CA1168544A - Ventilated filter tip cigarette - Google Patents

Abstract

Ventilated Filter Tip Cigarette Abstract A tobacco product (10, 10a, 10b) such as a cigarette having a wrapped tobacco column (16) and a filter (14, 14a, 14b) of filter material located in end-to-end relation with the tobacco column to filter constituents of the mainstream smoke. Means (Figs. 1, 2, 3) to provide dilution of mainstream smoke from 25 to essentially 100% are provided for maintaining the filter material in a cylindrical rod-like outline. An outer wrap (20) which surrounds the filter extends from one end toward the other and a band of paper forming a second outer wrap (18) unite the filter co-axially of the tobacco column. The outer wraps are substantially non-porous and of an axial length relative to the length of the filter whereby the surface area of exposed maintenance means is between about 25 mm2 and about 750 mm2. The maintenance means may be an inner wrap (22) of paper, with (Fig. 3) or without (Fig. 2) perforations, having a uniform porosity in the range of about 300 to 50,000 cc/min/cm2 at a pres-sure equivalent to 10 cm of water (Coresta units).

Description

l~885~4 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.

~ a~s~44 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 1 ~6854~

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 1 ~6854~

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 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 1 l~8~4~

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.

~ ~BS~4 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 1 ~685~l 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 ~6854~

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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Claims (14)

THE EMBODIMENTS OF THE INVENTION IN
WHICH AN EXCLUSIVE PROPERTY OR PRIVILEGE
IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A filter of rod-like form for a tobacco product or the like comprising a) filter means including a body of filter material having a first end adapted to enter the mouth of the user and a second end adapted to be disposed both juxtaposed to and coaxially with a column of tobacco, said filter means main-taining a substantially uniform level of porosity in the range of about 300 to 50,000 cc/min/cm2 at a pressure equivalent to 10 cm of water (Coresta units) thereby per-mitting ingress of ambient air into said body of filter material at a rate to provide dilution of mainstream smoke from about 50 to essentially 100% and a total tar delivery of less than about 9 mg, and b) a wrap of paper to surround said filter means, said wrap extending along said body of said filter means from said first end toward said second end, and said wrap being substantially non-porous thereby preventing said ingress of ambient air except as shall enter said body of said filter means throughout the region not surrounded by said outer wrap.

2. The filter of claim l wherein said body of filter material of said filter means is characterized by a non-wrapped cellulose acetate tow.

3. The filter of claim 1 wherein said body of filter material of said filter means is a cellulose acetate tow, and wherein said filter means further comprises a wrap providing said substantially uniform level of porosity intimately surrounding said filter material within said first-mentioned wrap.

4. The filter of claim 3 wherein said intimate wrap is characterized by an inner wrap of paper and includes a plurality of perforations located at least throughout the length of an exposed surface area and around said exposed surface area whereby ambient air enters said filter material through said perforations as well as through the adjacent porous, non-perforated area.

5. The filter of claim 4 wherein said perforations are located at equidistant circumferential spacing in at least one ring about said inner wrap.

6. The filter of claim 5 wherein the total area of said perforations is between about 0.1 mm2 to about 100 mm2.

7. The filter of any one of claims 1, 2 or 3 wherein said filter means is of a length of about 20 to 50 mm and wherein said first-mentioned wrap characterized by an outer wrap extends from said first end of said filter means throughout a length of about 10 mm to about 20 mm toward said second end.

8. A tobacco product or the like comprising a) a tobacco column, b) a wrap for said tobacco column, c) a filter means for filtering mainstream smoke from said tobacco column, said filter means comprising (1) a body of filter material of rod-like form having a first end adapted to be placed in the mouth of the user and a second end adapted to be located juxta-posed to and coaxially with said tobacco column, said filter means maintaining a substantially uniform level of porosity in the range of about 300 to 50,000 cc/
min/cm2 at a pressure equivalent to 10 cm of water (Coresta units) thereby permit-ting an ingress of ambient air into said body of filter material so as to dilute the mainstream smoke from about 50 to essentially 100% and a total tar delivery of less than about 9 mg, and (2) a wrap of paper to surround said filter means, said wrap extending along said body of said filter means from said first end toward said second end, and said wrap being substantially non-porous thereby preventing said ingress of ambient air except as shall enter said body of said filter means throughout the region not surrounded by said outer wrap, and d) a band of paper forming a second wrap for connecting said filter means and said tobacco column, said band of paper being non-porous and together with said wrap limiting said surface area of exposed filter means to between about 25 mm2 and about 750 mm2.

9. The tobacco product of claim 8 wherein said body of said filter means is characterized by a non-wrapped cellulose acetate tow.

10. The tobacco product of claim 8 wherein said body of filter material is a cellulose acetate tow, and wherein said filter means further comprises a wrap providing said substantially uniform level of porosity intimately surrounding said filter material within said first-mentioned wrap.

11. The tobacco product of claim 10 wherein said intimate wrap is characterized by an inner wrap of paper and includes a plurality of perforations located at least throughout the length of and around said exposed surface area whereby ambient air enters said filter material through said perforations as well as through the adjacent porous, non-perforated area.

12. The tobacco product of claim 11 wherein said perforations are located at equidistant circumferential spacing in at least one ring about said inner wrap.

13. The tobacco product of claim 12 wherein the total area of said perforations is between about 0.1 mm2 and about 100 mm2 whereby about 25 to about 100 percent of said ambient air enters said filter material through said perforations.

14. The tobacco product of any one of claims 8, 9 or 10 wherein said filter means is of a length of about 20 to 50 mm and said first mentioned wrap characterized by an outer wrap extends from said first end of said filter means throughout a length toward said second end to provide a space permitting at least about 80%
dilution and tar delivery of less than 2 mg.