PAPER making! g! FROM THE PUBLISHERS OF PAPER TECHNOLOGY INTERNATIONAL ® Volume 11, Number 1, 2025
COATING “ Integrating barrier chemicals into coating systems for optimized white top testliner performance ”, Nuray Acar, Celil Atik & Duygu Bağbakar Orhan , Nordic Pulp & Paper Research Journal , online Feb. 2025, https://doi.org/10.1515/npprj-2024-0036. This investigation examined the development of a coating blend suitable for white top testliner paper to enhance its barrier properties and printability. The research focused on analyzing and elucidating the rheological and barrier properties crucial for the effective application of coating color. A double-coat application process was employed, with the pre-coating layer filling the rough surface profile and the top-coating layer improving the smoothness. Clay and calcium carbonate were used as pigments and latex as binder. Dispersant and thickener were also added. A barrier chemical was also incorporated in select formulations. The results indicated that the coating significantly modified the optical and barrier properties of the paper. The brightness, whiteness, and grease resistance increased, whereas the air permeability decreased. Barrier chemicals were particularly efficacious in reducing wettability and improving grease resistance. In conclusion, this study demonstrates that a well-designed coating strategy can enhance the functionality of recycled paper, rendering it a more viable option for packaging application. “Water -, Oil-, and Stain-Resistant Lignin-Based Degradable Waterborne Polyurethane for Paper Packaging Coating”, Haixu Wang, Ying-An Mai, Wenlian Qiu, Weifeng Liu, Dongjie Yang, Zhiqiang Fang & Xueqing Qiu, ACS Sustainable Chemistry & Engineering , Vol.13(3), 2025. Degradable paper-based packaging materials are promising alternatives to plastic packaging. However, the inherent limitations of paper, such as poor water and oil resistance, restrict its broader applications. It is essential to develop green and degradable coatings to compensate for the shortcomings of paper materials. In this study, we prepared a tough, hydrophobic, stain-resistant, and degradable lignin-based waterborne polyurethane (LWPU) for a paper packaging coating. LWPU emulsions with good stability were synthesized using low-molecular-weight lignin (LMWL) and polycaprolactone diol (PCL) as raw materials and poly(dimethylsiloxane) (PDMS) as a modifier. LWPU films exhibited excellent mechanical properties, with the optimal tensile strength of 40.3MPa and elongation at break of 1148%, hydrophobicity, antiaging properties, and UV shielding. The mechanical properties of the coated papers were significantly affected by the emulsion permeation and the type of paper substrate. The dense LWPU coating enhanced the barrier performance of the paper against water, oil, and gas. Incorporating PDMS segments into the coating further improved the hydrophobicity and stain resistance of the paper, allowing for easy removal of common stains. Moreover, the coating can be completely removed from the paper using solvent-dissolving and chemical degradation methods, which is advantageous for paper recycling. This work provides a reference for the industrial application of LWPU emulsions as green paper coatings. ENERGY “ Assessing energy use, carbon emissions and its driving factors for the pulp and paper industry in China ”, Lingbo Kong, Liang Chen & Wolfgang Eichhammer, Journal of Cleaner Production , Vol.491, 1 Feb. 2025, 144832. As one of the main energy sources in China's pulp and paper industry (CPPI), biomass fuel is worth attention for its carbon- neutral characteristic. This article assessed the energy use and carbon emissions of CPPI, with an emphasis on biomass fuel use. The driving factors of carbon emissions were also explored with the Logarithmic Mean Divisa Index (LMDI) method. During the investigated period (2005 – 2021), total final energy use varied from 1050 to 1624PJ, of which biomass fuels account for 15.9 – 25.5%. Energy intensity declined from 18.8 to 12.8GJ/t. Although the energy mix is shifting toward less coal and more biomass and electricity use, coal still
Technical Abstracts
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