An absorbent structure in an absorbent article, comprising a partially neutralised superabsorbent material, and an absorbent article that comprises the absorbent structure

(54) (56) (57)

INVENTOR INVENTOR

REPRESENTATIVE TITLE (51) International class ⁷

A61L 15/60 (45) (41) (22) (24) (62) (86) (86) (83)

Patent granted (21) Patent Application 2000-09-04 number 9804361-5

Application widely available 2000-06-17 17 The patent application was filed on 12/12/98

Running day 1998-12-16

Tribal application number

International filing day

Filing date for European patent application

Deposition of microorganism (30) Priority tasks

Application received as:

yl Swedish patent application completed international patent application - with number □ converted European patent application with number

SCA Hygiene Products AB, 405 03 Gothenburg SE

Berith Porsö, Party SE Marie-Louise Lagerstedt Eidrup, Billdal SE, Ulrika Hagrud, Gothenburg SE, Jan Hansson,

Lindome SE

Albihns Patentbyrå Stockholm AB

Absorbent structure in an absorbent article, comprising a partially neutralized superabsorbent material, and an absorbent article comprising the absorbent structure

CALLED PUBLICATIONS:

EP A2 0 202 126 (A61L 15/00),

EP A2 0 391 108 (C08F 283/06) SUMMARY:

Absorbent structure in absorbent articles such as diaper, incontinence cover, sanitary napkin, panty protection or the like, comprising at least 40% by weight of superabsorbent material, based on the total weight of the absorbent structure in the dry state or regions where the superabsorbent material is distributed, wherein the superabsorbent material is distributed. the material is only partially neutralized.

Absorbent articles comprising the absorbent structure.

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The numbers in brackets indicate international identifiers! code, INID code. Letters in clamps indicate international document code.

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The present invention relates to an absorbent structure of an absorbent article such as a diaper, diaper pant, incontinence cover, sanitary napkin, pantyhose or the like, comprising a partially neutralized superabsorbent material, and an absorbent article comprising the absorbent structure.

Background

An absorbent article usually consists of an upper liquid-permeable layer, an absorbent layer, and a lower liquid-impervious barrier layer, which are defined by two transverse edges and two longitudinal edges. The article comprises the front and rear portions and a branch portion located therebetween with a wetting zone within which the bulk of the body fluid is discharged. The absorbent layer often comprises a superabsorbent material.

The superabsorbent material is in particulate form, for example, granules, granules, flakes or fibers, and is mixed or layered with other absorbent material, usually cellulose fibers. Superabsorbents are polymers with high ability to absorb liquid such as water and body fluids, such as urine and blood, during swelling and forming a non-water-soluble gel. Furthermore, some have the ability to retain absorbed fluid even when exposed to external pressure. They have been widely used in absorbent hygiene products such as diapers, sanitary napkins, incontinence protectors and the like.

The effectiveness of a superabsorbent is dependent on many factors, such as where and how the superabsorbent is blended into the absorbent structure, particle shape and particle size, as well as physical and chemical properties such as absorption rate, gel strength and liquid holding capacity. A phenomenon that

513 374 called gel blockage can adversely affect absorption capacity. Gel blocking means that the superabsorbent material, upon wetting, forms a gel which blocks the pores in the fiber structure or between the particles, making the fluid transport from the wetting area out to the rest of the absorption body. This results in poor utilization of the absorption capacity of the absorption body and entails a risk of leakage.

For example, to reduce the problem of gel blocking, it is known to use superabsorbent particles which are surrounded by a casing which is only slowly dissolved in and / or penetrated by the liquid to be absorbed so that the superabsorbent material exhibits a delayed activation time. WO 95/00183 discloses absorbent articles having an absorbent structure comprising superabsorbent materials with a delayed activation time at the wetted region of the structure, and conventionally superabsorbent materials in areas outside of wetted areas.

Another way to reduce the problem of gel blocking is to use superabsorbent which exhibits high gel strength. Superabsorbents that exhibit high gel strength are able to retain absorbed liquid at external load against the swollen material, and also have the ability to absorb a significant amount of liquid at external load. EP 0 339 461 discloses superabsorbent for use in absorbent articles which exhibit high gel strength. This has the ability to maintain its shape to a greater extent and not collapse when swelling.

Furthermore, EP 0 532 002 discloses superabsorbent materials which exhibit high gel strength and also some liquid spreading ability.

Thus, a problem with absorbent articles, including superabsorbent, is gel blocking as described above. This results in an increased risk of liquid leakage, as well as a poor utilization of the total capacity of the absorbent structure. Another disadvantage of conventional superabsorbent is that it swells a lot. If you have high concentrations of superabsorbent, it can produce

513 374 unpleasant to wear after wetting, as a swollen "lump" can form in the wetting point.

The object of the invention is to solve these problems.

Brief description of the invention

The invention relates to an absorbent structure comprising only partially neutralized superabsorbent, which does not swell as much as conventional superabsorbent material, thereby enabling higher concentrations of superabsorbent. In addition, the partially neutralized superabsorbent absorbs liquid more slowly, causing the fluid to spread more before the superabsorbent swells, compared to a conventional superabsorbent. Conventional superabsorbent material has a degree of neutralization of about 70%.

The invention relates to an absorbent structure in absorbent articles such as diapers, diapers, incontinence covers, sanitary napkins, panty covers or the like, comprising at least 40% by weight of superabsorbent material, based on the total weight of the absorbent structure in the dry state or regions where the superabsorbent material is distributed, the superabsorbent having a degree of neutralization between 20 and 50%.

The invention also relates to an absorbent article comprising the absorbent structure.

By the present invention, it is possible to obtain an absorbent article which is thin, which means that an article according to the invention feels comfortable and discreet to wear. A further advantage of the partially neutralized superabsorbent is that it prevents bad odor and skin problems associated with the use of the absorbent product.

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Figure Description

Fig. 1 shows a bag used in experiments in Example 1.

Fig. 2 shows the results of Example 1 in the form of a curve where the absorption is plotted against time.

Description of the invention

The invention relates to an absorbent structure comprising partially neutralized superabsorbent material, which solves the problem in that a partially neutralized superabsorbent material does not swell as much and absorbs the liquid more slowly than a conventional superabsorbent material, i.e. a superabsorbent material neutralized to about 70%.

A suitable, partially neutralized, superabsorbent material which can be used in accordance with the invention may be, for example, a cross-linked polyacylate of the kind disclosed in European Patent EP 0 391 108, Casella AG.

Such a superabsorbent does not swell as much, that is, exhibits a lower total liquid absorption capacity, which means that the superabsorbent in a swollen state occupies a smaller volume than superabsorbent material with a higher degree of neutralization. In this way, the risk that the superabsorbent material, in the swollen state, impedes the transport of fluid in the pore structure surrounding the superabsorbent material (s) is less. Furthermore, a superabsorbent material according to the invention absorbs liquid more slowly than a superabsorbent material with a higher degree of neutralization. Because the superabsorbent absorbs liquid more slowly, a greater amount of the liquid has the possibility of spreading from the wetting point to the other parts of the absorbent structure, which results in a higher utilization of the total absorbent of the product.

513 374 capacity. Examples which follow in the description show that the partially neutralized superabsorbent material of the invention absorbs more slowly and absorbs less liquid than conventional superabsorbent material.

The superabsorbent consists of cross-linked polymerized acrylic acid. Upon neutralization, ionic complexes are formed by COO 'and Na⁺ or K⁺. Upon absorption, an ion exchange takes place between Na⁺ and other ions. The partially neutralized superabsorbent contains fewer ions (COO ') than the conventional superabsorbent. The ions (COO ') are available to absorb liquid and fewer such result in the partially neutralized superabsorbent having a slightly lower capacity. A greater number of carboxylic acid groups will be present and these do not contribute to the absorption, but they provide a lower pH than that of a conventional superabsorbent.

Since the superabsorbent of the invention absorbs lesser amount of liquid, one can have a higher concentration of superabsorbent without the product becoming uncomfortable to carry after wetting. According to the invention, more than 40% by weight of superabsorbent material, based on the total weight of the absorbent structure in the dry state or regions in which the superabsorbent material is distributed, can now be used, of the partially neutralized superabsorbent material, without the problems described above being equal. High grade.

The problems mentioned above are thus solved in that the superabsorbent is partially neutralized. The degree of neutralization is 20 to 50%, compared to a degree of neutralization of conventional superabsorbent materials of about 70%.

Superabsorbent used in the absorbent structure of the invention, which is partially neutralized, has, as previously mentioned, a lower absorption capacity and is slower to absorb liquid. As the superabsorbent absorbs more slowly, the liquid will have more time to absorb

513 374 spread in the absorbent layer. Thus, the superabsorbent particles will not make the liquid transport to other parts of the absorbent structure as much. Furthermore, since the superabsorbent has a lower absorption capacity, this scattering function will remain even after a longer time. The superabsorbent particles will also not swell so much and the risk of the formation of lumps of swollen superabsorbent will decrease. A higher concentration of superabsorbent is allowed and more superabsorbent particles smaller in size in the swollen state can be contained in the same volume as fewer conventional superabsorbent particles which are larger in the swollen state. This also contributes to less clumping. Thus, a higher concentration of partially neutralized superabsorbent can be used in the absorbent structure, leading to an absorbent structure with a high total absorbent capacity and high spreading ability while retaining comfort after wetting.

The following are examples which show that the partially neutralized superabsorbent material according to the invention absorbs more slowly and absorbs less liquid than conventional superabsorbent material.

DESCRIPTION OF EXAMPLE 1

The following examples are intended to illustrate that the partially neutralized superabsorbents used in the structure of the invention absorb less fluid and slower than conventional superabsorbents. The experiments were done by dip absorption, which is intended to determine the absorption capacity of superabsorbents.

Equipment used

- Polyester gauge, mesh size 59 pm

- Welding

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- Test fluid, see below

- Weight, accuracy 0.0001 g

test fluid

Synthetic urine according to the following recipe:

Concentration

<td>Magnesium sulfate (MgSO₄)</td><td>0.66 g / l</td>

<td>Potassium chloride (KC1)</td><td>4.47 g / l</td>

<td>Sodium Chloride (NaCl)</td><td>7.60 g</td>

<td>Urea (urea) (NH₂CON₂)</td><td>18.00 g / l</td>

<td>Potassium dihydrogen phosphate (KH₂PO₄)</td><td>3.54 g / l</td>

<td>Sodium Hydrogen Phosphate (Na₂HPO₄)</td><td>0.745 g / l</td>

<td>Triton X-100 0.1%</td><td>1.00 g / l</td>

<td>Deionized water added</td><td></td>

New cook (color) 10%

0.4 g / l

Method:

- Net was cut to 7x12 cm and welded to the edges of bags.

- The bags were noticed.

- The bags (P) were weighed, accuracy 0.0001 g.

0.19-0.21 g superabsorbent (S) was weighed, accuracy 0.0001 g.

The superabsorbents were stirred.

- The bags were welded together. The bags were checked.

- The superabsorbents were evenly distributed in the bag and then carefully soaked in the test liquid.

- The bags are closed one at a time, so that the absorption time is exactly 15 seconds.

The same accuracy applies for the total absorption time up to 5 minutes, but not for 30 and 60 minutes.

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- The bags were picked up after 15 seconds and they hung and dipped for 2 minutes. The bags were hung in a home so that the bottom of the bag without welding was down.

See Fig. 1, where the bag 1 hangs in a ring 2 with three welded edges 3 and one welded edge 4 is downwards.

- Any drops were carefully wiped off.

- The bags were weighed and A &lt;i5_S), i.e., the weight of the bag after 15 seconds, accuracy of 0.0001 g.

- The bags were soaked, picked up, dropped off after total absorption times 30 sec, 45 sec, 1, 2, 5, 30 and 60 minutes to give Aqos), A _m), A &lt;_{2 m)} A &lt;_{5 m)},

A (30 m), A (60 m) ·

- The test fluid was changed after each complete test.

Calculation and indication of results = Weighted sample after absorption, gi = 15 s, 30 s, 45 s, 1 m, 2 m, 5 m, 30 m, 60 m

P = Weight empty bag, g

S = Weight superabsorbent, g

D₍i) = Absorption of sample, g / g

K = Correction for bag absorption

K = 1.6 for i = 15 s, 30 s, 45 s, 1, 2, 5, 30 and 60 min

D (i) = Affi - S - (PxK)

S

The results are collected in Table I, where IM 7110 is the partially neutralized superabsorbent and IM 7100 is the conventional superabsorbent. The results show that the absorption is lower at all times for the partially neutralized superabsorbent IM 7110, compared to the conventional superabsorbent. The results are also shown in Fig. 2 where the absorption D, is plotted against time. The curve for the partial

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513 374 neutralized superabsorbent is always below that of the conventional superabsorbent.

Table 1

<td></td><td colspan="2">Absorption (g / g)</td>

<td>TIME</td><td>IM7110</td><td>IM 7100</td>

<td>15 sec</td><td> 2,4</td><td> 8,0</td>

<td>30 sec</td><td> 18,3</td><td> 22,9</td>

<td>45 sec</td><td> 25,9</td><td> 32,9</td>

<td>1 minute</td><td> 28,4</td><td> 36,9</td>

<td>2 min</td><td> 29,6</td><td> 39,3</td>

<td>5 minutes</td><td> 30,9</td><td> 40,3</td>

<td>30 min</td><td> 32,0</td><td> 40,5</td>

<td>60 minutes</td><td> 32,8</td><td> 40,1</td>

AU use of products that are applied to skin can lead to undesirable side effects. These can occur due to occlusion, moisture, mechanical, microbial and enzymatic factors and can cause side effects such as skin irritations, primary or secondary skin infections and unwanted odors. A pH increase is a normal event when using absorbent products against the skin. However, several undesirable side effects can occur as a result of or in connection with a pH increase. Examples of such undesirable side effects are irritant contact dermatitis, which is associated with the skin's surface pH.

Another example of unwanted side effects is that some bacteria such as Proteus can metabolize substances in urine and other body fluids and give rise to smelly substances such as ammonia and amines, which also causes an increase in pH. At high pH, ​​the equilibrium of many odorous substances is shifted in such a way that more volatile components are formed, and therefore they smell more than at low pH.

The growth of microorganisms is also favored by an environment such as in an absorbent article where there is access to, among other things, moisture, nutrition and heat. High bacterial numbers make up

513 374 ίο a risk of infection. Furthermore, a high bacterial presence represents an increased risk of the appearance of unpleasant odors caused by various substances that are formed during biological or chemical degradation of constituents in body fluids, such as urine or menses. Microorganisms have an activity that is highly pH dependent and decreases with decreasing pH.

When a partially neutralized superabsorbent material is used in the absorbent structure of the invention, the pH is lowered. Thus, the above-mentioned undesirable side effects decrease in an absorbent structure according to the invention.

Partially neutralized superabsorbent material is used in absorbent articles described in Swedish patent application SE 9702298-2. A lowered pH is obtained by the absorbent structure of the product comprising a pH-controlling substance in the form of a partially neutralized superabsorbent material. It has been found that if the pH of the absorbent product, after wetting, is in the range of 3.5 - 4.9, a noticeable growth inhibitory effect on undesirable strains of microorganisms and the occurrence of undesirable side effects which may arise from the use of the output, decreases.

Examples of the relationship between the degree of neutralization and the pH of the superabsorbent material are given below. This information was obtained from application SE 9702298-2.

<td colspan="2">Neutralization%</td><td>pH</td>

<td> 25</td><td> 18</td><td> 4,0</td>

<td></td><td> 25</td><td> 4,3</td>

<td></td><td> 30</td><td> 4,5</td>

<td></td><td> 35</td><td> 4,7</td>

<td></td><td> 45</td><td> 5,0</td>

<td> 30</td><td> 60</td><td> 5,5</td>

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The degree of neutralization of the superabsorbent material of the invention is between 20 and 50%.

A further advantage of the invention is thus to avoid the appearance of, for example, bad odor and skin disorders when using an absorbent product against skin. The growth inhibitory effect is based on the fact that many microorganisms have an activity which is strongly pH dependent and decreases with decreasing pH, which is why lowering the pH leads to a reduced activity of most microorganisms. Enzymes such as lipases and proteases have an activity that is highly pH dependent and decreases with decreasing pH, which is why lowering the pH also leads to a decrease in enzyme activity and thus a decrease in negative skin effect.

The following examples illustrate the effect in absorbent articles having an absorbent body comprising partially neutralized superabsorbent material. Comparison is made with conventional materials of the corresponding type.

An absorbent body containing absorbent material and liquid is by nature a heterogeneous system from a pH point of view. The system can contain superabsorbent materials, fibers, and several ionic liquids. In order to obtain reprocessable pH values, measurements must be taken at several places in the sample body and the mean calculated.

DESCRIPTION OF EXAMPLES 2, 3, 4 and 5:

Test fluid:

Sterile synthetic urine to which growth medium has been added for microorganisms. The synthetic urine contains mono- and divalent cat and anions as well as urea and has been prepared according to information in Geigy, Scientific Tables, vol 2, 8th ed. 1981 s53.

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The growth medium for microorganisms is based on data on Hook and FSA media for enterobacteria. The pH of this mixture is 6.6.

METHODS:

Method 1, manufacture of absorption bodies for testing

Absorption bodies were manufactured using a slightly modified test body former according to SCAN C 33:80. Fluff pulp and superabsorbent material of the desired type were weighed, and an even mixture of fluff pulp and superabsorbent material was then fed into an air stream with a vacuum of about 85 mbar and through a tube of 5 cm diameter and provided with a metal mesh at the bottom of which is a thin tissue placed. The mixture of fluff pulp and superabsorbent material was thereby collected on the tissue of the metal mesh and then constituted the absorption body. The absorbent body was then weighed and compressed to a bulk of 6-12 cm / g. A number of absorption bodies named Sample 1 and Sample 2 of different composition as below were prepared. Sample 1 contains superabsorbents IM 7100, i.e. conventional superabsorbents, and sample 2 contains partially neutralized superabsorbents IM 7110.

The absorption bodies contain chemical cellulose pulp named Korsnäs EA. The total weight of the absorbent body is 0.98 g.

Weight superabsorbent material: 0.39 grams.

Weight of chemical cellulose pulp: 0.59 grams.

Method 2, pH measurement in absorption body.

An absorbent body with a diameter of about 50 mm was made according to method 1. 14 ml of test liquid was added to an absorption body, sample 1, and 11 ml of test liquid to an absorption body sample 2, after which the absorption body was allowed to swell for 30 minutes. (Different volumes of liquid were added as the superabsorbents absorb different very liquid.)

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Thereafter, the pH was measured in the absorption body by means of a surface electrode, Flat-bottomed Metrohm pH meter, Beckman 012 or 072. Parallel measurements were performed on at least two different absorption bodies. The pH was measured at 10 points on each absorption body and the mean was calculated.

Method 3, Measurement of bacterial inhibition in absorption bodies.

Bacterial suspensions of Escherichia coli (Ec), Proteus miråbilis (Pm), Enterococcus faecalis (Ef) were grown in nutrient broth (Nutrient Broth Oxoid CMI) overnight at a temperature of 30 ⁰ C. The seed cultures were diluted and bacterial levels were calculated. The cultures were mixed in different proportions, so that the final mixing culture held about 10⁴ organisms per ml of synthetic urine. 10 ml of the synthetic urine was added to a sterile sputum jar 70.5 x 52 mm, volume 100 ml, and the absorbent body was placed upside down in the jar and allowed to suck liquid for 5 minutes, after which the jar was inverted and incubated at 35 ° C in respective 0 , 6 and 12 hours, after which the bacterial value in the absorption body was determined. As a nutritional medium, TGE agar was used for measuring total bacteria and Drigalski agar for specific measurement of Escherichia coli and Proteus miråbilis and Slanetz Bartleyagar for specific measurement of Enterococcus faecalis. The results are reported in the following tables.

TEST RESULT:

Example 2

Table 2 shows that there is good inhibition of the growth of Esherichia coli in Sample 2, which consists of an absorption body containing partially neutralized superabsorbents, IM 7110.

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Table 2

<td>Esherichia coli</td><td>0 hours</td><td>6 hours</td><td>12 hours</td>

<td>Sample 1</td><td> 3,5</td><td> 7,3</td><td> 8,9</td>

<td>Sample 2</td><td> 3,5</td><td> 3,7</td><td> 3,3</td>

Example 3

From Table 3, it appears that there is good inhibition of growth of Proteus miråbilis in Sample 2, which consists of an absorption body containing partially neutralized superabsorbents, IM 7110.

Table 3

<td>Proteus miråbilis</td><td>0 hours</td><td>6 hours</td><td>12 hours</td>

<td>Sample 1</td><td> 3,2</td><td> 6,3</td><td> 9</td>

<td>Sample 2</td><td> 3,2</td><td> &lt;2</td><td> &lt;2</td>

Example 4

Table 4 shows that there is good inhibition of the growth of Enterococcus faecalis in Sample 2 consisting of an absorption body containing partially neutralized superabsorbents, IM 7110.

Table 4

<td>Enterococcus faecalis</td><td>0 hours</td><td>6 hours</td><td>12 hours</td>

<td>Sample 1</td><td> 3,4</td><td> 6,3</td><td> 7,6</td>

<td>Sample 2</td><td> 3,4</td><td> 3,3</td><td> 3,4</td>

The measurements in Examples 2-4 were performed according to Method 3.

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Thus, from Examples 2-4 it can be seen that there is good inhibition of growth of microorganisms when using a partially neutralized superabsorbent in an absorption body.

Example 5

Table 5 shows that the pH of an absorbent body of Sample 1, with conventional superabsorbent, has a higher pH, above 6 and up to 8.7 after 12 hours. In Sample 2, with partially neutralized superabsorbent, a lower pH of 4.6 is obtained and thus has a value suitable for inhibiting the growth of microorganisms.

Table 5

<td>PH</td><td>0 hours</td><td>6 hours</td><td>12 hours</td>

<td>Sample 1</td><td> 6,1</td><td> 6,2</td><td> 8,7</td>

<td>Sample 2</td><td> 4,6</td><td> 4,6</td><td> 4,6</td>

The measurements were carried out according to Method 2.

The invention thus relates to an absorbent structure in absorbent articles such as diapers, diapers, incontinence covers, sanitary napkins, pantyhose or the like, which structure comprises at least 40% by weight of superabsorbent material, based on the total weight of the absorbent structure in the dry state or regions of the superabsorbent. the material is distributed, the superabsorbent having a degree of neutralization which is between 20 and 50%. A preferred degree of neutralization is between 25 and 35%. At neutralization rates between 20 and 50% or 25 and 35%, pH is obtained which is advantageous for counteracting, for example, the growth of microorganisms and undesirable side effects are reduced in this way. This also allows for the use of the product for a longer period, both because of the lowering of the pH and the higher absorption capacity. This is a major advantage of the absorbent structure as well as the advantage of the slower and lower total absorption of the individual superabsorbent particles, which reduces the risk of gel blocking and lumping.

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The content of superabsorbent material may be between 40 and 50% by weight, based on the total weight of the absorbent structure in the dry state. However, the proportion of superabsorbent can be higher, for example up to 90% by weight. The absorbent structure may also consist solely of superabsorbent.

The stated proportion of superabsorbent material is primarily based on the total weight of the absorbent structure in the dry state or regions where the superabsorbent material is distributed.

Mainly, partially neutralized superabsorbent material is used in the absorbent structure of the invention. But it is also possible to have conventional superabsorbent material. Then, for example, the partially neutralized superabsorbent may be located in the hydrogen region, while the conventional superabsorbent may be located outside the hydrogen region. The advantage of having the superabsorbent material with the lowest degree of neutralization located to the wetting region of the product, ie to the branch area of ​​the article, as well as conventional superabsorbent material located to the end portions of the article, is that the liquid in such a structure exhibits an increased possibility of spreading from the hydrogen region to the end portions of the article. In this way, it is possible to increase the utilization rate of the total absorbent capacity of the absorbent structure, and further reduce the risk of gel blocking in the hydrogen region.

Other examples of superabsorbent distribution are that the partially neutralized superabsorbent is placed in a first zone closer to the user while the conventional superabsorbent is located to a second zone, the second zone being located below the first zone as directed by the user of the absorbent article. Hereby, the same advantages as mentioned above are obtained by spreading the liquid from the zone of the lowest degree of neutralization where liquid will first be received, to the zone of conventional superabsorbent material.

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The utilization rate can be increased and the risk of gel blocking in the layer closer to the user is reduced.

A further example is that the partially neutralized superabsorbent is applied to a layer at the bottom of the structure, which can act as a liquid spreading layer.

The concentration of the partially neutralized superabsorbent material in the examples mentioned above should then be at least 40% by weight in the areas where the partially neutralized superabsorbent material is located.

However, the preferred embodiment contains only the partially neutralized superabsorbent material, in order to obtain the lowered pH which is sought to reduce the undesirable side effects.

Since partially neutralized superabsorbent can be used at a high concentration, it can advantageously be used in a thin absorbent structure. A thin absorbent structure can be obtained with dry-formed, compressed chemitermomechanical mass CTMP, chemical mass CP or the like. A thin product is interesting from the point of view that it is discreet and comfortable.

In a preferred embodiment of the invention, in addition to the partially neutralized superabsorbent, the absorbent structure contains dry, compressed CTMP pulp, CP pulp or the like. This absorbent structure mats in a conventional manner and then is highly compressed. Thus, a very thin absorbent structure is obtained. In this case, partially neutralized superabsorbent is involved in the nucleus. For example, the superabsorbent may be homogeneously mixed with the cellulose fibers in a so-called mixed layer, or placed between two cellulose-based layers. Also, as in the structure described above, the proportion of partially neutralized superabsorbent here will be at least 40% by weight based on the total weight of the absorbent structure in the dry state or regions where the

513 374 superabsorbent material is distributed. The degree of neutralization is between 20 and 50% and preferably between 25 and 35%.

By using dry shaped, compressed CTMP pulp, CP pulp or the like in the absorbent structure, a thin product is obtained which is discrete to support. At the same time, the unwanted side effects such as bad odor and skin irritation are avoided, as described above. Also, the disadvantages mentioned above such as gel blocking and lump formation are avoided and a high absorption capacity is obtained.

Characteristic of the compressed structure according to the invention is that the core is thin before wetting and swells and distributes fluid momentarily upon wetting. By using dry-formed, compressed pulp in the absorbent structure, a structure as thin as 1 to 3 mm can be obtained. Even as thin cores as 0.5 mm can be obtained and can then be used in eg panty protection. For bamboo diapers a higher absorbent capacity is needed, and here thicknesses of up to 8 mm may be suitable. Preferred thicknesses are 1 to 8 mm and 1 to 3 mm, respectively.

The comfort is maintained despite the high concentration of superabsorbent, and this is achieved by the partially neutralized superabsorbent absorbing more slowly and having a lower absorption capacity.

The invention also relates to absorbent articles, such as diapers, diapers, incontinence covers, sanitary napkins, panties or the like, comprising an upper liquid-impervious layer, a lower liquid-impervious barrier layer, and an interposed absorbent structure, the absorbent structure of which is described above.

In absorbent articles, an inlet / transport layer is usually also included between the upper liquid permeable surface layer and the absorbent structure. An inlet / transport layer has an open and airy structure and has the task of quickly receiving a given amount of liquid and must quickly pass the liquid on to it.

513 374 absorbent structure. The inlet / transport layer may, for example, be a nonwoven material which can be made by trough-air bonding and carding or needling of synthetic fibers, such as polyester, polypropylene or mixtures thereof. Such inlet / transport layers as described above, and which mainly consist of synthetic, relatively hydrophobic fibers, are not included in what is meant in this application by the absorbent structure. In contrast, an absorbent article according to the invention may comprise such an inlet / transport layer.

A preferred embodiment of the article is that it is an incontinence or feminine product.

By the term "inclusive" we mean inclusive, but not limiting.

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