EP0651955A1 - Brush for application of nailvarnish, or similar product - Google Patents

Abstract

The brush (1) for application of nail varnish or similar product includes bristles (3, 4) forming a tuft (2) which is obtained from a bundle of substantially parallel bristles folded in two halfway along their length, the bristles being fastened to the end of a wand (5) by engagement, with gripping, of the folded part (8) of the tuft of bristles in a housing (9) opening up at the end of the wand. The bristles (3, 4) have sections accepting a circumscribed circle of constant diameter and are chosen from at least two groups, the bristles (3) of one group being arranged so as to have a mechanical behaviour on flexing which is different from that of the bristles (4) of the other group so that, during folding and gripping of the different groups of bristles, these groups give a ventilated and spread-out brush tuft (2), with relatively large spaces between bristles which favour good capillarity for varnishes, the viscosity of which may vary over a wide range. <IMAGE>

Description

The invention relates to a brush for applying nail varnish, or the like, of the kind of those which have bristles forming a tuft, fixed to the end of a rod and oriented substantially in the axial direction of the rod.

FR-A-2 687 055 shows a brush of this type which allows, with the conventional compositions of nail varnish, to carry out a precise and rapid application of the varnish. In particular, with such a brush, it is no longer necessary to immerse the brush many times in the container to make up a nail because the product load taken up with the brush is relatively high.

The conventional nail varnish compositions currently used have viscosities of approximately 200 centipoise to 400 centipoise (200 to 400 cps). However, developing nail varnish compositions have higher viscosities, in particular around 600 cps (centipoise). Even more viscous compositions are also contemplated.

It appeared, during tests, that the known nail varnish brushes, in particular a brush such as that mentioned above, are not entirely satisfactory for applying varnish compositions whose viscosity is greater than the range of viscosities classics. In particular, the brushes known to date are not entirely satisfactory for applying varnishes whose viscosity is of the order of, or greater than, 600 cps.

The invention aims, above all, to provide a nail varnish brush which allows, even with varnishes of high viscosity, in particular greater than 600 cps, to apply the product under good conditions, while being usable for applying classic nail polish.

The invention also aims to provide a brush which, while meeting the requirement set out above, remains simple and economical to manufacture, and of conventional use.

To solve this problem, according to a first solution, a brush according to the invention, for applying nail varnish or a similar product, comprises bristles forming a tuft, obtained at from a bundle of substantially parallel hairs, folded in half approximately halfway along, the hairs being fixed to the end of a rod by engagement, with clamping, of the folded part of the tuft of hairs in a housing s opening at the end of the rod, the bristles having cross sections admitting a circumscribed circle of constant diameter, this brush being characterized in that the bristles of the tuft are chosen from at least two groups, the bristles of a group being arranged to have a mechanical flexural behavior different from that of the bristles of the other group so that, when bending and tightening the different groups of bristles, these groups give an airy brush tuft spread out with spaces between relatively large hairs, favorable for good capillarity for varnishes whose viscosity can vary over a wide range.

According to a first possibility, the bristles of a group are made of a material different from the bristles of another group, these different materials having different coefficients of elasticity resulting in different mechanical behavior of the groups of bristles, the coefficient of elasticity of the material of a hair of a first group varying from 10% to 200% relative to the coefficient of elasticity of the material of a hair of another group.

According to another possibility which can be combined with the previous one, the hairs of one group have a shape of cross section different from that of the hairs of another group, these differences in shape leading to differences in resistance to bending, even if the material of the hairs of the different groups is identical.

A first group of bristles may comprise 5 to 95% of the total number of bristles of the brush, the second group, or all of the other groups, being constituted by the complement, namely 95 to 5% relative to the total number of bristles.

The brush may include a third group of different bristles, the number of which may vary from 90% to 10% relative to the total number of bristles of the brush.

The most flexible bristles can be made of polyamide, for example the polyamide known under the trade name Tynex from the company Dupont de Nemours, or of block ether polyamide or of polyester elastomer. The material used for the bristles less flexible can be chosen from the group: Rilsan, polyamide, polyethylene, polytetrafluoroethylene, polyvinylidene fluoride, polyacetate, polyethylene terephthalate.

To solve the same problem, according to a second solution, it is also possible to use a housing of particular shape: the invention therefore also relates to a brush for applying nail varnish, or similar product, comprising bristles forming a fixed tuft. at the end of a rod by engagement of the tuft of bristles in the housing opening at the end of the rod, the bristles having cross sections admitting a circumscribed circle of constant diameter, this brush being characterized by the fact that said housing has a flared shape whose large base is located at the end of the rod, this shape giving a tuft of airy brush and spread with relatively large spaces between the bristles, favorable for good capillarity for varnishes whose viscosity can vary over a wide range.

The tuft of the brush can be obtained from a bundle of substantially parallel bristles, folded in half approximately halfway, the folded portion of the tuft of bristles being engaged with clamping in the housing of the rod.

In addition, the cross section of the end of the rod can have any shape. It can, for example, be round, square, rectangular, triangular, oval or cruciform.

In particular, the housing can be in the form of a truncated cone, pyramid, funnel; it can also be cylindrical with a shoulder defining an area of larger diameter than the bottom area of the housing where the implantation of the tuft takes place.

According to the second solution, the hairs can be identical or different. They are made in particular of synthetic or natural material. The natural material can normally be chosen from natural bristles, preferably of animal origin. The synthetic material can be chosen from the group formed by polyamides, polyesters, polyether-block amides, polyethylenes, polytetrafluoroethylenes, polyvinylidene fluorides, polyacetals, polyethylene terephthalates.

Preferably, bristles are used whose diameter is chosen from 11 hundredths to 40 hundredths of a millimeter, and preferably from 14 hundredths to 17 hundredths of a millimeter. The hairs are preferably hollowed out.

The brush of the invention is suitable for applying, in particular, varnishes whose viscosity is in the range of 200 to 2,000 cps, limits included. In practice, the brush of the invention allows correct application of liquid product, the viscosity of which can vary within a range ranging from approximately 1.2 to approximately 3500 cps.

In a manner known in itself, the folded area of the bristles can be held, in the rod, by a staple forced into the housing of the rod.

The length along which the bristles of the brush protrude beyond the end of the rod can be between 12 and 30 mm, limits included.

The diameter of the circle circumscribed to the cross section of a bristle is between 3/100 mm and 18/100 mm, limits included; this diameter is the same for all the bristles of the same brush.

The shape of the cross section of a bristle is chosen, in particular from the following shapes: solid circular, hollow circular, horseshoe, V-shaped, flat, cruciform, or provided with capillary grooves.

Additives that modify the surface condition and surface tension can be incorporated into the material of the brush bristles.

The invention consists, apart from the arrangements set out above, of a certain number of other arrangements which will be more explicitly discussed below in connection with exemplary embodiments described with reference to the attached drawing, but which are in no way limiting.

Figure 1 of this drawing is an elevational view of a nail varnish brush according to the invention.

Figure 2 is a schematic view on a larger scale, in partial axial section, of the end of the rod provided with the tuft of bristles.

Figure 3 is a view of the substantially parallel bundle of bristles used in the manufacture of the brush.

Figure 4 is a schematic view illustrating the engagement of the tuft of hairs folded into the housing of the rod.

Figure 5 is a schematic view, on a larger scale, of bristles of the brush belonging to two different groups.

Figures 6 to 11 are diagrams of different possible cross sections of the bristles, inscribed in a circle of constant diameter.

Figures 12 and 13 show, in elevation, on a large scale, two possible shapes for the tip of the brush.

Figure 14 is a side view of a possible end for the tip of the brush.

Figures 15 to 17, finally, illustrate possible cross sections for housing the end of the brush receiving the tuft of bristles.

Referring to Figure 1 of the drawings, one can see a brush 1 for applying nail polish comprising a tuft 2 of bristles 3, 4 fixed to the end of a rod 5, and oriented substantially in the direction axial of the rod. A cylindrical sleeve 6 is integral with the end of the rod 5 opposite the tuft 2, and engaged in the sleeve. This cylindrical sleeve 6 serves as the brush operating member; it also serves as a stopper intended, for example, to be screwed onto the neck of a bottle of varnish.

The tuft 2 is obtained from a bundle 7 (FIG. 3) of bristles 3, 4 which are substantially parallel, folded in half approximately halfway as illustrated in FIG. 4. The tuft 2 is fixed to the end of the rod 5 by engagement, with clamping, of the folded part 8 (see FIG. 2) of the tuft of bristles in a housing 9 formed by a blind hole opening at the end of the rod 5.

All the bristles 3, 4 have a cross section admitting a circumscribed circle C (see FIGS. 6 to 11) of constant diameter.

The bristles 3, 4 are chosen from at least two groups: the bristles 3 of one group are arranged to have a mechanical behavior to flexion different from that of the bristles 4 of the other group so that, during folding and tightening of the different groups of bristles, these groups give an airy and spreading tuft 2.

In particular, a bristle 3 (see FIG. 5) for example more rigid than a bristle 4 will form, during bending, a "V" more open than that formed by a bristle 4. Thus a relatively large gap i is created between the end of the bristle 3 and the neighboring end of a bristle 4. This interstice naturally decreases from the free end of the bristles to the bending zone 8. The existence of the gap between the bristles 3 and 4 is favorable for good capillarity for varnishes of high viscosity.

The ventilation and spreading of the tuft 2 of bristles results from the combined effect of the folding of the bundle 7 substantially at mid-length and the engagement with tightening of the folded part 8 in the housing 9. The cooperation of a zone of the tuft 2 with the walls of the housing 9, and the tightening of this tuft in the housing, are involved in the formation of the plume of the tuft 2.

Generally, the tuft 2 is produced as illustrated in FIGS. 3 and 4, by placing the middle zone of the bundle 7 on the inlet of the housing 9 of the rod 5. A staple 10 is engaged around the zone situated substantially at mid length of the bundle 7 and is pressed into the housing 9 causing the bristles 3, 4 to fall back which bear against the edge of the housing 9. During this operation, the clip 10 folds back so as to clamp the bristles and is forcibly engaged in the rod 5.

The clip 10 is made from a metal wire, bent in a U, the section of which can be circular, flat rectangular, or square. The diameter or the long side of the section of the wire is advantageously between 0.2 mm and 1.5 mm.

The bottom zone 9 a (FIGS. 2 and 15) of the housing 9, where the stapling takes place, can be cylindrical of revolution, while the upper part 9 b of the housing located beyond this cylindrical zone has a flared shape, frustoconical of revolution whose large base is located at the open end of the housing 9. The tuft 2 of the brush, located in such a housing, has a frustoconical shape with a substantially circular base.

Other forms are possible for housing. For example, as illustrated in FIG. 16, the upper part 9 ' b (flared or not) may have a bean or banana-shaped section. According to another possibility, the section of the upper part has an oval shape, a flattened rectangular shape, or a cross shape.

Figure 17 illustrates an advantageous variant of the shape of the 9 '' housing. We find, in the bottom of the housing, a cylindrical part of revolution 9 '' a . The upper flared part 9 '' b has a substantially flattened rectangular shape, the long sides of which are curved to present an outward concavity. The end of the rod 5 therefore has two concave faces c forming, in a way, a supply channel for the flow of the product from the rod to the tuft of the brush.

According to the different shapes of the housing section 9, 9 ', 9' ', and in particular of the flared part, the contour of the tuft 2 is modified accordingly and reproduces, on a larger scale, substantially the shape of the housing section .

To ensure a different mechanical behavior when flexing the two groups of bristles 3 and 4, according to a first possibility, different materials having different elasticities are chosen for each group of bristles 3, 4. The elasticity of the material is characterized by the modulus of elasticity or Young's modulus. The elasticity of the material of a pile 3 of the first group varies, preferably, from 10% to 200% relative to the elasticity of a pile 4 of the second group.

Under these conditions, the bristles 3 and 4 of different materials, even if they have sections of identical shape, inscribed in a circle of the same diameter, will have a different mechanical behavior when flexed.

The most flexible bristles can be made of a polyamide, for example the polyamide known under the trade name Tynex from the company Dupont de Nemours, or in block ether polyamide, or in polyester elastomer. The least flexible bristles can be made from a material chosen from the group: Rilsan, polyamide, polyethylene, tetrafluoroethylene, polyvinylidene fluoride, polyacetate, polyethylene terephthalate.

Examples of brushes made with bristles of different materials with the same circumscribed circle diameter are given below.

A first brush was produced with bristles of 8/100 mm diameter with 50% bristles in Rilsan and 50% bristles in PA6.10 (polyamide 6.10).

Another example is a brush made with 30% of Rilsan bristles of diameter 8/100 mm and 70% of PA6.6, also of diameter 8/100 mm.

Another example corresponds to 30% of PET (polyethylene terephthalate) hairs with a diameter of 10/100 mm and 70% of PA6.12 hairs also of 10/100 mm.

According to another possibility, which can be combined with the previous one, a different mechanical flexural behavior of a group of bristles 3 is obtained vis-à-vis a group of bristles 4 by giving the cross section of the bristles different shapes leading to differences in flexural strength.

For example, the less flexible bristles 3 will have a solid circular section as illustrated in FIG. 6, while the more flexible bristles 4 will have a hollow circular section such as that of FIG. 7, the outside diameter of the bristles being the same.

Other shapes of sections can be combined, for example a horseshoe section such as that of FIG. 8, a V-shaped section such as that of FIG. 9, or a flat rectangular section such as that of FIG. 10 , or a cruciform section like the one in figure 11.

The diameter of the circumscribed circle C of a bristle is between 3/100 mm and 18/100 mm.

The first group of bristles 3 constitutes from 5 to 95% relative to the total number of bristles of the brush, while the second group of bristles 4, or all of the other groups, is constituted by the complement, that is to say say 95 to 5% based on the total number of hairs.

An example of a brush, with two groups of bristles of different material and with a different section shape, was produced with 50% bristles in Rilsan FAC (horseshoe section) and 50% bristles PA6.12 with full circular section , the diameter of the circle circumscribed in the sections of the bristles being 8/100 mm.

The section of the bristles may include at least one capillary groove, not shown in the drawing.

The length L (Figure 2), the bristles protrude beyond the end of the rod 5, or apparent length of the bristles, is advantageously between 12 and 30 mm. In the case of a housing 9 with a circular section, the diameter of the section of the housing can be approximately 2 mm. With a length L of approximately 13 mm and bristles with a diameter of 8/100 mm, the diameter d (FIG. 2) of the large base of the plume of bristles of the brush is greater than 4 mm, while in similar conditions, a conventional brush would have a smaller end diameter d , for example of the order of 2.5 to 3 mm.

The end of the brush may be straight, orthogonal to the axis of the rod as illustrated at 11 in FIG. 12, or may have a convex curved shape 12 as illustrated in FIG. 13. According to another possibility, the end of the brush can be cut along a plane 13 inclined with respect to the axis of the rod, as illustrated in FIG. 14.

To solve the problem of the invention, according to a second solution, one can use only the particular shape of the housing 9. In this case the bristles, forming a tuft, are fixed to the end of the rod 5 by engagement of the tuft bristles in the housing 9. The bristles 3, 4 may not be folded in half about halfway. The housing 9 has a flared shape 9b, the large base of which is located at the end of the rod 5. This shape 9b gives an airy and spreading brush tuft with relatively large spaces between the bristles, favorable for good capillarity for the varnishes whose viscosity can vary over a wide range.

In addition, the cross section of the end of the rod 5 can have any shape. It can, for example, be round, square, rectangular, triangular, oval or cruciform.

In particular, the housing 9 can be in the form of a truncated cone, pyramid, funnel; it can also be cylindrical with a shoulder defining an area of diameter larger than the bottom area 9a of the housing where the implantation of the tuft takes place.

According to the second solution, the bristles 3, 4 can be identical or different. They are made in particular of synthetic or natural material. The natural material can normally be chosen from natural bristles, in particular of animal origin. The synthetic material can be chosen from the group formed by polyamides, polyesters, polyether-block amides, polyethylenes, polytetrafluoroethylenes, polyvinylidene fluorides, polyacetals, polyethylene terephthalates.

Preferably, bristles are used whose diameter is chosen from 11 hundredths to 40 hundredths of a millimeter, and preferably from 14 hundredths to 17 hundredths of a millimeter. The hairs are preferably hollowed out.

It is possible to incorporate into the material of the hairs adjuvants modifying the surface state and the surface tension.

The mixed bristles of the brush can be straight or wavy. The bristles can be ground or tapered. The brush can have bristles of different levels.

• une différence de tension superficielle entre les poils des différents groupes ;
• un écartement des poils plus important et donc une capillarité améliorée et une rétention plus importante ce qui conduit à une plus grande autonomie.

A brush according to the invention has:

• a difference in surface tension between the hairs of the different groups;
• greater hair separation and therefore improved capillarity and greater retention, which leads to greater autonomy.

Such a brush can apply liquids from the consistency of alcohol to creamy consistency. In other words, such a brush can apply liquid products whose viscosity varies within a range of approximately 1.2 to 3500 cps.

The brushes of the invention will make it possible to develop varnish compositions having viscosities greater than the conventional viscosities generally between 200 to 400 cps. In particular, it will be possible to develop water-based varnishes having a viscosity of around 600 cps.

In addition, the capabilities of the new brush make it possible to apply the varnish without having to shake the bottle containing this varnish beforehand.

Currently, when applying a nail varnish, it is desirable to shake the bottle before use so as to modify the thixotropy. Indeed, a classic nail polish in a state of rest is generally too viscous (for example viscosity of 2000 cps) for a good application with the classic brushes; after shaking, the viscosity of conventional nail polish is in a range of about 300 to 400 cps, acceptable by conventional brushes.

A brush according to the invention can accept the viscosity (approximately 2000 cps) of a conventional varnish in the rest state, so that it is not necessary to shake the bottle of varnish before use.

Claims (21)

1. Brush for applying nail varnish, or the like, comprising bristles forming a tuft (2), obtained from a bundle (7) of substantially parallel bristles, folded in half approximately halfway down. , the bristles being fixed to the end of a rod (5) by engagement, with clamping, of the folded part (8) of the tuft of bristles in a housing (9) opening at the end of the rod (5), the bristles having sections admitting a circumscribed circle (C) of constant diameter, characterized in that the bristles (3, 4) of the tuft (2) are chosen from at least two groups, the bristles (3 ) of a group being arranged to have a mechanical flexural behavior different from that of the bristles (4) of the other group so that, when folding and tightening the different groups of bristles, these groups give a tuft ( 2) an airy and spreading brush with relatively large spaces ( i ) between bristles (3,4), favorable for good no capillarity for varnishes whose viscosity can vary over a wide range. 2. Brush according to claim 1, characterized in that the bristles (3) of a group are made of a material different from the bristles (4) of another group, these different materials having different coefficients of elasticity causing mechanical behavior different from the groups of bristles, the coefficient of elasticity of the material of a bristle (3) of a first group varying from 10% to 200% relative to the coefficient of elasticity of the material of a bristle (4) from another group. 3. Brush according to claim 1 or 2, characterized in that the bristles (3) of one group have a shape of cross section different from that of the bristles (4) of another group, these differences in shape leading to differences in flexural strength. 4. Brush according to one of the preceding claims, characterized in that the first group of bristles (3) consists of 5 to 95% of the total number of bristles of the brush, the second group (4), or all of the other groups, being constituted by the complement, namely 95 to 5% of the total number of hairs. 5. Brush according to one of the preceding claims, characterized in that the most flexible bristles are made of polyamide, or block-ether polyamide or polyester elastomer. 6. Brush according to one of the preceding claims, characterized in that the material used for the less flexible bristles is chosen from the group: Rilsan, polyamide, poyethylene, tetrafluoroethylene, polyvinylidene fluoride, polyacetate, polyethylene terephthalate. 7. Brush according to any one of the preceding claims, characterized in that the housing (9) of the rod (5) has a flared shape whose large base is located at the end of the rod (5). 8. Brush according to claim 7, characterized in that the flared shape is frustoconical of revolution. 9. Brush for applying nail varnish, or similar product, comprising bristles forming a tuft (2) fixed to the end of a rod (5) by engagement of the tuft of bristles in a housing (9 ) opening at the end of the rod (5), the bristles having cross sections admitting a circumscribed circle (C) of constant diameter, characterized in that said housing (9) opening at the end of the rod (5) has a flared shape (9 b ) whose large base is located at the end of the rod, this shape giving a tuft (2) of an airy brush spread out with spaces ( i ) between the bristles ( 3, 4) relatively large, favorable for good capillarity for varnishes whose viscosity can vary over a wide range. 10. Brush according to claim 9, characterized in that the cross section of the end of the rod has a shape taken from the group of the following shapes: round, square, rectangular, triangular, oval, cruciform. 11. Brush according to claim 9 or 10, characterized in that the housing has a shape chosen from the group of the following shapes: truncated cone, truncated pyramid, funnel, cylindrical with a shoulder defining an area of diameter greater than the bottom area of the accommodation where the tuft implantation takes place. 12 Brush according to one of claims 9 to 11, characterized in that the bristles are identical. 13. Brush according to one of claims 9 to 12, characterized in that at least part of the bristles is made of natural material, especially chosen from natural bristles, in particular of animal origin. 14. Brush according to one of claims 9 to 13, characterized in that at least part of the bristles is made of synthetic material chosen from the group formed by polyamides, polyesters, polyether-block amides, polyethylenes, polytetrafluoroethylenes, polyvinylidene fluorides, polyacetals, polyethylene terephthalates. 15. Brush according to one of the preceding claims, characterized in that the area (8) folded bristles (3, 4) is held by a clip (10) forcibly pressed into the housing (9) of the rod ( 5). 16. Brush according to one of the preceding claims, characterized in that the length (L) along which the bristles of the brush protrude beyond the end of the rod (5) is between 12 and 30 mm, limits included. 17. Brush according to one of the preceding claims, characterized in that the diameter of the circle (C) circumscribed in the cross section of a bristle is between 3/100 mm and 18/100 mm, limits included. 18. Brush according to one of the preceding claims, characterized in that the shape of the cross section of a bristle of a group is chosen from the following shapes: solid circular, hollow circular, horseshoe, V , flat, cruciform, or with capillary grooves. 19. Brush according to one of the preceding claims, characterized in that adjuvants which modify the surface state and the surface tension are incorporated in the material of the bristles. 20. Brush according to any one of the preceding claims, characterized in that the bristles have a selected diameter of 11 hundredths to 40 hundredths of a millimeter. 21. Brush according to any one of the preceding claims, characterized in that the bristles are hollowed out.

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