Aspects of interactions in complex polymer coating formulations

Acid–base interaction parameters have been measured by inverse gas chromatography for mixed stationary phases of film‐forming polymers and pigments. The quantities of adsorbed polymer required fully to coat the pigment surfaces were established, and rheological measurements were used to evaluate the thickness of polymer barriers generated by the adsorption process. Both the barrier thickness and the critical amount of polymer needed to overcoat the pigments were found to be dependent on acid–base interactions. Acid–base considerations also determined the rate of material redistribution when a third component was added to premixtures of two‐component polymer/pigment combinations. Time‐dependent variations in the surface energies of polymer films were attributed to the component redistribution process. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1378–1386, 2000     

Lightly branched comb polyesters: Application in fast drying solvent-borne coating formulations

Novel oxazoline-based comb-polymers possessing linoleyl or oleic side chains have been synthesized and used to produce low viscosity coatings. Inclusion of the polymers in model paint formulations results in coatings that exhibit faster drying times than commercially available alkyd resin formulations. The comb polymers were produced from diol substituted oxazoline monomers that were synthesized through a scalable, solvent free protocol and purified by simple recrystallisation. Co-polymerisation of the oxazolines with adipic acid at 160 °C in the bulk resulted in the targeted polyester comb type polymers. The polymers were soluble in a range of organic solvents and compatible with commercial alkyd resins. Model paint formulations containing up to 40 wt% of the linoleyl-based comb polymers exhibited a dramatic reduction in viscosity (from 35 to 13 Poise at 25 °C) with increasing quantities of polymer added. Dynamic mechanical analysis (DMA) studies revealed that the drying rate of the model paint formulations containing the comb polymers was enhanced when compared with that of commercial alkyd resins.     

Application of gas-liquid chromatography to the study of gas-bitumen interactions

Gas-liquid chromatography (glc) has been used (Xu and Hepler, 1990) to obtain Henry's Law constants and infinite dilution activity coefficients for hydrocarbon and other vapour-phase solutes in two bitumens, Athabasca and Wolf Lake. Thermodynamic interaction between components widely different in molar mass can, however, be characterized by mass-fraction rather than mole-fraction based quantities and by the χ parameter, as has been the practice with polymer systems. The new parameters have been calculated and reveal more unfavorable interactions of the solutes with Wolf Lake than with the Athabasca material.     

Rheology of plastisol formulations for coating applications

A plastisol is a suspension of PVC particles and mineral fillers in a liquid phase composed of plasticizer and adjuvants. Plastisol formulations are commonly used in coating processes for flooring application. In the knife‐over‐roll process, they are subjected to a wide range of shear rates (0–10⁵ s^?1). They are adjusted in order to fulfil the target end‐use properties but their processability depends on their rheology. Plastisol based on three PVC resins with or without mineral filler have been investigated using a Couette device and a capillary rheometer. Results show a high impact of PVC particle content, particle sizes and distribution on rheology: a polydisperse formulation displays a shear‐thinning behavior in the whole shear rates range and exhibits yield stress; a monodisperse formulation shows a shear thinning behavior at low shear rate, followed by a Newtonian plateau, then a more or less pronounced dilatancy peak depending on plasticizer rate and finally another shear‐thinning behavior; a bidisperse resin stands in between. Filler content also impacts the rheology: shear thickening effects at intermediate shear rates decrease or even disappear; however, the viscosity increase is important for low shear rates and depends on the filler particle size and particle size distribution. POLYM. ENG. SCI., 57:982–988, 2017. © 2016 Society of Plastics Engineers     

Application of headspace analysis to the study of aroma compounds-lipids interactions

Taking into account interactions between aroma compounds and food components is necessary to better manage the flavoring of food products. These interactions occur at a molecular level and reflect changes, at a macroscopic level, in thermodynamic equilibria, such as solubility or volatility. The rate of transfer of an aroma compound from the liquid to the vapor phase can be affected as well. The behavior of aroma compounds in water and lipid solutions was studied in two complementary ways, a thermodynamic and a kinetic approach (head-space analysis). The transfer rate of volatiles at the liquid-water interface does not only depend on the hydrophobicity of the aroma compounds. Vapor-liquid partition and activity coefficients show the presence of solute-solvent interactions. The Gibbs free energy values indicate their physicochemical nature.     

无磷涂装前处理技术在汽车涂装中的应用

介绍了一种节能、环保、低温的无磷涂装前处理新技术.将该技术应用于汽车电泳涂装前处理,所得漆膜的附着力、抗冲击强度和耐腐蚀性能均可满足汽车工业要求,槽液更换周期可由原来的3～4个月延长至8～10个月,操作温度由原来的40～45℃降低到20～30℃.该工艺可共线处理铁板、镀锌板和铝板等多种基材.但是,无磷转化工艺的应用还需要有更高泳透力的电泳漆与之配套,以克服车身漆膜出现的针孔问题.     

A laboratory tool to study the plodding characteristics of soap formulations

A simplified laboratory size scale technique has been outlined for use in the study of plodding characteristics and changes therein due to formulative variations. The quantity of product needed for evaluation being in the range of 50 to 100 g.     

常温固化氟碳涂料在桥梁领域的应用

综述了FEVE氟碳涂料在桥梁领域的相关标准和应用情况。介绍了日本钢桥防腐涂装标准及其涂装体系、国内TB/T1527附录D和JT/T695-2007附录C规定的氟碳涂料性能指标。论述了国内外桥梁防腐涂装氟碳面漆体系。对我国氟碳涂料和丙烯酸聚氨酯涂层在主要典型大气环境下的暴露腐蚀老化结果进行了比较。分析了FEVE氟碳涂料的耐候性和耐粘污性。     

纳米技术在涂料中的应用

综述了纳米技术在涂料中的应用研究情况,指出了纳米涂料技术的关键问题和应注意的问题,并提出了发展前景。     

氯化橡胶涂料在重防腐涂装中的应用

氯化橡胶涂料属于重防腐涂料。在C4严重腐蚀大气环境条件下,氯化橡胶配套涂层有5~15 a的使用寿命,性价比高。介绍了氯化橡胶涂料的优缺点,在生产及应用中存在的问题以及改性方法。建议采用水相法、非四氯化碳溶剂法生产氯化橡胶树脂,发展高固含量氯化橡胶涂料,并扩大氯化橡胶涂料在船舶制造、非标集装箱、水利电力、化工和航标制造等行业的应用。     

包覆型铝粉颜料在水性涂料中的应用

以正硅酸乙酯(TEOS)和乙烯基三乙氧基硅烷(VTES)为前驱物,通过溶胶-凝胶反应在铝颜料表面形成了一层致密的包覆层,再通过甲基丙烯酸甲酯(MMA)和丙烯酸(AA)的自由基聚合反应对铝颜料进行第二层包覆,制备了含亲水基团的包覆型铝粉颜料,以此包覆的铝颜料配制了水性铝粉涂料.研究了铝粉及交联剂的用量、涂料黏度和烘烤温度...     

凹凸棒石粘土在双组分聚氨酯涂料中的应用

考察凹凸棒石粘土(简称凹土)替代立德粉作为聚氨酯涂料填料的可行性,进行了遮盖力、光泽度、硬度、附着力、冲击强度等指标测试。结果表明,凹土经简单热处理即可用于聚氨酯涂料,替代部分立德粉;凹土1#填充性能与滑石粉相当,优于凹土2#和碳酸钙、高岭土、云母石、硫酸钡的填充性能。在获得同等涂料性能条件下,凹土1#对立德粉的最大替代量为50%,凹土2#添加量可达35%。     

水溶性底胶在PVDC涂敷薄膜生产中的应用

介绍了水溶性底胶的定义、性能,采用水溶性底胶生产PVDC涂敷薄膜时烘干和冷却步骤的注意事项,国内外水溶性底胶性能现状;比较了采用水溶性底胶或溶剂性底胶生产的PVDC涂敷薄膜的性能;展望了水溶性底胶在PVDC涂敷薄膜生产中的应用前景。     

可膨胀石墨在水性饰面防火涂料中的应用

以可膨胀石墨(EG)为物理膨胀体系,制备了膨胀型水性饰面防火涂料,采用小室法、锥形量热仪(CONE)、扫描电镜(SEM)等手段分析了可膨胀石墨及其与阻燃协效剂复配对饰面膨胀型防火涂料性能的影响。研究发现,EG的加入改善了膨胀炭质层的结构,大大提高了涂料的防火性能。选用3.5g、80目的EG,所得涂料的防火性能最佳,耐火时间达33min。可膨胀石墨与阻燃协效剂复配能够进一步降低涂料燃烧的烟气释放。当EG与二氧化锡按质量比为1∶1复配,所得涂层的生烟速率峰值与仅含EG的涂层相比下降78.4%,抑烟性能最好。     

薄膜前处理技术在汽车涂装中的应用

以冷轧钢板和热轧钢板为基材,分别采用不同厂家的薄膜前处理工艺配套阴极电泳涂装,研究了不同工艺条件下涂层的物理机械性能和耐蚀性能,并与传统磷化工艺进行对比,分析了薄膜前处理技术在车厢、车架涂装线应用的可行性。结果表明,对于车厢、车架用冷轧钢板,薄膜前处理工艺配套阴极电泳涂装所得涂膜的物理机械性能与传统磷化工艺相当,虽耐蚀性略低,但仍能满足车厢线的技术要求;对于车厢、车架用热轧钢板,选择不去除氧化皮的工艺,采用薄膜前处理技术也能够满足车厢、车架线阴极电泳配套的技术要求。     

节能型运行模式在汽车涂装生产中的应用

介绍了北京现代汽车有限公司轿车二厂涂装车间在节能降耗方面的改善措施,如面漆线隔天/隔班单线生产,生产间歇期间部分设备停歇,设备启动时间按季节进行标准化.在充分利用涂装车间生产能力的前提下,根据不同时期能源消耗的情况,采用不同的生产运行模式,从而合理组织资源,有效降低了生产运行成本.     

轻质石油罐导静电涂料的应用

分析了石油产品贮罐导静电涂料防腐性能失效的原因,讨论了导电填料的电极电位、涂层抗渗透性及干膜厚度对罐壁防锈寿命的影响.根据不同油品的使用要求和贮罐的结构类型,设计了油罐内壁导静电防腐涂层配套方案:无机富锌底漆,以炭黑、石墨为导电填料的防静电中间漆,以金属氧化物为导电填料的聚氨酯或环氧防静电面漆.     

Application of one-dimensional mechanical formulations to model the sagging behavior of a polymer sheet

The deformation of a heated plastic sheet clamped on two opposite sides subject to sagging under its own weight was examined experimentally and then modeled using two separate one-dimensional approaches based upon cable (membrane) and beam formulations. The cable formulation neglects both bending and shear deformation, but includes a generalized Maxwell viscoelastic constitutive model to capture the time-dependent nature of sheet sag. The resulting equations are integrated using a Runge-Kutta technique and solved via a shooting method. The beam formulation is based upon the Timoshenko theory and thus includes shear deformation along with the flexural contributions. A finite element method is developed from application of the principle of virtual work for the beam written in curvilinear coordinates in order to include the effects of finite deformation. A generalized Maxwell model is again employed to account for the time-dependent material response. In both formulations, the method of reduced variables is used to describe the variation of material response with temperature. The effect of temperature and thermal relaxation is included. The particular case of a styrenic material is discussed in detail.