EP3256620B1 - Method for producing metal patterns on a substrate for decorative and/or functional purposes, manufacture of objects incorporating said method and set of consumables used - Google Patents

Description

Technical area

The technical field of the invention is that of the surface coating of substrates, with single or multi-layered metal films.

The present invention relates to processes for the metallization of substrates for decoration, for example applicable to hollow glasses, to bottles, to cosmetic parts, to parts for aeronautics, for the automobile industry and for home automation. The present invention also relates to metallization for functional purposes, for example for the manufacture of substrates for electronics, in particular printed circuits, integrated circuits on a semiconductor substrate, radio-identification chips (RFID), pictograms. coding readable by electronic readers .... This metallization, in certain cases, can be likened to printing.

In general, the substrates more specifically concerned with metallization are materials of all kinds, in particular non-conductors such as glass, plastics (polyolefins-polypropylene-, polycarbonates, polyesters, styrenics - Acrylonitrile-Butadiene-Styrene -), ceramics, wood, textiles, minerals, articles in plaster or cement; semiconductors, conductors.

Technological background

There are conventionally two main types of surface metallization processes for substrates: electrolytic metallization processes and non-electrolytic metallization processes.

Electrolytic metallization processes, also called electroplating, are based on an oxidation-reduction reaction using an electric current. The metal is supplied in cationic form in an aqueous medium. An electric current is imposed between the substrate that is to be metallized and a counter electrode. The metal cation is then reduced to the surface of the substrate. One of the major drawbacks of electrolytic deposition is that the substrate that is to be metallized must necessarily be conductive. This type of metallization is therefore not possible for substrates made of polymer, glass, etc.

The non-electrolytic metallization processes do not use an electric current. The metal is deposited by other means, dry or wet. Among the so-called dry method methods include PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition), which have the major drawback of the need to put the substrate under vacuum in order to carry out the metallization.

The so-called wet methods, which are technologically simpler to implement, are more common, and among them, mention may in particular be made of the non-electrolytic metallization by immersion called the "electroless method".

In a non-electrolytic immersion metallization process, the metal is also supplied in cationic form in an aqueous medium. A reducing agent is also present in the medium, as well as generally a complexing agent. The bath is prepared in such a way that although the metal salt and the reducing agent are present together in the bath, the direct oxidation-reduction reaction is prevented. This is only possible in the presence of a catalyst. This is why the surface of the substrate which is to be metallized is treated beforehand with sensitizing and possibly activating agents which will make the surface catalytic. In the presence of the catalytic surface, the metal salts are reduced by direct reaction with the reducing agent present in the medium.

This non-electrolytic immersion metallization technique is conventionally used in the surface treatment industry.

• Les bains de dépôt peuvent être instables, et le sel métallique peut précipiter avant l'introduction du substrat.
• La cinétique du dépôt est lente.
• l'utilisation des catalyseurs chimiques est coûteuse.
• les gammes de traitements comprennent de nombreuses étapes.
• la maintenance régulière des bains est nécessaire.
• Il est difficile de procéder à des dépôts simultanés de plusieurs métaux.
• L'adhérence du dépôt métallique au substrat est faible, ce qui rend le dépôt très fragile.

Here too, many disadvantages are to be noted, and in particular:

• The deposition baths can be unstable, and the metal salt can precipitate before the introduction of the substrate.
• The kinetics of the deposit are slow.
• the use of chemical catalysts is expensive.
• the treatment lines include many stages.
• regular maintenance of the baths is necessary.
• It is difficult to make simultaneous deposits of several metals.
• The adhesion of the metal deposit to the substrate is low, which makes the deposit very fragile.

These non-electrolytic wet metallization processes have been the subject of a recent technological advance, based on the principle of spraying aerosols. This is the “JetMetal®” process, perfected and developed by the applicant, and in which one or more aqueous redox solutions are sprayed onto the substrate to be metallized in the form of aerosols. The metal, present in the form of a metal salt in solution, is then brought into contact with a reducing agent, and it is immediately deposited directly on the substrate. The metal film obtained at the end of a metallization according to the “JetMetal®” process is therefore formed by the deposited metal atoms. This deposit can conventionally be rinsed and then dried. No heat treatment is necessary to obtain a homogeneous and continuous metallic deposit on the substrate.

This “JetMetal®” aerosol metallization process is described in particular in the documents FR2763962B1 , EP2326747B1 , EP2318564B1 . It has notable advantages over other existing non-electrolytic metallization processes. JetMetal® makes it possible in particular to obtain, on an industrial scale, with little or no pollution, at room temperature and at atmospheric pressure, substrates metallized with a homogeneous and continuous metal film.

Several techniques are known, moreover, for affixing metal patterns to substrates for either decorative or functional purposes (printed circuits, RFID antennas, etc.).

• → soit additives (dépôt de métal) : l'impression d'encre à base d'argent; le masquage temporaire;
• → soit soustractives (gravure du métal déjà présent): la photogravure (photolithographie), la gravure laser.

These techniques are:

• → either additives (metal deposit): printing ink based on silver; temporary masking;
• → or subtractive (engraving of the metal already present): photoengraving (photolithography), laser engraving.

Additive techniques:

In silver-based ink printing, conductive patterns are produced by direct printing (screen printing or inkjet printing), using inks loaded with silver particles. A heat treatment is necessary in order to remove the solvent contained in the inks and to obtain a conductive pattern. The electrical conductivity of the patterns thus formed is less than that of a continuous metal film obtained by other metal deposition techniques.

Temporary masking consists of applying a mask (adhesives, peelable varnishes, stencils, etc.) to a surface to be protected in order to prevent the metallization of certain areas; this technique is difficult to apply to obtain complex patterns and requires a mechanical action which is not very compatible with mass production.

Subtractive techniques:

Photoengraving is widely used in the electronics industry for the production of printed circuits. The base substrate consists of an assembly comprising a layer of copper on an epoxy / glass fiber support. The copper is covered with a photosensitive resin ("photoresist") which is exposed through a typon (printed mask presenting the patterns): this is the exposure stage. The insolated resin is polymerized under the effect of light. A suitable development solution is then used to solubilize the uncured resin. A chemical etching solution is then applied to attack the copper not protected by the polymerized resin (etching or "etching" step). Finally, the substrate is brought into contact with an extraction solution, in order to remove any trace of polymerized resin (“stripping” or “stripping” step). (see Fig. 1 annexed).

Laser engraving involves using a laser to selectively extract the metal already present on a substrate. Although very precise, this method can be expensive and difficult to implement for extensive reasons.

It therefore appears that there is a lack in the existing industrial technique of surface treatment making it possible to deposit in a durable way metallic patterns likely to be fine, precise and complex (arabesques-interlacing-calligraphy ...), as well in the plane of the surface of the substrate coated with said patterns, than in the thickness of said patterns.

Technical problem - Objectives of the invention

One of the technical problems at the basis of the present invention is to remedy this deficiency of the prior art.

• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui soit aisément industrialisable et automatisable ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui soit simple à mettre en œuvre ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui soit économique ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui soit applicable en ligne sans temps d'arrêt entre chaque étape et intégrable sur des lignes de laquage traditionnelle ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui conduise à des motifs métalliques adhérant parfaitement et de manière durable sur le substrat ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui conduise à des motifs métalliques homogènes et réguliers quant à leur surface et leur épaisseur ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui conduise à des motifs métalliques qui soient suffisamment épais notamment pour des applications de conduction électrique;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui conduise à des motifs métalliques durs et résistants aux agressions de toutes sortes ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, dont les consommables sont à base de matériaux courants, simples et peu onéreux et dont la formulation est facile à mettre en œuvre ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui soit "propre" ou éco-compatible, c'est-à-dire utiliser des solutions peu ou non toxiques ou en très faibles quantités et permettre le recyclage des effluents issus du procédé ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui permet de réaliser des motifs métalliques de décoration (effet miroir des motifs) sur des pièces planes ou en 3D ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui apporte de la flexibilité aux installations industrielles le mettant en œuvre : installations simplifiées, étapes de fabrication supprimées, gain de productivité, etc ;
• → fournir un procédé de réalisation de motifs métalliques susceptibles d'être fins, précis et complexes sur tout type de substrats, qui permette d'obtenir des motifs métalliques variés (argent, cuivre, nickel...) en ligne dans des installations traditionnelles industrielles de laquage et/ou de métallisation liquide ;
• → fournir un dispositif industriel, économique et performant pour la mise en œuvre du procédé tel que visé dans au moins l'un des objectifs ci-dessus ;
• → fournir un ensemble de consommable(s) économique(s) et performant(s) susceptibles d'être utilisé dans le procédé tel que visé dans au moins l'un des objectifs ci-dessus.

The present invention therefore aims to satisfy at least one of the following objectives:
The improvements sought are in particular in at least one of the following areas:

• → provide a process for producing metal patterns that can be fine, precise and complex on all types of substrates, which can be easily industrialized and automated;
• → provide a process for producing metallic patterns that may be thin, precise and complex on all types of substrates, which is easy to implement;
• → provide a process for producing metallic patterns that may be thin, precise and complex on all types of substrates, which is economical;
• → provide a process for producing metallic patterns that can be fine, precise and complex on all types of substrates, which can be applied online without downtime between each step and can be integrated on traditional lacquering lines;
• → provide a process for producing metallic patterns that can be fine, precise and complex on any type of substrate, which leads to metallic patterns that adhere perfectly and durably to the substrate;
• → provide a process for producing metal patterns that can be thin, precise and complex on any type of substrate, which leads to metallic patterns that are homogeneous and regular in terms of their surface and their thickness;
• → provide a process for producing metallic patterns that can be thin, precise and complex on any type of substrate, which leads to metallic patterns that are sufficiently thick, in particular for electrical conduction applications;
• → provide a process for producing metallic patterns that can be fine, precise and complex on any type of substrate, which leads to hard metallic patterns that are resistant to attacks of all kinds;
• → provide a process for producing metal patterns that may be fine, precise and complex on all types of substrates, the consumables of which are based on common materials, simple and inexpensive and whose formulation is easy to use;
• → provide a process for producing metallic patterns that may be fine, precise and complex on any type of substrate, which is "clean" or eco-compatible, that is to say using solutions with little or no toxic or very low quantities and allow the recycling of effluents from the process;
• → provide a process for producing metallic patterns that may be thin, precise and complex on all types of substrates, which makes it possible to produce decorative metallic patterns (mirror effect of patterns) on flat or 3D parts;
• → provide a process for producing metal patterns that may be thin, precise and complex on all types of substrates, which provides flexibility to industrial installations using it: simplified installations, eliminated manufacturing steps, increased productivity, etc. ;
• → provide a process for producing metallic patterns that can be fine, precise and complex on all types of substrates, which makes it possible to obtain various metallic patterns (silver, copper, nickel, etc.) online in traditional industrial installations liquid lacquering and / or metallization;
• → provide an industrial, economical and efficient device for the implementation of the process as referred to in at least one of the above objectives;
• → provide a set of economical and efficient consumable (s) likely to be used in the process as referred to in at least one of the above objectives.

Brief description of the invention

• en ce qu'il comprend les étapes essentielles suivantes :
  1. A. éventuellement une préparation de la surface du substrat destinée à recevoir les motifs métalliques ;
  2. B. dépôt d'une protection temporaire sur la surface du substrat correspondant au négatif des motifs à réaliser au moyen d'un masque de sérigraphie/pochoir dont les évidements correspondent au négatif des motifs à réaliser ; et/ou par impression directe, de préférence par jet d'encre ;
  3. C. éventuellement une activation de la surface du substrat, en particulier des zones correspondant aux motifs à réaliser ;
  4. D. métallisation du substrat par un dépôt d'au moins un métal, en particulier des zones correspondant aux motifs à réaliser ;
  5. E. élimination de la protection temporaire de l'étape B;
  6. F. éventuellement rinçage de la surface du substrat portant les motifs métalliques ;
  7. G. éventuellement séchage de la surface du substrat portant les motifs métalliques ;
  8. H. éventuellement traitement de finition sur la surface du substrat portant les motifs métalliques ;
• et en ce que l'étape E d'élimination de la protection temporaire est effectuée, pendant l'étape D, ou au moins en partie pendant l'étape D et après l'étape D, ou au moins en partie pendant et après l'étape de métallisation D et en partie avant l'étape de métallisation D,

en ce que l'étape E consiste essentiellement en une dissolution de la protection temporaire par au moins un solvant contenu dans au moins une des solutions de métallisation, ledit solvant étant de préférence alcalin et ladite protection temporaire étant de préférence alcali-soluble de manière à pouvoir être dissoute de préférence par ledit solvant,
et en ce que le dépôt métallique D est une métallisation non électrolytique par projection d'une ou plusieurs solutions oxydo-réductrices sous forme d'aérosol(s).All or part of the aforementioned objectives is achieved by the present invention which relates, according to the first of its aspects, to a method for producing metallic patterns on a substrate characterized

• in that it includes the following essential steps:
  1. A. optionally, a preparation of the surface of the substrate intended to receive the metallic patterns;
  2. B. deposition of a temporary protection on the surface of the substrate corresponding to the negative of the patterns to be produced by means of a screen printing mask / stencil, the recesses of which correspond to the negative of the patterns to be produced; and / or by direct printing, preferably by inkjet;
  3. C. optionally an activation of the surface of the substrate, in particular of the zones corresponding to the patterns to be produced;
  4. D. metallization of the substrate by depositing at least one metal, in particular areas corresponding to the patterns to be produced;
  5. E. elimination of the temporary protection of step B;
  6. F. optionally rinsing the surface of the substrate bearing the metallic patterns;
  7. G. optionally drying the surface of the substrate bearing the metallic patterns;
  8. H. optionally finishing treatment on the surface of the substrate bearing the metallic patterns;
• and in that step E of removing the temporary protection is carried out, during step D, or at least partly during step D and after step D, or at least partly during and after l 'metallization step D and partly before the metallization step D,

in that step E consists essentially of dissolving the temporary protection with at least one solvent contained in at least one of the metallization solutions, said solvent preferably being alkaline and said temporary protection preferably being alkali-soluble so as to be able to be dissolved preferably by said solvent,
and in that the metallic deposit D is a non-electrolytic metallization by projection of one or more redox solutions in the form of aerosol (s).

It is to the credit of the inventors to have developed this selective metallization technique which can be put online which is based in particular on the use of temporary protection on certain areas of the surface of the substrate which form the negative of the metallization patterns. revised. This temporary protection has the particularity of being able to be easily and cleanly removed from the surface of the substrate intended to receive the metallic patterns, so that the fineness and precision of the metallic patterns, even complex, are not damaged during this removal operation. . The inventors propose a removal of the temporary protection by dissolution in a solvent contained in at least one of the metallization solutions during step D, or at least partially during and after this metallization D, or at least partially during and after the metallization step D and partly before the metallization step D.
In practice, the elimination E of the temporary protection can be completely achieved during the metallization. In this hypothesis, the duration of this elimination E is less than or equal to the duration of the metallization D.
According to one alternative, this elimination E takes place partly during metallization D and in part after this metallization D.
According to another alternative, this elimination E takes place partly during and after the metallization step D and in part before the metallization step D.

1. i) il donne accès à des motifs métalliques décoratifs et/ou fonctionnel de formes complexes, notamment à des éléments scripturaux très fin ;
2. ii) il est compatible avec les exigences industrielles de productivité et de qualité notamment en termes de dureté et d'adhérence au substrat ;
3. iii) il est simple à mettre en œuvre et il est économique ;
4. iv) il est applicable à une multiplicité de substrats conducteurs ou non-conducteurs ;
5. v) le spectre des métaux ou alliages déposables est très large ;
6. vi) les consommables, en particulier les solutions, utilisés sont stables ;
7. vii) la finesse des motifs et l'épaisseur du dépôt est facilement contrôlable ;
8. viii) il est possible de réaliser des alliages ou des motifs métalliques composites.

This process has the following advantages in particular:

1. i) it gives access to decorative and / or functional metallic patterns of complex shapes, in particular to very fine scriptural elements;
2. ii) it is compatible with industrial productivity and quality requirements, in particular in terms of hardness and adhesion to the substrate;
3. (iii) it is simple to implement and it is economical;
4. iv) it is applicable to a multiplicity of conductive or non-conductive substrates;
5. v) the spectrum of metals or alloys which can be deposited is very wide;
6. vi) the consumables, in particular the solutions, used are stable;
7. vii) the fineness of the patterns and the thickness of the deposit are easily controllable;
8. viii) it is possible to produce alloys or composite metal patterns.

• un entraînement en phase liquide ;
• un entraînement mécanique par un gaz de préférence l'air.

According to a remarkable characteristic of the invention, step E further comprises at least one of the following operations:

• liquid phase entrainment;
• mechanical drive by a gas, preferably air.

• I. traitement d'augmentation de l'énergie de surface du substrat; sachant que dans le cas où le procédé comprend une étape d'activation C., une étape I. d'augmentation de l'énergie de surface du substrat peut être éventuellement prévue avant l'activation C.
• J. mouillage de la surface du substrat ;
• K. rinçage de la surface du substrat.

According to a first mode of implementation according to the invention, the metallic deposit D is a non-electrolytic metallization by spraying one or more redox solutions in the form of aerosol (s).
In addition, this first mode of implementation optionally comprises, before metallization D, at least one of the following steps, preferably in the following order:

• I. treatment to increase the surface energy of the substrate; knowing that in the case where the method comprises an activation step C., a step I. of increasing the surface energy of the substrate can optionally be provided before the activation C.
• J. wetting the surface of the substrate;
• K. rinsing the substrate surface.

Preferably, the metal of step D is chosen from the following group of metals: silver, nickel, copper, tin, iron, gold, cobalt, their oxides, their alloys and their combinations.

In the case where the method comprises a step A of preparing the surface of the substrate intended to receive the metallic patterns, said step A comprises the deposition of at least one layer of varnish and / or the degreasing of said surface. Advantageously, the deposited varnish may consist of at least one organic layer containing or not containing (pigments / dyes) crosslinked in temperature (for example a polyurethane, such as that in the form of water-soluble powder) and / or under exposure by a actinic radiation, for example UV.

• L. satinage, de préférence mis en œuvre entre l'étape B et l'étape C ;
• M. rinçage de la surface du substrat en cas de satinage selon l'étape L.

Selon un troisième mode de mise en œuvre non conforme à l'invention, le substrat est un matériau conducteur en tant que tel ou traité pour le devenir (c'est à dire rendu préalablement conducteur par les techniques de l'art) et le dépôt métallique D est une métallisation électrolytique.The optional treatment for increasing the surface energy of the substrate according to step I, which can be likened to a step A. of preparing the surface of the substrate, is chosen from the physical treatments, preferably the following physical treatments : flaming, a plasma treatment and their combinations, and / or among the chemical treatments, preferably the following chemical treatments: application of a silane-based solution, depassivation of the surface using one or more acid solutions, a rare earth oxide polishing, fluorination and combinations thereof. According to a second embodiment not in accordance with the invention, the metal deposit D is an auto-catalytic chemical metallization (of the electroless type) or metallization by displacement, by immersion in one (or more) solution (s) of metallization suitable (s) and in that it comprises activation C and optionally, before activation C, at least one of the following steps, preferably in the following order:

• L. satin finishing, preferably carried out between step B and step C;
• M. rinsing the surface of the substrate in case of satin finishing according to step L.

According to a third embodiment not in accordance with the invention, the substrate is a conductive material as such or treated to become so (that is to say made previously conductive by the techniques of the art) and the deposit metallic D is an electrolytic metallization.

According to an advantageous embodiment of the invention, the metallization process to which it relates can include the first mode and possibly the second mode and / or the third mode of implementation referred to above.

According to a preferred characteristic of the invention, the solvent allowing the dissolution of the temporary protection is contained in at least one of the liquids used for the metallization step D and also in the liquids used in at least one rinsing step and the duration of this metallization step D is preferably less than or equal to the duration of dissolution of the temporary protection.

Advantageously, the metallic patterns obtained are decorative and / or functional and are, preferably, included in the group comprising -preferably constituted by: printed circuits, integrated circuits on a semiconductor substrate, radio-identification chips (RFID ) coding pictograms likely to be read by electronic devices, figurative and / or scriptural information identifying a product, in particular a commercial product, such as a visual or a decorative design on a cosmetic and / or automobile product.

According to a remarkable characteristic of the invention, the method according to the invention is implemented continuously / in line on industrial equipment, for example lacquering and / or liquid metallization.

According to a second of its aspects, the present invention relates to a method of manufacturing objects comprising metallic patterns, preferably decorative and / or functional, characterized in that it implements the method according to at least one of the preceding claims.

1. i. un module de dépôt d'une protection temporaire sur la surface du substrat ;
2. ii. un module de métallisation ;
3. iii. éventuellement un module de réalisation d'une couche de finition, et/ou ;
4. iv. éventuellement un module de préparation de la surface du substrat destinée à recevoir les motifs métalliques ; et/ou ;
5. v. éventuellement au moins un masque de sérigraphie/pochoir utile dans l'une des variantes de l'étape B ; et/ou ;
6. vi. éventuellement un module d'activation de la surface du substrat de l'étape C ; et/ou ;
7. vii. éventuellement un module d'élimination selon l'étape E de la protection temporaire de l'étape B ; et/ou ;
8. viii. éventuellement un module de rinçage selon l'étape F ; et/ou ;
9. ix. éventuellement un module de dépôt d'au moins une couche de finition selon l'étape H.

According to a third of its aspects, the present description relates to a device for implementing the method according to the invention, characterized in that it comprises:

1. i. a module for depositing a temporary protection on the surface of the substrate;
2. ii. a metallization module;
3. iii. optionally a module for producing a finishing layer, and / or;
4. iv. optionally, a module for preparing the surface of the substrate intended to receive the metallic patterns; and or ;
5. v. optionally at least one screen printing / stencil mask useful in one of the variants of step B; and or ;
6. vi. optionally a module for activating the surface of the substrate of step C; and or ;
7. vii. optionally, an elimination module according to step E of the temporary protection of step B; and or ;
8. viii. optionally a rinsing module according to step F; and or ;
9. ix. optionally, a deposition module of at least one topcoat according to step H.

According to an advantageous embodiment, this device can be on-line on industrial installations, for example on a liquid coating and / or metallization line.

1. a. consommable(s) pour la réalisation de la protection temporaire de l'étape B, ladite protection temporaire étant soluble dans un solvant alcalin ;
2. b. consommable(s) pour la métallisation de l'étape D, comprenant une ou plusieurs solutions oxydo-réductrices contenant un ou plusieurs cations métalliques oxydants et/ou un ou plusieurs composés réducteurs, au moins l'une desdites solutions contenant un solvant alcalin ;
3. c. éventuellement, consommable(s) pour la préparation de la surface du substrat destinée à recevoir les motifs métalliques de l'étape A ; et/ou ;
4. d. éventuellement au moins un masque de sérigraphie/pochoir utile dans l'une des variantes de l'étape B ; et/ou ;
5. e. éventuellement consommable(s) pour l'activation de la surface du substrat de l'étape C ; et/ou ;
6. f. éventuellement consommable(s) pour l'élimination selon l'étape E de la protection temporaire de l'étape B ; et/ou ;
7. g. éventuellement consommable(s) pour le rinçage selon l'étape F ; et/ou ;
8. h. éventuellement consommable(s) pour le dépôt d'au moins une couche de finition selon l'étape H ;

According to a fourth of its aspects, the present invention relates to a set of consumables for the implementation of the method according to the invention, characterized in that it comprises:

1. at. consumable (s) for achieving the temporary protection of step B, said temporary protection being soluble in an alkaline solvent;
2. b. consumable (s) for the metallization of step D, comprising one or more redox solutions containing one or more oxidizing metal cations and / or one or more reducing compounds, at least one of said solutions containing an alkaline solvent;
3. vs. optionally, consumable (s) for the preparation of the surface of the substrate intended to receive the metallic patterns of step A; and or ;
4. d. optionally at least one screen printing / stencil mask useful in one of the variants of step B; and or ;
5. e. optionally consumable (s) for activating the surface of the substrate in step C; and or ;
6. f. optionally consumable (s) for the elimination according to step E of the temporary protection of step B; and or ;
7. g. optionally consumable (s) for rinsing according to step F; and or ;
8. h. optionally consumable (s) for depositing at least one topcoat according to step H;

Definitions

Throughout this presentation, any singular designates indifferently a singular or a plural.

The definitions given below by way of example can be used for the interpretation of this presentation.

The term “ aerosol ” is understood to mean that it is eg a mist of droplets of size less than 100 μm, preferably less than 60 μm, and more preferably still from 0.1 to 50 μm, which is carried out by nebulization and / or atomization of solution (s) and / or dispersion (s).

The terms “non-electrolytic metallization” relate in particular to the process described in FR2763962B1 , EP2326747B1 , or EP2318564B1 .

Detailed description of the invention Substrates:

The substrate may be a non-conductive material, a semiconductor material or a conductive material.

In the case where it is a non-conductive material, it can be chosen from the group comprising - or ideally constituted by: glass, plastics / (co) polymer (polyolefins-polypropylene-, polycarbonates, polyesters, styrenics -Acrylonitrile-Butadiene-Styrene-), composite materials, ceramics, textiles, wood, minerals, articles made of plaster or cement.

If a conductive material is contemplated as the substrate, this could be a metal.

The semiconductor material capable of being a substrate is one of those commonly used in the semiconductor industry.

Under certain conditions for implementing the method described here, the substrate is a rigid, conductive or non-conductive substrate as defined above. Particularly preferred are rigid hollow glass substrates and rigid polymeric substrates.

Within the meaning of the invention, a hollow glass substrate is a non-planar glass substrate, in particular a glass container such as a flask or a glass bottle.

Under other preferential conditions for implementing the method of the invention, the substrate is a flexible substrate. It is, for example, chosen from the following compounds: polymers, metals, textiles, metal strips and paper. Preferably, the flexible substrate is a textile or a polymer film. For example, the flexible substrate is a polyester film whose thickness is 100 μm to 5 mm, a fabric or a sheet of paper whose density is 50 to 600 g / m2.

In the present disclosure, the term “flexible substrate” is understood to mean a substrate which can be bent, bent by human force alone without breaking or being damaged.

By contrast, in the present description, the term “rigid substrate” is understood to mean a substrate which cannot be bent or bent by human force alone without breaking or being damaged.

Step A: Preparation of the surface of the substrate intended to receive the metallic patterns

This surface preparation step can take place before or after the application of the temporary protection.

In certain cases, the preparation of the substrate before application of the temporary protection makes it possible not to subject this layer to physico-chemical modifications, which could lead to its attachment to the substrate and a more difficult elimination (preferably solubilization) of the protection. temporary.

In other cases, the surface preparation can intervene voluntarily after application of the temporary protection, in order to reinforce its cohesion and to slow down its elimination (preferably solubilization).

Such a preparation can comprise a cleaning / degreasing of the surface, by means of any products known per se and suitable.

In addition to or instead of this cleaning / degreasing, it is possible to deposit on the surface of the substrate a varnish, for example a UV crosslinking varnish applied by spraying, by any known and appropriate means such as a paint gun. compressed air (eg HVLP: high volume low pressure).

According to one variant, step A can include at least one treatment for increasing the energy of the surface (step I.).

Step B.: Deposit of a temporary protection on the surface of the substrate corresponding to the negative of the patterns to be produced Temporary protection

In accordance with a remarkable arrangement of the invention, this temporary protection is a coating corresponding to the negative of the desired patterns. This coating is obtained from a liquid product which dries and / or which hardens once applied to the surface of the substrate and / or which crosslinks under actinic radiation, for example UV.

This liquid product has the singularity of being soluble in at least one of the solvents subsequently employed in the process according to the invention. It may in particular be a product soluble in an alkaline solvent.

This temporary protection product can comprise, for example, an ink and or any other organic product having a high solubility in an appropriate solvent.

According to one variant, the liquid product used for producing the protective coating can be a product which, after drying and / or curing and / or crosslinking under actinic radiation, for example UV, gives rise to a coating whose adhesion to the substrate. can be reduced by at least one of the substances - preferably liquid -, in particular solvents, subsequently employed in the process according to the invention. By way of example of such a protective product, mention may be made of alkali-sensitive inks.

• B.1 : Le dépôt de la protection temporaire peut être effectué par l'intermédiaire de toute technique connue d'application, par exemple au moyen d'un masque de sérigraphie/pochoir, offset, flexographie, tampographie, ou tout autre technologie de transfert.
  Le masque de sérigraphie/pochoir est par exemple fabriqué dans une matière constituée par un matériau polymère et de la manière traditionnelle connue de l'homme du métier.
• B.2 : Dans un autre cas, le dépôt de la protection temporaire peut être effectué par une technique permettant une impression fine, précise et nette sur un substrat. L'impression par jet d'encre ou la dépose par un stylo contenant l'encre appropriée, sont des exemples répondant à ce cahier des charges.

Of course, it is not necessary, as in the case of traditional printing, that the ink be pigmented. However, an ink containing a dye will allow visualization of the temporary protection applied to the surface of the substrate, which can be practical.

• B.1 : The temporary protection can be deposited by means of any known application technique, for example by means of a screen printing / stencil mask, offset, flexography, pad printing, or any other transfer technology .
  The screen printing mask / stencil is for example made from a material consisting of a polymer material and in the traditional manner known to those skilled in the art.
• B.2 : In another case, the deposition of the temporary protection can be carried out by a technique allowing a fine, precise and clear impression on a substrate. Inkjet printing or depositing with a pen containing the appropriate ink are examples that meet this specification.

Step C.: Activation of the surface of the substrate, in particular of the areas corresponding to the patterns to be produced

C.1 : When step D is non-electrolytic metallization by spraying one or more redox solutions in aerosol form, activation C is necessary for certain metals. It aims to accelerate the oxidation-reduction reaction involved in this step D.

During this step C, at least one sensitizing chemical species is adsorbed on the surface of the material and thus accelerates the metallization reaction.

If temporary protection is present, and it is preferably present, the sensitizing chemical species (s) adsorb onto the unprotected substrate and onto the protective layer.

To carry out this step C, a sensitizing solution will preferably be applied by spraying on the surface of the substrate, preferably coated with the temporary protection. This spraying is carried out by any known and appropriate means such as a compressed air paint gun (eg HVLP: high volume low pressure). According to one variant, it may be an immersion.

For example, a first sensitizing solution based on stannous chloride (SnCl ₂ ) or SnSO ₄ / H ₂ SO ₄ / quinol / alcohol, is applied by spraying or immersion. A palladium or silver solution capable of reacting with Sn ²⁺ to form nucleation centers on the surface of the substrate, or else a PdSn colloidal solution formed ex situ, is then deposited in the same way. For more precision, one could refer for example to " Metal Finishing Guidebook and Directory Issue ", 1996 Metal Finishing publication, pages 354, 356 and 357 . H. Narcus "Metallizing of Plastics", Reinhold Publishing Corporation, 1960, Chapter 2, page 21 . F. Lowenheim, "Modern electroplating", John Wiley & Sons publication, 1974 Chapter 28, page 636 .

Advantageously, the step of sensitizing the surface of the substrate is carried out by means of a sensitizing solution based on stannous chloride, for example in accordance with the mode of implementation described in FR-A-2 763 962 . In this case, a rinsing step using a rinsing liquid as described below is carried out just after the sensitization step, without an intermediate step.

According to a variant, the activation of the surface of the substrate is carried out by means of a sensitizing solution, in particular of palladium chloride, for example in accordance with the mode of implementation described in FR2763962B1 . In this case, a rinsing step using a rinsing liquid as described in the examples below is carried out just after the activation step, without an intermediate step.

C.2 : When step D is a chemical metallization (called "electroless") without electric current / auto-catalytic, by immersion in one (or more) suitable metallization solution (s), activation C which aims to accelerate the catalytic oxidation-reduction reaction occurring in this step D, is generally essential. It consists in depositing on the surface of the substrate, coated with the temporary protection, a chemical metallization catalyst without current, for example a catalyst of the Sn / Pd type. The catalyst is adsorbed over the entire surface of the substrate (unprotected areas corresponding to the patterns to be affixed and temporary protective layer).

This activation C is preferably preceded by a step L (satin finish) followed by a step M (rinsing).

Step L:

This satin-finishing step is in fact a treatment for increasing the surface energy of the substrate and / or for increasing the roughness of the substrate, which may be of the type defined below for step I.

In the case of currentless metallization, the satin finish is preferably carried out by physical treatment (corona discharge, plasma treatment) or chemical (eg sulfo-chromic treatment or other) in order to give sufficient adhesion to the metallic patterns to be deposited. .

Step M:

This is a rinse of the type defined below for step K.

Step D.: Metallization D.1 : Metallization by aerosol projection

The following steps: step I. (treatment to increase the surface energy of the substrate), step J (wetting the surface of the substrate) and step K (rinsing the surface of the substrate), which can precede step C or step D., are described below, prior to the description of D1.

Stage I .:

The treatment for increasing the surface energy of the substrate according to step I is chosen from physical treatments, preferably the following physical treatments: flame treatment, plasma treatment and their combinations, and / or chemical treatments, preferably the following chemical treatments: application of a solution based on silane, depassivation of the surface using one or more acid solutions, polishing based on rare earth oxide, fluorination and combinations thereof .

Preferably, the physical treatment of step I is a flame treatment.
In addition, the physical treatment is advantageously a treatment by flame treatment and / or by plasma, when the substrate is a rigid substrate made of plastic, of composite material, of polymer or of a flexible support of polymer, metal such as a metal strip. , textile or paper. Flaming is, for example, the passage of the substrate to be metallized under a flame, the temperature of which is eg from 1200 ° C to 1700 ° C. The duration of flaming is generally 4 to 50 seconds. The flame is preferably obtained by combustion of a fuel such as propane gas (or town gas) in the presence of an oxidizer such as oxygen.

The (by) plasma treatment corresponds, for example, to the passage of the substrate to be metallized in a plasma torch, for example those marketed by ACXYS® or PLASMATREAT®.

In step I, the chemical treatment is preferably chosen from the following treatments: application of a solution based on silane, passivation of the surface using one or more acid solutions, polishing based on silane rare earth oxide, fluorination and combinations thereof.
Even more preferably, the chemical treatment is an application of a silane-based solution, a passivation by spraying of one or more acid solutions, a fluorination or their combinations.
In addition, this chemical treatment is more especially implemented when the substrate is a rigid substrate made of hollow glass, metal or alloy.
Passivation means, for example, that the surface of the substrate is corroded until the oxide layer covering it is removed, by the action of a corrosive substance projected onto the surface. substrate, such as a strong acid solution, for example based on nitric, citric or sulfuric acid and their mixtures.
The "rare earth oxide-based polishing" means, for example, that a rare earth oxide-based solution is applied to the substrate to be metallized and that pads come to polish the surface of the substrate, in particular by friction against the substrate. its surface, until a possible oxide layer present on the surface is removed and smoothed. Preferably, the solution based on rare earth oxide is a solution based on cerium oxide, which is for example of the type marketed by the company POLIR-MALIN® under the name GLASS POLISHING®. Preferably, the polishing based on rare earth oxide comprises a step of rinsing the surface thus polished, in particular with distilled water.
Fluorination corresponds, for example, to bringing the substrate to be metallized and a gaseous solution based on inert gas (argon) containing a fluorine additive into contact, in an enclosure under reduced pressure. According to the invention, the fluorination is carried out for example with an apparatus of the type of those marketed by AIR LIQUIDE®.

These physical or chemical treatments to increase the surface energy of the substrate must be carried out so that the surface energy of the substrate is greater than or equal to 50 or 55 dynes, preferably greater than or equal to 60 or 65 dynes , and even more preferably greater than or equal to 70 dynes. Below these values, the wetting of the substrate is insufficient and the metallic coating obtained after metallization has unsatisfactory characteristics of adhesion, gloss and reflectivity. The value of the surface energy can be measured, for example, by techniques known to those skilled in the art consisting in applying to the substrate, using a brush or a felt-tip pen, a specific solution and to measure the retraction time of the solution thus applied.

Step J:

The wetting step J consists in coating the surface of the substrate with a liquid film to promote the spreading of the redox solutions. The choice of the wetting liquid is made from the following group: deionized water or not, optionally added with one or more anionic, cationic or neutral surfactants, an alcoholic solution comprising one or more alcohols (for example isopropanol, l ethanol and their mixture), and their mixtures. In particular, deionized water added with an anionic surfactant and ethanol is chosen as the wetting liquid. In a wetting variant according to which the wetting liquid is converted into vapor which is sprayed onto the substrate on which they condense, it is preferable that the liquid be essentially aqueous for obvious reasons of industrial convenience. The wetting time depends on the surface of the substrate considered and the rate of projection of the wetting aerosol.
The wetting step can optionally replace the activation step C of the substrate.

Step K .:

Advantageously, this rinsing step K, as well as the other rinsing steps which mark out the process, like step F or M, consist of bringing all or part of the surface of the substrate into contact with a or more source (s) of rinsing liquid, which are produced at different stages of the process of the invention, are produced by spraying an aerosol of rinsing liquid, preferably demineralized water.

• soit une seule solution contenant à la fois un ou plusieurs oxydant(s) et un ou plusieurs réducteur(s),
• soit deux solutions : la première contenant un ou plusieurs oxydant(s) et la seconde contenant un ou plusieurs réducteur(s),
• soit une pluralité de solutions, chacune pouvant contenir soit un ou plusieurs oxydant(s), soit un ou plusieurs réducteur(s), à la condition qu'il y ait au moins une solution oxydante et au moins une solution réductrice.

D.1 is a non-electrolytic metallization by aerosol spraying and relates in particular to the process described in FR2763962B1 , EP2326747B1 , or EP2318564B1 . The aerosol (or aerosols) is (are) eg:

• either a single solution containing both one or more oxidizing agent (s) and one or more reducing agent (s),
• either two solutions: the first containing one or more oxidizing agent (s) and the second containing one or more reducing agent (s),
• or a plurality of solutions, each of which may contain either one or more oxidizing agent (s) or one or more reducing agent (s), provided that there is at least one oxidizing solution and at least one reducing solution.

The reducing agent is advantageously strong enough to reduce the metal cation to metal, that is to say that the standard oxidation-reduction potential of the oxidizing / reducing couple of the reducing agent must be lower than that of the oxidizing / reducing couple of the oxidant ( gamma rule).
The redox solutions used during the non-electrolytic metallization step are sprayed in the form of aerosols on the substrate and are preferably obtained from solutions, advantageously aqueous, of one or more oxidizing metal cations and of one or more reducing compounds. These redox solutions are preferably obtained by dilution of concentrated stock solutions. The diluent is preferably demineralized water.
It follows that according to a preferred arrangement of the invention, the spraying aerosol (s) are produced by nebulization and / or atomization of solution (s) and / or dispersion (s), so in obtaining a mist of droplets of size less than 100 μm, preferably than 60 μm, and more preferably still from 0.1 to 50 μm.
In the method according to the invention, the projection of metallic solutions preferably takes place continuously and the substrate is set in motion and subjected to the projection. For example, when the metal deposit is silver-based, the projection is preferably continuous. For a nickel-based metal deposit, for example, the spraying is preferably carried out alternately with relaxation times.
In the process of the invention, the projection lasts from 0.5 to 200 seconds, preferably from 1 to 50 seconds and more preferably still from 2 to 30 seconds for a metallized surface of 1 dm2. The duration of projection has an effect on the thickness of the metal deposit and therefore on the opacity of this deposit. For most metals, if the projection time is less than 15 seconds, the deposit is qualified as semi-transparent and if the projection time is greater than 60 seconds, the deposit is qualified as opaque. The substrate can be rotated at least partially during the metallization spraying.

According to a first projection method, one or more solutions of metallic cation (s) and one or more solutions of reducing agent (s) are simultaneously sprayed onto the surface to be treated, in one or more aerosols. In this case, the mixture between the oxidizing solution and the reducing solution can be carried out just before the formation of the projection aerosol or even by melting an aerosol produced from the oxidizing solution and a aerosol produced from the reducing solution, preferably before coming into contact with the surface of the substrate to be metallized.

In accordance with a second projection method, one or more solutions of metallic cation (s) and then one or more solutions of reducing agent (s) are successively projected, via one or more aerosols. In other words, the projection of the redox solution is carried out by separate projection (s) of one or more solutions of one or more metal oxidants and of one or more solutions of one or more reducers. This second possibility corresponds to an alternating projection of the reducing solution (s) and of the metal salt (s).
In the context of the second spraying method, the association of several oxidizing metal cations to form a multilayer of different metals or alloys is such that the different salts are preferably sprayed naturally separately from the reducing agent but also separately the from each other and successively. It goes without saying that, in addition to the different nature of the metal cations, it is possible to envisage using counter-anions which are different from one another.

According to a variant of the spraying step, it is ensured that the mixture of the oxidant (s) and of the reducing agent (s) is metastable and, after spraying the mixture, the latter is activated so that the transformation into metal is triggered, of preferably by bringing into contact with an initiator, advantageously provided by means of one or more aerosols, before, during or after the projection of the reaction mixture. This variant makes it possible to premix the oxidant and the reducing agent while delaying their reaction until they cover the surface of the substrate after spraying. The initiation or activation of the reaction is then obtained by any appropriate physical (temperature, UV, etc.) or chemical means.

Beyond the methodological considerations presented above and illustrated below in the examples, some more precise information should be given as to the products used in the process according to the invention.
Water appears to be the best suitable solvent, without however excluding the possibility of using organic solvents for the production of solutions from which the sprayed aerosols will be produced.
The redox solutions projected during the metallization step of the substrate are one or more solutions of a metallic oxidant and one or more solutions of a reducing agent.
The concentrations of metal salts in the oxidizing solution to be sprayed are from 0.1 g / l to 100 g / l and preferably from 1 to 60 g / l, and the concentrations of metal salts in the stock solutions are from 0.5 g / l to 500 g / l, or else the dilution factor of the stock solutions is 5 to 5000. Advantageously, the metal salts are chosen from silver nitrate, nickel sulphate, copper sulphate and dichloride. tin, aurochloric acid, iron chloride, cobalt chloride and mixtures thereof.
The selection of reducing agents is preferably made from among the following compounds: borohydrides, dimethylaminoborane, hydrazine, sodium hypophosphite, formalin, lithium aluminum hydride, reducing sugars such as glucose derivatives or erythorbate sodium, and mixtures thereof. The selection of the reducing agent requires taking into account the pH and the properties targeted for the metallization film. These routine adjustments are within the abilities of those skilled in the art. The concentrations of reducing agent in the reducing solution to be sprayed are from 0.1 g / l to 100 g / l and preferably from 1 to 60 g / l, and the concentrations of reducing agent in the stock solutions are 0.5 g / l to 250 g / l, or else the dilution factor of the stock solutions is from 5 to 2500. According to a particular arrangement of the invention, particles are incorporated into at least one of the redox solutions in order to be projected at the time. metallization. The particles are thus trapped in the metal deposit. These hard particles are for example diamond, ceramic, carbon nanotubes, metal particles, rare earth oxides, PTFE (Polytetrafluoroethylene), graphite, metal oxides and their mixtures. The incorporation of these particles into the metallic film confers particular mechanical, tribological, electrical, functional and aesthetic properties on the metallized substrate.

D.2 : Metallization by immersion without current (electroless) (not in accordance with the invention)

It is possible that this step D is preceded by at least one of the following steps: step L (satin finish treatment of the surface of the substrate) and a step M (rinsing of the surface of the substrate).
This step L is in accordance with step I as described above in chapter D.1 relating to non-electrolytic metallization by spraying aerosols.
The same goes for the M.

This metallization D.2 is preferably carried out by immersing the substrate, preferably after removing the temporary protection, in an "electroless" bath containing the oxidizing and reducing species as well as the stabilizers and surfactants.
During this step, metallization takes place on all the zones catalyzed by the catalyst seeds (eg Palladium) adsorbed. The surface protected by the temporary protection (from preference eliminated during step E) is not catalyzed and therefore cannot be the site of metallization.
In the event that the temporary protective layer is not removed, it is advisable to implement a temporary protection on which the catalyst cannot be adsorbed and which is able to withstand the electroless bath, to prevent contamination of the latter. .
For more details on currentless immersion metallization, reference will be made to the examples which follow as well as to the numerous documents describing this technology, such as electroplating treatments.

D.3 : Electrolytic metallization in the case where the substrate is a conductive material (not in accordance with the invention)

For more details on this metallization, reference will be made to the numerous documents describing this technology.

Step E .: Removal of temporary protection

The elimination of the temporary protection can take place during, or at least partly during and after the metallization step D, or in part during and after the metallization step D and in part before the metallization step D.
The elimination of the temporary protection, at least in part during the metallization, supposes that the means employed in the latter allow it and that the residue produced by this elimination is not of a nature to thwart the metallization. This is particularly the case for metallization by spraying aerosols.
The elimination of the temporary protection after metallization will have its place in the case where the metallization means, for example metallization solutions, are not able to dissolve the temporary protection; as in metallization by spraying aerosols with certain metals such as nickel, for example.
According to the invention, this elimination is dissolution in a solvent used in the process.

According to another possibility of the invention, the method comprises a rinsing step F, and step E of removing the temporary protection is carried out partly during step D and at least partly during step F.

According to another possibility of the invention, the method comprises a step G of drying, and step E of removing the temporary protection is carried out partly during step D and at least partly during step G.

E.1 : Metallization by aerosol spraying

In this mode of implementation, the elimination of the temporary protection can take place during the metallization step. In such a case, it is important that at least one of the metallization solutions include a solvent for the temporary protection.
In practice, and even more preferably, the temporary protection is alkali-soluble (eg ink) the metallization solutions have a strongly alkaline pH, which allows them to solubilize this temporary protection.
During the projection of the metallization solutions, the unprotected areas are metallized while the protective layer is solubilized and discharged into the effluents, thus allowing the metallic patterns to appear.
It is preferable that the duration of metallization is limited so as to prevent any possibility of metallization on the areas initially covered by the temporary protection.
In this mode of implementation, for metals not requiring activation (eg Nickel), it is possible to rinse, for example by spraying, the surface of the substrate comprising the targeted metal patterns and the temporary protection itself covered with 'a layer of metal, using solvents for this temporary protection. The dissolution of the latter is accompanied by the evacuation of the metal layer with which it is coated.

E.2 : Metallization by immersion without current

Before the metallization, a suitable solution, that is to say one containing a solvent for the temporary protection, is therefore applied to the surface of the substrate. This can be done, for example, by immersion followed by rinsing. This dissolution reveals the areas of the surface of the substrate corresponding to the negative of the metallic patterns to be produced.
Since the deprotected areas of the surface are not activated (adsorption of the catalyst), they do not allow initiation of metallization for a sufficient period of time to form metal patterns. The term “sufficient time” is understood to mean the time required for the formation of metallic patterns on the activated zones of the surface of the substrate.

Step F: Rinsing

In accordance with the invention, the rinses which mark the separations between the various deposits involved in the process are carried out in a known and appropriate manner, for example by spraying / spraying rinsing liquid or immersing in a rinsing liquid. The latter is advantageously and preferably water, and more particularly demineralized water.

Step G: Drying / Blowing

The drying or blowing, which can take place in particular after each rinsing step, consists in the evacuation of the rinsing water. It can advantageously be carried out at a temperature of 20 at 60 ° C using, for example, a pulsed compressed air system at eg 5 bars / pulsed air, at a temperature of 20 to 60 ° C. Drying in the open air or in an oven are also possible.

Step H .: finishing treatment on the surface of the substrate bearing the metallic patterns

To strengthen the protection of the metal patterns vis-à-vis external aggressive agents and / or to strengthen the electrical conduction of the metal patterns, it can be provided in accordance with the invention to continue the metallization ("post-metallization") with au at least one metal identical or different to the metal of the metallization step D, preferably by electrolytic thickening.
A finishing treatment variant may be the deposit of at least one topcoat of a crosslinkable liquid composition on the surface of the substrate bearing the metallic patterns. This liquid composition crosslinkable on the protective layer is for example a paint or a varnish, preferably a finishing varnish. This varnish can be based on water-soluble or organic, preferably organic. It is chosen from the paints of the following group: alkyds, polyurethanes, epoxies, vinyls, acrylics and their mixtures. Preferably, it is chosen from the following compounds: epoxies, alkyds and acrylics and, more preferably still, it is an alkyd varnish. The crosslinkable liquid finishing composition can be crosslinked by UV or thermal curing and can contain pigments or dyes for coloring.
In the process according to the invention, the effluents resulting from the various stages of the process are advantageously reprocessed and recycled to be reused in the process, and to limit the ecological impact.

The advantages of the process according to the invention are numerous:
It is about a selective deposit of metallic patterns likely to be fine & complex, on an industrial scale with a high productivity, while allowing an excellent adhesion and a very great resistance of the metallic patterns towards external aggressions, and this over long periods.

The flexibility and the graphic, ornamental and functional possibilities offered by this process for producing metallic patterns on any type of substrate are extremely important.

• de décoration ou de marquages métallisés d'objets par des informations figuratives et/ou scripturales d'identification,
• et de fabrication d'organes fonctionnels dans des dispositifs électroniques tels que des circuits imprimés des circuits intégrés sur un substrat semi-conducteur, des puces de radio-identification, des pictogrammes codant lisibles par des lecteurs électroniques...

In addition, the process according to the invention gives access to new industrial processes:

• decoration or metallic markings of objects with figurative and / or scriptural identification information,
• and manufacturing functional components in electronic devices such as printed circuits, integrated circuits on a semiconductor substrate, radio-identification chips, coding pictograms readable by electronic readers, etc.

The invention therefore provides in so doing these new advantageous industrial processes, integrating the technique of selective deposition of metallic units described and claimed here.

• la figure 1 représente un schéma illustrant les procédés de photolithographie connus pour la fabrication de circuits imprimés.
• la figure 2 représente un schéma illustrant le protocole des exemples 1 et 2 mettant en œuvre le procédé selon l'invention avec une métallisation par projection d'aérosol ;
• la figure 3 représente le masque de sérigraphie de l'exemple 1 ;
• la figure 4 représente les motifs métalliques obtenus dans l'exemple 1 ;
• la figure 5 représente le masque de sérigraphie de l'exemple 2 ;
• la figure 6 représente les motifs métalliques obtenus dans l'exemple 2 ;

The invention will be better understood on reading the following description of examples of manufacturing metal patterns on different supports, with reference to the appended drawings in which:

• the figure 1 is a diagram illustrating known photolithography processes for the manufacture of printed circuits.
• the figure 2 represents a diagram illustrating the protocol of Examples 1 and 2 implementing the method according to the invention with metallization by aerosol spraying;
• the figure 3 represents the screen printing mask of Example 1;
• the figure 4 represents the metal units obtained in Example 1;
• the figure 5 represents the screen printing mask of Example 2;
• the figure 6 represents the metal units obtained in Example 2;

Example 1: Production of metallic patterns (silver) on a varnished plastic substrate for decorative purposes

• • -A- Surface preparation:
  A reference UV crosslinking varnish VB330R developed by the company JetMetal Technologies® is applied using an HVLP pneumatic gun with an air pressure of between 3 and 4 bars on an ABS (Acrylonitrile Butadiene Styrene) plate of dimensions 25cm x 20cm degreased beforehand.
  The applied plate undergoes desolvation in an oven at 60 ° C. for 5 minutes before polymerization in a UV chamber (0.7 to 1.2J / cm ² UVA).
• • -B- Deposit of temporary protection:
  A film of the soluble alkali product Propaco SC marketed by the company SOCOMORE containing an alkali-soluble binder, quick-drying is affixed to the varnished plate through a screen printing mask corresponding to the negative of the metallic pattern to be produced. This mask is shown on the Fig. 3 annexed. The lighter areas allow the soluble alkali / ink product to pass through to form the temporary protection.
• • -I-Surface energy increase treatment:
  Flaming by rapid passages for a total duration of 5s using a flamer whose flame temperature has been set to 1400 ° C (After flaming, the substrate must have a surface energy greater than 50 dynes).
  After the flaming step, the unprotected surface must be wetting in its entirety (the projection of water on the surface results in the formation of a continuous liquid film).
• • -C-Activation / awareness:
  Projection of a sensitizing solution based on stannous chloride for 10s using HVLP guns.
• • -K-rinse:
  Rinsing of the sensitization solution by spraying demineralized water for 10s using an HVLP gun
• • -D-Metallization / -E- elimination of temporary protection:
  Simultaneous projection of an aqueous solution based on silver nitrate of concentration of 2g / L having an alkaline pH of 11.2 + - 0.2 with an aqueous solution based on glucose for 40s using HVLP guns
  • Metallization takes place on non-inked areas
  • The ink film is evacuated in contact with the metallization solutions
• • -F- Rinsing:
  Rinsing with demineralized water for 10s by projection using an HVLP gun
• • -G- Drying / Blowing:
  Drying / Blowing by alternating compressed air pulsed at 5 bars at room temperature
• • -H-Finish:
  The plate thus metallized is varnished by projection using an HVLP gun and a reference varnish VM112 developed by the company JetMetal Technologies®.
  The wafer undergoes desolvation in an oven at 60 ° C. for 5 minutes before polymerization in a UV chamber (0.7 to 1.2J / cm ² UVA).

Metallic silver patterns are thus obtained corresponding to the negative of the ink initially deposited - see Fig. 4 appended- (The non-metallized parts correspond to the areas covered by the screen printing ink)

Example 2: Production of an electronic unit on a rigid polymer substrate

• • -B- Deposit of temporary protection:
  A film of the alkali-soluble product Propaco SC marketed by the company SOCOMORE containing an alkali-soluble binder, quick-drying is affixed to an ABS plate of dimensions 25cm x 20cm through a screen printing mask corresponding to the negative of the pattern to be made. This mask is shown on the Fig. 5 attached, in which the lighter areas allow the soluble alkali / ink product to pass through to form the temporary protection.
• • -I-Surface energy increase treatment:
  A flaming of the surface is carried out by rapid passages for a total duration of 5s using a flamer whose flame temperature has been set to 1400 ° C (After flaming, the substrate must have a surface energy greater than 50 dynes). After the flaming step, the unprotected surface must be wetting in its entirety (the projection of water on the surface causes the formation of a continuous liquid film)
• • -C-Activation / awareness:
  Spraying of a sensitizing solution based on stannous chloride for 10s using HVLP guns
• • -K-rinse:
  Rinsing with water for 10s by projection using an HVLP gun
• • -D-Metallization / -E- elimination of temporary protection:
  Simultaneous projection of an aqueous solution having an alkaline pH of 11.5 + - 0.2 based on silver nitrate with a concentration of 2g / L with an aqueous solution based on glucose for 25s using HVLP guns.
  Metallization takes place on non-inked areas
  The ink film is evacuated in contact with the metallization solutions
• • -F- Rinsing:
  Rinsing with demineralized water for 10s by projection using an HVLP gun
• • -G- Drying / Blowing:
  Drying by alternating pulsed compressed air at 5 bars at room temperature.

A conductive circuit is thus obtained corresponding to the negative of the ink deposited initially - see Fig. 6 annexed - (The non-metallized parts correspond to the areas covered by the screen printing ink).
The silver deposit is sufficiently conductive to achieve an electrolytic thickening of copper with a conventional bath of acidic copper based on copper sulfate and sulfuric acid.

Example 3: Online production of decorative metal patterns by inkjet printing

• The polypropylene plastic part (cylinder 2.5cm in diameter and 8cm high) is attached to the inverted conveyor on the ground.
• The conveyor is started at a constant speed of 3m / min and the part is rotated at 350 rpm.
  • • -A- Surface preparation:
    The part is degreased by rubbing with isopropanol alcohol, then applying a base coat of UV crosslinking varnish, reference VB330R, containing a rate of 3% of red dye from the company JetMetal Technologies using 3 HVLP guns. The PP part moves in a thermal oven at 50 ° for a de-solvation step for 4 min then passes into a UV oven where the surface of the part is irradiated with a power of 0.9J / cm ² .
  • • -I-Surface energy increase treatment:
    Flaming of the rotating part is carried out on the conveyor by rapid passages for a total duration of 5s using a flame whose flame temperature has been set to 1400 ° C (After flaming, the substrate must present a surface energy greater than 50 dynes).
    After the flaming step, the entire surface must be wetting (splashing water on the surface results in the formation of a continuous liquid film).
  • • -B- Deposit of temporary protection:
    On the rotating part, inkjet printing using a Ricoh Gen4 printhead is performed in-line (without unloading the part from the conveyor) using an alkali-sensitive TIGER Heavy Duty Ink containing an alkali binder sensitive.
    This ink is crosslinked by UV exposure using a mercury bulb with a power of 40 mJ / cm ² .
    This print corresponds to the negative of the desired pattern.
    The film-forming agent contained in the ink guarantees the masking of the surface; the pigments are not essential for the correct functioning of the process.
  • • -C-Activation / awareness:
    Projection of a sensitizing solution based on stannous chloride for 5s using HVLP guns.
  • • -K-rinse:
    Rinsing of the sensitization solution by spraying demineralized water for 10 s using an HVLP gun.
  • • -D-Metallization:
    Simultaneous projection of an aqueous solution based on silver nitrate with a concentration of 2g / L having an alkaline pH of the order of 11.2 + -0.2 with an aqueous solution based on glucose for 20s using HVLP guns.
    The metallization takes place on the non-inked areas.
    The adhesion of the alkali-sensitive ink film is affected upon contact with solutions for
    metallization.
  • • -F- Rinsing / -E- removal of temporary protection:
    Rinsing with demineralized water for 20s by projection using HVLP guns.
    The ink, the adhesion of which was affected during the metallization step, is discharged during this rinsing.
  • • -G- Drying:
    Drying by alternating pulsed compressed air at 5 bars at room temperature using an air knife.
  • • -H-Finish:
    The plate thus metallized is varnished by projection using an HVLP gun and a reference varnish VM112 developed by the company JetMetal Technologies®.
    The wafer undergoes desolvation in an oven at 60 ° C. for 5 minutes before polymerization in a UV chamber (0.7 to 1.2J / cm ² UVA).

Metallic decorative silver patterns with a mirror effect are thus obtained corresponding to the negative of the ink deposited initially. The non-metallic areas reveal the color of the red base varnish. The pictogram characters can be made in order to show the name of a brand or a logo.

Example 4: Realization of a silver pattern with electrolytic copper thickening in line

• • -B- Deposit of temporary protection:
  A quick-drying LINX 1070 alkali-soluble ink film is affixed by inkjet spraying (Seiko head) on a flexible polyimide film 75 µm thick placed flat on a conveyor fitted with a rewinder / unwinder .
  The inked pattern corresponds to the negative of the pattern to be made.
• • -I-Surface energy increase treatment:
  In order to confer increased adhesion of the metal deposit with the substrate, an atmospheric plasma pretreatment (rotary plasma head) was applied (after plasma treatment, the substrate must have a surface energy greater than 50 dynes).
  After the plasma step, the entire surface should be wetting (splashing water on the surface results in the formation of a continuous liquid film).
• • -C-Activation / awareness:
  Projection of a sensitizing solution based on stannous chloride for 5s using HVLP guns.
• • -K-rinse:
  Rinsing of the sensitization solution by spraying demineralized water for 10 s using an HVLP gun.
• • -D-Metallization / -E- elimination of temporary protection:
  Simultaneous projection of an aqueous solution based on silver nitrate with a concentration of 2g / L having an alkaline pH of the order of 11.2 + -0.2 with an aqueous solution based on glucose for 20s using HVLP guns.
  The metallization takes place on the non-inked areas.
  The ink film is solubilized and evacuated during the metallization in contact with the solutions.
• • -F- Rinsing:
  Rinse with demineralized water for 10s by projection using an HVLP gun.
• • -H-Finish:
  The film with silver pattern is then guided by the conveyor of a tank containing an acidic copper bath based on copper sulfate and sulfuric acid at 20 ° C in order to undergo an electrolytic copper thickening of 10 μm.
  The polyimide film is connected on one of the silver zones to a cathodic contact placed opposite the soluble copper anodes.
  A current density of 3A / dm ² allows a copper deposit of 10µm to be produced in 20 minutes.
• • -F- Rinsing:
  Rinsing demineralized water by immersion for 30s.
• • -G- Drying:
  Drying by alternating pulsed compressed air at 5 bars at room temperature.

Over the entire process, the polyimide film is unwound at the start of treatment, undergoes each step and is then wound up again at the end of the process.

Claims (11)

1. Process for producing metal patterns on a substrate, comprising the essential following steps:

   A. optionally preparing the surface of the substrate intended to receive the metal patterns;

   B. depositing a temporary protection on the surface of the substrate corresponding to the negative of the patterns to be produced by means of a screen printing mask/stencil the cut-outs of which correspond to the negative of the patterns to be produced; and/or by direct printing, preferably by ink jet;

   C. optionally activating the surface of the substrate, in particular the areas corresponding to the patterns to be produced;

   D. metallization by depositing at least one metal on the areas corresponding to the patterns to be produced;

   E. eliminating the temporary protection of step B;

   F. optionally rinsing the surface of the substrate carrying the metal patterns;

   G. optionally drying the surface of the substrate carrying the metal patterns;

   H. optionally finishing treatment on the surface of the substrate carrying the metal patterns;

   • characterized in that step E of eliminating the temporary protection is carried out during step D, or at least partly during step D and after step D, or at least partly during and after the metallization step D and partly before the metallization step D,

   • in that step E essentially consists in the dissolution of the temporary protection by at least one solvent contained in at least one metallisation solution, said solvent being preferably alkaline and said temporary protection being preferably alkali-soluble so that it can be dissolved preferably by said solvent,

   • in that the metallic deposition D is a non-electrolytic metallization by spraying of one or more redox solutions in the form of (an) aerosol(s).

   • and in that it optionally comprises, before the metallization D, at least one of the following steps, preferably in the following order:

   I. treatment increasing the surface energy of the substrate, in the knowledge that in the event that the process comprises an activating step C, a step I of increasing the surface energy of the substrate can optionally be provided before the activation C.

   J. wetting the surface of the substrate;

   K. rinsing the surface of the substrate.
2. Process according to claim 1, characterized in that step E further comprises at least one of the following operations:

   • entrainment in liquid phase;

   • mechanical entrainment by a gas, preferably air.
3. Process according to claim 1, characterized in that the metal of step D is selected from the following group of metals: silver, nickel, tin, iron, gold, cobalt, copper; oxides, alloys and combinations thereof.
4. Process according to claim(s) 1 to 3, characterized in that it comprises a step A, which comprises the deposition of at least one layer of varnish and/or the degreasing of the surface of the substrate intended to receive the metal patterns.
5. Process according to at least one of claims 1 to 4, characterized in that the treatment for increasing the surface energy of the substrate according to step I is selected from the physical treatments, preferably the following physical treatments: a flame treatment, a plasma treatment and combinations thereof, and/or chemical treatments, preferably the following chemical treatments: application of a silane-based solution, depassivation of the surface using one or more acid solutions, polishing based on a rare-earth oxide, fluorination and combinations thereof.
6. Process according to claim(s) 1 to 5, characterized in that the finishing treatment H is the production of one or more coats of varnish and/or an electrolytic thickening composed of one or more metals.
7. Process according to claim 1 to 6, characterized in that the solvent allowing the dissolution of the temporary protection is also contained in the liquids used in at least one rinsing step and in that the duration of the metallization step D is preferably less than or equal to the duration of dissolution of the temporary protection.
8. Process according to at least one of the preceding claims, characterized in that the metal patterns obtained are decorative and/or functional, and are preferably included in the group comprising - preferably constituted by: printed circuits, integrated circuits on a semiconductor substrate, radio frequency identification (RFID) chips, coding icons capable of being read by electronic devices, representational and/or written information identifying a product, in particular a commercial product, such as a decorative visual representation or design on a cosmetic and/or automotive product.
9. Process according to at least one of the preceding claims, characterized in that it is implemented continuously/in-line on industrial plant.
10. Process for the manufacture of objects comprising metal patterns, preferably decorative and/or functional, characterized in that it implements the process according to at least one of the preceding claims.
11. Set of consumables for implementing the process according to at least one of the preceding claims, characterized in that it comprises:

    a. (a) consumable(s) for carrying out the temporary protection of step B; said temporary protection being soluble in an alkaline solvent;

    b. (a) consumable(s) for the metallization of step D; comprising one or more redox solutions containing one or more oxidant metallic cations and one or more reducing compounds, at least one of the said solutions containing an alkaline solvent,

    c. optionally, (a) consumable(s) for preparing the surface of the substrate intended to receive the metal patterns of step A; and/or;

    d. optionally at least one screen printing mask/stencil useful in one of the variants of step B; and/or;

    e. optionally (a) consumable(s) for activating the surface of the substrate of step C; and/or;

    f. optionally (a) consumable(s) for eliminating, according to step E, the temporary protection of step B; and/or;

    g. optionally (a) consumable(s) for rinsing according to step F; and/or;

    h. optionally (a) consumable(s) for depositing at least one top coat according to step H.

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