2. M.L.V. TEXTILE & ENGG. COLLEGE, BHILWARA
(An Autonomous Engineering College of the Rajasthan Govt.)
for
The Partial Fulfillment of the Requirements for Degree of Bachelor of Technology
in
Textile Chemistry
SUBMITTED TO SUBMITTED BY
Dr. V.K.GUPTA
A Seminar on Chemical
Processing of Micro Denier Fabrics
BRIJMOHAN SHARMA
09EMBTC201

3. MICROFIBRES
. . . ?
Micro fibres are –
 Half the diameter of a fine Silk Fibre,
 One-Third the diameter of Cotton,
 One-Quarter the diameter of Fine Wool,
 And One Hundred times finer than Human Hair…

4. INTRODUCTION
 The growing demand to increase the fibre properties hitherto known,
and to create new sophistical application fields for textile materials
have been the causes of the rapid growth of microfibre technology
and the rising potential for the textile industry.
 Microfibres are half the diameter of a fine silk fibre, one-third the diameter of
cotton, one-quarter the diameter of fine wool, and one hundred times finer than
human hair.
 Fabrics made from microfibres are generally lightweight, resist
wrinkling, have a luxurious drape and body retain shape, and resist pilling.
They are also relatively strong and durable in relation to other fabrics of
similar weight, and they are more breathable and more comfortable to wear

5. Definition of MICROFIBRE
A microfibre is defined as a fibre of linear density
approximately
1 d tex or less and above 0.3 d tex ……
Relationship b/w fibre linear density and classification…
Fibre Count (d tex) Fibre Classification
> 7.0 Coarse
7.0 – 2.4 Medium fine
2.4 – 1.0 Fine
1.0 – 0.3 Microfibres
< 0.3 Super- Microfibres

6. History of Microfibres
 In 1970s
Very 1stly
Japanese fibre Manufacturing companies introduced
The first “micro-denier “ products.
 In 1980s - EUROPE
 In 1990s - American fibre manufacturers
At present , Polyester and Nylon are generally
used for manufacturing microfibres

7. PRODUCTION OF MICROFIBRES
Microfibres are generally considered to be fibres with a linear
density of less than 1.0 dtex.
Although the technology for microfibre production has been
available for many years now, strong
demand for these fibres did not begin until the 1980s. The currently
available microfibres are different
from ordinary fibres mainly in their dimensions, but have much
lower property differences than the
standard fibres.
Toray was the first company in the world to introduce microfibres,
followed by Teijin,
Hoechst, ICI, DuPont, and others. Recently Toray has introduced
an ultra-fine polyester microfibre
with a linear density of filament of about 0.05 dtex. This may be
called the finest synthetic fibre so far
produced commercially.

8. WHAT SHOULD BE THE QUALITY OF THE
CHIPS FOR MICROFIBRE ?
• Composition should be consistent
• Should not contain foreign matters
• Moleculer weight distribution curve should also be narrow
• Short term viscosity must be kept as much as possible
• polymer chips should be smooth and identical in shape/size
• Due to high value of microfibres, the use of “off – quality ’’ chips
should be avoided
 It is also important to maintain the quality of the product in all subsequent steps.
The drying process should be as consistent as possible, and chips must have an
even residence time. The moisture regained of the dried chips should be less than
0.005%, to minimize the hydrolytic degradation in molten stage.
 For drying quality chips, a continuous drying process is better than batch
drying.

9. METHOD OF MANUFACTURING MICROFIBRES
a) DISSOLVED TYPE
 Microfibres of this type are manufactured from bi-component fibres with different
types of polymers.Comparatively thick bi-component filaments containing different types
of incompatible polymers are spun, and the fabric is made using them.
 When the fabric is treated chemically with solvent, one component is dissolved and
removed, and the other component remains as the microfibre. Polyester and nylon microfibres
can be made by this method.
 Commercial production has been reported to use 20/80 ratios of soluble/insoluble polymers
to produce a bi-component filament of up to 2 dtex fineness, and a final dissolved filament with
linear density of about 0.50 dtex.
The main considerations for selection of suitable polymer component are:
 High solubility;
 Stability at extrusion temperature;
 It should be recoverable for use, so that the cost of solvent and soluble polymer is affordable;
 It should be non-toxic, non-corrosive, and non-polluting.

10. Bi-component Fibres
 Bi-component fibres are co-extruded with two different polymers in the
cross-section. This allows the fibre to use the properties of both materials,
and vastly expands the array of possible fibre performance characteristics.
 Bi-component fibres are available in staple, filament, and microfibre
forms.
 Typical bi-component fibre types are presented below in fig…….

11. a) sheath/core
b) Eccentric
sheath/core c) side-by-side
d) Pie wedge
e) hollow
pie wedge
f) islands/sea
g) three islands

12.  A modified cross-section can provide added functionality, such as
unique lustre or moisture transport.
 These cross-sections are available in staple, filament and microfibre
forms, and in most cases, are also available as bi-component fibres.
 Typical microfibres with special cross-section shape, commonly used,
are presented in Figure - - -
a) hollow b) trilobal c) ribbon d) 4DG™
Figure -- Typical microfibres with special
cross-section shape
Specialty Cross-Sections

13. Figure - Scanning electron microscope images of microfiber fibre
a) top view of microfibers b) cross-section of microfibre

14. b) SPLIT TYPE
The microfibres of this type are obtained by physically or chemically
treating the bi-component filaments containing two types of polymers and
splitting them into different types of filaments.
It is easier to split the segment in filament from itself than in the
fabrics. Suitable polymer combinations for splittable bi-component
filament spinning are polyamides/polyester and polyester/polyolefines.
The main considerations for selecting the polymer combinations are as follows:
 The polymers must be incompatible;
 The polymer should have reasonably similar melt viscosities at common extruder
temperature;
 The polymers should have weak adhesivity.
An example of a splittable fibre is presented in Figure-
Figure - Cross-sectional
photomicrograph of a 16-segment
splittable fibre

15. SOME OTHER METHODS
1. DIRECT SPUN METHOD
2. SUPER-DRAWING TECHNIQUE
3. SHEATH-CORE SPINNING METHOD
4. FLASH-SPINNING METHOD
5. SOLUTION FLASH-SPINNING
6. EMULSION-SPINNING METHOD
7. JET-SPINNING METHOD
8. CENTRIFUGAL-SPINNING METHOD
9. TURBULENT FORMING METHOD
10.CONJUGATE-SPINNING METHOD

17.  Carding
 It has so far proved impossible to card microfibres at production
rates which are comparable with conventional type of fibres,and
So the cost per unit weight of production is much greater. In carding it
is necessary to have a greater density of carding wire points.
 Winding and warping
 All guide surfaces must be very smooth and in the best mechanical
condition, as microfilaments are likely to break more easily than regular
filament.

18.  Sizing
 Warp sizing of microfibres should ideally be done on
single-end sizing machines to minimise filament breakage at splitting rods.
 The size pick up on microfibre yarn is higher and it is also more desirable.
Weaving
 Generally the tensions should be kept as low as possible.
 Weft yarn for air jet or water jet looms will need some
finish to perform at maximum efficiency.

20.  Due to their fineness, the total surface area
of microfibre yarn or fabric is far greater than
ordinary fibres. Threfore
1. Due to its special structure ,micro fibers has much larger quantity
of size ,oil agents and wax on warp yarns.
2. Since microfibres have very small interstitces, with consequent
difficulties of size accessibility and duffusibility,
desizing becomes quite difficult and costly.
3. Microfibres have greater absorption area resulting in a dyeing rate
four times higher than that of normal, which can cause unlevelness in dyeing.
4. They also require more dyestuff than standard fibres to obtain the same
depth of shade.
5. Larger external surface means an increase in number of threads exposed
to light which, on destruction of dye, is expressed as lower light fastness rating.
6. Washing fastness and color fastness to rubbing is also poor.

21.  The problems in wet processing of
microfibers can be overcome by --
1. Better knowledge about the size applied and optimum
parameters during desizing operation
2. Pre-setting
3. Alkali weight reduction
4. Careful selection of the dyes
Properties should be –
i. Compatible
ii. Having same exhaustion rates
iii. Having high washing fastness properties
iv. Good migration and Levelling properties

22. 5.Optimizing the dyebath conditions and dyeing cycle.
Optimized dyeing cycles can be worked out by controlling the temperature
to account for the high rate of dyeing and to eliminate the risk of uneven
dyeing. Chemicals and dyes to be added at, at least 10-20 °C lower
temperature than normal polyester fiber dyeing. The additions of dyes
must be progressive or devided at least into 4 parts. The heating rate
must be slow from 40 deg C to 100 deg C. 10-20 min more holding time
required at 130 deg C as compared to normal Polyester.

23. 6. Proper selection of Dyeing machinery.
7. Proper selection of dye bath additives such as
Levelling agents :- A strong levelling agent which
shall start working at lower temperatures
Dispersing agents :- Higher quantities of dispersing agents
are needed because amount of dyes required are more to produce
the desired depth
8. Proper after treatment of dyed goods
 Soaping
 Reduction clearing
 Washing

24.  General properties of microfibres
1) Light weight and Flexiable
2) Good stability and Shape retention
3) Anti-wrinkle property
4) Have a wicking ability that permits perspiration
5) Comfortable to wear
6) Doesn’t water stain – Super water repellency is available
7) Woven or knitted into a very high quality fabric construction
8) Strong and durable, water repellent and wind resistant – so tightly
woven ,that the fabric can’t be penetrated by wind, rain or cold
9) Washable, dries quickly and also washable in at the water temp.
up to 200°c and their characteristics will remain same.
10) Electrostatic effect – hair, lint and other dust particles are attracted
and grabbed by the microfibres without lifting dust.

25.  General properties of microfibres
11) The density of the material allowable it to grip six to eight
times its weight in water hence high absorbing power capacity.
12) The attraction capability of the microfibers is so sound, even
absorbs bacteria and germs - hence can be use as germ or
bacteria free purpose.
13) Comfortable - very soft, texture like silk, lightweight
14) Due to its fineness and superior fiber surface area making deep,
rich and bright colors achievable
15) Less "sweaty" in warm weather than usual synthetics
16) Quickly cleanable - clean just with water
17) Change without help - to establish lovely drape
18) Microfibres are environmentally friendly.

26.  Applications of microfibres -
 Fashion clothing textiles
 High-performance filter fabrics
The characteristics of microfibre liquid filters are as follows:
 high water passage speed,
 high extraction performance (retention of particles up to
micrometers dimensions), and
 ease of cleaning micro-particles from the filter.
 Protection against the weather
 Medical applications

27.  Microfibres for cleaning
 Microfibre products are suitable for cleaning anything. Unlike ordinary cleaning
fabrics that move or push dirt and dust from one place to another, microfibres
actually ‘scrape’ the dirt or stain from the surface, and then store the dirt
particles in the fabric until it is washed.
 Microfibre cleaning clothes trap dirt and dust inside the cloth, and do not spread
dust or dirt around.
 The user can clean the cloths with water alone; no chemicals are needed.

28.  Some examples of general applications of
microfibres
 automotive application to improve air oil filtration, allowing
improved engine performance and extended life
 perfect for asthma and allergy sufferers, removing dust mites
without chemicals.
 used extensively for hair transplantation, which works to
conceal thinning hair
 Microfibres are also used in sports applications such as sports
wear, sports materials, etc
 Microfibres are extensively used as a luxurious apparel wear
 Microfibres as swing threads
 Microfibres for production of synthetic leather
 Computer mouse pads, along which the mouse can slide easily,
keeping the mouse ball clean at the same time
 Polishing cloths for wafers and hard disks, acoustic insulation,
high performance sound absorption panels and concert hall seat
covers, among other products.