Roof lining material is in layers with a center adhesive layer and a woven support layer to give a variable steam permeability according to the relative air humidity and prevent summer condensation

摘要

The web of roof lining material (11) has an open polymer diffusion layer (1), a second partially-open diffusion layer (2) and a third open polymer diffusion layer (3). The partially-open diffusion layer (2) is an adhesive layer between the flanking layers (1,3) with, in the dry zone, a steam diffusion resistance equivalent to an air layer thickness of 0.05-0.5 m, and a steam diffusion resistance in the wet zone equivalent to an air layer thickness of 0.005-0.2 m or 0.05-0.2 m. The first polymer layer (1) is of polyethylene (PE), polypropylene (PP) or polyester, or polyester with an additive of polyamide (PA) or wholly of PA. The first layer (1) is a shear-resistant felt. The second, adhesive layer (2), is a PE copolymer with acrylic acid and/or their derivatives, or of ethylene vinyl acetate (EVA) or PA and they can encapsulate CaCO3. The EVA adhesive layer (2) has a vinyl acetate content of 6-38%. The adhesive layer (2) becomes fluid at a temp. of 70-90 deg C and especially from 80 deg C. The adhesive layer (2) contains flame resistant additives with a phosphor and/or nitrogen base and/or a base of ammonium polyphosphate and triazene. The material (11) can also have a fourth layer, identical to the adhesive layer (2), and a fifth layer identical to the first layer (1). The third layer (3) has a material weight of 50-400 g/m2 or 100-150 g/m2. The first (1) and fifth layers have a material weight of 15-30 g/m2. An acrylate adhesive strip is applied to at least one side edge and/or a longitudinal edge at the upper and/or lower sides. The material has an additional layer (6) of a supporting woven fabric, in a leno weave or a rectangular grid netting, of twisted filaments of polyethylene terephthalate (PET), PE or PP woven at right angles to each other. The supporting weave (6) is between one of the layers.