Maheshwari Trading Company

Raw cotton & its quality

Cotton is a natural fibre of vegetable origin, like linen, jute or hemp. Mostly composed of cellulose (a carbohydrate plant substance) and formed by twisted, ribbon-like shaped fibres, cotton is the fruit of a shrubby plant commonly referred to as the "cotton plant".

The plant, growing up to 10 metres high in the wild, has been domesticated to range between 1 to 2 metres under commercial cultivation in order to facilitate picking. It thrives in dry tropical and subtropical areas.

Although cotton is widely planted in both hemispheres, it remains a sun-loving plant highly vulnerable to freezing temperatures. Cotton is crucially important to several developing countries.

Out of fifty species of cotton plants within the world only four are domestically cultivated for their fibres. The most commonly cultivated species of cotton in the world include

  • Gossypium hirsutum (origin from Mexico)
  • Gossypium barbadense (origin from Peru)
  • Gossypium arboreum and (origin from Indo-Pakistan)
  • Gossypium herbaceum (origin from southern Africa)

The quality of the cotton fibre is determined by three factors, namely, the Colour of ginned cotton, Purity (the absence of foreign matter) and quality of the ginning process, and the Length of fibres.

The colour of cotton ranges from white to yellowish and is classed into the groups "White", "Light Spotted", "Spotted Tinged" and "Yellow Stained", in descending order of quality.

Cotton Quality Specifications

1. Staple Length
The most important fibre quality is Fibre 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 Fibro graph for 2.5% span length.
  • 2.5% SL (Spun Length) means at least 2.5% of total fibres have length exceeding this value.
  • 50% SL means at least 50% of total fibres have length exceeding this value
2. Uniformity Ratio
Length uniformity is calculated by 50 SL × 100 / 2.5 SL
UR% Classification
50-55 = Very Good, 45-50 = Good, 40-45 = Satisfactory,
35-40 = Poor, Below 30 = Unusable

3. Fibre Strength
Fibre strength is tested using Pressley instrument and the value is given in thousands of pounds per square inch (1,000 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 making stronger yarns and higher processing speeds.
  •  Fibre fineness and maturity are tested in a conjunction using Micronaire instrument.
  •  Finer fibres give stronger yarns but amenable for more neppiness of yarn due to lower maturity.
4. Micronaire for fineness and maturity
Usually Micronaire value is referred to evaluate fineness of cotton and its suitability for spinning particular count of yarn.
Micronaire values vary from 2.6 to 7.5 in various varieties.
5. Cotton Grade
Evaluating colours, leaf content and ginning preparation determines cotton grade. Higher-grade cottons provide better yarn appearance and reduced process waste.

VARIETIES OF RAW COTTON IN INDIA
The following are the main varieties of raw cotton grown in India.

Sr. No

Variety

States

States Length

Micronaire

Strength

Spinning Count

Comparable Foreign Growth

(mm)

Inches

Value

G/Tex (lCC)

GPT (HVn)

PSI

1

Bengal Deshi

Punjab/Haryana/Rajasthan

15-18

<13-16"

6.0-8.0

15

19

57000

45,65, Surgical Cotton & Mattresses

Not Compared/None

2

V-797

Gujarat

22-24

7/8"

4.9-5.6

16-17

22

62000

Ne 245

None

3

Jayadhar

Karnataka

22-24

7/8"

4.0-5.0

17-18

23

65000

Ne 245

U.S MOT,Pakistan Afzal

4

Y-1

Maharashtra/Madhya Pradesh

23-25

<1"

3.5-4.9

18-20

24

70000

Ne 245,265

U.S MOT, Pakistan Afzal

5

J-34 Saw Ginned

Punjab/Haryana/Rajasthan

24-26

51"+

3.5-4.9

19-21

26

78000

Ne 265,305

U.S MOT,Pakistan Afzal/1467

6

NHH-44

Maharashtra

24-26

1"+

3.5-4.9

19-20

25

76000

Ne 245,265,305

U.S MOT, Pakistan Afzal/1467

7

L.R.A

Maharashtra/Tamil Nadu/Karnataka/Madhya Pradesh/Andhra Pradesh

25-27

1"+

3.5-4.9

19-21

25

77000

Ne 265,305,365

U.S MOT,Pakistan Afzal/146

8

H-4/MECH1

Maharashtra/Madhya Pradesh/Andhra Pradesh

27 -29

1-3/32"

3.5-4.9

20-22

27

80000

Ne 405,445

W. African, BraziIian, T anzanian, Paraguan, Argentine

9

Sankar-6

Gujarat

27.5-29.5;

1-1/8"

3.5-4.9

21-23

28

88000

Ne 445,505,555

U.S. Fibre Max / Acala, W. African, Australian, Brazilian, Tanzanian, Syrian

10

Bunny / Brahma

Maharashtra/Madhya Pradesh/Andhra Pradesh/Karnataka

29-32

1-5/32"to 1-1/4"

3.5-4.5

22-24

29

88000+

Ne 505,555,605

U.S. SJV Acala, Egyptian Giza 86/ Giza 89, Sudanese Barakat, Chinese 229

11

MCU-5

Maharashtra, Andhra Pradesh, Tamil Nadu, Orissa

32-34

1-1/4"+

3.2-3.7

23-25

30

92000

Ne 605,705,805

U.S. Ultima RG,Egyptian Giza861, Giza 89,Sudanese Barakat

12

DCH-32

Madhya Pradesh, Karnataka, Tamil Nadu

34-36

1-3/8"

2.8-3.3

24-29

32

97000+

Ne 905,1005

U.S. Pima, Egyptian Giza 88/Giza 70, Sudanese Barakat,Chinese 146,GIS ELS, Australian Pima,lsraeli Pima.

13

Suvin

Tamil Nadu

38-40

1-7/16"+

2.9-3.2

30-32

38

115000

Ne 1005

Egyptian Giza 45.

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