Preparation and evaluation of epoxy methacrylate UV‐curable coatings containing phthalazinone

Epoxy methacrylate resin (EMA) UV‐curable coatings exhibit high reactivity, low viscosity and excellent chemical resistance in environmentally friendly coatings. A novel EMA containing phthalazinone moieties for high temperature resistant UV‐curable coatings was synthesized. The formulations were cured with hexanediol diacrylate (HDDA) and trimethylol propane triacrylate (TMPTA) as reactive diluents promoted by a photoinitiator, and then interpenetrating polymer networks were generated. The mechanical, chemical and thermal properties of the clear coatings were characterized using Chinese National Standard methods (GB). EMA was used with UV radiation curing in combination with 6.7 wt% of HDDA and 13.4 wt% of TMPTA, and the properties of the cured films were as follows: pencil hardness of 5 H, 30% NaOH resistance for 30 days, 15% HCl resistance for 10 days, 3% NaCl resistance for 30 days and 5% weight loss temperature of 300.5 °C. EMA UV‐curable coatings containing phthalazinone exhibit excellent chemical and thermal stability, and could be potential candidates for UV‐curable zero volatile organic compound coatings applied in the fields of salt spray corrosion, strong radiation and high‐temperature resistance. Copyright © 2009 Society of Chemical Industry     

Preparation and performance on polycarbonate of B/F/Si‐containing hybrid coatings

A series of UV‐curable B/F/Si‐containing hybrid coatings was prepared by the anhydrous sol‐gel technique. The chemical structure of the coatings was characterized by FTIR, RTIR, and ¹HNMR techniques. The UV‐curable coatings were applied to polycarbonate substrates. The physical and mechanical properties of the UV‐cured coatings, such as pendulum hardness, pencil hardness, contact angle, gel content, MEK rubbing test values, tensile strength, abrasion resistance, and gloss, were examined. Thermal gravimetric analysis (TGA) was done. The relative flammability of the hybrid coatings was tested by the limiting oxygen index (LOI) method. Results of all analyses conducted on the free films and coatings are discussed. J. VINYL ADDIT. TECHNOL., 19:39–46, 2013. © 2013 Society of Plastics Engineers     

Allyl ether‐modified unsaturated polyesters for UV/air dual‐curable coatings. I: Synthesis and characterization of the oligomers and their cured films

Allyl ether (AE)‐modified unsaturated polyester oligomers were synthesized from polyethylene glycol (PEG), maleic anhydride (MAH), and trimethylolpropane mono allyl ether (TMPAE), and characterized by Fourier transform infrared (FTIR) spectra. The UV/air dual‐curable coatings were prepared from the oligomers using vinyl ether (VE) as a reactive diluent. FTIR spectra showed that C?C bonds in the coating composition had polymerized partially after cured by UV or air. The investigation of rheological behavior of the dual curable composition suggested that all the systems belonged to pseudoplastic fluid, and the increasing allyloxy content in oligomer resulted in a higher viscosity. Differential scanning calorimetry (DSC) analysis showed that the increasing TMPAE‐PEG molar ratio resulted in lower T_g, and all samples had the same glass transition temperature irrespective of the type of curing. The results of TGA for cured films indicated that UV‐cured film had better thermal stability than the air‐cured one. The air‐cured film showed superior pencil hardness, impact strength, and flexibility to the UV‐cured counterpart. However, the air‐cured film had poor adhesion and electric resistance properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2765–2770, 2004     

A novel UV‐curable epoxy acrylate resin containing arylene ether sulfone linkages: Preparation,characterization, and properties

UV‐curing processes are used in industrial applications because of their advantages such as high‐speed applications and solvent‐free formulations at ambient temperature. UV‐curable epoxy acrylate resins containing arylene ether sulfone linkages (EAAES) were synthesized through the condensation of bis(4‐chlorophenyl)sulphone and bisphenol‐A, followed by end‐caping of epichlorohydrin and subsequently acrylic acid. UV‐cured coatings were formulated with epoxy acrylates, reactive diluents such as pentaerythritol tri‐acrylate and pentaerythritol dia‐crylate and photoinitiator. Fourier transfer infrared, ¹H NMR, and thermal gravimetrical analysis were employed to investigate the structures and thermal properties of the EAs films. The introduction of EAAES into epoxy acrylate substantially improves its thermal properties and thermo‐oxidative stability at high temperatures. In addition, the acrylate containing arylene ether sulfone linkages can also improve pencil hardness and chemical and solvent resistance of the epoxy acrylate. The obtained UV‐curable epoxy acrylate containing arylene ether sulfone linkages is promising as oligomer for UV‐curable coatings, inks, and adhesives in some high‐tech regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41067.     

Effect of hyperbranched acrylates on UV‐curable soy‐based biorenewable coatings

Utilization of biorenewable components in UV‐curable coating formulations is both economically and environmentally beneficial, particularly when compared to their petrochemical‐based counterparts. To produce UV‐curable coatings of high biorenewable content with enhanced performance, acrylated epoxidized soybean oil (ASBO) was combined with biorenewable reactive diluent tetrahydrofufuryl acrylate, adhesion promoters, photoinitiator and hyperbranched acrylates (HBAs) as synthetic tougheners. The HBAs were found to impart high functionality and low viscosity, thus increasing crosslinking in the coating network and improving mechanical and thermal properties such as film hardness, adhesion, solvent resistance, impact resistance, tensile modulus and toughness, glass transition temperature and thermal stability. Real‐time Fourier transform infrared spectroscopy showed decreased acrylate conversion when compared with a reference formulation without HBAs, which was attributed to earlier coating network vitrification during UV irradiation. ASBO‐based coatings were also thermally annealed to allow further reaction of unreacted components in the vitrified network. As a result, coating properties were further improved. Overall, the addition of HBAs as synthetic tougheners to UV‐curable ASBO‐based biorenewable coating systems was shown to greatly improve the corresponding coating properties. Copyright © 2010 Society of Chemical Industry     

UV‐curable,oxetane‐toughened epoxy‐siloxane coatings for marine fouling‐release coating applications

BACKGROUND: UV‐curable coatings are promising candidates for environmentally friendly marine fouling‐release coatings. Cationic UV‐curable epoxy‐siloxane release coatings show good release performance but suffer from poor coating mechanical properties. A difunctional oxetane monomer, DOX, was co‐photopolymerized with an epoxy‐siloxane oligomer at loading levels from 10 to 40 wt% to obtain toughened fouling‐release coatings. RESULTS: The DOX‐toughened coatings showed enhanced cationic photopolymerization activity, solvent resistance and modulus. DOX‐toughened coatings (10 and 20 wt%) exhibited higher impact resistance. The DOX‐toughened coatings showed no leachate toxicity and the coatings were hydrophobic and non‐toxic to biofilm growth when analyzed with marine bacteria and algae. In general, 10 and 20 wt% DOX‐toughened coatings exhibited better marine bacteria and algae fouling‐release performance among the DOX‐toughened coatings. Pseudo‐barnacle shear release stress for the DOX‐toughened coatings increased with increasing DOX content. Live barnacle reattachment assay showed that 10 and 20 wt% DOX‐toughened coatings had comparable barnacle removal stress to commercial silicone reference coatings. CONCLUSIONS: DOX‐toughened (10 and 20 wt%) UV‐curable epoxy‐siloxane coatings exhibited enhanced mechanical properties and better overall marine fouling‐release performance among the toughened UV‐curable release coatings studied. Copyright © 2008 Society of Chemical Industry     

UV curable soybean‐oil hybrid systems based on thiol‐acrylate and thiol‐ene‐acrylate chemistry

In this study, epoxidized soybean oil was modified to prepare acrylated epoxidized soybean oil (AESO) and vinyl/acrylate ended soybean oil (VASO), which were blended with mercaptopropyl polyhedral oligomericsilsequioxane (POSS‐SH) to prepare UV curable thiol‐acrylate and thiol‐ene‐acrylate hybrid coatings. Photopolymerization processes of the coatings were measured and the results showed that addition of POSS‐SH obviously increased the conversion of double bond. The physical and mechanical properties of all cured samples were investigated, which indicated that the pencil hardness, tensile strength, and fracture toughness were significantly improved by POSS‐SH. Moreover, with increasing POSS‐SH content, the water contact angles of cured samples were increased, and the water resistance was greatly improved. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42095.     

Morphology and mechanical properties of dual‐curable epoxyacrylate hybrid composites

A dual‐curable epoxyacrylate (EA) oligomer with one epoxide group and one vinyl group at each end was synthesized for the application as adhesive sealant in the liquid crystal display panels. However, after UV and thermal cure, the EA resin was brittle with a poor resistance to crack initiation and propagation. Liquid rubbers with different functional end groups were thus tried as toughening agents for the EA resin. Among all the rubber‐toughened EAs, the EA‐V5A5 added with vinyl‐terminated and amino‐terminated butadiene‐acrylonitrile copolymers (VTBN and ATBN) each at 5 phr had the highest fracture toughness, tensile strength, and elongation at break but a lower initial modulus. To raise the modulus, submicron‐sized silica particles (∼170 nm) with surface vinyl functional groups were further added to the EA‐V5A5 to prepare the hybrid composites. Because of interfacial chemical bonding provided by the surface vinyl functional groups, both modulus and fracture toughness were increased by adding silica particles, without any appreciable decrease in extensibility. For the hybrid composite at 20 phr silica particles, the initial modulus, fracture toughness, and fracture energy were raised by 10.3, 100, and 267%, respectively, when compared to the neat epoxyacrylate. Owing to their strong interfacial bonding, the increase of fracture toughness was mainly due to the crack deflection and bifurcation on silica particles, in addition to the rubber particle bridging and tearing as evidenced by SEM pictures on the fracture surface. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41820.     

UV固化环氧丙烯酸酯-纳米Al2O3颗粒复合涂层的性能

制备了UV固化环氧丙烯酸酯-纳米Al2O3复合涂料. 对纳米复合涂层的硬度、附着力、耐腐蚀性及热稳定性等性能进行了表征,并考察了纳米Al2O3对涂层性能的影响规律. 结果表明,涂层硬度及附着力先随纳米Al2O3添加量增加而提高,添加量为2%时,涂层附着力达1级;添加量为3%时,涂层铅笔硬度达6H;添加量继续增大,涂层硬度及附着力均下降. 对纳米复合涂层的热重分析和电化学阻抗谱分析结果表明,加入纳米Al2O3能提高涂层的热稳定性,但加入未改性纳米Al2O3使涂层的耐腐蚀性下降.     

Epoxidized and Acrylated Epoxidized Camelina Oils for Ultraviolet‐Curable Wood Coatings

Camelina oil contains nearly 90% unsaturated fatty acids and can be modified into functional monomers and polymers for value‐added industrial applications. In this study, we synthesized epoxidized camelina oil (ECO) and acrylated epoxidized camelina oil (AECO) and evaluated their potential applications as ultraviolet (UV)‐curable clear films and wood coatings. ECO and AECO were characterized using Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. Curing kinetics, thermal, mechanical, and coating properties of the polymers were investigated. The peak curing time of ECO was 0.51 min and that of AECO was only 0.09 min under UV intensity of 50 mW cm^?2. Polymerized AECO (pAECO) exhibited higher glass transition temperature, mechanical strength (storage modulus, Young's modulus, and tensile strength), crosslink density, and gloss value compared with polymerized ECO (pECO). Both pAECO and pECO coatings showed good pencil hardness (6H) and strong adhesion to wood substrates (5B, with 0% chipping off during crosscut tape adhesion test). Compared with corresponding soybean oil polymers, pAECO and pECO had better thermal and mechanical properties, respectively, attributed to their higher monomer functionalities. ECO and AECO are promising candidates for UV‐curable coating applications, which adds value to camelina oilseed feedstock.     

Characterization of UV‐curable reactive diluent containing quaternary ammonium salts for antistatic coating

Reactive diluent with quaternary ammonium salts (RDQ) for UV‐curable antistatic coating was synthesized by reacting glycidyl methacrylate (GMA) and piperazin with dropping the methansulfonic acid. In order to compare the curing behavior of RDQ with commercial monomers, the photopolymerization of RDQ, 1,6‐hexandiol diacrylate (HDDA) and 1,6‐hexandiol dimethacrylate (HDDMA) were studied by using real‐time IR spectroscopy. Surface properties such as surface resistance, pencil hardness, and solvent resistance of the cured films containing RDQ were investigated. When used as a reactive diluent in the UV‐curable coating formulation, the RDQ imparted excellent antistatic properties to the final material. The results of an Fourier transform infrared/attenuated total reflectance (FTIR/ATR) depth profile analysis show that RDQ molecules are more concentrated near the surface within a micrometer‐thick layer, indicating that existence of the ionic components in the surface layer is responsible for antistatic property. Film cured from the formulation containing 12 wt % of RDQ showed the best mechanical properties with reasonable surface properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 132–137, 2002; DOI 10.1002/app.10273     

Synthesis of bio-based unsaturated polyester resins and their application in waterborne UV-curable coatings

In this paper, three bio-based unsaturated polyesters were synthesized from itaconic acid and different diols which could be derived from renewable resources. Their chemical structures were confirmed by FT-IR, ¹H NMR and acid value as well as hydroxyl value. Waterborne UV curable networks based on these polyesters were manufactured and their mechanical properties, thermal stability and coating properties including pencil hardness, flexibility, adhesion, water resistance and solvent resistance were investigated. Results showed that the UV-cured polyester coatings exhibited high hardness, good water resistance and solvent resistance. The coatings reported in this paper combined the merits of bio-based materials, UV-curing process and water distribution.     

Epoxy acrylate UV/PU dual‐cured wood coatings

For improving the finishing performances of complicated three‐dimensional coated wood products (e.g., furniture) with some shadow zones in the absence of ultraviolet (UV) light, resulting in incomplete curing of UV coatings, the aim of this study was to investigate the characteristics and effects of curing process on the properties of epoxy acrylate UV/PU dual‐cured resin for wood coatings when compared with traditional UV and polyurethane (PU) coatings. The epoxy acrylate oligomer was synthesized for providing a double bond of acryloyl group and a secondary hydroxyl group. The UV/PU dual‐cured coating was formulated with epoxy acrylate resin/tripropylene glycol diacrylate (TPGDA) monomer by the weight ratio of 80/20, 3% dosage of benzil dimethyl ketal as a photoinitiator, and the NCO/OH mole ratio of 1.0. The aromatic polymeric diphenylmethane diisocyanate was used as a hardener. The films of the dual‐cured coating, obtained from UV‐cured or room temperature‐cured process, showed an excellent tensile strength, elongation at break, impact resistance, and lightfastness when compared with traditional UV and PU coatings; especially, the adhesion of UV/PU dual‐cured coating by UV‐cured process was better than that of traditional UV coating. It can therefore be concluded that the epoxy acrylate oligomer‐based dual‐cured coating could readily be used for complicated wood products finishing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

High bio-based content waterborne UV-curable coatings with excellent adhesion and flexibility

A series of bio-based unsaturated polyesters was synthesized by melt polycondensation of itaconic acid with 1,4-butanediol and glycerol. Their chemical structures were confirmed by FT-IR, ¹H NMR, acid and hydroxyl values. Waterborne UV curable dispersion coatings based on these polyesters and acrylated epoxidized soybean oil (AESO) were formulated. The average particle size and their stability before curing as well as the coating properties after curing, including adhesion, flexibility, pencil hardness and solvent resistance, were investigated. Results demonstrated that the glycerol segment in the polyesters together with AESO led to the excellent coating properties in terms of highest grade of adhesion (5B), 0T flexibility, pencil hardness of 5H and excellent solvent resistance (no appearance change after 250 double rubs with ethanol and acetone). This work provided us the coating systems combining the merits of being bio-based, UV-curable and water dispersible.     

Preparation and characterization of hybrid thiol‐ene/epoxy UV–thermal dual‐cured systems

Hybrid thiol‐ene/epoxy coatings were prepared by combining thiol‐ene photo‐curable formulations with epoxy monomers, through a dual UV–thermal curing process. An increase in glass transition temperature and in storage modulus was observed for the hybrid thiol‐ene/epoxy coatings when compared with the pristine thiol‐ene UV‐cured system. Also, the bisphenol A moieties introduced into the hybrid networks during the dual‐curing process induced an increase in thermal stability of the cured materials. It has been demonstrated that the addition of epoxy monomer to the thiol‐ene photo‐curable system is a good strategy to follow in order to improve the final properties of thiol‐ene‐based coatings leading to a wide range of possible applications for the hybrid materials. Copyright © 2010 Society of Chemical Industry     

A novel mono‐methacryloyloxy terminated fluorinated macromonomer used for the modification of UV curable acrylic copolymers

A novel macromonomer containing fluorinated units (PHFBMA‐GMA) was synthesized through a two‐step procedure: firstly, hexafluoro‐butyl methacrylate (HFBMA) was polymerized in the presence of functional chain transfer agent 3‐mercaptopropionic acid (MPA) and then the carboxyl acid group terminated polymer was end‐capped with glycidyl methacrylate (GMA). Chemical structures of PHFBMA‐GMA were characterized by gel permeation chromatography, fourier transform infrared spectroscopy (FTIR), and ¹H nuclear magnetic resonance (NMR). Subsequently, PHFBMA‐GMA was employed as reactive surface additives added into UV‐cured polyacrylate to modify UV‐curable coatings. It is convenient to control the tail length of the fluorinated segments in this study by adjusting the ratio of initiator and chain transfer agent. The influence of both the concentration and the molecular weight of PHFBMA‐GMA on the surface properties of UV‐cured films was investigated. With increasing both the concentration and the molecular weight of PHFBMA‐GMA, the surface energy of the UV‐cured films decreased. X‐ray photoelectron spectroscopy was employed to characterize and quantify the surface composition and the results confirm the enrichment of fluorinate atoms on the surface. Moreover, the physical properties of UV‐cured films, such as gel content, water absorption, pencil hardness, adhesion, chemical resistance, mechanical properties, optical transmittance, and thermal properties, were also investigated in detail. The novel macromonomer was economical but effective to modify the properties of the UV‐curable coatings. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43116.     

Novel high‐solids pigmented coatings prepared from a new‐synthesized isophthalate‐based oligoester,a melamine resin,and various fillers

A new‐synthesized hydroxyl‐terminated isophthalate‐based liquid oligoester (L‐311), an hexakis(methoxymethylol)melamine resin, and various inert pigments (fillers) such as either kaolins (Al₂O₃ · 2SiO₂ · 2H₂O) of different particle sizes (1.50 and 4.80 μm) or calcium metalsilicate (CaSiO₃) were used to prepare high‐solids pigmented coatings (PA and PW series, respectively). The physical, chemical, and mechanical properties (pencil hardness, Knoop hardness, flexibility, impact resistance, adhesion, gloss, solvent, and mar resistance) of the new‐formulated pigmented coatings were correlated to the chemical species of the filler, the filler's load and particle size, the quantity of the crosslinker, and the introduction of large particle size colloidal silica into the coating. For measuring the mar resistance of the pigmented coatings, the Taber abrasion method was applied and the inverse wear index, F [=I^?1, cycles/cg (wear index l, weight loss (cg) per number of cycles)], was directly related to the mar resistance. Either when kaolins or calcium metalsilicates were used as fillers, the Knoop hardness, the impact, and mar resistance of the films were affected from the filler's load, whereas the quantity of melamine resin (crosslinker) affected the knoop hardness, the gloss, and the mar resistance. The fillers' particle size and the introduction of large particle colloidal silica affected mainly the mar resistance and the gloss, respectively. The pencil hardness of the PW‐pigmented coatings series (F‐2H) was higher than that of the PA‐series (B‐HB). The chemical composition of the inert pigment proved to be a very important parameter in the preparation of pigmented coatings with specific properties that aim to meet modern and particular demands for various end‐up uses. All the new‐formulated high‐solids (nonvolatiles by weight ～ 70%) pigmented coatings (PA and PW series) presented excellent adhesion (5B), flexibility (> 32%), methyl ethyl ketone (MEK) resistance (>200 rubs), high pencil hardness, good knoop hardness, and very good impact resistance (from 100 up to 160 in.‐lb), independently of the species of the filler (kaolins or calcium metalsilicate). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 576–590, 2002; DOI 10.1002/app.10309     

UV‐curable coatings with nano‐TiO2

Nano‐TiO₂ particles were first milled into butyl acetate or trimethylolpropane triacrylate (TMPTA) to obtain TSB and TST slurries, then embedded into epoxy acrylate to obtain UV‐curable coating. The influence of nano‐TiO₂ particles on the photopolymerization kinetics, tack free time, thermal and optical properties of UV‐curable coatings was investigated. It was found that TST‐based coating had a decreasing but TSB‐based coating had an increasing UV cured rate in comparison with the pristine epoxy acrylate. Nevertheless, the TST‐based coating occupied shorter tack free time, good thermal property and UV absorbance than their corresponding TSB‐based coating. POLYM. ENG. SCI. 46:1402–1410, 2006. © 2006 Society of Plastics Engineers.     

Stabilized dispersions of titania nanoparticles via a sol–gel process and applications in UV‐curable hybrid systems

Organic–inorganic hybrid UV‐curable coatings were synthesized through blending UV‐curable components and stabilized titania sol prepared via a sol–gel process of tetrabutyl titanate (TBT) with three different stabilizers, acetylacetone (Acac), isopropyl tri(dioctyl)pyrophosphato titanate coupling agent (TTPO) and a polymerizable organic phosphoric acid (MAP). The size and the dispersion of titania particle in the UV‐cured organic matrix were dominated by the properties of these stabilizers. A cured hybrid film with titania particle size around 20 nm was obtained when TTPO was utilized as protection agent for the sol. It is interesting that the hardness and flexibility of the photocured hybrid films were improved simultaneously, in contrast to results with neat organic UV‐curable formulations. Copyright © 2006 Society of Chemical Industry     

Effects of small molecular weight silicon‐containing acrylate on kinetics,morphologies, and properties of free‐radical/cationic hybrid UV‐cured coatings

A series of UV‐curable, silicon‐containing mixtures were prepared by adding different micro amounts of small molecular weight silicon‐containing acrylate KH570 to an interpenetrating polymer network system composed of cycloaliphatic polyurethane acrylate, trimethylolpropane triacrylate, cycloaliphatic epoxy resin, free‐radical photoinitiator Irgacure 754 and cationic photoinitiator Irgacure 250 with a weight ratio of 15 : 15 : 65 : 1 : 4. Hybrid coatings with different addition amounts of KH570 (0.2, 0.6, 1.0 wt %) were cured from the mixtures by UV‐initiated free‐radical/cationic dual curing technique. Final reactant conversions and photopolymerization rates of the hybrid UV‐cured coatings were improved with the increase of KH570 content, as evaluated by conversion profiles. The morphologies and microstructures were characterized by scanning electron micro‐scopic, atomic force micrographic, and fourier transform infrared spectrophotometer measurements. Thermal, mechanical, and surface properties of the hybrid UV‐cured coatings were investigated. The increase in KH570 content caused a decrease in mechanical properties besides the breaking elongation. Thermo‐gravimetric analysis revealed that the incorporation of silicon into cross‐linked network structure resulted in high thermal stability. The surface properties of hybrid UV‐cured coatings, such as hardness, contact angle, flexibility, and glossiness were also examined. It is found that transparent hybrid coating with the addition of 1.0 wt % KH570 exhibited a relatively higher contact angle as a direct result of a relatively higher hydrophobic surface. These researches showed that micro amounts of small molecular weight silicon‐containing acrylate could greatly influence the morphologies of liquid nitrogen quenching cross sections and properties of hybrid UV‐cured coatings and could be used to modify UV‐cured coatings for some superior properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40655.