How to get the Best From Your Carbon BlackPNW Coatings SocietyOctober 2014

Agenda

2

• Review of Carbon Black Fundamentals• Dispersion Process and Optimization

• Process• Wetting• Dispersion• Stabilization

• Correct Carbon Black Product• Dispersant types

• Examples• Summary

Review of Carbon Black Fundamentals

• Fineness• Particle Size Distribution

• Structure• Aggregate Size/Shape Distribution

• Porosity • Pore Size Distribution

• Surface Activity• Surface Functionality Distribution

4

Four Fundamental Properties of Carbon Black

Properties of Carbon Black - Primary Particle Size

5

• Measured directly by Electron Microscope or indirectly by tint test, ISA, NSA• A wide distribution of particle sizes within a product, but similar particle

size within an aggregate • Birla Carbon make blacks with mean particle sizes from 8 nm to 100 nm

Raven 410100 nm

Conductex 7055 Ultra42 nm

Raven 125521 nm

Raven 5000 Ultra II8nm

Surface area and its influence

6

• Smaller particle diameter generally leads to high surface area • Surface area typically measured by nitrogen absorption (ASTM

D6556) or iodine titration (ASTM D1510)• Birla Carbon’s carbon blacks have surface areas ranging from 25-

580+ m2/g

• High surface area is the single biggest predictor ofcolor performance (masstone and tint)

• Higher surface area increase viscosity and conductivity and UV protection

• High surface area lower dispersibility

Carbon Blacks

7

Structure – Oil Absorption Number (ASTM D2414)

8

• Oil Absorption Number, primarily influenced by aggregate size/shape, may be influenced by porosity

• The amount of oil to reach a peak torque, results given as cubic centimetres of oil per 100 g carbon black

Effect of Structure on Performance

9

Higher structure (OAN) leads to

• Slightly lower blackness and tint strength

• Better dispersibility

• Higher viscosity and vehicle demand

• Higher electrical and thermal conductivity

Porosity and its Influence

10

• Porosity is caused by oxidation in the reactor and is controlled by residence time

• Indicated by a difference between Nitrogen Surface Area (NSA) & Statistical Thickness Surface Area (STSA)

• High porosity gives an increase in• Conductivity• Viscosity• Moisture pick up

• High porosity• Enables a low loading in conductive applications• Decreases gloss

Surface Activity and its Influence

11

• Property describing the interaction of a carbon black surface with its surroundings

• Furnace carbon blacks can be chemically surface treated after production to mimic channel blacks

• Increase of surface activity by an increased number of acid groups leads to improved dispersion

• Improves wetting of the carbon black by most vehicle systems

• Reduces viscosity in liquid systems

• Reduces conductivity

Carbon Blackas produced

Post treatment adds oxygen groups to the surface

Oxidation

950 OCNo Oxygen

Measurement of Surface Activity

12

• Volatile (Mass loss at 950 °C)• Usually indicative of oxygen function groups, sometimes influenced by

moisture, sulfur and toluene extract

• pH (ASTM D1512)• Generally assumed to indicate surface acidity by oxygen functional

groups, often strongly influenced by sulfur levels

• Oxygen Content• Direct measure of bulk oxygen

• XPS Analysis• Measure of surface composition by atomic type, and some qualitative

information on oxygen functionalities

Oxygen Functionality – Volatile

13

Carboxyl Phenol Aldehyde Lactone Quinone Anhydride Ether

Increasing Acidity

Dispersion Optimization

15

Stages of Dispersion Process

Premixing Grinding Depends on- Premixing- Grinding- Letdown

Correct Carbon Black Product

16

• For full color coatings, a high surface area product, which gives a jet color and blue shade

• For tint applications, there is a tradeoff between strength and blue shade. Higher tint products giver a browner shade, lower strength products give a blue shade.

Full Color Performance

17

STSAm2/g

0 50 100 150 200 250 300 350 400

Jetn

ess

Hun

ter

L

3

4

5

6

7

8

9

10

Untreated ProductsTreated Products

STSAm2/g

0 50 100 150 200 250 300 350 400

Blu

enes

sH

unte

r b

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Untreated ProductsTreated Products

JetnessHunter L

3 4 5 6 7 8 9 10

Blu

enes

sH

unte

r b

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.6

Untreated ProductsTreated Products

Tint Color Performance

18

30

60

90

120

0.0 40.0 80.0 120.0 160.0 200.0

Tin

tin

g S

tren

gth

(%

)

STSA (m²/g)

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

0.0 40.0 80.0 120.0 160.0 200.0

Hu

nte

r U

nd

erto

ne

(b)

STSA (m²/g)

-5.00

-4.50

-4.00

-3.50

-3.00

-2.50

-2.00

-1.50

-1.00

-0.50

0.00

0 20 40 60 80 100 120

Hu

nte

r U

nd

erto

ne

(b)

Tinting Strength (%)

Dispersant Choice

19

SurfactantsLow molecular weight dispersing agent which can modify the properties between the pigment and resin solution by lowering their interfacial tension.

Polymeric DispersantsHigher molecular weight dispersing agents, composed of anchoring groups and polymeric chains that stabilize dispersions via a steric stabilization mechanism.

Surfactants Can be Classified by Head Group Type

Anionic – negative chargeSodium dodecylsulfate (SDS) also called sodium lauryl sulfate(C12H25)OSO3NaGood for basic pigment surfaces

Cationic – positive chargeCetyltrimethylammonium bromide (CTAB) (C16H33)N(CH3)3BrGood for acidic pigment surfaces

Nonionic – No chargeOctaethylene glycol monododecyl ether(C12H25)(OCH2CH2)8OHGood for neutral pigment surfaces

Zwitterionic – both postive and negative charge (on different parts of the molecule)Phosphatidylcholine (as seen in lecithin)Good for neutral pigment surfaces

20

Surfactants Can be Classified by Tail Type

Saturated

Unsaturated Monounsaturated

Polyunsaturated

21

Phosphatidylcholine Structure

22

Polymeric Dispersants

Polymeric dispersants are at least a two-component structure which combines the following requirements:

a) Specific Anchor GroupsThe dispersant must be capable of being strongly adsorbed into the carbon black surface via the anchoring groups.

b) Polymer ChainsThe dispersant must contain polymeric chains that give steric stabilization in the required solvent or resin system.

23

Effect of Dispersant Choice : Leather Coating

24

6.27

10.99

6.51

5.565.83

4.89

5.66

0.90

1.85

1.43

1.001.12

0.78

1.01

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

11.00

Reference "Drop In" A B C Y Z

Blu

ness

Hun

ter b

Jetn

ess

Hun

ter L

Effect of Dispersant Choice : WB Automotive

25

3.49

3.02 3.04 2.94

2.61

3.933.64

2.81

-0.42

-0.05 -0.05

0.09

-0.40

-0.18 -0.19-0.08

-0.8

-0.4

0.0

0.4

0.8

1.2

1.6

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Blu

eton

e H

unte

r b

Jetn

ess

Hun

ter

LL b

Effect of Dispersant Loading: WB Automotive

26

2.50

2.70

2.90

3.10

3.30

3.50

3.70

3.90

60 70 80 90 100 110 120 130

Jetn

ess

Hu

nte

r L

Dispersant Amount Wt %

Effect of Dispersant Loading: SB Automotive

27

275

280

285

290

295

300

305

0% 20% 40% 60% 80% 100% 120%

Jetn

ess

My

Dispersant Amount

Summary

28

• The first stage in getting the best from your carbon black, is choosing the right carbon black initially

• Tailor dispersant and resin chemistry to optimize performance

• Ladder study to optimize loading

• MSDS, brochures and other information is available at birlacarbon.com

• The International Carbon Black Association website carbon-black.org also contains useful health and safety information including a users guide

29

Further Information : Thank you