The present invention relates generally to the field of a multi-layered sheet mask for provision of multiple cosmetic functions such as skin exfoliation, hydration, brightening, rejuvenation, treatment, anti-acne, anti-ageing, and anti-wrinkle. In particular, the present invention relates to a multi-layered sheet mask, a method of producing the multi-layered sheet mask, and a mould for producing the three-dimensional patterns of the porous first layer of the multi-layered sheet mask.
The human face is exposed to indoor and outdoor environments daily and directly. Many studies have been done to investigate how environmental factors such as temperature, humidity, sun exposure, and air pollutions levels could affect our facial skin. It has been observed that during warm weather, the facial skin tends to be oilier, and both dry and cold weathers could cause skin dryness and irritation. Unprotected facial skin tends to age and darken faster when subjected to long-term sun exposure. Therefore, to maintain the health of facial skin and to reduce the above-mentioned negative effects of skin exposure to a non-ideal environment, skincare is needed to prevent or mitigate such negative effects.
Among many facial skincare products, a sheet mask is one that comes commonly packaged for single use and is widely considered more hygienic, as compared to a reusable face mask that is packaged in a pot or tube. A sheet mask impregnated with cosmetic compositions can be used for moisturizing, oil removing, and improving the overall aesthetics of the face whilst providing user comfort. Although a sheet mask can provide multiple functions, the most important function is to ensure that the cosmetic compositions can be absorbed by the skin layers, especially the subcutaneous layers of the skin.
It is known that skin has three layers: the deeper subcutaneous tissue, the dermis, and the epidermis. The deeper subcutaneous tissue is made of fat and connective tissue. The dermis, atop the deeper subcutaneous tissue, contains tough connective tissues, hair follicles, and sweat glands. The epidermis is the outermost layer of the skin, providing a waterproof barrier and forms the skin tone.
Skin absorption is a route by which cosmetic compositions that are beneficial for facial skin can enter into the deeper layer of skin, and further into the body systemic circulation from the outer surface of the skin Absorption of cosmetic compositions through the skin is affected by a number of factors, such as concentration, duration of contact, solubility, physical condition of the skin, and the specific part of the body where the skin is located. However, one of the most important factors limiting skin absorption rate relates to the stratum corneum, which is the outermost layer of the epidermis layer of skin that acts as a barrier to protect underlying tissue from infection, dehydration, foreign substances, and mechanical stress. Therefore, how quickly cosmetic compositions can penetrate the stratum corneum determines the efficiency of skin absorption.
The stratum corneum is primarily composed of lipophilic cholesterol, cholesterol esters, and ceramides and generally has a thickness between 10 μm and 40 μm, comprising 15 to 20 layers of dead skin cells. Thus, lipid-soluble cosmetic composition can pass through the stratum corneum faster; however, as lipophilic molecules can only passively diffuse through the layers, the resultant lipid-soluble cosmetic composition that penetrates skin is mere to some minimal degrees.
In consideration of the above, exfoliation is necessary to improve the efficiency of skin absorption. Exfoliation is a process of removing dead skin cells from the epidermal layer of facial skin. Conventionally, exfoliation can be done in two ways: mechanical exfoliation and chemical exfoliation.
In mechanical exfoliation, a tool (e.g., a brush or a washcloth) or facial scrub physically removes the dead skin cells. Mechanical beads or exfoliating particles are mixed into a facial scrub cream or embedded in a membrane. This process involves physically scrubbing the skin with an abrasive. Mechanical exfoliators include microfiber cloths, adhesive exfoliation sheets, micro-bead facial scrubs, crepe paper, crushed apricot kernel or almond shells, sugar, or natural minerals like salt crystals, pumice, and abrasive materials such as sponges, loofahs, and brush-like needles. Facial scrubs are commonly available in over-the-counter products. However, persons with dry skin should avoid mechanical exfoliators which include a significant portion of pumice or crushed volcanic rock.
On the other hand, for chemical exfoliation, the chemical exfoliant comprises ingredients such as alpha- or beta-hydroxy acids (e.g., a facial wash with salicylic acid, or a peel pad with glycolic acid) to remove dead skin cells. Chemical exfoliants include facial wash or scrub containing salicylic acid, glycolic acid, fruit enzymes, citric acid, or malic acid which may be applied in high concentrations by a medical professional, or in lower concentrations in over-the-counter products. Chemical exfoliation that involves the use of products that contain alpha- or beta-hydroxy acids or enzymes acts to loosen a glue-like substance that holds the dead skin cells together, allowing the dead skin cells to be dislodged. This type of exfoliation is recommended for persons with acne condition or physical defects on the facial skin.
While there are cosmetic sheet masks with exfoliation function available on the market, they are made of sheets of even thickness. However, the thickness of the human facial skin is not homogenous. According to research conducted to examine the topographic thickness of facial skin, results show that the thickness of facial skin and the thickness of the epidermis layer of facial skin are not the same on one face. The thickest human facial skin is found at the lower third of the nose (specifically the lower nasal sidewall), and the thinnest facial skin is found at the medial aspect of the upper eyelid, while the thickest epidermis is found at the upper lip, and the thinnest epidermis is found at the posterior auricular region. Hence, a deeper exfoliation is needed at a thicker skin area of the face, so that the same quantity of cosmetic composition can be effectively absorbed as compared to a thinner skin area of the face. This is to ensure that a homogenous cosmetic effect can be effectively applied to the different areas of facial skin which is of varying skin thickness.
Further, most cosmetic sheet masks on the market have a single main function. Hence, to achieve multiple cosmetic functions on a facial skin, for instance exfoliation, hydration and ultraviolet-light protection, it would normally be required to take multiple separate steps, for example exfoliation followed by hydration followed by application of an ultraviolet-light protection serum, which may require multiple sheet masks and/or combination with other forms of cosmetic products.
Thus, there is a need to develop a multi-layered sheet mask that overcomes or at least ameliorates, one or more limitations with existing technologies. The multi-layered sheet mask is preferably one that has multiple functions and simultaneously targets skin surface composed of varying skin thickness. There is also a need to provide a method for preparing such a multi-layered sheet mask.
In one aspect, the present disclosure refers to a multi-layered sheet mask comprising at least
Advantageously, each layer of the multi-layered sheet mask may provide at least one cosmetic function to the facial skin. For example, the porous first layer of the multi-layered sheet mask may exfoliate the facial skin, causing the face to be brightened as the dead skin cells are removed. However, as exfoliation may cause minor forms of redness to appear on the facial skin, moisturization of the exfoliated skin is required which may be provided by the first active ingredient in the second layer of the multi-layered sheet mask. Further, the second layer of the multi-layered sheet mask may concurrently deliver active ingredients such as collagen via the microchannels to the dermis layer of the facial skin to stimulate collagen growth. After the facial skin has fully absorbed a moisturizing agent and a collagen growth stimulant, for example, an oil-based cosmetic such as facial oil as the second active ingredient, may be dispensed through the third layer of the multi-layered sheet mask to the facial skin. The active ingredients provided by the second and third layers of the sheet mask may be tailored according to the specific needs of the users.
Further advantageously, the multi-layered sheet mask may provide multiple cosmetic functions in a single mask, for instance, exfoliation and other cosmetic enhancement purposes may be achieved in one mask, as opposed to having to use several different single-layered masks. Hence, the multi-layered sheet mask offers more convenience and time efficiency as compared to use of several different single-layered masks.
Further advantageously, the multi-layered sheet mask may ensure higher penetration of active ingredients to the dermis layer of the facial skin due to the combined effects of exfoliation, where dead skin cells are removed for better absorption of active ingredients, and the delivery of active ingredients through the microchannels that penetrates the dermis layer of the facial skin.
Further advantageously, the multi-layered sheet mask may allow specific targeting of different zones of the facial skin by skin thickness or skin condition, thus allowing the multi-layered sheet mask to achieve enhanced cosmetic effects on specific users.
In another aspect, the present disclosure refers to a mould for producing the three-dimensional patterns of the porous first layer of the multi-layered sheet mask as disclosed herein, wherein the mould comprises a negative replica of the three-dimensional patterns.
Advantageously, the mould may be designed to comprise a negative replica of the three-dimensional patters of the porous first layer of the multi-layered sheet mask, which is dedicated for specific zones of the facial skin based on skin thickness and/or skin condition.
Further advantageously, the mould may allow the facile reproduction of complex micrometre-scale three-dimensional structures as exfoliators for cosmetic purposes.
In another aspect, the present disclosure refers to a method of producing a multi-layered sheet mask, the method comprising the steps of:
Further advantageously, the method may be adaptable to create additional layers, for example the fourth or fifth layers of mask, to offer additional cosmetic treatment for the facial skin. The method may also be adaptable to create multi-layered sheet mask for other parts of the body besides the face.
The following words and terms used herein shall have the meaning indicated:
The term “microchannel” as used herein refers to a channel with dimensions, such as length, diameter, width and height, in the micrometre scale, with a pointed tip on one end.
The term “pouch” as used herein refers to a pocket or bag for containing a liquid or gaseous substance.
The term “positive replica” as used herein refers to an exact structural copy of identical shape and contours. When a positive replica is used as a mould to create a structural product, the structural product will thus bear the shape and contours of a negative replica.
The term “negative replica” as used herein refers to an exact reverse structural copy of shape and contours. When a negative replica is used as a mould to create a structural product, the structural product will thus bear the shape and contours of a positive replica.
The term “UV-curable” as used herein refers to a material that can be treated by ultraviolet radiation to generate a crosslinked network of polymers, thus hardening or toughening in the process.
The term “prism” as used herein refers to a three-dimensional shape with two identical polygon bases facing each other, such that each polygon base can be a regular or irregular polygon.
Unless specified otherwise, the terms “comprising” and “comprise”, and grammatical variants thereof, are intended to represent “open” or “inclusive” language such that they include recited elements but also permit inclusion of additional, unrecited elements.
As used herein, the term “about”, in the context of concentrations of components of the formulations, typically means+/−5% of the stated value, more typically +/−4% of the stated value, more typically +/−3% of the stated value, more typically, +/−2% of the stated value, even more typically +/−1% of the stated value, and even more typically +/−0.5% of the stated value.
Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.
Exemplary, non-limiting embodiments of a multi-layered sheet mask will now be disclosed.
The multi-layered sheet mask comprises at least
The porous first layer and the porous support structure of the second layer may comprise a plurality of slits.
Advantageously, each layer of the multi-layered sheet mask may provide at least one cosmetic function to the facial skin. For example, the porous first layer of the multi-layered sheet mask may exfoliate the facial skin, causing the face to be brightened as the dead skin cells are removed. However, as exfoliation may cause minor forms of redness to appear on the facial skin, moisturization of the exfoliated skin is required which may be provided by the first active ingredient in the second layer of the multi-layered sheet mask. Further, the second layer of the multi-layered sheet mask may concurrently deliver active ingredient such as collagen via the microchannels to the dermis layer of the facial skin to stimulate collagen growth. After the facial skin has fully absorbed a moisturizing agent and a collagen growth stimulant, for example, an oil-based cosmetic such as facial oil as the second active ingredient, may be dispensed through the third layer of the multi-layered sheet mask to the facial skin. The active ingredients provided by the second and third layers of the sheet mask may be tailored according to the specific needs of the users.
Further advantageously, the multi-layered sheet mask may provide multiple cosmetic functions in a single mask, for instance, exfoliation and other cosmetic enhancement purposes may be achieved in one mask, as opposed to having to use several different single-layered masks. Hence, the multi-layered sheet mask offers more convenience and time efficiency as compared to use of several different single-layered masks.
Further advantageously, the multi-layered sheet mask may ensure higher penetration of active ingredients to the dermis layer of the facial skin due to the combined effects of exfoliation, where dead skin cells are removed for better absorption of active ingredients, and the delivery of active ingredients through the microchannels that penetrates the dermis layer of the facial skin.
Further advantageously, the multi-layered sheet mask may allow specific targeting of different zones of the facial skin by skin thickness or skin condition, thus allowing the multi-layered sheet mask to achieve enhanced cosmetic effects on specific users.
The multi-layered sheet mask may be a facial mask providing cosmetic care to a recipient of the multi-layered sheet mask. The multi-layered sheet mask may also be used as a mask on other parts of a recipient's body. The multi-layered sheet mask may be a hand mask, a foot mask or a body mask.
The multi-layered sheet mask may be designed to have a boundary edge so that during application of the mask, the active ingredients may not affect the natural orifice of the recipient or flow to contaminate areas of the recipient's body that do not need the active ingredients.
The porous first layer of the multi-layered sheet mask may have a first side and a second side, the first side contacting a facial skin (or a body part of a recipient).
The three-dimensional patterns may have an end integrated to the first side of the porous first layer of the multi-layered sheet mask or positioned within the porous first layer and the other end protruding from the first side toward the facial skin (or a body part of a recipient) when the air pouch is deflated.
The porous first layer and the three-dimensional patterns may be made of a material independently selected from the group consisting of synthetic, regenerated and natural biocompatible materials. The porous first layer may be made of a material which may be the same or different from the three-dimensional patterns.
The material may be selected from the group consisting of UV-curable polymer, UV-LED curable polymer, bioabsorbable polymer, cotton, nylon, nylon microfibre, regenerated cellulose fibre, cellulose, biocellulose, foil, hyaluronic acid, and hydrogel. The regenerated cellulose fibre may be Cupro, Tencel, Modal, Lyocell, Viscose or Rayon.
The UV-curable polymer may be polyvinyl alcohol.
The foil may be a gold foil. Masks that contain gold foil are able to trap heat to open up skin pores for superior delivery of the active ingredient(s). Normally, the foil is outside away from the facial skin (or a body part of a recipient) and the first layer (which can be soft cellulose or a similar material) is in contact with the facial skin (or a body part of a recipient) to deliver the active ingredient(s). The three-dimensional patterns can be cast on the inside of the first layer in contact with the facial skin (or a body part of a recipient).
When the material used is hyaluronic acid, the molecular weight of the hyaluronic acid may be varied to control the time for its dissolution. Hyaluronic acid (HA) includes hyaluronan or hyaluronate and its derivates and their application in cosmetic formulations. HA is a glycosaminoglycan constituted from two disaccharides (N-acetylglucosamine and D-glucuronic acid). HA may be crosslinked by using a photoinitiator such as lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (LAP). Another example is Hyaluronic Acid-aldehyde crosslinked with O,O′-1,3 propanediylbishydroxylamine dihydrochloride (POA) in the presence of standard HA. HA can have a wide range of molecular weights ranging from 20,000 to 10,000,000 Da. HA may be used to form the three-dimensional patterns on the first layer whereby the three-dimensional patterns are made completely of HA with different layer of HA with different molecular weights. In one embodiment, the HA can be cast on a cellulose first layer which is porous. In use, when such a mask is pressed against the surface of a face, the HA can provide the exfoliation and open up the surface pores while the active ingredient(s) from the second layer elutes through the first layer, the HA dissolves within the skin and thereby becomes absorbed by the skin. In a similar manner, any material that is able to dissolve can be used to form the three-dimensional patterns, or a mixture of dissolving materials can be used to form the three-dimensional patterns.
The hydrogel may be woven or non-woven. The hydrogel may be gelatin methacryloyl (GelMA) hydrogel. The GelMA hydrogel may be mixed with a suitable photoinitiator such as Irgacure 2959 or lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) prior to light-induced polymerization.
Stratum corneum, as the outermost layer of the epidermis, is a rate-limiting barrier for facial skin absorption. The three-dimensional patterns may be used to provide mechanical exfoliation, whereby the physical structure and shape of the three-dimensional patterns influence the mechanical exfoliation effect. The three-dimensional pattern may comprise an exfoliating agent to provide chemical exfoliation. Both mechanical exfoliation and chemical exfoliation may be provided simultaneously by the three-dimensional patterns to facial skin. Thus, the three-dimensional patterns may physically remove dead skin cells in the stratum corneum by mechanical and/or chemical exfoliation, thus increasing the rate of facial skin absorption of active ingredient(s). Advantageously, the exfoliation action of the three-dimensional patterns may improve the appearance of uneven skin tone and bring radiance to a dull complexion.
The three-dimensional patterns may comprise an exfoliating agent selected from the group consisting of alpha hydroxy acids, beta hydroxy acids, plant-based enzymes, animal-based enzymes and mixtures thereof; or wherein the three-dimensional patterns may comprise an exfoliating agent selected from the group consisting of lactic acid, last obionic acid, glycolic acid, hydroxycaproic acid, hydroxycaprylic acid, citric acid, malic acid, mandelic acid, tartaric acid, phytic acid, salicylic acid, hyaluronic acid, azelaic acid, kojic acid, ascorbic acid, trichloroacetic acid, alguronic acid, lipoic acid, ferulic acid and mixtures thereof.
Lactic acid may provide many of the same benefits as other alpha hydroxyl acids but may be safe for use on sensitive skin since lactic acid works by breaking down and dissolving dead skin cells without causing irritation through a long period of application, depending on the molecular weight of the lactic acid. The lactic acid to be incorporated in the porous first layer of the multi-layered sheet mask may be obtained by degradation of poly(lactic acid) of molecular weight 5000 g/mol into degradation products of less than about 100 g/mol. The degradation of poly(lactic acid) may be via a biodegradation process.
Further, lactic acid to be incorporated in the porous first layer may prevent facial skin from dehydration and keep the skin moisturized. As molecules of different molecular weights may penetrate to different depths of the skin, molecules with a lower molecular weight may reach deeper layer(s) of skin, thus sustaining the moisture content of the skin at deeper layer(s). Further, lactic acid to be incorporated in the porous first layer may reduce the signs of ageing by improving the appearance of fine lines. In addition, lactic acid may increase facial skin firmness and thickness. Thus, the primary benefits of lactic acid for skin may include: 1) brightening and evening skin tone, 2) stimulating skin cell turnover and renewal; 3) revealing glowing facial surfaces and 4) anti-ageing effect to result in youthful looking skin.
For hyaluronic acid, the average molecular weight may be in a range of about 1,000,000 g/mol to about 8,000,000 g/mol, about 1,000,000 g/mol to about 6,000,000 g/mol, about 1,000,000 g/mol to about 5,000,000 g/mol, about 1,000,000 g/mol to about 4,000,000 g/mol, about 1,000,000 g/mol to about 2,000,000 g/mol, about 2,000,000 g/mol to about 8,000,000 g/mol, about 2,000,000 g/mol to about 6,000,000 g/mol, about 2,000,000 g/mol to about 5,000,000 g/mol, about 2,000,000 g/mol to about 4,000,000 g/mol, about 4,000,000 g/mol to about 8,000,000 g/mol, about 4,000,000 g/mol to about 6,000,000 g/mol, about 4,000,000 g/mol to about 5,000,000 g/mol, about 5,000,000 g/mol to about 8,000,000 g/mol, about 5,000,000 g/mol to about 6,000,000 g/mol, or about 6,000,000 g/mol to about 8,000,000 g/mol.
The three-dimensional patterns may have an average diameter in the range of about 1 μm to about 1 mm, about 10 μm to about 1 mm, about 50 μm to about 1 mm, about 100 μm to about 1 mm, about 500 μm to about 1 mm, about 1 μm to about 10 μm, about 1 μm to about 50 μm, about 1 μm to about 100 μm, about 1 μm to about 500 μm, about 10 μm to about 50 μm, about 10 μm to about 100 μm, about 10 μm to about 500 μm, about 50 μm to about 100 μm, about 50 μm to about 500 μm, or about 100 μm to about 500 μm.
The three-dimensional patterns may have a height in the range of about 1 mm to about 3 mm, about 1.2 mm to about 3 mm, about 1.5 mm to about 3 mm, about 2 mm to about 3 mm, about 2.5 mm to about 3 mm, about 1 mm to about 1.2 mm, about 1 mm to about 1.5 mm, about 1 mm to about 2 mm, about 1 mm to about 2.5 mm, about 1.2 mm to about 1.5 mm, about 1.2 mm to about 2 mm, about 1.2 mm to about 2.5 mm, about 1.5 mm to about 2 mm, about 1.5 mm to about 2.5 mm, or about 2 mm to about 2.5 mm.
In general, the stratum corneum has a thickness between 10 μm and 40 μm. For the three-dimensional patterns that only conduct mechanical exfoliation, the height of the three-dimensional patterns may be designed to penetrate the stratum corneum but not penetrate to the dermis layer of the facial skin. Therefore, the dead skin cells in stratum corneum may be removed by the three-dimensional patterns without hurting the dermis layer.
The three-dimensional patterns may have a height designed based on a typical topographic thickness of the stratum corneum of the facial skin to achieve a homogenous penetration depth in different zones of the facial skin to maximize exfoliation. Thus, the height of the three-dimensional patterns may be different for different zones of the facial skin.
The three-dimensional patterns may comprise a plurality of pointed three-dimensional shapes as skin-engaging ends, wherein the pointed three-dimensional shapes may be selected from the group consisting of cone, pyramid, stellated polyhedron, regular polyhedron, irregular polyhedron partial regular polyhedron, partial irregular polyhedron, sphere and at least one cone, sphere and at least one spike, sphere and at least one pyramid, hemisphere and at least one spike, spike, and combinations thereof.
The pointed three-dimensional shapes may comprise the exfoliating agent.
The pointed three-dimensional shapes may have a height in the range of about 200 μm to about 250 μm, about 210 μm to about 250 μm, about 220 μm to about 250 μm, about 230 μm to about 250 μm, about 240 μm to about 250 μm, about 200 μm to about 210 μm, about 200 μm to about 220 μm, about 200 μm to about 230 μm, about 200 μm to about 240 μm, about 210 μm to about 220 μm, about 210 μm to about 230 μm, about 210 μm to about 240 μm, about 220 μm to about 230 μm, about 220 μm to about 240 μm, or about 230 μm to about 240 μm.
When the pointed three-dimensional shapes comprise of at least one spike, each spike may have a length in the range of about 40 μm to about 100 μm, about 50 μm to about 100 μm, about 60 μm to about 100 μm, about 80 μm to about 100 μm, about 40 μm to about 50 μm, about 40 μm to about 60 μm, about 40 μm to about 80 μm, about 50 μm to about 60 μm, about 50 μm to about 80 μm, or about 60 μm to about 80 μm.
The spike may be further positioned at an angle in the range of about 10° to about 30°, about 15° to about 30°, about 20° to about 30°, about 25° to about 30°, about 10° to about 15°, about 10° to about 20°, about 10° to about 25°, about 15° to about 20°, about 15° to about 25°, or about 20° to about 25° from the vertical plane.
When the spike is positioned at an angle from the vertical plane, the spike may have higher penetration area from the angle and from an adjacent area of a center spike, as compared to a spike that is not positioned at an angle from the vertical plane.
Further, when the spike is positioned at an angle from the vertical plane, the spike may have a different depth of penetration when the first layer of the multi-layered sheet mask is compressed, as compared to a spike that is not positioned at an angle from the vertical plane.
The slits of the porous first layer may extend from the second side of the porous first layer to the first side of the porous first layer. The slits of the porous support structure of the second layer may extend from one side to another side of the porous support structure.
The slits of the porous first layer and slits of the porous support structure of the second layer may have an inner diameter in the range of about 1 μm to about 100 μm, about 10 μm to about 100 μm, about 20 μm to about 100 μm, about 50 μm to about 100 μm, about 80 μm to about 100 μm, about 10 μm to about 20 μm, about 10 μm to about 50 μm, about 10 μm to about 80 μm, about 20 μm to about 50 μm, about 20 μm to about 80 μm, or about 50 μm to about 80 μm.
The slits of the porous first layer and slits of the porous support structure of the second layer may have an outer diameter in the range of about 100 μm to about 150 μm, about 110 μm to about 150 μm, about 120 μm to about 150 μm, about 130 μm to about 150 μm, about 140 μm to about 150 μm, about 100 μm to about 110 μm, about 100 μm to about 120 μm, about 100 μm to about 130 μm, about 100 μm to about 140 μm, about 110 μm to about 120 μm, about 110 μm to about 130 μm, about 110 μm to about 140 μm, about 120 μm to about 130 μm, about 120 μm to about 140 μm, or about 130 μm to about 140 μm.
The slits of the porous first layer and slits of the porous support structure of the second layer may function as paths to allow the active ingredient(s) to flow to the facial skin. When the at least one pouch in the second layer is punctured by the plurality of microchannels when the air pouch is deflated, the slits of the porous support structure of the second layer may help direct the at least one first active ingredient from the at least one pouch to the porous first layer The at least one first active ingredient may be further directed by the slits of the porous first layer to the surface of the skin for skin absorption.
The slits of the porous first layer and slits of the porous support structure of the second layer may have different shapes to control the flow rate of active ingredient(s) passing through the slits. Thus, the active ingredient(s) may flow through the slits of the porous first layer and slits of the porous support structure of the second layer at a controlled flow rate and be delivered to the recipient of the multi-layered sheet mask.
The flow rate of the active ingredient(s) through the slits of the porous first layer and slits of the porous support structure of the second layer may be in a range of about 0.1 ml/min to about 100 ml/min, about 1 ml/min to about 100 ml/min, about 10 ml/min to about 100 ml/min, about 20 ml/min to about 100 ml/min, about 50 ml/min to about 100 ml/min, about ml/min to about 100 ml/min, about 0.1 ml/min to about 1 ml/min, about 0.1 ml/min to about 10 ml/min, about 0.1 ml/min to about 20 ml/min, about 0.1 ml/min to about 50 ml/min, about 0.1 ml/min to about 80 ml/min, about 1 ml/min to about 10 ml/min, about 1 ml/min to about 20 ml/min, about 1 ml/min to about 50 ml/min, about 1 ml/min to about 80 ml/min, about 10 ml/min to about 20 ml/min, about 10 ml/min to about 50 ml/min, about 10 ml/min to about 80 ml/min, about 20 ml/min to about 50 ml/min, about 20 ml/min to about 80 ml/min, or about 50 ml/min to about 80 ml/min.
The slits of the porous first layer and slits of the porous support structure of the second layer may have a shape selected from the group consisting of polyhedron, non-polyhedron, and combinations thereof; or wherein the slits of the porous first layer and slits of the porous support structure of the second layer may have a shape selected from the group consisting of cylinder, prism, and combinations thereof; or wherein the slits of the porous first layer and slits of the porous support structure of the second layer may have a hexagonal prism shape. Collectively, an area of the slits of the porous first layer and an area of the slits of the porous support structure of the second layer may be viewed as a honeycomb structure.
The microchannels may penetrate through the three-dimensional patterns if the three-dimensional patterns are designed to have a hollow center for microchannels to penetrate through. In this instance, the three-dimensional patterns may provide exfoliation and insert first active ingredient to the dermis layer of the facial skin, wherein the microchannels may have one end inserted in the pouch in the second layer and have the other end penetrate the dermis layer of the skin when the air pouch is deflated. Otherwise, the three-dimensional patterns without microchannels penetrating through are non-hollow three-dimensional patterns for conducting exfoliation, such that on the facial skin, the microchannel may be adjacent to the non-hollow three-dimensional patterns for near-site dispensing of first active ingredient.
The microchannels may comprise pointed tips which penetrate the second side of the porous first layer, the first side of the porous first layer, an epidermis layer of a skin, and a dermis layer of a skin, when the air pouch is deflated.
The microchannels may have a height designed based on a typical topographic thickness of the human facial skin to achieve a homogenous penetration depth in different zones of the facial skin, when the mask to used on a human. Thus, the height of the microchannels may be different for different zones of the facial skin. This may enable the first and/or second active ingredients to be delivered to a similar depth in different zones of the facial skin, allowing the skin cells to receive the active ingredient(s) evenly.
The microchannels of the second layer of the mask may have a height corresponding to different zones of a face as follows:
The microchannels may further comprise a plurality of pointed branches thereon. The pointed branches may puncture the air pouch to release the air encapsulated and may puncture the pouch to release the at least one active ingredient, when the multi-layered sheet mask is pressed.
Facial skin cells may be dehydrated, especially when the stratum corneum is thinned. The second layer of the multi-layered sheet mask may be used to address the issue of dehydrated facial skin by provision of the at least one first active ingredient. When the skin cells are hydrated by the at least one first active ingredient, the water content within the cells may cause the cells to swell, thus causing the skin to appear bouncy and reflects light well.
The at least one first active ingredient in each of the at least one pouch of the second layer may be the same or different from each other.
The first active ingredient may be selected from the group consisting of anti-pigmentation agent, anti-ageing agent, anti-wrinkle agent, anti-acne agent, moisturizing agent, treatment agent, and mixtures thereof.
The at least one first active ingredient may further comprise a fragrance.
The at least one pouch in the second layer of the multi-layered sheet mask may have a volume in a range of about 1 ml to about 5 ml, about 2 ml to about 5 ml, about 3 ml to about 5 ml, about 4 ml to about 5 ml, about 1 ml to about 2 ml, about 1 ml to about 3 ml, about 1 ml to about 4 ml, about 2 ml to about 3 ml, about 2 ml to about 4 ml, or about 3 ml to about 4 ml.
Other active ingredients for enhancing the aesthetics of facial skin may be provided by the third layer of the multi-layered sheet mask by provision of the at least one second active ingredient. Where different active ingredients are used, this may provide more benefits to the recipient.
The third layer may be portioned into a number of parts, each part receiving or containing the at least one second active ingredient that may be the same or different from each other; and
The at least one second active ingredient may further comprise a fragrance.
The at least one second active ingredient in the third layer of the multi-layered sheet mask may have a volume in a range of about 1 ml to about 5 ml, about 2 ml to about 5 ml, about 3 ml to about 5 ml, about 4 ml to about 5 ml, about 1 ml to about 2 ml, about 1 ml to about 3 ml, about 1 ml to about 4 ml, about 2 ml to about 3 ml, about 2 ml to about 4 ml, or about 3 ml to about 4 ml.
The anti-pigmentation agent may be selected from the group consisting of N-acetyl glucosamine, hydroquinone, kojic acid, arbutin, resveratrol, tranexamic acid, niacinamide, liquorice extract, azelaic acid, and mixtures thereof.
The anti-ageing agent may be selected from the group consisting of azelaic acid, retinoic acid, retinol, hyaluronic acid, ascorbic acid, vitamin E, allantoin, bisabolol, and mixtures thereof.
The anti-acne agent may be selected from the group consisting of retinoic acid, retinol, topical antibiotics, tea tree oil, usnic acid, gluconolactone, Cannabis sativus, and mixtures thereof.
The moisturizing agent may be selected from the group consisting of water, carbomer, humectants, glycerin, hydroxyethylurea, acetamidoethoxyethanol betaine, inositol, taurine, emollients, isopropyl isostearate, isostearyl isostearate, C12-13 alkyl lactate, ceramide, pseudo-ceramide, cetyl PG hydroxyethyl palmitamide, ceramide II complex, niacinamide, Eucalyptus globulus leaf extract, cetearyl glucoside, PEG-100 stearate, distearyl dimethyl ammonium chloride, ceteareth 20, PEG-40 stearate, cetearyl alcohol, stearyl alcohol, cetyl alcohol, glyceryl stearate, xanthan gum, carbomer, acrylates/C10-30 alkyl acrylate crosspolymer, phenoxyethanol, benzyl alcohol, benzalkonium chloride, ethylhexyl glycerin, caprylyl glycol, hexanediol, pentylene glycol, glutamic acid, N.N-diacetic acid, sodium phytate, tetrasodium iminodisuccinate, and mixtures thereof. The C12-13 alkyl lactate may stimulate epidermal lipids production and provide skin hydration. The Eucalyptus globulus leaf extract may promote epidermal lipids production and sensitize the skin.
The treatment agent may be selected from the group consisting of ceramide, collagen, antioxidant, anti-inflammatory, and mixtures thereof.
The oil may be selected from the group consisting of coconut oil, olive oil, sunflower seed oil, shea butter oil, jojoba oil, almond oil, grapeseed oil, blackcurrent seed oil, chamomile oil, rosehip seed oil, argan oil, marula oil, tea tree oil, safflower seed oil, cedarwood oil, vetiver oil, neroli oil, helichrysum oil, facial oil, essential oil, vitamin E oil, and mixtures thereof.
The oil may have UV-screening function.
The oil may provide skin with moisture by locking in hydration, especially after a moisturizing agent is used in the at least one first active ingredient.
The chemical sunscreen may be selected from the group consisting of oxybenzone, avobenzone, octisalate, octocrylene, hornosalate, octinoxate, and mixtures thereof.
The air pouch in the second layer of the multi-layered sheet mask may lift the plurality of microchannels when the air pouch is inflated.
The height of the air pouch may be in a range of about 400 μm to about 500 μm, about 420 μm to about 500 μm, about 440 μm to about 500 μm, about 460 μm to about 500 μm, about 480 μm to about 500 μm, about 400 μm to about 420 μm, about 400 μm to about 440 μm, about 400 μm to about 460 μm, about 400 μm to about 480 μm, about 420 μm to about 440 μm, about 420 μm to about 460 μm, about 420 μm to about 480 μm, about 440 μm to about 460 μm, about 440 μm to about 480 μm, or about 460 μm to about 480 μm.
When the porous first layer of the multi-layered sheet mask is being applied for exfoliation, the microchannels may not penetrate the skin until the air pouch is fully deflated. Hence, the air pouch may provide cushion for the first and second layers of the multi-layered sheet mask from microchannels penetration. Air inside the air pouch may be released through a twist-and-turn valve to allow the microchannels to penetrate the skin. Advantageously, the twist-and-turn valve may avoid accidental puncturing of the air pouch when some force is applied on the multi-layered sheet mask, for instance during the exfoliation process when the porous first layer of the multi-layered sheet mask is in use.
The size of the air pouch is not limited and may vary depending on the therapeutic application of the multi-layered sheet mask.
The air pouch may be made from high molecular-weight polymer such as poly(lactic-co-glycolic acid) (PLGA), poly(L-lactic acid) (PLLA) or polyvinyl chloride (PVC). The high molecular weight polymer may be biodegradable or non-biodegradable.
The molecular weight of the high molecular weight polymer may be in the range of about g/mol to about 1,000,000 g/mol, about 100,000 g/mol to about 1,000,000 g/mol, about 200,000 g/mol to about 1,000,000 g/mol, about 500,000 g/mol to about 1,000,000 g/mol, about 800,000 g/mol to about 1,000,000 g/mol, about 80,000 g/mol to about 100,000 g/mol, about 80,000 g/mol to about 200,000 g/mol, about 80,000 g/mol to about 500,000 g/mol, about g/mol to about 800,000 g/mol, about 100,000 g/mol to about 200,000 g/mol, about 100,000 g/mol to about 500,000 g/mol, about 100,000 g/mol to about 800,000 g/mol, about 200,000 g/mol to about 500,000 g/mol, about 200,000 g/mol to about 800,000 g/mol, or about 500,000 g/mol to about 800,000 g/mol.
A circumferential edge comprising the circumferential edges of the porous first layer, the second layer, and the third layer, may have a width of at least about 5 mm.
A detachable fourth layer may also be incorporated into the multi-layered mask for final cleaning of the facial skin.
Exemplary, non-limiting embodiments of a mould for producing the three-dimensional patterns of the porous first layer of the multi-layered sheet mask will now be disclosed. The mould for producing the three-dimensional patterns of the porous first layer of the multi-layered sheet mask as disclosed herein comprises a negative replica of the three-dimensional patterns.
Advantageously, the mould may be designed to comprise a negative replica of the three-dimensional patterns of the porous first layer of the multi-layered sheet mask, which is dedicated for specific zones of the facial skin based on skin thickness and/or skin condition.
Further advantageously, the mould may allow the facile reproduction of complex micrometre-scale three-dimensional structures as exfoliators for cosmetic purposes.
When the polymer solution or melt forms the three-dimensional patterns in the mould, a sheet mask mould may be used to press the material forming the first layer onto the three-dimensional pattern mould. In this way, when the first layer material is removed from the three-dimensional pattern mould, the three-dimensional patterns will be formed (or stuck onto) the first later. Therefore, another mould such as a sheet mask mould can also be used.
The mould may further comprise a plurality of holes in sub-micrometre scale within the negative replica. The size range of these holes may be about 100 μm to about 1 mm.
The plurality of holes may allow negative pressure or air suctions to be applied on the mould during the process of casting when the polymer solution or melt is overlaid onto the mould, such that the polymer solution or melt may completely fill the contours of the mould.
The mould may be transparent. This may allow UV radiation to pass through from all sides of the mould to induce curing of the UV-curable polymer solution or melt that is overlaid onto the mould.
The mould may be formed by polymerizing a resin over a printed mould comprising a positive replica of the three-dimensional patterns. The printed mould may be a 3D-printed mould.
The mould may be formed in an inert gas environment (e.g., nitrogen gas or argon gas) with constant negative pressure applied, to avoid inhibition by the presence of oxygen during the polymerization process.
Exemplary, non-limiting embodiments of a method of producing a multi-layered sheet mask will now be disclosed.
The method of producing a multi-layered sheet mask comprises the steps of:
Advantageously, the method may result in a porous first layer of multi-layered sheet mask which offers both mechanical and chemical exfoliation via the three-dimensional patters for effective removal of dead skin cells.
Further advantageously, the method may be adaptable to create additional layers, for example the fourth or fifth layers of mask, to offer additional cosmetic treatment for the facial skin. The method may also be adaptable to create multi-layered sheet mask for other parts of the body besides the face.
The three-dimensional patterns of step (a) may be formed by filling sections of the whole facial mask mould with the material of step (a) and vacuuming for a duration; and wherein the sections comprise of the mould as disclosed herein.
The sections may correspond to facial areas selected from the group consisting of hairline, forehead, temple, nose, cutaneous upper lip, philtum, philtum crest, cutaneous lower lip, chin, cheeks, midface, jawline, and combinations thereof.
The attaching of steps (b) and (b) may be done by heat bonding.
The attaching of step (b) may further comprise the step of applying fastening strips between the first and second layers; or wherein the attaching of step (c) may further comprise the step of applying fastening strips between the second and third layers.
The fastening strips may be Velcro strips, hooks or loops.
The use of heat bonding and/or Velcro strips may be safer and cost-efficient as compared to the use of adhesives.
The bonding of steps (b) and (c) may be for at least a width of about 5 mm of the circumferential edges. A broader width used may reduce the functional area of the multi-layered sheet mask, while a narrower width below about 5 mm may not result in stable attachment of the layers of the multi-layered sheet mask.
The porous first layer and the porous support structure of the second layer may comprise a plurality of slits. The method may thus further comprise the step of (d) forming slits in the porous first layer and the porous support structure. The forming step (d) may comprise the step of stamp cutting slits into the first layer or support structure. Alternatively, the forming step (d) may comprise the step of forming pores into the first layer or support structure that then form the slits.
The accompanying drawings illustrate a disclosed embodiment and serve to explain the principles of the disclosed embodiment. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention.
Non-limiting examples of the invention will be further described in greater details by reference to specific Examples, which should not be construed as in any way limiting the scope of the invention.
Models of the 3D-printed moulds comprising positive replicas of the desired three-dimensional patterns were designed using SolidWorks (Dassult Systèmes, USA) to have various pointed three-dimensional shapes and synthesized by 3D printing using a Titan 2HR 3D printer (Kudo 3D, USA) with Optoma Projector with light spectrum >=400 nm (visible range) as the light source, light intensity set at 3000 lumens, slicing software from Creation workshop, resin (3DM cast from ADMAT of France), layer splicing at 25 μm, pixel resolution at 26 μm and exposure time set at 6 to 16 seconds.
With reference to
Polydimethylsiloxane (PDMS) is a two-part polymer (Base Elastomer and Curing Agent). Here, Sylgard 184 from Dow Corning was used. The standard mixing ratio for PDMS is 10-parts base elastomer and 1-part curing agent. This ratio provides the mechanical properties that are desirable and optimum biocompatibility. The solution material (or precursor solution) for three-dimensional pattern can be any biocompatible material but in this example, hyaluronic acid was used as the solution material (or precursor solution).
Firstly, to prepare the polymeric solution, the base elastomer and curing agent of the PDMS were mixed at a ratio recommended by the manufacturer which is a base to curing agent ratio of 10:1 (by parts) and de-aired for 30 minutes by applying negative pressure of −95 kPa. The polymeric solution was poured onto the cured 3D-printed mould in a container and vacuumed at −95 kPa for 30 minutes to ensure that bubbles were removed completely. The container containing the polymeric solution was cured at 80° C. for 30 minutes. After the polymeric solution was completely cured, the 3D-printed mould was removed from the cured polymeric mould by applying a force to detach the 3D-printed mould from the cured polymeric mould (which is a polydimethylsiloxane mold). This is a pre-casting step to create two halves of the negative replica of the 3D-printed mold.
Thereafter, hyaluronic acid (4 g of HA in 20 ml DI water for 20% stock HA solution) was filled into the microneedles of the polymeric PDMS mould and the whole 3D printed PLA mask mold was put under vacuum at 95 kPa for 30 minutes. The cellulose mask sheet was placed on top of the PLA mould with PDMS negative needles filled with hyaluronic in the PDMS mould and ensuring the cellulose sheet is in contact with the hyaluronic acid three-dimensional patterns. A weight was placed and secured with stainless steel rods to ensure good contact between the mask and the filled casted HA solution in the PDMS mould. The cellulose mask with filled HA solution was left dried at room conditions for at least 48 hours. After the HA solution was completely dried out, the cellulose mask with the HA three0dimensional patterns was removed from the mould, thus forming the first layer of the multi-layered sheet mask.
The following materials were purchased commercially for use in this example without modification: hyaluronic acid molecular weight 8 to 15 kDa (MakingCosmetics, USA), Sylgard 184 silicon elastomer kit (Dow Corning, USA), polylactic acid (PLA, Makerbot Industries, USA), 3DM-CAST resin (ADMAT, France) and mask-shaped cellulose (under brand name BIO-Celtox™ obtained from Guangzhou Yurui Cosmetics Co., Ltd, China) and isopropyl alcohol. De-ionised water was used.
Titan 2HR 3D printer (Kudo 3D, USA) was used to print the 3D-printed mould of the three-dimensional patterns. The three-dimensional patterns may be specific to a certain zone on the facial skin, as shown in
The 3D-printed mould was washed two times at 15 minutes per wash using isopropyl alcohol. Thereafter, the 3D-printed mould was air-dried at room temperature followed by post-curing under UV irradiation for 30 minutes. Multiple 3D-printed moulds may be synthesized for different zones of facial skin. Examples of the 3D-printed moulds of three-dimensional patterns are shown in
A schematic diagram illustrating this process is shown in
MakerBot Replicator Z18 (Makerbot Industries, USA) and biodegradable polylactic acid (PLA, Makerbot Industries, USA) were used to make the prototype whole facial mask mould. A model of the whole facial mask mould was designed using SolidWorks (Dassult Systèmes, USA) according to the printing parameters settings shown in Table 2. The whole facial mask mould was designed with hollow portions on the forehead, under eyelids, cheeks, nose, smile lines, upper lip lines and chin as shown in
A schematic diagram illustrating the process to prepare a whole facial mask which forms the porous first layer of a multi-layered sheet mask, where the three-dimensional patterns comprise an exfoliating agent is shown in
The following materials were purchased commercially for use in this example without modification: lidocaine, diclofenac sodium, acetonitrile HPLC grade (Merck, USA), ethanol, ammonium formate (Merck, USA), phosphate buffered saline (PBS, Vivantis, Singapore). Water used was purified by Mili-Q system. Human cadaver dermatone skin used for the analysis was obtained from Science Care (Phoenix, AZ, USA). The experiment was conducted using vertical Franz diffusion cells at 32° C. with an effective exposed area of 1 cm2. The skin piece used in this experiment had a thickness of 150 μm to 200 μm and area of 2×2 cm.
An active ingredient composition used in this experiment comprised 23% lidocaine and 1% diclofenac sodium in the form of a cream. 5 mL of phosphate buffered saline (PBS) in the receptor compartment was used as the medium for absorption of the active ingredient composition. The test was conducted by applying patches containing three-dimensional patterns according to designs of
Based on the results in
The multi-layered sheet mask as disclosed herein may be used as a skincare product or a skin treatment product for providing a variety of cosmetic enhancements for facial skin, such as pigmentation alleviation, anti-wrinkle, anti-ageing, anti-acne, collagen growth stimulation and hydration. The multi-layered sheet mask may also be applied to other skin areas on the body besides facial skin.
The mould as disclosed herein may be used in the cosmetics, personal care and biomedical industries to produce complex three-dimensional patterns for enhanced skin engagement. The method as disclosed herein may be used in the cosmetics, personal care and biomedical industries to produce multi-layered structures that combine different functionalities of each layer into a single structure, with enhanced delivery of active ingredients into skin.
It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention and it is intended that all such modifications and adaptations come within the scope of the appended claims.
This application claims priority to U.S. provisional application No. 63/198,726 filed on 9 Nov. 2020, the disclosure of which is hereby incorporated by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/SG2021/050685 | 11/9/2021 | WO |
Number | Date | Country | |
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63198726 | Nov 2020 | US |