| 摘要 |
PURPOSE:To perform electrification without generating dielectric breakdown or voltage drop, by filling interstices between fibers and coating said fibers with a substance having dielectric constant equal to that of an air filter constituting fiber before performing electrification by a corona discharge apparatus. CONSTITUTION:A large amount of air spaces are present in a bulky fiber aggregate fromed by bonding constitutional fibers 1 with each other by a bunder. These spaces are filled with a dielectric substance 2 having dielectric constant almost equal to that of said fibers 1 as well as the fibers 1 are coated therewith to constitute a filled fiber aggregate 3 having dielectric constant almost uniform throughout the same. This aggregate 3 is heat treated at temp. randing from the secondary transition temp. of the constitutional fibers 1 to the m.p. thereof and, thereafter, a DC current of 1-10kV is applied to generate corona discharge and electrification is performed while the filled substance 2 having equal dielectric constant is removed by high pressure air or a solvent to constitute an electret filter. |
