EP2552264B1 - Bra cup structure - Google Patents

Description

The present invention relates to a bra cup structure.

We know from the document FR 2 813 167 a bra cup structure consisting of two layers of laminated foam enclosing between them a close containing a malleable material, in this case a liquid. The foam layers can be laminated to textile layers. In addition, the document WO 00/47068 also discloses a similar structure, improved by a new choice of malleable material to garnish the pocket.

Although each of these innovations aims to create both a bra with a "push-up" effect, it remains for users to make progress in terms of comfort, invisibility, volumizing effect and upward, and freedom of movement. This is the purpose of the present invention.

To achieve this, the present invention provides a bra cup structure comprising two layers of laminated foam enclosing between them, in their lower part, a bag containing a malleable material, characterized in that the malleable material is a silicone gel charged with polymeric microspheres and crosslinked, and in that the two layers of foam are viscoelastic foam.

The Applicant has found that this particular combination of materials led to remarkable comfort properties including behavior very close to that of the flesh when pressing the structure under the fingers. Remarkably, these two materials have a shape memory: the viscoelastic foam has this shape memory by definition, and the crosslinked silicone gel, albeit malleable and thus accepting the deformations under the finger, by movement or conformation of the bust, also remembers the shape he has acquired in the mold in which he has cross-linked.

Advantageously, the malleable material is arranged for its protection in a casing or pouch constituted by two polymeric films sealed to one another, for example polyurethane. Their thickness is advantageously very low so as not to induce an effect perceptible to the touch. The thickness is preferably less than 40 μm and more preferably of the order of 35 μm. The envelope avoids the destruction of the silicone gel which is relatively fragile, by breaking its chains. The malleable silicone gel material is advantageously crosslinked in its pocket.

The malleable material has a density advantageously between 0.60 and 0.75 g / cm ³ .

The bag filled with malleable material is inserted during a molding operation (thermoforming) between at least two layers of viscoelastic foam, the density of which is advantageously between 30 and 65 kg / m ³ and advantageously of the order of 50 kg / m ³ .

The layers of viscoelastic foam are preferably laminated to a textile material, such as a polyester or polyamide mesh, before they are bonded together, this textile material being disposed towards the outside of the cup.

Advantageously, the weight of silicone gel in the bag is very small, preferably less than 10 grams, advantageously substantially between 7 and 9 grams.

The shape of the pocket depends on the size of the bra for which it is provided, but it is generally of elongated shape and more particularly substantially elliptical, with a major axis between 8 and 15 cm and a small axis between 4, 5 and 7 cm. Its average thickness is preferably between 2 and 3 mm.

Particularly advantageously, the standardized force of 25% depression in the bonnet of the invention, in the portion where the pocket is located, is between about 2 and 3 N, and the standardized force 65% depression. at the same place is between about 15 and 30 N.

• en Figure 1, une structure de bonnet conforme à l'invention vue de face ;
• en Figure 2, la section II-II de la structure de bonnet de la figure 1en coupe verticale ;
• en Figures 3 et 4, deux variantes de forme de poche de matière malléable.

Other features and advantages of the invention will emerge from the following description of an exemplary embodiment. Reference will be made to the accompanying drawings showing:

• in Figure 1 , a cap structure according to the invention seen from the front;
• in Figure 2 , section II-II of the cap structure of the figure 1 in vertical section;
• in Figures 3 and 4 , two variants of pocket shape of malleable material.

A thermoformed cup structure 1 has, after thermoforming, a substantially hemispherical shape, having a depth H of the order of 70 to 75 mm. It is composed of two layers laminated visco-elastic foam 2 and 3 which enclose with each other, at their lower part, a bag of malleable material 4, formed by two polyurethane films 5, 6 welded to their edges and enclosing a gel of crosslinked silicone. As we see on the figure 1 the material pocket 4 has a substantially almond-shaped shape bounded by the dashed curved line which marks the upper edge 7 of the pocket 4; the pocket 4 essentially occupies the lower part of the cup, substantially below half of the cup and preferably on its lower third. In section, as we see on the figure 2 , the bag of material 4 has a generally weakly biconvex shape (substantially flat) but tapered at the edges, the shape of the pocket can change during the wear in contact with the chest and because of the movements. The thickest cup, at the thickest part of the pocket 4, is of the order of 10 to 14 mm (pocket and layers of foam). The layers of viscoelastic foam 2 and 3 are bonded, before assembly, to a fine textile layer 11 and 12, for example polyester, which facilitates their maintenance and handling, and avoids problems of removal of the material during the molding.

The malleable material, in one exemplary embodiment, is based on a two-component silicone gel RTV2 type (crosslinking at room temperature), for example of the Silbione® type marketed by Bluestar Silicones. The silicone gel has a dynamic viscosity before crosslinking which is for example between 6000 and 250,000 mPa.s at 25 ° C. Its density before introduction of the load is of the order of 1 to 1.5 g / cm ³ . A charge of polymeric microspheres is mixed with the silicone gel, for example microspheres of the Expancel® brand marketed by Akzo-Nobel. These expanded microspheres of acrylic-based polymer, 20 to 80 μm in diameter, are mixed with the gel so that the density of the material after mixing is between 0.60 and 0.75 g / cm ³ . In one exemplary embodiment, the microspheres form from 1 to 3% by weight of the mixture.

The pouch 4 is manufactured in the following manner. Two thin films 5, 6 of polyurethane were previously assembled to form an almond-shaped envelope, with edges for example heat-sealed, and having an opening through which the mixture of the two components of the silicone gel is poured into the envelope. The opening is closed, the assembly is optionally placed in a metal mold having the definitive shape of the pocket and the whole is crosslinked by means of a heat treatment. We thus obtain a "pad" or pocket 4 of malleable material. The dimensions of the pocket depend on the size of the bra to which it is applied, but it advantageously measures between 8 and 15 cm along its major axis and between 4.5 and 7 cm along its minor axis, and its thickness, relatively uniform. outside the edges, is between 1.5 and 5 mm, and preferably between 2 and 3 mm. According to the invention, the filling of the envelope is limited, preferably to less than 10 grams, so that the filled envelope is not hard but on the contrary remains flexible, foldable, and allows the momentary depression of a finger after crosslinking. In practice, an envelope 4 in the shape of an almond or ellipse of approximately 10.5 cm x 5.5 cm, with an average thickness of 2.6 mm, filled with 9 g of silicone gel, has been satisfactory .

We will now describe the manufacture of the cup from viscoelastic foam layers 2,3 laminated to their textile layer 11, 12. Foam layers 2, 3 in the non-thermoformed state have a thickness of about 6 mm .

For the manufacture of the cup structure 1, the outer foam layer 2, 11 is first thermoformed in a mold adapted to the shape of the cup, for example between 1 and 2 minutes at a temperature in the range of 160 to 190 ° C, for example 180 ° C, by adjusting the spacing of the two parts of the mold to allow compression / uniform molding of this layer 2, 11.

In a second step which can be performed in the same mold or in a similar mold, the inner viscoelastic foam layer 2, 11 which has just been thermoformed is then laminated together to the second layer 3, 12 which does not has not been yet, for example by coating the two layers of foam facing glue, advantageously a water-based glue. We place between the two sides to laminate a mask temporary preventing bonding at the area that will later be occupied by the pocket and an adjacent area communicating with the edge of the layers. This mask may comprise a foam pad substantially occupying the surface that will occupy the pocket. The spacing between the male and female parts of the mold is adjusted to allow the compression of the two layers, and the thermoforming is performed for example 40s at the same temperature as before. Following this step, the two layers 2 and 3 are glued to their interface 8, except in the zone where the pocket 4 must be inserted and in a passage allowing access to this zone. The mask and the foam cushion are removed. The combined thickness of the two layers 2, 3 thermoformed is between 2 and 3 mm.

In a third step, the pocket 4 and / or the zone between the foam layers 2 and 3 are inserted into the pocket and the pocket 4 is placed in this zone. The passage left open is also sealed. Fixing is ensured by the heat and the pressure in the mold, for example during 40s at 180 ° C.

The set can be cut to the exact shape that must be the cup, as shown in Figures 1 and 2 .

The thermoforming mold may for example be of the type described in the document GB 1,577,099 or the document FR 2,906,111 in the name of the Claimant.

During the thermoforming of the structure 1, a compressed edge 9 has been formed on the lower half of the hemispherical cap which will allow the possible insertion of an armature and the connection of the cap with the substantially flat brass bra (by sewing, welding or gluing) and at the upper part of the cap an upper lug 10 which will be used for the connection with the bra strap. The border 9 may be formed either as shown in the plane of the base of the cup and facing outwards, or on the contrary in the extension of the cup, according to the preparation technique envisaged.

Once the cup structure 1 thermoformed, we can use it in a conventional bra, where it is assembled by conventional clothing. The structure is then advantageously covered on the outside by a decorative textile material, possibly a lace, while the inner surface 12 made of polyester can be used directly as the inner textile surface of the finished bra.

One could also according to a principle that does not go beyond the invention manufacture directly by thermoforming the entire bra, according to known techniques for multilayer bras. In this case, the pocket 4 is arranged in locations between layers of viscoelastic foam laminated to textile layers and already having substantially the shape of the final bra (cups, separator, basque and back).

Various experiments were carried out to determine the essential parameters which led to a result judged particularly satisfactory by the users. The penetration force for 25% and 65% compression was measured on different samples according to a procedure standardized by ASTM D3574-95 but adapted to the subject of the invention, so as to enable the realization of tests on finished products (ie the bra cup). The size of the Zwick 22.5 test dynamometer machines with a force sensor of 1000 N, namely a 150 mm x 150 mm perforated square bottom plate and a 45 mm high circular plate, were therefore essentially adapted. of diameter.

The samples are prepared by marking the area to be measured, in the middle of the pocket area 4. The sample is first compressed twice to 75% of its thickness, at a speed of 4 mm / s and then left to rest for 6 minutes. The indentation force deflection (IFD) compressive strength measurements at 25% and 65% are made by compressing the sample at a speed of 0.85 mm / s over 25% and then 65% of its thickness. the force being measured after a rest of 60s.

The results of 23 measurements are reported in the attached table where the tests carried out on cups prepared according to the invention were made bold by juxtaposing layers of viscoelastic foam and a bag of silicone gel, with various variations. as to the nature of the silicone gel, its weight, and the thickness of the polyurethane film. The foam is unchanged in these samples with a density of 50 kg / m ³ . The other tests were made on commercial hats of different structures supposed to bring already a comfort and a maintenance in the chest.

These results were tested by touch and wear tests which revealed that the structures according to the invention were perceived in a much more favorable manner than the others, with the exception of the sample 22 which was considered too hard, probably due to an excessive combination of weight and pocket thickness of silicone and polyurethane film thickness, and to a lesser extent, sample 19 also with a thickness of 40 μm of polyurethane film. Finally, it has been found that the satisfactory samples of the invention have the remarkable property of having a 25% IFD measurement substantially between 2 and 3 N and a 65% IFD measurement of substantially between 15 and 25%. 30 N for cups of average size. This combination gives a soft felt remarkable to the touch and wear, and provides a cap with high adaptability, adjusting perfectly to the shape and the particular size of the breast to provide a round chest and reassembled. This comfort lasts throughout a day wearing and allows great freedom of movement: the silicone pocket can deform and adapt to the chest in motion, filling hollow spaces permanently.

The measurements reported above were carried out on cups of average size (90B France / 75B Europe). For cups of different sizes, the shape of the bag, its dimensions and its weight in particular, may differ, which may influence the values of the measurements. The figure 3 represents a pocket 4 adapted to a small cap (7A Europe), more compact in shape with a truncated end relative to the basic shape, about 90 mm by 47 mm. The figure 4 represents a pocket 4 adapted to a larger cup (80D Europe), more elongated form relative to the basic shape, about 120 mm by 30 mm. Comparative table Sample IFD25% (N) IFD65% (N) comments 1 1.71 7.34 Foam hull 2 1.72 7.61 Silicone gel pad 3 2.26 10.52 Foam hull 4 3.25 12.72 Foam hull 5 1.25 13,31 Foam hull 6 2.06 15.49 Inv gel-1 / 9g / 35 μm film 7 2.28 15.62 Inv gel-0 / 20g / film <35μm 8 3.37 17.17 Foam and air pad 9 4.27 17.62 Foam hull 10 2.25 18.17 Inv gel-1 / 9g / 35μm film 11 2.32 19,01 Inv gel-2 / 5g / 40μm film 12 4.09 20.48 Fiber hull 13 2.41 20.6 Inv gel-1 / 9g / 35μm film 14 2.2 21.75 Inv gel-1 / 7g / 35μm film 15 2.26 23.45 Inv gel-2 / 5g / 35μm film 16 2.48 26 Inv gel-2 / 5g / 40μm film 17 2.3 30.85 Inv gel-2 / 7g / 35μm film 18 6.11 31.74 Foam hull 19 2.79 39,12 Inv gel-2 / 5g / 40μm film 20 5.11 45.32 Foam and air pad 21 7.53 72.38 Foam hull 22 4.71 89.47 Inv gel-2 / 10g / 40μm film 23 3.64 102.29 Foam and air pad

Claims (9)

1. Bra cup structure comprising two layers of foam (2, 3) bonded together, sandwiching between them, in their lower part, a pouch (4) containing a malleable material, characterised in that the malleable material is a silicone gel filled with polymer microspheres and cross-linked, and in that the two layers (2, 3) of foam are made of viscoelastic foam.
2. Structure as claimed in claim 1, characterised in the malleable material is disposed in a pouch (4) formed by two polymer films (5, 6) sealed together, for example made of polyurethane.
3. Structure as claimed in claim 2, characterised in that the thickness of the films (5, 6) is less than 40 µm.
4. Structure as claimed in any one of claims 1 to 3, characterised in that the malleable material of the pouch (4) has a density of between 0.60 and 0.75 g/cm³.
5. Structure as claimed in any one of claims 1 to 4, characterised in that the layers of visco-elastic foam (2, 3) are bonded to a textile material (11, 12).
6. Structure as claimed in any one of claims 1 to 5, characterised in that the weight of silicone gel in the pouch (4) is substantially between 7 and 9 grams.
7. Structure as claimed in any one of claims 1 to 6, characterised in that the shape of the pouch (4) is substantially elliptical, with a major axis of between 8 and 15 cm and a minor axis of between 4.5 and 7 cm.
8. Structure as claimed in any one of claims 1 to 7, characterised in that the average thickness of the pouch (4) is between 2 and 3 mm.
9. Structure as claimed in any one of claims 1 to 8, characterised in that the normalised indentation force at 25% in the cup of the invention, in the part where the pouch (4) is located, is between about 2 and 3 N, and the normalised indentation force at 65% in the same location is between about 15 and 30 N.

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