FILTER MEDIUM AND CIGARETTE FILTER MADE WITH THE USE OF THE SAME

摘要

A filter medium comprising a tow of cellulose acetate fibers which contains 5 to 50 % by weight of water-soluble substances and/or water-dispersible substances soluble in a solvent for cellulose acetate and incompatible with cellulose acetate. The water-soluble substances and/or water-dispersible substances thus contained in the tow are separated and exuded from the fibers in the presence of water. As a result, the surface of each fiber becomes porous and the surface area of the fiber is enlarged. Thus, the configuration of the tow can easily be broken, which facilitates the degradation thereof by microorganisms, etc. A cigarette filter produced by using the filter medium has a high degradability in the natural environment, in particular, in a highly humid atmosphere, in water, etc.