In order to apply methylene blue (MB) dispersed in paper as oxygen indicators, reflectance spectra were studied for MB dispersed in papers. From the spectral characteristics of the papers dipped in neutral MB solutions, an increase in the monomeric MB in comparison with dimeric MB was observed during the drying process. The increase in the monomeric MB was attributed to the adsorption of MB to the pore surfaces of cellulose during diffusion and drying of MB solutions. The N-demethylation of MB in basic solutions occurred by the effect of hydroxide ions and MB changed to azure C after about 1 hour. On the other hand, the N-demethylation reaction in the papers dipped in basic MB solutions proceeded more slowly, resulting in the formation of azure C after about a month. Oxygen indicators were prepared by dipping papers in solutions containing MB, glucose, and sodium hydroxide. The blue color of oxygen indicators due to MB disappeared in deoxygenated condition. When the deoxygenated condition was broken after 103 days, the sample revealed a blue color again after 5 min and the same spectrum as that of MB. It was considered that the N-demethylation reaction of MB was suppressed in a leucomethyleneblue structure.
A viscoelasticity measurement device for measuring complex moduli of coatings films during cure process was applied to multi-layer systems. The device is equipped with a pendulum and the fulcrum of it is a knife edge as a probe for coatings moduli. Theoretical consideration predicts that the contribution of the upper layer to measurement is dominant so that the modulus measurement deviation by assuming single layer of clear-coat will be 7% in a typical case. Three clear-coats with different curing chemistry were laminated on common waterborne base-coat in 2C1B process and cure rate constants were examined. As waterborne base-coat contains amine, curing measurements were also applied to single layers of amine-added clear-coats and neat clear-coats. The curing rate of acid-epoxy clear-coat was increased in 2C1B and amine-added single layer, whereas the curing rate of melamine curing clear-coat was decreased. No effect was observed in the case of isocyanate curing clear-coat. Accordingly, it is possible to quantitatively discuss the influence of amine migration from base-coat on clearcoat curing.
High-Quality/High-Definition Ink System has high accuracy and excellent printing stability, which enables printing of 100 μm thin lines with ink flow-out width within 116 μm. This ink system consists of 3 components: ink, printing materials and equipment (mesh technology, plate making technology and printing machine technology) and printing technology, which with a single ink can form various images including solid images, but not fine patterns such as dots.
High-Quality/High-Definition Ink has characteristics such as providing high viscosity and thixotropy, faithful reproduction of the plate pattern and no spreading of ink flow-out.
The present article introduces the characteristics of High-Quality/High-Definition Ink and gives examples of printing realized by this system.
The advantages and disadvantages and current studies in the field of the water-based flexographic printing systems for flexible packaging are discussed. Common ingredients for water-based flexo inks for flexible packaging are introduced from the viewpoint of selection, features and aptitude; General issues for flexographic printing with water-based inks are examined from the standpoint of an ink manufacturer.
The domestic printing market has tended to contract in recent years due to the diversification of media owing to the spread of smartphones and the like. However UV curing ink, which has strong resistance characteristics and dries instantly upon irradiation with ultraviolet light, is expanding in various applications.
As contributions towards environmental conservation, such as energy saving and CO2 reduction, we have developed UV light emitting diodes (LED-UV), ozone-less type UV lamps, and inks which are cured with these light sources. For applications involving thin paper the replacement of conventional oil-based inks by high sensitivity inks has been actively conducted.
At Drupa 2016, LED-UV and high sensitivity UV showed signs of becoming mainstream technologies for offset printing.
In this paper, we describe the fundamental knowledge of highly sensitive UV ink and its characteristics and future prospects.
Outline of regulation on VOC control and compliance of Japanese paint industry in reducing VOC emission from paint applications are described in this report. Estimated VOC emission during paint applications has sharply dropped by 49.5% from 535 thousand tons in 2000 to 270 thousand tons in 2015 thanks to various efforts made by all related parties including paint users.
Paint applications remain however one of the biggest VOC emission sources, so a sustained effort will be needed to achieve further VOC reduction.