不同加速试验对环氧/聚氨酯涂层失效机制的影响

研究了模拟南海海洋大气环境下铝合金表面环氧锌黄/丙烯酸聚氨酯涂层体系的失效过程,通过循环加速、紫外/冷凝和中性盐雾的对比试验,探讨了在循环加速试验中紫外-冷凝试验和盐雾试验分别对复合涂层失效过程以及对聚氨酯面漆和环氧底漆失效机制的影响。结果表明,紫外-冷凝过程对丙烯酸聚氨酯面漆有较强的破坏作用,但对复合涂层体系整体的阻抗变化影响较小;紫外-冷凝过程中,位于面漆玻璃化转变温度范围内的试验温度,以及紫外光对氨基甲酸酯基团的破坏作用,是导致面漆发生破坏的主要原因。盐雾试验对面漆的失光率和色差变化影响不大,但连续的盐雾渗透对涂层体系的阻抗下降具有明显的加速作用,同时导致涂层与基材的附着力显著降低。相比单独的紫外-冷凝试验或盐雾试验,循环加速试验综合考虑了南海海洋大气中强太阳辐射、高温高湿、高盐分和温差等环境因素,能更准确反映南海大气环境中复合涂层的失效过程。     

环氧/聚氨酯涂层在4种环境中失效行为的EIS

用电化学交流阻抗法(EIS)研究了环氧富锌底漆/环氧云铁中间漆/丙烯酸聚氨酯面漆这一涂层体系在3.5%NaCl溶液、3.5%NaCl溶液+紫外辐射、湿热和盐雾这4种环境中的失效行为,探讨了特征频率下的相位角和涂层电阻值之间对应的关系。结果表明:中频区10Hz处涂层相位角随时间的变化曲线和涂层电阻值随时间的变化曲线有良好的相似性,据此可以对所研究的涂层体系失效程度进行快速评价;所试验的4种腐蚀环境对所研究的涂层体系的破坏作用由小到大依次为:3.5%NaCl溶液盐雾湿热3.5%NaCl溶液+紫外辐射。     

适用于酸雨地区的防腐涂层配套体系性能研究

为选出适用于酸雨地区的涂层体系,通过交流阻抗谱、人工耐老化试验、耐酸雾试验等评价了环氧底漆/丙烯酸改性聚酯面漆、环氧底漆/氟硅丙烯酸面漆、环氧底漆/聚氨酯面漆、环氧底漆/聚硅氧烷面漆和环氧底漆/氟硅面漆这5种涂料配套体系的耐蚀性、耐人工老化性和耐酸雾性,并用扫描电镜观察了涂层在模拟酸雨溶液中浸泡120 d后的表面形貌。结果表明,环氧底漆/硅氧烷面漆体系具有良好的耐人工气候老化和耐酸雾性,孔隙率小,附着力好,可为酸雨地区的输变电铁塔提供较好的防护。     

不同腐蚀试验的电化学阻抗谱评价

采用电化学阻抗谱分析了环氧涂层的介质浸泡、ASTM-B117盐雾试验、PROHESION循环试验的性能变化。实验结果表明:介质浸泡更侧重考察涂层的屏蔽作用,对环氧-聚酰胺体系酸性电解质更容易导致涂层失效;而盐雾试验更容易导致涂层吸收水分,干湿交替增加了有机涂层吸水能力;划痕试验表明样板在ASTM-B117和PRO-HESION遵循不同的腐蚀机理。     

太阳能反射镜镜背保护涂料的应用研究

以灰色环氧磷酸锌防腐涂料为底漆、丙烯酸改性聚硅氧烷涂料或丙烯酸聚氨酯涂料为面漆,作为太阳能反射镜镜背保护涂料,对保护涂料的施工工艺以及2种面漆的防护性能等进行了研究,研究表明:丙烯酸改性聚硅氧烷涂料配套体系的附着力、反射率、中性盐雾、CASS喷雾试验、人工加速老化、湿热试验及抗气候循环试验等各项性能指标达到了相应的技术标准,较传统的丙烯酸聚氨酯面漆在恶劣环境中更适合太阳能反射镜的保护。     

采用紫外老化?中性盐雾腐蚀循环试验评价有机涂层的性能

通过傅里叶红外变换光谱以及光泽、色差、附着力等测试手段,对冷轧钢板表面环氧底涂以及环氧底漆+聚氨酯面漆涂层体系经过紫外老化(UV)、中性盐雾试验(NSS)或紫外老化-中性盐雾腐蚀循环试验(UV–NSS)后的性能进行了对比研究。相比传统的单一NSS和UV试验,UV–NSS试验提供了一个动态多因素相互作用的试验体系,更接近复杂的服役环境,反映出涂层实际的耐腐蚀效果。     

电化学方法研究环氧防锈涂料实验室实验与实海环境实验的相关性

用电化学交流阻抗法(EIS)研究了环氧防锈涂料在实海浸泡实验和3.5%NaCl溶液浸泡实验、盐雾实验、湿热实验3种实验室加速实验中的失效行为,探讨了实海浸泡实验和3种实验室加速实验的|Z|_(0.01 Hz)对应关系。结果表明:4种腐蚀环境对所研究的涂层体系的破坏作用由小到大依次为:3.5%NaCl溶液实海浸泡湿热盐雾;相对实海浸泡实验,盐雾实验对环氧涂层腐蚀失效的加速因子约为2.3。     

交流阻抗技术在S97耐盐雾防腐蚀涂料配方设计中的应用

在S97耐盐雾防腐蚀涂料的配方设计阶段，采用电化学交流阻抗技术确定了环氧云铁防锈底漆和丙烯酸聚氨酯面漆的颜料体积浓度，并对S97耐盐雾防腐蚀涂料的防腐蚀性能进行了研究。     

水性重防腐涂料在桥梁钢结构上的应用研究

制备了水性环氧富锌底漆、水性环氧云铁中间漆、水性丙烯酸聚氨酯面漆作为配套涂装体系应用在钢箱梁上。实验结果表明,该配套体系具有很好的耐盐雾及施工性能,完全能够替代油性环氧富锌底漆、环氧云铁中间漆、丙烯酸聚氨酯面漆配套体系,并且环保,符合国家节能减排相关政策。     

纳米二氧化硅改性环氧涂料在建筑护栏中的防护应用

纳米二氧化硅改性环氧树脂涂料因在树脂分子链中引入了Si─O柔性链段和富有弹性的网状硅氧四面体结构,使得涂层的柔韧性和附着力得到显著改善,防腐蚀性能提高。以纳米二氧化硅改性环氧涂料为底漆、丙烯酸聚氨酯涂料为面漆,应用于海南某高级酒店护栏的防护中,详细介绍了涂层体系的施工工艺,包括底材前处理、喷涂纳米二氧化硅改性环氧底漆、刮涂腻子层、喷涂丙烯酸聚氨酯面漆以及修补,测试了复合涂层的性能。结果表明,该复合涂层附着力1级,冲击强度≥50 kg·cm,柔韧性≤1 mm,硬度≥2H,耐盐雾腐蚀时间≥3 000 h,耐人工加速老化时间≥1 000 h。该涂层配套体系在酒店护栏上使用一年后,涂层无失光、变色等现象,显示出优异的防护性能和装饰性能。     

Performance of paint systems with polyurethane topcoats, proposed for atmospheres with very high corrosivity category

The EN ISO Standard 12944-5 describes the types of paint and paint systems commonly used for corrosion protection of steel structures. In this work four paint systems, applied on steel, including polyurethane topcoats, recommended for atmospheres with high corrosivity (C5 category), codified by 1–4, were studied. Systems 1 and 4 include zinc rich primers and epoxy/polyamide intermediates, system 2 has solvent free epoxy/polyamide primer and intermediate and, system 3 is a hybrid system with vinyl–acrylic water based primer and a high solids epoxy/polyamide intermediate. Systems 2–4 have acrylic–polyurethane topcoats and, the topcoat of the system 1 was identified as an aliphatic polyurethane.

According to EN ISO 12944-6, water condensation and neutral salt spray tests were performed. Three exposure times were considered taking into account the durability ranges of paint systems: low, medium and high, respectively. The paint systems were complementary submitted, during 30 days, to ultraviolet radiation with water condensation test according to ASTM G 154. At the same time, natural exposure was conducted in the marine atmosphere of Sines, with very high corrosivity (>C5).

The paint adhesion, before and after artificial ageing, was evaluated by cross-cut test and, for the systems with dry thickness greater than 250 μm, by pull-off test. Visual inspections were carried out.

For the exposure in UV radiation test chamber and at test site, gloss reduction, colour change and chalking were measured. Chemical changes on polyurethane topcoats exposed in the UV radiation test chamber were studied by Fourier transform infrared spectroscopy (FTIR).

In spite of the higher aesthetic degradation by UV radiation, of the aliphatic polyurethane topcoat of the system 1 relatively to the acrylic–polyurethane topcoats of the other systems, system 1 with ethyl silicate zinc rich primer and epoxy intermediate, was the one that presented the best corrosion protection when exposed in artificial and natural salty environments. At the test site, the worst anticorrosive behaviour seems to be presented by the system 2 with two coats of solvent free epoxy paint.     

装备维修用带锈底漆的筛选

通过温度试验、盐雾试验、交变湿热试验和耐腐蚀试验考察了4种带锈底漆分别与S04-60面漆组成的涂层体系在简单处理后的铁锈板和铝锈板上的性能。试验结果表明,H53-32环氧带锈防锈底漆和S04-60丙烯酸聚氨酯面漆配套性良好,其涂层体系在两种基材上的初始附着力均为2级,高温贮存、低温贮存、温度冲击、盐雾试验后外观及附着力均无明显变化,交变湿热试验后外观完好,铁板附着力3级,铝板附着力2级,耐腐蚀试验时间均超过720 h,综合性能最佳,可以用作装备维修时的铁基材和铝基材的防护底漆。     

输电铁塔有机防护涂层的人工老化行为

为了预测输电铁塔有机涂层的使用寿命,达到对其长期保护的目的,研究了不同周期人工加速老化试验中复合涂层(环氧底漆+环氧云铁中间漆+丙烯酸聚氨酯面漆)样本的外观形貌、附着力、红外光谱和孔隙率的变化,建立了附着力?老化时间、孔隙率?老化时间、官能团指数?老化时间等数学模型。结果表明:氙灯加速老化时间12~15 d为涂层老化的重要节点,其间涂层粉化和开裂程度从轻微变中等;附着力随时间推移而先增大后减小;在12~36 d,孔隙率随老化时间延长呈指数式增长;红外光谱官能团指数在12 d内的变化速率明显增大,老化时间与羰基指数(OI)、氨基指数(NI)、环氧基指数(CI)的数量关系均可用同一类型的方程拟合,相关性较好。在实验初期,漆膜的NI随老化时间的延长而急剧增大,而OI的增加较为缓慢,表明丙烯酸聚氨酯面漆中的氨基官能团对老化更为敏感,老化更快。当丙烯酸聚氨酯面漆的NI增大到接近漆膜失效时的值时,环氧中间漆的CI开始增大,表明中间漆开始老化。     

Non-substrate EIS monitoring of organic coatings with embedded electrodes

Electrochemical impedance spectroscopy provides a quantitative evaluation of the protection afforded by coatings on metals. Two constraints are that the coating is under immersion and that the substrate acts as the working electrode with the counter and reference electrodes located in the electrolyte. The use of embedded electrodes placed between a topcoat and primer can relax these constraints and make EIS monitoring more applicable to coatings in the field. A two-electrode, non-substrate configuration involves two embedded electrodes on a coated panel acting as the working and counter/reference electrodes. This configuration has been used to characterize the interlayer between a topcoat and primer under the assumption that the current passed through the interlayer. Simulated results have been presented where current passage for a non-substrate configuration was through the metal substrate. The results associated with a urethane topcoat/epoxy primer system and an alkyd topcoat/alkyd primer system are presented to demonstrate the feasibility of monitoring the substrate where the substrate is not an electrode. The degradations of the coatings were induced using the ac–dc–ac accelerated test where the immersed coatings were subjected to cycles that involved a dc cathodic potential condition that promoted the cathodic reactions at the metal/coating interface.     

高性能水性工业防腐涂料配套体系的研究与应用

以自制高性能水性丙烯酸聚氨酯树脂(PUA)乳液为主要基料,制备了高性能水性防腐面漆,并研究了以水性环氧富锌底漆、水性环氧云铁中间漆为配套的水性工业防腐配套体系,并进行常规性能、耐化学介质、耐盐雾、耐人工老化等性能的检测分析。结果表明,以高性能水性工业防腐配套体系的防腐涂料可替代传统的溶剂型防腐涂料在相关领域的应用。     

The failure behavior of a polyurethane composite coating in 3.5% NaCl solution under ultraviolet irradiation

The failure process of inorganic zinc‐rich/micaceous iron oxide epoxy/aliphatic polyurethane composite coating in 3.5% NaCl solution under ultraviolet irradiation (UV) was studied with electrochemical impedance spectroscopy (EIS) and Fourier transform infrared (FTIR) spectroscopy. UV irradiation significantly accelerated failure process of the composite coating in NaCl solution. The effect of UV on failure process of the coating system in 3.5% NaCl solution may be divided into two stages: in the early stage, the thermal effect generated by the ultraviolet irradiation is the main reason leading to the increase in coating porosity, but this effect is not serious and the coating remains high impedance and good protection ability. In the latter stage, the fracture of polymer chains in the top coating by UV irradiation is the main factor resulting in quick decrease of coating performance. C N and C O bonds in polyurethane coating are broken by UV irradiation, leading to quick increase of the coating porosity and decrease of the coating resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Studies on corrosion resistant properties of inhibitive primed IPN coating systems in comparison with epoxy-PU systems

Though blending polymers to obtain high performance materials is an old practice, the new trend in such an approach is the emergence of interpenetrating polymer networks (IPNs) as binders for protective coatings with improved properties. In this study, one ambient curing IPN-type polymer alloy developed out of epoxy and acrylic polyurethane systems as a high performing binder was formulated into paints and evaluated in comparison with the currently used conventional epoxy polyamide and polyurethane systems. A three-coat system consisting of a zinc phosphate primer, a micaceous iron oxide (MIO) undercoat, and a topcoat was formulated out of the IPN along with a similar system of epoxy primer, epoxy undercoat, and a PU topcoat. A two-coat system of the same primer with an IPN clear topcoat and a similar system with epoxy has also been studied. All the systems were studied under accelerated laboratory tests and field tests at a corrosive location. The results are reported and conclusions are drawn in this article. An erratum to this article can be found at     

环氧富锌/氯化橡胶涂层体系腐蚀过程的电化学阻抗谱

采用环氧富锌作为底漆、氯化橡胶作为面漆，研究了涂层体系腐蚀过程中电化学阻抗谱(EIS)的变化。结果表明，腐蚀初期环氧富锌/氯化橡胶涂层体系中底漆的厚度比例与涂层的防护性能无关，而在腐蚀中后期，随底漆厚度比例适当增大，涂层自修复能力增强，离子等腐蚀介质在涂层中的传输速度得到显著延缓，涂层吸水率和孔隙率明显降低，涂层防护性能出现短时间升高。当环氧富锌底漆为涂层总厚度的2/3左右时，涂层体系的防护性能最好，而仅有底漆或面漆的体系则不具备良好的防护性能。