Nissin Chemical Industry Co., Ltd.

Shin-Etsu Chemical Co., Ltd.

Masahiko Ikka

Hiroto Sugahara

Kazuaki Sakaki

Tetsuya Kume

Tetsuya Ohashi

Hirochika Naganawa

Kojiro Shimojo

Yoshiyuki Yasuhara

Tomoki Horiguchi

A rare earth metal extractant in the form of a dialkyl diglycol amic acid is synthesized by reacting diglycolic anhydride with a dialkylamine in an aprotic polar solvent, with a molar ratio of dialkylamine to diglycolic anhydride being at least 1.0, and removing the aprotic polar solvent.

Synthesis of rare earth metal extractant

A rare earth metal extractant in the form of a dialkyl diglycol amic acid is synthesized by reacting diglycolic anhydride with a dialkylamine in a synthesis medium. A molar ratio (B/A) of dialkylamine (B) to diglycolic anhydride (A) is at least 1.0. A non-polar or low-polar solvent in which the dialkyl diglycol amic acid is dissolvable is used as the synthesis medium.

Proposed is a novel vinyl chloride-based copolymeric resin suitable as an electron beam-curable binder resin for forming a magnetic recording layer of a magnetic recording medium. The binder resin is a vinyl chloride-based copolymeric resin containing monomeric units having a hydroxy group which is reacted with an ethylenically unsaturated monomeric compound having an isocyanato group in a molecule and then subjected to a modification reaction with an amine compound. The magnetic recording medium, e.g., magnetic recording tape, prepared by using the binder resin is excellent in the surface properties such as gloss and traveling resistance as well as in the magnetic properties such as residual magnetic flux density and squareness ratio of the magnetic hysteresis loop.

Magnetic recording medium

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Echizen, Japan

Masahiko Ikka