{{Short description|Paper created exclusively from chemical pulp}} {{About|paper made from bleached, lignin-free pulp|other paper from non-wood sources|List of types of paper#Types of paper by cellulose source}} {{Use dmy dates|date=April 2026}} thumb|A sheet of wood-free paper
'''Wood-free paper''', '''tree-free paper''', or '''fine paper''' is paper created from bleached, chemically-separated paper pulp, as to minimize lignin contents (the "wood" in question).<ref>{{Cite journal |last1=He |first1=Zhibin |last2=Hui |first2=Lanfeng |last3=Liu |first3=Zhong |last4=Ni |first4=Yonghao |last5=Zhou |first5=Yajun |date=1 April 2010 |title=Impact of High-Yield Pulp Substitution on the Brightness Stability of Uncoated Wood-Free Paper |journal=TAPPI Journal |volume=9 |issue=3 |pages=15–20 |doi=10.32964/tj9.3.15 |issn=0734-1415 |doi-access=free }}</ref> It is not as susceptible to yellowing as paper containing mechanical pulp.<ref>{{Citation |last=Bajpai |first=Pratima |title=The Control of Microbiological Problems∗∗Some excerpts taken from Bajpai P (2012). Biotechnology for Pulp and Paper Processing with kind permission from Springer Science1Business Media. |date=2015 |journal=Pulp and Paper Industry |pages=103–195 |publisher=Elsevier |doi=10.1016/b978-0-12-803409-5.00008-2 |isbn=9780128034095 |s2cid=89782614 |doi-access=free |pmc=7158184 }}</ref><ref>{{Cite web |date=10 May 2016 |title=Print lingo explained: Woodfree paper |url=https://www.warners.co.uk/blog/woodfree-paper |access-date=10 December 2022 |website=Warners Midlands Plc |language=en |archive-date=10 December 2022 |archive-url=https://web.archive.org/web/20221210222603/https://www.warners.co.uk/blog/woodfree-paper |url-status=dead }}</ref><ref>{{Cite web |last=Papers |first=Peters |date=12 March 2020 |title=Know your paper terms: Wood-free paper |url=https://www.peterspapers.co.za/know-your-paper-terms-wood-free-paper/ |access-date=10 December 2022 |website=Peters Papers |language=en-US }}</ref> == Overview == === Lignin === {{Main|Lignin}} Lignin is a natural complex polymer containing aromatic compounds that provide much of a plant's strength. In its natural form, it gives rigidity and resilience to the plant's structure, but its presence causes paper to weaken and turn yellow as it ages and eventually disintegrate. The reason for this is that as the paper ages, lignin releases acid which degrades the paper.<ref>{{Cite web |title=The Coniferous - Leading Paper Trading Company |url=https://theconiferous.com/ |access-date=19 October 2023 |website=theconiferous.com |language=en }}</ref> Lignocellulose from the xylem of shrubs and cambium from the inner bark of trees are made up of lignin, hemicellulose and cellulose, relevant to papermaking.<ref name="Biermann" />
=== Pulp === {{main|Pulp (paper)}} Paper pulp consists of cellulosic materials that have been broken down chemically and physically and filtered and mixed in water to reform into a web: creating pulp by breaking down the materials chemically is called chemical pulping, while creating pulp by breaking them down mechanically is called mechanical pulping.<ref name="Biermann">Biermann, C. J. (1996). ''Handbook of pulping and papermaking''. Elsevier.</ref><ref name="Roberts" />
In the chemical pulping of lignocellulose - plants with lignin content - chemicals separate the wood fibers. The chemicals lower the lignin content because chemical action solubilizes and degrades components of wood fibers, especially hemicelluloses and lignin. Chemical pulping yields single unbroken fibers that produce strong quality papers because the lignin that interferes with hydrogen bonding of wood fibers has been removed. Chemical pulps are used to create wood free paper that is of high quality and lasts long, such as is used in arts and archiving.<ref name="Biermann" /> Chemical pulping processes take place at high pressures and temperatures under aqueous alkaline, neutral or acidic conditions, with the goal of totally removing the lignin and preserving the carbohydrates. Normally, about 90% of the lignin is removed.<ref name="Roberts">J.C. Roberts, The Chemistry of Paper, 1st edn., Cambridge, 1996</ref>
Mechanical pulping, in contrast, converts raw lignocellulose into pulp without separating the lignin from the cellulose.<ref name="Roberts" /> No chemicals other than water or steam are used. The yield is about 90% to 98%. High yields result from the fact that lignin is retained. Mechanical pulps are characterized by low cost, high stiffness, high bulk, and high yield. Mechanical pulp has low strength because the lignin interferes with hydrogen bonding between wood fibers. The lignin also makes the pulp turn yellow when exposed to light and air. Mechanical pulps are used in the production of non-permanent papers such as newsprint and magazine paper. Mechanical pulps made up 20% to 25% of the world production and this is increasing because of the high yield of the process and increasing competition for fiber resources. Advances in technology have also made mechanical pulp increasingly desirable.{{what|date=September 2025}}<ref name="Biermann" />
== Categories == ===Woodfree uncoated paper===
'''Woodfree uncoated paper''' ('''WFU'''), '''uncoated woodfree paper''' ('''UWF''') or '''uncoated fine papers''' is the paper industry technical term for base wood-free paper.<ref>{{Cite web |url=http://paperonweb.com/grade11.htm |title=The paper made without using mechanical pulp |access-date=26 September 2025 |archive-date=5 April 2015 |archive-url=https://web.archive.org/web/20150405035847/http://paperonweb.com/grade11.htm |url-status=dead }}</ref> Both softwood and hardwood chemical pulps are used and a minor part of mechanical pulp might be added (often of aspen or poplar). These paper grades are calendered.<ref>{{Cite book |last=Tillmann |first=Otmar |url=https://onlinelibrary.wiley.com/doi/10.1002/3527608257.ch11 |title=Paper and Board Grades and Their Properties |date=20 January 2006 |at=6.9.4.2.1 & 6.9.4.2.2}}</ref> The properties are good strength, high brightness and good archival characteristics.<ref name=WFU>{{cite book |last1=Paulapuro |first1=Hannu |title=Paper and Board grades |series=Papermaking Science and Technology |volume=18 |year=2000 |publisher=Fapet Oy |location=Finland |isbn=952-5216-18-7 |pages=35–37 |chapter=1 }}</ref> They provide less glare than woodfree coated paper (WFC) as there is no coating involved.<ref>{{Cite web |title=Quality Wood Free Coated Paper Suppliers |url=https://www.pgpaper.com/woodfree-coated-paper/ |access-date=2026-04-18 |website=PG Paper |language=en-GB}}</ref>
=== Offset paper === '''Offset paper''' is a type of woodfree uncoated paper primarily designed for offset printing. It can range from 60 gsm (grammage, or grams per square meter), to over 200 gsm. Lighter weights can compose brochures and flyers, while heavier weights are used for packaging and other durable applications.<ref>{{Cite web |title=Offset Paper: Types, Weights & How to Pick the Right One |url=https://www.mailpro.org/post/what-is-offset-paper |access-date=2026-04-18 |website=Mail Processing Associates |language=en}}</ref> SC (supercalendered) offset paper has an ISO brightness of > 67% and a surface strength is optimized for offset printing.<ref>{{Cite web |last=Tillmann |first=Otmar |date=20 January 2006 |title=Handbook of Paper and Board |url=https://onlinelibrary.wiley.com/doi/10.1002/3527608257.ch11 |at=11.2.1.1.2}}</ref>
== Composition == {{Essay-like|section|date=August 2024}} Wood-free paper is made from a variety of raw materials, including * Tissue pulp: This is the most common type of wood-free paper. It is made from wood pulp that has been treated with chemicals to remove the lignin.<ref name="Nordic Pulp p297-305">{{Cite journal |last1=Manninen |first1=Marjo |last2=Kajanto |first2=Isko |last3=Happonen |first3=Juha |last4=Paltakari |first4=Jouni |date=1 August 2011 |title=The effect of microfibrillated cellulose addition on drying shrinkage and dimensional stability of wood-free paper |url=http://dx.doi.org/10.3183/npprj-2011-26-03-p297-305 |journal=Nordic Pulp & Paper Research Journal |volume=26 |issue=3 |pages=297–305 |doi=10.3183/npprj-2011-26-03-p297-305 |s2cid=137540823 |issn=2000-0669 |url-access=subscription }}</ref><ref>{{Cite journal |last1=Kemppainen |first1=K. |last2=Siika-aho |first2=M. |last3=Pattathil |first3=S. |last4=Giovando |first4=S. |last5=Kruus |first5=K. |date=January 2014 |title=Spruce bark as an industrial source of condensed tannins and non-cellulosic sugars |url=http://dx.doi.org/10.1016/j.indcrop.2013.10.009 |journal=Industrial Crops and Products |volume=52 |pages=158–168 |doi=10.1016/j.indcrop.2013.10.009 |bibcode=2014IndCP..52..158K |issn=0926-6690 |url-access=subscription }}</ref><ref>{{Cite journal |last1=Kumar |first1=Varun |last2=Pathak |first2=Puneet |last3=Bhardwaj |first3=Nishi Kant |date=February 2020 |title=Waste paper: An underutilized but promising source for nanocellulose mining |url=http://dx.doi.org/10.1016/j.wasman.2019.10.041 |journal=Waste Management |volume=102 |pages=281–303 |doi=10.1016/j.wasman.2019.10.041 |pmid=31704510 |bibcode=2020WaMan.102..281K |s2cid=207965485 |issn=0956-053X |url-access=subscription }}</ref><ref>{{Cite journal |last=Bajpai |first=P. |date=5 April 1999 |title=Application of Enzymes in the Pulp and Paper Industry |url=http://dx.doi.org/10.1021/bp990013k |journal=Biotechnology Progress |volume=15 |issue=2 |pages=147–157 |doi=10.1021/bp990013k |pmid=10194388 |bibcode=1999BioPr..15..147B |s2cid=26080240 |issn=8756-7938 |url-access=subscription }}</ref> * Balsa pulp: This is a type of wood pulp that is made from balsa trees. It is very strong and lightweight, making it ideal for use in envelopes and other lightweight applications.<ref>{{Cite journal |last1=Wong |first1=C.H. |last2=Nicholas |first2=J. |last3=Holt |first3=G.D. |date=1 April 2003 |title=Using multivariate techniques for developing contractor classification models |url=http://dx.doi.org/10.1108/09699980310466587 |journal=Engineering, Construction and Architectural Management |volume=10 |issue=2 |pages=99–116 |doi=10.1108/09699980310466587 |issn=0969-9988 |url-access=subscription }}</ref><ref>{{Cite book |last=American Institute of Timber Construction |url=http://dx.doi.org/10.1002/9781118279687 |title=Timber Construction Manual |date=16 July 2012 |publisher=Wiley |doi=10.1002/9781118279687 |isbn=978-0-470-54509-6 }}</ref> * Coniferous pulp: This is a type of wood pulp that is made from coniferous trees, such as pine and fir. It is strong and durable, making it ideal for use in writing and printing papers.<ref name="SouthA">{{Cite journal |last=Windrich |first=E. |date=1 January 1998 |title=Book Reviews : Adebayo Adedeji (ed.), South Africa and Africa: Within or Apart'? (London: Zed Books and Cape town: SADRI Books, 1996), xiii, 258 pp. Cloth $55.00, paper $19.95 |url=http://dx.doi.org/10.1177/002190969803300306 |journal=Journal of Asian and African Studies |volume=33 |issue=3 |pages=278–279 |doi=10.1177/002190969803300306 |s2cid=220925623 |issn=0021-9096 |url-access=subscription }}</ref><ref name="MicroB">{{Citation |last=Bajpai |first=Pratima |title=The Control of Microbiological Problems∗∗Some excerpts taken from Bajpai P (2012). Biotechnology for Pulp and Paper Processing with kind permission from Springer Science1Business Media. |date=2015 |journal=Pulp and Paper Industry |pages=103–195 |publisher=Elsevier |doi=10.1016/b978-0-12-803409-5.00008-2 |isbn=978-0-12-803409-5 |s2cid=89782614 |doi-access=free |pmc=7158184 }}</ref><ref name="Polym">{{Cite journal |date=December 2010 |title=BASF sells Intertech & Pira to the Smithers group |url=http://dx.doi.org/10.1016/s0969-6210(10)70272-1 |journal=Focus on Pigments |volume=2010 |issue=12 |pages=6–7 |doi=10.1016/s0969-6210(10)70272-1 |issn=0969-6210 |url-access=subscription }}</ref><ref>{{Citation |last=Hakkila |first=Pentti |chapter=Utilization of Residual Forest Biomass |date=1989 |chapter-url=http://dx.doi.org/10.1007/978-3-642-74072-5_8 |series=Springer Series in Wood Science |pages=352–477 |access-date=12 October 2023 |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |doi=10.1007/978-3-642-74072-5_8 |isbn=978-3-642-74074-9 }}</ref> * Non-wood pulp: This is a type of pulp that is made from non-wood materials, such as cotton, hemp, kenaf, linen, and bamboo. It is often used in high-quality papers, such as those used for art and photography.<ref name="SouthA"/><ref name="Polym"/><ref>{{Cite journal |last1=Coppola |first1=Floriana |last2=Fiorillo |first2=Flavia |last3=Modelli |first3=Alberto |last4=Montanari |first4=Matteo |last5=Vandini |first5=Mariangela |date=April 2018 |title=Effects of γ-ray treatment on paper |url=http://dx.doi.org/10.1016/j.polymdegradstab.2018.02.004 |journal=Polymer Degradation and Stability |volume=150 |pages=25–30 |doi=10.1016/j.polymdegradstab.2018.02.004 |issn=0141-3910 |url-access=subscription }}</ref>
Wood-free paper has a number of advantages over paper that contains mechanical pulp: * Wood-free paper is more resistant to yellowing because lignin, the main cause of paper yellowing, has been removed from the pulp.<ref name="MicroB"/><ref>{{Cite journal |last1=Wu |first1=Zonghua |last2=Tanaka |first2=Hiroo |date=April 1998 |title=Permanence of wood-free paper I: Paper-making additives in naturally degraded wood-free papers |journal=Journal of Wood Science |volume=44 |issue=2 |pages=111–115 |doi=10.1007/bf00526255 |s2cid=95493027 |issn=1435-0211 |doi-access=free |bibcode=1998JWSci..44..111W }}</ref><ref>{{Cite journal |last=BUKOVSKÝ |first=VLADIMÍR |date=1997 |title=Yellowing of Newspaper after Deacidification with Methyl Magnesium Carbonate |url=http://dx.doi.org/10.1515/rest.1997.18.1.25 |journal=Restaurator |volume=18 |issue=1 |doi=10.1515/rest.1997.18.1.25 |s2cid=96841775 |issn=0034-5806 |url-access=subscription }}</ref> * It is stronger because the cellulose fibers in wood-free paper are longer and more uniform than the fibers in mechanical pulp.<ref name="Nordic Pulp p297-305"/> * It is more durable because it is less likely to tear or crease.<ref name="Nordic Pulp p297-305"/> * It is smoother because its surface is more refined than that of paper containing mechanical pulp.<ref name="Nordic Pulp p297-305"/>
Wood-free paper is used in a variety of applications: * Writing and printing papers: Wood-free paper is the most common type of paper used for writing and printing.<ref name="Board">{{cite book |last=Tillmann |first=Otmar |date=20 January 2006 |chapter=Paper and Board Grades and Their Properties |chapter-url=http://dx.doi.org/10.1002/3527608257.ch11 |title=Handbook of Paper and Board |pages=446–466 |doi=10.1002/3527608257.ch11 |isbn=9783527309979 }}</ref> It is available in a variety of weights and finishes.<ref name="MicroB"/> * Envelopes: Wood-free paper is the most common type of paper used for envelopes.<ref>{{Cite journal |last1=Velebil |first1=J. |last2=Malaťák |first2=J. |last3=Bradna |first3=J. |date=31 December 2016 |title=Mass yield of biochar from hydrothermal carbonization of sucrose |journal=Research in Agricultural Engineering |volume=62 |issue=4 |pages=179–184 |doi=10.17221/73/2015-rae |issn=1212-9151 |doi-access=free }}</ref><ref>{{Cite thesis |title=An investigation of the factors affecting dot gain on sheet-fed offset lithography presses |publisher=Iowa State University |first=Yung-Cheng |last=Hsieh |date=1997 |doi=10.31274/rtd-180813-10494 |doi-access=free }}</ref> It is available in a variety of colors and finishes. * Art and photography papers: Wood-free paper is the most common type of paper used for art and photography.<ref name="Board"/> * Other applications: Wood-free paper is also used in a variety of other applications, such as packaging, labels, and currency<ref name="SouthA"/><ref>{{Citation |last=Hoekstra |first=Arjen Y. |title=The water footprint of industry |date=2015 |url=http://dx.doi.org/10.1016/b978-0-12-799968-5.00007-5 |work=Assessing and Measuring Environmental Impact and Sustainability |pages=221–254 |access-date=12 October 2023 |publisher=Elsevier |doi=10.1016/b978-0-12-799968-5.00007-5 |isbn=9780127999685 |url-access=subscription }}</ref> ==See also== * Coated fine paper
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Category:Printing and writing paper Category:Paper Category:Paper products