Method of Improving the Solderability of a Printed Circuit Board

Abstract

A process for producing a coated article, which has (i) at least one electrically non-conductive base layer, (ii) at least one layer of copper and/or a copper alloy, and (iii) a layer which contains at least one electrically conductive polymer. The article is characterized in that the copper or copper alloy layer (ii) is positioned between the base layer (i) and the layer (iii) containing the conductive polymer.

1 . A method of improving the solderability of a printed circuit board:
 providing a printed circuit board comprising at least one electrically non-conductive base layer (i) and at least one layer (ii) comprising at least one of copper and a copper alloy; and   improving the solderability of the printed circuit board by applying a dispersion layer (iii) to the copper or copper alloy layer, which dispersion layer (iii) comprises a dispersion medium which is liquid at room temperature, and which dispersion medium comprises at least one intrinsically conductive polymer, and at least one complexing agent capable of complexing copper.   
   
   
       2 . The method according to  claim 1 , wherein the dispersion medium further comprises at least one electrically non-conductive polymer. 
   
   
       3 . The method according to  claim 1 , wherein the dispersion medium further comprises an additional component, which is selected from a group consisting of electrically non-conductive components, complexing agents, viscosity modifiers, flow aids, drying aids, gloss improvers, and flatting agents. 
   
   
       4 . The method according to  claim 1 , wherein the dispersion medium comprises at least one of water and an organic solvent miscible with water. 
   
   
       5 . The method according to  claim 1  further comprising applying a dispersion layer (iii) having a layer thickness of 10 nm to 1 μm. 
   
   
       6 . The method according to  claim 1  further comprising applying a dispersion layer (iii) having a layer thickness of less than 500 nm. 
   
   
       7 . The method according to  claim 1  further comprising applying a dispersion layer (iii) having a layer thickness of less than 200 nm. 
   
   
       8 . The method according to  claim 1  further comprising applying a dispersion layer (iii) having 5 wt. % to 98 wt. % of intrinsically conductive polymer, based on the mass of the dispersion layer (iii). 
   
   
       9 . The method according to  claim 1  wherein the intrinsically conductive polymer is selected from the group consisting of polyaniline (PAni), polythiophene (PTh), polypyrrole (PPy), poly(3,4-ethylenedioxythiophenes) (PEDT), polythieno-thiophene (PTT), derivatives thereof and mixtures thereof. 
   
   
       10 . The method according to  claim 1  wherein a polymer blend with a content of at least one intrinsically conductive polymer is used as the intrinsically conductive polymer. 
   
   
       11 . The method according to  claim 1 , wherein the base layer (i) contains a material selected from the group consisting of epoxide, epoxide composite, Teflon, cyanate ester, ceramic, cellulose, cellulose composite, cardboard and polyimide. 
   
   
       12 . The method according to  claim 1  wherein the base layer (i) has a layer thickness of 0.1 to 3 mm. 
   
   
       13 . The method according to  claim 1  wherein the layer (ii) has a layer thickness of 5 to 210 μm. 
   
   
       14 . The method according to  claim 1  further comprising providing a printed circuit board comprising a metal or alloy layer (iv), which is positioned between the layer (ii) and the layer (iii). 
   
   
       15 . The method according to  claim 14  wherein the layer (iv) comprises a material selected from the group consisting of silver, tin, gold, palladium and platinum. 
   
   
       16 . The method according to  claim 14  wherein the layer (iv) has a layer thickness of 10 to 800 nm.