JP7455859B2 - Method of activating the surface of a non-conductive or carbon fiber-containing substrate for metallization - Google Patents

Description

The present invention relates to activating the surface of typically non-conductive or carbon fiber-containing substrates for subsequent metallization.

In particular, the present invention provides a method for activating the surface of a non-conductive substrate or a carbon fiber-containing substrate for metallization; A method for preparing a palladium-free aqueous activation composition for activating the surface of a non-conductive or carbon fiber-containing substrate for metallization; A palladium-free aqueous activation composition for activating the surface of a substrate for metallization.

Typically, metallization of such substrates is of high commercial interest. In many aspects of everyday life, such substrates are coated with metallic structures or layers, either for decorative or functional applications. For example, non-conductive plastic substrates are typically used in the manufacture of sanitary articles with shiny chrome layers. Furthermore, the automotive industry also uses a large number of plastic substrates coated with chromium.

In addition to such decorative articles, functional metallization is essential, for example in the production of printed circuit boards. Such substrates typically use a non-conductive resin-containing laminate as the base material, which usually includes a circuit of copper wires.

Carbon fiber-containing substrates have increasing potential as catalytically active surfaces, for example, in power-to-gas, power-to-fuel, and power-to-chemical applications, and in batteries.

All of these applications require a typically multi-step preparation of the non-conductive or carbon fiber-containing substrate to render it amenable to subsequent metallization.

The first step typically involves cleaning the surface of the non-conductive or carbon fiber-containing substrate, for example to remove grease or impurities.

The second step typically involves pre-treating or conditioning the surface in order to make it receptive to subsequent activation. Such pretreatment may include, for example, etching to create pores and increase surface area.

In the third step, an important activation takes place. Such activation typically involves depositing/fixing a very thin seed layer or activation layer on the surface of a non-conductive or carbon fiber-containing substrate, which is followed by a first metallization layer. Act as a starting point for. The result is an activated surface for metallization. The seed layer or activation layer typically acts as a mediator between the surface of the non-conductive or carbon fiber-containing substrate and one or more subsequent metallization layers. Typically, the seed layer/activation layer is formed by depositing metal nanoparticles onto the surface, eg from a colloidal activation composition.

In a fourth step, typically the first metallization layer is deposited on the seed layer/activation layer, most commonly by electroless plating. In some cases, this electroless plating involves immersion type plating, ie, deposition of more precious metal onto the seed layer/activation layer in the absence of a reducing agent by an exchange reaction. In other cases, it involves the deposition of metals or metal alloys by autocatalytic deposition, which means that the deposition is promoted by a reducing agent.

In a fifth step, a second metallization layer is typically deposited on the first metallization layer, again by autocatalytic deposition or by electrodeposition.

Basically, a person skilled in the art is familiar with such a series of steps. Typically, nanoparticles of noble metals, and very often palladium, are utilized in common colloidal activation compositions. However, precious metals are generally expensive and wastewater treatment to reuse residual precious metals is a strong concern. Alternatively, cheaper metal ions are increasingly utilized in each activation composition.

Another common drawback is that such activated compositions naturally undergo some type of degradation or decomposition. Typically, the nanoparticles aggregate to form insoluble precipitating aggregates, rendering the composition nearly unusable. Therefore, it is typically desirable to stabilize the nanoparticles after they are formed by reduction of each metal ion. To this end, stabilizer compounds are typically used to modify the charge distribution of the particles, limit the particle size, and/or prevent oxidation of the particles. Often polymers and/or antioxidants and/or metal ions (such as tin ions) are used for these purposes.

For example, Chinese Patent No. 107460459(A) relates to a simple nano-copper activation solution with stabilizers and reducing agents to prevent agglomeration and oxidation of nanoparticles, respectively.

U.S. Pat. No. 4,278,712 discloses a method for activating weakly active colloidal dispersions that are useful in preparing nonconductors prior to electroless plating. This method is based on the controlled oxidation of colloids, which are weakly active as such, by treatment with suitable gases and/or chemical agents that bring about said controlled oxidation. However, the presence of at least one colloidal stabilizer is essential. In this method, no reversible equilibrium is maintained.

Techniques such as those described in the art typically have the disadvantage of being prone to sooner or later agglomeration and precipitation, the main reason being that the stabilizer compound does not sufficiently stabilize the particles over time. Because they don't. As a result, product life depends very strongly on production date and time, time of delivery, and quality of stabilization.

Furthermore, it is believed that such stabilizer compounds often reduce the ability of the nanoparticles to effectively activate their respective surfaces. The additives appear to, on the one hand, avoid agglomeration at least to some extent, but on the other hand, inhibit the rapid and strong adsorption of these particles onto the surface.

Chinese Patent No. 107460459(A) U.S. Patent No. 4,278,712

It is therefore an object of the present invention to provide a method and respective activation compositions for activating the surface of non-conductive substrates or carbon fiber-containing substrates for metallization, which compositions, on the one hand, It is simple and highly effective, and on the other hand, it is particularly resistant to agglomeration and precipitation, ensuring a long shelf life. Furthermore, such methods and respective compositions should be low cost.

Another aim of the invention was to provide methods with reduced environmental impact, for example those involving less sophisticated wastewater treatment and reduction of the effective concentration of chemicals.

Furthermore, it was an object of the present invention to provide methods in which the lifetime is extended, especially for the activated compositions utilized.

The object mentioned above is a method for activating the surface of a non-conductive substrate or a carbon fiber-containing substrate for metallization, comprising:
(a) preparing the base material;
(b)
(i) a first species of dissolved transition metal ions and additionally metal particles thereof;
(ii) one or more complexing agents;
(iii) one or more reducing agents, permanently or temporarily;
(iv) optionally providing a palladium-free aqueous activation composition comprising one or more dissolved metal ions of a second species different from the first species;
- at least a first species of dissolved transition metal ions and metal particles thereof exist in reversible equilibrium, with the proviso that
- the metal particles are formed from dissolved transition metal ions by continuous or semi-continuous reduction with one or more reducing agents,
- dissolved transition metal ions are formed from the metal particles by continuous or semi-continuous oxidation of said particles, and - dissolved transition metal ions and their metal particles, respectively, do not form precipitating agglomerates of said metal particles. As such, it repeatedly participates in the reduction and the oxidation.
process,
(c) contacting the substrate with the activating composition such that a transition metal or transition metal alloy is deposited on the surface of the substrate to provide an activated surface for metallization; Solved by method.

The inventor's own experiments have shown that in the present invention a very simple and effective activation is achieved without even the need for a high degree of stabilization/antioxidation of the particles formed. In contrast to common activated compositions, it has been found that no stabilization/antioxidation of the particles formed is required. This means that, in the present invention, particles are not formed with the goal of maintaining as much as possible, but rather that an equilibrium state is established between the dissolved transition metal ions and each of its particles; /means intentionally formed to enable its respective ions to be repeatedly reformed by oxidation. Typically, in common activation compositions, oxidation is minimized and/or suppressed because it is considered harmful. In contrast, in the present invention, oxidation is advantageously utilized and is considered necessary and highly beneficial. Contrary to popular opinion, it has been found that it is not necessary to maintain the particles in each activated composition for an extended period of time.

This brings many advantages. For example, in a very convenient manner, each activation composition is easily set up/activated at the site where it is needed by simply adding the required reducing agent. This means that the product delivery time is independent of the product/method lifetime.

The present invention relies on the particles being repeatedly formed in situ, thereby eliminating the need for any stabilization or stabilizer compounds. Therefore, dissolved transition metal ions and their metal particles exist in a reversible equilibrium state. As a result, a very effective and strong activation can be achieved since relatively short-lived fresh particles are formed without a surrounding shell of stabilizer compound. The particles then return to their ionic form by an oxidation reaction. Upon addition of further reducing agent, fresh particles are formed again, i.e. in situ.

In the method of the invention, a transition metal or transition metal alloy is deposited on the surface of the substrate to provide an activated surface for subsequent metallization. This means that the concentration of dissolved metal ions of the first species decreases over time due to deposition. However, replenishment of the first species is easily achieved by simply adding ions of that species. Therefore, replenishment is extremely easy and convenient. This further greatly extends the lifetime of each activation composition and its associated methods.

Furthermore, each method and activation composition does not necessarily require expensive noble metals and can be performed with inexpensive transition metals.

In the context of the present invention, "continuous", "continuously", and "continuously" each mean, for example, each act during each method or embodiment of the invention is performed with a significant degree of It means that it occurs continuously without any interruption.

In the context of the present invention, "semi-continuous," "semi-continuously," and "semi-continuously" each refer to, for example, the respective actions occurring while each method or aspect of the invention is being carried out. , meaning that it occurs with one or more interruptions of action, or even with significant interruptions. The interruption is sometimes longer than the time the effect is occurring. It even includes mere temporary short-term effects.

In the context of the present invention, "species" (eg, first species or second species) means a chemical element. Accordingly, "dissolved transition metal ion of the first species" means a dissolved metal ion of a transition metal element of groups 3 to 12 of the periodic table, such as copper.

In the context of the present invention, "a first species of dissolved transition metal ions and additionally metal particles thereof" refers to this first species of dissolved transition metal ions and, for example, in a palladium-free aqueous activation composition. It additionally means metal particles of this first type.

Base material:
In step (a) of the method (for activation) of the invention, a non-conductive or carbon fiber-containing substrate having a surface is provided. Activation is necessary since such substrates are inherently not capable of good metallization.

In the context of the present invention, activation means that after each activation step the surface of a non-conductive substrate or a carbon fiber-containing substrate is made of a transition metal with sufficient adhesion for subsequent metallization. or modified in such a way as to include a transition metal alloy. Furthermore, the deposited transition metals and transition metal alloys each adhere well to the surface such that a subsequent metallization layer can (i) be deposited thereon, and (ii ) Overall, it also adheres well to the surface of a non-conductive substrate or a carbon fiber-containing substrate.

Preferred is the method (for activation) of the invention, wherein the non-conductive substrate is preferably selected from the group consisting of plastics, resin-containing laminates, glasses, ceramics, semiconductors, and mixtures thereof.

Preferred plastics include thermoplastics, preferably thermoplastics, more preferably polyacrylates, polyamides, polyimides, polyesters, polycarbonates, polyalkylenes, polyphenylenes, polystyrenes, polyvinyls, or mixtures thereof, preferably are them.

Preferred polyacrylates include poly(methyl methacrylate) (PMMA).

Preferred polyimides include polyetherimide (PEI).

Preferred polyesters include polylactic acid (PLA).

Preferred polycarbonates include polycarbonates (PC) obtained using bisphenol A.

Preferred polyalkylenes include polyethylene (PE), polypropylene (PP), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), or mixtures thereof.

Preferred polyphenylenes include poly(phenylene oxide) (PPO), poly(phenylene ether) (PPE), or mixtures thereof.

Preferred polystyrenes include polystyrene (PS), acrylonitrile butadiene styrene (ABS), styrene/butadiene rubber (SBR), and styrene-acrylonitrile (SAN).

Preferred polyvinyls include polyvinyl chloride (PVC), poly(ethylene-vinyl acetate) (PEVA), polyvinylidene fluoride (PVDF), or mixtures thereof.

Preferred resin-containing laminates include, and are preferably fiber-reinforced resin-containing laminates, most preferably glass fiber-reinforced laminates.

Very preferably, the resin-containing laminate comprises one or more polymers of epoxy, vinyl ester, polyester, amide, imide, phenol, alkylene, sulfone, or mixtures thereof, most preferably epoxy, imide, Alternatively, one or more of these mixtures of polymers may be contained as a resin.

A highly preferred resin-containing laminate comprises FR4, preferably FR4.

Preferred glasses include silica glass, soda lime glass, float glass, fluoride glass, aluminosilicate glass, phosphate glass, borate glass, borosilicate glass, chalcogenide glass, aluminum oxide glass, or mixtures thereof; Preferably those.

Preferred ceramics include, preferably glass ceramics, aluminum oxide ceramics, or mixtures thereof.

Preferred semiconductors include silicon-based semiconductors, more preferably silicon-based semiconductors containing silicon dioxide and/or silicon.

A highly preferred semiconductor is a wafer.

The method (for activation) of the invention, wherein the carbon fiber-containing substrate comprises a carbon fiber composite and/or an array of carbon fiber filaments, preferably an array of carbon fiber composites and/or carbon fiber filaments. preferable.

Preferred carbon fiber composites include carbon fiber-reinforced polymers and/or carbon fiber-containing fabrics, more preferably carbon fiber-reinforced polymers and/or carbon fiber-containing woven fabrics, and are preferably these.

Preferred carbon fiber filament arrangements include and are preferably fabrics made from carbon fibers, most preferably woven fabrics made from carbon fibers.

A particularly preferred carbon fiber-containing substrate is carbon fiber-containing felt.

Preprocessing:
In some cases, it is preferable to pre-treat the surface of the non-conductive substrate or carbon fiber-containing substrate. Therefore, before step (c), a pretreatment step of the substrate:
(a-1) treating the base material with a pretreatment solution containing a nitrogen-containing compound;
Preferred are methods (for activation) of the invention comprising:

The pretreatment solution has an alkaline pH, preferably in the range of 9.0 to 14.0, more preferably in the range of 10.0 to 13.5, even more preferably in the range of 10.5 to 13.0. Preferably, the method (for activation) of the present invention has a pH within the range, most preferably within the range 11.0 to 12.5.

Preference is given to the method of the invention (for activation) in which the nitrogen-containing compound in the pretreatment solution is a polymer, preferably a water-soluble polymer.

More preferred is the method of the invention (for activation) in which the nitrogen-containing compound in the pretreatment solution is a polymer containing a pyrrolidine moiety.

Preferably the polymer is cationic.

Preferably, the nitrogen-containing compound consists of carbon, nitrogen, and hydrogen atoms.

Preference is given to the method of the invention (for activation) in which the nitrogen-containing compound in the pretreatment solution contains quaternary nitrogen atoms.

Most preferred is the method (for activation) of the invention in which the nitrogen-containing compound comprises polyquaternium-6, preferably polyquaternium-6.

During step (a-1), the pretreatment solution is in the range of 20°C to 90°C, preferably in the range of 25°C to 80°C, more preferably in the range of 30°C to 70°C, most preferably 40°C. Preference is given to a method (for activation) of the invention having a temperature in the range from 0.degree. C. to 60.degree.

In the present invention, step (a-1) is carried out for 1 minute to 10 minutes, preferably 2 minutes to 8 minutes, more preferably 3 minutes to 6 minutes, most preferably 3.5 minutes to 5 minutes. ) method is preferred.

Palladium-free aqueous activation composition:
In step (b) of the method (for activation) of the invention, a palladium-free aqueous activation composition is provided.

The aqueous composition utilized in the method (for activation) of the present invention is an aqueous composition, meaning that water is a major component. Thus, based on the total weight of the aqueous composition, more than 50% by weight of the composition is water, preferably at least 70% by weight, even more preferably at least 90% by weight, most preferably 95% by weight or more by weight. be. Only in rare cases will it be preferable for the composition to contain one or more solvents (other than water) that are miscible with water. However, water is the only solvent, and therefore, most preferably (for environmental protection reasons) methods in which the composition is substantially free or completely free of organic solvents.

In the context of the present invention, the term "substantially free or free" with respect to a target substance (e.g., a compound, chemical, material, etc.) independently means that said target substance is not present at all (``contains no ("substantially free"), or present only in such a small and non-interfering amount that it does not affect the intended purpose of the invention ("substantially free"). For example, such a target substance may be added or utilized unintentionally, for example, as an unavoidable impurity. "Substantially free or free" preferably means from 0 ppm to 5 ppm, preferably from 0 ppm to 3 ppm, more preferably from 0 ppm to 1.5 ppm, for example based on the total weight of the activated composition. , even more preferably 0 ppm to 1 ppm, most preferably 0 ppm to 0.5 ppm, even more preferably 0 ppm to 0.1 ppm. This principle applies equally to other target substances, for example the total mass of transition metals or transition metal alloys obtained in step (c) of the method (for activation) of the invention.

The activating composition has an acidic pH, a neutral pH, or an alkaline pH, preferably an acidic or neutral pH, and most preferably an acidic pH.

The pH of the activation composition is within the range of 2.0 or more and 13.0 or less, preferably 3.0 or more and 12.0 or less, more preferably 4.0 or more and 11.0 or less. Among these, the method (for activation) of the present invention is most preferably in the range of 4.5 or more and 10.0 or less.

Optionally, the pH of the activation composition of the present invention (for activation) is within the range of 3.0 or more and 6.5 or less, preferably 4.0 or more and 6.0 or less. ) method is preferred. Preferably, this is the case with the proviso that the one or more reducing agents comprise a borohydride.

The pH of the activated composition is typically a result of the presence of (i)-(iv). If pH adjustment is necessary, it is done by typical means. Preferred acids are inorganic and organic acids. A preferred inorganic acid is sulfuric acid. Preferred organic acids are the acid form of one or more complexing agents. Preferred alkaline compounds are alkali hydroxides, preferably NaOH, alkali carbonates, preferably sodium carbonate, and ammonia.

In the context of the present invention, pH is determined at a temperature of 20°C, ie the pH defined is based on 20°C. Therefore, for pH determination purposes only, the activated composition has a temperature of 20°C. This does not mean that the activation composition itself is limited to a particular temperature of 20°C. See below for preferred temperatures of the activating composition.

If the pH is significantly lower than 2 or higher than 13, almost insufficient activation is obtained. If the pH is too acidic, acid-sensitive reducing agents typically degrade too quickly. Conversely, if the pH is too alkaline, the alkaline-sensitive reducing agent will decompose too quickly.

The aqueous composition utilized in the method (for activation) of the present invention is palladium-free. Accordingly, the activation composition is substantially free or free of palladium ions. This means that neither palladium-containing compounds nor palladium atoms/particles or palladium ions are present. Advantageously, the present invention is a much superior alternative to palladium-containing activation processes with the same or at least nearly the same results in terms of activation.

Preferably, other noble metals or at least expensive/rare metals are also not required in the activation composition. Thus, the activation composition is substantially free or free of platinum, gold, silver, rhodium, ruthenium, and iridium ions, preferably platinum, gold, silver, rhodium, ruthenium, and iridium. Preference is given to methods (for activation) of the invention that are substantially free or free of.

The aqueous composition utilized in the method (for activation) of the present invention comprises (i) dissolved transition metal ions of a first species and additionally metal particles thereof.

Activated compositions in which the metal particles are nanoparticles are preferred. Preferably, the metal particles contain one or more elemental metals (Me ⁰ ), preferably consist (essentially) of one or more elemental metals (Me ⁰ ).

The first type of metal particles are within the range of 0.1 nm to 500 nm, preferably within the range of 0.5 nm to 200 nm, more preferably within the range of 1.0 nm to 100 nm, most preferably within the range of 3 nm to 50 nm, Even more preferred are activated compositions having a particle size within the range of 5 nm to 15 nm, most preferably.

More preferred is the method (for activation) in which the first type of metal particles in the activation composition are colloidal metal particles.

Preference is therefore given to methods (for activation) in which the activation composition is a colloid, preferably a colloidal suspension. However, the activated composition is still a clear but colored solution, mainly due to the coloring effect caused by the dissolved ions of the first species.

In the activated composition, the dissolved transition metal ions of the first species and the metal particles thereof together form the total amount of the first species of metal. In the activated composition, the first species of metal ion and its metal particles are present in an amount of 0.05 g based on the total volume of the activated composition and based on ionic non-particular form. /L to 30.0 g/L, preferably 0.07 g/L to 18.0 g/L, more preferably 0.09 g/L to 12.0 g/L, even more preferably is in the range of 0.11 g/L to 8.0 g/L, most preferably in the range of 0.15 g/L to 6.0 g/L, and even more preferably in the range of 0.2 g/L to 3.0 g/L. Preferred are methods (for activation) of the invention that form a total concentration within a range. This means that in order to determine said total concentration, the transition metal particles of the first species are considered/calculated as dissolved metal ions.

Although the method (for activation) of the invention may in principle be carried out with relatively high concentrations of the first species, it is surprisingly very efficient even at very low concentrations. It was found to be sufficient to obtain excellent results (see example). This is particularly advantageous in terms of wastewater treatment and is therefore low cost and environmentally friendly.

Preference is given to the method (for activation) in which the first species is copper or cobalt, preferably copper. Copper and cobalt are economical metals compared to the commonly used palladium, yet achieve sufficient activation on the surface of non-conductive or carbon fiber-containing substrates. The above-mentioned concentrations most preferably apply to copper and cobalt, most preferably copper.

The source of dissolved copper ions is selected from the group consisting of copper sulfate, copper chloride, copper nitrate, copper fluoroborate, copper acetate, copper citrate, copper phenylsulfonate, copper paratoluenesulfonate, and copper alkylsulfonate. The method (for activation) of the invention is preferred. A preferred copper alkylsulfonate is copper methanesulfonate. The most preferred copper ^source is copper sulfate, most _{preferably CuSO4.5H2O} .

Optionally, the palladium-free aqueous activation composition comprises (iv) one or more second species of dissolved metal ions that are different from the first species. Preferably, the second species is substantially free or free of alkali metals.

The one or more second species are selected from the group consisting of transition metals and magnesium, preferably from the group consisting of nickel, cobalt, iron, and magnesium, preferably from the group consisting of nickel and cobalt, and more Preferred is the method (for activation) of the invention, preferably selected from nickel. By virtue of the second species of dissolved metal ions, a corresponding transition metal alloy is preferably deposited in step (c) of the method (for activation) of the invention.

Preferred are methods of the invention (for activation) in which the one or more second species is substantially free or free of tin.

In addition to the first species and optionally the second species, the palladium-free aqueous activation composition includes (ii) one or more complexing agents. Preferably, the one or more complexing agents are suitable for forming a complex with at least the first species of dissolved transition metal ions.

The one or more complexing agents are organic complexing agents, preferably carboxylic acids and/or salts thereof, more preferably di- or tricarboxylic acids and/or salts thereof, even more preferably tricarboxylic acids and/or salts thereof. Preference is given to methods of the invention (for activation) comprising or comprising salts, most preferably hydroxytricarboxylic acids and/or salts thereof, even more preferably citric acid, structural isomers thereof, and/or salts thereof. . Preferred structural isomers are isocitric acid and its salts. Most preferably, one or more complexing agents as defined above (including preferred variations) are the only complexing agents in the activation composition.

In the activation composition,
- a first species of metal ions and metal particles thereof, which together constitute a total concentration based on the total volume of the activating composition and on the basis of the ionic non-specific form;
- one or more complexing agents as a total concentration,
Within the range of 1.0:0.2 to 1.0:100.0, preferably within the range of 1.0:0.5 to 1.0:50.0, more preferably 1.0:0.85 1.0:25.0, even more preferably 1.0:0.95 to 1.0:15.0, even more preferably 1.0:1.0 to 1.0:25.0. Preference is given to the method (for activation) of the present invention in which they are present in a molar ratio within the range 0:10.0, most preferably within the range 1.0:1.1 to 1.0:5.0. This means that one or more complexing agents bind tricarboxylic acids and/or salts thereof, more preferably hydroxytricarboxylic acids and/or salts thereof, most preferably citric acid, structural isomers thereof, and/or This applies very preferably when the salt thereof is included.

The one or more complexing agents in the activation composition may be present in an amount ranging from 0.01 mol/L to 0.5 mol/L, preferably 0.015 mol/L, based on the total volume of the activation composition. Present in a total amount within the range of L to 0.35 mol/L, more preferably within the range of 0.02 mol/L to 0.3 mol/L, most preferably within the range of 0.023 mol/L to 0.275 mol/L. The method (for activation) of the invention is preferred.

In addition to the first species, optionally the second species, and the one or more complexing agents, the palladium-free aqueous activation composition permanently or temporarily comprises (iii) 1 or more than one reducing agent. One or more reducing agents are essential for forming metal particles from at least the first species of dissolved transition metal ions. To that end, dissolved transition metal ions are continuously or semi-continuously chemically reduced to form said particles. Thus, the particles are formed either continuously or semi-continuously, depending on the presence of one or more reducing agents in the activation composition, which is permanent or temporary, respectively. . However, if one or more reducing agents are present, typically the particles will form until the reducing agents are used up or insufficiently present. Preference is given to the method of the invention (for activation) in which oxidation affects the particles and is always in competition with reduction. Typically, oxidation begins as soon as the reducing agent or agents are used up, which is explicitly desired in the context of the present invention.

Said oxidation may further be carried out in the method (for activation) of the invention if the method is interrupted for a relatively long period of time after one or more of the first steps (c). Very reasonable. To prevent the precipitation of aggregates during such a period of time, the oxidation is carried out until there are no more particles and only dissolved transition metal ions in the activated composition. be exposed. Preferably, oxidation is facilitated by adding an oxidizing agent, more preferably a peroxide, most preferably hydrogen peroxide. Upon resumption of operation, the particles are formed by continuous or semi-continuous addition of one or more reducing agents to reform the particles. Thereafter, the method (for activation) of the invention is restarted.

Therefore, preferably the one or more reducing agents are suitable for reducing at least the first species of dissolved transition metal ions.

Optionally, the one or more reducing agents contain one or more hydrogen atoms, such that hydrogen is released upon reduction of the transition metal ion and at least partially adsorbs on the activated surface. Preferred are methods of the invention (for activation) involving atoms.

Preference is given to the process of the invention (for activation) in which the one or more reducing agents comprise boron-containing reducing agents, preferably borohydrides. Preferred borohydrides include inorganic borohydrides and/or organic borohydrides. Preferred organic borohydrides include alkylaminoborane, most preferably dimethylaminoborane. Preferred inorganic borohydrides include alkali borohydrides, most preferably sodium borohydride. In the method (for activation) of the invention, most preferred are alkali borohydrides, preferably sodium borohydride. This allows a slightly acidic pH and a temperature in a mild range, preferably from 15° C. to 30° C., in step (c) of the method (for activation) of the invention. These are very good room temperature conditions. Therefore, additional costly heating is not necessarily required. Additionally, hydrogen is produced.

Preferably, the boron-containing reducing agent, preferably a borohydride, more preferably an alkali borohydride and/or an alkylaminoborane, most preferably sodium borohydride and/or dimethylaminoborane, is the only one in the activation composition. It is a reducing agent.

Boric acid and/or its salts are typically formed as a result of utilizing a borohydride as one of the one or more reducing agents in the activation composition.

Optionally, the one or more reducing agents of the invention (activated ) method is preferred. In such cases, the formation of boric acid is avoided.

In some cases, the method (for activation) of the invention is preferred in which the one or more reducing agents comprise hydrazine, most preferably as the only reducing agent. In such cases, the formation of boric acid is again avoided.

The activation composition is within the range of 0.2 mmol/L to 500.0 mmol/L, preferably within the range of 0.4 mmol/L to 350.0 mmol/L, based on the total volume of the activation composition, and more. Preferably within the range of 0.6 mmol/L to 250.0 mmol/L, even more preferably within the range of 0.8 mmol/L to 150.0 mmol/L, most preferably 1.0 mmol/L to 80.0 mmol/L. Preference is given to methods (for activation) of the invention comprising one or more reducing agents at a total concentration within the range of . Particularly preferred total concentrations are in the range 0.9 mmol/L to 50.0 mmol/L, very preferably in the range 1.0 mmol/L to 30.0 mmol/L, most preferably in the range 1.1 mmol/L to 10 It is within the range of .0 mmol/L. Most preferably, this applies to the preferred, more preferred, etc. reducing agents mentioned above, most preferably to borohydrides.

In the activation composition,
- a first species of metal ions and metal particles thereof that together form a total concentration based on the total volume of the activating composition and on the basis of the ionic non-specific form;
- one or more reducing agents as a total concentration (if added semi-continuously, at the moment of addition);
It is generally preferred that the method (for activation) is present in a molar ratio greater than 0.5, preferably greater than 1, more preferably greater than 2, even more preferably greater than 3, most preferably greater than 3.5. . Molar ratios within the range 1 to 20 are highly preferred. Thus, in the activating composition, the one or more reducing agents are present in a total concentration such that the dissolved transition metal ions of the first species are not quantitatively reduced to the corresponding particles (permanently). or temporarily) is preferred. Furthermore, methods of the invention (for activation) are preferred in which the activation composition does not present a predominantly reducing environment that prevents oxidation of the metal particles. On the contrary, as already mentioned, oxidation is necessary and desired. Preference is therefore given to methods (for activation) in which the activation composition is maintained predominantly at oxidizing conditions that allow oxidation of the metal particles.

In the activating composition
- a first species of metal ion and metal particles, which together form a total concentration based on the total volume of the activating composition and based on the non-specific form of ionicity;
the reducing agent or agents as a total concentration (at the moment of addition, if added semi-continuously),
Particularly preferred is the method of the present invention (for activation) where the molar ratio is in the range of 0.3 to 60.0, preferably in the range of 0.5 to 30.0, more preferably in the range of 1.0 to 20.0, even more preferably in the range of 1.5 to 10.0, and most preferably in the range of 1.8 to 3.0.

In some cases, methods of the invention (for activation) in which the reducing agent or agents are permanently present in the palladium-free aqueous activation composition are preferred. Accordingly, the one or more reducing agents are added to the activation composition continuously, preferably by a constant flow of the respective liquid containing said one or more reducing agents. is preferred. In this approach, oxidation and reduction occur simultaneously over the time that step (c) of the method (for activation) of the invention is carried out. As a result, metal particles are present in a relatively constant concentration.

Alternatively, methods of the invention (for activation) are preferred in which the reducing agent or agents are temporarily present in the palladium-free aqueous activation composition. Preferably, therefore, the reducing agent or agents are added semi-continuously, eg in successive doses with a time break between each dose. This means that new particles are formed when one or more reducing agents are added. However, during interruptions, oxidation is very predominant, producing dissolved transition metal ions. As a result, metal particles are present in essentially varying concentrations. However, depending on the length of the interruption in time and ensuring that the interruption is not too long, such an approach can be Fully sufficient to activate the surface well. This approach is therefore particularly preferred.

However, in any case, preference is given to the process according to the invention (for activation) in which one or more reducing agents are present in such a way that the equilibrium is maintained reversibly. Therefore, a reversible equilibrium is not just a side reaction or an undesired side reaction.

During oxidation, the total concentration of dissolved transition metal ions in the activated composition essentially increases as a result of a reversible equilibrium, and the total amount of said metal particles decreases. This reversible equilibrium is preferably monitored for better process control. Preference is therefore given to the method of the invention (for activation) in which the reversible equilibrium is monitored by UV/VIS inspection. Preferably, said dissolved transition metal ions are monitored at a wavelength within the range of 700 nm to 800 nm, within the range of 710 nm to 780 nm, more preferably within the range of 720 nm to 760 nm, most preferably within the range of 730 nm to 750 nm. It is also preferred that the metal particles are monitored at a wavelength within the range of 400 nm to 600 nm, preferably within the range of 450 nm to 550 nm. This makes it possible to determine when to add one of the one or more reducing agents for the purpose of forming, preferably reforming, the metal particles in order to increase their total amount.

Accordingly, the one or more reducing agents are activated continuously or semi-continuously such that further metal particles are formed continuously or semi-continuously from the dissolved transition metal ions of the first species, respectively. Preference is given to methods of the invention (for activation) in which the active ingredient is added to the activated composition, preferably after one or more step (c) has been carried out.

The first type of metal particles are continuously or in situ in the activated composition by said reduction after and/or while one or more step (c) is carried out. Preference is given to the method (for activation) of the invention which is formed semi-continuously. This preferably defines that in the method (for activation) of the invention step (c) is carried out more than once, preferably that the method comprising step (c) is carried out repeatedly. After one step (c), two or more steps (c), or each step (c) of the method (for activation) of the invention, metal particles are newly formed by said reduction. It is very preferable. This is possible because said oxidation is possible and desired, thereby leading to new dissolved transition metal ions which are immediately re-reduced, preferably continuously but at least semi-continuously. This means that the metal particles are formed (and stabilized) before activation takes place, and the metal particles are then typically used until the corresponding activation composition becomes destabilized and unusable. This is in contrast to the common practice of stabilization to survive as long as possible.

As mentioned throughout the text, in the context of the present invention it is preferably necessary to add the reducing agent at least semi-continuously. Typically, the reducing agent used for said reduction reacts with dissolved transition metal ions, resulting in reducing agent decomposition products, preferably boric acid and/or its salts. Normally such degradation products accumulate in the activation composition, which is not preferred in the context of the present invention. Preference is therefore given to the method (for activation) of the invention in which the method is carried out by bleed and feed. In such techniques, a certain volume of the activation composition is removed (e.g., by withdrawal; decomposition products are also removed) such that the essential components in the activation composition have a sufficiently constant concentration. ), replaced by a displacement volume (e.g. by replenishment). This means that the displacement volume is typically free of boric acid and/or its salts, preferably free of decomposition products of the reducing agent. This is also beneficial for stabilizing the pH to an essentially constant pH.

The activation composition has a total concentration of no more than 5 g/L, preferably no more than 3 g/L, more preferably no more than 2 g/L, most preferably no more than 1.2 g/L, based on the total volume of the activation composition. Preference is given to methods according to the invention (for activation) involving acids and/or their salts. This is preferably the case under the conditions that (1) the one or more reducing agents comprise a borohydride, and (2) step (c) is carried out more than once.

Preference is given to methods (for activation) according to the invention in which the reversible equilibrium is not shifted predominantly towards the metal particles over the majority of the time that step (c) is carried out.

Preference is given to the method (for activation) according to the invention, in which during and/or after step (c) a large portion of said metal particles undergo said oxidation. By majority it is preferably meant more than 50% of the particles.

Preferably, the one or more reducing agents are substantially free or free of hypophosphite ions, and preferably substantially free or free of phosphorus-containing reducing agents. The inventor's own experiments have shown that in some cases activation by such reducing agents is too weak or even incomplete.

As already outlined above, the activated composition does not require additional stabilizing compounds. Accordingly, the activation composition is substantially free or free of compounds that prevent oxidation of the metal particles and/or substantially free or free of stabilizer compounds for stabilizing the metal particles. The inventive method (for activation) is preferred. Preferably, the activated composition is substantially free or free of stabilizer compounds to stabilize the metal particles by preventing agglomeration of the metal particles. In the context of the present invention, one or more reducing agents (temporarily or permanently present in the activated composition) and compounds involved in the oxidation, preferably ambient air and/or oxygen gas (i.e. , most preferably molecular oxygen) are not considered to be such compounds. Rather, one or more reducing agents are necessary for the formation of metal particles, including reformation of the particles. This means that the activation composition does not substantially contain a stabilizer compound and/or a compound that prevents oxidation of the metal particles other than the one or more reducing agents and the compounds involved in oxidation. means not included. Therefore, the one or more reducing agents are not present in a total amount that prevents oxidation, preferably after or while one or more step (c) is carried out. It is preferred that the method of the invention (for activation) is not present in total amounts. As outlined, oxidation, most preferably by ambient air, is necessary to reform the dissolved transition metal ions and prevent the formation of agglomerates of the metal particles that precipitate.

The activation composition of the present invention is substantially free or free of compounds that completely or partially encapsulate the metal particles or completely or partially adsorb onto the surface of the particles. ) method is preferred. Some stabilizer compounds are believed to be based on such functionality. In the context of the present invention, this is not desired.

Generally, the activating composition is substantially free or free of compounds that prevent the equilibrium from becoming reversible and/or substantially free of compounds that shift the equilibrium completely toward the metal particles. Preference is given to the method (for activation) of the invention without or without. Again, for the reasons outlined above, the reducing agent or agents are not considered to be such compounds.

The activation composition is substantially free or free of tin ions, preferably substantially free or free of tin ions, lead ions, germanium ions, gallium ions, antimony ions, bismuth ions, and aluminum ions. Preference is given to processes according to the invention which are substantially free or free of metal ions, preferably of main group elements of groups III, IV and V of the Periodic Table of the Elements. In the context of the present invention, "metal ions of main group elements of group III" do not include corresponding boron-containing ions. In particular, tin ions are very well known to prevent the oxidation of, for example, copper particles in corresponding palladium-free copper-tin activated compositions, thereby preventing the equilibrium from becoming reversible. be done. Such tin ions typically form a reducing environment, which is completely undesired in the context of the present invention.

The activation composition is substantially free or free of polyvinylpyrrolidone, preferably substantially free or free of polyvinyl compounds, more preferably substantially free or free of organic polymers containing vinyl moieties. , most preferably substantially free or free of dissolved organic polymers.

Preferred are methods (for activation) in which the activation composition is substantially free or free of proteins, agar, gum arabic, sugars, and polyhydric alcohols.

Preferred are methods of the invention (for activation) in which the activation composition is substantially free or free of glycerol.

Preferred are methods (for activation) in which the activation composition is substantially free or free of gelatin.

The activation composition is substantially free or free of thiourea, preferably substantially free or free of sulfur-containing compounds including divalent sulfur, and more preferably contains sulfur with an oxidation number of +5 or less. Preference is given to methods (for activation) of the invention that are substantially free or free of sulfur-containing compounds.

The present invention wherein the activation composition is substantially free or free of compounds containing aromatic rings and sulfonic acid groups (including salts thereof), preferably substantially free or free of sulfonic acids or salts thereof. The method (for activation) is preferred.

Preference is given to the method of the invention (for activation) in which the activation composition is substantially free or free of the compound with the name Orzan-S.

Preference is given to methods (for activation) in which the activation composition is substantially free or free of urea.

Preferred are methods of the invention (for activation) in which the activation composition is substantially free or free of dispersants.

The activated composition is substantially free or free of polyethyleneimine, preferably substantially free or free of polyalkyleneimine, most preferably substantially free or free of organic polymers containing imine moieties. Preference is given to the method (for activation) of the invention in which there is no activation.

In particular, the polymers mentioned above are commonly used as stabilizer compounds to stabilize metal particles. However, in the context of the present invention, polymers are not required. Furthermore, metal particles are believed to be significantly more effective/active when such molecules do not form a shell around the particles.

The activation composition is substantially free or free of sodium dodecyl sulfate, preferably substantially free or free of alkyl sulfates having 8 to 20 carbon atoms, more preferably alkyl sulfates. Preferred are methods (for activation) of the invention that are substantially free or free, most preferably substantially free or free of surfactants.

Preference is given to the method (for activation) in which the activation composition is substantially free or free of hydroquinone, pyrogallol and/or resorcinol, preferably substantially free or free of hydroxybenzene. . In many cases, such hydroxybenzenes are commonly used as antioxidants, which prevent the equilibrium from becoming reversible, and which are not needed in activated compositions.

Preferred are methods (for activation) in which the activation composition is substantially free or free of quinones.

Preference is given to methods (for activation) in which the activation composition is substantially free or free of fatty alcohols.

Preference is given to methods (for activation) in which the activation composition is substantially free or free of alkylene glycols, preferably substantially free or free of glycols.

Preference is given to methods (for activation) in which the activation composition is substantially free or free of manganese ions.

Preference is given to methods (for activation) in which the activation composition is substantially free or free of zinc ions.

Particularly as a result of the fact that the activation composition does not contain stabilizing compounds and/or compounds that prevent the oxidation of the metal particles, the activation composition does not contain precipitating agglomerates of said metal particles. Preference is given to methods (for activation) of the invention that are substantially free or free of. This is achieved because the oxidation is not inhibited (i.e. avoided), but rather the dissolved transition metal ions of at least the first species and its metal particles contribute to said reduction and said oxidation, respectively. This is because they are repeatedly involved.

"Repeatedly engaging" expressly refers to at least two or more times, preferably three or more times, even more preferably four or more times, most preferably five or more times, and even most preferably over the entire life of the activating composition. Preferred is the method (for activation) of the invention comprising:

The inventor's own experiments have shown that it is specifically oxidation that prevents agglomeration. The metal particles return to their ionic/dissolved form through oxidation. This means that the particles do not have enough time to form higher order aggregates or even aggregates. Although each of the suitable oxidizing agents is basically applicable, ambient air has been shown to be a very good choice. It is strong enough and available everywhere. Preference is given to the method of the invention (for activation) in which the formation of precipitated agglomerates of the metal particles is prevented by the oxidation, preferably by oxidation with ambient air and/or oxygen gas. Preference is given to the method of the invention (for activation) in which dissolved transition metal ions are formed from metal particles by oxidation with ambient air and/or oxygen gas. In either case, the preferred oxidizing agent is molecular oxygen. Most preferred are methods of the invention (for activation) in which the majority of the dissolved transition metal ions are formed from the majority of metal particles by oxidation by ambient air and/or oxygen gas.

In some cases, continuous or semi-continuous oxidation is achieved in accordance with the invention, additionally or solely, by an oxidizing agent that is not molecular oxygen, more preferably by a peroxide, most preferably by hydrogen peroxide. The method (for activation) is preferred. In particular, in addition to the ambient air, this preferably promotes the oxidation of the particles where this is required, for example when the activated composition needs to be stored inert for a long period of time. .

In order to sufficiently promote oxidation in the activated composition, the activated composition of the present invention is circulated continuously or semi-continuously, preferably by shaking, stirring, and/or pumping. ) is preferred. This is preferred to ensure that the oxidation is evenly distributed throughout the activation composition. In other words, this ensures that the metal particles are evenly contacted with the oxidizing agent and oxidation is promoted.

Very most preferred is a method for (activating) the surface of a non-conductive or carbon fiber-containing substrate for metallization, comprising:
(a) preparing the base material;
(b)
(i) a first type of dissolved transition metal ion that is copper and additionally colloidal metal particles thereof;
(ii) one or more complexing agents comprising hydroxytricarboxylic acids and/or salts thereof, preferably citric acid, structural isomers thereof, and/or salts thereof;
(iii) permanently or temporarily one or more boron-containing reducing agents, preferably borohydrides;
(iv) optionally providing a palladium-free aqueous composition comprising one or more dissolved metal ions of a second species, different from the first species, preferably nickel;
- the activation composition is a colloidal suspension, and - at least a first species of dissolved transition metal ions and metal particles thereof are present in reversible equilibrium, with the proviso that:
- the metal particles are formed from dissolved transition metal ions by continuous or semi-continuous reduction with one or more reducing agents,
- dissolved transition metal ions are formed from the metal particles by oxidation by ambient air, by continuous or semi-continuous oxidation of said particles, and - dissolved transition metal ions and their metal particles are formed, respectively, by precipitation of said metal particles. repeatedly participating in the reduction and the oxidation so that no aggregates are formed;
and (c) contacting the substrate with the activating composition such that a transition metal or transition metal alloy is deposited on the surface of the substrate to provide an activated surface for metallization. and the metal particles are continuously or semi-continuously in situ in the activated composition by said reduction after and/or while one or more step (c) is carried out. The process of forming
A method including:

The present invention also provides palladium-free aqueous activation compositions (preferably of the present invention) for activating the surface of non-conductive or carbon fiber-containing substrates for metallization. ) A method for producing an activated composition () for use in a method, comprising:
(1)
- a dissolved transition metal ion of the first species,
- providing a starting aqueous solution comprising - one or more complexing agents and - optionally one or more dissolved metal ions of a second species different from the first species,
(2) one or more reducing agents are continuously added to the starting solution such that metal particles of at least the first type of dissolved transition metal ions are formed continuously or semi-continuously in the solution; or semi-continuously adding, wherein the metal particles are continuously or semi-continuously oxidized to form a first species of dissolved transition metal ions.
Regarding the method.

Preferably, what has been described above with respect to the method (for activation) of the present invention also applies to the method of the present invention for producing palladium-free aqueous activation compositions, and most preferably what has been described above as preferred. As defined, it applies.

The present invention also provides continuous or semi-continuous production of a first species of dissolved transition metal ions to continuously or semi-continuously form metal particles in situ in a palladium-free aqueous activated composition. It also relates to the use of a combination of reduction and continuous or semi-continuous oxidation of the first type of metal particles in reversible equilibrium.

Preferably, what has been said above regarding the method (for activation) of the invention applies analogously to the use of the invention, most preferably as defined above as preferred.

The invention also provides a palladium-free aqueous activation composition for activating the surface of a non-conductive or carbon fiber-containing substrate for metallization, comprising:
(i) a first species of dissolved transition metal ions and additionally metal particles thereof;
(ii) one or more complexing agents;
(iii) one or more reducing agents, permanently or temporarily;
(iv) optionally comprising one or more dissolved metal ions of a second species different from the first species;
- at least a first species of dissolved transition metal ions and metal particles thereof exist in reversible equilibrium, with the proviso that
- the metal particles are formed from dissolved transition metal ions by continuous or semi-continuous reduction with one or more reducing agents,
- dissolved transition metal ions are formed from the metal particles by continuous or semi-continuous oxidation of said particles, and - dissolved transition metal ions and their metal particles, respectively, do not form precipitating agglomerates of said metal particles. repeatedly participating in said reduction and said oxidation,
Regarding the composition.

Preferably, what has been said above regarding the method (for activation) of the invention applies likewise to the palladium-free aqueous activation compositions of the invention, most preferably as defined above as preferred. .

The activation composition of the present invention can be activated at a temperature within the range of 10°C to 90°C, preferably within the range of 14°C to 75°C, more preferably within the range of 16°C to 65°C, most preferably within the range of 18°C to 45°C. obtained at and/or having a temperature within a range, more preferably within a range of 20°C to 32°C. In particular, the temperature is preferably in the range of 18°C to 45°C, preferably in the range of 20°C to 32°C, provided that the one or more reducing agents are borohydrides, preferably sodium borohydride. It is. This particularly preferably applies also to the method according to the invention (for producing said activation composition) and the method according to the invention (for activation).

More preferably, the activated compositions of the invention are not obtainable and/or do not have temperatures above 110°C, preferably above 100°C, more preferably above 95°C. Most preferably, the activated composition of the present invention is not obtained at temperatures above 110°C. This preferably applies equally to the method of the invention (for producing said activation composition) and the method of the invention (for activation).

activation:
In step (c) of the method (for activation) of the invention, the substrate is prepared for metallization by depositing a metal or metal alloy, i.e. by depositing a seed layer or an activation layer. To obtain an activated surface, it is contacted with a palladium-free aqueous activation composition.

In step (c), the contacting is carried out at a temperature in the range of 10°C to 90°C, preferably in the range of 14°C to 75°C, more preferably in the range of 16°C to 65°C, most preferably in the range of 18°C to 45°C. Preference is given to the process (for activation) carried out at a temperature within the range, more preferably within the range 20°C to 32°C. Particularly preferred temperature in step (c) is in the range of 18°C to 45°C, preferably in the range of 20°C to 32°C, and the reduction with one or more reducing agents is performed by reducing the borohydride, Preferred is sodium borohydride.

In step (c), the contacting is carried out for a period of time ranging from 1 minute to 10 minutes, preferably from 2 minutes to 8 minutes, more preferably from 3 minutes to 6 minutes, most preferably from 3.5 minutes to 5 minutes. The method (for activation) of the invention is preferred.

Preference is given to a process according to the invention (for activation) in which step (c) is followed by a rinsing step. In such cases, a rinsed activated surface for metallization is obtained. Preferably, rinsing is done with water.

Even more preferably, the method is performed for at least 10 days, preferably for at least 50 days, more preferably for at least 200 days, without replacing a majority of the activating composition (i.e., more than 50% by volume of the composition) in one step. Preferably, the method (for activation) of the invention is carried out over a period of one year or more, most preferably two years or more, even more preferably five years or more.

Metallization:
The invention further provides a method of metallizing the activated surface of a non-conductive or carbon fiber-containing substrate, comprising:
(A) A non-conductive substrate with an activated surface for metallization, obtained by the method (for activation) of the invention, preferably as defined as preferred throughout this document. or a step of preparing a carbon fiber-containing base material;
(B) metallizing the activated surface by contacting the activated surface with a first metallization solution such that a first metallization layer is deposited on the activated surface;
Regarding the method.

In step (A) of the method (for metallization) of the invention, a non-conductive substrate or a carbon fiber-containing substrate with an activated surface is obtained by the method (for activation) of the invention. Please refer to the text above for details. Preferably, what has been said above regarding the method (for activation) of the invention applies to the method for metallization of the invention, most preferably as described as preferred.

In step (B), the first metallization layer is a further layer deposited on the transition metal or transition metal alloy obtained in step (c) of the method (for activation) of the invention. The method (for metallization) of the invention is preferred.

In step (B), the first metallization solution is essentially free or free of reversible equilibrium between metal ions and particles thereof, more preferably essentially free of metal/metal alloy particles. Preferably, the method (for metallization) of the present invention is essentially free or free, most preferably essentially free or free of any particles.

Preference is given to the process (for metallization) according to the invention, in which, in step (B), the first metallization solution comprises or does not contain a reducing agent.

Step (B) is within the range of 10°C to 95°C, preferably within the range of 15°C to 85°C, more preferably within the range of 20°C to 65°C, even more preferably within the range of 25°C to 55°C. Preferably, the process (for metallization) of the invention is carried out at a temperature in the range of 30°C to 45°C, most preferably 30°C to 45°C.

(for metallization) in which step (B) is carried out for 30 seconds to 180 minutes, preferably 45 seconds to 120 minutes, more preferably 1 minute to 60 minutes, most preferably 1.5 minutes to 45 minutes. ) method is preferred.

In step (B), the first metallization solution does not contain a reducing agent and is an immersion type metallization solution, preferably from the group consisting of palladium ions, platinum ions, silver ions, gold ions, and mercury ions. The present invention comprises one or more selected species ions, more preferably palladium ions, and most preferably palladium ions at a total concentration within the range of 0.05 mg/L to 20 mg/L. The method (for metallization) is preferred.

More preferred is the method (for metallization) of the invention, wherein in step (B), the first metallization solution is an acidic palladium dip metallization solution.

In step (B), the first metallization solution contains palladium ions in a range of 0.09 mg/L to 10.0 mg/L, preferably 0.1 mg/L, based on the total volume of the metallization solution. 5.0 mg/L, more preferably 0.12 mg/L to 3.0 mg/L, even more preferably 0.15 mg/L to 2.0 mg/L, most preferably The present invention is an immersion metallization solution comprising (metal ) is preferred. This is especially true if the metallization solution is acidic. In combination with the method (for activation) of the invention, such a metallization solution surprisingly requires a significantly lower concentration of palladium ions compared to conventional prior art metallization solutions. Although low, in the context of the present invention it does not compromise the metallization results/quality.

Alternatively, in step (B), the first metallization solution contains a reducing agent, preferably contains one or more species of transition metal ions, more preferably contains copper ions and/or nickel ions. Preference is given to the method (for metallization) of the invention which is an autocatalytic metallization solution.

However, the first metallization solution, regardless of its type, is preferably a clear, particle-free solution.

Preference is given to the method (for metallization) of the invention, comprising:
(A) A non-conductive substrate with an activated surface for metallization, obtained by the method (for activation) of the invention, preferably as defined as preferred throughout this document. or a step of preparing a carbon fiber-containing base material;
(B) treating the activated surface with a first metallization solution, which is an autocatalytic metallization solution comprising copper ions and a reducing agent, and a first metallization layer comprising copper or a copper alloy deposited on the activated surface; metallizing the activated surface by contacting it so as to
A method including:

Alternatively, preferred is the method (for metallization) of the invention, comprising:
(A) A non-conductive substrate with an activated surface for metallization, obtained by the method (for activation) of the invention, preferably as defined as preferred throughout this document. or a step of preparing a carbon fiber-containing base material;
(B) activating the activated surface with a first metallization solution that is an immersion metallization solution (preferably as described above) comprising palladium ions and a first metallization layer comprising palladium; (C) metallizing the activated surface by contacting the activated surface such that the second metallization layer is at least partially deposited on the first metallization layer; 1. A method comprising metallizing a first metallization layer by contacting a second metallization solution such that the first metallization layer is deposited on the metallization layer.

Preference is given to the method (for metallization) according to the invention, in which in step (C) the second metallization solution comprises a reducing agent, preferably a reducing agent and nickel ions.

Preference is therefore given to the method (for metallization) according to the invention, in which in step (C) the second metallization layer comprises nickel, preferably a nickel layer or a nickel alloy layer.

However, in other cases the method (for metallization) of the invention is preferred, in which in step (C) the second metallization solution comprises a reducing agent, preferably a reducing agent and copper ions.

Preference is therefore given to the method (for metallization) according to the invention, in which in step (C) the second metallization layer comprises copper, preferably a copper layer or a copper alloy layer.

In other cases, the method (for metallization) of the invention is preferred, in which in step (C) the second metallization solution comprises a reducing agent, preferably a reducing agent and cobalt ions.

Preference is therefore given to the method (for metallization) according to the invention, in which in step (C) the second metallization layer comprises cobalt, preferably a cobalt layer or a cobalt alloy layer.

In step (C), the deposition of the second metallization layer starts within 8 seconds to 30 seconds, preferably within 10 seconds to 25 seconds, most preferably within 12 seconds to 20 seconds. ) method is preferred. This is most preferably the case if the second metallization layer comprises nickel, preferably a nickel layer or a nickel alloy layer. The inventor's own experiments have therefore shown that the first metallization layer containing palladium acts as a booster for the second metallization layer of nickel or nickel alloy.

The invention will be described in more detail by the following non-limiting examples.

Substrate provision:
Throughout all experiments, the substrate is either FR4 (Substrate 1, resin-containing laminate, 5×5 cm test plate) or ABS (Substrate 2, plastic, 3 cm diameter test plate).

Preprocessing:
Unless otherwise stated, at least each substrate is treated with a pretreatment solution containing a nitrogen-containing compound, in particular polyquaternium 6, for 4 minutes at a temperature of approximately 50°C. The pretreated substrate is then rinsed with water.

Activation composition and activation:
Contacting the substrate with an activation composition (hereinafter abbreviated as AC for compositions according to the invention and hereinafter abbreviated as cAC for comparative activation compositions) provides an activated surface for subsequent metallization. Do this for a sufficient period of time (contact time).

The activation composition according to the invention contains citric acid as complexing agent. The first species is copper. The total starting volume of each activated composition is approximately 0.5L.

Certain individual parameters of the corresponding activation compositions as well as the results are summarized in the table below. Each activated composition according to the invention is free (i.e., completely free) of palladium, compounds that intentionally prevent oxidation of the copper particles, and stabilizer compounds to stabilize the copper particles and prevent agglomeration. (not). In fact, the activated composition essentially consists of the components mentioned together herein and their reaction products.

Example of the first set:

Regarding the first set of examples, the first step provides a starting aqueous solution containing dissolved copper ions, citric acid, and optionally dissolved nickel ions. This solution is clear and has a typical blue/bluish color.

When an initial amount of NaBH ₄ (see Table 1) is added under moderate stirring, the boron-containing reducing agent is temporarily present and some of the dissolved copper ions are immediately reduced. , copper nanoparticles are formed. Typically, not all copper ions are reduced in this initial reduction. During the reduction, hydrogen gas is produced. Reduction is basically complete when gas production stops. Once particles are formed (particle size approximately 10 nm), the starting solution becomes a colloidal activated composition. The color is dark brown and no precipitated aggregates are observed. The composition continues to be agitated and continues to be in contact with the surrounding air. Therefore, oxidation of the particles formed is not prevented at all, especially after the reduction has ended. The corresponding activation composition is further stirred so that the copper particles are still undergoing oxidation and are ready for the first activation.

Subsequently, step (c) of the method (for activation) of the invention is carried out for the first time. For each substrate, copper and copper alloys, each well-adhered and non-rinsable, are deposited on the surface of the corresponding substrate. The activation is in each case very good and sufficient for the subsequent metallization.

Thereafter, AC#1 to AC#3 are stored for 2 days with stirring (initial +2). The onset of discoloration is seen, ie from dark brown to light brown with increasing bluish color. It shows that due to reversible equilibrium, the total amount of copper particles decreases and the total concentration of dissolved copper ions increases. However, activation was successfully repeated with AC#1-AC#3 and a second set of substrates (FR4 and ABS) with very similar backlight results (regarding backlight testing). See below for further information).

After activation of the second set of substrates, ie after the initial +2, 5 ml of NaBH ₄ solution (c=2 g/L) is added to each of AC#1 to AC#3. Prior to the addition of _NaBH4 , a small amount is separated from samples AC#1 and AC#2 as reference (cAC#1 and cAC#2). cAC #1 and cAC #2 have no NaBH ₄ added and no agitation to substantially prevent continuous or semi-continuous oxidation therein. After adding the above amount of NaBH ₄ to AC#1-AC#3, the third set of substrates (FR4 and ABS) are successfully activated with very similar backlight results.

After 3 days (initial +3), the fourth set of substrates (FR4 and ABS) are activated well, again with very similar backlight results. Subsequently, 2.5 ml of NaBH ₄ solution (c=2 g/L) was added to each composition AC#1 to AC#3, and the fifth set of substrates (FR4 and ABS) were also very Activates well with similar backlight results. This procedure is repeated after 4 days (initial+4) with the corresponding sixth and seventh sets of substrates.

After 9 days (initial +9), 10 ml of NaBH ₄ solution (c=2 g/L) was added to each composition AC#1-AC#3, and the 8th set of substrates (FR4 and ABS) were still good. is activated.

After addition of _NaBH4 , the pH finally increased slightly up to 6 without manual readjustment.

Regarding the reference sample, cAC #1 showed a bluish/greenish color and precipitating aggregates after 5 days (initial +5). cAC#2 turned blue after an initial +5 and was a particle-free solution. In principle, such an activated composition can be stored and resumed for use after addition of additional reducing agent. However, in this condition it is not possible to obtain activation with it.

As a final result, AC#1-AC#3 do not additionally require any antioxidant compounds and/or specific stabilizer compounds to prevent agglomeration. In contrast, activated compositions are maintained active over time by maintaining a reversible equilibrium, particularly and even by maintaining a predominantly oxidizing environment.

A test with AC#3 containing 5.2 mmol/L of sodium borohydride instead of 2.6 mmol/L gives very good results as well.

Backlight test (state of metal coating on base material surface):
The coating condition is evaluated using the industry standard backlight test, which separates the corresponding substrate and allows areas of incomplete coating to be detected as bright spots when viewed with a strong light source. (Compare US Patent Application Publication No. 2008/0038450 (A1) and WO 2013/050332). The quality of the coating is judged by the amount of light observed under a conventional optical microscope. The results are given on a scale from D1 to D10, where D1 (less incomplete coverage) means the worst result and D10 (complete and strong coverage) the best result.

Example of second set:
A second set of examples tests for activation and subsequent metallization. The specific individual parameters used for this purpose are summarized in Table 2. The general parameters outlined above for the first set of examples apply equally.

Regarding the second set of examples, contacting according to step (c) of the method (for activation) of the invention is carried out after preparation of the activation composition.

Subsequently, in a first approach, the method (for metallization) of the invention is carried out with a first metallization solution in order to obtain a first metallization layer. The first metallization solution is an electroless autocatalytic copper bath containing copper ions (approximately 2 g/L Cu ²⁺ ) and an aldehyde as a reducing agent, and the metallization parameters are as follows: pH 11; 35°C, 20 minutes. After activation, a well-adhering first metallization layer of copper is obtained covering the entire activated surface (no plating defects are observed).

In each of AC#4-AC#7, reversible equilibrium is maintained by intentionally not preventing oxidation by ambient air. Additionally, NaBH ₄ solution is added semi-continuously to reform the particles if necessary. No precipitated aggregates are observed.

In the second approach, FR4 samples activated with AC#5 to AC#7, respectively, were treated with the present invention using a first metallization solution containing nickel instead of copper to deposit a nickel-phosphorus layer. (for metallization), the metallization parameters are as follows: 85° C. for more than 5 minutes, pH approximately 5.0. After activation, a nickel-phosphorus layer can be deposited directly as the first metallization layer.

Typically, after preparation of the activation composition, for example in the case of AC#4, the total concentration of boric acid present is less than 0.2 g/L. To investigate the effect of boric acid, AC#4 was further utilized to intentionally add boric acid to a total concentration of 1 g/L (AC#4-1) and 10 g/L (AC#4-10). Make an additional modification of adding acid. In both cases the pH increases to approximately 5.5. However, no differences regarding activation and metallization are observed.

Example of third set:
In the third set of examples, AC#4 is again used as dimethylaminoborane (DMAB) instead of _NaBH4 . As a result, AC#8 is obtained. Further specific individual parameters are summarized in Table 3.

Activation with AC#8 is performed with and without pretreatment and is equally good. However, compared to the example with sodium borohydride, higher temperatures are required to obtain adequate activation.

In the case of AC#8, reversible equilibrium is also maintained by not intentionally preventing oxidation by ambient air. Additionally, DMAB solution is added semi-continuously to reform the particles as needed. No precipitated aggregates are observed.

Example of the fourth set:
A fourth set of examples further varies the parameters as summarized in Table 4.

In AC#9 to AC#13, reversible equilibrium is also maintained by not intentionally preventing oxidation by ambient air, and reducing agent is added semi-continuously to reform the particles as needed. . No precipitated aggregates are observed. Very good activation of FR4 is obtained with very good backlight test results.

Fifth set of examples:
In a fifth set of examples (details not shown), activation of FR4 and ABS is tested using an activation composition according to the present invention containing 0.005 mol/L Cu2 ⁺ , 0.05 mol/L citric acid, and 1.3 mmol/L sodium borohydride. Again, fully activated FR4 and ABS with excellent backlight test results were obtained.

Sixth set of examples:
In a sixth set (not shown in detail), activation of carbon fiber-containing felt (4.6 mm thickness, approximately 450 g/ ^m2 basis weight, 0.4 ^m2 /g BET surface area) is tested with various activation compositions according to the invention in the first and second sets of examples outlined above. Again, fully nickel-activated felts were obtained in all cases. Furthermore, the activated surfaces showed significant catalytic activity in electrolysis, producing hydrogen and oxygen gases.

Claims (13)

A method of activating the surface of a non-conductive substrate or a carbon fiber-containing substrate for metallization, the method comprising:
(a) preparing the base material;
(b)
(i) a first species of dissolved transition metal ions and additionally metal particles thereof;
(ii) one or more complexing agents;
(iii) one or more reducing agents, permanently or temporarily;
(iv) optionally one or more second species of dissolved metal ions different from said first species;
providing a palladium-free aqueous activation composition comprising:
The first species is copper, and the first species of metal ions and metal particles thereof is 0.30 g based on the total volume of the activation composition and based on the ionic non-specific form. /L to form a total concentration within the range of 6.50 g/L,
- said dissolved transition metal ions and said metal particles of at least said first species exist in reversible equilibrium, with the proviso that
- the metal particles are formed from the dissolved transition metal ions by continuous or semi-continuous reduction with the one or more reducing agents,
- said dissolved transition metal ions are formed from said metal particles by continuous or semi-continuous oxidation of said particles, and - said dissolved transition metal ions and said metal particles are formed, respectively, from precipitated precipitates of said metal particles. is one that repeatedly participates in the reduction and the oxidation so that aggregates are not formed;
process,
(c) contacting the substrate with the activating composition such that a transition metal or transition metal alloy is deposited on the surface of the substrate to provide an activated surface for metallization. fruit,
A method wherein the dissolved transition metal ions are formed from the metal particles by oxidation with ambient air and oxygen gas . 2. The method of claim 1, wherein during and/or after step (c) more than 50% of the metal particles undergo the oxidation. 3. The method of claim 1 or 2, wherein the metal particles of the first species in the activation composition are colloidal metal particles. The metal particles of the first species are in situ in the activated composition by the reduction after and/or while one or more step (c) is performed. 4. The method according to claim 1, wherein the method is formed continuously or semi-continuously. 5. The method of any one of claims 1 to 4, wherein the one or more reducing agents include a boron-containing reducing agent. 6. A method according to any one of claims 1 to 5, wherein the activation composition is substantially free or free of tin ions. The method of any one of claims 1 to 6, wherein the activating composition is substantially free or free of compounds that prevent the oxidation of the metal particles and/or stabilizer compounds for stabilizing the metal particles, other than the complexing agent, the reducing agent, and ambient air and/or oxygen gas. said one or more reducing agents continuously or semi-continuously such that further metal particles are formed continuously or semi-continuously from said dissolved transition metal ions of said first species, respectively. 8. A method according to any one of claims 1 to 7, wherein the method is added to the activation composition. Before step (c), a pretreatment step of the base material:
The method according to any one of claims 1 to 8 , comprising the step of (a-1) treating the substrate with a pretreatment solution containing a nitrogen-containing compound. 1. A method of metallizing an activated surface of a non-conductive substrate or a carbon fiber-containing substrate, the method comprising:
(A) providing the non-conductive substrate or the carbon fiber-containing substrate with the activated surface for metallization obtained by the method according to any one of claims 1 to 9 ; ,
(B) metallizing the activated surface by contacting the activated surface with a first metallization solution such that a first metallization layer is deposited on the activated surface. ,Method. A method of making a palladium-free aqueous activation composition for activating the surface of a non-conductive substrate or a carbon fiber-containing substrate for metallization, the method comprising:
(1)
- a dissolved transition metal ion of the first species,
- providing a starting aqueous solution comprising one or more complexing agents and - optionally one or more dissolved metal ions of a second species different from said first species. There it is,
The first species is copper, and the first species of metal ions and metal particles thereof is 0.30 g based on the total volume of the activation composition and based on the ionic non-specific form. (2) metal particles of at least said first species of dissolved transition metal ions are continuously or semi-continuously in said solution, forming a total concentration within the range of 6.50 g/L to 6.50 g/L; continuously or semi-continuously adding one or more reducing agents to said starting solution such that said metal particles are continuously or semi-continuously added to said starting solution such that said metal particles are A method wherein said first species of dissolved transition metal ions are sequentially oxidized to form said first species of dissolved transition metal ions. continuous or semi-continuous reduction of a first species of dissolved transition metal ions to continuously or semi-continuously form metal particles in situ in a palladium-free aqueous activated composition; the use in combination with continuous or semi-continuous oxidation of said first type of metal particles in equilibrium,
The first species is copper, and the first species of metal ions and metal particles thereof is 0.30 g based on the total volume of the activation composition and based on the ionic non-specific form. /L to form a total concentration within the range of 6.50 g/L ,
Use wherein said dissolved transition metal ions are formed from said metal particles by oxidation by ambient air and oxygen gas . A palladium-free aqueous activation composition for activating the surface of a non-conductive or carbon fiber-containing substrate for metallization, the composition comprising:
(i) a first species of dissolved transition metal ions and additionally metal particles thereof;
(ii) one or more complexing agents;
(iii) one or more reducing agents;
(iv) optionally comprising one or more second species of dissolved metal ions different from said first species;
further contains oxygen gas,
The first species is copper, and the first species of metal ions and metal particles thereof is 0.30 g based on the total volume of the activation composition and based on the ionic non-specific form. /L to form a total concentration within the range of 6.50 g/L,
A composition wherein the dissolved transition metal ions and the metal particles of at least the first species exist in reversible equilibrium.