resin

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resin,

any of a class of amorphous solids or semisolids. Resins are found in nature and are chiefly of vegetable origin. They are typically light yellow to dark brown in color; tasteless; odorless or faintly aromatic; translucent or transparent; brittle, fracturing like glass; and flammable, burning with a smoky flame. Resins are soluble in alcohol, ether, and many hydrocarbons but are insoluble in water. When heated, they soften and finally melt. Their chemical composition varies, but most are mixtures of organic acids and esters. Resins are generally classified according to their source or by such qualities as hardness or solubility. Natural resins are found as exudations, often as globules or tears, on the bark of various trees (mostly pines and firs) or on other living plants; they also occur as fossils or as exudations from the bodies of certain scale insects (see laclac,
resinous exudation from the bodies of females of a species of scale insect (Tachardia lacca), from which shellac is prepared. India is the chief source of shellac, although some is obtained from other areas in Southeast Asia.
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). Some natural resins, called oleoresins, contain both a resin and an essential oil; they are often viscid, sticky, gummy, or plastic. Other resins are exceedingly hard and resistant to most solvents, softening only at high temperatures. The primary uses for most resins are in varnish, shellac, and lacquer, in medicine, in molded articles (e.g., pipe mouthpieces), and in electrical insulators. See amberamber,
fossilized tree resin. Amber can vary in color from yellow to red to green and blue. The best commercial amber is transparent, but some varieties are cloudy. To be called amber, the resin must be several million years old; recently hardened resins are called copals.
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; balsambalsam
, fragrant resin obtained from various trees. The true balsams are semisolid and insoluble in water, but they are soluble in alcohol and partly so in hydrocarbons.
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; benzoinbenzoin
or benzoinum
, balsamic resin, the dried exudation from the pierced bark of various species of the benzoin tree (Styrax) native to Sumatra, Java, and Thailand; appearing as red-brown to yellow-brown tears.
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; Canada balsamCanada balsam,
yellow, oily, resinous exudation obtained from the balsam fir. It is an oleoresin (see resin) with a pleasant odor but a biting taste. It is a turpentine rather than a true balsam.
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; copaibacopaiba
, oleoresin (see resin) obtained from several species of tropical South American trees of the genus Copaifera. The thick, transparent exudate varies in color from light gold to dark brown, depending on the ratio of resin to essential oil.
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; dragon's blooddragon's blood,
name for a red resin obtained from a number of different plants. It was held by early Greeks, Romans, and Arabs to have medicinal properties; Dioscorides and other early writers described it.
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; masticmastic,
resin obtained from the small mastic tree Pistacia lentiscus (of the sumac family), found chiefly in Mediterranean countries. When the bark of the tree is injured, the resin exudes in drops. It is transparent and pale yellow to green in color.
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; rosinrosin
or colophony,
hard, brittle, translucent resin, obtained as a solid residue from crude turpentine. Usually pale yellow or amber, its color may vary from brownish-black to transparent depending on the nature of the source of the crude turpentine.
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; turpentineturpentine,
yellow to brown semifluid oleoresin exuded from the sapwood of pines, firs, and other conifers. It is made up of two principal components, an essential oil and a type of resin that is called rosin.
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resin

[′rez·ən]
(organic chemistry)
Any of a class of solid or semisolid organic products of natural or synthetic origin with no definite melting point, generally of high molecular weight; most resins are polymers.

resin

A nonvolatile solid or semisolid organic material, usually of high molecular weight; obtained as gum from certain trees or manufactured synthetically; tends to flow when subjected to heat or stress; soluble in most organic solvents but not in water; the film-forming component of a paint or varnish; used in making plastics and adhesives.

resin

1. any of a group of solid or semisolid amorphous compounds that are obtained directly from certain plants as exudations. They are used in medicine and in varnishes
2. any of a large number of synthetic, usually organic, materials that have a polymeric structure, esp such a substance in a raw state before it is moulded or treated with plasticizer, stabilizer, filler, etc