Polyurethane vs Epoxy Dome Labels: Which Resin is Better?

Understanding the Two Main Dome Resins

When it comes to dome labels, the resin used to create the raised 3D dome is the most critical material choice. The two primary options are polyurethane (PU) resin and epoxy resin. Both create a glossy, transparent dome over a printed label, but their chemical compositions lead to very different performance characteristics over time.

Understanding the differences between polyurethane and epoxy is essential for choosing dome labels that will look great and perform reliably for years. In this guide, we break down every important factor so you can make an informed decision.

Polyurethane Resin: Properties & Advantages

Polyurethane (PU) resin is the industry-standard material for premium dome labels. It is a two-part compound that cures into a flexible, crystal-clear dome with excellent optical properties. Here are its key characteristics:

• +Superior UV Resistance — PU resin contains built-in UV stabilizers that prevent yellowing and degradation from sunlight. Labels maintain their clarity for 5-7+ years outdoors.
• +Excellent Flexibility — Polyurethane remains flexible after curing, meaning it won't crack or chip when applied to curved surfaces or when exposed to temperature changes.
• +No Yellowing — Unlike epoxy, polyurethane resin does not yellow over time. The dome stays clear and colorless, preserving the integrity of the printed design beneath.
• +Chemical Resistance — PU domes resist common chemicals including cleaning agents, solvents, fuels, and oils without degrading or becoming cloudy.
• +Self-Healing Properties — Minor surface scratches on polyurethane can partially self-heal over time, maintaining the glossy appearance of the dome.

Epoxy Resin: Properties & Limitations

Epoxy resin was one of the earliest materials used for dome labels and is still available as a lower-cost alternative. While it can produce a clear dome initially, it has several well-known limitations:

• -Yellowing Over Time — The most significant drawback of epoxy is that it yellows when exposed to UV light. This discoloration can begin within months of outdoor exposure and worsens progressively.
• -Brittle When Cured — Epoxy cures to a very hard but rigid state. This makes it prone to cracking on curved surfaces and when subjected to impact or temperature fluctuations.
• -Poor UV Stability — Without UV stabilizers, epoxy breaks down under sunlight, leading to chalking, hazing, and loss of gloss in addition to yellowing.
• +Lower Cost — Epoxy resin is generally cheaper than polyurethane, which is why some budget-focused manufacturers still offer it.
• +Greater Hardness — Epoxy cures harder than PU, which provides slightly better scratch resistance in the short term. However, this hardness also contributes to brittleness.

Side-by-Side Comparison