Influence of hardwood, softwood
and fractionated pulp in a stratified
three-layered fine paper: Lövved, barrved och fraktionerad massa och
dess inverkan på ett treskiktat finpapper
2006 (English)Independent thesis Advanced level (degree of Master (Two Years))
Student thesis
Abstract [en]
Four different trials of stratified three-layered fine paper, of sulphate pulp, were performed to investigate if stratified fine fraction or fibres from birch can improve the properties of a paper compared to a reference sheet. All trials had five different scenarios and each scenario was calendered with different linear load. All sheets had a grammage of 80 g/m2.
In the first trial, the paper contained birch, pine and filler of calciumcarbonate (marble), and was manufactured with the pilot paper machine XPM and the stratified headbox Formator at RCF (Stora Enso Research Center in Falun). The furnish consisted of 75% birch and 25% pine.
The second trial contained coated sheets with paper from trial one as the base paper. The coating slip contained calciumcarbonate and clay and the amount was approximately 10-12 g/m2.
The third trial, also with birch and pine but without filler, was performed at STFI (Skogsindustrins Tekniska Forskningsinstitut in Stockholm) with the laboratory scaled paper machine StratEx and the stratified headbox AQ-vanes. The furnish consisted of 75% birch and 25% pine, except for one scenario which contained of 75% pine and 25% birch.
The last trial contained fractionated pulp of birch and pine and was performed at STFI. 50% was fine fraction and 50% was coarse fraction.
This test does not show any clear benefits of making stratified sheets of birch and pine when it comes to properties such as bending stiffness, tensile index and surface smoothness. The retention can be improved with birch in the surface plies. It is possible that the formation can be improved with birch in the surface plies and pine in the middle ply. It is also possible that fine fraction in the surface plies and coarse fraction in the middle ply can improve both surface smoothness and bending stiffness.
The results in this test are shown with confidence intervals which points out the difficulties of analysing sheets manufactured with a pilot paper machine or a laboratory scaled paper machine.
Place, publisher, year, edition, pages
Borlänge, 2006. , p. 171
Keywords [en]
Multi-ply fine paper, three-layer fine paper, stratified forming, simultaneous forming, XPM, Formator, StratEx, AQ-vane, stratified headbox, early wood, late wood, fractionation, fine fraction, coarse fraction, hydrocyclone
Identifiers
URN: urn:nbn:se:du-2389OAI: oai:dalea.du.se:2389DiVA, id: diva2:518121
Uppsok
Technology
Supervisors
2006-11-052006-11-052012-04-24Bibliographically approved