Effect of pigment colour on the printing performance of synthetic leather using a ultraviolet‐curable water‐borne polyurethane acrylate binder

The effect of pigment colours, cyan (C), magenta (M) and yellow (Y), and a blend of these (CMY blend) on the printing performance of synthetic leather using a ultraviolet (UV)‐curable water‐borne polyurethane acrylate binder and two types of photoinitiators was investigated. The curing process was carried out at different radiation doses using gallium and mercury UV lamps in combination. The performance of the prints was evaluated with abrasion resistance, crock fastness, gloss and hardness values and K/S. Chemical changes in the cured film structures due to UV curing were analysed by Fourier Transform–infrared spectroscopy measurements. The highest hardness values for clear and pigmented cured films were obtained with a gallium and mercury lamp combination at the highest energy density (1529 mJ/cm²). The highest K/S was obtained for the sample printed with the formulation including the C pigment and cured under a gallium and mercury lamp combination at low energy density (398 mJ/cm²). The M‐pigmented film displayed the highest hardness and abrasion resistance, whereas lower values were obtained with films pigmented with Y and C, and CMY blend, successively. The highest dry and wet crock values were obtained with the formulation including the M pigment. CMY‐pigmented film showed the highest gloss values at all energy densities. The pigment colour affected the curing degree of printed films due to the different absorption/transmission intervals of each colour in the UV spectrum.     

Light stability in cyan and magenta tones using standard and highly chromatic toner particles

An increasing requisite regarding the reproduction quality of electrophotographic printing machines demands improvement of new electrophotographic toner formulation, especially used pigments. The subject of this paper is a comparison of prints realised by depositing high chroma (HC) and standard emulsion aggregation (EA) toner on gloss fine art paper. HC toner has a different composition of the cyan and magenta tones compared with the corresponding standard EA toner tones and therefore behaves differently under real conditions. The patches used for this experiment were cyan and magenta tone prints with tone values (TVs) of 0, 20, 60 and 100%. Ultraviolet (UV) degradation was measured over time intervals of 0, 6, 12, 24, 48, 96, 144 and 240 h for all patches. Results (laboratory values) were calculated using colorimetric difference. Values were plotted as a function of time in tonal degradation graphs. A model was created using non‐linear regression‐based modelling. The experiment demonstrates that magenta patches are more susceptible to degradation in comparison with cyan patches. With the increase in tonal value, it is noticeable that the colorimetric difference is higher. Colorimetric differences calculated using HC magenta toner and standard EA cyan toner (100% TV) were higher than ?E = 5, starting to appear after 6 h of exposure to UV radiance. After 12 h of exposure, colorimetric differences of standard magenta tones that were greater than ?E = 5 also started to appear. Cyan patches (100% TV) printed with HC toner were more stable than the other patches, and after 240 h of exposure had not crossed the boundary of ?E = 5.     

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.     

Preparation of core‐shell latexes for paper coatings

Novel core‐shell latices with a partially crosslinked hydrophilic polymer core and a hard hydrophobic shell of polystyrene were prepared to improve optical properties of coated paper such as gloss and brightness. These core‐shell latices were prepared by sequential addition of a monomer mixture of styrene, n‐butylacrylate and methacrylic acid. Different crosslinkers were used to form the polymer core and in the second stage styrene to form the hard shell component. In addition, attempts were made to further improve optical properties by introducing a new polymerizable optical brightener, i.e., 1‐[(4‐vinylphenoxy)methyl]‐4‐(2‐phenylethylenyl)benzene during polymerization either into the core or into the shell. The prepared core‐shell latex particles were used as specialty plastic pigments for paper coating together with kaolin as the primary pigment. The runability of paper coating formulation by either using a laboratory scale Helicoater or pilot scale JET‐coating machine was very good. The produced coated papers were printed on both sides employing a heat set web offset (HSWO) printer to study the quality of image reproduction in terms of print gloss, print mottle, print through, etc. The core‐shell latices improved the overall print quality. Furthermore, the results demonstrated that by optimizing polymer composition one can significantly enhance the optical properties and surface smoothness of coated paper. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Uneven Ink Absorption and Its Relation to Drying of Coated Papers

The aim of this work was to study mottling in offset printing. The papers studied were coated and princed LWC-papers.The base paper was obtained from a commercial source. Both macroscopic and microscopic analyses were performed.The conventional macroscopic methods take into account variations in nm-cm scale while the microscopic methods consider the nm-pm scale.

The used conventional methods could not emplain mottling. Microscopic studies, however, revealed that mottling could be a problem caused by varying coat weight and surface structure.

The influence of different drying strategies was also studied. The beet print result was obtained on paper where the drying was relativeiy intense in the beginning of the process and mild during the coating color immobilization stage. Uneven binder migration was not found in these samples.     

Uneven Ink Absorption and Its Relation to Drying of Coated Papers

ABSTRACT

The aim of this work was to study mottling in offset printing. The papers studied were coated and princed LWC-papers.The base paper was obtained from a commercial source. Both macroscopic and microscopic analyses were performed.The conventional macroscopic methods take into account variations in nm-cm scale while the microscopic methods consider the nm-pm scale.

The used conventional methods could not emplain mottling. Microscopic studies, however, revealed that mottling could be a problem caused by varying coat weight and surface structure.

The influence of different drying strategies was also studied. The beet print result was obtained on paper where the drying was relativeiy intense in the beginning of the process and mild during the coating color immobilization stage. Uneven binder migration was not found in these samples.     

Transparent UV-cured clay/UV-based nanocomposite coatings on wood substrates: surface roughness and effect of relative humidity on optical properties

The esthetic durability of coatings on wood surfaces of components constituting wood furniture used in bathrooms is generally affected by high humidity. In this study, surfaces of yellow birch wood (Betula alleghaniensis Britton) were protected with three different types of transparent UV-cured multilayer coatings (MCs), namely MC1, MC2, and MC3. Each MC consisted of three layers: primer, sealer, and topcoat. MC1, MC2, and MC3 contained, respectively, 0, 1, and 3 wt% of nanoclay (NC) in the topcoat, while no nanoparticle was added in the primer and sealer. The surface roughness of coated wood surfaces was measured before accelerated aging and optical properties (color and gloss) were investigated before, during, and after accelerated aging. Statistical results have shown that: (1) all coated wood samples have a similar surface roughness and (2) NC in the topcoat does not have a significant effect on initial color, whereas its effect on initial gloss is significant. There is a significant effect on relative humidity (RH) on color changes, but not between the different types of MCs. With respect to gloss, a lowering of gloss retention with the increase in aging time and RH has been observed for all coatings on wood surfaces. Significant differences appear only at high RH between: MC1 vs MC3 and MC2 vs MC3.     

The effect of gloss on color

A model was developed for the effect of gloss on reflected color, taking the measurement geometry of the color measuring device into account. It considers the total front surface reflectance of a given sample to be independent of gloss and determined only by its refractive index and the angle of the incident beam. Although the total front surface reflectance is fixed, its specular component increases (and the diffuse component decreases) with increasing sample gloss. Therefore, the diffuse reflectance factor measured by a spectrophotometer decreases with sample gloss. In this article, a defined curve was fitted to the measured reflectance factor of black xerographic print samples having a range of gloss values for the 0/45 and diffuse spectrophotometer geometries, and this curve was used to predict the CIELAB color values for samples of the other colors at various gloss levels. The predicted color was compared to the measured color for cyan, magenta, yellow, red, green, and blue images that spanned a wide range of gloss. The RMS color error between the predicted and measured color of all of these images was found to be about 3 CIELAB ΔE* units. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 369–376, 1999     

Colour and gloss properties of pigment‐printed synthetic leather using an ultraviolet‐curable water‐borne polyurethane acrylate binder and two photoinitiators at different ratios

This study reports on the colour and gloss properties of pigment‐printed polyurethane‐based synthetic leather using an ultraviolet (UV)‐curable water‐borne polyurethane acrylate binder and two types of photoinitiators (Omnirad 819 DW and Omnirad 500) at different ratios. The UV curing of printed synthetic leather samples was conducted with gallium and mercury lamps, either singly or in combination, at three different power levels. Chemical changes in the cured films because of the polymerisation of the UV‐curing process were analysed by Fourier Transform‐infrared spectroscopy, which showed that the polymerisation reaction occurred after UV curing in both the clear and in the pigmented films. The Omnirad 500 photoinitiator is more effective in surface curing and the Omnirad 819 DW photoinitiator is more effective in deep curing. The Omnirad 500 photoinitiator caused the gloss values to drop significantly, especially in the formulation including both photoinitiators, Omnirad 819 DW and Omnirad 500, at a 1:2 ratio, respectively. In the formulation including a higher ratio of the Omnirad 819 DW photoinitiator, higher gloss values were obtained compared with the formulation including a higher ratio of the Omnirad 500 photoinitiator. Considering all the results, the highest gloss value of 20.96 was obtained with samples printed with the formulation of the two photoinitiators at an equal ratio (1:1) cured under a gallium/mercury lamp combination at a power level of 90 W/cm. Moreover, the highest K/S value of 10.86 was obtained with samples printed with the formulation of the two photoinitiators at an equal ratio cured under the gallium lamp at 90 W/cm.     

The effect of paper appearance on printed color of inkjet printer

Paper properties, including the chemical or optical characteristics influence the quality and colorimetric characteristics of final printed colors. In this study, the effect of gloss, texture, and whiteness of the paper on the printed colors were investigated. The study was applied on 10 coated papers with different texture, gloss or whiteness, and the same grammage using two inkjet printers. It was found that the reproducibility of the printer can be affected with the paper brand, and this effect is statistically dependent on the brand of printer. The kind of paper significantly influences the light fastness of the final printed colors, and this effect statistically depends on the printer. Although, the paper's properties such as gloss and whiteness affect the gamut volume, it is not totally possible to model this effect. The effect of paper on the colorimetric values of the final printed colors is statistically significant. However, the influence of the brand of printer on the color changes via the paper difference is not statistically provable. Edge frequency technique was introduced as an appropriate method for computing texture properties of papers. The texture difference computed by this method shows a suitable correlation with the color differences caused by changing the paper's texture; however, it depends on the printer's brand. Furthermore, there is a good correlation between the Edge frequency difference and the gamut volume variation for papers with different texture while the other parameters such as gloss and whiteness are the same. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 284–291, 2013     

Use of effect pigments for quality enhancement of offset printed specialty papers

Nowadays, effect pigments are widely used in many printing industries. The colorful effects produced by light scattering of these types of pigments add an additional value to the prints and enhances the overall quality of color appearance. The aim of this study was to investigate the quality enhancement of printed specialty papers with various effect pigments in combination with offset inks. Four different effect pigments were used (one luster pigment‐EP1, two interference pigments‐EP2, EP3, and one multicolor pigment‐EP4) as well as two types of paper substrates (film synthetic paper and wood‐free paper). The effect pigments were overprinted on dried CMYK offset prints on both paper substrates. The following analysis were performed: scanning electron microscopy analysis of effect pigment particles, contact angles of papers and offset prints, Fourier transform infrared spectrocopy (FTIR), principal components analysis (principal components analysis (PCA)), and flop index analysis of overprinted effect pigments, and paper and print gloss. The results of the experiment indicate that effect pigments behaved differently on different printing substrates. From the FTIR and PCA, it was found that the different composition of effect pigments differently influence the behavior of these particles on the final prints. Effect pigments overprinted on offset CMYK inks on both paper substrates enhance print gloss, except interference pigment EP2 on film synthetic paper. It was also found that the ink color has the most pronounced influence on flop index, followed by the papertype and the type of effect pigment. Higher flop index was obtained at wood‐free paper, especially by overprinted pigment EP2. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 168–176, 2013.     

A novel method for preparing nanoparticle‐coated additives used in polypropylene composites

A novel simultaneous, in situ milling and coating method carried out in a fluid energy mill (FEM) is applied for the first time to prepare nanoparticle‐coated CaCO₃ (CC) additives for polymer composite materials. Simply milled (without coating) CC particles and as‐received CC particles were used as references for comparison. The effects of the grinding pressure and the fraction of the nanoparticles on the size and flowability of CC particles were studied. The composites made with polypropylene (PP) and this specially prepared CC have higher elongation at break, elastic modulus, and impact strength, compared with the PP filled with uncoated CC. The thermal and thermo‐oxidative stabilities of PP are improved as well by introducing the milled and nanoparticle‐coated CC. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Antibacterial Nanocomposite of Poly(Lactic Acid) and ZnO Nanoparticles Stabilized with Poly(Vinyl Alcohol): Thermal and Morphological Characterization

The effect of polyvinyl alcohol (PVA) as a surface coating agent on the antibacterial and thermal properties of polylactic acid (PLA)/ZnO nanocomposites prepared by melt blending was investigated. The ZnO nanoparticles were coated and stabilized with PVA using a solvothermal method. Nanocomposites were prepared with different ZnO nanoparticle content: 1, 3 and 5 wt.%. Electron transmission microscopy and Fourier transform infrared spectroscopy showed the presence of a layer around the nanoparticles and the interaction between nanoparticles and PVA, respectively. DSC analysis revealed that the thermal properties of the nanocomposites were not affected by the coating of ZnO nanoparticles with PVA. The PLA/ZnO nanocomposites with coated nanoparticles presented better antibacterial activity than those containing uncoated nanoparticles.     

Effect of texture on color variation in inkjet‐printed woven textiles

Inkjet‐printed textiles are influenced by a wide range of parameters due to highly diverse textile structures and the resulting textures. The goal of this study is to understand the effect of texture on color appearance in inkjet‐printed woven textiles. Cotton‐woven samples were constructed with nine different weave structures. Each sample was digitally printed with identical squares of primary colors cyan, magenta, and yellow and secondary colors red, green, and blue. The amount of ink applied was controlled consistently with an image editing software. CIE L* values were calculated from the measured reflectance. 25 observers ranked the perceived texture and color lightness of each sample. Perceived visual texture and perceived color lightness scales were estimated from the rankings using the rank order method. The measured CIE L* values and the scale of perceived lightness were positively related for the primary and secondary colors. Instrumental measurements of the textile surface characteristics were positively related to the visual scale. Texture was demonstrated to cause a measurable effect on color results in inkjet printing, both using instrumental and perceptual measures. To investigate if the color differences were substantial enough to cause “out of tolerance” ratings in textiles based on common textile industry color acceptance procedures, color differences among the samples were calculated and compared to a reference sample. Results demonstrated that color variation due to texture was sufficient to lead to rejection of a printed color in comparison to a color specification. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 297–303, 2015     

Comparative Study of Silver Nanoparticles Coated and Uncoated NiO–Fe2O3–CaO–SiO2–P2O5 Ferromagnetic Bioactive Ceramics

Bioactive ferromagnetic ceramics of system xNiO–(3?x)Fe₂O₃–52CaO–30SiO₂–15P₂O₅, (x = 0, 3 mol%) have been prepared in the laboratory using sol–gel technique. Silver nanoparticles coating has been undertaken on the surface of synthesized samples. Comparative study of silver nanoparticles coated and uncoated samples has been undertaken with the help of transmission electron microscopy, X‐ray diffraction (XRD), degradation, drug delivery, hemolysis, antimicrobial, and cell culture studies. XRD patterns indicate the growth of hydroxyl apatite layer on the surface of coated as well as uncoated samples. Ferromagnetic properties of samples have been investigated with the help of vibrating sample magnetometer technique. Samples have shown good response as drug carriers under normal conditions as well as under the influence of magnetic field. Drug release mechanism and mesoporus nature of samples have been investigated with the help of Brunauer–Emmett–Teller technique. Nonreactivity of samples (coated and uncoated) with red blood cells and white blood cells show nontoxic nature of the samples. Coated samples have shown better antimicrobial properties against six different microorganisms, including some resistive strain like methicillin‐resistant Staphylococcus aureus with minimum inhibitory concentration of 0.05 mg/ml as compared to uncoated samples. It has been observed that samples also provide a healthy environment for the growth of MG 63 cell lines. It has been noticed that presence of silver nanoparticles on the surface of samples improve degradation and antimicrobial properties.     

A Study into the Influence of Paper Coatings on Paper Properties and Print Quality of Dye Sublimation Thermal Prints

The need for good quality paper for dye sublimation transfer printing has been reported previously as a principal requirement for the process. Pigmented coated papers have gained acceptance in the traditional paper printing industry, but, despite their importance, have inspired very few reports in literature about their application in heat transfer printing.

In the current work, we studied the influence of both clay and ground calcium carbonate (GCC) pigments and the incorporation of plastic pigment on the surface structure and mechanical properties of the coated paper used for transfer printing. The results showed that paper coating significantly reduced the surface roughness of the paper. The mechanical properties of the prepared coated paper, including tensile strength, stretch, tensile energy absorption (TEA), and burst index, were improved when coated compared to those of uncoated paper. The addition of plastic pigment to the coating mixture helped improve the paper's properties.

The optical density of the transfer-printed polyester fabric using the prepared coated paper was also compared with that of uncoated paper. It was shown that a slight increase in optical density was evident in the coated paper.

The possibility of producing a second polyester print from the exhaust paper was also investigated. Coated paper incorporating plastic pigment, in particular, showed higher optical density than did uncoated paper.

We found that coated paper based on clay, GCC, clay/plastic pigment, or GCC/plastic pigment consumed less dye paste than uncoated paper though producing printed fabric with higher optical density—especially in the second print.     

Accelerated weathering performance of Scots pine preimpregnated with copper‐based chemicals before varnish coating Part:1 coated with cellulosic and polyurethane varnishes

This study aimed to determine the effect of accelerated weathering on gloss, surface hardness and colour changes of Scots pine (Pinus sylvestris L.). Test samples were impregnated with Adolit KD‐5, Wolmanit CX‐8 and Celcure AC‐500 covered with cellulosic and polyurethane varnishes. The results showed that the values of surface hardness and gloss increased after accelerated weathering. While the surface hardness of Scots pine was increased for impregnated and polyurethane‐coated varnish, it decreased for impregnated and cellulosic varnish‐coated Scots pine after 1000 hours of accelerated weathering exposure. Copper‐based chemical impregnation and varnish coating developed the gloss of Scots pine specimens relative to the surface characteristics observed in single‐coated Scots pine specimens. While the most appropriate chemical was Celcure AC‐500 for surface hardness, it was Adolit KD‐5 for the gloss of Scots pine after 1000 hours of accelerated weathering exposure. Wood specimens impregnated prior to the application of varnish were more effective in stabilising the colour of Scots pine than Scots pine only coated with varnish. Polyurethane varnish‐treated Scots pine showed better colour stability for each partial and total accelerated weathering exposure period. The total colour changes were lowest for polyurethane varnish‐coated Scots pine impregnated with Celcure AC‐500 after 1000 hours of accelerated weathering exposure.     

A new method for colour measurements in graphic arts

This article presents a method for colour measurements directly on printed half‐tone multicoloured pictures. The article introduces the concept of colour impression. By this concept we mean the CMY or CMYK vector (colour vector), which lives in the three‐ or four‐dimensional space of printing inks. Two factors contribute to values of the vector components, namely, the percentage of the area covered by cyan, magenta, yellow, and black inks (tonal values) and ink densities. The colour vector expresses integrated information about the tonal values and ink densities. Values of the colour vector components increase if tonal values or ink densities rise and vice versa. If, for some primary colour, the ink density and tonal value do not change, the corresponding component of the colour vector remains constant. If some reference values of the colour vector components are set from a preprint, then, after an appropriate calibration, the colour vector directly shows how much the operator needs to raise or lower the cyan, magenta, yellow, and black ink densities in order to correct colours of the picture being measured. The values of the components are obtained by registering the RGB image from the measuring area and then transforming the set of registered RGB values to the triplet or quadruple of CMY or CMYK values, respectively. Algorithms based on artificial neural networks are used for performing the transformation. During the experimental investigations, we have found a good correlation between components of the colour vector and ink densities. © 1999 John Wiley & Sons, Inc. Col Res Appl, 24, 185–196, 1999     

Quantification and prediction of visually perceived specular gloss at three illumination/viewing geometries

In the present study, attempts were made to clarify the existence of a correlation between visually perceived and instrumentally measured specular gloss of a series of achromatic samples. To this end, seven achromatic physical scales of specular gloss each consisting of 10 or 11 samples were prepared using lithographically printed black, white, and five in between gray papers. The samples were visually assessed and subsequently quantified in terms of a visually uniform color constant lightness scale, by a panel of 14 observers in an especially designed unidirectional light compartment at three illumination/observation geometries, namely 20°/20°, 60°/60°, and 85°/85°. Four statistical parameters were utilized to determine the correlation between visually perceived and instrumentally measured specular gloss. The results show that the instrumental 60°/60° geometry is capable of efficiently quantifying the equivalent specular gloss as perceived by a human observer. Surprisingly, it was also possible to accurately predict the visually quantified specular gloss both at the 20° and the 85° geometries by the aid of applying special linear relationships derived from the instrumentally measured specular gloss of the 60° geometry.     

Surface characteristics of coating layers formed by coating pigments with different particle sizes and size distribution

The effects of coating color raw material variables were tested on absorbing and non-absorbing base materials. The particle size of the coating pigments was the main variable affecting the gloss of the non-absorbing base materials. Adding binders and increasing the drying temperature has a negative effect on the gloss development of both calendered and uncalendered coating layers. On calendered layers, coating layer films showed more gloss development than for coated papers, especially with coarse particles. Uncalendered calcium carbonate-coated papers have a higher PPS roughness than calendered clay-coated papers. The effectiveness of calendering, as described by “calenderability,” showed an increase in gloss with increasing number of nips, irrespective of size, and size distribution of pigment particles.