| 摘要 |
<p>Diffusion permeable, watertight roof felt comprising a min. three-layer composite contains (A) outer thermoplastic nonwoven layers, and (B) inner porous thermoplastic film layer Pref. (B) is a breathable film with a thickness of 10-50 microns and contg. at least 10 (20-55) wt.% inert inorganic solid filler particles less than 100 (0.5-20) microns in diameter. The filler particles are CaCO3. (B) is made porous by punching holes in it or needling. The thermoplastic for (B) is a polyolefin, pref. polyethylene. The basis wt. of (B) is 10-40 g/m<2>. Hydrophobic agents based on fluorocarbons, eg. perfluoroalkyl acrylate block copolymers or fluorocarbons contg. trifluoromethylsilyl gps. instead of perfluoroalkyl gps., are used to make (B) hydrophobic. The nonwoven layer (A1) on the building side comprises endless filaments and has a basis wt. of 17-120 (20-80) g/m<2>, whilst the nonwoven layer (A2) on the roof side also comprises endless filaments and had a basis wt. of 20-120 (50-120) g/m<2>. (A) comprise polyolefins, pref. polypropylene. (A) may comprise endless polyester filaments and have a basis wt. of 30-120 g/m<2>.</p> |
