Oriented Film Produced In-Process For Use in the Stretch Film Market

Abstract

Pre-stretched films may be used to increase the rate at which loads can be wrapped and to minimize the exertion required when using conventional stretch films. However, pre-stretched films must generally be stretched in a separate step and stored for several days in order for cling to fully develop. The present disclosure describes compositions, devices, systems, and methods for producing film that eliminate the stretching and storage steps. In particular, the present disclosure relates to the use of selected resins and an angled die to increase the level of orientation in the film as it is formed, thus eliminating the need to stretch the film in a separate step. The present disclosure also relates to the use of a cling agent which eliminates the storage time traditionally required to develop the film's cling properties.

1 . An apparatus for producing oriented film in-process, said apparatus comprising:
 a heated enclosure for heating a resin composition to a predetermined temperature that is equal to or greater than an associated melting temperature for said resin composition;   a die disposed in fluid communication with said heated enclosure for extruding a curtain of melted resin; and   a casting roll for receiving the curtain of melted resin.   
     
     
         2 . The apparatus of  claim 1 , further comprising a secondary chill roll for receiving and quenching said curtain of melted resin. 
     
     
         3 . The apparatus of  claim 1 , wherein said die is disposed at an approximately perpendicular angle measured relative to the plane of the curtain of melted resin as said curtain travels from the die to the casting roll. 
     
     
         4 . The apparatus of  claim 1 , wherein said die is disposed at an approximately horizontal angle measured relative to the plane of the curtain of melted resin as said curtain travels from the die to the casting roll. 
     
     
         5 . The apparatus of  claim 1 , wherein said die is disposed at an angle between approximately perpendicular and approximately horizontal measured relative to the plane of the curtain of melted resin as said curtain travels from the die to the casting roll. 
     
     
         6 . The apparatus according to  claim 5 , wherein said die is disposed at an angle of less than about 90° measured relative to the plane of the curtain of melted resin as said curtain travels from the die to the casting roll. 
     
     
         7 . The apparatus of  claim 1 , wherein said curtain of melted resin is measured with respect to a distance established between the die and a receiving surface of said casting roll. 
     
     
         8 . The apparatus of  claim 7 , wherein said die is disposed at an angle between approximately perpendicular and approximately horizontal measured relative to the plane of the curtain of melted resin as said curtain travels from the die to the casting roll, and a reduced distance between the die and a receiving surface of said casting roll is achieved. 
     
     
         9 . The apparatus of  claim 8 , wherein said die is disposed at an angle between approximately perpendicular and approximately horizontal measured relative to the plane of the curtain of melted resin as said curtain travels from the die to the casting roll, and a plurality of resulting film layers having an increased machine direction orientation is achieved. 
     
     
         10 . The apparatus of  claim 8 , wherein said die is disposed at an angle of less than about 90° measured relative to the plane of the curtain of melted resin as said curtain travels from the die to the casting roll. 
     
     
         11 . A method for producing oriented film in-process, said method comprising:
 heating a resin composition to a predetermined temperature that is greater than an associated melting temperature for said resin composition;   transferring a quantity of melted resin to an associated die; and   extruding a curtain of melted resin from said die onto a casting roll.   
     
     
         12 . The method of  claim 11 , further comprising transferring said curtain of melted resin from said casting roll toward a secondary chill roll for quenching. 
     
     
         13 . The method of  claim 11 , further comprising disposing said die at an approximately perpendicular angle measured relative to the plane of the curtain of melted resin as said curtain travels from the die onto the casting roll. 
     
     
         14 . The method of  claim 11 , further comprising disposing said die at an approximately horizontal angle measured relative to the plane of the curtain of melted resin as said curtain travels from the die onto the casting roll. 
     
     
         15 . The method of  claim 11 , further comprising disposing said die at an angle between approximately perpendicular and approximately horizontal measured relative to the plane of the curtain of melted resin as said curtain travels from the die onto the casting roll. 
     
     
         16 . The method according to  claim 15 , further comprising disposing said die at an angle of less than about 90° measured relative to the plane of the curtain of melted resin as said curtain travels from the die onto the casting roll. 
     
     
         17 . The method of  claim 11 , further comprising measuring said curtain of melted resin with respect to a distance established between a die surface from which the resin composition is extruded and a receiving surface of said casting roll. 
     
     
         18 . The method of  claim 17 , further comprising disposing said die at an angle between approximately perpendicular and approximately horizontal measured relative to the plane of the curtain of melted resin as said curtain travels from the die onto the casting roll, and establishing a reduced distance between the die and a receiving surface of said casting roll. 
     
     
         19 . The method of  claim 18 , further comprising disposing said die at an angle between approximately perpendicular and approximately horizontal measured relative to the plane of the curtain of melted resin as said curtain travels from the die onto the casting roll, and extruding a plurality of resulting film layers having an increased machine direction orientation. 
     
     
         20 . The method of  claim 18 , further comprising disposing said die at an angle of less than about 90° measured relative to the plane of the curtain of melted resin as said curtain travels from the die onto the casting roll.