Absorbent material for wound bandages and method for manufacturing the same

Abstract

This specification provides absorbent materials for wound dressings, dressings including absorbent pads, and methods for manufacturing absorbent pads. The absorbent pad comprises a first layer containing a polymer, such as an extruded open polymer film, and a second layer heat-bonded to the first layer. The second layer comprises at least one heat-bondable fiber, such as a two-component fiber having at least one first material having a higher melting point than the second material. The first and second layers are bonded to each other such that the three-dimensional structure and inherent porosity of the polymer mesh are substantially maintained, resulting in a two-layer absorbent pad with improved absorbency and enhanced wicking ability.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 489,161, filed on March 8, 2023, the entire disclosure of which is hereby incorporated by reference herein for all purposes. Technical Field This disclosure generally relates to wound dressings such as bandages, and more particularly, to absorbent materials for wound dressings and methods of manufacturing the same.

Background Art

[0002] Absorbent materials are used in wound care to protectively cover the wound site, absorb moisture and exudate, and promote healing. Such materials generally include a non - woven fabric including at least one fluid - permeable layer for contact with the surface of the healing wound. Conventionally, the non - woven fabric constituting the absorbent pad used in bandages contains thermoplastic polymer fibers to give strength to the pad. This material can be fibrous, porous, natural or synthetic. Preferred fibers are synthetic resin fibers, particularly olefin - based fibers such as polyethylene, polypropylene, or blends, and the absorbent article can include other materials such as polyester, rayon, cotton, or blends thereof. Polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polylactic acid are used in the art. One of the main goals in the art is to maintain a relatively thin material that is cost - effective and comfortable to use while improving the absorbency and wicking ability of the absorbent pad. Determining the optimal fiber material, fiber arrangement, and configuration of these fiber layers can be difficult because the efficiency of absorbent articles is reduced by certain aspects of the manufacturing processes currently used in the art. For example, depending on the layer configuration and raw material selection, the adhesive strength may be weakened, thereby compromising the structural integrity of the absorbent article. As a result, absorbency may be insufficient and delamination between fabric layers may occur.

[0003] In one example of such a conventional absorbent pad, a layer of nonwoven polymer mesh is bonded to a layer of polyethylene terephthalate (PET) fibers. To ensure proper adhesion of the polymer materials, the fiber layer is typically subjected to hot rolling and pressure rolling using calender rollers in a method called calendering, which compresses and welds the layer at high speed. Heat and pressure are applied at the calendering point of the calender roll through which the fabric passes. High-pressure calendering is highly effective for polymer fusion, but the continuous mechanical impact on absorbent materials can damage or collapse the structure of the article, such as the three-dimensional structure of nonwoven polymer mesh. The force of the calender rollers can also destroy the inherent porosity of porous polymer mesh. These holes are formed by spaces and gaps within the three-dimensional arrangement of fibers, or by openings formed therein. As a result, these holes can deform during the pressing process. This is particularly counterproductive because the openings, with their uniform shape, give the article a consistent pattern, and the shape and spacing of each opening are tailored to the application. For example, the uniform shape of the openings within the absorbent pad of a bandage ensures that no "dead spots" occur between layers during use, thus preventing fluid flow from being obstructed by areas of irregular structure in the absorbent article and preventing obstruction of respiration at specific wound sites. If the structure of the absorbent pad is collapsed or irregular within its structure, the channels for water, blood, sweat, and secretions within the film become blocked. Furthermore, irregularly spaced openings may prevent water vapor from being evenly and uniformly expelled throughout the wound, potentially increasing the risk of wound maceration. [Overview of the project]

[0004] High-pressure calendering alters the properties of absorbent articles, the nature of their openings, and the wicking pattern, thus reducing the overall absorbency of the article. Therefore, it is desirable to provide an improved absorbent material for wound dressings that includes a thin polymer layer that can be bonded without destroying the three-dimensional structure of the material or impairing the porosity of the article, thereby improving the overall absorbency of the wound dressing.

[0005] The following is a simplified overview of the claimed subject matter to provide a basic understanding of some aspects of the claimed subject matter. This overview is not a comprehensive overview of the claimed subject matter. This overview is not intended to identify any important or essential elements of the claimed subject matter, nor to define the scope of the claimed subject matter. Its sole purpose is to present some concepts of the claimed subject matter in a simplified form as a preliminary step to the more detailed explanation that follows.

[0006] This specification provides absorbent pads for wound dressings and methods for manufacturing such absorbent pads. The absorbent pad comprises a highly absorbent polymer composition, which is designed using fibers and polymers arranged and bonded without substantially destroying the three-dimensional structure or porosity of the material. The absorbent pad can be used, for example, as a layer in a dressing that comes into contact with a wound. The dressing may also include at least one other layer, such as an adhesive layer. Alternatively, the absorbent article can be used as a dressing material itself. The absorbent composition is used to treat wounds such as abrasions, cuts, punctures, and burns, but is not limited to these. In one embodiment, an absorbent pad for a wound dressing comprises a first polymer layer and a second layer heat-bonded to the first layer and containing at least one type of heat-bondable fiber. The selection of polymer fibers and their arrangement in the two layers disclosed herein is advantageous in that the composite pad is lightweight and highly absorbent. In addition, since the first and second layers can be heat-bonded to each other, a high-pressure calendering process is not required in the manufacture of the absorbent pad. Thus, the three-dimensional structure and inherent porosity of the absorbent pad are substantially maintained, resulting in a two-layer absorbent pad with improved absorbency and enhanced wicking ability.

[0007] In several embodiments, the heat-bondable fibers include biocomponent fibers having at least two different materials. The binary fibers may be continuous (e.g., high loft) or discontinuous. The biocomponent fibers may include any preferred configuration such as core / sheath with concentric or eccentric cores, side-by-side, split pipe, sea-island type, hollow binary fibers, hollow split pipe, trefoil binary fibers, mixed fibers, striped fibers, conductive fibers, etc. The binary fibers may have a solid or hollow core. In several embodiments, the two-component fiber comprises a first polymer material and a second polymer material. The second polymer material has a lower melting temperature than the first polymer material.

[0008] In one exemplary embodiment, the two-component fiber comprises a core and a sheath. The core may be concentric or eccentric with the sheath. The core comprises a first material, and the sheath comprises a second material. The second material has a lower melting temperature than the first material. In another embodiment, the first material has a lower melting temperature than the second material. The core may comprise any suitable material such as polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof. In one exemplary embodiment, the core comprises PET. The sheath may include any suitable material such as polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof. In one exemplary embodiment, the sheath includes PE.

[0009] In one exemplary embodiment, the two-component fiber includes a PET core surrounded by a PE sheath. The arrangement of the PET core and PE sheath provides a composition that can be easily bonded, for example, by utilizing thermal bonding due to the difference in melting temperatures of the two components. In addition, the method of bonding the fiber layer to the first polymer layer adjacent to the fiber layer can employ a type of bonding that does not require high-pressure mechanical force. Ultimately, these materials, their composition and processing eliminate the need for bonding techniques that destroy the three-dimensional structure of the composite material, allowing the article to operate with greater efficiency. In several embodiments, the core-to-sheath mass ratio is approximately 30 / 70 to approximately 70 / 30, preferably approximately 40 / 60 to approximately 60 / 40. Within this range, the optimal overall density of the absorbent pad is maintained. Density is an important consideration for absorbent pads; if the value is too high or too low, the pad may become uncomfortable or weak and ineffective. In some embodiments, the polyethylene sheaths are randomly arranged within a second layer. Alternatively, the polyethylene sheaths may be arranged adjacent to one another. In other embodiments, the sheaths may include single-layer or multi-layer sheaths. In some embodiments, the sheaths are arranged in a structured pattern of intersecting sheaths. In another embodiment, the binary fiber may have a configuration that includes side-by-side, split pie, sea-island type, hollow binary fiber, hollow split pie, trefoil binary fiber, mixed fiber, stripe fiber, conductive fiber, and the like. The binary fiber may have a solid or hollow core. The binary fiber comprises at least a first polymer and a second polymer having different melting temperatures and a mass ratio of about 20 / 80 to about 80 / 20.

[0010] In several embodiments, the second layer further comprises at least one type of non-heat-adhesive fiber. The non-heat-adhesive fiber has a melting point at least about 5°C, or at least 15°C, higher than the melting point of the heat-adhesive fiber. In one exemplary embodiment, the non-heat-adhesive fiber has a melting point higher than the melting point range (i.e., the “paste range”) of the heat-adhesive fiber, such that the heat-adhesive fiber is completely melted before the non-heat-adhesive fiber begins to melt. The non-heat-bondable fibers may include any suitable material such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or combinations thereof. For example, if HDPE is selected for the sheath, the non-bondable fibers may be PET. Non-adherent fibers may have any suitable cross-section, such as circular, non-circular, irregular, 4DG, trefoil, or ribbon shapes. Non-circular fibers have a larger specific surface area, resulting in greater liquid absorption. Non-heat-adherent fibers may include two-component fibers. In several embodiments, the non-heat-adherent fibers constitute 50% by mass or less of the second layer, preferably 40% by mass or less of the second layer. In some embodiments, the fibers within the second layer include a spin finish. The spin finish is selected from FDA-approved hydrophilic or hydrophobic spin finishes (for skin contact). Preferably, a hydrophilic spin finish is selected to increase liquid absorption capacity. However, it should be recognized that the spin finish may be an FDA-unapproved spin finish as long as it does not harm the skin. The spin finish content is 2% or less.

[0011] In several embodiments, the absorbent pad includes a third polymer layer. The second layer may be positioned between the first and third layers. Alternatively, the second layer may be heat-bonded to the third layer. In several embodiments, the first and / or third layer comprises a polymer film or mesh. Suitable films or meshes include open films, perforated films, polymer meshes, microporous films, and nets. The mesh or film may also include nonwoven materials, woven materials, and knitted materials. In one exemplary embodiment, the polymer film comprises an extruded film having openings. The openings may include holes or perforations and may have any suitable shape, such as hexagonal, square, rhombus, circular, elliptical, triangular, rectangular, or a combination thereof. Suitable materials for the extruded film include polypropylene, polyethylene, high-density polyethylene (HDPE), or a combination thereof. In some embodiments, the absorbent pad has a thickness of about 40 mil to about 200 mil, preferably about 100 mil to about 130 mil. Within this range, stronger affinity adhesion is obtained and the amount of raw materials required is reduced, thus lowering the increase in manufacturing costs of the absorbent pad. In certain embodiments, the absorbent pad has an absorbency of approximately 5 g / g to approximately 100 g / g, or approximately 5 g / g to approximately 40 g / g, or approximately 10 g / g to approximately 20 g / g.

[0012] The fibers can be manufactured by any suitable method, including, but not limited to, meltblown, spunbond or spunlace, two-component spunbond, heat bonding, carding, air-laid, wet-laid, extrusion, co-molding, needle punching, stitching, and water-flow entanglement. In one embodiment, the fibers are carded and heat-bonded to produce a web. The fiber absorbency is approximately 10 g / g to 20 g / g or approximately 14 g / g to 16 g / g, and the basis weight is approximately 80 gsm to 90 gsm.

[0013] In another embodiment, fibers are spunbonded by bonding extruded spun filaments together to form a web. The spunbonding method is more cost-effective than other fiber manufacturing methods and has the potential to increase manufacturing efficiency by improving throughput, reducing maintenance, saving space, facilitating automation, lowering scrap rates, and enabling continuous manufacturing processes (i.e., 24 hours a day, 7 days a week). In certain embodiments, the spunbond fibers may be continuous or formed directly from the resin. In other embodiments, the spunbond fibers are staple fibers. The fibers may be bare (i.e., zero-spin finish) before coating. The fibers may undergo a spin finish before coating. In certain embodiments, the conventional spin finish of staple fibers is less than 2%.

[0014] In an exemplary embodiment, spunbond fibers are coated with a silicone-based coating to enhance the absorbency of the pad. The coated spunbond fibers are then heat-bonded to a first polymer layer. The added mass of the silicone-based coating may be about 1.0 gsm to about 20 gsm, or about 1.5 gsm to about 15.5 gsm. In an exemplary embodiment, the coated spunbond fibers have an absorbency of about 5 g / g to about 20 g / g, or about 10 g / g to about 12 g / g. The basis weight of the coated spunbond fibers is lower than that of the carded fibers, or may be about 60 gsm to about 75 gsm. In various embodiments, the silicone coating comprises a silicone compound diluted with water or another suitable fluid, such that the silicone compound constitutes at least about 2% by mass of the coating, or at least about 5% by mass of the coating. In one exemplary embodiment, the silicone compound constitutes about 10% by mass of the coating. In various embodiments, the silicone coating comprises a reactive silicone macroemulsion. The silicone emulsion may include, for example, dimethyl silicone emulsion, amino-type silicone emulsion, organically functional silicone emulsion, resin-type silicone emulsion, and film-forming silicone emulsion. In one embodiment, the reactive silicone macroemulsion comprises amino-modified polydimethylsiloxane and / or polyethylene glycol monotridecyl ether. In an exemplary embodiment, amino-modified polydimethylsiloxane constitutes about 30 to about 40% by mass of the coating. In several embodiments, polyethylene glycol monotridecyl ether constitutes about 5 to about 10% by mass of the coating. In some embodiments, the silicone coating further includes an antistatic agent. Examples of antistatic agents include cationic antistatic agents, anionic antistatic agents, quaternary antistatic agents, or surfactants. Examples of surfactants include non-re-wetting, pyrolytic surfactants / foaming agents. In various embodiments, silicone-based coatings are applied by any preferred method, including, but not limited to, spraying a silicone-based coating agent onto fibers, immersing fibers in a container of silicone-based coating agent, applying the silicone-based coating agent to fibers in foam form, using a measuring rod or other leveling device to apply the coating agent, supplying the coating agent onto fibers using a coating head such as a slot die, or any combination of these techniques. The coating can be applied as a spin finish or after a spin finish. The coating can also be applied to bare fibers that have not been spin-finished. The coating can also be applied to staple fibers that have already undergone a typical spin finish.

[0015] In another embodiment, the bandage is provided comprising an adhesive layer and an absorbent pad. The absorbent pad is bonded to the adhesive layer and may extend over at least a portion of the adhesive layer. The absorbent pad comprises a first layer and a second layer. The first layer of the absorbent pad comprises a polymer and a second layer which is heat-bonded to the first layer and comprises at least one type of heat-bondable fiber. The first layer may include a polymer film as described above. The second layer may include any of the embodiments described above. The absorbent pad may include a third layer such that the second layer is positioned between the first and third layers. In addition to the adhesive and absorbent layer, the bandage may also include other layers such as a padding layer, a release layer, and others known in the art. In another embodiment, a method for manufacturing an absorbent pad for wound dressings is provided. This method includes providing a first polymer layer and a second fiber layer, and heat-bonding or laminating the first layer to the second layer.

[0016] In several embodiments, the method further comprises forming a first layer from an extruded polymer film and forming a plurality of openings in the extruded polymer film. These openings may be formed by mechanical embossing, stretch breaking, vacuum forming, hydroforming, hydrocutting, needle punching, ultrasonic, slitting, ring rolling, and any combination thereof. These openings may be formed before bonding the first and second layers, simultaneously with the bonding of these layers, or as a finishing step after bonding. The opening formation step may be used, if necessary, to enhance the absorbency and extensibility of the absorbent material. The absorbent pad of the bandage is a thin, absorbent two-layer structure processed without the use of high-pressure calendering, thereby substantially maintaining the material's three-dimensional structure and porosity. The individual shapes of these openings and their uniformity throughout the entire pad layer of the bandage are precisely and well maintained by the pad's fiber and two-layer structure, high-precision cutting using ultrasound, and the absence of calendering pressure during manufacturing.

[0017] In several embodiments, the method further includes thermally bonding a second layer to a third layer comprising an extruded polymer opening film. The second layer may be positioned between the first and third layers. This method may include a second bonding step, which may include thermal bonding, chemical bonding, ultrasonic bonding, embossing, and any combination thereof. The second layer preferably comprises one or more heat-adhesive fibers. The method may further include providing at least one heat-non-adhesive fiber in the second layer. The heat-non-adhesive fiber has a first melting point, which is at least about 15°C higher than the second melting point of the heat-adhesive fiber. In some embodiments, the method includes arranging heat-bondable fibers in a second layer in a core-sheath configuration to form a two-component fiber. In one exemplary embodiment, PET forms the core and polyethylene forms the sheath. The method may further include configuring the polyethylene sheath in a substantially structured pattern of randomly or intersecting sheaths within the second layer. Furthermore, the method may include configuring the sheath to be single-layer or multi-layer.

[0018] It should be understood that both the above general description and the following detailed description are for the purpose of illustration and explanation only, and are not limiting. Additional features will be described in part in the following description or will be known by practicing this description. The accompanying drawings, which are incorporated herein and constitute a part hereof, illustrate some embodiments of the present disclosure and serve to explain the principles of the present disclosure together with the description.

Brief Description of the Drawings

[0019] [Figure 1A] FIG. 1A is a perspective top view of a bandage having an adhesive layer and an absorbent pad. [Figure 1B] FIG. 1B is a cross-sectional view of a bandage having an absorbent pad, an adhesive layer, and an additional layer. [Figure 2] FIG. 2 is a cross-sectional view of one embodiment of an absorbent pad. [Figure 3] FIG. 3 is a perspective view of one embodiment of the two-component fibers of the absorbent pad of FIG. 2.

Modes for Carrying Out the Invention

[0020] This specification and the accompanying drawings illustrate exemplary embodiments and should not be taken as limiting, and the scope of this specification, including equivalents, is defined by the claims. Various mechanical, compositional, structural, and operational modifications can be made without departing from the scope of this specification and the claims, including equivalents. In some cases, well-known structures and techniques are not shown or described in detail to avoid obscuring the explanation. Similar numbers in two or more figures represent identical or similar elements. Furthermore, elements and their related aspects described in detail with respect to one embodiment may, at any time, be included in other embodiments that are not specifically shown or described, where it is practically possible. For example, if an element is described in detail with respect to one embodiment but not with respect to a second embodiment, it can still be argued that the element is included in the second embodiment. Furthermore, the descriptions in this specification are for illustrative purposes only and do not necessarily reflect the actual shape, size, or dimensions of the system or illustrated components. When used herein and in the appended claims, the singular forms “a,” “an,” and “the,” as well as the singular form of any word, should be noted to include multiple referents unless explicitly and obviously limited to one referent. When used herein, the term “include” and its grammatical variations are intended to be non-restrictive, and the enumeration of items in a list does not exclude other similar items that may be substituted for or added to the listed items.

[0021] The following describes an absorbent pad for use with a bandage, but it should be understood that the features described herein can be readily adapted for use in wound care in various methods known in the art. For example, the absorbent article may be formed as a bandage to wrap a wound. The absorbent article may be configured to contact the entire longitudinal surface of the wound and may be held in place by an adhesive that does not extend to the surface of the pad opposite the skin. For example, only the outer edge of the pad may be fixed to the skin using an adhesive or other technique. Furthermore, it should be understood that the terms “absorbent pad” and “pad” as used herein and in the appended claims do not limit the use of the absorbent articles they refer to to mere padding that functions as a buffer or filler between other layers. In fact, the terms may also broadly refer to thin, flat, fibrous materials such as the absorbent layer of a bandage known in the art.

[0022] This specification provides absorbent pads and bandages for application to wounds. It should be understood that the absorbent pads and bandages are intended for the treatment of all types of damage or openings in epithelial tissue, such as skin. For example, wounds may be abrasions, scratches, scabs, blisters, burns, incisions, lacerations, punctures, or peels, and the absorbent material can be applied to the wound bed or closing tissue during healing. The absorbent material can also be used for erosions, ulcers, and infected skin. Typical fluids that flow from a wound into one or more layers of the absorbent pad include blood and its components, sweat, serous fluid, and pus. This material can be used for wounds of any size, shape, or depth, and in clinical settings.

[0023] Figures 1A and 1B show an exemplary bandage 2 having an adhesive layer 8 and an absorbent pad 10. Additional layers, such as a backing layer 6, may also be layers of bandage 2. Bandage 2 may include one or more additional layers (not shown), or multiple layers of any of those shown in Figure 1. In certain embodiments, a wound release layer (not shown) may be added to the surface of the absorbent pad 10 that comes into contact with the wound. For example, a porous net may be placed between the wound and the absorbent pad 10 to facilitate the removal of the pad and / or bandage. Other types of backing or release layers may be added, and it is understood that layers relating to easy removal of the pad or bandage from its packaging may be included. Alternatively, a release layer, such as a silicone paper release strip (not shown), may be present on the surface of the adhesive layer 8, which can be removed by the user before the bandage is placed on the skin. In certain embodiments, the adhesive layer 8 is placed on healthy tissue just outside the wound boundary. The adhesive layer 8 may be further separated from the skin by another layer that acts as a skin barrier for people allergic to certain adhesives, for example. In other embodiments of the absorbent pad 10, allergies to the adhesive material can also be avoided by using the absorbent pad 10 as a bandage to wrap the wound rather than using it as a bandage 2, as described above. The adhesive layer 8 or backing layer 6 of the bandage 2 can be of any thickness. In some embodiments, the backing layer 6 has a thickness in the range of about 1 to 4 mils. In other embodiments, these layers may each be less than 1 mil thick. In some embodiments, another adhesive layer may be present between the absorbent pad 10 and the backing layer 6. Alternatively, the adhesive may be applied directly to the surface of the absorbent pad 10 adjacent to the backing layer 6 before joining the two layers in forming the bandage 2.

[0024] Referring now to Figure 2, one embodiment of the absorbent pad 10 is shown in cross-section with the first layer 20 and the second layer 30 separated. Naturally, it should be understood that the separation of these layers shown in Figure 2 is merely to clarify the characteristics of the absorbent pad 10 and does not mean that these layers will separate during use or remain separated in the final product. The first layer 20 contains a polymer, and the second layer 30 contains at least one type of heat-bondable fiber. The first layer 20 and the second layer 30 are heat-bonded to each other to form a lightweight and highly absorbent pad. The absorbent pad 10 has a thickness of about 40 mil to about 200 mil, preferably about 100 mil to about 130 mil. Within this range, stronger affinity bonding is obtained and the amount of raw materials required is reduced, thus reducing the increase in manufacturing costs of the absorbent pad. The absorbent pad 10 of the bandage 2 exhibits high absorbency due to its unique structure. For example, the absorbent pad 10 may have an absorbency of about 5 g / g to 100 g / g or about 5 g / g to about 40 g / g, preferably about 10 g / g to about 20 g / g. In certain embodiments, the fibers are carded and then air-through or heat-bonded to produce a web. In these embodiments, the fibers may have an absorbency of about 10 g / g to about 20 g / g, or about 14 g / g to about 16 g / g. In other embodiments, the fibers may be spunbonded and coated with a silicone-based coating (described later). The added mass of the silicone-based coating is about 1.0 gsm to about 20 gsm, or about 1.5 gsm to about 15.5 gsm. In one exemplary embodiment, the coated spunbonded fibers have an absorbency of about 5 g / g to about 20 g / g, or about 10 g / g to about 12 g / g.

[0025] In several embodiments, the absorbent pad 10 includes a third polymer layer (not shown). A second layer 30 may be positioned between the first and third layers. The second layer 30 may also be heat-bonded to the third layer. The absorbent pad 10 may include an additional polymer layer and / or an additional fiber layer. The first layer 20 and the third layer preferably include a polymer film or mesh. Suitable films or meshes include open films, perforated films, polymer meshes, microporous films, and nets. The mesh or film may also include nonwoven fabrics, woven fabrics, knitted fabrics, and other materials.

[0026] In one embodiment, the polymer film layer comprises an extruded opening polymer sheet or film. The opening polymer film is a lightweight material containing openings, holes, or perforations. The openings can be formed by embossing with a pattern (e.g., circular, rhombus, hexagonal, elliptical, triangular, rectangular, etc.) and then stretching until the openings are formed in the thinned areas created by the embossing. Such opening substrates can be formed from many polymers, such as polypropylene, polyethylene, and high-density polyethylene ("HDPE"). Opening films are used in a wide range of applications, including finger bandages, surgical gowns, drapes, masks, dental whitening strips, hydrogel scrims, nasal support materials, electrode support products, filters, food processing, packaging and textile applications, agricultural products, food packaging, and, for example, mesh for cheese production. Opening films are commercially available and sold by Schweitzer-Mauduit International, Inc. under the trademark Delnet®.

[0027] The openings formed in the first layer 20 and / or the third layer improve breathability, elasticity, and stretchability. The improved flexibility is beneficial for ensuring that the bandage 2 fits snugly to wounds that stretch, open, or contract as the user moves. Since the backing layer 6 is impermeable to fluids and other secretions from the wound, these discharges can be contained within or beneath the absorbent pad 10. The openings also impart other important properties, which will be described in more detail below. Those skilled in the art will recognize that the opening 32 may also be formed in layers other than the first and third layers of the bandage 2. For example, the opening 32 may be formed in the second layer 30, or it may penetrate the absorbent pad 10 and the backing layer 6. In some embodiments in which the bandage 2 includes multiple layers in addition to the absorbent pad 10, the size and shape of the opening 32 may differ from layer to layer. In other embodiments, the bandage 2 and the absorbent pad 10 may not have any openings 32 at all.

[0028] If it is desirable to provide the opening 32 in only one layer of the pad 10, the opening 32 can be introduced from the first layer 20 (and / or the third layer) before bonding the first layer 20 (and / or the third layer) to the second layer 30. In some embodiments, the opening 32 can be formed from both layers as a finishing step before or after bonding. In other embodiments, the opening 32 is introduced simultaneously with the bonding of the first and / or third layer of the pad to the second layer.

[0029] In some embodiments, the openings 32 may be polygonal in shape, such as hexagonal, rhombus, triangular, octagonal, square, or rectangular. In other embodiments, the openings 32 may simply be straight or curved slits penetrating the material. In yet another embodiment, the openings 32 may be irregular in shape or circular. The size of the openings may vary, but preferably not so large as to increase the overall porosity of the absorbent pad 10 excessively, as this would impair the strength of the pad 10. Furthermore, the openings 32 may vary in size and / or shape across the entire surface of the absorbent pad 10. The resulting variety of textures may, if necessary, create different wicking patterns across the entire surface of the absorbent pad 10. Those skilled in the art will recognize that the shape and size of the openings 32 are determined by determining the optimal porosity of the area across the entire absorbent pad 10, as necessary for a given application. In certain embodiments, the openings have a substantially uniform shape, enhancing the absorbency and extensibility of the absorbent article. The openings also allow water vapor and heat to escape from the wound, providing a textured surface that enhances the user's comfort of the absorbent article without giving the skin a hot, damp, plastic-like feel.

[0030] In another embodiment, the first layer 20 preferably includes a polymer mesh. In some embodiments, the polymer mesh is made from a polymer resin, preferably a thermoplastic polymer resin, which tends to give strength to the pad. In a preferred embodiment, the polymer mesh is synthesized substantially from a polyethylene article. In other embodiments, other olefin articles such as polypropylene or polyethylene-polypropylene blends may be used. In yet another embodiment, the polymer mesh further includes other materials such as polyester, rayon, cotton, or a combination thereof. The second layer 30 contains a plurality of heat-bondable fibers. In some embodiments, these fibers are binary fibers having at least two different materials. The binary fibers may be continuous (e.g., high loft) or discontinuous. The biocomponent fibers may include any suitable configuration such as core / sheath with concentric or eccentric cores, side-by-side, split pipe, sea-island type, hollow binary fibers, hollow split pipe, trefoil binary fibers, mixed fibers, striped fibers, conductive fibers, etc. The binary fibers may have a solid or hollow core. For example, split pipe or side-by-side fibers may include a hollow core.

[0031] In several embodiments, the binary fiber comprises a first polymer material and a second polymer material. The second polymer material has a lower melting temperature than the first polymer material. In one exemplary embodiment, the binary fiber comprises a core and a sheath. The sheath comprises a material having a lower melting temperature than the core material. The core may comprise any suitable material such as polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof. In one exemplary embodiment, the core comprises PET. The sheath may include any suitable material such as polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof. In one exemplary embodiment, the sheath includes PE.

[0032] In one exemplary embodiment, the fibers in the second layer are arranged to form a core in which PET is surrounded by a PE sheath. The arrangement of the PET core and PE sheath provides a composition that can be easily bonded, for example, by utilizing thermal bonding due to the difference in melting temperatures of the two components. In addition, the method of thermally bonding the first and second layers to each other does not require high-pressure mechanical force. Ultimately, these materials, their composition and processing eliminate the need for bonding techniques that break the three-dimensional structure of the composite material, allowing the article to operate with greater efficiency. In several embodiments, the mass ratio of the core to the sheath is approximately 30 / 70 to approximately 70 / 30, preferably approximately 40 / 60 to approximately 60 / 40. Within this range, the optimal overall density of the absorbent pad is maintained. Density is an important consideration for absorbent pads; if the value is too high or too low, the pad may become uncomfortable or weak and ineffective. Furthermore, if the amount of core component is excessively high, thermal bonding at the melting point of polyethylene will be insufficient, and if it is excessively low, the tensile strength of the material will be too low, making it prone to deformation and resulting in a weak product; therefore, this range is preferable. A preferred embodiment of the two-component fiber has a PET core surrounded by polyethylene, but other polyester resins may be used as the core or sheath. For example, PET can be replaced with polyethylene naphthalate, polylactic acid, etc. In some other embodiments, the configuration can be reversed so that the core contains polyethylene and is surrounded by a PET sheath. In other embodiments, polypropylene or other polymer resins may form the core of the two-component fiber. Alternatively, the core and / or sheath may be composed of fibers that are a blend of different raw materials. In some embodiments, the fibers within the second layer include a spin finish. The spin finish is selected from FDA-approved hydrophilic or hydrophobic spin finishes (for skin contact). Preferably, a hydrophilic spin finish is selected to increase liquid absorption capacity. However, it should be recognized that the spin finish may be an FDA-unapproved spin finish as long as it does not harm the skin. The spin finish content is 2% or less.

[0033] In several embodiments, the second layer further comprises at least one type of non-heat-adherent fiber. The non-heat-adherent fiber has a first melting point, and the heat-adherent fiber has a second melting point, the first melting point being at least about 15°C higher than that of the heat-adherent fiber. The non-heat-adherent fiber may include any suitable material such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or a combination thereof. For example, if HDPE is selected for the sheath, the non-adherent fiber may be PET. Heat-bondable fibers may include two-component fibers. Non-bondable fibers may have any suitable cross-section, such as circular, non-circular, 4DG, trefoil, or ribbon-shaped. Non-circular fibers have a larger specific surface area, resulting in greater liquid absorption. In several embodiments, the non-heat-adherent fibers constitute 50% by mass or less of the second layer, preferably 40% by mass or less of the second layer.

[0034] Figure 3 shows a perspective view of one embodiment of a composite fiber in a second layer 30, which includes a core-sheath configuration in which a PE sheath 15 is centrally located or surrounds a concentric PET core 12. This core-sheath arrangement is beneficial for several reasons, but is particularly beneficial in that it allows for bonding between composite fibers without the need for mechanical pressure. Thermal bonding is sufficient to create a strong adhesive force between the fibers. For example, in some embodiments, thermal bonding can be achieved by heating the material containing the polyethylene sheath 15 and the PET core 12 to a temperature above the melting point of the polyethylene sheath 15, which has a lower melting point than the PET core 12. In these embodiments, the polyethylene sheath 15 melts upon heating and fuses with one or more adjacent polyethylene sheaths, while the more rigid PET core 12 maintains a higher degree of structure than its surrounding sheaths. It is understood that this layer can be thermally bonded in other ways. For example, it is possible to melt the core fibers and sheath fibers and bond them to each other by setting the temperature above the melting points of both the core and sheath components. If the adhesion between different polymer fibers and between layers of the absorbent pad 10 is weak, the product will be prone to deformation. Calendering at very high pressures allows for very efficient fusion of fibers, but it can also cause material dissolution, potentially leading to defects that result in reduced performance during use. For example, the high mechanical stress imposed on the material by calendering parameters commonly used in this art can compress and flatten the fibers, crushing and closing the gaps, effectively causing the material to become "clogging." This significantly reduces absorbency and ultimately increases the risk of wound maceration when the final product is used.

[0035] In some embodiments, the core-sheath configuration of the polyethylene sheath 15 and PET core 12 is a central core-sheath configuration, where the PET core 12 is substantially located at the center of the polyethylene sheath 15. This embodiment is shown in Figure 3. Alternatively, these two composite fibers can be configured as an eccentric core-sheath configuration where the PET core 12 is positioned off-center (not shown). An eccentric core-sheath configuration may be desirable when a larger volume of the absorbent pad 10 is required. When the core is off-center, if the temperature is set lower than the melting point of the sheath and the core fiber, the polyethylene sheath 15 and PET core 12 will exhibit different shrinkages from each other, causing the fibers to begin curling due to the difference in shrinkage that results from the off-center position. This causes the fibers to "crinkle," and therefore, the volume within the absorbent pad 10 across the entire second layer 30 is increased. In other embodiments, the two-component fibers are designed so that, in each composite fiber, PET and polyethylene are positioned side by side in a cross-sectional view, rather than in a core-sheath configuration. Those skilled in the art will recognize that this configuration yields a highly crimpable second layer 30. Alternatively, the two-component fibers may contain multiple PET fibers within each polyethylene sheath 15. In one embodiment, a plurality of composite fibers, each comprising a polyethylene sheath 15 and a PET core 12, form a second layer 30. In this embodiment, the plurality of polyethylene sheaths 15 are non-parallel to each other. These sheaths 15 may intersect each other in either a horizontal or vertical plane. These sheaths 15 may overlap each other to form a multilayer. Each of these sheaths 15 may be limited to a single layer, or they may overlap across multiple layers. In certain embodiments, fibers are carded and then air-through bonded to produce a web. In other embodiments, fibers are spunbonded by bonding extruded spun filaments to form a web. The spunbonding method is more cost-effective than other fiber manufacturing methods and has the potential to increase manufacturing efficiency through improved throughput, reduced maintenance, space savings, increased automation, lower scrap rates, and continuous manufacturing processes (i.e., 24 / 7).

[0036] Silicone-based coatings can be applied by any preferred method, including, but not limited to, spraying a silicone-based coating agent onto fibers, immersing fibers in a container of silicone-based coating agent, applying the silicone-based coating agent to fibers in foam form, using a measuring rod or other leveling device to apply the coating agent, supplying the coating agent onto fibers using a coating head such as a slot die, or any combination of these techniques. In one exemplary embodiment, the coating is applied by spraying or immersion. The silicone-based coating comprises a silicone compound diluted with water or another suitable fluid, such that the silicone compound constitutes at least about 2% by mass of the coating, or at least about 5% by mass of the coating. In one exemplary embodiment, the silicone compound constitutes about 10% by mass of the coating. In one exemplary embodiment, the silicone compound comprises a silicone material, a surfactant, and water. The silicone and surfactant together may constitute about 5% to about 20% by mass, or about 10% to about 11% by mass, of the entire coating. In several embodiments, the silicone coating comprises a reactive silicone macroemulsion. The silicone emulsion is an insoluble silicone substantially uniformly dispersed in water with the help of a surfactant. The silicone emulsion may include, for example, dimethyl silicone emulsion, amino-type silicone emulsion, organic functional silicone emulsion, resin-type silicone emulsion, and film-forming silicone emulsion. In one exemplary embodiment, the reactive silicone macroemulsion comprises amino-modified polydimethylsiloxane and / or polyethylene glycol monotridecyl ether. In several embodiments, the amino-modified polydimethylsiloxane constitutes about 30 to about 40% by mass of the coating. In several embodiments, the polyethylene glycol monotridecyl ether constitutes about 5 to about 10% by mass of the coating. In several embodiments, the silicone coating further comprises an antistatic agent. Examples of antistatic agents include surfactants. Examples of surfactants include non-re-wetting, pyrolytic surfactants / foaming agents. In various embodiments, the added mass of the silicone coating is approximately 1.0 gsm to approximately 20 gsm, or approximately 1.5 gsm to approximately 15.5 gsm. In certain embodiments, this added mass may be approximately 2.9 gsm to approximately 10.9 gsm.

[0037] Another desirable feature of the absorbent pad 10 is its ability to separate the cellular fraction of whole blood. The applicant has found that the absorbent material has the ability to push cells from its center toward its outer edge. This is due to the unique structure of the fibers within the second layer 30. The ability to concentrate and isolate cellular components in specific spatial regions of the substrate is advantageous in clinical laboratories, for example, for the extraction or quantification of low-abundance target nucleic acids. In one exemplary embodiment, a large bandage 2 equipped with an absorbent pad 10 can be applied to a patient with necrotic wound tissue in a hospital. Considering the severity of such an infection, antibiotics can be administered to the patient as the wound heals to prevent sepsis. Because cellular components can be spatially separated from the fluid blood volume on or within the absorbent pad 10, the collection and concentration of bacterial cells from the wound is facilitated. The portion of the absorbent pad 10 containing the concentrated cells can be separated from the rest of the material, and nucleic acid extraction can be performed on only the cell-concentrated portion for sequencing and identification of pathogens. In fact, cell concentration is a significant advantage in the filter fabric industry and in clinical settings where nucleic acid extraction is performed from patient blood samples, as blood is known to contain major inhibitors of standard diagnostic techniques such as polymerase chain reaction (PCR). Conversely, if it is desirable to quantify serum biomarkers, the cell concentration zone of pad 10 can be cut off and discarded. In this case, the remaining fluid-filled portion containing the target biomarker can be used for downstream processing.

[0038] Those skilled in the art will recognize that the absorbent pad 10 may include additional materials beneficial to the bandage 2. For example, in certain embodiments, the absorbent pad 10 may include an antimicrobial agent that can be applied using a spin finish. The absorbent pad 10 may also include benzalkonium chloride (BZK). In some embodiments, the absorbent pad 10 may be supplemented with bleeding control and / or other medical powders known in the art. Hemostatic powders are commonly added to control bleeding. In some embodiments, the hemostatic powder is included in or on the absorbent pad 10 for contact with the wound. This powder may include chitosan salts, medical surfactants, and other therapeutic agents known in the art.

[0039] A method for producing an absorbent pad 10 for wound dressings is described below. This method includes the steps of providing a first polymer layer and a second layer containing at least one type of heat-adhesive fiber, and heat-bonding or laminating the first layer to the second layer. In some embodiments, the heat-adhesive fiber includes a two-component fiber having a first material or component and a second material or component as described above. The two-component fiber may be formed, for example, by selecting a heating temperature higher than the melting points of both components. In certain embodiments, the two-component fibers are formed in a core / sheath configuration as described above. The core / sheath fiber arrangement may be random or highly structured. The sheaths may be in a single-layer or multi-layer form and arranged in parallel. Layers containing core-sheath conjugate fibers utilize the difference in melting points between the core and sheath components. The difference in melting points between the two components facilitates the bonding of the fibers using thermal bonding techniques. In some embodiments, the thermal bonding process allows for the fusion of adjacent sheaths, sheaths and core components, and / or sheaths and other resins, if other resins are present. The absorbent pad can be processed to be a single layer of single-component or multi-component fibers, or a combination of two or more layers of single-component or multi-component fibers, including a layer of core-sheath fibers. By selecting an appropriate temperature, thermal bonding can occur at the intersections between sheath fibers.

[0040] In one exemplary embodiment, PET and polyethylene are configured in a core-sheath arrangement. Various types of polymers can be used for the core or sheath, but PET is preferred as the core because it gives the absorbent pad 10 elasticity and loft. In other embodiments, the method involves thermally bonding the first and second layers by selecting a heating temperature at which the PET core 12 does not substantially melt, and the polyethylene sheath 15 is a fiber that melts and is thermally bonded to the first layer. In these embodiments, thermal bonding may occur at the melting point of the polyethylene sheath 15, which has a lower melting point than the PET core 12. With this approach, thermal bonding occurs substantially only between the sheath and the first layer, and the PET core 12 is maintained to be substantially semi-rigid or rigid.

[0041] In several embodiments, the method further includes providing at least one type of non-heat-adherent fiber in the second layer or fiber layer. The non-heat-adherent fiber has a melting point at least about 15°C higher than the melting point of the heat-adherent fiber. The non-heat-adherent fiber may include a two-component fiber. The non-adherent fiber may have any preferred cross-section, such as circular, non-circular, 4DG, trefoil, or ribbon. The cross-section of a non-circular fiber has a larger specific surface area and therefore absorbs more liquid. In several embodiments, the non-heat-adherent fiber accounts for 50% by mass or less of the second layer, preferably 40% by mass or less of the second layer. In some embodiments, the method further includes spin-finishing at least some of the fibers in the second layer. The spin-finishing is preferably 2% or less.

[0042] In several embodiments, the method further comprises forming a first layer from an extruded polymer film and forming a plurality of openings in the extruded polymer film. These openings can be formed by mechanical embossing, stretching and breaking, vacuum forming, hydroforming, hydrocutting, needle punching, ultrasonic cutting, slitting, ring rolling, and any combination thereof. Ultrasonic cutting is preferred because it allows for high-precision shaping of the openings, but any method known in the art can be used. The process of forming openings is important for enhancing the absorbency and extensibility of the absorbent article. The openings allow water vapor and heat to escape from the wound, providing a comfortable, cooled, textured surface for the user. This process can be performed separately for each layer of the pad, or for a single layer. If it is desirable to provide openings only for a single layer of the pad, the opening-forming process can be performed for the first layer, before the first and second layers are bonded together. In some embodiments, the method includes forming openings from both layers, for example, as a finishing step after the heat bonding process of these two layers. In yet other embodiments, the method includes forming openings simultaneously with the bonding of these two layers. The absorbent pad of the bandage is a thin, absorbent two-layer structure processed without the use of high-pressure calendering, thereby substantially maintaining the material's three-dimensional structure and porosity. The individual shapes of these openings and their uniformity throughout the entire pad layer of the bandage are precisely and well maintained by the pad's fiber and two-layer structure, high-precision cutting using ultrasound, and the absence of calendering pressure during manufacturing.

[0043] In several embodiments, the method further includes thermally bonding a third layer to a second layer such that the second layer is positioned between the first and third layers. Similar to the first layer described above, openings may be formed within the third layer. The openings may be formed simultaneously in the first and third layers, or in separate steps. In certain embodiments, the method may include a second bonding step. In preferred embodiments, the method includes bonding the two layers using ultrasonic bonding. Alternatively, if thermal bonding is used instead of ultrasonic bonding in this step, the melting point temperature of polyethylene or a polyethylene blend can be applied. This allows the molten sheath in the second layer 30 to fuse with the polymer of the first layer it contacts. The unique configuration disclosed herein avoids not only pore crushing and reducing the structural integrity of the absorbent pad, but also manufacturing processes that are widely practiced in the art. This pad manufacturing method does not require high-pressure calendering, yet high affinity bonding of the fibers and layers within the pad is still achieved. [Examples]

[0044] Example 1 The applicant tested the water absorption of the absorbent pad described herein. The absorbent pad was manufactured as described above. 1.5-5 denier HDPE / PET bicomponent fibers were carded and then air-through or heat-bonded. These nonwoven fabrics were then laminated onto an extruded opening film under minimal pressure. The pad was cut into 7.62 cm (3 inch) x 10.16 cm (4 inch) samples and placed in a cylindrical wire basket with a height of 10.16 cm (4 inch), a radius of 2.54 cm (1 inch), and weighing approximately 7.5 grams. The container was filled with water to a depth that submerged the entire basket. The samples were placed in the basket so that the length of 10.16 cm (4 inch) was stretched longitudinally (MD). For weighing, the wire basket was placed on a plastic tray. The sample was weighed to the nearest 0.01 gram (WS). The tare mass of the plastic tray (WG) and the test basket (WB) was also weighed to the nearest 0.01 gram. Next, the sample was placed in the basket so that the 7.62 cm (3 inch) edge was parallel to the side of the basket. Holding the basket so that the sample was closest to the water, it was dropped sideways into the container of water from a height of 2.54 cm (1 inch). The basket was left submerged in the water for 10 seconds. After that, the basket and sample were removed from the water and drained for 1 minute. After draining, the basket and sample (Wt) were placed in a plastic dish and weighed to the nearest 0.01 gram. Next, the water absorption capacity of the sample was calculated in oz / sy based on the formula C = [Wt - (WB + WS + WG)] × 3.82 (wherein C = volume (oz / yd² units), Wt = total mass of the basket, plastic dish, sample and water after immersion (in grams), WB = mass of the basket (in grams), WG = mass of the plastic dish (in grams), WS = mass of the sample before immersion in a dry state (in grams). 3.82 is a conversion factor).

[0045] The applicant tested three different sample absorption pads as described above, and calculated the average value of these three test samples (left, right, and center) as the liquid absorption capacity. Next, this capacity, expressed in oz / yd² units, was converted to g / g (i.e., net moisture increase mass (g) / initial material mass (g)) of the sample. After conducting multiple such tests, it was confirmed that the liquid absorption capacity of the sample was in the range of approximately 10 g / g to approximately 20 g / g.

[0046] Example 2 The applicant tested the water absorption of the absorbent pad described herein. 1.5-5 denier HDPE / PET bicomponent continuous fibers were spunbonded and then coated with a silicon-based coating as described above, followed by drying at 115.556°C (240°F) for 3 minutes. This silicone-based coating contained 10% by mass of reactive silicone macroemulsion, 1% by mass of non-re-wetting pyrolytic surfactant / foaming agent, and 89% by mass of water. The bicomponent fibers had an eccentric sheath / core structure. Samples were cut to a size of 7.62 cm (3 inches) × 10.16 cm (4 inches), laminated onto an open film, and then the water absorption value was calculated.

[0047] The applicant tested two samples of spunbond HDPE / PET bicomponent fiber without silicone coating (labeled "uncoated spunbond") and two samples of coated spunbond HDPE / PET bicomponent fiber (labeled "coated spunbond"). Furthermore, the applicant tested two samples of spunbond HDPE / PET bicomponent fiber that were carded and then air-through bonded (labeled "carded") as described in Example 1. The carded samples were not coated with silicone. The water absorption test was performed according to the same criteria as described in Example 1. The results of this test are shown in Table 1 below. [Table 1]

[0048] As shown in Table 1, the silicone coating significantly improved the water absorption of the spunbond fibers (i.e., approximately 2.6 g / g to 5.7 g / g for uncoated samples, compared to approximately 11.2 or 11.3 g / g for coated samples). Carded samples showed higher water absorption than both coated and uncoated spunbond samples. Carded samples also had a higher basis weight (approximately 86 or 87 g / m2).

[0049] Furthermore, the applicant tested two samples of point-bonded spunbond single-component PET fibers. The water absorption test was performed according to the same criteria as described above in Example 1. The first sample was uncoated, while the second sample was coated with the silicon-based coating described above. The results of this test are shown in the table below. [Table 2]

[0050] As shown, silicone-based coatings improved the water absorption of single-component fibers. However, the overall water absorption of both coated and uncoated samples was significantly lower than that of the biocomponent carded samples and coated spunbond samples shown in Table 1. Therefore, the two-component composition described herein significantly improves the water absorption of fibers.

[0051] Other embodiments will become apparent to those skilled in the art by considering the description and practice of the embodiments disclosed herein. The description and examples should be considered illustrative only, and the true scope and spirit of the embodiments shall be shown by the following claims.

[0052] For example, in a first embodiment, the first embodiment is an absorbent pad for a wound dressing, comprising a first layer containing a polymer and a second layer heat-bonded to the first layer and containing at least one type of heat-bondable fiber. The second embodiment is the first embodiment, wherein the first layer includes a polymer film. A third embodiment is any combination of the first two embodiments, wherein the first layer includes an extruded film having openings. A fourth embodiment is any combination of the first three embodiments, wherein the opening includes a hole or a perforation. The fifth embodiment is any combination of the first four embodiments, wherein the opening is hexagonal, square, rhombus, circular, elliptical, triangular, rectangular, or a combination thereof.

[0053] The sixth embodiment is any combination of the first five embodiments, wherein the first layer includes an open film, a perforated film, a microporous film, a mesh, a polymer mesh, a knitted material, or a combination thereof. The seventh embodiment is any combination of the first six embodiments, further comprising a third layer containing a polymer. The eighth embodiment is any combination of the first seven embodiments, wherein the second layer is positioned between the first and third layers. The ninth embodiment is any combination of the first eight embodiments, wherein the third layer includes a polymer film. The tenth embodiment is any combination of the first nine embodiments, wherein the third layer includes an extruded opening film.

[0054] The eleventh embodiment is any combination of the first ten embodiments, wherein the heat-bondable fibers include two-component fibers. The twelfth embodiment is any combination of the first eleven embodiments, wherein the biocomponent fiber includes a core and a sheath. The thirteenth embodiment is any combination of the first twelve embodiments, wherein the core comprises a first material and the sheath comprises a second material, the second material having a lower melting temperature than the first material. The 14th embodiment is any combination of the first 13 embodiments, wherein the core is made of a material selected from the group consisting of polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

[0055] The 15th embodiment is any combination of the first 14 embodiments, wherein the sheath comprises a material selected from the group consisting of polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof. The sixteenth embodiment is any combination of the first fifteen embodiments, wherein the mass ratio of the core to the sheath is approximately 30 / 70 to approximately 70 / 30. The 17th embodiment is any combination of the first 16 embodiments, with a ratio of approximately 40 / 60 to approximately 60 / 40. The 18th embodiment is any combination of the first 17 embodiments, wherein the two-component fiber is selected from the group consisting of side-by-side, split pie, sea-island type, hollow two-component fiber, hollow split pie, three-lobe two-component fiber, mixed fiber, stripe fiber, conductive fiber, and combinations thereof. The 19th embodiment is any combination of the first 18 embodiments, wherein the two-component fiber comprises a first polymer material and a second polymer material, the second polymer material having a lower melting temperature than the first polymer material. The 20th embodiment is any combination of the first 19 embodiments, wherein the mass ratio of the first polymer material to the second polymer material is approximately 20 / 80 to approximately 80 / 20.

[0056] The 21st embodiment is any combination of the first 20 embodiments, wherein the second layer comprises at least one type of non-thermoplastic fiber. The 22nd embodiment is any combination of the first 21 embodiments, wherein the non-heat-bondable fibers include two-component fibers. The 23rd embodiment is any combination of the first three embodiments, wherein the non-heat-bondable fibers have a first melting point and the heat-bondable fibers have a second melting point, the first melting point being at least about 15°C higher than that of the heat-bondable fibers. The 24th embodiment is any combination of the first 23 embodiments, wherein the non-heat-bondable fibers include a material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or a combination thereof. The 25th embodiment is any combination of the first 24 embodiments, wherein non-thermoplastic fibers account for 50% by mass or less of the second layer.

[0057] The 26th embodiment is any combination of the first 25 embodiments, wherein non-thermoplastic fibers account for 40% by mass or less of the second layer. The 27th embodiment is any combination of the first 26 embodiments, wherein the absorbent pad has a thickness ranging from approximately 40 mils to approximately 200 mils. The 28th embodiment is any combination of the first 27 embodiments, wherein the absorbent pad has a liquid absorption capacity of approximately 5 g / g to approximately 100 g / g. The 29th embodiment is any combination of the first 28 embodiments, wherein the absorbent pad has a liquid absorption capacity of approximately 10 g / g to approximately 20 g / g. The 30th embodiment is any combination of the first 29 embodiments, wherein the heat-bondable fibers are formed from carding and have a liquid absorption capacity of at least about 14 g / g.

[0058] The 31st embodiment is any combination of the first 30 embodiments, wherein heat-bondable fibers are spunbonded. The 32nd embodiment is any combination of the first 31 embodiments, wherein heat-bondable fibers are coated with a silicone compound. The 33rd embodiment is any combination of the first 32 embodiments, wherein the silicone compound is about 1.5 to about 15% by mass of the total mass of the second layer. The 34th embodiment is any combination of the first 33 embodiments, wherein the heat-bondable fibers have a liquid absorption capacity of at least about 10 g / g. The 35th embodiment is any combination of the first 34 embodiments, wherein the second layer has a basis weight of approximately 60 gsm to approximately 75 gsm. The 36th embodiment is any combination of the first 35 embodiments, wherein the silicone coating comprises a reactive silicone macroemulsion.

[0059] In another embodiment, a bandage is provided that includes absorbent pads in any combination of the first 36 embodiments. In another embodiment, a wound dressing is provided that includes absorbent pads in any combination of the first 36 embodiments. In another embodiment, the first embodiment is a bandage comprising an adhesive layer and an absorbent pad bonded to the adhesive layer and extending over at least a portion of the adhesive layer. The absorbent pad comprises a first polymer layer and a second layer heat-bonded to the first layer and comprising at least one type of heat-bondable fiber. The second embodiment is the first embodiment, wherein the first layer comprises an extruded polymer film having openings. A third embodiment is any combination of the first two embodiments, further comprising a third layer including an extruded polymer opening film, wherein the second layer is positioned between the first and third layers. A fourth embodiment is any combination of the first three embodiments, wherein the heat-bondable fibers include biocomponent fibers. The fifth embodiment is any combination of the first four embodiments, wherein the biocomponent fiber includes a core and a sheath.

[0060] The sixth embodiment is any combination of the first five embodiments, wherein the core comprises a first material and the sheath comprises a second material, the second material having a lower melting temperature than the first material. The seventh embodiment is any combination of the first six embodiments, wherein the core comprises a material selected from the group consisting of polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof. The eighth embodiment is any combination of the first seven embodiments, wherein the sheath comprises a material selected from the group consisting of polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof. The ninth embodiment is any combination of the first eight embodiments, wherein the mass ratio of the core to the sheath is approximately 30 / 70 to approximately 70 / 30. The tenth embodiment is any combination of the first nine embodiments, wherein the two-component fiber is selected from the group consisting of side-by-side, split pie, sea-island type, hollow two-component fiber, hollow split pie, three-lobe two-component fiber, mixed fiber, sliver fiber, conductive fiber, and combinations thereof.

[0061] The eleventh embodiment is any combination of the first ten embodiments, wherein the second layer comprises at least one non-heat-adhesive fiber having a first melting point, and the heat-adhesive fiber has a second melting point, the first melting point of which is at least about 15°C higher than that of the heat-adhesive fiber. The twelfth embodiment is any combination of the first eleven embodiments, wherein the non-heat-bondable fibers include a material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or a combination thereof. The 13th embodiment is any combination of the first 12 embodiments, wherein the absorbent pad has a thickness ranging from approximately 40 mils to approximately 200 mils. The 14th embodiment is any combination of the first 13 embodiments, wherein the absorbent pad has an absorbency of approximately 5 g / g to approximately 100 g / g. The 15th embodiment is any combination of the first 14 embodiments, wherein the second layer has a liquid absorption capacity of approximately 10 g / g to approximately 20 g / g.

[0062] The sixteenth embodiment is any combination of the first fifteen embodiments, wherein the heat-bondable fibers are formed from carding and have a liquid absorption capacity of at least about 14 g / g. The 17th embodiment is any combination of the first 16 embodiments, wherein heat-bondable fibers are spunbonded. The 18th embodiment is any combination of the first 17 embodiments, wherein heat-bondable fibers are coated with a silicone-based coating containing a silicone compound. The 19th embodiment is any combination of the first 18 embodiments, wherein the heat-bondable fibers have a liquid absorption capacity of at least about 10 g / g.

[0063] In another embodiment, the first embodiment is a method for manufacturing a wound dressing or an absorbent pad for a dressing. The method includes providing a first polymer layer and a second layer comprising at least one type of heat-bondable fiber, and heat-bonding the first layer and the second layer. A second embodiment is the first embodiment, further comprising forming a plurality of openings in the first layer. The third embodiment is any combination of the first two embodiments, wherein the multiple openings are formed by mechanical embossing, stretching and breaking, vacuum forming, hydroforming, hydrocutting, needle punching, ultrasonic, slitting, ring rolling, and any combination thereof. A fourth embodiment is any combination of the first three embodiments, further comprising forming a first layer from an extruded polymer film and forming a plurality of openings in the extruded polymer film. A fifth embodiment is any combination of the first four embodiments, further comprising heat-bonding a second layer to a third layer comprising an extruded polymer opening film, wherein the second layer is positioned between the first and third layers.

[0064] The sixth embodiment is any combination of the first five embodiments, wherein the heat-bondable fibers include biocomponent fibers, and the method further comprises forming a sheath around one or more core fibers. The seventh embodiment is any combination of the first six embodiments, wherein the core fiber is made of a material selected from the group consisting of polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof. The eighth embodiment is any combination of the first seven embodiments, wherein the sheath comprises a material selected from the group consisting of polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof. The ninth embodiment further comprises providing at least one non-heat-adherent fiber in the second layer, the non-heat-adherent fiber having a first melting point and the heat-adherent fiber having a second melting point, the first melting point being at least about 15°C higher than that of the heat-adherent fiber, any combination of the first eight embodiments. The tenth embodiment is any combination of the first nine embodiments, wherein the non-heat-bondable fibers include a material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

[0065] An eleventh embodiment is any combination of the first ten embodiments, further comprising forming a second layer by carding a plurality of heat-bondable fibers. A twelfth embodiment is any combination of the first eleven embodiments, further comprising forming a second layer by a spunbond of multiple heat-bondable fibers. A thirteenth embodiment is any combination of the first twelve embodiments, further comprising coating a plurality of heat-bondable fibers with a silicon compound. In another embodiment, an absorbent pad is provided which is manufactured from any combination of steps of the 13 embodiments described above. In another embodiment, a bandage is provided which is manufactured from any combination of steps of the 13 embodiments described above.

Claims

1. A first layer containing a polymer, A second layer, which is heat-bonded to the first layer and contains at least one type of heat-bondable fiber, Includes absorbent pads for wound dressings.

2. The absorbent pad according to claim 1, wherein the first layer comprises a polymer film.

3. The absorbent pad according to claim 2, wherein the first layer comprises an extruded film having an opening.

4. The absorbent pad according to claim 3, wherein the opening includes a hole or perforation.

5. The absorbent pad according to claim 3, wherein the opening is hexagonal, square, rhombus, circular, elliptical, triangular, rectangular, or a combination thereof.

6. The absorbent pad according to claim 1, wherein the first layer comprises an open film, a perforated film, a microporous film, a mesh, a polymer mesh, a knitted material, or a combination thereof.

7. The absorbent pad according to claim 1, further comprising a third layer containing a polymer.

8. The absorbent pad according to claim 7, wherein the second layer is disposed between the first layer and the third layer.

9. The absorbent pad according to claim 7, wherein the third layer includes a polymer film.

10. The absorbent pad according to claim 7, wherein the third layer includes an extruded opening film.

11. The absorbent pad according to claim 1, wherein the heat-bondable fibers include two-component fibers.

12. The absorbent pad according to claim 11, wherein the biocomponent fiber includes a core and a sheath.

13. The absorbent pad according to claim 12, wherein the core comprises a first material, and the sheath comprises a second material, the second material having a lower melting temperature than the first material.

14. The absorbent pad according to claim 12, wherein the core comprises a material selected from the group consisting of polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

15. The absorbent pad according to claim 12, wherein the sheath comprises a material selected from the group consisting of polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof.

16. The absorbent pad according to claim 12, wherein the mass ratio of the core to the sheath is approximately 30 / 70 to approximately 70 / 30.

17. The absorbent pad according to claim 16, wherein the ratio is approximately 40 / 60 to approximately 60 / 40.

18. The absorbent pad according to claim 11, wherein the two-component fibers are selected from the group consisting of side-by-side, split pie, sea-island type, hollow two-component fibers, hollow split pie, three-lobe two-component fibers, mixed fibers, striped fibers, conductive fibers, and combinations thereof.

19. The absorbent pad according to claim 18, wherein the two-component fiber comprises a first polymer material and a second polymer material, and the second polymer material has a lower melting temperature than the first polymer material.

20. The absorbent pad according to claim 19, wherein the mass ratio of the first polymer material to the second polymer material is about 20 / 80 to about 80 / 20.

21. The absorbent pad according to claim 1, wherein the second layer comprises at least one type of non-heat-adherent fiber.

22. The absorbent pad according to claim 21, wherein the heat-bondable fibers include two-component fibers.

23. The absorbent pad according to claim 21, wherein the non-heat-adherent fiber has a first melting point, and the heat-adherent fiber has a second melting point, the first melting point being at least about 15°C higher than that of the heat-adherent fiber.

24. The absorbent pad according to claim 23, wherein the non-heat-adherent fibers include a material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

25. The absorbent pad according to claim 23, wherein the heat-bondable fibers account for 50% by mass or less of the second layer.

26. The absorbent pad according to claim 23, wherein the non-heat-adherent fibers account for 40% by mass or less of the second layer.

27. The absorbent pad according to claim 1, having a thickness in the range of approximately 40 mils to approximately 200 mils.

28. The absorbent pad according to claim 1, having a liquid absorption capacity of approximately 5 g / g to approximately 100 g / g.

29. The absorbent pad according to claim 1, having a liquid absorption capacity of approximately 10 g / g to approximately 20 g / g.

30. The absorbent pad according to claim 1, wherein the heat-bondable fibers are formed from carding and have a liquid absorption capacity of at least about 14 g / g.

31. The absorbent pad according to claim 1, wherein the heat-bondable fibers are spunbonded.

32. The absorbent pad according to claim 31, wherein the heat-bondable fibers are coated with a silicone compound.

33. The absorbent pad according to claim 32, wherein the silicone compound is about 1.5 to about 15% by mass of the total mass of the second layer.

34. The absorbent pad according to claim 32, wherein the heat-bondable fibers have a liquid absorption capacity of at least about 10 g / g.

35. The absorbent pad according to claim 31, wherein the second layer has a basis weight of about 60 gsm to about 75 gsm.

36. The absorbent pad according to claim 31, wherein the silicone-based coating comprises a reactive silicone macroemulsion.

37. A bandage comprising the absorbent pad described in claim 1.

38. A wound bandage comprising the absorbent pad described in claim 1.

39. Adhesive layer; and An absorbent pad bonded to the adhesive layer and extending to at least a portion of the adhesive layer, comprising a first polymer layer and a second layer heat-bonded to the first layer and containing at least one type of heat-bondable fiber, Bandages, including

40. The bandage according to claim 39, wherein the first layer comprises an extruded polymer film having an opening.

41. The bandage according to claim 39, further comprising a third layer containing an extruded polymer opening film, wherein the second layer is disposed between the first layer and the third layer.

42. The bandage according to claim 39, wherein the heat-adhesive fibers include biocomponent fibers.

43. The bandage according to claim 42, wherein the biocomponent fiber includes a core and a sheath.

44. The bandage according to claim 43, wherein the core comprises a first material, and the sheath comprises a second material, the second material having a lower melting temperature than the first material.

45. The bandage according to claim 43, wherein the core comprises a material selected from the group consisting of polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

46. The bandage according to claim 43, wherein the sheath comprises a material selected from the group consisting of polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof.

47. The bandage according to claim 43, wherein the mass ratio of the core to the sheath is approximately 30 / 70 to approximately 70 / 30.

48. The bandage according to claim 42, wherein the two-component fibers are selected from the group consisting of side-by-side, split pie, sea-island type, hollow two-component fibers, hollow split pie, three-lobe two-component fibers, mixed fibers, striped fibers, conductive fibers, and combinations thereof.

49. The bandage according to claim 39, wherein the second layer comprises at least one non-heat-adhesive fiber having a first melting point, and the heat-adhesive fiber has a second melting point, the first melting point being at least about 15°C higher than that of the heat-adhesive fiber.

50. The bandage according to claim 49, wherein the non-heat-adhesive fibers include a material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

51. The bandage according to claim 39, wherein the absorbent pad has a thickness in the range of about 40 mils to about 200 mils.

52. The bandage according to claim 39, wherein the absorbent pad has an absorbency of approximately 5 g / g to approximately 100 g / g.

53. The bandage according to claim 39, wherein the second layer has a liquid absorption capacity of about 10 g / g to about 20 g / g.

54. The bandage according to claim 39, wherein the heat-adhesive fibers are formed from carding and have a liquid absorption capacity of at least about 14 g / g.

55. The bandage according to claim 39, wherein the heat-bondable fibers are spunbonded.

56. The bandage according to claim 55, wherein the heat-adhesive fibers are coated with a silicone-based coating containing a silicone compound.

57. The bandage according to claim 55, wherein the heat-adhesive fibers have a liquid absorption capacity of at least about 10 g / g.

58. A method for making an absorbent pad for wound dressings, To provide a first polymer layer and a second layer comprising at least one type of heat-bondable fiber; and The first layer and the second layer are heat-bonded together. Methods that include...

59. The method according to claim 56, further comprising forming a plurality of openings in the first layer.

60. The method according to claim 57, wherein the plurality of openings are formed by mechanical embossing, stretch fracture, vacuum forming, hydroforming, hydrocutting, needle punching, ultrasonic, slitting, ring rolling, and any combination thereof.

61. The method according to claim 58, further comprising forming the first layer from an extruded polymer film and forming a plurality of openings in the extruded polymer film.

62. The method according to claim 59, further comprising heat-bonding the second layer to a third layer comprising an extruded polymer opening film, wherein the second layer is positioned between the first layer and the third layer.

63. The method according to claim 56, further comprising the heat-bondable fibers including biocomponent fibers and forming a sheath around one or more core fibers.

64. The method according to claim 61, wherein the core fiber comprises a material selected from the group consisting of polyethylene terephthalate (PET), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

65. The method according to claim 61, wherein the sheath comprises a material selected from the group consisting of polyethylene (PE), high-density polyethylene (HDPE), low-melting-point polyethylene terephthalate (CoPET), low-melting-point polylactic acid (PLA), polypropylene (PP), and combinations thereof.

66. The method according to claim 56, further comprising providing at least one non-heat-adherent fiber in the second layer, wherein the non-heat-adherent fiber has a first melting point, and the heat-adherent fiber has a second melting point, the first melting point being at least about 15°C higher than that of the heat-adherent fiber.

67. The method according to claim 64, wherein the non-heat-adherent fibers include a material selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polylactic acid (PLA), polypropylene (PP), or a combination thereof.

68. The method according to claim 56, further comprising forming the second layer by carding a plurality of heat-adhesive fibers.

69. The method according to claim 56, further comprising forming the second layer with a spunbond of multiple heat-bondable fibers.

70. The method according to claim 67, further comprising coating the plurality of heat-adhesive fibers with a silicon compound.

71. An absorbent pad manufactured by the process described in claim 56.

72. A bandage manufactured by the process described in claim 56.

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