Patent Application
20050048232
Not applicable.
Not applicable.
Many types of bags exist for containing a wide variety of materials. Bags vary size, construction material, appearance, thickness of the bag walls and intended purpose. Bags can be thought of as containers for storing materials or for other purposes such as for cooking food. Most bags intended for storing products typically are formed of multiple plies of paper or other material to achieve a thickness that is appropriate and suited to the intended use. When multiple plies are utilized in the construction of a bag, the plies are generally laminated together to for a multi-wall construction.
One example of a bag is a pet food bag. Some prior art pet food bags are constructed with a metalized paper ply on the exterior of the bag to provide a more pleasing appearance for colorful prints that are applied to the exterior of the bag. When pet food, which contains a certain amount of grease, is placed in these bags it is usually the case that the grease will bleed through the multiple plies of the bag and stain the exterior of the bag. This effect distorts, and in some cases destroys, the appearance of any prints on the bag.
These prior art bags all manifested a nagging problem. Specifically, the bags all allowed the grease from the pet food to stain through to the outer printed layer, which created appearance problems with the bags. In order to address this problem, some bag manufacturers introduced a fluorocarbon-based material to provide grease resistance. These prior art pet food bags are constructed with a clay-coated, bleached craft paper ply that has a fluorocarbon material added into the base sheet of the paper ply to serve as the grease repellant. In these and other types of bags, there is an intermediate natural craft ply and a polyethylene ply. However, this also presented another set of problems because fluorocarbons allegedly create a health hazard and, therefore, their use is not desirable.
In light of this, there exists a need to eliminate the use of fluorocarbons from the construction of bags, while also providing a solution that prevents grease in the contents of the bag from altering the aesthetic appearance of the bag. To this end, it is desirable to have an optimal layer of material that will produce a brightness that is equivalent or better than prior art paper ply. Importantly, when the paper layer between the plastic ply and the outer ply of a bag becomes saturated with oil and becomes stained, the stain should not be visible through the visible outer lamination layer.
The present invention provides a laminated bag having a multi-ply structure and stain hiding abilities that prevents grease from bleeding through to the outer portion of the bag. More particularly, the present invention provides the construction of the bag and materials from which the bag is made.
In one aspect, the present invention provides a multi-ply structured bag comprising an outer lamination ply, an intermediate paper ply and an inside ply, with the outer lamination ply being constructed by lamination of a clear film layer, a co-extruded polyethylene layer and a paper layer.
In another aspect, the present invention provides a white and gray pigmented, co-extruded polyethylene layer that provides grease-hiding characteristics to a bag constructed in accordance with the present invention.
In yet another aspect, the present invention provides method of providing a bright outer lamination surface on a pet food bag for accepting ink and lacquers to provide a decorative and pleasing exterior appearance.
In a further aspect, the present invention provides a bag, which provides stain-hiding characteristics, a bright outer appearance and a durable outer layer that will show less wear on the bag.
The present invention is described in detail below with reference to the attached drawing figures, wherein:
The present invention is directed to a multi-ply bag with the ability to hide stains and the construction thereof. More particularly, the present invention is directed to forming and providing a bag with a brightly colored outer appearance. Additionally, the bag eliminates the use of fluorocarbons and prevents grease contained within the content of the bag from bleeding through to the outer printed surface.
In a preferred embodiment of the present invention, a layer of polyethylene is manufactured with a co-extruded layer of a gray-pigmented polyethylene and a white polyethylene. The gray and white polyethylene layer is extruded separately and put together in a single web curtain as they pass through a dye. As would be understood by one skilled in the art, the process is an extrusion lamination process. In other words, for example, the extrusion comes out of the dye at approximately 600 degrees Fahrenheit and is sandwiched between a paper and polyester ply. The extrusion acts as an adhesive for the paper and polyester and also carries the pigmentation, thus providing the stain hiding characteristics of the layer. Having provided a brief overview of the present invention, a more detailed discussion on the construction and components of a bag will follow, with reference to
Referring more specifically to the drawings and turning initially to
As seen more particularly in
In an embodiment of the present invention, the various panels, 12, 14, 15, and 16 of the bag 10 are constructed with a multi-ply structure. As shown in
The construction of outer lamination ply 22 is illustrated in the cross-section view of
The co-extrusion layer 26 is laminated to a twenty-pound basic weight bleached craft paper, which contains no fluorocarbon materials and is illustrated as paper layer 28. According to the method of the present invention, the gray and white co-extrusion layer 26 contacts the bleach craft paper layer 28. The gray and white co-extrusion layer 26 is also in contact with a clear film layer 24, which forms the outer surface of the outer lamination ply 22.
Outer lamination ply 22 may be printed upon, then slit and fabricated in a bag machine in any one of a number of conventional methods. The fabrication of a bag includes the application of various hot melts and adhesive systems, to affix and adjoin the multiple layers of the bag. In an exemplary embodiment of the present invention, the outer lamination ply 22 is laminated in-line with a natural craft ply, shown as intermediate ply 20. Intermediate ply 20 further adjoins an inner lung film, shown as inside ply 18. This construction produces the wall panels of the bag 10 of
In the manufacture of the bag, while the component plies of the bag are made out of separate webs, the webs are all combined together in a continuous web form prior to being cut and glued to form the bag as earlier described.
In use, the bag of the present invention provides stain-arresting characteristics and protects the aesthetic appearance of the exterior of the bag. The gray/white co-extrusion portion 26 of the outer lamination, which is in contact with the bleach craft paper 28, starts to darken as soon as it comes in contact with oil or grease from the bag's content. The paper layer 28 becomes translucent and stains. However, the middle gray/white polyethylene co-extruded layer 26 does not permit the stain to be seen from the exterior of the bag due to its composition and pigmentation.
The bag of the present invention provides numerous other advantages over prior art bags. The film utilized in the construction of the outer laminate ply 22 is well adapted, to accepting ink and adhesives that are traditionally used on the exterior of bags, to enhance appearance and convey information. The coating and surface tension of the film also allows for the ease of printing and fabrication. Another advantage of the present invention lies in the whiter, brighter appearance of the outer lamination ply 22, i.e. an aesthetic appearance boost. Yet another advantage of the outer lamination ply 22 of the present invention is its ability to withstand the typical wear and tear, and rigors that a bag endures during transportation, distribution and the retail process. In other words, a bag utilizing the outer lamination ply of the present invention has a non-shop worn appearance, i.e. less visible damage to the exterior of the bag. This allows a storeowner to have products that utilize the inventive bags, on the shelf for a much more extended period. An even further advantage of the present invention is the stain hiding property provided by the outer lamination ply 22.
While particular embodiments of the invention have been illustrated and described in detail herein, it should be understood that various changes and modifications might be made to the invention without departing from the scope and intent of the invention. The embodiments described herein are intended in all respects to be illustrative rather than restrictive. Alternate embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its scope.
From the foregoing it will be seen that this invention is one well adapted to attain all the ends and objects set for above, together with other advantages, which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated and within the scope of the appended claims.
