| abstract |
To a first organic liquid which has dissolved therein a fluorocarbon polymer e.g. 5 to 50% w/w e.g. PVDF, is added a second, compatible, non-solvent organic liquid in an amount (e.g. 1-50%) w/w such as to leave the polymer in solution. The mixed solution is applied to a structural, leatherlike or (especially) fabric substrate and heated e.g. at 60° to 150° for 2 - 15 minutes. Polymer departs as the first liquid evaporates and pores form therein as the second liquid evaporates from the deposit. The anchored layer produced repels liquid water but allows passage of water vapour. |