| abstract |
Oligomeric formal diols are prepared by coupling formaldehyde to segments of poly (tetramethylene ether) glycols, each of which has a molecular weight of between 650 and 3000, in the presence of a granulated acid catalyst, and in order to obtain poly ( tetramethylene ether) formal glycols whose molecular weight is between 1400 and 12,000. It is also possible to prepare formal oligomeric diols of a second type by coupling formaldehyde segments of poly (tetramethylene ether) glycols, mixed with segments of other polymeric glycols such as polyethylene oxide glycol whose molecular weight is 200, in order to obtain poly (ether formal) glycols whose molecular weight is significantly higher than that of either of the initial polyether glycols , and whose properties are significantly different from those of the polyether glycol generators, and can influence the behavior, as soft segments or elastomers of polyurethanes, polyether derivatives and polyureas. In addition, a third type of oligomeric formal diol can be prepared by coupling formaldehyde with monomeric diols, for example 1,4-butanediol, in order to obtain higher molecular weight poly (oxybutylene formal) glycols. |