Reactive basics. slides

World production of fibres 2000

CELL

PES

PA

PAN

Wool

Others

37%

32%

2% 16%

8%

About 52 Mio tons of which CEL 19 Mio tons PES 17 Mio tons

5%

Dyes for CelluloseDyes for Cellulose

Reactive

Vat

Subst.

Indigo

Sulfur

Naphtol

Pigments

7%

12%

8%2%

2%

60%or 1.8 bio CHF

9%

Worldwide market 2001Worldwide market 2001: : 33 billions CHF billions CHF

Superficial indigo ring dyeing of cotton typical of denim

Vat dyes

Sulfur dyes

Diazo- or Naphtol dyes

BASICS OF REACTIVE DYEING

ABSORBTION AND DIFFUSION OF DYE IN FIBER• SUBSTANTIVITY: INFLUENCING PARAMETERS• SPEED OF DIFFUSION: INFLUENCING PARAMETERS

REACTION OF DYE WITH FIBER • SPEED OF REACTION: INFLUENCING PARAMETERS• PARASITIC REACTION. DYE INACTIVATION• BI-REACTIVE DYES

WASHING OFF UNFIXED DYES• PARAMETERS INFLUENCING SPEED OF WASHING OFF

Adsorbtion of dyes on cotton surface

Reactive dyes

The 3 phases of reactive dyeing

Substantivity of reactive dyes

Parameters influencing substantivity

The electron system between dye and fiber

Number of double bonds vs. Affinity

Rupture of double bond system = Affinity loss

Cellulose and dye : both have negative charge !

Overcoming the repulsion : Electrolyte screens

Effect of pH on negative load of fiber

Effect of dye concentration on substantivity

Dye adsorbtion on surface

Substantivity: Function of dye conc in CEL & bath

Effect of temperature on substantivity

Effect of liquor ratio on substantivity



Summary : Parameters affecting substantivity

Substantivity increases with:

•Increasing Standard Affinity of the dye

•Increasing electrolyte concentration in the dye bath

•Decreasing pH in the dyebath

•Decreasing dye concentration in the dyebath

•Decreasing dyeing temperature

•Decreasing Liquor Ratio

Dye diffusion inside the fiber

Dye diffusion inside the fiber

Substantivity is only one of many diffusion-influencing parameters!

Fibre type (mercerized-, causticized-, non-mercerized cotton, viscose)

Dyeing temperature

Size and shape of the dye molecule

Substantivity of the dye

Electrolyte concentration in the bath

Dye concentration

The speed of diffusion of reactive dyes depends mainly on:

Various CEL structure models

Various CEL structure models

Dye diffusion in the fibre

CEL has heterogeneous structure

Comparison: Un-mercerized vs mercerized cotton

Effect of temperature on dye diffusion

Effect of dye molecule size on diffusion

Effect of dye substantivity on diffusion

Effect of electrolyte on diffusion

Summary: Parameters influencing Diffusion

The speed of diffusion of reactive dyes can be increased by:

Raising the dyeing temperature

Reducing the size and bulkiness of the dye molecule

Reducing substantivity of the dye in the dyebath

Causticizing or mercerising the cellulose





Exhaust process: Separated diffusion & fixation

Pad dry pad steam: Separated diffusion & fixation

“All-in“ Exhaustion: combined diffusion & fixation

Danger !!

Pad Batch: combined diffusion & fixation

A: Nucleophilic substitution reaction

B: Nucleophilic addition reaction

Reactivity: Speed of reaction

Inactivation reactions: competing with fixation

Inactivation reactions. Competing with fixation

First release

Reactive Group Inventor Used in Reactivity 5=>1

High=>low

Main usage

1956

Dichlorotriazine (DCT)

ICI PROCION MX 5 Pad batch

1956

Monochlorotriazine (MCT)

ICI

CIBA

PROCION HE, HEXL

CIBACRON E clones many

bireactive dyes

2 Exhaust (hot) Pad thermofix

Printing

1957

„Para Vinylsulfone“ (VS)

HOECHST

REMAZOL clones

Many bireactive dyes

3

Pad batch

Pad dry

Pad steam

Exhaust (warm)

Printing

NH

NN

N

Cl

Cl

R

NH

NN

N

R'

Cl

R

SO

O

OSO3H

NH

R

Commercial reactive groups

First release


High=>low

Main usage

1960

Trichloropyrimidine

GEIGY HOECHST

CIBACRON TE 1 Exhaust (hot)

1961

Dichloroquinoxaline (DCQ)

BAYER LEVAFIX E 4 Exhaust (warm)

1971

Difluorochloro-pyrimidine (DFCP)

BAYER SANDOZ

LEVAFIX E-A

DRIMARENE K

some bireactive dyes

4 Exhaust (warm)

NH

NN

Cl

Cl

R

Cl

N

N

Cl

Cl

O

NH

R

NH

NN

F

F

R

Cl


First release


High=>low

Main usage

1978

Monofluorotriazine (FT)

CIBA

CIBACRON F

Many bireactive dyes in

CIBACRON C, FN, CIBACRON

LS, H

4 Exhaust (warm)

Exhaust (hot)

All pad process

1980

„Meta Vinylsulfone“ (VS)

SUMITOMO

SUMIFIX SUPRA bireactive dyes

Clones3 Exhaust (warm) Pad

batch

Pad dry

Pad steam

1985

Alkylsulfatoethylsulfone (VS)

CIBA

Many bireactive dyes in

CIBACRON C and CIBACRON

FN especially

3 Exhaust (warm)

All pad process

NH

NN

N

R'

F

R

NH

RS

OO

OSO3H

(Aliph)NH

RS

OO

OSO3H


First release


High=>low

Main usage

1985

Alkyl-Arylsulfatoethylsulfone (VS)

CIBA

Many bireactive dyes in CIBACRON

C and CIBACRON FN

3 Exhaust (warm)

All pad process

1997

Difluoropyrimidine (DFP)

CLARIANT DYSTAR

Used in bireactive dyes

in DRIMARENE

HF

LEVAFIX CA

4 Exhaust (warm)

All pad process

(Aliph)NH

O

NH

R SO

O

OSO3H

NH

NN

F

F

R


Influence of reactive group on speed of reaction

Reactivity of the group says nothing about stability of the bond with cellulose!

Influence of reactive group on speed of reaction Complete, reproducible

Incomplete!

Influence of reactive group on speed of reaction

Influence of chromophore and substituent on speed of reaction

„Inductive effects“ on reactive group :„pumping in“ or „pumping out“ electrons

Influence of chromophore on speed of reaction

Factor 30 !

Influence of Substituent on speed of reaction

• Scarlet chromophore• Fluorotriazine group• 3 different substituents

Cellulose model

Cellulose model

Site of reaction: ionized alkohol group

Site

Effect of pH on cellulose ionization

Effect of pH on speed of reaction

Example: Reactive group DFCP

Nucleophilic addition: Reaction mechanism of vinylsulphone dyes

Effect of temperature on speed of reaction

Effect of substantivity on speed of reaction

High substantivity

Low substantivity



Summary: Parameters influencing speed of reaction.

Speed of reactions depends on:

• Reactivity of the reactive group

• Inductive effects of the chromophore on reactive group

• Inductive effects of the substituent of the reactive group

• pH of the dyebath (Reaction speed increases when pH increases)

• Temperature of the dye bath ( reaction speed increases as temperature rises)

• Substantivity of the dye in dyebath

Bireactive dyes: Effect on degree of fixation

Bireactive dyes : structures

Mono-reactive dye A

Poor stability of the bond, to acid

Mono-reactive dye B

Poor stability of the bond, to alkali

Bi-reactive dye C

Bond is stable to both acid and alkali

Bi-reactive dye: possible impact on substantivity

Comparison between bi-reactive MCT/VS and FT/VS dyes

MCT/VS• MCT has lower speed of

reaction with CEL than VS• MCT requires a higher pH than

VS for complete fixation• Bond of MCT with CEL is stable

in alkaline dyeing conditions• Bond of VS with CEL is unstable

in alkaline dyeing conditions

Thus:Higher dyeing pH necessaryto fix MCT: may distroy VS

bondorLower pH, safe enough for VS:allows only part fixation of

MCT

FT/VS• FT has higher speed of

reaction with CEL than VS• FT does fix completely at ideal

pH of fixation for VS and at lower pH

• Bond of FT with CEL is stable in alkaline dyeing conditions

• Bond of VS with CEL is unstable in alkaline dyeing conditions

Thus:The (low) pH, best suitable

forcomplete fixation of VSwithout significant

destructionof the VS bond, also warrantscomplete fixation of FT

Comparison between bi-reactive MCT/VS and FT/VS dyes

Although the MCT/VS combination has led toseveral good dyes, it suffers from a basic

problem :

Potential for reproducibility issueschoice between 2 risks • of incomplete fixation of MCT or• of hydrolysis of the just formed bond, in

dyeing phase

Destruction of the bond between fiber and dye

Reactive dyes as ion exchangers

Bond destruction : triazine & pyrimidin dyes

Bond destruction: vinylsulphone dyes

Acid bond destruction: Triazine & pyrimidine dyes

Alkaline bond destruction: Vinylsulphone dyes

Oxidative bond destruction: Pyrimidine dyes

Oxidative bond destruction: Pyrimidin dyes

Summary: Stability of the dye –fiber bondStability of dye/fibre bond Tendency

In alkaline media MCT, FT, DFCP, DFP better than VS, DCQ

In acid media VS better than DFCP, FT, MCT, DCQ, DFP

In per-borate containing media

MCT, FT, VS better than DFP, DFCP, DCQ

In chlorine-containing media (1-5 ppm)

MCT, FT, VS better than DFP, DFCP, DCQ





Why is it necessary to wash-off unfixed dyes ?

Because ,

even small quantities of unfixed dye

remaining inside the fiber

lead to poor wash fastness (bleed)

in usage of the textile

TD 4.5 CTS Exhaust CEL & CEL/PES 02/98 cc-fn12.ppt

Washing fastness test on multifiber band

Performance with short washing off procedure:(CIBACRON FN procedure as described above)

Washing C4A

....Simulating bleed problems in household washing

Two different phases of washing off:

Extraction of unfixed dye from outside the fiber Quick process, no need for high temperatureIs only a dilution

Extraction of unfixed dye from inside the fiberVery slow processRequires diffusion of dye molecule inside->out of fiberAll parameter favoring diffusion speed, are favorable to good washing off

PARAMETERS AFFECTING THE WASHING OFF PROCESS

• Amount of unfixed dye which must be extracted from fiber depends on shade depth, degree of fixation of dye, substantivity in dyebath

• Speed of diffusion of the dye in the washing off bath depends on size of dye molecule, substantivity in washing off bath and temperature of washing off bath

• Washing off equipment Especially number of successive wash baths, strength of flow,

• Substantivity of the dye under the fastness test conditions

Washing off unfixed dyes

Slow diffusion & high substantivity dye type

Washing off unfixed dye

Quick diffusion &low substantitivity dye

Washing off unfixed dye

Slow diffusion & low substantivity dye

Technology

Reactive basics. slides