Smoking article mouthpiece

Abstract

A mouthpiece or filter element comprising a longitudinally extending hollow rod of filtering material having inner and outer surfaces, the inner surface defining at least one longitudinally extending channel which extends along the full length of the mouthpiece or filter element, wherein the distance between the inner and outer surfaces is 1 mm or less, wherein the filtering material of the mouthpiece or filter element comprises a plasticiser, wherein the amount of plasticiser present in the filtering material is less than 21.5%.

Claims

1. A mouthpiece or filter element comprising a longitudinally extending hollow rod of filtering material having inner and outer surfaces, the inner surface defining at least one longitudinally extending channel which extends along the full length of the mouthpiece or filter element, wherein the distance between the inner and outer surfaces is 1 mm or less, wherein the filtering material of the mouthpiece or filter element comprises a plasticiser, wherein the amount of plasticiser present in the filtering material is from 15% to 19% by total weight of the filtering material and plasticiser.

2. A mouthpiece or filter element comprising a longitudinally extending hollow rod of filtering material having inner and outer surfaces, the inner surface defining at least one longitudinally extending channel which extends along the full length of the mouthpiece or filter element, wherein the distance between the inner and outer surfaces is 1 mm or less, wherein the filtering material of the mouthpiece or filter element comprises a plasticiser, wherein the amount of plasticiser present in the filtering material is less than 17.5% by total weight of the filtering material and plasticiser.

3. A mouthpiece or filter element according to claim 1 wherein the distance between the inner and outer surfaces is from 0.3 mm to 0.95 mm, preferably from 0.3 mm to 0.9 mm.

4. A mouthpiece or filter element according to claim 1 wherein the distance between the inner and outer surfaces is from 0.5 mm to 0.8 mm.

5. A mouthpiece or filter element according to claim 1 wherein the amount of plasticiser present is from 15% to 18.3% by total weight of the filtering material and plasticiser.

6. A mouthpiece or filter element according to claim 1 wherein the amount of plasticiser present is from 18.5% to 19% by total weight of the filtering material and plasticiser.

7. A mouthpiece or filter element according to claim 1 wherein the amount of plasticiser present is from 15% to 17.9% by total weight of the filtering material and plasticiser.

8. A mouthpiece or filter element according to claim 1 wherein the amount of plasticiser present is from 18.1% to 19% by total weight of filtering material and plasticiser.

9. A filter smoking article comprising a mouthpiece or filter element according to claim 1 joined at one end to a tobacco rod.

10. A filter smoking article according to claim 9 wherein the mouthpiece or filter element is wrapped by a plugwrap, the plugwrap having a weight from 20 to 50 grams per square meter.

11. A method of making a mouthpiece or filter element of claim 1, comprising a step of passing a filtering material to which a plasticiser has been applied through a shaping means while heat treating the filtering material to thereby form a longitudinally extending hollow rod of filtering material having inner and outer surfaces, the inner surface defining at least one longitudinally extending channel which extends along the full length of the mouthpiece or filter element, the shaping means including a protruding inner rod (mandrel) extending through the shaping means having a cross-sectional profile equal to that of the cross section of the longitudinally extending channel, wherein the mandrel size is substantially equal to the cross section of the longitudinally extending channel.

12. A method according to claim 11 wherein the mandrel size is from 3.8 mm to 4.2 mm.

13. A method according to claim 11 wherein the filtering material is exposed to cooling air at a temperature of less than 25° C. after formation of the longitudinally extending hollow rod of filtering material.

14. A filter smoking article according to claim 10, wherein the plugwrap has a weight from 27 to 35 grams per square meter.

15. A method according to claim 11 wherein the filtering material is exposed to cooling air at a temperature of 22° C. to 25° C. after formation of the longitudinally extending hollow rod of filtering material.

Description

(1) The present invention will now be illustrated by way of examples with reference to the accompanying drawing, in which:

(2) FIG. 1 schematically illustrates a mouthpiece according to one embodiment of the present invention; and

(3) FIGS. 2A, 2B, 2C and 2D reproduce photographs of the ends of mouthpieces of four different embodiments of the invention.

EXAMPLE 1

(4) In FIG. 1, a mouthpiece 1 comprises a longitudinally extending hollow tubular rod 2 of cellulose acetate filamentary tow, having an inner surface 3 and an outer surface 4. The tubular rod has outer circumference 16 mm. The inner surface 3 defines a longitudinally extending channel 5 of circular cross section which extends along the full length of the filter element 1. The distance between the inner surface 3 and the outer surface 4 of cylindrical tubular rod 2, that is the wall thickness of rod 2, is 0.6 mm. The cellulose acetate filamentary tow used for filter element 1 weighs 0.45 grams and also contains 0.092 grams triacetin plasticiser. The percentage of plasticiser present by total weight of the filamentary tow and triacetin plasticiser is around 17%. This has been calculated using the general equation presented earlier, to give the result below.

(5) $\mathrm{Percentage}\mathrm{of}\mathrm{plasticiser}\%=\frac{0.092}{0.092+0.45}\times 100=17\%$

(6) The mouthpiece 1 of FIG. 1 is a longitudinally extending tubular rod 2 of length 6 mm and circumference 16 mm having annular cross section, the annular wall thickness being 0.6 mm.

(7) The mouthpiece 1 of FIG. 1 may be used alone as a single element filter, or may be used as an element of a multi-segment filter. Single and multiple element filters are well known in the art.

EXAMPLE 2

(8) The mouthpiece of the present invention (e.g. that of FIG. 1) may be produced in the following manner. A continuous bundle of cellulose acetate filamentary tow containing triacetin plasticiser (the percentage of plasticiser present by total weight of the filamentary tow and triacetin plasticiser is around 17%) is pulled through a fix die while the material is being heat treated, to form a longitudinally extending cylindrical rod of cellulose acetate tow. The rod has inner and outer substantially concentric surfaces, the inner surface defining a longitudinally extending channel which extends along the full length of the mouthpiece. The fixed die includes a protruding inner rod (mandrel) that extends through the fixed die, having a cross-sectional profile equal to that of the cross section of the longitudinally extending channel. The cellulose acetate rod is exposed to cooling air at temperature 22 to 25° C. after it is formed for an extended period of time (0.13 seconds). A mandrel of circular cross section and diameter 4.2 mm was used to form the mouthpiece of FIG. 1. These parameters result in the formation of a mouthpiece of Example 1 which has a wall thickness of 0.6 mm.

EXAMPLE 3

(9) FIGS. 2A, 2B, 2C and 2D shows photographs of the ends of mouthpieces of four different embodiments of the invention. These were produced by methods similar to that of Example 2, with use of different protruding inner rods (mandrels) that extend through the fixed die, having different cross-sectional profiles, to provide longitudinally extending channels having different cross-sectional profiles. As will be appreciated from Example 2, the longitudinally extending channel will have the same cross section as the mandrel used.

(10) The use of a hexagonal mandrel will provide a tubular element having a longitudinally extending channel of hexagonal cross section which extends along the full length of the filter element, as shown in FIG. 2A. It can be seen that the distance between the inner and outer surfaces of the mouthpiece/element shown in FIG. 2A at its narrowest point is 0.851 mm.

(11) The use of an octagonal mandrel will provide a tubular element having a longitudinally extending channel of octagonal cross section which extends along the full length of the filter element, as shown in FIG. 2B. It can be seen that the distance between the inner and outer surfaces of the mouthpiece/element shown in FIG. 2B at its narrowest point is 0.851 mm.

(12) The use of a twelve point star shaped mandrel will provide a tubular element having a longitudinally extending channel of twelve point star shaped cross section which extends along the full length of the filter element, as shown in FIG. 2C. It can be seen that the distance between the inner and outer surfaces of the mouthpiece/element shown in FIG. 2C at its narrowest point—at a point of the star of the channel—is 0.807 mm.

(13) The use of a ten point (with round ends) star shaped mandrel will provide a tubular element having a longitudinally extending channel of ten point (with round ends) star shaped cross section which extends along the full length of the filter element, as shown in FIG. 2D. It can be seen that the distance between the inner and outer surfaces of the mouthpiece/element shown in FIG. 2B at its narrowest point is 0.815 mm.

(14) FIGS. 2A, 2B, 2C and 2D illustrate that the present invention may provide mouthpieces (filters)/filter elements having walls of less than 1 mm (e.g. 0.3 mm to 0.95 mm thick) thick with longitudinally extending channels of different cross sections. The invention provides mouthpieces (filters)/filter elements with longitudinally extending channels with cross sections of very high shape definition even with very low levels of plasticiser. This high definition may be useful as an anti-counterfeit measure.