This invention generally relates to methods and systems for forming a packing material. More specifically, the present invention relates to methods and systems for making a multitude of small, thin, closely-spaced slits in a flat paper or paper like material that allow that material to be expanded into a three-dimensional shape or form in which the paper material may be used as a cushioning or filler material.
Cushioning or filler materials are often used to protect articles that are being shipped or transported. For instance, an article may be wrapped in a cushioning material and then placed in an envelope or box for shipment. Alternatively, an article inside a box or package may be surrounded with cushioning or filler material to cushion the article during transportation.
Conventional packing materials have several important disadvantages. For example, small, peanut-shaped styrofoam articles and flat plastic sheets impregnated with a multitude of bubbles, referred to as bubble wrap, are commonly used as packing materials. Toxic wastes are produced, however, when these materials are made. In addition, the disposal of these packing materials has become a significant environmental problem. In particular, these materials are not biodegradable; and, at the same time, these packing materials, particularly the styrofoam peanuts, are bulky and it is not generally feasible to store these items for reuse. Crumpled newspapers may also be used as a packing material, however, newspapers are often not very effective for this purpose.
Recently, attention has been directed to using expandable paper as a packing material. To form such a packing material, a flat, thin sheet of paper, or paper-like material, is provided with a multitude of rows of small, closely-spaced slits. The slits in adjacent rows are staggered so that the slits in one row extend across the spaces between the slits in an adjacent row. After the slits are formed in the paper, the ends of the paper are pulled apart, and this pulls the paper into a three-dimensional shape comprised of a multitude of six-sided cells. In the direction perpendicular to the original plane of the paper, the expanded paper material is both load-bearing and resilient, and the paper, hence, makes a very good cushioning or packing material. For instance, the expanded paper can be wrapped around an article to protect that article during shipment, or the expanded paper can be placed in a box or container, under and around another article, to cushion that article.
It has been found that, in order for the paper to expand properly, it is necessary that virtually every slit must be cut completely through the paper over substantially the entire length of the slit. Typically, though, such thorough or complete cutting is not obtained with prior art high speed, automated die cutting or stamping processes; and, instead, with these prior art processes, numerous small connections remain across a cut or slit. These small connections prevent a paper, having a multitude of rows of slits as discussed above, from expanding into the desired uniform, three-dimensional shape that is needed to achieve the necessary combination of flexibility and load bearing strength.