TECHNICAL BULLETIN - Cancarb

1 1702 Brier Park Crescent , Medicine Hat, AB, Canada, T1C 1T9 Phone Fax BULLETINEPDM CompoundsThermax medium thermal carbon black N990 is manufactured by the thermal decomposition of natural gas. The thermal process provides a unique carbon black characterized by a large particle size and low structure. Thermax is widely used in applications that require excellent dispersion, superior heat, oil and chemical resistance and demanding dynamic properties. The large particle size (low surface area) and low structure allow for low compression set, high rebound and low viscosity, maintaining the inherent elastomeric properties of the rubber compound. As a non-reinforcing black, thermal black is often blended with furnace carbon blacks and/or mineral fillers to achieve cost reduction and specific physical properties in the rubber can be used in all polymers and is commonly used in elastomers such as NBR, EPDM, HNBR, ACM, FKM and ECO.

2 High loadings of Thermax are possible, while maintaining low viscosity and physical properties such as low compression set, thereby allowing manufacturers to reduce compound the case of EPDM, the inert surface chemistry and unique physical properties of Thermax N990 provide for excellent chemical compatibility with EPDM, allowing for high loadability, good dispersion and excellent surface properties in extrusions. Thermax N990 provides excellent oil and chemical resistance to EPDM and helps to improve the overall aging of Thermax N990 in EPDM Compounds Compound extension for cost reduction and improved aging properties Superior surface finishes due to lowest grit contamination and excellent dispersibility Low viscosity compounds beneficial in corner moldings and other difficult shapes Low gloss grey finish arising from the methane gas feedstock and the thermal decomposition production process Low compression set and superior dynamic properties Excellent dispersibility resulting in consistent heat transfer throughout the extrusion and uniform curingApplicationsEPDM compounds filled with Thermax N990 are used for applications such as.

3 Extruded profiles sponge and solid weather strip Tubing, hose Diaphragms, boots, molded goods, tarp straps Engine mounts, anti-vibration products Roofing membranes Roll coverings Cable insulation Effect of Type of Carbon Black in EPDM at Equal HardnessThe following table (DuPont data) demonstrates the effect of four different types of standard carbon blacks in an EPDM compound at equal hardness. As shown, Thermax N990 can be loaded at more than double the amount of FEF-N550 carbon black, while still maintaining lower Mooney viscosity at equivalent Brier Park Crescent , Medicine Hat, AB, Canada, T1C 1T9 Phone Fax 1: Effect of Different Types of Carbon Black in EPDM at Equal Hardness1(20 phr paraffinic oil)Type of Carbon Black MT N990 SRF N774 FEF N550 HAF N330phr 130 85 60 50M.

4 Viscosity, ML, 1 + 4 @ 100 C 76 80 84 84 Hardness 66 67 65 62300% Modulus, MPa , MPa (%) 520 420 430 460 Tear Strength, Die B, kN/m 19 29 32 28 Source: Dupont Dow, Cured 20 minutes @ 160 C, Formulation: Nordel 1070 100, Zinc Oxide 5, Stearic Acid 1, Paraffinic Oil 20, MBT , TMTM , Sulphur Extended EPDM CompoundsThe following data shows the effect of increasing the volume of Thermax N990 carbon black in an EPDM Dow TECHNICAL Information : Selecting a Filler, 19961702 Brier Park Crescent , Medicine Hat, AB, Canada, T1C 1T9 Phone Fax 2.

5 Effect of Thermax N990 Loading in EPDM (40 phr oil)FormulationNordel 1070 N990 Acid Oxide 4240

6 PropertiesViscosity, ML 1 + 4 @ 100 C 46 48 61 74 90 Mooney Scorch, t5 @ 121 C >30 >30 29 26 24 Rheometer, 166 C, 3 C arc, Hz, 0 preheatMH PropertiesCured.

7 Tc90 + 5 minutes @ 166 C 18 18 18 17 17 Hardness 51 52 61 69 70100% Modulus, MPa Modulus, MPa Modulus, MPa -Tensile Strength, MPa Elongation (%) 610 640 620 515 285 Tear Strength, Die C, kN/m Set, Method B, 70 hours @ 100 C, cured + 15 minutesCompression Set (%) Rebound, cured + 20 minutes, % rebound@ 0 C 56 53 48 40 33@ RT 63 60 52 46 39@ 100 C 68 67 62 59 54 Aged in Air, 168 hours @ 150 CHardness.

8 Pts change 14 23 26 22 25 Tensile, % change 18 3 8 65 83 Elongation, % change -61 -69 -85 -89 -88 Dynamic Properties, MER 1100, 5% static deformation, 2% dynamic deformationTan Delta @ 0 C Delta @ 25 C Delta @ 100 C Brier Park Crescent , Medicine Hat, AB, Canada, T1C 1T9 Phone Fax Conductivity and Thermax N990 in EPDMA large average particle size and a low level of particle agglomeration characterize Thermax N990.

9 These unique properties result in the lowest amount of inherent conductivity in the carbon black. Thermax N990 is therefore used in applications that require higher levels of volume resistivity, such as radiator hose, weather strip and gaskets. Table 3 provides the results of an evaluation of the dry resistance in ohms of four different grades of carbon N990 carbon black is shown to have substantially higher electrical resistance as compared to the other blacks. This is due to the lower level of particle agglomeration, which prevents electron tunneling along particle chain paths. Resistance for the N650 and N550 is significantly lower as these are very high structure blacks characterized by chain-like agglomeration. The N762 showed abnormally low levels of resistance in spite of it having a lower level of agglomeration than the N650 and should be noted that the results provide the dry resistance of the carbon black and not the volume resistivity.

10 The results therefore provide the relative hierarchy of the resistivity of the carbon blacks and are indicative of how the carbon black would perform relatively when incorporated into an elastomer. Caution is needed in interpreting the performance of the carbon blacks in a rubber compound, as the loading, the polymer and cure system, degree of dispersion, oil content and other factors can all influence the final resistivity 3: Carbon Black Resistance (ohms), corrected, average of 3 samplesGrams N990 N762 N650 N55010,000 .2881 .5371 .398715,000 .8170.