DYEING MECHANISM

, --. . ,

--_._-_____.. _.

* EXHAUSTION

* ABSORPTION

* DIFFUSION

* MIGRATION

* FIXATION

i i

DYEING MECHANISM

AFFINITY -> DYEDISSOLVED <- -' DYEFIBER

SOLUBILITY DYE^^^^^ <-

DYE IN DYEBATH <- CONVECTIVE DIFFUSION ->

DYE I N BOUNDARY LAYER <- MOLECULAR DIFFUSION ->

DYE ON FIBER SURFACE <- DIFFUSION IN FIBER ->

I F f" fl ids

DYE I N FIBER C- FIXATION/CHEMICAL REACTION ->

IMMOBILIZED DYE

DYEING MECHANISM

A F F I N I T Y -> DYEDISSOLVED '- -> DYEFIBER

SOLUBIL ITY DYESOLID

S P E C I F I C AFFINITY OF THE DYE FOR THE F IBER BY HYDROGEN BONDING, VAN DER WAALS FORCES, OR I O N I C INTERACTION WHICH MAY OCCUR AT SPECIF IC SITES, BY ELECTRICAL EFFECTS OR THE FORMATION OF BONDS.

MECHANICAL ENTRAPMENT OF THE DYE WITHIN THE FIBER, ESPECIALLY BY ( qc Ais L A L ) RENDERING THE DYE INSOLUBLE BY CHHEMICAL

REACTION ( I N WHICH THE FIBER MAY OR MAY NOT PARTICIPATE).

BINDERS HOLD PIGMENTS I N PLACE ON THE F IBER SURFACE.

i

DYEING MECHANISM

SOLUBILITY -> DYEDISSOLVED <- DYEFIBER DYESOLID <-

DYEING MECHANISM DYESTUFF/FIBER EXAMPLE

SIMPLE D I S T R I B U T I O N DISPERSE/SYNTHETIC

S P E C I F I C A F F I N I T Y ACID/WOOL ACID/NYLON BASIC/ACRYLIC DIRECT/CELLULOSIC

ENTRAPMENT VAT/ C ELLU LOS I C SULFUR/CELLULOSIC NAPHTHOL/CELLULOSIC

- 7 F I B E R REACTIVE/CELLULOSIC

BINDING PIGMENT/ALL FIBERS

DYEING MECHANISM

0 0

dyebath cellulose

equilibrium = [F]bath -+ + [FlCel

substantivity \ = p( [[kk!h) i i

I

General Fixation Characteristics of Major Dyeclasses

Basic Dyes

Metal Complex Dyes

Azoic Dyes

Acid Dyes

Disperse Dyes

Vat Dyes

Direct Dyes

Reactive Dyes

Sulphur Dyes

0 20 40 60 80 I 0 0

General % Fixation

ECG017

Ideal Exhaustion Rate Maximum Total Exhaustion Split Salt Addition =

Temperatur 1 'e e 00 90 80 70 60 50 40 30 20 I O 0

I C - - YQ EX

0 20 40 60 80 100 120 140

iaustion

Time Minutes

- TimelTemperature L-1 ....,.......... >,.>:.>,,., .......,,/ ....A . . . O/o Dye Exhaustion

Substantial increase in cotton consumption in recent years

Concern about some technical/ environmental drawbacks of alternative dyeing methods

Strong demand for bright and deep shades

Convenient, economical dyeing methods

i

2-

equilibrium

1 OH- absorption in fibre

hydrolysis in bath hydrolysis in fibre

OH-

equilibrium

C EL-f i bre amQb R(eactive) system

I Chromophore 1

fibre - dye bond 1 OH-, H', oxydants

bond hydrolysis

dye affinity

dye concentration \

liquor ratio

type of fibre

z PH

electrolyte concentration

temperature \

I i

Cellulose in water carries a negative charge on its surface. Reactive dyes also carry a negative charge leading to a natural repulsion between dye and fibre.

. .... ..... ~ L., ::. .. .j., ., ..:::.. ,,,,,

‘4 . ..... ....

Addition of inert electrolytes such as common salt (NaCI) or Glauber’s salt (Na,SO,) suppresses the electrostatic repulsion between dye and fibre.

i

Washing-Off mechanism of Reactive Dyes ... ..

Removal of unfixed hydrolysed dye, salt, alkali, auxiliaries from fibre surface

Removal of unfixed hydrolysed dye, salt, alkali, auxiliaries from fibre inside

PHASE I Favourable conditions:

high number of bath changes high liquor ratio in each bath strong mechanical agitation of bath (high speed of bath circulation)

t,: ; '6 .-. (4 0 > . < *Ld dye 0 unfixed, hydrolysed dye X chemicals

ECARE8

PHASE 2 Favou ra ble conditions:

high temperature of bath low amount of unfixed, hydrolysed dye low electrolyte concentration in the bath factors (low water hardness) high liquor ratio ineacniath = high

gradient high number of bath changes and of course low affinity, small dyestuff molecule main with high diffusion factor

main

The Cibacron Approach

hot dyeing systems warm I cold dyeing systems

all range names mentioned are registered trademarks of the respective producers

(Procion MX)

(Levafix EA, Drimarene RIK)

(Levafix E)

(Cibacron F, Levafix EN)

(Cibacron LS)

(Cibacron C)

(Cibacron E, Procion H/HE) (Sumifix Supra, Basilen FM) .

(Drimarene X) increasing reactivity

via R1

via R2

/-

...... ..____

B ridg elbridge

Headlhead

Headltail

R1 R2

- R1- R2

R I - R2

Headlbridgel tail

R1 2 R3

R I Headlheadl tail

R2 R3

R = reactive group

i

, , ._ , ~ ~En”iro.ca.r-e--6~ _ _ . . . . . . . . . .. . . . . .. .. . . . .I_....ii___ . . . . . . . .. . . . . . . ..

Re- leased

1957

1970 -

1957

1970 -

1980

1984

Reactive groups

MCT I MCT

vs I vs

MCT I VS

COOH N

C u rre n t ma n u fact u re r( s), trade name(s)

IC1 Procion H-E Ciba Cibacron E etc.

(part of the ranges)

~~ ~~

Hoechst Remazol (two dyes, mainly: Remazol Black 6 )

Sum i tom0 Sumifix Supra Hoechst Remazol S

(2 dyes)

Nippon Kayaku Kayacelon React

“bridge”

“ headhail”

“ h eadl h ead”

“ bridge”

Uses ( p referred)

- exhaust (8OOC)

- pad-batch - pad-dry-pad-steam - exhaust (40° - 6OOC)

- exhaust (6OOC)

- exhaust (>lOO°C) (1 3OoC for PES/ CO)

all range names mentioned are registered trademarks of the respective producers

(continued)

leased

1993

1994

_ _ _ _ _ ~

Reactive groups

MCT / VS / VS FT / VS arom FT / VS aliph

FT I FT vs / vs vs / vs

MCT I VS

FT/FT MCTNSNS

Current man ufac tu re r( s), trade name(s)

Ci ba Cibacron C

BASF Basilene FM (4 dyes)

Ci ba Cibacron LS

mainly: “headlhead”

also: “bridge” (1)

‘I headltail” (I)

“headlhead” or

” bridge” or

“headlbridgel tail”

“bridge” or

“headlbridgel tail”

Uses ( p referred)

~~ _ _ _ _ _ ~ ~ _ _ _ _ _ _ ~

- pad-batch - pad-dry-pad-steam - low liquor ratio

exhaust (50° - 6 O O C ) - pad -direct-steam

- pad-batch - pad -d ry-pad -s tea m - exhaust (6OOC)

- exhaust (7OOC)

all range names mentioned are registered trademarks of the respective producers

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- __-_--

I VS bireactive dyes:

>

Efforts to fix the (already formed) bond between the VS and the fibre. An unstable situation arises involving fixation and hydrolysis at the same time.

component endangers the

I vs

S

Thus any pH acceptable for fixation of the VS group is high enough to fix the

The fragile VS-fibre bond is not endangered unnecessarily. group as well.

x

Z (v

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,Degree of Fixation - nvl

. . . ... __-

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Dye = R I

H y d x Fixation

Dye-OH Dye-R-OCel

, --

_...,. ....... _..-..

R1 - Dye - R2 I

Hydrolysis Fixation 75c---- 75%

v v CelO-Rl-Dye- R2

HO - Dye - R2

Hydrolysis I Fixation

f

HO-Dye-OH HO-Dye-RZ: -0Cel

The Cibacron Approach

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Cibacron C, Degree of Exhaustion and Fixation

. . . . I

2 % dyeings on CO n.merc., Liquor rafio 6: l

Yellow C-R-01

Orange C-G

Red C-2G

Red C-R

Blue C-R

Navy C-B 00%

EcareSr

Yo OOC 06 08 OL 09 OS OP OI 02 OC O

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ClBACRON@C in a Nutshell

Two (or three) reactive groups yields: for fast diffusion facilitates:

D Small and I or flexible molecules

High Fixation @ Washi ng-off 3 Resistance to Hydrolysis GI Levelling

> Optimized pair of reactive groups ensures homogenious dyeing properties in: ensures:

D Highly soluble chromophores and I or reactive systems

0 Reactivity Ease of Use o Affinity 2 Solubility 0 Levelling

0 Reproducibility (no dye precipitation)

’’\> Low I medium affinity chromophores Compact range ensures: ensures: QEase of Use

C Fast Diffusion c Low Risk of Tailing

oLess Human Error

ECare17r

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Washing-Off Properties of Cibacron C Dyes . ............ . _..._ __._..ll........ __ ..-----

Very Low Propo of Unfixed Dye

(in Fibre and Bath) Extraction of Unfixed

ECARE3 The Cibacron Approach

7

Daphnia pulex Sodium chloride LC 50 2373 ppm Sodium sulfate LC50 2765 m m

Gambusia affinis Sodium sulfate Morone saxalitis (larvae) Sodium sulfate

LC 50 120 ppm LC50 250ppm . .

LC 50 = 50% mortality in test (exposure 24 - 96 hours) LC 0 = Highest limit without mortality

Morone saxalitis (a few cm) Sodium sulfate LC 50 3500 ppm . I

Salmo gairdneri Sodium sulfate Lepomis macrochirus Sodium sulfate

I .

LC 0 750ppm LC 0 8700 ppm

.pj]gI&Q a &

dyeing of cotton and viscose with reactive dyes

/-- ,* q Q:/yJ$T d

dyeing of cotton with direct dyes effluents from ion-exchangers (used to soften process water) application of FWAs on cellulosic fibres cutting-agents for standardization of some dye ranges levelling agents in dyeing of PAC and wool dyeing of cotton with some vat, sulphur or naphthol dyes

0 ;p,&q))t a

35 tons/ day of cotton (knit) 6 days/ week schedule 30 Yo bleached white /70% dyed I O : 1 average liquor ratio (exhaust dyeing) I 8 gallons of water per pound of treated fabric reactive dyes daily effluent volume: > 1.3 million gallons

Q) eh@ a

2500 DDm I I if 60 g/l electrolyte is used (medium to deep shades)

(>3500 rmm 1 . 1 . when black/ navy is dyed)

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/- fj uorotriazine g rou p a

d e activated medium reactivity stable fibre-dye bonds (alkali, chlorine, peroxide) bonds stable to acid, thanks to two groups

igh solubility

/

exclusive patented' bridge

gives molecule good flexibility selected for maximal sol u b i I i ty

F

contribution to high

high color strength possibility to improvi fastness or shade

affinity

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* 1/11 SD, CO non-merc., actual dyeing conditions

gll salt 120

100

80

60

40

20

0

Averages with a similar production volume

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