Ink Adhesion Research Articles

Development of Digital Quasi-embossing Technology with an Inkjet Printer-2

Conventional embossing printing technology which can be used to produce metallic glossy images on stereo-shaped objects needs a pressing plate with the image patterns specially arranged. Accordingly, the embossing system is relatively expensive and lacks the adaptability for high-mix low-volume production. Considering these facts, we developed the Digital Quasiembossing Technology (DQT) which consisted of the technology combined with UV-curable inkjet printing and hot foil-stamping. We reported the DQT for the first time at NIP 28 in Quebec City last year. This paper is a continuation of the last report and describes the following facts. (a) We have improved the adhesion of UV-curable ink to a metallic foil, and consequently we can make not only relatively small-sized products but also large-sized ones with pictures and letters printed thereon. (b) The improved DQT system can produce higher gloss than the last system reported at NIP 28.

The Research on Ink Adhesion of Vacuum Aluminized Paper

In this paper we evaluated some surface characteristics of the Vacuum Aluminized Paper (VAP) to explore the ink adhesion on it. It is shown that this performance is quite unsatisfying due to the high gloss of the VAP which results in an even weaker surface energy than the surface tension of ink. The optimal drying time for the inked VAP under UV light with 125W of power is approximately 4.5 minutes, converts to the practical production, the printing speed of the VAP should be near to 7128 sheet/hour so as to fully solidify the UV ink thus acquires the optimal adhesion of ink.

Effect of PVP(polyvinylpyrrolidone) on the Ag Nano Ink Property for Reverse Offset Printing

Among the various roll-to-roll printing technologies such as gravure, gravure-offset, and reverse offset printing, reverse offset printing has the advantage of fine patterning, with less than 5 <TEX>${\mu}m$</TEX> line width. However, it involves complex processes, consisting of 1) the coating process, 2) the off process, 3) the patterning process, and 4) the set process of the ink. Each process demands various ink properties, including viscosity, surface tension, stickiness, and adhesion with substrate or clich<TEX>$\acute{e}$</TEX>; these properties are critical factors for the printing quality of fine patterning. In this study, Ag nano ink was developed for reverse offset printing and the effect of polyvinylpyrrolidone(PVP), used as a capping agent of Ag nano particles, on the printing quality was investigated. Ag nano particles with a diameter of ~60 nm were synthesized using the conventional polyol synthesis process. Ethanol and ethylene glycol monopropyl ether(EGPE) were used together as the main solvent in order to control the drying and absorption of the solvents during the printing process. The rheological behavior, especially ink adhesion and stickiness, was controlled with washing processes that have an effect on the offset process and that played a critical role in the fine patterning. The electrical and thermal behaviors were analyzed according to the content of PVP in the Ag ink. Finally, an Ag mesh pattern with a line width of 10 <TEX>${\mu}m$</TEX> was printed using reverse offset printing; this printing showed an electrical resistivity of 36 <TEX>${\mu}{\Omega}{\cdot}cm$</TEX> after sintering at <TEX>$200^{\circ}C$</TEX>.

Characterization of Silver Inkjet Overlap-printing through Cohesion and Adhesion

We introduce an understanding of silver (Ag) inkjet overlap-printing characteristics from the viewpoints of cohesion between ink droplets and adhesion between an ink droplet and a surface. The printing characteristics were closely monitored by changing the surface energy to elucidate the effect of adhesion and cohesion on printing instability, such as droplet merging and line bulging. The surface energy of the substrate was changed through the hydrophilization of a hydrophobic fluorocarbon-coated surface. The surface energy and ink wettability of the prepared surfaces were characterized using sessile drop contact angle analysis, and printing instability was observed using an optical microscope after drop-on-demand inkjet printing with a 50% overlap in diameter of deposited singlet patterns. We found that the surface energy is not an appropriate indicator based on the experimental results of Ag ink printing on a hydrofluoric-treated silicon surface. The analytical approach using adhesion and cohesion was helpful in understanding the instability of the inkjet overlap-printing, as adhesion and cohesion represent the direct interfacial relationship between the Ag inks used and the substrate.

Influence of Resin on the Performance of Water-Based Plastic Gravure Ink

Resin as an important part of water-based plastic gravure ink which directly affect the performance of ink. In order to improve the performance of water-based plastic gravure ink，fixing other components and changing the type of resin to prepare ink. Viscosity of ink was measured. Proof the ink on PET film and the effect of resin on water-based plastic gravure ink was inspected through measuring adhesion, wear resistance and glossiness of the ink. The results indicate that water-based plastic gravure ink was prepared by acrylic resin S-2661D has low viscosity, high glossiness; water-based plastic gravure ink was prepared by acrylic resin 2661-91-3 has better ink adhesion, wear resistance performance.

LDPE/EVA Modified Film Prepared by Melt Blend Method and Study of its Mechanical Performances and Barrier Property

In this study, six kinds of different films from LDPE (Low-density polyethylene) modified by EVA (Ethylene - vinyl acetate copolymer) were made, and EVA / LDPE mass ratio was 0/50, 1/49, 1/ 19 4/21, and 1/3. Influence of EVA amount on the properties of LDPE film was investigated using the Instron universal testing machine, DSC, oxygen permeability tester and breathable apparatus. The mechanical properties of the blended films showed that when the EVA content was 5%, LDPE / EVA film transverse Young's modulus increased by about 50%, and the vertical Young's modulus increased by about 56%, which is good for improving the overprint accuracy of the LDPE / EVA film. DSC analysis showed that the melt blending has no effect on the thin-film processing temperature and thermal stability, but the result indicated that the crystallinity of the blended films was lowered with the increase of EVA amount. Barrier tests showed that with the increase of EVA content, the barrier of the modified films was decreased. The polarity of the film increased with more EVA component, which would augment the surface tension of LDPE and its ink adhesion.

Investigation to the Influence of Water-based Ink Adherence

In order to improve the adhesion of water-based ink, adopt different kinds and contents of resin, adhesion promoter and base material wetting agent to compound water-based ink. Test the contact Angle of ink on CD, and coating the ink on CD to test the adhesion of ink. The results of the study show that: the kinds of resin has a great influence on the adhesion of water-based ink; right kind of resin and adhesion promoter matching can effectively enhance the adhesion of water-based ink; the wettability and adhesion of ink has a certain relationship, wettability is necessary condition of adhesion of ink, adding appropriate contents of base material wetting agent can improve the adhesion of ink.

Abrasion Resistance of Aqueous Pigmented Inkjet Inks on Coated Paper

High-speed water-based inkjet printing has recently made inroads into traditional commercial printing because of its reasonable cost and environmental friendliness. In the commercial printing fields dealing with magazines, fliers, and brochures, low penetrative gloss coated paper is generally used. When inkjet droplets are impacted on that type of paper, their liquid components evaporate and penetrate into the paper very slowly, while solid components, such as pigment and polymer, are filtered and form an ink layer on the paper. Since impacted droplets dry slowly and the formed ink layer is directly exposed to external forces, abrasion resistance of inks on coated paper is a serious problem in comparison with that on porous plain paper. In this study, the mechanism of abrasion resistance of pigmented inkjet inks on coated paper was investigated in terms of surface friction, strength of ink layer and adhesion to substrate. The result indicated that the strength of ink layer was the major factor, and we could impressively improve abrasion resistance performance by controlling that factor from a rheological view point

Study on Preparation and Properties of Nano-Modified Polypropylene

The printing and packaging properties of ordinary Polypropylene (PP) materials were modified by self-made nanometer silicon dioxide (SiO2) and the effects of different SiO2 proportion were investigated. The results showed that SiO2 modification not only greatly increased the mechanic properties of PP but also improved its universal performance including polarity, ink adhesion and solvents residual and therefore enable PP materials better meet the requirement for food packaging industry.

Synthetic paper from plastic waste: Influence of a surface treatment with corona discharge

AbstractPolymers generally have a chemically inert surface, are nonporous, and have low surface energy, which is characterized by their relatively weak adhesion to other materials. Numerous methods have been developed to modify polymer surfaces chemically. This study was an investigation of how the surface energy of synthetic paper (composite film) could be altered after treatment by corona discharge and of the stability of the surface energy of a film produced from postconsumer polypropylene (PP). A PP/filler (70/30 w/w) composite film was processed in a single‐screw extruder with a flat‐film dye. In this study, the film stretching rate and electric charge potential of the film surface treatment were the process parameters analyzed. The results showed that the conditions of the surface treatment by corona discharge and the presence of a filler (calcium carbonate) influenced some surface properties: the contact angle, surface energy, and ink adhesion. The surface energy of the composite film increased from 38.7 × 10−3 N/m2 without treatment to 52.3 × 10−3 N/m2 with treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Coating Formulations for Digital Printing; Applications of Phase-Change Inks

Hot melt/phase-change inks have gained popularity by imparting high print quality. As hot melt inks differ from other digital and conventional inks in terms of properties and mechanisms of transfer onto a substrate, there is need for developing low cost substrates compatible with these solid inks. As these inks solidify upon contact with the substrate, there is little absorption of the ink into the substrate. Thus, the print quality and associated color gamut are less sensitive to the substrate than that for aqueous ink jet printers.It is well known that the surface properties that influence the print quality vary for different printing processes. Thus, the substrate-ink interactions must be well understood. Some of the important surface properties of a substrate include permeability, porosity, surface energy, roughness, opacity, brightness and gloss. These properties are known to influence final print quality and color gamut. Adhesion of ink on paper also plays a vital role. In addition, economics play a vital role. The paper specially formulated for phase-change inks sells for about 50 &#xA2; per sheet in comparison to 2-5 &#xA2; per sheet for water-based inkjet papers. Thus, there is a need for the development of lower cost substrates compatible with solid inks.

Adhesion and anti-adhesion of viscous fluids on solid surfaces—A study of ink transfer mechanism in waterless offset printing

The transfer of a liquid under dynamic conditions onto a solid surface relies on wetting/adhesion under transient external forces. We found the phenomena associated with forced wetting and dewetting could not be explained by thermodynamic approaches which are based on surface energy and work of adhesion. This is because these approaches do not take account of the dynamic nature of the forced wetting and dewetting. This study uses ink transfer in waterless offset printing as an example to present a new understanding of adhesion and anti-adhesion of a liquid to a solid surface under dynamic conditions. We focus on the adhesion strength, instead of work of adhesion, at the ink–plate interface and experimentally quantified ink adhesion forces on the image and non-image areas of the printing plate. Based on adhesion force measurements we proposed that the formation of a weak boundary layer and/or the softening the non-image area due to solvent swelling are likely to be the mechanisms that causes ink refusal on the non-image area. AFM images are presented to show changes of the non-image surface before and after contacting with ink.

豚枝肉における体表由来汚染のインク着色による検討

To examine the contamination process of the surface of animal carcasses in a slaughterhouse, the surface of the body of a hog was colored with stamp ink, and the degree of ink adhesion to the carcass during each process was observed. The main cause of ink adhesion (contamination) during each process was first cutting of the partial peeling, removal of the anus and full skinning, or runoff by wash water from the hanging upper body. Bacterial contamination on carcass areas with ink adhesion was significantly higher than it was on areas with non-adhesion. Since contamination of a carcass by full skinning covered a broad range, contamination can be significantly reduced by closing the upper discharge spout of the skin stripper wash water. This examination showed the bacterial contamination to workers and proved extremely useful for hygiene education.

Novel Phase Change Inks for Printing Three-Dimensional Structures

Based on recent progress, nonimpact printing techniques can deliver the next generation of materials for an extensive set of novel applications. A novel hot melt ink composition, useful for three-dimensional (3D) printing comprising different waxes, tackifier and plasticizer resins, rheology modifiers, and gas releasing agents, was designed. The behavior of the inks was comparable to commercial hot melt inks without gas releasing agents. The hot melt ink properties promise a possibility of use in a conventional phase-change printer in order to create 3D printed structures. Differential scanning calorimetry was used to evaluate thermal properties of the ink components and the extensive study of the thermal behavior of the proposed gas releasing agents has been carried out. The rheology behavior of inks was measured, and printability analysis, such as image detail, definition of dots (height, sharpness of the edges), dot formation, and spreading were investigated. Rub resistance tests were also used together with tape adhesion tests for ink adhesion monitoring.

Synergy between Printer, Ink, and Media for Digital Printing I: Effect of Vinyl Thickness has on Image Quality vs. Cost

The billboard customers of Cooley Group noticed that printed image quality, dry-time, and ink adhesion are proportionally better with increasing vinyl thickness on the surface of our reinforced wide-format media.To best serve our customers, and to position ourselves better in the marketplace, we undertook a study to determine the underlying cause of the quality difference and to identify whether the surface is smoother or the chemistry on the surface changes.Our investigation relied heavily on quantitative image quality measurements and chemical analysis of the surfaces of prints made on various substrates with differing vinyl thickness.This paper will detail our process in identifying the root cause of this change in image quality. Technical data will be presented and analyzed.

Ink‐Coating Adhesion: The Importance of Pore Size and Pigment Surface Chemistry

The characteristics of ink vehicle absorption into porous structures has formed the basis of a number of recent studies. Kalela, Ridgway and Gane (11th International Printing and Graphic Arts Conference, Bordeaux, 2002) considered an example of common impression cylinder deposits as a result of poor coldset ink adhesion especially in the presence of excess fountain solution. These studies centre on the absorption mechanisms of pigmented coatings and how these can be adjusted to enhance ink‐coating adhesion. By developing techniques of tack cycle analysis and correlation with adhesion, i.e. observing print density on the pull‐off areas using the ink‐surface interaction tester (ISIT), it has been possible to assess ink‐coating adhesion. To enhance the adhesion properties of inks, two strategies for coating designs are discussed. The first is to increase the number of ultrafine pores and to increase simultaneously the pigment surface area to enable a capillary‐driven separation of oils from solved resins and to provide higher adsorptive power for resins. This was tested by the inclusion of a novel surface‐structured calcium carbonate. The second is to introduce an oleophilic species into the coating structure, achieved by the inclusion of hydrophobic talc via a co‐structure between talc and hydrophilic dispersed calcium carbonate (Gane, Buri, and Blum, International Symposium on Paper Coating Coverage, Finland 1999). Mercury porosimetry measurements of model coatings using these pigment combinations are used to illustrate their effect on coating structure. These structures are modelled using a computer network simulator, an absorption algorithm is applied to generate the absorption dynamic for each structure. The differences in wetting front are illustrated. It is seen that only at the shortest timescales is there any difference in the absorption dynamic (ignoring any surface chemistry effects). It can therefore be concluded that the observed improvements in this study of ink adhesion are related to adsorptive mechanisms, and absorption rate governs the dwell time over which this adsorption can occur.

Hot Melt Inks for 3D Printing

A unique modified formula of hot-melt ink for phase change printing process was developed. A composition useful for 3D printing comprises different waxes, tackifier and plasticizer resins, rheology modifiers, and UV curable resin and/or gas releasing agent. Differential scanning calorimetry was used to evaluate thermal properties of the ink components and the extensive study of the thermal behavior of the proposed gas releasing agents has been carried out. The rheology behavior of inks and printability such as image detail, definition of dots (sharpness of the edges), dot formation, and spreading were investigated.Dot heights were measured by a modified method using a First Ten Angstrom dynamic contact angle instrument. Sutherland Rub resistance test was also used together with tape adhesion tests for ink adhesion monitoring.

QUANTITATIVE EVALUATION OF ADHESION STRENGTH OF INK DEPOSITED ON PLASTIC FILMS WITH A NANO INDENTER AND A SCANNING PROBE MICROSCOPE

As our lifestyles change, the convenience food industry booms. Many convenience food products use flexible, boilable, and microwavable plastic packaging. Almost every package is printed with ink, promoting what is inside the package, listing ingredients and nutrition data, giving preparation instructions, etc. The adhesion of ink on plastic films merits increasing attention to ensure quality packaging. However, this property has not been systematically studied and lacks a scientific method to measure the adhesion strength quantitatively. We are developing a technique of using a Nano-Indenter and a Scanning Probe Microscope to evaluate the adhesion strength of ink deposited on plastic films. It shows promise, and the measurement will be helpful in better understanding the adhesion mechanism, thus giving direction as to how to improve the adhesion.

A new understanding on the mechanism of fountain solution in the prevention of ink transfer to the non-image area in conventional offset lithography

In conventional offset lithographic printing, it has been well established that the existence of a continuous layer of fountain solution (FS) on the surface of the non-image area is an essential condition to ensure correct operation of lithography. However, the mechanistic function of FS in preventing the ink from being transferred onto the non-image area has not been fully understood. Several major mechanistic interpretations can be found in the literature, which are based either on comparing of static works of adhesion and cohesion of ink and FS, or on the splitting of the 'weaker' FS layer. Although the latter becomes more accepted, direct experimental evidence is difficult to find in the literature. On the other hand, confusing information found in the literature showed that the ink-transfer (or non-transfer) observations reported in many case studies correlate well with simple comparisons of works of adhesion, cohesion and spreading data of ink/FS, ink/plate and FS/plate obtained under the static condition. These results, therefore, imply that, in explaining the function of FS in preventing ink transfer to the non-image area, the ink/FS interfacial adhesion failure would be the dominant mechanism. The work presented in this study covered two specific areas in order to address and better understand the responses of ink and FS layers and their interface to forces encountered during ink transfer. Firstly, an analysis of lithographic plates contaminated with a cationic polymer revealed that the violation of the ink non-transfer condition of the plate non-image area due to contamination could be predicted by traditional criteria of plate wetting and works of adhesion and cohesion. However, these traditional criteria cannot reliably predict the non-transfer condition of the ink on the clean non-image area that was covered by FS. Secondly, in some novel experiments conducted in this study using ice or Teflon as a substrate, the works of adhesion and cohesion were not able to predict ink transfer in most cases. Direct experimental evidence from this work revealed that splitting of the FS layer was involved in the prevention of ink transfer to the non-image areas, and that the thickness of the FS layer was critical in allowing the splitting to occur.

Adhesion at Toner - Paper Interface in Electrophotographic Printing

In all printing processes, the quality of ink adhesion is of primary importance to ensure legibility and permanence of the transmitted information. However, contrary to other processes that use a fluid ink penetrating the support, electrophotography consists in depositing a fine layer of powder containing pigments and fusing it to paper. The mechanisms involved in obtaining good adhesion at toner / paper interface have thermal, rheological and physico-chemicals origins.In this paper, the three main mechanisms of adhesion are reviewed, namely mechanical anchoring, adsorption and diffusion. Experimental modifications of paper roughness, surface energy and diffusion potential are described and analysed in order to determine the dominating parameters to achieve good toner adhesion.For the complete paper see the 2004 Proceedings for the 56th TAGA Annual Technical Conference.