Patent Publication Number: US-2009218390-A1

Title: Bio-degradable cup and method for making the same

Description:
FIELD OF THE INVENTION 
     The present invention relates to a bio-degradable cup and a method for making the same. 
     BACKGROUND OF THE INVENTION 
     A conventional biodegradable cup generally includes an inner cup which is used to receive food and does not deform, and a paper outer paper cup in which the inner cup is received. The inner cup is made by bio-degradable material and is made by way of super-critical carbon dioxide extrusion. The paper outer cup includes printed material on outside thereof. 
     However, the inner cup and the paper outer cup are simply engaged with each other so that the inner cup may shift relative to the paper outer cup. The inner cup may also become soft when hot food is received in the inner cup and this results health concerns. 
     The present invention intends to provide a bio-degradable cup which includes a paper cup connected to inside of a foam cup which is made by bio-degradable material and the paper cup is securely bounded to inside of the foam cup. A bio-degradable film is coated to the inside of the paper cup. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a bio-degradable cup which comprises a paper cup with a bio-degradable film coated to an inside thereof and a foam cup in which the paper cup is received. The foam cup is made by microfoam which is made by way of super-critical carbon dioxide extrusion. A lip is connected to a top edge of the foam cup and a foam pad is connected to an underside of the foam cup. 
     The present invention further relates to a method for making a bio-degradable cup, and the method comprises the following steps: 
     a step of preparing a paperboard with bio-degradable film coated on at least inner or outer surface thereof, the paperboard then being cut and folded to be a paper cup; 
     a step of preparing a foam board made by biodegradable plastic which is treated by way of super-critical carbon dioxide extrusion, the foam board being cut into pieces and each piece being made to be a foam cup; 
     a step of applying a heat treatment to an inside of the foam cup to obtain a sticky inner surface of the foam cup and the paper cup being securely connected to the sticky inner surface of the foam cup, and 
     a step of making a lip around an outer top edge of the foam cup. 
     The primary object of the present invention is to provide a cup suitable for receiving food and can be bio-degradable. 
     Another object of the present invention is to provide a method for making the bio-degradable cup. 
     The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows steps of the method for making the bio-degradable cup of the present invention; 
         FIG. 2  shows a foam pad is to be connected to an underside of the foam cup; 
         FIG. 3  is a cross sectional view to show the biodegradable cup of the present invention; 
         FIG. 4  shows that the foam cup is made by the foam piece; 
         FIG. 5  shows another embodiment of the bio-degradable cup of the present invention, wherein the lip is separately made and then connected to the foam cup, and 
         FIG. 6  shows a further embodiment of the bio-degradable cup of the present invention, wherein the top edge of the foam cup is located at ⅓ height from the bottom of the paper cup. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , the method for making the bio-degradable cup of the present invention comprises a step of preparing a paperboard with bio-degradable film  11  coated on at least inner or outer surface thereof, the paperboard then being cut, folded and heat-pressed to be a paper cup  10 . The bio-degradable film  11  is made by Plolylactic Acid (PLA), Bio-Polymers, bio-degradable plastic or any plastic material meets requirements ISO14855 and suitable to be composted. 
     A step of preparing a foam board  200  made by bio-degradable plastic or non-bio-degradable plastic which is treated by way of super-critical carbon dioxide extrusion. The foam board  200  is a microfoam and is applied with a printing process which can be water relief printing, intaglio printing, lithography, screen printing or rotary screen. Desired patterns or characters can be printed to the outside of the foam board  200  and the foam board  200  is cut into pieces and each piece is made to be a foam cup  20  via necessary steps such as folding, ultra-sonic heat pressing, ultra-wave pressing, hot-air heating, or electric heat pressing. The bio-degradable plastic is one of Plolylactic Acid (PLA), Bio-Polymers, or bio-degradable plastic. The non-bio-degradable plastic is one of Polyethylene (PE), Polypropylene, or Polyethylene Terephthalate (PET). 
     A step of applying a heat treatment to an inside of the foam cup  20  to obtain a sticky inner surface of the foam cup  20  and the paper cup  10  securely connected to the sticky inner surface of the foam cup  20 . The heat treatment can be any known ways such as ultra-sonic heating, electric heating, ultra-wave heating or hot-air heating. The temperature of the heat treatment to the inside of the foam cup  20  is about 60° C. or higher than 60° C. to make the inside of the foam cup  20  to be sticky and the paper cup  10  is inserted into the foam cup  20 . A proper mold is used to securely connect the paper cup  10  to the foam cup  20 . The inside of the foam cup  20  can also be applied a layer of bio-degradable Bio-polymer which is adhesive so as to securely connect the paper cup  10 . 
     A step of making a lip  21  around an outer top edge of the foam cup  20 . The lips  21  of adjacent bio-degradable cups are in contact with each other when the bio-degradable cups are piled up. As shown in  FIG. 4 , the lip  21  can be formed by pressing an outward portion along the top edge of each fan-shaped piece so that the outward portion  201  forms the lip  21  when the foam cup  20  is formed. 
     As shown in  FIG. 5 , the lip  21  can be made by another foam board which has different thickness from the foam board  200  to be made the foam cup  20 , the lip  21  is securely connected to top edge of the foam cup  20 . The paper cup  10  can be connected with the foam board  200  after or before the connection of the lip  21  and the foam cup  20 . 
     A step of connecting a foam pad  22  to an underside of the foam cup  20  and a diameter of the foam pad  22  being the same as an outer diameter of the foam cup  20 . 
     The bio-degradable cup of the present invention made by the method described above comprises a paper cup  10  with a biodegradable film  11  coated to an inside thereof and a foam cup  20  in which the paper cup  10  is securely received. As shown in  FIG. 3 , the paper cup  10  includes another lip which protrudes outward from a top edge of the paper cup  10  and then is curved inward. The another lip on the paper cup  10  is rested on the lip  21  of the foam cup  20 . 
     As shown in  FIGS. 1-5 , the outward and curved lip on the paper cup  10  is rested on the lip  21  on the foam cup  20  when the bio-degradable cups are piles up. As shown in  FIG. 6 , the top edge of the foam cup  20  is located at about ½ to ⅓ height from the bottom of the paper cup  10 . A lower edge of the foam cup  20  is in flush with a bottom of the paper cup. 
     The biodegradable film  11  is made by Plolylactic Acid (PLA), PHA, Bio-Polymers, bio-degradable plastic, Biomax PET, Fepol, Ecoflex, Mater-be by DuPond Company, or any plastic material suitable to be composted and meets requirements of International Standard Organization. The bio-degradable plastic is one of Plolylactic Acid (PLA), Bio-Polymers, bio-degradable plastic or Thermoplastic that is suitable to be composted. The foam material for the foam cup  20  can be Polyethylene (PE), Polypropylene (PP), or Polyethylene Terephthalate (PET). 
     While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.