In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers.Resins are usually mixtures of organic compounds. This article focuses on naturally occurring resins.
Plants secrete resins for their protective benefits in response to injury. The resin protects the plant from insects and pathogens.Resins confound a wide range of herbivores, insects, and pathogens, while the volatile phenolic compounds may attract benefactors such as parasitoids or predators of the herbivores that attack the plant.
Most plant resins are composed of terpenes. Specific components are alpha-pinene, beta-pinene, delta-3 carene, and sabinene, the monocyclic terpenes limonene and terpinolene, and smaller amounts of the tricyclic sesquiterpenes, longifolene, caryophyllene, and delta-cadinene. Some resins also contain a high proportion of resin acids. Rosins on the other hand are less volatile and consist of diterpenes among other compounds.[ citation needed ]
Examples of plant resins include amber, Balm of Gilead, balsam, Canada balsam, Boswellia, copal from trees of Protium copal and Hymenaea courbaril , dammar gum from trees of the family Dipterocarpaceae, Dragon's blood from the dragon trees ( Dracaena species), elemi, frankincense from Boswellia sacra , galbanum from Ferula gummosa , gum guaiacum 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 (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.African copal and the kauri gum of New Zealand are also procured in a semi-fossil condition.
Rosin is a solidified resin from which the volatile terpenes 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 oils, 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 acids. Related to the terpenes, resin acid is oxidized terpenes. Resin acids dissolve in alkalis to form resin soaps, from which the resin acids are regenerated upon treatment with acids. Examples of resin acids are abietic acid (sylvic acid), C20H30O2, plicatic acid contained in cedar, and pimaric acid, C20H30O2, a constituent of galipot resin. Abietic acid can also be extracted from rosin by means of hot alcohol. Pimaric acid closely resembles abietic acid into which it passes when distilled in a vacuum; it has been supposed to consist of three isomers.[ by whom? ]
Rosin is obtained from pines and some other plants, mostly conifers.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. Propolis, consisting largely of resins collected from plants such as poplars and conifers, is used by honey bees to seal small gaps in their hives, while larger gaps are filled with beeswax.
Shellac is an example of an insect-derived resin.
Asphaltite and Utah resin are petroleum bitumens.
Human use of plant resins has a very 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.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 ῥητίνηrhētínē "resin of the pine", of unknown earlier origin, though probably non-Indo-European.
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 enamel-like finish. An example is nail polish. Certain "casting resins" and synthetic resins (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 gum or mucilaginous substances and known as gum resins. Several natural resins are used as ingredients in perfumes, e.g., balsams of Peru and tolu, elemi, styrax, and certain turpentines.
Other liquid compounds found inside plants or exuded by plants, such as 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.
Plant resins are valued for the production of varnishes, adhesives, and food glazing agents. They are also prized as raw materials for the 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.
The hard transparent resins, such as the copals, dammars, 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 therapeutic purposes, food and incense. The resin of the Aleppo Pine is used to flavour retsina, a Greek resinated wine.
Many materials are produced via the conversion of synthetic resins to solids. Important examples are bisphenol A diglycidyl ether, which is a resin converted to epoxy glue upon the addition of a hardener. Silicones are often prepared from silicone resins via room temperature vulcanization.
Myrrh is a gum-resin extracted from a number of small, thorny tree species of the genus Commiphora. Myrrh resin has been used throughout history as a perfume, incense and medicine. Myrrh mixed with posca or wine was common across ancient cultures, for general pleasure, and as an analgesic.
Turpentine is a fluid obtained by the distillation of resin harvested from living trees, mainly pines. Mainly used as a specialized solvent, it is also a source of material for organic syntheses.
Varnish is a clear transparent hard protective coating or film. It is not a stain. When manufactured it is not water-white because of the processing and materials used. It usually has a yellowish shade, but it may be pigmented as desired, and is sold commercially in various shades.
Frankincense is an aromatic resin used in incense and perfumes, obtained from trees of the genus Boswellia in the family Burseraceae, particularly Boswellia sacra, B. carterii, B. frereana, B. serrata, and B. papyrifera. The word is from Old French franc encens.
Rosin, also called colophony or Greek pitch, is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black. At room temperature rosin is brittle, but it melts at stove-top temperature. It chiefly consists of various resin acids, especially abietic acid. The term "colophony" comes from colophonia resina, Latin for 'resin from Colophon', an ancient Ionic city.
Abietic acid is an organic compound that occurs widely in trees. It is the primary component of resin acid, is the primary irritant in pine wood and resin, isolated from rosin and is the most abundant of several closely related organic acids that constitute most of rosin, the solid portion of the oleoresin of coniferous trees. Its ester or salt is called an abietate.
Balsam is the resinous exudate which forms on certain kinds of trees and shrubs. Balsam owes its name to the biblical Balm of Gilead.
Canada balsam, also called Canada turpentine or balsam of fir, is a turpentine made from the resin of the balsam fir tree of boreal North America. The resin, dissolved in essential oils, is a viscous, sticky, colourless or yellowish liquid that turns to a transparent yellowish mass when the essential oils have been allowed to evaporate.
Dammar, also called dammar gum, or damar gum, is a resin obtained from the tree family Dipterocarpaceae in India and East Asia, principally those of the genera Shorea or Hopea. Most is produced by tapping trees; however, some is collected in fossilised form on the ground. The gum varies in colour from clear to pale yellow, while the fossilised form is grey-brown. Dammar gum is a triterpenoid resin, containing many triterpenes and their oxidation products. Many of them are low molecular weight compounds, but dammar also contains a polymeric fraction, composed of polycadinene. The name dammar is a Malay word meaning ‘resin’ or ‘torch made from resin’.
Onycha, along with equal parts of stacte, galbanum, and frankincense, was one of the components of the consecrated Ketoret (incense) which appears in the Torah book of Exodus (Ex.30:34-36) and was used in the Jerusalem's Solomon's Temple. This formula was to be incorporated as an incense, and was not to be duplicated for non-sacred use. What the onycha of antiquity actually was cannot be determined with certainty. The original Hebrew word used for this component of the ketoret was שחלת, shecheleth, which means "to roar; as a lion " or “peeling off by concussion of sound." Shecheleth is related to the Syriac shehelta which is translated as “a tear, distillation, or exudation.” In Aramaic, the root SHCHL signifies “retrieve.” When the Torah was translated into Greek the Greek word “onycha” ονυξ, which means "fingernail" or "claw," was substituted for shecheleth.
Styrax is a genus of about 130 species of large shrubs or small trees in the family Styracaceae, mostly native to warm temperate to tropical regions of the Northern Hemisphere, with the majority in eastern and southeastern Asia, but also crossing the equator in South America. The resin obtained from the tree is called benzoin or storax.
Benzoin or benjamin is a balsamic resin obtained from the bark of several species of trees in the genus Styrax. It is used in perfumes and some kinds of incense and as a flavoring and medicine. It is distinct from the chemical compound benzoin, which is ultimately derived chemically from benzoin resin; the resin, however, does not contain this compound.
The Burseraceae are a moderate-sized family of 17-19 genera and about 540 species of flowering plants. The actual numbers differ according to the time period in which a given source is written describing this family. The Burseraceae are also known as the torchwood family, the frankincense and myrrh family, or simply the incense tree family. The family includes both trees and shrubs, and is native to tropical regions of Africa, Asia. Australasia, and the Americas.
Storax, often commercially sold as styrax, is a natural resin isolated from the wounded bark of Liquidambar orientalis Mill. and Liquidambar styraciflua L. (Hamamelidaceae). It is distinct from benzoin, a similar resin obtained from the Styracaceae plant family.
The genus of the myrrhs, Commiphora, is the most species-rich genus of flowering plants in the frankincense and myrrh family, Burseraceae. The genus contains approximately 190 species of shrubs and trees, which are distributed throughout the (sub-) tropical regions of Africa, the western Indian Ocean islands, the Arabian Peninsula, India, and Vietnam. The genus is drought-tolerant and common throughout the xerophytic scrub, seasonally dry tropical forests, and woodlands of these regions.
Kauri gum is a fossilised resin extracted from kauri trees, which is made into crafts such as jewellery. Kauri forests once covered much of the North Island of New Zealand, before the arrival of people caused deforestation, causing several areas to revert to sand dunes, scrubs, and swamps. Even afterward, ancient kauri fields continued to provide a source for the gum and the remaining forests.
Gum base is the non-nutritive, non-digestible, water-insoluble masticatory delivery system used to carry sweeteners, flavors, and any other substances in chewing gum and bubble gum. It provides all the basic textural and masticatory properties of gum.
Stacte and nataph are names used for one component of the Solomon's Temple incense, the Ketoret, specified in the Book of Exodus. Variously translated to the Greek term or to an unspecified "gum resin" or similar, it was to be mixed in equal parts with onycha, galbanum and mixed with pure frankincense and they were to "beat some of it very small" for burning on the altar of the tabernacle.
Levopimaric acid is an abietane-type of diterpene resin acid. It is a major constituent of pine oleoresin with the chemical formula of C20H30O2. In general, the abietene types of diterpene resin acid have various biological activities, such as antibacterial, cardiovascular and antioxidant. About 18 to 25% of levopimaric acid is found in pine oleoresin. The production of oleoresin by conifer species is an important component of the defense response against insect attack and fungal pathogen infection.
The incense offering, a blend of aromatic substances that exhale perfume during combustion, usually consisting of spices and gums burnt as an act of worship, occupied a prominent position in the sacrificial legislation of the ancient Hebrews.