Medical dressings

Abstract

The present disclosure generally relates to a medical dressing (100) comprising an absorbent foam layer (101) having a first side (101a) and a second side (101b), the medical dressing (100) comprising a support layer (102) facing the first side (101a) of the absorbent foam layer (101) and an adhesive skin-contact layer (103) facing the second side (101b) of the absorbent foam layer (101), the first side (101a) of the absorbent foam layer (101) comprising a plurality of compressed depressions (104a), the support layer (102) being positioned in direct contact with the first side (101a) of the absorbent foam layer (101). The present disclosure also relates to a method of manufacturing the medical dressing.

Description

[Technical Field]

[0001] The present invention relates to a medical dressing having an absorbent foam layer having a first side and a second side, the first side including a plurality of compressed depressions, and to a method of making such a medical dressing. [Background technology]

[0002] Wound healing is a complex process in which destroyed or damaged tissue is replaced by newly produced tissue.

[0003] The wound healing process is typically divided into four stages: hemostasis (blood clotting), inflammation, proliferation (tissue formation), and remodeling (maturation and tissue differentiation). For a wound to heal successfully, all four stages must be achieved. The wound healing process is prone to failure, and destroyed or damaged tissue must be replaced by newly generated tissue.

[0004] Wound assessment is important to assess and ensure the progression of wound healing. Clinicians typically assess a variety of wound characteristics to ensure the wound healing process is progressing appropriately. Factors clinicians typically assess include tissue type, level of exudate, and the color and characteristics of the exudate.

[0005] For example, healthy granulation tissue is pink, a sign of healing. Unhealthy granulation tissue is darker red and often bleeds to the touch, which may indicate a wound infection. Wounds may also be covered with necrotic tissue, identified by black or dark brown exudate, and / or slough, which is yellow. Such tissue impedes the wound healing process.

[0006] Therefore, the characteristics of wound exudate can provide clues regarding the healing potential and progression of the wound and assist clinicians in implementing appropriate treatment strategies.

[0007] Adhesive medical dressings are commonly used in wound care to treat wounds. Such dressings often include an absorbent pad disposed between a support layer and an adhesive skin-contacting layer. The absorbent pad often includes an absorbent foam, such as polyurethane foam.

[0008] Absorbent foams, such as polyurethane foams, are advantageously used to absorb and manage large amounts of wound exudate.

[0009] Absorbent foams have a good ability to transport exudate away from the wound site in a direction perpendicular to the plane of the foam, but typically have a relatively poor ability to spread or distribute the fluid. This can lead to localized saturation of the wound pad, which can result in the need for dressing changes and a shortened dressing wear time.

[0010] Furthermore, absorbent foams, such as polyurethane foams, are typically compact in nature, requiring the dressing to be removed from the skin in order to assess the wound and wound exudate characteristics.

[0011] In view of the above problems, there is a need for improved absorbent foam dressings to improve the fluid handling properties of the dressing and extend the wear time while improving wound assessment procedures. Summary of the Invention [Problem to be solved by the invention]

[0012] In view of the above problems, it is an object of the present disclosure to improve the wound assessment procedure while increasing the wear time of the dressing. [Means for solving the problem]

[0013] According to a first aspect, there is provided a medical dressing comprising an absorbent foam layer having a first side and a second side, the dressing including a support layer facing the first side of the absorbent foam layer and an adhesive skin-contacting layer facing the second side of the absorbent foam layer, the first side of the absorbent foam layer having a plurality of compressed depressions, and the support layer positioned in direct contact with the first side of the absorbent foam layer.

[0014] The plurality of compressed depressions improves the diffusion capacity of the absorbent foam layer, ensuring that blood and wound fluids exuding from the wound are efficiently dispersed within the dressing.

[0015] The support layer is in direct contact with the entire first surface of the absorbent foam layer. Therefore, the support layer conforms to the contours of the compressed cavity. In this way, the surface area of ​​the support layer is significantly increased, allowing exudate to evaporate. Therefore, wound exudate absorbed by the absorbent foam layer can evaporate efficiently through the support layer. Therefore, breathability and water vapor permeability are improved.

[0016] Additionally, direct contact between the first surface of the foam layer and the support layer prevents gaps from forming between the support layer and the "valleys" defined by the compressed depressions. Such gaps can lead to fluid pooling within the dressing, i.e., wound exudate can become trapped in the compressed depression areas instead of distributing from the support layer and evaporating.

[0017] Such a configuration can impair the spreading ability of the dressing and negatively impact the wear time of the dressing. Furthermore, if exudate remains trapped in the region or "valley" between the absorbent foam layer and the support layer, it becomes difficult to visualize the exudate characteristics and identify whether (and when) the exudate characteristics change due to wound infection or wound healing regression.

[0018] Thus, the support layer in direct contact with the compressed depressions of the absorbent foam layer improves visualization of exudate distribution in the wound dressing. The compressed depressions define thinner regions within the absorbent foam, allowing for analysis of wound exudate characteristics.

[0019] In an exemplary embodiment, the support layer is heat laminated to the first side of the absorbent foam layer.

[0020] The support layer is thus melted and fused directly to the first surface of the absorbent foam layer. The heat-laminated support layer forms a thin, continuous layer that extends across the entire first surface of the absorbent foam layer. The heat-laminated support layer conforms to the contours of the compressed depressions in the first surface of the absorbent foam layer.

[0021] The thermally laminated support layer improves the moisture vapor permeability and breathability of the dressing.

[0022] Additionally, the thermal lamination provides a protective function, preventing the ingress of contaminants into the dressing.

[0023] Additionally, the thermally laminated support layer provides a visually and tactilely appealing dressing surface. The support layer blends with the absorbent foam layer to create a soft, appealing texture.

[0024] In an exemplary embodiment, the absorbent foam layer comprises polyurethane foam.

[0025] Polyurethane foam is hydrophilic, porous, and capable of handling large amounts of wound exudate.

[0026] In an exemplary embodiment, the support layer comprises polyurethane.

[0027] Thus, the support layer and the absorbent foam layer are chemically similar, which improves the thermal lamination process by enhancing direct contact between the support layer and the first surface of the absorbent foam layer and allowing the support layer to conform to the contours of the plurality of compressed depressions.

[0028] Preferably, the support layer is a polyurethane film.

[0029] In an exemplary embodiment, the second surface of the absorbent foam layer includes a plurality of compressed depressions that align with the compressed depressions in the first surface of the absorbent foam layer.

[0030] Thus, in areas of the absorbent foam layer where the compressed depressions are located, the foam will be significantly thinner than areas without the compressed depressions.

[0031] This arrangement further enhances the visibility of the color and characteristics of wound exudate, improving the wound assessment procedure for clinicians. Instead of removing the entire dressing from the patient's skin, which would be necessary if the foam was intact or the support layer did not conform to the contours of the compressed cavity, conclusions regarding the progress of wound healing can be drawn while the dressing remains on the patient's skin.

[0032] In exemplary embodiments, the compressed depressions on the first and second sides of the absorbent foam layer are spaced apart by uncompressed regions, and the thickness t1 of the absorbent foam layer in the regions forming the compressed depressions corresponds to 1-20%, preferably 2-10%, more preferably 3-6% of the thickness t2 of the absorbent foam layer in the uncompressed regions.

[0033] This configuration optimizes the balance between efficient exudate distribution and the ability to examine and assess the progress of wound healing.

[0034] The absorbent foam layer is typically white or clear.

[0035] Preferably, the absorbent foam layer is white.

[0036] The white color of the absorbent foam layer improves contrast with the color of the wound exudate, allowing it to be efficiently identified. Therefore, clinicians can easily assess when and how the wound healing process is interrupted. For example, the initial amount of exudate may be visualized as pink, but after a while, a second amount of exudate with a darker color or exudate containing a yellow slough may appear, which usually indicates that the wound healing process has been impaired.

[0037] Of course, a clear foam may allow the same type of visual wound inspection. However, a clear dressing may be perceived as less visually appealing to the patient. Therefore, it is generally desirable to slightly "mask" the wound without compromising the ability to draw conclusions if wound characteristics change.

[0038] In an exemplary embodiment, the support layer has a first surface facing the absorbent foam layer and an opposite second surface, the second surface including a plurality of discrete printed elements regularly arranged across the entire second surface of the support layer.

[0039] The discrete print elements facilitate wound assessment for clinicians and caregivers. For example, clinicians can use the discrete print elements (and compressed depressions) to record the diffusion pattern of wound exudate.

[0040] In embodiments in which the support layer is heat laminated to the first surface of the absorbent foam layer, the first surface of the dressing (i.e., the side facing the clinician) can be used to record wound exudate spread, i.e., spread distance, etc., directly on the top surface of the dressing. Printing elements can be utilized, for example, to record the amount of an initial pink exudate, record the amount of a second exudate of a different color, and record its characteristics.

[0041] Wound exudate records can be used to assess the progress of wound healing and identify whether additional measures are needed to improve wound healing or to prevent or control wound infection.

[0042] Additionally, the printing elements and compressed depressions can be used to cut the dressing as needed.

[0043] Preferably, the size of the discrete print elements is smaller than the size of the compressed depressions on the first surface of the absorbent foam layer.

[0044] This is useful for distinguishing print elements from compressed depressions and utilizing either or both of these features for wound assessment purposes.

[0045] For example, the discrete print elements can be individual printed dots.

[0046] In an exemplary embodiment, the ratio of the plurality of compressed depressions to the discrete print elements on the first surface of the absorbent foam layer is in the range of 1:1-1:7, and preferably in the range of 1:3-1:6.

[0047] The number of compressed depressions is preferably equal to or greater than the number of printing elements.

[0048] Ratios in the above ranges provide a visually appealing impression and facilitate wound inspection and assessment procedures for the clinician.

[0049] In an exemplary embodiment, the second surface of the support layer includes 3-10, preferably 4-7, compressed depressions per square centimeter.

[0050] A compressed depression amount in the above range improves visual wound inspection, improves the liquid spreading ability of the absorbent foam layer (and dressing), and makes the dressing more flexible and conforms to the patient's skin and movements.

[0051] In an exemplary embodiment, the adhesive skin contact layer comprises a silicone-based adhesive.

[0052] Silicone adhesives are gentle on the skin, allowing for painless removal of the dressing from the patient's skin or wound. Additionally, the silicone adhesive ensures that the dressing conforms to the patient's skin.

[0053] In an exemplary embodiment, the adhesive skin-contact layer includes a first silicone gel coating and a second silicone gel coating, the first silicone gel coating being disposed in contact with the second surface of the absorbent foam layer, the first silicone gel coating being a continuous coating, and the second silicone gel coating being a discontinuous coating.

[0054] A first continuous silicone gel coating is applied to the second surface of the absorbent foam layer to render that surface hydrophobic and prevent backflow of wound exudate into the wound site.

[0055] The second discontinuous silicone gel coating improves adhesion to the patient's skin and also allows wound exudate to enter the absorbent foam layer.

[0056] According to another aspect, there is provided a method of manufacturing a medical dressing, comprising the steps of:

[0057] a) providing an absorbent foam layer having a first side and a second side; b) providing a plurality of compressed depressions in a first surface of the absorbent foam layer; c) heat laminating a support layer to the first surface of the absorbent foam layer, positioning the support layer in direct contact with the first surface of the absorbent foam layer; d) providing an adhesive skin contact layer on the second surface of the absorbent foam layer.

[0058] In an exemplary embodiment, the manufacturing method further comprises the following steps.

[0059] Step b') of providing a plurality of compressed depressions on the second surface of the absorbent foam layer, wherein the plurality of compressed depressions coincide with the plurality of compressed depressions on the first surface of the absorbent foam layer, preferably occurring simultaneously with step b) of providing a plurality of compressed depressions on the first surface of the absorbent foam layer.

[0060] In an exemplary embodiment, the manufacturing method further comprises the following steps.

[0061] stretching the absorbent foam layer including the plurality of compressed depressions in step b) and, optionally, in step b') prior to or during step c) of thermally laminating the support surface to the first surface of the absorbent foam layer.

[0062] Further features and advantages of the present disclosure will become apparent from the appended claims and the following description, and those skilled in the art will appreciate that different features of the present disclosure may be combined to form embodiments other than those described below without departing from the scope of the present disclosure. [Brief explanation of the drawings]

[0063] The various aspects of the present disclosure, particularly its features and advantages, will be readily understood from the following detailed description and the accompanying drawings. [Figure 1a] FIG. 1a illustrates a medical dressing according to an exemplary embodiment of the present disclosure. [Figure 1b] FIG. 1b shows an exploded view of a medical dressing according to an exemplary embodiment, showing the support layer separated from the absorbent foam layer. [Figure 2a] FIG. 2a shows an enlarged cross-sectional view of a portion of the medical dressing of FIG. 1a. [Figure 2b] FIG. 2b shows an enlarged cross-sectional view of a portion of a medical dressing that does not form part of the present disclosure, illustrating that the support layer is not in direct contact with the first side of the absorbent foam layer. [Figure 3]FIG. 3 shows two photographs showing the distribution of wound exudate from the support layer of a dressing according to the present disclosure compared to a reference dressing (right photograph). DETAILED DESCRIPTION OF THE INVENTION

[0064] The present disclosure will now be described in more detail with reference to the accompanying drawings, which illustrate presently preferred embodiments of the disclosure. However, the disclosure may be embodied in many different forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided for thoroughness and completeness so as to fully convey the scope of the disclosure to those skilled in the art. Like reference characters refer to like elements throughout.

[0065] 1A, 1B, and 2A conceptually illustrate a medical dressing according to an exemplary embodiment of the present disclosure. The medical dressing 100 includes an absorbent foam layer 101 having a first side 101a and a second side 101b. The dressing 100 includes a support layer 102 facing the first side 101a of the absorbent foam layer 101, and an adhesive skin-contact layer 103 facing the second side 101b of the absorbent foam layer 101. The first side 101a of the absorbent foam layer 101 includes a plurality of compressed depressions 104a, and the support layer 102 is positioned in direct contact with the first side 101a of the absorbent foam layer 101.

[0066] As used herein, the term "medical dressing" refers to a dressing used to treat or prevent any type of wound or injury to a patient's skin. In the context of this disclosure, a medical dressing may also be referred to as a wound dressing if wound exudate is treated by the dressing.

[0067] The wound to be treated can be any type of open or closed wound, such as a chronic wound, an acute wound, a post-operative wound, for example a closed incision or a scar.

[0068] The support layer 102 is placed in direct contact with the entire first surface 101a of the absorbent foam layer 101, and conforms to the contours of the depression 104a into which the support layer is compressed.

[0069] The compressed depressions 104a are preferably arranged in a regular pattern across the first surface 101a of the absorbent foam layer 101.

[0070] As shown in FIGS. 1A and 1B, a plurality of compressed depressions 104a are provided across the first surface 101a of the absorbent foam layer 101.

[0071] This provides a flexible, conformable dressing with improved fluid spreading capabilities. Additionally, the provision of compressed depressions across the first surface allows the flow and distribution of exudate, as well as exudate characteristics (e.g., color, texture), to be visualized and monitored by the caregiver or clinician.

[0072] As best seen in Figure 2A, the support layer 101 is in direct contact with the first surface 101a of the absorbent foam layer 101. As can be seen in this figure, the support layer 101 conforms to the compressed depression 104a. The support layer 101 is positioned to follow the contours of the compressed depression 104a in the first surface 101a of the absorbent foam layer 101. No gaps are formed between the support layer 101 and the first surface 101a of the absorbent foam layer 101.

[0073] In contrast, as shown in Figure 2B, when the support layer is placed by conventional methods, such as with an adhesive, the support layer 102' does not remain in direct contact with and adhered to the first surface of the absorbent foam layer 101' in the areas of the compressed depressions 104a'. Thus, air gaps 107' form in these areas, which can turn into pools of liquid as fluid exudes from the wound site.

[0074] Such fluid accumulation hinders the spreading and distribution of wound exudate within the dressing. Furthermore, it impairs the ability of wound exudate to evaporate from the support layer. Fluid accumulation also hinders visual assessment of wound exudate, preventing clinicians from monitoring the progress of wound healing and drawing conclusions about whether additional treatment measures are required.

[0075] Direct contact with the first surface 101a of the absorbent foam layer 101 significantly increases the surface area of ​​the support layer, allowing exudates to evaporate, improving breathability and moisture vapor permeability.

[0076] Preferably, the support layer 102 is heat laminated to the first surface 101 a of the absorbent foam layer 101 .

[0077] Heat lamination combines the properties of an absorbent foam layer and a support layer. The layers are fused together, eliminating any gaps between the support layer and the absorbent foam layer. Heat and optional pressure are used to bond the two layers together.

[0078] If the support layer is heat laminated to the first surface of the absorbent foam layer, no adhesive is required, which is beneficial because the presence of adhesive between these layers can compromise the breathability of the dressing.

[0079] The absorbent foam layer 101 is typically porous and hydrophilic.

[0080] The absorbent foam layer 101 may comprise a polyurethane foam, preferably a hydrophilic polyurethane foam, which may be porous and contain pores with an average pore size in the range of 30-1000 μm.

[0081] Infected wounds typically exude copious amounts of exudate, and wound pads must be able to adequately manage such exudate.

[0082] Preferably, the support layer comprises polyurethane.

[0083] For example, the support layer may be a polyurethane film, which improves the thermal lamination process because polyurethane film and polyurethane foam are chemically similar to each other.

[0084] The dressings of the present disclosure provide a breathable and highly conformable dressing.

[0085] As best shown in FIG. 2A, the second surface 101b of the absorbent foam layer 101 includes a plurality of compressed depressions 104b that match the compressed depressions 104a in the first surface 101a of the absorbent foam layer 101.

[0086] The compressed depressions 104b on the second surface 101b are generally aligned with the compressed depressions 104a on the first surface 101a of the absorbent foam layer.

[0087] Thus, both the first side 101a and the second side 101b of the absorbent foam layer 101 have grooved surfaces. The surface structure of the first side corresponds to the surface structure of the second side of the absorbent layer (see Figure 2A).

[0088] The compressed depressions 104a, 104b on the first surface 101a and the second surface 101b of the absorbent foam layer 101 are separated from each other by non-compressed regions 105, and the thickness t1 of the absorbent foam layer 101 in the regions forming the compressed depressions 104a, 104b corresponds to 1-20%, preferably 2-10%, more preferably 3-6% of the thickness t2 of the absorbent foam layer in the non-compressed regions 105.

[0089] The thickness t2 of the absorbent foam layer in the non-compressed area may be 2-10 mm, for example 3-6 mm, the thickness being measured in the dry state.

[0090] The thickness t1 of the absorbent foam layer in the area forming the compressed depression may be in the range of 0.05-1.5 mm, for example 0.1-0.5 mm, the thickness being measured in the dry state.

[0091] In areas where the compressed depressions coincide, wound exudate is easily visualized and the spreading pattern and exudate characteristics are monitored.

[0092] Typically, the absorbent foam layer is white or clear.

[0093] Preferably, the absorbent foam layer is white.

[0094] Thus, the contrast between the colored wound exudate and the white foam is improved, allowing for a clear distinction between the color of the wound exudate.

[0095] The adhesive skin contact layer is substantially transparent.

[0096] The support layer may be transparent. In embodiments where the support layer is heat laminated to the absorbent foam layer, the support layer fuses with the foam layer and matches the texture and appearance of the absorbent foam layer.

[0097] As shown in Figures 1A and 1B, the support layer 102 has a first surface 102a facing the absorbent foam layer 101 and an opposite second surface 102b, and the second surface 102b may include a plurality of discrete print elements 106 arranged in a regular pattern across the second surface 102b of the support layer 102.

[0098] The discrete print elements may be pre-printed onto the support layer before the support layer is heat laminated to the absorbent foam layer.

[0099] The discrete print elements may be pre-printed on the first side or the second side of the support layer, but are visible from the second side of the support layer.

[0100] Typically, the size of each of the discrete print elements 106 is smaller than the size of the compressed depressions 104a on the first surface 101a of the absorbent foam layer.

[0101] In Figures 1a and 1b, the discrete print elements 106 are printed dots.

[0102] The dots are preferably arranged in regular rows across the second surface of the support layer.

[0103] Clinicians can therefore use the printed dot pattern to monitor and record the spread of exudate by, for example, counting the printed dots, marking them directly on the surface of the dressing, or drawing lines between the dots to define the distribution of wound exudate, and then analyzing and recording the spread pattern.

[0104] The average distance d1 between adjacent print elements on the first surface of the absorbent foam layer is 0.7-1.7 cm, preferably 0.8-1.3 cm.

[0105] The average distance between adjacent printing elements, e.g., dots, is preferably about 1 cm, which facilitates calculation and recording of the exudate spreading pattern.

[0106] The average distance d2 between adjacent compressed depressions on the first surface of the absorbent foam layer is 0.2-0.7 cm, preferably 0.3-0.6 cm.

[0107] The ratio of the plurality of printing elements 106 to the plurality of compressed depressions 104a on the first surface 101a of the absorbent foam layer 101 is 1:1-1:7, preferably 1:3-1:6.

[0108] Ratios in the above ranges provide a visually appealing impression and facilitate wound inspection and assessment procedures for the clinician.

[0109] In an exemplary embodiment, the second surface of the support layer has 3-10, preferably 4-7, compressed depressions per square centimeter.

[0110] A compressed depression amount in the above range improves visual wound inspection and also improves the liquid spreading ability of the absorbent foam layer (and dressing).

[0111] Additionally, the dressing becomes more flexible and drapeable, conforming to the patient's skin and movements.

[0112] Preferably, the adhesive skin contact layer 103 comprises a silicone based adhesive.

[0113] Silicone adhesives are gentle and soft, allowing for atraumatically removing the dressing from the patient's skin or wound.

[0114] The adhesive skin contact layer 103 is typically coated onto the second surface 101b of the absorbent foam layer. The adhesive skin contact layer is in direct contact with the second surface of the absorbent foam layer. Therefore, no gaps form in the dressing that could trap fluid.

[0115] The adhesive skin-contact layer 102 can include a first silicone gel coating and a second silicone gel coating, the first silicone gel coating being disposed in contact with the second surface 101b of the absorbent foam layer 101, the first silicone gel coating being a continuous coating, and the second silicone gel coating being a discontinuous coating.

[0116] The first silicone gel coating is a continuous coating and is applied directly to the second surface of absorbent foam layer 101b. In addition to providing adhesive contact to the skin and / or wound, the first silicone gel coating can also render the hydrophilic absorbent foam layer hydrophobic, which is beneficial for preventing backflow of wound exudate into the wound site.

[0117] The second silicone gel coating is discontinuous and applied over the first silicone gel coating to improve adhesion to the patient's skin and facilitate the passage of wound exudate into the absorbent foam layer.

[0118] According to another aspect, there is provided a method of manufacturing a medical dressing 100 comprising the steps of: a) providing an absorbent foam layer 101 having a first surface 101a and a second surface 101b; b) providing a plurality of compressed depressions 104a on the first surface 101a of the absorbent foam layer 101; c) heat laminating a support layer 102 to the first surface 101a of the absorbent foam layer 101, and placing the support layer 102 in direct contact with the first surface 101a of the absorbent foam layer 101; d) providing an adhesive skin contact layer 103 on the second surface 101b of the absorbent foam layer 101;

[0119] Preferably, the absorbent foam layer 101 comprises polyurethane foam, which can be provided by means known to those skilled in the art.

[0120] Providing the plurality of compressed depressions 104a on the first surface 101a of the absorbent foam layer is not limited to a particular technique, and any technique can be utilized.

[0121] Preferably, the method further comprises the following steps: b') providing a plurality of compressed depressions 104b on the second surface 101b of the absorbent foam layer 101, the plurality of compressed depressions 104b corresponding to the plurality of compressed depressions 104a on the first surface 101a of the absorbent foam layer 101, preferably simultaneously with step b) of providing a plurality of compressed depressions 104a on the first surface 101a of the absorbent foam layer 101.

[0122] The compressed depressions on the first and second surfaces of the absorbent foam layer can be provided by feeding the absorbent foam layer between opposing rollers having a pattern of protrusions protruding from their outer surfaces and the horn of an ultrasonic welding device.

[0123] The support layer 102 may be applied to the first surface 101 a of the absorbent foam layer 101 by thermal lamination, and positioned so that the support layer 102 is in direct contact with the first surface 101 a of the absorbent foam layer 101 .

[0124] The support layer 102 is typically thin and can be applied to the absorbent foam layer 101 with the aid of a roller. The support layer can then be heated to a temperature at which it melts to form a continuous layer on the absorbent foam layer and conforms to the contours of the first side of the absorbent foam layer.

[0125] Preferably, the method further comprises the following steps: Stretching the absorbent foam layer 101, the absorbent foam layer 101 comprising a plurality of compressed depressions formed in step b) and optionally in step b') prior to or during step c) of thermally laminating the support layer 102 to the first surface 101a of the absorbent foam layer 101.

[0126] The absorbent foam layer 101 can be stretched by 5-30%, for example 15-25%, in the transverse (x) and longitudinal (y) directions.

[0127] This provides an excess amount of support layer material when the absorbent foam layer subsequently shrinks, preventing pinholes in the support layer and thus achieving a continuous, protective support layer that conforms to the first surface of the absorbent foam layer.

[0128] The adhesive skin contact layer typically comprises a silicone adhesive and may be coated, for example, by transfer coating, onto the second surface of the absorbent foam layer.

[0129] (Example 1: Preparing medical dressings) An absorbent foam layer according to the present disclosure is prepared from a web of uncompressed polyurethane foam, the uncompressed PU foam having a thickness of about 5 mm. The uncompressed PU foam is fed between an ultrasonic horn and opposing rollers having a pattern of protrusions protruding from their outer surfaces to form a plurality of compressed depressions.

[0130] The horn moves towards and away from the opposing roller at ultrasonic frequencies. Internal friction therefore generates heat in the material. This heat is then concentrated in the foam placed between the horn and the tips of the projections on the opposing roller. The energy delivered by the ultrasonic welding device is so high that the material between the tips of the projections and the horn fuses together, ensuring that no cells or very small cells remain in these parts of the web after the compression step by the ultrasonic welding device.

[0131] A polyurethane film is then heat-laminated to the first surface of the absorbent foam layer. After the polyurethane film is applied, the dressing substrate is fed between two rolls, with the roll facing the support layer heated to 140°C. The support layer and absorbent layer are pressed together, melting the polyurethane film to form a continuous support layer that conforms to the shape of the compressed depressions on the first surface of the absorbent foam pad layer. The absorbent foam layer remains stretched during the heat-lamination process.

[0132] An adhesive silicone gel layer is then applied to the second surface of the absorbent foam layer by transfer coating.

[0133] (Example 2: Visualization of wound exudate) A simulated controlled trial was conducted to evaluate the effectiveness of the dressing in facilitating wound examination.

[0134] A dressing prepared according to Example 1 (hereafter referred to as Dressing A) is compared to a foam dressing with similar ingredients. The compared dressing (hereafter referred to as Dressing B) differs from Dressing A in that the polyurethane foam is not compressed. Instead, the absorbent foam layer used is 5 mm thick uncompressed polyurethane foam.

[0135] The dressing sample is placed on a flat support surface. The flat support surface contains a central hole. The dressing sample is positioned over the hole in the support surface. Tubing is attached to the center of the dressing sample (through the hole). The tubing is connected to a syringe pump, and 2.5 ml of red ink (representing the first exudate volume) is pumped into the dressing at a rate of 0.5 ml / min. After 50 seconds, blue ink (representing the second exudate volume) is pumped into the dressing at a rate of 0.5 ml / min. The total volume of blue ink is 1 ml.

[0136] With the dressing of the present disclosure (Dressing A), different colored fluids are easily distinguishable and the degree of distribution can be assessed (see photo on the left). With Dressing B, different colored fluids are difficult to distinguish, significantly hindering visual inspection of exudate color and distribution (see photo on the right).

[0137] The terms, definitions and embodiments of all aspects of this disclosure apply mutatis mutandis to the other aspects of this disclosure.

[0138] Although the present disclosure has been described with reference to specific exemplary embodiments, many different alterations, modifications and the like will become apparent to those skilled in the art.

[0139] Variations of the disclosed embodiments can be understood and effected by those skilled in the art in practicing the present disclosure, from a study of the drawings, the disclosure, and the appended claims. Moreover, in the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

Claims

1. A medical dressing (100) having an absorbent foam layer (101), The absorbent foam layer (101) has a first surface (101a) and a second surface (101b); The medical dressing (100) comprises a support layer (102) facing the first side (101a) of the absorbent foam layer (101), and an adhesive skin-contact layer (103) facing the second side (101b) of the absorbent foam layer (101); the first surface (101a) of the absorbent foam layer (101) comprises a plurality of compressed depressions (104a); A medical dressing (100), wherein the support layer (102) is positioned in direct contact with the first surface (101a) of the absorbent foam layer (101).

2. 2. The medical dressing (100) of claim 1, wherein the support layer (102) is thermally laminated to the first surface (101a) of the absorbent foam layer (101).

3. 3. The medical dressing (100) of claim 1 or 2, wherein the absorbent foam layer (101) comprises polyurethane foam.

4. The medical dressing (100) of any one of claims 1 to 3, wherein the support layer (102) comprises polyurethane.

5. 5. The medical dressing (100) of claim 1, wherein the second surface (101b) of the absorbent foam layer (101) comprises a plurality of compressed depressions (104b) that align with the compressed depressions (104a) of the first surface (101a) of the absorbent foam layer (101).

6. the compressed depressions (104a, 104b) on the first surface (101a) and the second surface (101b) of the absorbent foam layer (101) are spaced apart from each other by uncompressed regions (105); 6. The medical dressing (100) of claim 5, wherein the thickness t1 of the absorbent foam layer (101) in the areas forming the compressed depressions (104a, 104b) corresponds to 1-20%, preferably 2-10%, more preferably 3-6% of the thickness t2 of the absorbent foam layer in the non-compressed areas (105).

7. The medical dressing (100) of any one of claims 1 to 6, wherein the absorbent foam layer is white or transparent.

8. The support layer (102) has a first surface (102a) facing the absorbent foam layer (101) and an opposite second surface (102b), 8. The medical dressing (100) of claim 1, wherein the second surface (102b) comprises a plurality of discrete print elements (106) arranged in a regular pattern across the second surface (102b) of the support layer (102).

9. 9. The medical dressing (100) of claim 1, wherein the size of each of the discrete print elements (106) is smaller than the size of the compressed depressions (104a) on the first surface (101a) of the absorbent foam layer.

10. 10. The medical dressing (100) of claim 8 or 9, wherein the ratio of the plurality of discrete print elements (106) to the plurality of compressed depressions (104a) on the first surface (101a) of the absorbent foam layer (101) is 1:1-1:7, preferably 1:3-1:

6.

11. A medical dressing (100) according to any one of claims 1 to 10, wherein the second surface (102b) of the support layer (102) comprises 3-10, preferably 4-7 compressed depressions per square centimetre.

12. A medical dressing (100) according to any one of claims 1 to 11, wherein the adhesive skin contact layer (103) comprises a silicone-based adhesive.

13. the adhesive skin-contact layer (103) comprises a first silicone gel coating and a second silicone gel coating, the first silicone gel coating being disposed in contact with the second surface (101b) of the absorbent foam layer (101); 13. The medical dressing (100) of any one of claims 1-12, wherein the first silicone gel coating is a continuous coating and the second silicone gel coating is a discontinuous coating.

14. A method for manufacturing a medical dressing (100), comprising: a) providing an absorbent foam layer (101) having a first surface (101a) and a second surface (101b); b) providing a plurality of compressed depressions (104a) on said first surface (101a) of said absorbent foam layer (101); c) heat laminating a support layer (102) to the first surface (101a) of the absorbent foam layer (101), the support layer (102) being placed in direct contact with the first surface (101a) of the absorbent foam layer (101); d) providing an adhesive skin contact layer (103) on said second surface (101b) of said absorbent foam layer (101).

15. The manufacturing method further comprises the steps of:

15. A method according to claim 14, comprising a step b') of providing a plurality of compressed depressions (104b) on the second surface (101b) of the absorbent foam layer (101), the plurality of compressed depressions (104b) coinciding with the plurality of compressed depressions (104a) on the first surface (101a) of the absorbent foam layer (101), preferably simultaneously with step b) of providing the plurality of compressed depressions (104a) on the first surface (101a) of the absorbent foam layer (101).

16. The manufacturing method further comprises the steps of:

16. The method of claim 14 or 15, further comprising the step of stretching the absorbent foam layer (101) comprising the plurality of compressed depressions in step b) and optionally in step b') before or during step c) of thermally laminating the support layer (102) to the first side (101a) of the absorbent foam layer (101).

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