U.S. patent application number 15/515252 was filed with the patent office on 2017-11-23 for apparatus and method for manufacturing a wrapped endless rod of substantially flat continuous material.
The applicant listed for this patent is PHILIP MORRIS PRODUCTS S.A.. Invention is credited to Alberto BONICI, Daniele SANNA.
Application Number | 20170332694 15/515252 |
Document ID | / |
Family ID | 52130051 |
Filed Date | 2017-11-23 |
United States Patent
Application |
20170332694 |
Kind Code |
A1 |
SANNA; Daniele ; et
al. |
November 23, 2017 |
APPARATUS AND METHOD FOR MANUFACTURING A WRAPPED ENDLESS ROD OF
SUBSTANTIALLY FLAT CONTINUOUS MATERIAL
Abstract
The method for manufacturing a wrapped endless rod of
substantially flat continuous material comprises the steps of
providing a substantially flat continuous material, treating the
substantially flat continuous material with corona discharge and
forming the corona treated substantially flat continuous material
into an endless rod. Further steps comprise providing a wrapper,
applying adhesive to the wrapper and wrapping the endless rod with
the wrapper. Therein the step of applying adhesive to the wrapper
comprises applying adhesive over a width of the wrapper and in a
central portion of the wrapper.
Inventors: |
SANNA; Daniele; (Castel
Maggiore, IT) ; BONICI; Alberto; (Modena,
IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
PHILIP MORRIS PRODUCTS S.A. |
Neuchatel |
|
CH |
|
|
Family ID: |
52130051 |
Appl. No.: |
15/515252 |
Filed: |
December 9, 2015 |
PCT Filed: |
December 9, 2015 |
PCT NO: |
PCT/EP2015/079115 |
371 Date: |
March 29, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A24D 3/0233
20130101 |
International
Class: |
A24D 3/02 20060101
A24D003/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 2014 |
EP |
14196985.7 |
Claims
1. Method for manufacturing a wrapped endless rod of substantially
flat continuous material, the method comprising the steps of:
providing a substantially flat continuous material; treating the
substantially flat continuous material with corona discharge;
forming the corona treated substantially flat continuous material
into an endless rod; providing a wrapper; applying adhesive to the
wrapper, and wrapping the endless rod with the wrapper, wherein the
step of applying adhesive to the wrapper comprises applying
adhesive over a width of the wrapper and in a central longitudinal
portion of the wrapper, and comprises applying the adhesive in
several strips over a length of the wrapper.
2. Method according to claim 1, comprising the step of guiding the
substantially flat continuous material between electrode and
counter electrode of a corona module.
3. Method according to claim 1, corona treating the substantially
flat continuous material during a treatment time in a range between
0.001 seconds and 2 seconds.
4. Method according to claim 1, comprising the step of corona
treating one side of the substantially flat continuous material and
subsequently corona treating the other side of the substantially
flat continuous material.
5. Method according to claim 1, wherein a strip of adhesive is
applied along the longitudinal central axis of the wrapper.
6. Method according to claim 1, wherein several strips are arranged
in parallel.
7. (canceled)
8. (canceled)
9. Method according to claim 1, wherein the substantially flat
continuous material is a plastics material, for example polylactic
acid.
10. Method according to claim 1, applying one type of adhesive to
the central longitudinal portion of the wrapper and another type of
adhesive to a seam portion of the wrapper.
11. Consumable comprising a segment of a wrapped endless rod
manufactured according to the method according to claim 1.
12. (canceled)
13. Apparatus for manufacturing a wrapped endless rod of
substantially flat continuous material, wherein the apparatus is
programmed to perform the method according to claim 1, the
apparatus comprising: a rod-forming unit for shaping a
substantially flat continuous material into an endless rod; a
wrapping device for providing a wrapper and for wrapping the
endless rod with the wrapper; an adhesive applicator for applying
an adhesive to the wrapper, wherein the adhesive applicator is
arranged for applying adhesive to a central portion of the wrapper;
a corona module arranged upstream of the rod-forming unit for
corona treating the substantially flat continuous material.
14. Apparatus according to claim 13, wherein an electrode of the
corona module has a lateral size corresponding to a width of the
substantially flat continuous material to be corona treated.
15. Apparatus according to claim 13, wherein a distance between
electrode and counter electrode is in a range between 0.1
millimeter and about 25 millimeter.
16. Apparatus according to claim 13, wherein the corona module
comprises a first module portion and a second module portion, the
first module portion and the second module portion each comprising
an electrode-counter electrode pair, wherein the electrode-counter
electrode pair of the first module portion is arranged and powered
to enable corona treatment of one side of the substantially flat
continuous material and the electrode-counter electrode pair of the
second module portion is arranged and powered to enable corona
treatment of the other side of the substantially flat continuous
material.
17. Apparatus according to claim 16, wherein at least one module
portion comprises two electrodes arranged next to each other in a
transport direction of the substantially flat continuous
material.
18. Apparatus according to claim 13, wherein the corona module
comprises a high frequency generator for providing frequencies in a
range between 10 kHz and 60 kHz and an alternating voltage between
15 kV and 40 kV.
Description
[0001] The invention relates to an apparatus and method for
manufacturing a wrapped endless rod of substantially flat
continuous material. Especially, it relates to an apparatus and
method for use in the manufacture of aerosol generating articles or
smoking articles or their components.
[0002] Aerosol generating articles or their components such as, for
example, filter plugs are generally manufactured at least partially
from a substantially flat continuous material, such as a paper,
tobacco or plastic web. The flat continuous material is
subsequently formed into an endless rod. The endless rod is wrapped
into a wrapper. The wrapper has been provided with glue to close
the wrapper and secure the wrapper to the endless rod. Due to the
special materials used for the production of plugs, especially
plastics materials, and the high production speed these plugs are
manufactured, the plugs may tend to displace or fall out of their
wrappers. This is particularly pronounced where the rod shaped
products or semi products have a sudden change in transport
direction, for example from a movement in the direction of the
longitudinal extension to a movement transverse to this direction.
Unsecured segments may dislodge due to inertia in the first
direction of travel. This may lead to blockage of the production
line. It may also set limits to a production speed or negatively
impact the operation of the final rod shaped product.
[0003] Thus, there is a need for an apparatus and method for
manufacturing wrapped endless rods of substantially flat continuous
material for use in the production of aerosol-generating articles
such as smoking articles. Especially, there is a need for an
apparatus and method for manufacturing wrapped endless rods of
substantially flat continuous material having improved anchoring of
a rod material to its wrapper.
[0004] According to an aspect of the invention, there is provided
an apparatus for manufacturing a wrapped endless rod of
substantially flat continuous material. The apparatus comprises a
rod-forming unit for shaping a substantially flat continuous
material into an endless rod. The apparatus also comprises a
wrapping device for providing a wrapper and for wrapping the
endless rod with the wrapper. An adhesive applicator is provided
for applying an adhesive to the wrapper before wrapping the endless
rod. The apparatus further comprises a corona module arranged
upstream of the rod-forming unit for corona treating the
substantially flat continuous material.
[0005] In the corona module, the substantially flat continuous
material is corona treated. By the corona treatment, the wetting
characteristic of at least one side of the continuous material is
improved. By this, an adhesive applied later or further downstream
in the apparatus, respectively, better wets the continuous material
and spreads over an extended portion of the continuous material
compared to the same non-corona treated material. When wrapping the
wrapper around the rod-shaped continuous material, the adhesive
then contacts the material of the rod not only in small limited
spots but in extended areas of adhesive. This improves the
anchoring of the rod material to its wrapper. Thus, the risk of
longitudinal and rotational displacement of the rod material in the
wrapper may be reduced or prevented. Thus, an inadvertent
displacement or loss of the rod material in or from its wrapper may
be prevented or its occurrence reduced. This is particularly
advantageous at high production speed and when using materials
having low relative adhesion, such as for example paper and
plastics materials.
[0006] The adhesive applicator may be arranged for applying
adhesive in a specific pattern and location onto the wrapper,
preferably to a central portion of the wrapper as will be described
in more detail below relating to the method. Preferably, an
apparatus is then programmed to perform such a method.
[0007] In addition, the corona treatment has little permanent
impact on the product characteristics due to a disappearing of the
effect typically after several days. Also little mechanical
modification of a treated material occurs during corona treatment.
Since no chemicals are required for a corona treatment, no
unintended residual of chemicals remains in or on a product
incorporating the material that has been treated by the corona
field.
[0008] Depending on the materials used for the wrapper, a corona
treatment may also improve adhesion of the wrapper material to
itself, in particular if the wrapper material is also corona
treated. Thus, also the creation of a reliable seam of the wrapper
may be supported by the corona treatment.
[0009] Since adhesives are generally materials, which are required
for the manufacturing process but not necessarily required or
desired in a final product, the amount of adhesive shall be kept at
a minimum. Through better adhesion and spreading of the adhesive
after corona treating of the rod material, an amount of adhesive
may possibly be limited and still have improved anchoring than in
wrapped endless rods of substantially flat continuous material that
have been manufactured without the additional corona treatment.
[0010] Corona treatment is an as such known electrochemical process
for surface modification, especially of plastics materials such as
polyethylene-, polypropylene- and polyester foils. Corona treatment
is performed to enhance the wettability of a surface, for example
for printing liquids. The base material, that is the material that
will be treated by the corona treatment, is exposed to high voltage
discharge occurring between an electrode and a counter-electrode,
the latter typically being at ground potential. Through corona
treatment surface tension of the treated material is altered
through ionization of the fluid surrounding the base material. If
the base material abuts the counter-electrode, only the side of the
base material facing the electrode at high voltage is treated.
Generally, the electrode is powered by a high frequency generator
with alternating voltage between 10 to 20 kV and a frequency
between 10 and 60 kHz.
[0011] According to an aspect of the apparatus according to the
invention, a shape of an electrode or of a counter electrode of the
corona module corresponds to the surface of a guiding element the
substantially flat continuous material is guided along in the
corona module. In such an embodiment, the continuous material is
guided on or over the guiding element, while passing the corona
module. The guiding element may directly serve as electrode or
counter electrode. Preferable, the guiding element is a counter
electrode. Preferably, the counter electrode is electrically
isolated. Preferably, the counter electrode is held at ground
potential. If the substantially flat continuous material is in
direct contact with the guiding element, for example a guiding
drum, the side of the continuous material contacting the guiding
element is not corona treated. In this set-up, only the side of the
continuous material facing the electrode is corona treated.
[0012] The use of a guiding element may further simplify the
handling and changeover of base material during or between
production runs. The corona module may be adapted to different
material, however, with unchanged geometric conditions. Preferably,
the continuous base material is guided through the corona module
continuously and preferably at a constant speed while the corona
module is active, that is while the continuous material is corona
treated. However, a base material may also be transported into the
corona module, placed between the electrode and counter electrode
and be corona treated while being stationary. Preferably, a
subsequent continuation of transport of the base material is
performed using a speed ramp in order to prevent abrupt pulling on
the continuous material.
[0013] Corresponding forms of electrode and counter electrode allow
for a defined, preferably constant, distance between electrode and
counter electrode.
[0014] A distance between electrode and counter electrode may be in
a range between 0.1 millimeter and about 25 millimeter. A distance
between electrode and counter electrode may preferably be in a
range between 1 millimeter and about 10 millimeter, for example 8
millimeter.
[0015] In some preferred embodiments, an electrode of the corona
module has a lateral size corresponding to a width of the
substantially flat continuous material to be corona treated. A size
of the electrode may be adapted to a size or area of the continuous
material to be corona treated. If the continuous material is corona
treated over an entire width of the material, a wetting
characteristic of an entire side of the continuous material may be
improved. Thus, an adhesive on a wrapper coming into contact with
the continuous material, preferably corona treated, is
substantially independent on the location where the continuous
material and the wrapper contact each other. Thus, an anchoring of
continuous material to the wrapper may be made more reliable and
more flexibility in adhesive application may be achieved. For
example, locations on the wrapper that are provided with adhesive
are substantially independent with respect to the arrangement of
the substantially flat continuous material when gathered into
rod-shape.
[0016] According to another aspect of the apparatus according to
the invention, the corona module comprises a first module portion
and a second module portion, wherein the first module portion and
the second module portion each comprise an electrode-counter
electrode pair. The electrode-counter electrode pair of the first
module portion is arranged and powered to enable corona treatment
of one side of the substantially flat continuous material. The
electrode-counter electrode pair of the second module portion is
arranged and powered to enable corona treatment of the other side
of the substantially flat continuous material.
[0017] To enable corona treatment of both sides of a base material,
the base material is guided through two corona module portions,
wherein the base material is corona treated. Each module portion
has an electrode-counter electrode pair. While corona treatment of
two sides of a foil or flat material is basically also possible in
a corona module having one electrode-counter electrode pair only, a
two-sided treatment is preferably performed with two subsequently
arranged electrode-counter electrode pairs. One pair may then be
optimized to the treatment of one side such that after the base
material leaves the corona module, both sides have reliably been
corona treated in the corona module. If both sides of the base
material are corona treated, a position of a contact area between
rod material and wrapper (and thus the location of adhesive on the
wrapper) becomes entirely independent on the location of an
adhesive on the wrapper and on the folding of the continuous
material into a rod. For example, a seam line or an adhesive may be
positioned anywhere on the circumference of the rod and a flat
material may be gathered to a rod shape in a well-defined manner or
completely irregularly: the adhesive on the wrapper will always
come into contact with a corona treated (side of the) rod
material.
[0018] According to a further aspect of the apparatus according to
the invention, the corona module comprises a high frequency
generator for providing frequencies in a range between 10 kHz and
60 kHz and an alternating voltage between 15 kV and 40 kV.
[0019] These frequency and voltage ranges have shown to provide
good adhesive wetting for the materials as used in the manufacture
of plugs for smoking articles, aerosol generating articles or their
components. In addition, these operation ranges of frequency and
voltage provided good results without damaging the materials,
especially plastics materials, such as, for example, polylactic
acid webs.
[0020] Substantially flat continuous materials may be continuous
material selected from the group consisting of polyethylene (PE),
polypropylene (PP), polyvinylchloride (PVC), polyethylene
terephthalate (PET), cellulose acetate (CA), and aluminium foil or
any combination thereof. Preferably, a substantially flat
continuous material as used in the method according to the
invention has a width of between about 150 millimeter and about 270
millimeter. In some preferred embodiments, the substantially flat
continuous material is a plastics material, for example polylactic
acid (PLA). A polylactic acid sheet may have a thickness between
about 10 microns and about 250 microns, preferably about 50 microns
plus or minus 5 microns.
[0021] A wrapper may be a continuous web of paper, plastics or
metal as may be used in the manufacture of smoking articles or
aerosol-generating articles. Preferably, a wrapper is a paper
wrapper. A wrapper may have a thickness between 20 microns and 250
microns, preferably between 40 microns and 180 microns.
[0022] According to the invention, there is also provided a method
for manufacturing a wrapped endless rod of substantially flat
continuous material. The method comprises the steps of providing a
substantially flat continuous material and treating the
substantially flat continuous material with corona discharge. The
method further comprises the steps of shaping the corona treated
substantially flat continuous material into an endless rod,
providing a wrapper, applying adhesive to the wrapper, and wrapping
the endless rod with the wrapper provided with the adhesive.
Preferably, the step of applying adhesive to the wrapper comprises
applying adhesive over a width of the wrapper and in a central
longitudinal portion of the wrapper. As used herein, the central
longitudinal portion is understood to include a central
longitudinal axis of the wrapper and about plus or minus 50 percent
of the entire width of the wrapper.
[0023] Adhesive is applied in the central longitudinal portion
according to a regular or irregular pattern. Preferably, adhesive
is not applied over the entire central longitudinal portion but
over one or several limited areas in the central longitudinal
portion.
[0024] Adhesive applied in the central longitudinal portion is
provided for coming into contact with the rod material, that is,
with the gathered or folded corona treated flat material. Adhesive
is also applied in a seam region, for adhering the wrapper to
itself and forming a seam. A seam region typically covers a few
percent of the width of a wrapper only. Adhesive application in a
central longitudinal portion and in a seam region may be combined
in one application step. For example, a glue pattern may extend
from the central longitudinal portion to the seam region. Adhesive
application in a central longitudinal portion and in a seam region
may be provided in separate adhesive application steps, for example
by separate applicator movements or separate applicators or both
separate movements and separate applicators.
[0025] According to an aspect of the method according to the
invention, the method comprises the step of guiding the
substantially flat continuous material between electrode and
counter electrode of a corona module.
[0026] A corona treatment of the substantially flat continuous
material may be performed during a treatment time in a range
between 0.001 seconds and 2 seconds, preferably in a range between
0.02 seconds and 0.5 seconds. These corona treatment times have
shown to increase an adhesion force between the corona treated
material and a wrapper glued to the corona treated material
particularly well. Preferably, the mentioned treatment times are
applied in a corona module having frequency and voltage ranges as
mentioned above.
[0027] Preferably, during a treatment time, the substantially flat
material is continuously transported through and between electrode
and counter electrode. If two sides of the substantially flat
continuous material are treated in two subsequent corona module
portions, a corona treatment may be performed in each of the module
portions during an above mentioned treatment time.
[0028] In some preferred embodiments of the method according to the
invention, the method comprises the step of corona treating one
side of the substantially flat continuous material and then
subsequently corona treating the other side of the substantially
flat continuous material.
[0029] Advantages and further aspects of the method according to
the invention have been described relating to the apparatus
according to the invention and will therefore not be repeated.
[0030] According to a further aspect of the method according to the
invention, the step of applying an adhesive to the wrapper
comprises applying the adhesive over a length or over a width or
over a length and a width of the wrapper. In particular, the step
of applying an adhesive to the wrapper comprises applying the
adhesive in one or several strips over a length or over a width or
over a length and a width of the wrapper. For example, one
longitudinal strip may be applied in the central longitudinal
portion of the wrapper and one longitudinal strip of adhesive may
be applied to the seam region.
[0031] Generally, an adhesive is applied longitudinally along the
wrapper such that a strip of adhesive, for example glue, is applied
and arranged along a side of the wrapper. After wrapping, the
portion of the wrapper provided with the strip of glue forms a seam
extending parallel to the longitudinal axis of the endless rod. The
width of the strip is selected such that the wrapper in the seam
region is provided with glue and that to some extent also a portion
of the wrapper adjacent to the seam region and facing the rod
material is provided with glue. While glue in the seam region is
provided for closing the wrapper, the glue facing the rod material
is provided for anchoring rod material in the wrapper. A
longitudinally arranged strip allows to manufacture a continuously
closed wrapper along the longitudinal axis of the endless rod.
Typically, two longitudinal strips are arranged along the length of
the wrapper: one strip on a lateral side for the seam and one
second strip essentially along a longitudinal central axis of the
wrapper for the anchoring.
[0032] A longitudinally arranged amount of adhesive may also be
applied, for example, in the form of a spiral. Such a spiral glue
application in a seam region is, for example, described in the
European patent EP 1 161 887 B. The application of an adhesive in
spiral form has the advantage, among others, that a width of the
spiral may easily be adapted to more or less adhesive to come into
contact with rod material. In addition, an adhesive applied
longitudinally in the form of a spiral also provides the basis for
a continuously closed wrapper along the longitudinal axis.
[0033] Therein, the glue spiral is described as having the
advantage of less adhesive required for achieving a continuously
closed wrapper along the longitudinal axis of the seam region of
the wrapper.
[0034] The term an adhesive extending `over a width` of the wrapper
preferably includes adhesive extending over at least 20 percent of
the width of the wrapper, more preferably over at least 30 percent
of the width, for example over 50 percent of the width of the
wrapper. Therein, an adhesive may be a single adhesive area, for
example a single strip, or may be a sum of several adhesive areas,
for example a sum of several strips arranged in parallel.
[0035] In order for an improved anchoring of the rod material and
the wrapper, especially to further secure the rod material against
rotational displacement inside the wrapper, an adhesive may also be
applied to extend over at least part of or entirely around the
circumference of the rod. By adhesive application over at least
part of the width of a wrapper, preferably at least half of the
width, an anchoring of the rod material in the wrapper is further
improved. Thus, this may further reduce the risk of or prevent
longitudinal and rotational displacement of the rod in the wrapper
also at high production speed and also upon using material having
low adhesion capability between rod and wrapper material. An
adhesive may for example be applied in the form of strips extending
transversely over the wrapper, that is, over the width of the
wrapper. Preferably, transverse strips are provided as a regular
pattern by means of distantly arranged strips. Preferably,
transverse strips are applied to the wrapper in a regular sequence.
Transverse strips may for example be arranged equidistantly on the
wrapper. For example, a transverse strip may be applied at a
position where the endless rod will be cut later on into individual
segments or plugs. By this, the wrapper will be secured to the rod
material, preferably along the entire circumference of the rod, at
the ends or at end regions of segments.
[0036] A transverse strip may extend over part of the width of the
wrapper or over the entire width of the wrapper. In the latter
case, adhesive is applied over an entire circumference of the rod
in between the wrapper and the rod material.
[0037] Adhesive may also be applied over a width and a length of
the wrapper thus providing a longitudinal seam as well as a
circumferential adhesion of the wrapper to the rod material.
Preferably, an adhesive applied over a width and a length in a
central longitudinal portion of the wrapper is supplemented by an
adhesive applied in a seam region.
[0038] The method may comprise the steps of applying one type of
adhesive to the central longitudinal portion of the wrapper and
another type of adhesive to a seam portion of the wrapper.
Different adhesives may, for example differ in settling time or in
their application field. If a wrapper is a paper wrapper, paper
glue may be used for the seam. If the rod material is a plastics
material, for example, specific plastics glue may be used for the
anchoring of the wrapper to such plastics rod material.
[0039] Preferably, corona treatment is performed on the base
material before any further treatments of the material is
performed, such as for example crimping, embossing, rolling,
electrostatic discharging, cooling, flavoring, gathering and
rod-forming. However, corona treatment may also be applied after a
treatment step, for example, after one or more of the above
mentioned process steps, like for example crimping of the
continuous material.
[0040] Subsequent treatments may influence the effect of the corona
treatment. However, an effect of a corona treatment has been found
to last between several hours and several days, depending on the
treated material and on the treatment steps. Typical time periods
in the apparatus according to the invention passing between corona
treatment of the base material and the wrapping of the endless rod
formed of the corona treated base material are in a range between
fractions of a second up to several minutes. Thus, this time period
is well below a time period wherein the effect typically would
disappear.
[0041] According to the invention, there is further provided a
consumable, for example an aerosol-generating article or a smoking
article. The consumable comprises a segment, for example a plug, of
a wrapped endless rod, which wrapped endless rod has been
manufactured according to the method according to the invention and
as described herein. Preferably, the plug is a PLA plug, for
example, for use as aerosol cooling segment in the consumable.
Preferably, the consumable comprises adhesive between a wrapper and
a rod material, wherein the adhesive is provided in a central
portion of the wrapper, that is, distanced from a seam region of
the wrapper.
[0042] In the consumable, adhesive may be provided
circumferentially between the wrapper and the rod material.
[0043] Further processes may be used in combination with corona
treatment to improve adhesive application and distribution on a
wrapper to improve the attachment of a rod material to its wrapper.
Such processes may for example be but are not limited to: variation
of adhesives, for example different glues (PVA glues, polar glues);
alternative wrapper materials, for example having different wetting
characteristic or having different porosity; different glue
patterns as the patterns explicitly described herein.
[0044] The invention is further described with regard to
embodiments, which are illustrated by means of the following
drawings, wherein:
[0045] FIG. 1 shows a schematic overview of an embodiment of a
filter making apparatus including corona module;
[0046] FIG. 2 shows a defective semi-finished product;
[0047] FIG. 3 shows a corona module;
[0048] FIG. 4a,4b show different glue pattern;
[0049] FIG. 5 is a measurement set-up for anchoring
measurements;
[0050] FIG. 6 depicts test results of anchoring measurements.
[0051] In the filter making apparatus schematically shown in FIG.
1, a substantially flat continuous material such as a web of
material 1 is provided on a bobbin 10. When unwound from the bobbin
10, the web 1 is corona treated, folded and wrapped in the
apparatus. In this embodiment, the web 1, for example a PLA film,
passes a corona module 2 directly after having been unwound from
bobbin 10. In the corona module 2, both sides of the web 1 are
subsequently corona treated in two corona module portions 21,22.
The corona module 2 is described in more detail with reference to
FIG. 3. After corona treatment in the corona module 2, the web 1
passes a crimping device 4, for example a set of two crimping
rollers. The crimping device 4 provides the web 1 with a crimping
structure, for example with substantially parallel corrugations
running, preferably, in longitudinal direction of the web, that is,
in transport direction of the web 1. The web 1 then passes a
shaping device. The shaping device comprises shaping rollers 50,
preferably providing the crimped web 1 with a longitudinally
running wave-like macro structure overlaying the crimping micro
structure. Imposing the overlaying macro structure onto the web 1
causes the web 1 to be pushed together in a transverse direction of
the web. In addition, a gathering of the web 1, for example into a
rod shape, is supported by the longitudinal wave-like structure and
may be performed in a more controlled manner. The shaping device
also comprises a funnelling device 51 arranged downstream of the
shaping rollers 50. In the funnelling device 51, the web 1 is
further shaped into rod-shape, for example by gathering or pushing
together. Preferably, when leaving the funnelling device 51, the
web 1 has not yet achieved its final form, or is not entirely
gathered, respectively. This facilitates the introduction of an
object, such as a capsule or flavoured thread 71, into the endless
rod of web material. A flavour application system 7 comprising an
endless thread 71 and a flavour reservoir 72 is arranged downstream
of the shaping device. The thread 71 is mounted on a bobbin 70.
Preferably, the flavour reservoir 72 contains menthol. The thread
71 is unwound from the bobbin 70 and entrained with flavour before
being transported to the gathered web 1. The flavour application
system 7 may be provided with at least one of a flow meter, a
valve, a temperature control and a pump for control and provision
of a defined amount of flavour to be applied to the thread 71. The
flavour application system 7 is arranged above the web 1 in order
for gravity to support the introduction of the thread into the web.
Gravity may also support a flow of flavouring liquid along the
thread 71. Alternatively, or in addition, flavour may be added
separately from the thread 71 or may be entirely omitted. In that
case, the presence of the thread may have mostly an aesthetic
contribution to the aerosol-generating article.
[0052] An endless wrap material 6, for example paper, is provided
on a bobbin 60 and supplied from below the endless rod such that
the endless rod of web material comes to lie on the wrap material
6. The wrap material 6 runs parallel to the endless rod when being
joined with the rod. Before the wrap material 6 and the endless rod
are joined, the wrap material is provided with glue. A glue
reservoir 62 is in fluid connection with a seam nozzle 64 as well
as with an anchor nozzle 63. Glue from the glue reservoir 62 is
transported via a glue conduit, for example a tube, to the anchor
nozzle and the seam nozzle. With the anchor nozzle 63, anchoring
glue is applied to the wrap material, preferably, in a more central
region of the wrap material 6. Preferably, anchoring glue is
applied in lines transverse to the wrap material 6. The lines or
anchoring glue, respectively, are provided for contacting the web
material such that the wrapper is securely glued to the web
material--thus the rod material is anchored in the wrapper. With
the seam nozzle 64, seam glue is applied to the wrap material 6,
preferably, along a lateral side of the wrap material 6.
Preferably, the seam glue is applied in one longitudinal line,
preferably one continuous line. The longitudinal line is provided
for gluing the wrap material to itself after the wrap material has
been entirely wrapped around the endless rod of web material. Thus,
the wrap material forms a secure and preferably continuous
seam.
[0053] Preferably, the glue reservoir 62 contains a liquid glue,
which may be used for both the anchoring and the seaming of the
wrap material. However, if different glue shall be used, a
reservoir each for the anchoring and for the seaming may be
provided. Different glues may be advantageous, for example, if a
wrap material is a paper wrapper and paper glue shall be used for
the seam and if, for example, specific plastics glue shall be used
for the anchoring of the wrapper to a plastics web material of the
endless rod. Also, glues may vary with respect to the settling time
for the glue. For example a polyurethane glue and a hot-melt glue
may be used for different purposes.
[0054] The so wrapped endless rod of web material may be guided in
a rod-shaped bed 52 passing a heating device 53 for heating the
wrapped endless rod. The heating facilitates a distribution and
fast drying of the glue. After the endless rod has been formed, it
is cut in the cutting device 8 into rod segments of predefined
length, for example single or double length segments (having the
length or the double length of a final product). The rod segments
may be transported to a tray or storage 91. The rod segment may
also directly be transported to a combiner 92 for being combined
with further elements, for example further filter elements or
segments of, for example, aerosol generating articles.
[0055] An online control unit 90 is provided after the endless rod
has been cut into segments for a quality control of the
manufactured segments. At the location of the tray 91, there may be
provided an offline control unit 93. An online control unit 90 and
offline control unit 93 may, for example, include a length control,
diameter control, a weight control, ovality control, a control of
the resistance to draw (RTD), the thread centering and other visual
quality aspects of the semi-finished or finished good. The offline
control unit 93 may for example also be provided with a measuring
device for a menthol content or other substances in the rod
segment. In the tray 91, the segments may be labelled, for example
with a batch number, production date or product code, for example,
for tracking of the products.
[0056] Preferably, tension rollers 30 and driving rollers 31 are
provided in the apparatus for a controlled transport of the web of
material 1 and a continuous, preferably constant, tensioning of the
web. Synchronization means may be provided between crimping device
4 and a transport means such as a continuous belt, for example, at
the position of the online control unit 90. By the synchronization
means a linear speed of the endless rod and of the yet to be
gathered substantially flat continuous material fed into the
crimping device 4 may be synchronized.
[0057] Instead of having an apparatus, where the corona treatment
is performed inline, a base material may also be corona treated
previously and then supplied to the filter making apparatus.
[0058] FIG. 2 schematically shows a semi-finished product
manufactured from rod segments, for example as produced in an
apparatus similar as shown in FIG. 1, however without the corona
module and without corona treating of the PLA foil. Two rod
segments comprising a plug of PLA foil 1 wrapped with a paper
wrapper 6 are aligned with their longitudinal axis with a further
rod-shaped segment 11 arranged in between the PLA plugs. The
further rod-shaped segment 11 may be a further filter element or
may also be a plug of an aerosol-forming substrate, for example a
tobacco plug. The further rod-shaped segment 11 is a double segment
and combined with the two rod segments with an additional wrapper
13. During the combining step, the weak adhesion between PLA plug 1
and paper wrapper 6 makes the plug shift in the wrapper 6 by a
shift distance 12. Such a shift distance may be up to a several
millimetres. If a shift distance 12 is above a predefined distance,
the product is typically regarded as being defective and will be
removed.
[0059] In FIG. 3 a PLA film 1 is guided through a corona module 2
comprising two corona module portions 21, 22. The PLA film may be
guided via guide rollers 200 into and out of the corona module 2.
The set-up of the two corona module portions 21, 22 is
substantially identical. The two corona module portions 21, 22 are
arranged such that the PLA film is guided through the module
portions 21, 22 in an s-form such that one side of the PLA film is
corona treated in the first module portion 21. The other side of
the PLA film is corona treated in the second module portion 22
arranged downstream and subsequently to the first module portion
21. A corona module portion 21,22 comprises a transport drum 20,23
as a counter-electrode. Preferably, transport drum 20,23 is at
ground potential. The PLA foil 1 substantially performs a U-turn
and lies closely against the transport drum 22,23 when being guided
around the transport drum 20,23. A corona module portion also
comprises an electrode 212,222 connected to a power generator unit
211,221 providing power and frequency of a voltage applied to the
electrode 212,222. Electrode 212,222 and power generator 211,221
are arranged in a housing 210,220. The housing 210,220 is movably
mounted for being moved away and towards the transport drum 20,23
for mounting and maintenance purposes. Preferably, the distance
between electrode 212, 222 and counter electrode 20,23 may be set
by the movable housing 210,220. The retracted positions of the
housing is indicated with dotted lines 2100,2200. The electrode
212,222 comprises a concave shape corresponding to the
circumference of the transport drum 20,23. The PLA foil 1 is guided
between electrode 212,222 and counter electrode 20,23 and may
thereby be corona treated on the side of the PLA foil facing the
respective electrode.
[0060] In FIGS. 4a and 4b sections of an endless wrap material 6
are shown. Individual strips of adhesive 630 are applied along the
width 602 of the wrap material 6. The strips 630 are intended for
an anchoring of the wrap material 6 to the web material 1. The
strips 630 do not extend entirely up to the lateral edges of the
wrap material, such as not to cover a seam region for a wrapper
seam or a seam glue line applied in the seam region, respectively.
However, when being wrapped around a rod-shaped PLA plug, the
strips preferably extend along the entire circumference of the PLA
plug.
[0061] If the anchoring strips 630 are also used for a seam of the
wrap material 6, the strips may also extend up to the lateral edges
of the wrap material.
[0062] The strips 630 are applied and distributed along the length
of the wrap material. Preferably, they are arranged equidistantly
over the length of the wrap material 6. Individual wrapper segments
601 are indicated by cutting lines 80,81. The cutting lines 80,81
correspond to a position the endless rod is subsequently cut into
rod segments. Preferably, a strip pattern has predetermined values
of, for example, the distances between strips, the number of strips
and the width of strips. Preferably, the predetermined values are
selected according to a length 603 of an individual wrapper segment
601.
[0063] In FIG. 4a, two strips 630 per wrapper segment 601 are
provided, while the wrap material 6 is cut between strips. In FIG.
4b, only one strip 630 at half length of the wrap material 6 per
segment is provided.
[0064] A width 602 of the wrap material 6 may be between 23
millimeter and 30 millimeter, for example 28 millimeter. A length
603 of the individual wrapper segments may be between 8 millimeter
and 20 millimeter, for example 12 millimeter. A width between
strips 630, where one strip per wrapper segment is provided is
preferably identical to a wrapper segment length 603. However, all
these values may be adapted to a cross section and length of a rod
segment to be cut from the endless rod of web material and to be
wrapped in a wrapper segment 601.
[0065] FIG. 5 shows a measurement set-up for measuring an anchoring
of a PLA rod 1 in its plug wrapper 6. For this measurement the
wrapped PLA plug is pierced onto a pin 18 provided with an extended
base. An adhesive tape 18 is attached to the wrapper 6. Preferably,
the adhesive force between adhesive tape 18 and wrapper 6 is
stronger than an adhesive force between wrapper 6 and PLA plug 1.
Pin 1 and adhesive tape 18 are each fixedly held in a force
measurement device 16, for example, dynamometer grip cells. The two
dynamometers pull at the tape and the plug in opposite directions
as indicated by arrows 17.
[0066] In FIG. 6 results of PLA anchoring measurements performed
with the set-up as shown in FIG. 5 are depicted. FIG. 6 shows that
the anchoring strength can be improved by the corona treatment,
when comparing samples of non-corona treated PLA foil 15 and corona
treated PLA foil 65. Routinely, a doubling or tripling of the
anchoring strength may be achieved by the corona treatment of the
PLA foil. An additional effect is apparent between different glue
patterns 631 provided on the paper wrapper 6. Random spiral, double
longitudinal strips and square or transverse strips show enhanced
anchoring compared to the commonly used single longitudinal strip
170. If corona treatment is combined with a dedicated glue pattern,
anchoring strength may significantly be enhanced and a number of
defective products may significantly be reduced.
[0067] The amount of defective semi-finished products (as shown in
FIG. 2) comprising non-corona treated polylactic acid foil glued to
a paper wrapper provided with one longitudinal glue line along the
central axis of the wrapper have been compared with the amount of
defective semi-finished products comprising corona treated
polylactic acid foil glued to a paper wrapper provided with glue
strips extending transverse to the wrapper. Products were
identified as defective if the shift distance 12 between PLA plug 1
and wrapper 6 amounted to more than 1 millimeter. Comparison showed
that the number of defective products could be reduced by about 120
times (29 defective semi-finished products per one tray 91 compared
to one defective semi-finished product per four trays 91).
* * * * *