Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
METHODS AND APPARATUS FOR PRODUCING SCORED MEDIUMS,
AND ARTICLES AND COMPOSITIONS RESULTING THERE FROM
BACKGROUND OF THE INVENTION
Corrugated board, also known as corrugated cardboard or colloquially as
cardboard, represented a significant advancement in the container arts. Single
wall corrugated board comprised a fluted paper medium bonded to and separating
two flexible liners of paper to create an engineered article having
exceptional
stiffness or resistance to deflection in the in the strong axis or flute
direction (i.e.,
parallel to the flutes) due to beam strength induced by the flutes, and good
stiffness in the weak axis or orthogonal direction thereto (i.e.,
perpendicular to the
flutes) due to one of the sheets resisting deflection through tensioned
resistance
between flute peaks and an opposing sheet resisting deflection through
compressive resistance there between.
To increase resistance to deflection and/or increase flexural stiffness of
single
and/or multiple wall corrugated board in general, and particularly in the weak
axis,
one may increase the basis weight of the liners and or fluted medium; increase
the
flute pitch; modify the pulp characteristics of the material used for the
liners and/or
fluted medium; control fiber orientation in the materials used for the liners
and/or
fluted medium; and/or augment the liners and/or flute medium by coating or
other
structural modifications. Additionally, increased resistance to deflection
and/or
increased flexural stiffness can be achieved by creating multiple wall
corrugated
boards, e.g., double and triple wall boards, by layering single faced
corrugated
board.
A common theme to the aforementioned solutions for increasing resistance
to deflection and/or increasing flexural stiffness of a single wall corrugated
board
is the requirement for modifying the constitution of the paper itself, i.e.,
material
properties such as basis weight, fiber orientation or material composition, or
modifying the flute configuration, i.e., flute frequency (pitch) or amplitude
(caliper).
In each instance a change in the material constitution or article design must
be
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made prior to formation of the corrugated board article, which may not be
suitable
for other applications. As a consequence, more stock materials must be stored
for
disparate purposes, production lines must be changed for different runs, etc.
Heretofore, corrugated board liners have been characterized as generally
planar, the result of which has been single wall corrugate board having a
generally
smooth surface on both major sides thereof. If increased flexural stiffness
was
desired, a plethora of pre- and post formation manipulations have been
employed:
from the simple such as creating multiple faced corrugated board (e.g., double
or
triple faced board) to the more complex such as laminating multiple single
wall
corrugated board during article converting processes.
SUMMARY OF THE INVENTION
Accordingly, embodiments of the present invention are directed to a board
comprising a first cellulose medium that includes two major surfaces
exhibiting a
longitudinal direction; and a second cellulose medium that includes two major
surfaces exhibiting a longitudinal direction, wherein the first and the second
cellulose mediums are attached to each other by an adhesive, characterized in
that the first cellulose medium comprises a plurality of continuous plastic
scores
having a major axis direction aligned with a beam strength direction of the
first
cellulose medium that is aligned with the longitudinal direction of the first
cellulose
medium; and the second cellulose medium comprises a plurality of continuous
flutes having a major axis direction aligned with a beam strength direction of
the
second cellulose medium, wherein the major axis direction of the first
cellulose
medium's scores is not parallel with the major axis direction of the second
cellulose medium's flutes.
BRIEF DESCRIPTION OF THE DRAWINGS
Aspects and many of the attendant advantages of the claims will become
more readily appreciated as the same become better understood by reference to
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Date Recue/Date Received 2022-03-18
the following detailed description, when taken in conjunction with the
accompanying drawings, wherein:
FIG. 1 is a diagram of a portion of resultant corrugated paper product that
includes a liner portions and a fluted portion with incongruent major axes
according to the subject matter disclosed herein; and
FIGS. 2A-2C show various embodiments of scores with respect to different
cross-sectional score profiles according to various embodiments of the subject
matter disclosed herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The subject matter described herein is directed to methods and apparatus
for making scored mediums, particularly but not exclusively for use in the
corrugated board arts, and articles of manufacture and compositions made there
with and made there by. FIG. 1 is a diagram of a portion of resultant
corrugated
paper product 100 that includes a liner medium 106 and a fluted medium 105
with
incongruent major axes according to the subject matter disclosed herein. When
at
least one scored medium 106 is used in a layered or laminated article 100, and
particularly when selectively used as a liner member and/or fluted member in a
corrugated board, whether as part of a corrugated board article of manufacture
or
a laminate with at least one other member, the article will possess mechanical
qualities superior to those that would otherwise exist if a non-scored medium
was/were used. To achieve these desired qualities, a major axis 115 of the
scores
135 formed in the scored medium 106 runs askew (incongruent), and preferably
perpendicular, to the direction 120 of beam strength in any article or article
intermediate to which the scored medium is to be associated (e.g. the major
axis
120 of the fluted medium 105 in FIG. 1).
For example, the direction of beam strength of a fluted member 105 is
parallel to its major axis 120 (the flute direction, i.e., the direction of a
continuous
peak 140 or valley 141). Similarly, the direction of beam strength of a scored
liner
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106 at a score is parallel to the score's major axis 115 (the score direction,
i.e., the
direction of a continuous peak or valley).
As a result of integration and/or substitution of scored mediums according to
these various embodiments with or in, for example, corrugated boards,
performance characteristics associated with conventionally derived corrugated
boards can be achieved even while using lower basis weight materials
(liners/fluted members), lower quality materials (higher recycled content),
and/or
decreased caliper. Moreover, in selected embodiments, preferential failure of
embodiments serve to localize deformations, thereby increasing overall end
article
performance due to uniformity and predictability of converting actions and in-
use
load distributions.
As used herein, a "medium" refers to a flexible, yet deformable, substantially
planar material, which includes two major surfaces and a longitudinal
direction, of
which a "sheet" is a subset thereof. The medium may be formed from cellulose,
plastic(s) or combination thereof, and may be highly elongate in nature, e.g.,
a web.
The medium is preferably intended for, but is not restricted to, use as an
element,
member or component in corrugated boards, laminated boards and combinations
thereof.
The term "corrugated board" as used herein refers to single face, single wall
or multiple wall engineered boards having at least one fluted element or
component
(an "element or component" is also referred to herein as a "member"), and at
least
one liner member attached thereto (the combination of a fluted member and a
liner
member is conventionally referred to as a single face corrugated board).
The term "laminated board" as used herein refers to engineered boards
having at least two sheets at least partially adhered to each other in
overlapping
fashion. Laminated boards may be used alone or as a member in a corrugated
board.
The term "score" as used in the singular sense herein refers to a type of
surface feature characterized as an elongate, non-penetrating deformation
formed
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in a medium wherein the deformation may be plastic, non-plastic or a
combination
thereof. Examples of plastic deformation include embossing, pressing and
environmental modification (e.g., an elevated moisture and temperature
environment); examples of non-plastic deformation include conventional roll
forming (e.g., conventional scoring), bending, and folding. For many of the
articles of manufacture and compositions comprising a scored medium that are
disclosed herein, plastic deformation during score formation is preferred.
Referring back to FIG. 1, the non-penetrating deformation or score 135 is
established in the medium 106 after its initial formation, i.e., not as part
of the
medium's innate formation process such as would be the case during an
extrusion
formation process. As will be discussed in greater detail below, establishing
scores 135 after creation of the medium 106 provides exceptional economies and
flexibility in creating articles of manufacture and compositions comprising a
scored
medium such as a liner member for corrugated boards.
Once established, the score 135 is preferably permanent, meaning that
evidence of the score 135 will remain at least until, and preferably after,
integration with other article elements ¨ if the scored medium 106 is a liner
member, then substantially all scores 135 exist after its attachment to a
fluted
member 105. Additionally, each score 135 defines a major axis 115
corresponding to its primary direction of elongation, and may define a greater
than
nominal minor axis.
Scored mediums 106 comprise a plurality of spaced apart scores 135
wherein the major axes 115 of at least some of the scores are preferably
characterized as generally parallel to one another.
Depending upon the embodiment, each score 135 will have certain score
attributes, namely, a cross sectional profile, a directional orientation
relative to the
medium, and a major axis quality, which includes a continuity quality. Each of
these attributes both singularly and in combination affect the mechanical
qualities
of the medium 106 and/or articles and compositions(such as board 100) that
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include the medium. As will be described in more detail below, certain
attributes
may have substantial effects with regard to the resulting articles and
compositions.
FIGS. 2A-2C show various embodiments of scores with respect to different
cross sectional score profiles according to various embodiments of the subject
matter disclosed herein. Three principal types of score cross-sectional
profiles exist,
namely, rectilinear (e.g., "V" or "1_1") (FIG. 2A), curvilinear (e.g.,
semicircular)(FIG.
2B) and hybrid (e.g., "U")(FIG. 20). Each of these profiles in turn has a
directional
orientation relative to the medium, i.e., positive (a protrusion or land) or
negative (a
recess or groove) when viewed from one side thereof. Because a land on one
side of the medium usually constitutes a groove on the other, the nomenclature
is
inherently indefinite unless only one side of the medium is being considered.
Therefore, when describing the directional orientation of score profiles, it
is
necessary to maintain reference to a single side of the medium.
The major axis 115 quality of a score considers the score's characteristics
along its run length. Such characteristics include planar orientation, i.e.,
directional orientation relative to the medium's major axis (e.g., parallel or
non-
parallel), and/or deviation(s) from the score's nominal major axis (e.g.,
sinusoidal,
square or sawtooth geometry); and consistency or variability of score depth
along
its run length relative to the adjacent surface of the un-scored medium. The
score
depth may have constant or variable caliper and may include no depth, thereby
creating non-scored portions or a segmented score. If in segmented form, the
major axis quality of this characteristic may be characterized as patterned or
random in segment length and/or pitch. As a corollary, a score need not extend
a
majority of a medium, although in many embodiment applications it does.
Depending upon the embodiment, a plurality of scores will have certain group
qualities or attributes that may be characterized in certain ways. With
respect to
score attributes, two adjacent scores having identical score attributes will
be
considered homogeneous scores; a plurality of adjacent scores having identical
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score attributes will be considered a homogeneous group of scores. The
converse
is then also true: two adjacent scores having non-identical score attributes
will be
considered heterogeneous scores; a plurality of adjacent scores having non-
identical score attributes will be considered a heterogeneous group of scores
(although a subset of scores within the plurality may have identical score
attributes
and therefore the subset would be considered homogeneous scores).
With respect to score pitch, a plurality of adjacent scores having identical
lateral spacing, preferably over each score's run length, will be considered
to have
a constant score pitch while a plurality of adjacent scores having non-
identical
lateral spacing will be considered to have a variable score pitch (although a
subset
of scores within such plurality may have constant spacing and therefore the
subset
would have a constant score pitch).
The foregoing definitions presumed that the scores within a plurality were
parallel to one another. However, such a geometric relationship is not
necessary in
order to fall within the scope of the subject matter disclosed herein. In such
instances, the relative score pitch is variable along the run length of
adjacent
score, and is referenced herein as a skewed score pitch. Again, the degree of
relative convergence/divergence over a run length may be constant between
adjacent scores or may be variable.
Corrugated article embodiments (such as shown in FIG. 1) comprise at
least one scored member 106 in combination with its counterpart member 105. In
other words, if the scored member 106 is a liner member, then the counterpart
member 105 is a fluted member. If the scored member is a fluted member, then
the counterpart member is a liner member. In this basic form, the article is
considered a scored single face corrugated board. When an additional liner
member is attached to the fluted member, the resulting article is considered a
scored single wall corrugated board. Corrugated article embodiments also
include single wall corrugated board comprising two scored liner members, with
or
without incorporation of a scored fluted member. By extension, double wall
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corrugated boards can comprise one, two or three scored liner members (with or
without incorporation of one or two scored fluted members), and triple wall
corrugated board can comprise one, two, three or four scored liner members
(with
or without incorporation of one, two or three scored fluted members).
Turning first to scored liner member embodiments, for maximum
performance (e.g., stiffness) the overall score run direction/axes 115 of a
scored
liner member 106 is established perpendicular to the fluted member axis 120,
thereby creating beam strength in the liner member 106 that is parallel to the
fluted
member's weak axis. While the directional orientation of liner member scores
135
can be positive and/or negative in reference to the exposed or outer (non-
fluted)
side of a single face corrugated board, the scores are preferably
characterized as
negative. In this manner, positive surface features extend towards and into
the
peaks 140 of the fluted member 105. Since the exposed or outer side of the
liner
member only has negative surface features, the caliper of corrugated boards
comprising such scored liner member(s) remains unaffected by the inclusion
thereof. Moreover, when viewed from the inner surface of the liner member, the
positive surface features presenting to the peaks 140 of the fluted member 105
function to mechanically interact therewith, which when combined with the use
of
adhesive increases the strength of the bond there between.
Alternatively, if the directional orientation of the scores 135 in the liner
member 106 are reversed, a glue pocket may be created at the interface between
the flute peak of the fluted member and the negative features of the liner
member's
inner surface. If glue is applied to the liner member 106 as opposed to the
flute
peaks 140, the inner surface negative features may receive additional glue and
thereby enhanced structural properties after its cure. In addition, because
the
scored liner member 106 in such embodiments will have positive surface
features
present on the outer surface thereof, the coefficient of friction for such
liner member
will be altered, which may have functional benefits in certain applications.
Finally, a scored liner member 106 can have a heterogeneous mix of score
orientations, thereby potentially realizing benefits of both orientations
described
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above. In such embodiments, at least some of the scores 135 have a directional
orientation substantially opposite to that of at least some other scores. The
mix
may present a pseudo-sinusoidal pattern (i.e., adjacent scores have opposite
orientations), grouped patterns of orientations and/or random orientations.
Corrugated boards comprising a scored medium also include embodiments
wherein the fluted member comprises a plurality of scores. As was the case
with
scored liner member embodiments, the overall score run direction/axes is
established perpendicular to the fluted member major axis, thereby creating
beam
strength in the fluted member that is parallel to the fluted member's weak
axis. It
should be appreciated that the minor axis width of such scores as well as
their
pitch will likely be larger and greater than of those for liner members.
Although
this preferred difference results from optimizing the formation of the fluted
member, it is not necessary to the functioning of various embodiments.
Because scored liner members 106 may be used for enhancing structural
plubeiLIUS Ur bil iglu fa ue ourrugated boards 100, many embodiments will
comprise
a liner member 106 having a plurality of constant pitch, homogeneous linear
scores
135 formed therein, wherein several factors are considered when determining
the
nature of the scored liner member 106, namely, score amplitude (i.e., relief
or
caliper), score pitch and score displacement. Preferably, these factors are
also
considered in light of the nature of the fluted member 105 that forms part of
the
ultimate corrugated board 100.
The parameters of score amplitude and pitch for any liner member 106
depend upon a variety factors, which are highly application dependent.
Nevertheless, amplitude and pitch considerations include, but are not limited
to, the
amount of lateral take-up, the liner member basis weight or caliper, and the
corrugating environment if the scored liner member forms one part of a single
face
corrugated board or similar board.
In addition to score amplitude and pitch, score displacement relative to the
major axis 120 of the flutes formed in the fluted member 105 is another
important
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factor when discussing corrugated boards comprising at least one scored liner
106. Score displacement considers the relative angle between the predominant
score major axis 115 or run direction of the scored liner member 106 and the
flute
direction 120 (or, in the non- corrugated arts, the predominant score major
axis of
a second scored sheet). Generally speaking, the score displacement will be 90
relative to the flute direction 120 for maximum resistance to weak axis
bending of
the fluted member. However, there may be instances wherein predictable
localization of stresses is more desired than maximum stiffness and resistance
to
shear. Thus, score displacement need not be 900 in order to be within the
scope
herein.
It should be again understood that the scoring methods and resulting liner
members disclosed herein can be used when forming any corrugated board, and
need not nor should be limited to "first face" applications to form single
face
corrugated boards. Consequently, conventionally formed single face corrugated
board can be used in conjunction with a scored second liner member to form a
single wall corrugated board. Additionally, single face corrugated board
comprising
a scored liner member can be combined with another scored liner member to form
a single wall corrugated board with two scored liner members. Moreover, a
scored
fluted member can be used in conjunction with any of the foregoing
combinations.
Thus, the scope herein extends to any medium making up part of a corrugated
board.
The term "flutes" as used herein refers to a manipulation (as opposed to a
modification) of a medium to transform it from a generally planar geometry to
a
generally sinusoidal geometry, which may have constant pitch, i.e., period,
and
conventionally forms one part of a single face corrugated board.
As noted previously, scored mediums need not be used as a liner member
in conjunction with a fluted member, whether scored or not ¨ at least one
scored
medium can be associated with one or a plurality of non-scored members.
However, optimal performance can be achieved when pairs of orthogonally
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oriented scored members are used in a laminated article of manufacture, or
when
a plurality of scored members are so used and the net score major axis is
minimal
or zero (for example, a 3 x 1200 displacement; a 5 x 72 displacement; a 6 x
60
displacement; etc.). Although a corrugated fluted member is not used, many, if
not most, of the same characterizations apply as did with respect to
embodiments
comprising a corrugated fluted member. Moreover, in many respects, a scored
member can be considered to have analogous performance qualities to that of a
corrugated fluted member.
By extension, certain articles of manufacture incorporating the embodiments
discussed above comprise corrugated board having (a) laminated face(s)
comprising at least one scored liner member in combination with one of a non-
scored liner member or another scored liner member. These hybrid corrugated
boards therefore have one or more liner members having enhanced caliper, and
preferably, enhanced stiffness due to the presence of at least one scored
liner
member.
While a web of scored medium may be created at the time of its
manufacture, enhanced benefit can be realized through on-site formation of
scored
mediums from generic webs of the medium to meet the requirements of any given
production run; by so doing, storage and setup of dedicated webs of scored
mediums are thereby eliminated. In addition, roll density (run length) is
greater for
non-scored mediums than for scored mediums. Moreover, unintentional crushing
of the surface features that characterize the scores is avoided if it is
created just
prior to incorporation with, for example, a fluted member.
Another advantage to concurrent score formation and corrugation occurs
due to the environment in which the single face corrugating process takes
place.
To properly condition the medium that ultimately forms the fluted member, the
medium is exposed to elevated temperature and humidity in this environment.
These conditions permit the medium to more easily conform to the corrugating
rollers and retain the sinusoidal shape after release therefrom. Similarly, by
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exposing the medium that ultimately forms the single face liner member to such
an
environment prior to scoring, the medium will be more compliant and the
impressed scores will better retain their shape during subsequent handling and
processing. Similarly, creation of scores in the material that ultimately
becomes the
fluted member will be concurrent with the corrugation process, again
benefiting
from the elevated temperature and humidity environment in this preferred
environment.
The container arts frequently manipulate single, double and triple wall
corrugated board into variously shaped containers. This manipulation requires
converting the planar corrugated board (i.e., blank) into multiple sided
containers or
boxes. The converting process relies upon, inter alia, establishing scores
that
serve to localize a crease that results when forming container edges/corners
through bending or folding of the corrugated board. The resulting crease is
the
manifestation of an intentional failure of the corrugated board: compression
of the
putative inner liner of the container or box is biased at or towards the
score. As
those persons skilled in the art appreciate, there is balance between creating
a
sufficiently effective score (high relief) and not breaching or penetrating
the scored
liner. Too little compression by a scoring wheel and the score's effectiveness
is
marginalized; too much compression by the scoring wheel and the liner can be
penetrated, thereby materially weakening the resulting edge or corner joint.
Because integrated scored liner members enhance the stiffness of a
corrugated board article by creating beam strength in the scored liner
preferably in
opposition to the weak axis of the board, it follows that mechanically
destroying the
structure associated with the induced beam strength will localize stresses
imparted
upon the board at or proximate to such locations.
In many corrugated board embodiments, the predominant major axes of the
scores (run length) in at least one scored liner member are oriented
perpendicular
to the fluted member major axis, as has been previously described. Because
blank
scoring predominately occurs parallel to the fluted member major axis (which
is
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perpendicular to its weak axis), such blank scores will necessary run
perpendicular
to the liner member score run lengths (major axes). Consequently, any re-
scoring
of the scored liner member (particularly, but not exclusively, on the positive
surface
feature side of the liner member) will compromise the integrity of the liner
member
scores, thereby directing stress induced failures (such as resulting from
compressive converting actions) to the locations where the re-scoring has
occurred. In this manner and particularly with respect to the re-scoring of
positive
feature side scores, it is only necessary to defeat the initial scoring rather
than to
mechanically deform the base liner member and/or fluted member through
relatively high compression scoring in order to facilitate formation of a
corrugated
board fold/corner. An additional advantage of this ability is realized through
the use
of lower basis weight inner liners: since it is only necessary to defeat the
scoring
that results in beam formation, which itself was a result of material
deformation, less
consideration need be given to concerns regarding over- compression and medium
penetration.
As touched upon above and to enhance the likelihood of failure in such
instances and minimize unintended destruction of the scored liner in one
series of
embodiments, a scored liner of a blank, which forms an inner surface of a
corner or
fold, preferably comprises positive surface feature scores on the exposed side
of a
corrugated board blank inner surface (the side opposite the fluted member). By
so
doing, when such inner liner member is subjected to compressive force through
re-
scoring, the previous score-induced beams are intentionally destroyed,
beneficially
with minimal mechanical consequences to the virgin (non-previously scored)
portions of the inner liner member. While the foregoing embodiments are
presently
preferred, in another series of embodiments the scored inner liner member
presents
its positive surface features to the fluted member side of the corrugated
board
blank. While greater scoring pressure is needed in such embodiments, certain
advantages over the first series embodiments exist: In both series of
embodiments,
the subsequent re-scoring biases compressive failure of the inner liner member
towards the outer liner member, thereby increasing the density of material
within
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the fold/joint structure during the bending process, however, in the second
series of
embodiments, the reliability of such directional failure is considered more
robust.
It should be noted that blank scoring may be optional during the blank
converting process: in situations wherein the scored liner member of a
corrugated
board (for simplification, a single wall board is presumed) forms an inner
surface of
the converted form, simple bending of the board induces a compression load to
all
scores at the common axis of the hinge moment, which results in the scores
generally uniformly failing at their mid points between flute peaks; these
points are
the most susceptible to compression failure. The resulting uniform "failure"
of the
scores at this common location along a fluted member, which corresponds to a
flute
valley, permits the inner liner member to displace into the valley, thereby
creating a
clean bend or fold or edge. Moreover, because the valley corresponds to a peak
on the opposite side of the corrugated board, there is only minimal or nominal
tension induced into the outer liner member at the bend/fold/edge location. As
a
consequence of this optimal arrangement, the inner surface of the
bend/fold/edge
remains cleans and consistent along the length of the flute valley while the
outer
surface thereof retains most if not all original structural integrity. This
optimization
also permits a materially higher article reuse value: the hinge created by
this
arrangement is much less susceptible to material degradation over many cycles.
And while an inner side scored liner member is preferred, similar
functionality can
also be achieved through use of an outer side scored liner member, although
the
results may not be as consistent or optimized.
For purposes of this patent, the terms "area", "boundary", "part", "portion",
"surface", "zone", and their synonyms, equivalents and plural forms, as may be
used herein and by way of example, are intended to provide descriptive
references or landmarks with respect to the article and/or process being
described. These and similar or equivalent terms are not intended, nor should
be
inferred, to delimit or define per se elements of the referenced article
and/or
process, unless specifically stated as such or facially clear from the several
drawings and/or the context in which the term(s) is/are used.
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