| abstract |
The invention provides a propylene polymer composition which is excellent in transparency, flexibility, heat resistance, scratch resistance, and rubber elasticity and is well balanced among them, and medical tubes made from the composition. The propylene polymer composition is characterized by satisfying the following requirements (A), (B), (C), and (D): (A) in dynamic viscoelasticity measurement (10 rad/s) in torsion mode, the loss tangent (tanδ) has a peak within the range of -20 to 25°C and the value of the peak is 0.5 or above, (B) the storage modulus (G) as determined at 20 °C by the above viscoelasticity measurement ranges from 1.0 x 107 to 4.9 x 108 dyn/cm2, (C) the needle penetration temperature (°C) as determined according to JIS K7196 is 60 to 160°C, and (D) the residual strain is 30 % or below as determined by imparting a strain of 100 % to a specimen with a chuck-chuck distance of 30 mm at a rate of pulling of 30 mm/min, keeping the specimen in the strained state for 10 minutes, and then measuring the residual strain 10 minutes after the unloading. The medical tubes are characterized by being made from the propylene polymer composition. |