Polyester Fibers. Polyester Fiber Production

Chemical production is one of the main sources of human benefits. Indeed, almost everything, from household items to clothing, is made and manufactured on the basis of this science.

A special role is given to various chemical fibers, which are used in numerous branches of science, technology and industry.

Chemical fiber classification

All chemical fibers can be divided into two large groups.

1. Artificial ones are those based on a natural polymer, but processing and spinning of threads directly takes place with the participation of physicochemical methods.
2. Synthetic - fibers that are created directly in laboratory (industrial) conditions. They are based on ordinary low molecular weight compounds converted to macromolecules as a result of polymerization reactions.

In turn, artificial and synthetic fibers also have their own classification and examples. Consider this for synthetic samples.

They can be divided into two large groups. The basis is the structure of the carbon chain and methods of forming bonds.

1. Synthetic carbochain fibers. The main chain is built strictly of carbon atoms, interconnected by ordinary sigma-type bonds. This group includes a fairly large number of samples. For example, polyacrylonitrile, polyethylene, polyvinyl chloride, polypropylene, polyvinyl alcohol.
2. Synthetic heterochain fibers. They differ in heteroatoms included in carbon macrochains - nitrogen, sulfur, phosphorus and others. This group includes such fibers: polyester, polyurethane, polyamide.

If we talk about the application in the textile industry, then the significance of the described representatives varies. So, artificial fibers are much more suitable for sewing clothes, bedding, towels and other household linen. Although there are exceptions when such a canvas finds application in technology.

Synthetic chemical fibers, on the contrary, are much more relevant in construction, engineering, industry than in everyday life. In more detail we will consider namely polyester yarns, fabrics from them and applications.

Polyester Fibers: General Description

From a chemical point of view, this product is the result of the interaction of terephthalic acid C ₈ H ₆ O ₄ and ethylene glycol, a dihydric alcohol C ₂ H ₆ O ₂ . As a result of a complex polymerization reaction, transparent or white crystals are formed, which have an important property - viscosity. To do this, they should be heated. It is on this feature that the production of fibers directly from a given substance is based.

The melting point of such materials is above 260 ⁰ C. This makes them very convenient to use for technical purposes. There are a number of special properties possessed by such fibers.

1. Polyester synthetic threads are able to withstand solutions of acids, alkalis.
2. Absolutely not soluble in water, organic solvents.
3. They are dielectrics, that is, they practically do not conduct electricity.
4. Products from them are durable, very wear-resistant and reliable.

Being completely synthetic in nature, these yarns are in many ways superior in technical and textile characteristics to many artificial fibers.

Production method

According to the previous description, terephthalic acid should be the basis for the production of polyester. However, its physical properties are somewhat inconvenient for a harmonious and rapid polymerization reaction with ethylene glycol, therefore, it is not used in its pure form, but an ester. Its name is dimethyl terephthalic ester of the same name acid, abbreviated as DMT.

Therefore, the production of polyester fiber consists of several successive chemical stages:

• the oxidation of a mixture of esters and paraxylene, that is, the preparation of the starting materials;
• etherification, that is, the production of DMT ester;
• distillation and purification of the obtained product;
• recrystallization of DMT in order to obtain pure raw materials.

The substance prepared according to this scheme is ready to enter the next cycle of transformations, the result of which will be polyester (polyester). This goes through two main stages.

1. Transesterification of DMT with Ethylene Glycol. The result is diglycol and low molecular weight polyesters.
2. Polycondensation of the products obtained in the first stage among themselves. As a result, viscous polyethylene terephthalate is formed.

Now it's up to the technical side. The substance is passed through special small dies, as if squeezing, and thereby receive fibers. When cooled, they crystallize. Further processing consists in drawing, peeling and coloring.

Material Names

In different countries, similar fibers are produced and used. Polyester synthetic threads in each state got their name, so they have a lot of synonyms. Consider what they are.

1. In Russia - polyester, polyester, lavsan.
2. In America, the dacron.
3. Great Britain - Terylene.
4. Japan - Teteron.
5. France - tergal.
   

However, whatever you call them, the properties remain the same and the scope, too.

Material polyester: properties

The main positive aspects of lavsan include qualities such as:

• poor creasing;
• incombustibility;
• light fastness;
• wear resistance;
• strength and softness, smoothness;
• resistance to the action of most organic solvents, as well as acids and alkalis;
• lack of abrasion;
• tissue does not support the development of living microorganisms (fungi, ticks, bacteria, and others);
• impact resistance;
• resistance to stretching.

Of course, such a set of positive characteristics cannot go unnoticed. That is why the areas of application of polyester products are very wide, covering most sectors of the economy.

However, there are also disadvantages. The following points should be attributed to them:

• hard to color, so juicy and bright shades in such fabrics are not found;
• strongly electrified, since the dielectrics themselves;
• if you take the true polyester not processed by special methods, then it will be a fairly tough material.

All of these disadvantages are easily eliminated by the addition of certain substances in the fiber manufacturing process. Therefore, they do not have significant significance.

Hollow fiber

This type of polyester yarn is very important in construction and engineering and is used there. Although there are exceptions. For example, such as holofiber, which has found refuge in the textile industry.

Hollow fibers are used for the manufacture of:

• fiberglass;
• building materials;
• heat insulating things;
• radio engineering products.

They are also used as filters in wastewater treatment. Thanks to its characteristics, Hollofiber has long since supplanted natural feathers and down from the textile industry. It has become the main type of filler for pillows, blankets, outerwear and other things.

Spherical Siliconized Fibers

This is the main product for the manufacture of the softest, most environmentally friendly and non-allergenic bedding. It is these fibers that are used as fillers for blankets and pillows.

Why are they used? This is due to the excellent technical characteristics.

1. Do not absorb moisture.
2. Resilient and elastic.
3. Machine washable, easy and convenient to care for and use.
4. They are odorless.
5. Do not cause allergies.
6. The development of microorganisms is impossible in them.
   

All this gives a spherical siliconized fiber as a filler of furniture, bedding and clothing a clear advantage over natural natural "colleagues": down, feather.

The disadvantages include a shorter service life compared to natural materials. However, the cost of such products is much lower.

Staple fiber

Among the polyester fibers, a special place is occupied by such a variety as staple threads. It is their synthetic fiber plant that produces in a larger volume than everyone else. This is due to the fact that such a product goes to the manufacture of yarn directly, and then material for sewing clothes, textiles and so on.

Often staple fiber is called a fiber formed from a harmonious combination of wool or cotton with polyester. Such symbiosis makes it possible to obtain the following types of materials:

• costume;
• coats;
• tulle;
• shorter;
• curtains;
• paid;
• felt;
• carpet;
• fur.

Obviously, what products can be sewn and made from such components.

Polyester technical thread

Such fibers are used for the manufacture of the following products:

• fishing nets and trawls;
• ropes and ropes;
• hoses for oil products;
• canvas;
• conveyor belt;
• seat belts and drive belts;
• tire cord;
• thermal insulation and filter materials.

Such filaments include the hollow fiber discussed above.

Polyester Products

What other products can be made of polyester? The special significance of such materials that are used as filler, we have already described above. I just want to add that holofiber allows you to get the softest and most comfortable pillow and warm and light blanket. Polyester fiber in the textile business is simply irreplaceable and rises higher and higher in value every year.

Dacron is also used to obtain the following types of fabrics:

• taffeta;
• crepe;
• knitwear;
• crimped;
• Melan.

They make clothes, tulle and curtains, stage attributes, etc.

Another type of practical human activity in which polyesters are used is surgery. Medicine has considered the possibility of manufacturing artificial blood vessels and surgical sutures from polyester. This, of course, facilitates many life-saving operations.

Product and fiber reviews

Considering that, in addition to the positive characteristics, polyester-based materials still have drawbacks, not all people are satisfied with the products. When it comes to construction applications, there can be no dispute here: lavsan is the leader. However, speaking of textile products and clothing, differences should also be noted. Negative opinions also consistently receive polyester fiber. Reviews of this kind are based on the shortcomings of the fabric itself - electrification and limited service life.

Nevertheless, most people tend to consider polyester one of the most comfortable, beautiful and high-quality materials of our time. Therefore, clothes, household items and bedding from these materials only gain popularity over the years.

If you look at reviews about pillows and blankets based on polyester, then the vast majority of them will still be positive, which is completely justified and fair.