A cured phenolic resin may be prepared by reacting (1) an esterified phenolic compound containing one or more phenolic hydroxyl groups and/or one or more esterified phenolic hydroxyl groups and further containing one or more esterified methylol groups positioned ortho and/or para to a phenolic hydroxyl group or esterified phenolic hydroxyl group with (2) a phenolic novolak resin in the presence of a base and water or other polar solvent. The invention is particularly useful for the production of foundry moulds or cores wherein the above composition is used as a binder for a granular refractory material such as sand.
固化
酚醛
树脂的制备方法是:(1)含有一个或多个
酚羟基和/或一个或多个
酯化
酚羟基并进一步含有一个或多个与
酚羟基或
酯化
酚羟基正交和/或对位的
酯化
甲醇基的
酯化
酚化合物与(2)
酚醛新
戊二烯树脂在碱和
水或其他极性溶剂存在下反应。本发明特别适用于生产铸造模具或芯模,其中上述组合物用作砂等颗粒状耐火材料的粘结剂。