造纸黑液木质素用于制备人造板胶粘剂的研究

Study on plywood adhesive preparation with lignin from pulping black liquor

分别采用硫酸、硝酸和盐酸从造纸黑液中提取木质素,以此替代部分苯酚,制备改性人造板用酚醛树脂胶粘剂,并测定其固体含量、动力黏度(40℃)、游离甲醛含量和胶合强度等性能;考察了3种酸析木质素掺入量、催化剂(氢氧化钠)加入量和苯酚与甲醛摩尔比(简称酚醛比)对木质素酚醛树脂胶粘剂性能的影响。结果表明,当硫酸、硝酸木质素掺入量为苯酚用量的20%(质量分数,下同)时,获得的胶粘剂性能较好;以硝酸木质素掺入量为苯酚用量的20%为例,当氢氧化钠加入量为苯酚用量的0.6%(质量分数)、酚醛比为1.0∶1.5时,制备的硝酸木质素酚醛树脂胶粘剂胶合性能较好。用木质素替代部分苯酚,不仅可以降低产品成本,而且减少了苯酚的用量,更环保。

Lignin-phenol-formaldehyde adhesives were prepared by using the acid separated lignin as raw materials to partially replace phenol. Three acids, sulfate acid, nitrate acid and hydrochloride acid, were used respectively to extract lignin from the black liquor. The properties of the above adhesives were determined, such as solid content, dynamic viscosity（40 ℃ ）, free formaldehyde content and glue strength. The effects were studied on lignin content, catalytic content and the ratio of phenol to formaldehyde for lignin-phenol-formaldehyde adhesives. As a result, when the addition of above three lignins was 20%, the properties of adhesives were preferable. For example, by adding 20% lignin nitrate, when catalytic content was 0.6%, the ratio of phenol to formaldehyde was 1.0 ： 1.5, the promising properties of adhesive were obtained. Using lignin to partially replace phenol not only can decrease production costs, but also is desirable for environmental protection.