Selective deposition of metal on plastic substrates
View Patent ↗The present invention relates to a method of selectively plating a plastic article comprising a first polymer resin portion and a second polymer resin portion, wherein said first polymer resin portion is not rendered plateable by sulfonation and said second polymer resin portion is rendered plateable by sulfonation. The method comprises the steps of sulfonating the plastic article, activating the sulfonated plastic article to accept plating thereon, and plating the sulfonated and activated article in an electroless plating bath. The plastic article is selectively plated such that the first polymer resin portion does not have plating thereon and the second polymer resin portion is electrolessly plated.
1. A method of selectively plating a plastic article comprising a first polymer resin portion and a second polymer resin portion, wherein said first polymer resin portion is not rendered plateable by sulfonation and said second polymer resin portion is rendered plateable by sulfonation, the method comprising the steps of:
a) contacting the first polymer resin portion and the second polymer resin portion of the plastic article with a sulfonating agent, wherein the second polymer resin portion is rendered plateable by sulfonation;
b) contacting the sulfonated plastic article with an activating agent comprising ionic palladium followed by an ionic palladium reducer so as to accept electroless plating thereon;
plating the sulfonated and activated plastic article in an electroless plating bath;
wherein the first polymer resin portion comprises a catalytic poison compound;
wherein the first polymer resin portion comprises a different polymer from the second polymer resin portion; and
whereby the plastic article is selectively plated such that the first polymer resin portion does not have plating thereon and the second polymer resin portion is electrolessly plated.
2. The method according to claim 1 , wherein the first polymer resin portion comprises polycarbonate resin.
3. The method according to claim 2 , wherein the second polymer resin portion comprises acrylonitrile-butadiene-styrene (ABS) resin or ABS/polycarbonate resin.
4. The method according to claim 1 , wherein the electroless plating bath comprises electroless copper or electroless nickel.
5. The method according to claim 1 , wherein the plastic article is formed by double-shot molding in which the first polymer resin portion and the second polymer resin portion are forced under pressure into a closed mold or molds and the materials solidify within the mold cavity.
6. The method according to claim 1 , wherein the plastic article is selectively plated without using a chromic acid/sulfuric acid etching step.
7. The method according to claim 1 , wherein the sulfonation agent comprises fuming sulfuric acid or vapor phase sulfur trioxide.
8. The method according to claim 7 , wherein the sulfonating agent comprises vapor phase sulfur trioxide.