摘要
为解决三聚氰胺甲醛浸渍胶膜纸脆性大、饰面胶合板龟裂问题,以二乙二醇(diethylene glycol,DG)和纳米二氧化硅(nano-silicon dioxide,NS)为改性剂对三聚氰胺-甲醛(melamine-formaldehyde,MF)浸渍树脂进行改性,并制备了浸渍胶膜纸和饰面胶合板。对MF树脂的化学结构变化、热稳定性能及浸渍胶膜纸的抗张性能、饰面板的表面性能进行了分析测试,得出以下结论:加入DG和NS可提高MF树脂的黏度和固体含量,改性后MF树脂的化学结构发生变化,与改性剂之间发生了化学结合;改性后树脂的初始热解温度略有下降,但最大失重速率温度仍在370℃以上,热稳定性高。当DG添加量为8.0%、NS添加量为2.5%时,纸张抗张强度从MF的2.40 MPa提高至MFDGNS_(5)的4.41 MPa,提高幅度明显,当NS添加量为1.0%时,纸张断裂伸长率从MF的2.86%提高至MFDGNS_(2)的4.71%,提高幅度达64.69%;当NS添加量为1.0%和1.5%时,浸渍胶膜纸卷曲的最小曲率半径为7.5 mm,远小于MF树脂浸渍胶膜纸的12.5 mm,这个结果与断裂伸长率的趋势一致。当NS的添加量为1.5%时,浸渍胶膜纸饰面胶合板的磨耗值最低可达到46 mg/(100 r),无露底现象,表面胶合强度最高达到1.50 MPa;当NS添加量为1.0%和1.5%时,浸渍胶膜纸饰面胶合板的耐龟裂等级为4级。利用DG和NS改性MF树脂具有一定的增韧效果,可以防止饰面胶合板龟裂。
Melamine-formaldehyde(MF)resin,widely used in impregnated film paper decorative panels,offers several advantages,including excellent water resistance,strong bonding properties,fast curing speed,and a colorless,transparent appearance after curing.However,due to the rigid triazine ring structure of MF resin,the high cross-linking density after curing significantly limits the movement between molecular chains,reducing its ability to absorb and disperse external stress.This leads to the increased brittleness in impregnated film paper.When used for plywood and wood-based composites,MF resin is prone to cracking due to its inability to accommodate the size changes caused by variations in the moisture content of the substrate.To solve the problems,MF resin was modified with diethylene glycol(DG)and nano-silicon dioxide(NS)as moderators and impregnated film paper and veneer plywood were prepared in this study.The chemical structure and thermal stability of MF resin,the tensile properties of impregnated film paper and the surface properties of decorative panels were tested.The following conclusions were draw:the addition of DG and NS increased the viscosity and solid content of the MF resin,and the chemical structure of MF resin changed after the modification,and chemical binding occurred between MF resin and modifier.The initial pyrolysis temperature of the modified resin decreased slightly,but the maximum weight loss rate temperature remained above 370℃,and the thermal stability was high.When the content of DG was 8.0%and the content of NS was 2.5%,the tensile strength of paper increased significantly from 2.40 MPa for MF to 4.41 MPa for MFDGNS_(5).When the content of NS was 1.0%,the elongation at break of paper increased from 2.86%for MF to 4.71%for MFDGNS_(2),whose increase rate was 64.69%.When NS contents were 1.0%and 1.5%,the minimum curvature radius of the crimp of the impregnated film paper was 7.5 mm,which was much smaller than that of MF resin impregnated film paper(12.5 mm),being consistent with the trend of elongation at break.When the content of NS was 1.5%,the wear value of impregnated film paper/veneer plywood reached the lowest value of 46 mg/(100 r),no bottom phenomenon,and the surface bonding strength reached the highest value of 1.50 MPa.When the NS additions were 1.0%and 1.5%,the cracking resistance level of impregnated film paper/veneer plywood was Level 4.The MF resin modified by DG and NS has the toughened properties and can prevent cracking of plywood.
作者
胡恒
刘如
龙玲
孙玉慧
HU Heng;LIU Ru;LONG Ling;SUN Yuhui(Research Institute of Wood Industry,Chinese Academy of Forestry,Beijing 100091,China)
出处
《林业工程学报》
北大核心
2025年第3期39-45,共7页
Journal of Forestry Engineering
基金
广西科技重大专项(桂科AA23062010)。
关键词
三聚氰胺甲醛树脂
二乙二醇
纳米二氧化硅
增韧防开裂改性
饰面胶合板
melamine-formaldehyde resin
diethylene glycol
nano-silicon dioxide
toughening anti-cracking modification
veneer plywood
