High refractive index transparent coatings obtained via UV/thermal dual-cure process

Nanostructured organic-inorganic hybrid epoxy coatings containing zirconia domains were obtained via a cationic UV/thermal dual-cure process. Uniform distribution of the in situ generated zirconia within the polymeric network on a nanometric scale (5-25 nm) was demonstrated by AFM and TEM analyses. The UV-cured films showed increase of the refractive index by increasing the zirconium tetrapropoxide content in the photocurable formulation. Coatings with a drastic cut-off in the UV spectra still maintaining transparency in the visible light were achieved. These coatings could find advanced applications as antireflection coatings, or in the optical industry.     

Hybrid organic/inorganic coatings produced using a dual-cure mechanism

A coating precursor containing both acrylate functionality and trimethoxysilane functionality was produced by reacting bisphenol-A glycerolate diacrylate with 3-isocyanatopropyltimethoxysilane. With this precursor, two different crosslinked networks can be produced. A polyacrylate network can be produced using a radiation-cure mechanism while a polysiloxane network can be produced by hydrolysis and condensation reactions involving the trimethoxysilane groups. The objective of the study was to determine the utility of this dual-cure system for generating rapid-cure coatings for corrosion protection. Coating properties were determined as a function of cure conditions. The results of the study showed that the formation of siloxane crosslinks was significantly hindered by the crosslinked network induced by the UV-curing process. Even though the overall conversion of trimethoxysilane groups to siloxane crosslinks was relatively low, coating barrier properties were significantly enhanced and coating free volume reduced. At ambient conditions, additional crosslinking occurring through siloxane bond formation increased within the first 4 days after UV-curing. Beyond this period, siloxane bond formation remained unchanged as did coating properties.     

Preparation of superhydrophilic nanosilica/polyacrylate hard coatings on plastic substrate for antifogging and frost-resistant applications

A series of photosensitive hydrophilic agents (T20) comprising Tween-20, isophorone diisocyanate, and 2-hydroxyethyl methacrylate moieties were synthesized and used in the preparation of antifog/frost resistant (AFF) hard coatings on plastic substrates. By means of a hydrophilic/hydrophobic bilayer design, the prepared coatings demonstrated not only AFF property but also water resistibility. The bottom layer is an organic–inorganic composite consisting of SiO₂ nanoparticles embedded in a polymeric network of crosslinked dipentaethritol hexaacrylate. The AFF layer incorporates T20 in the formulations and links covalently with the bottom layer through a UV-curing polymerization process. Various methods, for example, FTIR, SEM, contact angle, and steam/defrosting tests, were employed to characterize the prepared coatings. Optimally, the coatings were found to be transparent, strong (4H, pencil hardness), adhering perfectly (level 5B) to the poly(methyl methacrylate) substrate, and could be soaked in water for 24 h at 25 °C without losing hydrophilicity (contact angle ~0°) or antifogging capability. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48144.     

附着力增强型EG-BPSQ/SiO2防雾减反射涂层的设计制备

传统溶胶-凝胶法制备的二氧化硅(SiO₂)减反射涂层折射率低,减反射性能优异,但是其附着力较差,大大缩短了减反射涂层的使用寿命。通过在SiO₂溶胶中引入有机桥连聚倍半硅氧烷(EG-BPSQ),以增强SiO₂纳米颗粒彼此之间和涂层与基底之间的黏结作用,然后对所制备的复合涂层进行热处理,得到一系列附着力与减反射性能良好的防雾减反射涂层。重点研究了EG-BPSQ添加量对复合涂层微观结构、光学性能和附着力的影响规律。实验结果表明EG-BPSQ同时具有着‘’黏结‘’与‘’造孔‘’的作用,当后处理温度为150℃时,复合涂层不仅最高透过率高达98.5%,相比空白基底提高约8%,而且具有防雾效果,附着力均达到0级。     

Synthesis and properties of hyperbranched polyurethane acrylate used for UV curing coatings

The hyperbranched polyurethane acrylate (HPUA) was synthesized through the addition of hyperbranched polyurethane endcapped by hydroxyl groups (HPU-OH), with the semiadduct urethane monoacrylate (IPDI-HEA). The HPU-OH was prepared by the amidation reaction of diethanolamine with isophorone diisocyanate. The molecular structure of HPUA was characterized by FTIR and ¹H NMR analyses. The number average molecular weight and its polydispersity index were measured by GPC to be 7714 g mol⁻¹ and 1.24, respectively. The HPUA was blended with epoxy acrylate EB600 and difunctional monomer TPGDA in different ratios, and exposed to a UV lamp for photopolymerization in the presence of Runtecure 1104 as a photoinitiator at room temperature. The photopolymerization rate and final unsaturation conversion reached to the highest values with only 5 wt% HPUA addition, whereas decreased as further added. The tensile strength of UV-cured films was improved by adding less than 10 wt% HPUA without damaging the modulus, having the value of 62.56 MPa for EB₉₀HPUA₁₀ film. Besides, the elongation at break increased continuously with the addition of HPUA, reaching to 130% for EB₇₀HPUA₃₀ film. Moreover, the impact strength was greatly enhanced by the addition of HPUA, possessing nearly two times high for EB₇₀HPUA₃₀ film compared with pure EB600 film. However, the T_g decreased as HPUA was added from the DMTA measurements. According to the ratios of T_s/T_g the HPUA has good compatibility with EB600/TPGDA resin.     

Synthesis and photoinitiating behavior of benzophenone-based polymeric photoinitiators used for UV curing coatings

Three benzophenone-based type II polymeric photoinitiators, poly(2-(4-benzophenone methylene ether)-1,3-dihydroxypropane maleate)) (PBM), poly(2-(4-benzophenone methylene ether)-1,3-dihydroxypropane succinate)) (PBS), and poly(2-(4-benzophenone methylene ether)-1,3-dihydroxypropane-co-2-(phenyl-methylene-ether)-1,3-dihydroxypropane maleate)) (PBPM) used for free radical UV curing systems, were prepared through the step-growth polymerization of 4-(2,3-epoxypropyloxy) benzophenone (EBP) with maleic anhydride and succinic anhydride, as well co-polymerization with phenyl glycidyl ether and maleic anhydride, respectively. The molecular structures were characterized with ¹H NMR and FT-IR spectroscopy, and GPC analysis. For equimolar EBP and MA reaction system, the M_n led to the maximum of 6868 g/mol with the PDI of 1.22. The UV spectroscopy analysis showed that the synthesized polymeric photoinitiators possess higher UV absorption intensity in the wavelength range of 300–400 nm compared with benzophenone (BP). The photoinitiating activity was examined based on the photopolymerization of tripropyleneglycol diacrylate (TPGDA) in the presence of triethylamine as a coinitiator by using Photo-DSC method. It was found that PBM and PBS showed higher photoinitiating efficiency than BP in the photopolymerization of TPGDA. Moreover, the side BP moiety incorporated into the polymeric chain possessed higher initiating activity than end-capped BP moiety. Moreover, PBM with higher molecular weight was more efficient to photoinitiate TPGDA UV-cured. The side chromophore group distribution in the molecular chain also affected the photoinitiating activity. The highest photopolymerization rate at the peak maximum was obtained by the photoinitiation with PBM prepared with the molar feed ratio of 1.0 of EBP to MA.     

Investigation of cure advancement in dual-cure polyurethane-acrylate coatings over metal substrates

In the present study, a polyurethane acrylate (PUA) system cured via a thermal–UV (dual-cure process) was developed. The system selected for this work was a two-pack polyurethane acrylate with polyester polyol as the main component and urethane monoacrylate (UMA) as hardener. The polyester polyol was synthesized in a way to provide a final film coating containing both a suitable flexibility and high surface hardness. The thermal and photochemical curing behavior of the resin was studied via the chemorheology technique and the real-time FTIR. The Boltzmann sigmoidal model was implemented and well-fitted to the data obtained from the chemorheology measurements. The comparison between two reactive diluents, butanediol diacrylate (BDDA) and trimethylolpropane triacrylate (TMPTA) showed that BDDA reacts faster than TMPTA in the thermal curing condition. Nevertheless, the network buildup is stronger when TMPTA is used. The photopolymerization is also faster for the case of TMPTA. However, its final double bond conversion is restricted to a lower amount due to steric hindrance and higher viscosity of the system.     

全氟辛酸聚甘油酯的合成及其防雾滴性能

由全氟辛酸与聚甘油在无溶剂条件下发生酯化反应,制得全氟辛酸聚甘油酯,对反应温度、反应时间、反应原料摩尔比、催化剂种类4个主要影响因素进行了正交试验.实验结果表明,在催化剂作用下,全氟辛酸和聚甘油的摩尔比为1:1.4,205℃下反应6 h时,全氟辛酸聚甘油酯的酯化率最高达95.9%.通过红外光谱和核磁共振氢谱等表征手段对其进行了结构表征.     

Scratch resistance and oxygen barrier properties of acrylate-based hybrid coatings on polycarbonate substrate

Organic/inorganic hybrid coating materials were synthesized using acrylate end-capped polyester, 1,6-hexanediolacrylate, tetraethoxysilane (TEOS), and 3-trimethoxysilylpropylmethacrylate (TMSPM). The hybrid materials were cast onto a polycarbonate (PC) substrate and cured by UV irradiation to give a hybrid film with covalent linkage between the inorganic and the organic networks. The coating layer was characterized by FT-IR and ²⁹Si-NMR, and pencil hardness and oxygen permeation rate of coated films were investigated. The pencil hardness of all samples examined in this study was higher than 1H, whereas that of uncoated PC substrate was 6B. The hardness enhancement after coating may due to incorporation of organic acrylate resin. The oxygen permeability coefficient of the film coated with hybrid material on 3-aminopropyltriethoxysilane (APTEOS) pretreated polycarbonate substrate was 1.67×10⁻³ GPU, the lowest value in this work, whereas that of uncoated PC substrate was 8.07×10⁻³ GPU. The lower oxygen permeation rates of these films are attributed to the good adhesion between organic/inorganic hybrid coating layer and PC substrate and a dense structure induced by an increase of network density.     

Novel reactive diluents for UV/moisture dual‐curable coatings

The novel silicone‐modified polyacrylate reactive diluents for UV/moisture dual‐curable coatings were synthesized from N,N‐bis[3‐(trimethoxysilyl)propyl]amine and multifunctional acrylates such as ethoxylated trimethylolpropane triacrylate and polyethyleneglycol diacrylate through Michael addition reaction. Their structures were characterized by NMR and FTIR and their average molecular weights were determined by vapor pressure osmometry. With FTIR, it was found that the obtained diluents could be cured both by UV radiation and moisture mode. The ²⁹Si‐NMR showed that dimer was the main condensation product at the initial stage of moisture curing. The rheological behavior of the diluents investigated by rotary viscometer indicated they were very close to Newtonian fluid, and the viscosity of coatings decreased evenly with increasing concentration of reactive diluents in the coatings. In particular, they were found to be highly efficient in diluency and reactivity for UV polymerization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1500–1504, 2005     

Preparation of acrylate-based copolymer emulsion and its humidity controlling mechanism in interior wall coatings

In order to investigate the humidity controlling mechanism of an acrylate-based copolymer emulsion (ACE), the storage stable copolymer of a novel waterborne two-pack system was prepared by emulsion polymerization using main monomers and functional monomers, such as acrylic acid (AA) and diacetone acrylamide (DAAM). Influencing factors such as those affecting the coagulum and particle size of the emulsion were investigated. The obtained ACE was characterized by FT-IR spectra and dynamic light scattering (DLS) analysis, and was applied to the preparation of wall coatings with humidity controlling functions, and showed a large capacity for water absorption (274%), increasing indoor humidity and dehumidification in dry or moist environments. Based on analysis of the micro-structure of the coatings and their humidity controlling properties, a humidity controlling mechanism was suggested. The coating properties of the ACE and its film were measured, and showed excellent hardness, gloss and water resistance properties. ACE coatings (ACE-C) exhibited humidity control and excellent moisture retention due to the porous structure of the filler combined with the acrylate-based copolymer.     

Microencapsulation of triglycidyl isocyanurate by solvent evaporation method for UV and thermal dual‐cured coatings

Triglycidyl isocyanurate (TGIC), a thermal curing agent, was encapsulated with poly(methyl methacrylate) with small particle size and narrow distribution for the application in acrylic resins to prepare one‐package UV and thermal dual‐cured coatings. Investigation of the wettability and thermal properties suggests that the microcapsules have better compatibility with acrylic resins and thermal stability as compared to pure TGIC. Results of the release performance experiments indicate good storage stability at 25°C and a quick release of vast TGIC at 120°C for the microcapsules. The UV‐thermal dual‐cured coatings prepared with the microcapsules exhibit a fast, even and complete hardening at 130°C together with an excellent adhesion to the mild steel panels. The results presented here show an application potential of the microcapsules in UV and thermal dual‐cured paints. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41008.     

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。     

木器涂料用苯丙微乳液的合成

以苯乙烯、甲基丙烯酸甲酯和丙烯酸丁酯为主要单体,过硫酸盐为引发剂,通过种子乳液聚合法合成了新型木器涂料用苯丙微乳液,研究了乳化剂的用量、阴离子非离子乳化剂配比、聚合工艺、功能性单体的种类和用量、软／硬单体组成对乳液和涂膜性能的影响。     

Preparation and properties of polymer/LDH nanocomposite used for UV curing coatings

The thermal and mechanical properties of UV curing coatings consisted of urethane acrylates as an oligomer and a diacrylate monomer were reinforced by using layered double hydroxide (LDH). The LDH was organically modified by an ion-exchange process, in which the nitrate anions were replaced by long alkyl sulfate anions. With organic modification, the d-spacing of inorganic LDH layers was greatly enlarged to 2.75 from 0.78 nm, leading the LDH to be organophilic. During in situ photopolymerization process, the d-spacing of LDH layers was further enlarged to 4.29 nm, indicating the intercalation of polymer chains. For comparison, polymer/LDH nanocomposite filled with un-modified LDH was also prepared, and showed less enhancement in thermal and mechanical properties.