| 摘要 |
<p>1,071,280. Magnetic compositions. AMPEX CORPORATION. April 7, 1966 [May 10, 1965], No. 15649/66. Heading H1H. The binder for a recording tape comprises 75-85% of a partially hydrolysed copolymer of vinyl chloride and vinyl acetate, and 15-25% of a urea formaldehyde resin. A solution of the binder may be added to a dispersion of magnetic particles, e.g.γ-Fe 2 O 3 , in a solvent, and mixed, e.g. in a ball mill, then coated on to a backing, dried at 175‹ F. then 225‹ F., spooled, and cured at 80‹ C or 100‹ C. The solvent may be toluene and methyl ethyl ketone. The backing may be a plastic, e.g. polyethylene terephthalate, cellulose acetate, or polypropylene, paper, glass or metal. The dispersion may also include carbon black, phenyl mercuric oleate, licithin, silicones, and lead phosphite.</p> |
