Cigarette filter and filter material therefor

摘要

A filter material comprises a cellulose acetate fiber tow containing 5-50% by weight of a water soluble material and/or a water dispersible material which are soluble in a solvent which dissolves cellulose acetate and which are not compatible with cellulose acetate. Due to the inclusion of the above-mentioned water soluble material and/or water dispersible material in the cellulose acetate fiber, in the presence of moisture, the fiber surface becomes porous by the elution of this water soluble material and/or water dispersible material from the fiber, and the surface area of the fiber is increased. Consequently, the shape of the cellulose acetate fiber tow is easily broken down, and the decomposability of the fiber by microorganisms and the like is increased. When a cigarette filter is made using this type of filter material, a cigarette filter is obtained which has easy decomposability in the natural environment and particularly in water, in atmospheres which contain large amounts of moisture, and the like.