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Fleksotiskar je v svojem delu postavljen pred mnoge izzive, da bi zagotovil kakovost odtisa, ki jih ta tehnika tiska zajema v vsakem postopku priprave stroja na tisk in med samim procesom tiska. V diplomskem delu je bila predstavljena tehnika fleksotiska, trendi v razvoju fleksotiskarske panoge, analizirani so bili spletni priročniki, ki so na voljo flekso tiskarjem pri iskanju dejavnikov kakovosti odtisa v procesu tiska. Analiza le-teh je pokazala, da vsi priročniki prikazujejo napake, nekateri imajo napisan vzrok za nastanek ter ukrepe, s katerimi je zagotovljena konsistentna kakovost odtisa. Kljub temu pa v nobenem od priročnikov ni zajetega vsega, kar bi lahko pomagalo fleksotiskarju v celoti razumeti nastanek težave in postopke, kako to težavo odpraviti, da lahko s svojim delom nemoteno nadaljuje. V praktičnem delu so prikazani dejavniki kakovosti, ki vplivajo na odtis v fleksotisku. To je bilo narejeno na podlagi 40-urnega delavnika fleksotiskarja. Spremljani, analizirani so bili dejavniki ter razložen nastanek motečih faktorjev, ki vplivajo na kakovost odtisa. Napake so slikovno prikazane in podane možne rešitve. Flexographic printers face many challenges in their work related to the quality of the print that result from the printing technique. They have to ensure the quality of the print in each step of preparing the machine for printing and during the actual printing. The aim of the following diploma thesis is to present the technique of flexographic printing, trends in the development of the flexographic printing industry and to analyse online manuals available to flexographic printers in terms of print quality factors in the printing process. The analysis of the manuals shows that all manuals present errors, with some of them listing the causes for errors and measures to ensure consistent print quality. However, none of the manuals cover everything that would help the flexographic printer fully understand how the errors occur and the procedures for resolving the problem, so ii that they could seamlessly continue their work. Therefore, the practical part introduces the quality factors that affect the print in flexographic printing. The analysis is based on a 40-hour flexographic workweek. Factors are monitored and analysed, the reasons behind interfering factors that affect the quality of the print are explained, and solutions and possible errors are presented with images.

Purpose The purpose of this study is to prepare, characterise and evaluate nano-emulsions of ter-polymers of various compositions as eco-friendly binders for flexographic ink industry. Design/methodology/approach Various nano-emulsions of ter-polymers were prepared based on Vinyl acetate, Vinyl Versatate, butyl acrylate, acrylic acid and acrylamide monomers by means of a conventional seeded emulsion polymerisation technique, using K2S2O8 as the initiator. The characterisation of the prepared emulsions was performed using Fourier transform infrared, thermo-gravimetric analysis, gel permeation chromatography and transmission electron microscopy. A selection of co-polymers and ter-polymers were formulated with pigments and additional ingredients, as water-based flexographic inks. The inks were characterised for their rheological properties, pH, degree of dispersion, water-resistance and colour density. Findings It was found that the low viscosity of the prepared polymers may reduce the film thickness of the flexographic inks and may also increase the spreading of the ink on the surface. As a result, stable modified poly acrylate-based latex with improved physico-mechanical properties was obtained. The prepared latexes showed improved properties such as enhanced thermal stability and better water resistance. The effect of the emulsifier type on the properties of the resulting emulsion latexes and their corresponding films were investigated. Also, as the hydrophobic monomer increases, so does the colour density and increasing the binder ratio enhances the gloss values. The improving in gloss values were obtained and provide excellent adhesion properties for both the pigment particles and the base paper. Research limitations/implications The study focusses on the preparation of new water-based ter-polymer nano-particles and their use as eco-friendly binders for flexographic ink industry. Ink formulations based on other different type emulsion polymers could also be studied to assess the applicability of the ink formulation system found for other binders. Practical implications The ink formulations developed could find use in industrial-scale printing. Originality/value Eco-friendly environment and low-cost ink formulations for printing on paper substrates are novel.

PLA films, as non-absorbent materials, require modification of the surface before the printing process in order to improve the wettability of the substrate and to obtain proper ink adhesion to the substrate. In this paper, the surfaces of two kinds of PLA films were modified using plasma activation with parameters enabling high surface free energy (SFE) values, and then the films were printed on using different kinds of flexographic inks. Two gases, oxygen and argon, were used for activation, as these make it possible to obtain good hydrophilicity and high SFE values while having different effects on the roughness, or the degree of surface etching. Plasma-activated films were subsequently subjected to the measurements of: contact angle with water, diiodomethane and three printing inks, roughness, weight change, strength properties, color and gloss change, and SFE was determined. Unmodified and activated films were flexographically printed in laboratory conditions and then the quality of obtained prints was analyzed. The results showed a strong effect of activation with both oxygen and argon plasma on the SFE value of the films and the contact angles of water and inks, with the gas used for plasma activation and the type of film significantly influencing the thickness of the fused ink layer and the resultant color. Moreover, plasma activation had a especially favorable and significant effect on the quality of prints made with water-based inks, while it had little effect when printing with solvent-based inks.

Flexographic printing technology is an economical, productive, low maintenance and versatile technology. However, the removal of these inks by the traditional flotation process during paper recycling is not possible since they remain dissolved in the waters, making necessary the development of alternative methods. Recent studies have revealed the potential use of nanocellulose (NC) combined with a cationic polyacrylamide to remove flexographic inks from wastewater. The use of a natural polymer, such as chitosan, would be an important improvement of this treatment because NC and chitosan are the two most abundant natural polymers with interesting properties, such as non-toxicity and biodegradability. Therefore, in this study the decolorization of three flexographic inks (copper phthalocyanine blue, carbon black and diarylide yellow) by the sequential addition of cellulose nanofibers, produced from recycled paper, and chitosan has been evaluated. Results show that this eco-friendly approach has high potential for the removal of water-based inks with an almost 100% reduction of turbidity and ink from the wastewater. Moreover, the final sludge containing nanocellulose and inks could be used to reinforce the pulp of the middle layers of carton board, improving the mechanical properties of the product and reducing waste generation.

The objective of the research was to investigate colorimetric changes of the waterbased flexographic ink printed on hemp-based papers subjected to artificial ageing. Three types of commercially available hemp office papers were used as printing substrate and by Esiproof instrument were printed manually in full tone with process waterbased flexographic inks. Both, papers and prints were exposed to artificial ageing in the Suntest XLS+ test chamber according ASTM D 6789-2 standard. The L∗, a∗, b∗ colour coordinates were measured and ΔE00 colour difference was calculated for different stages of light exposure in order to determine the change from the original color value. In total exposure time was 96 h. The results have shown how the paper optical stability is dependent upon manufacturing process and that bleached hemp fibers provides better optical stability of papers than unbleached hemp fibers. Further, stability of prints made on hemp-based papers is for the most part defined by ink color, while the impact of the printing substrate is less pronounced. Generally, it was noticed how the most stable among prints were prints covered with the black ink, while prints with the yellow ink had the greatest changes in color under the influence of light.

The challenge to prevent the counterfeiting of documents and the development of flexible printed electronics are two thrust research areas that demand innovative techniques. This study reports the use of fluorene-based Schiff base (FBH) prepared via a simple, one-step and cost-effective method as a thermally stable and biocompatible pigment for environment-friendly, water-based flexographic ink for potential application in security printing and flexible printed electronics. The flexo ink coating and print on the UV dull security paper were invisible in the daylight but displayed bluish-green fluorescence under UV light. Moreover, the emission colour of the print was sensitive to changing pH, which further imparted the eco-friendly ink formulation an excellent covert performance that could be exploited for anti-counterfeit application. The functional ink formulation can also be smartly-utilized in stamp/ink pads to obtain invisible fingerprint for detecting forgery. The colorimetric, and densitometry studies, abrasion resistance and surface morphology analysis of both the coated and printed paper samples were also investigated. The electrical measurements of the prints on flexible and low-cost paper substrates with good mechanical properties exhibited high charge carrier mobility with p-type semiconductivity for use in organic printed transistors. This new functional ink could thus be a promising candidate for anti-counterfeiting applications, including food packaging, documents, labels and ink pads, as well as in secure printed electronics.

In pursuit of fluorescent pigments, a pyrene-based chalcone 1-(4-chlorophenyl)-3-(3a1,6,8a,10a-tetrahydropyrene-1-yl)prop-2-en-1-one (CPP), which exhibited aggregation-induced enhanced emission was synthesized. Water-based eco-friendly flexographic inks were formulated using CPP (in batch ink) and Luminous yellow RG-3 (in standard ink) as pigments. The batch and standard inks were coated on security paper and printed on security and packaging papers as well as boards. The printed substrates displayed yellow fluorescence upon excitation under UV light. The gloss, light-fastness, abrasion resistance and colorimetric values of the batch ink were superior to that of standard ink. The study revealed the potential of CPP as a fluorescent pigment for security printing applications, optical-electronic devices such as transistors, anti-counterfeiting labels, etc.

There is growing interest in making printing inks more sustainable, and lowering the overall carbon footprint of the printing industry. A recent surge of research activity has emerged to develop “green” inks with bio-based solvents and binders, but little attention has been given to replacing the pigments that give inks their distinctive color. In this study, flexographic inks were formulated by replacing carbon black with a more sustainable biochar pigment derived from recycled paper, and fast growth cycle wood pulp. Obtained from fossil fuel sources, carbon black imparts high quality black prints, but at a significant environmental cost. Biochar, derived from recycled and renewable resources, has the potential to replace carbon black in many applications. Canceled United States currency stock was pyrolyzed at 1600 °C to produce a black biochar. Eastern White Pine (Pinus strobus) was selected for comparison, and converted to biochar at 550 °C and 1600 °C. Each biochar was functionalized and formulated into a simple ink composition optimized for flexographic printing. Prints exhibiting reflective optical densities exceeding 1.0 with excellent tone reproduction were obtained. Comparable print quality was achieved on both coated and uncoated paper substrates. Although further work would be required to fully optimize a biochar ink to match current print industry standards, a viable pathway for sustainable black ink development with good black density derived from recycled resources has been demonstrated. Our results indicate that it is possible to replace fossil fuel-based carbon black with biomass derived biochar, potentially resulting in cleaner production of flexographic printing inks.

Novel waterborne UV-curable hyperbranched polyurethane acrylate/silica (HBWPUA/SiO2) nanocomposites were prepared by a three-step procedure and sol–gel method. 1H NMR and 13C NMR results indicate that HBWPU is successfully synthesized. Surface tension and contact angle tests both demonstrate the good wettability of the nanocomposites. Besides, the kinetics of photopolymerization of HBWPUA/SiO2 films were analyzed by attenuated total reflection-Fourier transform infrared spectroscopy, which reveals that the modified SiO2 could accelerate the curing speed of HBWPUA coatings. Thermal gravity analysis indicates that the HBWPUA/SiO2 hybrid films have a better thermal stability than the pure HBWPUA cured films. Furthermore, the hybrid films show enhanced pencil hardness, abrasion resistance, and adhesion. On the basis of the above, HBWPUA/SiO2 nanocomposites were finally applied to waterborne UV-curing flexographic printing ink, which is printed on poly(ethylene terephthalate) and glass. The nanocomposite presents good rheological behavior because the ink has a lower Z0, a higher Z∞, and the viscosity rebuild time is 375 s. Three colors (red, yellow, and blue) of ink were used to test its printing quality, the curing time was below 30 s, and the adhesion was excellent without being stripped. All of the inks show good water resistance and abrasion resistance. Moreover, the red and blue inks possess better solid densities than the value of 1.07 of yellow ink, and are 1.83 and 1.84, respectively. The current study suggests that the process has promise in applications of food packages.

The objective of the research was to investigate whether the addition of pearlescent plate-like parallel orientated particles have any impact on the light-fastness of the ink layer. Nine different pearlescent pigments were used in the studies, among them five silver, three gold and one red. Different amounts of these pigments such as 5%, 15% and 25% were added to the water-based flexographic ink. The samples were printed on two different bases, non-absorbent PE activated foil and absorbent gloss coated paper base then accelerated light aged in the Suntest CPS + device. The L ∗ , a ∗ , b ∗ colour coordinates were measured and ΔE ∗ ab colour difference was calculated for different stages of light exposure. The total exposure time was 72 h. The novelty of this research is that it was proved that the majority of pearlescent pigments tested based on mica coated with metal oxides improve the light-fastness parameter. In the case of gold pearlescent pigment tested in the research by as much as up to 45%. This behaviour was observed especially with the greatest amount of pearlescent pigment added to the ink base especially those with high amounts of iron oxide (Fe 2 O 3 ) and titanium dioxide (TiO 2 ) platelets. It was also proved that the size of pearlescent pigments impacts the light stability. This results may have an application in the ink manufacturing process. The improvement of ink light-fastness parameter due to the pearlescent pigment presence may be caused by its specific ability to reflect light thus it could be a form of protection for other colour pigments in the ink composition.

Developing printed optoelectronic devices based on metal oxide inks requires synthesizing stable suspensions of the desired materials. In this work, pure and manganese doped zinc oxide inks were synthesized by a top-down wet milling route and the role of solvent in ink stabilization and printing was analyzed. Fluid properties of the as-prepared inks were measured and used for studying jettability criteria for inkjet printing. Among the various solvents evaluated, ethylene glycol produced stable oxide inks and satisfied the jetting conditions. The inks were evaluated using a commercial drop-on-demand piezoelectric inkjet printer. The morphology of the patterns printed on glass substrates, for various ink volumes, was investigated and was found to be continuous and showed good optical transmittance. We also investigated the particle segregation in these inks using a custom built direct writing system. This top-down approach, by separating the material development and ink synthesis, can be extended to a variety of metal oxide based inks.

Non-reactive polyamides were prepared by reacting dimer fatty acids and, two different diamines such as ethylenediamine and isophornedimine, to obtain a product. The dimer fatty acid used was of dimer/trimer/ Monomer mixtures, ≥80/≤18/≤5. all the polyamides prepared, the number average molecular weight (Mn) ranged from 2479-2803, weight average molecular weight (Mwt) from 6761-10220, Z weight average molecular weight(Mz) from 13532-26876, and the most fundamental characteristic of a polymer its molecular weight distribution(PDI) degree of polymerization ranged from 2.727-3.713, and the glass transition was 76.46-98.9°C. Evaluation gloss and color strength polyamides in ink on films (paper, polyethylene milk, and polyvinylchloride). Most of these polyamides have properties comparable to the commercially available polyamides used in flexographic inks.

We considered pattern formation, i.e. viscous fingering, in the ink splitting process between an elastic flexographic printing plate and the substrate. We observed an unexpected scaling behavior of the emerging pattern length scale (i.e., finger width) as a function of printing velocity, fluid viscosity, surface tension, and plate elasticity coefficients. Scaling exponents depended on the ratio of the capillary number of the fluid flow, and the elastocapillary number defined by plate elasticity and surface tension. The exponents significantly differed from rigid printing plates, which depend on the capillary number only. A dynamic model is proposed to predict the scaling exponents. The results indicate that flexo printing corresponded to a self-regulating dynamical equilibrium of viscous, capillary, and elastic forces. We argue that these forces stabilize the process conditions in a flexo printing unit over a wide range of printing velocities, ink viscosities, and mechanical process settings.

Prerecycling of water-based flexographic ink and water-based thermal inkjet inks was explored. Model laboratory formulated water-based flexographic and commercial water-based thermal inkjet inks were used in experiments using solely wet or dry inks. The goal was to optimize ink detachment during repulping and at the same time assure its minimal ink redeposition. Ink’s behavior was examined under a wide pH range. An alkaline environment is desirable for complete ink detachment from the printed substrate, whereas the benefit of an acid environment is the agglomeration of the pigment in water-based ink. Deinking would be most efficient if executed in two steps: first, alkaline to detach most of the alkaline water-based ink and second, acidic to maintain detached ink coagulated. Acidic pH has the ability to agglomerate the pigment, once it is detached and present in deinking waters. However, such a recycling protocol is likely not achievable in current recycling plants.

The aim of the work described in this thesis is to characterize the structure of coatings and prints, and to validate models for the optical response and interaction of ink and coating based on optical measurements of physical samples. It is the interactions between the printing ink and the porous structure of the coating layers that are subject to investigation. Experiments have been employed to relate the physical conditions in a flexographic printing nip to the ink setting and the resulting optical response.By comparing simulated and measured results, it was shown that modifications of the surface properties account for the brightness decrease when substrates are calendered. Light scattering simulations, taking into account the surface micro-roughness and the increase in the effective refractive index, showed that surface modifications accounted for most of the observed brightness decrease, whereas the bulk light scattering and light absorption coefficients were not affected by calendering.Ink penetration affects the print density, mottling and dot gain. Results show that ink distribution is strongly affected by surface roughness, differences in pore size and pore size distribution. For samples having different latex amounts and different latex particle sizes, a higher print force did not increase the depth of penetrated ink to any great extent, but rather allowed the wetting to act more efficiently with a more evenly distributed ink film, a higher print density and fewer uncovered areas as a result. Uncovered areas could be linked both to local roughness variations and to local wettability variations on the surface. Samples with different ratios of calcium carbonate/kaolin clay pigment showed an increased porosity and an increase in print density with increasing amount of kaolin in the coating layer.

The last decade has seen a significant increase in research on UV curable digital inks for industrial printing applications with the focus to expand this technique into new markets. However, most of the commercially available inks are based on acrylic monomers, which provide a significant toxicological behavior limiting their applicability in promising fields, e.g. printing on food packaging materials. In this study, a variety of biocompatible monomers based on vinylcarbonate building blocks were evaluated regarding their application in UV curable digital inks. Although, the viscosity and surface tension of these monomers is appropriate for ink-jet printing, the curing speed is far too low for high speed printing processes. In order to circumvent this limitation, thiol-vinylcarbonate formulations were prepared that offer reactivities and double bond conversions (DBC) similar to those of acrylates. For that purpose, a multifunctional thiol was synthesized providing both, low odor and an appropriate low viscosity facilitating the formulation of basic ink-jet inks, which offer excellent jetting behavior, together with good film forming properties and adhesion on PET. Although there are some challenges regarding stability, in particular for pigmented formulations, this system represents a promising alternative to commercially available acrylate based inks.

The ink-jet printing has been widely applied in the decoration of ceramic tiles in last ten years since its excited characteristics provide the possibility to produce the customized ceramic tiles with higher image definition at a lower cost in a shorter duration. The number of ink-jet printers in operation worldwide increased rapidly in recent years. Besides the printer, one of the critical factors for an effective printing is inks. This paper focuses on the ceramic ink and reviews recent development on the preparation of ceramic inks by various methods, such as sol–gel, reverse microemulsion, polyol, hydrothermal and mechanical grinding. Some aspects for future development are proposed based on the application of ceramic inks in industries.

The aim of this research is to discover such a strategy so that Ink-jet Printing of polyester and cotton blended fabric. This research focuses to develop inks by the combination of Reactive and disperse dyes and by using eco-friendly co-solvents. This paper covers a brief introduction of Ink jet printing technologies and types of inks. A summarized study of the evaluation amid ink jet printing as well as rotary screen printing is also given. In addition to, requirements and composition of water-based ink-jet inks focusing on methodology is given. Furthermore, shelf lives of inks, image sharpness, surface tension, color fastness to rubbing, analysis of head with some personal experiences are also discussed.

Paper recycling systems based on flotation technologies are not efficient to deink secondary fibers from new printing technologies based on flexographic inks which, even being more environmentally friendly, still present some recycling problems. We have evaluated the efficiency of a biotechnological approach, based on the laccase-mediator system, for biodeinking of three flexographic inks (Blue 1, Magenta HX-E and Red 48:4) in the presence of several pulps (bleached pulp, deinked paper pulp from secondary fibers and pulp from commercial uncoated and coated office paper sheets). Two fungal laccases, one from the basidiomycete Coriolopsis rigida and the other from the ascomycete Myceliophthora thermophila , were used as catalysts in the presence of HBT (1-hydroxybenzotriazole) or methyl syringate, as models of synthetic and natural mediators, respectively. Higher decoloration rates were achieved for Blue 1 and Magenta HX-E than for Red 48:4. The best results were obtained using bleached pulps without additives. Then, to identify the chemical compounds that may hamper enzymatic biodeinking, the influence of several additives on ink decoloration and enzyme activity was tested. Only calcium carbonate slowed down ink decolorization by up to 40%, although it also decreased the mediator assisted enzyme deactivation. In this work, a system to evaluate the efficiency of the laccase-mediator system in biodeinking of flexographic inks in the presence of different pulps and papers has been developed.

Over the last years many printing ink manufacturers moved toward more sustainable inks. Drivers for this development are besides resource scarcity and a higher legislative burden, an increasing environmental awareness throughout the population and as a result a growing demand for inks with a small ecological foot print. Thus, water-based and UV-curing systems have already started to replace solvent-based inks, which results in a reduction of volatile organic compounds (VOC) released during the printing process. In addition, materials derived from renewable resources, are more frequently used to replace petrochemical ink ingredients, such as polymeric binders, solvents and different additives. These developments often go hand in hand with an economical benefit as these inks allow for reduced drying times and lower equipment cost to name but a few. Nonetheless, many inks are still mainly derived from petrochemical feedstock. This review gives an overview of the developments in the field of printing inks derived from renewable materials, discusses advantages and drawbacks of the systems described and addresses problems unsolved so far.

The formula of water-based ink is designed to study the performance of defoamers of water-based flexographic ink on plastic. Four kinds of defoamers which are mineral oil, silicone-free polymeric, polysiloxane and polyether modified polysiloxane. Effect of defoamer on the ink is discussed, such as defoaming of different kinds of defoamers, defoaming speed, defoaming persistence. Defoamer test methods are used stirring-in air by dissolver and gradient experiments. The results show that F6 which is polysiloxane and F8 which is polyether modified polysiloxane have good performance. Inks have best performance on the BOPP film when F6 and F8 are used 0.8 and 0.6wt% respectively.

This article analyzed and studied the effects of different types of coalescing agent on gloss of plastic water-based flexographic ink. As one of the most important characters for plastic water-based flexographic ink, gloss determines the quality of the flexo-printing products. It is significant for plastic water-based flexographic ink to improve the film quality and reduce the dosage of coalescing agent. We mainly studied on the influence of mass fraction of alcohol coalescing agent (A1), esters coalescing agent (A2) and esters coalescing agent (A3) in plastic water-based flexographic ink. The results indicated that the best dosages of the three kinds of coalescing agents are 1.4, 1.0 and 1.0%. The gloss is increasing 5.2, 14.6 and 10.3% respectively. The esters coalescing agent (A2) have notable effect on the gloss of the ink.

An optical properties of the flexographic prints on the shrink sleeve has been experimentally investigated. Two main materials of shrink sleeve: PVC and PET were used for the research. Films were printed using UV flexographic inks. The color changes arised during shrinking of the films were analysed. Investigations were done using CMYK and PANTONE color matching systems. Color characteristics CIE L*a*b* and color difference DE at different shrink level of the film was estimated. It was found that colors become darker during the shrinking of the film. In the case of rasterize image it is related to the deformation of the raster dots, decrease of the spaces between the raster dots and other factors. The biggest changes in the CMYK color system was determined in the Yellow color, while in the tested PANTONE color system – in the blue (P 290) color. The smallest changes in the CMYK color system was determined in the Cyan color, while in the PANTONE color system – in the white color. Santrauka Eksperimentiškai ištirtos fleksografiniu spaudos būdu atspausdintų atspaudų ant susitraukiančių plėvelių optinės savybės. Tyrimui naudotos dvi pagrindinės susitraukiančioms plėvelėms naudojamos medžiagos: PVC ir PET, užspausdintos ultravioletiniais (UV) dažais. Išnagrinėti spalviniai pokyčiai, atsirandantys plėvelei besitraukiant. Tyrimai atlikti su CMYK ir PANTONE sistemų spalvomis. Nustatytos spalvinės charakteristikos CIEL*a*b*ir spalvų skirtumas DE, plėvelei susitraukiant skirtingai. Nustatyta, kad, plėvelėms besitraukiant, spalvos tamsėja. Rastruotuose vaizduose tai susiję su rastrinių taškelių deformacija, tarpų tarp rastrinių taškelių sumažėjimu ir kitais veiksniais. Didžiausi spalviniai pokyčiai CMYK spalvinėje sistemoje nustatytiYellow(geltonoje) spalvoje, o tarp tirtų PANTONE sistemos spalvų – mėlynoje (P 290) spalvoje, mažiausi pokyčiai CMYK sistemoje nustatytiCyanspalvoje, o PANTONE sistemoje – baltoje spalvoje. Reikšminiai žodžiai:fleksografinė spauda, CMYK spalvinė sistema, PANTONE spalvinė sistema, PET plėvelė, PVC plėvelė, UV dažai.

A novel roll-to-roll flexographic printing process for rechargeable zinc-based battery manufacturing was presented in this paper. Based on the fundamental operating mechanism of flexography, key criteria for developing functional flexographic printing inks were established, including composite ink rheology (steady-state viscosity and yield stress), ink wettability as well as ink dispersing qualities. A variety of MnO2 cathode inks were developed and analyzed comprehensively based on these criteria. A novel type of aqueous cathode ink based on PSBR polymeric binder showed excellent flexographic printability as well as promising electrochemical performance.

With the development of printing technology, greater emphasis has been laid on environmentally friendly materials. Due to its printability and environmental friendliness, Water-based flexo ink is gradually gaining popularity at home and abroad, and has been widely applied in the field of printing. Different from other kinds of bills, scratch-type invoices have an additional scratch area on the surface, which highly covering performance is required for the ink applied. This paper emphatically analyzes and discusses: (a) flexo water-based covering ink and its application in scratch-type invoice covering region printing; (b) how to explore and evaluate new developed green inks. Compared with traditional inks, the water-based flexo ink is free of emissions of volatile organic compounds (VOC), and its popularization might have significant meanings for the environment protection and sustainable development.

Trametes versicolor laccase papers were prepared, and their suitability was tested for anticounterfeiting and oxygen indicator concepts in packaging applications. Laccase was coated and printed onto paper with a flexographic ink base, a sulfo polyester resin, Hydro-Rez 1100D (HZ1100D). Laccase remains active on paper with flexographic ink HZ1100D after printing with flexographic press. Colour change of papers was observed when 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) solution was applied to the paper. A strong colour change to dark green was obtained on the papers prepared by coating or printing of laccase with HZ1100D onto EUCA paper. EUCA paper appeared to be well suited for laccase-based indicator applications because it remained rough even after ink deposition, allowing rapid absorption of ABTS solution. Finally, the indicators demonstrated to work as oxygen indicators in a package. Indicator colour was changed when oxygen was leaked to the package. As a conclusion, the laccase papers described here would be well suited for various indicator applications and could be produced using flexographic printing, allowing large scale manufacturing. Copyright © 2014 John Wiley & Sons, Ltd.

Barrier properties of packaging materials against moisture and oxygen penetration are of high relevance. Enhanced protection of existing materials against weather conditions can be achieved by application of printed coatings. To improve barrier performance of packaging materials, new inks for obtaining printed coatings with a layered structure were developed and investigated. The proposed ink compositions for flexographic printing on paper substrates are based on an environmentally friendly acrylic binder and contain inorganic fillers with platelet particles incorporated in the polymer matrix. Coatings based on the developed printing inks demonstrate significantly decreased water vapour permeability compared to traditional polymer inks. The effect of decreased permeability was investigated considering inks rheological behaviour, the coating structure, mechanical properties, surface energy and water uptake for different ink formulations. The developed inks provide variable optical properties including coatings with a relatively high transparency. The development of the functional barrier inks contributes to saving natural resources by prolonging life performance of packaging materials and goods.

As printing technology advances, environmentally friendly consumable printing materials have been explored. Water-based ink has become a new research hotspot due to its printability and environmental friendliness. Resin is an important part of water-based ink which functions as the carrier of the pigments. Its performance directly affects the printability of the ink. In order to obtain optimal ink formulation, different resins were applied and tested. This paper emphatically analyzes and discusses: (a) different resins and its performance in water-based covering ink; (b) cultivate an evaluation and rating system of resins applied. The water-based ink does not contain volatile organic compounds (VOC), which makes it to the benefit of environment protection and sustainable development.

This paper analyses the influence of content of printing inks (and different materials used in their production) on work surrounding and the environment, with the special review on eco inks usage. Printing ink presents dispersive system made of number of different components (pigments, vehicle, adhesive materials, aid materials etc.), which all brought together give specific properties suitable for the printing. During production, ink components are put under intensive homogenization and create a paste of specific consistency. Printing inks contain different kinds of organic and inorganic matter, which can be emitted to the air, soil and water, sometimes causing long-lasting damages to the environment. Beside that, toxic and dangerous vapors from inks violate quality of working surrounding and present the threat for employees in printing facilities. Pigment gives color in printing process and presents the most important constituent of the printing ink. Pigment usually contains different heavy metals, while some oils contained in inks, present distillation derivates of crude petroleum and are dangerous substances which might be cancerous. From the aspect of environmental protection, optimal content of printing ink is unavailable to determine, because each printing technique dictates its own demands in printing - quality and printing speed (connected with the properties of ink drying). Thus, the possibility of substitution dangerous substances in printing inks by less dangerous or harmless is limited. Printing process is sensitive to the paper and ink properties, the way of paper production was done and the origin of other repro materials in printing industry. It is the fact that 'eco inks' can't achieve the same results and quality in printing as traditional inks. In that reason, some other measures can be also effective in protecting employees and the environment from the harmful effect of printing inks constituents. Uprising the consciousness of employees and the management of the printeries, conducting of preventive measures and measures for occupational safety present the main moto for socially and environmentally responsible printing business. The highest responsibility in preserving lives and the environment is on the state itself - to implement laws, to concern about their enforcement and to encourige and stimulate printeries to use recycled materials and eco inks.

The current work deals with the effects of incorporation of silver nanoparticles on the antibacterial and the thermal properties of a flexographic ink. The stable and uniform dispersion of silver nanoparticles in the ink were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The thermal properties of the pure and nanoparticle loaded ink films were also evaluated using TGA and DSC techniques. The results from this study proved acceptable dispersion characteristics, wherein, the flexographic ink showed a significant antibacterial activity against Gram-positive and Gram-negative bacteria

Flexographic printing process has been established as a very competitive printing method and a broadly used printing technique. Consequently, as a more demanding packaging printing has to be performed, flexographic printing process became a strong competition to the gravure printing process. It is a quality and cost-effective printing technique used in respect to various types of substrates. This research analysis was focused on testing flexographic prints on six different polymer materials. Namely, it is mandatory for good quality prints to have good coverage even at low film thicknesses when printed on the printing substrate and the previously printed ink film, respectively. Therefore, the acceptance of cyan ink to the different polymer printing substrates and acceptance to the previously applied white ink were analysed. A number of samples of cyan ink acceptance with various viscosities were compared with each other by using spectrophotometric values converted into colorimetric values L*, C*, h˚.

The Christian Doppler Laboratory (CDL) for Functional and Polymer Based Ink-jet Inks was founded in January 2012 by the Chair of Chemistry of Polymeric Materials (University of Leoben, Austria), together with the DURST Phototechnik DIT GmbH (Lienz, Austria) as industry partner. The research program of the CDL aims at novel concepts for UV curable ink-jet inks, with a strong focus on non-toxic and eco-friendly materials. These new ink-jet inks enable advanced applications in the fields of optics and bio-medicine. For that purpose, alternative radical based curing reactions are explored on a fundamental level to substitute the precarious (meth)acrylate monomers/oligomers in ink formulations. In collaboration with the industry partner DURST, these novel monomers are explored for the realization of conventional ink-jet inks, which are food-proof and can thus be used for the printing on food packaging materials and labels, and also for ink-jet printing on textiles and garments.

Ink transfer and ink penetration into a coated surface, and variations thereof, influences the print density, mottling and dot gain, which affects the achievable print quality and visual appearance ...

Flexographic printing inks form electrosterically stabilized colloidal dispersions in water that display extreme stability at the alkaline pH values of most wastepaper deinking systems. A significant amount of U.S. newspapers are now printed using water-based flexographic inks, and the residual inks from these sources are problematic to remove in deinking plants. A successful flocculant for flexographic ink particles used in deinking plant filtrate streams requires that both the electrostatic and steric components of colloidal stabilization be eliminated simultaneously. The present study shows the advantageous characteristics of cupric chloride in achieving rapid flocculation of flexographic inks. Flocculation experiments were performed with a model ink as well as a mixture of offset and flexographic inks from recycled newspapers. The critical coagulation concentration of cupric chloride has been compared to other chloride, nitrate, and copper salts. Copper(II) chloride has been found to be significantly more effective than other such salts in achieving destabilization and aggregation of flexographic ink particles. A possible flocculation mechanism of flexographic ink particles by cupric chloride is presented.

In order to improve the anti-friction performance of water-based flexographic ink, we made up different kinds of water-base flexographic ink by changing the kinds of film-forming resin or adding different kinds of friction resistant additives, and then evaluated the friction resistant performance of the ink by the rate of density decay. According to analysis the influencing factors of the anti-friction performance of ink, aiming at improving the cohesion of molecular systems and smooth degree of membrane surface, and reducing the friction coefficient as well. The result shows that different molecular structure of film-forming resin ink will cause different cohesion of molecules system in ink, which impacts the ink friction performance. Adding appropriate anti-friction performance additives can improve ink cohesion of molecular system, and improve the ink anti-friction performance as well.