Jörg Wollschläger

Additive groups

Applications

Rheology modifiers

Defoamers

Dispersants

Wetting and leveling agents

Conclusion

2

Filmforming agent (polymer/ resin)

Pigments and Extenders/Fillers

Solvents

(organic and /or water)

Additives

non volatile

volatile

From BASF-handbook of coatings technology3

- Defoamer

- Dispersant

- Wetting agent

- Leveling agent

- Rheology additive

- Catalyst

e.g. dryer for alkyds, DBTL for 2K PU

- Film formation aids

different types of solvents

- Corrosion inhibitororganic and inorganic chemicals

- UV absorberHALS

- Anti-oxidante.g. anti-skinning agents for drying alkyds

- Matting agent

waxes, silica

- Adhesion improver

silanes, resins

- Anti-foulingorgano-tin compounds

- Preservativebiocide, fungicide

This is not a complete listing of additives4

Substrate

Liquidphase

Pigment/ Dispersant

Pigment

Wetting/ leveling additive

Defoamer

Emulsified

Binder-emulsion

Micelle

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Binder types:

Substrates:

Concrete, Wood, Metal, Bricks, Gypsum, Lime, Wallpaper , Glass, Plastics, Paper

Application devices:

Paint roller, brush, airless- spray gun, Spray booth, trowel, Dip-Coating, Flow-coating, Printing machines

-Acrylates, Styrene Acrylates-Polyurethans, Epoxies-Vinyl Acetate Copolymers-Water Glass-Silicone Resins

Pigments :

-TiO2

- Iron Oxides- Fillers- Carbon Black- Organic Pigments- Functional Pigments

Types of Coatings:

Architectural, Decorative, Industrial, Printing Inks, Dry mixes, Adhesives

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Paint roller

Brush

Roller for enamels

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Airless spray gunwith air directed spray

Air assisted flow cup spray gun

HVLP pressurised cup spray gun

Spray cabin

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9

Rheology modifiers

Defoamers

Dispersants

Wetting and leveling agents

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Pseudoplastic, thixotropic (shear thinning)e.g. ketchup

vis

cosi

ty

shear rate

Dilatant(shear thickening)e.g. starch dispersion

Newtonian(ideal flow behaviour)e.g. water, oil

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s-1

1 10 100 100

0 1000

0

transport, storage, sedimentation

levelling, sagging

stirring, flow, general

appearance roller application,

brushing, spraying

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Sagging Spatter Color strength

Roller/brush marks Levelling Hiding power

Poor !

Poor !

Poor !

Poor !

Poor !

Poor !

Influenced by resulting rheology Influenced by chemical structure13

Organic thickeners for water based systems

Non Associative Thickeners

Cellulose derivatives CE

Alkali swellable emulsions ASE

Associative Thickeners

Hydrophobically modified cellulose ethers HMHEC

Hydrophobically modified alkali swellable emulsions HASE

Hydrophobically modified polyurethanes HEUR

Inorganic thickeners (organo modified) for solvent based and water based paints

Bentonite

Silica

Organo clays

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15

equalactive substance(1.04 %)

1

10

100

1.000

10.000

mPa·s

0,1 1 10 100 1.000 10.0001/s

shear rate .

without thickener

2,6% TAFIGEL® PUR 40

4,16% TAFIGEL® PUR 85

5,2% TAFIGEL® PUR 54

5,2% TAFIGEL® PUR 82

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s-1 1 10 100 1000 10000

transport, storage, sedimentation

leveling, sagging

stirring, flow, general appearance

roller application, brushing, spraying

Flow cup(4mm)

Brookfield

Rotation/Oscillation rheometer

ICI cone/plate

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Sagging resistance higher than 300 µm

Sagging resistance 210 µm

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Indication for changes

during storage

General appearance

Quality control

Dilution adjustment

Krebs-Stormer BrookfieldFlow cup(DIN; FORD; ISO)

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Predict behavior and properties of coatings during production, storage, transport and application

Speed up development, additive choice and explanation of unexpected behavior of materials

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Rheology modifiers

Defoamers

Dispersants

Wetting and leveling agents

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Foam is a (stable) dispersion of a gas phase in a liquid system

Surfactants are necessary in order to stabilise a gas bubble (hydrophobic particle) in an aqueous environment

Defoamers are necessary in order to destroy the foam or

to prevent foam formation

What is foam?

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23

pure water surfactant containing water

surfactant molecules

hydrophobic particle

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Production • Production vessels are not optimally filled

• Dispersing process is inefficient

Application • Formation of pinholes

• Reduced protection

• Reduction of gloss and transparency

• Negative effect on leveling

Aspect • Optical aspect negative

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Mechanical processes during production grinding, stirring, pumping, filling

Emulsion polymers / binders with emulsifiers problem mainly in waterbased systems

Presence of surface active compounds wetting and dispersing agents, thickeners, leveling agents, …

Presence of other paint ingredients solvents, pigments & fillers with included air, ...

Application roller, curtain, flow, circulation, printing, ...

Porous substrates

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Carriers Oils, water, solvents, modified Polyether siloxanes, Oleo-ABCs

75 – 90%

Hydrophobic

ingredients

Waxes, hydrophobic silica, metal soaps, paraffin, amides, polyalkylene glycols, polyurethanes

5 – 10%

Emulsifiers Surfactants 0 – 5%

Others Biocides, thickeners, protective colloids

0 – 20%

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Carriers Transport of active ingredients to the surface, spread on the surface and prevent formation of a surfactant‘s layer

Hydrophobic ingredients

Absorb surfactant molecules and enter into lamella double layer

Emulsifiers Adjust emulsify ability (compatibility) of the defoamers in the system

Support spreading of the defoamers at the surface

Others Adjust of viscosity, prevent separation, fouling

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1.0% defoamerRed Devil-Test

% airCompatibility

Rollwet / dry

Leveling 100 µm (wet) on glass

Gloss

Overall CR OP 20°

Blank 27,3% homogeneous 2 / 2 10 n n 74.8

Competitor 10,6% homogeneous 9 / 10 9 n-f n 72.8

AGITAN® 155 6,5% homogeneous 9 / 10 10 n n 75.8

AGITAN® 156 11,9% homogeneous 9 / 10 10 n n 74.7

AGITAN® 158 4,1% homogeneous 10 / 10 10 n n 72.1

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30

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Rheology modifiers

Defoamers

Dispersants

Wetting and leveling agents

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Inorganic pigments:• Titanium dioxide• Fillers (CaCo3,

talcum)• Iron Oxides, earth pigment

• Carbon black• Bismuth vanadate

Colorants

Dyestuff: soluble in the application media

Pigments:insoluble particles

Organic pigments• Phthalocyanine• AZO Pigment • Perylen• Chinacridone

Functionalpigments(e.g. anti-corrosive,conductive)

Effect pigments(e.g. metallics, pearlescent)

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Particle size

(µm) Surface (m²/g)

Inorganic Pigments and Fillers 0,3 – 5,0 5 – 20

- Calcium Carbonate 3 – 8

- Titanium Dioxide 0,3 – 1,0 8 – 15

- Standard Iron Oxide Red 0,1 – 1,0

Organic Pigments 0,05 – 1,0 50 – 100

- Phthalo Cyanine Blue 0,06 – 0,1 30 – 120

Carbon Blacks 0,05 – 0,5 30 – 1600

- furnace black 0,05 – 0,1 15 – 50

- gas black 0,005 – 0,03 100 - 1000

Transparent inorganic pigments

- transparent Iron Oxide Red 0,001 – 0,01 500 - 5000

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pigment in powder form

wetted agglomerate dispersed pigment

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Wetting of pigments Replacement of air and humidity

Support of grinding Short dispersing time, optimum degree of grinding

Reduction of grind viscosity High pigment loading, flowability

Stabilization of the dispersion Color strength, gloss, color shade stability

Compatibility with resins No flocculation (Rub-Out), broad application

No influence on coatings Water resistance, film hardness, scrub resistance

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% Dispersant

10 min. disperse with a Red Devil Shaker

Red Devil Shaker

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Competitor 1 Competitor 2 Competitor 3 Competitor 4Anionic

CopolymerEDAPLAN®

492

Color Black FW 285 15.00 %

% Dispersant on Pigment 112.5% 112.5% 112.5% 50% 128.6% 128.6%

% Active Content onPigment

45%

Appearance of Paste after 1 Week at 40°C

without sediment

low viscous

without sediment

low viscous

without sediment

low viscous

without sedimentmedium viscous

without sediment

low viscous

without sediment

low viscous

Clear Coating

Color Strength 433.25 454.80 417.53 259.16 369.42 467.14

Gloss 20° 89.9 89.9 89.4 64.9 87.3 89.4

Haze 49.8 53.7 52.5 239 58.6 53.3

Flocculation/Specks 0 1 0 3 0 0

White PU Acrylic Coating

Color Strength 3.58 3.47 3.53 3.57 3.62 3.96

Rub-Out (E) 1.37 1.60 1.40 1.08 1.25 0.46

Gloss 20° 55.6 55.4 55.4 54.0 55.6 55.0

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Colorimetric datas: Color strength, color shade (CIELAB), metamerism

Viscosity, flowing properties: Viscosimeter (Brookfield/Krebs-Stormer), Rheometer cone-plate, flow cup

Particle size: Grindometer, particle size measurement

Incorporation, compatibility: White base, clear system

Application: Printing, spraying, roller coating

Drying behavior, exactness of dosing (tinting machines)

Rub-out

Sedimentation/ Antisettling

Storage stability

Stability of color shade

Gloss

Transparency / hiding power

pH value

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0

20

40

60

80

100

5 15 25 45

gloss

haze

particle size (µm)

Dispersing time (min)40

Rheology modifiers

Defoamers

Dispersants

Wetting and leveling agents

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Pinholes

Fish Eyes

Orange Peel

Brush/Roller Marks

Cracking

Sagging

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Volume reduction during drying

Solvent evaporation

Film weight / Film thickness

Rheology / Viscosity

Application Method

Drying time / Open time

Poor defoaming

Contaminants

Surface tension of the liquid coating is too high

Variation of surface tension / unequal surface tension

in the wet film

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...that can not be solved with wetting agents:

...that can be solved with wetting agents:

Cracking Sagging Roller / Brush Marks Pinholes …..

Craters Fish Eyes Orange Peel Compatibility …..

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The lower the contact angle q, the better the wetting of the substrate

The contact angle is influenced by the surface tension (s) of the liquidand the surface energy (s) of the substrate

A liquid spreads on a substrate, if the surface tension of the liquid is lower compared to the surface energy of the substrate

S liquid < S substrate

What is the important criteria for good wetting:

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Liquids; Solvents

surface tension S

[mN/m] Substrate

surface energy S

[mN/m]

xylene 32 glass 73

butyl glycol 27 PVC 39 - 42

butyl acetate 25 phosphated steel 43 - 46

water 72 aluminium ~ 40

water + 0,5%METOLAT® 365

26 polystyrene 36 - 42

polyester 43

Wetting: S coating < S substrate

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or good hydrophobing

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Improvement of color acceptance in a silicone emulsion paintPigment concentrate based on PY 42 (Iron oxide yellow)

without additive 1% METOLAT® 367added to the paint

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waterbased UV inkjet ink+ additive

compatibility after 24 h

leveling 12 µm on black white charts

surface tension[mN/m]

recirculation test % foam after

overall cr op 1 min 5 min 10 min1 min

collapse

without additive homogeneous 8 f n 39.93 81.3 81.3 81.3 81.3

reference sample homogeneous 8 s n 26.58 200 188.8 188.3 188.8

0.5% current LA homogeneous 9 f n 22.62 200 206.3 208.8 206.3

0.5% current LA0.05% current defoamer homogeneous 7 s n 26.74 205.8 203.8 205.6 205.5

0.5% EDAPLAN® LA 403 homogeneous 10 n n 37.79 93.8 93.8 100 81.3

0.5% METOLAT® 362 streaks 4 m n

0.5% METOLAT® 366 streaks 2 m n

0.5% EDAPLAN® LA 452 homogeneous 9 f n 25.65 87.5 93.8 95.6 88.8

0.05% AGITAN® E 256+0.5% EDAPLAN® LA 452 streaks 4 m n 27.29 -- -- -- --

0.05% AGITAN® 158+0.5% EDAPLAN® LA 452 streaks 2 m n 26.73 -- -- -- --

0.05% AGITAN® 155+0.5% EDAPLAN® LA 452 homogeneous 8 f n 25.05 31.3 37.5 43.8 25

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Static interfacial tension

Dynamic interfacial

tension

Substrate wetting

Contact angle50

REACH

CLP – label-free

FDA chapters, like 176.210, 175.300 …

Swiss Ordinance

Decopaint guideline

VOC reduction

Biocide guidelines

Eco label like EU-flower, Blue Angel, Nordic Swan

Low emission wall paints

BfR chapters

Renewable – biobased – „ green chemistry “

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Interaction of different additive groups in the formulation

Synergistic effects – potentiating or no/negative effect

Chemical composition and reactions

Application parameters and drying conditions

Regulatory requirements

Price/ Performance

Finding the right balance !!!

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Please feel free toask questions

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