Wash testing heat transfer labels: ISO 6330, ISO 105-C06 and AATCC 61
Brand buyers rarely accept "washes well" on a quotation. Before a heat transfer label goes into bulk, agree which wash procedure, how many cycles and which ratings will decide pass or fail — and keep the print-line settings that produced the samples.
Agree the test plan before printing samples
Ask the buyer for the exact method, procedure code, number of cycles, drying method and the garment fabric to be used. A label that passes on cotton jersey may behave differently on polyester knit, nylon or coated fabric.
Record the transfer construction with the request: carrier film, ink system, number of colours, adhesive layer and heat-press time, temperature and pressure. Without this, a passed report cannot be repeated in bulk.
Know what each standard measures
ISO 6330 defines domestic washing and drying procedures used to age textile specimens. It covers three reference machine types (front-loading and two top-loading designs) and six drying procedures, and warns that changing machine, detergent or dryer can change results.
ISO 105-C06 and AATCC TM61 assess colourfastness to laundering. In ISO 105-C06 a single (S) test approximates one wash and a multiple (M) test can match up to five washes at no more than 70 °C. AATCC TM61 Test 2A approximates the colour change of five home launderings in one 45-minute run, but cannot always predict staining.
Inspect the label, not only the colour
Colourfastness ratings describe colour change and staining. For a heat transfer label, also inspect edge lifting, cracking across stretch zones, loss of raised height on silicone or puff prints, and adhesion after the garment has rested.
Photograph the same labels before and after each agreed cycle count under the same light. Note where failures start — at fine text, at overlapping colours, or at the adhesive edge — because each points to a different production variable.
Connect results back to the screen printing line
Keep mesh count, stencil thickness, squeegee setting, ink and adhesive lot, dryer profile and web speed for every sample batch. When a bulk lot is later questioned, these records show whether the line ran the approved settings.
Retain approved reference labels from each lot. Repeat the agreed wash test when the film, ink, adhesive or fabric changes, instead of relying on an older report.
Related process and equipment
- Write the method, procedure, cycles and drying method on the sample request.
- Test on the actual garment fabric and heat-press settings.
- Inspect edges, stretch zones and raised areas, not only colour.
- Store line settings and retained labels for each approved lot.
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Frequently asked questions
Does passing AATCC 61 Test 2A prove a label survives five washes?
It approximates the colour change of five home launderings. The method notes that staining is not always predicted, and it is not a dedicated adhesion test, so inspect lifting and cracking separately.
Is ISO 105-C06 suitable for industrial workwear laundering?
Its scope is domestic and commercial laundering of normal household articles. Industrial and hospital laundering can be harsher, so agree a separate procedure with the workwear buyer.