Solution and process for the pre-treatment of copper surfaces using an N-alkoxylated adhesion-promoting compound

1. A solution, comprising:

a) hydrogen peroxide;

b) an acid;

c) a nitrogen-containing, five-membered, heterocyclic compound; and

d) a lactam or a polyamide, which is connected at one or more of its nitrogen atoms with at least one residue of formula (I):

wherein:

n is an integer from 1 to 100;

R 1 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms;

R 2 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms; and

each R 1 and R 2 in a —(CHR 1 —CHR 2 —O)— moiety is selected independently of each R 1 and R 2 in another —(CHR 1 —CHR 2 —O)— moiety;

with the proviso that the compound of c) is not connected at any of its nitrogen atoms with a residue of formula (I).

2. The solution of claim 1 , wherein the compound of d) is a lactam of formula (II);

wherein:

n is an integer from 1 to 100;

R 1 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms;

R 2 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms;

each R 1 and R 2 in a —(CHR 1 —CHR 2 —O)— moiety is selected independently of each R 1 and R 2 in another —(CHR 1 —CHR 2 —O)— moiety; and

R 3 is a hydrocarbon residue with 1 to 20 carbon atoms.

3. The solution of claim 1 , wherein the compound of d) is a polyamide of formula (III):

wherein:

n is an integer from 1 to 100;

R 1 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms;

R 2 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms;

each R 1 and R 2 in a —(CHR 1 —CHR 2 —O)— moiety is selected independently of each R 1 and R 2 in another —(CHR 1 —CHR 2 —O)— moiety;

R 3 is a hydrocarbon residue with 1 to 20 carbon atoms, each R 3 in a —(N—R 3 —CO)— moiety is selected independently of each R 3 in another —(N—R 3 —CO)— moiety; and

each n in a —(CHR 1 —CHR 2 —O) n — moiety or chain is selected independently of each n in another —(CHR 1 —CHR 2 —O) n — moiety or chain.

4. The solution of claim 2 , wherein R 3 is an alkylene residue with the formula —(CH 2 ) y —, and wherein y is an integer from 2 to 12.

5. The solution of claim 1 , wherein the solution comprises a sulphur, selenium or tellurium-containing adhesion-promoting compound, said compound being a sulphinic acid, selenic acid, telluric acid, heterocyclic compound that comprises at least one sulphur, selenium and/or tellurium atom in the heterocycle, sulphonium salt, selenonium salt or telluronium salt, wherein the sulphonium salt, selenonium salt or telluronium salt has a general formula (VIII);

wherein:

A is S, Se or Te;

R 9 , R 10 and R 11 are independently alkyl, substituted alkyl, alkenyl, phenyl, substituted phenyl, benzyl, cycloalkyl, or substituted cycloalkyl; and

Z − is an anion of an inorganic or organic acid or hydroxide;

with the proviso that the acid of b) is not identical to the sulphinic, selenic or telluric acids selected for the sulphur, selenium or tellurium containing adhesion-promoting compound, and that the compound of c) contains no sulphur atom, selenium atom or tellurium atom in the heterocycle.

6. A method for pre-treating a copper surface for the subsequent formation of a firmly adhesive bond between the copper surface and a plastic material substrate, the method comprising contacting the copper surface with a solution comprising:

a) hydrogen peroxide;

b) an acid;

c) a nitrogen-containing, five-membered, heterocyclic compound; and

d) a lactam or a polyamide, which is connected at one or more of its nitrogen atoms with at least one residue of formula (I)

wherein

n is an integer from 1 to 100;

R 1 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms;

R 2 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms; and

each R 1 and R 2 in a —(CHR 1 —CHR 2 —O)— moiety is selected independently of each R 1 and R 2 in another —(CHR 1 —CHR 2 —O)— moiety;

with the proviso that the compound of c) is not connected at any of its nitrogen atoms with a residue of formula (I).

7. The method of claim 6 , wherein the copper surface is brought into contact with the solution.

8. A method of pre-treating a printed circuit board inner layer which has a copper layer, the method comprising contacting the printed circuit inner layer or a synthetic resin layer with the solution of claim 1 , and forming a firmly adhesive bond between the printed circuit inner layer and the synthetic resin layer.

9. The method of claim 8 , wherein the solution comprises a lactam or a polyamide, which is connected at one or more of its nitrogen atoms with at least one residue of formula (I):

wherein:

n is an integer from 1 to 100;

R 1 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms;

R 2 is hydrogen or a hydrocarbon residue with 1 to 6 carbon atoms; and

each R 1 and R 2 in a —(CHR 1 —CHR 2 —O)— moiety is selected independently of each R 1 and R 2 in another —(CHR 1 —CHR 2 —O)— moiety.