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CN-122029245-A - Use of a composition for improving adhesive bonding of surfaces and method for bonding surfaces

CN122029245ACN 122029245 ACN122029245 ACN 122029245ACN-122029245-A

Abstract

The invention relates to the use of a composition comprising a polymer P obtained by free radical copolymerization of (i) acrylic acid, (ii) optionally methacrylic acid, and (iii) at least one compound which is an ethylenically unsaturated polycarboxylic acid, for improving the adhesion between a metal surface (S1) and another surface (S2) by means of an adhesive layer, in particular in order to impart the adhesion failure resistance of the resulting adhesion.

Inventors

  • M-P. Labb
  • J.R. La Xie
  • O. Beck
  • G. Gordy
  • V. Divery

Assignees

  • 法国特种经营公司

Dates

Publication Date
20260512
Application Date
20241002
Priority Date
20231003

Claims (15)

  1. 1. Use of a composition comprising at least one polymer P for improving the adhesion between a metal surface (S1) and another surface (S2) by means of an adhesive layer, the at least one polymer P is obtained by free-radical copolymerization of a mixture comprising (Iv) Acrylic acid; (v) Optionally methacrylic acid, and (Vi) At least one compound having the formula I: (I) Wherein: -R and R 'are selected from H or methyl, provided that at least one of R or R' is H, preferably both are H; -R 1 and R 2 are independently of each other H, or the compound of formula (I) is in the form of a salt, wherein R 1 and/or R 2 are selected from the group consisting of alkali metals, alkaline earth metals and quaternary amines + NR 3 4 , wherein R 3 are independently of each other H or methyl or ethyl; -n is an integer ranging from 1 to 4; -m is an integer ranging from 0 to 4; -Ra, rb and Rc are independently from each other selected from H, -COOR 4 groups, aryl which may bear a sulfonic acid or sulfonate group or C 1 -C 4 linear alkyl which may bear a-COOR 4 group, wherein R 4 has the same definition as one of R 1 and R 2 , preferably H, with the proviso that when Ra, rb and/or Rc are aryl which may bear a sulfonic acid or sulfonate group or C 1 -C 4 linear alkyl which may bear a-COOR 4 group, then at least one of Ra, rb or Rc is H, preferably at least two of Ra, rb or Rc are H.
  2. 2. Use according to claim 1 for imparting anti-adhesive failure resistance to the bond and/or for further imparting corrosion atmosphere resistance and moisture atmosphere resistance to the bond.
  3. 3. Use according to claim 1 or 2, wherein the composition is used as a surface treatment of all or part of the metal surface (S1) and optionally all or part of the surface (S2) and/or as an additive in the adhesive layer.
  4. 4. Use according to any one of claims 1 to 3, wherein the polymer P is obtained by radical copolymerization of a mixture consisting essentially of: (i) Acrylic acid; (ii) Optionally methacrylic acid, and (Iii) At least one compound having formula I.
  5. 5. Use according to any one of claims 1 to 4, wherein the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio based on the total amount of acrylic acid, methacrylic acid and compounds having formula I: Acrylic acid 5% to 95%, notably 10% to 90%, preferably 30% to 85% Methacrylic acid from 0% to 50%, preferably from 0% to 40%, more preferably from 0% to 20% 1% To 90%, for example 5% to 50%, notably 8% to 45%, of a compound of formula I.
  6. 6. Use according to any one of claims 1 to 5, wherein the composition further comprises 10 to 75% by weight, preferably 25 to 50% by weight, of a compound of formula I, based on the total weight of the composition.
  7. 7. Use according to any one of claims 1 to 6, wherein the compound of formula I is selected from the group consisting of itaconic acid, α -methyleneglutaric acid, but-3-en-1, 2, 3-tricarboxylic acid, hex-5-en-1, 3, 5-tricarboxylic acid, salts thereof and mixtures thereof.
  8. 8. Use according to any one of claims 1 to 7, wherein the metal surface (S1) is a surface comprising a metal selected from aluminium, steel, zinc, magnesium, titanium, copper and alloys thereof, or cobalt-nickel alloys, preferably a surface of aluminium or an aluminium alloy.
  9. 9. A method for bonding a metal surface (S1) to another surface (S2), the method comprising: -treating all or part of said metal surface (S1) with a composition as defined in any one of claims 1 to 7, and -Optionally treating all or part of said second surface (S2) with a composition as defined in any one of claims 1 to 7, and -Bonding the two surfaces (S1) via an adhesive layer applied between the two surfaces (S2).
  10. 10. The method of claim 9, wherein the composition is: -a conversion composition, and/or -A solution or dispersion which is applied on the surface to be treated after application of the conversion coating on the surface.
  11. 11. A method for bonding a metal surface (S1) to another surface (S2), the method comprising bonding the two surfaces via an adhesive layer applied between the surface (S1) and the surface (S2), said adhesive layer comprising a composition as defined in any one of claims 1 to 7.
  12. 12. The method of claim 11, further comprising the step, prior to the step of bonding the surface S1 and the surface S2, of: -treating all or part of said metal surface (S1) with a composition as defined in any one of claims 1 to 7, and -Optionally treating all or part of the second surface (S2) with a composition as defined in any one of claims 1 to 7.
  13. 13. A coating or adhesive composition comprising a polymer P as defined in any of claims 1 to 7, including but not limited to inks and coatings, such as waterborne and powder coatings.
  14. 14. Use of the polymer P as defined in any of claims 1 to 7 as adhesion promoter in coatings, inks and paints (e.g. water-borne paints and powder paints), or as adhesion promoter imparting corrosion resistance in (post) conversion coatings, i.e. in any step carried out before painting.
  15. 15. A method for bonding a coating or varnish to a metal surface (S1), the method comprising: -treating all or part of said metal surface (S1) with a composition comprising a polymer P as defined in any one of claims 1 to 7, and -Applying a coating or varnish to the surface (S1).

Description

Use of a composition for improving adhesive bonding of surfaces and method for bonding surfaces The present application claims priority from the application filed on 10/3/2023 in europe under No. 23306691.9, the entire contents of which are incorporated herein by reference for all purposes. The present invention relates to the field of adhesive bonding of metal surfaces/parts. The invention more particularly relates to the use of a composition comprising a specific polymer for improving the adhesion between a metal surface (S1) and another surface (S2) by means of an adhesive layer, in particular in order to impart adhesion failure resistance to the resulting adhesion. Background In order to provide enhanced adhesion of the adhesive on metal surfaces, in particular on aluminum or steel, several methods have been proposed, including depositing an inorganic coating, in particular a so-called "conversion coating", on the metal surface. The term "conversion coating" is well known in the art and refers to a layer formed on a metal surface that is an advantageous replacement for native oxides on said surface (especially on aluminum) and that is obtained by controlled chemical formation of a film or layer on the metal surface by reaction with chemical elements of the metal surface such that at least some of the cations dissolved out of the metal material are deposited in the conversion coating. The conversion coating technology has evolved significantly over the last decades, hexavalent chromium (Cr-VI, such as CrO 3) has been widely used in the past (especially on aluminum) and its use has been increasingly limited due to its toxicity. Technologies such as zinc phosphate (Zn-P) have been dominant for low carbon steel, galvanized steel and multi-metal production lines containing less than 30% aluminium, and today face increasing challenges in that Zn-P conversion produces toxic waste/sludge containing toxic metals (Ni, mn, co, etc.) in addition to water and energy consumption being significantly higher than other conversion coating technologies, and its disposal is more and more expensive. The problems posed by both Cr-VI and Zn-P have led to the development of new technologies, trivalent chromium (Cr-III, such as chromium nitrate Cr (NO 3)3) and transition metal hexafluoroides, although Cr-III has not been categorized so far, it is affected by the negative image of chromium and its use has become more and more challenging. However, hexafluorocompounds are known to produce relatively smooth surfaces that can negatively impact paint adhesion, while other surface treatment techniques form entanglement of crystals protruding at the metal surface, thereby increasing surface area, improving coating adhesion by mechanical interlocking. In order to improve the adhesion on coatings, such as conversion coatings, it is known to include additives, in particular organic polymers. In this connection, it has been described, for example, to use copolymers made of acrylic acid and vinylphosphonic acid. For more details on this, reference may be made in particular to GB 233982 and US 6,020,030. A typical additive is Addibond TM 021 available from SolvAY, inc., which has been widely described for this application. However, the P-based component is under increasingly stringent scrutiny. In the last few decades, several cities in china and western countries have passed the act of limiting the concentration of phosphorus in wastewater discharged into the environment. Against this background, there is a need for a polymer free of P that exhibits similar properties as P-based polymers. Disclosure of Invention It is an object of the present invention to provide a new performance solution for improving the adhesion between a metal surface and another surface, preferably also a metal surface, by means of an adhesive layer, such that this new solution, although free of phosphorus, provides similar performance as the widely accepted P-based solution. For this purpose, the invention proposes the use of a specific polymer, optionally (but not necessarily) together with the formation of the conversion coating (i.e. before, during or after the formation of the conversion coating), to treat a metal surface, preferably a portion of the surfaces of two solid parts (in particular metal parts) to be bonded together by adhesive bonding, before bonding it to another surface via an adhesive composition or layer (so-called "adhesive bonding"). It has been found that the use of a composition comprising this specific polymer as a coating pretreatment for a metal surface or as an additive in an adhesive composition to be applied between the metal surface and another surface provides a particularly good adhesion between the two surfaces/parts. The compositions comprising specific polymers used according to the invention allow anti-adhesive failure. Within the scope of the present invention, the inventors have now observed that the adhesion between the adhesi