| abstract |
A gasket capable of providing an excellent slidability without adding lubricant and holding a sealability and installed slidably in the outer tube of a syringe, wherein at least the outer periphery of a gasket body is covered with a resin film formed of a material lower in coefficient of friction than the material of the gasket body and, where the surface roughness of the resin film on the outer tube side is (Ra1) and the surface roughness of the resin film on the gasket body side is (Ra2), the requirement for the relation of 1.5Ra1 = Ra2 is satisfied, whereby the resin film is prevented from being peeled off the gasket body and a formed defect such as pin holes can be prevented from occurring. |