Resin acid

In 2005, as an infestation of the Mountain pine beetle (Dendroctonus ponderosae) and blue stain fungus devastated the Lodgepole Pine forests of northern interior British Columbia, Canada, resin acid levels three to four times greater than normal were detected in infected trees, prior to death.

Increasing resin production has been proposed as a way to slow the spread of the beetle in the "Red Zone" or the wildlife urban interface.

In this form, the sodium salts are poorly insoluble and, being of lower density than the spent pulping process liquor, float to the surface of storage vessels during the process of concentration, as a somewhat gelatinous pasty fluid called kraft soap (also called resin soap).

Resin acids, because of the same protectant nature they provide in the trees where they originate, also impose toxic implications on the effluent treatment facilities in pulp manufacturing plants.

Furthermore, any residual resin acids that pass the treatment facilities add toxicity to the stream discharged to the receiving waters.

The chemical composition of tall oil varies with the species of trees used in pulping, and in turn with geographical location.

In general, the tall oil produced in coastal areas of the southeastern United States contains over 40% resin acids and sometimes as much as 50% or more.

Resin acids are converted into ester gum by reaction with controlled amounts of glycerol or other polyhydric alcohols.

Resin acids are very poorly soluble in water (milligrams per liter) and have low acute toxicity.