2008•Thermosetting ResinRequires access
Synthesis of novolac PF with low free phenol
Shulong Li
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Abstract
A novolac PF with low free phenol was synthesized by adding an organic acid A which changed the traditional technology.The effect of molar ratio of phenol to formaldehyde and the content of organic acid A on soften point of resin was investiged.The influence of reaction temperature and time on free phenol in the product was also studied.The optimum conditions were as followed: the first step reaction temperature 98～104 ℃,reaction time1h,the amount of catalyst hydrochloric acid 1.0%(based on phenol mass),the molar ratio of phenol to formaldehyde to organic acid A 1:0.82:0.02 and the second step reaction temperature180 ℃,reaction time was 1.5 h.Free phenol of synthesized novolac PF decreased from 5%-10%to 0.55% detected by gas chromatography.