Advantageously, the intermediate product may be stored for subsequent use in the
forming process which may therefore be performed in a location different from that
for production of the intermediate product and also at a considerably later time.
[0051] The forming operation which results in the production of the ornamental articles
with the desired carat value may envisage, in accordance with a preferred solution
of the present invention, supplying the granular intermediate product to an injection
moulding press, or an intrusion moulding press or a compression moulding press, operating
at temperatures of between 120 and 220°C.
[0052] Using these conversion technologies it is possible to obtain articles which are shaped
with the final form or parts which are overmoulded onto pre-formed parts.
[0053] Alternatively, the forming step may envisage supplying the intermediate granular
product to an extrusion machine operating at temperatures of between 120 and 220°C,
obtaining continuous shaped profiles.
[0054] By way of yet another alternative, the forming step may envisage supplying a cylinder
calendering machine so as to obtain a continuous flat and/or foil-like strip which
may or may not be embossed and which may undergo further processing steps in order
to obtain the finished product.
[0055] The intrusion moulding press, the compression moulding press, the extrusion machine
for obtaining continuous shaped profiles and the cylinder calendering machine for
obtaining a continuous strip are machines which are well-known per se to a person
skilled in the art and for this reason are not described in detail; however their
use in the forming process, based on the intermediate product described, is entirely
novel and original.
[0056] Once the product has been formed it may undergo other processing operations in order
to produce the finished product, which may also be stitched onto a fabric.
[0057] The present invention also relates to a precious material for ornamental articles
which can be obtained as an intermediate product of the method described above.
[0058] Similarly, the method described above may be further characterized with reference
to the characteristics of the precious material indicated in the description which
follows.
[0059] The precious material is obtained as explained above by starting with a suitable
amount of precious metal powders present in an alloy or individually with an average
size of less than 0.5 micron and by an amount of a homogeneous thermoplastic polymer
composition, which amounts are mixed in an extruder.
[0060] In greater detail, the polymer composition comprises thermoplastic polymers which
are obtained by means of polycondensation of one or more resins which are chosen from
the group comprising: thermoplastic polyurethanes, copolysters and copolyamides.
[0061] These thermoplastic polymers may be further elastomerized with compatibilized styrene
block resins and/or with other known elastomerizing agents such as nitrile and butadiene
resins.
[0062] A particular polymer composition which is particularly sui table for the use according
to the objects of the present invention is, by way of example, represented by a thermoplastic
polyurethane obtained by means of reaction between aromatic and aliphatic isocyanates,
ester base polyols, glycol polytetramethylene ester, carbonate ester with a molecular
weight of between 1000 and 4000 and diol chain extenders with a molecular weight of
50 to 400; this reaction may be achieved either by means of the two-step process,
which envisages supplying the liquid monomers into a reactive extruder in an operating
condition such as to favour the formation of a solid intermediate product, which is
subsequently re-extruded and granulated in a second non-reactive extruder, or using
the prepolymer process, which envisages a first reaction inside a chemical reactor
between part of the components of the formulation, resulting in a reactive liquid
intermediate product (called "prepolymer") subsequently supplied together with the
remaining components of the formulation into a reactive extruder, or using "one-shot"
reactive extrusion technology in which all the monomers are supplied into the reactive
extruder, the operating mode of which is configured to obtain the granulated finished
product.
[0063] Preferably, the thermoplastic polyurethanes comprise aliphatic isocyanates, carbonate
esters of the medical type with a molecular weight of between 400 and 4000, and chain
extenders with a molecular weight of between 50 and 400.
[0064] The choice of this particular type of thermoplastic polyurethane is advantageously
due to the particular biostability which makes it suitable for contact with the skin
of any person wearing the ornamental product.
[0065] The thermoplastic composition must have non-toxic, anti-allergic and anti-microbial
properties since it has to come into contact with the human skin.
[0066] For this purpose the polymer composition or the precious material also comprise an
additive with an anti-microbial action incorporated during the production method in
a plasticization chamber and preferably consisting of solution of 2-octyl-2H-isothiazol-3-one
and Triclosan, which is known by the tradename of "Sanitized", and is present in percentage
amount varying from 0.3 to 1% by weight.
[0067] The precious material composition also contains UV and temperature stabilizers in
an amount suitable for best determining the properties thereof as regards resistance
to ageing and formation of bacterial colonies.
The precious material has an elongation at break value in the range of 200 - 800 %
and a hardness factor of between 50 Shore A and 70 Shore D.
[0068] By way of a non-exhaustive illustration, the following example is given.
[0069] 170 g of aliphatic TPU with carbonate ester base (hardness Shore A 73) are mixed
thoroughly inside the extruder with 300 g of gold having a purity index of 916 (22
carats) in a single-screw extruder at 160 - 180°C and cut into granules using a knife
cutter after cooling in water.
[0070] The granules thus obtained were dried in an oven at 70°C for two hours and then processed
at 160°C in a hot-cylinder calender so as to obtain a sheet of thermoplastic precious
material with a gold purity index of 586 (14 carats).
[0071] This precious material has the following physical and 5mechanical characteristics:
- hardness Shore A: 60 (ASTM D 2240)
- breaking load: 8.1 Mpa (ASTM D 412)
- elongation at break: 630 % (ASTM D 412).
[0072] Precious metals such as gold, silver and platinum are heavy metals with a density
much greater than that of the thermoplastic composition in which they are dispersed
inside the precious material.
[0073] Therefore, an ornamental article also with a high carat value (precious metal percentage)
will be distinguished by a volume of polymeric composition which is far greater than
the volume of metallic component.
[0074] For example, considering that gold is a heavy metal with a density of 19.3 g/cm3
and that the density of an elastomer composition indicated above may vary between
1 and 1.5 g/cm3, it follows that the volumetric ratio of gold and elastomer composition
is substantially biased in favour of the latter.
[0075] In other words, very roughly, an 18-carat precious material could be formed by 75
parts by weight of gold and 25 parts by weight of elastomer polymer which, in terms
of volume, may be represented by 3.88 cm3 of gold and 20.83 cm3 of elastomer with
a density 1.2 g/cm3.
[0076] The precious material obtained according to the method and according to the characteristic
features of the invention described above allows a high dispersion of the metallic
powders inside the elastomer plastic matrix, guaranteeing the purity and the mechanical
performance throughout the finished product and ensuring a surprising and favourable
tactile feel.
[0077] With the precious material according to the invention, it is possible to produce
ornamental articles with the desired purity index (i. e. with a guarantee as to the
desired percentage of precious metal) such as, for example, in the gold and silverware
sector, necklaces, bracelets, rings, earrings, etc., which have a final aesthetic
appearance which is distinguished by a highly appreciated tactile feel and by mechanical
properties represented in particular by the hardness and the elasticity which allow
extremely versatile use of the precious material.
[0078] The cost of these articles, considering the simplicity and the repetitiveness of
the production process, and in particular of the forming process, is less than the
cost of the conventional method for producing precious metal articles since it does
not envisage the surface treatments such as polishing and diamond-machining which
form part of the conventional process.
[0079] Advantageously the use of the precious material according to the present invention
is not limited solely to the jewellery sector, but also extends to other sectors for
example the clock and watch-making, gift article, clothing, footwear or leatherwear
sector, considering the fact that these elastic and resistant precious material, at
suitable thicknesses, can be stitched.
1. Method for producing a precious material for ornamental articles, which comprises:
- a step for preparing at least one powder of one of more precious metals present
individually, or in an alloy, or in combination;
- a step for preparing at least one thermoplastic polymer composition;
- a step for mixing at least one amount of said polymer composition and at least one
amount of said metallic powder;
wherein;
- said powder of said step for preparing the powder, is formed by particles having
an average size of less than 0.5 micron;
- said polymer composition of said step for preparing at least one thermoplastic polymer
composition, is obtained from elastomeric thermoplastic polymers;
- said method comprises a step for introducing, into the plasticization chamber of
an extruder, said amount of said polymer composition in a percentage by weight ranging
between 70 and 5% and said amount of said metallic powder in a percentage by weight
ranging between 30 and 95%;
- said step for mixing is a thorough mixing at a temperature of between 120 and 220°C
said amount of polymer composition in the liquid state and said amount of metallic
powder by means of at least one screw provided with conveying and mixing segments;
- said procedure comprises moreover:
a step for extruding the mixture thus obtained resulting in an intermediate product
with a precious metal content and in the form of a bead and a step for forming the
ornamental article from said intermediate product.
- said precious material having an elongation at break in the range of 200-800% and
hardness of between 50 Shore A and 70 Shore D;
2. Method according to Claim 1, characterized in that it comprises a step for separating said bead into granules so as to form a granular
intermediate product, in particular with the granules in the form of prismatic, spherical
or cylindrical elements.
3. Method according to Claim 1, in which introduction of said thermoplastic composition
inside said chamber is performed by means of a first gravimetric metering device.
4. Method according to Claim 1, in which said amount of metallic powder is introduced
by means of a gravimetric metering device inside said plasticization chamber where
said thermoplastic polymer composition is in the liquid state.
5. Method according to Claim 1, in which said amount of thermoplastic polymer composition
is introduced into said extruder in granular form.
6. Method according to Claim 2, in which said forming step envisages supplying said granular
intermediate product to an injection moulding, intrusion moulding or compression moulding
press operating at temperatures of between 120 and 220°C.
7. Method according to Claim 2, in which said forming step envisages supplying said granular
intermediate product to an extrusion machine operating at temperatures of between
120 and 220°C.
8. Method according to any one of the preceding claims, in which said forming step envisages
supplying a hot-cylinder calendering machine.
9. Method according to Claim 8, in which said forming step produces an ornamental article
of jewellery or an accessory or an insert for products in the clock and watch-making,
spectacles, clothing, footwear and/or leatherwear sector, in view of the fact these
precious materials, precisely because they are elastic and resistant, at suitable
thicknesses, can be stitched.
10. Precious material for ornamental articles that comprises a metallic composition formed
by one or more precious metals present in an alloy, in combination or individually
and a thermoplastic polymer composition binding said precious metals within the precious
material, wherein;
- said precious metals have an average size of less than 0.5 micron and with an overall
content by weight in the range of between 30 and 95%;
- said thermoplastic polymer composition has an overall content by weight in the range
of between 70 and 5%;
- said metallic and polymer compositions have in an alloy a homogeneity resulting
from mixing in an extruder;
- said polymer composition comprising thermoplastic elastomeric polymers obtained
from polycondensation and chosen from the group comprising: thermoplastic polyurethanes,
copolyesters and copolyamides;
- said alloy has an elongation at break in the range of 200-800% and hardness of between
50 Shore A and 70 Shore D.
11. Precious material for ornamental articles according to Claim 10, in which said thermoplastic
polyurethanes comprise aliphatic isocyanates, carbonate ester of the medical type
with a molecular weight of between 400 and 4000, and chain extenders with a molecular
weight of between 50 and 400, in suitable and selected molar ratios.
12. Precious material for ornamental articles according to Claim 11, in which said thermoplastic
polymers (polyurethanes, copolyesters and copolyamides) may be further elastomerized
with compatibilized styrene block resins and/or with other known elastomerizing agents
such as nitrile and butadiene resins.
13. Precious material for ornamental articles according to Claim 10, in which said precious
metals are chosen from within the group containing: gold, silver, platinum or alloys
thereof.
14. Precious material for ornamental articles according to Claim 10, characterized in that it comprises an additive with an anti-microbial action, preferably consisting of
a solution of 2-octyl-2H-isothiazol-3-one and Triclosan, which is known by the tradename
of Sanitized™, and is present in a percentage amount varying from 0.3 to 1% by weight.
1. Verfahren zur Herstellung eines edlen Materials für Ziergegenstände, das folgendes
aufweist:
- einen Schritt zur Herstellung mindestens eines Pulvers von einem oder mehreren Edelmetallen,
die in einer Legierung einzeln oder in Kombination vorhanden sind;
- einen Schritt zur Herstellung mindestens einer thermoplastischen Polymerzusammensetzung;
- einen Schritt zum Vermischen mindestens einer Menge der Polymerzusammensetzung und
mindestens einer Menge des Metallpulvers;
wobei
- das Pulver aus dem Schritt zur Herstellung des Pulvers aus Partikeln mit einer Durchschnittsgröße
von weniger als 0,5 Mikron gebildet ist;
- die Polymerzusammensetzung des Schrittes zur Herstellung mindestens einer thermoplastischen
Polymerzusammensetzung aus elastomeren, thermoplastischen Polymeren hergestellt ist;
- das Verfahren einen Schritt zur Einführung der Menge der Polymerzusammensetzung
und der Menge an Metallpulver in die Plastifizierungskammer eines Extruders aufweist,
wobei die Menge der Polymerzusammensetzung in Gewichtsprozent zwischen 70 und 5% liegt
und die Menge an Metallpulver in Gewichtsprozent zwischen 30 und 95% liegt;
- es sich bei dem Schritt des Vermischens um ein gründliches Vermischen der Polymerzusammensetzung
im flüssigen Zustand und der Menge des Metallpulvers mittels mindestes einer Schnecke
mit Förder- und Mischsegmenten bei einer Temperatur zwischen 120 und 220 °C handelt;
- das Verfahren darüber hinaus folgendes aufweist:
einen Schritt zum Extrudieren des auf diese Weise hergestellten Gemisches, der zu
einem Zwischenprodukt in Form von Perlen mit einem Gehalt an Edelmetall führt, und
einen Schritt zur Herstellung des Ziergegenstandes aus dem Zwischenprodukt;
- wobei das edle Material eine Bruchdehnung im Bereich zwischen 200 und 800% und eine
Härte zwischen 50 Shore A und 70 Shore D aufweist;
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass es einen Schritt zur Trennung der Perlen in Körnchen oder Granulat aufweist, so dass
ein granuläres Zwischenprodukt gebildet wird, insbesondere Granulat in Form von prismatischen,
sphärischen oder zylindrischen Elementen.
3. Verfahren nach Anspruch 1, wobei die Einführung der thermoplastischen Zusammensetzung
in die Kammer mittels einer ersten gravimetrischen Messvorrichtung durchgeführt wird.
4. Verfahren nach Anspruch 1, wobei die Menge an Metallpulver mittels einer gravimetrischen
Messvorrichtung in die Plastifizierungskammer eingeführt wird, in der sich die thermoplastische
Polymerzusammensetzung im flüssigen Zustand befindet.
5. Verfahren nach Anspruch 1, wobei die Menge der thermoplastischen Polymerzusammensetzung
in granulärer Form in den Extruder eingeführt wird.
6. Verfahren nach Anspruch 2, wobei in dem Herstellungsschritt vorgesehen ist, dass das
granuläre Zwischenprodukt einer Spritzgießpresse, Fließgusspresse oder Formteilpresse
zugeführt wird, die bei Temperaturen zwischen 120 und 220 °C arbeitet.
7. Verfahren nach Anspruch 2, wobei in dem Herstellungsschritt vorgesehen ist, dass das
granuläre Zwischenprodukt einer Extrusionsmaschine zugeführt wird, die bei Temperaturen
zwischen 120 und 220 °C arbeitet.
8. Verfahren nach einem der vorhergehenden Ansprüche, wobei in dem Herstellungsschritt
vorgesehen ist, dass ein Heißkalander bereitgestellt wird.
9. Verfahren nach Anspruch 8, wobei in dem Herstellungsschritt ein Schmuckgegenstand
oder Zubehör oder ein Einsatzstück für Produkte bei der Uhrenherstellung, für Brillen,
Kleidung, Schuhe und/oder Lederwaren hergestellt werden, insbesondere da diese edlen
Materialien aufgrund ihrer elastischen und widerstandsfähigen Eigenschaften bei entsprechender
Stärke eingenäht oder eingeheftet werden können.
10. Edles Material für Ziergegenstände, das eine Metallzusammensetzung aufweist, die aus
einem Edelmetall oder mehreren Edelmetallen hergestellt ist, die in einer Legierung
in Kombination oder einzeln vorhanden sind, und eine thermoplastische Polymerzusammensetzung,
die die Edelmetalle in dem edlen Material bindet, wobei:
- die Edelmetalle eine durchschnittliche Größe von weniger als 0,5 Mikron aufweisen
und Gesamtgewichtsprozente in der Größenordnung zwischen 30 und 95%;
- die thermoplastische Polymerzusammensetzung Gesamtgewichtsprozente in der Größenordnung
zwischen 70 und 5% aufweist;
- die Metallzusammensetzung und die Polymerzusammensetzung in einer Legierung eine
Homogenität aufweisen, die aus dem Vermischen in einem Extruder resultiert;
- die Polymerzusammensetzung thermoplastische, elastische Polymere aufweist, die durch
Polykondensation hergestellt werden, und aus der Gruppe ausgewählt werden, die thermoplastische Polyurethane, Copolyester und Copolyamide aufweist;
- die Legierung eine Bruchdehnung im Bereich zwischen 200 und 800% und eine Härte
zwischen 50 Shore A und 70 Shore D aufweist.
11. Edles Material für Ziergegenstände nach Anspruch 10, wobei die thermoplastischen Polyurethane
aliphatische Isocyanate, medizinisches Carbonat-Ester mit einem Molekulargewicht zwischen
400 und 4000 und Streckmittel (chain extender) mit einem Molekulargewicht zwischen
50 und 400 in geeigneten, ausgewählten Molverhältnissen aufweisen.
12. Edles Material für Ziergegenstände gemäß Anspruch 11, wobei die thermoplastischen
Polymere (Polyurethane, Copolyester und Copolyamide) mit kompatibilisierten Styrol-Block-Harzen
und / oder mit anderen bekannten elastomerisierenden Stoffen wie Nitril-Harz und Butadien-Harz
weiter elastomerisiert werden können.
13. Edles Material für Ziergegenstände gemäß Anspruch 10, bei dem die Edelmetalle aus
der Gruppe ausgewählt werden, die Gold, Silber, Platin oder Legierungen davon enthält.
14. Edles Material für Ziergegenstände gemäß Anspruch 10, dadurch gekennzeichnet, dass es einen Zusatzstoff mit antimikrobialer Wirkung besitzt, der vorzugsweise aus einer
Lösung aus 2-Octyl-2H-Isothiazol-3-one und Triclosan besteht, und in Gewichtsprozenten
zwischen 0,3 und 1% vorhanden ist.
1. Procédé de fabrication d'un matériau précieux pour des articles ornementaux, qui comprend
:
- une étape de préparation d'au moins une poudre d'un ou de plusieurs métaux précieux
présents individuellement, ou dans un alliage, ou en combinaison ;
- une étape de préparation d'au moins une composition polymère thermoplastique ;
- une étape de mélange d'au moins une quantité de ladite composition polymère et d'au
moins une quantité de ladite poudre métallique ;
dans lequel :
- ladite poudre de ladite étape de préparation de la poudre est formée par des particules
ayant une dimension moyenne inférieure à 0,5 micron ;
- ladite composition polymère de ladite étape de préparation d'au moins une composition
polymère thermoplastique est obtenue à partir de polymères thermoplastiques élastomères
;
- ledit procédé comprend une étape d'introduction, dans la chambre de plastification
d'une extrudeuse, de ladite quantité de ladite composition polymère dans un pourcentage
en poids entre 70 et 5% et de ladite quantité de ladite poudre métallique dans un
pourcentage en poids entre 30 et 95% ;
- ladite étape de mélange est un mélange intime à une température entre 120 et 220°C
de ladite quantité de composition polymère dans l'état liquide et de ladite quantité
de poudre métallique au moyen d'au moins une vis comportant des segments de transport
et de mélange ;
- ledit procédé comprenant en outre :
une étape d'extrusion du mélange ainsi obtenu, conduisant à un produit intermédiaire
ayant une teneur en métal précieux et sous la forme d'une perle et une étape de façonnage
de l'article ornemental à partir dudit produit intermédiaire ;
- ledit matériau précieux ayant un allongement à la rupture dans la plage de 200-800%
et une dureté entre 50 Shore A et 70 Shore D.
2. Procédé selon la revendication 1, caractérisé par le fait qu'il comprend une étape de séparation de ladite perle en granules de façon à former
un produit intermédiaire granulaire, en particulier avec les granules sous la forme
d'éléments prismatiques, sphériques ou cylindriques.
3. Procédé selon la revendication 1, dans lequel l'introduction de ladite composition
thermoplastique à l'intérieur de ladite chambre est effectuée au moyen d'un premier
dispositif de dosage gravimétrique.
4. Procédé selon la revendication 1, dans lequel ladite quantité de poudre métallique
est introduite au moyen d'un dispositif de dosage gravimétrique à l'intérieur de ladite
chambre de plastification où ladite composition polymère thermoplastique se trouve
dans l'état liquide.
5. Procédé selon la revendication 1, dans lequel ladite quantité de composition polymère
thermoplastique est introduite dans ladite extrudeuse sous forme granulaire.
6. Procédé selon la revendication 2, dans lequel ladite étape de formage prévoit l'introduction
dudit produit intermédiaire granulaire dans une presse de moulage par injection, de
moulage par intrusion ou de moulage par compression, fonctionnant à des températures
entre 120 et 220°C.
7. Procédé selon la revendication 2, dans lequel ladite étape de façonnage prévoit l'introduction
dudit produit intermédiaire granulaire dans une machine d'extrusion fonctionnant à
des températures entre 120 et 220°C.
8. Procédé selon l'une quelconque des revendications précédentes, dans lequel ladite
étape de façonnage prévoit la disposition d'une machine de calandrage à cylindre chauffant.
9. Procédé selon la revendication 8, dans lequel ladite étape de façonnage produit un
article ornemental de bijouterie ou un accessoire ou un insert pour des produits dans
le secteur de l'horlogerie et de la fabrication des montres, des lunettes, des vêtements,
des articles chaussants et/ou des vêtements en cuir, compte tenu du fait que ces matériaux
précieux, précisément parce qu'ils sont élastiques et résistants, à des épaisseurs
appropriées, peuvent être cousus.
10. Matériau précieux pour articles ornementaux qui comprend une composition métallique
formée par un ou plusieurs métaux précieux présents dans un alliage, en combinaison
ou individuellement et une composition polymère thermoplastique liant lesdits métaux
précieux à l'intérieur dudit matériau précieux, dans lequel :
- lesdits métaux précieux ont une dimension moyenne inférieure à 0,5 micron et une
teneur globale en poids dans la plage entre 30 et 95% ;
- ladite composition polymère thermoplastique a une teneur globale en poids dans la
plage entre 70 et 5% ;
- lesdites compositions métallique et polymère ont dans un alliage une homogénéité
résultant du mélange dans une extrudeuse ;
- ladite composition polymère comprenant des polymères élastomères thermoplastiques
obtenus par polycondensation et étant choisis dans le groupe comprenant : les polyuréthanes
thermoplastiques, les copolyesters thermoplastiques et les copolyamides thermoplastiques
;
- ledit alliage a un allongement à la rupture se situant dans la plage de 200-800%
et une dureté entre 50 Shore A et 70 Shore D.
11. Matériau précieux pour articles ornementaux selon la revendication 10, dans lequel
lesdits polyuréthanes thermoplastiques comprennent des isocyanates aliphatiques, un
ester carbonate de type médical ayant une masse moléculaire entre 400 et 4000, et
des allongeurs de chaîne ayant une masse moléculaire entre 50 et 400, dans des rapports
molaires appropriés et choisis.
12. Matériau précieux pour articles ornementaux selon la revendication 11, dans lequel
lesdits polymères thermoplastiques (polyuréthanes, copolyesters et copolyamides) peuvent
être encore élastomérisés avec des résines à blocs de styrène compatibilisées et/ou
avec d'autres agents d'élastomérisation connus tels que les résines de nitrile et
de butadiène.
13. Matériau précieux pour articles ornementaux selon la revendication 10, dans lequel
lesdits métaux précieux sont choisis dans le groupe constitué par : l'or, l'argent,
le platine ou leurs alliages.
14. Matériau précieux pour articles ornementaux selon la revendication 10, caractérisé par le fait qu'il comprend un additif ayant une action anti-microbienne, de préférence consistant
en une solution de 2-octyl-2H-isothiazol-3-one et de Triclosan, qui est connu sous
la marque de fabrique Sanitized™ et est présent dans une quantité en pourcentage variant de 0,3 à 1% en poids.