Influence of coating system composition on moisture dynamic performance of coated wood

Model coatings with known composition were assessed for liquid water permeability both as single coat systems and combined as primers and topcoats to form regularly used coating systems—in total 38 different systems. The water permeability of the coatings, expressed as water absorption value, was measured by a method similar to the method that now is proposed as a European standard for the assessment of liquid water permeability. During artificial weathering, the samples were measured for a water absorption value, thus showing the change in water permeability as a function of weathering. The study has shown that an excess of surfactants in the alkyd emulsions has a negative effect on the coating’s ability to exclude water from the test samples. A waterborne acrylic paint based on a dispersion of larger particle size (0.4 μm) showed a poor ability to exclude water compared to a similar paint based on smaller dispersion particles (0.1 μm). The alkyd emulsion paints, as single coats, showed high water absorption values compared to solventborne paints and acrylic paints. P.O. Box 5609, SE 114 86 Stockholm, Sweden     

Fast drying cobalt-free high solids alkyd paints

The drying of trade sales alkyd paints at adverse conditions has always been critical. Several routes are available for improving the physical drying properties of alkyd paints at low temperatures. Unfortunately, these approaches will always result in an increase in the VOC of these paints, which is not desired for high solids alkyd paints. Therefore, a new curing mechanism has been developed within Akzo Nobel Decorative Coatings for the improvement of the drying of high solids alkyd paints at adverse conditions.     

Adhesion of waterborne paints to wood

Using a modified torque technique, statistically significant differences in adhesion values were detected for waterborne model paints on wood as a function of moisture content, waterborne preservative, and after fungal inoculation. Change in a paint constituent sometimes resulted in a significant change in the adhesion value. The adhesion values of the alkyd emulsion paints tested decreased after inoculation with a blue stain fungus. On the contrary, the adhesion values of the acrylic dispersion paints tested became significantly higher after inoculation. Wood Biology Section, Department of Forest Products, P.O. Box 7008, S-750 07 Uppsala, Sweden.     

Microautoradiographic studies of the penetration of alkyd, alkyd emulsion and linseed oil coatings into wood

The penetration of wood coating primer products into pine and spruce softwood was evaluated with microautoradiography.¹⁴C-labeled binders of alkyd and linseed oil were synthesized and used in eight different products. The penetration front in wood is uneven due to a heterogeneous structure with different types of wood cells. It was demonstrated that conventional solventborne alkyd primers and waterborne alkyd emulsion primers have similar ability to penetrate into wood. Improved penetration was found for products with lower viscosity, such as an alkyd stain and a linseed oil coating. A priming oil had superior penetration. Generally better penetration was obtained for coatings applied onto sawn and rough surfaces as compared to planed and smooth surfaces. Box 5609, S-11486 Stockholm, Sweden. P.O. Box 160, 2001 Lillestr?m, Norway. Box 5607, S-11486 Stockholm, Sweden.     

Investigating Effect of Conventional and Nano Zinc Pigments on Air-Drying Property of Palm-Stearin-Based Alkyd Resin Paints

Air-drying white paint based on palm stearin alkyd resin was prepared with conventional and nano-ZnO and ZnS pigments. The effects of used pigments on air-drying time and some physical-mechanical characteristics of the paint were investigated by comparing them with conventional counterparts. It was found that ZnS has little effect on the drying time of alkyd paints, and the time of paint drying does not depend very much on the volume concentration of this pigment. ZnO pigments had outstanding effects on drying time and physical–mechanical properties of the air-drying paints, but the best result was observed for paints containing nano–ZnO. Zinc-containing pigment systems, if composed of the nano-type, provide excellent results.     

快干聚氨酯涂料的研究

用醇酸树脂多元醇与 TDI反应制备 快干聚氨酯涂料。讨论了醇要到树脂多元醇的羟基含量、氨酯化反应的保温方式和封闭剂含量等对聚所这酯预聚 物残留单体含量及涂料性能的影响,研究了聚氨酯涂料的快干成膜机理,结果表明：该漆干燥速度快,理化性能优异,质优价廉,具有广阔的应用前景。     

Modeling, prediction, and analysis of alkyd enamel coating properties via neural computing

The use of artificial neural networks (ANNs) in the modeling and prediction of alkyd enamel coating properties, as well as in the sensitivity analysis that can be performed between the properties and the different paint components, are described. A feedforward neural network with sigmoidal activation functions was used with a conjugate gradient algorithm to recognize the complex input-output relation between the paint properties and the formula components. We restricted the study to only two properties of alkyd enamel paints: gloss and drying time. A database of five different families of alkyd enamel paints, containing the different components of the formulations as well as process information, was used in this study. The results obtained show, within the expected uncertainty tolerance, that predictive power of more than 90% for these two properties can be achieved. A sensitivity analysis was also performed using ANNs, yielding the relative importance of the different components of the formulation on the properties of the enamel coatings, which agrees with experience for gloss but gives mixed results for the drying time (apparently due to the high uncertainties in the measurement of this property).     

Safflower oil utilization in surface coatings

The unique high linoleic acid content of 78% in safflower oil makes it especially suitable to the coatings industry. The high content of linoleic acid, low amount of saturated acids, and absence of linolenic acid constitutes an oil which forms fast-drying, nonyellowing films that have an excellent through dry and low wrinkling characteristics. More safflower oil is utilized in the manufacture of alkyd resins than any other single nonedible use. The oil alcoholizes rapidly with polyols and heat-bleaches to very ligh colors in cooking the alkyd resins. These alkyds have the best combination of fast-drying and nonyellowing properties of any drying oil alkyd of equal oil content. Heat-bodies safflower oil has uniform polymer structure as shown by its viscosity reduction curves. Heat-bodied and low viscosity safflower oils are used in exterior house paints. These paints show good through dry, low wrinkling and resistance to dew flatting. Specialty uses for safflower oil include urethane resins, caulks and putties, linoleum and oil emulsion exterior house paints. Presented at the AOCS Meeting, Cincinnati, October 1965.     

Oxidative crosslinking of alkyd resins studied with mass spectrometry and NMR using model compounds

The crosslinking of alkyd resins has been studied using ethyl linoleate and methyl ricinoate as model compounds. With quantitative¹³C NMR it was established that ether- and peroxy-crosslinks were formed in roughly equal amounts. Double bonds reacted to give epoxides, endoperoxides, and β-scission into aldehydes. Using SIMS it was established that dimers through pentamers were formed having included several oxygen atoms. After reduction of peroxide (crosslinks) with stannous chloride, the higher oxygen homologues decreased. In the NMR spectrum of the reduced material, peroxide and epoxide signals completely disappeared. High resolution electrospray ionization mass spectra (ESI-MS) yielded evidence regarding the crosslink mechanism. The non-conjugated linoleic acid was found to crosslink by combination of radicals: dimers were having masses 2(M-1). The conjugated linoleic acid crosslinked by addition of radicals to the double bond and disproportionation, yielding masses 2M as well. (M = mass of ethyl linoleate or methyl ricinoate, respectively, including several oxygen atoms.) EIS-MS of oligomers after isotopic exchange enabled estimation of OH and OOH groups. Presented at the 75th Annual Meeting of the Federation of Societies for Coatings Technology, November 3–5, Atlanta, GA. General Analytical and Environmental Chemistry Dept., P.O. Box 9300, 6800 SB Arnhem, The Netherlands. P.O. Box 3, 2157 BA Sassenheim, The Netherlands.     

Weather stabilization and pigmentation of UV-curable powder coatings

A UV-curable powder coating based on an unsaturated polyester binder and a vinyl ether crosslinker has been tested for weathering resistance. Accelerated and outdoor weathering demonstrate the combined protective action of a UV absorber and a hindered amine light stabilizer (HALS). Successful coatings cure of various colors and shades from organic and inorganic pigments is also reported in this study. Curing performance mainly depends on pigment absorption and particle size. A combination of a bis-acylphosphineoxide and an α-hydroxy-acetophenone photoinitiator overcomes limitations imposed by filtering of UV radiation by the pigments and provides balanced cure. Ciba Specialty Chemicals Inc., 4002 Basel, Switzerland. DSM Resins bv. P.O. Box 615, 8000 AP Zwolle, The Netherlands.     

用于PU家俱漆中快干型醇酸树脂的研制

通过介绍快干型醇酸树脂的生产工艺和技术指标，把它同台湾生产的ＥＴＥＲＫＹＤ３１０６－Ｘ－７０醇酸树脂在干燥性能方面进行了对比，并探讨了影响其干燥性能的因素。     

Surface-fragmenting, self-polishing, tin-free antifouling coatings

Surface-fragmenting types of self-polishing tinfree resins were characterized by IR and NMR and demonstrated the successful synthesis of cupric carboxylate. According to the IR,¹H-NMR and¹³C-NMR measurements, it is clear that the unsaturated double bonds present in the resins changed into other new bonds after drying in a manner similar to alkyd resins. These resins were used as binders to prepare antifouling paints. Scanning electron microscopy (SEM), rotary tests, raft tests, and ship tests were used to investigate the self-polishing phenomena and the antifouling ability of this type of antifouling paint. The SEM photographs obtained from the paint surfaces demonstrate self-polishing phenomena. From the rotary tests, the polishing rates of paints were measured as 10μ ∼ 5.7 μ/month. The results from the raft tests show that all of the paints exhibit excellent antifouling ability and are about 80 ∼ 90% as effective as the conventional tin-containing antifouling paints. Dept. of Chemical Engineering, Tainan, Taiwan, R.O.C. #26 Yen Hai 3rd Rd., Kaohsiung, Taiwan, R.O.C.     

Drying activity of oxovanadium(IV) 2-ethylhexanoate in solvent-borne alkyd paints

Oxovanadium(IV) 2-ethylhexanoate was established as a new primary drier for alkyd-based paints. A series of experiments has demonstrated an excellent drying activity toward solvent-borne alkyd resins of different oil length at considerably lower metal concentration than optimal for commercial cobalt(II) 2-ethylhexanoate. The behavior in real paint was simulated on formulations bearing inhibitor of autooxidation. The detailed studies of the drying process have shown that the relatively slow initial step of autooxidation reaction, when compared with cobalt compounds, is compensated for by the absence of the induction times. Furthermore, the active oxovanadium(IV) species are not consumed during the drying processes as evidenced by EPR spectroscopic measurements.     

Preparation and evaluation of linseed oil based alkyd paints

Alkyd resins are produced with reaction of oil or fatty oil, polyol and polyacid. Alkyd resins are commonly used in coating and paint industry due to ease of application in changing environmental conditions. Linseed oil based paints executed all requirements of technical properties, drying time, storage properties, simplicity in maintenance, appearance, economy, etc. In this study, linseed oil based alkyd resins having different oil contents were synthesized     

Review on the durability of exterior wood coatings with reduced VOC-content

The main factors that contribute to the durability of exterior wood coatings are discussed with special emphasis on the recent developments to reduce the volatile organic compound (VOC) content in these types of coating like water-borne acrylic dispersions, water-borne alkyds or high solid alkyd formulations. The performance of a coating during outdoor weathering is determined by: photochemical degradation (only for paints that are not opaque), moisture permeability in relation to wood-moisture content and dimensional change and the microbiological degradation at the wood–coating interface. The results from various outdoor weathering studies are discussed. These studies show fairly consistent results with respect to the influence of coating type or wood species. However, a sound theory about the mechanism of failure, that can related to basic properties of the coating or the binder, has not yet been established.     

Performance of finishes on wood that is chemically modified by acetylation

Swelling and shrinkage of wood has a major effect on the performance of coatings applied to its surface. Altering the molecular structure of wood by a reaction with acetic anhydride is known to improve the dimensional stability of wood considerably. Such acetylation of wood was shown to have no effect on the drying characteristics and adhesion of applied coatings. Weathering performance of coatings was improved considerably. A color stabilizing effect was achieved with acetylated Scots pine with and without a clearcoating. Wildekamp 1C, P.O. Box 497, NL-6700 AL, Wageningen, The Netherlands. Laboratorium voor Houttechnologie, Coupure Links 653, B-9000 Gent, Belgium.     

Stabilization of aluminium pigments in water-borne systems by paint resins

Conclusions  Certain paint resins were able to inhibit the evolution of hydrogen of aluminium pigments in aqueous media at pH 10; especially drying alkyd resins showed excellent results. By contrast the two oil-free saturated polyesters examined were only very poor corrosion inhibitors at pH 10. At a pH value of 8 all polyesters, alkyd resins, epoxy esters, phenolic resins, polyurethane and acrylic resins showed an almost complete inhibition of hydrogen evolution; the two polyesters were again (relatively) worst corrosion inhibitors at pH 8. It can be supposed that the correct choice of paint resins may lead to the formulation of non-gassing water-borne metallic paints with unstabilized aluminium pigments.     

Improving Jatropha curcas Linnaeus oil alkyd drying properties

The Jatropha curcas Linnaeus (JCL) oil was extracted, refined and modified through epoxidation, hydroxylation and dehydration steps in order to increase the degree of unsaturation in the oil alkyl chain. The modified oil was subsequently used for alkyd resin preparation (50% oil formulation) using a two-stage alcoholysis-polyesterification method. Drying performances of white gloss paints formulated from the desaturated oil alkyd, considering a pigment-volume concentration of 20.67% gave improved results. Blending of the improved 50% JCL oil alkyd with acrylic further enhanced the drying properties and compare well with commercial standards. White gloss paint formulated from the improved JCL alkyd–acrylic blends (1:3) dried hard within 2 h at an outdoor temperature of 37 °C ± 2.     

Studies on the preparation of Parinari polyandra benth seed oil alkyd resins

Parinari polyandra Benth seed oil was utilized in the preparation of four sets of alkyd resin (35%, 50%, 60%, and 75% oil formulations) using a two‐stage alcoholysis‐polyesterification method. The rate of polyesterification was depended on the amount of oil used during synthesis. The properties of the alkyds (drying times, film characteristics, water and acid resistances, and solubility) were evaluated using relevant standards. Inclusion of cobalt naphthenate drier in the alkyds and their exposure to outdoor temperature improved the drying properties. White gloss paints formulated from the alkyds, considering a pigment‐volume concentration of 20.67% in the gloss paint formulation compare well with commercial standard. FTIR and ¹H‐NMR analysis confirm the alkyd (glycerol‐phthalate) structure. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Alkyd resins: From down and out to alive and kicking

Alkyd resins have been introduced in the 1930s as binders for paints. Their compatibility with many polymers and the extremely wide formulating latitude made them suitable for the production of a very broad range of coating materials. This includes do-it-yourself paints and varnishes for wood and metal, road marking paints, anticorrosive paints, nitrocellulose lacquers, two-component isocyanate curing coatings, acid curing coatings, stoving enamels, etc. Except for phthalic anhydride, being of petrochemical origin, the other raw materials used in the synthesis of the alkyds are from biologically renewable sources. This, combined with their biological degradability, makes them very interesting binders from an ecological point of view. Solvents which are used to reduce and adjust the paint viscosity are the only concern with respect to the ecological aspects of the alkyd paints. In recent years, however, we witness quite an activity in designing alkyd emulsions and high solids alkyds which can serve as binders for environmentally friendly coatings.