Dlc film coated plastic container, and device and method for manufacturing the plastic container

Abstract

The present invention provides method of DLC film coating a plastic container by DLC film coating the container in an apparatus, where the apparatus comprises a container side electrode which forms one portion of a pressure-reducing chamber and a facing electrode, where the container side electrode is formed so that the average inner hole diameter (R 2 ) of the inner wall surrounding a neck portion is smaller than the average inner hole diameter (R 1 ) of the inner wall surrounding the body portion, and the average distance (d 2 ) between the outer wall of the container and the inner wall of the container side electrode in a horizontal cross section with respect to the vertical direction of the container at the neck portion becomes longer than the average distance (d 1 ) between the outer wall of the container and the inner wall of the container side electrode.

1 - 23 . (canceled) 
     
     
         24 . A method of DLC film coating a plastic container, comprising:
 DLC film coating said container in an apparatus, wherein said apparatus comprises:   a container side electrode which forms one portion of a pressure-reducing chamber which houses a container formed from plastic in which the cross-sectional area of an opening of said container is smaller than the cross-sectional area of a horizontal cross section at a body portion of said container and a neck portion is provided between said opening and said body portion, and a facing electrode which faces said container side electrode and is arranged inside said container or above said opening, wherein said container side electrode and said facing electrode are made to face each other via an insulating body which forms a portion of said pressure-reducing chamber, source gas supply means which supply a source gas that is converted to plasma for coating the inner wall surface of said container with a diamond like carbon (DLC) film includes a supply gas inlet pipe provided in said pressure-reducing chamber to introduce said source gas supplied to said pressure-reducing chamber to the inside of said container, exhaust means which exhaust gas inside said pressure-reducing chamber from above the opening of said container are provided, and high frequency supply means which supply a high frequency is connected to said container side electrode;   wherein said container side electrode is formed so that the average inner hole diameter (R 2 ) of the inner wall surrounding said neck portion is smaller than the average inner hole diameter (R 1 ) of the inner wall surrounding said body portion, and the average distance (d 2 ) between the outer wall of said container and the inner wall of said container side electrode in a horizontal cross section with respect to the vertical direction of said container at said neck portion becomes longer than the average distance (d 1 ) between the outer wall of said container and the inner wall of said container side electrode in a horizontal cross section with respect to the vertical direction of said container at said body portion.   
     
     
         25 . The method of  claim 24 , wherein said average distance d 2  is formed to be a distance which suppresses the rise in plasma density accompanying the rise in pressure of the source gas converted to plasma at said neck portion inside said container in order to form a roughly uniform plasma density inside said container. 
     
     
         26 . The method of  claim 24 , wherein said average distance d 2  is formed to be the same as or shorter than the distance at which the strength of ionic impacts due to collisions of the ions of the source gas converted to plasma with the inner wall surface of said container forms an ionic impact strength capable of forming a DLC film having a prescribed lower limit oxygen barrier property, and said average distance d 2  is formed to be the same as or longer than the distance at which the entire wall surface of said container has a roughly uniform color by suppressing coloration of a specific part of said container from said neck portion to said opening caused by plasma damage or plasma etching of the inner wall surface of said container due to the increase in plasma density accompanying the increase in pressure of the source gas converted to plasma in said neck portion inside said container. 
     
     
         27 . The method of  claim 24 , wherein said average distance d 2  is formed to be a distance at which the DLC film coated plastic container secures a prescribed oxygen barrier property and the entire wall surface of said DLC film coated plastic container has a roughly uniform color. 
     
     
         28 . The method of  claim 24 , wherein the average diameter of said body portion of said container is made D 1 , the average diameter of said neck portion is made D 2 , and in the case where K is made an offset coefficient that satisfies the relationship of Equation 1, the offset coefficient K satisfies the relationship of Equation 2 or Equation 3, and said average distance d 2  forms the d 2  determined from Equation 1:
     d 2= K ×( D 1− D 2)/2 +d 1  Equation 1
 
   0.29 ≦K≦ 0.79 where 0.2 mm≦ d 1≦2.0 mm Equation 2
 
   0.11≦ K≦ 0.51 where 2.0 mm< d 1≦4.0 mm.  Equation 3
 
 
     
     
         29 . The method of  claim 24 , wherein the average diameter of said body portion of said container is made D 1 , the average diameter of said neck portion is made D 2 , an offset coefficient that satisfies the relationship of Equation 4 is made K, and when a of Equation 4 is a container compensation coefficient that takes into account the container shape dependency satisfying Equation 5, the offset coefficient K satisfies the relationship of Equation 2 or Equation 3, and said average distance d 2  forms the d 2  determined from Equation 4:
   0.29≦ K≦ 0.79 where 0.2 mm≦ d 1≦2.0 mm  Equation 2
 
   0.11≦ K≦ 0.51 where 2.0 mm< d 1≦4.0 mm  Equation 3
 
     d 2=α K ×( D 1− D 2)/2+ d 1  Equation 4
 
   α=( D 1/ D 2) 2 /3.54.  Equation 5
 
 
     
     
         30 . The method of  claim 24 , wherein said container has an axial symmetrical shape with respect to the central axis of the vertical direction, and the inner wall shape of said container side electrode is formed to be an axial symmetrical shape with respect to said central axis when said container is housed. 
     
     
         31 . The method of  claim 24 , wherein when said container is housed in said container side electrode, the inner wall of said container side electrode surrounding said body portion of said container is formed to have a cylindrical shape, the inner wall of said container side electrode surrounding said neck portion of said container is formed to have a truncated cone shaped cylindrical shape in which the diameter becomes smaller toward the container opening, and the inner wall of said container side electrode is formed to have a continuous shape. 
     
     
         32 . The method of  claim 31 , wherein the inner wall of said container side electrode surrounding the opening of said container is formed to have a cylindrical shape. 
     
     
         33 . The method of  claim 24 , wherein said body portion of said container has a square tube shape, the inner wall of said container side electrode surrounding said body portion of said container is formed to have a square tube shape, the inner wall of said container side electrode surrounding said neck portion of said container is formed to have a truncated pyramid shaped square tube shape in which the diameter becomes smaller toward the container opening, a square tube shape or a shape which is a combination of these, and the inner wall of said container side electrode is formed to have a continuous shape. 
     
     
         34 . The method of  claim 33 , wherein the inner wall of said container side electrode surrounding the opening of said container is formed to have a square tube shape. 
     
     
         35 . The method of  claim 24 , wherein said container side electrode is formed so that d 1  is greater than 0 mm and less than or equal to 4 mm. 
     
     
         36 . The method of  claim 24 , wherein said container is a container for beverages.