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Textile Effects
INTRODUCTION
TO
PRETREATMENT
Textile Effects
Cotton
Bast fibres
other CEL fibres
Polyester
Polyamid
Polyacryl
other SYN fibres
Wool
Silk
56.5 % cellulose fibers39.5 % synthetic fibers
Fibre production
Textile Effects
High and even hydrophilicity / rewettability Good desizing effect High degree of whiteness Removal of seed husks Removal of foreign substances from the fibers Lowest possible fiber damage High color yield Neutral pH Levelness of the effects
Aim of the pretreatment
Textile Effects
Fibres (natural or synthetic materials)
Structure / Makeup / End use (Woven goods, knit goods, yarn ….)
Machine (Continuous, Discontinuous, Semi-continuous)
Chemicals (Wetting-/Washing agents, Complexing agents ….)
Pretreatment processes (Desizing, Scouring, Bleaching ….)
Pretreatment is dependent on
Textile Effects
POLYAMIDEPOLYAMIDE
VISCOSEVISCOSEWOOLWOOL
SILKSILKLINENLINEN
COTTONCOTTON
POLYESTERPOLYESTERACRYLICACRYLIC
Fibres
Textile Effects
m i n e r a l f i b e r
s i l k
t h i c ka n i m a l h a i r s
w o o l a n df i n e a n i m a l s h a i r s
w o o l a n d h a i r s
a n i m a l f i b e r
f r u i t f i b e r l e a f f i b e r
h a r d m a n s o n i t eb a s t f i b e r p l a n t h a i r
v e g e t a b l e f i b e r
n a t u r a l f i b e r
Asbestosa.o.
SilkTussah
Goat-hairBeef-hairHorse-hair
Wool (sheep’s wool)- Alpaca wool- Lama woolCamel-woolRabbit-hair- Angora woolGoat-hair- Mohair- Kashmir hair- Tibet hair
Coco SisalManila
FlaxHempJuteSunnKenafRamie
CottonKapok
Fibres: Classification of natural fibers
Textile Effects
P o l y a d d i t i o n s -f i b e r
P o l y m e r i s a t i o n s -f i b e r
P o l y c o n d e n s a t i o n s -f i b e r
c h e m i c a l f i b e r w i t hs y n t h e t i c p o l y m e r
T i e r e i w e i s s -f a s e r n
a n i m a ld e r i v a t i o n
v e g e t a b l ep r o t e i n f i b e r
g u mf i b e r
p a p e rf i b e r
c e l l u l o s i cf i b e r
v e g e t a b l ed e r i v a t i o n
c h e m i c a l f i b e r w i t hn a t u r a l p o l y m e r
c h e m i c a l f i b e r
PolyesterPolyamidePolyester-Ether
GumPolyamidePolyacrylPolypropylenePolyethyleneElastodienModal acrylVinylPolystyrolPolychloride
PolyurethaneElasthan
Casein
ZeinArdein
Spinning-paperCellulon
ViscoseCuproAcetateTriacetateModal
Fibres: Classification of synthetics fibers
Textile Effects
Discontinuoussystems
Semi continuoussystems
Continuoussystems
Pad steam,L/J/U box,
Immersion system,
Pad batch,Pad roll
Jigger,Jet,
Winch and other
Machines
Textile Effects
Machines: Discontinuous system
Textile Effects
Machines: Semi-continuous system
Textile Effects
Machines: Continuous system
Textile Effects
Ca Mg Fe Cu Mn
Brazil - Paranah 2700 1100 250 6 30- San Paulo 940 760 70 <1 6
Peru 700 440 15 <1 <1
USA - Texas 810 365 75 <1<1- California 600 540 40 <1 <1
Russia, Turkey,India, Pakistan 1300 570 110 3
6
Egypt 640 450 11 <1 <1mg/kg (ppm)
Ca Mg Fe Cu Mn
Brazil - Paranah 2700 1100 250 6 30- San Paulo 940 760 70 <1 6
Peru 700 440 15 <1 <1
USA - Texas 810 365 75 <1<1- California 600 540 40 <1 <1
Russia, Turkey,India, Pakistan 1300 570 110 3
6
Egypt 640 450 11 <1 <1mg/kg (ppm)
Analyses of different cotton qualities
Textile Effects
Surfactants (Wetting- and washing
agent)
Complexing agent / Cracking agent
Processor / Stabilizer
Defoamer
Enzyme
Chemicals
Textile Effects
The classical steps of pretreatment: cotton
woven goods
Singeing Burning down of the protruding fibers
Desizing Removal of sizing agents
Scouring/ Improvement in hydrophilicityAlkaline Cracking Cracking of seed husks
Removal of foreign substances
Acid Cracking Complexing/dispersing/cracking of
alkaline earth metals and heavy metals
Bleaching Destruction of colored substances
Removal of seed husks
Mercerizing/ Modification of the inner surfaceCaustifying
Textile Effects
To obtain a smooth,clean fabric surface (Napless / pile less finishing)Parameter :
• fabric speed (up to 250 m/min)• flame intensity (gas-/air-mixture; 1200-1300°C)• burner distance / burner position
receipt of goods brushing singeing tension beater impregnation batching
Singeing: Parex-Mather
Singeing
Textile Effects
Starch is a polysacharide and consist of:
• 14 - 27% amylose (water soluble)• 73 -86% amylopectin (water insoluble)
starch- amylosecontent in the starch
potato 20% 23%maniok/tapioka 25% 18%sago 27% 26%wheat/maize 60% 25%rice 75% 19%
Natural sizes Natural sizes (water insoluble)(water insoluble) Synthetic sizes Synthetic sizes (water soluble)(water soluble)
Polyvinyl alcohol size (PVA)Polyacrylate size (PAC)Polyester size (PES)
Carboxymethyl cellulose (CMC)
Desizing: Sizes
Textile Effects
Desizing
Starch CMC PVOH Acrylate PES VAcopolymer
CO ++ ++ + +
CEL/PES ++ + + + +
CV-staple ++ ++ + +
CV-filament ++
PAN ++ ++ +
PA-filament + ++
PES-filament + ++ ++
CA/CT ++ ++
Textile Effects
DESIZING
Starches
Starches in combination withwater soluble sizes
Water soluble sizes Starches
Starches in combination withwater soluble sizes
ENZYMATIC
OXIDATIVE
SURFACTANT
Desizing: Starch size
Textile Effects
Advantages of enzymatic desizing
• No fibre damage
• No use of aggressive chemicals
• A lot of process possibilities
• High biological degradability
Disadvantages of enzymatic desizing
• Low additional cleaning and cracking effect
• Low effects on certain starches, e.g. tapioca starches
• Effects can be reduced by certain size additives and other
impurities
Enzymatic Desizing - Advantages / Disadvantages
Textile Effects
Surfactants are water-soluble,
surface active agents
Surfactants are used in textile applications as,
Detergent Wetting agent Emulsifier Softener Lubricant
What are surfactants ?
Textile Effects
air
waterhydrophilic
hydrophobic
material
oil, wax or soil
Detergency / Washing power
Textile Effects
Boiling out is the treatment of cellulose under strong alkaline conditions.
Raw cotton contains a great number of foreign substances such as hemicelluloses, proteins, lignins, pectins, fats, waxes, natural dyes and seed husks. These are partly water-soluble, partly only removable by an alkaline process. In some cases an acid treatment is necessary.
Seed husks and cotton waxes can only be eliminated by longer alkaline boiling or kier boiling. This process is important to improve the hydrophilicity (a must for continuous dyeing and printing). A boiling process is also useful to reduce the danger of a catalytic damage in a subsequent peroxide bleach.
Scouring / Alkaline Cracking
Textile Effects
Bleaching means, to destroy the natural dyestuff in the fibre.
There are two chemically different bleaching processes:
Oxidative bleaching with hydrogen peroxide, sodium hypochlorite, sodium chlorite or peracetic acid Reductive bleaching with stabilized hydrosulphite preparations and sulphoxylates.
The choice of chemicals depends on the required degree of whiteness, on technological and ecological aspects, on the machinery and on economic aspects.
Overdosing of the bleaching chemicals, insufficient temperature regulation, too long bleaching times, existence of catalysts, insufficient stabilizing, etc. may lead to damaging of fibers.
Bleaching
Textile Effects
Bleaching agents, e.g. hydrogen peroxide, are “stabilized” during manufacture. In bleach liquors which contain hydrogen peroxide, bleaching only occurs after activation, e.g. by the addition of alkali or/and by increased temperature.
This bleaching activity must be “regulated” to prevent rapid, spontaneous decomposition of the bleach and to minimize damage to the fibre, to avoid waste of bleaching chemicals as well as undesirable side reactions.
This process of regulation or control is also called as stabilization.
Processor / Stabilizer
Textile Effects
Tinoclarite CBB/G-I
PROCESSOR
INHIBITIONof
precipitations
ENCAPSULATIONand INACTIVATION
of catalysts /heavy metal ions
STABILITY in hot oxidizing
and alkaline bath
DISPERSINGof impurities
ACTIVATION andREGULATION of
bleachingactive peroxide
THRESHOLD EFFECTCPS principle
Textile Effects
Peroxide Killing
■ The leftover peroxide can cause serious problems in further reactive dyeing
■ The depth of certain dyes can be lost up to 40%
■ Turquoise, blues and reds are especially sensitive to peroxide
■ For peroxide killing either a reductive base product or a catalase enzyme based product can be used.
Textile Effects
Influence of peroxide on reactive dyeing
With Invatex PC Without Invatex PC
Textile Effects
Merckoquant® 1.10011.
Peroxide - Testanalytical test strips
O2 2-
MERCK 0 0.5 2 5 10
25mg/l H2O2
Residual peroxidein bath or on materialcan be tested withMerckoquant® test strips
no residual peroxidein bath
30 mg/l H2O2
in bath
5 mg/l H2O2
in bath
Rel. Depth 100 %
Rel. Depth 89 % Rel. Depth 76 %
Rel. Depth 100 %
WithoutCiba® TINOZYM® CAT
WithCiba® TINOZYM® CAT
Rel. Depth 100 %
Influence of peroxide on reactive dyes
Textile Effects
Bleaching agent: Derivate of sulphurous acids
sodium di-thionite (Na2S2O4)
stab. sodium di-thionitesodium bi-sulfite
Usually stab. sodium di-thionite (e.g. Ciba® CLARIT® PS) is used Application only efficient as pre- or subsequent bleach Low importance for cellulose fibers Use for PA and wool No full white possible
Reductive bleach
Textile Effects
Caustic concentration 270 - 330 g/l NaOH 100% (28-32 °Bé)Caustic temperature 15 - 20 °C (hot mercerization 60 - 90 °C)Reaction time 45 - 60 sec. (hot: shorter time)
Tension against shrinkageStabilizing up to about 50 g/l NaOH 100%Mercerizing wetting agent for quick and even wettingPretreatment raw, desized, boiled off, bleached
Mercerizing
Textile Effects
Mercerizing Effects
Increase in colour depth: By modification of the inner fibre surface, the number of absorption places for the dye uptake is increased. Depending on the class and type of dyestuff savings of up to 40 % are possible.
Covering immature and dead cotton:Fibres which died off before maturity, so-called dead cotton, as well as immature cotton which has been picked too early, form small knots during the spinning process. These knots are differently dyed or not dyed at all in the dyeing process. Mercerizing and a suitable selection of dyestuff can level out these differences.
Textile Effects
Mercerizing Effects
Dimensional Stability:The latent tensions in the fabric are eliminated. During the washing process after mercerization new hydrogen bonds are formed, which "set" the fabric. An optimal dimensional stability of the goods can only be obtained, if the alkali concentration in the fabric is decreased below 50 g/kg NaOH 100 %, before leaving the stabilizing zone.
Increase in tensile strength:Due to the transformed orientation of the cellulose chains in the cotton fibres their mechanical properties are changed. This leads to an improvement of the tensile strength. In the case of yarn mercerization the tensile strength may increase up to 40 %.
Textile Effects
Degree of desizing Water soluble / Residual fat content Hydrophilicity / rewetting effect Ca-, Mg-, Fe-content Degree of whiteness Remove of seed husk DP-value, fiber damage value pH value on the fabric Mercerizing effect
Assessment of the pretreatment effects: General
Textile Effects
Target: Assessment of the degradation degree of starch size
Procedure: Put fabric sample in iodine solution for about 1 min, short
washing out with cold water, dap with filter paper and
compare immediately with violet scale.
TEGEWA-Violet scale
Assessment of the pretreatment effects: Desizing
Textile Effects
Water extract
(2x20 min. after petrol
ether extract)
grey fabric 6 - 10 %
good desized < 0.7 %
moderate desized 0.7 - 0.9 %
Water extract
(2x20 min. after petrol
ether extract)
grey fabric 6 - 10 %
good desized < 0.7 %
moderate desized 0.7 - 0.9 %Reference for 100% cotton
Assessment of the pretreatment effects: Water soluble
Textile Effects
Assessment of the pretreatment effects: Residual fats
Petrol ether
extraction (3 h
extraction in soxhlet)
grey fabric 0.8 - 1.2 %
good scouring/bleaching < 0.4 %
moderate scouring/bleaching 0.4 - 0.6 %
Petrol ether
extraction (3 h
extraction in soxhlet)
grey fabric 0.8 - 1.2 %
good scouring/bleaching < 0.4 %
moderate scouring/bleaching 0.4 - 0.6 %
Reference for 100% cotton
Textile Effects
Several methods: TEGEWA-drop testWicking-test“modified wicking-test”
“modified wicking-test” (measurement of the capillary
rise)
time goodness of the hydrophilicity(sec/cm)
- 3 extremely high3 - 5 very good5 - 8 good, acceptable8 - process to be examined
“modified wicking-test” (measurement of the capillary
rise)
time goodness of the hydrophilicity(sec/cm)
- 3 extremely high3 - 5 very good5 - 8 good, acceptable8 - process to be examined
Reference for 100% cotton
Assessment of the pretreatment effects: Hydrophilicity
Textile Effects
Assessment of the pretreatment effects: Whiteness
Whiteness is a relative term , measured with the help of an instrument known as – SPECTROPHOTOMETER
The instrument helps to measure the reflectance data of the substrate ( without color) and using this data in formulas coverts it into various whiteness readings such as :
GanzCIE
StensbyBergerISO/Tappi .. etc
Textile Effects
Assessment of the pretreatment effects: pH value
The pH value of textile material is determined by the extraction into a neutral medium – 0.1M KCl and then checking on the pH meter .
Alternately the pH on textiles can also be checked by dropping a drop of universal indicator & immediately matching the color obtained with the standard scale .
Textile Effects
Assessment of the pretreatment effects: Iron content
The iron content on textiles can be determined qualitative by spotting with nitric acid + pottasium thiocyanate .
The presence of iron will be indicated by the appearance of a red color. The higher the intensity of the the coloration more is the amount of iron present.
calcium / iron
magnesium
grey 600 - 2500 ppm 10 - 100 ppm
good pretreatment < 300 ppm < 10 ppm
calcium / iron
magnesium
grey 600 - 2500 ppm 10 - 100 ppm
good pretreatment < 300 ppm < 10 ppm
Textile Effects
Assessment of the pretreatment effects: Residual peroxide
The residual peroxide on the textile material can be evaluated by spotting with 0.1M Titanum Chloride . The orange coloration in presence of hydrogen peroxide is the matched with the T scale .
The reading of which will immediately give approximately the mg of H2O2/ kg of fabric.
Textile Effects
Relaxation
Heat-setting
Scouring / Bleaching
Dyeing / Printing / Finishing / Whitening
Typical process route for Typical process route for
ElastaneElastane
Textile Effects
Typical process route for LyocellTypical process route for Lyocell
Woven goodsWoven goods
Singeingwide
Desizingwide
+/- Bleachingwide
+/- Singeingwide
Fibrillationrope
Defibrillationrope
Dyeingrope / wide
Finishingrope / wide
T-I-O Processwide
+/- Caustifyingwide
Knit goodsKnit goods
Pre-washrope
+/- Bleachingrope
Fibrillationrope
Defibrillationrope
Dyeingrope / wide
Finishingrope / wide
+/- Defibrillation
rope
Textile Effects
Cotton Linen/flax
cellulose 90 – 95 % 60 – 65 %
pectines/hemicelluloses 1 – 5 % ~ 20 %
lignins - ~ 3 %
waxes ~ 0.6 % ~ 1 %
watersoluble parts ~ 2.5 % ~ 12 %
With cellulose representing more than 90% of the total fiber composition, cotton is a relatively pure raw product in contrast to linen, which contains only around 60% cellulose. Many more impurities need to be removed from linen.
Linen / flaxAdjacent substances
Textile Effects
Objectives
Removal of:- sizes- incrustations- alkaline earth and heavy
metal ions High degree of whiteness Good hydrophilicity High fiber protection Reproducibility well-balanced cost-benefit ratio Consideration of environmental
aspects
Objectives
Removal of:- sizes- incrustations- alkaline earth and heavy
metal ions High degree of whiteness Good hydrophilicity High fiber protection Reproducibility well-balanced cost-benefit ratio Consideration of environmental
aspects
Possible pretreatment steps
Enzymatic Desizing/Cracking
Alkaline Cracking Oxidative Cracking Acid Cracking Peroxide Bleach (+/-
silicate) MEGA Bleach Hypochlorite/Chlorite
Bleach Mercerizing
Ammonia treatment
Possible pretreatment steps
Enzymatic Desizing/Cracking
Alkaline Cracking Oxidative Cracking Acid Cracking Peroxide Bleach (+/-
silicate) MEGA Bleach Hypochlorite/Chlorite
Bleach Mercerizing
Ammonia treatment
Linen / flaxObjectives / Pretreatment steps
Textile Effects
Soft handle Harsh handle (e.g. dress goods /drapery) (e.g. table cloth)
1 – 2oxidative bleaches
2 – 3oxidative bleaches
2 – 4oxidative bleaches
treatment with NaOH
+ Cracking Agent
treatment with soda ash
+ Cracking Agent
Pretreatment processes for linen / flax
Textile Effects
grey material
Acid Cracking + Peroxide Bleach whiteness Berger 30
Alkaline Cracking + Peroxide Bleachwhiteness Berger 47
Peroxide Bleach + Peroxide Bleach whiteness Berger 53
Acid Cracking + Chlorite Bleach whiteness Berger 73
+ Peroxide Bleach
grey material
Acid Cracking + Peroxide Bleach whiteness Berger 30
Alkaline Cracking + Peroxide Bleachwhiteness Berger 47
Peroxide Bleach + Peroxide Bleach whiteness Berger 53
Acid Cracking + Chlorite Bleach whiteness Berger 73
+ Peroxide Bleachmaterial: 100% linen rovecountry: Lithuania
material: 100% linen rovecountry: Lithuania
Bulk trialsCirculation apparatus
Textile Effects
Aim removing of
Washing to remove Dirt and extrenous matter Degumming Oxidative Bleaching Reductive bleaching
Principle The washing is done
in discontinuous or continuous machinery as detergent or solvent scouring
Aim removing of
Washing to remove Dirt and extrenous matter Degumming Oxidative Bleaching Reductive bleaching
Principle The washing is done
in discontinuous or continuous machinery as detergent or solvent scouring
Pretreatment of Silk
Textile Effects
22%
9%
21%
48%
grease suint sand, dirt, nat. impurities wool fibre
wool type: superfine merino
WoolWoolRaw wool - impurities (example)Raw wool - impurities (example)
Textile Effects
Washing / scouring
Crabbing / potting
Milling
Carbonizing
Chlorinating
Bleaching(oxidative, reductive)
WoolWoolPretreatment processesPretreatment processes
Textile Effects
Typical process route for viscoseTypical process route for viscoseg
rey s
tate
dyein
g,
pri
nti
ng
, fi
nis
hin
g Washing/Desizing
Washing/Desizing Caustifying
Caustifying Washing
Washing/Desizing Caustifying Bleaching
VISCO-COMBI-BATCH Washing
Textile Effects
combines the conventional sequence of processing:
Desizing (oxidative)
Cleaning (removal of spinning oils and preparations)
Bleaching
Caustifying
VISCO – COMBI – BatchAn ace in Ciba preparation
Textile Effects
A combination of different steps (desizing - caustifying -
bleaching)
which results in a considerable rationalization of water
consumption,
energy and time
No special separate machinery is required
Extremely clean fabric with a very good removal of all
disturbing
residuals such as size, oils, waxes, sulphuric components,
inorganic and metallic impurities, ….
Avoidance of folding and creasing as it is an open-width
batching process
An almost complete caustifying effect in terms of color yield
enhancement
can be obtained while safeguarding a soft and bulky handle
Benefits of the VISCO – COMBI – Batch
Textile Effects
PB ENZ PB CPB VCB VCB with silicate/16h 16h
16h
Ciba® TINOZYM® AL g/l 10 - - -
Ciba® ULTRAVON® CN g/l 5 5 5 5Ciba® INVATEX® CRA g/l - 3 3 3Ciba® TINOCLARITE® BS g/l - 5 -
-Ciba® TINOCLARITE® CBB g/l - - 12
12silicate 38°Bé ml/l - 8 - -NaOH 100% g/l - 10 40 40H2O2 35% ml/l - 30 10 30
Color Strength in %Printing - green (reactive) 100 82 130 105 - orange (reactive) 100 88 124 115 - brown (reactive) 100 86 142 128Dyeing - red (direct) 100 92 113 110 - blue (reactive) 100 108 131
128
Color yield improvement on viscoseAfter different processes