Nano-lignocellulose from recycled fibres in coatings from aqueous and ethanolic media: Effect of residual lignin on wetting and offset printing quality

Research output: Contribution to journalArticleScientificpeer-review

Researchers

Research units

  • Gorgan University of Agricultural Sciences and Natural Resources

Abstract

Nano-lignocellulose (NLC) and lignin-free nanocellulose (nano-holocellulose, NHC) were used in paper coating to investigate their effect on coating layer quality and offset printing. The NLC was produced by microfluidisation of unbleached secondary fibres while the reference NHC was obtained from the same fibre source after lignin removal (OHE P H bleaching), following the same mechanical process. TEMPO-mediated oxidation of the fibres prior to microfluidisation was applied to increase the electrostatic charge and hydrophilicity of the nanofibrils. The coatings, displaying given surface morphology and energy, were applied on Kraft, printing-grade papers at three grammage levels. The structure of the coated and uncoated (reference) papers were accessed (SEM and AFM) and IGT printing was carried out to determine the print density, print gloss, rub-off resistance, surface energy, roughness, ink transfer, dry pick resistance, water interference and set-off. The results highlight the important effect of residual lignin or type of nanocellulose on the coating layer and the development of offset printing properties. It was observed that roughness was a key factor leading to a deterioration of the print properties, predominantly affecting the NLC coating. Considering the lower hydrophilicity of NLC, an alternative dispersion with water-alcohol mixtures is proposed. By using this dispersing medium, tailorable surface coverage, surface smoothness, ink acceptance and improved printability was achieved. We show that under these conditions and compared to NHC, NLC is equally effective as a coating layer.

Details

Original languageEnglish
Pages (from-to)200-210
Number of pages11
JournalNordic Pulp and Paper Research Journal
Volume34
Issue number2
Publication statusPublished - Jun 2019
MoE publication typeA1 Journal article-refereed

    Research areas

  • coating, nano-holocellulose (NHC), nano-lignocellulose (NLC), offset printing, surface properties, NANOCELLULOSE, PHYSICAL-PROPERTIES, CELLULOSE NANOFIBRILS, COATED PAPER, PRINTABILITY, SURFACE-ENERGY, FILMS, LIQUID ABSORPTION

ID: 33286558