초록 ▼

A method for making an article, such as a plastic food container lid having frangible score lines. The article is formed of a sheet of plastic material having substantially constant thickness with score lines defining an offset portion thereof which is connected to the remaining sheet material by a

A method for making an article, such as a plastic food container lid having frangible score lines. The article is formed of a sheet of plastic material having substantially constant thickness with score lines defining an offset portion thereof which is connected to the remaining sheet material by a segment that is thinner than the sheet material and being rupturable for the removal of the offset portion. The periphery of the inwardly directed portion of the offset portion overlaps the periphery of the outwardly directed portion of the offset portion on the opposite side of the sheet material. The fracturable score lines are corrugated along their length by a plurality of successive grooves and ridges with the grooves extending deeper into the material than the ridges.

대표청구항 ▼

A method for forming finger rupturable frangible score lines in a plastic container lid of rigid plastic sheet material to provide a finger removable portion in said plastic container lid comprising: (a) selecting said lid of rigid plastic sheet material adapted for use in food and beverage containe

A method for forming finger rupturable frangible score lines in a plastic container lid of rigid plastic sheet material to provide a finger removable portion in said plastic container lid comprising: (a) selecting said lid of rigid plastic sheet material adapted for use in food and beverage containers; (b) placing said lid of sheet material over a female die member having a serrated edge associated therewith, said sheet material of said lid overlapping the edges of said female die member; and, (c) applying force to said lid of sheet material on the opposite side of said material from said female die by means of a punch member which slightly overlaps the edges of said female die whereby said fracturable score line is formed having corrugations corresponding to the points and notches of said serrated edge of said female die to form said finger rupturable frangible score line in said rigid plastic sheet material of said plastic container lid.