SHEATH FOR AN APPLICATION RECIPE FOR A COSMETIC PRODUCT GRAPE

Abstract

The invention relates to a sheath (40) for a cosmetic product application device (10), in particular for a cosmetic product applicator (12), the sheath (40) having a tubular wall (41) internally comprising at least one helical groove (42, 44), the sheath (40) being designed to internally receive a guide (14) having a slot (22, 24), and each helical groove (42, 44) being designed to receive a lug (32) of a cup (30) of the device (10), the sheath (40) being made of a plastic material selected from the polyester family, characterized in that the selected plastic material has a deflection temperature (T1), determined according to method A, greater than or equal to 80°C and a deflection temperature (T2), determined according to method B, greater than or equal to 80°C. Figure for the abstract: Figure 4

Description

Title of the invention: SHEATH FOR A COSMETIC PRODUCT APPLICATION RECIPE Technical field of the invention

[0001] The invention relates to a sheath for a cosmetic product application device, in particular for a cosmetic product grape, the sheath having a tubular wall having internally at least one helical groove, the sheath being intended to internally receive a guide having a slot, and each helical groove being intended to receive a lug of a cup of the device, the sheath being made of a plastic material which is selected from the family of polyesters. Technical background

[0002] In a conventional manner, devices for applying a cosmetic product, in particular a lipstick bullet, include a mechanism for moving the cosmetic product between a retracted position and an application position in which the cosmetic product is likely to be applied by rubbing.

[0003] The actuation of the mechanism is generally controlled manually by applying a rotational movement to a sheath of the device relative to a guide to cause the axial displacement of a cup containing the cosmetic product.

[0004] This type of mechanism generally comprises at least one casing, also called a cap, fitted onto the sheath that participates in the movement of the cosmetic product. The casing is a visible, aesthetically pleasing part.

[0005] Conventionally, the casing and the sheath are made in the form of two separate parts for which the material can be freely chosen. In such a design, the two parts must be rigidly connected to each other, both axially and rotationally.

[0006] Typically a metallic material, such as anodized aluminum, is chosen for the casing and a plastic material is chosen for the sheath of the mechanism.

[0007] It is known to glue the casing onto the sheath. However, this solution is not satisfactory because the glue can alter the appearance of the device. Furthermore, it adds an extra step during the assembly of the device.

[0008] It has already been proposed to axially fix the casing around the sheath by the cooperation of complementary shapes. Thus, by folding a lower edge of the casing inwards to form a shoulder received axially against an annular ridge formed at the bottom of the sheath. In addition, to secure the casing against rotation to the sheath, axial grooves or striations are provided on the inner face of The casing cooperates with complementary grooves or striations made on the outer face of the sheath. However, obtaining these shapes involves costly operations that lengthen the manufacturing time of a device.

[0009] It has also been proposed to press-fit the aluminum casing around the sheath with a tight fit. Such an assembly is indeed quick and does not require additional and costly operations.

[0010] To enable such an assembly, the plastic material forming the sheath must possess properties that allow it to withstand various mechanical stresses under different operating conditions. In particular, the material must exhibit good resistance to aging at different climatic temperatures. Furthermore, the selected material must have injection properties that allow the sheath to be produced by injection molding, despite the fact that the sheath has a wall of heterogeneous thickness with an extremely small minimum value. Until very recently, only polyoxymethylene, also known as POM, was used for this purpose because it possesses the required properties for both molding the sheath and for its mechanical resistance under various climates. However, this material can no longer be used for regulatory reasons, particularly environmental ones. Summary of the invention

[0011] The invention proposes a sheath for a cosmetic product application device, in particular for a cosmetic product applicator, the sheath having a tubular wall internally comprising at least one helical groove, the sheath being intended to internally receive a guide comprising a slot, and each helical groove being intended to receive a lug of a cup of the device, the sheath being made of a plastic material which is selected from the polyester family,

[0012] characterized in that the selected plastic material has a load deflection temperature, determined according to method A of ISO 75-2:2003, greater than or equal to 80°C and a load deflection temperature, determined according to method B of ISO 75-2:2003, greater than or equal to 80°C.

[0013] According to another aspect of the invention, the plastic material comprises at least 10% glass fiber.

[0014] According to another aspect of the invention, the plastic material is formed by a copolyester.

[0015] According to another aspect of the invention, the plastic material is a polybutylene terephthalate.

[0016] According to another aspect of the invention, the sheath is made in one piece by molding the plastic material.

[0017] According to another aspect of the invention, the wall of the sheath has a nominal thickness of between 0.6 and 0.8mm.

[0018] According to another aspect of the invention, the helical groove is formed directly during molding by reducing the nominal wall thickness.

[0019] According to another aspect of the invention, the wall thickness at the level of at least one helical groove represents between 30 and 50% of the nominal wall thickness.

[0020] According to another aspect of the invention, Tritan is excluded from the selection.

[0021] The invention also relates to a device for applying a cosmetic product, in particular a cosmetic product applicator, comprising:

[0022] - a cup intended to receive the grape and comprising at least one radial lug;

[0023] - a guide comprising a tubular body in which the cup is slidably mounted axially, the guide comprising at least one slot which is traversed by at least one associated lug of the cup;

[0024] - a tubular sheath in which the body is mounted for rotation, the sheath internally including at least one receiving groove for at least one lug of the cup, the rotation of the guide relative to the sheath causing an axial movement of the cup between an extreme deployed position and an extreme retracted position;

[0025] - a tubular sleeve into which the sheath is forced into place;

[0026] characterized in that the sheath is made according to the teachings of the invention.

[0027] According to another aspect of the device made according to the teachings of the invention, the sleeve has an inner face which is in contact with the sheath and which is smooth.

[0028] According to another aspect of the device implemented according to the teachings of the invention, the sheath has an external face that is in contact with the jacket and is smooth. Brief description of the figures

[0029] Other features and advantages of the invention will become apparent during the reading of the detailed description which follows, for the understanding of which reference will be made to the attached drawings which are briefly described below.

[0030] Fig. 1 is a perspective view which represents a device made according to the teachings of the invention in a mounted position.

[0031] Fig. 2 is an exploded perspective view of the device of Fig. 1 which comprises a guide, a cup, a sheath and a sleeve.

[0032] Fig. 3 is a view similar to that of Fig. 2 in which the elements are in section along the section plane 3-3 of Fig. 2.

[0033] Fig. 4 is a cross-sectional view along section plane 4-4 of Fig. 1, the cup occupying its hidden extreme position.

[0034] Fig. 5 is a view similar to that of Fig. 4 in which the cupule occupies its extreme position deployed. Detailed description of the invention

[0035] By convention, the "axial" direction corresponds in the figures to that of the main axis A of the device (also called mechanism) intended to be mounted on an actuation base of a cosmetic product application device, such as a cosmetic product bullet, in particular a lipstick bullet, and the "radial" direction is directed orthogonally to the axial direction by radiating from the main axis.

[0036] In the detailed description of the figures that follows, the terms "upper" and "lower" or "top" and "bottom" will be used without limitation in reference to the axial direction, the upper part of the device corresponding to that through which the grape of cosmetic product exits the device for application.

[0037] Similarly, the terms "outside or external" and "inside or internal" are used with reference to the radial direction, an outside element being radially further away from axis A than an inside element.

[0038] The figures illustrate a device 10 intended to be mounted on an actuation base of a cosmetic product application receptacle.

[0039] Preferably, the cosmetic product (represented in dotted lines in figures 4 and 5) is a cosmetic product 12 grape and, more particularly, the cosmetic product 12 grape is a lipstick intended to be applied by rubbing, alternatively a lip balm.

[0040] The device 10 is designed to expel the cosmetic product by at least one rotational movement.

[0041] The device 10 has an axis A, called the principal axis.

[0042] The device 10 includes at least one guide 14. The guide 14 is particularly visible in figures 2 and 3.

[0043] The guide 14 mainly comprises a tubular body 16 which extends axially from a base 18 forming the lower end of the guide 14 to an upper outlet opening 20 intended to be traversed by the cosmetic product grape 12.

[0044] The external surface of the base 18 is for example provided with grooves to facilitate its handling when using the device 10 or its coupling with the base where applicable.

[0045] Preferably, the guide 14 comprises at least one slot passing radially through the wall of the body 16. Each slot forms a slide. The guide 14 here comprises a first slot 22 and a second slot 24 passing radially through the wall of the body 16. Slots 22, 24 are arranged diametrically opposite each other.

[0046] The slots 22, 24 extend axially within the body 16 of the guide 14. The first slot 22 is axially closed at its upper end, while the second slot 24 is open. The slots 22, 24 are closed at their lower end, which is located on the side of the base 18.

[0047] The slots 22, 24 each have straight and parallel edges. The first slot 22 has at one of its axial ends an upper notch 26a and at the other of its ends a lower notch 28a, said notches 26a, 28b extending circumferentially.

[0048] In both embodiments, the second slot 24 also has upper and lower notches 26b, 28b.

[0049] In conventional systems, the notches 26a, 26b, 28a, 28b are intended to form means for locking the end of travel of a cup 30.

[0050] The device 10 includes the cup 30 which receives the grape 12 of cosmetic product.

[0051] The cup 30 is intended to be mounted to slide axially in the guide 14, between an extreme retracted position, as shown in [Fig.4], and an extreme deployed position, as shown in [Fig.5].

[0052] The extreme retracted position corresponds to a position in which the grape 12 is inside the device 10 for protection and storage and the cup 30 is in the lower end-of-stroke position as illustrated in [Fig.4].

[0053] The extreme deployed position corresponds to a position in which the grape 12 is deployed axially upwards so that its free end extends out of the device 10 through the opening 20 and the cup 30 is in the upper end-of-stroke position as illustrated in [Fig.5].

[0054] The cup 30 can also occupy intermediate positions between its two extreme retracted and deployed positions, called intermediate application positions.

[0055] The cup 30 has at least one lug 32, preferably two lugs 32. Each lug 32 protrudes radially outwards, said lugs 32 being each engaged in one of the slots 22, 24 of the guide 14 and passing through them to extend radially outwards beyond the external cylindrical surface of the body 16 of the guide 14.

[0056] The cup 30 comprises a cylindrical wall 34 extending axially. The wall 34 defines a recess 36 which receives the lower part of the grape 12. The recess 36 is open upwards by an inlet 33. The inner face of the cylindrical wall 34 is provided with ribs 38 which are intended to fix the grape 12 firmly in the recess 36.

[0057] The device 10 includes a sheath 40. As represented here, the sheath 40 has a tubular wall 41 with main axis A.

[0058] Preferably, the sheath 40 has internally at least one groove receiving The free end of a lug 32 associated with the cup 30. The sheath 40 here has two diametrically opposed grooves 42, 44, with which the free ends of the lugs 32 of the cup 30 cooperate during operation. The wall 41 of the sheath 40 has an internal cylindrical face 46 provided with said grooves 42, 44. The grooves 42, 44 are helical in shape. The wall 41 of the sheath 40 also has a smooth external cylindrical face 47.

[0059] The wall 41 of the sheath has a determined nominal thickness "el", which is for example between 0.6 mm and 0.8 mm, for example equal to 0.7 mm. The thickness "el" is measured between the inner face 46 and the smooth outer face 47 of the sheath 40, as shown in Figures 3 to 5.

[0060] In addition, since the grooves 42, 44 are made in the thickness of the wall 41, the thickness "e2" of the wall 41 of the sheath 40 is reduced at the level of the grooves 42, 44 compared to the nominal thickness "el". The thickness "e2" is measured radially between a bottom 49 of the groove 42, 44 and the smooth external cylindrical face 47 of the sheath 40. Thus, the thickness "e2" of the wall 41 at the grooves 42, 44 represents, for example, between 30% and 50% of the nominal thickness "el" of the sheath 40. For example, the thickness "e2" of the wall 41 at the grooves 42, 44 is between 0.20 mm and 0.40 mm, preferably between 0.25 mm and 0.35 mm, for example equal to 0.28 mm.

[0061] The sheath 40 respectively comprises an upper edge 50 located at its upper axial end and a lower edge 52 located at its lower axial end, said edges 50 and 52 being circumferentially continuous.

[0062] The sheath 40 is intended to be mounted by snapping onto the guide 14 to obtain, after assembly, the devices 10 represented in particular in figures 1, 4 and 5.

[0063] The guide 14 is mounted for rotation within the sleeve 40 around the main axis "A". The guide 14 is thus received concentrically inside the sleeve 40. For this purpose, the body 16 of the guide 14 has an external diameter substantially equal to the internal diameter of the sleeve 40.

[0064] In the embodiment shown in Figures 4 and 5, the elastic snap-fit ​​is achieved, by way of example, by an annular bead 54 projecting from a lower portion of the inner face 46 of the sheath 40. A collar 56 projects radially from the outer face of the body 16, near the base 18. The collar 56 is intended to snap elastically into place above the bead 54 of the sheath 40 when the body 16 of the guide 14 is inserted axially, from bottom to top, through a lower opening in the sheath 40. The collar 56 is then axially butted against a shoulder face 57 of the sheath 40.

[0065] The collar 56 is formed in a lower portion 60 of the sheath 40 which extends downwards from the tubular wall 41. The lower portion 60 has a external diameter slightly greater than that of the external face 47 of the wall 41 of the sheath 40. This lower portion 60 is linked to the external face 47 by a shoulder face 62 turned axially upwards.

[0066] The slot 22 of the guide 14 is here opened upwards by means of a cutout 58 which opens into the upper end edge of the body 16 which delimits the opening 20. Thanks to this cutout 58 the guide 14 can deform radially to facilitate the assembly of the sheath 40 before returning to its initial shape.

[0067] In such a device 10, rotating the guide 14 via its base 18 relative to the sleeve 40 causes an axial movement of the cup 30, more precisely an upward or downward movement of the cup 30 depending on the direction of rotation. When the cup 30 is in its fully extended position, an upper portion of the cup 30 extends axially out of the sleeve 40.

[0068] The cosmetic product grape 12 moves axially with the cup 30 between the extreme deployed position and the extreme retracted position.

[0069] For aesthetic reasons, it is known to equip the duct 40 with a tubular sleeve 64, sometimes called a sleeve or casing, or, according to its English name, an "A-shell". The sleeve 64 has a smooth internal cylindrical face 66 which is intended to be in contact with the smooth external cylindrical face 47 of the duct 40. The duct 40 is press-fitted into the sleeve 64. This press fit secures the sleeve 64 to the duct 40 both axially and rotationally about the main axis A.

[0070] Only the lower portion 60 of the sheath 40 remains here outside the sleeve 64. For this purpose, a lower end edge 68 of the sleeve 64 comes into contact with the shoulder face 62.

[0071] The sleeve 64 is generally made of metal, for example aluminum.

[0072] The sleeve 64 has an upper rim 70 which has an annular shape which extends radially inwards above the opening 20 of the guide 14 when the device 10 is mounted, as shown in figures 4 and 5.

[0073] The sheath 40 is made of plastic. For recycling purposes, the sheath 40 is made of a plastic material selected from the polyester family. For example, it is a copolyester.

[0074] However, the plastic material must have properties that allow for press-fit assembly into the sleeve 64, and this assembly must be able to withstand time and various, sometimes extreme, climatic conditions. For example, the assembly of the sleeve 64 onto the sheath 40 is considered sufficiently strong when it resists an axial pull-out force of 50 N after the sheath 40, fitted with its sleeve 64, has been exposed to a climatic cycle, for example, as defined by ISO 4892-3:2016.

[0075] However, it has been observed that certain polyesters, such as polyethylene terephthalate (PET) or polyethylene terephthalate glycol (PETG) in their formulations commonly used for this type of device, do not allow for a sufficiently reliable and durable mounting of the liner 64 by tight fit.

[0076] The invention proposes to select from among the many polyesters, those which meet several conditions.

[0077] A first condition is that the selected plastic material has a heat deflection temperature "Tl" under load (also known by the English acronym HDT meaning "Heat Deflection Temperature"), determined according to method A (load of 1.80 MPa) of ISO 75-2:2013, which is greater than or equal to 80°C.

[0078] A second condition is that the selected plastic material has a load deflection temperature "T2" (HDT), determined according to method B (load of 0.45 MPa) of ISO 75-2:2013, which is greater than or equal to 80°C.

[0079] The load deflection temperature "T1, T2" (HDT) is the temperature at which specimens of the selected plastic material, subjected to the bending action of certain given loads, undergo conventional deformation. This method applies to plastic materials that are rigid at room temperature and three to thirteen millimeters thick.

[0080] The test specimen is placed on two supports 100 mm apart in an oven whose temperature rise is programmed at 2 °C / min. The bending load is applied to the upper part of the sample using a punch. The international standard ISO 75-2:2013, used for characterizing plastics, specifies, for example, loads of 1.80 MPa (method A) or 0.45 MPa (method B).

[0081] By way of non-limiting example, by using these parameters to select suitable polyesters for making such a sheath 40, the inventor was thus able to quickly identify a copolyester marketed under the brand name "ECOZEN Tl 10" by SK Chemicals. This product has a deflection temperature "Tl" obtained according to method A of 81°C and a deflection temperature "T2" obtained according to method B of 97°C. It therefore meets the first two conditions.

[0082] By way of another non-limiting example, the inventor was also able to identify polybutylene terephthalate (PBT) containing 10% glass fiber as having the required properties. This product has a deflection temperature "T1" obtained according to method A of 190°C and a deflection temperature "T2" obtained according to method B of 215°C. It therefore meets the first two conditions.

[0083] In addition, the selected materials must also meet a third condition. They must, in fact, possess the properties necessary to obtain the sheath 40 by molding despite the small thickness "e2" of the wall 41 at the grooves 42, 44. This third condition is verified experimentally by making a mold of the sheath 40 with the material responding positively to the first two conditions.

[0084] Thus, the ECOZEN Tl 10 material and the glass fiber-reinforced PBT could be successfully used to mold a sheath 40 with the required dimensions.

[0085] These two materials are given by way of non-limiting example; any other plastic material from the polyester family fulfilling the three conditions defined above makes it possible to obtain a forceful bond between the jacket 64 and a sheath 40 made of such a material.

[0086] On the other hand, a plastic material such as that marketed under the brand name Tritan by the company Eastman Chemical, although it has "T1, T2" deflection temperatures fulfilling the first two conditions, does not have the injectability properties required for molding the sheath 40. This material is therefore excluded from the selection because it does not fulfill the last condition.

[0087] Advantageously, the guide 14, the cup 30 and the sheath 40 are advantageously made of plastic material.

[0088] Preferably, the guide 14, the cup 30 and the sheath 40 are made of the same plastic material to facilitate recycling.

Claims

Claims

1. Sheath (40) for a device (10) for applying a cosmetic product, in particular a grape (12) of cosmetic product, the sheath (40) having a tubular wall (41) internally comprising at least one helical groove (42, 44), the sheath (40) being intended to internally receive a guide (14) comprising a slot (22, 24), and each helical groove (42, 44) being intended to receive a lug (32) of a cup (30) of the device (10), the sheath (40) being made of a plastic material which is selected from the family of polyesters, characterized in that the selected plastic material has a deflection temperature (T1) under load, determined according to method A (load of 1.80 MPa) of standard ISO 75-2:2003, greater than or equal to 80°C and a deflection temperature (T2) under load, determined according to method B (load of 0.45 MPa) of standard ISO 75-2:2003, greater than or equal to 80°C.

2. Sheath (40) according to any one of the preceding claims, characterized in that the plastic material comprises at least 10% glass fiber.

3. Sheath (40) according to the preceding claim, characterized in that the plastic material is formed by a copolyester.

4. Sheath (40) according to claim 2, characterized in that the plastic material is a polybutylene terephthalate (PBT).

5. Sheath (40) according to any one of the preceding claims, characterized in that it is made in a single piece by molding the plastic material.

6. Sheath (40) according to any one of the preceding claims, characterized in that the wall (41) of the sheath (40) has a nominal thickness (el) of between 0.6 and 0.8 mm.

7. Sheath (40) according to the preceding claim, characterized in that the helical groove (42, 44) is formed directly during molding by reducing the nominal thickness (el) of the wall (41).

8. Sheath (40) according to the preceding claim, characterized in that the thickness (e2) of the wall (41) at the level of the at least one helical groove (42, 44) represents between 30 and 50% of the nominal thickness (el) of the wall (41).

9. Sheath (40) according to any one of the preceding claims, characterized in that Tritan is excluded from the selection.

10. Device (10) for applying a cosmetic product, in particular a stick (12) of cosmetic product, comprising: - a cup (30) intended to receive the stick (12) and comprising at least one radial lug (32); - a guide (14) comprising a tubular body (16) in which the cup (30) is mounted to slide axially, the guide (14) comprising at least one slot (22, 24) which is crossed by the at least one associated lug (32) of the cup (30); - a tubular sheath (40) in which the body (16) is rotatably mounted, the sheath (40) internally comprising at least one groove (42, 44) for receiving the at least one lug (32) of the cup (30), the rotation of the guide (14) relative to the sheath (40) causing an axial movement of the cup (30) between an extreme deployed position and an extreme retracted position; - a tubular jacket (64) in which the sheath (40) is force-fitted;characterized in that the sheath (40) is made according to any one of the preceding claims.;

11. Device (10) according to the preceding claim, characterized in that the jacket (64) has an internal face (66) which is in contact with the sheath (40) and which is smooth.

12. Device (10) according to any one of claims 10 or 11, characterized in that the sheath (40) has an external face (47) which is in contact with the jacket (64) and which is smooth.

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