GB2594110A

GB2594110A - Nonwoven sponges, nonwoven sponge pack and their applications

Info

Publication number: GB2594110A
Application number: GB2017099.9A
Authority: GB
Inventors: C Chan Laurence
Original assignee: Gx Surgical Co Ltd
Current assignee: Gx Surgical Co Ltd
Priority date: 2019-10-28
Filing date: 2020-10-28
Publication date: 2021-10-20
Also published as: GB202017099D0; AU2020260448A1

Abstract

A nonwoven absorbent sponge 10 for wound care and surgical related applications, the sponge includes a single layer of spunlace nonwoven fabric which has a top side with a coarse surface having a three dimensional (3D) texture S11 and a bottom side with a smooth surface S12 . Preferably the coarse surface S11 and smooth surface S12 is formed by spraying high pressure water jets onto a patterned screen which is placed on a web of material fibres. The nonwoven fabric is preferably made with one of or a blend of rayon, viscose, polyester, cotton and/or bamboo fibres. There can be a pack in the form of a sealed pouch 20 within which the nonwoven absorbent sponges 10 are contained. Also provided is a method of increasing the tensile strength of the nonwoven sponge 10 to at least 15 Newton by a step of cross lapping the fibres in a nonwoven fabric manufacturing process or increasing the water jet pressure used for entangling fibre webs in a spunlace process.

Description

Nonwoven Sponges, Nonwoven Sponge Pack And Their Applications

Technical Field

The present invention generally pertains to a single-use, spunlace nonwoven sponge for wound care and/or surgery applications. The present invention also relates to a pack for containing one or more abovementioned sponges and keeping them sterile in an enclosed io environment.

Background

In medical procedures such as general wound care and surgical incision treatments, traditional sponges are commonly used for absorbing blood and body exudates, as well as for cleaning and debriding wounds. Further, it should be noted that "traditional sponges" connotate pure sponges without being impregnated with any medication or other substances whereas "advanced sponges" are generally used to refer to medicated and impregnated sponges. Currently, there are two major types of traditional medical sponges in the marketplace, namely (woven) gauze sponges and nonwoven sponges. Nonwoven sponges are generally made of a spunlace nonwoven fabric comprising rayon, polyester or cotton fibers. Comparatively speaking, gauze sponges are much more commonly used than nonwoven gauges because of historical reasons and their suitability for use in both wound care and surgery related applications. Particularly in surgery related applications, surgical sponges are required to possess relatively high strength and tear-resistance which regular nonwoven sponges lack.

On one hand, sponges made of gauze fabric offer the major advantages of: (i) absorbing fluids from wounds with a high amount of blood and/or body exudates; (ii) having a generally coarse surface (due to the nature of the gauze 5 threads) for cleaning and debriding wounds; and (iii) having a relatively high tensile strength which means a high level of breaking resistance during use.

On the other hand, gauze sponges do have some major disadvantages including: (i) an excessively high level of lint, loose threads and other contaminations are commonly found in gauze fabrics because of their open edges and the high frequency of human contact with the sponges during the manufacturing process; (ii) a relatively low absorbency due to its open mesh, which means a high 15 number of gauze sponges are often required to absorb the blood and other exudates: and (iii) high manufacturing costs which continues to trend upward due to the high labor content coupled with rapidly rising wage levels in key countries where most of the gauze sponges in the world are made.

As for regular nonwoven sponges, they were introduced into the medical field in the late 1980's by Johnson & Johnson (J&J) in USA with an intention to replace gauze sponges. Such nonwoven sponges are made of spunlace nonwoven materials comprising a blend of rayon/polyester in a 70/30 weight ratio. It should be noted that the J&J style of nonwoven sponges is generally known as the regular nonwoven type. Due to its simple and highly automated manufacturing process, nonwoven spunlace fabric is less costly than woven fabric. In addition, nonwoven sponges have the following advantages over gauze sponges: (i) lower level of linting and no loose threads: (ii) non-adherence to wounds: and (iii) much higher absorbency. However, regular nonwoven sponges generally have a relatively low tensile strength in the cross direction of the fabric, which leads to a relatively low tear-strength and therefore are not suitable for surgical related applications. In addition, all of the medical nonwoven sponges that are readily available in the market today have a lightly textured and relatively smooth surface. These textures are typically formed by the application of a screen (generally made of stainless steel) with a crisscross pattern (simulating the crisscross pattern of the gauze io threads of a gauze sponge) during the spunlace nonwoven manufacturing process. In the last step of the production line, the screen is placed on a wetted fiber bed before high pressure water spraying takes place. This creates the nonwoven fabric by entangling the fibers and results in the crisscross pattern at the same time. However, such patterns are 2-dimensional (2D) in nature and generally considered not coarse enough for wound debridennent. As such, regular nonwoven sponges are only used for low-end medical applications.

Circa 2008, there was an attempt to use spunlace nonwoven fabric made with cotton fiber having a relatively high tensile strength to make nonwoven cotton sponges intended for surgical related applications. However, usage of these nonwoven cotton sponges in the medical field are still very limited nowadays because of their relatively high stiffness and higher cost compared to the traditional gauze sponges. Further, nonwoven cotton sponges have a shortcoming of having a lightly textured surface whose coarseness is much lower than that of gauze sponges. Therefore, nonwoven cotton sponges are considered not suitable for wound cleaning and debridement which require a coarse surface.

In light of the above background, it is an object of the present invention to provide a single nonwoven sponge which possesses at least some of the favorable properties and/or characteristics of both the traditional gauze sponges and the regular nonwoven sponges, or which may overcome or at least ameliorate the above shortcomings or which will at least provide a useful choice.

Brief Description of the Invention

According to one aspect of the present invention, there is provided a nonwoven absorbent sponge for medical use, the sponge including a single layer of spunlace nonwoven fabric which has a top side with a coarse surface having a three dimensional (3D) texture and a bottom side with a smooth surface.

In a preferred embodiment, the 3D textured top side and the smooth surface of the bottom side are formed by spraying high pressure water jets onto a patterned screen which is placed on a web of material fibers.

Preferably, the nonwoven fabric is made with one of or a blend of the following types of fibers: rayon, viscose, polyester, cotton and bamboo fibers.

Preferably, the nonwoven fabric has a fabric weight ranging from 30 gram 25 per square meter (gsm) to 130 gsm and a tensile strength not lower than 15 Newton in both warp and weft directions of the fabric.

It is preferred that the 3D textured top side includes an array of protrusions. Preferably, the array of protrusions is arranged to form a predesigned pattern. Even more preferably, each of the protrusions is substantially in the shape of one of the following: hemisphere, pyramid, semioval, tetrahedron, cube, rectangular cuboid and octahedron.

Preferably, each of the protrusions has a height which ranges from 0.1mm to 1.0 mm. More preferably, each of the protrusions has a width ranging from 2cm to 100cnn and a length ranging from 2cm to 200cm.

According to a second aspect of the present invention, there is provided a io pack being in the form of a sealed pouch within which the one or more nonwoven absorbent sponges are contained.

According to a third aspect of the present invention, there is provided a method of increasing the tensile strength of the nonwoven sponge as defined above to at least 15 Newton, which involves a step of cross lapping the fibers in a nonwoven fabric manufacturing process or increasing the water jet pressure used for entangling fiber webs in a spunlace process.

Brief Description of the Drawings

The present invention may be better understood from the following non-limiting description of the preferred embodiments, in which: Figure 1 is a perspective view of a nonwoven sponge in accordance with a 25 preferred embodiment of the present invention illustrating the nonwoven sponge in an unfolded state with a corner folded up displaying the bottom side; and Figure 2 is a cross-sectional view of a pack carrying a stack of nonwoven sponges.

Detailed Description of the Drawings

It should be noted that there are two major requirements for improving the properties of a nonwoven sponge, namely (i) enhancing the tear-resistance of the nonwoven sponge by increasing the tensile strength of the nonwoven sponge to at least 15 Newton, which can be achieved by cross lapping the fiber webs in the nonwoven fabric manufacturing process or by increasing the water jet pressure used for entangling the fiber webs in the spunlace process; and (ii) increasing the surface coarseness of the nonwoven fabric to such that the level of coarseness is close to that of a gauze sponge. A coarser surface in combination with a high tensile strength means that the nonwoven sponge of the present invention is capable of preserving its favorable properties rendering it fit to be used for various kinds of wound treatment and in surgery related applications.

Referring to Figures 1 and 2, an exemplary embodiment of a nonwoven sponge 10 is illustrated. The nonwoven sponge 10, a pack carrying a stack of the nonwoven sponges and the intended applications of the nonwoven sponge 10 will now be described in detail.

As shown in Figure 1, the nonwoven sponge 10 has one single layer of spunlace nonwoven fabric. The nonwoven sponge 10 has a coarse, three dimensional (3D) textured top surface S11. In contrast, the bottom side has a smooth surface S12. In other words, the top surface S11 of the nonwoven sponge 10 has a 3D texture which leads to an increase of the coarseness of the surface S11. As such, the top surface S11 is a coarse surface whereas the bottom surface S12 without the 3D texture is a smooth surface.

It will be appreciated that while the coarse top surface S11 is capable of enhancing the cleaning and debridement capability of the nonwoven sponge 10, the flat and smooth bottom surface S12 is very suitable for treating patients with sensitive wounds and skins. In essence, the nonwoven sponge 10 possesses a combination of the most favorable io properties of the traditional gauze sponge (with the 3D textured top surface S11 and a high tear resistance) and the regular nonwoven sponge (with a high absorbency, low level of linting, and high levels of smoothness and anti-adherence). Due to such favorable properties or characteristics, the sponge 10 can be used for treating all kinds of wounds with a higher level of effectiveness and improved safety compared to the traditional gauze and regular nonwoven sponges in wound care and surgery related applications.

In order to provide the nonwoven sponge 10 with a high level of coarseness on a consistent basis, a 3D (Dimensional) texture is imparted on the top surface S11 of the nonwoven sponge 10. The 3D texture is preferred to be formed in-situ in the course of the spunlace nonwoven fabric manufacturing process. In such a process, a screen generally made of stainless steel with a predesigned pattern is placed on a wetted fiber web (this is actually the last stage of the nonwoven fabric manufacturing process). When high pressure jets are imparted onto the fibers to cause entanglement of the fibers and forming of the nonwoven fabric, protrusions of the fibers which create the 3D textured pattern on the top surface S11 as well as the smooth bottom surface S12 are also formed at the same time. The spunlace process for making the 3D pattern is well-controlled and reliable provided that a high quality spunlace nonwoven line is used.

For the purpose of making the nonwoven sponge 10 with a 3D textured top surface S11 and a smooth bottom surface S12, the following fibers can be used individually or in a mixed blend: Rayon (aka viscose), polyester, cotton and bamboo fibers. Generally speaking, Rayon is the preferred material over the others because of its softness, high water absorbency, eco-friendliness and lower material cost. In this embodiment, the fabric io weight of the nonwoven fabric for making the sponge ranges from 30 gram per square meter (gsm) to 130 gsm. The tensile strength of the nonwoven fabric in both the warp and weft directions of the fabric needs to be not lower than 15 Newton, as tested by a 5 cm x 10 cm specimen cut out from the fabric with a crosshead speed of a tensile tester operating at about 20 cm per minute. The 3D textured surface has an array of protrusions which forms a predetermined pattern in the present embodiment. Also, in the present embodiment, each of the protrusions takes the shape of a hemisphere. It should however be noted that the protrusions on the 3D textured surface may be in the shape of one of the following: hemisphere, pyramid, semioval, tetrahedron, cube, rectangular cuboid and octahedron. The height of the protrusions on the 3D textured surface is preferred to be in the range of 0.1mm to 1.0 mm. In an unfolded state, the sponge 10 has a width which ranges from 2cm to 100cm and a length which ranges from 2cm to 200cm.

As illustrated in Figure 2, one or a pile of multiple nonwoven sponges 10 may be sterilized and placed in a sealed pouch or tray 20 to form a sterile pack. With the different surfaces S11 and S12, the sponge 10 is suitable for use in both wound care and/or surgery related applications.

It should be noted that the significant factors for generating a nonwoven fabric with a pronounced 3D textured surface include the following: (1) The weight of the fabric which is generally expressed in gram per square meter (gsm). The 3D surface structure basically consists of numerous protrusions of nonwoven fibers which are squeezed out from the nonwoven substrate by water jets during the formation of the 3D nonwoven fabric. It is important to note that if and when the nonwoven fabric is made out of a light weight material with a low gsm, there are not many fibers that can be squeezed upwardly to form the protrusions which in turn collectively formthe3D surface pattern on the top side of the nonwoven fabric. In general, the fabric weight of the nonwoven fabric must have a minimum of 30 gsm in order for the formation of a functional 3D surface structure; (2) The height of the protrusion extending from the surrounding substrate material-The coarseness level is dependent on the height of the 15 protrusions which form the 3D pattern. In general, higher and more pronounced protrusions would result in a higher coarseness level; (3) The fibers used for making the nonwoven fabric -The coarseness level of the nonwoven fabric is dependent on the type of fibers used to make the nonwoven fabric. In general, a 3D textured surface with a desired level of coarseness is easier to achieve with a Rayon based spunlace fabric, most probably due to the relatively high flexibility of its fibers compared to other types of fibers.

(4) The pressure level of the water jets for entangling the nonwoven web -The pressure level is preferred to be set at or near the highest level for the spunlace production line so as to cause the protrusions to be squeezed outwardly for the formation of the 3D pattern and simultaneously enable fiber entanglement for the formation of the nonwoven fabric.

(5) The tensile strength of the fabric-In order for the 3D textured surface to have a high level of coarseness, the nonwoven substrate must have some strength and cannot be too soft and weak. The tensile strength of the nonwoven fabric in the present embodiment should not be lower than 15 Newton, as tested by a 5 cm x 10 cm specimen cut out from the fabric with a crosshead speed of a tensile tester operating at about 20 cm per minute.

(6) Cross lapping of the fabric -In order to achieve a higher tensile strength for the nonwoven fabric, cross lapping of the fibers is generally preferred over straight lapping when forming the spunlace nonwoven fabric.

(7) 3D pattern of the textured surface -the 3D, highly textured surface is preferred to have a repeating pattern of nonwoven material being in a predesigned shape and protruding from the substrate of the fabric surrounding the protrusions. The height of each of the protrusions 101 is preferred to have a height of 0.1mm to 1.0 mm from the fabric. The protrusions may take the shape of any of the following: hemisphere, pyramid, semioval, tetrahedron, cube, rectangular cuboid and octahedron.

As mentioned above, in addition to the creation of the 3D textured surface on the top layer of the nonwoven fabric, it is equally important to form a smooth surface on the bottom side of the spunlace nonwoven fabric. It should be noted that the bottom surface S12 of the fabric is formed at the same time as the 3D top surface S11 during the spunlace nonwoven fabric manufacturing process. To this end, the significant factors are as follows: (1) The weight of the fabric which is generally expressed in gram per square meter (gsm). If the nonwoven fabric is made out of a light weight material with a low gsm, forming of the protrusions on the top surface would create depressions in the bottom surface 512 of the fabric. It is therefore preferred that the nonwoven fabric has a fabric weight of 30 gsm at the bare minimum in order to facilitate formation of a flat and smooth bottom surface S12 in conjunction with the top 3D surface structure.

(2) The fibers used for making the nonwoven fabric -Among all the commonly used fibers such as cotton and polyester, Rayon is found to be the best fiber material for the purpose of simultaneously generating the flat and smooth bottom surface S12 and the 3D highly textured top surface S 1 1.

(3) The pressure level of the water jets for entangling the nonwoven web -In order to create a flat and smooth bottom surface S12, the nonwoven fibers must be pressed firmly onto the conveyer belt in the spunlace production line. To this end, it is preferred to have the pressure level set at io or near the highest level for the spunlace production line.

(4) 3D pattern of the textured surface -It is noted that the amount of protrusions for the 3D, highly textured surface has a certain effect on the flatness and smoothness of the bottom surface of the spunlace nonwoven fabric. Pronounced protrusions especially created with lower weight fabric would likely lead to an array of depressions on the bottom surface S12. As such, the height of the protrusions should not be higher than 1nnm even for heavily gaged nonwoven fabric.

It should be noted that the sponge 10 of the present invention made with the 3D textured nonwoven fabric is intended to still retain the typical advantages offered by regular nonwoven sponges, namely (a) high water absorption rate, (b) low lint level and (c) soft feel. As for (a) the absorption rate, the water absorption ability of sponges made of a 3D textured nonwoven fabric has been compared with that of sponges made of a regular 2D textured nonwoven fabric. The water absorption test was conducted by measuring the weight of a dry sponge (W1). The dry sponge was then immersed in water for at least 10 seconds before being removed from the water to drip for 30 seconds (or until water droplets from the wetted sponge has stopped). The weight of the wetted sponge (W2) is then measured. The rate of water absorption is equal to (W2 -W1)/W1. It is noteworthy that water absorption studies shows that the water absorption rate of the nonwoven sponges is not really affected by the 3D textured surface formations and is significantly higher than that of the woven cotton gauze sponges. As to (b) the lint level, a rubbing test of the dry sponge fabric on a black glass panel has been conducted. In such a test, the fabric is rubbed onto the panel for 30 seconds. Any loose lint from the sponge can easily be observed on the black glass panel afterwards. The test results show that there is no loose lint coming off the 3D textured nonwoven sponges. In contrast, the same test was done with a gauze sponge and a significant amount of loose lint was found on the black glass panel. As for (c) the soft feel, the softness of the 3D textured nonwoven fabric has been compared with that of the regular 2D textured nonwoven fabric. It has been concluded that there is no noticeable difference between the two nonwoven fabrics in terms of their softness. However, it has been found that the 3D textured nonwoven fabric feels coarser than the 2D textured nonwoven fabric because of the protrusion pattern on the surface.

Some major tests and analytical studies have been conducted on the nonwoven sponge 10 which comprises a 3D textured surface in the top side S11 and a smooth surface at the bottom side S12 of the nonwoven fabric. The results from these tests have demonstrated the effectiveness of the nonwoven sponge 10 with respect to the objectives of the present invention.

Study 1. Coarseness Level of Existing Sponges Study Result: Coarseness level for regular and 2D nonwoven fabric is well below gauze.

Regular Newer Style of Traditional Nonwoven Nonwoven Gauze Fabric Fabric (J&J Fabric Style) Textured Surface 2D 2D 2D Coarseness Level 1 3 5 Note: Coarseness Level: 1 (Lowest) 3 (Moderate) 5 (Highest) Study 2. Coarseness Level of 3D Nonwoven Sponges vs. Fabric Weight.

Study Result: Coarseness level for 3D nonwoven Rayon fabric is similar to gauze 3D 3D 3D Typical Nonwoven Nonwoven Nonwoven Gauze Fabric Fabric Fabric Fabric (38 gsm) (60 gsm) (100 gsm) Textured Surface 3D 3D 3D 2D Top surface Coarseness Level 3 4 5 5 Height of Protrusion 1 3 5 0 Notes: (1) Coarseness Level: 1 (Lowest) 3 (Moderate) 5 (Highest) (2) Protrusions of 3D Texture: 1 (Lowest) 3 (Moderate) 5 (Highest) Study 3. Coarseness Level of 3D Nonwoven Sponges Made of Different Materials Study Result: Coarseness for Rayon is higher than nonwoven fabric made of others.

3D 3D Nonwoven 3D Typical Nonwoven Rayon/Polyester Nonwoven Gauze Rayon (100 gsm) Cotton Fabric (100 gsm) (100 gsm) Textured Surface 3D 3D 3D 2D Top surface Coarseness Level 5 3 3 5 Note: Coarseness Level: 1 (Lowest) 3 (Moderate) 5 (Highest) Study 4. Properties of 3D Nonwoven Sponges with Various Coarseness Levels.

Study Result: 3D nonwoven Rayon fabric retaining the typical nonwoven properties.

3D 3D 3D Typical Nonwoven Nonwoven Nonwoven Gauze Fabric Fabric Fabric Fabric (38 gsm) (60 gsm) (100 gsm) Textured Surface 3D 3D 3D 2D Top surface Coarseness Level 3 4 5 5 Water Absorption Rate (gm/gm) 9 9 9 4 Lint Level No No No High Softness Feel Soft Soft Soft Soft

S

Notes: Coarseness Level: 1 (Lowest) 3 (Moderate) 5 (Highest) Study 5. Smoothness for Bottom Surface for Various 3D Nonwoven Sponges of Various Fabric Weights Study Results: Bottom surface for 3D nonwoven Rayon fabric is much smoother than gauze.

S

3D 3D 3D Typical Nonwoven Nonwoven Nonwoven Gauze Fabric Fabric Fabric Fabric (38 gsm) (60 gsm) (100 gsm) Textured Surface 3D 3D 3D 2D Top surface Coarseness Level 3 4 5 5 Bottom surface Smoothness Level 3 4 5 1 Notes: (1) Coarseness Level: 1 (Lowest) 3 (Moderate) 5 (Highest) (2) Smoothness Level: 1 (Lowest) 3 (Moderate) 5 (Highest) Turning now to Figure 2, a preferred embodiment of a pack 20 carrying a stack of the nonwoven sponges 10 is shown. In this embodiment, the pack is in the form of a sealed pouch 20 containing multiple pieces of nonwoven sponges 10. The sealed pouch 20 can be used for carrying the sponges 10 in a sterile environment preventing the sponges 10 from being contaminated or for other purposes.

In addition, it should be noted that the nonwoven sponge 10 of the present invention is suitable for use in a much wider range of wound care and surgery related applications than the traditional gauze sponges and the regular nonwoven sponges. As for wound care applications, the sponge 10 can be used for debridement, prepping, cleaning, cushioning, treatment of sensitive wounds and other wound care related applications. As for surgical applications, the sponge 10 can be used for absorption of blood and other body exudates, wiping, cushioning, protection of organs, and other surgery related applications.

Now that a preferred embodiment of the present invention has been described in some detail, it will be apparent to a skilled person in the art that the 3D nonwoven sponge of the present invention with its unique characteristics may offer at least the advantages of being more versatile and effective than all of the conventional sponges for wound care and/or in surgery applications. While the 3D nonwoven sponge of the present invention has been described in detail using the preferred or an exemplary embodiment for illustration purposes, those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. All such variations and modifications are to be considered within the scope and spirit of the present invention the nature of which is to be determined from the foregoing description. Also, any equivalent structural transformation made by using the description of the present invention and the attached drawings, or direct / indirect applications in other related technical fields under the concept of the present invention, should be considered to be captured by the patent protection scope of the present invention.

Claims

Claims: 1. A nonwoven absorbent sponge for wound care and surgical related applications, the sponge including a single layer of spunlace nonwoven 5 fabric which has a top side with a coarse surface having a three dimensional (3D) texture and a bottom side with a smooth surface.
2. The nonwoven absorbent sponges according to Claim 1, wherein the 3D textured top side and the smooth surface of the bottom side are formed io by spraying high pressure water jets onto a patterned screen which is placed on a web of material fibers.
3. The nonwoven absorbent sponges according to either Claim 1 or 2, wherein the nonwoven fabric is made with one of or a blend of the 15 following types of fibers: rayon, viscose, polyester, cotton and bamboo fibers.
4. The nonwoven absorbent sponge according to any one of the preceding claims, wherein the nonwoven fabric has a fabric weight ranging 20 from 30 gram per square meter (gsm) to 130 gsm and a tensile strength not lower than 15 Newton in both warp and weft directions of the fabric.
5. The nonwoven absorbent sponge according to any one of claims 2 to 4, wherein the 3D textured top side includes an array of protrusions.
6. The nonwoven absorbent sponge according to claim 5, wherein the array of protrusions is arranged to form a predesigned pattern.
7. The nonwoven absorbent sponge according to either claim 5 or 6, wherein each of the protrusions is substantially in the shape of one of the following: hemisphere, pyramid, semioval, tetrahedron, cube, rectangular cuboid and octahedron.
8. The nonwoven absorbent sponge according to any one of claim 5 to 7, wherein each of the protrusions has a height which ranges from 0.1mm to 1.0mm.
9. The nonwoven absorbent sponge according to any one of the preceding claims having a width ranging from 2cm to 100cm and a length ranging from 2cm to 200cm.
10. A pack carrying one or more nonwoven absorbent sponges of any 15 one of the preceding claims, the pack being in the form of a sealed pouch within which the one or more nonwoven absorbent sponges are contained.
11. A method of increasing the tensile strength of the nonwoven sponge of any one of the preceding claims to at least 15 Newton, the method involving a step of cross lapping the fibers in a nonwoven fabric manufacturing process or increasing the water jet pressure used for entangling fiber webs in a spunlace process.