Ester gum

Description

A modified resin natural resin made from rosin that has been esterified by heating with a polyhydric alcohol, such as glycerol. Ester gum contains the glyceryl, methyl, and ethyl esters of rosin acids. Ester gums are lighter in color than rosin and have a higher softening point but lower acid number. They are used instead of copal, dammar, or resin kauri in making organic enamels, paints, nitrate nitrocellulose lacquers, and oil tung oil mixtures. Ester gums are not used in artist paints or varnishes although they have been tried for wax-resin linings.

Synonyms and Related Terms

gum rosin; colofonia esterificada (Esp.); wood rosin; rosin ester

Other Properties

Soluble in amyl acetate, turpentine carbon tetrachloride. Insoluble in water.

Hazards and Safety

Combustible.

Authority

• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 3745

• G.S.Brady, G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 672

• Richard S. Lewis, Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• R. J. Gettens, G.L. Stout, R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966

• Ralph Mayer, Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

• ASTM, ASTM, "Standard Terminology Relating to Paint, Varnish, Lacquer and Related Products", Annual Book of ASTM Standards, Section 6, Paints, Related Coatings and Aromatics, ASTM, D16, 7-Jan, Jul-96

• Guy Weismantel, Guy Weismantel, Paint Handbook, McGraw-Hill Book Company, New York, 1981