The difference between polyester filament yarn and polyester staple fiber

There are many differences between polyester filament yarn and polyester staple fiber in terms of their process flow and post-application.

I. Process Flow

1. Raw Materials and Preparation

Polyester Filament Yarn: Mainly uses purified terephthalic acid (PTA) and ethylene glycol (MEG) as raw materials. Through esterification or transesterification and polycondensation reactions, polyester melt is produced, which then undergoes spinning, drawing and texturing processes to form the final product. According to different production methods, it can be divided into direct melt spinning and chip spinning. In direct melt spinning, the melt is directly fed into the spinning machine; in chip spinning, polyester chips are first produced, then dried, melted, and finally spun.

Polyester Staple Fiber: After producing polyester melt from PTA and MEG, two processes can be adopted: direct melt spinning and batch spinning. Direct melt spinning omits the chip-making process, enabling direct spinning and cutting to produce staple fibers. Batch spinning, however, requires first producing polyester chips, followed by drying, melt spinning, and cutting steps.

2. Spinning, Drawing and Texturing

Polyester Filament Yarn: Spinning processes are classified by spinning speed into conventional spinning, medium-speed spinning, and high-speed spinning. Common process routes include the POY-DTY process and FDY process. Among them, the POY-DTY process is the most widely used for producing textured yarns. It adopts high-speed spinning and high-speed drawing-texturing. POY (Partially Oriented Yarn) has a certain degree of orientation and a relatively stable structure, allowing long-term storage and long-distance transportation. The DTY (Draw Textured Yarn) produced from it has excellent quality.

Polyester Staple Fiber: After spinning, the fibers need to go through drawing, crimping, and heat-setting processes. During drawing, the molecular chains of the fibers are further oriented and crystallized, thereby improving the fiber's physical properties such as strength and modulus. The crimping process gives the fibers a wool-like crimped shape, which helps enhance the warmth retention and bulkiness of the fabric, and also facilitates better interlacing and holding of the fibers in subsequent spinning processes.

3. Cutting and Post-treatment

Polyester Filament Yarn: Generally, no cutting is required. It is directly wound into bobbins of a certain shape for subsequent processing such as weaving. However, for some special applications (e.g., making sewing threads), it will be cut into a specific length as needed.

Polyester Staple Fiber: After spinning and drawing, the fibers go through a cutting process, where they are cut into short fibers of several tens of millimeters. Then, through post-treatment processes such as packaging, staple fiber products that are easy to transport and use are made.

II. Post-application

1. Textile Processing Methods

Polyester Filament Yarn: Usually, no spinning is needed; it can be directly used for weaving. It has high production efficiency and is suitable for large-scale, continuous textile production. During weaving, the strength and smoothness of filament yarn enable it to withstand large tension and friction, which is beneficial for improving weaving speed and efficiency. It is often used to produce various silk-like, silk-imitated fabrics, and industrial fabrics.

Polyester Staple Fiber: It needs to be spun into yarn before being used for weaving. Its spinning process is similar to that of natural fibers. It can be blended with other fibers (e.g., cotton, viscose fiber, linen, wool) according to different application needs and requirements to produce yarns with different properties and styles. It is widely used in the cotton spinning industry to produce various garment fabrics and home textile fabrics.

2. Product Characteristics and Applications

Polyester Filament Yarn: It has the characteristics of high strength, good heat resistance, and good wear resistance. Its fabrics have good drapability and a full, delicate hand feel. It is suitable for making various silk-imitated and wool-imitated garment fabrics (e.g., suit and shirt fabrics), and can also be used to weave decorative fabrics such as sofa fabrics, curtains, and automotive interior decorative fabrics.

Polyester Staple Fiber: It has an appearance similar to cotton, with good elasticity, warmth retention, and bulkiness. The woven fabric is comfortable, soft, and has good air permeability. It is mainly used to make garments such as shirts, T-shirts, and underwear. It can also be used to produce non-woven fabrics: spunlace non-wovens for wet wipes and medical purposes, and geotextiles, leather base fabrics, and linoleum base fabrics for engineering fields.