Search

Top 10 Practical Steps to Safe Terminations, Paper360º November/December 2022

Kotkamills’ PM1 Rebuild Will Reinforce its Position in Laminated Papers, Paper360º September/October 2022

Fixing Just One Link Doesn’t Strengthen a Chain, Paper360º September/October 2022

RISI’s 2017 Latin American CEO of the Year: An interview wi

RISI’s 2017 Latin American CEO of the Year: An interview with Walter Schalka, Suzano, Paper360º September/October 2017

Ready to Compete for Another Century, Paper360º September/Oc

Ready to Compete for Another Century, Paper360º September/October 2017

Graphic Packaging International: Safety Never Stops, Paper3

Graphic Packaging International: Safety Never Stops, Paper360º January/February 2022

It Turned into Nothing, Paper360º March/April 2022

It Turned into Nothing, Paper360º March/April 2022

Understanding Tree Growth, Harvests, and Carbon Sequestration, Paper360º March/April 2022

Understanding Tree Growth, Harvests, and Carbon Sequestration, Paper360º March/April 2022

Coping Mechanisms for the Carbon Clampdown, Paper360º May/June 2022

Impact of different calendering strategies on barrier coating pickup, TAPPI Journal November 2023

ABSTRACT: Paper was pre-calendered in a pilot scale configuration with a traditional soft nip calender and a metal belt calender. All calendering strategies reduced surface roughness and permeability of the samples, but different strategies affected the surface roughness and permeability differently. The metal belt calender seemed to have a larger effect on the large-scale variations compared to the soft nip calender. Six test points from the pilot calendered papers were chosen for laboratory coating studies. Uncalendered paper was included as reference samples. The calendered samples and the reference were pre-coated with a regular pigmented coating consisting of a ground calcium carbonate (GCC) pigment and a styrene acrylate (SA) latex. Both uncoated and pre-coated substrates were barrier coated with a polyvinyl alcohol (PVOH) in one and two layers. The coating pickup was determined gravimetrically, and the barrier properties were evaluated with TAPPI Standard Test Method T 454 grease resistance test. All samples needed two PVOH coating layers to form a grease barrier. The uncalendered sheets showed the best results with one coating layer, but this was at the expense of a higher coating pickup compared to the calendered sheets. The barrier coating pickup could be reduced by a combination of high temperature metal belt calendering and pre-coating. The high temperature and long residence time in the nip enabled plasticization of the fibers. This led to an irreversible deformation, even after water application. This meant that the smoothness obtained during calendering would be less affected by water-induced roughening during the coating operation.