Flexible films, particularly those made of comparatively inexpensive polymeric materials, have been widely employed for the protection and preservation and containment of various items and materials. Additionally, web materials having modified properties to provide a desired resistive force to an applied elongation force on the web are generally known. Such web materials are described in U.S. Pat. Nos. 5,518,801; 6,394,651; and 6,394,652.
The term “flexible” is utilized herein to refer to materials that are capable of being flexed or bent especially repeatedly such that they are pliant and yieldable in response to externally applied forces. Accordingly, “flexible” is substantially opposite in meaning to terms “inflexible,” “rigid,” or “unyielding.” Materials and structures that are flexible therefore may be altered in shape and structure to accommodate external forces and to conform to the shape of objects brought into contact with them without losing their integrity. Flexible films of the type commonly available are typically formed from materials having consistent physical properties throughout the film structure, such as stretch, tensile, and/or elongation properties.
Flexible film webs that have deformations formed in them are known. A known method for forming such films is by passing a continuous web between a pair of matched forming rollers to form an intentional pattern of deformations on the film. Illustrative of the state of the art with regard to such continuous webs and film materials having intentional patterns of deformations formed therein are described in U.S. Pat. Nos. 5,554,093; 5,575,747; 5,723,087; and 6,394,652. Accordingly, an object of the present invention is to provide web materials that exhibit differential elastic-like behavior in the direction of applied elongation without the use of added materials. As used herein, the term “elastic-like” describes the behavior of web materials that, when subjected to an applied elongation, the web materials extend in the direction of applied elongation. When the applied elongation is released, the web materials return to a substantial degree to their untensioned condition. While such web materials exhibiting an elastic-like behavior have a wide range of utility (for example, durable articles of apparel, disposable articles of apparel, covering materials such as upholstery, wrapping materials for complex shapes, and the like), they are particularly well suited for use as top sheets, back sheets, absorbent cores, and absorbent articles and for materials suitable for the containment of matter.