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.     

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 new fluidized bed coating process via photo‐initiated cationic polymerization

An ultraviolet (UV) photo‐polymerization particle coating process was developed by coupling the photo‐initiated cationic polymerization with the fluidized bed coating techniques. Unlike the conventional air‐suspension coating in the fluidized bed, the new process employs a UV curable composition instead of a solvent/water‐borne system as a coating material, which has a rapid curing rate and virtually no inhibition to oxygen and moisture. A modified fluidized bed coater equipped with a quartz window allows UV light to penetrate and to initiate the curing of photo‐sensitive polymerizable chemicals coated on the particles. A UV‐curable liquid composed of cycloaliphatic epoxide, oxetane, and triarylsulfonium cationic photo‐initiator was specifically formulated for the fluidized bed particle coating process. A systematic experimental approach including photo‐Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, and tackiness measurements has been developed to characterize the curing mechanism of the cationic UV curable formulations and to optimize the chemical compositions. The effects of the UV curable chemicals, viscosity of coating liquid, and the fluidization operating conditions on the physical properties of coated particles have been thoroughly investigated. Under optimized conditions, this novel process is very efficient as follows: particles can be coated very rapidly with ultra‐thin films of the cured chemicals, with little, if any, formation of particulate agglomeration. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Effect of chemical structure and shear force on the morphology and properties of jet printed black micropatterns using imide epoxy binders

Epoxy and epoxy acrylates with phthalimide groups on the main chain or pendent side chain were synthesized and used as binders for solvent‐free UV‐curable inks. Effects of chemical structures on the solubilities of binders in monomers, together with the influences of shear force and ink compositions on the morphology and nanoindentation properties of the microstripes were studied. PIK1 inks containing BAPSBD epoxy with phthalimide groups on the main chain showed shear‐thinning behaviors and pigment aggregation problems. Variations of the shear stress at different positions of the dispenser led to PIK1 microstripes with rough central regions and smoother edges. AMPDP acrylate with pendent phthalimide side chain afforded not only good solubility in monomers but also good thermal and mechanical properties after curing. Stripes prepared by the PIK2 ink containing AMPDP exhibited straight edge and smooth surface. Considering the solubility and compatibility in inks, together with properties of cured stripe, binders with pendent phthalimide groups are better candidate as UV‐curable ink compositions than those with main chain phthalimide groups. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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     

Fluorine‐containing photocurable hybrid coatings via anhydrous sol–gel method

In this study, fluorine‐doped photocurable hybrid coatings were prepared by combining UV‐curing technology with an anhydrous sol–gel method. First, methacryloxymethyl triethoxysilane (MEMO) was hydrolyzed via an anhydrous sol–gel process. Then MEMO was mixed with acrylic oligomers and predetermined amounts of fluoroacrylate resin. UV curable hybrid coatings were applied on corona‐treated plexiglass substrates. The addition of fluorine showed a significant impact on the properties of the coatings. As the fluorine content was increased in the formulations, flame retardancy and the contact angle values of the coatings increased. It was found that the optical transmittance of the coatings was higher than 95%. The surface morphology of the hybrid films was characterized by scanning electron microscopy (SEM). The chemical composition of the surface of the coatings was identified by energy dispersion spectrum (SEM–EDS) technique. SEM studies indicated that inorganic particles were dispersed homogenously throughout the organic matrix. J. VINYL ADDIT. TECHNOL., 21:272–277, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of sequential interpenetrating polymer networks of polyurethane acrylate and polybenzoxazine

High‐performance ultraviolet (UV) curable polyurethane acrylate (PUA) coating alloyed with thermally curable polybenzoxazine (PBA) is developed. The hybrid polymer networks of PUA and PBA‐a were prepared by sequential cure methods, i.e., UV cure of the PUA followed by thermal cure of the PBA fraction. The effects of sequential cure were investigated in terms of mechanical, thermal, and physical properties of the resulting polymer alloys. The fully cured PUA/PBA‐a alloy films showed only single glass transition temperature (T_g) suggesting high compatibility between the two polymer networks, possibly of an interpenetrating polymer network type. The storage modulus in a glassy state and T_g of PUA/PBA‐a alloys were found to substantially increase with increasing PBA‐a content. Furthermore, degradation temperature at 10% weight loss of the PUA/PBA‐a alloy films was relatively high whereas the char yield at 800°C was found to increase with a PBA‐a component. Hardness was enhanced, whereas water absorption and water vapor permeation rate of the alloy were suppressed by the incorporation of the PBA‐a into the polymer alloys. As a consequence, the properties of UV curable PUA networks can be positively tailored and enhanced by forming hybrid network with PBA‐a. POLYM. ENG. SCI., 54:1151–1161, 2014. © 2013 Society of Plastics Engineers     

Outdoor applications of UV curable clearcoats - a real alternative to thermally cured clearcoats

In addition to other technologies, i.e. high-solids, waterborne and powder coatings, UV curable coatings are also certain to play an important role in the coating industry's future, especially as a means of overcoming solvent emission limitations and energy savings. In principle, ultraviolet curable coatings can be used in all applications as long as the performance requirements are fulfilled. One of the most important requirements for a broad use of UV curable coatings in the coating industry is that coatings are stable against degradation caused by atmospheric influences. This weathering leads to a degradation of the polymeric binder. With novel photoinitiators based on bis-acylphoshinoxides (BAPO) it is possible to cure clearcoats containing a combined UV-absorber/HALS light stabilizer package. These clearcoats show both a very good curing behaviour and an improved weather-fastness over a long period of time.     

Ink and moisture sorption study in UV‐curable polyurethane acrylate

A study of the interaction of commercial black ink with a UV‐curable polyurethane acrylate (PUA) is presented. Diffusivity and solubility in PUA cured using different UV dosages, and subjected to different post‐UV curing conditions, were studied, as was the swelling produced by such sorption. Experiments were also conducted using water, to serve as a benchmark and compare with the effect of ink. The percentage ink absorption was found to decrease with higher degree of cure. In addition, through desorption measurements, ink induced swelling of PUA processed under different conditions was determined. The degree of swelling per unit solvent uptake was observed to increase with the degree of cure. PUA was determined to be more prone to moisture rather than solvent uptake. However, the coefficient of moisture expansion (CME) was found to be ～ 35% lower than the coefficient of ink expansion (CIE) for a fully cured PUA. © 2006 Wiley Periodicals, Inc. JAppl PolymSci 103: 1985–1991, 2007     

New ultraviolet‐curable formulations for bonding poly(vinyl chloride)‐coated fiberglass wire mesh for reinforcement applications

The advantages of the ultraviolet (UV)‐curing process are numerous, including a rapid cure, conservation of energy, environmental and user friendliness, and superior finish properties such as a high gloss and chemical and scuff resistance. In addition, the UV‐curing process offers flexibility suitable for sensitive substrates and complete screen stability because UV ink dries on exposure only to a UV‐energy source and not to ambient UV‐light sources such as sunlight or fluorescent shop lights. Industrial methods apply traditional heat setting to form mesh reinforcement structures from poly(vinyl chloride)‐coated fiberglass wires. The main defects of this method are the inefficiency and inconsistency of the process plus the huge consumption of power needed to generate the necessary thermal energy to bond the wire mesh. The heating process also causes quicker degradation of the wire and shortens the lifetime of the product. The purpose of this current innovative work is to replace this defective heat‐setting method with the more efficient and very advantageous method of applying UV‐curable coatings for this task. The obtained results are prospective for this endeavor, covering the issues of energy conservation, the economy of the process, and the improved mechanical properties of the finished product. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of UV‐curable difunctional silane monomer based on 3‐methacryloxy propyl trimethoxysilane (3‐MPTS) and its UV‐curing characteristics and thermal stability

In the present investigation, silicon containing UV‐curable difunctional monomer was synthesized by reacting 3‐methacryloxy propyl trimethoxysilane (3‐MPTS) with acrylic acid using anhydrous ether as a solvent under inert atmosphere. The synthesized acryloxymethacryloxy silane monomer was characterized by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. The silane monomer along with 4 wt % photoinitiator (Darocure 1173) was cured under UV‐light for different exposure time. The curing characteristic of the monomer was investigated using FTIR spectroscopy. The conversion of the double bond due to curing has been evaluated from the peak intensity of the C?C double bond (at 1636 cm^?1) in the FTIR spectrum considering the peak intensity at 1720 cm^?1 due to C?O as internal standard. The maximum double bond conversion is observed to be 72%. The optimum cure time for the silane monomer has been estimated to be 7.8 sec. The UV‐cured sample decomposes at 440°C. The char residue is 35% at 700°C. The synthesized UV‐curable silane monomer may be useful for UV‐coating formulations, for fabrication of 3D‐objects by lithographic technique and as a precursor for organic–inorganic hybrid materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Ultraviolet‐curing behavior and mechanical properties of a polyester acrylate resin

Ultraviolet (UV) curing technology has been widely used in many applications because it has several distinct advantages compared to solvent‐based processes or thermal‐curing technology. The effects of photoinitiator types and their contents as well as reactive diluent types and their contents on the UV‐curing behavior and mechanical properties of a UV‐curable polyester acrylate resin were investigated in this study. Three photoinitiators, Irgacure 184, Darocur 1173, and benzophenone, were used in this study. Hexanediol diacrylate, tripropylene glycol diacrylate, and trimethylol propane triacrylate were used as reactive diluents to modify the properties of the acrylate resin. The change of chemical structure during UV curing was monitored by FTIR. A universal testing machine was used to measure the tensile properties of various UV‐cured acrylate films of different compositions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3921–3928, 2004     

Ultraviolet radiation curable epoxy resin encapsulant for light emitting diodes

Light‐emitting diodes are currently encapsulated by thermally curable epoxy resins. Thermal curing systems require long curing cycles at high temperatures. Further, because of viscoelastic behavior of the resin, the resin tends to “creep” along the connecting wires (Weisenberg effect), which causes solderability problem. The cured resin should be removed manually, which is time consuming and labor intensive. These problems are solved by the ultraviolet radiation curable systems. UV curing is an ultrafast reaction and takes place at room temperature. No creep behavior occurs due to the rapidity of the curing. The UV curing technique can result in higher productivity and energy saving than the thermal process. This article presents results on the development of UV curable formulations based on cycloaliphatic diepoxide, diglycidyl ether of bisphenol A, and epoxidized novolac induced by cationic photoinitiators. “Mixture experimental design” was employed to arrive at the optimum composition, which meets the stringent demands of performance characteristics and durability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1048–1056, 2006     

Preparation of multifunctional thiol‐ and acrylate‐terminated polyurethane: A comparative study on their properties in UV curable coatings

The multifunctional thiol‐ and acrylate‐terminated polyurethane (PU) has been successfully prepared for using as the main resin in the UV curable coatings. The structure and molecule weight of prepared PUs were analyzed by fourier transformed infrared spectroscopy (FTIR) and gel permeation chromatography, respectively. The results showed that the different terminal multifunctional groups have been grafted onto the PU and their difference in molecule weight was significant. Used as the main resin in coatings, the curing kinetic and percentage conversion of the different UV curing coatings system were investigated by real‐time FTIR method, and the effects of terminal functional groups and photoinitiator on the final conversion percentage and conversion rate were also compared. It is observed that the thiol‐terminated PU had higher conversion speed and final conversion percentage due to the remarkable effect of mercapto groups on reducing oxygen inhibition during UV curing process. The shrinkage, viscosity, and adhesion of UV curable coatings with thiol‐ and acrylate‐terminated PUs were also investigated and compared, and the results indicated that the former exhibited lower shrinkage and higher adhesion performances than the latter, along with the lower viscosity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40740.     

An UV‐curable epoxy acrylate oligomer with high refractive index containing fluorene: Preparation,characterization, and application

In this article, a novel UV‐curable epoxy acrylate oligomer (BPEFPGMA) with high refractive index is successfully prepared through semi‐esterification reaction of 9,9‐bis[4‐(2‐hydroxyethoxy)phenyl]fluorene and phthalic anhydride, followed by end‐caping of glycidyl methacrylate. After 15 times’ repetitions, the process and properties of this oligomer are stable and reliable. The resulting BPEFPGMA exhibited low solvent content (≤1600 ppm), low viscosity (1900–2500 mPa s at 60°C), high refractive index (1.587 ± 0.003 at 20°C), and normal M_w (2550–3536 g/mol). The coating formulations of 1.57 UV‐curable glue are mixed with BPEFPGMA as reactive oligomer. Through the technology of UV‐curing forming, the corresponding brightness enhancement films are obtained. The resulting films exhibit normal structure, excellent adhesion (5B), good scratch resistance (50 g), and good abrasion resistance (50 g). They show excellent performance, and have reached the quality standard for use in liquid crystal display industry. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42386.     

UV‐assisted three‐dimensional printing of polymer nanocomposites based on inorganic fillers

In this work, nanocomposites based on a UV‐curable polymeric resin and different inorganic fillers were developed for use in UV‐assisted three‐dimensional (UV‐3D) printing. This technology consists in the additive multilayer deposition of a UV‐curable resin for the fabrication of 3D macro structures and microstructures of arbitrary shapes. A systematic investigation on the effect of filler concentration on the rheological properties of the polymer‐based nanocomposites was performed. In particular, the rheological characterization of these nanocomposites allowed to identify the optimal printability parameters for these systems based on the shear rate of the materials at the extrusion nozzle. In addition, photocalorimetric measurements were used to assess the effect of the presence of the inorganic fillers on the thermodynamics and kinetics of the photocuring process of the resins. By direct deposition of homogeneous solvent‐free nanocomposite dispersions of different fillers in a UV‐curable polymeric resin, the effect of UV‐3D printing direction, fill density, and fill pattern on the mechanical properties of UV‐3D printed specimens was investigated by means of uniaxial tensile tests. Finally, examples of 3D macroarchitectures and microarchitectures, spanning features, and planar transparent structures directly formed upon UV‐3D printing of such nanocomposite dispersions were reproducibly obtained and demonstrated, clearly highlighting the suitability of these nanocomposite formulations for advanced UV‐3D printing applications. POLYM. COMPOS., 38:1662–1670, 2017. © 2015 Society of Plastics Engineers     

Synthesis and ultraviolet‐curing behaviors of vinyl ether functionalized polyurethane oligomers

The vinyl ether functionalized oligomer is one of the most basic components of vinyl ether functionalized materials for cationic UV‐curable coatings. In this study, three types of vinyl ether functionalized polyurethane oligomers (i.e., polyether, polyester, and polydimethylsiloxane) were synthesized with diisocyanate, diol, and hydroxyethyl vinyl ether. These oligomers were characterized by IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. The effect of the raw material ratio on the oligomer, UV‐curing behaviors, and thermal properties of these oligomers were investigated. The UV‐curing behavior was analyzed by real‐time Fourier transform infrared spectroscopy. The vinyl ether terminated polyester urethane oligomer exhibited better UV curing, with a higher final conversion and maximum UV‐curing rates. In addition, the light intensity was enhanced for oligomers with better UV‐curing properties. Research on these vinyl ether functionalized oligomers is essential to the development and applications of cationic vinyl ethers systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40501.     

Role of sand on curing of partex surface by UV radiation

A partex surface was modified by a UV‐curing system with epoxy acrylate (EB‐600). A set of formulations was prepared with oligomer and the trifunctional monomer trimethylol propane triacrylate in different combinations of percentages (1–5%) of sand to study the role of sand in various physical properties of UV‐cured thin films, as well as partex surfaces. Increased pendulum hardness (PH), gloss, adhesion, and abrasion values were obtained by the addition of sand into the partex surfaces. The best results were obtained with the formulation containing 3% sand. An enhanced PH and a decreased percentage of gel content of the UV‐cured film was observed with an increase of the sand concentration. A simulated weathering test was performed with partex surfaces cured by a formulation containing 3% sand in the base coat. The losses of the physical properties were found to be lower over the surface treated with the formulation containing sand. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2385–2392, 2002     

New UV curing systems for automotive applications

Recent developments of new UV curable resins, which meet the high demands of automotive applications (e.g. weather stability), in combination with a new lamp technology offer extremely fast drying of paints, giving complete curing within less than 2 min (in some cases even within seconds). Since the capacity of the painting/drying booth is the bottleneck in most body shops and OEM lines, this new technology offers a remarkable time saving advantage to the customer. The new technical standard is presented by a dual cure system due to the advantages of lower volume shrinkage and curing of shadow areas. The change of mar and chemical resistance depending on the amount of UV curable components in a one pack automotive clear coat is shown. The influence of both — temperature and distance — between the lamp and the painted object has been investigated by the decrease of UV curable double bonds in a given dual cure refinishing clear coat.     

New polyester acrylate resins from palm oil for wood coating application

The aim of this study is to investigate the potential use of palm oil and to prepare new UV (ultraviolet) radiation‐curable acrylated polyester prepolymers, which could be used in the wood coating industry. Thus, palm oil‐based acrylated polyester resins PEPP‐1 (from refined, bleached, and deodorized palm oil) and PEPP‐2 (from crude palm oil) were synthesized at the Advanced Oleochemical Technology Centre (AOTC) laboratory of Palm Oil Research Institute of Malaysia (PORIM). The performances of these resins with respect to their curing rate and physical‐mechanical properties of cured products under UV radiation were studied. It can be concluded that newly synthesized UV radiation‐curable polyester acrylated prepolymers (palm oil based), namely PEPP‐1 and PEPP‐2, can be used as radiation curable coating materials for wood coating applications. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2156–2163, 2001