Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/38—Electroplating: Baths therefor from solutions of copper
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/10—Electroplating with more than one layer of the same or of different metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/627—Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance

Definitions

• the present invention relates to a method for deposition of matte copper deposits in the field of decorative coatings.
• Matte copper coatings in the field of decorative coatings are required as a surface finish for e.g. sanitary equipment.
• Another application of matte copper coatings is to replace matte nickel layers (“satin nickel”) as an intermediate layer in decorative multilayer coating systems which becomes more demanding due to the toxicity of nickel.
• a homogeneous matte appearance is required for decorative metal layers.
• the homogeneity of the matte appearance can easily be achieved on substrates which have no complex shape because the current density distribution during electroplating of matte copper layers is within a narrow range. However, in cases where the substrate to be coated has a complex shape, the current density during electroplating is within a wide range.
• Typical substrates having a complex shape which are to be coated with a matte copper coating are for example shower heads and automotive interior parts.
• matte copper layers Another requirement for matte copper layers is that their matte level should be adjustable in order to be able to manufacture copper layers having different matte levels.
• Plating bath compositions comprising at least one polyglycerine compound for producing matte copper layers during manufacture of printed circuit boards are disclosed in US 2004/0020783 A1. It is neither possible to obtain a homogeneously matte copper deposit on a substrate having a complex shape nor to adjust the matte level of such a copper deposit when using the electrolyte disclosed therein.
• the copper coatings obtained by the method according to the present invention have a homogeneous matte appearance on substrates having a complex shape. Furthermore, the matte appearance of the copper coating can be adjusted during deposition of the individual copper layers.
• the method for deposition of a matte copper coating comprises deposition of two individual copper layers onto a substrate from two individual copper electrolytes which are herein denoted first electrolyte from which the first copper layer is deposited and second electrolyte from which the second copper layer is deposited onto the first copper layer.
• the first electrolyte comprises a source of copper ions, at least one acid and at least one polyether compound.
• the first electrolyte does not contain an organic compound comprising divalent sulfur, e.g., sulfides, disulfides, thiols, and derivatives thereof.
• Copper ions are added to the first electrolyte in the form of a water-soluble copper salt or an aqueous solution thereof.
• the source of copper ions is selected from copper sulfate and copper methane sulfonate.
• the concentration of copper ions in the first electrolyte preferably ranges from 15 to 75 g/l, more preferably from 40 to 60 g/l.
• the at least one acid in the first electrolyte is selected from the group comprising sulfuric acid, fluoroboric acid and methane sulfonic acid.
• the concentration of the at least one acid in the first electrolyte preferably ranges from 20 to 400 g/l and more preferably from 40 to 300 g/l.
• sulfuric acid is used as the acid, it is preferably added in form of a 50 to 96 wt.-% solution. More preferably, sulphuric acid is added to the first electrolyte as a 50 wt.-% aqueous solution of sulfuric acid.
• the at least one polyether compound in the first electrolyte is selected from the group consisting of polyalkylene ethers and polyglycerine compounds.
• Suitable polyalkylene ethers are selected from the group consisting of polyethylene glycol, polypropylene glycol, stearylalcoholpolyglycolether, nonylphenolpolyglycolether, octanolpolyalkylenglcolether, octanediol-bis(polyalkylenglycolether), poly(ethylenglycol-ran-propylenglycol), poly(ethylenglycol)-block-poly(propylenglycol)-block-poly(ethylenglycol) and poly-(propylenglycol)-block-poly(ethylenglycol)-block-poly(propylenglycol).
• Suitable polyglycerine compounds are selected from the group consisting of poly(1,2,3-propantriol), poly(2,3-epoxy-1-propanol) and derivatives thereof which are represented by formulae (1), (2) and (3):
• n is an integer from 1 to 80, preferably from 2 to 30;
• R 6 , R 7 and R 8 are identical or different and are selected from the group consisting of hydrogen, alkyl, acyl, phenyl and benzyl, wherein alkyl preferably is linear or branched C 1 to C 18 alkyl and acyl preferably is R 10 —CO, wherein R 10 is linear or branched C 1 to C 18 alkyl, phenyl or benzyl; alkyl phenyl and benzyl in formula (1) may be substituted;
• R 6 , R 7 , R 8 and R 9 are identical or different and are selected from the group consisting of hydrogen, alkyl, acyl, phenyl and benzyl, wherein alkyl preferably is linear or branched C 1 to C 18 alkyl and acyl preferably is R 10 —CO, wherein R 10 is linear or branched C 1 to C 18 alkyl, phenyl or benzyl; alkyl phenyl and benzyl in formula (2) may be substituted;
• n is an integer from 1 to 80; preferably from 2 to 20; and wherein R 6 , R 7 are selected from the group consisting of hydrogen, alkyl, acyl, phenyl and benzyl, wherein alkyl preferably is linear or branched C 1 to C 18 alkyl and acyl preferably is R 10 —CO, wherein R 10 is linear or branched C 1 to C 18 alkyl, phenyl or benzyl; alkyl phenyl and benzyl in formula (3) may be substituted.
• Polyglycerine compounds are produced according to known methods. Indications on the conditions of production are disclosed in the following publications for example: Cosmet. Sci. Technol. Ser., glycerines, page 106 and U.S. Pat. No. 3,945,894. Further details on the syntheses of polyglycerine compounds according to formulae (1), (2) and (3) are disclosed in US 2004/0020783 A1.
• the at least one polyether compound in the first electrolyte is selected from compounds according to formulae (1), (2) and (3).
• the concentration of the at least one polyether compound or all polyether compounds together in case more than one polyether compound is added preferably ranges from 0.005 g/l to 20 g/l, more preferably from 0.01 g/l to 5 g/l.
• the temperature of the first electrolyte is preferably adjusted to a value in the range of from 30 to 60° C., more preferably from 40 to 50° C.
• the current density applied to the substrate during copper deposition from the first aqueous electrolyte preferably ranges from 0.5 to 5 A/dm 2 , more preferably from 1 to 3 A/dm 2 .
• the substrate is rinsed with water before depositing the second copper layer from the second electrolyte.
• Copper ions are added to the second electrolyte as a water-soluble copper salt or an aqueous solution thereof.
• the source of copper ions is selected from copper sulfate and copper methane sulfonate.
• the concentration of copper ions in the second electrolyte preferably ranges from 15 to 75 g/l, more preferably from 40 to 60 g/l.
• the at least one acid in the second electrolyte is selected from the group comprising sulfuric acid, fluoroboric acid and methane sulfonic acid.
• the concentration of the at least one acid in the second electrolyte preferably ranges from 20 to 400 g/l and more preferably from 40 to 300 g/l.
• sulfuric acid is used as the acid, it is added in form of a 50 to 96 wt.-% solution.
• sulfuric acid is added as a 50 wt.-% aqueous solution of sulfuric to the second electrolyte.
• the second electrolyte further comprises a first water-soluble sulfur-containing additive and a second water-soluble sulfur-containing additive.
• the first water-soluble sulfur-containing compound is an alkyl sulfonic acid derivative.
• the alkyl sulfonic acid derivative comprises divalent sulfur.
• the second water-soluble sulfur-containing compound is an aromatic sulfonic acid derivative.
• the aromatic sulfonic acid derivative comprises divalent sulfur.
• the first sulfur-containing additive is more preferably selected from the group consisting of compounds according to formulae (4) and (5):
• R 1 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, lithium, sodium, potassium and ammonium, more preferably R 1 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, sodium and potassium; n is an integer from 1 to 6, more preferably n is an integer from 2 to 4; R 2 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, lithium, sodium, potassium and ammonium, more preferably, R 2 is selected from the group consisting of hydrogen, sodium and potassium; R 3 is selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, lithium, sodium, potassium and ammonium, more preferably R 3 is selected from the group consisting of hydrogen, sodium, potassium and m is an integer from 1 to 6, more preferably m is an integer from 2 to 4.
• the concentration of the first sulfur-containing additive in the second electrolyte preferably ranges from 0.0001 to 0.05 g/l, more preferably from 0.0002 to 0.025 g/l.
• the second sulfur-containing additive in the second electrolyte is more preferably selected from the group consisting of compounds according to formulae (6) and (7):
• R 4 is selected from the group consisting of
• X is selected from the group consisting of
• y is an integer from 1 to 4 and M is selected from the group consisting of hydrogen, sodium, potassium and ammonium;
• R 5 is selected from the group consisting of hydrogen, SH and SO 3 M and M is selected from the group consisting of hydrogen, sodium, potassium and ammonium.
• the second sulfur-containing additive is selected from compounds according to formula (6).
• the concentration of the second sulfur-containing additive in the second electrolyte preferably ranges from 0.005 to 1 g/l, more preferably from 0.01 to 0.25 g/l.
• the second electrolyte further comprises one or more carrier additive selected from the group consisting of polyvinylalcohol, carboxymethylcellulose, polyethylene glycol, polypropylene glycol, stearic acid polyglycolester, alkoxylated naphtoles, oleic acid polyglycolester, stearylalcoholpolyglycolether, nonylphenolpolyglycolether, octanolpolyalkylenglycolether, octanediol-bis(polyalkylenglycolether), poly(ethylenglycol-ran-propylenglycol), poly(ethylenglycol)-block-poly(propylenglycol)-block-poly(ethylenglycol) and poly(propylenglycol)-block-poly(ethylenglycol)-block-poly(propylenglycol).
• carrier additive selected from the group consisting of polyvinylalco
• the concentration of the optional carrier additive in the second electrolyte preferably ranges from 0.005 g/l to 5 g/l, more preferably from 0.01 g/l to 3 g/l.
• the temperature of the second electrolyte is preferably adjusted to a value in the range of from 20 to 50° C., most preferably of from 25 to 30° C.
• the current density applied to the substrate during copper deposition from the second aqueous electrolytes preferably ranges from 0.5 to 5 A/dm 2 , more preferably from 1 to 3 A/dm 2 .
• the matte level of the copper surface may be tailored by adjusting the thicknesses of the first and second copper layer by simple experimentation. A more matte appearance may be achieved with a thinner second copper layer, whereas a less matte appearance may be achieved with a thicker second copper layer.
• ABS acrylonitrile-butadiene-styrol-copolymer
• brass substrates having a complex shape were used throughout all examples.
• ABS substrates were etched in chromic acid, activated with a palladium containing colloid and metallised by electroless plating of nickel from an acidic hypophosphite-based electrolyte prior to copper deposition.
• the brass substrates were degreased prior to deposition of copper.
• a homogenous, strongly matte copper surface was obtained which is too matte for decorative applications.
• the copper surface obtained has a homogenous technical gloss which is not desired for decorative applications.
• a first layer of copper was deposited onto ABS and brass substrates having a complex shape from the electrolyte used in example 2. Thereon, a second copper layer was deposited from the electrolyte used in example 1.
• a homogenous, strongly matte copper surface was obtained which is too matte for decorative applications.
• a first copper layer was deposited onto ABS and brass substrates having a complex shape from the electrolyte used in example 1.
• the second electrolyte did not contain a second sulfur-containing additive selected from compounds according to formulae (6) and (7).
• the resulting copper surface has a non-homogeneous matte appearance which is not acceptable for decorative applications.
• a first copper layer was deposited onto ABS and brass substrates having a complex shape from the electrolyte used in example 1.
• a second copper layer was deposited thereon from a second electrolyte comprising 80 g/l CuSO 4 .5H 2 O, 240 g/l sulfuric acid, and 80 mg/l of a sulfur-containing additive according to formula (6) with
• the second electrolyte did not contain a first sulfur-containing additive selected from compounds according to formulae (4) and (5).
• the copper surface obtained has a matte appearance with burnt areas (shady black appearance) which is not acceptable for decorative applications.
• the first copper layer was deposited onto the ABS and brass substrates from the electrolyte used in Example 1.
• the second copper layer was deposited thereon from the electrolyte used in Example 2.
• the copper surface obtained has a homogeneous matte appearance which is desired for decorative applications.
• the first copper layer was deposited from a first electrolyte comprising 80 g/l CuSO 4 .5H 2 O, 240 g/l sulfuric acid, and 1 g/l polyethylene glycol.
• the second copper layer was deposited thereon from the electrolyte used in Example 2.
• the copper surface obtained has a homogeneous matte appearance which is desired for decorative applications.
• Example 1 Example 2* Example 3* Example 4* Example 5* Example 6
• Example 7 First Containing none Containing Containing Containing Containing Containing Containing Containing electrolyte mix of additives with mix of mix of mix of polyethyleneglycol; polyglycines divalent sulfur polyglycines polyglycines No additive according to according to according to according to with divalent formula (1); formula (5) formula (1); formula (1); formula (1); sulfur No additive and (6) No additive No additive No additive with divalent with divalent with divalent sulfur sulfur sulfur sulfur sulfur sulfur sulfur Second none Containing Containing Containing Containing Containing Containing Containing electrolyte additives with mix of additive with additive with additives with additives with divalent sulfur polyglycines divalent sulfur divalent sulfur divalent sulfur according to according to according to according to according to formula (5) formula (1); formula (5); formula (6); formula formula (1); formula (5); formula (6); formula (1);

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• 2012
  • 2012-01-25 PL PL12152390T patent/PL2620529T3/pl unknown
  • 2012-01-25 ES ES12152390.6T patent/ES2478267T3/es active Active
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