There are two types of core spun sewing thread. They are cotton wrapped poly core, (D-Core) and the poly wrapped poly core, (Perma Core).
Perma Core is a premium poly wrapped poly core spun product that delivers a higher seam strength and sewing performance over spun products, allowing for smaller thread sizes. This helps minimize seam puckering and needle cutting. Perma Core is produced by spinning polyester around a high tenacity continuous-filament core to form a single yarn. Then these yarns are twisted together to make one thread. Because Perma Core is 100% polyester, it offers good chemical and abrasion resistance and superior colorfastness in the finished seam. It is available in a full range of colors and sizes.
D-Core is premium cotton wrapped poly core product that is produced like Perma Core except the high tenacity yarn is wrapped with cotton staple instead of polyester. Because of the cotton wrap, it offers better needle heat resistance than Perma Core and provides a “washed down” look during garment-washing processing, giving a soft, low-sheen appearance. Because of the high tenacity continuous-filament core, D-Core also offers a high seam strength which allows for small thread sizes. D-Core is also available in a full range of colors and sizes.