RU2575757C2 - Absorbent structural element for absorbent articles - Google Patents

Abstract

FIELD: personal use articles.

SUBSTANCE: absorbent structural element for a diaper comprises an absorbent layer immobilised on a support sheet, having an absorbent material comprising superabsorbent polymer particles, and having in the front region the first and second essentially longitudinal channels, each of which does not comprise the said superabsorbent polymer particles.

EFFECT: providing better fitting of the article and its greater effectiveness during the entire cycle of its use.

15 cl, 9 dwg

Description

Application area

The present invention relates to an absorbent component for absorbent articles, such as diapers, comprising an absorbent layer with an absorbent material containing superabsorbent polymer particles and having first and second substantially longitudinal channels in the front region, each of which does not contain said superabsorbent polymer particles . The proposed absorbent structural element provides improved fit of the product to the body and higher efficiency of the absorbent product as a whole.

State of the art

Disposable absorbent articles for receiving and retaining body excretions, such as urine and feces, are well known. Examples of such products include disposable diapers, training panties and adult urinary incontinence products. Disposable diapers typically comprise a liquid-permeable topsheet facing the wearer's body, a liquid-impervious backsheet facing the wearer's clothes, and an absorbent core located between the topsheet and the backsheet.

Since their introduction into the market, manufacturers have continued to develop disposable diapers to make them better fit, more comfortable to wear and more functional.

An important component of disposable absorbent articles is an absorbent core (absorbent structural component). The absorbent core (absorbent structural component) typically includes a superabsorbent polymer material, for example, a hydrogel-forming polymer material, also referred to as absorbent gelling material (AGM). The superabsorbent polymeric material absorbs large amounts of body fluids, such as urine, by an absorbent product during its use, and in addition, it blocks absorbed fluids, ensuring minimal re-wetting and, therefore, sufficiently dry skin condition.

A superabsorbent polymeric material is typically incorporated into the structure of the absorbent core by means of a pulp of cellulose fibers. However, in recent years significant efforts have been made to develop thinner absorbent elements, which nevertheless could absorb and store large quantities of fluid secretions of the body, in particular, urine. Designs are proposed in which the absorbent core contains small amounts or does not contain cellulosic fibers at all.

In some cases, to maintain the mechanical strength of the elements of the absorbent cores, small amounts of a thermoplastic adhesive material, for example, a fibrous thermoplastic adhesive material, can be added to stabilize the absorbent polymer material. For this purpose, absorbent structural elements have been developed that have the required permeability / porosity, a reduced tendency of the gel to self-lock and have sufficient mechanical strength when using or transporting the product.

However, it was found that some types of structural elements of absorbent cores with a reduced content of cellulose fibers, being very thin before absorbing fluid secretions of the body, can have increased stiffness, being partially or completely filled, especially in areas in which the main absorbent capacity of the absorbent article is concentrated, such as, for example, the front region and the crotch area of the diaper. The increased rigidity of these areas is undesirable, since it impairs the ability of the absorbent product to fit snugly against the body when worn. Therefore, there remains a need for absorbent products having increased flexibility throughout the entire wearing cycle of the product, in particular, characterized by a better fit to the body in a wet state (at the same level of absorbent and retention capacity).

The inventors have found that with certain channels that do not contain particles of a superabsorbent polymer or a superabsorbent polymer material in the front region of the absorbent core / absorbent structure, diapers of increased flexibility can be obtained with equal performance characteristics.

SUMMARY OF THE INVENTION

The present invention relates to an absorbent diaper constituent member (17) comprising a support sheet (16) and an absorbent layer (50) of absorbent material comprising at least superabsorbent polymeric material and, optionally, cellulosic material, wherein the absorbent layer (50) is supported and immobilized by said supporting sheet (16); wherein said absorbent layer (50) has a transverse direction and an average width W, a longitudinal direction and an average length L, as well as a height direction;

and said absorbent layer (50) has first and second longitudinally extending side portions located on different sides of the longitudinal axis; and said absorbent layer (50) has a front region, a rear region and a crotch region located between them, arranged in series in said longitudinal direction;

wherein said absorbent layer (50) has at least a first substantially longitudinally extended channel (26) and a second substantially longitudinally extended channel (26) substantially free of said superabsorbent polymeric material, made through and extended in height of said absorbent layer (50), wherein the first channel (26) is located only in the front region of said first side part, and said second channel (26) is located only in the front region of said second b of the casing part, and each of the channels (26) has an average width W ′ of at least 4% of the average width W of said absorbent layer (50), or, for example, W ′ is at least 7% of W, and / or up to 25% of W, and / or at least 5 mm and up to 25 mm; however, said channels (26) are preferably not extended to any of the longitudinal side edges and the transverse front edge of said absorbent layer (50).

Mentioned absorbent layer (50) may contain one or more additional channels (26 ′; 26 ″), essentially not containing superabsorbent polymer material and essentially extended in the longitudinal direction, with each of their additional channels (26 ′; 26 ″) has an average width W ″ of at least 4% W. Additional channels may be located at least in the crotch region of said absorbent layer (50).

The said channels (26; 26 ′) are semi-permanent or permanent, and are immobilized on said supporting sheet (16). Immobilization can be performed by laying (in waves) the aforementioned support sheet (16) in the aforementioned first and second channels (26), or in parts thereof, and as an additional possibility, in the aforementioned additional channels (26 ′; 26 ′ ′) or their parts, that is, said support sheet (16) can be waved into said channels (26) or parts thereof. In addition, or alternatively, the absorbent structure (17) may comprise one or more adhesive materials for immobilizing said absorbent material on said supporting sheet (16). For example, said one or more adhesive materials may include a first adhesive material (40) applied to said absorbent layer (50) immediately after applying the latter to said supporting sheet (16), and / or a second adhesive material (60) applied onto said supporting sheet (16) or a part thereof before applying said absorbent material (forming said absorbent layer (50)).

The present invention also relates to an absorbent core containing an absorbent structural element (17) in accordance with the present invention (hereinafter referred to as the first absorbent structural element (17)), and containing additional material located in close proximity to said absorbent layer (50), when this additional material is selected from i) an additional support sheet (16), i) a layer of the receiving material; iii) a second absorbent structural member comprising a second support sheet (16, 16 ′) and a second absorbent layer (50, 50 ′), said second absorbent layer (50, 50 ′) and said absorbent layer (50) of the first element layers between said supporting sheet (16) of the first element and said second supporting sheet (16), with the optional second absorbent structure being the same as in any of the embodiments mentioned above. The second absorbent structure may also be an absorbent structure (17) in accordance with the present invention, and said channels (26) of said second absorbent structure (17) may be substantially identical to said channels (26) of said first absorbent structure (17) ) and, in essence, completely overlap with them. The second absorbent structural element may be an absorbent structural element (15) without channels, but may, for example, comprise a backing sheet (16 ′) and an absorbent layer (50 ′) with absorbent material in accordance with the present invention, and as an additional feature, an adhesive in accordance with the present invention.

The support sheet (16) of the first absorbent structural member (17) and / or the second support sheet (16 ′) can be laid (in waves) in said channels (26) or parts thereof, and one or more support sheets (16; 16 ′) may contain one or more adhesive materials (deposited on one or more support sheets (16) and / or on said absorbent layer (50)), and wherein said support sheets (16; 16 ′) are glued to each other in said channels (26) said adhesive material (the same may apply to any additional itelnym channels (26 '; 26' '), if any), and / or may be attached to each other bonding method under pressure, or with the aid of said adhesive may be adhered to said absorbent layer in said channels.

In some embodiments, pressure can be applied selectively to portions of the material of the backing sheet (16) corresponding to said channels (26) (for example, by means of a pressure application such as a roller whose protruding parts correspond to said channels (26)), for additional laying (waves) of said supporting sheet (16) into said channels (26), and pressure may additionally be applied to said absorbent layer (50) and / or said supporting sheet (16) containing one or more dgezivnyh materials and additional pressure applying means - for laying and fastening said supporting sheet (16) in said channels (26).

In some embodiments, the front transverse edge region (G) preferably does not contain any channels and has an average longitudinal dimension of 5% to 15%, or up to 10%. If there are channels (26) in the rear region of the product, then in some embodiments it is possible that the zone (F) of the rear transverse edge also does not contain any channels, and this zone (F) has an average size in the longitudinal direction of 5% up to 15%, or up to 10%.

In some embodiments, as shown in FIG. 5, a receiving material (70) may be located on the absorbent core (7) or on the absorbent structural element (17), which can also be located in said channels, for example, on said supporting sheet (16) or an additional supporting sheet (16 ′ ), being laid by waves in the mentioned channels (26).

The absorbent layer (17) or the absorbent core in accordance with the present invention are characterized by an improved fit to the body even after absorption of fluid secretions of the body (e.g. urine). The present invention also relates to an absorbent article, such as a diaper, containing an absorbent structure (17) or an absorbent core (7) in accordance with the present invention.

Brief Description of the Drawings

FIG. 1. The view of the diaper in accordance with the present invention.

FIG. 2A. Axonometric view of an absorbent structural element in accordance with the present invention.

FIG. 2B. An axonometric view of an additional absorbent structural element that can be used in combination with an absorbent structural element in accordance with the present invention.

FIG. 2C. Axonometric view of an alternative embodiment of an absorbent structural element in accordance with the present invention.

FIG. 2D. Axonometric view of an alternative embodiment of an absorbent structural element in accordance with the present invention.

FIG. 3-5. Cross sections of alternative embodiments of an absorbent core in accordance with the present invention.

FIG. 6. Schematic illustration of a method of forming an absorbent core in accordance with the present invention, based on the connection with each other of two absorbent structural elements in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

The term "absorbent article" means devices that absorb and retain body excretion, and in particular, means devices that are worn on the wearer's body or placed in close proximity to the wearer's body to absorb and retain various body excretions. Absorbent products may include diapers for children and adults, including diapers, for example, training panties for children and underwear for adults with urinary incontinence, feminine hygiene products, for example, sanitary pads, panty liners, urological pads, panty liners mammary glands, sanitary napkins, baby bibs, wound dressings and the like. Absorbent products may include products for mopping, products for the food industry, and others. In the context of the present description, the term "fluid discharge" includes, but is not limited to, urine, blood, vaginal discharge, breast milk, sweat and feces.

In the context of the present description, the term "diapers" means devices located in close proximity to the skin of the user and designed to absorb and retain various secretions of the body. Diapers are worn by infants and incontinent persons in the lower part of the body, so that the diaper surrounds the wearer's waist and legs. Examples of diapers include conventional type diapers for infants and adults, and panty diapers, including training panties. In the context of the present description, the term "training panties" means a disposable underwear with an opening for the waist and openings for the legs, and intended for small children. Panty-shaped diapers may also be available for adult users. Such panty diapers can be worn on the user by threading the user's legs into the leg openings and then pulling them up to the desired position around the bottom of the user’s body. The diaper-panties are given the finished shape in the process of their production by any suitable means, including, but not limited to: fastening to each other parts of the product by various fastening methods, allowing for single and / or multiple fastening (for example, thermal bonding, welding, adhesive, cohesive bonding , fasteners and other types of fastening). The fastening of the parts of the diaper-panties can be performed in any part of the circumference of the waist opening (for example, on the sides, on the front waist part and in other areas).

In the context of the present description, the term “disposable” is used to describe products that are generally not intended to be washed, otherwise restored, or reused (that is, it is understood that such products should be discarded after initial use, and preferably recycled, composted or removed in another way that is friendly to the environment.

In the context of the present description, the term "absorbent structural element (17)" means a three-dimensional element that can be used to absorb and retain liquids, such as urine. The absorbent structure (17) may be the absorbent core of the absorbent article, or may only be part of the absorbent core of the absorbent article, for example, the absorbent component of the absorbent core, as will be described in more detail below.

In the context of the present description, the term "superabsorbent polymer material" means essentially a water-insoluble polymer material that can absorb 0.9% saline in demineralized water in an amount of at least 10 times (typically at least 15 times or at least 20 times) over its own weight when measuring the absorbing capacity by centrifugation (Edana 441.2-01).

In the context of the present description, the term "non-woven fabric" means a fabric made of directional or randomly oriented fibers, excluding paper and products that are woven, knitted, combed, stitched fibers or threads, or felted wet, with or without additional fleece . Non-woven materials and methods for their manufacture are well known in the art. In general, nonwoven fabrication processes include the steps of laying fibers on a forming surface, and may include methods such as spinning with styling, melt blowing, carding, aerodynamic styling, wet styling, co-molding, and combinations thereof. The fibers can be of natural or artificial origin, and can be staple fibers, continuous filaments or formed at the site of formation of the fabric.

Absorbent Feature (17)

The absorbent structure (17) in accordance with the present invention comprises a support sheet (16) with an absorbent layer (50) of absorbent material. The absorbent material contains at least a superabsorbent polymeric material and, as further possible, a cellulosic material, for example, cellulose, cellulose pulp or modified cellulose. The absorbent structural element (17) may contain additional components, for example, one or more adhesive materials (40; 40 ′; 60), which will be described in more detail below. The absorbent layer (50) is three-dimensional and contains the first essentially longitudinal channel (26) and the second essentially longitudinal channel (26), which essentially do not contain the mentioned superabsorbent polymer material. Other materials may be present in said channels (26), as will be described in more detail below.

The absorbent structural member (17) and the absorbent layer (50) have a longitudinal direction and an average length L, measured respectively in the longitudinal direction of the element, absorbent layer or absorbent article, and a transverse direction and an average width W, measured respectively in the transverse direction. The absorbent structural element (17) and the absorbent layer (50) have a front region located when the product is carried in front of the user, a rear area located when the product is worn in the back of the user, and a crotch area located between them. Each of these areas is extended over the entire width of the element / layer measured in the transverse direction, and each of them has a length of 1/3 of the average length of the element / layer.

The absorbent structural element (17) and the absorbent layer (50) have a central longitudinal axis and a central transverse axis perpendicular to said central longitudinal axis; said absorbent layer (50) and said absorbent structural element (17) have a pair of opposing longitudinal side edges (18) extended in the longitudinal direction of the element / layer, and a pair of opposing transverse edges (19), namely the front the transverse edge located in front of the user when wearing the product, and the rear transverse edge located in the back of the user when wearing the product. The longitudinal side edges (18) and / or the transverse edges (19) of the absorbent structure (17) or the absorbent layer (50) may be parallel to the central longitudinal axis and / or the central transverse axis, respectively, or one or more of them may be curved, for example, the element / layer may have a smaller size in the crotch region. As a rule, the longitudinal lateral edges are a mirror image of each other relative to the longitudinal axis X.

The central longitudinal axis X of the absorbent layer (50) defines the first and second longitudinal parts of the absorbent layer (50), respectively, collectively referred to as the longitudinal parts. Each of these longitudinal parts is present in said front region, crotch region, and posterior region, and accordingly, there is a front region of the first longitudinal part and a front region of the second longitudinal part, and so on. In some embodiments, said longitudinal portions of the absorbent layer (50) are mirror images of each other relative to the longitudinal axis of the layer.

The absorbent layer (50) contains at least a first channel (26) and a second channel (26), essentially not containing (for example, completely not containing) said particles of a superabsorbent polymer, while said channels (26) are through, extended through the thickness (height) of the absorbent layer (50). (At the same time, it is understood that a small, negligible amount of particles of superabsorbent polymer material may be incidentally present in the channels, which, however, does not affect their general functionality). If the absorbent layer (50) contains cellulose or cellulosic materials, then in some embodiments it may be preferable that said first and second channels (26) also do not contain cellulose / cellulosic material.

The first and second channels (26) are available only in the aforementioned front region of the absorbent layer (50) (and accordingly the absorbent structural element (17)). Typically, the first channel (26) of the absorbent layer (50) is located in the front region of said first longitudinal part, and the second channel (26) is located in the front region of said second longitudinal part. The channels (26) operate as fold lines of the absorbent structural element (17) and provide an extremely comfortable fit of the product to the body. This is shown, for example, in FIG. 2A and 6.

The first and second channels (26) are essentially extended in the longitudinal direction, which means that each of these channels (26) is more extended in the longitudinal direction than in the transverse direction, and, as a rule, at least twice as long extended in the longitudinal direction than in the transverse direction.

This, in particular, includes channels (26) that are completely longitudinally longitudinal and parallel to the longitudinal direction of said absorbent layer (50) (i.e., parallel to said longitudinal axis), and also includes channels (26) that can be curved , provided that the radius of their curvature, as a rule, is at least equal to W; and this includes channels (26) that are straight but angled (e.g., from 5 ° to 30 °, or to 20 °, or to 10 °).

The first and second channels (26) have an average width W, which is at least 4% of the average width W of said absorbent layer (50), or, for example, at least 7% W; and / or, for example, up to 25% W, or up to 15% W; and / or, for example, at least 5 mm; or for example, up to 25 mm, or, for example, up to 15 mm.

Each of the aforementioned first and second channels (26) has an average length L ′, which can be, for example, up to 30% of the average length L of the said absorbent layer (50); for example, up to 25% L, or up to 20% L, and / or L ′ may be at least 5% L, or at least 10% L; and / or, for example, up to 25% W, or up to 15% W and / or L ′ may be at least 10 mm, or at least 20 mm.

Channels (26), as a rule, are the so-called “permanent”. By “permanent” it is meant that the structural integrity of the channels (26) is at least partially preserved both in a dry and in a wet state, including during friction of the product against the user's body. To determine whether the channels are permanent, a test for the structural integrity of the channels in the wet state can be used, which allows you to determine how much the structure of the channels is preserved during swelling from a moist environment.

Test for structural integrity of the channels in the wet state

This test is intended to verify the structural integrity of the channel after it is saturated with a moist environment. The test can be carried out directly with an absorbent structure or with an absorbent core containing an absorbent structure. The test was carried out as follows.

1. Measured the length of the channel (in millimeters) in the dry state. If the channel is not straight, the length of the curve of the line passing through the middle of the channel was measured.

2. The absorbent structural element or absorbent core was immersed in 5 liters of synthetic urine substitute, which was a solution of sodium chloride in distilled water with a concentration of 9.00 g of NaCl per 1000 ml of solution. The temperature of the solution should be 20 ± 5 ° C.

3. After 1 minute after immersion in saline, the absorbent structure or absorbent core was removed from the solution and held vertically at one end for 5 seconds to drain the solution, and then straightened on a flat horizontal surface with the side facing the clothes down, if the side was recognizable. If the absorbent structure or absorbent core contains constricting elements, then the absorbent structure or absorbent core must be stretched tight in both directions: X and Y, so that no contraction is observed anywhere. After that, the edges of the absorbent structural element or absorbent core were fixed on a horizontal surface so as to prevent its possible contraction.

4. The absorbent structural element or absorbent core was coated with a rigid plate having a suitable weight and the following dimensions: the length was equal to the length of the absorbent structural element or absorbent core in the expanded state, and the width was equal to the maximum width of the absorbent structural element or absorbent core in the transverse direction.

5. A pressure of 18.0 kPa was applied to the portion of the test sample under the rigid plate for 30 s. Pressure is calculated based on the total area of said rigid plate. The pressure was created by installing additional weights in the geometric center of the rigid plate, that is, the total weight of the rigid plate and additional weights should provide a pressure of 18.0 kPa over the entire area of the rigid plate.

6. After 30 s, additional weights and a rigid plate were removed.

7. After that, the total length (in millimeters) of the channel sections that retained their structure was immediately measured. If the channel is not straight, the length of the curve of the line passing through the middle of the channel was measured. If none of the channel sections has retained its structure, then the channel is not permanent.

8. The structural integrity of the permanent channel in percent was calculated by dividing the total length of the channel sections that retained their integrity by the length of the channel in the dry state and multiplying by 100%.

According to the results of this test, the permanent channel in accordance with the present invention should maintain structural integrity by at least 20%, or 30%, or 40%, or 50%, or 60, or 70%, or 80% , or 90%.

Permanent channels (26) can, for example, be obtained by immobilizing an absorbent material on a support sheet (16), for example, by applying one or more adhesive materials (for example, the first material (40; 40 ′)), for example, on an absorbent material / on the absorbent layer (50) (on the surface opposite to the surface lying on the support sheet (16)), after said absorbent material is laid on said support sheet (16), for example, in the form of a fibrous adhesive; and / or, for example, by applying an adhesive material (for example, a second adhesive (60)) to said supporting material, prior to forming said absorbent layer (50), and / or by laying waves of a supporting sheet (16) into said channels (26) or parts thereof, as will be described in more detail below.

The absorbent cores (7) in accordance with the present invention may, in particular, comprise permanent channels formed by bonding the first supporting sheet (16) and the second supporting sheet in the channels. Glue can be used to bond both supporting sheets in the channels, but they can also be bonded using other known methods, for example, ultrasonic or thermal bonding. The support layers may be bonded to each other in a continuous or discontinuous manner along the length of the channels.

Thus, between the supporting sheet (16) and said absorbent layer (50) there may be adhesive material (for example, a second adhesive (60)). In addition, or alternatively, the absorbent component (17) may comprise an adhesive (40, 40 ′) applied to said absorbent material / absorbent layer (50), for example, after said absorbent material has been applied to said supporting sheet (16). This is shown, for example, in FIG. 3-5.

In any of these cases, the absorbent material is immobilized on the support sheet (16), and the parts of the support sheet (16) laid (in waves) are fixed in the said channels (26) or their parts, which ensures at least partial preservation of the channel structure (26) while using the product. So, for example, the adhesive material can (60) be applied to the backing sheet (16) uniformly or in the form of a specific structure, for example, by spraying or crevice coating, or by other methods known in the art. So, for example, the adhesive material can (60) can be applied to those parts of the backing sheet (16) that must accept the absorbent material, which allows the absorbent material to be immobilized on the backing sheet. Alternatively, the adhesive material can (60) be applied only to those parts of the backing sheet (16) that will be in close proximity to the said channels (26), or will be laid by the waves inside the said channels (26), resulting in a support sheet (16) inside said channels (26) will be glued to said absorbent material or to additional material, as will be described below. This is shown, for example, in FIG. 4 and 5.

The first and second channels (26) can be mirror images of each other relative to the central longitudinal axis X of the absorbent layer (50) / absorbent structural element (17).

In some embodiments, there is no channel (26) that matches the central longitudinal axis of said absorbent layer (50). Channels (26) can be spatially spaced from each other along their entire length. The smallest distance D between them can be, for example, at least 5% of the average layer size in the transverse direction, or at least 10%, or at least 15%; or at least 5 mm, or at least 8 mm.

In addition, to reduce possible leakage of fluids, the longitudinal channels (26), as a rule, are not extended to any of the transverse and / or longitudinal edges of the absorbent layer (50). Thus, for example, the smallest distance between the channel (26) and the closest longitudinal edge of the absorbent layer (50) is at least 5% of the average size W of the layer in the transverse direction, or preferably at least 10%. In some embodiments, the distance is at least 10 mm. Thus, for example, the smallest distance between the channel (26) and the nearest transverse edge of the absorbent layer (50) may, for example, be at least 5% of the average length L of the layer, preferably at least 10%. In some embodiments, the distance is at least 10 mm.

In addition to the first and second channels (26) described above, located only in the front region, the absorbent layer (50) (and accordingly the absorbent structural element (17)) may contain additional channels (26 ′; 26 ″), which are extended essentially in the longitudinal direction and in essence do not contain superabsorbent polymer material. The above description of the first and second channels (26) may equally apply to any of the aforementioned additional channels (26 ′; 26 ″). However, in some embodiments, the additional channels (26 ′; 26 ″) are longer than the first and second channels, for example, their length can be from 40% to 90%, or up to 80%, or up to 60% L.

So, for example, the front region of the absorbent layer (50) may contain one or more additional channels (26 ′; 26 ″), in addition to the first and second channels (26), and / or the central (crotch region) may contain one or more such additional channels (26 ′; 26 ″), which in some embodiments may be extended to said front and / or back regions; and / or the back region may contain one or more of such additional channels (26 ′; 26 ′ ′).

In some embodiments, the absorbent structure (17) comprises at least one additional channel (26 ′) in at least a central (crotch) region, which may be extended to said front and / or rear regions; or, for example, there can be two such additional channels (26 ′) located on different sides of the longitudinal axis, and they can be, for example, a mirror image of each other relative to the said longitudinal axis of the absorbent layer (50). The inventors have found that such additional channels (26 ′) provide quick fluid intake, which reduces the risk of leaks. Channels (26; 26 ′), especially if they are immobilized / permanent channels, help to avoid saturation of the absorbent layer in the area adjacent to the places where fluids are released from the body (saturation increases the risk of leaks). Such examples are shown in FIG. 2C and 2D.

Moreover, which is rather unexpected, the inventors found that although the total amount of superabsorbent polymer material in the absorbent structural element (17) is reduced (due to the presence of channels (26) not containing such material), the properties of the absorbent structural element (17), or of the whole diaper, in relation to interaction with fluids are improved.

In some embodiments, the front region comprises said first and second channels (26) and two additional channels (26 ′; 26 ″) located on different sides of the longitudinal axis; however, one additional channel (26 ′) is parallel to the first channel (26), and the second additional channel (26 ″) is parallel to the second channel.

In order to avoid the transfer of fluid to the transverse edges (19), the absorbent structural element (17) and the absorbent layer, as a rule, do not contain channels (26), extended completely or essentially in the transverse direction.

In some embodiments, the smallest lateral distance D between the two channels (26) is at least 5% W, preferably at least 10% W.

The first and second channels (26), and possibly also additional channels (26 ′; 26 ′ ′), can be located in said absorbent layer (50) so that there will be a central longitudinal strip having a certain minimum width (D; D ′), located symmetrically on the said longitudinal axis of the product and not containing any channels (26); wherein said absorbent material is preferably located in said strip in a substantially continuous manner. Thus, for example, said strip may have a minimum width (D; D ′) of at least 5% of W, or at least 10% of W. and / or at least 5 mm, or at least 10 mm , or at least 15 mm, and / or even up to 40 mm. In some embodiments, in the immediate vicinity of each of the first and second channels, and also, as an added opportunity, in the immediate vicinity of said one or more additional channels (26 ′; 26 ″), said absorbent material is substantially continuously arranged.

In some embodiments, it is preferable that the region (G) of the front transverse edge preferably does not contain any channels, and that the region (G) has an average size in the longitudinal direction of 5% to 15%, or up to 10%. If there are channels (26) in the rear region of the product, then in some embodiments it may also be preferable that the zone (F) of the rear transverse edge also does not contain any channels, and that this zone (F) has an average size in the longitudinal direction of 5% to 15%, or up to 10%.

In some embodiments, in the said central longitudinal strip between said first and second channels (26), the average specific gravity of the absorbent material, or said superabsorbent polymer material, may be from 350 to 1000 g / m ² , or, for example, from 450 g / m ² up to 750 g / m ² .

The absorbent structural element (17) typically contains additional material (for example, a layer of additional material) designed to cover the absorbent layer (50), and hereinafter referred to as "additional material". Such a design may be referred to herein as an absorbent core (7). Examples thereof are shown in FIG. 3-6.

The additional material may contain additional adhesive material (40 ′) on its surface, which should be placed in close proximity to the absorbent layer (50) of the absorbent structural element (17).

This additional material may be an additional absorbent structural element (17) containing a second layer of absorbent material and a second supporting layer (16), as a result of which both absorbent layers (50, 50 ′) will be located between the said supporting sheets (16); it may be an additional absorbent structural element (17) in accordance with the present invention with two or more channels (26 ′) described above. The channels (26) of the first absorbent structural element (17) and the second absorbent structural element (17) coincide and overlap with each other, for example, completely, or coincide only partially, or overlap only partially; or they may not even coincide or overlap with each other. In some embodiments, the channels are practically identical to each other, and the channels (26) of one absorbent structural element are essentially identical and overlap with the channels (26) of the second absorbent structural element. An example of such a construction is shown in FIG. 6.

In some embodiments, the additional material is part of a backing sheet (16) wrapped around the absorbent layer (50) and then secured at the peripheral edges so that they completely cover the absorbent layer (50).

In some embodiments, the absorbent structure (17) is coated with an additional support sheet (16) or an additional absorbent structure without channels, as shown in FIG. 3-5.

In some embodiments, the additional material may be a layer (70) of the receiving material and / or the receiving sheet, which may, for example, be attached to said supporting sheet (16). In some embodiments, as shown in FIG. 5, the receiving material (70) may be provided on said absorbent core (7) or on said absorbent structure (17), and may also be present in channels, for example, on said supporting sheet (16) or additional supporting sheet (16 ′) which are laid (in waves) in said channels (26).

In any of these cases, the stacked support sheet (16) or the above two support sheets (16) can be attached to each other at the peripheral edges, as a result of which they will completely cover one or more absorbent layers (50).

In any of these embodiments, the backing sheet (16) or the receiving layer / sheet can be laid (in waves) in said channels (26) or part thereof. The additional material may be glued to the support sheet (16) of the absorbent structural element (17) in accordance with the present invention in said channels (26), for example, with adhesive material, as described above.

In some embodiments, the absorbent structure (17) comprises such additional material covering said absorbent layer (50), and pressure is selectively applied to said supporting sheet (16) and / or said additional material, namely, those parts that get onto said channels (26) in order to feed these parts of said supporting sheet (16) and / or said additional material into said channels (26) to form said waves and / or for better bonding I with each other of said additional material and said supporting sheet (16) in said channels (26) if the adhesive material described above is used.

The means for applying pressure can be a pressure roller containing embossed protruding parts, essentially having a size, shape, pattern of said channels (26), and coinciding (mating) with said parts of a supporting sheet (16) or additional material matching with said channels (26 )

In some embodiments, the second support sheet (16) may be wider than the absorbent layer (50) / structural element, which allows you to lay the second support sheet (16 ′) in the channels (26) or part thereof, and thereby adhere it to the first support sheet (16).

In embodiments in which the absorbent core (7) comprises two or more absorbent structures (17) containing channels (26) in accordance with the present invention, it may be one, two, or more, or all of the channels (26) one absorbent structural element (17) is essentially superimposed on the channels (26) of an adjacent absorbent structural element (17). In this case, the absorbent core (7) is a laminate of absorbent structural elements with channels (26), while the channels (26) are through, essentially extended through the thickness of the absorbent layers (50).

In addition, or alternatively, embodiments are possible in which one, two, or more, or all of the channels (26) of one absorbent structure (17) are not superimposed on the channels (26) of an adjacent absorbent structure ( 17); they can be, for example, mated with respect to the channels of an adjacent absorbent structural element. By conjugate is meant that the channels (26) of the second absorbent structural element (17) form a continuation of the channels of the first absorbent structural element (17).

In some embodiments, the absorbent core (7) may contain two or more absorbent structural elements, one of which is an element (17) in accordance with the present invention, and another is an absorbent structural element (15) with a supporting sheet (16 ′), which is coated with an absorbent layer (50) (with a superabsorbent polymer material) without channels (26), as shown, for example, in FIG. 2B, 3-5.

Such a second absorbent structural element (15) may contain any supporting sheets, absorbent material and adhesive materials in accordance with the present invention.

Absorbent material

The absorbent layer contains an absorbent material, which in turn contains a superabsorbent polymeric material (for example, in the form of particles), possibly in combination with a cellulosic material (including, for example, cellulose or crushed wood pulp in the form of fibers). If the additional material described above contains absorbent material, then the following may also apply.

In one embodiment, the absorbent material may contain at least 60%, or at least 70% of a superabsorbent polymer material (by weight), and a maximum of 40%, or even a maximum of 30%, of the cellulosic material.

In some embodiments, the absorbent layer (50) comprises an absorbent material consisting essentially of absorbent polymeric materials, for example, in the form of particles, for example, less than 5% cellulosic material by weight (based on the weight of the absorbent material) may be present; and said absorbent layer (50) / absorbent structure (17) may not contain cellulosic materials.

Typically, a superabsorbent polymer material is present in particulate form. Suitable for use in the composition of the absorbent layer (50) are any particles of superabsorbent polymeric materials described in the relevant literature, for example, in the publication Mudern Siiperabsorbenl Polymer Technology (F.L. Buchholz, A.T. Graham, Wiley 1998). Particles of absorbent polymers can be spherical, close to spherical, irregularly shaped particles, wiener-shaped particles or ellipsoid-shaped particles, usually obtained in polymerisation reactions in phase reversal suspensions. Particles can also be partially agglomerated into larger particles of irregular shape.

In some embodiments, the absorbent material as a whole, and / or at least the particulate superabsorbent polymer material, has a high absorption capacity, for example, has a holding capacity (measured by centrifugation) of at least 20 g / g, or at least 30 g / g The upper limit may be, for example, 150 g / g, or 100 g / g.

In some embodiments, an absorbent material may be used comprising (or consisting of) superabsorbent polymer particles formed from acrylic acid polymers (polyacrylate polymers), for example, having a degree of neutralization of from 60% to 90%, or about 75%, for example, containing counterions sodium.

As superabsorbent polymers, polyacrylates and polyacrylic acid polymers having internal and / or surface cross-linking can be used. Suitable materials are described in patent publications WO 07/047598, WO 07/046052, WO 2009/155265 and WO 2009/155264. In some embodiments, superabsorbent polymer particles can be obtained using processes currently used in this field, in particular, using the process described in detail in WO 2006/083584. Superabsorbent polymers should preferably contain internal cross-bonds, that is, their polymerization should be carried out in the presence of compounds having two or more polymerizable groups that allow free radical copolymerization into the polymer chain. Suitable crosslinking compounds include ethylene glycol dimethacrylate, diethylene glycol diacrylate, allyl methacrylate, trimethylolpropane triacrylate, triallylamine, tetraallyloxyethane as described in EP-A 530,438, di- and triacrylates, as described in EP-A-5,47947, EP-A 632068, WO 93/21237, WO 03/104299, WO 03/104300, WO 03/104301 and in DE-A 10331450, mixed acrylates. which along with acrylate groups include ethylene-saturated groups, as described in DE-A 10331456 and DE-A 10355401, or mixtures of substances for crosslinking, as described in DE-A 19543368, DE-A 19646484, WO 90/15830 and WO 02/32962, as well as crosslinking agents described in WO 2009/155265. Superabsorbent polymer particles can have cross-bonds made on the surface (the so-called post-cross-bonds). Suitable compounds for forming such bonds include compounds having two or more groups capable of forming covalent bonds with the carboxylate groups of the polymers. Suitable compounds of this type include, for example, alkoxysilyl compounds, polyaziridines, polyamines, polyamidoamines, di- or polyglycidyl compounds as described in EP-A 083022, EP-A 543303 and EP-A 937736, polyols, as described in DE-C 3314019, cyclic carbonates, as described in DE-A 4020780, 2-oxazolidone and its derivatives, such as N- (2-hydroxyethyl) -2-oxazolidone, as described in DE-A 19807502, bis- and poly-2- oxazolidones, as described in DE-A 19807992, 2-oxotetrahydro-1,3-oxazine and its derivatives, as described in DE-A 19854573, N-acyl-2-oxazolidones, as described in DE-A 19854574 cyclic ureas as described in DE-A 10204937; bicyclic amide acetals as described in DE-A 10334584; oxetane and cyclic ureas as described in EP-A 1199327; and morpholine-2,3-dione and its derivatives as described in WO 03/031482.

Superabsorbent polymers or their particles can be surface modified, for example, they can be applied fully or partially. Examples of absorbent coated polymer particles are described in WO 2009/155265. The coating material can make absorbent polymer particles more hydrophilic. For example, such a substance may be hydrophilic (e.g. pyrogenic) silica, such as Aerosils. The coating material may be a polymer, for example, an elastic polymer, a film-forming polymer, or simultaneously an elastic and film-forming polymer, forming an elastic (elastomeric) coating on the particles in the form of a film. The coating may be a homogeneous and / or uniform coating on the surface of the absorbent polymer particles. The coating agent may be applied in an amount of from 0.1% to 5%.

Superabsorbent polymer particles may have a size in the range of 45 μm to 4000 μm, more preferably in the range of 45 μm to about 2000 μm, or from about 100 μm to about 1000, or up to 850 μm. Particle size distribution of the material in the form of particles can be carried out by methods known in the art, for example, by dry sieving (EDANA 420.02).

In some embodiments of the present invention, a superabsorbent material in the form of particles with a weight average particle size of up to 2 mm, or from 50 μm to 2 mm, or up to 1 mm, or preferably from 100, 200, 300, 400 or 500 μm, to 1000, 800 or 700 microns; measured by the method described, for example, in EP-A-0691133. In some embodiments of the present invention, a particulate superabsorbent polymeric material is used, with at least 80% of the particles by weight having a size of between 50 μm and 1200 μm, and the mass-median particle size is in any of the ranges indicated above. In addition, in one embodiment of the invention, said particles are essentially spherical. In yet another embodiment of the present invention, the superabsorbent polymer material has a relatively narrow particle size distribution range, for example, most (e.g. at least 80%, preferably at least 90% or even at least 95% by weight) particles are from 50 μm to 1000 μm, preferably from 100 μm to 800 μm, and more preferably from 200 μm to 600 μm.

Support sheet

The absorbent structural element (17) in accordance with the present invention contains a support sheet (16) supporting and immobilizing absorbent material (50). If there is additional material in the absorbent core and it is a support sheet (16 ′), or includes such a sheet, then the following also applies to it.

Such a support sheet may be made of a sheet or web that is divided into separate absorbent structural elements. Examples of starting webs include paper, films, woven or non-woven materials, or laminates from any of the listed materials.

In some embodiments, the backing sheet is a nonwoven fabric, for example, a nonwoven fabric, for example, a carded nonwoven fabric, a spunbond nonwoven fabric, or a meltblown nonwoven fabric, or a laminate of any of the aforementioned nonwoven fabrics.

The fibers may be of natural or artificial origin, and may be staple fibers, continuous fibers, or fibers that are formed in place. Commercially available fibers have a diameter in a wide range, from less than about 0.001 mm to more than about 0.2 mm, and come in various forms: short fibers (called staple or cut), continuous single fibers (filaments or monofilaments) non-twisted bundles of continuous fibers (tow) and twisted bundles of continuous fibers (yarn). The fibers can be two-component fibers, for example, shell-core configurations, in which the shell and core are formed from various polymers. Nonwoven webs can be made using various processes, such as melt blowing, spunbond, spinning from a solution, electrospinning and carding. The proportion of non-woven fabrics is usually expressed in grams per square meter (g / m ² ).

In the context of the present description, the nonwoven material may be made of hydrophilic fibers. Hydrophilic fibers are called fibers or surfaces of fibers that are wetted by water-based fluids (e.g., body fluids having a water base) deposited on such fibers. Hydrophilicity and wettability are determined, as a rule, by the angle of contact and the time of passage of the fluid through the non-woven fabric. These concepts are discussed in detail in the publication of the American Chemical Society "Contact angle, wettability and adhesion" edited by RobertF. Gould (1964). A fiber or fiber surface is considered to be wettable by the fluid (i.e. hydrophilic) if the contact angle between the fluid and the fiber, or its surface, is less than 90 °, or if the fluid tends to spontaneously spread across the fiber surface (usually both phenomena take place simultaneously). Conversely, a fiber or fiber surface is considered hydrophobic if the contact angle exceeds 90 °, and the fluid does not spontaneously propagate over the fiber surface.

The support sheet (16) in accordance with the present invention may be breathable. The materials from which it can be made may contain micropores. For example, breathable nonwoven webs may be used. The support sheet (16) may, for example, have a breathability of 40 or 50, up to 300 or 200 m ³ / (m ² × min), determined according to the EDANA method 140-1-99 (differential pressure 125 Pa, sample area 38.3 cm ² ). Alternatively, the backing sheet (16) may have lower breathability or be completely airtight, which, for example, allows it to be better held on a moving surface by vacuum.

In preferred embodiments, the backing sheet (16) is a non-woven laminate, for example a non-woven laminate, for example, an SMS or SMMS web.

To facilitate the formation of the waves described above, the support sheet (16) may have a specific gravity of less than 60 g / m ² , less than 50 g / m ² , for example, from 5 g / m ² to 40 g / m ² , or up to 30 g / m ² .

The support sheet (16) may be extensible in the CD direction or in the MD direction.

In one embodiment of the present invention, the support sheet (16) has waves laid in the aforementioned first and second channels, and possibly in the aforementioned additional channels (26 ′; 26 ″), or in parts thereof. So, for example, waves can be extended along the entire length of the channel in the longitudinal direction, can be extended to the entire average height of the absorbent layer (50) / channel, or only 75% of the height, or only 50% of the average height of the absorbent layer (50) / channel. This contributes to better immobilization of the absorbent material located in close proximity to said channels (26) and said channels (26) of said layers.

Adhesive material

An absorbent structural element, and / or an additional absorbent structural element, if any, may contain one or more adhesive materials (40; 60; 40 ′). Any suitable adhesive may be used, for example, so-called hot-melt adhesives may be used. In particular, spray hot melt adhesives such as HL-1620-B or HL1358LO manufactured by N.V. can be used. FullerCo. (St. Paul, Minnesota, USA).

Immobilization can be achieved by applying a thermoplastic adhesive material (40; 60; 40 ′) that holds and immobilizes the absorbent material on the backing sheet (16). Thermoplastic adhesive material may also be present in said channels (26) and on said support sheet (16). laid at the mentioned channels (waves). This adhesive material is referred to in the present description as the first adhesive material (40).

Thermoplastic adhesive material can not only facilitate the immobilization of absorbent polymer particles on the backing sheet (16), but can also help maintain the structural integrity of the channels (26) of the absorbent structure (17) / absorbent core (7) during storage and / or use of a disposable absorbent products. Thermoplastic adhesive material can inhibit the migration of significant amounts of material into the channels (26). Moreover, when applying a thermoplastic adhesive material on top of the absorbent layer (50), including in the channels (26), the adhesive can facilitate the adhesion of the support sheet (16) of the absorbent structural element (17) to the additional material, as will be described in more detail below.

In some embodiments, the thermoplastic adhesive material may be applied in the form of a fibrous layer forming a fiber network immobilizing an absorbent material on a backing sheet (16). The thermoplastic adhesive fiber layer may be partially in contact with the support sheet (16) of the absorbent structure (17).

The thermoplastic adhesive material can swell the absorbent polymer in such a way that it does not break and does not exert too much compressive force on the polymer to prevent swelling of the particles of the absorbent polymer.

Thermoplastic adhesive materials suitable for use in the present invention include hot melt adhesives containing at least a thermoplastic polymer in combination with a plasticizer and other additives, for example, thermoplastic diluents, tackifying resins and antioxidants. Examples of suitable adhesive materials are described in EP 1447067 A2. In some embodiments, In some embodiments, the thermoplastic polymer has a molecular weight of more than 10,000 and a glass transition temperature Tg lower than room temperature, typically in the range -6 ° C <T _g <16 ° C. In some embodiments, the polymer concentration in the hot melt is from about 20% to about 40% by weight. In some embodiments, thermoplastic polymers may be water insensitive. Examples of such polymers are styrene block copolymers, including three-block structures of type ABA, two-block structures of type AB and block copolymers with a radial structure (AB) _n , where A represents non-elastomeric polymer blocks, typically containing polystyrene, and blocks B are their unsaturated conjugated diene or (partially) hydrogenated derivatives. Typical examples of block B are isoprene, butadiene, ethylene / butylene (hydrogenated butadiene), ethylene / propylene (hydrogenated isoprene), and mixtures thereof.

Other suitable thermoplastic polymers are metallocene polyolefins, which are ethylene polymers prepared using a single point or metallocene catalyst. In this manner, at least one comonomer can be polymerized with ethylene to form a higher order copolymer, terpolymer or polymer. Amorphous polyolefins or amorphous α-polyolefins are also suitable. which are homopolymers, copolymers or terpolymers of C ₂ -C ₈ α-olefins.

Thermoplastic adhesive material deposited on an absorbent layer (40; 40 ′) is typically applied in the form of fibers, i.e., in a fluffy state. In some embodiments, the thermoplastic adhesive material forms a fibrous network over the particles of the absorbent polymer. The fibers can typically have an average thickness of from about 1 micron to about 100 microns, or from about 25 microns to about 75 microns, and an average length of from about 5 mm to about 50 cm. In some embodiments, a thermoplastic adhesive material is applied to the backing sheet (16) in an amount of from 0.5 to 30 g / m ² , or from 1 to 15 g / m ² , or from 1 to 10 g / m ² , or even from 1.5 to 5 g / m ² .

For an adhesive suitable for use in the present invention, the separation angle tangent at 60 ° C (tgΔ) should be lower than 1, or even lower than 0.5. The tangent of the angle of separation of the adhesive at 60 ° C (tgΔ) shows how close the state of the adhesive is to the liquid at an elevated temperature. The smaller the tgΔ, the sooner the adhesive resembles a solid, rather than the liquid, and the less its tendency to flow or migrate, and the less the tendency of the secondary structure of the adhesive in embodiments of the present invention to gradually break or even break over time. Therefore, this indicator is especially important if the absorbent product is used in a humid climate.

From the point of view of ease of processing in the manufacture of the product, or the effectiveness of the finished product, the thermoplastic adhesive material should preferably have a viscosity of from 800 to 4000 MPa · s, or from 1000 MPa · s, 1200 MPa · s or 1600 MPa · s to 3200 MPa · s , 3000 mPa · s, 2800 mPa · s or 2500 mPa · s at 175 ° C, measured according to ASTMD3236-88, at a cartridge rotation speed of 2720 rpm, after preheating for 20 minutes and stirring for 10 minutes.

The thermoplastic adhesive component may have a softening point of 60 ° C to 150 ° C, or 75 ° C to 135 ° C, or 90 ° C to 130 ° C, or 100 ° C to 115 ° C, measured according to ASTME28- 99 (Herzog method using glycerin).

In one embodiment, the thermoplastic adhesive component may be hydrophilic and have a contact angle of less than 90 °, less than 80 °, less than 75 °, or less than 70 °, measured according to ASTMD 5725-99.

Absorbent articles and diapers (1)

The absorbent core (17) of the absorbent core (7) according to the present invention can be used in an absorbent article such as a diaper (1), an example of which is shown in FIG. (1) including snap-on diapers and diapers that can be used by children or adults, as well as underwear for adults with incontinence, and similar products.

In addition to the absorbent structural element (17) or the absorbent core (7) in accordance with the present invention, the absorbent article, for example, a diaper (1), may include a top sheet and a back sheet, as well as one or more side strips (cuffs). The topsheet, cuffs or side planks may contain a skin care composition, for example, lotion or powder, known in the art, examples of which are described in US Pat. Nos. 5,607,760; 5,609,587; 5,635,191; 5643588.

The diapers (1) in accordance with the present invention preferably comprise a top sheet facing the wearer when using it, for example, a non-woven sheet, and / or a perforated sheet, for example, made of a perforated molded film, as is well known in the art, and a back sheet.

The back sheet may be liquid impermeable, as is known to those skilled in the art. In preferred embodiments, the liquid impervious back sheet comprises a thin plastic film, for example, a thermoplastic film, having a thickness of from about 0.01 mm to about 0.05 mm. Suitable back sheet materials typically contain a “breathable” material that allows air to escape from the diaper (1), but prevents fluid from the body from passing through the back sheet. Suitable films for the manufacture of the back sheet include films X15306, X10962 and X10964 manufactured by Tredegarlndustrieslnc. (Ter-Ot, Indiana, USA).

The back sheet, or any of its sections, can be elastically extensible in one or more directions. The back sheet may be attached or attached to the top sheet, an absorbent structural element (17), an absorbent core (7), or any other diaper element (1) by any attachment methods known in the art.

Diapers in accordance with the present invention may contain cuffs for the legs and / or barrier cuffs (10). Side plates and / or foot cuffs and / or barrier cuffs are arranged in pairs opposite each other along the longitudinal edges of the absorbent structural element (17) / absorbent core (7), being longitudinally extended along the mentioned absorbent structural element / absorbent core, and generally are a mirror image of each other relative to the longitudinal axis of the product. If there are both foot cuffs and barrier cuffs, then the foot cuffs are usually located outside with respect to the barrier cuffs. Leg cuffs can be extended in the longitudinal direction by at least 70% of the length of the product. The cuffs may have a loose longitudinal edge extending from the X-Y plane (formed by the longitudinal and transverse directions of the product), that is, extended in the Z direction. The cuffs may contain elastic material (11).

The diaper in accordance with the present invention may comprise a waistband, for example, a front waistband and a back waistband, which may comprise elastic material. The diaper (1) may contain fasteners (8) and a zone (9) for their fastening.

The diaper (1) may contain side panels (so-called "ears"). The diaper (1) may include fastening means for fastening the front and rear parts of the product to each other, for example, for fastening the front and rear waist belts to each other. Preferred attachment systems comprise petals and attachment zones, with the petals usually attached to the rear region of the diaper (1) and the attachment zones are part of the front region of the diaper (1).

The absorbent structural element can be used in combination with the receiving layer (12) and / or with the layer (70) of the receiving material (and, accordingly, the absorbent core (7) of an absorbent product, for example, a diaper (1), may contain them). Such a component system may contain chemically formed cross-linked cellulose fibers. Such cross-linked cellulosic fibers may have the desired absorption properties. Examples of chemically formed crosslinked cellulosic fibers are described in US Pat. No. 5,137,537. In some embodiments, the crosslinked cellulosic fibers are made using from about 0.5 mol% to about 10.0 mol%, or from about 1.5 mol% to about 6.0 mol% of a substance based on a glucose unit inducing the formation of polycarboxylic C ₂ -C ₉ cross bonds. An example of a suitable crosslinker is citric acid. In some embodiments, polyacrylic acids may be used. In some embodiments, cross-linked cellulosic fibers have a water retention rate of from about 25 to about 60, or from about 28 to about 50, or from about 30 to about 45. A method for determining water retention coefficient is described in patent 5137537. In some embodiments, cellulosic fibers with cross-linking can be wavy, twisted or twisted, or have any combination of the listed features.

In some embodiments, the upper and / or lower receiving layers may comprise a non-woven fabric, which may be hydrophilic. In addition, in some embodiments, the upper and / or lower receiving layers may contain chemically formed cross-linked cellulose fibers that may or may not form part of the non-woven fabric. In one embodiment, the upper receiving material may comprise non-woven material without cross-linked cellulosic fibers, and the lower receiving layer may comprise chemically formed cross-linked cellulosic fibers. In addition, in one embodiment, the lower receiving layer may comprise chemically formed cross-linked cellulosic fibers mixed with other types of fibers, such as. for example, natural or synthetic polymer fibers. In various embodiments, those mentioned as other, natural or synthetic polymer fibers may include fibers with a large surface area, thermoplastic binder fibers, polyethylene fibers, polypropylene fibers, PET fibers, viscose fibers, regenerated cellulose fibers, and mixtures thereof. Suitable nonwoven materials for the upper and lower receiving layers include, but are not limited to, SMS type materials (containing a spunbond fabric layer. In some embodiments, it is advisable to use stably hydrophilic nonwoven webs, in particular nonwoven webs with persistent hydrophilic coatings. In yet another in a suitable embodiment, a web of SMMS structure is used. In some embodiments, the nonwoven materials are porous.

The diaper (1) may include a sublayer located between the top sheet and the absorbent structural element (17) / absorbent core (7), which can receive, distribute and / or immobilize fluid secretions of the body. Suitable sublayers include receiving layers, buffer layers, which quench the influx of large volumes of bodily fluids, and / or feces storage layers known to those skilled in the art. Suitable materials that can be used in the sublayers can include large open cell foams, large particle foams, open or closed cell foams (macro or microporous foams), non-woven fabrics with increased airiness, polyolefin, polystyrene, polyurethane foams or particles , structures containing many vertically oriented, preferably loop-shaped, filaments or fibers, or, preferably, perforated, formed films. In the context of the present description, the term "microporous" means materials that can carry fluids due to capillary forces, but containing pores with an average size of more than 50 microns. The term "macroporous" means materials in which the pore size is too large to allow capillary transfer of fluids, and usually more than (on average) 0.5 mm in diameter, usually more than (on average) 1 , 0 mm in diameter, but less than 10 mm or even less than 6 mm (average).

Possible methods for assembling the diaper (1) in accordance with the present invention include traditional methods for the manufacture of disposable absorbent articles. So, for example, the back sheet and / or top sheet can be attached to the absorbent structural element (17) / absorbent core (7) or to each other by means of a uniform and continuous adhesive layer, or by drawing a pattern from separate lines, spirals or adhesive points . It was determined that adhesives HL-1258 or H-2031 manufactured by N.V. are satisfactory for this purpose. FullerCompany (St. Paul, Minnesota, USA). Although the top sheet, back sheet and absorbent core (7) can be assembled with each other in various conventionally used configurations, preferred diaper configurations (1) are described in US Pat. zones "(Roe et al., issued September 10, 1996), 5569234" Disposable Panties-Nappies "(Buell et al., issued October 29, 1996); and 6004306 “Absorbent article with side panels expandable in several directions” (Robles et al., issued December 21, 1999).

A method of manufacturing an absorbent structural element

The absorbent structural element in accordance with the present invention can be manufactured by any method comprising the step of applying the absorbent material to the support sheet (16), for example, first by arranging said support sheet (16) over the raised portions corresponding in shape and size to the formed channels ( 26), and then by applying said absorbent material to it, as a result of which the absorbent material does not remain on the above raised areas, but only and other parts of the supporting sheet (16).

In some embodiments, the absorbent structural element (17) with an absorbent layer (50) containing two or more channels (26), essentially not containing absorbent material, can, for example, be obtained by a method comprising the steps of:

a) providing a feeding device, for example a hopper, for supplying said absorbent material to a first endless moving surface;

b) providing means for transferring the backing sheet (16) to a second endless moving surface;

c) providing a first infinite moving surface having one or more reservoirs for forming an absorbent layer (50) having a longitudinal direction and an average length perpendicular to its transverse direction and an average width, and a depth direction and an average depth perpendicular to both of them, and a cavity volume for receiving said absorbent material therein, wherein said reservoirs in their front region comprise one or more raised strips, essentially extended in the longitudinal direction and in place which have no empty volume, each of which has an average width W of at least 4% or at least 5% of the average width of the tank, and an average length L of at least 5% and a maximum of 30% of the average tank size in longitudinal direction; wherein said one or more reservoirs are for transferring said absorbent material onto said second endless moving surface;

d) providing a second infinite moving surface having an outer shell having one or more breathable or partially breathable sockets for receiving said supporting sheet (16) in or on them, with a receiving region and with one or more substantially longitudinally mating surfaces strips which may be airtight and each having an average width W of at least 2.5 mm, preferably between 0.5 × W and 1.2 × W, and an average length L ′ of from about 0.8 × L to 1.2 × L;

wherein the breathable outer shell is connected with one or more secondary vacuum systems that ensure that the supporting sheet (16) and / or said absorbent material is held thereon, and at the same time, the said first endless moving surface is at least partially in close enough proximity to each other during the transfer of the aforementioned absorbent material, and each of the mating strips is in absolutely close proximity to the raised strip in The burden of transferring said absorbent material;

e) feeding from said feeding device of absorbent material onto said first endless moving surface into at least one or more of said reservoirs thereof;

f) as an additional possible step, removing the absorbent material from said one or more protruding strips;

g) at the same time, transferring said supporting sheet (16) to said second infinite moving surface, to said one or more slots, or to them;

h) selectively transferring at said convergence point of said absorbent material from said first endless moving surface only onto said portion of the backing sheet (16) which is located on or in said receiving region of said socket.

Said reservoirs may be formed in the form of a plurality of grooves and / or cavities having an “empty” volume and receiving said absorbent material. In some embodiments, the average width W (of each) of the strip is at least 6 mm, or at least 7 mm, and / or at least 7%, or at least 10% of the average width of the respective reservoir.

Each of these cavities and / or grooves may have a maximum dimension in the transverse direction of at least 3 mm, and the shortest distance between adjacent cavities and / or grooves in the essentially transverse direction is less than about 5 mm. Cavities and / or grooves adjacent to a raised strip may have a volume exceeding the volume of one or more, or all of their adjacent grooves or cavities that are not adjacent to a given strip or other strip (i.e., are farther from the strip )

Said reservoirs of the first infinite moving surface may be at least partially breathable, said first infinite moving surface may be a cylindrical surface with said reservoirs rotating around a stator containing a secondary vacuum chamber; wherein the outer shell of the second infinite moving surface is connected with said secondary vacuum system.

In one embodiment of the method, it is possible to manufacture an absorbent core (7) comprising two or more of the absorbent components described above; for example, two layers superimposed in such a way that the absorbent material of the first layer and the absorbent material of the outer second layer will be located in close proximity to each other between the supporting sheet (16) of the first layer and the supporting sheet (16) of the second layer.

The method may comprise an additional step i):

i) 1) applying an adhesive material (for example, a first adhesive material (40)) onto said absorbent structure (17) in step g; and / or

i) 2) applying an adhesive material (for example, a second adhesive material (60)) onto said support sheet (16; 16 ′), prior to or simultaneously with step f, but in any case before step h).

Step i) 1) may include spraying said first adhesive material in the form of fibers onto said absorbent layer, or onto a part thereof, for example, in a substantially continuous manner, so that it is also applied to said channels (26).

Step i) 2) may include applying to the support sheet (16; 16 ′) a slit method or by spraying, continuously, or, for example, in the form of a structure corresponding to the structure of the channels (26).

The method may include providing a means of applying pressure, for example, a pinch roller, which can exert pressure on the absorbent structural element (17), especially in those embodiments in which the absorbent material is located between the supporting sheet (16) and the additional material; pressure may be applied to said support sheet (16) or to any additional material or layer laid over the absorbent layer (50) as described above. The pressure should preferably be applied selectively, namely, only to the channels (26) of the absorbent structural element (17), for example, to the sections of the support sheet (16) corresponding to the channels (26), and which accordingly do not contain (on the opposite surface) the absorbent material, in order to avoid compression of the absorbent material itself. The pressure applying means may have a structure of protrusions corresponding to said structure of one or more raised strips and / or said mating strips, preferably a structure of mating strips.

The method may include the step of applying adhesive material (for example, second adhesive material 60)) to the backing sheet (16) or part thereof before applying the absorbent material / forming said absorbent layer (50) and / or applying the adhesive material (40; 40 ′) onto said absorbent layer (50), after applying / forming it on said supporting sheet (16).

The dimensions and their values contained in this document should not be construed as strictly limited to the exact values given. On the contrary, unless otherwise specified, a given value is understood to mean this value in accuracy and all values located in a functionally equivalent neighborhood. So, for example, a value designated as 40 mm should be considered as “approximately 40 mm”.

All documents cited in the detailed description of the present invention in part related to the present invention are mentioned for reference only. The citation of any document should not be construed as an admission that the cited document should be included in the prior art in relation to the present invention. If any meaning or definition of a concept in this document does not coincide with the meaning or definition of a given concept in a referenced document, one should be guided by the meaning or definition of a given concept contained in this document.

Although specific embodiments of the present invention are illustrated and described herein, one skilled in the art will appreciate that other changes and modifications are possible without violating the idea and purpose of the invention. For this purpose, it was intended in the appended claims to represent all possible similar changes and modifications within the scope of the present invention.

Claims (15)

1. An absorbent structural element (17) for an absorbent article comprising a backing sheet (16) and an absorbent layer (50) of absorbent material comprising at least a superabsorbent polymer material and optionally a cellulosic material, wherein said absorbent layer (50) is supported said supporting sheet (16) and immobilized on a supporting sheet (16); and said absorbent layer (50) has a transverse direction and an average width W, a longitudinal direction and an average length L, and a height direction (height);
and wherein said absorbent layer (50) includes a first longitudinally extended side portion located on one side of said longitudinal axis, and a second longitudinally extended side portion located on the other side of the longitudinal axis; wherein said absorbent layer (50) includes a front region, a rear region and a crotch region located between them, arranged in series in said longitudinal direction;
wherein said absorbent layer (50) includes at least a first substantially longitudinally extended channel (26) and a second substantially longitudinally extended channel (26), which essentially do not contain said superabsorbent polymeric material and are made through, extended the said height of said absorbent layer (50); wherein said first channel (26) is located only in the front region of said first side part, and said second channel (26) is located only in the front region of said second side part, and each of the channels (26) is characterized by an average width W ′ of at least 4% of the average width W of said absorbent layer (50). 2. An absorbent structural element (17) according to claim 1, characterized in that said absorbent layer (50) includes longitudinal side edges (18), a transverse front edge and a transverse rear edge (19), while the said channels (26) do not are extended to any of the longitudinal side edges and the transverse front edge of said absorbent layer (50). 3. The absorbent structural element (17) according to claim 1, characterized in that W ′ is at least 7% of W and up to 25% W or from at least 5 mm and up to, for example, 20 mm. 4. The absorbent structural element (17) according to claim 1, characterized in that the said absorbent layer (50) contains one or more additional channels (26 ′; 26 ″), essentially not containing superabsorbent polymer material, essentially extended in the longitudinal direction, and each of the additional channels (26 ′; 26 ″) is characterized by an average width W ″ of at least 4% W. 5. An absorbent structural element (17) according to claim 4, characterized in that said one or more additional channels (26 ′; 26 ″) are made at least in the crotch region of said absorbent layer (50). 6. The absorbent structural element (17) according to claim 1, characterized in that said supporting sheet (16) is laid in said first and second channels (26), and optionally, in said additional channels (26 ′; 26 ″) or their parts. 7. The absorbent structural element (17) according to claim 1, characterized in that it further comprises one or more adhesive materials (40; 60) for immobilizing said absorbent material on said supporting sheet (16). 8. Absorbent structural element (17) according to claim 7, characterized in that said one or more adhesive materials include a first adhesive material (40) deposited on said absorbent layer (50), or a part thereof, after being applied to said supporting sheet (16), wherein said adhesive is preferably a thermoplastic fibrous adhesive material. 9. The absorbent structural element (17) according to claim 7, characterized in that said one or more adhesive materials include a second adhesive material (60) located between said supporting sheet (16) and said absorbent layer (50). 10. The absorbent structural element (17) according to claim 1, characterized in that said absorbent material consists essentially of said particulate superabsorbent polymeric material. 11. The absorbent core (7) containing the absorbent structural element (17) according to any one of the preceding paragraphs, which is the first absorbent structural element (17), and containing additional material located in close proximity to the said absorbent layer (50) and selected from : i) an additional support sheet (16 ′); ii) a layer (70) of the receiving material; iii) a second absorbent structural member (15) comprising a second support sheet (16 ′) and a second absorbent layer (50 ′), said second absorbent layer (50 ′) and said absorbent layer (50) of the first element being located between said supporting a sheet (16) of the first element and said second supporting sheet (16 ′), the second absorbent structural element (15) being the same as in any of the preceding paragraphs. 12. The absorbent core (7) according to claim 11, characterized in that the said second absorbent structural element (17) is an element according to any one of paragraphs. 1-10, wherein said channels (26) of said second absorbent structural element (15) are essentially identical to and essentially overlapped with said channels (26) of said first absorbent structural element (17). 13. The absorbent core (7) according to claim 11, characterized in that said supporting sheet (16) of said first element and / or said second supporting sheet (16) are stacked in said channels (26), or a part thereof, one or both of said support sheets (16, 16 ′) optionally contain adhesive material (40; 40 ′; 60), and wherein said support sheets (16, 16 ′) are glued to each other or to said absorbent layer in said channels (26) by bonding under pressure or with adhesive material. 14. The absorbent structural element (17) according to any one of paragraphs. 1-10 or an absorbent core (7) according to any one of paragraphs. 11-13, characterized in that the portions of the material of the supporting sheet (16) corresponding to the said channels (26) are selectively pressurized to further lay said supporting sheet (16) in the said channels (26), the optionally mentioned absorbent layer ( 50) and / or said supporting sheet (16) contain one or more adhesive materials (40; 40 ′; 60) and said additional pressure applying means for fixing said supporting sheet (16) in said channels (26). 15. An absorbent article containing an absorbent structural element (17) according to any one of paragraphs. 1-10 or an absorbent core (7) according to any one of paragraphs. 11-13, wherein the absorbent article is preferably a diaper.

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