Patent Publication Number: US-8112974-B1

Title: Microwaveable food package

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of co-pending U.S. patent application Ser. No. 11/615,476, filed Dec. 22, 2006, the entirety of which is incorporated by reference herein. 
    
    
     FIELD 
     The present invention relates broadly to food packaging. Specifically, the present invention relates to microwaveable food packaging that vents while cooking in a microwave oven. 
     BACKGROUND 
     Microwave ovens are present in nearly every kitchen. Supermarkets now sell a vast assortment of microwaveable food products. However, in many microwaveable products, the heat generated inside the food packaging needs to be handled carefully to prevent injury and improper cooking of the food contained within the microwaveable package. 
     Prior approaches to solving this problem are insufficient. Some packaging requires the user to cut open a portion of a plastic pouch. Usually this is only at one end of the package, and done simply to prevent a pressure buildup within the plastic pouch. This does not allow proper airflow in many instances, and in some cases can allow food to spill out of the package during cooking or handling. In another approach, a clip is attached to the pouch after it is opened to close the package yet allow the package to vent, but some users will fail to attach the clip properly, and leakage may still occur. 
     Thus, there still remains a heartfelt need to for a microwaveable food package that incorporates improved venting. 
     SUMMARY 
     The present invention provides a microwaveable food package that incorporates very small perforations made by a laser on portions of a plastic pouch. In an embodiment, these perforations are on opposite sides of one panel of a plastic pouch in a strip pattern. The perforations are quite small and in some cases unnoticeable to the human eye, and do not require the user to slit open the pouch or open any portion of the pouch. In the case of frozen food, the perforations can be oriented on one side of the pouch, so that the pouch can be laid on a plate or other surface inside the microwave oven with the perforations facing up, so that no food leaks out of the pouch as the pouch cooks. One main benefit realized from the present invention is a more uniform venting of the food while it cooks, so that the chance of scalding the user or improperly cooking the food is greatly reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates the formation of apertures in food packaging by a laser; 
         FIG. 2  illustrates an embodiment of aperture configuration in the packaging sheet; and 
         FIG. 3  illustrates an alternative embodiment of aperture configuration in the packaging sheet; and 
         FIG. 4  illustrates Vertical Form-Fill-Seal (VFFS) equipment creating a food package, in accordance with the prior art. 
     
    
    
     DETAILED DESCRIPTION 
     Directing attention to  FIG. 1 , laser  100  is positioned above packaging sheet  102 , which is fed from supply roller  104  to collection roller  106 . Laser beam  108  is directed to packaging sheet  102 , and perforates packaging sheet  102  as it passes beneath laser  100 . In the preferred embodiment, laser  100  is comprised of a Laser Processing Module  100 , available from LasX Industries, Inc., of White Bear Lake, Minn. Laser  100  can be configured to form apertures in a wide variety of patterns on packaging sheet  102 , for example to avoid labeling or packaging graphics, or to intersperse apertures different areas of packaging sheet  102  so they are less noticeable to the human eye, or to meet oxygen flow requirements of the food contained with the food package. In an embodiment, apertures can be formed in columns of apertures running the length of packaging sheet  102  to form a vent. In an embodiment, columns can be spaced two inches apart, or on opposite sides of a seal (such as a lap seal or a fin seal) that often is formed in the center of one panel of a food package. Apertures are formed with a diameter ranging from approximately 100 microns to approximately 800 microns, preferably at 400 microns in diameter. The size of the hole may depend on several different factors, such as the size of the food package, the required oxygen transfer, or aesthetics. 
     Packaging sheet  102  may be polyester, oriented polypropylyn, cast, polypropylyn, nylon, mylar, polyethylene, or other suitable material. Packaging sheet may also comprise several layers of these materials depending on packaging needs, as known to those skilled in the art. 
     Directing attention to  FIG. 2 , a segment of packaging sheet  102  is shown. Packaging sheet  102  contains aperture column  200  and aperture column  202 , which are oriented on opposite sides of seal  204 . Seal  204  is generally formed by affixing two edges of packaging sheet  102 , in either a lap seal or fin seal as described above. By placing columns  200 ,  202  at opposite sides of packaging sheet  102  and sealing ends  206 ,  208 , a sealed food pouch can be formed around a food product to be microwaved, thus providing improved oxygen transfer to the food product as well as a safer food package that poses less threat of scalding a user upon removal from the microwave oven. 
     Directing attention to  FIG. 3 , apertures  300  can be interspersed throughout the packaging sheet  102 , and have the same diameter as described above. 
       FIG. 4  illustrates Vertical Form-Fill-Seal (VFFS) equipment creating a food package, in accordance with the prior art. VFFS equipment  400  are currently utilized to create and fill packages containing a number of different food items, including fresh and frozen vegetables, fresh fruits, potato chips, popcorn, etc. The VFFS equipment  400  comprises a fill funnel  402  for accepting the food item to be packaged attached at the top of a fill tube  401 . The quantity of food to be packaged into a single package will typically be metered before being placed in the fill funnel  402 . Meanwhile, a packaging sheet  410  is fed on a roller  412  to the VFFS equipment  400 . It is wrapped completely around the fill tube  401  located below the fill funnel  402 . Two vertical seams  414  are joined together utilizing, for example, a vertical crimping or sealing unit  404  that applies heat, pressure, or other means to accomplish the joining The result is a long hollow tube with a side seam  416  wrapped around the fill tube  401 . The packaging may then be gusseted by a gusting mechanism  406 . Next, the long hollow tube is sealed at the bottom with a horizontal sealing unit  408 , utilizing, for example, heat and/or pressure to seal the bottom of the long hollow tube. At this point, the food items or other contents are metered and inserted into the fill funnel  402 , travel down the fill tube  401 , into the hollow tube that is sealed on the bottom. Meanwhile, the hollow tube drops down a prescribed distance, and the tube is again sealed with the horizontal sealing unit  408 . The packaging is then complete, except that the packaged food or other items is still attached to the bottom of the hollow tube of packaging material. A cutting unit (not shown), for example utilizing a knife blade, then cuts the packaged food or other items from the hollow tube of packaging material, and the packaging is complete. Note that in this illustration, the vertical sealing unit actually provides two seals, one above the other, at a time, and the cutting unit cuts between the two seals, resulting in an average of one seal per package of food or other items produced, since each the package shares the sealing with the package above and the package below. This is exemplary, and other methods of packaging food products are also within the scope of the present invention. 
     While a microwaveable food package has been described and illustrated in detail, it is to be understood that many changes and modifications can be made to various embodiments of the present invention without departing from the spirit thereof.