Cigarette having projections of an embossed plug wrap attached to a tipping paper

Information

  • Patent Grant
  • 6457475
  • Patent Number
    6,457,475
  • Date Filed
    Wednesday, May 9, 2001
    23 years ago
  • Date Issued
    Tuesday, October 1, 2002
    22 years ago
Abstract
A filter-tipped cigarette comprises a tobacco rod including a tobacco filler and a tobacco wrapper paper wrapped around the tobacco filler, a filter including a filter member and a filter wrapper paper integrally wrapped around the filter member, and a tip paper sheet having a plurality of apertures arranged along a circumferential direction and connecting the tobacco rod and the filter. The filter wrapper paper has an embossment on substantially an overall surface of the filter wrapper paper. The filter wrapper paper and the tip paper are adhered to each other selectively at projections of the embossment of the filter wrapper paper.
Description




This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 10-317867, filed Nov. 9, 1998, the entire contents of which are incorporated herein by reference.




BACKGROUND OF THE INVENTION




The present invention relates to a filter-tipped cigarette and more particularly to an improvement of a plug wrapper for providing cigarettes that exhibit a small variations in ratio of air flowing into a cigarette through a filter (filter ventilation ratio: hereinafter referred to as “Vf”).




A conventional filter-tipped cigarette is constituted by a tobacco rod and a filter that are connected by a so-called tip paper. The cigarette filter is formed by wrapping a wrapper paper around fibrous filter material, such as cellulose diacetate fibers, into a cylindrical shape. In recent years, in order to reduce the amount of a smoke component flowing into the mouth through a mouthpiece end of the filter, means is frequently used which causes air to flow in through the side surface of the filter, by combining a filter plug wrapper having an air permeability with a tip paper which is apertures by means of static electricity, a laser or the like. In such a filter with apertures, diluting air flows in through the peripheral portion of the filter into the mouth of a smoker while tobacco smoke is introduced through the central portion of the filter. Thus, the amount of the smoke component introduced into the mouth as a whole is reduced.




In the conventional cigarette described above, it has been confirmed that even where the filter plug wrapper and the tip paper are formed of the same material, large variations in the Vf value occurs. Since the Vf value is greatly correlated with the amount of the smoke component, these variations are not preferable.




Accordingly, an object of the present invention is to provide a filter-tipped cigarette that can suppress the variations of the Vf value and stably supply a reduced amount of a smoke component.




BRIEF SUMMARY OF THE INVENTION




The applicant has disclosed in Jpn. Pat. Appln. KOKAI Publication No. 6-90728 (corresponding to U.S. Pat. No. 5,464,028) that in a filter-tipped cigarette comprising a tobacco rod and a filter connected by a tip paper having air-permeating holes (ventilation apertures), the variations of Vf values correlate with adhesion between the filter wrapper paper and the tip paper, irrespective of the air permeability of the materials, such as the filter wrapper paper, which is wrapped around the filter member. To improve the filter wrapper paper, the adhesion has been alleviated by embossing the filter wrapper paper which is wrapped around the filter member, so that the variations of the Vf values can be reduced.




Based on the above findings, the present inventors made further studies to more stabilize the Vf values. As a result, they discovered that the Vf values can be more stabilized by adhering an embossed filter wrapper paper to a tip paper only at projected portions of the embossment, accomplishing the present invention.




Thus, according to the present invention, there is provided a filter-tipped cigarette comprising: a tobacco rod including a tobacco filler and a tobacco wrapper wrapped around the tobacco filler; a filter including a filter member and a filter wrapper paper integrally wrapped around the filter member; and a tip paper sheet having a pluraliy of apertures arranged along a circumferential direction and connecting the tobacco rod and the filter, the filter wrapper paper having an embossment on substantially an entire surface thereof, and the filter wrapper paper and the tip paper sheet being adhered to each other selectively at projections of the embossment of filter wrapper paper.




In the present invention, the filter wrapper paper and the tip paper can be adhered except for a region where the plurality of apertures are formed. Further, in the present invention, it. is preferable that the embossment have a depth of 10 to 100 μm, and the embossment have a pitch of 100 to 3000 μm.




Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.











BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING




The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.





FIG. 1

is a partially exploded perspective view showing a filter-tipped cigarette according to a first embodiment of the present invention;





FIG. 2

is a partially exploded perspective view showing a filter-tipped cigarette according to a second embodiment of the present invention;





FIG. 3A

is an enlarged plan view partially showing an exploded filter wrapper paper for use in the present invention;





FIG. 3B

is a cross-sectional view taken along the line IIIB—IIIB in

FIG. 3A

;





FIG. 4

is a schematic plan view of another exploded filter wrapper paper for use in the present invention;





FIG. 5

is a schematic plan view for explaining application of an adhesive to a tip paper for use in the present invention; and





FIG. 6

is an enlarged schematic cross-sectional view of a filter portion and a tip paper sheet of a filter-tipped cigarette of the present invention.











DETAILED DESCRIPTION OF THE INVENTION




The present invention will now be described in detail with reference to the drawings. The same or similar elements are identified by the same reference numerals throughout the drawings.





FIG. 1

is a partially exploded perspective view showing a filter-tipped cigarette according to a first embodiment of the present invention. The filter-tipped cigarette


10


shown in

FIG. 1

comprises a tobacco rod


11


and a filter


12


, and has a cylindrical shape as a whole, like the usual filter-tipped cigarette. The tobacco rod


11


and the filter


12


are connected by a tip paper


15


.




Like the usual cigarette, the tobacco rod


11


is formed of a tobacco filler


111


and a tobacco wrapper


112


wrapping the periphery of the filler. The tobacco rod may have a diameter of 5 to 10 mm and a length of 40 to 80 mm, for example.




The filter


12


is located at an end of the tobacco rod, and comprises a filter member


121


and a filter wrapper paper


122


wrapped around the filter member. The filter member


121


shown in

FIG. 1

has a single, so-called plane, filter structure. As in the usual filter-tipped cigarette, the filter member is constituted by a fibrous filter material such as cellulose acetate fibers. The diameter of the filter


12


is substantially the same as that of the tobacco rod


11


and its length may be, for example, 15 to 40 mm like the usual filter.




The filter wrapper paper


122


integrally wrapped around the filter member


121


preferably has a high air permeability of CORESTA permeability of 1000 or higher, and may be as thick as 10 to 100 μm. Substantially the overall surface of the filter wrapper paper


122


has an embossment


13


as will be described later in detail.




The tip paper sheet


15


covers the entire of the filter wrapper paper


122


and a portion of the tobacco wrapper


112


. The tip paper


15


may have a length in the axial direction of the cigarette (width) of 20 to 50 mm and a thickness of 10 to 100 μm. The tip paper


15


has a number of small apertures for air permeation (ventilation apertures)


16


arranged in one or a plurality of lines (two lines in

FIG. 1

) or irregularly along the circumferential direction of the cigarette. The apertures


16


of the tip paper


15


can be formed by conventional means, such as static electricity or a laser. The ventilation apertures


16


may be formed either before or after the tip paper


15


is adhered to the filter wrapper paper


122


.





FIG. 2

is a partially exploded perspective view showing a filter-tipped cigarette according to a second embodiment of the present invention. In

FIG. 2

, the elements corresponding to those shown in

FIG. 1

are identified by the same reference numerals as those used in

FIG. 1

, and explanations thereof will be omitted.




The filter-tipped cigarette shown in

FIG. 2

has a so-called dual filter structure, in which the filter member


121


is constituted by a first filter section


121




a


and a second filter section


121




b,


each made of fibrous filter material, such as cellulose acetate fibers. Each of the first filter section


121




a


and the second filter section


121




b


may have a length of, for example, 5 to 20 mm, and the sum of the lengths may be, for example, 15 to 40 mm. In the filter member


121


of the dual filter structure, the first filter section


121




a


may be a so-called charcoal filter in which activated carbon is dispersed therein.




The first and second filter sections


121




a


and


121




b


are individually wrapped sufficiently by a first individual filter wrapper paper


123




a


and a second individual filter wrapper paper


123




b


separate from each other (these individual wrapper may be collectively denoted by


123


hereinafter). It is preferable that each of the individual filter wrapper papers


123


have a permeability of 1000 CORESTA units or higher. The thickness of the filter wrapper papers


123


may be 10 to 100 μm. The first and second filter sections


121




a


and


123




b


wrapped by the individual filter wrapper papers


123




a


and


123




b


are collectively wrapped by a filter wrapper paper


122


having an embossment


13


as in the case of the cigarette shown in FIG.


1


.




Both in the filter-tipped cigarettes shown in

FIGS. 1 and 2

, the filter wrapper paper


122


integrally wrapped around the filter member


121


has the embossment


13


preferably having a lattice concave (groove) pattern.





FIGS. 3A and 3B

are diagrams showing a part of an example of the filter wrapper paper


122


having the embossment


13


.

FIG. 3A

is an enlarged plan view and

FIG. 3B

is an enlarged cross-sectional view taken along the line IIIB—IIIB in FIG.


3


A.




The embossment


13


applied to the filter wrapper paper


122


shown in

FIGS. 3A and 3B

has a rectangular lattice (square lattice or rectangular lattice) groove pattern. It is formed on the entire surface of the filter wrapper paper


122


. The embossment


13


is formed by embossing by means of a knurling member or the like.

FIGS. 3A and 3B

show grooves


131


-


a




1


to


131


-


a




5


extending parallel to each other in a left-right direction of the drawings (hereinafter referred to also as a “horizontal” direction, which may be, for example, substantially perpendicular to the direction of arrangement of the ventilation apertures


16


of the tip paper sheet


15


). Also shown are grooves


131


-


b




1


to


131


-


b




4


extending parallel to each other and in a direction perpendicular to the grooves


131


-


a




1


to


131


-


b


(hereinafter referred to also as “vertical direction”). Each of the regions defined by the grooves


131


-


a




1


to


131


-


a




5


and


131


-


b




1


to


131


-


b




4


constitutes a projection


132


projected as a prismoid, which is rectangular in a plan view.




Preferable dimensions of the embossment


13


including the thickness of the filter wrapper paper


122


will be described. Referring to

FIGS. 3A and 3B

, A denotes the length of a substantially flat top surface of the projection


132


along the vertical direction; A′ the length thereof along the horizontal direction; B the distance between the bottom edge of the projection


132


and the top surface edge thereof along the vertical direction; B′ the distance between the bottom edge of the projection


132


and the top surface edge thereof along the horizontal direction; C the width of the groove extending along the horizontal direction; C′ the width of the groove extending along the vertical direction; D the embossment pitch along the vertical direction (A+2B+C); D′ the embossment pitch along the horizontal direction (A′+2B′+C′); E the depth of each groove (the depth of the embossment); and F the thickness of the filter wrapper paper


122


(before embossing). In this case, preferable dimensions fall within the following ranges:




A and A′: 30-1000 μm (each)




B and B′: 30-1000 μm (each)




C and C′: 30-1000 μm (each)




D and D′: 100-3000 μm (each)




E: 10-100 μm




F: 10-100 μm




According to the present invention, in particular, if the embossment is too shallow, an expected effect cannot be obtained. If it is too deep, a defect (defect in adhesion of the filter wrapper paper


122


and the tip paper sheet) may be caused in tobacco making by a tobacco-making machine. In the present invention, as indicated above, the depth of the embossment is preferably 10-100 μm (0.01-0.1 mm), more preferably 30-60 μm (0.03-0.06 mm). the depth of the embossment can be measured by a pin-sensing three-dimensional roughness tester (for example, SE-3AK produced by Kosaka Laboratory).




Further, in the present invention, if the embossment pitch is too large, the groove may be filled with an adhesive and an expected effect cannot be obtained. As indicated above, the embossment pitch is preferably, 100-3000 μm (0.1-3 mm), more preferably 300-1000 μm (0.3-1 mm).





FIG. 4

is a plan view of a filter wrapper paper


122


with an embossment


13


having an oblique lattice groove pattern. In the embossment shown in

FIG. 4

, the width of a groove


131




a


and a groove


131




b


diagonally extending across the groove


131




a


, the depth (depth of the embossment) and the embossment pitch are the same as those described above with reference to

FIGS. 3A and 3B

. As clearly shown in

FIG. 4

, in this invention, the embossment


13


need not be formed in a adhering portion


41


at which end portions of the filter wrapper paper


122


are adhered together.




In the present invention, the filter wrapper paper and the tip paper may be adhered together substantially excluding a ventilation aperture-forming region of the tip paper. In this case, for example, as shown in

FIG. 5

, an adhesive


51


is applied to all rear surface of the tip paper sheet


15


except for a region


52


where the ventilation apertures


16


of the tip paper


15


are formed. More specifically, in this case, the filter wrapper paper and the tip paper are adhered together selectively at projections (that is, only at projections) of the embossment of the filter wrapper paper in a portion substantially excluding the ventilation aperture-forming region of the tip paper sheet. In other words, as exaggeratedly shown in

FIG. 6

, the filter wrapper paper


122


having the embossment


13


and the tip paper having the ventilation apertures


16


, which collectively cover the individual filter wrapper paper


123


wrapped around the filter member


121


, can be adhered to each other by the adhesive layer


51


only at the top surfaces of the projections


132


of the embossment in the region excluding the ventilation aperture


16


-forming region


52


(spot gluing). As described before with reference to

FIG. 5

, the adhesive


51


can be applied to substantially all region except for the ventilation aperture


16


-forming region


52


. However, on the side of the filter wrapper paper


122


, the adhesive is brought into contact with only the projections of the embossment


13


(point contact). Depending on the method for forming ventilation apertures, the adhesive can be applied also over the ventilation aperture-forming region.




The adhesive


51


for adhering the filter wrapper paper


122


and the tip paper


15


may be mainly composed of polyvinyl acetate or an ethylene/vinyl acetate copolymer as conventionally used. To achieve the above spot gluing, it is preferable that the viscosity of the adhesive at its application. be at least 500 cPs, more specifically, 500 to 5000 cPs, and particularly preferably, 500 to 3000 cPs (measured by a BL-type rotating viscometer using the rotor No. 3 at 30 rpm and 30° C.).




Owing to the above structure, in the filter-tipped cigarette of the present invention, the adhesion between the filter wrapper paper


122


and the tip paper sheet


15


is alleviated by the embossment


13


, thereby improving the air permeability through the ventilation apertures


16


to the filter wrapper paper


122


. In addition, since the filter wrapper paper


122


and the tip paper


15


are adhered by spot gluing, a gas passage from the region


52


at which the ventilation apertures


16


are formed (ventilation region) to the mouthpiece end of the filter


12


is constituted by a concave (groove) of the embossment


13


. A part of the diluting air flowing in from the ventilation apertures


16


of the tip paper


15


flows through the gas passage via the ventilation region


52


. The other part thereof passes the filter wrapper paper


122


via the ventilation region


52


and flows into the filter member


121


. On the other hand, a part of mainstream smoke of the tobacco is passed through the gas passage from the tip end of the filter member


121


(the end opposite to the mouthpiece end). It is pushed by the part of the diluting air flowing in via the ventilation region


52


and passed through the filter wrapper paper


122


, and joins the other part of the mainstream smoke which has passed through the filter member


121


from the tip end. Thus, in the filter-tipped cigarette of the present invention, the Vf value can be large and the variations thereof can be small.




EXAMPLE 1




The embossment


13


having a square lattice groove pattern (see

FIGS. 3A and 3B

) is formed on the overall filter wrapper paper


122


except for a adhering portion. This filter wrapper paper


122


was used to prepare filter-tipped cigarettes (the overall length: 84 mm, the circumference: 25 mm) having the dual structure as shown in

FIG. 2

to meet the following specifications. The filter wrapper paper and the tip paper were adhered by a vinyl acetate-based adhesive (the viscosity: 1000 cPs).




Specification of the Cigarettes




<Tobacco Rod


11


>




Air permeation resistance: 80 mmH


2


O




<Filter


12


>




Conventional dual filter




Length: 25 mm




Individual filter wrapper paper


123






Air Permeability: 10000 CORESTA units




Filter wrapper


122






Air Permeability: 2000 CORESTA unit




Embossing of a square lattice groove pattern




Embossment depth: 40 μm




Embossment pitch: indicated in Table 1




<Tip paper sheet


15


>




Lasered apertures (ventilation apertures


16


) in 2 lines




Air Permeability: 1000




100 samples of each of the above cigarettes were prepared and set to a ventilation meter. Then the filter ventilation ratio of each sample was measured. In the cigarettes of the present invention with the filter wrapper paper


122


having the embossment, it was observed that the filter wrapper paper


122


and the tip paper were adhered by spot gluing. However, in the comparative samples with a filter wrapper paper having no embossment, they were adhered by overall gluing.




The results are indicated in Table 1. In the table, Ave denotes an average value of the filter ventilation ratio, SD denotes a standard deviation, and CV denotes a coefficient of variation represented by the following equation: CV=(SD/Ave)×100(%) (the same applies to the subsequent examples).












TABLE 1











The relationship between the






embossment pitch and Vf
















Embossment Pitch (mm)



















No











embodiment




2.1




1.06




0.64





















Ave (%)




32.2




43.0




49.2




54.9







SD (%)




2.3




2.7




2.9




2.9







CV (%)




7.1




6.3




5.9




5.3















As shown in Table 1, it was observed that the ventilation ratio was improved and variations in the filter ventilation ratio were smaller in the samples according to the present invention as compared to the comparative sample having no embossment. In particular, it is understandable that the smaller the embossment pitch, the smaller the variations in Vf value.




EXAMPLE 2




Filter-tipped cigarettes as indicated in the following Tables 2 to 4 were prepared in the same manner as in the case of Example 1, except that the embossment pitch was set to 2.1 mm or 0.64 mm and the embossment depth was varied. Then, the Vf values of the these cigarettes were measured. In the cigarettes of the present invention with the filter wrapper paper


122


having the embossment, it was observed that the filter wrapper paper


122


and the tip paper were adhered by spot gluing. However, in the comparative samples with filter wrapper paper having no embossment, they were adhered by overall gluing.




The results are indicated in Tables 2 to 4.












TABLE 2











the relationship between the embossment






depth and Vf in the case where embossment pitch






is 2.1 mm













Embossment Depth (μm)


















No












embossment




25




34




44




47




53




















Ave (%)




31.4




37.0




38.6




42.2




43.2




44.2






SD (%)




3.2




3.0




2.5




2.3




2.6




2.3






CV (%)




10.2




8.1




6.5




5.5




6.0




5.2






















TABLE 3











the relationship between the embossment






depth and Vf in the case where embossment pitch is






0.64 mm













Embossment Depth (μm)


















No












embossment




18




23




26




40




47




















Ave (%)




33.1




44.5




46.8




49.2




54.0




57.9






SD (%)




3.5




3.2




3.2




2.9




2.9




2.4






CV (%)




10.6




7.2




6.8




5.9




5.3




4.1






















TABLE 4











the relationship between the embossment






depth and Vf in the case where embossment pitch is






0.64 mm













Embossment Depth (μm)


















No












embossment




17




24




28




36




46




















Ave (%)




32.6




45.4




49.0




52.0




54.6




59.2






SD (%)




3.8




3.3




3.4




2.8




2.4




2.5






CV (%)




11.7




7.3




6.9




5.4




4.4




4.2














As shown in Tables 2 to 4, it was observed that the ventilation ratio was improved and variations in the filter ventilation ratio were smaller in the samples according to the present invention as compared to the comparative samples having no embossment.




As has been described above, the present invention can decrease the variations of the Vf values as well as improve Vf of the filter-tipped cigarette. In other words, the filter ventilation of the cigarette can be controlled reliably. Thus, it is possible to stably provide a desired amount of a smoke component.




Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.



Claims
  • 1. A filter-tipped cigarette comprising:a tobacco rod including a tobacco filler and a tobacco wrapper paper wrapped around the tobacco filler; a filter including a filter member and a filter wrapper paper integrally wrapped around the filter member; and a tip paper having a plurality of apertures arranged along a circumferential direction thereof, and connecting the tobacco rod and the filter, the filter wrapper paper having an embossment on substantially an entire surface thereof, and the filter wrapper paper and the tip paper being adhered to each other by spot gluing at projections of the embossment of the filter wrapper paper.
  • 2. The filter-tipped cigarette according to claim 1, wherein the filter wrapper paper and the tip paper are adhered except for a region where the plurality of apertures are formed.
  • 3. The filter-tipped cigarette according to claim 1, wherein the embossment has a depth of 10 to 100 μm.
  • 4. The filter-tipped cigarette according to claim 2, wherein the embossment has a depth of 10 to 100 μm.
  • 5. The filter-tipped cigarette according to claim 1, wherein the embossment has an emboss pitch of 100 to 3000 μm.
  • 6. The filter-tipped cigarette according to claim 2, wherein the embossment has a pitch of 100 to 3000 μm.
  • 7. The filter-tipped cigarette according to claim 3, wherein the embossment has an emboss pitch of 100 to 3000 μm.
  • 8. The filter-tipped cigarette according to claim 4, wherein the embossment has an emboss pitch of 100 to 3000 μm.
Priority Claims (1)
Number Date Country Kind
10-317867 Nov 1998 JP
CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation Application of PCT Application No. PCT/JP99/06211, filed Nov. 8, 1999, which was not published under PCT Article 21(2) in English.

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Continuations (1)
Number Date Country
Parent PCT/JP99/06211 Nov 1999 US
Child 09/851339 US