Oil-based Inks Research Articles

Optical tuning of copolymer-in-oil tissue-mimicking materials for multispectral photoacoustic imaging

Objective. The availability of tissue-mimicking materials (TMMs) for manufacturing high-quality phantoms is crucial for standardization, evaluating novel quantitative approaches, and clinically translating new imaging modalities, such as photoacoustic imaging (PAI). Recently, a gel comprising the copolymer styrene-ethylene/butylene-styrene (SEBS) in mineral oil has shown significant potential as TMM due to its optical and acoustic properties akin to soft tissue. We propose using artists’ oil-based inks dissolved and diluted in balsam turpentine to tune the optical properties. Approach. A TMM was fabricated by mixing a SEBS copolymer and mineral oil, supplemented with additives to tune its optical absorption and scattering properties independently. A systematic investigation of the tuning accuracies and relationships between concentrations of oil-based pigments and optical absorption properties of the TMM across visible and near-infrared wavelengths using collimated transmission spectroscopy was conducted. The photoacoustic spectrum of various oil-based inks was studied to analyze the effect of increasing concentration and depth. Main results. Artists’ oil-based inks dissolved in turpentine proved effective as additives to tune the optical absorption properties of mineral oil SEBS-gel with high accuracy. The TMMs demonstrated long-term stability and suitability for producing phantoms with desired optical absorption properties for PAI studies. Significance. The findings, including tuning of optical absorption and spectral shape, suggest that this TMM facilitates the development of more sophisticated phantoms of arbitrary shapes. This approach holds promise for advancing the development of PAI, including investigation of the spectral coloring effect. In addition, it can potentially aid in the development and clinical translation of ultrasound optical tomography.

Development of xanthan gum intelligent oil-in-water ink and its application in pork freshness preservation

To optimize the stability of oil-based inks and ensure their wide application in freshness indication, new natural indicator inks were prepared using a stable oil-in-water structure. This study selected natural Lycium ruthenicum anthocyanin as the dye and glucose as the pigment carrier. Soybean oil was introduced as a linker and xanthan gum as a thickener, and an oil-in-water ink with the function of freshness indication was successfully developed. In ensuring the safety of ink labels for use on food packaging, particular attention is paid to the origin and properties of the materials used. All ingredients are of food-grade or bio-friendly provenance, thereby ensuring the safety of the product when in direct contact with food. We measured the viscosity, particle size and fineness of the ink for micro characterization and evaluated its macro printing performance by its printing effect on A4 paper. According to the experimental results, when the water-oil ratio of the ink is 10:5, the average particle size of the emulsion system is 822.83 nm, and the fineness reaches 5 μm. These values are relatively low, which indicates that the stability of the ink system is high at this time, and the ink shows excellent rheological and printing characteristics. With this water-to-oil ratio, the ink can show the best results when printed on A4 paper, clearly displaying image details. In addition, in fresh pork applications, inks with a 10: 5 water-to-oil ratio provide an accurate and highly sensitive indication of the freshness of pork. When the freshness of the pork changes, the ink color responds promptly. This high sensitivity makes the ink ideal for use as a food freshness indication tool, providing consumers with an intuitive and reliable reference for pork freshness. As a further innovation, combining this ink-printed label with a WeChat app not only allows consumers to know the freshness of the food in real-time but also tracks the supply chain information of the food, providing a more comprehensive application prospect for freshness-indicating products.

Covalent crosslinking chemistry for controlled modulation of nanometric roughness and surface free energy.

Smooth interfaces embedded with low surface free energy allow effortless sliding of beaded droplets of selected liquids-with homogeneous wettability. Such slippery interfaces display low or moderate contact angles, unlike other extremely liquid repellent interfaces (e.g. superhydrophobic). These slippery interfaces emerged as a promising alternative to extremely liquid repellent hierarchically rough interfaces that generally suffer from instability under severe conditions, scattering of visible light because of the hierarchically rough interface, entrapment of fine solid particulates in their micro-grooves and so on. However, a controlled and precise modulation of surface free energy and nanometric roughness is essential for designing a more compelling solid and dry antifouling interface. Here, we have unprecedentedly demonstrated the ability of covalent cross-linking chemistry for precise and simultaneous modulation of both essential surface free energy (∼49 mN m-1 to ∼22 mN m-1) and roughness (root mean square roughness from 30 nm to 3 nm) of a solid interface for achieving liquid, substrate, and process independent, robust slippery properties. The strategic selection of β-amino-ester linkage through a 1,4-conjugated addition reaction between amine and acrylate groups of a three component reaction mixture (dominated by a 61% (w/w) crosslinker) under ambient conditions provided a facile basis for associating various important and relevant properties-including self-cleaning ability, anti-smudge properties (against both water and oil-based inks), thermal stability (>300 °C), chemical stability, physical durability, optical transparency (∼95%) and so on. The embedded slippery properties of the coating remained unaffected at both low (0 °C) and high (100 °C) temperatures. Thus, the prepared coating would be appropriate to maintain the unperturbed performance of commercially available solar cell modules and other relevant objects under outdoor conditions.

Studying the Methods to Determine the Age of Ink: A Critical Review of Ink Dating Methods

On the basis of the type of ink, pen inks are classified as ballpoint pens or non-ballpoint pens. Ballpoint pen inks are oil-based inks (ballpoint pens). While non-ballpoint pen inks are water-based inks (gel pens, fountain pens, pilot pens, fibre tip pens, etc.). Different approaches related to the determination of the age of ink were proposed in the literature, including ballpoint pen inks, non-ballpoint pen inks and stamp pad inks. This study provides a comprehensive appreciation of analytical research studies that were published from the year 2000 to year 2020 on the determination of the age of inks. Owing to contemporary technological advancements, the process has been developed in many folds. However, its reliability is questioned due to the variability in methods and results. Research works related to the aging of ink have been compiled to assist the researchers and the forensic document examiners and to provide an overall insight regarding the works done so far. In an attempt to unravel this issue of questioned document examination, a critical and systematic review of the literature is proposed to encourage the usage of various tools and techniques necessary to establish the age of ink in different case works.

Flotation de-inking for recycling paper: contrasting the effects of three mineral oil-free offset printing inks on its efficiency.

Paper for recycling has become a promising raw material for the pulp and paper industry due to its low cost and because it is conducive to sustainable development. Unfortunately, recycled paper contains a high volume of printed paper that is difficult to deink, which restricts its applications. Flotation deinking plays an essential role in the product quality and process cost of wastepaper recycling. This study was performed to evaluate the deinkability of environmentally friendly offset inks by flotation deinking. For this purpose, three mineral oil free series of four-color inks, namely, hybrid light emitting diode ultraviolet (LED-UV), LED-UV, and vegetable oil-based inks, were printed on white lightweight coated papers under laboratory conditions. The deinking methodology involves repulping, deinking agent treatment, flotation, hand sheet making, and evaluation of the produced hand sheets. The obtained results indicated that the hybrid LED-UV prints had the best deinkability. After flotation deinking, the deinking efficiency and the whiteness of the hybrid LED-UV ink increased by 58.1% and 47.6%, respectively. LED-UV ink had a 46.9% increase in the deinking efficiency and a 37.0% increase in the whiteness of the hand sheet. The deinking efficiency of the vegetable oil-based ink was the lowest, at 42.1%, and the whiteness of the hand sheet increased only by 23.8%. The particle size distribution analysis demonstrated that the hybrid LED-UV four-color ink exhibited a larger value of the average particle size than the two other. Scanning electron microscopy revealed that the hybrid LED-UV ink particles on the surface of the fibers were the least abundant after deinking. The physical strength properties of the hand sheets, including tensile index, folding resistance, and interlayer bonding strength of the hybrid LED-UV, LED-UV inks, and vegetable oil-based inks, increased.

Comparison of optical techniques and MeV SIMS in determining deposition order between optically distinguishable and indistinguishable inks from different writing tools

In the forensic investigation of questioned documents, it is often very important to know the deposition order of ink traces from two different writing tools at their intersection on a paper. In the present work, intersections of inks from several writing tools were studied using optical techniques that are standardly applied for questioned documents examination in a forensic laboratory, and an accelerator-based Ion Beam Analysis (IBA) technique called Secondary Ion Mass Spectrometry using MeV ions (MeV SIMS) that is applied in an accelerator facility. MeV SIMS provides molecular information about the studied inks from writing tools, which is an added value and can be also applied for determination of deposition order but was so far relatively rarely used in forensic studies. Aim of this paper is to compare performance of optical techniques and MeV SIMS for several combinations of intersecting lines. Cases were divided into those in which optical techniques can distinguish used inks and those which are optically completely indistinguishable. In the latter cases, we show that although mass spectra of used inks (from blue ballpoint pens) had extremely small differences, these in combination with advanced and most importantly objective multivariate algorithms could be very beneficial in resolving the deposition order at the intersection of optically indistinguishable inks. In general, MeV SIMS proved to be more efficient for oil-based inks while difficulties were encountered with water-based ones, similar to optical methods.

Liquid-like transparent and flexible coatings for anti-graffiti applications

Transparent, durable and smooth coatings with anti-fouling properties are highly desirable for many applications e.g. windows and touch screens. However, most of smooth anti-fouling coatings are limited by complicated preparation and application conditions such as synthesis at high temperatures or curing under ultraviolet irradiation. In this paper, two kinds of siloxane were cross-linked to form a highly transparent anti-fouling coating, which can be rapidly applied on different substrates by a facile brushing process (~3 min for curing) at room temperature. This coating has excellent anti-graffiti properties for liquids with complex components such as water-based and oil-based inks, furthermore, it also exhibits good flexibility, anti-reflection and anti-corrosion properties. The durability test shows that the performance of the coating remains unchanged under various harsh environments. This work would provide a pathway for developing solid and smooth anti-fouling coating, which is expected to be quickly applied in practice due to its simple principle and rapid preparation.

The examination of vegetable- and mineral oil-based inks' effects on print quality: Green printing effects with different oils.

Printing inks oil selection is related to the desired nature of the varnish in the ink production. Petroleum-derived mineral oils and vegetable oils can be used in offset inks. In this study, the behaviors of vegetable- and mineral oil-based inks on uncoated and coated paper surfaces were investigated in terms of printability. Solid tone test prints were done with offset printing of these inks. Print gloss of the printed samples was measured and a light fastness test was implemented on these samples in order to determine the resistance to fading. Absorption behavior and contact angles of the ink-printed films on the test papers were measured with the sessile water drop method depending on time, and surface energies were calculated. On both paper types, linseed-soybean oil-based vegetable ink gave the highest brightness value. The lowest print gloss results on the paper were obtained from soybean oil-based inks. The lowest color change was recorded with mineral oil-based inks on gloss-coated papers. According to the ink-film-surface relation, when the contact angle is high, surface energy decreases and the absorbency of the ink-film is lower. In this study, the behaviors of vegetable- and mineral oil-based inks on different paper surfaces, and the effect on the quality of printability as well as differences, have been evaluated, taking environmental and health factors into consideration.

Gel wax-based tissue-mimicking phantoms for multispectral photoacoustic imaging.

Tissue-mimicking phantoms are widely used for the calibration, evaluation and standardisation of medical imaging systems, and for clinical training. For photoacoustic imaging, tissue-mimicking materials (TMMs) that have tuneable optical and acoustic properties, high stability, and mechanical robustness are highly desired. In this study, gel wax is introduced as a TMM that satisfies these criteria for developing photoacoustic imaging phantoms. The reduced scattering and optical absorption coefficients were independently tuned with the addition of TiO2 and oil-based inks. The frequency-dependent acoustic attenuation obeyed a power law; for native gel wax, it varied from 0.71 dB/cm at 3 MHz to 9.93 dB/cm at 12 MHz. The chosen oil-based inks, which have different optical absorption spectra in the range of 400 to 900 nm, were found to have good photostability under pulsed illumination with photoacoustic excitation light. Optically heterogeneous phantoms that comprised of inclusions with different concentrations of carbon black and coloured inks were fabricated, and multispectral photoacoustic imaging was performed with an optical parametric oscillator and a planar Fabry-Pérot sensor. We conclude that gel wax is well suited as a TMM for multispectral photoacoustic imaging.

Nano emulsion binders for paper coating synthesis and application

ABSTRACTThe key objectives of coating papers and paperboards are to improve their aesthetic appearance and printability. Coatings offer smoothness, gloss, brightness, and opacity to the base papers and provide them with enhanced printability, which requires resistance to ink splitting forces, smoothness, ink holdout and gloss, etc. Styrene acrylate latexes were synthesized, via emulsion polymerization, and were formulated as coats for white and brown recycled papers. Both processes were characterized specifically for offset printing. The prepared latexes showed enhanced solid content, viscosity, zeta potential and appropriate glass transition temperature for paper coating formulation. The porosity, gloss and Cobb60 values of coated papers increased with the increased addition of nano-emulsion modified latexes. The formulations afforded high printability (print gloss and print density) with local ground calcium carbonate compared with that of the imported pigment (kaolin). Furthermore, the synthesized binder had higher water resistance than the commercial one; which can tightly be correlated with print quality, printability and productivity and most significantly, permits usage of low viscous ink. Coated recycled brown base gave promising results with respect to print quality although offset printing was utilized. The novelty of this work was not only in employing the local alternative binder and local pigment but also in achieving compatibility with environmental regulations since oil-based inks and recycled papers were also used.

16TH- AND 17TH-CENTURY ITALIAN CHIAROSCURO WOODCUTS: INSTRUMENTAL ANALYSIS, DEGRADATION, AND CONSERVATION

Italian chiaroscuro woodcuts are among the most technically innovative of Renaissance prints for being printed in color. A woodcut is made from a wooden plank that is carved in relief, inked, and impressed on paper. Chiaroscuro woodcut prints – named from the Italian term for contrasting light and dark tones – involve printing an image from two or more woodblocks, with each block printed in a different color, to create transitional passages of shading. With two to five superimposed layers of colored, oil-based inks printed onto a paper support, the chiaroscuro woodcut is an object of complex stratigraphy. Several centuries of aging and deterioration of both the inks and paper can cause visual changes that affect a print's legibility, thereby distorting the historical and aesthetic interpretation of the work. A correct assessment of the physical characteristics of the printing process and the colored inks deployed, as well as the condition of the woodcut, is therefore fundamental not only to the art-historical evaluation of prints, but equally to the application of appropriate preservation and conservation measures. A technical survey of over 2000 Italian chiaroscuro woodcuts of the 16th and 17th centuries examined in international collections revealed trends in deterioration of colored inks such as discoloration, fading, blanching, and micro-fissures. Seventy-two prints from the Library of Congress, Los Angeles County Museum of Art, and Grunwald Center for the Graphic Arts were examined further using instrumental analysis. The results of this joint study demonstrate the use of unstable colorants such as lead white, verdigris, vermilion, orpiment, and organic pigments. Based on the documented behavior of unstable colorants in oil paint, it is possible to infer how the visual appearance of prints containing such colorants is likely to have changed. The combined evidence is here analyzed in order to establish recommendations for conservation treatment, storage, and parameters for display and equally to inform art-historical interpretation.

Manipulating Oil Droplets by Superamphiphobic Nozzle.

will be reduced and liquid retention on such nozzles is to be avoided, which is of great importance to the development of tiny oil droplets fabrication. We have prepared a superhydrophobic needle nozzle to manipulate water droplets. [ 13 ] However, most functional materials for fabrication of organic solar cells, organic fi eld effect transistors, and organic light-emitting diodes are only soluble in organic liquids with low surface tensions. As organic liquid will spread and wet the water repellent surface, the superhydrophobic nozzle is not able to manipulate such low surface tension liquids. Thus, it is still a challenge to increase the liquid transfer effi ciency of organic liquid. Here, we report a facile strategy to manipulate small organic liquid droplets assisted by a superamphiphobic nozzle. Owing to the superliquid-repellent property of the nozzle surface, oil droplet is restricted at the edge of the nozzle, which avoids the spreading of oil droplet and results in decreased volume as well as increased liquid transfer effi ciency. Furthermore, by utilizing the superliquid-repellent nozzle to directly dispense oil-based inks, high-resolution 3D structures are fabricated, which is of great signifi cance for the development of liquid transportation and ink-jet printing devices. Figure 1 a shows the preparation process of the hierarchically structured superamphiphobic nozzle surface. Copper plates (5 × 5 × 1 mm 3 ) were used as the base material for nozzle fabrication, and holes were drilled through the plates for tiny oil droplet dispensing. Holes with diameters ranged from 20 to 150 μm were prepared by laser drilling (Figure 1 b), and holes larger than 150 μm were fabricated by mechanical drilling (Figure 1 c). To modify the nozzle surface with reentrant micronanostructures, chemical base corrosion was performed, [ 14 ] in which Cu plates were immersed in an ammonium persulfate and sodium hydroxide mixture solution (details about the morphology and wettability of different corrosion time can be seen in Figures S1 and S2, Supporting Information). As shown in Figure 1 d, Cu(OH) 2 microsheets and microclusters with re-entrant structures are achieved. Since surface wettability is controlled by both surface morphology and surface chemical composition, [ 15 ] only a structured route is not enough to realize superamphiphobicity on the nozzle surface. Fluorination was thus used to lower the surface energy. X-ray photoelectron spectroscopy (XPS) spectra demonstrated the successful introduction of fl uorine element on the prepared surface and the conversion of Cu(OH) 2 to Cu(O 2 C 2 H 2 C 8 F 17 ) 2 (Figure S3, Supporting Information). In addition, scanning electron microscope (SEM) images showed that almost no visual morphology change occurred after fl uorination (Figure S4, Supporting Information). DOI: 10.1002/smll.201501021 Oil Droplets

Dielectric Characterization of Pigment Inks for Electrohydrodynamic Jet Printing

This article presents a characterization method that could be useful for evaluating the performance of ink in electrohydrodynamic jet printing. The ink contains pigment particles and polymer (stabilizer for pigments) and has a low viscosity and a low elasticity. Depending on the medium (hydrocarbon for oil-based inks and glycol ether for polar solvent-based inks) and the type of pigment (exhibiting different colors), vast differences were found in the dielectric properties even when the viscosities of the inks were almost identical. These differences between the two series of inks were related to differences in the ion concentration n and ion mobility μ estimated from an analysis of the complex dielectric constant e* (= e′ – ie″) on the basis of Macdonald theory. These differences between the polar solvent- and oil-based inks are discussed in relation to the performances of the inks in electrohydrodynamic inkjet printing.

Effects of Flotation Deinking on the Removal of Main Colors of Oil-Based Inks from Uncoated and Coated Office Papers

This paper presents the results of trials to evaluate the color-stripping behaviour of offset printing colors and the effect of coating on deinking performance. Oil-based four-color inks were separately printed as base printing on coated and uncoated white poster paper, and then extensive pulping and deinking processes were carried out. Standard offset printings were conducted on paper samples using cyan, magenta, yellow, and black colors (CMYK), and the effects of deinking efficiency on the removal of each color were analysed. The pulps were made at Micro-Maelstrom Laboratory Pulper at specified conditions with and without bleaching agents. Formamidin sulfinic acid and hydrogen peroxide formulation were used as reductive and oxidative bleaching agents, respectively. Flotation deinking and thickening of pulp were practiced using Degussa flotation and thickening cell. The changes in the optical properties, such as brightness, whiteness, and color value (CIE L⃰, a⃰ b⃰) of deinked pulp were determined. It was found that optical properties of color-stripped pulps from coated papers were better than that of uncoated office papers. However, yield was quite low in coated papers since fillers were lost during flotation process. Cyan color was found to be the most difficult one in four main color printing inks stripping out in the deinking process.

Evaluation of Plasma-Deposited Hydrophobic Coatings on Pigment-Coated Paper for Reduced Dampening Water Absorption

Hydrophobic plasma coatings were deposited on pigment-coated paper with the purpose of reducing dampening water absorption and create uniform surface chemistry. The influence of plasma coatings on sheet-fed offset printability was also studied. Three plasma chemistries, fluorocarbon, organosilicon and hydrocarbon, were used to adjust the hydrophobicity of paper surface. The plasma coatings reduced, and in some cases prevented, the dampening water absorption into pigment-coated paper in both laboratory and pilot scale trials. Ink transfer, mottle and ink setting were altered due to the presence of the plasma coatings, whereas porosity and surface strength of the pigment-coated papers were not affected. These results suggest that the preferred way to improve the print quality with both mineral and linseed oil-based inks is to use plasma chemistry that modifies the paper surface to be both hydrophobic and oleophilic. Hydrophobic and oleophobic surfaces were found to cause ink repellence. Uniformity of the plasma coatings was crucial for obtaining an even print appearance.

Determination of BTEX by GC–MS in Air of Offset Printing Plants: Comparison between Conventional and Ecological Inks

The use of inks containing organic solvents by the offset printing process implies in the release of volatile organic compounds to the work environment. Many of these compounds such as benzene, toluene, ethylbenzene, and the xylene isomers (well known by the acronym BTEX) are extremely toxic. In this study, the BTEX concentrations were determined in two different printing plants that use distinct types of inks: the conventional and the so-called ecological, which is manufactured based on vegetal oil. Concentration ranges were 43–84, 15–3,480, 2–133, 5–459, and 2–236 μg m−3 for benzene, toluene, ethylbenzene, m + p-xylene, and o-xylene, respectively, for the conventional printing plant. At the ecological printing plant, concentration ranges were below limit of detection (<LD)-31, <LD-618, <LD-1,690, <LD-10,500, <LD-3,360 μg m−3 for benzene, toluene, ethylbenzene, m + p-xylene, and o-xylene, respectively. BTEX concentrations are lower at the ecological printing environment than in the conventional, where mineral oil-based inks are used. However, the worker who cleans the printing matrices is exposed to high concentrations of ethylbenzene and xylenes, due probably to the cleaning product’s composition (containing high amounts of BTEX). Although the BTEX concentrations found in both printing work environments were below the limits considered by the Brazilian Law for Activities and Unhealthy Operations (NR-15), the exposure to such vapors characterizes risk to the workers’ health for some of the evaluated samples, mainly the personal ones.

&lt;p&gt;Green Printing: Colorimetric and Densitometric Analysis of Solvent-based and Vegetable Oil-based Inks of Multicolor Offset Printing&lt;/p&gt;

The purpose of this study was to determine the differences in the measurable print attributes (Print Contrast and Dot Gain) and color gamut of solvent-based (SB) inks vs. vegetable oil-based (VO) inks of multicolor offset printing. The literature review revealed a lack of published research on this subject. VO inks tend to perform (color reproduction) better than petroleum inks; in recent years many printers have come to prefer using VO inks. This research adopted an experimental research method. The experiment was conducted in a computer to plate (CTP) based workflow. During the printing, once the density values met the standard (GRACoL) ink density values, the press was run continuously without operator interference and 1,000 sheets were printed, from which 278 were randomly selected for colorimetric and densitometric analysis. The color gamuts of both inks were derived by using colorimetric data. The comparison of SB inks to VO inks led to the conclusion that the latter provides a greater color gamut. VO inks offer greater color perception in printed images. The densitometric findings make it difficult to draw conclusions about print contrast, as each of the inks had statistically significant higher levels of print contrast for two of the four ink colors. Further study is needed to control the variables.