低温涂敷型环氧粉末涂层玻璃化转变温度异常问题研究  

Reserch on Glass Transition Temperature Abnormity of Low Application Temperature Fusion Bonded Epoxy Coating

作　　者：赵岑[1] 赵利[1] 相政乐[1] 刘进东[1] 刘恒恒 陈春林[1] 

机构地区：[1]中海油能源发展股份有限公司管道工程分公司,天津300452

出　　处：《涂料工业》2017年第10期29-33,44,共6页Paint & Coatings Industry

摘　　要：为解决高钢级钢管对三层结构聚乙烯(3LPE)防腐工艺提出的新要求,粉末涂料企业针对性地开发了一系列涂敷温度低于190℃的低温涂敷型环氧粉末(LAT-FBE)。若干型号的LATFBE涂层存在固化转化率大于99%,但玻璃化转变温度差值(ΔT_g)却明显小于-2℃的现象,即"ΔT_g负向超差"问题。评价涂层固化度的2个指标发生冲突,严重影响LAT-FBE涂层合格与否的准确判定。在理论分析的基础上,对ΔT_g负向超差问题进行了实验研究。结果表明:导致ΔT_g负向超差的直接原因是涂层T_(g3)异常升高,其根本原因是LAT-FBE涂层的分子结构处于不稳定状态,分子链段柔性较低,涂层存在较大的内应力。In recent years, a series of low application temperature fusion bonded epoxy （LAT-FBE） powder which can be applied below 190 ℃ has been developed in order to solve the new challenges of 3-layer PE（3LPE） anticorrosion for high grade steel pipe. Although the conversion degree of some LAT-FBE coatings can meet the requirements of 99%, the difference in the glass transition temperature between two successive thermal analysis scans （△T） is significantly over -2℃ , which can be defined as ＂△Tg negative over value＂. The two indicators evaluating the curing degree of LAT-FBE coating are contrary, and it seriously influences the quality evaluation of LAT-FBE coating. Experimental research based on theoretically analysis for ATg negative over value is made in this paper. The results show that the direct cause of △Tg negative over value is abnormally increase of Tg3. The root cause is the unstable state of LAT-FBE molecular structure, and the molecular chains lack flexibility, the coating shows great internal stress.

关 键 词：环氧粉末 低温涂敷 玻璃化转变温度 △Tg负向超差 

分 类 号：TQ637.82[化学工程—精细化工]