# US 10,870,923 B2 · Can pretreatment for improved coat adhesion > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,870,923 B2 - Document ID: US10870923B2 - Status: Granted - Kind: B2 - Application number: 15/346,787 - Filed: 2016-11-09 - Published: 2017-02-23 - Granted: 2020-12-22 - Earliest claimed: 2012-11-08 - Assignees: Henkel AG & Co. KGaA - Applicants: Henkel AG & Co. KGaA - Inventors: Joerg Riesop - Web page: https://patentgrep.com/patent/US10870923B2 ## CPC - C23C 22/34: containing fluorides or complex fluorides - B21D 22/201: {Work-pieces; preparation of the work-pieces, e.g. lubricating, coating} - B21D 51/263: {Flanging} - C23C 22/361: {containing titanium, zirconium or hafnium compounds} - C23C 22/73: characterised by the process - C23C 22/83: Chemical after-treatment - B21D 51/26: cans or tins; Closing same in a permanent manner (making outlet arrangements B21D51/38; welding or soldering B23K) - 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) - B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F) ## Abstract The invention relates to use of an aqueous composition for pretreating can body stock, whereby an inorganic-organic conversion layer is formed, which effects outstanding sliding behavior of the shaped can body stock and in addition offers an outstanding holding primer for subsequent coating. The invention comprises a process in which can body stock which is deep-drawn to form a half-open can cylinder, before further shaping processes, is contacted with an acidic aqueous composition which contains water-soluble inorganic compounds of Zr, Ti, Si, Hf or Ce, water-soluble polymers having carboxyl groups or hydroxyl groups and also a dispersed wax. Both outer and inner surfaces of metallic can cylinders can be pretreated in the process. The invention also relates to an acidic aqueous composition for use in the pretreatment process, which contains water-soluble polymers selected from condensation products of glycoluril and aldehydes. ## Claims ### Claim 1 A process for surface-treating a can cylinder which is deep-drawn from a metal sheet and is open at one end, in which process: 1.) at least an outer circumferential surface of the can cylinder is contacted with an acidic aqueous composition which contains: a) at least one water-soluble compound of elements Zr, Ti, Si, Hf, and/or Ce; b) at least one water-soluble organic resin, which comprises at least carboxyl groups or hydroxyl groups, having an acid value and/or a hydroxyl value wherein a sum of the acid value and/or hydroxyl value of the at least one water-soluble organic resin is at least 50 mg KOH/g, wherein b) comprises condensation products of glycoluril with primary aldehydes, the condensation products having a degree of alkylation below 20%; and c) at least one dispersed wax; and 2.) wherein at least the outer circumferential surface of the can cylinder that is open at one end is provided with a protective coating after being brought into contact with the acidic aqueous composition; and, optionally, after a directly subsequent flushing step. ### Claim 2 (depends on 1) The process according to claim 1, wherein the water-soluble compounds of component a) of the acidic aqueous composition are selected from fluoro complexes of the elements Zr, Ti, and/or Si. ### Claim 3 (depends on 1) The process according to claim 1, wherein content of water-soluble compounds of the elements Zr, Ti, Si, Hf, and/or Ce of component a) in the acidic aqueous composition is in a range of 0.01 to 1 g/L with respect to a total content of said elements. ### Claim 4 (depends on 1) The process according to claim 1, wherein the water-soluble organic resin of component b) of the acidic aqueous composition is selected from polymers or copolymers based on vinyl ethers, vinyl alcohols, (meth)acrylic acid, maleic acid, or fumaric acid, from hydroxyl group-containing polyesters, and from condensation products of glycoluril or melamine with aldehydes. ### Claim 5 (depends on 1) The process according to claim 1, wherein content of water-soluble organic resins of component b) in the acidic aqueous composition is in range of 0.1 to 50 g/L. ### Claim 6 (depends on 1) The process according to claim 1, wherein the wax in the acidic aqueous composition is selected from synthetic waxes. ### Claim 7 (depends on 1) The process according to claim 1, wherein content of dispersed waxes in the acidic aqueous composition is in a range of 0.1 to 10 g/L. ### Claim 8 (depends on 1) The process according to claim 1, wherein the acidic aqueous composition additionally contains phosphate ions in an amount of at least 0.1 g/L, but not more than 10 g/L of phosphate ions. ### Claim 9 (depends on 1) The process according to claim 1, wherein the acidic aqueous composition has a pH value of not less than 2, and not greater than 6. ### Claim 10 (depends on 1) The process according to claim 1, wherein after bringing the can cylinder that is open at one end into contact with the acidic aqueous composition and before application of the protective coat onto the outer circumferential surface of the can cylinder, there are no further wet-chemical pretreatment steps that are not flushing steps. ### Claim 11 (depends on 1) The process according to claim 1, wherein the can cylinder is not shaped in a rim region that is open at one end. ### Claim 12 (depends on 1) The process according to claim 1, wherein the can cylinder is deep-drawn from tinplate, steel sheet, or aluminum sheet. ### Claim 13 (depends on 1) A production process for can cylinders, wherein: A. a circular blank of a metal sheet is deep-drawn to form a can cylinder that is open at one end; B. the can cylinder that is open at one end is pretreated and coated in a process according to claim 1; and C. the pretreated and coated can cylinder is drawn-in in a rim region that is open at one end in order to taper a diameter of the can cylinder and/or is shaped to form a flange in the rim region that is open at one end. ### Claim 14 A process for surface-treating a can cylinder which is deep-drawn from a metal sheet and is open at one end, in which process: 1.) at least an outer circumferential surface of the can cylinder is contacted with an, acidic aqueous composition which comprises: a) 0.005 to 0.5 wt. % of water-soluble fluoro complexes of elements Zr, Ti, and/or Si; b) 0.05 to 3 wt. % of water-soluble resins selected from condensation products of glycoluril with aldehydes, said resins having an acid value and/or hydroxyl value wherein a sum of the acid value and/or hydroxyl value of the resins is at least 50 mg KOH/g; and c) 0.1 to 5 wt. % of oxidized polyalkylene waxes, said composition having a pH value in a range of 2 to 5; and 2.) wherein at least the outer circumferential surface of the can cylinder that is open at one end is provided with a protective coating after being brought into contact with the acidic aqueous composition; and, optionally, after a directly subsequent flushing step.