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     

Synthesis and properties of ultraviolet/moisture dual‐curable polysiloxane acrylates

Ultraviolet (UV)/moisture dual‐curable polysiloxane acrylates (PSAs) were prepared from N,N‐bis[3‐(triethoxysilyl)propyl]amine (G402) and ethoxylated trimethylolpropane triacrylate (EB160) through Michael addition. The obtained prepolymers were characterized by ¹H‐NMR and FTIR. The rheological behavior of the prepolymers exhibited the properties of a Bingham fluid and the apparent viscosity was directly correlated with molecular weight. The photocuring kinetics of PSA were studied using photo‐DSC and all the polymerization conversions were high. With increasing content of tertiary amine in the prepolymer, the photocuring rate in air increased as well. The moisture‐curing kinetics of the prepolymers was studied using FTIR. It was found that the curing mechanism may be described as the transforming of Si O C into Si O Si structure, which was consistent with the theoretical expectation. DSC and TGA were used to characterize the glass‐transition temperatures and the thermomechanical stability of the prepolymers. Measurements of physical properties showed excellent gloss, impact strength, and high electric resistance for both UV‐ and moisture‐cured films, but poor adhesion for UV‐cured films and lower hardness for moisture‐cured films. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 846–853, 2005     

Allyl ether‐modified unsaturated polyesters for UV/air dual‐curable coatings. II: UV and air‐curing behavior

The photoinduced and peroxide‐induced polymerization behavior of dual‐curable allyl ether‐modified unsaturated polyester (AUPE) and vinyl ether (VE) used as a reactive diluent for dual‐curable coating have been studied by infrared spectroscopy (IR). For UV curing systems in N₂ atmosphere, the maleate's conversion and total conversion decrease with the increasing of allyloxy content. However, the rate and of copolymerization and conversion of VE are independent of allyloxy concentration. The copolymerization of allyl ether (AE) and vinyl ether occurs in the presence of maleate (MA) under UV irradiation. For air curing, the rate of copolymerization increases with allyloxy content. The ultimate conversion is the same irrespective of the allyloxy concentration. Because the electron‐rich double bond of allyloxy would become an electron‐deficient one through oxidation, the conversion of maleate decreases with increasing of the allyloxy content due to the enhancement of copolymerization of AE with VE. The ATR‐IR showed that different curing mechanisms occur in AUPE/VE system during air‐curing process. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2771–2776, 2004     

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.     

UV涂料用活性稀释剂研究进展

简单介绍了紫外光固化涂料的固化原理,重点综述了应用于自由基、阳离子固化体系及混杂体系中活性稀释剂的研究进展。指出开发原料来源广泛、毒性低、价格适中,拥有高转化率、高聚合速率等优良性能的稀释剂,是未来UV涂料用稀释剂的发展方向。     

紫外光固化涂料附着力促进剂的研制

为了解决紫外光固化涂料附着力差的问题,以丙烯酸羟乙酯或甲基丙烯酸羟乙酯与五氧化二磷为原料在一定条件下进行亲电加成反应制得可紫外光固化的含磷酸基团的附着力促进剂。采用酸值跟踪测试确定总反应时间为3.5h。对产品进行红外光谱分析,表明反应物中的羟基已经完全反应以及产物中磷酸基团与CC双键的形成。对比了自制产品与市售产品在不同板材上的性能,结果表明这两种产品对紫外光固化涂料与金属、玻璃、木材等极性基材都具有很好的附着促进作用,并确定了自制产品的优势。     

Synthesis of fluorinated/methacrylated epoxy based oligomers and investigation of its performance in the UV curable hybrid coatings

Organic–inorganic hybrid coatings based on fluorinated/methacrylated soybean oil and bisphenol A/F epoxy methacrylate were obtained by combining photopolymerization and sol–gel process. Hard and transparent hybrid coatings were prepared on polycarbonate panels and their physical and mechanical properties such as gel content, hardness, adhesion, gloss, contact angle as well as tensile strength were measured. Results from the mechanical measurements showed that the properties of hybrid coatings improved with the increase in fluorine and sol–gel precursor contents. Thermo gravimetric analysis results demonstrated that fluorine and silica incorporations significantly enhanced the thermal oxidative stability of the hybrid coating materials. The surface morphology was also characterized by scanning electron microscopy (SEM). SEM studies indicated that inorganic particles were dispersed homogenously throughout the organic matrix.     

光/湿双固化聚氨酯热熔胶的制备与性能研究

以多元醇、异氰酸酯、含羟基丙烯酸酯和光引发剂等为原料,制备了PET(聚酯)基材粘接用光/湿双固化PU(聚氨酯)-PUA(聚氨酯丙烯酸酯)型反应性HMA(热熔胶)。研究结果表明:该HMA中同时含有可光固化基团(C=C)和可湿固化基团(-NCO);当n(C=C)∶n(-NCO)=20∶80、w(复合光引发剂)=1.5%~2.0%和引入甲基丙烯酸羟乙酯(HEMA)时,相应HMA具有较高的初始强度和最终强度;光/湿双固化HMA的透明度高于湿固化HMA,说明UV固化是增加光/湿双固化HMA透明度的主要原因。     

Characterization and properties of UV‐curable polyurethane‐acrylate/silica hybrid materials prepared by the sol‐gel process

UV‐curable, transparent hybrid material of urethane‐acrylate resin was prepared by the sol‐gel process using 3‐(trimethoxysilyl)propylmethacrylate (TMSPM) as a coupling agent between the organic and inorganic phases. The effects of the content of acid and silica on the morphology and mechanical properties of UV‐curable polyurethane‐acrylate/silica hybrid (UA‐TMSPM)/SiO₂ materials have been studied. The results of thermogravimetric analysis for the (UA‐TMSPM)/SiO₂ hybrid materials indicated that the thermal stability of the hybrids is greatly improved. It was found that with the increase of HCl content, the interfacial interaction between organic and inorganic phases had been strengthened, as demonstrated by field emission scanning electron microscopy. Without sacrificing flexibility, the hybrid materials showed improved hardness with increasing content of acid and silica. Compared with the pure organic counterpart UA/hexanediol diacrylate (UA/HDDA) system, abrasion resistance of the hybrids improved with increasing acid content, at low silica content. Copyright © 2004 Society of Chemical Industry     

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     

Novel fluorescence method for cure monitoring of hydrosilation‐curable silicones

This study aimed to evaluate a reactive fluorescent probe, 9,10‐bis‐(phenylethynyl) anthracene (BPEA), for cure monitoring of hydrosilation‐curable silicones. The hydrosilation‐curable silicones consisted of a vinyl‐terminated polydimethylsiloxane prepolymer, a methylhydrosiloxane‐dimethylsiloxane copolymer, and an inhibitor, 1,3‐divinyltetramethyldisiloxane. The hydrosilation reaction was catalyzed with the solution of a platinum catalyst in the prepolymer. The catalyst solution also contained a trace amount of the reactive fluorescent probe. Three hydrosilation‐curable silicones, with the prepolymer of varying molar mass, were investigated. Each of the hydrosilation‐curable silicones was mixed with the catalyst solution at the mass ratio of 1 : 1 to initiate the cure. During the cure of each mixture at 22°C, the elastic modulus of the mixture and the fluorescence spectrum of the probe at the excitation wavelength of 360 nm were measured. Initially, the elastic modulus changed slowly, but then increased rapidly as a result of the increase in molar mass. The elastic modulus leveled off and reached a plateau value at the setting time. The ratio of the fluorescence intensities at 422 and 466 nm increased steadily, and then leveled off and reached a plateau value at the setting time, in agreement with the setting time determined from the change in elastic modulus. The reactive fluorescent probe, BPEA, can therefore be used for nondestructive fluorescence monitoring of hydrosilation‐curable silicones. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Novel moisture‐curable epoxy resins and their characterization

The shelf‐life stability and curability of a moisture‐curable epoxy resin system were evaluated with ketimines, which were used as moisture‐latent hardeners and were derived from different kinds of ketones as protective groups. Both the shelf‐life stability and curability of the compounds were mainly influenced by the steric hindrance of the ketimines. The theoretical results calculated by MOPAC showed good agreement with the experimental results. Methyl i‐propyl ketone and methyl t‐butyl ketone, having a narrow space (<4.2 Å) around ketimine N and a wide space (>3.7 Å) around ketimine C, were demonstrated to be the optimum ketones for the ketimines. The lap shear strength, with respect to the adhesive properties of the ketimines, was higher with a large‐volume ketone than with a small‐volume ketone as the protective group. This was due to the higher reaction conversion of the epoxide for the system. In addition, the large plasticizing effect of the large ketone volume could lead to a large relaxation of the stress generated at the bonding interface. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 91–95, 2003     

全球辐射固化材料近期市场分析（一）

辐射固化技术于20世纪60～70年代,在欧美市场上初步确立了自身的产业地位,成为全球经济体系中的一个组成部分.各种专业分工不同的企业（原材料生产供应商、化学配方产品生产供应商、装置设备制造供应商和下游客户）,共同构建了UV/EB固化产业的价值链.近年来,世界三大主要地区（北美、欧洲和亚洲）辐射固化市场以近两位数的速度在增长,尽管全球经济形势持续低迷.2012年,全球辐射固化市场配方产品的消耗量据统计大约为457000t.亚洲市场消耗量已超过欧美市场而居全球首位.辐射固化配方产品在世界三大主要地区市场中应用的重点领域虽然各不相同,然而工业涂料在全球的市场份额中仍然比例最大.本文还列出了辐射固化原材料在不同市场中的消费量与价格.     

Preparation and characterization of UV‐curable organic/inorganic hybrid composites for NIR cutoff and antistatic coatings

In this study, UV‐curable organic/inorganic hybrid composite coatings with near infrared (NIR) cutoff and antistatic properties were prepared by high‐shear mixing of two kinds of polymer matrices and coated on plastic and glass substrates by the doctor‐blade method. This study also investigated the morphology, stability, optical properties, electrical resistivity, and durability of the UV‐cured composite coats. It was found that the composite coatings were very stable under centrifugation. Moreover, the films with transmittance of above 80% in a visible light region (400–800 nm) and of ～ 40% to 50% in the NIR region (1000–1600 nm) showed low haze of 6.9%, electrical resistivity of around 2.3 × 10⁷ Ω/square. Thus, excellent adhesion, scratch, and weathering durability can be produced on polycarbonate substrate at room temperature. The experimental results reveal that UV‐curable organic/inorganic hybrid composites can be used effectively to fabricate films with NIR cutoff as well as antistatic properties, indicating a high potential for practical application in architectural, automotives, and optoelectronics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Structure‐property relations in UV‐curable urethane acrylate oligomers

Four urethane acrylate oligomers were synthesized by a reaction of an excess of isophorone diisocyanate (D) with polypropylene glycol Acclaim 4200N (P) with a subsequent reaction of nonreacted D with a hydroxy acrylate Tone M100 (A). The latter has a common name caprolactone acrylate. Oligomers were prepared by different ways of addition of P to D or D to P and at different ratio of [D]/[P]. The fifth oligomer ADA was prepared as an individual compound. Viscosities, GPC traces, T_g's of oligomers were taken alongside with other physical properties of cured oligomers. It was demonstrated that oligomers with P consist of ADPDA, ADA, and of a chain‐extended product A… P_n… A, which has two or more Ps in a molecule. Additive contributions of these three components essentially determine properties of the liquid and cured oligomers. Structure‐property relations of urethane acrylate oligomers are discussed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99:489–494, 2006     

Evaluation of new 3‐mercaptopropionate thiols for thiol‐ene photopolymerization coatings using experimental design

Three 3‐mercaptopropionate thiols, 1,6‐Hexane bis(3‐mercaptopropionate) (HD‐SH), trans‐1,4‐Cyclohexanedimethyl bis(3‐mercaptopropionate) (CHDM‐SH), and 4,4′‐Isopropylidenedicyclohexane bis(3‐mercaptopropionate) (HBPA‐SH) were formulated with 1,3,5‐triallyl‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione (TATATO) and photoinitiator. The formulations were photopolymerized via thiol‐ene photopolymerization. A ternary experimental design was employed to elucidate the influence the three thiols on the thermomechanical and coatings properties of thiol‐ene photopolymerizable materials. Tensile strength, tensile modulus, elongation‐to‐break, glass transition temperature (T_g), and crosslink density (XLD) were investigated. Coating properties including pencil hardness, pull‐off adhesion, MEK double rubs, and gloss were also investigated. Relative reaction conversion was determined by photo differential scanning calorimeter (PDSC). Thiol‐ene photopolymerizable materials containing HBPA‐SH resulted in improving tensile strength, tensile modulus, T_g, and pencil hardness but lowering of crosslink density and relative conversion. This was attributed to steric and rigidity of the double cycloaliphatic structure. The inclusion of CHDM‐SH into the systems resulted in the synergistic effect on elongation‐to‐break and pull‐off adhesion. The HD‐SH generally resulted in a diminution of thermomechanical and coating properties, but improved the crosslink density. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of hydrogen bonding interactions on the properties of ultraviolet‐curable coatings

Phenolic novolac type epoxy resin has been modified with acrylic acid (AA) and 2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid (AMPS) to form ultraviolet‐curable coatings, and integrated performances of the coatings were evaluated. It was found that the hydrogen bonding interactions among the oligomers became stronger along with the increase of AMPS content, thus the oligomer viscosity and a variety of polymer properties were affected. The polar hydrogen bond donors significantly enhanced the adhesion strength and surface wetting behavior of the coatings. Meanwhile, hydrogen bonding interactions can also reinforce the three‐dimensional structure of the film as in polymeric state, which potentially increased its glass transition temperature and mechanical properties. Results of chemical resistance showed that coatings modified with moderate amount of AMPS could be completely removed in several minutes when exposed to alkali solution or anhydrous ethanol. With these attractive features, modified films had prospective applications in temporary protective coatings. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43113.     

Preparation and properties of UV‐curable waterborne polyurethane–acrylate emulsion

Polyurethane–acrylate oligomer terminated with multiple unsaturated bonds was prepared using isophorone diisocyanate, (IPDI), methylene diphenyl diisocyanate, and polyols as monomers, using 2,2‐dimethylol propionic acid as hydrophilic chain extender, together with pentaerythritol triacrylate (PETA) as end‐capper. The UV‐curable waterborne polyurethane–acrylate (UV‐WPUA) composite emulsion was obtained by mixing the PUA oligomer with certain content of reactive diluents and then dispersing the mixture in water. The molecular structure of the polyurethane prepolymer, PUA oligomer, and UV‐cured polymer was investigated by Fourier transform infrared spectroscopy. The influence of the composition and content of the diluents and end‐capper on UV‐WPUA properties, including the emulsion stability, thermal property, water resistance, adhesion, hardness, glossiness of polymer film were studied. The results show that the WPUA emulsion has excellent stability, and the UV‐cured film features good hardness and remarkable water resistance when PETA is used as end‐capper and the end‐capping ratio of the polyurethane prepolymer is 70% and dipentaerythritol hexaacylate/dipropylene glycol diacrylate (mass ratio 1:1) is used as diluent. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45208.     

Dual‐Curing of Waterborne Urethane‐Acrylate Coatings by UV and Thermal Processing

A waterbased dual‐cure urethane‐acrylate oligomer has been synthesized by polycondensation of monomers bearing hydroxyl, isocyanate and acrylate groups. To obtain a stable aqueous dispersion, carboxylate groups were grafted on the oligomer chain and the isocyanate groups were protected by a blocking agent. After water release by a brief heating, the dry films were cured either by a short UV exposure in the presence of a photoinitiator to induce the polymerization of the acrylate double bonds, or by heating up to 150 °C to release the isocyanates and promote the polycondensation by reaction with the hydroxyl groups, but mainly by a combination of UV and thermal cure. Both processes have been followed quantitatively by infrared spectroscopy to evaluate the influence of the temperature on the reaction rate and on the cure extent. The newly developed waterbased dual‐cure coatings were found to be quite resistant to accelerated weathering because of their aliphatic structure and their high crosslink density. Their light stability was substantially improved by the addition of a hydroxyphenyltriazine UV absorber and a hindered amine radical scavenger.

Thermal curing of the dual‐cure waterborne PUA formulation at a temperature of 150 °C.