Abstract:
A modified atmosphere packaging (MAP) lid ( 100 ) is provided. The lid includes a base ( 102 ); a sachet receiving surface ( 106 ) having a plurality of holes ( 110 ); and a raised perimeter wall (108) enclosing and defining the sachet receiving surface, wherein the sachet receiving surface lies level with or above the base. Also provided is a MAP container ( 150 ) including a MAP lid described herein, a dry chemical sachet ( 170 ) for placement on the sachet receiving surface; an adhesive patch ( 180 ) for sealing onto the raised perimeter wall to retain the dry chemical sachet on the sachet receiving surface; and a MAP carton.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to lids for modified atmosphere packaging (MAP) cartons. 
       BACKGROUND 
       [0002]    The quality attributes of fresh fruits, vegetables, cut flowers, and other perishable agricultural commodities must be maintained as much as possible for as long as possible to ensure consumer acceptability. Quality deterioration of perishable goods comes about through plant tissue enzyme reactions including respiration, ripening and senescence, through microbial growth and through water loss from the tissue. Methods of inhibiting deteriorative enzyme reactions and growth of yeasts, molds and bacteria involve the maintenance of optimal conditions within the packaging of the perishable goods. 
         [0003]    Modified atmosphere packaging (MAP) inhibits deterioration of perishable horticultural and agricultural commodities. MAP technology includes stackable containers that comprising a lid and a carton. US patent publication no. 2014/0116900, incorporated by reference herein in its entirety, discloses a lid with a covered recess for retaining dry chemical sachets that release of beneficial agents into the carton. Further improvements in the design of such lids are desirable. 
       SUMMARY 
       [0004]    The inventions described herein have many aspects, some of which relate to modified atmosphere packaging (MAP) lids and MAP containers comprising such lids. 
         [0005]    In one aspect, a modified atmosphere packaging (MAP) lid is provided. The lid comprises a base; a sachet receiving surface comprising a plurality of holes; and a raised perimeter wall enclosing and defining the sachet receiving surface, wherein the sachet receiving surface lies level with or above the base. 
         [0006]    The plurality of holes may be spaced apart from each other by a distance equal to at least two, three, four, five or ten times a diameter of each of the holes. 
         [0007]    The sachet receiving surface may comprise an outer region defined as an imaginary border region of constant width consisting of half of the surface area of the sachet receiving surface, wherein at least 80%, 85%, 90% or 100% of the plurality of holes are distributed in the outer region. 
         [0008]    The total combined area of the plurality of holes may be less than 2 percent, 1 percent, or 0.5 percent of a total surface area of the sachet receiving surface. 
         [0009]    The MAP lid may comprise more than one sachet receiving surface and more than one raised perimeter wall. 
         [0010]    The sachet receiving surface may be rectangular and may be planar. 
         [0011]    The sachet receiving surface may be concave, wherein a lowermost point of the sachet receiving surface lies level with or above the base. 
         [0012]    The MAP lid may comprise raised corner portions. For example, the MAP lid may be rectangular and comprise four raised corner portions. The raised corner portions may range in height from ¼″ to 5/8″. 
         [0013]    Opposing mid-regions of the MAP lid may comprise raised air flow guides configured to divert at least some incoming air away from a center of the MAP lid. The height of the raised air flow guides may be the same as any raised air corner portions. 
         [0014]    The MAP lid may be made of a polymer material selected from the group consisting of ethylene vinylacetate (EVA), ethylbutyl acetate (EBA), a crosslinked ionomer resin, cast polyester (PET), a polyamide and polycarbonate (PC). The base, the sachet receiving surface, the raised perimeter wall, and any raised corner portions and any raised air flow guides of the MAP lid may be integrally thermoformed from the polymer material. 
         [0015]    In another aspect, a modified atmosphere packaging (MAP) container is provided. The MAP container comprises a MAP lid as described herein, a dry chemical sachet for placement on the sachet receiving surface; an adhesive patch for sealing onto the raised perimeter wall to retain the dry chemical sachet on the sachet receiving surface; and a MAP carton. 
         [0016]    The dry chemical sachet may comprise a releasable agent selected from the group consisting of an insecticide (sulfur dioxide), a preservative (oxygen absorber such as iron carbonate), an anti-microbial (chlorine dioxide), a ripening agent (ethylene), carbon dioxide, and nitrogen. 
         [0017]    The foregoing discussion merely summarizes certain aspects of the inventions and is not intended, nor should it be construed, as limiting the inventions in any way. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0018]    In drawings which show non-limiting embodiments of the invention: 
           [0019]      FIG. 1  is a top view of a MAP lid according to an embodiment of the invention; 
           [0020]      FIG. 2  is a bottom view of the MAP lid of  FIG. 1 ; 
           [0021]      FIG. 3  is a side view of the MAP lid of  FIG. 1 ; 
           [0022]      FIG. 4  is a cross-sectional side view of the MAP lid of  FIG. 1  along section A-A; 
           [0023]      FIG. 5  is a cross-sectional side view of a MAP container comprising the MAP lid according to  FIG. 1 , along a section similar to section A-A of  FIG. 1 ; 
           [0024]      FIG. 6  is a cross-sectional side view of a MAP lid according to another embodiment of the invention, along a section similar to section A-A of  FIG. 1 ; 
           [0025]      FIG. 7  is a cross-sectional side view of a MAP container comprising the MAP lid according to  FIG. 6 , along a section similar to section A-A of  FIG. 1 ; 
           [0026]      FIG. 8  is a partial top view of the MAP lid according to  FIG. 1  showing the sachet-receiving surface; 
           [0027]      FIG. 9  is a top view of a MAP lid according to an embodiment of the invention; 
           [0028]      FIG. 10  is a top view of a MAP lid according to an embodiment of the invention; 
           [0029]      FIG. 11  is a top view of a MAP lid according to an embodiment of the invention; 
           [0030]      FIG. 12  is a top view of a MAP lid according to an embodiment of the invention; 
           [0031]      FIG. 13  is a top view of a MAP lid according to an embodiment of the invention; 
           [0032]      FIG. 14  is a top view of a MAP lid according to an embodiment of the invention; 
           [0033]      FIG. 15  is a cross-sectional side view of the MAP lid of  FIG. 14  along section B-B; 
           [0034]      FIG. 16  is a cross-sectional side view of a MAP container comprising the MAP lid according to  FIG. 14 , along a section similar to section B-B of  FIG. 15 ; 
           [0035]      FIG. 17  is a photograph of avocadoes in a MAP carton after treatment with a chlorine dioxide releasing sachet disposed in a known MAP lid; 
           [0036]      FIG. 18  is a photograph of pomegranates in a MAP carton after treatment with a chlorine dioxide releasing sachet disposed in a known MAP lid; and 
           [0037]      FIG. 19  is a photograph of a recessed sachet receiving surface of a known MAP lid. 
       
    
    
     DESCRIPTION 
       [0038]    Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
         [0039]    Directional conventions are employed in this specification to help clarify their meaning, as follows:
       the term “horizontal” and similar words as used herein are defined as a plane parallel to the base of the MAP lid;   the term “vertical” and similar words as used herein refer to a direction perpendicular to the horizontal, as just defined;   the terms “higher” and similar words as used herein refer to a position or orientation relatively closer to a point above the MAP lid;   the term “lower” and similar words as used herein refer to a position or orientation relatively closer to a point below the MAP lid;   the term “inner” and similar words as used herein refer to a position or orientation relatively closer to the middle of the MAP lid;   the term “outer” and similar words used herein refer to a position or orientation relatively further away from the middle of the MAP lid;       
 
         [0046]      FIGS. 1 to 5 and 8  show a MAP lid  100  according to an embodiment. MAP lid  100  is rectangular. In other embodiments, MAP lid  100  may be square, oval, triangular, or any other shape that matches the shape of its corresponding carton. MAP lid  100  may for example be thermoformed from a polymer material. Exemplary polymer materials include ethylene vinylacetate (EVA), ethylbutyl acetate (EBA), a crosslinked ionomer resin, cast polyester (PET), polyamide or polycarbonate (PC). 
         [0047]    MAP lid  100  includes a base  102  and raised corner portions  104  at each corner. Base  102  is generally planar. Raised corner portions  104  each extend vertically from base  102  by a height H. In some embodiments, height H may be ¼″ to 5/8″, which is shorter than the ¾″ height of raise corner portions of MAP lids of conventional MAP containers. Because the height of the raised corner relates directly to the overall height of vertically stacked MAP containers, the shorter raised corner portions  104  of the invention permit a greater number of MAP containers to be vertically stacked on a pallet. The present inventors have also determined that resulting narrower open space between stacked MAP containers results in greater air velocity between the MAP containers compared to that achieved with conventional MAP containers with lids having conventionally-sized raised corner portions. The present inventors have determined that this greater air velocity compensates for the narrower open space, resulting in a similar volume of air to pass between the MAP containers as compared to conventional MAP containers. 
         [0048]    MAP lid  100  includes a sachet receiving surface  106  surrounded by a raised perimeter wall  108 . As shown in  FIG. 4 , sachet receiving surface  106  lies level with the plane of base  102 . In other embodiments, sachet receiving surface  106  may lie above the plane of base  102 , as shown for example in  FIG. 6  showing MAP lid  200 . Features of MAP lid  200  are otherwise similar to correspondingly numbered features of MAP lid  100 . 
         [0049]    Sachet receiving surfaces of known MAP lids such as those disclosed in US patent publication no. 2014/0116900 are recessed within the base. In contrast, the present invention advantageously provides the sachet receiving surface at or above the level of the base so that (i) the volume of the container available to hold produce is maximized and (ii) the distance between the sachet and the produce is maximized to facilitate greater dispersion of releasable agents from the sachet prior to their contact with the produce. 
         [0050]      FIG. 5  shows a MAP container  150  including MAP lid  100 , a MAP container  160 , sachet  170 , and an adhesive patch  180 . MAP lid  100  is fitted onto MAP container  160 . Sachet  170  is placed on sachet receiving surface  106  of MAP lid  100 . Adhesive patch  180  is sealed onto raised perimeter wall  108  to retain sachet on sachet receiving surface  106 . Sachet  170  may be a dry chemical sachet as described for example in US patent publication no. 2014/0116900. For example, sachet  170  may comprise a beneficial releasable agent such as an insecticide (sulfur dioxide), a preservative (oxygen absorber such as iron carbonate), an antimicrobial (chlorine dioxide), a ripening agent (ethylene), carbon dioxide, or nitrogen. 
         [0051]    Sachet receiving surface  106  includes a plurality of holes  110  for allowing beneficial releasable agents from sachet  170  to pass into the MAP container. The present inventors have determined, however, that in conventional MAP lids as described for example in US patent publication no. 2014/0116900, produce can be damaged from overexposure to, and/or high concentrations of, releasable agents from the sachet. Certain embodiments of the invention therefore relate to MAP lids with a controlled location, spacing and/or size of holes  110  to control exposure of the produce to the sachet releasable agents. 
         [0052]    In MAP lid  100 , holes  110  are distributed along an outer region  112  of sachet receiving surface  106 . Outer region  112  may be defined as an imaginary border region of constant width consisting of half of the surface area of sachet receiving surface  106 . In MAP lid  100 , 100% of holes  110  are disposed along outer region  112 . In some embodiments, at least 95%, 90%, 85%, or 80% of the holes are disposed in the outer region. In other embodiments, holes  110  may be distributed evenly or randomly throughout sachet receiving surface  106 . 
         [0053]    As shown best in  FIG. 8 , holes  110  of MAP lid  100  are spaced apart such that the distance D 2  between adjacent holes  110  is at least four times greater than the diameter D 1  of each hole. In some embodiments, the distance D 2  between adjacent holes may be at least two times, three times, five times, or ten times greater than the diameter D 1  of each hole. 
         [0054]    In MAP lid  100 , the combined total area of holes  110  is less than 5 percent of the total surface area of sachet receiving surface  106 . In some embodiments the holes may be less than 2 percent, 1 percent, or 0.5 percent of the total surface area of sachet receiving surface. 
         [0055]      FIG. 9  shows a MAP lid  300  according to another embodiment of the invention. Features of MAP lid  300  are similar to correspondingly numbered features of MAP lid  100 . MAP lid  300  differs from MAP lid  100  in that sachet receiving surface  306 , and therefore raised perimeter wall  308 , are oval instead of rectangular. 
         [0056]      FIG. 10  shows a MAP lid  400  according to another embodiment of the invention. Features of MAP lid  400  are similar to correspondingly numbered features of MAP lid  100 . MAP lid  400  differs from MAP lid  100  in that MAP lid  400  has two sachet receiving surfaces  406 ,  406 ′, and two corresponding raised perimeter walls  408 ,  408 ′. In still other embodiments, more than two sachet receiving surfaces and corresponding raised perimeter walls may be provided. 
         [0057]      FIG. 11  shows a MAP lid  500  according to another embodiment of the invention. Features of MAP lid  500  are similar to correspondingly numbered features of MAP lid  100 . MAP lid  500  differs from MAP lid  100  in that MAP lid  500  has two adjacent sachet receiving surfaces  506 ,  506 ′, separated and enclosed by two corresponding raised perimeter walls  508 ,  508 ′ that share a common wall  514 . 
         [0058]      FIG. 12  shows a MAP lid  600  according to another embodiment of the invention. MAP lid  600  is similar to MAP lid  100  but includes two pairs of air flow guides  620 ,  620 ′ along mid portions of lid  600  between corner posts  604 . In other embodiments, one pair or more than two pairs of air flow guides  620 ,  620 ′ may be provided. For example, in some other embodiments four pairs of air flow guides  620 ,  620 ′ may be provided, with a pair disposed along each mid portion of lid  600  between each corner posts  604 . 
         [0059]    Air flow guides  620 ,  620 ′ divert at least some of the incoming air flowing across the top of MAP lid  600  away from the middle of MAP lid  600 , as shown by the arrows in  FIG. 12 . Partial diversion of the incoming air flow provides for more even distribution of air flow between stacked MAP containers utilizing MAP lid  600 . In some embodiments, air flow guides  620 ,  620 ′ extend vertically to the same height as corner posts  604 , thereby contacting and bearing some of the weight of the bottom of the MAP carton stacked above it, providing the additional stacking support to MAP containers utilizing MAP lid  600 . 
         [0060]      FIG. 13  shows a MAP lid  700  according to another embodiment of the invention. MAP lid  700  is similar to MAP lid  600  but instead of two paired air flow guides provides four single air flow guides  720  along mid portions of lid  700  between corner posts  704 . 
         [0061]    In the embodiments shown, air flow guides  620 ,  620 ′ and  720  are shown as curved elements. In other embodiments, the air flow guides may be linear, or any other shape suitable for facilitating at least partial diversion of air flow from the middle of the MAP lid. In some embodiments the air flow guides may be located along outer regions of the MAP lid, adjacent or abutting the side edges of the MAP lid. In other embodiments, the air flow guides may be located in a more inner region of the MAP lid. 
         [0062]      FIGS. 14 to 16  show a MAP lid  800  and MAP container  850  according to another embodiment of the invention. Features of MAP lid  800  and MAP container  850  are similar to correspondingly numbered features of MAP lid  100  and MAP container  150 . MAP lid  800  differs from MAP lid  100  in that instead of a sachet receiving surface, MAP lid  800  has a hole  814  for receiving a sachet-containing insert  890 . Sachet-containing insert  890  contains sachet  870 . The depth D to which sachet-containing insert  890  suspends into hole  814  of MAP lid  800  is controlled such that the bottom  806  of sachet-containing insert  890  lies level with or above lid base  802 . The depth may be controlled by predetermining the height of raised perimeter wall  808  and/or predetermining the thickness of sachet-containing insert  890 . Bottom  806  of sachet-containing insert  890  includes holes  810  in a similar manner to holes  110  along sachet receiving surface  106  of MAP lid  100 . 
       EXAMPLES 
       [0063]    In Experiment 1, avocadoes were placed in two MAP cartons. The first MAP carton was covered with a known MAP lid having a recessed sachet receiving surface with a plurality of holes distributed throughout the sachet receiving surface similar to the lids illustrated in US patent publication no. 2014/0116900.  FIG. 19  shows the recessed sachet receiving surface of the known MAP lid. The second MAP carton was covered with a MAP lid according to an embodiment of the present invention, in particular a MAP lid having a sachet receiving surface level with the base of the MAP lid, and a hole located in the outer region adjacent each corner of the sachet receiving surface, the combined total area of the four holes not exceeding 2 percent of the total surface area of the sachet receiving surface. Dry chemical sachets containing 1 gram of chlorine dioxide were placed on the sachet receiving surfaces and sealed.  FIG. 17  shows the condition of the avocadoes in the first MAP carton after 21 days. As evident from  FIG. 17 , the avocadoes located in the area corresponding to the area below and adjacent the sachet receiving surface of the known MAP lid suffered damage. None of the avocadoes in the second MAP carton after 21 days did not showed any damage. 
         [0064]    In Experiment 2, the protocol of Experiment 1 was followed except pomegranates were used in place of avocadoes.  FIG. 18  shows the condition of the pomegranates in the first MAP carton after 21 days. As evident from  FIG. 18 , the pomegranates located in the area corresponding to the area below and adjacent the sachet receiving surface of the known MAP lid suffered damage. None of the pomegranates in the second MAP carton after 21 days did not showed any damage. 
         [0065]    This application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. Accordingly, the scope of the claims should not be limited by the preferred embodiments set forth in the description, but should be given the broadest interpretation consistent with the description as a whole.