Mechanism of Chemical Reactions Involved in Magnetic Coatings

  • R. S. Tu

Abstract

The major binders in magnetic coatings are high molecular weight thermoplastic polyurethane and low molecular weight polyisocyanate. This paper reviews the stoichiometry and kinetics of the isocyanate reactions involved in a typical formulation. It was concluded that the dominant reaction is the condensation of the -NCO groups and water in the formulation with the formation of polyurea as an inter-penetrating network in the polyurethane matrix. The degree of crosslinking of the polyurethane molecules was insignificant.

Keywords

Formaldehyde Dioxide Carbide Hydroxyl Urea 

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References

  1. 1.
    Union Carbide, “Chemical and Plastic Physical Properties”, 1979–80 Edition (F-44086C, 2/79–40M).Google Scholar
  2. 2.
    Union Carbide, “Bakelite Phenoxy Resins for Solution Coatings (F-41521B, 10/78–6M)”.Google Scholar
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    Mobay, “Chemistry for Coatings (3/76)”.Google Scholar
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    J. H. Saunders and K. C. Frisch, “Polyurethane Chemistry and Technology”, Part I, p. 79, Interscience Publishers, New York, 1965.Google Scholar
  5. 5.
    J. Curtis, MTD Project Report, “Isocyanate Reaction Chemistry in Magnetic Tape Formulation — IV”, May 20, 1981.Google Scholar

Copyright information

© Plenum Press, New York 1989

Authors and Affiliations

  • R. S. Tu
    • 1
  1. 1.Magnetic Tape DivisionAmpex CorporationRedwood CityUSA

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