Abstract:
A package having a dual seal designed to permit venting of the package during microwave heating or cooking while minimizing the possibility for a messy and inadvertent escape of product onto, for example, the floor and walls of the microwave. The seal system sets up a tortuous path for vapors and any splatter from food products, particularly liquid food products, to travel during venting.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to packaging article, more particularly a stand up pouch for microwaving food products, particularly liquid food products, in the package. 
       BACKGROUND OF THE INVENTION 
       [0002]    The amount of time available for preparation of meals has been steadily diminishing in recent years. Microwave cooking has been embraced by many consumers as one solution to the problem of dwindling meal preparation time. Microwave cooking often demands less attention than conventional oven cooking and is usually completed in a shorter period of time. 
         [0003]    But it is not enough merely to shorten the amount of time which must be devoted to cooking. For instance, consumers would also prefer not to have to expend effort washing or cleaning the microwave at the completion of microwave cooking, to the extent that this can be avoided. There is a need, therefore, for microwave packaging which can meet a variety of consumer desiderata, including easy opening and minimization of time spent cleaning the microwave. 
         [0004]    Numerous microwavable containers have been disclosed over the years. 
         [0005]    Johnson et al. EP 823 388 (Kraft) discloses a stand up pouch for a microwavable food entrée. Notch  23  may be included to facilitate initiation of the opening procedure. Hughes et al., U.S. Published Patent Application No. US2004/0118839 relates to a stand up pouch that is a convenient vehicle to eating, which uses a single partial tear for venting. Igota et al U.S. Pat. No. 6,121,597 discloses a notched bag for microwave ovens capable of allowing escape of vapor generated during microwave heating using joints of different weaknesses. 
         [0006]    Chow et al. US Published Patent Application No 2002/0068668 discloses a method for producing an easy open, easy tear package using a laser. A microprocessor modulates the laser to create tear initiation areas along a score line. 
         [0007]    Tang US Published Patent Application No. 2002/0001645 is directed in  FIG. 12  to a package made from an ACE sheet and an inner layer. The ACE sheet has nicks on each of two lines of weakness to permit sequential opening of three compartments. In the embodiment of  FIG. 9   j,  prior to microwave cooking, the consumer tears the bag open along lines of weakness  34  to create a small opening allowing partial release of gas vapor during cooking. Following microwave cooking, the bag may be opened using further aligned lines of weakness  45 . The further aligned lines of weakness  45  may extend substantially parallel to the lines  34 , no greater than 15 mm apart. 
         [0008]    None of the references create a tortuous path for venting as a means of guarding against splatter in the microwave, thereby being particularly useful for microwave heating liquid food products. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention is directed to a new microwavable package having a seal so configured as avoid splatter of the product during heating or cooking in the microwave, thereby avoiding the need for the microwave to be washed after heating or cooking. The package is designed to permit venting of the package during cooking while minimizing the possibility for a messy and inadvertent escape of product onto, for example, the floor and walls of the microwave. The seal system sets up a tortuous path for vapors from food products, particular liquid food products, to travel during venting. 
         [0010]    The package comprises a bottom end and a top end and first and second side wall ends extending between the bottom and top ends. A top seal is provided along the entire top end to seal the package for storage of a food product. A splatter guard seal is situated a sufficient distance below the top end, spanning from the first side wall end approximately half way along and parallel to the top end. A tear area is provided which instructs cutting of at least a portion of the top end and of the first side wall. Removal of a portion of the top end along the tear area assists cooking of the package contents by permitting release of pressure accumulated within the package due to elevated temperatures. However, after the original top end is torn off, the splatter guard seal creates a tortuous path between the opening at the torn top end and the food contained within the package such that the chances of spattering of the product during cooking are essentially eliminated. The second partial seal, i.e., the splatter guard, prevents liquid food from splattering during microwave cooking. 
         [0011]    Since a purpose of the dual seal is to permit the food to be cooked without splattering into the microwave, there will generally be a vertical distance between the seals, preferably about one inch, especially at least about 0.25 inch, and at most about one and one half inches when the height of the pouch is about 6 to about 7 inches. The important thing is that the dual seals have an adequate vertical distance between them and that their configuration creates a tortuous path, so that the goal venting without spilling is achieved. 
         [0012]    Optionally, but preferably, a label or graphics are provided on the pouch to indicate to the consumer where the pouch should be cut prior to cooking. 
         [0013]    The pouches may be sealed using a variety of techniques known in the art, including for example by way of laser sealer or ultrasonic sealer. 
         [0014]    Preferably, the package is a microwavable stand up pouch which, when food is contained therein, can be rested on the bottom end on a tabletop or other flat surface with the opening at the top. Typically the package will be a flexible package comprised of a microwavable material, preferably lamination containing polyethylene, polypropylene, polyester and/or nylon. 
         [0015]    For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments and the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0016]      FIG. 1  is a cross sectional view of a pouch, after sealing, according to the present invention; 
           [0017]      FIG. 2  is a perspective view of the pouch of  FIG. 1  filled with food product. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The package of the invention will generally be made of flexible packaging, e.g., thermoplastic, and will typically take the form of a bag or pouch. The package material may, for instance, be a reverse printed multi-layer lamination such as one comprising a layer of polyester and a layer of polypropylene. 
         [0019]    With reference to  FIG. 1 , pouch  10  is prepared by placing two layers of the packaging lamination one atop the other, or folding a single layer, and sealing along the sides to provide first side wall end  12  and an opposing second side wall end  14  and side sealing margins  31 ,  32 , respectively, and along the bottom end  34  to provide bottom sealing margin  24 . Sealing may be effected, for example, by heat sealing, using laser or ultrasonic techniques for example. 
         [0020]    Areas of sealing prior to filling of the pouch are along these margins, leaving top end  30  open. Sealing margins  31 ,  32  may have a variety of cross sectional shapes, e.g., rectangular, triangular, circular, oval, etc. 
         [0021]    Bottom end  34  is preferably provided with a gusset or other arrangement (not shown) at bottom end  34  to promote standing up of the pouch when it is filled with food, as is known in the art. In this way, once the package has been filled, it can be rested by means of bottom end  34 . 
         [0022]    Prior to filling, pouch  10  is typically open only at top end  30  for filling, followed by sealing with the dual sealer according to the present invention. After pouch  10  is filled with microwavable food product  26 , it is sealed continuously along the upper edges of the sheets at upper end  30  of the pouch to form upper seal  18 . A second seal, splatter guard seal  20  is provided an effective distance, preferably about 1 inch, below upper seal  18 , running parallel to seal  18  from first side wall  12  but only partially along the width of the pouch. Preferably, splatter guard seal  20  spans about 0.50 the width of the package or less, such as about 0.25 to about 0.75 the width of the package. 
         [0023]    Side sealing margin  31  is on side  12  has an end of the pouch which is to be cut open prior to microwave heating, referred to as tear area  22 . Optionally, but preferably, a label or graphics (not shown) are provided on pouch  10  to indicate to the consumer where pouch  10  should be cut prior to cooking. The label or graphics denote tear area  22  which promotes cutting of only a portion of top wall  30  of pouch  10  to create opening  23  for venting and subsequently for dispensing liquid food product. Cutting may be along a single line to remove a substantially triangular section, as shown in  FIG. 2 , or along two substantially perpendicular lines to remove a substantially rectangular area, as denoted by dotted lines in  FIG. 1 . 
         [0024]    In use, when ready to microwave the product, a consumer cuts the pouch along tear area  22 , removing only a portion of top end  30  of pouch  10  to create opening  23 . Opening  23  permits pouch  10  to vent while it is being microwaved. However, after the original top end is torn off, the splatter guard seal  20  creates a tortuous path  28  (shown by the arrow in  FIG. 2 ) between the opening at the torn top end and the food contained within the package such that the chances of spattering of the product during cooking are essentially eliminated. The tortuous path for venting vapors, indicated with an arrow in  FIG. 1 . When cooking is completed, the pouch is removed from the microwave and then the food product is allowed to be fed by gravity to exit from pouch  10  through opening  23 . 
         [0025]    Suitable microwave ovens will typically operate at powers of about 800 Watts to about 1200 Watts. 
         [0026]    Although not limited by size, preferred pouches according to the present invention will hold about 5 weight oz to about 15 weight oz of product, with most preferred capacities being 8 oz and 13.5 oz weight sizes. Although not limited by fill methods, preferably, product is filled to about 0.75 of the full volume capacity of the pouches. 
       EXAMPLES 
     Example 1 
       [0027]    For all the examples, a 1000 W microwave was used. Pouches were filled to about 0.75 of full capacity. 
         [0028]    Pouch  10  according to the present invention was filled with product, sealed with top seal  18  and splatter guard seal  20 . Pouch  10  was then cut upon along tear area  22  and heated with product inside in a microwave on high for 90 seconds. No splatter was observed. 
       Example A 
       [0029]    A pouch having the same dimensions as that of Example 1 was provided, except that the splatter guard seal was not used. The pouch was then cut upon along a tear area as in Example 1. When heated in the same microwave with the same amount of the same product, food splattered onto the microwave floor and/or walls within about 90 seconds of heating on high. 
       Example B 
       [0030]    A pouch having the same dimensions as that of Example 1 was provided, except that the splatter guard seal was not used and the pouch was cut along the entire width of the top end. When heated in the same microwave with the same amount of the same product, food splattered onto the microwave floor and/or walls within about 90 seconds of heating on high. 
         [0031]    Example 1 and comparative Examples A and B demonstrate how essential the splatter guard is for avoiding soiling of the microwave. 
         [0032]    The term “comprising” is used herein in its ordinary meaning and means including, made up of, composed of, consisting and/or consisting essentially of. In other words, the term is defined as not being exhaustive of the steps, components, ingredients, or features to which it refers. 
         [0033]    Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts or ratios of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word “about”. 
         [0034]    It should be understood, of course, that the specific forms of the invention Is herein illustrated and described are intended to be representative only as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.