What does Polycore Denim mean?
A type of denim that combines polyester and cotton to create a garment with a mix of strength and authentic feeling.
Heddels explains Polycore Denim
Manufacturers often use polycore, or core spun, thread for the stitching on the hems and seams on jeans. This thread contains a polyester core wrapped in a thin layer of cotton or another layer of polyester. This process produces a stronger and more durable thread than one made of entirely natural products and is especially resilient to harsh finishing procedures such as stone or river washing. In addition, polycore thread helps control shrinkage and minimizes wrinkles.
Here are some various colors of polycore thread: