Description of Thermochromic Offset Prints Morphologies Depending on Printing Substrate

Rožić, Mirela; Šegota, Nikola; Vukoje, Marina; Kulčar, Rahela; Šegota, Suzana

doi:10.3390/app10228095

Cited by 17 publications

(12 citation statements)

References 55 publications

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“…All measurements of the contact angles were performed at 0.4 s after the drop had touched the measured substrate. Surface tension of the referent liquids and their contact angles were used to calculate SFE (γ) and its dispersive (γ d ) and polar (γ p ) components on all samples by using the Owens, Wendt, Rabel, and Kaelble (OWRK) method [34][35][36][37][38]. Total, dispersive, and polar surface tension components of probe liquids expressed in mJ/m 2 were respectively: diiodomethane-50.8, 50.8, and 0; glycerol-64.0, 34.0, and 30.0; and water-72.8, 21.8, and 51.0.…”

Section: Characterization Methodsmentioning

confidence: 99%

Properties and Colorimetric Performance of Screen-Printed Thermochromic/UV-Visible Fluorescent Hybrid Ink Systems

et al. 2021

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In the present research, properties and performance of special effect printing inks were observed with the aim of obtaining a printed product with dual functional properties. Thermochromic liquid crystal-based printing ink (TLC) and UV-visible (daylight invisible) fluorescent inks (UVF), pure and as hybrid ink systems, were printed using a screen-printing technique on two types of uncoated paper substrates. Characterization of the paper substrates was performed, as well as detailed analysis of printed layers. Thickness, surface roughness, surface free energy, and adhesion parameters of printed layers were analysed. Spectral reflectance of pure UVF and TLC printing inks, as well as the spectral reflectance of the proposed hybrid ink systems were measured. The thermochromic effect of the TLC ink and hybrid systems was analysed. Microscopy was used to display the visual colour play effect and the effect of the fluorescence. Results of the measurements showed high compatibility of used materials in the proposed hybrid ink systems. Since the effect of luminescence and the colour play effect in the hybrid systems were preserved, it can be concluded that TLC/UVF hybrid ink systems can find their application in the development of functional packaging and in all other applications with special requirements for temperature monitoring and hidden information for different products.

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Section: Characterization Methodsmentioning

confidence: 99%

Properties and Colorimetric Performance of Screen-Printed Thermochromic/UV-Visible Fluorescent Hybrid Ink Systems

et al. 2021

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“…The darkest print is on recycled paper due to the highest concentration of blue colored microcapsules. (Rožić et al, 2020) itself cannot cause such a large b* value of the print on the bulky paper at the end of heating. It is possible that some component from the ink was adsorbed on the surface of the bulky paper in a larger amount than on the other substrates, which causes a positive b* value.…”

Section: Hysteresismentioning

confidence: 97%

“…The SEM images show that the entire surface of the recycled and bulky paper has been used as far as microcapsules are concerned, while the synthetic paper has not. Synthetic paper contains 44.5 wt% of calcium carbonate (Rožić et al, 2020). Ion-dipole interactions are stronger compared to hydrogens and dipole-dipole.…”

Section: Hysteresismentioning

confidence: 99%

The effect of carbonyl components of printing substrates on the durability of UV thermochromic prints

Rožić,

Cigula,

Miljanić

2023

J. Graph. Eng. Des.

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Special effects on a printed product can increase consumer’s interest in a product and therefore lead to higher revenues in consumer industries. For that purpose, graphic industry introduced various technologies and materials that would have such an effect and enhance consumer-goods interaction. One of those solutions is thermochromic printing. Although bringing added value, thermochromic inks have some challenges in application due to their higher sensitivity, especially when exposed to UV light. Therefore, the goal of this work is to determine whether amount of the UV radiation during curing of UV thermochromic prints, as well as exposure after printing would degrade the thermochromic print on various substrates. UV thermochromic prints were made on three different paper printing substrates using the screen printing method and dried in a laboratory controlled unit. Synthetic paper, recycled paper containing 100 % recycled cellulose fibers and bulky voluminous paper were used as printing substrates. During the UV curing of the ink, no photooxidation of the prints occurred. Additional exposure of the prints to UV radiation (after the ink has hardened) leads to their photooxidative degradation, i.e., a change in the initial color. The obtained colour difference (ΔE) is increasing with the increase of the irradiation amount. The highest colour difference is on the synthetic paper while prints on two other substrates are more resistant to UV light. A print on synthetic paper photooxidizes the fastest due to the presence of most carbonyl groups in it. Generated free radicals promote the instability of prints on synthetic paper. Research has proven that when using synthetic paper or substrates with similar characteristics, care should be taken to accurately determine the amount of UV energy required for curing in order to prevent photodegradation of the ink. The results also show that to explain any degradation of prints, the chemical components of the paper needs to be taken into account, which is rarely done.

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“…Contact angles and surface energy were calculated by ADVANCE software (KRÜSS GmbH, Hamburg, Germany) fitting the drop profiles to the Young-Laplace equation. Surface energy (SFE) was calculated by the software following the Owens-Wendt-Rabel-Kaelble (OWRK) equation (Equation ( 1)) [25].…”

Section: Analysis Of Wettability and Surface Energy Changes In Relati...mentioning

confidence: 99%

Investigating Potential Effects of Ultra-Short Laser-Textured Porous Poly-ε-Caprolactone Scaffolds on Bacterial Adhesion and Bone Cell Metabolism

et al. 2022

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Developing antimicrobial surfaces that combat implant-associated infections while promoting host cell response is a key strategy for improving current therapies for orthopaedic injuries. In this paper, we present the application of ultra-short laser irradiation for patterning the surface of a 3D biodegradable synthetic polymer in order to affect the adhesion and proliferation of bone cells and reject bacterial cells. The surfaces of 3D-printed polycaprolactone (PCL) scaffolds were processed with a femtosecond laser (λ = 800 nm; τ = 130 fs) for the production of patterns resembling microchannels or microprotrusions. MG63 osteoblastic cells, as well as S. aureus and E. coli, were cultured on fs-laser-treated samples. Their attachment, proliferation, and metabolic activity were monitored via colorimetric assays and scanning electron microscopy. The microchannels improved the wettability, stimulating the attachment, spreading, and proliferation of osteoblastic cells. The same topography induced cell-pattern orientation and promoted the expression of alkaline phosphatase in cells growing in an osteogenic medium. The microchannels exerted an inhibitory effect on S. aureus as after 48 h cells appeared shrunk and disrupted. In comparison, E. coli formed an abundant biofilm over both the laser-treated and control samples; however, the film was dense and adhesive on the control PCL but unattached over the microchannels.

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Description of Thermochromic Offset Prints Morphologies Depending on Printing Substrate

Cited by 17 publications

References 55 publications

Properties and Colorimetric Performance of Screen-Printed Thermochromic/UV-Visible Fluorescent Hybrid Ink Systems

Properties and Colorimetric Performance of Screen-Printed Thermochromic/UV-Visible Fluorescent Hybrid Ink Systems

The effect of carbonyl components of printing substrates on the durability of UV thermochromic prints

Investigating Potential Effects of Ultra-Short Laser-Textured Porous Poly-ε-Caprolactone Scaffolds on Bacterial Adhesion and Bone Cell Metabolism

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