Exporting PC Compounds to the USA: What UL Certification Actually Means

What the yellow card really is

UL recognition for plastics is recorded on a Yellow Card. Each card covers one grade from one manufacturer and lists its flammability rating at each thickness tier plus electrical parameters such as RTI, HWI and HAI.

When an equipment maker seeks UL listing for the finished product, they reference the plastics supplier's yellow card number. Without a matching card, the equipment listing stalls.

Beyond UL94 there is RTI

Many buyers focus solely on the UL94 flame class and overlook RTI, the Relative Temperature Index, which is split into electrical, mechanical impact and mechanical without-impact values. RTI governs service life at operating temperature.

A material with RTI Electrical of 80 °C is non-compliant in a part running continuously at 100 °C, even if it passes V-0.

Plan the schedule in advance

UL certification of a new grade typically takes 6-10 weeks, with cost depending on the number of thickness tiers and colours. Confirm the scope early: which thicknesses matter (commonly 3.0 / 2.0 / 1.6 / 0.8 mm), which colours, and whether full-colour (ALL) coverage is needed.

Full-colour coverage avoids re-testing every shade but requires the formulation to be tolerant across all pigments — harder for halogen-free FR systems.