EP0486329B1 - Mascara brush and its method of manufacture - Google Patents

Description

The invention relates to a brush for applying a cosmetic product of the kind which includes a multitude of bristles implanted transversely in a core, in particular formed by twisted metal turns, at least part of the bristles being formed. by a statistical mixture of hairs of relatively large cross section and hairs of relatively small cross section.

Such a brush is more particularly suitable for applying mascara to the eyelashes, but can also be used for treating the hair, for example for dyeing it.

Such brushes are generally used for removing a makeup product or the like from a container fitted with a wringer which the brush passes through at its outlet. When the brush is equipped with bristles of relatively small section, little product remains on the bristles during spinning and the resulting makeup is weak. In addition, when the bristles of small cross section are tight, the eyelashes cannot enter between these hairs which lie on top of each other during makeup. On the other hand, the suppleness of these hairs gives a pleasant character to the makeup while avoiding irritation of the skin. The flexibility also makes it possible to standardize the deposit of product.

To reinforce the make-up effect, it has been thought to equip the brush with bristles of larger section which remain more loaded with product after wringing, in particular if they are provided with capillary grooves.

FR-A-2 637 472 describes such a brush in which bristles of large section are mixed with bristles of small section, the length of the latter being greater than that of the bristles of large section. The bristles of relatively large section allow to take a sufficient quantity of product to deposit it on the eyelashes and to comb and smooth them, while the bristles of small section allow to give softness and separation to the brush equipped with large bristles .

However, the makeup obtained with such a brush is relatively natural and it is hardly possible to make very different makeup from each other because a certain uniformity comes from the effect of the soft bristles which form a fluff beyond the end of large hairs.

The object of the invention is, above all, to provide a brush for applying a cosmetic product which makes it possible to obtain very different makeup effects.

To achieve this object, in accordance with the invention, a brush of the kind defined above is characterized in that in at least one zone of the brush the bristles of relatively large section have a length greater than the bristles of relatively small section and that at least the outer ends of the bristles of small section have a bulge.

Preferably, the end of the bristles of relatively large section also includes a bulge.

Thus, according to the invention, the bristles of relatively large section are prominent and exert a more marked action in terms of make-up, while the bristles of small section continue to play a non-negligible role in the distribution of the product. Increasing the role of section hairs significant does not cause any particular irritation of the skin, in particular thanks to the bulges provided at their outer ends.

The bristles of large section generally have, over the entire extent of the brush, a length greater than the bristles of small section, and a bulge at their end.

However, this arrangement may only be provided over a fraction of the length of the brush or over an angular fraction of the cross section; in the remaining part of the brush, the bristles of small section have a length equal to that of the bristles of large section.

The difference in cross section between the bristles causes a difference in flexibility, which is greater for bristles of small cross section

The bristles can be formed from nylon or polyester fibers, the bristles of small section having a diameter less than 10 / 100th of a millimeter (0.10 mm), while the large bristles have a diameter equal to or greater than 10 / 100th millimeter (0.10 mm) and generally less than 30 / 100th of a millimeter (0.30 mm).

The bristles, rigid or flexible, are preferably of synthetic origin.

Preferably, the shape of the section of the bristles, in particular of the large bristles, is of one of the following types: solid circular, hollow circular, multilobed, in particular trilobed, or in horseshoe.

The outer ends of the large bristles can be located on a first surface having a contour different from a second surface on which the ends of the bristles of small cross section are located, the first surface being located on the outside. of the second surface.

The contours of the first and second surfaces, in section perpendicular to the brush core, can be formed by circles, concentric or eccentric.

• on réalise une ébauche de brosse avec des poils de section transversale importante et des poils de faible section ayant la même longueur dans une section transversale orthogonale à l'axe de la brosse, les gros poils étant agencés pour présenter une résistance à la chaleur supérieure à celle des poils de faible section ;
• on expose au moins une partie de la brosse à une source de chaleur suffisamment forte pour provoquer une fusion et une rétraction des extrémités des poils, les poils de section transversale importante subissant une rétraction plus faible que les poils de faible section, des renflements dûs à la fusion de la matière des poils se formant aux extrémités des gros poils et/ou des poils de faible section.

The invention also relates to a method of manufacturing a brush as defined above, this method being characterized by the following steps:

• a brush blank is produced with bristles of large cross section and bristles of small section having the same length in a cross section orthogonal to the axis of the brush, the large bristles being arranged to have a heat resistance greater than that of bristles of small section;
• exposing at least part of the brush to a source of heat strong enough to cause fusion and retraction of the ends of the bristles, the bristles of large cross-section undergoing a lesser retraction than the bristles of small section, bulges due to the fusion of the material of the bristles forming at the ends of the large bristles and / or of the bristles of small section.

Preferably, the brush is placed on means suitable for rotating it around its axis at a high speed.

The heat source is advantageously chosen from all of the following sources: hot air source, infrared source, electrical resistance.

The brush can be chosen from brushes of the metal core type or of the fully injected type. The brush blank may have an eccentric core, but is preferably concentric.

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 is in no way limiting.

Figure 1 is a schematic side view of a brush according to the invention.

Figure 2 is a view along line II-II of Figure 1 on a larger scale.

Figure 3 is a view similar to Figure 2 of an alternative embodiment in which only an angular sector of a cross section has bristles of different lengths while the rest of the cross section has bristles of the same length, of which the ends are not swollen.

Figure 4, finally, is a diagram illustrating a method of manufacturing a brush according to the invention.

Referring to the drawings, more particularly to Figures 1 and 2, one can see a brush 1 for the application of a cosmetic product, in particular for the application of mascara to the eyelashes, which comprises a multitude of bristles implanted transversely in a core 2 formed in particular by twisted metal turns. This core is integral with a handle 3 for gripping the brush. The bristles of the brush are formed by a statistical mixture of bristles of relatively large cross section 4 and bristles of small cross section 5.

Statistical mixing means a mixture in which the distribution of bristles of large cross section and of small cross section is substantially regular for each type of bristle, in particular in a cross section, over a complete revolution.

The bristles of relatively large section 4 have a length greater than the bristles of small section so that in a cross section of the brush, as shown in Figure 2, the outer ends of the large bristles 4 protrude beyond the outer ends of the bristles of small section 5. The outer end of a bristle of relatively large section is provided with a bulge 6 of substantially spherical shape.

To make the drawing clearer, for the sake of simplification, in FIG. 1, the bristles of small section 5 have been placed, in the axial direction, between the large bristles. It is clear however that in the same cross section, that is to say at the same level in the axial direction of the core 2, one can find large bristles 4 and bristles of small section 5.

The outer end of the bristles of small section 5 also includes a substantially spherical bulge 7.

The difference in cross section between the bristles 4 and 5 causes a difference in flexibility. Flexibility is more important for bristles of small cross-section.

For example, synthetic bristles are used, made of the same material, formed of nylon or polyester fibers, the bristles of small section 5 having a diameter less than 10 / 100th of a millimeter, while the large bristles 4 have a diameter equal to or greater than 10 / 100th of a millimeter and generally less than 30 / 100th of a millimeter.

It should be noted that the bristles of the brush 1, whether rigid or flexible, are generally of synthetic origin, but the choice of raw material may be different.

The section of the bristles 4, 5 may have variable forms, and in particular belonging to one of the following types: solid circular forms, hollow circular forms, multilobed forms in particular three-lobed, or in horseshoe. This type of bristles is described for example in FR-A-2 607 372 and FR-A-2 607 373. Hairs which are hollow or have capillary grooves are advantageous because they serve as a reservoir for the product to be sampled, in particular mascara.

A brush was produced using a mixture of synthetic bristles of different diameter and cross-sectional shape, for example 8 / 100th of a millimeter for bristles of small full circular section, and 17 / 100th of a millimeter for large bristles of cross-section .

The brush 1 may have, along its length, a defined profile contour, for example a frustoconical contour as shown in FIG. 1. The dimensions of the large bristles 4 and of the bristles of small section 5 progressively decrease from the handle 3 towards the tip of the brush but, at the same cross section, the large bristles retain a length greater than that of bristles of small section.

The outer ends of the bristles of large section 4 are located on a first surface A having a contour different from a second surface B on which the ends of the bristles of small section 5 are located. The first surface A surrounds the surface B. In the 'example considered, the contours of these two surfaces, in section perpendicular to the axis of the core 2 of the brush, are constituted by concentric circles. However, these circles could be offset.

FIG. 4 illustrates an advantageous method of manufacturing a brush according to the invention.

In a first step, a brush blank E is produced with bristles of large section 4 and bristles of small section 5 having the same length in a cross section orthogonal to the axis of the brush. The profile, lengthwise, of the general outline that this blank is similar to that desired for the finished brush; in the example considered this profile is frustoconical, but is located beyond the finished profiles A, B.

The large bristles 4 are arranged to have a resistance to heat greater than that of bristles of small section 5. In the case where these bristles are made of the same material, the fact that the large bristles 4 have a larger cross section to give them greater resistance to heat.

Heat resistance can be varied by choosing, for example, a mixture of bristles of different diameters made of different materials having a melting point at different temperatures.

The brush blank is mounted on a lathe 8, for example by fixing the handle 3 in the mandrel 9 of this lathe, and the brush is rotated around its axis at a high speed.

This brush is exposed, parallel to its axis, and at a certain radial distance, to a heat source S which may be constituted by a source of hot air, an infrared source, or an electrical resistance. The heating setting is determined so that the ends of the bristles 4 and 5 are fused.

A hair of small section 5 will melt faster than a large hair 4 and will shrink faster and over a greater distance than the large hairs 4.

At the end of the operation, we see that the bristles of large section 4 have a length greater than that of bristles of small section 5 as illustrated in FIG. 2. In addition, each end of the bristles carries the respective bulge 6, 7 forming a kind of "rounded nail head", which gives a certain "slippery" on the eyelash, in particular to hairs with a large section, and which avoids any irritation despite the large diameter of these hairs.

The results obtained can be adjusted in terms of heights and in terms of the shape of the bulges by using a mixture of different bristles on the one hand from the point of view of the diameters of the sections and on the other hand from the point of view of the section shapes.

We can say that at a given temperature setting for the source S, at a given speed of rotation of the brush around its axis, and at a given distance from the source S to the axis of the brush, according to the variation of the percentage of bristles of one type relative to another, possibly compared to a third type of bristles, both in terms of diameter and in terms of section, as many different brushes will be obtained. In fact, the shrinkage of the bristles will always depend on the shape and diameter of each bristle and, where appropriate, on the material used for the bristles, a material whose melting point may vary.

The brushes thus produced can have infinite variations and lead to very different make-ups depending on the types of bristles mixed and implanted, the percentage of each of the different bristles and the different materials.

In addition, with the same brush, due to the prominence of the bristles of large cross section 4, it is possible to obtain a more charged makeup, and more easily modifiable according to of the brush holding by the user.

It should be noted that the presence of large bristles longer than bristles of small section, and provided at their outer ends with bulges may only be provided over part of the length of the brush 1, or over a fraction of the cross section as illustrated in Figure 3. The half cross section on the left of Figure 3 includes large bristles longer and provided at their outer ends with bulges and bristles of small cross section also provided with bulges. On the other hand, the half-section located on the right has large hairs and hairs of small section of the same length, without bulges at their outer ends. A brush conforming to FIG. 3 can be obtained by subjecting the blank mentioned above to the heat source S without rotating this blank around its axis.

Claims (10)

1. A brush (1) for the application of a cosmetic product, in particular to the eyelashes or the hair, comprising a plurality of bristles (4, 5) transversely implanted in a core (2) that is, in particular, formed by twisted metal turns, at least a proportion of the bristles being formed by a mixture of bristles with a relatively large cross-section (4) and bristles with a relatively small cross-section (5), characterized in that in at least one zone of the brush, the bristles with a relatively large cross-section (4) have a length that is greater than the bristles with a relatively small cross-section (5), and that at least the outer ends of the bristles with a small cross-section (5) have a bulge (7).
2. A brush according to claim 1, characterized in that the ends of the bristles with a relatively large cross-section (4) also have a bulge (6).
3. A brush according to claim 2, characterized in that the bristles with a large cross-section (4) have, over the whole extent of the brush, a length that is greater than the bristles with a small cross-section (5) and a bulge (6) at their ends.
4. A brush according to one of claims 1 to 3, characterized in that the bristles with a large cross-section (4) only have a length greater than that of the bristles with a small cross-section (5) over an angular fraction of the cross-section, the bristles with a small cross-section (5) having a length equal to that of the bristles with a large cross-section in the remaining portion of the brush.
5. A brush according to one of claims 1 to 4, characterized in that the bristles with a small cross-section (5) have a diameter that is smaller than 10/100ths of a millimetre, whilst the bristles with a relatively large cross-section (4) have a diameter equal to or greater than 10/100ths of a millimetre and generally less than 30/100ths of a millimetre.
6. A brush according to any one of the preceding claims, characterized in that the cross-section of the bristles (4, 5) is one of the following types: solid circular, hollow circular, multilobar, in particular trilobar or horseshoe-shaped.
7. A brush according to any one of the preceding claims, characterized in that the outer ends of the bristles with a relatively large cross-section (4) are situated on a first surface having a contour different from a second surface whereon the ends of the bristles with a small cross-section (5) are situated, the first surface being situated outside the second surface.
8. A method for the manufacture of a brush such as defined according to claims 1 to 7, characterized in that

   - a blank of the brush (1) is made with bristles with a relatively large cross-section (4) and bristles with a small cross-section (5) having the same length in a cross-section orthogonal to the axis of the brush (1), the large bristles (4) being arranged to have a greater resistance to heat than that of the bristles with a small cross-section (5);

   - that at least a portion of the brush (1) is exposed to a source of heat (S) that is sufficiently strong to produce a fusion and retraction of the ends of the bristles (4, 5), the bristles with a large cross-section (4) undergoing a smaller retraction than the bristles with a small cross-section (5), bulges (6, 7) due to the fusion of the material of the bristles being formed at the ends of the bristles with a small cross-section and of the large bristles.
9. A manufacturing method according to claim 8, characterized in that the brush (1) is disposed on means (8) that are capable of causing it to turn round its axis at a high speed.
10. A manufacturing method according to claim 8 or 9, characterized in that the heat source (S) is chosen from the set of the following sources: a source of hot air, an infrared source, an electrical resistance.

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