Catheter prodn. having flexible gradient - by extrusion of hard and soft plastics in varying proportion

摘要

In the prodn. of catheters having a hard inner tube and a soft outer tube by using two extruders, the hard material supply to the inner tube extrusion die is increased from 0 to 100% while soft material supply to the outer die is decreased from 100 to 0%. Pref. the inner tube material is POM, polyamide or polycarbonate. ADVANTAGE - The process allows mfr. of catheter tubes having predetermined hard and soft cross-sectional proportions along their length and thus a flexibility gradient