TUBULAR INSULATING CURTAIN AND METHOD OF MANUFACTURE

A set of selectively collapsible and expandable insulating curtains and the method of making same, the curtains each having a plurality of collapsible tubes, preferably of plastic material, extending longitudinally across the width and superimposed one on top of the other in a row in the direction of curtain height. Each tube has an upper wall and a lower wall secured together by bands of adhering contact on opposite sides of the tubular cavity. Additional bands of adhering contact secure superimposed tubes to each other longitudinally along midsections of the upper and lower walls. The side bands of contact define fold lines allowing collapse and expansion of the tubes as the curtain is raised and lowered, respectively, in the manner of a venetian blind. Each curtain may include additional rows of superimposed tubes one adjacent to the other in the direction of curtain thickness. In making the curtains, a plurality of thin-film layers are wound about the periphery of a forming member with bands of adhering material interlaminated between adjacent strips, the width of the midsection bands corresponding to the desired width of the expanded tubes and bands between successive adjoining layers being in a staggered relationship. After winding is complete, the superimposed layers are cut transversely, removed from the forming member and straightened to form a curtain. The number of spaced bands may be such that the layers may also be cut longitudinally to provide a plurality of curtains. After straightening, means may be secured to the tubular structure for hanging and selectively collapsing and expanding the curtains.