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Journal articles
Influence of base sheet properties on barrier coating performance, TAPPI Journal November 2025
ABSTRACT: Paper packaging offers a sustainable alternative to standard plastic-based materials, particularly for food and beverage applications. With reduced fiber treatment options like fluorochemicals, uncoated base stock often provides little-to-no effective barrier against liquid water, oil/grease, or moisture transmission. Despite the lack of natural barrier performance, base sheet properties can significantly influence the efficiency of applied waterbased barrier coatings. In this study, various base stock properties, such as caliper, porosity, roughness, and ash content, are reported to influence the barrier performance of styrene-acrylic and a copolymer of styrene-butadiene/styrene-acrylate based barrier coatings. These findings will help paper and board producers design better, more cost-effective, purposebuilt substrates for barrier applications in the packaging industry.
Journal articles
A laboratory-scale automated vacuum-assisted device for coating of cellulose nanofibrils onto paper, TAPPI Journal November 2025
ABSTRACT: An automated vacuum-assisted coating system was developed to deposit cellulose nanofibril (CNF) layers onto paper substrates, simulating potential industrial geometries while allowing precise control of web speed (10•20 m/min), vacuum time (up to 30 s), and applicator gap (0.5•0.9 mm). Vacuum assistance makes it possible to obtain coat weights over 5 g/m2 in a single pass and increases solids after coating from less than 10% to over 28%• 30%, reducing drying demand by more than 60%. Coat weights were tuned from 6 to over 11 g/m² by varying suspension solids (0.4•0.6 wt%), line speed, and filtration length (20•40 mm), with strong agreement between experimental data and model predictions. Barrier testing showed Kit test values for double folded samples of 9•12 and Gurley air resistances above 4 × 104 s once coat weights exceeded 7 g/m². Comparable performance was achieved with lower fines content CNF (60%) by increasing coat weight, providing technical flexibility and cost advantages for industrial scale-up.
Journal articles
Designing paper and board barrier constructions for food contact applications, TAPPI Journal November 2025
ABSTRACT: This study examines the effect of multiple factors on barrier performance for purpose-built paper and paperboard constructions produced on an industrial pilot coater machine. Impacts from precoat latex chemistry, application method (flooded nip with bevel blade, jet with bevel blade, and pre-metered film coater, laboratory rod drawdown) and precoating calendering were studied in relation to resulting porosity, roughness, and barrier (liquid water, moisture, and oil). Results reveal a complex interaction between controllable and uncontrollable factors, offering insight for designing advanced barrier coatings on cellulosic substrates.
Journal articles
Pre-damping effects on water absorption and drying dynamics in flexographic printing, TAPPI Journal November 2025
ABSTRACT: Optimizing flexographic printability can involve the ink and the substrate, as well as the printing process. It has been widely reported in the literature that controlling topography of the substrate and its porosity are vital for good flexographic printability, especially when using water-based inks. This study focuses on how pre-damping a surface impacts liquid absorption and improves wet trapping (ink on ink with no intermediate drying) in flexographic printing. A Prüfbau universal print tester was adapted to analyze flexographic wet-on-wet ink printing and trapping using yellow and magenta inks for contrast. Slow drying of the first ink layer (yellow) leads to mottle when the second layer (magenta) is applied. The study explores the “wet sponge” hypothesis: a pre-damped surface should absorb liquid faster. The Lucas- Washburn equation describes long-term absorption, but it does not capture short-term uptake, which instead follows a linear dependence on time.
Journal articles
Editorial: TAPPI Journal eBook version offers easy content, TAPPI Journal September 2025
Many readers of TAPPI Journal are familiar with accessing the PDF version of our published research papers, but not all are familiar with the availability and functionality of our eBook version. As opposed to the traditional PDF format, which is a static digital replica of the paper, the eBook version offers a range of additional benefits that make the content more dynamic, accessible, and user-friendly. In addition, you can more easily review all papers in a particular issue much as you could in a print version, as opposed to opening multiple PDFs. Below are some highlights on accessing and making the most of the eBook version.
Journal articles
Effects of biopolymer coatings on paper permeability and capillarity for paper-based rapid diagnostic test devices, TAPPI Journal September 2025
ABSTRACT: Rapid diagnostic test (RDT) devices are widely used for diagnostics due to their affordability, portability, and user-friendliness. However, conventional assays typically rely on nitrocellulose membranes and plastic casings. These materials raise environmental concerns due to their non-renewable nature, energy-intensive production methods, and poor biodegradability. This study explores the development of fully bio-based RDT substrates using a sustainable alternative: softwoodderived microfibrillated cellulose (MFC), cellulose nanocrystals (CNC), and chitosan as surface modifiers to improve paper properties and enhance RDT sustainability. Cotton filter paper substrates were coated with different biopolymer formulations using a manual blade coater: bleached MFC (BMFC), lignin-containing MFC (LMFC), BMFC combined with CNC, LMFC combined with CNC, and chitosan. Evaluation of the most relevant physical properties concerning RDT performance was conducted, including wetting, water retention value, air permeability, capillary flow rate, and surface morphology. Results showed that biopolymer- based coatings can effectively modify surface properties by reducing pore size and tuning hydrophilicity, while maintaining the renewable and bio-based characteristics of the substrate. The LMFC-coated paper exhibited the best overall performance among all formulations, reducing flow time by 50% (3.00 mm/s vs. 1.5 mm/s) compared to the uncoated paper, yet preserving high water retention. The BMFC+CNC coating also significantly improved flow rate, showing a 36.7% reduction (2.37 mm/s vs. 1.5 mm/s), and enhanced porosity uniformity. In contrast, the flow rate of chitosan-coated paper decreased by over 5,000% (0.027 mm/s), reflecting its strong barrier properties and hydrophobic surface (highest contact angle: 91.4°). These findings suggest that MFC-based coatings are promising ecofriendly alternatives to nitrocellulose, offering optimized capillary transport and structural adaptability. This paves the way for the development of sustainable, high-performance, rapid diagnostic tests.
Journal articles
A targeted approach to produce energy-efficient packaging materials from high-yield pulp, TAPPI Journal August 2025
ABSTRACT: Unlike fossil-based plastics, wood-based packaging materials can be produced in an ecofriendly manner using wood chip residuals from sawmills and pulpwood. To produce high-yield pulp like chemithermomechanical pulps (CTMPs) for paperboard and liquid packaging, it is crucial to reduce the electric energy consumption during fiber separation. The ultimate objective is to revolutionize paperboard production by achieving a middle-layer CTMP process that consumes less than 200 kilowatt-hours per metric ton (kWh/t), significantly improving from the current 500•600 kWh/t energy demand. Optimizing the CTMP impregnation process of sodium sulfite (Na2SO3) in wood chips is crucial for achieving uniform softening, ideally at the fiber level. The properties of the fibers are significantly affected by the content of lignin sulfonates within the walls of the fiber and the middle lamellae. In this study, we employed in-house developed X-ray fluorescence (XRF) techniques, validated by beamline measurements, to map the distribution of sulfonated lignin within fibers. It also seemed possible to enhance the surface area of lignin-rich pulp fibers while losing minimal bulk by refining them with well-optimized low consistency (LC) refining. We aimed to achieve a highly efficient separation of coniferous wood fibers by co-optimizing the sulfonation and the temperature in the preheater and chip refiner. Additionally, we explored how lignin’s softening behavior and potential crosslinking influence subsequent unit operations, including pressing, peroxide bleaching, and drying, following the defibration process. In defibration during chip refining, the maximum softening of wood fibers is preferred to maximize fiber preservation and minimize energy consumption. However, optimizing the stiffness of finished pulp fibers is preferable to reduce bulk loss during paperboard production. It can strive to optimize processes to develop stronger, lighter, and more sustainable composite packaging materials. Reducing environmental impact and electric energy can help create a more sustainable future.
Journal articles
Formability and load-bearing capacity of multilayered paperboard in three-dimensional forming, TAPPI Journal August 2025
ABSTRACT: The forming of paper-based products presents significant challenges, including maintaining geometric integrity, managing springback, and overcoming instability limits. These arise from the material properties of paper, with its high anisotropy, inhomogeneity, and limited strain. Multilayered paperboard, formed without adhesives, offers a promising solution. By customizing layer composition and orientation, this approach leverages mutual fiber support to enhance forming properties. Experimental and numerical analyses reveal that adhesive-free bonding during deep drawing enhances the material’s formability and load-bearing capacity and reduces anisotropic springback. These innovations enable superior product protection compared to conventional industrial single-layered paperboard of similar thickness. This study demonstrates the advantages of tailored layer configurations for improved geometric precision and stability, providing a pathway for sustainable, high-performance packaging solutions.
Journal articles
In-situ process monitoring in deep-drawing of paper using partially transparent tools, TAPPI Journal August 2025
ABSTRACT: The production of three-dimensionally formed packaging from paper by deep drawing usually leads to the occurrence of wrinkles, which result from the high tangential compressive stresses in the flange area and the limited flowability of the material. Wrinkles, although mostly tolerated in industry, end in both a reduced visual appearance and a reduction in usability for packaging, as with, for example, when gas-tightness is required. Previous research efforts have been limited to determining the wrinkle distribution after completion of forming and removal of the formed part. Consequently, the possibility of understanding the sequence of formation of individual wrinkles in the inhomogeneous material is lost. To remedy this situation, a method for local in-situ process monitoring is presented. Using a transparent die and an industrial camera, the flange area can be observed during the forming process. An image processing algorithm is applied to analyze the local development of the deep drawing process from the continuously recorded image data. The method described can be used to analyze the draw-in behavior and wrinkle formation locally and continuously over the drawing depth. The blank holder force influences the draw-in and the wrinkle pattern both locally and throughout the drawing process. A more precise understanding of the wrinkle formation will allow for more efficient process control in the future.
Journal articles
On the design of corrugated boards: A new FEM modeling and experimental validation, TAPPI Journal August 2025
ABSTRACT: This study presents a simplified finite element modeling (FEM) approach suitable for large structures made of corrugated boards, such as customized packages, based on a homogenization method, which is combined with correction factors for internal mechanisms. The homogenization process reduces computational time by transforming flute geometries into equivalent elastic models. In large deformations and in the presence of contact for a given geometry, the effective elastic modulus in the thickness direction, as well as the effective thickness of the structure, are corrected by two statistical Weibull distributions representing the contact and buckling mechanisms in a corrugated board. The Weibull parameters are obtained via experimental analysis, and such a process is then validated. The results demonstrate that the statistical parameters (â1 = 0.14, â2 = 1.31) can be used for the simplistic representation of corrugated boards, being computationally efficient. This research contributes to the optimization of corrugated packaging design, specifically by simplifying FEM models for faster, yet equally accurate, simulations.