U.S. patent application number 14/637764 was filed with the patent office on 2016-09-08 for multi-layer web and process for forming scored lidding film for blister packages.
The applicant listed for this patent is Tekni-Plex, Inc.. Invention is credited to Phil Bourgeois, Robin Van Landeghem.
Application Number | 20160257438 14/637764 |
Document ID | / |
Family ID | 55451558 |
Filed Date | 2016-09-08 |
United States Patent
Application |
20160257438 |
Kind Code |
A1 |
Van Landeghem; Robin ; et
al. |
September 8, 2016 |
MULTI-LAYER WEB AND PROCESS FOR FORMING SCORED LIDDING FILM FOR
BLISTER PACKAGES
Abstract
Multi-layer web and mechanical scoring process for forming
lidding film for push through blister packages. The web is
configured to resist the tensile forces encountered during
manufacturing processes, including slitting, rewinding and heat
sealing processes. A simplified web conversion process for creating
mechanically scored lidding film for blister packages is provided
at reduced investment and operational costs compared to prior art
systems.
Inventors: |
Van Landeghem; Robin;
(Sylvania, OH) ; Bourgeois; Phil; (Perrysburg,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tekni-Plex, Inc. |
King of Prussia |
PA |
US |
|
|
Family ID: |
55451558 |
Appl. No.: |
14/637764 |
Filed: |
March 4, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 3/30 20130101; B32B
7/05 20190101; B32B 27/08 20130101; B32B 27/306 20130101; B65B
11/52 20130101; B32B 27/308 20130101; B65D 75/327 20130101; B32B
2435/00 20130101; B32B 2307/31 20130101; B32B 2439/40 20130101;
B65D 75/36 20130101; B65B 47/00 20130101; B32B 2435/02 20130101;
B32B 27/36 20130101; B32B 2307/738 20130101; B32B 2250/24 20130101;
B32B 27/32 20130101; B32B 2307/732 20130101; B32B 3/04 20130101;
B32B 2270/00 20130101; B32B 2553/00 20130101; B32B 2307/702
20130101; B32B 2307/582 20130101; B32B 2307/704 20130101; B65D
2575/3227 20130101; B32B 2250/03 20130101 |
International
Class: |
B65B 11/52 20060101
B65B011/52; B65B 47/00 20060101 B65B047/00; B32B 27/32 20060101
B32B027/32; B32B 27/36 20060101 B32B027/36; B65D 75/36 20060101
B65D075/36; B32B 27/08 20060101 B32B027/08 |
Claims
1. A multi-layer web comprising: a multi-layer web of film windable
on a core and adapted to be scored and slit to form scored lidding
film for blister packages, the film being formed without a metal
layer and including an inner seal layer and an outer layer of
different thermoplastic polymer materials, the inner seal layer
configured to form a thermal weld seal with a base substrate of a
blister package, while the outer layer has a central scored area
configured to rupture and release a product contained in a recess
of a base substrate without breaking the weld seal, the web being
unwound from the core in a machine M direction transverse to a
central longitudinal axis CL of the core on which the web is wound,
the central scored area extending between opposing first and second
non-scored edge grip areas aligned in the M direction, the central
scored area being sized to cover a plurality of recesses in a base
substrate of a blister package without the need for registering the
scored area with individual recesses, the central scored area being
formed by passing the web against a scoring roller to mechanically
score fully or partially through the outer layer without scoring
the inner seal layer, the opposing first and second edge grip areas
being non-scored and each of a minimum width configured to provide
structural integrity to the web during winding and unwinding of the
web onto or from the core, and the non-scored edge grip areas being
slit to form a scored lidding film for blister packages, wherein
the central scored area comprises 75% to 99% of a total width of
the lidding film and the non-scored edge grip areas together
comprise 1% to 25% of the total width
2. A multi-layer web of claim 1, wherein the central scored area
comprises 80% to 99% of the total width.
3. A multi-layer web of claim 1, wherein the central scored area
comprises 85% to 99% of the total width.
4. A multi-layer web of claim 1, wherein the scoring depth is
between and 10% and 90% of the outer layer thickness.
5. A multi-layer web of claim 1, wherein the scoring depth is
between 20% and 80% of the outer layer thickness.
6. A multi-layer web of claim 1, wherein the scoring depth is
between 30% and 70% of the outer layer thickness.
7. A multi-layer web of claim 1, wherein the scoring comprises
spaced apart arrow shaped scored formations aligned in the M
direction.
8. A multi-layer web of claim 1, wherein the inner layer comprises
5% to 50% of the total film thickness and the outer layer comprises
50% to 95% of the total film thickness.
9. A multi-layer web of claim 1, wherein the inner layer comprises
5% to 40% of the total film thickness and the outer layer comprises
60% to 95% of the total film thickness.
10. A multi-layer web of claim 1, wherein the inner layer comprises
5% to 30% of the total film thickness and the outer layer comprises
70% to 95% of the total film thickness.
11. A multi-layer web of claim 1, wherein the lidding film is from
10 to 100 micron in thickness.
12. A multi-layer web of claim 1, wherein the lidding film is from
15 to 90 micron in thickness.
13. A multi-layer web of claim 1, wherein the lidding film is from
20 to 80 micron in thickness.
14. A multi-layer web of claim 1, wherein the scoring is uniformly
distributed in the central area.
15. A multi-layer web of claim 1, wherein the scoring width is from
5 to 100 microns.
16. A lidding film formed from the multi-layer web of claim 1,
combined with a thermoformed base substrate, the inner layer being
weld sealed to the base substrate.
17. A lidding film and base substrate of claim 16, cut to form a
single blister package.
18. A lidding film and base substrate of claim 16, made from
materials compatible in recycling.
19. A lidding film and base substrate of claim 18, both made from
polypropylene.
20. A lidding film and base substrate of claim 18, both made from
polyester.
21. A multi-layer web of claim 1, wherein the multi-layer web is
formed by co-extrusion of the inner seal layer and outer layer,
extrusion coating of the inner seal layer onto the outer layer, or
coating of the inner seal layer onto the outer layer via solvent,
water or solventless coating processes or by wet or dry bond
lamination of the inner seal layer to the outer layer.
22. A multi-layer web of claim 1, wherein the outer layer comprises
polyester or polyolefin.
23. A multi-layer web of claim 1, wherein the outer layer comprises
polyethylene terephthalate or polypropylene, including
homopolymers, copolymers and blends thereof.
24. A multi-layer web of claim 1, wherein the inner layer comprises
ethylene vinyl acetate, polyester, polyethylene, polypropylene, or
acrylic, including homopolymers, copolymers and blends thereof.
25. A multi-layer web of claim 1, wherein the outer layer comprises
semi-crystalline polyethylene terephthalate and the inner layer
comprises an amorphous polyethylene terephthalate copolymer.
26. A multi-layer web of claim 1, wherein the outer layer comprises
homopolymer polypropylene and the inner layer comprises
polypropylene copolymer.
27. A method of forming blister packages comprising steps of:
providing a master roll of the multi-layer web of claim 1, the
master roll configured to form scored lidding film for multiple
blister packages across a width W of the master roll transverse to
the M direction, unwinding a length of the master roll in the M
direction, passing the length of the master roll against a scoring
roller to mechanically score only the outer layer of the film,
wherein multiple central scored areas are formed across the width
of the master roll between non-scored areas, slitting the master
roll along the M direction in the non-scored edge grip areas
between two central scored areas to form multiple slit rolls of
scored lidding film, unwinding a slit roll of lidding film and
attaching a series of base substrates along a length of the unwound
slit roll to form a series of blister packages.
28. A method of claim 27, further comprising cutting individual
blister packages from the series of blister packages.
29. An apparatus for forming blister packages according to the
method of claim 27 including a plurality of stations for in-line
forming of a series of blister packages, the stations comprising: a
base forming station for unwinding a roll of base film from a core
in a machine direction M, followed by heating and thermoforming the
base film to form a series of thermoformed base substrates with
product recesses in the base film aligned along the M direction, a
filling station for dispensing product into the recesses of the
series of base substrates, a thermal sealing station, receiving the
filled series of base substrates and a slit roll of scored lidding
film, for sealing the inner layer of the scored lidding film to the
filled base substrates to form a series of sealed blister packages,
and a cutting station for cutting individual blister packages from
the series.
30. An apparatus for forming blister packages including a plurality
of stations for in-line forming of a series of blister packages,
the stations comprising: a base forming station for unwinding a
roll of base film from a core in a machine direction M, followed by
heating and thermoforming the base film to form a series of
thermoformed base substrates with product recesses in the base film
aligned along the M direction, a filling station for dispensing
product into the recesses of the series of base substrates, a roll
of scored lidding film on a core having a series of central scored
areas between nonscored areas aligned along a machine direction M,
a thermal sealing station, receiving the series of filled base
substrates and a length of the scored lidding film unwound from the
core in the M direction, wherein the inner layer of the scored
lidding film is sealed to each filled base substrate with the
central scored area over the recesses of the substrate to form a
series of sealed blister packages, and a cutting station for
cutting individual blister packages from the series.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to lidding film for a blister
package and more particularly to a multi-layer web and mechanical
scoring process for forming such lidding film.
BACKGROUND OF THE INVENTION
[0002] Blister packaging is known for receiving a product, e.g., in
tablet or powder form, wherein each of the individual recesses or
compartments of the base substrate can be provided with one product
or the like and the packaging can then be sealed with a cover,
e.g., in the form of a lidding film. The lidding film is sealed to
the base substrate on plane surfaces provided between the recesses
and along recesses outer edges of the base. As a result, the
packaged material is sealed tight against the exterior environment
and each individual product in the various compartments is mutually
separated from one another. Packaging of this type is known as
"push-through" blister packaging when the product in an individual
recess can be removed by manually pressing on the base substrate
(below the recess) and pushing the product through the lidding
film.
[0003] Blister packages are known having a base section made of
plastic and a cover that includes an aluminum foil or an aluminum
foil containing composite. When such packaging material is
recycled, waste products from the different materials are obtained,
some of which are still adhesively or weld bonded to one another.
This poses difficulty in recycling of such packaging materials.
[0004] One type of all-plastic blister package has a peelable (as
opposed to push through) heat seal lid. The opening action
(removing the peelable film) is generally considered less user
friendly (e.g., more difficult for seniors) compared to the
push-through lidding films. Also, the peelable heat seal
formulations are generally of different materials than the base,
which impacts recyclability.
[0005] Another type of lidding film for blister packages,
consisting of mineral filled thermoplastic polymer components, is
described in U.S. Pat. Nos. 5,932,338 and 6,006,913. One lidding
film of this type is commercially available from Etimex GMBH
(http://www.etimex-pp.com/), under the "Purelay" brand. These films
are devoid of metal foils, and possess frangible push-through
characteristics. However, these mineral based films are known to be
rigid or brittle, and difficult to process during slitting,
rewinding and heat sealing. While the push-through force for a
given package design can theoretically be tailored by altering the
mineral filler content, the range for such adjustments is limited.
At low mineral filler content an excessive push-through force is
generally required to allow the contents to break through the film.
At higher mineral filler content, the film may be too brittle to
handle during the slitting, rewinding and heat sealing processes
and may prematurely fracture during such handling and conversion
processes.
[0006] An all-polymer lidding film, devoid of metal foils typically
requires scoring of the film to enable the push-through
characteristic. Scoring can be performed either mechanically or by
laser scoring. Laser scoring is significantly more expensive and
typically costs multiple times per unit cost of a mechanical
scoring process.
[0007] Thus there is an ongoing need for materials and processes
for making push through blister packaging that overcome the
limitations of the prior art.
SUMMARY OF THE INVENTION
[0008] The present invention provides a multi-layer web and
mechanical scoring process for forming lidding film for push
through blister packages. The web is configured to resist the
tensile forces encountered during manufacturing processes,
including slitting, rewinding and heat sealing processes. A
simplified web conversion process for creating mechanically scored
lidding film for blister packages is provided at reduced investment
and operational costs compared to prior art systems. These and
other advantages of the invention are described below with respect
to various embodiments of the invention.
[0009] In one embodiment of the present invention a multi-layer web
is provided comprising: a multi-layer web of film windable on a
core and adapted to be scored and slit to form scored lidding film
for blister packages, the film being formed without a metal layer
and including an inner seal layer and an outer layer comprising
different thermoplastic polymer materials,
the inner seal layer configured to form a thermal weld seal with a
base substrate of a blister package, while the outer layer has a
central scored area configured to rupture and release a product
contained in a recess of a base substrate without breaking the weld
seal, the web being unwound from the core in a machine M direction
transverse to a central longitudinal axis CL of the core on which
the web is wound, the central scored area extending between
opposing first and second non-scored edge grip areas aligned in the
M direction, the central scored area being sized to cover a
plurality of recesses in a base substrate of a blister package
without the need for registering the scored area with individual
recesses, the central scored area being formed by passing the web
against a scoring roller to mechanically score fully or partially
through the outer layer without scoring the inner seal layer, the
opposing first and second edge grip areas being non-scored and each
of a minimum width configured to provide structural integrity to
the web during winding and unwinding of the web onto or from the
core, and the non-scored edge grip areas being slit to form a
scored lidding film for blister packages, wherein the central
scored area comprises 75% to 99% of a total width of the slit
lidding film and the non-scored edge grip areas together comprise
1% to 25% of the total width of the slit lidding film.
[0010] In another embodiment of the present invention, a
multi-layer web is provided, wherein the central scored area
comprises 80% to 99% of the total width of the slit lidding
film.
[0011] In another embodiment of the present invention a multi-layer
web is provided, wherein the central scored area comprises 85% to
99% of the total width of the slit lidding film.
[0012] In another embodiment of the present invention a multi-layer
web is provided, wherein the scoring depth is between and 10% and
90% of the outer layer thickness.
[0013] In another embodiment of the present invention a multi-layer
web is provided, wherein the scoring depth is between 20% and 80%
of the outer layer thickness.
[0014] In another embodiment of the present invention a multi-layer
web is provided, wherein the scoring depth is between 30% and 70%
of the outer layer thickness.
[0015] In another embodiment of the present invention a multi-layer
web is provided, wherein the scoring comprises spaced apart arrow
shaped scored formations aligned in the M direction.
[0016] In another embodiment of the present invention a multi-layer
web is provided, wherein the inner layer comprises 5% to 50% of the
total lidding film thickness and the outer layer comprises 50% to
95% of the total lidding film thickness.
[0017] In another embodiment of the present invention a multi-layer
web is provided, wherein the inner layer comprises 5% to 40% of the
total lidding film thickness and the outer layer comprises 60% to
95% of the total lidding film thickness.
[0018] In another embodiment of the present invention a multi-layer
web is provided, wherein the inner layer comprises 5% to 30% of the
total lidding film thickness and the outer layer comprises 70% to
95% of the total lidding film thickness.
[0019] In another embodiment of the present invention a multi-layer
web is provided, wherein the lidding film is from 10 to 100 micron
in thickness.
[0020] In another embodiment of the present invention a multi-layer
web is provided, wherein the lidding film is from 15 to 90 micron
in thickness.
[0021] In another embodiment of the present invention a multi-layer
web is provided, wherein the lidding film is from 20 to 80 micron
in thickness.
[0022] In another embodiment of the present invention a multi-layer
web is provided, wherein the scoring is uniformly distributed in
the central area.
[0023] In another embodiment of the present invention a multi-layer
web is provided, wherein the scoring width is from 5 to 100
microns.
[0024] In another embodiment of the present invention a lidding
film is formed from the multi-layer web, combined with a
thermoformed base substrate, the inner layer being weld sealed to
the base substrate.
[0025] In another embodiment of the present invention a lidding
film and base substrate is cut to form a single blister
package.
[0026] In another embodiment of the present invention a lidding
film and base substrate is made from materials compatible in
recycling.
[0027] In another embodiment of the present invention a multi-layer
web is provided, wherein the multi-layer web is formed by
co-extrusion of the inner seal layer and outer layer, extrusion
coating of the inner seal layer onto the outer layer, or coating of
the inner seal layer onto the outer layer via solvent, water or
solventless coating processes or by wet or dry bond lamination of
the inner seal layer to the outer layer.
[0028] In another embodiment of the present invention a multi-layer
web is provided, wherein the outer layer comprises polyester or
polyolefin.
[0029] In another embodiment of the present invention a multi-layer
web is provided, wherein the outer layer comprises polyethylene
terephthalate or polypropylene, including homopolymers, copolymers
and blends thereof.
[0030] In another embodiment of the present invention a multi-layer
web is provided, wherein the inner layer comprises ethylene vinyl
acetate copolymers, polyester, polyethylene, polypropylene, or
acrylic, including homopolymers, copolymers and blends thereof.
[0031] In another embodiment of the present invention a multi-layer
web is provided, wherein the outer layer comprises a semi
crystalline polyethylene terephthalate polymer or copolymer and the
inner layer comprises an amorphous polyethylene terephthalate
copolymer.
[0032] In another embodiment of the present invention, a method of
forming blister packages is provided comprising steps of:
providing a master roll of the multi-layer web wound on a core, the
master roll configured to form scored lidding film for multiple
blister packages across a width W of the master roll transverse to
the machine M direction, unwinding a length of the master roll from
the core in the M direction, passing the length of the master roll
against a rotating scoring roller to mechanically score only the
outer layer of the film, wherein multiple central scored areas are
formed across the width of the master roll between non-scored
areas, slitting the master roll along the M direction in the
non-scored areas between central scored areas to form multiple slit
rolls of scored lidding film, each slit roll being wound onto a
core unwinding a slit roll of lidding film from the core and
attaching a series of base substrates along a length of the unwound
slit roll to form a series of blister packages.
[0033] In another embodiment of the present invention, the method
of forming blister packages, further comprises cutting individual
blister packages from the series of blister packages.
[0034] In another embodiment of the present invention an apparatus
for forming blister packages is provided including a plurality of
stations for in-line forming of a series of blister packages, the
stations comprising:
a base forming station for unwinding a roll of base film from a
core in a machine direction M, followed by heating and
thermoforming the base film to form a series of thermoformed base
substrates with product recesses in the base film aligned along the
M direction, a filling station for dispensing product into the
recesses of the series of base substrates, a roll of scored lidding
film on a core having a series of central scored areas between
nonscored areas aligned along a machine direction M, a thermal
sealing station, receiving the series of filled base substrates and
a length of the scored lidding film unwound from the core in the M
direction wherein the inner layer of the scored lidding film is
sealed to each filled base substrate with the central scored area
over the recesses of the substrate to form a series of sealed
blister packages, and a cutting station for cutting individual
blister packages from the series.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The following figures illustrate various embodiments of the
invention in more detail.
[0036] FIG. 1 is a schematic view of a blister package assembly
apparatus and process according to one embodiment of the
invention;
[0037] FIG. 2A is an exploded perspective view of a base substrate
and scored lidding film for forming a push through blister package
according to one embodiment;
[0038] FIG. 2B is a cross sectional view of an assembled blister
package from the components of FIG. 2A, showing an individual
product in each recess of the base substrate and the scored lidding
film attached to the base substrate;
[0039] FIG. 3 is a schematic view of a scoring, slitting, and
rewinding conversion process according to one embodiment;
[0040] FIG. 4 is a top plan view of a master web of the lidding
film prior to and after scoring and slitting to create multiple
slit rows of scored lidding film according to one embodiment;
[0041] FIG. 5A is top plan view of a section of one slit roll of
scored lidding film having a central scored area with an array of
scored arrow-shaped formations, extending between opposing first
and second edge grip areas that are not scored, and FIG. 5B is a
cross sectional view of the scored lidding film of FIG. 5A;
[0042] FIG. 6A is a perspective view of an assembled blister
package of the type shown in FIGS. 2A-2B, prior to cutting
(removing) the unscored edge areas of the lidding film and
substrate below, and
[0043] FIG. 6B is the final package (with the unscored edge areas
removed)
[0044] FIG. 7A is a perspective view of a first pair of scoring
rollers for forming a scored lidding film according to one
embodiment, and FIG. 7B is a perspective view of a second pair of
scoring rollers for forming three scored central areas (for three
blister packages) across the width of the scoring rollers.
DETAILED DESCRIPTION OF THE INVENTION
[0045] FIG. 1 illustrates one embodiment of a process for making a
push through blister package, of the type illustrated in FIGS. 2
and 5-6, according to one embodiment of the invention.
[0046] In FIG. 1 there is schematically shown an inline forming and
assembly apparatus for making a series of blister packages, A final
blister package 10 is shown exiting the final cutting station 7.
The packages are formed by unwinding a base film (web 12W) from a
roll 48 on a core, forming and then filing recesses in the base
film at stations 2-5 and then attaching a lidding film (web 14W),
unwound from roll 40 on a core, to the formed and filled base
substrate film at station 6, followed by cutting the final package
at station 7. The final cut package, comprising a base substrate 12
and a scored lidding film 14 is shown in FIGS. 2A-2B and FIG. 6B.
FIG. 6A shows the attached lidding film and base substrate prior to
cutting.
[0047] More specifically, beginning at the bottom left hand side of
FIG. 1, a web 12W of base film is unwound from roll 48 on a core
and heated at pre-heat station 2; the base film is then
thermoformed at forming station 3 to form recesses or hollows 16 in
a series of base substrates (along machine direction M). The formed
series of base substrates is then fed around rollers 9 to a filling
station 5 where each recess 16 is filled with product 20. The
filled base film 12W is then aligned with the web 14W of lidding
film, being unwound from roll 40 on a core, wherein the open end of
each filled recess 16 is brought into alignment with the lidding
film web 12W at a thermal sealing station 6 (or similar station)
for securing the lidding film to the base substrate. The lidding
film is sealed to top planar areas 15 in between and around the
recesses of the base to close each recess 16 and seal the product
20 therein (see FIG. 2). The combined lidding film and base
substrate is then cut and separated as desired at cutting station 7
to define individual blister packages 10 each having a desired
number of products in the thermoformed recesses (e.g., as shown in
FIGS. 2A-2B and 6B). Thus at station 7 there are edge trim areas of
both the lidding film and underlying base substrate removed to form
the final cut blister package 10.
[0048] The schematic of FIG. 1 is provided to show the steps of an
assembly process for a finished package according to one
embodiment. The steps may be performed together or as part of
separate operations. For example, the lidding film 14 may be
printed, coated or die cut as part of one operation or separate
operations. As described further in regard to FIGS. 3-4 and 7, each
roll of lidding film 40 may be slit from a master web roll 30 that
has been scored, and then slit into individual slit lidding film
rolls (such as roll 40 in FIG. 1). Other operations may be
performed within the conversion process as known to the skilled
person.
[0049] FIG. 2A illustrates, in exploded view, the components of a
blister package 10 according to one embodiment. The package 10
includes a base substrate 12 and a scored lidding film 14. The base
12 includes a plurality of recesses 16 that are arranged in an
aligned pattern or array (e.g., rectangular array of rows and
columns), with each recess 16 separated by a top planar sealing
flange 15. Each recess 16 retains product 20. The blister package
may be formed with any number of recesses, and each recess may hold
an individual product or multiple products or a quantity of loose
product, such as a powder or granular material. A series of
separation lines (not shown) may be provided within the sealing
flange 15, between adjacent recesses, or group of multiple
recesses, as desired, to permit separation of a portion of the base
substrate from the remainder.
[0050] The lidding film 14 is joined to the base substrate 12 of a
package as shown in the cross sectional view of FIG. 2B. The
lidding film 14 is joined to the sealing flange 15 by a thermal
weld seal, such that each individual recess 16 containing product
20 is covered and closed. A score pattern 22 of scored formations
23 (FIGS. 2A-2B) is formed only in an outer layer 18 of the
multi-layer lidding film 14. The score pattern 22 is provided for
the initiation and propagation of the tear within the lidding film
14 overlying the recess 16, upon application of a force against the
base material forming the recess 16, and the product 20 retained
therein. In FIG. 2B, the force is represented by the arrow F, with
the resulting tear in the lidding film 14 occurring in an area of
the scored lidding film 14 over the recess 16, for releasing the
previously sealed product 20. As such, the lidding film is designed
to tear above a recess, without breaking the weld seal between the
lidding film and base substrate.
[0051] As shown in FIGS. 2, 5 and 6, the score pattern 22 in the
disclosed embodiment includes a plurality of individual scored
formations 23, separated by non-scored areas 25 surrounding each
scored formation. Each scored formation in this example is shaped
like an arrow head, including two generally straight lines 23A and
23B, joined at an apex 23C (FIG. 5A). The apexes of the scored
formations 23 all point in the machine direction M in this example
(same as the lengthwise package direction L). The individual scored
formations may be aligned in rows and columns, which are
equidistantly spaced from one another, where each row is offset
with respect to the adjacent rows. Other patterns (e.g., irregular
spacing between scored formations) may be used. The shape of the
scored formation 23 and the size, depth, width of scoring lines
23A, 23B and number of scored formations across the width of the
blister package, and/or across the width of each recess, can be
varied for purposes of customizing the package based on the
materials used for the base film and lidding film, the contents
(product enclosed), and the desired push-through force.
[0052] As described in greater detail below, the scored formations
23 extend across all of the recesses 16 of the lidding film in the
final package 10 such that no registration (alignment) of the
scored formations of the lidding film and the recesses is required.
This greatly simplifies production and assembly.
[0053] As shown in cross section in FIGS. 2B and 5B, the lidding
film 14 is a multi-layer film comprising inner and outer film
layers of different thermoplastic polymer materials, and without a
metal layer. An inner seal layer 17 of the lidding film 14 forms a
weld seal bond to the top surface (the sealing flange 15) of the
base substrate 12. The inner seal layer 17 is formed of a
thermoplastic polymer material that softens at a lower melt
temperature than the outer layer 18, in order to bond the inner
layer to the base substrate. The inner layer material for forming
the weld (non-peelable) seal may comprise any of various known
sealing materials based on, for example, ethylene vinyl acetate
(EVA), polyester, polyolefin, acrylic, and others, including
co-polymers, homopolymers and blends thereof. The outer layer 18 of
the lidding film is a heat resistant layer, compared to the inner
layer. The outer layer resists softening and maintains structural
integrity for handling of the lidding film composite when the inner
layer is softened for weld sealing to the base substrate. The outer
layer may comprise any of various thermoplastic polymer materials,
such as polyester, (e.g., polyethylene terephthalate PET),
polyolefin (e.g., polypropylene or polyethylene), including
homopolymers, co-polymers, and blends thereof. As used herein, the
different thermoplastic polymer materials of the inner and outer
film layers 17, 18 includes polymers of different chemistry or
polymers of the same chemistry (thermoplastic family, such as
polyester) but having different characteristics (e.g., crystalline,
semi-crystalline, or amorphous) and/or comprising homopolymers,
copolymers of blends thereof. In one example the outer layer
comprises homopolymer polypropylene and the inner layer comprises
polypropylene copolymer. In another example the outer layer
comprises semi-crystalline polyethylene terephthatlate (PET) and
the inner layer comprises an amorphous polyethylene terephthalate
copolymer.
[0054] Also, the lidding film materials and base substrate
materials are preferably compatible in commercial recycling
streams. For example, both the base substrate and lidding film
materials may be from the same thermoplastic family (e.g.,
polypropylene, or polyester). Materials that are compatible in
recycling means materials of the same thermoplastic family that are
melt compatible.
[0055] FIG. 3 illustrates a schematic view of one apparatus and
process for scoring and slitting a master web 30 of lidding film
being unwound from a master roll unwound unit 50 in order to
generate multiple individual scored and slit rolls of lidding film.
FIG. 4 illustrates a length of the master web 30 during the scoring
and slitting process illustrated in FIG. 3. The master web of
lidding film 30 has an initial width W1 in a direction transverse T
to the machine direction M (the machine direction being the
direction in which the web 30 is advanced through the scoring and
slitting apparatus). In this example, the master web 30 (shown
moving to the left in FIGS. 3-4) will be first scored by scoring
unit 52 (FIG. 3.). The scored web is then slit by slitting station
54 (FIG. 3). The result is six individual scored and slit rolls
14A-F of lidding film. Each scored and slit roll is then rewound
onto a separate core at rewind station 56 (only two of six cores
are shown in cross section).
[0056] The film from the master web 30 after passing through the
scoring and slitting stations 52, 54 includes non-scored outermost
opposing edge trim areas 31, 32 (FIG. 4) along the length of the
roll (in the M direction), and between those non-scored edges
31,32, six (6) equally sized individual lidding films 14A, 14B,
14C, 14D, 14E, 14F. Each individual lidding film 14A-F of width W2
has a central scored area 40 of width B for forming the scored
lidding film of a blister package, and opposing non-scored edge
grip areas 41, 42, each of width A. The edge grip areas 41, 42
extend along the longitudinal length L (same as machine direction
M) of the film from the master web 30 that has been scored and
split into individual rolls 14.
[0057] FIG. 5A is a top view of a length of one slit roll of
lidding film (e.g. 14C), of width A+B+A, including central scored
area 40 of width B, and two opposing non-scored edge grip areas 41,
42 each of width A. FIG. 5B shows a cross section of the slit roll,
including outer layer 18 of thickness t1 and inner seal layer 17 of
thickness t2. The total film thickness t3 is the sum of t1+t2. The
scoring depth (SD) of the scored formations is also shown,
extending only partially through the thickness t1 of the outer
layer 18. The inner seal layer 17 is not scored.
[0058] As shown in FIG. 3, the master web 30 of lidding film is
unrolled from a master roll unwind unit 50, and fed to a scoring
station 52, where the web 30 is fed between two opposing rollers
53, 55, one roller 53 having formed thereon scoring surfaces 57
(see FIGS. 7A and 7B) for scoring the outer layer 18 of the web
film 30 to form the scored central area 40 of width B, between two
non-scored areas 41, 42 each of width A. After scoring, the scored
web 30A advances in line to a slitting station 54 where the scored
web 30A is slit into multiple slit rolls 30B, in this example into
six individual slit rolls 14A-F, each slit roll 14 then being wound
on a separate core as a separate roll 58, 59 at rewind station 56.
The outermost non-scored trim edges 31, 32 of the master roll 30
are removed during the slitting process (at station 54), such that
each of the six individual film rolls has the same width W2,
including the central scored area 40 of width B and two opposing
non-scored edges 41, 42 each of width A. The non-scored edges 41,
42 of each individual slit roll 30B provide structural integrity to
prevent tearing of the rolls during the scoring, slitting, and
winding/rewinding steps.
[0059] The scored formations 23 are preferably formed on a
continuous basis by a rotary die cut roller, such as scoring roller
53 shown in FIG. 7A. The scoring roller may have only a single
width B of scoring to form lidding film for a single blister
package 10, of width A+B+A. Alternatively as shown in FIG. 7B, the
scoring roller may include multiple scoring areas, each of width B,
for simultaneously forming multiple scored lidding films that are
later slit to form multiple slit rolls of scored lidding film.
[0060] In the example of FIG. 3 showing a scoring station 52, the
film is passed through the nip of a pair of opposing rollers 53,
55, one of which is a scoring roller 53. The opposing non-scoring
roller 55 supports the web film as it passes against the scoring
roller 53. Thus, as used herein passing against a scoring roller
includes the use of one or multiple rollers.
[0061] After rewinding, each individual scored lidding film roll
58, 59, can be unwound from its core and aligned with a formed base
substrate (filled with product) as shown in FIG. 1, for weld
sealing the lidding film to the substrate to form the filled
blister packages. In the present embodiment, the individual slit
rolls form narrow rolls 14A-14F, each having a width adapted for a
blister package. The slit rolls are then separately sealed to a
series of base substrates during the inline forming and sealing
operations, with the individual (or multiple) packages 10 then
being cut from the series of sealed base substrates and lidding
film formed inline in the machine direction. The non-scored edge
areas 41, 42 of the lidding film and underlying base substrate are
removed during the final die cutting of the individual blister
packages as shown in the final step (cutting station 7) of FIG.
1.
[0062] In alternative embodiments, a scored and slit roll of
lidding film may be wide enough to form multiple packages across
the width of the lidding film. The drawings and specification have
set forth a number of embodiments of the invention, which are
intended to be descriptive only and not for the purpose of
limitation. Variations will be apparent to those skilled in the art
and are intended to be included in the scope of the present
invention.
* * * * *
References