| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing an adhesive for wood, keeping the productivity equal to an amino-based resin adhesive, and simultaneously giving a wooden board satisfying the E-O grade of an emitted amount of formaldehyde according to JIS, while the grade cannot be achieved by use of the amino-based adhesive. SOLUTION: This method for producing a phenolic resin adhesive comprises subjecting phenols to condensation reaction with aldehydes in the presence of a base catalyst, wherein the first step reaction is carried out so that formaldehyde is reacted with phenol in a formaldehyde/phenol mol ratio of 2.0-3.0, then the second step reaction is carried out so that the phenol, or the phenol and the formaldehyde, is added to the reaction mixture to decrease the mol ratio to 1.2-1.8 by application of a calcium compound as a catalyst.
|
