Method of manufacturing a food container

Abstract

A method of commercially manufacturing at low cost a vegetable-fiber-material made food container of practical strength includes the steps of: forming a board of a predetermined size from pulp and at least one kind of vegetable fiber material other than the pulp; coating the board with thermoplastic resin having a heat sealing property; providing cuts at four corners of the board to form sidewall pieces; and hot-pressing the board thus obtained using a pair of press dies to form the food container, the pair of dies being composed of female die and male die, wherein one of the pairs of opposing sidewall pieces is arranged to be erected prior to the other pair of opposing sidewall pieces and four corners are bonded correspondingly to each other by a hot press process in order to form the container.

1 . Manufacturing method of food containers or covers thereof comprising the steps of: 
 forming a board of a predetermined size from pulp and at least one kind of vegetable fiber material other than the pulp;    coating the board with thermoplastic resin having a heat sealing property;    providing cuts at four corners of the board to form sidewall pieces; and    hot-pressing the board thus obtained using a pair of press dies to form food containers or covers of the containers, a pair of dies being composed of female die and male die;    wherein one pair of the opposing sidewall pieces is arranged to be erected prior to the other pair of opposing sidewall pieces.    
   
   
       2 . The manufacturing method as claimed in  claim 1 , wherein said thermoplastic resin having the heat sealing property is applied to one of surfaces of the board to provide coating thereon.  
   
   
       3 . The manufacturing method as claimed in  claim 1 , wherein each of the cuts is formed so that a top of an angled section or a cut line reaches a corner of a bottom surface of the container to be formed.  
   
   
       4 . The manufacturing method as claimed in claim  3 , wherein each of the cuts is formed into V-shape at an angle between 20 and 60 degrees.  
   
   
       5 . The manufacturing method as claimed in  claim 3 , wherein the cuts are formed into funnel shapes or substantially Y-shapes.  
   
   
       6 . The manufacturing method as claimed in  claim 1 , wherein one pair of opposing sections of a concaved periphery of the female die is provided with a pair of protruded portions, and one pair of opposing sidewall pieces of the board placed on a pair of protruded portions are formed so as to be erected prior to the other opposing sidewall pieces.  
   
   
       7 . The manufacturing method as claimed in  claim 6 , wherein the opposing convex sections are away from the concave periphery of the female die by at least a distance corresponding to a sword guard shaped portion of the container to be formed.  
   
   
       8 . The manufacturing method as claimed in  claim 7 , wherein guides for holding side edges of the board is provided at the opposing protruded portions or at adjacent positions thereto.  
   
   
       9 . The manufacturing method as claimed in  claim 8 , wherein one of the other opposing surfaces of the concave periphery of the female die is provided with a guide to which one of the other side edges of the board abuts.  
   
   
       10 . The manufacturing method as claimed in  claim 1 , wherein one pair of the opposing sidewall pieces is bent before performing the pressing process, and arranged to be erected prior to the other pair of the opposing sidewall pieces.  
   
   
       11 . The manufacturing method as claimed in  claim 1 , wherein the pulp and at least one kind of the vegetable fiber material other than the pulp is a mixture of the pulp and the vegetable fiber material other than the pulp.  
   
   
       12 . The manufacturing method as claimed in  claim 11 , wherein the vegetable fiber material other than the pulp is reed, sugar corn, or kanaf.  
   
   
       13 . The manufacturing method as claimed in  claim 12 , wherein a rate of the pulp and the vegetable fiber material other than the pulp is defined such that the vegetable fiber material other than the pulp is between 20 and 80 wt % with respect to an entire mass of the board.  
   
   
       14 . The manufacturing method as claimed in  claim 1 , wherein the thermoplastic resin having the heat sealing property is polyethylene or polypropylene.