KR100331343B1 - Crosslinked powder polymer capable of absorbing aqueous and body fluids, preparation method and use thereof - Google Patents

Abstract

The present invention relates to a water-swellable crosslinked powder polymer having a high absorption capacity against an aqueous liquid, in particular a body fluid under load, wherein the polymer comprises: a) 50 mol%, an acid-atom-containing monomer having at least neutralized 55-99.9% by weight, b) 0-40% by weight of monomers copolymerizable with a), c) 0.1-5.0% by weight of one or more crosslinkers, and d) 0-30% by weight of a water-soluble polymer.

The salt of a) comprises Li ⁺ , Na ⁺ , preferably K ⁺ , Cs ⁺ , Rb ⁺ and primary, secondary, and tertiary methyl ammonium ions, alone or in combination, as cations. The polymer is prepared by adding a carbon dioxide-based blowing agent to the monomer, polymerizing, drying the polymer and heating it to 100 to 300 ° C. together with one compound or several compounds that are reactive towards the surface-crosslinking agent. Prepared. These polymers are suitable as components of hygiene articles and bandages that absorb body fluids, components of diapers, sanitary napkins, and incontinence articles, soil improvers, artificial soils for plant breeding, and packaging materials.

Description

Crosslinked powder polymers capable of absorbing aqueous and body fluids, methods for their preparation and uses

The present invention relates to a crosslinked powder polymer that absorbs aqueous liquids and blood (superabsorbers) and has improved properties for absorption rate, swellability and aqueous liquid retention capacity under high loads. The present invention also relates to a method for producing the polymer and to the use of the polymer in absorbent hygiene products such as diapers, adult incontinence materials, feminine hygiene products, and bandages.

Superabsorbents are water-insoluble crosslinked polymers capable of absorbing large amounts of body fluids and aqueous solutions, such as urine or blood, and retaining the absorbed liquid under a certain pressure or load as the hydrogel forms and swells. Because of these absorption properties, the polymers are mainly used in hygiene products such as diapers and sanitary napkins.

Initially, it was important to have a very high swelling performance (also called free swelling performance) in contact with liquids in the development of superabsorbents, but since the stability of the swollen gel as well as the amount of liquid absorbed was found to be an important factor. . However, as described in US Review No. 32,649, the absorbency, also referred to as swelling or free swelling performance, and the gel strength of the crosslinked polymers exhibit contrasting properties. The fact that the water absorption and the gel strength are in contrast to each other means that the polymer having particularly high water absorption has poor swelling gel strength, which deforms the gel under pressure (eg, weight load) and also inhibits liquid dispersion and absorption. The invention described in U.S. Review No. 32,649 discloses that when the superabsorbent material is used in a diaper structure, it balances the absorbent performance (gel volume) and gel strength to maintain dryness, liquid transport and liquid absorption of the skin and diaper. The purpose. In this connection, not only the performance of the polymer holding the liquid under pressure after swelling first occurs, but also the pressure at the same time, i.e. during liquid absorption (actually when the child or adult is sitting or lying on the sanitary It is important to note that liquid is absorbed even when shear forces are applied by movement). EP 0 339 461 refers to this particular absorption characteristic as absorbency under load.

One way to satisfy the tendency to reduce the size and thickness of hygiene products for aesthetic and environmental reasons (reducing the amount of waste at landfills) is to reduce the amount of fluff pulp, which is a large part of the diaper, while also absorbing superabsorbent content. To increase. For this reason, superabsorbents replace the additional functions for liquid absorption and liquid transport, which in the past have been performed by fluffy pulp, which has not been able to perform satisfactorily with conventional superabsorbents.

This applies in particular when the proportion of superabsorbents in the absorbent region of the hygiene article is increased to 40 to 60% by weight or more. Because of the poor absorption rate of the superabsorbent in the case of several mictions, the so-called "leakage" is caused by the liquid transport and the blocking of the liquid dispersion under a certain pressure, ie the liquid is no longer held by the sanitary article. Not absorbed, the diaper surface becomes wet, resulting in moist skin.

In order to provide superabsorbent polymers with characteristic properties such as high absorption performance, high gel strength and high absorbency under load, it is necessary to continuously surface the polymer resin.

For example, US Pat. No. 4 043 952 recommends a polyvalent metal compound that improves water dispersibility, and US Pat. No. 4 051 086 suggests the use of glyoxal to improve the rate of absorption. DE-OS 27 40 169 discloses a process for the preparation of potassium acrylate and ammonium acrylate-containing polymeric absorbents treated with polyols, which are used in medical and diaper and other hygiene products in the form of powders and sheets. . The secondary treatment method of the resin using a crosslinking agent comprising a divalent functional group or a polyvalent functional group capable of reacting with a carboxyl group, a carboxylate group and the like contained in the polymer is EP 0 083 022 (method for improving water dispersibility and water absorption). DE-OS 33 31 644 (how to improve resistance to salt solutions at high water absorption rates), DE-OS 35 07 775 (how to increase the resistance of salts with good liquid absorption and gel strength), DE-OS 35 23 617 (how to improve fluidity and prevent flocculation), DE-OS 36 28 482 (how to improve water absorption during repeated use), and EP 0 349 240 (gel strength and suction as well as balance between absorption and absorption rate) How to achieve a balance between In these cases, the powder is directly mixed with the components or optionally dispersed in an inert solvent using a small amount of water and solvent; Or the polymer containing 10 to 40% by weight of water is dispersed in a hydrophilic or hydrophobic solvent and mixed with the crosslinker continuously or simultaneously. Suitable crosslinkers include polyglycidyl ethers, halo epoxy compounds, polyols, polyamines, or polyisocyanates. In addition, DE-OS 33 14 019, EP 0 317 106, and DE-OS 37 37 196 are multifunctional aziridine compounds, alkyl-di- (tri) -halides, and oil-soluble polyepoxys. Compounds are described. DE-OS 35 03 458 (invention to obtain polymers with high gel strength, high absorption rate and good absorption capacity in non-viscosity gels) in the presence of inert inorganic powder materials such as SiO ₂ without the use of organic solvents It is described below that the application of the crosslinking agent is carried out on the polymer resin. According to DE-PS 40 20 780, the absorbency under load is improved by crosslinking the surface of the polymer resin with 0.1 to 5% by weight of alkylene carbonate.

All the above methods have a common point in that the temperature treatment process of the resin is continuously performed.

Superabsorbents obtained according to the prior art have a high swellability under a load of 20 g / cm 2 as disclosed in DE-PS 40 20 780, where 28 to 34 g of 0.9% sodium chloride solution per 1 g of superabsorbent is absorbed (AUL ). It is also reported that products made according to this patent have a high initial liquid absorption rate under load, so that 80% of the total absorption capacity is achieved after only 15 minutes.

However, it has been found that the absorption rate of the polymer resin obtainable by the secondary treatment as known in the art when the liquid absorption takes place under a simultaneously acting load is relatively high. However, in the case of swelling without load, the absorbency must be improved.

Rapid absorption of liquids under loadless swelling is very important when using absorbent resins in hygiene articles, for example, baby diapers and adult pads are not always subjected to weight loads, and in this case a large amount to prevent leakage This is because the liquid must be absorbed rapidly.

In addition, absorbent resins known in the art have the disadvantage that the swelling performance is substantially reduced under a load of 20 g / cm 2 or more. Thus, in known polymers having an AUL (absorbency under load) of 30 g / g under a load of 20 g / cm 2, the AUL is reduced to 15 g / g under a load of 40 g / cm 2 and 9 g / under a load of 60 g / cm 2. reduced to g. The reduced absorbent performance under high pressure has a particularly negative effect on the new diaper structure where the proportion of superabsorbent material is increased, where the absorbent resin transports the liquid to distant storage areas. In this case it deforms under high pressure due to insufficient gel stability and also forms a soft gel that worsens the liquid transport due to so-called "gel blocking".

Accordingly, it is an object of the present invention to provide superabsorbent polymers having improved absorption rates and high retention, and particularly high absorbency under increased loads.

This object is achieved by water swellable crosslinked powdered polymers which absorb water, aqueous liquids, in particular body fluids,

The polymer consists of the following a) to d), wherein the total sum of a) to d) is 100% by weight, preferably at least 12 g of 0.9% NaCl solution per gram of polymer at a load of 60 g / cm 2. Preferably has an absorption capacity to absorb more than 16 g:

a) 55 to 99.9 weight percent of a polymerized unsaturated, polymerizable acid group-containing monomer present as a neutralized salt of at least 50 mol%,

b) 0-40% by weight of polymerized unsaturated monomer copolymerizable with a),

c) 0.1 to 5.0% by weight of crosslinking agent,

d) 0-30 wt% of water-soluble polymers

Very surprisingly, when a carbon dioxide-based blowing agent is added to the monomer solution prior to the polymerization step during the preparation of the polymer product, the cation is lithium, sodium, and preferably potassium, rubidium, cesium, ammonium, monomethyl ammonium, dimethyl ammonium, or The absorption rate of superabsorbent polymers having neutralized acid groups selected from the group consisting of trimethyl ammonium is greatly improved. At the same time, the absorbency of the superabsorbent of the present invention is improved at high loads because the particulate absorbent resin is treated with a reactive multifunctional auxiliary crosslinker and heated to 120-300 ° C.

U.S. Patent No. 4 529 739 describes the preparation of an absorbent starting material with a hydrophobic polymer in latex form by a saponification process in which carbonate is added as a blowing agent.

U.S. Patent No. 5 118 719 describes a method for producing a superabsorbent polymer with improved rate of water absorption using a carbonate-containing blowing agent that forms a hydrogel having a microcell structure by releasing carbon dioxide. As disclosed in the examples of US Pat. No. 5,118,719, the absorption rate is improved, but the absorption performance is reduced. Absorbent resins prepared by the method disclosed in US Pat. No. 5,118,719 have absorbency under load (AUL) significantly worse than products known in the art, such as those of DE-PS 40 20 780. The known prior art method has a high water absorbency under a load of 20 g / cm 2, but no water absorbent resin has been obtained in which the water absorption rate is improved upon no-load swelling. Thus, the above-mentioned prior art does not mention a method of achieving a suitable combination of improved absorption rate under both no-load absorption and absorption under load and improved absorption capacity under high pressure.

When using hydrogels having a microcell structure produced by using blowing agents, improved water absorbing resins can be obtained, and these resins can be subjected to surface-crosslinking, for example, according to the method described in DE-PS 40 20 780. It was found that it can. In addition, the cations of lithium, sodium, preferably potassium, rubidium, cesium and ammonium, monomethyl ammonium, dimethyl ammonium, or trimethyl ammonium, present in the salts produced by the neutralization reaction of the acid group-containing monomers are absorbed and absorbed. It was found to have a significant effect on speed. It has been found that the absorption capacity can be improved and the absorption rate can be improved to a considerable extent under load.

Preferred cations are potassium ions and ammonium ions.

Water-absorbent resins that can be used for surface crosslinking treatments are prepared by polymerizing 55 to 99.9 weight percent of monomers having acidic groups such as acrylic acid, methacrylic acid, 2-acrylamido-2-methylpropane sulfonic acid, or mixtures of these monomers. Obtained; The acid groups are present in a state in which at least 50 mol% is neutralized. Particular preference is given to resins composed of crosslinked acrylic acid or methacrylic acid neutralized by about 50 to 80 mole%.

The neutralization reaction of the acid groups in the aqueous monomer solution is carried out with bases, yekke alkaline solutions, carbonates or amines according to known methods. In addition to caustic soda solutions, preferred neutralizing agents are, in particular, potassium alkaline liquid and ammonia. In addition, suitable monomers for the preparation of the water absorbent resin include 0 to 40% by weight of acrylamide, methacrylamide, hydroxyethyl acrylate, dimethylaminoalkyl (meth) -acrylate, dimethyl aminopropyl acrylamide, or acrylamido. Propyl trimethyl ammonium chloride. If the proportion of these monomers exceeds 40%, the swelling performance of the resin is weakened.

One or more functional groups reactive with two or more ethylenically unsaturated double bonds or one ethylenically unsaturated double bond or an acid group, or any compound having several functional groups reactive with an acid group can be used as the crosslinking agent. Examples thereof include acrylates and methacrylates of polyols, such as butanediol diacrylate, hexanediol dimethacrylate, polyglycol diacrylate, trimethylolpropane triacrylate, or allyl acrylate, diallyl acrylamide, tri Allyl amine, diallyl ether, methylene bisacrylamide, or N-methylol acrylamide, and also polyglycidyl ethers such as ethylene glycol diglycidyl ether and glycerol polyglycidyl ether and / or polyols such as Glycerol, trimethylol propane and / or polyalkylene glycols such as polyethylene glycol 200 to 600. In addition, polyamines can be used.

Polyvinyl alcohol, polyvinyl pyrrolidone, starch or starch derivatives, polyglycols, or polyacrylic acid, all or partly saponified (0 to 30% by weight), may be included in the water absorbent resin as a water soluble polymer. If the polymer is water soluble, the molecular weight of the polymer is not critical. Preferred water-soluble polymers are starch or polyvinyl alcohol or mixtures of these polymers. In particular, when starch and / or polyvinyl alcohol is present as the water soluble polymer, the content of the water soluble polymer in the water absorbent resin is preferably about 1 to 5% by weight. The water soluble polymer may be present as a graft polymer having an acid group containing polymer.

In addition to the resins obtained by crosslinking polymerization of partially neutralized acrylic acid, it is preferred to use those which further comprise graft polymerized starch or polyvinyl alcohol moieties.

The preparation of the water absorbent resin of the present invention is carried out according to a known method. This method can be carried out by an aqueous solvent polymerization reaction (gel process) or by an inverse emulsion / suspension polymerization method.

According to the invention, carbon dioxide-based or gaseous or solid carbon dioxide-based blowing agents as carbonates must be dissolved or dispersed in the monomer solution or dispersion. An amount of 0.1 to 5.0% by weight relative to the anhydrous polymer material may be used as the carbonate, such as sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, magnesium carbonate, calcium carbonate, or a mixture of these materials. When solid carbon dioxide (dry ice) is used, the monomer solution or dispersion can be cooled to -10 ° C to 30 ° C, preferably 0 to 10 ° C, and oxygen can be removed at the same time.

In the surface crosslinking treatment, there is no particular limitation on the particle shape of the absorbent value used. The polymer may be present in the form of small beads obtained by reverse suspension polymerization, or in the form of irregularly shaped particles produced by drying and pulverizing the material obtained by solvent polymerization. The hydrogel is dried at 80-200 ° C., in particular at 100-180 ° C. and preferably at 120-150 ° C .. Generally, the particle size is 20 to 3,000 mu m, preferably 50 to 1,000 mu m.

In the surface crosslinking treatment, a known secondary crosslinking agent mainly composed of two or more functional compounds reactive with an acid group, especially a carboxyl group, and a water absorbent resin can be mixed. The water absorbent resin may be mixed with the secondary crosslinker directly in an aqueous solution or a mixed solution of water and alcohol. The content of the secondary crosslinker is 0.01 to 10% by weight, preferably 0.01 to 4.0% by weight, most preferably 0.01 to 2.0% by weight relative to the water absorbent resin. In addition, other secondary crosslinker mixtures may also be used. The amount of alcohol is determined by the solubility of the secondary crosslinker and is kept as low as possible for technical reasons such as explosion protection. Suitable alcohols are methanol, ethanol, butanol, or butyl glycol and mixtures of these alcohols. Preferred solvents are water used in amounts of 0.3 to 5.0% by weight relative to the resin. It is also possible to use secondary crosslinkers derived from powder mixtures using inorganic carrier materials such as SiO ₂ .

Two or more compounds of the surface crosslinker that are reactive with acid groups are preferably polyols (eg glycerol) and / or polyalkylene glycols (eg polyethylene glycol) and / or polyamines (eg triethanolamine). According to DE-PS 40 20 780 it is particularly preferred to use alkylene carbonates as surface crosslinkers.

In order to obtain the desired properties, the crosslinking agent must be evenly distributed in the resin powder. To this end it was mixed using a suitable mixer such as a fluid bed mixer, paddle mixer, milling roll, or a two-worm-mixer.

It is also possible to treat the water absorbent resin in one production step when producing the polymerizable resin. For this purpose, a particularly suitable method is the reverse suspension polymerization method. This heat treatment method is carried out at 100 to 300 ° C, preferably 120 to 250 ° C after the addition of the surface-crosslinking agent. This temperature depends on the residence time and the type of reaction reagent. At 150 ° C., heat treatment must be performed for several hours, while at 250 ° C., heat treatment for only a few minutes, such as 0.5 to 5 minutes, is sufficient to obtain the desired properties. The heat treatment can be carried out in a conventional dryer or oven, such as a rotary furnace, fluid bed dryer, paddle dryer, disk dryer, or infrared dryer.

The polymers of the present invention can be produced on a large scale by continuous or discontinuous processes. The polymer of this invention can be used for various uses. When used as an absorbent material in sanitary napkins and diapers or as bandages, they have the property of rapidly absorbing large amounts of menstrual blood, urine or gaseous body fluids. Its absorption capacity and absorption rate were far superior to conventional products. The polymer of the present invention is easy to use because it absorbs liquid under high pressure load and retains the absorbed liquid. The polymers of the present invention are particularly suitable for use at higher concentrations-relative to hydrophilic fibrous materials, such as downy pulp-than polymers used to date. In use, the ratio of the absorbent polymer to the combined content of the absorbent polymer and the down may exceed 35% by weight; It may be present in an amount of 15-100% by weight, preferably 30-70% by weight. The polymer of the present invention is particularly excellent in terms of fluid distribution in the polymer containing layer immediately after liquid absorption.

In addition, the polymer of the present invention used as an absorbent of water and aqueous solution is useful as a current conducting cable, an optical transmission cable, a packaging material, and the polymer of the present invention is also useful as a soil improver and artificial soil for plant breeding.

Test method:

The retention capacity (TS), absorbency under load (AUL) and absorption rate / absorption rate (AV and Vortex) of the water absorbent resin were measured.

Retention capacity was measured according to the tea bag method and recorded as the average of three measurements. About 200 mg of the resin is sealed in a tea bag and soaked in 0.9% N 2 Cl-solution for 20 minutes. The teabag is then centrifuged for 5 minutes in a centrifuge (diameter: 23 cm; rpm: 1,400) and weighed. One tea bag without water-absorbent resin is used as the blank test.

Absorbency under load (AUL) is measured according to the method described in EP 0 339 461.7. The initial weight of the superabsorbent is placed in a cylinder equipped with a sieve and loaded with a piston that applies 20 g / cm 2, 40 g / cm 2 and 60 g / cm 2 pressure to the powder. The cylinder is then placed in a demand-absorbent-tester (DAT) and the superabsorbent absorbs 0.9% of NaCl-solution for 1 hour.

Absorption rate (AV) is measured according to a variant of the Absorbency Under Load (AUL) method as described in EP 0 339 461.7. In this case, the absorption of a 0.9% solution of sodium chloride is measured without loading a powder with additional weight. The amount of liquid absorbed after 15 seconds, 30 seconds, 1 minute, 3 minutes, 5 minutes, 10 minutes and 15 minutes is measured. Repeat the measurement three times.

The vortex test to determine the absorption is carried out according to the method of WO 87/03208, page 9. The initial weight of the polymer was 2.0 g; The time until the vortex disappeared was measured by starting time at which the polymer was sprayed with liquid, and measured in seconds.

Example

Comparative Example 1

According to example 4 of DE-PS 40 20 780, a mixture of sodium acrylate and acrylic acid (molar ratio 70:30), and an aqueous monomer solution composed of triallylamine as crosslinking agent are polymerized. The resulting gel was ground, dried, ground and sieved to a particle size of 90-850 μm.

The powder product is mixed with 0.2 / 0.1 / 2.0% 1,3-dioxolan-2-one / water / ethanol mixture for this powder and heated at 180 ° C. for 1 hour. The properties of this product are shown in Table 1 below.

Comparative Example 2

According to Example 4 of US Pat. No. 5,118,719, a mixture of sodium acrylate and acrylic acid (molar ratio 70:30), and an aqueous monomer solution composed of triallylamine as crosslinking agent were then polymerized, followed by addition of 0.5% basic magnesium carbonate. do. The obtained gel is ground, dried, ground and sieved (90 to 850 µm).

Example 1

Comparative Example 1 is repeated. However, as described in US Pat. No. 5,118,719, 0 5% of basic magnesium carbonate is added to the monomer solution as a blowing agent which releases CO ₂ before polymerization. The resulting powdered polymer is subjected to the same secondary treatment as in Comparative Example 1, the properties of which are shown in Table 1.

TABLE 1

week

TB = Tea Bag Test

AUL = absorbency under load

AV = absorption rate

Examples 2-8

Example 2: Potassium Acrylate

Example 3: Potassium Acrylate

Example 4: Potassium Acrylate

Example 5: Potassium acrylate

Example 6: Ammonium Acrylate

Example 7: Methyl Ammonium Acrylate

Example 8: Cesium Acrylate

And a monomer aqueous solution composed of a mixture of acrylic acid (molar ratio 70/30) and triallyl amine as crosslinking agent were polymerized under the addition of carbonate and 0-1% polyvinyl alcohol (PVA). The resulting gel was ground, dried, ground and sieved (90-850 μm). The sieved powder product was mixed with a mixture of 1,3-dioxolan-2-one or ethylene glycol diglycidyl ether (EGDE), water and ethanol and heated at 120-300 ° C. for 0.5-1 hour.

Examples 9 and 10

Example 9: Potassium Acrylate

Example 10: ammonium acrylate

The aqueous monomer solution consisting of a mixture of and acrylic acid (molar ratio is 70/30) and triallyl amine as crosslinking agent was saturated with carbon dioxide (using dry ice) while adding 0-1% polyvinyl alcohol (PVA) and then polymerized. The resulting gel was ground, dried, ground and sieved (90-850 μm). The sieved powder product was mixed with a mixture of 1,3-dioxolan-2-one and ethylene glycol diglycidyl ether (EGDE), water and ethanol, and heated to 120-300 ° C. for 0.5-1 hour. The composition, reaction conditions, and properties of the product are shown in Table 2 below.

TABLE 2

Table 2 (continued)

Comparative Example 3

Comparative Example 2 is repeated. The same molar ratio of potassium alkaline solution is used instead of caustic soda solution for neutralization. Prior to polymerization, 1.5% potassium carbonate was added to the monomer solution.

Comparative Example 4

Comparative Example 1 is repeated. Instead of caustic soda solution for neutralization, use alkaline alkaline solution in the same molar ratio. The powdery polymer thus obtained is subjected to the same secondary treatment as in Comparative Example 1.

Comparative Example 5

Comparative Example 3 is repeated. Aqueous ammonia is used in the same molar ratio instead of the potassium alkaline solution required for neutralization Prior to polymerization, 0.5% ammonium carbonate is added to the monomer solution.

Comparative Example 6

Comparative Example 4 is repeated. Aqueous ammonia is used in the same molar ratio instead of the potassium alkaline liquid required for partial neutralization. The powder product is mixed with a mixture consisting of 0.25 / 2.0 / 2.0 EGDE / water / acetone for this powder and heated at 120 ° C. for 1 hour.

table

Comparative Example 7

Prior to the secondary treatment, the polymer of Example 2 is sieved into 100-300 μm fractions and no secondary treatment is performed. Swelling rate (swelling height after 1 minute) and swelling height after 10 minutes were measured by FIRET-Test [Messrs. Lantor B V. Method; Measured according to Veenendaal / NL (see table). The test was modified in such a way that the non-woven fabric or tissue was evenly distributed and covered at the base of the measuring vessel instead of the 0.2 g superabsorbent tape (tape-hair experiment).

Example 11

Before the secondary treatment, the polymer of Example 2 is sieved into 100-300 μm fractions and then the secondary treatment as in Example 1 is carried out. The properties of this product are tested as in Comparative Example 7 (see table).

Example 12

After the second treatment, the polymer of Example 2 is sieved into 100-300 μm fractions. The properties of this product are tested in the same manner as in Comparative Example 7 (see table).

The product according to the invention obtained in Examples 11 and 12 is suitable as a component of the current conducting cable and the optical transmission cable as a sealant which prevents water permeation.

Claims (31)

a) 55 to 99.9 weight percent of a polymerized unsaturated, polymerizable acid group-containing monomer wherein at least 50 mol% is present as a neutralized salt, b) 0-40% by weight of a polymerized unsaturated monomer copolymerizable with a), c) 0.1-5.0 wt% of at least one crosslinking agent, and d) A water-swellable crosslinked powder polymer which absorbs an aqueous aqueous solution, wherein the total sum of the components a) to d), including 0-30% by weight of the water-soluble polymer, is 100% by weight, A water-swellable crosslinked powder polymer characterized by having an absorption capacity of absorbing at least 12 g of 0.9% NaCl solution per gram of polymer under a load of 60 g / cm 2. The method of claim 1, A water-swellable crosslinked powder polymer, characterized in that the polymer has an absorption capability of absorbing at least 10 g of 0.9% NaCl solution per gram of polymer within 30 seconds. The method according to claim 1 or 2 A water-swellable crosslinked powder polymer characterized by a particle size of 20 to 3,000 μm. a) 55 to 99.9 weight percent of a polymerized unsaturated, polymerizable acid group-containing monomer wherein at least 50 mol% is present as a neutralized salt, b) 0-40% by weight of a polymerized unsaturated monomer copolymerizable with a), c) 0.1-5.0 wt% of at least one crosslinking agent, and d) A water-swellable crosslinked powder polymer which absorbs an aqueous aqueous solution, wherein the total sum of a) to d) is 100% by weight, including 0-30% by weight of a water-soluble polymer, The salt of a) alone or in combination with Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Rb ⁺ and ammonium ions and primary, secondary and tertiary methyl ammonium ions as cation: carbon dioxide based blowing agent 0.1 for the polymer ˜5.0 wt.% Is added to the monomer before the polymerization reaction; The polymer is dried and one compound or several compounds, or solutions or dispersions thereof, reactive to the secondary surface-crosslinking agent is added: water-swellable crosslinking characterized by heating to 100 to 300 ° C. Powdered polymer. The method according to claim 1 or 2, The acid group-containing monomer a) is selected from the group consisting of acrylic acid, methacrylic acid, acrylamidomethylpropane sulfonic acid, and mixtures of these monomers, and monomer b) is acrylamide, methacrylamide, hydroxyalkyl acrylate, dimethyl Amino-alkyl (meth) acrylates, dimethylaminopropyl (meth) acrylamides, quaternary amines and ammonium salts of these monomers and mixtures of these monomers, crosslinking agent c) is alkylene bisacrylamide, N-methyl All acrylamide, butanediol diacrylate, hexanediol dimethacrylate, polyglycol diacrylate, trimethylolpropane triacrylate, allyl acrylate, diallyl acrylamide, triallyl amine, diallyl ether, polyglycidyl Ethers, polyols, polyalkylene glycols, and polyamines, or mixtures of these crosslinkers Is selected from the group eojin, The carbon dioxide-based blowing agent is selected from the group consisting of Na ₂ CO ₃ , K ₂ CO ₃ , (NH ₄ ) ₂ CO ₃ , MgCO ₃ , CaCO ₃ , NaHCO ₃ , KHCO ₃ , and mixtures of these carbonates: gas or solid A water-swellable crosslinked powder polymer, characterized in that it is in form of carbon dioxide. The polymer production method according to claim 1, 2 or 4, wherein in the presence of a water-soluble polymer d), a monomer a), a monomer b) copolymerizable with a) and a crosslinking agent c) are polymerized, The salt of a) is selected from the group consisting of lithium ions, sodium ions, potassium ions, cesium ions, rubidium ions, ammonium ions, primary methyl ammonium ions, secondary methyl ammonium ions, tertiary methyl ammonium ions, or mixtures of these ions Become; 0.1-5.0% by weight of carbon dioxide-based blowing agent is added to the monomers prior to the polymerization reaction for the polymer: the polymerization reaction of the obtained monomer mixture is initiated by exposure or irradiation with light under the formation of a hydrogel or by radical formation. By adding a body; The polymer obtained is dried; Adding one or several compounds, or dispersion solutions thereof, that are reactive with secondary near-surface-crosslinkers of the polymer; A method for producing a polymer, characterized by heating this to 100 to 300 ° C. The method of claim 6, A method for producing a polymer, characterized by drying the polymer at 80 to 200 ° C. The method of claim 6, A method for producing a polymer, characterized in that the polymer is dried and then ground. The method of claim 6, A method for producing a polymer, characterized by screening for polymers having a particle size of 20 to 3,000 μm as screening. The method of claim 6, A method for producing a polymer, characterized by performing near-surface-crosslinking by heating to 100 to 300 ° C. The method of claim 6, A process for producing a polymer, characterized in that the polymerization reaction is carried out in an aqueous solution. The method of claim 6, A process for producing a polymer, characterized in that the polymerization reaction is carried out in water-in-oil (w / o) -dispersion. A body fluid absorbent hygiene article comprising the polymer according to claim 1, 2 or 4 as one component. The body fluid absorbent hygiene article of claim 13, wherein the body fluid absorbent hygiene article is selected from diapers, sanitary napkins, and urinary incontinence articles. A diaper comprising 15 to 100% by weight of the polymer according to claim 1, 2 or 4 as one component based on the weight of the polymer and fluff. A current conducting cable and an optical transmission cable comprising the polymer according to claim 1, 2 or 4 as one component. A soil improving agent comprising the polymer according to claim 1, 2 or 4 as one component. The artificial soil for plant breeding containing the polymer of Claim 1, 2 or 4 as one component. The packaging material containing the polymer of Claim 1, 2 or 4 as one component. A bandage comprising the polymer according to claim 1, 2 or 4 as one component. The method according to claim 1, 2 or 4, A water-swellable crosslinked powder polymer, characterized in that the water-swellable crosslinked powder polymer absorbs body fluids. The method according to claim 1 or 2, A water-swellable crosslinked powder polymer characterized by having an absorption capability of absorbing at least 16 g of 0.9% NaCl solution per gram of polymer. The method according to claim 1 or 2, A water-swellable crosslinked powder polymer characterized by a particle size of 100 to 1000 μm. The method of claim 5, A water-swellable crosslinked powder polymer characterized in that the polyglycidyl ether is ethylene glycol diglycidyl ether and glycerol polyglycidyl ether. The method of claim 5, A water-swellable crosslinked powder polymer characterized in that the polyol is glycerol and trimethylolpropane. The method of claim 5, Water-swellable crosslinked powder polymer, characterized in that the polyalkylene glycol is polyalkylene glycol 200 to 600. The method of claim 6, A method for producing a polymer, characterized by drying the polymer at 100 to 180 ° C. The method of claim 6, A method for producing a polymer, characterized in that the polymer is dried at 120 to 150 ° C. The method of claim 6, A process for producing a polymer, characterized in that a polymer having a particle size of 50 to 1000 μm is selected as a sieving. The method of claim 15, A diaper comprising 35 to 100% by weight of a polymer as one component based on the weight of the polymer and fluff. The method of claim 15, A diaper comprising 35 to 70% by weight of a polymer as one component based on the weight of the polymer and fluff.