Ultraviolet Curable Inks Research Articles

Fabrication and performance evaluation of full-inkjet-printed dielectric-barrier-discharge plasma actuators

Toward the establishment of the manufacturing process of a novel active airflow control device using atmospheric pressure discharge referred as to dielectric-barrier-discharge (DBD) plasma actuator, a full-inkjet-printed DBD plasma actuator is fabricated for the first time. Printed electronics are superior in view of low-cost process and large area printing compared to photolithography process. Electrodes and dielectric layers are formed by silver nanoparticles-based inks and ultraviolet-curable inks, respectively. Surface observation using a digital microscope reveals the significant improvement of the printing accuracy with an inkjet experimental equipment used in this study compared to that fabricated with a commercially supplied inkjet printer. Electrical and mechanical characteristics of the full-inkjet-printed DBD plasma actuator are evaluated through measurements of discharge current, light emission from surface DBD, and induced flow visualization with particle image velocimetry technique. The results obtained in this study indicate that the fabricated actuator works properly as the active airflow control device using surface DBDs. The full-inkjet-printing process allows the fabrication of a flexible DBD plasma actuator that has an arbitrary electrode shape to induce desirable flow patterns and can be installed on a complex curved surface.

Cumulative Dietary Risk Assessment of Benzophenone-Type Photoinitiators from Packaged Foodstuffs.

Photoinitiators used in ultraviolet-cured ink may migrate from food packaging materials into food products. Therefore, we conducted a dietary risk assessment of exposure to benzophenone (BP)-type photoinitiators by quantifying and reducing uncertainties associated with the risk characterization. A total of 362 food packaging samples including 180 cereals, 136 fruit and vegetable juices, and 46 milk samples were subjected to fast pesticides extraction to determine photoinitiator residues. The average daily dose (ADD) of BP was the highest in the age group of zero to three years, with a P97.5 ADD of 2.56 × 10−4 mg/kg bw/day. The ADD of 2-hydroxybenzophenone (2-OHBP) was the highest in the age group of three to six years, with a P97.5 UB ADD of 3.52 × 10−5 mg/kg bw/day. The estimated UB P97.5 ADD for each age group was below the toxicological concern threshold of 0.0015 mg/kg bw/day. The cumulative toxicity of all BPs, evaluated using the MOET value, was at an acceptable level. Although the MOET value of BPs was above the safety limit in the foodstuffs studied herein, this result may be different if Taiwan were to follow regulation guidelines for BP-type photoinitiators based on the specific migration limit for the unmeasured BP residues in other foodstuffs.

An Improved Model of Height Profile for Drop-On-Demand Print of Ultraviolet Curable Ink

Abstract This paper proposes an improved model of height profile for drop-on-demand printing of ultraviolet curable ink. Unlike previous model, the proposed model propagates volume and covered area based on height difference between adjacent drops. Height profile is then calculated from the propagated volume and area. Measurements of two-drop and three-drop patterns are used to experimentally compute model parameters. The parameters are used to predict and validate height profiles of four and more drops in a straight line. Using the same root-mean-square (RMS) error as benchmark, this model achieves 5.9% RMS height profile error on four-drop lines. This represents more than 60% reduction from graph-based model and an improvement from our previous effort.

Transparent water-based UV-curable urethane acrylate ink-jet ink

Attention has recently been paid to ink-jet printing inks to more environmentally friendly types and faster methods with lower energy consumption. The ink-jet printing industry has a preference to use ultraviolet-curable inks for packaging and labeling applications. This research reports a simple approach to prepare a water-based UV-curable ink-jet ink based on urethane acrylate to print onto the transparent flexible polyethylene terephthalate substrate. Isophorone diisocyanate, dimethylolpropionic acid, a low molecular weight polyester resin, and 2-hydroxyethyl methacrylate used to synthesize the urethane acrylate resin. Then, the prepared resin was neutralized with triethylamine and emulsified in deionized water. Fourier transformed infrared spectroscopy spectra characterized the chemical structure of synthesized resin. The gel permeation chromatography was used to determine the synthesized resin's molecular weight. The hydroxyl value, acid value, conversion percentage under UV radiation, transparency, haze, and surface tension results of the emulsified resin were measured. The physical properties of prepared ink-jet ink, such as rheology, surface tension, and dynamic light scattering, were measured. The ink-jet ink could fabricate uniform patterns by a general ink-jet printer onto the transparent polyethylene terephthalate flexible substrate. Eventually, the acceptable appearance was achieved due to the transparency and clarity of the printed polyethylene terephthalate.

Acrylates: new sources and new allergens.

Acrylates are synthetic thermoplastic resins used in a multitude of products, ranging from bone cement to artificial nails. They represent an important and increasing cause of both occupational and nonoccupational allergic contact dermatitis. Isobornyl acrylate, an acrylic monomer found within ultraviolet-cured inks, adhesives and various medical devices for diabetes, has emerged as an important sensitizer. In addition, long-lasting nail products have played a significant role in the increased prevalence of acrylate allergy. Sensitized individuals classically present with facial or eyelid dermatitis, and some patients experience associated fingertip and nail changes. This manuscript reviews these two important sources of acrylate allergy and summarizes other potential new exposures, including surgical glues and wound-care products.

A multilayer thin-film screen-printed triboelectric nanogenerator

In this study, we developed a multilayer thin-film triboelectric nanogenerator (MT-TENG) that incorporates a honeycomb-patterned spacer fabricated via screen printing by using ultraviolet curable ink. The printed spacer, a thin polymer layer, and thin metal electrodes enable the formation of a single thin-film structure. When force is applied to the thin-film TENG, the honeycomb-patterned spacer helps the polymer layer deform elastically through the opening of the pattern and contact the electrode. We implemented an MT-TENG by stacking 3 30 mm × 30 mm × 1.4 mm TENG layers electrically connected in parallel. The electrical performances of the manufactured MT-TENG with respect to the open-circuit voltage and short-circuit current were 11.45 V and 4.46 μA, respectively. The instantaneous output power density was 10.56 μW/cm3 (13.30 μW). In addition, an MT-TENG shoe insole was fabricated to harvest energy from human walking. We demonstrated that the fabricated shoe insole could light up 9 commercial green light-emitting diodes during walking to have an open-circuit voltage of about 20 V.

All-Inkjet-Printed Bottom-Gate Thin-Film Transistors Using UV Curable Dielectric for Well-Defined Source-Drain Electrodes

Technological restrictions of the inkjet printing technology for printed electronics can hinder its application potential, mainly due to the limited resolution and layer homogeneity in comparison to conventional manufacturing techniques for electronics. The manufacturing of active devices such as thin-film transistors with appropriate performance using printing technologies is still one of the current challenges towards industrial applications. This work demonstrates the application of an ultraviolet (UV) curable ink as insulating material for the gate dielectric. The advantage of the UV curable ink is its fast curing and the smooth surface enabling high resolution patterns on top of it. In this way, all-inkjet-printed organic thin-film transistors (OTFTs) were fabricated with silver electrodes, UV curable gate dielectric, and 6,13-bis(triisopropylsilylethynyl)pentacene for the active semiconductor layer. By fine tuning of processing parameters and pattern geometries, a stable channel length of about 10 μm was obtained in the bottom-gate configuration without the need of additional steps, suggesting a way to build low-cost all-inkjet-printed OTFTs with well-defined source-drain electrodes and fast UV curable dielectric without any additional steps. The inkjet-printed device is characterized by an electron mobility of 0.012 cm2 V−1 s−1 and on/off ratio of 103.

Toxic Epidermal Necrolysis Following Allergic Contact Dermatitis Caused by Occupational Exposure to Ultraviolet-cured Inks

Erythema multiforme is a relatively common skin disorder; the most common cause is herpes simplex infection, but topical sensitivities reportedly also provoke this reaction. We report here a case that progressed to toxic epidermal necrolysis due to contact with ultraviolet (UV)-cured inks. The diagnosis was confirmed by patch tests to acrylates in the UV-cured inks, histopathological studies of the lesions, and positive patch test to 1,6-hexanediol diacrylate.

Optical and Color Stability of Aged Specialty Papers and Ultraviolet Cured Ink Jet Prints

The present study deals with the optical and color stability of aged specialty papers and ultraviolet cured (UV) ink jet prints. As paper substrates, a fiber synthetic paper and two types of lignin-free papers with included security elements were used. Prints of CMYK color fields using UV Curable Inks were made using a UV ink jet printer, Océ Arizona 250® GT. Samples of papers and UV ink jet prints were artificially aged using standard techniques of accelerated aging, such as moist heat (80°C and 65% RH), dry heat (105°C) and treatment with the a xenon arc lamp (35°C CT, 50°C BST, 35% RH). Aging was performed for periods of 1, 2, 3, 6, and 12 days. In this study, optical properties of untreated and treated paper substrates such as the whiteness and yellowness index and color differences between untreated and treated UV ink jet prints were followed. The tested paper substrates behaved differently. The fiber synthetic paper was more stable than both lignin-free cellulose papers. Some color differences during accelerated aging were observed in prints. The effect depends on the particular ink and type of accelerated aging. On average, dry heat treatment and treatment with the xenon arc lamp showed greater impact on CMYK prints than moist heat treatment. The most stable among the prints was the black ink.

Occupational dermatitis to ultraviolet-cured acrylic-based inks in computer hard disc manufacturing

Objective : Ultraviolet-cured acrylates and their various components and applications are reviewed in this report. Method : A 26-year-old woman involved in silk screening computer discs with ultraviolet-cured inks developed an acute allergic contact dermatitis on her hands and forearms. Patch testing revealed a number of strong reactions to epoxy resin and many multifunctional acrylates. Results : The only one listed on the material safety data sheet to which she reacted was tripropyleneglycol diacrylate (TRPGDA). The other positive reactions likely represent cross-reactions. The positive reaction to epoxy is possibly relevant and attributable to nonhardened epoxy resin contaminant in the epoxy prepolymer. Conclusion : This case report shows a new application for ultraviolet-cured acrylate based inks in computer hard disc manufacturing.

Occupational Dermatitis to Ultraviolet-Cured Acrylic-Based Inks in Computer Hard Disc Manufacturing

Objective: Ultraviolet-cured acrylates and their various components and applications are reviewed in this report. Methods: A 26-year-old woman involved in silk screening computer discs with ultraviolet-cured inks developed an acute allergic contact dermatitis on her hands and forearms. Patch testing revealed a number of strong reactions to epoxy resin and many multifunctional acrylates. Results: The only one listed on the material safety data sheet to which she reacted was tripropyleneglycol diacrylate (TRPGDA). The other positive reactions likely represent cross-reactions. The positive reaction to epoxy is possibly relevant and attributable to nonhardened epoxy resin contaminant in the epoxy prepolymer. Conclusion: This case report shows a new application for ultraviolet-cured acrylate based inks in computer hard disc manufacturing.

Occupational Dermatitis to Ultraviolet-Cured Acrylic-Based Inks in Computer Hard Disc Manufacturing

Objective: Ultraviolet-cured acrylates and their various components and applications are reviewed in this report. Methods: A 26-year-old woman involved in silk screening computer discs with ultraviolet-cured inks developed an acute allergic contact dermatitis on her hands and forearms. Patch testing revealed a number of strong reactions to epoxy resin and many multifunctional acrylates. Results: The only one listed on the material safety data sheet to which she reacted was tripropyleneglycol diacrylate (TRPGDA). The other positive reactions likely represent cross-reactions. The positive reaction to epoxy is possibly relevant and attributable to nonhardened epoxy resin contaminant in the epoxy prepolymer. Conclusion: This case report shows a new application for ultraviolet-cured acrylate based inks in computer hard disc manufacturing.

Surface chemistry of polycarbonate film and adhesion of ultraviolet-cured inks

One of the primary uses of polycarbonate film is in screen-printing applications, with ultraviolet (UV)-cured inks becoming increasingly popular due to environmental concerns. During multicolor printing operations, regions of the polycarbonate film surface are unavoidably exposed to UV irradiation during the cure of adjacent regions. Subtle changes in the polycarbonate surface chemistry affect subsequent printing on the UV-exposed surface, primarily manifest as a decrease in the ink adhesion level. In this study, static secondary-ion-mass spectroscopy (SIMS), x-ray photoelectron spectroscopy (XPS), and contact angle measurements were used to show that the surface becomes oxidized and water wettable. The degree of photo-oxidation, nature of the photoproducts, and ink adhesion characteristics were measured as a function of the UV wavelength window. Filtering out the short wavelengths (λ<300 nm) from a medium pressure Hg lamp resulted in significantly less photo-oxidation compared to identical exposures from the unfiltered UV. The ink/polymer interfaces were also examined by transmission electron microscopy (cross section) and by peeling followed by XPS and static SIMS analysis. Based on these results, mechanisms for ink/polycarbonate interface adhesion are proposed.

ALLERGIC CONTACT DERMATITIS TO ULTRA VIOLET CURED INKS

Two employees of a factory using an automated screen printing process and ultraviolet cured inks to print onto plastic bottles developed an allergic contact dermatitis, principally on the face and periorbital areas. On patch testing a contact allergy was found to the ultraviolet cured ink UV 50-85, and its multifunctional acrylic monomer component, tripropylene glycol diacrylate.

Contact dermatitis in printing tradesmen.

During a 2-year period in Toronto, Canada, 21 printing tradesmen with contact dermatitis were evaluated. 67% had allergic contact dermatitis; 29% due to ultraviolet-cured ink components. Irritant contact dermatitis accounted for 37% of the cases. The prognosis in printing tradesmen with contact dermatitis is guarded, except for those with allergic contact dermatitis due to UV-cured components, as the tradesmen who were sensitized to other contactants eventually left the trade. Offset lithography was associated with the problem in 18 of the 21 cases. A brief outline is given of the printing processes in common use.

Sensitizing potential of urethane (meth)acrylates in the guinea pig.

Urethane (meth)acrylates are used as prepolymers in ultraviolet-curable inks, varnishes and coating formulations for industrial purposes as well as resins for dental applications. The sensitizing capacity of 3 commonly used urethane (meth)acrylates was investigated using the guinea pig maximization test. The study shows that an aliphatic urethane acrylate is not only a more potent sensitizer than an aromatic one, but also more sensitizing than a (meth)acrylated aliphatic urethane.

Contact allergy to 2-hydroxypropyl methacrylate (2-HPMA) in an ultraviolet curable ink

A patient working in an ink laboratory developed dermatitis on his hands. Patch testing revealed contact allergy to the ink used and to 2-hydroxypropyl methacrylate (2-HPMA), the monomer present in the ink. Guinea pig maximisation test (GPM-test) shows that 2-HPMA is a weak sensitizer. The data suggest cross-reactivity to 2-hydroxyethyl methacrylate (2-HEMA) but not to 2-hydroxypropyl acrylate (2-HPA) or 2-hydroxyethyl acrylate (2-HEA).

Allergic contact dermatitis due to urethane acrylate in ultraviolet cured inks.

Seven workers exposed to ultraviolet printing inks developed contact dermatitis. Six cases were allergic and one irritant. A urethane acrylate resin accounted for five cases of sensitisation, one of which was also sensitive to pentaerythritol triacrylate and another also to an epoxy acrylate resin. One instance of allergy to trimethylpropane triacrylate accounted for the sixth case of contact dermatitis in this group of workers. An irritant reaction is presumed to account for the dermatitis in the individual not proved to have cutaneous allergy by patch tests. In this instance trimethylpropane triacrylate was thought to be the most likely irritating agent. Laboratory investigation proved urethane acrylate to be an allergen. The results of investigations of the sensitisation potentials of urethane acrylate, methylmethacrylate, epoxy acrylate resins, toluene-2,4-diisocyanate, and other multifunctional acrylic monomers in the albino guinea pig are presented. The interpretation of such predictive tests is discussed.

Phototoxicity Occurring During the Manufacture of Ultraviolet-Cured Ink

Phototoxicity Occurring During the Manufacture of Ultraviolet-Cured Ink

Phototoxicity occurring during the manufacture of ultraviolet-cured ink

Phototoxicity occurring during the manufacture of ultraviolet-cured ink