| 摘要 |
<p>This refrigerating machine oil comprises esters of a polyhydric alcohol with fatty acids. In the fatty acids, the molar ratio of C4-6 fatty acids to branched C7-9 fatty acids is 15:85 to 90:10, and the C4-6 fatty acids contain 2-methylpropanoic acid, with the sum total of the C4-6 fatty acids and the branched C7-9 fatty acids accounting for at least 20mol% of the whole of the fatty acids constituting the esters. This working fluid composition for refrigerating machines comprises the refrigerating machine oil and a difluoromethane refrigerant and/or an unsaturated fluorinated hydrocarbon refrigerant. This refrigerating machine oil comprises esters of a polyhydric alcohol with fatty acids. In the fatty acids, the molar ratio of C4-6 fatty acids to branched C7-9 fatty acids is 15:85 to 90:10, and the C4-6 fatty acids contain 2-methylpropanoic acid, with the sum total of the C4-6 fatty acids and the branched C7-9 fatty acids accounting for at least 20mol% of the whole of the fatty acids constituting the esters. This working fluid composition for refrigerating machines comprises the refrigerating machine oil and a difluoromethane refrigerant and/or an unsaturated fluorinated hydrocarbon refrigerant. One embodiment pertains to a filter for masks obtained by folding moist nonwoven fabric of synthetic fiber in concentric pleats. Said synthetic fiber comprises 10-50 mass% of short fibers A with fiber diameter in the range of 100-1000 nm and fiber length in the range of 0.1-1 mm; and also comprises binder fibers B with fiber diameter in the range of 6-15 μm and fiber length in the range of 5-10 mm, and fibers C with fiber diameter and fiber length larger than the short fibers A and fiber diameter and fiber length smaller than the binder fibers B.</p> |
