Editing Resin

{{Short description|Organic polymer, typically from plants}}
{{Other uses}}

[[File:Resin with insect (aka).jpg|thumb|right|[[Insect]] trapped in resin]]
[[File:Cedar of Lebanon cone.JPG|thumb|upright|[[Cedar of Lebanon]] cone showing flecks of resin as used in the [[mummification]] of [[Egyptian Pharaohs]] ]]

A '''resin''' is a solid or highly [[viscous]] liquid that can be converted into a [[polymer]].<ref name=":0">{{cite encyclopedia|title=Resin|encyclopedia=IUPAC Compendium of Chemical Terminology|publisher=International Union of Pure and Applied Chemistry|doi=10.1351/goldbook.RT07166|doi-access=free|year=2019|version=3.0.1|edition=3rd}}</ref> Resins may be biological or synthetic in origin, but are typically harvested from plants. Resins are mixtures of [[organic compound]]s, predominantly [[terpene]]s. Common resins include [[amber]], [[hashish]], [[frankincense]], [[myrrh]] and the animal-derived resin, [[shellac]]. Resins are used in [[varnish]]es, [[adhesive]]s, [[food additive]]s, [[incense]]s and [[perfume]]s.

Resins protect plants from insects and pathogens, and are secreted in response to injury. Resins repel [[herbivore]]s, insects, and pathogens, while the volatile [[natural phenol|phenolic compounds]] may attract benefactors such as predators of insects that attack the plant.<ref>{{cite book|title=Plant resins: Chemistry, evolution, ecology, and ethnobotany|author=Jean Langenheim|publisher=Timber Press|location=Portland, OR|date=2003|isbn=0881925748}}</ref>

== Composition ==
Most plant resins are composed of [[terpene]]s. Specific components are [[alpha-Pinene|alpha-pinene]], [[pinene|beta-pinene]], [[carene|delta-3 carene]], and [[sabinene]], the monocyclic terpenes [[limonene]] and [[terpinolene]], and smaller amounts of the tricyclic [[sesquiterpene]]s, [[longifolene]], [[caryophyllene]], and [[cadinene|delta-cadinene]]. Some resins also contain a high proportion of [[resin acid]]s.  [[Rosin]]s on the other hand are less volatile and consist of diterpenes among other compounds.{{citation needed|date=August 2015}}

=== Examples ===
Examples of plant resins include [[amber]], [[Balm of Gilead]], [[balsam]], [[Canada balsam]], [[copal]] from trees of ''[[Protium (plant)|Protium]] copal'' and ''[[Hymenaea courbaril]]'', [[dammar gum]] from trees of the family [[Dipterocarpaceae]], [[dragon's blood]] from the dragon trees (''[[Dracaena (plant)|Dracaena]]'' species), [[elemi]], [[frankincense]] from ''[[Boswellia sacra]]'', [[galbanum]] from ''[[Ferula gummosa]]'', [[gum guaicum|gum guaiacum]]<!--(the article name is surely a spelling error in this title?) --> from the [[lignum vitae]] trees of the genus ''[[Guaiacum]]'', [[kauri gum]] from trees of ''[[Agathis australis]]'', [[hashish]] (Cannabis resin) from ''[[Cannabis indica]]'', [[labdanum]] from mediterranean species of ''[[Cistus]]'', [[mastic (plant resin)]] from the mastic tree ''[[Pistacia lentiscus]]'', [[myrrh]] from shrubs of ''[[Commiphora]]'', [[sandarac]] resin from ''[[Tetraclinis articulata]]'', the national tree of Malta, [[styrax#uses of resin|styrax]] (a [[Benzoin resin]] from various ''[[Styrax]]'' species) and [[spinifex resin]] from Australian grasses.

[[Amber]] is [[fossil]] resin (also called resinite) from coniferous and other tree species. Copal, kauri gum, dammar and other resins may also be found as subfossil deposits. Subfossil copal can be distinguished from genuine fossil amber because it becomes tacky when a drop of a solvent such as [[acetone]] or [[chloroform]] is placed on it.<ref>David Grimaldi, ''Amber: Window to the Past'', 1996, p 16-20, American Museum of Natural History</ref>
African [[copal]] and the kauri gum of New Zealand are also procured in a semi-fossil condition.

=== Rosin ===
{{see also|Rosin}}
[[File:Araucaria Resin.JPG|thumb|right|Extremely [[Viscosity|viscous]] resin extruding from the trunk of a mature ''[[Araucaria columnaris]]''.]]

[[Rosin]] is a solidified resin from which the [[Volatility (chemistry)|volatile]] [[terpene]]s have been removed by distillation. Typical rosin is a transparent or translucent mass, with a vitreous fracture and a faintly yellow or brown colour, non-odorous or having only a slight turpentine odour and taste. Rosin is insoluble in water, mostly soluble in alcohol, [[essential oil]]s, [[diethyl ether|ether]], and hot fatty oils.  Rosin softens and melts when heated and burns with a bright but smoky flame.

Rosin consists of a complex mixture of different substances including organic acids named the [[resin acid]]s. Related to the terpenes, resin acid is [[oxidation|oxidized]] terpenes. Resin acids dissolve in [[alkali]]s to form [[resin soap]]s, from which the resin acids are regenerated upon treatment with acids. Examples of resin acids are [[abietic acid]] (sylvic acid), C<sub>20</sub>H<sub>30</sub>O<sub>2</sub>, [[plicatic acid]] contained in cedar, and [[pimaric acid]], C<sub>20</sub>H<sub>30</sub>O<sub>2</sub>, a constituent of [[galipot]] resin. Abietic acid can also be extracted from rosin by means of hot alcohol. 

Rosin is obtained from [[pine]]s and some other [[plant]]s, mostly [[Pinophyta|conifers]].<ref name=Ullmann>{{cite encyclopedia|doi=10.1002/14356007.a23_073 |chapter=Resins, Natural |encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry |year=2000 |last1=Fiebach |first1=Klemens |last2=Grimm |first2=Dieter |isbn=978-3-527-30673-2|publisher=Wiley-VCH|location=Weinheim}}</ref> Plant resins are generally produced as stem secretions, but in some Central and South American species of ''[[Dalechampia]]'' and ''[[Clusia]]'' they are produced as pollination rewards, and used by some [[stingless bee]] species in nest construction.<ref>{{cite journal | first1=V. | last1=Bittrich | first2= Maria C. E. | last2= Amaral | year=1996 | title=Flower morphology and pollination biology of some Clusia species from the Gran Sabana (Venezuela) | journal=Kew Bulletin | volume=51 | issue=4 | pages=681–694 | doi=10.2307/4119722| jstor=4119722 | bibcode=1996KewBu..51..681B }}</ref><ref>{{cite journal | first=Silmary de Jesus | last= Gonçalves-Alvim |year=2001 | title=Resin-collecting bees (Apidae) on Clusia palmicida (Clusiaceae) in a riparian forest in Brazil | journal=Journal of Tropical Ecology | volume=17 | issue=1 | pages=149–153 | doi=10.1017/s0266467401001092| s2cid= 85842020 }}</ref> [[Propolis]], consisting largely of resins collected from plants such as [[poplars]] and [[conifer]]s, is used by [[honey bee]]s to seal small gaps in their hives, while larger gaps are filled with beeswax.<ref name=Finstrom>{{cite journal|last1=Simone-Finstrom|first1=M.|last2=Spivak|first2=M.|year=2010|title=Propolis and bee health: The natural history and significance of resin use by honey bees|journal=Apidologie|volume=41|issue=3|pages=295–311|doi=10.1051/apido/2010016|s2cid=15828725|url=https://link.springer.com/content/pdf/10.1051/apido/2010016.pdf|doi-access=free}}</ref>

===Petroleum- and insect-derived resins===
[[Shellac]] is an example of an insect-derived resin.

[[Asphaltite]] and Utah resin are petroleum [[bitumen]]s.

==History and etymology==
[[File:Resin on Almond tree.jpg|thumb|right|The material dripping from an almond tree looks confusingly like resin, but actually is a [[Natural gum|gum]] or [[mucilage]], and chemically very different.]]
Human use of plant resins has a long history that was documented in [[ancient Greece]] by [[Theophrastus]], in ancient Rome by [[Pliny the Elder]], and especially in the resins known as [[frankincense]] and [[myrrh]], prized in [[ancient Egypt]].<ref name="ancegy">{{cite web|url=http://ocean.tamu.edu/Quarterdeck/QD3.1/Elsayed/elsayedhatshepsut.html|title=Queen Hatshepsut's expedition to the Land of Punt: The first oceanographic cruise?|publisher=Dept. of Oceanography, Texas A&M University|access-date=2010-05-08|archive-date=2014-08-14|archive-url=https://web.archive.org/web/20140814154851/http://ocean.tamu.edu/Quarterdeck/QD3.1/Elsayed/elsayedhatshepsut.html|url-status=dead}}</ref> These were highly prized substances, and required as [[incense]] in some religious rites.

The word ''resin'' comes from French ''resine'', from Latin ''resina'' "resin", which either derives from or is a [[cognate]] of the Greek {{lang|grc|ῥητίνη}} ''rhētínē'' "resin of the pine", of unknown earlier origin, though probably non-[[Indo-European languages|Indo-European]].<ref>{{cite web|title=resin, n. and adj.|url=http://www.oed.com/view/Entry/163629|website=OED Online|publisher=Oxford University Press|access-date=2 December 2014|date=September 2014}}</ref><ref>{{cite web|title=resin (n.)|url=http://www.etymonline.com/index.php?term=resin|website=Online Etymology Dictionary|access-date=2 December 2014}}</ref>

The word "resin" has been applied in the modern world to nearly any component of a liquid that will set into a hard [[lacquer]] or [[Vitreous enamel|enamel]]-like finish. An example is nail polish. Certain "casting resins" and [[synthetic resin]]s (such as [[epoxy resin]]) have also been given the name "resin".

Some naturally-derived resins, when soft, are known as 'oleoresins', and when containing [[benzoic acid]] or [[cinnamic acid]] they are called balsams. Oleoresins are naturally-occurring mixtures of an oil and a resin; they can be extracted from various plants. Other resinous products in their natural condition are a mix with [[natural gum|gum]] or mucilaginous substances and known as [[gum resin]]s.  Several natural resins are used as ingredients in perfumes, e.g., balsams of Peru and tolu, elemi, styrax, and certain turpentines.<ref name=Ullmann/>

===Non-resinous exudates===
Other liquid compounds found inside plants or exuded by plants, such as [[Plant sap|sap]], [[latex]], or [[mucilage]], are sometimes confused with resin but are not the same. Saps, in particular, serve a nutritive function that resins do not.

[[File:Résine.jpg|thumb|Resin of  pine]]

==Uses==
===Plant resins===
Plant resins are valued for the production of [[varnish]]es, [[adhesive]]s, and food [[glazing agent]]s. They are also prized as raw materials for the [[organic synthesis|synthesis of other organic compounds]] and provide constituents of [[incense]] and [[perfume]]. The oldest known use of plant resin comes from the late Middle Stone Age in Southern Africa where it was used as an adhesive for hafting stone tools.<ref>{{Cite journal|last1=Kozowyk|first1=P. R. B.|last2=Langejans|first2=G. H. J.|last3=Poulis|first3=J. A.|date=2016-03-16|title=Lap Shear and Impact Testing of Ochre and Beeswax in Experimental Middle Stone Age Compound Adhesives|journal=PLOS ONE|volume=11|issue=3|pages=e0150436|doi=10.1371/journal.pone.0150436|pmid=26983080|pmc=4794155|bibcode=2016PLoSO..1150436K|issn=1932-6203|url=https://repository.tudelft.nl/islandora/object/uuid%3A8e8d5540-1d0f-4f84-8d86-932d8a8af5e1/datastream/OBJ/download|doi-access=free}}</ref>

[[Image:Frankincense 2005-12-31.jpg|thumb|Lumps of dried [[frankincense]] resin]]
[[File:Protium Sp. MHNT.BOT.2016.24.54.jpg|thumb|[[Caranna]], a hard, brittle, resinous gum from species of ''Protium'']]

The hard transparent resins, such as the copals, [[dammar]]s, [[Mastic (plant resin)|mastic]], and [[sandarac]], are principally used for varnishes and adhesives, while the softer odoriferous oleo-resins ([[frankincense]], [[elemi]], [[turpentine]], [[copaiba]]), and gum resins containing essential oils ([[ammoniacum]], [[asafoetida]], [[gamboge]], [[myrrh]], and [[scammony]]) are more used for  food and [[incense]].{{cn|date=March 2025}}  The resin of the [[Aleppo pine]] is used to flavor [[retsina]], a Greek [[resinated wine]].<ref>{{cite web|url=http://www.fao.org/docrep/x0453e/x0453e10.htm|title=Non-wood forest products from conifers - CHAPTER 6|website=www.fao.org|access-date=2015-06-18|archive-date=2015-06-19|archive-url=https://web.archive.org/web/20150619120550/http://www.fao.org/docrep/x0453e/x0453e10.htm|url-status=dead}}</ref>

===Animal resins===
While animal resins are not as common as either plant or synthetic resins some animal resins like [[lac (resin)|lac]] (obtained from ''[[Kerria lacca]]'') are used for applications like [[sealing wax]] in [[India]],<ref name=indiapost1>[https://www.itokri.com/pages/the-art-of-sealing "The art of sealing."]</ref> and [[lacquerware]] in [[Sri Lanka]].{{citation needed|date=March 2024}}

===Synthetic resins===
{{main|Synthetic resin}}
Many materials are produced via the conversion of synthetic resins to solids, such as [[bisphenol A diglycidyl ether]] &ndash; a resin converted to [[epoxy glue]] upon the addition of a hardener.  Silicones are often prepared from silicone resins via [[RTV silicone|room temperature vulcanization]]. [[Alkyd resin]]s are used in [[paint]]s and [[varnish]]es and harden or cure by exposure to [[oxygen]] in the air.<ref>{{Cite web|date=2016-03-29|title=Basics of Alkyd Resin Technology|url=https://chemicaldynamics.net/2016/03/29/basics-alkyd-resin-technology|url-status=live|website=Chemical Dynamics|archive-url=https://web.archive.org/web/20210514151428/https://chemicaldynamics.net/2016/03/29/basics-alkyd-resin-technology |archive-date=2021-05-14 }}</ref>

==See also==
* {{annotated link|Amber}}
* {{annotated link|Balsam of Peru}}
* {{annotated link|Biodegradable}} – plant resins are naturally biodegradable in many circumstances.
* {{annotated link|Kino (gum)}}
* {{annotated link|Mastic (plant resin)}}
* {{annotated link|Pitch (resin)}}
* {{annotated link|Polyresin}}
* {{annotated link|Resin casting}}
* {{annotated link|Resin extraction}}

==References==
{{reflist}}

== External links ==
* {{Wiktionary-inline|resin}}
* {{Commons-inline|Resin}}

{{Non-timber forest products}}
{{Paper}}

{{Authority control}}

[[Category:Resins| ]]
[[Category:Non-timber forest products]]
[[Category:Papermaking]]
[[Category:Tree tapping]]