| 摘要 |
Phenolic resoles are provided which are free of ionic species capable of being removed by the free acid form of a cation exchange resin and the free base form of an anion exchange resin. The deionized resoles of the invention have extended shelf-life due to their enhanced inherent stability towards self-condensation under otherwise adverse aging conditions. Notwithstanding their extended shelf-life, the resoles of the invention have excellent reactivity as foamable compositions, and are used with particular advantage for the formation of cellular phenolic resins. Also provided is a method for producing phenolic resoles having the aforementioned characteristics which comprises treatment of alkaline metal catalyzed condensates of a phenol and an aldehyde with cation and anion exchange resins in their respective free acid and free base forms. |
