초록 ▼

A method for forming a deep drawn paperboard container coated with a layer of grease and water impermeable polymeric material. A paperboard blank is disposed between and acted upon by a heated mandrel and a heated mold to form a container. The surface of the blank engageable by the mandrel bears the

A method for forming a deep drawn paperboard container coated with a layer of grease and water impermeable polymeric material. A paperboard blank is disposed between and acted upon by a heated mandrel and a heated mold to form a container. The surface of the blank engageable by the mandrel bears the polymeric coating, and means are operative relatively to move the mandrel and mold toward one another, to engage, the blank, and, just prior to fully engaging the blank to set the same, to introduce a film of air between the heated mandrel and the polymer coated surface to ensure against sticking of the coating to the mandrel.

대표청구항 ▼

1. A method of deep drawing a container from a paperboard blank having a layer of polymeric material on at least one side thereof, comprising the steps of: providing a female mold and a mandrel having the shape of the outside and inside, respectively, of said container, and movable between an open p

1. A method of deep drawing a container from a paperboard blank having a layer of polymeric material on at least one side thereof, comprising the steps of: providing a female mold and a mandrel having the shape of the outside and inside, respectively, of said container, and movable between an open position and a blank forming closed position; disposing said blank between said female mold and said mandrel in said open position thereof, so that said side having said layer is presented toward said mandrel; heating said female mold and said mandrel to temperatures in a range of from about 200° F. to about 350° F., said temperatures being sufficient to set the paperboard blank and capable of damaging said layer; relatively moving said heated female mold and said heated mandrel toward one another into the recited closed position thereof to engage said blank and urge the latter into conformity with said female mold and said mandrel; and, just prior to movement to the recited closed position of said female mold and said mandrel, introducing and confining a film of compressible fluid between said mandrel and said side of said blank and said layer to ensure against damage to the latter by said heated mandrel. 2. The method of claim 1, wherein said layer of polymeric material is from about 1 mil to about 1.5 mils thick, and said paperboard is from about 18 point caliper to about 24 point caliper. 3. The method of claim 1 or 2, wherein said polymeric material is selected from the group consisting of polyester, polyamide, polypropylene, polyethylene, and polysulfone. 4. The method of claim 3, wherein said compressible fluid is introduced as recited upon relative movement of said female mold and said mandrel to within about 1/16 inch of said closed position. 5. The method of claim 3, wherein said compressible fluid is air. 6. The method of claim 5, wherein said compressible fluid is introduced as recited upon relative movement of said female mold and said mandrel to within about 1/16 inch of said closed position. 7. A method of deep drawing a container from a paperboard blank having a layer of polymeric material on at least one side thereof, comprising the steps of: providing a female mold and a mandrel having the shape of the outside and inside, respectively, of said container, and movable between an open position and a blank forming closed position; disposing said blank between said female mold and said mandrel in said open position thereof, so that said side having said layer is presented toward said mandrel; heating said female mold and said mandrel to substantially the same temperature in a range of from about 200° F. to about 350° F., said temperature being sufficient to set the paperboard blank and capable of damaging said layer; relatively moving said heated female mold and said heated mandrel toward one another into the recited closed position thereof to engage said blank and urge the latter into conformity with said female mold and said mandrel; and, just prior to movement to the recited closed position of said female mold and said mandrel, introducing and confining a film of compressible fluid between said mandrel and said side of said blank and said layer to ensure against damage to the latter by said heated mandrel. 8. The method of claim 7, wherein said layer of polymeric material is from about 1 mil to about 1.5 mils thick, and said paperboard is from about 18 point caliper to about 24 point caliper. 9. The method of claim 7 or 8, wherein said polymeric material is selected from the group consisting of polyester, polyamide, polypropylene, polyethylene, and polysulfone. 10. The method of claim 9, wherein said compressible fluid is introduced as recited upon relative movement of said female mold and said mandrel to within about 1/16 inch of said closed position. 11. The method of claim 9, wherein said compressible fluid is air. 12. The method of claim 11, wherein said compressible fluid is introduced as recited upon relative movement of said female mold and said mandrel to within about 1/16 inch of said closed position. 13. A method of deep drawing a paperboard container, comprising: providing a female mold and a mandrel operative for engagement with one another in a closed disposition thereof; providing a paperboard container blank having a layer of liquid impermeable material on at least one side thereof, said material comprising a polymer coating selected from the group consisting of polyester, polyamide, polypropylene, polyethylene, and polysulfone; disposing said blank between said female mold and said mandrel so that said side having said layer is presented toward said mandrel; heating said female mold and said mandrel to substantially the same temperature in a range from about 200° F. to about 350° F., said temperature being sufficient to set the paperboard blank; relatively moving said female mold and said mandrel toward one another into the recited closed disposition thereof to engage said blank and urge the latter into conformity with said female mold and said mandrel; and, just prior to movement to the recited closed disposition of said female mold and said mandrel, introducing and confining a film of compressible fluid between said mandrel and said side of said blank having said layer. 14. The method of claim 13, wherein said polymer coating is from about 1 mil to about 1.5 mils thick, and said paperboard is from about 18 point caliper to about 24 point caliper. 15. The method of claim 13 or 14, wherein said compressible fluid is introduced as recited upon relative movement of said female mold and said mandrel to within 1/16 inch of said closed disposition thereof. 16. The method of claim 13 or 14, wherein said compressible fluid is air. 17. The method of claim 16, wherein said compressible fluid is introduced as recited upon relative movement of said female mold and said mandrel to within 1/16 inch of said closed disposition thereof. 18. The method of claim 1, 7 or 13, wherein said blank is placed over said female mold, and said mandrel alone is moved from the recited open position toward said female mold into the recited blank forming closed position of said female mold and said mandrel. 19. The method of claim 18, wherein said compressible fluid is introduced as recited upon movement of said mandrel to within about 1/16 inch of closed position with said female mold.