2-Hydroxyethyl methacrylate
The functional monomer that puts hydroxyl groups on acrylic resins, turning them into polyols that crosslink with isocyanates.
2-Hydroxyethyl methacrylate is a methacrylate ester carrying a primary hydroxyl group (molecular weight about 130.1 g/mol). It is a clear liquid miscible with water and many solvents.
HEMA is copolymerized into acrylic polyols for 2K polyurethane topcoats and clearcoats, and into some latex and UV-cure resins to add adhesion and crosslinking sites. The amount used sets the polyol’s hydroxyl content and crosslink density.
Its methacrylate double bond polymerizes into the acrylic backbone, leaving the –OH group pendant. Those hydroxyls react with isocyanate hardeners to form urethane crosslinks, or with melamine resins in baked finishes.
HEMA is a well-documented skin sensitizer and allergic contact dermatitis is common with uncured (meth)acrylates. Avoid all skin contact and use suitable gloves, since some glove materials are quickly permeated by acrylates.
It supplies the hydroxyl groups on acrylic polyols that react with HDI or IPDI hardeners, forming the crosslinked network of a 2K acrylic urethane.
The concern is mainly uncured monomer. Fully cured polymers contain very little free monomer, but raw material handling requires strict skin protection.
