How to get the Best From Your Carbon Black

1. How to get the Best From Your Carbon Black PNW Coatings Society October 2014

2. Agenda • Review of Carbon Black Fundamentals • Dispersion Process and Optimization • Process • Wetting • Dispersion • Stabilization • Correct Carbon Black Product • Dispersant types • Examples • Summary

3. Review of Carbon Black Fundamentals

4. Four Fundamental Properties of Carbon Black • Fineness • Particle Size Distribution • Structure • Aggregate Size/Shape Distribution • Porosity • Pore Size Distribution • Surface Activity • Surface Functionality Distribution

5. Properties of Carbon Black - Primary Particle Size • 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 Conductex 7055 Ultra 42 nm Raven 410 100 nm Raven 5000 Ultra II 8nm Raven 1255 21 nm

6. Surface area and its influence • 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

7. Carbon Blacks

8. Structure – Oil Absorption Number (ASTM D2414) • 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

9. Effect of Structure on Performance Higher structure (OAN) leads to • Slightly lower blackness and tint strength • Better dispersibility • Higher viscosity and vehicle demand • Higher electrical and thermal conductivity

10. Porosity and its Influence • 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

11. Surface Activity and its Influence • 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 Black as produced Oxidation 950 OC No Oxygen Post treatment adds oxygen groups to the surface

12. Measurement of Surface Activity • 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

13. Oxygen Functionality – Volatile Increasing Acidity

14. Dispersion Optimization

15. Stages of Dispersion Process Premixing Grinding Depends on • Premixing • Grinding • Letdown

16. Correct Carbon Black Product • 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.

17. Full Color Performance

18. Tint Color Performance

19. Dispersant Choice 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.

20. Surfactants Can be Classified by Head Group Type • Anionic – negative charge • Sodium dodecylsulfate (SDS) also called sodium lauryl sulfate • (C12H25)OSO3Na • Good for basic pigment surfaces • Cationic – positive charge • Cetyltrimethylammonium bromide (CTAB) • (C16H33)N(CH3)3Br • Good for acidic pigment surfaces • Nonionic – No charge • Octaethylene glycol monododecyl ether • (C12H25)(OCH2CH2)8OH • Good 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

21. Surfactants Can be Classified by Tail Type • Saturated • Unsaturated • Monounsaturated • Polyunsaturated

22. Phosphatidylcholine Structure

23. Polymeric Dispersants Polymeric dispersants are at least a two-component structure which combines the following requirements: • Specific Anchor GroupsThe dispersant must be capable of being strongly adsorbed into the carbon black surface via the anchoring groups. • Polymer ChainsThe dispersant must contain polymeric chains that give steric stabilization in the required solvent or resin system.

24. Effect of Dispersant Choice : Leather Coating

25. Effect of Dispersant Choice : WB Automotive

26. Effect of Dispersant Loading: WB Automotive

27. Effect of Dispersant Loading: SB Automotive

28. Summary • 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

29. Further Information : Thank you • 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