Nylon is a synthetic polymer made from polyamides through a process called polymerization. There are two main types: nylon 6, made from caprolactam, and nylon 6,6, made from adipic acid and hexamethylene diamine. The manufacturing process involves polymerization to form nylon salt, extrusion through spinnerets, then spinning and quenching to form strong fibers. Nylon fibers have properties like strength, elasticity and resilience making them suitable for applications in textiles, carpets, clothing and more.

1. DONGHUA UNIVERSITY
Betemariam Limenewu
My Chinese Name is Ge liming
Ethiopia
Textile Engineering (Masters)
ID No: 320023
Nylon fiber Processing

2. Outline of presentation
• Introduction
• Difference between nylon 6 & 6,6
• Manufacturing process of Nylon 6 & 6, 6 fiber
• Properties of Nylon fiber
• Application of Nylon fiber

3. Introduction
Nylon is the most useful synthetic material with applications
varying from daily life activities to industries. The term nylon
points towards a polymer family known as linear polyamides.
There are two approaches to making nylon for fibre
applications. In the first approach, the molecules that consist of
an acidic group (COOH) on every end react with molecules
that contain amino (NH2) groups at each end.

4. Conti…
Nylon is made by a process called polymerization (condensation
polymerization reaction), in which individual short molecules form
long-chain macromolecules with high relative molecular mass. In the
process of making Nylon fibers giant chain like polymers form amide
groups which then go on to form strong hydrogen bonds. These
hydrogen bonds hold the adjacent chains together and the resultant fiber
is an exceptionally strong Nylon fiber.

5. Difference between Nylon 6 & 6, 6
i. Nylon 6
Nylon 6 is made by heating Caprolactam to about 250 oC with about 5-
10% water thrown in. Nylon 6 is only made from one kind of monomer, a
monomer called caprolactam. Nylon 6,6 is made from two monomers,
adipoyl chloride and hexamethylene diamine.

6. ii. Nylon 6, 6
Nylon 6, 6 is a linear condensation polymer made from hexamethylene
diamine and adipic acid. Specific amounts of the two chemicals are
combined in solution to form nylon salt. This salt is purified, polymerized,
extruded in ribbon form, and chipped into small flakes or pellets. These
flakes or pellets are melted and extruded through a spinneret into cool air
and the nylon filaments are formed.

7. Conti..
• Nylon 6,6, polyamide Condensation product of aliphatic
diamine with aliphatic diacid.
Polymer 3D model of Nylon6,6

8. Conti.
• Nylon 6 structure is derived from one monomer, which
is a molecule that can be bonded to other identical
molecules to form polymers. The nylon 6 monomer has
six carbon atoms, hence the name nylon 6.
• Nylon 6/6 structure is made from two monomers. Each
of these monomers has six carbon atoms, which is
reflected in the name nylon 6/6.

9. Nylon fiber Manufacturing Process
Adipic acid, hexamethylene diamine, and water are added
to a reaction vessel to form Hexamethylene Diammonium
Adipate, common known as “Nylon salt” solution. After
evaporation, water continues to be removed from the “salt
solution”. The nylon polymer is then extruded through
spinnerets or pelletized.
A slurry of TIO2 pigments and water, used to deluster fibers,
is added to the Nylon salt. Polymerization begins in the
reactor where polyhexamethylene adipamide, (Nylon 66), is
formed. The Nylon polymer is then extruded through
spinnerets or pelletized.

10. Conti..
Nylon fiber manufacturing process

11. Spinning process of Nylon fiber
The spinning of nylon 6 is done by using the “melt
spinning” process. In this process, the polymer gets melted under
exclusion of air at a temperature of 250 °C- 270 °C ( 30 °C-50 °C more
than the melting point ). For a very homogenous melting process, the
polymer is melted in an extruder. The hot and molten polymer is fed
to the spinnerets with the help of a feeding pump and extruder. This
molten polymer passes through very small holes of spinnerets. “Thus
the nylon 6 filament is formed”.
On the lower part of the spinneret, the filaments are entered the
quench duct. This is a part of 2-4 metres where the still hot filaments
are quenched with air. It is very important to keep the airflow very
gentle and stable to avoid the filaments sticking together.

12. Manufacturing nylon fibers and nylon yarns, as
explained in the following:
• Polycondensation
This is a chemical process to produce the nylon polymer
using caprolactum and acetic acid.
• Chipping
The nylon rope produced from the polymerization process is
cut into chips.

13. Conti..
• Melting
In this stage nylon chips are melted to reach the viscosity suitable
for pumping to the spinning process.
• Spinning
In this process, molten nylon is pumped to spinnerettes, and the
polymer streams coming out are cooled by blown air that let the
polymer solidifies and form continuous nylon filament.

14. Properties of Nylon fiber
• Shape: Shape is controlled by the manufacturer, filaments are uniform and
long.
• Luster: Bright to Dull
• Elastic Recovery: 100%
• Elongation: Good
• Resiliency: Good
• Density: 1.1 g / ccm
• Moisture absorption: 8%

15. Conti…
• Dimensional stability: Excellent
• Acids: resistance is poor
• Alkalies: Good resistance
• Sun light: Generally affects
• Insects: Normally damages
• To flame: Self extinguishing

16. Application of Nylon Fiber