Abstract:
A disposable cover for use in a microwave for covering food with or without food vessels. The cover is flexible and may be folded flat for storage. When unfolded, the cover forms a three-dimensional structure that is self-supporting. The cover may include an optional window.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention generally relates to field a dish and food covers, and more particularly relates to a disposable article for covering dishes and food during microwave cooking. 
         [0002]    When food is heated in a microwave, water molecules within the food become excited resulting in a buildup of pressure. This pressure escapes from food in the form of steam. Frequently, the release of steam is sudden, like an eruption, which causes food to splatter. Therefore, whenever food is heated in a microwave, it should be covered to prevent splattering food particles from soiling the interior of the microwave. 
         [0003]    Existing disposable food covers do not provide consumers with convenient, easy-to-use covers for microwave cooking. For example, wax paper absorbs much of the moisture produced by cooking and becomes quite soggy and difficult to handle after heating the food. Like wax paper, paper towels tend to droop into the food and absorb too much moisture from the food. Further, paper towels may stick to the food. Both wax paper and paper towels can easily fall off the food, especially when there is a turn-table in the microwave. Plastic films may be used to cover food for microwave heating, however, because of the potential concern that chemical contamination can occur, it is recommended by some consumer and environmental groups that such films do not touch the food. This can be a difficult recommendation to follow, because when heated food starts to cool a vacuum may be formed which pulls the plastic film into contact with the food. In addition, any steam that builds up under the plastic can be quite dangerous. Steam burns may occur if a person lifts up a plastic film that has not been properly vented during cooking. 
         [0004]    Existing disposable food covers seem to have little effect in preventing hot spots from occurring during the heating process. For example, using plastic film to cover food for reheating can cause certain parts of the food to become overcooked or tough. 
         [0005]    Accordingly, there exists a need for overcoming the disadvantages of the prior art as described above. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention is an article for covering a body of food for microwave heating. The article is made from a flexible sheet defining an outer surface and an opposite food-facing surface, and a top portion and a side portion, wherein the side portion comprises a plurality of panels permanently attached together to form seams. The top portion lies in an intersecting plane with respect to the side portion, and is elevated above a plane by the side portions to create a volume. 
         [0007]    In another aspect of the invention there is a method of manufacturing a three-dimensional article for covering a body of food for microwave heating having the steps of: 
         [0008]    forming a blank from a sheet of material by creating an overall shape; 
         [0009]    placing a plurality of notches in the blank that extend from an outer edge toward a center point, each of the plurality of notches defined by a pair of inner edges converging into a corresponding apex; permanently attaching each pair of inner edges together to form seams, wherein each of the seams extend from the outer edge to the corresponding apex; 
         [0010]    wherein the step of permanently attaching each pair of inner edges creates the three-dimensional article having a volume by creating a top portion and a side portion. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The accompanying figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
           [0012]      FIG. 1  is a front elevated cross-sectional view of a heated dish within a microwave covered by one embodiment of the anti-splatter cover of the present invention. 
           [0013]      FIG. 2  is a plan view of a blank used to create one embodiment of the anti-splatter cover of the present invention. 
           [0014]      FIG. 2A  is a cross-sectional view of a seam between panels on any of the embodiments of the present invention. 
           [0015]      FIG. 3  is a front elevated cross-sectional view of a heated dish covered by the anti-splatter cover of  FIGS. 1 and 2 . 
           [0016]      FIG. 4  is a front perspective view of a heated dish within a microwave covered by another embodiment of the anti-splatter cover of the present invention, this embodiment having a translucent window. 
           [0017]      FIG. 5  is a plan view of a blank used to create the embodiment of the anti-splatter cover shown in  FIG. 4 . 
           [0018]      FIG. 6 . is a plan view of a blank used to create an alternative embodiment of the anti-splatter cover having a translucent window. 
           [0019]      FIG. 7  is a plan view of a blank used to create yet another alternative embodiment of the anti-splatter cover of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention and virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention. 
         [0021]    The terms “a” or “an”, as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term “connected,” as used herein, is an attachment that is not necessarily direct and not necessarily mechanical. 
         [0022]    In  FIG. 1  there is shown a cross-sectional view of an article  10  for preventing food from splattering during microwave cooking. Article  10  can generally be described as a tent or dome defined by a top portion  14  that is surrounded by a side portion  16 . The top portion  14  lies in an intersecting plane with respect to the side portion  16 , to form somewhat of a flat top. Article  10  has an outer surface  18  and an opposite food-facing surface  20 . Desirably, the food-facing surface  20  does not make contact with the food  22  that is being heated. This of course depends on having the user select an appropriately-sized article  10  that will cover the body of food prior to heating. 
         [0023]    In one embodiment of the present invention, water vapor  24  that was generated by heating food  22  may pass through sheet  12 . In another embodiment of the present invention, the food-facing surface  20  may be coated with a material that may affect the transmission of water vapor  24  therethrough. Both embodiments present the advantage that the article  10 , though flexible and foldable, can stand up on its own and are of one-piece construction. 
         [0024]    Article  10  desirably conforms with the shape of a container with which it is to be used. As most dishes have a circular shape, a desired geometrical shape for article  10  is a circular dome. However, various other shapes capable of forming a triangular, rectangular, hexagonal, or other shaped tent may be desired. Regardless of the shape, it is most desirable that the article  10  does not make contact with the food before and after the act of heating occurs. 
         [0025]    Article  10  may be made from a sheet  12  of material, which is capable of being cut into a blank, attached to itself, and folded, and which is stiff enough to hold a preferred shape so that it does not contact the food  22  before or after microwaving. Suitable materials for sheet  12  include paper (e.g. parchment, freezer paper, coffee filter paper) or non-woven materials. One suitable material for the sheet  12  is a spunbond made from rayon, polypropylene, and/or polyester (including the most common polyester for fibers—poly ethylene terephthalate or PET). As used herein, the term “spunbond” web or facing generally refers to a web containing small diameter substantially continuous fibers. The fibers are formed by extruding a molten thermoplastic material from a plurality of fine, usually circular, capillaries of a spinnerette with the diameter of the extruded fibers then being rapidly reduced as by, for example, eductive drawing and/or other well-known spunbonding mechanisms. The production of spunbond webs is described and illustrated, for example, in U.S. Pat. No. 4,340,563 to Appel, et al., U.S. Pat. No. 3,692,618 to Dorschner, et al., U.S. Pat. No. 3,802,817 to Matsuki, et al., U.S. Pat. No. 3,338,992 to Kinney, U.S. Pat. No. 3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman, U.S. Pat. No. 3,502,538 to Levy, U.S. Pat. No. 3,542,615 to Dobo, et al., and U.S. Pat. No. 5,382,400 to Pike, et al., which are incorporated herein in their entirety by reference thereto for all purposes. Spunbond fibers often have a diameter of from about 10 to about 20 micrometers. 
         [0026]    In another embodiment of the present invention, sheet  12  is a tea-bag paper made with a blend of wood and vegetable fibers. The vegetable fiber may be bleached or unbleached cellulosic pulp from wood (e.g. abaca hemp, a small plantation tree grown for the fiber). Desirably, the tea-bag paper has a heat-sealable thermoplastic such as PVC or polypropylene, as a component fiber, at least on the food-facing surface  20 . 
         [0027]    In yet another embodiment of the present invention, sheet  12  is a 1-1.2 ounce nonwoven material that does not contain cellulosic fibers. Like the tea-bag paper, this material is desirable because it may be permanently attached to itself with methods such as ultrasonic, pressure, or thermal bonding methods without the use of additional adhesives. 
         [0028]    The food-facing surface  20  of article  10  may be coated with a material that allows the food-facing surface  20  to be cleanable by wiping so that the article  10  may be used for two or three uses instead of a single use. For example, it is contemplated that sheet  12  may be a laminate of paper/nonwoven materials, and a plastic material. In one embodiment, a paper or nonwoven material is laminated to a thin sheet of polyester, polyethylene, or similar material. In a desired embodiment, a paper or nonwoven material is coated at the food-facing surface  20  with a polytetrafluoroethene or polytetrafluoroethylene coating. 
         [0029]    With respect to the embodiment of the present invention having a laminated sheet  12 , after the article  10  is used, the food-facing surface  20  may be wiped so that the article  10  may be used to cover another type of food for heating. It is not intended that the article  10  will be fully cleaned after wiping; the act of wiping merely extends the use of article  10  through the preparation of a single meal. For example, a user may wish to reheat a plate of meat, a dish of vegetables, and a cup of sauce, separately in that order. After the meat has been heated underneath the article  10 , the user may wipe the food facing surface  20  with a paper towel or cloth. Article  10  is then used to cover the dish of vegetables for heating. Article  10  is again removed and may be wiped so that it can be used to cover the cup of sauce for heating. The article  10  is disposed in the trash after the three uses. 
         [0030]    Sheet  12  is formed into a blank  30  shown in  FIG. 2 . In this particular embodiment, the blank  30  is cut into a cross-shape that fits within a circular area. Generally, blank  30  can be described as a circular sheet having a plurality of notched areas  40  therein. The blank  30  is defined by a top portion  14  surrounded by a number of panels  32 - 38  that together form the side portion  16  after the blank is fully assembled. A major radius  42  of blank  30  is measured from center point  44  to the mid-point of an outer edge  46  of a panel  16 . A minor radius  48  of the top portion  14  is measured from center point  44  to the apex  50  of the notched area  40 . The notched areas  40  are defined by inner edges  52  that converge at apex  50  at an angle  54 . 
         [0031]    In the embodiment shown in  FIG. 2 , the major radii  42  of each panel  16  are substantially equivalent. However, it is contemplated opposing panels may have different major radius  42  values. For example, panels  34  and  38  may have major radii  42  that are substantially equivalent; and panels,  32  and  36  may have major radii  42  that are substantially equivalent. However, the major radii  42  of panels  34  and  38  may be different from the major radii  42  of panels  36  and  32 . This would be the case if blank  30  had an overall oval shape. 
         [0032]    In the embodiment shown in  FIG. 2 , the minor radius  48  between each panel is substantially equivalent. However, it is contemplated that one or more of the minor radii  48  may be different. For example, suppose the minor radius  48  located between panels  34  and  36  was longer than the other major radii  48 , which are equal. This example results in a shape that is symmetrical about an access that is parallel to the major radius  48  located between panels  34  and  36 . 
         [0033]    A blank  30 , such as that shown in  FIG. 2 , may be assembled by bringing each inner edge  52  together and forming a permanent attachment. For example, each corner  60  may be brought together and a seam  62  formed from corners  60  to apex  50 . Seam  62  may be a fin-seam as shown in  FIG. 2A . Desirably, the fin-seem is created by binding the food-facing surface  20  together. As mentioned previously, the permanent attachment may be made by ultrasonic bonding, thermal bonding, pressure bonding methods, or by other methods such as sewing, gluing, or crimping (as is known in the coffee filter art). Suitable adhesives include a polyamide or polypropylene based with very little ethylene content. For example, two possible adhesives are Huntsman RT2115 or Huntsman RT2215, available from Huntsman International LLC. However, it is contemplated that various other adhesives may be used provided that they are food safe and can withstand microwave heating. 
         [0034]    The article  10  is sufficiently light to allow it to be draped over food  20  for heating, but it is also sufficiently heavy to prevent the microwave sheet  12  from being blown off by steam during the microwave heating of food. The stiffness of sheet  12  is such that when the seams  62  are formed, they act as structural members. (Stiffness may be determined by the following: “Standard Test Method for Stiffness of Nonwoven Fabrics Using the Cantilever Test,” Standard Test: IST 90.1 (95), pp. 77-78; or ASTM D5732-95(2001) “Standard Test Method for Stiffness of Nonwoven Fabrics Using the Cantilever Test”.) When more seams are used to create article  10 , such as when there are more than four panels, it may be possible to use a sheet  12  with reduced stiffness as compared to an article  10  with fewer seams. 
         [0035]    Article  10  may be sized to completely cover a dish  64  so that the outer edge  46  contacts the floor  70  of the microwave cavity  72  (see  FIG. 1 ), or the article  10  may be sized to tent over a dish  64  (see  FIG. 3 ). 
         [0036]    Shown in  FIG. 4  is an article  10  having the same characteristics of the previously described embodiments, with the exception that it includes a translucent window  80 . The translucent window  80  allows a user to observe what is happening with the food  20  as it is being heated. Desirably, the translucent window  80  occupies about 10 to about 40 percent of the overall surface area of the article  10  as calculated from comparing a surface area of blank  30  to a surface area of the translucent window  80 . However, it may be desirable to have the translucent window  80  occupy no more than about 30 percent, or about 25 percent of the overall surface area of blank  30 . 
         [0037]    It is contemplated that the article  10  may include vents (not shown) for letting steam and vapor pass from the food to the microwave cavity. Vents may be desired if the sheet  12  material is air impermeable, or if there is a desire for even greater ventilation than can be offered by sheet material  12 . Vents may be slits or holes that vary in size from about 0.5 mm to about 4 mm in diameter or length. The vents may be placed on the top portion, the side portion, or even the optional translucent window  80 . 
         [0038]    Shown in  FIG. 5  is a blank  30  and window  80  (in an unassembled state) which corresponds to the example of article  10  shown in  FIG. 4 . In this non-limiting example, the inner edges  82  that will be connected to window  80  converge together at the center point  44  at an angle  84  of about 30 to about 48 degrees, or about 32 to about 36 degrees. The window  80  has outer edges  85  converging together at an angle  86  of about 41 to about 54 degrees. Desirably, angle  86  is about 90 degrees. In this particular example, the window  80  replaces the panel  38  of  FIG. 2 . It is contemplated that a second or third window  80  may replace or be incorporated into one of the other panels  32 - 36  ( FIG. 2 ). 
         [0039]    Shown in  FIG. 6  is another non-limiting example of a blank  30  and a window  80 , in an unassembled state. In this embodiment, the panel  38  is truncated leaving a truncated edge  90 . The window  80  is the same area as the removed truncated portion of panel  38  (not shown) with the exception of the addition of margin  92  that is used to connect window  80  to edge  90 . This window  80  is essentially a replacement panel  38 ′. Like the other panels  16 , this panel  16 ′ may have a rounded outer edge  46 . 
         [0040]    Suitable materials for the window  80  include but are not limited to polyethylene and polyester (PET). These films are desirably transparent and food safe. It is contemplated that window  80  may be an air impermeable film, or it may be air impermeable because it contains a plurality of small apertures (about 0.5 mm in diameter) or has a porous structure. 
         [0041]    Regardless of the particular embodiment of the present invention, each apex  50  has notch  94  located therein (see  FIG. 5 ), which is preferably rounded to reduce the stress concentration at the apex  50 . The notch  94  helps to define a margin  98  along each edge  52  for the purpose of connecting the inner edges  52  together as seen in  FIG. 2A . The same principle happens at the inner edges  82 , where there is a notch  94  coinciding with the center point  44 . 
         [0042]    Shown in  FIG. 7  is one example of a blank  30  from which a rectangular version of article  10  is formed. This embodiment of article  10  may be preferred for dishes that are rectangular in shape. Having the same general components and features as the previous embodiments (including a possible window  80 ), this rectangular article  10  will not touch the food that it covers either before or after heating in the microwave. 
         [0043]    Also shown by way of example in  FIG. 7  are various indicia  100  that may be placed at the outer surface  18 . The indicia  100  may be decorative or informational. For example, the indicia  100  may include a pattern, design, picture or the like that is aesthetic in nature. The indicia  100  may also or instead be alphanumeric characters that are informational only, such as a set of instructions or safety warnings, or it may be purely aesthetic. 
         [0044]    Each of the embodiments may be folded flat for storage prior to use. For example, in reference to  FIG. 2 , each of the articles  10  may be flattened by folding the panels  34  and  38  along major radius  42 , so that the food-facing surface  20  is brought into contact with each other. This creates a first fold. The article  10  may be further folded to create a second fold along the major radius  42  coinciding with the panels  32  and  36 . However, it is contemplated that the article  10  may be folded in other flattened configurations, and should not be limited to this single description of folds. 
         [0045]    It is contemplated that the article  10  may be packaged with instructions. Such instructions may include information regarding food safety or the like. For example, the instructions may advise against reusing a wipeable article  10  after a certain period of time. In particular, it may be intended that the wipeable article  10  be disposed of within about 2 hours after its initial use, the rationale being that this is a commonly recommended time for food to sit out before it is considered unadvisable for consumption due to potential bacterial growth. 
         [0046]    In operation, the user unfolds the article  10 , and tents it over the food  22  located on a surface or in a receptacle such as a dish  64 . If the sheet  12  from which the article  10  is constructed is air permeable, steam and water vapor  24  will be primarily emitted into the microwave cavity  72  through the side panels  16  and top portion  14  (see  FIG. 1 ). If the article  10  has a relatively low porosity, or is air impermeable, the steam and water vapor  24  will be released from the interior volume of the article  10  about the outer edge  46  (see  FIG. 4 ). 
         [0047]    If the article  10  does not have a wipeable food-facing surface  20  as described above, desirably, it is disposed of after a single use. If the article  10  has a wipeable food-facing surface  20 , it may be immediately reused about two or more times to complete the preparation of a meal.