At all times, the textile industry was one of the most important sectors of the economy in our country, as the government gave a huge amount because it needed tissue that is constantly required not only for clothing, but even used in the manufacture of weapons.
So almost from the first days of the Soviet Union before the chemists was tasked with producing artificial tissues, as natural materials sorely lacking.The result was a cellulose acetate fiber.
What is it?
fairness it should be noted that the so-called not any one particular type of tissue, but several types of synthetic fibers.In all cases, make them CA.The most common triacetyl cellulose fiber, as well as the usual acetate fiber, produced from recycled cellulose acetate.
Important quality synthetic fibers
hygroscopicity such tissues does not exceed 3.5%.The fiber is almost does not absorb moisture, does not swell and does not rain, even after multiple cycles of soaking / drying.In comparison with natural fabrics, artificial much less exposed to microorganisms, light, and heat.In addition, they were completely indifferent mole.These fabrics are capable of without losing their properties to withstand heat up to 100 degrees Celsius.
Things made of acetate fibers, very pleasant to the sight, perfectly erased and quickly dry out.In addition, when washing is much less need to add detergent, as the dirt is easily washed away from the fibers of this type.
Note that the weak acids and bases do not affect acetate fiber so detrimental, as in the case with natural fabrics, but as a result it is saponified and lose much of their useful qualities.Concentrated inorganic acids also destroy it immediately.
microscopic structure of the fiber
If you look at this tissue under a microscope, you can see hundreds of longitudinal grooves on the surface of the fiber.Because of this, individual yarns badly adhere among themselves, and the fabric generally sufficiently resilient and badly wrinkled.Glitter they have in common in appearance with natural silk, and on the thickness of the individual fibers are quite similar to the thread that issued the larvae of silkworms.If the task before producer producing fabrics in which filaments are firmly bonded to each other, on the surface of the fibers are made of H-shaped cross-cuts.
Besides high strength, such a fabric is characterized by a very nice sparkling brilliance, but because it is often used in decoration purposes.
Disadvantages acetate fabrics
Unfortunately, all is not well: these kinds of artificial materials resist abrasion is very bad, very easy to gain static electricity, badly painted with standard colors that are commonly used in the textile industry.They should be ironed without raising the temperature of the iron over 115 °, since otherwise possible thermal deformation.
Other negative qualities
Given the very high capacity of cellulose acetate fibers to the accumulation of static charge from it rather difficult to produce cloth.When ironing a little too far with the temperature of the iron, on the surface there are deep tissue defects that it is already impossible to eliminate.Lights acetate fiber bright yellow.Quite easily quenched, and then a long smoldering, highlighting the surrounding air a large amount of dense smoke and odor.
production
As you can understand, acetate fiber is produced from cellulose.Of course, it is preferable to use cotton, but it is low or it is possible to use high-quality wood.After development and cleaning it is treated with acetic anhydride.As the reaction catalyst used is sulfuric acid, and to dissolve the resulting acetic acid is added to cellulose acetate.
In the presence of small amounts of water begin to saponify fibers, resulting in a cellulose diacetate.To the resulting substance is added to a mixture of acetone and water (95: 1).All spinning the mixture is ready.It is filtered, cleaned of excess coarse solids, and then sent to a spinning machine.Preparation of acetate fibers occurs in the air (the dry method).
This method is also that it does not require the use of any additional chemicals.Thick and viscous spinning mass is extruded through a die simply with a plurality of openings, and then enters the air-steam chamber at a temperature of about 87 degrees Celsius.Since the production of cellulose acetate fibers requires huge amounts of water and cellulose, many plants have about lake.
Some information about the color
High temperature is needed to completely evaporate the acetone from the mixture.Thereafter, the yarn is cooled, its surface is coated with oil to prevent the formation of static charges, and then wound onto a bobbin.One minute is formed up to 600 meters of thread.Further it requires practically no machining except only twisted in the production of thicker fibers.
How coloring?In most cases, the dye is introduced at the production stage, so that a bobbin thread is wound has a desired hue.We have already said that the acetate fiber very badly stained by standard means, so now 90% of the fabrics are made from yarns made of spinning mixtures with specified properties.
Nowadays, created thousands of varieties of special disperse dyes.They allow you to get not just a colored cloth, and real masterpieces with amazing iridescent color.The impression created by the fact that the paint does not stick to the surface of the filaments, as is the case with the same viscose cloth, and is part of the web.
If necessary, use white colors, resulting in a virtually flawless snow-white fabric dyeing.Since acetate fiber is very resistant to UV rays and very easy to wash, the durability of the canvas many times greater than the rate for cotton or other natural fabrics.
How is forming
most commonly used in the manufacture of a die having 200 holes.If the resulting string is scheduled to roll into thick fibers or ropes, and the mixture is passed through a die with corrugated walls and crimped.Speaking of the staple fibers, acetate, their production does not differ from that described by us above process.
feature consists in that the individual filaments issuing from the spinning device immediately collected into a bundle which is immediately cut into pieces of desired length.In addition, staple fibers can be made in the form of ribbons, which are then also cut into pieces of desired length.
basic properties of the fibers
What are the main properties of cellulose acetate fibers?The thickness of the yarn produced in any case, is between 11.1 X 25 tex, tex to 16.7 X 25 (№ 90 / 25- 60/25).When compared with the viscose fibers of the same thickness, then the acetate yarns strength is somewhat lower (by about 10-12%).But!If the fabric gets wet (yes, the same hygroscopicity of 3.5%), the strength values are reduced immediately by 40-45!
tensile strength (elongation at break) is about 27%, but much higher than the elastic elongation of such repeatedly for the above-mentioned viscose fabrics.It is because of this "acetates" very badly rumpled and things from them for a long time, it looks perfect.
Upgraded Version
All of this can touch up the attentive reader to believe that this type of fabric too many shortcomings.This statement is quite true for the recent past, but today, when its production is almost always used by builders that do not have any chemical effect on the cellulose acetate fiber.The formula in this case is as follows: [C6H7O2 (OH) 3-x (OCOCH3) x].
Also today are increasingly using targeted heat treatment of the spinning mass of the molecules begin to form a more ordered structure.As a result, the acetate fabric becomes much stronger and not so afraid of the intense heat.
To date, such as characterizing fiber "Alon" producing the type of staple fabric.It is very strong and elastic, has high durability and beautiful appearance.Empirically it has been found that a small amount of aluminum pyrophosphate added to the spinning mass produces acetate fiber, the use of which may in any area where there is a danger of fire (curtains for the theater, for example).
