Study of UV-curable coatings for optical fibers

Three kinds of UV-curable prepolymers, urethane acrylate (UA), polysilicone acrylate (SA), and epoxy acrylate (EA) were prepared. These prepolymers were mixed in different proportions to modify the properties of an optical fiber coating. The relationships of component-property and structure-property of the mixture coatings were studied. When the proportion was SA:UA:EA=5:4:3, it was used for a single coating, however, the proportion SA:UA:EA=6:5:2 was used for a primary buffer coating. These mixture coatings were applied to optical fibers. No. 30 Guan Shan Road, Wuhan 430074, P.R. China.     

Properties of UV-curable polyurethane acrylates for primary optical fiber coating

Studies have been made on the effects of the chemical structure of reactive urethane acrylate prepolymers and diluents (reactive monomers) and overall composition of the prepolymer/diluent on the properties of the UV-curable polyurethane acrylates for primary optical fiber coating. We prepared several urethane acrylate prepolymers from two different isocyanates, 4,4′-dicyclohexylmethane diisocyanate (HMDI) or isophorone diisocyanate (IPDI), and two different polyols, polybutadiene diol (PBD) or polypropylene oxide diol (PPG), and 2-hydroxyethyl acrylate (HEA) with dibutyl tin dilaurate as a photoinitiator. UV-curable coating materials were formulated from the prepolymers and 2,2-dimethyl 2-phenyl acetophenone as a photoinitiator with one of four different diluents such as 1-vinyl 2-pyrrolidone (VP), lauryl methacrylate (LMA), acrylic acid 2-ethyl hexyl ester (AEHE), and acrylic acid n-butyl ester (ABE). It was found that AEHE is the desirable diluent in the formulation of the primary fiber-coating material. The desirable composition of PBD, when mixed PBD/PPG diols are used, should be about 50 wt % for optimum formulation. Most of the urethane acrylate prepolymers prepared in this study could be applied in the formulation of primary optical fiber coating and exhibited good properties of buffer functions, including low glass transition temperature, low modulus even at low temperature, say, below ?40°C, high refractive index, and low viscosity. © 1992 John Wiley & Sons, Inc.     

Preparation of UV curable emulsions using PEG-modified urethane acrylates and their coating properties III: Effects of epoxy acrylate

Water-dispersible UV-curable urethane acrylate emulsions were prepared with polyethylene glycol (PEG)-modified urethane acrylates (PMUA), containing terminal hydrophilic polyoxyethylene chains. To improve physical properties of PMUA, epoxy acrylate (EA) having high thermal stability and hardness, was mixed with five kinds of PMUA containing different chain lengths of polyoxyethylene (POE). For PMUA/EA mixtures, the composition ratio of EA to PMUA and the chain length of POE greatly influenced the size of droplets of emulsions and the physical properties of their cured films. At higher EA to PMUA ratio, the physical properties decreased, which was due to phase separation between EA and PMUA. Phase separation was confirmed by scanning electron microscopy. Received: 13 September 1996/Revised: 27 November 1996/2 December 1996     

Characterization of UV curable hybrid hard coating materials prepared by sol-gel method

Using sol-gel method, UV-curable urethane acrylate resin system was hybridized with inorganic silicate network to produce hybrid coating materials with high anti-abrasive property. In preparation of acrylate/SiO₂ hybrid materials, various acrylic reactants with multi-functional groups in addition to urethane acrylate oligomer as the main network former were employed to obtain more densified organic network structure with a high degree of cross-linking. As a silane coupling agent, 3-methacryloxypropyl-trimethoxysilane (MPTMS) was used to promote interfacial attraction between UV-cured organic acrylate resin and inorganic silicate component in the hybrid. The addition of MPTMS offered significant effect on the improvement of phase compatibility between organic and inorganic phases, which resulted in stable and homogeneous morphology with a dispersion of nano-sized fine silica particles. The results of morphological observation, glass transition behavior, and optical transparency for the hybrid gels provided an evidence for the increased interfacial attraction between two phases. From the Taber abrasion test for the hybrid coating films, it was revealed that there existed optimal ranges of inorganic silicate precursor TEOS and silane coupling agent MPTMS contents for the preparation of UV cured acrylate/SiO₂ hybrid with high abrasion resistant property.     

Polyurethane–epoxy based azopolymers: Influence of chemical structure over photoinduced birefringence

A comparative study of the influence of the competitive reactions that can take place in epoxy–isocyanate based azo systems over optical behavior was developed.Diverse disperse red 19 (DR 19) azo urethane oligomers (PUs) were synthesized and characterized using size exclusion chromatography (SEC), Fourier transform infrared (FTIR), and UV–visible spectroscopy. Based on these urethane oligomers, epoxy-PU networks having isocyanurate and oxazolidone rings in their structures were prepared in different isocyanate/epoxy stoichiometric ratios, r = eq. NCO/eq. epoxy (0.5, 1, and 2).Photoinduced anisotropy (Δn), remnant birefringence (RB) and dichroism were measured for the resulting polymers and evaluated as function of their T_gs and chemical structures. Final materials exhibited very high values of Δn and RB being promised materials for using in optical storage information devices.     

Preparation and properties of UV-curable di-functional sulfur-containing thioacrylate and thiourethane acrylate monomers with high refractive indices

We synthesized UV-curable di-functional sulfur-containing thioacrylate and thiourethane acrylate with high refractive indices. The structures of monomers were confirmed by nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR). The formulation of UV-curable coating film was prepared by thioacrylate monomer, thiourethane acrylate monomer, α-hydroxy-α-methylpropiophenone as the photoinitiator, and bisphenol A epoxy acrylate as the oligomer. The cured coating films were investigated using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), Taber abraser tests, transmittance, and refractive index. The value of refractive index for all coating films increased after UV-curing. Transparent, photocurable coating films with high abrasion resistance were prepared. The monomers showed high refractive index. The refractive indices of synthesized monomers (thioacrylate and thiourethane acrylate monomer) are 1.623 and 1.577, respectively.     

UV-curing and thermal stability of dual curable urethane epoxy adhesives for temporary bonding in 3D multi-chip package process

Multi-chip packages (MCP) refers to a packaging configuration, connected via wirebonds to a multilayer circuit board, and protected by either a molded encapsulant or a low-cost ceramic package. As it requires high processing temperature, the adhesives for MCP need to show proper adhesion and thermal stability at high temperature. This study employed semi-interpenetrated (semi-IPN) structured polymer networks using UV-curing with acrylate terminated dual-curable urethane epoxy adhesive, a dipentaerythritol hexacrylate (DPHA), using hydroxydimethyl acetophenone as photo-initiator. UV-curing and thermal stability focused on different photo-initiator contents were investigated using photo-DSC, FTIR-ATR spectroscopy, gel content and TGA. The results show that UV-curable acrylic formulations with different content of photo-initiator affects UV-curing and thermal stability.     

紫外光固化环氧丙烯酸酯涂料的制备及耐蚀性能研究

以E-51环氧树脂和丙烯酸为原料合成出光敏性环氧丙烯酸酯低聚物,制备了不同组成的紫外光固化涂料.合成产物的红外光谱分析结果表明,光敏性碳碳双键基团被引入到环氧树脂结构中;固化后涂层的红外表征结果表明,碳碳双键C=C的特征吸收峰消失,涂层固化较完全.在无水乙醇、5%NaOH和5%H2SO4溶液中的浸泡实验以及在3.5%NaCl溶液中的电化学阻抗谱测量结果表明,涂层具有较好的耐蚀性,其耐蚀性随着涂料中环氧丙烯酸酯含量的增加,呈先提高后下降的趋势.当环氧丙烯酸酯含量为40%,二缩三丙二醇双丙烯酸酯含量为50%时,所得涂层的耐蚀性最佳.     

Preparation and characterization of sol–gel derived UV-curable organo-silica–titania hybrid coatings

In this work, UV-curable organic–inorganic hybrid coatings based on cycloaliphatic epoxyacrylate were prepared by sol–gel technique. Acid catalyzed solutions of tetraethylorthosilane (TEOS) containing Ti:acac complex were used as an inorganic precursors. UV-curable, transparent hybrid coating materials were applied on plexiglass substrates and their coating performance was investigated by the analyses of various tests such as hardness, gloss, cross-cut adhesion tests, stress–strain test and optical transmission. The mechanical measurements showed that, the tensile properties of coatings underwent an abrupt change from a brittle to a tough material when the inorganic part was incorporated into the cycloaliphatic epoxy acrylate based organic network. UV–vis transmission spectroscopy results indicated that the hybrid materials with high titanium content have good transparences. The thermal behaviour of the coatings was also evaluated. It is observed that the thermal stability of the hybrids is enhanced with incorporation of sol–gel precursor.     

Properties of UV-curable polyurethane acrylates using nonyellowing polyisocyanate for floor coating

UV-curable polyurethane acrylates for poly(vinyl chloride) (PVC) floor coating were prepared using nonyellowing polyisocyanates. The effects of the chemical structure of the polyisocyanates and hydroxyacrylates, and the compositions of the prepolymer/diluent on the properties of the UV-curable polyurethane acrylates were investigated. Several different urethane acrylate prepolymers from four different polyisocyanates, isophorone diisocyanate (IPDI) adduct, hexamethylene diisocyanate (HDI) adduct, HDI biuret, and HDI isocyanurate, and two different hydroxyacrylates, hydroxyapropyl acrylate (HPA), polycaprolactone modified hydroxyethylhexylacrylate (PCMHEA). UV-curable coating materials were formulated from the prepolymers and 1-hydroxycyclohexylphenyl ketone as a photoinitiator with polyethylene glycol diacrylate (PEGDA) as a diluent. The polyurethane acrylates prepared with HDI isocyanurate and the equimolar mixture of HPA and PCMHEA showed balanced coating properties such as tensile properties, hardness, weatherability, and good adhesion. The dynamic mechanical studies showed the properties of those polyurethane acrylates were well correlated with their glass transition temperature behaviors. It was also found that the adhesion was best as a PVC floor coating with the appropriate viscosity (below 150 P at 25°C) when 35% PEGDA as a diluent was used. © 1996 John Wiley & Sons, Inc.     

聚氨酯丙烯酸酯/环氧丙烯酸酯分散体系的制备

用水性聚氨酯丙烯酸酯改性环氧丙烯酸酯,制备了聚氨酯丙烯酸酯/环氧丙烯酸酯分散体系。随着分散体中聚氨酯丙烯酸酯浓度的增加,体系稳定性增加,当其浓度达到30%时,可制得稳定的分散体系。这种分散体系可作为一种紫外光固化水性涂料,其涂膜的耐磨性、柔韧性都比环氧丙烯酸酯涂膜增强,而硬度变化不大。     

Hyperbranched polysiloxane-modified UV-curable graphene conductive coatings: preparation and characterization

A new UV-curable hyperbranched silicone epoxy acrylate resin was synthesized, and two kinds of carbon-based components, graphite and graphene, were applied as conductive materials. An ultraviolet-curing coating was successfully synthesized with using epoxy acrylate (EA) as oligomer, butyl acrylate (BA), and hyperbranched polysiloxane (HPSi) as monomers, benzoin dimethyl ether (DMPA), and benzophenone (BP) as photo-initiators, triethanolamine (TEA) as photo-activator, and other auxiliaries. In this work, the UV-curing efficiency and cured performance, together with the effect of different conductive fillers and the amount of conductive filler on the integrated performance of the composites, are investigated. The results show that as the HPSi content increases, the curing time is shortened. At the addition amount of 7.5%, it reaches the best conductivity, and at the addition amount of 10%, the corrosion resistance after curing is the best. However, the maximum tensile strength of 10.4% is obtained at 0.75 graphene. The FE-SEM micrographs of the UV-curable conductive coating show that with increasing incorporation of graphene into the substrate, the fractured surface of a rough surface changes to smooth one. Thermal properties of the films investigated using TGA curves indicate that graphene-doped conductive adhesive film (315.1 °C) possesses much higher heat resistance than that of graphite-doped conductive adhesive film.     

Preparation and characterization of UV-curable urethane acrylate oligomers modified with cycloaliphatic epoxide resin

The UV-curable urethane acrylate oligomers modified with cycloaliphatic epoxide resin, including polyether-modified cycloaliphatic polyurethane acrylate (CE-MP-UA) and oleic acid-modified cycloaliphatic polyurethane acrylate (CE-OA-UA), have successfully been synthesized and characterized by ¹HNMR and FTIR. The kinetics of the synthesis processes are studied in this paper. The effects of the molecular structure of the oligomers on the properties of cured film, including pencil hardness, impact resistance, adhesion and boiling water resistance, are discussed in detail. The experimental results indicate that the films formed by CE-OA-MP oligomers show good comprehensive performance, especially good adhesion and boiling water resistance due to the numerous hydroxyl groups, flexible segment and alicyclic structure of the oligomers. The results reveal that the alicyclic structure in the oligomer molecular make-up can effectively improve the adhesion of UV-curable coatings.     

新型UV固化P／Si协同阻燃EA涂层的制备与性能研究

为了提高uv固化环氧丙烯酸酯（EA）涂层的阻燃性能,并保持其良好的力学及光学性能,将丙烯酸羟乙酯（HEA）分别与KH-5707LPzOs反应合成新型含Si／P功能单体,并将其掺杂于EA中,制备了uV固化新型含P／Si协同阻燃EA透明涂层。利用红外光谱仪、紫外／可见光谱仪、热重及涂层力学测试仪等研究了涂层的性能。     

Surface protection of poly(vinyl chloride) by photografting of epoxy–acrylate coatings

UV-curable epoxy–acrylate coatings were used to protect poly(vinyl chloride) against superficial degradation. With α-hydroxy–acetophenone photoinitiators, the crosslinking polymerization develops in the ms time scale; 50% degree conversion is reached after irradiation times of 2.5 ms in a nitrogen atmosphere and 17 ms in air. The adhesion of the coating on to the PVC substrate can be greatly improved by inducing a photochemical grafting process. The best results are obtained by incorporating the photoinitiator into the top layer of the PVC sheet. Highly crosslinked epoxy–acrylate coatings are very stable toward UV radiations and chemical agents like organic solvents and strong acids. By their light-screening effect they provide an excellent protection against photodegradation for light-sensitive polymeric materials.     

紫外光固化聚氨酯丙烯酸酯研究进展

综述丁紫外光（UV）固化聚氨酯丙烯酸酯的研究进展,主要包括：UV固化的聚氨酯丙烯酸酯预聚物;光固化有机／无机复合材料;水性UV固化聚氨酯丙烯酸酯和UV固化超支化聚氨酯丙烯酸酯。     

High-performance waterborne UV-curable polyurethane dispersion based on thiol–acrylate/thiol–epoxy hybrid networks

Synthesis, characterization, and film performance of waterborne thiol–acrylate/thiol–epoxy hybrid coatings are highlighted in this article. A dimer acid-modified epoxy (DME) polyol, containing both hydroxyl and epoxy functional groups, was prepared by reacting epoxy resin (EEW = 190 g/equi) with dimer fatty acid at 2:1 molar ratio. Further, a base UV-curable polyurethane acrylate dispersion (UV-PUD), with a pendant epoxy functional group, was prepared by reacting polyol (DME), isophorone diisocyanate, and dimethylol propionic acid and end-capped with hydroxyethyl methacrylate with subsequent dispersion in water. Prepared intermediates were characterized for the parameters relevant to the study by physical, spectroscopic, and chemical methods. UV-curable thiol–acrylate/thiol–epoxy hybrid coatings were prepared by blending UV-PUD with trimethylolpropane tris(3-mercaptopropionate) (TMPMP) at four different thiol ratios (0, 0.3, 0.6, and 1.0) with respect to acrylate/epoxy groups. Cured films of the hybrid coating were identified by FTIR spectroscopy. The impact of thiol ratio on film performance was evaluated in terms of mechanical, chemical, thermal, and coating properties. The gel content measurements confirm that the addition of TMPMP increased the double bond conversion along with the epoxy group. Evaluation of cured samples shows the significant improvement in storage modulus, glass transition temperature, tensile strength, and hardness with increase in thiol ratio. The cured films possessed excellent water and acid resistance (<4%) even after 28 days of immersion. Moreover, the notable improvement was alkali resistance of cured films, i.e., as thiol ratio was increased from 0 to 1, weight loss in alkaline environment deceased from 49.5 to 4.5% after 28 days. Better properties of the thiol–acrylate/thiol–epoxy hybrid films will allow it as a potential application in low-volatile high-performance coatings.     

UV混杂固化树脂的合成及应用研究

对光敏环氧树脂单丙烯酸酯的合成方法进行了研究,讨论了催化剂、反应温度等因素对反应及产物性能的影响。同时将产物用于UV固化油墨配方,性能理想。     

Low VOC, low viscosity UV cationic radiation-cured ink-jet ink system

Ink-jet inks need to be very low in viscosity to transport the ink through the jet nozzle as well as for drop formation and integrity. The objective of this project was to demonstrate UV-cured systems for ink-jet inks and coatings with zero volatile organic compounds and very low viscosity. Cycloaliphatic epoxy systems were selected as binders of choice for this project due to their low viscosity and ability to be cured using UV-cationic photoinitiators. UV-curable coatings and inks with zero VOC and less than 10 cPs viscosities were formulated using exempt solvent acetone and vinyl cyclohexene diepoxide. UV-curable inks with up to 10% black dye were formulated. Rapid cure was achieved through the use of aryl sulfonium salts of hexafluorophosphoric acid. The presence of dye inhibited the reaction, but adequate cure of dyed formulations was achieved by increasing the concentration of the photoinitiator. Coatings Research Institute, 430 W. Forest Avenue, Ypsilanti, MI 48197.     

Coating performance and characteristics for UV-curable aliphatic urethane acrylate coatings containing norrish type I photoinitiators

The purpose of this study was to investigate the influence of several Norrish I (α-cleavage) type photoinitiators and UV dose on the curing behavior and coating performance of UV-curable aliphatic urethane acrylate coatings. UV-curable coatings were cured under a high-pressure mercury lamp. The curing behavior and coating performance of the UV-curable coatings that were cured using 2-hydroxy-2-methyl-1-phenyl-propan-1-one or 1-hydroxy-cyclohexyl-phenyl-ketone were superior to those of the UV-curable coatings cured using bis (2,4,6-trimethylben-zoyl)-phenylphosphine oxide or diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide, when the UV-curable coating was cured in air. Current address: Electronic Chemical Materials R&D Center, CHEIL Industries Inc.