Vapour-permeable building foil prodn., esp. for roof sarking

摘要

The prodn. of vapour-permeable building foil (I) for insulation, esp. sarking strips for covering roofs with heat-insulation between the rafters, comprises bonding together at least two strips of fibre-based material (II) with a layer of water vapour-permeable polyurethane (PU) (III). Also claimed is foil (I) in which the PU is a 3-component copolymer of (a) a polyol mixt. contg. polyethylene glycol (PEG) or PEG copolymer and polypropylene glycol (PPG) and/or polytetramethylene glycol (PTG) and/or polycaprolactone (PCL) and/or polycarbonate (PC) and/or polyadipate, (b) MDI and (c) chain extender(s).