聚氨酯缔合型增稠剂的增稠机理和增稠效率研究

聚氨酯缔合型增稠剂作为一种典型的高分子缔合型增稠剂,在合成制备、增稠效率、增稠机理及刺激响应增稠等方面已经得到了深入的研究。本文综述了近年来国内外有关聚氨酯缔合增稠剂增稠机理和增稠效率影响因素的研究进展,并展望了水性聚氨酯缔合增稠剂的未来研究方向。     

有机高分子缔合型增稠剂的应用及增稠机理研究

介绍了有机高分子增稠剂的种类,疏水改性聚氨酯缔合型增稠剂的增稠机理及在乳液中的应用,综述了近年来国内外有关缔合型增稠剂的科研成果,展望了有机高分子缔合型增稠剂的未来研究方向。聚氨酯缔合增稠剂作为一种典型的高分子缔合型增稠剂,在合成制备、增稠效率、增稠机理及刺激响应增稠等方面已经得到了深入的研究,是未来有机高分子类增稠剂应用的研究方向。     

水性聚氨酯缔合型增稠剂的研究进展

介绍了水性涂料增稠剂的种类、水性聚氨酯缔合型增稠剂的增稠机理及影响因素;综述了近年来国内外有关缔合型增稠剂的科研成果;展望了水性聚氨酯缔合型增稠剂的未来研究方向。     

涂料用增稠剂市场概述

介绍了全球涂料用添加剂市场情况，着重介绍了涂料用增稠剂。对缔合型增稠剂、与水相相结合的非缔合型增稠剂、无机增稠剂、有机触变胶等类型的增稠剂分别加以阐述。     

增加乳胶漆着色时黏度稳定性的缔合增稠剂

本文介绍了一种新型的采用氨基树脂的缔合增稠剂。通过在分子中引入比聚氨酯型缔合增稠剂更多的憎水部分，从而达到使用缔合增稠剂后，即使再向水性涂料中加入溶剂如二元醇或表面活性剂时，黏度也能保持稳定。     

水性涂料用添加剂 第2讲 增稠剂

简述了增稠剂的种类、作用机理、特性和在水性涂料中的适应性。重点介绍了高分子型增稠剂和缔合型增稠剂的不同特性。     

水性纯丙木器涂料增稠剂的性能探讨

主要考查了碱溶胀增稠剂和聚氨酯缔合性增稠剂对水性木器涂料用纯丙乳液的增稠效率,并对比了不同增稠剂的喷涂施工性和流平性。试验结果显示,增稠剂的增稠效率与增稠剂类型并无直接的联系。但是碱溶胀增稠剂在喷涂施工性和流平性方面略显不足;聚氨酯缔合型增稠剂喷涂施工性好,流平佳,有利于制备高质量涂膜。     

缔合型聚氨酯增调剂在乳胶涂料中的应用

缔合型聚氨酯增稠剂的许多性能优于其他增稠剂。介绍了该类增稠剂的分子结构、增稠机理和添加方法。讨论了影响聚氨酯增稠剂增稠性的因素。     

新型的碱溶胀缔合型增稠剂

前言 鉴于缔合型增稠剂优越的流变性,已得到了广泛的认可,并已成为大部分建筑涂料所钟爱的产品。传统使用的二种主要的增稠剂是水溶性的纤维素,特别是羟乙基纤维素(HEC)及羟丙基甲基纤维素(HPMC)和碱溶胀或可溶型乳液(总称ASE)。如同其它分子量较高的非缔合型水性聚合物一样,这些增稠剂主要是通过流体力学机理,仅能提高水相的粘度(图1)。在有分散相胶体粒子存在的情况下,即颜料及乳胶粒子,增稠和流变将进一步受到另外的非缔合机理的影响。这可称为“体积限制”(Volume restri-ction)或“减液”(depletion)絮凝。     

乳液增稠技术的研究进展

增稠剂可以提高物系黏度,使物系保持均匀稳定的悬浮状态或乳浊状态,或形成凝胶。目前常用的增稠剂有纤维素及其衍生物类、聚丙烯酸及其共聚物类、非离子缔合型聚氨酯类等,对不同增稠剂特性的了解对于根据需要选择合适的增稠剂非常重要。主要以纤维素及其衍生物类、聚丙烯酸及其共聚物类、非离子缔合型聚氨酯类这三类主要的增稠剂为主,综述了乳液增稠的相关增稠机理以及研究应用技术。     

新型水性缔合型聚氨酯增稠剂的研制

利用二异氰酸酯和聚乙二醇在封端剂的存在下合成了一种水性聚氨酯缔合型增稠剂;考察了不同单体、封端剂以及反应工艺对产物增稠性能的影响;讨论了增稠剂的相对分子质量和相对分子质量分布与其增稠性能的关系。     

Control of rheology of water-borne paints using associative thickeners

Water-borne decorative topcoats generally show inferior leveling and open time compared to solvent-based paints. Basically, this behavior is caused by the divergent viscosity–solid content relationship for dispersions and emulsions and by the relatively high evaporation rate of water. Employment of associative thickeners may improve leveling and open time of latex paints only if they introduce a substantial amount of ‘network viscosity,' characterized by a short relaxation time and little dependence on solid content. This network viscosity enables one to formulate a paint with sufficient high-shear viscosity at a particle-packing density far below the value where low-shear viscosity starts to diverge. Addition of an associative thickener not only affects rheology, but also the interaction between latex particles: Associative HEUR thickeners may induce undesired phase separation by strong bridging between the latex particles. The influence of HEUR thickeners on latex particle interaction has been studied by turbidity measurements. The experimental results could qualitatively be interpreted very well by two-particle interaction potentials computed using the Self-Consistent-Field theory of Scheutjens and Fleer. It is demonstrated how viscosity, created by the addition of an associative thickener to a highly concentrated latex, can be split up into a polymer network viscosity and a contribution to (relative) dispersion viscosity. According to these analyses, reduction of the molecular weight of tri-block HEUR thickeners yields an increase of the favorable network viscosity and a reduction of the unfavorable dispersion viscosity. However, reduction of the molecular weight of the HEUR thickener is limited by the introduction of undesired phase separation (bridging flocculation) below a certain molecular weight.     

新型水性聚氨酯缔合型增稠剂的研制

通过二并氰酸酯和聚乙二醇在封端剂的存在下合成了一种水性聚氨酯缔合型增稠剂,考察了不同的单体、链封端剂以及反应的工艺条件对产物增稠性能的影响,并讨论了增稠剂相对分子质量和相对分子质量分布与其增稠性能之间的关系。     

聚氨酯缔合型增稠剂的研制

利用异佛尔酮二异氰酸酯（IPDI）与一定相对分子质量的聚乙二醇进行本体聚合得到聚氨酯单体，加入扩链剂和封端剂进行改性，最后与溶剂和助溶剂进行复配成缔合型聚氨酯增稠剂成品。对合成过程中的温度、催化剂、加料次序及滴加速率等条件进行了研究，同时对合成的缔合型聚氨酯增稠剂与国外某知名公司类似产品做了在乳胶漆中的应用对比研究。     

聚氨酯缔合型增稠剂(I系列)的研制与应用

利用异佛尔酮二异氰酸酯(IPDI)与一定相对分子质量的聚乙二醇进行本体聚合得到一定规格的聚氨酯单体,同时加入扩链剂和封端剂进行改性,最后与溶剂和助溶剂进行复配,制成缔合型聚氨酯增稠剂成品。对合成过程中的温度、催化剂、加料次序及滴加速率等条件进行了研究。     

Study of the rheology of aqueous radiation curable polyurethane dispersions modified with associative thickeners

The chemistry of radiation curable polyurethane dispersions is outlined with an emphasis on the microstructure of the aqueous polymer dispersion and the possible interactions with associative thickeners. The steady-shear flow was studied for two model dispersions prepared from the same unsaturated polyurethane but showing significantly different particle size distributions. A hydrophobically modified ethoxylated urethane (HEUR) associative thickener with a linear structure was incorporated at different amounts to the dispersions with varying particle volume fractions. The steady-state viscosity at 25 and 10 °C was always reached quickly after instant flow rate changes so that no significant thixotropic effects were reported within the experimental timescale. Without thickener, the flow curves of the two model dispersions exhibited a Newtonian behavior except at the highest volume fractions where shear thinning became apparent. The maximum packing values determined from the Krieger–Dougherty relationship were essentially the same for the two systems. In the presence of thickener, the flow curves were characterized by a Newtonian plateau followed by a marked shear thinning region even at low particle volume fractions. This behavior typically suggests the formation of a physical network between polyurethane particles and thickener molecules partly adsorbed onto the polymer surface. The zero-shear viscosity of the two dispersions was compared with respect to: (i) particle volume fraction and (ii) particle surface area at different HEUR concentrations. At a given volume fraction, the particle size affects the viscosity of thickened models. As a corollary, a relationship is found between the particles size and the level of thickener required to reach a target viscosity. This study offers practically relevant data in terms of application conditions and provides a better insight into the thickening protocol.     

聚氨酯缔合型增稠剂的合成及其应用性能研究

介绍了两款聚氨酯缔合型增稠剂(HEUR)的制备方法,包括一款假塑型增稠剂(增稠剂-万华A)和一款牛顿型增稠剂(增稠剂-万华B),并在乳胶漆配方中考察了这两种增稠剂的增稠性能、配方稳定性、色浆稳定性及展色性;并考察了自制增稠剂B的增稠效率及其在水性木器涂料中的应用。研究表明:合成的自制增稠剂A具有优异的增稠剂效率、良好的配方稳定性、色浆稳定性及展色性。自制增稠剂B具有高效的高剪切增稠效率,在水性木器涂料中性能表现优异,性能良好。     

Associative behavior of hydrophobically modified hydroxyethyl celluloses (HMHECs) in waterborne coatings

The associative behavior of hydrophobically modified hydroxyethyl cellulose (HMHEC) in polymer dispersions has been determined as a function of the composition of both the associative thickener (AT) and the latex. How changes in interaction between HMHEC and the latex influence the rheology of the latex thickener systems is discussed. Adsorption of HMHECs onto an acrylic emulsion strongly depends on the hydrophobe type and degree of substitution, as well as on the molecular weight of the associative thickener. The degree of latex adsorption is influenced dramatically by the stabilization system utilized, that is choice and level of surfactant and carboxylic acid content, in addition to the composition of the monomer mix. Rheological measurements demonstrate that HMHECs of specific composition can provide gloss emulsion paints with a balance of rheological properties, combining excellent levelling with sag resistance.