| 摘要 |
A syringe comprises an outer cylinder; a gasket having at least one part which slidably contacts the inner wall of the cylinder in a compressed condition forming a watertight seal; and a plunger for sliding the gasket inside the cylinder. The gasket is made of a colourable thermoplastic elastomer material including a block copolymer of mean mol.wt. 50,000- 200,000 and having the formula: (St)m-(A)n-(St)m' (where St represents styrene units; A represents a unit derived from one or more 2-5C unsatd. hydrocarbon; and m, m' and n represent the mol.% of each unit, the sum of m and m' being 2-20 mol.%). The slidable contacting part is compressed inside the cylinder at a compressibility C% such that the product CxS is 350-900, where S is the total contact area (sq.mm.) of the slidable contacting part with the inner wall of cylinder measured at the compressibility C. The syringe is air- and water-impermeable while retaining easy slidability. The gasket material does not contain elutable sulphur or heavy metals, and shows a negative reaction to haemolysis, so that it may be safely used for medical injections and for drawing blood. Further, since it is made of thermoplastic material it can be easily and quickly mfd. by injection moulding; and the prod. is heat resistant so that it can easily withstand gamma-ray irradiation and the temps. of sterilisation with ethylene oxide, transportation and storage. |
