page_title: Resin
section_title: Rosin
hierarchical_section_title: Resin / Composition / Rosin
caption_attribution_description: English: Resin extruding from trunk of mature Araucaria Columnaris at Hooghly near Bandel in West Bengal, India.
context_page_description: 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.
  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.
context_section_description: 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.
  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 such as Euphorbia dalechampia and Clusia species  they are produced as pollination rewards, and used by some stingless bee species to construct their nests. 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.
caption: Extremely viscous resin extruding from the trunk of a mature Araucaria columnaris.
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