This presentation by Md. Yousuf Hossain discusses the production of viscose rayon. Viscose rayon is a regenerated cellulosic fiber produced from cellulose. The production process involves steeping pulp in sodium hydroxide, pressing, shredding, aging, xanthation, dissolving, ripening, filtering, spinning and drawing. Key steps include converting cellulose to cellulose xanthate and dissolving it to create a viscose solution that is spun into filaments and drawn. Viscose rayon is used in apparel and hygienic products due to its absorbency and thermal stability.

1. Welcome To My Presentation
Presentation On
Viscose Rayon Production
Presented By:
Md. Yousuf Hossain.
Id No. :120103063
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

2. Viscose Rayon:
Viscose Rayon is a re-generated cellulosic fiber. It is a manmade fiber and it is produced from the cellulose.
Viscose Rayon is also called as artificial silk.
Mainly viscose rayon is used as the alternatives of natural silk fiber.
Pulp is the raw material which is produced from the wood, seed hair, leaf, grasses and bamboo which contain cellulose.
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

3. Characteristics of Viscose Fiber :
Highly absorbent.
Soft and comfortable.
Easy to dye .
Drapes well .
Versatile.
It does not shrink when heated
It is biodegradable.
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

4. Properties Of Viscose Fiber:
i.Dry Tenacity (GPD) : 2.5 to 3
ii.Wet Tenacity (GPD) : 40 to 50% less
iii.Moisture Regain : 13%
iv.Lusture : Light to bright
v.Elasticity : Good
vi.Melting Point : ퟏퟓퟎퟎ풄
vii.Elongation Percentage : 20-25%
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

5. Raw Materials (Wood Pieces)
↓
Purification
↓
Pulp Preparation
↓
Steeping in NaOH
↓
Pressing
↓
Process Flow Chart In Viscose Rayon Production:
Although viscose rayon is a manmade fiber and it is produced by a spinning process.
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

6. Shredding
↓
Aging
↓
Xanthation
↓
Dissolving
↓
Blending
↓
Ripening
↓
Filtration
↓
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

7. Deairation
↓
Spinning
↓
Neutralization
↓
Purification
↓
Finishing
↓
Winding
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

9. 1. Steeping:
Cellulose pulp is immersed in 17-20% aqueous sodium hydroxide (NaOH) at a temperature in the range of 18 to 25°C.
Reaction:
(퐂ퟔ퐇ퟏퟎ퐎ퟓ)n + nNaOH ---> (퐂ퟔ퐇ퟗ퐎ퟒ−퐎퐍퐚)n + n퐇ퟐO
2. Pressing:
The swollen alkali cellulose mass is pressed to a wet weight equivalent of 2.5 to 3.0 times the original pulp weight to obtain an accurate ratio of alkali to cellulose.
3. Shredding:
This step provides increased surface area of the alkali cellulose, thereby increasing its ability to react in the steps that follow.
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

10. 4. Aging:
In this step the average molecular weight of the original pulp is reduced by a factor of two to three.
5. Xanthation:
In this step the aged alkali cellulose crumbs are placed in vats and are allowed to react with carbon-di-sulphide under controlled temperature (20 to 30°C) to form cellulose xanthate.
Reaction:
(퐂ퟔ퐇ퟗ퐎ퟒ−퐎퐍퐚)n + n퐂퐒ퟐ ----> (퐂ퟔ퐇ퟗ퐎ퟒO-SC-SNa)n
6. Dissolving:
The yellow crumb is dissolved in aqueous caustic solution.
7. Ripening:
The viscose is allowed to stand for a period of time to "ripen". Two important process occur during ripening:
Reaction:
(퐂ퟔ퐇ퟗ퐎ퟒO-SC-SNa)n + n퐇ퟐO ---> (퐂ퟔ퐇ퟏퟎ퐎ퟓ)n + nC퐒ퟐ + nNaOH

11. 8. Filtering:
The viscose is filtered to remove undissolved materials that might disrupt the spinning process or cause defects in the rayon filament.
9. Deairation:
Bubbles of air entrapped in the viscose must be removed prior to extrusion or they would cause voids, or weak spots, in the fine rayon filaments.
10. Spinning - (Wet Spinning):
Production of Viscose Rayon Filament.
11. Drawing:
The rayon filaments are stretched while the cellulose chains are still relatively mobile.
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

12. Spinning Bath Composition Of Viscose Fiber:
퐍퐚ퟐ퐒퐨ퟒ : 15-20%
퐇ퟐ퐒퐨ퟒ : 7-10%
퐙퐧퐒퐨ퟒ : 1-5%
Glucose : 1-2%
Spinning Bath Temperature : ퟒퟎ−ퟓퟓퟎ퐜
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

13. End-Uses
It is used in many apparel end-uses.
Often blended with other fibers, and in hygienic disposables where its high absorbency is of great advantage.
It is used very little in home furnishing fabrics but in the industrial field, because of its thermal stability.
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

14. Any Question?
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4.?
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com

15. Thanks To ALL
Md. Yousuf Hossain, Green University Of Bangladesh, yousuf_te@yahoo.com