水性双组分氟丙烯酸—聚氨酯涂料的研制及性能测试

介绍了水性双组分氟丙烯酸-聚氨酯涂料所用原料及其预处理,水性双组分氟丙烯酸-聚氨酯涂料的羟基组分采用两步法合成:第一步合成了具有大分子表面活性剂性能的水性聚氨酯,在合成的过程中引入了双键和羟基组分;然后采用无皂乳液聚合的方法合成了以氟丙烯酸酯为核、聚氨酯为壳的水性树脂。并列举了采用该树脂与水性固化剂配合研制的清漆的性能指标,该清漆有着非常广泛的用途,讨论了影响涂料性能的各种因素。该双组分清漆水性含氟丙烯酸酯-聚氨酯清漆具有优异的综合性能。     

氟、硅改性聚氨酯材料的研究进展

聚氨酯(PU)是一类用途广泛的工程材料,但用传统原料和方法制备的聚氨酯也存在诸多缺点,如耐热性、耐侯型不好,从而限制了它在工程技术领域的进一步应用。为此,聚氨酯的化学改性成为该领域的研究热点之一。作者综述了近年来氟、硅化学改性聚氨酯方面的研究进展,并对今后的研究发展进行展望。     

乳化体系对氟硅改性丙烯酸酯乳液性能的影响

采用不同的乳化体系来制备氟硅改性丙烯酸酯乳液,主要探讨了乳化体系对预乳化液稳定性、聚合稳定性、储存稳定性、转化率、粒径大小与分布以及吸水率的影响。结果表明,在所采用的乳化体系中,由聚氧乙烯-4-酚基醚硫酸铵盐(CO436)与1-丙烯基-α-羟基烷基磺酸钠(COPS-1)组成的复合乳液体系,可制得转化率高达98.85%的稳定乳液,乳液粒径呈单分散分布,乳胶膜的吸水率只有4.31%。     

Scratch behavior of nano-alumina/polyurethane coatings

Incorporating metal-oxide nanoparticles such as nano-alumina and nano-silica into polymer coatings to enhance mechanical durability is widely utilized in the current antiscratch and mar technologies. In this article, a quantitative study of the effect of a nano-alumina additive on the surface mechanical properties and scratch behavior of a two-part polyurethane coating is reported. An instrumented indenter with a conical diamond tip is used to measure surface mechanical properties (modulus and hardness) and to perform scratch tests, over a wide range of scratch loads. The scratch behavior in terms of the onset of elastic–plastic transition and scratch morphology were characterized by laser scanning confocal microscopy. The scratch results were correlated to the surface mechanical properties and relevant bulk material properties to understand the overall scratch behavior of the coatings. The results show that the scratch behavior of the coatings depends strongly on the concentration of nano-alumina.

Application of a silicone-modified acrylic emulsion in two-component waterborne polyurethane coatings

Two-component waterborne polyurethane (2K WBPU) coatings were prepared using a silicone-modified acrylic emulsion as the hydroxyl component, and hydrophilically-modified polyisocyanate as the curing agent. The effects of the levels of silicone monomer and hydroxyl values on the film properties of the 2K WBPU coatings were investigated. Infrared spectroscopy characterized its structure. Scanning electron microscopy (SEM), thermo-gravimetric analysis (TGA), and differential scanning calorimetry (DSC) were used to study the surface morphology and the thermal stability of the film. The results showed that the performance of the coatings and the thermal stability of the film of 2K WBPU were improved after silicone modification.     

Preparation and properties of polyurethane coatings based on acrylic polyols and trimer of isophorone diisocyanate

This paper presents a study on the effect of NCO/OH ratio and an increase in hydroxyl content of acrylic polyols on the properties of polyurethane (PU) coatings. Coating properties studied are gloss, scratch resistance, flexibility and adhesion, mechanical properties include tensile strength, modulus, percent elongation and Shore hardness, while physicochemical properties include chemical resistance and solvent absorption of coated PU samples. A series of acrylic polyols (copolymers) based on butyl acrylate (BA), methyl methacrylate (MMA), styrene and 2-hydroxy ethylacrylate (HEA) were prepared by selecting different percentage of hydroxyl content. Trimer of isophorone diisocyanate (IPDI) was also synthesized in the laboratory. This trimer has trifunctionality. Isocyanurate ring of trimer increases thermal properties of PU. Polyurethanes from these acrylic polyols (containing different percent hydroxyl) and trimer of IPDI were prepared with two different NCO/OH ratios viz, 1.1:1 and 1.2:1. Polyurethanes were coated on substrates for measuring coating properties. Mechanical properties were measured on cast films of the PUs. The experimental results revealed that all polyurethane coatings based on acrylic polyols and IPDI trimer showed good gloss, scratch resistance and excellent adhesion. Thermal stability of these PU samples was found to be better. Physicochemical properties reflected that these PU have excellent chemical and solvent resistance.     

EIS study on failure process of two polyurethane composite coatings

The performance of acrylic polyurethane composite coating and aliphatic urethane composite coating in 3.5% NaCl solution under ultra-violet radiation was studied with methods of EIS, SEM and FTIR. For aliphatic polyurethane coating, the coating resistance decreased and the coating capacitance and porosity increased more quickly than acrylic polyurethane coating. The acrylic polyurethane composite coatings showed better performance than aliphatic polyurethane composite coatings. IR spectra showed that under UV irradiation conditions, the failure mechanism of the two polyurethane coatings was the transformation of sec-amide to primary amides. The fractured bonds in acrylic polyurethane were mainly C–O bonds, while in aliphatic polyurethane they were mainly C–N bonds. The lower protection property of aliphatic polyurethane coating may be mainly attributed to the C–N bonds which are more liable to be broken.     

Optical and mechanical properties of transparent acrylic based polyurethane nano Silica composite coatings

The aim of this work is to investigate the effect of two types of nano Silica (precipitated and fumed) with various concentrations on the optical and mechanical properties of transparent polyurethane acrylic based nano composite coatings. Transparency, gloss, UV absorption, adhesion strength and impact resistance of the samples have been measured. The gloss of the film samples remains unchanged compared to the reference film sample up to 2 wt.% (weight percent) for both types of nanoparticles. The samples containing 4 and 6 wt.% nano Silica show reduction in the gloss property by 4.3% and 5.3%, respectively, for fumed samples and 1.8% and 23% for precipitated samples. The film samples show increase in light absorption in the wavelength region of 250–2000 nm by increasing the content of nano Silica. Also cross cut and pull-off test results show that a good adhesion to steel can be obtained (5B for cross-cut, 7 MPa for pull-off) and no changes in impact strength of the samples with respect to the reference have been observed.     

Effects of additives on the performance of two-component waterborne polyurethane coatings

The effects of various additives and solvents on a coating’s performance in a two-component waterborne polyurethane coating system are studied using a statistical experimental design method. Using a blocked arrangement of fractional factorial design matrices, six different independent variables, including the use of different additives, catalysts, as well as solvents at different levels, were examined for their effects on various coating performance parameters, such as gloss, hardness, viscosity, and chemical resistance. Statistical analysis revealed several significant effects of these additives on the coating performances. Most importantly, several two-factor interactions between additives were also found to significantly influence the performance properties of the coating. These interactions could be very difficult to detect using traditional one-at-a-time experimental approaches. The information obtained from this study could be used for designing coating systems with superior performance properties. Presented at the 26th International Waterborne, High-Solids and Powder Coatings Symposium, February 10–12, 1999, New Orleans, LA. Coatings and Colorants Division, 100 Bayer Rd., Pittsburgh, PA 15205-9741.     

Ageing behavior of acrylic polyurethane varnish coating in artificial weathering environments

Polyurethane-based coatings reinforced by ZnO nanoparticles (about 27 nm) were prepared via solution blending. The ZnO/PU films and coats were fabricated by a simple method of solution casting and evaporation. The mechanical properties of the films were investigated by a universal material test, and the abrasion resistance of the prepared coats was evaluated by a pencil-abrasion-resistance tester. It was found that significant improvement of the PU films in Young’s modulus and tensile strength was achieved by incorporating ZnO nanoparticles up to 2.0 wt%, and that the abrasion resistance of the PU coats was greatly enhanced due to the addition of ZnO nanoparticles. Moreover, the antibacterial property test was carried out via the agar dilution method and the result indicated that PU films doped with ZnO nanoparticles showed excellent antibacterial activity, especially for Escherichia coli.     

Effects of ZnO nanoparticles on the mechanical and antibacterial properties of polyurethane coatings

Polyurethane-based coatings reinforced by ZnO nanoparticles (about 27 nm) were prepared via solution blending. The ZnO/PU films and coats were fabricated by a simple method of solution casting and evaporation. The mechanical properties of the films were investigated by a universal material test, and the abrasion resistance of the prepared coats was evaluated by a pencil-abrasion-resistance tester. It was found that significant improvement of the PU films in Young’s modulus and tensile strength was achieved by incorporating ZnO nanoparticles up to 2.0 wt%, and that the abrasion resistance of the PU coats was greatly enhanced due to the addition of ZnO nanoparticles. Moreover, the antibacterial property test was carried out via the agar dilution method and the result indicated that PU films doped with ZnO nanoparticles showed excellent antibacterial activity, especially for Escherichia coli.     

丙烯酸/蓖麻油聚氨酯耐磨涂料的研究

介绍了丙烯酸/聚氨酯涂料的制备和性能测试工艺流程以及蓖麻油改性TDI制备聚氨酯、丙烯酸树脂和丙烯酸改性聚氨酯涂料的合成步骤。通过正交实验对羟基丙烯酸树脂和耐磨性填料———二硫化钼、氧化铬和聚四氟乙烯的用量进行了优化,获得了涂料的最优化配方(用质量分数表示):A组分:聚氨酯3%,醋酸丁酯3%;B组分:羟基丙烯酸1.5%,二硫化钼0.3%,三氧化二铬0.4%,聚四氟乙烯0.6%,混合溶剂5%,十二烷基硫酸钠0.12%,KH-5500.025%,二丁基二月桂酸锡0.0125%。所得涂膜的表干时间约为30min,实干时间约为36h。涂层的附着力1级,硬度1B。在3.3kg的载荷下,磨轮旋转1500圈后,涂层磨痕弦长6.5mm,说明涂料耐磨性优良。试样在质量分数分别为5%和15%的盐酸、氢氧化钠溶液中浸泡一周后,涂层无起泡、润胀和脱落现象,说明涂层耐蚀性优良。     

Effect of surface microstructure on the hydrophobicity of coatings

In this paper, coatings adopted SiO₂ nanoparticles ranging from 1 wt% to 7 wt% were in situ polymerized with low surface energy polymer, and different surface microstructures were built automatically during painting film. Copper microstructure surface was also achieved by chemical etching method and then was modified by low surface energy resin as contrast. The contact angle and the peel strength between the coating and bio-gooey simulacrum were studied. The results showed that the hydrophobicity of the coating was remarkably affected by the surface microstructure. The coating containing 5 wt% SiO₂ nanoparticles was covered with micro- and nano-scale salience and holes, and had the maximum contact angle and the minimum peel strength. Copper slices presented uniform micron and sub-micron structure surface when etching for 15 min and the contact angle reached a maximum of 125° after being modified.     

Effect of particle size distribution on the performance of two-component water-reducible acrylic polyurethane coatings using tertiary polyisocyanate crosslinkers

A two-component waterborne polyurethane system with a 250 g/l VOC has been formulated to meet the performance requirements of the automotive refinish market. This paper discusses an experimental study to develop a two-component water-reducible polyurethane coating using a tertiary aliphatic polyisocyanate crosslinker with dry times, appearance, and reactivity equivalent to a two-component solventborne system. The effects of acrylic polyol monomer composition, glass transition temperature (T_g), and hydroxyl concentration on drytime and ambient cure film performance have been determined. The effects of particle size distribution of the formulated coating on performance were examined. It was found that smaller particle size provides overall improved film properties, i.e., faster dry time, increased hardness, and faster development of solvent resistance. The relationships of both acrylic polyol composition and formulation variables on the particle size distribution are discussed. Presented at 76th Annual Meeting of FSCT in New Orleans, LA, on Oct. 11–16, 1998. 1937 West Main Street, Stamford, CT 06904.     

水性聚氨酯与丙烯酸酯共聚乳液的研究

用乳液聚合的方法 ,制备出了具有核壳结构的水性聚氨酯与丙烯酸酯共聚乳液 (PUA乳液 ) ,对PUA的性能进行了初步的研究。结果表明 ,丙烯酸酯的用量对吸水率、热性能和机械性能产生重要的影响     

Effects of unsaturation and different ring-opening methods on the properties of vegetable oil-based polyurethane coatings

A variety of vegetable oil-based, waterborne polyurethane dispersions have been successfully synthesized from different vegetable oil polyols exhibiting almost constant hydroxyl functionalities of 2.7 OH groups per molecule. The vegetable oil polyols, which have been prepared from vegetable oils with different fatty acid compositions (peanut, corn, soybean, and linseed oil), range in residual degree of unsaturation from 0.4 to 3.5 carbon–carbon double bonds per triglyceride molecule. The effects of residual unsaturation on the thermal and mechanical properties of the resulting polyurethane films have been investigated by dynamic mechanical analysis, differential scanning calorimetry, and thermal gravimetric analysis. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) has been used to accurately determine the molecular weight and mass distribution of the vegetable oil polyols. Higher residual unsaturation results in polyurethane films with increased break strength, Young's modulus, and toughness. This work has isolated the effect of unsaturation on vegetable oil-based polyurethane films, which has been neglected in previous studies. The effect of different oxirane ring opening methods (methanol, butanol, acetic acid, and hydrochloric acid) on the properties of the coatings has also been examined.     

聚氨酯型不饱和聚酯涂料的研究

通过对反应过程中和涂膜酸值和粘度测定以及涂膜性能测定和红外光谱分析研究了聚氨酯型不饱和聚酯树脂的反应温度、反应时间、醇酸比、TDI用量、饱和酸与不饱和酸配比、交联剂聚苯乙烯用量等对涂料性能的影响。研究表明:反应温度170℃,反应时间3 h,乙二醇、邻苯二甲酸酐与顺丁烯二酸酐物质的量比为1.4:3:7,—NCO与—OH物质的量比为1:1,每15 g树脂中加入交联剂苯乙烯5 g,固化体系0.3 g,填料10 g,可制得物理力学性能较好的聚氨酯型不饱和聚酯涂料,涂膜硬度为5 H,附着力1级,柔韧性0.5 mm,抗冲击性50 cm。     

Effects of UV degradation on surface hydrophobicity, crack, and thickness of MWCNT-based nanocomposite coatings

Surface degradation is a common problem in polymeric coatings when they are exposed to sunlight, moisture, and oxygen. In order to reduce their surface degradation, thus keeping the coatings’ original properties, multi-wall carbon nanotubes (MWCNTs) were added, and the coatings were exposed to UV light and salt fog for various lengths of time. At 0 days of UV exposure, contact angle values of 0%, 0.25%, 0.5%, 1%, and 2% MWCNT-based nanocomposite coatings of 75 μm (∼3 mil) thickness were between 85° and 89°. However, after 16 days of UV exposure, contact angle values of the same samples were reduced to 11°, 13°, 34°, 50°, and 54°, respectively. Longer UV exposures resulted in several microcracks on the surface of the coated samples in the absence of nanoscale inclusions, while very minimal cracks or degradation appeared on the MWCNT-loaded samples. Test results also showed that UV exposure along with salt fogging reduced the coating thickness up to 24% at 0% CNTs; in contrast, this reduction was only 7% with a 2% MWCNT coating. These results clearly indicate that MWCNTs added to polymeric coatings reduce UV degradation, lessen surface cracks, protect the film thickness, and hence increase the lifetime of the polymeric coatings.     

水性聚氨酯涂料的制备与性能研究

以甲苯-2,4-二异氰酸酯(TD I)、聚醚Ng 210和二羟甲基丙酸(DMPA)为主要原料,制得不含或含少量有机溶剂的水性聚氨酯乳液,研究了NCO/OH的摩尔比、DMPA含量等对水性聚氨酯乳液性能的影响。结果表明,当NCO∶OH(摩尔比)=2.5∶1,DMPA=5%时,乳液性能最佳。     

双组份水性氟涂料存放时间的研究

为了研究太阳能电池背板用水性含氟涂料的存放时间,将水性FEVE氟涂料双组份树脂与亲水改性六亚甲基二异氰酸酯(HDI)按比例混合,分别于15℃和30℃放置12h内测其粘度、涂膜附着力、耐溶剂及湿热、紫外老化后涂膜附着力、耐溶剂性能;涂布液粘度随存放时间而增大,30℃放置条件下涂布液粘度增大现象更加明显;涂布液放置12h内涂膜附着力、耐溶剂性良好,但其耐老化性能在涂布液放置4～6h开始下降,因此不能根据涂膜耐溶剂和附着力判断涂布液的存放时间。