Method for metallizing a non-metallic substrate and pre-treatment composition

Abstract

The present invention relates to a method for metallizing a non-metallic substrate, the method comprising the steps (A) to (C), wherein step (A) is a pre-treatment step for etching and step (C) the metallization step. In step (A) a pre-treatment composition is utilized comprising individual manganese (II), (III), and (IV) species. The present invention furthermore relates to a specific pre-treatment composition.

1 . A method for metallizing a non-metallic substrate, the method comprising the steps:
 (A) contacting the non-metallic substrate with a pre-treatment composition such that a pre-treated substrate is obtained,
 wherein the pre-treatment composition comprises: 
 (A-a) individual manganese (II), (III), and (IV) species, 
   (B) contacting the pre-treated substrate with an activation composition such that an activated substrate is obtained, and   (C) contacting the activated substrate with one or more than one metalizing composition such that a metalized substrate is obtained,   with the proviso that
 in the pre-treatment composition, the total concentration of manganese (IV) species is higher than the combined concentration of manganese (II) and (III) species, 
 an electrical current is applied to the pre-treatment composition such that manganese (II) species are oxidized to manganese (III) species, and 
 in step (A) contacting said substrate with manganese species is carried out in a single step. 
   
     
     
         2 . The method of  claim 1 , wherein in step (A) the pretreatment composition is substantially free of, permanganate ions. 
     
     
         3 . The method of  claim 1 , wherein in the pretreatment composition manganese (III) species disproportionate to manganese species comprising manganese (IV) species. 
     
     
         4 . The method of  claim 1 , wherein the electrical current has an anodic current density in a range from 0.1 A/dm 2  to 20 A/dm 2 . 
     
     
         5 . The method of  claim 1 , wherein during step (A) or prior to step (B) the pre-treated substrate is not contacted with a composition comprising a reducing agent capable to chemically reduce manganese dioxide. 
     
     
         6 . The method of  claim 1 , wherein during step (A) in the pre-treatment composition the total amount of all manganese species is more than 5.0 g/L, based on the total volume of the pre-treatment composition and the element manganese. 
     
     
         7 . The method of  claim 1 , wherein the pre-treatment composition additionally comprises
 (A-b) one, two or more than two acids.   
     
     
         8 . The method of  claim 7 , wherein the pre-treatment composition comprises at least a combination of sulfuric acid and phosphoric acid, wherein the phosphoric acid has a higher concentration than the sulfuric acid. 
     
     
         9 . The method of  claim 1 , wherein the pre-treatment composition has an absorbance of more than 1.0, referenced to a wavelength of 400 nm and a path length of 1 cm. 
     
     
         10 . The method of  claim 1 , wherein the pre-treatment composition additionally comprises
 (A-c) one or more than one species of additional transition metal ions different from manganese.   
     
     
         11 . The method of  claim 1 , wherein the pre-treatment composition has a density in a range from 1.50 g/cm 3  to 1.90 g/cm 3 , referenced to a temperature of 25° C. 
     
     
         12 . The method of  claim 1 , wherein step (C) comprises a contacting with at least one metalizing composition comprising nickel ions. 
     
     
         13 . The method of  claim 1 , wherein step (C) comprises step
 (C-1) contacting the activated substrate with a first metalizing composition for electroless plating to obtain a metalized substrate having a first nickel/nickel alloy metal layer, wherein the first metalizing composition comprises nickel ions and a reducing agent for nickel ions.   
     
     
         14 . The method of  claim 13 , wherein step (C) comprises after step (C-1) step
 (C-2) contacting the metalized substrate having the first nickel/nickel alloy metal layer with a second metalizing composition for electrolytic plating to obtain a metalized substrate with a second nickel/nickel alloy metal layer, wherein the second metalizing composition comprises nickel ions.   
     
     
         15 . A pre-treatment composition comprising
 (A-a) Mn(II) ions, Mn(III) ions, and colloidal manganese (IV) species,   (A-b) one, two or more than two acids,   (A-c) silver ions,   wherein the pre-treatment composition has
 a density in a range from 1.50 g/cm 3  to 1.90 g/cm 3 , referenced to a temperature of 25° C., and 
 an absorbance in a range from 1.1 to 2.1, referenced to a wavelength of 400 nm and a path length of 1 cm, 
   with the proviso that the pre-treatment composition
 is substantially free of methane sulfonic acid, salts thereof, and chloride ions, 
 is substantially free of permanganate ions. 
   
     
     
         16 . The method of  claim 1 , wherein in step (A) the pre-treatment composition comprises permanganate ions only up to a total concentration of 100 mg/L, based on the total volume of the pre-treatment composition. 
     
     
         17 . The method of  claim 1 , wherein during step (A) or prior to step (B) the pre-treated substrate is not contacted with a composition comprising any reducing agent. 
     
     
         18 . The method of  claim 1 , wherein step (C) comprises a contacting with at least two distinct metalizing compositions each comprising nickel ions. 
     
     
         19 . The method of  claim 13 , wherein step (C) comprises after step (C-1) step
 (C-2) contacting the metalized substrate having the first nickel/nickel alloy metal layer with a second metalizing composition for electrolytic plating to obtain a metalized substrate with a second nickel/nickel alloy metal layer, wherein the second metalizing composition comprises nickel ions- and is substantially free of a reducing agent for nickel ions.