Ageing-resistant sealing sheet

A highly aging-resistant flat sheet for the construction sector, the flat sheet comprising:

• a multilayer structure comprising at least a first nonwoven layer and a second nonwoven layer;
• and
• at least one membrane layer arranged between the first nonwoven layer and the second nonwoven layer, the membrane layer being in the form of a monolithic membrane layer and comprising a thermoplastic elastomer selected from the group consisting of thermoplastic polyurethanes and/or thermoplastic copolyesters (TPEE);
• wherein the first and/or the second nonwoven layer having a weight per unit area of between 10 and 150 g/m2;
• wherein the first nonwoven layer and the second nonwoven layer are formed as a monocomponent fiber nonwoven;
• wherein the material of the monocomponent fiber is selected from the group of polyolefin homopolymers, polyolefin copolymers and their blends and/or mixtures;
• wherein an adhesion promoter layer is arranged between the first and the second nonwoven layer and the membrane layer;
• wherein the adhesion promoter layer is formed by a reactive polyurethane hot melt adhesive and is applied with a weight per unit area of 2 to 20 g/m2;
• wherein the sheet has an aging stability of at least 25 years;
• wherein the aging stability is determined by subjecting the sheet to an artificial aging process, wherein the artificial aging process is carried out at a temperature of 70±2° C. and an air velocity of 5±2 m/s;
• wherein the artificial aging process for determining the aging stability is carried out over a period of at least 36 weeks;
• wherein the time in weeks for performing the artificial aging process is determined by multiplying the number of years for aging stability by a factor of 12 and dividing the obtained product by a value of 4.5, and/or by multiplying the number of years for aging stability by a factor of 2.5;
• and
• wherein, following the artificial aging process, the water resistance of the sheet is tested in accordance with DIN EN 13859-1-2010-11, section 5.2.3, against a water column of at least 200 mm over a period of 2 h.