高替代率竹焦油酚醛树脂的合成工艺研究

竹焦油是竹炭产业的副产物之一,富含酚类物质,可部分替代昂贵苯酚合成竹焦油酚醛树脂(BPF)。以n(苯酚)/n(甲醛)、竹焦油替代率、n(NaOH)/n(苯酚)和反应时间为试验因素,以BPF的黏度和游离酚含量、相应胶合板的胶接强度和甲醛释放量为考核指标,采用正交试验法优选合成高替代率环保型BPF的最佳工艺条件。结果表明:当n(苯酚)/n(甲醛)=2.0、竹焦油替代率为50%、n(NaOH)/n(苯酚)=0.35和反应时间为60 min时,由BPF胶粘剂压制而成的胶合板,其胶接强度和甲醛释放量分别达到GB/T 9846.3—2004标准中Ⅰ类胶合板和E0级的指标要求。

Study on synthesis process of bamboo-tar phenolic resin with high substitution rate

A BPF(bamboo-tar phenolic resin) was prepared with bamboo-tar as substitute of part expensive phenol because there were rich phenolic compounds in bamboo-tar,which is a byproduct of bamboo charcoal industry.With molar ratio of n(phenol)/n(formaldehyde),mass substitution rate of m(bamboo-tar)/m(total phenol),molar ratio of n(NaOH)/n(phenol) and reaction time as experiment factors,with viscosity and free-hydroxybenzene content,bonding strength and formaldehyde emission of corresponding plywood as evaluation indices,the optimal process conditions of preparing environment-friendly BPF with high substitution rate were preferred by orthogonal experiment.The results showed that the bonding strength or formaldehyde emission of plywood,which was pressed by BPF adhesive,could reach index requirement of I type plywood or E0 level respectively in GB/T 9846.3—2004 standard when n(phenol)/n(formaldehyde) and n(NaOH)/n(phenol) were 2.0 and 0.35 respectively,mass substitution rate of m(bamboo-tar)/m(total phenol) was 50% and reaction time was 60 min.