How to Tell If Plastic Resin Is Virgin or Recycled

Worried your supplier sold you recycled resin instead of virgin? Learn practical checks — from TDS reading to material testing — to verify resin quality before it disrupts production.

Start With the TDS — But Don’t Stop There

Visual Inspection: Pellets Don’t Lie

The Smell Test (Yes, Really)

If the bag smells like a chemical fire or a landfill, walk away.

Density Test: The Float/Sink Check

• Different polymers behave differently in density testing: If a result is inconsistent with the specified resin, treat it as a reason for further laboratory identification rather than a final verdict.

• Impact strength: This property is especially important for safety-critical or high-stress parts. Significant deviation from the agreed grade’s TDS should trigger a material review.

Agree the acceptable gel or contamination level before purchase, especially for appearance-critical film, fiber, optical, or medical applications. The limit should be application-specific and documented in the purchase specification.

The apparent saving on resin can disappear quickly when a production run becomes unstable or finished parts have to be held for investigation. A documented approval process is usually less costly than discovering a mismatch after molding has started.

Frequently Asked Questions