Metallization inhibitors for plastisol coated plating tools
View Patent ↗The plastisol coated plating tools are used to secure polymer containing substrates in electroless plating baths during electroless plating of the polymers. To prevent metallization of the plastisol coated plating tools during electroless metallization, compositions of sulfur compounds are applied to the plastisol. After metallization the plastisol coated plating tools may be re-used without the need to strip the unwanted metal from the tools.
1. A method comprising:
a) providing a plating tool comprising plastisol;
b) applying a composition comprising one or more surfactants having an HLB of 5 to 15 and a sulfur compound containing a sulfur atom in an oxidation state equal to −1 or −2 or a mixture of sulfur compounds having sulfur atoms with oxidation states of −1 and −2 to the plastisol;
c) fastening a substrate comprising one or more polymers to the plating tool;
d) etching the one or more polymers with a chromium (VI) free etch composition or a low chromic acid etch composition;
e) applying a catalyst to the one or more polymers; and
f) electroless plating a metal on the one or more polymers.
2. The method of claim 1 , wherein the sulfur compound containing the sulfur atom in an oxidation state equal to −1 is chosen from one or more disulfides.
3. The method of claim 2 , wherein the one or more disulfides are chosen from di-n-allyl-disulfide, di-n-hexyl-disulfide, di-isopropyl-disulfide, isopentyl disulfide, tert-heptyl disulfide, di-octyl-disulfide, di-undecyl disulfide, di-dodecyl disulfide, di-hexadecyl disulfide, octadecyl disulfide, bis(16-hydroxyhexadecyl) disulfide, bis(11-cyanoundecyl) disulfide, bis-(3-sulfopropyl)-disulfide (SPS), diphenyl-disulfide, dibenzyl disulfide, benzyl methyl disulfide, PEG-propionate disulfide, furfuryl disulfide, thiram, and disulfiram.
4. The method of claim 1 , wherein the sulfur compound containing the sulfur atom in an oxidation state equal to −2 is chosen from one or more of thiols, thioethers, thiourethanes, dithiocarbamtes, thioester, dithioesters, thioureas, thioamides, and aromatic heterocyclic sulfur containing compounds.
5. The method of claim 4 , wherein the sulfur compound containing the sulfur atom in an oxidation state equal to −2 is chosen from one or more thiols.
6. The method of claim 5 , wherein the one or more thiols comprise hydrophobic segments of 4 to 36 carbon atoms.
7. The method of claim 6 , wherein the one or more thiols comprise hydrophobic segments of 8 to 18 carbon atoms.
8. The method of claim 1 , wherein the sulfur compound containing the sulfur atom in an oxidation state equal to −1 or −2 or a mixture of sulfur compounds having sulfur atoms with oxidation states of −1 and −2 ranges from 0.1 g/L to 200 g/L.
9. The method of claim 1 , wherein the composition further comprises one or more organic solvents.
10. The method of claim 1 , wherein the chromium (VI) free etch composition is chosen from cerium (IV)/silver (I) acid etch, Mn (VII) etch and Mn(II)/Mn(III) acidic etch.
11. The method of claim 1 , wherein the catalyst comprises a colloidal catalyst or ionic catalyst.
12. The method of claim 1 , wherein the plastisol comprises polyvinyl chloride, dibutyl phthalates, mixed benzyl-butyl phthalates, di-(2-ethylhexyl) phthalates, dihexyl phthalates, diisononyl phthalates, styrene-acrylonitrile, acrylonitrile-butadiene-styrene, synthetic-butyl rubber, chlorinated polyethylene or mixtures thereof.