The invention relates to hard magnetic films made of a polymer matrix and hard magnetic powder particles distributed therein. The films have a thickness of preferably 100 to 500 .mu.m and are flexible. They can be produced by using a casting method and are suited, for example, as hard magnetic components in miniature motors, polarized relays or sensors.
A magnetic roller may comprise a magnetized outer surface and an internal chamber. A temperature control system may be in communication with the internal chamber, and a fluid capable of heat transfer may circulate within the internal chamber and the temperature control system. The magnetic roller may be used to produce magnetic sheets having magnetizable particles that are aligned according the a magnetic field generated by the magnetic roller. The magnetic sheet may be provided in a pliable form wherein magnetizable particles may shift orientation when exposed to the magnetic field. Heat may be transferred between the sheet and the magnetic roller to cause solidification of the magnetic material and prevent dealignment of the magnetic particles.
A method of forming a magnetic assembly having at least one magnetic layer having dimensions of thickness, width and length, and at least one printable substrate layer having dimensions of thickness, width and length, including the steps of providing a molten magnetic composition including about 70 wt-% to about 95 wt-% of at least one magnetic material and about 5 wt-% to about 30 wt-% of at least one thermoplastic binder, forming the magnetic composition into a magnetic layer at an elevated temperature and directly applying the magnetic layer at an elevated temperature to a first surface of a printable substrate layer wherein. An adhesion promoting composition may be further provided between the magnetic layer and the printable substrate layer for improving adhesion between the magnetic layer and the printable substrate layer.
A process of making a magnetic assembly having at least one magnetic layer and at least one printable substrate layer including the steps of providing a magnetic composition comprising about 70 wt-% to about 95 wt-% of at least one magnetic material and about 5 wt-% to about 30 wt-% of at least one thermoplastic binder, forming the magnetic composition into a magnetic layer, and directly applying the magnetic composition at an elevated temperature in molten form to a printable substrate layer, and to the magnetic composition and any articles made therefrom.
