【摘要】 针对脲醛树脂耐水、耐候性能差和潜在甲醛释放的问题，以工业碱木质素（L）为原料，通过与苯酚（P）、尿素（U）和甲醛（F）共缩聚反应制备了符合E_NF级Ⅰ类胶合板要求的木质素基胶黏剂（LPUs）。考察了L、P和U质量比对LPUs凝胶时间、游离甲醛含量、储存稳定性、固化反应活性以及胶合板理化性能的影响。结果表明：m_L/（m_P+m_U）为1∶1时制备的树脂LPU1～LPU4中，随着尿素用量的增加，LPUs树脂的凝胶时间逐渐缩短，m（P）∶m（U）=30∶70时制备的LPU4,其凝胶时间为（18±2） min,约为LPU1（m（P）∶m（U）=90∶10）的凝胶时间（30±2） min的40%,游离甲醛含量从0.05%（LPU1）升高至0.18%,储存期由127 d缩短至14 d,表现出脲醛树脂的理化特性。DSC监测固化过程焓变行为表明，LPUs树脂反应活化能仅为商业酚醛树脂和脲醛树脂的2%～7.8%。m_L/（m_P+m_U）=1且苯酚用量不低于尿素时制备的LPU1～LPU3树脂胶合板耐沸水胶合强度和甲醛释放量满足E_NF级Ⅰ类胶合板要求，其中LPU2树脂的施胶量可降低至工业生产工艺的66.7%,此时，依然可以确保胶合板的耐沸水胶合强度和甲醛释放量满足E_NF级Ⅰ类要求，可有效降低胶合板生产成本。更多还原

【Abstract】 In order to address the problems of water resistance, poor weather resistance and potential formaldehyde release of urea-formaldehyde resins, lignin-based adhesives（LPUs） with ultra-low formaldehyde emission meeting the requirements of E_NF grade Ⅰ plywood were prepared by co-condensation with phenol（P）, urea（U） and industrial alkali lignin（L）. The effects of L, P and U mass ratio on the gel time, free formaldehyde content, storage stability, curing reaction activity and physicochemical properties of LPUs were investigated. The results showed that the maximum ratio of m_L/（m_P+m_U） was up to 1 ∶1. With the decreasing mass ratio of P and U, the gel time of LPUs resin was gradually shortened by 40%, the free formaldehyde content increased from 0.05% to 0.18%, and the storage period was reduced from 127 d to 14 d, showing the physical and chemical properties of urea-formaldehyde resins. The enthalpy change behavior of the curing process monitored by DSC showed that the reaction activation energy of LPUs resin only reached 2%-7.8% of that of commercial phenolic and urea-formaldehyde resins. The boiling water resistance and formaldehyde emission of LPU1-LPU4 resin plywood prepared with m_L/（m_P+m_U）=1 and with the amount of phenol not less than that of urea, met the requirements of E_NF grade Ⅰ plywood. The glue spread of LPU2 resin could be reduced to 66.7% compared to that of the industrial production process. At this time, the boiling water resistance and formaldehyde emission of plywood could still be ensured to meet the requirements of E_NF grade Ⅰ, which could effectively reduce the production cost of plywood.更多还原