HEMMING PAPERBOARD METHOD AND APPARATUS TO HEM THE EDGE OF SHEET MATERIAL; A TONGUE, A RECESS INWARDLY OF THE TONGUE, A LAND INWARDLY OF THE RECESS AND A GROOVE BEING MILLED IN THE EDGE

摘要

PCT No. PCT/IB95/00113 Sec. 371 Date May 12, 1997 Sec. 102(e) Date May 12, 1997 PCT Filed Feb. 21, 1995 PCT Pub. No. WO95/23061 PCT Pub. Date Aug. 31, 1995A skiving method comprises forming by milling, along an edge zone of a packaging blank comprised of a liquid-absorbent layer and at least two liquid-barrier layers thereon, a tongue, a recess inwardly of the tongue, a land inwardly of the recess, and a groove inwardly of the land, folding over the edge zone to insert the tongue into the groove, and sealing the edge zone to the remainder of the sheet material, preferably by mechanical pressure alone.!