IL434MERSMITH, J. R.
Ryown & Villi_=son Icb.Cc
1600 V1. Hill Street
Louisville, Ky. 402C;1
Time Required: 20 minutes.
ProJection Equipmcnt Required: 35 mm slide 3-1/4 x
4" slide
Opaq,ue~ , Overhead Trnnsparency 8 Irm f iln 16 rn
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Abstract: SOD wora:; or equivalent (Type tiLle of
paper in capitals, Authors, Add-ress
of prineipal author, leave one line and type
abstract vith single spacinZ).
SHREDDED MOUS CELLULOSE ACETATE. A NEW HIGH
IIFR1701,~.,-V,!~CE FILTER MATERIAL
0 - 11. L. Reynolds and J. R.. lla=ersmith
'ROW
Brown & Williamson Tobacco Corp., Louisville,
Kentucky 40201
This paper descrihes a new cellulose acetate based
filter material. The material,
an open cell porous acetate film in the form of
tobacco-like strands, can, as a 25 =1
filter, remove up to 70% of the tar and nicotine
from mainstream smoke at 2 pressure
drop of only 6 cm w.g. This high filtration is
achieved with only 150-eit-of -riterial.
other--acetate filter designs, using cellulose
acetate fibers, require about 300 tip, 01:
material to achieve similar- filtration.
,One way to prepare -the highly porous rnaterial
is to -cast sheets f rom acetone dup~_s
containing ccllulose acetate and cornstarch. This
-is an adaptation of a Metht'd
descri bed by the Electric Storage Battery Co.,
for the preparation of porous polyolef~n
battery separators, (U.S. 2,672,929). After
removal of colvent, the sheets arc shred-lad
to the required dimensions. Expansion of
the.starch, by pressure cooking in water at
about 120'C,. ruptures the walls of the cellulose
acetate matrix.. The cooked starch
is solubilized by enzymatic hydrolysis. An
./-amylase such as Tenase (Miles Lzborate-zie.,
is suitable. Final washing and drying provides an
open cell product with pore diameters
ranging from 2 to 20 microns.
The porosity and surface area of the shreds depend
'on the relative! prop ortions
of starch and ccllulose acetate in the initial
dope. Final porosity increases lrotn
50%. with a 1/1 stArch /acetate tnix to 907. with
a 411 mix. Three parts of starch to'
64 e of acetate provide a porassit~ of 8M. which
is Tietettaiy ft'r 71Y4
efficiency, Material with this porosity'has a
surface area of Abo-ut 1.2 m /g.
'The shredded naterial-may be formed into filter
rods in a similar fashion to
tbAt Which it used to fbft t6badea itito
cigSLtettt9-. Thus, ther Srhreds toay- be put
into the'hoppe-r of a cigarette tftaking machine,
carried through to the garniture,
wrapped ih paper, and cut to the desired length.
Small changes in filter perforvance
.are found by changing the packing density of the
'shred&', their width, and thic?ness.
Rest results arc obtained vith material. cut at 30
cuts pen- inch f rorl a sheet uhich.
before expansion, has a thickness of about 0.04
mm. When formed into filter rods
of 24.6 uim- circunf!erence at a packing density
9f 125 m,,Icc, pressure drop is 2.5
em w.g. for each 10 = of filter length. Such"
filters can reduce tar to 10 -mg when
attached to typical king size U.S. blend
cigarettes.
302058004
BATCo document for Province of British Columbia 19
April 1999