| 摘要 |
PROBLEM TO BE SOLVED: To obtain a thermoplastic polyurethane resin for a magnetic recording medium capable of exhibiting excellent magnetic powder dispersibility and excellent magnetic tape durability by copolymerizing a glycol component of an aromatic polyester diol with 1,6-hexanediol within the range of a specific composition, blending a low-molecular weight glycol having <=300 molecular weight in a molten state, thereby reducing the melt viscosity and enabling the melt polymerization. SOLUTION: This polyurethane resin for a magnetic recording medium is obtained by reacting a polyester diol (component A) comprising an aromatic dibasic acid in an amount of >=80 mol% in an acid component and a glycol component consisting essentially of 1,6-hexanediol in its compounded amount of >=10 and <=50 mol% with a low-molecular diol having <=300 molecular weight (component B) and, as necessary, a polyester polyol (component C) comprising an aliphatic dibasic acid in an amount of >=80 mol%; in an acid component with an organic polyisocyanate compound (component D).
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