Abstract:
A bag is made with a combination of mesh and film on both the front and back sides. For use with automatic filling machines, one side of the bag has a wicket strip with wicket holes to receive the wickets from the filling machines. If pneumatic or vacuum systems are used for bag opening, a fluid impervious assisting strip is bonded to the mesh wall at the bag mouth. A method of making such a bag includes the use of a continuous film web with adjacent continuous mesh webs. A linear seal joins the film web with the mesh webs after which the web is folded so that the free edges overlie each other. A transverse seal followed by a transverse cut results in a finished bag.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to bags in which objects of different sorts are carried and stored, and, more particularly, a bag having sides manufactured from a combination of mesh and film materials. 
   2. Description of the Related Art 
   In recent years, a combination film and mesh bag has been developed, primarily to provide greater strength to bags, which are machine filled. One wall of such bag was preferably a synthetic resin mesh while the other wall was a synthetic resin film, which may or may not have been made of the same material. Typical examples of such prior art may be found in the patents to Fox, U.S. Pat. Nos. 6,024,489; 6,030,120; and 6,190,044. 
   The prior art, such as the bags taught in the Fox patents preferred embodiments, consisted of a bag with a back wall of a mesh fabric and the front wall of a film, generally of the same synthetic resin material. An upper extension of film was provided with wicket holes so that the bag could be supported during automated filling operations. 
   The film wall was folded at the bottom and was bonded to the mesh wall, avoiding the necessity of a seam at the bottom of the bag. The film wall of the bag may have textual as well as decorative graphic material imprinted thereon. 
   The prior art bags are not without their shortcomings. For example, it has been determined that some commodities benefit from storage in bags which are cross-ventilated. The presence of a film wall can restrict cross-ventilation, thereby surrendering some of the benefits of the ventilation provided by the mesh wall. 
   The use of all mesh material for the bag can increase the ventilation. However, the mesh material that is used, is relatively expensive as compared to film. Thus, the use of substantial mesh portions increases the bag&#39;s overall cost. The use of all mesh is also undesirable because it cannot be easily used to print advertisements or other information on it. The ability to add advertising to the film portion of a bag increases the bag&#39;s overall acceptance in the commercial marketplace. 
   It is therefore an object of the present invention to provide a combination film and mesh bag that permits for adequate cross ventilation at an economical price. It is also an object of the present invention to provide a bag with sufficient film and mesh portions that will be acceptable to users. 
   SUMMARY OF THE INVENTION 
   According to a preferred embodiment of the present invention, a bag is fabricated with two walls, each partly mesh and partly film, both made from the same (or substantially the same) synthetic resin composition. The upper portion of each wall is mesh and the lower portion of each wall is a sheet of film that is folded with the free ends each being bonded to an end of the mesh sheets. 
   The sides of the mesh/film combination are bonded together, forming a bag with mesh upper portions and film lower portions with a continuous sheet forming the bottom of the bag. If the bag is to be used with automatic filling machines, a sheet of film is bonded to the top edge of one of the walls of the bag. This top sheet is provided with wicket holes. If pneumatic or vacuum assistance is utilized to open the bag, a further film strip can be bonded to the opposite mesh wall. 
   In a preferred embodiment, the film portion of the walls is in a “j-fold” configuration in which the mesh portion of the front wall is somewhat shorter than the mesh portion of the back wall, thereby providing a greater graphic display area on the front, predominantly film wall. 
   In alternative embodiments, the film portions of the front and back wall can be substantially equal, providing equal graphic areas on both walls and substantially equal strength to applied stresses. In yet another alternative embodiment, a bag is formed by sealing a combination of film and mesh sheets along three edges. However, the presence of a seam along the bottom of the bag could be considered a weakness and might limit such a bag to articles of relatively light weight. 
   The novel features which are characteristic of the invention, both as to structure and method of operation thereof, together with further objects and advantages thereof, will be understood from the following description, considered in connection with the accompanying drawings, in which the preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only, and they are not intended as a definition of the limits of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front perspective view of a bag adapted for automatic filling machines. 
       FIG. 2  is a side section view of the bag of  FIG. 1 . 
       FIG. 3  is a side section view of an upper edge of a mesh bag wall with an adjacent film strip. 
       FIG. 4  is a side section view of an alternative embodiment of a bag of the present invention adapted for use with automatic filling machines using pneumatic or vacuum opening assistance. 
       FIG. 5  is a side section view of an alternative embodiment of the bag of the present invention. 
       FIG. 6  is a side section view of the bottom portion of the bag of  FIG. 1  with an item of produce. 
       FIG. 7  is a front perspective view of yet another alternative embodiment of a bag according to the present invention with seals at the sides and the bottom of the bag. 
       FIG. 8  is a side perspective view of the alternative embodiment of a bag according to the present invention depicted in  FIG. 7 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A bag having film and mesh portions will be described. In the following description, various structural details, manufacturing methods and compounds will be described in order to give a more thorough understanding of the present invention. It will be apparent to those of skill in the art that the present invention may be practiced without these specific details. In other instances, well-known processes and structures are not specifically described so as not to obscure the present invention unnecessarily. 
   Referring first to  FIG. 1 , a perspective view of the preferred embodiment of the bag  10  of the present invention is shown. Such a bag is useful for the storage of perishable commodities where cross ventilation is an asset. The front wall  41  and back wall  42  of the bag  10  are manufactured partially from synthetic plastic mesh and film materials. (These film materials are sometimes refered to as “webs”). The bag  10  has primarily a synthetic plastic mesh material  22  as the upper portion and a bottom portion  43  of a synthetic plastic film material  24 . 
   In the preferred embodiments, the mesh and film are of the same (or substantially the same) material, a polyethylene plastic, which facilitates the bonding of the film material  24  to the mesh material  22 . The front and back walls of the bag  10  are sealed together along the vertical edges  26 . In the preferred embodiment, the bottom of the bag results from a folding of the film material  24 , which constitutes the lower section of the bag  10 .  FIG. 2  illustrates a cross-sectional side view of the bag. As can be seen, the folded film results in a bottom portion of the front wall, and a bottom portion of the back wall. 
   In an embodiment of the bag  10  intended for use with automated filling machines, there is, bonded to the upper edge of one side  14  of the bag  10 , a strip of film  16  with wicket holes  18  adapted fit upon wicket pins of commercially available bag-filling machines. A slit  20  is provided above each of the wicket holes  18  to facilitate easy removal of filled bags  10  from the machine. 
   It has been found that best results are achieved if the composition of the plastic material from which the mesh and film is created ranges from 20% to 40% prime polyethylene, 30% to 50% hexene polyethylene with slip, 0% to 6% colorant with the remainder being hexene polyethylene. The raw materials are available from several sources including Eastman, Dow and Chevron, to name a few. 
   Although the preferred embodiment utilizes mesh and film materials of the same chemical composition, it will be understood by those of skill in the art that exact identity of the composition of the two materials is not necessary. The film and mesh portions of the bag can be manufactured from materials having similar, although not identical composition. For example, the film and mesh materials may have chemical compositions that are within the ranges specified above, but of non-identical formulation. 
   Referring again to  FIGS. 1 and 2 , it is shown that the film and mesh portions in the preferred embodiment of the bag have differing vertical lengths. The vertical length is measured from the bottom of the film or mesh portion to its top edge. Generally, the front and back sides of the bag will have lengths which are approximately equal. The film portions on the front and back walls can also have different lengths from each other, as can the mesh portions. 
     FIGS. 1 and 2  illustrate the preferred embodiment of the bag. The mesh material  22  forms the upper portions of the front and back sides. The film material  24  forms the lower portions and the bottom. The bag is manufactured primarily of mesh, and film portion on the front of the bag has a greater vertical length than the film portion on the rear. 
   It will be apparent to those of skill in the art, however, that this arrangement of materials can be changed if desired without departing from the scope of the invention. For example, the bag can be manufactured with the mesh portion on the bottom, and the film on top. The ratio of the lengths of the film and mesh portions can also be varied. It is also not necessary that the front side of the bag be identical to the back side. In an alternative embodiment of the invention, the front side of the bag may have a small amount of mesh and a large amount of film, while the proportions of the two materials on the back side are reversed. The bag can also be constructed so that the film and mesh portions all have substantially equal lengths. 
   In producing such a bag  10 , a continuous process includes the use of two rolls of mesh material, separated by a roll of film material. The edges of the film that is drawn from the film roll is bonded to the edges of the adjacent mesh fabric being drawn from the adjacent mesh rolls. After bonding, the continuous sheet is folded. 
   At predetermined intervals, a transverse seal is made. The seal could be wide or could be a double seal so that a transverse cut will result in two sealed edges. The resulting cut segments are then partially finished bags, to which wicket panels and assist strips could be added. 
     FIGS. 3 and 4  illustrate the application of an assist strip  28  to a mesh side wall  42 . In  FIG. 3 , a space  32  is shown, which exists prior to bonding. In  FIG. 4 , the assist strip  28  is shown bonded to the side wall  42  of the bag  10 . 
     FIG. 5  is a side section view of an alternative embodiment of bag  10 ′ of the present invention. The bag  10 ′ is substantially identical to the bag  10  of  FIG. 1  and, accordingly, similar reference numerals have been applied but with the addition of a prime (“′”). 
   The bag  10 ′ is not intended for use with automated equipment and therefore lacks the wicket strip of bag  10  and the assist strip  28 . The bag  10 ′ includes the two mesh sides  41 ′ and  42 ′ and the film bottom portion  43 ′. 
   Turning now to  FIG. 6 , there is shown the bottom film portion  43  of a bag  10  according to the present invention with an item or article of produce  38  resting therein. As can be seen in this embodiment, there is no bottom seam that will be stressed by the weight of the contents of the bag. 
     FIG. 7  shows yet another alternative embodiment of the bag  10 ″ of the present invention. The principal difference between the bag  10 ″ of  FIG. 7  and the other embodiments is that there is a seal or bond  40  on three sides of the bag, leaving an opening at the top of the bag. As shown, there is a seal  40  joining the mesh to the film in the front and back walls, a seal  40  bonding the front and back side walls together and a seal  40  bonding the film of the front and back walls at the bottom. 
   Other alternative embodiments of the bag of the present invention can utilize different synthetic resin film and mesh materials and may even use a combination of one resin for the film and another for the mesh. By way of example, the mesh and film may be manufactured from a polypropylene based plastic. 
   Turning finally to  FIG. 8 , there is shown still another alternative embodiment of the bag  10 ′″. The bag  10 ′″ is in all respects similar to the bag  10 ′ of  FIG. 5  except that in this embodiment, the mesh portions  22 ′″ are shorter than the film portions  24 ′″. The other elements of the bag  10 ′″ that are similar to corresponding elements of the bag  10 ′ have been given similar reference numerals with a triple prime (′″). 
   Yet other embodiments could combine fabric or paper materials with synthetic plastic materials to form a bag. Alternatively, the bag could be a combination of different materials. It is clear that such bags are not limited to produce but can be used to hold and transport virtually any product which could benefit from the combination of film and mesh in the front and back walls. 
   The feature common to the embodiments is the use of a mesh for at least part of the front and rear walls and the use of a sheet or film material for the remainder of the front and rear walls. While the preferred embodiments would have the sheet or film material as single sheet with opposite ends bonded to the front and back wall mesh sections, respectively, the bottom of the bag could be finished with a seam, bonding the composite back wall to the composite front wall. 
   The present invention is also not limited by the manner in which the front and back walls are bonded together. The preferred embodiment uses heat to bond the front and back walls together, as well as the film and mesh portions of each wall. In this embodiment the homogeneity of the film and mesh means that they will both melt at the same, or similar, temperature, thereby facilitating the bonding process. 
   It will be apparent to those of skill in the art that different means of bonding the elements of the bag together can be used. For example, the front and back walls could be held together by glue or stitching. The film and mesh portions could also be extruded as a single unit in the manufacturing process. Any suitable means of joining the parts of the bag together can be used with equal effectiveness. 
   Similarly, wicket tops and assistance strips can be provided to any bag made according to the present invention including bags of fabric and paper mesh film combinations. Accordingly, the invention should be limited only by the scope of the claims appended hereto.