Abstract: A medical rubber part in which non-elution characteristics are maintained even after sterilization with gamma ray, a packaging article for the medical rubber part, and a medical rubber composition for manufacturing the medical rubber part can be provided or implemented. The medical rubber composition can contain or comprise: a (a) base polymer containing a halogenated isobutylene-isoprene rubber; a (b) polyethylene; and a (c) triazine derivative as a crosslinking agent. A proportion of the triazine derivative contained per 100% by mole of a halogen of the halogenated isobutylene-isoprene rubber contained in the (a) base polymer can be 1% by mole to 15% by mole.

Abstract: A sterilization method for a medical rubber part in which non-elution characteristics can be maintained even after sterilization with gamma ray. The sterilization method for a medical rubber part can include irradiating, with gamma ray, a packaging article for a medical rubber part made from an elastomer that contains a polyethylene, the packaging article accommodating a plurality of the medical rubber parts.

Abstract: An object of the present invention is to provide a medical rubber composition having excellent non-elution characteristic and gas permeability. The present invention provides a medical rubber composition containing: (a) a butyl rubber, (b) a diene-based rubber containing polybutadiene, (c) a peroxide-based crosslinking agent, and (d) a co-crosslinking agent, wherein an amount of (b) the diene-based rubber in 100 parts by mass of the rubber component composed of (a) the butyl rubber and (b) the diene-based rubber is 15 parts by mass or more and 90 parts by mass or less, and a mass ratio ((d)/(c)) of (d) the co-crosslinking agent to (c) the peroxide-based crosslinking agent is 1.2 or more and 25 or less.

Abstract: An object of the present invention is to provide a medical rubber composition having excellent non-elution characteristic and gas permeability. The present invention provides a medical rubber composition containing: (a) a butyl rubber, (b) a diene-based rubber containing polybutadiene, (c) a peroxide-based crosslinking agent, and (d) a co-crosslinking agent, wherein an amount of (b) the diene-based rubber in 100 parts by mass of the rubber component composed of (a) the butyl rubber and (b) the diene-based rubber is 15 parts by mass or more and 90 parts by mass or less, and a mass ratio ((d)/(c)) of (d) the co-crosslinking agent to (c) the peroxide-based crosslinking agent is 1.2 or more and 25 or less.

Abstract: An object of the present invention is to provide a medical rubber composition having excellent gas permeation resistance. The present invention provides a medical rubber composition containing (a) a base polymer containing a halogenated butyl rubber, and (b) a liquid polymer.

Abstract: A gasket having a novel structure ensuring both the gas tightness and the low-friction slidability is provided. A sliding portion of the gasket (13) includes at least a first annular projection (17A), an annular recess and a second annular projection (17B) arranged in this order in a direction rearward from a distal portion of the gasket serving as a liquid contact portion. The first projection (17A) is designed so that a first peak appears adjacent the distal portion of the gasket when the gasket is fitted in the syringe barrel (11) and a product ? of a contact pressure P1f and a width D1f of the first peak is 0.4???1.0 as determined by an FEM analysis.

Abstract: A gasket (10) for a prefilled syringe is provided, which has a generally cylindrical outer shape, and includes a liquid contact portion (13) provided on one of opposite end faces, a thread hole (15) provided in the other end face for attachment of a plunger, and at least two annular projections (17A, 17B) provided on a peripheral surface (16) and spaced from each other by an annular trough (18) in a gasket height direction (gasket axial direction) extending from the one end face to the other end face, wherein a diameter difference (A) (=a1?a2) between a diameter (a1) of the annular projections (17A, 17B) and a diameter (a2) of the annular trough and a diameter difference (B) (=b1?b2) between a thread root diameter (b1) and a thread ridge diameter (b2) of an internal thread portion of the thread hole satisfy a ratio relationship of A:B=1:(2 to 4).

Abstract: A gasket having a novel structure ensuring both the gas tightness and the low-friction slidability is provided. A sliding portion of the gasket (13) includes at least a first annular projection (17A), an annular recess and a second annular projection (17B) arranged in this order in a direction rearward from a distal portion of the gasket serving as a liquid contact portion. The first projection (17A) is designed so that a first peak appears adjacent the distal portion of the gasket when the gasket is fitted in the syringe barrel (11) and a product ? of a contact pressure P1f and a width D1f of the first peak is 0.4???1.0 as determined by an FEM analysis.