# US 9,752,074 B2 · Chromium-free pickle for plastic surfaces > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,074 B2 - Document ID: US9752074B2 - Status: Granted - Kind: B2 - Application number: 14/702,020 - Filed: 2015-05-01 - Published: 2016-01-28 - Granted: 2017-09-05 - Earliest claimed: 2007-08-10 - Applicants: Enthone Inc. - Inventors: Mark Peter Schildmann; Ulrich Prinz; Christoph Werner - Web page: https://patentgrep.com/patent/US9752074B2 ## CPC - C09K 13/04: containing an inorganic acid - B44C 1/227: {by etching} - C08J 7/14: with acids, their salts or anhydrides - C23C 18/24: using acid aqueous solutions - C08J 2355/02: Acrylonitrile-Butadiene-Styrene [ABS] polymers - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - B44C: PRODUCING DECORATIVE EFFECTS (processes for applying liquids or other fluent materials to surfaces, in general B05D; shaping of plastics or substances in a plastic state B29C; printing processes to produce transfer pictures B41M3/12; thermographic duplication or marking methods B41M5/00); MOSAICS; TARSIA WORK (imitation of mosaic or tarsia work patterns B44F11/04); PAPERHANGING {(labels G09F; multi-step processes for making paper labels or tags B31D1/02)} - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract A pickling solution for the surface pre-treatment of plastic surfaces in preparation for metallization, the solution comprising a source of Mn(VII) ions; and an inorganic acid; wherein the pickling solution is substantially free of chromium (VI) ions, alkali ions, and alkaline-earth ions. ## Claims ### Claim 1 A process for pickling plastic surfaces comprising: a) dispersing a manganese salt in an acid solution in an oxidative cell to produce Mn(VII) ions; and b) contacting the plastic surface to be pickled with an acidic treatment solution, the acidic treatment solution comprising the Mn(VII) ions and an inorganic acid, wherein the inorganic acid is at least one acid selected from the group consisting of phosphoric acid, peroxomonophosphoric acid, peroxodiphosphoric acid, sulfuric acid, peroxomonosulfuric acid, and peroxodisulfuric acid; wherein the acidic treatment solution is substantially free of chromium ions, alkali ions and alkaline earth ions; and wherein the acid used in the acid solution of the oxidative cell comprises the same acid as the inorganic acid in the acidic treatment solution. ### Claim 2 (depends on 1) The process for pickling ABS plastic surfaces according to claim 1, wherein the acid treatment solution comprises silver ions. ### Claim 3 (depends on 1) The process for pickling ABS plastic surfaces according to claim 1, wherein the acidic treatment solution in the oxidation cell is maintained at a temperature in the range of 20° C. to 90° C. ### Claim 4 (depends on 1) The process for pickling ABS plastic surfaces according to claim 1, further comprising the step of metallizing the pickled ABS plastic surfaces. ### Claim 5 (depends on 1) The process for pickling ABS plastic surfaces according to claim 1, wherein the ABS plastic surfaces comprise an ABS plastic or an ABS plastic blend. ### Claim 6 A pickling solution for the surface pre-treatment of plastic surfaces in preparation for metallization, the solution comprising: a source of Mn(VII) ions; an inorganic acid, the inorganic acid comprising 800 g/l to 1400 g/l sulfuric acid; wherein the pickling solution is substantially free of chromium (VI) ions, alkali ions, and alkaline-earth ions; and wherein the formation of insoluble Mn(III)-compounds is avoided. ### Claim 7 (depends on 6) The pickling solution according to claim 6 wherein the source of Mn(VII) ions provides Mn(VII) ions at a concentration between 0.001 and 0.5 mol/l. ### Claim 8 (depends on 6) The pickling solution according to claim 6 wherein the inorganic acid has a concentration between 1 and 18.5 mol/l. ### Claim 9 (depends on 6) The pickling solution according to claim 6 further comprising ions of one or more elements from the group consisting of Ag, Bi, V, Mo, and Cu. ### Claim 10 (depends on 9) The pickling solution according to claim 9 further comprising silver ions. ### Claim 11 (depends on 6) The pickling solution according to claim 6 comprising between 0.001 and 2.0 mol/l ions of one or more elements from the group consisting of Ag, Bi, V, Mo, and Cu. ### Claim 12 (depends on 6) The pickling solution of claim 6 further comprising a wetting agent. ### Claim 13 (depends on 6) The pickling solution of claim 6 further comprising a defoamer. ### Claim 14 (depends on 6) The pickling solution of claim 6 wherein the Mn(VII) ions are obtained by means of an oxidation cell from a Mn-ion of an oxidation state lower than VII. ### Claim 15 (depends on 14) The pickling solution according to claim 14, wherein the solution for the oxidative production of Mn(VII) ions is an acidic solution. ### Claim 16 (depends on 14) The pickling solution according to claim 14 wherein the solution for the oxidative production of Mn(VII) ions includes as a source of Mn ions of an oxidation stage lower than (VII) at least one manganese compound selected from the group of MnCO3, MnSO4, MnO, MnCl2, Mn(CH3COO)2, Mn(NO3)2, Mn2O3, MnPO4, MnO(OH), Mn(CH3COO)3 and MnF3 and MnO2. ### Claim 17 (depends on 16) The pickling solution according to claim 16 wherein the solution for the oxidative production of Mn(VII) ions includes at least one acid from the group consisting of phosphoric acid, peroxomonophosphoric acid, peroxodiphosphoric acid, sulfuric acid, peroxomonosulfuric acid and peroxodisulfuric acid. ### Claim 18 A process for pickling plastic surfaces comprising: a) providing an oxidation cell comprising an anode space and a cathode space separated from each other by a membrane capable of allowing ions to pass through; b) disposing an anolyte in the anode space, the anolyte comprising a concentrated acid and a Mn ion releasing compound; c) disposing a catolyte in the cathode space, the catolyte comprising a diluted mineral acid; d) applying a current density to galvanically oxidatively form an acidic Mn(VII) containing treatment solution; and e) contacting the plastic surface to be pickled with the acidic Mn(VII) containing treatment solution inside the anode space or a working container connected to the anode space; wherein the acidic treatment solution is substantially free of chromium ions, alkali ions and alkaline earth ions. ### Claim 19 (depends on 15) The process for pickling ABS plastic surfaces according to claim 15, wherein the acidic treatment solution further comprising ions of one or more elements selected from the group consisting of Ag, Bi, V, Mo, and Cu. ### Claim 20 (depends on 18) The process for pickling ABS plastic surfaces according to claim 18, wherein the acidic treatment solution in the oxidation cell is maintained at a temperature in the range of 20° C. to 90° C.