Jute Fiber Production | Defect | Grading

Jute fiber is the 2^nd natural fiber in the world production of textile fibers after cotton. It is known as pat, Kosta, Nalita, and Bimli.

Why jute fiber is called composite fiber?

Jute fiber is called composite fiber because many ultimate fibers are cemented together by lignin and build along the fiber. Because:

1. Natural Blend: It’s composed of both cellulose and lignin. That makes it a natural composite material.
2. Structural Strength: Jute fiber has a fibrous structure that provides strength and durability, akin to composite materials.
3. Versatile Applications: Jute can be combined with other materials like plastics to create reinforced composites for various purposes.

Why Jute fiber is called golden fiber?

Jute fiber is called golden fiber for its color and high cash value. 

1. Color: The natural color of jute is golden or tan, resembling the hue of gold.
2. Versatility: Jute is versatile and used in various industries, including textiles, packaging, and agriculture, making it valuable like gold.
3. Economic Importance: Jute contributes significantly to the economy of many countries, particularly in South Asia, similar to the economic value of gold.
4. Environmentally Friendly: Jute is biodegradable and eco-friendly, contributing to its preciousness in sustainable industries.

The jute is a golden color, versatile like gold, economically and environmentally valuable as gold. 

Origin/Source:

1. Corchorus Olitorius (Dark jute or Tossa)
2. Corchorus capsularis (White jute)

Production Countries:

Bangladesh, India, Africa, Brazil, Japan, Myanmar, Nepal.

Production of Jute Fiber: 

Flowchart of jute fiber production are follows:

1. Cultivation Process
2. Land preparation
3. Sowing
4. Intercultural
5. Harvesting
6. Retting
7. Stripping
8. Washing
9. Drying
10. Bailing & Packing

1. Land preparation: the land is ploughed and cross ploughed. That means 1^st ploughing is in the direction of North-South and 2^nd ploughing is in the direction of East-West. This ploughing is repeated 6 to 8 times.

2. Sowing:  Sowing is done in two ways.

i) Line sowing: Sowing is done in lines. This is the latest method. 

3. Intercultural: 

i) Raking: Raking helps with rooting the weeds.
ii) Thinning: thinning is done to remove excess jute plants for better jute growing. 
iii) Weeding: Raking is followed by hand weeding. 

4. Harvesting: Jute is harvested any time between 120 to 150 days when the flowers have been shed. Early harvesting gives good healthy fibers.

5. Retting: Retting is a process in which fibers get less tight due to the rot of hard cell walls by the action of bacteria. The bundles are steeped in water at least 60 to 90 cm deep.

6. Stripping: Stripping is a process of removing the fibers from the stalk. It is done by any one of the following methods:

i) Single plants are laid hold of and their fibers are taken off. 
ii) Taking off a handful of stalks, breaking at one end, and stripping off the fibers by dashing it in a to and fro motion in water. 

7. Washing: Extracted fibers are washed in clean water. The dark color of the fibers can be removed by dipping them in tamarind water for 15 to 20 minutes and then washing them in clean water.

8. Drying: After washing, the fibers are hung on bamboo railings for drying which takes 2- 3 days. 

9. Bailing and Packing: The bailing of jute fiber is accomplished according to the grading system. Then the packing is done and transported to mills or jute market. 50 / 128 pdf

Defects of Jute Fiber: 

1. Rooty fiber: Due to underletting, barks and gums of the lower part of the jute fibers have not been completely removed. This defect is called rooty fiber.
2. Croppy fiber: Due to improper immersion in water, barks and gums of the upper part of the jute fibers have not been completely removed. This defect is called croppy fiber.
3. Knotty fiber: Due to insect bites, fibers have knots in places. This defect is called knotty fiber.
4. Specky / spotted fiber: Due to improper retting and insufficient washing, foreign materials stuck with the fiber and created a spot. This defect is called specky or spotted fiber.
5. Sticky fiber: If fiber is collected from an immature plant, the stick is clinging to the fiber. This defect is called sticky fiber. 
6. Mossy fiber: If jute plants grow in standing water, mosses grow and adhere to the jute plant. This defect is called mossy fiber. 
7. Hunka fiber: Due to insufficient removal of hard bark, a black spot is created in the outer layer of the jute plant. This defect is called hunk fiber. 
8. Weak fiber: due to over-retting, fiber loses its strength. This defect is called weak fiber.
9. Dead/ Dazed fiber: Due to over-retting, fiber loses its strength and color.  This defect is called dead or dazed fiber.
10. Heart damage: Due to improper drying, the shape of the bale form is changed. This defect is called heart damage.

Grading of Jute Fiber: 

(Based on the quality of raw jute)

Bd Grading System

Kutcha Grading

• Top 
• Middle
• Bottom
• B- Bottom
• C- Bottom
• X- Bottom
• Habijabi

Pucca Grading:

• White jute
• BW- special
• BW- A
• BW- B
• BW- C
• BW- D
• BW- E

Tossa Jute:

• BT- special
• BT- A
• BT- B
• BT- C
• BT- D
• BT- E

[BW = Bangla white, BT= Bangla Tossa]

Kutcah Grading: Grading is done before the barky ends are cut off.

Pucca grading: Grading is done after the barky ends are off.

Characteristics of different grades of pucca grading: 

BW special and BT special: Finest texture, very strong, long-lasting, free from any defect. 

BWB & BTC: Average strength, average luster.

BWD & BTD: Average strength

BWE & BTE: Any strength. 

Macro-Structure / Physical Structure: 

Longitudinal view

Lumen

Lignin

Cross-sectional view

1. A group of about 5 -15 ultimate cells cemented together laterally and thousands are longitudinally. 
2. The ultimate cells are spindle-shaped.
3. The cross-section of the ultimate cells is polygonal with rounded corners.
4. Each ultimate cell has a thick cell wall and lumen.

Microstructure: 

1. Lumen 
2. Micro fibrils
3. Secondary wall ( 7 – 9º)

Primary wall

1. The cell wall of each ultimate cell is composed of an outer thin primary wall and an inner thick secondary wall.
2. Both the walls of ultimate cells are compared to ultra-fine microfibrils.
3. In the primary wall, the fibrils are lying in a criss-cross manner. In the secondary wall, the fibrils are arranged in a right-handed spiral with angle of orientation of 7 – 9º.

Chemical Structure of Cellulose/ Cellulosic Structure: 

Cellulosic Unit

Methods of Upgrading Jute Fiber:

1. By the use of the improved type of chemical emulsion.
2. By the use of an improved type of emulsion mixing apparatus.
3. By using staple mixing.
4. By improved type of softening spreading m/c
5. By enzymatic methods.

A. Effect of Hemicellulose on Jute Fiber:

Hemicellulose is one of some heteropolymers present along with cellulose in all plants. The degree of polymerization of hemicellulose is about 50 – 200. 

Microfibrils are cross-linked together by hemicellulose homopolymers. Lignin assists and strengthens the attachment of hemicelluloses to microfibrils. 

B. Effect of lignin on Jute Fiber: 

Lignin is an aromatic polymer. It is the cementing element that attracts ultimate fibers, together and makes composite long fiber. It increases the strength, hardness, stiffness, and good resistance to bacterial degradation of fiber. It reduces the flexibility and extensibility of fiber. It is responsible for wider color range, and yellowing of jute on exposure to sunlight. 

Properties of Jute

Physical properties: 

1. Length of ultimate fiber: 1.5 – 4 mm
2. Diameter of ultimate fiber: 0.015 – 0.020
3. Fiber length: 5 – 12 feet
4. Specific gravity: 1.5
5. Moisture regain: 13. 75%
6. Color: White, off-white, yellow, brown, grey, golden.
7. Strength/ Tenacity : 3 – 4 gm/ den
8. Elongation: 1.7 %

Chemical Properties:

1. Effect of acids: Jute fibers are easily damaged by hot dilute acids and concentrated cold acids.
2.  Effect of alkalis: Jute fibers are damaged by strong alkalis. Fibers lose their weight when heated with caustic soda.
3. Effect of bleaches: Jute has resistance to bleach. H₂O₂, ch₃OOH, KMnO_4, etc are used as bleaching agents. 
4. Effect of organic solvents: Jute has resistance to organic solvents.
5. Effect of micro-organism: Jute is not affected by mildew. 
6. Effect of sunlight: Jute has poor resistance to sunlight. 

Chemical Composition: 

• Cellulose: 55 – 65 %
• Hemicellulose: 14 – 20 %
• Lignin: 12 – 13 %
• Moisture content: 13%
• Fat and Wax: 0.5%
• Pectin: 0.2%

Jute Fiber Identification Test:

1. Non-technical test: 

a. Feeling test: jute fiber is stiff and feels bad against human skin.

b. Burning test: Jute fiber burns easily but does not melt. The smell of jute burning is like that of paper burning because both are cellulosic materials.

2. Technical test:

Microscope test: polygonal shaped cross-section and many ultimate cells of longitudinal view easily identified jute fiber.

Solubility test: Jute is easily dissolved in chemicals in 58% H2SO4 in warm conditions. 

Application of Jute Fiber

1. Bags & sacks for packing almost all kinds of agricultural products like rice, potatoes, sugar, etc.
2. Wool packs and cotton bales.
3. Wrapping materials
4. Geotextiles
5. Blankets
6. Roofing and floor covering
7. Twines

Md Mahedi Hasan

Mahedi Hasan is a Textile Engineer, as well as a Top Rated content writer at Upwork, a Level 02 Seller at Fiverr, Level 02 Publisher at Ezoic. A passionate textile and fashion content writer, fashion SEO expert, and fashion web designer. Having a B.Sc. in Textile Engineering Degree from Textile Engineering College, Noakhali (TECN). The department is Apparel Engineering. Highly Experienced fashion writer for the last 3+ years. Have extensive 7 years of experience in the wholesale clothing business.