Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
DISCONTINUOUSLY LAMINATED FILM STRUCTURES
WITH IMPROVED VISUAL CHARACTERISTICS
[0001] Inventors: Michael G. Borchart, Theodore J. Fish, Kenneth E.
Cisek, and
Robert T. Dorsey.
BACKGROUND
[0002] As the costs of resin materials increase along with desires to
minimize the
impact of resin material waste, manufacturers are moving toward use of thinner
and
thinner gauges of resin films in their products. This is particularly true of
manufacturers
that implement high volumes of resin films in various forms, such as resin
films for use in
storage and waste products. While thinner gauge materials can represent
obvious cost
savings to the manufacturer, conventional production mechanisms can mean that
use of
thinner gauge film precursors results in lower durability of the end product.
Although
some recent technology may result, in some cases at least, in relatively
thinner gauge
products that may be as strong as their thicker counterparts, customers
naturally sense
from prior experience that thinner gauge materials are lower in quality and
durability.
[0003] One instant cue to a customer of lower quality and durability of
a bag is
not only how thick or thin the bag feels, but also how thin or weak the bag
"looks."
Generally speaking, customers tend to view translucence as an indication of
relatively
low strength. Thus, despite the fact that some conventional mechanisms can
improve
some aspects of film strength while nevertheless using thinner gauge film
materials, the
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translucence of such bags tends to cause customers to believe the bag is
nevertheless low
quality. Manufacturers may try to overcome these sorts of difficulties by
adding
colorants or voiding agents to minimize this issue.
100041 Depending on how they are used, however, colorants and voiding
agents
can sometimes weaken the chemical bonds in the film, and create a still weaker
film.
Moreover, the use of certain colors in a film or film structure may present
unique
challenges. For example, films with a white color may employ a pigment such as
titanium dioxide (TiO2). However, titanium dioxide is quite expensive and may
significantly increase the cost of a film that employs such a pigment. Other
conventional
mechanisms involve using multiple, very low gauge films in a laminate
structure, where
at least one of the films is colored. However, the aforementioned types of
color additions
to film, and the types of film structures are not typically well-suited for
some applications
and/or have proven to be problematic for various reasons in addition to those
noted
above.
[0005] For example, one color changeable laminate structure (or
"laminate")
includes a pair of films in intimate contact with each other, and further
includes a color
generating film positioned adjacent one of the films. So long as the films arc
in intimate
contact with each other, the laminate generates an interference color.
However, absent
intimate contact between the films, no color is generated. Thus, the color
changeable
laminate may not be well-suited for use in environments where, for example,
delamination of the films is possible. As well, production processes for this
structure can
be difficult, and in some cases must be strictly controlled to ensure intimate
contact
throughout the entirety of the laminated films.
[0006] Another laminate displays a color change when the laminate is
bent. This
is achieved with a color generating metal disposed on a film of the laminate.
The metal is
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in intimate contact with an anodic film, and creates color by light
interference absorption
effects. Absent intimate contact between the metal and the anodic film
however, the
color generation effects are not achieved. Moreover, production processes can
be
difficult, and in some cases must be strictly controlled to ensure intimate
contact between
all portions of the metal and the anodic film. As well, this laminate may not
be well-
suited for environments where: the use of metal is undesirable or impractical;
delamination of the metal and anodic film is possible; and/or, it is desired
to maintain the
color of the laminate notwithstanding temporary or permanent changes to the
geometry of
the laminate.
10007] As a final example, a further laminate structure can be
constructed to
display an irreversible color change upon delamination of two films in
intimate contact
with each other. Absent intimate initial contact between the films however,
the color
generation effects are not achieved. Thus, production processes must be
strictly
controlled to ensure intimate contact between the films so that when the films
are
dclaminated, the desired effect is achieved. As well, this laminate may not be
well-suited
for environments where it is desired to maintain the color of the laminate
notwithstanding
temporary or permanent changes to the geometry of the laminate. Finally, this
laminate
structure may necessitate user intervention to effect the delamination
necessary for
achievement of the irreversible color change.
100081 As the foregoing discussion suggests, there is a need for quality
end
products that, notwithstanding other aspects of their appearance and/or
tactile impression,
are configured to provide a positive indication to the consumer as to the
quality of those
products.
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BRIEF SUMMARY OF AN EXAMPLE EMBODIMENT
[0009] One or more embodiments within the scope of the invention may be
effective in overcoming one or more disadvantages in the art. One example
embodiment
is directed to a discontinuously laminated film that includes a first film
portion that is
ribbed, a second film portion that is un-ribbed; and a region of discontinuous
lamination
between the first film portion and the second film portion. The region of
discontinuous
lamination includes a plurality of regions where the first and second film
portions are
bonded together, and the region of discontinuous lamination also includes a
plurality of
regions where the first and second film portions are not bonded together.
Improved
strength in the end product is manifest, and is conveyed visually to the end
user.
100101 The foregoing embodiment is provided solely by way of example
and is
not intended to limit the scope of the invention in any way. Consistently,
various other
embodiments of a discontinuously laminated film, films, and associated
production
processes, within the scope of the invention are disclosed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The appended drawings contain figures of example embodiments to
further illustrate and clarify various aspects of the present invention. It
will be
appreciated that these drawings depict only example embodiments of the
invention and
are not intended to limit its scope in any way. Aspects of the invention will
be described
and explained with additional specificity and detail through the use of the
accompanying
drawings in which:
[0012] Figure 1 discloses aspects of an MD machine and associated MD
rolling
process;
[0013] Figure 2a is another detail view illustrating the formation of
indicia on a
portion of a film, a rib in this case, by a tool such as a ring roller;
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[0014] Figure 2b is a detail view of the MD machine of Figure 1, and
discloses
aspects of the operation of the MD machine relative to a film;
[0015] Figures 3a-1 and 3a-2 depict a first example of a film, referred
to herein as
Film 'A', suitable for use in constructing one or more discontinuously
laminated
structures, where the film in Figures 3a-1 and 3a-2 is an un-stretched film;
[0016] Figures 3U-1 and 3b-2 depict a first variation of Film 'A,'
where the film
has been ring rolled in the machine direction;
[0017] Figures 3c-1 and 3c-2 are another depiction of the first
variation of Film
'A,' where the film has been ring rolled in the machine direction;
[0018] Figures 3d-1 and 3d-2 depict a second variation of Film 'A,'
where the
film has been ring rolled first in the machine direction, and subsequently in
the transverse
direction;
[0019] Figures 4a-1 and 4a-2 depict a second example of a film,
referred to herein
as Film '13', suitable for use in constructing one or more discontinuously
laminated
structures, where the film in Figures 4a-1 and 4a-2 is an un-stretched film;
[0020] Figures 4b-1 and 4U-2 depict a first variation of Film '13,'
where the film
has been ring rolled in the machine direction;
[00211 Figures 4c-1 and 4c-2 depict a second variation of Film 'B,'
where the film
has been ring rolled first in the machine direction, and subsequently in the
transverse
direction;
[0022] Figures 5a-1 and 5a-2 depict a third example of a film, referred
to herein
as Film `C,' suitable for use in constructing one or more discontinuously
laminated
structures, where the film in Figures 5a-1 and 5a-2 is an un-stretched film;
[0023] Figures 5b-1 and 5b-2 depict a first variation of Film `C,'
where the film
has been ring-rolled in the machine direction;
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[0024] Figures 5c-1 and 5c-2 depict a second variation of Film `C,'
where the film
has been ring rolled first in the machine direction, and subsequently in the
transverse
direction;
[0025] Figures 6a-1 and 6a-2 depict a fourth example of a film,
referred to herein
as Film 'H,' suitable for use in constructing one or more discontinuously
laminated
structures, where the film in Figures 6a-1 and 6a-2 is an un-stretched film;
[0026] Figures 6b-1 and 6b-2 depict a first variation of Film `1-1,'
where the film
has been ring rolled in the machine direction;
[00271 Figures 6c-1 and 6c-2 depict a second variation of Film `1-1,'
where the
film has first been ring rolled in the machine direction, and subsequently in
the transverse
direction;
[0028] Figures 7-1 and 7-2 depict a first example of a discontinuously
laminated
film structure including a ribbed outer film and a black inner film;
[0029] Figures 8-1 and 8-2 depict a second example of a discontinuously
laminated film structure including a ribbed outer film having white ribs and
associated
indicia, and a black inner film;
[0030] Figures 9-1 and 9-2 depict a third example of a discontinuously
laminated
film structure including a ribbed outer film having white ribs and associated
indicia, and a
black inner film;
[0031] Figures 10-1 and 10-2 depict a fourth example of a
discontinuously
laminated film structure including a ribbed outer film having black ribs and
associated
indicia, and a white inner film;
[0032] Figures 11-1 and 11-2 depict a fifth example of a
discontinuously
laminated film structure including a ribbed outer film having black ribs and
associated
indicia, and a white inner film;
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[00331 Figure 12 is an example process suitable to form a
discontinuously
laminated film structure; and
[00341 Figure 13 is another example process suitable to form a
discontinuously
laminated film structure.
DETAILED DESCRIPTION
100351 Example embodiments of the invention generally concern laminated
polymer film structures. More particularly, at least some embodiments are
directed to
discontinuously laminated film structures with improved visual
characteristics, while
other embodiments arc directed to methods for producing such discontinuously
laminated
film structures. The films and discontinuously laminated film structures
disclosed herein
may be employed in a variety of different end products, examples of which
include, but
are not limited to, grocery bags, trash bags, sacks, yard waste bags,
packaging materials,
feminine hygiene products, baby diapers, adult incontinence products, sanitary
napkins,
bandages, food storage bags, food storage containers, thermal heat wraps,
facial masks,
wipes, and hard surface cleaners.
[00361 A. Aspects of Various Example Embodiments
100371 It should be noted that the embodiments disclosed herein do not
constitute
an exhaustive summary of all possible embodiments, nor does the following
discussion
constitute an exhaustive list of all aspects of any particular embodiment(s).
Rather, the
following discussion simply presents selected aspects of some example
embodiments. It
should likewise be noted that nothing herein should be construed as
constituting an
essential or indispensable element of any invention or embodiment. Rather, and
as the
person of ordinary skill in the art will readily appreciate, various aspects
of the disclosed
embodiments may be combined in a variety of ways so as to define yet further
embodiments. Such further embodiments are considered as being within the scope
of this
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disclosure. As well, none of the embodiments embraced within the scope of this
disclosure should be construed as necessarily resolving, or being limited to
the resolution
of, any particular problem(s). Nor should such embodiments be construed to
necessarily
implement, or be limited to implementation of, any particular effect(s).
[0038] Films and discontinuously laminated film structures within the
scope of
this disclosure may possess or exhibit a variety of different physical,
visual, and/or optical
characteristics. The visual and/or optical characteristics may be achieved
without the use,
for example, of metal layers, color generating laminates, delamination, and/or
bending of
the film structures. Moreover, such film structures do not require intimate
contact
between all portions of their films in order to provide such visual and/or
optical
characteristics.
[0039] Illustrative examples of effects such as visual appearances that
may be
manifest in various embodiments of a discontinuously laminated film structure
include: a
film with a ribbed outer layer, where a contrast in color and/or color
intensity is apparent
between the ribs and the webs between the ribs; a two-toned discontinuously
laminated
film structure with an outer film having silver or metallic webs interposed
between white
ribs, and a black inner film, such as may be produced by discontinuous
lamination of a
black inner film with a ribbed precursor film that is clear and has white
ribs; a
discontinuously laminated film structure with silver, metallic or grey webs
interposed
between black ribs, such as may be produced by discontinuous lamination of a
white
inner film with a ribbed precursor film that is clear and has black ribs; and,
a
discontinuously laminated film structure that includes a coextruded film with
an outer
layer having black ribs and white webs, and the coextruded film further
including a white
inner layer.
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100401 It should be noted that the aforementioned rib, web, and film
colors are
provided by way of example. Thus, for example, the inner film need not be
black, or
white, but may be any other color(s), and can be translucent, transparent, or
substantially
opaque.
[0041] As suggested by the foregoing general considerations,
discontinuously
laminated film structures and products within the scope of this disclosure may
include
one or more of the following, in any suitable combination: two or more films
discontinuously laminated to each other over at least a portion of each film;
two or more
films discontinuously laminated to each other over at least a portion of each
film, one of
the films being ribbed and manifesting a contrast in color and/or color
intensity between
the ribs and webs between the ribs; one or more ribbed films; one or more un-
ribbed
films; one or more inner films; one or more inner films with a coloring agent;
one or more
white inner films; one or more black inner films; one or more outer films; one
or more
outer films with a coloring agent; one or more substantially colorless outer
films; one or
more ribbed outer films; white ribs; black ribs; one or more plastic films;
one or more
thermoplastic films; ribs having a coloring agent; ribs having a voiding
agent; a first film
having a first region of discontinuous lamination with a second film, where a
substantial
portion of the first region is discontinuously laminated to the second film,
and the first
film also having a second region where a substantial portion of the second
region is in
intimate contact with the second film; and, an end product including any of
the foregoing
films, or combinations of those films.
[0042] It will be appreciated from the foregoing, and the other
disclosure herein,
that a variety of different embodiments may be defined. Some examples of such
embodiments are set forth below. Such embodiments are not intended to limit
the scope
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of the invention in any way.
[0043] In a first example embodiment, a discontinuously laminated film
structure
includes a ribbed precursor film laminated together with another film.
[00441 In a second example embodiment, a discontinuously laminated film
structure includes a ribbed precursor film, one example of which is a
coextruded ribbed
precursor film, laminated together with another film, and the ribbed precursor
film
includes a plurality of layers.
[0045] In a third example embodiment, a discontinuously laminated film
structure
includes a ribbed precursor film laminated together with another film, and the
ribbed
precursor film includes a plurality of layers of LLDPE
[0046] In a fourth example embodiment, a discontinuously laminated film
structure includes an extruded ribbed precursor film laminated together with
another film,
and the extruded ribbed precursor film exhibits a contrast in color ancUor
color intensity
between the ribs and the webs between the ribs.
[0047] In a fifth example embodiment, a discontinuously laminated film
structure
includes an extruded ribbed precursor film laminated together with another
film.
[0048] In a sixth example embodiment, a discontinuously laminated film
structure
includes a ribbed precursor film laminated together with another film, and the
ribs of the
ribbed precursor film are generally parallel to a machine direction.
[0049] In a seventh example embodiment, a discontinuously laminated
film
structure includes a ribbed precursor film laminated together with another
film, and the
discontinuously laminated film structure further includes one or more indicia
perceptible
by one or more senses of a user.
[0050] In an eighth example embodiment, a discontinuously laminated
film
structure includes an extruded ribbed precursor film laminated together with
another film,
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and the discontinuously laminated film structure further includes one or more
indicia
perceptible by one or more senses of a user.
100511 In a ninth example embodiment, a discontinuously laminated film
structure
includes a ribbed precursor film laminated together with another film, and the
discontinuously laminated film structure further includes one or more indicia
visually
perceptible by a user.
[0052] In a tenth example embodiment, a discontinuously laminated film
structure
includes a ribbed precursor film laminated together with another film that is
colored.
100531 In an eleventh example embodiment, a discontinuously laminated
film
structure includes a ribbed precursor film laminated together with another
film that is
black or white.
[0054] In a twelfth example embodiment, a discontinuously laminated film
structure includes a ribbed precursor film that includes one or both of a
stress-sensitive
coloring agent and a voiding agent and is laminated together with another
film.
[0055] In a thirteenth example embodiment, a discontinuously laminated
film
structure includes a ribbed precursor film that includes a stress-sensitive
agent and is
laminated together with another film.
[0056] In a fourteenth example embodiment, a discontinuously laminated
film
structure includes an extruded ribbed precursor film that includes a stress-
sensitive agent
and is laminated together with another film.
[0057] In a fifteenth example embodiment, a ribbed precursor film
includes a
stress-sensitive agent.
[0058] In further example embodiments, an end product includes any of
the
aforementioned discontinuously laminated film structures and/or precursor
films.
[0059] In a sixteenth example embodiment, a ribbed precursor film is
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discontinuously laminated together with another film and the resulting
discontinuously
laminated film structure is stretched.
100601 In a seventeenth example embodiment, a ribbed precursor film is
discontinuously laminated together with another film and the resulting
discontinuously
laminated film structure is stretched in one or both of an MD direction and a
TD
direction.
100611 In an eighteenth example embodiment, a ribbed precursor film is
discontinuously laminated together with another film and the resulting
discontinuously
laminated film structure is stretched first in an MD direction and then in a
TD direction.
100621 In a nineteenth example embodiment, a ribbed precursor film is
folded and
stacked on another folded film, and the stack is ring rolled, the ring rolling
including MD
or TD ring rolling, in any order.
[0063] In a twentieth example embodiment, a ribbed precursor film is
folded and
stacked on another folded film, and the stack is ring rolled, the ring rolling
including MD
or TD ring rolling, in any order, and then one film is inserted into the other
film, and the
resulting book structure is ring rolled, the ring rolling of the book
structure including MD
or TD ring rolling, in any order,
100641 In a twenty first example embodiment, a ribbed precursor film is
folded
and stacked on another folded film, and the stack is ring rolled, the ring
rolling including
MD or TD ring rolling, in any order, and then one film is inserted into the
other film, and
the resulting book structure is ring rolled, the ring rolling of the book
structure including
MD or TD ring rolling, in any order, and any of the ring rolling processes can
be hot or
cold processes.
[0065] In a twenty second example embodiment, a ribbed precursor film is
discontinuously laminated together with another film and the resulting
discontinuously
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laminated film structure is stretched so as to produce one or more indicia
perceptible by a
User.
[0066] In a twenty third example embodiment, a ribbed precursor film
including a
stress-sensitive agent is discontinuously laminated together with another film
and the
resulting discontinuously laminated film structure is stretched such that a
change
involving the stress-sensitive agent is perceptible by a user.
[0067] In a twenty fourth example embodiment, a ribbed precursor film is
discontinuously laminated together with another film and the resulting
discontinuously
laminated film structure is subjected to further processing which produces
indicia in the
discontinuously laminated film structure.
190681 In further example embodiments, any of the aforementioned
processes
used in whole or in part to produce an end product that includes any of the
aforementioned discontinuously laminated film structures and/or precursor
films.
[0069] For purposes of this disclosure and claims, the term "rib"
embraces a
portion of extra resin on a surface of a given precursor film, which portion
is an integral
portion of the film, and before any subsequent hot or cold forming process on
the film,
such as a ring rolling process. The "rib," e.g., reference 201 in Figure 1 of
a ribbed film,
e.g., reference 200 in Figure 1, may be formed in accordance with
implementations of the
present invention via extrusion of molten resin through an appropriate die
having one or
more sets of grooves for forming corresponding ribs. Similarly, for purposes
of this
description and claims, a "ribbed film" refers to a film that has been
extruded in molten
form with one or more ribs, and therefore comprises the one or more extruded
ribs
independent of any other striations or rib-like formations that may occur via
any other hot
or cold forming process after the initial extrusion/formation of the rib(s) of
the ribbed
film. Such other striations or rib-like formations from subsequent forming
processes are
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referred to herein generally as "ripples(s)." See, for example, reference 208
of Figures 1
and 2a.
100701 In teinis of the physical configuration of a "rib," the scope of
the invention
is not limited to any particular form, size or orientation thereof. In general
however, the
ribs extend outwardly a distance from a surface of the film. In this
structure, a web is
defined between consecutive ribs. The ribs may or may not have a generally
triangular
cross-section, but it will be appreciated that, for example, an extrusion die
can be
configured to produce a rib having any desired cross-sectional shape.
100711 B. Discontinuously Laminated Films and Film Structures
100721 As contemplated herein, discontinuously laminated structures and
discontinuous lamination processes embrace, among other things, lamination of
two or
more films where the lamination is not continuous, that is, the lamination is
discontinuous, in one or more directions. Such directions may include, for
example, one
or both of the machine direction (MD), and the transverse direction (TD) which
is
generally orthogonal to the MD. More particularly, discontinuous lamination
includes
lamination of two or more films with repeating bonded patterns broken up by
repeating
un-bonded areas in one or both of the machine direction and the transverse
direction of
the film.
[0073] As used herein, the term "machine direction" or "MD" refers to
the
direction along the length of the film, or in other words, the direction of
the film as the
film is formed during extrusion and/or coating. Likewise, the term "transverse
direction"
or "TD" refers to the direction across the film or perpendicular to the
machine direction.
Finally, the term "diagonal direction" or "DD" refers to the direction that is
not aligned
with either the length or the width of the film.
[0074] A wide variety of films and discontinuously laminated film
structures may
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be employed to achieve various desired visual characteristics and/or physical
characteristics, such as tactile characteristics. An
illustrative example of a
discontinuously laminated film structure includes at least two films, or
portions thereof,
that are discontinuously laminated to each other. That is, the two films
cooperatively
define both regions of intimate contact between the adjacent films, and
regions of non-
intimate contact between the adjacent films. The two or more films may include
a ribbed
film that is discontinuously laminated to a film that includes a coloring
agent and is un-
ribbed. One or more of the films of a discontinuously laminated film structure
may be
plastic or other flexible material(s). As well, one or more films of a
discontinuously
laminated film structure may be a coextruded, ribbed film, although other
example films
may be ribbed films may be used that are not produced by coextrusion. Thus,
the scope
of the invention is not limited to any particular type of ribbed film.
[0075] It
should be noted that in addition to being implemented together with one
or more other films to form a discontinuously laminated film structure, one or
more of the
ribbed films and other films included in the discontinuously laminated film
structure may,
themselves, also have a discontinuously laminated structure.
Accordingly,
discontinuously laminated film structures which include, as one of their
films, a film that
itself has a discontinuously laminated structure, are considered to fall
within the scope of
the invention.
[0076] C. Example Film Materials
[0077] The
discontinuously laminated film structures and their constituent films
may comprise any flexible or pliable material, including thermoplastic
materials that can
be formed or drawn into a film. As described above, discontinuously laminated
film
structures within the scope of the invention include a plurality of films, one
or more of
which may be thermoplastic. Each individual film may itself include a single
layer or
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multiple layers. Adjuncts may also be included, as desired. Examples of such
adjuncts
include coloring agents such as pigments, dyes, and dilute pigments, slip
agents, voiding
agents, anti-block agents, tackifiers, and combinations of the foregoing.
100781 The thermoplastic material of the films of one or more
implementations
can include, but are not limited to, thermoplastic polyolefins, including
polyethylene,
polypropylene, and copolymers thereof. Besides ethylene and propylene,
exemplary
copolymer olefins include, but are not limited to, ethylene vinylacetate
(EVA), ethylene
methyl acrylate (EMA) and ethylene acrylic acid (EAA), or blends of such
olefins.
[0079] Other examples of polymers suitable for use as films in
accordance with
the present invention include elastomeric polymers. Suitable elastomeric
polymers may
also be biodegradable or environmentally degradable. Suitable elastomeric
polymers for
the film include poly(ethylene-butene), poly(ethylene-hexene), poly(ethylene-
octene),
p0! y(ethylene-propylene),
poly(styren e-butadiene-styrene), poly(styrene-isoprene-
styrene), poly(styrene-ethylene-butylene-styrene), poly(ester-ether),
poly(ether-amide),
poly(ethylene-vinytacetate), poly(ethylene-methylacrylate), poly(ethylene-
acrylic acid),
poly(cthylene butyl acrylate), polyurethane, poly(ethylene-propylene-diene),
ethylene-
propylene rubber, and combinations of the foregoing.
[0080] D. General Aspects of Some Example Production Processes
[0081] Consistent with the varied natures of films and associated
discontinuously
laminated film structures, various processes, and combinations thereof, may be
used in
the production of the films and discontinuously laminated film structures
disclosed
herein. Examples of such processes include, but are not limited to, heat
bonding,
ultrasonic bonding, adhesive bonding, incremental stretching, pressure bonding
techniques such as machine direction (MD) ring rolling, transverse direction
(TD) ring
rolling, diagonal direction (DD) ring rolling, and any ring rolling process
that results in
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the formation of a laminated film with strainable networks. Treatment with a
corona
discharge may be used to enhance any of the aforementioned methods. Prior to
lamination, the separate films can be flat film or can be subject to separate
processes,
such as stretching, slitting, coating and printing, and corona treatment.
[0082] More generally however, any other process(es) that produces
laminated
films that cooperate to define regions of intimate contact between adjacent
films, and
regions of non-intimate contact between adjacent films, may be employed, and
the scope
of the invention is not limited to any particular production process(es).
Moreover, and as
noted above, various of the foregoing bonding techniques can be combined to
create a
film and/or discontinuously laminated film structures. By way of illustration,
pressure
and heat bonding processes can be combined, either simultaneously or serially,
to form a
film and/or discontinuously laminated film structure.
[0083] Consistent with this disclosure, manufacturers may form
individual films
to be discontinuously laminated together so as to provide improved strength
characteristics using a wide variety of techniques. For example, a
manufacturer can form
a precursor mix of the thermoplastic material including any optional
additives. The
manufacturer can then form the film(s) from the precursor mix using
conventional flat
extrusion, cast extrusion, or coextrusion to produce monolayer, coextruded
bilayer, or
multilayered films. In any case, the resulting film will be discontinuously
bonded to
another film at a later stage. Alternative to conventional flat extrusion or
cast extrusion
processes, a manufacturer can form the films using other suitable processes,
such as, a
blown film process to produce monolayer, bilayer, or multilayered films, which
are
subsequently discontinuously laminated with another film at a later stage. If
desired for a
given end use, the manufacturer can orient the films by trapped bubble,
tenterframe, or
other suitable processes. Additionally, the manufacturer can optionally anneal
the films.
17
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[00841 Where extrusion is employed, a manufacturer can use multiple
extruders to
supply different melt streams, which a feed block can order into different
channels of a
multi-channel die. The multiple extruders can allow a manufacturer to form a
multi-
layered film with films having different compositions. Such multi-layer film
may later be
discontinuously laminated with another film, which may or may not be multi-
layer itself,
to provide a discontinuously laminated film structure.
[0085] In a blown film process, the die can be an upright cylinder with
a circular
opening, and the die may include geometric features about its internal
diameter that can
form various structures on the film. As disclosed elsewhere herein, one
example of such
a geometric feature is a set of teeth disposed about the internal diameter of
the die which
may cause the formation of ribs on the film as the molten plastic is passed
through the
die. With continuing reference to the blow film process, rollers can pull
molten plastic
upward away from the die. An air-ring can cool the film as the film travels
upwards. An
air outlet can force compressed air into the center of the extruded circular
profile, creating
a bubble. The air can expand the extruded circular cross section by a multiple
of the die
diameter. This ratio may be referred to as the "blow-up ratio," or BUR. When
using a
blown film process, the manufacturer can collapse the film to double the plies
of the film.
Alternatively, the manufacturer can cut and fold the film, or cut and leave
the film
unfolded.
100861 A more detailed discussion of various specific examples of
production
processes that may be used in the production of the discontinuously laminated
film
structures disclosed herein is set forth below.
[00871 E. Example Production Equipment
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CA 2903883 2019-03-13
[0088] With reference now to Figures 1-2b, details are provided
concerning
aspects of a machine 100 that may be employed in conjunction with a film, such
as film
200 for example, to produce one or more of the ribbed films disclosed herein.
[0089] With regard initially to a film, the example film 200 may be a
multi-
layered film and may comprise any of the materials disclosed herein. For
example, the
film 200 may comprise two or more individual layers (not specifically shown in
Figures 1
and 2a), such as a ribbed precursor layer and other layers. The individual
layers of the
multi-layer film 200 may each be formed in whole or in part, by extrusion, for
example.
Moreover, a ribbed precursor film may include ribs 201 formed by an extrusion
process,
that is, extruded ribs. As indicated in Figure 1, the ribs 201 may extend
generally parallel
to the machine direction, but that is not required.
[0090] In any case, the film 200 can have an initial thickness or
starting gauge
202 defined by the distances between its top 204 and bottom surfaces 206. In
at least one
embodiment, the starting gauge 202, as well as the respective gauges of the
individual
layers can be substantially uniform along the length of the film 200.
[0091] With regard now to the machine 100, Figures 1 and 2a disclose
portions of
a machine 100 that can implement an MD ring rolling process that partially
discontinuously laminates individual adjacent layers of film 200 by passing
the film 200
through a pair of MD intermeshing rollers 102 and 104. As a result of MD ring
rolling,
the film 200 is also intermittently stretched in the machine direction MD.
[0092] For example, Figure 1 discloses that the first roller 102 and the
second
roller 104 can each have a generally cylindrical shape, and are operable to
rotate in
opposite directions about respective parallel axes of rotation 102a and 104a
that may be
generally parallel to the transverse direction TD and generally perpendicular
to the
machine direction MD. The rollers 102 and 104 each include a respective
plurality of
19
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radially protruding ridges 106 and 108 that extend along the respective
rollers 102 and
104 in a direction generally parallel to the axes of rotation 102a and 104a.
The respective
tips 106a and 108a of ridges 106 and 108 can have a variety of different
shapes and
configurations, including the rounded shape as shown in Figure 2a. In
alternative
implementations, the tips 106a and 108a of the ridges 106 and 108 can have
sharp angled
corners. As further indicated in Figures 1 and 2a, the ridges 106 are
separated by grooves
110, while the ridges 108 arc separated by grooves 112.
[0093] In at least one implementation, the ridges 106 and 108 are
staggered
relative to each other so that the grooves 110 can receive at least a portion
of the ridges
108 as the rollers 102 and 104 intermesh with each other. Correspondingly, the
grooves
112 can receive at least a portion of the ridges 106. In at least some
instances, the
configuration of the ridges 106 and 108 and grooves 110 and 112 can prevent
substantial
contact between ridges 106 and 108 during intermeshing such that little or no
rotational
torque is transmitted during operation. Additionally, the configuration of the
ridges 106
and 108, and of the grooves 110 and 112, can affect the amount of stretching
and the
bond strength resulting from partially discontinuous lamination as the film
passes through
the rollers 102 and 104.
100941 With continued reference to Figures 1 and 2a, the pitch and depth
of
engagement of the ridges 106 and 108 can determine, at least in part, the
amount of
incremental stretching and partially discontinuous lamination caused by the
intermeshing
rollers 102 and 104. As shown in Figure 2a, the pitch 114 is the distance
between the tips
of two adjacent ridges on the same roller. The depth of engagement (DOE) 116
is the
amount of overlap between adjacent ridges 106 and 108 of the rollers 102 and
104 during
intermeshing.
CA 2903883 2019-03-13
[0095] As is
evident from the foregoing, various parameters of the machine 100
may be selected and implemented depending upon the effect(s) desired to be
achieved.
For example, the ridge pitch and/or DOE may be varied as necessary. Merely
because
these parameters, and others, may be varied however, such variations will not
necessarily
be evident to one of ordinary skill in the art, and may, in some instances at
least, be
arrived at only after substantial experimentation and trials.
[0096] As
indicated in Figures 1 and 2a, the direction of travel of the film 200
through the intermeshing rollers 102 and 104 is generally parallel to the
machine
direction and generally perpendicular to the transverse direction. As the
multi-layered
film 200 passes between the intermeshing rollers 102 and 104, the ridges 106
and 108
incrementally stretch the film 200 in the machine direction. In one
or more
implementations, stretching the film 200 in the machine direction can reduce
the gauge of
the film and increase the length of the film 200. In other implementations,
the film 200
may rebound after stretching such that the gauge of the film 200 is not
substantially
decreased. Furthermore, in one or more implementations, stretching the film
200 in the
machine direction can reduce the width of the film 200. For example, as the
film 200 is
lengthened in the machine direction, the width of the film 200 can be reduced
in the
transverse direction.
[0097] In
particular, and as best shown in Figure 2a, as the film 200 proceeds
between the intermeshing rollers 102 and 104, the ridges 106 of the first
roller 102 can
push film 200 into the grooves 112 of the second roller 104, and the ridges
108 of the
second roller 104 can also push the film 200 into the grooves 110 of the first
roller 102.
The pulling of the film 200 by the ridges 106 and 108 can stretch the film
200. However,
the rollers 102 and 104 need not necessarily stretch the film 200 evenly along
its length.
Specifically, the rollers 102 and 104 can stretch the portions of the film 200
between the
21
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=
ridges 106 and 108 more than the portions of the film 200 that contact the
ridges 106 and
108, as indicated in Figure 2a.
[0098] Thus, the rollers 102 and 104 can cooperate to foim a series of
machined
ripples 208 in the film 200 such that the film 250 includes relatively thicker
portions
alternating with relatively thinner portions. As indicated in Figure 1, the
ripples 208 in
this particular example are disposed generally parallel to the transverse
direction. In this
example then, the ripples 208 arc generally orthogonal to the ribs 201, but
such an
arrangement is not required. Thus, the finished film 200 may be a rippled film
of multi-
layer, or single layer, construction. Moreover, the finished film 200 may, in
at least some
embodiments, have a laminated structure, although such a structure is not
required nor
implemented in every case. As disclosed elsewhere herein, various desirable
visual
effects and characteristics may be achieved through selection and processing
of various
films that make up a multi-layer implementation of the film 200.
[0099] Directing attention now to Figure 2b, and with continuing
attention to
Figure 2a, details are provided concerning aspects of an example machine and
process
which may be useful in creating various indicia on a film, such as a ribbed
film for
example. In particular, it can be seen that when an MD ring rolling process,
for example,
is performed on the example film 200, the ridges 106 and 108 may temporarily
or
permanently compress portions of the ribs 201. The compressions 210 may, but
need not,
be generally orthogonal to the direction of the ribs 201.
[00100] It will be appreciated that the compressions 210 of the ribs
201 constitute
one example of indicia, discussed in more detail elsewhere herein. The color,
size,
number, geometry and orientation of the compressions 260 may depend on one or
more
of the particular ring rolling process performed, roller pitch, DOE,
material(s) of the film,
and pigments and/or voiding agents present in one or more films.
22
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[00101] A stretching process such as MD ring rolling is one example of
method
suitable to implement partially discontinuous lamination of a film, such as a
multi-layer
film for example, by incremental stretching of the film in the machine
direction. A
stretching process such as TD ring rolling is another suitable method of
discontinuously
or partially discontinuously laminating a film such as a multi-layer film for
example, by
incremental stretching of the film in the transverse direction. Stretching
processes such as
TD ring rolling and MD ring rolling, may be used together, alone, or in
conjunction with
other processes. While not specifically illustrated, a TD ring rolling machine
and
associated process may be similar, respectively, to the MD ring rolling
machine and
associated process, though the rollers of a TD ring rolling machine include
ridges and
grooves that extend generally parallel to the MD direction, rather than
orthogonal to the
MD direction, as in the case of an MD machine and process. Thus, a TD ring
rolling
process may produce a film having corrugations that are generally parallel to
the MD
direction.
[00102] F. Example Films
[00103] In general, there arc a variety of films that may be employed in
the
formation of discontinuously laminated film structures and, accordingly, it
should be
understood that the embodiments of films and discontinuously laminated film
structures
set forth in the Figures, and discussed herein, are presented solely by way of
illustration
and are not intended to limit the scope of the invention in any way. The
example films
discussed below are ribbed films that may be produced in a variety of
different ways. In
addition to a visually appealing appearance, such ribs may provide a structure
that
deforms, thereby producing indicia, when subjected to various stretching
processes, such
as DD, MD, and TD ring rolling. As noted elsewhere herein, variables such as
pitch of
ribs, DOE, and/or RR teeth can be adjusted to provide desirable visual effects
in the film.
23
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[00104] F.1 Example Film 'A'
[00105] Figures 3a-1 through 3d-2 and the corresponding text provide
details
concerning an example ribbed film laminate structure referred to herein as
Film 'A.' In
Figures 3a-1, 3b-1, 3c-1 and 3d-1, the left-side portion of the film is shown
on a white
background, and the right-side portion of the film is shown on a black
background, to
better disclose various aspects of the film. The same is likewise true of
Figures 4a-1, 4b-
1, 4c-1, 5a-1, 5b-1, and 5c-1. In Figures 6a-1, 6b-1 and 6c-1, only a black
background is
used.
[00106] In this particular example, Film 'A' is an extruded film that
comprises
three layers of linear low-density polyethylene (LLDPE), having a layer
structure of
A:B:A, wherein the layer ratio for the three layers is about 20:60:20. That
is, the outer
two layers, or skin layers, each have a thickness of about 20 percent of the
total thickness
of Film 'A', while the core layer has a thickness of about 60 percent of the
total thickness
of Film 'A'.
[00107] Figures 3a-1 through 3d-2 further show that both the core layer
and the
skin layers are un-pigmented. The ribs of Film 'A' averaged about 6.5 mils
tall, with an
average spacing between extruded ribs 302 of about 0.336 inches. The thickness
of the
web 304 between consecutive extruded ribs 302 was targeted to be about 0.50
mils thick.
As indicated in the Figures, the extruded ribs 302 appear translucent as a
result of their
relative thickness, and as a result of its thinness, the web 304 between the
extruded ribs
302 appears to be nearly colorless.
[00108] With particular reference first to Figures 3a-1 and 3a-2, an
embodiment of
Film 'A' is disclosed that reflects an absence of post-extrusion processing,
such as MD or
TD ring rolling. As illustrated, the ribs 302 have a hazy appearance, and the
web 304
between the ribs 302 is largely translucent.
24
CA 2903883 2019-03-13
[00109] Figures 3U-1, 3b-2, 3c-1 and 3c-2 further disclose that different
effects can
be achieved in, for example, the appearance and/or feel of a ribbed film by
varying the
post-extrusion tools and/or processing employed in connection with the film.
Such tools
and/or processing can include one or more of DOE, tooth pitch, tooth shape,
and ring
rolling including one or more of TD, MD and DD ring rolling. To illustrate,
Figures 3b-
1, 3b-2, 3c-1 and 3c-2 disclose an implementation in which Film 'A was
stretched by an
MD process using a 200 pitch tool and a DOE of about 150 mils. MD stretching
with
these parameters resulted in the web 304 having a hazier appearance, relative
to the un-
stretched embodiment of Figures 3a-1 and 3a-2, while the ribs 302 experienced
no
substantial change in color or haze. This is particularly apparent when
referring to the
right hand side of Figures 3a-1, 3a-2, 3U-1 and 3b-2, where Film 'A' is
disposed on a
black background.
[00110] Figures 3d-1 and 3d-2 disclose the embodiment of Figures 3b-1, 3b-
2, 3c-1
and 3c-2 after that embodiment was further subjected to a TD ring rolling
process with a
40 pitch tool and DOE of about 20 mils. The additional TD ring rolling process
produced
no substantial change in the haze of the web 304 between the ribs 302.
Similarly, this
process produced no substantial color change in the extruded ribs 302 or web
304
between the extruded ribs 302.
[001111 F.2 Example Film 'B'
[00112] Figures 4a-1 and 4a-2 disclose aspects of another film referred
to herein as
Film 'B,' before any ring rolling, such as TD or MD ring rolling, has been
performed.
Similar to Film 'A,' Film 'B' is an extruded, ribbed film laminate structure
that comprises
three layers of linear low-density polyethylene (LLDPE) having a layer
structure of
A:B:A, where the layer ratio for the three layers is about 20:60:20.
CA 2903883 2019-03-13
1001131 In this example, the core layer (or 'B' layer of the A:B:A
structure)
is un-pigmented, but in contrast with Film 'A,' the skin layers contain about
20 percent
calcium carbonate (CaCO3) masterbatch, a voiding agent. As in the case of Film
'A', the
ribs 402 of Film 'B' average about 6.5 mils tall, with an average spacing
between ribs 402
of about 0.336 inches. The thickness of the web 404 between the ribs 402 was
targeted to
be about 0.50 mils thick. The example of Fig. 4a indicates that, absent any
ring rolling,
the ribs 402 of Film 'B' have a hazy translucent appearance due to the
presence of the
CaCO3 and the thickness of the ribs 402, while the web 404 between the ribs
402 was
hazy but nearly colorless.
[00114] Figures 4b-1 and 4b-2 indicate the effect on Film 'B' of the
performance of
an MD ring rolling process. In particular, Figure 4b illustrates the effect on
Film 'B' after
application of an MD ring rolling process using a 200 pitch tool and a DOE of
about 150
mils. As shown in that Figure, MD ring rolling and consequent stretching of
Film 'B'
under these parameters resulted in a relatively hazier appearance of the web
404 between
the ribs 402, while the ribs 402 took on a visibly enhanced white color.
Figures 4b-1 and
4b-2 further show that the ribs 402 each comprise a white "stitch" or cross
pattern that
intermittently crosses each rib 403. This is particularly apparent when
referring to the
right hand side of Figures 4b-1 and 4b-2, where Film '13' is disposed on a
black
background. The "stitch" patterns are areas in which the MD rollers stress
that particular
area of the rib 402, causing the voiding agent, which is stress-sensitive, to
react and
produce areas of enhanced whiteness along the ribs 402. As in the case of Film
'A' in
Figures 3a-1 through 3c-2, however, the stretching resulting from the TD ring
rolling
process has no such effect on the MD ring rolled Film 'B.' As discussed in
more detail
below, the aforementioned stitches are one example of indicia that may be
produced in
connection with various embodiments.
26
CA 2903883 2019-03-13
[001151 Notably, Figures 4c-1 and 4c-2 illustrate Film 'B' after the
application, to
the film of Figures 4b-1 and 4b-2, of a TD process using a 40 pitch tool and a
DOE of
about 20 mils. As indicated, that TD process produced no significant change in
the ribs
402, or in web 404.
[00116] F.3 Example Film 'C'
[00117] Figures 5a-1 through 5c-2 provide details concerning another
example
ribbed film, referred to herein as Film 'C.' In this particular example, Film
'C' is an
extruded ribbed film that comprises three layers of linear low-density
polyethylene
(LLDPE), having a layer structure of A:B:A, wherein the layer ratio for the
three layers is
about 20:60:20. As in the case of Films 'A' and 'B,' discussed above in
connection with
Figures 3a-1 through 4c-2, the ribs 502 of Film 'C' average about 6.5 mils
tall, with an
average spacing between ribs 502 of about 0.336 inches. The thickness of the
web 504
between the ribs 502 was targeted to be about 0.50 mils thick.
[00118] In contrast with Film 'B,' however, Film 'C' comprises a black
coloring
agent that causes the ribs 502 to appear black. Specifically, Film C comprises
a core
layer (layer B of layer structure A:B:A) that was un-pigmented, albeit with
skin layers
(layers A of structure A:B:A) that contained a dilute pigment, about 0.5
percent black
masterbatch in this example. By way of explanation, Applicants have found that
a dilute
pigment having a concentration in the range of about 0.25 percent to about 3.0
percent
may provide acceptable results in this and/or other embodiments. Applicants
have also
found that concentrations in a range of about 0.25 percent to about 2.0
percent may be
useful in some instances, and concentrations in a range of about 0.25 percent
to about 1.0
may be particularly useful in some instances.
[00119] With particular reference to Figures 5a-1 and 5a-2, which
disclose an un-
stretched version of Film 'C,' the ribs 502 appear black due to their
thickness and the
27
CA 2903883 2019-03-13
presence of the black masterbatch. Due to its relative thinness, the web 504
between the
ribs 502 can appear to be nearly colorless to slightly hazy.
[00120] Figures 5b-1 and 5b-2, however, show the effects of applying an
MD
stretching process, to the film of Figures 5a-1 and 5a-2, where the ribs 502
are colored,
but otherwise comprise no voiding agents that might change or enhance color
with stress.
The MD ring rolling was performed using a 200 pitch tool and a DOE of about
150 mils.
Specifically, Figures 5b-1 and 5b-2 show that applying MD stretching under
these
parameters can produce some intermittent deformation of the film at uniform
points along
the ribs 502, and a corresponding hazier appearance of the ribs 502, but
otherwise
produce no color change to the ribs 502. Similarly, the web 504 can become
hazier as
well, but otherwise undergo no color change. The additional application, to
the film of
Figures 5b-1 and 5b-2, of a TD process using a 40 pitch tool and a DOE of
about 20 mils
produced no discernible change in the ribs 502 or intervening film 504, as
indicated in
Figures 5c-1 and 5c-2. As discussed in more detail below, the aforementioned
intermittent deformation of the ribs 502 is another example of indicia that
may be
produced in connection with various embodiments.
[00121] F.4 Example Film 'H'
[00122] Figures 6a-1 through 6c-2 and the corresponding text provide
details
concerning an example ribbed film referred to herein as Film `H.' As indicated
in those
figures, Film `H' is a ribbed film. In this particular example, Film 'H' is an
extruded film
that comprises three layers of linear low-density polyethylene (LLDPE). In
this example,
Film 'H' has a layer structure of A:B:A. The layer ratio for the three layers
is about
20:60:20.
[00123] In this example, the core layer comprised about 6 percent black
masterbatch, and the skin layers contained about 20 percent CaCO3 masterbatch.
The
28
CA 2903883 2019-03-13
ribs 602 of Film 'I-1' averaged about 6.5 mils tall, with an average spacing
between ribs
602 of about 0.336 inches. The thickness of the intervening film 604 between
the ribs
602 was targeted to be about 0.50 mils thick.
1001241 Observation of Film 'H' in Figures 6a-1 and 6a-2 reveals hazy,
gray
colored ribs, and black film between the ribs. The sample of Figures 6a-1 and
6a-2 was
not subjected to any post-extrusion processing. In the sample of Figures 6b-1
and 6U-2,
which reflects application of an MD stretching process with a 200 pitch tool
at a DOE of
about 150 mils, the ribs 602 have a white, stitched appearance, and the black
film
between the ribs 602 remains black. As indicated in Figures 6c-I and 6c-2, a
TD
stretching process, with a 40 pitch tool at about 20 mils DOE, performed
subsequent to
the MD stretching process resulted in no color change to the ribs 602 or to
the film
between the ribs 62, as compared with the film of Figures 6b-1 and 6b-2.
[00125] G. Example Discontinuously Laminated Film Structures
[00126] As noted above, the various films, including ribbed films,
disclosed herein
may be employed in the construction of discontinuously laminated film
structures.
Following is a discussion of eight example, discontinuously laminated film
structures that
each employ one of the example films disclosed herein. The
aforementioned
discontinuously laminated film structures are presented only by way of example
and are
not intended to limit the scope of the invention in any way. With attention
now to Figures
7-11, details are provided concerning some example discontinuously laminated
film
structures.
[00127] G.1 Structure 1
[00128] Directing attention first to Figures 7-1 and 7-2, Discontinuously
Laminated
Film Structure 1 (Structure 1) production parameters included MD RR,
Insertion, TD RR.
Structure 1 was created with the outer layer being un-stretched ribbed Film
13' described
29
CA 2903883 2019-03-13
above in connection with Figures 4a-4c. The inner layer was a 0.5 mil 0.920
density
LLDPE black film containing approximately 5 percent carbon black masterbatch.
Prior
to insertion of the black inner film into the outer film, the C-folded films
were stacked
one upon the other and MD ring rolled at 190 DOE with a 200 pitch tool. The
black inner
film was then inserted into the un-pigmented outer film and the composite TD
ring rolled
at 20 DOE with a 40 pitch tool.
[00129] On viewing the laminated structure, Structure 1 appeared as two
toned,
having white ribs 702 interconnected by metallic or silver webs 704 on the
outside with a
black inner film 706. In addition, the white ribs 702 were visually
discontinuous, with a
small white "star" or dot 708 on the rib 702 where the MD tool contacted the
rib 702.
[00130] G.2 Structure 2
[00131] Directing attention now to Figures 8-1 and 8-2, Discontinuously
Laminated Film Structure 2 (Structure 2) production parameters included
Insertion, MD,
and TD RR. Structure 2 was created with the outer film being un-stretched
ribbed Film
'IV described above. The inner film was a 0.5 mil 0.920 density LLDPE black
film
containing about 5 percent carbon black MB. The black inner film was inserted
into the
un-pigmented ribbed outer film, and the resulting composite structure was then
MD ring
rolled at 190 DOE with a 200 pitch tool, followed immediately by TD ring
rolling at 20
DOE with a 40 pitch tool. In embodiments such as this, namely, where insertion
is
performed prior to any ring rolling process, this sequence of insertion and
ring rolling
may be advantageous inasmuch as insertion of films prior to ring rolling can
help to better
maintain the structural integrity of the involved films, and also help reduce
the presence
of entrained air between the films.
[00132] On viewing the laminated structure, Structure 2 appeared as being
two
toned, having white ribs 802 interconnected by metallic-looking webs 804 on
the outside
CA 2903883 2019-03-13
with a black inner film 806. In addition, the white ribs 802 were visually
discontinuous,
with a small white -star" or dot 808 on the rib 802 where the MD tool
contacted the rib
802. Furthermore, there were black "stitch" marks 810 on the interconnected
webs 804
adjacent on either side of the white stars 808 on the ribs 802.
[00133] G.3 Structure 3
[00134] Directing attention now to Figures 9-1 and 9-2, Discontinuously
Laminated Film Structure 3 (Structure 3) production parameters included
Insertion, and
MD RR. Structure 3 is the same as Structure 2 described above except without
TD RR.
[00135] The appearance of Structure 3 was similar to as described in
Structure 2
above, except the webs 902 between the ribs 904 alternate in and out of plane
in a
strongly visible zigzag manner in the machine direction. Also, Structure 3 was
thicker
than Structure 2, owing to lack of TD stretching in the production of
Structure 3.
[00136] G.4 Structure 4
[00137] Directing attention now to Figures 10-1 and 10-2, Discontinuously
Laminated Film Structure 4 (Structure 4) production parameters included MD RR,
Insertion, and TD RR. Structure 4 was created with the outer film being un-
stretched
ribbed Film C described above.
1001381 The inner film was a 0.5 mil 0.920 density LLDPE white film
containing
approximately 5 percent white MB. Prior to insertion of the white inner film
into the
outer ribbed film, the C-folded films were stacked one upon the other and MD
ring rolled
at 190 DOE with a 200 pitch tool. The white inner film was then inserted into
the ribbed
outer film and the resulting composite TD ring rolling at 20 DOE with a 40
pitch tool.
[00139] On viewing the laminated structure, Structure 4 appeared as being
two
toned, having black ribs 1002 interconnected by silver webs 1004 on the
outside with a
white inner film 1006. In addition, the black ribs 1002 appeared
discontinuous, with an
31
CA 2903883 2019-03-13
apparent -break" in the rib 1002 occurring where the MD tooth contacted the
rib 1002,
creating a "stitched" appearance of the ribs 1002.
[00140] G.5 Structure 5
[00141] Directing attention now to Figures 11-1 and 11-2, Discontinuously
Laminated Film Structure 5 (Structure 5) production parameters included
Insertion, MD,
and TD RR. Structure 5 was created with the outer film being un-stretched Film
C
described above. The inner film was a 0.5 mil 0.920 density LLDPE white film
containing approximately 5% white MB. The white inner film was inserted into
the
ribbed outer film and the resulting composite structure then MD ring rolled at
190 DOE
with a 200 pitch tool, followed immediately by TD ring rolling at 20 DOE with
a 40 pitch
tool.
[00142] On viewing the laminated structure, the composite structure
appeared as
being two toned, having black ribs 1102 interconnected by silver webs 1104 on
the
outside with a white inner film 1106. In addition, the black ribs 1102
appeared
discontinuous, with an apparent "break" in the rib 1102 occurring where the MD
tooth
contacted the rib 1102, creating a "stitched" appearance in the ribs 1102.
Furthermore,
the webs 1104 between the ribs 1102 appear to alternate in and out of plane in
a zigzag
manner in the machine direction.
1001431 3.6 Structure 6
[00144] Discontinuously Laminated Film Structure 6 (Structure 6)
production
parameters included Insertion, and MD RR. Structure 6 is the same as Structure
5
described above except without TD RR.
[00145] The appearance of Structure 6 was similar to that of Structure 2
described
above, except the webs between the ribs alternate in and out of plane in a
strongly visible
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zigzag manner in the machine direction. Also, the composite film was thicker
owing to
lack of TD stretching.
[00146] G.7 Structure 7
[00147] Discontinuously Laminated Film Structure 7 (Structure 7)
production
parameters included Insertion, and 100 Pitch MD RR.
[00148] The appearance of Structure 7 was the same as Structure 6
described above
except with finer MD tool markings on the ribbed outer film, resulting in a
tighter pitched
stitched appearance. In addition, in Structure 7, the pitch of the webs
between the ribs
alternating in and out of plan is finer, resulting in a tighter, more pleasing
zigzag pattern.
This tighter zigzag pattern appears to enhance and intensify the silver color
compared to
Structure 7 above.
[00149] G.8 Structure 8
[00150] Discontinuously Laminated Film Structure 8 (Structure 8)
production
parameters included Insertion, 100 Pitch MD, and TD RR. The appearance of
Structure 8
was the same as Structure 7 above except that TD RR was applied after the MD
RR. The
TD RR modulates the amplitude of the in and out of plane zigzag pattern in the
webs
between the ribs. This pattern results in a slightly less intense silver color
compared to
Structure 7 above.
[00151] H. Examples of Production Processes and Resulting 1ndicia
[00152] As will be apparent from the foregoing discussion and example
films and
structures, various processes may be employed to provide indicia that may
convey
information to a user concerning an end product in which the film and/or
structure is
employed.
[00153] H.1 Example Production Processes
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[00154] As noted earlier, at least some of the processes that may be
employed to
create the discontinuously laminated film structures disclosed herein
generally involve the
bonding of ribbed first film portion to a second un-ribbed film portion so as
to define a
region of discontinuous lamination between the first film portion and the
second film
portion. The region of discontinuous lamination comprises both a plurality of
regions
where the first and second film portions are bonded together, and a plurality
of regions
where the first and second film portions arc not bonded together.
[00155] With attention now to Figures 12 and 13, examples of some
discontinuous
lamination processes are set forth in detail. In should be noted that while
certain
processes are described as being performed in a particular order, such
description is not
intended to limit the scope of the invention. Rather, the recited processes
may be
performed in any suitable order and, moreover, additional or alternatives to
any of the
processes may be employed. Moreover, all of the recited processes need not be
performed. Rather, one or more of the processes may be omitted.
[00156] Directing attention first to Figure 12, an example process 1200
is disclosed
that may be used to form, for example, Structures 1, 4 and 5 disclosed herein.
[00157] Process 1200 begins at 1202 where a first film is folded, such as
by C-
folding for example. At 1204, a second film is folded, such as by C-folding
for example.
In at least some embodiments, the outer film, whether it is the first or
second film, is a
ribbed precursor film formed by a process such as extrusion. In those and/or
other
embodiments, the inner film may have an opaque color, such as black or white,
for
example, although other colors may be used. As well, the ribbed precursor film
may
include colors such as black or white, for example, in one or both of the ribs
and webs
between the ribs. In some instances, the C-folding process, or other folding
process, may
be omitted.
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[001581 The
folded first film and folded second film are then stacked 1206 to form
a film stack. At 1208, the film stack is processed, such as by a cold or hot
rolling process.
In either case, the rolling process may be an MD ring rolling process,
although other
rolling processes such as TD and/or DD ring rolling could additionally, or
alternatively,
be employed. At 1210, one of the C-folded films, which could be either the
first or
second film, is inserted into the other C-folded film, which could be either
the first or
second film, so as to form a film 'book' configuration. Where an MD ring
rolling process
is performed on the film book, the film book may assume a corrugated
appearance, with
corrugations that are generally perpendicular to the extruded ribs of the
outer layer.
1001591 Finally, at 1212, the film book is ring rolled. In at
least some
embodiments, a TD ring rolling process is used. However, other ring rolling
processes
may additionally or alternatively be employed.
[00160] In one
variation of process 1200, the final TD ring rolling process 1212 is
omitted. This variation may be used to form, for example, Structure 6
disclosed herein.
In another variation, the TD ring rolling process 1212 immediately follows the
MD ring
rolling process 1208. This latter variation may be used to form, for example,
Structure 8
disclosed herein.
[001611
Directing attention now to Figure 13, an example process 1300 is
disclosed that may, for example, be used to form Structure 2 disclosed herein.
[00162]
Process 1300 begins at 1302 where an inner film is inserted into an outer
film to form, for example, a film book. The inner film may be a black film,
and the outer
film may be a ribbed precursor film, although different inner and/or outer
films could be
used. At 1304, the film book is ring rolled, such as by MD ring rolling for
example.
Thereafter, at 1306, the MD ring rolled film book is ring rolled, such as by
TD ring
rolling for example.
CA 2903883 2019-03-13
[001631 As noted above, variations of the processes disclosed herein are
possible.
Accordingly, in at least one alternative embodiment, the TD ring rolling
process may be
omitted from process 1300.
1001641 H.2 Example indicia and Their Formation
[00165] In connection with the processes disclosed herein, including
those set forth
in Figure 12 and 13, various physical indicators may result from the
performance of those
processes and/or may be present in precursor films used in such processes.
Consistent
with the foregoing, and as set forth in the discussion of the structures
below, such indicia
may include, for example, elements such as colors, dyes, pigments, textures,
ribs,
corrugations, stars, dots, bars, stitches, discontinuous lines, and
combinations of any of
the foregoing. Not only are such indicia readily apparent to a user of, for
example, an end
product in which the discontinuously laminated film structure is employed, but
such
indicia may be advantageous insofar as they are perceptible by one or more
senses of a
user.
[00166] Various types of indicia may be present in a particular end
product,
discontinuously laminated film structure, or precursor film. For example, one
type of
indicia may convey to a user certain information concerning an attribute of an
end
product. Another type of indicia may serve a largely cosmetic or aesthetic
purpose. The
foregoing and/or other types of indicia may be combined, for example, in a
single end
product.
[00167] By way of illustration, indicia may indicate visually, and/or in
a tactile
sense, certain attributes of the end product such as, for example, a relative
strength of the
product. Thus, the extruded ribs present in a precursor film enhance the
strength of the
precursor film. As well, such extruded ribs also provide a visible and tactile
indicator, to
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a user, of the strength of the film and/or the strength of a discontinuously
laminated film
structure or end product in which that film is employed.
1001681 As another example, the stars or dots present in some of the
'Structures'
noted below serve as an indicator of highly localized stress whitening, such
as may be
obtained with various combinations of ring rolling processes, such as MD
and/or TD ring
rolling. The highly localized stress whitening, which may result from ring
rolling in a
direction generally orthogonal to a direction of extruded ribs of a film, can
serve as an
indicator to a consumer as to the strength of the discontinuously laminated
film structure,
since the localized stress whitening occurs at points where the extruded ribs
are worked
by the teeth of a roller.
1001691 Moreover, the formation of indicia, such as color intensification
in the
form of localized stress whitening, or can be localized and controlled using
various
combinations of voiding agents, coloring agents such as dyes and pigments, and
various
stretching processes such as hot and/or cold MD and/or TD ring rolling.
Indeed, such
whitening can be highly localized, if desired, as evidenced by indicia such as
the dots and
stars disclosed elsewhere herein. More generally, stress-sensitive agents such
as voiding
agents, and coloring agents such as dyes and pigments, can be employed in one
or more
films of a discontinuously laminated film structure such that formation of the
films and/or
the discontinuously laminated film structure causes a change to the element(s)
that
include the agent, thereby providing a visible manifestation of induced stress
and/or
strain.
[00170] As noted above, some indicia within the scope of this disclosure
may be
largely cosmetic or aesthetic in nature. For example, MD ring rolling of the
extruded ribs
in a ribbed precursor film provides an interesting visual effect that may have
little to do
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with the strength or integrity of the precursor film or associated
discontinuously
laminated film structure.
1001711 Finally, and with regard to the foregoing discussion, it will be
apparent
that insofar as indicia convey to a user information concerning a property of
a precursor
film, discontinuously laminated film structure, and/or end product, such
indicia are
example implementations of means for conveying information perceptible by a
sense of a
user. Thus, the indicia disclosed herein arc provided solely by way of
example, and any
other indicia of comparable functionality may alternatively be employed.
1001721 In light of the disclosure herein, it will be appreciated that
embodiments of
the invention may be advantageous in various ways relative to conventional
structures
and processes. Below are set forth various examples of some advantages that
may be
achieved in connection with one or more embodiments of the invention. It is
not
necessary that all of such examples be present in any particular embodiment,
nor is it
necessary that any particular example be present in an embodiment. Finally, it
should be
noted that the examples set forth below are provided solely by way of
illustration and are
not intended, nor should be construed, to limit the scope of the invention in
any way.
[001731 1. Example Advantages of Some Embodiments
1001741 With regard now to some possible advantages of example
embodiments,
one or more embodiments of the invention may substantially maintain their
color
characteristics, notwithstanding temporary or permanent deformation of the
film. As
another example, one or more embodiments of the invention may implement
various
visual effects, such as coloration, with non-metallic films. As a further
example, one or
more embodiments of the invention may implement various visual effects such as
coloration without the use of color-generating laminates or films. As yet
another
example, one or more embodiments of the invention may provide visual effects
such as
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coloration without requiring user manipulation, such as by bending or
delamination for
example, with regard to the finished film. Moreover, one or more embodiments
of the
invention may implement desired visual effects with discontinuously laminated
films, and
thus do not require intimate contact between films. As well, one or more
embodiments of
the invention may implement desired visual effects with film structures that
include at
least one ribbed film.
[00175] Further, one or more embodiments of the invention may realize a
relative
increase in strength as a result of MD rolling and/or TD rolling of a ribbed
precursor film
or a laminated film that includes such a rolled precursor film. Moreover, the
relative
strength of the film and/or of a product that employs the film may be visually
indicated to
a user by indicia such as a color, color intensification such as by imposition
of stress or
strain, contrasting colors, and/or distribution of the color in the film or
product. As
another example, the incremental stretching processes disclosed herein, such
as TD and
MD ring rolling for example, may be advantageous over conventional continuous-
stretch
processes that do not produce indicia and the other effects noted herein. As a
final
example, one or more of the embodiments disclosed herein may be advantageous
inasmuch as they possess, or produce, as applicable, indicia using a
continuous process.
More conventional processes, such as stamping or embossing, are not well
suited to be
implemented in a continuous fashion. Rather, only discrete portions of the
film can be
stamped or embossed.
[00176] The present invention may be embodied in other specific forms
without
departing from its spirit or essential characteristics. For example, the
illustrated and
described implementations involve non-continuous (i.e., discontinuous or
partially
discontinuous lamination) to provide the light bonds. In alternative
implementations, the
lamination may be continuous. For example, films could be co-extruded so that
the films
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have a bond strength that provides for delamination prior to film failure to
provide similar
benefits to those described above. Thus, the described embodiments are to be
considered
in all respects only as illustrative and not restrictive. All changes that
come within the
meaning and range of equivalency of the claims are to be embraced within their
scope.
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