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Nowadays, the paper industry is facing challenges in providing its main raw material – wood. Deforestation and the lack of reliable sources, as one concern, and transport issues as another, contribute to the rising research into new materials that can be used to partly replace wood as the main source of cellulose fibres needed for paper production. The latest research indicates that cereal straw has great potential as an additional source of cellulose fibres, due to its renewable nature and low cost. Paper substrates with added cereal straw pulp are mainly used for the secondary packaging purposes, and therefore they must show high mechanical resistance. Secondary packaging, almost always, contains printed information about the product that is exposed to various external conditions, and it is important that the print remains unchanged during transport and handling of the packaging. This research focuses on comparison of the mechanical resistance (or rub stability) of prints on papers to which straw pulp of three cereals abundant in Croatia have been added: wheat, barley, and triticale. Prints were made using UV curable inks and four different printing techniques (offset, gravure, flexographic, and digital printing). Mechanical resistance was determined by conducting the rub resistance tests and calculating the Euclidean colour difference based on measured colorimetric values of the prints before and after the tests. A comparison of the results was made to establish the best suited combination of printing technique and paper substrate containing cereal straw pulp that ensures the highest mechanical resistance of the print. |
