Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Description
Ventllated Filter Tip Cigarette
Technical_Field
The present invention relates to tobacco products
and more particularly, to cigarettes, cigars, and other
similar products including a tobacco column within an
outer wrap formed of combusible material and a filter
member mounted coaxially at one end of the tobacco column
for filtering the mainstream smoke as the tobacco product
is burned.
Background Art
Tobacco products of the types considered herein
including a filter member are known to be prior art. To
this end, it has been known for many years tha~ certain
ingredients normally found in the mainstream smoke of a
burning tobacco column may be filtered by means of a
filter and filter material mounted at one end of the
tobacco column. The filter, thus, provides a barrier to
those ingredients prior to entering the mouth of the user.
It is also known in the prior art that a secondary flow
of air may be introduced to the mainstream smoke for
purposes of diluting the mainstream smoke. The secondary
flow of air for diluting the mainstream smoke, and at
the same time providing a cooling effect, may enter by
- a plurality of perforations formed in and along the
combustible wrap of the tobacco column. The perforations,
also, may be located within the filter. In this connec-
tion, the filter in the form of a body or filter material
is surrounded by a composite wrap including an inner
layer, or plug wrap of porous paper and an outer coextensive
wrap comprising a wrap oE non-porous tipping paper having
a perforated area~ Typical of a filter of this type, is
the filter disclosed in Davi~ patent No. 3,797,975.
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The prior art also includes a form of filter
including a body of filter material surrounded by a
composite wrap including an inner layer, or plug wrap
of porous paper and an outer wrap of non-porous tipping
paper extending from one end of the filter, the end
which is entered into the mouth of the user, along only
a length of the plug wrap to expose an area of the
inner wrap. Typical of a filter of this type, is the
filter disclosed in Tucker patent No. 3,410,275.
Filters of either the aforementioned types would
probably deliver mainstream smoke with "tar" levels of
a normal range (15-25mg. per cigarette). However, the
industry now seeks to provide a tobacco product which
delivers mainstream smoke with appreciably lower levels
of "tar".
Disclosure of the Invention
The present invention is directed to a tobacco
product including cigarettes, cigars and similar smoking
articles having a tobacco column supported by an outer
combustible wrap and a filter of a design whereby free
and controllable levels of flow of ambient air, comprising
25 a secondary flow, may be drawn into the filter and the
mainstream smoke to reduce the degree of puff, dilute and
cool the mainstream smoke. The particular design of the
filter is such that restrictions to the air flow may be
substantially obviated. The result is to maintain the
30 effectiveness of the filter. Further, the filter is of
a construction suitable for use in the fabrication of a
cigarette in accordance with generally recognized manu-
facturing procedures, as well as with apparatus for that
purpose, and the filter of the present invention is
; 35 constructed in a manner such that the cigarette may
deliver a desired level of ''tar" by a variation in makeup
of what may be characterized as "maintenance means" for
supporting the filter material in the form of a cylindrical
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rod-like body. Such variation, as will be discussed,
includes variation in the porosity of the inner wrap or
plug wrap and/or the area of the maintenance means which
is exposed to ambient air and/or the inclusion of a
plurality of perforations within the exposed area.
According to the invention, a filter for a tobacco
product or the like comprises a body of filter material
having a first end adapted to be placed in the mouth of
the user and a second end adapted to be disposed coaxially
at one end of the column of the tobacco product or the
like. Means are provided for maintaining the filter
material in the cylindrical rod-like form, and for
permitting an ingress of ambient air into the filter
material so as to provide mainstream smoke dilution on
the order of 25 to essentially 100%. Air from the secon-
dary flow mixes with the mainstream smoke entering the
filter mate~ial from the tobacco column to dilute and
cool the mainstream smoke as it moves toward the first
end of the filter. A wrap of paper, or tipping wrap
forms an outer wrap that surrounds the maintenance means
at the first end and along a length of the body of filter
material. The tipping wrap serves to ensure lip release
for the smoker. The tipping wrap, preferably, is formed
of a substantially non-porous material to prevent or
deter ingress of air into the filter material except
through that portion of the maintenance means which is
exposed, as previously discussed.
The invention contemplates several forms of
maintenance means. Thus, the maintenance means may
comprise an inner wrap or plug wrap having a uniform
porosity. The plug wrap, additionally, may be provided
with a plurality of perforations located in at least the
area not surrounded by an outer or tippinq wrap. It is
also contemplated that the filter material may be self-
supporting. As such the need for the aforementioned innerwrap or plug wrap is obvi~ted. To this end, the filter
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material may be formed of polyurethane or other polymer
as an open cell foam, or the filter material ma~ be formed
of cellulose acetate tow whose integrity in the rod-
li~e form is maintained by a bonding agent, such as a
plasticizer. The maintenance means provides a porous
outer surface permitting dilution of the mainstream smoke
up to essentially lO0~.
The present invention also envisions a
cigarette including a tobacco column and a filter member
of the type previously discussed. A further band of
paper is utilized to join the filter and the tobacco
column. The band of paper, as the aforementioned outer
15 wrap, may be non-porous to prevent or deter ingress of
air into the tobacco column and the filter material, and
may be of any reasonable width to support the tobacco
column. Thus, a variation of width of the paper band,
assuming the width of tipping wrap remains constant,
20 will serve to vary the exposed area of maintenance means
around the circumference of the body of filter material.
The exposed area may have an axial width of between
about l mm and about 30 mm or more.
Brief Descri~tion of the Drawing
26
Fig. l is a view in elevation of a cigarette
including a wrapped tobacco column and a filter member
mounted at one end of the column;
Fig. 2 is a view in elevation of a cigarette
including a wrapped tobacco column and a filter member
mounted at one end of the column wherein the body of
filter material is wrapped by an inner wrap of a porous
paper; and
Fig. 3 is a view similar to Fig. 2 wherein the inner
wrap of porous paper includes a plurality of perforations.
Best Mode for Carrying_Out the Invention
The present invention relates to a tobacco product
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10, such as a cigarette including a column of tobacco
12 and a filter 14. Both the filter and the tobacco
column are o~ rod-like form and a combustible wrap 16,
as conventional, supports the tobacco column.
The filter includes a body of filter material
which may be any one of cellulose acetate, paper, a
polyolefin, a polyurethane or other polymeric foam, or
other filter material, as desired. In the form of the
invention wherein the filter material comprises a
polyurethane foam, the foam preferably will be an open
cell foam, and preferably it will be extruded or other-
wise formed to the rod-like form. Preferably, however,
15 the filter material is cellulose acetate.
The filter 14 and the tobacco column 16 are located
in abutting end-to-end disposition and a band 18 is used
to connect the units. Thus, the band will encircle one
end of each of the filter and tobacco column so that the
20 mainstream smoke from the burning end of the tobacco
column may pass into the filter material to filter
certain particulate matter, such as tars, from the main-
stream smoke which enters the mouth of the user. A
second band 20 may be received around the other end of
25 the filter that is, the mouth end, to ensure lip release
for the smoker.
The bands 18, ~0 may be formed of conventional
non-porous tipping paper or may be formed of a paper having
porous characteristics or formed of non-woven material
30 having suitable characteristics.
In the form of the invention illustrated in Fig. 1,
the body of filter material which may be cellulose
acetate is self-supporting in a rod-like configuration.
The self-supporting characteristic of the filter material
35 is derived through setting of the bonding agent, such
as a plasticizer used during the manufacturing process.
The plasticizer may be glycerol triacetate, tri(ethylene-
glycol) diacetate or other plasticizer of similar nature.
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Glycerol triacetate is preferred and the plasticizer is
- used in an amount sufficient to ensure the self-supporting
integrity of the filter material.
Fig. 2 represents a form of the invention wherein
an inner wrap 22 is disposed around the filter material.
The inner wrap or plug wrap may be paper or non-woven
material. Preferably, the inner wrap is characterized
by a paper having a porosity of from about 300 to about
50,000 cc/min/cm2 at a pressure equal to 10 cm water
(Coresta units) to permit the ingress of air to provide
mainstream smoke dilution on the order of 25 to essen-
tially 100%. The tobacco product lOa, like the tobacco
product of Fig. 1, includes a tobacco column 12, a
combustible wrap 16 for the tobacco column and a filter
14a. The bands 18, 20 of Fig. 1, may be employed to
mount the filter to the tobacco column and to provide a
tipping to ensure lip release for the sMoker, respectively.
In a third form of the invention, see Fig. 3, a
tobacco product lOb similarly includes a tobacco column
12, a combustible wrap 16 for the tobacco column and a
filter 14b. The filter includes a body of filter material
and an inner wrap 22 surrounds the filter material. In
25 this form of the invention, a plurality of perforations
24 are provided in the inner wrap, at least within the
region between bands 18, 20 which comprises an exposed
area "A" (see Figs. 1, 2 and 3). The perforations may
be arranged in any particular pattern in the inner wrap,
30 as for example in one or more circular rings. Preferably,
each perforation is equidistantly spaced from adjacent
perforations around each ring. The area of each perfor-
ation may be within the range of about 0.01 mm2 to about
0.50 mm2 to provide a path of ingress of air of the
35 secondary flow which.offers substantially less resistance
than the resistance to flow offered by the inner wrap
throughout the non-perforated region. The perforations
may be provided mechanically, electrostatically, by means
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of a laser process, by combinations of processes and
others as may be conventional.
According to the invention, the exposed area "A"
ex-tends entirely about the body of filter material and
throughout the axial length between the edges of the
tipping bands 18, 20. The length of the body of the
filter material may be about 20 to S0 mm and band 20
10 may extend throughout a length of about 10 mm to about
20 mm toward band 22. To this end, the axial length of
the exposèd area may be about 1 mm to about 30 mm or
more and have a surface area of about 25 mm to about
750 mm2. In this discussion, the term "maintenance
15 means" is to be interpreted as including the usual
plasticizer employed in the process of supporting the
filter material in rod-like form, the polyurethane or
other self-supporting polymeric foam of open cell type
and the inner wrap of plug wrap either of Fig. 2 or Fig.
20 3. Further, the total area of perforations may be
between about 0.1 mm to about 100 mm whereby about 25
to about 100~ of the secondary flow will enter the filter
material through the perforations.
Practice of the invention will become more apparent
25 from the following examples.
Examples 1-7
A series of seven lots of filter rods were manu-
factured with a standard cellulose acetate filter tow,
30 8 denier per filament/35,000 total denier, utilizing
ma1ntenance means or plug wrap varying in porosit~ from
essentially impermeable to 36~000 Coresta units (cc/min/
cm2). The 100 mm filter rods were made at a pressure
drop of 11 cm of water as measured on an absolute type
35 pressure drop instrument with total encasement of the
filter rods.
Filter tips were attached to tobacco columns,
consisting of a standard cigarette tobacco blend and
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standard cigarette paper, with a band of paper employed
to attach the filter tip to the tobacco column. A wrap
of paper tipping was applied at the mouth end to ensure
lip release for the smoker as previously disclosed.
Examples 1-6 in the following table were tested for
"tar" delivery in accordance with the standard procedure
of the Federal Trade Commission. Twenty cigarettes in
groups of 5 from each example were smoked by passing 35
cc of air per puff through the tobacco column at the
rate of one puff of 2 seconds duration once a minute.
The cigarettes were burned to a 33 mm butt length.
With reference to Examples 4 and 5, there is
demonstrated that "tar" delivery may be varied by keeping
the porosity of the inner wrap constant and varying the
width of the exposed area.
In Example 7, since the "tar" delivery is too low
to be measured accurately by the standard methods, a
spectrophotometric procedure based on that published by
Sloan, C.H. and J.G. Curran, Research Laboratories
(Tennessee Eastman Company, Publication No. FTR-62
7'
(1980) was used.
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