LOW STRESS FLAT END COVER ARRAY CONSTITUTION FOR BOXBOARD VESSEL COATED WITH THERMOPLASTIC PLASTIC

摘要

PURPOSE: To prevent impairment of the quality of a product caused by the fracture of each layer by forming an edge portion of a free edge of an oblique score line separately from a corner portion of the free edge by the distance substantially equal to the predetermined distance of the converging score line. CONSTITUTION: An oblique scope line 46 is formed from an intersection of the score lines 36, 38 to a free edge 48 of an underlying closure panel 12 across the underlying closure panel 12, and the oblique score line forms an inward fold panel segment 12a and a triangular fold-back panel segment 12b. An obliquid score line 50 is formed from an intersection of a horizontal score line 36 and a vertical score line 44 to a free edge 52 of an underlying closure panel 20 across the underlying closure panel 20. The converging score lines 54, 56 are formed from the intersections of the score lines 36/40 and the score lines 36/42 of an underlying closure panel 16 to a free edge portion 58 of the underlying closure panel 16. The edge portions of the score lines 54, 56 at the free edge portion 58 are separated from each other by the predetermined distance (d) from the edge portions 32 and 34 to the score lines 46 and 50 respectively along the free edges 48 and 52.