Biodegradable cigarette filter tow and method of manufacture

Abstract

A biodegradable cigarette filter tow includes a mixture of at least two or more natural materials selected from the group consisting of hemp fiber, flax fiber, abaca fiber or pulp, sisal fiber or pulp, wood pulp, and cotton fiber or cotton flock. The mixture may also include regenerated cellulose fibers. The mixture may include a natural binder or may be hydroentangled.

We claim: 
     
         1 . A biodegradable cigarette filter tow, comprising:
 at least two natural fibrous materials, the natural fibrous materials being selected from the group consisting of: hemp, flax, abaca, sisal, wood pulp, and cotton; and   regenerated cellulose fiber.   
     
     
         2 . The filter tow of  claim 1 , wherein the natural fibrous materials include at least one of abaca, sisal and wood pulp. 
     
     
         3 . The filter tow of  claim 1 , further comprising a natural binder. 
     
     
         4 . The filter tow of  claim 1 , comprising:
 0-50% by weight of hemp fiber or hemp filler;   0-50% by weight of flax fiber or flax filler;   0-95% by weight of abaca fiber or abaca pulp;   0-95% by weight of sisal fibers or sisal pulp;   0-50% by weight of wood pulp;   0-50% by weight of cotton fibers or cotton flock;   0-50% by weight of regenerated cellulose fibers; and   0-30% by weight of a natural binder.   
     
     
         5 . The filter tow of  claim 4 , wherein the natural binder is selected from the group consisting of natural latex, vegetable gum, starch based binder, cationic starch binder, carboxymethyl cellulose, and other biopolymer and bio based polymers. 
     
     
         6 . The filter tow of  claim 1 , wherein the natural fibrous materials comprise at least one of hemp and flax material, at least one of abaca, sisal, and wood pulp material, and cotton fiber or cotton flock. 
     
     
         7 . The filter tow of  claim 6 , further comprising a natural binder comprising a cationic starch. 
     
     
         8 . The filter tow of  claim 1 , comprising:
 1-50% by weight of hemp or flax fiber or filler;   1-95% by weight of abaca or sisal pulp or fiber or 1-50% by weight of wood pulp;   1-50% by weight of cotton fiber or cotton flock; and   1-50% by weight of regenerated cellulose fibers.   
     
     
         9 . The filter tow of  claim 8 , comprising:
 5-25% by weight of hemp or flax fiber or filler;   20-50% by weight of abaca or sisal pulp or fiber or wood pulp;   10-30% by weight of cotton flock; and   30-40% by weight of regenerated cellulose fibers.   
     
     
         10 . The filter tow of  claim 9 , comprising 5-25% by weight of hemp. 
     
     
         11 . The filter tow of  claim 9 , comprising no more than 20% by weight hemp or flax filler. 
     
     
         12 . The filter tow of  claim 9 , comprising 30 to 45% by weight abaca, sisal or wood pulp. 
     
     
         13 . The filter tow of  claim 9 , comprising 15 to 30% cotton flock. 
     
     
         14 . The filter tow of  claim 8 , further comprising a natural binder. 
     
     
         15 . The filter tow of  claim 8 , wherein the natural fibrous materials include at least one or more of hemp and flax cut to a mean fiber length of less than 3.5 mm and having a predetermined fiber diameter. 
     
     
         16 . The filter tow of  claim 15 , wherein the fiber diameter is no greater than 500 μm. 
     
     
         17 . The filter tow of  claim 8 , wherein the cotton fiber length is in the range of 250-1000 μm and the cotton fiber thickness is in the range from 10-50 μm. 
     
     
         18 . The filter tow of  claim 1 , wherein the regenerated cellulose fibers have a fiber length in the range from 2 to 6 mm. 
     
     
         19 . The filter tow of  claim 1 , wherein the fibrous materials are formed into a fibrous web having an open bulky structure with a volume density of no greater than 200 kg·m −3  and the fibrous web has an air permeability of greater than 100 cm 3 ·cm −2 ·sec −1  at a differential pressure of 200 Pa. 
     
     
         20 . The filter tow of  claim 1 , wherein the fibrous materials are formed into a fibrous web having an areal density in the range from 25 g·m −2  to 65 g·m −2 . 
     
     
         21 . A biodegradable cigarette filter material comprising at least two or more natural fibrous materials, at least one of the natural fibrous materials being selected from the group consisting of wood pulp, abaca and sisal and at least one other natural fibrous material being selected from the group consisting of hemp, flax and cotton. 
     
     
         22 . The biodegradable cigarette filter material of  claim 21 , comprising a non-woven fibrous web. 
     
     
         23 . The biodegradable cigarette filter material of  claim 21 , further comprising a regenerated cellulose fiber. 
     
     
         24 . The biodegradable cigarette filter material of  claim 21 , further comprising a natural binder. 
     
     
         25 . The biodegradable cigarette filter material of  claim 23 , comprising a mixture of hemp, cotton, regenerated cellulose fiber, and one natural fibrous material selected from wood pulp, abaca and sisal. 
     
     
         26 . The biodegradable cigarette filter material of  claim 23 , comprising a mixture of hemp, cotton, regenerated cellulose fiber, and wood pulp. 
     
     
         27 . A method of making a biodegradable cigarette filter material, comprising:
 dispersing a mixture of fibrous materials in water, the fibrous materials comprising at least two natural fibrous materials selected from the group consisting of hemp, flax, abaca, sisal, wood pulp and cotton in water;   forming the dispersed fiber mixture into a non-woven fibrous sheet in a wetlaid or papermaking machine;   removing excess water from the non-woven fibrous sheet using suction;   adding a natural binder to the fiber mixture prior to or during formation of the non-woven fibrous sheet;   drying the non-woven fibrous sheet; and   forming the non-woven fibrous sheet into cigarette filter tow.   
     
     
         28 . The method of  claim 27 , wherein the mixture of fibrous materials comprises
 0-50% by weight of hemp fiber or hemp filler;   0-50% by weight of flax fiber or flax filler;   0-95% by weight of abaca fiber or abaca pulp;   0-95% by weight of sisal fibers or sisal pulp;   0-50% by weight of wood pulp;   0-50% by weight of cotton fibers or cotton flock; and   0-50% by weight of regenerated cellulose fibers.   
     
     
         29 . The method of  claim 27 , wherein the natural binder is selected from the group consisting of natural latex, vegetable gums, starch based binders, cationic starch binder and carboxymethyl cellulose (CMC). 
     
     
         30 . The method of  claim 29 , wherein the mixture of fibrous material comprises
 5-25% by weight of hemp or flax fiber or filler;   20-50% by weight of abaca or sisal or wood pulp or fiber;   10-30% by weight of cotton flock; and   30-40% by weight of regenerated cellulose fibers.