CA1212008A - Smoke filter having extended film overwrap and method and apparatus for fabricating same - Google Patents
Smoke filter having extended film overwrap and method and apparatus for fabricating sameInfo
- Publication number
- CA1212008A CA1212008A CA000417850A CA417850A CA1212008A CA 1212008 A CA1212008 A CA 1212008A CA 000417850 A CA000417850 A CA 000417850A CA 417850 A CA417850 A CA 417850A CA 1212008 A CA1212008 A CA 1212008A
- Authority
- CA
- Canada
- Prior art keywords
- rod
- filter
- smoke
- film
- overwrap
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
- A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
- A24D3/02—Manufacture of tobacco smoke filters
- A24D3/0229—Filter rod forming processes
- A24D3/0237—Filter rod forming processes by extrusion
-
- A—HUMAN NECESSITIES
- A24—TOBACCO; CIGARS; CIGARETTES; SIMULATED SMOKING DEVICES; SMOKERS' REQUISITES
- A24D—CIGARS; CIGARETTES; TOBACCO SMOKE FILTERS; MOUTHPIECES FOR CIGARS OR CIGARETTES; MANUFACTURE OF TOBACCO SMOKE FILTERS OR MOUTHPIECES
- A24D3/00—Tobacco smoke filters, e.g. filter-tips, filtering inserts; Filters specially adapted for simulated smoking devices; Mouthpieces for cigars or cigarettes
- A24D3/04—Tobacco smoke filters characterised by their shape or structure
- A24D3/043—Tobacco smoke filters characterised by their shape or structure with ventilation means, e.g. air dilution
Landscapes
- Cigarettes, Filters, And Manufacturing Of Filters (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A tobacco smoke filter includes a smoke pervious rod of plastic material about which a smoke impervious plastic overwrap film is extruded. The the overwrap and the rod are made of the same material, i.e., cellulose acetate. By using the same material, waste from the normal filter-making processes can be formed into granules or pellets and rendered molten for re-cycling as the raw material for the overwrap film. The resulting filter can be used with or without a tipping paper cover and can be per-forated or not, as desired, to ventilate the filter rod.
A tobacco smoke filter includes a smoke pervious rod of plastic material about which a smoke impervious plastic overwrap film is extruded. The the overwrap and the rod are made of the same material, i.e., cellulose acetate. By using the same material, waste from the normal filter-making processes can be formed into granules or pellets and rendered molten for re-cycling as the raw material for the overwrap film. The resulting filter can be used with or without a tipping paper cover and can be per-forated or not, as desired, to ventilate the filter rod.
Description
~2~U8 BACKGROUND OF TOE NVENTION
Technical Field The present invention relates to filter elements and the rnethod arld apparatus or fabricating such filter elernents. More particul.lrly, the present inven-tion relates to an improved overwrap for a tobacco smoke fi]ter which considerably reduces filter fabri-cation costs without introducing undesirable side effects.
Although the present invention is primarily concerned with producing filter means for cigarettes, it should be noted that the products of the present invention are generally useful as filters for any tobacco smoking means, whether tlley be cigarettes, cigars, pipes, etc. Since filters for cigarettes have particular commercial importance, the preferred embodiments described herein relate to the production of filtered cigarettes.
The Prior Art In fabricating filters for use in connection with cigarettes and the like, a number of different proper ties of the resultant filter must be taken into consideratioll. Wilile lil~rati(~rl t~lllcierlcy l lit ability of the filter to remove undesirable consti-tuents frorn the tobacco smoke) is a very important property of cigarette filters, filtration erIIiciency must frequently be cornpromised in order for the filter to possess a commercially acceptable corrbination of other properties, including pressure drop, taste, hardness, appearance and cost. For example, the most commonly utilized cigarette filter material cellulose ox acetate, has a relatively low filtration efficiency;
however, this material has a commercially acceptable overall combination of properties.
The relatively poor filtration efficiency of cellulose acetate has resulted in a long but unsuccess-ful search for an acceptable substitute. A wide v<lrlety ox` ~iff`erc~rl~ m;lterl~l; tJIV(~ by rl fit Irlclll-ding paper, polypropylene, and others, but all have been rejected primarily because they introduce an unacceptable taste to the smoker. It has been found that the taste of cigarette smoke is extremely sensi-tive to the filter material and to foreign substances in or in contact with the filter material. Even in cases where filters have been modified with plastic tubes or other ingredients, the resulting taste has proven to be commercially objectionable.
In spite of the objectionable taste introduced into smoke by paper, it is the most economical and commercially viable rnaterial for plug wrap or overwrap material used to circumscribe a cellulose acetate filter rod. The use of paper overwrap is clearly a cornpro-mise of the filter taste property. In order to avoid this compromise in taste, attempts have been made to change the filter structure, the filter material, and the overwrap material; all have been commercii-llly ate the overwrap entirely; however, these have been unsuccessful because, without an overwrap, the fabri-cation machines cannot be operated at high speeds.
The present invention provides a smoke filter with an overwrap which does no-t introduce unpleasant taste to the filtered smoke The present invention also provides a smoke filter with an overwrap which can be applied inexpensively and with-out introducing undesirable properties for the final filter product.
The present invention further provides a smoke filter overwrap material which permits production rates to be increased.
The present invention again provides a method and apparatus for fabricating a smoke filter with an overwrap material which achieves the objects and advantages des-cribed above.
In accordance with the present invention, a plug wrap or overwrap for a smoke filter rod ta]ces the form of a smoke-impervious plastic cellulose acetate film extruded about the rod. The resulting overwrapped filter can be used with or without tipping paper; if tipping is used, the taste of the smoke is unaffected because the smoke-impervious film eliminates contact between the paper andthe smoke. The film is made from the same ma-terial as the filter i.e. cellulose acetate, so as to avoid introducing taste variations. Utilizing the same material in the filter rod and overwrap also has the advantage of permitting re-cycling of the waste filter material for use as the overwrapfilm. Plasticizers of the type which are conventionally used in filter rods to bond fibers to one another serve to completely adhere the bonded fibers to the film, thereby eliminating the need for adhesvie to hold the }8 fibers to -the overwrap. Elimination of this adhesive material reduces the cost and removes another foreign material that can adversely affect taste.
The resulting filter has the advantages of:
isolating the filter material from taste-contaminating foreign matter; cost saving of ma..,erial as compared to paper overwrap; and a hi.gher production rate.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodi-ments thereof, especially when taken in conjunc-tion with the accompanying drawings, wherein:-Figure 1 is a view in perspective of one form of cigarette produced in accordance with the present invention, the tipping paper being partially torn away for illustrative clarity;
Figure 2 is a view in section through the filter rod of Figure l taken along lines 2-2 of Figure l;
Figure 3 is a view in perspective of another filter in accordance with the present invention with the tipping paper once again being partially torn away for illustrative clarity;
Figure 4 is a view in section of a filter rod constructed in accordance with the present inven-tion wherein ventilation holes are provided in the tipping paper and filter overwrap;
i2~ 8 Figure 5 is a schematic illustration of' a method and apparatus for fabricating filter elements in accordance with the present invention; and Figure 6 is a partially schematic view in section of an extrusion apparatus for applying plug wrap to the filter rod in the method and apparatus illustrated in Figure 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referrine to the drawings with greater specifi-city and, particularly to Figures 1 and 2, a filtered cigarette according to the present invention is generally designated by the reference numeral 10.
Cigarette 10 includes a tobacco rod 12 and a filter element 14 constructed in accordance with one embodi-ment of the present invention. A ring of tippingpaper 16 joins the tobacco rod 12 and filter element 14 in axially aligned end-to-end abutment. The tipping paper 16 has a relatively short axial length and extends only a short axial distance along the tobacco rod 12 and the filter element 14. The whole purpose for the tipping paper 16 is to join the tobacco rod 12 and fi]ter element 14; other means of joining these two members may be employed.
The filter element 14 is a generally cylindrical plug of conventional tobacco smoke filter material and is typically made from continuous tow of cellulose acetate filamentary material.
3o Cellulose acetate filamentary tow is the preferred material from a commercial standpoint. In this sense, filter plug 14 is fabricated from conventional material to function as a smoke-pervious filter plug for trapping solid particulates in the smoke passing therethrough. Filter plug or rod 14 is circumscribed along its entire length by a smoke-impervious or non-porous plug wrap or overwrap 18. the unique aspect of the filter of the present invention resides in the fact that the overwrap 18 is extruded about the filter plug 14 in the form of a film. The filter material is cellulose acetate filamentary tow, and the extruded film is made of cellulose acetate.
It is important to note that the overwrap film 18 is strictly that, namely, an overwrap. It should not be confused with prior art attempts to extrude entire filter structures, which attemptshave proven largely unacceptable from a commercial point of view. Thus, whereas the filter rod 14 has a diameter on the order of 0.25 inches, the -thick-ness of the overwrap film l is on the order of 0.25 milsto 2.5 mils and is therefore between 100 and 1,000 times less than the filter rod diameter.
By using an extruded film overwrap having the same material as the filter rod itself, the chance of any foreign ingredients coming into contact with the smoke is virtually nil. Moreover, by introducing conventional plasticizers such as triacetin or any other conventional plasticizer used in cigarette filters, complete adherence of the bonded fibers to the film is assured. This eliminates the need for a sep-~2~2-- 8 --arate adhesive material which is required to hold paper overwrap to a filter rod. This not only reduces the cost of the adhesive material but also eliminates another bond oE material which could contact and contaminate the taste of the smoke.
A considerable material cost saving is provided when the film overwrap is made from the same material as is employed for making the filter rod. Specifically, using the same material permits re-cycling of the waste from the normal filter--making process. As the filter material is cellulose acetate, all of the waste in making the filter rod is conventional acetate without paper overwrap. This cellulose acetate waste can be formed into granules or pellets and extruded as the overwrap film. This re-cycling is not possible if there is paper contamination in the cellulose acetate waste because molding-grade resin can not be achieved with paper contamination present.
The use of the tipping paper 16, as illustrated in Figure 1, may be dispensed with if another technique for bonding the filter rod 14 to the tobacco rod 12 is employed. In either case, the portion of the cigarette which contacts the lips of the smoker is the overwrap material 18 which is smooth and does not stick to the smoker's lips as does paper coating. In addition, the overall surface character of the filter is commerci-ally advantageous with respect to paper overwrap. It should also be noted that the thin film provides structural strength so as to permit high speed filter fabrication operation. oven a very thin film overwrap is sufficient to compress an oversized rod and provide the structural strength necessary for both high speed production and desirable smoking characteristics.
~Z [)~8 Although -the cigarette illustrated in Figures 1 and
Technical Field The present invention relates to filter elements and the rnethod arld apparatus or fabricating such filter elernents. More particul.lrly, the present inven-tion relates to an improved overwrap for a tobacco smoke fi]ter which considerably reduces filter fabri-cation costs without introducing undesirable side effects.
Although the present invention is primarily concerned with producing filter means for cigarettes, it should be noted that the products of the present invention are generally useful as filters for any tobacco smoking means, whether tlley be cigarettes, cigars, pipes, etc. Since filters for cigarettes have particular commercial importance, the preferred embodiments described herein relate to the production of filtered cigarettes.
The Prior Art In fabricating filters for use in connection with cigarettes and the like, a number of different proper ties of the resultant filter must be taken into consideratioll. Wilile lil~rati(~rl t~lllcierlcy l lit ability of the filter to remove undesirable consti-tuents frorn the tobacco smoke) is a very important property of cigarette filters, filtration erIIiciency must frequently be cornpromised in order for the filter to possess a commercially acceptable corrbination of other properties, including pressure drop, taste, hardness, appearance and cost. For example, the most commonly utilized cigarette filter material cellulose ox acetate, has a relatively low filtration efficiency;
however, this material has a commercially acceptable overall combination of properties.
The relatively poor filtration efficiency of cellulose acetate has resulted in a long but unsuccess-ful search for an acceptable substitute. A wide v<lrlety ox` ~iff`erc~rl~ m;lterl~l; tJIV(~ by rl fit Irlclll-ding paper, polypropylene, and others, but all have been rejected primarily because they introduce an unacceptable taste to the smoker. It has been found that the taste of cigarette smoke is extremely sensi-tive to the filter material and to foreign substances in or in contact with the filter material. Even in cases where filters have been modified with plastic tubes or other ingredients, the resulting taste has proven to be commercially objectionable.
In spite of the objectionable taste introduced into smoke by paper, it is the most economical and commercially viable rnaterial for plug wrap or overwrap material used to circumscribe a cellulose acetate filter rod. The use of paper overwrap is clearly a cornpro-mise of the filter taste property. In order to avoid this compromise in taste, attempts have been made to change the filter structure, the filter material, and the overwrap material; all have been commercii-llly ate the overwrap entirely; however, these have been unsuccessful because, without an overwrap, the fabri-cation machines cannot be operated at high speeds.
The present invention provides a smoke filter with an overwrap which does no-t introduce unpleasant taste to the filtered smoke The present invention also provides a smoke filter with an overwrap which can be applied inexpensively and with-out introducing undesirable properties for the final filter product.
The present invention further provides a smoke filter overwrap material which permits production rates to be increased.
The present invention again provides a method and apparatus for fabricating a smoke filter with an overwrap material which achieves the objects and advantages des-cribed above.
In accordance with the present invention, a plug wrap or overwrap for a smoke filter rod ta]ces the form of a smoke-impervious plastic cellulose acetate film extruded about the rod. The resulting overwrapped filter can be used with or without tipping paper; if tipping is used, the taste of the smoke is unaffected because the smoke-impervious film eliminates contact between the paper andthe smoke. The film is made from the same ma-terial as the filter i.e. cellulose acetate, so as to avoid introducing taste variations. Utilizing the same material in the filter rod and overwrap also has the advantage of permitting re-cycling of the waste filter material for use as the overwrapfilm. Plasticizers of the type which are conventionally used in filter rods to bond fibers to one another serve to completely adhere the bonded fibers to the film, thereby eliminating the need for adhesvie to hold the }8 fibers to -the overwrap. Elimination of this adhesive material reduces the cost and removes another foreign material that can adversely affect taste.
The resulting filter has the advantages of:
isolating the filter material from taste-contaminating foreign matter; cost saving of ma..,erial as compared to paper overwrap; and a hi.gher production rate.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodi-ments thereof, especially when taken in conjunc-tion with the accompanying drawings, wherein:-Figure 1 is a view in perspective of one form of cigarette produced in accordance with the present invention, the tipping paper being partially torn away for illustrative clarity;
Figure 2 is a view in section through the filter rod of Figure l taken along lines 2-2 of Figure l;
Figure 3 is a view in perspective of another filter in accordance with the present invention with the tipping paper once again being partially torn away for illustrative clarity;
Figure 4 is a view in section of a filter rod constructed in accordance with the present inven-tion wherein ventilation holes are provided in the tipping paper and filter overwrap;
i2~ 8 Figure 5 is a schematic illustration of' a method and apparatus for fabricating filter elements in accordance with the present invention; and Figure 6 is a partially schematic view in section of an extrusion apparatus for applying plug wrap to the filter rod in the method and apparatus illustrated in Figure 5.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referrine to the drawings with greater specifi-city and, particularly to Figures 1 and 2, a filtered cigarette according to the present invention is generally designated by the reference numeral 10.
Cigarette 10 includes a tobacco rod 12 and a filter element 14 constructed in accordance with one embodi-ment of the present invention. A ring of tippingpaper 16 joins the tobacco rod 12 and filter element 14 in axially aligned end-to-end abutment. The tipping paper 16 has a relatively short axial length and extends only a short axial distance along the tobacco rod 12 and the filter element 14. The whole purpose for the tipping paper 16 is to join the tobacco rod 12 and fi]ter element 14; other means of joining these two members may be employed.
The filter element 14 is a generally cylindrical plug of conventional tobacco smoke filter material and is typically made from continuous tow of cellulose acetate filamentary material.
3o Cellulose acetate filamentary tow is the preferred material from a commercial standpoint. In this sense, filter plug 14 is fabricated from conventional material to function as a smoke-pervious filter plug for trapping solid particulates in the smoke passing therethrough. Filter plug or rod 14 is circumscribed along its entire length by a smoke-impervious or non-porous plug wrap or overwrap 18. the unique aspect of the filter of the present invention resides in the fact that the overwrap 18 is extruded about the filter plug 14 in the form of a film. The filter material is cellulose acetate filamentary tow, and the extruded film is made of cellulose acetate.
It is important to note that the overwrap film 18 is strictly that, namely, an overwrap. It should not be confused with prior art attempts to extrude entire filter structures, which attemptshave proven largely unacceptable from a commercial point of view. Thus, whereas the filter rod 14 has a diameter on the order of 0.25 inches, the -thick-ness of the overwrap film l is on the order of 0.25 milsto 2.5 mils and is therefore between 100 and 1,000 times less than the filter rod diameter.
By using an extruded film overwrap having the same material as the filter rod itself, the chance of any foreign ingredients coming into contact with the smoke is virtually nil. Moreover, by introducing conventional plasticizers such as triacetin or any other conventional plasticizer used in cigarette filters, complete adherence of the bonded fibers to the film is assured. This eliminates the need for a sep-~2~2-- 8 --arate adhesive material which is required to hold paper overwrap to a filter rod. This not only reduces the cost of the adhesive material but also eliminates another bond oE material which could contact and contaminate the taste of the smoke.
A considerable material cost saving is provided when the film overwrap is made from the same material as is employed for making the filter rod. Specifically, using the same material permits re-cycling of the waste from the normal filter--making process. As the filter material is cellulose acetate, all of the waste in making the filter rod is conventional acetate without paper overwrap. This cellulose acetate waste can be formed into granules or pellets and extruded as the overwrap film. This re-cycling is not possible if there is paper contamination in the cellulose acetate waste because molding-grade resin can not be achieved with paper contamination present.
The use of the tipping paper 16, as illustrated in Figure 1, may be dispensed with if another technique for bonding the filter rod 14 to the tobacco rod 12 is employed. In either case, the portion of the cigarette which contacts the lips of the smoker is the overwrap material 18 which is smooth and does not stick to the smoker's lips as does paper coating. In addition, the overall surface character of the filter is commerci-ally advantageous with respect to paper overwrap. It should also be noted that the thin film provides structural strength so as to permit high speed filter fabrication operation. oven a very thin film overwrap is sufficient to compress an oversized rod and provide the structural strength necessary for both high speed production and desirable smoking characteristics.
~Z [)~8 Although -the cigarette illustrated in Figures 1 and
2 has no provision for air ventilation of the filter, it is clear that holes may be provided in the overwrap film 18 in order to provide ventilation cornmunication between the filter rod 14 and ambient air.
The cigarette fil-ter embodiment illustrated in Figure 3 shows a tipping paper overwrap 20 circumscribed about the entire length of the extruded overwrap film 18, as well as a portion of the tobacco rod 12. In all other respects, the filter arrangement of Figure 3 is idenlical to that illustrated and described in Figure 1. It is possible, of course, to deform the filter rod of Figure 3 in the manner described in my copending Canadian Patent Application Serial No. 400,646 filed April 7, 1982, in which case the tipping paper 20, suitably provided with ventilation holes, defines a ventilation passage with the deformed portion of the fil-ter rod. The result is air dilution of the smoke, a fea-ture which has gained some popularity in the tobacco industry in recent years.
Referring to Figure 4 specifically of the accom-panying drawings, a filter rod such as tnat illustrated in Figure 3, is shown in section and is provided with a plurality of ventilation holes extending through the paper tipping 20 and the film overwrap l As noted above, the tipping paper 20 can be eliminated and the holes can extend through the overwrap film 18 alone. The holes serve to admit air into the smoke as the smoker draws on the exposed end of tne filter rod, thereby providing a degree of air dilu-tion determined by the number and size of the apertures. The overwrap film can be perforated at the same time that -the tipping paper 20 is perforated by any techniques well known in the prior art for this purpose. however, the most uniform perforation method is with lasers.
g A method and apparatus for fabricating the filter elements of the presen-t invention is illustrated in Figure 5, -to which specific reference is now made. Basically, the fabrication technique is similar in many respec-ts to the techniques described and illustrated in U.S. Patents Nos. 3,637,447; 4,046l063; 4,075,936; and Canadian Patent application Nos. 388,949 filed October 28, 1981 and 400,646 filed April 7, ].982~ The filtering material utilized in the production of filter elements is a continuous filamen--tary tow designated generally by the reference numeral 40.
This filamentary tow 40 includes a multiplicity of bondable fibrous members activated by contact with a hot fluid such as steam. Filtering material 40 is continuously passed into and throuqh an elongated bonding zone which includes a con-ventional stuffer jet 41 and steam head 42, similar innature to those illustrated and described in the various above-mentioned patents and patent applications. Following the steam treatment, the resulting rod is cooled at cooling head 43 before being passed through a pulling device 51.
Upon leaving the pulling device, the unwrapped rod is passed to a vacuum chamber 82 after which the rod is passed to an extruder and tube dye 83, the latter being described in greater detail below with reference to F.igure 6.
In the extruder and tube dye 83, a film of plastic material is extruded over the filter rod so as to conform to the exact shape of the rod. Any suitable smoke-impervious p].asti.c film may be utilized for this purpose and, in the preferred embodiment, is cellulose acetate. The wrapped rod then passes through a water bath 84 to a pulling device 85 before being cut into individual filter plugs at cutter head 86.
Referring specifically to Figure 6 of the accompanying drawi.ngs, the vacuu7n chamber 82 is illustrated with the unwrapped rod 87 passing through a bore 88 extending longitudinally therethrough. The inlet end 89 of bore 88 is flared to provide a flow outlet which expands in the direction opposite the somewhat larger in diameter tnan the diameter of rod 87 sO that air can flow in an annular path through bore 88 in opposition to rod movement. In order to withdraw air from bore 88, an anrlular nozz1.e ls provided at the point where bore 88 begins to f],are 'in portion 89. The annular nozzle is fed by air under pressure which aspirates air from the bore 88 and out through the flared outlet 89. As a conse-quence, an extremely lo pressure is provided in bore 88. A portion of the vacuum chamber 82 extends into the extruder and tube dye member 83 such that bore 88 communicates coaxially with a similarly provided bore 90 in the tube dye and extruder member 83. Rod 87 passes through bore 90 which is aspirated by the annular nozzle 9l in the same manner as bore 88.
Plastic is fed into the tube dye and extruder member 83 by a nozzle 92 which feeds the plastic in its mol.ten form to an annular nozzle 94 disposed concentrica1ly about, the outlet, of bore sn. The 1OW
pressure region forllled arourld rod 8'~ in bore 90 causes the annular flow of plastic filln from the nozzle 94 to surround and conform to the rod as the rod egresses 3o from the tube dye and extruder member 83. This plastic film 95 constitutes the plug wrap 18 described above in relation to the embodiment illustrated in Figures 1-4.
The method described in relation to Figures 5 and 6, whereby the vacuum draws the pla.stic film to the exact shape of the filter rod and permits the smoke-imper-meable film to conform to the deformecl rod, is considerably cheaper than the conventional plug wrap approach wherein paper is used as the plug wrap. The film 95 is generally extruded to a thickness between 0.25 mils and 2.5 mils, the thickness being controlled by varying the speed ratio bet-ween the formed rod and the extruder film.
As noted above, when the filter material 40 and the film 95 are -the same, any waste material which is formed during the normal manufacturing process can be re-cycled as the extruded overwrap film 95.
Although the filter rod formed as part of the pro-cess illustrated in Figures 5 and 6 is cylindrical thecylindrical periphery can be deformed in the manner des-cribed in my U.S. Patent No. 4,423,744 in order to achieve air dilution characteristics for the filter.
The apparatus for forming the filter according to the present invention runs more efficiently than do prior art filter fabricating machines because there is no require-ment to slow down or stop to change the plug wrap. In fact, with tow splicing equipment incorporated, the machines are capable of running at 100~ efficiency around the clock.
Another advantage to using cellulose acetate film as an overwrap for the cellulose acetate tow material is that it may be formulated with a plasticizer to produce a flexible film which prevents formation of air pockets associa-ted with tipping in the paper-wrapped filters. These pockets are caused by the differential in size between the filter and the cigarette. Since paper does not conform, it wrinkles and causes these \
air pockets to form. The thin film-wrapped fitters of the present invention, however, do not require the close circumferential tolerance required by paper-wrapped fllters. Using -the present invention, I have found that cellulose acetate filter rods of 100 milli-meter length can be wrapped at a material cost of 6¢ per thousand rods. The least expensive paper wrap has a material cost of 15¢ per thousand rods and some-times varies as high as 30¢ per thousand rods, without even considering the cost of glue and other additives emp]oyed in conjunction with the paper wrap to produce a satisfactory filter.
3o
The cigarette fil-ter embodiment illustrated in Figure 3 shows a tipping paper overwrap 20 circumscribed about the entire length of the extruded overwrap film 18, as well as a portion of the tobacco rod 12. In all other respects, the filter arrangement of Figure 3 is idenlical to that illustrated and described in Figure 1. It is possible, of course, to deform the filter rod of Figure 3 in the manner described in my copending Canadian Patent Application Serial No. 400,646 filed April 7, 1982, in which case the tipping paper 20, suitably provided with ventilation holes, defines a ventilation passage with the deformed portion of the fil-ter rod. The result is air dilution of the smoke, a fea-ture which has gained some popularity in the tobacco industry in recent years.
Referring to Figure 4 specifically of the accom-panying drawings, a filter rod such as tnat illustrated in Figure 3, is shown in section and is provided with a plurality of ventilation holes extending through the paper tipping 20 and the film overwrap l As noted above, the tipping paper 20 can be eliminated and the holes can extend through the overwrap film 18 alone. The holes serve to admit air into the smoke as the smoker draws on the exposed end of tne filter rod, thereby providing a degree of air dilu-tion determined by the number and size of the apertures. The overwrap film can be perforated at the same time that -the tipping paper 20 is perforated by any techniques well known in the prior art for this purpose. however, the most uniform perforation method is with lasers.
g A method and apparatus for fabricating the filter elements of the presen-t invention is illustrated in Figure 5, -to which specific reference is now made. Basically, the fabrication technique is similar in many respec-ts to the techniques described and illustrated in U.S. Patents Nos. 3,637,447; 4,046l063; 4,075,936; and Canadian Patent application Nos. 388,949 filed October 28, 1981 and 400,646 filed April 7, ].982~ The filtering material utilized in the production of filter elements is a continuous filamen--tary tow designated generally by the reference numeral 40.
This filamentary tow 40 includes a multiplicity of bondable fibrous members activated by contact with a hot fluid such as steam. Filtering material 40 is continuously passed into and throuqh an elongated bonding zone which includes a con-ventional stuffer jet 41 and steam head 42, similar innature to those illustrated and described in the various above-mentioned patents and patent applications. Following the steam treatment, the resulting rod is cooled at cooling head 43 before being passed through a pulling device 51.
Upon leaving the pulling device, the unwrapped rod is passed to a vacuum chamber 82 after which the rod is passed to an extruder and tube dye 83, the latter being described in greater detail below with reference to F.igure 6.
In the extruder and tube dye 83, a film of plastic material is extruded over the filter rod so as to conform to the exact shape of the rod. Any suitable smoke-impervious p].asti.c film may be utilized for this purpose and, in the preferred embodiment, is cellulose acetate. The wrapped rod then passes through a water bath 84 to a pulling device 85 before being cut into individual filter plugs at cutter head 86.
Referring specifically to Figure 6 of the accompanying drawi.ngs, the vacuu7n chamber 82 is illustrated with the unwrapped rod 87 passing through a bore 88 extending longitudinally therethrough. The inlet end 89 of bore 88 is flared to provide a flow outlet which expands in the direction opposite the somewhat larger in diameter tnan the diameter of rod 87 sO that air can flow in an annular path through bore 88 in opposition to rod movement. In order to withdraw air from bore 88, an anrlular nozz1.e ls provided at the point where bore 88 begins to f],are 'in portion 89. The annular nozzle is fed by air under pressure which aspirates air from the bore 88 and out through the flared outlet 89. As a conse-quence, an extremely lo pressure is provided in bore 88. A portion of the vacuum chamber 82 extends into the extruder and tube dye member 83 such that bore 88 communicates coaxially with a similarly provided bore 90 in the tube dye and extruder member 83. Rod 87 passes through bore 90 which is aspirated by the annular nozzle 9l in the same manner as bore 88.
Plastic is fed into the tube dye and extruder member 83 by a nozzle 92 which feeds the plastic in its mol.ten form to an annular nozzle 94 disposed concentrica1ly about, the outlet, of bore sn. The 1OW
pressure region forllled arourld rod 8'~ in bore 90 causes the annular flow of plastic filln from the nozzle 94 to surround and conform to the rod as the rod egresses 3o from the tube dye and extruder member 83. This plastic film 95 constitutes the plug wrap 18 described above in relation to the embodiment illustrated in Figures 1-4.
The method described in relation to Figures 5 and 6, whereby the vacuum draws the pla.stic film to the exact shape of the filter rod and permits the smoke-imper-meable film to conform to the deformecl rod, is considerably cheaper than the conventional plug wrap approach wherein paper is used as the plug wrap. The film 95 is generally extruded to a thickness between 0.25 mils and 2.5 mils, the thickness being controlled by varying the speed ratio bet-ween the formed rod and the extruder film.
As noted above, when the filter material 40 and the film 95 are -the same, any waste material which is formed during the normal manufacturing process can be re-cycled as the extruded overwrap film 95.
Although the filter rod formed as part of the pro-cess illustrated in Figures 5 and 6 is cylindrical thecylindrical periphery can be deformed in the manner des-cribed in my U.S. Patent No. 4,423,744 in order to achieve air dilution characteristics for the filter.
The apparatus for forming the filter according to the present invention runs more efficiently than do prior art filter fabricating machines because there is no require-ment to slow down or stop to change the plug wrap. In fact, with tow splicing equipment incorporated, the machines are capable of running at 100~ efficiency around the clock.
Another advantage to using cellulose acetate film as an overwrap for the cellulose acetate tow material is that it may be formulated with a plasticizer to produce a flexible film which prevents formation of air pockets associa-ted with tipping in the paper-wrapped filters. These pockets are caused by the differential in size between the filter and the cigarette. Since paper does not conform, it wrinkles and causes these \
air pockets to form. The thin film-wrapped fitters of the present invention, however, do not require the close circumferential tolerance required by paper-wrapped fllters. Using -the present invention, I have found that cellulose acetate filter rods of 100 milli-meter length can be wrapped at a material cost of 6¢ per thousand rods. The least expensive paper wrap has a material cost of 15¢ per thousand rods and some-times varies as high as 30¢ per thousand rods, without even considering the cost of glue and other additives emp]oyed in conjunction with the paper wrap to produce a satisfactory filter.
3o
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A smoke filter comprising a smoke pervious plastic filter rod of filamentary cellulose acetate material extending longitudinally between a smoke receiving end and a smoke discharging end, said filter rod having at least one transverse dimension of predetermined length; and a smoke impervious overwrap in the form of a discrete film extrudate of non-filamentary cellulose acetate material circumfer-entially surrounding the entire periphery of said filter rod between said smoke receiving end and said smoke discharging end, said film extrudate having a thickness which is at least 100 times smaller than said predetermined length.
2. The smoke filter according to claim 1, wherein said filter rod is a cigarette filter rod and includes a generally cylindrical portion, wherein said at least one transverse dimention is the diameter of said cylindrical portion, and wherein said thickness of said film is less than 2.5 mils.
3. The smoke filter according to claim 2, wherein said thickness of said film is less than 1.0 mil.
4. The smoke filter according to claim 3, wherein the thickness of said film is approximately 0.25 mils.
5. The smoke filter according to claim 4, wherein said thickness of said film is less than 1.0 mil.
6. The smoke filter according to claim 5, wherein the thickness of said film is approximately 0.25 mils.
7. The smoke filter according to claim 1, wherein at least one groove is defined in said filter rod and in said overwrap, said groove having a depth dimension extend-ing radially inward of said rod and a length dimension which extends a predetermined distance along said rod, said groove being open to ambient air along its entire length.
8. The smoke filter according to claim 1, wherein said overwrap and said rod have a transverse cross-sectional perimeter which is smaller along one longitudinal portion of said rod than the remainder of said rod, said filter further comprising tipping means having a perimeter which is sub-stantially constant throughout the entire length of said rod, said tipping means including ventilation holes defined therein at a location along the smaller perimeter portion of said rod for permitting air to flow into and through space defined between said tipping means and said rod.
9. The smoke filter according to claim 1, further comprising a plurality of radially-extending holes defined through said plastic film to provide ventilation between the filter rod and ambient air.
10. A filtered cigarette comprising in combination a tobacco rod and a smoke filter as defined in claim 1 secured in end-to-end relationship.
11. The smoke filter according to claim 1, wherein said plastic film includes a plasticizer for producing a flexible film and facilitating bonding between the film and the filter rod.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US333,802 | 1981-12-23 | ||
| US06/333,815 US4499912A (en) | 1981-12-23 | 1981-12-23 | Free air dilution smoke filter and method and apparatus for fabricating same |
| US333,815 | 1981-12-23 | ||
| US06/333,802 US4423744A (en) | 1981-12-23 | 1981-12-23 | Tobacco smoke filter contoured to provide undiluted air flow and method and apparatus for manufacturing same |
| US444,056 | 1982-11-23 | ||
| US06/444,056 US4614199A (en) | 1981-12-23 | 1982-11-23 | Smoke filter having extended film overwrap and method and apparatus for fabricating same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1212008A true CA1212008A (en) | 1986-09-30 |
Family
ID=27406942
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000417850A Expired CA1212008A (en) | 1981-12-23 | 1982-12-16 | Smoke filter having extended film overwrap and method and apparatus for fabricating same |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0082734B1 (en) |
| CA (1) | CA1212008A (en) |
| DE (1) | DE3280328D1 (en) |
| GB (1) | GB2113068B (en) |
| HK (1) | HK86489A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10153821A1 (en) | 2001-11-05 | 2003-06-05 | Hauni Maschinenbau Ag | Multi-segment filter of the tobacco processing industry and method for producing the same |
| DE10153820A1 (en) * | 2001-11-05 | 2003-05-15 | Hauni Maschinenbau Ag | Filter segments or filters for cigarettes and processes for their manufacture |
| CN106263021B (en) * | 2016-11-01 | 2022-07-29 | 湖北中烟工业有限责任公司 | W-shaped cigarette filter stick forming device |
| RU2739544C1 (en) * | 2017-06-19 | 2020-12-25 | Джапан Тобакко Инк. | Smoking article filter and method of manufacturing thereof |
| EP3761814B1 (en) * | 2018-03-08 | 2025-12-17 | Philip Morris Products S.A. | Aerosol generating articles |
| WO2020222225A1 (en) * | 2019-05-01 | 2020-11-05 | Bello Ophir Ltd. | Smoking article mouthpiece |
| CN112895374B (en) * | 2021-02-07 | 2023-04-25 | 云南长宜科技有限公司 | Preparation method and device of airflow unit |
| CN112892948B (en) * | 2021-03-25 | 2025-01-14 | 红云红河烟草(集团)有限责任公司 | A quick-plug glue spray nozzle |
| CN114983017B (en) * | 2022-05-24 | 2023-08-22 | 云南中烟工业有限责任公司 | Inner core filled outer hollow filter stick and processing method thereof |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3789855A (en) * | 1971-06-22 | 1974-02-05 | Liggett & Myers Inc | High flavor impact, low smoke yield cigarette mouthpiece |
| CA999501A (en) * | 1972-08-21 | 1976-11-09 | George L. Mathe | Apparatus and method for producing filament tow filter rod having a foamed thermoplastic sheath |
| GB1414745A (en) * | 1973-02-26 | 1975-11-19 | Cigarette Components Ltd | Tobacco smoke filter |
| GB1585862A (en) * | 1976-11-19 | 1981-03-11 | British American Tobacco Co | Tobacco-smoke filters |
| AU4119078A (en) * | 1977-11-18 | 1980-05-08 | Philip Morris Inc | Filter system |
| US4256122A (en) * | 1979-04-11 | 1981-03-17 | Brown & Williamson Tobacco Corporation | Cigarette filter |
| US4387728A (en) * | 1981-03-19 | 1983-06-14 | Brown & Williamson Tobacco Corporation | Cigarette filter |
-
1982
- 1982-12-16 CA CA000417850A patent/CA1212008A/en not_active Expired
- 1982-12-23 DE DE8282306942T patent/DE3280328D1/en not_active Expired - Lifetime
- 1982-12-23 GB GB08236686A patent/GB2113068B/en not_active Expired
- 1982-12-23 EP EP82306942A patent/EP0082734B1/en not_active Expired
-
1989
- 1989-11-02 HK HK864/89A patent/HK86489A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| GB2113068A (en) | 1983-08-03 |
| EP0082734A2 (en) | 1983-06-29 |
| EP0082734B1 (en) | 1991-05-02 |
| DE3280328D1 (en) | 1991-06-06 |
| HK86489A (en) | 1989-11-10 |
| EP0082734A3 (en) | 1985-12-11 |
| GB2113068B (en) | 1985-11-27 |
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| MKEX | Expiry |