Photooxidative stability provided by condensed tannin additives in acrylic-based surface coatings on exterior exposure

Condensed tannins, also known as proanthocyanidins, have been added as functional additives to acrylic-based clear coatings to promote polymer coating longevity and also stabilize timber color on accelerated and exterior weathering. When added at <?0.5% w/w content, native tannins and tannins modified with maleate groups extended coating performance >?20% compared to commercial hindered amine light stabilizers (HALS) and phenolic stabilizers used at comparable coating loadings. Other tannin chemical modifications such as methylcarboxylate groups were also associated with greater coating longevity beyond that achieved with the synthetic UV and antioxidant additives. This study has also revealed that tannin addition to acrylic coatings can act to photostabilize timber coloring on exterior exposure. While tannin use can contribute color to coatings, any color was rapidly bleached on UV exposure with a dependency on tannin content, degree of modification, and coating formulation pH. Moreover, through manipulating tannin addition levels, this tannin decolorization could offset typical wood darkening associated with UV exposure to provide low or no wood color change over longer exposure periods. With the photooxidative stability efficacy of tannins established on exterior exposure, condensed tannins in native and modified form offer potential as sustainable functional additives for the coatings sector.     

Rheological studies of two component high build epoxy and polyurethane based high performance coatings

The work presented in this article involves the study of rheometric profile of several rheological additives in two-component (2K) high build epoxy zinc phosphate primer and two-component high build aliphatic polyurethane topcoat. Viscosity profile and thixotropic behavior at different shear rates have been determined for both the paints using Physica MCR 301 Rheometer of Anton Paar. The valuable information derived from these measurements led to better insight into the influence of these rheological additives on important paint properties like flow and leveling, sag control, in-can settling during storage, etc. Rheometric results were also compared with the results obtained during the actual application of these experimental coatings on mild steel panels. From the rheological study it was concluded that the thickeners based on surface-modified clay and organically modified castor oil derivative work well in epoxy zinc phosphate primer whereas polyurea-based thickener showed better results than other rheological additives in the case of the 2K polyurethane system. Measurement of low shear and high shear viscosity response of different thickeners helps in predicting storage and application behavior of these coatings which correlates well with the actual observation.     

水性膨胀型隧道防火防霉涂料

以硅丙乳液为基料,以改性聚磷酸铵、三聚氰胺、双季戊四醇、偶氮二甲酰胺为阻燃剂,以钛白粉、硼酸锌、可膨胀石墨为填料,以纳米SiO2为改性剂,在负离子抗菌添加剂和多种助剂配合下,制备的水性隧道防火涂料,具有防火性好、黏附性强、防霉抗菌、防水抗渗、环保无毒、装饰性好、施工方便等特点。     

硼酸盐功能材料研究进展

由于BO3－3中原子以sp2杂化以及p－π共轭的特性使得BO3－3非常稳定且易于发生电子云不对称,有利于产生较大的倍频效应,稀土离子的加入将提高材料的非线性光学性能,因而成为材料领域的研究热点。本文介绍了单金属硼酸盐和多金属硼酸复盐,以及稀土硼酸盐作为功能材料的科研成果和近些年的研究进展,并对硼酸盐功能材料领域的研究进行了展望。     

The effects of inorganic borates on the burning of PVC

The flammability of flexible poly(vinyl chloride) sheet containing barium, calcium and zinc borates, alone and in combination with antimony oxide, was measured by BS2782-508C and ASTM D2863. A statistical comparison of these tests was made. Barium and calcium borates, with or without antimony oxide, had little or no effect on flame retardancy, but zinc had a synergistic effect with antimony oxide. The value of these inorganic borates in reducing smoke is compared using the Stanton Redcroft F.T.B. Unit, an attachment of the manufacturer's Critical Oxygen Index (C.O.I.) test. This test consists of passing the smoke from the C.O.I, test directly into a chamber where the maximum smoke density is measured using a light source and photocell assembly. Formulations containing zinc borate and antimony oxide gave the least smoke. The advantages of zinc borate in flame retardant poly(vinyl chloride) were found to be offset by inferior mechanical and electrical properties and heat stability, unless small amounts of epoxidised oil were added. The degree of hydration of the zinc borate was not critical.     

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.     

醇溶性无机富锌涂料的研制

醇溶性无机富锌涂料是以硅酸乙酯水解液为A组分,聚乙烯醇缩丁醛为B组分基料,配以锌粉以及其他填料、助刺、溶剂等制成。简要阐述了醇溶性富锌涂料成膜机理和对硅酸乙酯水解配方的研究,以及锌粉添加量对防腐性能的影响。     

Studies on Performance of Cured Water-Borne Melamine–Acrylic Emulsion Coatings

In this study, water-borne coating formulations which could be cured quickly were prepared using acrylic emulsion as the major coating constituent and highly reactive melamine resin as curing agent, and further incorporating a variety of additives. Melamine and acrylic types, melamine/acrylic mass ratio in coating formulation, and curing temperature were found to influence the performance of cured coatings. When melamine resin etherified slightly with methanol was used as curing agent, melamine/acrylic mass ratio was 0.45 and the coating formulation was baked at 170°C for 30 s, it was observed that performance of cured coating was the best. FTIR was used to study molecular structural changes of coatings after curing, and to analyze the cure mechanism of the coating. DSC was used to study the range of temperature in which curing occurred. The water-borne coating prepared in this study could be cured quickly when it was applied on decorative paper surface and baked at high temperature. Performance properties of cured coatings were tested according to standard methods, it was observed that dry heat resistance, wet heat resistance, adhesion, pencil hardness, and stain resistance all met standard requirements.     

Deposition of zinc–zinc phosphate composite coatings on steel by cathodic electrochemical treatment

The present work aims at the development of an energy-efficient and eco-friendly approach for the deposition of zinc phosphate coatings on steel. The study describes the possibility of preparing zinc–zinc phosphate composite coatings by cathodic electrochemical treatment using dilute phosphoric acid as an electrolyte and zinc as an anode. The methodology enables the preparation of coatings with different proportions of zinc and zinc phosphate by suitably varying the applied current density, pH, and treatment time. Adhesion of the coating on mild steel and adhesion of paint film on the phosphate coating were found to be good. The surface morphology of the coatings exhibited platelet-type features and small white crystals (agglomerated at some places) which represented zinc and zinc phosphate, respectively. An increase in current density (from 20 to 50 mA/cm²) increased the size of the zinc crystals, and coatings prepared at 40 and 50 mA/cm² resembled that of electrodeposited zinc. Since the proportions of zinc and zinc phosphate could be varied with applied current density, pH, and treatment time, it would be possible to use this methodology to prepare coatings that would offer different degrees of corrosion protection.     

复合外墙涂料的耐候性和耐沾污性研究

以改性纳米硅溶胶和苯丙乳液为基料辅以合适的颜填料和助剂制作成的有机无机复合外墙涂料性能优异。着重讨论了不同PVC涂料如何搭配改性纳米硅溶胶才能取得突出的耐候性和优异的耐沾污性。     

建筑外墙复合型质感涂料的制备与应用

以改性硅丙乳液复合部分弹性乳液为基料,天然石英砂为主要填料,辅以纳米二氧化硅、纳米抗污助剂、空心玻璃微珠、反射隔热粉、多功能助剂等制成建筑外墙复合型质感涂料,其具有抗污、耐候、超耐久及反射与阻热等性能,外观上形象逼真、高贵质感、色彩丰富,施工简便,是一种新型多功能、高性能、高装饰性建筑外墙涂料。     

无机材料对超薄型钢结构防火涂料性能的影响

介绍了晶须、石墨插层化合物、硅微粉、纳米二氧化硅、二氧化钛、硼酸锌等无机材料对超薄型钢结构防火涂料的防火性能、涂膜质量等理化性能的影响,指出以合适的无机新材料在适当的用量下对传统防火涂料进行必要的改性,是进一步提高超薄型钢结构防火涂料各项性能的有效方法。     

油罐专用隔热反射涂料的研制

选择进口空心玻璃微珠研制了一种薄层反光隔热效果优良、耐沾污性和耐候性良好的隔热反射涂料,采用美军军标对其性能进行了评价并与普通聚氨酯涂料进行了比较,表明其效果明显。     

Electron beam irradiation of zinc borate flame retardant containing acrylonite-butadiene-styrene (ABS) composites

The effects of electron beam radiation and zinc borate on the mechanico-physical properties and flame resistivity of magnesium hydroxide (MOH)- acrylonitrile butadiene styrene (ABS) composites have been investigated. The increasing of irradiation dosages has gradually improved the tensile strength and gel content of all samples by inducing the degree of crosslinking networks formed in ABS matrix. Analysis shows that higher amount of zinc borate is desirable to achieve promising tensile strength because zinc borate can attach into the interfaces between MOH particles and ABS matrix. Moreover, the addition of zinc borate could also retard the flammability of ABS as evidenced by LOI results. The crosslinking networks formed could improve fire resistance by reducing the melt dripping phenomenon. This is expected because the crosslinking networks can effectively minimize the oxygen gas to penetrate through the polymer structure to participate actively in the combustion activity.     

开放式透明涂饰工艺探索及漆膜性能分析

分析了水性木器漆在应用过程中存在的优势与不足,深入探索了水性聚氨酯木器漆开放式有色透明涂饰工艺,同时对干燥后的漆膜与溶剂型聚氨酯木器漆漆膜在硬度、耐磨性、耐干热性、附着力、耐冲击性、耐液性等性能上进行了对比。结果表明：所选水性木器漆漆膜在硬度、耐磨性、耐冲击性方面与溶剂型漆膜差别不大,在耐干热性、附着力、耐液性方面相差较大。     

Hydrated and anhydrous zinc borate fillers for tuning the flame retardancy of epoxy nanocomposites

In this study, hydrous (Zn₃B₆O₁₂·3.5H₂O) and anhydrous (ZnB₂O₄) forms of zinc borates were synthesized at 150 and 175°C under moderate pressure conditions (85 and 150 psi, respectively). Synthesized zinc borates were controllably incorporated (1, 5, and 10 wt%) in epoxy resin to prepare their nanocomposites. The flame-retardant and mechanical properties of these nanocomposites were determined and compared in terms of their flame spread testing, smoke density, limiting oxygen index, and flexural strength. Superior properties in terms of flame retardancy were observed for epoxy composites containing hydrous filler as compared to anhydrous zinc borates. Although flexural strength was observed to be decreased with increasing filler concentration, the marked drop is lower for composites with hydrous zinc borate as compared to the anhydrous one. The variations in flame-retardant and mechanical properties of composites with both types of fillers are related to their morphological (field emission scanning electron microscopy), X-ray diffraction (XRD) analysis, Fourier Transform Infrared (FTIR), differential scanning calorimetry, and thermogravimetry analysis and explained with condensed phase mechanism.     

Development of iodopropynyl carbamates as preservatives for paint and coatings

Over the last 100 years, there have been many developments in terminal iodinated acetylene chemistry. Within the iodopropynyl derivatives, it appears that over the last 30 years iodopropynyl carbamates have attracted the most attention in research, development, and industrial applications as preservatives for material protection. This article provides an overview of the chemistry and antimicrobial profiles of specific iodopropynyl derivatives suitable for use in paint and coatings as fungicides, bactericides, and algaecides. Recent chemical and antimicrobial developments of these very effective and broad spectrum 3-iodo-2-propynyl carbamate preservatives for in-can preservation, dry film protection, and marine paint are discussed. P.O. Box 165, Basking Ridge, NJ 07920.     

巴士客车用丙烯酸聚氨酯罩光清漆的制备

介绍了以聚酯树脂和特种助剂对罩光清漆进行改性,制得了适合巴士客车使用的丙烯酸聚氨酯罩光清漆。分析了聚酯树脂和特种助剂对罩光清漆的丰满度、抗划伤性能、流平性和施工性能的影响。结果表明当选用高固含、高羟基聚酯树脂对丙烯酸树脂进行改性时,涂料具有较好的丰满度和抗划伤性能;当流平剂选用丙烯酸类和有机硅类搭配使用时,可大大提高罩光清漆的流平性能;当触变剂BYK-410的用量为0.3%时,清漆一次涂装干膜60μm不流挂,当DBE慢干剂用量为2%时,涂料具有好的施工性能。     

有机-无机(硅溶胶)复合涂料的制备

有机-无机(硅溶胶)复合涂料，既具有硅溶胶耐候性好、硬度高、附着力强、耐水、耐碱、耐沾污等特点，又具有有机聚合物成膜性好、韧性大、光泽高等特点。本法选用江阴国联化工有限公司生产的交联改性的苯乙烯-丙烯酸酯乳液与硅溶胶通过物理混拼法，并辅以适当的颜填料、助剂制备的涂料，可作为外墙封闭型底漆用于水泥砂浆、混凝土等硅酸盐基材及用于外墙装饰。文章还述及制备工艺及注意事项。     

锌及镀锌层稀土转化膜研究进展

锌及镀锌层表面稀土转化膜具有良好的耐蚀性能和无毒、无污染等优点,是最有希望替代铬酸盐处理的转化膜之一,具有良好的发展前景.本文综述了国内外关于锌及镀锌层上单一稀土转化膜的成膜工艺及其机理,并概述了国内外稀土复合膜的研究成果.