Author: Approval: Hubert Oggermüller May 2008 VM / Dr. Alexander Risch _____________________ Non-black Fillers in EPDM Extrusion Formulation VM-4/05.2008/06110980 (peroxide cured) HOFFMANN MINERAL GmbH • P.O. Box 14 60 • D-86619 Neuburg (Donau) • Phone (+49-84 31) 53-0 • Fax (+49-84 31) 53-3 30 Internet: www.hoffmann-mineral.com • e-Mail: info@hoffmann-mineral.com Summary Two classes of filler are suitable for extrusion processing, particularly when special profiles must be produced. The products based on Neuburg Siliceous Earth and calcined clay produced the best extrusion properties among the non-black fillers tested. Neuburg Siliceous Earth has a clear advantage here in terms of price to performance ratio. Surface-treated AKTISIL VM 56 wins on cost compared to untreated calcined clay, at the same time providing better tensile strength, a higher modulus and a lower change of elongation at break after ageing. Where emphasis is placed on mechanical properties, combining the active filler with carbon black or precipitated silica (or silicates in the case of non-black applications) is a solution. Here the recipe must be adapted to fit the specific needs involved. Page 1 Non-black Fillers in EPDM Extrusion Formulation (peroxide cured) Test Compound EPDM, 55 % Ethylene, medium diene-content ML (1+8) 125 °C, approx. 821 100 Zinc oxide2 5 Stearic acid 2 Calcium oxide coated by special dispersion agents 80 %³ 10 250/110/75 Filler 0/3/5 Diethylene glycol (DEG), as indicated Paraffinic oil4 60 Triallyl-cyanurate 50 %5 3 Bis(t-butylperoxy-isopropyl)benzene 40 %6 8 Regarding precipitated silica and the different types of precipitated silicate additional compounds with 3 phr DEG were examined. To obtain an adequate cross linking the various hard clays need the use of 5 phr DEG. Curing was carried out in a press at 180 °C. The curing time was t90 + 10 %. Please mind! The following figures show trend analysis, which only can be the basis for specific problems solving. Filler: Precipitated Silica Precipitated Silicates Carbon Black All others Open Mill Batch Temperature Time of mixing Extruder Temperature of barrel Temperature of head Applied in this test compound: (1) (2) (3) (4) (5) (6) Vistalon 7500 , Exxon Zinkoxyd aktiv, Bayer Kezadol GR, Kettlitz Sunpar 2280, Sun Oil Company TAC 50 %, Kettlitz Perkadox 14/40, Akzo Page 2 Loading: 75 phr 110 phr 110 phr 250 phr 150 x 300 mm 500 cm³ 50 °C 15 to 20 min d = 30 mm L/D = 15 70 °C 110 °C Contents Index of Compound Costs Page 4 Properties of Raw Compound Mooney Viscosity ML (1+4) at 120 °C Mooney Scorch t5 (ML) at 120 °C Extrudability (Quality), Rating Garvey-Profile Extrudability (Quality), Torque of Extruder Extrudability (Quantity), Maximum of Extrusion Speed Extrudability (Quantity), Torque of Extruder Rotorless Cure Meter, t5 at 180 °C Rotorless Cure Meter, t90 at 180 °C Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Properties of Vulcanizate Tensile Strength Elongation at Break Modulus Hardness Tear Resistance Rebound Elasticity Abrasion Compression Set Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Properties after Air Ageing Change of Tensile Strength Change of Elongation at Break Change of Hardness Change of Tear Resistance Page 21 Page 22 Page 23 Page 24 Annex Pictures of extrusion profiles Page 25-27 Our technical service suggestions and the information contained in this report are based on experience and are made to the best of our knowledge and belief, but must nevertheless be regarded as non-binding advice subject to no guarantee. Working and employment conditions over which we have no control exclude any damage claims arising from the use of our data and recommendations. Furthermore, we cannot assume any responsibility for any patent infringements which might result from the use of our information. Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Annex: Extrusion Profiles Page 25 Page 26 Page 27