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A study of the impact on pulp quality of the processing steps used in the conversion of inkjet? printed commercial papers to deinked pulp by two deinking methods, 19PaperCon

A study of the impact on pulp quality of the processing steps used in the conversion of inkjet? printed commercial papers to deinked pulp by two deinking methods, 19PaperCon

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.

Predicting strength characteristics of paper in real time using process parameters, TAPPI Journal March 2022

ABSTRACT: Online paper strength testing methods are currently unavailable, and papermakers have to wait for manufacture of a complete reel to assess quality. The current methodology is to test a very small sample of data (less than 0.005%) of the reel to confirm that the paper meets the specifications. This paper attempts to predict paper properties on a running paper machine so that papermakers can see the test values predicted in real time while changing various process parameters. This study was conducted at a recycled containerboard mill in Chicago using the multivariate analysis method. The program provided by Braincube was used to identify all parameters that affect strength characteristics. Nearly 1600 parameters were analyzed using a regression model to identify the major parameters that can help to predict sheet strength characteristics. The coefficients from the regression model were used with real-time data to predict sheet strength characteristics. Comparing the prediction with test results showed good correlation (95% in some cases). The process parameters identified related well to the papermaking process, thereby validating the model. If this method is used, it may be possible to predict various elastic moduli (E11, E12, E22, etc.) in the future as the next step, rather than the traditional single number “strength” tests used in the containerboard industry, such as ring crush test (RCT), corrugating medium test (CMT), and short-span compression strength test.

Optimisation of optical coverage of board surfaces with assessment of light scattering and absorption using mineral as a coating component, TAPPICon25

Pigment loading level effects on water barrier properties in barrier coating formulations, TAPPICon25

A Systems Thinking Approach: Institutional Memory Loss in Pulp and Paper Industry, TAPPICon25

Raw Material And Energy Savings On Tissue Machines With Low Capital Investment, TAPPICon25

Experimental investigations into fold cracking of double coated barrier dispersion coatings, TAPPICon24

The influence of precoating layers on the performance of water-based barrier coatings, TAPPI Journal January 2025

Cellulose nanofibrils (CNF) on paper have been demonstrated to be an effective barrier against oxygen and grease and have been shown to improve the barrier performance of dispersion-based barrier coatings. The potential to produce paper grades that have good oxygen, grease, and moisture barrier properties is clear, but a better understanding of the synergies between CNF, other coating layers, and water-based barrier coatings (WBBC) is needed to optimize these systems. Different coat weights of a commercial WBBC were applied to papers that have a range of different qualities and thicknesses of CNF precoating layers. The same WBBC was also applied to pigmented coated paper, with various types of pigments and latex levels. Samples were characterized in terms of grease resistance, water vapor transmission rate (WVTR), and oxygen transmission rate (OTR) before and after folding. The results were contrasted to cases where the WBBC was applied to the paper with no precoating layer. When the WBBC is applied on a CNF layer or the pigmented coating layer, the performance of the WBBC for the water vapor barrier improves a significant amount compared to when the WBBC is applied to the base paper with no precoating layer. This improvement likely comes from these precoating layers filling in the large paper pores, which leads to the WBBC forming a continuous layer at low coat weights. Folding decreases the moisture barrier performance to some degree, but the grease resistance is not influenced by folding when a CNF precoating layer is involved. Oxygen barrier properties are moderate for the CNF layer alone and are less than 5 cm3/m2/day when WBBC is coated on the CNF layer. This result likely comes from the barrier coating’s ability to repair defects in the CNF layer to stop the easy passage of oxygen in defect regions of the sample.

Effect of xylan on the mechanical performance of softwood kraft pulp 2D papers and 3D foams, TAPPI Journal March 2025

ABSTRACT: Pulp fibers are paramount in paper products and have lately seen emerging use in fiber foams. Xylan, an integral component in pulp fibers, is known to contribute to paper strength, but its effect on the strength of pulp fiber foams remains less explored. In this study, we investigate the role of xylan in both 2D handsheets and 3D foams. For a softwood kraft pulp, we enzymatically removed 1% from pulp fibers and added 3% xylan to them by adsorption, corresponding to approximately a decrease of a tenth and an increase of a third of the total xylan content. The mechanical properties of 2D fiber networks, i.e., handsheets, made using the xylan-enriched pulp improved, particularly regarding tensile strength and Young’s modulus; however, the decrease in mechanical properties of handsheets made from enzymatically- treated xylan-depleted pulp was more pronounced. In 3D networks • pulp fiber foams, much less fiber-fiber contacts formed, and thus the mechanical properties were not as much influenced by removal of xylan. Furthermore, the presence of the required surfactant on the fibers, acting as debonding agent, overshadows any positive effect xylan might have on fiber-fiber bonding. We propose that the improved mechanical properties for the sheets result from a combination of an increased number of fiber-fiber bonds and higher sheet density, while the deterioration in mechanical properties of handsheets comprising enzymatically-treated fibers is caused by the opposite effect.