EP2510133B1 - Method for preparing a metallized polymer substrate - Google Patents

Description

TECHNICAL AREA

The invention belongs to the technical field of surface coatings and, more particularly, to the technical field of metallization of surfaces.

Thus, the present invention relates to a simplified metallization process using polymer substrates.

STATE OF THE PRIOR ART

In general, the metallization consists in coating the surface of a part with a thin layer of metal.

The metallization of a plastic part is particularly used in areas such as automobiles and boats where some accessories (co) polymer are coated with chromium; the electronics industry, household appliances and lighting fixtures; cosmetics and fashion accessories; optics and watchmaking; etc. There is therefore a great interest in the development of a metallization process of a plastic surface and, more generally, polymers.

The metallization of polymers is a process developed for more than fifty years. She involves alternative techniques to those used for conductive substrates.

Currently, the metallization of the polymers is generally carried out in 3 steps.

The ^1st step is a surface modification step which provides, firstly, a surface roughness in order to improve the adhesion of the metal layer by mechanical anchoring.

This modification also makes it possible to increase the wettability of the polymer surface, in particular by adding hydrophilic groups generally incorporating oxygen or nitrogen in order to facilitate activation of the surface. Indeed, it is necessary that the polymer has groups promoting the adsorption of the activating metal agent.

For example, if the metal agent is palladium, chemisorption thereof is only possible on nitrogen elements [1]. Whatever the pretreatment, roughness and CO and / or CN bonding to the surface of the polymer to be metallized are mandatory.

The 2 ^nd step is a surface activation step of depositing metal particles on the surface of the modified polymer. These particles subsequently play the role of catalyst for the metallization. Thus, it is necessary to maintain on the surface of the polymer metal cations which will subsequently be reduced.

The last step uses a metallization bath in which the activated polymers are immersed. In this bath, metal growth is catalyzed by the metal particles deposited in the previous step. The metallization bath is a stable solution containing at least one metal cation and its complexing agent, a reducing agent and a stabilizer, generally in an alkaline medium.

Processes used in particular at the industrial level consisting of oxidizing the surface to be metallized and then adsorbing palladium on the latter via the tin / palladium colloid, which corresponds to the activation step. Following the latter, an acceleration step is implemented, to remove the tin and thus promote the activity of the precursor of the metal layer which is, in this case, palladium. Traces of tin can, in fact, induce metal growth in unwanted places. The acceleration step is followed by a step in the presence of a metallization bath as defined above.

This process is described in particular in the patent application CA 1 203 720 [2] . However, the process that is the subject of this application does not exhibit a Fenton type oxidation in the presence of the precursors of the metallic material. Indeed, the latter is not present during the step using hydrogen peroxide.

Given the diversity of the fields in which the metallization of polymers and in particular plastics is used and economic stakes, there is a real need for a simplified metallization process and therefore at a lower cost compared to processes currently used. used.

STATEMENT OF THE INVENTION

The present invention makes it possible to meet this expectation and to solve the technical problems of metallization processes of the state of the art.

In fact, the work of the inventors has made it possible to develop a metallization process in which several steps of the conventional metallization processes of the polymers are eliminated since the process of the invention consists in depositing and maintaining metal cations on the surface of the metal. a polymer at the same time as its surface oxidation.

1. a) soumettre ladite surface à un traitement oxydant par réaction chimique de type Fenton en présence d'au moins un précurseur dudit matériau métallique ;
2. b) transformer ledit précurseur en ledit matériau métallique

ledit traitement oxydant de ladite étape (a) consistant à mettre en contact ladite surface du substrat avec une solution contenant au moins un précurseur du matériau métallique et un composé de formule ROOR dans laquelle R représente un hydrogène, un groupe alkyle comprenant de 1 à 15 atomes de carbone, un groupe acyle -COR' avec R' représentant un groupe alkyle comprenant de 1 à 15 atomes de carbone ou un groupe aroyle -COAr avec Ar représentant un groupe aromatique comprenant de 6 à 15 atomes de carbone.More particularly, the present invention relates to a method of coating a surface of a (co) polymer substrate with a metallic material comprising the successive steps of:

1. a) subjecting said surface to an oxidizing treatment by Fenton-type chemical reaction in the presence of at least one precursor of said metallic material;
2. b) converting said precursor into said metallic material

said oxidative treatment of said step (a) of contacting said surface of the substrate with a solution containing at least one precursor of the metallic material and a compound of formula ROOR wherein R represents a hydrogen, an alkyl group comprising from 1 to 15 carbon atoms, an acyl group -COR 'with R' representing an alkyl group comprising from 1 to 15 carbon atoms or an aroyl group -COAr with Ar representing an aromatic group comprising from 6 to 15 carbon atoms.

For the purposes of the present invention, the term "metal-material coating" means a substrate coated on the surface with a thin layer, typically from a few nanometers to several microns, of a metal and / or a metal oxide. This thin layer may cover all or part of the surface of the substrate. The thus coated substrate may be called a "metallized substrate".

Among the metallized substrates, it is possible to distinguish the substrates metallized only by a metal or only by a metal oxide, substrates metallized by the two types of metal entities.

The substrate according to the present invention can have any size and shape. Indeed, the size of the substrate used in the context of the present invention may be nanometric, micrometric, millimetric or metric. Thus, the present invention applies, as non-limiting examples, to a substrate that can be chosen from the group consisting of a nanoparticle, a microparticle, a button, a cosmetic product cap, an electronic element, a handle door, an electrical appliance, glasses, a decorative object such as a luminaire, a bodywork element, etc.

By "surface of a substrate (co) polymer" means not only a substrate (co) polymer but also a substrate of which only the surface is in (co) polymer, the rest of the substrate can be in any material .

By "(co) polymer" is meant in the context of the present invention a substrate or a surface consisting essentially of a single (co) polymer or several (co) polymers.

By "essentially constituted" is meant in the context of the present invention a substrate or a surface of which at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least less 95% and / or at least 98% of the constituents expressed by weight are one (or more) (co) polymer (s).

Advantageously, the substrate or the surface of the substrate consists solely of one (or more) (co) polymer (s).

Alternatively, the substrate or substrate surface comprises, in addition to one (or more) (co) polymer (s), at least one member selected from the group consisting of fillers, plasticizers and additives. This (or these) element (s) additional (s) is (are) advantageously incorporated (s) and / or dispersed (s) in the polymeric material.

As a reminder, a plastic or plastic material is formed (e) of at least one (co) polymer advantageously having a degree of polymerization greater than 3000 and at least one additive. Therefore, the substrate or surface of the polymer substrate used in the context of the present invention comprises substrates or substrate surfaces of plastic or plastic.

Mineral fillers such as silica, talc, glass or organic fibers or beads such as cereal flour or cellulose pulp are generally used to reduce the cost and improve certain properties such as the mechanical properties of the polymeric material. The additives are mainly used to improve a specific property of the polymer material, said property possibly being crosslinking, slipping, resistance to degradation, fire and / or bacterial and fungal attacks.

Any natural, artificial, synthetic, thermoplastic, thermosetting, thermostable, elastomeric, linear (i.e. one-dimensional, linear or branched) and / or three-dimensional polymer is usable within the scope of the present invention. As non-limiting examples of natural polymers, mention may be made of sugars.

• une polyoléfine telle qu'un polyéthylène, un polypropylène, un copolymère éthylène/propylène, un polybutylène, un polyméthylpentène, un copolymère éthylène/acétate vinylique, un copolymère éthylène/alcool vinylique, un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polyester tel qu'un poyéthylène téréphthalate éventuellement modifié par du glycol, un polybutylène téréphthalate, un polylactide, un polycarbonate, un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polyéther tel qu'un poly(oxyméthylène), un poly(oxyéthylène), un poly(oxypropylène), un poly(phénylène éther), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polymère vinylique tel qu'un poly(chlorure de vinyle) éventuellement chloré, un poly(alcool vinylique), un poly(acétate de vinyle), un poly(acétal de vinyle), un poly(formal de vinyle), un poly(fluorure de vinyle), un poly(chlorure de vinyle/acétate de vinyle), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polymère vinylidénique tel qu'un poly(chlorure de vinylidène), un poly(fluorure de vinylidène), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polymère styrénique tel qu'un polystyrène, un poly(styrène/butadiène), un poly(acrylonitrile/ butadiène/styrène), un poly(acrylonitrile/styrène), un poly(acrylonitrile/éthylène/propylène/styrène), un poly(acrylonitrile/styrène/acrylate), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polymère (méth)acrylique tel qu'un polyacrylonitrile, un poly(acrylate de méthyle), un poly(méthacrylate de méthyle), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• une polyamide tel qu'un poly(caprolactame), un poly(hexaméthylène adipamide), un poly(lauroamide), un polyéther-bloc-amide, un poly(métaxylylène adipamide), un poly(métaphénylène isophtalamide), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polymère fluoré (ou polyfluoréthène) tel qu'un polytétrafluoroéthylène, un polychlorotrifluoroéthylène, un poly(éthylène/propylène) perfluoré, un poly(fluorure de vinylidène), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polymère cellulosique tel qu'un acétate de cellulose, un nitrate de cellulose, une méthylcellulose, un carboxyméthylcellulose, un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un poly(arylènesulfone) tel qu'un polysulfone, un polyéthersulfone, un polyarylsulfone, un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• un polysulfure tel que du poly(sulfure de phénylène) ;
• un poly(aryléther)cétone tel qu'un poly(éther cétone), un poly(éther éther cétone), un poly(éther cétone cétone), un(e) de leurs copolymères, de leurs mélanges et de leurs combinaisons ;
• une polyamide-imide ;
• une poly(éther)imide ;
• une polybenzimidazole ;
• un poly(indène/coumarone) ;
• un poly(paraxylylène) ;
• un de leurs copolymères, un de leurs mélanges et une de leurs combinaisons.

Advantageously, the polymer used in the context of the present invention is a thermoplastic (co) polymer selected from the group consisting of

• a polyolefin such as polyethylene, polypropylene, an ethylene / propylene copolymer, a polybutylene, a polymethylpentene, an ethylene / vinyl acetate copolymer, an ethylene / vinyl alcohol copolymer, a copolymer thereof, a mixture thereof and a their combinations;
• a polyester such as polyethylene terephthalate optionally modified with glycol, a polybutylene terephthalate, a polylactide, a polycarbonate, a copolymer thereof, mixtures thereof and combinations thereof;
• a polyether such as poly (oxymethylene), poly (oxyethylene), poly (oxypropylene), poly (phenylene ether), a copolymer thereof, mixtures thereof and combinations thereof;
• a vinyl polymer such as optionally chlorinated polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetal, polyvinyl formal, poly vinyl fluoride), a poly (chloride of vinyl / vinyl acetate), one of their copolymers, blends and combinations;
• a vinylidene polymer such as a polyvinylidene chloride, a polyvinylidene fluoride, a copolymer thereof, mixtures thereof and combinations thereof;
• a styrenic polymer such as polystyrene, poly (styrene / butadiene), poly (acrylonitrile / butadiene / styrene), poly (acrylonitrile / styrene), poly (acrylonitrile / ethylene / propylene / styrene), poly ( acrylonitrile / styrene / acrylate), one of their copolymers, blends and combinations thereof;
• a (meth) acrylic polymer such as polyacrylonitrile, poly (methyl acrylate), poly (methyl methacrylate), a copolymer thereof, mixtures thereof and combinations thereof;
• a polyamide such as a poly (caprolactam), a poly (hexamethylene adipamide), a poly (lauroamide), a polyether-block-amide, a poly (metaxylylene adipamide), a poly (metaphenylene isophthalamide), a their copolymers, blends and combinations;
• a fluorinated polymer (or polyfluoroethene) such as polytetrafluoroethylene, polychlorotrifluoroethylene, perfluoro poly (ethylene / propylene), polyvinylidene fluoride, a copolymer thereof, mixtures thereof and combinations thereof;
• a cellulosic polymer such as cellulose acetate, cellulose nitrate, methylcellulose, carboxymethylcellulose, a copolymer thereof, mixtures thereof and combinations thereof;
• poly (arylenesulfone) such as polysulfone, polyethersulfone, polyarylsulfone, a copolymer thereof, mixtures thereof and combinations thereof;
• a polysulfide such as polyphenylene sulfide;
• a poly (aryl ether) ketone such as a poly (ether ketone), a poly (ether ether ketone), a poly (ether ketone ketone), a copolymer thereof, mixtures thereof and combinations thereof;
• a polyamide-imide;
• a poly (ether) imide;
• a polybenzimidazole;
• a poly (indene / coumarone);
• poly (paraxylylene);
• one of their copolymers, one of their mixtures and one of their combinations.

Alternatively, the (co) polymer used in the context of the present invention is a thermosetting (co) polymer selected from the group consisting of an aminoplast such as urea-formaldehyde, melanin-formaldehyde, melanin-formaldehyde / polyesters, one of their copolymers, blends and combinations thereof; polyurethane; unsaturated polyester; a polysiloxane; a resin formophenolic, epoxy, allylic or vinylester; an alkyd; polyurea; a polyisocyanurate; a poly (bismaleimide); a polybenzimidazole; polydicyclopentadiene; one of their copolymers, one of their mixtures and one of their combinations.

Additional information on the polymers that can be used in the context of the present invention can be found in the article by Naudin, 1995 [3].

By way of nonlimiting examples of (co) polymer that may be used in the context of the present invention, mention may be made of acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene styrene / polycarbonate (ABS / PC), polyamide (PA ) such as nylon, polyamine, polyacrylic acid, polyaniline and polyethylene terephthalate (PET).

Prior to step (a) of the process according to the invention, the substrate to be metallized has no precursor of the metallic material adsorbed on the surface.

By "oxidizing treatment" is meant in the context of the present invention a treatment for oxidizing the surface of the substrate used. This oxidation modifies the surface of the substrate, in particular by fixing and / or introducing therein groups that are rich in oxygen and in particular polar and / or hydrophilic groups such as carboxylic (-COOH), hydroxyl (-OH) and alkoxyl groups. (-OR) with R as defined below), carbonyl (-C = O), percarboxylic (-CO-OH) and sometimes amide (-CONH). Such an oxidative treatment is also susceptible to increase the hydrophilicity of the surface of the substrate used.

This treatment relies on the use of various reagents to create on the surface of the (co) polymer constituting the surface of the substrate and / or the substrate, a surface oxidation allowing a better grip and / or a better maintenance on the surface of the substrate precursor of a metallic material present during the oxidizing treatment. This attachment and / or this maintenance implements a chelation (or complexation) between the precursor of a metallic material and groups present on the oxidized surface. All or part of the precursor of the metallic material remains in particular on the surface of the (co) polymer and can be reduced thereafter.

Advantageously, step (a) of the process according to the present invention is carried out at a temperature below 60 ° C., in particular between 5 ° C. and 50 ° C. and, in particular, between 10 ° C. and 40 ° C. vs. Step (a) according to the invention is carried out, in a particular embodiment, at room temperature. By "ambient temperature" is meant a temperature of 20 ° C ± 5 ° C.

The oxidizing treatment used during step (a) is based on the chemical reaction of Fenton (1894). This oxidizing treatment can therefore be designated oxidative treatment by Fenton-type chemical reaction. As a reminder, the chemical reaction of Fenton consists of an acidic oxidation of hydrogen peroxide by ferrous ions represented by the following reaction scheme:

Fe ²⁺ + H ₂ O ₂ → Fe ³⁺ + ^· OH + OH ^-

This reaction generates hydroxyl radicals ( ^· OH) which are very reactive especially towards the plastic surfaces, the ferrous ions acting as a precursor of the metallic material.

The generalized Fenton chemical reaction applied to the oxidizing treatment of step (a) of the process of the present invention comprises contacting said surface of the substrate with a solution containing at least one precursor of the metallic material and a compound of formula ROOR wherein R represents a hydrogen, an alkyl group comprising from 1 to 15 carbon atoms, an acyl group -COR 'with R' representing an alkyl group comprising from 1 to 15 carbon atoms or an aroyl group -COAr with Ar representing a aromatic group comprising from 6 to 15 carbon atoms.

By "alkyl group comprising 1 to 15 carbon atoms" is meant an optionally substituted linear, branched or cyclic alkyl group comprising from 1 to 15 carbon atoms, especially from 1 to 10 carbon atoms, and in particular , from 2 to 6 carbon atoms and optionally a heteroatom such as N, O, F, Cl, P, Si, Br or S.

By "aromatic group comprising from 6 to 15 carbon atoms" is meant, in the context of the present invention, an optionally substituted aromatic or heteroaromatic group consisting of one or more aromatic rings or heteroaromatic atoms each containing from 3 to 10 atoms, the heteroatom (s) possibly being N, O, P or S.

By "substituted" is meant, in the context of the present invention, an alkyl or aromatic group, mono- or poly-substituted, with a linear or branched alkyl group comprising from 1 to 4 carbon atoms, by a group amine, with a carboxylic group and / or with a nitro group.

OR radicals with R as defined above are obtained by cleavage of the ROOR peroxide by the precursor of the metallic material. The reaction in step (a) of the process of the present invention can be represented by the following reaction scheme:

Z ^{n +} + ROOR → Z ^{(n + 1) +} + ^. OR + OR ^-

with Z representing the precursor of the metallic material and n representing an integer between 1 and 7 and in particular between 1 and 5. The integer n is advantageously chosen from the group consisting of 1, 2, 3, 4 and 5.

The precursor (s) of the metallic material used during step (a) of the process according to the invention plays (s) a role of catalyst (s) for the metal growth and therefore the metallization of the surface of the substrate. The precursor (s) of the metallic material is (are) advantageously one (or more) metal cation (s), in particular chosen from the noble metals of group IB or group VIII. More particularly, the precursor (s) of the metallic material is (are) chosen from the group formed by the ions of copper, silver, gold, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium and platinum.

The precursors of the metallic material are present in the solution comprising at least one precursor of the metallic material and a compound of formula ROOR at a concentration of between 0.05 and 5 M, in particular between 0.1 and 3 M and, in particular, between 0.5 and 2.5 M. The solution comprising at least one precursor of the metallic material and a compound of formula ROOR additionally comprises counterions such as tetrafluoroborate, sulphate, bromide, fluoride, iodide, nitrate, phosphate or chloride. .

The compound of formula ROOR is present in the solution comprising at least one precursor of the metallic material and. a compound of formula ROOR at a concentration of between 5 × 10 ^-4 M and 5 M, especially between 0.1 and 3 M and in particular between 0.5 and 2.5 M.

The solution comprising at least one precursor of the metallic material and a compound of formula ROOR is advantageously an acidic solution. By "acid solution" is meant a solution whose pH is less than 7, especially between 2 and 4 and, in particular, of the order of 3 (i.e. 3 ± 0.5). This solution also comprises sulfuric acid and in particular at a concentration of between 0.05 and 50 mM, in particular between 0.1 and 10 mM and, more particularly, of the order of 1 mM (ie 1 ± 0.25 mM).

The duration of the Fenton-type chemical reaction treatment may be variable. As examples non-limiting, this duration is advantageously between 5 min and 5 h, in particular between 10 min and 3 h, in particular between 15 min and 2 h and, more particularly, of the order of 25 min (ie 25 ± 5 min ).

It may be necessary, after the oxidizing treatment by Fenton-type chemical reaction, to add other precursors of the metallic material and this by putting the surface of the substrate and / or the substrate in contact with a chelation bath under well-controlled conditions. known to those skilled in the art.

As a variant, the precursors of the metallic material are only provided by the solution used during the Fenton reaction i.e. the solution implemented during step (a) of the process of the invention.

In the context of the present invention, the Fenton reaction is used to oxidize the surface of the substrate to be metallized but also to adsorb the metal cations acting thereafter as precursors of the metal layer deposited by Electroless.

Step (b) of the process according to the present invention is a step well known to those skilled in the field of metallization of materials since it consists in transforming the precursor of the metallic material into said metallic material.

Any technique allowing such a transformation can be used in the context of the present invention.

• b₁) éventuellement réduire ledit précurseur dudit matériau métallique présent à la surface dudit substrat ;
• b₂) mettre en contact ledit précurseur éventuellement réduit suite à l'étape (b₁) dans une solution contenant au moins un ion du matériau métallique.

Advantageously, this transformation step has the successive sub-steps of

• b ₁ ) optionally reducing said precursor of said metal material present on the surface of said substrate;
• b ₂ ) contacting said precursor optionally reduced following step (b ₁ ) in a solution containing at least one ion of the metallic material.

Any technique for reducing the precursor of the metallic material can be used in the context of step (b ₁ ) of the process according to the present invention.

Advantageously, this reduction step is a chemical reduction in a single step. This preferred variant consists in bringing into contact the surface of the substrate on which the precursor (s) of the metallic material is (are) with a reducing solution S _R.

Advantageously, the reducing solution S _R is basic. The reducing solution S _R comprises a reducing agent, in particular chosen from the group consisting of sodium borohydride (NaBH ₄ ), dimethylamine borane (DMAB-H (CH ₃ ) ₂ NBH ₃ ) and hydrazine (N ₂ H ₄ ) .

When the reducing agent is NaBH ₄ , the pH of the reducing solution S _R is neutral or basic, whereas for DMAB the pH of the solution S _R is basic. When the solution S _R is basic, a solvent advantageously used is NaOH and in particular at a concentration between 10 ^-4 M and 5 M, especially between 0.05 and 1 M and, in particular, of the order of 0.1 M (ie 0.1 M ± 0.01 M).

The reducing agent is present in the reducing solution S _R at a concentration of between 10 ^-4 and 5 M, in particular between 0.01 and 1 M and, in particular, of the order of 0.3 M (ie 0, 3 M ± 0.05 M).

The reduction step (b ₁ ) can be carried out at a temperature between 20 ° C and 100 ° C, in particular between 30 ° C and 70 ° C and, in particular, of the order of 50 ° C (ie 50 ° C ± 5 ° C).

In addition, the reduction step (b ₁ ) can last between 30 sec and 1 h, in particular between 1 and 30 min and, in particular, between 2 and 20 min.

The precursors of the metallic material reduced following step (b ₁ ) of the process according to the invention mainly have an oxidation degree of 0. Thus, the metallization can then take place by immersion in a metallization bath and growth on the precursor particles at an oxidation degree of 0.

It should be noted that this reduction step (step (b ₁ )) may be optional. Indeed, in some cases, the precursor of the metallic material can be reduced during contacting with the solution containing at least one ion of the metallic material during step (b ₂ ) without a prior reduction step be necessary. Indeed, if the precursor of the metallic material has a higher oxidation-reduction potential than the metal deposited by Electroless, the precursor of the metallic material can be, initially, reduced upon contact with the ion of the metallic material before the metal growth is initiated.

Step (b ₂ ) therefore consists in bringing said reduced precursor into contact following step (b ₁ ) in a solution containing at least one ion of the metallic material. The solution containing an ion of the metal material hereinafter designated S _M corresponds to a metallization bath well known to those skilled in the art, just like its components.

By way of example, the solution containing at least one ion of the metallic material S _M implemented in step (b ₂ ) comprises ions of the metallic material, a complexing agent for the ions of the metallic material, a reducing agent and a pH regulator. Advantageously, said solution S _M is an aqueous solution. In addition, several metallization solutions are commercially available.

The ion (s) of the metallic material used in the context of the present invention may be any ion of a metallic material. The present invention relates more particularly to the ions of a transition metal. Advantageously, the ion (s) of the metallic material according to the invention is (are) chosen from the group consisting of Ag ⁺ , Ag ²⁺ , Ag ³⁺ , Au ⁺ , Au ³⁺ , Co ²⁺ , Cu ⁺ , Cu ²⁺ , Fe ²⁺ , Ni ²⁺ , Pd ⁺ , and Pt ⁺ .

In the solution S _M , the ion (s) of the metallic material is (are) associated with a counter-ion anionic. As anionic counterions that may be used, mention may be made of a chloride, a bromide, a fluoride, an iodide, a sulphate, a nitrate, a phosphate, an acetate and any organic or inorganic acid salt.

The complexing agent ions of the metallic material is necessary to compensate for the loss of solubility of these ions under the basic conditions used and avoid their precipitation. Such a complexing agent is in particular chosen from organic acids and their salts such as tartaric acid, EDTA or EDTP.

The reducing agent advantageously used may especially be formaldehyde, DMAB or H ₂ PO ₂ . Those skilled in the art know different ion pairs of the metallic material / reducing agent used in the context of the present invention. Similarly, depending on the particular couple chosen, those skilled in the art the pH and temperature conditions of the solution S _M to implement.

By way of example in a solution S _M containing copper ions, the reducing agent advantageously used under basic conditions is formaldehyde in an amount of between 0.1 and 5% (v / v) with respect to total volume of the solution S _M. By "basic conditions" is meant a solution whose pH is between 10 and 14 and in particular between 12 and 13, such a pH is reached using NaOH as a pH regulator.

By way of example in a solution S _M containing copper ions, the metallization step (b ₂ ) can be carried out at a temperature of between 20 ° C. and 80 ° C., in particular between 30 ° C. and 60 ° C. and, in particular, of the order of 40 ° C. (ie 40 ° C. ± 5 ° C.). ° C).

In addition, the metallization step (b ₂ ) can last between 1 min and 1 h, in particular between 5 and 45 min and, in particular, between 10 and 30 min.

The metallization of the surface of the substrate i.e. the presence of a thin layer of metallic material on the surface of the substrate is easily verifiable, typically, visually and in particular with the naked eye.

In the context of the present invention, prior to step (a) of the method, the surface of the substrate to be metallized may possibly undergo different pre-treatments. These pretreatments may be conventional treatments in the field of metallization of surfaces such as degreasing or polishing.

As a variant, the surface of the substrate may optionally be subjected, prior to step (a) of the process according to the invention, to a treatment capable of increasing its hydrophilicity and / or roughness, said treatment being chosen from the group consisting of a sandblasting, abrasion, chemical treatment with pickling bath, flame treatment, corona treatment and plasma treatment and combinations thereof.

Indeed, the processing implemented during step (a) does not bring any additional roughness to the surface of the substrate which can be verified by AFM measurement. Also, according to the initial roughness of the (Co) polymer constituting the surface of the substrate or the substrate, a pretreatment preceding step (a) to bring a surface roughness must be performed.

In addition, it may be necessary to increase the hydrophilicity of the (co) polymer constituting the surface of the substrate or the substrate to be treated. Some (co) polymers already have nitrogen or oxygen groups such as poly (acrylic acid), polyanilines and polyamides. If these oxygens or nitrogens are accessible on the surface of the substrate to be metallized, the step providing hydrophilicity is not mandatory.

Depending on the polymer, the surface roughness with or without hydrophilic function can be provided by mechanical pretreatment, chemical or dry and will, in some cases, accompanied by surface oxidation.

Mechanical pretreatment of the surface to be treated consists of sandblasting or abrasion with grains of larger or smaller size. It does not modify in any way the chemical composition of the surface and therefore does not oxidize the surface of the (co) polymer constituting the surface of the substrate or the substrate to be treated. In addition, it is not always effective and remains possible only in the case of substrates of adequate size such as substrates in the form of large flat parts.

A chemical pretreatment (acid / base) (or chemical treatment with pickling bath) is based on contacting the surface to be treated with a bath acid or basic pickling and is specific to the (co) polymers to be metallized. It brings surface roughness and very generally surface oxidation. In each case, etching, also called "satin", will degrade the surface (co) polymer constituting the surface of the substrate or the substrate to be treated by etching. This stripping follows the laws of the chemical reactivity of the polymer chains.

Indeed, this degradation causes a rupture of chains of (co) polymers on the surface, thereby causing their solubilization in order to reveal a roughness on the surface of the (co) polymer. By way of examples, an acid attack on polyamide-type polymers allows degradation of the organic material. In the same way, a basic attack allows the degradation and the dissolution of the polycarbonate contained in the surface in the ABS-PC increasing the surface roughness. These acid-base treatments provide roughness and oxidation.

As an example of a pickling bath, mention may be made of an acidic aqueous solution comprising at least one inorganic acid. Said inorganic acid is especially selected from the group consisting of chromic acid, sulfuric acid, nitric acid, hypochlorous acid and mixtures thereof. By "mixture" is meant a mixture of at least two different inorganic acids such as a mixture of chromic acid and sulfuric acid or a mixture of at least three different inorganic acids such as an acid mixture nitric acid, hypochlorous acid and sulfuric acid.

The chemical pre-treatment is advantageously carried out for a period of between 1 and 60 min, in particular between 2 and 30 min and, in particular, between 5 and 20 min and at a temperature of between 20 and 120 ° C, in particular between 40 and 110 ° C and in particular between 60 and 100 ° C.

The surface to be treated may also be subjected to a dry pretreatment. Such physicochemical treatments comprising a flame treatment, a corona treatment and a plasma treatment also have a double effect: i) the oxidation of chemical bonds on the surface and ii) the increase in roughness.

The flame treatment also known as "flaming" consists in exposing the surface of the substrate and / or the substrate to the action of a flame and in particular to the action of a stable and slightly oxidizing flame. The high temperatures of this treatment generate active species that can correspond to radicals, ions or excited molecules. The (co) polymer constituting the surface of the substrate and / or the substrate is oxidized to a thickness of about 4 to 9 mm. On the surface, functional groups of carboxylic type (-COOH), hydroxyl (-OH), carbonyl (-C = O), amine (-NH ₂ ), nitrile (-CN) and sometimes amide (-CONH) are fixed. A diffusion phenomenon is observed inside the polymer of chemical species resulting from its degradation. There is a real restructuring of the surface. These changes are result in an improvement of the wettability and roughness of the surface to be coated.

The flame is in particular disposed at a distance from the surface of the substrate and / or the substrate of between 0.1 and 20 cm, in particular between 0.3 and 10 cm and more particularly between 0.5 and 5 cm.

This flame is advantageously generated by a mixture of at least two gases, the first and second gases being respectively chosen from the group consisting of hydrogen, methane, ethane and propane and the group consisting of air , ozone and oxygen. The temperature of the flame thus obtained is between 500 and 1600 ° C, especially between 800 and 1400 ° C and, in particular, of the order of 1200 ° C (i.e. 1200 ± 100 ° C).

The duration of the flame treatment is between 0.01 and 10 sec, in particular between 0.015 and 1 sec, and in particular between 0.02 and 0.1 sec.

Corona treatment is also referred to as "corona treatment" or "corona discharge treatment" and involves exposing the surface of the substrate and / or the substrate to an ionization field created by passing an alternating current of high voltage between two electrodes distant a few mm and in particular 1 to 2 mm. Thus, an electrical discharge driven by the ionization of the medium surrounding a conductor occurs when the electric potential exceeds a critical value but the conditions do not allow the formation of an arc.

During this ionization, the emitted electrons are precipitated in the electric field and transmit their energy to the molecules of the medium surrounding the surface of the substrate and / or the substrate which is advantageously air or an inert gas optionally enriched with oxygen. This leads to dehydrogenation and chain failure of the substrate (or co) polymer (s) as well as spontaneous reactions with the chemical species present in the medium. The surface of the (co) polymer constituting the surface of the substrate and / or the substrate is oxidized.

Density be sitting corona discharge is advantageously between 10 to 500 W.min / m ^2, in particular from 20 to 400 W.min / m ² and, particularly, from 30 to 300 W.min / m ^2.

The duration of treatment with the corona effect is between 0.1 and 600 sec, especially between 1 and 120 sec, and in particular between 10 to 50 sec.

Plasma treatment involves exposing the surface of the solid support and / or the solid support to a plasma.

As a reminder, plasma is a gas in the ionized state, classically considered as a fourth state of matter. The energy required for the ionization of a gas is provided by means of an electromagnetic wave (radio frequency or microwave). Plasma is composed of neutral molecules, ions, electrons, radical species (chemically very active) and excited species that will react with the surface of materials. If the plasma gas contains Oxygen or nitrogen, these atoms will react instantly with the surface of the (co) polymer and create active sites there. The modification of the (co) polymers by the plasmas results in the formation of radicals and double bonds, by the crosslinking and the functionalization of the surface. Plasma treatment is usually limited to the extreme surface and the surface roughness provided is limited.

We distinguish the so-called "cold" plasmas and the so-called "hot" plasmas which are distinguished from each other with respect to the ionization rate of the species contained in the plasma. For so-called "cold" plasmas, the ionization rate of the reactive species is less than 10 ^-4 while for so-called "hot" plasmas it is greater than 10 ^-4 . The terms "hot" and "cold" come from the fact that the so-called "hot" plasma is much more energetic than the so-called "cold" plasma. In the case of a pretreatment in the context of the process according to the invention, a so-called "cold" plasma is more suitable. The plasma is advantageously generated by one (or more) plasma gas (s). In the case where the plasma gas is a mixture of at least two gases, the first and second gases are respectively selected from the group consisting of inert gases and the group consisting of air and oxygen.

The duration of the plasma treatment is between 1 sec and 5 min, especially between 10 to 60 sec and, in particular, between 20 and 40 sec.

In the context of the process according to the present invention, it may be necessary between two treatment steps; prior to step (a); between steps (a) and (b) or between steps (b ₁ ) and (b ₂ ) subjecting the surface of the substrate and / or substrate to rinsing or rinsing using identical or different rinsing solutions .

Any rinse solution known to those skilled in the art is usable. Advantageously, this rinsing solution is selected from water, distilled water, deionized water, MilliQ water, an aqueous solution containing a detergent such as TDF4 or sodium hydroxide including sodium hydroxide in a concentration of between 0.01 and 1 M. The rinsing solution, when it is brought into contact with the surface of the substrate or the substrate, can be agitated, in particular by using a stirrer, a magnetic bar, an ultrasound bath or a homogenizer. Each rinsing step can last from 1 to 30 min and in particular from 5 to 20 min.

The present invention finally relates to a substrate whose surface is coated with a metallic material that can be obtained by the method of the invention as previously defined.

Other features and advantages of the present invention will become apparent to those skilled in the art on reading the examples below given for illustrative and non-limiting, with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

• The Figure 1 presents the cyclic voltammetry diagram on a copper electroless electroless ABS plate according to the method of the present invention.
• The Figure 2 presents the cyclic voltammetry diagram on a electroless electroless metallized copper ABS-PC plate according to the method of the present invention.
• The Figure 3 presents the cyclic voltammetry diagram on a copper electroless plated AP plate according to the method of the present invention.
• The Figure 4 presents the cyclic voltammetry diagram on an electroless electroless metallized copper ABS plate according to the method of the present invention (Example II hereinafter).
• The Figure 5 presents the cyclic voltammetry diagram on an electroless electroless metallized copper ABS-PC plate according to the method of the present invention (Example III hereinafter).

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS I. Metallization via Fenton treatment of acrylonitrile butadiene styrene (ABS), acrylonitrile butadiene styrene / polycarbonate (ABS / PC) and polyamide (PA) plates .

This metallization process is carried out in 3 steps (Fenton Treatment / Reduction / Metallization electroless) and before treating the polymer, it should be prepared, degreased and cleaned.

I.1. Polishing

In a ^1st step, the plates are subjected to polishing to minimize edge effects and other defects introduced during the cutting of the plates.

I.2. Rinsing

In a 2 ^nd time, the plates are rinsed with a soap solution industrial TDF4 mixed with water (1 mL of TDF4 for 4 mL of H ₂ O MilliQ), under ultrasound for 10 min. The plates are then rinsed with MilliQ water, under ultrasound for 10 min.

I.3. Pretreatment of Fenton

Iron (II) sulfate (6.961 g, 0.1 mol) was solubilized in 50 mL of 10 ^-3 M sulfuric acid in water. In this solution, the polymer plates were immersed. 10 mL (0.124 mol) of 35% hydrogen peroxide in water was then added dropwise. After 25 min, the samples were rinsed with MilliQ water before being dried.

The results obtained for the contact angle measurements of a droplet of 2 μl of water deposited on the samples treated according to the treatment of Fenton ("After") or without treatment ("Virgin") are presented in Table 1. below. <i><b> Table 1 </ b>: Measuring the contact angles of a drop </ i> ABS ABS / PC PA Virgin 90 81.8 ° 63.2 ° After Fenton 0 to 14 ° 32.4 ° 0 to 15 °

The contact angle is clearly lowered. The surface has become very hydrophilic because of its oxidation.

The analysis of the IR spectra is presented in Table 2 below. <i><b> Table 2 </ b></i>:<i> IR bands that appeared after the oxidative treatment of Fenton on the samples </ i> Polymer plates ABS ABS / PC PA After Fenton 3600-3200 cm ^-1 3600-3100 cm ^-1 3600-3100 cm ^-1 1700-1640 cm ^-1 1700-1640 cm ^-1 1150-1100 cm ^-1 1150-1100 cm ^-1

The appearance of bands at 3600-3200 cm ^-1 and between 1150-1100 cm ^-1 is typical of the contribution of C-OH bonds. For ABS and ABS-PC, the band at 1700-1640 cm ^-1 could mean the appearance of amide groups originating from the oxidation of the nitrile groups of polyacrylonitrile. In the context of the polyamide, the bands 1150-1100 and 1700 are confused with the strips of the virgin polymer.

The XPS analysis of the ABS plate before / after treatment of Fenton shows a Fe ²⁺ / Fe ³⁺ ion supply and a strong oxidation of the surface by an oxygen supply. The atomic ratios with respect to the carbon signal are shown in Table 3 below. <i><b> Table 3 </ b>: Report of the intensities obtained at the XPS analysis of the different elements with respect to the electrons of the carbon layer 1s </ i> Intensity Report X / C1s Electrons ABS Virgin ABS Fenton C1s 1 1 O1s 0,028 1,130 N 1s 0.097 0.049 Fe 2p3 / 2 0 0.141 Fe 2p1 / 2 0 0.122 B 1s 0 0 S 2p 0 0.132

I.4. Reduction of ferric / ferrous ions

NaBH ₄ sodium borohydride (0.316 g, 0.8 X 10 ^-2 mol) is dissolved in 25 ml of a 0.1 M sodium hydroxide solution (NaOH). This solution is heated to 80 ° C. at room temperature. using a water bath and the samples are immersed in it. After 12 min, the samples were rinsed with MilliQ water before being dried.

IR analysis reveals the preservation of the oxidation obtained after Fenton with the bands at 3600-3100 cm ^-1 , and the bands 1700-1640 cm ^-1 , whatever the polymer.

The XPS analysis of the ABS plate before / after reduction shows a slight decrease of all elements except the appearance of bohr. According to the XPS spectra, it is in oxidized form and thus confirms the reduction of Fe ²⁺ / Fe ³⁺ ions by borohydride BH ₄ ^- . The iron is, in turn, oxidized in air and water before the XPS analysis and is in oxidized form. The atomic ratios with respect to the carbon signal are shown in Table 4 below. <i><b> Table 4 </ b>: Report of the intensities obtained in the XPS analysis of the different elements with respect to the electrons of the carbon layer 1s </ i> Intensity Report X / C1s Electrons ABS Fenton ABS Fenton + Reduction C1s 1 1 O1s 1,130 0.860 N 1s 0.049 0,027 Fe 2p3 / 2 0.141 0.124 Fe 2p1 / 2 0.122 0.108 B 1s 0 0.088 S 2p 0.132 0.116

I.5. Copper electroless metallization bath

The samples are immersed in the solution described in Table 5 below, heated to 40 ° C. in a water bath: <b><i> Table 5 </ i></b>:<i> Composition of copper plating bath </ i> Metallic bath Reagents m (g) for 100 mL C (g / l) CuSO ₄ , 7H ₂ O 0.5 5 Dissodium tartrate C ₄ H ₄ Na ₂ O ₆ 2.96 25 NaOH 0.5 7 Formaldehyde HCHO (37% in H ₂ O) 2.94 10 mL / L

After 15 min, the samples were rinsed with MilliQ water, under ultrasound for 10 min before being dried.

Infrared analysis reveals the disappearance of the peaks of the different polymers.

XPS analysis confirms the presence of a metallic copper layer (in its reduced form, Cu ⁰ ). The atomic ratios with respect to the carbon signal are shown in Table 6 below. <i><b> Table 6 </ b>: Report of the intensities obtained in the XPS analysis of the different elements with respect to the electrons of the 1s carbon layer </ i> Intensity Report X / C1s Electrons ABS Fenton + Reduction ABS after metallization C1s 1 1,000 O1s 0.860 0.501 N 1s 0,027 0,030 Fe 2p3 / 2 0.124 0 Fe 2p1 / 2 0.108 0 B 1s 0.088 0 S 2p 0.116 0 Cu 2p3 / 2 0 0.816 Cu 2p1 / 2 0 0.713

The copper layer is also visible to the eye. The presence of carbon, nitrogen and oxygen after metallization is due to the presence of organic impurities at the extreme surface of the metallized substrate. Oxygen can also come from the air oxidation of the copper layer prior to analysis.

I.6. Electroplating copper deposit

In order to confirm the presence of a metal layer, copper was deposited by electroplating. This technique is only possible in the presence of conductive substrates.

Thus the plates of ABS, PC-PC and PA having undergone a metallization with copper were used, in turn, like measuring electrode. The system Electrochemical set up consisted of a saturated KCl calomel reference electrode and a graphite counter electrode.

The electrodes were soaked in a solution of CuSO ₄ at 10 g / L, the initial potential was about 0.1 V.

A voltammetry cycle of up to -0.6 V was imposed on the system. During the voltage rise, the experiment was stopped at around -0.45 V ( Figures 1, 2 and 3 ).

This cycle showed the deposition of copper on the measuring electrode. Indeed, the current increased when the voltage decreased and the copper was deposited on the plates acting as measuring electrode. Copper reduction took place at the measuring electrode.

The confirmation of the copper deposit is also visual. Indeed, the copper layer deposited by electrochemistry has a slightly more homogeneous appearance.

II. Metallization via pretreatment with Fenton treatment of ABS plates.

This metallization process is carried out in 4 stages (Pretreatment Oxidizer / Fenton Treatment / Reduction / Electroless Metallization) and before treating the polymer, it is necessary to prepare it, degrease and clean.

II.1. Polishing

In a ^1st step, the plates are subjected to polishing to minimize edge effects and other defects introduced during the cutting of the plates.

II.2. Rinsing

In a 2 ^nd time, the plates were rinsed using an industrial soap solution TDF4 mixed with water (1 mL TDF4 4 mL of MilliQ H ₂ 0) under ultrasound for 10 min. The plates are then rinsed with MilliQ water, under ultrasound for 10 min.

II.3. Pretreatment acid

The plates are immersed for 10 min in a 60% nitric acid solution at a temperature of 60 ° C. The plates are then rinsed in a NaOH solution (0.1M) in ultrashons for 10 min and then in MilliQ water under ultrasound for 10 min.

The results obtained for the contact angle measurements of a droplet of 2 μl of water deposited on the samples treated according to the treatment of Fenton ("After") or without treatment ("Virgin") are presented in Table 7. below. <i><b> Table 7 </ b>: Measuring the contact angles of a drop </ i> ABS Virgin 90 After acid pretreatment 67 °

The contact angle is lowered. The surface has become more hydrophilic due to its oxidation and the surface roughness has increased.

The analysis of the IR spectra is presented in Table 8 below. <i><b> Table 8 </ b>: IR Bands Appeared After Acid Pretreatment </ i> Polymer plates ABS After acid treatment 3600-3200 cm ^-1 1660-1610 cm ^-1 1570-1530 cm ^-1 1320-1280 cm ^-1

The appearance of bands at 3600-3200 cm ^-1 and 1660-1610 cm ^-1 may be due to the presence of traces of water.

On the other hand, the bands at 1570-1530 cm ^-1 and at 1320-1280 cm ^-1 are characteristic of carbonyl groups, carboxylate type COO ^- . This confirms surface oxidation.

II.4. Pretreatment of Fenton

Iron (II) sulfate (6.961 g, 0.1 mol) was solubilized in 50 mL of 10 ^-3 M sulfuric acid in water. In this solution, the polymer plates were immersed. 10 mL (0.124 mol) of 35% hydrogen peroxide in water were then added, drip. After 25 min, the samples were rinsed with MilliQ water before being dried.

The results obtained for the contact angle measurements of a droplet of 2 μl of water deposited on the samples treated according to the Fenton treatment ("After Fenton") or before treatment ("After acid treatment") are presented in Table 9 below. <i><b> Table 9 </ b>: Measuring the contact angles of a drop </ i> ABS After acid treatment 67 ° After Fenton 0 to 5 °

The contact angle is clearly lowered. The surface has become very hydrophilic because of its oxidation.

The analysis of the IR spectra is presented in Table 10 below. <i><b> Table 10 </ b>: IR Bands Appeared After Fenton's Oxidative Treatment on Samples </ i> Polymer plates ABS After Fenton 3600-3200 cm ^-1 1700-1600 cm ^-1 1320-1280 cm ^-1 1150-1100 cm ^-1

The amplification of the 3600-3200 cm ^{-1 band} after Fenton treatment as well as the appearance of the band between 1150-1100 cm ^-1 are typical of the addition of C-OH bonds. The appearance of the band at 1700-1600 cm ^-1 and the amplification of the band 1320-1280 cm ^-1 confirm the presence of carbonyl groups on the surface of the ABS plates.

II.5. Reduction of ferric / ferrous ions

NaBH ₄ sodium borohydride (0.316 g, 0.8 × 10 ^-2 mol) is dissolved in 25 ml of a 0.1 M sodium hydroxide solution (NaOH). This solution is heated to 80 ° C. using a bain-marie and the samples are immersed in it. After 12 min, the samples were rinsed with MilliQ water before being dried.

IR analysis reveals the conservation of oxidation obtained after Fenton with bands at 3600-3200 cm ^-1 and bands 1700-1640 cm ^-1 .

II.6. Copper electroless metallization bath

The samples are immersed in a commercial Electroless plating bath (M Copper 85, MacDermid) with formaldehyde as reducing agent. At least the plates are immersed for 10 minutes at 48 ° C.

After 10 min, the samples were rinsed with MilliQ water, under ultrasound for 10 min before being dried.

Infrared analysis reveals the disappearance of the peaks of the different polymers.

The copper layer is visible to the eye.

II.7. Scotch test

To check the mechanical strength of the layers that have been grafted previously, a test with an adhesive tape was performed. It consists in sticking on the layer a piece of adhesive tape and then removing it from the layer.

If the deposited layer leaves with the adhesive, the mechanical strength is considered bad. If the layer remains insensitive to the adhesive, the mechanical strength is considered good.

The adhesive tape that was used is a high performance invisible adhesive tape, branded PROGRESS.

This test was carried out on an ABS plate after metallization with each time a pretreated part with the acid and an untreated part. The metallization is homogeneous. The results of this test show a better resistance on the pretreated part.

II.8. Electroplating copper deposit

In order to confirm the presence of a metal layer, copper was deposited by electroplating. This technique is only possible in the presence of conductive substrates.

Thus a copper-coated ABS plate has been used as an electrode measurement. The electrochemical system put in place consisted of a saturated KCl calomel reference electrode and a graphite counter electrode.

The electrodes were soaked in a solution of CuSO ₄ at 10 g / L, the initial potential was about 0 V.

A voltammetry cycle of up to -1 V in 30 was imposed on the system. During the voltage rise, the experiment was stopped at around -0.75 V ( Figure 4 ).

This cycle showed the deposition of copper on the measuring electrode. Indeed, the current increased when the voltage decreased and the copper was deposited on the plates acting as measuring electrode. Copper reduction took place at the measuring electrode.

The confirmation of the copper deposit is also visual. Indeed, the copper layer deposited by electrochemistry has a slightly more homogeneous appearance.

III. Metallization via pretreatment accompanied by Fenton treatment of ABS-PC plates .

This metallization process is carried out in 4 steps (Pretreatment Oxidizer / Fenton Treatment / Reduction / Electroless Metallization) and before treating the polymer, it is necessary to prepare it, degrease and clean.

III.1. Polishing

In a ^1st step, the plates are subjected to polishing to minimize edge effects and other defects introduced during the cutting of the plates.

III.2. Rinsing

In a 2 ^nd time, the plates were rinsed using an industrial soap solution TDF4 mixed with water (1 mL TDF4 4 mL of MilliQ H ₂ 0) under ultrasound for 10 min. The plates are then rinsed with MilliQ water, under ultrasound for 10 min.

III.3. Pretreatment acid

The plates are immersed for 10 min in a 30 wt% NaOH solution at a temperature of 90 ° C. The plates are then rinsed in 0.5M HCl solution under ultrasound for 10 min and then with MilliQ water under ultrasound for 10 min.

The results obtained for the contact angle measurements of a droplet of 2 μl of water deposited on the samples treated according to the treatment of Fenton ("After") or without treatment ("Virgin") are presented in Table 11. below. <b> Table 11 </ b>: <i> Measuring the contact angles of a drop </ i> ABS-PC Virgin 90 After acid pretreatment 67 °

The contact angle is lowered. The surface has become more hydrophilic due to its oxidation and the surface roughness has increased.

The analysis of the IR spectra is presented in Table 12 below. <i><b> Table 12 </ b>: IR Bands Appeared After Acid Pretreatment </ i> Polymer plates ABS-PC After basic treatment 3600-3200 cm ^-1 1660-1610 cm ^-1 1740-1700 cm ^-1 1320-1280 cm ^-1

The appearance of bands at 3600-3200 cm ^-1 and 1660-1610 cm ^-1 may be due to the presence of traces of water. On the other hand, the bands at 1740-1700 cm ^-1 and at 1320-1280 cm ^-1 are characteristic of carbonyl groups, carboxylic type COOH. This confirms surface oxidation. On the other hand, the disappearance of the ester band at 1772 cm ^-1 characteristic of polycarbonate is noted.

III.4. Pretreatment of Fenton

Iron (II) sulfate (6.961 g, 0.1 mol) was solubilized in 50 mL of 10 ^-3 M sulfuric acid in water. In this solution, the polymer plates were immersed. 10 mL (0.124 mol) of 35% hydrogen peroxide in water were then added, drip. After 25 min, the samples were rinsed with MilliQ water before being dried.

The results obtained for the contact angle measurements of a droplet of 2 μl of water deposited on the samples treated according to the Fenton treatment ("After Fenton") or before treatment ("after basic treatment)) are presented in Table 13 below. <i><b> Table 13 </ b>: Measuring the contact angles of a drop </ i> ABS-PC After basic treatment 67 ° After Fenton 0 to 5 °

The contact angle is clearly lowered. The surface has become very hydrophilic because of its oxidation.

The analysis of the IR spectra is presented in Table 14 below. <i><b> Table 14 </ b>: IR Bands Appearing After Fenton's Oxidative Treatment on Samples </ i> Polymer plates ABS-PC After Fenton 3600-3200 cm ^-1 1700-1600 cm ^-1 1320-1280 cm ^-1 1150-1100 cm ^-1

The amplification of the 3600-3200 cm ^{-1 band} after Fenton treatment as well as the appearance of the band between 1150-1100 cm ^-1 are typical of the addition of C-OH bonds. The appearance of bands at 1700-1600 cm ^-1 and the amplification of the band 1320-1280 cm ^-1 confirm the presence of carbonyl groups on the surface of ABS-PC plates.

III.5. Reduction of ferric / ferrous ions

NaBH ₄ sodium borohydride (0.316 g, 0.8 × 10 ^-2 mol) is dissolved in 25 ml of a 0.1 M sodium hydroxide solution (NaOH). This solution is heated to 80 ° C. using a bain-marie and the samples are immersed in it. After 12 min, the samples were rinsed with MilliQ water before being dried.

IR analysis reveals the conservation of oxidation obtained after Fenton with bands at 3600-3200 cm ^-1 and bands 1700-1640 cm ^-1 .

III.6. Copper electroless metallization bath

The samples are immersed in a commercial Electroless plating bath (M Copper 85, MacDermid) with formaldehyde as reducing agent. The exact composition of the copper bath is not known. At least the plates are immersed for 10 minutes at 48 ° C.

After 10 min, the samples were rinsed with MilliQ water, under ultrasound for 10 min before being dried.

Infrared analysis reveals the disappearance of the peaks of the different polymers.

The copper layer is visible to the eye.

III.7. Electroplating copper deposit

In order to confirm the presence of a metal layer, copper was deposited by electroplating. This technique is only possible in the presence of conductive substrates.

Thus a copper-metallized ABS-PC plate was used as the measuring electrode. The electrochemical system put in place consisted of a saturated KCl calomel reference electrode and a graphite counter electrode.

The electrodes were soaked in a solution of CuSO ₄ at 10 g / L, the initial potential was about 0 V.

A voltammetry cycle of up to -1 V in 30 sec has been imposed on the system. During the voltage rise, the experiment was stopped at around -0.75 V ( Figure 5 ).

This cycle showed the deposition of copper on the measuring electrode. Indeed, the current increased when the voltage decreased and the copper was deposited on the plates acting as measuring electrode. Copper reduction took place at the measuring electrode.

The confirmation of the copper deposit is also visual. Indeed, the copper layer deposited by electrochemistry has a slightly more homogeneous appearance.

REFERENCES

1. [1] Charbonnier, M., et al., "Plasma treatment process for palladium chemisorption onto polymers before electroless deposition", Journal of the Electrochemical Society 1996, 143, (2), 472-480 .
2. [2] Patent application CA 1 203 720 on behalf of OMI Int. Corp. published on April 29, 1986.
3. [3] Naudin, "Nomenclature, classification and chemical formulas of polymers"Engineer's Techniques 1995: A3035 .

Claims (9)

1. A method for coating a surface of a substrate in (co)polymer with a metal material comprising the successive steps of:

   a) subjecting said surface to an oxidizing treatment by a chemical reaction of the Fenton type in the presence of at least one precursor of said metal material;

   b) transforming said precursor into said metal material,

   characterized in that the oxidizing treatment of said step (a) consists in putting said surface of the substrate in contact with a solution containing at least one precursor of the metal material and a compound of formula ROOR in which R represents a hydrogen, an alkyl group comprising from 1 to 15 carbon atoms, an acyl group -COR' with R' representing an alkyl group comprising from 1 to 15 carbon atoms or an aroyl group -COAr with Ar representing an aromatic group comprising from 6 to 15 carbon atoms.
2. The method according to claim 1, characterized in that said substrate is selected from the group consisting of a nanoparticle, a microparticle, a button, a plug of cosmetic products, an electronic element, a door handle, a home electric appliance, glasses, a decorative object and a vehicle body element.
3. The method according to claim 1 or 2, characterized in that said (co)polymer is selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), acrylonitrile-butadiene-styrene/polycarbonate (ABS/PC), a polyamide (PA), a polyamine, a poly(acrylic acid), a polyaniline and a polyethylene terephthalate (PET).
4. The method according to any of claims 1 to 3, characterized in that said solution comprising at least one precursor of the metal material and a compound of formula ROOR is an acid solution.
5. The method according to any of the preceding claims, characterized in that said precursor of the metal material is selected from the group consisting of copper, silver, gold, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium and platinum ions.
6. The method according to any of the preceding claims, characterized in that said step (b) has successirre sub steps consisting in:

   b₁) optionally reducing said precursor of the metal material present at the surface of said substrate;

   b₂) putting into contact said precursor optionally reduced following step (b₁) in a solution containing at least one ion of the metal material.
7. The method according to claim 6, characterized in that the ion(s) of the metal material is(are) selected from the group consisting of Ag^-, Ag²⁺, Ag³⁺, Au⁺, Au³⁺, Co²⁺, Cu⁺, Cu²⁺, Fe²⁺, Ni²⁺, Pd⁺ and Pt⁺.
8. The method according to any of the preceding claims, characterized in that the surface of the substrate is subject, prior to said step (a) of the method, to a treatment capable of increasing its hydrophilicity and/or its roughness, said treatment being selected from the group consisting of sanding, abrasion, chemical treatment with a pickling bath, flame treatment, corona effect treatment and plasma treatment and combinations thereof.
9. The method according to claim 8, characterized in that said pickling bath is an acid aqueous solution comprising at least one inorganic acid notably selected from the group consisting of chromic acid, sulfuric acid, nitric acid, hypochlorous acid and mixtures thereof.

Images