Patent Publication Number: US-2016236822-A1

Title: Pulp molded container with double-sided coating

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a pulp molded container with double-sided coating, particularly to one that has a perfectly sealed structure formed by binding an inner and an outer pulp molded containers and then coating films on both inside and outside thereof. 
     2. Description of the Related Art 
     Conventional disposable trays are usually made of plastics, polystyrene, or paper pulp, among which the one made of polystyrene would release toxic substances that are harmful to human body when being exposed to heat: plus, it cannot be decomposed by the nature environment. Therefore, it is forbidden to use polystyrene as the materials for disposable trays. 
     On the other hand, most of the disposable trays made of paper pulp contain a mixture with paper pulp and other materials. Such products would have the inner surface softened due to permeating sauces or juices of the food and the outer surface damped for the same reason; in other words, they are not waterproof. To overcome the defect, a waterproof film  102  is molded on the inner surface of a paper pulp container  101  as shown in  FIG. 1 , forming a paper pulp molded container with single side coated  100  that separates the liquids from the contents and solves the problem. However, current process in paper pulp molding is to dry and set the shape of the paper pulp container  101 , then place the film  102  and mold it on the inner surface by vacuuming from the outer surface  103 . The outer surface  103  cannot be vacuum molded since the inner surface is already been through the process. Therefore, the paper pulp molded containers  101  in the market only have single side coated which may get softened due to dampness. Still, they are usually placed in piles for transportation and storage, resulting in the inner surface of one contacting the outer surface of another one and thus having scraps of paper attaching therein; and this may contaminate the contents, especially food. Besides, there are other defects of weak structures for supporting the contents and inability to insulate the heat. In short, there is still room for improvements. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a pulp molded container with double-sided coating that the outside thereof would not be damped and the inside thereof would not have scraps of paper attached. 
     Another object of the present invention is to provide a pulp molded container with double-sided coating that has an enhanced and heat insulating structure. 
     Yet another object of the present invention is to provide a pulp molded container with double-sided coating that can separate the juices from the fresh contents like fishes and poultry to keep the freshness of the contents. 
     In order to achieve the objects mentioned above, the present invention comprises an inner container formed by a pulp molded inner body having a first surface on the inner surface thereof, a second surface on the outer peripheral wall thereof, and a first binding rim extended from the peripheral edge of the opening thereof, having a top surface and a undersurface; an inner film coating and binding with the first surface of the inner body and the upper surface of the first binding rim, so as to form an inner pulp molded container with film coated on the inner surface; an outer container formed by a pulp molded outer body with the opposite shape to the inner container, having a third surface on the inner surface thereof, a fourth surface on the outer peripheral wall thereof, and a second binding rim extended from the peripheral edge of the opening thereof correspondingly to the first binding rim, having a top surface and a undersurface; an outer film coating and binding with the fourth surface of the outer body and the undersurface of the second binding rim, so as to form an outer pulp molded container with film coated on the outer surface that has the opening thereof having the same direction with the one of the inner pulp molded container; and a space left between the second surface of the inner body and the third surface of the outer body when the inner pulp molded container is overlaid on the outer pulp molded container and the undersurface of the first binding rim is bound with the top surface of the second binding rim for binding the inner and outer pulp molded containers to form a pulp molded container with double-sided coating. 
     Moreover, the first and second binding rims thereof further have a piece of film left around the edge to be heat-sealed and form a sealed edge. The second surface of the inner body has a plurality of horizontal protrusions spaced thereon, and the third surface of the outer body has a plurality of vertical protrusions arranged thereon, so as to form an enhancing crisscross structure after binding; or the second surface of the inner body has a plurality of vertical protrusions arranged thereon, and the third surface of the outer body has a plurality of horizontal protrusions spaced thereon, so as to form an enhancing crisscross structure after binding. And the present invention further has a plurality of diversion holes arranged on the bottom surface of the inner pulp molded container to link to the space left between the second and the third surfaces. 
     With structures disclosed above, the present invention overcomes the problem of the conventional pulp molded trays with only single side coated, preventing the liquid from permeating through or softening the inside thereof with dampness. In addition, the perfectly sealed structure prevents from scraps of paper attaching when piling up the present invention, and the double binding structure and the crisscross protrusions in the space in-between further enhances the structure and the heat insulating function. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a pulp molded tray with single side coated structure according to the prior art; 
         FIG. 2  is an exploded view of the present invention in a preferred embodiment; 
         FIG. 2A  is a schematic diagram of the forming of the outer pulp molded container thereof; 
         FIG. 3  is an exploded view of the main structure thereof; 
         FIG. 4A  is a perspective view of the present invention in an applicable embodiment; 
         FIG. 4B  is a perspective of the present invention in another applicable embodiment; 
         FIG. 5  is an exploded view of the structure of the present invention; and 
         FIG. 6  is a partially enlarged view of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 2-6 , in a preferred embodiment, the present invention comprises an inner container  10  and an inner film  20 . The inner container  10  is formed by a pulp inner body  11  molded in an inner mold having a first surface  12  on the inner surface thereof, a second surface  13  on the outer peripheral wall thereof, and a first binding rim  14  extended from the peripheral edge of the opening thereof, having a top surface  141  and a undersurface  142 . The inner film  20  is coating and binding with the first surface  12  of the inner body  11  and the upper surface  141  of the first binding rim  14 , so as to form an inner pulp molded container  30  with film coated on the inner surface. Such structure can be found in the prior art and is illustrated in the upper half of  FIG. 2 . 
     However, the structure disclosed above only has single side coated instead of both sides. The present invention further comprises an outer container  40  and an outer film  50 . The outer container  40  is formed by a pulp outer body  41  molded in an outer mold that has the opposite shape to the inner container  10 . Referring to  FIG. 2 , the outer body  41  has a third surface  42  on the inner surface thereof, a fourth surface  43  on the outer peripheral wall thereof, and a second binding rim  44  extended from the peripheral edge of the opening thereof correspondingly to the first binding rim  14 , having a top surface  441  and a undersurface  442 ; the fourth surface  43  on the outer peripheral wall is on the outer mold and the third surface  42  is facing down in the molding process for the fourth surface  43  to be coated in the next manufacturing process and for fitting the shape of the inner container  10  as well. 
     The outer film  50  is coating and binding with the fourth surface  43  of the outer body  41  and the undersurface  442  of the second binding rim  44 , so as to form an outer pulp molded container  60  with film coated on the outer surface that has the opening thereof having the same direction with the one of the inner pulp molded container  30  as shown in  FIG. 3  for the next binding process. 
     Then, when the inner and outer pulp molded containers  30 ,  60  are individually manufactured, the first and second binding rims  14 ,  44  thereof could have a piece of film—from either the inner film  20  or the outer film  50  or from both—for about 2 mm left around the edge; overlaying the inner pulp molded container  30  onto the outer pulp molded containers  60  and leaving a space  71  left between the second surface  13  of the inner body  11  and the third surface  43  of the outer body  41  as shown in  FIG. 6 , then heat-sealing and binding the undersurface  142  of the first binding rim  14  with the top surface  441  of the second binding rim  44  to form a sealed edge  21 , so as to form a pulp molded container with double-sided coating  70 . The present invention is therefore waterproof. Besides, with the structure of the space  71  between the inner and outer pulp molded containers  30 ,  60 , the present invention is heat insulating as well when being filled with steaming food. 
     In the embodiment, the present invention is designed in a shape of a tray but it is not limited to such application. It can also be a bowl, a packaging box, or a lunch box. On the other hand, the inner film  20  and the outer film  50  can be made of Polyethylene (PE), Polyethylene Terephthalate Glycol (PETG), or Polylactic Acid (PLA), but they still have other applicable materials as well. 
     Furthermore, in this embodiment, the second surface  13  of the inner body  11  has a plurality of horizontal protrusions  131  (as in the direction of the X axis in  FIG. 2 ) spaced thereon, and the third surface  42  of the outer body  41  has a plurality of vertical protrusions  421  in the direction of the Y axis in  FIG. 2 ) arranged thereon, so as to form an enhancing crisscross structure after binding; it is also applicable to have the second surface  13  of the inner body  11  having a plurality of vertical protrusions  421  arranged thereon, and the third surface  42  of the outer body  41  has a plurality of horizontal protrusions  131  spaced thereon. 
       FIG. 4A  is another applicable embodiment of the present invention. In this embodiment, it has the same structures disclosed above but further includes a plurality of diversion holes  31  arranged on the bottom surface of the inner pulp molded container  30  to link to the space  71  left between the second and the third surfaces  13 ,  42  as shown in  FIGS. 4A and 6 . With such structure, the juices or liquids with fresh contents such as fishes, poultry, and steaming food would naturally flow into the diversion holes  31  and further to the space  71  where the uncoated second and third surfaces  13 ,  42  would absorb it directly without having a sponge or other absorbing materials disposed therein, separating the juices and liquids from the fresh contents and further achieving the purpose of keeping the freshness from getting rotten. 
     With the structures disclosed above, the present invention overcomes the problem of the conventional pulp molded trays with only single side coated, preventing the juices and liquids from permeating through, softening the inside thereof with dampness, or causing the contents rotten. In addition, the perfectly sealed structure prevents from scraps of paper attaching when piling up the present invention, and the double binding structure and the crisscross protrusions in the space in-between further enhances the structure and the heat insulating function. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.