RU2393829C2 - Adsorbent product including liquid-permeable layer - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine and to an adsorbent product including at least one material of a liquid-permeable layer and an adsorbing structure, and the adsorbing structure is extensible if get wet that causes that the adsorbing structure shows the first volume in a dry condition and the second volume in a completely extended wet condition, and the second volume exceeds the first volume.

EFFECT: liquid-permeable layer surrounds the adsorbing structure so that the adsorbing structure does not reach complete extension while getting wet that in turn keeps a stable shape of the product and minimises liquid leaking.

12 cl, 3 ex, 4 tbl, 10 dwg

Description

Technical field

The present invention relates to an absorbent article including a liquid permeable surface layer and a liquid impermeable surface layer, as well as an absorbent core located between the surface layers, the absorbent core including at least one permeable layer the liquid material and the absorbent structure, the absorbent structure having the ability to expand upon wetting, which causes the absorbent structure to exhibit a first volume eat in a dry state and the second volume in a fully expanded wet state, and the second volume is larger than the first volume.

State of the art

Absorbent articles, such as diapers, incontinence protectors and sanitary napkins, are designed to receive and adsorb physiological fluids such as urine and menstrual fluid. Of course, there are products with different shapes and sizes depending on the application and the amount of fluid that the product must be capable of adsorbing. For example, diapers for adults with severe incontinence are significantly larger and more absorbent than diapers for babies. In addition to the requirements for sufficient absorption capacity and safety for leakage, there is also a requirement that the diaper is comfortable to wear. For adult users, it is also important that the products are discrete and can be worn, without paying attention to them, under ordinary clothes. An additional important criterion for absorbent articles intended for single use is that they should not take up too much space during storage, transportation and in packaging purchased by the user.

To obtain a sanitary pad that has a good fit, it is known to manufacture products with a three-dimensionally formed anatomically adjusted shape. Absorbent articles, which include rigid elements with a stable configuration, are described in SE-A-9604223-9 and SE-A-9604221-3. Configuration-stabilizing elements, or forming elements, are three-dimensional molded elements constructed from materials that resist crushing or leveling when they are subjected to forces from the user's body, for example, when the user is walking or sitting on the product. Although the three-dimensional configuration solves the problem of obtaining a good fit during the use of absorbent articles, three-dimensional absorbent articles cause significant difficulties during manufacture and storage. Three-dimensional parts are difficult to handle during the manufacturing process, for example, when they need to be assembled to obtain an absorbent product.

EP 0834296 A1 refers to an absorbent article that is flat in dry conditions, but which expands when wetted to a predetermined three-dimensional contour. The absorbent article has an expanded layer, preferably a regenerated cellulose foam, i.e. sticky foam. In addition, the absorbent article has a liquid permeable surface material. The liquid-permeable surface material has wrinkles in a dry state, the wrinkles being folded when wet so that the expanding layer can swell several times from its dry volume. However, the problem with such a product is that viscous foams are very soft after wetting. An additional problem of the known product is that viscous foams have insufficient fluid retention capacity.

Therefore, the invention aims at eliminating the problems associated with previously known expandable products. In particular, the aim of the invention is to achieve an absorbent article with a three-dimensional structure of a stable shape.

SUMMARY OF THE INVENTION

An article of the type described in the introduction is achieved by the present invention. The product in accordance with the invention makes it possible to efficiently use the absorbent capacity of the swellable absorbent product to obtain a better fit and minimize leakage.

The absorbent article includes at least one liquid-permeable layer and an absorbent structure, the absorbent structure having the ability to expand when wet and has a first volume in the dry state and a second volume in the fully expanded wet state, the second volume being larger than the first volume. The absorbent article in accordance with the invention is mainly characterized in that the material of the liquid-permeable layer constitutes a volume-limiting means for the absorbent structure so as to prevent the absorbent structure from fully expanding when wet.

Thus, the stiffness of the absorbent structure increases when it is wet, whereby the swollen absorbent structure with a volume-limiting agent in the wet state forms a forming element of a stable shape. The advantage of such a product is that it is flat until wet, but that it exhibits a more than three-dimensional shape when wet.

Thus, the material of the liquid-permeable layer defines and limits the space available for expansion for the absorbent structure. The material of the layer may be in the form of a layer of continuous material that is located around the absorbent structure in such a way that the full expansion of the absorbent structure is prevented. Alternatively, the layer material may be in the form of two or more layers of material that are joined together to form a surrounding sleeve around the absorbent structure. It is also possible to arrange the absorbent structure in the space between the material of the liquid-permeable layer and one of the other components in the absorbent product, for example, one of the protective layers of the product. It is not necessary for the invention that the expansion space is completely enclosed around the absorbent structure. For example, elongated absorbent structures can be enclosed in tubular sleeves or other open ends or open spaces. The bottom line is that swelling of the absorbent structure is prevented in the desired direction of swelling and in the desired parts of the absorbent structure.

By adjusting the size and shape of the material of the liquid-permeable layer with respect to the size and shape of the absorbent structure, it is possible to preliminarily determine the swollen / expanded shape of the absorbent structure and thus give the absorbent article a three-dimensional shape that adapts to the wearer's body or which gives the article raised barriers or other three-dimensional functional elements.

Due to the fact that the layer of liquid-permeable material limits the expansion space of the absorbent structure, the absorbent structure after wetting will be compressed with respect to the liquid-permeable layer of the material and keep it expanded in a desired predetermined form. The expansion force in the absorbent structure also causes the forming element formed upon wetting to act as a counteracting force when the forming element is subjected to compressive forces during application, for example, when the user walks or sits down. This means that the formed forming element in accordance with the invention has an extremely good ability to resist unwanted compression or other deformation.

An additional advantage associated with this type of product is that the absorbent product is flat during the manufacturing process. As mentioned above, three-dimensional parts are difficult to handle during the manufacturing process, for example, when they need to be assembled together to obtain an absorbent product.

In addition, the advantage is that the absorbent article is flat before use, since it is thus easier to pack and takes up less space in the package.

In accordance with one embodiment of the invention, the absorbent structure after wetting forms a forming element that is stable in shape. This means that the forming element is not deformed by the compressive forces acting in the product, and forces arise during normal use of the product, i.e. when the user sits, lies, stands, or moves with the product in contact with his or her body. An advantage of such an article is that, after wetting, the absorbent structure forms one or more shape-stable rigid elements that resist crushing or smoothing when they are subjected to forces from the user's body. The forming element, for example, can form a raised portion on the surface, which is coated with a liquid-permeable surface layer, or constitute an internal shape-stable element in the absorbent core.

According to a further embodiment, the absorbent structure can expand upon wetting to a maximum volume, which is 2/3 of the second volume of the absorbent structure. In order to achieve a good effect from limiting expansion, the adsorbent structure must have an expandability of 100% -5000% and preferably 200% -4000%. Expandability means the ability of the absorbent structure to increase in volume upon transition from a dry state to a wet state without limiting expansion. The ability to expand can be determined, for example, using the method of increasing the volume described below.

The absorbent structure is predominantly a polyacrylate-based foam material. A polyacrylate-based superabsorbent foam material is produced by saturating a solution consisting of at least monomers, crosslinking agents, initiators, and surfactants, and increasing its pressure with carbon dioxide in a tank with stirring. When the solution is removed from the reservoir through the nozzle, the solution expands and a foamed structure is obtained. The foamed structure is then fixed due to polymerization and crosslinking initiated by, for example, UV radiation. Finally, the material is compressed and dried. A polyacrylate foam of this type is described in detail in Example 1.

Another type of absorbent structure that can be used includes a mixture of superabsorbent material and fibers. A superabsorbent material means an adsorbent material with the ability to absorb and retain liquid several times its own mass, while at the same time forming a swollen hydrogel. The fibers preferably include absorbent fibers, such as fluff pulp, rayon, cotton or the like. It is also possible to use mixtures of non-absorbent fibers and absorbent fibers or only non-absorbent fibers. Non-absorbent fibers, for example, are various types of synthetic polymer fibers, such as polyolefins, polyester and polyamide.

It is also possible to use high density pure cellulose fiber structures. For example, the absorbent structure of a fluff pulp pulp with a density of at least 0.3 g / cm ^{3 can be used} . The structural density of the cellulose fibers is determined on a rectangular material sample in which the mass, surface and thickness of the material are measured, and the density is calculated from the measured values. The thickness of the sample is determined at a pressure of 0.5 kPa. All measurements are carried out at 23 ° C and 50% relative humidity.

The liquid permeable layer consists or includes nonwoven material. The liquid permeable material layer may also consist of or include an aperture plastic film or mesh material.

According to one embodiment of the invention, the absorbent article has two longitudinal side edges, in which, after swelling, the absorbent structure forms liquid-raised barriers along the longitudinal side edges. One advantage of such an embodiment is that the absorbent structure after the first wetting acts as raised barriers to the liquid. An additional advantage of such an embodiment is that the absorbent structure has the ability, even at first wetting, to prevent the flow of fluid along the longitudinal side edges due to the fact that the fluid is absorbed and retained by the absorbent structure.

A problem that is associated with traditional elastic flow barriers (“standing folds”) that are designed to form pockets for collecting fluid is that they can be squeezed and straightened when they are subjected to excessive external pressure. When the elastic barriers are compressed, the pockets are closed to a greater or lesser extent, as a result of which the flow of liquid into the pockets is blocked and instead it flows through the barriers. The described problem with conventional elastic flow barriers is eliminated by using raised liquid barriers in accordance with the invention, since the absorbent structure forms, after wetting, a constantly raised part that is substantially stable in shape.

According to another embodiment, the absorbent article has a thickness direction, wherein the absorbent structure has a collection area for receiving a physiological fluid consisting of at least a cavity or a region of lower density than the part of the absorbent structure that is adjacent to the collection area and located mainly on the same plane. The portion that is adjacent to the collection area includes an absorbent structure in which the absorbent structure mainly increases in diameter in the direction of the thickness of the article during wetting and the size of the collection area increases in this direction during wetting. Thus, a cavity or compartment is formed that has the ability to absorb liquid during subsequent wetting.

According to a further embodiment, the absorbent structure in a dry state has a density of at least 0.5 g / cm ³ . In accordance with a similar embodiment, the adsorbent structure in a dry state has a density that is at least 0.7 g / cm ³ . An advantage of an embodiment similar to this is that the superabsorbent foam is thin before wet.

Dry density means the density that the absorbent structure has in the absorbent article during storage of the absorbent articles, for example in a sealed package of diapers. Diaper packaging refers to the packaging in which diapers are enclosed for sale. In some cases, the diapers can be individually wrapped, and a number of individually wrapped diapers are then sealed in a larger package with diapers. The diaper packaging then refers not to the individually wrapped diaper, but to the larger outer packaging of the diapers. Similarly, if the absorbent article is an incontinence protector or sanitary napkin, the density referred to is the density that the absorbent structure has in the absorbent article during storage of the absorbent articles in an airtight container of incontinence or airtight packaging of sanitary napkins. When the density of the absorbent structure is measured, the measurement should be carried out within 2 minutes after the package is opened. Density should be measured at a load of 0.5 kPa per material.

In accordance with a further embodiment, the total absorbent capacity per cubic centimeter of the absorbent structure in the dry state is at least 15 g / cm ³ . According to a more preferred embodiment, the total absorbent capacity per cubic centimeter of the absorbent structure in the dry state is at least 27 g / cm ³ . In accordance with an even more preferred embodiment, the total absorbent capacity per cubic centimeter of the absorbent structure in the dry state is at least 35 g / cm ³ . Example 2 describes in detail how absorbent capacity is measured in an absorbent structure.

Brief Description of the Drawings

Below the invention will be described in more detail with reference to the figures shown in the accompanying drawings, in which

Figure 1 shows a sanitary napkin in accordance with the invention.

Figure 2a shows a cross section along line II-II of the sanitary napkin of Figure 1 after wetting,

Figure 2b shows a cross-section along line II-II of the sanitary napkin of Figure 1 until wet,

Figure 3 shows a diaper with liquid barriers in accordance with the invention,

Figure 4 shows a cross section along line IV-IV of the diaper of Figure 3,

5 shows an incontinence protection with a forming element consisting of an absorbent structure in accordance with the invention,

FIG. 6 shows a cross section along line VI-VI of an incontinence guard in FIG. 5,

7 shows a cross section through a test body for determining swelling,

Fig. 8 shows a schematic view of a test arrangement for measuring stiffness,

Figure 9 shows Diagram 1,

Figure 10 shows Diagram 2.

Detailed Description of Embodiments

The sanitary napkin 100 shown in FIG. 1 includes a liquid permeable protective layer 101 located on the side of the sanitary napkin that is intended to be contacted by the user during use. Examples of liquid-permeable protective layers 101 that can be used are various types of non-woven material, perforated plastic films, nets, or laminates thereof.

The sanitary napkin 100 further includes a backing layer 102 located on the side of the sanitary napkin, which is intended to be accessed by the user during use. The backing layer 102 is suitably substantially liquid impermeable or completely liquid impermeable.

The liquid-permeable backing layer 101 and the backing layer 102 are mutually connected and form a protruding connecting edge 103 around the periphery of the sanitary napkin. The bonding between the layers can be achieved by any known technology suitable for this purpose, such as bonding or welding using heat or ultrasound.

Between the liquid permeable protective layer 101 and the back layer 102, in the direction from the liquid permeable protective layer 101 to the back layer 102, there is a forming element 104, which is shown in a swollen and non-swollen state (Fig. 2a and 2b, respectively), and an absorbent body 107 .

The sanitary napkin 100 has an elongated shape with a front transverse end edge 113, a rear transverse end edge 114 and two longitudinal side edges 115, 116. The sanitary napkin 100 can also be divided into three parts with respect to how the sanitary napkin should be worn in relation to the body user. Thus, the sanitary napkin has a front end portion 111, a rear end portion 112, and a crotch portion 110 located between the end portions 111, 112.

The fastening element 108 in the form of a longitudinal rectangular region of self-adhesive adhesive is located on the surface of the back layer 102, which is drawn from the user. The bonding element 108 extends over most of the surface of the backing layer 102 between the two end edges 113, 114. Prior to use, the bonding element 108 is suitably coated with a removable backing layer, for example, silicone-coated paper.

It is possible, of course, to use other adhesive patterns than shown, such as, for example, longitudinal threads, transverse areas, dots or other shapes. Furthermore, the type of fastening means is of course not relevant to the invention, and it is possible to use friction fasteners or various types of mechanical fastening devices, such as wings or the like, alone or in combination with each other. It is also possible to do without the use of fastening devices.

The expansion and location of the forming element 104 generally corresponds to the shape and size of the crotch region 110 of the sanitary napkin 100. The forming element 104 consists of a layer 105 of liquid-permeable material and an absorbent structure 106, the absorbent structure 106 having the ability to expand when wet, which leads to that the absorbent structure 106 has a first volume in a dry state and a second volume in a fully expanded wet state, the second volume being larger than the first volume. A liquid-permeable protective layer 105 surrounds the absorbent structure 106 so that the absorbent structure 106 cannot become fully expanded when wet. It is important that the liquid-permeable protective layer 105 is arranged around the absorbent structure 106 so that the expansion space is limited by the material layer 105. This can be achieved, for example, when the material layer 105 is in the form of a solid tube or is made in the form of a tube by attaching two edges of the layer of the initially flat layer of material. It is also possible to achieve a limited expansion space by attaching the material layer 105 to another component, for example an absorbent body 107.

Due to the fact that the expansion space is limited, the absorbent structure 106 after wetting forms a raised portion which is substantially stable in shape, whereby the sanitary napkin 100 is not deformed by the compressive forces acting on the napkin 100 that occur during normal use gaskets 100. The forming element 104, after wetting, has a predetermined three-dimensional shape with a central raised portion 119 extending in the longitudinal direction nii sanitary napkins. During the application of the sanitary towel 100, the central raised portion 119 will come into contact with the user's body and will be partially inserted between the user's external labia.

The central raised portion 119 has a longitudinal shape and becomes narrower towards the end portions 111, 112 of the sanitary napkin 100. The raised portion is the highest in the area that is intended to be positioned at the vaginal opening of the wearer during use.

The absorbent body 107 is located between the forming element 104 and the backing layer 102. The absorbent body 107 is suitably composed of one or more layers of some conventional absorbent material. Examples of materials that can be used are fabric layers, cotton layers of synthetic or natural fibers, layers of fluff pulp, absorbent foam layers or the like.

Examples of materials for an absorbent structure are polyacrylate-based foam materials.

Fig. 2a shows in cross section how the forming element 104 is obtained when the absorbent structure 106 becomes wet and swells so that it fills the available expansion space outside the layer 105 of liquid-permeable material. Due to the fact that the absorbent structure 106 cannot expand freely, but is limited by a layer 105 of liquid-permeable material, this layer is held stretched so as to form a form-stable, hard raised portion 119 with low compressibility on the surface of the sanitary towel 100 that is intended to come into contact with the user's body upon application. The shape of the raised portion 119 is determined by the shape of the available space, which is limited by a liquid-permeable protective layer 105.

FIG. 2b shows an example of how the forming element 104 and the liquid permeable backing layer 105 can be positioned before they get wet. The liquid-permeable backing layer 105 has a bent portion 109 that can expand when the adsorbent structure 106 swells. An alternative or additional way to create an expansion space is to form a liquid-permeable backing 105 from a tensile material with limited and predetermined extensibility. In both cases, the expansion space can be used so that the absorbent structure cannot expand completely.

The diaper 300 shown in FIGS. 3 and 4 has a conventional basic structure and includes a liquid permeable protective layer 301, a liquid impermeable back layer 302, and an absorbent body 307 disposed between the liquid permeable protective layer 301 and non permeable a liquid backing layer 302. A liquid-permeable backing layer 301 is suitably soft, skin-friendly and plastic material of a non-woven material, a perforated plastic film, mesh or the like. It is generally accepted to use polymeric materials that are themselves hydrophobic, but which are processed to produce a hydrophilic surface so that liquid can pass through the layer. A material with a hydrophilic surface of this type is advantageous since it does not adsorb liquid and thus maintains a dry surface. You can also apply various types of laminates and combinations of various non-woven layers and / or layers of plastic film. A thin plastic film is typically used as the liquid impermeable backing layer 302, but it is also possible to use laminates and combinations of plastic films and non-woven, hydrophobic non-woven materials or the like. An advantage is if the backing layer has a certain breathability so that air and water vapor can pass through the layer.

The absorbent body is also part of the traditional type and may thus consist of one or more layers of absorbent material, for example a pulp pulp with or without superabsorbents. The absorbent body may also include fluid collection layers, fluid distribution layers, stabilizing elements, binders, etc.

The diaper 300 has an hourglass shape with a longitudinal direction and a transverse direction and can be divided in the longitudinal direction into a wider front part 311 and a rear part 312, as well as an intermediate narrower crotch portion 310. In addition, the diaper has a front transverse end edge or edge waist 313, the rear transverse end edge or the edge of the waist 314 and two longitudinal side edges 315, 316.

To enable the diaper to be fastened together in a panty shape around the lower body of the wearer, the diaper is provided with two fastening valves 317, 318 protruding from any side edge 315, 316 parallel to the rear edge of the waist 314.

When the diaper 300 is put on, it is located with the front 311 above the wearer's stomach, the back 312 above the wearer's buttocks and the gusset between the user's legs. The diaper 300 is then secured around the wearer's waist with fastening valves 317, 318, which are taken over the front 311 and fastened to the receiving area 320 on the outside of the front 311. The fastening valves may be adhesive tape valves or include one part of the fastening device hook-loop type. Most often, fastening valves are provided with hook-type fasteners of a hook-and-loop fastening device, and the receiving region has corresponding loop-type elements. They can be in the form of a nonwoven fabric with fibrous loops for which hook elements can engage. If the outer surface of the diaper consists of such a non-woven material, a special receiving area is not required. In the same way, a special receiving area for adhesive fastening valves can be dispensed with if the outer surface is a plastic film which itself has sufficient strength to withstand attachment and preferably also opening and re-closing the valves from the tape.

The fastening element shown in the form of fastening flaps 317, 318 is, of course, not necessary for the invention; it is possible to use other suitable fastening elements such as belts, buttons, eye-hooks or the like.

In order to ensure a good fit and increase reliability against leakage, the diaper 300 is provided with leg bands 321, 322 in the form of elastic threads or strips that are pre-stretched along those parts of the side edges 315, 316 that form the leg openings when the diaper 300 is worn Accordingly, an elastic band or the like is located along the rear edge of the waist 314 and forms an elastic band at the waist 323. The diaper 300 is shown in the figures with elastic elements 321, 322, 323 in a stretched state. When the stretch stops, the elastic comes together and gives the diaper a three-dimensional shape with wrinkled edges.

According to the invention, the diaper also has two longitudinal fluid barriers 324, 325 located in the longitudinal direction on each side of the central region 326 for collecting fluid on the diaper. The liquid barriers each include a layer 305 of liquid-permeable material, which is formed in a tunnel around the absorbent structure 306, as can best be seen in FIG. 4. In the example shown, barrier tunnels are formed on separate strips of material that are fastened, for example, by means of glue or ultrasonic welding on the surface 301 of a liquid-permeable protective layer. Alternatively, it is possible to form barrier tunnels on the liquid-permeable protective layer 301 and to exclude special material bands.

In the example shown, the absorbent structure 306 extends only within that part of the diaper 300 that is located around the leg openings when using the product. Therefore, the absorbent structure 306 is located in the crotch portion 310 and is pulled a short distance into the front portion 311 and the rear portion 312, respectively. The embodiments shown provide good safety against leakage with raised barriers around the foot edges, but leave the front and back parts 311, 312 of the diaper smooth and in contact with the wearer's body when used.

Naturally, it is possible to place extended barriers over a greater or lesser portion of the diaper length than shown. It is also possible to place swellable barriers at the edges of the diaper’s waist or as fluid control elements somewhere on the liquid-permeable surface of the diaper, where it is desirable to direct the fluid flow. For example, it is possible to create channels in order to bring the fluid to the end parts of the diaper by arranging parallel expandable barriers on the wetting area of the diaper, i.e. on the part of the diaper that is designed to wet the first with physiological fluids. When the user releases liquid into the wetting area, the barriers swell and form channels for transferring the liquid to each other.

FIG. 5 and 6 show an incontinence guard 500 including a liquid permeable backing layer 501 and a liquid permeable backing layer 502 that are mutually joined at the connecting edge 503 and together surround the absorbent body 507 and the forming member 504. The forming member 504 consists of a layer of an absorbent structure 506, which is sandwiched between two layers 505 ', 505' 'of liquid-permeable material, which are joined together, for example by gluing or welding. The forming member 504 is disposed on the absorbent body 507 between the absorbent body and the liquid permeable backing layer 501 and serves as an element for transferring liquid to the absorbent body 507. The absorbent body 507 suitably consists of an absorbent material with high adsorption capacity and retention capacity for example mixtures of fluff pulp and superabsorbents. Due to the fact that the absorbent structure 506 itself has good absorbent capacity, the absorbent capacity obtained by the forming member 504 may be sufficient for certain applications, for example, for incontinence protectors intended for use with mild incontinence. In such an embodiment, the absorbent body 507 can be eliminated or formed as a thin protective material with a low absorbent capacity, for example, a fabric material.

The incontinence guard 500 is an hourglass with two end parts 511, 512 and an intermediate gusset part 510, as well as transverse end edges 513, 514 and longitudinal side edges 515, 516.

Like the sanitary napkin 100 shown in FIGS. 1 and 2, the incontinence guard 500 is provided with an adhesive fastener on the outside of the liquid impermeable back layer 502.

A forming element 504 is provided with a series of through holes 530, 531. In the example shown, the holes pass both through the layers 505 ', 505' 'of the liquid-permeable material and through the adsorbent structure 506, but it is possible to alternatively arrange the holes only through the absorbent structure 506. Holes 530, 531 may be of any suitable shape and may also be in the form of channels. The number and size of holes can also be varied within the scope of the invention. By choosing the location, size and relative distance between the openings, it is possible to achieve different degrees of containment of expansion in different parts of the absorbent structure. As a result, the absorbent structure has different stiffness in different areas after swelling. Thus, it is possible to obtain a forming element that has varying flexibility and is therefore molded or deformable to various degrees in different areas. Typically, holes located close to each other give greater rigidity in the area between the holes than holes located far enough from each other. Therefore, it is possible to create an absorbent article that itself optimally adapts to the shape of the user's body due to the flexibility of the forming element.

Two oval holes 530 are located in the crotch portion 510 of the incontinence guard 500 and three circular holes 531 are located on each end portion 511 on the incontinence guard. When the liquid comes into contact with the incontinence guard 500 and is adsorbed by the absorbent structure 506, the absorbent structure swells in the thickness direction of the incontinence guard, as shown in FIG. 6. Holes 530, 531 thus form fluid collection compartments, which can function as temporary reservoirs for a liquid that has not yet been adsorbed by the underlying adsorbent body 507. When the adsorbent structure 506 expands, the space between the layers 505 ′, 505 ″ is permeable to The liquid material is filled until these layers limit further expansion. The stiffness of the expanded material is thus increased so that the forming member 504 after expansion also prevents undesired uncontrolled compression and deformation of the incontinence guard. The location of the oval holes 530 may mean that the holes can also serve as longitudinal curved indicators for the incontinence guard 500 so that the parts between the holes 530 and the side edges 515, 516 are bent when the incontinence guard 500 is squeezed between the legs of the user when applied . The flap portion 510 of the incontinence guard is thus obtained in the form of a bowl adapted to collect liquid.

Therefore, the invention makes it possible to create an element for collecting liquid, which also serves as a forming element for an absorbent product in use.

The described embodiments should not be considered to limit the invention, they are only examples of carrying out the invention. The expandable forming elements in various embodiments can, of course, be applied to other types of absorbent articles than those described. Of course, it is also possible to combine the various forming elements with each other.

Example 1 - Measurement of expansion of foam

When the expansion was measured in the direction of the thickness of the material, the samples were stamped with a known diameter. The diameter (d _t ) and the thickness (t _t ) in the dry state were measured. Samples were then allowed to swell for 1 minute in a NaCl solution (0.9 weight percent NaCl). Then measured the diameter (d _v ) and thickness (t _v ) in the wet state.

Then calculated the percentage expansion of the thickness (TE), the percentage expansion of the area (AE) and the percentage expansion of the volume (VE) in accordance with the following formulas.

TE = (t _v -t _t ) / t _t100

AE = (d _v ² -d _t ² ) / d _t ² · 100

VE = (t _v d _v ² -t _t d _t ²⁾ / _t t d t ² · 100

The material that was tested is polyacrylate-based foam, which is referred to as Foam XII. Foam XII made in accordance with the description below.

The following ingredients were added to the beaker:

- 348.5 grams of acrylic acid (4.84 mol),

135.5 grams of sodium acrylate solution 37.3 weight percent (0.54 mol),

- 28.0 grams of polyethylene glycol diacrylate from polyethylene glycol with a molar mass of 400,

- 21.3 grams of an aqueous solution of 15 weight percent, which contains ethylene oxide and linear C16C18 fatty alcohol (molar ratio 80: 1),

- 65.7 grams of water.

All were mixed. Then the solution was cooled to a temperature below 16 degrees Celsius. Then the solution was poured into a sealed container, after which the solution was saturated with carbon dioxide at a pressure of 12 bar for 25 minutes. At the same pressure, 26.7 grams of an aqueous solution was added containing 3 weight percent 2,2'-azobis (2-amidinopropane) dihydrochloride. They were mixed to form a homogeneous solution. The solution was then allowed to calm down for 5 minutes. Then the saturated solution was poured out of the container by means of a nozzle with a hole, which was 1 mm at a pressure of 12 bar.

The resulting monomeric foam was placed on a glass plate (DIN-A3). Then an additional glass plate was placed over the monomeric foam. After that, the foam was polymerized using a UV / VIS lamp, a UV 1000 lamp from Höhnle company. The foam was lit with a lamp both from below and from above. Lighting and thus polymerization was allowed to continue for 4 minutes.

Results for Foam XII:

d _t t _t d _v t _v TE Ae Ve 28 3.8 62 6 58 357 622 28 3.8 61 6 58 390 577 28 3.8 62 6 58 390 649

The expansion in thickness will preferably be 40-80%, the expansion in area will preferably be 300-400%, and the expansion in volume will preferably be 500-800%.

Example 2 - Adsorption capacity

The total adsorption capacity per unit volume of the adsorbent structure under dry conditions was determined for five different samples.

Sample A is a mixed structure of a chemically obtained pulp from Weyerhauser and a particulate polyacrylate superabsorbent from BASF. The mixed structure contains 40 weight percent superabsorbent material relative to the total weight of the sample.

Sample B is a fibrous structure from Weyerhauser. The fibrous structure contains 80 weight percent crosslinked cellulose and 20 weight percent thermal fibers.

Sample C is a polyester fibrous layer with a particulate polyacrylate superabsorbent bonded to a polyester fibrous layer. In relation to the total mass of the sample, the proportion of superabsorbent based on polyacrylate is 60 percent.

Sample D is a foamed layer of a polyacrylate-based superabsorbent. The foamed sample is designated Foam XII and is described in detail in Example 1.

Sample E is viscose foam, i.e. regenerated cellulose foam.

The measurements were carried out during the first weighing of a dry sample. Then, the volume of the dry sample was obtained by dividing the mass of the dry sample by the density of the dry sample. Then the sample was saturated with a NaCl solution of 0.9 weight percent. The sample was supplied with an excess of NaCl solution and was allowed to adsorb the liquid for 20 minutes. Then the saturated sample was weighed. The amount of liquid that was adsorbed was obtained by subtracting the mass of the dry sample from the mass of the saturated sample.

The total adsorption capacity, measured in grams of liquid per cubic centimeter of absorbent material in the dry state, was as follows.

Adsorption capacity (gram fluid / cm ³ )

Sample ρ = 0.50 g / cm ³ ρ = 0.71 g / cm ³ ρ = 0.91 g / cm ³ Sample A fifteen 19 22 Sample B 6 6 8 Sample C fourteen twenty 26 Sample D 27 38 49 Sample E fourteen twenty 26

The results undoubtedly show that Foam XII has a large total adsorption capacity, measured in grams of liquid per cubic centimeter of adsorbent material in a dry state.

Example 3 - Stiffness of samples of the main parts with limited expansion space

To study the change in stiffness and thus the stability of the shape of the absorbent material, which is allowed to adsorb liquid under conditions where the ability to expand the absorbent material is limited in accordance with the invention, the following test was carried out.

Samples of the main parts were obtained from various adsorbent materials. The samples of the main parts were rectangular with a width of 0.01 m and a thickness of 0.0044 m. The length of the sample is not critical until it exceeds 0.04 m. The samples of the main parts were enclosed in a liquid-permeable non-woven sleeve in tube shape, as shown in FIG. 7. The diameter of the sleeve 702 was chosen so that the specimen 701 remained in a precisely predetermined and limited expansion space limited by the excess material length L _w , which is shown in FIG. 7 between one of the ends of the sample and a weld seam 703 located to fasten the sleeve to tube around the sample. Since the thickness of the dry samples is negligible in these circumstances, the length L _w gives a good measurement of the available space for expansion.

Tested 12 samples:

a) samples 1, 3, 5, 7, 9 and 11 consisted of a mixture of superabsorbent and chemical fluff pulp in a ratio of 50/50 weight percent. The fluff pulp was southern pine NB 416 from Weyerhauser and the absorbent was BASF 7160. The nonwoven used as a sleeve around the samples of the main parts was polypropylene spun material with a base weight of 16 g / m ² from BBA Nonwovens, France .

b) samples 2, 4, 6, 8, 10 and 12, consisting of Foam XII in accordance with Example 1, were enclosed in a non-woven sleeve of the same type as in a), i.e. polypropylene spun material with a base weight of 16 g / m ² from BBA Nonwovens, France.

Test for adsorption capacity and volume of closed samples

I. Adsorption capacity

Dry sample was weighed: w ₁ .

The thickness and width of the dry sample were measured.

The sample was placed in a 0.9% NaCl solution plate and allowed to adsorb for 5 minutes.

The sample was removed from the liquid and weighed: w ₂ .

The sample was removed from the pan and the amount of liquid remaining on the pan was noted: w ₃ .

The amount of NaCl solution that is adsorbed in grams per gram was calculated by subtracting the dry mass of the sample (w ₁ ) and the mass of liquid remaining on the weighing pan (w ₃ ) from the mass shown on the balance (w ₂ ):

adsorption (g / g) = (w ₂ -w ₁ -w ₃ ) / w ₁ .

Two samples of the main parts were tested for each sample.

The test results are presented in Table 1 (a mixture of superabsorbent and mass) and in Table 2 (superabsorbent foam).

Table 1 Sample Dry weight W ₁ (g) Dry sample width + nw (L _w ) (mm) The mass after adsorption W ₂ (g) Weight remaining on the weighing pan, W ₃ Adsorbed mass (g / g) Wet volume (cm ³ ) Dry thickness (mm) 1-1 1,08 10 + 0 10.55 0.21 8.6 10 4.3 1-2 1.05 10 + 0 10.21 0.22 8.5 9 3-1 2.20 10 + 2 11.78 0.30 9,4 eleven 4.4 3-2 1,08 10 + 2 12.89 0.43 10.5 12 5-1 1.14 10 + 4 14.77 0.54 11.5 fourteen 4.2 5-2 1,11 10 + 4 14.31 0.15 11.8 fourteen 7-1 1.17 10 + 6 17.05 0.17 13,4 fourteen 4.4 7-2 1.17 10 + 6 16.59 0.26 13.0 16 9-1 1.18 10 + 8 18.02 0.45 13.9 17 4.25 9-2 1.19 10 + 8 18.66 0.29 14,4 eighteen 11-1 1.21 10 + 10 20.95 0.52 15.9 twenty 4.4 11-2 1.15 10 + 10 20.79 0.45 16.7 twenty

table 2 Sample Dry weight W ₁ (g) Dry sample width + nw (L _w ) (mm) The mass after adsorption W ₂ (g) Weight remaining on the weighing pan, W ₃ Adsorbed mass (g / g) Wet volume (cm ³ ) Dry thickness (mm) 2-1 0.78 10 + 0 7.69 0.60 8.1 7 3.4 2-2 0.76 10 + 0 6.91 0.18 7.9 7 4-1 0.77 10 + 2 8.84 0.24 10,2 9 3.4 4-2 0.78 10 + 2 8.52 0.13 9.8 8 6-1 0.81 10 + 4 10.99 0.10 12,4 eleven 3.4 6-2 0.78 10 + 4 12.48 0.32 14.6 12 8-1 0.80 10 + 6 12.54 0.38 14.2 12 3.4 8-2 0.84 10 + 6 13.63 0.39 14.8 13 10-1 0.82 10 + 8 16.55 0.50 18.6 16 3.4 10-2 0.82 10 + 8 14.89 0.34 16.7 fifteen 12-1 0.86 10 + 10 18.49 0.91 19,4 eighteen 3.4 12-2 0.89 10 + 10 17.93 0.81 18.2 eighteen

II. Volume increase

The sample was obtained by wetting with an excess of NaCl solution for 5 minutes so that the samples adsorbed the liquid and expanded.

A 100 ml beaker was filled with 70 ml of 0.9% NaCl solution.

The liquid-saturated swollen samples of the main parts were lowered into a beaker and an increase in volume was noted.

The measurement method can be adapted to the size of the sample. Larger or smaller beakers can be used, as well as different amounts of liquid.

The percentage increase in volume was calculated both on the basis of the adsorbed amount of liquid in grams / gram in accordance with method I, and on the basis of determining the displaced liquid in accordance with method II. As can be seen from Table 3 and Table 4, the methods give comparable results.

For the test materials, full expansion was achieved when L _w was 10 mm (10 + 10 in the tables), and there was essentially no expansion when L _w was 0 mm.

Table 3
Calculation of extension constraint In relation to the increase g / g In relation to fluid displacement In relation to the increase g / g In relation to fluid displacement Sample Average value Average value 49% fifty% 49% 53% one 49% 55% 43% 45% 40% 43% 3 37% 40% 31% thirty% thirty% thirty% 5 thirty% thirty% twenty% thirty% 21% 25% 7 22% twenty% 17% fifteen% fifteen% 13% 9 13% 10% 5% 0% 2% 0% eleven 0% 0%

Table 4
Calculation of extension constraint In relation to the increase g / g In relation to fluid displacement In relation to the increase g / g In relation to fluid displacement Sample Average value Average value 58% 61% 59% 61% 2 60% 61% 48% fifty% 49% 53% four fifty% 56% 36% 39% thirty% 36% 6 25% 33% 27% 33% 26% 31% 8 24% 28% four% eleven% 9% fourteen% 10 fourteen% 17% 0% 0% 3% 0% 12 6% 0%

Stiffness determination

The stiffness and shape stability for swollen samples was measured by determining the elastic modulus for samples using Instron 4301H1120, Software: Series IX.

Hardness was determined at 23 ° C and 47% humidity.

A test arrangement diagram is shown schematically in FIG. The swollen sample 801 was placed on two racks 802 located at a distance L = 0.03 m from each other. The test was carried out with a compression speed of 100 mm / min, and the elastic modulus E was calculated as a function of the compression force F and the curvature d of the sample as follows:

E = F · L ³ / d · 48 · I (N / m ² ).

where I is the moment of inertia and L is the distance between racks 802.

Diagram 1 and Diagram 2 show the modulus of elasticity E for various samples as a function of percent expansion restriction. As can be seen in the diagrams, the elastic modulus and, thus, the stiffness of the sample increases as the space for expansion decreases.

An alternative method for assessing suppression of expansion; adsorption test for closed and open samples

Weigh dry, closed sample: w ₁ .

Place the sample in a cup and add an excess of 0.9% NaCl solution over 5 minutes.

Remove sample from liquid and weigh wet sample: w ₂ .

Remove the sample from the weighing pan and note how much liquid remains on the weighing pan: w ₃ .

Calculate how much NaCl solution is adsorbed by the sample in grams per gram when subtracting the dry mass of the sample (w ₁ ) and the mass of the remaining liquid (w ₃ ) from the mass shown on the balance (w ₂ ):

adsorption (g / g) = (w ₂ -w ₁ -w ₃ ) / w ₁ .

Weigh a polyester net, e.g. PE59HN from J.H. Tidbeck AB. This is a standard material that is used for various types of adsorption tests, for example in the so-called tea bag method. The mesh should be large enough to be able to hold a fully swollen sample in liquid.

Open the sleeve or expansion-limiting material of the sample and place the sample on a polyester mesh.

Place the polyester mesh with the sample in a cup with a 0.9% NaCl solution and make sure that the sample has constant access to liquid. Allow the sample to adsorb for 5 minutes.

Lift the polyester mesh with the sample and weigh it: w ₄ .

Remove the sample from the weighing pan while scraping the sample from the wet polyester net and note the weight of the polyester net and the liquid remaining on the weighing pan: w ₅ .

Calculate how much NaCl solution is adsorbed by the open sample in grams per gram by subtracting the mass of the dry sample (w ₁ ) and the polyester net and the remaining liquid (w ₅ ) from the mass (w ₄ ) of the wet fully expanded sample and dividing this result by the mass (w ₁ ) dry sample.

Adsorption g / g = (w ₄ -w ₁ -w ₅ ) / w ₁ .

The described method can be used, for example, to assess the restriction of expansion in a sample that is taken from an absorbent article. If only the measurement of the ability to fully expand the sample is of interest, the first swelling stage restricting the volume can be excluded. The sleeve of the dry sample is then cut out and placed directly on the polyester mesh, after which the test is carried out with swelling and weighing, as described above.

Samples taken from existing absorbent products

To measure expansion restrictions and stiffness in existing absorbent articles, measurements can be made either on all expansion-restricted elements in the product, or on parts of similar elements where samples can be taken from the product without breaking expansion-restricting means. For example, such a partial element may be a piece of one of the raised swellable fluid barriers 324, 325 of FIG. 3 or a divided and bounded portion between the oval openings 530 of FIG. 5.

Claims (12)

1. An absorbent article including a liquid-permeable surface layer (101, 301, 501) and a liquid-impermeable surface layer (102), as well as an absorbent body (107, 307, 507) located between the surface layers, the absorbent article comprises a layer (105, 305, 505 ', 505' ') of a liquid-permeable material and an absorbent structure (106, 306, 506), the absorbent structure (106, 306, 506) having the ability to expand when wet and exhibits a first volume in a dry state and a second volume in a fully expanded wet state, wherein the second volume is larger than the first volume, characterized in that the material of the liquid-permeable layer (105, 305, 505 ', 505``) represents a volume-limiting agent and defines a space for expansion for the absorbent structure (106, 306 , 506) so that the full expansion to the second volume is prevented when the absorbent structure is wet (106, 306, 506) so that the absorbent structure (106, 306, 506) after wetting has greater rigidity than in the dry state, and the absorbent structure (106, 306, 506) can expand and get wet to the maximum volume, which is 2/3 of the second volume of the absorbent structure (106, 306, 506). 2. The absorbent product according to claim 1, characterized in that the absorbent structure (106, 306, 506) includes a foam material based on polyacrylate. 3. The absorbent article according to claim 1, characterized in that the absorbent structure (106, 306, 506) includes a mixture of fibers and superabsorbent materials. 4. The absorbent product according to claim 3, characterized in that the fibers include absorbent fibers. 5. The absorbent product according to claim 4, characterized in that the absorbent fibers include a fluff pulp. 6. An absorbent product according to any one of claims 1, 4 or 5, characterized in that the layer (105) of liquid-permeable material includes a non-woven material. 7. An absorbent article according to any one of claims 1, 4 or 5, characterized in that the material (105) of the liquid-permeable layer includes a perforated plastic film. 8. An absorbent article according to any one of claims 1, 4 or 5, characterized in that it has two longitudinal side edges (315, 316) and the absorbent structure (306) forms raised liquid barriers (324, 325) located along the longitudinal lateral edges (315, 316). 9. An absorbent product according to any one of claims 1, 4 or 5, characterized in that it has a thickness direction and comprises a forming element (504) having a collection area (530, 531) for receiving physiological fluid, consisting of at least at least from a cavity or region with a lower density than the part of the forming element (504), which is adjacent to the collection area (530, 531) and is located in the same plane, while the part that is adjacent to the collection area (530, 531), includes an absorbent structure (506), where the absorbent structure (506) increases in diameter in the direction of the thickness of the product during wetting, and the size of the collection area (530, 531) increases in this direction during wetting. 10. An absorbent product according to any one of claims 1, 4 or 5, characterized in that the absorbent structure (106; 306; 506) in a dry state has a density that is at least 0.5 g / cm ³ . 11. The absorbent product according to any one of claims 1, 4 or 5, characterized in that the absorbent structure (106; 306; 506) in a dry state has a density that is at least 0.7 g / cm ³ . 12. An absorbent product according to any one of claims 1, 4 or 5, characterized in that the total adsorbing capacity of the adsorbent structure (106; 306; 506) in a dry state per cubic centimeter is at least 15 g / cm ³ .

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