Influence of refining and stock composition on the mechanical properties of a multi-ply board
2024 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE credits
Student thesisAlternative title
Effekter av raffinering och massasammansättning på de mekaniska egenskaperna hos en flerskiktskartong (Swedish)
Abstract [sv]
Handark med olika mäldkompositioner har tillverkats för att undersöka inverkan på dragegenskaper vid malning av bararmassa och utskott i mittskikten. En metod att producera handark med olika skiktstrukturer utvecklades. Inverkan på dragegenskaper av kartongstrukturen undersöktes genom att producera handark med olika strukturer med den utvecklade metodologin. Ett starkare och mer töjbart ark medfördes vid malning av barrved i mittskiktet. En liknande trend observerades när utskottet maldes. Den starkaste kartongen som producerades bestod enbart av utskott som var malt till 80 kWh/t i mittskikten. Svagaste kartongen var den med en blandning av omald barrved och omalt utskott i mittskikten. Vid jämförelse av handark bestående av ett skikt och handark med flerskiktsstruktur med samma mäld i samtliga skikt var dragindexen densamma, brottöjningen ökade och dragstyhetsindexen avtog.
Abstract [en]
Handsheets with different stock mixtures were produced to investigate how refining the softwood and broke in the center ply affects the tensile properties of a multiply board. A method to produce handsheets with different board structures was developed. The influence of board structure was also studied by combining several handsheets to different board structures. Refining softwood in the center ply lead to a stronger and more stretchable sheet. Similarly, refined broke showed a notably large increase in tensile index and strain at break. The strongest multiply board was obtained with broke refined to 80 kWh/t in the center plies. The weakest board had unrefined softwood and unrefined broke in the center ply. When comparing single-ply with multiply board structures made of the same stock in all plies, no increase in tensile index, a gain in strain at break, and a decrease in tensile stiffness index was observed.
Place, publisher, year, edition, pages
2024.
Series
TRITA-CBH-GRU ; 2024:362
Keywords [en]
Paperboard, refining, chemical pulp, stock composition, tensile properties
Keywords [sv]
Flerskiktskartong, malning, kemisk massa, massasammansättning, mekaniska egenskaper
National Category
Paper, Pulp and Fiber Technology
Identifiers
URN: urn:nbn:se:kth:diva-354922OAI: oai:DiVA.org:kth-354922DiVA, id: diva2:1906295
External cooperation
Holmen Paper Iggesund
Subject / course
Fiber Technology
Educational program
Degree of Master - Macromolecular Materials
Examiners
2024-10-172024-10-17