Natural Resin


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Resin, Natural

 

any of the solid substances possessing various degrees of transparency and color (from colorless to dark brown) contained in resiniferous plants. Natural resins are obtained from fluids (soft resins) that are secreted from the surface of plants either spontaneously or as a result of piercing (tapping). Some natural resins, which are called fossil or semi-fossil resins, are obtained from deposits in the ground.

Natural resins melt upon heating and are insoluble in water. They dissolve or swell in organic solvents and are capable of forming films. The major components of natural resins are resin acids, monohydroxy and polyhydroxy alcohols (resinols), esters of resin acids and resin alcohols or monohydroxy phenols (tannols), and chemically inert compounds, which are apparently heterocyclic compounds. Essential oils and water may also be present; the exact chemical composition of most natural resins has not been established.

Natural resins with the greatest commercial importance include rosin, copal, shellac, amber, mastic, sandarac, dammar, and acaroid resin. Until the 1930’s, natural resins were widely used in the production of oil varnishes (copal, amber), spirit varnishes (shellac, “soft” copals, sandarac), and resin varnishes (dammar, mastic), as well as in the production of adhesives, phonograph records, linoleum, embalming agents, sealing wax, and compositions for fumigating candles. The sharp drop in demand for natural resins in recent years has been caused by the introduction of synthetic products. In the modern paint and varnish industry, rosin and the products of its modification, shellac, and amber (wastes from the production of ornaments) are the most frequently used natural resins. Natural resins are also used in the production of soaps, luminophors, polishes, sizes, cosmetic preparations, plasters, and chewing gum.

M. M. GOL’DBERG

natural resin

A solid, thermoplastic organic substance which occurs in nature; is flammable and a nonconductor of electricity.
References in periodicals archive ?
Isoprimaric acid (1), mercusic acid (2), neoabietic acid (3), and dehydroabietic acid (4) are natural resin acids.
This high purity results in superior natural resin whiteness and improved thermal stability.
Benkreira and Britton's mixing experiments indicated that the viscosity ratio at the processing conditions of the natural resin to that of the masterbatch resin should be as high as possible.
Molders that have thermal-gate hot runners will benefit from pulling the bubbles and establishing natural resin in the gate area.
The hoppers bins are typically used for natural resin, regrind, color, and additives.
The Biotube is made from a material derived from flax, which the company hopes to source from North Wales farmers, and a natural resin extracted from a plant grown in Brazil.
The natural resin cells of the wood also tend to interfere with the gluing process.
As a simple check, run natural resin with no color and note whether recovery time decreases.
The Maguire WSB 260R4 has six hopper bins: two large ones for natural resin and regrind and four minor-ingredient bins that are removable for fast color and additive changes and easy cleanout.
Another symptom of this poor level of homogeneity is color swirls in parts where mixtures of natural resin and color concentrate are used.
To test this, five colors were prepared as precolored in a UV acetal copolymer resin and also molded at the press in 20:1 concentrates using UV acetal copolymer natural resin.
While the cost per pound for color concentrates can be very high, these materials are typically only added at letdown ratios of 2 to 5 lb per 100 lb of natural resin.

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