CC BY
17
Razhapov Odil Olimovich, doctoral student, Zhumaniyazov Kadam Zhumaniyazovich,
professor, Gafurov Kabul Gafurovich, professor,
Matismailov Saipilla Lolashbaevich, assistant professor, Tashkent Institute of Textile and Light Industry E-mail: Odil_2005@rambler.ru
DETERMINATION OF OPTIMAL COMPOSITION OF COTTON-NITRONIC YARN
Abstract: The article presents the results of tests of cotton-nitron yarn with different components and recommended the optimal composition of the mixture, as well as examined the pre-breaking characteristics of cotton-nitron yarn and determined the patterns of their variation.
Keywords: cotton-nitrone yarn, blend, breaking load, tensile elongation.
One of the important problems facing in the Republic The experiment for the production of cotton yarn with
is the rational use of raw materials. First of all, this problem various components (from 10% to 90% of nitron fiber) was should be solved in the most material-intensive sectors of the carried out on the laboratory installation "Shirley". The labo-national economy, to which the textile industry belongs. ratory unit includes: carding machine, banding machine, ring
One of the most promising areas for the development of spinning machine. the textile and light industry is the production of yarn, fabric Applied cotton fibers 5th type I class, variety S4727.
and knitted fabrics made from mixtures of chemical fibers 9 variants of the mixture were studied and analyzed in the
with natural fibers. ratio of 10, 20, 30, 40, 50, 60, 70, 80, 90% with the content of
Synthetic fiber nitrone is mixed with fiber wool and cotton nitron fiber. To improve the technological properties of the to impart valuable properties that expand the use of mixed yarn. fiber and reduce static charges, the nitrone was pretreated with The purpose of this work is to substantiate the optimal ratio a concentrate of antistatic "triamon" and yarn samples were of fiber nitron to cotton by conducting a search experiment. obtained from the mixture.
For carrying out experimental studies, were used nitron The physical and mechanical properties of the yarn were
fiber with physical and mechanical properties approximated determined on the instruments installed in the certification to cotton fiber. center "Centexuz". The test results are shown in Table 1.
Table 1.- Physicomechanical properties of blended yarn
% cotton/ nitron Linear density of yarn T, tex Twist, K, t/m Relative explosive load R, sN/tex Absolute breaking load P, sN Break time t, s Square unevenness on breaking load, C2 {P}
90/10 17,99 834,66 12,79 231,03 5,38 16,23
80/20 16,62 847,27 11,83 192,55 3,94 12,91
70/30 19,72 852,83 9,23 182,61 3,99 18,54
60/40 18,06 888,05 10,08 182,70 4,36 16,38
50/50 19,38 864,72 10,20 198,19 4,58 15,61
40/60 17,54 858,22 9,73 171,01 4,46 17,44
30/70 18,29 897,41 8,34 153,16 4,58 25,17
20/80 18,88 867,44 9,37 163,12 5,91 28,34
10/90 20,07 862,27 10,31 205,10 5,74 24,71
b)
g)
Figure 1. Dependence of mixed yarns on the content of nitron fiber a — breaking load, sN; b — relative breaking load, sN/tex; v — time of yarn break, s; g — unevenness on breaking load,%.
The main indicator of the quality of yarn is its breaking load. Therefore, the table shows the breaking load (relative R and absolute P), the break time t and the quadratic unevenness for the discontinuous load C2 {P}.
Based on the data of the table, the dependence of the yarn properties on the content from the nitron fiber,% (Fig.1.), is constructed.
As can be seen from the table, the relative and discontinuous loads change with in the ratio of the components in the mixture. With an increase in the proportion of nitronic fiber, the breaking load first decreases, then (at 70%) begins to increase. This, of course, is due to the resistance of the fibers to the tensile force (Fig.1.). This phenomenon in [1, 25-30] is illustrated as a change in the coefficient of use of fiber strength in the strength of yarn. This, first of all, is due to the difference
in deformation of the fibers. Cotton fiber has a smaller deformation (breaking elongation) compared to a nitrone. With a decrease in the share of cotton fiber, the breaking load and the rupture time decrease until a certain moment, i.e. up to 40% of nitron fiber. Then, the yarn break time and the square yarn unevenness begin to increase, which is most likely due to the difference in the deformation of the fibers of the blended components.
Thus, based on a comparison of the data in Fig.1. it can be said that the maximum breaking load of cotton nitron yarn is between 10 and 20% of the nitrone fiber content. The unevenness of the tensile load has a minimum value of about 17%. The dependencies are approximated using a computer program and the corresponding equations.
Figure 2. Yarn tension curves with different contents nitron fiber: (1-10%, 2-20%, 3-30%, 4-40%, 5-50%, 6-60%, 7-70%, 8-80%, 9-90% of nitronic)
One of the most important indicators of the physical and mechanical properties of any yarn is its ability to resist stretching, which is characterized by a stretching curve. This figure is also considered important because having a smaller breaking load, the yarn can be more resistant to stretching, i. E. have a smaller deformation. In most cases, the fiber in a uniform yarn deforms when stretched almost equally; they have almost equal deformation. The heterogeneous fibers that make up the structure of the mixed yarn are generally deformed differently during stretching. Therefore, the strength characteristics of mixed yarn have special features of deformation under tension. Therefore, the strength of cotton-nitron yarn before the break is great interest from of view of deformation. To investigate this issue, yarn tension curves with different contents of nitron fiber were constructed and studied.
The breaking load of the yarns and the breaking elongation are determined by the method of rupturing a single yarn on a tensile machine. The tensile test was carried out in the "Centexuz" certification center on a tensile testing machine "Statimat-C", which by means of the computer can fix values of a curve of a stretching.
As already mentioned above, the stretch curve is a characteristic of the mechanical properties of the yarn and is used to evaluate it along with the yarn structure. Therefore, the structure and the pre-breaking characteristics of cotton yarn were evaluated. According to the test results of the yarn breaking load, its tension curves are constructed (Fig.2).
Based on a comparison of the stretch curves of cotton yarn of nine variants, it was found that samples of yarn with a low content of nitron fiber, have the maximum resistance to extension (Fig.2., lines 1, 2). The minimum tensile strengths are in the yarn samples, with the maximum content of nitron (lines 8, 9). This picture is due to the fact that a larger content of a low-stretch cotton fiber in the yarn has a greater resistance to stretching, and a highly stretchable nitrone does not exert resistance simultaneously with the cotton fiber. One of the parameters of the pre-breaking characteristics of the yarn is the Young's modulus of the first kind, which is determined when the yarn is elongated to 1%. Therefore, the tension curves were compared with the initial deformation of the yarn (Fig.3.)
Figure 3. Initial deformation of yarn with different content of nitron fiber: (1-10%, 2-20%, 3-30%, 4-40%, 5-50%, 6-60%, 7-70%, 8-80%, 9-90% of nitronic)
As can be seen from the figure, the maximum Young module have yarn samples with a high content of nitrone fiber (curves 7, 8, 9), and the minimal modules have samples with a low content of nitron (curves 2, 3, 4).
It follows that the stretching curves of cotton yarn are not evenly distributed and do not have the same pattern. Taking into account this situation, the change in the dispersion in
strength is studied depending on the fraction of the nitron fiber. With an increase in the fraction of nitron fiber, the dispersion in strength decreases, according to the cubic law (Fig.3.). The spread of yarn strength values for small nitrone fiber contents has the maximum values. With an increase in the fraction of nitron in the mixture, dispersion of the decreases to a minimum value, which indicates the uniformity of the nitron fiber.
Figure 4. Graph of dispersion versus% nitrone
Nitron fiber is undoubtedly more evenly in all respects compared to cotton fiber, and as a result, a greater amount of nitron in the yarn contributes to a more uniform yarn. However, with the index of yarn strength, yarn deformation also grows, which is not always desirable.
Thus, based on the study of the pre-breaking characteristics of cotton nitron yarn, it has been established that the minimum content of nitron contributes to the production of yarn with the greatest resistance to stretching, i.e. with the greatest strength. In this case, the strength dispersion is maximum, and the Young's modulus with an elongation of up to 1% has an
average value. Consequently, depending on the purpose of the yarn, one or another content of the nitrone fiber is selected, i.e. The optimal option is chosen for a specific assortment.
Conclusions:
1. The optimum content of nitron fiber is determined, which is equal to an average of 15%, which ensures maximum tensile load and a minimum unevenness in tensile load of17%.
2. It is established that Young's modules have the maximum value of yarn with a high content of nitron fiber, and the minimal modules possess samples with a high content of cotton fiber.
References:
1. Borzunov I. G. and others "Spinning of cotton and chemical fibers" Part 1.- Moscow, "Light and food industry",- 1982.
