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Spoilage Problems in Papermaking Systems, 2003 Spring Technical Conference Proceedings
Spoilage Problems in Papermaking Systems, 2003 Spring Technical Conference Proceedings
Delignification of High Kappa Number Kraft and Soda-Anthraquinone Pulps with Polyoxometalate, 2000 Pulping / Process & Product Quality Conference Proceedings
Delignification of High Kappa Number Kraft and Soda-Anthraquinone Pulps with Polyoxometalate, 2000 Pulping / Process & Product Quality Conference Proceedings
MOISTURE PICKUP IN CALCIUM CARBONATE COATING STRUCTURES: role of surface and pore structure geometry, 2008 Advanced Coating Fundamentals Symposium
MOISTURE PICKUP IN CALCIUM CARBONATE COATING STRUCTURES: role of surface and pore structure geometry, 2008 Advanced Coating Fundamentals Symposium
Advances in Design of Elastic Guiding Vanes Used in Traditional and Stratified Headboxes, 2008 PAPERCON Conference
Advances in Design of Elastic Guiding Vanes Used in Traditional and Stratified Headboxes, 2008 PAPERCON Conference
Advanced Tie Line Control for Real Time Pricing (RTP) and Waste Fuel Cogeneration, 2008 Engineering, Pulping and Environmental Conference
Advanced Tie Line Control for Real Time Pricing (RTP) and Waste Fuel Cogeneration, 2008 Engineering, Pulping and Environmental Conference
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Optimizing Pedestrian Safety with Six Sigma and Cutting-Edge Anti-Collision Systems
Optimizing Pedestrian Safety with Six Sigma and Cutting-Edge Anti-Collision Systems Register Now Overview Speaker Webinar November 4th, 2024 | 10AM (ET) John Feola Enhancing workplace safety is a
TAPPI News
If you Mess it Up, Un-Mess It!
If you Mess it Up, Un-Mess It! "If you mess it up, un-mess it."...Fred von Zueben, retired, CEO, The Newark Group I was with The Newark Group 10 years prior to coming on board with TAPPI. One of the
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
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
Colloidal silica and its effects during formation of paper sheets in the presence of nanofibrillated cellulose, cationic starch, and cationic acrylamide copolymer, TAPPI Journal May 2025
ABSTRACT: This work considered effects of colloidal silica addition during laboratory preparation of paper sheets containing nanofibrillated cellulose (NFC) that had been pretreated with cationic starch. The emphasis was on process performance issues, including dewatering rates, fine particle retention, and the extent of fiber flocculation. In addition, micrographs were obtained to show what was happening to the NFC upon treatments with cationic starch and subsequent application of hydrodynamic shear. Contrasting results were obtained, depending on the charge density of the cationic starch. Pretreatment of the NFC with a high charge density cationic starch (degree of substitution 0.2) resulted in strong interactions with the colloidal silica, enhancing the dewatering rate and contributing to fine-particle retention. The medium charge cationic starch pretreatment led to effects suggesting a bridging mechanism of action, and subsequent colloidal silica had no significant effect on dewatering. Treatment of that system with a high level of colloidal silica (0.2%) resulted in lower retention. In general, the final colloidal silica treatments tended to decrease the level of flocculation in the suspensions, giving more uniform handsheets. Mechanisms, some of them related to the clustering and dispersion of cationic starch-treated NFC, were proposed to account for the observed effects.