Name: Glycidyl Methacrylate (GMA)
Brand: Coatingsink
SKU: glycidyl-methacrylate-gma
Availability: InStock

Question 1

What makes GMA a key crosslinker in thermosetting powder coatings?

Accepted Answer

GMA-functional acrylic powder coatings cure via reaction of the epoxide group with solid diacid hardeners, most commonly dodecanedioic acid (DDDA). The GMA-acrylic resin is synthesized by free-radical copolymerization of GMA with methyl methacrylate, butyl acrylate, and styrene at 8–15% GMA content by weight. Upon melting and mixing in the extruder, the epoxide ring-opens with the carboxyl group of DDDA at stoichiometry, yielding a hydroxy-ester crosslink. This chemistry delivers excellent UV durability and low yellowing vs. TGIC, making it the preferred cure system for outdoor architectural and automotive exterior powder coatings under AAMA 2605 and Qualicoat Class 2 specifications.

Question 2

How is GMA used in UV-curable coating formulations?

Accepted Answer

In UV coatings, GMA functions as a reactive diluent and adhesion promoter. Its methacrylate group copolymerizes into the UV network during radical cure, while the pendant epoxide group remains intact and subsequently reacts thermally or with ambient amine to provide secondary crosslinking. This dual-cure mechanism improves chemical resistance and adhesion to metal and glass substrates, and is widely used in automotive OEM clear coats, electronics lacquers, and optical fiber coatings where conventional UV-only cure cannot guarantee sufficient through-cure on complex geometries.

Question 3

What storage and handling precautions apply to GMA?

Accepted Answer

GMA is inhibited with ~50–100 ppm MEHQ to prevent premature polymerization. Store in sealed containers at 5–25°C, away from heat, UV light, and oxidizing agents. Shelf life is 6 months under proper conditions; heat or UV exposure depletes the inhibitor and may trigger exothermic polymerization. Flash point is 76°C (closed cup); handle with nitrile gloves and goggles as the epoxide group is a mild skin sensitizer with repeated exposure. Keep away from peroxides and strong acids.

Purity	≥99.5%
Appearance	colorless transparent liquid
Molecular Weight	142.15 g/mol
Boiling Point	189°C (760 mmHg)
Flash Point	76°C (closed cup)
Density	1.073 g/cm³ (25°C)
Viscosity (25°C)	2–3 mPa·s
Refractive Index	1.449
Inhibitor (MEHQ)	50–100 ppm

Glycidyl Methacrylate (GMA)

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