The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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New Business Opportunities for Printed Media: Coated Paper for Coldset Printing

Elina Kalela

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Forest Products Technology for public examination and debate in Auditorium E (Main building) at Helsinki University of Technology (Espoo, Finland) on the 25th of November, 2005, at 12 noon.

Overview in PDF format (ISBN 951-22-7900-2)   [1869 KB]
Dissertation is also available in print (ISBN 951-22-7899-5)

Abstract

The target of this study was to identify the most important variables affecting the internal product integrity in the case of coated grades for coldset web offset printing. Internal product integrity was experimentally identified to mean in this work printing runnability and visual print quality. Printing runnability was experimentally defined to mean build-up formation tendency on the surface of the common impression cylinder (CIC) at satellite type coldset printing machines. Visual print quality was defined to mean set-off, print-through, contrast, dot-gain, evenness of printed surface and reproducibility of colors.

The objectives of this study had significant commercial value and therefore the entire experimental part was carried out on industrial scale. This experimental set-up was aiming to speed-up the application of potential findings to industrial scale and to facilitate the exploitation of the results since the time consuming and risky step of scaling the laboratory results to industrial scale could be skipped over. The experimental part of this work consists of four parts: Pilot coating of industrial base papers, printing tests in commercial coldset printing process, comparison of print quality potential of different printing methods (coldset, waterless coldset and heatset) and laboratory analyses of base paper, unprinted and printed coldset samples. Laboratory analyses included structural tests, absorption tests, various microscopic methods, permeability tests, confocal Raman analyses and various printability tests.

The results of the print quality testing showed that matt LWC printed in coldset reaches such a qualitative level that it allows the printer to exceed the technical obstacles by which the new business models are often confronted. It was further identified that coating pigments and base paper properties have influence on internal product integrity of matt LWC paper in coldset printing. The influence of coating pigments as a single variable in the fine tuning of the internal product integrity was smaller than expected. The influence of coating pigments on the internal product integrity is most likely depending on the base paper properties. A natural area for future studies would be to identify the most important paper technological variables influencing the internal product integrity via base paper properties. Latex properties as single variables did not have clear influence on internal product integrity. Latex coverage had some influence to the internal product integrity. Therefore, experimental designs profiting latex properties as multivariable parameters could bring new knowledge to the fine tuning of the internal product integrity.

Printing paper manufacturers should shift the technical testing of product prototypes to industrial scale from laboratory scale. Creation of a new product in printing paper industry should approach the standard concurrent engineering processes, where new product is widely tested in industrial scale after the innovation phase, but before market launch.

This thesis consists of an overview and of the following 5 publications:

  1. Kalela, E., Assessment of technical tools for product development of matt LWC grades for CSWO printing, PAPTAC 91st Annual Conference Proceedings, February 7-10, 2005, Montreal, Canada, p. D619-D624. © 2005 Pulp and Paper Technical Association of Canada (PAPTAC). By permission.
  2. Kalela, E., Desjumaux, D., The influence of coating binders and base paper to printed paper attributes and runnability of matt LWC grades in cold set web offset printing, PITA Coating Conference Proceedings, March 15-16, 2005, Bradford, UK, p. 123-131. © 2005 Paper Industry Technical Association (PITA). By permission.
  3. Kalela, E., Can better printing surface enhance the CSWO printing industry to adapt to the change of its business environment, PulPaper 2004 Coating Conference, June 1-3, 2004, Helsinki, Finland, p. 23-31. © 2004 Finnish Paper Engineers' Association. By permission.
  4. Kalela, E., Producing different surface structures for LWC matt paper for CSWO printing, Paper Technology, 44 (5), June 2003, p. 49-56. © 2003 Paper Industry Technical Association (PITA). By permission.
  5. Kalela, E., Ridgway, C. J., Gane, P. A. C., Ink-coating adhesion: Factors affecting deposits on the CIC in "satellite" type CSWO presses when using VAC papers, Journal of Graphic Technology, 1 (2003): 1, p. 49-58.

Keywords: coldset web offset printing, coated paper, product differentiation, product integrity, base paper, latex, paper structure, build-up

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© 2005 Helsinki University of Technology

Last update 2011-05-26