| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a novolac type phenol resin which has little content of dimers of phenols and is capable of obtaining a novolac type phenol resin having a large weight-average molecular weight and a high softening point in a high yield. <P>SOLUTION: The method for producing a novolac type phenol resin has a first step in which a novolac type phenol resin is obtained by heterogeneously reacting phenols and aldehydes in the presence of 5 pts.mass or more of phosphoric acids against 100 pts.mass of the phenols, and a second step in which the phenol resin is dissolved by adding a non-reactive organic solvent into the reaction system and is further allowed to be reacted with the aldehydes. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
