Waterborne latex coatings of color: II. Surfactant influences on color development and viscosity

A matrix of coating variables, nonassociative versus associative thickeners, different latex median particle sizes, individual surfactants and colorants [carbon black (CB), red, and yellow pigments], was examined for their influence on variances in coatings rheology and color development. Within the different coating groups, the variable of interest in this study was the surfactant added to the colorant formulation. In all three colorant formulations, sodium dodecyl sulfate (an anionic surfactant) provided poorer color development (CD) than in applied formulations containing an equivalent nonylphenol oxyethylene (EO) surfactant. In CB formulations, nonionic surfactants with higher EO content provide improved color development at low (2 mM) concentrations, but near equality in CD is achieved with low EO surfactants at higher concentrations. In contrast to CB formulations, red and yellow colorants exhibit good color development with high EO content nonionic surfactants only at low nonionic surfactants concentrations. This variance appears to be related to the interactions of surfactants with inorganic pigments (talc and laponite) in the colorant formulation. The coating’s rheology is related to latex, thickeners, and surfactant components of the paint, as has been noted in previous studies, but not to the nature of the color pigment. The viscosity of the hydroxyethyl cellulose (nonassociative type) and HEUR (associative type) thickened paint decreased with colorant addition due to dilution effects. There were no unusual deviations with the NP(EO)_x surfactants, except when a large hydrophobe nonionic surfactant [e.g., C₁₈H₃₇(EO)₁₀₀] is added. In HEC thickened coatings, the viscosity decreases when C₁₈H₃₇-(EO)₁₀₀ is in the colorant due to that surfactant inhibiting depletion flocculation. In the C₁₈H₃₇(EO)₁₀₀ coatings containing the HEUR thickener, significant increases in viscosity were observed, above the dilution values observed with the colorant addition. This is related to the viscosity maximum in the low concentration of HEUR with the C₁₈H₃₇(EO)₁₀₀ surfactant. Color development is independent of the viscosity profile of the coating. Presented in part at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 13–14, 2003 in Philadelphia, PA.     

Waterborne latex coatings of color: I. Component influences on viscosity decreases

For almost two decades, it has been known that the addition of colorants to a waterborne latex coating thicknened with an associative thickener will result in a viscosity loss. The influence of surfactants on viscosity variations in waterborne latex coatings, as discussed in our most recent JCTCoatingsTech article,¹ is the source of the viscosity decreases. To evaluate this problem, aqueous solutions containing large quantities of five different surfactants, and the smallest particle size of the colorants, carbon black (CB), were prepared. Large quantities of surfactant were used to allow for adsorption on, and stabilization of, CB. When traditional associative polymers (HMHEC, HASE, and a telechelic HEUR) were used to thicken carbon black dispersions, viscosity decreases were not observed, for most of the surfactnat is adsorbed on the CB’s surface. There is enough surfactant, however, to promote viscosity decreases in comb-HEUR thickened CB dispersions. Moving beyond the colorant dispersions, the CB, yellow, or red colorants were then added to a commercial latex paint that contains many surfactants, glycol ether, and coalescing aids, and significant viscosity decreases were observed. The decreases were very dramatic as the colorant concentration was increased to obtain deeper color tones, due to the additional excess surfactant added to the coating. Reduction in total surfactant levels in the colorant was an obvious solution, but this led to rub-up incompatibility. The conflict between viscosity retention and rub-up incompatibility was resolved when the surfactant concentration was reduced by adding to the colorant formulation compositionally different hydrophobically-modified poly(oxyethylenes) and hydrophobe-modified maleic acid co-oligomers. Presented in part at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 13–14, 2003 in Philadelphia, PA     

建筑涂料的技术发展及趋势

根据建筑涂料的特点, 介绍高耐候性涂料、弹性涂料等用树脂和树脂改性以及水性建筑涂料中合成树脂乳液的改进     

Fluorinated additives for stain-resistant matt latex paints

Latex paints are often preferred over solvent-based paints due to their good gloss and color retention, ease of handling, and lower volatile organic contents. However, matt latex paints tend to show poor stain resistance since they develop highly porous and rough surfaces. In recent years, matt latex paints have been improved in their stain resistance with resulting better cleanability, by adding hydrocarbon acrylic polymers and fluorine-containing compounds. In this work, we prepared fluorinated acrylic emulsions of the copolymer of butyl acrylate (BA) and perfluorobutylethylene (PFBE), which were introduced in latex paint compositions. The properties of the modified paints were evaluated by performing stain resistance tests with several domestic products. It was observed that they had good stain release properties, thus conferring good properties to the final painting system. They contain the self-cleaning behavior typical of fluorinated coatings, which have been proven by the decrease of their surface energies. Since the cleaning procedures of a matt paint film can also impart some gloss increase, the wet and dry burnishes were also evaluated. The results have shown improvements in stain resistance and cleanability of the modified matt latex paints with the maintenance of their stability and the coatings gloss as required.     

Interaction between styrene/butylacrylate latex and water soluble associative thickener for coalescent free wall paints

The effect of water soluble hydrophobically modified ethylene oxide urethane (HEUR) thickener on coalescent free wall paints was studied. Three systems were looked at: latex/thickener blends, model paints (containing no fillers that could have an effect on paint rheology) and satin paints (PVC 30%). The latexes used were a styrene/butylacrylate copolymer, designed for coalescent free wall paints. A full factorial statistical experimental design was employed to study the effect of latex and formulation variables on the viscosity response for the full range of shear rates encountered in paint application. The factors considered in the design were total latex surface area, polymerization surfactant level, thickener type and thickener concentration. The surfactant level was varied between 0.85 and 1.71 parts. The two HEUR thickeners were selected based on the manufacturer's claim that they exhibited good performance at different shear rates. The thickener levels were the extremes recommended by the manufacturer. Measurements were done on Haake, Rheometrics, Brookfield and ICI Cone & Plate rheometers. Total latex surface area and the thickener level are the two significant parameters for latex thickener blends and for model paints at the same significance level, this indicates good correlation between the two systems. The introduction of clay as a filler decreases the effect of all parameters studied.     

用于电脑调色的基础乳胶漆配方设计

分析了乳液体系、增稠体系对调色基础漆展色性的影响,并且探讨了调色基础乳胶漆中PVC与钛白含量的设计。     

Phase behaviors and film properties of dispersions and coatings containing associative and conventional thickeners

Phase-separation behaviors of latex dispersions, using commercial latices of three different median sizes, and pigmented coatings are examined. Both the dispersions and pigmented coatings at a 0.32 volume fraction of total dispersed phase were thickened with water-soluble polymers, with and without surfactant hydrophobes. Latex dispersions thickened with water-soluble polymers without hydrophobe modification follow the phase-separation behavior described by the volume restriction flocculation (VRF) concept (i.e., molecular weight of the thickener or particle size of the latex). This is surprising since commercial latices contain a variety of surface-stabilizing moieties, in addition to surfactant. Latex dispersions thickened with commercial and model hydrophobically modified ethoxylated urethane (HEUR) polymers do not follow the phase-separation behavior predicted by the VRF concept. The lack of correlation of phase behavior with latex median size in HEUR-thickened formulations led to an examination of four secondary thickeners, noted for providing high viscosities at low shear rates. With an all-acrylic, large median-size latex, the combinations of commercial HEURs with secondary thickeners are effective in eliminating phase separation; only partial reduction in phase separation is observed with a vinyl acetateacrylic large-particle latex. The influence of HEUR/secondary thickener blends on the film properties also is discussed. © 1993 John Wiley & Sons, Inc.     

Biodegradable multiblock PEO/PLA thermoplastic elastomers: molecular design and properties

Given the need for highly flexible biodegradable polymers, a series of poly(ethylene oxide)/poly(l-lactic acid) (PEO/PLA) (PELA) multiblock poly(ether-ester-urethane)s, were synthesized and characterized. The first step of the synthesis consisted of the ring-opening polymerization of l-lactide, initiated by the hydroxyl terminal groups of the PEO chain, followed by the chain extension of these PLA-PEO-PLA triblocks, using hexamethylene diisocyanate (HDI). The trimers comprised PEO segments in the 1000-10,000 molecular weight range, with the length of each PLA block covering the 200-10,000 interval. DSC and X-ray analyses revealed that, depending on their composition, amorphous matrices, monophasic crystalline materials and copolymers comprising two crystalline phases, were generated. The multiblock copolymers synthesized exhibited superior mechanical properties, with ultimate tensile strength values around 30 MPa, Young's moduli as low as 14 MPa and elongation at break values well above 1000%. Because of their phase segregated morphology, most of these multiblock copolymers displayed remarkable mechanical properties also when fully hydrated, with typical UTS values around 9 MPa.     

利用Pluronic嵌段共聚物的增溶胶束超滤分离技术

增溶胶束超滤 (MEUF)是新型膜分离技术 ,但迄今仅利用普通烷烃链表面活性剂作为其胶束物质 ,由于这些表面活性剂单体相对分子质量低 ,形成的胶束较小 ,不仅难以有效增溶有机分子 ,还可能透过超滤膜造成对水体的二次污染。聚氧乙烯 -聚氧丙烯 -聚氧乙烯三嵌段共聚物 (Pluronics)是一类重要的功能高分子 ,在合适条件下 ,它们在水溶液中聚集生成具有很大内核的胶束 ,这种胶束能有效增溶水溶液中的有机污染物。其次 ,Pluronic共聚物分子单体的大相对分子质量使其容易被超滤膜隔离 ,加上Pluronic共聚物无毒无刺激性 ,因而这类新型功能高分子适合用于增溶胶束超滤方法 ,实现对水体有机污染物的分离。综述Pluronic嵌段共聚物的胶束化、胶束结构、胶束增溶以及在增溶胶束超滤分离技术中的应用     

Use of polymers from biomass in paints

Furan and its derivatives can be synthesised from renewable vegetable resources using simple chemical reactions. The use of copolymers of furan as a replacement of petroleum-based polymers in latex paints could be beneficial if the price of petroleum rises substantially. We have therefore substituted these with furan-based polymers and studied the paint properties. The copolymers of furan and furfuryl acetate with maleic anhydride were incorporated into commercial latex paint systems as a replacement for petroleum-based polymers. Although the paints formed were slightly more yellow than desired, they showed increased hardness and resistance to water.     

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。     

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.     

Synthesis and properties of hydrophilic segmented block copolymers based on poly(ethylene oxide)‐ran‐poly(propylene oxide)

The present article discusses the synthesis and various properties of segmented block copolymers with random copolymer segments of poly(ethylene oxide) and poly(propylene oxide) (PEO‐r‐PPO) together with monodisperse amide segments. The PEO‐r‐PPO contained 25 wt % PPO units and the segment presented a molecular weight of 2500 g/mol. The synthesized copolymers were analyzed by differential scanning calorimetry, Fourier transform infra‐red spectroscopy, atomic force microscopy and dynamic mechanical thermal analysis. In addition, the hydrophilicity and the contact angles (CAs) were studied. The PEO‐r‐PPO segments displayed a single low glass transition temperature, as well as a low PEO crystallinity and melting temperature, which gave enhanced low‐temperature properties of the copolymer. The water absorption values remained high. In comparison to mixtures of PEO/PPO segments, the random dispersion of PPO units in the PEO segments was more effective in reducing the PEO crystallinity and melting temperature, without affecting the hydrophilicity. Increasing the polyether segment length with terephthalic groups from 2500 to 10,000 g/mol increased the hydrophilicity and the room temperature elasticity. Furthermore, the CAs were found to be low 22–39° and changed with the crosslink density. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117:1394–1404, 2010     

建筑涂料领域中影响电脑配色准确性的因素

电脑配色在涂料行业是一门新兴技术,颜色配方的准确性一直是配色师关注的问题。从色浆数据库的建立、基漆数据库的建立、颜色配方的设计、色浆与基漆的匹配、色浆/基漆批次稳定性等方面来阐述影响电脑配色精度的因素。     

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.     

Nonaqueous emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol. II. Adsorption of poly(ethylene oxide)–polystyrene–poly(ethylene oxide) triblock copolymer on latex particles

The adsorption behavior of various poly(ethylene oxide)–polystyrene–poly(ethylene oxide) (PEO‐PS‐PEO) triblock copolymer (TBC) s on acrylic latex particles in propylene glycol was studied. The composition of the PEO‐PS‐PEO triblock polymers varied from 41 to 106 in each PEO block length and from 18 to 41 in the PS block length. The location of the PEO‐PS‐PEO TBC was determined by analyzing for the physically adsorbed amount on the latex surface, the anchored mount on the surface, the entrapped amount inside the particle, and the “free” PEO‐PS‐PEO TBCs in the propylene glycol. A contour graph technique was applied to analyze the experimental data, which showed that a minimum existed for the physically adsorbed portion at a PS block length of about 30 units. When the PS block length was less than 30 units, the adsorption decreased with increasing PS block length, indicating rearrangement of mixed PEO brush and adsorbed PS block. When the PS block was greater than 30 units, the adsorption increased with increasing block length because of the poor solvency of the PS block in the propylene glycol medium, resulting in a collapse of the PS chain. Considering the binding energy between the PS block and the latex particle surface, which governs adsorption, it was hypothesized that a lower block length limit exists, below which no adsorption takes place. The solubility of the PS block in propylene glycol guides the important upper block length limit. The anchored fraction of the block copolymer increased continuously with increasing PS block length in the entire region investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1963–1975, 2001     

Comparison between the self‐assembling behaviors of PLLA‐PEO‐PLLA triblock copolymers and PLLA‐PEO‐PPO‐PEO‐PLLA pentablock copolymers

Poly(L ‐lactic acids) (PLLAs) were grafted to both ends of poly(ethylene oxide) (PEO) to produce biocompatible amphiphilic PLLA‐PEO‐PLLA triblock copolymers. The self‐assembling behaviors of two PLLA‐PEO‐PLLA copolymers in aqueous solutions were examined by Dynamic Light Scattering and Transmission Electron Microscopic techniques. PLLA‐PEO‐PLLA formed spherical micelles, whereas PLLA‐PEO‐PPO‐PEO‐PLLA pentablock copolymers were reported to produce vesicles. It is believed that the PPO segment within the PLLA‐PEO‐PPO‐PEO‐PLLA pentablock copolymers has a dominant role in the formation of vesicles. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

系统色浆的评价方法

从色浆的颜色体系、色浆技术、颜色接受性、对基础漆性能的影响、环保性能以及色浆本身的性能指标等方面说明色浆的评价评估方法,同时对开发系统色浆也有一定的指导意义,并为今后制定相应技术规范提供参考依据。     

Micellization, Interaction and Microenvironment in the Mixed Solution of Pluronics and Surfynol 104 with Nuclear Magnetic Resonance

The micellization, intermolecular interaction and microenvironment of molecular segments in the mixed aqueous solution of PEO-PPO-PEO triblock copolymer (Pluronic? F88, P84 and P123) and Surfynol? 104 (S104) were studied by nuclear magnetic resonance method. The results showed that the addition of S104 decreased the critical micellization temperature of copolymer. When its concentration was 0.5 g/L, the most reduction was up to more than 10℃ for F88, which was most hydrophilic in the selected copolymers. This reduction was caused by the hydrophobic interaction between S104 molecules and PPO segments. The addition of S104 enhanced the hydration of PEO segments most obviously for P123. And S104 slightly increased the hydration of PPO segments before the micellization, but obviously decreased their hydration after micellization, which was attributed to the hydrophobic interaction mentioned above and temperature rising. This effect was most observable for F88.