Polyester Varnish Research Articles

The Impact Of Ultrasound-Assisted Mixing Method For Varnish And Components On The Varnish Layer’s Surface Hardness And Surface Scratch Resistance

The objective of this study was to determine effects of mechanical and ultrasound-assisted stirring methods for varnish + components mixing on the varnish layer’s surface hardness and surface scratch resistance. The study focused on polyurethane, acrylic, and polyester varnish systems, which were applied to three distinct wood types: Scots pine (Pinus sylvestris L.), Turkish beech (Fagus orientalis Lipsky), and African mahogany (Khaya ivorensis A. Chev.). The mixing processes included mechanical stirring for 3 and 5 minutes, as well as ultrasound-assisted stirring with varying power levels (80 watts and 120 watts) for 3 and 5 minutes. The results indicated that the highest surface hardness was achieved using the mechanical stirring method for Turkish beech with polyester varnish at 3 minutes of stirring (175.10), while the lowest surface hardness was observed for African mahogany with acrylic varnish and 120 watts ultrasound-assisted stirring for 5 minutes (66.80). The highest surface scratch resistance was observed in Scots pine treated with polyester varnish using mechanical stirring for 5 minutes (0.760 N), and in Turkish beech treated with acrylic varnish using 80 watts ultrasound-assisted stirring for 3 minutes (0.760 N). Overall, the findings suggested that the ultrasound-assisted mixing method generally fell short in terms of enhancing the varnish properties compared to the mechanical mixing technique.

Functionalized Unsaturated Polyester as Electrical Insulation Varnish

AbstractSilsesquioxanes (SQs) are mostly used to provide high‐temperature electrical insulation of resins. Here, SQ is used to functionalize unsaturated polyester (UPE) varnish and investigate the effect of functionalization on the thermal and electrical properties of UPE varnishes. The solvent‐free varnish incorporates a reactive diluent to decrease viscosity and a catalyst to expedite hardening, eliminating the need for solvents. Vinyl toluene (VT) and 1,4‐butanediol dimethacrylate (BDDMA) serve as hardening agents, consistent with prior research. Various characterization tests, including Fourier transform infrared, thermogravimetric analyzer, assessment of thermal conductivity coefficient, and determination of electrical volume–surface resistance, are conducted to determine the physical, thermal, chemical, and electrical properties of the synthesized SQ‐functionalized UPE (UPES) varnishes. Results indicate that the UPES–BDDMA varnish demonstrates the highest thermal decomposition temperature at 438.0 °C, while the UPES–VT varnish exhibits the highest electrical volume resistance of 2.85 × 1015 Ω cm. Volatile organic compound levels in UPE coatings range between 4.9% and 5.10% reflecting the growing demand for eco‐friendly products. It is shown in this study that the use of BDDMA and VT reactive monomers in the synthesis of SQ‐functionalized UPE resin and the properties of the resulting varnishes, especially electrical insulation and thermal stability, are improved.

Effects of Ultrasound-Assisted Varnish and Component Mixing Method on Mechanical and Physical Properties of Varnish Layer

The aim of this study was to determine the effects of mechanical and ultrasound-assisted stirring methods for varnish + components mixing on the varnish layer coating adhesion, surface roughness and glossiness. For this purpose, polyurethane, acrylic and polyester varnish systems were applied on three different wood types, namely Scots pine (Pinus sylvestris L.), Eastern beech (Fagus orientalis L.) and Mahogany (Khaya ivorensis), with mechanical and ultrasound-assisted mixing methods. In the mechanical mixing method, 3 and 5 minutes were applied, while in the ultrasonic mixing method, beside 3- and 5- minute stirring time, 80-watt, and 120-watt ultrasonic power was applied during mixing. When research results are generally evaluated, it cannot be said that ultrasound-assisted mixing method is superior to mechanical mixing method. However, the ultrasound-assisted mixing of varnish components at 80 watts for 3 minutes can be recommended.

Synthesis of low-VOC unsaturated polyester coatings for electrical insulation

Abstract The objective of this research is to develop an unsaturated polyester (UPE) varnish with low-volatile organic compounds (VOCs). Instead of using a solvent, the solvent-free varnish incorporates a reactive diluent to reduce viscosity and a catalyst to accelerate curing. To achieve this, vinyl toluene and 1,4-butanediol dimethacrylate were employed as curing agents. Sebacic acid (SA) and fumaric acid were utilized to create UPE coatings for electrical insulation. Various tests and measurements were made to evaluate the physical, thermal, and chemical structure determination, and electrical properties of the synthesized resins. Given the increasing demand for eco-friendly and low-VOC products, gas chromatography was employed to determine VOC levels. The study demonstrated that the electrical volume resistance of cross-linked coatings containing FA was 1.58 × 1015 Ω·cm, whereas coatings containing SA exhibited a measurement of 6.96 × 1011 Ω·cm. VOC levels in the UPE coatings were found to be in the range of 2.10–3.60%.

A Novel Polyester Varnish Nanocomposites for Electrical Machines with Improved Thermal and Dielectric Properties Using Functionalized TiO2 Nanoparticles.

Recently, there has been a growing interest in polymer insulating materials that incorporate nanoscale inorganic additives, as they have shown significantly improved dielectric, thermal, and mechanical properties, making them highly suitable for application in high-voltage insulating materials for electrical machines. This study aims to improve the dielectric and thermal properties of a commercial polyester varnish by incorporating different concentrations of titanium dioxide nanoparticles (TiO2) with proper surface functionalization. Permafil 9637 dipping varnish is the varnish used for this investigation, and vinyl silane is the coupling agent used in the surface functionalization of TiO2 nanoparticles. First, nanoparticles are characterized through Fourier transform infrared spectroscopy to validate the success of their surface functionalization. Then, varnish nanocomposites are characterized through field emission scanning electron microscopy to validate the dispersion and morphology of nanoparticles within the varnish matrix. Following characterization, varnish nanocomposites are evaluated for thermal and dielectric properties. Regarding thermal properties, the thermal conductivity of the prepared nanocomposites is assessed. Regarding dielectric properties, both permittivity and dielectric losses are evaluated over a wide frequency range, starting from 20 Hz up to 2 MHz. Moreover, the AC breakdown voltage is measured for varnish nanocomposites, and the obtained data are incorporated into a finite element method to obtain the dielectric breakdown strength. Finally, the physical mechanisms behind the obtained results are discussed, considering the role of nanoparticle loading and surface functionalization.

Fabrication of Nano TiO2-Polymer Encapsulated Fluorescent Pigments for Weatherability Improvement of Powder Coating

Fluorescent coatings have attracted attention due to their bright colors. However, they have fewer outdoor applications due to low stability, especially the poor weather resistance of the fluorescent pigments. In order to improve their weather resistance and maintain the excellent appearance, this study used polymer binders to coat a light shielding agent nano TiO2 on the surface of the fluorescent pigment to extend the durability. Three organic binders, polyester varnish, polyurethane varnish, and polyvinyl alcohol, were selected. Each binder was dissolved and mixed with pigments and nano TiO2 particles to make a polymer-TiO2 layer on the pigment surface. The effects of binder types and loadings were investigated and evaluated by accelerating weather test of corresponding fluorescent powder coatings. According to SEM and ash test, nano TiO2 was successfully coated on the surface of fluorescent pigments. The modified fluorescent pigment shows a strong ability to absorb ultraviolet rays, and the weather resistance of prepared coatings has been significantly improved compared with the original fluorescent powder coating. When using clear coat PE as a binder and setting the ratio of the binder to the nano TiO2 of 1:2, the UV exposure time of fluorescent powder coatings can be extended by over twelve times compared to the coatings with original pigment for the same color change. This study provides an effective approach to enhance the weather resistance of fluorescent coatings and thus expand their applications.

Some kinetic regularities of the polycondensation of glycols with carboxy-containing compounds in the synthesis of polyester resins for tin containers coating

Currently, the biggest share of paints and varnishes intended for painting internal surface of metal canning containers is accounted for by compositions containing epoxy oligomers. Despite the fact that such materials allow to obtain coatings with good adhesion to metal substrates, sufficient chemical resistance and elasticity, they have one significant drawback, which is due to the main component of epoxy resins – bisphenol A. Due to the well-known negative effects of bisphenol A on human health, the use of such materials is currently limited. Promising replacement of these materials are composites based on polyester resins. However, it should be mentioned that the disadvantage of polyester varnishes intended for canning containers is the low resistance of coatings to sterilization when laying food products in containers. The main reason for such low resistance is a relatively high content of ester groups in the structure of these polymers, characterized by low water, alkali and limited acid resistance. To increase the resistance of such coatings, we proposed to introduce fragments of unsaturated monomers (capable of homopolymerization under the conditions of polyester compositions (intended for can-coating) curing) into the composition of their polymer macromolecules. These fragments should create an additional steric hindrance for diffusion to ester groups of destructive molecules of aggressive media and ensure the durability of coatings in general. Synthesis of such polyesters is a typical polycondensation process, and to accelerate it, it is advisable to use various catalytic systems.

Features of polyester resins in terms of their use for varnishing canning containers, with improved stamping resistance

Currently, the biggest share of paints and varnishes intended for painting internal surface of metal canning containers is accounted for by compositions containing epoxy oligomers. Despite the fact that such materials allow to obtain coatings with good adhesion to metal substrates, sufficient chemical resistance and elasticity, they have one significant drawback, which is due to the main component of epoxy resins – bisphenol A. Due to the well-known negative effects of bisphenol A on human health, the use of such materials is currently limited. Promising replacement are composites based on polyester resins. However, it should be mentioned that the disadvantage of polyester varnishes intended for canning containers is the low resistance of coatings to sterilization when laying food products. The main reason for such low resistance is a relatively high proportion of ester groups, characterized by low water, alkali and limited acid resistance. To increase the resistance of such coatings, we proposed to introduce fragments of unsaturated monomers (capable of homopolymerization under the conditions of polyester compositions curing) into the composition of their polymer macromolecules. These fragments should create an additional steric hindrance for diffusion to ester groups of destructive molecules of aggressive media and ensure the durability of coatings in general. Synthesis of such polyesters is a typical polycondensation process, and to accelerate it, it is advisable to use various catalytic systems.

Investigation of the effect of reactive diluent on the properties of coatings based on unsaturated polyesters

Currently, the biggest share of paints and varnishes intended for painting internal surface of metal canning containers is accounted for by compositions containing epoxy oligomers. Despite the fact that such materials allow to obtain coatings with good adhesion to metal substrates, sufficient chemical resistance and elasticity, they have one significant drawback, which is due to the main component of epoxy resins – bisphenol A. Due to the well-known negative effects of bisphenol A on human health, the use of such materials is currently limited. Promising replacement of these materials are composites based on polyester resins. However, it should be mentioned that the disadvantage of polyester varnishes intended for canning containers is the low resistance of coatings to sterilization when laying food products in containers. The main reason for such low resistance is a relatively high content of ester groups in the structure of these polymers, characterized by low water, alkali and limited acid resistance. To increase the resistance of such coatings, we proposed to introduce fragments of unsaturated monomers (capable of homopolymerization under the conditions of polyester compositions (intended for can-coating) curing) into the composition of their polymer macromolecules. These fragments should create an additional steric hindrance for diffusion to ester groups of destructive molecules of aggressive media and ensure the durability of coatings in general. Synthesis of such polyesters is a typical polycondensation process, and to accelerate it, it is advisable to use various catalytic systems.

Synthesis and Characterization of Graphene-Based Inks for Spray-Coating Applications

Conductive inks made of graphene-like materials have attracted significant attention due to their extraordinary electrical properties. In this study, three different types of graphene-like materials, namely, graphene foam (GF), graphite nanoplatelets (GNPs) and synthetic graphite (SG), are utilized to fabricate conductive inks for printable flexible electronics applications. The results show that GF exhibits the highest surface area and pore volume, while GNPs and SG display large lateral sizes, highly crystalline structures and high-quality particles. In addition, the quality of the sprayed patterns are mainly influenced by the properties of graphene-based inks. The properties of conductive inks made from various graphene-like materials, including the viscosity, contact angle and surface energy, are investigated. The viscosity and contact angle of the conductive inks increase markedly with increasing filler loadings in a polyester varnish (PV) binder. Based on the electrical conductivity of unfilled PV, the conductive ink made of GNPs exhibits a 186% improvement in electrical conductivity at 10 vol% filler loading compared to those of 40% and 10% shown by SG and GF, respectively.

The pyrolysis characteristics of wood waste containing different types of varnishes

The wood industry produces large amounts of wood waste. This waste usually contains a number of nonwood materials, such as paints or varnishes. In this study, the pyrolysis characteristics of wood waste containing synthetic, polyurethane, and polyester varnishes were investigated for conversion into renewable liquid fuels. The elemental analysis and higher heating values of the bio- oils were determined. The chemical compounds present in the bio-oils obtained at an optimum temperature were identified by gas chromatography/mass spectroscopy analysis. The product yields and compositions were affected by the types of varnishes. The maximum bio-oil yield of 46.7% was obtained from pyrolysis of waste wood containing polyester varnish at a final pyrolysis temperature of 500 °C. The bio-oil produced from wood waste containing varnishes was composed mainly of phenols, aldehydes, acids, ketones, alcohols, benzenes, and N-containing compounds. The phenols accounted for the largest amount of compounds in the bio-oils. Therefore, the bio-oil produced from varnished wood waste could be a potential substitute for biofuels and green chemicals.

Traditional Varnishes and Acoustical Properties of Wooden Soundboards

Background: The impact of three different coating formulations, used traditionally in Iranian musical instrument industry, on acoustical properties of wooden soundboard was investigated. Methods: Shellac, Opaque Polyester Varnish (OPV) and Sandrous powder solution (50 and 5% solutions in Ethanol), were applied on pine wood and then the samples were tested using forced vibration technique. The measured acoustical parameters were specific modulus of elasticity, acoustic coefficient and acoustical converting efficiency. Results: The results indicated that, shellac lacquer caused the least negative impact on the acoustical properties of wood. Conclusion: To find better lacquers to improve the acoustical qualities of wood it should be considered that this new lacquer must be lighter in densities, exhibit higher modulus of elasticity and/or lower internal friction compare to raw unpolished wood.

Enhanced thermal resistance of nanocomposite enameled wire prepared from surface modified silica nanoparticle

Enameled wire is composed of conductive core surrounded by insulating layer. Nanocomposite enameled wires where inorganic nanoparticles are dispersed in the insulation layer have been known to exhibit higher breakdown voltage and partial discharge resistance. Dispersion of the nanoparticles is critical for fabricating nanocomposite enameled wire because nanoparticles easily aggregate in the varnish or polymer matrix during the coating processing. In this study silica nanoparticles were surface-modified with silanes using sonochemical method. The surface modified nanoparticle was well dispersed in polyester varnish, which was observed by means of optical transparency and viscosity measurement. After curing, it was found that dispersion of the nanoparticles was also well maintained, which was confirmed by SEM and DSC analyses. Consecutively we found that thermal resistance as well as dielectric breakdown strength of the nanocomposite enameled wire was enhanced by dispersing the surface modified silica nanoparticles in the insulating polymer matrix.

Analyses of the surfaces of concrete by Raman and FT‐IR spectroscopies: comparative study of hardened samples after demoulding and after organic post‐treatment

AbstractConcrete surfaces were studied by two spectroscopic techniques, FT‐IR (in ATR mode) and Raman, to establish a nondestructive method to analyze the distribution of hydrated and organic phases. The surface composition of ordinary clinker, polished concrete, concrete after demoulding, and coated concrete as used in building construction was studied. The clinker's mineral phases and the polished concrete were first analyzed by Raman spectroscopy to determine a spectrum database of the specific phases located on the surface of the concrete. Then, both spectroscopic techniques were used to analyze, directly, the surface of hardened concrete after demoulding. No impact of roughness or porosity was highlighted using Raman spectroscopy; many cementitious, or hydrated phases (alite, belite, tricalcium aluminate, ferrite, portlandite and ettringite) were clearly identified. FT‐IR in ATR mode only identified some hydrated phases: portlandite and CaOSiO2H2O (CSH), but organic residues from the demoulding oil were characterized by this technique. Furthermore, the convenience of using these techniques together was tested by analyzing the composition of concrete surfaces coated by different organic post‐treatments. FT‐IR spectroscopy was useful to identify the main organic groups at the concrete surface, whereas Raman spectroscopy was especially able to characterize the mineral/hydrated phases under a thick post‐treatment layer (constituted of polyester varnish). Due to their own specificities, these complementary techniques should be used together to easily identify all the mineral phases and organic residues/coatings on concrete surfaces. Copyright © 2010 John Wiley & Sons, Ltd.

A nano-technological product: An innovative varnish type for wooden surfaces

In this study, “nanolacke ultraviolet (UV) varnish,” developed by a Turkish dyeing and varnish company and widely accepted as a 21st century technology, has been compared to other conventional varnish types that are widely used in the industry in order to compare the dry film resistance properties of the varnishes. In this study, cellulosic, polyurethane, polyester, synthetic, and nanolacke ultraviolet varnishes were applied to beech (Fagus orientalis L.) and oak (Quercus robur L.)wood samples that had been prepared according to industry standards. Then, specular gloss, pencil hardness (scratch resistance) and surface resistance to cold liquids of these layers were determined according to the ASTM D 523-89, ASTM D 3363-00, and TS 3584 EN 12720 standards, respectively. The results of this study demonstrated that the nanolacke UV varnish had dry film resistance properties of gloss, scratch resistance and surface resistance to cold liquids that were superior to these same properties for the conventional varnishes. Key words: Wood, varnish, nanotechnology, coatings.

UV-shielding and catalytic characteristics of nanoscale zinc-cerium oxides

Fine particles of zinc-cerium oxides (ZCO) used as an ultraviolet filter were prepared via combustion synthesis route. The catalytic activity, UV-shielding performance, surface modification and application of ZCO in polyester varnish were discussed in detail. The experimental results indicate that the photo-catalytic activity of ZCO is much smaller than these of ZnO and TiO2; the oxidation catalytic activity of ZCO is far lower than that of CeO2; the ZCO has shown excellent ultraviolet absorption in the range of UV; addition modified ZCO (MZCO) into polyester will enhance the UV-shielding capability of polyester.

Varnishes modified with nanoparticles for use in electrical insulation

This paper presents the results of investigation of impregnating polyester varnish modified by incorporation of various nanoparticles: fumed nanosilica, nanosilica and titanium dioxide obtained via sol-gel process, zinc oxide or montmorillonite at loading 1-3 wt. %. The compositions have been formulated using various recipes and methods of preparation of nanoparticles. The processing, mechanical, electrical, barrier and thermal properties have been examined for both basic pure varnish and varnish with nanofillers. Improving of dielectric properties (electrical strength, resistance to pulse voltage) of insulating varnishes is possible by incorporation of nanoparticles. Nanofilled varnishes exhibit also the increased thermal endurance, bond strength and smaller susceptibility to water absorption.

Synthesis and Characterization of Solventless Polyester Varnish Based on Di Cyclo Penta Diene (DCPD)

Solventless polyester varnish was synthesized by polyesterification reaction of fumaric acid (FA), propylene glycol (PG) and dicyclo penta diene (DCPD) using triphenyl phenol (TPP) as accelerator. The resulting material was characterized by FT-IR and NMR spectroscopy. The electrical properties of varnish were also measured; volume resistivity was found 5.22 × 1017 Ohm-cm at room temperature, which fulfills main requirement of electrical insulating material. Solventless polyester varnish was crosslinked with styrene, vinyl toluene, and blend of both monomers, respectively in different ratios. Tensile strength of different type of the cured varnish with vinyl monomers was also determined, which was very high for vinyl toluene cured varnish. Thermal stability of the cured samples was determined by Thermogravimetric analyzer (TGA).

Effects of Concentrations of Methyl Ethyl Ketone Peroxide on Gelation Characteristics and Shrinkage of Solventless Polyester Varnish

The effects of concentrations of methyl ethyl ketone peroxide (MEKP) on the gelation characteristics and the shrinkage properties of solventless polyester varnishes were studied. Activation energies for gelation at different concentrations (0.75, 1.0, 1.5, 2.0, 2.5, 3.0 and 5.0 phr) of MEKP were 56.2, 54.3, 53.9, 51.5, 49.4, 44.0, and 41.6 kJ/mole, respectively. The mechanism of gelation and the kinetic rate equation are proposed to define the possible reasons for the variation of the above-mentioned varnish properties in the presence of the catalyst.

Development of a silicone modified unsaturated polyester varnish for rated electrical insulation application

We report on the development of a silicone modified unsaturated polyester (SUP) using a novel combination of well known principles and rigorous calculation and control of mole fraction to produce what we believe the first SUP varnish which can be used in all insulation systems including those requiring application in vacuum (solvent free, single component). Silicone modified polyesters are available but not in solvent free and unsaturated varnish form and their chemistry is different. We believe that the nature of the chemical structure generated by the manufacturing protocol is critical to the properties of the cured SUP varnish. The properties of SUP are consistently better than those of unsaturated polyesters (UP) with respect to chemical resistance as defined by ASTM tests to moisture, acids, bases, toluene, transformer oil and silicone oil. IEC comparative tracking resistance was 300 drops vs 160-240 for UPs. Results of electrical properties vs temperature tests and heat deflection temperature suggested application to high voltage electric motors and other high temperature uses. Heat aging stability of bond strength of SUP treated helical coils was tested for tensile strength (ts) (using Stecker) and for flexural strength (fs) to determine the temperature index (TI) of the varnish alone. The end point was taken to be 14 kgf (50% loss for both ts and fs). Also, motorettes insulated with materials of high temperature class were treated with SUP for TI evaluation. The TI on a motorette was sufficient (208/spl deg/C) to suggest application at 200/spl deg/C rating level (20,000 h level). The TIs of helical and Stecker coils were 194 and 193/spl deg/C, respectively. The literature values of TIs of UPs on motorettes with similar insulating materials never exceeded 180/spl deg/C. These properties are consistently better than the properties of conventional unsaturated polyester.