具体实施方式：
[0019]The present invention relates to systems for the administration of active substances to the skin of a consumer and methods employing the system. The following description is presented to enable one of ordinary skill in the art to make and use the invention. Various modifications to the embodiments and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the features described herein.
[0020]As used herein the specification and the claims, the term “topical” and variants thereof mean of or applied to an isolated part of the body. This includes, without limitation skin, mucosa, and enamel.
[0021]As used herein, “benefit agent” means an ingredient or material that provides a benefit, e.g., improves, relieves, reduces, or treats symptoms or conditions of the skin, ether cosmetic or therapeutic.
[0022]The method for treating common consumer skin flaws described herein uses an applicator having a three-dimensional shape corresponding to the isolated body part used in combination with a benefit agent containing membrane structure for delivery of benefiting agent substance in the membrane structure to the skin of the consumer, and methods of using the system. The three-dimensional conformal applicator has varying personalized area-specific treatment zones to enable the treatment application more effectively. With a three-dimensional conformal applicator matched to the individual user's body part profile as physical guides, the application becomes easier and more effective, and can help in locating specific target zones to the precise area for applications.
[0023]Referring to the drawings, FIGS. 1 and 2 are front and rear perspective views, respectively, of a first embodiment of a skin treatment system 10 which may be used in the present invention. FIG. 3 is a rear exploded view of system 10. Skin treatment system 10 includes applicator 20 having a first surface 22, and a second surface 24. In this embodiment, applicator 20 is shown as a facial mask.
[0024]Applicator 20 in this embodiment has eye openings 26, a nose opening 27, and a mouth opening 28, and is sized to cover the full face of the user. It is important to note that in other facial mask type embodiments, applicator 20 may be sized to partially cover the face of the user, and may be without any of the openings described above.
[0025]Disposed on second surface 24 of applicator 20 are active membranes 40a, 40b, 40c, and 40d. This plurality of active membranes is releasably disposed on second surface 24 of applicator 20, and contain one or more benefit agents. Active membranes 40a, 40b, 40c, and 40d have first surfaces and second surfaces. FIG. 3 shows first surface 42d of active membrane 40d, as well as second surfaces 44a, 44c, and 44d of active membranes 40a, 40c, and 40d, respectively. The bond between applicator 20 and active membranes 40a, 40b, 40c, and 40d occur between second surface 24 of applicator 20 and first surfaces of the active membranes.
[0026]Active membrane 40a is located in the forehead region of facial mask applicator 20, while active membranes 40b and 40c are located in the cheek region of facial mask applicator 20 and active membrane 40d is located in the chin region of facial mask applicator 20. Although the embodiment shown has an applicator 20 with four releasably disposed active membranes (40a, 40b, 40c, and 40d), other embodiments may have more or less releasably disposed membranes. Some embodiments may have one or more active membrane, or two or more active membranes, or four or more active membranes, or six or more active membranes, or eight or more active membranes, or twelve or more active membranes. The number and location of active membranes 40 depend on the common consumer skin flaw(s) being treated.
[0027]Active membranes 40 contain one or more benefit agents. In some embodiments, active membranes may contain two, three, four, or more benefit agents. Also, if there are two or more active membranes, each active membrane may contain the same beneficial agent(s), or each active membrane may contain different beneficial agent(s). In some embodiments, individual active membranes may contain more than one benefit agent. Also, different regions of the active membrane may contain different active agents, or may contain a gradient of active agent from one region to another. For example, the active agent may have a lower concentration proximate the edges to “feather” the treatment effect.
[0028]Active membranes 40 may also have a variety of shapes, depending on the location of skin treatment. Possible shapes of the footprint left by active membranes 40 include, but are not limited to, squares, rectangles, triangles, circles, ovals, kidneys, stars, crosses, characters, etc. The corners of such shapes, if any, may be angular or curved to reduce potential lift/removal points. The zone of the treatment could be greater than about 1,000 cm2, about 1,000 cm2, or about 100 cm2, or about 10 cm2, or about 1 cm2, or less than 1 cm2.
[0029]In use, skin treatment system 10 of the present invention will be disposed on the user's skin, and the applicator portion will be removed therefrom. FIGS. 4 and 5 are side cross sectional views of system 10 along the 4-4 plane of FIG. 1 disposed on a user's face prior to, as well as after, removal of the applicator portion of the system. The figures show sections of applicator 20 with first surface 22 and second surface 24, active membranes 40a and 40d with first surfaces 42a, 42d and second surfaces 44a, 44d, and user's face 50 with face surface 52. The sections of applicator 20 seen in the figures are those above nose opening 27, between nose opening 27 and mouth opening 28, and below mouth opening 28.
[0030]FIG. 4 shows that when skin treatment system 10 is disposed on the user's face 50, second surfaces 44a, 44d of active membranes 40a and 40d are in contact with surface 52 of face 50. Second surface 24 of applicator 20 remains in contact with first surfaces 42a, 42d of active membranes 40a and 40d until removed by the user. Removal of applicator 20 by the user results in the structure shown in FIG. 5. When applicator 20 is removed, second surfaces 44a, 44d of active membranes 40a and 40d remains in contact with surface 52 of face 50 at the treatment zone.
[0031]In accordance with a more particular aspect of the present invention, second surface 24 of applicator 20 releasably attaches to first surfaces 42a, 42d of active membranes 40a and 40d. The attachment strength of applicator 20 to active membranes 40a and 40d is less than the adhesive strength of membranes 40a and 40d to skin. So, when applicator 20 is removed by the user, active membranes 40a and 40d remains adhered to skin 50. In some embodiments, membranes 40a and 40d are held in place by spot application of adhesive.
[0032]In some embodiments, the shear strength of applicator 20 to active membranes 40a and 40d is less than the shear strength of membranes 40a and 40d to skin. So, when applicator 20 is removed by the user, active membranes 40a and 40d remains adhered to skin50.
[0033]In some embodiments, a plurality of releasable membranes is formed in a stack on the applicator surface of the applicator mask, each releasable membrane comprising one or more benefit agents disposed in one or more treatment zones of the applicator. The adhesion of the membrane to the isolated body part is greater than the adhesion of the membrane to the applicator surface and to an adjacent membrane in the stack.
[0034]FIGS. 6 and 7 are views of a second face embodiment of the system 100 of the present invention. FIG. 6 is a rear perspective, while FIG. 7 is a rear exploded view of system 100. The skin treatment system 100 includes applicator 120 having a first surface 122, and a second surface 124. In this embodiment, applicator 120 is shown as a facial mask.
[0035]Applicator 120 in this embodiment has eye openings 126, a nose opening 127, and a mouth opening 128, and is sized to cover the full face of the user. It is important to note that in other facial mask type embodiments, applicator 120 may be sized to partially cover the face of the user, and may be without any of the openings described above.
[0036]Disposed on second surface 124 of applicator 120 is membrane 130, which is releasably disposed on second surface 124 of applicator 120. Membrane 130 has a first surface 132, and a second surface 134, and has active regions 140a, 140b, 140c, and 140d which contain one or more benefit agents. The bond between applicator 120 and membrane 130 occurs between second surface 124 of applicator 120 and first surface 132 of the membrane 130.
[0037]Membrane 130 in this embodiment has eye openings 136, a nose opening 137, and a mouth opening 138, and is sized to cover the full face of the user. It is important to note that in other embodiments, membrane 130 may be sized to partially cover the face of the user, and may be without any of the openings described above.
[0038]In this embodiment, active region 140a is located in the forehead region of facial mask applicator 120, while active regions 140b and 140c are located in the cheek region of facial mask applicator 120 and active region 140d is located in the chin region of facial mask applicator 120. Although the embodiment shown has an applicator 120 having releasably disposed membrane 130 with four active regions (140a, 140b, 140c, and 140d), other embodiments may have membranes 130 with more or less active regions. Some embodiments may have one or more active regions, or two or more active regions, or four or more active regions, or six or more active regions, or eight or more active regions, or twelve or more active regions. The number and location of the active regions 140 depend on the common consumer skin flaw(s) being treated.
[0039]As mentioned earlier, active regions 140 contain one or more benefit agents. In some embodiments, active regions may contain two, three, four, or more benefit agents. Also, if there are two or more active regions, each active region may contain the same beneficial agent(s), or each active region may contain different beneficial agent(s).
[0040]Active regions 140 may also have a variety of shapes, depending on the location of skin treatment. Possible shapes of the active regions 140 include, but are not limited to, squares, rectangles, triangles, circles, ovals, kidneys, stars, crosses, characters, etc. The zone of the treatment could be greater than about 1,000 cm2, about 1,000 cm2, or about 100 cm2, or about 10 cm2, or about 1 cm2, or less than 1 cm2.
[0041]In accordance with a more particular aspect of the present invention, second surface 124 of applicator 120 releasably attaches to first surface 132 of membrane 130. The attachment strength of applicator 120 to membrane 130 is less than the adhesive strength of membrane 130 to skin. So, when applicator 120 is removed by the user, membrane 130 remains adhered to the skin at the location of the treatment zone.
[0042]FIGS. 8 and 9 are views of a third face embodiment of the system 200 of the present invention. FIG. 8 is a rear perspective, while FIG. 9 is a rear exploded view of system 200. The skin treatment system 200 includes applicator 220 having a first surface 222, and a second surface 224. In this embodiment, applicator 220 is shown as a facial mask.
[0043]Applicator 220 in this embodiment has eye openings 226, a nose opening 227, and a mouth opening 228, and is sized to cover the full face of the user. It is important to note that in other facial mask type embodiments, applicator 220 may be sized to partially cover the face of the user, and may be without any of the openings described above.
[0044]Disposed on second surface 224 of applicator 220 is membrane 230, which is releasably disposed on second surface 224 of applicator 220. Membrane 230 has a first surface 232, and a second surface 234. The bond between applicator 220 and membrane 230 occurs between second surface 224 of applicator 220 and first surface 232 of membrane 230.
[0045]Membrane 230 in this embodiment has eye openings 236, a nose opening 237, and a mouth opening 238, and is sized to cover the full face of the user. It is important to note that in other embodiments, membrane 230 may be sized to partially cover the face of the user, and may be without any of the openings described above.
[0046]Disposed on second surface 234 of membrane 230 are active membranes 240a, 240b, 240c, and 240d. In some embodiments, these active membranes are releasably disposed on second surface 234 of membrane 230, and contain one or more benefit agents. Active membranes 240a, 240b, 240c, and 240d have first surfaces and second surfaces. FIG. 9 shows first surface 242d of membrane 240d, as well as second surfaces 244a, 244c, and 244d of active membranes 240a, 240c, and 240d, respectively. The bond between membrane 230 and active membranes 240a, 240c, and 240d occur between second surface 234 of membrane 230 and first surfaces of the membranes.
[0047]In this embodiment, active membrane 240a is located in the forehead region of membrane 230, while active membranes 240b and 240c are located in the cheek region of membrane 230 and active membrane 240d is located in the chin region of membrane 230. Although the embodiment shown has a membrane 230 with four active membranes (240a, 240b, 240c, and 240d), other embodiments may have more or less active membranes. Some embodiments may have one or more active membranes, or two or more active membranes, or four or more active membranes, or six or more active membranes, or eight or more active membranes, or twelve or more active membranes. The number and location of the active membranes 240 depend on the common consumer skin flaw(s) being treated.
[0048]As mentioned earlier, active membranes 240 contain one or more benefit agents. In some embodiments, membranes may contain two, three, four, or more benefit agents. Also, if there are two or more active membranes, each active membrane may contain the same beneficial agent(s), or each active membrane may contain different beneficial agent(s).
[0049]Active membranes 240 may also have a variety of shapes, depending on the location of skin treatment. Possible shapes of the active membranes 240 include, but are not limited to, squares, rectangles, triangles, circles, ovals, kidneys, stars, crosses, characters, etc. The zone of the treatment could be greater than about 1,000 cm2, about 1,000 cm2, or about 100 cm2, or about 10 cm2, or about 1 cm2, or less than 1 cm2.
[0050]In accordance with a more particular aspect of the present invention, second surface 224 of applicator 220 releasably attaches to first surface 232 of membrane 230. The attachment strength of applicator 220 to membrane 230 is less than the adhesive strength of membrane 230 to skin. So, when applicator 220 is removed by the user, membrane 230 remains adhered to the skin at the location of the treatment zone.
[0051]It is important to note that although skin treatment systems 10, 100 and 200 in the embodiments of the present invention use applicators 20, 120 and 220 in the form of a facial mask, skin treatment systems may also be used on other isolated body parts, such as arms, hands, legs, or feet, for example. In these other embodiments, applicators 20, 120 and 220 will be shaped as appropriate for other isolated body parts.
[0052]Applicators 20, 120 and 220 are made of a flexible, biocompatible material which is capable of forming to the site of treatment on the skin of the consumer. There are numerous flexible, biocompatible material materials which may be used to form applicators. These materials include, but are not limited to: polyolefins like poly(ethylene) (PE) or poly(propylene) (PP); poly(tetrafluoroethylene) (PTFE); poly(vinyl chloride) (PVC); silicones like poly(dimethyl silane) (PDMS); polyacylates like poly(methyl methacrylate) (PMMA) or poly(hydroxyethyl methacrylate) (pHEMA); polyesters like poly(ethylene terephthalate) (PET), poly(glycolic acid) (PGA), poly-L-lactic acid (PLA), or polydioxanone (PDO); polyethers like polyether ether ketone (PEEK) or polyether sulfone (PES); polyamide (Nylon); or polyurethane (PU), polycaprolactone, or combinations of the above. The method of forming applicator 20 will be discussed later.
[0053]In accordance with a more particular aspect of the present invention, the attachment strength of the applicator to the membrane is less than the adhesive strength of the membranes to skin. So, when the applicator is removed by the user, the membrane remains adhered to the skin at the location of treatment zone.
[0054]This relative adhesive strength is provided by modifying the material of the applicator, at least on the second surface (24, 124, or 224) of the applicator (the surface that is directed toward the skin during use), or the first surface (42, 132, or 232) of the membrane (the surface that is directed away from the skin during use). Adding a tackifier to the material in the applicator or the membrane can increase the attachment strength between the two. The attachment strength between the applicator (20, 120 or 220) and the accompanying membrane (40, 130, or 240) is also affected by the surface texture of the surface of the applicator in contact with the membrane. Imparting a texture, such as a plurality of parallel grooves, a bead-blasted texture, and the like, can increase the attachment strength therebetween.
[0055]Membranes 40, 130, and 240 of the present invention are provided in forms that are comfortable to wear and readily removable after remaining in place for an extended period of time, e.g., at least half an hour, or at least one hour, or at least about six (6) to eight (8) hours, or at least about twelve (12) hours, or about twenty-four (24) hours, if desired. Membranes 40, 130, and 240 are readily removable either by low adhesion to skin, or upon application of water thereto. By readily removable upon application of water thereto, it is meant that the membrane structure may dissolve or disintegrate upon application of water to the membrane structure, such that it may be removed from the skin without scrubbing, or the like. In some embodiments, the membranes may lose adhesion over time and fall off of the sight. Membranes 40, 130, and 240 preferably are a topically-applied skin care film, patch, applique, etc. (hereinafter “film structure” for the sake of convenience, without intent to limit) that preferably is relatively flexible.
[0056]Membranes 40, 130, and 240 of the present invention preferably are relatively thin and flexible, as described in further detail below, so that they preferably readily conform to the user's skin and are comfortable to wear, both because of the flexibility and conformability, as well as from the thinness. Membranes 40, 130, and 240 of the present invention intended for extended wear preferably are also formed to be aesthetically elegant without either peeling, wrinkling, cracking, or appearing greasy or tacky, or otherwise unpleasant or unsightly in nature. Membranes 40, 130, and 240 preferably are formed with sufficient rigidity and integrity to be able to withstand normal use when on the skin. For instance, membranes 40, 130, and 240 of the invention preferably are formed with sufficient strength to stay intact on the skin when exposed to normal external forces that the skin may experience, e.g., rubbing of clothing, pillow, etc.
[0057]If desired, membranes 40, 130, and 240 of the present invention may be formed to have structural integrity. As used herein, structural integrity is to be understood as the physical capability of the membranes to maintain a substantially monolithic form or structure and to resist tearing or fracture while being manipulated independent of the applicator.
[0058]It will be appreciated that structural integrity of membranes 40, 130, and 240 of the present invention preferably also contributes to the membranes' ability to remain intact during manipulation and use, and to conform to the contours of the application site to which they are applied, as discussed in further detail below. For instance, it is desirable that each membrane have sufficient structural integrity so that the membrane does not readily tear when manipulated, worn, or otherwise used. It will be appreciated that selection of one or more film formers that contribute to a product's ability to achieve a pliable, cohesive, and continuous covering on an application site such as skin, is one manner of achieving the desired structural integrity of a membrane of the present invention. In some embodiments, selection of one or more plasticizers for producing or promoting plasticity and flexibility and reducing brittleness, is another manner of achieving the desired structural integrity of a membrane of the present invention.
[0059]The structural integrity of membranes 40, 130, and 240 of the present invention typically may be correlated with the tensile strength or modulus and thickness of their structure. In connection with the present invention, structural integrity typically increases as thickness and yield strength increase. However, such properties must be balanced with their effect on whether the membrane is comfortable to be worn, as discussed in further detail below. Tensile strength contributes to the structural integrity of membranes 40, 130, and 240 used in accordance with principles of the present invention for such purposes as handling and/or removing the membranes 40, 130, and 240 from the skin. Tensile strength affects, inter alia, whether the membrane resists being fractured when being handled and/or removed from the skin. For instance, membranes 40, 130, and 240 of the present invention preferably have an elastic modulus of about 500 psi to about 10,000 psi. An elastic modulus of about 2,500 psi has been found in one embodiment to provide the desired stiffness to be comfortable during use. Typical samples with a ¾ inch (1.905 cm) width and a 0.1 mm thickness have a rupture-strength of about 2 lbf (pound force), although it will be appreciated that a useful range of rupture strengths is from about 0.5 lbf to about 5 lbf. The membrane's adhesion values are preferably between 225 gms/25 mm to 1500 gms/25 mm (8-50 oz/in). However, in some circumstances that will be recognized by the person of ordinary skill in the art, the adhesion values may be as large as 3000 gms/25 mm (100 oz/in). The shear values for the membrane are preferably greater than 250-500 minutes on a PSTC-107 (ASTM D3654)—procedure A.
[0060]The adhesion between the applicator and the membrane is preferably about 2-3 oz/in or 10-20% lower adhesion than the adhesion between the membrane and the topical surface to which it is applied (whichever is higher). If membranes are stacked in the applicator, a similar relation between adhesion of the body-contacting membrane to the topical surface and the adhesion of the body-contacting membrane to an adjacent membrane can be used.
[0061]The thickness of the membrane also affects structural integrity. For instance, the thickness of a membrane of the present invention may be between about 0.05 mm to about 2 mm, and preferably between about 0.05 mm and 0.3 mm. A thickness of approximately 0.1 mm has been found to provide the desired mechanical properties for handling, applying, and ultimately removing the membrane, such that the membrane maintains its structural integrity throughout such use, as well as while being worn on a given application site, as discussed in further detail below.
[0062]In accordance with one aspect of the present invention, membranes 40, 130, and 240 of the present invention are self-adhesive, i.e., the membrane adheres to a user's skin upon contact with the skin, preferably without additional steps, such as addition of another composition, such as water.
[0063]In one embodiment, water soluble bio adhesive polymers can be used for enhancing skin adhesive property. Examples useful for the invention include, but are not limited to, cellulose and its derivatives, polyvinyl pyrrolidone, water soluble celluloses, polyvinyl alcohol, ethylene maleic anhydride copolymer, methylvinyl ether maleic anhydride copolymer, acrylic acid copolymers, anionic polymers of methacrylic acid and methacrylate, cationic polymers with dimethyl-aminoethyl ammonium functional groups, polyethylene oxides, water soluble polyamide or polyester, polyethylene glycol, water soluble acrylic polymers, water soluble polyesters, hydroxyalkyl starches, casein, gelatin, solubilized proteins, polyacrylamide, polyamines, polyquaternium amines, styrene maleic anhydride resins, polyethylene amines, The water soluble carbohydrate can form hydrogen or covalent bonding to the water soluble or hydrophilic polymer in the membrane.
[0064]In accordance with one aspect of the present invention, the adhesive quality of membranes 40, 130, and 240 of the present invention are preferably capable of fixing the membrane to the skin of a user for an extended period of time, as discussed herein above, without irritating the skin. Preferably, the membrane is capable of adhering to the application site for as long as reasonable and/or indicated to have a membrane in place at such site. Thus, an upper temporal limit to adhesion time is not important, since the user or wearer typically will want to remove the membrane before the membrane would naturally wear off of the application site on its own. In embodiments where membranes 40, 130, and 240 are readily removable upon application of water thereto, the amount of time a membrane of the present invention is to adhere to a given application site is dictated by the amount of time the application area can withstand not being exposed to water. For instance, it will be appreciated that some surgical sites are not to be exposed to water for extended periods of time, such as several days. Membranes for application to such sites should accordingly be capable of adhering to such site for so long as the site is not exposed to water, if desired. As may be appreciated, the adhesive preferably is selected for application onto a skin surface which typically is not considered to be moist, in contrast with mucosal tissue. It will be appreciated that by being capable of adhering to the user's skin, the membrane simply is capable of adhering, but need not necessarily adhere if such property is not desired or unnecessary for a particular application.
[0065]Because membranes 40, 130, and 240 of the present invention preferably are formed to remain adhered to the application site for an extended period of time, as described above, non skin-contacting surfaces (first surfaces 42, 132, and 244 of membranes 40, 130, and 240, respectively), preferably have desirable properties and features to facilitate such an intended use of the membrane. For instance, because a membrane is designed to adhere to an application site, if the membrane is designed to adhere to an application site for an extended period of time, then an adhesive outwardly-facing surface may unintentionally or inadvertently adhere to another surface or object during use of the membrane. Such unintentional or inadvertent occurrence may cause the membrane to become dislodged, or, worse, disengaged (partially or even fully) from the application site. Moreover, it will be appreciated that an adhesive material typically attracts dust or dirt or other debris, which would likely be considered by the wearer to be unsightly and undesirable. Accordingly, it is preferable that non skin-contacting surfaces (first surfaces 42, 132, and 244 of membranes 40, 130, and 240, respectively) of the present invention are non-tacky; not adhesive, and create low or no static when rubbed. Thus, for membranes 40, 130, and 240 of the present invention, to remain adhered to an application site for an extended period of time, preferably have first surfaces 42, 132, and 244 that are non-tacky; non-adhesive.
[0066]If first surfaces 42, 132, and 244 rub against or are rubbed by something or otherwise contacts or is contacted by another surface or Membranes 40, 130, and 240, the membranes 40, 130, and 240 should not adhere to such surface or membrane.
[0067]Membranes 40, 130, and 240 may be tinted or pigmented to match the skin tone of the user so to be aesthetically pleasing, or at least not unaesthetic or unsightly, when worn.
[0068]Membranes 40, 130, and 240 may be formed to be clear to be discrete in situ. Further properties may be selected to render membranes 40, 130, and 240 of the present invention visually discrete when in situ so that if the membrane is worn during the day its noticeability is minimized as much as possible. For instance, the thinner the membrane is, the less visible the structure typically is. In addition, or alternatively, the color, texture (e.g., rough, slick, smooth, or otherwise textured such as an “orange peel” surface to match substantially the texture of the skin to which the membrane is applied so that the membrane is not starkly smooth relative to the skin with its natural imperfections), shine (shiny or dull depending on application site), etc., may be modified as desired to facilitate blending in of the membrane with the application site. Because membranes 40, 130, and 240 of the present invention may be configured to be worn for an extended period of time (e.g., more than an hour, such as described above, and/or even overnight), the membrane preferably is formed or configured to be comfortable when worn. A variety of factors (individually or in any combination) may be considered in achieving the desired comfort and level of comfort, including, without limitation, tactile properties, material thickness (affecting not only durability, but also weight on the application site), stiffness and permeability. Tactile properties that may contribute to comfort include smoothness, and/or stickiness of the adhesive used to adhere the membrane structure to a selected application site, etc. Additional tactile properties that may contribute to comfort include softness, smoothness, and texture of the membrane, such as determined by modulus of elasticity and coefficient of friction (rather than merely the aesthetic aspects of such properties).
[0069]Thickness affects a variety of additional factors, including stiffness—a stiffer membrane typically being less comfortable than a less stiff membrane. Material properties (a function of the composition of the material, independent of form) as well as structural properties (the form of the membrane) may affect the achievable comfort level of a membrane used in accordance with principles of the present invention when worn by a user. It will be appreciated that all the desired properties for a membrane used in accordance with principles of the present invention must be balanced, wherein some properties complementary, yet others have opposing dimensions. With regard to comfort, it will be appreciated that properties contributing to comfort must be balanced with properties contributing to structural integrity. There are at least three structural properties that affect “comfort”: flexibility (about a single, bending direction; generally, flexibility is considered a combination of thickness and flexural modulus), stretchability (in a single axial direction; generally, stretchability is considered a combination of thickness and elastic modulus), and conformability (generally considered a combination of flexibility and physical shape in multiple directions, about complex surface). Comfort may be achieved by minimizing both the thickness and the elastic modulus. It will be appreciated that flexibility and stretchability are both functions of the elastic modulus of the material. More particularly, flexibility generally is dictated by the thickness of the material as well as the flexural modulus. Stretchability is a function of thickness and elastic modulus. When the material is thicker, stiffness increases (which property correlates with comfort) and flexibility and stretchability are reduced, generally adversely impacting comfort. The elastic modulus generally affects how rubbery or brittle a material is, and is tied to comfort because it determines flexibility of the material. Increasing the flexural or elastic modulus of a material makes the material less flexible or stretchable, respectively. Specifically, a higher flexural or elastic modulu