Can we use printed heat-transfer labels instead of sewn labels inside our underwear, and what must they show?
Printed labels are allowed if they carry the required information, stay legible for the life of the product and survive washing. Test them washed and check comfort on the skin side.
Customers complain about scratchy sewn labels in our briefs. We want to print the size and care information with heat-transfer labels. The factory says it is common. What must we check?
Main answer
Printed or heat-transfer labels are widely used inside underwear and activewear to avoid scratchy tags. The legal requirements do not stop at the label’s material: the same information must be present, readable and durable. The decision is therefore about whether the print meets those requirements and the wearer’s comfort.
What must be on the product
Under the FTC Textile Rules, 16 CFR Part 303, a label with the required information, which includes fibre content, the manufacturer or RN identity and country of origin, must be affixed in a secure manner and be durable enough to remain attached throughout distribution, sale and resale until delivered to the consumer. For a product without a neck, such as briefs, the required information must appear on a conspicuous and readily accessible label inside or outside the product. The country of origin must be on the front side of its label.
Care instructions
The FTC Care Labeling Rule, 16 CFR Part 423, defines a care label as a permanent label or tag with care instructions that is attached or affixed so it will not separate and will remain legible during the useful life of the product. A heat-transfer print can serve as the care label only if it stays legible for that life. This is a test question, not an assumption.
Test the print
Wash finished garments with a procedure such as ISO 6330 for the number of cycles you consider the useful life, including the hottest drying step you allow. Check that every line of text is still legible, that no edges peel or crack, and that ink has not transferred to other garments. A rub test such as ISO 105-X12 for colour fastness to rubbing can indicate whether ink comes off by friction.
Comfort and construction
Print on a flat, stable area, away from seams and elastic where stretch will crack it. Check the edge of the transfer against the skin, because a stiff film can feel as rough as a tag. Heat transfer on elastane fabric needs correct temperature and time, so ask the factory for its settings and a sample washed repeatedly.
What to write
State label position, size, wording, language and number of wash cycles it must survive. Keep a washed approved sample.
Sources and further reading
- eCFR — 16 CFR Part 303, Textile Fiber Products Identification Act rules
- eCFR — 16 CFR Part 423, Care Labeling of Textile Wearing Apparel
- ISO 6330:2021 — Domestic washing and drying procedures for textile testing
- ISO 105-X12:2016 — Colour fastness to rubbing
Standards and rules are summarised from their published scope or official guidance. Use the current edition and confirm requirements for your market.
Three perspectives on this question
Purchasing perspective
I'd get the factory's transfer film specification and settings in writing, and ask for washed samples before agreeing to drop the sewn label.
Merchandising perspective
A tagless feel is a real comfort selling point, but a care label that has washed off is a legal and a service problem.
QC perspective
We'd wash finished briefs for the target cycles and check every line of printed text for legibility, edge lift and ink transfer.
Working on a similar program?Send your tech pack, fabric references and test requirements. We reply with a quote and the questions we need answered.
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