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  • cotton yarn prentation

    cotton yarn presentation

    Published in the:2019-06-27 11:47 Publisher:admin

    I. Introduction of cotton yarn
    Cotton yarn is a yarn made of cotton fiber processed by spinning process, which is called cotton yarn after strand processing. According to the different processes of spinning, it can be divided into universal and combed yarns. (1)Purple yarn:it is a yarn made of cotton fiber by ordinary spinning system. (2)Comb yarn:the yarn made of cotton fiber by combing spinning system. Combed yarns are made of high quality materials. The fibers in the yarn are straight and parallel, with little impurities, good gloss, dry strips and high strength. This kind of cotton yarn is mostly used for woven high-grade fabrics.
    Chinese name: cotton yarn
    The yarn of the quality: the cotton fiber is processed by the spinning process
    classification: comb yarn, combed yarn
    2. Processing and use of cotton yarn
    The production and manufacture methods of cotton yarn are quite complex. generally speaking, there are two spinning methods, general comb spinning and combed spinning.
    The main contents of this paper are as follows: (1) the process of general carding spinning: the finished product inspection is carried out with cotton blending, carding, drawing, roving, roving and roving, respectively.
    (2) combed spinning process: the finished product inspection of cotton blending, carding, spinning, roving, roving and spinning (two kinds of manual windings and automatic windings).
    Cotton yarn is widely used as woven yarn, such as sheets, covers, curtains and other home textile series. It can also be used as knitting yarn, especially combed yarn can be used to produce textiles with high quality requirements, such as high-grade sweatshirts, fine poplin, etc., cotton yarn can also be used to produce electrical yellow wax cloth, tire cord cloth, high-speed sewing thread and embroidery thread for special industry.
    3. Cotton yarn origin and trade area
    Cotton yarn has a long history in China's production and export and has a certain position in foreign trade. The provinces, cities and regions are equipped with cotton yarn production and export capacity, with large output and export volume, including Shanghai, Tianjin, Beijing, Shandong, Jiangxi and other provinces and cities.
    Exports mainly include Europe, USA, Japan, South Korea, South Africa, Russia, Indonesia, Hong Kong and Macao.
    4. Type of cotton yarn
    [經] classification method
    There are many classification methods for cotton yarn.
    (I) according to the custom of thickness:
    Roving yarn: 17 cotton yarns and below are roving yarns. Mainly used for weaving thick or plush, ring cotton fabric, such as coarse cloth, velvet cloth, sturdy, etc. 2 middle branch yarn: 18 × 27 cotton yarn belongs to medium branch yarn, used for weaving plain cloth, twill cloth, tribute satin and other general fabrics; 3 fine count yarn: 28 pieces or more cotton yarn, used for weaving fine cloth poplin, high grade needle, woven fabric.
    (2) According to the spinning principle:
    1 Free end spinning (such as air flow spinning, Siro spinning) 2 two end holding spinning (such as ring spinning, compact spinning) is also popular in recent years is swirl spinning, this textile technology is improved by using the principle of air rotation.
    (3) according to the proportion of cotton and the like:
    1 carding yarn: ring yarn spun by spinning process without combing process, which is used for general needles and woven fabrics;
    2 combed yarn: using cotton fiber of good quality as raw material, adding a combing process compared with ordinary combed yarn when spinning, spinning yarn of good quality, such as advanced poplin, fine cloth, etc., is used to weave high-grade fabrics, such as high-grade poplin, fine cloth, etc., when spinning, it is used to weave high-grade fabrics, such as high-grade poplin, fine cloth, etc. Waste spinning: yarn spun entirely from waste cotton treated in the spinning process, used to weave low-level cotton blankets, velvet and foreskin, etc.
    3 New spinning: yarn spun with a new spinning system.
    4Twist direction:
    (1) warp yarn is a yarn in the direction of parallel cloth edge in woven fabric, which has greater strength and is generally twisted.
    (2) Weft yarn is a yarn with vertical cloth edge in woven fabric, which requires lower strength than warp yarn, twist is generally lower than warp yarn, and maintains a certain softness.
    (3) knitted yarn requires cleanliness, uniformity and small twist to prevent broken ends when weaving and bending. Industrial yarn such as tire cord, conveyor belt yarn, health and medicine yarn, etc.
    (4)according to yarn dyeing and finishing and post-processing points:
    1 original color yarn (also known as primary color yarn): maintain fiber original color for weaving primary color grey cloth;
    2 dyeing yarn: primary color yarn prepared by cooking and dyeing for color weaving;
    3 color spinning (including mixed color yarn): dyeing the fiber first, then spinning the yarn, which can be woven into fabric with irregular star spots and patterns in appearance; Bleached yarn: made of primary color yarn, used in weaving bleach, can also be interwoven with dyed yarn into a variety of yarn-dyed products;
    4 mercerized cotton yarn. Mercerized bleached and mercerized dyed yarns for weaving high-grade colored fabrics;
    5 brimming yarns: the hair on the surface of the yarns is burned off by a bristling machine and made into a yarn withSmooth yarn for weaving high-grade products.
    6 divided into: 1 woven (woven) yarn by use: yarn with twist coefficient greater than 360.2: twist coefficient less than 330
    7 according to yarn forming equipment: ring spinning, airflow spinning (OE), Siro spinning, compact spinning, rotor spinning, swirl spinning, electrostatic spinning, etc.
    8 According to the yarn form, the yarn is divided into the twisted yarn and the cheese.
    V. specifications and quality of cotton yarn
    (1) Cotton yarn specification quality:
    The general carded cotton single yarn specifications are 70 / 56, 55 / 44, 43 / 37, 36 / 29, 28 / 19, 18 / 17, 16 / 10, 9 / 7, 6 / 3 / 2 combed cotton single yarn specifications, and 150 / 131130 / 111110 / 91, 90 / 566, 55 / 4, 43 / 37, 36 / 19, 28 / 19, 18 / 16 by count.
    The yarn for knitting requires that the twist of the yarn is small and the evenness of the strip is uniform, so that the pile of the knitted sweater is thick, the elasticity is good, and the heat preservation property is strong. The yarn for weaving is required to be light, the weft is less and the yarn is uniform.
    (2) Inspection method: according to the national standard, the yarn quality is rated according to the quality index and weight unevenness. The cotton yarn is rated according to the evenness of strip dryness, the number of impurity particles and the number of impurity particles. The quality index mainly refers to the strength of yarn, which reflects the durability and durability of the fabric to a certain extent. The grade of yarn mainly reflects the thickness difference and appearance defect of yarn, which directly affects the appearance of fabric, such as the evenness of texture, clarity and shadow, and so on. Yarn quality is closely related to production management, process conditions, mechanical conditions, technical operation level, advantages and disadvantages of raw cotton and its reasonable use.
    See GB/ T398-93 national standard for technical index of cotton yarn.
    The cotton yarn inspection method shall be in accordance with GB/ T398-93 <cotton-natural-color yarn>; GB/ T4743-95 <yarn density (or count) of yarn; Test method for yarn-twisting method>; SN/ T0450-95 <export-natural-color cotton yarn and combed polyester-cotton blended yarn inspection procedure>.
    The inspection shall be conducted in accordance with the quality specifications and indicators specified in the Trade Contract.
    VI. Various common indexes of cotton yarn
    1) 100 meters dry weight: refers to the drying weight of 100m yarn.
    For example, the 100-meter dry weight of 21s yarn is 2.562g.
    Formula:1)100-meter dry weight = number = 1.085-10
    2) number = 583.1/ 21S
    2) Weight deviation: refers to the range of yarn weight deviation specified per unit length to ensure that the count of the yarn is the same.
    If the weight deviation of the 21 S yarn is 2%, is it reasonable?
    From the above two equations, the 100-meter dry weight of 21S can be determined to be 2.562, and the deviation from 21 S to 2% is worth 2.510, 2.613, for example, the interval value is not exceeded (2.510--2.613), and within a reasonable range.
    3) Weight CV (%): The weight unevenness of each yarn is measured, and the coefficient of variation of the count is also known.
    For example, there are three unknown gauze samples, the weight of 100 meters is 3.653g ≤ 100m, 2.8g ≤ 100m, 0.584g ≤ 100m respectively. What is the number of the above three yarns? What is the linear density? Do you know?
    The answer: the number of expenses is 16s, 21s, 100S.
    The line density is 36.4, 27.8, and 5.84, respectively.
    4) CV (%): refers to the thickness and weight uniformity of the main body of the yarn. Or strip, roving short pieces of thickness uneven.
    The CV value, the coefficient of variation, is also called the standard coefficient of variation. Is a statistical measure of the degree of variation of the observed values in the data. The effect is to reflect the degree of dispersion on the mean value of the unit, and is often used to compare the discrete degree of two or more general mean values. If the two overall mean values are equal, the comparison standard deviation coefficient is equivalent to the comparison standard deviation.
    5) fracture strength, coefficient of variation between fracture strength and fracture strength CV (%)
    Yarn strength, also known as breaking strength. Refers to the maximum tension of a single yarn or bunch of fibers when broken, in the unit of Niuniu. There are generally indexes such as average strength and minimum strength.
    1. Breaking strength: the maximum tensile force that the yarn can bear. The unit is N (N). The test speed is 5 m/ min.
    2.Fracture strength: the maximum tensile external force per Tex can bear. The unit is N / T. Tex is the number of yarns.
    3. The coefficient of variation of the breaking strength CV (%): the strength unevenness of the yarn.
    6), yarn defects: coarse section 50%, detail-50%, cotton knot 200%
    1. Coarse section+50%:the part of the yarn diameter exceeds 50%of the yarn body. Unit:pieces/km.
    two。 Detail-50%: the yarn diameter is less than 50% of the yarn main body. Unit: unit / km.
    3. Js: it is made of fiber, immature cotton or rigid cotton, due to poor rolling quality or poor treatment in the spinning process. More than 200% of yarn defects.
    7) Twist: when the gauze rotates 360 degrees around its axis, it is a twist. Twist refers to the number of twists and turns of yarns in a certain length, unit: unit / 10cm.
    1. S-twist: The direction of the fiber in the sliver is in line with the middle of the letter S.
    2. Z-twist: The oblique direction of the fiber in the sliver is consistent with the middle of the letter Z.
    3. The general single yarn is usually Z-twisted and the strands are S-twisted.
    4. By twisting the yarn, the breaking strength increases, and the wrinkle resistance and wear resistance also increase. However, the twist should not exceed a certain value, otherwise, the strength decreases, and it is difficult to dye.
    8) Hairiness: hairiness H value, standard deviation of hairiness Sh, coefficient of variation of hairiness CVh
    1. Feather value H refers to the cumulative length of the fiber extended from the outside of the yarn in the range of yarn 1cm, calculated in millimeters.
    Two. The hair feather value H is related to yarn number and twist. The finer the yarn, the less the number of fiber roots in the cross section of the yarn, and the smaller the number of hair feathers outside the yarn, the greater the twist of the yarn, the greater the chance of hairiness twisting into the yarn, and the less hairiness.
    3. Hairiness H value will have a negative effect on yarn dyeing.
    4. Feather yarn: a small piece of yarn with a continuous fiber end protruding from a feather-shaped yarn outside the yarn.
    9) original yarn quality: it includes the appearance quality and internal quality of the original yarn. The appearance quality of the original yarn mainly refers to the color of warp and weft yarns, knotted impurities, strip dryness, hairiness and so on. Internal quality mainly refers to the strength, strength and extension of warp and weft yarns.
    10) cotton knot impurities: hard knot dead cotton and sundries existing in the original yarn fiber. The cotton knot impurity refers to the hard knot dead cotton and sundries that exist in the original yarn fiber. The amount of impurities is related to fiber maturity, water content and processing quality.
    7. Reference to the appearance Inspection Standard of Cotton Yarn
    Yarn appearance quality (combination of visual and hand feel)
    1.1 Yarn must go through air splicing and electronic yarn cleaner, requiring fixed weight or length.
    1.2 No oily yarn, coal ash yarn, color difference, no wrong branch, heterosexual fiber according to customer standards, the standard range is as follows:
    1 overlap: the two ends of the bobbin are higher than the original yarn plane; more than 18 (less than 32) 0.15 cm, 0.3 cm wide; less than 18 (more than 32) 0.25 cm,. 0.4 cm wide; more than 5 cm long is not allowed, less than 5 cm allowed one place. Second floor platform: single end protruding more than 0.3 cm is not allowed.
    Wrong count: No matter how much is not allowed.
    Oil pollution (including color stains / mildew): neither depth nor size is allowed.
    4 two-story platform: single end protruding more than 0.3 cm is not allowed.
    Net yarn: the net is not allowed, the large end of a single jump yarn is allowed to be 2 cm and the following 3 roots,2 cm or more is not allowed, and 2-4 cm of 2 roots are allowed at the small head.
    Severe impression of the bobbin is not allowed.
    Chrysanthemum core: tube meridional more than 1.5 cm is not allowed.
    8 grooves: depth more than 0.25 cm is not allowed.
    9 loose yarn belt yarn small braided yarn gourd yarn color difference grinding tube deformation and flanging bobbin surface and packing with flying silk are unqualified yarn.
    ©If the raw head yarn to be made shall not be less than 13cm, it shall be wrapped around the bottom of the tube, which shall be attached to the surface.
    1.3 No coarse section, long detail yarn defects.
    1.4 The broken ends and heads caused by wear and other reasons inside and outside of the yarn are not allowed.
    1.5 single yarn, strands should not have strong twist or weak twist (compared with normal yarn).
    1.6 There is no double-strand yarn in single yarn, and there are no three-strand yarn and multi-strand yarn in the strand.
    1.7 if the quality of the trial woven cloth surface does not meet the requirements or the decapitation exceeds the standard (the standard is 5 million meters, the number of decapitated roots is more than 8 × 10) and is judged to be unqualified.
    1.8 The yarn must be provided with a small sample (about 5 cm thick in general) for 15 days in advance to identify and test the original yarn index, and finally determine whether the various indexes of the original yarn are qualified.
    1.9 If the large sample index does not match the small sample index, contact the manufacturer in time.
    1.10 The same type of paper tube is used; different varieties can not be used in the same paper tube, and different manufacturers require different paper tube colors, so that the color of the same paper tube can be avoided, and the color of the same paper tube can be avoided.
    2 appearance forming requirements of bobbin yarn
    Flying flowers, filaments and other sundries are not allowed in the bobbin. There can be no obvious concavity and convexity on the surface of the bobbin, and no obvious breakage and deformation of the bobbin. In order to prevent warp breakage, the maximum diameter of the yarn does not exceed 21 cm, air spinning 22 cm, and prevent excessive loosening.
    VIII. Cotton yarn packaging, storage and transportation
    Cotton yarn can be divided into bobbin yarn and twisted yarn according to different uses.
    The inner packing of cotton yarn is a plastic bag with factory name, product name and specification, registered trademark name, grade, weight, batch number, package number, number of bobbin yarn and packing date.
    Cotton yarn outer packaging cartons or plastic bags, packaging should be neat, dry, strong, suitable for long-distance transportation.
    The inspection of cotton yarn is valid, the north is one year, and the south is half a year. It must be checked beyond the validity period. Main items for inspection: mildew, moth, water, pollution, breakage, etc.
    9. Matters needing attention in cotton yarn
    Due to the different producing area and batch number of cotton, the performance of cotton is also quite different. Therefore, it is necessary to mix cotton with different batches in processing. When signing the contract, we should pay attention to the clear batch of cotton yarn and prevent uneven dyeing in the process of use.
    Ten, cotton yarn micronaire value
    the horse cloning value of the cotton fiber is a comprehensive reflection of the fineness and the maturity of the fiber, and the maturity is different, not only can cause the change of the fiber property, but also has great influence on the yarn forming process, the quality and the fabric quality, the horse clone value of the cotton fiber can be used as a comprehensive index for evaluating the inherent quality of the cotton fiber, directly affecting the color, strength, fineness, natural property, elasticity, moisture absorption, dyeing and the like of the fiber, And is not suitable for spinning high-grade cotton yarn. The horse clone value is in the range of 4.1 to 4.3, the growth period is short, the under-maturity is low, and the relative coat rate is lower, but the fiberThe yarn has the advantages of fine fineness, high fiber single, large number of fiber roots in yarn cross section and high strength, so it can be spun into medium and high grade cotton yarn.
    11. A brief introduction to the Development of Cotton Yarn
    In December 2008, the yarn output of enterprises above the national scale was 1.8602 million tons, down slightly from November. In 2008, the cumulative yarn output of enterprises above the national scale reached 21.4892 million tons (enterprises above the scale), an increase of 8.1 percent over the same period last year.
    Among them, the output of cotton yarn was 1.541257 million tons, which was basically the same as that in November, and the cumulative output in 2008 reached 17.3733 million tons, an increase of 10.56 percent over the same period last year. In December, the output of blend yarn was 224900 tons, up 6 percent from 21.16 in November, and the cumulative output in 2008 reached 2.525 million tons, down 0.59 percent from the same period last year. In December, the output of purified fiber yarn was 134600 tons, an increase of about 3 percent over the output in November. In 2008, the cumulative output reached 1.5905 million tons, down 2.17 percent from the same period last year.
    the quotation in 2010
    In 2010, the mainstream quotation of 32s carding machine yarn market is 24500 yuan / ton, combed yarn quotation is 27500 yuan / ton, 40s general carded yarn quotation is 25500 yuan / ton, combed yarn quotation is 28500 yuan / ton.
    2012 cotton yarn price market
    In 2012, the mainstream quotation of 24s pure cotton yarn market was 21300 yuan / ton, 19500 yuan / ton of mixed yarn, 23500 yuan / ton of 18s general combed yarn, and 22500 yuan / ton of combed yarn.

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