Patent ID: 7691308

Claim:
A method for producing a pharmaceutical piston stopper ( 2 ) made substantially from an elastomer and comprising a receiving cavity ( 6 ) for connecting with a displacement transferring element and a piston section ( 8 ) enclosed in a cap-shaped inert film ( 9 ), the piston section in a working position facing contents of a syringe or carpule cylinder ( 1 ), an outer circumference of the piston section with its inert film ( 9 ) abutting against the syringe or carpule cylinder ( 1 ), the piston stopper ( 2 ) having an uncoated sealing section ( 10 ) adjacent to the piston section ( 8 ), the method comprising: placing a layered arrangement comprising a non-vulcanized rubber sheet ( 7 ) and an inert film ( 9 ) into a forming tool and forming the layered arrangement into a piston stopper under the influence of pressure and heat during a forming operation, wherein the rubber sheet ( 7 ) is vulcanized and joined with the inert film ( 9 ) in an non-detachable manner; forming the complete contour of the piston stopper ( 2 ) during the forming operation from the layered arrangement up to a layered arrangement flange ( 16 ) protruding laterally beyond the piston stopper ( 2 ) and remaining in a region of a partition plane of the forming tool; producing the receiving cavity ( 6 ) in the rubber sheet ( 7 ) beyond the flange ( 16 ) in the piston section ( 8 ) during the forming operation; displacing at least a wall region of the sealing section ( 10 ) bordering the receiving cavity ( 6 ) and protruding beyond the flange ( 16 ) opposite the piston section ( 8 ) into the receiving cavity ( 6 ) during a separating operation; and separating the piston stopper ( 2 ) from the flange ( 16 ) by a blanking operation, so that in the sealing section ( 10 ) an annular continuous sealing zone ( 13 ) is formed that directly adjoins an edge of the inert film ( 9 ) that envelopes the piston section ( 8 ), the sealing zone in a working position abutting against the syringe or carpule cylinder ( 1 ).