木质素改性酚醛树脂胶对耐水砂纸性能的影响

Effect of lignin modified phenolic resin adhesive on water-resistant sandpaper

为了解决耐水砂纸在生产中使用油性有机溶剂带来的环保问题,同时克服砂纸应用酚醛树脂胶黏剂时易出现脆性大等缺点,采用可再生资源木质素同时添加聚乙二醇(PEG)或聚乙烯醇(PVA)增韧剂,合成木质素改性酚醛树脂,经过乙醇稀释后制备耐水砂纸用木质素改性酚醛树脂胶、探讨其滚涂纸张制备的耐水砂纸纸基的吸水率、力学性能、磨削性能等。结果表明,采用溶剂木质素和质量分数为1.0%的PEG 600制备改性酚醛树脂胶,在合成反应时间为130 min,固化温度为160℃,固化时间为10 min时,纸基的吸水率为0.035 g/(m^(2)·s),比合成反应时间为60 min时的吸水率下降了20.45%。在反应时间为150 min而其他条件不变时,纸基的湿抗张强度最高为10.28 kN/m,Z-向抗张强度为1002.7 kPa,分别比反应时间60 min时的提高了22.23%和31.17%;同样条件下,加入质量分数为1.0%的PEG 600为增韧剂且改性树脂固含量为25%时,纸基的吸水率最低,湿抗张强度最大,Z-向抗张强度适中,分别为0.036 g/(m^(2)·s)、10.56 kN/m和886.4 kPa。用质量分数分别为0.8%和1.0%的PEG 600增韧剂改性酚醛树脂,改性树脂稀释后的固含量保持在25%~30%之间,用其处理的纸基制作砂纸,砂纸研磨标准试件铝棒,研磨时间都在30 min及以上,且砂纸无撕裂或剥落现象,均达到合格要求。

The use of oily organic solvents in the production of water-resistant sandpaper causes the environmental problems.Meanwhile,phenolic resin adhesive will result in the shortcomings such as the brittleness of sandpaper.In order to solve these problems,the lignin modified phenolic resin was synthesized by adding toughening agents of polyethylene glycol(PEG)or polyvinyl alcohol(PVA).The lignin modified phenolic resin adhesive was prepared after ethanol dilution for water-resistant sandpaper.The water absorption,the mechanical properties and the grinding properties of modified resin roll-coated paper base were investigated.The results showed that the modified phenolic resin adhesive with solvent lignin and 1.0 wt%PEG 600 is good for low water absorption.The water absorption of the paper base was 0.035 g/(m^(2)·s)with 130 min of the reaction time,160℃of the curing temperature and 10 min of the curing time.It was 20.45%lower than that of the paper base when the reaction time was 60 min.The wet tensile strength of paper base was 10.28 kN/m,and the z-direction tensile strength was 1002.7 kPa when the reaction time was 150 min.They were 22.23%and 31.17%higher than those of 60 min,respectively.Paper base showed the lowest water absorption,the highest wet tensile strength and the moderate z-direction tensile strength,when 1.0 wt%PEG 600 was added and the solid content of modified resin was 25%.Water absorption,wet tensile strength and z-direction tensile strength were 0.036 g/(m^(2)·s),10.56 kN/m and 886.4 kPa,respectively.The phenolic resins were modified by adding 0.8 wt%and 1.0 wt%PEG 600 as toughening agents.The solid content of the modified resin after dilution was kept between 25%and 30%.The sandpaper was made from the paper base treated with the modified resin,and the standard aluminum bar was ground with the sandpaper.The sandpaper showed no tearing or peeling after grinding for 30 min which meets the qualification requirements.