| OBJECT: |
Final dispersion of preground Iron Oxide into resin/solvent solution for coating magnetic tape.
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PROBLEM:
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Make excellent dispersion without causing flocculation. Dispersion of entire pigment amount into the resin followed by addition of the solvent creates too high a viscosity. If pigment is first dispersed into solvent, flocculation occurs. |
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RESULT:
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Overcome the problems by following the steps below precisely. Place mixer into solvent and operate in down-mode. Add 1-2% resin into vortex. Add pigment until material starts to flocculate (gets puffy). Stop pigment addition and add just enough resin to reduce viscosity and flocculation. Then, add remaining pigment. Finally, add remaining resin. Reverse mixer to up-mode and complete dispersion. Work in jacketed vessel - keep cool. |
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AB MIXER:
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CJ-4B mixer. Production equipment was Model C-2 mixer 33" immersion, 7.5 HP explosion proof motor.
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EQUIPMENT REPLACED:
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Propeller Mixers |