Spandex Covered Yarn (SCY) and Core-Spun Yarn in Knit Fabrics
Whether elastane is bare, single-covered or double-covered changes recovery, hand feel and the risk of grin-through on the finished fabric.
This guide explains the underlying principle, the numbers that matter and the checks that keep results consistent.
Bare, single-covered and double-covered
Bare elastane is cheap but fragile; single covering protects it with one filament wrap, double covering adds a second wrap for harsh processing.
Buyers who set expectations at the development stage spend far less time resolving complaints after the season has started.
Why covering matters for recovery
A covered yarn holds the elastane under controlled draft, so the knitted loop returns to shape more consistently after stretching.
Where a standard exists, name the standard number, since a value without a method cannot be verified by a third party.
- Agree tolerances in writing before the first sample is made
- Define the measurement condition and the direction measured
- Review the limit each season against real performance data
Grin-through and appearance
Insufficient covering, or too low a twist, allows the elastic core to grin through the fabric surface on light colours.
Train operators on what the parameter looks like when it is wrong, since most defects are visible long before testing.
Specification values
State the elastane denier, draft ratio, cover yarn denier and the twist per metre on the yarn ticket.
Keep reports on file with the sample identification, so results can be traced back to a specific roll or batch.
- Record settings and raw material lots for every approved production run
- Check in-process rather than relying on final inspection
- Escalate deviations the same day they appear
Cost versus performance balance
Double covering costs more but reduces returns on high-stretch products, so match the covering to the garment end use.
Choose suppliers who understand the requirement, because competence reduces the hidden cost of rework.
Summary
Buyers who verify rather than assume obtain better fabric at the same price, and fewer surprises after the goods arrive.
