| 摘要 |
PURPOSE:A phenolic foam, obtained by expanding a phenolic resin prepared by uniformly incorporating a high-ortho novolak resin with a resol resin, and having remarkably improved strength. CONSTITUTION:A phenolic foam obtained by incorporating (A) a high-ortho novolak resin, prepared by reacting phenol (preferably unsubstituted) with formaldehyde (preferably paraformaldehyde and formalin together) preferably at 1: 0.5-1:1.5 molar ratio in the presence of a weakly acidic catalyst under refluxing, dehydrating the reaction mixture under reduced pressure, and condensing the reactants at >=100 deg.C, and having preferably >=69% combined ortho content and 400-1,000 number-average molecular weight with (B) a resol resin, prepared by condensing phenol with an aldehyde preferably at 1:1-1:3 molar ratio in the presence of an alkaline catalyst, and containing preferably little free phenol and moisture at 1:20-20:1 solid weight ratio between the components (A) and (B), adding an acidic curing agent, foaming agent, etc. thereto, mixing them, casting the resultant mixture into a vessel, and heating, expanding and curing the mixture.
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