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Friday, April 3, 2015

Properties of Jute fibre

Jute

Jute is a natural cellulosic fibre. It is the golden fibre of Bangladesh. It’s important properties are discussed below:

Length
The reeds of Jute fibre vary from 3 to 14 feet long, depending on the grade, and they show taper from root to end. Thick reeds contain coarse fibre and thin reeds contain finer fibre. It constitutes with ultimate fibres of average length of 2.5mm.

Fineness
It is a coarse fibre. Its diameter varies from 6 to 20 microns.

Strength
FIbres are not so strong when compared with some other bast fibres but have good tensile strength. Fibres are naturally hard and brittle and break off with abrasion. Resistance to mechanical wear is low and not durable especially on exposure in moisture reduces its strength. Its extension at break is 2%.

Color
The best quality fibres are pale white or silvery grey, common qualities are brownish and greenish are inferior, roots are usually darker without any luster. Better quality fibres shows matt and pitted surface with very poor strength.

Luster
Better quality fibres have fairly high luster but inferior quality fibres shows matt and pitted surface with very poor strength.

Roots
Base portion of the Jute stems is more rigid and has a stronger supporting bark than the rest of the stem. This is due to longer exposure of this part to the action of the sunlight and water. During grade shorting, the root portion are removed by cutting and baled separately known as bale cutting.

Cleanliness
Cleanliness of fibre is an essential factor for high grade. Adhering portions of bark, specks sticks etc. are undesirable which affects grading according to their degree of presence.

Effect of chemicals
  • Water: Jute is a hygroscopic fibre i.e. it takes in or gives out moisture to its surrounding atmosphere. Under standard testing atmosphere, moisture content value is 12.8% and moisture regain value of this fibre is 14.6%.
  • Acid: This fibre is damaged by the action of strong acid hence wet processing on Jute fibre is not done in acid medium.
  • Alkali: It is safe in alkali medium; hence wet treatment is done on alkali medium.
Effect of biological agents and light
It is attacked and damaged by the action of micro-biological agents like bacteria, fungus, moths, insects etc. in worm damp condition. Yellowing of the fibre is observed due to the effect of sunlight.

Chemical composite
Chemical composite of Jute fibre are as follows:
Cellulose: 65.2%
Hemi cellulose: 22.2%
Lignin: 10.8%
Water: 1.5%
Fats and Wax: 0.3%

End use
Jute is used for making yarn, twine, rope, sacking, cloth, hessian cloth, carpet backing cloth, carpet, mat, wall cloth, shopping bag, and as packing materials.

Friday, November 7, 2014

An overview of Jute Emulsion

What is emulsion? | Emulsion making steps | Objects of emulsion application | Emulsion ingredients | Role of emulsion ingredient

Definition
Jute batching is of a simple nature, usually containing only the mineral oil, water and emulsifying agent. An emulsion is an intimate mixture of two immiscible liquids, one dispersed in droplets from inside the other. It has two phases – an external phase and an internal phase. The external phase is the water and internal phase is the mineral oil. Batching oil is normally golden, amber in color and water is colorless, but when the two are mixed as an emulsion, the resultant liquid is milky white.

Emulsion making steps –
1st step – To split up the oil into vast number of microscopically small drops.
2nd step – Disperse them throughout the water homogeneously.
3rd step – To prevent the droplets to re-unit or re-constitute themselves into one mass of oil.

Objects of emulsion application –
a.     To soften the jute by destroying.
b.     To make the jute fibre spinnable.
c.      To make the acceptable better yarn and remove hairiness.
d.     To reduce the amount of waste during processing.
e.     To improve cohesive force.
f.       To improve the drafting action.

Emulsion ingredients –
a.     Soft water.
b.     Emulsifier.
c.      Oil – In early days of the industry, whale oil was used extensively, because Dundee was a whaling port that time. But now mineral oil of light spindle variety is extensively used (known as JBO: Jute batching oil). Still small amount of whale oil is used in spinning fine yarns. Vegetable oil is now used in mfg product like food grade jute bags.
% of ingredients (std) –
1.     Water – 73.5%
2.     Oil – 25%
3.     Emulsifier – 1.5%
………………………...
     Total – 100%

Role of emulsion ingredients –
Water –
a.     Softens the fibre.
b.     Increases fibre extensibility.
c.      Prevent excessive fibre breakage at the cards.
d.     Makes the fibre to easily bend round the pins and rollers.
e.     Reduces wt. loss.
f.       Gives required dampness and flexibility.
Oil –
a.     Increase fibre cohesion.
b.     Helps in proper drafting.
c.      Reduces quick evaporation of water from the fibre body.
d.     Lubricates the fibre and helps their free movement during processing.
Emulsifier –
a.     Reduces surface tension.
b.     Stabilizes the emulsion.

Tuesday, August 12, 2014

Can turning and trumping (Packing) arrangement of jute

Can turning and trumping (Packing) arrangement of jute
In order that, the sliver may be packed neatly in the cans and to have highest packing density, there arrangements are necessary. The cans are placed on can turning plates at the front of the machine. These plates revolves 360o  in one direction and then reverse. The alternate rotation of the plates and hence the cans prevent the formation of any twist in the sliver, as formation of twist in the sliver resist drafting actions to the fibres in the subsequent operation to follow.

In addition to these can-turning plates, there are a series of can trumping (packing) arms, one for each delivery on the frame. These carry expanded metal feet or packing block at their bottom ends, the feet projecting into the cans. When the delivered sliver from the drawing frame reaches a certain height inside the sliver can, the packing block begins to press it. As the trumpers moves up and down it pack the sliver down into the can and allow greater quantities to be inserted.
Can packing arrangement
Can packing arrangement

Tuesday, January 14, 2014

Cross-sectional view of breaker carding

Cross-sectional view of breaker carding machine for half and full circular
Half circular down striker breaker carding machine:

 Half circular down striker breaker card machine.

                                                          Fig: Half circular down striker breaker card machine.
A = feed lattice

B = Feed materials

C = Fluted feed roller

D = Pin feed roller

E = Shell feed

F = Cylinder

G1G2 = Stripper

H1H2 = Worker
T1T2 = Tin cylinder
J = Doffer
K = Pressing roller
L = Condenser
M = Delivery roller

Sunday, January 12, 2014

Types and flow-chart of jute processing

Types of jute yarn | Flow chart for traditional jute processing
Different types of jute yarn:
The composite mills traditionally manufacture the following types of yarns-
1. Fine yarn of 120-224tex (3.5-6.5lb/spy) to be used for carpets and various non-traditional end products like decorative fabrics.
2. CBC yarn of 224-293tex (6.5-8.5lb/spy) for using as carpet backing cloth or very fine cloth.
3. Medium coarse yarn of 241-414tex (7-12lb/spy) for:
                  * Hessian warp 241-310tex (7-9lb/spy)
                  * Hessian weft 241-414tex (7-12lb/spy)
                  * Sacking warp 276-345tex (8-10lb/spy)
                  * Other type of end products like canvas.
4. Coarse yarn of 483tex and above (14lb/spy and above) for sacking weft and coarse end-products like matting.
5. Piled yarns or twines of different counts.
Flow chart for traditional jute processing: 
Process flow chart of traditional jute yarn processing,Types of jute yarn.

Monday, September 30, 2013

Batch and batching

Selection  and Batching | Factors responsible for batch selection | Objects of batch selection | Definition of batching and emulsion

Selection  and Batching:
The selection of jute fibres from the assorted jute to produce a particular type of jute yarn is termed as the “batch”. It is done by a group of people called selectors who performed the task through a “ hand-and-eye” assessment.
                     
 
Factors responsible for batch selection:
The selection of a particular fibre batch for a particular type of yarn depends on- 
  • The basic fibre characteristics like-strength, color, entanglement, defects affecting the spinnability e.t.c
  •  Price of raw jute.
  •  Grade of jute.
  • Quality specification of  yarn.
  •  Availability of jute.
  • End-use of jute yarn/ product.
Objects of batch selection:
  •  To produce desired quality and type of jute yarn/ product.
  •  To control the cost of processing and product.
  •  To fulfill the demand of the clients.
Batching:
                In order to produce an acceptable yarn the jute fibre is conditioned(i.e, kept for a definite period of time by pilling) for spinning by adding oil and water to it-is called batching.
Emulsion:
                 Jute batching are of a simple nature, usually containing only the mineral oil, water and emulsifying agent. An emulsion is an intimate mixture of two immiscible liquids, one dispersed in droplets from inside the other. It has two phases-an external phase and an internal phase.The external phase is the water and the internal phase is the mineral oil. Batching oil is normally golden, amber in color and water is colorless but, when the two are mixed as an emulsion, the resultant liquid is milky white.     
Reference:
1. Hand book on jute-T.C Ranjan.
2. Jute fibre to yarn- R.R. Atkinson.
3. A guide to jute technology- Md. Sadar Uddin