【作者】 王翊；

【导师】 叶世超；

【作者基本信息】 四川大学 ， 化学工艺， 2004， 硕士

【摘要】 涂层干燥是一个涉及化学工程、化工热力学、高分子化学和物理等学科的复杂过程。常用的对流干燥法,热效率低,干燥时间长,漆层表面受热不均匀,干燥品质不理想。红外辐射具有节能、容易控制等优点,不存在由于穿透深度不够而影响内层加热效果的问题,特别适合于油漆一类薄层物料的干燥,因而具有良好的应用前景。基于涂料成分的差异,进一步研究不同涂层的干燥特性、优化干燥条件对干燥过程十分必要,但目前对红外烤漆的实验、理论和生产应用方面的研究还不够深入,因此涂膜的红外干燥研究有着重要的意义。本文采用醇酸清漆和酯胶调和漆作为实验物料,采用红外加热的方式烘烤漆膜,通过电子天平测量不同操作情况下涂层的质量变化,测定涂层表面温度曲线,并分析了各主要因素对干燥过程的影响。研究表明,固定干燥距离时,提高辐射源温度可缩短干燥时间;在固定辐射温度的条件下,减小干燥距离对漆膜的干燥有利;较高的干燥温度和较小的干燥距离可以提高干燥速率,但应考虑涂料和底基的耐热性,避免过高的温升速率使其变质;红外烤漆具有匹配吸收的特点,涂层在匹配温度下的干燥更为有利。实验得出了红外烤漆的最佳操作条件:黑色酯胶调和漆:辐射源温度232℃,漆层与加热板间距离11.4cm;无色醇酸清漆:辐射源温度151℃,漆层与加热板间距离11.4cm。按照漆膜内溶剂的扩散机理,建立了红外烤漆的数学模型,并进行了数值计算,模型计算结果与实验数据基本符合一致,从而验证了本文所提出的数学模型的正确性。更多还原

【Abstract】 Drying coated film is a complicated process that refers to the chemical engineering, chemical thermodynamics, macromolecule chemistry and physics. The choice of drying method is not unique as the different coated films. Because of low drying efficiency of the traditional hot air convection, the process needs much time, the layer surface has asymmetric superficial temperature, it affects the product quantity. So the choice of the drying manner and research of the drying process is very important. The infrared technique has much advantage such as the energy saving, well heat effective, easy control etc. For some thin material as paint layers, the infrared ray can radiate to the being heated material as electromagnetic wave modality, penetrate in the film and finish the mass and heat transfer, so the influence to the effect layer induced by not enough penetrating depth will not appear, and the application will highly spread.This works selected alkyd varnish, which involves in the oxidation thermohardening polymerization paint and black ester-gum ready-mixed paint, which involves in the crude resinousness thermoplastic paint as experimental material. But the two kinds of materials both need long drying time (the alkyd varnish: seemingness drying out 6hours, drying completely 12 hours; the black ester-gum ready-mixed paint: seemingness drying out 6hours, drying completely 24 hours). Intended for searching for the drying behavior, we ground plan to use infrared technique to drying the two films. We use a electronics weighing scale to measure the changes of the quantity of a coated film on a metal plank in the drying process at different operation condition <WP=4>and analyzed each factor to the influence of the infrared drying process. Then we survey the superficial temperature of coat and analysis all the main factors to the influence of the process. So we gained the best condition for the two paints and build a drying model for the whole process, which could provide the experimental base for the infrared application in industry. The experimental result indicate: with the certain distance between the paint layer and the heat plank, the drying process will be influenced by the radiant temperature, the higher radiant temperature is, the quicker drying process and higher superficial temperature are; with the certain radiant temperature, the dry process will be influenced by the distance, the nearer distance is, the quicker drying process and higher superficial temperature are; The high temperature and low distance radiates are beneficial to the paint layer drying. Because the infrared drying process of paint is a match absorption process, it is best to dry material at the match temperature range. But we should consider the species of the coating and the coat support in case they will be destructed by high temperature. The best experimental condition for infrared drying paint is: for the black ester-gum ready-mixed paint is 232℃ of radiant temperature and 11.4cm distance between paint layer and heat plank ; for the alkyd varnish is 151℃ of the radiant temperature and 11.4cm distance between paint layer and heat plank.更多还原