Polypropylene fiber is the fourth most popular synthetic fiber. It is made from the polymer polypropylene through processes like gas phase or bulk phase polymerization using catalysts. The fibers are then manufactured through melt spinning and extrusion. Polypropylene fiber has good chemical and physical properties like acid and alkali resistance, low density, and elasticity. However, it has low melting temperature and is difficult to dye. Major applications of polypropylene fiber include nonwovens for products like medical fabrics and construction materials due to its performance and low cost.

1. POLYPROPYLENE FIBER
An Overview of Polypropylene fiber

2. CONTENTS
INTRODUCTION
PROPERTIES
MANUFACTURING
ADVANTAGES & DISADVANTAGES
APPLICATIONS
CONCLUSION

3. Polypropylene is the first
polymer to have achieved this
much industrial importance.
The fibres from Polypropylene
were introduced to the textile
arena in the 1970s and have
become an important member
of the rapidly growing family
of synthetic fibers. Today
Polypropylene enjoys fourth
spot behind the “big three”
fibre classes, i.e. polyester,
nylon and acrylic. However, as
opposed to other commodity
fibres, its use as apparel and
household textiles has been
rather limited; the bulk of the
fibre produced is used for
industrial applications.
INTRODUCTION

4. WHAT IS POLYPROPYLENE?
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.
Most polypropylene used are 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).

6. Polymerization of
polypropylene using a
catalyst in following phases:
• Gas phase: In this
process, gaseous
propylene associates
with solid catalyst in a
fluidized-bed reactor.
• Bulk-Phase: In this
process, liquid propylene
makes connection with a
solid catalyst inside a
loop reactor.
MANUFACTURING
OF
POLYPROPYLENE
• Gas phase
• Bulk-Phase

7. MANUFACTURING OF POLYPROPYLENE
Polypropylene chips can be converted to
fiber/filament by traditional melt spinning,
though the operating parameters need to be
adjusted depending on the final products.

8. MANUFACTURING OF POLYPROPYLENE
Polypropylene Chips
Extrusion
Winding

9. The polypropylene chips are
melted and then extruded
through the spin head. The
metering pump controls the
flow of molten liquid to the
spin head, where it is filtered
before extrusion to ensure
any un-melted are removed
so that they do not form pert
of the fibre, which would
cause weak points. The
quench air cools the fibres
as they emerge.
MANUFACTURING
OF
POLYPROPYLENE

10. PROPERTIES OF POLYPROPYLENE
▪ Polypropylene fibers are composed of crystalline and non-
crystalline regions.
▪ The degree of crystallinity of PP fiber is generally between
50-65%, depending on processing conditions.

11. CHEMICAL PROPERTIES OF POLYPROPYLENE
Acid does not affect on polypropylene. It has excellent protesting ability against acids.
The fiber show excellent resistance to alkalis with exception of some oxidizing agents.
It has enough ability to prevent the harmful action of bleaching agent under 65oC.
The insects and related pests cannot easily digest polypropylene

12. CHEMICAL PROPERTIES OF POLYPROPYLENE
Since polypropylene molecular chains have no polar functional groups (active sites
for chemical bonds, or dye sites) and relatively high crystallinity (50-65%), dye
molecules cannot be chemically attracted to the fibres. Adsorbed dye molecules
which interact with the fibre surface by weak vander Waal’s force are easily washed
away because of polypropylene’s hydrophobic properties.
Water has no effect on the strength of polypropylene fibres.

13. PHYSICAL PROPERTIES OF POLYPROPYLENE
Tenacity: 3.5 –
8.0 gm/den
Density: 0.91
gm/c.c
Elongation at
break: 10 – 45%
Elasticity: Very
good
Moisture Regain
(MR%): 0%
Resiliency: Good
Melting point:
1700C
Lusture: Bright
to light

14. OTHER PROPERTIES
It is resistant to sunlight. Strength, color fastness and degradation can be
effectively protected by means of stabilizers.
The abrasion resistance of polypropylene approaches that of nylon and is superior
to that of other fibres, and is good even when wet.
The melting point of polypropylene is about 165°C and while it does not have a
true softening point temperature, the maximum processing temperature of the fibre
is approximately 140°C. Prolonged exposure to elevated temperatures will cause
degradation of the fibre

15. ADVANTAGES OF POLYPROPYLENE
PP is a light
fibre, its
density (.91
gm/cm³) is the
lowest of all
synthetic
fibres.
It does not
absorb
moisture
therefore has
quick moisture
transport.
It has excellent
chemical
resistance. PP
fibres are very
resistant to
most acids and
alkalis.
The thermal
conductivity of
PP fibre is
lower than
that of other
fibres

16. DISADVANTAGES OF POLYPROPYLENE
Polypropylene
fiber has low
melting
temperature,
and so requires
extra care
during ironing.
Hard to be
dyed after
manufacturing,
except after
substantial
treatment and
modification,
Poor resilience
compared to
PET and Nylon,
Polypropylene
undergoes
creep due to its
lower Tg(15 to
20C)

17. APPLICATIONS
Polypropylene fibers have superior performance characteristics and
comparatively low-cost, therefore it finds extensive use in the
nonwovens industry. PP is a very important fiber in nonwoven
processing and dominates in many nonwoven markets.
Some of the PP products may include:
▪ PP woven socks
▪ Ropes and Twines
▪ PP construction / industry fabrics
▪ Substrate fabrics
▪ Medical/Surgical disposable fabric etc.

18. CONCLUSION

19. REFERENCES
1. History of polyolefin's By F.B. Seymour, Tai Cheng
2. Introduction to polypropylene: Properties, Catalysts
ProcessesBy Dennis B. Malpass, Elliot Band
3. The chemistry of Textile Fibers By Robert R Mather and
Roger H Wardman
4. Handbook of Fiber Chemistry, Second Edition, Revised and
Expanded edited by Menachem Lewin ,Eli M. Pearce
5. Manufacture Fiber Technology by VB Gupta and VK Kothari
6. Handbook of Textile Fibers: Man-Made Fibers by J Gordon
Cook