Fibers with a boiling water shrinkage rate of around 20% are referred to as regular shrinkage fibers, while fibers with a rate of 35-45% are called high shrinkage fibers.

Classification 

(1) Classified by composition, there are two types: high-shrinkage polyacrylonitrile fibers (PAN) and polyester fibers (PET). Our company can supply polymers for boiling water rate polyester fibers. For more information, please refer to https://www.polyestermfg.com/high-shrinkage-polyester-chip/.

(2) Classified by boiling water shrinkage rate, there are regular and high shrinkage ones.

Production 

(1) Chemical Modification Method

The copolymer components were added to the polymer molecules (polyester and acrylic fibers) to reduce the internal rotation activation energy of macromolecules, increase the high elastic shape variable during stretching, reduce the crystallization rate and crystallinity, and thus increase the shrinkage rate of fibers.

(2) Physical Modification Method

Modify the spinning, stretching, and post-processing processes of fiber formation, such as using low-temperature, low-draw ratio, and low-temperature drying tools to give the fiber proper orientation without crystallization or with minimal crystallization, thereby increasing the fiber’s shrinkage rate.

Applications 

High-shrinkage polyester fibers are generally blended with regular polyester fibers, wool, cotton, etc., or interwoven with polyester cotton and pure cotton yarns to produce fabrics with unique styles. It can also be used to manufacture artificial fur, synthetic suede, blankets, etc., exhibiting characteristics such as soft texture and dense pile. Typical products include:

Polyester faux fur fabrics: Using high-shrinkage polyester yarns interwoven with low-shrinkage and non-shrinkage fibers.

The fabric is treated with boiling water to induce varying degrees of curling, creating a fluffy texture. This method is commonly used in the production of polyester faux fur fabrics.

Bubble yarn and high-crepe fabrics: Intertwining high-shrinkage polyester yarns with low-shrinkage yarns, where high-shrinkage polyester yarns form the base or pattern grid and low-shrinkage yarns create the raised woven surface. After post-processing, these fabrics can be made into permanent bubble yarn or high-crepe fabrics.

Synthetic leather: High-shrinkage polyester with a boiling water shrinkage rate of over 50% is used to manufacture synthetic leather. It is often blended with regular polyester, wool, cotton, etc., or interwoven with polyester-cotton and pure cotton yarns to produce fabrics with a distinctive style.

Applications of High-Shrinkage Polyacrylonitrile Fibers

Products made from high-shrinkage polyacrylonitrile fibers exhibit a soft feel, fluffy texture, and good warmth. Previously, they were used to produce short fibers for artificial fur or were blended with regular polyacrylonitrile fibers for various applications. However, their current uses are extensive.

Blending high shrinkage with regular polyacrylonitrile fibers to create yarns. Subsequently, subjecting them to boiling or steam in a tension-free state causes the high-shrinkage material to curl. In contrast, the regular fibers curl into loops due to the constraints of the high-shrinkage ones. This results in fluffy, rounded yarns resembling wool yarns, producing polyacrylonitrile bulky yarn, knitted plush, and fancy yarn.

Note: The terms used here, such as bulky yarn, knitted plush, and fancy yarn, all fall under the category of bulky yarn, and the nomenclature, definition, and classification of bulky yarns are complex and varied, lacking standardization.

High shrinkage polyacrylonitrile fiber can be pure spinning, but also with wool, hemp, rabbit hair, and others blended into a variety of imitation cashmere, imitation hair, imitation mohair, imitation hemp, imitation silk, and other products.