Brief description of the equalization of the amplitude / frequency response of a transducer assembly electro - acoustic transducer assembly corresponding

摘要

PCT No. PCT/FR87/00491 Sec. 371 Date Aug. 22, 1988 Sec. 102(e) Date Aug. 22, 1988 PCT Filed Dec. 10, 1987 PCT Pub. No. WO88/04295 PCT Pub. Date Jun. 16, 1988.This invention relates to novel furan polyols, which are characterized in that they are the product of reaction of a strain selected from the group or consisting of a polyalcohol, a monoamine or polyamine, said polyalcohol or said amine possibly containing a furan cycle and mixtures thereof with a chain extension agent constituted by an organic epoxide, with the proviso that this organic epoxide is a furannic oxiran when this polyalcohol does not contain a furan cycle with the exclusion of 2,5(bis-hydroxy)furan as sole strain, when the chain extension agent does not contain any furan cycle. These furan polyols are used for the preparation of polyurethane foams having improved properties.