U.S. patent application number 15/029457 was filed with the patent office on 2016-08-25 for packaging unit having improved sealing and a method of forming a packaging unit having improved sealing.
This patent application is currently assigned to SCA Hygiene Products AB. The applicant listed for this patent is SCA HYGIENE PRODUCTS AB. Invention is credited to Sofia EKSTEDT.
Application Number | 20160242971 15/029457 |
Document ID | / |
Family ID | 52993231 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160242971 |
Kind Code |
A1 |
EKSTEDT; Sofia |
August 25, 2016 |
PACKAGING UNIT HAVING IMPROVED SEALING AND A METHOD OF FORMING A
PACKAGING UNIT HAVING IMPROVED SEALING
Abstract
A packaging unit for hygiene articles is formed from a sheet of
material having an inner surface and an outer surface. The inner
surface includes an edge zone including an inner edge portion and
an outer edge portion. The sheet has at least one folding axis
dividing the sheet into a first region and a second region. The
inner edge portion and the outer edge portion of the edge zone of
the first region is provided with adhesive, and the other of the
inner edge portion and the outer edge portion of the edge zone of
the first region is adhesive-free. Further, one of the inner edge
portion and the outer edge portion of the edge zone of the second
region is provided with adhesive, and the other is adhesive-free in
a complementary manner to the edge zone of the first region.
Inventors: |
EKSTEDT; Sofia; (Goteborg,
SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SCA HYGIENE PRODUCTS AB |
Goteborg |
|
SE |
|
|
Assignee: |
SCA Hygiene Products AB
Goteborg
SE
|
Family ID: |
52993231 |
Appl. No.: |
15/029457 |
Filed: |
October 14, 2014 |
PCT Filed: |
October 14, 2014 |
PCT NO: |
PCT/SE2014/051215 |
371 Date: |
April 14, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B65D 2575/586 20130101;
B65D 2209/00 20130101; A61F 13/15739 20130101; A61F 13/551
20130101; A61F 13/15747 20130101; B32B 37/12 20130101; B31B 2150/00
20170801; B31B 70/64 20170801; B65D 65/14 20130101; A61F 13/5515
20130101; B65D 75/20 20130101; B65D 75/58 20130101; B31B 2160/10
20170801; B32B 38/0004 20130101; B32B 2555/02 20130101; A61F
13/55135 20130101; B31B 2160/102 20170801; B31B 70/00 20170801;
A61F 13/5514 20130101 |
International
Class: |
A61F 13/551 20060101
A61F013/551; B32B 38/00 20060101 B32B038/00; B65D 75/20 20060101
B65D075/20; B32B 37/12 20060101 B32B037/12; A61F 13/15 20060101
A61F013/15; B65D 65/14 20060101 B65D065/14 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 23, 2013 |
SE |
PCT/SE2013/051233 |
Claims
1-22. (canceled)
23. A packaging unit for hygiene articles, the unit being formed
from a sheet of material, said sheet having an inner surface and an
outer surface, said inner surface comprising an edge zone
comprising an inner edge portion and an outer edge portion, said
sheet having two folding axes, dividing said sheet into a first
region, a second region and a third region, wherein said packaging
unit may be folded along said folding axes with said first, second
and third regions in an overlapping configuration, wherein one of
said inner edge portion and said outer edge portion of said edge
zone of said second region is provided with resealable adhesive,
and the other of said inner edge portion and said outer edge
portion of said edge zone of said second region is adhesive-free
and is provided with a release agent; one of said inner edge
portion and said outer edge portion of said edge zone of said first
region and one of said inner edge portion and said outer edge
portion of said edge zone of said third region are provided with
resealable adhesive in a complementary manner to said edge portion
being provided with adhesive in said second region such that a
chessboard pattern of resealable adhesive is formed along said edge
zone; and the other of said inner edge portion and said outer edge
portion of said edge zone of said first region and the other of
said inner edge portion and said outer edge portion of said edge
zone of said third region are free from resealable adhesive and
from release agent.
24. The packaging unit according to claim 23, wherein the area of
said adhesive-free edge portion of said second region being covered
with the release agent constitutes 10-90% of said adhesive-free
edge portion of said second region.
25. The packaging unit according to claim 23, wherein a release
agent is provided along the entire length of said adhesive-free
edge portion of said second region.
26. The packaging unit according to claim 23, wherein the release
agent is applied in a continuous pattern or as a coating.
27. The packaging unit according to claim 23, wherein the release
agent is applied in an intermittent pattern.
28. The packaging unit according to claim 23, wherein the total
adhesive force between said inner edge portion in said first region
and said inner edge portion in said second region, and between said
outer edge portion in said first region and said outer edge portion
in said second region is 0.5-2.5 N.
29. The packaging unit according to claim 23, wherein the total
weight of said resealable adhesive in said first, second and third
regions is 0.05-0.1 g.
30. The packaging unit according to claim 23, wherein the release
agent is a silicone polymer or a polysiloxane.
31. The packaging unit according to claim 23, wherein said
packaging unit is of substantially rectangular shape and comprises
longitudinal edges, transverse edges and corner portions, said edge
zones of said first, second and third regions of said sheet of
material being arranged along said longitudinal edges.
32. The packaging unit according to claim 23, wherein said
packaging unit comprises transverse edge zones and wherein at least
a portion of one of said transverse edge zones is provided with
resealable adhesive, while the remaining portion of said transverse
edge zone is adhesive-free.
33. The packaging unit according to claim 32, wherein at least a
section of said adhesive-free transverse edge portion is provided
with a release agent.
34. The packaging unit according to claim 23, wherein said
resealable adhesive is a pressure-sensitive hotmelt adhesive with
unlimited open time.
35. The packaging unit according to claim 23, wherein said
packaging unit is reclosable.
36. A series of packaging units according to claim 23, wherein said
packaging units have been reclosed, and wherein 50%-100% of said
reclosed packaging units in said series of reclosed packaging units
remain sealed after 10 min from the reclosing occasion.
37. A method of forming a packaging unit for hygiene articles from
a sheet of material, comprising the steps of: providing a sheet
having an inner surface and an outer surface, said inner surface
comprising an edge zone comprising an inner edge portion and an
outer edge portion, said sheet having two folding axes, said
folding axes dividing said sheet into a first region, a second
region, and a third region; providing one of said inner edge
portion and said outer edge portion of said edge zone of said
second region with a release agent; providing the other one of said
inner edge portion and said outer edge portion of said edge zone of
said second region being free from said release agent with
resealable adhesive; providing one of said inner edge portion and
said outer edge portion of said edge zone of said first region and
one of said inner edge portion and said outer edge portion of said
edge zone of said third region with resealable adhesive in a
complementary manner to said edge portion of said second region
being provided with resealable adhesive; such that a chessboard
pattern of resealable adhesive is formed along said edge zone; and
such that the other of said inner edge portion and said outer edge
portion of said edge zone of said first region and the other of
said inner edge portion and said outer edge portion of said third
region are adhesive-free; folding the sheet about said first
folding axis, such that the edge portion carrying resealable
adhesive in said first region is brought in contact with the edge
portion carrying release agent in said second region; folding the
sheet about said second folding axis, such that the edge portion
carrying resealable adhesive in said third region is brought in
contact with the outer surface of said first region.
38. A web of material for forming packaging units for hygiene
articles, said web of material having a longitudinal direction
running along a longitudinal central axis and a transverse
direction perpendicular to the longitudinal direction, said web
comprising a plurality of transverse cutting zones, each of said
transverse cutting zones being arranged along a respective central
cutting axis running in said transverse direction of said web, said
transverse cutting zones being positioned at a distance from each
other in said longitudinal direction of said web, each of said
transverse cutting zones comprising a central portion and a first
and a second peripheral portion arranged on either side of said
central portion in said transverse direction of said web, wherein a
section of each of said central portion, said first and said second
peripheral portion of each of said transverse cutting zones of said
web are provided with a release agent, and each of said transverse
cutting zones is provided with resealable adhesive in a section of
each of said central portion, said first and said second peripheral
portion of said transverse cutting zone being free from release
agent, such that said section provided with a resealable adhesive
in said central portion of said transverse cutting zone is
displaced in said longitudinal direction in relation to the said
sections provided with a resealable adhesive in said first and said
second peripheral portions of said transverse cutting zone, such
that a chessboard pattern of resealable adhesive is formed along
each of the transverse cutting zones.
39. The web of material according to claim 38, wherein said
material is a plastic film, a nonwoven web or a laminate.
40. The web of material according to claim 38, wherein said web of
material has a width in said transverse direction of 10-50 cm.
41. The web of material according to claim 38, wherein said
transverse cutting zone has a width in said longitudinal direction
of said web of 0.5-5 cm.
42. A manufacturing method for providing a web of material for
forming packaging units for hygiene articles, comprising the steps
of: a) providing a web of material having a longitudinal direction
running along a longitudinal central axis and a transverse
direction perpendicular to the longitudinal direction, said web
running in machine direction (MD) such that said longitudinal
direction of said web coincides with said MD, said web comprising a
plurality of transverse cutting zones, each of said transverse
cutting zones being arranged along a central cutting axis running
in said transverse direction of said web, said transverse cutting
zones being positioned at a distance from each other in said
longitudinal direction of said web, each of said transverse cutting
zones comprising a central portion and a first and a second
peripheral portion arranged on either side of said central portion
in said transverse direction of said web; b) providing a section of
said central portion, said first and said second peripheral portion
of each of each of said transverse cutting zones of said web with a
release agent in said transverse direction of said web; c)
providing a section of each of said central portion, said first and
said second peripheral portion of the remaining portion of each of
said transverse cutting zones of said web being free from release
agent with resealable adhesive in said transverse direction of said
web, such that said section provided with a resealable adhesive in
said central portion of said transverse cutting zone is displaced
in said longitudinal direction in relation to the said sections
provided with a resealable adhesive in said first and said second
peripheral portions of said transverse cutting zone, such that a
chessboard pattern of resealable adhesive is formed along each of
the transverse cutting zones. d) cutting said web through said
transverse cutting zones along said central cutting axes, wherein
steps b) and c) are carried out in any order.
Description
TECHNICAL FIELD
[0001] The present invention relates to a packaging unit for
hygiene articles, the unit being formed from a sheet of material,
the sheet having an inner surface and an outer surface, the inner
surface comprising an edge zone comprising an inner edge portion
and an outer edge portion, the sheet having two folding axes, the
folding axes dividing the sheet into a first region, a second
region and a third region, wherein the packaging unit may be folded
along the folding axes with the first, second and third regions in
an overlapping configuration. The present invention also relates to
a method of forming a packaging unit for hygiene articles from a
sheet of material, a web of material for forming packaging units,
as well as to a method of forming a web of material for forming
packaging units.
BACKGROUND OF THE INVENTION
[0002] Disposable hygiene articles, such as sanitary napkins and
panty liners, are normally packaged individually in e.g. an easy
wrap or a single wrap. Individual packages facilitate hygienic
carrying of single articles for future use, e.g. in a handbag. The
edges of the individual packages are often sealed by means of
ultrasonic welding or heat welding. Further, the packaging units
are often used both as a means for packaging an unused article and
for disposal of the used article.
[0003] It is desirable that used articles of this kind can be
disposed of discretely and hygienically.
[0004] This may be particularly important when the user lacks the
possibility to dispose of the used article immediately after the
used article has been replaced, e.g. when there is no waste bin
available in the toilet area. In this case, the user may need to
put the used article in e.g. the handbag or backpack, which
requires that the package is tightly sealed in order to avoid
staining and odour.
[0005] The disposal problem has been an object of quite an
intensive investigation, and several solutions have been
suggested.
[0006] GB 2 153 779 discloses a wrapper sheet that may be provided
with a pouch formed by overlaying at least a portion of the wrapper
with a sheet of liquid impermeable material which is affixed to the
wrapper on three sides. The pouch is used to receive the soiled
article. Such a wrapper suffers from disadvantages of requiring an
additional amount of material, and not being able to form a tight
disposal package.
[0007] Another common solution for disposing of used hygiene
articles is disclosed in e.g. WO 94/14396. This document discloses
a fold and wrap package comprising a wrapper comprising a single
strip of material having a flap panel, a central panel and an end
panel, and a tape tab for securing the wrapper in a disposal
configuration. A major disadvantage of such a wrapper is that it is
not possible to form a tightly sealed package when the article is
to be disposed of.
[0008] WO 88/10219 discloses a packaging unit which is formed by
folding an elongated sheet of material provided along the mutually
parallel edges thereof with a continuous or broken narrow coating
of pressure-sensitive adhesive by means of which the container part
is held together, with adhesive surfaces lying against and bonding
to adhesive surfaces. The packaging unit further comprises a lid
coated at least partially with a pressure-sensitive adhesive so as
to enable the lid to be refastened to the outside of the container
part. Such a packaging unit thus has very strongly sealed side
seams where the adhesive-coated surfaces are in contact with each
other, and a resealable lid providing a tightly sealed disposal
package. However, since the adhesive-coated surfaces are in contact
with each other, it is impossible to unfold the sheet completely
for positioning of a used item, which thus has to be inserted into
the rather limited container part. This may be disadvantageous,
since a used hygiene article often becomes more bulky than before
use, making it difficult to insert it into the container part.
[0009] US H 1454 discloses a reclosable sheet for packaging and
disposal of hygiene articles. The sheet comprises edge adhesive
strips positioned such that when the sheet is folded, the
adhesive-coated areas do not come into contact with each other. In
order to serve its purpose, the folding of the sheet has to be
initiated from the adhesive-free transverse edge of the sheet. If
the folding is initiated from the adhesive-coated transverse edge,
two layers of adhesive will overlap each other, and the
adhesive-free transverse edge will be positioned at the outer
position of the package, i.e. the package will not be tightly
sealed.
[0010] A conventional type of packaging unit intended for packaging
single articles comprises an elongated rectangular sheet of
material which is folded to form a bag-like package with a
folded-over lid, also called e-folding. These known packaging units
are welded along the edges by means of heat or ultrasound, and are
opened by tearing along the welded seams at the edges, so that the
package may be unfolded to expose the contents of the package.
[0011] The main drawback of welded packaging units of this kind is
that they cannot be used satisfactorily as disposal bags since,
once opened, the packages cannot be resealed and therefore do not
allow a used article to be packaged in an acceptable manner with
regard to hygiene. Furthermore, the unfolded packaging sheet has
non-aesthetic appearance, since the broken welds are often uneven
and frilly.
[0012] Hence there is a need for a packaging unit which can be used
both for packaging a new hygiene article and for sanitary keeping
and disposing of a used hygiene article, which is easily opened and
securely resealed, and which is aesthetically appealing.
SUMMARY OF THE INVENTION
[0013] The present invention provides a packaging unit which can be
used both for packaging a new hygiene article and for safe and
sanitary disposing of a used hygiene article. The packaging unit of
the present invention provides a possibility of forming a tight
package both for a new and a used article, thus keeping the new
article sanitary and clean prior to use, and eliminating the risk
of staining and odour when a used article is packaged. The
packaging unit is easy to unfold and reseal, and is aesthetically
appealing.
[0014] As used herein, the term "inner surface" refers to the
surface of the packaging unit facing the product positioned inside
the packaging unit, and the term "outer surface" refers to the
surface opposite to the inner surface, i.e. the surface facing the
ambient.
[0015] By the term "edge zone" is meant a portion of the packaging
unit adjacent to the edges of the packaging unit. The width of an
edge zone may be varied.
[0016] The term "inner edge portion" refers to the portion of the
edge zone positioned towards the centreline of the packaging
unit.
[0017] The term "outer edge portion" refers to the portion of the
edge zone positioned towards the edge of the packaging unit.
[0018] By the term "single ply" is meant a packaging unit
comprising a single ply of a coherent material. The examples of a
single ply packaging unit may be a plastic film, such as a
polyethylene film, a nonwoven material, a metallic foil or the
like. A single ply material may be a non-homogenous material such
as a plastic film material comprising integrated layers or a
nonwoven material having varying fibre composition in different
parts of the material. A single ply material as used herein does
not comprise materials having separable layers.
[0019] By the term "laminate" is meant a packaging unit comprising
at least two united separable plies of material that can be the
same or different. In the context of the present invention, the
laminate may for example be constituted of two separable plies of
plastic film, a film and nonwoven, two plies of nonwoven, or the
like.
[0020] By the term "transverse cutting zone" is meant an area of
the web of material where an incision is made in order to separate
a piece of the web of material, thus forming a sheet for forming a
packaging unit of the present invention.
[0021] By the term "release agent" is meant a substance being able
to adjust the adhesive strength of an adhesive.
[0022] By the term "resealable adhesive" is meant an adhesive that
provides a non-permanent adhesive bond between two adherent
surfaces, i.e. a bond that may be broken by applying a pulling
force to the adherent, and recreated by applying a pressing force
to the adherent.
[0023] The present invention provides a packaging unit for hygiene
articles and a method of forming a packaging unit, which
substantially eliminate the drawbacks of the packaging units
discussed above.
[0024] The packaging unit for hygiene articles according to the
present invention is formed from a sheet of material having an
inner surface and an outer surface, the inner surface comprising an
edge zone comprising an inner edge portion and an outer edge
portion. The sheet has two folding axes, i.e. a first folding axis
and a second folding axis, the folding axes dividing the sheet into
a first region, a second region and a third region, such that the
packaging unit may be folded along the folding axes with the first,
second and third regions in an overlapping configuration. The
packaging unit according to the present invention is characterized
in that one of the inner edge portion and the outer edge portion of
the edge zone of the second region is provided with resealable
adhesive, and the other of the inner edge portion and the outer
edge portion of the edge zone of the second region is adhesive-free
and is provided with a release agent. The release agent is provided
in order to be able to control the adhesive strength of the
resealable adhesive used in the present invention.
[0025] Further, one of the inner edge portion and the outer edge
portion of the edge zone of the first region and one of the inner
edge portion and the outer edge portion of the edge zone of the
third region are provided with resealable adhesive in a
complementary manner to the edge portion being provided with
resealable adhesive in the second region such that a chessboard
pattern of resealable adhesive is formed along the edge zone.
Moreover, the other of the inner edge portion and the outer edge
portion of the edge zone of the first region and the other of the
inner edge portion and the outer edge portion of the edge zone of
the third region are free from resealable adhesive and from release
agent. When the sheet is folded about the first folding axis, the
edge portion carrying resealable adhesive in the first region is
brought in contact with the edge portion carrying release agent in
the second region, and the edge portion carrying resealable
adhesive in the second region is brought in contact with the
adhesive-free edge portion in the first region, thus forming a
pocket. When the packaging unit is folded around the second folding
axis, the edge portion carrying resealable adhesive in the third
region is brought in contact with the outer surface of the
packaging unit in the first region, thus forming a lid. Such a
folding of a packaging unit is commonly referred to as
e-folding.
[0026] It has been discovered that providing release agent on one
of the edge portions of the second region, while keeping the
adhesive-free edge portions of the first and the third region free
from release agent, provides a packaging unit having advantageous
properties when considering adhesive strength and reclosability of
the packaging unit.
[0027] A suitable resealable adhesive to be used with the packaging
unit of the present invention is pressure-sensitive hotmelt
adhesive, e.g. PT231 F from Savare having an unlimited open time,
meaning that the adhesive can bond to another substrate at any
time. The total weight of the resealable adhesive in the first,
second and third regions may be 0.05-0.1 g.
[0028] The pressure-sensitive adhesive used with the packaging unit
is one which has a very high self-adhesion but which can be readily
separated or released from other materials, such as plastic
materials or paper which has been treated with a release agent. A
major advantage of the packaging unit according to the present
invention is that it can be completely unfolded when a new hygiene
article is about to be taken out. In contrast thereto, prior art
packages having adhesively sealed edges with adhesive-coated edge
portions being in contact with each other have too high adhesive
strength of the adhesively sealed edges, and any attempt to
completely unfold the package would lead to tearing and breakage of
the packaging unit, making it unusable for discrete and hygienic
disposal of the used article. As the adhesive-coated edge portions
of the packaging unit of the present invention are not in contact
with each other when the packaging unit is folded, the packaging
unit can be readily opened and resealed, providing a tight disposal
package. At the same time, due to the presence of release agent in
the second region, tensile strength of the adhesively sealed edges
of the pocket of the packaging unit using the adhesive pattern of
the present invention is sufficient to provide a tight package for
both a new and a used article, and low enough to provide a
readily-opened package.
[0029] Using a release agent in the second region of the packaging
unit permits the provision of a packaging unit comprising an
adhesive having adequate strength to keep the packaging unit
tightly sealed prior to opening, while the packaging unit may still
be opened without using unduly high forces, potentially destroying
the packaging unit and making it unsuitable for disposal purposes,
and at the same time strength sufficient to form a tight packaging
unit when the packaging unit is resealed.
[0030] Moreover, addition of the release agent prevents migration
of the adhesive, which means that the adhesive remains in its
original position when the packaging unit is opened, rather than
being transferred to the surface being with contact with the edge
portion carrying adhesive when the packaging unit is sealed. Such a
migration of adhesive is undesirable, since it increases the
pulling force needed to open the packaging unit, and deteriorates
the reclosability of the packaging unit when the packaging unit is
resealed, since the migrated adhesive may form lumps, thus reducing
the adhesive area available for formation of the resealed adhesive
bond.
[0031] The release agent may form a coating covering the entire
adhesive-free edge portion of the second region of the packaging
unit. Also, the release agent may be applied in a pattern
throughout the entire length of the adhesive-free edge portion of
the second region. The pattern may be continuous, such as spiral,
wave, zigzag, helix, or intermittent, such as lines, dots, crosses,
stars, squares. Further, it is conceivable that the release agent
is arranged on a section of the adhesive-free edge portion of the
second region. The area of the section covered with a release agent
may constitute 10-90% of the total area of the adhesive-free edge
portion of the second region, preferably 20-85%, more preferably
60-75% of the total area of the adhesive-free edge portion of the
second region.
[0032] The release agent useful in the present invention may be a
silicone-based release agent, or low-adhesion backsize coating
(known as LAB coatings), exemplified by, but not limited to, those
disclosed in WO99/11683, U.S. Pat. No. 5,571,586 or U.S. Pat. No.
7,004,320. In general, the invention is carried out by coating
paper or plastic film with a nonstick coating, sometimes termed a
release coating, such as a silicone polymer coating or a
polysiloxane. Polysiloxanes are particularly useful non-stick
coatings, and both solvent-based and solvent-free polysiloxanes can
be used. The polysiloxanes are cured either thermally or by
radiation.
[0033] In order to provide a packaging unit having an optimal
compromise between the adhesive strength when the packaging unit is
sealed, and the pulling force needed to open the packaging unit, an
intensive investigation has been carried out, as will be described
in greater detail below. It has been found that the user perceives
the packaging unit as securely sealed prior to opening, and at the
same time find the packaging unit to be easily opened when the
total adhesive force between the inner edge portion in the first
region and the inner edge portion in the second region, and between
the outer edge portion in the first region and the outer edge
portion in the second region, i.e. the adhesive strength of the
pocket, is 0.5-2.5 N, preferably 1.5-2 N.
[0034] Preferably, the adhesive force between the edge portion
carrying adhesive in the third region and the outer surface of the
first region, i.e. the adhesive strength of the lid, is the same or
sufficiently the same as the adhesive strength of the pocket, which
makes the packaging unit to be perceived as being opened smoothly
and evenly. Thus, the adhesive force between the edge portion in
the third region being provided with adhesive and the outer surface
of the first region may be 0.5-2.5 N, preferably 1.5-2 N. However,
the adhesive strength of the lid may be different from the adhesive
strength of the pocket.
[0035] The prevailing shape of the sheet of material for forming a
packaging unit is square or rectangular. Such a sheet according to
the present invention has side edges, referred to herein as
longitudinal edges, transverse edges and corner portions, the edge
zones of the first and second regions of the sheet of material
being arranged along the longitudinal edges. The edge portions
covered with adhesive, the adhesive-free portions and the portions
carrying a release agent are thus positioned along the longitudinal
edges. In order to avoid that the edges of the sheet curl up or
crinkle when the packaging unit is opened, the adhesive provided on
the outer edge portions may be positioned at a distance from the
longitudinal edges. This distance may be between 0.5-5 mm,
preferably between 1-3 mm.
[0036] The width of the adhesive-covered edge portions may be
varied depending on the adhesive strength desired. The wider the
adhesive-covered edge zones, the stronger the sealing. The width of
the adhesive-covered edge portions may be same or different in the
different regions. Moreover, the amount of the resealable adhesive
may be same or different in different regions.
[0037] The length of the adhesive-covered edge portions in each
region may be equal to the length of each region, or may be 0.1-1
millimetres shorter than the length of each region.
[0038] Preferably, the length of the adhesive-covered edge portions
in each region is equal to the length of each region.
[0039] Further, at least one of the transverse edges of the
packaging unit according to the present invention is preferably
provided with adhesive. In order to facilitate opening, at least
one of the corner portions may be free from adhesive such that a
gripping tab is formed.
[0040] The sheet for forming a packaging unit may be a single ply
sheet of any suitable material known to the person skilled in the
art, such as polyethylene film or nonwoven. The sheet may also be a
laminate comprising at least two distinct layers. Laminates
suitable for packaging of hygiene articles are assumed to be known
to the person skilled in the art, and are not in any way limiting
for the present invention.
[0041] If desired, the sheet for forming a packaging unit according
to the present invention may be opaque in order to disguise the
contents of the packaging unit, which is particularly important if
the used article wrapped into the packaging unit of the present
invention cannot be disposed immediately after replacement.
Further, the sheet may comprise print, which may be beneficial for
attracting the user's attention and improving the user's mood.
[0042] The sheet of material forming a packaging unit according to
the present invention may comprise an odour-inhibiting or
odour-neutralising substance. Such a substance may be applied in
any suitable manner known to the person skilled in the art, e.g. as
coating, activatable microcapsules, impregnated patches or the
like.
[0043] It is conceivable that the sheet for forming a packaging
unit according to the present invention may be stretchable or
expandable, which may be advantageous if the hygiene article is
greatly deformed during use, and may thus be difficult to wrap
without deforming the packaging unit.
[0044] The packaging unit for hygiene articles according to the
present invention may is formed by a method comprising the steps
of: [0045] a) providing a sheet having an inner surface and an
outer surface, the inner surface comprising an edge zone comprising
an inner edge portion and an outer edge portion, the sheet having
two folding axes dividing the sheet into a first region, a second
region, and a third region; [0046] b) providing one of the inner
edge portion and the outer edge portion of the edge zone of the
second region with resealable adhesive, such that the other of the
inner edge portion and the outer edge portion of the edge zone of
the second region is adhesive-free; [0047] c) providing one of the
inner edge portion and the outer edge portion of the edge zone of
the first region and one of the inner edge portion and the outer
edge portion of the edge zone of the third region with resealable
adhesive in a complementary manner to the edge portion of the
second region being provided with resealable adhesive; such that a
chessboard pattern of resealable adhesive is formed along the edge
zone; and such that the other of the inner edge portion and the
outer edge portion of the edge zone of the first region and the
other of the inner edge portion and the outer edge portion of the
third region are adhesive-free; [0048] d) providing the
adhesive-free edge portion of the edge zone of the second region
with a release agent; [0049] e) folding the sheet about the first
folding axis, such that the edge portion carrying resealable
adhesive in the first region is brought in contact with the edge
portion carrying release agent in the second region; and the edge
portion carrying resealable adhesive in the second region is
brought in contact with the adhesive-free edge portion in the first
region; [0050] f) folding the sheet about the second folding axis,
such that the edge portion carrying resealable adhesive in the
third region is brought in contact with the outer surface of the
first region.
[0051] It should be noted that steps b) and c) may be performed
simultaneously. Further, step d) may be performed after step a),
thus giving an alternative method for forming a packaging unit for
hygiene articles according to the present invention, wherein the
method comprises the steps of: [0052] a) providing a sheet having
an inner surface and an outer surface, the inner surface comprising
an edge zone comprising an inner edge portion and an outer edge
portion, the sheet having two folding axes dividing the sheet into
a first region, a second region, and a third region; [0053] b)
providing one of the inner edge portion and the outer edge portion
of the edge zone of the second region with a release agent; [0054]
c) providing the other one of the inner edge portion and the outer
edge portion of the edge zone of the second region being free from
release agent with resealable adhesive; [0055] d) providing one of
the inner edge portion and the outer edge portion of the edge zone
of the first region and one of the inner edge portion and the outer
edge portion of the edge zone of the third region with resealable
adhesive in a complementary manner to the edge portion of the
second region being provided with resealable adhesive; such that a
chessboard pattern of resealable adhesive is formed along the edge
zone; and such that the other of the inner edge portion and the
outer edge portion of the edge zone of the first region and the
other of the inner edge portion and the outer edge portion of the
third region are adhesive-free; [0056] e) folding the sheet about
the first folding axis, such that the edge portion carrying
resealable adhesive in the first region is brought in contact with
the edge portion carrying release agent in the second region; and
the edge portion carrying resealable adhesive in the second region
is brought in contact with the adhesive-free edge portion in the
first region; [0057] f) folding the sheet about the second folding
axis, such that the edge portion carrying resealable adhesive in
the third region is brought in contact with the outer surface of
the first region.
[0058] It should be noted that steps c) and d) may be performed
simultaneously.
[0059] Consequently, when a packaging unit comprising two folding
axes is folded, the adhesive-covered edge portions of the first
region are brought into contact with the edge portions of the
second region carrying release agent, and the adhesive-covered
portions of the second region are brought into contact with the
adhesive-free portions of the first region, thus forming a pocket.
The subsequently folded third region is folded over the outer
surface of the first region and the adhesive-covered edge portions
of the third region are brought into contact with the adhesive-free
outer surface of the first region, thus forming a lid. The folding
order may be reversed, i.e. the adhesive-covered edge portions of
the second region are brought in contact with the adhesive-free
portions of the third region, and the adhesive-covered portions of
the third region are brought in contact with the portions of the
second region carrying the release agent. The lid may be formed by
folding the first region over the outer surface of the third
region. The adhesive pattern according to the present invention
thus has the advantage of giving the user the possibility to fold
the packaging unit in any order when resealing the packaging unit,
and still obtain a liquid- and odour-tight package, ensuring that
the used article is disposed of in a discrete and hygienic manner.
Further, when the packaging unit of the present invention is used
for disposal, the user may choose to roll the packaging unit
instead of folding it.
[0060] The present invention also relates to a web of material for
forming packaging units for hygiene articles, wherein the packaging
units are formed by cutting the web into sheets of appropriate
size. The web of material of the present invention has a
longitudinal direction running along a longitudinal central axis
and a transverse direction perpendicular to the longitudinal
direction, and comprises a plurality of transverse cutting zones
arranged along a respective central cutting axis running in the
transverse direction of the web. The transverse cutting zones are
positioned at a distance from each other in the longitudinal
direction of the web. Each of said transverse cutting zones
comprises a central portion and a first and a second peripheral
portion arranged on either side of the central portion in the
transverse direction. At least a section of the central portion of
each of the transverse cutting zones of the web is provided with a
release agent.
[0061] The release agent may be provided along the entire length of
the central portion of the transverse cutting zone, or may be
provided at a section of the central portion of the transverse
cutting zone, as described above.
[0062] Of course, each of the transverse cutting zones may be
provided with resealable adhesive in at least a section of the
transverse cutting zone being free from release agent, such that
the section provided with a resealable adhesive in the central
portion of the transverse cutting zone is displaced in the
longitudinal direction in relation to the sections provided with a
resealable adhesive in the first and the second peripheral portions
of the transverse cutting zone. In other words, a chessboard
pattern of resealable adhesive is formed along each of the
transverse cutting zones.
[0063] The web according to the present invention may be made of
any material suitable for manufacturing packaging units, i.e. a
plastic film, a nonwoven, a laminate, or any other material known
to the person skilled in the art.
[0064] The dimensions of a web of material of the present invention
may vary depending on the size of the packaging units to be
manufactured. Most typically, the web of material is in the form of
a roll having a length of several hundred meters in the
longitudinal direction, and a width in the transverse direction of
10-50 cm, preferably 15-40 cm, more preferably 20-30 cm.
[0065] The dimensions of the transverse cutting zone may vary
depending on the size of the packaging unit to be manufactured, and
on the adhesive strength required. The transverse cutting zone may
have a width in the longitudinal direction of the web of 0.5-5 cm,
preferably 1-4 cm, more preferably 2-3 cm. The length of the
transverse cutting zone in the transverse direction of the web
equals the width of the web of material in the transverse direction
of the web.
[0066] The present invention further relates to a manufacturing
method for providing a web of material for forming packaging units
for hygiene articles, comprising the steps of: [0067] a) providing
a web of material having a longitudinal direction running along a
longitudinal central axis and a transverse direction perpendicular
to the longitudinal direction, the web running in machine direction
(MD) such that the longitudinal direction of the web coincides with
the MD, the web comprising a plurality of transverse cutting zones,
each of the transverse cutting zones being arranged along a central
cutting axis running in the transverse direction of the web, the
transverse cutting zones being positioned at a distance from each
other in the longitudinal direction of the web; each of the
transverse cutting zones comprising a central portion and a first
and a second peripheral portion arranged on either side of the
central portion in the transverse direction of the web; [0068] b)
providing at least a section of the central portion of each of the
transverse cutting zones of the web with a release agent in the
transverse direction of the web; [0069] c) providing at least a
section of the remaining portion of each of the transverse cutting
zones of the web with resealable adhesive in the transverse
direction of the web; such that the section provided with a
resealable adhesive in the central portion of the transverse
cutting zone is displaced in the longitudinal direction in relation
to the sections provided with a resealable adhesive in the first
and the second peripheral portions of the transverse cutting zone;
[0070] d) cutting the web through the transverse cutting zones
along the central cutting axes.
[0071] Of course, steps b) and c) may be carried out in any order,
i.e. the web of material may first be provided with a resealable
adhesive, and then with the release agent on the sections of the
central portion of the transverse cutting zones being free from the
resealable adhesive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0072] Embodiments of the invention will now be described by way of
example only and with reference to the accompanying drawings, of
which:
[0073] FIG. 1 shows a packaging unit according to the present
invention;
[0074] FIG. 2 depicts the packaging unit depicted in FIG. 1 in a
folded state;
[0075] FIGS. 3 and 4 illustrate a web of material for manufacturing
packaging units according to the present invention;
[0076] FIG. 5 shows a graphic representation of the glue amount on
different samples of the packaging units;
[0077] FIG. 6 shows a graphic representation of the adhesive force
of the pocket of different samples of the packaging units;
[0078] FIG. 7 shows a graphic representation of the adhesive force
of the lid of different samples of the packaging units;
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0079] The packaging unit 1 depicted in FIG. 1 is a rectangular
sheet comprising a first folding axis 9 and a second folding axis
9' dividing the packaging unit into a first region 10, a second
region 11 and a third region 12. Each of the regions comprises an
inner edge portion 5, 5', 5'' and an outer edge portion 6, 6', 6''.
As shown in FIG. 1, the outer edge portions 6, 6'' of the first and
third regions respectively are provided with resealable adhesive 7,
while the inner edge portions 5, 5'' of the first and third regions
respectively are adhesive-free. The adhesive pattern of the second
region 11 is complementary to the adhesive pattern of the first and
third regions 10, 12, thus forming a chessboard pattern. In other
words, the inner edge portion 5' of the second region 11 is
provided with resealable adhesive 7, and the outer edge portion 6'
of the second region 11 is adhesive-free and is provided with a
release agent 22. This in turn means that, when the sheet is
e-folded about the first and second folding axes 9, 9' as shown in
FIG. 2, the outer edge portions 6 of the first region 10 or the
outer edge portions 6'' of the third region 12 carrying resealable
adhesive 7 are brought in contact with the outer edge portions 6'
carrying the release agent 22 in the second region 11, depending on
which of the first and the third regions 10, 12 is brought in
contact with the second region 11. Consequently, the inner edge
portions 5' carrying resealable adhesive 7 in the second region 11
are brought into contact with the adhesive-free inner edge portions
5 of the first region 10 or the adhesive-free inner edge portions
5'' of the third region 12. As can be seen from FIG. 2, the width
of the sealing area corresponds to the sum of the widths of the
adhesive portions 5', 6. It should be noted that the order in which
the packaging unit is folded is irrelevant. For example, the
packaging unit may be folded around the second folding axis 9',
bringing the third region 12 in contact with the second region 11,
sealing the outer edge portions 6'', 6' and the inner edge portions
5'', 5' and forming a pocket. The packaging unit is subsequently
folded around the first folding axis 9, bringing the first region
10 in contact with the outer surface of the third region 12, thus
forming a lid and sealing the packaging unit (FIG. 2). The folding
order may also be reversed. This is a great advantage, since when
the packaging unit of the present invention is used for disposal,
the user does not have to fold the packaging unit in any particular
order to be able to obtain a tightly sealed package. The packaging
unit will provide a tight and hygienic package regardless of the
folding order. Also, the user may choose to roll the packaging unit
rather than folding it.
[0080] The packaging unit depicted in FIG. 1, wherein the release
agent is provided in the edge zone of the second region only, has
the advantage of having an optimal adhesive strength and
reclosability, which will be discussed in greater detail below.
[0081] In order to obtain a tight package, the transverse edges 4'
and 4* of the packaging unit 1 are provided with resealable
adhesive 7. When both transverse edges 4' and 4* are provided with
adhesive, the folding order is irrelevant, as described above. It
is also conceivable to provide only one of the transverse edges 4',
4* with resealable adhesive 7. In this case, the folding must be
initiated around the folding axis being positioned closest to the
adhesive-free transverse edge, such that the region comprising the
adhesive-covered transverse edge portion forms a lid and such that
the resealable adhesive positioned at the transverse edge portion
seals the packaging unit.
[0082] In order to facilitate the opening of the package, the
adhesive-covered portions may be positioned such that at least one
of the corner portions 21 of the packaging unit 1 is adhesive-free,
thus forming a gripping tab that is gripped by the user upon
opening the package. Moreover, the adhesive-free corner portion 21
serves as an evacuation opening when the packaging unit is sealed
(FIG. 2).
[0083] FIG. 3 depicts a web of material 501 suitable for
manufacturing packaging units according to the present invention
after step b) of the manufacturing method for providing a web of
material for forming packaging units for hygiene articles. The web
of material has a longitudinal direction running along a
longitudinal central axis 508 and a transverse direction
perpendicular to the longitudinal direction. The web 501 comprises
a plurality of transverse cutting zones 502, each being arranged
along a respective central cutting axis 503 running in the
transverse direction of the web. The transverse cutting zones 502
are positioned at a distance from each other in the longitudinal
direction of the web 501. Each of the transverse cutting zones
comprises a central portion 505 and a first and a second peripheral
portion 504, 504' arranged on either side of the central portion
505 in the transverse direction of the web. As shown in FIG. 3, the
central portion 505 of the transverse cutting zone 502 is provided
with a release agent.
[0084] FIG. 4 illustrates the web of material 501 after the
resealable adhesive has been applied to the web of material 501,
i.e. after step c) of the manufacturing method for providing a web
of material for forming packaging units for hygiene articles. The
web of material 501 is provided with resealable adhesive in
sections of the transverse cutting zone 602 being free from release
agent, such that a chessboard pattern of is formed in a manner
described above. Thus, section 511 of the central portion 505 of
the transverse cutting zone 502, as well as sections 506 and 506'
of the first and the second peripheral portions 504, 504' of the
transverse cutting zone 502 are provided with adhesive. When the
web of material 501 is cut along the central cutting axes 503, the
packaging units similar to the ones depicted in FIG. 1 are
formed.
[0085] Method for Measuring the Adhesive Force of the Packaging
Unit
[0086] The method is intended to determine the force required to
open the packaging unit when the edge portions described above have
been sealed by means of the resealable adhesive. Adhesive force is
specified as the Average Load between Extension Limits, the force
required to separate glue-to-release agent or glue-to-material of a
packaging unit. Measurements have been made both on newly produced
and aged packaging units.
Equipment
[0087] Tensile tester, 20 N load cell, crosshead speed 500
mm/min
TABLE-US-00001 [0087] Distance between clamps 25 mm Crosshead
movement 80 mm Clamps for tensile tester 60 mm wide The calculation
of Average Load between Extension 15-65 mm Limits from the tensile
curve is done between
[0088] Heat cupboard 40.+-.3.degree. C. [0089] Pieces of paper,
approx. 60.times.30 mm. [0090] Double-sided tape, approx. 5 mm
wide.
[0091] Sample Preparation
[0092] The adhesive must be allowed to stabilize before the tests
are conducted. [0093] For measurements on newly produced samples,
the samples should be stored for at least one week from the
production occasion at room temperature. [0094] Alternatively, for
measurement on newly produced samples, the samples should be stored
for 24.+-.1 hours in a heat cupboard at 40.degree. C. The samples
should be allowed to acclimatize to the ambient temperature for at
least one hour prior to measurements. [0095] Aging is simulated by
storing the samples in a heat cupboard at 40.degree. C. for four
weeks; analogous to the above, the samples should be allowed to
acclimatize to the ambient temperature for at least one hour prior
to measurements.
[0096] Procedure
[0097] The pre-tension is between -0.100 N and +0.100 N in both
pull tests.
[0098] Pull 1, testing of the first product opening, i.e. opening
of the region forming the lid according to the above: [0099] Put
double-sided tape along one of the longitudinal edges of a piece of
paper; [0100] Attach the tape carrying the piece of paper to the
inner surface of the packaging unit at the central portion of the
transverse edge; [0101] Center and secure the product in the lower
clamp. Secure the piece of paper in the upper clamp; [0102] If
necessary, adjust the pre-tension to the correct level by changing
the position of the piece of paper in the clamp; [0103] Perform
Pull 1 test.
[0104] Pull 2, testing of the second product opening, i.e. opening
of the region forming the pocket according to the above: [0105]
Open the remaining section of the lid such that the packaging unit
is unfolded around the second folding axis, and fold the lid such
that the transverse edge of the lid is parallel to the second
folding axis; [0106] Insert the folded lid of the packaging unit
and the hygiene article arranged inside the packaging unit into the
lower clamp, such that the upper edge of the lower clamp is aligned
with the second folding axis, and secure it; [0107] Open the
transverse adhesive seam of the packaging unit only up to the
remaining glued seams in the second and third regions of the
packaging unit; [0108] Secure the released transverse edge of the
packaging unit in the upper clamp without securing any part of the
hygiene article; [0109] Adjust the pre-tension; e.g. by manually
folding away the sections of the secured product that press against
the upper clamping yoke; [0110] Perform Pull 2 test.
[0111] Method for Measuring Reclosability
[0112] This method relates to visual evaluation of how many
packaging units remain sealed after a given time interval from the
occasion of placing a used hygiene article in the packaging unit
and sealing the edge portions. A dark-colored (black) cylinder is
placed in the packaging unit and the edge portions are sealed by a
pressing unit. The samples are checked visually after a given time,
and the number and/or percentage of samples that are still sealed
is reported.
[0113] Equipment [0114] Foam cylinders made of polyurethane foam,
with outer diameter=25 mm, and length=60 mm [0115] Timer, accuracy
.+-.0.3 sec [0116] Pressing unit equipped with: [0117] Pressing
plate, 50.times.25 mm .+-.0.5 mm; [0118] Anvil, 70.times.25 mm
.+-.0.5 mm [0119] Plate and anvil covered with foam and Teflon
tape. [0120] Pressure force 100 N .+-.5 N [0121] Pressing time 3
seconds .+-.1 sec [0122] Stretching tool, each fork pin being
8.times.1.5 mm .+-.1 mm [0123] Digital dynamometer with load cell
>100 N, type Mecmesin AFTI or equivalent
[0124] Procedure
[0125] Before the test starts, check that the pressure force as
well as pressure time of the pressing unit is according to the
specifications.
[0126] It is recommended to test 75 samples in each sample group.
[0127] Gently open the packaging unit, remove the hygiene article,
and make sure that the packaging unit is not damaged. Gently spread
out the packaging unit on a flat surface making sure that the
packaging unit doesn't wrinkle. [0128] Place the cylinder at the
transverse edge of the packaging unit. Make sure that the cylinder
is placed at the same transverse edge for all the samples. [0129]
Wrap the cylinder in the packaging unit by rolling the cylinder,
making sure that the longitudinal edge portions do not wrinkle or
fold. Perform this step on all the samples before sealing the
edges. [0130] Divide the samples into 5 samples groups. [0131]
Place the tip of the fork pins of the stretching tool inside the
opening formed at one of the transverse edges of the packaging
unit. [0132] Stretch out as many of the wrinkles as possible, and
pre-seal the opening by manually gently pressing the transverse
edges together. [0133] Repeat the procedure on the other transverse
edge of the packaging unit. [0134] Place one of the pre-sealed
transverse edges between the pressing plates. It is desirable to
press as much of the packaging unit material as possible without
squeezing the foam cylinder inside. The transverse edge of the
packaging unit should at maximum be aligned with the inner edge of
the pressing plate. [0135] Press the start button and wait until
the pressing unit has performed one complete cycle. Turn around the
sample immediately and seal the other transverse edge.
[0136] Start a timer set to 10 minutes (tolerance -1/+2 min). After
10 minutes check the status of the sealed edges. The status is
checked according to the following procedure: [0137] Lift each of
the samples and inspect both transverse edges by slightly twisting
and turning the sample around. Be careful not to disturb the sealed
edges. [0138] If the cylinder is visible at any of the transverse
edges when making a quick overview, the sample is considered to be
open and is rejected from further inspection. [0139] Note the
result, replace the sample at the table and start a timer set to 50
minutes (tolerance .+-.5 min). Repeat the 60 minutes status check
of the sealed edges, discard the samples that are already open.
[0140] Report the number of samples that remained closed after 10
and 60 minutes versus the number of tested samples. [0141]
Calculate the amount of closed samples in percentage (%), by whole
numbers
[0141] % = Samples closed Samples total 100 ##EQU00001##
[0142] Results
[0143] All the samples have the chess-board adhesive pattern
depicted in FIG. 1. The amount of adhesive is varied in the
different regions. Thus, in the first region 10 and the third
region 12, the adhesive amount at the outer edge portions 6 and 6''
is 18 gsm, while the adhesive amount is 10 gsm at the inner edge
portions 5' of the second region, and 20 gsm at the transverse edge
portions 4' and 4*. The total amount of adhesive does not differ
significantly between different samples (FIG. 5). Hence, the
adhesive amount should not influence the adhesive force or
reclosability results.
[0144] In the reference samples the packaging unit is free from
release agent. In the samples S1-S3, the outer edge portion 6' in
the second region 11 is provided with release agent. The area of
the outer edge portion 6' of the second region 11 being provided
with release agent is 25% in sample S1, 60% in S2, and 75% in
S3.
[0145] Pull 1
[0146] The release agent added to S1-S3 should not influence the
adhesive force of the lid, since the release agent applied at the
inner surface of the second region does not affect the adhesive
force between the adhesive in the third region and the outer
surface of the first region of the packaging unit.
[0147] The results, shown in FIG. 6, confirm this assumption, even
though there are some differences within each of the groups of
samples, which most likely depend on migration of the adhesive.
[0148] Pull 2
[0149] The release agent added to S1-S3 should influence the
adhesive force of the pocket. The release agent arranged at the
outer edge portions 6' in the second region will be in contact with
the adhesive at the outer edge portions 6 in the first region, or
the adhesive at the outer edge portion 6'' in the third region,
depending on whether the packaging unit is folded around the first
or the second folding axis.
[0150] Further, it is assumed that the adhesive force of the lid is
somewhat lower compared to the adhesive force of the pocket, given
the fact that the pocket is formed by adhering two edge portions
carrying resalable adhesive, wherein the adhesive edge portion will
be positioned adjacent to each other when the packaging unit is
folded, while the lid is formed by adhering only one edge portion
carrying adhesive. As was mentioned above, the adhesive strength of
the adhesively sealed seam depends on the total width of the
adhesive seam, which in turn is a sum of the widths of the adjacent
adhesive-carrying edge portions.
[0151] The results are depicted in FIG. 7, wherein it is clearly
seen that the reference samples has the highest adhesive force,
while samples S1-S3 show a significantly lower adhesive force.
Analogous with the values in Pull 1-tests, the major contributor to
variations within each of the groups of samples is probably
adhesive migration. Also, when comparing the results shown in FIGS.
6 and 7, it may be seen that the adhesive force of the pocket is
higher than the adhesive force of the lid, in line with the
assumption above. As mentioned earlier, it is desirable to provide
a packaging unit having the values of adhesive forces of the lid
and the pocket as close to each other as possible, such that the
opening of the packaging unit is perceived as smooth and even by
the user.
TABLE-US-00002 TABLE 1 Silicone Adhesive force (N) Reclosability
(%) Adhesive Sample area (%) Pull 1 Pull 2 10 min 1 h weight (g)
Ref 0 0.72 3.38 60 44 0.071 S1 25 0.75 1.92 60 36 0.069 S2 60 0.70
2.11 88 28 0.070 S3 75 0.62 2.00 80 64 0.070
[0152] As may be seen in Table 1, the Pull 1 values, indicating the
adhesive strength of the lid, are substantially the same for all
the samples, which confirms the assumption that the release agent
arranged at the inner surface of the second region does not affect
the adhesive strength of the lid being attached to the outer
surface of one of the first and the third regions, as discussed
above.
[0153] Pull 2 values shown in Table 1 clearly indicate that the
adhesive strength of the pocket, i.e. adhesive strength between the
inner surface of the edge portion of the second region and the
inner surface of the edge portion of one of the first and the third
regions, is significantly lower for samples S1-S3 compared to the
reference samples. The conclusion that may be drawn from these
results is that the addition of the release agent to one of the
edge portions of the second region lowers the adhesive force of the
pocket, which in turn facilitates opening of the pocket. Moreover,
since the adhesive force of the lid (Pull 1) and the adhesive force
of the pocket (Pull 2) do not differ as much in samples S1-S3 as in
the reference samples, the opening of the packaging unit is
perceived by the user as being even and smooth.
[0154] Another important factor to consider when assessing the
adhesive force of the pocket and the lid is reclosability, i.e. the
ability of the packaging unit to become and remain sealed after the
user has placed a used hygiene article in the packaging unit. As
may be seen in
[0155] Table 1, 60% of the reference and S1-samples remained sealed
after 10 min. A significantly higher fraction of samples S2 and S3
remained sealed after 10 min, 88% and 80%, respectively. A possible
explanation of this result is that the addition of a higher amount
of release agent prevents migration of the adhesive, which means
that the adhesive remains in its original position when the
packaging unit is opened for the first time, rather than being
transferred to the surfaces being in contact with the adhesive when
the packaging unit is sealed. Such a transfer of the adhesive
causes an uneven distribution of the adhesive, which in turn
deteriorate reclosability.
[0156] Comparing now the reclosability results for 1 h, it may be
concluded that the addition of the highest amount of release agent
provides the best results regarding the ability of the resealed
packaging unit to remain sealed. Thus, 64% of samples S3 remained
sealed after 1 h, compared to 44% for the reference samples, 36%
for S1 and 28% for S2. This confirms the assumption that the higher
amount of the release prevents adhesive migration thus improving
reclosability.
[0157] Although the present invention has been described with
reference to various embodiments, those skilled in the art will
recognise that changes may be made without departing from the scope
of the invention. It is intended that the detailed description be
regarded as illustrative and that the appended claims including all
the equivalents are intended to define the scope of the
invention.
* * * * *