Sealing mat for below-ground construction and civil engineering has outer woven or nonwoven layers with an intermediate bonded tangled mass containing lodged swelling materials to give the required sealing and strength at a low cost

摘要

The sealing mat has outer layers (1,2) of a woven or nonwoven material with a swelling material (3) between them. A tangled mass (4) is between the outer layers (1,2), of hardened plastics filaments in an even distribution, firmly bonded to the outer layers (1,2). The swelling material (3) is lodged within the tangled mass (4). The tangled mass (4) is bonded to the outer layers (1,2) by welding or an adhesive, firmly enough to remain bonded when the lodged material (3) swells. The plastics filaments are produced by extrusion. The swelling material (3) is in a powder or granulate form, using bentonite. An Independent claim is included for a sealing mat production process where the tangled mass (4) is produced by an extruder and, before the filaments have hardened, they are worked by distance rollers to give a constant thickness. The tangled mass (4) is bonded by welding or an adhesive to one side of an outer layer (1). The swelling material (3) is lodged within the tangled mass, and it is bonded to one side of a second outer layer (2) by a pressure roller and an adhesive for the bonding. Preferred Features: The adhesive is preferably a thick layer adhesive and especially a bitumen-latex adhesive. The distribution of the swelling material (3) is by vibration or pressing to control the ratio of the filled and unfilled zones within the tangled mass.