RU2462217C2 - Method and device for manufacturing multilayer structure - Google Patents

Method and device for manufacturing multilayer structure Download PDF

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RU2462217C2
RU2462217C2 RU2010146930/12A RU2010146930A RU2462217C2 RU 2462217 C2 RU2462217 C2 RU 2462217C2 RU 2010146930/12 A RU2010146930/12 A RU 2010146930/12A RU 2010146930 A RU2010146930 A RU 2010146930A RU 2462217 C2 RU2462217 C2 RU 2462217C2
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layer
material
layers
welding
multilayer structure
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RU2010146930/12A
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RU2010146930A (en
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Мария ФЕРНКВИСТ (SE)
Мария ФЕРНКВИСТ
Марюам ТОНДКАР (SE)
Марюам ТОНДКАР
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Ска Хайджин Продактс Аб
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Abstract

FIELD: medicine.
SUBSTANCE: invention relates to method of manufacturing multilayer structure (22) for application in absorbing product, such as diaper, sanitary napkin, sanitary towel, absorbing diaper, used in case of incontinence, etc., formed by multiple layers (6, 7, 8) of material, containing, at least, first layer (6), which is liquid-permeable, second layer (7), forming absorbing element (7) and third layer (8), each of said layers (6, 7, 8) being made of material which has specified radius of pores (R1, R2, R3), claimed method contains stages, at which: said layers (6, 7, 8) of material are connected by means of, at least, two stages (4, 12) of ultrasonic sealing, and provide pattern (15, 17) of ultrasonic sealing for each of said stages of sealing, each of said patterns (15, 17) of sealing being formed by multiple places (16, 18) of connection. Method in accordance with invention contains stages, at which said stages (4, 11) of sealing are provided for formation in general integral absorbing product; and said patterns (15, 17) of sealing are selected in such a way that, at least, generally multilayer structure (22) has pores of multitude of radii. Said stages (4, 11) of sealing contain, at least, and in the following sequence: first stage of sealing, at which third layer (8) and second layer (7) are connected, and second stage of sealing, at which connected third and second layers (8, 7) are connected with first layer (6).
EFFECT: provision of method and device for manufacturing multilayer material for absorbing product, improved in comparison with product of the previous level of technology and having optimal characteristics of liquid absorption and relatively low degree of secondary damping.
12 cl, 8 dwg

Description

FIELD OF TECHNOLOGY

The invention relates to a method for manufacturing a multilayer structure for use in an absorbent article such as a diaper, sanitary napkin, panty liner, absorbent diaper used for incontinence, or the like, formed by a plurality of layers of material containing at least a first layer which is permeable for liquid, a second layer representing an absorbent element (absorbent core), and a third layer, each of these layers being made of a material having pores of a certain p radius, said method comprising the steps of: connecting said layers of material by means of at least two ultrasonic welding steps and provide an ultrasonic welding pattern for each of said welding steps, each of said welding patterns defined by a plurality of connection points.

The present invention also relates to a device for manufacturing a multilayer structure for use in an absorbent article such as a diaper, sanitary napkin, panty liner, absorbent diaper used for incontinence, or the like, formed by a plurality of layers of material containing at least the first layer being water-permeable, the second layer, which is an absorbent element, and the third layer, each of these layers being made of a material having pores of a certain radius, Said device comprises: at least two ultrasonic welding devices for connecting said layers of materials; each of these ultrasonic welding devices is configured to provide an ultrasonic welding pattern defined by a plurality of joints.

The present invention also relates to a multilayer structure for use in an absorbent article such as a diaper, sanitary napkin, panty liner, absorbent diaper used for incontinence, or the like, formed by a plurality of layers of material containing at least the first layer which is permeable , a second layer representing an absorbent element, and a third layer, each of these layers being made of a material having pores of a certain radius, said multilayer structure cheers formed by joining said layers of materials with at least two ultrasonic welding steps, providing an ultrasonic welding pattern for each of said welding steps, each of said welding patterns defined by a plurality of connection points.

BACKGROUND OF THE INVENTION

Current absorbent products, such as diapers, panty liners, absorbent diapers for incontinence, potty training panties and similar products, are usually made using methods and systems that combine different types of layers of materials and absorbent elements.

A traditional absorbent article is typically in the form of a layered product containing a liquid permeable top sheet (e.g., non-woven fabric based on synthetic or natural fibers) that faces the wearer's body, an absorbent structure (e.g., a layer of fibrous material serving as a spreading or spreading layer liquid, and an absorbent element) and a liquid impermeable lower layer, for example, in the form of a sheet of thermoplastic facing the user's clothing. These various layers can exist as single sheets of material or multilayer structures.

To date, it is known to manufacture various types of multilayer structures from layers of various materials, for example various fibrous layers, for use as an absorbent article of the aforementioned type. The manufacturing process of such products typically comprises various stages in which layers in a multilayer structure are joined to each other by various types of technological processes, for example, bonding, high temperature bonding or ultrasonic bonding.

The bonding process is based on applying adhesive to the material layer in accordance with a predetermined bonding pattern and then combining this material layer with the next material layer. In addition, in high-temperature bonding, two or more layers in a multilayer material are joined by heat-melting fibers in a layer having hot-melt fibers. For this, the layers are fed through a device having a gap formed by two rollers having a certain pattern to create a connection. Finally, the ultrasonic bonding process comprises feeding two or more layers of material between the ultrasonic horn and the next roll (usually the so-called roll with a pattern) so that they are connected to form a specific joint pattern. All of these aforementioned technologies are known to those skilled in the art and are used to make multilayer structures for absorbent articles.

With regard to currently available technologies, there is a continuing need to improve certain characteristics of absorbent products. For example, it is important that such a product has optimal fluid absorption characteristics so that a high degree of fluid collection is ensured. In addition, the product must be made with a low degree of secondary moisture and it should also be perceived as dry by the user. This means that in order to provide greater comfort to the user, the product must have improved fluid distribution characteristics.

With regard to the prior art, it can be noted that document WO 00/02727 discloses a system and method for manufacturing a multilayer material by ultrasonic welding of pieces of material on a moving web of material. The system shown in WO 00/02727 comprises a first ultrasonic welding device in which said pieces of material are fastened with a first ultrasonic horn, and a second ultrasonic welding device in which pieces of material are then attached to a material web with a second ultrasonic horn.

In addition, patent document EP 1216679 discloses a method of manufacturing a multilayer material from layers of fibrous materials by joining layers of material using ultrasonic welding. In particular, EP 1216679 describes a method comprising two steps, namely a first step in which two layers are connected by ultrasound to form a first connection pattern, followed by a second step in which two connected layers are connected by ultrasound to a third layer. The second joint pattern differs from the first pattern in that it has a different joint region.

EP 1216679 also discloses how the joint pattern affects the properties of the laminate regarding the stiffness and stability of the belt in diapers with a belt and protective incontinence products.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method and apparatus for manufacturing a multilayer material for an absorbent article, in particular to provide an absorbent article improved over prior art products and having optimum liquid absorption characteristics and a relatively low degree of secondary wetting, as well as perceived by the user when using how dry.

This problem is solved by a method similar to the aforementioned one, said method comprising providing said welding steps to form a generally integral absorbent article and selecting said welding patterns so that at least the integral multilayer structure has a different pore radius.

The objective of the invention is also solved by means of a device similar to the aforementioned, and the ultrasonic welding device is configured to provide the specified welding steps to form a complete absorbent product, while these welding patterns are selected so that at least an integral multilayer structure has a different pore radius.

The objective of the invention is also solved by means of the aforementioned multilayer structure, which is formed using the above welding steps, while forming a generally complete absorbent product; moreover, these welding patterns are selected so that at least a complete multilayer structure has a different pore radius. Through the invention, certain advantages are obtained. Firstly, it can be noted that by welding the layers in several stages it is possible to obtain a product having different patterns of connection between the layers. A product having such a structure can provide better fluid collection and diffusion properties due to different pore radii.

The invention also provides improved contact between materials as well as a smoother product structure, which means that improved comfort for the product user can be achieved.

Unlike the prior art, the invention provides a solution to the aforementioned problem due to the fact that it is based on the understanding that the aforementioned ultrasonic welding steps affect the properties of the absorbent product, such as liquid collection and liquid absorption.

According to an embodiment, the invention is preferably made in such a way that, in general, the complete product is made by joining layers of material in a manner comprising a first welding step in which a third layer and a second layer are joined, and a second welding step in which the third and second layers are joined specified first layer.

Furthermore, according to an embodiment, the invention is preferably made in such a way that the first layer is made of a material with a pore radius equal to or greater than the pore radius of the second layer and the third layer, and also so that the second layer is made of material with a pore radius equal to or more than the radius of the pores of the third layer. This contributes to the provision of an absorbent article having improved liquid absorption, secondary wetting and dryness compared to prior art products.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to a preferred embodiment and the accompanying drawings, in which:

figure 1 is a schematic view of a device for the manufacture of absorbent elements in accordance with the principles of the present invention;

figa is a schematic perspective view showing the first step of a connection according to the invention;

fig.2b is a schematic perspective view showing the second stage of the connection according to the invention;

figure 3 is a schematic drawing illustrating the principles of the radius of the pores of the absorbent element;

4 is a schematic drawing illustrating the principles of the gradient of the radius of the pores in a multilayer structure made in accordance with the principles of the present invention;

5 is a schematic drawing illustrating the principles of different pore radii in a multilayer structure;

6 is a schematic drawing that further explains the principles regarding the welding process of a multilayer structure according to the invention;

7 is a diagram illustrating the principles of the invention.

PREFERRED EMBODIMENT

The principles of the present invention will now be described with respect to an embodiment of the invention. More specifically, the invention is preferably used in relation to absorbent articles, for example in the form of a thin sanitary napkin. However, the invention is not limited only to such absorbent articles and can, in principle, also be used for the manufacture of diapers, female panty liners, absorbent diapers used for incontinence, panties for training in a potty and similar products.

The invention is intended for use in the manufacture of such absorbent articles. More specifically, the invention is generally used to join two or more layers of materials, usually fibrous layers, to form part of a finished absorbent article.

Figure 1 shows a device 1 for manufacturing such a multilayer material from multiple layers of material. The device comprises a first roller 2 and an ultrasonic welding device 3 having an ultrasonic horn 4. The horn 4 is located at a predetermined, relatively small distance from the drum 2, thereby forming a gap 5 through which layers of some material are fed. According to a preferred embodiment, the invention is adapted to connect the first layer 6, the second layer 7 and the third layer 8. In addition, according to an embodiment, the first layer 6 is a liquid permeable top sheet, the second layer 7 is an absorbent element, and the third layer 8 is liquid impervious bottom sheet. However, as will be explained below, the invention is not limited only to such a configuration, but may differ from it within the scope of the attached claims.

As shown in FIG. 1, the second material layer 7 is preferably guided along the second roller 9. According to an embodiment, the invention provides for the execution of a series of process steps. The first of these method steps is the step of connecting the third layer 8 and the second layer 7. After this step, the multilayer material formed by the third material layer 8 and the second material layer 7 is connected to the first layer 6.

According to previously known principles, the first roller 2 is made with a pattern (not shown) in the form of a specific surface structure on its outer surface. The purpose of this figure is to help connect the third material layer 8 and the second material layer 7 during operation of the ultrasonic horn 4. Properties, such as the design, dimensions and depth of this figure, are determined based on the design requirements and the appearance of the finished multilayer material . The pattern on the first roller 2 may preferably comprise recessed portions and protruding portions, the protruding portions being the connection points, that is, the junctions of the third layer 8 and the second layer 7. The depth of the pattern is preferably in the range of about 0.3-2 mm.

A method of using the ultrasonic welding device 3 as such is known in the art, and for this reason it will not be described in detail herein. However, it can be noted that ultrasonic welding devices in general can be used for welding, cutting, punching or other types of processing of materials. In relation to the present invention, it is assumed that the treatment under consideration is ultrasonic welding to join two or more layers of absorbent product material to improve the collection and distribution properties of the liquid in the absorbent product. The invention is made, in particular, for the use of ultrasonic welding to change or adjust the pore structure of the layers 6, 7, 8, forming part of the product. In particular, the invention is made for welding a generally complete absorbent article to alter pore structure.

The second and third layers of material 7, 8, shown in figure 1, are fed through the gap 5 for connection using a given pattern of connection provided on the first roller 2, as discussed above. The joint pattern is selected in accordance with the requirements regarding the appearance, that is, the design, the finished product, as well as according to the requirements regarding the strength of the connection between the two layers of material 7, 8, and other requirements for the finished product.

When the second and third layers of material 7, 8 are connected to form a multilayer material, they are supplied to the next, third roller 10 and the second ultrasonic welding device 11 having an ultrasonic horn 12. Like the first gap 5, a second gap 13 is formed between the third roller 9 and the second ultrasonic horn 11. The second and third layers of material 7, 8 are layered on the first layer of material 6, which is also fed through the second gap 13. For this, the first layer 6 of the material is preferably guided along the fourth roller 14. Layers of material and 6, 7, 8 are fed in a direction indicated by an arrow in Figure 1.

The joining operation in the second ultrasonic welding device 11 is performed with the following joining pattern, which may or may not be similar to the first joining pattern provided by the first ultrasonic welding device 3. The principles regarding the design and possible sizes described for the first ultrasonic welding device 3 also apply to the second ultrasonic welding device 11.

In order to give the finished absorbent article a desired structure and a certain strength, there are two of the aforementioned welding steps for joining three layers 6, 7, 8 of material. It should be noted that the strength of the product is ensured primarily due to the fact that the structure becomes more stable due to the welding process and, in addition, due to the fact that as a result of the welding process, a relatively three-dimensional structure is created that provides improved comfort. Other properties, such as the degree of absorption of the liquid, dryness and distribution of the liquid, are caused, at least in part, by the two welding steps described.

For the manufacture of an absorbent article, a combined multilayer material is preferably used comprising three layers 6, 7, 8 of material. By way of example only, it can be assumed that the first layer 6 is a liquid-permeable top sheet, preferably of a non-woven material, based on synthetic or natural fibers, which is closest to the wearer's body of the final product when it is used. According to such an example, the first layer 6 is preferably made of a non-woven material formed by synthetic fibers such as polyethylene, polypropylene, polyester, nylon or the like. Other fibers may also be used, such as, for example, binder fibers, copolymer fibers, split fibers, nanofibres, etc. In addition, mixtures of various types of fibers can be used for this purpose. Alternatively, the first layer 6 may be made of other materials, such as a thermoplastic film, or a polyester film, or a multilayer material, or a combination of various multilayer materials. It can also be perforated or non-perforated, in accordance with a given pattern.

As for the first material layer 6, it can be further noted that the invention is preferably made in such a way that the first material 6 is a material having the largest pores of all layers 6, 7, 8 of the multilayer material. The largest pores are relatively easily released from the liquid, which means that the liquid held within the porous structure of the first material layer 6 can relatively easily flow into the adjacent material layer, that is, into the second material layer 7. This characteristic is based on the notion that relatively large pores are easily freed from the contents. The aim of the invention is that in this way the pores of the first material are freed from the liquid almost instantly.

In other words, in order to ensure effective fluid removal, the first layer 6 of material is preferably selected so that its pores are larger than the pores of the remaining layers 7, 8. In addition, the limitations and pore sizes of the first layer 6 are primarily associated with the underlying layers 7, 8. These principles will be described in more detail below with respect to FIGS. 3-5.

In addition, the first layer 6 is preferably constructed with dimensions selected so that its maximum thickness has a preferred size of 5 mm and its maximum density is preferably about 100 g / m 2 , most preferably 50 g / m 2 . In addition, the first layer 6 may itself be made in the form of a multilayer material having various types of fiber structure. However, the total density should preferably not exceed 100 g / m 2 .

In addition, and also according to the embodiment shown in FIG. 1, the second layer 7 may be in the form of an absorbent structure, or a layer, or an absorbent element, preferably containing fibrous material, designed to obtain a suitable degree of collection, distribution and absorption of liquid. Therefore, the second layer 7 can be a porous, elastic, relatively thick layer of material, for example, in the form of a fibrous packing material or a similar type of material with a high ability to absorb liquid and a high degree of absorption of the liquid.

The second layer 7 may contain natural or synthetic fibers or a mixture of such fibers. In addition, the second layer 7 may contain a suitable amount of superabsorbent material. This design contributes to a very high level of absorption of the entire absorbent product. In addition, the second layer 7 may be a single layer of material or a multilayer material. In the latter case, the second layer 7 can be formed by a multilayer material with a layer of packing material and an absorbent element.

You can also mention that the second layer 7 may contain a suitable amount of thermoplastic fibers to ensure the process of ultrasonic welding properly.

In addition, in accordance with the principles of the invention, the second layer 7 is preferably made with a finer porous structure than in the first layer 6, that is, having a smaller pore radius than in the first layer 6. In addition, the pore radius of the second layer 7 should be larger the radius of the pores of the third layer 8, that is, the second layer 7 has a rougher fiber structure than the third layer 8 (and the following underlying layers).

Finally, according to an embodiment, the third layer 8 may be a lower layer, which is preferably liquid impermeable (or has at least very high resistance to liquid penetration), and therefore is provided to prevent leakage of liquid from the finished product. For this, the third layer 8 is preferably made of a liquid impermeable material, such as a thin and sealing plastic film. For example, plastic films made of polyethylene, polypropylene or polyester can be used for this purpose.

According to an alternative embodiment, the third material layer 8 may not be the aforementioned bottom sheet, but, for example, another absorbent layer.

In addition, FIG. 2a shows a simplified perspective view of a bonding process for a third material layer 8 and a second material layer 7 according to a preferred embodiment of the invention. The drawing shows the first connection pattern 15, resulting from the transmission of the second and third layers 7, 8 through the first ultrasonic welding device 4 and their connections. The first connection figure 15 is selected taking into account, for example, the appearance of the product, the strength of the finished product and the properties of fluid collection. Figure 15 connections may be different. For example, the connection pattern 15 may take the form of a square or rectangular pattern having a distance of 1-3 cm between the joints. Preferably, to ensure effective fluid collection, the distance between the junction of the junction of the junction 15 should not exceed about 3 cm.

Fig. 2a also shows a coordinate system according to which the material layers 8, 7 according to the invention are arranged. More specifically, the longitudinal direction along which the layers 8, 7 of the material are elongated is called the x-direction. The direction perpendicular to the x-direction is called the y-direction, and the direction perpendicular to the plane generally formed by the surface of each of the layers 8, 7 of the material is called the z-direction.

After the third and second layers 8, 7 have been connected, they are then attached to the first layer 6 in a similar manner, by means of a second ultrasonic horn 11. This is shown schematically in FIG. 2b. Thus, a second connection pattern 17 is formed, also containing a plurality of connection points 18. According to an embodiment, the first connection pattern 15 and the second connection pattern 17 are different from each other, but they can also have a similar shape.

The welding sequence of the layers 6, 7, 8 is sequentially illustrated in FIGS. 2a and 2b. An important characteristic of the invention is that welding is carried out in a certain sequence, that is, first a third material layer 8 (preferably a lower sheet) and a second material layer 7 (preferably an absorbent layer). When these two layers 7, 8 are connected, the first layer 6 (preferably the top sheet) is added preferably to the other layers also by bonding.

Therefore, in order to provide a multilayer material in accordance with the principles of the invention, it is preferable to start this process by welding the second and third layers 7, 8, that is, those layers which, when using an absorbent product, are located farthest from the body. The reason for this is that (that is, if you start from the top, first layer 6) there is a risk that the pores will be too small and as a result, the first layer 6 will be too dense and impermeable. This is contrary to the purpose of the invention. Therefore, it will be impossible to create a finer fiber structure (i.e., having smaller pores) when it is welded to the remaining layers. In this case, effective fluid collection will not be possible. The next important principle is that welding should preferably be performed between all layers 6, 7, 8 of the material forming the finished product, that is, including the second layer 7, which in this case is an absorbent layer.

To further explain the principles and features of the invention, several basic concepts will be described. First, the term “pore radius”, as mentioned above, will be described with reference to FIG. 3, which shows a section of an absorbent layer 19 with a mesh 20, or a matrix made of fibrous material. The fibrous network 20 forms many pores, each of which has a specific size and volume. As an example, in FIG. 3, a pore is schematically shown at 21. For this pore 21 (and for any pore in the grid 20), a measure of its “pore radius” can be determined. Due to the irregular shape of the fiber network 20, these pores are obviously not completely round. Instead, a measure of the "effective" pore radius R can be obtained from the Laplace equation. As such, this is known in the art, and for this reason it will not be described in detail here. We can only mention that the effective pore radius R is approximately determined by the following formula:

R = 2 γ L cosθ a, r / Δ p ,

where γ L is the surface tension of the liquid, θ a, r is the approaching or retreating angle of wetting of the liquid with respect to the structure, and Δ p is the pressure difference on the meniscus that defines the surface of the liquid facing the air.

The principles of the invention will now be described with reference to FIG. 4, which shows a multilayer structure 22 (also called a multilayer material) composed of three different fibrous layers corresponding to the three layers 6, 7, 8 of the material of the present invention. The drawing shows examples of three different pores 23, 24, 25, one in each layer 6, 7, 8. As mentioned above, the invention is made so that the first layer 6 is made of a material in which the corresponding pore 23 has a pore radius R1, which is equal to or greater than the radius of the pores R2 of the corresponding pores 24 of the second layer 7 and the radius of the pores R3 of the corresponding pores 25 of the third layer 8. In addition, the second layer 7 is a material having a radius of the pores R2, which is equal to or greater than the radius of the pores R3 of the third layer 8 This means that the laminate has a gradient Dimensions pores which varies in z direction (cf. Figures 2a with) due to decreasing of radius of pore sizes, counting from the first layer of material 6 to the third layer 8 of material.

As an example, we can mention that a multilayer material (not shown in the drawings) having layers of material, each of which forms pores with a radius of a certain size so that R1 <R2> R3, does not work as defined by the invention. In particular, such a solution does not provide the intended liquid collection effect, since the liquid will not efficiently flow from the upper layer to the middle layer.

According to an embodiment, the multilayer material is designed so that it has a pore size gradient in the direction through the finished multilayer material ("z direction"), that is, so that on the upper side of the finished product there is a relatively "wide" and "open" porous structure and so that the lower side of the product has a more "dense" and "closed" porous structure.

As an alternative to the embodiment described above, in which the first material layer 6 has pores with dimensions different from those of the second material layer 7 and the third material layer 8, it should be noted that the invention could also be practiced so that all layers 6 , 7, 8 materials included pores of generally the same size. The first case mentioned is based on the principle that according to the invention, using layers 6, 7, 8 having different pore sizes, a gradient of a plurality of pore sizes is obtained, but generally identical welding patterns are used in the two welding steps described above. On the other hand, the second case is based on the principle that a gradient of a plurality of pore sizes is obtained by using two different welding patterns, but the layers of material have generally the same pore sizes. In the framework of the present invention, it is possible to obtain both of these alternative solutions.

In addition, FIG. 5 is a schematic cross-sectional drawing of a laminate 22 ′ according to another embodiment of the invention. The multilayer material 22 'contains three layers 6', 7 ', 8' of material, each of which has a specific pore radius, and the pore radius of at least the first layer 6 'in x- and y-directions varies. This means that this first layer 6 'is made of a material having various fibrous structures along its longitudinal direction, i.e., the x-direction. In addition, each of these structures has a different pore radius. This is schematically shown in FIG. 5, where it is shown that the first layer 6 ′ has three different pores 26, 27, 28 with different pore radii.

As a result of the welding operation, the pores of the layers 6 ′, 7 ′, 8 ′ shown in FIG. 5 will be smaller and more densely located near the joints 16. In addition, it can be noted that the pore gradient in the x- and y-directions is obtained around such joints 16 as a result of welding.

Therefore, the invention is preferably made in such a way that the multilayer structure gives a pore gradient in both the z-direction and the x- and y-directions.

In practice, the ultrasonic welding process is based on the principle that the second and third layers 7, 8 are connected to each other using the first connection pattern 15 (cf. FIG. 2a), which contains a plurality of connection points 16 that are formed by compressing these layers 7, 8 of the material (when passing through the gap 5) and the supply of a suitable amount of energy using the ultrasonic horn 4. This causes softening and melting of the material of the layers 7, 8 in the positions determined by the places 16 of the connection, to connect the layers.

Figures 15, 17 of the compound used at each stage of the compound are selected to obtain the best fluid collection and distribution properties. According to the invention, the improved liquid collection and distribution properties of the finished product and the improved contact between the layers of material are obtained in particular by choosing the joint patterns 15, 17 so that the finished absorbent product has pores of a multitude of radii. There is also the advantage of a drier product surface as well as improved comfort.

This means that, according to the invention, the pore radius can be adjusted so that, for example, the connection points 16 of the first connection pattern 15 are selected with a first predetermined pore radius and that the connection points 18 of the second connection pattern 17 are selected with a second predetermined pore radius, which differs from the pore radius of the first joint figure 15.

The pore gradient of the absorbent product affects the flow of fluid, which will move into the underlying layers. According to an embodiment, the pore gradient is preferably controlled by arranging the pores in different layers so that they are more and more "densely spaced" for each subsequent layer or each subsequent step of the welding operation. The invention is based on the principle that all layers 6, 7, 8 of the material are connected by ultrasonic welding, and the connection patterns 15, 17 are chosen so that the pore size gradients are most optimal for each connection operation.

6 is a schematic sectional view, further showing the principles of welding of the multilayer structure 22 according to the invention. The drawing corresponds in general to figure 4, but shows, in particular, a method in which three layers 6, 7, 8 of the material have a specific welding pattern. More specifically, the second material layer 7 and the third material layer 8 are connected by means of a first welding pattern, designated in FIG. 6 as a plurality of connection points 16 ′. In addition, when the second and third layers 7, 8 are connected and form a multilayer material, the first material layer 6 is connected to this multilayer material by means of a second welding pattern, designated in FIG. 6 as many other joints 16 ".

The result of the welding operation shown in FIG. 6 is that the complete weld pattern will be a combination of joints 16 ′ connecting the second and third layers 7, 8, as well as other joints 16 ″ connecting all layers 6, 7, 8 This means that there will be more welding sections between the second and third layers 7, 8 than between the first and second layers 6, 7. Thus, the pore gradient in the multilayer structure 22 can be adjusted by means of a welding operation.

In the context of the present invention, optimization of the pore gradient means improving the collection, distribution of liquid and dryness of the finished product.

For example, the invention may be practiced by a method in which the material is more open to the back (lower) part of the product than to the surface part, to obtain a product in which a high degree of liquid diffusion is obtained, so that the liquid is quickly transported further from the surface of the product. It should be noted here that it is important to achieve close contact between the layers 6, 7, 8 of the materials. This is possible using the steps of ultrasonic welding, as explained above.

The invention also provides an improved and softer material structure due to the fact that the aforementioned welding steps create a rather “bulky” structure. This means that the top layer is made with "protrusions" or "ridges", which tend to create an increased space between the user's body and the surface of the top layer. Therefore, an air column or gap is created between the user and the product, which contributes to the efficiency of fluid flow. This also contributes to improved comfort, since the liquid is absorbed into the product faster and it is possible to prevent a film or coating of liquid from being created between the body of the user and the absorbent product.

The invention is based on the principle that the use of various joint patterns will provide a product having pores of multiple radii. 7 is a diagram showing two graphs that illustrate the purpose and function of the invention according to this principle.

The first graph 29, represented as a continuous line, shows how the distribution of pore volume in an ordinary multilayer structure, that is, a multilayer structure that is not welded by the method described in the invention, depending on the radius of the pore changes for an absorbent article. The second graph 30, shown by a dashed line, shows the corresponding situation, but with a multilayer structure that is welded or otherwise constructed, in accordance with the present invention.

According to the graphs, it can be noted that the multilayer material according to the invention has a lower pore volume distribution (for a given pore radius) than previously known material. This means that the material according to the invention has a higher degree of fluid collection than prior art products, which is an advantage because it gives the user an improved feeling of dryness.

In addition, the first graph 29 shows that the invention provides a pore volume distribution in a multilayer material that is generally independent of the pore radius. In contrast, the multilayer structure of the invention, as described by the second graph 30, has a pore volume distribution that is highly dependent on the radius of the pores. In particular, the second graph 30 has a “peak” corresponding to a pore radius of a predetermined value, meaning that such a pore radius corresponds to a relatively large amount of liquid collecting in the surface of the article. According to the invention, improved fluid collection in the product can be obtained by shifting the “peak” of the second graph 30 to the left, as seen in the drawing. More specifically, the invention was created to move this graph 30 to the left for each welding step performed. This fact can be explained by the fact that a higher pressure is created in the pores due to the decreasing pore radius R. This means that more fluid will be released from the structure. This “offset” of the second graph 30 to the left is illustrated schematically with the arrow in FIG. 7.

Furthermore, due to the fact that the first layer 6 closest to the user's body has a pore radius that is equal to or greater than the pore radius of the second layer 7 and third layer 8, and also that the second layer 7 has a pore radius that is equal to or greater the radius of the pores of the third layer 8, by means of the invention provides improved fluid collection.

The invention is not limited to the embodiment described above, and may be varied within the scope of the appended claims. For example, the invention is not limited to any particular type of absorbent article and can be used to make diapers, female panty liners, absorbent diapers used for incontinence, panties for training in a potty, and generally for any other type of absorbent article. In addition, the invention may be practiced using many types of materials and combinations of materials.

The basic idea of the invention has been described with respect to an embodiment with three different layers. However, the invention can alternatively be practiced with a different number of layers and a different number of ultrasonic welding steps, and also with types of layers different from those described above. For example, the invention may be practiced in a structure having two nonwoven layers and two absorbent elements. Alternatively, the invention may be practiced in a structure having a nonwoven layer, two absorbent elements, and a bottom sheet. In general, the invention has been implemented in a manner in which a plurality of layers form a multilayer structure and in which the welding patterns used are preferably selected so that, in general, the multilayer structure has pores of a plurality of radii.

In addition, ultrasonic welding of the various layers can be performed at the same stage or in a plurality of successive stages.

Claims (12)

1. A method of manufacturing a multilayer structure (22) for use in an absorbent product, such as a diaper, sanitary napkin, panty liner, absorbent diaper, used for incontinence, or the like, formed by many layers (6, 7, 8) of material containing at least the first layer (6), which is permeable to liquid, the second layer (7), which is an absorbent element (7), and the third layer (8), each of these layers (6, 7, 8) made of material having pores of a certain radius (R1, R2, R3), where indicated This method comprises the steps in which: join together these layers (6, 7, 8) of material using at least two stages (4, 12) of ultrasonic welding and provide a picture (15, 17) of ultrasonic welding for each of these welding steps, each of these welding patterns (15, 17) being formed by a plurality of connection points (16, 18), characterized in that it comprises the steps in which: the indicated welding steps (4, 11) are carried out to form a generally complete absorbent product , select the indicated patterns (15, 17) of welding so that, at least, in general, the multilayer structure (22) had pores of many radii, and the indicated welding steps (4, 11) contain at least the following sequence: the first welding step, on which the third layer (8) is joined together a second layer (7), and a second welding step, in which the connected third and second layers (8, 7) are connected to the first layer (6).
2. The method according to claim 1, characterized in that the said welding steps are performed using the first layer (6) made of a material having a pore radius that is equal to or greater than the pore radius of the second layer (7) and the third layer (8), and also using a second layer (7) made of a material having a pore radius that is equal to or greater than the pore radius of the third layer (8).
3. The method according to claim 1 or 2, characterized in that the third layer (8) is a liquid impervious bottom sheet.
4. Device (1) for manufacturing a multilayer structure (22) for use in an absorbent product, such as a diaper, sanitary napkin, panty liner, absorbent diaper used for incontinence, or the like, formed by many layers (6, 7, 8) material containing at least a first layer (6), which is permeable to liquid, a second layer (7), which is an absorbent element, and a third layer (8), each of these layers (6, 7, 8) is made from a material having pores of a certain radius (R1, R2, R3), where e said device comprises at least two ultrasonic welding devices (3, 4, 11, 12) for joining together said layers (6, 7, 8) of material, each of these devices (3, 4, 11, 12 ) ultrasonic welding is configured to provide patterns (15, 17) of ultrasonic welding formed by a plurality of joints (16, 18), characterized in that said ultrasonic welding devices (3, 4, 11, 12) are configured to provide the indicated steps ( 4, 11) welding for the formation of a complete absorbent product, and the decree These welding patterns (15, 17) are chosen in such a way that, at least as a whole, the multilayer structure (22) has pores of many radii.
5. A multilayer structure (22) for use in an absorbent article such as a diaper, sanitary napkin, panty liner, absorbent diaper used for incontinence, or the like, formed by a plurality of layers (6, 7, 8) of material containing at least at least, the first layer (6), which is permeable to liquid, the second layer (7), which is an absorbent element, and the third layer (8), each of these layers (6, 7, 8) is made of a material having pores of a certain radius (R1, R2, R3), and the specified multilayer st The structure (22) is made by joining together the indicated layers (6, 7, 8) of material using at least two stages (4, 12) of ultrasonic welding, providing an ultrasonic welding pattern (15, 17) for each of these stages of welding moreover, each of these welding patterns (15, 17) is formed by a plurality of joints (16, 18), characterized in that the multilayer structure (22) is made using the indicated welding steps (4, 11), while a generally absorbent joint is formed product, and the indicated drawings (15, 17) of welding are selected in this way so that at least the multilayer structure (22) has pores of many radii.
6. The multilayer structure (22) according to claim 5, characterized in that the third layer (8) is a liquid impermeable lower sheet.
7. A multilayer structure (22) according to claim 5 or 6, characterized in that it is formed using the indicated welding steps (4, 11), comprising at least the following sequence: the first welding step, which are joined together a third layer (8) and a second layer (7), and a second welding step, in which the connected third and second layers (8, 7) are connected to the first layer (6).
8. A multilayer structure (22) according to claim 5 or 6, characterized in that said welding steps are performed using the first layer (6) made of a material having a pore radius that is equal to or greater than the pore radius of the second layer (7) and the third layer (8), and also using the second layer (7) made of a material having a pore radius that is equal to or greater than the pore radius of the third layer (8).
9. A multilayer structure (22) according to claim 7, characterized in that said welding steps are performed using the first layer (6) made of a material having a pore radius that is equal to or greater than the pore radius of the second layer (7) and the third layer (8), and also using the second layer (7) made of a material having a pore radius that is equal to or greater than the pore radius of the third layer (8).
10. The multilayer structure according to claim 5, characterized in that it contains two nonwoven layers and two absorbent elements.
11. The multilayer structure according to claim 5, characterized in that it contains a non-woven layer, two absorbent elements and a bottom sheet.
12. An absorbent article containing a multilayer structure (22) according to any one of claims 5 to 9.
RU2010146930/12A 2008-04-18 2008-04-18 Method and device for manufacturing multilayer structure RU2462217C2 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2104037C1 (en) * 1991-07-19 1998-02-10 Джонсон энд Джонсон, Инк. Liquid-absorbing sheet, method for manufacturing elastic liquid-absorbing sheet, expendable layered liquid-absorbing articles, packing article and tampon manufactured using liquid-absorbing sheet, and method for producing structurized cellulose fibers
WO1999049825A1 (en) * 1998-03-27 1999-10-07 Sca Hygiene Products Ab Material laminate for use as an outer layer on absorbent products
RU2228161C2 (en) * 1998-08-06 2004-05-10 Ска Хайджин Продактс Аб Fibrous structure and absorbing product containing such fibrous structure
RU2255721C2 (en) * 2000-02-07 2005-07-10 3М Инновейтив Пропертиз Компани Fastener for diapers with perforated separation line

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2104037C1 (en) * 1991-07-19 1998-02-10 Джонсон энд Джонсон, Инк. Liquid-absorbing sheet, method for manufacturing elastic liquid-absorbing sheet, expendable layered liquid-absorbing articles, packing article and tampon manufactured using liquid-absorbing sheet, and method for producing structurized cellulose fibers
WO1999049825A1 (en) * 1998-03-27 1999-10-07 Sca Hygiene Products Ab Material laminate for use as an outer layer on absorbent products
RU2228161C2 (en) * 1998-08-06 2004-05-10 Ска Хайджин Продактс Аб Fibrous structure and absorbing product containing such fibrous structure
RU2255721C2 (en) * 2000-02-07 2005-07-10 3М Инновейтив Пропертиз Компани Fastener for diapers with perforated separation line

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