| 摘要 |
PURPOSE:To obtain the subject porous film or sheet by extracting filler, atactic polypropylene, ethylene-propylene rubber and/or polyethylene from film or sheet comprising specific soft polypropylene. CONSTITUTION:Atactic polypropylene, ethylene-propylene rubber (containing polyethylene) and/or polyethylene is extracted from film or sheet composed of (A) 40-100wt.% soft homopolypropylene or soft blocked polypropylene and (B) 60-0wt.% water-soluble organic filler with a slightly polar solvent and the filler is extracted with water, or the extraction process is performed in a reverse turn to afford the aimed porous film or sheet containing many fine pores having <=1.2mum diameter and 0.6-0.9mum averaged diameter, or containing the fine pores and further pores having 3-30mum diameter. |
