Patent Application
20130294970
The present invention, in particular, relates to sterilization wraps. Sterilization wraps are mainly used in CSSD (Central Sterilization & Supplies Department) of hospitals and healthcare facilities for the packaging, the sterilization and the maintenance of the sterile state of re-usable, freshly washed, and disinfected medical devices such as scalpels, pliers, scissors, endoscopes, bedpans, tongue depressors or stents.
The invention also concerns a set comprising a medical device and a sterilization wrap according to the invention, said sterilization wrap containing said medical device, in particular in a sterilized state.
Sterilization wraps are generally made of special papers. Several types of papers for use in medical packaging are described in the patent literature.
WO 2007/058822 describes papers having enhanced microbial barrier properties for use in sterile packaging.
U.S. Pat. No. 6,349,826 describes papers comprising non-biodegradable binders.
JP 4 334 448 describes a biodegradable composite material comprising a layer of vegetal fibers covered with a layer of polylactic acid.
The sterilization wraps performances are described in the European Standard (EN 868-2:09): “Packaging for terminally sterilized medical devices—Part 2: Sterilization Wrap—Requirements and tests methods”:
This document also describes the properties that a sterilization wrap must present. In order to be in conformity with EN 868-2:09 standard, a nonwoven sterilization wrap should meet:
The fabrication of a sterilization wrap meeting the requirements of the EN 868-2:09 #4.2.2.3 is well known by a man skilled in the art. For example, it is well known that:
The known sterilization wraps may be nonwoven and may be made of:
These sterilization wraps may have a grammage of 80 g/m2 or less, usually below 70 g/m2.
The Applicant has surprisingly found that the use of biodegradable compounds in a sterilization wrap may allow the meeting of the EN 868-2 requirements while allowing the maintain of the grammage of the formed sheet.
Further, the use of biodegradable compounds may enhance the ability of the formed products to be recycled or decomposed.
It is an object of the present invention to provide a sterilization wrap meeting the EN 868-2:09 requirements, including the barrier properties requirements, and having a relatively low grammage.
It is another object of the invention to provide a sterilization wrap which is easy to get rid of.
The invention provides a medical material, intended to be sterilized, the medical material for producing a product chosen in the group consisting of: a surgical drape, optionally provided with a hole, a container filter, a sterile field, in particular to be used as a mayo or table cover; a gown, a sterilization wrap or a sterile bather system as per ISO 11607 standard definition, said material comprising or consisting of a, preferably nonwoven, sheet:
The cellulose fibers may be refined.
The sheet may have a grammage lying in the range 25 g/m2 to 75 g/m2, preferably 50 g/m2 to 75 g/m2, more preferably 55 g/m2 to 65 g/m2.
A sheet according to the invention may advantageously present a relatively low grammage nod an enhanced biodegradability while still meeting the strong requirements of EN 868-2:09 and presenting satisfying barrier properties, in particular to microorganisms.
The sheet may be considered as a paper and may be, as described hereunder, manufactured by papermaking methods.
According to the invention, a compound is “biodegradable” when the ratio of its biodegradation percentage on the biodegradation percentage of cellulose fibers is at least 75%, more preferably at least 80%, more preferably at least 90%. The biodegradation percentages may be measured according to ISO 14855 (2005) method: “Determination of the ultimate aerobic biodegradability and disintegration of plastic materials under controlled composting conditions”, after 24 days as described in the examples.
Preferably, a compound is regarded as “biodegradable” if it is decomposed, when exposed to the outside natural environment, under the climate of Paris (France), in less than 10 years, less than 5 years, preferably less than 1 year, preferably less than 6 months, preferably less than 2 months.
The “bio-based content” of a material is the ratio of its amount of organic carbon produced by the biomass or “bio-carbon” (i.e. from biologic origin, therefore excluding fossil or geologic materials) to its total amount of organic carbon.
The bio-based content quantifies, in a given material, the concentration of young (i.e. renewable) organic carbon in comparison with the concentration of old fossil organic carbon based resources.
The bio-based content may in particular be determined according to ASTM D6866-10.
A “fiber” is, in particular, presenting a ratio L/l of its length “L” to its width (largest dimension in a transversal cross-section) “l” of at least 10.
According to the invention, the expression “synthetic fiber” means a fiber produced artificially by a chemical or biochemical synthesis. A “synthetic fiber” is synonymous of a man-made fiber.
According to the invention, a “natural fiber” is a fiber which is not a “synthetic fiber” as defined above. A natural fiber may, in particular, be a cellulose-based fiber.
Unless otherwise stated, the amount, by dry weight, of cellulose fibers includes the amount, by dry weight, of the natural biodegradable fibers which are mainly cellulosic. Thus, if a sterilization wrap comprises 80%, by dry weight, of biodegradable fibers which are cellulosic (i.e. bamboo fibers) and 20%, by dry weight, of wood pulp, the amount, by dry weight, of cellulose fibers is 100%.
According to the invention, the fibers of a “layer” are intimately entangled. Woven or non woven mats are examples of layers.
According to the invention, the “binder” binds the fibers together thus improving the cohesiveness and mechanical properties of the sheet.
The invention also provides a product comprising a material as described above, said product being chosen in the group consisting of:
The invention also provides a kit comprising:
The invention also provides a method for manufacturing a material as described above comprising:
As used herein the term “on-line” shall mean a period during which the material is formed (e.g., on the wire), and includes any process from wet laying through finishing (e.g., drying, calendaring, sizing, etc.). The term “off-line” shall mean any period after the on-line period.
The above-mentioned steps a) to d) may have a positive impact on the obtaining of the desired barrier properties.
The cellulose fibers present in the furnish described in a) may be refined.
A refining step may be carried out before step a). The refining step may advantageously densify the fiber network and improve its cohesion.
The invention also provides a method of sterilization of a medical device, in particular chosen from scalpels, pliers, scissors, endoscopes, bedpans, tongue depressors or stents, comprising at least the following steps consisting in:
The kit described above may, in particular, be wrapped in an additional sterilization wrap before being introduced in the sterilizing unit.
The sterilizing unit may subject the kit to high pressure saturated steam (the sterilizing unit may be an autoclave), low temperature formaldehyde steam (LTFS), gamma-rays, electron beams, ethylene oxide or to a dry heat process.
The invention also provides the use of a sheet as described above as a component of a product having barrier properties, in particular to microorganisms.
Other features of the invention will become apparent when reading the following description in view of the drawings, wherein:
Fibers Comprised in the Sheet
The sheet may comprise biodegradable fibers selected from at least one of following ones: bleached wood pulp, semi-bleached wood pulp, unbleached wood pulp, cotton, abaca, straw, bamboo, viscose, hemp, jute, sisal, flax, kenaf, esparto or fibers from biodegradable or biocompostable polymers, according to EN 13432 standard, such as polylactic acid, polyhydroxyvalerate, polyhydroxybutyrate, polyhydroxyalkanoate, polyhydroxyhexanoate, polycaprolactone, polybutylene succinate, polybutylene succinate adipate or copolymers of them, optionally modified with starch based polymer, plastified cereal flour based polymers, optionally modified with copolyesters, plastified starch, such as corn starch, wheat starch or potato starch optionally modified with copolyesters.
Any suitable pulps may be utilized for obtaining the cellulose, for example, kraft pulps from coniferous and/or deciduous trees. Portions of the cellulose may be mechanically, chemically, thermo-mechanically, and/or chemi-thermo-mechanically pulped, as desired.
The natural biodegradable fibers may, in particular, be selected from at least one of the following ones: bleached wood pulp, semi-bleached wood pulp, unbleached wood pulp, cotton, abaca, straw, bamboo, hemp, jute, sisal, flax, kenaf or esparto.
The synthetic (i.e. man-made) biodegradable fibers may preferably be selected from at least one of the following ones: polylactic acid fibers, fibers of polyhydroxyalkanoate, fibers of polyhydroxyhexanoate, fibers of polycaprolactone, fibers of polybutylene succinate, fibers of polybutylene succinate adipate, viscose fibers, fibers of plastified starch, such as corn starch, wheat starch or potato starch optionally modified with copolyesters, or fibers of plastified cereal flour polymer.
The biodegradable fibers may have an average length lying in the range 0.1 mm to 30 mm, preferably 1 to 15 mm.
The biodegradable synthetic fibers may, in particular, have an average length of at least 2.5 mm, preferably 3 mm, more preferably 5 mm.
The biodegradable synthetic fibers may, in particular, have an average length of less than 12 mm.
The biodegradable natural fibers may have an average length of at least 1.5 mm, preferably 2.5 mm, more preferably 3 mm.
The biodegradable natural fibers may, in particular, have an average length of less than 10 mm.
The “average length” is, unless otherwise specified, the median length.
When the sheet comprises synthetic biodegradable fibers, the cellulose fibers may be present in an amount of 30% or more, preferably of 50% or more, in particular of 70% or more, by dry weight of the layer.
In one embodiment, the sheet may comprise, for a total of more than 80%, in particular more than 85%, in particular more than 90%, in percentages by dry weight on the basis of the layer:
When the sheet comprises a biodegradable binder, the cellulose fibers may be present in an amount of 30% or store, preferably of 50% or more, in particular of 70% or more, by dry weight of the layer.
In one embodiment, the sheet may comprise in percentages by dry weight on the basis of the layer:
When the sheet comprises natural biodegradable fibers, the cellulose fibers may be present in an amount of 50% or more, preferably of 70% or more, more preferably of 85% or more, by dry weight of the layer.
In one embodiment, the sheet may comprise, in percentages by dry weight on the basis of the layer, 60% or more of biodegradable fibers selected from abaca, sisal, cotton, bamboo fibers or mixtures thereof,
the total amount of cellulose fibers in the layer being more than 85%.
In a particularly preferred embodiment, the layer of the sheet comprises cellulose fibers and synthetic biodegradable fibers.
Biodegradable Binder and Additive
The sheet may comprise a biodegradable binder, in particular in an amount of 2% or more, in percentage by dry weight of the layer.
The biodegradable binder may, in particular, be non-fibrous.
The biodegradable binder may, in particular, be an adhesive.
The biodegradable binder may, in particular, be polymeric.
The sheet may, in particular, comprise at least 2%, and/or less than 30%, preferably less than 25%, preferably less than 20%, preferably less than 15%, preferably less than 10%, more preferably less than 5%, in percentage by dry weight of the layer, of a biodegradable binder and/or of an additive providing wet strength, cohesiveness or softness, for example chosen from potato, wheat, tapioca or corn starch, proteins of vegetal origin, such as soya protein or silk protein, proteins of animal origin, such as milk proteins, egg derivatives or algae derivatives, gelatin, collagen, chitine, the natural rubber latex, preferably of low protein grade, or a mixture of these compounds.
The sheet may comprise less than 20%, preferably less than 15%, preferably less than 12%, in percentage by dry weight of the layer, of a biodegradable hydrophobic additive, for example a vegetal modified oil, providing liquid repellency.
Non-Biodegradable Compounds
The sheet may have an amount less than 20%, preferably less than 15%, preferably less than 12%, preferably less than 10%, preferably less than 6%, in percentage by dry weight of the layer, of non-biodegradable compounds, said non-biodegradable compounds being, in particular, chosen from pigments, non-biodegradable hydrophobic additives or binders either acrylic or vinylic, polyurethane, polyvinyl alcohol, polyvinylacetate, styrene butadiene rubber, ethylene propylene heteropolymers or a mixture thereof.
The non-biodegradable binder may, in particular, be incorporated via a size-press process, a spraying process, a saturating process or a precipitating process.
The non-biodegradable binder may, in particular, be a film-forming non-biodegradable binder.
The concentration in the layer of eco-toxic substances, in particular fluorocarbon compounds additives, is preferably less than 200 parts per million.
Structure of the Product According to the Invention
The products according to the invention may have, when completely unfold, a greatest dimension comprised between 15 cm and 180 cm, for example 60 cm and 150 cm.
When the product is a container filter, its greatest dimension may, in particular, be comprised between 15 cm and 60 cm.
The thickness of the gowns, sterilization wraps or sterile fields according to the invention may, in particular, lie in the range 100 μm to 250 μm, preferably 125 μm to 175 μm.
The sterilization wrap may have a density of 0.8 g/cm3 or less.
The sterilization wrap may have at least a portion comprising a softening process pattern, formed on-line or off-line, configured to soften said sterilization wrap, said softening process pattern being, in particular, selected from one of a creped pattern, micro-creped pattern, and an embossing pattern.
The sterilization wrap is preferably a monolayer material.
The sterilization wrap may be provided in a non-sterilized state and may be sterilized after.
The sterilization wrap may, when completely unfold, be of any shape for e.g.: circular, elliptical or polygonal.
The sterilization wrap, when completely unfold, may be of square shape and, in particular, have a length of about 60 cm, 75 cm or 90 cm.
The invention also concerns a sterilized sterile barrier system as per ISO 11607 standard definition comprising a sterilization wrap as described above.
Functional Properties of the Products According to the Invention
The sterilization wrap, container filter and sterile field according to the invention may present at least one, preferably all of, the following features:
The sterilization wrap may comprise less than 0.1% of biocide agents, by dry weight.
The sterilization wrap may be in the sterilized state.
The sterilization wrap may be sterilized and provided in a sterilized packaging following its manufacture.
The sterilization wrap and the field according to the invention may present at least one, preferably all of, the following features:
The sterilization wrap may have a linting value, according to ISO 9073-40, of less than 10, preferably less than 6.
The sterilization wrap may have water penetration resistance values, according to ISO 811, higher than 20 mbar, preferably higher than 40 mbar.
Method of Manufacture of the Sheet
The sheet may be manufactured according to steps a) to d) as described above.
At step a), the furnish may comprise an aqueous solution, according to some embodiments, a coloring agent (e.g., a pigment and/or a dye) may be introduced into the aqueous solution where desired and/or the sheet may be printed or otherwise colored following formation on the wire. For example, where a color match is desired, an appropriate pigment and/or dye (e.g., a blue pigment) may be added to cause the dried sheet to have a desired color. The pigments and/or dyes may be natural and/or synthetic, and combinations thereof, and such pigments may be biodegradable and/or may be inert towards the environment. The pigments may, in particular, be organic or inorganic, and when they are inorganic, they may, in particular, be inert towards the environment.
As such, the sheet according to the invention may, in particular, comprise for example green or blue, inorganic pigments which are inert towards the environment.
Alternatively, the sheet may be void of any coloring agent and may be colored based substantially on the fibers used to manufacture said sheet and other environmental conditions.
At step c), the drying can be carried out at a temperature between about 75° C. and about 200° C.
At step d), sheet may undergo one or more off line or on-line finishing processes. For example one or more softening processes (e.g., mechanical finishing) may be applied to the sheet as desired. Such softening processes may be configured to effect a softening of the sheet, an increase in strength, an increase in breathability, and/or an increase in conformability. Such softening processes may therefore be effective to at least reduce drape values (i.e., increase conformability).
Softening processes may include, for example, mechanical processes such as creping, micro-creping, flexage, embossing, etc. Micro-creping, for example, may act on the web associated with the sheet by compacting it, particularly in the machine direction (MD). Therefore, when exposing to a micro-crepe finishing process, it may be desirable to have a certain percentage of fibers of the web oriented in the machine direction, thereby allowing more fibers to be creped.
According to some embodiments, the finishing processes (e.g., softening) may be configured to form a pattern on and/or within the structure of sheet resulting in, for example, a softening process pattern on and/or within the structure of sheet. Such a pattern may be a visible pattern, semi-visible, or not visible to the naked eye (e.g., microscopic pattern), as desired, and/or combinations thereof. The mechanical finishing processes may be executed on any suitable processor, for example, when micro-creping sheet, a mechanical microcreper may be utilized. According to some embodiments, a Micrex® Microcreper may be implemented to micro-crepe the formed sheets. For example, a microcreper having rigid retarders, and/or comb roll cavity, and/or two rolls cavity, and/or flat blade cavity, or bladeless microcreper may be utilized.
According to some embodiments, coloring agents may be added to provide color to the sheet after the mechanical finishing process, particularly where coloring agents may affect the mechanical finishing process (e.g., depending on sensitivity of a creping machine). For example, a blue pigment may be introduced into the aqueous solution prior to formation on the wire. Additionally, it may be possible to provide designs and/or text, among other things, via printing on the sheet. Alternatively, no coloring agents may be used.
Manufacturing Method of Sterilization Wraps According to the Present Invention
A single layer sheet according to example 4 (see Table 2 below) was manufactured on a Fourdrinier paper machine in the following manner: 89.5% by dry weight of cellulose fibers were suspended in an aqueous medium with 5.1% by dry weight of polylactic acid fibers. A synthetic acrylic binder was added in a concentration of 3.5% by dry weight. A biodegradable binder was added in a concentration of 0.7% by dry weight, a non-biodegradable hydrophobic additive was added in a concentration of 0.3% by dry weight and an additive of unknown degradability was added in a concentration of 0.9% by dry weight. The suspension was dewatered on the wire of the paper machine in order to form the sheet. The sheet was dried at around 120 degrees C. and the resulting sheet had a grammage of approximately 64.1 g/m2.
The sheet was then micro-creped to effect a softening of the sheet. The micro-creping was performed resulting in a conformability value of approximately 75 in the machine direction.
A single layer sheet according to example 5 (see Table 2 below) was manufactured on a Fourdrinier paper machine in the following manner: 86.6% by dry weight of cellulose fibers were suspended in an aqueous medium with 7.4% by dry weight of polylactic acid fibers. A synthetic acrylic binder was also added in a concentration of 3.5% by dry weight. A non-biodegradable hydrophobic additive was added at a concentration of 0.3% by dry weight, an additive of unknown degradability was added at a concentration of 1.5% by dry weight and a biodegradable hinder was added at a concentration of 0.7% by dry weight. The suspension was dewatered on the wire of the paper machine in order to form the sheet. The sheet was dried at around 120 degrees C. and the resulting sheet had a grammage of approximately 63 g/m2.
The sheet was then micro-creped to effect a softening of the sheet. The micro-creping was performed resulting in a conformability value of approximately 79 in the machine direction.
Compositions and Results
Biodegradability Test
The biodegradability of a sterilization wrap consisting in a sheet according to example 5 is tested according to ISO 14855 (2005) method: “Determination of the ultimate aerobic biodegradability and disintegration of plastic materials under controlled composting conditions”.
The test item is prepared by milling said sterilization wrap in particles having a size less than 4 mm.
The reference item is native cellulose powder for thin layer chromatography (cellulose Avicel, Merck).
The test details are reported in table 3.
During the test, the incubation temperature is continuously kept on 58° C.±2° C. and the test lasts 24 days.
The net CO2 production Of the item under consideration (reference item or test item) is obtained by subtracting the CO2 production of the control to the CO2 production of said item.
The biodegradation percentage is the ratio of the net CO2 production of the item under consideration to the original amount of carbon comprised in said item. When the ratio of the biodegradation percentage of the item under consideration to the biodegradation percentage of cellulose is higher than 75%, the item under consideration is regarded as “biodegradable”.
An overview of the evolution of the biodegradation percentage of the different materials is given in
Table 4 illustrates the assessment of biodegradability for example 5.
Throughout the description, including the claims, the term “comprising a” should be understood as being synonymous with “comprising at least one” unless otherwise stated, In addition, any range set forth in the description, including the claims should be understood as including its end value(s) unless otherwise stated. Specific measurement values for described elements should be understood to be within generally accepted manufacturing or industry tolerances, and any use of the terms “substantially” and “approximately” should be understood to mean falling within such generally accepted tolerances. Component ratios throughout the disclosure shall be understood to be by dry weight unless otherwise specified.
Although the present disclosure herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present disclosure as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10290595.7 | Nov 2010 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB2011/054777 | 10/26/2011 | WO | 00 | 7/15/2013 |
| Number | Date | Country | |
|---|---|---|---|
| 61410439 | Nov 2010 | US |
