U.S. patent application number 13/636740 was filed with the patent office on 2013-05-02 for perforated cigarette paper.
This patent application is currently assigned to DELFORTGROUP AG. The applicant listed for this patent is Bernhard Eitzinger. Invention is credited to Bernhard Eitzinger.
Application Number | 20130104915 13/636740 |
Document ID | / |
Family ID | 44237178 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130104915 |
Kind Code |
A1 |
Eitzinger; Bernhard |
May 2, 2013 |
Perforated Cigarette Paper
Abstract
The invention relates to cigarette paper (1) providing
self-extinguishing properties to a cigarette made therefrom,
wherein the cigarette paper comprises at least one discrete region
(2) that is perforated and comprises a permeability to air that is
greater than the permeability to air outside of the perforated
region. The perforated region is preferably present in a finished
filter cigarette in the vicinity of the filter (5).
Inventors: |
Eitzinger; Bernhard;
(Gmunden, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eitzinger; Bernhard |
Gmunden |
|
AT |
|
|
Assignee: |
DELFORTGROUP AG
Traun
AT
|
Family ID: |
44237178 |
Appl. No.: |
13/636740 |
Filed: |
March 30, 2011 |
PCT Filed: |
March 30, 2011 |
PCT NO: |
PCT/EP2011/001602 |
371 Date: |
October 23, 2012 |
Current U.S.
Class: |
131/281 ;
131/280; 131/331; 131/365 |
Current CPC
Class: |
A24D 1/10 20130101; A24D
1/027 20130101 |
Class at
Publication: |
131/281 ;
131/365; 131/331; 131/280 |
International
Class: |
A24D 1/10 20060101
A24D001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 1, 2010 |
DE |
10 2010 013 669.7 |
Claims
1. A cigarette paper that provides a cigarette manufactured
therefrom with self-extinguishing properties, wherein the base
paper has a CO.sub.2 diffusivity of less than 0.35 cm/s and the
cigarette paper comprises at least one discrete area, wherein this
area is perforated and has an air permeability greater than the air
permeability beyond the perforated area.
2. The cigarette paper according to claim 1, wherein the air
permeability within the perforated area is constant over the entire
perforated area.
3. The cigarette paper according to claim 1, wherein the air
permeability within the perforated area is from 50 CU to 2000
CU.
4. The cigarette paper according to claim 1, wherein the air
permeability within the perforated area is from 100 CU to 1000
CU.
5. The cigarette paper according to claim 1, wherein the width of
the perforated area is between 2 mm and 25 mm.
6. The cigarette paper according to claim 1, wherein the width of
the perforated is between 4 mm and 12 mm.
7. The cigarette paper according to claim 1, wherein the width of
the perforated is between 5 mm and 9 mm.
8. The cigarette paper according to claim 1, further comprising a
short side A for facing a filter in the finished cigarette, wherein
the perforated area is within the third of the cigarette paper
length adjacent to the short side A, preferably within the quarter
of the cigarette paper length adjacent to the short side A, and
more preferably within the fifth of the cigarette paper length
adjacent to the short side A.
9. The cigarette paper according to claim 1, further comprising a
short side A for facing a filter of the finished cigarette, wherein
the mean air permeability within the half or third of the length of
the cigarette paper adjacent to short side A is greater than the
mean air permeability of the remaining part of the cigarette
paper.
10. The cigarette paper according to claim 1, comprising at least a
second discrete area that is perforated and separated from the
first perforated area by a non-perforated area.
11. The cigarette paper according to claim 10, further comprising a
short side A for facing a filter of the finished cigarette, wherein
the second perforated area is located further away from the short
side A than the first perforated area.
12. The cigarette paper according to claim 10, wherein the air
permeability within the second perforated area is lower than the
air permeability within the first perforated area.
13. The cigarette paper according to claim 10, comprising at least
one further discrete area that is perforated and separated from the
first perforated area and from the second perforated area by at
least one non-perforated area.
14. The cigarette paper according to claim 13, further comprising a
short side A for facing a filter of the finished cigarette, wherein
the further perforated area is located further away from the short
side A than the first perforated area and the second perforated
area.
15. The cigarette paper according to claim 13, wherein the air
permeability within the further perforated area is lower than the
air permeability within the first perforated area and the second
perforated area.
16. The cigarette paper according to claim 1, wherein the air
permeability beyond a perforated area is less than 15 CU.
17. The cigarette paper according to claim 1, wherein the air
permeability beyond a perforated area is less than 10 CU.
18. The cigarette paper according to claim 1, having a mean CO2
diffusivity of less than 0.25 cm/s.
19. The cigarette paper according to claim 1, having a mean CO2
diffusivity of less than 0.20 cm/s.
20. A cigarette comprising a cigarette paper according to claim 1
and furthermore comprising a filter and a tipping paper, wherein
the distance between the tipping paper and the first perforated
area is less than 10 mm.
21. The cigarette of claim 20, wherein the distance between the
tipping paper and the first perforated area is less than 5 mm.
22. A method for producing a cigarette paper according to claim 1,
comprising a perforation step to create at least one perforated
area by at least one of electrostatic perforation, laser
perforation, and mechanical perforation.
23. The method according to claim 22, wherein the perforation step
is carried out on a cigarette machine or on a device separated from
the cigarette machine.
24. Use of a paper to produce a cigarette paper according to claim
1, wherein the paper is provided in the form of a paper web having
a width of 0.3 m to 5 m or of 9 mm to 35 mm.
25. Use of a cigarette paper according to claim 1 to produce a
cigarette according to claim 20.
Description
TECHNICAL FIELD
[0001] The present invention relates to a cigarette paper that
provides a cigarette manufactured therefrom with self-extinguishing
properties and has at least one discrete perforated area.
BACKGROUND ART
[0002] Due to legal regulations regarding the self-extinguishment
of cigarettes, there is a need within the cigarette industry to
provide cigarettes which ensure this self-extinguishment.
Smoldering cigarettes left unattended are thus to be prevented from
igniting furniture, beds or other home textiles. It is thus sought
to produce cigarettes which have a reduced tendency to ignite other
materials if the smoldering cigarette comes into contact with these
materials.
[0003] A test to determine the ignition tendency of cigarettes is
described in ASTM E2187-04b. The test consists of placing a
smoldering cigarette on a substrate consisting of 10 layers of a
filter paper. The test is performed on 40 cigarettes and the
percentage of the cigarettes which self-extinguish on the substrate
before the glowing cone reaches the cigarette filter is
determined.
[0004] Within the scope of the invention, the self-extinguishing
property can be understood for example to mean that at least the
majority of the cigarettes tested according to ASTM
E2187-04bfulfill the aforesaid criterion, that is to say the
percentage is above 50%.
[0005] A typical cigarette consists of tobacco, which is enwrapped
by a cigarette paper and together therewith forms a typically
cylindrical tobacco rod. The tobacco rod is usually adjoined by the
filter, which consists typically of cellulose acetate fibers. The
filter and the tobacco rod are enwrapped by the tipping paper. The
tipping paper connects the filter to the tobacco rod.
[0006] The self-extinguishment of a cigarette is in most cases
achieved by corresponding design of the cigarette paper, that is to
say of the paper enwrapping the tobacco. The cigarette paper is
designed such that the diffusion constant is so low, at least in
some areas of the cigarette paper, that insufficient oxygen to
maintain the smoldering process reaches the glowing cone. As a
consequence, the smoldering cigarette self-extinguishes.
[0007] Typical cigarette papers consist of cellulose fibers,
obtained from wood, flax or other materials. Mixtures of cellulose
fibers of different origin can also be utilized. Cigarette papers
have a typical basis weight of 10 g/m.sup.2 to 60 g/m.sup.2,
wherein the range of 20 g/m.sup.2 to 35 g/m.sup.2 is generally
preferred.
[0008] Cigarette papers often also comprise inorganic, mineral
fillers, which are added to the paper in a mass fraction of 10% to
40%. A frequently used filler material is chalk (calcium
carbonate), but other oxides and carbonates, such as magnesium
oxide and aluminum hydroxide, can also be utilized.
[0009] Cigarette paper can also be equipped with burning salts,
which increase or reduce the burn rate of the paper. Sodium citrate
and tripotassium citrate as well as mixtures thereof are used very
frequently and are added to the paper in an amount of 0% to 5% of
the paper mass. The group of burning salts of technical relevance
additionally comprises citrates, malates, tartrates, acetates,
nitrates, succinates, fumarates, gluconates, glycolates, lactates,
oxalates, salicylates, .alpha.-hydroxycaprylates and phosphates,
however.
[0010] Cigarette papers are typically produced in rolls having a
width between 0.3 m to 5 m and for example a recut into bobbins
having a width, derived from the cigarette circumference, typically
of 9 mm to 35 mm.
[0011] One possible method to obtain self-extinguishment is to
choose a cigarette paper of which the diffusion constant is already
so low as a result of the paper production process that the
cigarette extinguishes by itself. As a consequence however, the
flow of air into the cigarette, that is to say the air
permeability, is highly reduced due to a pressure difference. This
has proven to be disadvantageous, since the smoke in the tobacco
rod of the cigarette can only be diluted to a very small extent by
the inflowing air during the smoking process and the cigarette
smoke values for tar, nicotine and especially carbon monoxide are
increased considerably. For example, the air permeability of such
papers is less than 10 CORESTA Units (1 CORESTA Unit=1 CU=1
cm.sup.3/(cm.sup.3 min kPa)), whereas typical cigarette papers,
which are not self-extinguishing, have an air permeability between
20 CU and 300 CU.
[0012] This disadvantage is eliminated by perforating the cigarette
paper over its entire surface. Large holes compared to the natural
pore structure are thus created in the paper and increase the air
permeability, but cause little change to the diffusion constant of
the paper. A diluting airflow into the cigarette during the smoking
process is thus enabled and the cigarette smoke values are lowered
without impairing the self-extinguishment of cigarettes
manufactured from this paper in the above-mentioned test.
[0013] This perforation can be carried out by different methods.
For example, electrostatic perforation is used, in which the paper
is transported through one or more spark discharge gaps, which burn
holes into the paper. These holes typically have a diameter between
5 .mu.m and 100 .mu.m. Furthermore, laser perforation can be used,
which generates slightly larger holes having a typical diameter
between 50 .mu.m and 500 p.m. A further example is mechanical
perforation, in which needles or similar tools produce holes in the
paper. These holes have a typical diameter between 100 .mu.m and
2000 .mu.m.
[0014] The air permeability achieved with the perforation methods
can be very high, for example up to more than 6000 CU, although the
cigarette papers are generally perforated such that the air
permeability after the perforation is between 50 CU and 500 CU.
[0015] The perforation process can be performed after paper
production on separate, dedicated perforation machines in roll or
bobbin width. Of course, perforation on the cigarette machine is
also possible, that is to say before, during or after the
production of cigarettes or similar tobacco products from the
cigarette paper on the cigarette machine, by any desired
perforation method.
[0016] Perforation of a cigarette paper over the entire surface
thereof, said cigarette paper having low initial air permeability,
has a significant disadvantage however in the smoker's acceptance
of a cigarette manufactured from this paper. Because of the high
air permeability, a lot of diluting air flows into the cigarette
during the smoking process. The tobacco rod and therefore also the
perforated cigarette paper are then consumed during the smoking
process. The area through which the diluting air can flow into the
cigarette is thus reduced with every puff taken by the smoker on
the smoldering cigarette as well as during the smoldering process.
This causes the smoker to receive an amount of tar, nicotine and
carbon monoxide that increases with each puff as the tobacco rod
becomes accordingly shorter. He thus feels that the cigarette is
getting "stronger" with each puff. This sensation is
undesirable.
[0017] One possibility to compensate for this effect is not to
choose constant air permeability over the length of the tobacco
rod, but instead to provide a continuous air permeability profile
along the cigarette shaft by perforation of the cigarette profile
so that during the smoking process the increase in the cigarette
smoke values with each puff is reduced to the greatest possible
extent. A repeated continuous air permeability profile is therefore
to be produced over the cigarette paper web by perforation.
[0018] Although this method is theoretically possible, substantial
technical problems arise. On the one hand the regulation of the
perforation device for producing such a continuous profile is very
demanding and the continuous measurement of the air permeability
for the regulation can only be carried out imprecisely and is not
feasible at high speed. The speed at which such profiles can be
produced, if at all possible, is also accordingly low.
[0019] On the other hand, the endless tobacco rod formed from the
cigarette paper on the cigarette machine has to be cut precisely at
the beginning and at the end of such a continuous air permeability
profile, so that the air permeability profile is in the correct
position on the finished cigarette. The beginning of the profile
can only be detected very imprecisely however, if at all, due to
the continuous progression of the air permeability.
[0020] The object of the present invention is therefore to overcome
the disadvantages of the prior art.
SUMMARY
[0021] The object of the invention is achieved by a cigarette paper
that provides a cigarette manufactured therefrom with
self-extinguishing properties, wherein the cigarette paper
comprises at least a first discrete area, which is perforated and
has an air permeability greater than the air permeability beyond
the first perforated area.
[0022] In one embodiment of the cigarette paper, the air
permeability within the first perforated area is constant over the
entire perforated area.
[0023] In one embodiment of the cigarette paper, the air
permeability within the first perforated area is from 50 CU to 2000
CU, preferably from 100 CU to 1000 CU.
[0024] In one embodiment of the cigarette paper, the width of the
first perforated area is between 2 mm and 25 mm, preferably between
4 mm and 12 mm, more preferably between 5 mm and 9 mm.
[0025] In one embodiment, the cigarette paper further comprises a
short side A, which is intended to face a filter in the finished
cigarette, wherein the first perforated area is located within the
third of the cigarette paper length adjacent to the short side A,
preferably within the quarter of the cigarette paper length
adjacent to the short side A, and more preferably within the fifth
of the cigarette paper length adjacent to the short side A.
[0026] In one embodiment, the cigarette paper further comprises a
short side A, which is intended to face a filter (6) in the
finished cigarette, wherein the mean air permeability within the
half or third of the cigarette paper length adjacent to the short
side A is greater than the mean air permeability of the remaining
part of the cigarette paper.
[0027] In one embodiment, the cigarette paper comprises at least a
second discrete area, which is perforated and separated from the
first perforated area by a non-perforated area. In one embodiment
of the cigarette paper, the second perforated area is further away
from the first short side than the first perforated area.
[0028] In one embodiment of the cigarette paper, the air
permeability within the second perforated area is lower than the
air permeability within the first perforated area.
[0029] In one embodiment, the cigarette paper comprises at least
one further discrete area, which is perforated and is separated
from the first perforated area and the second perforated area by at
least one non-perforated area.
[0030] In one embodiment of the cigarette paper, the further
perforated area is located further away from the short side A than
the first perforated area and the second perforated area.
[0031] In one embodiment of the cigarette paper, the air
permeability within the further perforated area is lower than the
air permeability within the first perforated area and the second
perforated area.
[0032] In one embodiment of the cigarette paper, the air
permeability within the second perforated area and/or the further
perforated area is constant over the respective entire perforated
area.
[0033] In one embodiment of the cigarette paper, the air
permeability within the second perforated area and/or the further
perforated area is from 50 CU to 2000 CU, preferably from 100 CU to
1000 CU.
[0034] In one embodiment of the cigarette paper, the width of the
second perforated area and/or of the further perforated area is
between 2 mm to 25 mm, preferably between 4 mm and 12 mm, and more
preferably between 5 mm and 9 mm.
[0035] In one embodiment of the cigarette paper, the air
permeability beyond a perforated area is less than 15 CU,
preferably less than 10 CU.
[0036] In one embodiment, the diffusivity of the cigarette paper
(beyond and within a perforated area) or the mean diffusivity of
the cigarette paper is less than 0.35 cm/s, preferably less than
0.25 cm/s, and more preferably less than 0.20 cm/s.
[0037] In one embodiment, the cigarette paper comprises one or more
mineral fillers, selected from the group consisting of carbonates
and oxides, preferably from the group consisting of calcium
carbonate, aluminum hydroxide and magnesium oxide, and the weight
fraction of the one or more mineral fillers is particularly
preferably from 10% to 40%.
[0038] In one embodiment, the cigarette paper comprises one or more
burning salts, selected from the group consisting of citrates,
malates, tartrates, acetates, nitrates, succinates, fumarates,
gluconates, glycolates, lactates, oxalates, salicylates,
.mu.-hydroxycaprylates and phosphates, preferably selected from the
group consisting of sodium-citrate and tripotassiumcitrate, and the
content of the one or more burning salts is particularly preferably
up to 5% by weight.
[0039] In one embodiment, the cigarette paper has a basis weight of
10 g/m.sup.2 to 60 g/m.sup.2, preferably of 20 g/m.sup.2 to 35
g/m.sup.2.
[0040] The object of the present invention is furthermore achieved
by a filter cigarette, comprising a cigarette paper according to
the present invention and furthermore comprising a filter and a
tipping paper, wherein the distance between the tipping paper and
the first perforated area is less than 10 mm, preferably less than
5 mm.
[0041] The object of the present invention is furthermore achieved
by a method for producing a cigarette paper according to the
present invention, said method comprising a perforation step to
create at least one perforated area by electrostatic perforation,
laser perforation and/or mechanical perforation.
[0042] In one embodiment of the method, the perforation step is
carried out on a cigarette machine or alternatively on a device
separate from the cigarette machine.
[0043] The object of the present invention is furthermore achieved
by the use of a paper (base paper) to produce a cigarette paper
according to the present invention, preferably by a method
according to the present invention, wherein the paper is provided
in the form of a paper web having a width of 0.3 m to 5 m or
alternatively of 9 mm to 35 mm.
[0044] In one embodiment of the use, the air permeability of the
base paper is less than 15 CU, preferably less than 10 CU.
[0045] In one embodiment of the use, the base paper has a
diffusivity of less than 0.35 cm/s, preferably of less than 0.25
cm/s, most preferably of less than 0.20 cm/s.
[0046] In one embodiment of the use, the base paper comprises a
mineral filler selected from the group consisting of carbonates and
oxides, preferably selected from the group consisting of calcium
carbonate, aluminum hydroxide and magnesium oxide, and the weight
fraction of the one or more mineral fillers is particularly
preferably from 10% to 40%.
[0047] In one embodiment of the use, the base paper comprises one
or more burning salts selected from the group consisting of
citrates, malates, tartrates, acetates, nitrates, succinates,
fumarates, gluconates, glycolates, lactates, oxalates, salicylates,
.alpha.-hydroxycaprylates and phosphates, preferably selected from
the group consisting of sodium citrate and tripotassium citrate,
and the content of the one or more burning salts is particularly
preferably up to 5% by weight.
[0048] In one embodiment of the use, the base paper has a basis
weight of 10 g/m.sup.2 to 60 g/m.sup.2, preferably of 20 g/m.sup.2
to 35 g/m.sup.2.
[0049] The object of the present invention is furthermore achieved
by use of a cigarette paper according to the present invention to
produce a cigarette according the present invention.
[0050] The present invention is based on the fact that it has
surprisingly been found that it is not necessary to produce a
continuous air permeability profile but that it is instead
sufficient to perforate, over the cigarette paper, a discrete area
with constant air permeability arranged close to the cigarette
filter to achieve a comparably good effect.
[0051] If one discrete perforated area close to the filter is
insufficient, because the cigarette smoke values are still too
high, further discrete areas with different air permeability can of
course be produced by perforation and are then located accordingly
closer to the end of the cigarette to be lit. Two such discrete
perforated areas are often sufficient.
[0052] If two or more discrete perforated areas--viewed in
longitudinal direction of a cigarette to be produced from this
paper--are arranged in succession, there is still preferably a
tendency to increase the air permeability in the direction towards
the mouthpiece, that is to say the end opposite the end to be lit.
For example, the mean air permeability in the half or third of the
cigarette paper closer to the mouthpiece is preferably higher than
in the remaining part of the cigarette paper.
[0053] Although the cause of this effect is not fully known, the
following explanation may give an indication as to how it is
achieved. During the smoking process, a negative pressure with
respect to the ambient air is produced at the mouth end of the
cigarette to cause an airflow through the cigarette and to
transport the smoke through the filter to the smoker. This negative
pressure decreases along the cigarette, so that approximately no
pressure difference exists between the point directly in front of
the glowing cone and the ambient air.
[0054] A discrete perforated area located close to the cigarette
filter is then situated in an area of the tobacco rod in which the
pressure difference between the ambient air and the inside of the
tobacco rod is high during the smoking process, that is to say a
comparably large amount of air can flow into the tobacco rod. In
areas closer to the glowing cone and further away from the mouth
end, this pressure difference is smaller. These areas therefore
contribute less to the air volume flowing into the cigarette and
there is little influence on the cigarette smoke values during a
puff if these areas are not perforated, that is to say have low air
permeability.
[0055] Since the perforated areas are discrete in nature and are
clearly separated from the non-perforated areas, they can be
clearly detected with optical sensors and it is not difficult to
synchronize the paper feed and the cutting process on the cigarette
machine such that the discrete areas on each cigarette are situated
in the desired position close to the filter.
[0056] Additionally, the air permeability in each of the perforated
areas is constant. Therefore the perforation device just needs to
be switched on and off at a frequency corresponding to the speed of
the paper web. This is much easier than following a continuous air
permeability profile. Also, perforation of discrete areas with
different air permeability, which is constant within the region
however, causes no difficulties since the perforation power of the
perforation device can be adjusted easily each time said device is
switched on or off.
BRIEF DESCRIPTION OF THE DRAWINGS
[0057] FIG. 1 is a schematic illustration of a cigarette with an
exemplary embodiment of the cigarette paper 1 according to the
invention, comprising a first perforated area 2, a second
perforated area 3 and further perforated areas 4. In this
illustration, the cigarette paper 1 is partly unrolled from the
tobacco column 7 of the cigarette. A filter 6 and tipping paper 5
partially enwrapping it as well as a short side A are also
illustrated.
[0058] FIG. 2 shows the specific perforation pattern of the
cigarette paper to achieve the desired effect. This pattern results
from the typical production process of machine-made cigarettes. The
perforated areas of the wrapper, denoted by numbers, in FIG. 2
correspond to those of FIG. 1. When producing cigarettes, an
endless tobacco rod is first formed and is then cut along lines B
into pieces measuring double the length of the tobacco rod of a
cigarette. In a subsequent step of the cigarette production
process, this double-length part of the tobacco rod is cut into two
pieces along line C and separated in the axial direction so that a
double-length filter tip can be placed in between. The entire
double-length filter and sub-area of the tobacco rods adjacent to
the filter are adhered and wrapped with a double-width tipping
paper. After this, the double cigarette, connected by the double
length filter, is cut into two cigarettes by a final cut through
the middle of the filter. The pattern to be produced by perforation
on the cigarette paper can also be adapted to other methods of
cigarette production.
DETAILED DESCRIPTION
Example 1
[0059] Starting point of the examples is a cigarette paper having
the following specification:
TABLE-US-00001 Basis weight 28 g/m.sup.2 Filler fraction 21% of the
paper mass Filler chalk Burning salt fraction 1% Burning salt
potassium citrate Air permeability 6 CU Diffusivity 0.2 cm/s (for
CO.sub.2)
[0060] The diffusivity is the diffusion constant of the paper
[cm.sup.2/s] divided by the thickness of the paper [cm]. It is a
transfer coefficient and describes the gas flow through the paper
at a given concentration difference independently of the thickness
of the paper. The diffusivity can be measured for example with a
CO.sub.2 diffusivity meter by Sodim.
[0061] Of course, equally good results can also be achieved with
other cigarette papers, for example with a different basis weight,
different fillers and filler fraction, different burning salts and
different burning salt fraction, as long as the air permeability
thereof before perforation correspondingly low, that is to say
typically less than approximately 15 CU, or the diffusion constant
thereof is less than approximately 0.35 cm/s, to ensure the
self-extinguishment of the cigarettes manufactured therefrom.
[0062] This cigarette paper was then perforated electrostatically
over its entire surface, so that an air permeability of 50 CU, 100
CU, 150 CU and 200 CU was achieved.
[0063] Further paper samples were prepared from the same cigarette
paper, in which discrete areas were perforated instead of the
entire surface. These areas were designed as bands, so that the
perforated area had a defined width but enclosed the cigarette
entirely in the circumferential direction. The papers were equipped
with one or two bands, although there is no reason why more bands
cannot also be provided, however. The specifications of these
papers are listed in Table 1:
TABLE-US-00002 TABLE 1 Specifications of the paper samples Area 1
Area 2 Comparable air Distance* Width Air Permeability Distance*
Width Air Permeability permeability ** Sample [mm] [mm] [CU] [mm]
[mm] [CU] [CU] A 1 6 160 50 B 1 6 650 200 C 1 6 120 30 6 120 50 D 1
6 240 30 6 240 100 E 1 6 370 30 6 370 150 F 1 6 500 30 6 500 200 G
3 6 160 50 H 5 6 160 50 J 1 7 140 50 K 1 9 110 50 L 1 6 130 30 6 90
50 M 1 6 410 30 6 270 150 N 1 20 90 50 *The distance is the gap
from the front edge of the tipping paper to the beginning of the
discrete perforated area. ** The comparable air permeability is the
air permeability of the cigarette paper perforated over its entire
surface that provides the same cigarette smoke values on the test
cigarette as the cigarette paper perforated in discrete areas.
[0064] Cigarettes with the following specifications were
manufactured from all papers:
TABLE-US-00003 Cigarette length 84 mm Filter length 20 mm Length of
the tipping paper 24 mm Length of the tobacco rod 64 mm Length of
visible tobacco rod 60 mm Diameter 7.8 mm Tobacco weight 650 mg
Tobacco Blend American Blend Degree of filter ventilation 15%
These specifications are understood to be merely exemplary, and the
invention can of course be applied to any other cigarette design
with comparable success.
[0065] The ignition propensity of all cigarette samples was first
tested according to ASTM E2187-04b. In accordance with ASTM
E2187-04b, 40 cigarettes were tested per cigarette paper and 90% or
more of the tested cigarettes of all samples self-extinguished,
wherein no statistically significant differences between the
samples could be found.
[0066] The cigarettes were further smoked by the method presented
in DIN ISO 4387. With this method, a volume of 35 cm.sup.3 in 2
seconds is drawn at the mouth end of the smoldering cigarette every
minute. This drawing of 35 cm.sup.3 is called a puff. The procedure
is repeated until the cigarette is smoked below a minimum length
defined by the standard. The smoke is drawn through a glass fiber
filter, which is chemically analyzed later on. From this, the
nicotine-free dry condensate ("tar") and the nicotine are
determined and are usually given in units of mg per cigarette.
[0067] The machine smoking was carried out on a smoking machine of
the Borgwaldt RM20 type, which was modified however such that every
puff of the cigarette was passed through a different glass fiber
filter, so that the cigarette smoke values of each puff could be
determined after analysis. 20 cigarettes from each paper sample
were machine-smoked in this way.
[0068] Since the cigarette is lit at the first puff, the first puff
is an exception with respect to its cigarette smoke values and will
be excluded from the considerations. It is also possible during the
standardized, machine smoking that the last puff cannot be fully
carried out, because the cigarette falls below the prescribed
minimum length during the puff. Such a puff ("fractional puff") is
recorded as a fraction of a whole puff. To simplify the
presentation, the last puff is therefore also excluded from the
considerations.
[0069] Generally, there is a monotone increase of the cigarette
smoke values from puff to puff. To describe the non-uniformity of
the cigarette smoke values from puff to puff the ratio of the
nicotine-free condensate ("tar") between the penultimate puff and
the second puff of the cigarette is calculated. This ratio is
listed in Table 2. The higher this ratio, the stronger the
cigarette smoke values increase from puff to puff and the more
non-uniform is the puff profile.
TABLE-US-00004 TABLE 2 Non-uniformity of the cigarette smoke values
Penultimate Ratio of Tar: Reduction Sample second puff Comparative
Value*** |%| A 1.23 1.42 -13.4 B 1.65 2.08 -20.7 C 1.25 1.42 -12.0
D 1.36 1.55 -12.2 E 1.53 1.73 -11.6 F 1.72 2.08 -17.3 G 1.30 1.42
-8.4 H 1.35 1.42 -4.9 J 1.22 1.42 -14.1 K 1.25 1.42 -12.0 L 1.23
1.42 -13.4 M 1.47 1.73 -15.0 N 1.31 1.42 -7.7 ***The comparative
value is the ratio of tar between the penultimate and the second
puff for a cigarette with a cigarette paper perforated over the
entire surface and with the air permeability given in Table 1.
All samples show an improvement in the uniformity of the puff
profile, wherein typically a reduction of the observed tar ratios
of approximately 5% to 20% is achieved.
Example 2
Samples A and B
[0070] At first it can be seen that the concentration of the
perforation in discrete areas close to the filter allows a
reduction in the air permeability, since the perforated areas are
now located in a region in which the difference between the ambient
air pressure and the pressure within the tobacco rod during the
smoking process is higher than in regions located closer to the
glowing cone. The paper, which is perforated over the entire
surface, has an air permeability of 50 CU over a length of 60 mm,
whilst sample A is perforated only over a tenth of this length,
namely 6 mm. It would be expected that, to get the same airflow
into the cigarette, the air permeability needs to be 10 times as
high, that is to say 500 CU. Surprisingly, it can be seen that just
160 CU are sufficient to achieve the same cigarette smoke values.
Regarding the uniformity of the puff profile, an improvement in the
tar ratio of approximately 13% from 1.42 to 1.23 is achieved.
[0071] At higher air permeabilities (sample B), this effect becomes
even more pronounced. In this case too, an air permeability of 650
CU instead of a nominal value of 200.times.60/6=2000 CU is
sufficient.
Example 3
Samples C-F
[0072] If the cigarette paper is perforated in two discrete areas
instead of one discrete area, then cigarette smoke values
comparable to a cigarette with a cigarette paper perforated over
the entire surface can be achieved with even lower air
permeability. This is obvious, since the perforated surface area is
now twice as large compared to just one perforated area.
Theoretically, the air permeability of sample C could be chosen to
be half as much, that is to say 80 CU. However, the second
perforated area is located further away from the mouth end and
therefore in a region in which the pressure difference is no longer
as high. Moreover, it is consumed during the smoking process. Its
contribution is therefore smaller and hence both areas of sample C
needed to be perforated with 120 CU to obtain cigarette smoke
values comparable to those of a cigarette with a 50 CU paper
perforated over the entire surface. These considerations apply
accordingly at the higher air permeabilities of samples D, E and
F.
[0073] With regard to the ratio of the tar values, a distinct
improvement of approximately 10% to 20% compared to perforation
over the entire surface can be seen, though this improvement is not
as distinct as with just one perforated area.
[0074] Due to the lower air permeability, it is possible to carry
out perforation at lower power and higher speed, and therefore this
advantage has to be weighed against the reduced improvement in the
uniformity of the puff profile.
Example 4
Samples A, G and H
[0075] The samples A, G and H differ solely in the distance of the
perforated area from the front edge of the tipping paper. For
sample A it is 1 mm, for sample G it is 3 mm, and finally for
sample H it is 5 mm. It was found that an improvement in the
uniformity of the puff profile was achieved compared to the paper
perforated over the entire surface, but the extent of this
improvement decreases quickly if the first perforated area is too
far away from the front edge of the tipping paper. More
specifically, the improvement decreases from 13% to approximately
8% at 3 mm to just 5% at 5 mm distance. It is therefore preferred
to keep this distance at least smaller than 10 mm and preferably
smaller than 5 mm.
Example 5
Samples A, J, K and N and B
[0076] The samples A, J, K and N differ firstly in the width of the
perforated area. The air permeability was also adjusted accordingly
to obtain comparable cigarette smoke values. Sample A, with a width
of 6 mm, has 160 CU, sample J, with a width of 7 mm, has
approximately 140 CU, and sample K, with a width of 9 mm, has just
110 CU, and sample N, with a width of 20 mm, lastly has just 80
CU.
[0077] An improvement in the uniformity of the puff profile from 7%
to 14% could be achieved. This shows that the influence of the
width is rather small. It may be assumed that the perforated area
may also have a width of more than 20 mm if an improvement is to be
achieved. Based on this data, the maximum width of the perforated
area will be chosen to be approximately 25 mm.
[0078] The minimum width is limited by the maximum air permeability
that can be achieved by perforation devices in such a narrow region
without impairing the tensile strength of the paper too much.
Considering sample B, with 650 CU over a width of 6 mm as starting
point, then a 2 mm wide area must be perforated nominally to 1950
CU to get the same result. This is already a very high air
permeability that is difficult to achieve in such a small area,
which is why the width of the perforated area is to be between 2 mm
and 25 mm, preferably between 4 mm and 12 mm, and more preferably
between 5 mm and 9 mm.
Example 6
Sample A, E, L and M
[0079] Finally, samples L and M show that the air permeability of
the two perforated areas need not be the same. Based on the
previous results, it seems to be advantageous to perforate more
intensely the area located closer to the mouth end. For samples L
and M, the air permeability of the first area is approximately 150%
of the air permeability of the second area.
[0080] At approximately 13% (sample L), the achieved improvement in
the ratio of the tar values is comparable to a paper with a
perforated area from sample A.
[0081] At higher air permeability however, as in samples E and M,
it can be seen that, at -11.6%, the use of the same perforation
level in both areas (sample E, 370 CU) provides a result worse than
with the unequally perforated paper from sample M (410 CU/270 CU)
with a -15% change in the tar ratio.
[0082] In any case, it can be assumed from these results that it is
not advantageous to perforate the second area more intensely than
the first area. As far as it is technically expedient and
reconcilable with the cigarette smoke values, it is sought to
perforate the second area less intensely.
[0083] Similarly, for a plurality of perforated areas, it is true
that, viewed from the mouth end to the glowing cone, each area
should be perforated less intensely than its predecessor.
[0084] There is also no reason to provide the areas with different
widths. Likewise, the position of the perforated areas can also be
varied.
[0085] On the whole, many further variations of this invention are
conceivable and the examples here merely illustrate the principle
of the invention and are not intended to be limiting.
* * * * *