HEMA: Properties, Applications and a Buyer Guide
What makes HEMA different from HEA, where it is used, and the documents a buyer should request before ordering.
Hydroxyethyl Methacrylate (HEMA), CAS 868-77-9, is the methacrylate counterpart of HEA. Structurally the two are close, but the difference in the alpha-methyl group changes the polymerisation behaviour, and that difference is what makes HEMA a distinct choice rather than an alternative name.
The difference from HEA
Both monomers carry a hydroxyl group and a polymerisable double bond. In HEMA, the double bond is methacrylate: a methyl group sits on the carbon adjacent to the carbonyl. This changes two practical characteristics. The resulting polymer is more resistant to hydrolysis and generally more thermally stable. It also tends to cure to a harder, more durable film.
The trade-off is straightforward: methacrylates generally cure more slowly than acrylates. For a high-throughput UV line, that can matter. For a line curing at lower intensity or needing extended pot life, it may not.
Where HEMA is used
HEMA appears in UV-curable coatings, acrylic and methacrylate resins, automotive and industrial coatings, printing inks, adhesives and sealants, and in specialty polymer work where a methacrylate backbone is preferred.
Its hydroxyl group performs the same role as in HEA: it stays available for crosslinking with isocyanate or melamine systems, which is what allows a coating to be built as a two-component or self-crosslinking system.
Documents to request before ordering
Technical data sheet for your grade. HEMA is produced in more than one purity grade. The TDS is the document that states which one you are buying and what it contains.
Safety data sheet. Required for handling, transport and import documentation in almost every destination market.
Sample certificate of analysis. Useful as a reference point for typical values when you are qualifying a new grade or a new supplier.
REACH documentation. Available for HEMA; the file is listed on the product page and can be opened directly.
A note on storage
HEMA is supplied in 200 kg HDPE drums, with ISO tanks and bulk containers available for larger movements. Store in a cool, ventilated place, keep the container tightly closed and protect from heat and sunlight.
