Applicator device for applying a fluid or pasty cosmetic product obtained by molding a polymer mixture

Abstract

The present invention relates to an application member for applying a cosmetic product, in particular for applying a fluid or pasty product to keratinous fibers, such as eyelashes or eyebrows. The application member is obtained by molding or by addition of material, from a polymer mixture comprising at least two distinct thermoplastic elastomer polymers.

Description

APPLICATOR DEVICE FOR A FLUID OR PASTY COSMETIC PRODUCT OBTAINED BY MOLDING A MIXTURE OF POLYMERS

[0001] The present invention relates to the field of applicator devices for applying fluid or paste-like cosmetic products to keratin fibers or the epidermis. In particular, the invention relates to applicators designed from specific polymer materials, adapted to the performance and chemical compatibility requirements of modern cosmetic formulations.

[0002] STATE OF THE ART

[0003] Currently, there are applicator devices for applying fluid or paste-like products to keratin fibers, such as mascara brushes, lip gloss applicators, or makeup tools for eyelashes, eyebrows, or lips. These devices comprise an elongated central core extending along a longitudinal axis, and at least one row of elongated bristles with one end embedded in the core and the other free. Typically, the bristles and the core are formed from a single molded piece. For example, document EP3261487B1 describes such applicator devices.In particular, this type of applicator device is obtained by molding at least one thermoplastic elastomer material such as Hytrel®, Sipolprene®, Copec® (TPE-C), SEBS Cawiton®, Pebax® (TPE-S), Pebax® (TPE-PA), or a thermoplastic material such as Exact®, Queo®, Flexirene® (PE, LDPE, LLPE), Engage® (TPO), Santoprene® (TPV), a TPU, NEO by SIMP®, or a thermosetting material such as silicone, PU, ​​or NBR, which are the materials that professionals currently use for this type of molded applicator device. Similarly, other documents such as US 7,866,906 and WO 2013 / 153528 describe applicators made from polymers, optimized for specific criteria such as chemical resistance or cosmetic finish properties.

[0004] However, these approaches have significant limitations that cannot simultaneously and optimally meet complex and sometimes conflicting requirements, such as: good mold processability, mechanical and aesthetic performance adapted to the application, and chemical compatibility with potentially aggressive cosmetic formulas.

[0005] Thermoplastic polymers, such as TPE-S, PE, TPO, and TPE-PA, offer a degree of flexibility and satisfactory mechanical properties but sometimes exhibit limitations in terms of chemical resistance. Conversely, polymers like TPE-C, TPE-E, and TPV are chemically stable but often lack flexibility or compatibility with complex molding processes.

[0006] These compromises mean that professionals are often forced to prioritize good chemical resistance at the expense of tactile softness or application efficiency, and vice versa. For example, a polymer like Hytrel® offers good chemical resistance but may limit the cosmetic finish or the soft feel expected by the user.

[0007] There is therefore an unmet need for a material that can reconcile the requirements mentioned above, while overcoming the limitations inherent in the use of these polymers.

[0008] DESCRIPTION OF THE INVENTION

[0009] The present invention proposes an applicator device made from a synergistic blend of at least two different types of polymers, selected to exploit the complementary advantages of each. This blend, which may include thermoplastic elastomeric polymers (TPE-E, TPE-S, TPE-C, TPE-PA) or thermoplastic polymers (PE, LDPE, TPO, etc.), enables: - Maintain excellent chemical resistance, avoiding swelling effects or component transfers; - Maintain a soft feel and optimal makeup finish; - To ensure good processability by molding for efficient industrial production.

[0010] People skilled in the art have traditionally been discouraged from combining different types of polymers, due to fears of chemical or physical incompatibility problems, such as phase shifting of the components, The alteration of mechanical properties or difficulties during molding. Such a combination would be counterintuitive, as it requires solving complex problems related to material homogeneity and adaptation to the requirements of industrial processes.

[0011] Surprisingly, by combining different types of polymers, the invention overcomes traditional compromises. This innovative approach achieves superior mechanical, aesthetic, and chemical performance, while meeting the expectations of end users and manufacturers.

[0012] A first object of the invention is an applicator device for applying a fluid or paste-like product to keratin fibers, comprising an application member obtained at least partially by molding or by adding material from a mixture of polymers comprising two different types of polymers, said types of polymers being selected from TPE-E (thermoplastic elastomers based on copolyesters), TPE-C (thermoplastic elastomers based on crystalline copolymers), TPE-S (thermoplastic elastomers based on styrene), TPE-PA (thermoplastic elastomers based on polyamides), PE (polyethylene), LDPE (low-density polyethylene), LLDPE (linear low-density polyethylene), TPO (thermoplastic polyolefins), TPV (thermoplastic vulcanized materials), TPU (thermoplastic polyurethane), PDMS (polydimethylsiloxane) and PU (polyurethane).

[0013] The application of a fluid or paste-like product to keratin fibers, skin, and mucous membranes refers to the process of depositing, distributing, or spreading a cosmetic or skincare product with a liquid, semi-liquid, or viscous consistency onto biological structures composed of keratin, such as hair (for products like hair dyes, hair care products, or styling treatments), eyelashes (for mascaras or conditioning and strengthening products), eyebrows (for specific gels or dyes), and body hair (for conditioning, coloring, or styling products). This process generally aims to modify the appearance, texture, color, or structure of the keratin fibers, or to provide them with protective, restorative, or beautifying properties.

[0014] In one embodiment, the application member comprises an elongated central core extending along a longitudinal axis, and a plurality of prongs formed from a moldable material derived from the mixture. An example of an application member according to the invention is shown in Figures 1 to 9.

[0015] The application element is obtained at least partially by molding or by adding material from a mixture of polymers.

[0016] Preferably, at least part, preferably all, of the bumps are made in the polymer mixture according to the invention, preferably as a unit with the core, preferably in the same material.

[0017] The molding process involves shaping a material, in this case a polymer blend, by introducing it in a molten or semi-molten state into a mold with a predefined geometric cavity. Once the material has solidified in the mold, it takes on the desired shape, whether a simple or complex structure.

[0018] The additive manufacturing process refers to the successive or simultaneous deposition of multiple layers or quantities of material. In this case, the polymer mixture can be injected, extruded, or deposited using additive manufacturing processes such as 3D printing.

[0019] Advantageously, but optionally, the device according to the invention has or includes at least one of the following technical characteristics: - the device has an elongated core extending along a main longitudinal axis XX and having a longitudinal cylindrical shape, and a plurality of pins distributed on said core; - each pin extends from an end anchored in the core to a free end and is formed in one piece with said core; - the device also includes a rod extending in line with the core along the main longitudinal axis XX; and - the device also includes a cap mounted on the stem.

[0020] The invention also relates to a makeup set comprising an applicator device for applying a fluid or paste product onto fibers keratinous, the lips or an epidermis and comprising an applicator device having at least one of the above technical characteristics, a reservoir and a wringing device mounted on a neck of the reservoir.

[0021] The polymer blend according to the invention refers to a specially formulated composition made from at least two distinct types of polymers, selected from thermoplastic elastomers (TPEs) and other thermoplastic or thermosetting materials. Thermoplastics are polymers that, under the effect of heat, melt or soften, allowing them to be shaped by molding or injection, and then solidify upon cooling, without any chemical alteration of their structure (see ISO 18064:2014). The thermoplastic elastomers used in this invention are a particular class of polymers combining elastic properties similar to those of rubber and thermoplastic properties that facilitate their processing.

[0022] For general information on thermoplastic elastomer materials, one can refer in particular to the guide of Engineering Techniques, Treatise on Plastics and Composites, AM 3 400 by Michel Biron published on July 10, 2000.

[0023] The present invention lies in the combination of different types of polymers, which is counterintuitive to those skilled in the art, as these polymers often exhibit structural or functional incompatibilities. However, by balancing the proportions and optimizing the formulation, it is possible to obtain a material with synergistic characteristics, such as improved flexibility, increased chemical resistance to aggressive cosmetic formulas, and superior applicator performance.

[0024] The said types of polymers according to the invention are selected from TPE-E (thermoplastic elastomers based on copolyesters), TPE-C (thermoplastic elastomers based on crystalline copolymers), TPE-S (thermoplastic elastomers based on styrene), TPE-PA (thermoplastic elastomers based on polyamides), PE (polyethylene), LDPE (low-density polyethylene), LLDPE (linear low-density polyethylene), TPO (thermoplastics polyolefins), TPV (thermoplastic vulcanized), TPU (thermoplastic polyurethane), PDMS (polydimethylsiloxane) and PU (polyurethane).

[0025] TPE-E (thermoplastic elastomers based on copolyesters) are polymers composed of rigid copolyester blocks and flexible blocks, generally based on polyethers. This type of polymer is known for its combination of mechanical strength and flexibility, offering good abrasion resistance and excellent thermal stability. For example, Hytrel® is a commonly used TPE-E, with typical hardness values ​​ranging from 30 to 82 Shore D. These materials are valued for their chemical compatibility with many cosmetic formulas and their ability to retain their properties even under prolonged mechanical stress.

[0026] TPE-C (Thermoplastic Elastomeric Crystalline Copolymers), also known as crystalline ether-ether or ether-ester copolymers, exhibit excellent chemical resistance and good elasticity. These polymers, such as Sipolprene®, offer a wide range of hardness, typically between 40 Shore A and 75 Shore D, depending on the specific composition. They are often used in applications requiring a combination of flexibility and chemical resistance, particularly for products exposed to aggressive formulations or temperature variations.

[0027] TPE-S (thermoplastic elastomers of styrene) are block copolymers comprising a rigid styrene segment and an elastic segment, often made of polybutadiene or polyisoprene. These polymers, such as SEBS (polystyrene-ebony-butylene-styrene), like Cawiton®, are known for their flexibility and ability to provide a soft-touch texture. They typically have hardnesses ranging from 10 to 90 Shore A, making them suitable for applications where comfort and flexibility are essential.

[0028] TPE-PA (thermoplastic elastomers based on polyamides) are hybrid materials combining rigid polyamide blocks and flexible segments such as polyether. An example is Pebax®, which is often used for products requiring excellent chemical resistance and good elasticity. These polymers have hardness ranges from 30 to 72 Shore D and offer exceptional durability, even in contact with cosmetic formulas containing solvents or oils.

[0029] Polyethylene (PE) is a simple yet versatile polymer, available in various densities, including high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE). PE is valued for its flexibility, chemical resistance, and ease of processing. For example, Exact® and Flexirene® are polyethylenes with typical Shore D hardness values ​​between 20 and 40.

[0030] LDPE (Low-Density Polyethylene) is a softer and more elastic form of PE, often used to improve the flexibility of mixtures. It offers satisfactory chemical resistance and low stiffness, with typical hardness values ​​around 20-30 Shore D.

[0031] LLDPE (Linear Low-Density Polyethylene) is similar to LDPE but has a linear molecular structure, which improves its mechanical properties, particularly tensile and impact strength. LLDPE formulations, such as Queo®, exhibit hardnesses close to 30 Shore D and are used to increase the robustness of a mixture without compromising its flexibility.

[0032] Thermoplastic polyolefins (TPOs) are blends of elastomers and polyolefins such as polypropylene or polyethylene. TPOs, like Engage®, offer excellent impact resistance and chemical stability in the face of aggressive cosmetic formulas. They have a Shore A hardness ranging from 40 to 90, depending on the formulation.

[0033] Vulcanized thermoplastics (TPVs) are hybrid materials comprising vulcanized elastomers dispersed in a thermoplastic matrix, often polypropylene. TPVs, such as Santoprene®, combine rubber-like elasticity with the recyclability of thermoplastics. Their hardness ranges from 50 Shore A to 60 Shore D, and they are ideal for applications requiring good chemical resistance.

[0034] TPU (Thermoplastic Polyurethane) is a polyurethane-based polymer offering an excellent combination of flexibility and chemical resistance. and wear resistance. TPUs, such as those in the Estane® range, have hardnesses between 60 Shore A and 85 Shore D and are commonly used for products requiring high durability and elasticity.

[0035] PDMS (Polydimethylsiloxane) is a silicone-based polymer widely recognized for its elastic properties and exceptional chemical resistance. It is used to improve the softness of the touch and compatibility with harsh cosmetic formulas. PDMS-based formulations, such as NEO by SIMP®, typically have low hardness, between 10 and 50 Shore A.

[0036] Polyurethane (PU) is a thermosetting or thermoplastic polymer offering excellent mechanical and chemical resistance. Used in blends to enhance durability, it exhibits hardnesses ranging from 40 Shore A to 95 Shore D depending on its formulation, making it particularly versatile for cosmetic applications.

[0037] According to one embodiment, the polymer mixture comprises: - between 5% and 95%, preferably between 20% and 80%, more preferably between 30% and 70%, or even more preferably between 40% and 60% by weight of a first polymer, and - between 5% and 95%, preferably between 20% and 80%, more preferably between 30% and 70%, even more preferably between 40% and 60% by weight of a second polymer of a different type.

[0038] In another embodiment, the polymer blend is designed based on a predefined weight ratio between the two main polymers. For example, the blend may have a weight ratio of 1:1, i.e., 50% by weight of the first polymer and 50% by weight of the second polymer. Alternatively, asymmetrical ratios, such as 2:1 (approximately 67% for the first polymer and 33% for the second) or 3:2 (approximately 60% and 40%, respectively), may be considered to precisely adjust the mechanical, elastic, or chemical properties of the material to meet the specific requirements of the application.

[0039] According to a preferred embodiment of the invention, the first polymer is a TPE-C or a TPE-E and the second polymer is selected from TPE-S, TPU or TPE-PA.

[0040] According to one embodiment, the polymer mixture comprises: - between 5% and 95%, preferably between 30% and 95%, more preferably between 50% and 90%, and even more preferably between 60% and 85% by weight of a first polymer selected from a TPE-C or a TPE-E, and - between 5% and 95%, preferably between 5% and 60%, more preferably between 10% and 50%, even more preferably between 15% and 40% by weight of a second polymer selected from a TPE-S, TPU or TPE-PA.

[0041] According to one embodiment of the invention, the mixture further comprises 1% to 30% by weight of a third polymer selected from PDMS, PE or TPO, to improve the device according to the invention.

[0042] According to a particular embodiment, the polymer mixture contains at least 15% by mass of polyolefin filler, preferably at least 20%, or even at least 35%.

[0043] Depending on the case, it may be useful to add up to 45% or even up to 50 or 55% by mass of polyolefin filler.

[0044] Preferably, the polyolefin filler comprises polyethylene, or is even made entirely of polyethylene. In particular, the polyethylene may be high-density (HD), low-density (LD), very low-density (VLD), linear low-density (LLD), or radical low-density (RLD). Preferably, it is high-density polyethylene.

[0045] Advantageously, the polymer mixture contains at most 70% by mass of polyolefin filler, preferably less than 60% by mass.

[0046] According to one embodiment, the application member according to the invention has a tensile strength between 2 MPa and 100 MPa, preferably between 10 MPa and 60 MPa and / or an elongation at break greater than 200%, preferably 500%.

[0047] The tensile strength (“Ultimate Tensile Strength” or “Tensile Strength”) is determined in accordance with DIN 53504 / ISO 37 on a standard S2 specimen with a speed (“traverse speed”) of 200 mm per minute.

[0048] Advantageously, the material according to the invention has a tensile strength of 25 MPa or less. This maximum value ensures, in particular, a certain flexibility in application and user comfort.

[0049] Preferably, the material according to the invention has an elongation at break greater than or equal to 400%, preferably greater than or equal to 5600%. This ensures good elasticity of the application member and / or its application elements. The elongation at break is measured using the same method as the tensile strength.

[0050] Preferably, the polymer blend has an elongation at break of less than or equal to 700%, preferably less than or equal to 600%.

[0051] In an advantageously complementary manner, the polymer blend exhibits a tear resistance greater than or equal to 20 N / mm, or even greater than or equal to 60 N / mm.

[0052] Tear resistance is measured according to ISO 34-1, method B (b) (Graves).

[0053] Advantageously, the polymer blend has a hardness greater than or equal to 20 Shore A, preferably greater than or equal to 40 Shore A, or even greater than or equal to 60 Shore A. Such a hardness is particularly suitable for cosmetic product applicators.

[0054] Advantageously, the polymer blend has a hardness of less than or equal to 110 Shore A (equivalent to about 70 Shore D), preferably less than or equal to 100 Shore A (equivalent to about 60 Shore D).

[0055] In particular, for a mascara brush type applicator and more generally for hair and nails, a hardness between 60 Shore A and 80 Shore D, or even from 45 Shore A to 90 Shore D, should be chosen.

[0056] For lip or skin type applicators, a slightly less hard material should be chosen, with a hardness between 30 and 100 Shore A, preferably 60 to 80 Shore A.

[0057] According to one embodiment, the applicator device according to the invention can be formed by an assembly of washer-shaped elements on a rod or support. This rod or support can, for example, be of a twisted metal type as described in the following applications or patents: JP4598360(B2), FR2810861A1, EP3324785(B1), FR2890837(B1) and in particular FR3117000A1, which describes an assembly of a washer on a molded rod or the winding of a spiked blade around an axis, as well as WO2024033431 (A1), which relates to an assembly on a twisted steel rod, and US4422986A, describing an assembly of flat-bodied washers. In this context, according to the invention, the washer-shaped elements can be formed by molding or by adding material from a mixture of material according to the invention.

[0058] Another aspect of the invention relates to a mixture of polymers as described above for its use in the manufacture of an applicator device intended for the application of a fluid or paste-like product onto keratin fibers.

[0059] Another aspect of the invention relates to a method for manufacturing an applicator device for applying a fluid or paste-like product to keratin fibers or the epidermis, characterized in that it comprises the following steps: a) Preparing a mixture comprising at least two polymers of different types, said types of polymers being selected from TPE-E (thermoplastic elastomers based on copolyesters), TPE-C (thermoplastic elastomers based on crystalline copolymers), TPE-S (thermoplastic elastomers based on styrene), TPE-PA (thermoplastic elastomers based on polyamides), PE (polyethylene), LDPE (low-density polyethylene), LLDPE (linear low-density polyethylene), TPO (thermoplastic polyolefins), TPV (thermoplastic vulcanized materials), TPU (thermoplastic polyurethane), PDMS (polydimethylsiloxane) and PU (polyurethane); b) Heat the mixture to reach a temperature that allows it to be put into work by molding or by adding material; c) Inject or mold the mixture into a mold configured to form the application member of the device; d) Cool and demold the applicator device.

[0060] According to one embodiment, the polymers are mixed in a molten state at a temperature between 160 °C and 250 °C.

[0061] DESCRIPTION OF THE FIGURES

[0062] Figure 1 is a perspective view of a makeup set comprising a cosmetic product applicator device according to the invention. This set includes, on the one hand, a container or reservoir 10 having a neck 5, and a wiping device 11 disposed in the neck 5. On the other hand, this set includes a rod 12, a cap or gripping handle 13, and a cosmetic product applicator device 14, fixed to each other to form a removable assembly with respect to the reservoir 10 and the wiper seal 11. All the elements listed above are, in general, rotationally symmetrical about the main longitudinal axis XX of the makeup set, unless otherwise indicated herein.

[0063] Figure 2 is a perspective view of the applicator device of Figure 1 according to one embodiment. The applicator device 14 according to the invention is, in this case, a mascara brush. It comprises a core 2 extending longitudinally along a principal longitudinal axis XX. The core 2 may have a constant or variable cross-section over its length. In most common embodiments, the cross-section is either constant or decreases from a proximal end engaged with a tube and / or a gripping handle to a free distal end. Generally, the core 2 is cylindrical overall, preferably of revolution about the principal longitudinal axis XX. Thus, the cross-section of the core 2 may be circular, polygonal, oval, or other shape. It may be axisymmetric. The core 2 may be solid or hollow.The person skilled in the art will choose the most appropriate core based on economic and / or technical constraints. Furthermore, the applicator device 14 according to the invention comprises a plurality of pins 15 distributed on the core 2. The pins 15 project from a surface. The outer periphery of the core 2. The pins 15 are, for example, formed from the material along with the core 2. In particular, the pins 15 are obtained by molding with the core 2. Here, as illustrated, the pins 15 are arranged in adjacent rows, two by two, extending longitudinally parallel to the main longitudinal axis XX. The pins 15 in the same row extend in the same way, with the same orientation, parallel to each other, from the core 2. Here, considering two adjacent rows, the pins 15 in one of the adjacent rows are oriented differently from the pins 15 in the other adjacent row, for example, as illustrated in Figure 1, at 180°. Alternatively, the orientation is 90°. Other shapes and / or arrangements of pins 15 are possible without going out of scope of the invention and are widely documented in documents already published on this subject.

[0064] Figure 3 shows a perspective view of an applicator device similar to that of Figure 2, with a difference in the configuration of the pins (15). Unlike Figure 2, where the pins have a marked curvature, the pins in Figure 3 are straight and oriented radially from the core (2).

[0065] Figures 4A, 4B, and 4C show a more detailed example of an applicator device according to the invention: these figures show that the applicator device comprises, in particular, at least one flexible longitudinal arch 10, 11 fixed at at least one point 101, 111, 112 to a web 15. The web is understood to be the solid volume constituting the device, excluding the arch(s) 10, 11. The web extends longitudinally along the axis XX. The elastic arch(s) can be of two types: either fixed to the web 15 at two points; preferably, as illustrated, these two points are located at each end of the arch 11. The fixed point(s) can be located elsewhere without departing from the scope of the invention. According to another type, the arches 10 are fixed at a single point 101; This point is notably located at one of the ends of the arch 10, which is thus arranged in cantilever over the web 15.Greater flexibility is thus conferred to this type of arch 10. Arches 10 and 11 themselves are elongated and thin (length-to-thickness ratio of approximately 10 / 1) in order to inherently exhibit a certain degree of flexibility. to give the general external shape characteristic of the invention, the arch(s) 10, 11 have a wavy shape along the axis XX. In figures 4A, 4B and 4C the device comprises an arch 10 embedded at a single point 101, and a plurality of arches 11 embedded at two points 111, 112.

[0066] In Figures 5A and 5B, the device comprises several cantilevered arches 10, radially surrounded by arches 11 fixed at both ends 111, 112. The arches 10, 11, together with the web 15, define a product reservoir of variable volume, capable of pumping the product contained within it. The reservoir is defined here as the volume between the arches 10, 11 and the web 15. Since the arches are flexible, their deformations generate a variation in the reservoir's volume, thus pumping the fluid or pasty product. A person skilled in the art will choose the number and arrangement of the arches 10, 11 based on various parameters.

[0067] Figures 6A, 6B, 6C, and 6D illustrate an embodiment in which the arches are all of type 11, that is, fixed at two points 111 and 112. The arches 11 are identical to each other and distributed within a cylindrical hemisphere; they are regularly spaced at regular angles, as clearly shown in Figures 6B and 6D. The second hemisphere 6 can be solid or hollow, according to the craftsman's preference.

[0068] Figure 7A illustrates a specific example where a single arch 11 is provided, fixed at both ends. Figures 7B to 7E, in contrast, represent, through schematic cross-sections, different variations corresponding to different arch positions; Figure 7B is a cross-section of the device as shown in Figure 7A, along section AA. According to Figure 7C, three substantially identical arches are provided, placed side by side within a small angular sector (approximately 90°). As shown in Figure 7D, three arches are provided; they are not identical in shape, in particular one is thicker and therefore more rigid than the others. Again, a person skilled in the art will choose the shape most appropriate to the intended application.

[0069] Figures 8A and 8B show an example of an embodiment where all the arches 11 are fixed at each end. They are regularly spaced at angles and have different shapes. Although this concept may seem difficult to achieve, currently available technologies allow for easy, mass production.

[0070] Figure 9 illustrates an applicator element comprising an applicator device according to the invention. It is clearly seen that the device cooperates with the rod 5 and is supported at its opposite end by a gripping means of the type of container closure cap, which is well known per se. According to Figure 9, the device has a generally peanut-shaped external form and comprises three cantilevered arches 10 angularly surrounded by arches 11.

[0071] Figure 10 presents a visual comparison of cosmetic brushes made from different materials, in three distinct states: without formula, with formula before application, and with formula after application. The three materials tested are HYTREL® 45D, SEBS 88A, and MXP 35D, the latter being the polymer blend according to the invention (see example 3).

[0072] Figure 11 illustrates photographs of human eyelashes under four different conditions: without makeup, and after application of makeup using brushes made of three distinct materials (HYTREL® 45D, SEBS 88A, and MXP 35D, the latter being the polymer blend according to the invention). These images allow visualization of the effects of each brush on the final appearance of the eyelashes (see example 4).

[0073] EXAMPLES

[0074] Example 1: Load tests

[0075] To evaluate the performance of the polymer blend according to the invention (hereinafter referred to as "MXP"), comparative load tests were conducted using a SIMP® VC0037 cosmetic brush, a widely distributed catalog model sold to makeup brands. This brush is mounted on a shaft and covered by a cap. Three distinct materials were tested (see Table 1 below): Hytrel® 45D (HYT 45D), SEBS 88A, and MXP (polymer blend according to the invention), a blend according to the invention consisting of Hytrel® and SEBS in a specific proportion (see Table 2 below). The materials were compared on their ability to capture and transfer a cosmetic formula (a standard mascara) onto artificial eyelashes.

[0076] List of polymers used in examples 1 to 4.

[0077] Polymer blend according to the invention used in examples 1 to 4.

[0078] Each brush is manufactured from a single material (HYTREL® 45D, SEBS 88A, or MXP) by molding, then assembled onto a standard shaft and fitted with a cap. The brush dimensions are identical, with a diameter of 4.4 mm, to ensure comparability.

[0079] The weights of the brushes, including the stem and the cap, are measured empty using a precision analytical balance (accuracy to the milligram).

[0080] The brush is immersed in a fluid cosmetic formula (standard mascara), then wrung out to remove excess product, simulating typical use. The weight after wringing is measured to quantify the initial amount of formula retained on the brush.

[0081] The loaded brush is used to apply the product to a standardized strip of artificial eyelashes. An automated machine ensures uniform application to minimize variability between tests.

[0082] The weight of the brush after transfer (MU, for "Make-Up") is measured, allowing calculation of the amount of product left on the eyelashes.

[0083] The results obtained are summarized in Table 3 below.

[0084] The MXP 35D, a polymer blend according to the invention, exhibits significantly superior performance compared to the individual materials:

[0085] Formula load on brush: MXP reaches 0.319 g, surpassing SEBS (0.279 g) and HYT (0.255 g), indicating better formula retention capacity.

[0086] Load left on the lashes: MXP transfers 0.043 g of product onto the lashes, i.e. 13.48% of the initial load, a result significantly higher than the 8.24% of SEBS and the 5.49% of HYT.

[0087] Relative effectiveness: MXP combines the advantages of the two base polymers, offering good retention on the brush and better release of the product onto the eyelashes.

[0088] These tests demonstrate that the MXP polymer blend, composed of Hytrel® and SEBS, offers optimal performance for cosmetic application. It combines the chemical resistance and flexibility of Hytrel® with the adhesive and gentle properties of SEBS, thus improving both the product load captured by the brush and its efficient transfer to the eyelashes.

[0089] Example 2: Tensile Tests

[0090] To evaluate the mechanical resistance of polymers used in the manufacture of cosmetic brushes, tensile tests were performed on VC0037 brushes from SIMP®, a widely distributed catalog model sold to makeup brands. Four materials were tested: Hytrel® 45D (HYT 45D), SEBS 88A, and two compositions of the mixture according to the invention: MXP 35D and MXP 35D bis, which differ in their proportions from Hytrel and SEBS (see example 1 - table 2).

[0091] The brushes are made by integral molding in a single material (HYT, SEBS, MXP 35D or MXP 35D bis) and are fixed on a standard metal rod.

[0092] Each brush is subjected to a tensile test in a standardized tensile testing machine. The maximum force (F max) exerted before breakage or irreversible deformation is measured in Newtons (N).

[0093] Five separate tests are carried out for each material in order to obtain a representative average of mechanical performance.

[0094] The results obtained are summarized in Table 4 below:

[0095] HYTREL45D: This material has the highest mechanical resistance with an average force of 113.2 N. This reflects excellent robustness, but at the expense of flexibility.

[0096] SEBS 88A: With an average tensile strength of 56.1 N, SEBS exhibits low mechanical resistance, confirming its role as a more flexible but less robust material. 35D: The mixture according to the invention, in its first composition, exhibits an average tensile strength of 66.9 N. This result demonstrates a balanced compromise between robustness and flexibility.

[0097] MXP 35D bis: The second composition of the mixture (different Shore hardness) achieves an average force of 72.8 N, indicating slightly higher mechanical resistance, while retaining a flexibility suitable for cosmetic use.

[0098] The results show that the MXP 35D and MXP 35D bis compositions according to the invention offer intermediate performance between the two reference materials. They combine sufficient mechanical strength for cosmetic use with flexibility and a soft feel. The MXP 35D bis variant, with its slightly increased mechanical strength, could be preferred for applications requiring additional robustness without compromising other functional properties. These results confirm the suitability of polymer blends for providing customized properties tailored to the specific needs of cosmetic brushes.

[0099] Example 3: Visual comparison of cosmetic brushes

[0100] To evaluate the effectiveness of the polymers used in the manufacture of cosmetic brushes, a visual comparison of cosmetic brushes made from different materials was conducted in three distinct states: without formula, with formula before application, and with formula after application. The three materials tested were HYT 45D, SEBS 88A, and MXP 35D, the latter being the polymer blend according to the invention (see Example 1 - Tables 1 & 2).

[0101] The results of these tests are shown in Figure 10.

[0102] First row HYTREL 45D - Without formula: The HYT 45D brush shows a clear and rigid structure, with well-defined bristles. - With formula before application: The brush seems well loaded with cosmetic product, with a homogeneous distribution on the bristles. - With formula after application: After application, the brush retains some of the product, but significant traces remain between the bristles.

[0103] Second row SEBS 88A - Without formula: The SEBS 88A brush also appears clean, but the bristles seem softer. - With formula before application: The brush is loaded with formula, but areas of thicker product are visible, suggesting partial adhesion. - With formula after application: After use, the brush shows an uneven deposit of the formula, suggesting a less effective distribution on the eyelashes.

[0104] Third row MXP 35D (invention) - Without formula: The MXP 35D brush has defined bristles, similar to those in HYT 45D. - With formula before application: The brush shows excellent load capacity, with even distribution of the formula on the bristles. - With formula after application: After application, the brush retains less product than others, indicating better application to the lashes and optimization of formula use.

[0105] The comparison highlights the superior performance of the MXP 35D material according to the invention. This material combines high load-bearing capacity with improved product deposition on the eyelashes, while significantly reducing residual charge on the applicator. These results confirm the advantages of polymer blends for the efficient and homogeneous application of cosmetic formulas.

[0106] Example 4: Visual comparison of makeup application

[0107] To evaluate the effectiveness of the polymers used in the manufacture of cosmetic brushes, a visual comparison of makeup application on human eyelashes under four different conditions was conducted: without makeup, and after application of makeup using brushes made of three distinct materials (HYTREL 45D, SEBS 88A, and MXP 35D (invention)) (see Example 1 - Tables 1 & 2). These images allow visualization of the effects of each brush on the final appearance of the eyelashes.

[0108] The results of these tests are shown in Figure 11.

[0109] First image: Without makeup. This reference image shows natural eyelashes, without any product applied. The eyelashes appear uncurled, lacking volume and definition.

[0110] Second image: HYT 45D. After applying makeup with a HYT 45D brush, the lashes appear slightly thicker and better defined compared to their unmade-up state. However, volume and curl remain limited, indicating the brush's moderate application capacity.

[0111] Third image: SEBS 88A. With the SEBS 88A brush, the lashes have more volume than with HYT 45D. However, the definition of the lashes Individual lashes are less marked, and some clusters of lashes are visible, suggesting a less uniform application.

[0112] Fourth image: MXP 35D (invention). After using the MXP 35D brush, lashes appear noticeably fuller, more defined, and curled compared to other materials. Lash separation is optimized, providing a seamless finish while maximizing makeup intensity and coverage.

[0113] This example highlights the superior performance of the brush made of MXP 35D, according to the invention. It allows for optimal makeup application, combining volume, definition, and homogeneity, surpassing the results obtained with the other materials studied (HYT 45D and SEBS 88A).

Claims

Demands 1. Applicator device intended for the application of a fluid or paste-like product onto keratin fibers, comprising an application member obtained at least partially by molding or by adding material from a mixture of polymers comprising at least two different types of polymers, said types of polymers being selected from TPE-E (thermoplastic elastomers based on copolyesters), TPE-C (thermoplastic elastomers based on crystalline copolymers), TPE-S (thermoplastic elastomers based on styrene), TPE-PA (thermoplastic elastomers based on polyamides), PE (polyethylene), LDPE (low-density polyethylene), LLDPE (linear low-density polyethylene), TPO (thermoplastic polyolefins), TPV (thermoplastic vulcanized materials), TPU (thermoplastic polyurethane), PDMS (polydimethylsiloxane) and PU (polyurethane).

2. Device according to claim 1, characterized in that the polymer mixture comprises: - between 5% and 95%, preferably between 20% and 80%, more preferably between 30% and 70%, and even more preferably between 40% and 60% by weight of a first polymer, and - between 5% and 95%, preferably between 20% and 80%, more preferably between 30% and 70%, even more preferably between 40% and 60% by weight of a second polymer of a different type.

3. Device according to any one of claims 1 to 2, characterized in that the first polymer is a TPE-C or a TPE-E and the second polymer is selected from a TPE-S, TPU or TPE-PA.

4. Device according to any one of claims 1 to 3, characterized in that the mixture also comprises from 1% to 30% by weight of a third polymer selected from PDMS, PE or TPO.

5. Device according to any one of claims 1 to 4, characterized in that the application member comprises an elongated central core extending along a longitudinal axis, and a plurality of pins formed of a moldable material from the mixture.

6. Device according to any one of claims 1 to 5, characterized in that at least part, preferably all, of the bumps are made in the polymer mixture according to the invention, preferably unitarily with the core, preferably in the same material.

7. A device according to any one of claims 1 to 6, characterized in that the polymer blend has a hardness greater than or equal to 20 Shore A, preferably greater than or equal to 40 Shore A, or even greater than or equal to 60 Shore A 8. Device according to any one of claims 1 to 7, characterized in that the application member has a tensile strength between 2 MPa and 100 MPa, preferably between 10 MPa and 60 MPa and / or an elongation at break greater than 200%, preferably 500%.

9. Polymer mixture as defined in any one of claims 1 to 8 for use in the manufacture of an applicator device for the application of a fluid or paste-like product onto keratin fibers.

10. A method for manufacturing an applicator device for applying a fluid or paste-like product to keratin fibers or the epidermis, characterized in that it comprises the following steps: a) Preparing a mixture comprising at least two polymers of different types, said types of polymers being selected from TPE-E (thermoplastic elastomers based on copolyesters), TPE-C (thermoplastic elastomers based on crystalline copolymers), TPE-S (thermoplastic elastomers based on styrene), TPE-PA (thermoplastic elastomers based on polyamides), PE (polyethylene), LDPE (low-density polyethylene), LLDPE (linear low-density polyethylene), TPO (thermoplastic polyolefins), TPV (thermoplastic vulcanized materials), TPU (thermoplastic polyurethane), PDMS (polydimethylsiloxane) and PU (polyurethane); b) Heat the mixture to reach a temperature that allows it to be processed by molding or injection;c) Inject or mold the mixture into a mold configured to form the application element of the device; d) Cool and demold the applicator device.

Images