Synthesis of thermally stable high gloss water dispersible polyurethane/polyacrylate resins

Design and synthesis of some new thermally stable polyurethane/polyacrylate blend resins with high gloss and excellent chemical resistivity has been accomplished. Thus, polyurethane was synthesized from polyethylene glycol (PEG) and hexamethylene diisocyanate (HDI) using the conventional prepolymer method. The double bond functionality is introduced by blocking the prepolymer isocyanate groups with acrylamide so as to utilize acrylic acid as a chain extender to make the resin water dispersible. Polyacrylates are prepared by free radical (emulsion seed) polymerization of methylmethacrylate (MMA), 2-ethylhexylacrylate (2EHA), butylacrylate (BA) and acrylic acid using potassium persulfate (KPS) as an initiator. The morphology of polyurethane and polyacrylate is investigated using FTIR spectroscopy and the thermal stability by TGA. The luster of resin is checked by novo gloss meter. Chemical resistivity of the resin films is determined by immersing the films in different solvents. The rationale of current work was to synthesize some high gloss blend resins from some commonly available monomers, having excellent properties suitable for commercial applications.     

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.     

丙烯酸酯聚氨酯乳液涂料的研制

通过乳液共聚制得了丙烯酸多元醇，再和甲苯二异氰酸酯内乳化法制得预聚体，用二羟甲基丙酸进行扩链，制得丙烯酸酯聚氨酯乳液涂料树脂。该涂料树脂制得的涂膜的强度、丰满度、光泽、硬度等综合性能均优于传统的同类树脂。讨论了合成过程中各因素对树脂及其涂膜性能的影响。     

双组分水性聚氨酯涂料的制备与性能测试

选用水性羟基丙烯酸分散体为成膜物质,水可分散型异氰酸酯（HDI三聚体）为固化剂,以钛白粉为颜料,搭配合适的助剂,制备了干燥快、光泽高、耐候性优异及低成本的双组分水性聚氨酯涂料。考察了颜基比、固化剂的量对涂膜性能的影响,通过涂料体系颜料体积浓度的计算,推导出PVC的倒数与P/B的倒数呈一次线性函数关系。     

Characterization of a hybrid nano-silica waterborne polyurethane coating for clay bricks

A transparent hybrid organic–inorganic waterborne coating was evaluated for the protection of clay bricks. The nanocomposite film was prepared by combining an environmentally friendly process based on UV-curing of water-based acrylic resins and a mild thermal treatment to form nanosilica in situ from alkoxysilane precursors. Coated and uncoated facing bricks were compared by scanning electron microscopy, surface profilometry, water wettability, and capillary rise tests. The hybrid coatings act as a moderate water repellent; interestingly, no appreciable alteration of the aesthetic properties of the brick was observed, in particular no gloss or color change appeared after the treatment.     

高耐候性聚硅氧烷涂料的研制

以高硅含量、高固低黏的改性聚硅氧烷树脂为基础,制备了聚硅氧烷涂料,并用氨基硅烷固化,制得改性聚硅氧烷涂层。考察了氨基硅烷固化剂用量和种类对聚硅氧烷涂层老化失光和变色行为的影响规律。研究结果表明:在改性聚硅氧烷树脂固定不变的情况下,可通过固化剂的种类和用量调节聚硅氧烷涂料的耐老化性。聚硅氧烷涂料具有远优于聚氨酯涂料的耐老化性和耐盐雾性,可作为氟碳面漆的理想替代品。     

常温固化FEVE氟碳涂料耐候性地区差异研究

通过自然老化试验和环境扫描电镜(ESEM),研究并比较了FEVE氟碳涂料和丙烯酸聚氨酯涂料在不同曝晒地区的耐候性差异.结果表明,FEVE氟碳涂料的耐候性远远优于丙烯酸聚氨酯涂料;FEVE氟碳涂料对湿热、盐雾环境较敏感,而对单纯强紫外线照射环境以及工业腐蚀环境不敏感.     

高性能外墙弹性乳胶漆的研制

介绍了一种新型的SiO2杂化水性聚氨酯与丙烯酸酯复合乳液制备高性能外墙弹性乳胶漆配方及工艺,讨论了成膜物质、助剂、颜填料及颜料体积浓度等因素对其涂膜弹性、耐候性、耐沾污性、耐水性等性能的影响。结果表明,研制的高性能外墙弹性乳胶漆各项性能优异。     

聚氨酯涂料的配方设计及PVC计算

采用羟基丙烯酸树脂为成膜物质,钛白粉、超细硫酸钡为颜填料,配用合适的助剂和溶剂,制备了高光泽、耐候性优异及低成本的聚氨酯涂料。考察了颜基比(P/B)、填料、催化剂及紫外线吸收剂对漆膜性能的影响。通过单一颜料涂料体系的颜料体积浓度(PVC)的计算,推导出PVC的倒数与P/B的倒数呈一次线性函数关系。     

高光泽耐高温硅丙树脂改性聚氨酯涂料的研究

用有机硅－ 丙烯酸酯共聚树脂对聚氨酯进行改性，以ＨＤＩ／ＴＤＩ预聚物（ＨＴＰ） 作为交联组分，可制备性能优异的高光泽耐高温硅丙聚氨酯涂料。简述了这种涂料的制备方法和影响其性能的因素     

Synthesis and evaluation of functional polymeric additives with urethane linkage as dispersing agents for preparation of pigment concentrates with high solid loading, low-VOC content, and usefulness for industrial coatings

A synthetic strategy based on precursor and prepolymer approaches has been adopted for preparing the functional polymeric agents with urethane linkage and functional groups such as –CONH–, –COOH, –NH–, C–N, –COOR and C–Cl, that can interact with the pigment surfaces. The agents were tested for their dispersion capacity. High pigment-loaded (as high as 64%) and solvent-free stainers with potential applications in low-VOC paints were successfully prepared. The stainers were mixed with two commercial binder resins—namely epoxy base white and polyurethane metal coat binder resins—to get first paints and their coats on various substrates such as standard glaze paper, tin and mild steel panels. The paint-specific properties, viz. percentage opacity, color strength, solvent resistance, adhesion, scratch hardness and salt spray resistance, were measured to adjudge the suitability of high pigment-loaded coats in industrial applications. The properties measured in general showed improvement in spite of the increase in the pigment loading. The paint coats resisted not only the xylene, petrol, and lubricating oil attack but also humidity and salt spray (up to 1000 h of exposure).     

Eco-friendly zero VOC anticorrosive paints for steel protection

With the growth of the green movement, it is important to prepare environmentally friendly anticorrosive paints to save lot of money, which are lost each year because of corrosion. High molecular weight organic corrosion inhibitor (safe adduct), barrier anticorrosive pigment (safe) and convertible anticorrosive pigment (toxic) are protective elements in paint formulations. Emulsification of the prepared adduct was the way to be applicable in water-borne paints, using mixture of emulsifiers. Surface tension measurements using ring method technique and thermal stability test could characterize the prepared emulsion systems. It was interesting to study the performance of the protective elements in water paint formulations based on short oil water thinned alkyd. Physical and mechanical properties of dry paint films, corrosion tests of the coated steel, water up-take% of the prepared paints, weight loss of steel under paint films after immersion in artificial sea water and corrosion inhibition efficiency of the protective elements were determined. Comparative studies of the protective elements in water-borne paints have been done according to performance, economic feasibility and environmental safety. It was found that zinc chromate as carcinogenic anticorrosive pigment could be replaced by 0.09% of the prepared water-borne corrosion inhibitor (MTDT adduct), 20% micaceous iron oxide (MIO) or their blend. Superior corrosion inhibition efficiency of steel was obtained in case of using MTDT/MIO blend. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

接枝型PUA乳液合成及聚合动力学研究

甲基丙烯酸羟丙酯与水性聚氨酯预聚体反应,得到双烯封端的水性聚氨酯乳液。在乳化剂、引发剂存在下,将丙烯酸酯单体与水性聚氨酯乳液充分混合,并引发聚合,制备了接枝型PUA乳液。TEM观察了PUA乳液的形貌,PUA乳液的粒径在60～120 nm之间;FTIR和NMR表征了合成的PUA结构,显示丙烯酸酯的加入改变了PU本身的氢键相互作用;转化率测试表明,甲基丙烯酸羟丙酯与PU预聚体的反应具有二级动力学特征,而乳化剂的用量影响丙烯酸酯单体与双烯封端聚氨酯乳液的反应速率,反应速率与乳化剂用量符合Rp∝[SDS]0.28。     

Waterborne silicone-organic hybrid coatings for exterior applications

Waterborne alkyd and acrylic resins can be modified with silicone intermediates to improve their weather resistance in paints for exterior applications. The alkyds are modified through copolymerization before dispersion in water, using formulations and process conditions that minimize the tendency to gel. Acrylic latexes can be post treated with selected silicone intermediates at ambient temperature to give hybrid coating binders. In both cases, the gloss retention and chalking resistance of paint films are greatly increased.     

Simultaneous free radical and addition miniemulsion polymerization: Effect of the diol on the microstructure of polyurethane-acrylic pressure-sensitive adhesives

Water-borne polyurethane/acrylic hybrid latexes for their application as pressure-sensitive adhesives were prepared by high solids simultaneous free radical and addition miniemulsion polymerization. In these polymerizations, the polymer network was formed by polyurethane chains that were linked to acrylic chains by the joint reaction of a hydroxyl functional methacrylate and an isocyanate functional polyurethane prepolymer, and by acrylic chains linked among themselves. Under the working conditions, the modification of the polymer architecture was possible by altering the acrylic chains, the polyurethane chains and the links between the polyurethane and the acrylic chains. In the present work, the polymer microstructure was modified by the addition of different diols (polyurethane chain extenders) to the formulation. The effect of the nature of the diol on polymerization kinetics, polymer microstructure and adhesive performance of water-borne PSAs was studied. Adhesive test results demonstrate clearly for the first time that the long-term resistance to shear of an acrylic PSA does not depend only on its gel content but very much depends on the detailed microstructure of the gel inside each particle.     

Application of silica-containing nano-composite emulsion to wall paint: A new environmentally safe paint of high performance

A new emulsion-type paint was prepared by utilizing a nano-composite emulsion (NCE), which contained nano-size particles (ca. 60 nm in diameter) consisting of silica (inorganic core, ca. 30 nm in diameter) and polyacrylate (organic shell), and evaluated as wall paint. By applying NCE for the wall paint, about 35 wt.% of the organic content in the paint could be reduced in comparison with the commodity emulsion-type paint, which is highly effective to save the petroleum resources. The basic properties of the white NCE paint film on gloss, surface hardness, adhesion, and solvent resistance were evaluated and compared with those of acrylic emulsion-type paints as well as those of silica-containing paints which were prepared simply by blending the acrylic emulsion with silica sol. The NCE paint was especially excellent in solvent resistance. Then the practical tests were performed to evaluate its appropriateness as wall paint, which clarified the excellent antipollution property and the high flame resistance of the NCE paint.     

Formulation effects on the distribution of pigment particles in paints

Modern water-borne paints are widely used in different areas of applications ranging from high-gloss lacquers to flat, scrub-resistant interior paints. From this point of view, the pigment volume concentration (PVC) is one key-parameter adjusting the desired application properties. In high-gloss paints, for example, a low PVC is required to accommodate the proper surface roughness to achieve a high gloss. Consequently, a high concentration of TiO₂ is needed to obtain a good hiding power at the same time. Flat paints nonetheless are highly filled due to cost reasons preferentially by CaCO₃ and the pigment binding capacity of the binder is crucial. In this work, paint formulations differing in PVC, and the type of binder or dispersing agent were investigated by various techniques concerning the distribution and aggregation of pigment particles, e.g. TiO₂. To get a detailed insight into the structure of the liquid paints and the corresponding dried paint films, suitable analytical tools were applied for characterization. The structure of the liquid paints was analyzed by remission light spectroscopy (RLS), disc centrifugation, cryogenic-replication transmission electron microscopy (Cryo-replica TEM) and cryogenic-scanning electron microscopy (Cryo-SEM). The pigment distribution in the corresponding dried paint films was examined by means of atomic force microscopy (AFM), TEM and RLS. The tendency of the TiO₂-pigments to form aggregates was found to depend on both: first on the type of binder used in the formulation and second on the employed dispersing agent. It is shown that only by adjusting the properties of the binder in combination with common dispersants, it is possible to get well-distributed TiO₂ particles within the paint. Correlation of application properties, e.g. gloss and blocking to the microscopic structure is presented.     

Effect of different polymers on the efficiency of water‐borne methyl amine adduct as corrosion inhibitor for surface coatings

Styrene/acrylic emulsion copolymer and water‐based short oil urethane alkyd resin were used as binders to prepare water‐based, environmentally friendly paints by using 0.5% emulsified methylamine adduct as corrosion inhibitor. The choice of the two above‐mentioned binders was based on the fact that styrene/acrylic emulsion copolymer is a nonconvertible binder, whereas short oil urethane alkyd resin is a convertible binder. The physical, chemical, mechanical, and corrosion properties of the paint films were evaluated and compared with a commercially known anticorrosive water‐based paint. It was found that the prepared paints have unique desirable properties such as the following: they do not contain anticorrosive pigments (which contain heavy metals in their main chemical structure); they are solvent‐free; and they can be produced to match any color. Corrosion tests on the films of the formulated paints revealed that the short oil urethane alkyd resin is superior to the styrene/acrylic copolymer. Moreover, the corrosion inhibition properties of the paint films prepared from both binders are comparable with the commercially available paints containing anticorrosive pigments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 879–885, 2002     

Synthesis and properties of hybrid alkyd–acrylic dispersions and their use in VOC-free waterborne coatings

Hybrid waterborne alkyd–acrylic dispersions with solid content of 40%, free from any surfactant and exempt of any organic solvent, were successfully synthesized by a melt co-condensation reaction between an acrylic prepolymer bearing carboxylic groups and a long-oil alkyd resin. Spontaneous emulsification of the ensuing hybrid resin was achieved by the addition of an aqueous ammonia solution that neutralized the carboxylic functions. The key role of the carboxylic groups on the stabilization process and on the storage stability of the dispersion was assessed and it was shown that the insertion of anhydride moieties within the acrylic prepolymer ensured the efficient coupling between the acrylic and the alkyd resin and prevented the phase separation. These dispersions are easy to implement and might be used to prepare high quality zero VOC coatings in terms of drying time, stability and gloss. The most stable dispersion was also used in the formulation of air-drying waterborne lacquers and their coating properties were evaluated.     

Effects of pigmentation on siloxane–polyurethane coatings and their performance as fouling-release marine coatings

Siloxane–polyurethane paints were formulated and characterized for coating properties and performance as fouling-release (FR) marine coatings. Paints were formulated at 20 and 30 pigment volume concentrations with titanium dioxide, and aminopropyl-terminated poly(dimethylsiloxane) (APT-PDMS) loadings were varied from 0 to 30% based on binder mass. The coatings were characterized for water contact angle, surface energy (SE), gloss, and pseudobarnacle (PB) adhesion. The assessment of the FR performance compared with polyurethane (PU) and silicone standards through the use of laboratory biological assays was also performed. Biofilm retention and adhesion were conducted with the marine bacterium Cellulophaga lytica, and the microalgae diatom Navicula incerta. Live adult barnacle reattachment using Amphibalanus amphitrite was also performed. The pigmented coatings were found to have properties and FR performance similar to those prepared without pigment. However, a higher loading of PDMS was required, in some cases, to obtain the same properties as coatings prepared without pigment. These coatings rely on a self-stratification mechanism to bring the PDMS to the coating surface. The slight reduction in water contact angle (WCA) and increase in pseudobarnacle release force with pigmentation suggests that pigmentation slowed or interfered with the self-stratification mechanism. However, increasing the PDMS loading is an apparent method for overcoming this issue, allowing for coatings having similar properties as those of clear coatings and FR performance similar to those of silicone standard coatings.