Light colored magnetic rubber

Abstract

A rubber-like flexible permanent magnet comprised of a mixture of granular, high coercivity, permanent magnet material and a rubber-like flexible binder material. A substantial e.g. 90 percent amount of the permanent magnetic material have a grain size of from 0.125 to 0.3 mm. More magnetic material may be used with the same flexibility. Light colored powders such as titanium oxide, or aluminum can be added or the grains coated with a metallic layer using vacuum deposition or a chemical bath deposition to make the final magnet light in color.

Having thus described my invention, I claim: 
     
       1. A light colored, rubber-like flexible permanent magnet comprised of a mixture of a rubber-like flexible binder, a permanent magnet material of high coercivity, as e.g., barium-, strontium-, or lead ferrite powder, and a material capable of giving the magnet a light color said permanent magnet material consisting essentially of relatively coarse grains having a grain size of 0.06 - 0.35 mm, the grain size mainly ranging from 0.1 - 0.3 mm, and the proportion of fine and finest permanent magnet powder particles, with respect to the grain size, being minimized to a negligibly small amount. 
     
     
       2. The permanent magnet according to claim 1 wherein the total volume of powdered permanent magnet material is composed of a proportion of less than 5 percent by volume of grains having a grain size of 0.1 mm and less, 30-50 percent by volume of grains having a grain size of 0.1 - 0.2 mm, 30-50 percent by vol. of grains having a grain size of 0.2 - 0.3 mm, and 5-10 percent by vol. of grains having a gain size of 0.3 - 0.35 mm. 
     
     
       3. The permanent magnet according to claim 1 wherein the light colored material comprises 2-15 percent by vol. of finely divided metal powder, as e.g., aluminum powder. 
     
     
       4. The permanent magnet according to claim 2 wherein the light colored material comprises 2-15 percent by vol. of finely divided metal powder, as e.g., aluminum powder. 
     
     
       5. The permanent magnet according to claim 1 wherein the permanent magnet particles are provided with a colored coating, as e.g., of nickel, cadmium, copper, said coating being effected by a chemical process. 
     
     
       6. The permanent magnet according to claim 1 wherein the permanent magnet powder particles are coated with aluminum by means of vapor plating in a vacuum. 
     
     
       7. The permanent magnet according to claim 2 wherein the permanent magnet particles are provided with a colored coating, as e.g., of nickel, cadmium, copper, said coating being effected by a chemical process. 
     
     
       8. The permanent magnet according to claim 2 wherein the permanent magnet powder particles are coated with aluminum by means of vapor plating in a vacuum. 
     
     
       9. The permanent magnet according to claim 1 wherein the proportion of fine and finest permanent magnet powder particles, with respect to the grain size, is removed. .Iadd. 10. A rubber-like flexible permanent magnet comprised of a mixture of a rubber-like flexible binder and a permanent magnet material of high coercitivity, as e.g., barium-, strontium-, of lead ferrite powder, said permanent magnet material consisting essentially of relatively coarse grains having a grain size of 0.06-0.35 mm, the grain size mainly ranging from 0.1-0.3 mm, and the proportion of fine and finest permanent magnet powder particles, with respect to grain size being minimized to a negligibly small amount. .Iaddend..Iadd. 11. The permanent magnet according to claim 10 wherein the total volume of powdered magnet material is composed of a proportion of less than 5 percent by volume of grains having a grain size of 0.1 mm and less, 30-50 percent by volume of grains having a grain size of 0.1-0.2 mm, 30-50 percent by volume of grains having a grains size of 0.2-0.3 mm, and 5-10 percent by volume of grains having a grain size of 0.3-0.35 mm. .Iaddend..Iadd. 12. The permanent magnet according to claim 10 wherein the proportion of fine and finest permanent magnet powder particles, with respect to grain size, is removed. .Iaddend.