U.S. patent application number 13/171632 was filed with the patent office on 2013-01-03 for flexible multi-panel sterilization assembly.
Invention is credited to Laureen C. Clark, Steven Friderich, Melissa Robyn Gaynor, Alice Susan Gordon, Brian Lowell Gustin, Shawn Eric Jenkins, Corinna Schwarz, Tara Denise Smith.
Application Number | 20130001283 13/171632 |
Document ID | / |
Family ID | 47389546 |
Filed Date | 2013-01-03 |
United States Patent
Application |
20130001283 |
Kind Code |
A1 |
Friderich; Steven ; et
al. |
January 3, 2013 |
Flexible Multi-Panel Sterilization Assembly
Abstract
A multi-panel sterilization assembly that includes a barrier
panel formed of a permeable material, a fold protection panel, and
at least one panel attachment means and which further includes at
least one reinforcement element.
Inventors: |
Friderich; Steven; (Roswell,
GA) ; Gordon; Alice Susan; (Roswell, GA) ;
Gaynor; Melissa Robyn; (Roswell, GA) ; Clark; Laureen
C.; (Johns Creek, GA) ; Gustin; Brian Lowell;
(Roswell, GA) ; Jenkins; Shawn Eric; (Duluth,
GA) ; Schwarz; Corinna; (Roswell, GA) ; Smith;
Tara Denise; (Marietta, GA) |
Family ID: |
47389546 |
Appl. No.: |
13/171632 |
Filed: |
June 29, 2011 |
Current U.S.
Class: |
229/87.01 |
Current CPC
Class: |
B65D 65/06 20130101;
A61L 2202/24 20130101; A61L 2202/181 20130101; A61B 50/33 20160201;
A61L 2/26 20130101; A61B 2050/3007 20160201; B32B 2262/0253
20130101; B32B 2439/80 20130101; B32B 5/26 20130101 |
Class at
Publication: |
229/87.01 |
International
Class: |
B65D 65/08 20060101
B65D065/08 |
Claims
1. A disposable flexible multi-panel sterilization assembly
comprising: a barrier panel comprising a permeable sheet material
having barrier properties, the barrier panel including: a first
surface and a second opposing surface, a first end generally
defining a pre-determined fold line, a second end opposite the
first end, a first edge that is generally perpendicular to the
pre-determined fold line, a second edge that is generally opposite
the pre-determined fold line, and a third edge that is generally
perpendicular to the pre-determined fold line, the barrier panel
having a width that is the distance from the first edge to the
third edge and a length that is the distance from the first end to
the second end, the barrier panel having a midpoint along the
length and extending between the first edge and the third edge to
generally delineate the barrier panel into a content receiving
region extending from the pre-determined fold line to the midpoint
and a content covering region extending from the midpoint to the
second edge; a panel attachment means between the pre-determined
fold line and the midpoint of the barrier panel at or near the
first edge or the third edge; the panel attachment means being
joined to the barrier panel at a pre-determined position to
identify the barrier panel's content receiving region and further
to join the barrier panel's first edge and third edge to each other
or to a portion of the content covering region after the barrier
panel has been folded at or near its midpoint such that its second
end is brought near its first end; and a fold protection panel in
juxtaposed communication with the barrier panel, the fold
protection panel comprising a permeable sheet material, the fold
protection panel including: a proximal end generally adjacent the
pre-determined fold line, a distal end generally opposite the
proximal end; and at least a first edge and a second edge extending
from the proximal end to the distal end, the fold protection panel
having a width that is the distance from the first edge to the
second edge and a length that is the distance from the proximal end
to the distal end, such that, after the barrier panel has been
folded at or near the barrier panel's midpoint so the barrier
panel's second end is brought near its first end and its first and
third edges are joined to each other or to its content covering
region to form a package, the fold protection panel is configured
to fold at or near the pre-determined fold line to cover at least
the first edge and the third edge of the folded barrier panel; and
at least one reinforcement element in the content receiving region
that defines an area for receiving content to be sterilized, such
reinforcement elements including a polyethylene film.
2. The sterilization assembly of claim 1, wherein the polyethylene
film comprises high density polyethylene.
3. The sterilization assembly of claim 2, wherein the polyethylene
film further comprises low density polyethylene.
4. The sterilization assembly of claim 2, wherein the polyethylene
film further comprises a linear low density polyethylene.
5. The sterilization assembly of claim 1, wherein the sterilization
assembly demonstrates a reduction in the formation of pinholes over
an alternate permeable nonwoven barrier material having a basis
weight within about 10% of the basis weight of the barrier panel
utilized in the sterilization assembly.
6. The sterilization assembly of claim 1, wherein the sterilization
assembly demonstrates a reduction in the formation of pinholes over
an alternate permeable nonwoven barrier material having a basis
weight within about 20% of the basis weight of the barrier panel
utilized in the sterilization assembly.
7. The sterilization assembly of claim 1, wherein the addition of
the at least one reinforcement element increases the basis weight
of the barrier material by less than about 50%.
8. The sterilization assembly of claim 1, wherein the addition of
the at least one reinforcement element increases the basis weight
of the barrier material by less than about 25%.
9. A disposable flexible multi-panel sterilization assembly
comprising: a barrier panel comprising a permeable sheet material
having barrier properties, the barrier panel including: a first
surface and a second opposing surface, a first end generally
defining a pre-determined fold line, a second end opposite the
first end, a first edge that is generally perpendicular to the
pre-determined fold line, a second edge that is generally opposite
the pre-determined fold line, and a third edge that is generally
perpendicular to the pre-determined fold line, the barrier panel
having a width that is the distance from the first edge to the
third edge and a length that is the distance from the first end to
the second end, the barrier panel having a midpoint along the
length and extending between the first edge and the third edge to
generally delineate the barrier panel into a content receiving
region extending from the pre-determined fold line to the midpoint
and a content covering region extending from the midpoint to the
second edge; a panel attachment means between the pre-determined
fold line and the midpoint of the barrier panel at or near the
first edge or the third edge; the panel attachment means being
joined to the barrier panel at a pre-determined position to
identify the barrier panel's content receiving region and further
to join the barrier panel's first edge and third edge to each other
or to a portion of the content covering region after the barrier
panel has been folded at or near its midpoint such that its second
end is brought near its first end; and a fold protection panel in
juxtaposed communication with the barrier panel, the fold
protection panel comprising a permeable sheet material, the fold
protection panel including: a proximal end generally adjacent the
pre-determined fold line, a distal end generally opposite the
proximal end; and at least a first edge and a second edge extending
from the proximal end to the distal end, the fold protection panel
having a width that is the distance from the first edge to the
second edge and a length that is the distance from the proximal end
to the distal end, such that, after the barrier panel has been
folded at or near the barrier panel's midpoint so the barrier
panel's second end is brought near its first end and its first and
third edges are joined to each other or to its content covering
region to form a package, the fold protection panel is configured
to fold at or near the pre-determined fold line to cover at least
the first edge and the third edge of the folded barrier panel; at
least one reinforcement element in the content receiving region
that defines an area for receiving content to be sterilized, such
reinforcement elements including a polyethylene film comprising a
high density polyethylene; and wherein the sterilization assembly
demonstrates a reduction in the formation of pinholes over an
alternate permeable nonwoven barrier material having a basis weight
within about 20% of the basis weight of the barrier panel utilized
in the sterilization assembly.
10. The sterilization assembly of claim 9, wherein the polyethylene
film further comprises a low density polyethylene.
11. The sterilization assembly of claim 9, wherein the addition of
the at least one reinforcement element increases the basis weight
of the barrier material by less than about 25%.
12. The sterilization assembly of claim 9, wherein the polyethylene
film further comprises a linear low density polyethylene.
Description
[0001] This application claims the benefit of priority from U.S.
Utility application Ser. No. 12/850,697 filed on Aug. 5, 2010,
which claims the benefit of priority from U.S. Provisional
Application No. 61/231,796 filed on Aug. 6, 2009, the contents of
both applications being incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates in general to disposable wraps
used to contain content to be sterilized and store that content
aseptically until use.
BACKGROUND OF THE INVENTION
[0003] A variety of products such as gowns, sheets, drapes,
instruments, etc. which are required during surgery or other
aseptic procedures, are used on a daily basis in the normal
operation of hospitals, clinics and the like. Where such products
are not pre-packaged in a sterile state, it is necessary for the
hospital or clinic to sterilize them before use.
[0004] Due to the volume of such products used in hospitals and
clinics, it is often necessary to sterilize and store these
products for later use. Accordingly, there has been developed a
procedure where such products, after cleaning, laundering and the
like, are wrapped in sterilization fabric and then sterilized and
stored for subsequent use. Disposable sterilization fabric is
typically cut into predetermined rectangular shapes and sold as
sterilization wraps.
[0005] Conventional disposable sterilization wrap is a flat,
featureless sheet of material that may occasionally contain one or
more additional layers of material for strength or absorbency.
Generally speaking, large sheets of conventional disposable
sterilization wrap are typically used to create large expanses of
overlapping materials using one or two standard fold techniques.
Large amounts of materials and multiple folds are used to create a
tortuous path (e.g., at least two sharp turns in the same
direction) to inhibit passage of airborne bacteria.
[0006] There are many ways items conventionally wrapped or packaged
in sterilization wraps can be contaminated. Certain modes of wrap
failure such as knife cuts, abrasion and punctures are
well-recognized. There are other modes of failure that are as
common if not more common. These include pressure cuts and pressure
holes.
[0007] A pressure cut can appear as a knife cut, but upon closer
examination, the fibers around the very edge of the cut have been
welded or stuck together. The edge of the cut may feel hard to the
touch. This type of cut usually follows the perimeter or outline of
the bottom of the instrument tray. It may also occur on the top of
the instrument tray, if a number of trays have been stacked upon
one another. An example of a typical event that may generate a
pressure cut would be lifting the front end of a heavily weighted
tray (such as, for example, a twenty pound tray) so that all the
weight of the tray is resting on a back edge, and pulling it across
the storage shelf before lifting. This is similar to cutting the
wrap with scissors; the material is caught between two layers of
hard solid interfaces with a shearing action applied to the
material.
[0008] A pressure hole may appear to be a tiny opening where the
fibers around the very edge of the hole have been welded or stuck
together. This type of hole is usually found along the perimeter of
the bottom of an instrument tray. It may also occur on the top of
the instrument tray if a number of trays have been stacked upon it.
An example of a typical event that may generate a pressure hole
would be a tray being dropped (even a small distance) onto an edge
of a cart or storage shelf while being transported to different
areas of the hospital.
[0009] The use of large sheets of conventional disposable
sterilization wrap with standard fold techniques are also generally
thought to help protect against pressure cuts and pressure holes as
well as the more commonly recognized modes of failure.
[0010] Accordingly, there is an unmet need for an assembly or
system of sterilization wrap or fabric that reduces the occurrence
of pressure cuts, pressure holes and the like while still reducing
the amount of sterilization fabric needed for sterile processing of
an instrument tray.
BRIEF SUMMARY OF THE INVENTION
[0011] The problems described above are addressed by the present
invention which encompasses a disposable flexible multi-panel
sterilization assembly. The disposable flexible multi-panel
sterilization assembly includes a barrier panel composed of a
permeable sheet material having barrier properties, panel
attachment means for securing the barrier panel into a package; and
a fold protection panel. The barrier panel includes: a first
surface and a second opposing surface; a first end generally
defining a pre-determined fold line; a second end opposite the
first end; a first edge that is generally perpendicular to the
pre-determined fold line; a second edge that is generally opposite
the pre-determined fold line; and a third edge that is generally
perpendicular to the pre-determined fold line. Desirably, the
barrier panel may have a fourth edge that is located generally
opposite the pre-determined fold line such that the second edge and
the fourth edge form an apex or vertex. More desirably, the barrier
panel may have a fourth edge and a fifth edge to define a
non-square or non-rectangular shape such that, for example, the
fourth edge and a fifth edge generally converge toward the second
edge such that the second end of the barrier panel is narrower than
the first end of the barrier panel.
[0012] The barrier panel may have a width that is the distance from
the first edge to the third edge and a length that is the distance
from the first end to the second end. According to an aspect of the
invention, the barrier panel has a midpoint along the length which
spans or runs between the first edge and the third edge to
generally delineate the barrier panel into a content receiving
region extending from the pre-determined fold line to the midpoint
and a content covering region extending from the midpoint to the
second edge.
[0013] The multi-panel sterilization assembly includes a panel
attachment means located between the pre-determined fold line and
the midpoint of the barrier panel. The panel attachment means is
desirably at or near the first edge or the third edge of the
barrier panel. Desirably, the panel attachment means may be at or
near both the first edge and the third edge of the barrier panel
and may be used to attach the barrier panel to itself after the
barrier panel is folded around content to be sterilized to form a
package. In an aspect of the invention, the panel attachment means
may be located in close proximity to the first edge and the third
edge of the barrier panel and/or may extend from the first edge and
the third edge of the barrier panel. The panel attachment means may
be adhesive tape, double-sided adhesive tape, cleavable release
tapes, layered release tapes, cohesive materials, hook and loop
fastening systems, mechanical fastening systems including, but not
limited to, snaps, clips, magnets, catches, slots and tabs, and
combinations thereof. According to an aspect of the invention, the
panel attachment means is joined to the barrier panel at a
pre-determined position. This pre-determined position may be near
the pre-determined fold line. The panel attachment means may be
configured to identify the barrier panel's content receiving region
and further to join the barrier panel's first edge and third edge
to each other or to a portion of the content covering region after
the barrier panel has been folded at or near its midpoint such that
its second end is brought near its first end.
[0014] The multi-panel sterilization assembly further includes a
fold protection panel in juxtaposed communication with the barrier
panel. That is, the fold protection panel desirably extends from
the barrier panel. If the fold protection panel is a separate piece
of material, it is desirably immediately adjacent to the barrier
panel in side-by-side relationship. The fold protection panel
includes: a proximal end generally adjacent or adjoining the
pre-determined fold line; a distal end generally opposite the
proximal end; and at least a first edge and a second edge extending
from the proximal end to the distal end. According to the present
invention, the fold protection panel may have at least a third edge
located at or along its distal end. The fold protection panel may
be configured so it has barrier properties. For example, the fold
protection panel may be formed of the same material as the barrier
panel. As another example, the fold protection panel may be formed
of the same piece of material as the barrier panel.
[0015] In an aspect of the invention, the fold protection panel
desirably has a width that is the distance from the first edge to
the second edge and a length that is the distance from the proximal
end to the distal end, such that, after the barrier panel has been
folded at or near the barrier panel's midpoint, the barrier panel's
second end is brought near its first end and its first and third
edges are joined to each other or to its content covering region to
form a package, the fold protection panel is configured to fold at
or near the pre-determined fold line to cover at least the first
edge and the third edge of the folded barrier panel.
[0016] The sterilization assembly may further include at least one
pull tab. The pull tab may be unitary with the barrier panel or it
may be attached to the second end of the barrier panel. The pull
tab may be formed of the same material as the barrier panel or may
be formed of one or more different materials. The pull tab provides
a feature that allows a user to unwrap a sterilized article
aseptically. That is, a person unwrapping an article that is folded
in the flexible multi-panel sterilization assembly may use the pull
tab to avoid reaching over the sterile field generally presented
from unwrapping and spreading out the sterile content-contacting
surface of the barrier panel.
[0017] The sterilization assembly further includes one or more
discrete reinforcement elements. These elements are desirably in
the content receiving region that define an area for receiving
content to be sterilized. The reinforcement element(s) may include
one or more layers of materials selected from fibrous webs,
impermeable films, permeable or porous films, apertured films,
foams, foils and combinations thereof. In selected embodiments, the
reinforcement elements are formed from a polyethylene, including a
high density polyethylene, a low density polyethylene, a linear low
density polyethylene or a combination of any of these.
[0018] The sterilization assembly preferably demonstrates a
reduction in the formation of pinholes over an alternate permeable
nonwoven barrier material having a basis weight within about 10% of
the basis weight of the barrier panel utilized in the sterilization
assembly. The addition of at least one reinforcement element may,
in selected embodiments, increase the basis weight of the barrier
material by less than about 50%.
[0019] In an aspect of the invention, there is provided a
disposable flexible multi-panel sterilization assembly that
includes a barrier panel formed from a sheet of barrier material
(e.g., barrier fabric) having at least one panel edge. The barrier
panel is configured to be folded around content to be sterilized to
form a package. Barrier panel attachment means are located on a
portion of the barrier panel for securing one or more panel edges
of the barrier panel in a folded configuration around content to be
sterilized. The barrier panel attachment means are configured to
secure the one or more panel edges in a folded configuration with
substantially greater resistance to shear force than to peel force.
The multi-panel sterilization assembly further includes a fold
protection panel extending from the barrier panel. The fold
protection panel includes a proximal end generally adjacent the
barrier panel and a distal end generally opposite the proximal end
such that the distal end of the fold protection panel covers the
one or more panel edges of the barrier panel after the barrier
panel is in the folded configuration.
[0020] The barrier panel attachment means are used to attach the
barrier panel to itself after the barrier panel is folded around
content to be sterilized to form a package. The barrier panel
attachment means may be adhesive tape, double-sided adhesive tape,
cleavable release tapes, cohesive materials, hook and loop
fastening systems, mechanical fastening systems including, but not
limited to, snaps, clips, magnets, catches, slots and tabs, and
combinations thereof.
[0021] The multi-panel sterilization assembly may include at least
one pull tab at the second end of the barrier panel; a panel
attachment means between the pre-determined fold line and the
midpoint of the barrier panel and at or near the first edge or the
third edge; the panel attachment means being joined to the barrier
panel at a pre-determined position to identify the barrier panel's
content receiving region and further to join the barrier panel's
first edge and third edge to each other or to a portion of the
content covering region after the barrier panel has been folded at
or near its midpoint such that its second edge is brought near its
first end.
[0022] The multi-panel sterilization assembly further includes a
fold protection panel in juxtaposed communication with the barrier
panel. The fold protection panel includes: a proximal end generally
adjacent or adjoining the pre-determined fold line; a distal end
generally opposite the proximal end; and at least a first edge and
a second edge extending from the proximal end to the distal end,
the fold protection panel having a width that is the distance from
the first edge to the second edge and a length that is the distance
from the proximal end to the distal end, such that, after the
barrier panel has been folded at or near its midpoint so its second
end is brought near its first end and its first and third edges are
joined to each other or to its content covering region to form a
package, the fold protection panel is configured to fold at or near
the pre-determined fold line to cover at least the first edge and
the third edge of the folded barrier panel.
[0023] These and other features and advantages of the invention
will become more apparent to one skilled in the art from the
following description and claims when read in light of the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The present invention will be better understood by reading
the Detailed Description of the Invention with reference to the
accompanying drawing figures, in which like reference numerals
denote similar structure and refer to like elements throughout, and
in which:
[0025] FIG. 1 is an illustration of an exemplary disposable
flexible multi-panel sterilization assembly.
[0026] FIG. 2A is an illustration of an exemplary disposable
flexible multi-panel sterilization assembly.
[0027] FIG. 2B is an illustration of an exemplary disposable
flexible multi-panel sterilization assembly with an integral pull
tab.
[0028] FIG. 2C is an illustration highlighting a detail of the
exemplary disposable flexible multi-panel sterilization assembly of
FIG. 2B.
[0029] FIG. 3A is an illustration of an exemplary disposable
flexible multi-panel sterilization assembly.
[0030] FIG. 3B is an illustration showing the opposite side of the
exemplary disposable flexible multi-panel sterilization assembly of
FIG. 3A.
[0031] FIGS. 4A to 4E are illustrations of an exemplary sequence of
folding an exemplary disposable flexible multi-panel sterilization
assembly.
[0032] FIGS. 5A to 5D are illustrations of exemplary disposable
flexible multi-panel sterilization assemblies showing exemplary
reinforcing elements.
[0033] FIGS. 6A to 6B are illustrations of exemplary reinforcing
elements.
[0034] FIG. 7 is an illustration of an exploded or broken apart
perspective view of exemplary features of an exemplary disposable
flexible multi-panel sterilization assembly.
[0035] FIG. 8 is an illustration of an exploded or broken apart
cross-section view of exemplary features of an exemplary disposable
flexible multi-panel sterilization assembly.
[0036] FIG. 9 is an illustration is an article positioned on an
exemplary multi-panel sterilization assembly.
[0037] FIG. 10 is a photograph of a conventional hard metal wire
mesh sterilization tray.
[0038] FIG. 11 is a photograph of a conventional rough surface
floor mat.
[0039] FIG. 12 is a photograph of a conventional medical cart upon
which have been placed conventional sterilization trays.
DEFINITIONS
[0040] As used herein, the term disposable refers to a product that
is so inexpensive that it may economically be discarded after only
a single use. Products that are disposable are typically intended
for single use. The term single-use refers to a product that is
intended to be used for only once and is not intended to be
re-used, re-conditioned, restored or repaired after that use.
[0041] As used herein, the term sterilization assembly refers to a
flexible article composed of fabric(s) and/or flexible material(s)
that is wrapped around, folded around or otherwise encloses a
non-sterile article or non-sterile content prior to sterilization.
A sterilization assembly has multiple panels and/or sections
providing specific physical properties, functional characteristics
and/or structure that provide advantages for wrapping or folding,
handling, strength, sterilization, storage after sterilization,
and/or unwrapping or unfolding.
[0042] As used herein, the term nonwoven web refers to a web that
has a structure of individual fibers or filaments which are
interlaid, but not in an identifiable repeating manner. Nonwoven
webs have been, in the past, formed by a variety of processes known
to those skilled in the art such as, for example, meltblowing,
spunbonding and bonded carded web processes.
[0043] As used herein, the term spunbonded web refers to a web of
small diameter fibers and/or filaments which are formed by
extruding a molten thermoplastic material as filaments from a
plurality of fine, usually circular, capillaries in a spinnerette
with the diameter of the extruded filaments then being rapidly
reduced, for example, by non-eductive or eductive fluid-drawing or
other well-known spunbonding mechanisms.
[0044] As used herein, the term meltblown fibers means fibers
formed by extruding a molten thermoplastic material through a
plurality of fine, usually circular, die capillaries as molten
threads or filaments into a high-velocity gas (e.g. air) stream
which attenuates the filaments of molten thermoplastic material to
reduce their diameters, which may be to microfiber diameter.
Thereafter, the meltblown fibers are carried by the high-velocity
gas stream and are deposited on a collecting surface to form a web
of randomly disbursed meltblown fibers.
[0045] As used herein, the term barrier fabric refers to a fabric
having a useful level of resistance to penetration by liquid and/or
particulates. Generally speaking, resistance to liquid penetration
is measured by hydrostatic head tests, strike-through tests, water
spray penetration tests and the like.
[0046] As used herein, ultrasonic bonding means a process
performed, for example, by passing the fabric between a sonic horn
and anvil roll as illustrated in U.S. Pat. No. 4,374,888 to
Bornslaeger, the entire contents of which is incorporated herein by
reference.
[0047] As used herein point bonding means bonding one or more
layers of fabric at a plurality of discrete bond points. For
example, thermal point bonding generally involves passing a fabric
or web of fibers to be bonded between a heated roll assembly such
as, for example, a heated calender roll and an anvil roll. The
calender roll is usually patterned in some way so that the entire
fabric is not bonded across its entire surface, and the anvil roll
is usually smooth. As a result, various patterns for calender rolls
have been developed for functional and/or aesthetic reasons.
[0048] The term polyethylene (PE) is used to refer to a
thermoplastic polymer consisting of long chains produced by
combining the ingredient monomer ethylene (IUPAC name ethene). The
term high density polyethylene (HDPE) is used to refer to
polyethylene generally having a density in a range of about 0.935
to about 0.980 grams per cubic centimeter, while low density
polyethylene (LDPE) is used to refer to polyethylene generally
having a density in a range of about 0.910 to about. 0.935 grams
per cubic centimeter. The term linear low density polyethylene
(LLDPE) is meant to include polymers of ethylene and higher alpha
olefin comonomers such as C.sub.3-C.sub.12 and combinations
thereof, and that the main polymer chain is linear with less than
approximately 5 long chain branches per 1000 ethylene units.
DETAILED DESCRIPTION OF INVENTION
[0049] In describing the various embodiments of the present
invention, as illustrated in the figures and/or described herein,
specific terminology is employed for the sake of clarity. The
invention, however, is not intended to be limited to the specific
terminology so selected, and it is to be understood that each
specific element includes all technical equivalents that operate in
a similar manner to accomplish similar functions.
[0050] The present invention encompasses a disposable multi-panel
sterilization assembly which addresses the problems generally
described above. An exemplary multi-panel sterilization assembly
100 is illustrated in FIG. 1.
[0051] The multi-panel sterilization assembly includes a barrier
panel 102 composed of a permeable sheet material 104 having barrier
properties (e.g., a barrier fabric), panel attachment means 106 for
securing the barrier panel 102 into a package, and a fold
protection panel 108. Generally speaking, the barrier panel is the
portion of a multi-panel sterilization assembly that is formed from
a material that is sufficiently permeable to permit a sterilizing
gas to pass through it to effect sterilization and has barrier
properties sufficient maintain that content in an aseptic condition
after sterilization. A barrier panel should also be sufficiently
flexible or conformable to that it is configured to receive and
subsequently enfold or enclose content to be sterilized thereby
forming a package. Generally speaking, the barrier panel may be a
barrier fabric. The fold protection panel is the portion of a
multi-panel sterilization assembly that is formed from a material
covers and protects at least a portion of the folded edges of the
barrier panel. The fold protection panel is the last panel or part
of the multi-panel sterilization assembly that is folded or wrapped
around the package formed by the barrier panel around content to be
sterilized and the first part of the multi-panel sterilization
assembly that is unfolded or unwrapped.
[0052] The barrier panel includes: a first surface 110 and a second
opposing surface 112; a first end 114 generally adjacent or
adjoining a pre-determined fold line 116; a second end 118 opposite
the first end 114; a first edge 120 that is generally perpendicular
to the pre-determined fold line 116; a second edge 122 that is
generally opposite the pre-determined fold line 116; and a third
edge 124 that is generally perpendicular to the pre-determined fold
line 116. The pre-determined fold line is a line or region
generally defined by the first end 114 of the barrier panel.
Generally speaking, the predetermined fold line is offset from the
boundary or transition between the barrier panel and the fold
protection panel towards the center or midpoint of barrier panel
102. The pre-determined fold line 116 identifies the desired
location for placing the content to be sterilized at the first end
114 of the barrier panel 102. The offset serves to provide a
sufficient amount of barrier panel that the content to be
sterilized is fully surrounded by the barrier panel after folding
is complete. The pre-determined fold line 116 may be offset from
the boundary or transition by about 0.5 inch (.about.13 mm) to
about 2 inches (.about.51 mm). Desirably, the pre-determined fold
line is offset by about 1 inch (.about.25 mm). The pre-determined
fold line may be in the form of a seam (or seams) such as, for
example, a stitched seam, an ultrasonic bond seam, adhesive bond
seam, thermo-mechanical bond seam (e.g., a bar seal seam) or
combinations thereof, that results from joining layers or plies
together to form the barrier panel and the fold protection
panel--or the seam(s) may result from joining pieces together if
the barrier and fold protection panels are discrete pieces.
Alternatively and/or additionally, the predetermined fold line may
be identified by printing, or by an imprint such as a
thermo-mechanical bond line (e.g., bar seal bond line) or pattern
or other indicia, or identified by a crease or other suitable mark.
The pre-determined fold line may be an intermittent line or indicia
and it may be provided directly on the barrier panel or it may be
provided on one or reinforcement elements if such are present.
[0053] As noted above, an important feature of the predetermined
fold line 116 is that it helps delineate where the content to be
wrapped and ultimately sterilized should be placed. That is,
content to be wrapped and sterilized should be placed adjacent only
one side of the predetermined fold line. As discussed subsequently,
other features of the present invention signal to a user which side
of the pre-determined fold line is the appropriate side to place
content. Yet another feature of the predetermined fold line 116 is
that it helps defines a boundary, reference line or limit for the
user during the wrapping of content to be sterilized. That is,
during wrapping of content to be sterilized, as part of the barrier
panel is brought over the content to be sterilized, that part of
the barrier panel should not be extended substantially across or
beyond the predetermined fold line 116. In contrast to conventional
sterilization wrap systems where the content is placed at the
center of the sterilization barrier, the multi-panel sterilization
assembly required placement at the pre-determined fold line near
the boundary or edge of the barrier panel. This is initially
counterintuitive for users and is quite different from conventional
sterilization wrap systems.
[0054] While the barrier panel 102 of FIG. 1 is generally shown as
having a square shape, the barrier panel 102 may be rectangular or
may desirably have additional edges to define a non-square or
non-rectangular shape. Portions of the edges may be arcuate or may
otherwise be non-linear. Alternatively and/or additionally, the
first edge 120 and the third edge 124 may converge or diverge so
the edges are not parallel, thereby defining a barrier panel 102
having a trapezoidal shape. It is also contemplated that other
combinations of opposite edges may converge or diverge.
[0055] For example and referring to FIG. 2A, the barrier panel may
have a fourth edge 126 to define a non-square or non-rectangular
shape. In such an exemplary configuration, the two edges 122 and
126 are generally opposite the pre-determined fold line 116 such
that the second edge 122 and the fourth edge 126 form an apex or
vertex. Thus, the barrier panel 102 may have a first surface 110
and a second opposing surface 112; a first end 114 generally
defining a pre-determined fold line 116; a second end 118 opposite
the first end 114; a first edge 120 that is generally perpendicular
to the pre-determined fold line 116; a second edge 122 that is
generally opposite the pre-determined fold line 116; a third edge
124 that is generally perpendicular to the pre-determined fold
line; and a fourth edge 126 located between the second edge 122 and
the third edge 124.
[0056] Referring to FIGS. 3A and 3B, the barrier panel 102 may have
a fourth edge 126 and a fifth edge 128 to define a non-square or
non-rectangular shape such that, for example, the fourth edge 126
and a fifth edge 128 generally converge toward the second edge 226
such that the second end 118 of the barrier panel is narrower than
the first end 114 of the barrier panel. Thus, the barrier panel 102
may have a first surface 110 and a second opposing surface 112; a
first end 114 generally defining a pre-determined fold line 116; a
second end 118 opposite the first end 114; a first edge 120 that is
generally perpendicular to the pre-determined fold line; a second
edge 122 that is generally parallel to the pre-determined fold line
116; a third edge 124 that is generally perpendicular to the
pre-determined fold line 116; a fourth edge 126 located between the
second edge 122 and the third edge 124; and, a fifth edge 128
located between the first edge 120 and the second edge 122. The
barrier panel has a first width W1 that is the distance from the
first edge 120 to the third edge 124 in the first end 114 (e.g.,
preferably measured along the pre-determined fold line 116) and a
second width W2 that is the distance from the fourth edge 126 to
the fifth edge 128 (e.g., preferably measured between the locations
where the fourth edge 126 and the fifth edge 128 meet the second
edge 122. The barrier panel also has a length L that is the
distance from the first end 114 (from the pre-determined fold line
116) to the second end (e.g., at the second edge 122). The barrier
panel also has a midpoint M along the length L and extending
between the first edge 120 and the third edge 124 or, in some
embodiments, the fourth edge 126 and the fifth edge 128 to
generally delineate the barrier panel 102 into a content receiving
region 130 extending from the pre-determined fold line 116 to the
midpoint M and a content covering region 132 extending from the
midpoint M to the second edge 122. Of course, it is contemplated
that additional edges may be added or that edges may be curvilinear
or may include curvilinear portions.
[0057] Referring again to FIG. 1, the barrier panel 102 may have a
width W that is the distance from the first edge 120 to the third
edge 124 and a length L that is the distance from the first end 114
to the second end 118. According to an aspect of the invention, the
barrier panel has a midpoint M along the length L which spans or
runs between the first edge 120 and the third edge 124 to generally
delineate the barrier panel 102 into a content receiving region 130
extending from the pre-determined fold line 116 to the midpoint M
and a content covering region 132 extending from the midpoint M to
the second edge 124. Generally speaking the content receiving
region is the portion of the barrier panel onto which a tray or
other content to be sterilized is initially placed. Unlike
conventional sterilization wrap in which a tray or content to be
sterilized is placed in the central portion of the barrier material
that forms the sterilization wrap, the content receiving region is
between the first end and the midpoint of the barrier panel. This
asymmetric placement on the barrier panel is not intuitive. The
content covering region is the portion of the barrier panel that is
folded over the content after the content has been placed on the
content receiving region.
[0058] In an aspect of the invention, the barrier panel of the
various illustrated configurations may have a width of from about
12 inches (.about.30 cm) to about 50 inches (.about.127 cm).
Desirably, the barrier panel may have a width of from about 18
inches (.about.46 cm) to about 40 inches (.about.102 cm). Even more
desirably, the barrier panel may have a width of from about 20
inches (.about.51 cm) to about 30 inches (.about.76 cm). The
barrier panel may have a length of from about 7 inches (.about.18
cm) to about 50 inches (.about.127 cm). Desirably, the barrier
panel may have a length of from about 15 inches (.about.39 cm) to
about 40 inches (.about.102 cm). Even more desirably, the barrier
panel may have a length of from about 25 inches (.about.64 cm) to
about 30 inches (.about.76 cm).
[0059] According to an aspect of the invention, the surface area of
the content receiving region 130 may be from about 25 percent to
about 49 percent of the total surface area of the barrier panel
102. For example, the surface area of the content receiving region
130 may be from about 35 percent to about 45 percent of the total
surface area of the barrier panel 102. This is important because
the content covering portion of the barrier panel should be larger
to provide additional surface area to properly cover the
content.
[0060] The multi-panel sterilization assembly 100 includes a panel
attachment means 106 located on the first surface 110 between the
pre-determined fold line 116 and the midpoint M of the barrier
panel. The panel attachment means 106 is desirably at or near the
first edge 120 and/or or the third edge 124 of the barrier panel.
Although the panel attachment means 106 is illustrated at or near
both the first edge 120 and the third edge 124 of the barrier
panel, the panel attachment means 106 may be at or near only one of
these edges.
[0061] The panel attachment means 106 may be located at and extend
from the first edge 120 and the third edge 124 of the barrier panel
as generally illustrated in FIGS. 1 and 2A and 2B. Alternatively
and/or additionally, the panel attachment means 106 may be located
generally near the first edge and/or the third edge as illustrated
in FIG. 3A and FIG. 4A. The panel attachment means may be one large
element or a number of discrete elements. Exemplary panel
attachment means include, but are not limited to, adhesive tape,
double-sided adhesive tape, cleavable release tapes, layered
release tapes, cohesive materials, hook and loop fastening systems,
mechanical fastening systems including, but not limited to, snaps,
clips, magnets, catches, slots and tabs, and combinations thereof.
For example, the panel attachment means may be one or more lengths
of adhesive tape having at least an end or portion that is
stitched, ultrasonically bonded, thermo-mechanically bonded or
adhered or adhesively bonded to the barrier panel. Desirably, the
panel attachment means is a barrier panel attachment means that is
located on the barrier panel and is used to join one or more edges
of the barrier panel to itself. It has been found that barrier
panel attachment means may be a double sided tape having the same
or different levels of adhesive or tack strength of adhesive on
each side. Alternatively and/or additionally, the panel attachment
means may have a double sided tape structure in which the central
layer sandwiched by the adhesive is a splittable or separable
material such as a splittable paper, splittable laminate,
splittable foam, cleavable paper, cleavable release structure,
cleavable foam or other cleavable or separable laminate.
[0062] According to an aspect of the invention, the panel
attachment means 106 may be in the form of an adhesive fastening
tab or tape closure system such as the various types frequently
used on diapers, incontinent garments and similar products. An
exemplary tape closure system may be found at, for example, U.S.
Pat. No. 4,410,325 issued to Lare on Oct. 18, 1983; the contents of
which are incorporated by reference. This system utilizes an
adhesive fastening tab or tape closure system (referred to herein
as a tape) that is folded back on itself and which has a first end
or portion that is attached to the article (e.g., one part of a
garment). During use, the tape is unfolded to reveal an exposed
adhesive surface at least at a second end or portion of the tape
which is then adhered to a different part of the article (e.g., a
second part of the garment) to secure the two parts of the garment
in the desired configuration. Generally speaking, the first end of
the tape panel attachment means 106 would be secured at or near the
first edge 120 of the barrier panel and the second end of the tape
panel attachment means 106 would be folded back onto the first end.
An additional panel attachment means 106 may be secured at or near
the third edge 124 of the barrier panel in a similar manner. During
use, the tape panel attachment means 106 would be unfolded to
reveal an exposed adhesive surface or surfaces at least at the
second end of the panel attachment means 106. The exposed adhesive
surface(s) of the panel attachment means at first edge 120 and/or
third edge 124 of the barrier panel would be used to secure those
portions of the barrier panel to each other and/or to other
portions of the barrier panel after the barrier panel is folded
about content to be sterilized. In such a configuration, an
optional attachment zone 305 may be utilized. An exemplary optional
attachment zone 305 is indicated by broken lines in FIG. 3B and in
FIG. 4B. In embodiments that utilize adhesive or cohesive materials
for the panel attachment means, the attachment zone 305 may be an
applied film, a more securely bonded portion of a nonwoven fabric,
a separate piece of a material, a coating or the like that provides
a suitable surface for the adhesive to bond securely so folded
barrier panel does not pop open or release when it should not do
so. The attachment zone 305 may be configured to signal to a user
the appropriate location or locations to secure the panel
attachment means. In such configuration, the attachment zone 305
may be combined with or may incorporate indicia such as color,
texture, alphanumeric characters or the like to direct a user. More
importantly, the attachment zone 305 can be configured to provide a
suitable surface such that the force required to release the panel
attachment means 106 is carefully controlled to preserve aseptic
opening, avoid tearing or shredding of the barrier fabric, provide
a satisfactory level of resistance to sheer forces, and/or provide
a satisfactory or controlled level of resistance to peel
forces.
[0063] Another exemplary tape closure system may be found at, for
example, U.S. Pat. No. 4,585,450 issued to Rosch et al. on Apr. 29,
1986; the contents of which are incorporated by reference. This
system utilizes an adhesive fastening tab or tape closure system
(referred to herein as a tape) that includes a secondary tape
element and a primary tape element. The tape has a first end or
portion that is attached to the article (e.g., one portion of a
garment). The second end or portion contains the secondary tape
element and primary tape element. During use, an adhesive surface
of the primary tape element is exposed. The adhesive surface of the
primary tape element is then adhered to a different part of the
article (e.g., a second part of the garment) to secure the two
parts of the garment in the desired configuration. An adhesive bond
between the primary tape element and the secondary tape element has
less strength than the adhesive bond between the primary tape
element and the second part of the garment or article such that the
bond between the primary tape element and secondary tape element
may be reliably separated, repeatedly if necessary.
[0064] Generally speaking, the first end or a first side of a panel
attachment means 106 would be secured at or near the first edge 120
of the barrier panel and the second end or the second side of the
tape panel attachment means 106 would be folded back onto the first
end or otherwise covered by a release element. An additional panel
attachment means 106 may be secured at or near the third edge 124
of the barrier panel in a similar manner. During use, the primary
tape element of the panel attachment means 106 would be unfolded or
uncovered to reveal an exposed adhesive surface(s) at least at the
second end or second side of the panel attachment means 106. The
exposed adhesive surface(s) of the primary tape element of would be
used to join the first edge 120 and/or third edge 124 of the
barrier panel to each other or to other portions of the barrier
panel after the barrier panel is folded about content to be
sterilized. In such a configuration, the adhesive bond between the
primary tape element and the secondary tape element has less
strength than the adhesive bond between the primary tape element
and the portion of the barrier panel to which it is adhered such
that the bond between the primary tape element and secondary tape
element may be reliably separated, repeatedly if necessary. In some
respects, the primary tape element may function as an attachment
zone. That is, after the primary tape element is adhered to the
barrier panel to secure the barrier panel in a folded
configuration, the primary tape element may provide a suitable
surface such that the force required to overcome the adhesive bond
between the primary tape element and the secondary tape element is
carefully controlled to preserve aseptic opening, avoid tearing or
shredding of the barrier fabric, provide a satisfactory level of
resistance to sheer forces, and/or provide a satisfactory or
controlled level of resistance to peel forces. In another aspect,
the attachment zone 305 as describe previously or in the form of
the primary tape element may be used to allow a worker to re-open
the wrapped barrier panel prior to inspect contents prior to
sterilization and then re-attach the panel attachment means without
having to destroy the multi-panel sterilization assembly.
[0065] As another example, the panel attachment means may be a
length of fabric such as nonwoven fabric having an end or portion
that is stitched, ultrasonically bonded, thermo-mechanically bonded
or adhered or adhesively bonded to the barrier panel and having a
hook fastener from a hook and loop fastening system joined to the
other end. It is contemplated that the barrier fabric itself may
function as the loop component of a hook and loop fastening system
such as hook and loop fastenings systems available as VELCRO.RTM.
brand fastener products from Velcro Industries B.V. Other exemplary
hook systems may be used such as the hook system described in U.S.
Pat. No. 5,315,740 issued to Nestegard which relates to hooks
having small dimensions so they engage low cost loop materials such
as nonwoven webs.
[0066] It is contemplated that various elements or components of
the panel attachment means, may be integrally formed, such as by
molding, co-extrusion or the like, along with any associated
substrate layer. For example, the individual hook elements may be
integrally formed simultaneously with a hook base-layer by
coextruding the base layer and hook elements from substantially the
same polymer material.
[0067] According to an aspect of the invention, the panel
attachment means 106 is joined to the first surface 110 of the
barrier panel 102 at a pre-determined position 140 to identify or
distinguish the content receiving region 130 of the barrier panel
102 from the content covering region 132 as generally illustrated
in FIGS. 1 and 4A. The location of the panel attachment means 106
at the pre-determined position 140 also signals to a user an
optimum zone or region within the content receiving region 130 to
place content. This may be highlighted by indicia on the assembly
and/or instructions on the assembly or which accompany the assembly
and which may be posted in the workplace or displayed at a wrapping
station.
[0068] Referring to FIGS. 3A and 4A, the panel attachment means 106
is desirably a double sided tape having a length that is greater
than its width. For example, the panel attachment means may be a
double sided tape having a length that more than two times great
than its width. As another example, the panel attachment means may
be a double sided tape having a length that is four times great
than its width to eight times greater than its width. Alternatively
and/or additionally, the configuration of the panel attachment
means may be a series of tape squares arranged along or near the
first edge 120 and the third edge 124. The portion of the panel
attachment means 106 closest to the pre-determined fold line 116 is
desirably less than about 3 inches from the pre-determined fold
line 116. More desirably, the portion of the panel attachment means
106 closest to the pre-determined fold line 116 is desirably less
than about 2 inches from the pre-determined fold line 116. For
example, the portion of the panel attachment means 106 closest to
the pre-determined fold line 116 may be about 1 inch to about 1/2
inch from the pre-determined fold line 116.
[0069] Referring again to FIG. 1, the fold protection panel 108 of
the multi-panel sterilization assembly 100 is in juxtaposed
communication with the barrier panel 102. That is, the fold
protection panel 108 is in side-by-side relationship with or
adjoins the barrier panel 102. Generally speaking, the fold
protection panel 108 may be any suitable material but desirably is
formed of a permeable sheet material. According to the invention,
the fold protection panel includes a proximal end 142 generally
adjacent the pre-determined fold line 116; a distal end 144
generally opposite the proximal end 142; and at least a first edge
146 and a second edge 148 extending from the proximal end 142 to
the distal end 144. According to the present invention, the fold
protection panel may have additional edges. For example and with
reference to FIG. 2A, the fold protection panel may include at
least a third edge 150 located at or along its distal end 144. As
yet another example and referring now to FIG. 3A, the fold
protection panel may include at least a third edge 150 located at
or along its distal end 144 and a fourth edge 152 and a fifth edge
154.
[0070] Generally speaking, the fold protection panel may be a
lightweight material such as a lightweight laminate of spunbond
nonwoven material or a lightweight laminate of spunbond nonwoven
material and meltblown nonwoven material. As such, the fold
protection panel does not need to provide a higher level of barrier
properties like the material that forms the barrier panel. The fold
protection panel may be configured so it has barrier properties.
For example, the fold protection panel may be formed of the same
material as the barrier panel. It is contemplated that the fold
protection panel may be a single layer of spunbond nonwoven
material.
[0071] In an aspect of the invention, the fold protection panel
desirably has a width that is the distance from the first edge to
the second edge and a length that is the distance from the proximal
end to the distal end. The fold protection panel may have a width
of from about 12 inches (.about.30 cm) to about 50 inches
(.about.127 cm). Desirably, the fold protection panel may have a
width of from about 18 inches (.about.46 cm) to about 40 inches
(.about.102 cm). Even more desirably, the fold protection panel may
have a width of from about 20 inches (.about.51 cm) to about 30
inches (.about.76 cm). The fold protection panel may have a length
of from about 6 inches (.about.15 cm) to about 30 inches (.about.76
cm). Desirably, the fold protection panel may have a length of from
about 8 inches (.about.20 cm) to about 20 inches (.about.51 cm).
Even more desirably, the fold protection panel may have a length of
from about 12 inches (.about.30 cm) to about 15 inches (.about.38
cm).
[0072] During use, panel attachment means 106 are used to join the
barrier panel's first edge 120 and third edge 124 to a portion of
the content covering region 132 after the barrier panel 102 has
been folded at or near its midpoint M such that its second end 118
is brought near its first end 114. It is contemplated that in some
embodiments, the panel attachment means 106 may be used to join the
barrier panel's first edge 120 and third edge 124 to each
other.
[0073] According to an aspect of the invention, it is important
that the adhesive force or the engagement force at which the panel
attachment means join the respective edges of the barrier panel to
the content covering region of the barrier panel or to the edges
themselves should be sufficient to secure the barrier panel around
the content thereby forming a package that is robust and able to
withstand normal handling before as well as after
sterilization.
[0074] In exemplary arrangements, especially where there are
sufficiently high levels of engagement shear force provided by the
panel attachment means, the fastening engagement may provide a peel
force value of not less than a minimum of about 5 grams-force (gmf)
(about 0.012 lbs-force) between the panel attachment means and the
other portion of the barrier panel that it secures together.
[0075] The engagement force between the panel attachment means and
the other portion of the barrier panel that it secures together may
additionally provide a shear force value that is desirably greater
than about 5,000 gmf for a panel attachment means having dimensions
of about 4 by 1 inches (.about.102 by .about.25 mm).
[0076] It should be readily appreciated that the adhesive force or
the engagement force at which the panel attachment means join the
respective edges of the barrier panel to the content covering
region of the barrier panel or to the edges themselves should be
less than the peel strength of the bond that is used to join the
panel attachment means to the underlying barrier panel during
construction of the assembly. For example, the peel strength of the
bond (e.g., adhesive, mechanical, thermo-mechanical, ultrasonic,
etc.) that is used to join the panel attachment means to the
underlying barrier panel during construction should be much greater
than about 400 gmf for a panel attachment means having a dimension
of about 4 inches by 1 inch (about 10 cm by 2.5 cm). Desirably, the
peel strength of the bond that is used to join the panel attachment
means to the underlying barrier panel during construction should be
greater than about 400 gmf per square inch of the area of
engagement between the panel attachment means and the barrier. For
example, the bond strength may be more than 1000 gmf/square inch,
and may be more than 4,000 gmf/square inch.
[0077] Referring now to FIGS. 4A through 4E (and with additional
reference to FIG. 3A), there is illustrated an example of a
multi-panel sterilization assembly in an exemplary sequence of
folding. FIG. 9A illustrates a multi-panel sterilization assembly
100 composed of barrier panel 102 which cooperates with the fold
protection panel 108 and the panel attachment means 106 on the
first surface 110 so the barrier panel 102 can be folded around the
content 200 to form a package (such as the package 202 generally
illustrated in FIG. 4E). The barrier panel 102 is the portion of
the flexible multi-panel sterilization assembly 100 that contacts
and covers the content 202. The content 200 is placed in the
content receiving 130 which is generally defined by the panel
attachment means 106 on the first surface 110 of the barrier panel
102.
[0078] As generally illustrated in FIG. 4B, the second end 118 of
the barrier panel 102 is folded up at the midpoint M and brought to
the first end 114 so the content covering region 132 of the barrier
panel 102 extends over the content 200. As shown in FIG. 4B, the
width of the barrier panel at the second end 118 is less than the
width of the barrier panel at the first end 114. This is important
when the panel attachment means 106 are located directly on the
barrier panel as shown in FIGS. 3A and 4A (rather than extending
outward from the edges as illustrated in FIGS. 2A and 2B) because
it provides a configuration of the fourth edge 126 and the fifth
edge 128 that allows access to the panel attachment means 106 after
the second end 118 is brought up to the first end 114.
[0079] In some embodiments of the present invention, a pull tab or
tail 300 extends from the second end 118 so that the pull tab or
tail 300 is positioned to be accessible during the initial steps of
unfolding or unwrapping a wrapped package. The pull tab or tail 300
desirably extends from or is joined to the second end 118 of the
barrier panel on the second opposing surface 112 of the barrier
panel 102. Referring briefly to FIG. 2B, there is shown a
configuration in which the pull tab or tail 300 is unitary or
integral with the barrier panel. FIG. 2C illustrates that pull tab
or tail 300 on the second opposing surface 112 of the barrier panel
102. The distal end (i.e., the loose end) of the pull tab or tail
300 is desirably secured to the barrier panel with a light adhesive
or an adhesive tab or sticker such that the pull tab or tail 300
does not flop around during wrapping and is in an appropriate
position during unwrapping.
[0080] Referring now to FIG. 4C, that illustration shows that the
third edge 124 of the barrier panel 102 is folded over the second
end 118 (after the second end 118 is brought up to the first end
114). While not necessarily shown to scale, the third edge 124 of
the barrier panel 102 after folding does not extend very far toward
the middle of the assembly.
[0081] FIG. 4D illustrates that the first edge 120 of the barrier
panel 102 is folded over the second end 118. While not necessarily
shown to scale, the first edge 120 of the barrier panel 102 upon
folding does not extend very far toward the middle of the assembly.
Accordingly, it is evident that the third edge 124 and the first
edge 120 generally do not overlap.
[0082] Referring now to FIG. 4E, the fold protection panel 108 is
folded at the pre-determined fold line 116 bringing its distal end
144 over the second end 118 of the barrier panel. In some
embodiments, a portion of the material adjacent the first edge 120
and the third edge 124 may be visible. With this configuration, the
actual edges 120 and 124 of the barrier panel 102 are fully covered
so the edges themselves are less susceptible to being accidently
pulled open or breached during normal handling of the package. The
fold protection panel is typically secured utilizing conventional
tape that is used with sterilization wrap. Desirably, the fold
protection panel covers the edges of the barrier protection panel
after it is folded around the content to be sterilized to form a
package. The fold protection panel covers these edges to prevent a
worker inadvertently opening the folded barrier protection panel.
In addition, the fold protection panel shields the edges from
snags, pulls or other phenomenon that could impart a peel force to
these edges that would cause the panel attachment means to detach.
That is, the configuration of the multi-panel sterilization
assembly utilizes the fold protection panel to protect exposed
edges of the barrier panel after the barrier panel has been folded
around content to be sterilized to form a package.
[0083] According to the present invention, the barrier panel may be
composed of at least one layer of a breathable nonwoven material.
Desirably, the breathable nonwoven material is a laminate composed
of a layer of spunbonded filaments, a layer of meltblown fibers,
and a layer of spunbonded filaments--also called
spunbonded-meltblown-spunbonded material which is commonly referred
to by the acronym SMS. The two outer layers of SMS are a spunbonded
material made from extruded polyolefin fibers, or filaments, laid
down in a random pattern and then bonded to one another. The inner
layer is a meltblown layer also made from extruded polyolefin
fibers generally of a smaller diameter than the fibers in the
spunbonded layers. As a result, the meltblown layer provides
increased barrier properties due to it fine fiber structure which
permits the sterilizing agent to pass through the fabric while
preventing passage of bacteria and other contaminants. Conversely,
the two outer spunbonded layers provide a greater portion of the
strength factor in the overall laminate. The laminate may be
prepared using an intermittent bond pattern that is preferably
employed with the pattern being substantially regularly repeating
over the surface of the laminate.
[0084] As noted above, the flexible multi-panel sterilization
assembly 100 may include at least one pull tab 300 extending from
the second end 118 of the barrier panel 102. The pull tab 300 may
be formed of the same material as the barrier panel or may be
formed of one or more different materials. The pull tab is a
feature that can be grasped by a person unfolding a sterilized
package formed of a folded flexible multi-panel sterilization
assembly containing sterilized content without compromising the
sterile field formed by the unfolded content-contacting portions of
the barrier panel. The pull tab 300 may be attached to the barrier
panel or it may be integral or unitary with the barrier panel. In
an aspect of the invention, the barrier panel at or adjacent the
edges near the pull tab 300 may be bonded together utilizing a seam
such as, for example, a stitched seam, an ultrasonic bond seam,
adhesive bond seam, thermo-mechanical bond seam (e.g., a bar seal
seam) or combinations thereof to provide sufficient stiffness,
rigidity or support to that portion of the barrier panel so that
folding or creasing of the barrier panel is reduced or eliminated
when force is applied to the pull tab 300 during unwrapping. This
is important to preserve the sterility of the contents during
unwrapping. For example, the second edge 122 and the fourth edge
126 illustrated in FIG. 2B may be partially or substantially bonded
to provide such a configuration. As another example, the second
edge 122 illustrated in FIG. 3A may be partially or substantially
bonded to provide the desired configuration. As yet another
example, the second edge 122 and/or the fourth edge 126 and fifth
edge 128 illustrated in FIG. 3A may be partially or substantially
bonded to provide the desired configuration.
[0085] In an embodiment of the invention, the sterilization
assembly may further include one or more discrete reinforcement
elements in the content receiving region. In addition to
reinforcing the barrier panel, the reinforcement element may define
an area for receiving content to be sterilized. The reinforcement
elements may include one or more layers of materials selected from
fibrous webs, impermeable films, permeable or porous films,
apertured films, foams and combinations thereof. For example,
fibrous webs may include those that are woven and nonwoven. Woven
webs may include natural or synthetic materials or blends of the
same. As examples, natural materials could be weaves of cotton
yarn, and synthetic materials could be weaves of polypropylene,
polyester, or nylon yarn and the like. Nonwoven webs may include,
for example, spunbond, meltblown, carded webs, wet formed or
airlaid webs, or laminates of the same (e.g.,
spunbond/meltblown/spunbond). Such nonwoven webs may also include
natural or synthetic materials or blends of the same. The
reinforcement elements may include one or more layers of material
selected from permeable or impermeable films or laminates of the
same. Permeable films may be apertured or be microporous.
Impermeable films can be monolayer or coextruded and can be
comprised of film materials including, for example, polyethylenes,
polypropylenes, copolymers thereof, vinyls, metal foils, and the
like. It should also be noted said films may also be laminated with
fibrous webs, described above.
[0086] In particular embodiments of the invention, the
reinforcement elements may include a layer of polyethylene film. A
useful film for reinforcement elements is a blended polyethylene
film that includes both high density polyethylene and low density
polyethylene. As delineated in the examples below, such a
reinforcement element is effective in reducing pressure hole
formation.
[0087] Reinforcement elements are discrete zones of the barrier
panel of containing additional material or treatments to reduce the
likelihood that the barrier panel will be compromised by pressure
cuts, pressure holes, tears or the like in the locations where the
content is likely to concentrate forces against the material(s) of
the barrier panel. It is envisioned that relative to the
material(s) of the barrier panel, the reinforcement elements can be
less permeable or even impermeable to hot air, steam, or other
sterilization gas, while still allowing for proper sterilization
and removal of sterilant gas. It has been found that acceptable
sterilization and removal of sterilant gas will take place if the
permeability of the sterilization package web is greater than about
25 cubic feet per minute (cfm) as characterized in terms of Frazier
permeability. As such, a reinforcement element material that is
impermeable or less permeable than the sterilization package
material is acceptable, as long as the overall sterilization
package is adequately permeable (i.e., greater than about 25 cfm).
If an impermeable or less permeable reinforcement element material
is desirable, the permeability of the overall sterilization package
can be varied by changing the area covered by the reinforcement
element. It is desirable that the sterilization package web
maintain an overall permeability of at least about 25 cfm.
[0088] The reinforcement elements may also be configured to
identify the content receiving region 130 of the barrier panel 102.
Alternatively and/or additionally the reinforcement elements may be
configured to cooperate with the panel attachment means to identify
the content receiving region 130 of the barrier panel 102. For
example, the reinforcement elements may be in the form of discrete
shapes placed within the content receiving region. FIGS. 5A through
5D are illustrations of exemplary flexible multi-panel
sterilization assemblies 100 composed of a barrier panel 102, panel
attachment means 106 and a fold protection panel 108 and which
further include reinforcement elements 302.
[0089] FIG. 5A illustrates a flexible multi-panel sterilization
assembly 100 in which four reinforcement elements 302 are
positioned at spaced apart locations in the content receiving
region 130 of the barrier panel 102 generally at the locations that
correspond to the corners of a sterilization tray or similar
content. FIG. 5B illustrates a flexible multi-panel sterilization
assembly 100 in which two reinforcement elements 302 are positioned
at spaced apart locations on the barrier panel 102 extending from
the pre-determined fold line 116 to a fourth edge 126 and a fifth
edge 128 of the barrier panel 102 generally opposite the
pre-determined fold line 116. The two reinforcement elements 302
are positioned in the content receiving region 130 generally at the
locations that correspond to the corners of a sterilization tray or
similar content. FIG. 5C illustrates a flexible multi-panel
sterilization assembly 100 in which two reinforcement elements 302
are positioned at spaced apart locations on the barrier panel 102
generally parallel to the pre-determined fold line 116 between the
two panel attachment means 106 at or adjacent a first edge 120 and
a third edge 124. The two reinforcement elements 302 are positioned
in the content receiving region 130 generally at the locations that
correspond to the corners of a sterilization tray or similar
content. FIG. 5D illustrates a flexible multi-panel sterilization
assembly 100 in which two reinforcement elements 302 are positioned
at spaced apart locations on the barrier panel 102 and the fold
protection panel 108. The two reinforcement elements 302 extend in
generally parallel configuration from a distal end 144 of the fold
protection panel 108 to a fourth edge 126 and a fifth edge 128 of
the barrier panel 102. The two reinforcement elements 302 are
positioned in the content receiving region 130 generally at the
locations that correspond to the corners of a sterilization tray or
similar content. It should be noted that a pull tab or tail 300 is
illustrated in FIGS. 5A to 5D as extending out from underneath the
barrier panel. This representation is merely intended to illustrate
that a pull tab or tail 300 may be included and not particularly
how it is preferably configured.
[0090] Of course, the reinforcement elements may have a wide
variety of shapes, sizes and other configurations. FIGS. 6A and 6B
are illustrations of exemplary reinforcement elements 302. FIG. 6A
illustrates reinforcement elements 302 having generally triangular
configurations. FIG. 6B illustrates an exemplary reinforcement
element 302 composed of several overlapping triangular elements.
Alternatively and/or additionally, the reinforcement element 302
illustrated in FIG. 6B may be formed by a single piece of material.
Other shapes and configurations are contemplated such, for example,
H patterns, X patterns, or the like.
[0091] In an aspect of the invention, the construction of the
disposable flexible multi-panel sterilization assembly may be based
on two primary pieces of material. Referring now to FIG. 7, there
is shown an illustration of an exemplary disposable flexible
multi-panel sterilization assembly 100 in exploded or broken apart
view revealing a first layer 304 of a material and a second layer
306 of material. In this configuration, the first layer 304 of
material and the second layer 306 of material overlap to define the
barrier panel 102. Generally speaking, these layers may be joined
by adhesives, ultrasonic bonding, thermo-mechanical bonding or the
like. The layers are desirably joined at or adjacent at least two
of the edges and along the pre-determined fold line. For example,
the layers may be joined along the first edge 120 and the third
edge 124. The bonding may be a complete seam or the edge may be
partially bonded along only one or a few portions of the edge.
Alternatively and/or additionally, the bonding may be intermittent
or discontinuous along all or a portion of the respective edge. Of
course, other edges may also be bonded or the layers may be bonded
together across all or portions of their entire surface area. The
region where there is no overlap of the first layer 304 of material
and second layer 306 of material forms the fold protection panel
108. Generally speaking, the first layer 304 of material and the
second layer 306 of material may be the same material or they may
be different materials. For example, the first layer 304 of
material may be single layer or multiple layers of spunbond
nonwoven material, a lightweight nonwoven laminate material, or a
material that lacks the level of barrier properties (or other
characteristics) that may be desired for the barrier panel. The
second layer 306 of material desirably has a higher level of
barrier properties than the first layer 304 of material. For
example, the second layer 306 of material may be a laminate of
nonwoven fabrics such as SMS material. The second layer 306 of
material may have a different color and/or pattern than the first
layer 304 of material. For example, the first layer 304 of material
may have a first color (e.g., a blue color), a dark color, or a
specific color on a color scale and the second layer 306 of
material may have no color (e.g., white), a second color (e.g., a
light color), or a specific color on a color scale that contrasts
with the first color.
[0092] As generally shown in FIG. 7, the first surface 110 of the
disposable flexible multi-panel sterilization assembly 100 may be
formed of the second layer 306 of material and the first layer 304
of material and the second opposing surface 112 may be formed of
the first layer 304 of material. It is contemplated that the first
surface 110 of the disposable flexible multi-panel sterilization
assembly 100 may be formed of the first layer 304 of material and
the second opposing surface 112 may be formed of the first layer
304 of material and the second layer 306 of material. It is also
contemplated that other combinations of layers may be used such
that two layers of material generally corresponding in size to the
first layer of material 304 may sandwich or enclose an intermediate
layer of material corresponding in size to the second layer of
material 306 such that the first surface 110 and the second
opposing surface 112 are generally the same such that one surface
does not reveal two discrete layers of material (i.e., does not
show both the first layer 304 of material and the second layer 306
of material).
[0093] It is contemplated that the color differentiation or
contrast between the first layer 304 of material and the second
layer 306 of material may be useful to function as an indicator
that barrier properties of the barrier panel may be
compromised.
[0094] Referring now to FIG. 8, there is shown an illustration of
an exemplary disposable flexible multi-panel sterilization assembly
100 in exploded or broken apart cross-sectional view revealing a
first layer 304 of a material and a second layer 306 of material.
In this configuration, the first layer 304 of material and the
second layer 306 of material overlap to define the barrier panel
102. The region where there is no overlap of the first layer 304 of
material and second layer 306 of material forms the fold protection
panel 108. The cross-sectional view illustrates reinforcement
elements 302. The reinforcement elements 302 may be present on the
first surface 110 to desirably identify the content receiving
region 130 of the barrier panel 102 between the panel attachment
means 106. Alternatively and/or additionally, the reinforcement
elements 302 may be located on the second opposing surface 112 of
the barrier panel.
[0095] In an aspect of the present invention, it has been
discovered that pressure holes and pressure cuts most commonly
propagate from the outside of a wrapped sterilization tray or other
content (i.e., outside the content enclosed by sterilization wrap
fabric) rather than propagating from the sterilization tray or
other content that is wrapped by or otherwise enclosed by
conventional sterilization wrap fabric. The applicants have
discovered that locating the reinforcement elements 302 on the
second opposing surface 112 of the barrier panel provides an
unexpected advantage because the second opposing surface 112 of the
barrier panel 102 is the portion of the disposable flexible
multi-panel sterilization assembly 100 that does not contact the
content (e.g., sterilization tray) and which typically forms the
outside of a wrapped package. Reinforcement elements 302 located on
the second opposing surface 112 provide more efficient protection
against pressure holes and pressure cuts because the inventors have
discovered that pressure holes and pressure cuts tend to propagate
from the outside of a wrapped package. While the inventors should
not be held to any particular theory of operation, it has been
discovered that pressure cuts and pressure holes are more
frequently caused when content enclosed by sterilization wrap
contacts an irregular surface with sufficient force during a single
contact event or during multiple contact events such that the
irregular surface concentrates the force to generate energy that
causes failure.
[0096] Such contact events are frequently encountered when an
individual wrapped sterilization tray or stacks of wrapped
sterilization trays (particularly those containing excessive loads)
are transported by cart or other similar device and the cart or
similar device stops abruptly (e.g., due to impact), encounters
bumps or abrupt shocks. Other sources of contact events occur when
wrapped trays are dropped; when wrapped trays are dragged or pushed
across a smooth surface; when a wrapped tray contacts a hard
surface; and/or when excessive pressure is applied to a wrapped
tray. For example, in removing a heavy tray from a shelf, the front
end of the tray may be lifted resulting in the entire weight of the
tray being concentrated on the back end. Furthermore, the tray may
be pulled across the shelf before being lifted from its surface.
These events, separate or in conjunction, may produce pressure cuts
or holes. As another example, dropping a wrapped tray (even a small
distance) such that the wrap is pinched between the tray or wrapped
contents and a hard surface, such as the surface of a cart or
storage shelf, may produce pressure holes. In addition,
transporting events, for instance transporting a loaded tray on a
cart to different areas of the hospital may produce pressure holes
through vibration, rapid stopping or rolling over an uneven
surface.
[0097] FIG. 9 illustrates a standard sterilization tray T
(approximate length=20 inches (.about.510 mm), width=10.5 inches
(.about.270 mm) and height=3.5 inches (.about.88 mm)) and a
multi-panel sterilization assembly of the present invention
generally in accordance with FIG. 3A prior to wrapping. It should
be noted that the barrier panel 102 has two plies of material and
the fold protection panel 108 has a single ply of material.
EXAMPLES
[0098] The ability of various disposable flexible multi-panel
sterilization assemblies were evaluated in the following examples
to determine their resistance to forming pressure holes using the
Pressure Hole Test Procedure described below.
[0099] Pressure Hole Test Procedure
[0100] The Pressure Hole Test procedure utilizes weights placed in
conventional wire mesh surgical trays. The load chosen may range
from light loads such as less than three pounds, to loads
encountered during normal use, to those that would be considered
excessive relative to standard conditions. The loaded wire mesh
surgical trays are wrapped in the sterilization wrap to be tested.
The wrapped trays are placed on a conventional sterilization roller
cart having a wire mesh shelf. The cart containing the wrapped
trays is rolled over a conventional no-slip mat to approximate the
type of rough surface which may be found on a hospital floor.
[0101] The specific equipment used in the test includes
conventional plate weights available in 2.5 lb. increments (2.5
lbs., 5 lbs., 7.5 lbs., etc., to 30 lb). Conventional hard metal
wire mesh surgical trays (having an approximately 9 inch by 9 inch
wire frame base) are wrapped in the barrier material to be tested.
An exemplary tray is shown in FIGS. 10 and 12. Trays utilized in
the test have a conventional alternating square weave pattern in
which the warp strand passes alternately over and then under the
weft strands. The warp and weft strands were approximately 0.5
millimeters in diameter and defined uniform squares approximately 5
millimeters long on each side. Around the base of the metal tray is
a reinforcing wire approximately 5 millimeters in diameter that
extended along the periphery of the entire tray to form a base.
Such trays are available from Hupfer.RTM. Metallwerke GmbH &
Co. KG of Coesfeld, Germany.
[0102] Wrapped trays are placed on a conventional medical tray
sterilization roller cart equipped with a hard metal wire mesh
shelf, as shown in FIG. 12. The tray roller cart includes a
conventional alternating square weave pattern in which the warp
strand passed alternately over and then under the weft strands. The
warp and weft strands were approximately 1/16 inch (1.5
millimeters) in diameter and defined uniform squares approximately
14 millimeters long on each side. An exemplary medical tray roller
cart is the Amsco Hyvac General Purpose Sterilizer Cart available
from Steris Corporation of Mentor, Ohio. The cart has four hard
plastic wheels having a wheel width of approximately 1 inch and a
wheel diameter of approximately 5 inches.
[0103] The medical tray roller cart is pushed over a floor mat
having a uniform distribution of openings in the mat surface. The
specific floor mat used in the examples of the present invention
was the NoTrax.RTM. floor mat from Superior Manufacturing Group,
Inc. of Chicago, Ill., as shown in FIG. 11. The mat was 3
feet.times.6 feet in size and approximately 3/8 inch (8.5
millimeters) thick. The mat was composed of a pliable material of
the type commonly used in ergonomic floor mats with a hardness
similar to a hard rubber eraser or shoe sole. The mat had 0.5 inch
by 2 inch (1.25 centimeter by 5.1 centimeter) approximately
openings at a uniform distribution of approximately 20 holes per
square foot.
[0104] The general test protocol is as follows:
[0105] 1. Place the desired amount of weight in each of four (4)
empty trays. Typically, a series of different tray weights are
tested, ranging from 2.5 lbs to 40 lbs.
[0106] 2. Gently place each weighted tray on its own sheet of
barrier material. Wrap each tray making sure material is snug
around the base of the tray. Wrap the tray using the conventional
envelope fold wrapping pattern as illustrated in FIGS. 4A-4E.
[0107] 3. Carefully place the wrapped sterilization tray on the
wire shelf of the medical tray cart so that two corners of the
sterilization tray are on the wire portion of shelf. The remaining
two corners will hang over the edge of the shelf. Sterilization
trays should be set down on the shelf not slid onto the shelf. Once
trays are on shelf, avoid adjusting or sliding the tray.
[0108] 4. Roll the medical tray cart at brisk walking pace
(approximately 5 to 6 feet per second) over and back on the
NoTrax.RTM. floor mat surface for a total of 5 cycles, each cycle
constituting moving the cart completely across the mat in one
direction and then completely back across the mat in the opposite
direction. The cart wheels should be positioned approximately three
inches from the edge of the mat before rolling the medical tray
cart onto and across mat. After the cart is pushed to one end of
mat, the tester should walk to the opposite end of the cart and
push the cart back over the mat, such that the tester is always
pushing the cart walking forward, never pulling the cart walking
backwards. The cart should be pushed on a trajectory that does not
result in the cart wheels being pushed off the mat to the left or
right. Upon completing 5 cycles, rotate each of the trays 180
degrees such that tray corners previously hanging off the shelf now
are on the wire mesh shelf. Repeat the sequence of rolling the cart
at a brisk walking pace over the mat for a total of 5 cycles.
[0109] 5. Unwrap each of the trays while the trays are still
resting on the cart by unfolding the barrier material from each
tray. Lift and remove each of the trays off of the barrier material
which remains resting on the cart.
[0110] 6. Remove the barrier material samples and inspect each
sample individually under low power optical magnification (e.g.,
from about 0.7.times. to about 3.times. optical magnification). To
aid in inspection of barrier material for holes, the samples can be
placed onto a light table or held in front of a light source.
Preferably an optical microscope with a backlight feature can be
used. Pinholes in the barrier material are visible as bright
pinholes due to light passing through the material. The bright
pinholes were inspected at low power magnification for
confirmation. Visual inspection of low basis weight barrier
material (e.g., 35 grams per square meter or less) occasionally
presented bright pinholes that did not appear to be the result of
pressure holes or pressure cuts or other failure modes. Visual
inspection using low power optical magnification was used to
identify fused fibers and other characteristics of pressure holes
and pressure cuts in order to determine whether the pinhole was
characterized as a failure.
[0111] 7. To determine the failure rate, the four discrete portions
of an individual barrier material that contacted each bottom corner
surface of an individual sterilization tray are each considered an
individual, independent sample. The visual confirmation of a hole
at a corner is considered a failure of that particular corner.
During a normal test cycle, four separate sterilization trays
loaded to the same designated weight are each wrapped with a
barrier material and tested. This setup results in sixteen
individual, independent samples of the barrier material at the
designated weight. This number of independent samples is based on
one individual barrier material contacting each of four corners of
a sterilization tray at the designated weight resulting in four
independent samples from each wrapped sterilization tray. If four
sterilization trays are tested at a designated weight, the number
of independent samples is determined by multiplying the four
independent samples per sterilization tray by four sterilization
trays.
[0112] For each example, the dimensions of each of the barrier
material samples were approximately 22 inches by 18 inches (56 cm
by 46 cm).
Example 1
[0113] Samples of the barrier materials identified in Table 1 were
tested in accordance with the procedure set forth above.
TABLE-US-00001 TABLE 1 Sterilization Wrap Sample ID Description
Basis Weight 1A KC100 1.05 osy (~36 gsm) 1B KC200 1.20 osy (~41
gsm) 1C KC400 1.85 osy (~62 gsm) 1D Bicomponent SMS 2.05 osy (~69
gsm) 1E KC100 with polyethylene 1.4 osy (~47 gsm) film
reinforcement elements
[0114] Samples 1A-1C are barrier materials that are formed from
single-ply nonwoven fabrics commercially available from
Kimberly-Clark Corporation of Roswell, Ga. as KIMGUARD.RTM.
Sterilization Wrap under the specific trade designations KC100,
KC200 and KCKC400. These barrier materials are three layer
laminates of spunbonded-meltblown-spunbonded layers which is also
commonly referred to by the acronym SMS. The two outer layers of
SMS are a polypropylene spunbonded material and the inner layer is
a meltblown layer also made from polypropylene.
[0115] Sample 1D is an SMS laminate that utilizes a bicomponent
spunbond formed from nylon and polypropylene as the two exterior
nonwoven layers with a conventional meltblown center layer. The SMS
was thermally bonded using a diamond dot pattern and had a basis
weight of about 1.74 osy (about 59 gsm).
[0116] Sample 1E is KC100 which further includes reinforcement
elements positioned on the barrier material so that they align with
the corners of the tray. The sterilization tray was placed on the
four reinforcing elements with each corner of the sterilization
tray aligned to rest at approximately the center of each
reinforcing element. Each of the reinforcing elements was
triangular in shape with dimensions of approximately 3 inches by 2
inches by 3.6 inches. The reinforcement elements were disposed
between the barrier material and the tray, and were not bonded to
the barrier material. The reinforcement elements in Sample 1E were
cut from commonly available plastic film grocery store bags.
Specifically, these reinforcement elements were formed from an
unperforated polyethylene film having a thickness of about 0.5 mil,
and which is believed to include at least about 90% by weight high
density polyethylene (HDPE) and less than about 10% by weight low
density polyethylene (LDPE). The basis weight for sample 1E was
estimated by adding the estimated additional basis weight of the
polyethylene film reinforcement elements to the basis weight of
K-C100.
[0117] All sample groups in this example were subjected to the
Pressure Hole Test Procedure described herein. At least sixteen
(16) corners were tested within each of the sample groups for each
tray weight given in Table 2.
TABLE-US-00002 TABLE 2 Sample Sample Sample Sample 1E KC100 1A 1B
1C Sample with rein- KC100 KC200 KC400 1D SMS forcement Tray Wt. (%
(% (% Bico (% elements (lbs) Failure) Failure) Failure) Failure) (%
Failure) 2.5 50% 19% n/a n/a n/a 5 69% 31% 19% 13% 13% 7.5 50% 44%
14% 25% 25% 10 75% 94% 25% 38% 25% 12.5 81% 81% 58% 71% 63% 15 94%
94% 63% 79% 56% 17.5 94% 100% 89% 75% 75% Average % 73% 66% 45% 50%
43% Failure
[0118] Table 2 shows the failure rates of each of the barrier
materials for different tray weights as a result of the Pressure
Hole Test Procedure. The percentage of corners which demonstrated
at least one pinhole and thereby constituted a failure was
calculated by dividing the number of failed corners by the total
number of corners tested for each sample for each tray weight. The
data for other samples and tray weights was similarly
calculated.
[0119] The Average Percent Failure was calculated for each sample
group for all tray weights. There are many ways to calculate an
average percent failure for the various samples. In the examples
herein, the Average Percent Failure was calculated as the average
of the failure rates for each type of material sample used.
Specifically, the Average Percent Failure for Sample 1A was
calculated by adding the percent failure for all tray weights for
Sample 1A and dividing by the number of tray weights. In general,
the Average Percent Failure of Sample 1E was comparable to the
average percent failure rate of Sample 1C, which utilizes a heavier
basis weight barrier material as compared to Sample 1E. These
results demonstrate that the use of lighter basis weight barrier
materials with HDPE film reinforcement elements in the areas of the
tray corners can reduce the failure rate of such lighter basis
weight barrier materials so that their performance is comparable to
heavier and more expensive barrier materials.
Example 2
[0120] Samples of the barrier materials identified in Table 3 were
tested in accordance with the Pressure Hole Test Procedure set
forth above.
TABLE-US-00003 TABLE 3 Sterilization Approximate Basis Wrap Sample
ID Description Weight 2A KC100 1.05 osy (~36 gsm) 2B KC300 1.41 osy
(~48 gsm) 2C KC400 1.85 osy (~63 gsm) 2D KC100 with PVDC film 1.04
osy (~47 gsm) reinforcement elements
[0121] As shown in Table 3, samples 2A-2C are barrier materials
that are formed from single-ply nonwoven fabrics commercially
available from Kimberly-Clark Corporation of Roswell, Ga. as
KIMGUARD.RTM. Sterilization Wrap under the specific trade
designations KC100, KC300 and KC400. As noted above, these barrier
materials are SMS laminates.
[0122] In Sample 2D, four reinforcement elements each made of
polyvinylidene chloride (PVDC) were placed onto a KC100 barrier
material in locations so that the PVDC reinforcement elements were
positioned below each of the corners of the tray that was wrapped
with the barrier material. The PVDC film utilized was a commonly
available protective film wrapping suitable for use with food and
also referred to as cling wrap, cling film or food wrap.
Specifically, Saran.TM. Wrap Premium was utilized (Saran.TM. is a
registered trademark of SC Johnson & Son, Inc.)
[0123] Table 4 shows the failure rates of the samples delineated in
Table 3.
TABLE-US-00004 TABLE 4 Sample 2D KC100 with Sample 2A Sample 2B
Sample 2C reinforcement Tray Wt KC100 (% KC300 (% KC400 (% elements
(% (lbs) Failure) Failure) Failure) Failure) 2.5 88% 56% 0% 0% 5
100% 88% 38% 69% 7.5 100% 88% 38% 69% 10 100% 100% 75% 94% 12.5
100% 100% 81% 100% 15 100% 100% 100% 100% 17.5 100% 100% 100% 100%
Average % 98% 90% 62% 76% Failure
[0124] Sample group 2D which included reinforcement elements
demonstrated improved performance over Sample group 2A, although
both sample groups were formed of the same base barrier material.
However, the decreased failure rate was not as significant as the
improved performance demonstrated by Sample 1E.
Example 3
[0125] Samples of the barrier materials identified in Table 3 were
tested in accordance with the Pressure Hole Test Procedure set
forth above.
TABLE-US-00005 TABLE 5 Sterilization Approximate Basis Wrap Sample
ID Description Weight 3A KC200 1.05 osy (~36 gsm) 3B KC300 1.41 osy
(~48 gsm) 3C KC400 1.85 osy (~63 gsm) 3D Spunbond/Film/Spunbond
1.40 osy (~47 gsm)
[0126] Samples 3A-3C in Table 5 are commercially available
single-ply nonwoven fabrics commercially available as KIMGUARD.RTM.
Sterilization Wrap under the specific trade designations KC200,
KC300 and KC400.
[0127] Sample 3D is a spunbond-film-spunbond laminate. Two 0.45 osy
polypropylene spunbond layers were placed on either side of a
polyethylene film which had a width of approximately 13 inches. The
spunbond layers together approximate a KC300 barrier material in
basis weight subtracting out the center layer of meltblown. The
film was disposed in the center of the spunbond layers such that,
after thermally point bonding the film layer to the spunbond
layers, the film layer was positioned beneath the entire perimeter
of the tray. The film was formed from a blend of HDPE and LDPE and
is believed that at least 90% by weight of the film was HDPE and
less than 10% by weight of the film was LDPE.
TABLE-US-00006 TABLE 6 Sample Sample Sample Sample 3A KC 3B KC 3C
KC 3D SB/ Tray Wt 200 (% 300 (% 400 (% Film/SB (% (lbs) Failure)
Failure) Failure) Failure) 7.5 56% 44% 14% 38% 10 83% 88% 25% 63%
12.5 100% 94% 58% 67% Average % 80% 75% 32% 56% Failure
[0128] Table 6 shows the percent failure of each Sample group.
Although the total basis weights of Sample 3B and 3D are similar,
the Average Percent Failure of Sample 3D is notably less than
Sample 3B.
[0129] While it may not be optimal to place a single wide
reinforcement element of polyethylene film onto a sterilization
wrap, it has been shown to provide decreased failures due to
formation of pinholes.
[0130] The examples demonstrate that, when using reinforcement
elements in conjunction with a relatively low basis weight barrier
material (e.g., about 1 osy), low basis weight reinforcement
elements (e.g., from about 0.1 to about 1 osy) result in
substantial reduction in pressure hole formation in the barrier
material.
[0131] When using reinforcement elements in conjunction with a
moderate basis weight barrier material (e.g., basis weight about
1.8 osy), the use of low basis weight reinforcement elements (e.g.,
basis weights from about 0.1 to about 1 osy) on the interior
surface of the barrier material (i.e., the interior surface
contacting the content to be sterilized or the sterilized content)
results in substantial reduction in pressure hole formation in the
barrier material. A similar plateau, where further increasing the
basis weight of the reinforcement element on the interior surface
no longer provides additional benefit to the barrier material is
believed to exist.
[0132] Use of a relatively light weight reinforcement element
(.about.1 osy) reduces pressure hole formation in all basis weights
of barrier materials (barrier materials ranging from 1 osy to 2
osy). As the basis weight of the barrier material is increased,
basis weight of the barrier material itself becomes the most
predominant factor for reinforcement and reduced pressure hole
formation. But light weight reinforcement elements still reduce
pressure hole formation in the heaviest barrier materials tested
(.about.2 osy), as compared to when reinforcement elements are not
used. Extrapolation would suggest that a barrier material of 3 osy
or greater would not benefit from a 1 osy reinforcement
element.
[0133] Generally speaking, the results of this testing show that
Percent Failure decreases as the basis weight of the barrier
material is increased. However, when reinforcing elements are
positioned between the sterilization tray and the barrier material,
an increase in the basis weight of the combined components (i.e.,
the barrier material basis weight is constant and reinforcing
element basis weight increases) results in a decrease in Percent
Failure that levels off at a much higher rate of failure than for a
barrier material having a corresponding basis weight.
[0134] Surprisingly, when reinforcing elements are positioned on
the outside of the barrier material such that the reinforcing
elements come between the barrier material and the surface of a
shelf (at least at the corners of the sterilization tray), an
increase in the basis weight of the combined components (i.e., the
barrier material basis weight is constant and reinforcing element
basis weight increases) results in a decrease in failure rates that
compares favorably to a barrier material having a corresponding
basis weight.
[0135] This is interpreted as providing a sterilization assembly in
which the basis weight of the barrier panel may be reduced or at
least held to a low level while generating a profile of resistance
to pressure cuts and pressure holes that was previously provided
only by increasing the basis weight of the entire sterilization
wrap material.
[0136] While particular embodiments of the present invention have
been described herein; it will be apparent to those skilled in the
art that alterations and modifications may be made to the described
embodiments without departing from the scope of the appended
claims.
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