A set containing a shower or bath hygiene product wrapped in a functional water-soluble film

Abstract

The present invention relates to an assembly comprising a shower or bath hygiene product (1) and a film (2), in which said shower or bath hygiene product (1) is wrapped in said film (2), characterized in that said film (2) is water-soluble, and in that said film (2) comprises at least: a main component consisting of sodium alginate, the weight content of which in said film is greater than or equal to 25%, and a surfactant. The present invention also relates to a use of an assembly according to the invention. Abstract figure: Figure 1

Description

Title of the invention: assembly comprising a shower or bath hygiene product wrapped in a functional water-soluble film

[0001] The present invention relates to the field of shower or bath hygiene products. More particularly, it concerns a shower or bath hygiene product wrapped in a water-soluble film capable of giving it foaming and emulsifying properties.

[0002] Shower and bath hygiene products are usually sold in plastic containers. These plastic containers are harmful to the environment, and are heavy to transport and bulky at home.

[0003] Document WO2018 proposes a film for packaging shampoo. This reduces the volume of plastic containers, but is not practical.

[0004] An object of the present invention is to offer a shower hygiene product whose packaging is made from biodegradable products that are not harmful to the environment.

[0005] Another object of the present invention is to provide lightweight packaging for shower or bath hygiene products.

[0006] Another object of the present invention is to provide packaging for shower or bath hygiene products which provides foaming and emulsifying functions to the shower or bath hygiene product.

[0007] Another object of the present invention is to provide packaging for shower or bath hygiene products which provides a moisturizing function to the shower or bath hygiene product.

[0008] The present invention aims to address, at least in part, the aforementioned objectives by providing an assembly comprising a water-soluble film containing a surfactant capable of imparting foaming and emulsifying properties to a hygiene product. To this end, it provides an assembly comprising a shower or bath hygiene product and a film, in which said shower or bath hygiene product is enclosed within said film, characterized in that said film is water-soluble, and in that said film comprises at least:

[0009] - a main component consisting of sodium alginate, the weight content of which in said film is greater than or equal to 25%, and - a surfactant.

[0010] Thanks to these provisions, the shower or bath hygiene product is wrapped in a lightweight, water-soluble film that can be entirely bio-based and biodegradable, and therefore not harmful to the environment. Furthermore, upon its dissolution in Water, the surfactant of the film can mix with the shower or bath hygiene product and give it emulsifying and / or foaming properties.

[0011] According to other characteristics:

[0012] - the weight content of said surfactant in said film can be between 1 and 30%, which allows the film to impart a good level of emulsifying and foaming properties to the hygiene and shower product, - The surfactant can be of natural origin, of the non-ionic or anionic type, which allows the film to be biodegradable and less harmful to the human body, - The dynamic viscosity of sodium alginate, the main component of the film, can be between 200 and 500 mPa s, which contributes to the film having good mechanical properties of strength and flexibility. - said film may further comprise glycerol, the content of which by weight in said film may be between 10 and 35%, enabling it to act as a plasticizer to obtain a thin, resistant and flexible film, - said film may further comprise a crosslinking agent such as magnesium chloride, the weight content of which in said film may be between 3 and 5%, which further improves the mechanical strength of the film, the magnesium chloride allowing the film to maintain good solubility in water, - said film may further comprise a thickening agent, the weight content of which in said film may be between 1 and 30%, which imparts moisturizing properties to the bath or shower hygiene product upon dissolution of the film, - the thickening agent can be a sodium alginate with a dynamic viscosity between 3000 and 6000 mPa s, which is a simple and effective embodiment of the invention,

[0013] The present invention also relates to a use of an assembly according to the invention, in which said film is dissolved on contact with water, releasing said surfactant from said film, said surfactant providing emulsifying and / or foaming properties to said shower or bath hygiene product by mixing with it.

[0014] Thanks to these provisions, the shower or bath hygiene product is wrapped in a lightweight, water-soluble film that can be entirely bio-based and biodegradable, and therefore not harmful to the environment. Furthermore, when dissolved in water, the surfactant in the film can mix with the shower or bath hygiene product, giving it emulsifying and foaming properties.

[0015] According to other characteristics:

[0016] - the dissolution of the film can release a thickening agent contained in the film, which provides moisturizing properties to said shower or bath hygiene product by mixing with it, which makes it possible to have a film within the framework of the present invention capable of providing moisturizing properties to a shower or bath hygiene product.

[0017] The present invention will be better understood upon reading the following detailed description, with reference to the accompanying figures in which:

[0018] [Fig-1] Fig. 1 is a schematic view of an assembly according to a mode of realization preferred interpretation of the invention.

[0019] [Fig.2] Fig.2 is a microscopic view of micelles during the execution of the second test,

[0020] [Fig.3] The [Fig.3] is a cross-sectional view of the contact angle between a water droplet and the skin of a user.

[0021] The assembly according to the invention, illustrated in [Fig.1], comprises a shower or bath hygiene product 1 and a film 2, the shower or bath hygiene product 1 being wrapped in the film 2.

[0022] In the context of the present invention, the term shower or bath hygiene product refers to any liquid or solid personal hygiene product intended for use in the shower or bath. It includes, for example, soap, shower gel, shower oil, shampoo, conditioner, pre-shampoo treatment, or hair detangler.

[0023] Film 2 is soluble in water. The solubility of a film in water can be measured as follows: a piece of film (5 cm x 5 cm, cut with a punch) is fixed to a slide holder and then immersed in a 1000 ml beaker containing 600 ml of distilled water at 20°C, while being stirred with a magnetic stir bar at 300 rpm. The time it takes for the film to break through is measured. The disintegration of the film results in the formation of film particles. The test lasts 5 minutes, after which the particles are passed through a 0.5 mm sieve to check their size. When no particles are found on the sieve, the film is considered water-soluble.

[0024] In the context of the present invention, it is considered in particular that the film dissolves in a few minutes, for example in less than 3 minutes, when it comes into contact with water at bath or shower temperature. This temperature can be between 15 and 40°C, for example 37°C for a hot bath, or for example 18°C ​​for a cold shower.

[0025] Film 2 comprises a main component consisting of sodium alginate. The weight content of the main component in film 2 is greater than or equal to 25%, preferably between 30 and 50%. The sodium alginate of the main component It preferably has a dynamic viscosity between 200 and 500 mPa s, which allows for a flexible and resistant film. For example, it could be "Vivapharm" (registered trademark) Alginate PH R5 or equivalent.

[0026] In the context of this application, the dynamic viscosity values ​​correspond to the values ​​measured by the Brookfield method.

[0027] Film 2 also includes a surfactant.

[0028] The surfactant may be of the non-ionic type. It is then for example a polyoxyethylene, an alkanolamide, a glucoside or an oligopeptide, for example an ethoxylated alkylphenol, an ethoxylated alcohol, a decyl glucoside, a cetyl alcohol, a glutamate, a lauryl glucoside, or a coco glucoside.

[0029] The surfactant may also be anionic such as a salt of carboxylic acid, lipoamino acids, lipo-oligopeptides, a sulfonated derivative or a sulfated derivative, for example sodium lauryl sulfate (SLS), ammonium lauryl sulfate (ALS) or one of its ethoxylated derivatives, sodium laureth sulfate (SLES), or a sulfonic acid surfactant such as a taurate, an isethionate, an olefin sulfonate, or a sulfosuccinate.

[0030] The surfactant may also be of the cationic type, for example an amine, an alky-limidazoline, an alkoxylated amine, a behentrimonium methosulfate (BTMS), or a quaternary ammonium compound (also called Quats).

[0031] The surfactant may be of the amphoteric type, such as a betaine, or an amino acid or imidazole derivative, for example cocamidopropyl betaine.

[0032] The weight content of the surfactant in the film 2 is preferably between 1 and 30%, preferably between 5 and 25%.

[0033] The presence of the surfactant in film 2 allows the shower or bath product 1 to develop foaming and emulsifying properties when film 2 dissolves upon contact with water. The foam facilitates the distribution of the shower or bath product 1 on the skin and prevents excessive friction on the body or scalp. The emulsifying properties, in turn, provide the shower or bath product 1 with a more effective cleansing action.

[0034] A naturally derived surfactant, such as a non-ionic agent from the glucoside family, like coco-glucoside, or an anionic agent such as sodium cocoyl glutamate, has the advantage of being gentler and more natural than the synthetic surfactants commonly used in shower or bath hygiene products. Furthermore, the main component is not harmful to the skin or the environment.

[0035] The assembly according to the invention can be used in the following manner: the film 2 dissolves upon contact with water at a temperature greater than or equal to 20°C, releasing the surfactant. The surfactant then imparts emulsifying and / or foaming properties to the shower or bath hygiene product 1 by mixing with it. here.

[0036] Film 2 may further comprise a thickening agent, the weight content of which in film 2 is, for example, between 1 and 30%. This thickener is, for example, a sodium alginate with a dynamic viscosity greater than 2500 mPa s, preferably between 3000 and 6000 mPa s. It may, for example, be "Vivastar" (registered trademark) CS 052 Alginate or equivalent.

[0037] The presence in film 2 of the thickening agent allows, when film 2 dissolves on contact with water, to give the shower or bath hygiene product 1 moisturizing properties by mixing with it.

[0038] The film 2 preferably comprises a plasticizer, the weight content of which in the film 2 is, for example, between 10 and 35%. The plasticizer gives the film the desired mechanical properties of strength and flexibility. The plasticizer may be a glycerol, preferably bio-based, so as to be less harmful to the human body and biodegradable.

[0039] The film 2 preferably comprises a crosslinking agent, the weight content of which in the film 2 is, for example, between 3 and 5%. The crosslinking agent increases the mechanical strength of the film 2. The crosslinking agent may be, for example, calcium chloride, or preferably magnesium chloride, which has the advantage of producing a film that is more soluble in water.

[0040] Examples

[0041] A liquid shampoo 1 is wrapped in several different films based on sodium alginate. The comparative film A, which does not contain a surfactant, is not a film according to the invention. Films B, C, D, and E each contain a surfactant; they are made according to the invention.

[0042] The composition of the films is as follows, with the weight contents of the respective components, the total weight of each film being 10 g:

[0043] - Comparative Film A: • 65% “Vivapharm” (registered trademark) Alginate PH R5, • 25% glycerol, • 10% “Vivastar” (registered trademark) CS 052 Alginate. Film B: • 65% “Vivapharm” (registered trademark) Alginate PH R5, • 25% glycerol, • 5% “Vivastar” (registered trademark) CS 052 Alginate, • 5% coco-glucoside. Film C: • 68% “Vivapharm” (registered trademark) Alginate PH R5, • 25% glycerol, 5% “Vivastar” (registered trademark) CS 052 Alginate, 2% coco-glucoside. Film D: 65% "Vivapharm" (registered trademark) Alginate PH R5, 25% glycerol, 5% “Vivastar” (registered trademark) CS 052 Alginate, 5% cocamidopropyl betaine. Film E: 68% "Vivapharm" (registered trademark) Alginate PH R5, 25% glycerol, 5% “Vivastar” (registered trademark) CS 052 Alginate, 2% cocamidopropyl betaine. Film F: 65% "Vivapharm" (registered trademark) Alginate PH R5, 25% glycerol, 5% “Vivastar” (registered trademark) CS 052 Alginate, 5% sodium cocoyl glutamate. ;i I m G : 68% "Vivapharm" (registered trademark) Alginate PH R5, 25% glycerol, 5% “Vivastar” (registered trademark) CS 052 Alginate, 2% sodium cocoyl glutamate. Film H: 65% "Vivapharm" (registered trademark) Alginate PH R5, 25% glycerol, 5% Vivastar (registered trademark) CS 052 Alginate, 5% behentrimonium methosulfate (BTMS). Film I: 68% "Vivapharm" (registered trademark) Alginate PH R5, 25% glycerol, 5% Vivastar (registered trademark) CS 052 Alginate, 2% behentrimonium methosulfate (BTMS). Film J: 55% "Vivapharm" (registered trademark) Alginate PH R5, 20% glycerol, 15% “Vivastar” (registered trademark) CS 052 Alginate, 10% coco-glucoside. Film K: • 35% “Vivapharm” (registered trademark) Alginate PH R5, • 15% glycerol, • 25% “Vivastar” (registered trademark) CS 052 Alginate, • 25% coco-glucoside. Film L: • 60% “Vivapharm” (registered trademark) Alginate PH R5, • 25% glycerol, • 15% coco-glucoside.

[0044] Vivapharm (registered trademark) Alginate PH R5 is a sodium alginate with a viscosity of 200-500 mPa s used as a main component.

[0045] Vivastar (registered trademark) CS 052 Alginate is a sodium alginate with a viscosity of 3000-6000 mPa s used as a thickening agent.

[0046] Glycerol is used as a plasticizer.

[0047] Coco-glucoside, cocamidopropyl betaine, sodium cocoyl glutamate and behentrimonium methosulfate (BTMS) are used as surfactants.

[0048] The comparative film A and the films according to the invention B to L are prepared by a method similar to "casting": for each film, the ingredients are dispersed in 30 ml of water, then each solution is placed in a polyolefin container. After two to three hours of air drying, films with a thickness of 40 to 50 µm are formed.

[0049] Ingredients for 50 cl of liquid shampoo 1:

[0050] - 20 g of Marseille soap, - 40 cl of water, - 1 tablespoon of baking soda, - 10 drops of tea tree essential oil. - 1 tablespoon of honey, - 1 tablespoon of coconut oil,

[0051] Liquid shampoo 1 is prepared according to the following protocol:

[0052] - grating of Marseille soap, - Introduce the soap flakes and water into a metal container heated over medium heat, stirring constantly. - cooling and hardening of the preparation, - adding baking soda and tea tree essential oil, - adding water to make the mixture less compact, - adding coconut oil, - Mix until the desired consistency is reached.

[0053] A first test was carried out to evaluate the foaming power of the assembly according to the invention. This is a comparative test based on the liquid shampoo 1 described below. above, in which we compare the results of liquid shampoo 1 alone, liquid shampoo 1 wrapped in comparative film A, and liquid shampoo 1 wrapped in films according to the invention B to L.

[0054]

[0055]

[0056]

[0057] The protocol for the first test is as follows: introduction into a first beaker of 250 ml of water at 35°C + 20 ml of liquid shampoo 1 without packaging, introduction into a beaker A, respectively B to L, of 250 ml of water at 35°C + 20 ml of liquid shampoo 1 packaged in the comparative film A, respectively the film according to the invention B to L. introduction of a magnetic stirrer into each of the thirteen beakers, simultaneous start-up of the stirrers, measurement of the fill level of each beaker after 5 minutes of stirring. The following measures were taken: The first beaker contains 260 ml of solution. Beaker A contains 260 ml of solution, beaker B contains 285 ml of solution, beaker C contains 280 ml of solution, beaker D contains 285 ml of solution, beaker E contains 280 ml of solution, beaker F contains 295 ml of solution, beaker G contains 290 ml of solution, beaker H contains 275 ml of solution, beaker I contains 270 ml of solution, beaker J contains 290 ml of solution, beaker K contains 300 ml of solution, beaker L contains 295 ml of solution.

[0058] Since the measurements are identical for the first beaker and beaker A, the shampoo Liquid 1 packaged in comparative film A, which does not contain a surfactant, did not produce more foam than liquid shampoo 1 used without film 1. Comparative film A, when dissolved in water, does not provide any additional foaming power to liquid shampoo 1.

[0059] Furthermore, a larger volume was measured in beakers B to L than in the first beaker; it can be deduced from this that the liquid shampoo 1 packaged in one of the films according to the invention B to L produced more foam than the liquid shampoo 1 used without film 1, or than the liquid shampoo 1 packaged in the comparative film A, which does not contain a surfactant. This shows that the surfactant imparts a foaming effect to the assembly according to the invention.

[0060] A larger volume was measured in beaker K than in beaker L, In beaker L than in beaker J, in beaker J than in beaker B, and in beaker B than in beaker C, the first test shows that for a given surfactant, in this case coco-glucoside, the amount of foam produced by using the assembly according to the invention is greater the higher the weight content of the surfactant. This is also true for the other surfactants tested: for betaine cocamidopropyl, beaker D is more full than beaker E; for sodium cocoyl glutamate, beaker F is more full than beaker G; and for behentrimonium methosulfate (BTMS), beaker H is more full than beaker I.

[0061] Finally, this first test shows that some surfactants have a stronger foaming effect than others, at the same concentration in the films. The measurements show that sodium cocoyl glutamate, an anionic surfactant, has a greater foaming power than coco-glucoside, a non-ionic surfactant, which itself has a greater foaming power than cocamidopropyl betaine, an amphoteric surfactant, which itself has a greater foaming power than behentrimonium methosulfate (BTMS), a cationic surfactant.

[0062] Thus, when designing a film according to the invention, for a desired foaming effect, the minimum weight content of surfactant may be higher for a cationic type surfactant, for example at least 5%, than for an anionic type surfactant, for example at least 1%.

[0063] A second test was carried out to evaluate the emulsifying power of the assembly according to the invention. This is a comparative test based on the liquid shampoo 1 described above, in which the results of the liquid shampoo 1 alone, of the liquid shampoo 1 wrapped in the comparative film A, and of the liquid shampoo 1 wrapped in the films according to the invention B to L are compared.

[0064] The second test is based on the fact that an emulsifying agent added to immiscible products, such as water and oil, causes a macroemulsion, i.e., the formation of small oil droplets in the water called micelles. The bubbles and droplets are visualized using a Keyence VHX 5000 digital microscope (see illustration in [Fig. 2]). The size of the micelles ranges from 50 to 150 micrometers and they are visible to the naked eye. The number of oil micelles is higher, and their size is smaller, when the product has a greater emulsifying power.

[0065] The protocol for the second test is as follows:

[0066] - Introducing 250 ml of water and 8 drops of colored oil into a first beaker, as well as beakers A to L. After stirring, it is observed that the oil does not disperse in the water. - Add 10 ml of liquid shampoo 1 to the first beaker, - addition of 10 ml of liquid shampoo 1 wrapped in comparative film A, respectively B to L, into beakers A, respectively B to L, - introduction of a magnetic stirrer into each of the thirteen beakers, - simultaneous start-up of the thirteen agitators, - The macroemulsions produced in each beaker are observed after 10 minutes of stirring using an optical microscope. A representative photograph of all the micelles is taken for each of the emulsions taken from the first beaker and from beakers A to L, and the images obtained are analyzed using processing software to obtain the micelle size distribution.

[0067] The following measures were carried out:

[0068] - in the first beaker, the majority of the droplets have a diameter of approximately 130 µm, - in beaker A, the majority of droplets have a diameter of approximately 130 µm, - in beaker B, the majority of droplets have a diameter of approximately 110 µm, - in beaker C, the majority of droplets have a diameter of approximately 115 µm, - in beaker D, the majority of droplets have a diameter of approximately 110 µm, - in beaker E, the majority of droplets have a diameter of approximately 115 µm, - in beaker F, the majority of droplets have a diameter of approximately 105 µm, - in beaker G, the majority of droplets have a diameter of approximately 110 µm, - in beaker H, the majority of droplets have a diameter of approximately 115 µm, - in beaker I, the majority of droplets have a diameter of approximately 126 µm, - in beaker J, the majority of droplets have a diameter of approximately 100 µm, - in beaker K, the majority of droplets have a diameter of approximately 90 µm, - in beaker L, the majority of droplets have a diameter of approximately 95 µm.

[0069] Since the measurements are identical for the first beaker and beaker A, the shampoo Liquid 1 packaged in comparative film A, which does not contain a surfactant, does not have a higher emulsifying power than liquid shampoo 1 used without film 1. Comparative film A, when dissolved in water, does not provide additional emulsifying power to liquid shampoo 1.

[0070] Furthermore, smaller micelle sizes were measured in beakers B to L than in the first beaker; it can be deduced from this that the liquid shampoo 1 packaged in one of the films according to the invention B to L has a higher emulsifying power than the liquid shampoo 1 used without film 1, or than the liquid shampoo 1 packaged in the comparative film A not containing a surfactant. This shows that the active surfactant confers an emulsifying effect to the assembly according to the invention.

[0071] Smaller micelle sizes having been measured in beaker K than in beaker L, in beaker L than in beaker J, in beaker J than in beaker B, and in beaker B than in beaker C, the second test shows that for a given surfactant, in this case coco-glucoside, the emulsifying power provided by the assembly according to the invention is all the more important as the weight content of the surfactant is greater. This is also true for the other surfactants tested: for betaine cocamidopropyl, smaller micelle sizes were measured in beaker D than in beaker E, for sodium cocoyl glutamate, smaller micelle sizes were measured in beaker F than in beaker G, and for behentrimonium methosulfate (BTMS), smaller micelle sizes were measured in beaker H than in beaker I.

[0072] Finally, this second test shows that some surfactants have a stronger emulsifying effect than others, at the same concentration in the films. The measurements show that sodium cocoyl glutamate, an anionic surfactant, has a greater emulsifying power than coco-glucoside, a non-ionic surfactant, which itself has a power equivalent to that of cocamidopropyl betaine, an amphoteric surfactant, which itself has a greater foaming power than behentrimonium methosulfate (BTMS), a cationic surfactant.

[0073] Thus, when designing a film according to the invention, for a desired emulsifying effect, the minimum weight content of surfactant may be higher for a cationic type surfactant, for example at least 5%, than for an anionic type surfactant, for example at least 1%.

[0074] A third test was carried out to evaluate the moisturizing power of the assembly according to the invention when it includes a thickening agent. This is a comparative test based on the liquid shampoo 1 described above, in which the results of liquid shampoo 1 alone, liquid shampoo 1 wrapped in the comparative film A, and liquid shampoo 1 wrapped in the films according to the invention B, D, F, H, J are compared. KetL.

[0075] In the third test, the moisturizing efficacy of the water-soluble film is evaluated by a visual skin wettability test performed on the flat surface of a user's forearm. The visual test consists of assessing the degree to which the water spreads on the skin surface of the forearm in order to reveal its hydrophobic or hydrophilic tendency. To do this, a contact angle θ can be visualized when a drop of a liquid is deposited on the skin surface. As illustrated in [Fig. 3], in a cross-sectional view of the skin surface 3 and passing through the center of the drop 4, the contact angle θ is the angle between the skin surface and the line tangent to the drop at its point of contact with the skin. Once formed on the surface, the drop may maintain its shape or spread out, thus increasing the contact area. An untreated skin surface tends to be hydrophobic: the contact angle 0 is then close to 90° at the level of the forearm.For a drop placed on hydrated skin, the contact angle 0 decreases.

[0076] The protocol for the third test is as follows, and is identical for the comparative film A and each film B, D, F, H, J, K and L:

[0077] - introduction into a beaker of 49.5 g of water at 30 °C, - adding to the beaker a 5.5g piece of the film, previously cut into bands, - introduction of a magnetic stirrer into the beaker, - starting the stirrer until the film is completely dissolved, - impregnation of a washcloth with the solution contained in the beaker, - static application of the washcloth to a treatment area on the user's forearm for two minutes, - drying the forearm with a towel, - placing a drop of water on the treated area of ​​the forearm, - observing the degree of spreading of the water drop, estimating the contact angle 0.

[0078] The last two steps of the protocol are also applied to an untreated area of ​​the user's forearm.

[0079] The following measures were carried out:

[0080] - untreated area: the contact angle 0 is close to 90°, - area treated with comparative film A: the contact angle 0 is approximately 65°, - area treated with film B: the contact angle 0 is approximately 70°, - area treated with film D: the contact angle 0 is approximately 70°, - area treated with film F: the contact angle 0 is approximately 70°, - area treated with film H: the contact angle 0 is approximately 70°, - area treated with film J: the contact angle 0 is approximately 60°, - area treated with film K: the contact angle 0 is approximately 50°, - area treated with film L: the contact angle 0 is approximately 80°,

[0081] Since the contact angle is greater with film L, which does not contain a thickening agent, than with the comparative film A and films B, D, F, H, J, and K, which do contain a thickening agent, the results of the third test show that the areas treated with a film containing a thickening agent are better hydrated than the areas treated with a film that does not contain a thickening agent. The thickening agent therefore does indeed provide a hydrating property to the films according to the invention, and even to the comparative film A, which does not contain a surfactant.

[0082] Furthermore, since the contact angle θ is lower for the surface treated with film K than with film J, with film J than with the comparative film A, and with the comparative film A than with films B, D, F, and H, it is shown that the moisturizing properties are all the more important as the film's thickening agent content is higher. This is also verified with the comparative film A, and is therefore independent of the presence of the surfactant.

[0083] Although the above description is based on particular embodiments, it is in no way limiting of the scope of the invention, and modifications may be made, in particular by substitution of technical equivalents or by different combination of all or part of the features developed above.

Claims

Claims

1. Assembly comprising a shower or bath hygiene product (1) and a film (2), wherein said shower or bath hygiene product (1) is wrapped in said film (2), characterized in that said film (2) is soluble in water, and in that said film (2) comprises at least: - a main component consisting of sodium alginate, the content by weight of which in said film is greater than or equal to 25%, and - a surfactant.

2. An assembly according to the preceding claim, wherein the weight content of said surfactant in said film (2) is between 1 and 30%.

3. Assembly according to one of the preceding claims, in which the surfactant is of natural origin, of non-ionic or anionic type.

4. An assembly according to one of the preceding claims, wherein the dynamic viscosity of the sodium alginate of the main component of the film (2) is between 200 and 500 mPa s.

5. Assembly according to one of the preceding claims, in which said film (2) further comprises a glycerol, the content by weight of which in said film (2) is between 10 and 35%.

6. An assembly according to one of the preceding claims, wherein said film (2) further comprises a crosslinking agent such as magnesium chloride, the content by weight of which in said film (2) is between 3 and 5%.

7. Assembly according to one of the preceding claims, in which said film (2) further comprises a thickening agent, the content by weight of which in said film (2) is between 1 and 30%.

8. Assembly according to the preceding claim, in which the thickening agent is a sodium alginate whose dynamic viscosity is between 3000 and 6000 mPa s.

9. Use of an assembly according to one of the preceding claims, wherein said film (2) is dissolved upon contact with water, releasing said surfactant from said film, said surfactant providing emulsifying and / or foaming properties to said hygiene product. shower or bath (1) by mixing with it.

10. Use according to the preceding claim of an assembly according to one of claims 7 to 8, in which the dissolution of the film (2) releases said thickening agent, the latter providing moisturizing properties to said shower or bath hygiene product (1) by mixing with it.

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