BALLOON AND BALLOON CATHETER

PROBLEM TO BE SOLVED: To provide a strong balloon having high separation resistance and wear resistance by composing it from an inner layer made of a crystalline plastic resin, an outer layer made of a highly soft resin, and an intermediate layer made of a relatively soft polymer alloy. SOLUTION: A balloon 1 is made of a three-layered thin-walled member consisting of an inner layer 7, an intermediate layer 8, and an outer layer 9. The inner layer 7, being the part securing the strength of the balloon 1, is given high strength and made thin as it is made from a crystalline plastic resin subjected to a drawing process. The intermediate layer 8, in order to serve to bond the outer layer 9 strongly to the inner layer 7, is made from a relatively soft polymer allay containing 60 to 70 parts by weight of the crystalline plastic resin used in the inner layer 7 and 30 to 40 parts by weight of a highly soft resin used in the outer layer 9. The outer layer 9, being the part protecting the inner layer 7 and serving mainly to ensure the flexibility of the balloon 1, is made of a material softer than the inner layer 7 and the intermediate layer 8, e.g., low density polyethylene.