Is chemical fiber so unpopular? After reading this article, you will change your mind about it

Clothes, shoes, socks, household items, textiles are indispensable in our daily life. When purchasing, in addition to looking at the color and style, consumers also have another very important criterion, which is the material. In general, natural materials such as silk, cotton, linen, and wool are very popular with the public. Correspondingly, chemical fibers and artificial materials with words such as nylon, nylon, and viscose will be ruthlessly rejected. But what are the advantages of pure natural fabrics? Are chemical and artificial fibers really bad? Is it time to change these inherent concepts?

Before answering these questions, let me give you some basic knowledge: the most basic unit of textiles is fiber. According to the source, textile fibers are divided into natural fibers and chemical fibers (see Figure 1). This picture is very important and will be used later.

Figure 1 Textile fiber classification

(Note: Hemp used as textile fiber is a type of hemp variety with a very low content of the active ingredient cannabinol, and is not a prohibited variety. In my country, this type of fiber hemp is usually referred to as "Hanma", which is the transliteration of the English word Hemp, to avoid market misunderstandings.)

01

Natural fibers with a long history

Solved the problem of human beings being naked

Natural fibers provided the earliest materials for covering the body and keeping warm in human development. 5,000 years ago in the Indian subcontinent, people began to spin yarn with cotton fibers; in the Nile River Basin in ancient Egypt, flax was widely planted by humans to make clothes; more than 5,000 years ago, the working people of my country began to plant mulberry trees, raise silkworms, draw silk, and weave silk, forming a unique silk clothing culture. At present, cotton fiber, linen fiber, wool fiber and silk fiber (referred to as cotton, linen, silk and wool) are still the main natural materials for people's daily clothing and textiles. These natural materials have their own advantages, but they also have certain defects.

02

Amazing production of chemical fibers

and artificial fibers that do not rely on petroleum

Different from the natural fibers given to humans by animals and plants in nature, chemical fibers are a type of fibers made by chemical methods. Chemical fibers are divided into chemical synthetic fibers, artificial fibers (usually called regenerated fibers), and inorganic fibers according to their raw materials and components (see Figure 1). The history of chemical fibers is only a short 100 years. In 1893, humans invented the production method of the first chemical fiber, viscose fiber, and since then the family of chemical fibers has continued to expand.

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How should we distinguish between man-made fibers with very "academic" names? The fibers ending with "纶" that we often see when buying textiles and clothing are generally chemical synthetic fibers, such as polyester, nylon, acrylic, spandex, polypropylene, etc. Synthetic fibers are organic polymer compounds synthesized by addition polymerization or condensation polymerization using small molecule organic compounds as raw materials. Most synthetic fibers come from petroleum. The petrochemical system extracts and separates the small molecule organic compounds needed to produce such fibers. Chemical synthetic fibers made from petroleum raw materials are sometimes also called "petroleum-based fibers." In terms of output, synthetic fibers are the largest category in the chemical fiber and even the entire textile fiber family. In 2019, China's synthetic fiber output reached more than 54 million tons, accounting for 92.8% of the chemical fiber family; while China's cotton output was 5.9 million tons and silk output was only 68,000 tons during the same period.

Artificial fibers are made from natural polymer compounds such as cellulose and protein, which are chemically processed into concentrated polymer solutions, and then spun and post-processed to produce textile fibers. Regenerated fibers are often referred to as "artificial fibers". The most common regenerated fibers in clothing are viscose fibers (also known as rayon or artificial cotton), modal fibers, and lyocell fibers (also known as Tencel). Artificial fibers directly use natural polymer compounds, do not consume petroleum resources, and have different fiber properties from chemical synthetic fibers.

03

Disadvantages are also shining points

Chemical fibers have been working hard

The emergence of chemical fibers has greatly enriched the varieties and properties of textiles and clothing. The chemical fibers used in common textiles and clothing have their own advantages and disadvantages, giving the products some functions and characteristics that are different from natural fiber materials.

Although chemical fibers have their own shortcomings, these "shortcomings" are often fully utilized to develop specific products. For example, the most notable feature of polyester is its poor hydrophilicity, which makes polyester fabrics easy to dry. Many high-quality quick-drying sportswear are made of ultrafine polyester. After the ultrafine fibers are woven into fabrics, the capillary siphon effect is formed between the fibers, which accelerates the evaporation of sweat on the fiber surface and keeps the human body surface dry and comfortable during exercise; and the fibrillation characteristics of lyocell fibers are used to produce peach-skin-style fabrics.

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Many consumers have a misunderstanding that natural materials such as cotton, linen, silk and wool are the best fabric materials, but this concept should actually change.

my country is a strong country in the production and research and development of chemical fibers, and the output of chemical fibers accounts for more than 70% of the world's total. With the advancement of technology and changes in consumer concepts, chemical fibers are also constantly improving, mainly in terms of functionality and comfort. Taking polyester, which has the largest output, as an example, the structural characteristics of polyester lead to its poor hygroscopicity and easy static electricity. In order to improve this disadvantage of polyester, the R&D personnel started from improving the structure of the fiber and used a variety of physical and chemical methods to transform the internal and external structures of conventional polyester. On the basis of conventional polyester, PBT (polybutylene terephthalate) fiber and PTT (polytrimethylene terephthalate) fiber were developed by modifying the molecular structure. PBT fiber is better than conventional polyester fiber in softness, wear resistance and elasticity, and it is easier to dye; PTT fiber has better resilience, is easy to dye, has high color fastness, and has the advantages of chlorine resistance and UV resistance.

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Researchers have also developed " cotton-like polyester ", which is a polyester with the advantages of cotton fiber, and its hydrophilicity has been significantly improved. Cashmere-like polyester is a polyester with the characteristics of wool fiber developed by learning from the experience of cotton-like polyester. Its surface and cross-section are both honeycomb microporous structures, with a fineness close to cashmere, and has a soft and delicate feel like cashmere and good moisture absorption and breathability. Cashmere-like polyester fiber can be spun pure or blended with other fibers, and its price is only 1/3 of that of natural cashmere fiber. Through various process methods, researchers have also developed polyester with differentiated functions such as moisture absorption and quick drying, anti-pilling, antibacterial, anti-ultraviolet, and flame retardant, so that it can meet consumers' demand for functional clothing.

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04

Complement each other's strengths and weaknesses

Natural + Chemical 1+1＞2

After the characteristics of natural fibers and chemical fibers are fully understood, people often combine the advantages of natural fibers and chemical fibers through blending or interweaving in product development, thus achieving the effect of 1+1>2. The most common example is polyester-cotton blended fabric, which is usually made of 65% polyester and 35% cotton fiber. The strength, wear resistance and shape retention of polyester-cotton blended fabric are better than those of pure cotton fabric, while also having a certain degree of moisture absorption and soft feel.

For example: traditional jeans are woven with pure cotton coarse yarn. Although it has good moisture absorption, it lacks elasticity and does not fit well. High-stretch jeans are made of cotton yarn and spandex yarn. After highly elastic spandex yarn (usually 3%-5%) is interwoven, elastic denim fabric can be obtained, which is close to the body and comfortable, adding comfort while ensuring the special style of denim clothing.

The picture comes from the Internet

Let's take another example: the picture above is a product ingredient description of sports socks on the market. The fabric of this pair of sports socks is a blend of four fibers: cotton, polyester fiber (polyester), hemp and spandex. Cotton fiber ensures the skin-friendly and moisture-absorbing functions of sports socks; polyester fiber improves the strength and wear resistance of sports socks; hemp fiber has inherent antibacterial properties, providing sports socks with antibacterial and deodorizing functions; spandex provides the elasticity of sports socks, making them fit the foot more comfortably. Such a pair of sports socks can be said to combine the characteristics of four fibers to provide the wearer with the best experience.

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05

What is understanding? By “ checking, touching, and asking ”

What to choose? It should meet the needs of the scene

According to the requirements of the national mandatory standards, the washing labels of textiles and clothing must clearly indicate the material composition of the product. Consumers can directly look at the washing labels as a reference when purchasing in daily life. In addition, touch and visual inspection are also methods that consumers can use to identify fiber materials, but this requires consumers to accumulate some experience in daily life.

In addition, consumers can also get to know the material of the product by asking the salesperson. The salespersons of textiles and clothing of regular brands have received professional training on fiber material knowledge and can provide consumers with purchase suggestions. Other fiber identification methods include microscopic observation, combustion method, dissolution method, etc. These methods are generally used in laboratory testing, which will cause certain damage to the product and are not suitable for daily purchases.

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As the market classification of textile and clothing products becomes more and more refined, consumers can follow a "scenario demand" law when making daily purchases, that is, to choose textiles and clothing according to the needs of the use scenario. In fact, at the beginning of the design and production of textiles and clothing, R&D and design personnel have fully considered the use scenarios of the products when selecting the materials of the products: the physiological changes and needs of the human body (such as sweating, warmth, breathability, waterproofing, antibacterial, sun protection, etc.) and the characteristics of the external environment (such as heat, cold, rain, snow, strong wind, sun exposure, etc.).

For example, cotton, silk, and linen fabrics are generally chosen for daily wear in summer; when exercising a lot, sportswear made of chemical fibers with moisture-absorbing and quick-drying functions should be selected; cotton and modal fabrics can be selected for daily close-fitting clothing, which are skin-friendly; outerwear can be made of polyester and nylon, especially outdoor clothing, as the high strength and wear resistance of these chemical fibers can provide a better wearing experience; home textile products such as bedding and towels have higher requirements for skin-friendliness and moisture absorption, and it is generally recommended that you choose cotton; home textile products such as quilts that have fillings can be made of cotton fibers, wool fibers, and highly curled chemical staple fibers, as these materials are very outstanding in terms of warmth retention.

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Author: Song Lidan, Consulting Engineer, Industrial Research Department, China Textile Construction Planning Institute

Review | Zhang Jie, Chief Engineer, China Textile Construction Planning Institute

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