Patent Application
20130001283
The present invention relates in general to disposable wraps used to contain content to be sterilized and store that content aseptically until use.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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%.
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.
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.
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.
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.
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.
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:
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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
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.
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 (˜13 mm) to about 2 inches (˜51 mm). Desirably, the pre-determined fold line is offset by about 1 inch (˜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.
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.
While the barrier panel 102 of
For example and referring to
Referring to
Referring again to
In an aspect of the invention, the barrier panel of the various illustrated configurations may have a width of from about 12 inches (˜30 cm) to about 50 inches (˜127 cm). Desirably, the barrier panel may have a width of from about 18 inches (˜46 cm) to about 40 inches (˜102 cm). Even more desirably, the barrier panel may have a width of from about 20 inches (˜51 cm) to about 30 inches (˜76 cm). The barrier panel may have a length of from about 7 inches (˜18 cm) to about 50 inches (˜127 cm). Desirably, the barrier panel may have a length of from about 15 inches (˜39 cm) to about 40 inches (˜102 cm). Even more desirably, the barrier panel may have a length of from about 25 inches (˜64 cm) to about 30 inches (˜76 cm).
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.
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.
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
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
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.
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.
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® 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.
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.
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
Referring to
Referring again to
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.
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 (˜30 cm) to about 50 inches (˜127 cm). Desirably, the fold protection panel may have a width of from about 18 inches (˜46 cm) to about 40 inches (˜102 cm). Even more desirably, the fold protection panel may have a width of from about 20 inches (˜51 cm) to about 30 inches (˜76 cm). The fold protection panel may have a length of from about 6 inches (˜15 cm) to about 30 inches (˜76 cm). Desirably, the fold protection panel may have a length of from about 8 inches (˜20 cm) to about 20 inches (˜51 cm). Even more desirably, the fold protection panel may have a length of from about 12 inches (˜30 cm) to about 15 inches (˜38 cm).
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.
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.
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.
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 (˜102 by ˜25 mm).
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.
Referring now to
As generally illustrated in
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
Referring now to
Referring now to
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.
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
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.
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.
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.
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.
Of course, the reinforcement elements may have a wide variety of shapes, sizes and other configurations.
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
As generally shown in
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.
Referring now to
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.
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.
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.
Pressure Hole Test Procedure
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.
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
Wrapped trays are placed on a conventional medical tray sterilization roller cart equipped with a hard metal wire mesh shelf, as shown in
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® floor mat from Superior Manufacturing Group, Inc. of Chicago, Ill., as shown in
The general test protocol is as follows:
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.
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
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.
4. Roll the medical tray cart at brisk walking pace (approximately 5 to 6 feet per second) over and back on the NoTrax® 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.
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.
6. Remove the barrier material samples and inspect each sample individually under low power optical magnification (e.g., from about 0.7× to about 3× 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.
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.
For each example, the dimensions of each of the barrier material samples were approximately 22 inches by 18 inches (56 cm by 46 cm).
Samples of the barrier materials identified in Table 1 were tested in accordance with the procedure set forth above.
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® 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.
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).
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.
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 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.
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.
Samples of the barrier materials identified in Table 3 were tested in accordance with the Pressure Hole Test Procedure set forth above.
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® Sterilization Wrap under the specific trade designations KC100, KC300 and KC400. As noted above, these barrier materials are SMS laminates.
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™ Wrap Premium was utilized (Saran™ is a registered trademark of SC Johnson & Son, Inc.)
Table 4 shows the failure rates of the samples delineated in Table 3.
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.
Samples of the barrier materials identified in Table 3 were tested in accordance with the Pressure Hole Test Procedure set forth above.
Samples 3A-3C in Table 5 are commercially available single-ply nonwoven fabrics commercially available as KIMGUARD® Sterilization Wrap under the specific trade designations KC200, KC300 and KC400.
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 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.
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.
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.
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.
Use of a relatively light weight reinforcement element (˜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 (˜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.
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.
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.
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.
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.
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.
