| 摘要 |
A phenolic material having improved cell structure and surface skin characteristics is prepared by mixing, foaming and curing a foamable composition comprising a phenol-formaldehyde resin; an acid catalyst; a foaming agent-mixture containing a low boiling fluorocarbon, a surface active agent and a polyhydric alcohol; and a filler/extender mixture functioning as a cell structure control agent comprised of a water soluble inorganic salt and ammonium lignin sulfonate.
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