Spectroscopic Stability Studies of Pressure Sensitive Labels Facestock Made from Recycled Post-Consumer Waste and Agro-Industrial By-Products

To support circular economy and sustainability, the use of synthetic polymers should be minimized due to their excessive accumulation in the environment and low biodegradation rate which leads to a global waste problem. Thus, the quota of natural resources should be increased, as well as the use of agriculture and industrial waste or by-products as raw materials in industrial processes. Agro-industrial wastes were found to have high cellulose fiber potential which makes them an excellent resource for paper production. This study investigates the influence of artificial aging test on the stability of commercially available fiber based self-adhesive pressure sensitive labels (PSL), in which the facestock is made of 15% agro-industrial byproducts, 40% post-consumer recycled paper and 45% virgin wood pulp and compared to ones made of biobased polyethylene. The results showed that optical brighteners are present in the composition of fiber based PSL. Moreover, the fluorescence and UV-Visible spectroscopy results indicated that by the action of UV irradiation and temperature. The oxidation of cellulose was not found by FTIR spectroscopy, indicating its high stability.

Producing Direct Food Packaging Using Deinked Office Paper Grades—Deinkability and Food Contact Suitability Evaluation

Paper recycling is the most eco-efficient waste management option, since the use of recycled fibers reduces the need for virgin wood fiber and lowers energy consumption, and hence has a positive effect on the environment. The use of recycled paper is by far the highest in the packaging industry. In food packaging production, recycled paper is often favored over paper and board made from virgin fibers. However, due to the possible hazardous chemicals that can be found in recycled paper, there is a dilemma of how to overcome food safety issues while making food packaging more circular. The objective of the study was to determine if deinked office paper grades could be used as an alternative fiber source in the production of food packaging white top linerboards. For that purpose, three different types of digitally printed papers were submitted to a chemical deinking flotation in laboratory conditions, and the handsheets formed after each recycling trial were tested on the suitability for direct food contact. Evaluation of deinkability for each group of recycled prints was performed, as well. Deinkability was evaluated by calculating the flotation yield, pulp’s brightness and whiteness increase, ink elimination factor, determination of residual ink area, as well as ash content elimination. Food safety evaluation was performed by determining the content of heavy metals (Cd, Pb, Hg, and Cr VI), primary aromatic amines, diisopropylnaphthalenes (DIPN), phthalates, and polychlorinated biphenyls (PCB) from aqueous or organic solvent extracts of recycled paper pulp. The fastness of the fluorescent whitening agents was determined, as well. Of all evaluated deinking flotation efficiency parameters, only flotation yield and ash reduction by flotation were positively assessed. High content of residual ink particles detected after the flotation stage indicates that the flotation was not a successful method for the elimination of disintegrated ink particles, which was also confirmed by deficient results of ink elimination measurements and whiteness increase. Flotation proved to be the least efficient in the recycling of inkjet prints, where the lowest ink elimination, whiteness, and brightness values were achieved. As far as food safety assessment of deinked pulp is concerned, all tested deinked handsheets were found suitable to be used in direct contact with foods.

Issues of long-term durability of paper – Labest Papier

In the project “Labest Papier – Langzeitbeständigkeit von Papier” (Labest Paper – Long-term durability of paper), the suitability of paper to serve as a permanently undamaged information carrier for at least 500 years is to be assessed by the Department of Paper Manufacturing and Mechanical Process Engineering (PMV) for the Federal Office for the Safety of Nuclear Waste Disposal (BASE). The ageing mechanisms of paper are known, as are countermeasures. This leads to standards and recommendations for the use of paper for documents. DIN EN ISO 9706 (2010) is the main proponent of the direction that longevity can be ensured solely via the composition of the paper and the initial situation at the beginning of ageing. DIN 6738 (2007), on the other hand, takes as its basis the approach of assessing the physical ageing of the paper based on artificial ageing and the strength losses observed in the process. Other standards vary the approaches somewhat or mix them in part, for which the lecture presents a comparison table. The usability of a document depends on two essential factors. Firstly, the residual strength after an ageing process must be high enough for the document to be usable. Secondly, the information written on it must still be legible or at least recognisable. The limits of the possibilities for dealing with damage that has already occurred are almost only set by complete destruction. Otherwise, forensic means can restore the information in a document, at least in part, with the appropriate investment of time and money. The lecture provides examples, such as the reprocessing of shredded Stasi files. Even the loss of knowledge of writing and language need not be a final obstacle, as the decipherment of hieroglyphics proves. The costs of measures to deal with damage depend individually on the condition of the documents and on the objectives in dealing with the damage. Prevention is an effective means of avoiding damage and costs in the first place. Paper is an information carrier well known for over 2000 years and has already proven its suitability for storing long-term information. Despite the fact that an intactness in the sense of being completely untouched is never given, paper has the advantage of a long migration time and that no reading or decoding device is necessary compared to modern information storage media, such as digital media or microfilm. Which grade of paper will ultimately meet the demands, however, depends on the overall consideration of the availability of the grade, the expected damage and the possibilities and costs of handling it. There is still a need for research, especially with respect to the assessment of the effect of printing inks and auxiliaries used in paper production on the longevity as well as the classification of recycled paper. An extensive measurement program is investigating this during the current project. After the project is accomplished, BASE will be able to decide in which way the already existing types of papers including marking can be preserved for as long as necessary and how the state-of-the-art optimised system “paper ink” must be prepared to ensure long-term durability. The paper is based on two working stage reports, AP1 (Schaffrath, 2020) and AP2 (Schaffrath, 2021).

Assessment of moisture and mould of hempcrete and straw panels

At present buildings contribute a third of total greenhouse gas emissions. There is a need for sustainable solutions and natural materials, which offer low-embodied energy and their low impact has a promising potential as construction alternatives. Hempcrete is a lightweight insulation material, which provides natural, airtight, and vapor-permeable insulation. Straw panels are also natural construction materials and they consist of extruded wheat straw and are surrounded with recycled paper on all sides. There are some risks, which can be associated with the use of such materials - infestation, biological degradation, presence of moisture, and structural degradation. The aim of the study is to determine the critical moisture level and mould resistance of hempcrete and straw panels. The results of this study are valuable to both scientists and structural engineers.

Application of spruce wood flour as a cellulosic-based wood additive for recycled paper applications— A pilot paper machine study

This study gives a first insight into the use of wood flour as a plant-based and cellulosic-based alter-native additive for newsprint and paperboard production using 100% recycled fibers as a raw material. The study compares four varieties of a spruce wood flour product serving as cellulosic-based additives at addition rates of 2%, 4%, and 6% during operation of a 12-in. laboratory pilot paper machine. Strength properties of the produced newsprint and linerboard products were analyzed. Results suggested that spruce wood flour as a cellulosic-based additive represents a promising approach for improving physical properties of paper and linerboard products made from 100% recycled fiber content. This study shows that wood flour pretreated with a plant-based polysaccharide and untreated spruce wood flour product with a particle size range of 20 μm to 40 μm and 40 μm to 70 μm can increase the bulk and tensile properties in newsprint and linerboard applications.

COD removal, decolorization, and energy consumption of electrocoagulation as a wastewater treatment process

The efficiency of color and COD removal in wastewater treatment is one of the essential factors. High color removal can encourage the reuse of wastewater as raw material in the recycled paper industry. Electrocoagulation (EC) process is effective pollutant removal in wastewater due to the adsorption, coagulation, and flotation. In this study, recycled paper industrial wastewater was used; this type of waste has a high content of disturbing pollutants, and treatment with electrocoagulation has not been widely carried out for this type of waste. EC treatment has a relatively high level of effectiveness to remove these pollutants; the influential factors studied include initial pH, applied current, supporting electrolyte, and processing time on a laboratory scale. The degradation of color, COD, and energy used was also evaluated. The best color removal was obtained as 100% at 80 minutes of process, and a COD concentration is 147 mg/L, and the energy used is 13.56 kWh/L.