Vial rubber-stopper

Abstract

There is provided a rubber stopper used to seal an opened portion of vials and syringes for keeping medical liquid and, in particular, to a rubber stopper in which stoppering properties can be improved without damaging sealing properties in the absence of silicone coating. A vial rubber stopper 1 comprises a disc-like top portion 3 and a cylindrical leg portion 2 of smaller diameter compared with that of the disc-like top portion, which is protruded from a bottom surface of the disc-like top portion 3 to shape into a flange 2 A upward. An under-flange ring portion 3 A connected to a flange bottom surface 2 B is divided on an outer peripheral surface of the cylindrical leg portion 2 , and the first ring-like raised portion 3 B and the second ring-like raised portion 3 C are formed downward of the under-flange ring portion 3 A in the circumferential direction. An upper surface of the disc-like top portion 3 including a flange-upper surface, a maximum diametral portion of a flange-peripheral surface, a bottom surface of the disc-like top portion 3 located inside of the cylindrical leg portion 2 and a surface of the cylindrical leg portion 2 other than the under-flange ring portion 3 A are laminated with a synthetic resin to leave the flange bottom surface and the surface of the under-flange ring portion 3 A as a naked rubber stock.

1 . A vial rubber stopper comprises a disc-like top portion and a cylindrical leg portion of smaller diameter compared with that of the disc-like top portion, which is protruded from a bottom surface of the disc-like top portion to shape into a flange upward, characterized in that an under-flange ring portion connected to a flange bottom surface is divided on an outer peripheral surface of the cylindrical leg portion, and at least one ring-like raised portion is arranged downward of the under-flange ring portion in the circumferential direction, while an upper surface of the disc-like top portion including a flange-upper surface, a maximum diametral portion of a flange-peripheral surface, a bottom surface of the disc-like top portion located inside of the cylindrical leg portion and a surface of the cylindrical leg portion other than the under-flange ring portion are laminated with a synthetic resin to leave the flange bottom surface and the surface of the under-flange ring portion as a naked rubber stock. 
   
   
       2 . A vial rubber stopper claimed in  claim 1  in which shortest interval from a bottom surface of said flange to a ring-like raised portion nearest thereto is fallen in a range from ⅓ to 5 times of the ring-like raised portion. 
   
   
       3 . A vial rubber stopper claimed in  claim 1  in which maximum diameter of a ring-like raised portion nearest to a bottom surface of said flange is 1 to 30% larger than a caliber of an opened portion of a vial to be inserted thereto said cylindrical leg portion. 
   
   
       4 . A vial rubber stopper claimed in  claim 1  in which said under-flange ring portion is divided between a bottom surface of said flange and an upper edge portion of a synthetic resin film to be laminated on an outer peripheral surface of said cylindrical leg portion. 
   
   
       5 . A vial rubber stopper claimed in  claim 1  in which a material of said synthetic resin film is either a fluororesin or Ultra High Molecular Weight polyethylene. 
   
   
       6 . A vial rubber stopper claimed in  claim 1  in which press molding of said cylindrical leg portion and lamination of a synthetic resin film onto said cylindrical leg portion are conducted at the same time, while press molding of said disc-like top portion, lamination of a synthetic resin film onto said disc-like top portion and unification of said disc-like top portion and said cylindrical leg portion are conducted at the same time.