At all times the textile industry has beenone of the most important sectors of the national economy in our country, as it gave the state a huge amount of fabric that was so necessary for it, which was constantly required not only for the production of clothing, but even used in the production of weapons.
In fairness it should be noted thatThey call not just one specific type of fabric, but several types of artificial fibers at once. In all cases, make them from acetylcellulose. The most common fiber is from acetylcellulose, as well as regular acetate fiber, produced from recycled cellulose acetate.
The hygroscopicity of such tissues does not exceed 3.5%.The fiber practically does not absorb moisture, does not swell and does not precipitate even after repeated cycles of soaking / drying. In comparison with natural fabrics, artificial ones are much less exposed to microorganisms, light and heat. In addition, the mole is completely indifferent to them. These fabrics are able to withstand heating up to 100 degrees Celsius without losing their qualities.
Things made from acetate fibers are quitepleasant in appearance, perfectly washable and dry quickly. In addition, when washing them you need to add much less detergent, as the dirt is easily washed out of the fibers of this type.
Note that weak acids and alkalis do not acton acetate fiber is as destructive as in the case of natural fabrics, but as a result it is saponified and loses most of its beneficial qualities. Concentrated inorganic acids destroy it immediately.
If you look at this tissue through a microscope, thenYou can see hundreds of longitudinal grooves on the surface of the fiber. Because of this, individual threads poorly interlock with each other, and the fabric as a whole is quite resilient and poorly crushed. Glitter makes them similar in appearance to natural silk, and the thickness of the individual fibers are quite similar to the thread, which is given by the larvae of mulberry silkworms. If the manufacturer is faced with the task of obtaining a fabric in which the threads will be firmly bonded to each other, then H-shaped transverse incisions are made on the surface of the fibers.
In addition to increased strength, this canvas is characterized by a very beautiful sparkling brilliance, and therefore it is often used for decoration purposes.
Unfortunately, not everything is so good:these types of artificial materials are very resistant to abrasion, very easily gain static electricity, poorly painted with standard paints that are commonly used in the textile industry. They should be ironed without raising the temperature of the iron above 115 °, since otherwise thermal deformation is possible.
Given the very high ability of acetatefiber to the accumulation of static charge, it is quite difficult to produce tissue from it. If you iron a little too far with the temperature of the iron, then on the surface of the fabric appear deep defects that can no longer be eliminated. The acetate fiber burns with a bright yellow color. Quite easily extinguished, after which it smolders for a long time, emitting a large amount of dense smoke with a specific smell into the surrounding air.
As you could understand, acetate fiberget from cellulose. Of course, it is preferable to use cotton, but with its lack or absence it is quite possible to use high-quality wood. After production and purification, it is treated with acetic anhydride. Sulfuric acid is used as a catalyst for the reaction, and acetic acid is added to dissolve the resulting cellulose acetate.
In the presence of a small amount of water fiberbegin to saponify, resulting in diacetylcellulose. A mixture of acetone and water (95: 1) is added to the substance obtained. All spinning mixture is ready. It is filtered, cleansing from an overabundance of coarse mechanical impurities, and then sent to the spinning machine. Obtaining acetate fiber occurs in air (dry method).
This method is also good for what is not required.use of any additional chemicals. Thick and crusty spinning mass is simply pressed through a die with many holes, after which it enters the vapor-air chamber at a temperature of about 87 degrees Celsius. Since the production of acetate fiber requires a huge amount of water and cellulose, there are many factories around Baikal.
High temperature is needed to have acetone.finally evaporated from the mixture. After that, the obtained threads are cooled, cover their surface with oil to prevent the formation of a static charge, and then wound on a bobbin. Up to 600 meters of filament is formed per minute. In the future, it requires almost no processing, except for the twisting only in the production of thicker fibers.
How is the coloring?In most cases, the dye is injected at the production stage, so that a thread of the desired shade is wound onto the bobbin. We have already said that acetate fiber is very poorly stained by standard means, and therefore at present 90% of fabrics are made from yarns made from spinning mixtures with desired qualities.
Nowadays, thousands of varieties have been created.special disperse paints. They allow you to get not just colored fabric, but real masterpieces that have an amazing iridescent color. This impression is due to the fact that the paint does not stick to the surface of the threads, as is the case with the same viscose canvas, but is part of the canvas itself.
Чаще всего в производстве применяются фильеры, having about 200 holes. If the resulting yarn is planned to be twisted into thick fibers or ropes, the mixture is passed through dies with corrugated and crimped walls. If we talk about staple acetate fibers, their production practically does not differ from the process described above.
The peculiarity is that the individual threads,leaving the forming unit, immediately collected into a bundle, which is immediately cut into pieces of the required length. In addition, staple fibers can be made in the form of ribbons, which are also further cut into pieces of the required length.
What are the main properties of acetate fiber?The thickness of the yarn produced in any case ranges from 11.1 tex X 25, to 16.7 tex X 25 (№ 90/25 - 60/25). If we compare it with viscose fibers of the same thickness, then the strength of acetate threads is slightly lower (by about 10-12%). But! If this fabric gets wet (yes, that is the hygroscopicity of 3.5%), then the strength parameters are reduced immediately by 40-45!
Tensile strength (tensile elongation) is equal toabout 27%, but the elastic elongation is much higher than that for repeatedly mentioned above viscose fabrics. It is because of this that “acetates” are very badly crushed, and the things from them look perfect for a long time.
Все вышесказанное может натолкнуть внимательного reader on the idea that the fabric of this type too many flaws. This statement is quite true for the recent past, but today, in its production, modifying additives are almost always used, which have no chemical effect on acetate fiber. The formula in this case is as follows: [C6H7O2 (OH) 3-x (OCOCH3) x].
In addition, today is increasingly useddirectional heat treatment of the spinning mass: the molecules begin to form more ordered structures. As a result, acetate fabric becomes much stronger, and is not so afraid of strong heat.
