Synthesis of rosin-based resins and their application in waterborne coatings

Rosin is a common natural product consisting of a mixture of tricyclic diterpene resin acids with a hydrogenated phenanthrene structure, which is widely used in coatings, inks, adhesives, paper, soaps, food and pharmaceutical industries
.

Rosin can be modified
by the addition of double bonds in the rosin skeleton structure, hydrogenation reaction, esterification and ammonolysis on carboxyl groups.
If rosin-based polyols are prepared first, and then react with polyisocyanates, the characteristic structure of rosin can be introduced into polyurethane to improve the physical and chemical properties of polyurethane coatings coatingol.
com
.

At present, the types of modified products of rosin to polyurethane are mainly solvent-based, waterborne, solvent-free and non-isocyanate rosin-based polyurethanes
.

Waterborne polyurethane uses water as solvent, has the advantages of no pollution, excellent mechanical properties, good substrate adaptability, easy modification, etc.
, and is widely used in automobile processing, industrial metal coating, wood coating and plastic coating.

Compared with solvent-based rosin-based polyurethane, waterborne rosin-based polyurethane not only combines the natural renewable, biodegradable and biocompatible characteristics of rosin and the environmentally friendly advantages of waterborne polyurethane, but also the introduction of rosin can make up for the defects of poor mechanical properties, long curing time and poor water resistance of waterborne polyurethane, and has great development potential
as a new degradable environmentally friendly material.

Rosin-modified waterborne resins have better gloss and heat resistance, and are easy to form films, and are widely used
in waterborne coatings.
Polyurethane/rosin composite coatings have better anti-fouling properties
.

The addition of rosin significantly increases the long-term release rate of the antifouling agent and imparts the self-polishing properties
of the coating in seawater.
Both rosin and PCL are biodegradable, avoiding pollution of the marine environment by
coatings.