What is polyester fiber?
The group of polyester fibers is the biggest group of fibers made by humans in the world. This group includes many different types of polymers, with polyethylene terephthalate (PET) being the most prevalent. Polyesters are made by polycondensing carboxylic acid derivatives and alcohols to make ester groups, as the name suggests. Polyester fibers are cheap, easy to work with, and have many useful qualities. The process conditions during fiber production can affect a wide range of mechanical fiber qualities, such as thermal and dimensional stability, strength, bulkiness, and fineness. The melt spinning technique is the principal way that fibers are made.
Polyester fiber (PSF) is a synthetic fiber composed entirely of polyester, derived from recycled PET bottle flakes. PSF crafted from PET chips is termed “Virgin PSF,” while PSF manufactured from recycled PET flakes is referred to as “Recycled PSF.” This versatile material finds extensive applications across the textile, automotive, and furniture sectors.
Polyesters are made by polymerization, or more specifically polycondensation, of dicarboxylic acids and aliphatic dihydroxy chemicals. To make polyethylene terephthalate (PET), which is made in vast amounts, terephthalic acid and ethylene glycol are used. To achieve a chain structure in a certain range of molecular weights, the water that comes from the reaction needs to be eliminated. In the next step, a melt spinning technique is used to make fibers. Spinnerets make filaments from the polyester melt. In further phases, these filaments are oriented, crystallized, and cut.
Polyester fiber or polyester staple fiber (PSF) has extensive applications in spinning, weaving, and non-woven processes, predominantly employed for filling pillows and sofas with fibers. Polyester fiber or polyester staple fiber comes in varying degrees of luster, categorized as semi-dull or bright. Additionally, through the integration of color masterbatch, polyester fiber or polyester staple fiber can be dyed to achieve optical white, black, and various other colors. Renowned for its lightweight nature, polyester fiber (or polyester staple fiber) is wrinkle-resistant and exhibits durability against light exposure and weather conditions, demonstrating resilience even in harsh climates.
- PET Fiber
Polyethylene terephthalate (PET) is the main polyester used in fiber production. The table below summarizes the physical parameters of PET, a semi-crystalline polymer. PET fiber is the most produced synthetic fiber in the world. PET fiber has high strength, good elasticity, excellent heat-setting performance, good heat resistance, acid and alkali resistance, and other properties.
| Crystal habit | Triclinic: one polymer chain per unit cell |
| Cell parameters | a = 0.444 nm, b = 0.591 nm, c = 1.067 nm, α = 100 degrees, β = 117 degrees, γ = 112 degrees |
| Cell density | 1.52 g/cm³ |
| Tm (DSC) | 260°C ~ 265°C |
| ΔHf | 140 J/g; 33.5 cal/g |
| Tg (solid chip) | 79°C (DSC) |
| Tg (drawn fiber) | 120°C (dynamic loss) |
| Specific gravity | 1.33 (amorphous, undrawn) and 1.39 (crystalline drawn fiber) |
- Other Polyester Fibers
Other polyester fibers include polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), poly-1,4-cyclohexanedimethyl terephthalate, polyethylene 2,6-naphthalate fibers, and various modified polyester-based fibers. Among them, PBT fiber has excellent resilience, mildew and moth resistance, good curling elasticity, antistatic property and dyeing properties. The PTT fiber has excellent dimensional stability, stain resistance, wrinkle resistance, abrasion resistance, and easy dyeing.
Structure
- Chemical Structure
Polyester fibers are synthetic fibers composed of polyester linear macromolecules produced by polycondensation of diols and dibasic acids or ω-hydroxy acids. The chemical structure of polyester fibers involves two aspects: one is the molecular level (molecular chain and its structure), and the other is the supramolecular level (crystalline and amorphous regions).
PET fibers have rigid benzene rings in their backbone. A single chain contains the sequence of six aliphatic groups (-CO-O-CH₂-CH₂-O-CO-). The practical coplanar arrangement of benzene rings, carboxyl groups and aliphatic molecular groups in adjacent chains allows for side-by-side alignment. The molecular chain structure of PET is shown in the figure. Therefore, the PET macromolecular chain shows great rigidity, which makes the PET fiber show some inherent characteristics, such as a higher melting point, higher rigidity and higher strength of the fiber.
Chemical structure of PET
Polyester fibers can be thought of as being composed of crystalline, oriented amorphous (mesophase binding molecules), and non-crystalline (amorphous) domains. Three-phase structural models of polyester and polyamide fibers are proposed, as in the figure below. The model includes microfibrils containing alternating amorphous and crystalline regions; these are interconnected by amorphous fibril phases formed primarily of linking molecules. Each phase is characterized by its volume fraction and orientation. [2]
Structural model of semicrystalline fibers [2]
- Fiber Structure
The fiber structure is highly dependent on the process parameters of fiber formation, such as spinning speed, drawing, and heat-setting. The final fiber structure is highly dependent on temperature, draw rate, draw ratio, relaxation and heat-setting conditions. The way the fibers are arranged and how much of them is crystalline can be changed a lot based on these process factors.
Polyester fiber is used for industrial products
Our range of industrial offerings caters to diverse applications, each featuring distinct specifications tailored to various markets, including automotive, appliance, industrial manufacturing, and packaging materials. This dynamic end market, subject to constant evolution, encompasses a wide array of products such as upholstery, paneling, hood linings, trunk liners, molded trim, and more.
Utilizing fabric crafted from recycled polyester staple fiber is prevalent in nearly all automobiles across the globe, owing to its cost efficiency and durability. This choice not only contributes to cost reduction passed on to customers but also enhances the overall feel and finish of the vehicle.
Polyester fiber is used for home textiles & bedding.
Our polyester fiber products are used in mattresses, quilts and non-wovens. Our customers are bedding suppliers and mattress fabricators, which are recognized names in the bedding industry.
Our range of polyester fiber products offers various lines of craft items, including fiberfill, pillows, decorative pillows, pillow inserts, toys, and other materials commonly used by home craft enthusiasts. These products are suitable for use by both hand and machine quilters.
Recycled solid polyester fiber is a key material employed in filling a wide array of products, including soft toys, cushions, sofas, and various furniture pieces. Opting for recycled polyester fiber offers cost-efficiency and contributes positively to the environment.
Advantages of polyester fibers:
- 1. Polyester fibers have high strength and elasticity, so they are durable, wrinkle resistant, need not be ironed, and have excellent light resistance. In addition, polyester fiber has excellent resistance to various chemicals. Acids and alkalis have little damage to it, and it is not afraid of mildew or moth damage.
- Polyester has many excellent textile properties and wearability and is widely used. It can be pure spun or blended with natural fibers such as cotton, wool, silk, hemp and other chemical fibers to make wool-like, cotton-like, silk like and hemp-like fabrics of various colors with good fastness, scratch resistance, easy washing and drying, no ironing, and good washing resistance.
- It has good elasticity and bulkiness and can also be used as cotton wadding. In industry, high-strength polyester can be used as tire cord, conveyor belts, fire water pipes, cables, fishing nets, etc. It can also be used as electrical insulating material, acid-resistant filter cloth, a paper-making blanket, etc. Polyester nonwovens can be used for interior decoration, carpet base cloth, manufacturing industrial cloth, flocking, lining, etc.
- Good value for the money
- Chemical resistance to oils and solvents
- Hydrolytic resistance when in contact with mild acids and bases
- A melting point that is fairly high and can withstand heat
- Very easy to recycle, even when it comes into contact with food
Disadvantages of polyester fiber:
- 1. Polyester fiber’s texture causes its first disadvantage: poor moisture absorption.
- 2. The air permeability is poor.
- 3. The third is that its dyeing performance is poor, and it needs to be dyed with disperse dyes under high temperatures.
- 4. Not very resistant to high pH values, especially strong bases
Why people choose polyester fiber:
1. Advantages of Polyester Fiber: Polyester fiber has high strength and elastic recovery capacity, so it is firm and durable, wrinkle-resistant, and iron-free.
2. It has excellent light resistance. In addition to being inferior to acrylic fiber, its light resistance is better than that of natural fiber fabrics, especially behind the glass. Its performance is nearly equivalent to that of acrylic fiber.
3. In addition, the polyester fabric has good resistance to various chemicals and is not damaged by acid or alkali and is not afraid of mold or moths.
To read more, please visit What is polyester fiber and its characteristics?
