Fibers of the past, present and future. Choosing a path is not an easy task. Chemical fibers and filaments Chemical fiber nonwovens
Usage: for the manufacture of inorganic fibers soluble in physiological fluids. Described are inorganic fibers whose vacuum preforms have a shrinkage of 3.5% or less when exposed at 1260° C. for 24 hours. increase in shrinkage above 3.5%. The preferred range of fibers has a shrinkage of 3.5% or less when exposed at 1500°C for 24 hours and may contain, wt.%: SrO 53.2-57.6, Al 2 O 3 30.4-40.1, SiO 2 5.06-10.1. The technical task of the invention is to reduce the shrinkage of the workpiece. 2 s. and 15 z.p. f-ly, 4 tab.
The invention relates to artificial fibers from inorganic oxide. The invention also relates to products made from such fibers. Inorganic fibrous materials are well known and widely used for many purposes (for example, as thermal or acoustic insulation in bulk form, in the form of mats or sheets, in the form of vacuum-formed forms, in the form of vacuum-formed cardboard and paper, and in the form of ropes, yarn or textile; as a reinforcing fiber for building materials; as a constituent of vehicle brake pads). In most of these applications, the properties for which inorganic fibrous materials are used require resistance to heat and often resistance to harsh chemical environments. Inorganic fibrous materials may be either glassy or crystalline. Asbestos is an inorganic fibrous material, one form of which has been implicated in respiratory disease. It is still unclear what the causal mechanism is that links some types of asbestos to disease, but some researchers believe that the mechanism is mechanical and related to particle size. Critical particle size asbestos can enter cells in the body and thus, through prolonged and repeated cell damage, adversely affect health. Whether this mechanism is true or not, regulators have mandated that any inorganic fibrous product that has a respiratory fraction be classified as unhealthy, whether or not there is any evidence to support such a classification. Unfortunately, for many of the applications for which inorganic fibers are used, there are no viable substitutes. Thus, there is a need for inorganic fibers that will present the lowest possible hazard (if any) and for which there are objective reasons to consider them safe. One line of research has been proposed, which is that inorganic fibers would be made that are sufficiently soluble in bodily fluids that their residence time in the human body is short; in this case, the damage would not have occurred, or at least would have been minimized. Since the risk of asbestos-related disease seems to depend very strongly on the duration of exposure to it, this idea seems reasonable. Asbestos is extremely insoluble. Since the interstitial fluid in nature is a saline (physiological) solution, the importance of dissolving the fibers in a saline solution has long been recognized. If the fibers are soluble in physiological saline, then, provided that the dissolved components are not toxic, the fibers should be safer than fibers that are insoluble. The shorter the residence time of a fiber in the body, the less damage it can cause. Such fibers are exemplified in the applicant's earlier International Patent Applications WO93/15028 and WO94/15883, which describe saline-soluble fibers used at temperatures of 1000°C and 1260°C, respectively. Another line of research suggests that hydrated fibers that lose their fibrous nature in body fluids may represent another route to "safe" fibers when the cause of damage is the shape and size of the fibers. This route is described in European Patent Applications N 0586797 and N 0585547, the purpose of which is to provide silica-free compositions and which describe two compositions of calcium aluminate (one containing 50/50 wt.% alumina/calcined lime, and the other containing 63 /30 wt.% alumina/calcined lime with the addition of 5% CaSO 4 and 2% other oxides). Such fibers hydrate easily, losing their fibrous nature. Asbestos does not hydrate and appears to retain its fibrous structure in body fluids effectively indefinitely. It has been found that strontium aluminate compositions do not appear to form fibers when meltblown products, while such compositions, including additives such as silica, do form fibers when meltblown. It appears that such fibers hydrate similarly to calcium aluminate fibers and further show potential for high temperature use. Vacuum-formed preforms (shapes) of some of these fibers show shrinkage of 3.5% or less when exposed to 1260° C. for 24 hours; some show shrinkage of 3.5% or less when exposed to 1400° C. for 24 hours and some even show shrinkage of 3.5% or less when exposed to 1500° C. for 24 hours. Such fibers provide hydrated high temperature fibers useful in the above products. Accordingly, this invention provides an inorganic fiber whose vacuum cast preform (shape) has a shrinkage of 3.5% or less when exposed at 1260 o C for 24 hours, a fiber containing SrO, Al 2 O 3 and a sufficient amount of fiber-forming additives for fiber formation, but not enough (not so much) to increase shrinkage above 3.5%. Preferably, the fiberizing additive contains SiO 2 and the constituents SrO, Al 2 O 3 and SiO 2 constitute at least 90 wt.% (more preferably at least 95 wt.%) of the fiber composition. The scope of the present invention is clearly defined in the appended claims with reference to the following description. In the following discussion, when a saline-soluble fiber is mentioned, it should be understood that it is a fiber having a total solubility of more than 10 ppm (ppm) in saline when measured by the method described below and, preferably, having higher solubility. The experimental results are described below with reference to tables 1, 2 and 3. Table 1 shows a number of compositions that were melted and blown by conventional methods. Those compositions indicated by "" did not fiberize to the desired extent, but did form a spherical powder. For each of these compositions, the analyzed composition is shown in wt. % (obtained by X-ray fluorescence analysis). If a number is given<0,05", это означает, что соответствующий компонент не мог быть обнаружен. Благодаря природе рентгеновских флуоресцентных измерений (которые чувствительны к окружающей среде) общее количество материала, обнаруживаемого этим анализом, может доходить до 100% или превышать 100%, и в данной патентной заявке (в том числе в описании, формуле изобретения и реферате) эти числа не были нормализованы до 100%. Однако для каждой композиции указывается общее количество анализируемого материала и можно видеть, что отклонение от 100% является небольшим. В столбце, названном "Относительный мас. процент", указаны мас. % SrO, Al 2 O 3 и SiO 2 по отношению к сумме этих компонентов. За исключением случаев, когда контекст дает иные указания, любые проценты, указанные в данной заявке, являются процентами, полученными рентгеновским флуоресцентным анализом, а не абсолютными процентами. Таблица 2 показывает (в том же порядке, что и в Таблице 1) данные усадки и растворимости для волокнообразующих композиций. Растворимость выражена как части на млн. В растворе, как измерено описанным ниже способом. Все указанные выше композиции и включая линию A Таблиц 1 и 2 включительно содержат 2,76 мас.% или менее SiO 2 . Можно видеть, что большинство этих композиций не образовывали волокна. Некоторые из этих волокон включают в себя Na 2 O в количествах 2,46 мас.% или более для содействия образованию волокна, но обнаруживают плохие характеристики усадки при температурах более 1000 o C (т.е. имеют усадку более 3,5% при измеренной температуре). Одно волокно (SA5 (2,5% K 2 O/SiO 2)), содержащее 1,96% K 2 O и 2,69% SiO 2 , имеет приемлемую усадку при 1260 o C. Таким образом, можно видеть, что "чистые" алюминаты стронция не образуют волокон, тогда как посредством добавления волокнообразующих добавок, например, SiO 2 и Na 2 O, могут быть образованы волокна. Характеристики усадки полученных волокон зависят от примененных добавок. Волокна, представленные ниже линии A и выше и включая линию В, имеют содержание SrO менее 35 мас.% и имеют плохие характеристики усадки. Волокна, показанные ниже линии В, имеют содержание SrO более 35 мас.% и, в случае измерения, обнаруживают приемлемую усадку при 1260 o C. Волокно линии С содержит 2,52 мас.% CaO и это, по-видимому, вредит характеристикам при 1400 o C. Волокна, представленные ниже линии D и выше и на линии E, имеют содержание Al 2 O 3 более 48,8 мас.%, что, по-видимому, неблагоприятно влияет на характеристики волокон при 1400 o C. Волокно ниже линии E имеет содержание SiO 2 14,9 мас.%, что, по-видимому, плохо для характеристик при 1400 o C (см. ниже для показателя при 1500 o C). Дальнейший ограниченный диапазон композиций (показанных жирным текстом в столбце 1400 o C) проявляет тенденцию к приемлемой усадке при 1400 o C. Эти композиции лежат ниже линии C и выше и на линии D Таблиц 1 и 2. Два волокна, указанных в этом диапазоне, которые не удовлетворяют требованию усадки 3,5%, могут быть просто неправильными результатами. Волокна, лежащие ниже линии C и выше линии D и на линии D, были отобраны по относительному мас.% SrO (как определено выше), и можно видеть, что композиции с относительным мас.% SrO, большим, чем 53,7%, и меньшим, чем 59,6%, имеют тенденцию к приемлемым усадкам при 1500 o C. Волокно в этой области, которое не имеет приемлемой усадки при 1500 o C, является волокном с высоким содержанием SiO 2 (12,2 мас.% SiO 2), что подтверждает неблагоприятное действие слишком большого содержания SiO 2 упомянутое выше. Два волокна (SA5a и SA5aII) обнаруживают приемлемую усадку при 1550 o C. Кроме того, можно видеть, что некоторые из этих волокон проявляют очень высокие растворимости и, таким образом, могут обеспечивать применимые трудно перерабатываемые (устойчивые) волокна, которые будут растворяться в жидкостях тела. Все волокна показали гидратацию при введении в водные жидкости. Действительно, они имели тенденцию к некоторой гидратации при образовании предварительных заготовок, которые были использованы для испытания усадки. После 24 часов испытания растворимости в жидкостях физиологического типа гидратация была очень явной. Гидратация имеет форму видимого растворения и переосаждения кристаллов на поверхности волокон, что приводит к потере их волокнистой природы. Для некоторых из композиций при изготовлении вакуумных предварительных заготовок для испытаний использовали диспергирующий и смачивающий агент (Troy EX 516-2 (Trade markof Troy Chemical Corporation)), который является смесью неионогенных поверхностно-активных веществ и химически модифицированных жирных кислот. Это было попыткой уменьшить время экспонирования с водой и, следовательно, степени гидратации. Из таблицы 3 можно видеть (Таблица 3 показывает тот же тип информации, что и Таблица 2), что композиции, в которых использовали диспергирующий агент (указанный как "troy"), имели тенденцию к более высокой усадке, чем идентичная композиция без диспергирующего агента. Предполагается, что это может быть обусловлено частичным гидратационным "смыканием" волокон вместе, так что любое отдельное волокно должно иметь усадку против растяжения поддерживающих волокон вдоль его длины: такое растяжение может приводить к утончению волокна скорее, чем к продольной усадке. В случае использования диспергирующего агента волокна свободны для усадки вдоль их длины. Далее подробно описаны способы измерения усадки и растворимости. Усадку измеряли посредством предложенного ISO стандарта ISO/TC33/SC2/N220 (эквивалент British Standard BS 1920, part 6.1986) с некоторыми модификациями с учетом малого размера образцов. Способ в кратком изложении содержит изготовление вакуумно отлитых предварительных заготовок, с использованием 75 г волокна в 500 куб. см 0,2% раствора крахмала, в приспособлении 120х65 мм. Платиновые штифты (приблизительно 0,5 мм в диаметре) помещали отдельно в 4 углах в виде прямоугольника 100х45 мм. Самые большие длины (L1 и L2) и диагонали (L3 и L4) измеряли с точностью 1 5 мкм, используя передвижной микроскоп. Образцы помещали в печь и доводили до температуры на 50 o C ниже температуры испытания при скорости 300 o C/час и при скорости 120 o C/час для последних 50 o C до температуры испытания и оставляли в течение 24 часов. Величины усадки даны в виде среднего из 4 измерений. Следует отметить, что хотя это стандартный способ измерения усадки волокна, он имеет присущую ему изменчивость, заключающуюся в том, что конечная плотность предварительной заготовки может меняться в зависимости от условий отливки. Кроме того, следует отметить, что волоконный материал будет обычно иметь более высокую усадку, чем предварительная заготовка, изготовленная из того же самого волокна. Поэтому цифру 3,5%, упоминаемую в данной заявке, следует толковать как более высокую усадку в конечном полотне из этого волокна. Растворимость измеряли согласно следующему способу. Волокно сначала нарезали с использованием сита 10 меш. и сферический порошок удаляли ручным просеиванием также через сито 10 меш. Устройство для испытания растворимости содержало вибрационную термостатную водяную баню и раствор для испытаний имел состав, приведенный в табл. 4. Вышеуказанные вещества разбавляли до 1 литра дистиллированной водой для образования солевого раствора, подобного физиологическому раствору. 0,500 г, "равных" 0,003 г нарезанного волокна, взвешивали в пластиковую пробирку центрифуги и добавляли 25 мл (см 3) указанного выше солевого раствора. Волокно и солевой раствор встряхивали тщательно и вводили в вибрационную термостатную водяную баню, поддерживаемую при температуре тела (37 o C 1 o C). Скорость вибратора устанавливали при 20 оборотов/мин. После 24 часов пробирку центрифуги удаляли, всплывающую жидкость декантировали и жидкость пропускали через фильтр (мембрана из фильтровальной бумаги из нитрата целлюлозы 0,45 микрон [типа WCN из Whatman Labsales Limited]) в прозрачный пластиковый флакон. Затем жидкость анализировали одним из двух способов. Первым используемым способом было атомное поглощение с применением машины Thermo Jarrell Ash Smith - Hiefje II. Условия работы были такие же, какие установлены в более ранних Международных Патентных заявках заявителя WO93,15028 и WO 94/15883. Для SrO условия работы были следующими:
WAVE LENGTH (nm) 460.7
BAND WIDTH, 0
CURRENT, (mA) 12
FLAME, lean fuel
Strontium was measured against a standard solution for atomic absorption (Aldrich 970 μm/ml). Three standards were prepared to which 0.1% KCl was added (Sr [ppm] 9.7, 3.9 and 1.9). Typically, 10- and 20-fold dilutions were prepared to measure the Sr level in the sample. SrO was then calculated as 1.183xSr. All stock solutions were stored in plastic bottles. In the second method used (which was shown to give results consistent with those of the first method), element concentrations were determined using inductively coupled plasma-atomic emission spectroscopy in accordance with a known method. The above has made it possible to discuss the shrinkage resistance of preforms exposed to 1260° C. for 24 hours. This is the maximum fiber usage temperature. In practice, fibers are characterized by a maximum continuous use temperature and a higher maximum exposure temperature. Typically in the industry, when selecting a fiber for use at a given temperature, a fiber is selected that has a higher continuous use temperature than the temperature nominally required for the intended use. This is to ensure that any accidental increase in temperature does not damage the fibers. A difference of 100-150 o C is quite common. Applicants have not yet determined what amount of other oxides or other impurities will affect the characteristics of the fibers described above, and the attached claims allow, in case the fiber-forming additive is SiO 2, up to 10 wt .% materials other than SrO, Al 2 O 3 and SiO 2 although this should not be considered as a limitation. Although the above description refers to meltblown fibers, this invention is not limited to blown, but also covers drawing and other methods (technologies) in which fibers are formed from the melt, and also includes fibers made by any other method.
CLAIM
1. Inorganic fiber containing SrO and Al 2 O 3 , characterized in that the vacuum fiber preform has a shrinkage of 3.5% or less when held at 1260 o C for 24 hours and the fiber has a composition of strontium aluminate, including SrO, Al 2 O 3 and a fiberizing additive sufficient to form a fiber, but not so large as to increase shrinkage above 3.5% and in the case where SiO 2 is present, the amount of SiO 2 is less than 14.9 wt.%. 2. An inorganic fiber according to claim 1, characterized in that the fiber-forming additive contains SiO 2 and the constituents SrO, Al 2 O 3 and SiO 2 constitute at least 90 wt.% of the composition of the fiber. 3. Inorganic fiber according to claim 2, characterized in that the constituents SrO, Al 2 O 3 and SiO 2 constitute at least 95 wt.% of the composition of the fiber. 4. An inorganic fiber according to any one of the preceding claims, characterized in that it contains 35% by weight or more of SrO. 5. Inorganic fiber according to any of the preceding claims, characterized in that it contains SrO 41.2 - 63.8 wt.% and Al 2 O 3 29.9 - 53.1 wt.%. 6. Inorganic fiber according to claim 5, characterized in that it contains more than 2.76 wt.% SiO 2 . 7. Inorganic fiber according to any one of the preceding claims, characterized in that the vacuum preform has a shrinkage of 3.5% or less when held at 1400°C for 24 hours. 8. Inorganic fiber according to claim 7, characterized in that the amount of Al 2 O 3 is 48.8 mass% or less. 9. Inorganic fiber according to any of the preceding claims, characterized in that the vacuum preform has a shrinkage of 3.5% or less when held at 1500 o C for 24 hours. 10. Inorganic fiber according to claim 9, characterized in that the mass% SrO relative to the total amount of SrO plus Al 2 O 3 plus SiO 2 is in the range from more than 53.7 wt.% to less than 59.6 wt.%. 11. Inorganic fiber according to claim 10, characterized in that it contains, wt. %:SrO - 53.2 - 57.6
Al 2 O 3 - 30.4 - 40.1
SiO 2 - 5.06 - 10.1
12. An inorganic fiber according to any one of the preceding claims, characterized in that it contains Na 2 O in an amount of less than 2.46% by weight. 13. An inorganic fiber according to any one of the preceding claims, characterized in that the vacuum preform has a shrinkage of 3.5% or less when held at 1550° C. for 24 hours. wt. %:
SrO - 53.2 - 54.9
Al 2 O 3 - 39.9 - 40.1
SiO 2 - 5.06 - 5.34
15. An inorganic fiber according to any one of the preceding claims, characterized in that it is a saline-soluble fiber. 16. An inorganic fiber according to any one of the preceding claims, characterized in that it is a hydrated, saline-soluble fiber. 17. Method for producing fibers from a melt, characterized in that the melt contains predominantly SrO and Al 2 O 3 , to which small amounts of SiO 2 are added to form fibers.
In addition to those already listed, there are fibers from natural inorganic compounds. They are divided into natural and chemical.
Asbestos, a fine-fibrous silicate mineral, belongs to natural inorganic fibers. Asbestos fibers are fire-resistant (the melting point of asbestos reaches 1500 ° C), alkali- and acid-resistant, non-heat-conducting.
The elementary fibers of asbestos are combined into technical fibers, which serve as the basis for threads used for technical purposes and in the development of fabrics for special clothing that can withstand high temperatures and open fire.
Chemical inorganic fibers are divided into glass fibers (silicon) and metal-containing.
Silicon fibers, or glass fibers, are made from molten glass in the form of elementary fibers with a diameter of 3-100 microns and very long lengths. In addition to them, staple fiberglass is produced with a diameter of 0.1-20 microns and a length of 10-500 mm. Fiberglass is non-combustible, chemically resistant, has electrical, heat and sound insulation properties. It is used for the manufacture of tapes, fabrics, nets, non-woven fabrics, fibrous canvases, cotton wool for technical needs in various sectors of the country's economy.
Metallic artificial fibers are produced in the form of threads by gradually drawing (drawing) a metal wire. This is how copper, steel, silver, gold threads are obtained. Aluminum filaments are made by cutting a flat aluminum strip (foil) into thin strips. Metal threads can be given different colors by applying colored varnishes to them. To give greater strength to metal threads, they are wrapped with threads of silk or cotton. When the threads are covered with a thin protective synthetic film, transparent or colored, combined metal threads are obtained - metlon, lurex, alunit.
The following types of metal threads are produced: rounded metal thread; flat thread in the form of a ribbon - flattened; twisted thread - tinsel; flattened, twisted with silk or cotton thread - stranded.
In addition to metallic ones, metallized threads are produced, which are narrow ribbons of films with a metallic coating. Unlike metallic threads, metallized threads are more elastic and fusible.
Metallic and metallized threads are used for the production of fabrics and knitwear for evening dresses, gold embroidery, as well as for decorative finishing of fabrics, knitwear and piece goods.
End of work -
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General information about fibers. Fiber classification. Main properties of fibers and their dimensional characteristics
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Lecture 1
Introduction. Fibrous materials 1. Aims and objectives of the course "Materials Science of Sewing Production". 2. General information about
cotton fiber
Cotton is the name given to the fibers that cover the seeds of the annual cotton plant. Cotton is a heat-loving plant that consumes a large amount of moisture. Grows in hot areas. Izv
Natural fibers of animal origin
The main substance that makes up natural fibers of animal origin (wool and silk) are animal proteins synthesized in nature - keratin and fibroin. Difference in molecular structure
Natural silk
Natural silk is called the thin continuous threads secreted by the glands of silkworm caterpillars during the curling of the cocoon before pupation. The main industrial value is domesticated mulberry silk.
B. Chemical fibers
The idea of creating chemical fibers found its embodiment at the end of the 19th century. thanks to the development of chemistry. The prototype of the process of obtaining chemical fibers was the formation of a silkworm thread
artificial fibers
Artificial fibers include fibers made from cellulose and its derivatives. These are viscose, triacetate, acetate fibers and their modifications. Viscose fiber is made from cellulose
Synthetic fibers
polyamide fibers. Capron fiber, which is used most widely, is obtained from coal and oil processing products. Under the microscope, polyamide fibers are
Types of textile threads
The basic element of a fabric or knitted fabric is a thread. According to the structure, textile threads are divided into yarn, complex threads and monofilaments. These threads are called primary
Basic spinning processes
The fibrous mass of natural fibers after collection and primary processing enters the spinning mill. Here, a continuous strong thread is produced from relatively short fibers - yarn. This p
Weaving
Fabric is a textile fabric formed by weaving two mutually perpendicular systems of threads on a loom. The process of fabric formation is called weaving.
Fabric finishing
The fabrics removed from the loom are called rough fabrics or rough. They contain various impurities and impurities, have an ugly appearance and are unsuitable for the manufacture of garments.
Cotton fabrics
During cleaning and preparation, cotton fabrics are subjected to acceptance and sorting, singeing, desizing, bleaching (bleaching), mercerization, and napping. Cleaning and
linen fabrics
Cleaning and preparation of linen fabrics is usually carried out in the same way as in cotton production, but more carefully, repeating the operations several times. This is due to the fact that linen
Woolen fabrics
Woolen fabrics are divided into combed (stone) and cloth. They differ from each other in appearance. Combed fabrics are thin, with a clear pattern of weaving. Cloth - more thick
Natural silk
Cleaning and preparation of natural silk is carried out in the following order: acceptance and sorting, singeing, boiling, bleaching, revitalization of bleached fabrics. When at
Chemical fiber fabrics
Fabrics made from artificial and synthetic fibers do not have natural impurities. They can contain mainly easily washed off substances, such as dressing, soap, mineral oil, etc.
Fibrous composition of fabrics
For the manufacture of clothing, fabrics made from natural (wool, silk, cotton, linen), artificial (viscose, polynose, acetate, copper-ammonia, etc.), synthetic (lavsa
Methods for determining the fibrous composition of tissues
Organoleptic is a method in which the fibrous composition of tissues is established using the sense organs - sight, smell, touch. Evaluate the appearance of the fabric, its touch, creasing
Weaving of fabrics
The location of the warp and weft threads relative to each other, their relationship determine the structure of the fabric. It should be emphasized that the structure of fabrics is influenced by: the type and structure of the warp and weft threads of the fabric
Fabric finishing
Finishing, which gives a marketable appearance to fabrics, affects its properties such as thickness, stiffness, drape, wrinkle, breathability, water resistance, sheen, shrinkage, fire resistance
Fabric Density
Density is an essential indicator of the structure of tissues. Weight, wear resistance, air permeability, heat-shielding properties, stiffness, and drapeability of fabrics depend on density. Each of
Phases of tissue structure
When weaving, the warp and weft threads mutually bend each other, as a result of which they are arranged in waves. the degree of bending of the warp and weft threads depends on their thickness and stiffness, type of p
Fabric surface structure
Depending on the structure of the front side, the fabrics are divided into smooth, pile, pile and felted. Smooth fabrics are those that have a clear weave pattern (coarse calico, chintz, satin). In the process of
Fabric properties
Plan: Geometric properties Mechanical properties Physical properties Technological properties Fabrics made from threads and yarns of various
Geometric Properties
These include the length of the fabric, its width, thickness and mass. The length of the fabric is determined by measuring it in the direction of the warp threads. When laying the fabric before cutting, the length of the piece
Mechanical properties
During the operation of clothing, as well as during the processing of fabrics, they are subjected to various mechanical stresses. Under these influences, tissues stretch, bend, and experience friction.
Physical properties
The physical properties of tissues are divided into hygienic, heat-shielding, optical and electrical. Hygienic is considered to be the properties of tissues that significantly affect whom
Fabric wear resistance
The wear resistance of fabrics is characterized by their ability to withstand destructive factors. In the process of using garments, they are affected by light, sun, moisture, stretching, compression, torsion.
Technological properties of fabrics
In the process of production and during the operation of clothing, such properties of fabrics are manifested, which must be taken into account when designing clothing. These properties significantly affect the technological
Gasket materials
5. Adhesive materials. 1. RANGE OF FABRICS According to the type of raw materials, the entire range of fabrics is divided into cotton, linen, wool and silk. The silk ones are
Adhesive materials
A semi-rigid interlining fabric with a dotted polyethylene coating is a cotton fabric (coarse calico or madapolam) coated on one side with high pressure polyethylene powder
The choice of materials for a garment
In the production of garments, a variety of materials are used: fabrics, knitted and non-woven fabrics, duplicated, film materials, natural and artificial fur, natural and artificial
Product quality
In the manufacture of clothing and other garments, fabrics, knitted and non-woven fabrics, film materials, artificial leather and fur are used. The totality of these materials is called an assortment
The quality of clothing materials
to make good clothes, you need to use high quality materials. What is quality? The quality of a product is understood as a combination of properties that characterize the degree of suitability
Grade of materials
All materials at the final stage of production are subject to control. At the same time, the quality level of the material is assessed and the grade of each piece is established. Grade refers to the gradation of product quality.
Fabric grade
Of great importance is the determination of the grade of fabrics. The grade of fabric is determined by a complex method for assessing the level of quality. At the same time, deviations of indicators of physical and mechanical properties from the norms,
Defects in the appearance of tissues
defect Type of defect Description Stage of production at which the defect arises Zaso
Article by G.E. Krichevsky, Doctor of Technical Sciences, Prof., Honored Worker of Science of the Russian Federation
Introduction
Currently, the most developed countries are moving into the 6th technological order, and developing countries are following them. This way of life (post-industrial society) is based on new, breakthrough technologies and, above all, nano-, bio-, info-, cognitive-, social technologies. This new paradigm of the development of civilization affects all areas of human practices, affects all technologies of previous modes. The latter do not disappear, but are significantly modified and modernized. But, most importantly, a qualitative change is the emergence of new technologies, their transition to a commercial level, the introduction of products of these technologies and modified traditional technologies into the daily life of a civilized person (medicine, transport of all kinds, construction, clothing, interior and home accessories, sports, army , means of communication, etc.).
Krichevsky G.E. - Professor, Doctor of Technical Sciences, Honored Worker of the Russian Federation, UNESCO expert, Academician of the RIA and MIA, Laureate of the MSR State Prize, member of the Nanotechnological Society of Russia.
This tectonic, technological shift did not bypass the field of fiber production, without which not only the production of textiles of all kinds, but many technical products of traditional and non-traditional applications (composites, medical implants, displays, etc.) is not possible.
Story
The history of fibers is the history of mankind, from primitive existence to modern post-industrial society. Life, culture, sports, science, technology, and medicine are inconceivable without clothes, home interiors, and technical textiles. But all types of textiles do not exist without fibers, which at the same time are only raw materials, but without which it is impossible to produce all types of textiles and other fiber-containing materials.
It is interesting to note that many thousands of years ago, starting from the end of the Paleolithic era (~ 10-12 thousand years BC) and until the end of the 18th century, man used exclusively, only natural (plant and animal) fibers . And only the first industrial revolution (the 2nd technological order - the middle of the 19th century) and, of course, advances in science and, above all, chemistry and chemical technologies, gave rise to the first generation of chemical fibers (hydrated cellulose - copper ammonia and viscose). From that moment to the present, the production of chemical fibers has developed extremely rapidly in quantitative terms (they overtook the production of natural fibers in 100 years) and in a number of positions in qualitative terms (a significant improvement in consumer properties). A brief history of fibers is presented in Table 1, from which it follows that the history of chemical fibers has gone through three stages, and the last one has not yet ended, and the third, young generation of chemical fibers is going through the stage of its formation. A SMALL TERMINOLOGICAL DIRECTION
There is a discrepancy in Russian (formerly Soviet) and international terms. According to Soviet, Russian terminology, fibers are divided into natural (vegetable, animal) and chemical (artificial and synthetic).
Let's ask ourselves the question "doesn't everything that surrounds us consist of chemical elements and substances?". And therefore they are chemical and, therefore, natural fibers are also chemical. The remarkable Soviet scientists who proposed this term “chemical” were, first of all, chemical technologists and put into this term the meaning that they are produced not by nature (biochemistry), but by man using chemical technologies. In the first place put, dominates in this term chemical technology.
International terminology refers to all artificial and synthetic fibers (polymers) as opposed to natural (natural) - miraculous, as made by human hands (man-made) - manmade fibers. This definition is more correct in my opinion. With the development of polymer chemistry and fiber production technologies, the terminology in this area is also developing, being refined, and becoming more complex. Terms such as polymeric and non-polymeric fibers, organic, inorganic, nanosized fibers, fibers filled with nanoparticles obtained using genetic engineering, etc. are used.
Alignment of terminology with advances in 3G fiber production will continue; this should be followed by both manufacturers and consumers of fibers in order to understand each other.
New, third generation of high-performance fibers (HEF)
Fibers of the third generation with such properties in the foreign literature are called HEV - high performance fibers (HPF - High Performance Fibers) and, along with new polymer fibers, include carbon, ceramic and new types of glass fibers.
The third, new generation of fibers began to form at the end of the 20th century and continues to develop into the 21st century, and is characterized by increased demands on their performance properties in traditional and new applications (aerospace, automotive, other modes of transport, medicine, sports, military , construction). These areas of application impose increased requirements on physical and mechanical properties, thermal, fire, bio, chemo, radiation resistance.
It is not possible to fully satisfy this set of requirements with an assortment of natural and chemical fibers of the 1st and 2nd generation. Advances in the field of chemistry and physics of polymers, solid state physics and the production of explosive explosives on this basis come to the rescue.
There are (synthesized) polymers with new chemical structure and physical structure obtained by new technologies. Establishing the relationship, cause-and-effect relationships between the chemistry, physics of fibers and their properties underlies the creation of 3rd generation fibers with predetermined properties and, above all, with high tensile strength, friction, bending, pressure, elasticity, thermal and fire resistance.
As can be seen from Table 1, which presents the history of fibers, the development of fibers occurs in such a way that the previous types of fibers do not disappear when new ones appear, but continue to be used, but their significance decreases, and new ones increase. This is the law of historical dialectics and the transition of products from one technological mode to another with a change in priorities. Until now, all natural fibers, chemical fibers of the 1st and 2nd generation are used, but new fibers of the 3rd generation are beginning to gain strength.
The production of synthetic fibers, fiber-forming polymers, like most modern organic low- and high-molecular substances, is based on oil and gas chemistry. The scheme of Figure 1 shows numerous products of primary and advanced processing of natural gas and oil up to fiber-forming polymers, fibers of the 2nd and 3rd generation.
As you can see, deep processing of oil and natural gas can produce plastics, films, fibers, drugs, dyes, and other substances.
In Soviet times, all this was produced, and the USSR occupied the leading (2–5) places in the world in the production of fibers, dyes, and plastics. Unfortunately, at present, all of Europe and China use Russian gas and oil, and many valuable products, including fibers, are produced from our raw materials.
Before the advent of chemical fibers, natural fibers (cotton) were used in a number of technical fields, having strength characteristics of 0.1–0.4 N/tex and an elastic modulus of 2–5 N/tex.
The first viscose and acetate fibers had a strength no higher than natural ones (0.2–0.4 N/tex), but by the 60s of the 20th century it was possible to raise their strength to 0.6 N/tex and the breaking elongation to 13% (due to the modernization of classical technology).
An interesting solution was found in the case of the Fortisan fiber: an elastomeric acetate fiber was saponified to hydrated cellulose and a strength of 0.6 N/tex and an elastic modulus of 16 N/tex were achieved. This type of fiber held out on the world market during the period 1939-1945.
High strength indicators are achieved not only due to the specific chemical structure of the polymer chains of fiber-forming polymers (aromatic polyamides, polybenzoxazoles, etc.), but also due to a special, ordered physical supramolecular structure (spinning from a liquid crystal state), due to a high molecular weight (high total energy of intermolecular bonds), as in the case of a new type of polyethylene fibers.
Since modern ideas about the mechanisms of destruction of polymeric materials and fibers, in particular, are reduced to the ratio of the strength of chemical bonds in the main chains of the polymer and intermolecular bonds between macromolecules (hydrogen, van der Waals, hydrophobic, ionic, etc.), the game to increase strength is on two fronts: high-strength single covalent bonds in the chain and high strength of total intermolecular bonds between macromolecules.
Polyamide and polyester fibers entered the world market (DuPont) in 1938 and are still present on it, occupying a vast niche in traditional textiles and in many areas of technology. Modern polyamide fibers have a strength of 0.5 N/tex and an elastic modulus of 2.5 N/tex, polyester fibers have similar strength and a higher elastic modulus of 10 N/tex.
It was impossible to realize a further increase in the strength characteristics of these fibers within the framework of existing technologies.
The synthesis and production of para-aramid fibers formed from the liquid crystal state with strength characteristics (strength 2 n/tex and elastic modulus 80 n/tex) was started by DuPont in the 60s of the 20th century.
In the last decades of the last century, carbon fibers with a strength of ~ 5 hPa (~ 3 N/tex) and an elastic modulus of 800 hPa (~ 400 N/tex), new generation glass fibers (strength ~ 4 hPa, 1.6 N/tex), elastic modulus 90 hPa (35 N/tex), ceramic fibers (strength ~3 hPa, 1 N/tex), elastic modulus 400 hPa (~100 N/tex).
Table 1 History of fibers
| *Item No.** | *Type of fiber** | *Usage time** | Technological order | Application area |
|---|---|---|---|---|
| I | NATURAL - NATURAL | |||
| 1a | Vegetable: cotton, linen, hemp, ramie, sisal, etc. | Mastered 10-12 thousand years ago; used to date | All pre-industrial technological and all industrial technological | Clothing, home, sports, medicine, army, limited in technology, etc. |
| 1b | Animals: wool, silk | |||
| II | CHEMICAL - MAN-MADE | |||
| 1 | 1st generation | |||
| 1a | Artificial: hydrated cellulose, copper ammonia, viscose | Late 19th – 1st half of 20th centuries, up to the present | 1st–6th technological modes | Clothing, home, sports, medicine, technology limited |
| 1b | Acetate | |||
| 2 | 2nd generation | |||
| 2a | Artificial: lyocell (hydrated cellulose) | 4th quarter of the 20th century to the present | 4th–6th technological modes | Clothing, medicine, etc. |
| 2b | Synthetic: polyamide, polyester, acrylic, polyvinyl chloride, polyvinyl alcohol, polypropylene | 30s - 70s of the 20th century to the present | Clothing, home, appliances, etc. | |
| 3 | 3rd generation | |||
| 3a | Synthetic: aromatic (para-, meta-) polyamides, high molecular weight polyethylene, polybenzoxazole, polybenzimidazole, carbon | 5th–6th technological modes | Technology, medicine | |
| 3b | Inorganic: new types of glass fibers, ceramic | late 20th - early 21st centuries | 6th technological mode | Technique |
| 3c | Nanosized and nanofilled fibers |
The 3rd generation of chemical fibers in foreign literature is called not only highly efficient (HEW), but also polyfunctional, smart. All these and other names, terms are not exact, controversial, in any case, not scientific. Because all existing both natural and chemical fibers, of course, to one degree or another, are both highly effective and multifunctional, and not stupid. Take at least the natural fibers of cotton, linen, wool, then not a single chemical fiber can surpass their high hygienic properties (they breathe, absorb perspiration, and flax is still biologically active). All fibers have not one, but several functions (polyfunctional). As you can see, the above terms are very arbitrary.
Physical and mechanical properties of VEV
Since the main areas of use of a new generation of fibers (cord for tires, composites for aircraft, rocket, automotive, construction) put forward high demands on the properties of fibers and, above all, on the physical and mechanical properties, we will dwell on these properties of VEV in more detail.
What physical and mechanical properties are important for new areas of fiber use: tensile strength, abrasion strength, compressive strength, twisting strength. At the same time, it is important for the fibers to withstand repeated (cyclic) deformation effects that are adequate to the operating conditions of products containing fibers. Figure 2 shows very clearly the difference in the requirements for physical and mechanical properties (tensile strength, modulus of elasticity), which impose three areas of use on fibers: traditional textiles, traditional technical textiles, and new areas of application in technology.
As can be seen, the demands on the strength properties of fibers from new and traditional applications are increasing significantly, and this trend will continue with the expansion of fiber applications. A striking example is the space elevator, which is already being talked about not only by science fiction writers, but also by engineers. And this project can only be realized using heavy-duty cables made of 3rd generation nanofibers and spider silk fibers (stronger than steel thread).
Figure 2
Explanations for Fig. 2: The modulus of elasticity and tensile strength are evaluated in the same units. The modulus of elasticity is a measure of the rigidity of a material, characterized by resistance to the development of elastic deformations. For fibers, it is defined as the initial linear relationship between load and elongation. Den (denier) - a unit of measurement of the linear density of a thread (fiber) = mass of 1000 meters in Tex - a unit (off-system) of measurement of the linear density of a fiber (thread) = g / km.
Table 2 shows the comparative characteristics of the physical and mechanical properties of various fibers, including high explosives.
Table 2. Comparative characteristics of the physical and mechanical properties of various fibers
It should be borne in mind that the physical and mechanical properties must be evaluated not by one indicator, but at least by the combination of two indicators, i.e. strength and elasticity under various types of deformation effects.
So, according to the data of Table 2, the steel thread wins in elasticity, but loses in specific density (very heavy). Considering all the indicators in the aggregate, you can choose the areas of use of fibers. So the cable for the space elevator should be not only super strong, but also light.
The fabric for a bulletproof vest should be light, resilient (drapeability) and able to dampen the kinetic energy of the bullet (depends on the burst energy, i.e. the ability to dissipate energy). Composite for racing cars must be impact-resistant and lightweight at the same time; seat belts should be made of high tenacity fibers with high resilience.
The requirements for the physical and mechanical characteristics of fibers, as a set, a combination of two or more indicators, can be continued. This set of properties and factors is formulated by the user based on the operating conditions of products containing fibers. Let us follow the change of generations of fibers on the example of a tire cord, the requirements for the physical and mechanical characteristics of which have been increasing all the time.
When the first cars appeared (1900), cotton yarn was used as a tire cord; with the advent of rayon viscose fibers in the period 1935–1955. they have completely replaced cotton. In turn, polyamide fibers (nylon of various types) replaced viscose fibers. But even classic polyamide fibers today do not meet the requirements of the automotive industry in terms of strength properties, especially in the case of tires for heavy transport, for aviation. Therefore, the polyamide cord has been replaced today by steel threads.
The maximum strength of commercial polyamide and polyester fibers reaches ~ 10 g/den (~ 1 GPa, ~ 1 N/tex). The combination of moderate high strength and resilience provides high breaking energy (breaking work) and high resistance to repeated shock deformations. However, these characteristics of polyamide and polyester fibers do not meet the requirements of certain new fiber applications.
For example, polyamide and polyester fibers, due to the high increase in stiffness at high strain rates, do not allow their use in anti-ballistic products.
At the same time, polyester fibers are very suitable for high-strength fishing gear (ropes, ropes, nets, etc.), since they are characterized by relatively high strength and hydrophobicity (not wetted by water); ropes made of polyester fibers are used on drilling rigs for operation at depths up to 1000–2000 m, where they are able to withstand a load of up to 1.5 tons.
The combination of high strength and high modulus of elasticity is provided by three groups of explosives: 1. based on aramids, high molecular weight polyethylene, other linear polymers, carbon fibers; 2. inorganic fibers (glass, ceramic); 3. based on thermosetting polymers that form a three-dimensional mesh structure.
VEV based on linear polymers
The first group of VEVs are based on linear (1D dimensional) polymers and the simplest of them is polyethylene.
As early as 1930, Staudinger proposed an ideal model of a supramolecular structure for materials made of linear polymers, providing a high modulus of elasticity along the main chains (11000 kg/mm2) and only 45 kg/mm2 between macromolecules bound by van der Waals forces.
Figure 3. Ideal physical structure of a linear polymer according to Staudinger.
As can be seen (Fig. 3), the strength of the structure is determined by the elongation and high orientation of macromolecule chains along the fiber axis.
The technology (state of the spinning solution and melt, drawing conditions) for the production of fibers must be designed in such a way that folds of macromolecules do not form. Fiber-forming polymers with a certain chemical structure of macromolecules already in solution form elongated, oriented structures combined into blocks (liquid crystals). When fibers are formed from such a state, reinforced by a high degree of drawing, a structure is formed that is close to ideal according to Staudinger (Fig. 3). This technology was first implemented by DuPont (USA) in the production of Kevlar fibers based on polyparaaramid and polyphenylene terephthalamide. In these high-strength fibers, aromatic rings are linked by amide groups.
The presence of cycles in the chain provides elasticity, and amide groups form intermolecular hydrogen bonds responsible for tensile strength.
According to a similar technology (liquid-crystal state in solution, a high degree of elongation during molding, VEVs are produced from various polymers by various companies, in different countries under different trade names: Technora (Taijin, Japan), Vectran (Gelanese, USA), Tverlana, Terlon (USSR, Russia), Mogelan-HSt and others.
Carbon fibers and graphene layers
There are no large 2D-dimensional molecules in nature. Monofunctional molecules in reactions give molecules of small sizes; bifunctional give linear (1D-dimensional) polymers; three- and more-functional reagents form 3D-dimensional, mesh cross-linked structures (thermoplastics). Only the specific geometry of the direction of bonds capable of being formed by carbon atoms leads to layered molecules. Graphene, a hexonal, planar network of carbon atoms, is the first example of such a structure.
Carbon fibers are usually obtained by high-temperature processing (cracking) of organic fibers (cellulose, polyacrylonitrile) under tension. Strong, elastic fibers are obtained, in which one-dimensional layers are oriented parallel to the fiber axis.
3D mesh structures
Polymers with a 3D network structure are commonly referred to as thermoplastics because they are formed in thermocatalytic condensation reactions of polyfunctional monomers.
3D thermoplastics can be obtained in the form of fibers. Possessing heat resistance, such fibers do not differ in high strength. Examples of such fibers are fibers based on melamine-formaldehyde and phenol-aldehyde polymers*.
Inorganic 3D-dimensional mesh structures (glass and ceramic) and fibers based on them, as well as based on metal oxides and carbides, are characterized by high strength, elasticity, thermal and fire resistance.
- The main polymer of the wool fiber - keratin - is also a reticulated rare cross-linked natural polymer. Differs in unique elastic properties (resistance to compression). The cross-linking of a linear cellulose polymer with rare cross-links gives the fiber and fabrics from it a resistance to crushing, which cellulose fibers do not initially possess. However, this reduces (~15%) the tensile strength and abrasion.
Figures 4–10 show the comparative physical and mechanical characteristics of the EEW.
Table 3 shows the main performance characteristics of natural and chemical fibers.
Figure 4. Load-elongation curves for conventional fibers and ERW.
Figure 5. Relationship between specific strength and modulus of elasticity of EEV.
Figure 6. Dependence of strength mass on strength/volume for HEV.
Figure 8. Load-tensile curves for a composite based on HEV in an epoxy matrix.
Figure 9. Breaking length in kilometers for EW.
Figure 10. VEV. Main areas of use.
Table 3. Main performance characteristics of natural and man-made fibers (Hearle).
| № | fiber type | Density g/cm3 | Humidity, at 65% humidity | Melting point, ° С | Strength, N/tex | Modulus of elasticity, N/tex | Break work, J/g | Breaking elongation, % |
| 1 | Cotton | 1,52 | 7 | 185* | 0,2–0,45 | 4–7,5 | 5–15 | 6–7 |
| 2 | Linen | 1,52 | 7 | 185* | 0,54 | 18 | 8 | 3 |
| 3 | Wool | 1,31 | 15 | 100**/300* | 0,1–0,15 | 2–3 | 25–40 | 30–40 |
| 4 | Natural silk | 1,34 | 10 | 175* | 0,38 | 7,5 | 60 | 23 |
| 5 | Viscose | 1,49 | 13 | 185* | 0,2–0,4 | 5–13 | 10–30 | 7–30 |
| 6 | Polyamide | 1,14 | 4 | 260*** | 0,35–0,8 | 1,–5 | 60–100 | 12–25 |
| 7 | Polyester | 1,93 | 0,4 | 258 | 0,45–0,8 | 7,–13 | 20–120 | 9–13 |
| 8 | Polypropylene-new | 0,91 | 0 | 165 | 0,6 | 6 | 70 | 17 |
| 9 | n-aramid | 1,44 | 5 | 550* | 1,7–2,3 | 50–115 | 10–40 | 1,5–4,5 |
| 10 | m-aramid | 1,46 | 5 | 415* | 0,49 | 7,5 | 85 | 35 |
| 11 | Vectran | 1,4 | < 0,1 | 330 | 2–2,5 | 45–60 | 15 | 3,5 |
| 12 | HMPE | 0,97 | 0 | 150 | 2,5–3,7 | 75–120 | 45–70 | 2,9–3,8 |
| 13 | PBO | 1,56 | 0 | 650* | 3,8–4,8 | 180 | 30–90 | 1,5–3,7 |
| 14 | Carbon | 1,8–2,1 | 0 | >2500 | 0,4–3,9 | 20–370 | 4–70 | 0,2–2,1 |
| 15 | glass | 2,5 | 0 | 1000–12000**** | 1–2,5 | 50–60 | 10–70 | 1,8–5,4 |
continuation of the table. 3
| 16 | Ceramic | 2,4–4,1 | 0 | >1000 | 0,3–0,95 | 55–100 | 0,5–9 | 0,3–1,5 |
| 17 | Chemo-resistant | 1,3–1,6 | 0–0,5 | 170–375***** | 0–0,65 | 0,5–5 | 15–80 | 15–35 |
| 18 | heat resistant | 1,25–1,45 | 5–15 | 200–500**** | 0,1–1,3 | 2,5–9,5 | 10–45 | 8–50 |
- - destruction; ** - softening; *** - for nylon 66, nylon 6 - 216°; **** - liquefaction;
***** - temperature fork
Economics of VEV
In the 50s of the last century, polyamide and polyester fibers were literally a "miracle" for the consumer, who was hungry for an abundance of textile products with new properties. After the industrial development of fibers of this type by the largest chemical concern in the world, DuPont (USA), all the leading chemical firms in the developed capitalist countries rushed after them and began to produce such fibers under different names.
The chemical industry of the USSR did not stand aside either, which took a reference point to one type of polyamide fiber - capron based on polycaproamide. This technology was exported from Germany in 1945 for reparations. Prominent Soviet polymer scientist Professor Zakhar Alexandrovich Rogovin took part in the dismantling of the German factories that produced this fiber under the name Perlon. Together with a group of Soviet scientists and engineers, he set up the production of capron at a number of factories in various cities of the USSR (Klin, Kalinin (Tver)).
Polyester fibers based on polyethylene terephthalate were produced on a large scale in the USSR under the brand name Lavsan - an abbreviation for the laboratory of high-modulus compounds of the Academy of Sciences. These two fibers have become the main multi-tonnage fibers and still remain so in the world. These fibers are very widely used alone or mixed with other fibers both in the production of clothing, home textiles and in the technical sector.
The global balance of fiber production and consumption in 2010 is shown in Figure 11.
Figure 11.
Figure 12.
Polyester. 2000 - 19.1 million tons;
2010 - 35 million tons;
2020 - 53.4 million tons.
Cotton. 2000 - 20 million tons;
2010 - 25 million tons;
2020 - 28 million tons.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Before moving on to the economics of the VEV, let's say how the pricing and investment policy for the production of polyamide and polyester fibers was built. At the beginning (30-40s of the 20th century) of entering the market, polyamide and polyester fibers were several times more expensive than natural fibers of cotton and even wool. This is hard to believe now, when the picture is the opposite and corresponds to the real ratio of the cost of production of these fibers. But it was absolutely the right pricing policy, typical for the start of a potentially mass product entering the market. This pricing policy allows significant revenues to be directed to subsequent research on the development and improvement of the production of new types of fibers, including EVW. Currently, polyamide and polyester fibers are produced by many companies in many countries on a large scale. Such competition, large circulations of these fibers have led to prices quite close to the cost.
A different, more complicated situation is in the case of the EW economy. DuPont, starting research in the field of aromatic polyamides, which led to the creation of Kevlar fibers from them (based on n-polyaramid), initially focused them on the tire cord market.
The appearance of heavy and high-speed vehicles, heavy aircraft required a high-strength cord; not only cotton and viscose fibers did not meet these requirements, but also much stronger polyamide and polyester fibers.
Increasing the strength of the cord proportionally increased the service life of the tires ("mileage") and saved the consumption of fibers for the production of cord.
Kevlar and other high strength VEVs are used for specialty tires (racing cars, heavy trailers). Due to the specifics of the market for their consumption, VEVs are produced to order in small batches, by a small number of manufacturers using a much more complex technology (multi-stage synthesis, expensive raw materials, complex molding technology, high draw ratio, exotic solvents, low molding speeds) and, of course, at high prices . But those areas of technology in which VEVs are used (aircraft, rocket science) can afford to consume fibers at high prices, which are unacceptable in the case of the production of clothing and home textiles.
The production of the most used explosives reaches ~ 10 thousand tons per year, highly specialized 100 tons per year or less (Fig. 19).
Figure 19.
An exception is the VEV based on high molecular weight polyethylene, since both the raw material itself (ethylene) and the polymer are produced using a well-known relatively simple technology. It is only necessary at the polymerization stage to ensure the formation of a polymer with a high molecular weight, which determines the excellent physical and mechanical characteristics of this type of fiber. Prices on the world market for EVs are high, but they vary greatly and depend on many factors (fiber fineness, strength, yarn type, etc.) on market conditions (raw materials). Therefore, in different sources we find large fluctuations in prices (Table 4). So for carbon fibers, the price ranges from 18 DS/kg to 10,000 DS/kg.
Predicting the dynamics of changes in prices for EVs is much more difficult than for large-tonnage traditional fibers (tens of million tons are produced per year), and investing in large-tonnage production of EVs is a very risky business. The most capacious market for EVs is the production and consumption of a new generation of composite materials, catalyzing work to improve the technology of EV production.
So far, no new plants are being built for the production of VEVs, but they are produced at existing plants on special pilot plants and lines.
Of course, the army, sports, medicine (implants), construction, and, of course, aviation and aeronautics are real and potential users of EW. Thus, a 100 kg reduction in aircraft weight due to a new generation of lightweight and durable composites reduces annual fuel costs by 20,000 DS per aircraft.
For all innovations there is an investment risk, but without risk there is no success. It is only in a student project that a business plan can be accurately calculated. Paper will endure everything.
The founder of the world-famous automobile company Honda, Soichiro Honda, said well about this: “Remember, success can be achieved through repeated trial and error. Actual success is the result of 1% of your hard work and 99% of failure.” Of course, this is hyperbole, but not far from the truth.
Table 4 Prices for various EEVs in comparison with polyester technical fibers
| №№ | Type of fiber | Price in DS/kg |
| 1 | 2 | 3 |
| 1. | Polyester | 3 |
| 2. | High modulus polymer fibers | |
| n-aramid | 25 | |
| m-aramid | 20 | |
| high molecular weight polyethylene | 25 | |
| Vectran | 47 | |
| Zylon (Polybenzoxazole PBO) | 130 | |
| Tensylon (SSPE) | 22–76 | |
| 3. | carbon fibers | |
| based on PAN fibers | 14–17 | |
| based on petroleum pitch (conventional) | 15 | |
| based on petroleum pitch (high modulus) | 2200 | |
| based on oxidized acrylic fibers | 10 |
continued table 4
| 1 | 2 | 3 |
| 4. | Glass fibers | |
| E-type | 3 | |
| S-2-type | 15 | |
| Ceramic | ||
| SiC species: Nicolan NI, Tyrinno Lox-M, ZM | 1000–1100 | |
| stochometric type | 5000–10000 | |
| Alumina-type | 200–1000 | |
| boron-type | 1070 | |
| 5. | Heat and chemical resistant | |
| PEEK | 100–200 | |
| Thermoplastics Basofil | 16 | |
| Thermoplastics Kynol | 15–18 | |
| PBI | 180 | |
| PTFE | 50 |
The production of modern types of fibers (polyester, polyamide, acrylic, polypropylene and, of course, VEV) in the Russian Federation is extremely justified in terms of the huge reserves of natural raw materials (oil, gas) for the production of fibers and their great need for the modernization of a significant number of industries (oil -, gas processing, textile, shipbuilding, automotive). Half of the world (excluding the USA, Canada, Latin America) uses our raw materials to do all this and sells it to us with a high added value. The production of a new generation of chemical fibers can play the role of a locomotive for the development of the domestic industry, becoming one of the important factors in the national security of the Russian Federation.
References:
- G.E. Krichevsky. Nano-, bio-, chemical technologies and production of a new generation of fibers, textiles and clothing. M., Izvestiya publishing house, 2011, 528 p.
- High Performance Fibers. Hearle J.W.S. (ed.). Woodhead Publishing Ltd, 2010, p.329.
military textiles. Edited by E Wilusz, US Army Natick Soldier Center, USA. Woodhead Publishing Series in Textiles. 2008, 362 rubles
- PCI fibers. Fibers Economics in an Ever Changing World Outlook Conference. www.usifi.com/…look_2011pdf
Abbreviation in the name of the fibers
| English | Russian |
| Carbone HS | carbon |
| HPPE | high-strength polyethylene |
| Aramid | aramid |
| E-S-Glass | glass |
| Steel | steel |
| Polyamide | polyamide |
| PBO | polybenosexazole |
| polypropylene | polypropylene |
| Polyester | polyester |
| Ceramic | ceramic |
| Boron | boron based |
| Kevlar 49,29,149 | aramid |
| Nomex | m-aramid |
| Lycra | elastomeric polyurethane |
| Teflon | polytetrafluoroethylene |
| Aluminum | based on aluminum compounds |
| Para-aramid | p-aramid |
| m-aramid | m-aramid |
| Dyneema | high molecular weight polyethylene HMPE |
| Coton | cotton |
| Acrylic | acrylic |
| Wool | wool |
| Nylon | polyamide |
| Cellulosic | artificial cellulose |
| PP | polypropylene |
| PPS | polyphenylene sulfide |
| PTFE | polytetrafluoroethylene |
| Cermel | polyaramidimide |
| PEEK | polyetherketone |
| PBI | polybenzimidazole |
| P-84 | polyarimid |
| Vectran | aromatic polyester |
Related materials
- "Other materials of the Author on our website":
The 19th century was marked by important discoveries in science and technology. A sharp technical boom affected almost all areas of production, many processes were automated and moved to a qualitatively new level. The technical revolution did not bypass the textile industry either - in 1890, a fiber made using chemical reactions was first obtained in France. The history of chemical fibers began with this event.
Types, classification and properties of chemical fibers
According to the classification, all fibers are divided into two main groups: organic and inorganic. Organic fibers include artificial and synthetic fibers. The difference between them is that artificial ones are created from natural materials (polymers), but with the help of chemical reactions. Synthetic fibers use synthetic polymers as raw materials, while the processes for obtaining fabrics are not fundamentally different. Inorganic fibers include a group of mineral fibers that are obtained from inorganic raw materials.
As a raw material for artificial fibers, hydrated cellulose, cellulose acetate and protein polymers are used, for synthetic fibers - carbochain and heterochain polymers.
Due to the fact that chemical processes are used in the production of chemical fibers, the properties of the fibers, primarily mechanical, can be changed using different parameters of the production process.
The main distinguishing properties of chemical fibers, in comparison with natural ones, are:
- high strength;
- the ability to stretch;
- tensile strength and long-term loads of different strengths;
- resistance to light, moisture, bacteria;
- crease resistance.
Some special types are resistant to high temperatures and aggressive environments.
GOST chemical threads
According to the All-Russian GOST, the classification of chemical fibers is quite complicated.
Artificial fibers and threads, according to GOST, are divided into:
- artificial fibers;
- artificial threads for cord fabric;
- artificial threads for technical products;
- technical threads for twine;
- artificial textile threads.
Synthetic fibers and threads, in turn, consist of the following groups: synthetic fibers, synthetic threads for cord fabric, for technical products, film and textile synthetic threads.
Each group includes one or more subspecies. Each subspecies has its own code in the catalog.
Technology of obtaining, production of chemical fibers
The production of chemical fibers has great advantages over natural fibers:
- firstly, their production does not depend on the season;
- secondly, the production process itself, although quite complicated, is much less laborious;
- thirdly, it is an opportunity to obtain a fiber with pre-set parameters.
From a technological point of view, these processes are complex and always consist of several stages. First, the raw material is obtained, then it is converted into a special spinning solution, then the fibers are formed and finished.
Various techniques are used to form fibers:
- use of wet, dry or dry-wet mortar;
- application of metal foil cutting;
- drawing from a melt or dispersion;
- drawing;
- flattening;
- gel molding.
Application of chemical fibers
Chemical fibers have a very wide application in many industries. Their main advantage is relatively low cost and long service life. Fabrics made from chemical fibers are actively used for tailoring special clothes, in the automotive industry - for strengthening tires. In the technique of various kinds, non-woven materials made of synthetic or mineral fibers are more often used.
Textile chemical fibers
Gaseous products of oil and coal refining are used as raw materials for the production of textile fibers of chemical origin (in particular, for the production of synthetic fibers). Thus, fibers are synthesized that differ in composition, properties and combustion method.
Among the most popular:
- polyester fibers (lavsan, krimplen);
- polyamide fibers (nylon, nylon);
- polyacrylonitrile fibers (nitron, acrylic);
- elastane fiber (lycra, dorlastan).
Among the artificial fibers, the most common are viscose and acetate. Viscose fibers are obtained from cellulose - mainly spruce. Through chemical processes, this fiber can be given a visual resemblance to natural silk, wool or cotton. Acetate fiber is made from waste from cotton production, so they absorb moisture well.
Chemical fiber nonwovens
Nonwoven materials can be obtained from both natural and chemical fibers. Often non-woven materials are produced from recycled materials and waste from other industries.
The fibrous base, prepared by mechanical, aerodynamic, hydraulic, electrostatic or fiber-forming methods, is fastened.
The main stage in the production of nonwoven materials is the stage of bonding the fibrous base, obtained by one of the following methods:
- Chemical or adhesive (adhesive)- the formed web is impregnated, coated or sprinkled with a binder component in the form of an aqueous solution, the application of which can be continuous or fragmented.
- Thermal- this method uses the thermoplastic properties of some synthetic fibers. Sometimes the fibers that make up the nonwoven material are used, but in most cases a small amount of fibers with a low melting point (bicomponent) is deliberately added to the nonwoven material at the spinning stage.
Chemical fiber industry facilities
Since the chemical production covers several industries, all chemical industry facilities are divided into 5 classes depending on the raw materials and application:
- organic matter;
- inorganic substances;
- organic synthesis materials;
- pure substances and chemicals;
- pharmaceutical and medical group.
According to the type of purpose, chemical fiber industry facilities are divided into main, general factory and auxiliary.
