Process for applying a metal coating to a non-conductive substrate

1. A process for applying a metal coating to a non-conductive substrate comprising the steps of

(a) contacting the substrate with an activator comprising a noble metal/group IVA metal sol to obtain a treated substrate,

(b) contacting said treated substrate with a composition comprising a solution of:

(i) a Cu(II), Ag, Au or Ni soluble metal salt or mixtures thereof,

(ii) 0.05 to 5 mol/l of a group IA metal hydroxide and

(iii) a complexing agent for an ion of the metal of said metal salt, characterised in that iminosuccinic acid or a derivative thereof is used as said complexing agent.

2. The process according to claim 1 wherein the composition further comprises a second complexing agent in addition to the iminosuccinic acid or its derivative.

3. The process according to claim 1 wherein the complexing agent is used in an amount of 0.005 to 1 mol/l.

4. The process according to claim 2 wherein the second complexing agent is used in an amount of 0.05 to 1.0 mol/l.

5. The process according to claim 4 wherein the second complexing agent is used in an amount of 0.2 to 0.5 mol/l.

6. The process according to claim 5 wherein the second complexing agent is selected from the group consisting of gluconic acid, lactic acid, acetic acid and tartaric acid and salts thereof.

7. The process of claim 1 wherein the composition is obtained from a kit-of-parts, said kit-of-parts comprising composition (A) and (B) wherein composition (A) comprises:

(A1) said iminosuccinic acid or a derivative thereof,

(A2) said soluble metal salt

and wherein composition (B) comprises:

(B1) said group IA metal hydroxide.

8. A composition for use in a process for applying a metal coating to a non-conductive substrate comprising:

(i) a Cu(II), Ag, Au or Ni soluble metal salt or mixtures thereof,

(ii) iminosuccinic acid or a derivative thereof, and

(iii) 0.05 to 5 mol/l of a group IA metal hydroxide.

9. The composition according to claim 8 wherein the iminosuccinic acid derivative has the formula (I):

wherein R 1 is selected from the group consisting of H, Na, K, NH 4 , Ca, Mg, Li and Fe,

R 2 is selected from the group consisting of

—CH 2 —COOR 1 , —CH 2 —CH 2 —COOR 1 , —CH 2 —CH 2 —OH, —CH 2 —CHOH—CH 3 and —CH 2 —CHOH—CH 2 OH, and

R 3 is selected from the group consisting of H, —CH 2 —COOR 1 , —CH 2 —CH 2 —COOR 1 , —CH 2 —CH 2 —OH, —CH 2 —CHOH—CH 3 and —CH 2 —CHOH—CH 2 OH.

10. The composition according to claim 8 further comprising a second complexing agent selected from the group consisting of acetate, acetylacetone, citric acid, 1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic acid, dimethylglyoxime (50% dioxane), 2,2′-dipyridyl, ethanolamine, ethylenediamine, ethylenediamine N,N,N′,N′-tetraacetic acid, glycine, N′-(2-hydroxyethyl)ethylenediamine-N,N,N′-triacetic acid, 8-hydroxy-2-methylquinoline (50% dioxane), 8-hydroxyquinoline-5-sulfonic acid, lactic acid, nitrilotriacetic acid, 1-nitroso-2-naphthol (75% dioxane), oxalate, 1,10-phenanthroline, phthalic acid, piperidine, propylene-1,2-diamine, pyridine, pyridine-2,6-dicarboxylic acid, 1-(2-pyridylazo)-2-naphthol (PAN), 4-(2-pyridylazo)resorcinal (PAR), pyrocatechol-3,5-disulfonate, 8-quinolinol, salicyclic acid, succinic acid, 5-sulfosalicyclic acid, tartaric acid, thioglycolic acid, thiourea, triethanolamine, triethylenetetramine (trien), and 1,1,1-trifluoro-3-2′-thenoylacetone (TTA) in an amount of 0.05 to 1.0 mol/l.

11. The composition according to claim 10 comprising the second complexing agent in an amount of 0.2 to 0.5 mol/l.

12. The composition according to claim 11 wherein the second complexing agent is selected from the group consisting of gluconic acid, lactic acid, acetic acid and tartaric acid and salts thereof.