EP0937424B2 - Brush for nail varnish or the like - Google Patents

Description

The invention relates to a brush for applying nail polish, or a similar product, of the kind of those which comprise bristles forming a tuft, attached 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 makes it possible, with conventional nail polish compositions, to make a precise and rapid application of the varnish. In particular, with such a brush, it is no longer necessary to plunge the brush many times in the container to make the makeup of a nail because the product load taken with the brush is relatively high.

Conventional nail polish compositions currently in use have viscosities of about 200 centipoise to 400 centipoise. However, developing nail polish compositions have higher viscosities, especially about 600 cps (centipoise). Even more viscous compositions are also contemplated.

It has been found, in tests, that the known nail polish 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 object of the invention is, above all, to provide a nail polish brush which, even with high viscosity lacquers, in particular greater than 600 cps, allows the product to be applied under good conditions, while being usable for the application of classic nail polish.

The invention also aims to provide a brush which, while meeting the requirement stated above, remains a simple and economical manufacturing, and a conventional use.

To solve this problem, it is possible to use a housing of particular shape: the invention therefore relates to a brush according to claim 1.

A brush according to the invention, for applying nail polish or a similar product may comprise bristles forming a tuft, obtained from a substantially parallel bundle of bristles, folded in half about halfway along the length, the bristles being fixed at the end of a shank by clampingly engaging the folded portion of the tuft of bristles into a housing opening at the end of the shank, the bristles having cross-sections having a circumscribed circle of constant diameter , the bristles of the tuft being able to be chosen from at least two groups, the bristles of a group being arranged to have a mechanical behavior with the flexion different from that of the bristles of the other group so that, during the folding and the tightening of the different groups of bristles, these groups give a brush tuft aerated and spread with spaces between relatively large bristles, favorable to a good capillarity for varnishes whose viscosity pe Can vary over a wide range.

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

According to another possibility that can be combined with the previous one, the hairs of one group have a cross-sectional shape different from that of the hairs of another group, these differences in shape leading to differences in resistance to flexion, 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, consisting of the complement namely 95 to 5% relative to the total number of bristles.

The brush may comprise a third group of different hairs whose number may vary from 90% to 10% relative to the total number of bristles of the brush.

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

The tuft of the brush may be obtained from a substantially parallel bundle of bristles, folded in half about halfway along the length, the folded portion of the tuft of bristles being engaged with interference in the housing of the stem.

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

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

The hairs may be the same or different. They are made in particular synthetic or natural material. The natural material may be normally selected from natural bristles, preferably of animal origin. The synthetic material may be chosen from the group formed by polyamides, polyesters, polyether-block-amides, polyethylenes, polytetrafluoroethylenes, polyvinylidene fluorides, polyacetals and 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 able to apply, in particular, varnishes whose viscosity is in the range of 200 to 2000 cps, inclusive limits. In practice, the brush of the invention allows for a correct application of liquid product whose viscosity may vary within a range of from about 1.2 to about 3500 cps.

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

The length at which the bristles of the brush protrude beyond the end of the shank may be between 12 and 30 mm inclusive.

The diameter of the circle circumscribing the cross section of a hair is between 3/100 mm and 18/100 mm, limits included; this diameter is the same for all the hairs 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, flat, cruciform, or provided with capillary grooves.

Adjuvants modifying the surface state and the surface tension may be incorporated into the material of the bristles of the brush.

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

Figure 1 of this drawing is an elevational view of a nail polish 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 hair bundle for the manufacture of the brush.

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

Figure 5 is a schematic view, on a larger scale, of the 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 forms for the end 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, there can be seen a brush 1 for the application of nail polish comprising a tuft 2 of bristles 3, 4 attached to the end of a rod 5, and oriented substantially in the direction axial axis. 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 an operating member of the brush; it also serves as a plug for, 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 substantially parallel bristles 3, 4, folded in two approximately at mid-length as illustrated in FIG. 4. The tuft 2 is fixed at the end of the rod 5 by engagement, with tightening, of the folded portion 8 (see Figure 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 with 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 a group are arranged to have a different mechanical bending behavior than that of the bristles 4 of the other group so that, during folding and tightening of the different groups of hairs, these groups give a tuft 2 airy and spread.

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

Aeration and spreading of the tuft 2 of bristles result from the combined effect of the folding of the bundle 7 substantially at mid-length and engagement with clamping of the folded portion 8 in the housing 9. The cooperation of an area of the tuft 2 with the walls of the housing 9, and the clamping of this tuft in the housing, are involved in formation of a plume of a tuft 2.

Generally, the tuft 2 is made as illustrated in FIGS. 3 and 4, by placing the average 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 approximately halfway length of the beam 7 and is pressed into the housing 9 causing the folding of the bristles 3, 4 which bear against the edge of the housing 9. During this operation, the clip 10 folds so as to tighten the bristles and is engaged by force in the rod 5.

The clip 10 is made from a metal wire, bent in a U, whose section can be circular, rectangular flat, 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 base region 9 has (Figures 2 and 15) of the housing 9, where appropriate implantation of the staple, can be circularly cylindrical, while the upper portion 9b of the housing located beyond this cylindrical area a flared, frustoconical shape of revolution whose large base is located at the open end of the housing 9. The tuft 2 of the brush, implanted in such a housing, has a truncated cone shape with a substantially circular base.

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

FIG. 17 illustrates an advantageous variant of the shape of the housing 9. In the bottom of the housing, there is a cylindrical portion of revolution 9 " a . The upper flared portion 9 " b has a substantially flattened rectangular shape, the long sides of which are curved to have a concavity towards the outside, the end of the rod 5 therefore has two concave faces c forming, in a way, a channel feed for the flow of the product from the stem to the tuft of the brush.

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

To ensure a different mechanical behavior to the bending of the two groups of bristles 3 and 4, according to a first possibility, one chooses for each group of bristles 3, 4 different materials having different elasticities. 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% with respect 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 to bending.

The most flexible bristles may be made of a polyamide, for example the polyamide known under the trade name Tynex from Dupont de Nemours, or polyamide block-ether, or polyester elastomer. The less flexible bristles may be made of a material selected 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 made with 8/100 mm diameter bristles with 50% Rilsan bristles and 50% PA6.10 bristles (6.10 polyamide).

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

Another example corresponds to 30% of PET (polyethylene terephthalate) bristles with a diameter of 10/100 mm and 70% of PA6.12 bristles 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 shown in Figure 6, while the more flexible bristles 4 will have a hollow circular section such as that of Figure 7, the outer diameter of the bristles being the same.

Other forms of sections may 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 rectangular flat section such as that of FIG. 10. , or a cruciform section such as that of Figure 11.

The diameter of the circumscribed circle C of a hair 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 the other groups, is constituted by the complement that is to say say 95 to 5% of the total number of hairs.

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

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

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

The end of the brush may be rectilinear, 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. Alternatively, the end of the brush may be brush may be cut along a plane 13 inclined relative to the axis of the rod, as shown in Figure 14.

To solve the problem of the invention, it is possible to use the particular shape of the housing 9. In this case, the bristles, forming a tuft, are fixed to the end of the shank 5 by engaging the tuft of bristles in the housing 9 The bristles 3, 4 may not be folded in half about mid-length. The housing 9 has a flared shape 9b whose large base is located at the end of the latige 5. This shape 9b gives an airbrush tuft and spread with spaces between the relatively large bristles, favorable to good capillarity for the varnish whose viscosity may vary over a wide range.

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

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

The bristles 3, 4 may be the same or different. They are made in particular synthetic or natural material. The natural material may be normally selected from natural bristles, in particular of animal origin. The synthetic material may be chosen from the group formed by polyamides, polyesters, polyether-block-amides, polyethylenes, polytetrafluoroethylenes, polyvinylidene fluorides, polyacetals and 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.

Hairs of surface modifying and surface tension modifying additives may be incorporated into the bristles.

The mixed bristles of the brush may be straight or wavy. The hairs can be ground or tapered. The brush can have hairs 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 an embodiment of the invention presents:

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

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

The brushes of the invention will make it possible to develop lacquer compositions having viscosities greater than the conventional viscosiums generally ranging from 200 to 400 cps. In particular it will be possible to develop water-based coatings having a viscosity of about 600 cps.

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

Currently, when applying a nail polish, it is desirable to shake before use the bottle so as to modify the thixotropy. Indeed, a conventional nail polish in a state of rest is generally too viscous (for example viscosity of 2000 cps) for good application with conventional brushes; after agitation, the viscosity of the 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 (about 2000 cps) of a conventional varnish in the state of rest, so that it is not necessary to stir the vial of varnish before use.

Claims (20)

1. Brush for the application, to the nails, of a nail varnish, or of a similar product to the nails, which includes bristles forming a tuft (2) which are fixed at the end of a rod (5) by engagement of the bristle tuft 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, and being directed substantially along the axial direction of the rod, characterized in that the region of the opening of the housing (9) situated at the end of the rod (5) has a larger cross-section than the region of the bottom of the said housing (9), so that the tuft (2) of the brush is open to the air and spread out and has relatively large spaces (1) between the bristles (3, 4), this being favourable for good capillary action for products that need to be applied whose viscosity may vary over a wide range.
2. Brush according to Claim 1, characterized in that the region of the bottom of the housing (9) includes a cylindrical portion.
3. Brush according to one of Claims 1 and 2, characterized in that the region of the opening of the housing (9) includes a cylindrical portion,
4. Brush according to Claims 2 and 3 taken simultaneously, characterized in that the housing (9) comprises two cylindrical portions connected by a shoulder.
5. Brush according to Claim 2, characterized in that the housing (9) has the shape of a funnel, the region of the opening (9b) of the said housing (9) having a conical flared shape and being connected to the bottom region (9a) by its small base, the said bottom region (9a) being cylindrical.
6. Brush according to Claim 1, characterized in that the housing has the shape of a cone frustum or pyramid frustum.
7. Brush according to one of Claims 1 to 4, characterized in that the cross-section of the region of the opening of the housing (9) has a shape taken from the group of the following shapes: round, square, rectangular, triangular, oval, cruciform.
8. Brush according to one of Claims 1 to 7, characterized in that the bristles are identical,
9. Brush according to one of Claims 1 to 7, characterized in that at least part of the bristles is made of bristles of natural material.
10. Brush according to Claim 9, characterized in that the natural material is chosen from natural silks, in particular of animal origin.
11. Brush according to one of Claims 1 to 7, 9 or 10, characterized in that at least part of the bristles is made of bristles of a synthetic material, chosen from the group formed by polyamides, polyesters, polyether-block-amides, polyethylenes, polytetrafluoroethylenes, polyvinylidene fluorides, polyacetals, polyethylene terephthalates.
12. Brush according to one of Claims 1 to 11, characterized in that the tuft (2) of bristles is made from a bundle (7) of bristles folded in two, the folded part (8) of the tuft (2) being held in the bottom region of the housing (9).
13. Brush according to Claim 12, characterized in that the folded region (8) of the bristles (3, 4) is held in place by a staple (10) forcibly pushed into the housing (9) of the rod (5).
14. Brush according to one of Claims 1 to 13, characterized in that the length (L) by which the bristles of the brush project beyond the end of the rod (5) is between 12 and 30 mm, limits inclusive.
15. Brush according to Claim 11, characterized in that the shape of the cross-section of a bristle of synthetic material is chosen from the following shapes: solid circular, hollow circular, horseshoeshaped, V-shaped, flat, cruciform, or one equipped with capillary grooves.
16. Brush according to Claim 15, characterized in that the diameter of the circle (C) circumscribing the cross-section of a bristle is between 3/100 min and 18/100 min, limits inclusive.
17. Brush according to one of Claims 1 to 16,
    characterized in that additives modifying the surface finish and surface tension are incorporated into the material of the bristles.
18. Brush according to one of Claims 9 to 11 characterized in that the bristles have a diameter chosen from 11/100 to 40/100 mm.
19. Brush according to Claim 11, characterized in that the bristles are hollowed.
20. Use of a brush according to one of claims 1 to 19, for the application, to the nails, of a nail varnish or of a similar product.

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