| 摘要 |
PURPOSE:To obtain a magnet with memory properties which can retain a desired shape freely by blending hard ferrite powder in a shape memory polymer and then magnetizing it. CONSTITUTION:A shape memory polymer is a polyurethane made by blending bifunctional diisocyanate (2,4-toluene diisocyanate, etc.), bifunctional polyol (polypropylene glycol, etc.), and bifunctional chain extender (ethylene glycol, etc.) including an active hydrogen base in a molecular ratio of diisocyanate: polyol: chain extender = 2.00-1.10:1.00-0.10 and by polymerizing using the prepolymer method. Approximately the same amount of NCO group and an OH group are contained at the end terminal, the glass transition point is -50 to 60 deg.C, and a crystallinity is 3-50weight%. Powder such as Ni and Co (grain diameter: 10mum-0.3mm) of 5-40 volume % is added to this polymer and the strength of an external magnetic field is determined for obtaining a desired residual magnetization matching the grain diameter, thus obtaining a magnet with shape memory properties. |
