| 摘要 |
PURPOSE:To provide a needle capable of being manufactured simply and easily in mass production at a low cost by using a polypropylene resin having the stereospecific degree of the n-hexane insoluble matter, the bending initial elastic modulus, and the Rockwell hardness (R scale) of specific values for the thermoplastic resin of a medical needle injection-molded into a needle shape. CONSTITUTION:A polypropylene resin having the stereospecific degree of the n-hexane insoluble matter of 98% or above, the bending initial elastic modulus of 20000kg/cm<3> or above, and the Rockwell hardness (R scale) of 105 or above is used for the thermoplastic resin of a medical needle 1 injection-molded into a needle shape with a thermoplastic resin, or a polypropylene resin having the bending initial elastic modulus of 24000kg/cm<3> or above, the Rockwell hardness (R scale) of 108 or above, the crystallinity of 70% or above, and the ratio of the weight average molecular weight against the number average molecular weight of 8 or above is used. This plastic needle has sufficient rigidity and excellent heat resistance, and it can be simply and surely sterilized when it is heated and disinfected. |
