| 摘要 |
PURPOSE: To improve steam permeability by consolidating, with a meltable binder, the spunbonded fabric of filament of polyethylene terephthalate embedded in a bitumen matrix. CONSTITUTION: A roofing underfelt is formed from the spunbonded fabric of filament of polyethylene terephthalate having filament linear density 1-8 dtex which is embedded in a bitumen matrix. Here, the weight of bitumen is 40-90% of underfelt's basic weight while that of spunbonded fabric being 10-60%. The spunbonded fabric is consolidated with a meltable binder whose melting point is 150-180 deg.C which is lower than the working temperature for bitumen and which exists in the spunbonded fabric by 5-20% of total weight. Further, the spunbonded fabric is preferred to be 50-250 g/m<2> of basic weight (80-120 g/m<2> is preferred), 0.2-0.6 mm in thickness (0.25-0.4 mm is preferred), and 20-40% in expansion coefficient. |
