| 摘要 |
<p>Prepn. of water-soluble condensates comprises heating a mixt. of HCHO, an alkali (metal) (bi)sulphite and a phenolic material; adding H2O during the reaction in an amt. sufficient to keep the mixt. in a fluid state but insufficient to stop the reaction; and then adding sufficient H2O to stop the reaction before the prod. becomes insoluble in H2O. The phenolic material comprises phenol, a cresol, a xylenol, resorcinol, or tar acids. The condensates can be used to prepare additives for controlling the dispersion and/or fluid loss properties of clay-based drilling fluids as described in the Parent Patent.</p> |
