| 摘要 |
PCT No. PCT/FI97/00155 Sec. 371 Date Sep. 10, 1998 Sec. 102(e) Date Sep. 10, 1998 PCT Filed Mar. 10, 1997 PCT Pub. No. WO97/33745 PCT Pub. Date Sep. 18, 1997A method of manufacturing a core, especially a spiral core, from superimposed plies of board produced by winding, gluing, and drying them, is provided. The method is practiced so that the moisture content of at least some of the board plies entering the winding stage differ from each other in order to provide a stepwise moisture structure within the core wall. This decreases unfavorable stresses which are produced in the drying stage if a core is manufactured from plies having equal moisture content. |
