Patent Application
20200085349
The disclosed and described technology relates generally to single layer and multilayer adhesive systems that can be used to attach, for example, medical devices to skin or can be used, for example, to apply bandages to skin.
Current adhesive systems have difficulty remaining on the skin for extended periods of time because they do not address the differences in mechanical properties between the skin and the adhesive, i.e., stress/strain differentials that exist between skin and the adhesive systems. Skin typically has a low stress strain relationship that may be approximated as 0.05 MPa for strains of 1.0 or 0.02 MPa for strains of 0.4. The skin is viscoelastic and current adhesive systems are typically highly elastic. Because of the mechanical mismatch between the skin and current adhesive systems, when current adhesive systems are in place on skin and the skin moves (stretches/tension and compresses/compression), these adhesive systems do not move to the same extent as the skin and therefore, experience stress/strain mismatch between the adhesive system material and the skin. This mismatch results in high shear forces at the interface between the adhesive system adhesive layer and the skin upon which it is adhered. As a result of these shear forces, current adhesive systems experience edge peel, which eventually leads to peel off of the entire adhesive system.
Another issue with current adhesive systems is that they suffer from moisture loading (moisture trapped between the skin and the adhesive system) because they have an inadequate moisture vapor transmission rate (“MVTR”), which results in “float off” of the system. MVTR is a measure of the passage of water vapor through a substance and/or barrier. Because perspiration naturally occurs on the skin, if the MVTR of a material or adhesive system is low, this can result in moisture accumulation between the skin and the adhesive system that can promote bacterial growth, cause skin irritation, and can cause the adhesive system to peel away or “float off” from the skin.
Thus, adhesive systems must be designed to (1) address the mismatch of mechanical properties that exist between skin and the adhesive systems and (2) have a high MVTR. Prior adhesive systems have attempted to address the issue of mismatch of mechanical properties and the resulting edge peel, by using aggressive adhesives, i.e., adhesives that have high adhesion to skin. An adhesive's aggressiveness is defined by its initial bond strength and its sustained bond strength. However, these aggressive adhesives do not address the main problem of strain mismatch and the high shear forces that result between the skin and the adhesive and therefore, result in systems that do not expand and contract to the same extent as the skin and remain strongly attached to the skin resulting in very high shear forces leading to pain to the wearer, and which will eventually lead to edge peel and peel off. Additionally, using an aggressive adhesive is very difficult and painful to remove from the skin when a wearer desires to remove the adhesive system. However, an adhesive that is not sufficiently aggressive, will not maintain attachment to the skin as the skin expands and contracts and will result in edge peel and peel off.
Accordingly, adhesive system embodiments of the present invention have been designed to address these deficiencies of prior adhesive systems.
Methods and apparatuses or devices being disclosed herein each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure, for example, as expressed by the claims which follow, its more prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description,” one will understand how the features being disclosed and described provide advantages that include monitoring, diagnosing, and treating a patient using results obtained from an analyte sensor.
Systems are disclosed for an adhesive system for attaching an optical sensor-transmitter system. In one example, the adhesive system is for adhering a medical device to the skin of a patient. The adhesive system can include an outside layer, wherein the outside layer is elastic and re-sealable to the skin of the patient. The outside layer can be configured to form a ring. The adhesive system can include an inside layer, wherein the inside layer is composed of a material with a high moisture vapor transmission rate. The inside layer can be joined with the outside layer such that a small gap is formed between the inside layer and the outside layer.
Disclosed is an adhesive system for adhering a medical device to the skin of a patient. In some examples, the adhesive system can include an outside layer and an inside layer. In some embodiments, the outside layer is elastic and re-sealable to the skin of the patient. In other embodiments, the outside layer is configured to form a ring. In some embodiments, the inside layer is composed of a material with a high moisture vapor transmission rate. In other embodiments, the inside layer can be joined with the outside layer such that a small gap is formed between the inside layer and the outside layer.
Additional embodiments of the adhesive system are directed to multilayer adhesive systems. In some embodiments, the multilayer adhesive system comprises a first layer that includes a first layer adhesive for attaching to skin. The first layer: (i) has a first area defined by a first perimeter, (ii) has a first layer effective elastic modulus that is maintained for a first strain, and (iii) comprises a material having a first layer inherent elastic modulus that is higher than the first layer effective elastic modulus. The adhesive system also includes a second layer that is attached to the first layer. The second layer: (i) has a second area defined by a second perimeter, where portions of the second area extend beyond the first perimeter, (ii) provides mechanical reinforcement to the first layer, (iii) has a second layer effective elastic modulus that is maintained for a second strain, and (iv) comprises a material having a second layer inherent elastic modulus that is higher than the second layer effective elastic modulus. In some embodiments, the multilayer adhesive system has an effective system elastic modulus that is maintained for a third strain.
Multilayer adhesive system embodiments disclosed herein can comprise a first layer that includes a first layer adhesive for attaching to skin, where the first layer: (i) has a first area defined by a first perimeter and (ii) comprises a material having a first layer inherent elastic modulus. The system also includes a second layer attached to the first layer, where the second layer: (i) has a second area defined by a second perimeter, wherein portions of the second area extend beyond the first perimeter, (ii) provides mechanical reinforcement to the first layer, (iii) has a second layer effective elastic modulus that is maintained for a second strain, and (iv) comprises a material having an second layer inherent elastic modulus that is higher than the second layer effective elastic modulus. In some embodiments, the multilayer adhesive system has an effective system elastic modulus that is maintained for a third strain.
Certain embodiments are directed to adhesive systems that include a first layer that comprises a first material that has a first inherent elastic modulus, a plurality of first layer perforations that form a plurality of discontinuous portions in the first layer, a first area defined by a first perimeter, an adhesive for attaching to skin, and a first effective elastic modulus that is lower than the first inherent elastic modulus. The adhesive system also includes a second layer that comprises a second material that has a second inherent elastic modulus, a plurality of second layer perforations, a second area defined by a second perimeter, an adhesive for attaching to the first layer, and a second effective elastic modulus that is lower than the second inherent elastic modulus.
The adhesive systems disclosed herein also include embodiments directed composite adhesive system that comprise a first layer for attaching to skin, where the first layer has (i) a first area defined by a first perimeter and (ii) a first layer inherent elastic modulus that is maintained for a first strain. The system also includes a second layer that is attached to the first layer, where the second layer (i) has a second area substantially equal to the first area and a second perimeter substantially equal to the first perimeter, (ii) provides mechanical reinforcement to the first layer, (iii) has a second layer effective elastic modulus that is maintained for a second strain, and (iv) comprises a material having a second layer inherent elastic modulus that is higher than the second layer effective elastic modulus. Lastly, the system includes a third layer that is attached to the second layer with a third layer adhesive. The third layer: (i) has a third area defined by a third perimeter, (ii) provides mechanical reinforcement to the second layer, (iii) has a third layer effective elastic modulus that is maintained for a third strain, and (iv) comprises a material having a third layer inherent elastic modulus that is higher than the third layer effective elastic modulus. In some embodiments, the composite adhesive system has an adhesive system effective elastic modulus that is maintained for a fourth strain.
Additional embodiments of a three-layer adhesive system include a first layer that has a first layer adhesive for attaching to skin, where the first layer: (i) has a first area defined by a first perimeter, (ii) has a first layer effective elastic modulus that is maintained for a first strain, and (iii) comprises a material having a first layer inherent elastic modulus that is higher than the first layer effective elastic modulus. The second layer, which is attached to the first layer, (i) has a second area substantially equal to the first area and a second perimeter substantially equal to the first perimeter, (ii) provides mechanical reinforcement to the first layer, (iii) has a second layer effective elastic modulus that is maintained for a second strain, and (iv) comprises a material having a second layer inherent elastic modulus that is higher than the second layer effective elastic modulus. The third layer is attached to the second layer with a third layer adhesive. The third layer: (i) has a third area defined by a third perimeter, (ii) provides mechanical reinforcement to the second layer, (iii) has a third layer effective elastic modulus that is maintained for a third strain, and (iv) comprises a material having a third layer inherent elastic modulus that is higher than the third layer effective elastic modulus. In some embodiments, the multilayer adhesive system has an adhesive system effective elastic modulus that is maintained for a fourth strain.
Embodiments are also directed to a method of wearing an adhesive system where the method comprises the steps of providing an adhesive system that includes a first layer made a first material with a first inherent elastic modulus and having, a plurality of first layer perforations that form a plurality of discontinuous portions in the first layer, a first area defined by a first perimeter, an adhesive for attaching to skin, and a first effective elastic modulus that is lower than the first inherent elastic modulus. The system also includes a second layer made of a second material having a second inherent elastic modulus and having a plurality of second layer perforations, a second area defined by a second perimeter, an adhesive for attaching to the first layer, and a second effective elastic modulus that is lower than the second inherent elastic modulus. The method includes applying the adhesive system to skin, applying a tensile force to the adhesive system to achieve a strain of up to 0.4, causing at least one discontinuous portion in the first layer to separate from an adjacent discontinuous portion in the first layer, forming concentrated areas of stress between adjacent second layer perforations, causing the second layer to plastically deform under the applied tensile force, and removing the tensile force.
Further embodiments of the invention are directed to an adhesive system, having a first layer including a first layer material with a top and a bottom having a bottom perimeter, and a first layer adhesive on the bottom for attaching to skin, the first layer having an inherent modulus of elasticity. The adhesive system also includes a second adhesive that is more aggressive than the first layer adhesive, the second adhesive along only the bottom perimeter. The first layer includes a plurality of modifications therein that result in the first layer having an effective modulus of elasticity that is lower than the inherent modulus of elasticity of the first layer. In some embodiments, the plurality of modifications in the first layer are a plurality of perforations.
Additional embodiments of the invention are directed to an adhesive system that includes a circular spun lace non-woven material that comprises a top and a bottom having a bottom perimeter, and an adhesive on the bottom for attaching to skin where the spun lace non-woven material has an inherent modulus of elasticity. The adhesive system also includes a hydrocolloid material ring around only the bottom perimeter of the spun lace non-woven material. In this embodiment, the spun lace non-woven material includes a plurality of rings having a plurality of perforations that transform the adhesive system into an adhesive system having an effective modulus of elasticity that is lower than the inherent modulus of elasticity of the spun lace non-woven material.
In some embodiments, the invention is directed to an adhesive system having at least one layer comprising a material having a top and a bottom including a bottom perimeter, a first adhesive on the bottom for at least partially attaching to skin, a first inherent modulus of elasticity, and a plurality of modifications therein that result in the first layer having an effective modulus of elasticity that is lower than the first inherent modulus of elasticity. In these embodiments, the adhesive system also includes a second adhesive that is more aggressive than the first adhesive, the second adhesive disposed along only the bottom perimeter.
Furthermore, embodiments of the invention are directed to an adhesive system that includes a top layer having a top layer material and a top layer adhesive, a bottom layer having a bottom layer material with a first side and a second side and a bottom layer adhesive on the second side, a plurality of layers between the top layer and the bottom layer, each of the plurality of layers having a layer material and a layer adhesive, and an aggressive adhesive that is more aggressive than the bottom layer adhesive, the aggressive adhesive disposed upon only a portion of the second side of the bottom layer, the aggressive adhesive for attaching to skin. In these embodiments, at least one of the top layer, the bottom layer and the plurality of layers includes a plurality of modifications therein that result in said layer having an effective modulus of elasticity that is lower than the inherent modulus of elasticity of said layer. In some embodiments, the plurality of modifications are a plurality of perforations.
In some embodiments the invention is directed to a medical device that comprises an analyte sensor and an adhesive system. Embodiments of the adhesive comprise a first layer including a first layer material having a top and a bottom having a bottom perimeter and a first layer adhesive on the bottom for attaching to skin where the first layer has an inherent modulus of elasticity, and a second adhesive that is more aggressive than the first layer adhesive where the second adhesive is included along only the bottom perimeter. In some embodiments, the first layer includes a plurality of modifications therein that result in the first layer having an effective modulus of elasticity that is lower than the inherent modulus of elasticity of the first layer. In some embodiments, the analyte sensor senses an analyte selected from the group comprising glucose, galactose, fructose, lactose, peroxide, cholesterol, amino acids, alcohol, lactic acid, and mixtures of the foregoing. In some embodiments, the plurality of modifications are a plurality of perforations.
Additional embodiments of the invention are directed to a medical device that comprises an analyte an analyte sensor and an adhesive system. In some embodiments, the adhesive system comprises at least one layer having a material with a top and a bottom having a bottom perimeter, a first adhesive on the bottom for at least partially attaching to skin, a first inherent modulus of elasticity, a plurality of modifications therein that result in the first layer having an effective modulus of elasticity that is lower than the first inherent modulus of elasticity, and a second adhesive that is more aggressive than the first adhesive, the second adhesive along only the bottom perimeter. In some embodiments, the plurality of modifications are a plurality of perforations. In some embodiments, the analyte sensor senses an analyte selected from the group comprising glucose, galactose, fructose, lactose, peroxide, cholesterol, amino acids, alcohol, lactic acid, and mixtures of the foregoing.
In some embodiments the invention is directed to an apparatus that comprises a medical device and an adhesive system. Embodiments of the adhesive comprise a first layer including a first layer material having a top and a bottom having a bottom perimeter and a first layer adhesive on the bottom for attaching to skin where the first layer has an inherent modulus of elasticity, and a second adhesive that is more aggressive than the first layer adhesive where the second adhesive is included along only the bottom perimeter. In some embodiments, the first layer includes a plurality of modifications therein that result in the first layer having an effective modulus of elasticity that is lower than the inherent modulus of elasticity of the first layer. In some embodiments, the medical device is a body wearable medical device. In some embodiments, the plurality of modifications are a plurality of perforations.
Additional embodiments of the invention are directed to an apparatus that comprises a medical device and an adhesive system. In some embodiments, the adhesive system comprises at least one layer having a material with a top and a bottom having a bottom perimeter, a first adhesive on the bottom for at least partially attaching to skin, a first inherent modulus of elasticity, a plurality of modifications therein that result in the first layer having an effective modulus of elasticity that is lower than the first inherent modulus of elasticity, and a second adhesive that is more aggressive than the first adhesive, the second adhesive along only the bottom perimeter. In some embodiments, the plurality of modifications are a plurality of perforations. In some embodiments, the medical device is a body wearable medical device such as, for example, a pump for the delivery of therapeutic drugs.
The above-mentioned aspects, as well as other features, aspects, and advantages of the present technology will now be described in connection with various embodiments, with reference to the accompanying drawings. The illustrated embodiments, however, are merely examples and are not intended to be limiting. Throughout the drawings, similar symbols typically identify similar components, unless context dictates otherwise. Note that the relative dimensions of the following Figures may not be drawn to scale.
The disclosed and described technology relates to single layer and multilayer adhesive systems. The adhesive systems described herein include at least one layer of material having some type of modification therein that reduces the modulus of elasticity of that material. Additionally, the adhesive systems can include a ring of an aggressive adhesive such as, for example, a hydrocolloid, around its bottom perimeter that is to contact skin.
Disclosed herein are embodiments of a multilayer composite adhesive system, configured to adhere, in some embodiments, to an body wearable device, such as, for example, opto-enzymatic analyte sensors that can be used to measure, for example, glucose, galactose, fructose, lactose, peroxide, cholesterol, amino acids, alcohol, lactic acid, and mixtures of the foregoing, to the surface of skin. The multilayer composite adhesive systems disclosed herein can attach to the bottom of the body wearable device housing thereby allowing the device to be attached to the skin for an extended period of time, for example, 4 to 7 days, 7 to 10 days, 10 to 14 days or 14 to 21 days.
Embodiments of the adhesive systems disclosed and described herein can be used to attach any medical device or medical appliance to the skin. Example medical devices and medical appliances include, and are not limited to, analyte sensors, pumps for the delivery of therapeutic drugs (insulin, chemotherapy drugs, etc.), and any other body wearable medical device or appliance as will be readily understood by those of skill in the art. In some embodiments, the adhesive systems disclosed and described herein can be used for wound care. Example wound care uses include, and are not limited to, tapes to attach wound dressings to skin, bandages, and any other wound care use as will be readily understood by those of skill in the art.
In order to achieve the required sustained attachment to the skin while allowing the adhesive system have a high moisture vapor transmission rate (“MVTR”) and to be easily removed from the skin when desired, embodiments of the present invention are directed to multilayer composite adhesive systems where the properties of the layers combine to form a system with a high MVTR that addresses the mismatch/differences in the mechanical properties between the skin and the adhesive system, i.e., stress/strain differentials that exist between skin and the adhesive systems and that uses a skin adhesive that provides sufficient adhesion to skin while allowing the adhesive system to be easily removed with little pain. Thus, each layer of the present adhesive systems can have different mechanical and material properties but when the properties of all layers are combined, they address the issues with prior systems by mimicking skin mechanics in order to address the strain mismatch between the skin and the adhesive system while providing a high MVTR.
To satisfy these requirements, the multilayer composite adhesive systems of the embodiments of the present invention have been designed to have a high MVTR and a low, effective Young's/elastic modulus. Further, the system can plastically deform when worn on the skin and has good adhesion to skin while being easily removed from the skin when desired. The MVTR of a material can be an inherent property of the material or a material's MVTR can be changed/adjusted by altering the material to include, for example, openings, slits, cuts or other perforations (collectively, “perforations”) therein, resulting in a material that has a higher effective MVTR, thereby providing a pathway for moisture to escape through the material. As used herein, (1) “inherent” shall mean a property of an unmodified material or layer or multilayer material and (2) “effective” shall mean the resulting property after a material or layer or multilayer adhesive system has been modified, for example, as disclosed herein to include modifications such as perforations or the resulting properties of a multilayer adhesive system constructed in accordance with the embodiments disclosed herein.
A material typically plastically deforms when its linear elastic force is exceeded as stress is developed in the material. Similar to a material's MVTR, a material's elastic modulus can be an inherent property of the material or it can be changed/adjusted by modifying the material to include, for example, perforations therein, resulting in a material that has an effective elastic modulus that is lower than its inherent elastic modulus. The shape, orientation, size and spacing of these perforations, can also be used to change a material's elastic in different directions, i.e., the web and cross-web directions of the material, depending on the size, orientation and spacing of the perforations.
For example, as discussed in detail below, a material that includes perforations that are longer in length than the gap/spacing between adjacent perforations will have a lower effective elastic modulus than a material that includes perforations that are shorter in length than the gap/spacing between adjacent perforations. Using perforations that have different lengths and spacing between in different directions allows tuning of the modulus of elasticity in the different directions, i.e. a first modulus of elasticity in a first direction and a second modulus of elasticity in a second direction where the first and second elastic modulus's can be the same or different. As discussed in more detail below, the length of the perforations and the spacing between adjacent perforations can be adjusted to tune the effective elastic modulus of the materials/layers and hence, the effective modulus of the embodiments of the adhesive systems disclosed and described herein. For example, the effective elastic modulus of an individual layer or the constructed multilayer adhesive system can be tuned/adjusted to be less than approximately 100 Kpa, 90 Kpa, 70 Kpa, 60 Kpa, 50 Kpa, 40 Kpa, 30 Kpa, 20 Kpa, and 10 Kpa, at 100% strain.
Thus, embodiments of the present adhesive systems have been designed to have a high MVTR and low elastic modulus, i.e., designed to have low elasticity, that undergo plastic deformation at low strains. Having an adhesive system that plastically deforms when attached skin, allows the system to use a less aggressive adhesive to attach the adhesive system to the skin as the shear forces between the adhesive and the skin are significantly reduced after the adhesive system plastically deforms. Adhesive systems that plastically deform when worn on the skin, solves the issue of edge peel and results in an adhesive system that remains attached to the skin for an extended period of time, for example, five (5) weeks.
The multilayer, composite adhesive system embodiments disclosed herein are also advantageous as they permit different system designs based on the intended use of the system while allowing one to design the system to have the required MVTR and elastic modulus properties. For example, one may desire to have an adhesive system with moisture wicking properties, or one may desire to have an adhesive system to absorb bodily fluid such as in the form of a bandage, or one may desire to an adhesive system with sufficient strength to attach medical devices and other medical items to the body. Different uses may require different properties or a combination of properties, which can be achieved through the use of layers of different materials, which individually may not meet the intended use requirements but when modified as discussed herein and combined, provide the required properties.
Material properties to consider in designing adhesive system embodiments of the present invention include, and are not limited to, Young's modulus, MVTR, hydrophobicity, hydrophilicity and moisture wicking, adhesive strength, adhesive hypoalgernicity and intact adhesive system removal.
Turning first to the coin standard 2810, in some examples the coin standard 2810 is attached to the skin. The surface of the coin standard 2810 can be composed of an acrylate pressure sensitive adhesive on a PET release. The pressure sensitive adhesive allows the coin standard 2810 to adhere to the skin when pressure is applied—thereby activating the adhesive without the use of a solvent, water or heat. The material of the coin standard 2810 can be composed of a spun lace non-woven material with a high MVTR. In some examples, the coin standard 2810 can have a thickness of 4 mm.
As illustrated in
Turning next to the outer ring 2820, in some examples, the outer ring 2820 is composed of a re-attachable pressure sensitive adhesive. The outer ring 2820 can be composed of a lined silicon/silicon pressure sensitive adhesive on a PTFE release.
In some examples, the outer ring 2820 can be joined to the coin standard 2810. The attachment between the two layers can form a gap 2822. The outer ring 2820 can be attached to the coin standard 2810 with acrylate pressure sensitive adhesive. In some examples, the acrylate pressure sensitive adhesive can be a polyurethane acrylate (P-UR acrylate). In some embodiments, the release liner of the outer ring 2820 is formed from a patterned PET and PTFE pattern. The PET can be bonded to the PTFE below the coin and the PTFE below the silicon. In some examples, the outer ring 2820 can have a base width of 30 mm and a length of 40 mm. In some embodiments, outer ring 2820 can have a width of between approximately 3 mm and 10 mm and a thickness between approximately 0.025 mm and 0.1 mm.
In other examples, the bottom layer 2844 can be a spun lace, non-woven material that includes a plurality of cuts or gaps 2856 therein that divide the bottom layer 2844 into an outer ring 2850, a middle ring 2852 and a central portion 2854. In this embodiment, the bottom layer adhesive 2844 can be more aggressive than the top layer adhesive 2842.
In another embodiment, the outer annular region 2850 can be a re-attachable bio-compliant skin adhesive connected to the top layer 2840 of the adhesive system 2860. The outer annular region 2850 can have a central portion 2854 of spun lace, non-woven material. The outer annular region 2850 may also have an additional adhesive layer above the central portion 2854 of spun lace, non-woven material. In other examples, the outer annular region 2850 can have the same materials as the central portion 2854. As well, the outer annular region 2850 can have an adhesive connected to the top layer 2840 of the adhesive system 2860.
In some examples, the adhesive system 2860 includes a top layer 2850 that can be a backing material that has a high MVTR, such as polyurethane. In some examples, the backing material is thin and complaint. In some embodiments, as illustrated in
In another embodiment of the adhesive system 2860 depicted in
In the herein disclosed embodiments, dividing the bottom layer of the adhesive system into multiple annular regions or other discontinuous portions, helps to minimize the strain on the inner or central regions of the adhesive system by distributing stress across the annular regions or discontinuous portions. Adhesive systems constructed in this manner, create a stress-strain gradient between the inner or central regions and the ring or discontinuous portions that extend away from the inner or central regions. For example, the embodiment of the adhesive system depicted in
In some examples, the adhesive system 2800 is re-sealable and provides for comfortable adhesion. The illustrated adhesive system 2800 can include two zones of attached materials. In some embodiments, the outer layer can be elastic, with a low durometry. The outer layer can allow the adhesive system 2800 and attached device to be re-sealable to the skin. In some embodiments, the inner layer can be composed of a material that is less elastic but has a high MVTR. As will be discussed in further detail below, the material properties of the inner layer can allow the skin to breath by allowing water and/or water vapor to evaporate off the surface of the skin.
Depicted in
The plurality of perforations 6008, 6012 transform the top layer material from a material having a high or first inherent elastic modulus and/or a low inherent MVTR into a material having an effective lower or second elastic modulus and/or an effective higher MVTR. The effective low elastic modulus is achieved by creating stress relaxing perforations that expand as the material is stretched. As the perforations expand, a plurality of concentrated areas of stress 6016 develop between adjacent perforations 6008, 6010, that undergo plastic deformation when stress is applied to the top layer 6004. Because any stress that is applied to the top layer 6004 is concentrated in areas 6016, these concentrated areas of stress 6016 plastically deform under external loads that are lower than stress that would cause an unmodified top layer 6004 material to plastically deform. This plastic deformation provides further strain relief between the top layer 6004 and the skin. The stress becomes lower for a given strain after deformation. Although the perforations 6008, 6012 in this embodiment are shown in a cross-hatch orthogonal pattern, the perforations 6008, 6012 can have any shape or pattern as long as they allow the material to separate creating a low elastic modulus response and preferentially create concentrated areas of stress 6016 between adjacent perforations. Additionally, in some embodiments, the plurality of perforations 6008, 6012 may extend completely through the top layer 6004 material while in other embodiments, they may not extend completely through the thickness of the material/layer and instead may be recessed, indented or embossed portions that fail when under stress and create the concentrated areas of stress 6016 between adjacent indentations causing the material layer to plastically deform under stress when applied to skin. In some embodiments, the top layer 6004 is a polyurethane material. In some embodiments, the top layer is a silicone elastomer.
The bottom layer 6006 can comprise any material (wicking materials, adhesives, etc.) and the material should be chosen based on the intended use of the adhesive system. In some embodiments, the material for the bottom layer 6006 is a wicking material such as, for example, a spun lace non-woven material, that includes an adhesive for adhering the bottom layer 6006 to skin. The wicking material of the bottom layer 6006, which contacts the skin, transports moisture laterally from areas of high moisture to areas of low moisture. As illustrated in
As illustrated in the figures, the top layer 6004 is attached to the bottom layer 6006 with the first layer adhesive thereby sandwiching the bottom layer 6006 between the top layer 6004 and the skin when the adhesive system 6000 is attached to the skin. In this embodiment, because the perforations 6018 extend through the entire thickness of the bottom layer 6006, which create discontinuous portions 6020 that are adjacent to one another, the bottom layer 6006 typically has a lower effective elastic modulus than the top layer 6004. Therefore, the top layer 6004 provides structural reinforcement for the bottom layer 6004 and holds the adhesive system 6000 together.
As depicted in
In some embodiments, the top layer adhesive used to attach the top layer 6004 to the bottom layer 6006 and the portions 6026 of the top layer that extend beyond the perimeter 6022 of the bottom layer 6006 to the skin, is a more aggressive adhesive than the bottom layer adhesive. This more aggressive adhesive is necessary to keep the top layer attached to the bottom layer 6006 and the skin when stress is applied to the adhesive system 6000 due to movement (expansion and contraction) of the skin. That is, the top layer 6004 must expand and contract to the same extent as the skin in order to cause the perforations 6008, 6012 to open and preferentially induce formation of the concentrated areas of stress 6016 and hence, plastic deformation of the top layer 6004, thereby minimizing stress in the top layer 6004. Thus, the top layer 6004 must remain attached to the skin.
In addition to using an aggressive adhesive to impart a higher initial and sustained bond strength between the portions 6026 of the top layer 6004 that extend beyond the perimeter 6024 of the bottom layer 6006 that attach to the skin with the top layer adhesive, the area of the portions 6026 of the top layer 6004 that extend beyond the perimeter 6024 of the bottom layer 6006 can be increased such that a larger area of the top layer 6004 is attached to the skin with the top layer adhesive. The increased area of the top layer 6004 that adheres to the skin allows a less aggressive adhesive to be used while keeping the adhesive system 6000 attached to the skin and causing the adhesive system 6000 to plastically deform under the stress imparted due to movement of the skin.
In additional embodiments of a two-layer adhesive system according to the present invention, as depicted in
Depicted in
In the embodiment depicted in
As depicted in
In another embodiment of the three-layer adhesive system 6600, as depicted in
In the embodiment depicted in
In the three-layer adhesive system embodiments 6500, 6600 depicted in
As previously disclosed, the length of the perforations 6008, 6012 and the spacing between adjacent perforations in the embodiments of the adhesive systems disclosed herein, can be changed/adjusted to tune the effective elastic modulus of the materials/layers and hence, the effective modulus of the completed multilayer adhesive systems.
As illustrated in
Although the plurality of perforations in the disclosed embodiments are shown in a cross-hatch pattern or are orthogonal to one another, any pattern of a plurality of perforations that create concentrated areas of stress in a layer or multilayer adhesive system, may be used. The type of patterned perforations used will affect the effective elastic modulus of the layer and/or adhesive system.
Modifying L1, L2, L3, and LA as outlined above, allows the effective elastic modulus of an individual layer or the constructed multilayer adhesive system to be tuned/adjusted to be less than approximately 100 Kpa, 90 Kpa, 70 Kpa, 60 Kpa, 50 Kpa, 40 Kpa, 30 Kpa, 20 Kpa, and 10 Kpa, at 100% strain. Thus, modifying the individual layers or the constructed multilayer adhesive system as outlined above, allows the effective elastic modulus to be maintained for strains up to 0.4 and preferably, up to 1.0.
In some embodiments of the two-layer adhesive systems disclosed herein, the top layer can have an effective elastic modulus less than 0.02 Mpa (20 Kpa) that is maintained for strains up to 0.4 and preferably, for strains up to 1.0. In some embodiments, the bottom layer can have an effective elastic modulus less than 0.02 Mpa (20 Kpa) that is maintained for strains up to 0.4 and preferably, for strains up to 1.0. In some embodiments, the two-layer adhesive system can have an effective elastic modulus less than 0.02 Mpa (20 Kpa) that is maintained for strains up to 0.4 and preferably, for strains up to 1.0. In some embodiments, the concentrated areas of stress plastically deform when an external load is applied to achieve a net strain of up to 0.4 in the two-layer adhesive system. In some embodiments, when the multilayer adhesive system is deformed by an external load to a strain of up to 0.4, the multilayer adhesive system deforms resulting in >90% of the achieved strain being retained when the external load is removed.
In some embodiments of the three-layer adhesive systems disclosed herein, the top layer can have an effective elastic modulus less than 0.02 Mpa (20 Kpa) that is maintained for strains up to 0.4 and preferably, for strains up to 1.0. In some embodiments, the middle layer can have an effective elastic modulus less than 0.02 Mpa (20 Kpa) that is maintained for strains up to 0.4 and preferably, for strains up to 1.0. In some embodiments, the bottom layer can have an effective elastic modulus less than 0.02 Mpa (20 Kpa) that is maintained for strains up to 0.4 and preferably, for strains up to 1.0. In some embodiments, the three-layer adhesive system can have an effective elastic modulus less than 0.02 Mpa (20 Kpa) that is maintained for strains up to 0.4 and preferably, for strains up to 1.0. In some embodiments, the concentrated areas of stress plastically deform when an external load is applied to achieve a net strain of up to 0.4 in the two-layer adhesive system. In some embodiments, when the multilayer adhesive system is deformed by an external load to a strain of up to 0.4, the multilayer adhesive system deforms resulting in >90% of the achieved strain being retained when the external load is removed.
Depicted in
The following seven adhesive systems were tested. Set 1 comprised an adhesive system having an unmodified polyurethane top layer. At 25% strain, the elastic modulus was approximately 15 Kpa and at 40% strain, the elastic modulus was approximately 14 Kpa. Set 2a comprised an unmodified polyurethane top layer and an unmodified hydrocolloid bottom layer. At 25% strain, the elastic modulus was approximately 15 Kpa and at 40% strain, the elastic modulus was approximately 16 Kpa. Set 2b comprised a modified polyurethane top layer and an unmodified hydrocolloid bottom layer. At 25% strain, the elastic modulus was approximately 10 Kpa and at 40% strain, the elastic modulus was approximately 10 Kpa. Set 3a comprised an unmodified polyurethane top layer and an unmodified adhesive backed spun lace, non-woven bottom layer. At 25% strain, the elastic modulus was approximately 44 Kpa and at 40% strain, the elastic modulus was approximately 38 Kpa. Set 3b comprised an unmodified polyurethane top layer, an unmodified adhesive middle layer and an unmodified adhesive backed spun lace, non-woven bottom layer. At 25% strain, the elastic modulus was approximately 64 Kpa and at 40% strain, the elastic modulus was approximately 51 Kpa. Set 4a comprised a modified polyurethane top layer and a modified adhesive backed spun lace, non-woven bottom layer. At 25% strain, the elastic modulus was approximately 25 Kpa and at 40% strain, the elastic modulus was approximately 0 Kpa. Set 4b comprised a modified polyurethane top layer, a modified adhesive middle layer and a modified adhesive backed spun lace, non-woven bottom layer. At 25% strain, the elastic modulus was approximately 22 Kpa and at 40% strain, the elastic modulus was approximately 19 Kpa.
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Once the skin 6001 is unstressed or returned to its relaxed state, which is depicted in
In addition, this reduction in shear forces/stress after plastic deformation, permits the use of an adhesive that has a high initial bond strength with a lower sustained bond strength, which results in adhesive systems that are easy to remove with less pain and that are able to be removed as an intact system (in one piece).
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To lower the effective elastic modulus of the single layer of material 7002, the single layer of material 7002 can be modified, for example, to include a plurality of modifications, such as, for example, a plurality of perforations 7006 that extend through the thickness of the spun lace, non-woven material 7003 and which can also extend through the adhesive 7004. Additionally, in some embodiments, the ring-shaped perforations 7006 may extend completely through the single layer of material 7002 while in other embodiments, they may not extend completely through the thickness of the material/layer 7002 and instead may be recessed, indented or embossed portions that fail when under stress thereby creating the through cut perforations 7006. As disclosed and described with respect to the previous adhesive system embodiments, the perforations 7006 can be any openings, slits, cuts or other perforations that can open up as discussed below.
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In some embodiments, the distance 7010 between all adjacent rings 7008 is the same while in some embodiments, the distance 7010 between adjacent rings 7008 varies. The distance 7010 between adjacent rings 7008 also effects the elastic modulus of the single layer of material 7002. For example, a smaller distance 7010 between adjacent rings 7008 allows more rings 7008 and hence, more perforations 7006, to be included for the adhesive system. The higher the number of rings 7008 that are included, the lower the effective elastic modulus of the system.
The plurality of ring-shaped perforations 7006 transform the single layer of material 7002 from a material having a high or higher elastic modulus and/or a low or lower inherent MVTR into a material having an effective low or lower elastic modulus and/or an effective high or higher MVTR. The effective lower elastic modulus is achieved because when the adhesive system 7000 is attached to skin for example, the strain that is applied to or generated on the adhesive system 7000 as a result of skin movement (stretching/compressing), results in a lower stress on the adhesive system 7000 due to the opening or expansion of the plurality of perforations 7006 as depicted in
In addition to the number of rings 7008 of perforations 7006 that are included and the spacing/distance 7010 between adjacent rings 7008 effecting the effective elastic modulus of the single layer of material 7002, as depicted in
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Although the plurality of perforations 7006 in the disclosed embodiments are shown as ring-shaped or circular, any pattern of a plurality of perforations that allow the perforations 7006 to open/expand under strain, may be used. For example, the plurality of perforations 7006 can be arranged in a series of parallel linear rows 7050 where the perforations 7006 in adjacent rows are offset from each other as depicted in
Constructing an adhesive system to have a more aggressive adhesive (hydrocolloid 7005 in some embodiments) along its bottom perimeter than on its interior/inner bottom region 7012, helps the system to resist edge peel resulting in an adhesive system that remains attached to the skin for extended periods of time, for example, 21 days or more. The more aggressive adhesive along the bottom perimeter of the adhesive system helps to prevent edge peel while the interior/inner bottom region 7012, which has been modified to mimic skin mechanics in order to address the strain mismatch between the skin and the adhesive system, decrease the shear forces across the adhesive system, which reduces the need for a more aggressive adhesive on the interior/inner region 7012 to address the shear forces. The aggressiveness of the adhesion along the outer perimeter of the adhesive system can also be controlled by the width 7014 of the more aggressive adhesive 7005. That is, a wider aggressive adhesive 7005 along the bottom perimeter will result in a more aggressive adhesion of the adhesive system along its perimeter, which will further reduce edge peel. Such a design results in an adhesive system that (1) can remain attached to skin for extended periods of time and (2) is less irritating to the wearer and easier and less painful to be removed.
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All adhesive systems tested and included in Table 1 were comprised of a single layer of nonwoven material available from Vancive™ Medical Technologies under the name MED 5750A and had a construction similar to that depicted in
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Adhesive systems having an elastic modulus (whether inherent or effective) that is either within the elastic modulus range of skin or lower than the elastic modulus of skin, perform better. That is, these adhesive systems experience less edge peel and remain attached to skin for longer periods of time than adhesive systems that have not been designed to ameliorate the strain mismatch between skin and the adhesive system resulting in adhesive systems that mimic the mechanical properties of human skin.
Although, the adhesive systems included in Table 1 demonstrate an effective elastic modulus when the pull direction is orthogonal to the orientation of the perforations, those of skill in the art will readily understand that arranging the perforations in a circular or ring pattern as depicted in
Additional embodiments can include an adhesive system 7020 that includes multiple layers of material having a more aggressive adhesive, such as for example a hydrocolloid, ring around its bottom perimeter, than the adhesive on its interior bottom portion. As depicted in
Adhesive systems can be designed to include any number of layers of material with a at least a portion of its bottom surface in contact with skin including a more aggressive adhesive. That is, in some embodiments, the adhesive system can include at least one layer that comprises a single layer of material with an adhesive and a more aggressive adhesive on at least a portion of its bottom surface as disclosed and described with respect to
In some embodiments, the number of rings 7008 or rows 7050 of perforations 7006, density of perforations 7006, distance 7010/D1 between adjacent rings 7008 or rows 7050 of perforations 7006, length L10 of perforations 7006, and or distance L11 between perforations 7006 in different portions or areas of the same adhesive system, can be adjusted/varied in order to change the effective elastic modulus of different areas/portions of the adhesive system. Thus, adhesive systems can be designed to include multiple effective elastic moduli, which can allow adhesive systems to be designed for attachment to specific areas of the human body.
As previously disclosed, adhesive systems disclosed and described herein, can be used to attach medical devices and medical appliances to the skin. In some examples, the bottom of the device housing 2832 can have channels or other disruptions 2845 that allow air flow under the device housing and also allow moisture to flow away from the skin and adhesive system 6000/7000/7020. The device can therefore be bonded to the underlying adhesive system 6000 in a disrupted manner. The device can be attached to the adhesive system 6000/7000/7020 in a plurality of ways. For example, the device housing 2832 can be attached to the adhesive system 6000/7000/7020 using heat staking, an adhesive layer (e.g. device adhesive 2830 discussed above or any other type of adhesive) or through ultrasonic welding.
Turning briefly to the embodiments of the adhesive systems illustrated in
It is to be understood that the embodiments of the invention described herein are not limited to particular variations set forth herein as various changes or modifications may be made to the embodiments of the invention described and equivalents may be substituted without departing from the spirit and scope of the embodiments of the invention. As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features that may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the embodiments of the present invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process act(s) or step(s) to the objective(s), spirit or scope of the embodiments of the present invention. All such modifications are intended to be within the scope of the claims made herein,
Moreover, while methods may be depicted in the drawings or described in the specification in a particular order, such methods need not be performed in the particular order shown or in sequential order, and that all methods need not be performed, to achieve desirable results. Other methods that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional methods can be performed before, after, simultaneously, or between any of the described methods. Further, the methods may be rearranged or reordered in other implementations. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products. Additionally, other implementations are within the scope of this disclosure.
Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include or do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments.
Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.
Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “an,” “said” and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.
It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, if an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element could be termed a second element without departing from the teachings of the present invention.
Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than or equal to 10% of, within less than or equal to 5% of, within less than or equal to 1% of, within less than or equal to 0.1% of, and within less than or equal to 0.01% of the stated amount. If the stated amount is 0 (e.g., none, having no), the above recited ranges can be specific ranges, and not within a particular % of the value. Additionally, numeric ranges are inclusive of the numbers defining the range, and any individual value provided herein can serve as an endpoint for a range that includes other individual values provided herein. For example, a set of values such as 1, 2, 3, 8, 9, and 10 is also a disclosure of a range of numbers from 1-10, from 1-8, from 3-9, and so forth.
Some embodiments have been described in connection with the accompanying drawings. The figures are drawn to scale, but such scale should not be limiting, since dimensions and proportions other than what are shown are contemplated and are within the scope of the disclosed inventions. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with various embodiments can be used in all other embodiments set forth herein. Additionally, it will be recognized that any methods described herein may be practiced using any device suitable for performing the recited steps.
While a number of embodiments and variations thereof have been described in detail, other modifications and methods of using the same will be apparent to those of skill in the art. Accordingly, it should be understood that various applications, modifications, materials, and substitutions can be made of equivalents without departing from the unique and inventive disclosure herein or the scope of the claims.
This application is a National Stage Entry Application of PCT/US2017/067824, filed Dec. 21, 2017, which claims the benefit of U.S. Provisional Application No. 62/439,132, filed Dec. 26, 2016, the entire contents of each of these applications are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2017/067824 | 12/21/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62439132 | Dec 2016 | US |
