Rheology of high solid coatings. I. Analysis of sagging and slumping

The rheology of sagging and slumping of high solid coatings on vertical surfaces is analyzed in terms of a non-Newtonian power-law model. The results indicate that, in order to have good sag control and good sprayability at the same time, high solid coatings should be pseudoplastics with a power constant of about 0.6 and a viscosity at 1 sec^-1 of about 25 poise at the temperature of interest. This theoretical prediction is confirmed experimentally.     

助剂对厚浆型环氧涂料流变性能的影响

环氧树脂涂料由于具有突出的附着力，良好的耐蚀性，品种和性能的多样性等优点，在涂料工业中得到了广泛应用。然而，由于厚浆型环氧涂料内颜填料含量高、粘度大、流平性差等弊病，严重影响了其装饰作用，降低了保护作用。通过助剂的添加，可以很大程度地改变这些缺陷。本选择了流变助剂中的有机膨润土、BYK-410、MT和流平剂中的BYK-354，并通过改变其用量，检测其对环氧涂料性能的影响，尤其是对涂料流挂性能、流平性能和粘度的影响。     

新型PMMA防护涂料技术及应用进展

介绍了PMMA防护涂料的组成、固化机理、性能(与聚脲对比)、施工方式和应用领域。PMMA防护涂料是一种基于甲基丙烯酸甲酯(MMA)树脂的新型高性能防水材料,它能快速固化形成一层坚韧无缝的涂膜。PMMA防护涂料高固体分、使用安全,能以涂料体系(清漆或者色漆)、自流平体系、石英砂地坪体系或者碎石地坪体系应用于混凝土底材、石质底材、木质底材、瓷砖底材、钢结构底材等,其无缝涂膜耐化学品性能优良、耐紫外光老化性能优良,防滑耐磨,维护方便。     

可厚涂高固体分涂料的研究及其应用

研究了可厚涂高固体分涂料的固化和流挂的控制途径,及其在汽车涂装中的应用,以达到保护环境、节能的目的。提出了该涂料的固化可通过优化催化剂用量和固化条件来控制,流挂可通过添加流动控制剂来控制,并列举了它们的试验结果。     

淋涂玻璃烤漆的研制

讨论了颜基比、基体树脂/交联剂配比、流平剂种类和添加比例、催化剂种类和添加比例,对涂料的流平性能、涂料在油墨上的重涂性能、涂膜附着力、漆墨层间附着力、涂料遮盖力、干燥速度、储存稳定性以及涂膜耐水性、耐溶剂性及硬度的影响。结果表明:选择有机硅类流平剂添加比例为0.04%0.05%,颜基比为0.8:1,氨基树脂/基体树脂配比为0.3:1,选择长碳链二酸类有机酸催化剂加入比例为0.8%1.0%,在淋涂工艺中于150℃条件下烘烤15min制备成的单组分溶剂性玻璃烤漆涂膜具有优良的遮盖力、耐水性、耐溶剂性、附着力、漆墨层间附着力及高硬度。同时涂料还具有适宜的重涂性能、优良的储存稳定性及较好的流平装饰效果。     

紫外光固化封底涂料的研制

研制了一种用于表面粗糙的水泥板、木板等建筑材料的快速封底处理的紫外光固化涂料,该涂料组成为:预聚物55份(质量份,下同)、稀释单体40份、光引发剂3份、助剂2份、填料35份。所得涂料流平性好,不需要添加流平剂,可形成均匀的涂层;其成膜固化速度快,固化膜具有较强的附着力,且耐酸性、耐碱性、耐盐性好;同时该涂料有较好的防沉降性、贮存稳定性和施工性。     

谷朊粉在水性建筑涂料中的应用

研究了将谷朊粉溶解于水的方法和其在水性建筑涂料中的应用：谷朊粉的耐水性差，不能用作建筑涂料的主要基料，但其具有良好的粘结性、流动性和流平性，可用在合成树脂乳液内墙涂料中，作增稠剂使用，使涂料具有良好的流平性和涂膜外观，而成本与常用的增稠剂相差不大。     

The role of sag control agents in optimizing the sag/leveling balance and a new powerful tool to study this

In order to obtain glossy coatings with a high quality appearance it is necessary that surface irregularities created during paint application or during drying/curing of the paint level-out sufficiently while sagging problems are avoided. We have recently developed the so-called falling wave method that can be used to determine the sag and leveling behavior of wet paints during drying and curing in a quantitative manner. This method is very useful in identifying the cause and nature of poor coating appearance and facilitates development of paints with good sag and leveling behavior.     

超级抗划伤自干涂料设计技巧

介绍了一种可用于任何基料上的超级抗划伤固化涂料的制备方法,即先用30%～50%的溶剂可分解硝化纤维素及20%～30%的改性高聚物,加入适量的纳米材料流平剂、消泡剂,600 r/min搅拌均匀;然后在1500 r/min高速搅拌下慢慢加入含羧基的硬树脂,使其细度≤15μm,最后加入余下的低聚物单体。本产品特点是一种超级抗刮伤,环保、与任何基材上的底漆附着良好,柔韧性与基材匹配的单组分超级抗划伤自干涂料。     

Interaction of rheology, geometry, and process in coating flow

A final coating of uniform thickness implies good leveling and the avoidance of defects during film formation. Though generally desired, this objective is often unmet. The outcome of a coating process depends on the nonlinear interaction of the rheology, process variables, and substrate geometry. Understanding the role of rheology is complicated by difficulties in linking fundamental rheological properties with coating performance. During a coating process, forces of varying type, magnitude and duration act on the fluid film. For non-Newtonian coatings the viscosity varies with both time and position within the coating layer, making predictions of flow behavior quite difficult. One answer is computer simulation, using numerical techniques to solve a set of nonlinear differential equations governing the flow. The rheological and other physical properties are parameter values for the program. We present results of mathematical modeling and numerical simulation of a coating imperfection known as a “dripmark.” The model includes non-Newtonian rheology, substrate shape, surface tension, and gravity. We compare theoretical prediction with experimental observation in a study of two architectural paints. We also describe a new method of quantitatively measuring the surface profile of a coating defect. Presented at the 79th Annual Meeting of the Federation of Societies for Coatings Technology, on Nov. 3–5, 2001, in Atlanta, GA. Strongsville Research Center, 16651 Sprague Rd., Strongsville, OH 44136. Dept. of Mechanical Engineering, University of Delaware, Newark, DE 19716.     

巴士客车用丙烯酸聚氨酯罩光清漆的制备

介绍了以聚酯树脂和特种助剂对罩光清漆进行改性,制得了适合巴士客车使用的丙烯酸聚氨酯罩光清漆。分析了聚酯树脂和特种助剂对罩光清漆的丰满度、抗划伤性能、流平性和施工性能的影响。结果表明当选用高固含、高羟基聚酯树脂对丙烯酸树脂进行改性时,涂料具有较好的丰满度和抗划伤性能;当流平剂选用丙烯酸类和有机硅类搭配使用时,可大大提高罩光清漆的流平性能;当触变剂BYK-410的用量为0.3%时,清漆一次涂装干膜60μm不流挂,当DBE慢干剂用量为2%时,涂料具有好的施工性能。     

高流平、耐沾污性内墙乳胶漆的研制

以聚乙烯醇为增稠流平剂及使用一种高分子蜡乳液制成的乳胶漆 ,改善了涂料的流平性和涂膜的憎水性。分析了蜡乳液用量对涂膜耐沾污性的影响和聚乙烯醇用量对涂料流平性的影响     

新型双组分聚氨酯改性固化交联剂的合成

合成了一种改性TDI-TMP加成预聚物并研究了其在聚氨酯木器涂料中的具体应用;实验表明,该加成预聚物具有良好的贮藏稳定性,配漆后混合液低粘高固、刷涂性好,漆膜丰满度佳和耐冲击性优及较好的耐候性,并且,性价比高,完全可以替代普通的TDI-TMP加成物。     

Surface tension studies of additives in acrylic resin-based powder coatings using the Wilhelmy balance technique

A modified Wilhelmy balance technique using thin fibers as solid probes has been applied to study the effect of silicone additives in acrylic resin-based powder coatings on the surface tension of non-reactive binder systems. By measuring the temperature dependence of the surface tension in the temperature range between 140 and 180°C, it could be shown that the silicone additives investigated had a very different surface activity in the molten acrylic resin. Due to the high accuracy of the measuring technique and the good reproducibility of the experiments the influence of different additive concentrations on the surface tension was detectable even at very low concentrations (below 1 wt.%).

Compared to the pure powder coating binder which has a surface tension of about 30 mN/m the values decreased between 2–15 mN/m depending on the type of the silicone additive. In addition, the temperature coefficient −(dγ/dT) of the surface tension of the binder melt was changed. In the case of two additives, the surface tension of the powder coating and its temperature coefficient were lowered considerably. This effect of additives is desirable to reach good wetting and leveling of the powder coating.     

无溶剂环氧自流平地坪涂料技术探讨

无溶剂环氧自流平地坪涂料以其优异的施工性、流平性、柔韧性、耐冲击性、耐化学介质腐蚀等特点,广泛用于各行各业的工业厂房.本文研究了组成该地坪涂料的环氧树脂、活性稀释剂、固化剂、颜填料及助剂的各种性能特点和对涂层性能的影响,探讨了无溶剂环氧自流平地坪涂料系统的施工工艺,对工程应用具有一定的指导意义.     

Application of nitrile butadiene rubber for flexible,chemically protective coating

Rheological properties of toluene solutions of nitrile butadiene rubber, of different molecular weights (M_w, 290,000,320,000, and 450,000) and acrylonitrile contents (30 and 40 percent), were investigated at low (0.1 S^?1) to medium (20,0 S^?1) shear rates, in order to determine their feasibility for dip-coating applications. The effect of a surface-active additive, bentonite, and the solid content (15 and 20 wt percent) on solution viscosity was of main interest. At low zero-shear viscosity (<50 Pa·S) an excessive sagging of the wet film was experienced; at high zeroshear viscosity (>100 Pa-·S) the coating showed poor leveling. Zeroshear viscosity was found to be less affected by bentonite than oligomer-based solutions, at the same time, the solid content and the molecular weight of the polymer had more pronounced effects. With a proper balance of the parameters, seamless coating films were achieved, with excellent tensile and tear properties, and good permeation resistance against benzene.     

Inorganic/organic hybrid coatings for aircraft aluminum alloy substrates

A series of water-based stable sol–gel systems have been developed. Various functional groups including amino, epoxy, vinyl, and allyl groups can be incorporated into the sol–gel network to interact with organic polymer resins. The solid content of these sol–gel-based coating formulations varies from 2.5 to 45%. The sol–gel coating of alumina–silica networks derived from low solid content solutions (2.5%) has been developed and evaluated to replace the current conversion coating pretreatment process. Sol–gel coatings derived from the high solid content solutions (17–45%) have shown excellent mechanic strength, good adhesion, and provide corrosion protection of the aluminum substrate when cured at elevated temperatures. Sol–gel/epoxy resin hybrid coatings have been formulated and studied. The hybrid coating showed enhanced mechanical strength such as hardness and abrasion resistance. When cured at elevated temperatures (80°C), all of the hybrid coatings studied passed wet adhesion testing. Some of the hybrid coatings pass wet adhesion testing when cured at room temperature. However, water-sensitivity remains for most of the room temperature cured hybrid coatings.     

环境友好型无溶剂环氧自流平地坪涂料的制备

介绍了无溶剂环氧自流平地坪涂料的制备,并对树脂、活性稀释剂、颜填料、助剂及固化剂的选择进行了讨论。检测结果表明,该涂料的性能优越,尤其是流平性好、施工工艺简单,涂膜的光泽高、丰满度好,特别适用于地下停车场、医药、食品、电子、精密仪器等行业。     

Tribological behavior studies of chemically bonded phosphate ceramic coatings reinforced with modified multi-walled carbon nanotubes (MWCNTs)

To improve the wear resistance of the chemically bonded phosphate ceramic coatings, MWCNTs are selected as the reinforcement after the modification. The high temperature wear experiment is carried out to investigate the wear behavior of the coatings with different temperatures. The results suggest that, when the temperature is below 500℃, MWCNTs can decrease friction coefficient, and the lowest friction coefficient is about 0.28, but MWCNTs lose the lubricant function at 500℃ and the friction coefficient keeps at the level of ~ 0.68. In addition, the wear resistance of coatings is improved with the introduction of MWCNTs at 100℃ and 300℃ (the wear rate is below 15X10^-3mm³/Nm), but keeps similar level at 500℃ (the wear rate is ~ 22 × 10⁻³mm³/Nm). Besides, the wear mechanism of the coatings reinforced by MWCNTs is also investigated based on the wear behavior and microstructural characterizations. MWCNTs improve the fracture toughness by preventing the crack generation and forming the bridge when crack occurs, which leads to smooth wear tracks and good wear resistance of coatings. The coatings with MWCNTs achieve poor wear resistance at 500℃ because MWCNTs lose their strength and resistance to fatigue by oxidizing.     

反应性丙烯酸酯制备常温无溶剂涂料

文章利用丙烯酸酯树脂预聚物与交联单体在引发剂和促进剂的作用下进行自由基聚合反应交联成膜,制备了一种低粘度,高固含量,表干时间短,低污染,硬度高,柔韧性好,附着力强,耐候性好的涂料。文中着重探讨了丙烯酸酯树脂预聚物的合成,并对涂膜性能进行了测试;找到了控制预聚物粘度的方法及涂料的适宜配方;可为丙烯酸类路标涂料的生产应用提供一定的借鉴。