尿素改性热塑性酚醛树脂的合成及应用

Synthesis and Application of Urea-modified Novolak Phenolic Resin

先用尿素、甲醛合成二羟甲脲 ,然后在酸性介质下把二羟甲脲滴加在苯酚中反应合成尿素改性的热塑性酚醛树脂。研究了反应浑浊点和二羟甲脲的滴加速度 ;同时研究了二羟甲脲与苯酚的尿酚比与物料的出料温度、产品产率及树脂理化性能指标的关系。结果表明 :①二羟甲脲滴加速度的合适范围是 0 0 12～ 0 0 2 9mol/mol·min ;②本树脂的出料温度为12 5℃以下 ;③产品收率、游离酚、软化点随尿酚比的增长而递增 ,凝胶速度变化不大。

s Dihydroxymethyl urea was synthesized with urea and formaldehyde and then dropped in phenol under acidic condition to synthesize urea modified novolak phenolic resin.The effects of turbidity point of the reaction,the dropping rate of dihydroxymethyl and the molar ratio of urea to phenol on the final temperature during the process,reaction yield and chemical and physical properties of the resin were studied.The results showed the dropping rate range of dihydroxymethyl urea should be 0.012～0.029 mol/mol.min;the final temperature during drying process would better to be 125℃;the reaction yield,free phenol and softening point of the resin increased with the increase of the molar ra tio of urea to phenol,with little change in the curing rate of the resin.The application of the prepared resin to phenolic molding compound was also introduced in this paper.