Syringe
AssigneeTerumo Kabushiki Kaisha
InventorsToshiji Ichikawa, Teruko Watanabe
Life of this patent
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Abstract
A syringe includes an outer cylinder, a gasket having at least one part which slidably contacts the inner wall of the cylinder and being made of an elastomer material including a block copolymer having styrene units at both terminal ends, and means for sliding the gasket inside the cylinder. The slidably contacting part is compressed inside the cylinder at a compressiblity C (%) of a predetermined range selected according to a particular inner diameter of the cylinder. The product of the total contact area S (mm.sup.2) at the compressibility C (%) of the contacting part with the inner wall of the cylinder with the compressibility C (%) is about 350 to about 900.
Claims21
A syringe comprising an outer cylinder;
- a gasket having at least one part which slidably contacts the inner wall of said outer cylinder under the compressed condition forming a water-tight seal and being made of a colorable thermoplastic elastomer material including a block copolymer having a mean molecular weight between about 50,000 and about 200,000 and having the general formula
- (St).sub.m (A).sub.n (St).sub.m '
- (where St represents styrene units, A represents a unit derived from an unsaturated hydrocarbon having 2-5 carbon stoms or combinations thereof, and m, m' and n represent the mol % of each unit, the sum of m and m' being 2-20 mol %);
- and means for sliding said gasket inside said outer cylinder, said slidably contacting part being compressed inside said outer cylinder at a compressibility C (%) of a predetermined range selected according to a particular inner diameter of said outer cylinder, the product (S.times.C) of the total contact area S (mm.sup.2) of said slidably contacting part with the inner wall of said outer cylinder with said compressibility C (%) being about 350 to about 900, the value of S (mm.sup.2) being measured at said compressibility C (%).
A gasket for a syringe, made of a colorable elastomer material including a block copolymer having a mean molecular weight between about 50,000 and about 200,000 and having the general formula
- (St).sub.m (A).sub.n (St).sub.m'
- where St represents styrene units, A represents a unit derived from an unsaturated hydrocarbon having 2-5 carbon atoms or combinations thereof, and m, m' and n represent the mol % of each unit, the sum of m and m' being 2-20 mol %.
Dependencies are inferred from the claim text.