It matures about 7 months after planting. It is grown in many countries in the world (America, India, China, Egypt, Greece, Turkey, etc.). Picking time varies according to the climate, but it is always after the hot season. Cotton is harvested by hand or by machine.
The advantage of machine picking is low cost and less contamination; The disadvantage is that it may contain immature cotton (dead fiber) since the cotton is collected at once.
In Turkey, cotton is generally picked by hand, and in some regions, work has been carried out on mechanical agriculture in recent years. Wind, rain and sun can cause different appearances even in cotton in the same field.
In the cotton plant, the cocoon and core must be separated from the fiber in special machines, which cotton ginning is called. The cotton ginned is turned into bales. The cotton standard applied in Turkey includes the color of the cotton, foreign matter (trash) and preparation status.
In the standard, white, slightly spotted, yellow spotted and gray starting from 1 and max. Grades up to 6 are available.
Standard White 1 (St1), standard slightly mottled 2 (HB2) etc. In the American cotton standard, the physical properties of the cotton measured by the device are used. (Midling, strict midling etc.) The most important parameter affecting the quality and price of cotton is fiber length. The higher the fiber length, the higher the yarn and fabric quality.
As the uniformity (fiber length distribution ratio) of the cotton fiber increases, the micronaire decreases, the color becomes whiter and the appearance brighter, and the strength increases. cotton quality improves as trash (the proportion of vegetable residues in it) decreases. Cotton should be selected in accordance with the yarn count (Ne) to be produced and the place of use of the yarn (weaving, knitwear, etc.).
In Turkey, cotton is grown in the Aegean, Çukurova and Southeastern Anatolia regions. The most important factor that determines the type and characteristics of cotton is the seed used, climatic conditions and agricultural operations.
Type samples of cottons were determined based on the ginning method and production region as shown below:
a) Short fiber (domestic) group cottons, medium fiber (upland) group cotton ginned with sawgin
A single type of sample is prepared and called (TURKEY) in long fiber group cottons, linter cottons, fiber waste cottons, medium fiber (upland) group rollergin colored class and non-type cottons.
b) Aegean type cotton ginned with medium fiber (upland) group rollergin;
1) A single type sample is prepared in the Aegean production region (Izmir, Menemen, Bergama, Manisa, Turgutlu, Salihli, Alaşehir, Balıkesir, Tire, Torbalı, Söke, Aydın, Nazilli, Denizli, Milas, Köyceğiz, Ödemiş and Bursa control centers) and (TURKEY-AEGEAN),
2) A single type sample is prepared in Antalya, İskenderun, Antakya, Iğdır, Kahramanmaraş, Gaziantep, Adana, Mersin, Ceyhan, Osmaniye, Reyhanlı, Nusaybin, Diyarbakır, Şanlıurfa production regions and control centers and (TURKEY-AEGEAN TYPE),
3) Cottons suitable for this type of samples in other production regions and control centers (TURKEY-AEGEAN TYPE),
is called.
c) In Çukurova type cotton ginned with medium fiber (upland) group rollergin;
1) A single type of sample is prepared in Adana, Mersin, Ceyhan and Osmaniye production areas and control centers and (TURKEY-CUKUROVA),
2) Cottons suitable for this type of samples in other production regions and control centers (TURKEY-CUKUROVA),
is called.
The ratio of foreign matter content of medium fiber (upland) group cottons in terms of class and type, and color grades in HVI (High Volume Instruments) were determined as shown above:
Foreign matter is only cotton leaves, bark pieces, flower or stem fragments and dust. Other substances other than these are not considered foreign substances, if present, the lot is rejected.
It is obligatory to purchase and sell pressed cottons with the control document shown below.
Pressed cotton bales;
a) Gross weight of at least 190 kg,
b) Its dimensions are at most 65x95x105 cm,
It has been determined.
In order to make bales in these sizes, considering the expansion share of the bale after exiting the press;
a) Maximum 60x90 cm in width and length,
b) Its height is at least 190 kg according to the pressure of the pressing machine. It should be to the extent that XNUMX
The 105 cm height of the pressed cotton bales, which have been internally controlled and desired to be exported, can be reduced to 50 cm in high-pressure press machines.
RELATIONS BETWEEN FIBER AND YARN PROPERTIES
The long length (long staple), thinness (low micronaire) and high fiber strength (high pressley or high maturity degree) of cotton fiber used in yarn manufacturing affect yarn strength positively. Again, high fiber length and low micronaire value, produced It also positively affects the degree of evenness of the yarn. The yarn spinning limit, that is, the thinnest yarn limit that can be spun from the fiber, is primarily limited by the fiber fineness. As the fiber gets thinner, the number of fibers in the cross-section increases and the yarn strength that allows the yarn to be spun is provided. The minimum number of fibers in the yarn cross-section depends on the yarn manufacturing method. This number is around 65-88 in cadre yarns and around 33-59 in combed yarns. In addition, the twist coefficient of fiber fineness (the ability to bend increases as the fiber gets thinner), the yarn strength and smoothness of the percentage of short fiber (as the percentage of short fiber increases, the yarn strength decreases and the unevenness increases. ) and the amount of foreign matter in cotton Especially in the Open-End mill, they have an effect on the number of ends down (the number of ends down increases as the amount of foreign matter increases).
NUMBERING COTTON YARNS:
The thinness and thickness of the yarns are indicated by their numbers. Numbering is done in 2 ways.
1-Length Numbering System: (Length is variable, weight is fixed)
2-Weight Numbering System: (Weight is variable, length is fixed)
British cotton yarn system is used for numbering cotton yarns. Number British cotton ; The length is in the numbering system. The yarn from 840 yards to 1 Pound is Number 1 British Cotton. The number is indicated by British Cotton NIP or NEC
(1 Pound = 453,6 grams) (1 Yard = 91,44 cm) (840 Yards = 768 meters)
For example; If the yarn weighing 453,6 g is 15.360 m (20 x 768 m), its number will be 20 NIP.
WORK OF COTTON IN THE SPINNING :
Cotton in the short fiber spinning mill is used both purely and mixed with flax and chemical fibers in the manufacture of yarn. The natural twisting of cotton provides convenience during production. neps usually occur in two ways;
1- As a result of the immature fibers and dead fibers coming together in the cocoon during the development of cotton,
2- As a result of damage to the fibers in the ginning and during the manufacturing in the spinning mill card under faulty working conditions (worn and faulty clothings, incorrect adjustment and excessive number of passages).
The increase of foreign materials in the cotton requires an increase in the number and efficiency of the cleaning process to be applied in the spinning mill. As a result of not cleaning the foreign materials in the cotton sufficiently and not absorbing the microdust remaining in the cotton as a result of the Saw Gin ginning, yarn breaks in the rotor cavities of the Open-End yarn method, especially in quality and productivity. falls occur.
The blowroom and comb are the most important passages in separating the seed shards and foreign materials from the cotton. With the advancement of yarn technology and the increase in production, the importance of stickiness in cotton has increased to a great extent. The stickiness in the cotton, which shows, causes machine downtimes and thus production losses.
SHORT FIBER SPINNING
When cotton spinning is mentioned, short fiber spinning generally comes to mind. In this system, natural and artificial fibers shorter than 60 mm are processed. Although some parts of the machines used in converting natural and artificial short fibers into yarn vary, they are the same in principle.
Short fiber spinning mill is known in the market as “Cotton spinning mill”. Cotton and cotton synthetic blends are working in this spinning mill. Ring yarn production and Open-End yarn production are made in cotton spinning mills as seen in the process flow chart below. Carded yarn and combed yarn production are also observed in the ring yarn mill it crashes.
Open-End Spinning Mill:
1-Raw material 2-Harman-Hallaç 3-Card Machine 4-First (1st) Passage draw machine 5-Second (2nd) Passage draw machine 6-Rotor Spinning machine
Ring spinning mill : ( Carded )
1-Raw Material 2-Blow Room 3-Card Machine 4- First (1st) Passage Draw Frame 5-Second (2nd) Passage Draw Frame 6-Roving Machine 7-Ring Spinning Machine 8-Bobbin Machine
Ring spinning mill : ( Combed )
1- Raw Material 2-Blow Room 3-Card Machine 4- First (1st) Passage Draw Frame 5-Combing Preparation Machine 6-Combing Machine 7- Second (2nd) Passage Draw Frame 6-Roving Machine 7-Ring Spinning Machine 8 -Coil Machine
The processes that the cotton undergoes until it reaches the spinning mill are ginning and pre-cleaning. The cotton fiber separated from the seeds in the ginning factories is turned into bales. It is brought to the spinning mills in this form. There are also vegetable crumbs such as seeds, leaves, grass, etc., and mineral-containing foreign materials such as sand and dust in the cotton fibers. Before starting the spinning process, it is necessary to purify the fibers from such substances as much as possible. Therefore, the first operation to be carried out in the spinning mill is to open and clean the cotton bales after they are freed from the presses and after they are air-conditioned (conditioning). This opening and cleaning process is done in the threshing-room machine. Afterwards, finer cleaning and making the fibers parallel to each other are provided in the carding machines. In addition, a band form is given to the fiber. smoothness and fiber parallelism are improved. For this purpose, drafting is applied. The tapes coming out of the frame are thinned in the roving machine and turned into roving. The rovings obtained are also thinned and twisted into yarn by ring spinning machines.
The main difference between the production of carded and combed yarns is that combing preparation and combing machines are added to the production line. In the combing preparation machine, many bands are brought together to form a ball. These balls are then fed to the comber and processed there. is the removal of foreign materials and short fibers.
When we compare combed yarns with carded yarns, it is seen that combed yarns have the following advantages.
1-It does not contain foreign materials and fiber knots.
2-Fluffing is minimized.
3-They look neat.
High fiber quality in combed yarns can reduce the number of twists for the spindle. This ensures that the products produced have a softer handle. It is especially important in knitwear products. As raw material waste increases and the number of processes increases, some cost difference naturally occurs.
Cotton yarns are generally produced in classical machines called ring spinning machines. All kinds of yarns can be produced in wide number limits in these machines. One of the most important problems in ring spinning is the short fibers between the fibers. Due to some distinctive technical reasons, the production speed is not high. Therefore, an alternative to ring spinning is not possible. Set of modern production systems have also been introduced to the market. The most developed of these is open-end rotor spinning. The market share of these yarns, which are only called open-end yarns in the market, is around 25%. With this method, cotton, artificial fibers and their blends can be easily processed. If short fiber is the problem On the contrary, short fibers such as combed waste can be added to the blend to produce economically. However, in addition to such an application, combed fibers are also used in the Open-End machine for the production of high quality yarns. Open-End yarns are very different from ring yarns in terms of structure. In ring yarns, the fibers lie parallel to each other along the yarn. In this way, a very strong joint is formed with their placement. Open-End yarns are more complex and the fiber parallelism is quite low. shaped fibers are entangled. Since the parallelism is low, their strength is 10-20% less than ring yarns. Therefore, it is necessary to apply more twist than ring yarns.
Physical Properties of Cotton Fibers
The production of seed cotton in the world was 2012 million tons in the 2013-76,5 season. The amount of cotton fiber in the same season is 27,5 million tons. In Turkey, 2013 thousand tons of seed cotton was produced in the 2014-843 season. On the other hand, the textile industry needs in Turkey. The amount of unseeded cotton is over 1,5 million tons.( Knitting World Kasam-December 2014 Issue: 65)
The primary wall is formed from the elongation of the epidermis cell around the seed. In the fiber maturation phase, a secondary wall is built from cellulose inside the primary wall in 20 days. Cotton fiber is a thin-walled plant cell filled with protoplasmic fluid. The outermost layer of the cell is the cuticle layer, under which there are primary and secondary structures.
Physical appearance and parts of cotton fiber
The secondary structure consists of three parts. These are two fibrillar structures towards the center, respectively, and a structure called the lumen in the center, which surrounds the channel filled with protoplasm fluid. When the plant matures and the cocoons open, the protoplasm fluid dries up. During this drying, the cross-section of the cell takes the shape of a bean and a collapsed structure is formed on one side.
The maturation process of cotton fiber
When we look at the cross-section of the fiber under the microscope, it is seen that it is like a twisted strip that narrows towards the ends. The secondary structure in the fibers of the cotton, which cannot develop during production, cannot fully develop. This type of cotton is called dead cotton..
1-Cotton fiber is creamy white in color,
2-The length of cotton fiber varies from 1cm to 7,5cm,
3- Its diameter is 6–25μm (μm=10 -6m),
4-Intensity is between 1,50–1,55,
5-In standard conditions (20°C temperatures and 65% reactive humidity) 8,5% moisture adsorbs, Cotton easily absorbs moisture from the air. However, it may feel dry when handled.
6-The maximum amount of humidity allowed in trade is 8,5%,
7 - At 100% reactive humidity, cotton material absorbs 25-27% water,
8-The average elongation amount of the fiber is 7-8% on average,
9- It does not have elastic properties. Recovery after 2% elastic elongation is 74%, after 5% elongation it is 45%,
10-The shortening in length and width when wet, which is seen in all cellulosic materials, is also observed in cotton material. This shortening is due to swelling in the cotton fiber,
11-As with all cellulosic fibers, cotton also increases in durability when wet. Stamina increase is around 30%,
12-Cotton materials absorb water up to 70% of their weight when wet.
The physical properties of cotton, which is the most produced and consumed natural fiber, significantly affect the quality of the yarn to be obtained from it. While separate devices were used to measure the properties of cotton fibers in the past, modern devices called HVI and AFIS have been used today. AFIS in bundles is the measurement of individual fibers. with results.
Chemical Properties of Cotton Fibers
The chemical structure of cotton fiber varies according to growing conditions. In its chemical structure;
1-Cellulose,
2-Hemicellulose and pectin,
3-Protein and colored matter,
4-Inorganic substances,
5-Wax and oils
located.
Since cotton fiber contains nearly 100% cellulose, it shows all the chemical properties of cellulose.
1-Decomposes with concentrated and strong acids in hot and cold temperatures,
2-It is completely soluble in concentrated sulfuric acid,
3- Dilute bases have little effect on cotton,
It starts to decompose at temperatures above 4-150°C, it is roasted in a short time at 170°C,
5-If it stays in contact with oxidizing bleaches for a long time, it decomposes with the formation of oxycellulose,
6- Polymer deteriorates in cotton that is exposed to UV rays in sunlight, air oxygen, humidity and polluted air conditions. Direct sunlight, especially in hot and very humid weather, affects the cotton material, reducing its durability.
ADHESION OF COTTON FIBERS
Stickiness is an undesirable feature that creates serious problems for businesses. It is possible to determine the stickiness caused by whitefly pests by various chemical methods and aluminum foil (Thermic method) method, and it is of great benefit to test especially when it comes to going out of a conventional cotton variety. In addition to the aluminum foil method, a chemical method called "Clinitest" is also used in the fixation. The stickiness is also called sugar or honey.
ELEMENTS THAT DEFINE THE GRADE OF COTTON FIBER
1-color of cotton (white, dyed, stained, blue and ash color)
2-Containing foreign matter (only cotton plant leaves, bark pieces, flowers, stem scraps and dust) amount
3-Condition of cotton in preparation (good or bad gin)
contamination
It is the incorporation of the yarn into the cotton fiber as a result of the mixing of materials other than cotton in any way due to the collection-ginning and packaging from the field..
Apart from this, due to bad collection and ginning of the cotton, the trash and seedling broken, or the seed bark piece remaining at the end of the fiber, or the oil extraction as a result of crushing the seed, and the lack of adequate agricultural control, as well as other reasons such as; Factors such as the stickiness on the tips of small leaves that reappear due to delay after the use of defoliant before harvesting during machine harvesting, or the stickiness produced by the plant under stress due to the increase in temperature difference between day and night, are not included in the definition of contamination.
Again, similar neps and dead fibers cannot be added to this section. Neps is one of the faults in ginning and dead fiber is caused by untimely spraying, irrigation and especially collecting, depending on climatic conditions.
BASIC PROPERTIES OF COTTON
The structure of cotton consists almost entirely of pure cellulose.
LENGTH OF COTTON FIBER
Measuring the fiber length is done with the fibrograph device (fibraograph unit for HVI). The length values obtained in this device are expressed in terms of span length (SL), and generally 2,5% SL and 50% SL values are obtained from the fibrograph device. value is also calculated. Classification of fiber length (stapel) according to average fiber length; (without considering the short fiber part)
1-Short staple
2-Middle staple
3-Long staple
It is analyzed in 4 categories as 4-Extra long staples.
FINNESS OF COTTON FIBER
It is expressed in micronaire and is dimensionless.Micronaire sheffield is an instrument for detecting the fineness of cotton fibers.Classification of fineness according to the order according to Micronaire values ;
1-Very thin
2-Thin
3-Mediocre
4-Bold
It is examined in 5 categories as 5-Very Thick.
STRENGTH OF COTTON FIBER
It is given in pounds/square inch in the international cotton trade. It is determined with the Pressley instrument. Pressley fiber strength;
1 very strong
2- Strong
3-Mediocre
4-Not bad
5-Weak.
ELASTICITY OF COTTON FIBER
It is an important factor, especially in the form we can define as elongation at break. the behavior of the thread in the face of sudden stresses it encounters. This value varies between 6-10% for cotton. Elongation at break is measured simultaneously with the breaking strength of the fibers..
MATURITY OF COTTON FIBER
It is determined by various methods and the cotton maturity ranking expressed in %;
> 82 mature
76-81 At mediocre maturity
70-75 Raw
70 It is made very raw.
Maturity is important in terms of dyeing. Since immature fibers will not take dye, it causes quality problems.
CLASSIFICATION OF COTTON FIBER
Our country's cotton; It is divided into three as short fiber, medium fiber and long fiber.. Medium fiber cottons produced in 99% of our country According to their color, they are divided into classes as white, slightly mottled, colored and out of type. Each grade is classified according to ginning, preparation and foreign matter ratio. quality grades such as "Standart Extra, Standard 1, Standard 2" are separated. Standard type cotton samples should be prepared separately for each production region such as Aegean, Çukurova and Southeastern Anatolia regions. cottons Groups according to their ginning patterns, grades according to their colors and lengths according to fiber lengths. are separated. Elements that determine the character of cotton; fiber length as well as the fineness, durability and flexibility of the fiber.
LONG FIBER COTTONS
They are cottons of the Gossypium barbadense L. type and their fiber length is 30.48 mm. and it is longer. Types of long fiber cotton grown in our country (Sea Land, Delcerro, etc.) are classified into 4 types with their own names.
With linter cottons, the class and types of fiber waste cottons that occur during yarn production have been determined and named as follows:
a) Linter Cottons:
The definitions of the classes and types of linter cottons obtained by cutting the fibers remaining on the cotton seed in linter machines have been determined as follows:
1) Class A:
These are cottons obtained by cutting the fibers remaining on the cotton seed with linter machines once.
Types:
1.1) Linter (A-1): It is cotton with light color (off-white), less foreign matter, very little short fiber obtained by cutting the fibers remaining on the cotton seed once in linter machines.
1.2) Linter (A-2): Linter (A-1) is a slightly darker colored cotton with more foreign matter and less short fiber.
1.3) Linter (A-3): It is darker colored cotton than Linter (A-2) with more foreign matter and short fiber.
2) Class B:
These are cottons obtained by cutting the fibers remaining on the cotton seed after the first cutting for the second time.
Types:
2.1) Linter (B-1): It is light brown cotton that does not contain short fibers and has foreign material, obtained by cutting the fibers remaining on the cotton seed after the first cutting for the second time.
2.2) Linter (B-2): It is cotton with more foreign matter and darker brown color than Linter (B-1).
3) Non-Type Class:
These are cottons that are not in linter A and B classes, and burned and damaged linter cottons.
b) Fiber Rash Cottons:
The classes of fiber waste cotton obtained during ginning and spinning were determined as follows:
1) Ginning fiber waste:
Oily, oily, lint-like and cyclone dust produced during ginning can be classified as clean or dirty by typing cottons based on the place where they occur (obtained).
2) Yarn manufacture fiber waste:
Lap edge, strip, roving, ring, saw, hat, drum, fine comb, under room chamber, room fluff, cellar dust, square waste, roving scrap from vigon reed, large drum waste and under-loom waste obtained during yarn manufacturing Fiber waste cotton can be classified as clean or dirty by typing according to the way it occurs (space, machine, product).
MEDIUM FIBER ( UPLAND ) COTTON
1) White Class:
It is unstained (spotless) in brightness and vitality, which contains the natural color of the type.
Types:
1.1) Standard Extra: They show the highest degree of white color and brightness, and they are perfect cottons with almost no foreign matter and no ginning faults.
1.2) Standard 1: It is a bright white cotton that is not in the extra class, has a little more foreign matter than the extra, does not have any pest damage or ginning defect.
1.3) Standard 2: Cottons that have a slightly dulled color compared to Standard 1, have a little more foreign matter, have turned brown in color, have no pest damage and have the least ginning error.
1.4) Standard 3: Cottons that are slightly duller than standard 2, light gray in color, foreign matter more than standard 2 and blackened, with less ginning errors and less pest damage.
1.5) Standard 4: It is more dull than standard 3, slightly grayer, foreign material is more than standard 3 and blackened, has ginning faults and pest damage, includes immature cottons, and has stains that cannot be considered mottled.
1.6) Standard 5: These are cottons whose color has become more dull and gray compared to standard 4, foreign matter is a little more than standard 4, and has stains that are not in the light mottled class.
2) Light Spotted Grade:
It is the mottled one of all types of cotton in the white class due to rain, collection and storage conditions.
Types:
2.1) Standard 1: White standard 1 cotton is slightly mottled due to rain, collection and storage conditions.
2.2) Standard 2: Due to the rain, collection and storage conditions of the white standard 2 cotton, the spot condition and size are slightly more than standard 1.
2.3) Standard 3: Due to the rain, collection and storage conditions of the white standard 3 cotton, the spot condition and size are slightly more than standard 2.
2.4) Standard 4: Due to the rain, collection and storage conditions of the white standard 4 cotton, the spot condition and size are slightly more than standard 3.
2.5) Standard 5: Due to the rain, collection and storage conditions of the white standard 5 cotton, the spot condition and size are slightly more than standard 4.
3) Color Class:
They are cottons that have turned into very light brown, light brown, brown and dark brown as a result of the ginning of the unseed cottons that have been eaten by rain and frost or collected in excessive humidity, and which have been fermented as a result of being stored in warehouses for a long time and under bad conditions.
Types:
3.1) Color 1: These are cottons whose color turns very light brown due to frost, frost effect and fermentation.
3.2) Color 2: It is the one whose color turns slightly brown due to frost, frost effect and fermentation.
3.3) Color 3: These are cottons that turn brown in color due to frost, frost and fermentation.
3.4) Color 4: These are cottons whose color turns dark brown due to frost, frost effect and fermentation.
4) Non-Type Class:
White, slightly mottled and non-colored cottons are produced by processing cotton that has excess foreign matter (including soil), oil-contaminated, pressed cotton bales exposed to fire and flooding, and falling down with seed.
Types:
4.1) Non-Type (Disabled): These are the ones obtained by ginning of unseeded cottons with excessive amount of foreign matter and soil, and those consisting of oily and foamy fibers accumulated at the ball heads during ginning.
4.2) Out of Type (Full Head): It is obtained as a result of processing the cotton that falls down with the seed during ginning.
4.3) Non-Type (Avarian): These are cottons that are produced as a result of exposure of pressed cotton bales to fire and flooding.
SHORT FIBER ( LOCAL ) COTTONS
Gossypium herbaceum L., Gossypium arboreum L. are cottons with fiber lengths shorter than 19.05 mm. The types and definitions of cottons included in the short fiber (domestic) group have been determined as follows:
1) Native 1:
It shows the highest white color and brightness of its group, has almost no foreign matter and no ginning defects.
2) Native 2:
Compared to domestic 1, it has a slightly duller color, a little more foreign matter, a brownish trash color, and less ginning errors.
3) Native 3:
Compared to the domestic 2, it is slightly more dull and grayed in color, its foreign material is black and has a ginning defect.
GROUP OF COTTONS ACCORDING TO THE TYPE OF ginning
Rollergin:
They are cottons obtained by ginning in the ginning machines that separate the fibers from the grain with the cylindrical and rotating balls (role) system covered with leather, rubber and similar materials.
Sawgin:
They are cottons obtained by ginning in saw ginning machines that separate the fibers from the grain with the circular and rotating saw system.
Lintergin:
They are the cottons obtained as a result of the separation of the fibers remaining on the cotton seed with sawed linter machines.
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