Core Spun Yarn
What does Core Spun Yarn mean?
A yarn in which a base yarn is completely wrapped by a second yarn.
Heddels explains Core Spun Yarn
Core spun, or “polycore”, yarn is created by twisting staple fibers around a central filament core, usually made of polyester for extra strength.
It is 40% to 50% stronger than normally spun yarn of the same weight, and reduces the number of broken stitches when sewing seams and hems on denim.
Additional Resources
Diagram of core spun yarn:
Source: stphilsaleveltextilesdept.blogspot.com
Breakage of Core Spun Yarn v.s. Spun Poly Yarn:
Source: denimsandjeans.com