Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND METHOD FOR RUPTURING
ENCAPSULATED ADHESIVE IN SHEET MEDIA
Background of the Invention
Field of the Invention
[0001] The present invention relates to a system and method for rupturing
an encapsulated adhesive in a sheet media, such as an adhesive in a roll
product. The
system can further optionally include a printer for placing indicia on the
sheet, a feeder for
feeding the sheet, a cutter for cutting the roll product into discrete sheets
and a label
applicator for applying the discrete sheet to a desired product. This system
can utilize a
fixed, inclined activation blade which extends across the sheet media to
rupture and/or
spread the encapsulated media. Alternatively, a single crushing roller, a pair
of crushing
rollers or a series of crushing rollers can be used to rupture the
encapsulated media. This
roller or rollers can be used with or without the activation blade and can be
eccentrically
rotatable discs.
Description of the Background Art
[0002] Currently, it is known to place encapsulated adhesives on a sheet
media. For example, a sheet of paper can have microdots or microlines with an
adhesive
as disclosed in U.S. Patent 4,961,811. When it is desired to expose this
adhesive, the
encapsulated adhesive can be ruptured by applying pressure such as from a coin
or
fingernail. Other encapsulated adhesives are known which can be ruptured by
exposure
to heat.
[0003] However, there exists a need in the art for a system and method for
rupturing an adhesive in a sheet media, which can work on a large scale. In
other words,
a system and method for mass producing a series of sheets which have their
encapsulated adhesives ruptured are needed. Such a system and method can be
used to
supply ready to adhere labels for products. Other uses are also contemplated.
Such a
system and method should be reliable and of low costs and low need for
maintenance.
Summary of the Invention
(0004] Accordingly, it is an object of the invention to provide a system
which can reliably rupture encapsulated adhesives contained in a sheet media.
[0005] A further object of the invention is to provide a method for reliably
rupturing encapsulated adhesives contained in a sheet media.
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[0006] It is a further object of the invention to provide such a system and
method which can be used on a large scale to quickly provide application-ready
labels
and other adherable products.
[0007] Yet another object of this invention is to provide a low cost and low
maintenance system and method.
[0008] These and other objects of the present invention are fulfilled by a
system for rupturing an encapsulated adhesive contained in sheet media,
comprising a
feeder for the sheet media and an activation device for releasing the
encapsulated
adhesive as the sheet media is moved past the device by the feeder.
[0009] Additionally, these and other objects are fulfilled by a method for
rupturing an encapsulated adhesive contained in sheet media, comprising the
steps of
providing a sheet media, feeding the sheet media along a travel path, passing
the sheet
media against an activation device, and rupturing the encapsulated adhesive as
the sheet
media moves past the activation device.
[0010] Further scope of the applicability of the present invention will
become apparent from the detailed description given hereinafter. However, it
should be
understood that the detailed description and specific examples, while
indicating preferred
embodiments of the invention, are given by way of illustration only, since
various changes
and modifications within the spirit and scope of the invention will become
apparent to
those skilled in the art from this detailed description.
Brief Description of the Drawings
[0011] The present invention will become more fully understood from the
detailed description given hereinbelow and the accompanying drawings which are
given
by way of illustration only, and thus are not limitative of the present
invention, and
wherein:
[0012] Figure 1 is a schematic view of a first embodiment of the
encapsulated adhesive rupturing system of the present invention;
[0013] Figure 2 is an enlarged view of Figure 1 showing a detail of a
portion of the system of the present invention;
[0014] Figure 3 is a schematic view of a second embodiment of the
system of the present invention;
[0015] Figure 4 is a schematic view of a third embodiment of the system of
the present invention;
[0016] Figure 5 is a side view of a set of crushing rollers used in a fourth
embodiment of the present invention;
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[ 0017 ] Figure 6 is a perspective view of the set of crushing rollers of the
fourth embodiment as shown in Figure 5;
[0018] Figure 7 is a view similar to Figure 6, but showing the crushing
rollers in a rest position;
0019 ] Figure 8 is a schematic view showing a series of sets of crushing
rollers used in a fifth embodiment of the present invention; and
[0020] Figure 9 is a perspective view of a second embodiment of a disc
used in the crushing roller of the present invention.
Detailed Description of the Preferred Embodiments
[0021] Referring in detail to the drawings and with particular reference to
Figure 1, a first embodiment of a system 10 for rupturing an encapsulated
adhesive
contained in sheet media 12 is disclosed. While a web 14 of sheet media is
disclosed, it
should be understood that any form of media could be used. For example, a
supply of
individual sheets could instead be used. Moreover, many different types of
sheet media
can be used. For example, paper, metal foil, plastic sheets or any other
desired sheet
could be used.
0022 ] Downstream from web 14, a label printer 16 is provided. This
printer 16 will place indicia on the sheet media. Of course, this printer 16
could be omitted
and the indicia preprinted on the sheet media if so desired. A roller 18 is
shown between
web 14 and printer 16. This roller diverts the direction of movement of the
sheet media.
While not shown, some motor or other driver can be used for unwinding and/or
moving
the sheet media 12 through the system 10. The web 14 and driver rollers 20 are
contemplated as being a part of the feeder 22 of the system 10. While a pair
of drive
rollers 20 on opposite sides of the sheet media have been shown, the form and
positioning of this drive could of course be varied.
[0023] Upstream from drive rollers 22, an activation unit 24 is shown. In
this embodiment, the activation unit 24 includes a pair of pressure or
crushing rollers 26,
an activator blade 28 and a support surface 30. The activation unit 24 is not
limited to
these elements, but in the first embodiment this unit will at least include
the activator
blade 28 and the crushing rollers 26.
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[0024] By using both the pressure rollers 26 and activation blade 28, it can
be ensured that the encapsulated adhesives contained in the sheet media 12 are
ruptured. It is contemplated that the majority of rupturing of the
encapsulated adhesives
will be accomplished by the pressure rollers 26. However, in the first
embodiment, some
rupturing of the adhesives can also be carried out via the activator blade 28.
Apart from
rupturing any remaining unruptured encapsulated adhesives, this activator
blade 28
serves to spread the adhesives around the sheet media 12. This will help
adherence of
the label or the product prepared from the sheet media, as will be discussed
below.
[0025] It is also contemplated that, instead of using the pressure rollers 26
the activator blade 28 could instead be used alone. The force exerted by the
activator
blade would be greater than the force used when both pressure rollers 26 and.
an
activator blade 28 are used. Nonetheless, it is contemplated that an activator
blade alone
could be used. However, it is important that the pressure exerted by this
activator blade
not be so great as to mar the sheet media. In addition, instead of a single
blade 28, a
series of blades could be used.
[0026] As seen in the drawings, this blade 28 extends across the width of
the sheet media and forms an acute angle 32 with an upstream position of the
sheet
media 12 as seen also in Figure 2. It should be noted in Figure 2 that the
support surface
30' is a flat surface instead of the roller 30 shown in Figure 1. Other
surfaces could be
used as desired. The sheet media 12 will move along a travel path 34 which is
adjacent
crushing rollers 26 and activator blade 28. As the sheet media passes through
the
activation unit 24, the microencapsulated adhesive in the sheet media 12 will
be ruptured.
Any type of suitable adhesive can be used in the sheet media.
[0027] The adhesives may be classified according to the mode of
reactivation, by the extent of encapsulation, chemical composition, whether
solvent-
based, or reactive or curable. The entire adhesive can be encapsulated or a
component
could be encapsulated. Solvent-based systems are reactivated by applying
pressure and
releasing the capsule contents to tackify the adhesive. Adhesives such as
polyvinyl
acetate, rubber, nitrite rubber, ethylcellulose, or other cellulose
derivatives such as
cellulose acetate lend themselves to solvent reactivation. While the capsules
are intact,
the coating is dry to the touch. The coating is tackified upon rupture and
release of the
solvent. Such systems are taught for example in U.S. Patent No. 2,907,682.
Reactive
resins can also be encapsulated. These could include materials such as epoxy,
isocyanates, polyesters, polyacrylates, glycidyl acrylates, acrylic nitrite
and methacrylates
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with curing agents such as azo initators, benzoyl peroxide, acid chorides or
cross linking
agents such as melamine formaldehyde and other materials.
[0028 The capsules can be assembled with the curing agents adhered to
the outside of the capsule wall or adhered to the surface upon which the
capsules are
adhered. Examples of various adhesive systems include U.S. Patent Nos.
3,996,308,
4,980,410, 4,808,639 and 3,725,501. More recently, encapsulated adhesives have
been
developed that form in situ in the microcapsules during the capsule formation
process.
These adhesives are based on acrylate or methacrylate type monomers. Such
capsules
for example are taught in U.S. Provisional Application No. 60/230,365 filed
September 6,
2000, the entire contents of which are hereby incorporated by reference. These
adhesives are also dry to the touch. Upon capsule rupture, the tacky adhesive
in the
capsules is made available for bonding. The in situ microencapsulated
adhesives,
although preferred, should not be, viewed as limiting of the device of the
invention which
can be utilized with the various microencapsulated adhesives.
[0029 The activator blade 28 is at a fixed position relative to travel path 34
as well as relative to a point on the support surfaces 30 and 30'. While
roller 30 may be
rotatable, the blade 28 is nonetheless at a fixed location relative to an axis
of the roller. Of
course, this roller 30 could also be non-rotatable if so desired.
[00307 The activator blade 28 is shown extending across all of the width of
the sheet media 12 and is shown as having a linear edge 35. Of course, this
blade could
be only across half or a majority of the sheet. In fact, the blade 28 could
only extend
along a small width of the sheet media or could form some pattern across the
width of the
sheet media, for example, a comb-like, saw toothed pattern or curved pattern.
Alternatively, the activator blade 28 could have staggered contact points with
the sheet
media. For example, if the blade 28 had a comb-like pattern, some teeth could
be
positioned further upstream or downstream relative to other teeth. Any number
of patterns
and placements could be had for the point or points of contact of the blade 28
with the
sheet media 12. Nonetheless, this blade 28 should be at a fixed position to
enable
uniform, constant rupturing of the adhesive if it is used with crushing
rollers 26.
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[0031] If, however, a label is to be formed and adhesive is not needed at
the periphery of the label, some reciprocating mechanism can be provided to
repeatedly
engage and disengage at least one of the rollers 26 and the blade 28 with the
sheet 12 to
form the desired pattern of ruptured encapsulated adhesive. It should
therefore be
appreciated that a great variety of designs or patterns can be formed with the
ruptured
adhesives, but the system 10 nonetheless enables mass production of ruptured
adhesives on sheet material.
0032 ] The crushing rollers 26 and activator blade 28 each exert a uniform
pressure on the sheet media 12 in order to rupture encapsulated adhesive on
the sheet
media. The pressure applied is sufficient to break the capsules without
damaging the
sheet media. No wastes or adhesives build up at the activator blade 28 so that
is does
not need to act as a doctor blade. Continual long-term running of the system
10 is
therefore possible. Not only will the blade 28 shear off the tops of
unruptured adhesive
capsules, but it will also spread or smear the adhesives on the sheet media
12.
( 0033 ] Downstream from activation unit 24 and drive rollers 20, a cutter 36
is provided as shown in Figure 1. -This cutter 36 can be a reciprocable
cutting blade or a
roller with a cutting blade or any other suitable cutter. The cutter 36 can
completely sever
the sheet or can only partially cut or perforate the sheet as desired. In the
embodiment
shown, the cutter 36 is provided on both sides of the sheet media, but it
could include a
blade or knife only on one side of the sheet if so desired. If sheets are
being fed through
the system rather than a web of material, this cutter 36 can be omitted or
simply shut off.
[0034] A label applicator 38 is then provided downstream from the cutter
36. This applicator includes a pivoting arm 40 for applying labels to a side
of boxes 42.
These labels include the severed sheet media with indicia 44 on one side and
adhesive
on the other side. The adhesive adheres the label 46 to the box 42.
[0035] The boxes 42 are fed along conveyor 48. A suitable control means
(not shown) is provided for timing and controlling the overall operation of
the system 10.
[0036] Turning now to Figure 3, a third embodiment of the system of the
present invention is shown. In this embodiment, a web 14 of sheet material 12
is
provided. As with the first embodiment, a motor or other suitable drive can be
utilized to
unwind the sheet material 12 from the web. The activation unit 24 includes a
pair of
crushing rollers 26. Unlike the first embodiment, the crushing rollers shown
in this second
embodiment are a different size. In particular there is a smaller first
crushing roller 50 and
a larger second crushing roller 52. Between these crushing rollers, a crushing
nip 54 is
formed. While the larger second roller 52 is shown as being hollow, this is
merely a
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schematic showing. This roller 52 can be hollow or can be solid as desired.
Moreover, the
exact sizes of the rollers 26 can be varied as desired. Nonetheless, these
rollers 52, 54
will place a suitable pressure on the sheet media 12 in order to rupture the
encapsulated
adhesive. Then the activator blade 28 can smear or spread the adhesives. If so
desired, a
sufficient pressure can be provided by this activator blade 28 such that the
encapsulated
adhesives which are not ruptured by the crushing rollers 26 will be ruptured
by blade 28.
The activator blade 28 can sever the encapsulated adhesives or can provide
sufficient
force to crush the non-ruptured adhesives.
[0037] Downstream from the activator blade 28 is a drive nip 56. A roller
58 and the second crushing roller 52 will form this drive nip. The second
crushing roller
52 and/or the roller 58 can be powered in order to feed the sheet media 12
through the
system. A drive for unwinding web 14 can be omitted if so desired. Other
drives, apart
from nip 56, can be utilized if so desired. Since the adhesive will be
activated downstream
from the activator blade 28, the roller 58 can be coated in order to avoid
adhesives
adhering thereto.
[0038] Downstream from the drive nip 56 is a cutter 36. The comments
made with regard to the cutter 36 in the first embodiment are equally
applicable to the
cutter used in this and subsequent embodiments. The cutter 36 will sever the
sheet
media 12 in order to form individual sheets. The web 14 of sheet media can
have
preprinted labels. Therefore, upon severing by the cutter' 36, a label 46 will
be formed by
the individual sheets. While not shown, this second embodiment _ as well as
other
embodiments can have a label applicator 38. This applicator 38 can include a
pivoting
arm 40 for adhering the labels to boxes or other items. Conveyors, skids or
other suitable
devices for infeeding or outfeeding the items for labeling can also be
utilized.
[0039] Turning now to Figure 4, a third embodiment of the system of the
present invention is shown. Similarly to the previously described embodiments,
a web 14
of sheet material 12 is provided. Unlike the arrangement in Figure 3, it is
contemplated
that the sheet media 12 in web 14 will not be preprinted. Therefore, a
downstream printer
60 is utilized. This positioning of the printer in Figure 4 differs from the
printer 16 of Figure
1. It should be appreciated that the printer 16 and/or 60 could be upstream
and/or
downstream from the activation unit 24 as desired.
[0040] While a roller 58 is not shown in Figure 4 adjacent the second
crushing roller 52, such a roller could be utilized if so desired. Any
suitable drive for
feeding the sheet media 12 through the system can be utilized.
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[0041] Downstream from the printer 60 are a pair of guide rollers 52.
These rollers 62 guide the sheet media to the cutter 36. From the cutter 36, a
discharger
64 is shown. This discharger 64 can include a powered conveyor belt which will
feed the
severed labels from the cutter to the downstream location. As has been noted
above, a
label applicator and/or other suitable handling device can be provided.
[ 0042 ] Turning now to the fourth embodiment shown in Figures 5-7, a
plurality of discs 66 are utilized. These discs 66 are rotatable on axle 68 in
a
counterclockwise direction as indicated by the arrow 70 shown in Figure 6.
While a
counterclockwise rotation is indicated, a clockwise rotation could also be
utilized. A
suitable motor is provided for driving the axle 68. As the axle 68 rotates,
frictional
engagement will cause the disc 66 to rotate. As seen in Figure 6, these discs
are
eccentrically mounted such that they rotate in a non-uniform manner about the
axle 68.
This provides for different contact positions of the discs 66 along a width
and length of the
sheet media 12. The sheet media is fed in the direction indicated by arrow 72.
Of course,
the sheet media 12 could be fed in the opposite direction. While not shown, a
backing
roller, backing surface or other suitable device can be provided such that the
sheet media
12 moves between this surface and the rotating discs 66.
[0043] Upon contact with the sheet media 12, the discs 66 will rupture the
encapsulated adhesive. In this manner, a dispersed arrangement of released
adhesives
are provided on the sheet media 12.
[0044] Between the various discs 66, spacers 74 are provided. Any
suitably sized spacers and discs can be used. It is contemplated that the
spacers 74 will
not be eccentrically mounted on the axle 68. However, such eccentric mounting
could
also be carried out. The discs 66 will frictionally engage the rotating axle
68 in order to
undergo rotation. Upon stopping of rotation of the axle 68, the discs 66 will
fall by gravity
to a rest position. This position is shown in both Figures 5 and 7. In this
rest position 76,
the discs 66 are out of contact with the sheet media 12. Therefore, when the
system of
the present invention is shut off, the discs will move out of contact with the
sheet media.
Therefore, the ruptured adhesive will not have a chance to set up and adhere
to the discs
if the system is shut down for a long time.
[0045] While frictional engagement between the discs 66 and the axle 68
is contemplated, any other suitable arrangement can be had. For example,
gearing or
other known connectors may be provided. Moreover, the discs 66 may be
permanently
affixed to the axle 68 and a driver or other means can be provided in order to
move the
axle and its discs 66 away from the sheet media when the system is turned off.
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Nonetheless, a less complicated arrangement is provided by the design shown in
Figure
6. As noted above, when the system is shut down, the discs 66 will simply fall
by gravity
into their rest position 76. In this rest position 76, the discs 66 as well as
the spacers 74
are spaced from and out of contact with the sheet media 12.
(0046] Turning now fio Figure 8, a system similar to that shown in Figure
5-7 is also shown. In this system, two sets of crushing rollers 26 are
provided. In
particular, an axle 68 with the plurality of discs 66 and spacers 74 are
provided in each
set of crushing rollers 26. Similarly to the embodiment of Figure 6, these
discs 66 are
eccentrically mounted and upon rotation of the different axles 68, the discs
will spin in
order to engage the sheet media. This engagement will rupture the encapsulated
adhesives. The two sets of crushing rollers 26 are spaced and timed such that
a greater
amount of encapsulated adhesives are ruptured than is done in the embodiment
of
Figures 5-7. In fact, more than two sets of crushing rollers 26 can be
provided. The set of
crushing rollers 26 can be timed and spaced such that the complete width or a
majority of
the width of the sheet media 12 have the encapsulated adhesives ruptured.
[0047] In Figure 8, an activator blade 28 is shown downstream from the
crushing rollers 26. While such an activator blade is not shown in the early
embodiments
of Figures 5-7, it is contemplated that it can be included if so desired. A
separate support
surface 30 is utilized in Figure 8. If so desired, the activator blade 28 can
engage the
sheet media 12 as the sheet media is on the support 78. This support 78
supports .the
sheet media 12 as it moves past the sets of crushing rollers 26. It is
contemplated that,
upon termination of rotation of the axles 68, the discs 66 will fall to the
rest position 76 by
gravity.
[0048] Turning now to Figure 9, a modified form of the discs 66 is shown.
In particular, these discs 66 have flared edges 80. These flared edges are
designed to
reduce the distance between the discs 66. The spacers 74 in the prior
described
embodiments will cause some spaces between the contact area of the disc 66
with the
sheet media 12. In these spaces on the sheet media 12, the adhesives will not
be
activated. These flared edges will increase the contact area of the disc 66
with the sheet
media 12 and therefore increase the amount of ruptured encapsulated adhesives.
If so
desired, the spacers 74 can be omitted or of such a small size that the discs
66 will
substantially work across the entire width or a majority of the width of the
sheet media 12.
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[0049] With any of the different described systems of the present
invention, a method for rupturing an encapsulated adhesive contained in sheet
media is
provided. In this method, the sheet media 12 is provided. The sheet media 12
is then fed
along the travel path 34. The sheet media will pass an activation device. This
activation
device includes the activation unit 24. In the activation unit 24, a pair of
crushing rollers or
a single crushing roller can be provided. An activator blade 28 can be
provided to also
rupture encapsulated adhesives or to just simply smear the already ruptured
adhesives
on the sheet media. Alternatively, it is also possible to simply use the
activator blade 28
alone as the unit for rupturing the encapsulated adhesives. As described above
with
reference to the embodiments beginning with Figure 5, a series of rotatable
discs 66 an
also be used as the activation device. Either a single set of discs or a
plurality of sets of
discs can be utilized. With either of these arrangements, an activator blade
28 can be
used or omitted as described above. After the sheet media is passed against
'the
activation device 24, the encapsulated adhesives of the sheet media will be
ruptured as
has been described above.
[0050] The system and method of the present invention mass produces a
series of labels or sheets, which have an adhesive ready for use. The
activating unit 24
reliably and consistently provides for a useable adhesive by rupturing the
microencapsulated adhesives provided in sheet media 12. This system is
relatively low
cost and easy to maintain.
The invention being thus described, it will be obvious that the same may be
varied
in many ways. Such variations are not to be regarded as a departure from the
spirit and
scope of the invention, and all such modifications as would be obvious to one
skilled in
the art are intended to be included within the scope. of the following claims.
