HK1005840B

HK1005840B - Coaxial filter cigarette

Info

Publication number: HK1005840B
Application number: HK98105016.2A
Authority: HK
Inventors: Schneider Werner; Muller Bernd-Henrik; Rudolph Gert
Original assignee: British-American Tobacco(Germany)Gmbh
Priority date: 1991-08-19
Filing date: 1998-06-06
Publication date: 1999-01-29

Description

The invention relates to a coaxial filter cigarette of the type specified in the notion of claim 1.

Err1:Expecting ',' delimiter: line 1 column 101 (char 100)

Further versions of such coaxial cigarettes are shown in FR-PS 13 22 254, US-PS 3 614 956, US-PS 4 219 031, GB-OS 20 70 409, GB-PS 10 86 443 and DE-OS 36 02 846.

In addition, a coaxial cigarette with an inner hollow tube and a narrow-draught aerosol production zone is known from USPS 3 356 094; however, the manufacture of this coaxial cigarette is very complex and therefore expensive; in addition, the various components are separated from each other, resulting in an unusual smoke pattern.

A coaxial filter cigarette is known from DE-PS 37 43 597 and has a strand and a filter part, the strand containing an inner core of a largely non-residue glossy material, in particular tobacco material, a casing for the inner core, an outer coating of a tobacco and/or non-tobacco material and an outer coating for the inner core or its coating, which is coaxial.

The filter component shall have a filter core, an airtight envelope for the filter core, a filter coating and a coating for the filter coating.

The basic principle of this coaxial filter cigarette is to distinguish in the radial direction two areas, namely the area of the main heat source on the one hand and the area where the main part of the aerosol entering the smoker's mouth is produced on the other hand.

The problem with such a design of a coaxial filter cigarette is the reduction of second-hand smoke, which can be achieved only with great effort.

Another coaxial filter cigarette is known from DE-PS 39 01 226, which also has a strand and a filter part, the strand part containing an inner core of a material which is largely free of residues, a basically airtight casing, an outer shell which coaxially surrounds the inner core or its casing and a casing for the outer shell.

The zone used only as a heat source and the zone where the bulk of the aerosol entering the smoker's mouth is produced are separated by space, which essentially means that the smoke entering the smoker's mouth has a high proportion of taste-related components and a very low proportion of unwanted combustion products.

However, since the mixture in the strand usually produces such large amounts of smoke that the coaxial filter element alone is not sufficient for filtering, diffusion and ventilation elements are additionally arranged between the filter element and the strand, with additional intermediate elements and external channels if necessary.

The common feature of these two known coaxial filter cigarettes is that a significant reduction in secondary smoke can only be achieved by the use of special paper, especially very low air permeability cigarette paper with special additives.

According to its general concept, claim 1 is based on European patent application EP 0 365 882, which concerns a coaxial cigarette which, even without a filter, produces a low CO2 emission at a satisfactory smoke level, while being reduced in secondhand smoke.

Err1:Expecting ',' delimiter: line 1 column 484 (char 483)

The purpose of the invention is therefore to create a coaxial filter cigarette of the specified type which does not present the above disadvantages and in particular allows a significant reduction in secondhand smoke.

This is achieved by the inventive nature of the characteristics of claim 1.

Appropriate implementations shall be defined by the characteristics of the subclaim.

The advantages of the invention are that a greater proportion of the smoke produced is directed into the main smoke than in the known coaxial versions and in the case of normal strands, so that a large proportion of the smoke which normally enters the secondary smoke after it is produced is also redirected into the main smoke when conventional cigarette paper is used, and the increased proportion of the main smoke is then filtered by a correspondingly more effective filter.

Whether the main heat production zone is located in the inner core or in the outer shell and the aerosol production zone is located in the outer core or in the inner shell, the main smoke is distributed from the secondary smoke to the main smoke by means of the special coaxial strand type, which, unlike the known measures, allows the use of special cigarette papers, especially very low air permeability cigarette papers with additives to reduce secondary smoke, which also avoids the consequent increase in the carbon monoxide content of the main smoke.

Finally, the design of the coaxial filter cigarette according to the invention allows not only the quantity but also the quality of the secondary smoke to be controlled, which is largely independent of the mixture determining the quality of the main smoke, as was not possible with previously known secondary smoke reducing solutions.

For example, the preferred focus in the selection of peripheral tobacco can now be on minimising the precursor of irritating tobacco ingredients.

The invention is explained in detail below by means of examples of execution, referring to the accompanying schematic drawing, the only figure of which shows an axial cut by a coaxial filter cigarette.

The coaxial filter cigarette shown in Figure 1, generally referred to by the reference sign 10, has a strand 12 to which, by the usual manufacturing techniques, a coaxial filter section 13 is attached.

The filter part 13 shall have a coaxial filter element 15 consisting of a filter core 22 with a casing 24 and a filter coat 26 with a casing 28.

The ventilation medium is indicated as a line of point-like ventilation openings 30 extending over the circumference of the coaxial filter element and through the unrepresented coating paper.

The coaxial strand is used for the production of smoke and has a length of 25 to 85 mm and a diameter of 7 to 9 mm, i.e. the usual dimensions of conventional cigarettes.

The inner core 14 of the strand has a diameter of 40 to 80%, preferably 60 to 70% of the outer diameter of the cigarette. The material of the inner core 14 is designed with a packing density of 190 to 250 mg/cm3, preferably 210 to 230 mg/cm3. Additives are added to the material of the inner core 14 to control combustion if necessary. The material of the inner core is such that the tensile resistance per unit length, relative to the packing density, is 0.09 to 0.15, preferably 0.1 to 0.12 (mmWs) cm2/mg.

The wrap 16 of the inner core of strand 12 shall consist of paper, film of tobacco material or other suitable material and shall have an air permeability of less than 30 ISO units, preferably less than 10 ISO units.

The outer shell 18 surrounds the inner core or its envelope 16 coaxially. The material of the outer shell 18 is designed with a packaging density of 140 to 200 mg/cm3, preferably 150 to 180 mg/cm3. The ratio of tensile strength per unit length to packaging density is 0.035 to 0.08, preferably 0.04 to 0.05 (mmWs) cm2/mg.

The outer coat of 18 of strand 12 casing 20 has an air permeability of less than 40 ISO units, preferably 15 to 25 ISO units, and consists of cigarette paper, which may be standard paper. Specialised papers for reducing secondary smoke may also be used. Outer coat of 18 casing 20 contains additives to control combustion, if necessary.

Where appropriate, the outer wrapper 20 of outer sheath 18 of strand 12 may be provided with segment perforations to control the temperature gradient in outer sheath 18; the use and/or design of these segment perforations depends on the other materials used.

Similar to strand 12 the coaxial filter 15 consists of a filter core 22 with a casing 24 and a filter coat 26 with a casing 28.

In a first embodiment, the inner core 14 is filled with so-called fillers, i.e. filler tobacco, usually of lower quality, and/or ribs. Tobacco film is also suitable. The wrapper 16 of the inner core 14 is a paper or tobacco film with the air permeability described. The outer cover 18 consists of aromatic tobacco, which is essentially responsible for the production of the taste-relevant aerosol.

The filter core 22 has a diameter up to 2 mm larger than the diameter of the inner core of the strand and has a retention rate in the filter core of over 90%, preferably over 95%, at ventilation rates of 30 to 80% of the filter. This filters the main vapour in a favourable way. The filter coating 26 has a retention rate of less than 30%, so that the filtration of the taste-relevant aerosol is less, which gives a positive taste. The retention rates refer to the total mass of the nicotine-free dry cat entering the respective filter zone.

The materials for the two filter zones, namely the filter core 22 and the filter coating 26, are the usual filter materials currently used in the cigarette industry.

In a second embodiment, the inner core consists of aromatic tobacco, while the outer coat of tobacco strand 18 contains 12 fillers, ribs or tobacco foil. For this purpose, for example, flue cured tobacco of lower leaf stands may be used. The filter 15 is then constructed so that the filter core 22 has a smaller diameter than the inner core 14 and a retention rate of less than 30%. The outer core has a corresponding retention rate of more than 90%.

The effect of the invention on conventional cigarettes is illustrated by an example, in which a coaxial cigarette manufactured according to the above specifications and formed without a filter was compared with a normal filterless cigarette, because the invention does not primarily concern filter effects but a special coaxial structure in the string part, which realizes the redistribution of the secondary smoke into the main smoke. Other

The main smoke condensate is usually determined according to the standard of use, while the secondary smoke is captured during the use and the condensate is determined. The values obtained show that, for approximately the same total smoke condensate, i.e. from the main and secondary smoke, the secondary smoke condensate of the cigarette of the invention is about 20% lower than that of the comparison sample. The ratio of main smoke to secondary smoke condensate increases from 1.0 for the conventional sample to 1.4 for the cigarette of the invention. Nevertheless, the total volume of CO determined after the use remains practically the same at 21 ml compared to 20 ml in the main smoke.

Although coaxial filters with the specified specifications are particularly preferred, known ventilated nozzles or filters that allow a minimum filter ventilation rate of 40% and result in a retention rate of at least 40% (based on the total mass of the nicotine-free dry condensate flowing into the filter) are also suitable for use with the tobacco strands specified above.

Claims

A coaxial filter cigarette,
a) comprising a rod portion
a1) having an inner core of a tobacco and/or non-tobacco material smouldering substantially without residue,

a2) a sheath for the inner core,

a3) an outer jacket of a tobacco and/or non-tobacco material surrounding the inner core and/or its sheath, and

a4) a sheath for the outer jacket, and

b) comprising a filter portion, with

c) the inner core (14) having a diameter that amounts to 45 to 80% of the outer diameter of the filter cigarette (10), and

d) the packing density of the inner core (14) being greater than the packing density of the outer jacket (18), characterized in that

e) the draw resistance per length unit with respect to the packing density is greater in the inner core (14) than in the outer jacket (18), that

f) the air permeability of the sheath (16) of the inner core (14) is less than the air permeability of the sheath (20) of the outer jacket (18), and that

g) the filter portion (13) has a filter ventilation degree of at least 30% and a retention degree of at least 40%.
A coaxial filter cigarette according to claim 1, characterized in that the inner core (14) has a packing density of 190 to 250 mg/cm³.
A coaxial cigarette according to any of claims 1 to 2, characterized in that the draw resistance per length unit with respect to the packing density is 0.09 to 0.15 (mm R) cm²/mg in the inner core (14).
A coaxial cigarette according to any of claims 1 to 3, characterized in that the inner core (14) of the rod portion (12) contains additives used for controlling the thermal processes.
A coaxial cigarette according to any of claims 1 to 4, characterized in that the sheath (16) of the inner core (14) has an air permeability of less than 30 ISO units.
A coaxial cigarette according to any of claims 1 to 5, characterized in that the packing density of the outer jacket (18) is 140 to 200 mg/cm³.
A coaxial cigarette according to any of claims 1 to 6, characterized in that the draw resistance per length unit with respect to the packing density is 0.035 to 0.08 (mm R) cm²/mg in the outer jacket (18).
A coaxial cigarette according to any of claims 1 to 7, characterized in that the outer jacket (18) of the rod portion (12) contains additives used for controlling the thermal processes.
A coaxial cigarette according to any of claims 1 to 8, characterized in that the sheath (20) of the outer jacket (18) has an air permeability of less than 40 ISO units.
A coaxial cigarette according to any of claims 1 to 9, characterized in that the sheath (20) of the outer jacket (18) of the rod portion (12) contains additives for controlling the thermal processes.
A coaxial cigarette according to any of claims 1 to 10, characterized in that a coaxial filter portion (13) with a filter core (22), the inner diameter of which is approximately equal to the diameter of inner core (14) of the rod portion (12), and with a filter jacket (26) is provided.
A coaxial cigarette according to any of claims 1 to 11, characterized in that the inner core (14) consists of aroma-rich tobaccos, and the outer jacket (18) consists of fillers.
A coaxial cigarette according to any of claims 11 or 12, characterized in that, at ventilation degrees of 30 to 80%, the filter portion (13) results in respective retention degrees of less than 30% in the filter core (22) and more than 90% in the filter jacket (26).
A coaxial cigarette according to any of claims 11 to 13, characterized in that the inner diameter of the filter core (22) is slightly less than the inner diameter of the inner core (14).
A coaxial cigarette according to any of claims 1 to 11, characterized in that the inner core (14) consists of fillers, and the outer jacket (18) consists of aromarich tobaccos.
A coaxial cigarette according to claim 15, characterized in that, at ventilation degrees of 30 to 80%, the filter portion (13) results in respective retention degrees of more than 90% in the filter core (22) and less than 30% in the filter jacket (26).
A coaxial cigarette according to claim 16, characterized in that the inner diameter of the filter core (22) is slightly larger than the inner diameter of the inner core (14).