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Boosting the elongation potential of paper by mechanical refining and additives, 18PaperCon

Boosting the elongation potential of paper by mechanical refining and additives, 18PaperCon

Experimental investigations into fold cracking of double coated barrier dispersion coatings, TAPPI Journal November 2024

ABSTRACT: The trend for replacing single-use plastics with fiber-based barrier coated board packaging has prompted a significant amount of research. There are many proposed ways of providing suitable packaging for applications like food service. Among these are dispersion coated barriers on board, as well as laminated boards that can be produced using conventional polyethylene (PE) or new biodegradable plastics. Minerals have also been shown to be suitable additives to these coatings for improving barrier performance through surface chemistry and by increasing the tortuosity of the pathway through the barrier layer. They also improve the cost effectiveness of the layer by lowering the material cost and raising the solids content, and by improving hold out of the functional layers, leading to a reduction in the amount of barrier coating needed to meet a given performance requirement. Minerals can also aid in the barrier handling in terms of rheology and reduced “stickiness,” as well as blocking of the films. When incorporated as fillers into extruded films, improved adhesion of the film to the board has been reported. One of the remaining challenges is the potential for cracking at the fold during converting and the loss of barrier performance that this can lead to. In this work, we systematically looked at the impact of mineral type and level in a dispersion coating. We assessed the differences in performance resulting from different coating application methods for the precoat layer by looking at the cracking tendency and loss of barrier functionality after folding for both the precoat alone and the final double coated sheets. Barrier results include moisture vapor transmission rate (MVTR), viscous vegetable oil, and the fluid blue stain in industrial methylated spirits (IMS) and Cobb water absorption, both before and after folding.

Paper strength factors in systems with nanofibrillated cellulose, cationic starch, colloidal silica, cationic acrylamide copolymer, and hydrodynamic shear, TAPPI Journal May 2025

ABSTRACT: Laboratory paper sheets were formed by first pretreating nanofibrillated cellulose (NFC) with cationic starch at the 5% level by mass. The treated NFC was then added to stock prepared from 100% recycled copy paper. The combined furnish was next optionally treated with a cationic retention aid (cPAM, 0.1%) and then colloidal silica (0.1% or 0.2%). Vacuum dewatering, fine-particle retention, and several paper properties were studied as a function of the colloidal silica level (zero, 1%, and 2%) and at different levels of shear stress applied just before forming the sheets. Dewatering and strength results were generally more favorable when using a medium charge cationic starch (~ 0.03 degree of substitution, DS) to pretreat the NFC rather than a high charge density cationic starch (~ 0.2 DS). In each case, the dewatering was further enhanced by subsequent treatments by cPAM (0.1% on whole furnish solids) and then even more with the final addition of colloidal silica (0.1% and 0.2% levels compared). However, the colloidal silica additions progressively hurt the tensile strength of the paper, especially in the case of the high charge cationic starch and at the higher level of colloidal silica. Though the dewatering performance was favorable, in such cases, the paper strength was not improved compared to paper made without any NFC. The fact that the systems involving cPAM treatment, and especially those involving both cPAM and colloidal silica, tended to reduce the resulting paper’s tensile strength supports a mechanism in which the additives result in the clustering of the NFC, possibly in multiparticle bunches. Evidence suggests that such bunches of clustered NFC particles, which are difficult to redisperse even at levels of hydrodynamic shear present in high-speed paper machine systems, are resistant to full integration into the sheet structure as the paper is being formed.

Boiler retrofit improves efficiency and increases biomass firing rates, TAPPI Journal March 2021

ABSTRACT: Domtar’s fluff pulp mill in Plymouth, NC, USA, operates two biomass/hog fuel fired boilers (HFBs). For energy consolidation and reliability improvement, Domtar wanted to decommission the No. 1 HFB and refurbish/retrofit the No. 2 HFB. The No. 2 HFB was designed to burn pulverized coal and/or biomass on a traveling grate. The steaming capacity was 500,000 lb/h from coal and 400,000 lb/h from biomass. However, it had never sustained this design biomass steaming rate. As the sole power boiler, the No. 2 HFB would need to sustain 400,000 lb/h of biomass steam during peak loads. An extensive evaluation by a combustion and boiler technologies supplier was undertaken. The evaluation involved field testing, analysis, and computational fluid dynamics (CFD) modeling, and it identified several bottle-necks and deficiencies to achieving the No. 2 HFB’s biomass steam goal. These bottlenecks included an inadequate combustion system; insufficient heat capture; excessive combustion air temperature; inadequate sweetwater con-denser (SWC) capacity; and limited induced draft fan capacity.To address the identified deficiencies, various upgrades were engineered and implemented. These upgrades included modern pneumatic fuel distributors; a modern sidewall, interlaced overfire air (OFA) system; a new, larger economizer; modified feedwater piping to increase SWC capacity; replacement of the scrubber with a dry electrostatic precipitator; and upgraded boiler controls.With the deployment of these upgrades, the No. 2 HFB achieved the targeted biomass steaming rate of 400,000 lb/h, along with lowered stack gas and combustion air temperatures. All mandated emissions limit tests at 500,000 lb/h of steam with 400,000 lb/h of biomass steam were passed, and Domtar reports a 10% reduction in fuel firing rates, which represents significant fuel savings. In addition, the mill was able to decommission the No. 1 HFB, which has substantially lowered operating and maintenance costs.

STAR - November 2025 - Standards Coming Up For Review

TAPPI announces the 2025 Standards review schedule for pulp, paper, and packaging testing methods, providing experienced professionals opportunity to influence industry standards development. Senior members can join Standard-Specific Interest Groups to review drafts, submit expert comments, and cast official votes on critical testing procedures spanning fiber glass mats, corrugated board construction, moisture analysis, and coating technologies. The review process begins January 2026 with key standards including defect estimation, bending resistance testing, and pollutant aging methods. Legacy professionals seeking to maintain technical influence and contribute specialized knowledge can request SSIG voting membership through standards@tappi.org before target ballot dates to ensure continued impact on industry best practices.

All Eyes on the Frontline Worker

How Apple Vision Pro is revolutionizing manufacturing and edges the industrial metaverse closer.

Resources on Demand

Welcome! This page gathers free resources for readers that are available from vendors, manufacturers, associations, and others within the pulp, paper, tissue, and packaging industries—simply use the QR codes to learn more.

Kraft Recovery Operations Course

One of TAPPI's highest rated, longest running events! You'll learn ways to improve pulp production efficiency, minimize operating costs and reduce environmental impact. This course is designed for pulp mill operations personnel.

Flow Control Presents Revolutionary Product and Process Innovation

Latex Modification of Urea Formaldehyde Resins: A Review and New Approaches, 1997 Nonwovens Conference Proceedings

Latex Modification of Urea Formaldehyde Resins: A Review and New Approaches, 1997 Nonwovens Conference Proceedings