湿热处理对水曲柳木材水性漆涂膜性能的影响

Effects of wet-heat treatment on the performance of waterborne paint film of Fraxinus mandshurica

【目的】当水曲柳应用于家具、室内装饰及建筑等领域时,常通过表面涂饰来进行防护。但是使用环保的水性漆进行涂饰时,附着力有限。为了提高水性漆在水曲柳表面的附着力,本试验对水曲柳进行湿热预处理,并且研究了该预处理方法对水性漆的其他涂膜性能的影响。【方法】以水曲柳为基材进行湿热预处理,并对表面粗糙度、光泽度、色度进行测试。再用水性漆涂饰,待漆膜完全固化后,通过180°剥离测试,量化水性漆的附着力提升效果。还研究了湿热处理对漆膜耐冷热性能的影响,进一步采用红外光谱和电镜等方法探索该处理方法对提升水性漆在基材表面附着力的影响机制。【结果】湿热处理后得到的漆膜厚度为110.8μm。与未处理试样相比,该预处理方法可以有效提升基材的表面粗糙度,涂饰后漆膜的剥离强度提高了120.0%,厚度提升了14.6%。处理前和处理后试样的漆膜耐水性等级相同,说明湿热处理不会降低漆膜质量。进一步分析表明:1734和1604 cm^(-1)处的峰强度降低,说明湿热处理使基材的木质素发生降解;1728和1050 cm^(-1)处的振动峰强度降低,也是由于该处理使半纤维素降解。这些变化导致基材的表面粗糙度提升,孔隙率增加,从而提高了水性漆的附着力。【结论】湿热处理是提升水性漆在木质基材表面附着力的高效、环保的预处理方法,可在较好地保持漆膜的其他性能的前提下,提高水性漆对基材表面的防护能力。

[Objective]When Fraxinus mandshurica wood is used in the fields of furniture,interior decoration and architecture,it is often protected by surface coating.However,the adhesion of waterborne paint coating is limited.In order to improve the adhesion of waterborne paint coating on the surface of F.mandshurica,we conducted a wet-heat pretreatment on F.mandshurica and tested the effect of this pretreatment on other coating properties of waterborne paint coating.[Method]Using F.mandshurica wood as the substrate,it was subjected to a wet-heat pretreatment,and the surface roughness,glossiness,and chromaticity were tested.Then,it was painted with waterborne paint.After the paint film was fully cured,the adhesion improvement effect of waterborne paint was quantified through a 180°peeling test.The influence of wet-heat treatment on the thermal and cold resistance of paint film was also studied.In addition,infrared spectroscopy and electron microscope were used to explore the mechanism of the treatment in improving the adhesion of waterborne paint on the substrate surface.[Result]The thickness of the paint film was 110.8μm after the wet-heat treatment.Compared with the untreated sample,this pretreatment can effectively improve the surface roughness of the substrate,and the peel strength of the paint film after coating increased by 120.0%and the thickness increased by 14.6%.The water resistance grades of the untreated and treated samples were the same,which showed that the quality of the paint film was not reduced by wet-heat treatment.Further analysis showed that the peak strength at 1734 and 1604 cm^(-1) decreased,which indicated that the degradation of lignin was caused by wet-heat treatment,and that the peak strength at 1728 and 1050 cm^(-1) decreased,which indicated that the degradation of hemicellulose was also caused by wet-heat treatment.These changes led to the increase of surface roughness and porosity of the substrate,thus improving the adhesion of waterborne paint.[Conclusion]Wet-heat treatment is an efficient and environmentally friendly pretreatment to improve the adhesion of waterborne paint on the surface of wood substrate,which can improve the protective ability of waterborne paint on the surface of the substrate while maintaining other properties of the paint film.