Balloon and manufacture thereof

Process for forming a high molecular weight, biaxially oriented, flexible polymeric balloon, the process comprising, at a temperature within the range extending from the second order transition temperature to the first order transition temperature, drawing a polymeric tubing having a finite length (L.sub.1) and an internal diameter (ID) which is about one-half the outer diameter (OD) to a length (L.sub.2) which is 3 to 6 L.sub.1, and thereafter expanding the drawn tubing of internal diameter ID.sub.1 and outer diameter OD.sub.1 by expanding means to an internal diameter (ID.sub.2) which is 6 to 8 ID and an outer diameter (OD.sub.2) which is about 3 to 4 OD, following by cooling the drawn and expanded tubing to less than its second order transition temperature, said balloon thus formed having a burst pressure of at least 200 psi (1.4 MPa) and a radial expansion beyond nominal inflated diameter of less than 5% at 200 psi (1.4 MPa).

Process for forming a high molecular weight, biaxially oriented, flexible polymeric balloon having a wall tensile strength of at least 31,714 psi (218.86 MPA), the process comprising, at a temperature within the range extending from the second order transition temperature to the first order transition temperature, drawing a polymeric tubing having a finite length (L.sub.1) and an internal diameter (ID) to a length (L.sub.2) which is 3 to 6 L.sub.1, and thereafter expanding the drawn tubing of internal diameter (ID.sub.1) and outer diameter (OD.sub.1) by expanding means to an internal diameter (ID.sub.2) which is 6 to 8 ID, followed by cooling the drawn and expanded tubing to less than its second order transition temperature.