| 摘要 |
PURPOSE:To obtain a filter medium excellent in heat resistance, fire retardancy and chemical resistance, hardly causing clogging and having a long life by coating a nonwoven fabric or felt composed of fibers of a polyimide resin having a repeated unit represented by the specific general formula with a meltable fluoroplastic, etc. CONSTITUTION:A highly heat-resistant filter medium used in an incinerator of industrial or municipal solid waste is formed by coating a nonwoven fabric or felt composed of fibers of a polyimide having a repeated unit represented by the general formula (wherein n is an integer of 1 or more, x is a tetravalent aromatic group and R is at least one kind of a divalent aromatic group) with a meltable fluoroplastic or a solvent soluble room temp. curable fluoroplastic or a fluoroelastomer. This filter medium is produced, for example, by applying a dispersion prepared by dispersing a fine powder of the meltable fluoroplastic in water or an org. solvent to the nonwoven fabric or felt composed of the polyimide fibers and heating the coated nonwoven fabric or felt to 200-400 deg.C. |
