BOND MAGNET AND COMPOSITION FOR BOND MAGNET

To provide a composition for a bond magnet, by which a bond magnet superior in both of heat resistance and magnetic characteristic can be obtained while ensuring moldability.SOLUTION: A composition of the present invention comprises one or more kinds of rare earth magnet particles and a binding resin, and is used for manufacturing a bond magnet. The rare earth magnet particles include at least Nd-based magnet particles in which a rare earth element is Nd, and the total amount of the rare earth magnet particles is 90-95 mass% to a whole amount of the composition. The binding resin consists of polyamide 66(PA66) in which a total amount of terminal groups consisting of carboxyl and amino groups is 175 mmol/kg or less to a total amount of the binding resin. Even if PA66 of which the total amount of the terminal groups is adjusted touches the rare earth magnet particles serving to bring about a catalyst effect, the start of the increase in viscosity is delayed. So, the stable moldability can be ensured even if the content of the rare earth magnet particles is large. A bond magnet which can be obtained from the composition like this would be superior in both of magnetic characteristic and heat resistance.SELECTED DRAWING: Figure 2A 【課題】成形性を確保しつつ、耐熱性と磁気特性の両方に優れたボンド磁石が得られるボンド磁石用の組成物を提供する。【解決手段】本発明の組成物は、一種以上の希土類磁石粒子と結合樹脂からなり、ボンド磁石の製造に用いられる。希土類磁石粒子は、希土類元素がＮｄであるＮｄ系磁石粒子を少なくとも含み、希土類磁石粒子の総量は、組成物全体に対して９０〜９５質量％である。結合樹脂は、カルボキシル基とアミノ基からなる末端基の総量が結合樹脂全体に対して１７５ｍｍｏｌ／ｋｇ以下のポリアミド６６（ＰＡ６６）からなる。末端基の総量が調整されたＰＡ６６は、触媒作用を果たす希土類磁石粒子と接触しても、増粘開始が遅延され、希土類磁石粒子の含有率が多い場合でも、安定した成形性が確保される。このような組成物から得られるボンド磁石は、磁気特性と耐熱性の両方に優れる。【選択図】図２Ａ