Ielts Practise 2

8/18/2019 Ielts Practise 2

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Man Made production & Spinning process

Classification of Textile fibre :( See at page 2)

Forms of Man Made fibre: MMF are produced in three types –

1. Filament

2. Staple

3.

Filament tow.

1.

Filament: Filament fibres are spun from spinnerets with 350 holes or less is

determined by the size of the yarn to be made. The number of holes in the spinneret

determines the no of filaments in the yarn filaments are of two types:

Mono filament

Multi filament

Monofilament: This filament is made only of a single filament.

Multifilament: These filaments are made of more than one filament.

2.

Staple fibre: Staple fibre is of limited and relatively short length .Staple fibres are

made from filaments which are spun from large spinnerets with as many as 3000

holes. The length of the staple fibre depends on its use. Staple fibre is a unit of matter

which is usually at least 100 times longer than its thick.

3. Filament Tow: The product of 100 or more spinnerets is collected into a large rope

of fibres called Tow. This rope or tow is crimped and then made into staple by

cutting or breaking.


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F i b r e

N a t u r a l F i b r e

M a n M a d e F i b r e

O f A n i m a l

O r i g i n

O f M i n e r a l

O r i g i n

L e a f F i b r e S e e d F i b r e &

F r u i t F i b r e

B a s t F i b r e

A s b e s t o s

S y n t h e t i c

N a t u r a l P o l y m e r /

R e g e n e r a

t e d F i b r e

C e l l u l o s e

( R a y o n )

C e l l u l o s e

E s t e r s

M i s c e l l a n e o u s

P r o t e i n

P o l y a m i d e s

P o l y v i n y l

d e r i v a t i v e s

P o l y e s t e r s

P o l y o l e f i n e s

P o l y u r e t h a n

M i s c

e l l a n e o u s

P o l y a c r y l o n i t r i l e P o

l y v i n y l

C h l o r i d e

P o l y v i n y l i d e n e

C h l o r i d e

P o l y v i n y l

A l c o h o l

P o

l y t e t r a f l u r o

e

t h y l e n e &

R e l a

t e d p o l y m e r s

P o l y v i n y l i d i n e

d i n i t r i l e ( P V D N )

P o l y s t y r e n

e

M i s c e l l a n e o u s

O f

V e g e t a b l e

O r i g i n

R i p e n i n g


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Differentiate between Natural fibre & MMF:

Natural Fibre Man Made fibre

1. The fibre which we get from nature is

natural fiber. 1.

The fibers made by regenerationsystem.

2. Number of molecular wt is not limited. 2. Limited.

3. Hygienic fabric made from N.F. 3. Non-hygienic.

4.

Comfortable to wear. 4.

Uncomfortable.

5.

It cannot be made as our expected form. 5.

It can be made.

6. The no of molecules controlled by nature. 6. The no of molecules controlled by

man.

7. Dependent on climatic condition. 7. Independent production from

climatic condition.

Properties required for Fibre forming polymer:

Molecular weight should be high.

Resistance to different chemical.

Orientation – Physical and chemical symmetry.

Straight chain structure.

Glass Transition Temperature (Tg) – Should be near to Room Temp.

Crystalline Melting Point (Tm) - 200o – 300o c is suitable.

Polymer should be soluble in some solvent from which it can be spun.

Hygroscopic nature – Should be hydrophobic.

Chemical and Physical Modification of MMF:

1. Adding substance to the polymer or to spgn solution:

I)

Delusturant agents. i.e. Titanium oxide a while pigment.

II) Optical brightening agents. i.e. Derivatives of stilbene, paraxoline,

dibenzophenon.

III) Light stabilizer. ie. Polyhydroxy benzophenone.

2. Changing size and Shape of spinneret holes:

I) For carpet fibres – heavy denier from 15 – 24 den.

II)

For dilobal fibres – Silk like.

III)

For trilobal fibre – straw like or high lustrous.

IV) For Multilobal fibres – bulk.

3. Varying conditions of extrusion and solidification.

I) Thick and thin – Slub yarns and multi color effect.

II) Hollow filaments.

4. After treatments – high tenacity fibers are produced by drawing either during or

after spgn.


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Modifying the spinning solution:

The following modification arte made by the addition of substance to the spgn solution:

1.

Delusturing agent: TiO2, it prevents the reflection of the surface of the fiber. Variation

in the amount of pigment will control the degree of luster to produce semi dull or

dull fibers.

2.

Solution dyeing: Addition of colored dyeing / pigments or certain dyes to the spgn

solution or to the resin polymer. It is also called spun dyeing or dope dyeing.

3. Whitening agent: To resists the yellowing and to make whiter fiber fluorescent

whitening compounds (dyes) added to the solution. This whiteness is permanent to

washing and dry cleaning.

4.

Light stabilized: To make lightly resistant.

Spinneret: A nozzle or plate provided with fire holes or slits through a fiber forming

solution or melt is extruded in fiber manufacturing is called spinneret. This is the most

important part of a MMF producing m/c. The number of holes, sizes and shapes vary with

the filament desired.

Spinneret was 1st invented by OZANAM at 1862 A.D.

Spinneret is made of Platinum, Iridium, Rhodium, Stainless steel, Tantalum.

Shape of spinneret:

Features of Spinneret:

1. Spinneret holes are slightly wider at the entry than the exit.

2.

The denier of filament extruded through a hole does not depend upon its size, but it has

some significance on the efficient extrusion depending on melt delivery speed.

3. Special spinnerets are required for the production of hollow fibers and bicomponent

fibers.

4. After long use the spinnerets get checked and it is essential to clean them.

5. The spinneret holes may be broken spotted.


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Problems:

Breaking (On account of high pressure and temp)

Clogging (The holes can be blocked for solid particles mix with polymer solution).

Remedies:

For breaking problem: the spinneret is to be changed.

For clogging: the spinneret should be cleaned after some days.

Spinneret cleaning process:

I) Salt bath method

II) Sample burning method

III) Vacuum cleaner method

IV)

Solvent cleaning method

V)

Fluidized bed system

Ielts Practise 2

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