| 摘要 |
PROBLEM TO BE SOLVED: To provide an adhesive composition having a long pot life by, in preparation of the adhesive composition comprising a resorcin formaldehyde condensate and a rubber latex, carrying out a condensation reaction of resorcin with formaldehyde at a specific pH and then lowering the pH. SOLUTION: A condensation reaction of resorcin with formaldehyde is carried out at a pH of at least 7.5, preferably pH of 8.5-9.7, and then the pH is lowered preferably to 4.0-7.5, further preferably 5.0-6.7. The condensation reaction of resorcin with formaldehyde is a reaction forming a resol, and is preferably carried out in the presence of a rubber latex. A method of lowering pH of the reaction system after the condensation reaction is preferably conducted by using an ion exchange, or adding an acid or an acid salt. A formulation ingredient of an adhesive composition preferably comprises a solid content of a resorcin formaldehyde condensate of 7-250 pts.wt. to 100 pts.wt. of a solid content of the rubber latex.
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