Patent ID: 9623186
Date: 2017-04-18
CPC Classifications: A61M,F16J

Claim:
1. A medical syringe comprising: a tubular syringe barrel; a plunger combined with the syringe barrel and movable in the syringe barrel; and a gasket attached to a distal end of the plunger, the gasket comprising: a rubber body having a liquid contact portion and a sliding portion to be brought into contact with an inner surface of the tubular syringe barrel; and a lamination film provided on a surface of the rubber body; wherein the sliding portion includes at least a first annular projection, an annular recess and a second annular projection arranged in this order in a direction rearward from a distal portion of the gasket serving as the liquid contact portion; wherein a diameter of the first annular projection is smaller than a diameter of the second annular projection; wherein the first projection is designed so that a distal peak appears adjacent the distal portion of the gasket when the gasket is fitted in the syringe barrel and a product a of a contact pressure P wherein a product β of a contact pressure P wherein an edge portion of the first projection adjacent to the distal portion has a curvature radius of not greater than 1.2 mm, and wherein the lamination film is made of PTFE.