Decide the test conditions before you approve the sample
When a PVC label is going onto a garment that will be washed, chlorine-bleached, or worn against skin in a humid climate, the question is not whether to run a pvc label color fastness test but which conditions to specify. Get the conditions wrong and a passing lab report tells you nothing about what happens in a customer's washing machine. This article covers the conditions worth writing into your purchase order, the standards behind them, and how to read results.
PVC labels behave differently from woven or printed fabric labels. The material is a plasticised film, so colour sits in or on a polymer rather than in dyed yarn. That changes which test methods are relevant and which failure modes you should expect.
What a pvc label color fastness test actually measures
Colour fastness testing checks how much colour leaves the label and how much it changes under a defined stress. For PVC labels the usual stresses are:
- Rubbing (crocking) — dry and wet rub with a standard white cloth, assessed against a grey scale.
- Water and perspiration — immersion and contact with artificial alkaline and acidic sweat, then assessment of both colour change and staining of adjacent fabric.
- Laundering — a defined wash cycle at a set temperature, followed by colour change and staining assessment.
- Light — exposure to controlled light, relevant for outdoor and display-facing labels.
- Plasticiser migration — specific to PVC: plasticiser can carry pigment to the surface or into neighbouring materials over time.
Each of these produces a number on a 1–5 grey scale, where 5 means no change. Most apparel programmes set a minimum of 4 for colour change and 3–4 for staining, but the right threshold depends on the end use.
Conditions to write into your spec
The conditions matter more than the method name. A crocking test run dry tells you little about a label that will sit under a sweaty strap. Specify the following in your tech pack or purchase order.
Wash conditions
State the temperature, cycle and number of washes. A common specification for apparel trims is 40°C, one wash cycle, assessed after drying, with a note on whether tumble drying is included. If the garment is sold as machine-washable at 60°C, test at 60°C — testing at 40°C and shipping a 60°C care claim is a mismatch your customer will find.
Perspiration and water
Ask for both alkaline and acidic artificial perspiration, since skin chemistry varies. For water, specify immersion time and whether the assessment covers staining of a standard adjacent multifibre fabric.
