Method for Obtaining a Cooking Vessel Having a Colored, Hard, Anodized Outer Surface

Abstract

Provided is a method for obtaining a cooking vessel that includes the following steps: producing a bowl having an aluminum outer surface and an inner surface; performing hard anodization of at least the outer surface of the bowl; and providing a sol-gel coating on the anodized outer surface. At least one coloring step is carried out following the hard anodization, the coloring step(s) being carried out before and/or during the sol-gel coating step. Also provided is a kitchen item or an electrical cooking appliance that includes a cooking vessel obtained by the above method.

The invention claimed is: 
     
         1 . A method for obtaining a cooking vessel, comprising the following steps:
 producing a bowl having an aluminum outer surface and an inner surface,   performing a hard anodization of at least the outer surface of the bowl,   providing a PTFE coating on the inner surface of the bowl,   providing a sol-gel coating on the anodized outer surface, wherein at least one coloring step is carried out on the anodized outer surface following the hard anodization before the sol-gel coating step,   wherein the coloring step comprises trapping inorganic pigments and/or organic pigments and/or organic dyes in a pore structure of the hard anodized layer, and   wherein the step of performing a hard anodization of the outer surface of the bowl is carried out prior to the step of providing a PTFE coating on the inner surface of the bowl.   
     
     
         2 . The method for obtaining a cooking vessel as in  claim 1 , wherein the coloring step or one of the coloring steps employs a coloring bath comprising inorganic pigments and/or organic pigments and/or organic dyes. 
     
     
         3 . A cooking vessel obtained from a method comprising:
 producing a bowl having an aluminum outer surface and an inner surface,   performing a hard anodization of at least the outer surface of the bowl,   providing a PTFE coating on the inner surface of the bowl,   providing a sol-gel coating on the anodized outer surface, wherein at least one coloring step is carried out on the anodized outer surface following the hard anodization before the sol-gel coating step,   wherein the coloring step comprises trapping inorganic pigments and/or organic pigments and/or organic dyes in a pore structure of the hard anodized layer, and   wherein the step of performing a hard anodization of the outer surface of the bowl is carried out prior to the step of providing a PTFE coating on the inner surface of the bowl.   
     
     
         4 . The cooking vessel as in  claim 3 , wherein the bowl is obtained by the stamping of a substrate having at least one aluminum surface. 
     
     
         5 . The cooking vessel as in  claim 4 , wherein the substrate has two aluminum surfaces. 
     
     
         6 . The cooking vessel as in  claim 4 , wherein the substrate is made of solid aluminum. 
     
     
         7 . The cooking vessel as in  claim 4 , wherein the substrate is formed by a colaminate having an aluminum surface and a stainless steel surface. 
     
     
         8 . The cooking vessel as in  claim 3 , wherein the bowl is made of die-cast aluminum. 
     
     
         9 . The cooking vessel as in  claim 3 , wherein the outer surface of the bowl has a brushed or micro-blasted surface. 
     
     
         10 . The cooking vessel as in  claim 3 , wherein the bowl comprises at least one insert made of a ferromagnetic material. 
     
     
         11 . A kitchen item comprising a cooking vessel according to  claim 3  and a handle attached to said cooking vessel by at least one rivet or by welding. 
     
     
         12 . An electric cooking appliance comprising a cooking vessel according to  claim 3  that is associated with a heating means. 
     
     
         13 . A cooking vessel comprising a bowl having an aluminum outer surface and an inner surface, a hard anodization layer formed on at least the aluminum outer surface of the bowl, a PTFE coating formed on the inner surface of the bowl after forming the hard anodization layer on the aluminum outer surface of the bowl, a sol-gel coating layer formed outside the hard anodization layer on the outer surface of the bowl, wherein the cooking vessel further comprises at least one coloring layer formed between the hard anodization layer and the sol-gel coating layer, and wherein the coloring layer comprises inorganic pigments and/or organic pigments and/or organic dyes trapped in a pore structure of the hard anodized layer. 
     
     
         14 . The cooking vessel as in  claim 13 , wherein the bowl is obtained by the stamping of a substrate having at least one aluminum surface. 
     
     
         15 . The cooking vessel as in  claim 13 , wherein the bowl is made of die-cast aluminum. 
     
     
         16 . The cooking vessel as in  claim 13 , wherein the outer surface of the bowl has a brushed or micro-blasted surface. 
     
     
         17 . The cooking vessel as in  claim 13 , wherein the bowl comprises at least one insert made of a ferromagnetic material. 
     
     
         18 . A kitchen item comprising a cooking vessel according to  claim 13  and a handle attached to said cooking vessel by at least one rivet or by welding. 
     
     
         19 . An electric cooking appliance comprising a cooking vessel according to  claim 13  that is associated with a heating means.