... sylvic acid), a resin acid, is the primary irritant in pine wood and resin, isolat Abietic acid (also known as abietinic acid or ... acid, is the primary irritant in pine wood and resin, isolated from rosin (via isomerization) and is the most abundant of several closely ... the rosin acids, which are otherwise soft, tacky, and low-melting and subject to rapid deterioration by oxidation in air. Stability ...