Formaldehyde-modified gum rosin is a type of rosin that has been chemically modified through a reaction with formaldehyde. Rosin, also known as colophony, is a natural resin derived from pine trees and is commonly used in various industrial applications.

The modification process typically involves heating gum rosin with formaldehyde under specific conditions, resulting in the formation of a modified resin. This modification alters the properties of the rosin, making it more soluble in certain solvents and improving its compatibility with other materials.

Formaldehyde-modified gum rosin finds applications in industries such as adhesives, coatings, inks, and rubber compounding. It is often used as a tackifier or as a component in adhesive formulations to enhance adhesion and cohesion properties.

However, it's important to note that formaldehyde is a known irritant and potential carcinogen, so proper safety measures should be taken during the handling and processing of formaldehyde-modified rosin products.