Patent Publication Number: US-2009220711-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 bio-degradable cup generally includes a bottom with a peripheral wall extending from the bottom so as to enclose a cup with an open top. A water-proof layer is coated on a top surface of the bottom and the inside of the peripheral wall. A foam layer mounted to the outside of the peripheral wall. The water-proof layer and the foam layer are made by similar material and connected with each other by heat-fusion. The water-proof layer is composed of Polyethylene and Polypropylene, and the foam layer is composed of Polyethylene, Polypropylene and Polylactic Acid. The foam layer includes convex patterns formed on the outside thereof. The foam layer is made by a method which prepares melted plastic material and the melted plastic material is then injected to form the foam layer. 
     One way to connect the foam layer and the peripheral wall is that the foam layer is simply mounted to the peripheral wall, the foam layer is not well secured to the peripheral wall. The other way is that the water-proof layer is used as the adhesive layer for connecting the foam layer to the peripheral wall. However, the water-proof layer might not be spread evenly on the peripheral wall and the foam layer can be separated from the peripheral wall. 
     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 IXPE and the paper cup is securely bounded to inside of the foam 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 an IXPE foam cup in which the paper cup is securely received. 
     The present invention further relates to a method for making a biodegradable cup and the method comprises the following steps: 
     a step of preparing a paperboard with a bio-degradable film coated on at least an inner or outer surface thereof, the paperboard being cut, folded and heat-pressed to be a paper cup; 
     a step of preparing a foam board made by IXPE, the foam board being cut, shaped and folded into pieces and each piece being made to be a foam cup by way of heat pressing; 
     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 bio-degradable 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  FIGS. 1-3 , the method for making the bio-degradable cup of the present invention comprises a step of preparing a paperboard and a biodegradable film  11  being coated on at least inner or outer surface thereof, the paperboard then being cut and folded to be a paper cup  10 . The bio-degradable film  11  is made by Plolylactic Acid (PLA) or any bio-degradable material, or by Polyethylene Terephthalate (PET), Polypropylene (PP), Polyethylene (PE). 
     A step of preparing a foam board  200  made by bio-degradable material or non-bio-degradable material. The bio-degradable material can be Plolylactic Acid (PLA), PHA, Bio-Polymers, bio-degradable plastic, Biomax PET, Fepol, Ecoflex, Mater-be by DuPond Company, or non-bio-degradable material such as Polyethylene Terephthalate (PET), Polypropylene (PP), Polyethylene (PE). The foam board  200  is made by IXPE and applied with a printing process, cutting, folding to be fan-shaped pieces which are then made to be foam cups  20  via necessary steps such as heat pressing or gluing. 
     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 hot-air heating, other known heat pressing, gluing to obtain a sticky or adhesive inner surface. The paper cup  10  is inserted into the foam cup  20  and a proper mold is used to securely connect the paper cup  10  to the foam cup  20 . 
     A step of making a lip  21  around an outer top edge of the foam cup  20 . During the pressing to connect the foam cup  20  and the paper cup  10 , the lip  21  is formed on the outer top edge of 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 foam pad  22  and the foam cup  20  are made by the same material and method. 
     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 . 
     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 heat pressing for making the fan-shaped pieces to be foam cups  20  can be ultra-wave pressing, hot-air heating, ultra-wave pressing or electric heat pressing. A bio-degradable adhesive layer can also be spread on the inner surface of the foam cup  20  so as to connect the paper cup  10 . 
     The foam cup  20  is made form the foam board  200  by way of cutting, folding to be fan-shaped pieces and heat pressing so that no injection molds needed. 
     The connection between the paper cup  10  and the foam cup  20  is by way of heat-fusion to obtain a sticky inner surface of the foam cup  20  so that the paper cup  10  is securely connected thereto. The IXPE foam cup  20  is water proof, oil proof and damp proof so that the bio-degradable cup of the present invention is an ideal cup for most of situations. Besides, the foam cup  20  has good isolation feature to heat and smooth outer surface, easily to be shaped and machined. 
     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.