Layered porous wound dressing, manufacturing process thereof, and useful article

Abstract

The present invention relates to a novel wound dressing design. In particular, the present invention relates to a wound dressing that incorporates multiple distinct layers, each providing a useful function and combining to provide a new approach to treating various types of wounds. These layers promote moist healing, manage exudate, and provide ease of use and patient comfort. In a preferred embodiment, the novel dressing comprises a thin layer of gel continuously coated onto a thin film material laminated to a perforated mesh. Preferably, the gel-coated thin film material is fenestrated or perforated. This structure improves the fixation of the dressing and provides a semi-occlusive wound environment while simultaneously managing large amounts of exudate.

Description

Technical Field

[0001] The present invention relates to the design of a novel wound dressing. In particular, the present invention relates to a wound dressing incorporating a plurality of different layers that each provide a useful function and, when combined, provide new ways to treat various types of wounds. It provides moist healing, treatment of exudate, ease of use and patient comfort.

Background Art

[0002] In the field of wound treatment, there are several categories of commonly used dressings, each with its own advantages and disadvantages. Each of them is presented according to the condition of the wound and the user's preference. For example, conventional gauze is inexpensive and widely available, but as the eschar forms on the wound bed and healing progresses, it tends to integrate with the wound. As a result, changing the dressing is painful and may have a reverse effect. Hydrogel and hydrocolloid dressings are soft and gentle on the wound, but they are bulky and may accumulate excessive moisture due to insufficient treatment of exudate, causing maceration of the tissue. Thin semi-occlusive polymer films coated with a pressure-sensitive adhesive (PSA) are readily available and provide a moist healing environment that can handle a certain amount of exudate. A common example of this type of dressing is a polyurethane film coated with an acrylic PSA. These dressings are easy to apply and maintain, but they may adhere easily to adjacent tissues, become difficult to remove, or cause inflammation due to the PSA.

[0003] Woven fabrics, non-woven meshes, and various types of perforated films and nets are also used as wound dressings of various designs. This mesh functions as a wound contact surface and / or as a mechanical reinforcement mechanism to make handling easier.

[0004] The impregnated mesh covering material can use various porous materials, such as woven fabric monofilament structures, non-woven spunlace webs, extruded perforated materials ("scrim"), knitted fiber products, and even 3D printed structures, etc. (not limited to these), and these are collectively called "porous meshes". This type of covering material is easy to handle and fix. However, although porosity is effective for treating exudate, integration with the wound bed and, in extreme cases, wound drying can be troublesome problems.

[0005] In recent years, silicone has been increasingly used in wound treatment applications, especially because it can "gently" adhere to the skin. For example, there are those in which various porous substrates are impregnated with silicone or coated with a thin film.

[0006] Biomed Sciences in Allentown, Pennsylvania, USA, manufactures and sells the "Rylon (registered trademark)" brand of wound covering materials, which are woven polyester monofilament meshes impregnated or coated on one or both sides with an adhesive silicone gel (respectively "Rylon-1" or "Rylon-2"). Since the gel is partially impregnated into the mesh, some of the holes remain open for treating exudate. Furthermore, this mesh has a reinforcement mechanism sufficient to hold surgical staples if necessary.

[0007] These products are easy to handle and can treat a large amount of exudate, but generally cannot provide a semi-sealed environment for moist healing.

[0008] Furthermore, the prior art includes silicone-coated thin films that provide a semi-sealed environment and a non-adherent wound contact surface. While these types of coatings promote moist healing, they tend to wrinkle and slip on the wound, presenting problems with stability and fixation. As an example of such a coating, U.S. Patent No. 4,832,009, which is incorporated herein by reference, discloses a coating made from an interpenetrating polymer network (IPN) of polytetrafluoroethylene ("PTFE") and silicone, which is currently marketed by Bio-Med Sciences, Inc. as "Silon-TSR® Temporary Skin Replacement." An IPN is a type of polymer / polymer composite in which each polymer forms a continuous matrix that penetrates the other.

[0009] Similar to wound dressings, the types of wounds vary widely. Wounds are classified as chronic or acute. Examples of chronic wounds include venous stasis ulcers, pressure ulcers, and diabetic ulcers. Examples of acute wounds include burns, donor sites for skin grafts, recipient sites for skin grafts, and abrasions. Wounds can also be extensive or linear in surface area. Extensive wounds such as burns are particularly problematic compared to linear wounds such as incisions or lacerations. In linear wounds, the edges of the tissue are close together, so fewer wounds need to be closed, and the tape, suture, staple, etc. can directly contact each side of the damaged tissue. In extensive wounds, healing needs to occur from the wound bed upwards. In deep wounds where the dermis is damaged or destroyed, a skin graft is required. Whether or not a graft is performed, extensive healing is slow and painful.

[0010] The functions required for the proper treatment of a wound dressing not only vary depending on the type of wound but are also greatly affected by the body part. This problem is particularly difficult in skin graft sites on the patient's back or buttocks, where the dressing can easily shift due to normal movement or contact with bedding. In the case of the graft recipient site, the graft itself may also become dislodged. Similarly, chronic wounds tend to produce a large amount of exudate, presenting the problem that semi-sealing films cannot often be used. Pressure ulcers in the sacral region are particularly troublesome.

[0011] Even for the same wound, different dressing materials may be required at different stages of the healing process.

[0012] Venous stasis ulcers produce a large amount of exudate in the initial stage of healing. For such wounds, hydrocolloid dressings with high absorbency are often used. However, when such types of wounds heal, the fragile epithelium is easily damaged during dressing replacement. Therefore, in the latter half of the healing process, a non - adherent dressing can be used instead.

[0013] Infections are always a threat in wounds of all conditions and can cause serious complications. Therefore, various antibacterial agents are used in combination at the scene or incorporated into a variety of wound dressings. Commonly used antibacterial agents include bacitracin, neomycin, polymyxin, etc. Furthermore, silver - based compounds and dressings containing silver - based compounds have become common in wound treatment. Silver - based compounds containing a high atomic state of silver (Ag2 +, Ag3 +) are preferred. Additionally, non - eluting polymer antibacterial agents composed of polycoat salts such as 3 - methoxysilylpropyl dimethyloctadecylammonium chloride are used to inhibit the formation of microbial colonies.

[0014] For the above reasons, there is no universal dressing material for all types of wounds, situations, and stages of healing.

[0015] In the field of polymer films, in addition to the aforementioned polyurethanes, materials including copolymers and composites such as polyethylene, polyester, polycaprolactone, vinyl, and other materials (collectively referred to as "polymer films") are used. These polymer films may or may not be porous or microporous. Examples of such polymer films are described in U.S. Patent No. 4,945,125, which is incorporated herein by reference, and which discloses a microporous polymer IPN membrane of PTFE and silicone, and is of particular interest for the present invention. In this specification, the terms "film" and "membrane" are used interchangeably, and the term "web" is affixed to a long film or membrane produced in a continuous process for manufacturing a roll product of such a material.

[0016] In the field of adhesives, there are numerous chemical systems such as acrylic, hydrogel, silicone, etc. (collectively referred to as "surface adhesives"). For clarity, surface adhesives are not to be confused with contact adhesives such as cyanoacrylate adhesives.

[0017] Even in the field of silicone chemistry, numerous systems are known in the art. Of particular interest in the present invention are polysiloxane formulations, particularly polydimethylsiloxane - based systems using platinum catalysts common in the medical field. Generally, these formulations are two - component systems where one component contains a cross - linker and the other contains a catalyst. The two components are made liquid and mixed together. Through cross - linking between polymer chains (usually promoted by heat), the polysiloxane cures or vulcanizes to form a cohesive solid with various properties ranging from a hard elastomer to a soft and flexible gel, mainly depending on the cross - link density. Elastomers tend to have a non - sticky surface and high durometer values, while gels have low durometer values and tend to be adhesive or tacky to contact. Such formulations with low cross - link density are useful in the field of wound treatment as semi - adherent "gentle adhesives" that are sticky to the skin or wound surface but do not adhere so strongly as to damage the wound when peeled off. In the present invention, such types of polymer formulations (regardless of whether they are silicone - based) will be referred to as "gels". Examples of suitable elastomeric silicones include product code MDX4 - 4210 from Dow Corning (Midland, Michigan). Examples of suitable silicone gels include product code 7 - 9700 from Dow Corning.

Summary of the Invention

[0018] To improve upon the prior art, the inventor has developed a coating material with a unique laminated design that reduces the problems of silicone thin films and silicone - impregnated meshes and takes advantage of their strengths.

[0019] In a preferred embodiment, the novel invention's coating material is formed by laminating a silicone-impregnated porous mesh, preferably a woven fabric mesh coated on one side (in this case, it is not necessary to coat the second side), preferably including a windowed or perforated IPN / gel film. For the purposes of the present invention, the terms "partially impregnated" and "coated" can be used interchangeably to describe attaching a polymer to a porous mesh, whether the polymer actually penetrates the mesh or simply binds to its surface. Preferably, the IPN / gel film is windowed or perforated and includes a thin layer of silicone gel continuously coated on a silicone / PTFE IPN membrane. (Here, the terms "windowed" and "perforated" may be used interchangeably.) Depending on the shape and relative frequency of the hole patterns in each layer, open holes are formed in a defined pattern across the entire coating material. This structure not only improves operability and fixity but also provides a semi-sealed wound environment capable of handling a large amount of exudate.

[0020] By applying the new coating material with the gel side of the IPN / gel film against the wound, the advantages of the non-adhesiveness and non-integration of the Silon–TSR coating material can be retained. However, at the same time, the excellent operability and fixity of the Rylon coating material are maintained as they are.

[0021] The IPN / gel material is provided with windows and perforations, and the perforated mesh is substantially open. This allows exudate from the wound to move freely through the covering material and optionally to a secondary covering material. By controlling the shape and design of the windows of the IPN / gel film with respect to the pores and holes of the impregnated mesh, the balance between moist healing and exudate management can be adjusted. Consider that even if the hole areas are the same, the wound treatment function will be different depending on whether there are many small holes or few large holes. By varying the window and hole patterns of the layers of the covering material of the present invention, the ability to design numerous clinically important covering material designs is obtained. The window and hole combinations are added by providing aligned openings and a path for exudate to flow. Conversely, if the moisture remains unaligned, it is subtracted. Due to the nature of repeating patterns, a certain harmonious beat design is created. By finely tuning one pattern, the overall pattern of the openings through the covering material is significantly affected. The relative spacing between the windows and holes does not require aligning the two main layers of the covering material unless one is an integer multiple of the other. In other words, if the spacing between the holes in the wound contact layer and the holes in the mesh layer is exactly the same, the two layers need to be accurately positioned so that the openings through the combined layers are maintained. When the hole and hole spacing is other than an integer multiple, repeating the pattern multiple times will cause the holes to align. In this way, the covering material can be designed to allow the required flow rate of exudate to pass through (e.g., low, medium, high).

[0022] Thus, in the present invention, the relative shape of the film windows and mesh holes can adjust exudate management and moist healing characteristics, and also provide non - adhesiveness and ease of handling.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0024] Figure 1 is a cross-sectional view showing a preferred embodiment of the present invention. As shown in Figure 1, the covering material (60) of the present invention includes a semi-sealing polymer film layer (10) (such as a silicone / PTFE IPN film) coated with a silicone gel (20) having adhesiveness on one surface and adhered to the silicone-coated surface (40) of a perforated mesh layer (50) on the other surface. The silicone gel (20) provides a gently adhesive wound contact surface (30) for the wound dressing (60). The wound contact surface (30) of the dressing (60) faces the wound and contacts the wound when the dressing (60) is applied to the wound dressing site, and the surface (55) of the perforated mesh layer (50) faces the opposite direction to the wound dressing site when the dressing (60) is applied to the wound dressing site. Due to the gently adhesive property of the silicone gel (20), the wound dressing (60) can be easily peeled off from the wound when desired without the wound contact surface (30) integrating with the wound.

[0025] Figure 2a is a plan view of the covering material (60) of the present invention as seen from the side contacting the wound, showing a preferred window or perforation pattern. The window (70) is cut into the IPN / gel film but not into the perforated mesh.

[0026] Figures 2b, 2c, and 2d are plan views of the covering material (60) of the present invention as seen from the side contacting the wound, showing alternative window or perforation patterns. In addition to the patterns shown in Figures 2a, 2b, 2c, and 2d, many variations of windows and perforations are conceivable. It should be noted that since the tension applied to the film layer downstream of the window forming process may affect the final shape, the final shape and dimensions of the openings formed by the window forming tool may not exactly match the dimensions of the tool design. For example, a slit-shaped window may become an oval hole if tension is applied perpendicular to the slit during subsequent processing.

[0027] Figure 3a is a plan view of a perforated woven mesh material suitable for use in the perforated mesh layer (50) of the present invention. The monofilaments (80) form an aperture structure (90). Figure 3b is a plan view of the perforated woven mesh shown in Figure 3a in a state where it is partially coated with silicone (110) leaving an opening (95) in the perforated mesh.

[0028] Figure 4 is a photographic plan view of the coating material (60) of the present invention as viewed from the side of the coating material (60) facing the wound dressing site when the coating material (60) of the present invention is applied to the wound dressing site. The perforated woven mesh (50) is partially impregnated with silicone (110) so as to maintain the apertures (95) of the mesh (50) in an at least partially open state, and the window pattern (70) of the IPN / gel film (15) is present (not visible in the image). The opening formed by the window pattern is defined by the edge of the IPG / gel film defined by the circumscribed points 130 (barely visible in the image). It should be noted that due to the high transparency of the INP / gel film (15), it is difficult to visualize the opening defined by the IPN / gel (15) and the circumscribed points (130). In this way, the window holes of the IPN / gel film (15) leave an opening (140) that completely penetrates the coating material. In other words, when the window holes defined by the circumscribed points (130) are aligned with the holes (95), a path (140) for the movement of exudate is formed. Everywhere else is blocked by the surface (30) of the IPN / gel film 15.

[0029] Figure 5a is a schematic diagram showing a preferred manufacturing process used to produce a web (280) of an IPN / gel film (15) on a polypropylene-coated paper carrier substrate (150a) of the present invention. The web of the PTFE / silicone IPN (10) on the carrier substrate (150a) is drawn from a roll (160a) and passed over a roller (170). The IPN on the carrier substrate (150a) passes through a reservoir of uncured liquid silicone (180a), and an adjustable blade "knife" (190) is set to meter out excess liquid silicone (180a) leaving a silicone gel (200a) of a desired thickness on the IPN (10) on the carrier substrate (150a). Preferably, but optionally, the uncured liquid silicone (180a) may contain an antibacterial substance such as 3 wt% of a non-leaching polycoat antibacterial agent (3-trihydroxysilylpropyl dimethyloctadecylammonium chloride) or 3 wt% of a silver oxide salt. Next, the uncured gel (20) on the IPN (10) and the carrier substrate (150a) are combined and the resulting structure (200a) is passed through a tunnel oven (230) to apply heat and effect cross-linking of the silicone, forming a web (280) of the IPN / gel film (15) on the carrier substrate (150a). The web (280) of the IPN / gel film (15) on the carrier substrate (150a) is wound onto a master roll (290).

[0030] Figure 5b is a schematic diagram showing a preferred manufacturing process used to produce a web (340) of a porous mesh material (45) that is at least partially impregnated with silicone (i.e., a web of a porous mesh material (50) having a silicone-coated surface (40) that is at least partially impregnated with silicone) of the present invention. The polypropylene-coated paper carrier substrate (150b) is drawn from a roll (160b) and passed over a roller (170). The carrier substrate (150b) passes through a reservoir of uncured liquid silicone (180b), and an adjustable blade "knife" (190) is set to meter out excess liquid silicone (180b) (200b, 40) on the carrier substrate (150b).

[0031] Preferably, but optionally, the uncured liquid silicone leaving the silicone gel (180b) of the desired thickness may contain an antibacterial substance such as 3 wt% of a non-leaching polycoat antibacterial agent (3-trihydroxysilylpropyldimethyloctadecylammonium chloride) or 3 wt% of a silver oxide salt. The perforated mesh (210, 50) is drawn from the roll (215) and passed over the "lay down" roller (220) and brought into contact with the uncured silicone (200b, 40) on the carrier substrate (150b). The resulting material is then passed through a tunnel oven (230) to apply heat to effect crosslinking of the silicone and form a web (340) of the perforated mesh material (45) at least partially impregnated on the carrier substrate 150b, and the resulting web (340) is wound onto a new master roll (355).

[0032] Figure 6a is a schematic diagram showing a preferred manufacturing process of laminating together two webs (280) and (340) (i.e., the web (280) of the IPN / gel film (15) and the web (340) of the perforated mesh material (45) that is at least partially impregnated), placing them on a suitable release liner, and die-cutting the shape therefrom. Figure 6b is an enlarged view of a part (the dashed circle marked "A") of Figure 6a. A release liner (240) such as polypropylene-coated paper or polyester film passes through a slitting station (the dashed frame 250), and a slit liner (260) having a butterfly fold, perforations, or other suitable means ("slits") is formed to finally remove the finished coating material and make it easy to apply. The slit liner (260) passes under an idler roller (270). The web (280) of the IPN / gel film (15) disposed on the carrier substrate (150a) is unwound from the master roll (290) with the gel side facing the slit liner (260). The carrier substrate (150a) attached to the web (280) of the IPN / gel film (15) in the manufacturing process of Figure 5a for manufacturing the web (280) is then removed from the IPN / gel film (15), wound back onto the roll (300), and discarded or preferably recycled. The web (280) of the IPN / gel film (15) passes around the idler roller (270) and meets the slit liner (260). Optionally but preferably, before the web (280) of the IPN / gel film (15) passes around the idler roller (270), the web (280) of the IPN / gel film (15) may be passed through a suitable cutting tool to form a window (70) through the IPN / gel film (15). In this way, the optionally windowed web of the IPN / gel film (15) is brought into contact with the slit release liner (260) such that the gel side contacts the slit release liner (260) and the IPN (10) side faces away from the slit release liner to the opposite side. The IPN / gel film (15) (collectively shown by reference numeral (310) in Figures 6a and 6b) on the slit liner (260) then passes under a second idler roller (320).

[0033] A web (340) of a porous mesh material that is at least partially impregnated on a carrier substrate (150b) (i.e., a web (340) consisting of a web (45) of a porous mesh material (50) that is at least partially impregnated with silicone (110) and has a silicone-coated surface (40)) (which can both be identified by reference numeral (330) in FIGS. 6a and 6b) is drawn from a master roll (355) such that the mesh (50) side faces outward on the side opposite the roll (355) and the carrier substrate (150b) contacts an idler roller (350). The carrier substrate (150b) on the back surface is removed, wound back onto a roll (360), and discarded or preferably recycled. By the process of removing the carrier substrate (150b) from the silicone surface (40), holes (95) are formed where the silicone is not supported by the porous matrix (50, 80). The self-supporting web (335, 45) of the at least partially impregnated porous mesh material passes under the idler roller (350), around the idler roller (320), and meets the web (310) on the slit liner (260) (i.e., the IPN side (10) of the IPN / gel film (15)). Referring to FIG. 6b, it is a self-supporting web (335, 45) of a porous mesh web material that is at least partially coated (i.e., used to form a layer of a wound dressing (60) including an apertured mesh layer (50) that is at least partially impregnated with silicone (110) and has a silicone-coated surface (40)). And in FIGS. 1a and 1b, it is identified by reference numeral (45), and additionally in FIG. 6b, 335 passes around the roller 320, and the coated side of the coated porous mesh web material (i.e., the side having the silicone-coated surface (40)) contacts the IPN side (10) of the IPN / gel film (15) of the web (310) disposed on the slit liner (260), forming a structure (370).

[0034] Preferably, in order to firmly adhere the two layers together, a nip roller (not shown) that applies pressure at the laminate point is used. It should be noted that in the described process, holes (95) are formed when the carrier substrate (150b) is removed from the web (340) of the porous mesh material that is at least partially impregnated. This is because the self - standing silicone (200b) not supported by the matrix of the porous mesh 50 (e.g., monofilament 80) adheres essentially to the carrier substrate (150b), and as a result, openings (95) are formed in the at least partially impregnated porous mesh (45, 335).

[0035] Next, the constituent material (370) of the layered porous web (45) bonded to the IPN side (10) of the layer (15) on the slit release liner (260) is passed through a die - cutting device (380) and punch - cut into the shape of the final wound dressing. Thereafter, the remaining matrix that was not cut from the web (370) (i.e., the remaining material (390) left over from the cutting process) is either discarded or preferably wound back onto a roll (400) to be recycled. The individual dressings (60) (shown by reference number (410) in FIG. 6a) obtained through these steps are packaged and sterilized according to established methods.

[0036] Next, returning to FIG. 1b, a preferred alternative embodiment of the present invention is shown.

[0037] Here, the covering material (60') of the present invention is substantially the same as the wound dressing (60), and includes a semi-sealing polymer film layer such as an IPN thin film (10) coated with a silicone gel (20). The wound dressing (60') is formulated such that the thin film (10') is semi-adhesive by itself, and thus has a gentle adhesive wound contact surface (30'). Therefore, it includes a semi-adhesive polymer film layer such as an IPN thin film (10') not coated with a silicone gel (20). Thus, like the gentle adhesive wound contact surface (30) of the wound dressing (60), the adhesive thin film (10') allows the wound dressing (60') to be easily peeled off from the wound when desired, without the wound contact surface (30') integrating with the wound. Similar to the adhesive wound contact surface (30) of the wound dressing (60), the low-adhesive wound contact surface (30') of the wound dressing (60') allows the wound dressing to fit well at a predetermined position on the wound, but it does not substantially adhere permanently to the wound or integrate substantially with the wound. Preferably, the thin film (10') may be a silicone / PTFE IPN film formulated to be semi-adhesive (i.e., having a gentle adhesion surface). Preferably, however, optionally, the thin film (10') may be fenestrated.

[0038] The wound dressing (60') may be prepared in the same manner as the wound dressing (60), except that the application of the silicone gel layer (20) can be omitted. Furthermore, like the wound dressing (60), the wound dressing (60') can be used in the same manner as the wound dressing (60), by bringing the wound contact surface (30') of the wound dressing (60') into contact with the wound, rather than bringing the wound contact surface (30) of the wound dressing (60) into contact with the wound.

[0039] Similar to the covering material (60), the covering material (60') may be designed to provide an exudate permeability rate at a desired flow rate (e.g., low, medium, high).

[0040] In a preferred embodiment of the present invention, a window penetrating the wound contact polymer film layer is included. However, if a porous or microporous polymer film is used, it is conceivable that no window or perforation is required to achieve the same function as the basic function of the present invention.

[0041] These variations in design, configuration, and process will be apparent to those skilled in the art. Therefore, the following examples are not intended to be limiting. It is clear that the relative layers of the coating material of the present invention can be substantially varied. In Example 1, an IPN / gel film with a thickness of about 40 microns is shown, but a thickness ranging from 10 microns to 200 microns is sufficient. Also, in Example 1, a woven fabric mesh with a thickness of 380 microns and a perforated mesh of about 420 microns that is finally partially impregnated are shown. These layers can be in the range of 100 microns to 600 microns and can be combined or independent.

[0042] Similarly, it is considered that the same coating material design can be realized using other materials. In this specification, the use of a window in the polymer film layer is described as a preferred embodiment. However, whether or not there is a window, a microporous thin film, particularly a thin film that reabsorbs or dissolves, may be used.

[0043] In addition to the cut coating material shapes described here, it is also a useful option to provide a small roll made of the material of the present invention without a release liner for applying a "tape-like" or circumferential wrap style.

[0044] Example 1: A continuous web of an IPN of polydimethylsiloxane and polytetrafluoroethylene was produced according to a method established on a suitable carrier substrate, shown and described in connection with FIG. 5a, and coated with a silicone gel using the apparatus and process shown. An IPN / gel film with a measured thickness of about 40 microns was produced, and then passed through a tool to form a window substantially as shown in FIG. 2a.

[0045] According to established methods, a web of woven fabric mesh with a thickness of approximately 380 microns was produced, and using the apparatus and process shown and described in relation to Figure 5b, the silicone gel was partially impregnated on a suitable carrier substrate to obtain a finished structure with a thickness of approximately 420 microns.

[0046] Using the apparatus and process shown and described in relation to Figures 6a and 6b, a layered porous coating was formed on a release liner of polypropylene-coated paper folded in a butterfly shape, cut into 13x25 cm sheets, and packaged and sterilized for final use.

[0047] Example 2: Example 1 was repeated except that a non-woven fabric mesh with a thickness of approximately 325 microns was used instead of the woven fabric mesh, using a desktop analog of the process described in relation to Figures 5a, 5b, 6a, and 6b. The non-woven fabric mesh was spunlace polyester with holes in an isotropic square pattern of 6 holes per linear cm. The thickness of the finished structure was approximately 365 microns.

[0048] Example 3: Examples 1 and 2 were repeated except that a silicone gel containing 3 wt% of a non-leaching polycoat antibacterial agent (3-trihydroxysilylpropyldimethyloctadecylammonium chloride) was used. That is, the uncured liquid silicone (180a) in the reservoir shown in Figure 5a contains 3 wt% of the non-leaching polycoat antibacterial agent (3-trihydroxysilylpropyl-dimethyloctadecylammonium chloride).

[0049] Example 4 Examples 1, 2, and 3 were repeated except that a silicone gel containing 3 wt% of a silver oxide salt was used. That is, the uncured liquid silicone (180a) in the reservoir shown in Figure 5a contains 3 wt% of the silver oxide salt.

[0050] Example 5: Repeat Examples 1 to 4 except using a silicone gel containing 3 wt% silver oxide salt. That is, the uncured liquid silicone (180b) in the reservoir shown in Figure 5b contains 3 wt% silver oxide salt.

[0051] Example 6: Repeat Examples 1 to 5 except using a silicone gel containing 3 wt% non-eluting polycoat antibacterial agent (3-trihydroxysilylpropyl dimethyloctadecylammonium chloride). That is, the uncured liquid silicone (180b) in the reservoir shown in Figure 5b contains 3 wt% non-eluting polycoat antibacterial agent (3-trihydroxysilylpropyl-dimethyloctadecylammonium chloride).

[0052] Example 7: Repeat Examples 1 to 6 except that the PTFE / silicone IPN (10’) is formulated with a silicone gel such that the wound contact surface (30’) is essentially adhesive, and the step of coating the IPN with the silicone gel using the apparatus and process shown and described in connection with Figure 5a is omitted.

[0053] Example 8: Repeat Example 7 except using a microporous resorbable polymer film made of a copolymer of polylactic acid, polylactide, trimethylene carbonate, and ε-caprolactone instead of the PTFE / silicone IPN film (10), imparting semi-adhesiveness to the wound contact surface (30’) by microporous capillary action, and curing by passing through an oven (230) at a low temperature due to the temperature sensitivity of the copolymer.

[0054] Preferably, according to the present invention, a method of treating various types of wounds comprises providing a wound dressing of the present invention, the wound dressing comprising a plurality of layers, wherein the first wound contact layer is a fenestrated or perforated semi-sealing thin film membrane that is essentially a sticky semi-adhesive gel or other polymeric formulation, and the second, more distal layer is a discontinuous silicone gel that partially penetrates or otherwise adheres to a perforated mesh, the steps of providing, applying the first wound contact layer to the wound to attach the wound dressing to the wound, wherein wound exudate passes through the wound dressing while limiting the integration of the wound dressing into the wound and the slippage and wrinkling of the wound dressing on the wound. In this embodiment, the first wound contact layer of the wound dressing, as well as the discontinuous silicone gel that partially penetrates or otherwise adheres to the perforated mesh, may contain an antibacterial substance such as 3% by weight of a non-leaching polycoat antibacterial agent (e.g., 3-trihydroxysilylpropyl dimethyloctadecylammonium chloride) or 3% by weight of a silver oxide salt.

[0055] According to the present invention, a method of treating a wound comprises providing a wound dressing of the present invention, the wound dressing comprising a plurality of layers, wherein the first wound contact layer is a semi-adhesive gel or other polymeric film, and the second, more distal layer is a perforated mesh, thus (a) limiting the slippage and wrinkling of the wound dressing on the wound, (b) allowing wound exudate to pass through the wound dressing, and (c) providing a moist healing environment to the wound while limiting the integration of the wound dressing into the wound. In this embodiment, the first wound contact layer of the wound dressing and the silicone gel of the perforated mesh that is at least partially impregnated may contain an antibacterial substance such as 3% by weight of a non-leaching polycoat antibacterial agent (e.g., 3-trihydroxysilylpropyl dimethyloctadecylammonium chloride) or 3% by weight of a silver oxide salt.

[0056] The perforated mesh may be a woven or knitted fiber material, or a non-woven material, or an extruded scrim.

[0057] Preferably, the method for manufacturing the multilayer wound dressing according to the present invention comprises: (1) creating a thin film having a gentle adhesion surface that contacts the appropriate wound (i.e., creating a thin film having an appropriate wound-contact low-adhesion surface); and (2) forming a porous mesh that is at least partially impregnated with a polymer gel such that the pores of the at least partially impregnated porous mesh remain open to the passage of wound exudate, the porous mesh having an outer surface facing away from the wound attachment site; and (3) attaching the thin film and the at least partially impregnated porous mesh to form a multilayer wound dressing having a wound contact surface and a distal surface, the wound contact surface being the gentle adhesion surface of the thin film that contacts the wound (i.e., the wound-contact adhesive surface), and the distal surface being the outer surface of the porous mesh. In a preferred embodiment of the method for manufacturing a multilayer wound dressing, the method may include forming a window in the thin film to create an opening for the passage of exudate. The thin film may be, for example, a semi-sealed polymer film such as a silicone / PTFE IPN film that is essentially adhesive and thus formulated to have a gentle adhesion surface.

Claims

1. A wound dressing material, comprising: a perforated mesh layer having a first surface and a second surface, wherein the first surface of the perforated mesh layer has an outer surface, and the perforated mesh layer comprises a material having a plurality of openings extending from the first surface of the perforated mesh layer to the second surface of the perforated mesh layer, and the perforated mesh layer coats at least a part of the material, at least partially impregnated with silicone to form a silicone coating on at least a part of the outer surface of the first surface of the perforated mesh layer, while at least a part of the openings is open so that exudate can move through the perforated mesh layer, the perforated mesh layer; a semi-sealed polymer film layer having a first surface and a second surface and having windows or perforations; the silicone at least partially impregnates the perforated mesh layer and forms a silicone coating on at least a part of the outer surface of the first surface of the perforated mesh layer adhered to the perforated mesh layer; the silicone coating on the outer surface of the first surface of the perforated mesh layer is adhered to the second surface of the semi-sealed polymer film layer; the wound dressing material has a wound contact surface, and the wound contact surface includes the first surface of the semi-sealed polymer film layer; the first surface of the semi-sealed polymer film layer has semi-adhesiveness with adhesiveness such that the semi-sealed polymer film layer adheres to the skin or the wound surface but does not adhere so strongly that the wound is damaged when peeled off, so that the wound dressing material stays at the wound position but does not substantially adhere permanently to the wound and does not substantially integrate with the wound, a wound dressing material.

2. The wound dressing material according to claim 1, wherein the semi-sealed polymer film layer is a semi-sealed thin film.

3. The wound dressing material according to claim 1, wherein the semi-sealed polymer film layer having windows or perforations is a semi-sealed polymer film layer having windows or perforations of silicone / PTFE IPN.

4. The wound dressing material according to claim 3, wherein the microporous resorbable polymer film is used instead of the semi-sealed polymer film layer having windows or perforations of silicone / PTFE IPN.

5. The wound dressing material according to claim 4, wherein the microporous resorbable polymer film comprises a copolymer of polylactic acid, polylactide, trimethylene carbonate, and e-caprolactone.

6. The wound dressing according to any one of claims 1 to 5, wherein the perforated mesh layer is a fiber material of a woven fabric, a fiber material of a knitted fabric, a non-woven fabric material, or an extruded scrim.

7. The wound dressing according to claim 2, wherein the semi-sealing polymer film layer is a silicone / PTFE IPN film.

8. The wound dressing according to any one of claims 1 to 7, further comprising an antibacterial substance contained in the silicone that partially penetrates into the perforated mesh or the silicone adhered by other means.

9. A method for manufacturing the wound dressing according to claim 1, comprising: (1) forming a semi-sealing polymer thin film having a first side and a second side to form a semi-sealing polymer film layer; (2) forming a window in the semi-sealing polymer thin film to form an opening for the passage of exudate; (3) forming a perforated mesh layer at least partially impregnated with silicone, the perforated mesh layer having an outer surface opposite to the wound application site, the perforated mesh layer having a first surface and a second surface, the first surface of the perforated mesh layer having an outer surface, the perforated mesh layer comprising a material having a plurality of openings penetrating from the first surface of the perforated mesh layer to the second surface of the perforated mesh layer, the perforated mesh layer at least partially impregnating silicone to coat at least a part of the material of the perforated mesh layer, forming a silicone coating on at least a part of the outer surface on the first side of the perforated mesh layer, while leaving at least some of the openings open so that exudate can move through the perforated mesh layer; (4) adhering the second surface of the semi-sealing polymer thin film to the silicone coating on the outer surface of the first surface of the perforated mesh layer to form a multi-layer wound dressing having a wound contact surface, the wound contact surface being the first surface of the semi-sealing polymer thin film. A method comprising the above steps.

10. A method for manufacturing the wound dressing according to claim 4, comprising: (1) Forming a semi-sealing polymer film layer by forming a thin film of a semi-sealing polymer, wherein the thin film has a first surface and a second surface, and the thin film is a microporous reabsorbable polymer film; (2) Forming a porous mesh layer at least partially impregnated with silicone, wherein the porous mesh layer has an outer surface opposite to the wound application site, the porous mesh layer has a first side and a second side, the first side of the porous mesh layer has an outer surface, and the porous mesh layer comprises a material having a plurality of openings penetrating from the first side of the porous mesh layer to the second side of the porous mesh layer, the step of at least partially impregnating the porous mesh layer with silicone to coat at least a part of the material constituting the porous mesh layer, while forming a silicone coating on at least a part of the outer surface of the first side of the porous mesh layer, and leaving at least a part of the openings open so that exudate can move through the porous mesh layer; (3) Adhering the silicone coating on the outer surface of the second surface of the thin film of the semi-sealing polymer and the first surface of the porous mesh layer to form a multilayer wound dressing having a wound contact surface, wherein the wound contact surface is the first surface of the thin film of the semi-sealing polymer; A method comprising the above steps.

11. A porous mesh layer, wherein the porous mesh layer has a first surface and a second surface, the first surface of the porous mesh layer has an outer surface, the porous mesh layer comprises a material having a plurality of openings extending from the first surface of the porous mesh layer to the second surface of the porous mesh layer, the porous mesh layer coats at least a part of the material comprising the porous mesh layer at least partially impregnated with silicone to form a silicone coating on at least a part of the outer surface of the first surface of the porous mesh layer, while at least a part of the openings are open so that exudate can move through the porous mesh layer; A polymer film layer enabling wet healing and treatment of exudate, the polymer film layer having a first surface and a second surface; A wound dressing material comprising a silicone gel layer that coats the first surface of the polymer film layer, wherein the silicone at least partially impregnates the porous mesh layer to form a silicone coating on at least a part of the portion adhered to the porous mesh layer among the outer surfaces of the first surface of the porous mesh layer, the coating of silicone on the outer surface of the first surface of the porous mesh layer is adhered to the second surface of the polymer film layer, and the silicone gel layer that coats the first surface of the polymer film layer is adhered to the polymer film layer, the wound dressing material has a wound contact layer, and the silicone gel layer that coats the first surface of the polymer film layer is the wound contact layer, since the silicone gel layer that coats the first surface of the polymer film layer has semi - adhesiveness with adhesiveness such that the wound dressing material adheres to the skin or the wound surface but does not adhere so strongly that the wound is damaged when peeled off, the wound dressing material stays at the wound position but does not substantially adhere permanently to the wound and does not substantially integrate with the wound, a wound dressing material, wherein the polymer film layer and the silicone gel layer that coats the first surface of the polymer film layer are windowed.

12. Furthermore, an antibacterial agent is included in the silicone gel layer that coats the first surface of the polymer film layer and / or in the silicone that partially penetrates or adheres by other means to the porous mesh. The wound dressing material according to claim 11.

13. A method for manufacturing the wound dressing material according to claim 11, (1) A step of forming a polymer film layer by forming a thin polymer film that enables wet healing and treatment of exudate, the thin film having a first surface and a second surface, (2) A step of adhering a silicone gel layer to the first surface of the thin film, the silicone gel layer having a first surface and a second surface, and the second surface of the silicone gel layer being adhered to the first surface of the thin film, (3) A step of forming windows in the polymer film and the silicone gel layer to form openings for the passage of exudate. (4) forming a porous mesh layer at least partially impregnated with silicone by at least partially impregnating a porous mesh with silicone, wherein the porous mesh layer has an outer surface remote from the wound application site, the porous mesh layer has a first surface and a second surface, the first surface of the porous mesh layer has the outer surface, the porous mesh layer comprises a material having a plurality of openings extending from the first surface of the porous mesh layer to the second surface of the porous mesh layer, the porous mesh layer is at least partially impregnated with silicone to coat at least a portion of the material comprising the porous mesh layer and form a silicone coating on at least a portion of the outer surface of the first surface of the porous mesh layer, while at least a portion of the openings are open to allow exudate to move through the porous mesh layer; (5) adhering the second surface of the thin polymer film to the silicone coating on the outer surface of the first surface of the porous mesh layer to form a multilayer wound dressing having a wound contact surface, wherein the wound contact surface is the first surface of the silicone gel layer, and since the silicone gel layer adhered to the first surface of the thin film is semi-adhesive, the wound dressing stays in place at the wound site but does not substantially adhere permanently to the wound and does not substantially integrate with the wound; A method comprising.

14. The method according to claim 9 or 10, further comprising selecting the window pattern of the semi-sealing polymer film layer and the perforation pattern of the porous mesh layer to form the relative shape of the window with respect to the mesh opening and generating a selected flow capacity of the exudate when using the wound dressing.

15. The method according to claim 13, further comprising selecting the window pattern of the polymer film layer and the perforation pattern of the porous mesh layer to form the relative shape of the window with respect to the mesh opening and generating a selected flow capacity of the exudate when using the wound dressing.

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