Blown Film Bubble Collapsing Improvement

The forces exerted on the blown film bubble during the collapsing process are not uniformly distributed around the bubble. Standard collapsing geometry and the fric tional drag coefficient can be modified to improve this force distribution and reduce the force level. The net result to the film product is better flatness, even distribution of film mechanical properties, and improved thickness uniformity. Furthermore, it provides a film which greatly reduces the wrinkles and distortions which frequently occur when printing and laminating film.