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WO-2026090963-A1 - ACIDIC CR-FREE AQUEOUS COMPOSITION AND PROCESS FOR TREATING A METAL SURFACE

WO2026090963A1WO 2026090963 A1WO2026090963 A1WO 2026090963A1WO-2026090963-A1

Abstract

The present invention relates to an acidic Cr-free aqueous composition for treating a metal surface, comprising: (A) at least one organosilane having at least one hydrolysable substituent and one or three non-hydrolysable substituents; (B) at least one organic polymer based on phenolic resin; (C) at least one fluoroacid; and (D) at least one compound containing metal cations, in which the metal in the metal cations is selected from the group consisting of Fe, Mg, Mn, Zn, Mo, Ca, Cu, W, Re, Bi, Nb, Ta, Tr and any combinations thereof; wherein the pH value of the composition is in the range of 1.3 to 3.0. The present invention also relates to a working composition obtained by diluting the acidic Cr-free aqueous composition with water, a process for treating a metal surface with the acidic Cr-free aqueous composition or the working composition, and a substrate containing a metal surface treated by the process.

Inventors

  • NIU, MENGQI
  • ZHU, Yakun

Assignees

  • HENKEL AG & CO. KGAA
  • HENKEL ADHESIVE TECHNOLOGIES (SHANGHAI) CO., LTD.

Dates

Publication Date
20260507
Application Date
20241031

Claims (17)

  1. An acidic Cr-free aqueous composition for treating a metal surface, comprising: (A) at least one organosilane having at least one hydrolysable substituent and one or three non-hydrolysable substituents; (B) at least one organic polymer based on phenolic resin; (C) at least one fluoroacid; and (D) at least one compound containing metal cations, in which the metal in the metal cations is selected from the group consisting of Fe, Mg, Mn, Zn, Mo, Ca, Cu, W, Re, Bi, Nb, Ta, Tr and any combinations thereof; wherein the pH value of the composition is in the range of 1.3 to 3.0.
  2. The acidic Cr-free aqueous composition for treating a metal surface according to claim 1, wherein the component (B) is based on polyamide modified phenolic resin, epoxy modified phenolic resin and/or polyethylene modified phenolic resin.
  3. The acidic Cr-free aqueous composition for treating a metal surface according to claim 1 or 2, wherein the component (A) contains at least one compound according to the following general formula (I) : [H 2 N- ( <CH 2 > a NH) b (CH 2 ) c ] d -Si-X (4-d) (I) wherein X is each independently from each other selected from the group consisting of alkoxy groups having no more than 3 carbon atoms, preferably no more than 2 carbon atoms, and more preferably 1 carbon atom; a and c are each independently from another integers in a range of from 1 to 3; preferably, a is 2 and c is 3; b is an integer in a range of from 0 to 6, preferably in a range of from 0 to 3, and more preferably is 1; and d is an integer in a range of from 1 to 3, and preferably is 1.
  4. The acidic Cr-free aqueous composition for treating a metal surface according to claim 3, wherein the component (A) further contains at least one compound according to the following general formula (II) : wherein Y is each independently from each other selected from the group consisting of alkoxy groups having no more than 3 carbon atoms and preferably no more than 2 carbon atoms, and alkyl groups having no more than 3 carbon atoms and preferably no more than 2 carbon atoms; m is independently from each other an integer in a range of from 1 to 3, and preferably is 1; n is independently from each other an integer in a range of from 2 to 6, and preferably is 3; and p is an integer in a range of from 1 to 3, and preferably is 1.
  5. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 4, wherein the component (C) contains at least one coordination anion of element B, Zr, Ti, Hf, Al and/or Si, preferably at least one oxyfluoronic anion or fluoronic anion of element B, Zr, Ti, Hf, Al and/or Si, and more preferably at least one fluoronic anion of element Zr and/or Ti; and further preferably, the component (C) contains H 2 TiF 6 and/or H 2 ZrF 6 .
  6. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 5, wherein in the component (D) , the metal in the metal cations is selected from the group consisting of Mg, Zn, Fe, Mo, Mn and any combinations thereof; preferably, the metal in the metal cations is selected from the group consisting of Mg, Zn, Fe and any combinations thereof; and more preferably, the metal in the metal cations is the combination of Mg, Zn and Fe.
  7. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 6, which further comprises (E) at least one metal chelating stabilizer and/or (F) at least one metal surface dispersion wetting agent, and preferably both (E) at least one metal chelating stabilizer and (F) at least one metal surface dispersion wetting agent; wherein preferably, the component (E) is selected from the group consisting of phosphonic acids, aminosalicylic acid, ascorbic acid, aspartic acid, benzoic acid, citric acid, dicyanic acid, dihydroxybenzoic acid, ethylenetetraacetic acid, gluconic acid, glutamic acid, glycolic acid, hydroxyethyldiphosphonic acid, hydroxyglutamic acid, iminodisucinic acid, aspergillic acid, lactic acid, malonic acid, nitrobenzenesulfonic acid, nitrosalicylic acid, oxalic acid and polypropylene acid, polyaspartic acid, salicylic acid, tartaric acid and salts of said acids, and more preferably, the component (E) is etidronic acid; and/or preferably, the component (F) is selected from the group consisting of a cationic surfactant, a non-ionic surfactant, a polyether-modified polysiloxane compound, an acetylenediol compound and any combinations thereof, more preferably, the component (F) is selected from the group consisting of ethylene oxide admixtures, a polyether-modified polysiloxane compound, non-ionic fluorocarbon polymer compounds and any combinations thereof, and most preferably, the component (F) is a polyether-modified polysiloxane compound.
  8. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 7, wherein the pH value of the composition is in the range of 1.4 to 2.8, preferably in the range of 1.5 to 2.5, and more preferably in the range of 1.6 to 2.4.
  9. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 8, wherein the amount of the component (A) is no more than 15%by weight, preferably is in the range of from 0.1%to 10%by weight, and more preferably is in the range of from 3%to 8%by weight, based on the total amount of the composition.
  10. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 9, wherein the weight ratio of the component (A) to the component (B) is in the range of from 1: 1 to 1: 10, preferably in the range of from 1: 1.5 to 1: 6, and more preferably in the range of from 1: 2 to 1: 5.
  11. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 10, wherein the weight ratio of the component (A) to the component (C) is in the range of from 10: 1 to 1: 10, preferably in the range of from 5: 1 to 1: 5, more preferably in the range of from 2: 1 to 1: 3, and most preferably in the range of from 1.5: 1 to 1: 2.
  12. The acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 11, wherein the weight ratio of the component (A) to the component (D) is in the range of from 10: 1 to 1: 10, preferably in the range of from 5: 1 to 1: 5, and more preferably in the range of from 3: 1 to 1: 2.
  13. A working composition obtained by diluting the acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 12 with water, wherein the content of the acidic Cr-free aqueous composition is in the range of from 1 to 20%by weight, and preferably in the range of from 1.5 to 10%by weight, based on the total weight of the working composition.
  14. A process for treating a metal surface, comprising the following steps: (i) optionally, cleaning, degreasing and then rinsing the metal surface, (ii) contacting the metal surface with the acidic Cr-free aqueous composition for treating a metal surface according to any one of claims 1 to 12 or the working composition according to claim 13, and (iii) optionally, rinsing and/or drying the metal surface; wherein preferably, the process further comprises treating the metal surface with a primer and/or a topcoat.
  15. The process according to claim 14, wherein the step (ii) is carried out by immersion, spraying, and/or roller coating.
  16. The process according to claim 14 or 15, comprising the steps of treating the metal surface with a primer and a topcoat.
  17. A substrate containing a metal surface treated by the process according to any one of claim 14 to 16, which is preferably selected from hot galvanized sheet, aluminum zinc sheet, zinc-aluminum-magnesium sheet and any combinations thereof.

Description

Acidic Cr-free aqueous composition and process for treating a metal surface Technical field The present invention relates to an acidic Cr-free aqueous composition for treating a metal surface, a working composition obtained by diluting the acidic Cr-free aqueous composition with water, a process for treating a metal surface with the acidic Cr-free aqueous composition or the working composition, and a substrate containing a metal surface treated by the process. Background of the invention Currently, metal substrates used in the market mainly include hot dipped galvanized plate, galvalume (Al-Zn) , and ZAM (Zn-Al-Mg) with different Al contents, which are widely used in automotive, architectures (such as roof and corrugated plating) and household appliances (such as refrigerator and washing machine) . In recent years, most of commercially available products for treating the metal surface are focused on Cr3+/Cr6+, but the Cr3+/Cr6+ technology possesses toxicological and ecological risks. Thus, Cr-free aqueous compositions for treating a metal surface have been developed. However, Cr-free aqueous composition for treating a metal surface in the prior art cannot both have acceptable solution stability and wetting dispersion, and provide a coating on a metal surface having excellent T-bending force for the metal surface and the coating before and after ageing, good anti-corrosion performance, good acid resistance, and good alkaline resistance. In view of the above, it would be desirable to provide a Cr-free aqueous composition for treating a metal surface, which has acceptable solution stability and wetting dispersion, and provides a coating on a metal surface having excellent T-bending force for the metal surface and the coating before and after ageing, good anti-corrosion performance, good acid resistance, and good alkaline resistance. Summary of the invention The present invention provides an acidic Cr-free aqueous composition for treating a metal surface, comprising: (A) at least one organosilane having at least one hydrolysable substituent and one or three non-hydrolysable substituents; (B) at least one organic polymer based on phenolic resin; (C) at least one fluoroacid; and (D) at least one compound containing metal cations, in which the metal in the metal cations is selected from the group consisting of Fe, Mg, Mn, Zn, Mo, Ca, Cu, W, Re, Bi, Nb, Ta, Tr and any combinations thereof; wherein the pH value of the composition is in the range of 1.3 to 3.0. The present invention also provides a working composition obtained by diluting the acidic Cr-free aqueous composition for treating a metal surface according to the present invention with water, wherein the content of the acidic Cr-free aqueous composition is in the range of from 1 to 20%by weight, based on the total weight of the working composition. Moreover, the present invention provides a process for treating a metal surface, comprising the following steps: (i) optionally, cleaning, degreasing and then rinsing the metal surface, (ii) contacting the metal surface with the acidic Cr-free aqueous composition for treating a metal surface according to the present invention or the working composition according to the present invention, and (iii) optionally, rinsing and/or drying the metal surface. Furthermore, the present invention provides a substrate containing a metal surface treated by the process according to the present invention. All of the acidic Cr-free aqueous composition, working composition and process for treating a metal surface and the substrate according to the present invention are based on the following surprising discoveries of the inventors: the acidic Cr-free aqueous composition according to the present invention, especially the specific combination of components (A) to (D) and the pH value of the composition according to the present invention, has acceptable solution stability and wetting dispersion; and at the same time, the coating on the metal surface obtained with the acidic Cr-free aqueous composition according to the present invention has excellent T-bending force for the metal surface and the coating before and after ageing, good anti-corrosion performance, good acid resistance, and good alkaline resistance. Detailed description of the invention It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention. Each aspect so described may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or  advantageous may be combined with any other feature or features indicated as being preferred or advantageous. Unless specified otherwise, as used herein, the terms “a” , “an” and “the” include both singular and plural referents. As used herein, the term “at least one” means one or more, i.e., 1, 2, 3,