低游离甲醛羟甲基化木质素磺酸盐-酚醛复合胶黏剂研究

Study on Composite Adhesive of Hydroxymethylated Lignosulfonate/Phenol-formaldehyde Resin with Low Free Formaldehyde

以工业木质素为原料,采用羟甲基化反应提高木质素反应活性,确定了羟甲基化反应木质素和催化剂的最佳配比:木质素与甲醛质量比为3∶1、催化剂用量为0.25%(以木质素原料计),并用FT-IR和13C NMR对羟甲基化反应结果进行了分析。通过羟甲基化木质素磺酸盐(HLF)与酚醛树脂(PF)共混制得木质素酚醛树脂(LPF)胶黏剂。实验结果表明,该胶具有制备工艺简单、游离甲醛低的特点,用HLF替代40%的PF时,其胶合强度达到国家Ⅰ类胶合板的要求。

The lignin-phenol-formaldehyde resin adhesive was prepared by blending modified technical lignin with phenol-formaldehyde resin, Lignin was modified by hydroxymethylation to increase reactivity and the resulted hydroxymethylated lignin was analyzed hy FT-IR and ^13C NMR. The optimal conditions of hydroxymethylation are as follows： lignin-formaldehyde mass ratio 3 ： 1, catalyst dosage 0.25 %. When 40 % of phenol-formaldehyde resin （ PF ） was replaced by hydroxymethylated lignin, the adhesive thus formulated showed low free formaldehyde, and the bonding strength could meet the standard of type I plywood.