# US 5,700,523 A · Method for treating metal surfaces using a silicate solution and a silane solution > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,700,523 A - Document ID: US5700523A - Status: Granted - Kind: A - Application number: 08/657,352 - Filed: 1996-06-03 - Granted: 1997-12-23 - Earliest claimed: 1996-06-03 - Assignees: Bulk Chemicals, Inc. - Inventors: Anthony P. Petrole; Jose B. Rivera - Web page: https://patentgrep.com/patent/US5700523A ## CPC - B05D 7/51: {One specific pretreatment, e.g. phosphatation, chromatation, in combination with one specific coating (pretreatment of metallic substrates C23C; pretreatment before coating in general B05D3/00)} - C09D 5/08: Anti-corrosive paints - C23C 22/78: Pretreatment of the material to be coated - C23C 2222/20: Use of solutions containing silanes - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - 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 method for treating a metal surface involves contacting the metal surface with an aqueous silicate solution, contacting the silicate-coated metal surface with an aqueous organo-functional silane solution, and then contacting the silane-coated metal surface with a chrome-free pretreatment. Preferably, the bath containing the aqueous silicate solution also includes a cleaning agent for cleaning the metal surface. Alternatively, the metal surface may be cleaned in a separate step before the metal surface is contacted with the aqueous silicate solution and, optionally, the metal surface is rinsed with water after the metal surface is cleaned and before the metal surface is contacted with the aqueous silicate solution. The silicate-coated metal surface may be rinsed with water before it is contacted with an aqueous organo-functional silane solution. In addition, the silane-coated metal surface may be rinsed with water before it is contacted with a chrome-free pretreatment. As an alternative or in addition to these rinsing steps, excess solution may be removed from the silicate-coated or silane-coated metal surface prior to the subsequent steps. Preferably, the aqueous silicate solution includes water and either sodium silicate or potassium silicate, and the aqueous organo-functional silane solution comprises an aminopropyl silane and water. ## Claims ### Claim 1 A method for treating a metal surface to improve corrosion resistance and paint adhesion of the metal surface, said method comprising the steps of: contacting the metal surface with a first bath, having a pH of at least about 8 and comprising an aqueous silicate solution consisting of water and a compound selected from the group consisting of sodium silicate and potassium silicate in a concentration of from about 0.1 gram/liter to 100 grams/liter, to form a silicate-coated metal surface; contacting the silicate-coated metal surface with a second bath, comprising an aqueous organo-functional silane solution consisting of water and an aminopropyl silane in a concentration of from about 0.1 gram/liter to 100 grams/liter, to form a silane-coated metal surface; and contacting the silane-coated metal surface with a third bath comprising a chrome-free pretreatment consisting of the reaction product of a polymer system having hydroxyl and carboxylic functional groups and a compound of a group IV-B element. ### Claim 2 (depends on 1) The method in accordance with claim 1 further comprising rinsing the silicate-coated metal surface with water prior to the step of contacting the silicate-coated metal surface with said second bath. ### Claim 3 (depends on 1) The method in accordance with claim 1 further comprising removing excess aqueous silicate solution from the silicate-coated metal surface prior to the step of contacting the silicate-coated metal surface with said second bath. ### Claim 4 (depends on 1) The method in accordance with claim 1, wherein the step of contacting the metal surface with a first bath includes cleaning the metal surface and said first bath further comprises a cleaning agent. ### Claim 5 (depends on 4) The method in accordance with claim 4, wherein said cleaning agent is an alkaline-based cleaner. ### Claim 6 (depends on 1) The method in accordance with claim 1 further comprising cleaning the metal surface, to form a cleaned metal surface, prior to the step of contacting the metal surface with said first bath. ### Claim 7 (depends on 6) The method in accordance with claim 6 further comprising rinsing the cleaned metal surface with water prior to the step of contacting the cleaned metal surface with said first bath. ### Claim 8 (depends on 1) The method in accordance with claim 1, wherein: the concentration of said silicate in said first bath is from about 1 gram/liter to 20 grams/liter; and the concentration of said silane in said second bath is from about 1 gram/liter to 20 grams/liter. ### Claim 9 (depends on 1) The method in accordance with claim 1, wherein said first bath has a pH of at least about 9. ### Claim 10 (depends on 1) The method in accordance with claim 1 further comprising rinsing the silane-coated metal surface with water prior to the step of contacting the silane-coated metal surface with said third bath.