U.S. patent application number 10/879382 was filed with the patent office on 2005-12-29 for laser-scored push-through blister backing and methods of making same.
Invention is credited to Carespodi, Dennis Lee.
Application Number | 20050284789 10/879382 |
Document ID | / |
Family ID | 35106827 |
Filed Date | 2005-12-29 |
United States Patent
Application |
20050284789 |
Kind Code |
A1 |
Carespodi, Dennis Lee |
December 29, 2005 |
Laser-scored push-through blister backing and methods of making
same
Abstract
Push-through blister backing laminates providing a laser-scored
outer layer and a metal substrate layer, and methods of making such
laminates are disclosed. The laser-scored blister backing may allow
for the use of a reduced amount of metal substrate as compared to
blister backing that is not laser scored. The laser-scored
push-through blister backing laminate may include a first,
laser-scored outer layer, and a push-through metal layer such that
the laminate functions as a push-through blister backing when it is
applied to a blister film.
Inventors: |
Carespodi, Dennis Lee;
(Winston-Salem, NC) |
Correspondence
Address: |
KILPATRICK STOCKTON LLP
1001 WEST FOURTH STREET
WINSTON-SALEM
NC
27101
|
Family ID: |
35106827 |
Appl. No.: |
10/879382 |
Filed: |
June 29, 2004 |
Current U.S.
Class: |
206/461 ;
428/35.8 |
Current CPC
Class: |
B32B 15/09 20130101;
B32B 2553/00 20130101; B32B 2310/0843 20130101; Y10T 428/1355
20150115; B65D 75/327 20130101; B32B 15/20 20130101; B32B 2309/105
20130101; B32B 15/08 20130101; B32B 7/12 20130101 |
Class at
Publication: |
206/461 ;
428/035.8 |
International
Class: |
B65D 073/00 |
Claims
That which is claimed is:
1. A blister backing laminate comprising a first outer layer and a
second metal substrate layer, wherein the outer layer is at least
partially scored with a laser such that the laminate functions as a
push-through blister backing.
2. The blister backing of claim 1, further comprising a layer of
adhesive bonding agent between the first outer layer and the metal
substrate layer and a layer of sealant for adhering the blister
backing to a blister film.
3. The blister backing of claim 2, wherein the outer layer is
scored through only part of the depth of the outer layer.
4. The blister backing of claim 2, wherein at least one score cuts
substantially through the entire depth of the outer layer.
5. The blister backing of claim 2, wherein at least one score cuts
substantially through the outer layer and at least part of the
adhesive bonding layer.
6. The blister backing of claim 2, wherein at least one score cuts
substantially through the entire depth of the outer layer and the
bonding layer down to the metal layer.
7. The blister backing of claim 1, wherein the outer layer
comprises a polymer film.
8. The blister backing of claim 1, wherein the outer layer
comprises polyethylene terephthalate (PET).
9. The blister backing of claim 1, wherein the outer layer
comprises a cellulosic substrate.
10. The blister backing of claim 1, wherein the metal layer
comprises aluminum foil.
11. The blister backing of claim 10, wherein the foil comprises a
thickness of about 0.0002 inches to about 0.002 inches.
12. The blister backing of claim 10, wherein the foil comprises a
thickness of about 0.00025 inches to about 0.001 inches.
13. The blister backing of claim 10, wherein the foil comprises a
thickness of about 0.0003 inches to about 0.0008 inches.
14. The blister backing of claim 1, wherein the laminate comprises
at least one layer of printing.
15. The blister backing of claim 1, wherein the laser comprises a
CO.sub.2 laser.
16. The blister backing of claim 1, wherein the laminate is adhered
to a blister film.
17. The blister backing of claim 16, wherein the portion of the
laminate that is laser scored is positioned over the opening of the
blister.
18. A push-through blister packaging comprising a blister backing
laminate applied to a blister film, the blister backing laminate
comprising a first outer layer and a second metal substrate layer,
wherein the outer layer is at least partially scored with a laser
such the laminate functions as a push-through blister backing.
19. A method for producing a push-through blister backing laminate
comprising forming a blister backing laminate comprising a first
outer layer and a second metal substrate layer, and using a laser
to at least partially score the outer layer of the laminate such
that the laminate functions as a push-through blister backing.
20. The method of claim 19, further comprising applying a layer of
adhesive bonding agent between the first outer layer and the metal
substrate layer and a layer of sealant to the surface of the metal
substrate layer that is opposite of the outer layer for adhering
the blister backing to a blister film.
21. The method of claim 20, wherein the outer layer is scored
through only part of the depth of the outer layer.
22. The method of claim 20, wherein at least one score cuts
substantially through the entire depth of the outer layer.
23. The method of claim 20, wherein at least one score cuts
substantially through the outer layer and at least part of the
adhesive bonding layer.
24. The method of claim 20, wherein at least one score cuts
substantially through the entire depth of the outer layer and the
bonding layer down to the metal layer.
25. The method of claim 19, wherein the outer layer comprises a
polymer film.
26. The method of claim 25, wherein the polymer film comprises
polyethylene terephthalate (PET).
27. The method of claim 19, wherein the outer layer comprises a
cellulosic substrate.
28. The method of claim 19, wherein the metal layer comprises
aluminum foil.
29. The method of claim 28, wherein the foil comprises a thickness
of about 0.0002 inches to about 0.002 inches.
30. The method of claim 28, wherein the foil comprises a thickness
of about 0.00025 inches to about 0.001 inches.
31. The method of claim 28, wherein the foil comprises a thickness
of about 0.0003 inches to about 0.0008 inches.
32. The method of claim 19, wherein the laminate comprises at least
one layer of printing.
33. The method of claim 19, wherein the laser comprises a CO.sub.2
laser.
34. The method of claim 19, wherein the blister backing laminate is
adhered to a blister film.
35. The method of claim 34, wherein the portion of the blister
backing laminate that is laser scored is positioned over the
opening of the blister.
36. The method of claim 34, wherein the blister backing laminate is
scored by a laser prior to adhering the backing to a blister
film.
37. The method of claim 34, wherein the blister backing laminate is
scored by a laser after adhering the backing to a blister film.
Description
FIELD OF INVENTION
[0001] The present invention relates to packaging. In particular,
the present invention relates to laser-scored push-through blister
backing and methods of making such backing.
BACKGROUND
[0002] Blister packages are commonly used to package ingestible
products, such as food and medicines, where it is convenient to
package the product as an individual portion. The individually
packaged item may be dispensed from the blister packing as needed,
leaving additional portions still packaged. Such blister packages
are also used for non-consumable products, such as toys, hardware
products, and almost any product imaginable.
[0003] Blister packages are generally characterized as having a
portion of the package being shaped as a bubble or "blister" that
functions to hold the product of interest. The blister package
typically comprises a sheet of translucent material such a
polyvinyl chloride (PVC), cyclic olefin copolymers (COC),
polystyrene, or similar materials that can be thermoformed into the
required shape. For example, blister packaging for a medicine in
the form of a pill might have a series of bubbles each shaped to
hold individual pills.
[0004] To complete the blister package, a backing layer comprising
a heat sealable web is sealed to the surface of the blister film to
cover the formed cavity and the product contained within. This heat
sealable web is commonly referred to as "blister backing."
[0005] There are many different configurations of blister backing
laminates but generally, they all fall into one of two categories:
"peelable" or "push-through." Peelable blister backing materials
are generally designed to be removed from the package by peeling
the backing from the blister to expose the product contained
within. Push-through blister backing is designed to fracture when
hand pressure is applied to the product cavity to push the product
through the backing material. Push-through blister backing may use
foil as the backing layer, since foil is able to protect the
product in the blister from the environment, but still can be
ruptured by pushing the product through the foil. Still, foil may
be expensive as compared to other materials used for typical
laminates, such as paper or plastic. Additionally, at a certain
thickness, foil can have sharp edges that may cause cuts or other
injury when the backing is being handled.
[0006] There is also a hybrid blister backing laminate available
that may combine the attributes of both peelable and push through
backing. This third type of blister backing may be referred to as
"peel-push," and involves peeling off one portion of a laminate
backing (such as a paper/plastic film layer) and pushing the
product through an underlying foil layer. One advantage of
"peel-push" blister backing is that it can allow for a reduction in
the foil layer thickness as compared to standard foil-based
push-through blister backing.
[0007] Both peelable and peel-push blister backing may have the
advantage of not requiring metal foil, or of requiring reduced
amounts of foil as compared to push-through blister backing. Still,
peeling the outer layer from a blister backing can be difficult, as
for example, when the container is small, or the individual using
the packaging has limited manual dexterity. Thus, for many
applications, push-through blister backing is preferred for its
convenience.
[0008] Although blister packaging provides numerous advantages and
savings with respect to the packaged product, blister packaging
individual items may require increased amounts of packaging
materials as compared to packaging items in bulk. Also, where the
packaging is used for ingestible items, the materials used for such
backing (e.g., paper, plastic and/or foil) must be of sufficiently
high quality to protect the product from the environment and if
necessary, maintain the product in sterile condition. Thus,
manufacturers are continually looking for ways to reduce the amount
of raw materials used for blister backing.
[0009] What is needed is blister backing that has the convenience
of push-through backing, but requiring less foil and other raw
materials. Also, what is needed is a method to provide easy access
push-through blister backing that provides a container having high
integrity, but that is convenient to open.
SUMMARY OF THE INVENTION
[0010] The present invention comprises laser-scored push-through
blister backing and methods of making such blister backing. In one
embodiment, the present invention comprises a push-through blister
backing laminate comprising a first outer layer and a second metal
substrate layer, wherein the outer layer is at least partially
scored with a laser such that the laminate functions as a
push-through blister backing when it is applied to a blister
film.
[0011] The present invention may also comprise methods of making a
push-through blister backing comprising reduced amounts of metal
substrate. In one embodiment, the present invention comprises
forming a blister backing laminate comprising a first outer layer
and a second metal substrate layer, and using a laser to at least
partially score the outer layer of the laminate such that the
laminate functions as a push-through blister backing when it is
applied to a blister film.
[0012] In yet another embodiment, the present invention comprises
an article of manufacture comprising a push-through blister
packaging. In one embodiment, the blister package comprises a
blister backing laminate applied to a blister film, the blister
backing laminate comprising a first outer layer and a second metal
substrate layer, wherein the outer layer is at least partially
scored with a laser such the laminate functions as a push-through
blister backing.
[0013] Various embodiments of the present invention may provide
certain advantages. In an embodiment, the push-through blister
backing of the present invention may require less metal foil than a
push-through blister backing that does not comprise a laser-scored
outer layer. The blister backing of the present invention may
maintain the high level of structural integrity typical of
peel-push foil-based blister backing while providing convenience of
the push-through format. For example, the push-through backing of
the present invention may be suitable for consumables such as food
items and medicines, as well for as non-consumable items such as
medical disposables, toys, hardware parts, and the like.
[0014] The present invention may be better understood by reference
to the description and figures that follow. It is to be understood
that the invention is not limited in its application to the
specific details as set forth in the following description,
figures, and claims, but is capable of other embodiments and of
being practiced or carried out in various ways.
BRIEF DESCRIPTION OF THE FIGURES
[0015] FIG. 1 shows a layer of blister backing that is not laser
scored in accordance with the prior art.
[0016] FIG. 2 shows a laser-scored blister backing that is at least
partly scored through a first outer layer and a second print layer
in accordance with an example embodiment of the present
invention.
[0017] FIG. 3 shows a laser-scored blister backing that is at least
partly scored through a first outer layer, a second printing layer,
and a third adhesive layer in accordance with an example embodiment
of the present invention.
[0018] FIG. 4 shows a bird's eye view of several types of
laser-scored patterns that may be used for blister backing in
accordance with example embodiments of the present invention.
[0019] FIG. 5 shows a means of providing continuous score lines on
a blister backing web in accordance with two example embodiments
(Panels 5A and 5B, respectively) of the present invention.
[0020] FIG. 6 shows an optical micrograph of a laser-scored blister
backing laminate in accordance with an example embodiment of the
present invention wherein a first outer layer of polyethylene
terephthalate (PET) film and a second layer of adhesive bonding
agent are scored down to the surface of a third layer of foil.
[0021] FIG. 7 shows an optical micrograph of a laser-scored blister
backing laminate in accordance with an example embodiment of the
present invention wherein a laminate comprising a first outer layer
of polyethylene terephthalate (PET) film, a second layer of low
density polyethylene (LDPE) adhesive bonding agent, and a third
layer of aluminum foil is scored down to, but not through, the
second, adhesive layer.
[0022] FIG. 8 shows a schematic representation of methods for
preparing laser-scored blister backing in accordance with various
example embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Embodiments of the present invention comprises
"push-through" blister backing laminates that use a laser-scored
outer layer and methods of making such backing. The present
invention may be embodied in a variety of ways. In one embodiment,
the present invention comprises a push-through blister backing
laminate comprising a first outer layer and a second metal
substrate layer, wherein the outer layer is at least partially
scored with a laser such that the laminate functions as a
push-through blister backing when it is applied to a blister
film.
[0024] In another embodiment, the present invention may comprise an
article of manufacture that includes a "push-through" blister
backing laminate. The blister backing laminate may comprise a
reduced amount of metal substrate as compared to laminates that are
not laser-scored. Thus, in one embodiment, the present invention
may comprise an article of manufacture comprising a push-through
blister packaging, wherein the packaging comprises a blister
backing laminate applied to a blister film, the blister backing
laminate comprising a first outer layer and a second metal
substrate layer, wherein the outer layer is at least partially
scored with a laser such the laminate functions as a push-through
blister backing.
[0025] The present invention may also comprise methods for
producing a push-through blister backing. The method may comprise
adding an outer layer that is at least partially scored with a
laser to a push-through backing. For example, in one embodiment,
the method comprises forming a blister backing laminate comprising
a first outer layer and a second metal substrate layer, and using a
laser to at least partially score the outer layer of the laminate
such that the laminate functions as a push-through blister backing
when it is applied to a blister film.
[0026] The laminate further may further include a layer of adhesive
bonding agent between the first outer layer and the metal substrate
layer. Also, a sealant may be used for adhering the blister backing
to a blister film. For example, a heat-sensitive sealant may be
applied to the surface of the metal layer that is opposite to the
outer layer for attaching the backing to a blister film.
[0027] The laminate may be scored to various depths to facilitate
the manufacture of blister backing having different strengths. In
one embodiment, the laminate may be scored such that the depth of
the outer layer is scored only in part. Alternatively and/or
additionally, the laminate may be scored such that at least one
score substantially cuts through the entire depth of the outer
layer. Or, the laminate may be scored such that at least one score
cuts substantially through the outer layer and at least part of a
second layer of adhesive bonding (and any intervening print layers)
that is positioned between the outer layer and the metal substrate
layer. In another embodiment, the laminate may be scored such that
at least one score cuts substantially through the entire depth of
the outer layer and any adhesive bonding layer that is positioned
between the outer layer and the metal substrate layer down to the
metal layer. In one embodiment, any print layers adjacent to the
upper surface of outer film may be at least partially scored. Also,
any print layers adjacent to the lower surface of outer film may be
at least partially scored. In an additional embodiment, any print
layers adjacent to the upper surface of the metal layer may be
substantially scored.
[0028] A variety of materials may be used for the outer layer of
the laminate. In an embodiment, the outer layer may comprise a
polymer film. In an embodiment, the exterior layer may comprise
polyethylene terephthalate (PET). Other materials for the outer
layer can be almost any polymer film used in the art of packaging
including, such as, but not limited to, polybutylene terephthalate
(PBT), copolymers of PET or of PBT (CoPET or CoPBT), vinylidene
chloride copolymers, polyethylene (PE), polypropylene (PP),
propylene ethylene copolymer (PPE), polyethylene napthalate (PEN),
nylon, or a nylon derivative such as nylon-MXD6.
[0029] In another embodiment, a metallized film, such as a
metallized oriented film, may be used as at least part of the outer
layer. In one embodiment, a metallized polyethylene terephthalate
(MPET) or metallized oriented polypropylene (MOPP) may be used.
Alternatively, films (e.g., PET) coated with silicon oxide and/or
aluminum oxide, such as those commercially available from Mitsui
Plastics (White Plains, N.Y.) or Toppan Printing Company (Japan),
respectively, may be used.
[0030] In another embodiment, a cellulosic material may be used as
the outer layer. For example, in an embodiment, paper may be used
as the outer layer. In yet another embodiment, the cellulosic
material may comprise a coarse paper product such as cardboard, or
cellulosic film.
[0031] The blister backing may comprise at least one layer of
printing as is known in the art of preparing multi-laminate layers.
The location of the printing may be varied depending upon the type
of packaging being produced. For example, there may be a layer of
printing on the inner surface of the metal substrate (e.g., between
the metal substrate layer and the sealant layer). Alternatively,
the backing may comprise a layer of printing on the inner surface
of the outer layer (e.g., between the outer layer and the adhesive
bonding layer). Or, the layer of printing may be on the upper
surface of the metal layer (e.g., between the metal substrate layer
and the adhesive bonding layer). In yet another embodiment, there
may be printing on the upper (outer) surface of the outer layer.
Finally, various combinations of printing layers as described above
may be used.
[0032] In one embodiment, the metal substrate layer may comprise
aluminum foil. Or, metals such as an iron or steel foil or a noble
metal foil may be used for some applications. The use of a
laser-scored exterior film may allow for a reduction in the
thickness of the metal layer. Thus, in various embodiments of the
present invention, the foil may comprise a thickness of about
0.0002 inches (5.08 .mu.m) to about 0.002 inches (50.8 .mu.m), or a
thickness of about 0.00025 inches (6.35 .mu.m) to about 0.001
inches (25.4 .mu.m), or a thickness of about 0.0003 inches (7.62
.mu.m) to about 0.0008 inches (20.3 .mu.m). Thus, in one
embodiment, laser-scoring of the outer film layer may comprise a
reduction in the amount of foil used in the blister backing of over
80%. Alternatively, laser-scoring of the outer film layer may
comprise a reduction in the amount of foil used in the blister
backing of over 50%. In yet another embodiment, laser-scoring of
the outer film layer may comprise a reduction in the amount of foil
used in the blister backing of over 20%.
[0033] In an embodiment, the laser used to score the film comprises
a CO.sub.2 laser. As is known in the art, the wavelength for a
CO.sub.2 laser may range from about 9 .mu.m to about 11 .mu.m, with
the most common wavelength being 10.6 .mu.m. The power used for the
laser may depend on the required size of the score as well as the
speed that the laser is moving relative to the substrate to be
scored. The power may range from a few watts to over 2,000 watts.
In one embodiment, the laser comprises a power in the range of
about 100 to about 800 watts. In another embodiment, the laser
comprises a power in the range of about 200 to about 400 watts.
[0034] As used herein, a score is a notch or line cut into at least
part of the surface the structure of interest, wherein the notch or
line may comprise a predetermined shape, size, or path. To form a
score, the laser beam may be focused on the outer layer of the
laminate to be scored, and the laminate and the laser beam moved
relative to one another. In one embodiment, the laser beam is moved
and the laminate to be scored is held stationary. Or, the laminate
may be moved, and the laser beam held stationary. Or, both the
laser beam and the laminate may be moved, as for example, where
non-linear score patterns, such as serpentine lines, are
created.
[0035] The size of the score line may depend on the focal width of
the laser beam as well as the speed that the blister backing is
moved. It is possible to create score lines that vary in both
length and/or width and in overall shape. In an embodiment, the
score may comprise a line or linear shape. Or, the score may have a
relatively equivalent length and width to comprise a substantially
square or circular shape.
[0036] The score line may be continuous or discontinuous in nature.
A continuous score line may be almost any length required. Examples
of continuous score lines may include a line that spans the length
or width of the blister surface. Also, a circle, or other shapes,
positioned over the blister opening may comprise a continuous
(uninterrupted) score. As used herein, a discontinuous score line
is a score line that includes non-scored regions between the scored
regions. In one embodiment, the score line is at least partly
discontinuous. The distance between scored regions in a
discontinuous score line may range from about 5 .mu.m to about
5,000 .mu.m. Alternatively, the distance between scored regions in
a score line may range from about 100 .mu.m to about 1,000 .mu.m,
or from about 20 .mu.m to about 500 .mu.m.
[0037] Depending upon the size (e.g., relative length and width) of
the score line, and the application for which the blister backing
is to be used, there may a predetermined number of holes used per
inch in a score. In one embodiment, there may be from about 2 to
500 holes per inch in the score. Alternatively from about 20 to 200
holes per inch may be present in a score.
[0038] Similarly, the width of the score line may be varied
depending upon the application for which the blister backing is to
be used. For example, a wider score line may be used for thicker
materials, or where easy opening of the blister backing is desired.
Conversely, narrow (or small) score lines may be used for some
applications. In alternate example embodiments, the score may have
a width that is in the range of from about 5 .mu.m to about 500
.mu.m, or from about 50 .mu.m to about 250 .mu.m, or from about 75
.mu.m to about 150 .mu.m.
[0039] It may be important to score the film in such a way as to
facilitate opening of individual blister units that are present as
part of a package having multiple blisters. Thus, it may be
important to score the blister backing so that the score lines are
positioned to allow an item positioned in the blister to be pushed
through a specific blister backing without causing items in other
blisters to be pushed out of their blisters. In one embodiment, the
portion of the backing that is laser-scored may be positioned over
the opening of the blister. Positioning of the score lines relative
to an underlying blister may be facilitated by scoring the blister
backing after it has been positioned with respect to the blister.
Thus, in an embodiment, the backing is adhered to a blister prior
to scoring.
[0040] Alternatively, it may be more efficient to make the backing
in sheets that may be laser scored at various predetermined
intervals and to then position the blister on the backing sheets.
Thus, in one embodiment, the backing is scored by a laser prior to
adhering the backing to a blister.
[0041] In yet another embodiment, continuous score lines may be
made along the length (or width) of the blister backing roll and
then the blister backing applied to a multi-blister pack so that
the lines are at least partly positioned over the blisters. In
using a blister backing comprising continuous score lines, there
may be sections of the score that are not positioned over the
blister opening, but that overlap other regions of the blister pack
(i.e., such as the walls and dividing sections between blister
openings). As the score lines that are not positioned over the
blister opening do not provide access to the blister, they should
not compromise the integrity of the package. By using
uni-directional continuous scoring, the score lines may be
positioned on the blister package in a one directional format.
[0042] The blister backing may be scored prior to modifications
such as pre-cutting of the film to fit on the blister backing.
Alternatively, the blister backing may be cut to the correct width
or length or otherwise sized prior to scoring.
[0043] Production of Blister Backing Laminates for
Laser-Scoring
[0044] Thus, embodiments of the present invention comprise a
"push-through" blister backing material that may provide improved
openability while maintaining a high level of structural integrity,
and methods of making such blister backing. Embodiments of the
push-through blister backing of the present invention may require
less aluminum foil than push-through blister backing that is not
laser-scored.
[0045] Conventional push-through blister backing may include two
basic layers: a foil-based substrate and a sealant. In some cases,
a paper/foil substrate comprising thin gauge foil laminate may be
used as a `push-through` backing. The foil substrate may provide a
barrier, as for example, to moisture and oxygen, to protect the
product. Also, the blister backing may be printed on either side of
the foil using conventional printing technologies. Sealant may be
applied to the foil to adhere the backing to the blister.
[0046] For a push-through blister backing, the foil may be selected
to have a thickness that will fracture easily under hand pressure
when the product is pushed through the backing. For push-through
backing, the foil layer may typically range from about 0.0008 inch
(0.8 mils; 20.3 .mu.m) to about 0.001 inch (1.0 mils; 25.4 .mu.m)
in thickness. The foil may be annealed foil (i.e., "soft" foil) or
unannealed foil (i.e., "hard" foil).
[0047] The sealant layer may function primarily to adhere the foil
substrate layer to the blister surface. The sealant layer may be
applied to the foil surface as a liquid coating. The sealant may
comprise a polymer or a polymer blend that will bond to the blister
film when exposed to adequate heat.
[0048] In contrast to the prior art, the present invention
comprises a push-through blister backing laminate comprising a
laser-scored outer layer. In one embodiment, the laminate may
comprise: (a) a first, outer layer; (b) a second layer of adhesive
bonding agent; (c) a third, metal layer; and (d) a fourth layer of
sealant for bonding the blister backing to a blister film. To allow
the blister backing to function as push-through backing, the first
outer layer may be at least partially scored with a laser. In an
embodiment, the outer layer may comprise a film and/or a cellulosic
substrate. In some cases, a metallized film may be used as the
outer layer.
[0049] The use of laser scoring is known in the art of packaging.
For example, U.S. Pat. No. 5,001,325, U.S. Pat. No. 6,207,925,
European Patent Application EP 0 357 841 A1, and Japanese Patent
Application 06184641 describe a method and/or apparatus for
providing score lines in packaging material by local evaporation
with a laser beam, where the laser beam and packaging material are
moved relative to one another. Also, U.S. Pat. No. 5,630,308
describes the use of at least two substantially parallel and linear
laser scores for tear control of packaging, and U.S. Pat. No.
4,549,063 describes the use of non-linear laser score lines that
enable a crack-and-peel feature to be introduced into laminate
backing. Also, U.S. Pat. Nos. 6,427,420 and 5,229,180 describe a
method for scoring the inner side of a laminate packaging film,
where the laser score provides a precut line to enable tearing the
package along that line. Laser scoring is also used for marking
packaging materials as described in U.S. Pat. No. 6,054,090, and
U.S. patent applications 2001/0036537A1 and 2002/0153639 A1.
[0050] Laser scoring has also been applied to blister packaging.
For example, U.S. Patent application 2003/0102247, and Japanese
patent applications 03352863 and 05314417, describe non-metal based
blister back packaging having laser-scored film. Also, U.S. Pat.
Nos. 6,212,858 and 5,820,953 describe the use of laser scoring to
allow for breakage of individual blister bubbles from a pack, and
U.S. Pat. No. 6,516,949 describes laser scoring of the blister
portion of a blister packaging as a means to create a tab that is
bonded to the backing. Still, these prior applications of laser
scoring do not use a laser scored exterior plastic film as a means
to reduce the amount of aluminum foil or other substrate layers
used for push-through blister backing.
[0051] A schematic representation of a cross-sectional view of a
conventional push-through blister backing laminate of the prior art
is shown as FIG. 1. It may be seen that a push-through blister
backing 2 may comprise an (optional) exterior print layer 4, a
layer of metal foil 6, an (optional) interior layer of print 4, and
a sealant layer 10. The sealant 10 may be used to adhere the
blister backing to the blister(s) 12 (i.e., blister film) which may
comprise a receptacle for the article (e.g., a single pill or the
like) of interest 14. FIG. 1 is not necessarily to scale, and in
many cases, the blister 12 will be substantially thicker than the
backing laminate 2. As used herein, a blister film comprises a
sheet or package being shaped as a bubble or "blister" that
functions to hold a product of interest. The blister film may
comprise a translucent material such a polyvinyl chloride (PVC),
cyclic olefin copolymers (COC), polystyrene, foil, or similar
materials that can be thermoformed or otherwise shaped into the
required format.
[0052] Embodiments of the present invention may comprise using a
laser-scored film as a layer for conventional push-through blister
backing. By using a laser-scored outer film, the amount of foil
used for the backing may be reduced. For example, in one
embodiment, the push-through blister backing of the present
invention may comprise the following structure: (a) an exterior
film and/or cellulosic material; (b) an adhesive bonding agent; (c)
an aluminum foil layer; and (d) a sealant layer to bond the blister
backing to the blister, where the outer film is scored to
facilitate opening of the package. In general, a push-through
structure of the present invention may comprise the four basic
layers described above. Additionally, optional layers of printing
may be included as is used in conventional foil blister
backing.
[0053] Schematic representations of example embodiments of the
push-through blister backing of the present invention are shown as
FIGS. 2 and 3. As shown in FIGS. 2 and 3, the blister backing of
the present invention 20 may comprise an outer print layer 4, an
exterior layer of film and/or cellulosic substrate 16; optionally
another layer of print 4; a layer of adhesive bonding agent 18; a
layer of metal foil 19; another optional layer of print 4, and
sealant 10.
[0054] A blister backing comprising the layers described above
would generally not function as a push-through blister material
because the tensile and burst strength of the exterior film layer
16 may prevent pushing the product 14 through the foil layer 19. In
order to overcome this limitation, so that the package may function
as a push-through blister, the exterior film layer may be cut
through, or scored 22, down to the bonding layer 18 (FIG. 2) or
down to the metal layer 19 (FIG. 3). In one embodiment, there may
be some variation to the depth of individual score lines (e.g.,
FIGS. 2 and 3). Scoring of the exterior film may be done by a
variety of methods known in the art. For example, as described
herein, the film may be scored using a CO.sub.2 laser.
[0055] In one embodiment, the blister pack may comprise individual
units, or "blisters" 12 that function to hold an item of interest
14 in its own unique package. The blisters of the package may be
formed by embossing a relatively thick sheet suitable for
containing the tablets or other item of interest. For example, the
blisters may be formed by embossing a sheet of a durable, generally
transparent plastic or other polymeric film that is about 0.004
inches to 0.02 inches (100 .mu.m to 500 .mu.m) thick. Blisters of
varying thickness may be used depending upon the application and
size of the blister, with thicker blisters generally preferred for
larger sized blisters or blisters requiring increased durability
(i.e., to be child resistant), and thinner blisters preferred for
smaller containers. For example, U.S. Pat. No. 5,785,180 describes
blister packaging comprising blisters 15 mm in thickness.
[0056] Typical materials used for blister film include a variety of
polymers and copolymers such as low density polyethylene or an
olefinic copolymers. As such, the selection, formulation, use and
specifications will be apparent to one skilled in the art of
designing and manufacturing blister packaging. Materials used may
include polyvinylchloride (PVC), fluoropolymers, cyclic polyolefin,
polyamides, polyethylene, polypropylene, polystyrene, polyacetal,
polybutylene terephthalate, polyethylene terephthalate, nylons, and
polyester. Blisters can also be produced from cold-formable foil
laminate such as polyamide/adhesive/foil- /adhesive/vinyl laminates
commercially available from Hueck Foil (Wall, N.J.) and Alcan
Packaging (Shelbyville, Ky.).
[0057] The blister 12 may a substantially transparent and flexible
polymeric material shaped and sized to contain a single item 14.
Or, the blister may be non-transparent, as for example, where a
foil laminate is used as the blister. Relative to the blister, the
covering sheet 20 may be a relatively thin sheet, such as a 10
.mu.m to 50 .mu.m thick laminated sheet.
[0058] Still referring to FIGS. 2 and 3, almost any type of plastic
and/or cellulosic material may be used according to the present
invention for the outer layer 16. As such, the selection,
formulation, use and specifications will be apparent to one skilled
in the art of designing and manufacturing laminates for use as
blister backing materials.
[0059] For example, in one embodiment, the outer layer 16 may
comprise a cellulosic substrate such as paper, cardboard, or the
like. In one embodiment, calendared bleach paper having a basis
weight of from about 20 to about 30 pounds per ream (StoraEnso;
Stevens Point, Wis.) may be used.
[0060] Alternatively and/or additionally, a plastic film layer may
be employed as the outer layer 16. Plastics that may be employed as
the outer layer of the blister backing may comprise a polyolefin,
polyester, polyamide, polycarbonate, polystyrene, or a substituted
polystyrene. Thus, suitable materials for the outer layer may
comprise polyethylene terephthalate (PET), polybutylene
terephthalate (PBT), copolymers of PET or of PBT (CoPET or CoPBT),
polyethylene (PE), polypropylene (PP), propylene ethylene copolymer
(PPE), nylon, such as nylon-MXD6 (Mitsubishi Gas Chemical Company,
Inc.), or polymethylpentene-TPX (Mitsui Chemicals America).
[0061] The films used for the blister backing outer layer may
comprise a monolayer or a multilayer film. Also, oriented polymeric
films (e.g., oriented PET films) may be preferred in some
embodiments. In certain embodiments, oriented films may provide
desired mechanical properties, such as temperature stability, lay
flat properties, chemical resistance, and printability, as compared
to unoriented films. The films may also be stretch-oriented, and in
some embodiments biaxially stretch-oriented, in order to improve
their mechanical properties. Alternatively, it may be advantageous
in some cases to provide a film with an unbalanced biaxial
orientation. For instance, it may be desirable to provide a greater
orientation to the polymeric film in the direction in which the
laser scoring is applied so as to reduce the possibility of cross
or uneven tears in the overwrap film.
[0062] Although oriented PET may be preferred, other oriented film
materials, such as oriented polypropylene (OPP), oriented polyamide
(OPA), and oriented polyethylene (OPE), or co-extruded films can be
used. Alternatively, the covering sheet 16 may comprise oriented
polyethylene-2,6 naphthalate film containing a polyethylene-2,6
naphthalate resin as a principal component. For example, PET films
suitable for use in the present invention are commercially
available from a number of sources, such as Mitsubisi Polyester
Film (Greer, S.C.), DuPont de Nemours & Company (Wilmington,
Del.), and SKC America (Covington, Ga.).
[0063] Where improved barrier properties are required, or a foil
like appearance is desired, it may also be possible to use a
metallized film, such as a metallized oriented film, as at least
part of the first outer layer 16. In an embodiment, the metallized
film may comprise metallized polyethylene terephthalate (MPET).
Vacuum metallization may be performed by a number of companies,
including Camvac Intl., Inc. (Morristown, Tenn.), and Vacumet
Corporation (Wayne, N.J.). The films may be metallized with a
shiny, highly reflective surface or with a satin-like,
low-reflectance surface depending on whether the polyester film
substrate has a glossy or a matte finish prior to metallizing. A
variety of metals may be used for metallization. In one embodiment,
the metal used may be aluminum. The metal may be applied at a
thickness as is required to increase the integrity or to highlight
the appearance of the outer film. For example, the metallization
may comprise a thickness that will provide an optical density of
about 1.5 to 3.0. After metallizing, the film may be wound onto
rolls in preparation for further processing and/or printing.
[0064] In certain embodiments, the outer layer may comprise a
mixture of films and/or paperboard. Various polymeric films may be
bonded to each other using extrusion or adhesive lamination
techniques. For example, paperboard may be bonded to polyolefin
with various adhesives such as low density polyethylene or any wet
bond adhesive typically used in the art. Similarly, polyesters may
be bonded to polyolefins, or biaxially oriented nylon may be bonded
to polyolefins such as BOPP by means of a polyurethane thermoset
adhesive such as Tycel.RTM. Polyurethane Adhesive from Liofol.RTM.
Company (Henkel Adhesives, Cary, N.C.).
[0065] Depending upon the material used, and the nature of the
packaging being made, the outer layer may comprise a variety of
thicknesses. In various embodiments, the thickness of the outer
layer may range from about 0.0002 inches to about 0.025 inches
(5.08 .mu.m to 635 .mu.m), or from about 0.0002 inches to about
0.005 inches (5.08 .mu.m to 127 em), or from about 0.0003 inches to
about 0.001 inches (7.62 .mu.m to 25.4 .mu.m). In one embodiment,
the film may comprise 48 gauge (0.00048 inch; 0.48 mils; 12.2
.mu.m) polyethylene terephthalate.
[0066] Referring again to FIGS. 2 and 3, the outer layer may
include a coloring agent or may be printed in some manner 4. Or, a
counterproof may be deposited for color as is known in the art. For
example, a paper layer may be printed using standard printing
techniques known in the art. Where the outer layer comprises a
polymer film, or a metallized film, the film may be printed on
either the metallized or non-metallized surface of the layer.
Depending upon the ink formulations used, it may be necessary to
prime coat the surface of the base layer with an adhesion promoting
material, such as polyethylene imine (PEI). In one embodiment,
transparent, metallic filled and/or opaque printing inks may be
applied by conventional printing techniques, such as rotogravure or
flexographic processes. For metallized films, transparent printing
ink that permits the reflectivity of the metallized surface to be
apparent through the printing ink may be used.
[0067] Again referring to FIGS. 2 and 3, an adhesive bonding agent
18 may be used to adhere the outer film layer 16 to the underlying
metal layer 19. Adhesives comprise compounds that can bond together
two materials by surface attachment. The selection of the specific
adhesive may depend upon factors such as the various components of
the blister backing that are to be bonded together, the equipment
used to carry out the application of the backing to the blister,
the desired sealing and opening properties, and other like factors.
For example, where the metal layer 19 is aluminum foil, and the
outer layer 16 consists primarily of a polyolefin such as high
density polyethylene, the adhesive layer 18 can be a urethane or
polyester adhesive. Typical adhesive materials may be either
thermoplastic or thermoset materials, depending upon the materials
to be bonded. Thermoplastic adhesives may comprise vinyl,
polyester, acrylic, and polyethylene polymers. Example adhesives
used may include the following: polyethylene (PE) homopolymers,
such as low density PE (LDPE), medium density PE (MDPE), linear low
density PE (LLDPE), and high density PE (HDPE); PE copolymers, such
as ethylene-acrylic acid copolymers (EAA) (commercially available
as PRIMACOR.RTM., Dow Chemical Company), ethylene methacrylic acid
copolymer (EMAA; commercially available as Nucrel.RTM. from Dupont
Packaging Products, Wilmington, Del.); polypropylene (PP); PP
copolymers; and maleic anhydride grafted polymers (commercially
available as ADMER.RTM. from Mitsui Chemicals America, Inc.,
Purchase N.Y.; or Bynel.RTM. from Dupont Packaging Products,
Wilmington, Del.). Also, ionomers such as Surlyn.RTM. (Dupont
Packing Products, Wilmington, Del.) may be used as adhesives.
[0068] Adhesives can be applied to the laminate using a variety of
techniques, such as wet or dry bond lamination, extrusion
lamination, or thermal lamination. In one embodiment, the adhesive
may be applied to a substrate in a fluid form, and then the
adhesive allowed to set to achieve a desirably high cohesive
strength. The transition from fluid to solid may be accomplished by
the heating of a thermoplastic, the release of a solvent or
carrier, a chemical reaction such as cross-linking, or other
suitable mechanism. Typically, wet or dry bond adhesives form
layers on the laminate backing that are at least about 0.00005 inch
(1.27 .mu.m) thick and usually have a thickness of less than about
0.0005 inch (12.7 .mu.m), and often less than about 0.0001 inch
(2.54 .mu.m). Extrusion adhesive layers are typically at least
0.00025 inches (6.35 .mu.m) thick and usually have a thickness of
less than 0.001 inches (25.4 .mu.m), or in other embodiments, less
than 0.0008 inches (20.3 .mu.m).
[0069] Again referring to FIGS. 2 and 3, the blister backing
laminate comprises a metal substrate 19 as one of the layers. The
metal substrate layer may also be printed using techniques such as
rotogravure or flexographic processes known in the art. In one
embodiment, the metal substrate may comprise aluminum foil. For
example, direct or continuous cast aluminum foil available in a
variety of thicknesses is commercially available from suppliers in
the art (Alcoa; Alcan; and RJR Packaging, Winston-Salem, N.C.). Or,
metals such as an iron or steel foil or a noble metal foil may be
used for some applications. The foil may comprise a thickness of
about 0.0002 inches to about 0.002 inches (5.08 .mu.m to 50.8
.mu.m). In yet another embodiment, the foil may comprise a
thickness of about 0.00025 inches (6.35 .mu.m) to about 0.001
inches (25.4 .mu.m). Or, in yet another embodiment, the foil may
comprise a thickness of about 0.0003 inches (7.6 .mu.m) to about
0.008 inches (20.32 .mu.m).
[0070] The laminated blister backing may comprise a layer of
sealant 10 to adhere the blister backing to the blister container.
In one embodiment, the sealant comprises a heat seal coating. A
heat seal coating may comprise a sealant selected to melt at a
temperature lower than the melting temperatures of other components
of the blister back package. Upon melting, the heat sealant
maintains adherence to the rest of the backing, but also adheres to
the surface material of the blister. As the heat sealant hardens,
it provides bonding, and hence a seal, between the blister and the
blister backing.
[0071] The selection of the specific sealant material may depend
upon the composition of the layer of the blister backing to which
the sealant material is laminated, the composition and properties
of the surface of the blister to which the sealant is expected to
bond, the equipment used to carry out the sealing process, the
desired sealing and opening properties, and other factors related
to the blister packaging being made. Thus, various sealant
materials used commercially for producing laminates may be employed
in the laser-scored laminates of the present invention. Such
coatings may be selected from materials such as vinyls, acrylics,
or polyolefins, which may be applied using common methods such as
spraying, dipping, curtain coating, roller coating, and the
like.
[0072] For example, in one embodiment, the heat seal coating may
comprise a water dispersion of a vinyl resin. The vinyl resin may
be ion-linked and acid-modified ethylene interpolymers known as
ionomer resins. Wax and other modifiers may be included to further
extend the range of performance properties. Thus, the heat-sealing
layer 10 may be made of a thermoplastic resin, such as a polyvinyl
acetate (PVA) resin, a polyvinyl butyral resin, a polyvinyl
chloride resin, a polyamide resin, a polyester resin, a polyolefin
resin, a polyacrylic resin, a cellulose ester resin, or a
polyethylene resin, a copolymer of some of those resins, or a
mixture of some of those resins. For example, thermoplastic
materials suitable for use as a heat seal layer may include
condensation polymers formed from ethylene gylcol and terephthalic
acid (PET); copolymers of ethylene and vinyl acetate; vinyl
coatings formed from a free radical additional reaction of vinyl
acetate and various vinyl monomers, acrylate esters, vinyl
chloride, vinylidene chloride, dibutyl and other dialkyl maleates
and other commercially available comonomers; polymers derived from
the polymerization of a carboxylic acid monomer and ethylene
reacted with sodium, potassium or zinc (ionomer); or a dispersion
of modified polypropylene in a high boiling aliphatic hydrocarbon.
In one example embodiment, polymers such as blend of ethylene vinyl
acetate and polybutylene that are formulated to produce peelable
seals may be used.
[0073] The heat seal layers may be clear. Alternatively, the
sealant may be translucent or opaque. In one embodiment,
thermoplastic materials having optimum hot tack characteristics and
minimum sealing temperatures in the range of about 150.degree. F.
to about 300.degree. F. are used. The application weight of the
heat seal polymers may range from about 2 to 6 pounds per 3,000
square feet of base layer.
[0074] Thus, depending upon the materials used for each layer, the
overall thickness of the blister backing laminate of the present
invention may range from 0.0005 inches to 0.02 inches (12.7 .mu.m
to 508 .mu.m). In other embodiments, the overall thickness of the
blister backing laminate may range from about 0.0005 inches to 0.01
inches (12.7 .mu.m to 254 .mu.m) or from 0.0007 inches to 0.004
inches (17.8 .mu.m to 101.6 .mu.m).
[0075] The laminate blister backing of the present invention (e.g.,
FIG. 2) can be produced by first providing a continuous
thermoplastic film (e.g., a PET film) of a desired thickness (e.g.,
from wound roll using a typical press unwind unit) as the upper,
exterior layer. Optionally, a 100% solids, solvent-based or
water-based overcoating may be applied to the outer PET surface. In
an embodiment, the film may be printed on either side or both sides
using standard rotogravure or flexographic techniques.
[0076] Next, a 100% solids, water-based, or solvent-based adhesive
formulation may be applied to the under side of the PET film
surface and/or the upper side of the aluminum foil. The foil may be
printed with ink and dried prior to application of the sealant. Or,
the foil may be printed on the upper side which is not coated with
sealant. The coated film may be passed through an oven to remove
the solvent if necessary, and the two layers (foil and film)
adhered together using laminating techniques standard in the art.
The sealant solution may then be applied to the surface of the foil
opposite of the film layer, and the entire laminate may then be
passed through an oven to remove the sealant solvent, cooled, and
rewound into a roll.
[0077] At this point, the resultant lamination may be unwound at
any time and slit to desired widths for application to the blister
material by heat sealing as is known in the art. The slit laminate
may further be subdivided into pieces of the desired size and
shape. As such, the laminated material may be provided by the
manufacturer as a so-called "one-component laminate" type of
process, and is capable of being used to provide blister backing of
the desired size and shape without the necessity of being subjected
to further lamination-type processing steps.
[0078] Once the laminate has been formed, the upper layer may be
scored using a laser. As is known in the art, a laser emits a
concentrated beam of light made up of light waves all of which are
substantially coherent (i.e., in phase and all having the same
wavelength) and thus, provides a highly focused beam. Lasers may be
named according to the particular material which is used to
generate the beam; generally, lasers will emit a characteristic
wavelength depending on the type of beam. Lasers suitable for
industrial use include gaseous lasers such as carbon dioxide or
helium-neon; solid-state light pumped lasers such as ruby,
neo-dymium-yttrium aluminum garnet (Nd-YAG), or glass;
semi-conductor lasers such as gallium arsenide; as well as plastic
lasers, and lasers using conjugated organic molecules such as
benzene, toluene or naphthalene. The laser used will depend on the
substrate targeted. In an embodiment, for scoring plastic or paper,
a CO.sub.2 laser is used. In other embodiments, a Nd:YAG laser may
be employed. The laser beam may be pulsed or continuous in nature.
For CO.sub.2 lasers, generally a continuous beam is used.
References describing laser scoring of packaging laminates include
U.S. Pat. Nos. 3,909,582; 3,626,143; 4,549,063; 5,001,325;
5,010,231; 5,630,308; 5,820,953; 6,054,090; and 6,207,925 providing
general descriptions of laser scoring, as well as U.S. Pat. No.
6,054,090, and U.S. Patent Application 2002/015639 (describing
marking packaging with CO.sub.2 or Nd:YAG lasers), and U.S. Patent
Application 2003/0102247 (describing the use of argon and YAG
lasers). The disclosure of each of these patents and patent
applications is incorporated by reference in their entireties
herein.
[0079] The wavelength of the laser beam can be any wavelength is
such that it will be selectively absorbed by the material used for
the film. The frequency of the radiation and other laser and beam
characteristics such as the output power of the laser and size of
the beam, can be any combination which will provide a beam of
radiant energy of sufficient intensity to effect scoring of the
film layer. For CO.sub.2 lasers, the wavelength generally ranges
from about to 9 .mu.m to about 11 .mu.m. In most embodiments, the
wavelength of the CO.sub.2 laser is about 10.6 .mu.m. For Nd:YAG
lasers, a wavelength of about 1.06 .mu.m is emitted. As is known in
the art, other lasers each have their own unique wavelengths.
[0080] Beam intensity may be determined by beam power and the
diameter of the score. If spot diameter is held constant, intensity
may be determined by the power of the laser beam. Thus, exposure
time may be based on the total amount of energy required to produce
the desired score line. In one embodiment, exposure time may be
determined by the relative rate of movement between the laser beam
and the blister backing.
[0081] Laser beams may be focused or unfocused. In one embodiment
of the present invention, the laser beams are focused. For example,
a CO.sub.2 laser beam may be focused to a spot about 100 .mu.m or
less. The diameter of the spot to which the laser beam is focused
can be of any suitable dimension depending on the thickness of the
layer to be scored and the type of score desired. Although beams of
short wavelengths can be focused to sizes less than 1 micron in
diameter, the spot size for a carbon dioxide laser having a
wavelength of 10.6 microns for the scored blister backing of the
present invention may range from about 20 .mu.m to 500 .mu.m, or in
other embodiments, from about 50 .mu.m to 400 .mu.m, or from about
80 .mu.m to 150 .mu.m, depending on beam mode structure and lens
focal length.
[0082] The output power of the laser can conceivably be of any
wattage. For example, CO.sub.2 lasers may comprise a power that
ranges from a few watts to megawatts. High wattages may be
preferred when it is desired that the laser emit a plurality of
beams. Multiple beams can be produced by any of the known means
such as beam splitting by partial reflectors. Generally, the beam
power used is varied depending on the thickness of the film layer
or laminate being irradiated and the relative motion between the
beam and the target blister backing. For an outer film layer of
about 0.0005 inches to about 0.004 inches (12.7 .mu.m to 101.6
.mu.m) in thickness, it may be advantageous to use beams of about
100 to 600 watts. In some embodiments, beams of about 200 to 600
watts, or from 200 to 400 watts may be employed.
[0083] For example, a carbon dioxide laser, commercially available
as a Lumonics Laser UPA 1500 (GSI Lumonics) may be used. Such
carbon dioxide flowing gas lasers have a power range of up to 2200
watts and can emit a continuous single-mode beam having a
wavelength of 10.6 microns, and a frequency of about 60 Hz. In one
embodiment, the beam may be focused to a spot diameter of about 100
.mu.m by an appropriately sized focal length lens.
[0084] In an example embodiment, the laser beam to be used for
producing scored laminates may be a continuous CO.sub.2 laser beam
of a wavelength of 10.6 .mu.m. The output capacity per unit area of
the laser may selectively be determined taking into consideration
the speed of processing the laminate. The sheet for forming the
laminate may be irradiated with the laser beam by fixing the laser
beam and moving the laminate to form straight scores.
Alternatively, the laminate may scanned with the laser beam to form
the cutting grooves in a desired pattern.
[0085] The laser-produced score may comprise one or more layers of
a laminate or film. A variety of shapes may be used as the scoring
pattern. In one embodiment, the scoring pattern may be centered on
the cavity containing the product. For example, a single line,
positioned along the length or the width of the blister sheet may
be used as the laser scoring pattern for an individual blister
unit. Alternatively, a plurality of lines intersecting in the
center to form a star-like design may be used. In another
embodiment, the scoring may comprise a circle or similar shape that
is large enough for the item of interest to be pushed through. Or,
the scoring may comprise a partial circle (or similar shape) such
that when the item is pushed from the blister through the backing,
the backing remains attached so as to be discarded with the empty
blister. FIG. 4 shows a bird's eye view looking directly down at
individual blisters 12 having the upper outer surface 16 scored 22
using various non-limiting shapes.
[0086] Referring now to FIG. 5, in one embodiment, scoring may
comprise forming continuous score lines 22 that extend the entire
length or width of a laminate roll 20. The laminate may then be
attached to a sheet of blisters 30 so that the score line(s) are
positioned at least partially over the individual blister openings
12. In this way, positioning of the laminate may only require
aligning of the laminate and blister sheet in one direction (i.e.,
along the y axis), since the score line is continuous along the
other direction (i.e., the x axis). The score line that is
positioned over the portion of the blister that does not comprise
an opening would not be expected to compromise the integrity of the
packaging, since the seal between the underlying foil and blister
substantially prevents access to the item 14 held in the blister.
In one embodiment, a single score may be used (e.g., FIG. 5A).
Alternatively, multiple score lines per blister opening may be used
(e.g., FIG. 5B)
[0087] Example photographs of scored laminate structures are shown
in FIGS. 6 and 7. As shown in FIG. 6, in one embodiment, the laser
score may substantially cut through an upper layer of PET film
(shown as the bottom layer in the orientation shown in FIG. 6) and
a second layer of adhesive to stop at a third layer of foil. Or, as
shown in FIG. 7, the laser score may substantially cut through an
upper layer of PET to stop at a second layer of low density
polyethylene (LDPE) adhesive, prior to reaching a third foil
layer.
[0088] FIG. 8 shows schematic representation of various embodiments
for the manufacture of laser-scored blister backing. As shown in
FIG. 8, scoring of the blister backing laminate may take place at
various points in the manufacture of the blister backing. In one
embodiment, the scoring of the laminate 110 may performed following
production of the laminate 100, but prior to sealing the laminate
on the blister 140 and prior to cutting (or slitting) the laminate
to size 120. Or, the laminate may be formed 100 and slit to size
120, scored 130, and then applied to the blisters 140. Or, the
laminate may be formed 100 and slit to size 120, applied to the
blister 140, and then the scoring performed 150.
EXAMPLE
[0089] Testing of laminated structures using a commercial carbon
dioxide micro-laser (Lumonics Laser UPA 1500, GSI Lumonics) was
performed. As described below, the results of the study indicate
that polyester film having an underlying layer of foil or low
density polyethylene (LDPE) may be scored to a predetermined depth
using a CO.sub.2 laser.
[0090] Two trial laminates were scored using a continuous CO.sub.2
laser beam. The composition of the two laminates used is provided
in Table 1. Thus, the first laminate (from outer layer to innermost
layers) was as follows: 0.00048 inch PET (polyester film grade
Melinex 813, Dupont Packaging); polyurethane adhesive (Adcote 518,
Rohm & Haas Company); 0.0015 inch foil (1235 CC aluminum foil,
RJR Packaging); adhesive; 0.00075 inch nylon (polyamide film N-201,
Enhance Packaging Technologies); adhesive (polyurethane adhesive,
grade 7975, Henkel Adhesives), and 0.00015 inch polyethylene
sealant (grade 151492, New England Extrusion). The second laminate
(from outer layer to innermost layers) was as follows: 0.00048 inch
PET (polyester film, grade SP65, SKC America); 0.0005 inch LDPE
(density 0.92; grade 50041, Dow Chemical Company); 0.000285 inch
foil (1235 CC aluminum foil, RJR Packaging); and 0.0001 inch
ionomer sealant (Surlyn.RTM. 1652SB, density=0.94, Dupont
Packaging).
1TABLE 1 Layer Laminate 1 Laminate 2 1 PET (0.48 mil) PET (0.48
mil) 2 Polyurethane Adhesive LDPE (0.5 mil) 3 Foil (1.5 mil) Foil
(0.285 mil) 4 Polyurethane Adhesive Ionomer Sealant (1.0 mil) 5
Polyamide Nylon (0.75 mil) 6 Polyurethane Adhesive 7 PE Sealant
(1.5 mil)
[0091] All trials were run using a 10 inch lens and a maximum
mirror speed. The experimental set-up and results are shown in
Table 2. Results for laminate 1 are also shown in FIG. 6, and
results for laminate 2 are also shown in FIG. 7.
2TABLE 2 Hole-hole Speed* Holes/in Holes/in Distance Length Width
Trial Material (fpm) Watts (expected) (actual) (.mu.m) (.mu.m)
(.mu.m) 1 1 800 400 * 60.95 416.73 118.24 104.39 2 1 600 400 75
80.22 316.65 133.98 103.39 3 1 400 400 100 117.82 215.59 130.28
104.39 4 1 300 400 120 156.89 161.90 129.33 98.86 1 2 300 400 120
153.37 165.62 113.84 89.15 2 2 300 300 120 157.98 160.78 130.73
79.92 3 2 300 200 120 155.71 163.12 110.18 72.09 4 2 350 200 110
135.22 187.84 103.59 71.63 5 2 350 300 110 136.09 186.64 104.95
79.45 6 2 350 400 110 136.11 186.61 124.77 102.16 7 2 400 200 100
118.66 214.05 81.29 60.22 8 2 400 300 100 119.02 213.41 120.14
82.68 9 2 400 400 100 118.49 214.36 113.16 90.54 10 2 500 400 85
95.79 265.17 130.27 105.79 11 2 600 400 75 80.57 315.24 119.18
97.18 *Speed for the laminate moving relative to the laser beam is
given in feet per minute (fpm).
[0092] It was found that at the settings employed, the CO.sub.2
laser could score substantially through the outer PET layer (FIG.
7) or the PET layer and the adhesive layer (FIG. 6), but did not
score the underlying foil layer on either structure. This was true
for all line speeds and power settings used. It was also found that
there may be a weak correlation between the power setting of the
laser and the width of the hole (r.sup.2=0.86). There was no
apparent correlation between the power settings and the length of
the hole (r.sup.2=0.48) or the spacing of the holes (r.sup.2=0.16).
As expected, there was a strong correlation between line speed and
hole spacing (r.sup.2=0.9997). There was no apparent correlation
between line speed and length (r.sup.2=0.03) or width
(r.sup.2=0.25) of the holes.
[0093] It will be understood that each of the elements described
above, or two or more together, may also find utility in
applications different from the types described. As used herein,
the singular forms "a", "an" and "the" include plural references
unless the context clearly dictates otherwise. The invention is not
intended to be limited to the details shown, since various
modifications and substitutions can be made without departing in
any way from the spirit of the present invention. As such, further
modifications and equivalents of the invention disclosed herein may
occur to persons skilled in the art using no more than routine
experimentation, and all such modifications and equivalents are
believed to be within the spirit and scope of the invention as
described herein.
* * * * *