柔软型自交联涂料印花粘合剂的研制

合成了柔软型自交联聚丙烯酸酯类涂料印花粘合剂，井对单体的配虑、乳化剂的配虑及用量、引发剂用量、反应温度和时间进行了研究，确定了最佳合成工艺。     

DSC evaluation of binder content in latex paints

The estimate by differential scanning calorimetry of the enthalpy of thermal decomposition of the organic fraction in a complex material can be used, in proper conditions, for evaluating the concentration of the organic components. The application of this technique of thermal analysis to latex paints aimed at identification of binder content is discussed in this paper. On the one hand it gives good results on binder content estimate; on the other hand it highlights some aspects of the thermal decomposition of polymers enclosed in an inorganic matrix. The phenomena of thermal decomposition are studied for the main components of latex paints, i.e. for polymers, and for complete paint formulations. The materials considered include widely used binders for the manufacture of latex paints such as vinyl acetate/Versatate copolymers and styrene/acrylic copolymers, rheology modifiers such as cellulose ethers and other standard components of latex paints. Formulations representing typical latex paints with different binder content and simplified polymer/filler systems are considered. Although decomposition paths are very different for different polymers and for the same polymer in different concentrations, the overall heat output is consistent and proportional to the amount of polymer in the sample. Therefore identification by DSC measurements of the binder content in a latex paint appears as a feasible technique.     

Effect of precipitated calcium carbonate additions on waterborne paints at different pigment volume concentrations

Titanium dioxide (TiO₂) due to its high refractive index, is widely used in paint industry as a white pigment. In order to reduce this high cost of TiO₂, a part of TiO₂ is generally substituted by some other industrial mineral fillers such as calcite and calcined kaolin; however, this substitution affects the quality of paints in terms of stability, coverage (opacity), brightness (gloss), scrub resistance (film toughness), etc. In the present paper, precipitated calcium carbonate (PCC) was substituted for TiO₂ in paint mixture at three different pigment volume concentrations (PVC). It was observed that substitution of TiO₂ by PCC depends on PVC value at which there is an optimum PCC amount. The quality of paints produced by PCC along with its rheological properties was evaluated based on standard features in both wet and dry paints such as viscosity, density, opacity and gloss values. Addition of PCC increases the opacity to a certain point. Similarly, scrub resistance and viscosity increases with the addition of PCC at all PVCs, however, viscosity is not as much critical for the paint production. On the other hand, there is no any systematic effect of PCC on gloss value of the paint. This study overall demonstrates that PCC can be successfully used to substitute TiO₂ only with a careful adjustment of PVC and other extenders used in the paint formulation.     

The effect of amorphous chalcogenides on mechanical and anticorrosive properties of protective organic coatings containing high amounts of zinc metal particles

The objective of this paper concerns reduction of zinc metal content in organic coatings while preserving their high anticorrosive efficiency. The two goals can be achieved by using amorphous chalcogenides as components of the protective coating. Special attention was paid to materials containing Ge₂₀Se₈₀, Ge₃₀Se₇₀ and Ge₄₀Se₆₀, which were characterized by physico-chemical properties. An epoxy ester resin was used as binder for the investigated organic coatings. Organic coatings were prepared by combining zinc metal with amorphous chalcogenides. The resistance of the prepared films was evaluated using the results of mechanical tests. The anticorrosive efficiency of the prepared films was evaluated using the results of direct corrosion tests. Thus the following conclusion can be made from the results of anti-corrosive tests: the higher the pigment volume concentration of amorphous chalcogenides in the coatings, the higher the protective performance of the paint against corrosion.     

The role of auxiliary monomers and emulsifiers on wet scrub resistance of various latex paints at different pigment volume concentrations

This work is an attempt to study the effect of different latex types containing various auxiliary monomers and emulsifiers on their pigmentation and their corresponding behavior on scrub resistance. The auxiliary monomers investigated were acrylic acid (AA), methacrylic acid (MAA), and itaconic acid and the emulsifiers contained sodium lauryl sulfate (SLS) and sodium dodecylbenzene sulfonate (SDBS). It was shown that a semibatch polymerization technique which led to smaller particles and sharper size distributions is preferable. The best wet scrub results were obtained by using MAA and SLS. It was also shown that the proper selection of an auxiliary monomer generally depended on the range of incorporated pigment volume concentration (PVC). At high PVCs, AA gave better performances compared with MMA. The reverse effect was shown to occur at low PVCs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

工业漆体积固含量的计算方法探讨

根据工业漆的体积固舍量,可以计算涂料在不同干膜厚度下的理论涂刷面积(单位m~2/L),从而推算工程的涂料理论用量(单位kg/m~2).通过定义、推导等研究了工业漆体积固含量的计算方法,该方法对配方设计、涂料施工应用等具有指导作用.     

Titania pigment particles dispersion in water-based paint films

The distribution of titanian pigment, in dry water-based paint films in the presence of polymeric dispeersants containing different functional groups was investigated. The polymeric dispersants chosen were polyacrylic acid and polyacrylamide momo-and copolymers modified with hydroxyl and/or carboxylate groups. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to assess the distribution of the titania pigment particles in the surface and bulk, respectively, of the paint films, which was then compared to the gloss and surface roughnes of these films. In the absence of dispersant, the pigment distribution in the paint film was not uniform and relatively large pigment aggregates appeared at the surface, resulting in a rough surface and low gloss value. All dispersants both decreased surface roughness and increased the gloss of the dry paint film, with the dispersant type considerably enhancing the pigment dispersion in the dry paint film, in agreement with results obtained in aqueous pigment suspensions. In the presence of polyacrylamide homopolymer, the paint gloss increased slightly and further increased with the hydroxyl-modified polyacrylamide copolymer. The paint gloss was highest in the presence of polyacrylic acid or carboxylate/hydroxyl-modified polyacrylamide.     

Electrochemical study of protective behavior of organic coating pigmented with zinc aluminum polyphosphate as a modified zinc phosphate at different pigment volume concentrations

Electrochemical impedance spectroscopy was employed to evaluate protective performance of the solvent-borne epoxy coatings pigmented with zinc aluminum polyphosphate as a representative of phosphate-based anticorrosion compounds at different Lambda values. Furthermore, the effective ratio of the pigment volume concentration (PVC) to the critical pigment volume concentration (CPVC) was determined. To compare the function of zinc aluminum polyphosphate and zinc phosphate incorporated into coatings, electrochemical noise method as well as electrochemical impedance spectroscopy was taken into consideration. The trend and magnitude of charge transfer, coating and noise resistances plus the amplitude of the current noise fluctuation indicated superiority of the modified pigment. In order to provide an insight into the mechanism by which anticorrosion pigments improve protective behavior of coating, performance of bare metals exposed to pigment extracts was assessed through taking advantage of electrochemical impedance spectroscopy and electrochemical noise method as well.     

Influence of organic pigment particles on millbase flow of nitro-cellulose/alcohol-rich liquid inks

Millbase flow of nitro-cellulose/alcohol-based inks deteriorates above a critical pigment weight fraction in the ink which differs from pigment to pigment. Below this critical concentration the inks are flocculation-resistant by virtue of a stabilizing adsorbed layer of NC resin on the pigment particle surfaces. The pigment particles are large aggregates of crystals, from which additives such as abietyl resin have been shown to dissolve off into the ink medium. The aggregates are associated with liquid medium immobilized within the shear boundary near the pigment/medium interface (includes adsorbed layers and liquid within pores). This results in the effective pigment volume fraction in the ink being higher than that calculated from the weight fraction. When considered in terms of the effective volume fraction, most of the pigments have the same critical concentration of about 0.2–0.25. This indicates that deterioration in flow at higher concentrations is due in the first instance to crowding of particles, rather than to the failure of the mechanism of flocculation resistance per se. The robustness of the flocculation resistance is indicated by a low rate of increase of the strength of the structure with an increase in the effective volume fraction above the critical concentration. Robustness is important in maintaining manageable flow at high concentrations. Increasing the proportion of ethyl acetate in the solvent blend can adversely affect the millbase rheology of dispersions of some pigments in NC ink media due to induced flocculation and structure formation. The improved solvency of the blend for NC resin has been shown to reduce the amount of NC resin adsorbed on the particles of an ester-sensitive pigment. Other pigments give inks with rheology insensitive to ester content. This is attributed to more specific interaction of the NC resin with the pigment particle surfaces. The effect of temperature on flocculation resistance is consistent with these views.     

Recent studies of particle packing in organic coatings

Organic coatings often contain sufficient pigmentation that the pigment volume concentration (PVC) and the critical PVC (CPVC) must be carefully considered. Past work has shown that the CPVC can be identified with the random densest packing of pigment particles after considerations of the adsorbed polymer layer on the particles is taken into account, and that this packing can be predicted by empirical particle packing algorithms developed for mixtures of particle sizes. Recent studies have shown that local fluctuations of pigment and polymer concentrations in a film can lead to local film volumes that can exceed the CPVC even though the average PVC for the whole film (the global PVC) is below the CPVC. These effects are consistent with observations of void formation in films below the CPVC, and can be analyzed by local film statistics. We have also recently performed simulations of particle packing by the compression of multiple hard spheres that allows further insight into local concentration fluctuations in PVC within a film.     

Attributes of the latex emulsion processing and its role in morphology and performance in paints

This article explores the influence of process variation and neutralization of itaconic acid (IA) on polymer properties and paint performance. The study elaborated how the reaction pathway changes the acid distribution in the latexes. The study also investigated the influence on paint performance of degree of neutralization of IA before its incorporation into emulsion. The acid distribution study was done through the conductometric titration method. Latex film properties were studied through differential scanning calorimeter (DSC) and minimum film forming temperature (MFFT). These latexes were formulated in the corresponding paint and study was done using scanning electron microscopy (SEM), which was further correlated with the performance properties of the paint such as scrub, gloss, whiteness and contrast ratio.     

Properties of calcined kaolins in anticorrosion paints depending on PVC,chemical composition and shape of particles

The properties of calcined kaolins in paints were identified in relation to their pigment volume concentration (PVC). The study involved three kinds of kaolin exhibiting different development of the lamellar structure of primary particles as well as different distribution of particle size. Kaolins also displayed varying contents of a glassy phase – mullite and quartz. Prepared model paints were formulated with the increasing content of kaolins, with PVC ranging from 5 to 40% up to a maximum critical pigment concentration (CPVC), i.e. up to a point where PVC = CPVC. The properties of paints were tested by means of laboratory corrosion tests in the environments of neutral salt mist and of condensed humidity. It was the aim of the study to identify the effect of kaolin's PVC on the mechanical and corrosion resistance of coatings based on water-borne epoxy resin.     

Stability of pigment and resin dispersions in waterborne paint

The stability of a colloidal dispersion in a waterborne paint system, which consists of dispersed pigment and polymeric particles (dispersion or emulsion) along with a water-soluble acrylic polymer, was investigated. It was found that adsorption of appropriate ultrafine particles to the relevant particles could stabilize these particles against flocculation, leading to lower viscosity and yield value. The gloss and smoothness of the resultant films are notably improved. As the stability of the colloidal particles in an aqueous system is strongly dependent on the electrostatic effect, the effect was evaluated by measuring the ζ-potentials of the relevant colloidal particles. The ζ-potential is the electric potential on the outside of the surface layer, which includes the counterions around the particle. The ζ-potentials of a series of pigments in a solution of a water-soluble polymer were determined. By arranging the pigments according to their ζ-potentials, an order of basicity-acidity was established for pigments in a waterborne system, and the order was found to be different from that of solventborne systems, thought to be due to adsorbed counterions. After dispersing the pigment sufficiently with an appropriate polymer dispersant, ultrafine particles (of size under 0.05 μm) of lower refractive indexes were adsorbed to the surface of the pigments and polymeric particles. The adsorption layer of ultrafine particles can modulate the ζ-potentials of various colloidal particles to bring them into a certain range, so that the co-flocculation tendency between different colloids is remarkably diminished providing quite stable paint compositions by both electrostatic and steric hindrance effects.     

A new type of quaternary ammonium salt containing siloxane group and used as favorable dispersant in the surface treatment of C.I. pigment red 170

C.I. pigment red 170 is an important type of organic pigment. A new type of quaternary ammonium salt containing siloxane group was prepared and then used as a favorable dispersant in the surface treatment of pigment red 170. The quaternary ammonium salt was achieved from the reaction of N-(β-aminoethyl)-γ-aminopropyl-methyl-bimethoxy-silane and 3-chloro-2-hydroxypropyl-bimethyl-hexadecyl ammonium halide in isopropanol, and its structure was characterized by IR and NMR techniques. The flowability, dispersing extent, particle size, and wetting behaviors of pigment were determined and the results showed that a small amount of the above dispersant could bring to the high flowability, good dispersing stability, small particle size and excellent wettability of pigment red 170. We also proposed the scenarios of dispersing process of pigment red 170 based on the information obtained from above characterizations.     

颜填料体积浓度的用量对涂料保色性的研究

阐述了配色原理,分析了不同PVC用量对涂膜的附着力、硬度、耐水、耐酸等性能的影响,得到PVC的用量在48%时,涂料的各种性能达到最佳,同时还给出了用来配深、中、浅各种颜色的白色涂料PVC的范围及相应的色浆用量,采用控制颜填料体积浓度的用量,解决了涂料保色性的问题;通过扫描电镜分析、粒度分析对比,观察了涂料的外貌和平均粒径,结果表明,在PVC为48%时,涂料的分散效果及稳定性均好。     

国内功能涂料的研究进展

介绍了国内功能涂料方面的研究进展,包括水性防火阻尼双功能涂料、低发射低反射涂料、电热涂料、长大型隧道用多功能纳米涂料、电磁波屏蔽涂料、智能控温涂料、氧化石墨烯/聚氨酯复合紫外光固化涂料、调湿抗菌涂料、隔热/耐磨透明涂料、太阳热反射涂料、转移涂料、自闭性聚合物水泥防水涂料、低VOC(挥发性有机物)常温固化氟碳涂料、水性硅藻内墙净化功能涂料、多功能净味绿色涂料、带湿带锈涂料、干粉质感涂料、抗碳化涂料、发光涂料、防涂鸦抗粘贴涂料等。     

The effects of water soluble polymers on paper coating consolidation

The consolidation process of wet paper coating layers has been generally divided into several stages by the definitions of first critical concentration (FCC) and second critical concentration (SCC), however few works have been done on the kinetics of water expelled during drying and its influence on the critical concentrations. In this paper, the effects of three kinds of water soluble polymers, i.e., carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA) and modified coating starch, on the consolidation of model kaolin clay-latex coatings were investigated. On-line water evaporation loss rate, together with the level of FCC and time needed to reach FCC, was characterized. The results showed that water evaporation loss weight increased almost linearly with drying time during the initial wet coating layer consolidation stage. On-line water evaporation rate and the value of FCC decreased with water soluble polymers addition, while the time needed to reach FCC became longer. Among the three polymers studied, CMC was the most effective, then PVA and starch.     

A mechanistic study of the effect of pigment loading on the appearance of powder coatings: The effect of surface topography on the optical properties of powder coatings: Modelling and experimental results

Gloss is a critical property for many powder coating applications and is related to the amount of light reflected by the coating layer on a substrate. Gloss of powder coatings can, depending on the composition, vary from excellent to matt. It is well known in the powder coatings industry that increasing loadings of pigment, especially TiO₂, causes a detrimental loss of gloss. In order to understand the cause of this phenomenon two questions have to be addressed: firstly, what is the relation between the optical properties and the surface topography of the powder coating and, secondly, how do the powder coating composition and curing conditions affect the surface topography? In order to answer the first question, the typical features of the surface of a cured powder coating have been studied in detail. Using a white light interferometer, it has been shown that the surface topography consists of both short wave and long wave patterns. Each of these patterns could be described by using two statistical parameters only, the root mean square height of the roughness and its correlation length. The effect of both the short and long wave roughness on the gloss has been simulated with a single wave pattern model, based on an approximation of the Kirchoff scattering theory [9]. These simulations illustrated that neither the short nor the long wave roughness on itself determines the optical properties. In order to quantify the combined effect of the long and short wave surface features a two-scale modelling approach was followed. The predictions of this model were in good agreement with experimental gloss data of coatings containing different amounts and types of pigments.     

Effect of ultrasonic treatment on structure and properties of ethylhydroxyethylcellulose polymer adsorption layer on inorganic pigments in aqueous dispersion

The course and the result of the surface modification of titanium dioxide and ferrous oxide pigments in aqueous dispersion by ethylhydroxyethylcellulose (EHEC) without and with mechanical treatment of the dispersion by ultrasonic power was studied by the electrokinetic sonic amplitude (ESA) method. The evaluation of the ESA data showed that the ultrasonic treatment causes a significant thickness increase of the EHEC layer on the pigment which is primarily attributed to the ultrasonically induced activation of the pigment surface. The thickness of the polymer adsorption layer derived from ESA measurements was confirmed by TEM investigations. The ultrasonic treatment leads to significant changes of the properties of the adsorption layers and is a promising method for the surface modification of pigments with regard to dispersion stability.     

正交试验在水性带锈涂料配方设计中的应用

研制了一种水性带锈涂料，通过分析影响涂层附着力、硬度的主要因素，运用正交试验得到涂料的最优配方。试验结果表明，该涂层附着力达到0级、硬度为3H、耐水性好，具有一定的应用价值。