1

Sol-Gel technique for textile finishing antistatic and repellent surfaces

Torsten Textor1, Boris Mahltig2

1 Deutsches Textilforschungszentrum Nord-West e.V.

Krefeld, (DTNW)

2 Gesellschaft zur Förderung von Medizin-, Bio- und Umwelttechnologien e.V., Dresden, (GMBU)

DT NW

2 DT NW

Problem

during winter or generally in dry environments a electro-static charging occurs, e.g., in case of -  Walking over a carpet -  Getting into/out off a car -  Taking off a pullover -  Combing of hair …

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Effect

• Attraction/repulsion of light particles • Increased soiling • Electric shock (sometimes painful) • Spark formation • Ignition of flammable vapor, gases, powders • Unexpected operation of airbags • Explosion at gas stations (unfrequently, but it happens!)

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Parameters influencing the charging developing if two surfaces are separated •  materials that are in contact •  area of contact •  velocity of separation •  purity of the surfaces •  amount of humidity at the surface

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Surface resistance of textile fibers Amount of humidity stored

Viscose 107 10-12 Cotton 108 8-10 Polyamide 1012 4 PAN 1014 1,5 PET 1014 0,3-0,4 PVC 1014 0,2 PP 1015 <0,1

[Ω]+ [wt.-%]

•  65% rel. atmospheric moisture, 21°C • + nach DIN 54345

Wirkerei- und Strickerei-Technik 41 (1991) 7

antistatic finishing à hydrophilic finishing

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Rating of the quality of an antistatic finishing

< 5*109 Ω excellent 5*109 – 5*1010 Ω good 5*1010 - 2,5*1011 Ω average > 2,5*1011 Ω bad

7

Aims

Development of coatings based on i/o-hybrid polymers or nanosols, lowering the surface resistance below 5*109 Ohm Maintaining or achieving a good repellence of the antistatic textile

DT NW

low surface resistance + high repellence

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(RO)4Si

(SiO2)n

(SiO2)m

(SiO2)m

AD

DIT

IVE Precursors

Nanosol

Lyogel

Xerogel

Preparation and Modification of inorganic nanosols

Hydrolysis

application, e.g., textile

Drying, curing

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ADDITIVE = hydrophobic/oleophobic alcoxy silanes

Repellence = hydrophobic/oleophobic surfaces

10

Contact angle of a hydrophobic hybrid polymer (applied to a PET-Film)

DT NW CF3 (CF2)5 (CH2)2 Si

OC2H5

OC2H5

OC2H5

fluoro-modified alkoxy silane

Increasing amount of the

fluorine compound

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12 DT NW

e.g., quarternary ammonia compounds, ionic silanes or amines

improved antistatic effect à hydrophilic surface

ADDITIVE = hydrophilic alcoxy silanes

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Combining two opposed properties?! Hydrophobic and hydrophilic?!

hydrophobic

hydrophilic

humidity

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SiO2 C1 C4 Phenyl C8 C12 C16 Referenz0

1

2

3

4

5

6

7

DuP

ont N

ote

SiO2-Sol Behandlung von Polyester Reihe M639

Si

OC2H5

OC2H5

H5C2OCH3

hydrophobic modification of a polyester farbic employing different alkyl silanes

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SiO2 C1 C4 Phenyl C8 C12 C16 Referenz

1E11

1E12

1E13

Obe

rfläc

henw

ider

stan

d [O

hm]

SiO2-Sol Behandlung von Polyester Reihe M639

Si

OC2H5

OC2H5

H5C2OCH3

… effect for the surface conductivity?!

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0 2 4 6 8 10 12 14 16 18 20

1E7

1E8

1E9

1E10

Obe

rfläc

henw

ider

stan

d [O

hm]

Konzentration Aminosilan [vol-%]

APS AAPM TRIAMO

Reihe M699 , Sol aus TEOS und MTES mitsteigender Menge an Aminosilanenauf Mischgewebe Polyester/Baumwolle

… increasing the amount of amino silane standard-sol + hydrophobic additive + amino silane

Si

OC2H5

OC2H5

H5C2ONH2

Si

OCH3

OCH3

OCH3

NH NH2

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0 2 4 6 8 10 12 14 16

1E7

1E8

1E9

1E10

1E11

1E12

1E13 PES-fabric; 9,8% APS CO/PES-fabric; 9,8% APS PES-fabric; 17,8% APS CO/PES-fabric; 17,8% APS

surfa

ce re

sist

ance

[Ohm

]

chain length [C-Atoms]

standard-sol + hydrophobic additive + amino silane varying the hydrophobic additive …

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10 20 30 40 50

1E7

1E8

1E9

1E10

1E11

1E12

1E13

TEOS/APS-Sol varying Hexadecylsilane concentration

PES; 9,8% APS CO/PES; 9,8% APS PES; 17,8% APS CO/PES; 17,8% APS

surfa

ce re

sist

ance

[Ohm

]

share of C16 compared to TEOS [vol-%]

… increasing the amount of the hydrophobic compound

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0 2 4 6 8 10 12 14 160

5

10

15

20

25

30

35

40

45

50

55

60

TEG

EW

A d

rop

pene

tratio

n tim

e [m

in]

chain length [C-Atoms]

CO/PES-fabric; 9,8% APS CO/PES-fabric; 17,8% APS

TEGEWA drop penetration time

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Water-repellence, DuPont Grading

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Modification with fluorinated Additives

M758A M758B M758C M758D M758E0

1

2

3

4

5

6

7

8

DuP

ont G

radi

ng

fluor modified sols

CO/PET PET

Oil repellence (AATCC 1970): also up to 8

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M758A M758B M758C M758D M758E

1E7

1E8

1E9

1E10su

rface

resi

stan

ce [O

hm]

fluor modified sols

CO/PET PET

Modification with fluorinated Additives

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0 2 4 6 8 10 12 14 16 18

1E7

1E8

1E9

1E10

1E11

1E12

9,8% share of AAPM 17,8% share of AAPM 9,8%; +55000 scrubbing cycles 17,8%; +55000 scrubbing cycles

Sample M715, Polyester

surfa

ce re

sist

ance

[Ohm

]

chainlength [C-atoms]

Scrub-resistance

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Laundry tests

0 2 4 6 8 10 12 14 16 18 20

1E7

1E8

1E9

1E10

1E11

Sol M759 - TRIAMO/MTES-Sols

surf

ace

resi

stan

ce [O

hm]

concentration TRIAMO [vol-%]

CO/PES PES CO/PES - after laundry PES - after laundry

5:1 3:1 1:11E7

1E9

1E11

surf

ace

re

sist

an

ce [O

hm

]ratio TEOS:GPTMS

Polyester PET/CO Polyester after laundring PET/CO after laundring

17,8% AAPM + OctyltriethoxysilanLini-Tester bei 60°C

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APS Triamo

Theoretical XPS rel. shortfall/excess theoretical XPS rel. shortfall/excess

O 26wt.% 25wt.% 22wt.% 17wt.%

N 11wt.% 7wt.% -32% 18wt.% 10wt.% -44% C 35wt.% 46wt.% +30% 49wt.% 55wt.% +14%

Si 28wt.% 22wt.% 11wt.% 18wt.%

XPS-measurements

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0 50 100 150 20020

40

60

80

100

120

90

92

94

96

98

100

102

tem

pera

ture

[°C

]

time [minutes]

sample w

eight [%]

Change of weight during heating

27 DT NW Mahltig et al., Journal of Materials Chemistry 2005, DOI: 10.1039/b505177k

super-paramagnetic magnetic coatings

photocatalytic activity

Antistatic+repellence improved stab-resistance

Sol-gel-coating improving the weather

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Acknowledgements

We thank the DECHEMA Gesellschaft für Chemische Technik und Biotechnologie e.V.

for financial support of the project AiF-Nr. 15299BG, which is part of the programm to support the „Industriellen Gemeinschaftsforschung (IGF)� with financial

resources of the Bundesministeriums für Wirtschaft und Technologie (BMWi) which was carried out by the Arbeitsgemeinschaft industrieller

Forschungsvereinigungen e.V. (AiF)

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Thank you for your attention!

textor@dtnw.de +49 2151 843-159

mahltig@gmbu.de +49 03512695340