探究颜基比对80%锌含量环氧涂料性能的影响

Study on the Effect of Pigment/Filler to Binder Ratio on the Performance of 80%Zinc Content Epoxy Coatings

在80%锌含量环氧涂料中,以长石粉作为另一种辅助颜填料,通过改变总颜填料与基料的比例(即颜基比),制备了临界状态附近4种不同颜基比(1.6、1.7、1.8以及2.0)的涂料样品,并探究了颜基比对涂膜形成结构以及涂膜防腐蚀性能的影响。测试结果显示,随着颜基比的增加,4种测试涂层的吸水率增大,96 h泡水测试后,颜基比为2.0的涂层吸水率约为1.6颜基比涂层的7.8倍;电化学测试Bode图中低频阻抗模量(Z_(0.01)Hz)减小,1.6颜基比涂层的阻抗值约为2.0颜基比涂层阻抗值的10倍,意味着涂层的阻隔性能减弱;连续冷凝、耐盐雾以及耐湿热防腐测试后涂膜的附着力均有所降低,表明了涂膜的防腐性能降低。尽管颜基比越高涂料的价格降低,但从环氧富锌底漆应具备良好的防锈性能再追求性价比的角度考虑,颜基比建议不高于2.0,以确保防腐测试后涂层仍具有优异的附着力(不低于5MPa)。

Based on 80%zinc content epoxy coatings and feldspar powder as another auxiliary pigment/filler,four coatings samples with different pigment/filler to binder ratios(1.6,1.7,1.8 and 2.0)near the critical state were prepared.The film forming structure and the anticorrosive property of these samples were investigated.The test results show that with the increase of pigment/filler to binder ratio,the water uptake of tested coatings gradually increases.After 96 h soaking in water,the water uptake of the 2.0 coatings is about 7.8 times that of the 1.6 coatings.The low frequency impedance modulus(Z_(0.01)Hz)in the Bode plot reduces,and the impedance value of the 1.6 coatings is about 10 times that of the 2.0 coatings,which means that the barrier property of the coatings is weakened.The adhesion of the coatings film decreases after condensation test,salt spray test and heat and humidity resistance test,indicating that the anticorrosive property of the film is reduced.Although the higher the pigment/filler to binder ratio,the lower the price of the coatings,from the perspective that the epoxy zinc-rich primer should have good anticorrosive property and pursue cost-effectiveness on this basis,the pigment/filler to binder ratio is recommended to be no higher than 2.0,to ensure that the coatings still show excellent adhesion(not less than 5 MPa)after the anticorrosive test.