Acrylate copolymers, and magnets using them as binder.

摘要

An acrylate copolymer is made from an alkyl acrylate and a salt of 2-acrylamido-2-methylpropane sulfonic acid (AMPS). The copolymer is suitable for blending with magnetic particles, e.g. of ferrite material, to make a flexible permanent type magnetic composition. The polymer can be loaded with a large amount of magnetic particles. A carboxylated ethoxyl alkyl phenol surfactant may be used which provides good processability and permits a blend of the magnetic particles with the emulsion acrylate copolymer to be precipitated from a latex solution by high shear mixing. Flexible high magnetic energy magnets can thus be made and utilized in various applications such as refrigerator doors, electrical motors, and the like.