| 摘要 |
PURPOSE:To increase the water resisting performance, by forming a barrier to the water or sweat going to the inside of a watch by means of a magnetic fluid which is provided to the external operation part like a crown, a switch button, etc. or to the outer circumference part of the back or the battery cover. CONSTITUTION:The surface of the ferromagnetic particle like 100-200Angstrom magnetite, manganese ferrite, nickel ferrite, etc., is coated with a surfactant of long chain unsaturated fatty acid group such as oleic acid, linolic acid, etc. Such particles are dispersed into a solvent such as aliphatic hydrocarbon, aromatic hydrocarbon, water, etc. with use of an anion or nonionic surface active agent to obtain a colloid solution. This solution is a magnetic fluid having both the solid state properties of the ferromagnetic properties and the liquid properties of the fluidity. This fluid 6 is fixed tightly to the waterproof part of a crown 9 or a switch button 13 by means of a magnet 5. In this case, the magnet 5 can be set at the side of the watch case or the side of the crown. |
