Leather and soiling: an exploration of current anti-soiling technologies Dr. Dietrich Tegtmeyer Vice President Product Development and Application Business

Leather and soiling: an exploration of current anti-soiling technologies

Dr. Dietrich TegtmeyerVice President

Product Development and Application

Business Unit Leather

SLTC; September 26th, 20092

Antisoiling Systems

For A Change In Leather

- leather is a classic yet highly fashionable article

- leather undergoes a continuous development with regards to its longevity

- due to the consumer’s requirements the color shades of leather goods have changed over the past

- color shades have become lighter


Antisoiling Systems

The Challenge

- bright colors are by nature more sensitive to soiling and staining

- enhanced anti-soiling / anti-staining and cleaning behavior are of need

- performance and esthetics of leather must be maintained

- leather must remain leather with all its desirable properties


Antisoiling Systems

• Basics Definitions and Theory

• Differentiation of Performance Characteristics

• Testing of Antisoiling Characteristics

• Chemistry of the New Antisoiling Technology

• Test Results

• Summary / Conclusions

Today’s Agenda


Antisoiling Systems

Nano foam

Nano particles

1 Nanometer = 0,0000000001 meter

= 1 * 10 EXP-9 meter

1 nm : 1 mm

football : earth

Picture: GNU Free Documentation License

Nano colloids

Nano tubes

Basics – Definition of Nano Technology


Antisoiling Systems

bis 160 °

Pictures: GNU Free Documentation License

Basics – Definition of Lotus Effekt


Antisoiling Systems

Basics – Lotus Effect means a self cleaning capability of the surface



Antisoiling Systems

Aesthetical properties

• Touch• Feel • Smell

Many requirements for a finishing chemistry

Fastenessproperties

• Hydrolysis• Lightfastness• Color Strength

Physicalproperties

• Abrasion• Adhesion• Flex• Antisqueek

Processproperties

• Recoatability• Flow out• Drying• Staking


Antisoiling Systems

print

binder elasticitylow high

flex

General problem: if you optimize one of the properties, you are sacrifying others

A lot of criteria are behaving complementary

Challenge for chemistry: we have to look for the best compromise or

for the application: we have to formulate around weaknesses


Antisoiling Systems

Aesthetical properties

ANTISOILING • Touch• Feel • Smell

Anti-soiling is one additional category, also complementary to important other requirements

?

Fastenessproperties

• Hydrolysis• Lightfastness• Color Strength

Physicalproperties

• Abrasion• Adhesion• Flex• Antisqueak

Processproperties

• Recoatability• Flow out• Drying• Staking

Anti-soiling

Recoatability


Antisoiling Systems

• matting system • binder chemistry

• degree of X-linking • additives e.g. thickener

• embossing • drying conditions

Anti-soiling is a very complex requirementand influenced mainly by surface parameters of the leather

Surface

Morphologyphysics

Substancechemistry

Marcro Scale> 1 µm

Micro Scale10 – 1000 nm

Hydrophobicity Oleophobicity


Antisoiling Systems

Macro Scale: Surface Porosity of a conventional top coat

A high amount of holes visible on the surface in a range of 5 µm

5.5 µm


Antisoiling Systems

A small amount of holes visible on the surface in a range of 5 µm

Macro Scale: Surface Porosity of a conventional top coatwith good anti-soiling perforance


Antisoiling Systems

Surface Porosity of a top coat of the new PTFE Copolymer

Basically zero holes visible on the surface in a range of 5 µm

Less penetration of soil can be easier cleaned away, but after soiling

it also appears more dirty on the surface!


Antisoiling Systems

e.g. little pins on the surfacein nano rangecould lead to a self cleaning effect

Micro Scale: Surface structure of a lotus leave



Antisoiling Systems

• matting system • binder chemistry

• degree of X-linking • additives e.g. thickener

• embossing • drying conditions

Surface

Morphologyphysics

Substancechemistry

Marcro Scale> 1 µm

Micro Scale10 – 1000 nm

Hydrophobicity Oleophobicity

Anti-soiling is a very complex requirementand influenced mainly by surface parameters of the leather


Antisoiling Systems

A good antisoiling performance is not the result of one single additive -

but one wrong single additive could have a very negative impact

• for some tests acrylic chemistry is better suited than PU chemistry

• low concentration of emulsifier

• only special silicons are required

• special matting agents, which generate a small surface and have a low porosity

• high X-linking, not only for the permanence, even for the antisoiling effect

• special additives can improve the anti-soiling performance

The right formulation is one of the important basics


Antisoiling Systems

Adhesion of dirt is determined by the surface chemistry

Hydrophobicity

Oleophobicity

Silicon Area

PTFE Area

Parafin Area

the best anti-soiling characteristicshould be in the right upper square

Additives and binder chemistrydo influence the surface properties


Antisoiling Systems





• Test Results


Today’s Agenda


Antisoiling Systems

Requirements

Anti-Staining:

- mainly required by the furniture industry

Anti-Soiling:

- mainly required by the automotive industry

Cleanabilty:

- required by both furniture and automotive industry


Antisoiling Systems

1. Dirt ≠ Dirt

The contamination of leather must be differentiated by different pollutants:

Staining:

- accidental and occasional contamination of leather

- wine, coffee, lipstick, ball pen etc.

before soiling after soilingSoiling

Soiling:

- constant exposure of leather to dirt throughout daily use

- ambient dust, dyestuffs from garment, carbons, oils etc.

Staining


Antisoiling Systems

What is soiling / cleanability about ? We differentiate between …

Cleanability:

- The behavior of leather surfaces to cleaning after a contamination has occured

- Can the contaminant(s) be removed ?

- How easily can the contaminant(s) be removed ?

- How much residue remains on the leather surface ?

Durability of anti-soiling finishes:

- Gives an indication about the “longevity” of anti-soiling finishes

- How many times can a leather be soiled and cleaned

maintaining it anti-soiling / cleanability performance ?

2. Cleaning ≠ Cleaning


Antisoiling Systems

3. Testing ≠ Testing

Different kinds of “dirt” are applied and cleaned by different test methods.

Staining:

- is tested by applying the contaminants onto the leather directly

- subsequently the dirt is wiped off with common household cleaners

- cleaning efficacy is evaluated and rated

after staining after cleaning


Antisoiling Systems

Testing ≠ Testing

Soiling:

- standardized fabrics, contaminated with different pollutants are rubbed over the leather by means of the Martindale abrasion tester

- after 2.000 cycles the degree of color change on the leather is measured

- subsequently the dirt is wiped off by means of common leather cleaners and the color change is measured again

Conventional

Finish

after soiling

after cleaning

Attentio

n: diffe

rent testin

g procedures do result in

different d

ata !


Antisoiling Systems

How is soiling tested ?

Anti-Soiling 1 ( VDA Test ):

- Contaminants are applied on the leather by

standardized soiling clothes*.

*EMPA 104:

polyester/cotton, soiled with carbon black / olive oil

*EMPA 128:

cotton jeans with indigo/sulfur black, soiled with carbon black / olive oil

EMPA 104

EMPA 128

without X-Shield top with X-Shield top

before after

cleaning

before after

cleaning

EMPA 104

with X-Shield topwithout X-Shield top

before after

cleaning

before after

cleaning

EMPA 128

Different contamination


Antisoiling Systems


Anti-Soiling 1 ( VDA Test ):

- Testing is done by Martindale abrasion tester:

- 1.000 cycles, weight 12Kpa,

large Lissajous figure with:

- Pilling holder* ( Ø 140 mm ) or

- Abrasion holder* (Ø 38 mm )

( *depending on specification )

- Degree of soiling before cleaning:

Requirement: ≥ 3 ( grey scale )

- Degree of soiling after cleaning:

Requirement: ≥ 4-5 ( grey scale )

Abrasion holder, Ø 38 mm


before after

cleaning

before after

cleaning

Pilling holder, Ø 140 mm


before after

cleaning

before after

cleaning

Different holders/conditions


Antisoiling Systems


Anti-Soiling 2 ( Dye Ingress Test ):

- Contaminants are applied on the leather by

a standardized “soiling cloth*”.

*standard JLR denim fabric with indigo dye,

soaked in alkaline sweat solution ( BS1006 E04 )

soiling cloth

cleaning cloth

Different testing fabrics/conditions


Antisoiling Systems


Anti-Soiling 2 ( Dye Ingress Test ):

- Testing is done by Martindale abrasion tester:

- 1.000 cycles, weight 12Kpa, large Lissajous figure

- Abrasion holder

( small specimen holder, 38 mm )

- Degree of soiling before cleaning:

Requirement: ≥ 4 ( grey scale )

- Degree of soiling after cleaning ( 1.000 cycles as

described above; cleaning cloth soaked in

cleaner; e.g. “Leather Master” car interior

leather cleaner:

Requirement: ≥ 4-5 ( grey scale )

Standard PU Top

after cleaning

LXS Acrylic Top

after cleaning

Different testing fabrics/conditions


Antisoiling Systems





• Test Results


Today’s Agenda


Antisoiling Systems

Individualized Systems

- a wide variety of potential contaminants along with an even bigger number of different leather properties require different antisoiling systems

- the goal is to achieve the best possible spectrum of efficacy

- TFE ( tetrafluoroethene ) based products have proven to be the best suitable substances for those applications


Antisoiling Systems

Polytetrafluorethene ( PTFE ), The Solution

PTFE

- provides hydrophobic and oleophobic effects at the same time

- thermo stable from -200°C to +260° C

- chemically inert and resistant against UV radiation

- provides low friction and excellent release properties

- has extremely low surface energy


Antisoiling Systems

TFE Containing Copolymers, Different Options

1. Comb Polymer

Advantages:

- excellent dirt repellency

- excellent initial cleanability

TFE containing side chains

TFE protection top

2. Linear Polymer

Advantages:

- excellent dirt repellency

- excellent cleanability and durability

TFE groups are built into the monomer

TFE copolymer binder

TFE groups can be incorporated in two different ways


Antisoiling Systems

Comb Polymer Structure

AQUADERM® X-Shield L facts:

- used as an additive in special top coats

- cross-linking of pure product not possible ( limited durability )

- outstanding dirt repellency

- outstanding initial cleanability

AQUADERM® X-Shield L

Important note:

- PFOS (perfluoroctylsulfonic acid)

- PFOA (perfluoroctanoic acid)

Analysis of leather finished with AQUADERM® X-Shield L have proven that neither PFOS nor PFOA are detectable.


Antisoiling Systems


Antisoiling Systems

With And Without....

Conventional Finish

AQUADERM® X-Shield LFinish

after soiling after soilingafter cleaning after cleaning


Antisoiling Systems

Linear Polymer Structure

- TFE copolymers + different functional groups offer a versatile application field to the leather industry

Protection coats which consist of AQUADERM® X-Shield G / M2

- can be pigmented- can be cross-linked with isocyanate- are film forming- allow to adjust different gloss levels- can be fine tuned by the addition of

feel agents- provide superior and long lasting

abrasion resistance

AQUADERM® X-Shield G / M2


Antisoiling Systems

Linear Polymer Structure

R1

|CH - CH a CF2 - CF2 c CH2 - CH d CH2 - CH e

|CH - CH b

|X Y ZCOO-

HN+R3

||

R2

|

COO-

HN+R3

|

film formation /transparency

antisoiling /cleanability

cross-linking /adhesion

pigmentdispersibility

dispersionstability

- functional groups: approx. 50 % in total

- built-in PTFE segments: approx. 50 % in total


Antisoiling Systems

Different To Conventional Fluorine Systems

- the X-Shield system is based on a new concept providing permanent protection

- the integrated PTFE segments in a polymer backbone are stable against hydrolytic attack ( bound by stable C-C bonds )

- additional segments provide film formation and reactivity

- long lasting protection along with environmental soundness

R

Leather Surface

PTFE segment

non fluorinated segment

TFE -copolymer

R NCO

OCN

OCN

cross-linking reaction

+

R

R

RR


Antisoiling Systems

Cleanability performance as a function of cycles

Only one cycle is currently part of automotive specs!Long term cleanability is a new challenge.

0

1

2

3

4

5

before cleaningafter cleaning

complementaryAntisoiling system conventional

PTFE binder

1. 2. 3. 4. cleaning cycle

poor

excellent


Antisoiling Systems

Consistancy of Cleanability performance is an issue

Only one cycle is currently part of automotive specs!Long term cleanability is a new challenge.

1. 2. 3. 4. cleaning cycle

0

1

2

3

4

5


Antisoiling system conventional

PTFE binder

poor

excellent


Antisoiling Systems

1. 2. cleaning cycle

Cleanability performance suffers after pre-treatment

A tough pre-treatment influences the anti-soiling performance.

0

1

2

3

4

5

before cleaningafter cleaningPre-treatment

3.000 cyclesMartindale

w/clean cloth

48 h Hydrolysis Antisoiling system

Typ A

Typ B

poor

excellent


Antisoiling Systems

Special protection top doesn‘t show soiling at allin all EMPA tests. It is however not a long lasting effect

1 cleaning cycle

0

1

2

3

4

5


Comparison of soiling performance of X-Shield G and L

Anti-soiling system conventional

PTFE binder

PTFE protection top

poor

excellent


Antisoiling Systems

final antisoiling performance depends on article characteristics

The Finishing System is playing an important role

Gloss level

Recoatability

Anti squeek

Flex Performance

Impact on Antisoilingperfomance

dull…….medium……….glossy

high…….…..medium……...poor

excellent…… regular …....… poor

excellent..…..good …...… medium

decreasing improving

Adjustments of

certain parameters / physical properties

have an impact

on antisoiling performance


Antisoiling Systems





• Test Results


Today’s Agenda


Antisoiling Systems

Two main conclusions

1.) There is no universal system which fullfills overall best performance

in terms of

• Antistaining

• Antisoiling

• Cleanability

You have to chose the best system for you specific application requirements

2.) You have to minimize the negative impacts of other properties such as

dulling, anti squeek, etc.


Antisoiling Systems

Best systems for Antisoiling

In dependence of the leather goods manufacturers’ requirements the X-Shield system allows the individual customization of all kinds of leather articles.

AQUADERM® X-Shield L

- for optimized anti-soiling and initial cleanability performance in EMPA test

HYDRHOLAC AD1 and CL1

- for optimized anti-soiling in Dye Ingress test

X-Shield ProtectedConventional Finish


Antisoiling Systems

AQUADERM® X-Shield G,( gloss component )

in combination with

AQUADERM® X-Shield M2,( matting component )

- for efficient and long lasting anti-staining protection and long term cleanability

Conventional Finish

before cleaning after cleaning

X-Shield Protected

before cleaning after cleaning

Best systems for Antistaining and Cleanability


Antisoiling Systems

Individual systems for individual specifications

Product Staining Anti-Soiling VDA

Anti-Soiling Dye Ingress

AQUADERM X-Shield G x x

AQUADERM X-Shield M 2 EXP 2002 x

AQUADERM X-Shield L EXP 2001 x

HYDRHOLAC AD-1 x x

AQUADERM Matt HPM-N x

HYDRHOLAC CL-1 x x

HYDRHOLAC AQS x

AQUADERM Additive GF x x x

AQUADERM Additive SF x x x

ROSILK 2229 FM x x

Different systems for different requirements


Antisoiling Systems

Summary

The AQUADERM® X-Shield range:

- functional products providing additional performance

and value to leather industry

- unique chemistry for leather

- strong effect

- significant extra value of the leather article

A special labeling is offered to the industry


Antisoiling Systems

Thank you for your attention

Documents

Leather and soiling: an exploration of current anti-soiling technologies Dr. Dietrich Tegtmeyer Vice President Product Development and Application Business