| abstract |
PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer stopper satisfying a desired material property of a stopper for a syringe assembly. SOLUTION: When a thermoplastic elastomer stopper 16 is held at 70 ° C. for 22 hours with a compression of 25%, the compression set is 50% or less. The hardness of the thermoplastic elastomer stopper of the present disclosure is 40 to 70 Shore A. The viscosity of the thermoplastic elastomer stoppers of the present disclosure is measured at 205 ° C. using a capillary rheometer (die: round hole length 20 mm / diameter 1 mm / 180 degree inlet, piston: d = 15 mm, melting time = 7 minutes). When the shear rate is 1,000 seconds -1 , the shear rate is 70.0 Pa · s or more, the shear rate 10,000 seconds -1 is 12.0 Pa · s or more, and the shear rate 50,000 seconds -1 is 3.0 Pa · s. s or more. [Selection diagram] FIG. 2A |