viscose rayon fiber production process
TRANSCRIPT
Welcome To My Presentation
Presentation On
Viscose Rayon Production
Presented By:
Md. Yousuf Hossain.
Id No. :120103063
Md. Yousuf Hossain, Green University Of Bangladesh, [email protected]
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, [email protected]
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, [email protected]
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 : 𝟏𝟓𝟎𝟎𝒄
vii. Elongation Percentage : 20-25%
Md. Yousuf Hossain, Green University Of Bangladesh, [email protected]
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, [email protected]
Shredding
↓
Aging
↓
Xanthation
↓
Dissolving
↓
Blending
↓
Ripening
↓
Filtration
↓
Md. Yousuf Hossain, Green University Of Bangladesh, [email protected]
Deairation
↓
Spinning
↓
Neutralization
↓
Purification
↓
Finishing
↓
Winding
Md. Yousuf Hossain, Green University Of Bangladesh, [email protected]
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:
(𝐂𝟔𝐇𝟏𝟎𝐎𝟓)n + nNaOH ---> (𝐂𝟔𝐇𝟗𝐎𝟒 − 𝐎𝐍𝐚)n + n𝐇𝟐O
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, [email protected]
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:
(𝐂𝟔𝐇𝟗𝐎𝟒 − 𝐎𝐍𝐚)n + n𝐂𝐒𝟐 ----> (𝐂𝟔𝐇𝟗𝐎𝟒O-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:
(𝐂𝟔𝐇𝟗𝐎𝟒O-SC-SNa)n + n𝐇𝟐O ---> (𝐂𝟔𝐇𝟏𝟎𝐎𝟓)n + nC𝐒𝟐 + nNaOH
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, [email protected]
Spinning Bath Composition Of Viscose Fiber:
𝐍𝐚𝟐𝐒𝐨𝟒 : 15-20%
𝐇𝟐𝐒𝐨𝟒 : 7-10%
𝐙𝐧𝐒𝐨𝟒 : 1-5%
Glucose : 1-2%
Spinning Bath Temperature : 𝟒𝟎 − 𝟓𝟓𝟎𝐜
Md. Yousuf Hossain, Green University Of Bangladesh, [email protected]
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, [email protected]