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Why core spun threads should I use for denim?

In daily life, you can often see fashion items of denim fabrics. No matter whether denim clothes or jeans, they are enduring styles, and the characteristics and unique processing technology of denim fabrics have higher requirements for sewing threads, then What sewing thread should I use for denim sewing to be more assured?

What is denim?

First of all, we need to understand the characteristics of denim. Denim is a warp twill fabric. It is generally composed of cotton threads with high special numbers, that is, relatively thick, so it is relatively rough and wear-resistant, and has a long service life, and the characteristics of the fabric determine.

The sewing thread used for denim

The sewing thread used for denim needs high strength and wear resistance. Poor quality sewing thread often leads to sewing thread breakage of denim clothing after several pieces of washing, which affects the appearance and reduces the overall clothing texture, and effect the life of denim.

Special production process

The second thing to consider is the special production process of denim clothes. After the denim clothes are sewn, they generally need to go through the process of washing, and the denim clothes are polished with pumice or chemicals to achieve a certain fading effect and a sense of staleness. The ever-changing styles of denim clothing have high requirements on the washing performance of the sewing thread. After washing, the high-quality sewing thread can effectively prevent the stitches from fluffing or even being damaged and ensure the aesthetics and quality of the denim clothing. Wearing comfort.

Cotton-coated polyester core-spun sewing thread

Taking these two points into consideration, a cotton-coated polyester core-spun sewing thread is recommended. The surface of the core-spun sewing thread is soft natural cotton yarn, which can take into account the ductility and wearing comfort, and the inner is high-strength filament polyester, which has strong toughness Durability, and abrasion resistance, and washing characteristics are quite outstanding, it can be said to be an ideal material for sewing denim.


In addition to considering the strength of the sewing thread, uniformity is also very important. The routing of denim clothes often takes into account the role of decoration. Therefore, the sewing thread should also be smooth and uniform in thickness, so that the stitches of the sewing thread will be flat and beautiful. A detail often determines the texture of denim. High-end brand denim pays great attention to the beauty of the thread. Therefore, when choosing sewing threads, it is necessary to choose sewing threads with stable quality control, which can effectively avoid problems such as thick knots.

Read More: Thread for Sewing Machine

Core Spun Sewing Thread
Core Spun Sewing Thread

What are Corespun Threads?

Corespun threads sometimes referred “score” or “polycore” or “cotton core”, are made by wrapping a staple polyester or cotton wrapper around a continuous filament bundle of polyester fibers during spinning, and then plying these yarns into a sewing thread. The continuous filament polyester core makes up approximately 60% of the thread construction.

Pros of Core-spun Threads

  • Higher strength per size (higher tenacity)
  • Greater uniformity in size, strength, and other physical characteristics•
  • A higher initial modulus or resistance to stretching contributes to better loop formation and reduced seam puckering.
  • Better ply security – fewer unravel-type thread breaks
  • Superior abrasion resistance & durability

Core-spun Threads vs Filament Thread

The wrapper of a corespun thread can be either staple polyester or staple cotton. The wrapper gives the thread a fibrous surface that contributes to:

  • A softer “hand” or feel than a 100% continuous filament threads
  • A matte finish stitch appearance similar to a spun thread construction
  • Superior frictional characteristics compared to a continuous filament threads

Poly wrapper vs cotton wrapped

Poly wrapper

  • Superior color fastness, chemical and abrasion resistance
  • Higher strength than cotton wrapped corespun threads
  • Superior “union dyeing” because of one-step dyeing process

Cotton wrapper

  • Superior needle heat resistance
  • A “wash-down” stitch appearance

Top 5 benefits of using core spun yarns on denim?

  • Benefit 1: 40 to 50% stronger than spun polyester threads the same size
  • Benefit 2: Superior sewability on both manual and automatic machines with minimum interruptions – fewer restitched seams.
  • Benefit 3: Helps to Minimize Open-Seams and Seam Failure
  • Benefit 4: Allows the use of smaller diameter thread to minimize Seam Puckering or Needle cutting
  • Benefit 5: Helps to minimize broken and cut stitches after finishing.

Read More: Filament Sewing Thread