Leipzig University of Applied Sciences conducted a study into the present role of gravure and found respondents continue to hail the technology’s reusability credentials.
Gravure printing offers great potential for the circular economy: its major ecological advantages are the reusability of the printing cylinder and closed material cycles which enhance the sustainability of the gravure process and give it an edge compared with other processes.” These are the conclusions of a study on the sustainability of the gravure process carried out by Leipzig University of Applied Sciences (HTWK). The study was conducted in the first half of 2022 and presented by Prof Lutz Engisch from the University at ERA’s recent Annual & Packaging/Decorative Conference in Baveno, Italy. The study covered the whole gravure printing workflow, including upstream and downstream processes, as well as recycling and de-inking. According to the respondents, the strongest advantage of gravure printing is the reusability of the base cylinder.
Its high stability and consistency to print even very long runs in constant high quality also counts as gravure’s major advantage in respect of sustainability. The study, which shows that the market demands these large orders with run lengths of more than 800,000m, has proven this is a relevant factor. Another advantage concerning the sustainability of gravure is the recovery of the materials used during the plating processes such as copper and chromium. And further improvements are seen in the recovery of solvents, the use of water-based inks and the reduction of make-ready waste through automation.
The electrolysis process of chromium trioxide, which is used in the plating to guarantee the hardness and long lifetime of the cylinder, is perceived as the most serious challenge for gravure, as the industrial use of chromium trioxide needs authorisation by the EU Commission according to the EU rule Reach (Registration, Evaluation, Authorisation of Chemicals). Even though the EU Commission has granted authorisation for the gravure industry, and an extension beyond 2024 can be expected, the industry is developing alternatives or replacing traditional copper and chromium layers with a plastic layer, which will increase sustainability.
In addition to the questionnaire and interviews, first approaches for a life cycle assessment (LCA) were carried out. In this context, the first challenges and limits could already be identified: general statements are not possible. Due to the wide range of parameters, a general holistic comparison of different printing processes would be very difficult to perform. Product-dependent case-by-case decisions, supported by comparative LCAs, could help identify the most environmentally friendly printing process for the respective print job.
The online questionnaire was conducted from February 14 to Jun 1 and addressed more than 116 people. It included questions on all life stages of the rotogravure printing workflow and includes upstream and downstream processes, for example cylinder engraving and transportation as well as recycling and deinking. Based on the defined role in the gravure printing industry, the survey contained a certain selection of questions, specifically addressed to these stakeholders. Respondents were very concerned with sustainability, with 43% indicating they were very familiar and 48% indicating they were moderately familiar with the issue of ecological sustainability within the gravure industry.
The analysis of the largest orders showed that run lengths up to 800,000m still exist. Mono film material with a thickness below 25μm is the most frequently used substrate. The reusability of the base cylinder is perceived as the strongest advantage of gravure printing.
Further strong improvements concerning the sustainability of the process were seen in the use of and the reduction of emissions of hazardous chemicals. Within the respondents, the electrolysis process of chromium trioxide (CrVI) is perceived as the strongest challenge for gravure printing. Approaches for further improving the sustainability in the future were seen in recovering solvent, using lower ink film to save ink, the substitution of CrVI and reducing make-ready waste (for example, through automation).