Formulation for mordanting polymeric materials prior to coating - Patents.com

Abstract

To provide a formulation of an etching treatment bath for a polymer before metalization or coating of the polymer, by using a known and described technique in a prior art based on using a salt and / or a chelate of a cation Cr (III).SOLUTION: A formulation according to the invention accompanies a Cr(III) salt and / or chelate, Cr(III) being coordinated to at least one or more monodentate ligand, bidentate ligand, tridentate ligand, tetradentate ligand, pentadentate ligand, hexadentate ligand or cross-linking ligand via an oxygen atom, a sulfur atom, a nitrogen atom, or some of these atoms where chromium is coordinated to. When a polymer fragment is etched by an etching formulation described above, for a metalization, a metal coating is applied in a chemical bath, a plating bath, or with a paint or organic coating.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an etching treatment bath for polymers prior to metallization or coating of polymers, using techniques known and described in the prior art, based on the use of salts and / or complexes of cationic Cr(III).

Background Art

[0002] Currently, the technical development and industrial applications of pretreatment baths, treatments, and etching of polymers, mainly ABS, as well as blends of polymers such as ABS polycarbonate, polyamide, polypropylene, and heat-stable polymers, with or without the addition of inorganic fillers and other additives in the polymer substrate, are based on the use of aqueous baths containing chromium salts in the oxidation state VI. The baths generally contain sulfuric acid and chromium(VI) compounds, mainly chromic acid, chromium trioxide, or dichromate, at a concentration of up to 400 gr / l.

[0003] This surface treatment or etching is an important initial treatment, and then a system of multiple functionalized layers of activation, acceleration, electroless nickel deposition, copper, copper electroplating, nickel, and further chromium finishing is applied together with their corresponding intermediate washings, resulting in a plastic metallized on its surface.

[0004] After the important initial processing of the etching surface treatment described above using an organic or coating, the plastic is coated or painted using one of the different methods currently available in the prior art.

[0005] Only a combination of appropriate pretreatment or etching and some further desirable treatments provides all the important requirements necessary for each application, and the initial etching treatment is an essential factor in the overall process.

[0006] Chromium salts in oxidation state VI used in etching have been proven to be toxic and carcinogenic to humans, leading to interest in alternatives to the use of these chromium(VI) salts, specifically in polymer processing and etching baths.

[0007] As shown in U.S. Patent No. 8,603,352 (B1) and U.S. Patent Application Publication No. 2013,0186,774, different alternatives have been proposed to baths containing Cr salts (VI) for other chemical oxidizers, mainly salts of Mn(VII), Mn(VI), and even salts of Mn(III) in acidic and basic media.

[0008] However, these systems based on Mn salts do not produce the same adhesion, resulting in metallization or late coating of the polymer pieces and requiring very complex cleaning to remove the reduction products of the Mn salt. The baths are also unstable over time and do not last long in industrial applications.

[0009] Alternatively, systems based on hydrogen peroxide, such as German Patent No. 19740431(C1), iron and / or copper peroxides and salts, such as U.S. Patent No. 6559242(B1), anionic complexes with transition metal chloride ligands (U.S. Patent No. 4568571(A)), organometallic compounds of transition metals in organic solvents (European Patent No. 0081129(A1)), and salts of transition metal chlorides or nitrates without the use of complexes in a weakly acidic aqueous medium (U.S. Patent Application Publication No. 20070099425(A1)) have been proposed.

[0010] Currently, in all cases, results applicable to the final adhesion requirements demanded by automated sectors, particularly those obtainable by treatments based on Cr(VI) salts, have not been found. A peer-reviewed article on this topic was recently published: Plating on acrylonitrile-butadiene-styrene(ABS)plastic: A review. Journal of Materials Science 2016, 51, 3657-3674. Therefore, in the prior art, there is a need for efficient etching baths that result in adhesion to other types of metallization or coatings of polymers, bath stability over time and use, safety properties, non-toxicity to people and the environment, ease of recovery, recycling, or removal of those treatment baths without Cr(VI) under environmentally appropriate conditions. [Overview of the Initiative]

[0011] The object of the present invention is the pretreatment, processing, and / or etching of polymers by using an aqueous solution containing a salt and / or a chromium(III) complex in an acidic medium.

[0012] The present invention is based on the use of a cation Cr(III) that is added like a salt and chemically coordinates to at least one or more monodentate, bidentate, tridentate, tetradentate, pentate, hexadate, or bridging ligands that coordinate to chromium via an oxygen atom, sulfur atom, or nitrogen atom.

[0013] This process is applied to organic polymers to modify their surfaces both physically and chemically, making it possible to produce coatings on the polymer surface that can be deposited or metallized by techniques currently described in the prior art. [Modes for carrying out the invention]

[0014] Coating polymers with metals via a chemical bath, or with organic coatings, requires prior etching, so the surface of the polymer to be coated must be sufficiently adhesive to meet the application requirements of the final product.

[0015] The polymers used in this etching process are thermoplastic polymers such as ABS, ABS blends with other polymers such as polycarbonate, polyamide, PVC, polyester, polyacetal, and polyolefin, heat-stable polymers such as epoxy resins, unsaturated polyester resins, and vinyl ester epoxy resins, or elastomers such as SBR and EPDM rubber, or different types of thermoplastic elastomer polymers available on the market. The polymers may contain different types of inorganic fillers such as quartz, calcium carbonate, wollastonite, silicate, and talc, as well as corresponding additives required for processing them in different techniques used to manufacture objects, plates, or forms in heat-stable polymers or elastomer polymers, such as extrusion, injection, molding on a hot plate, or other methods.

[0016] Polymer surface treatment or etching is a process that has several prior requirements, including a specific composition of the treatment or etching bath, and the action or treatment of these baths at a controlled temperature and time.

[0017] Requirements for etching: The surface of the substrate to be pre-treated shall be free from contaminants, grease, corrosive products, and other materials. Therefore, proper preparation of the base substrate is a recommended but not strictly required requirement before processing. On-the-job preparation of substrates is well known in the prior art.

[0018] The bath composition used in etching is aqueous. The bath is prepared by adding a salt or chromium(III) complex and is based on the use of at least one or more monodentate, bidentate, tridentate, tetradentate, pentate, hexadentate, or bridging ligands that coordinate to chromium via the oxygen, sulfur, or nitrogen atoms of the ligand.

[0019] In particular, ligands that can be used with chromium in oxidized state (III) include formate, acetate, propanoate, butanoate, benzoate, phenylacetate, phenylpropionate, cyanate, alkylbenzoate, pyruvate, levulinate, citrate, isocitrate, aconitate, trimellitate, glycinate, valveate, leucinate, threoninate, lysinate, tryptophanate, histidanate, phenylalaninate, isoleucinate, arginine, and methionine. Sodium, alaninate, prolineate, serineate, cysteinate, asparaginate, glutamineate, tyrosinate, aspartate, polyaspartate, glutamate, cysteinate, homocysteinate, olmitinate, nicotinate, oxalate, propanodioate, butanedioate, pentanodioate, hexanodioate, malate, fumarate, phthalate, isophthalate, terephthalate, tartrate, itaconate, mesaconate, citraconate, glycolate, latate Cutete, mandelate, salicylate, gluconate, ethylenediamine tetraacetate, nitrilotriacetate, iminodisuccinate, ethylenodiamine disuccinate, methylglycine diacetate, N,N,glutamate diacetate, cyclohexylenedinitrilotetraacetate, diethylenotriamainapentaacetate, aminoethylethylene glycol tetraacetate, triethylenetetra Minahexaacetate (tryethylentetraminahexaacetate), dihydroxyethylglycinate, iminodiacetate, oxamate, nitrilotripionate, etilenodiaminedipropionate, thiodipropionate, dithiodipropionate, aminopropanoate, aminopentanoate, aminohexanoate, 2-aminobenzoate, 3-aminobenzoate, 4-aminobenzoate, 3-cyclohexylamine-propylamine, etilenodiamine, 1,3-diaminopropane, dimethylaminopropylamine, diethylaminopropylamine, bis(3-aminopropyl)-methylamine, diethylenotriamine, dipropylenotraimine, triethylenetetramine, tetraethylenopentamine, polyamine, 3-(2-aminoethyl)aminopropylamine, N,N'-bis(3-aminopropyl)ethilenodiamine, neopentante diamine, cyclohexanodiamine, hexano-1,6-diamine, imidazole, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, N-(3-aminopropyl)-imidazole, pyrazole, nicyanamide, bipyridine, phenanthroline, or blends thereof.

[0020] The ligands used are preferably formate, acetate, propionate, glycinate, arginine, aspartate, polyaspartate, glutamate, nicotinate, oxalate, propanodioate, butanedioate, pentanodioate, hexanodioate, malate, fumarate, phthalate, salicylate, tartrate, citrate, glycolate, lactate, ethylenediaminetetraacetate, nitrilotriacetate, and 2-aminobenzoate. The ligands used are most preferably oxalate, propanodioate, butanedioate, malate, fumarate, phthalate, glycolate, lactate, salicylate, glycolate, glutamate, or a blend thereof.

[0021] The chromium(III) complex contained in the bath can be added to the bath in the form of a prepared and isolated chromium(III) complex with the above ligands, as suggested in the scientific literature on oxalate-type complexes, for example, "Complex Ions of Chromium.III. Reactions between Hexaquochromium(III) and Oxalate lons," Randall E. Hamm, Robert E. Davis J.Am.Chem.Soc., 1953, 75, pp3085-3089 (1953).

[0022] Cr(III) complexes can also be formed in situ in the bath by the separate addition of the chromium(III) salt and ligands constituting the desired complex, as suggested, for example, for the fumarate-type complex described in U.S. Patent No. 3900689.

[0023] When chromium(III) complexes are formed in situ, the starting salts for these complexes may be inorganic or organic anionic salts, such as chlorides, bromides, perchlorates, hydroxides, oxides, sulfates, sulfites, sulfides, nitrates, nitrites, phosphates, diphosphates, metaphosphates, polyphosphates, borates, silicates, formates, acetates, lactates, methanesulfonates, ethanesulfonates, propanesulfonates, butanesulfonates, carboxhelates, alkyl phosphates, or blends thereof. When these salts are added to a water bath, they are added to the bath in their protonated form, or in the form of an alkali or alkaline earth metal salt, or in their free form, in order to form the complex. In this way, the chromium(III) complex required for the etching bath is obtained.

[0024] Finally, the Cr(III) complex required in the etching bath can also be obtained by chemical reaction or by the reduced form of the ligand used and by the addition of the Cr(VI) compound to the bath, which is reduced to the oxidized complex (III) by the direct action of the ligand formed together when the complex is a reducing agent, or by adding different reducing agents to the ligand, such as ascorbic acid, ascorbate, thiosulfate, sulfite, sulfide, nitrite, phosphite, hypophosphite, formaldehyde sulfoxylate, dithionite, oxalate, alkali metal or alkaline earth metal carboxhlate, hydrazine and its derivatives, hydroxylamine, or any other reducing agent known in the prior art.

[0025] The concentration of the Cr(III) complex present in the bath may be 2 mM to 2 M, more preferably 5 mM to 1 M, and even more preferably 0.01 M to 0.4 M.

[0026] The suggested Cr(III) complex is used in an acidic aqueous medium, and the acid contained in the etching bath may be sulfuric acid, aminosulfate (sulfamic acid), phosphoric acid, diphosphate, metaphosphate, polyphosphate, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, alkanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, cumenesulfonic acid, alkylbenzenesulfonic acid, monoalkyl phosphate, dialkyl phosphate, isethionic acid, perchloric acid, chloric acid, nitric acid, trifluorofluoromethasulfonic acid, trifluoroacetic acid, tetrafluoroboric acid, hexafluorophosphate, hexafluorosilicic acid, hydrofluoric acid, boric acid, or a blend thereof. Preferably, the acid present in the etching bath may be sulfuric acid, phosphoric acid, diphosphate, metaphosphate, polyphosphate, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, cumenesulfonic acid, alkylbenzenesulfonic acid, monoalkyl phosphoric acid, dialkyl phosphoric acid, or a blend thereof. More preferably, the acid present in the etching bath may be sulfuric acid, phosphoric acid, or a blend thereof.

[0027] The concentration of the acid in the etching bath can be from 10% to a maximum of 98%, preferably from 40% to 95%, more preferably from 55% to 92%, considering the total acid contained in mass / mass percent, and the balance is a Cr(III) complex and water. This total acid can be composed of a mixture of two or more acids.

[0028] The use temperature of the etching bath can vary from 10°C to 95°C, more preferably from 15°C to 80°C, and even more preferably from 20°C to 75°C. To reach the working temperature, the treatment tank is heated or cooled by applying any suitable technique for that purpose until the ideal working temperature is maintained.

[0029] Fragments of any shape and size of the polymer to be treated in the etching bath are immersed in the etching bath for a period of from 30 seconds to 1 hour, preferably from 1 minute to 45 minutes, or more preferably from 2 minutes to 30 minutes.

[0030] After the etching process referred to in the present invention, the necessary washing step is carried out with water, an aqueous solution, or an organic liquid having the properties known in the current prior art.

[0031] After washing, through a chemical bath having the necessary properties, the processes necessary to obtain a metal coating through wet processing are carried out.

[0032] Alternatively, when a polymer coating such as a varnish or paint is placed on the treated fragment after washing, the fragment may or may not be dried.

Examples

[0033] The substrates used in the following examples are substrates obtained by injection of the corresponding thermoplastic polymers: ABS, ABS-polycarbonate, polyamide 6, polyamide 6 having 20% wollastonite inorganic filler, polypropylene, or polypropylene having 20% talc inorganic filler.

[0034] The thermally stable substrates are cured by methods known in the conventional art, and these are unsaturated polyester resins having 40% glass fibers and epoxy resins having 40% glass fibers.

[0035] In all cases, the substrate is cleaned before etching. Cleaning is performed by immersion in a water bath, then in a bath of a 1% aqueous solution of sodium dodecyl sulfate, and then rinsing twice by immersion in two water baths. The purpose of this cleaning is to remove dirt and grease from the substrate and / or prepare the surface for etching. Depending on the processing required to prepare the fragments, this cleaning may be avoided.

[0036] The etching process is carried out using the corresponding baths shown in the following examples.

[0037] After etching, the part is rinsed at least twice by immersing it in a water bath.

[0038] When the polymer is etched, self-catalyzed electroless nickel, also known as electroless nickel, is deposited by a process known in the prior art. Treatment by immersion in an activation bath at 25°C for 2 minutes. Rinsing in a water bath. Treatment in an accelerator bath at 25°C for 2 minutes. Rinsing in a water bath. Immersion bath at 29°C for 8 minutes for electroless nickel metallization. Two washes by immersion in a water bath.

[0039] Similarly, etching is performed and the substrate is dried, resulting in the polymer being coated with an organic base or paint.

[0040] Example 1 For reference regarding the results obtained by etching, etching is performed in a bath based on the use of a Cr(VI) salt containing the following composition. The etching bath contains 380 gr / L of chromic acid and 400 gr / L of concentrated sulfuric acid.

[0041] The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0042] Example 2 An etching bath based on Cr(III) salt, in which the ligand coordinating with chromium is acetate, and prepared by a solution of 62% H2O; 4% chromium acetate(III); and 34% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0043] Example 3 An etching bath based on Cr(III) salts, in which benzoate is a ligand coordinated with chromium, prepared by a solution of 40% H2O; 3% chromium benzoate(III); and 57% methanesulfonic acid. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0044] Example 4 An etching bath based on Cr(III) salts, in which the ligand coordinated to chromium is glycinate, and prepared by a solution of 21% H2O; 2.5% chromium glycinate(III); and 65.5% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0045] Example 5 An etching bath based on Cr(III) salts, in which an aminoalkanoate is a ligand coordinated with chromium, prepared by a solution of 21% H2O; 2.2% CrCl3·6H2O; 1.3% aminohexanoic acid; 36.5% H3PO4 (75% in water); and 39% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0046] Example 6 An etching bath based on Cr(III) salts, prepared by a solution of 17% H2O; 1.2% Cr(NO3)3.9H2O; 2.6% citric acid; 39.7% H3PO4 (75% in water); and 39.5% H2SO4, with a citrate ligand coordinated to chromium. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0047] Example 7 An etching bath based on Cr(III) salts, prepared by a solution of 19% H2O; 0.8% Cr(NO3)3.9H2O; 1.1% triethylenetetramine; 38.4% H3PO4 (75% in water); and 40.7% H2SO4, with triethylenetetramine as the ligand coordinated to chromium. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0048] Example 8 An etching bath based on Cr(III) salt, in which the ligand coordinated with chromium is a thiodipropionate, is prepared by a solution of 18.5% H2O; 0.7% CrCl3·6H2O; 0.9% thiodipropionic acid; 38% H3PO4 (75% in water); and 41.9% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0049] Example 9 An etching bath based on Cr(III) salt, in which the ligand coordinated with chromium is ethylenediaminetetraacetate (EDTA), and prepared by a solution of 18% H2O; 0.6% Cr(NO3)3.9H2O; 0.3% ethylenediaminetetraacetic acid; 39.7% H3PO4 (75% in water); and 41.4% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0050] Example 10 An etching bath based on Cr(III) salts is prepared by a solution of 18.3% H2O; 0.6% Cr(NO3)3.9H2O; 0.5% disodium ethylenediaminetetraacetic acid; 39.2% H3PO4 (75% in water); and 41.4% H2SO4, with ethylenediaminetetraacetate (EDTA) as the ligand coordinated to chromium. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0051] Example 11 An etching bath based on Cr(III) salt, in which the ligand coordinated with chromium is ethylenediaminetetraacetate (EDTA), and prepared by a solution of 18% H2O; 0.6% Cr(NO3)3.9H2O; 0.3% ethylenediaminetetraacetic acid; 39.7% H3PO4 (75% in water); and 41.4% H2SO4. The fragment to be etched is left in the bath at a temperature of 40°C for 3 minutes.

[0052] Example 12 An etching bath based on Cr(III) salt, in which the ligand coordinated to chromium is ethylenediaminetetraacetate (EDTA), and prepared by a solution of 18% H2O; 2% Cr(NO3)3.9H2O; 1% ethylenediaminetetraacetic acid; 35.5% methanesulfonic acid (75% in water); and 43.5% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0053] Example 13 An etching bath based on Cr(III) salts is prepared by a solution of 18% H2O; 0.6% Cr(NO3)3.9H2O; 0.3% fumaric acid; 39.7% H3PO4 (75% in water); and 41.4% H2SO4, with fumarate as the ligand coordinated to chromium. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0054] Example 14 An etching bath based on Cr(III) salt, in which the ligand coordinated with chromium is an oxalate compound consisting of a solution of 18% H2O; 0.9% Cr(NO3)3.9H2O; 0.6% oxalic acid H2C2O4.2H2O; 39.7% H3PO4; and 40.8% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0055] Example 15 An etching bath based on a Cr(III) salt, in which the ligand coordinated with chromium is an oxalate compound consisting of a solution of 17.7% H2O; 1.2% Cr(NO3)3.9H2O; 0.6% oxalic acid H2C2O4.2H2O; 39.7% H3PO4 (75%); and 40.8% H2SO4. The fragment to be etched is left in the bath at a temperature of 25°C for 15 minutes.

[0056] Example 16 An etching bath based on Cr(III) salt, prepared by a solution of 18% H2O; 0.6% Cr2O3; 0.8% salicylic acid; 39.7% H3PO4 (75% in water); and 40.9% H2SO4, with a salicylate ligand coordinated to chromium. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0057] Example 17 An etching bath based on Cr(III) salt, prepared by a solution of 18% H2O; 0.6% Cr2O3; 0.8% salicylic acid; 39.7% H3PO4 (75% in water); and 40.9% H2SO4, with a salicylate ligand coordinated to chromium. The fragment to be etched is left in the bath at a temperature of 60°C for 3 minutes.

[0058] Example 18 An etching bath based on Cr(III) salts, prepared by a solution of 18% H2O; 0.6% Cr2(SO4)3·H2O; 2% calcium gluconate; 38% H3PO4 (75% in water); and 41.4% H2SO4, with a ligand coordinated to chromium. The fragment to be etched is left in the bath at a temperature of 25°C for 3 minutes.

[0059] The metallized fragments undergo an adhesion test using the cross-cut test (ISO 2409), one of the commonly used methods to determine the adhesion of coatings on polymers. The adhesion results are scored from 0 to 5, with 0 indicating excellent adhesion, and the peeling method follows standard DIN 53494.

[0060] The adhesion results of the metal layers obtained after etching and metallization of the fragments are shown in the table below.

[0061] [Table 1]

[0062] The fragments coated with paint or an organic coating are prepared after bath treatment by drying them in a 40°C airflow for 2 hours, and then coated with an airbrush. The paint used is a standard type called 100% solid based on triethylene glycol diacrylate, and is UV curing, applied according to the manufacturer's recommendations.

[0063] Adhesion results of paints tested under ISO2409:

[0064] [Table 2]

Claims

1. 1. An acid etching bath formulation comprising an acid and a Cr(III) coordination complex, wherein the concentration of the acid in the etching bath is 20% to 98% by weight.

2. 10. The formulation of claim 1, wherein the chromium(III) coordination complex comprises at least one or more ligands selected from monodentate, bidentate, tridentate, tetradentate, pentadentate, hexadentate, or bridging ligands coordinated to chromium through an oxygen atom, a sulfur atom, or a nitrogen atom, or a combination thereof.

3. The ligand may be selected from the group consisting of formate, acetate, propanoate, butanoate, benzoate, phenylacetate, phenylpropionate, cyanamate, alkylbenzoate, pyruvate, levulinate, citrate, isocitrate, aconitate, trimellitate, glycinate, valinate, leucinate, threoninate, lysinate, tryptophanate, histidate, phenylalaninate, isoleucinate, argininate, methioninate, alaninate, and prolinate. , serinate, cysteinate, asparaginate, glutamate, tyrosinate, aspartate, polyaspartate, glutamate, cysteinate, homocysteinate, olmitinate, nicotinate, oxalate, propanodioate, butanedioate, pentanodioate, hexanodioate, maleate, fumarate, phthalate, isophthalate, terephthalate, tartrate, itaconate, mesaconate, citraconate, glycolate, lactate, mandelate , salicylate, gluconate, ethylenediaminetetraacetate, nitrilotriacetate, iminodisuccinate, ethylenodiaminedisuccinate, methylglycine diacetate, N,N, glutamate diacetate, cyclohexylene dinitrilotetraacetate, diethylenotriamainapentaacetate, aminoethyl ethylene glycol tetraacetate, triethylenetetraminahexaacetate Acetate (tryethylentetraminahexaacetate), dihydroxyethyl glycinate, iminodiacetate, oxamate, nitrilotripropionate, ethylenediamine dipropionate, thiodipropionate, dithiodipropionate, aminopropanoate, aminopentanoate, aminohexanoate, 2-aminobenzoate, 3-aminobenzoate, 4-aminobenzoate, 3-cyclohexylamine-propylamine, ethylenediamine, 1,3. The formulation of claim 2, wherein the amine is selected from 3-diaminopropane, dimethylaminopropylamine, diethylaminopropylamine, bis(3-aminopropyl)methylamine, diethylenetriamine, dipropylenotraimine, triethylenetetramine, tetraethylenopentamine, polyamines, 3-(2-aminoethyl)aminopropylamine, N,N'-bis(3-aminopropyl)ethylenediamine, neopentantediamine, cyclohexanodiamine, hexano-1,6-diamine, imidazole, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, N-(3-aminopropyl)imidazole, pyrazole, nicyanamide, bipyridine, and phenanthroline. ,

4. 3. The formulation of claim 2, wherein the ligand is selected from formate, acetate, propionate, glycinate, argininate, aspartate, polyaspartate, glutamate, nicotinate, oxalate, propanedioate, butanedioate, pentanedioate, hexanedioate, maleate, fumarate, phthalate, salicylate, tartrate, citrate, glycolate, lactate, gluconate, ethylenediaminetetraacetate, nitrilotriacetate, and 2-aminobenzoate.

5. 3. The formulation of claim 2, wherein the ligand is selected from oxalate, propanedioate, butanedioate, maleate, fumarate, phthalate, glycolate, lactate, salicylate, glycinate, glutamate, or mixtures thereof.

6. 6. The formulation of claim 1, wherein the concentration of the Cr(III) complex is in the range of 2 mM to 2 M.

7. 6. The formulation of claim 1, wherein the concentration of the Cr(III) complex is in the range of 5 mM to 1 M.

8. 6. The formulation of claim 1, wherein the concentration of the Cr(III) complex is in the range of 0.01 M to 0.4 M.

9. 9. The formulation of any one of claims 1 to 8, wherein the acid in the etching bath is selected from sulfuric acid, aminosulfuric (sulfamic) acid, phosphoric acid, diphosphoric acid, metaphosphoric acid, polyphosphoric acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, cumenesulfonic acid, alkylbenzenesulfonic acids, monoalkylphosphoric acid, dialkylphosphoric acid, isethionic acid, perchloric acid, chloric acid, nitric acid, trifluorofluoromethasulfonic acid, trifluoroacetic acid, tetrafluoroboric acid, hexafluorophosphoric acid, hexafluorosilicic acid, hydrofluoric acid, boric acid, or mixtures thereof.

10. 9. The formulation of any one of claims 1 to 8, wherein the acid in the etching bath is selected from sulfuric acid, aminosulfuric (sulfamic) acid, phosphoric acid, diphosphoric acid, metaphosphoric acid, polyphosphoric acid, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, cumenesulfonic acid, alkylbenzenesulfonic acids, monoalkylphosphoric acids, dialkylphosphoric acids, or mixtures thereof.

11. 9. The formulation according to any one of claims 1 to 8, wherein the acid in the etching bath is selected from sulfuric acid, phosphoric acid, or mixtures thereof.

12. 12. The formulation according to any one of claims 1 to 11, wherein the weight percentage of acid is between 65% and 98%.

13. 12. The formulation according to any one of claims 1 to 11, wherein the weight percentage of acid is between 40% and 95%.

14. 12. The formulation according to any one of claims 1 to 11, wherein the weight percentage of acid is between 55% and 92%.

15. A thermoplastic, thermoset, or elastomeric polymeric material exposed to an acid etching bath formulation comprising an acid and a Cr(III) coordination complex, wherein the concentration of the acid in the etching bath is 20% to 98% by weight.

16. A thermoplastic, thermoset, or elastomeric polymeric material exposed to an acid etching bath formulation comprising an acid and a Cr(III) coordination complex, wherein the concentration of the acid in the etching bath is between 20% and 98% by weight, and further exposed to a metallized or organic coating.