Patent Publication Number: US-2006005515-A1

Title: Method of wrapping a hot food item

Description:
BACKGROUND OF THE INVENTION  
      This invention relates generally to a method of wrapping a hot food item, and more particularly to a method of wrapping a hot food item in a laminated sheet so that the hot food item does not stick to the laminated sheet.  
      Hot sandwiches, such as burritos, tacos, and the like, are often wrapped in patterned foil wrappers and sold for consumption by customers either at tables in a fast food restaurant or as a take-out item. Some hot sandwiches, such as breakfast burritos, will stick to the inside of the wrapper because the moisture from the hot sandwich cannot escape from the inside of the wrapper. When this happens, the sandwich may fall apart, which makes it messy to eat and generally unappetizing for the customer.  
      Therefore, there is a need for a method of wrapping hot foods so that the foods do not stick to the inside of the wrapping.  
     SUMMARY OF THE INVENTION  
      The present invention meets this need by providing a method of wrapping a hot food item. The method includes providing a laminated sheet including a sheet of machine glazed paper wherein the sheet of machine glazed paper has a slip release coating on a first side, and wherein the sheet of machine glazed paper has a weight of about 13 to about 16 pounds per 3000 ft 2 ; a sheet of foil; and a layer of wax adhering a second side of the sheet of machine glazed paper to the sheet of foil, wherein the layer of wax has a weight of about 4 to about 6 pounds per 3000 ft 2 . The method also includes placing the hot food item on the first side of the sheet of machine glazed paper of the laminated sheet; and wrapping the hot food item in the laminated sheet. The laminated sheet has a water vapor transmission rate sufficient so that the hot food item does not stick to the laminated sheet. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a cross-section of one embodiment of the laminated sheet of the present invention.  
       FIG. 2  is a schematic of one method of making the laminated sheet of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Applicants manufacture a wrapper for chewing gum. Chewing gum wrappers are designed to keep oxygen and water vapor, which are detrimental to the chewing gum, from passing from the outside environment to the inside of wrapper where the chewing gum is located. Chewing gum wrappers are not typically exposed to high temperatures and humidity. However, Applicants unexpectedly found that the chewing gum wrapper has properties which allow it to be used to wrap hot food items without their sticking to the surface of the wrapper and yet retain the food item in appetizing and edible form. Although not wishing to be bound by theory, it is believed that the paper absorbs moisture and the foil and wax retain heat so that the hot foods do not stick to the surface of the wrapper.  
       FIG. 1  shows one embodiment of the laminated sheet  100  of the present invention. The laminated sheet  100  has a sheet of machine glazed paper  105 , having a first side  110  and a second side  115 . The machine glazed paper generally has a weight of about 13 to about 16 pounds per 3000 ft 2 , typically about 15 pounds per 3000 ft 2 . There is a slip release coating  120  on the first side of the sheet of machine glazed paper. The machine glazed paper can be purchased with the slip release coating from Domtar Specialty Paper under the designation bleached slip release machine glazed paper.  
      On the second side  115  of the sheet of machine glazed paper  105  there is a layer of wax  125 . The layer of wax  125  generally has a weight of about 4 to about 6 pounds per 3000 ft 2 , typically about 4.5 pounds per 3000 ft 2 . The layer of wax  125  generally includes a mixture of laminating microcrystalline wax and tackifying resin. The laminating microcrystalline wax is generally present in an amount of about 85 wt % to about 95 wt %, typically about 90 wt %. The laminating microcrystalline wax generally has a melt temperature of about 71° C. to about 82° C., typically about 78° C. The tackifying resin is generally present in an amount of about 5 wt % to about 15 wt %, typically about 10 wt %. The tackifying resin generally has a softening point of about 90° C. to about 98° C., typically about 95° C.  
      There is a sheet of foil  130  above the layer of wax  125 . The sheet of foil  130  is generally about 0.000236 inches to about 0.000275 inches thick. Suitable foils include, but are not limited to, aluminum.  
      When a hot food item is to be wrapped, the laminated sheet is placed foil side down. The slip release coating side of the sheet of machine glazed paper is facing up. The hot food item is placed on the sheet of machine glazed paper and wrapped in the laminated sheet. It is believed that in conjunction with the release coating and the moisture absorption by the machine glazed paper, the water vapor transmission rate is sufficient to allow moisture to escape through the laminated sheet so that the hot food item does not stick to the laminated sheet. It also has dead fold capability which allows the laminated sheet to remain closed once the hot food item is wrapped and to be re-closed if it is opened. The dead fold capability enhances the insulation characteristics of the structure.  
       FIG. 2  shows a schematic of one method of making the laminated sheet of the present invention. The laminator  200  includes a pan  205  which holds the wax laminate to be used in making the laminated sheet. The laminator includes three rolls,  210 ,  215 ,  220 . The first roll can be a gravure cylinder  210 , which has been mechanically etched with cells of sufficient size and shape to apply the desired amount of wax, generally in the range of about 4 to about 6 pounds per 3000 ft 2 , on the sheet of machine glazed paper that will result in a smooth lamination with no voids in the wax film. A doctor blade  230  works in conjunction with the gravure cylinder  210 , wiping the gravure cylinder  210  clean except for the wax left in the cells of the gravure cylinder  210  that is to be applied to the sheet of machine glazed paper.  
      The second roll can be a rubber covered impression roll  215 . It generally has a face length slightly less (about ¼ inch) than the width of the paper web. The rubber covering should be made of a rubber which is resistant to the heat of the wax laminate and the heat of the gravure cylinder  210 . The rubber covering should also have sufficient compression resistance for good wear and resistance to rubber set. Generally, a rubber of about 90 durometer on a Shore A scale will be satisfactory. The covering is ground very smooth. The rubber covered impression roll  215  may have a crown in the middle to compensate for deflection of the roll when down pressure is applied to the stack, if desired.  
      The top roll can be a steel roll  220 . The steel roll  220  can be designed to have sufficient chill water flowing through it so that when the laminated sheet exits the laminator, it has enough strength to maintain its integrity until it can be further chilled.  
      The rolls form one nip point  235  between gravure cylinder  210  and rubber covered impression roll  215  and a second nip point  240  between rubber covered impression roll  215  and steel roll  220 .  
      A roll of machine glazed paper  245  has a slip release coating on one side. The machine glazed paper can be coated with the slip release coating in a previous step, or the machine glazed paper can be purchased with the slip release coating. The roll of machine glazed paper  245  feeds into nip point  235  where the wax laminate is applied to the side of the machine glazed paper without the slip release coating. The wax coated machine glazed paper wraps around the rubber covered impression roll  215 . A roll of foil feeds into the second nip  240  and is laminated to the wax coated machine glazed paper to form a roll of laminated sheet  255 . The roll of laminated sheet  255  is cooled by the chill water in the steel roll  220  so that the laminated sheet maintains its integrity as it exits the laminator. It can be further chilled by additional chill rolls after exiting the laminator (not shown).  
      After exiting the laminator, the roll of laminated sheet  255  can optionally be embossed by embossing rollers (not shown), if desired.  
      The roll of laminated sheet  255  can be slit into smaller rolls, and cut into individual sheets, if desired.  
      While certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the compositions and methods disclosed herein may be made without departing from the scope of the invention, which is defined in the appended claims.