| 摘要 |
PROBLEM TO BE SOLVED: To obtain a nonwoven fabric of blended yarn suitable for an air filter, low in pressure drop, excellent in balance between collecting efficiency and ventilation resistance, excellent in bulkiness, by subjecting a specific nonwoven fabric of blended yarn (mixed yarn) to electret treatment, heat- treating in a fixed temperature range to develop crimping. SOLUTION: A nonwoven fabric of blended yarn comprising one or more polyolefin yarns (preferably 0.5-10μm average fiber diameter) and one or more fluorine-based polymer yarns (preferably 3-85wt.% content) obtained by mutually blending fibers composed of two or more materials different in ratio of relative dielectric constant to conductivity, having 10-200g/m<2> weight is subjected to electret treatment and crimping is developed by heat treatment at 50-130 deg.C to give the objective nonwoven fabric. Preferably, the nonwoven fabric comprises 3-45wt.% of yarn having crimping properties. |
