Patent Publication Number: US-2006005373-A1

Title: Metal container processing method

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a metal container processing method and more particularly, to a method of processing metal containers for cooking food in a microwave stove.  
      2. Description of the Related Art  
      Regular food containers suitable for use in a microwave stove to cook food are commonly made of ceramic and plastic materials. Consumers know that metal containers cannot be used in a microwave stove to cook food. Few consumers know the reason when metal containers cannot be used in a microwave stove to cook food. Because metal containers are commonly made of a metal sheet material by stamping, they have micro burrs and dents on the surface that are not visible to bare eyes. Under the radiation of microwaves in a microwave stove, these burrs and dents will cause sparks.  
      Further, a bakery may use metal molds for making cakes in a baking oven. These metal molds must be pre-heated to a certain temperature before filling cake materials. It takes much time to pre-heat metal molds in a baking oven. A microwave stove can greatly shorten the pre-heating time if metal molds are made usable in a microwave stove.  
     SUMMARY OF THE INVENTION  
      The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a metal container processing method, which is practical to make metal containers for use in a microwave stove to cook food. It is anther object of the present invention to provide a metal container processing method, which is easy and economic to perform. To achieve these and other objects of the present invention, the metal container processing method comprises the steps of metal container processing method includes steps of: a) stamping a metal sheet material into a blank container subject to the desired shape, b) removing sharp burrs and dents from the surface of the metal sheet material of the blank container with sodium nitrite solution, c) covering the surface of the metal sheet material of the blank container with a layer of surface coating of phosphorous compound, and d) covering said layer of surface coating with a layer of heat insulation coating containing Teflon and heat insulating material at the ratio of about 100:25˜35%.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic drawing showing sharp burrs and dents on the surface of the metal sheet material after stamping according to the present invention.  
       FIG. 2  is a schematic drawing showing sharp burrs and dents removed from the surface of the metal sheet material according to the present invention.  
       FIG. 3  is a schematic drawing showing a layer of surface coating covered on the surface of the metal sheet material and a layer of heat insulation coating coated on the layer of surface coating according to the present invention.  
       FIG. 4  is a block diagram explaining the metal container processing flow of the present invention.  
       FIG. 5  is an elevational view of a metal container made according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to FIGS.  1 ˜ 5 , the present invention is adapted to process a metal container  1  that can be used in a microwave stove to cook food. The metal container processing method includes the steps of shape forming  2 , deburring  3 , surface treatment  4 , and heat insulation coating  5 . During the step of shape forming, a metal sheet material  11  is stamped into a blank container subject to the desired shape. At this time, the metal sheet material  11  of the blank container has sharp burrs  12  and sharp dents  13  on the surface and sharp burrs  12  at the cutting edge that are not visible with bare eyes. These sharp burrs  12  and sharp dents  13  will cause sparks by microwave molecules in a microwave stove. Therefore, the step of deburring  3  is necessary to remove the sharp burrs  12  and sharp dents  13  from the metal sheet material  11  of the blank container. After deburring, it proceeds to the step of surface treatment  4  where a layer of surface coating  14  is covered on the surface of the metal sheet material  11  of the blank container to fill up the gaps in the capillary holes on the surface of the metal sheet material  11  of the blank container, thereby providing a smooth surface. After surface treatment  4 , it proceeds to the step of heat insulation coating  5  to cover a layer of heat insulation coating  15  on the layer of surface coating  14 .  
      During the step of deburring  3 , sodium nitrite solution is applied to remove the sharp burrs  12  and sharp dents  13  from the metal sheet material  11  of the blank container. During the step of surface treatment  4 , phosphorous compound is coated on the surface of the metal sheet material  11  of the blank container to form the desired layer of surface coating  14 . During the step of heat insulation coating  5 , a coating material containing Teflon and heat insulating material at the ratio of about 100:25˜35% is coated on the surface of the layer of surface coating  14 .  
      The metal container  1  thus obtained can be used to cook food in a microwave stove, baking oven, gas range, as well as electric stove.