High strength ribbon-woven disposable bag for containing refuse

This is a continuation of co-pending patent application Ser. No. 11/079,060 filed Mar. 14, 2005 entitled High Strength Ribbon-Woven Disposable Bag For Containing Refuse, the contents of which are incorporated herein by reference.

This invention relates to disposable bags and more particularly to a polypropylene ribbon-woven bag of sufficient strength to contain heavy refuse having pointed or sharp edges without rupture, tearing or disintegration.

Disposable refuse bags have typically involved the use of 3-mil polyethylene films which are formed into bags and provided on rolls for use in the containment or collection of lightweight refuse, preferably refuse which does not have any sharp edges, points or other protuberances which could cause the bag to rip or tear. Moreover, such bags are limited in the weight of the contents to normally 20 to 25 pounds, which means that a large majority of the bag is unfilled and therefore unused.

When such bags are used on construction sites for containing, for instance, bricks, drywall pieces, two-by-fours with our without nails protruding therefrom, slate, tree limbs, cable, masonry, shingles, insulation, pipe, wire, gravel, metal or glass shards, typically these bags fail by either stretching and rupture due to the weight of the contents within the bag when the bag is lifted; or due to the puncturing, slicing or piercing of the bag film which has very little shear resistance. In such cases that the puncture or hole produced propagates rapidly to cause the contents of the bags to spill out through the rip or unintended opening of the bag.

Typically for construction sites, in the past, rubberized barrels were utilized to contain the refuse that existed at the site. However, these barrels are both expensive and are subject to theft. Moreover, the barrels themselves take up a considerable amount of space and are relatively heavy in and of themselves. The amount of rubber necessary to form such barrels causes such barrels to weigh, for instance, ten pounds without being filled. Also, these barrels, due to their cost, are not throwaway items and must be stored when not in use.

Though the barrels themselves may be nested to reduce the amount of storage space, when these barrels are nested they oftentimes stick to each other and are difficult to dislodge.

The result for one cleaning up a jobsite is either to use the expensive, large barrels or to utilize polyethylene continuous film bags, both of which are unsatisfactory for the above reasons.

Rather than utilizing non-throwaway barrels and rather than utilizing film bags, in the subject invention a high strength bag suitable for carting away demolition products such as bricks, wood, nails, and glass is comprised of a woven ribbon structure in which the woven material, rather than being a cord or strand, is a ribbon of polypropylene.

It has been found that, when bags are constructed utilizing the woven ribbon structure, the bags will safely contain refuse weighing in excess of 125 pounds for 40″×29″ bags. It has also been found that any piercing of the woven structure does not creep or otherwise travel due to the woven nature of the bag, making the bag both tear resistant and cut resistant, while at the same time providing a tear strength or modulus which is quite high and in one embodiment is 35 warp pounds or 32 filling pounds according to ASTM 5587.

While such a ribbon-woven structure does in fact stretch, it has been found that the bag does not rupture with loading so that the bag may be utilized to contain large amounts of refuse without fear of the bag breaking or failing.

In one embodiment, the bag is made by melting polypropylene pellets, extruding a web that is relatively flat, and then cutting the web longitudinally to make ribbons. These ribbons are then wound up on spools, with the spooled ribbons then feeding a loom or weaving machine such that an under/over weave is produced in which the flat ribbons are clearly visible to the naked eye.

In one embodiment, the polypropylene ribbons are three to six millimeters wide, a millimeter thick and are woven in an over and under pattern having a stitch count of 100 per inch.

While the weave can be made tight enough to prevent small objects from exiting the bag, in one embodiment a liquid-tight bag is provided by laminating a polypropylene film to the outer surfaces of the ribbon-woven bag. The polypropylene film is heat sealed to the web in a laminating process involving placing sheets about the exterior of the bag and laminating them to the outer surfaces of the bag through a heat/temperature cycle. Thereafter the bag with the laminate is cooled in a water bath.

In both the laminated and the non-laminated bag configurations, the structure is woven cylindrical, after which it is flattened. In order to manufacture each of the individual bags, the cylindrical flattened structure is severed along a transverse cut line and the bag is folded back on itself at the cut and stitched so as to form the bottom of the bag. The unsevered portion of the bag serves as the top or open portion of the bag.

In one example, bags of 40″×29″ weigh only 85 grams, which make the bags of light enough weight to be folded and packaged in a convenient manner to be opened at the jobsite.

The bags are intended to be throwaway and packaged folded so that there is no problem of having to provide and store bulky containers.

The ASTM ratings of the bag are set forth in the table below: