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Höglund, Hans
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Publications (10 of 78) Show all publications
Engberg, B. A., Vuorio, P., Granfeldt, T., Ahlzén, P.-J., Lundfors, M., Pettersson, G. & Höglund, H. (2022). Abrasive refining of spruce TMP and CTMP fibers. In: Proceedings of the International Mechanical Pulping Conference: . Paper presented at IMPC 2022, Vancouver, BC, Canada, June 5-8, 2022 (pp. 57-62).
Open this publication in new window or tab >>Abrasive refining of spruce TMP and CTMP fibers
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2022 (English)In: Proceedings of the International Mechanical Pulping Conference, 2022, p. 57-62Conference paper, Published paper (Other academic)
Abstract [en]

Most of the earlier proposed ways to reduce energy con-sumption in high consistency refining requires operating at a small disc gap. However, a small gap is often associated with a severe fiber length reduction and often lead to unsta-ble refining and a small operational window. To address these issues, the idea of utilizing abrasive segments surfaces is here revisited. Abrasive refiner segments, consisting of abrasive surfaces in combinations with traditional bars and grooves or flat abrasive surfaces without any bars or grooves, were evaluated in both pilot and mill scale. From the trials it could be concluded, that particularly stable refin-ing was achieved with less power variations compared to when using standard segments, even when refining at very small disc gaps. The lw-mean fiber length of the pulps was not reduced or only slightly reduced, even when refining at very small disc gaps. Tensile index could be increased more efficiently or equally efficient as when using standard seg-ments. Improved energy efficiency could be achieved when combining the abrasive surface with high intensity treat-ment.

Keywords
Pulp refining, abrasive segments, disc gap, power variations, long fiber
National Category
Wood Science
Identifiers
urn:nbn:se:miun:diva-47683 (URN)
Conference
IMPC 2022, Vancouver, BC, Canada, June 5-8, 2022
Available from: 2023-02-27 Created: 2023-02-27 Last updated: 2023-02-27Bibliographically approved
Pettersson, G., Norgren, S., Engstrand, P., Rundlöf, M. & Höglund, H. (2021). Aspects on bond strength in sheet structures from TMP and CTMP - a review. Nordic Pulp & Paper Research Journal, 36(2), 177-213
Open this publication in new window or tab >>Aspects on bond strength in sheet structures from TMP and CTMP - a review
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2021 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 36, no 2, p. 177-213Article, review/survey (Refereed) Published
Abstract [en]

High yield pulps (HYP), manufactured in mechanical and chemimechanical pulping processes, are mainly used in graphic papers and paper grades where a high bulk is preferable, like in paperboards. Moreover, packaging papers with very high demands on both dry and wet strength could be manufactured from HYP in a near future. Preferred bonds between fibre components (long fibres, shortened fibres and fines) in the various paper grades are quite different. In the review, plausible effects of mechanical interlocking, intermolecular interactions ("physical bonding"), hydrogen bonds, intermixing of polymers, additives and possible specific interactions in the formation of strong bonds in sheet structures from HYP are discussed. A required condition for high bond strength in sheets from HYP furnishes is that fibre components are forced into sufficiently close contact. This is to a great extent impeded if the fibre walls are too stiff. Consequently, the current review focuses on both how fibre fractions should preferably be developed for different end uses and how suitable bonds might be achieved in different paper grades. The ideal type of bonds is certainly different depending on the demands on the final paper quality.

Keywords
bond strength, graphic papers, mechanical pulps, packaging paper, paper strength
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-42767 (URN)10.1515/npprj-2021-0009 (DOI)000663328700001 ()2-s2.0-85106384979 (Scopus ID)
Available from: 2021-08-11 Created: 2021-08-11 Last updated: 2021-08-11
Joelsson, T., Pettersson, G., Norgren, S., Svedberg, A., Höglund, H. & Engstrand, P. (2020). High strength paper from high yield pulps by means of hot-pressing. Nordic Pulp & Paper Research Journal, 35(2), 195-204
Open this publication in new window or tab >>High strength paper from high yield pulps by means of hot-pressing
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2020 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 35, no 2, p. 195-204Article in journal (Refereed) Published
Abstract [en]

The hypothesis is that it should be possible to modify papermaking conditions in line with the softening properties of high yield pulp fibres and achieve similar strength properties to conventional chemical pulp based paper. We therefore investigated the rheological and physical properties of high yield pulp based papers during hot-pressing. Our results confirm that increased temperature combined with sufficient pressure enables permanent densification by softening of lignin, producing very high tensile strength. This treatment also significantly improved the wet tensile strength in comparison to bleached kraft pulp without using wet strength agents. The high yield pulps used here were spruce based thermomechanical pulp, chemi-thermomechanical pulp, and high temperature chemi-thermomechanical pulp, and birch-aspen based neutral sulphite semi chemical pulp, with spruce-pine based bleached kraft pulp as reference. Rapid Köhten sheets of 150g/m2 and 50 % dryness were hot-pressed in a cylinder-press at 20–200 °C, 7 MPa, and 1 m/min. The mechanical properties showed great improvements in these high yield pulp papers, with tensile index increased to 75 kNm/kg and compression strength index to 45 kNm/kg; levels close to and better than bleached kraft. Wet strength increased to 16 Nm/g compared to 5 Nm/g for bleached kraft.

Place, publisher, year, edition, pages
De Gruyter Open, 2020
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-38356 (URN)10.1515/npprj-2019-0087 (DOI)000537597900004 ()2-s2.0-85081396997 (Scopus ID)
Projects
EcoMat
Available from: 2020-02-04 Created: 2020-02-04 Last updated: 2023-10-20Bibliographically approved
Joelsson, T., Pettersson, G., Norgren, S., Svedberg, A., Höglund, H. & Engstrand, P. (2020). Improved paper wet-strength by increasing lignin content and hot-pressing temperature.
Open this publication in new window or tab >>Improved paper wet-strength by increasing lignin content and hot-pressing temperature
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2020 (English)In: Article in journal (Refereed) Submitted
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-38357 (URN)
Available from: 2020-02-04 Created: 2020-02-04 Last updated: 2023-10-20Bibliographically approved
Joelsson, T., Pettersson, G., Norgren, S., Svedberg, A., Höglund, H. & Engstrand, P. (2020). Improving paper wet strength via increased lignin content and hot-pressing temperature. TAPPI Journal, 19(10), 487-499
Open this publication in new window or tab >>Improving paper wet strength via increased lignin content and hot-pressing temperature
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2020 (English)In: TAPPI Journal, ISSN 0734-1415, Vol. 19, no 10, p. 487-499Article in journal (Refereed) Published
Abstract [en]

It is known that the strength properties of wood-based paper materials can be enhanced via hot-pressing techniques. Today, there is a desire not only for a change from fossil-based packaging materials to new sustainable bio-based materials, but also for more effective and eco-friendly solutions for improving the dry and wet strength of paper and board. Against this background, hot pressing of paper made from high yield pulp (HYP), rich in lignin, becomes highly interesting. This study investigated the influence of pressing temperature and native lignin content on the properties of paper produced by means of hot pressing. Kraft pulps of varied lignin content (kappa numbers: 25, 50, 80) were produced at pilot scale from the same batch by varying the cooking time. We then studied the effect of lignin content by evaluating the physical properties of Rapid When sheets after hot pressing in the temperature range of 20 degrees C-200 degrees C with a constant nip pressure of 7 MPa. The pilot-scale cooked pulps were compared with reference samples of mill-produced northern bleached softwood kraft (NBSK) pulp and mill-produced chemithermomechanical pulp (CTMP). Generally, the results demonstrated that lignin content had a significant effect on both dry and wet tensile index. All of the pilot cooked pulps with increased lignin content had a higher tensile index than the reference NBSK pulp. To obtain high tensile index, both dry and wet, the pressing temperature should be set high, preferably at least 200 degrees C; that is, well above the glass transition temperature (Tg) for lignin. Moreover, the lignin content should preferably also be high. All kraft pulps investigated in this study showed a linear relationship between wet strength and lignin content.

National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-40654 (URN)10.32964/TJ19.10.487 (DOI)000586835000002 ()2-s2.0-85096980972 (Scopus ID)
Available from: 2020-12-03 Created: 2020-12-03 Last updated: 2021-11-16Bibliographically approved
Joelsson, T., Pettersson, G., Norgren, S., Svedberg, A., Höglund, H. & Engstrand, P. (2019). Improving paper wet-strength by means hot-pressing and increased lignin content in pulp fibers. In: Paper Conference and Trade Show, PaperCon 2019: . Paper presented at Paper Conference and Trade Show, PaperCon 2019, 5 May 2019 through 8 May 2019 (pp. 704-713). TAPPI Press
Open this publication in new window or tab >>Improving paper wet-strength by means hot-pressing and increased lignin content in pulp fibers
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2019 (English)In: Paper Conference and Trade Show, PaperCon 2019, TAPPI Press, 2019, p. 704-713Conference paper, Published paper (Refereed)
Abstract [en]

The research presented here show ways to improve wet strength by means of hot-pressing without strength additives when using lignin containing pulps as unbleached softwood chemical pulps (NSK) and lignin rich softwood chemithermomechanical pulps (CTMP). NSK (Northern Softwood kraft) laboratory scale produced pulps of 3 different levels of natural lignin (or kappa number) and two commercial pulps, NBSK (Northern Bleached Softwood kraft) and CTMP, were compared evaluating dry- and wet-strength properties. Staining methods and light microscope were used to study cross sections of paper sheets. The CTMP fibers collapse to an increasing degree with pressing temperature whereas NBSK/NSK do not change. The microscopy methods show the distribution of lignin within the paper structure. Sheets made from NSK show a significant increase in wet strength from 4kNm/kg to 23kNm/kg, when increasing temperature from 20°C to 200°C. CTMP show corresponding increase from 2kNm/kg to 16kNm/kg. No increase in dry strength or in density can be observed in case of NBSK/NSK, while the CTMP show an increase of 53% and 100% respectively. The SCT values show an increase up to 35% for lignin-rich NSK based paper sheets when hot-pressing. 

Place, publisher, year, edition, pages
TAPPI Press, 2019
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-40695 (URN)2-s2.0-85096714336 (Scopus ID)9781510893948 (ISBN)
Conference
Paper Conference and Trade Show, PaperCon 2019, 5 May 2019 through 8 May 2019
Available from: 2020-12-08 Created: 2020-12-08 Last updated: 2023-10-20Bibliographically approved
Höglund, H., Pettersson, G., Norgren, S. & Engstrand, P. (2018). A paper or paperboard product comprising at least one ply containing high yield pulp and its production method. se 540115 C2.
Open this publication in new window or tab >>A paper or paperboard product comprising at least one ply containing high yield pulp and its production method
2018 (English)Patent (Other (popular science, discussion, etc.))
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-33506 (URN)
Patent
SE 540115 C2 (2018-04-03)
Available from: 2018-04-17 Created: 2018-04-17 Last updated: 2020-08-19Bibliographically approved
Samuelsson, T., Pettersson, G., Norgren, S., Svedberg, A., Höglund, H. & Engstrand, P. (2018). Development of strong and water resistant packaging materials from high yield pulps – fundamental aspects. In: IMPC 2018: . Paper presented at International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway. Trondheim, Norway
Open this publication in new window or tab >>Development of strong and water resistant packaging materials from high yield pulps – fundamental aspects
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2018 (English)In: IMPC 2018, Trondheim, Norway, 2018Conference paper, Published paper (Refereed)
Abstract [en]

This work is focused on fundamental aspects of the densification of paper sheets during hot-pressing under conditions where the lignin in the fibre walls is softened. In this study light microscope and scanning electron microscope (SEM) techniques were used to reveal the mechanisms in the fibre network structure within the paper sheets that arises due to densification and the impact of lignin. UV and staining methods and spectrometric observations of the ultrastructure of cross section of paper sheets and fibre surfaces will highlight the changes that occur in the fibre structures. This study improves the understanding of how fibres collapse and how internal fibre-fibre bonds in lignin-rich mechanical pulp affect the physical properties of the final paper sheet. To demonstrate this, paper sheets from five different pulps containing different concentration of natural lignin were produced. Handsheets of 150 g/m2 were prepared in a Rapid Köthen (RK) laboratory sheet former, where the sheets were press-dried at 100 kPa and ca 90oC to a dry content of 45-50% d.c. After 24 hours in room temperature the hand sheets were hot-pressed in a temperature interval from 20 – 200oC at a constant pressure in a cylinder-press at a speed of 1 m/min. The results show that remarkable improvements on paper sheets, based lignin-rich pulps, can be achieved in terms of increased tensile index (up to 85 kNm/kg), compression strength, SCT, (up to 38 kNm/kg) and wet strength (up to 10 kNm/kg), which depends on the densification of the fibre structure at high temperature and pressure in the load nip. It is concluded that this to a major extent is related to that the lignin rich fibres are compressed at high enough temperature to both softened and develop tacky surfaces so that the fibres are locked into their positions within the highly densified sheets. The SEM evaluation shows how the surface structure get dense at pressing at 200oC for the CTMP based paper sheets. The light microscopy studies of the sheet cross sections reveal how the fibres collapse in the case of CTMP based sheets while fibres from bleached kraft pulp based sheets are quite well collapsed already at room temperature.

Place, publisher, year, edition, pages
Trondheim, Norway: , 2018
Keywords
ctmp, densification, hand sheets, hyp, lignin, mechanical pulp, nssc, strength properties, tmp, wet strength
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:miun:diva-34675 (URN)
Conference
International Mechanical Pulping Conference (IMPC) 2018, May 27-30, 2018, Trondheim, Norway
Available from: 2018-10-09 Created: 2018-10-09 Last updated: 2023-10-20Bibliographically approved
Norgren, S., Pettersson, G. & Höglund, H. (2018). Strong paper from spruce CTMP - Part II: Effect of pressing at nip press temperatures above the lignin softening temperature. Nordic Pulp & Paper Research Journal, 33(1), 142-149
Open this publication in new window or tab >>Strong paper from spruce CTMP - Part II: Effect of pressing at nip press temperatures above the lignin softening temperature
2018 (English)In: Nordic Pulp & Paper Research Journal, ISSN 0283-2631, E-ISSN 2000-0669, Vol. 33, no 1, p. 142-149Article in journal (Refereed) Published
Abstract [en]

The main objective of the current study was to demonstrate that it is possible to enhance strength properties of sheets from spruce HT-CTMP and CTMP furnishes up to the same level as is common on sheets from softwood kraft pulps by changing conditions in papermaking. To achieve that, sheets of spruce HT-CTMP and CTMP were consolidated at densities close to that of the reference bleach kraft pulp by pressing at press nip temperatures well above the tack and softening temperatures of lignin. On sheets from spruce CTMP (CSF 420 ml), where the fibers were surface treated with cationic starch, it was possible to reach tensile index at the same level as on sheets from the untreated reference kraft pulp. The compression strength (SCT) of CTMP and HT-CTMP sheets, which were achieved at the highest press nip temperature (200 °C) in the study, was equal to or higher than that of the reference kraft pulp sheets. The results show that there is a great yet unexploited potential in papermaking from spruce HT-CTMP and CTMP furnishes, which could be utilized in manufacturing of products where very high requirements upon strength is demanded. 

Keywords
adsorption, CMC, CTMP, heat, polyelectrolytes, pressure, starch, tensile index
National Category
Chemical Engineering
Identifiers
urn:nbn:se:miun:diva-34544 (URN)10.1515/npprj-2018-3009 (DOI)000450919200016 ()2-s2.0-85048028992 (Scopus ID)
Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2019-08-06Bibliographically approved
Pettersson, G., Höglund, H., Norgren, S., Engstrand, P., Peng, F., Granfeldt, T., . . . Joelsson, T. (2018). Upgrading the strength properties of sheets from hardwood high yield pulps. In: Pan Pacific Fibre Value Chain Conference 2018, Proceedings: . Paper presented at 2018 Pan Pacific Fibre Value Chain Conference and Expo, New Zealand, 4 December 2018 through 7 December 2018 (pp. 142-147). Appita Inc.
Open this publication in new window or tab >>Upgrading the strength properties of sheets from hardwood high yield pulps
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2018 (English)In: Pan Pacific Fibre Value Chain Conference 2018, Proceedings, Appita Inc. , 2018, p. 142-147Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Appita Inc., 2018
Keywords
CMC, CTMP, Polyelectrolytes, Pressure heat, Starch, Tensile index, Dyes, Fibers, Hardwoods, Manufacture, Pulp refining, Surface treatment, Cationic starches, Compression index, Compression strength, Number of contacts, Softening temperature, Strength property, Pulp
Identifiers
urn:nbn:se:miun:diva-36664 (URN)2-s2.0-85064969968 (Scopus ID)9780975746998 (ISBN)
Conference
2018 Pan Pacific Fibre Value Chain Conference and Expo, New Zealand, 4 December 2018 through 7 December 2018
Available from: 2019-07-09 Created: 2019-07-09 Last updated: 2019-07-09Bibliographically approved
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