Patent ID: 9120267
Filing Date: 2015-09-01
Classification: B29C

Abstract:
1. A process of supplying a thermoplastic polymer film having longitudinally extending pleats comprising: stretching the advancing film in the solid state in one or more short zones between or on two or more stretching rollers or partly on and partly between such rollers, and entwining the advancing film in the solid state under longitudinal tension around a grooved mini-roller having corrugations and stretching on a smooth stretching roller, where the mini-roller is mounted upstream of and in close proximity to the smooth stretching roller, where the mini-roller is characterized by having: a) a pitch of the corrugations of 20 mm or less; as measured from a middle of a tip to a middle of each neighboring tip; b) a ratio of a perimeter to the pitch ranging between 1.10 and 1.80, where the perimeter is measured from a middle of a tip to a middle of each neighboring tip along the corrugated roller surface; and c) a diameter of less than or equal to 4 times the pitch, where a width of the film as measured in a straight line from edge to edge is reduced after the stretching and entwining to form a film having a pattern of longitudinally extending pleats.