mercerization or how a traditional process can reduce … mercerization or how a traditional process...

1

Mercerization or how a traditional process

can reduce the environmental impacts of a shirt

S. Pesnel, V. Pasquet, A. Perwuelz - GEMTEX laboratory, ENSAIT, France

GEMTEX: university research laboratory in the field of textile materials and processes

D. Hazard, C. Dupuich - VERAMTEX S.A., Belgium

www.acvtex.eu

6 - 7 November 2012 - Lille

PRÉFET DE LA

RÉGION NORD –

PAS-DE-CALAIS

2

Summary

Mercerizing

Tests in laboratory

Dyeing

Use phase

Lifetime

LCA

3

Mercerizing

Mercerized fabrics :

is dyed more easily

MANUFACTURING

OF THE SHIRT

COTTON

PRODUCTION

USE PHASE

END OF LIFE

Spinning

Weaving

Sewing

Washing (60°

Influence of mercerizing

Life cycle of a shirt

C)

Lifetime

Drying (tumble dryer)

Ironing

Actions on

use phase

and lifetime

2 effective levers to reduce

environmental impacts of textile products

Mercerizing ?

Optional treatment during the manufacture of cotton textiles

Changes the macromolecular organization of cellulose

Mercerizing

Dyeing

dries faster

creases less

has a better quality

4

2 processes of mercerizing

→ with NaOH or with NH3

Traditional process with soda (NaOH)

Pre-washing Impregnation Stabilization Soda recovery Neutralization

washing

Alternative process with liquid ammonia (NH3)

NH3 impregnation NH3 evaporation

Washing x 2

Industrial data

Recycling of NH3 (more than 99%)

Assumption:

NaOH is 70%

recycled

Different influence:

on the fabrics

on the life cycle

5

Objective of the study

Tests in laboratory on the 3 fabrics

to evaluate differences on:

Dyeing step

Use phase

Lifetime

Comparative LCA between 3 shirts:

a untreated shirt

a NH3 mercerized shirt

a NaOH mercerized shirt

MANUFACTURING

OF THE SHIRT

COTTON

PRODUCTION

USE PHASE

END OF LIFE

Dyeing

Spinning

Weaving

Sewing

Washing (60°

Lifetime

Mercerizing

Influence of mercerizing


C)


Ironing

6

Tests in laboratory

Dyeing

Principle:

Application of the same dyeing processes on the 3 fabrics

Study of the color obtained MANUFACTURING

OF THE SHIRT

COTTON

PRODUCTION

USE PHASE

END OF LIFE

Dyeing

Spinning

Weaving

Sewing

Washing (60°

Mercerizing


C)


Ironing

Best color strength with NaOH mercerized fabric

Less dye is necessary for this fabric

Only 3.5% of dye

8.5% of dye for the untreated fabric

7% of dye for the NH3 mercerized fabric

7

Tests in laboratory

Use phase (drying and ironing)

Measurements are realized to quantify the differences

between the 3 fabrics concerning the drying and the

ironing MANUFACTURING

OF THE SHIRT

COTTON

PRODUCTION

USE PHASE

END OF LIFE

Dyeing

Spinning

Weaving

Sewing

Washing (60°


C)


Ironing

Mercerizing Drying

Measure of the residual moisture on the

3 fabrics after washing

Slight decrease in the amount of

moisture with mercerized fabrics (5%)

Reduction of time in the tumble dryer

Ironing

Time reduction of 40%

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Tests in laboratory

Lifetime

Evolution of tear strength

MANUFACTURING

OF THE SHIRT

COTTON

PRODUCTION

USE PHASE

END OF LIFE

Dyeing

Spinning

Weaving

Sewing

Washing (60°


C)


Ironing

Lifetime

Mercerizing

Tear strength (N)

0

2

4

6

8

10

12

0 50 100 150 200 250 300

Washing and drying

Untreated fabric

NH3 mercerized fabric

NaOH mercerized fabric

Polynomial (NH3

mercerized fabric)

Polynomial (Untreated

fabric)

Polynomial (NaOH

mercerized fabric)165

Mercerizing

inreases the

lifetime by

50%

Evaluation of the degradation of

shirts during washing :

x 250 Fabrics are washed and dried in

tumble dryer during 250 cycles

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LCA

Scope definition

Functional unit:

“use and wash a shirt during one day”

Assumptions:

the shirts weights 200g

shirts are washed after each use

drying in tumble dryer

System boundary

Calculation of the impacts:

ReCiPe method (midpoint)

Software :

GaBi (PE International AG)

Data sources :

GaBi software, ELCD and EcoInvent databases in

general

Experimentation, publications and industrial data

for more specific processes

MANUFACTURING

OF THE SHIRT

COTTON

PRODUCTION

USE PHASE

END OF LIFE

Dyeing

Spinning

Weaving

Sewing

Washing (60° C)


Ironing

Mercerizing

10

LCA

Results for all the life cycle

Mercerized fabrics are

less impacting

→ mainly due to lifetime

(evaluate with tear

strength)

Fossil depletion [kg oil Equiv.]

-0,002

0

0,002

0,004

0,006

0,008

0,01

0,012

0,014

0,016

0,018

Untreated NaOH NH3

End-of-lifeUse phaseShirt productionCotton production

Climate change [kg CO2-Equiv.]

0

0,01

0,02

0,03

0,04

0,05

0,06

Untreated NaOH NH3

End-of-lifeUse phaseShirt productionCotton production

Ionising radiation [kg U235 Equiv]

-2,0E+04

0,0E+00

2,0E+04

4,0E+04

6,0E+04

8,0E+04

1,0E+05

1,2E+05

Not

mercerized

shirt

NaOH

mercerized

shirt

NH3

mercerized

shirt

Cotton production Shirt production

Use phase End-of-life

Photochemical oxidant formation

[kg NMVOC]

-2,0E-05

0,0E+00

2,0E-05

4,0E-05

6,0E-05

8,0E-05

1,0E-04

1,2E-04

1,4E-04

Not

mercerized

shirt

NaOH

mercerized

shirt

NH3

mercerized

shirt



Untreated NaOH NH3 Untreated NaOH NH3

Climate change [kg CO2-Equiv.]

0

0,01

0,02

0,03

0,04

0,05

0,06

Untreated NaOH NH3



Use phase is the most

polluting step

Drying: 40-57% of the

impact of the use

phase

→ hypothesis:

“systematic use of a

tumble dryer”

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LCA

Results for shirt production and use phase

- Use phase of mercerized

shirts are less impacting

→ shirts dry faster and crease

less (ironing time is shorter)

Use phase

80%

85%

90%

95%

100%

105%

Fossil

depletion

Climate

change

Untreated

NaOH

NH3

Shirt production

94%

96%

98%

100%

102%

104%

106%

108%

Fo

ssil

de

ple

tio

n

Clim

ate

ch

an

ge

Ion

isin

g

rad

iatio

n

Ph

oto

ch

em

ica

l

oxid

an

t fo

rma

tio

n

Not mercerized shirt NaOH mercerized shirt NH3 mercerized shirt

Use phase

80%

85%

90%

95%

100%

105%

Fo

ssil

de

ple

tio

n

Clim

ate

ch

an

ge

Ion

isin

g

rad

iatio

n

Ph

oto

ch

em

ica

l

oxid

an

t fo

rma

tio

n

Not mercerized shirt

NaOH mercerized shirt

NH3 mercerized shirt

- Production of mercerized

shirts is more polluting due

to the additional step

→ NaOH mercerizing is

more impacting

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Conclusion

Study of the degradation of the shirts during washing

→ to quantify the lifetime improvement with mercerised shirts.

Mercerizing:

significant increase environmental impacts during the production phase

but net environmental benefits on the all life cycle of a shirt

Future works :

Evaluation of the lifetime with additional parameter (in addition to the tear strength)

→ ex: tensile strength, abrasion resistance

Scenarios including real use of shirts, air drying and systematic ironing

→ evaluation of the new lifetime

Soda is recycling (70%) for NaOH mercerizing

→ in practice it is not systematic → sensitivity analysis

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Thank you for your attention.

Projet ACVTEX

www.acvtex.eu

Sandrine Pesnel, GEMTEX / ENSAIT

[email protected]

www.acvtex.eu

PRÉFET DE LA

RÉGION NORD –

PAS-DE-CALAIS

mercerization or how a traditional process can reduce … mercerization or how a traditional process...

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