HEAT-RESISTANT FILTER MATERIAL AND METHOD OF MANUFACTURE THEREOF Russian patent published in 1998 - IPC

FIELD: filter materials. SUBSTANCE: heat-resistant filter material for gases and organic liquids is made of polyimide fibers based on diaminodiphenyl oxide and dianhydride of pyromellitic or 3,3',4,4'- diphenyltetracarboxylic acid or their mixture. Manufacture of sorption-filtration material consists in electrostatic formation of microfibrous nonwoven material from solution of polymer in organic solvent followed by heat treatment, polymer being selected from the group including: polyamidoether based on bis(trialkylsilyl) ether of diaminodiphenyl oxide, where alkyl is methyl, ethyl, propyl, and isopropyl, and dianhydride of pyromellitic or 3,3',4,4'- diphenyltetracarboxylic acid or their mixture at molar ratio from 0.01:0.99 to 0.99:0.01; polyamidoacid based on diaminodiphenyl oxide and 3,3',4,4'-diphenyltetracarboxylic acid. As organic solvent, dimethylformamide or dimethylformamide-acetone mixture at volume ratio 1:(0.1-1) are used. Characteristics of material: radiation resistance not below 100 Mrad, working capacity at temperature up to 430 C and, in cryogenic temperature region, up to -196 C, insolubility in any organic solvent. EFFECT: improved working characteristics. 3 cl, 1 tbl, 7 ex