Cap for cosmetic applicator

Abstract

To provide a cap for cosmetic applicator or the like which improves crack resistance and is unlikely to fall when a cosmetic is adhered to an inner cap in a cap composed of three components.SOLUTION: In a cap for cosmetic applicator provided with a cylindrical outer cap, a synthetic resin inner cap located on an inner surface side of the outer cap, and a spring pressing the inner cap to the opening side of the outer cap, a back surface of a spring receiving surface of the inner cap is formed into a continuing linear shape and a pressing force P and a connection part volume V satisfy a relationship of V / P=27 to 39 in the case of a connection part volume V(mm3) relative to a back surface from the spring receiving surface relative to a pressing force P(MPa) pressing when a flange part of the inner cap of the spring is fitted to a shaft cylinder.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cap for a cosmetic applicator that will not break even when a cosmetic is attached to it and dries. [Background technology]

[0002] Cosmetic tools that contain a low-viscosity cosmetic liquid in a cosmetic tank (storage section) are fitted with a cap (cosmetic tool cap) to protect the application section from drying out when not in use. Patent documents 1 to 4 disclose that this cap is made up of three parts: an inner cap on the inner tube, an outer cap on the outer tube, and a spring that allows the inner cap to slide inside the outer cap to prevent an increase in the internal pressure of the ink tank when the cap is opened and closed.

[0003] In this type of cap, the inner cap and the outer cap are prevented from coming off by fitting a flange of the inner cap into a protrusion on the inner wall of the outer cap. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-146366 [Patent Document 2] Japanese Patent Publication No. 2022-178890 [Patent Document 3] Japanese Patent Publication No. 2020-116105 [Patent Document 4] Japanese Utility Model Application Publication No. 6-66514 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when users try to close the cap after use, cosmetics often adhere to the inner wall of the inner cap. When the cosmetics dry, the inner cap and the barrel to which the cap is attached stick together. When the user tries to open the cap in this state, the inner cap, which is stuck to the barrel, may come off the outer cap.

[0006] The present invention aims to provide a cap for cosmetics, etc., which is made up of three parts and has improved crack resistance, and which does not fall off from the outer cap even if cosmetics adhere to the inner cap. [Means for solving the problem]

[0007] The present invention relates to a cap for a cosmetic applicator, which comprises a cylindrical outer cap, an inner cap made of synthetic resin and positioned on the inner surface of the outer cap, and a spring that presses the inner cap toward the opening of the outer cap. The back surface of the spring receiving surface of the inner cap is formed into a continuous linear shape, and the connecting portion volume V (mm ) from the spring receiving surface to the back surface is set to a value corresponding to the pressing force P (MPa) that the spring applies when attaching the flange of the inner cap to the barrel. 3 ), the pressing force P and the connection portion volume V satisfy the relationship V / P=27 to 39. More preferably, V / P=30 to 35.

[0008] In the present invention, it is preferable that the inner cap has a side surface and a flange portion, the flange portion having a front surface located on the leading barrel side and a back surface located on the rear barrel side, the front surface having a spring receiving surface that receives one end of the spring, and the back surface having a continuous curved surface that is connected to the side surface.

[0009] In the present invention, it is preferable that the flange portion has a recess on the front surface.

[0010] The present invention also provides a cosmetic applicator comprising any one of the caps of the cosmetic applicators described above. [Effects of the Invention]

[0011] The invention described above improves crack resistance and ensures the quality of the cap for a long period of time. It has the excellent effect of providing a cosmetic cap in which the flange of the inner cap does not break over time and there is no risk of the inner cap falling off even if cosmetics adhere to the inner cap. [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are overall views showing a cosmetic applicator according to a first embodiment of the present invention in a capped state, where (a) is an external view and (b) is a longitudinal cross-sectional view. [Figure 2] 1A and 1B are overall views showing a state in which the cap is removed of a cosmetic applicator according to a first embodiment, where (a) is an external view and (b) is a longitudinal cross-sectional view. [Figure 3] 1A and 1B are explanatory diagrams showing the component configuration of the cap according to the first embodiment, in which (a) is a view from the front, (b) is a perspective view from the rear, (c) is a view from the rear, and (d) is a vertical cross-sectional view. [Figure 4] FIG. 2 is an exploded perspective view of the cap according to the first embodiment. [Figure 5] 1A and 1B are part diagrams of an outer cap according to a first embodiment, in which (a) is a perspective view from the front, (b) is a view from the front, (c) is a side view, (d) is a longitudinal cross-sectional view, (e) is a perspective view from the rear, and (f) is a view from the rear. [Figure 6] Component diagrams of the inner cap according to the first embodiment, where (a) is a perspective view from the front, (b) is a view from the front, (c) is a side view, (d) is a longitudinal cross-sectional view, (e) is a perspective view from the rear, and (f) is a view from the rear. [Figure 7] 1A and 1B are component diagrams of a spring according to a first embodiment, in which (a) is a side view and (b) is a perspective view. [Figure 8]10 is a cross-sectional view illustrating a state in which the inner cap is press-fitted into the outer cap. FIG. [Figure 9] Component diagrams of an inner cap according to a second embodiment of the present invention, where (a) is a perspective view from the front, (b) is a view from the front, (c) is a side view, (d) is a vertical cross-sectional view, (e) is a perspective view from the rear, and (f) is a view from the rear. [Figure 10] 1A and 1B are explanatory side views comparing inner caps of a comparative example and an embodiment, where (a) shows the comparative example and (b) shows the embodiment. [Figure 11] 1A and 1B are explanatory views of inner caps of a comparative example and an example, in which (a) and (b) are a front view and a side view of the comparative example, (c) and (d) are a front view and a side view of the first embodiment, and (e) and (f) are a front view and a side view of the second embodiment. [Figure 12] 10A and 10B are reference diagrams showing the molding state of an inner cap with and without a recess. [Figure 13] FIG. 10 is an explanatory diagram showing a state in which a drop impact resistance test is performed using a hole gauge and a weight on the inner caps according to the comparative example and the example. [Figure 14] 10 is an explanatory diagram of the spring receiving surface area S of the flange portion of the inner cap. FIG. [Figure 15] FIG. 10 is an explanatory diagram of the connection volume V of the flange portion of the inner cap. [Figure 16] 1A and 1B are explanatory diagrams of drop impact resistance tests for Examples 1 to 11 and Comparative Examples 1 to 4, illustrating the effects of the present invention, where (a) is the test results and (b) is an explanatory diagram of the spring specifications. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described with reference to the drawings.

[0014] [1. First embodiment] 1.1 Configuration of the first embodiment A cosmetic applicator and its cap according to a first embodiment of the present invention will be described.

[0015] As shown in Figures 1 and 2, the cap 24 of the cosmetic applicator (hereinafter also referred to simply as the applicator) according to this embodiment comprises a cylindrical outer cap 24o having an opening (opening) 24b, an inner cap 24i arranged on the inner surface of the outer cap 24o, and a spring 24s that biases the arranged inner cap 24i towards the opening (opening) 24o of the outer cap 24o. As shown in FIGS. 3 and 6, inner cap 24i has an outer peripheral surface (side surface) 24i5 and a flange (brim) 24i1. Flange 24i1 has a front surface 24i2 located on the front barrel 12 side and a back surface 24i3 located on the rear barrel 20 side. Front surface 24i2 has a spring receiving surface 24i22 that receives one end of spring 24s. Back surface 24i3 has a continuous curved surface 24i4 that is connected to outer peripheral surface (side surface) 24i5. The force with which spring 24s presses against spring receiving surface 24i22 is defined as pressing force P (MPa). The connection volume, which is the volume of the region of connection portion 24v between spring receiving surface 24i22 and back surface 24i3 in flange 24i1, is defined as V (mm 3 ) V / P = 27 to 39 is satisfied.

[0016] The cosmetic applicator has a barrel tube in which a cylindrical rear barrel 20 with a closed rear end is fitted onto the rear part of a tapered cylindrical front barrel 12 to form an integrated barrel.

[0017] Applicator part 10 is provided with its tip protruding and exposed in opening 12c at the front end of front barrel 12. The applicator has a removable cap 24 attached to the outer periphery of front barrel 12 to cover applicator part 10 when not in use.

[0018] Rear barrel 20 fits onto the outer periphery of the rear part inside front barrel 12. Flange 12a expands in diameter on the outer periphery of front barrel 12, and rear barrel 20 abuts against the rear side surface of flange 12a. Front barrel 12 and rear barrel 20 form the outer periphery of the barrel tube. Cap 24 abuts against the front side surface of flange 12a.

[0019] The cap 24 is configured by housing an inner cap 24i and a spring 24s inside an outer cap 24o that is fitted with an exterior part 24d. The exterior part 24d is attached to the outer periphery of the cap 24 for the purpose of appearance design and protection against scratches.

[0020] The outer cap 24o has an annular inward protrusion 24o1 formed on its inner peripheral surface at the axial center thereof, protruding in the inner diameter direction. The inner cap 24i has an annular flange 24i1 formed on its outer peripheral surface at its front end, protruding in the outer diameter direction. As will be described later, when the inner cap 24i is attached to the outer cap 24o, the flange 24i1 rides over the inward protrusion 24o1 to fit (override-fit). The spring 24s is a coil spring formed by spirally winding an elastic wire. The spring 24s is roughly hand drum-shaped, with openings at the front and rear. The spring 24s is disposed inside the outer cap 24o, with the front portion of the inner cap 24i inserted into the rear opening. The spring 24s is held between the front side of the flange 24i1 and the inner surface of the top surface 24f of the outer cap 24o.

[0021] A liquid storage section (application liquid tank) 16 that stores a cosmetic product is provided at the rear of the interior of rear barrel 20. A comb-tooth-shaped ink guide section (temporary reservoir) 18 is attached to liquid storage section 16. Comb-tooth-shaped ink guide section 18 is provided in contact with the rear end of applicator section 10. A relay core 14 is provided within comb-tooth-shaped ink guide section 18. Relay core 14 guides the liquid cosmetic product to applicator section 10. The front end of applicator section 10 protrudes and is exposed from opening 12c (see FIG. 2) provided at the tip of front barrel 12. The inner circumferential surface of opening 12c is in contact with the outer periphery of applicator section 10. Within front barrel 12, the tip of relay core 14 is in contact with the inner circumferential surface of the rear end of applicator section 10 to guide the cosmetic product, and comb-tooth-shaped ink guide section 18 guides the application liquid from relay core 14 to applicator section 10 via application liquid guide grooves (slits) 18c, forming an applicator.

[0022] A more specific configuration will now be described.

[0023] 1, the rear end of applicator part 10 is hollow and has flange 10a with an expanded diameter formed on the outside. The tip of applicator part 10 is provided within front barrel 12 so as to protrude from the tip opening of front barrel 12.

[0024] A comb-teeth-shaped ink guide portion 18, which has the function of temporarily storing liquid between multiple leaf elements, is disposed within front barrel 12. Flange 10a is pressed by the tip of comb-teeth-shaped ink guide portion 18 to be fixed within front barrel 12. Relay core 14 within hollow hole 18a of comb-teeth-shaped ink guide portion 18 is structured to guide the liquid cosmetic within liquid storage portion 16 to application portion 10.

[0025] The opening side of the tip of liquid containing section 16 is fixed into the rear part of front barrel 12 by press-fitting or melt-fitting.

[0026] [Comb-shaped ink guide portion 18] As shown in Figures 1 and 2, a hollow hole 18a is formed inside the comb-tooth-shaped ink guide portion 18 along the axial direction from the tip to the rear end, and the relay core 14 is attached inside the hollow hole 18a.

[0027] A plurality of ink leaves 18b are arranged at regular intervals around the outer periphery of the comb-shaped ink guide portion 18. The liquid is temporarily stored by the capillary force generated between the ink leaves 18b, and the function of air replacement is exhibited.

[0028] Slits 18c are formed so as to cut the leaves 18b in the vertical direction (axial direction). The comb-shaped ink guide portion 18 is configured so that the liquid cosmetic can flow in and out between the leaves 18b via the slits 18c.

[0029] Furthermore, a rib may be formed inside the hollow hole 18a, and the relay core 14 may be supported by the rib.

[0030] Comb-shaped ink guide portion 18 is attached inside front barrel 12. At the rear end of comb-shaped ink guide portion 18, hollow hole 18a and slit 18c face the opening at the front of liquid containing portion 16.

[0031] The rear end face (rear end) of the relay core 14 mounted in the hollow hole 18a of the comb-tooth ink guide section 18 is exposed to the front opening of the liquid storage section 16, and the relay core 14 guides the liquid (liquid cosmetic) in the liquid storage section 16 forward (towards the application section 10).

[0032] The tip of the comb-tooth-shaped ink guide portion 18 is cup-shaped, and the cup tip fits into and is positioned in a stepped portion 12d formed inside the front barrel 12. The cup-shaped tip of the comb-tooth-shaped ink guide portion 18 presses against the rear end of the applicator portion 10 (the rear end surface of the flange 10a). The tip of the relay core 14 inside the comb-tooth-shaped ink guide portion 18 is inserted into the rear end space of the applicator portion 10. The rear end of the comb-tooth-shaped ink guide portion 18 is exposed toward the liquid storage portion 16, and when the internal pressure of the liquid storage portion 16 increases due to changes in air pressure or temperature, the application liquid in the liquid storage portion 16 passes through the slits 18c and is reserved between the leaves 18b of the comb-tooth-shaped ink guide portion 18. When the internal pressure of the liquid storage portion 16 decreases due to consumption of the application liquid, the application liquid reserved in the comb-tooth-shaped ink guide portion 18 returns to the liquid storage portion 16 via the slits 18c. Front barrel 12 is formed with ventilation holes 12b that allow ventilation between the inside and outside of comb-tooth shaped ink guide portion 18 for gas-liquid replacement.

[0033] Outside air circulates through vent hole 12b into the interior of front barrel 12, and then through sheets 18b and slits 18c on the outer periphery of comb-tooth-shaped ink guide portion 18 housed within front barrel 12. Therefore, even if there is a fluctuation in the internal pressure of liquid containing portion 16, this is alleviated by the ventilation within front barrel 12, preventing the coating liquid from spraying out from coating portion 10 and the like, running out of coating liquid, and the like.

[0034] [Liquid storage section 16] As shown in Figures 1 and 2, the liquid storage section 16 is a generally cylindrical container (tank) with an opening at the front and a closed rear end, and stores the application liquid inside. The rear of the comb-tooth ink guide section 18 mounted in the front barrel 12 is adjacent to the front of the liquid storage section 16, and the application liquid flows through the opening to the relay core 14 and the slit 18c. The liquid storage section 16 contains an agitator 16a for agitating the high-specific-gravity material contained in the application liquid in the liquid storage section 16. The agitator 16a is made of metal, resin, or the like, and may be, for example, rod-shaped or spherical, but may also have other shapes.

[0035] The coating liquid contained in the liquid storage section 16 preferably contains at least sodium polyaspartate, citric acid, one or two types of iron oxide particles selected from red iron oxide, black iron oxide, and yellow iron oxide, a film-forming resin, and water. The viscosity of the cosmetic measured at a shear rate of 192 s-1 and a temperature of 25°C is 15 mPa·s or less. The iron oxide particles in the aqueous liquid cosmetic have an average particle size of 30 nm to 100 nm as measured and calculated by dynamic light scattering. The iron oxide particles in the aqueous liquid cosmetic are preferably dispersed in water by the sodium polyaspartate. This aqueous liquid cosmetic exhibits excellent dispersibility and stability over time, even when iron oxide particles are used as a colorant in the liquid cosmetic, and exhibits no sedimentation or color separation. The "average particle size" refers to a value measured and calculated by dynamic light scattering (using a particle size analyzer, FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.).

[0036] Specifically, sodium polyaspartate is a type of anionic polymer dispersant that improves the dispersibility of iron oxide particles, which serve as a colorant. The content of the anionic polymer dispersant is preferably 0.1 to 10.0% by mass relative to the total amount of the cosmetic composition. If the content is less than 0.1% by mass, the dispersion stability of iron oxide particles, such as red iron oxide, which serve as a colorant, will be insufficient. On the other hand, if the content exceeds 10.0% by mass, the viscosity will be too high, and no improvement in dispersion stability will be observed, making it uneconomical.

[0037] The content of iron oxide particles is preferably 1.0 to 20% by mass relative to the total amount of the cosmetic composition. If the content of iron oxide particles is less than 1.0% by mass, the color development and hiding power will be insufficient, while if it exceeds 20% by mass, the viscosity will increase, which is undesirable.

[0038] Citric acid is a type of aliphatic hydroxy acid with a molecular weight of 300 or less, and is preferably contained in an amount of 0.01 to 2.0% by mass relative to the total amount of the cosmetic composition. If it is contained in an amount less than 0.01% by mass, the above effects will be insufficient, while if it is contained in an amount exceeding 2.0% by mass, the pH will decrease, which is undesirable.

[0039] Examples of film-forming resins include emulsion resins of copolymers made from one or more monomers selected from acrylic acid, methacrylic acid, or alkyl esters or derivatives thereof, styrene, and vinyl acetate. From the viewpoints of water resistance and application performance, the content of the film-forming resin (emulsion resin) is preferably 2 to 15 mass % in terms of solid content (resin content) relative to the total amount of the cosmetic composition.

[0040] The content of water is the balance after the above-mentioned components are contained. The viscosity was measured using an ELD-type viscometer manufactured by Toki Sangyo Co., Ltd., with a standard rotor of 50 rpm (shear rate: 192 [s-1]) at a temperature of 25°C (including the Examples described below).

[0041] [Front shaft 12] As shown in Figures 1 and 2, front barrel 12 is a resin product with a generally tubular, hollow structure. More specifically, front barrel 12 is shaped like a pipe with a tapered front section and a rear section of roughly the same diameter. Front barrel 12 is made of a liquid-tight material, such as polyethylene, polypropylene, ABS (Acrylonitrile butadiene styrene), or any of a variety of other synthetic resin materials.

[0042] Front barrel 12 has a front portion into which cap 24 is removably fitted, and a rear portion into which rear barrel 20 is fitted. Flange 12a is formed to protrude in the outer diameter direction on the outer peripheral surface at the boundary between the front and rear portions. When cap 24 is fitted onto front barrel 12, the rear end of cap 24 abuts against flange 12a, thereby positioning it.

[0043] The inside of front barrel 12 is angled in a stepped manner to reduce its diameter, and as shown in FIG. 2, step 12d is formed on the inner surface at the location where the rear of application part 10 and the tip of comb-teeth-shaped ink guide part 18 are located. Air vent 12b is opened (opened) slightly along the axial direction in a rear area adjacent to step 12d. Air vent 12b is formed in multiple locations in the circumferential direction. The area inside front barrel 12 adjacent to air vent 12b connects to step 12d, which has a reduced diameter. The tip of comb-teeth-shaped ink guide part 18 is fitted into and fixed to this step 12d.

[0044] Front barrel 12 reduces in diameter in a step at step 12d. From step 12d forward, the inner surface gradually tapers in diameter until it reaches opening 12c. Applicator part 10 is attached to the interior from step 12d to opening 12c. In front barrel 12, the inner diameter of opening 12c at the front is the smallest throughout the front and rear portions.

[0045] The rear portion of front barrel 12 is formed in a roughly cylindrical shape, with flange 12a formed to expand outward on the outer periphery of that rear portion. The portion of front barrel 12 rearward of flange 12a is inserted into and fixed to the tip portion of rear barrel 20 (see FIG. 1). When front barrel 12 is attached to rear barrel 20, flange 12a abuts against the tip portion of rear barrel 20, preventing front barrel 12 from slipping inside rear barrel 20.

[0046] Concave and convex portions are formed in multiple locations on the outer periphery of the rear part of flange 12a of front barrel 12 to prevent and secure rear barrel 20 when it is fitted. Concave and concave portions are also formed in locations on the inner periphery of rear barrel 20 that correspond to these multiple locations, and they fit together to maintain a liquid-tight seal and prevent it from coming loose.

[0047] [Rear shaft 20] In rear barrel 20, exterior portion 20o covers interior portion 20i, and interior portion 20i covers liquid storage portion 16. Liquid storage portion 16, which is a cosmetic tank, is fitted into the rear portion of front barrel 12 and is covered within rear barrel 20.

[0048] The rear barrel 20 has a dual structure in which the exterior portion 20o is attached to the outside of the interior portion 20i. The interior portion 20i and the exterior portion 20o are made of resin or metal. For example, the interior portion 20i may be made of resin and the exterior portion 20o may be made of metal. More specifically, it is preferable that the interior portion 20i be made of various resin materials such as polyethylene, polypropylene, ABS, etc., and the exterior portion 20o be made of a material with a glossy surface, such as metal or various alloys such as aluminum or duralumin, or ceramic. The interior portion 20i covers the liquid container 16. As a result, the liquid container 16, which serves as a cosmetic tank, is covered within the rear barrel 20 while fitted into the rear portion of the front barrel 12.

[0049] When different materials are used for the interior portion 20i and the exterior portion 20o, there is usually a difference in the thermal expansion coefficients. Therefore, when the interior portion 20i and the exterior portion 20o thermally expand, they may interfere with each other and deform. To avoid this deformation, a gap (clearance) 20b is provided between the interior portion 20i and the exterior portion 20o at the rear end of the rear axle 20. This makes it possible to prevent the interior portion 20i and the exterior portion 20o from deforming due to thermal expansion. Furthermore, providing the gap 20b can improve dimensional variations during manufacturing and impact resistance when dropped.

[0050] [Application unit 10] The applicator part of the applicator unit 10 has a brush-tip shape made of a fiber bundle of many fibers, an open-cell foam, or the like. When a brush made of a fiber bundle is used as the applicator part, it may be a fine brush with an outer diameter of 2 mm or less. The fibers used in the fiber bundle may be natural or artificial. For example, synthetic resin fibers made of polyamide fiber, nylon fiber, or polyester fiber such as PBT (polybutylene terephthalate) can be used in the fiber bundle.

[0051] 1 and 2, the applicator part 10 is made of a bundle of resin fibers. The applicator part 10 has a tapered shape that becomes thinner toward the tip. The rear end of the applicator part 10 is formed by heat welding into a flange shape (flange 10a) that protrudes toward the outer periphery. This heat welding secures the fiber bundle that makes up the applicator part 10 so that it does not come apart.

[0052] At the rear end of the applicator part 10, the spaces between the fibers in the peripheral flange 10a are tightly packed, making it difficult for the application liquid to seep in. However, at the center of the applicator part 10, which includes the axial center of the barrel, there are gaps between the fiber bundles, making it easier for the application liquid to seep in. The relay core 14 abuts against this center of the applicator part 10, and as a result, the relay core 14 guides the liquid in the liquid storage part 16.

[0053] [Relay core 14] 2, the relay core 14 has a recess 14a on the peripheral surface of its tip. When the relay core 14 is fitted into the comb-teeth-shaped ink guide portion 18, the inner peripheral protrusion 18d of the comb-teeth-shaped ink guide portion 18 fits into the recess 14a. This fitting prevents the relay core 14 from coming loose.

[0054] The relay core 14 has a structure that can exert capillary force to guide the liquid. The relay core 14 is made of a fiber bundle or a molded core made of a resin material or the like. The relay core 14 is preferably made of a material that is substantially free of formaldehyde, such as an olefin-based elastomer. This is because materials that contain formaldehyde may leach formalin from the relay core 14 into the cosmetic liquid, making them unsuitable for use as a cosmetic tool. Furthermore, the relay core 14 is more preferably made of a material that does not contain acetal resins such as polyacetal, phenolic resins, or urea resins and melamine resins used in adhesives.

[0055] [Cosmetics] The liquid storage section 16 contains a liquid cosmetic solution. The liquid cosmetic preferably contains, for example, at least carbon black, water, 0.5 to 5% by mass of a dispersant made of a film-forming resin, 2 to 15% by mass (solids content) of a film-forming agent, and 0.5% by mass or less of a surfactant, and may further contain other materials. The liquid cosmetic preferably has a viscosity in the range of 2 to 8 mPa·s at a temperature of 25°C and a shear rate of 3.83 S-1, as measured by an ELD-type viscometer.

[0056] [Cap 24] [Exterior part 24d and outer cap 24o] 1 and 2, the cap 24 has a cylindrical shape with a closed front end and an open rear end. The exterior part 24d visible from the outside of the cap 24 has a cylindrical shape with a closed front end and an open rear end. The outer cap 24o is housed inside the cylinder of the exterior part 24d.

[0057] The exterior part 24d and the outer cap 24o are made of resin, metal, ceramic, or the like. The exterior part 24d and the outer cap 24o may be made of the same material or different materials. For example, the outer cap 24o may be made of resin, and the exterior part 24d may be made of metal. More specifically, the outer cap 24o may be made of various resin materials such as polyethylene, polypropylene, ABS, or the like, and the exterior part 24d may be made of metals such as various alloys such as aluminum and duralumin, or ceramic.

[0058] Typically, different materials have different thermal expansion coefficients, so when different materials are used, there is a risk that the exterior part 24d and the outer cap 24o may interfere with each other due to thermal expansion. To avoid this, a gap 24a is provided between the exterior part 24d and the outer cap 24o, as shown in FIG. 2(b). By providing the gap 24a, it is possible to prevent the top surface 24f, which has been deformed due to thermal expansion, from interfering with the exterior part 24d. Furthermore, by providing the gap 24a, it is possible to absorb dimensional variations during manufacturing and improve impact resistance when dropped.

[0059] [Outer cap 24o and inner cap 24i] 3 shows the cap 24 without the exterior part 24d, FIG. 4 shows the cap 24 in FIG. 3 disassembled, FIG. 5 shows the outer cap 24o alone, and FIG. 6 shows the inner cap 24i alone.

[0060] As shown in FIGS. 3 and 4, the outer cap 24o accommodates the inner cap 24i and the spring 24s.

[0061] 5, the outer cap 24o has a cylindrical shape with a top surface 24f that is closed at the front end and an opening 24b at the rear end. The outer cap 24o also has an inward protrusion 24o1. The inward protrusion 24o1 is annularly provided on the inner circumferential surface of the outer cap 24o so as to be perpendicular to the longitudinal direction of the outer cap 24o.

[0062] The inner diameter of the outer cap 24o preferably has a tapered shape, narrowing toward the opening and widening toward the top surface 24f. The taper angle of this tapered shape is preferably about 0.2 degrees, for example. This allows for a wider range of molding conditions for the outer cap 24o. It also makes it less likely for chipping to occur when cutting the inward protrusions 24o1.

[0063] As shown in FIG. 6, the inner cap 24i is made of synthetic resin, such as polypropylene, and has a generally tubular, hollow structure. The inner cap 24i is shaped like a pipe, tapering toward the front and maintaining a generally constant diameter toward the rear. The inner cap 24i also has a flange 24i1. When the cap 24 is assembled, the outer circumferential surface of the inner cap 24i from the flange 24i1 toward the front is configured to fit inside the spring 24s. The flange 24i1 has a flange shape that expands in diameter outward from an outer circumferential surface 24i5 slightly forward of the longitudinal center of the inner cap 24i.

[0064] The outer diameter of the flange 24i1 is smaller than the inner diameter of the outer cap 24o. To ensure clearance, for example, the outer diameter of the flange 24i1 is preferably smaller than the inner diameter of the outer cap 24o by 0.1 to 0.3 (mm). The outer diameter of the rear end of the inner cap 24i is smaller than the inner diameter of the outer cap 24o. Furthermore, the longitudinal length of the inner cap 24i is shorter than the longitudinal length of the interior of the outer cap 24o. Therefore, the outer cap 24o can accommodate the entire inner cap 24i, including the flange 24i1 and the rear end.

[0065] The flange 24i1 has a front surface 24i2 facing forward and a back surface 24i3 facing rearward. A step 24i7 is further formed on the front side of the front surface 24i2. The step 24i7 stabilizes the radial position of the end 24s1 or 24s3 when the spring 24s slides after the cap is assembled. The flange 24i1 also has a curved surface 24i4 as an R-shape connecting the back surface 24i3 and the outer peripheral surface 24i5. The curved surface 24i4 improves the crack resistance of the flange 24i1 and prevents cracking when the flange 24i1 is press-fitted into the inward protrusion 24o1.

[0066] Furthermore, the pressing force of the spring 24s pressing the spring receiving surface 24i22 is P (MPa), and the volume of the connecting portion 24v in the area between the spring receiving surface 24i22 and the back surface 24i3 of the flange portion 24i1 is V (mm 3 ), V / P=27 to 39 is satisfied. FIGS. 3 and 6 show an outline of the receiving surface 24i22 and the connecting portion volume V of the connecting portion 24v. Details will be explained later with reference to FIG. 15 and the like.

[0067] When assembling the cap 24, the inner cap 24i is inserted into the outer cap 24o through the opening with the spring 24s placed on the front side thereof. During insertion, the flange 24i1 of the inner cap 24i is press-fitted onto the inward protrusion 24o1 of the outer cap 24o, and the flange 24i1 rides over the inward protrusion 24o1 to fit (over-fit). Due to this over-fitting, the flange 24i1 is held forward of the inward protrusion 24o1, as shown in FIG. 3(d).

[0068] Since assembly is performed using a jump-over fit, the flange 24i1 must be able to climb over the inner protrusion 24o1 when attaching the inner cap 24i to the outer cap 24o. At the same time, a sufficient fitting force is required to prevent the inner cap 24i from slipping off the outer cap 24o. To ensure sufficient fitting force, the outer diameter of the flange 24i1 is configured to be somewhat larger than the inner diameter of the inner protrusion 24o1. This configuration provides an overlap between the outer diameter of the flange 24i1 and the inner diameter of the inner protrusion 24o1. This overlap is preferably 0.05 to 0.5 mm, for example. In this case, the flange 24i1 and the inner protrusion 24o1 have a fitting force of 10 to 80 N after the jump-over fit.

[0069] 1(b), when the cap 24 is closed, the inner protrusion 24o1 abuts and slides against the outer peripheral surface of the inner cap 24i while maintaining an airtight seal. This prevents the inner cap 24i from rattling and the application part 10 from drying out. In this way, the inner protrusion 24o1 serves both to prevent the inner cap 24i from falling off the outer cap 24o and to abut and slide against the outer peripheral surface of the inner cap 24i while maintaining an airtight seal when the cap 24 is closed.

[0070] 1, when the applicator is not in use, cap 24 is attached so as to cover the area from applicator part 10 to front barrel 12. At this time, inner cap 24i is in airtight contact with the sloped outer surface of front barrel 12, behind air vent 12b.

[0071] [Spring 24s] The spring 24s is a biasing member, and is a barrel-shaped coil spring made of an elastic material such as metal or resin. As shown in Fig. 7, the spring 24s has end portions 24s1 and 24s3 and a middle portion 24s2. Comparing the inner and outer diameters, the inner and outer diameters of the end portions 24s1 and 24s3 are smaller than the inner and outer diameters of the middle portion 24s2. Meanwhile, comparing the winding density, the winding density of the end portions 24s1 and 24s3 is higher than the winding density of the middle portion 24s2.

[0072] When cap 24 is closed, front barrel 12 presses inner cap 24i forward. Accordingly, front surface 24i2 of flange 24i1 presses spring 24s forward, compressing spring 24s between top surface 24f and front surface 24i2.

[0073] At this time, the end portions 24s1 and 24s3 have a smaller diameter and higher density than the middle portion 24s2, and therefore the degree of elastic deformation is smaller. Therefore, the inner cap 24i can press the spring 24s while stably maintaining contact between the end portion 24s1 and the top surface 24f and between the end portion 24s3 and the front surface 24i2. On the other hand, the middle portion 24s2 has a relatively larger diameter and lower density, and therefore the degree of elastic deformation is greater. Therefore, sufficient elastic force can be ensured by the elastic deformation of the middle portion 24s2.

[0074] When the cap 24 is assembled, the spring 24s is entirely housed in the outer cap 24o, so that the outer diameter of the spring 24s, particularly the outer diameter of the middle portion 24s2, is smaller than the inner diameter of the outer cap 24o.

[0075] As shown in Fig. 3, inside outer cap 24o, spring 24s biases inner cap 24i rearward. Outer cap 24o is fitted onto front barrel 12 and abuts against flange 12a (see Fig. 1).

[0076] As shown in Fig. 5, fixing protrusion 24g is formed on the rear end side of the inner circumferential surface of outer cap 24o. Protrusion 24g fits into recess 12e on the outer circumferential surface of front barrel 12, preventing cap 24 from coming off front barrel 12 (see Fig. 1). Rear end 24e of outer cap 24o abuts against flange 12a, closing cap 24.

[0077] [1.2 Actions and Effects of the First Embodiment] According to the cosmetic applicator of the first embodiment, a sufficient engagement margin is provided between the flange portion 24i1 and the inward projection 24o1. This increases the engagement force between the flange portion 24i1 and the inward projection 24o1. As a result, the inner cap is less likely to come off the assembled cap.

[0078] 6, a curved surface 24i4 is provided on the back surface 24i3 of the flange portion 24i1, and a curvature R is provided at the base of the flange portion 24i1. This makes it possible to make the flange portion 24i1 less likely to crack when the inner cap 24i is press-fitted into the outer cap 24o during cap assembly.

[0079] Furthermore, the pressing force of the spring 24s pressing the spring receiving surface 24i22 is P (MPa), and the connecting portion volume, which is the volume of the connecting portion 24v in the region between the spring receiving surface 24i22 and the back surface 24i3 of the flange portion 24i1, is V (mm 3 ), V / P=27 to 39 is satisfied. The effect of this will be described later with specific examples using FIGS. 13 to 16.

[0080] With reference to Figure 8, cracking of the flange portion 24i1 during cap assembly will be described. When assembling the cap, the inner cap 24i is inserted from its front end into the open end of the outer cap 24o. As the inner cap 24i advances forward, the flange portion 24i1 comes into contact with the inner protrusion 24o1, as shown in the area surrounded by a frame line 100 in Figure 8(a). From this state, when the inner cap 24i is pressed forward, the flange portion 24i1 gets over the inner protrusion 24o1 and fits (over-fitting).

[0081] During this clearance, the state of the frame line 100 in FIG. 8(a) is shown enlarged in FIG. 8(b). The flange 24i1 falls backward. Normally, the flange 24i1 that falls backward recovers and returns to its original position after clearing the inner protrusion 24o1. However, if the flange 24i1 breaks (cracks) during clearance, it may not return to its original position after clearing the inner protrusion 24o1 (the flange in the broken state is indicated by the symbol 24i1-1). To prevent this breakage, in this embodiment, a connection portion 24v (see FIG. 6) with a suitable radius is provided at the base of the flange 24i1, thereby increasing strength in the bending direction and preventing the flange 24i1 from breaking (cracks).

[0082] Furthermore, according to the cosmetic applicator of the first embodiment, the outer cap 24o has a tapered shape in which the inner diameter is narrow at the open end and wide on the top surface 24f side (the top surface side of the cap 24). This prevents the inward protrusion 24o1 from being deformed when the mold is released during molding of the outer cap 24o, improving moldability.

[0083] By providing a curvature R at the base of the flange portion 24i1, it is possible to improve crack resistance while suppressing the occurrence of sink marks.

[0084] [2. Second Embodiment] The cap 24 of a cosmetic applicator according to a second embodiment of the present invention will now be described. The cap of the second embodiment has an inner cap 24j in which multiple recesses 24j6 are formed on the front surface of a flange 24j1, instead of the inner cap 24i used in the first embodiment. The rest of the configuration is the same as that of the first embodiment.

[0085] 9, the inner cap 24j has a flange 24j1, a front surface 24j2, a back surface 24j3, a curved surface 24j4, an outer peripheral surface 24j5, and a step 24j7. The flange 24j1, the front surface 24j2, the back surface 24j3, the curved surface 24j4, the outer peripheral surface 24j5, and the step 24j7 are similar to the flange 24i1, the front surface 24i2, the back surface 24i3, the curved surface 24i4, the outer peripheral surface 24i5, and the step 24j7, respectively, and therefore will not be described again. In addition, the inner cap 24j has a plurality of recesses 24j6 formed in the front surface 24j2. The recesses 24j6 are formed to reduce material loss as a countermeasure against sink marks during injection molding.

[0086] According to the second embodiment, by forming the depression 24j6 by removing material from the front surface 24j2 of the flange 24j, it is possible to suppress the occurrence of sink marks due to the R (curved surface 24j4). Therefore, even if a large R is provided in the flange 24j, it is possible to improve crack resistance without inviting weakening due to the occurrence of sink marks.

[0087] Furthermore, the pressing force of the spring 24s pressing the spring receiving surface 24i22 is defined as P (MPa), and the connecting portion volume, which is the volume of the connecting portion 24v, which is the region of the flange portion 24i1 between the spring receiving surface 24i22 and the back surface 24i3, is defined as V (mm 3 ), V / P=27 to 39 is satisfied. FIG. 9 shows an outline of the receiving surface 24j22 and the connecting portion 24v. Details will be explained later with reference to FIGS. 13 to 16.

[0088] [3. Actions and Effects of Comparative Examples and Examples] 10(a) shows an example of an inner cap 30 of a comparative example, and (b) shows an example of an inner cap 36 of an embodiment. In Fig. 10, the inner caps 30 and 36 differ in the shape of the curvature R at the base on the back side of the flange, but are common in material, longitudinal length, inner and outer diameters of the front end and rear end, outer diameter of the flange, etc.

[0089] The inner cap 30 of the comparative example is for comparison purposes, and does not have a large curved surface R at the base 30b on the back side of the flange portion 30a.

[0090] On the other hand, the inner cap 36 of the example corresponds to the inner cap 24i according to the first embodiment. The inner cap 36 of the example has a curved surface 36b with a curved surface R formed at the base on the back side. In this embodiment, the size of the curved surface R is 0.3 to 1.2 (mm). Note that if the curved surface R is made larger, sink marks will occur on the front surface of the flange during injection molding.

[0091] 11 shows an inner cap 30 of a comparative example in (a) and (b), an inner cap 36 according to the first embodiment in (c) and (d), and an inner cap 38 according to the second embodiment in (e) and (f). The inner cap 30 of the comparative example shown in (a) and (b) of FIG. 11 is the same as that shown in FIG. 10, and the inner cap 36 of the example shown in (c) and (d) of FIG. 11 is the same as that shown in FIG. 10.

[0092] 11(e) and (f) shows an inner cap 38 of Example 21, in which the front surface of the flange 38a is recessed and twelve depressions 38c are formed in the front surface of the flange 38a (the depressions 38c correspond to the depressions 24j2 of the flange 24j1 of the second embodiment).Other aspects of the inner cap 38 (such as the material, longitudinal length, inner and outer diameters of the front end and rear end, flange size, thickness, etc.) are the same as those of the inner cap 36 of Example 13.

[0093] Figures 12(a) and (b) show a comparison of plan views from the front of the inner cap with and without the recess 38c. As shown in Figure 12(a), the absence of the recess 38c can cause sink marks 30c in the flange 30, but as shown in Figure 12(b), the provision of the recess 38c can prevent sink marks in the flange 38a.

[0094] [4. Drop impact resistance test] 4.1 Test Method

[0095] In order to confirm the effects of the present invention, a drop impact resistance test was conducted on the inner caps of the examples and comparative examples using a hole gauge 40 shown schematically in Fig. 13. The inner caps of the test specimens (Examples 1 to 11, Comparative Examples 1 to 4) are indicated by reference numeral 46, and the flanges are indicated by reference numeral 46a.

[0096] In this drop impact resistance test, a hole gauge 40 was used, which has a hole 42 (inner diameter of which is the outer diameter of the step portion 24i7 and the step portion 24j7 + φ0.1 (mm)) shown in FIG. 13, which imitates the undercut portion of the inward protrusion 24o1 on the inner diameter of the outer cap 24o as shown in FIG. 3 of the first embodiment.

[0097] Then, the inner caps 46 of Examples 1 to 11 and Comparative Examples 1 to 4 were set as test specimens in the hole gauge 40, and a drop impact resistance test was performed by dropping a 200 (g) weight 44 from multiple heights with the flange portion (indicated by symbol 46a) engaged with the shoulder portion 40a of the hole gauge 40.

[0098] Specifically, this drop impact resistance test reproduced the situation in which a spring is installed inside the cap to allow the flange of the inner cap to overcome the undercut of the outer cap and fit into place. As shown in Figure 13, when the tip of the inner cap is inserted into the hole 42, the inner cap 46 is set in the hole gauge 40 with the tip facing downward and the rear end facing upward. From this state, a weight 44 is dropped from directly above the rear end of the inner cap 46, and the state of damage to the flange of the inner cap is then observed.

[0099] FIG. 14 illustrates the spring receiving surface area S and the connection volume V of the inner cap 46.

[0100] As shown by hatching in Fig. 14, the spring receiving surface 46s is a region on the front surface of the flange 46a that has a spring receiving surface area S, and corresponds to the connecting portion 24v, which is a region on the front surface of the flange 46a onto which a radial cross section of the end 24s3 of the spring 24s is projected, as shown in Figs. 1, 7, etc. The portion of the flange 46a that is projected in the axial direction from the spring receiving surface 46s is the connecting portion 46v. The outer peripheral surface of the inner cap 46 is denoted by the reference symbol 46c.

[0101] Figure 15 shows the volume V (mm 3 The connecting portion 46v has a generally doughnut shape or a generally hollow cylindrical shape that is made up of the inner portion of the flange portion 46a.

[0102] 15(a) and (b) are longitudinal cross-sectional views of the vicinity of the flange 46a. The inner surface Li of the connection portion is the outer peripheral surface of a cone formed by excluding the flange 46a from the inner cap 46, and is an extension of the outer peripheral surface 46c. The spring receiving surface 46s is located on the front surface of the flange 46a, and the rear surface is indicated by 46b. The outer surface Lo is formed by a set of perpendicular lines extending from each point on the outer diameter of the spring receiving surface toward the rear surface of the flange, along the axis of the inner cap 46. In other words, the outer surface Lo is the side surface of a cylinder whose circumference is the outer diameter of the spring receiving surface. The connection portion volume V is the volume of the annular connection portion 46v enclosed by the spring receiving surface 46s, the inner surface Li, the outer surface Lo, and the rear surface 46b.

[0103] As shown in FIG. 15(a), in the conventional inner cap, both the front surface and the rear surface 46b of the connecting portion 46v are flat.

[0104] As shown in Fig. 15(b), the inner caps of Examples 1 to 5 have a flat front surface of the connection portion 46v and a curved rear surface 46b with a rounded shape (46r). When the inner cap 46 has a recess as in the second embodiment (see Fig. 9), the connection portion volume V is assumed to be smaller by the amount of the recess. The value of the connection portion volume V is calculated based on the dimensional measurements of each sample.

[0105] FIG. 16 is a table summarizing the results of this drop impact resistance test, and (a) shows the connection volume V (mm 3 ), surface area S(mm 2 ), spring load (N) when the cap is closed, pressing force (MPa) when the cap is closed, V / P, and evaluation results are shown, and (b) shows the specifications of spring 24s (see Figure 7).

[0106] The inner caps of Comparative Examples 1 to 4 correspond to the inner cap 30 in Fig. 10(a) and do not have a curved surface R at the base 46b of the flange 46a. The inner caps of Examples 1 to 5 have different connection volume V, such as a curved surface 46r at the flange 46a.

[0107] The spring specifications are made by bending SUS wire with a wire diameter of 0.4 to 0.5 mm into a barrel-shaped coil spring (see spring 24s in Figures 1 and 7). The spring bearing surface area S (mm 2 ) is the projected area of ​​the radial cross section of the spring 24s at the end 24s3 where the spring 24s contacts the flange (see FIG. 7).

[0108] The spring receiving surface area S shown in FIG. 16 is, for example, 6.9 mm when the radially projected outer diameter of the spring 24s (see FIG. 7) is 2.95 mm and the wire diameter of the spring is 0.4 mm. 2 ) In the case where a recess 24j6 is provided on the spring receiving surface like the inner cap 24j of the second embodiment (see FIG. 9), the spring receiving surface area S is the area when the spring receiving surface is regarded as a flat surface without any recess.

[0109] The pressing force P [MPa] corresponds to the magnitude of the pressure that the spring load [N] when the cap is closed presses on the spring receiving surface S. In other words, the force P (when the cap is closed) [MPa] is calculated by multiplying the spring load [N] when the cap is closed by the spring receiving surface area S (mm 2 ) is the value divided by

[0110] V / P is the connection volume V (mm 3 ) divided by P (with cap closed) (MPa).

[0111] Tests A and B were conducted for evaluation (evaluation results). In test A, weight 44 was dropped from a height of 10 cm onto each of the inner caps. In test B, weight 44 was dropped from a height of 25 cm onto each of the inner caps.

[0112] The following applies to both tests A and B. Five inner caps (n=5) were prepared as samples for each of comparative examples 1 to 3 and examples 1 to 5, and a weight was dropped on each sample. The weight 44 weighed 200 g. The inner caps were made of polypropylene. The results of each test were evaluated using three levels: A, B, and D.

[0113] Evaluation A: Indicates that there was no damage to the flange in any of the samples.

[0114] Evaluation B: Although some samples had breakage of the flange, this did not pose a problem in practical use.

[0115] Rating D: The flanges of all samples were broken, indicating that there were problems in practical use.

[0116] Comparing the evaluation results of Comparative Examples 1 to 4 and Examples 1 to 11, Comparative Examples 1 to 4 received a rating of D in both tests A and B, whereas Examples 1 to 11 received a rating of B or higher in at least test A. This shows that Examples 1 to 11 have higher strength than Comparative Examples 1 to 4. Therefore, satisfying the relationship V / P = 27 to 39 is effective, proving the usefulness of the present invention.

[0117] Among them, Examples 2 to 4, which received an evaluation of A in Test A, are found to have particularly high strength. Therefore, since the relationship of V / P=30 to 35 is satisfied, it is proven that they are even more effective and have even greater usefulness.

[0118] The flange of Comparative Example 4 had a larger connection volume V and was thicker than those of Comparative Examples 1 to 3 and Examples 1 to 11, and because of the thickness, sink marks occurred in the flange. These sink marks reduced the molding quality of the inner cap, which in turn reduced the strength of the flange, leading to a rating of D.

[0119] Based on the results of the drop impact resistance test described above, the inventors have found that when designing a cap for a cosmetic applicator, in order to avoid damage to the flange of the inner cap, it is preferable to design it so that the V / P value is 27 to 39, and more preferably 30 to 35.

[0120] The above embodiment is one embodiment of the present invention, and can be freely modified and implemented within the scope of the present invention. [Industrial Applicability]

[0121] The cosmetic applicator of the present invention can be used as a container for applying cosmetics. [Explanation of symbols]

[0122] 10 Application section 12 front axis 14 Relay core 16 Liquid storage section 18 Comb-shaped ink guide part 20 rear axle 24 Cap 24i Inner Cap 24 Cap 24a void 24b opening 24d Exterior part 24e Rear end 24f top surface 24g convex part 24i Inner Cap 24i1 Tsubabe 24i2 front 24i3 back 24i4 curved surface 24i5 Outer surface 24i7 Stepped section 24j Inner cap (second embodiment) 24j1 Tsubabe 24j2 front 24j3 back 24j4 curved surface 24j5 Outer surface 24j6 hollow 24j7 Multilayered section 24o outer cap 24o1 Medial process 24s Spring 24s1 end 24s2 Midsection 24s3 end 24v connection 30 Inner cap (comparison example) 30a Tsubabe 30b root 36 Inner cap (Example) 36 Tsuba 36a Tsuba 36b curved surface 36c sink mark 38 Inner cap (Example) 38a Tsuba 38b Curved surface 40 hole gauge 42 holes 44 Weight 46 Inner cap 46a Tsuba 46v connection

Claims

1. A cap for a cosmetic applicator includes a cylindrical outer cap, an inner cap made of synthetic resin and positioned on the inner surface of the outer cap, and a spring that presses the inner cap toward the opening of the outer cap. The back surface of the spring receiving surface of the inner cap is formed into a continuous line. The pressure P (MPa) applied when attaching the flange of the spring inner cap to the barrel is used to determine the volume V (mm ３ ) and A cap for a cosmetic applicator, characterized in that the pressing force P and the connection portion volume V satisfy the relationship V / P = 27 to 39.

2. The inner cap has a side surface and a flange portion, 2. The cap of a cosmetic applicator according to claim 1, wherein the flange has a front surface located on the leading barrel side and a back surface located on the rear barrel side, the front surface having a spring receiving surface that receives one end of the spring, and the back surface having a continuous curved surface that is connected to the side surface.

3. The cap for a cosmetic applicator according to claim 2, wherein the flange has a recess on the front surface.

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