Abstract:
Reinforced plastic film comprising a length of plastic film and a reinforcing strip of plastic film integral therewith and extending along the length of the film and spaced from its opposite side edges.

Description:
RELATED APPLICATION  
       [0001]    This application claims priority from U.S. Provisional Patent Application No. 60/293,553 filed May 29, 2001. 
     
    
     
       FIELD OF INVENTION  
         [0002]    This invention relates to reinforced plastic film which is useful (inter alia) for wrapping pelletised loads.  
         BACKGROUND OF THE INVENTION  
         [0003]    It is known to use reinforced plastic film for wrapping pelletised loads, see for example U.S. Pat. No. 5,531,391 (Salzsauler et al) issued Jul. 2, 1996, the contents of which are hereby incorporated herein by reference, which describes plastic film with the two opposite outermost side edges being thicker than the remainder of the film for strengthening the outermost edges of the film. Although such plastic film is satisfactory for various pelletised loads, there still exists a need for improved plastic film.  
         SUMMARY OF INVENTION  
         [0004]    According to the present invention, elongated plastic film is provided with at least one reinforcing strip of plastic film integral therewith and extending along the length of the film and spaced from its opposite side edges. The or each reinforcing strip may be incorporated in the film during manufacture thereof or may be applied thereto after manufacture.  
           [0005]    A particular advantage of the invention is that, if the film is punctured during use, a resultant tear will be stopped from excessive lateral travel by any reinforcing strip which it encounters.  
           [0006]    The plastic film may for example have a thickness in the range of from about 10 to about 100 microns, and each reinforcing strip may have a thickness in the range of from about 10 to about 100 microns. Each reinforcing strip may have a width in the range of from about 0.25 to about 2.5 inches.  
           [0007]    The plastic film and each reinforcing strip may be single or multilayer stretch plastic film of any suitable material and may be of the same or different material. Typically, for pelletising loads, the plastic film may be single layer linear low density polyethylene. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0008]    Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, which:  
         [0009]    [0009]FIG. 1 is a perspective view of a roll of reinforced plastic film in accordance with one embodiment of the invention,  
         [0010]    [0010]FIG. 2 is a similar view to FIG. 1 but showing an initial portion of the film unwound from the roll,  
         [0011]    [0011]FIG. 2A is a sectional view of the film taken along the line  2 A- 2 A of FIG. 2,  
         [0012]    [0012]FIG. 3 is a diagrammatic view showing one method of making a reinforced plastic film in accordance with the invention, and  
         [0013]    [0013]FIG. 4 is a similar view to FIG. 3 but showing another method for making a reinforced plastic film in accordance with the invention.  
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0014]    Referring first to FIGS.  1  to  2  of the drawings, a roll  12  of reinforced plastic film comprises a length of plastic film  14  wound on a cylindrical core  16  which is conventionally made of laminated paperboard. It will be noted that opposite end portions  18 ,  20  of the core  16  project a short distance beyond the edges of the plastic film  14 . In this embodiment of the invention, the plastic film  14  has three laterally spaced longitudinally extending integral reinforcing strips  22  spaced from the opposite side edges of the film  14 . In this embodiment, the reinforcing strips  22  are of the same plastic material and the same thickness as the plastic film  14 .  
         [0015]    When the reinforced plastic film  14  is wound on the core  16 , the reinforcing strips  22  become wound at a slightly lesser diameter than the film  14 , with the result that the reinforcing strips  22  form annular constrictions  24  around the roll  12 .  
         [0016]    The reinforced plastic film  14  is especially suitable for wrapping around pelletised loads, and the projecting end portions  18 ,  20  at the core  16  provide convenient handles for manually holding the roll while the film  14  is being wrapped around a load.  
         [0017]    It will readily be appreciated by a person skilled in the art that the integral reinforcing strips  22  not only reinforce the film  14  but also provide stops for any tears which may occur in the film when in use.  
         [0018]    The film  14  may be provided with reinforcing strips  22  during manufacture or after manufacture in a separate operation. FIG. 3 shows the film  14  and integral reinforcing strips  22  being extruded from a flat die  24  and passing between rollers  26 , 28  before being wound on the core  16 . FIG. 4 shows the reinforcing strips  22  being extruded from a die  30  and passing over a guide roller  32  before passing between rollers  26 ,  28  where they are mated by heat and pressure with a pre-manufactured film  14  being unwound from a roll  34  before winding onto core  16 .  
         [0019]    If desired, the core  16  may be omitted so that the roll  12  is coreless, for example as described in U.S. Pat. No. 6,102,213 (Salzsauler et al) issued Aug. 15, 2000, the contents of which are also hereby incorporated herein by reference.  
         [0020]    Other embodiments of the invention will now be readily apparent to a person skilled in the art, the scope of the invention being defined in the appended claims.