Combining glycerine (a byproduct from processing vegetable or animal fats) with an organic polyacid like citric acid can make bio-derived polyesters.

Combining glycerine (a byproduct from processing vegetable or animal fats) with an organic polyacid like citric acid can make bio-derived polyesters. This basic chemistry, known for a century, is used to make varnish and coatings. But according to a recent patent application, Procter and Gamble Co., Cincinnati, can combine the raw ingredients in pellet form and then reactively compound them in a conventional mixing extruder. The mixture is described (U.S. Pat. Applic. 20080200591, Aug. 21, 2008) as a combination of a polyhydric alcohol (glycerol or glycol); an organic acid (adipic, citric, maleic, succinic, polyacrylic or some combination); and an anhydride (succinic, maleic, phthalic or some combination) together with any of a number of common fillers like talc or clay. The technology was invented by Dr. Isao Noda, who previously developed P&G’s Nodax PHA biopolymer. The invention targets using glycerol, a plentiful byproduct from production of bio-diesel from animal and vegetable oils, to make a melt-processable plastic for molding, sheet, film, fiber or foam. (513) 983-1100 • www.pg.com