| 摘要 |
PURPOSE: To obtain an electret polyolefin split fiber filter which exhibits scarcely decrease in particle collecting efficiency after being used at high temp. and for a long time. CONSTITUTION: An electret filter is obtd. by making a polyolefin split fiber with a surface aluminum number concn. to the carbon number on the surface of the split fiber (Al/C) measured by means of an X-ray photoelectron spectrometry method of at least 0.01% to an electret. By making the surface aluminum number concn. (Al/C) of the polyolefin split fiber large like this and as the result, by making attenuation of the amt. of electric charge after making the polyolefin to be an electret small, it is possible to obtain an electret filter which exhibits little decrease in particle collecting efficiency after being used at high temp. and for a long time. |
