Editing Particle board

{{Short description|Glued wood product}}
{{Refimprove|article|date=November 2007}}
[[File:Particleboard.jpg|right|thumb|Particleboard with [[Wood veneer|veneer]]]]

'''Particle board''', also known as '''particleboard''' or '''chipboard''', is an [[engineered wood]] product, belonging to the wood-based panels, manufactured from [[wood chips]] and a synthetic, mostly formaldehyde-based [[resin]] or other suitable binder, which is pressed under a hot press, batch- or continuous- type, and produced.<ref>{{Cite web |title=Wood based panel producers in Poland |url=http://sppd.pl/en/mdf,-ldf,-hdf.html |publisher=sppd.pl}}</ref> Particle board is often confused with [[oriented strand board]] (OSB, also known as flakeboard, or waferboard), a different type of [[fiberboard]] that uses machined wood flakes and offers more strength.

== Characteristics ==
[[File:Particle_board-cross_section_scan.jpg|thumb|Cross section of a particle board]]
Particle board is cheaper, [[Density|denser]], and more uniform than conventional wood and [[plywood]] and is substituted for them when cost is more important than strength and appearance. Particleboard can be made more appealing by painting or the use of wood [[Veneer (wood)|veneers]] on visible surfaces. Though it is denser than conventional wood, it is the lightest and weakest type of fiberboard, except for insulation board. [[Medium-density fibreboard]] and [[hardboard]], also called high-density fiberboard, are stronger and denser than particleboard. Different grades of particleboard have different densities, with higher density connoting greater strength and greater resistance to failure of screw fasteners.

A significant disadvantage of particleboard is its susceptibility to expansion and discoloration from moisture absorption, particularly when it is not covered with [[paint]] or another sealer. Therefore, it is rarely used outdoors or in places where there are high levels of moisture, except in bathrooms, kitchens and laundries, where it is commonly used as an underlayment shielded beneath a moisture-resistant continuous sheet of [[Polyvinyl chloride|vinyl]] flooring.

In dry environments, veneered particleboard is preferred over veneered plywood because of its stability, lower cost, and convenience.

== History and development ==
The history of particleboard is unclear. The nineteenth century saw many attempts to make use of sawmill by-products, including sawdust and wood chips, by manufacturing composite boards; conceptual references to processes of manufacturing wood composites similar to particleboard date from 1887.<ref>{{cite journal |last1=Katlan |first1=Alexander W. |title=Early Wood-Fiber Panels: Masonite, Hardboard, and Lower-Density Boards |journal=Journal of the American Institute for Conservation |date=1994 |volume=33 |issue=3 |pages=301–306 |doi=10.2307/3179639 |jstor=3179639 |url=https://doi.org/10.2307/3179639|url-access=subscription }}</ref> In 1935, Farley and Loetscher Manufacturing Co. became the first plant to manufacture particleboard.<ref>{{cite journal |last1=Bucher |first1=Charles |title=Dating Twentieth-Century Buildings by Means of Construction Materials |journal=APT Bulletin: The Journal of Preservation Technology |date=2012 |volume=43 |issue=2/3 |page=75 |jstor=23317191 |url=http://www.jstor.org/stable/23317191}}</ref> A particleboard industry developed over the course of the 1940s.<ref>{{cite book|last1=Rowell M.|first1=Roger|url=https://books.google.com/books?id=Kn_RBQAAQBAJ|title=Handbook of Wood Chemistry and Wood Composites|date=2005|publisher=Taylor and Francis Group|isbn=978-1-4398-5381-8}}</ref>

In 1932, ''[[Luftwaffe]]'' pilot and inventor [[Max Himmelheber]] patented a process for making particleboard without fully impregnating wood fibers with adhesive, distinguishing it from earlier wood composites.<ref>{{Cite web|url=https://patents.google.com/patent/CH182058A/en|title = Wood-like mass and process for its production}}</ref> This particleboard could be produced with waste products such as planer shavings, off-cuts, or sawdust, [[Hammermill|hammer-milled]] into chips and bound together with a [[phenolic resin]]. Hammer-milling involves smashing material into smaller and smaller pieces until they can pass through a screen. Most early particleboard manufacturers used similar processes, though often with slightly different resins. 

It was found that better strength, appearance, and resin economy could be achieved by using more uniform, manufactured chips. Producers began processing solid [[birch]], [[beech]], [[alder]], [[pine]], and [[spruce]] into consistent chips and flakes; these finer layers were then placed on the outside of the board, with its core composed of coarser, cheaper chips. This type of board is known as three-layer particleboard.

More recently,{{When|date=February 2020}} graded-density particleboard has also evolved. It contains particles that gradually become smaller as they get closer to the surface.

== Manufacturing ==
[[File:Particle_board_manufacturing_process.jpg|alt=Particle board manufacturing process|thumb|Jute-stick Particle board manufacturing process]]
Particleboard or chipboard is manufactured by mixing particles or flakes of wood or [[Jutestick|jute-stick]] together with a [[resin]] and forming the mixture into a sheet. The raw material is fed into a [[Wood chipper#Disc|disc chipper]] with between four and sixteen radially arranged blades. The chips from disk chippers are more uniform in shape and size than from other types of wood chippers. The particles are then dried, and any oversize or undersized particles are screened out.

[[Resin]] is then sprayed as a fine mist onto the particles. Several types of resins are used in the process.<ref>{{cite journal | last1=[[George Mantanis|Mantanis]] | first1=George I. | last2=Athanassiadou | first2=Eleftheria Th. | last3=Barbu | first3=Marius C. | last4=Wijnendaele | first4=Kris | title=Adhesive systems used in the European particleboard, MDF and OSB industries | journal=Wood Material Science & Engineering | volume=13 | issue=2 | date=2018-03-15 | issn=1748-0272 | doi=10.1080/17480272.2017.1396622 | pages=104–116}}</ref> Amino-formaldehyde-based resins are the best-performing based on cost and ease of use. Urea [[Melamine resin|melamine resins]] offer water resistance, with more melamine offering higher resistance. It is typically used in external applications, with the coloured resin darkening the panel. To further enhance the panel properties, [[resorcinol]] resins can be mixed with [[phenolic resins]], but that is more often used with [[marine plywood]] applications.

Panel production involves other chemicals including [[wax]], dyes, wetting agents, and release agents, to aid processing or make the final product resistant to water, fire, or insects.

After the particles pass through a mist of resin sufficient to coat all surfaces, they are layered into a continuous "carpet". This carpet is then separated into discrete, rectangular "blankets" which will be compacted in a cold press. A [[Weighing scale|scale]] weighs the flakes, and they are distributed by rotating rakes. In graded-density particleboard, the flakes are spread by an air jet that throws finer particles further than coarse ones. Two such jets, reversed, allow the particles to build up from fine to coarse and back to fine.

The formed sheets are cold-compressed to reduce thickness and make them easier to transport. Later, they are compressed again, under pressures between {{convert|2|and|3|MPa|psi}} and temperatures between {{convert|140|and|220|°C|°F}} to set and harden the glue. The entire process is controlled to ensure the correct size, density, and consistency of the board.

The boards are then cooled, trimmed, and sanded. They can then be sold as raw board or surface-improved through the addition of a wood veneer or laminate surface.

== Furniture design ==
[[File:Конфирмат.JPG|thumb|[[Confirmat screw]]s on particleboard, in which they were designed to hold. They are still widely used in particleboard furniture.]]
{{seealso|flat pack furniture}}Particle board has had a huge influence on furniture design. In the early 1950s, particle-board kitchens started to come into use in furniture construction but, in many cases, it remained more expensive than solid wood. A particle-board kitchen was only available to the very wealthy.{{Citation needed|date=September 2009}} Once the technology was more developed, particle board became cheaper.

Some large companies base their strategies around providing furniture at a low price. To do this, they use the least expensive materials possible. In almost all cases, this means particle board, [[medium-density fibreboard]] (MDF), or the like. However, in order to maintain a reputation for quality at low cost, manufacturers may use higher grades of particle board, e.g., higher-density particle board, thicker particle board, or particle board using higher-quality resins. One may note the amount of sag in a shelf of a given width in order to draw the distinction.

In general, the much lower cost of sheet goods (particle board, medium density fiberboard, and other engineered wood products) has helped to displace solid wood from many cabinetry applications.

== Safety ==
Safety concerns exist for both manufacturing and use. Fine dust and chemicals are released when particleboard is machined (e.g., sawing or [[Router (woodworking)|routing]]). Occupational exposure limits exist in many countries recognizing the hazard of wood dusts.<ref name="HSE, wis12">{{cite web|title=Wood dust hazards|url=http://www.hse.gov.uk/pubns/wis1.pdf|url-status=dead|archive-url=https://web.archive.org/web/20091229103016/http://www.hse.gov.uk/pubns/wis1.pdf|archive-date=2009-12-29|publisher=UK HSE}}</ref> Cutting particle board can release [[formaldehyde]], [[carbon monoxide]], [[hydrogen cyanide]] in the case of [[Amino resin|amino resins]], and [[phenol]] in the case of [[phenol formaldehyde resin]]s.<ref>{{cite web|last1=McCann|first1=Michael|last2=Babin|first2=Angela|date=1995|title=Certified Master Woodworker|url=https://thetedswoodworkingreview.com/teds-woodworking-review/|access-date=June 19, 2019|website=The University of Illinois at Chicago}}</ref>

The other safety concern is the slow release of formaldehyde over time. In 1984, concerns about the high indoor levels of formaldehyde in new [[manufactured home]]s led the [[United States Department of Housing and Urban Development]] to set construction standards. Particleboard (PB), medium-density fibreboard (MDF), oriented strand board (OSB), and laminated flooring have been major sources of formaldehyde emissions. In response to consumer and woodworker pressure on the industry, PB and MDF became available in "no added formaldehyde" (NAF) versions, but were not in common use {{asof|2015|lc=yes}}. Many other building materials such as furniture finish, carpeting, and caulking give off formaldehyde, as well as [[urea-formaldehyde foam insulation]], which is banned in Canada for installation in a residential closed-cavity wall.<ref>{{cite web|title=Formaldehyde Factsheet|url=http://www.idph.state.il.us/envhealth/factsheets/formaldehyde.htm|publisher=Illinois Department of Public Health|format=webpage}}</ref> Formaldehyde is classified by the [[WHO]] as a known human [[carcinogen]].<ref name="International Agency for Research on Cancer, Monographs Vol 882">{{Citation|title=IARC Monographs on the Evaluation of Carcinogenic Risks to Humans Volume 88 (2006) Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol|url=http://monographs.iarc.fr/ENG/Monographs/vol88/index.php|publisher=WHO Press, 2006( English )|format=pdf, html}}</ref>

== See also ==
* [[Confirmat screw]]s are designed to hold in particleboard
* [[Fiberboard]]
* [[Glued laminated timber]]
* [[Haskelite]]
* [[Masonite]]
* [[Pressed wood]]
* [[Waferboard]]

==References==
{{Reflist}}

==External links==
{{Wiktionary}}

* [http://www.decorativesurfaces.org/products/particleboard.html Composite Panel Association: Particleboard] {{Webarchive|url=https://web.archive.org/web/20131110033051/http://www.decorativesurfaces.org/products/particleboard.html |date=2013-11-10 }}
* [https://web.archive.org/web/20181015112650/http://europanels.org/products--producers/products/particleboard European Panel Federation: Particleboard]
{{Wood products}}{{Woodworking}}{{Authority control}}
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[[Category:Composite materials]]
[[Category:Woodworking materials]]
[[Category:Engineered wood]]
[[Category:German inventions of the Nazi period]]
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