U.S. patent number 3,800,805 [Application Number 05/294,691] was granted by the patent office on 1974-04-02 for smoking articles.
This patent grant is currently assigned to Brown & Williamson Tobacco Corporation. Invention is credited to Geoffrey O. Brooks, Henry G. Horsewell, James W. P. Phelpstead.
United States Patent |
3,800,805 |
Horsewell , et al. |
April 2, 1974 |
SMOKING ARTICLES
Abstract
This invention relates to a smoking article or smoking-article
component having wrapped around it a band or strip of material
shrinkable by the heat of hot smoke from the approaching coal when
the article is smoked. Such a band may be wrapped around the
tobacco rod of the article near the end to be placed in the mouth,
around a filter or mouthpiece or around a body of smoke-impermeable
material disposed between the tobacco rod and a filter or
mouthpiece. Such a band may also be disposed inside a wrapping
section of perforated or air-pervious material so as to close the
said material against the passage of air until shrinkage
occurs.
Inventors: |
Horsewell; Henry G. (Totton,
EN), Phelpstead; James W. P. (Hedge End,
EN), Brooks; Geoffrey O. (Botley, EN) |
Assignee: |
Brown & Williamson Tobacco
Corporation (Louisville, KY)
|
Family
ID: |
10444259 |
Appl.
No.: |
05/294,691 |
Filed: |
October 3, 1972 |
Foreign Application Priority Data
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Oct 11, 1971 [GB] |
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47237/71 |
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Current U.S.
Class: |
131/338;
131/349 |
Current CPC
Class: |
A24D
3/041 (20130101) |
Current International
Class: |
A24D
3/04 (20060101); A24D 3/00 (20060101); A24d
001/10 () |
Field of
Search: |
;131/4A,10.3,8A,17A,171A,11 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
|
|
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|
|
72,589 |
|
Sep 1931 |
|
SW |
|
659,839 |
|
Jun 1965 |
|
BE |
|
1,553,960 |
|
Dec 1968 |
|
FR |
|
149,216 |
|
Nov 1952 |
|
AU |
|
Primary Examiner: Michell; Robert W.
Assistant Examiner: Pitrelli; John F.
Attorney, Agent or Firm: Finnegan, Henderson, Farabow &
Garrett
Claims
We claim:
1. A smoking article comprising: an elongated smoking article
component; a length of air permeable material wrapped about a
section of said component; a band of air impermeable, heat
shrinkable material disposed at least in part between said
component section and said air permeable material in position so as
normally to close the air permeable material against the passage of
air while at the same time leaving a longitudinal passage for smoke
through said component; and a body disposed in and at least
partially blocking said longitudinal passage whereby when said heat
shrinkable material is heated it will shrink onto said body thereby
at least partially restricting said passage and uncovering the air
permeable material to admit outside air into the article, wherein
said body is formed of a material impermeable to air and smoke.
2. A smoking article comprising: an elongated smoking article
component; a length of air permeable material wrapped about a
section of said component; a band of air impermeable, heat
shrinkable material disposed at least in part between said
component section and said air permeable material in position so as
normally to close the air permeable material against the passage of
air while at the same time leaving a longitudinal passage for smoke
through said component; and a body disposed in and at least
partially blocking said longitudinal passage whereby when said heat
shrinkable material is heated it will shrink onto said body thereby
at least partially restricting said passage and uncovering the air
permeable material to admit outside air into the article, wherein
said body is formed of a compressible filter material.
Description
This invention is concerned with improvements relating to smoking
articles, particularly filter and other cigarettes, and to filter
or mouthpiece components thereof.
An object of the invention is to provide means for effectively
reducing the delivery of particulate matter of tobacco smoke and/or
modifying the supply of air, especially in the last few puffs of a
cigarette.
According to the invention, a band or strip of a heat-shrink
material is wrapped around a filter and/or mouthpiece component
and/or a portion of a tobacco rod of a smoking article. Thus, a
filter component and/or the end of the tobacco rod of a cigarette
may be so wrapped with a strip of heat-shrink film material that,
when the cigarette is smoked and the burning coal approaches, hot
smoke from it will cause the said material to shrink, thereby
causing constriction and increasing the pressure drop to such an
extent that the passage of smoke will be substantially hindered or
even prevented. Since the delivery of total particulate matter, as
well as nicotine, on a per-puff basis normally increases rapidly
for the last few puffs, the use of the heat-shrink material will
reduce the delivery of total particulate matter.
The band or strip of heat-shrink material may additionally or
alternatively be arranged to control a supply of ventilating air
through a wrapping section of perforated or air-porous
material.
The accompanying diagrammatic drawings illustrate several forms of
embodiment of the invention as applied to cigarettes. In the pairs
of figures, FIGS. 1 and 2, FIGS. 3 and 4 and so forth, through
FIGS. 17 and 18, the first and second figures of each pair are
longitudinal sections through part, near the mouth end, of a
cigarette before and after smoking, respectively.
In the embodiment of FIGS. 1 and 2, a cigarette comprising tobacco
1 in a paper wrapping 2 is encircled at or near the mouth end by a
narrow band or strip 3 of heat-shrink film material. This band is
secured to the wrapping 2 by adhesive, for instance at narrow end
zones 4 and 5. On smoking the cigarette, when the burning coal
approaches the band 3, the latter will shrink as it is heated by
hot smoke from the coal, so that the circumference of the end of
the cigarette will be reduced (FIG. 2) and the pressure drop
increased to such an extent that the cigarette becomes difficult to
draw or even incapable of being smoked beyond this stage.
The cigarette of FIGS. 3 and 4 has a filter section or plug 6
enclosed in a wrap 7 which is encircled in turn by a band 8 of
heat-shrink material. The assembly 6-8 is connected to the
cigarette wrapping 2 in known manner by paper tipping 9. The band 8
is secured to the wrap 7 by adhesive at narrow end zones at 10 and
11 and the tipping 9 is similarly secured to the band 8 and to the
wrapping 2 at end zones at 11 and 12 respectively. The filter
section 6, which may be of slightly larger diameter than the
tobacco rod 1, is composed of fibrous material or open-cell foam
material, for example plasticised or unplasticised cellulose
acetate, viscose, paper or flocculated filter material, or
polyurethane or polyethylene foam material. In this case, when the
band 8 shrinks on being heated by the hot smoke from the
approaching coal, it will compress the material of the filter
section 6 adjacent to the tobacco (FIG. 4). The pressure drop will
thereby be increased to such an extent that the passage of smoke is
greatly hindered. With a dual or multiple filter, the arrangement
of FIGS. 3 and 4 may be applied to the filter section adjacent to
the tobacco rod.
In the embodiment of FIGS. 5 and 6, a body 13 of material
impermeable to air and smoke and of slightly smaller diameter than
the filter section 6 is interposed between the latter and the
tobacco 1. A band 14 of heat-shrink material located under the
tipping 9 is connected at end zones 15, 16 to the wrapping 2 and
filter wrap 7 respectively, an annular gap 13a being left between
the said band and the body 13. When heated by the hot smoke, the
band 14 will shrink onto the impermeable body 13, thereby closing
the gap 13a (FIG. 6). In effect, the filter is completely blocked
and further puffs can no longer be taken. The body 14 may be made
of wax, closed-cell plastic foam or other impermeable material. As
shown, it is spherical, but it may be of cylindrical or disc
form.
In the cigarette of FIGS. 7 and 8, perforations 17, for example two
or three rings of perforations, are provided in the tipping 9 where
it overlies a band 18 of heat-shrink material secured at 15 to the
wrapping 2. An impermeable body 13, in this case of cylindrical
form, is again interposed between the tobacco 1 and filter section
6. When the band 18 is heated and shrinks onto the impermeable body
13, closing the gap 13a between the band 18 and body 13, the holes
17 will be uncovered, thus replacing the smoke by air (FIG. 8).
With a similar arrangement, however, either the effect of reducing
or cutting off the smoke or the effect of replacing the smoke by,
or diluting it with, air can be achieved.
Perforations may be similarly provided in other embodiments of the
invention. For example, with the embodiment of FIGS. 3 and 4, rings
of perforations may be provided at 17a (FIG. 4) in the tipping 9
where they will be closed by the band 8 until the latter shrinks.
As shown in FIGS. 9 and 10, perforations at 17b in the tipping 9
may be similarly uncovered (FIG. 10) by the shrinkage of a band 20
of heat-shrink material encircling the end of the wrapped tobacco
rod 1. If smoke replacement or dilution is not required, however,
the arrangement of FIGS. 9 and 10 may be used without the
perforations at 17b.
FIGS. 11 and 12 illustrate a further arrangement in which
smoke-dilution or ventilation is provided. Interposed between the
filter section 6, which may be of conventional filter material, and
the tobacco rod 1 there is a further filter section 21, preferably
of material of softer consistency. This is encircled by a band 22
of heat-shrink material which over-wraps 2-3 mm onto the tobacco
rod. The tipping 9 has rings of perforations at 17c which are
closed by the band 22 until it shrinks (FIG. 12), compressing the
filter section 21. Thus, at the same time as air is admitted
through the perforations at 17c, the resistance to smoke flow
through the filter section 21 is increased. If desired, however,
provision may be made for the smoke to by-pass the compressed
filter section, although it is still diluted. An arrangement
similar to that illustrated may be used with a triple filter, in
which case the heat-shrink band may be arranged to compress the
tobacco-end section or middle section. With such arrangements, the
whole filter assembly may be additionally wrapped in porous
paper.
Instead of providing perforations in the tipping wrap 9, a wrap
section of porous paper may be employed.
The invention can also be applied to filter devices of the kind in
which a filtering diaphragm, particularly a tubular such diaphragm,
extends substantially axially of the filter, the heat-shrink
material being arranged to produce eventual closure or constriction
of the smoke path through the filter. In the filter device of this
kind shown in FIGS. 13 and 14, a cylindrical sleeve 23 of
heat-shrink material is fitted loosely and with a gap 23a around
the central tube 24, of porous filter paper, of a tubular filter.
Alternatively, the sleeve 23 may hang over the tube 24 and may be
held to the latter by a line of adhesive where it rests thereon.
The tube 24 is mounted in a non-permeable container or mouthpiece
25. The tube 24 is closed by a cap 26 at the end towards the
tobacco rod 1, but is open at the other end, while the container 25
is open at the former end and closed at the latter end. Smoke
normally passes through the filter in the manner indicated by
arrows in FIG. 13. When heated by hot smoke from the approaching
coal, however, the sleeve 23 will shrink onto the tube 24 (FIG. 14)
hindering or completely blocking the passage of smoke. The paper
tube 24 may be replaced by a tube of non-permeable material
containing perforations.
Alternatively, with a diaphragm type of filter device, the
heat-shrink material may be arranged to effect closure or
constriction of the entry to the space on the upstream side of the
diaphragm or of the exit from the said device or of some
intermediate part thereof.
The arrangement shown in FIGS. 15 and 16 is similar to that of
FIGS. 5 and 6, except that the body 13' of impermeable material, in
this case a cylindrical body, is interposed between two filter
sections 6 and 6', the diameter of the said body being slightly
less than that of the said sections. The band 14' of heat-shrink
material is secured to the sections 6 and 6' by adhesive at zones
27 and 28 respectively. The tipping 9 is secured at zones 27 and
29. When the band 14' shrinks (FIG. 16) it will close the gap 13a
and block the smoke path. A similar arrangement may be provided
between a filter and a mouthpiece.
The arrangement of FIGS. 17 and 18 is similar to that of FIGS. 3
and 4, with the exception that the band 8 of heat-shrink material
is extended over the end of the tobacco rod 1 to the wrapping 2 of
which it is secured by adhesive at a narrow zone 30. When the band
8' shrinks, the end of the tobacco rod 1 will be compressed (FIG.
18) as well as the adjacent part of the filter section 6.
Suitable heat-shrink film materials which may be employed are
polyvinylidene chloride, polypropylene, polyester and polystyrene
materials, but a polyvinyl chloride or polyethylene material is
preferably used. The extent of shrinkage will depend upon the
specification and conditions of use of the film material, such as
shrink temperature, energy, degree and thickness. It may also be
affected in some cases by the nature of the filter material used.
The butt length left when blocking or partial blocking of the
cigarette or filter occurs will depend on the film material,
particularly on its shrinkage temperature.
Preferably, a film material is used which will give unidirectional
shrinkage, this being applied in the circumferential direction.
However, a material with shrinkage in the longitudinal as well as
the transverse direction may be employed.
Coloured heat-shrink film material may be employed for the sake of
attractive appearance, especially in the case of ventilated filter
cigarettes.
For producing the tubular bands of heat-shrink film material, it is
necessary to seal overlapping edges of the material together to
produce a longitudinal joint. This sealing may have to be performed
during the production of a filter rod. The sealing can be simply
performed by applying a solvent for the material to the said edges,
folding the edges together and subjecting them to gentle heat. The
solvent may be applied by conventional techniques such as a wick or
a pasting wheel. Ketone-type solvents, such as methyl ethyl ketone,
methyl isobutyl ketone, acetone and cyclohexanone, the last
together with tetrahydrofurane, or an alcohol, for instance
tetrahydrofurfuryl alcohol, may be used. A thickening agent, such
as a cellulose derivative, may be added to the solvent. Adhesives
known for joining polyvinyl-chloride film may also be used.
Examples illustrating results obtainable by the use of the
invention will now be given.
EXAMPLE 1
A filter section 15 mm long composed of cellulose acetate and
wrapped in the manner shown in FIG. 3 (without perforations at 17a)
in a band of heat-shrink film material of the polyvinyl chloride
type supplied by the Goodyear Tyre and Rubber Co. under the
designation VITAFILM was attached to a cigarette and machine smoked
under standard conditions of 1 puff per minute of 35 ml volume and
2 seconds duration. The pressure drop of the filter increased from
6 cm water gauge before shrinkage of the band to 20 cm after
shrinkage.
EXAMPLE 2
The pressure drop of a 15 mm long filter section composed of paper
and similarly wrapped increased from 6 cm to 15 cm water gauge.
EXAMPLE 3
A triple filter composed of a 7 mm long section of closed-cell
polyethylene foam between a 6 mm long section of cellulose acetate
at the tobacco end and a 7 mm long section of cellulose acetate was
wrapped, in the manner shown in FIG. 15, in the heat-shrink
material referred to in Example 1, the foam section being of
slightly smaller diameter than the others. Initially the filter had
a pressure drop of 4 cm water gauge, but it was found to become
completely blocked on shrinkage of the wrapper.
EXAMPLE 4
In an arrangement generally similar to that of FIG. 1, a cigarette
was provided at a distance of 8 mm from the mouth-end with an
encircling band, 5 mm wide, of the aforesaid heat-shrink material.
On smoking the cigarette under standard conditions, the pressure
drop of the rod increased from 8 cm to 22 cm water gauge after the
cigarette had been puffed 6 or 7 times. A comparable normal-length
cigarette takes about 10 puffs to smoke.
EXAMPLE 5
A filter cigarette was produced with a 15 mm long filter section
composed of cellulose acetate of 1.6/48,000 denier which was
wrapped, in the manner shown in FIG. 17, in a band of heat-shrink
film material of the polyvinyl chloride type supplied by W.R. Grace
Ltd. under the designation "CRYOVAC VPMX." The material extended
over the tobacco rod to a distance of 5 mm. The pressure drop of
this cigarette increased, on smoking, from 13 cm before shrinkage
of the said material to 59.5 cm water gauge after shrinkage
thereof. The cigarette would have been discarded by a smoker after
about 9 puffs and at a pressure drop exceeding 25 cm. The decrease
in the delivery of total particulate matter (TPM) was about 34
percent.
EXAMPLE 6
With a cigarette similar to that of Example 5 but having a 15 mm
filter section of cellulose acetate of 15/64,000 denier, the
pressure drop increased from 8.2 to 45.5 cm water gauge.
EXAMPLE 7
A 15 mm filter section composed of viscose fibres and wrapped as in
FIG. 3 (without perforations at 17a) in a band of the heat shrink
material referred to in Example 1 was attached to a cigarette and
smoked under the standard conditions. The pressure drop of the
filter increased from 3 cm to 15 cm water gauge.
EXAMPLE 8
A dual filter composed of a 10 mm section of cellulose acetate and
a 5 mm section of closed-cell polyethylene foam material was
attached to a cigarette, with the section of foam material adjacent
to the tobacco, generally as in FIG. 7 (without perforations at
17). A band of the heat-shrink material referred to in Example 5
was wrapped around the 5 mm section and overlapped the tobacco rod
by 5 mm. the circumference of the closed-cell foam section was 1 mm
smaller than that of the cigarette. The pressure drop of the filter
was initially 12 cm water gauge. On smoking the cigarette under the
standard conditions, the filter was found to become completely
blocked after about 7 puffs. The TPM was reduced to about 50
percent in relation to a comparable, normal filter cigarette smoked
to an 8 mm butt.
EXAMPLE 9
A 15 mm filter section of cellulose acetate was wrapped in a band
of heat-shrink film material of the polyvinyl chloride type
supplied under the designation "Spicer Cowan BS2" and was attached
to a cigarette, generally as shown in FIGS. 3 and 4, with a tipping
paper provided (as at 17a in FIG. 4) with two rings of perforations
at 2.5 and 4.5 mm from the tobacco end of the filter. The
perforations were square, each having an area of 0.084 mm.sup.2,
and there were 33 perforations in each ring. On smoking the
cigarette through this filter under the standard conditions, the
TPM delivery was found to be reduced from 25 mg to 14 mg as
compared with a similar filter cigarette, but without the
heat-shrink band.
EXAMPLE 10
In an arrangement generally as shown in FIG. 11, but with porous
tipping paper, instead of the tipping 9 with perforations at 17c, a
dual filter composed of a 5 mm section and a 10 mm section of
cellulose acetate was attached to a cigarette with the 5 mm section
adjacent to the tobacco rod. The 5 mm section was wrapped with a
band of the heat-shrink material referred to in Example 5, which
also extended 5 mm over the tobacco rod. A tipping paper having a
porosity of 13,600 cm.sup.2 /minute/10 cm.sup.2 /10 cm water gauge
was used for assembly of the filter in known manner. On smoking the
cigarette through this filter under the standard conditions, the
TPM was reduced from 38 mg to 23.4 mg as compared with a cigarette
having a similar filter used in the normal manner.
EXAMPLE 11
A cigarette was provided with a filter similar to that of Example
10 except that the 5 mm section wrapped in the heat-shrink band was
a body of smaller diameter than the other section and made of
impermeable material as described with reference to FIG. 7. This
body was composed of closed-cell polyethylene foam material and the
tipping paper was perforated over the part encircling the said
body. On smoking the cigarette, the TPM was found to be reduced
from 38 mg to 25 mg as compared with a cigarette having a similar
filter used in the normal manner.
EXAMPLE 12
With a filter-cigarette arrangement such as is shown in FIG. 9
(without perforations at 17b), a 5 mm length of the tobacco rod 1
was wrapped in a band of polyvinyl chloride, heat-shrink material.
With this provision, the pressure drop was found to increase from
11 cm to 33 cm water gauge on smoking the cigarette under standard
conditions.
EXAMPLE 13
In a filter device such as is shown in FIG. 13, the sleeve of
heat-shrink material had a diameter 1-2 mm larger than that of the
central paper tube. On smoking a cigarette through this device,
whose pressure drop was initially 13 cm water gauge, the filter
became completely blocked on shrinkage of the material.
* * * * *