Textured decorative plating on plastic components

Abstract

A relatively inexpensive process for making plastic components having textured chrome finishes that may have fine, crisp, clean lines and intricate details includes steps of electroplating a layer of etchable metal on a surface of a plastic article, typically preserving the surface of the etchable metal, etching a desired relief pattern on the layer of etchable metal, typically cleaning and activating the surface of the relief patterned etched metal layer, and electroplating a layer of decorative metal on the relief patterned etched metal layer.

1 . A process for preparing a metal plated plastic article having a desired relief pattern in a surface of the article, comprising: 
 electroplating a layer of etchable metal on the plastic article;    etching the desired relief pattern on the layer of etchable metal; and    depositing a finish layer over the patterned metal layer.    
   
   
       2 . The process of  claim 1 , further comprising cleaning the surface of the article before electroplating an etchable metal layer on the article.  
   
   
       3 . The process of  claim 1 , further comprising conditioning the surface of the article before electroplating an etchable metal layer on the article.  
   
   
       4 . The process of  claim 1 , further comprising etching the surface of the plastic article before electroplating the etchable metal layer on the article.  
   
   
       5 . The process of  claim 1 , further comprising neutralizing the surface of the plastic article before electroplating the etchable metal layer on the article.  
   
   
       6 . The process of  claim 1 , further comprising catalyzing the surface of the plastic article before electroplating the etchable metal layer on the article.  
   
   
       7 . The process of  claim 1 , further comprising contacting the surface of the plastic article with an accelerator solution before electroplating the etchable metal layer on the article.  
   
   
       8 . The process of  claim 1 , further comprising electroless plating the surface of the plastic article before electroplating the etchable metal layer on the article.  
   
   
       9 . The process of  claim 1 , wherein the etchable metal layer is electroplated onto the article to a thickness of from about 50 micrometers to about 500 micrometers.  
   
   
       10 . The process of  claim 1 , wherein the etchable metal layer on the surface of the article is activated before the desired relief pattern is etched on the etchable metal layer.  
   
   
       11 . The process of  claim 10 , wherein the etchable metal layer is activated by contacting an exposed surface of the etchable metal layer with an activation solution comprising from about 1% by weight to about 10% by weight hydrogen peroxide (H 2 O 2 ) and from about 5% by volume to about 20% by volume sulfuric acid (H 2 SO 4 ).  
   
   
       12 . The process of  claim 11 , wherein the etchable metal layer is contacted with the activation solution for about 5 seconds to about 60 seconds.  
   
   
       13 . The process of  claim 1 , wherein an exposed surface of the etchable metal layer is contacted with an aqueous corrosion inhibitor solution before the desired relief pattern is etched on the etchable metal layer.  
   
   
       14 . The process of  claim 13 , wherein the surface of the etchable metal layer is contacted with the aqueous corrosion inhibitor solution for a period of from about 1 second to about 10 minutes.  
   
   
       15 . The process of  claim 13 , wherein the aqueous corrosion inhibitor solution comprises at least one corrosion inhibiting agent selected from the group consisting of benzotriazole, 2-mercaptobenzimidazole, 2-mercapatobenzothiazole, 2-mercaptobenzoxazole and their derivatives.  
   
   
       16 . The process of  claim 13 , wherein the aqueous corrosion inhibitor solution comprises benzotriazole at a concentration of at least 10 mg/L.  
   
   
       17 . The process of  claim 1 , wherein the etching of the desired relief pattern on the etchable metal layer is achieved by selectively masking sections of the surface of the etchable metal while exposing other sections of the surface of the etchable metal, and contacting the masked surface with an etchant, the mask being resistant to the etchant, whereby only the exposed sections of the surface of the etchable metal are etched.  
   
   
       18 . The process of  claim 17 , wherein the etching of the sections of the etchable metal layer that are exposed through mask is achieved by contacting the etchable metal layer with a chemical etchant.  
   
   
       19 . The process of  claim 18 , wherein the etchant is a solution comprising from 50 g/L to 500 g/L ferric chloride (FeCl 3 ).  
   
   
       20 . The process of  claim 18 , wherein the etchant is a solution comprising from about 5% by weight to about 20% by weight hydrogen peroxide (H 2 O 2 ) by weight and from about 15% by volume to about 30% by volume sulfuric acid (H 2 SO 4 ).  
   
   
       21 . The process of  claim 18 , wherein etchant is a solution comprising from about 15% by weight to about 25% by weight ammonium persulfate and from about 15% by volume to about 30% by volume sulfuric acid (H 2 SO 4 ).  
   
   
       22 . The process of  claim 18 , wherein etchant is a solution comprising from about 250 g/L to about 380 g/L nitric acid (HNO 3 ).  
   
   
       23 . The process of  claim 18 , wherein etchant is a solution comprising from about 150-350 g/L of CrO 3  and from about 200 to about 400 g/L of H 2 SO 4 .  
   
   
       24 . The process of  claim 19 , wherein the contacting of the exposed surface of the etchable metal layer with the etching solution is for a period of from about 30 seconds to about 2 minutes.  
   
   
       25 . The process of  claim 20 , wherein the contacting of the exposed surface of the etchable metal layer with the etching solution is for a period of from about 30 seconds to about 2 minutes.  
   
   
       26 . The process of  claim 21 , wherein the contacting of the exposed surface of the etchable metal layer with the etching solution is for a period of from about 30 seconds to about 2 minutes.  
   
   
       27 . The process of  claim 22 , wherein the contacting of the exposed surface of the etchable metal layer with the etching solution is for a period of from about 30 seconds to about 2 minutes.  
   
   
       28 . The process of  claim 23 , wherein the contacting of the exposed surface of the etchable metal layer with the etching solution is for a period of from about 30 seconds to about 2 minutes.  
   
   
       29 . The process of  claim 18 , wherein the contacting of the exposed surface of the etchable metal layer with the etchant solution is sufficient to etch to a depth of from about 20 micrometers to about 400 micrometers.  
   
   
       30 . The process of  claim 29 , further comprising rinsing the etched metal layer with water, and contacting the etched metal layer with a solution containing from about 25% to about 50% HCl by volume.  
   
   
       31 . The process of  claim 30 , further comprising immediately rinsing the exposed surface of the etched metal layer with water after contacting the etched metal layer with a solution containing HCl, and drying the rinsed surface.  
   
   
       32 . The process of  claim 30 , wherein the rinsed surface is dried with compressed, oil-free air.  
   
   
       33 . The process of  claim 17 , further comprising removing the remaining sections of the inorganic chemical resistant material from the etched metal layer by contact with a stripping solvent.  
   
   
       34 . The process of  claim 33 , further comprising cleaning and activating the surface of the etched metal layer before electroplating chrome on the etched metal layer.  
   
   
       35 . The process of  claim 34 , wherein the cleaning of the etched metal layer comprises removing organic residues with a cleaning solution containing at least one organic solvent and at least one surfactant; rinsing the cleaning solution from the etched metal layer with a water-soluble organic solvent; and rinsing the water-soluble organic solvent from the etched metal layer with water.  
   
   
       36 . The process of  claim 35 , wherein the cleaning solution comprises 20-30% by weight ethyl ethanol, 10-40% by weight heptane, 2-10% by weight triethanolamine, 1-3% by weight non-ionic surfactant, and 10-50% by weight p-mentha-1,8-diene.  
   
   
       37 . The process of  claim 35 , wherein the cleaning further comprises mechanical agitation, ultrasonic agitation, or brushing.  
   
   
       38 . The process of  claim 35 , wherein the water-soluble solvent is selected from the group consisting of ethanol, 1-propanol, 2-propanol and combinations thereof.  
   
   
       39 . The process of  claim 35 , further comprising supplemental removal of inorganic contaminants from the etched metal surface by contact with an alkaline cleaning solution, and rinsing of the alkaline cleaning solution from the etched metal surface with water.  
   
   
       40 . The process of  claim 35 , further comprising removal of corrosion or tarnish stains by contacting the etched metal layer with an acid solution and rinsing the acid solution and rinsing the acid solution from the etched metal layer.  
   
   
       41 . The process of  claim 40 , wherein the acid solution comprises 20-50% by volume HCl or 15-30% by volume H 2 SO 4 .  
   
   
       42 . The process of  claim 34 , wherein activating the surface of the etched metal layer comprises contacting the surface of the etched metal layer with an activating solution containing 1-15% by weight of hydrogen peroxide (H 2 O 2 ) and 10-30% by volume sulfuric acid (H 2 SO 4 ) at about ambient temperature for about 5-60 seconds, and then rinsing the activating solution from the surface of the etched metal layer with water.  
   
   
       43 . The process of  claim 1 , further comprising acid copper electroplating a thin layer of copper on the etched metal layer before electroplating a finish layer on the etched metal layer, whereby light scratches left on the surface of the etched metal layer during etching, cleaning or activating are leveled.  
   
   
       44 . The process of  claim 1 , further comprising electroplating at least one layer of nickel on the etched metal layer before electroplating a finish layer on the etched metal layer.  
   
   
       45 . The process of  claim 1 , further comprising electroplating a layer of bright nickel on the etched metal layer before electroplating a finish layer on the etched metal layer.  
   
   
       46 . The process of  claim 1 , further comprising electroplating a layer of semi-bright nickel on the etched metal layer before electroplating a finish layer on the etched metal layer.  
   
   
       47 . The process of  claim 1 , further comprising electroplating a layer of microporous nickel on the etched metal layer before electroplating a finish layer on the etched metal layer.  
   
   
       48 . The process of  claim 1 , further comprising electroplating a layer of semi-bright nickel, a layer of bright nickel, and a layer of microporous nickel on the etched metal layer before electroplating the finish layer on the etched metal layer.  
   
   
       49 . The process of  claim 1 , further comprising electroplating a layer of satin nickel on the etched metal layer before electroplating the finish layer on the etched metal layer.  
   
   
       50 . The process of  claim 1 , further comprising applying a chrome activator to the surface of the etched metal layer or to a surface of a metal layer electroplated directly on or indirectly on the etched metal layer.  
   
   
       51 . The process of  claim 1 , wherein etching of the desired pattern is achieved using a laser.  
   
   
       52 . The process of  claim 1 , wherein the etching of the desired pattern is achieved using mechanical abrasion.  
   
   
       53 . The process of  claim 52 , wherein the mechanical abrasion is sanding-blasting.  
   
   
       54 . The process of  claim 1 , wherein the layer of etchable metal is a layer of copper.  
   
   
       55 . The process of  claim 34 , further comprising applying a corrosion inhibitor to a surface of the etched metal layer, transporting or storing the article after applying the corrosion inhibitor, and removing the corrosion inhibitor after transporting or storing the article and before activating the surface of the etched metal layer.  
   
   
       56 . The process of clam  1 , wherein the finish layer is a metal layer.  
   
   
       57 . The process of  claim 56 , wherein the finish metal layer is selected from the group consisting essentially of chrome, rhodium, gold, platinum, palladium, silver, nickel and black nickel.  
   
   
       58 . The process of  claim 56 , wherein an organic overcoat is deposited over the finish metal layer.  
   
   
       59 . The process of  claim 1 , wherein the finish layer is an organic coating.  
   
   
       60 . A plastic article having a decorative relief pattern, comprising: 
 a plastic substrate;    an etched metal layer disposed on the substrate; and    a finish layer disposed over the etched metal layer.