The Application of Polyester and Novel Polyester Fibers in the Nonwoven Field

Abstract: The paper provides an overview of the application prospects of polyester and new types of polyester fibers such as PTT and PBT in the nonwoven sector. It introduces the development status of new products and functional fibers, as well as new types of polyester fibers, at Shanghai Petrochemical Company. It suggests that the development of polyester and new polyester fibers in the nonwoven field has three major trends. With the continuous improvement and development of the performance and variety of polyester and new fibers, their application in the nonwoven field will see significant growth.

Keywords: Polyester, Novel polyester fibers, Nonwoven, Market, Application

Section 1: Overview In the various major industries of textiles, the development of nonwoven in China started relatively late. In the early 1980s, the national annual output was less than 10,000 tons. However, it has developed at an astonishing rate, with China’s production of various nonwovens exceeding 700,000 tons in 2003. In the production of nonwovens, chemical fibers account for 85% of the fiber raw materials used, with natural fibers making up 15%. The most used chemical fiber is polyester fiber (accounting for about half of the total amount), followed by polypropylene, viscose, polyvinyl alcohol fiber, and a small amount of polyamide fiber. Among them, PET fiber made from polyester (PET) has a consumption of about 260,000 tons. In recent years, the development of spunbonded and hydroentangled nonwovens has been particularly rapid.

Section 2: The Application of Polyester and Novel Polyester Fibers in the Nonwoven Field

The development of polyester and novel polyester fibers in the nonwoven field has three major trends: First, the development of specialized series suitable for nonwoven processing techniques and product requirements; Second, the differentiation and functionalization in line with the requirements of the end products, such as antibacterial, flame retardant, aromatic, and warming properties; Third, the “green” trend that complies with environmental and safety requirements during processing and product use.

Currently, there are still obstacles to overcome in the development of functional fiber varieties and quality suitable for nonwoven processing requirements, such as bicomponent, ultra-fine, high-temperature resistant, flame retardant, antistatic, and antibacterial deodorant fibers. Therefore, the development of functional nonwoven products has been somewhat limited.

Functional nonwovens belong to high value-added, high-tech nonwoven products. Their production requires solving issues in three areas: raw materials, equipment, and processes. In China, this is still in its infancy.

2.1 Specialization of Polyester in Nonwoven Application Field

2.1.1 Polyester staple fiber for needle punching and hydroentanglement processing technology

The characteristics of polyester staple fiber used in weaving processing are that the fiber has a high tenacity corresponding to 10% elongation to achieve the efficiency of the textile processing process; the ideal fiber surface treatment, especially spinnability (opening performance, yarn formation performance, antistatic performance, fiber binding performance, etc.). The polyester staple fiber used in nonwovens should have the same characteristics as the fiber used for textile products in terms of physical and mechanical properties and appearance quality, such as high tensile strength, low dry heat shrinkage rate, appropriate crimp shape and firmness, as well as low defects and long fiber content.

The feature of the dry method needle punching production line is that the fiber undergoes thousands or even tens of thousands of relative movements with metal needles during the production process, so it requires a low friction coefficient between the fiber and metal; the fiber should have a higher friction coefficient with other fibers to improve the interlacing effect during the needle punching process, thereby increasing the strength of the fiber web; the fiber should also have hydrophilicity, antistatic properties, etc., to meet the spinnability requirements of nonwoven enterprises.

In the hydroentanglement production process, the fiber should have good hydrophilicity, low pollution, and low foaming properties to extend the use cycle of water circulation and the replacement cycle of filter nets; the fiber should have good opening characteristics and appropriate crimp performance to improve the interlacing effect and increase the strength of nonwovens.

2.1.2 High Shrinkage Fibers for High-Density Nonwovens High shrinkage polyester fibers are typically obtained by modifying crystalline polyester. There are two main pathways to produce high shrinkage polyester: one is through special spinning and stretching processes; the other is through chemical modification methods.

Shanghai Petrochemical Company’s Polyester Division uses physical methods and chemical modification to make high shrinkage polyester staple fibers that can shrink up to 80% in hot water at 90°C. The fiber’s denier range, based on the requirements of the final product, is generally between 1.40 to 3.33dtex, mainly used for artificial leather high-density base cloth and for imitation wool fabrics. The main contribution of high shrinkage fibers in nonwovens is to utilize the rapid shrinkage characteristics of the fibers under hot water or hot air conditions to achieve controlled longitudinal and transverse shrinkage of the nonwoven, ultimately increasing the density of the nonwoven.

2.1.3 Hollow Short Fibers for Filling Materials Since the late 1980s, domestic production of filling material polyester hollow fibers using the asymmetric spinning cooling forming method has reached an economic scale. The product variety and technical content have also developed from ordinary single hollow to multiple hollow, surface treatment (to give good elasticity and fluffiness), colored, and functional (such as far-infrared, antibacterial, aromatic, insect repellent, mosquito repellent, etc.). The raw material has developed from a single component to a bicomponent, and the spinning has evolved from traditional chip spinning to direct composite spinning.

Due to the abundant raw material sources of hollow short fibers, and their good fluffiness, high elasticity, and warmth retention, they are an ideal filling material and are gradually replacing natural fibers for pillow cores, mattress pads, quilt covers, bedspreads, sleeping bags, ski jackets, skating suits, sofa cushions, and soft toy fillings. In Japan and South Korea, furniture and bedding products have already replaced more than 95% of synthetic sponge and cotton with hollow polyester short fibers.

2.1.4 Polyester Ultra-Short Fibers for Wet-Laying Papermaking Since the 1980s, the production technology of polyester ultra-short fibers has gradually matured. With the development of polyester production technology and the reduction of polyester raw material costs, the application fields of polyester ultra-short fibers have been continuously developed and have played a very important role in the paper industry and nonwoven filter fields.

The key to the technology of this product can be summarized into six main points: special spinning molding and post-treatment stretching setting technology required for special physical mechanical properties, process control technology for high uniformity of appearance and internal quality, cutting technology for lengths less than 6mm, high dispersibility technology in other media, fiber surface treatment technology, and special requirements for fiber additives technology.

Since the 1990s, polyester ultra-short fibers have made breakthrough progress in the application of wet-laid nonwoven filter materials. Due to polyester’s high melting point (265°C) and high tensile strength, as well as its resistance to the dissolution and corrosion of oils and some chemical solvents, it has been used in the filtration of lubricating oils for automotive and mechanical processing equipment, food processing, pharmaceutical manufacturing, and air filtration.

Polyester ultra-short fibers, according to different end uses, adopt special manufacturing methods to reflect the dispersibility, thermal shrinkage stability, and hygiene requirements of ultra-short fibers in other media. The denier range can be from 0.7 to 3dtex, and the cutting length is generally 2, 4, 6mm, etc. The color can be special white, fluorescent, colored. The fiber surface is treated with special additives certified by the FDA.

2.1.5 Polyester Geotextile Fibers for Special Use According to the application and processing requirements of polyester fibers for geotextiles, they can be roughly divided into two categories: one is for carding web formation, and the other is for air-laying. The first requirement for carding web formation is the cardability of the fiber (basically similar to the “steel wire car” in cotton spinning equipment), so the type of oil agent, oil content, fiber length, and crimp state have a great impact. The most critical factor for air-laying is the type of oil agent for the fiber.

The physical and mechanical properties and heat shrinkage rate of the fiber are also key to the quality and processing efficiency of the needle-punched nonwoven product. Nonwovens require fibers with high breaking strength (high tensile strength and large breaking elongation) to improve the tearing strength and pressure strength (high toughness) of the product; at the same time, it is hoped that the dry heat shrinkage rate at 180°C is as small as possible, and the CV% can be less than 6%, to keep the product’s length and width dimensions as stable as possible during the heat treatment process. Domestically, in the 1980s and 1990s, ordinary (low strength, high extension) polyester fibers produced from recycled polyester materials were used, and the fiber quality was very unstable, which brought a negative impact on the quality and technical progress of geotextiles. Since the 1990s, many domestic enterprises have started to pay attention to the quality requirements of polyester fibers for geotextiles, and according to the application fields of geotextiles, they have developed and gradually established a series of varieties of polyester staple fibers for nonwoven geotextiles, taking a welcome step towards specialization and series specifications. The main varieties and specifications are shown in Table 2.

Table 2: Different Specifications of Nonwoven Geotextile Polyester Fibers

Use Case	Function	Product Specification (g/m²)	Fiber Specification
Sea and Shore Dikes	Filtration, Drainage, Reinforcement	800-1500	3.33-5.55 dtex, Medium to High Tenacity, Low Elongation to High Tenacity
Road (Lightweight)	Separation and Reinforcement	200	5.55-7.77 dtex
Road (Medium Weight)		300	7.77-11.1 dtex
Road (Heavyweight)		350-400	11.1-16.5 dtex
Railway (Track, Subgrade)	Separation, Reinforcement, Drainage	270	3.33-5.55 dtex
Rock Structures, Dams	Filtration, Drainage	350-600	5.55-11.1 dtex
Tunnel Reinforcement		800-1500	11.1-18.7 dtex

2.1.6 Fine and Ultra-Fine Fibers

(1) Fine Fibers from Conventional Spinning Generally speaking, under the same nonwoven weight conditions, the finer the fiber denier, the greater the number of fibers, the increased contact points and contact area between fibers, and the increased relative sliding resistance between fibers, thereby increasing the strength of the nonwoven. The fiber denier is an important indicator of carding ability. The carding ability of the carding machine mainly depends on the fiber denier. Fibers with a denier too fine, for example, below 1.1 dtex, are relatively difficult to card and form a web. However, the finer the fiber denier, the better the uniformity of the web. Nonwovens that usually require good uniformity, smoothness, and density mostly use fine denier fibers.

The fine fibers spun by conventional methods have a denier range of 0.56 to 0.89 dtex. The chemical fiber industry can already produce specialized fibers suitable for nonwovens through direct spinning and slice spinning and other traditional processes. Compared with composite ultra-fine spinning, the cost is greatly reduced, and the uniformity of the fibers is relatively better than that of ultra-fine fibers.

(2) Ultra-Fine Fibers from Composite Spinning Currently, the production of polyester ultra-fine fibers mainly uses the island and segment splitting methods. Generally, they are processed by needling and water jetting for nonwoven production of artificial leather base cloth. The material composition of “sea” and “island” has also been improved. In the past, the “island” material was nylon or polyester, and the “sea” used polystyrene. Since the dissolution of polystyrene requires trichloroethylene as a solvent, which is toxic and has difficulties in solvent recovery, etc. Currently, the “sea” uses a hydrolyzable polyester (Co-PET with high content of IPA, etc.), which can be decomposed by about 30% alkali solution at around 80°C. The processing is carried out in the bath tank after the artificial leather is formed, thus providing an industrial feasible method for the application of island ultra-fine fibers.

The ultra-fine fibers of the segment splitting method generally use composite fibers of polyester or modified polyester and nylon. During and after the water jetting or needling process, they are ultra-fine through mechanical friction methods.

2.2 Differentiation and Functionalization

2.2.1 Flame-Retardant Fibers The flame-retardant modification of polyester (without considering the flame-retardant finishing of the fabric) has two methods: blending and copolymerization. Blending modification is to add blending flame retardants during the manufacturing process of polyester chips to make flame-retardant chips or to add flame retardants when spinning to blend with the polyester melt and make blending flame-retardant fibers; copolymerization is to add copolymer flame retardants as monomers during the polyester manufacturing process through copolymerization to make flame-retardant polyester.

The flame-retardant behavior of flame retardants mainly includes cooling, dilution, forming an isolation film, and terminating the free radical chain reaction, etc. The first three are physical methods, and the last one is a chemical process. The flame-retardant mechanism of phosphorus flame retardants is mainly to form an isolation film to achieve flame retardation. There are two ways to form an isolation film:

(1) The thermal degradation products of the flame retardant promote the rapid dehydration and carbonization of the polymer surface, forming a carbonized layer. Since elemental carbon does not undergo evaporative combustion and decomposition combustion that produces flames, it has a flame-retardant protective effect. The flame-retardant effect of phosphorus flame retardants on oxygen-containing polymers is achieved in this way. The reason is that the final product obtained by the thermal decomposition of phosphorus-containing compounds is polyphosphoric acid, which is a strong dehydrating agent.

(2) Phosphorus flame retardants decompose at combustion temperatures to form a non-volatile glassy substance that coats the surface of the polymer. This dense protective layer plays the role of an isolation layer. Halogenated phosphorus flame retardants have this characteristic. The intumescent flame-retardant system based on ammonium polyphosphate is a typical representative of this mechanism.

2.2.2 Aroma Fibers Aroma fibers are made by the skin-core composite method, adding fragrances carried by a special polymer in the core layer. Since the core layer is spun at a lower temperature, the volatilization of the fragrance during the spinning process is minimized. After the fiber is formed, the fragrance gradually emanates along the cross-section of the fiber axis, achieving a long-lasting fragrance effect. Unlike ordinary textile processing, the post-treatment of nonwovens is relatively simple, so the fragrance of natural spices can be maximized to avoid damage from chemical processing agents and processes, as well as avoiding the impact of high-temperature dyeing processes on the fragrance retention time.

2.2.3 Negative Oxygen Ion Emitting Fibers Incorporating special inorganic additives (tourmaline) into the PET melt can confer four major properties and functions to polyester fibers. Firstly, it can provide the fibers with far-infrared warming capabilities; secondly, it offers significant odor elimination effects; thirdly, it has the function of emitting negative oxygen ions, capable of generating negative oxygen ions at room temperature; and fourthly, it possesses certain antibacterial effects.

Tourmaline is a boron-containing cyclic silicate material characterized by aluminum, sodium, iron, and lithium, known for its thermoelectric and piezoelectric properties. The vibration of its polar ions causes changes in the dipole moment, resulting in the emission of electromagnetic radiation in the far-infrared band, which has a strong broadband radiation effect. Infrared radiation can cause thermal effects and resonant absorption in the human body. The health benefits for the human body include promoting metabolism, enhancing tissue regeneration, and accelerating functional recovery; it can cause blood vessels to dilate and blood flow to quicken, improving microcirculation; and it can boost immunity, playing a role in disease prevention and resistance.

When external factors act on electrically neutral gas molecules, the outer electrons of the gas molecules will break free from the nucleus’s grip, jumping out of the orbit. At this point, the gas molecule becomes positively charged, and the freed electrons will quickly attach to other gas molecules or atoms, becoming air negative ions.

This product can be used as a filling material, in the form of single hollow, multi-hollow, and special-shaped cross-sections to increase the contact area between the fiber and air, enhancing and reinforcing the “magical” effect. It is used in the core of medical textiles and can also be used for indoor bedding, car seats, etc.

2.2.4 Antimicrobial Fibers Antimicrobial and deodorant polyester, made by blending high-efficiency antimicrobial agents or zeolite particles containing metal ions with PET in the spinning solution or melt, can effectively inhibit and kill microorganisms (such as fungi and bacteria) attached to the fiber surface. It has good durability and safety in use (without affecting the normal functions of the human body). Especially polyester made with zeolite particles containing metal ions, in addition to having antimicrobial and deodorant functions, also adds some new features, such as fabric drape, anti-inflammatory, analgesic, promoting blood circulation in the human body, and accelerating wound healing, and other medical and health care functions.

Antimicrobial and deodorant fibers can be made by incorporating antimicrobial and deodorant agents into the spinning solution or melt, or by combining with the post-processing of fibers. The most commonly used antimicrobial agents for the antimicrobial treatment of polyester and its fabrics are five categories: metal, quaternary ammonium salts, phenols, halogens, and organic nitrogen, among which metal and quaternary ammonium salts are the most commonly used. Antimicrobial and deodorant fiber density is between 1.5 and 16.6 dtex, length is between 38 and 76 mm, and the bacterial reduction rate can reach 97%, widely used in sanitary, medical materials, and special requirements for filter materials.

2.3 Safety and Environmental Protection

2.3.1 Degradable Polyester Fibers Degradable polyester fibers refer to a class of polyester fibers that undergo significant changes in their chemical structure under specific environmental conditions, leading to a loss of certain properties. According to the environmental conditions that cause degradation, they can be classified into photodegradable, biodegradable, chemically degradable, and combinations of the above three types. Currently, the preparation of degradable polyester raw materials often involves copolymerization with biodegradable aliphatic polyesters such as polycaprolactone (PCL) or polybutylene succinate (PBS). Another method is blending with biodegradable polymers such as polylactic acid (PLA) or starch. Today, with the frequent occurrence of various infectious diseases between humans and animals, and the increasing awareness of environmental protection, to ensure sustainable economic development and maintain a safe living environment and clean living space, countries around the world pay great attention to the research and development of environmental protection technology and products. The development and research of degradable polyester fibers in the application of nonwovens will definitely have a broader prospect.

2.3.2 Low-Melting Point Skin-Core Composite Fibers Low-melting point polyester composite fibers are produced by composite spinning of general polyester and specially designed polyester, which can melt and bond with other fibers at a lower temperature than general polyester. Low-melting point fibers can be used both in combination with other materials and alone. They are mainly used for wadding, lining, sanitary materials, filter materials, and various industrial nonwovens.

Low-melting point fibers are usually made by the skin-core composite method. The core is made of conventional polyester, and the skin is made of low-melting point polyester with a melting point of about 130°C. The skin layer can also be made of polyethylene (PE) or polypropylene (PP). The bonding strength of the low-melting point composite fiber is mainly determined by the structure of the low-melting point component (skin layer), the proportion of the fiber surface formed by the low-melting point component, and the thickness of the low-melting point component’s layer, which is examined by the peel strength indicator. This fiber can maintain the strength of general low-melting point fibers at high temperatures in the normal temperature environment, and has good durability and environmental affinity.

2.3.3 Whitening Fibers Since the 1980s, the United States has added whitening agents to polyester to increase the whiteness of the fibers, which can effectively enhance the brightness of dyeing, improve the efficiency in the printing and dyeing process, effectively save water resources, and reduce the wastewater discharge during the printing, dyeing, and finishing of fabrics, which is to some extent a “green” product. 90% of polyester staple fibers in the U.S. market contain OB-1 (chemical name 2,2-diphenylvinyl). The main optical brightener OB-1 produced by Eastman Chemical Company in the United States (Chinese mainland commodity name “Tebai Li”) has FDA certification. Shanghai Petrochemical Company has started mass production of optical brightening fibers containing OB-1 and can produce fibers with different denier ranges according to customer requirements, and can also provide products with different whiteness according to customer requirements.

From an overall cost perspective, using fiber whitening methods can save more than 60% of processing costs, effectively reduce wastewater discharge, and thus produce good social benefits. The main function of the brightener is to absorb the invisible ultraviolet A band (320-400nm) in sunlight and convert it into visible light reflected at wavelengths of 420-440nm. The intensity of the reflected visible light exceeds the projected visible light intensity by about 15%, making the fibers have a significant whiteness. Recently, in the nonwoven field, both filling materials and water-jetted and needled products have shown a trend of using whitening fibers.

2.4 Novel Polyester Fibers for Nonwoven Applications

2.4.1 PTT Fibers PTT (Polytrimethylene Terephthalate) fibers combine the rigidity of PET fibers with the flexibility of PBT (Polybutylene Terephthalate) fibers, possessing the advantages of both polyester and polyamide fibers, especially their excellent elasticity and dyeability, which has attracted attention in the fiber material industry. In recent years, PTT fibers have begun to be produced and developed abroad and have been listed as one of the new fibers of the 21st century. PTT fibers can not only be used in the carpet and textile markets but also have great development prospects in the fields of polyester dyeing assistants, needle-punched nonwovens, thermoplastic engineering plastics, and films.

The outstanding advantage of PTT fibers is their excellent tensile elasticity. Studies have been conducted on the stretch recovery of PET, PBT, and PTT fibers, and it has been found that the recovery order of these fibers is PTT > PBT > PET, which is related to the lattice conformation of the polymer chains. The polymer chains of PET fibers are basically fully extended, and the elongation of fully stretched fibers is not large (about 6%), which is the reason for the high initial modulus of PET fibers. PTT fibers have a low initial modulus, and the change in the initial modulus is not significant as the stretch ratio increases. Under the action of 2.5cN/dtex, the repeated stretching test of PTT fibers shows that the fully recoverable elongation rate is 20%.

PTT fibers, when stretched to 20% or equivalent to a breaking strength of 2.5 cN/dtex, still exhibit reversibility in stretching. This characteristic opens up new application fields for PTT fibers. By fully utilizing the structure and properties of PTT fibers, hollow parallel composite fibers can be made by the parallel composite method for use in nonwoven filling materials. Taking advantage of PTT fibers’ relatively low-temperature dyeing performance compared to PET fibers, they can replace some polyamide fibers in nonwoven fields that require low-temperature dyeing.

2.4.2 PBT Fibers With the development of differentiated fibers, the value of PBT as a fiber has gradually been recognized. PBT’s crystallization speed is 10 times faster than PET’s, and its fibers have excellent elongation, elastic recovery, softness, and dyeability. They can also be used in composite spinning with PET and polypropylene or blended spinning with PET, polyamide, and polypropylene.

The polymerization, spinning, and processing technology for PBT fibers are essentially the same as those for regular polyester, and only minor modifications are needed to produce PBT fibers using polyester production equipment.

In summary, PBT fibers have the following characteristics:

1. They have good durability, dimensional stability, and excellent elasticity, which is not affected by humidity.
2. The fibers and their products are soft to the touch, with good moisture absorption, wear resistance, and good fiber curliness. They have excellent stretch and compression elasticity, and their elastic recovery rate is better than that of polyester. They have special extensibility under both dry and wet conditions, and their elasticity is not affected by changes in ambient temperature. The price is much lower than that of spandex.
3. They have excellent dyeing properties and can be dyed with common disperse dyes at atmospheric pressure and boiling, without the need for carriers. The resulting fiber color is bright, with good color fastness and chlorine resistance.
4. They have excellent resistance to chemicals, light, and heat.
5. PBT and PET composite fibers have fine and dense three-dimensional curls, superior elasticity, soft feel, and excellent dyeing properties. They are ideal materials for imitation wool and down, providing comfort when worn.

2.4.3 PEN Fibers PEN (Polyethylene Naphthalate) is an important member of the polyester family, made by the condensation of 2,6-Naphthalenedicarboxylic acid (NDC) or 2,6-Naphthalenedicarboxylic dimethyl ester (DMN) with Ethylene Glycol (EG). It is a polymer with excellent properties. The chemical structure of PEN is similar to that of PET, but the difference is that PEN has a more rigid naphthalene ring in the molecular chain instead of the benzene ring in PET. The naphthalene ring structure endows PEN with higher mechanical properties, gas barrier properties, chemical stability, and heat, UV, and radiation resistance than PET. PEN has a very broad application prospect in the fields of fibers, films, packaging materials, and engineering plastics.

PEN has good chemical stability, is stable to organic solvents and chemicals, and has better acid and alkali resistance than PET. Due to PEN’s good gas tightness and relatively high molecular weight, its tendency to exude oligomers at actual use temperatures is lower than PET’s, and the amount of low-level aldehydes released during decomposition at processing temperatures higher than PET is also less than that of PET.

After being placed in a humid air at 130°C for 500 hours, the elongation of PEN only decreases by 10%; after being placed in a dry air at 180°C for 10 hours, the elongation can still maintain 50%; whereas PET would become brittle and lose its value under the same conditions. PEN’s melting point is 265°C, similar to PET’s, and its glass transition temperature is above 120°C, about 50°C higher than PET’s.

PEN also has excellent mechanical properties. The Young’s modulus and tensile modulus of PEN are 50% higher than those of PET. The mechanical properties of PEN are stable, and even under high temperature and high pressure, its modulus, strength, creep, and lifespan can still maintain considerable stability. PEN also has excellent electrical properties, comparable to PET’s dielectric constant, volume resistivity, and conductivity, but its conductivity changes less with temperature.

Currently, PEN fibers used in the nonwoven field are mainly as filter materials. Environmental filter materials are generally used in both dry and humid environments, requiring excellent heat resistance, chemical corrosion resistance, moisture hydrolysis resistance, and wear resistance. Filter materials made from PEN fibers have excellent filtration performance, comparable to polyphenylene sulfide (PPS) fibers. The insulation and thermal insulation indicators of PEN filter materials can reach Class F standards and can be used continuously in high-temperature environments of 160°C.

PEN filter materials have excellent tensile strength over a wide pH range and will gradually replace PET screens, gaining wider application in the papermaking screen field.

3. Development Trends of Polyester Fibers in the Nonwoven Field

Statistics show that the global production of nonwoven rolls (finished products) was 800,000 tons in 1983, and it is predicted to reach 3.7 million tons by 2005 and 4 million tons by 2007. The output of some major companies accounts for 75% of the total global production, among which DuPont, PGI, Kimberly-Clark, Johns Manville, Dexter Lydace, Foss, Freudenberg, BBA Group, BP Amoco, Fibertex, and Acordis have an absolute advantage in the global market. Nonwoven products account for 99% of the total consumption, including 63% polypropylene, 23% polyester, 8% viscose, 2% acrylic, 1.5% nylon, and 3% other special fibers.

The proportion of chemical fiber consumption in nonwovens to the total chemical fiber consumption was 3.7% in 1970 and is expected to reach 10% by 2005 and 10.4% by 2007. The fastest-growing applications for nonwovens are sanitary absorbent materials (sanitary pads, flannel, diapers), medical textiles, automotive textiles, footwear, artificial leather, and some special markets.

The development of the industry, especially in China, Southeast Asia, Latin America, and the Middle East, is one of the reasons for the increased consumption of nonwoven industry. The development of polyester fiber production technology, continuous optimization of the production process, reduction of production costs, improvement of product quality; the development of nonwoven processing technology and the integration of raw materials no longer have obvious industry boundaries. Specialized fibers that have matured according to the requirements of the end users and the characteristics of the processing industry have gradually formed standards; the industrial development of new polyesters (PTT, PBT, PEN) has been successful, etc., all of which have created a good foundation for the development of nonwoven products and the overall function and advantages of polyester fibers.

As one of the most consumed chemical fibers in nonwovens, the application of polyester fibers in this field will also continue to expand with the continuous development of the nonwoven industry. With the continuous improvement and development of the performance and variety of polyester and new polyester fibers, their application in the nonwoven field will also present a more colorful scene.