GB2135168A

GB2135168A - Cigarette filter

Info

Publication number: GB2135168A
Application number: GB08403841A
Authority: GB
Inventors: Urs Nyffeler
Original assignee: Fabriques de Tabac Reunies SA
Current assignee: Philip Morris Products SA
Priority date: 1983-02-16
Filing date: 1984-02-14
Publication date: 1984-08-30
Also published as: GB8403841D0

Abstract

A filter cigarette comprises a rod (2) of filter material (10) optionally wrapped in a filter wrapper (12). The filter rod, and filter wrapper if present, is provided with peripheral grooves (14) which are open at the mouth end of the rod. The rod and the filter wrapper present, are overwrapped in the finished cigarette by a tipping wrapper (16), which admits ventilating air into the grooves and extends beyond the mouth end of the filter rod to a distance of 0.5 to 5 mm. The tipping wrapper is sufficiently stiff to prevent interference with the performance of the filter by the lips or mouth of the smoker. <IMAGE>

Description

SPECIFICATION Cigarette filter This invention relates to cigarette filters and, in particular, to filter mouthpieces which make provision for dilution of smoke by air.

Cigarette filters are known which comprise a rod of fibrous or other filter material, which may be surrounded by a peripheral wrapper (or peripheral surface) which may itself be impervious to air or smoke, one or more generally Iongtitudinal grooves or channels being formed in the peripheral region of the filter rod (and the wrapper when present), extending at least part of the length of the filter and opening at the mouth end of the filter. In the finished cigarette, such a filter is further enclosed in an outer or tipping wrapper which usually secures the filter to the tobacco rod of the cigarette and is capable of admitting air to the grooves or channels, either through openings or perforations formed in the tipping or by its overall porosity.

It has been found that the performance of such filters can be affected by the lips of the smoker, when the cigarette is placed in the mouth or when smoke is drawn in during the act of smoking.

It is an object of the invention to provide a filter and cigarette structure that is less subject to interference by thor actions of the smoker during smoking.

According to this invention, in a filter cigarette of the above type, the outer or tipping wrapper alone extends beyond the filter rod at the mouth end of the filter by a distance of 0.5 to 5mm. Viewed in another way, the same cigarette can be defined as one in which the entire filter body, including the mouths of the grooves or channels and any separate filter wrapper (when present) is recessed within the tipping wrapper by the stated distance from the mouth end of the tipping.

Notwithstanding the avoidance of interference with the function of the filter by the smoker's lips, all the beneficent advantages of filters of this type can be maintained, and it is particularly preferred that the tipping wrapper should extend between about 2 and 3mm beyond the end of the filter body. Inevitably, if interference by the smoker's lips is to be avoided, the tipping material will have sufficient stiffness to resist distortion by the lips.

There is an important additional advantage of the invention in that it enables filter efficiency to be substantially increased, for example by up to 40 percent, depending on the degree of dilution, by keeping the resistance to draw substantially constant throughout the length of the filter rod.

The accompanying drawing is a perspective view of a filter cigarette embodying the invention, in which the tipping wrapper is partly unrolled.

in the drawing, the cigarette includes a filter 2 which is aligned with and in smoke flow communication with the end of a wrapped tobacco rod 3. The filter consists of a rod of any conventional filter material 10, which may be enclosed in a peripheral wrapper filter 12 which is preferably impermeable by air or by smoke. One or more grooves 14 are impressed in the periphery of the rod of filter material 10 and the filter wrapper 12 to provide channels through which ventilating air can reach the mouth of the the smoker. The grooves are open at the mouth end of the filter but can extendalong the length of the filter for any desired distance. Preferably, however they are closed from the tobacco rod 3, for example by terminating at an intermediate point along the filter.

The filter wrapper 12, when present, may be formed separately from the filter rod, for example as a sheet of paper or plastics material wrapped around the filter material during formation of the rod, or may be integral with the rod, for example by heat sealing of the surface of the rod during formation of the grooves 14 The filter 2 is further enclosed in, and is also secured to the tobacco rod 3 by, an outer or tipping wrapper 16 which overlaps with the tobacco rod at one end and extends beyond the end of the filter at the mouth end of the cigarette, preferably the tipping extends from 0.5 to 5mm beyond the end of the filter 2. Thus, as can be seen in the drawing, the planar end of the filter body and its associated filter wrapper is recessed within the tipping wrapper.As mentioned above, the tipping will have sufficient stiffness to resist interference by the smoker's lips with the performance of the filter and its channels.

In the embodiment shown, the tipping has at least one circumferantial row of perforations 18 through which air can be reach the channels 14 and the tipping material as such in this case can be impermeable, if desired. Alternatively, a tipping material of such porosity can be employed that the desired amount of air can be admitted through the material itself.

1. Afilter cigarette including a tobacco rod and a rod of filter material in communication therewith, the filter rod having one or more grooves or channels formed in the peripheral region thereof which extend over at least part of the length of the filter and open at the mouth end thereof, and an outer or tipping wrapper surrounding the filter and capable of admitting air to the grooves or channels, in which the outer wrapper alone extends beyond the filter rod at the mouth end thereof by a distance of0.Sto 5mm.

2. A filter cigarette including a tobacco rod and a rod of filter material in communication therewith, the filter rod having one or more grooves or channels formed in the peripheral region thereof which extend over at least part of the length of the filter and open at the mouth end thereof, and an outer or tipping wrapper surrounding the filter and capable of admitting air to the grooves or channels, the entire filter body including any associated filter wrapper teminating within the tipping wrapper at a distance of 0.5 to 5mm from the mouth end of the tipping wrapper.

3. A filter cigarette according to claim 1 or 2, in which the grooves or channels do not extend into communication with the tobacco rod.

4. A filter cigarette according to claim 1,2 or 3, in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Cigarette filter This invention relates to cigarette filters and, in particular, to filter mouthpieces which make provision for dilution of smoke by air. Cigarette filters are known which comprise a rod of fibrous or other filter material, which may be surrounded by a peripheral wrapper (or peripheral surface) which may itself be impervious to air or smoke, one or more generally Iongtitudinal grooves or channels being formed in the peripheral region of the filter rod (and the wrapper when present), extending at least part of the length of the filter and opening at the mouth end of the filter. In the finished cigarette, such a filter is further enclosed in an outer or tipping wrapper which usually secures the filter to the tobacco rod of the cigarette and is capable of admitting air to the grooves or channels, either through openings or perforations formed in the tipping or by its overall porosity. It has been found that the performance of such filters can be affected by the lips of the smoker, when the cigarette is placed in the mouth or when smoke is drawn in during the act of smoking. It is an object of the invention to provide a filter and cigarette structure that is less subject to interference by thor actions of the smoker during smoking. According to this invention, in a filter cigarette of the above type, the outer or tipping wrapper alone extends beyond the filter rod at the mouth end of the filter by a distance of 0.5 to 5mm. Viewed in another way, the same cigarette can be defined as one in which the entire filter body, including the mouths of the grooves or channels and any separate filter wrapper (when present) is recessed within the tipping wrapper by the stated distance from the mouth end of the tipping. Notwithstanding the avoidance of interference with the function of the filter by the smoker's lips, all the beneficent advantages of filters of this type can be maintained, and it is particularly preferred that the tipping wrapper should extend between about 2 and 3mm beyond the end of the filter body. Inevitably, if interference by the smoker's lips is to be avoided, the tipping material will have sufficient stiffness to resist distortion by the lips. There is an important additional advantage of the invention in that it enables filter efficiency to be substantially increased, for example by up to 40 percent, depending on the degree of dilution, by keeping the resistance to draw substantially constant throughout the length of the filter rod. The accompanying drawing is a perspective view of a filter cigarette embodying the invention, in which the tipping wrapper is partly unrolled. in the drawing, the cigarette includes a filter 2 which is aligned with and in smoke flow communication with the end of a wrapped tobacco rod 3. The filter consists of a rod of any conventional filter material 10, which may be enclosed in a peripheral wrapper filter 12 which is preferably impermeable by air or by smoke. One or more grooves 14 are impressed in the periphery of the rod of filter material 10 and the filter wrapper 12 to provide channels through which ventilating air can reach the mouth of the the smoker. The grooves are open at the mouth end of the filter but can extendalong the length of the filter for any desired distance. Preferably, however they are closed from the tobacco rod 3, for example by terminating at an intermediate point along the filter. The filter wrapper 12, when present, may be formed separately from the filter rod, for example as a sheet of paper or plastics material wrapped around the filter material during formation of the rod, or may be integral with the rod, for example by heat sealing of the surface of the rod during formation of the grooves 14 The filter 2 is further enclosed in, and is also secured to the tobacco rod 3 by, an outer or tipping wrapper 16 which overlaps with the tobacco rod at one end and extends beyond the end of the filter at the mouth end of the cigarette, preferably the tipping extends from 0.5 to 5mm beyond the end of the filter 2. Thus, as can be seen in the drawing, the planar end of the filter body and its associated filter wrapper is recessed within the tipping wrapper.As mentioned above, the tipping will have sufficient stiffness to resist interference by the smoker's lips with the performance of the filter and its channels. In the embodiment shown, the tipping has at least one circumferantial row of perforations 18 through which air can be reach the channels 14 and the tipping material as such in this case can be impermeable, if desired. Alternatively, a tipping material of such porosity can be employed that the desired amount of air can be admitted through the material itself. CLAIMS

4. A filter cigarette according to claim 1,2 or 3, in which the outer wrapper extends 2-3 mm beyond the filter rod at the mouth end.

5. A filter cigarette according to any of claims 1 to 4, in which the filter material is surrounded by a filter wrapper and the grooves or channels are formed in the filter material and the wrapper.

6. A filter cigarette according to claim 5, in which the filter wrapper is impermeable.

7. A filter cigarette substantially as described with reference to the accompanying drawings.