摘要 |
The invention relates to a process for the preparation of resols by reacting phenolic compounds with aldehydes with catalysis by metal salts whose cation can easily be precipitated as low-solubility salts in industrial processes. In this process, a dispersant is added to the reaction mixture comprising phenolic compound, aldehyde and metal salt before, during or after the condensation reaction, and a complexing agent is admixed after the condensation reaction is complete and after the dispersant has been admixed. The resultant resins are transparent even after neutralization using sulphuric acid. |