Nemanja Kašiković

The characterization of microcapsules printed by screen printing and coating technology

The graphic industry is one of the first that began to utilize microcapsules, which are nowadays used in various fields of applications such as: medicine, pharmacy, agriculture, construction industry, chemical industry, food industry, biotechnology, cosmetic industry, photography, electronics, textile and printing industry (Boh et al., 1999; Arshady & Boh, 2003; Boh, 2007; Poncelet & Boh, 2008). Microcapsules are tiny spheres that usually consist of two parts: the core and the shell (Gosh, 2000). Microencapsulation enables the core material to reach the “target” areas without getting affected by the surroundings, while the microcapsule microscopic size enables the consumption of the very small active agent quantity (Gosh, 2000; Dubey et al., 2009; McShane & Ritter, 2010; Microtek Laboratories Inc., 2015). One of the simplest and the most frequently used encapsulation method in the graphic industry is “in situ” polymerization, which provides high active agent loadings and smoothly shaped microcapsules with good mechanical properties (Kuković & Knez, 1998; Gosh, 2000; Nelson, 2001; Starešinič, Šumiga & Boh, 2011; Ocepek et al., 2012). Microcapsules used in printing applications can be activated by the use of different mechanisms, which are mainly based on external pressure, abrasion and heat or light activation (Gosh, 2000; Nelson, 2001; Boh & Šumiga, 2008; Sensor Products Inc., 2015). Rastko Milošević1, Nemanja Kašiković1, Tomislav Cigula2, Urška Stanković Elesini3 and Raša Urbas3

15 – Screen Printing

Screen printing is a stencil-based process; it consists of closed nonimage areas and open-image areas. It is based on the principle of squeezing the ink through open areas of the mesh onto the printing substrate. Of all printing techniques, screen printing has the widest range of applications. Paper, textile, polymers, glass, or any other solid material can be printed using screen printing. Different characteristics of these materials demand different ink types to be used, but the principle remains the same. In this chapter, the fundamentals of screen printing, stencil/plate making, printing process, and a short overview of screen printing industry are presented.

Evaluation of effective models of offset CTP plate aluminium oxide surface roughness characterisation

In this study, three different approaches for characterisation of printing plates non-printing elements surface structure and roughness were compared: stylus profilometric method, AFM, method and software (indirect), SEM image-based profilometry. The comparison was made to evaluate the possibility of utilising the different methods for characterisation of CTP offset printing plate surface roughness. The direct profilometric measurements involved the use of stylus profilometer visual analysis were made using AFM device and for the indirect approach, the Gwyddion software, for analysis of single and stereo SEM images and calculation of standard profilometric parameters, was used. The results of this study demonstrate that it is possible to obtain profilometric parameters from the analysis of AFM and SEM micrographs with appropriately calibrated grey scale intensity distribution and that the values of the parameters are comparable to those obtained by contact stylus profilometry. The results of this comparative study indicate that profilometric 2D direct stylus method is more applicable when larger areas tend to be measured, while the indirect image-based 3D profilometry is a valuable and efficient tool for characterisation of various surfaces topographies on micron scale sample areas.

Washing treatment impact on print quality of screen printed knitted fabrics

The surface of textile materials is highly textured, commonly in non-uniform ways. Because of this texture effect, textile surface appears rougher and more porous than other printing substrates, which can cause excessive ink penetration during printing process. Next, washing process is very important factor because it influences ink characteristics on printed samples as well as structural changes of the textile substrate. The aim of this paper is to determine the influences of washing process and different mesh tread count used for printing on print quality. This will be obtained by using spectrophotometric analysis, and GLCM image processing method for print mottle estimation. The results of this research show that increasing number of washing processes leads to higher color differences reproduction color in comparison to printed materials before washing. It also shows that textile surface texture has a great influence on print mottle as well as that number of washing treatment series can generate variations of solid-tone print uniformity.

Color appearance of textile materials applied to various geometrical shapes

The color of textile products is mainly controlled during the material production process, e.g. dyeing or printing, using color management protocols. Little attention has been given to researching the color appearance of the textile material applied to final products, where textile material is applied to a shape. The results are reported of research into the color appearance of textile materials of varying material characteristics, color, and geometrical shape to which they are applied. The main focus was on determining color differences between real textile material color and the perceived one. Materials were characterized by their composition, fabric structure, fiber type, thread count, surface characteristics, and glossiness. Samples of red, blue, orange, violet, and green color were chosen as the most frequently used colors in real application. Textile materials were applied on three differently shaped objects (flat surface, cube, and cylinder). The object color was determined by objective instrumental measurements as well as subjective judgment. A specially constructed light chamber was used to ensure constant experimental conditions. Data were subjected to statistical analysis in order to determine differences of each CIE Lch color coordinate. Results indicate significant effects of objects shape on color appearance.