Brief introduction, production process and properties of the P family fibers

1. SYED FIAZ HUSSAIN
Introduction, History, Production Process,
Properties and Uses.

2.  Polypropylene is a100% synthetic fiber which is
transformed from 85% propylene. The
monomer of polypropylene is propylene.
Polypropylene is a by-product of petroleum.

3.  Phillips Petroleum chemists J. Paul Hogan and
Robert L. Banks first polymerized propylene in
1951.
 Propylene was first
polymerized to a crystalline
isotactic polymer by Giulio
Natta as well as by the German
chemist Karl Rehn in March 1954.
 This pioneering discovery led to
large-scale commercial production of isotactic
polypropylene by the Italian firm Montecatini from
1957 onwards.

4.  Syndiotactic polypropylene was also first
synthesized by Natta and his coworkers.
 Polypropylene is the second most important
plastic with revenues expected to exceed
US$145 billion by 2019. The sales of this
material are forecast to grow at a rate of 5.8%
per year until 2021.

5.  Polypropylene (PP) is a thermoplastic.
It is a linear structure based on the monomer
CnH2n. It is manufactured from propylene gas
in presence of a catalyst such as titanium
chloride. Beside PP is a by-product of oil
refining processes.

6.  Most polypropylene used is highly crystalline
and geometrically regular (i.e. isotactic)
opposite to amorphous thermoplastics, such
as polystyrene, PVC, polyamide, etc., which
radicals are placed randomly (i.e. atactic).

7.  It is said that PP has an
intermediate level of
crystallinity between low
density polyethylene
(LDPE) and high density
polyethylene (HDPE); On
the other hand PP has higher working
temperatures and tensile strength than
polyethylene

9.  Poly (propene) is produced from propene.
Propene is produced in large quantities from
gas oil, naphtha, ethane and propane.
 Ziegler-Natta catalysts are used in the
polymerization process. These are produced by
interaction of titanium (IV) chloride and an
aluminium alkyl, such as triethyl aluminium.

10.  There are two methods to make the polymer
for the production of Polypropylene fiber:
› Gas Phase Process
› Liquid Phase Process

11.  Gas Phase Process:
› Unipol®:
PP A fluidized-bed process with one or two
reactors for the production of
PPnhomopolymers, random polymers and
impact polymers.

13.  Gas Phase Process:
› Novolen®:
A gas-phase stirred-bed process with two
reactors in series for the production of PP.

14.  Gas Phase Process:
› A mixture of propene and hydrogen is passed
over a bed containing the Ziegler-Natta
catalyst at temperatures of 320-360 K and a
pressure of 8-35 atm.
› The polymer is separated from the gaseous
propene and hydrogen using cyclones and
the unreacted gas is recycled.

15. › Both processes can be operated continuously
and use 'stereo specific' Ziegler-Natta catalysts
to effect the polymerization. The catalyst
remains in the product and needs to be
destroyed using water or alcohols, before the
polymer is converted into pellets.
› Gas phase processes has virtually eliminated
gaseous and aqueous effluents by the use of high
activity catalysts, resulting in low residues in the
final polymer.

16.  Liquid Phase Process:
› Borstar®:
PP A supercritical slurry process, which
combines a loop reactor with gas phase
reactor.

18.  Liquid Phase Process:
› Spheripol®:
A slurry process for the production of PP
homopolymer plus random copolymers.

19.  Liquid Phase Process:
› In liquid-phase processes catalyst and
polymer particles are suspended in an inert
solvent, typically a light or heavy
hydrocarbon.
› Super-critical slurry polymerization processes
use supercritical propane as diluent.

20.  Liquid Phase Process:
› Slurry processes run in loop reactors with the
solvent circulating, stirred tank reactors with a
high boiling solvent or a “liquid pool“ in which
polymerization takes place in a boiling light
solvent.
› A variety of catalysts can be used in these
processes.

21.  Liquid Phase Process:
› Processes in solution require, as their last
step, the stripping of the solvent. Supercritical
polymerization in the slurry loop provides
advantages (e.g. higher productivity,
improved product properties) over subcritical
polymerization.

22.  Liquid Phase Process:
› Advanced processes combine a loop reactor
with one or two gas-phase reactors, placed in
series, where the second stage of the
reaction takes place in the gas-phase
reactors. For bimodal polymers, lower
molecular weights are formed in the loop
reactor, while high molecular weights are
formed in the gas-phase reactor.

25. › Polypropylene chips can be converted to
fiber/filament by traditional melt spinning. As
an example, the staple fiber production is
shown in the above figure.
› One or more spinning gear pumps receives
the molten polymer and sends it through the
spinning pack to homogenize the product,
feed the spinning pack at a constant rate, and
prevent fluctuation due to screw extruder.

26. › Polymer formed is passing through the
filtering media to remove the impurities and
other residues from it.
› Melt polymer is extruded through the jets of
spinneret (a metal nozzle device having a
number of holes in it for extrusion of polymer)
and air is provided through oench duct and
filament is formed which passes through the
certain rollers, steaming bath for stretching or
drawing. Filament fiber or yarn is also given
crimps in the crimpers.

27. › Filament fibers can be cut into 20 to 120 mm
length depending on whether they are intended
for cotton or woolen system.
› Spinning: the spinning pack consists of three
parts-filters, distributor (which distributes the
molten polymer over to die surface) and the die.
› Quenching: newly extruded filaments are cooled
in a good “box" which will distribute 3 m3/min of
cool air without damaging the filaments.

28. › Finishing: to improve antistatic and reduce
abrasion.
› Hot Stretching: to enhance the physico-
mechanical properties.
› Crimping: to improve the bulk.
› Thermosetting: it is a treatment in hot air or
steam that removes the internal stresses and
relaxes fibers. The resultant fibers are heat-
set with increased denier.

30. Polypropylene fibers are composed of crystalline and non-crystalline
regions. The spherulites developed from a nucleus can range in size
from fractions of a micrometer to centimeters in diameter. The a-axis of
the crystal unit cell is aligned radially and the chain axis is
homogeneously distributed in planes perpendicular to this radial
direction.

31.  Each crystal is surrounded by non-crystalline
material. Fiber spinning and drawing may cause
the orientation of both crystalline and
amorphous regions. If the extension is less than
0.5%, the spherulite deformation is elastic and
no disruption of the structure occurs, otherwise
spherulites are highly oriented in the direction of
the force and finally are converted to micro
fibrils. These highly anisotropic microfibrillar
structures lead to anisotropic fiber properties.

32. Tensile strength (g/den) 3.5 to 5.5
Elongation (%) 40 to 100
Abrasion resistance Good
Moisture absorption (%) 0 to 0.05
Softening point (ºC) 140
Melting point (ºC) 165
Chemical resistance Generally excellent
Relative density 0.91 g/cm3
Thermal conductivity 6.0 (with air as 1.0)
Electric insulation Excellent
Resistance to mildew, moth Excellent

33.  Effect of Acids
Excellent resistance to most acids except chlorosulphonic and concentrated
sulfuric acid.
 Effect of Alkalis
Excellent resistance with the exception of some oxidizing agents.
 Effect of Bleaches and Solvents
Excellent resistance. However, chlorinated hydrocarbons cause swelling at
room temperature and dissolve polypropylene at 71 °C. and higher.
 Organic Solvent
Organic solvent does not cause harm during action.
 Protection ability against light
It looses energy in sunlight.
 Protection ability against mild dew
Good.
 Protection ability against insects
It does not get affected by insects.
 Dyes
Difficult to dye polypropylene because its moisture regain is 0% . But pigment
dye is possible .

34.  Polypropylene is a major polymer used
in nonwovens, with over 50% used for diapers or
sanitary products
 Other uses include filters for air, gas, and liquids.
Such applications could be seen in the house as
water filters or air-conditioning-type filters.
Pipe Connections Filters Non Wovens

35.  The high surface area and
naturally oleophilic
polypropylene nonwovens are
ideal absorbers of oil spills with
the familiar floating barriers near oil spills on
rivers
 Polypropylene is also used in
warm-weather clothing, which
transports sweat away from
the skin
Oil Absorber
Clothing

36.  Polypropylene has been used in hernia and
pelvic organ prolapse repair operations to
protect the body from new hernias in the same
location.
 PP Chairs, sheets, bags are very important

37.  In the formation of colored ropes, plastic
products, gloves, clothing and non wovens.

38. Applications area of PP