This document summarizes advances in denim processing and finishing techniques. It discusses the manufacturing process of denim including yarn parameters and dyeing methods like rope and slasher dyeing. New developments in dyeing and finishing machinery are outlined. Common finishing techniques like stone washing, enzyme washing and bleach washing are described. The document also introduces some newer denim finishes like sand blasting, buffing and spraying effects. Finally, some uncommon varieties of denim like printed, crushed and petroleum washed denim are mentioned.

1. ADVANCES IN DENIM PROCESSING
By
Dhanraj Desai
Under the guidance of
Dr. M D Teli sir

2. INTRODUCTION
• The term "Denim" has originated from the city of Nimmes in
France where “Serge de Nimmes" was manufactured.
• A fabric made from 100% cotton and having twill construction
(diagonal) is called denim.
• The classical denim is a heavy fabric made from 100% cotton
and woven from coarse indigo dyed warp and grey undyed weft
yarn.
• The traditional denim is hard-wearing, high density fabrics with
a high mass per unit area and a 3/1 or 2/1- twill weave
construction.
• Denim is made from a vat dye, the Indigo dye, which is applied
to cotton fabric in loosely held form in layers.

3. MANUFACTURING PROCESS OF DENIM

4. YARN Parameters FOR DENIM production
Parameters Ring Yarn OE Yarn
Tenacity cn/tex 15 – 16 11.5 – 12
Elongation % 7.5 8
Uniformity CV% 13.5 14.6
Thin places per 1000
m
8 5
Thick places per 1000
m
70 20
Neps per 1000 m 60 60

5. DENIM DYEING
• It is of Two types
a) Sheet form dyeing type.
b) Rope form dyeing type.
• Dye Used
a) Indigo
b) Sulphur

6. ROPE DYEING UNIT
ENTERING FEEDING

7. Cont.….
DYEING AIRING/OXIDATION

8. CONT….
DRYING DELIVERY

9. STYLES IN DYEING
• SDINDIGO
• SDSBIT
• DIBST
• LBIT
• LGBIT
• SBBIT

10. Advancements in rope dyeing machine
• Hunter lab installed in the coiler section which measures L , a , b
values and is connected to computerized system gives the dyer the
power to take correction if the shade is going wrong.
• Front-to-front bath circulating system.
• Big delivery pumps for higher recycle/hour of the dyeing bath.
• Caustic soda and sodium hydrosulphite automatic dosing systems with
special dissolving device.
• Oxidisers groups with big diameters rollers, short laps and extreme
ergonomics.
• Ground fitted colour kitchen tanks.
• Drying rollers groups with side housing and suction hoods for a safe
working environment.

11. SLASHER DYEING

12. Advancements in slasher dyeing machine
• Half circular bottom and double flow, on all width (pat.) dyeing vats
for an even and total bath rechange, without turbulences and with
reduction in hydrosulphite consumption.
• Special construction vats for each specific use and/or treatment, to
get the maximum operative quality and flexibility.
• Feeding of the reinforce bath to each single vat by compensate
circulation system, guarantee of dyestuff concentration evenness.
• Stainless steel/rubber squeezing pads with big diameter equipressure
rollers, for an even squeezing at each working pressure.
• Mixing/circulation bath group with ponderal dosing system and
hydrosulphite dissolving and set of n° 5 baskets for total filtering.

13. CONT……
• Mixing/circulation bath group with ponderal dosing system and
hydrosulphite dissolving and set of n° 5 baskets for total filtering.
• RapidSky” (pat.) oxidation enhancing devices with differentiated
effect, they reduce even the yarn stress and the wastages at lot
change.
• Enhanced washing units “EcoWash” (Pat.) with three sections vats
with half circular bottom, with guided circulation and with
internal counter flow, for an effective action and sensible water
saving.
• Benninger advancements.
• Innovative Pad Sizing Ox process developed by clariant.

14. PAD/SIZING-OX PROCESS By Clariant

15. ADVANTAGES OF PAD/SIZING-OX PROCESS
• DYEING
1. Quick shade stabilization & efficient colour shift Easy correction and adjustment
of shades.
2. High productivity & reproducibility.
3. Suitable for wash-down effects.
4. Good level of fastness.
• SIZING
1. Good adhesive power.
2. Good water solubility.
3. Stable to alkaline conditions.
4. Insensitive to high humidity.
5. Excellent size film.
6. High performance also on high speed looms.

16. SLASHER DYEING v/s PAD/SIZING OX PROCESS

17. DENIM Washing or FINISHING OF DENIM
• In denims, washing is done to produce effects like color fading with
or without patchiness, crinkles, seam puckering, hairiness, de-pilling,
softened-hand feel, stabilized dimensions etc.
• Normally the process of denim washing involves stages like product
evaluation and preparation desizing, braiding, bleaching, anti-
chlorine / post scouring, over dyeing (optional), softening, hydro-
extracting and tumble drying. Various process effects for special
products can be obtained by using combinations of these procedures.
Different processing parameters can be set for each stage to enhance
and improve the effects.
• Since denim constitutes the largest portion of the garments that are
washed, the term 'wash' has come to mean the finishing of denim
garments.

18. STONE Washing
• This method is most common and is used to give denim an 'old-look'.
• Pumice stone is one of the most important components used to
abrade the surface of the fabric to obtain a surface pattern effect with
color contrast and soft - handle.
Pumice Stones
• They are a light weight, highly porous rocky
substance which will float on water.
• It is a common product as a result of explosive volcanic eruptions.
• The world’s major pumice stone supplying countries are the U.S.A,
Turkey, Italy, Germany, Iceland, New Zealand, Japan, Indonesia and
Philippines etc.

19. Cont.….
• In this process, the fibres on the surface of
the fabric are broken and removed and the
inner white fibres of the warp yarn are
gradually exposed.
• Natural patterns can be formed as the degree
of abrasions varies in various parts of the garment.
• The degree of colour fading depends on the
washing time, stone ratio, sizes of stones, liquor
ratio and garment load.

20. ENZYME Washing
• This is a bio-catalytic method wherein an
ultra-soft handle effect can be produced on
denim. The hydrolytic effect of enzymes
causes the loss of surface fibre, which
improves surface smoothness and softness
of the fabric.

21. Bleach washing
• This process is usually done without stones by using
an oxidative bleaching agent like hypochlorite.
• Sodium hypochlorite is normally used as it is cheap,
convenient and quick.
• Other agents used are sodium percarbonate and
sodium perborate.
• A bio-bleaching technique known as "DeniBleach
Technology" has recently been introduced by Novo
Nordisk.

22. Cont.…
•

23. Acid or ICE or Snow washing
• This is achieved by dry tumbling with pumice stones soaked with
bleaching agents to produce a 'snow' pattern effect on denim.
• Stones are used to deposit a chemical on
garments to strip off the colour.
• This chemical deposit removes colour only
from the outer surface of the garments and
produces a frosted appearance.
• Indigo and selected sulphur dyes are the most
popular candidates for this procedure.

24. NEW DENIM FINISHES

25. NEW DENIM FINISHES
Sand blasting
• Sand blasting technique is based blasting an abrasive material
in granular , powdered form through a nozzle at a very high
speed and pressure on to specific areas of the garment surface
to be treated to give the desired distressed /abraded /used look.
• This process is used to obtain localized abrasion effect. The
abrasion force rubs off the indigo-dyed fibres.
• Blasting jeans with silica sand produces the desired vintage
look.
• The abrasive material can be quartz, emery, granite, silicon-
carbide, boron-carbide, aluminum-oxide and chilled iron.
However in practice, oxides of aluminum and copper with
certain auxiliaries are widely used.

26. CONT….

27. New denim finishes
• Buffies/Moustache
These are the lighter-colored contours running across the trousers
that look like real seat creases. The pair of jeans is treated by
hand with fine sandpaper according to the designer’s draft.
The sanding of these wear creases is also referred to as scraping.
• Spraying
Spraying the jeans with a solution of potassium permanganate
produces even traces of wear.

28. cont.….
• Plies
To generate wrinkles, the material is twisted slightly and fixated
with synthetic yarn. After washing, the strands of yarn are cut
and removed. There is significantly more dye in the wrinkles than
in the surrounding material.
• Brush effect
To enhance the bleaching results, the denims are brushed with
potassium permanganate several times.

29. Cont.….
• Baking
To add three-dimensional creases to the optical effect, the
jeans are tied together in the desired areas and sprayed with
a special synthetic resin. Afterwards, bake the trousers
in the oven.

30. SOME UNCOMMON DENIM
Printed Denim
• Denim printed with pattern such as batik or floral pattern often in
contrasting colours mainly meant for adolescents.
Crushed Denim
• Textured effect achieved through a special fabric construction
coupled with wet processing.
• Fabric is woven with an over twist weft yarn.
• On washing the yarn shrinks, acquiring a goffre look.
• The effect can also be improved by bleach and stone wash.

31. CONT….
Marble Denim
• It is an another name for acid wash.
• Some crushed denims, if strongly bleached, are also called
marble.
Petroleum Wash
• Developed in 1992 by US brand Williwear.
• A left hand denim is enzyme washed until it has lost most of the
colour.
• It is then overdyed and put through a silicone wash, which gives it an
oily coating and, in turn a super-soft, butter like hand.

32. THANK YOU