RU2812799C2 - Method of making article of underwear, in particular bra - Google Patents

Abstract

FIELD: underwear.

SUBSTANCE: method for manufacturing a bra is proposed, which includes the following steps: using the first fabric layer (11) designed to form the outer layer of an underwear item, the second fabric layer (13) intended to form an inner layer of an underwear item, and the third material (17) made of hot-melt polyurethane film and designed to provide permanent connecting elements between the first fabric layer (11) and the second fabric layer (13) in the finished item of underwear; spraying on the first fabric layer (11), on the side that should be facing the second fabric layer (13), reactive polyurethane hot-melt adhesive, designed with the possibility of only one-time reactivation; placing said hot-melt polyurethane film (17) on that side of the second fabric layer (13) that should face the first fabric layer (11); combining said first and second fabric layers (11, 13) so that the side of the first fabric layer covered with reactive polyurethane adhesive faces the second fabric layer, and parts (17) of the hot-melt polyurethane film located on the second fabric layer face the first tissue layer; joining two fabric layers (11, 13) by hot pressing, with the above parts of hot-melt polyurethane film (17) placed between said layers; reactivating the reactive polyurethane adhesive to temporarily transition it into a liquid phase and then initiating a chemical cross-linking process to finally cure said adhesive to ensure fixation of said elements; and thermoforming the undergarment to the desired shape.

EFFECT: new method.

10 cl, 6 dwg

Description

This invention relates to a method for manufacturing an item of underwear, in particular a bra.

An article of this type must obviously have substantially good elasticity characteristics in order to guarantee a high degree of comfort for the person wearing it, preventing discomfort or even skin irritation.

In order to obtain the required degree of elasticity, strips of elastic fabric are usually used, which, however, essentially cannot provide optimal results in terms of comfort and prevention, for example, of marks on the skin due to the pressure created by such elastic fabrics.

An alternative, particularly in the case of bras formed by two superimposed layers of fabric, would be the use of silicone elements acting both as an elastic element and as an element connecting the two layers of fabric.

However, silicone is often objected to because it can be hazardous to health. In addition, the use of silicone elements will create problems in the final stage of thermoforming the bra to give it the final appearance required from an aesthetic point of view, as well as from a wear resistance point of view. In fact, thermoforming is usually carried out at temperatures close to 200°C, which will mean there is a risk of melting the silicone material and subsequent damage to the product.

The main object of the present invention is to overcome the above-mentioned disadvantages by providing a method for producing an underwear item, in particular a bra, which does not require elastic fabrics to achieve the required durability characteristics.

Another object of the present invention is to provide a method for making a bra that does not contain silicone materials.

With this aim in mind, it was conceived, in accordance with the present invention, to carry out a method for manufacturing an article of undergarment, in particular a bra, comprising the following steps:

- the use of a first fabric layer intended to form the outer layer of the underwear and cut in accordance with a shape substantially corresponding to the projection of the stretched underwear on a plane;

- the use of a second fabric layer designed to form the inner layer of the underwear and cut in accordance with a shape substantially corresponding to the projection of the stretched underwear on a plane;

- the use of a third film material designed to provide permanent connecting elements between the first fabric layer and the second fabric layer in the finished undergarment, wherein said third film material is cut to form at least one central underbust portion, a pair of upper portions intended to be located in corresponding to the straps of the bra, and a pair of side parts designed to be located on the corresponding sides of the bra, wherein said third film material is a hot-melt polyurethane film containing no silicone;

- spraying on said first fabric layer, on that side of it which should be facing the second fabric layer, a reactive polyurethane hot-melt adhesive, designed to be reactivated only once by heating within a reactivation time period of at least 3 days from the moment application, preferably within 5 days from the date of application;

- placing the above parts of the hot-melt polyurethane film in the required position on that side of the second fabric layer, which should face the first fabric layer, for heat-sealing the said parts with the specified second fabric layer by hot pressing;

- combining said first and second fabric layers so that the side of the first fabric layer coated with reactive polyurethane adhesive faces the second fabric layer, and parts of the hot-melt polyurethane film located on the second fabric layer face the first fabric layer;

- connection of two fabric layers, cut according to appropriate shapes, by hot pressing within the specified period of reactivation of the reactive polyurethane hot-melt adhesive, while the above parts of the hot-melt polyurethane film are placed between the specified layers, reactivation of the reactive polyurethane adhesive for its temporary transition to the liquid phase, allowing penetration of said adhesive through the fibers of the fabrics being joined, and then initiating a chemical cross-linking process to finally cure said adhesive to ensure final and permanent fixation of said elements;

- thermoforming the underwear item in accordance with the required shape at the end of the chemical cross-linking process with polyurethane glue;

- placement of straps, hooks, tags and other possible accessories to finalize the item of underwear.

In order to understand the explanation of the novel principles of the present invention and its advantages over the prior art, one possible illustrative embodiment employing such principles is described below with the aid of the accompanying drawings.

On the drawings

fig. 1 is a plan view of the first shaped fabric layer before assembly,

fig. 2 is a plan view of the second shaped fabric layer before assembly,

fig. 3 is a plan view of the various elements used to join the two shaped fabric layers constituting the bra,

fig. 4 is a plan view of the second shaped fabric layer together with the above connecting elements applied before joining the first shaped fabric layer,

fig. 5 is a plan view of two shaped fabric layers aligned with each other, together with the above-mentioned connecting elements placed between them, covered with a protective paper sheet before thermal connection of the various components,

fig. 6 is a plan view of the undergarment with the two fabric layers joined, before the excess edges are cut off.

The bra according to the manufacturing method proposed in the invention is of the type containing two combined fabric layers, the outer layer having a distinctly aesthetic function, and the inner layer having a high degree of comfort and durability for the person wearing it.

The proposed method for manufacturing an item of underwear first of all involves the use of a first fabric layer 11, intended to form the outer layer of the bra, which is cut out in accordance with the shape 12, corresponding to the projection of the stretched item of underwear on the plane, but with slightly larger dimensions compared to the shape , which the product itself must have upon completion.

The wording “projection of a stretched object on a plane” in this document means the shape of a product (or part thereof) stretched on a plane. Essentially, this shape corresponds to the shape known in the field of clothing cutting and sewing as a "paper pattern", that is, the shape according to which the fabric must be cut to make a garment.

The proposed manufacturing method further provides for the use of a second fabric layer 13 designed to form the inner layer of the bra, which is cut out in accordance with the shape 14, essentially corresponding to the projection of the stretched underwear item on the plane.

Accordingly, the first fabric layer 11 will have slightly larger dimensions relative to the second fabric layer 13.

In accordance with the specific organizational requirements of the place of manufacture, the first and second fabric layers 11, 13 can be made in the form of continuous strips or in the form of underwear parts with final dimensions.

Fig. 1 and 2 schematically depict strips or parts of linen 15, 16, from which shapes 12, 14 are cut out, respectively.

The type of material for the first fabric layer 11 is essentially selected based on the aesthetic characteristics desired for the product. For example, such material can be selected from guipure, tulle, microfiber, silk, elastic cotton, etc.

The type of material for the second fabric layer 13 is instead essentially selected based on the comfort and durability characteristics desired for the product. For example, such material can be selected from microfiber, tulle, silk, stretch cotton, etc.

The proposed manufacturing method further provides for the use of a third film material 17 designed to provide permanent connecting elements between the first fabric layer 11 and the second fabric layer 13 in the finished underwear item.

As schematically illustrated in FIG. 3, the third film material 17 is cut into suitable shapes to respectively form at least one central underbust portion 18, a pair of top portions 19, 19' for positioning in correspondence with the bra straps, and a pair of side portions 20, 20', designed to align with the sides of the bra.

The film material 17 used to form said permanent connecting elements between the first fabric layer 11 and the second fabric layer 13 is a hot-melt polyurethane film material that does not contain silicone.

Preferably, two materials with different specific gravity are used for the specified thermo-adhesive polyurethane film, namely the so-called “heavy” first material for making the central underbust part 18 and the upper parts 19, 19' of the straps, and the so-called “light” second material for making the side parts sides 20, 20', having less thickness and weight per square meter than the previous part.

More specifically, a film having a thickness of 180 µm and a specific gravity of 210 g/m2 can be used as the "heavy" hot-melt polyurethane film, and a film having a thickness of 75 µm and a specific gravity of 90 g/m2 can be used as the light-weight hot-melt polyurethane film.

For example, with regard to these two types of hot-melt polyurethane material, films manufactured by FaitPlast, known respectively as Easy-Tech 1381 and Easy-Tech 897, have been found to be optimal for use.

According to the operating capabilities of the manufacturing plant, the first and second fabric layers 11, 13 and the hot-melt polyurethane film 17 may be fed, prepared, and cut simultaneously, or a specific predetermined sequence may be provided while remaining within the scope of protection of the novel principles of the present invention.

The proposed manufacturing method further includes spraying on the first fabric layer 11, on its inner side (i.e., the side that should face the second fabric layer 13), a reactive polyurethane (PUR) hot melt adhesive, designed to be reactivated only once using heating within a reactivation time period of at least 3 days from application, preferably within 5 days from application.

The adhesive is applied to the fabric while it is hot, at approximately 140°C, so that it is in liquid form. After about 30 s, this glue, distributed throughout the fabric, will turn into a solid state, which will persist until its next reactivation.

It has been found that for this purpose the use of a reactive polyurethane adhesive manufactured by the company Kleiberit and known as Kleiberit 900.7.9967 is particularly advantageous.

According to the operating capabilities of the manufacturing plant, the adhesive may be applied to the first fabric layer 11 before or after cutting the fabric into the mold 12.

The proposed manufacturing method further involves placing central underbust portions 18, upper strap portions 19, 19', and side portions 20, 20' made from a hot-melt polyurethane film 17 in the desired position on the inside of the second fabric layer 13 (i.e., side , which should face the first fabric layer 11), as shown in FIG. 4, and heat sealing said parts to the fabric layer 13 using hot pressing for about 15 to 20 seconds, preferably 16 seconds, at a temperature of about 160°C.

After the portions 18, 19, 19', 20, 20' are attached to the fabric layer 13, the protective backing of the hot-melt polyurethane film 17 is removed, as is well known to one skilled in the art, leaving only the elastic portion of the polyurethane film 17 attached to the fabric layer 13.

After carrying out the operations described so far, but within the period in which said reactive polyurethane hot melt adhesive is still capable of reactivation, it is possible to begin joining the two fabric layers 11, 13 (previously cut according to the corresponding shapes 12, 14) with the parts 18, 19, 19', 20, 20' hot-melt polyurethane film 17 placed between them until these parts are finally and permanently secured.

To carry out the step of joining two fabric layers 11, 13, it may be advantageous to position the first fabric layer 11, intended for making the outer layer of the bra, on a plane so that the side covered with reactive polyurethane adhesive is turned upward, place the second fabric layer 13, intended for making the inner layer of the bra, on the specified first layer, while parts of the hot-melt polyurethane film 17 are turned down, and ensure that the shape 14 of the second fabric layer 13 is within the shape 12 of the first fabric layer 11.

Thus, the parts 18, 19, 19', 20, 20' of the hot-melt polyurethane film 17 will be correctly placed between the two fabric layers 11, 13.

The assembly of the two fabric layers 11, 13, with the hot-melt polyurethane film pieces 17 sandwiched between them, is then advantageously covered with a paper sheet 21, as shown in FIG. 3, the purpose of which will be described below.

At this stage, hot pressing of two combined layers of fabric 11, 13 is performed. Due to the characteristics of the glue used described above, this operation can be performed within 5 days from the moment of applying the glue itself.

To perform this operation, the assembly of the combined layers of fabric 11, 13 together with parts of the hot-melt polyurethane film 17, covered with a layer of protective paper 21, is placed under the plane of a hot press, which exposes the material to about 120° C. for at least 10 seconds.

This heating reactivates the polyurethane (PUR) hot melt adhesive, which returns to a liquid state and penetrates the fibers of the fabrics to be joined. This reaction of the adhesive first provides the first step of mechanical grip and then initiates a chemical cross-linking process that causes the adhesive to finally cure so that the adhesive itself cannot be removed unless the two edges of the fabric are mechanically torn apart. Complete cross-linking of the type of adhesive used in the proposed manufacturing method takes approximately 7 days.

The purpose of the sheet of paper 21 is to prevent, during the heating stage in the press and subsequent liquefaction of the polyurethane hot-melt adhesive, from sticking to the press plane at the edges of the first fabric layer 11 extending beyond the mold 14 of the second fabric layer 13.

After hot pressing of the two aligned fabric layers 11, 13 is performed, the paper sheet 21 is removed and the underwear item appears as shown in FIG. 6, with a second fabric layer 13 that partially covers the first fabric layer 11, with portions 18, 19, 19', 20, 20' of hot-melt polyurethane film 17 placed between the two fabric layers 11, 13. Considering that, as was As shown, the first fabric layer 11 is initially shaped with dimensions slightly protruding beyond the second fabric layer 13, the undergarment will now temporarily have a peripherally projecting edge 22 formed by the first fabric layer 11.

After at least 7 days from hot pressing (i.e., the time required to ensure complete cross-linking of the polyurethane adhesive), the product is thermoformed to give the bra the desired shape and cup size. Such a process is well known to one skilled in the art and is therefore not described in detail herein.

At this stage, the raised edges 22 of the first fabric layer 11 are cut to the profile of the finished garment (also herein in accordance with techniques and methods known to one skilled in the art).

Finally, you can start placing adjustable straps, hooks, tags, etc. using normal sewing operations to finalize the garment.

At this point, it becomes clear how the method for producing an undergarment according to the present invention allows for a garment to be produced with superior performance despite not using elastic or silicone-based materials.

It will be appreciated that the above description of an embodiment employing the new principles of the present invention is presented as an illustrative example of such new principles and therefore should not be construed as limiting the scope of protection of the invention claimed herein.

For example, in addition to the portions 18, 19, 19', 20, 20' of the hot-melt polyurethane film 17 for joining the two layers of fabric 11, 13, other portions may be provided in appropriate locations depending on the particular aesthetic and/or functional characteristics as may be required or necessary from time to time.

In addition, the shape of the garment and the fabrics from which it is composed can also be selected based on the specific characteristics required.

Claims (19)

1. A method for manufacturing an item of underwear, in particular a bra, comprising the following steps: using a first fabric layer (11) designed to form the outer layer of the underwear and cut in accordance with a shape (12) substantially corresponding to the projection of the stretched underwear on a plane; using a second fabric layer (13) designed to form an inner layer of the underwear and cut in accordance with a shape (14) substantially corresponding to the projection of the stretched underwear on a plane; the use of a third film material (17) designed to provide permanent connecting elements between the first fabric layer (11) and the second fabric layer (13) in the finished undergarment, wherein the third film material (17) is cut to form at least one central sub-bust portion (18), a pair of top portions (19, 19') for positioning in correspondence with the bra straps, and a pair of side portions (20, 20') for positioning on corresponding sides of the bra, wherein the third film material ( 17) is a thermo-adhesive polyurethane film that does not contain silicone; spraying onto the first fabric layer (11), on the side that should be facing the second fabric layer (13), a reactive polyurethane hot melt adhesive, designed to be reactivated only once by heating within a reactivation time period of at least 3 days from the date of application, preferably within 5 days from the date of application; placing said portions (18, 19, 19', 20, 20') of the hot-melt polyurethane film in the required position on that side of the second fabric layer (13) that is to face the first fabric layer (11) to heat-seal said portions to said a second fabric layer (13) by hot pressing; combining said first and second fabric layers (11, 13) so that the side of the first fabric layer (11), coated with reactive polyurethane adhesive, faces the second fabric layer (13), and parts (18, 19, 19', 20, 20') hot-melt polyurethane film located on the second fabric layer (13) were facing the first fabric layer (11); joining two fabric layers (11, 13) cut into appropriate shapes (12, 14) by hot pressing within a specified reactivation period of reactive polyurethane hot melt adhesive, wherein said parts (18, 19, 19', 20, 20') hot-melt polyurethane film placed between said layers, reactivating the reactive polyurethane adhesive to temporarily transition it into the liquid phase, allowing said adhesive to penetrate the fibers of the fabrics being joined, and then initiating a chemical cross-linking process to finally cure the adhesive, ensuring final and permanent fixation of said elements; thermoforming the underwear item according to the required shape at the end of the chemical cross-linking process with polyurethane adhesive; placement of straps, hooks, tags and other possible accessories to complete the underwear item. 2. The method according to claim 1, in which to make the central underbust part (18) and the upper parts (19, 19') for the straps, a hot-melt polyurethane film (17) is used, which has a first, higher specific gravity, and to make the side parts ( 20, 20') use hot-melt polyurethane film (17), which has a second, lower specific gravity. 3. The method according to claim 2, in which the hot-melt polyurethane film in accordance with the first, higher specific gravity has a thickness of 180 microns and a specific gravity of 210 g/m ² , and the hot-melt polyurethane film in accordance with the specified lower specific gravity has a thickness of 75 microns and specific gravity 90 g/ ^m2 . 4. The method according to claim 1, in which the heat sealing of the above parts (18, 19, 19', 20, 20') of the hot-melt polyurethane film with the second fabric layer (13) is carried out by hot pressing for about 15-20 seconds, preferably 16 seconds, at a temperature of approximately 160°C. 5. The method according to claim 1, in which the application of reactive polyurethane hot melt adhesive to the first fabric layer (11) is carried out at a temperature of approximately 140°C. 6. The method according to claim 1, in which the connection of two fabric layers (11, 13), with the above parts (18, 19, 19', 20, 20') of hot-melt polyurethane film placed between them, is carried out by hot pressing at a temperature of approximately 120 °C for at least 10 seconds. 7. The method according to claim 1, wherein the second fabric layer (13) is cut out in accordance with a shape (14) having dimensions substantially corresponding to the shape that the underwear item should have when finished, while the first fabric layer (11 ) are cut according to the shape (12), which is slightly larger than the shape that the finished item of underwear should have. 8. The method according to claim 7, in which the combination of the first and second fabric layers (11,13) with the parts (18, 19, 19', 20, 20') of the hot-melt polyurethane film placed between them is carried out by placing the mold (14) of the second fabric layer (13) within the shape (12) of the first fabric layer (11), thereby forming peripherally projecting edges (22) of said first fabric layer (11). 9. The method according to claim 8, wherein after thermoforming the underwear item according to the desired shape, the above-mentioned peripherally projecting edges (22) are cut off along the profile of the finished underwear item. 10. The method according to claim 8, in which, before hot pressing, both fabric layers (11, 13) are cut out in appropriate shapes (12, 14), with the above parts (18, 19, 19', 20, 20') placed between them. hot-melt polyurethane film, is completely covered with a protective paper sheet (21) to prevent the polyurethane hot-melt adhesive from sticking to the press plane in accordance with the above-mentioned edges (22) protruding beyond the periphery of the first fabric layer (11) covered with glue during hot pressing and subsequent liquefaction of the said glue.

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