A zoned drainage visualization composite dressing and its preparation method

Abstract

This invention discloses a zoned drainage and visualization composite dressing and its preparation method. The invention spatially separates visualization and fluid management through radial functional zoning. The central zone uses a transparent gel with a lateral drainage structure to achieve both visualization and active lateral drainage, while the outer peripheral zone uses a cleverly designed physical geometry to generate asymmetric capillary resistance, achieving a passive unidirectional drainage valve effect. This maintains long-term transparency in the central area while efficiently managing exudate, thus enabling the two zones to work synergistically. Furthermore, the preparation process of this invention is based on hot needle rolling and gel casting, making it suitable for continuous industrial production.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials, and in particular relates to a medical wound dressing, specifically a zoned drainage visual composite dressing and its preparation method. Background Technology

[0002] In clinical wound care, the management of exudate and continuous monitoring of the wound healing process are two core factors affecting the treatment efficacy. However, there is an irreconcilable technical contradiction between the transparency and absorbency of existing conventional medical dressings.

[0003] On the one hand, highly absorbent dressings such as transparent hydrogels will undergo significant volume expansion and phase change turbidity after absorbing wound exudate, leading to decreased transparency and making it difficult for medical staff to continuously observe the wound. On the other hand, if only a central hole is created in an opaque, highly absorbent pad for localized visibility, exudate generated in the central area cannot be effectively drained, easily causing fluid accumulation in the central area. Furthermore, after receiving exudate, traditional absorbent dressings typically exhibit disordered lateral diffusion within the core, easily spreading to the healthy skin surrounding the wound, causing skin maceration and even secondary expansion of the ulcer area.

[0004] Existing negative pressure assisted drainage dressings require an external negative pressure source to drive exudate flow. While offering high drainage efficiency, their reliance on continuous mechanical devices makes them unsuitable for outpatient dressing changes or patient-managed chronic wound scenarios. Furthermore, they can easily lead to excessive drying of wounds with small amounts of exudate, limiting their clinical application. In addition, existing unidirectional drainage dressings rely on surface tension and lack passive self-driving drainage properties, failing to achieve coordinated zonal absorption with central visibility and efficient peripheral absorption. In terms of manufacturing, the commonly used electrospinning or laser processing techniques result in high manufacturing costs. Summary of the Invention

[0005] At least in view of the technical defects in existing technologies where the transparency and visibility of dressings cannot be simultaneously achieved with their absorbency and drainage performance, this invention provides a zoned unidirectional drainage visual composite dressing and its preparation method for use in the management of exudate and monitoring of healing in mild or moderate exudative wounds.

[0006] This invention spatially separates visualization and fluid management through radial functional partitioning. The visible area achieves visualization with a transparent gel and a specific flow-guiding structure on its bottom surface, while actively guiding fluid in a direction substantially parallel to the skin surface. The absorbent area, with its uniquely designed physical geometry, generates asymmetric capillary resistance to achieve a passive, unidirectional flow-guiding valve effect. This maintains long-term transparency of the visible area while efficiently managing fluids, such as exudate, thus enabling the two areas to work synergistically. Furthermore, in some embodiments, this invention uses hot needle rolling and gel casting to prepare the composite dressing, suitable for continuous industrial production. Specifically, this invention includes the following:

[0007] A first aspect of the present invention provides a zoned drainage and visualization composite dressing, comprising an absorbent area and a visible area, wherein: The absorption area includes a first backing layer, a wound contact layer, and an absorption layer located between the first backing layer and the wound contact layer. The wound contact layer is provided with a first flow guiding structure, which is configured to guide the fluid generated by the skin corresponding to the absorption area unidirectionally to the absorption layer along a first direction. The visible area includes a second backing layer and a transparent gel layer, and the transparent gel layer has a second flow guiding structure on the side close to the skin, which is configured to guide the fluid generated by the skin corresponding to the visible area to the absorption layer of the absorption area in a second direction. Wherein, the first direction refers to a direction substantially from the skin surface to away from the skin surface, and the second direction refers to a direction substantially extending along the skin surface.

[0008] In some embodiments, according to the partitioned flow-guiding visual composite dressing of the present invention, the first flow-guiding structure includes a perforated structure extending along the first direction, and in any longitudinal section along the first direction, the perforated structure includes: The first inclined side has a first endpoint located at the upper part and a second endpoint located at the lower part; The second inclined side has a third endpoint located at the top and a fourth endpoint located at the bottom; Wherein, the first endpoint and the third endpoint are spatially spaced apart, thereby forming a top-side opening distance between the first endpoint and the third endpoint; The second endpoint and the fourth endpoint are spatially spaced apart, thereby forming a bottom opening distance between the second endpoint and the fourth endpoint; The bottom opening and the top opening are opposite each other in the longitudinal direction, and the distance between the top openings is less than the distance between the bottom openings; Preferably, the hole structure has a structure that runs from top to bottom and is basically frustum-shaped or funnel-shaped.

[0009] In some embodiments, according to the partitioned flow-guiding visual composite dressing of the present invention, the first flow-guiding structure includes a plurality of said perforation structures, thereby forming an array of flow-guiding perforations, and at least one of said perforation structures in the array of flow-guiding perforations includes an anti-backflow annular rolled edge structure formed on the outer periphery of the top opening of said perforation structure and protruding away from the skin along said top opening, such that the anti-backflow annular rolled edge structure is entirely located in the external space of said perforation structure.

[0010] In some embodiments, the partitioned drainage visualization composite dressing according to the present invention, wherein the distance from the second endpoint to the fourth endpoint is 100-300 μm, the interior angle formed at the extension connection of the first inclined side and the second inclined side is 30°-60°, and the distance from the first endpoint to the third endpoint is 20%-45% of the distance from the second endpoint to the fourth endpoint.

[0011] In some embodiments, the partitioned drainage visualization composite dressing according to the present invention, wherein the wound contact layer comprises a hydrophobic base membrane and a skin adhesion layer, and the first drainage structure is disposed on the hydrophobic base membrane.

[0012] In some embodiments, the partitioned flow-guiding visual composite dressing according to the present invention, wherein the second flow-guiding structure includes microgrooves; Preferably, the microgrooves include at least one of radial microgrooves, transverse microgrooves, intersecting microgrooves, circumferential microgrooves, and radial microgrooves; Preferably, the outlet end of the second flow guiding structure extends to the edge of the transparent gel layer and contacts the absorbent layer, thereby forming a continuous capillary flow channel.

[0013] In some embodiments, the zoned drainage visualization composite dressing according to the present invention, wherein the second backing layer is a transparent and breathable backing layer; or the first backing layer and the second backing layer are integrally formed.

[0014] In some embodiments, the zoned drainage visualization composite dressing according to the present invention, wherein the absorbent layer comprises a polysaccharide nonwoven felt or a cellulose nonwoven felt with a superabsorbent resin.

[0015] A second aspect of the present invention provides a method for preparing the partitioned drainage visual composite dressing according to any one of the above claims, wherein the method includes the following steps: A first backing layer, a wound contact layer, and an absorbent layer located between the first backing layer and the wound contact layer are provided, and a first flow guiding structure is provided in the wound contact layer to guide the fluid generated by the skin corresponding to the absorbent area unidirectionally to the absorbent layer along a first direction. A second backing layer and a transparent gel layer are provided, and a second flow-guiding structure is provided on the side of the transparent gel layer close to the skin, thereby guiding the fluid generated by the skin corresponding to the visible area to the absorption layer of the absorption area along the second direction; Wherein, the first direction refers to a direction substantially from the skin surface to away from the skin surface, and the second direction refers to a direction substantially extending along the skin surface.

[0016] In some embodiments, according to the preparation method of the present invention, the step of providing a first drainage structure in the wound contact layer includes preparing a plurality of porous structures on a hydrophobic base membrane, thereby forming a drainage hole array, and forming an anti-backflow annular rolled edge structure at the top opening of at least one porous structure of the drainage hole array; or The step of setting the second flow-guiding structure on the side of the transparent gel layer near the skin includes pouring hydrogel prepolymer onto a mold or fluorinated release film with a texture on the surface that matches the microgrooves, curing and demolding to obtain a transparent gel with the second flow-guiding structure on the lower surface, and cutting the gel to the size of the visible area.

[0017] The beneficial effects of this invention include: (1) Resolving the contradiction between central fluid accumulation and radiolucency: This invention embeds a transparent gel in the central visible area and constructs transverse drainage microgrooves at the bottom of the gel. Utilizing the capillary pump effect generated by the microgrooves, the exudate generated in the central wound is continuously and actively drained to the outer edge absorption area. This ensures high transparency in the central area (facilitating non-invasive real-time wound observation) while avoiding wound maceration caused by central fluid accumulation.

[0018] (2) One-way flow valve effect to prevent backflow: The three-dimensional micropores of the wound contact layer are prepared by thermal needle technology, combined with the heat-melted thickened edge structure of the small end, which provides strong anti-collapse support for the fluid. The large end absorbs exudate, and the small end, together with the super absorbent resin above, forms a one-way conduction of volumetric fluid, which can block the backflow of liquid after the absorbent layer is saturated, and maintain an ideal moist healing microenvironment for the wound.

[0019] (3) Effectively prevents maceration of healthy skin at the edge: The combination of microporous unidirectional drainage and open-pore absorption layer strictly limits exudate to the outer absorption area, effectively preventing maceration damage to healthy skin around the wound.

[0020] (4) Easy to industrialize and mass-produce: The structural design of the present invention does not rely on expensive laser processing or photo-initiated etching equipment. By utilizing a combination of technologies such as hot needle piercing roll pressing, die cutting and casting, it is conducive to continuous industrial production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the planar structure of the composite dressing of the present invention, showing the radial partitioning relationship between the central visible area and the edge guiding and absorbing area.

[0022] Figure 2 This is a schematic diagram of the longitudinal cross-sectional layer structure of the composite dressing of the present invention.

[0023] Figure 3 This is a schematic diagram of the transparent hydrogel and the microgroove arrangement on the bottom surface of the present invention.

[0024] Figure 4 This is a schematic diagram of the hydrophobic membrane with a micropore array of the present invention.

[0025] Figure 5 and Figure 6 This is a partially enlarged schematic diagram of the flow-guiding micropore structure of the present invention.

[0026] Explanation of reference numerals in the attached figures: 1-Visible area, 2-Absorbable area, 3-First backing layer, 4-Absorbable layer, 5-Wound contact layer, 6-First drainage structure, 601-Top side opening, 602-Bottom side opening, 603-Anti-backflow annular rolled edge structure, 604-Porous structure, 7-Second backing layer, 8-Transparent gel layer, 9-Second drainage structure, 10-Hydrophobic base membrane, 11-First inclined side, 12-Second inclined side, 13-First end point, 14-Second end point, 15-Third end point, 16-Fourth end point, 17-Root connection segment, 18-Transition bending segment, 19-Rolled back bending segment. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the invention, but rather as a more detailed description of certain aspects, features, and embodiments of the invention. Furthermore, the components in the drawings are not necessarily drawn to scale. For example, the dimensions of some components or regions in the drawings may be enlarged for the sake of understanding the embodiments of the invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that the upper and lower limits of the range and each intermediate value between them are specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention.

[0030] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of the embodiments of the present invention. In the description of the present invention, it should be noted that, unless otherwise stated, the terms "set," "connect," or similar terms should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0031] Spatial relation terms such as "below" and "above" are used for descriptive convenience to explain the positioning of one component relative to another component, indicating that these terms are intended to cover different orientations of components other than those shown in the figure. Additionally, phrases such as "one component above / below another component" can indicate that two components are in direct contact, or that there are other components between them. Furthermore, terms such as "first" and "second" are also used to describe individual components, areas, parts, etc., without specifically indicating order or sequence, and should not be considered restrictive. Similar terms are used throughout the description to represent similar elements.

[0032] Composite dressing In one aspect, the present invention provides a partitioned unidirectional flow visualization composite dressing, the composite dressing being radially divided into an absorption zone 2 and a visibility zone 1.

[0033] In this invention, the absorption zone 2 includes a first backing layer 3, a wound contact layer 5, and an absorption layer 4 located between the first backing layer 3 and the wound contact layer 5. The wound contact layer 5 is provided with a first flow guiding structure 6, which is configured to guide the fluid generated by the skin corresponding to the absorption zone 2 unidirectionally to the absorption layer 4 along a first direction.

[0034] The visible area 1 of the present invention includes a second backing layer 7 and a transparent gel layer 8, and the transparent gel layer 8 is provided with a second flow guiding structure 9 on the side close to the skin, which is configured to drive the fluid generated by the skin corresponding to the visible area 1 to the absorption layer 4 of the absorption area in a second direction through capillary effect and exudate accumulation pressure difference.

[0035] In this invention, the first direction refers to a direction substantially from the skin surface to away from the skin surface, and the second direction refers to a direction substantially extending along the skin surface.

[0036] In this invention, the first backing layer 3 and the second backing layer 7 are transparent and breathable backing layers, covering the top of the dressing. The first backing layer 3 is in contact with the upper surface of the open-cell absorbent layer, and the second backing layer 7 is in contact with the upper surface of the transparent gel sheet. The first backing layer 3 and the second backing layer 7 are independently disposed or integrally formed. In a preferred embodiment, the first backing layer 3 and the second backing layer 7 are integrally formed, thereby sealing and encapsulating the functional layers, preventing external contamination, and allowing water vapor to escape. In a more preferred embodiment, the transparent and breathable backing layer has a visible light transmittance (400-700 nm) of at least 85% in the area corresponding to the central visible region.

[0037] In this invention, the material of the backing layer is not particularly limited, but is preferably a medical-grade thermoplastic polyurethane film. The thickness of the backing layer can be adjusted as needed. In a preferred embodiment, the thickness of the backing layer is 25-35 μm, for example, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35 μm. In a preferred embodiment, the moisture permeability (MVTR) of the backing layer is not less than 3500 g / (m²). 2 •24h), for example, not less than 4000, 5000, 6000, 7000, or 8000 g / (m 2 •24h) to ensure the wound is in a suitable moist healing microenvironment.

[0038] In a preferred embodiment, the edge region of the first backing layer 3 is connected to the edge region of the wound contact layer 5, forming an approximately closed pocket-like space accommodating each functional layer. The connection method is not particularly limited and can be achieved by any suitable method known in the art, including but not limited to heat sealing welding or adhesive bonding. The connection can be surface, line, or point-like. Heat sealing welding can be performed using hot roller calendering or ultrasonic welding, and adhesive bonding can use medical acrylic pressure-sensitive adhesive or hot melt adhesive, applied evenly along the edge. This edge connection method eliminates the need for separate processes of fixing each functional layer to the backing layer and the contact layer, reducing manufacturing costs and preventing edge leakage.

[0039] In this invention, the absorbent layer 4 has a central opening for embedding a transparent gel layer. The material of the absorbent layer 4 is not particularly limited, as long as it has a suitable water absorption ratio. Preferably, the absorbent layer 4 is made of polysaccharide nonwoven felt or cellulose nonwoven felt containing superabsorbent polymer (SAP), with a SAP mass fraction preferably between 10% and 20%, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%. When the SAP mass fraction is below 10%, the absorption ratio is insufficient, and exudate easily accumulates in the central area. When it is above 20%, the SAP expands excessively after absorbing and swelling, causing excessive radial compression of the gel at the central opening of the absorbent layer, affecting the gel's embedding and sealing.

[0040] In this invention, the size of the central opening in the absorbent layer 4 corresponds to the external dimensions of the transparent gel sheet. The porous absorbent layer and the porous hydrophobic bottom membrane are integrally composited to form an overall framework with a central opening, thereby simplifying the assembly process and ensuring the alignment accuracy of each layer.

[0041] In this invention, the transparent gel is embedded in the central opening of the absorbent layer 4, with its upper surface facing the second backing layer 7 and its lower surface facing the wound. The lower surface of the transparent gel is provided with a second flow guiding structure 9.

[0042] In a preferred embodiment, the second diversion structure 9 is an array of at least one microgroove selected from radial microgrooves, transverse microgrooves, crisscrossing microgrooves, circumferential microgrooves, and radial microgrooves extending from the center outwards, for transporting exudate generated in the central visible area from the center to the edge absorption area. The formation of the microgrooves (sometimes referred to herein as diversion channels) is not particularly limited and can be achieved by known methods, such as, but not limited to, molding or imprinting. After the exudate enters the dressing from the wound side through the wound contact layer 5, it first collects in the central visible area, then diffuses outwards along the diversion channels on the bottom surface of the transparent gel, and is ultimately absorbed and locked by the absorbent layer, thereby achieving central visibility, edge diversion, and absorption.

[0043] In this invention, the linewidth and depth of the flow channel can be controlled within a suitable range. When the aspect ratio of the flow channel is less than 0.3, the capillary driving force is insufficient; when the aspect ratio is greater than 0.8, the channel wall is prone to collapse and deformation when the hydrogel material is demolded from the PDMS mold, affecting the geometric accuracy of the flow channel. In a preferred embodiment, the linewidth of the flow channel is 50-200 μm, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200 μm; the depth is 0.3-0.8 times the linewidth, for example, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 times. The outlet end of the flow channel extends to the outer peripheral edge of the transparent gel and directly contacts the upper surface of the absorbent layer, thereby forming a continuous capillary flow channel.

[0044] In this invention, the material of the transparent gel layer 8 is not particularly limited, but is preferably a medical cross-linked polyurethane hydrogel with a transmittance of not less than 88% at a wavelength of 550 nm, for example, not less than 89%, 90%, or even greater than 90%; a refractive index of 1.33-1.40, for example, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40; a thickness of 1.0-2.0 mm, for example, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0 mm; and a liquid absorption swelling rate of not more than 500%, for example, not more than 450%, 400%, 350%, 300%, 250%, 200%. The elastic modulus of the transparent gel can be controlled within a suitable range. When the elastic modulus is below 5 kPa, the mechanical strength of the gel sheet is insufficient, while when it is above 30 kPa, the gel is too hard and cannot adhere to irregular wound surfaces. In a preferred embodiment, the elastic modulus of the cured transparent gel is 5-30 kPa, for example, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30 kPa.

[0045] In this invention, the method of fixing the transparent gel is not particularly limited. Preferably, in its free state, at least a portion of the outer diameter of the transparent gel is larger than the inner diameter of the opening, and when assembled into the opening, radial elastic pressure is applied to the wall of the opening based on the size difference between the transparent gel and the opening. More preferably, the diameter of the transparent gel sheet is 0.5-1.5 mm larger than the diameter of the opening at the center of the absorbent layer (e.g., 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 mm), thereby relying on the elasticity of the gel itself to generate radial pressure and fit tightly with the opening wall, without the need for additional adhesive dressings for fixation. The interference fit between the transparent gel and the opening can be controlled within a suitable range. When the interference fit is less than 0.5 mm, the fitting pressure is insufficient, and the gel sheet may loosen during flipping or use. When the interference fit is greater than 1.5 mm, the insertion operation is difficult, and excessive radial pressure will cause excessive compression of the absorbent layer fibers at the opening wall, affecting the unobstructed flow of the liquid absorption channel. Preferably, the backing layer provides further axial constraint during encapsulation to prevent the gel sheet from falling off in the vertical direction, thus forming a double fixation.

[0046] In this invention, the wound contact layer 5 includes a hydrophobic base membrane 10 (sometimes referred to herein as a porous hydrophobic base membrane) and a skin adhesion layer coated thereon on the skin-facing side. The base membrane has a first flow-guiding structure 6 disposed in the region corresponding to the absorption area. The first flow-guiding structure 6 includes a porous structure extending along the first direction. In some embodiments, multiple porous structures collectively form a flow-guiding array, which is configured to allow wound exudate to spontaneously flow unidirectionally from the wound area to the edge flow-guiding absorption area.

[0047] In this invention, the material of the porous hydrophobic bottom membrane is not particularly limited, but is preferably a hydrophobic thermoplastic polyurethane film. The membrane thickness can be controlled within a suitable range to ensure formability and one-way valve effect. Preferably, the thickness of the bottom membrane is 30-80 μm, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 μm, such as 30-70, 30-60, 30-50, 40-80, 40-70, 40-60 μm. When the membrane thickness is too low, the membrane surface is easily torn during the hot needle puncture process, and the rolled edge cannot be stably formed; when the membrane thickness is too high, it will cause the depth of the flow-guiding array (e.g., conical channel) to be limited, the difference between the large and small diameters will be reduced, the one-way valve effect will be weakened, and the overall thickness of the dressing will increase, affecting the fit and flexibility.

[0048] In this invention, the first flow guiding structure 6 includes at least one pore structure 604. The overall structure of the pore structure 604 is located from the upper end face to the lower end face of the hydrophobic base membrane 10. The anti-backflow annular rolled edge structure 603 is continuously formed circumferentially at the upper end of the pore structure 604 and extends outward to form a roughly funnel-shaped structure.

[0049] In this invention, on any longitudinal section along the central axis of the first direction, the hole structure 604 includes: The first inclined side 11 has a first end point 13 located at the upper part and a second end point 14 located at the lower part; The second inclined side 12 has a third end point 15 located at the upper part and a fourth end point 16 located at the lower part; Wherein, the first endpoint 13 and the third endpoint 15 are spatially spaced apart, thereby forming a top-side opening distance between the first endpoint 13 and the third endpoint 15; The second endpoint 14 and the fourth endpoint 16 are spatially spaced apart, thereby forming a bottom opening distance between the second endpoint 14 and the fourth endpoint 16; The bottom opening 602 and the top opening 601 are opposite each other in the longitudinal direction, and the distance between the top opening 601 and the bottom opening 602 is smaller than the distance between the top opening 601 and the bottom opening 602. The first inclined side 11, the second inclined side 12, the top opening 601 and the bottom opening 602 together form a wound exudate flow space that runs from top to bottom and is roughly frustum-shaped or funnel-shaped.

[0050] In a preferred embodiment, an anti-backflow annular rolled edge structure 603 is formed on the outer periphery of the top opening 601 of the pore structure 604, and protrudes away from the skin along the top opening 601, such that the anti-backflow annular rolled edge structure 603 is entirely located in the external space of the pore structure 604. In some embodiments, the anti-backflow annular rolled edge structure 603 is continuously formed circumferentially at the top opening 601 of the pore structure 604, and extends away from the top opening 601 towards the side away from the wound exudate flow space, such that the anti-backflow annular rolled edge structure 603 is entirely located in the external space of the pore structure 604.

[0051] In this invention, on any longitudinal section passing through the central axis of the first flow guiding structure 6, the anti-backflow annular rolled edge structure 603 includes: The root connecting segment 17 extends outward in a generally radially outward direction and axially away from the bottom opening 602, starting from the upper edge boundary corresponding to the first endpoint 13 of the first inclined side 11 and the third endpoint 15 of the second inclined side 12. The root connecting segment 17 has a first arc surface facing the absorbent layer 4 and a second arc surface facing the wound contact layer 5. The transitional curved section 18 extends from the end of the root connecting section 17 with a first radius of curvature in a direction away from the top side opening 601, while gradually extending towards the upper surface of the wound contact layer 5. The winding bend section 19 extends continuously from the end of the transition bend section 18 and bends toward the hole structure 604 with a second radius of curvature smaller than the first radius of curvature, so that the extension path of this section gradually approaches the hole structure 604. The root connecting section 17, the transition bending section 18, and the winding back bending section 19 are smoothly connected in sequence and together form a rolled edge structure in an inward-curling shape in space. The overall extension trajectory of the rolled edge structure is shown on the vertical projection of the plane where the rolled edge structure is located as starting from the upper edge boundary, arching outward and upward, and then rolling downward and towards the hole structure 604. Preferably, the anti-backflow annular rolled edge structure 603 is configured such that when wound exudate comes into contact with its first arc surface through the top side opening 601, it can flow out along the first arc surface and eventually be released downward or diffused outward from the rolled back bend section 19 without entering the internal space of the hole structure 604.

[0052] In this invention, the rolled edge is formed by the following process: In the hot needle piercing and rolling process at the small opening (top side opening 601) between the first endpoint 13 and the third endpoint 15, the needle tip temperature is higher than the initial softening temperature of the film hard segment, thereby pushing the molten material on the piercing side outward and solidifying it in situ while piercing the base film, forming a smooth, thickened rolled edge around the small opening (top side opening 601). This invention has found that this structure can guide the exudate out of the pore structure while ensuring that the wound exudate does not backflow.

[0053] In this invention, the diameter D1 of the large end corresponding to the second endpoint 14 to the fourth endpoint 16 is 100-300 μm, for example, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300 μm; the inner angle formed by the extension connection of the first inclined side 11 and the second inclined side 12, i.e., the cone angle α, is 30°-60°, for example, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60°; the diameter D2 of the small end corresponding to the first endpoint 13 and the third endpoint 15 is 20%-45% of the diameter of the large end, for example, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 45%.

[0054] In this invention, the anti-backflow annular rolled edge structure 603 formed by the root connecting section 17, the transition bending section 18, and / or the winding back bending section 19 has a predetermined thickness. Preferably, the thickness of the anti-backflow annular rolled edge structure 603 formed by the heating and melting of the top opening 601 of the first flow guiding structure 6 is 1.2-2 times the thickness of the base film, preferably 1.2-1.8 times, for example 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, or 1.8 times. This thickness is defined as the maximum local thickness of the molten flange of the small end of the hole structure (i.e., the continuous region formed by the first endpoint and the third endpoint) in the cross-sectional direction of the hole structure. During measurement, at least three hole structures are randomly selected, and at least three positions are measured along the circumference of each hole structure, and the average value is taken as the rolled edge thickness.

[0055] In this invention, the distribution density of the flow guiding array is not particularly limited, but preferably, its distribution density is 100-350 units / cm². 2 Preferably 100-300 pieces / cm 2 For example, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300 pieces / cm 2 The unidirectional flow mechanism of the flow-guiding array is based on the Laplace equation, where the additional capillary pressure generated by the liquid in the capillary at the pore size d is ΔP = 4γcosθ / d. The larger pore size D1 at the larger end (bottom opening) corresponds to a smaller additional pressure; the smaller pore size D2 at the smaller end (top opening) is formed by the heat-fused crimp, creating a smooth arc surface at the edge of the smaller end (top opening). After the liquid passes through and forms a liquid film, the crimped structure stabilizes the meniscus, making the additional capillary pressure at the smaller end (top opening) significantly greater than that at the larger end (bottom opening). This creates a pressure barrier at the smaller end (top opening) that prevents the liquid from flowing backward. This mechanism is mainly influenced by the micropore geometry and is independent of the liquid's chemical composition.

[0056] In this invention, the material of the skin adhesion layer is not particularly limited, as long as it can achieve stable skin adhesion. Examples include, but are not limited to, any one or a combination of medical soft silicone gel adhesive layers or acrylic pressure-sensitive adhesive layers. In a preferred embodiment, the skin adhesion layer is applied using a patterned coating process, with a coating amount of 80-150 g / m². 2 For example, 80, 90, 100, 110, 120, 130, 140, 150 g / m 2 The presence of the skin adhesion layer allows the dressing to be directly adhered to the skin around the wound without the need for additional securing tape.

[0057] In this invention, the total thickness of the composite dressing in its natural state is 1-3 mm, for example 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, or 3 mm.

[0058] Preparation method In one aspect, the present invention provides a method for preparing the dressing described in any of the above embodiments, comprising the following steps: A first backing layer, a wound contact layer, and an absorbent layer located between the first backing layer and the wound contact layer are provided, and a first flow guiding structure is provided in the wound contact layer to guide the fluid generated by the skin corresponding to the absorbent area unidirectionally to the absorbent layer along a first direction. A second backing layer and a transparent gel layer are provided, and a second flow-guiding structure is provided on the side of the transparent gel layer close to the skin, thereby guiding the fluid generated by the skin corresponding to the visible area to the absorption layer of the absorption area along the second direction; Wherein, the first direction refers to a direction substantially from the skin surface to away from the skin surface, and the second direction refers to a direction substantially extending along the skin surface.

[0059] In some embodiments, the preparation method of the present invention includes: An opening is formed through the center of the absorbent layer, thereby forming a central visible area in the radial direction of the dressing and an edge guiding absorbent area surrounding the central visible area; A first flow-guiding structure (flow-guiding array) is formed in the wound contact layer in the region corresponding to the edge flow-guiding absorption zone. The flow-guiding array is configured to allow wound exudate to flow spontaneously unidirectionally from the wound area to the edge flow-guiding absorption zone. A transparent gel is filled into the opening, and a second flow-guiding structure (lateral flow-guiding structure) is formed on the surface of the transparent gel facing the wound contact layer to guide the wound exudate in the central visible area to the edge flow-guiding absorption area.

[0060] In a preferred embodiment, the method includes the following steps: Perforation preparation: A three-dimensional microporous flow-guiding array is prepared on a hydrophobic polyurethane base film using a hot needle piercing and rolling process, and an anti-backflow annular rolled edge structure is formed at the top side opening of the flow-guiding array. Adhesion and punching: The superabsorbent polymer is adhered to the porous hydrophobic polyurethane base film, and through holes are die-cut and punched in the central area of ​​the medium to form an integrated frame of porous hydrophobic bottom film and open-pore absorbent layer. The skin adhesion layer is coated on the skin-facing side of the base film using a patterned coating process to form a wound contact layer. Gel casting: Medical polyurethane hydrogel prepolymer liquid is cast into a mold or fluorine-containing release film with microgroove texture on the surface. After curing and demolding, a transparent gel with transverse guide grooves on the lower surface is obtained. The gel is then cut into transparent gels with dimensions larger than the opening size in each direction. Composite assembly: The transparent gel is embedded into the central opening with the flow channel side facing the wound contact layer side and the smooth side facing the backing layer side. The gel's own elasticity forms an interference fit with the hole wall. A breathable backing layer is then pressed on top and axial roller pressure is applied to bond and seal the layers. The edges are then heat-sealed and sterilized by irradiation to obtain the finished composite dressing.

[0061] In a more preferred embodiment, the method includes the following steps: Step 1, Perforation preparation: A flow-guiding array is prepared on a hydrophobic polyurethane (TPU) film using a hot needle piercing and rolling process, wherein the temperature of the hot needle roller is controlled to form an anti-backflow annular rolled edge structure. Step 2, bonding and punching: The superabsorbent polymer is bonded to the porous hydrophobic polyurethane film, and through holes are die-cut and punched in the central area to form an integrated framework of porous hydrophobic bottom film and open-pore absorbent layer; the skin adhesion layer is coated on the skin side of the wound contact layer using a patterned coating process. Step 3, Gel Casting: Pour medical polyurethane hydrogel prepolymer onto a polydimethylsiloxane (PDMS) mold or fluorinated release film with microgroove texture on the surface. After curing and demolding, a transparent gel with transverse channel grooves on the lower surface is obtained. Cut the gel into pieces that are the same shape as the central opening and whose dimensions in all directions are larger than the opening for later use. Step 4, Composite Assembly: The transparent gel obtained in Step 3 is embedded into the central opening obtained in Step 2 with the flow channel side facing the wound contact layer side and the smooth side facing the backing layer side, and the gel itself elasticity forms an interference fit with the hole wall; a breathable backing layer is pressed on top and axial roller pressure is applied to make each layer bonded and sealed, and the edges are heat-sealed; the finished composite dressing is obtained after irradiation sterilization.

[0062] In one specific implementation, the method includes the following steps: Step 1, Perforation Preparation: A conical three-dimensional micropore array is prepared on a hydrophobic polyurethane (TPU) film with a thickness of 30-80 μm using a hot needle piercing and rolling process; the temperature of the hot needle roller is controlled between 100-185℃. Step 2, bonding and punching: The superabsorbent polymer is bonded to the porous hydrophobic polyurethane film, and through holes are die-cut and punched in the central area to form an integrated framework of porous hydrophobic bottom film and open-pore absorbent layer; the skin adhesion layer is coated on the skin side of the wound contact layer using a patterned coating process. Step 3, Gel Casting: Pour medical polyurethane hydrogel prepolymer onto a polydimethylsiloxane (PDMS) mold or fluorinated release film with microgrooves of 50-200 μm linewidth and a depth of 0.3-0.8 times the linewidth. Cure at 55-65℃ for 2-3 h. After demolding, a transparent gel sheet with transverse drainage grooves on the lower surface is obtained. Cut the gel sheet into pieces that match the shape of the central opening and whose dimensions in all directions are 0.5-1.5 mm larger than the opening for later use. Step 4, Composite Assembly: The transparent gel sheet obtained in Step 3 is embedded into the central opening obtained in Step 2 with the flow channel side facing the wound contact layer side and the smooth side facing the backing layer side. The gel sheet's own elasticity forms an interference fit with the hole wall. A breathable backing layer is then pressed on top and axial roller pressure is applied at a pressure of 0.2-0.4 MPa to bond and seal the layers. The edges are then heat-sealed. The finished composite dressing is obtained after irradiation sterilization.

[0063] Example 1 A 30 μm thick medical-grade polyurethane (PU) film was selected as the breathable backing layer, with a moisture permeability of 5100 g / (m²). 2 •24h), with a transmittance of 92% at a wavelength of 550 nm.

[0064] A 1.0 mm thick carboxymethyl cellulose nonwoven felt was selected as the skeleton of the frame-shaped absorbent layer, and a superabsorbent resin was mixed in at a mass fraction of 12%. The material was then cut into square-round frame-shaped pieces with an outer edge size of 100 mm × 80 mm, a corner radius of 10 mm, a central opening of 50 mm × 36 mm, and a corner radius of 8 mm.

[0065] A 50 μm thick hydrophobic PU film was selected as the base layer of the wound contact layer. A conical micropore array was prepared using a hot needle roller puncture process. The hot needle roller temperature was 170℃, and the needle diameter was 120 μm. The resulting micropores had a large opening diameter of 180 μm, a small opening diameter of 50 μm, a cone angle of approximately 40°, and a distribution density of 300 pores / cm². 2 The thickness of the rolled edge at the small end is approximately 70 μm.

[0066] Preparation of transparent gel inserts: Medical-grade cross-linked polyurethane hydrogel prepolymer was poured into a PDMS mold with a cross-grid texture (line width 120 μm, depth 70 μm) on the surface and cured at 60℃ for 2 h. After demolding, the elastic modulus was measured to be 12 kPa, the liquid absorption swelling rate was 380%, the transmittance at 550 nm was 94%, the refractive index was 1.35, and the thickness was 1.2 mm. The inserts were then cut into 51 mm × 37 mm (rounded corner radius 8 mm) square-round pieces for later use.

[0067] Assembly: The transparent gel sheet is embedded into the central opening of the frame-shaped sheet, with its lower surface (channel surface) facing the wound contact layer and its upper surface (smooth surface) facing the backing layer. The gel sheet's elasticity and the interference fit between it and the opening wall create an interfacial contact pressure of approximately 0.5 kPa. A medical silicone gel adhesion layer is then applied to the wound contact layer facing the skin using a patterned coating process, with a coating amount of 100 g / m². 2 A transparent, breathable backing layer is applied and axial double-roll calendering is applied (roller pressure 0.3 MPa), followed by edge heat sealing. The product of Example 1 is obtained after irradiation sterilization.

[0068] Example 2 A 30 μm thick transparent medical polyurethane film was selected as the breathable backing layer, with a moisture permeability of 5200 g / (m²). 2 •24h), with a transmittance of 91% at 550 nm.

[0069] A 1.2 mm thick carboxymethyl cellulose nonwoven felt was selected as the skeleton of the frame-shaped absorbent layer. A superabsorbent resin was mixed in at a mass fraction of 12%, and the material was cut into square and round frame-shaped pieces with an outer edge size of 100 mm × 80 mm, a corner radius of 10 mm, a center opening of 50 mm × 36 mm, and a corner radius of 8 mm.

[0070] A 55 μm thick hydrophobic TPU film was selected as the bottom layer of the wound contact layer. A conical micropore array was prepared using a hot needle roller puncture process, with the hot needle roller temperature set at 175℃ and the needle diameter at 150 μm. The resulting micropores had a large opening diameter of 220 μm, a small opening diameter of 60 μm, a cone angle of approximately 42°, and a distribution density of 250 pores / cm². 2 The thickness of the rolled edge at the small end is approximately 77 μm.

[0071] Preparation of transparent gel sheets: Medical-grade cross-linked polyurethane hydrogel prepolymer was poured into a PDMS mold with a cross-grid texture (150 μm line width, 90 μm depth) on the surface and cured at 60℃ for 2.5 h. After demolding, the elastic modulus was measured to be 15 kPa, the liquid absorption swelling rate was 420%, the transmittance at 550 nm was 93%, the refractive index was 1.36, and the thickness was 1.5 mm. The gel sheets were then cut into 51 mm × 37 mm (8 mm corner radius) square-round sheets for later use.

[0072] Assembly: The transparent gel sheet is embedded into the central opening of the frame-shaped sheet, with its lower surface (channel surface) facing the wound contact layer and its upper surface (smooth surface) facing the backing layer. The gel sheet's elasticity and the interference fit between it and the opening wall create an interfacial contact pressure of approximately 0.5 kPa. A medical-grade silicone gel adhesion layer is then applied to the wound contact layer facing the skin using a patterned coating process, with a coating amount of 120 g / m². 2A transparent, breathable backing layer is applied and axial double-roll calendering is applied (roller pressure 0.3 MPa), followed by edge heat sealing. The product from Example 2 is obtained after irradiation sterilization.

[0073] Example 3 A 30 μm thick transparent medical polyurethane film was selected as the breathable backing layer, with a moisture permeability of 5050 g / (m²). 2 •24h), with a transmittance of 90% at 550 nm.

[0074] A 1.5 mm thick carboxymethyl cellulose nonwoven felt was selected as the skeleton of the frame-shaped absorbent layer. A superabsorbent resin was mixed in at a mass fraction of 10%, and the material was cut into square and round frame-shaped pieces with an outer edge size of 100 mm × 80 mm, a corner radius of 10 mm, a center opening of 50 mm × 36 mm, and a corner radius of 8 mm.

[0075] A 45 μm thick hydrophobic TPU film was selected as the bottom layer of the wound contact layer. A conical micropore array was prepared using a hot needle roller puncture process, with the hot needle roller temperature set at 162℃ and the needle diameter at 100 μm. The resulting micropores had a large opening diameter of 250 μm, a small opening diameter of 70 μm, a cone angle of approximately 33°, and a distribution density of 200 pores / cm². 2 The thickness of the rolled edge at the small end is approximately 60 μm.

[0076] Preparation of transparent gel sheets: Medical-grade cross-linked polyurethane hydrogel prepolymer was poured into a PDMS mold with a cross-grid texture (100 μm line width, 60 μm depth) on the surface and cured at 60℃ for 2 h. After demolding, the elastic modulus was measured to be 18 kPa, the liquid absorption swelling rate was 440%, the transmittance at 550 nm was 91%, the refractive index was 1.34, and the thickness was 1.8 mm. The gel sheets were then cut into 51 mm × 37 mm (8 mm corner radius) square-round sheets for later use.

[0077] Assembly: The transparent gel sheet is embedded into the central opening of the frame-shaped sheet, with its lower surface (channel surface) facing the wound contact layer and its upper surface (smooth surface) facing the backing layer. The gel sheet's elasticity and the interference fit between it and the opening wall create an interfacial contact pressure of approximately 0.5 kPa. A medical silicone gel adhesion layer is then applied to the wound contact layer facing the skin using a patterned coating process, with a coating amount of 80 g / m². 2 A transparent, breathable backing layer is applied and axial double-roll calendering is applied (roller pressure 0.3 MPa), followed by edge heat sealing. The product of Example 3 is obtained after irradiation sterilization.

[0078] Comparative Example 1 The difference between this comparative example and Example 1 is that a transparent PU hydrogel sheet is not embedded in the central opening; instead, a carboxymethyl cellulose nonwoven sheet of the same size is used for sealing. The remaining materials, structure, and preparation steps are the same as in Example 1, resulting in Comparative Example 1 dressing. This comparative example is used to investigate the effects of the central transparent viewing area and its lateral drainage structure on transparency and liquid drainage from the central area.

[0079] Comparative Example 2 The difference between this comparative example and Example 1 is that a smooth PDMS mold was used during the casting and curing of the gel sheet, and no drainage groove structure was formed on the lower surface, which was a completely smooth plane. The gel sheet was still embedded in the central opening in the same interference fit manner, and the remaining materials, structures and preparation steps were the same as in Example 1, resulting in the dressing of Comparative Example 2. This comparative example was used to investigate the effect of the drainage groove structure on the active drainage effect of exudate in the central area.

[0080] Comparative Example 3 The difference between this comparative example and Example 1 is that: immediately after the hot needle roller puncture is completed, the small end side is rolled with a cold roller (at room temperature) to flatten and reset the initially formed molten edge, so that the small end does not form a thickened curl and the edge of the small end is in a flat cut state. The remaining materials, structure and preparation steps are the same as in Example 1, resulting in the dressing of Comparative Example 3. This comparative example is used to investigate the effect of molten curl on unidirectional flow properties.

[0081] Comparative Example 4 The difference between this comparative example and Example 1 is that no superabsorbent resin is added to the frame-shaped absorbent layer; only the carboxymethyl cellulose nonwoven felt skeleton is retained. The remaining materials, structure, and preparation steps are the same as in Example 1, resulting in Comparative Example 4 dressing. This comparative example is used to investigate the effect of the frame-shaped superabsorbent layer on liquid absorption, liquid locking capacity, and lateral seepage prevention effect.

[0082] Test case The performance testing method is as follows: The dressings prepared in Examples 1-3 and Comparative Examples 1-4 were cut into samples of the same size and subjected to the following performance tests: 1) Transmittance Test: The transmittance of the central visible area at a wavelength of 550 nm was measured using a visible spectrophotometer. The transmitted light intensity without a sample was taken as 100% baseline. In Comparative Example 1, the central region is an opaque absorption layer, and the transmittance was recorded according to the measured value.

[0083] 2) Moisture permeability test: The finished product sample was placed in a test cup containing a certain amount of deionized water, sealed, and placed in an environment of (38±1)℃ and (10±2)% relative humidity. After 24 h, the moisture permeability was calculated by the weight loss method to evaluate the dressing's ability to transmit water vapor.

[0084] 3) Absorption capacity test: 0.9% sodium chloride solution (37℃) was used to simulate wound exudate. The dry weight of the sample was recorded as m0. The sample was completely immersed in the simulated exudate and left to stand for 30 minutes. After that, it was removed, the surface free liquid was drained, and the wet weight was recorded as m1. The absorption ratio (g / g) was calculated according to the formula (m1-m0) / m0 to reflect the maximum absorption capacity of the dressing.

[0085] 4) Lateral diffusion test: Add 0.5 mL of 0.9% sodium chloride solution containing 0.1% methylene blue to the center of the visible area of ​​the sample to simulate the exudate load of the central wound. After horizontal incubation for 10 min, use calipers to measure the maximum radius (mm) of the stained liquid spreading outward from the center in two mutually perpendicular directions to reflect the lateral diffusion control ability of the exudate within the dressing. Simultaneously record the residual liquid accumulation in the central visible area (rating criteria: none, very little, small amount, considerable, significant) and the leakage on the back side (rating criteria: none, occasional, slight, significant).

[0086] 5) One-way flow pressure threshold test: Place the sample horizontally with the contact layer side of the wound facing upwards. Continuously pass a 0.9% sodium chloride solution at 37°C through a thin tube onto the absorbent layer side surface, applying a gradient of increasing liquid column pressure (measured in mmH2O, increasing by 2 mmH2O per stage, with each stage held at pressure for 60 s). Observe in real time whether fluid seeps out from the contact layer side of the wound. Record the minimum liquid column pressure value at which fluid begins to seep out from the absorbent layer side to the contact layer side of the wound as the anti-backflow pressure threshold. This indicator is used to quantify the one-way valve effectiveness of the fused edge structure. In Comparative Example 1, because the central area is sealed by the absorbent layer, this area does not have a microporous structure; this test is performed in the corresponding area of ​​the peripheral edge flow-guiding absorption zone.

[0087] Table 1 Performance comparison of each embodiment and comparative example As can be seen from Table 1: Compared with the comparative example, the embodiment showed superior overall performance in terms of light transmittance, liquid absorption ratio, and lateral diffusion distance; Comparative Example 1 used an absorbent layer to directly seal the central area. Compared with Example 1, the light transmittance decreased significantly, indicating that without a transparent gel sheet, medical staff could not observe the wound healing status through the dressing. The amount of residual fluid in the center increased from a small amount to a significant amount, and the lateral diffusion distance increased, indicating that without a lateral drainage structure, the exudate in the central area could not be actively drained, continuously accumulating in the center and spreading outwards disorderly, significantly increasing the risk of wound maceration.

[0088] Comparative Example 2 was fitted with a transparent gel sheet of the same specifications as in Example 1, but the lower surface of the gel sheet was a smooth plane without a drainage channel structure. Compared with Example 1, this shows that without a drainage channel, there is no effective drainage mechanism for the exudate in the central wound, which accumulates below the gel sheet and diffuses outward disorderly along the path of least pressure difference. The difference in the central residual fluid between Comparative Example 2 and Comparative Example 1 indicates that the gel sheet's absorbency can partially alleviate the central fluid accumulation, but it cannot achieve active drainage. The drainage channel is a crucial structural element for the directional transport of central exudate.

[0089] Comparative Example 3 retained the complete geometry of the conical micropores but eliminated the melt-rolled edge treatment at the small opening. Compared to Example 1, the key difference lies in the unidirectional flow pressure threshold, with a difference exceeding 10 mmH2O. This result indicates that the conical geometry can only provide limited asymmetric capillary resistance, while the melt-rolled edge, by forming a smooth, thickened edge at the small opening and stabilizing the meniscus under the liquid film, significantly enhances the anti-reverse osmosis capability and is a key structural element for achieving the one-way valve effect. The decrease in back-side leakage from none to occasional occurrences further confirms that the barrier capability of the system in the reverse osmosis direction is significantly weakened after the melt-rolled edge is removed.

[0090] Comparative Example 4 only removed the superabsorbent resin from the frame-shaped absorbent layer. Compared to Example 1, the liquid absorption ratio plummeted from 25.6 g / g to 9.2 g / g, a decrease of 64%, indicating that the liquid absorption capacity of the pure cellulose nonwoven felt skeleton is very limited, and superabsorbent resin is the core material for achieving a large liquid absorption capacity. Due to insufficient liquid absorption, the absorbent layer reached saturation under a low permeation load, and the liquid remained in the absorbent layer and spread disorderly to the sides, resulting in an increase in the lateral diffusion distance from 12 mm to 22 mm. The amount of residual liquid in the center also increased significantly, and the anti-impregnation effect of the dressing was greatly deteriorated.

[0091] In summary, the combination of transparent gel sheet and transverse drainage channels is a necessary condition for achieving visualization of the central area and preventing liquid accumulation; neither can be omitted. The transverse drainage channels are the driving mechanism for actively and directionally transporting central exudate from the center to the periphery; the liquid absorption function of the gel sheet itself cannot replace the directional drainage function of the drainage channels. Although the melted edge does not affect the basic drainage channels of the micropores, it increases the anti-backflow pressure threshold and is a key structural element for achieving a reliable one-way valve effect and preventing backflow of exudate after the absorbent layer is saturated. Highly absorbent resin has an excellent effect on the liquid absorption ratio of the dressing; its absence will lead to a deterioration of the overall anti-impregnation performance.

[0092] This invention achieves excellent visualization performance and efficient exudate directional flow and absorption through the synergistic effect of transparent gel sheet, transverse flow-guiding microstructure and conical unidirectional flow-guiding micropore.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A zoned, guided, and visualized composite dressing, characterized in that, Includes the absorption area and the visible area, wherein: The absorption area includes a first backing layer, a wound contact layer, and an absorption layer located between the first backing layer and the wound contact layer. The wound contact layer is provided with a first flow guiding structure, which is configured to guide the fluid generated by the skin corresponding to the absorption area unidirectionally to the absorption layer along a first direction. The visible area includes a second backing layer and a transparent gel layer, and the transparent gel layer has a second flow guiding structure on the side close to the skin, which is configured to guide the fluid generated by the skin corresponding to the visible area to the absorption layer of the absorption area in a second direction. Wherein, the first direction refers to a direction substantially from the skin surface to away from the skin surface, and the second direction refers to a direction substantially extending along the skin surface.

2. The zoned drainage visual composite dressing according to claim 1, characterized in that, The first flow guiding structure includes a perforated structure extending along the first direction, and in any longitudinal section along the first direction, the perforated structure includes: The first inclined side has a first endpoint located at the upper part and a second endpoint located at the lower part; The second inclined side has a third endpoint located at the top and a fourth endpoint located at the bottom; Wherein, the first endpoint and the third endpoint are spatially spaced apart, thereby forming a top-side opening distance between the first endpoint and the third endpoint; The second endpoint and the fourth endpoint are spatially spaced apart, thereby forming a bottom opening distance between the second endpoint and the fourth endpoint; The bottom opening and the top opening are opposite each other in the longitudinal direction, and the distance between the top openings is less than the distance between the bottom openings; The hole structure has a structure that runs from top to bottom and is basically frustum-shaped or funnel-shaped.

3. The zoned drainage visual composite dressing according to claim 1, characterized in that, The first flow guiding structure includes a plurality of hole structures, thereby forming a flow guiding hole array, and at least one of the hole structures in the flow guiding hole array includes an anti-backflow annular rolled edge structure, the anti-backflow annular rolled edge structure being formed on the outer periphery of the top side opening of the hole structure and protruding along the top side opening toward the side away from the skin, such that the anti-backflow annular rolled edge structure is entirely located in the external space of the hole structure.

4. The zoned drainage visual composite dressing according to claim 2, characterized in that, The distance from the second endpoint to the fourth endpoint is 100-300 μm, the interior angle formed at the connection between the first inclined side and the second inclined side is 30°-60°, and the distance from the first endpoint to the third endpoint is 20%-45% of the distance from the second endpoint to the fourth endpoint.

5. The zoned drainage visual composite dressing according to claim 1, characterized in that, The wound contact layer includes a hydrophobic base membrane and a skin adhesion layer, and the first flow-guiding structure is disposed on the hydrophobic base membrane.

6. The zoned drainage visual composite dressing according to claim 1, characterized in that, The second flow guiding structure includes microgrooves; The microgrooves include at least one of radial microgrooves, transverse microgrooves, intersecting microgrooves, circumferential microgrooves, and radial microgrooves. The outlet end of the second flow guiding structure extends to the edge of the transparent gel layer and contacts the absorbent layer, thereby forming a continuous capillary flow channel.

7. The zoned drainage visual composite dressing according to claim 1, characterized in that, The second backing layer is a transparent and breathable backing layer; or the first backing layer and the second backing layer are integrally formed.

8. The zoned drainage visual composite dressing according to claim 1, characterized in that, The absorbent layer comprises a polysaccharide nonwoven felt or a cellulose nonwoven felt made of highly absorbent resin.

9. The method for preparing the zoned drainage visual composite dressing according to any one of claims 1-8, characterized in that, Includes the following steps: A first backing layer, a wound contact layer, and an absorbent layer located between the first backing layer and the wound contact layer are provided, and a first flow guiding structure is provided in the wound contact layer to guide the fluid generated by the skin corresponding to the absorbent area unidirectionally to the absorbent layer along a first direction. A second backing layer and a transparent gel layer are provided, and a second flow-guiding structure is provided on the side of the transparent gel layer close to the skin, thereby guiding the fluid generated by the skin corresponding to the visible area to the absorption layer of the absorption area along the second direction; Wherein, the first direction refers to a direction substantially from the skin surface to away from the skin surface, and the second direction refers to a direction substantially extending along the skin surface.

10. The preparation method according to claim 9, characterized in that, The step of setting the first drainage structure in the wound contact layer includes preparing a plurality of porous structures on a hydrophobic base membrane, thereby forming a drainage hole array, and forming an anti-backflow annular rolled edge structure at the top opening of at least one porous structure of the drainage hole array; or The step of setting the second flow-guiding structure on the side of the transparent gel layer near the skin includes pouring hydrogel prepolymer onto a mold or fluorinated release film with a texture on the surface that matches the microgrooves, and obtaining a transparent gel with the second flow-guiding structure on the lower surface after curing and demolding.

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