Naslov
Determination of fountain solution's functionality

Autori
Cigula, Tomislav ; Mahović Poljaček, Sanja ; Tomašegović, Tamara ; Fuchs-Godec, Regina

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings of 8th international symposium on graphic engineering and design / Živko Pavlović - Novi Sad, 2016, 71-76

ISBN
978-86-78928-67-3

Skup
GRID 2016 - 8th international symposium on graphic engineering and design

Mjesto i datum
Novi Sad, Srbija, 03.11.2016. - 04.11.2016

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
lithography; fountain solution; printability testing; surface tension; contact angle

Sažetak
Lithography is a printing technique in which selective adsorption of printing ink on the printing plate is achieved by opposite surface properties of printing and nonprinting areas. It is a two liquids technique where beside printing ink fountain solution must be used to enable nonprinting areas to repel the printing ink. Fountain solution is composed of water and some additives including buffer and surface active substances. The buffer solution must keep the fountain solution in defined pH value range (4.5 – 5.5) as lower or higher pH value would significantly influence printing process and/or stability of the printing plate. Surface active substances are added in order to decrease surface tension of the solution and enable coverage of the nonprinting areas on a printing plate with lower amount of the solution. Most common surface active substance used in lithography is propan-2-ol (isopropyl alcohol, IPA), but as it has bad influence on ecology and human health, in recent years fountain solutions with lower IPA amount or even without IPA (alcohol free fountain solution) have been developed. The aim of this paper is to determine functionality of the fountain solutions prepared with various amounts of IPA. For the purpose of this research, two sets of the fountain solutions, FS1 and FS2, were prepared and characterized by measuring pH value, electrical conductivity and surface tension. In addition, the Pruefbau MZ II Multipurpose Printability Testing System was used to determine amount of the fountain solution needed to cover nonprinting areas on the printing plate and disable adsorption of the printing ink. To detect chemical wear of the printing plate by the fountain solution, potentiodynamic polarization measurements were performed. Results showed that solutions FS1 have higher pH value and higher electrical conductivity than solutions FS2.In both sets it is visible trend of increasing pH value and decreasing electrical conductivity by addition of IPA. The surface tension is lowest by FS1 in which 4 %vol of IPA is added, even more the whole FS1 set has lower surface tension than the lowest surface tension measured in set FS2 (measured in sample with 12.5 %vol of IPA). The contact angle values were in good correlation to the surface tension values (calculated Spearman’s correlation coefficient was 1 for FS1 and 0.9 for FS2). In simulated printing process, better spreading of the solution on the printing plate surface was achieved using FS2, where for almost all solution samples even 5 µl were enough to reach optimal area coverage. The electrochemical measurements showed that there is no corrosion for all investigated fountain solution samples. From this research one could conclude that investigated samples do not cause corrosion of the aluminum based lithographic printing plates. The addition of the IPA causes reduction of the surface tension that leads to lower contact angle measured when applying fountain solution onto the nonprinting areas of the lithographic printing plate. The simulation of the printing process using the Pruefbau MZ II Multipurpose Printability Testing System could be used as a tool in defining amount of fountain solution needed to disable adsorption of the printing ink, but the process should be fine tuned.

Izvorni jezik
Engleski

Znanstvena područja
Grafička tehnologija

POVEZANOST RADA