| 摘要 |
PROBLEM TO BE SOLVED: To obtain a halogen-free flame retardant capable of improving the flame retardancy of a polymer material without causing the reduction of the characteristics originally possessed by the polymer material, and hardly causing environmental problems, and further to provide a flame retardant resin composition by using the flame retardant. SOLUTION: This halogen-free flame retardant is a high-ortho novolak resin having 5,000-50,000 weight average molecular weight and >=55% bond at the ortho-ortho position in the whole methylene bond in the novolak type phenol resin obtained by subjecting trihydric phenols and aldehydes to additional condensation reaction.
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