Packaging container, packaging body including the same, and packaging method

Abstract

The present invention provides a tray for which sufficient adhesion strength can be obtained when thermal bonding between the tray and a stretch film is conducted using a slanted heat roller. The tray 10 is provided with a bottom panel 11, a wall panel 12, and a flange 13. Bottom panel 11 is a panel for placing an article to be packaged. Wall panel 12 extends upward from bottom panel 11 in such a manner that it surrounds bottom panel 11. Flange 13 extends outward from the upper end part of wall panel 12. Flange 13 further has a curved part 13 a on its wall panel side and a slanted part 13 b positioned to the outside of curved part 13 a. The cross section of the upper surface of slanted part 13 b is substantially a straight line and curved part 13 a is formed such that wall panel 12 and slanted part 13 b have an uninterrupted shape.

What is claimed is:  
     
         1 . A packaging container, comprising: 
 a bottom panel for placing an article to be packaged,    a wall panel having an upper end part, said wall panel extending upward from said bottom panel such that said wall panel surrounds said bottom panel; and    a flange extending outward from said upper end part of said wall panel, said flange having a curved part on said wall panel side and a slanted part positioned outside of said curved part, said curved part having an upper surface of which a cross section is substantially straight, said curved part being formed such that said wall panel and said slanted part define a continuous shape.    
     
     
         2 . A packaging container as recited in  claim 1 , wherein 
 said slanted part is at a slant angle in a range from 20 to 60 degrees with respect to said bottom panel.    
     
     
         3 . A packaging container as recited in  claim 1  or  2 , wherein 
 a width of said slanted part is 2 mm or greater.  
 
     
     
         4 . A packaging container as recited in any one of  claims 1  to  3 , wherein 
 a bonding agent is applied to a surface of said flange.  
 
     
     
         5 . A packaging body, comprising: 
 a packaging container as recited in any one of  claims 1  to  4 ; and    a film covering an upper surface of said packaging container, a periphery of said film being bonded to said flange.    
     
     
         6 . A packaging body as recited in  claim 5 , wherein 
 the periphery of said film follows said curved part of said flange without any air gaps and is bonded to said slanted part of said flange.    
     
     
         7 . A packaging body as recited in  claim 5  or  6 , wherein said flange further has a protruding part that is positioned on an outer peripheral side of said slanted part for cutting the film.  
     
     
         8 . A packaging body as recited in any one of  claims 5  to  7 , wherein 
 said film is thermally bonded to said flange by pressing a slanted hot body against said slanted part while the periphery of said film is in close contact with said curved part and said slanted part.  
 
     
     
         9 . A packaging method, comprising: 
 a first step in which an article to be packaged is placed in a packaging container having a slanted flange at its periphery,    a second step in which a film is supplied above the packaging container and tension is applied to the film,    a third step in which the packaging container is raised and the flange is made to touch against the tensioned film; and    a fourth step in which a hot body is pressed against the flange touching the film at a slant angle larger than the slant angle of the flange.    
     
     
         10 . A packaging method as recited in  claim 9 , wherein 
 the hot body is pressed against the flange such that a width of a portion where the flange and the hot body contact each other is 2 mm or greater in said fourth step.