中国胶粘剂

木质素作为一种经济、易获取的可再生生物资源，可部分替代苯酚生产木质素基酚醛树脂（LPF）。但替代苯酚与甲醛反应的产物大分子结构相较于纯酚醛树脂（PF）更加复杂，易发生团聚，使得LPF的储存稳定性低。为克服这一难题，本研究在LPF制备过程中添加高岭土制备高岭土-木质素基酚醛树脂（K-LPF），以储存时间和胶合特性为主要评价指标，采用正交设计法对影响K-LPF储存稳定性的主要因素进行了优化。研究结果表明：（1）添加高岭土作为胶粘剂的稳定剂，可有效提高储存稳定性。采用正交设计法确定的最佳工艺条件为：木质素替代率60%，碱用量25%，在第3批加料时加入6%的高岭土，所得胶粘剂的胶合强度为1.33 MPa，储存时间可达98 d，且各项指标均能满足GB/T 14732—2017标准中的要求。极差分析表明，影响储存时间的主要因素的主次顺序为：碱用量>木质素替代率>高岭土添加量>高岭土添加批次。（2）红外光谱（FT-IR）和热重分析（TG）结果表明，添加高岭土制备的K-LPF与LPF和PF红外谱图类似，均具有相近的结构，表明高岭土和木质素以共聚的方式与苯酚和甲醛参与反应，降低胶粘剂中有机大分子因自聚而发生的沉淀，提高其储存稳定性。（3）验证试验表明，实际试验结果符合正交设计法的预测，进一步证明了以上优化所得最佳工艺条件的有效性和可靠性，为制备储存稳定性高的K-LPF提供了理论和实践依据。

Lignin,as an economical,easily accessible,and renewable bio-resource,can partially replace phenol in the production of lignin-based phenolic resin(LPF). However,the macromolecular structure of the product from the reaction between substituted phenol and formaldehyde is more complex compared to pure phenolic resin(PF),leading to easy agglomeration and low storage stability of LPF.In order to address this challenge,kaolin was added during the preparation of LPF to develop kaolin-lignin-based phenolic resin(K-LPF). Using storage time and bonding properties as main evaluation indicators,the orthogonal design method was employed to optimize the main factors affecting the storage stability of K-LPF. The research results showed that,(1) The addition of kaolin as a stabilizer of adhesive effectively enhanced the storage stability. The optimal process conditions determined by orthogonal design method were:lignin substitution rate of 60%,alkali dosage of 25%,and addition of 6% kaolin during the third batch of feeding.The bonding strength of the adhesive obtained was 1.33 MPa,and the storage time could reach 98 days,with all indicators meeting the requirements of GB/T 14732—2017 standard.The range analysis revealed that the main factors affecting storage stability followed the order:alkali dosage > lignin substitution rate > kaolin addition amount > kaolin feeding batch.(2) Infrared spectroscopy(FT-IR) and thermogravimetric(TG) analysis indicated that the K-LPF prepared by adding kaolin had similar structures to LPF and PF in infrared spectra,suggesting that kaolin and lignin participated in the reaction with phenol and formaldehyde through copolymerization. It reduced the precipitation of organic macromolecules caused by selfpolymerization,thereby improving its storage stability.(3) The verification experiment showed that the actual experimental results conformed to the prediction of orthogonal design method,further proving the effectiveness and reliability of the optimized process conditions obtained above,providing theoretical and practical basis for the preparation of K-LPF with high storage stability.