PURPOSE: To provide a process for continuous preparation of a sealing sheet impervious to water and/or oil, having a good sealing effect, etc.
CONSTITUTION: A four-layered structure, which has a substrate layer, a swellable clay layer and a covering layer comprising a non-woven material, and is additionally strewn with a swellable clay on the top side of the covering layer, is needle punched to allow the swellable clay on the top layer to be incorporated in the non-woven material covering layer, and then the swellable clay in the covering layer is moistened and dried again. In a modified example, a laminate wherein a non-woven material or a random fiber non-woven material wherein a large-pored non-woven material or a non-consolidated intersecting fiber is crimped is laminated on a substrate layer comprising at least one material chosen from a non-woven material, a woven-or a knitted fabric, a synthetic resin film and a synthetic resin film reinforced with fabric or paper, is used, and a granular swellable clay is strewn on this laminate, and the laminate is incorporated through needle punching, moistened and then dried.
KAARUSUTEN YOHANSEN
FUORUKARUTO MIYURAA
