| 摘要 |
PURPOSE:To obtain a polyurethane foam having good air permeability, by applying an org. solvent to an open-cell non-rigid, polyurethane foam sheet and simultaneously blowing compressed air thereon to remove cell membranes. CONSTITUTION:An org. solvent is applied to an open-cell non-rigid polyurethane foam sheet to allow it to swell. Compressed air is blown on the swollen foam sheet to remove cell membranes. Examples of the org. solvents are halogenated hydrocarbons, aliph. hydrocarbons, arom. hydrocarbons, alcohols and ketones. They may be used either alone or as a mixture thereof. Low-boiling halogenated hydrocarbon solvents are particularly preferred from the viewpoints of activity and workability. According to this method, the cell membrane which is allowed to swell and made brittle by the application of the solvent can be broken and removed and hence the air permeability is improved. Further, the liquid permea bility is also improved and hence the resulting urethane foam can be used as a filter.
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