Why socks need nylon: the three per cent that hold the shape
Nylon gets blamed for being «synthetic». Yet a woollen sock without it loses its shape within a month, and a cotton one rubs through at the heel within a season. Here is how much is needed, and what it actually does.
You read the label: merino wool 70%, polyamide 28%, elastane 2%. The hand wants to put the sock back on the shelf — «too much synthetic». And yet those twenty-eight per cent are exactly what makes the pair look the same in six months as it did on the day you bought it.
What nylon actually does
Wool does not hold its shape on its own: it stretches where the heel presses and thins where the shoe rubs. Nylon takes that load. In a sock it has three working places: the heel, the toe and the cuff rib. The first two it protects from abrasion, the third it keeps from stretching into a loose ring.
Polyamide fibres are several times stronger in tension than wool fibres. That is why 25–30% nylon roughly doubles the life of a pair — at the same weight and the same thickness of fabric.
How much is needed
Up to 15% — pleasant in the hand, short-lived on the foot: these are the pairs that rub through at the heel within a season.
20–30% — the working range for everyday woollen socks. Wool still feels like wool, and the shape holds.
35–40% — sports and work models, where wear matters more than touch.
Above 45% — you are buying a synthetic sock with some wool added, not the other way round.
When there is too much
If the label says 20% wool and 60% polyamide, the word «wool» on the price tag is marketing rather than content. Such a sock is warmer than cotton, but not warmer than wool — and it costs like wool.
The rule is simple: wool is responsible for warmth and feel, nylon for how long the pair lasts. What matters is not whether it is present, but in what proportion.