Cotton Fibers 2


Once Valledupar's main economic produce; Cotton
Image via Wikipedia

WHAT IS COTTON?:

COTTON is defined as white fibrous substance covering seeds harvested from Cotton Plant.

SEED COTTON (called Kapas in India – Paruthi in Tamil)harvested from Cotton Plant.

LINT COTTON (RUIA in Hindi, PANJU in Tamil) is obtained by removing the seeds in a ginning machine.

LINT COTTON is spun into Yarn, which is woven or knitted into a Fabric. Researchers have found that cotton was grown more than 9000 years ago. However large scale cultivation commenced during middle of 17th Century AD.

Many varieties of Cotton are cultivated mainly from 3 important genetic species of Gossipium.

G. HIRSUTUM – 87% Grown in America, Africa, Asia, Australia Plant grows to a height of 2 Meters.

G. BARBADENSE– 8% Grown in America, Africa & Asia. Plant grows to a height of 2.5 Meters with yellow flowers, long fibers with good quality, fibers with long staple and fineness

G. Arboreum – 5% Perennial plant grows up to 2 meters with red flowers, poor quality fibers in East Africa and South East Asia.

There are four other species grown in very negligible quantities. Cotton harvested from the Plant by hand – picking or machine picking is ginned to remove seeds and the lint is pressed into Bales for delivery to Spinning Mills. Cotton is Roller Ginned (RG) or Saw Ginned (SG) depending varieties and ginning practices.

Cotton is cultivated in 75 Countries with an area of 32 Million Hectares. Cultivation period varies from 175 days to 225 days depending on variety. Cotton is harvested in two seasons, summer and winter seasons.

Saw ginned cotton is more uniform and cleaner than Roller Ginned Cotton. But fibers quality is retained better quality in Roller Ginning than Saw Ginning which has high productivity.

Cotton Fiber is having a tubular structure in twisted form. Now. researchers have developed coloured cotton also. As on date, percentage of Cotton fiber use is more than synthetic fibers. But, its share is gradually reducing. Cotton is preferred for under garments due its comfort to body skin. Synthetics have more versatile uses and advantage for Industrial purposes.

PROPERTIES OF COTTON

No other material is quite like cotton. It is the most important of all natural fibres, accounting for half of all the fibres used by the world’s textile industry.
Cotton has many qualities that make it the best choice for countless uses:
Cotton fibres have a natural twist that makes them so suitable for spinning into a very strong yarn.
The ability of water to penetrate right to the core of the fibre makes it easy to remove dirt from the cotton garments, and creases are easily removed by ironing.
Cotton fabric is soft and comfortable to wear close to skin because of its good moisture absorption qualities.
Charges of static electricity do not build up readily on the clothes.

HISTORY OF COTTON

Nobody seems to know exactly when people first began to use cotton, but there is evidence that it was cultivated in India and Pakistan and in Mexico and Peru 5000 years ago. In these two widely separated parts of the world, cotton must have grown wild. Then people learned to cultivate cotton plants in their fields.
In Europe, wool was the only fiber used to make clothing. Then from the Far East came tales of plants that grew “wool”. Traders claimed that cotton was the wool of tiny animals called Scythian lambs, that grew on the stalks of a plant. The stalks, each with a lamb as its flower, were said to bend over so the small sheep could graze on the grass around the plant. These fantastic stories were shown to be untrue when Arabs brought the cotton plant to Spain in Middle Ages.

In the fourteenth century cotton was grown in Mediterranean countries and shipped from there to mills in the Netherlands in western Europe for spinning and weaving. Until the mid eighteenth century, cotton was not manufactured in England, because the wool manufacturers there did not want it to compete with their own product. They had managed to pass a law in 1720 making the manufacture or sale of cotton cloth illegal. When the law was finally repealed in 1736, cotton mills grew in number. In the United States though, cotton mills could not be established, as the English would not allow any of the machinery to leave the country because they feared the colonies would compete with them. But a man named Samuel Slater, who had worked in a mill in England, was able to build an American cotton mill from memory in 1790.

GROWING THE COTTON

Cotton plant’s leaves resemble maple leaves and flowers look very much like pink mallow flowers that grow in swampy areas. They are relatives and belong in the same plant family.

Cotton is grown in about 80 countries, in a band that stretches around the world between latitudes 45 North to 30 South. For a good crop of cotton a long, sunny growing season with at least 160 frost-free days and ample water are required. Well drained, crumbly soils that can keep moisture well are the best. In most regions extra water must be supplied by irrigation. Because of it’s long growing season it is best to plant early but not before the sun has warmed the soil enough.

Seedlings appear about 5 days after planting the seeds. Weeds have to be removed because they compete with seedlings for water, light and minerals and also encourage pests and diseases. The first flower buds appear after 5-6 weeks, and in another 3-5 weeks these buds become flowers.
Each flower falls after only 3 days leaving behind a small seed pot, known as the boll. Children in cotton-growing areas in the South sometimes sing this song about the flowers:
First day white, next day red,
third day from my birth – I’m dead.
Each boll contains about 30 seeds, and up to 500 000 fibres of cotton. Each fibre grows its full length in 3 weeks and for the following 4-7 weeks each fiber gets thicker as layers of cellulose build up the cell walls. While this is happening the boll matures and in about 10 weeks after flowering it splits open. The raw cotton fibres burst out to dry in the sun. As they lose water and die, each fibre collapses into what looks like a twisted ribbon. Now is time for harvesting. Most cotton is hand-picked. This is the best method of obtaining fully grown cotton because unwanted material, called “trash”, like leaves and the remains of the boll are left behind. Also the cotton that is too young to harvest is left for a second and third picking. A crop can be picked over a period of two months as the bolls ripen. Countries that are wealthy and where the land is flat enough usually pick cotton with machines – cotton harvesters.

GLOBAL COTTON – VATIETIES – PLANTING AND HARVESTING PERIODS

SNo Country Planting Period Harvesting Staple-mm Mike Variety
1 AFGHANISTAN APRIL-MAY OCT-DEC 26-28 4.0 ACALA
2 ARGENTINA SEPT-OCT FEB-JUNE 24-28 3.9-4.1 TOBA
3 AUSTRALIA SEPT-NOV MAR-JUNE 24-29 3.2-4.9 DPL
4 BRAZIL OCT-NOV MAR-JUNE 26-28 3.2-4.0 IAC
BRAZIL PERENNIAL 32-35 3.2-4.8 MOCO
5 BURKIN JUNE-JULY NOV-DEC 25-28 3.6-4.8 ALLEN
6 CAMERRON JUNE NOV-DEC 25-28 3.8-4.3 ALLEN
7 CENTRAL AFRICA JUN-JULY NOV-DEC 25-28 3.8-4.2 ALLEN
8 CHAD JUNE NOV-DEC 25-28 3.8-4.4 ALLEN
9 CHINA APRIL-JUNE SEP-OCT 22-28 3.5-4.7 SHANDONG
XINJIANG
MNH-93
10 COTED IVORIE JUN-AUG OCT-JAN 24-28 2.6-4.6 ALLEN
11 EGYPT MARCH SEP-OCT 31-40 3.24.6 GIZA
12 GREECE APRIL SEPT-OCT 26-28 3.8-4.2 4S
13 INDIA APRIL-NOV SEP-NOV 16-38 2.8-7.9 SEPARATE LIST
INDIA SEPT-NOV FEB-APR
14 IRAN MAR-APR SEP-NOV 26-28 3.9-4.5 COKER
15 ISRAEL APRIL SEP-OCT 26-37 3.5-4.3 ACALA
PIMA
16 KAZAKSTAN APR-MAY SEP-NOV
17 MALI JUN-JUL OCT-NOV 26-27 3.7-4.5 BJA
18 MEXICO MAR-JUNE AUG-DEC 26-29 3.5-4.5 DELTAPINE
19 MOZAMBIQUE NOV-DEC APR-MAY 25-29 3.6-4.2 A637
20 NIGARIA JUL-AUG DEC-FEB 24-26 2.5-4.0 SAMARU
21 PAKISTAN APR-JUN SEP-DEC 12-33 3.5-6.0
22 PARAGUAY OCT-DEC MAR-APR 26-28 3.3-4.2 EMPIRE
23 PERU JUL-NOV FEB-AUG 29-.8 3.3-4.2 TANGUIS
PIMA
24 SPAIN APR-MAY SEP-NOV 25-28 3.3-4.9 CAROLINA
25 SUDAN AUG JUN-APR 27-E0 3.8-4.2 BARAKAT
ACALA
26 SYRIA APR-MAY SEP-NOV 25-29 3.8-4.8 ALEPPO
27 TAZIKSTAN APR-MAY SEP-NOV
28 TOGO JUN-JUL NOV-DEC 28-29 4.3-5.5 ALLEN
29 TURKMENISTAN APR-MAY SEP-NOV 24-29 3.5-5.5 DELTAPINE
COKER
30 TURKEY APR-MAY SEP-NOV 24-28 3.5-5.5 DELTAPINE
31 UGANDA APR-JUN NOV-FEB 26-28 3.3-4.8 BAP-SATU
32 UZBEKISTAN APR-MAY SEP-NOV 24-41 3.5-4.7
33 USA APR-MAY SEP-DEC 26-40 3.8-4.5 VARIETIES
28-30 3.0-4.0 ACALA 151T
28-29 3.8-4.6 DELTAPINENC
25-28 3.2-4.6 PAYMASTER 280
27-28 3.7-4.7 STONOVILLE ST
35-40 3.5-4.5 PIMA S7
34 YEMEN AUG-SEP JUN-APR 36-40 3.5-4.9 K4

COTTON AND YARN QUALITY CO-RELATION:

Instead of buying any cotton available at lowest price, spinning it to produce yarn of highest count possible and selling Yam at any market in random, it is advisable to locate a good market where Yarn can be sold at highest price and select a Cotton which has characteristics to spin Yarn of desired specifications for that market.

ESSENTIAL CHARACTERISTICS of cotton quality and characteristics of Yarn quality of Yarn are given from detailed experimental investigations. Some of the important conclusions which help to find co-relation between Yarn quality and Cotton quality are given below

  • STAPLE LENGTH: If the length of fiber is longer, it can be spun into finer counts of Yarn which can fetch higher prices. It also gives stronger Yarn.
  • STRENGTH : Stronger fibers give stronger Yarns. Further, processing speeds can be higher so that higher productivity can be achieved with less end-breakages.
  • FIBER FINENESS: Finer Fibers produce finer count of Yarn and it also helps to produce stronger Yarns.
  • FIBER MATURITY : Mature fibers give better evenness of Yarn. There will be less end – breakages . Better dyes’ absorbency is additional benefit.
  • UNIFORMITY RATIO: If the ratio is higher. Yam is more even and there is reduced end-breakages.
  • ELONGATION :A better value of elongation will help to reduce end-breakages in spinning and hence higher productivity with low wastage of raw material.
  • NON-LINT CONTENT: Low percentage of Trash will reduce the process waste in Blow Room and cards. There will be less chances of Yarn defects.
  • SUGAR CONTENT: Higher Sugar Content will .create stickiness of fiber and create processing problem of licking in the machines.
  • MOISTURE CONTENT : If Moisture Content is more than standard value of 8.5%, there will be more invisable loss. If moisture is less than 8.5%, then there will be tendency for brittleness of fiber resulting in frequent Yarn breakages.
  • FEEL : If the feel of the Cotton is smooth, it will be produce more smooth yarn which has potential for weaving better fabric.
  • CLASS : Cotton having better grade in classing will produce less process waste and Yarn will have better appearance.
  • GREY VALUE: Rd. of calorimeter is higher it means it can reflect light better and Yam will give better appearance.
  • YELLOWNESS : When value of yellowness is more, the grade becomes lower and lower grades produce weaker & inferior yarns.
  • NEPPINESS : Neppiness may be due to entanglement of fibers in ginning process or immature fibers. Entangled fibers can be sorted out by careful processing But, Neps due to immature fiber will stay on in the end product and cause the level of Yarndefects to go higher.

An analysis can be made of Yarn properties which can be directly attributed to cotton quality.

1. YARN COUNT: Higher Count of Yarn .can be produced by longer, finer and stronger fibers.

2. C.V. of COUNT: Higher Fiber Uniformity and lower level of short fiber percentage will be beneficial to keep C.V.(Co-efficient of Variation) at lowest.

3. TENSILE STRENGTH : This is directly related to fiber strength. Longer Length of fiber will also help to produce stronger yarns.

4. C.V. OF STRENGTH : is directly related CV of fiber strength.

5. ELONGATION : Yam elongation will be beneficial for weaving efficiently. Fiber with better elongation have positive co-relation with Yarn elongation.

6. C.V. OF ELONGATION: C.V. of Yarn Elongation can be low when C.V. of fiber elongation is also low.

7. MARS VARIATION : This property directly related to fiber maturity and fiber uniformity.

8. HAIRINESS : is due to faster processing speeds and high level of very short fibers,

9. DYEING QUALITY : will defend on Evenness of Yarn and marketing of cotton fibers.

10. BRIGHTNESS : Yarn will give brighter appearance if cotton grade is higher.

COTTON QUALITY SPECIFICATIONS:

The most important fiber quality is Fiber Length

Length

Staple
classification
Length mm Length inches Spinning Count
Short Less than 24 15/16 -1 Coarse Below 20
Medium 24- 28 1.1/132-1.3/32 Medium Count 20s-34s
Long 28 -34 1.3/32 -1.3/8 Fine Count 34s – 60s
Extra Long 34- 40 1.3/8 -1.9/16 Superfine Count 80s – 140s

Notes:

  • Spinning Count does not depend on staple length only. It also depends on fineness and processing machinery.
  • Length is measured by hand stapling or Fibrograph for 2.5% Span Length
  • 2.5%SL (Spun Length) means at least 2.5% of total fibers have length exceeding this value.
  • 50% SL means at least 50% of total fibers have length exceeding this value.

LENGTH UNIFORMITY

Length Uniformity is Calculated by 50SL x 100 / 2.5 SL

Significance of UR (Uniformity Radio) is given below:

UR% Classification 50-55
Very Good 45-50 Good 40-45
Satisfactory 35-40
Poor Below 30 Unusable
M= 50% SL
UHM SL – Average value of length of Longest of 50% of Fibers
UI Uniformity Index
UI M/UHM

Interpretation of Uniformity Index

U.INDEX CLASSIFICATION UHM CLASSIFICATION
Below 77 Very low Below 0.99 Short
77-99 Low 0.99-1.10 Medium
80-82 Average 1.11-1.26 Long
83-85 High Above 1.26 Extra Long
Above 85 Very High

Now Uniformity is measured by HVI

Fiber Strength

Fiber Strength, next important quality is tested using Pressley instrument and the value is given in Thousands of Pounds per Square inch. (1000 psi) For better accuracy, Stelometer is used and results are given in grams / Tex.

Lately, strength is measured in HVI (High Value Instrument) and result is given in terms of grams/tex.

Interpretation of Strength value is given below

G/tex Classification
Below 23 Weak
24-25 Medium
26-28 Average
29-30 Strong
Above 31 Very Strong

Strength is essential for stronger yarns and higher processing speeds.

  • Fiber Fineness Fiber Fineness and maturity are tested in a conjunction using Micronaire Instrument.
  • Finer Fibers give stronger yarns but amenable for more neppiness of Yarn due to lower maturity.
  • Micronaire values vary from 2.6 to 7.5 in various varieties.

FINENESS AND MATURITY

Usually Micronaire value is referred to evaluate fineness of Cotton and its suitability for spinning particular count of Yarn. As the value is a combined result of fineness and maturity of Cotton fiber, it cannot be interpreted, property for ascertaining its spinning Value. This value should be taken in conjunction with standard value of Calibrated Cotton value.

The following table will explain that micronaire value goes up along with maturity but declines with thickness of fiber. An Egyptian variety of Cotton, three samples of High maturity. Low maturity and Medium maturity were taken and tested. Test results are given below,

Maturity Micronaire Perimeter Maturity Maturity Ratio
High 4.3 52.9 85.1 1.02
Medium 4.0 54.4 80.1 0.96
Low 3.9 54.7 79.3 0.95

Here, Micronaire Value of 4.3 is higher than 3.9 of low maturity cotton Another Greek Cotton was tested and results are give below

High 3.8 57.0 75.1 0.88
Medium 3.5 54.9 70.7 0.84
Low 3.2 55.2 65.8 0.80

Micronaire Value of 3.8 is higher than 3.2 of low maturity cotton. Another American Cotton was tested and results are as follows

High 4.1 64.4 75.9 0.87
Medium 3.4 62.1 68.0 0.80
Low 2.7 59.8 56.1 0.67

Hence, it is essential to know what Micronaire value is good for each variety of Cotton.

Maturity Ratio Classification
1.00 and above Very Mature
0.95 – 1.0 Above Average
0.85 – 0.95 Mature
0.80 – 0.85 Below Average
Less than 0.80 immature

COTTON GRADE

Cotton grade is determined by evaluating colour, leaf and ginning preparation. Higher grade cottons provide better yarn appearance and reduced process waste.

Colour is determined by using Nickerson-Hunter Calorimeter. This gives values Rd (Light or Dark) and +b (Yellowness).

AMERICAN UPLAND COTTONS ARE CLASSIFIED
ACCORDING TO GRADES AS GIVEN BELOW

WHITE COLOUR

S.NO GRADE SYMBOL CODE
1 GOOD MIDDLING GM 11
2 STRICT MIDDLING SM 21
3 MIDDLING M 31
4 STRICT LOW MIDDLING SLM 41
5 LOW MIDDLING LM 51
6 STRICT GOOD ORDINARY SGO 61
7 GOOD ORDINARY GO 71
8 BELOW GRADE

Similar grading is done for Light Spotted, Spotted, Tinged and Yellow Stained Cottons. PIMA cottons are graded I to 9

HOW TO BUY COTTON?

COTTON BUYING is the most important function that will contribute to optimum profit of a Spinning Mill.

EVALUATION of cotton quality is generally based more on experience rather than scientific testing of characteristics only.

TIMING of purchase depends on comprehensive knowledge about various factors which affect the prices.

CHOOSING the supplier for reliability of delivery schedules and ability to supply cotton within the prescribed range of various parameters which define the quality of Cotton.

BARGINING for lowest price depends on the buyer’s reputation for prompt payment and accept delivery without dispute irrespective of price fluctuations.

ORGANISING the logistics for transportation of goods and payment for value of goods will improve the benefits arising out of the transaction.

PROFIT depends on producting high quality Yarn to fetch high prices. Influence of quality of raw material is very important in producing quality Yarn. But, quality of yam is a compound effect of quality of raw material, skills of work-force, performance of machines,- process know-how of Technicians and management expertise.

A good spinner is one who produces reasonably priced yarn of acceptable quality from reasonably priced fiber. Buying a high quality, high priced cotton does not necessarily result in high quality Yarn or high profits.

GUIDELINES FOR COTTON CONTRACTS:

Buyer and seller should clearly reach correct understanding on the following factors.

1. Country of Origin, Area of Growth, Variety, Crop year

2. Quality – Based on sample or

Description of grade as per ASTM standard or sample
For grade only and specifying range of staple length,
Range of Micronaire, range of Pressley value, uniformity,
Percentage of short fiber, percentage of non-lint content,
Tolerable level of stickiness

3. Percentage of Sampling at destination

4. Procedure for settling disputes on quality or fulfillment of contract obligations.

5. Responsibility regarding contamination or stickiness.

6. Price in terms of currency, Weight and place of delivery.

7. Shipment periods

8. Certified shipment weights or landing Weights

9. Tolerances for Weights and Specifications

10. Port of Shipment and port of destination, partial shipments allowed or not, transshipment allowed or not, shipments in containers or Break-bulk carriers

11. Specifications regarding age of vessels used for shipment, freight payment in advance or on delivery

12. Responsibility regarding Import & Export duties

13. Terms of Insurance cover

14. Accurate details of Seller, Buyer and Broker

15. Terms of Letter of. Credit regarding bank .negotiation, reimbursement and special conditions, if any

Choose Correct Supplier or Agent:

Apart from ensuring correct terms of Contract, Buyer should ensure that purchase is made from Reliable Supplier or through a Reliable Agent. Some suppliers evade supplies under some pretext if the market goes up. Otherwise, they supply inferior quality Either way buyer suffers.

By establishing long term relationship will reliable Suppliers, Buyers can have satisfaction of getting correct quality, timely deliveries and fair prices.

CHOOSING SUPPLIER:

It is good to establish long term relationship with a few Agents who represent reputed Trading Companies in various Cotton Exporting Countries. They usually give reliable market information on quality, prices and market trends so that buyer can take intelligent decision. As cotton is not a manufactured Commodity, it is good to buy from dependable suppliers, who will ensure supply of correct quality with a variation within acceptable limits at correct price and also deliver on due date.

CHOOSING QUALITY:

In a market with varying market demand situation. Buyers should decide which counts of Yarn to spin. Buyer can call for samples suitable for spinning Yarn counts programmed for production. Many spinners plan to do under-spinning. For Example, cotton suitable for 44s is used for spinning 40s. Some spinners do over-spinning. They buy cotton suitable for 40s and spin 44s count. But, is advisable to spin optimum count to ensure quality and also keep cost of raw material at minimum level as for as possible. Some spinners also buy 2 or more varieties and blend them for optimum spinning. For’ this purpose, a good knowledge to evaluate cotton quality and co-relate with yarn properties of required specifications. Cotton buyer should develop expertise in assessing cotton quality. Machine tests must be done only to confirm manual evaluation.

TAKING RIGHT OPTION:

It is not advisable just to look at price quoted by supplier. Correct costing should be done to work out actual cost when the cotton arrives at Mills. Further lowest price does not always mean highest profit for buying. Profitability may be affected by anyone or more of the following factors.

  • If the trash is higher, more waste will be produced reducing the Yarn out- turn and hence profit.
  • If the uniformity is less, end – breakages will be more reducing productivity and profitability.
  • If grade is poor or more immature fibers are found in cotton, the yarn appearance will be affected and Yarn will fetch lesser price in the market.
  • If the transit period for transport of cotton is longer, then also profitability will be reduced due blocking of funds for a longer period and increased cost of Interest.
  • Rate of Sales Tax varies from State to State. This must be taken in to account.
  • Hence, thorough costing should be worked out before deciding on the quoted pnce onlv

The margin of profit in spinning cotton should be calculated before deciding on The various options available depending on market conditions should be studied.

The factors to be considered for taking options are as follows.

  • Count for which demand is good in market
  • Prices for various counts for which demand exists.
  • Cost of manufacturing various counts.
  • Adequacy of machinery for the selected count.
  • Various varieties of cotton available for spinning the selected count.
  • Profit margin for each count using different varieties.
  • Price quoted by different Agents for same variety of selected cotton.
  • Reliability of supplier for quality and timely delivery.

Cost Consideration:

Apart from the price quoted by the seller, other incidental costs must be taken into consideration before buying.

a) Duration for goods to reach Buyer’s godown from the seller’s Warehouse. If the duration is longer, buyer will incur higher interest charges.

b) Cost of Transportation and taxes.

Resolution of differences

If any discrepancy arises in the quality, weight and delivery periods, sellers should be willing to resolve the differences amicably and quickly. In case the matter is referred to Arbitrator, the award of the Arbitrator must be immediately enforced.

Bench Marks for Easy Reference

It is better if quality bench marks are established for different varieties so that buying decisions are easy for buyers Following standards have been found to be appropriate for Strict Middling Grade Cotton of staple 1.3/32″.

  1. Staple Length ( 2.5% Spun Length) – Minimum 1.08″ or 27.4 mm
  2. Micronaire : Minimum 3.8, Maximum-4.6 Variation within bulk sample should not be more than _ 0.1
  3. Colour : Rd not less than 75 not more than 10
  4. Nep Content: Less than 150 per gram
  5. Strength : More than 30 grams/tex
  6. Length Uniformity Ratio: Not less than 85%
  7. Elongation : More than 8%
  8. Short Fiber Content: Less than 5%
  9. Seed Count Fragments : Less than 15 per grams
    1. Commercial Bench marks can be given as follows:
      1. Price Competitiveness
      2. Price Stability
      3. Easy Availability throughout year
      4. Uniform Classing and Grading system
      5. Even- running Cotton in all Characteristics
      6. Reliable deliveries òr Respect for sanctity of contract.

QUALITY EVALUATION:

The need for quality evaluation is for following purposes

a) To get optimum quality at lowest price.
b) To decide whether cotton bought will can be processed to spin Yarn of desired specifications.
c) To check the quality of sample cotton with quality of delivered cotton.
d) To decide about correct machine settings and speeds for processing the cotton
e) To estimate profitability of purchase decisions.

Knowing the cotton properties is only half the battle for profits. It needs expertise to know how to get best of its value.

Currently popular instrument called HVI gives ready information on various parameters to make correct purchase decisions.

If may not be possible to get all the desired qualities in one variety or one lot of Cotton. In such case, an intelligent decision to select best combination of different varieties or lots to get desired Yam quality is necessary to get optimum yarn quality at optimum cost.

If correct evaluation is made, profits are large. Hence, evaluation of quality is essential for optimum profit making and also make the customers happy with supply of correct quality of Yarn.

Expert classers can manage to achieve reasonable level of correct evaluation. Now, with availability of better instruments, it is better to check qualities to make sure that desired quality of cotton is procured.  These details should give cotton buyer reasonable guidance to make correct evaluation of cotton quality and ensure its suitability for producing required quality of yarn.

QUALITY EVALUATION        CHARACTERISTICS CO-RELATION TO YARN
1. Staple Length Spinning Potential
2. Fiber Strength Yarn strength, less Breakages
3. Fineness   Finer Spinning Potential
4. Maturity Yarn Strength and even ness, better dyeing
5. Non-Lint.content (Trash) Reduced Waste
6, Uniformity Ratio Better productivity and Evenness
7. Elongation Less end Breakages
8, Friction Cohesiveness
9. Class Yarn Appearance
10.Stickiness Spinning problem by lapping & Dyeing quality
11. Grey Value Yarn lustre
12. Yellowness Yarn Appearance
13.Neppiness Yarn neppiness
14. Moisture Content 8.5% moisture content optimum for spinning at 65%

QUALITY TESTING INSTRUMENTS:

Instrument Measurements
Fibrogaph   Length
Pressley Apparatres Fiber Bundle Strength
HV I Instrument Length, Strength, Uniformity, Elongation, Micronaire, Color and Trash
Stelometer Instrument Strength, Elongation
Micronaire Combined test of fineness & maturity
Shirley Trash Analyser Trash Content
Manual Test Class & staple length
Moisture Meter Moisture
Colorimeter Grey value & yellow ness. Brightness
Polarised light Microscope or
Casricaire test
Maturity
Photographic film   Neppiness

clip_image001clip_image002

Digg This
Advertisements

Bedford-cord


PLAIN FACE BEDFORDCORD

Bedford cord is the class of weaves produces the longitudinal warp lines in the cloth with fine sunken lines between.

The Bedford cord named after the town of Bedford in England. It is a heavy fabric with a length wise ribbed weave that reassembled corduroy.

METHOD OF CONSTRUCTION

· At interval pair of ends work in perfectly plain order with the picks, therefore these lifts are first indicated

clip_image002

· The number of ends between the pair of plain end being varied according to the width of cord required.

· The next stage is consist of inserting marks (which indicating warp float) on the first and second picks of alternate cords and on the third and fourth picks of the other cords.

clip_image004

· The object of arranging the marks of the cord ends in alternate order is chiefly to equalize the lift of the ends.

· The designs are completed by inserting plain weave on the cord ends, which join with the plain working of the pair of ends.

clip_image006

STRUCTURE DETAIL

· The cord ends float over three picks and under one while the picks float in pairs on the back of one cord and interweave in plain order in the next cord.

 

DRAFTING AND DENTING

· The usual order of drafting is shown here

· The plain ends are being drawn on the healds of front and accordingly the lifting plan is maid.

clip_image008

· In order to fully develop the sunken lines the plain should be separated by the slits of the reed

clip_image010

· In some cases however the plain ends are dented accordingly to the type of fineness required.

clip_image012

· Sometimes the plain ends are woven two per slit and cord ends are three or four per slit. The number of ends in the width of a cord has some influence upon the order of denting.

WADDED BEDFORD CORD

This structure contain thick wadding or padding ends which lie between the rib face cloth and the weft floats on the undersides the arrangement to give grater prominence to the cord.

METHOD TO INTRODUCE WADDING ENDS

· First we decide the place at which the wadding ends are introduced

clip_image014

· The wadding ends are raised where the picks floats at the back shown in design and are left down where the picks interweave in plain order.

clip_image016

· In order of interlacement of the picks and position of warps is shown here

DRAFTING AND DENTING

· Here the drawing (drafting) is done in same maner as before only after plain order healdshafts. The wadding ends are drawn and then the cord ends.

clip_image018

· Here while denting is done, like 2 ends per slit the wadding ends being dented extra

clip_image020

· The number of wadding ends to each cord may be varied according to requirement.

OTHER:

· The design may be arranged with an odd number of each (not including the wadding ends) to each cord but it is then necessary to reserve the marks of an alternate pairs of the plain ends in order that the plain weave will join correctly.

clip_image021 clip_image023

SUITABLE WEAVING CONDITION

· Face warp= 30’s Cotton, 108 Ends per inch

· Wadding warp= 2/20’s cotton

· Weft = 36’s cotton, 84 picks per inch

TWILL FACED BEDFORD CORD

· It is an another modification of Bedford cord structure consist of the using warp twill instead of plain weave for the picks which inter weave on the face of the cord stripes.

· Thus the warp being brought more prominently on surface.

· The construction is same like a plain face but the introduction of twill weave in place of plain is take place.

clip_image025

 

WHY CORDS ARE FORMED?

· The structure is formed due to the occurrence of force variations in structure.

· The plain order is highly compact structure here end 6-7 will force the yarn downward due to the plain order.

· And the other region contain plain or twill order with the warp floats which will not force but allow the other ends to move up.

· And this variation of force form the force forms the cord.

 

 

BEDFORD CORD ARRANGED WITH ALTERNATE PICKS

· Bedford cord are also made with alternate picks floating at the back, in which case the pairs of plain ends require to be indicated in the reverse order.

· Here we take an example of 10 end wide cord first the marks of the pairs of plain ends are indicated

clip_image027

· Then the marks which cut with plain marks are inserted on the alternate horizontal spaces.

clip_image029

· Afterwards plain weave is inserted on the blank horizontal spaces of the cords as indicated

clip_image031

· But in this case plain does not join perfectly with the plain marks of the pair of ends

· Wadding ends also may introduce according to the requirement, this wadding ends are shown raised over the picks which floats at the back.

clip_image033

APPLICATION:

· Fabric produced with these weave may be made in medium weight cotton or spun rayon fabrics for Dress wear, Sports-wear and ornamental trimming.

· In heavier qualities, It is suitable for Soft furnishing when produced with cotton yarns or for Suiting when made up of worsted yarns.

· Also used for shirting, coating, upholstery, uniforms etc.

Digg This

Historical Sketch Of The Textiles


( Originally Published Early 1900’s )

No one can tell when man first learned how to spin and weave textiles. That no great degree of civilization is prerequisite is evident when we see every savage tribe of the present making some kind of woven fabric. In any case, the oldest histories give us glimpses of men spinning, weaving, and knitting.

Linen.-Flax has been cultivated in Asia Minor for its linen fiber for more than four thousand years. Linen cloth, linen twine, and linen rope served man before iron and steel were utilized. People who lived in the stone age, the period when their implements were made of stone instead of metal, knew how to make flax or linen fabrics, remnants of which have been discovered in caves and in their buried cities. As is well known, linen cloth was the fashionable fabric of ancient Bible times. “Fine linen” was a mark of honor accorded only to the high and mighty. Mummies buried thousands of years ago in Egypt have been uncovered recently, and the coverings have been found to be linen cloth, made from a variety of flax slightly different from that now commonly grown.

For many hundreds of years Egypt was the greatest linenproducing country in the world. It was not until about a hundred years before Columbus discovered America that other countries were able to produce more than Egypt. Then every country in Europe began to cultivate flax, and until the latter part of the eighteenth century, when a number of inventions made cotton fabrics cheap, linen was the most generally used textile. With the coming of cheap cotton, linen fell back into second place. Later it had to give place to wool also, wherefore it now occupies third place among the textiles used for clothing. In fact if one is to consider jute also, linen comes fourth.

Wool.-Sheep’s wool and goat’s hair have also long been used as textile fibers, and, of course, the skins from these animals have been used for clothing and tents for a still longer time. Sheep have been raised in practically every country, and the fiber is easy to manipulate and to work into textile products. The ancient Romans were skillful in spinning and weaving wool, and from them the people of northern Europe learned the art. About four hundred years after the birth of Christ (c. 400 A.D.) Roman soldiers in Great Britain started a wool-weaving factory at the British town of Winchester to supply themselves with clothing. From this factory the native inhabitants of Great Britain learned the value of wool, and began to spin and weave it for themselves. Later the wool of England became famous as an excellent product and was much demanded by other countries in Europe. Sheep raising succeeded better than the textile arts in England, however, in the early days; hence other countries bought its raw wool rather than the English wool fabrics. Several monarchs of England did their utmost to encourage the manufacture of wool. This manufacture was finally put upon a successful commercial basis by some Flemish immigrants who had fled into England because of religious persecution. Both wool workers and merchants came to London in large numbers during the reign of Henry II. Guilds were formed and London was given the monopoly of exporting English woolen cloths. From these beginnings several hundreds of years ago, London came to be, and is yet, the world’s greatest wool market both for raw wool and wool cloth.

It is interesting to note that during the hundreds of years that man has raised sheep, the breeds have been slowly but remarkably developed. First the Romans, later the Arabian Mohammedans-or Moors, as they were calledand finally the Spaniards, evolved the wonderful breed of fine wool-producing sheep now known as merinos. Nearly all the finer wool now produced comes from sheep descended from these Spanish merinos.

Cotton.-Cotton was grown and made into cloth in India fully six hundred years before Christ. The textile arts were developed to an advanced point very early by the Hindoos. If one may believe the accounts of the fineness, strength, beauty, and lightness of the East Indian gossamers, the products of their hand looms, made long centuries ago, have never been equaled by any modern fabric.

Cotton was also known to the highly advanced South American Indians. Samples of good cotton cloths have been found in their most ancient tombs. Columbus found the Indians of the West Indies wearing cotton, and Cortez and Pizarro often saw it in use.

Cotton was known to the Greeks as “tree wool” and was fancifully described in some of their ancient books. It did not reach western Europe until about 900 A. n., when it was brought westward from Arabia by the conquering Moors. They introduced it into Spain, whence it gradually spread over the rest of Europe. There was some manufacture of cotton in northern Italy as early as the sixteenth century. From there it was communicated to the Netherlands. About the beginning of the seventeenth century there was religious trouble in Netherlands and Flanders. Some of the Flemish cotton manufacturers, spinners, and weavers were involved in these religious quarrels, and had to flee for their lives, as did the wool workers who came over from these countries to London. The cotton workers fled into England and settled in Lancashire where they made a new beginning in cotton manufacture and succeeded from the start. With this hopeful beginning in the seventeenth century, Lancashire came to be the greatest cottonspinning and weaving locality in the world. By 1641 the industry was well established in the homes of the people about the city of Manchester.

After the sixteenth century there was a steady and growing import of cotton goods from India into all parts of Europe; but about one hundred and twenty-five years ago Europe began to produce more than she needed and more than India had produced. By means of this East Indian trade in cotton and in many other goods, such as spices, silks, jewelry, and so on, European traders and merchants, particularly those in the East India Company, amassed great fortunes. For a time the English trade in Indian goods was a monopoly controlled by the East India Company and sanctioned by the king of England.

England’s rise to supremacy in cotton manufacture.At the time of our American Revolutionary War, England had so gained in manufacturing ability that she had become a strong competitor for the world’s textile trade. It was partly because of England’s policy of forcing the American colonies to buy her manufactured goods that the War of Independence broke out. In 1656 the English government had prohibited the American colonies from importing raw materials to manufacture into cloth. The law made bad feeling even at that time, especially in Massachusetts where, on the one hand, it acted as a stimulus to home manufacturing and, on the other hand, led to smuggling in foreign materials without paying the English tax. But the same policy was carried out by England at home also. It was thought perfectly legitimate to attempt to force her own people to buy English goods. In Scotland in 1775 there was formed a society for discouraging Scotch and English women from wearing cotton dress goods and robes made in India, urging in preference the calicoes and lawns of Glasgow and Paisley, although the raw cotton in these British products came from India. In addition to any help that may have been received from following such restrictive measures, the natural advantages of England, such as climate, cheap power, and easy shipping facilities by ocean on all sides, caused England’s textile industry to grow rapidly.

Progress in Cotton Production.-During the last hundred years the United States has forged to the front as a producer of both raw and manufactured cottons. At present the annual cotton crop is not far from 15,000,000 bales of nearly 500 pounds each. In the manufacture of cotton the United States is closely rivaling England, though England still has the lead. Within the last forty years Germany has advanced to third place in the manufacture of cotton.

The history of the production of raw cotton during the last twenty-five years records notable extension to new territory, as, for example, into China, Japan, the East Indies, Mexico, South America, and several parts of Africa. With increase of acreage there has also come the application of scientific agriculture to cotton production in the southern states. By means of proper selection of seed, introduction of new and improved varieties, better preparation of the soil, and wiser management of the growing crop, the total product has been materially increased. In many cases these improvements have resulted in the production of over twice as much cotton to the acre as was formerly raised.

History of silk.-Silk culture had its beginning in China, how long ago no one knows. There are records that seem to show that it was an important industry as early as 3000 B. c. There is a legend that silk culture was introduced by a Chinese queen, Si-Ling-Chi, from some country to the southwest, and that she herself raised the worms, reeled the threads,, and taught the people to do the same. She is now known among the Chinese as the “Goddess of the Silk Worms.”

Silk production was introduced into Korea and Japan about 200 B.C. Later it spread to India and Persia, although the Chinese government attempted to keep all silk production to itself. To ship silkworm eggs out of the country meant capital punishment. It was from India and Persia that Europe first learned of silk. To a certain extent the new material was used in Roman times by the emperors and the women of the court, but it was not until about the tenth century that it became known generally over western Europe. Much of it came into use at first for church embroideries and royal robes, especially in the form of a silken fabric called sammet, produced in Arabia. Other silk fabrics introduced into Europe during the Middle Ages were known as ciclatoun, cendol, and sarcenet. Satins, velvets, and brocades were introduced in the latter part of the Middle Ages, all from the Orient.

Arabia was for a long time the connecting link between the Orient and the West, and from Arabia the Europeans got silk embroidery, gold brocade, silken curtains and mantles, and, by the fourteenth century, taffeta, which originally came from Persia.

The production of raw silk in Europe was begun in Italy before the middle of the twelfth century, and silkworms were raised in Spain by the Mohammedan Moors certainly as early as the eighth century. At one time the business was encouraged by the popes of the Roman Catholic Church, and later by the kings of France. Under such conditions Tours and Lyons in France became prominent silk-producing centers. By the seventeenth century, France supplied a large proportion of the silk goods used in the western world, a service in which she has led all other countries for most of the time since then. At present, Italy produces more raw silk than France, but France produces more of the manufactured product.

Silk culture in America.-Shortly after the settlement of America experiments were tried in raising the silkworm here. The first attempt was made in Virginia in 1622 upon the advice of the king of England, but the result was an utter failure. Later small amounts of raw silk were produced in Georgia, Connecticut, Pennsylvania, New Jersey, and Rhode Island. Connecticut was the least unsuccessful. During the Revolutionary War the industry died out and was not revived again until 1826. Beginning with that date and continuing for ten years there was great progress in silk production. Several societies of growers were formed, books published, new machinery invented, and in some states public funds were raised for the promotion and study of the industry. The United States Government published a document intended to be used as a manual of instruction for silk growers.

The silk craze of the thirties.-Previous to 1836, silkworms had been fed and raised on the common white mulberry leaves, but about this date someone introduced plants of the Chinese mulberry known as the morus multicaulis which, it was claimed, had some special properties and values for silk-growing purposes. Immediately all the silk growers in the country desired the Chinese mulberry. The new plant was so hard to get that a craze developed in which the price for the plants rose to fabulous sums, small cuttings selling for almost their weight in gold. Acres and acres were planted with Chinese mulberry trees, and great fortunes in silk production in this country seemed near at hand.

In 1837, however, a severe financial panic broke over the entire country, closing nearly every bank and driving great numbers of business men into failure and bankruptcy. Money became scarce. Those who had debts to pay found it difficult to raise the necessary amounts. This panic of 1837 hit the silk and mulberry industries hard. Chinese mulberry plants so declined in value that they could be had for ten cents per hundred. Thousands of persons were ruined in this crash which lasted throughout the years of 1837 and 1838. Silk growing naturally received a terrible set-back, which was made worse by the severe winter of 1839, which killed nearly all the Chinese mulberry trees still to be found in the country. For several years no more silk was grown in the United States.

Many years passed before there came any revival of interest in this country in growing silkworms. In the meantime, manufactories sprang up here and there in the East, which imported from Europe all their raw silk. By 1860 there were no less than sixty-seven factories. There had grown up an importing trade, and business had ceased to look to domestic sources for supplies of raw silk.

The California silk craze.-In 1861 a Frenchman named L. Prevost began raising silk near San Jose in California. Prevost was something of a promoter and he soon interested a considerable number of California people in the industry. His plan, however, was to raise the silkworm mainly for the eggs rather than the silk fiber. The eggs were to be sold to French and other European silk producers. The California State Agricultural Society became interested in Prevost’s scheme and aided in its advertising, and the state legislature passed a law offering a bounty to silk producers. But Prevost was more successful in promoting the idea than in keeping the venture going. What had developed into a good-sized silk-culture craze in California quickly collapsed when the would-be growers found that the silkworms required an immense amount of care, that they were subject to a number of destructive diseases, and that even the California winters were too severe for the worms when kept out of doors.

Recent attempts to produce raw silk.-Attempts to raise silkworms were made in Kansas in the boom days of that state, in the later seventies, but the droughts of the eighties stopped the silk culture there. About 1878 the Department of Agriculture in Washington became interested in silk culture, and in the years that followed made considerable effort to interest the people of various sections of the country, especially the South, in growing silkworms. By 1883 regular annual appropriations of money were made for the Department that it might study and promote silk growing. A reeling institution, or filature, was established at Washington, and cocoons were purchased by the government from all growers. Silk growing was revived in Kansas and California and extended into Louisiana and, later, in the nineties, to Utah.

Interest in silk culture on the part of the Department of Agriculture slackened in 1890, and it was not until 1901 that another effort was made to introduce silk growing. This time it was planned to start the industry among the southern negroes of the poorer classes. But even this scheme has not been found successful.

The coming of oriental silks into American markets.Since the bursting of the morus multicaulis silk-growing boom of 1830 and the Prevost craze in California in 1860, and during the time of the more recent experiments just referred to, certain new factors have crept into the silk situation which at present seem to preclude for a long time to come the possibility of making silk growing profitable in this country. In 1854, Commodore Perry of the United States Navy sailed into the ports of Japan and made possible by national treaties the opening of trade with a country which up to that time had held itself aloof from all the rest of the world. It happened that Japan was a great producer of raw silk, which became henceforth one of its principal articles of export. Some years later, China, the greatest silk-producing country, commenced commercial relations with the rest of the world. From these two countries there poured into Europe and the United States a stream of raw silk that speedily reduced the market prices of this commodity from nine and ten dollars to three and four dollars a pound. Japan and China were full of men and women, who, although working for daily wages of some eight to fifteen cents, were nevertheless expert in the care of silkworms. Against such conditions of cheap production the United States could do nothing. Even France lost ground, and today silk culture there is standing still, despite the help of French government bounties. In Europe, only Italy, with her cheap labor and excellent facilities for producing what is pronounced to be the best raw silk in the world, has continued uninterruptedly to cultivate the silkworm.

As soon as the Japanese and Chinese markets were opened to the world, many of the largest manufacturers in this country, as well as in France and Germany, established buying agencies in the midst of the raw-silk-producing areas. It was soon found that there was much waste of energy and of material in the ancient methods employed by both Chinese and Japanese in reeling the silk. This was remedied, so far as certain individual companies were concerned, by starting on their own account reeling factories, called filatures, and by training the native workers in methods of using the improved machinery and methods installed. Several American silk manufacturers now own filatures at Shanghai and Canton, the principal silk markets of China. More recently, Japan has started experiment stations and inspection systems throughout her silk-growing areas, aiming at improving the product to meet the demands of the markets of the United States and Europe.

Industrial Revolution – Timeline of Textile Machinery


Several inventions in textile machinery occurred in a relatively short time period during the industrial revolution.

  • 1733 Flying shuttle invented by John Kay – an improvement to looms that enabled weavers to weave faster.
  • 1742 Cotton mills were first opened in England.
  • 1764 Spinning jenny invented by James Hargreaves – the first machine to improve upon the spinning wheel.
  • 1764 Water frame invented by Richard Arkwright – the first powered textile machine.
  • 1769Arkwright patented the water frame.
  • 1770Hargreaves patented the Spinning Jenny.
  • 1773The first all-cotton textiles were produced in factories.
  • 1779Crompton invented the spinning mule that allowed for greater control over the weaving process
  • 1785Cartwright patented the power loom. It was improved upon by William Horrocks, known for his invention of the variable speed batton in 1813.
  • 1787Cotton goods production had increased 10 fold since 1770.
  • 1789 Samuel Slater brought textile machinery design to the US.
  • 1790Arkwright built the first steam powered textile factory in Nottingham, England.
  • 1792Eli Whitney invented the cotton gin – a machine that automated the separation of cottonseed from the short-staple cotton fiber.
  • 1804 Joseph Marie Jacquard invented the Jacquard Loom that weaved complex designs. Jacquard invented a way of automatically controlling the warp and weft threads on a silk loom by recording patterns of holes in a string of cards*.
  • 1813 William Horrocks invented the variable speed batton (for an improved power loom).
  • 1856William Perkin invented the first synthetic dye.