Apparatus for making biaxially stretched tubular films

摘要

An apparatus for producing biaxially stretched tubular films which enables heating air for stretching to pass uniformly around the circumference of a stretching bubble thereby to effect stabilized operation. Said apparatus comprises 1 a circular hood fitted to the section where a loaded raw film starts stretching and a formed stretching bubble expands to its maximum diameter, 2 holders for a plurality of rolls, which holders are mounted on the lower part of said hood, said rolls being held each on the end of said holders which an elasticity allowing swinging of said rolls only in the direction radial to the central axis of said bubble but resistant to being distorted in the direction of circumference of said stretching bubble, and 3 a flexible and shrinkable cylindrical sheet attached to and along the inside lower surface of said hood, the lower end of said sheet being situated immediately above the roll part of said holders.