New printing inks with barrier performance for packaging applications: Design and investigation

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.     

Usability of cellulose-based binder in water-based flexographic ink

Packaging must have a good commercial appearance and is generally obtained by ink transferred to its substrate. It is important that the ink used in packaging printing is produced from environmentally friendly and sustainable raw materials as well as being suitable for the printing system. The increasing demand in the field of printed packaging and the scarcity of resources to meet this demand have accelerated the search for new sources for inks. For this purpose, inks produced in the laboratory using a modified cellulose-based binder, a commercial acrylic resin and a commercial soybean protein were compared with a commercial ink. As a result of the study, it was determined that the printability properties of the ink obtained by using the modified cellulose-based binder were better than the ink obtained with commercial soybean protein. It was determined that it showed printability properties close to the ink produced with commercial acrylic binders. By using modified cellulose-based water-based flexographic ink instead of other commonly used binders, more environmentally friendly sustainable inks can be produced.     

An ecological approach to printing industry: Development of ecofriendly offset printing inks using vegetable oils and pine resin as renewable raw materials and evaluation of printability

Petroleum-based solvents and synthetic resins are used as raw materials for the production of varnish, which is one of the main components of offset printing inks. These petrochemical compounds that are released to the surrounding in printing process demonstrates harmful effects on environment and human health. In the light of these facts, this study was carried out to investigate the use of renewable natural resources for offset printing inks production to lower environmental impacts and protect human health. In this study, different vegetable-based offset printing inks were developed with safflower oil (SO); grape seed oil (GSO) and Pinus pinaster resin (PPR) and printability analysis were performed. To understand the effect of pine resin in the ink formulation an ink sample with mineral oil (MO) was also produced. Printing tests were carried out with coated papers and the IGT C1 offset printability tester. Color, gloss, rub resistance, viscosity and tack values were measured on the test prints. Comparison of results with standard values figured out the suitability of using the newly developed offset printing inks for printing industry. The color difference values of color differences were in range of tolerance value. The density value of SO-PPR ink was found as same with standard values while the density value GSO-PPR and MO-PPR inks were measured close to standards as 1.45, 1.42, and 1.46, respectively. The results of printability analysis demonstrated appropriate utilization of the renewable sources for ecological development of offset printing inks.     

Synthesis of waterborne acrylic copolymer resin as a binding agent for the development of water-based inks in the printing application

In this study, a new waterborne acrylic copolymer resin (acrylic-co-resin) was synthesized to develop water-based printing inks on polyester (PET) film. The synthesized acrylic resin showed good water solubility, high acid value (120 mg KOH/g), about 57% solid content. The developed water-based inks (cyan, magenta, and yellow) exhibited small particle size (<1 μm) and optimum surface energy within required values (31.5, 32, and 30 mN/m) for good adhesion of ink upon PET films. The developed inks also showed good storage stability for 30 days. Further, to evaluate the application performance, the inks were printed on corona-treated PET films at room temperature, and the ink drying time was measured. Further, the inks were printed on the corona-treated PET film to evaluate the application performance. The developed inks showed a short drying time (7–9 s), which indicates their fast drying nature. Moreover, the developed inks showed good printability, color strength, high adhesion, and excellent rub-resistant properties. Thus, the overall results demonstrated the potential of water-based inks in printing applications.     

Single‐phase ink‐jet printing onto cotton fabric

The current commercial application of ink‐jet reactive inks to cotton fabrics requires pretreating with pad liquor containing a thickener, urea and alkali prior to printing. In this study, attempts have been made to develop a reactive ink‐jet print in a single‐phase process by adding an organic salt to the ink formulation and hence removing the need to pretreat fabrics. This approach utilises inks containing both a reactive dye, in this case Procion Red H‐E3B, and an organic salt such as sodium formate, sodium acetate, sodium propionate or tri‐sodium citrate. The behaviour of a novel reactive ink formulation for ink‐jet printing on to cotton fabric was evaluated at different pH vlaues. The results at optimum pH indicated that printed non‐pretreated fabrics with ink containing organic salts exhibited a higher level of reactive dye fixation than printed pretreated fabric containing no organic salt ink. The yielded prints demonstrate excellent colour fastness to washing and dry/wet crocking properties. The light fastness of the printed fabrics was improved by adding an organic salt to the ink formulation.     

Suture Fiber Reinforcement of a 3D Printed Gelatin Scaffold for Its Potential Application in Soft Tissue Engineering

Gelatin has excellent biological properties, but its poor physical properties are a major obstacle to its use as a biomaterial ink. These disadvantages not only worsen the printability of gelatin biomaterial ink, but also reduce the dimensional stability of its 3D scaffolds and limit its application in the tissue engineering field. Herein, biodegradable suture fibers were added into a gelatin biomaterial ink to improve the printability, mechanical strength, and dimensional stability of the 3D printed scaffolds. The suture fiber reinforced gelatin 3D scaffolds were fabricated using the thermo-responsive properties of gelatin under optimized 3D printing conditions (−10 °C cryogenic plate, 40–80 kPa pneumatic pressure, and 9 mm/s printing speed), and were crosslinked using EDC/NHS to maintain their 3D structures. Scanning electron microscopy images revealed that the morphologies of the 3D printed scaffolds maintained their 3D structure after crosslinking. The addition of 0.5% (w/v) of suture fibers increased the printing accuracy of the 3D printed scaffolds to 97%. The suture fibers also increased the mechanical strength of the 3D printed scaffolds by up to 6-fold, and the degradation rate could be controlled by the suture fiber content. In in vitro cell studies, DNA assay results showed that human dermal fibroblasts’ proliferation rate of a 3D printed scaffold containing 0.5% suture fiber was 10% higher than that of a 3D printed scaffold without suture fibers after 14 days of culture. Interestingly, the supplement of suture fibers into gelatin biomaterial ink was able to minimize the cell-mediated contraction of the cell cultured 3D scaffolds over the cell culture period. These results show that advanced biomaterial inks can be developed by supplementing biodegradable fibers to improve the poor physical properties of natural polymer-based biomaterial inks.     

Method for controlling surface energies of paper substrates to create paper-based printed electronics

The creation of practical paper-based electronics requires secured conductivity with conductive silver tracks fabricated on a paper substrate. Various paper properties were explored for obtaining the key parameters intimately related to printed circuit qualities. A comparison of the resistance of silver tracks printed by ink-jet with a tetradecane-based ink of silver nanoparticles among four substrates—photo-quality ink-jet paper, matte-type ink-jet paper, coated offset paper, and uncoated laboratory sheets—implied the importance of pore size, porosity, surface roughness, and surface energy. Paper surface layers with small pore sizes and high porosities produced highly conductive, narrow silver tracks because of quick ink absorption, as observed in the photo-quality ink-jet paper. The surface roughness induced a high resistance to peel-off force at the expense of conductivity, and this improvement in the peel-off resistance is considered to be achieved because of the anchor effect of silver nanoparticle inks which fell into dents present on the rough paper surfaces. The widths of the silver tracks were significantly reduced by controlling the surface energies of the paper sheets. This tendency was remarkable, especially for uncoated laboratory sheets, and thus the conductivities of the silver tracks were successfully improved.     

Rheological Control of the Coffee Stain Effect for Inkjet Printing of Ceramics

The rheology of inkjet printing inks must be well controlled in order to be able to form small droplets. One solution is to use low volume fraction dispersed suspensions, but this leads to a common problem during drying called the coffee stain effect. It is caused by particle migration from the center to the edge of a drying drop and leads to nonuniform printed structures. This article describes an approach, to suppress the coffee stain effect by a sufficiently fast increase in viscosity after deposition. Due to the viscosity limitations during printing, inks with tailored rheology and drying behavior need to be developed. Ceramic inks were prepared and printed. First, a binder was added to study the influence of viscosity on printability and the coffee stain effect. Second, the use of a high vapor pressure solvent for faster drying was investigated. Eventually, an ink with the combination of binder and fast drying agent was prepared. This ink showed a considerable decrease in drying time as well as a rapid increase in viscosity after deposition and was suitable to completely suppress the coffee stain effect. Plateau‐like structures were achieved by adapting the drying temperature to permit particle movement to a certain degree.     

Formulating Pantone colors by unused base inks,formulation software,and a spectrophotometer

Unused base inks that are not going to be used for printing production are considered to be hazardous materials. Their disposal is expensive, and strict environmental regulations should be followed for their disposal. As an alternative, this article describes how spectral data of unused base inks can be gathered and mixed to generate new colors to incorporate them back to print production for small‐volume jobs. In this study, 30 different Pantone colors were selected as target colors. The CIE L*a*b* spectral data of Pantone colors and unused base inks were gathered via a spectrophotometer. A commercial formulation software, based on multiflux theory and CIE L*a*b* color space, was used to formulate ink recipes that contained the base inks. To quantify the performance of ink recipes, they were mixed and printed using an offset printability tester. The CIELAB ΔE*_ab metric, developed by CIE, was used to detect the visual differences between the target Pantone Color and printed colors.     

Tailoring the properties of deposited thin coating and print features in flexography by application of UV-ozone treatment

Printed functional materials are a rapidly growing area of interest for low-cost high-speed device manufacture with flexographic printing seen as a route to achieving this. The relationship between surface tension of the ink and surface free energy (SFE) of the photopolymer plate is a key for optimum performance. However, traditional methods of surface tension modification of the ink/coating often cannot be employed for functional inks. In this research, rapid, permanent modification of flexographic printing plate’s SFE is achieved through controlled UV-ozone treatment, and the effects of the treatment on the polar and dispersive component of SFE are analyzed by Fourier transform infrared attenuated total reflectance spectroscopy, swelling experiments, and roughness measurements. Printing trials using the modified printing plates reveal improved print uniformity and control of deposited ink layer thickness, as well as improved print features—particularly track and pad junctions which can be problematic for printed electronic applications. The ability to rapidly tailor printing plate SFE is of benefit to all volume printing applications. Furthermore, it is of critical importance for functional printing and printed electronics where surface tension of the ink is determined by the functional material and chemical modification is not possible or desirable.     

Improving the Stability of R2R Printed 1‐Bit Code Generator through Spin‐Coated Multilayer‐Encapsulation Method

Roll‐to‐roll (R2R) printed electronic devices have great advantages for developing large scale flexible and disposable devices when compared to current Si‐based technology. For practical realization of these advantages, however, R2R printed devices need to surmount device functionality limitations, most urgently high‐power dissipation and poor device stability. To resolve both imperative challenges at once, herein, an all R2R printed complementary metal‐oxide‐semiconductor (CMOS) 1‐bit code generator with spin‐coated multilayer encapsulation method is developed. In order to print CMOS devices by an all‐R2R gravure printing method, electrical amphoteric property of the single walled carbon nanotube (SWCNT) is utilized to fabricate both p‐type and n‐type SWCNT based thin film transistors (TFTs). In addition, printable encapsulating polymeric materials (CYTOP and FG‐3650) are developed to effectively prevent H₂O permeation. The resulting CMOS 1‐bit code generator is able to continuously operate for 2 h under ambient conditions without any variation in output voltage and frequency.     

反应喷墨打印技术及其在功能材料领域的研究进展

反应喷墨打印技术作为喷墨打印电子技术的重要分支,因其可以在沉积材料的同时可得到器件而受到人们的广泛关注.本文详细阐述了反应喷墨打印技术在功能材料制备领域,特别是在金属材料、高分子材料、无机材料等方面的研究进展,说明了反应喷墨打印用墨水是未来喷墨印刷电子研究的关键技术之一,简要介绍了反应喷墨打印技术与三维打印的联系,指出其在金属电路、有机发光二极管等印刷电子产业领域有广阔的应用前景.     

Evaluation of plant-based oils for production of offset printing ink

The oils and solvents are the main components of the printing ink, and the chemical composition of the ink could be harmful or toxic to human health and the environment. Therefore, there is an increasing demand to develop inks containing green, biobased, sustainable, and renewable raw materials instead of petrochemical substances. In this study, flaxseed oil (FO), pomegranate seed oil, plum kernel oil (PKO), and grape seed oil (GSO) were selected to produce offset printing inks. Pinus pinaster (P. pinaster) resin was also used in the formulation of inks to examine the effects of natural resin on ink together with vegetable oils. The phenolic content was analyzed for the resin and oils to figure out their potential antioxidant and bioactive characteristics. Optical and rheological tests were applied to evaluate the printability of the inks. L*a*b*, ΔE, density, and gloss tests were performed for optical evaluation. The viscosity, tack, and rub resistance tests were applied to perform rheological analysis. The biobased, environmental friendly, and self-drying (cold set) offset printing inks were obtained using natural pine resin and three different plant-based oils FO, PKO, and GSO. The printability analysis of the inks figured out the potential usage of plant-based oils in the offset printing ink formulation.     

Direct Printing of Thermal Management Device Using Low‐Cost Composite Ink

This work presents a new method for fabricating thermal devices, such as heat sinks, using a 3D printing technique and lightweight composite ink. The method focuses on formulating composite inks with desired properties and direct ink writing for manufacturing. The ink undergoes two phases: phase one uses low viscosity epoxy to provide viscoelastic properties and phase two provides the fillers consisting of carbon fiber and graphite nanoplatelets to provide high thermal conductivity and structural properties. By combining these functional materials, 3D structures with a high thermal conductivity (≈2 W m⁻¹ K⁻¹) are printed for thermal management applications with the storage modulus of 3000 MPa and a density only 1.24 g cm⁻³. The results show that by carefully tailoring functional properties of the ink, net‐shape multifunctional structures can be directly printed for thermal management device applications, such as heat sinks.     

Influence of nano‐coated pigment ink formulation on ink‐jet printability and printing accuracy

Pigment ink was formulated with nano‐coated pigment dispersion, prepared via mini‐emulsion polymerization. To study the effect of nano‐coated pigment, surfactant and humectant on ink‐jet printability, the trajectory of droplets with different pigment ink composition was monitored. The effect of ink formulation on the accuracy of printing process of the pigment ink was discussed by study on line width and edge contour of printed patterns. Experimental results indicated that the additives and properties of the pigment ink had a great influence on droplet formation and precise positioning of the printed patterns. The optimal composition for the pigment ink as following: nano‐coated pigment dispersion was 20% w/w, surfactant (S‐465) was 1.5% w/w, humectant (diethylene glycol) was 30% w/w and defoamer (FB‐50) was 0.1% w/w. The prepared pigment ink exhibited excellent freeze–thaw, thermal and centrifugal stability. In addition, the optimal formula was beneficial to form a stable droplet and obtain high precision patterns.     

Der Einfluß von Wachsen auf die Eigenschaften,insbesondere die Scheuerfestigkeit von Druckfarben

The influence of Waxes on the Properties of Printing Inks The influence of waxes on the properties of printing inks and printed materials is shown with the examples of straight chain and differently branched hydrocarbons. The waxes in finely dispersed state are imbedded in the printing inks like pigments and retain this state in the dried printing ink film. Polyethylene waxes change the rheological behaviour of the printing inks and above all improve the scratch and scrubb resistance of the finished prints. On the basis of measurements carried out with printing inks and printed matter it has been tried to explain the mechanism of the action of polyethylene waxes on the printing inks.     

The use of natural (Pinus pinaster) resin in the production of printing ink and the printability effect

Alkyd resins are generally used in the production of printing inks. All industries look for alternative raw materials in the production of ink with the growing inclination toward using natural products. Resins forming the vehicle of the ink to be obtained from natural resources will provide benefits for the environment, nature, and living creatures. The aim of the study was to promote the use of natural resin in the ink system. Natural Pinus pinaster resin was added into vegetable and mineral oil-based solvents in pure form with alkyd resin in different amounts and ink varnishes of different combinations were prepared. Then, printing inks were produced from these varnishes in pure and hybrid form. Following the assessment of the rheological properties of the inks prepared, printing tests were conducted to assess the printing quality parameters. Ideal mixing ratios of the natural resins in the ink were determined for printability. The environmental importance and advantages of the use of natural resins were discussed. Recommendations were given in line with the results to encourage widespread use of natural resins in near future.     

UVA and UVC modification of photo polymeric surface and application for flexographic deposition of thin coatings

The object of this research was to perform, characterize, and apply the functional modification of flexographic photo polymeric printing plate surface by UVA and UVC post‐treatments. Photo polymeric printing plates have an important application in functional printing, where new printing inks/coatings and substrate formulations are used and the specific qualitative requirements must be met. The limitations of materials and processes often require expensive reformulations of the functional inks to achieve printability. Results of this research showed that the modification of the photo polymeric printing plate surface at the end of its production process can be used to precisely adjust the printing ink transfer to the printing substrate and thus eliminate the need for changing the ink/coating composition. By applying specific UV post‐treatment, one can create a flexographic coating deposition system of tailored properties adjustable to variable reproduction systems with high quality requirements. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43526.     

Printability of Sized Kenaf (Hibiscus cannabinus) Papers

This article reviews the effect of chitosan, cationic starch and polyvinyl alcohol as sizing agents to improve printability properties of kenaf handsheets. The polymers were incorporated into the sheets by spray application. This study clearly demonstrated that the use of chitosan could improve the printability and print quality of kenaf paper in terms of water and oil absorption, ink penetration, print density and gloss for offset printing. Both PVA-sizing and cationic starch sizing gave print densities and ink penetrations than were intermediate between chitosan and the unsized control sheet, which gave the lowest values for these properties. Kenaf paper sized with chitosan gave the best mix of desirable printing paper properties and was superior to kenaf papers sized with either cationic starch or PVA.