成膜助剂在乳胶漆中作用分析

乳胶漆是绿色环保涂料,但它成膜性较差。为了提高其成膜性能,必须加入成膜助剂。成膜助剂在乳胶漆中起着重要作用,它能降低乳胶漆的成膜温度,改善乳胶漆的成膜性能。本论文对乳胶漆的成膜机理、成膜剂的选择以及成膜剂的作用及其影响因素作了分析。     

颜料对乳胶漆耐洗刷性能的影响

乳胶漆的耐洗擦性能反映乳胶漆的综合性能。本试验系统研究了颜料体积浓度、填料用量、乳液聚合物、成膜助剂对乳胶漆耐洗擦性能的影响。试验发现增加颜料和填料用量，降低乳胶漆的耐洗擦性能，使用玻璃化温度低，弹性大，极性低的乳液聚合物，乳胶漆耐洗擦性能提高越明显；同时还发现使用成膜助剂可以显著改善乳胶漆的耐洗擦性能。     

乳液的最低成膜温度及其影响因素

乳胶漆的成膜行为可以通过最低成膜温度（MFT）进行表征。介绍了MFT的测定方法。详细讨论了玻璃化温度、乳液粒径、成膜助剂、干燥条件及贮存时间等因素对MFT的影响。     

乳液涂料成膜过程中成膜助剂的挥发

成膜助剂的水溶性、相对挥发速度影响其在涂膜干燥过程中的挥发。热失质量和激光粒度分析发现，成膜助剂挥发过程分两个阶段。在第一阶段，成膜助剂一方面挥发，另一方面因浓度提高而向聚合物粒子内部渗透，油溶性成膜助剂挥发速度比较快；在第二阶段，成膜助剂的挥发受到成膜助剂分子由聚合物内部向外扩散的控制，油溶性成膜助剂挥发速度比较慢。由于成膜助剂水溶性的这种差异，导致油溶性成膜助剂容易出现缩边现象。这对于成膜助剂的选用和减量增效，以及提高成膜性能具有重要意义。     

浅谈内墙厚涂开裂的解决方法

针对内墙乳胶漆在厚涂开裂上的缺陷,通过在无石棉纤维腻子板上调整乳胶漆成膜助剂、涂膜厚度和兑水比例,观察乳胶漆的厚涂开裂情况并进行对比,得出厚涂开裂与成膜助剂、涂膜的厚度、刷涂质量以及刷痕有关,其都会影响涂膜在低温下的成膜速率,并浅谈了厚涂开裂的解决方法。     

改性胶体及其对高PVC内墙乳胶漆性能的影响

介绍了改性胶体改善乳胶漆性能的原理，讨论了使用改性胶体配制的高PVC乳胶漆的性能和改性胶体对乳胶漆性能的影响。改性胶体能够降低乳胶漆中分散剂、增稠剂和冻融稳定剂的用量，改善乳胶漆的流平性和涂膜的手感，提高抗分水性能，但对于涂膜的耐洗刷性没有明显的影响。     

影响内墙乳胶漆耐擦洗性能的因素

对内墙乳胶漆的配方进行了研究,讨论了不同乳液、颜填料、成膜助剂和分散剂等市售产品对内墙乳胶漆耐擦洗性能的影响。结果表明,硅丙乳液的耐擦洗性能最好,纯丙和苯丙乳液次之,醋丙乳液较差。金红石型钛白粉比锐钛型钛白粉的耐擦洗性能好,但其成本较高。重质碳酸钙的粒径越小,涂膜的耐擦洗次数越少。体质颜料的用量过少,会影响漆膜的遮盖力和机械性能;用量过多,则漆膜易粉化,从而影响耐擦洗性能。成膜助剂可以显著改善漆膜的耐擦洗性能,市售成膜助剂醇酯12和巴斯夫7034分散剂的耐擦洗性能较好。     

丙二醇对乳胶涂料性能的影响

研究了聚醋酸乙烯酯水性乳胶涂料中助溶剂丙二醇的加入量对涂料性能的影响,在其他助剂、颜填料和主要成膜物质加入量都不变的情况下,分析了丙二醇不同加入量对涂料粘度、表面干燥时间、对比率、耐洗刷性的影响规律,从而确定最佳的加入量。研究结果表明:随着丙二醇质量的增加,体系粘度会下降,表面干燥时间会缩短,涂膜的对比率呈现不规律变化,涂膜的耐洗刷性次数会下降。     

水性涂料的成膜助剂

汇集了水性木器涂料常用的一些成膜助剂以及与成膜有关的性能数据,讨论了成膜助剂与最低成膜温度、成膜效率、涂膜硬度和VOC的关系。同时讨论了从成膜助剂着眼制备“零”VOC水性木器涂料的重要性和可能性。     

冷拼法制备水性丙烯酸改性醇酸涂料

通过颜料、填料、助剂搭配使用,冷拼法制备水性丙烯酸改性醇酸涂料,测试涂膜物理和化学性能,并讨论了成膜助剂和防闪锈剂对涂膜的影响,发现丙二醇可以提高涂膜耐盐雾性能,醇酯十二可以提高涂膜光泽。     

Latex film formation: atomic force microscopy and theoretical results

We have critically examined the kinetics of latex film formation using an atomic force microscope to obtain corrugation height data as a function of time, temperature, molecular weight, particle size, etc. The results show that the film forming process obeys viscoelastic time/ temperature superposition principles, thus indicating a direct relationship between the kinetics of film formation and rheological properties. Film formation kinetics are examined under ‘wet’ and ‘dry’ conditions, with film formation occurring almost ten-times faster under wet conditions than dry. This proves for the latex system examined that capillary pressure from the water meniscus is the dominant driving stress for film formation. Past theories for latex film formation are reviewed, and problems and deficiencies are noted. A new theory for film formation from a dry latex system is presented, which is based on the use of the Boltzmann Superposition Principle to relate the changing stress and strain fields as the latex particles deform. The predictions of theory and the experimental data show excellent agreement over nearly four decades of time.     

Preparation of glycol esters of soybean oil fatty acids and their potential as coalescent aids in paint formulations

Soy oil glycol monoesters have been prepared through the transesterification of soybean oil with ethylene, diethylene, propylene, and dipropylene glycols. The molar ratio of soybean oil to glycol used in these reactions was 1∶6. The catalyst used in these reactions was lithium carbonate, 0.5%, based on soybean oil. The transesterifications were carried out at 180–190°C. The composition of soy oil glycol esters and their physical properties were determined. The soy oil glycol esters were incorporated in a water-based paint formulation as the coalescent aid, and the minimum film formation temperature was determined. The minimum film formation temperature results indicated that these esters can be used as coalescent aids in latex paint formulations to help in continuous film formation at or below room temperature.     

An ESEM investigation of latex film formation in cement pore solution

Environmental scanning electron microscopy (ESEM) and complementary methods were employed to study the time dependent film formation of a latex dispersion in water and cement pore solution. First, a model carboxylated styrene/n-butyl acrylate latex dispersion possessing a minimum film forming temperature (MFFT) of 18 °C was synthesized in aqueous media via emulsion polymerization. Its film forming property was at a temperature of 40 °C, studied under an ESEM. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. Film formation is significantly retarded when the latex dispersion is present in cement pore solution. This effect can be ascribed to adsorption of Ca²⁺ ions onto the surface of the anionic latex particles and to interfacial secondary phases. This layer of adsorbed Ca²⁺ ions hinders interdiffusion of the macromolecules and subsequent film formation of the latex polymer.     

水性环氧丙烯酸酯乳液涂层成膜性能

采用细乳液聚合法制备了环氧丙烯酸酯复合乳液,考察了固化温度、固化时间及磷酸酯乳化剂含量对环氧丙烯酸酯复合涂膜性能的影响,结果表明环氧丙烯酸酯复合乳胶粒子呈均匀的球形结构,且平均粒径分布在150 nm左右。当固化温度为120℃、固化时间为2 h、磷酸酯乳化剂含量为3%时,涂层的耐腐蚀性较好。研究了复合乳液的成膜过程和防腐蚀机理,通过复合乳液与金属底材形成致密的钝化膜,阻隔水分子和无机离子的浸入,提高了涂层的防腐性能。     

Film formation of monodispersed polystyrene latex at high temperature

This report discusses the drying behavior of monodispersed polystyrene latex at elevating temperature with particular attention to the relationship between water evaporation rate and morphological evolution during the film formation process. At the first stage, water evaporation rate was less influenced by the skin film formed at the latex/air interface, which was consistent with Croll's model. During this stage, a drying front advanced from the top film toward the bulk dispersion. At the final stage of film formation, the water evaporation rate was less than that of the initial stage, and another drying front developed from the interior region outside the system. Two distinct boundaries corresponding to the opposite directions of the second drying front between completely dried region and wet region were found if the film was peeled off the container surface. Besides, some particular morphologies were found in the completely dried region, which was likely related to preferable coalescence among the particles induced by capillary force because of water evaporation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1835–1840, 2001     

聚丙烯酸酯/铜酞菁蓝复合乳胶膜中颜料颗粒的分散状态

引言功能颗粒存在下,水性胶乳在织物、纸张、皮革等目标基质表面的焙烘成膜是众多生产领域中普遍存在着的一个固化成型过程。通常认为功能颗粒在乳胶膜内初级粒子形式的均匀稳定分散可赋予涂层最佳的功能性和黏结牢度[1]。但目前常见的、基     

On the role of colloidal crystal-like domains in the film forming process of a carboxylated styrene-butadiene latex copolymer

Environmental scanning electron microscopy (ESEM) was employed to study the mechanism of film formation of a carboxylated styrene-butadiene latex copolymer with a glass transition temperature (T_g) of 6 °C. ESEM allows the investigation of wet samples in their native state which is required to study the drying process of latex dispersions. The film forming process was tracked by time-dependent ESEM monitoring of the latex particle morphology and by observing the different stages occurring during the drying process. The focus of our study was an analysis of the three-dimensional (3D) arrangement of the latex particles and a comparison of their appearance on the surface and in the center of the coalesced film. It was found that in the course of film formation, the latex particles arrange in domains which are similar to colloidal crystals. Such domains occur at the stage of dense particle packing. Particle coalescence appears to begin first in these domains before a continuous and homogeneous film is formed which then spreads across the entire substrate. The results suggest that for our carboxylated styrene-butadiene copolymer the current model known for the film forming mechanism which includes four main steps should be complemented by two additional ones, namely the arrangement of particles in crystal-like domains and the beginning of coalescence within these domains. This specific behavior only occurs for monodisperse latices.     

DRYING OF LATEX FILMS OF POLY(VINYL ACETATE)

Drying of Poly(vinyl acetate) latex films has wide application in the industries of synthetic fibers, adhesives, coatings, paints, etc. In this investigation, drying of Poly(vinyl acetate) latex film was studied experimentally in a drying tunnel where the air velocity and temperature were controlled. The water evaporation rate was obtained by weighing the latex film during the drying process. The weight loss of latex was measured for different polymer concentrations, film thicknesses, drying areas, temperatures, and air velocities. Results emphasize the important role of these parameters on the relative water transport from the latex film. Increasing air velocity and temperature leads to a significant increase of the weight loss of latex and drying rate. Changing other parameters affects only the rate of weight loss but not the constant drying rate.     

DRYING OF LATEX FILMS OF POLY(VINYL ACETATE)

ABSTRACT

Drying of Poly(vinyl acetate) latex films has wide application in the industries of synthetic fibers, adhesives, coatings, paints, etc. In this investigation, drying of Poly(vinyl acetate) latex film was studied experimentally in a drying tunnel where the air velocity and temperature were controlled. The water evaporation rate was obtained by weighing the latex film during the drying process. The weight loss of latex was measured for different polymer concentrations, film thicknesses, drying areas, temperatures, and air velocities. Results emphasize the important role of these parameters on the relative water transport from the latex film. Increasing air velocity and temperature leads to a significant increase of the weight loss of latex and drying rate. Changing other parameters affects only the rate of weight loss but not the constant drying rate.