DE102006037983A1 - Water-absorbing polymer structure with improved permeability and absorption under pressure - Google Patents

Abstract

The present invention relates to a process for producing water-absorbing polymer structures, comprising the process steps: i) providing an untreated, water-absorbing polymer structure; ii) contacting the untreated, water-absorbing polymer structure with a salt comprising a divalent or higher valent cation of a metal and at least one organic base as anion. The invention furthermore relates to the water-absorbing polymer structures obtainable by this process, water-absorbing polymer structures, a composite comprising a water-absorbing polymer structure and a substrate, a process for producing a composite, the composite obtainable by this process, chemical products such as foams, moldings and fibers water-absorbing polymer structures or a composite, the use of water-absorbing polymer structures or a composite in chemical products and the use of a salt to treat the surface of water-absorbing polymer structures.

Description

The The present invention relates to a process for producing water-absorbing Polymeric structures, the water-absorbing by this method available Polymer structures, water-absorbing polymer structures, a composite including a water-absorbing polymer structure and a substrate, a method for producing a composite by this Method available Composite comprising chemical products such as foams, shaped bodies and fibers water-absorbing polymer structures or a composite, the use water-absorbing polymer structure or a composite in chemical Products and the use of a salt to treat the surface of water-absorbent Polymer structure.

superabsorbent are water-insoluble, crosslinked polymers that are capable of swelling and forming of hydrogels great Amounts of aqueous Liquids, especially body fluids, preferably urine or blood, and take under a certain Withhold pressure. By these characteristic properties these polymers find mainly Application in the incorporation in sanitary articles, such as Baby diapers, incontinence products or sanitary napkins.

The production of the superabsorbents is generally carried out by the radical polymerization of acid group-carrying monomers in the presence of crosslinking agents. In this case, polymers with different absorber properties can be prepared by selecting the monomer composition, the crosslinker and the polymerization conditions and the processing conditions for the hydrogel obtained after the polymerization. Further possibilities are offered by the preparation of graft polymers, for example using chemically modified starch, cellulose and polyvinyl alcohol DE-OS 26 12 846 ,

at the present commercially available Superabsorbents are essentially crosslinked polyacrylic acids or crosslinked starch-acrylic acid graft polymers, in which the carboxyl groups partially with sodium hydroxide solution or potassium hydroxide solution are neutralized.

From aesthetic establish and from environmental aspects there is an increasing tendency to sanitary articles getting smaller and thinner to design. To maintain a consistent total retention capacity of sanitary ware to ensure, This requirement can only by reducing the proportion of large-volume Fluff be met. As a result, the superabsorbent fall further Tasks regarding the transport and distribution of liquids too, posing as permeability properties to summarize.

Under permeability Superabsorbent materials are understood to have the ability to be added in the swollen state liquids to transport and distribute in three dimensions. This process runs in swollen superabsorbent gel over capillary transport through spaces between the gel particles from. A liquid transport by swollen superabsorbent particles themselves follows the laws Diffusion is a very slow process in the usage situation of the sanitary article plays no role in the distribution of the liquid. For superabsorbent materials, the a capillary transport due to lack of gel stability not can accomplish was made by embedding these materials in a fibrous matrix Separation of the particles from each other while avoiding the gel-blocking phenomenon ensured. In diaper constructions new generation is located in the absorber layer little or at all no fiber material to support of liquid transport. The superabsorbers used here must therefore be sufficient high stability in the swollen state, so that the swollen gel still one has sufficient amount of capillary space, through the liquid can be transported.

In order to obtain superabsorbent materials with high gel stability, on the one hand, the degree of crosslinking of the polymer can be increased, which inevitably results in a reduction of the swelling capacity and the retention capacity. An optimized combination of different crosslinkers and comonomers, as in DE 196 46 484 Although the permeability properties can be improved, they can not be improved to a level which, for example, permits the incorporation of a layer, which may be composed only of superabsorbers, into a diaper construction.

Farther can Methods for aftertreatment of the surface of polymer particles Improvement of superabsorbent properties are used. As a surface treatment For example, postcrosslinking of the absorbent polymer structure on the surface, contacting the surface with inorganic compounds or the post-crosslinking of the surface in the presence of inorganic Compounds known in the art.

So reveal DE 199 09 653 A1 and DE 199 09 838 A1 powdery, surface-postcrosslinked, water, aqueous or serous liquids or blood-absorbing polymers which are based on acid group-bearing monomers and which has been coated with a surface postcrosslinking agent and preferably aluminum sulfate in aqueous solution and postcrosslinked. The polymers disclosed in this prior art have advantageous absorption properties, in particular high permeability, over conventional polymers.

DE 102 49 821 A1 also describes powdery, surface postcrosslinked, high permeability, water-absorbing polymer structures obtained by surface-treating untreated, water-absorbent polymer structures with a mixture of a crosslinker and an inorganic sol, for example, silica sol.

Of the Disadvantage of the surface modification measures known from the prior art, in particular the treatment of water-absorbing polymer structures with inorganic salts or inorganic sols for the purpose of permeability enhancement However, it insists, in particular, that the observed increase in permeability often also with a significant reduction in the absorbency under Pressure is associated. This reduction in absorbency under Pressure leads often to an increased Leakage tendency of sanitary articles after the one-off and in particular multiple eating by the user.

Of the Present invention was based on the object resulting from the Overcome prior art disadvantages.

Especially The object of the present invention was to provide superabsorbents to provide, on the one hand, the transport of aqueous liquids such as urine in hygiene articles such as absorbent pads or cores, in particular for diapers, promotes high superabsorbent concentrations and so the wearing comfort to increase this hygiene article.

Farther the present invention was based on the object, a method specify, with the thus advantageous superabsorbent and a composite including these superabsorbents can be made.

Also was the object of the present invention, as possible thin hygiene products to provide a high content of water-absorbing polymer structures, which are characterized by good performance properties.

• i) Bereitstellen eines unbehandelten, wasserabsorbierenden Polymergebildes;
• ii) in Kontakt bringen des unbehandelten, wasserabsorbierenden Polymergebildes mit einem Salz umfassend ein zwei- oder höherwertiges Kation eines Metalls sowie mindestens eine organische Base als Anion, wobei das in Kontakt bringen der wasserabsorbierenden Polymergebilde mit dem Salz gegebenenfalls bei einer Temperatur in einem Bereich von 30 bis 210°C, besonders bevorzugt von 100 bis 200°C und am meisten bevorzugt in einem Bereich von 160 bis 190°C erfolgt.

A contribution to achieving the abovementioned objects is provided by a method for producing a water-absorbing polymer structure, comprising the method steps:

• i) providing an untreated, water-absorbing polymer structure;
• ii) contacting the untreated, water-absorbing polymer structure with a salt comprising a divalent or higher-valent cation of a metal and at least one organic base as anion, wherein contacting the water-absorbing polymer structures with the salt optionally at a temperature in a range of 30 to 210 ° C, more preferably from 100 to 200 ° C and most preferably in a range of 160 to 190 ° C.

• (a1) das unbehandelte, wasserabsorbierende Polymergebilde wird nicht mit einem Oxid eines Metalls, vorzugsweise nicht mit einem Oxid eines Übergangsmetalls, am meisten bevorzugt nicht mit einem Oxid des Zinks, in Kontakt gebracht;
• (a2) das unbehandelte, wasserabsorbierende Polymergebilde wird nicht mit einem Polykation, vorzugsweise nicht mit einem vorzugsweise organischen Polykation, welches vorzugsweise ein Molekulargewicht von mehr als 3.000 g/mol aufweist, am meisten bevorzugt nicht mit einem Polymer aus Diallyldimethylammoniumchlorid, in Kontakt gebracht;
• (a3) das unbehandelte, wasserabsorbierende Polymergebilde weist eine gemäß der hierin beschriebenen Testmethode bestimmte Retention von weniger als 37,5 g/g auf.

According to another embodiment of the method according to the invention, at least one, preferably at least two, and most preferably all three of the following conditions (a1) to (a3) are satisfied:

• (a1) the untreated, water-absorbing polymer structure is not contacted with an oxide of a metal, preferably not with an oxide of a transition metal, most preferably not with an oxide of the zinc;
• (a2) the untreated, water-absorbing polymer structure is not contacted with a polycation, preferably not with a preferably organic polycation, which preferably has a molecular weight greater than 3,000 g / mol, most preferably not with a polymer of diallyldimethylammonium chloride;
• (a3) The untreated, water-absorbing polymer structure has a retention of less than 37.5 g / g determined according to the test method described herein.

Quite surprisingly, but no less advantageously, it was found that the decrease in absorption under a pressure load, which often in the surface modification of water-absorbing Po lyme formation with permeability-increasing agents, can be reduced by the use of salts as permeability-increasing agents comprising a divalent or higher-valent cation of a metal as well as at least one organic base as anion.

"Untreated" in the sense of the present Invention means that the methods provided in step i), water-absorbing polymer structures not yet comprising the salt a two- or higher value Cation of a metal and at least one organic base as anion been brought into contact. The term "untreated", however, concludes not that the water-absorbing polymer structures by means of other surface modification measures, such as surface postcrosslinking, can be modified.

When in process step i) provided untreated, water-absorbing Polymeric structures are fibers, foams or particles preferred, with fibers and particles preferred and Particles are particularly preferred.

According to the invention preferred Polymer fibers are sized to be in or as yarns for textiles and can also be incorporated directly into textiles. It is preferred according to the invention, that the polymer fibers have a length in the range of 1 to 500 mm, preferably 2 to 500 mm and especially preferably 5 to 100 mm and a diameter in the range of 1 to 200 denier, preferably 3 to 100 denier and more preferably 5 own up to 60 deniers.

According to the invention preferred Polymer particles are sized to have an average particle size according to ERT 420.2-02 in the range of 10 to 3000 μm, preferably 20 to 2000 microns and more preferably 150 to 850 μm or 150 to 600 μm. It is particularly preferred that the proportion of the polymer particles with a particle size in one Range of 300 to 600 microns at least 30% by weight, more preferably at least 40% by weight, and most preferably at least 50% by weight, based on the total weight the postcrosslinked, water-absorbing polymer particles is.

• (α1) 20-99,999 Gew.-%, bevorzugt 55-98,99 Gew.-% und besonders bevorzugt 70-98,79 Gew.-% polymerisierten, ethylenisch ungesättigten, säuregruppentragenden Monomeren oder deren Salze oder polymerisierten, ethylenisch ungesättigten, einen protonierten oder quarternierten Stickstoff beinhaltenden Monomeren, oder deren Mischungen, wobei mindestens ethylenisch ungesättigte, säuregruppenhaltige Monomere, vorzugsweise Acrylsäure, beinhaltende Mischungen besonders bevorzugt sind,
• (α2) 0-80 Gew.-%, vorzugsweise 0-44,99 Gew.-% und besonders bevorzugt 0,1-44,89 Gew.-% polymerisierten, monoethylenisch ungesättigten, mit (α1) copolymerisierbaren Monomeren,
• (α3) 0,001-5 Gew.-%, vorzugsweise 0,01-3 Gew.-% und besonders bevorzugt 0,01-2,5 Gew.-% eines oder mehrerer Vernetzer,
• (α4) 0-30 Gew.-%, vorzugsweise 0-5 Gew.-% und besonders bevorzugt 0,1-5 Gew.-% eines wasserlöslichen Polymeren,
• (α5) 0-20 Gew.-%, vorzugsweise 2,5-15 Gew.-% und besonders bevorzugt 5-10 Gew.-% Wasser, sowie
• (α6) 0-20 Gew.-%, vorzugsweise 0-10 Gew.-% und besonders bevorzugt 0,1-8 Gew.-% eines oder mehrerer Hilfsmittel, wobei die Summe der Gewichtsmengen (α1) bis (α6) 100 Gew.-% beträgt.

In a preferred embodiment of the water-absorbing polymer structures provided in process step i), these are based on

• (α1) 20-99.999 wt .-%, preferably 55-98.99 wt .-% and particularly preferably 70-98.79 wt .-% polymerized, ethylenically unsaturated, acid group-carrying monomers or their salts or polymerized, ethylenically unsaturated, one protonated or quaternized nitrogen-containing monomers, or mixtures thereof, wherein at least ethylenically unsaturated, acid group-containing monomers, preferably acrylic acid-containing mixtures are particularly preferred,
• (α2) 0-80 wt .-%, preferably 0-44.99 wt .-% and particularly preferably 0.1-44.89 wt .-% polymerized, monoethylenically unsaturated, with (α1) copolymerizable monomers,
• (α3) 0.001-5 wt .-%, preferably 0.01-3 wt .-% and particularly preferably 0.01-2.5 wt .-% of one or more crosslinkers,
• (α4) 0-30 wt .-%, preferably 0-5 wt .-% and particularly preferably 0.1-5 wt .-% of a water-soluble polymer,
• (α5) 0-20 wt .-%, preferably 2.5-15 wt .-% and particularly preferably 5-10 wt .-% water, and
• (α6) 0-20 wt .-%, preferably 0-10 wt .-% and particularly preferably 0.1-8 wt .-% of one or more auxiliaries, wherein the sum of the amounts by weight (α1) to (α6) 100 wt .-% is.

The monoethylenically unsaturated acid group-containing monomers (α1) may be partially or completely, preferably partially neutralized. The monoethylenically unsaturated monomers containing acid groups are preferably neutralized to at least 25 mol%, particularly preferably to at least 50 mol% and moreover preferably to 50-80 mol%. In this context is on DE 195 29 348 A1 The disclosure of which is hereby incorporated by reference. The neutralization can be done partially or completely even after the polymerization. Furthermore, the neutralization can be carried out with alkali metal hydroxides, alkaline earth metal hydroxides, ammonia and carbonates and bicarbonates. In addition, every other base is conceivable, which forms a water-soluble salt with the acid. Also a mixed neutralization with different bases is conceivable. Preference is given to neutralization with ammonia and alkali metal hydroxides, particularly preferably with sodium hydroxide and with ammonia.

Furthermore, in the case of a polymer, the free acid groups may predominate, so that this polymer has a pH lying in the acidic range. This acidic water-absorbing polymer may be at least partially neutralized by a polymer having free basic groups, preferably amine groups, which is basic as compared to the acidic polymer. These polymers are referred to in the literature as "Mixed-Bed Ion-Exchange Absorbent Polymers "(MBIEA polymers) are and are among others in the WO 99/34843 A1 disclosed. The revelation of WO 99/34843 A1 is hereby incorporated by reference and thus forms part of the disclosure. Typically, MBIEA polymers are a composition that includes basic polymers capable of exchanging anions and, on the other hand, an acidic polymer capable of exchanging cations as compared to the basic polymer. The basic polymer has basic groups and is typically obtained by the polymerization of monomers bearing basic groups or groups that can be converted to basic groups. These monomers are, above all, those which have primary, secondary or tertiary amines or the corresponding phosphines or at least two of the above functional groups. In particular, ethyleneamine, allylamine, diallylamine, 4-aminobutene, alkoxycycline, vinylformamide, 5-aminopentene, carbodiimide, formaldacin, melamine and the like, as well as their secondary or tertiary amine derivatives, belong to this group of monomers.

Preferred ethylenically unsaturated acid group-containing monomers (α1) are preferably those compounds which are described in the WO 2004/037903 A2 , which is hereby incorporated by reference and therefore considered part of the disclosure, may be mentioned as ethylenically unsaturated monomers (α1) containing acid groups. Particularly preferred ethylenically unsaturated acid group-containing monomers (α1) are acrylic acid and methacrylic acid, with acrylic acid being most preferred.

According to one embodiment the method according to the invention untreated, water-absorbing polymer structures are used, in which the monoethylenically unsaturated, with (α1) copolymerizable Monomers (α2) Acrylamides, methacrylamides or vinylamides are.

preferred (Meth) acrylamides are alkyl-substituted in addition to acrylamide and methacrylamide (Meth) acrylamides or aminoalkyl-substituted derivatives of (meth) acrylamide, such as N-methylol (meth) acrylamide, N, N-dimethylamino (meth) acrylamide, Dimethyl (meth) acrylamide or diethyl (meth) acrylamide. Possible vinylamides are for example N-vinylamides, N-vinylformamides, N-vinylacetamides, N-vinyl-N-methylacetamides, N-vinyl-N-methylformamide, vinylpyrrolidone. Among these monomers especially preferred is acrylamide.

According to one another embodiment the method according to the invention Water-absorbing polymer structures are used in which the monoethylenically unsaturated, with (α1) copolymerizable monomers (α2) water-soluble Are monomers. In this connection, in particular alkoxypolyalkylene oxide (meth) acrylates such as methoxypolyethylene glycol (meth) acrylates preferred.

Of Further, as monoethylenically unsaturated, with (α1) copolymerizable Monomers (α2) water-dispersible monomers are preferred. As dispersible in water Monomers are acrylic esters and methacrylates, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate or butyl (meth) acrylate.

The monoethylenically unsaturated, with (α1) copolymerizable monomers (α2) further include methyl polyethylene glycol allyl ether, vinyl acetate, Styrene and isobutylene.

As crosslinking agents (α3) it is preferred to use those compounds which are known in the WO 2004/037903 A2 as crosslinkers (α3). Among these crosslinkers, water-soluble crosslinkers are particularly preferred. N, N'-methylenebisacrylamide, polyethylene glycol di (meth) acrylates, triallylmethylammonium chloride, tetraallylammonium chloride and allylnonaethylene glycol acrylate prepared with 9 mol of ethylene oxide per mole of acrylic acid are particularly preferred.

When water-soluble Polymers (α4) can water-soluble in the polymer structures Polymers, such as partially or fully saponified polyvinyl alcohol, polyvinylpyrrolidone, Strength or starch derivatives, Polyglycols or polyacrylic acid contained, preferably copolymerized. The molecular weight These polymers are not critical as long as they are water soluble. Preferred water-soluble Polymers are starch or starch derivatives or polyvinyl alcohol. The water-soluble polymers, preferably Synthetic such as polyvinyl alcohol, can also be used as a grafting base for the serve to be polymerized monomers.

When Aids (α6) are preferably settling agents, odor binders, surface-active Agents or antioxidants as well as those additives that are used to manufacture the polymer structures were used (initiators, etc.) in the polymer structures contain.

In a particular embodiment, the water provided in process step i) the polymer structures are based on these at least 50 wt .-%, preferably at least 70 wt .-% and more preferably at least 90 wt .-% on carboxylate-carrying monomers. It is further preferred according to the invention that the component (α1) consists of at least 50 wt .-%, preferably at least 70 wt .-% of acrylic acid, which is preferably at least 20 mol%, more preferably at least 50 mol% and more preferably, it is neutralized in a range of 60 to 85 mol%.

Out the aforementioned monomers, comonomers, crosslinkers, water-soluble Polymers and auxiliaries can be the untreated, water-absorbing Produce polymer structures by different Polymerisationsweisen. For example, in this context, bulk polymerization, which preferably takes place in kneading reactors such as extruders, solution polymerization, Spraypolymerisati on, inverse emulsion polymerization and inverse To call suspension polymerization.

Preferably, the solution polymerization is carried out in water as a solvent. The solution polymerization can be continuous or discontinuous. From the prior art, a wide range of possible variations in terms of reaction conditions such as temperatures, type and amount of initiators and the reaction solution can be found. Typical processes are described in the following patents: US 4,286,082 . DE 27 06 135 . US 4,076,663 . DE 35 03 458 . DE 40 20 780 . DE 42 44 548 . DE 43 23 001 . DE 43 33 056 . DE 44 18 818 , The disclosures are hereby incorporated by reference and thus are considered part of the disclosure.

The polymerization is initiated as usual by an initiator. As initiators for the initiation of the polymerization, it is possible to use all initiators which form free radicals under the polymerization conditions and which are customarily used in the production of superabsorbers. It is also possible to initiate the polymerization by the action of electron beams on the polymerizable, aqueous mixture. However, the polymerization can also be initiated in the absence of initiators of the abovementioned type by the action of high-energy radiation in the presence of photoinitiators. Polymerization initiators may be dissolved or dispersed in a solution of monomers according to the invention. Suitable initiators are all compounds which decompose into free radicals and which are known to the person skilled in the art. These include in particular those initiators already in the WO 2004/037903 A2 be mentioned as possible initiators.

Especially is preferred for the preparation of water-absorbing polymer structures a redox system consisting of hydrogen peroxide, sodium peroxodisulfate and ascorbic acid used.

Also the inverse suspension and emulsion polymerization can be used for the preparation be applied to the polymer structure. According to these processes, one becomes aqueous partially neutralized solution the monomers (α1), and (α2), optionally including water-soluble polymers and auxiliaries, with the aid of protective colloids and / or emulsifiers in a hydrophobic, organic solvents dispersed and initiated by radical initiators the polymerization. The crosslinkers are either dissolved in the monomer solution and are combined with it dosed or separately and optionally added during the polymerization. Possibly the addition of a water-soluble Polymers (α4) as a grafting over the monomer solution or by direct submission to the oil phase. Subsequently, will the water is azeotropically removed from the mixture and the polymer filtered off.

Furthermore, both in the solution polymerization and in the inverse suspension and emulsion polymerization, the crosslinking can be effected by copolymerization of the polyfunctional crosslinker dissolved in the monomer solution and / or by reaction of suitable crosslinkers with functional groups of the polymer during the polymerization steps. The methods are for example in the publications US 4,340,706 . DE 37 13 601 . DE 28 40 010 and WO 96/05234 A1 described, the corresponding disclosure of which is hereby incorporated by reference.

The in the solution polymerization or inverse suspension and emulsion polymerization The hydrogels obtained in the polymerization are used in another Dried process step.

Especially in the case of solution polymerization However, it is preferred that the hydrogels first crushed before drying become. This comminution is carried out by comminution devices known to the person skilled in the art, like a meat grinder.

The drying of the hydrogel is preferably carried out in suitable dryers or ovens. exemplary be rotary kilns, fluidized bed dryers, plate dryers, paddle dryers or infrared dryers called. Furthermore, it is preferred according to the invention that the drying of the hydrogel to a water content of 0.5 to 25 wt .-%, preferably from 1 to 10 wt .-%, wherein the drying temperatures usually in a range of 100 to 200 ° C. lie.

The after drying obtained water-absorbing polymer structures can, especially when they are obtained by solution polymerization were still ground in a further process step and on a screened the desired grain size mentioned above. The grinding The dried, water-absorbing polymer structure is preferably carried out in suitable mechanical crushers, such as a ball mill.

• (A) die maximale Aufnahme gemäß ERT 440.2-02 (im Falle von Partikeln bestimmt für die gesamte Partikelgrößenfraktion) von 0,9 Gew.-%er NaCl-Lösung liegt in einem Bereich von mindestens 10 bis 1000 g/g, vorzugswei se im Bereich von 20 bis 500 g/g und darüber hinaus bevorzugt im Bereich von 50 bis 100 g/g,
• (B) der gemäß ERT 470.2-02 (im Falle von Partikeln bestimmt für die gesamte Partikelgrößenfraktion) extrahierbare Anteil nach 16 Stunden beträgt weniger als 30 Gew.-%, vorzugsweise weniger als 20 Gew.-% und darüber hinaus bevorzugt weniger als 15 Gew.-%, jeweils bezogen auf das unbehandelte, wasserabsorbierende Polymergebilde,
• (C) die Schüttdichte gemäß ERT 460.2-02 (im Falle von Partikeln bestimmt für die gesamte Partikelgrößenfraktion) liegt im Bereich von 300 bis 1000 g/l, vorzugsweise im Bereich von 400 bis 900 g/l und darüber hinaus bevorzugt von 500 bis 800 g/l,
• (D) der pH-Wert gemäß ERT 400.2-02 (im Falle von Partikeln bestimmt für die gesamte Partikelgrößenfraktion) von 1 g des wasserabsorbierenden Polymervorprodukts in 11 Wasser liegt im Bereich von 4 bis 10, vorzugsweise im Bereich von 4,5 bis 9 und darüber hinaus bevorzugt im Bereich von 5 bis 8,
• (E) die nach ERT 442.2-02 (im Falle von Partikeln für die gesamte Partikelfraktion) bestimmte Absorption gegen einen Druck von 0,3 psi liegt in einem Bereich von 10 bis 26 g/g, vorzugsweise in einem Bereich von 13 bis 25 g/g und am meisten bevorzugt in einem Bereich von 13,5 bis 24 g/g;
• (F) die nach ERT 441.2-02 (im Falle von Partikeln für die gesamte Partikelfraktion) bestimmte als CRC bezeichnete Retention liegt in einem Bereich von 20 bis 50 g/g, vorzugsweise in einem Bereich von 25 bis 45 g/g und am meisten bevorzugt in einem Bereich von 27 bis 40 g/g.

In a preferred embodiment, the untreated absorbent polymer structure provided in process step i) of the process according to the invention exhibits at least one of the following properties (ERT = EDANA Recommended Test):

• (A) the maximum uptake according to ERT 440.2-02 (in the case of particles determined for the total particle size fraction) of 0.9 wt .-% of NaCl solution is in a range of at least 10 to 1000 g / g, vorzugswei in the Range of 20 to 500 g / g and moreover preferably in the range of 50 to 100 g / g,
• (B) the extractable content according to ERT 470.2-02 (in the case of particles determined for the total particle size fraction) after 16 hours is less than 30 wt .-%, preferably less than 20 wt .-% and more preferably less than 15 wt .-%, in each case based on the untreated, water-absorbing polymer structure,
• (C) the bulk density according to ERT 460.2-02 (in the case of particles determined for the entire particle size fraction) is in the range of 300 to 1000 g / l, preferably in the range of 400 to 900 g / l and more preferably from 500 to 800 g / l,
• (D) the pH according to ERT 400.2-02 (in the case of particles determined for the total particle size fraction) of 1 g of the water-absorbing polymer precursor in 11 water is in the range of 4 to 10, preferably in the range of 4.5 to 9 and moreover, preferably in the range of 5 to 8,
• (E) the absorbance against a pressure of 0.3 psi determined according to ERT 442.2-02 (in the case of particles for the total particle fraction) is in a range of 10 to 26 g / g, preferably in a range of 13 to 25 g / g, and most preferably in a range of from 13.5 to 24 g / g;
• (F) the retention designated CRT according to ERT 441.2-02 (in the case of particles for the total particle fraction) is in a range of 20 to 50 g / g and preferably in a range of 25 to 45 g / g and most preferably in a range of 27 to 40 g / g.

According to one particular embodiment the method according to the invention in process step i) polymer structures are provided which by the following properties or property combinations (A), (B), (C), (D), (E), (F), (A) (E), (B) (E), (C) (E), (D) (E), (E) (F), (B) (E), (B) (F), (E) (F) (G), wherein (D) (e), (F) and (E) (F) and (D) (E) (F) are most preferred and (D) (E) (F) about that addition is preferred.

in the Process step ii) of the process according to the invention are described in the Process step i) provided untreated, water-absorbing Polymeric structure with a salt comprising a divalent or higher Cation of a metal and at least one organic base as anion brought into contact.

It is preferred that the divalent or higher valent cation of a metal is selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Al ³⁺ , Fe ²⁺ , Fe ³⁺ , Ga ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Cu ²⁺ and Zn ²⁺ , with Al ^{3+ being} most preferred.

at the organic base is preferably at least one partially deprotonated mono-, di- or tricarboxylic acid, wherein deprotonated monocarboxylic acids are particularly preferred. Also preferred are hydroxycarboxylic acids, wherein at least partially deprotonated mono-, di- or Hydroxitricarbonsäuren preferred and monohydroxycarboxylic acids are particularly preferred.

Particularly preferred anions are, in particular, the corresponding bases of the following acids: anisic acid, benzoic acid, formic acid, valeric acid, citric acid, glyoxylic acid, glycolic acid, glycerophosphoric acid, glutaric acid, chloroacetic acid, chloropropionic acid, cinnamic acid, succinic acid, acetic acid, tartaric acid, lactic acid, pyruvic acid, fumaric acid, propionic acid, 3 Hydroxypropionic, malonic, maleic, butyric, isobutyric, imidinoacetic, malic, isothionic, methylmaleic, adipic, itaconic, crotonic, oxalic, salicylic, gluconic, gallic, sorbic, gluconic, fatty, especially stearic and adipic, and p -oxybenzoic acids. Under these Bases most preferred are tartrate and lactate, with lactate being most preferred.

According to a particularly preferred embodiment of the process according to the invention, a salt which contains aluminum lactate is used as the salt in process step ii). Preferably, this salt is at least 50% by weight, more preferably at least 75% by weight, and most preferably 100% by weight, based on aluminum lactate. It is further preferred that one or two or more further cations are present in addition to the aluminum lactate. These are preferably selected from the group consisting of: mono-, di- or higher-valent cation of a metal, again selected from the group consisting of Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Al ³⁺ , Fe ²⁺ , Fe ^{3 +} , Ga ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ , Cu ²⁺ and Zn ²⁺ . In addition, in addition to the aluminum lactate in the salt also other anions may be present. Here, the anions described above are preferred. Further, in addition to aluminum lactate and oxides or mixed oxides of other metals may be present, the oxides of the metal ions mentioned in this section are preferred. Thus, in connection with a solution containing the salt, it may be preferred that it additionally contains an alkali metal or alkaline earth metal salt, preferably an alkali metal salt of one of the abovementioned anions, preferably the main salt anion present in the solution as secondary salt. These preferably include lithium and sodium lactate. Preferably, the amount of the minor salt is 0.001 to 25 wt .-%, preferably 0.01 to 17 wt .-% and particularly preferably 0.1 to 12 wt .-%, each based on the main salt.

In another embodiment of the method according to the invention, it is preferable that another anion is present, that of the organic base is different. This is preferably an inorganic Base. This inorganic base is preferably a deprotonated one inorganic acid. As such acids especially the acids which can give off two and more protons. this includes especially sulfur, nitrogen or phosphorus-containing acids are preferred, In addition, sulfur or phosphorus-containing acid is moreover preferred. Sulfur-containing acids have proven particularly useful, including in particular the sulfuric acid and thus sulfate as its salt for the base. According to one particularly preferred embodiment the method according to the invention a salt is used as salt in step ii), which includes aluminum sulfate. Preferably, this is based Salt to at least 50 wt .-%, moreover preferably to at least 75% by weight, and most preferably 100% by weight, of aluminum sulfate. The two different anions can be in a ratio of 1: 100 to 100: 1, preferably in a ratio of 1:10 to 10: 1 and more preferably from 1: 5 to 5: 1 are used.

Farther is it preferred according to the invention that the untreated, water-absorbing polymer structure in the process step ii) from 0.001 to 10% by weight, more preferably from 0.01 to 7.5 Wt .-% and most preferably with 0.1 to 5 wt .-%, each based on the weight of the untreated, water-absorbing polymer structure, of the salt or salts.

The contacting the salt with the untreated, water-absorbing Polymer structure in process step ii) of the method according to the invention is preferably carried out by mixing the two components, wherein For this purpose, suitable mixing units, in particular the Patterson-Kelley mixers, DRAIS turbulence mixers, Lödige, Ruberg mixer, screw mixer, plate mixer and fluidized bed mixer or continuously operating vertical mixers in which the polymer structure by means of rotating blades in fast frequency mixed (Schugi mixer) are.

Furthermore, the salt can be brought into contact with the untreated, water-absorbing polymer structure in the form of a fluid F ₁ comprising a solvent and the salt dissolved or dispersed in this solvent, or in dry form as a salt powder. Suitable solvents are, in addition to water, especially miscible with water, organic solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1,2-propanediol, 1,3-propanediol, 1-butanol, 2-butanol, tert. Butanol, isobutanol or mixtures of organic solvents or mixtures of water with one or more of these organic solvents, with water being the solvent most preferred. When the untreated water-absorbing polymeric formations comprising contacted with the fluid F _1, the solvent and the salt in contact, so it is further preferred that this fluid F _1, the salt in an amount in a range of in a range of 0.1 to 50 Wt .-%, particularly preferably 1 to 40 wt .-% and most preferably 5 to 25 wt .-%, each based on the total weight of the fluid F ₁ includes.

According to a particularly preferred embodiment of the process according to the invention, the contacting of the untreated, water-absorbing polymer structure with the salt takes place in process step ii) in the presence of at least 0.01% by weight and at most 15% by weight, particularly preferably at least 0, 1 and at most 10% by weight, more preferably at least 0.5 and at most 5 Wt .-%, moreover preferably of at least 1 and at most 2.5 wt .-% of a solvent, wherein the above-mentioned wt .-% - are based on the weight of the untreated, water-absorbing polymer structure.

Farther it may be advantageous that contacting the untreated, water-absorbing polymer structures with the salt in the process step ii) at a temperature in a range of 30 to 210 ° C, especially preferably from 50 to 200 ° C and most preferably in a range of 160 to 195 ° C. The contacting is preferably done over a period of time in one Be rich from 10 to 300 minutes, preferably in a range of 15 to 180 minutes, and more preferably in a range of 20 to 120 minutes.

According to one particular embodiment the method according to the invention for the treatment of the surface water-absorbing polymer structures are in the process step ii) the untreated, water-absorbing polymer structures with the Salt contacted, wherein the salt is in powder form. The bringing into contact of the water-absorbing polymer structure with the salt in this case takes place in the absence of a solvent.

• i) Bereitstellen des unbehandelten, vorzugsweise jedoch bereits oberflächennachvernetzten wasserabsorbierenden Polymergebildes;
• ii) in Kontakt bringen des unbehandelten, vorzugsweise jedoch bereits oberflächennachvernetzten wasserabsorbierenden Polymergebildes mit einer Feinstteilchenkomponente umfassend das Salz bei einer Temperatur in einem Bereich von 30 bis 300°C, besonders bevorzugt von 100 bis 250°C, darüber hinaus bevorzugt in einem Bereich von 110 bis 200°C und am meisten bevorzugt in einem Bereich von 115 bis 180°C. In einer anderen Ausgestaltung erfolgt das in Kontakt bringen bei einer Temperatur in einem Bereich von 30 bis 200°C, darüber hinaus bevorzugt von 50 bis 160°C, darüber hinaus noch mehr bevorzugt von 50 bis 160°C und am meisten bevorzugt von 100 bis 140°C.

In this particular embodiment of the process according to the invention for producing water-absorbing polymer structures, the process preferably comprises the following process steps:

• i) providing the untreated, but preferably already surface-postcrosslinked water-absorbing polymer structure;
• ii) contacting the untreated, but preferably already surface-postcrosslinked, water-absorbing polymer structure having a fines particle component comprising the salt at a temperature in a range of 30 to 300 ° C, more preferably 100 to 250 ° C, more preferably in a range of 110 to 200 ° C, and most preferably in a range of 115 to 180 ° C. In another embodiment, the contacting is carried out at a temperature in a range of 30 to 200 ° C, more preferably 50 to 160 ° C, still more preferably 50 to 160 ° C, and most preferably 100 to 140 ° C.

In In this context, it is particularly preferred that at least 50 wt .-%, particularly preferably at least 75 wt .-%, beyond even more preferably at least 95% by weight, and most preferably at least 99% by weight of the salt present in powder form mean particle diameter (weight average) in a range from 10 to 1,000 μm, preferably 50 microns up to 800 μm, more preferably from 100 to 600 microns, and most preferably from 200 to 400 μm each determined by methods known to those skilled in the art for particle size determination, for example by sieve analysis or by means of a Coulter counter.

Farther it may in this particular embodiment of the method according to the invention be preferred if the Feinstteilchenkomponente next to the powdered salt additionally includes a binder, this binder also preferably in particulate Form is present and in particular at least 50 wt .-%, especially preferably at least 75% by weight, moreover still more preferred at least 95% by weight, and most preferably at least 99% % By weight on particles having an average particle diameter (weight average) in a range of 10 to 1,000 μm, preferably 50 μm to 800 μm, especially preferably from 100 to 600 μm and most preferably from 200 to 400 μm, each determined by methods known in the art for particle size determination, for example by sieve analysis or by means of a Coulter counter.

one further embodiment of the present invention corresponds, when the salt is added as a solid to the postcrosslinking solution. in this connection it is preferred that the salt at the latest when applying the Nachvernetzungslösung on the untreated, preferably not yet postcrosslinked, polymer structure in the postcrosslinking solution solved is present. The thus obtained untreated polymer structure, postcrosslinkers and Salt-containing mixture is then the usual for post-crosslinking and subjected to the temperature treatment described herein.

In another embodiment of the invention, the salt is added as a preferably aqueous solution of the postcrosslinking solution. This produces postcrosslinker salt solutions which preferably have a salt concentration in the range from 1 to 50% by weight, preferably in the range from 10 to 40% by weight and more preferably in the range from 15 to 35% by weight, in each case on the amount of solvent of Nachvernetzungslösung. The untreated polymer structure, postcrosslinker and salt-containing mixture thus obtained is then the temperature treatment customary for the post-crosslinking and described herein subjected. This can be stabilized by the addition of the secondary salt explained in more detail below, where the amounts of secondary salt indicated below are also preferred here.

In In this context, it is particularly preferred that the binder as a binder main component includes an organic compound, wherein the organic compound is preferably a solid at 20 ° C is.

Especially it is preferred that the organic compound is a preferred linear polymer is preferably a linear polymer selected from the group comprising polyurethanes, polyesters, polyamides, polyesteramides, Polyolefins, polyvinyl esters, polyethers, polystyrenes, polyimides, in particular polyetherimides, polyimines, sulfur polymers, in particular Polysulfone, polyacetals, in particular polyoxymethylenes, fluoroplastics, in particular polyvinylidene fluoride, styrene-olefin copolymers, polyacrylates, Ethylene-vinyl acetate copolymers or mixtures of two or more said polymers, wherein among these polymers polycondensates and among these polyethers particularly preferred and linear polyethers most preferred.

Especially suitable linear polyethers include polyalkylene glycols, in particular Polyethylene glycols, polypropylene glycols, poly (ethylene / propylene) glycols with random or block-like arrangement of the ethylene or Propylene monomers or mixtures of at least two of these polyalkylene glycols.

Other suitable, preferably linear polymers are those polymers which are described in the DE-A-103 34 286 as "thermoplastic adhesives" DE-A-103 34 286 in terms of thermoplastic adhesives is hereby incorporated by reference and forms part of the disclosure of the present invention.

If In addition to the salt, a binder is used, it is particularly preferred that bring the untreated, water-absorbent Polymeric structure with the Feinstteilchenkomponente at a temperature in a range of 30 to 200 ° C, more preferably from 50 to 160 ° C, and most preferably in a range of 70 to 140 ° C he follows. At these temperatures, it comes in particular to a Immobilization of the fines on the surface of the untreated, water-absorbing polymer structure.

The Amount of binder, if used, is preferably in one Range of 0.0001 to 5 wt .-% and particularly preferably in one Range from 0.001 to 2 wt .-%, each based on the weight of water-absorbing polymer structures. The weight ratio between Feinstteilchenkomponente and binder is preferably in one Range of fines component: binder from 20: 1 to 1:20, more preferably from 10: 1 to 1:10 and most preferably from 10: 1 to 2: 1.

at the above-described, particular embodiment of the method according to the invention, when a powdered Salt is brought into contact with the water-absorbing polymer structures, includes the process in addition to providing the untreated, water-absorbing polymer structure in process step i) also the provision of a very fine particle component comprising the powdery Salt and optionally the powdered binder. Regarding the manner of contacting the fines component with the untreated, water-absorbing polymer structure are different process guides conceivable.

Farther It may be in connection with the above-described, special embodiment of the method according to the invention, in the case of a pulverfömiges Salt brought into contact with the water-absorbing polymer structure will be advantageous if the process step ii) still a further process step ii ') is followed, in which the mixture of untreated, water-absorbing polymer structure and Feinstteilchenkomponente still for a period in a range of 10 minutes to 5 hours, especially preferably from 30 minutes to 3 hours is mixed to one as possible homogeneous distribution of Feinstteilchen or Feinstteilchenagglomerate and the absorbent polymer structures, to which the person skilled in the art known mixing devices can be used. In this further process step may be the mixture of untreated, water-absorbing polymer structure and ultrafine particle component with the temperature that they after the Immobilizing in process step ii), in the mixer are introduced, the mixture then in the course of mixing preferably steadily to a lower temperature, preferably to room temperature, cooled can be.

• iii) Oberflächennachvernetzung des wasserabsorbierenden Polymergebildes,

wobei der Verfahrensschritt iii) vor, während oder nach dem Verfahrensschritt ii) durchgeführt werden kann.According to a particular embodiment of the method according to the invention, the method comprises ren in addition to the process steps i) and ii) the process step

• iii) surface postcrosslinking of the water-absorbing polymer structure,

wherein the method step iii) before, during or after the method step ii) can be carried out.

In the surface postcrosslinking, the dried polymer structures or the not yet dried, but preferably already comminuted hydrogel are brought into contact with a preferably organic, chemical surface postcrosslinker. In this case, the postcrosslinker, in particular if it is not liquid under the postcrosslinking conditions, is preferably brought into contact with the polymer particles or the hydrogel in the form of a fluid F ₂ comprising the postcrosslinker and a solvent. Preferred solvents here are those which have already been mentioned as solvents in connection with the fluid F ₁ . Furthermore, it is preferred that the postcrosslinker in the fluid F ₂ in an amount in a range of 5 to 75 wt .-%, particularly preferably 10 to 50 wt .-% and most preferably 15 to 40 wt .-%, based on the total weight of the fluid F ₂ , is included.

The bringing into contact of the polymer structure or of the comminuted hydrogel with the fluid F ₂ comprising the postcrosslinker preferably takes place in the process according to the invention by good mixing of the fluid F ₂ with the polymer structure, suitable mixing units for applying the fluid F ₂ again being the Patterson-Kelley Mixers, DRAIS turbulence mixers, Lödigemischer, Ruberg mixers, screw mixers, plate mixers and fluidized bed mixers and continuously operating vertical mixers in which the polymer structure by means of rotating blades in rapid frequency is mixed (Schugi mixer) are.

at the post-crosslinking, the water-absorbing polymer structure is preferably with at most 20 Wt .-%, more preferably with at most 15 wt .-%, beyond preferably with at most 10% by weight, above even more preferably with at most 5% by weight of solvent, preferably water, in each case based on the weight of the water-absorbing Polymeric, brought into contact.

In the case of polymer structures in the form of preferably spherical particles, it is further preferred according to the invention for the contacting to take place so that only the outer area but not the inner area of the particulate polymer structures are brought into contact with the fluid F ₂ and thus with the postcrosslinker.

As postcrosslinkers which are used in the process according to the invention, compounds are preferably understood which have at least two functional groups which can react with functional groups of a polymer structure in a condensation reaction (= condensation crosslinker), in an addition reaction or in a ring opening reaction. As postcrosslinkers, preference is given in the process according to the invention to those described in US Pat WO 2004/037903 A2 were called as crosslinkers of crosslinking classes II.

Under These compounds are particularly preferably crosslinking crosslinkers as postcrosslinkers such as diethylene glycol, triethylene glycol, polyethylene glycol, Glycerol, polyglycerol, propylene glycol, diethanolamine, triethanolamine, Polyoxypropylene, oxyethylene-oxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene, Trimethylolpropane, pentaerythritol, polyvinyl alcohol, sorbitol, 1,3-dioxolan-2-one (Ethylene carbonate), 4-methyl-1,3-dioxolan-2-one (Propylene carbonate), 4,5-dimethyl-1,3-dioxolan-2-one, 4,4-dimethyl-1,3-dioxolan-2-one, 4-ethyl-1,3-dioxolan-2-one, 4-hydroxymethyl-1,3-dioxolan-2-one, 1,3-dioxan-2-one, 4-methyl-1,3-dioxan-2 on, 4,6-dimethyl-1,3-dioxane-2-one as well as 1,3-dioxolan-2-one.

After the polymer structures or hydrogels have been brought into contact with the postcrosslinker or with the fluid F ₂ containing the postcrosslinker, they are heated to a temperature in the range of 50 to 300 ° C, preferably 75 to 275 ° C and particularly preferably 150 to Heated to 250 ° C, so that, preferably, whereby the outer region of the polymer structures is more crosslinked compared to the interior (= post-crosslinking). The duration of the heat treatment is limited by the risk that the desired property profile of the polymer structures is destroyed as a result of the action of heat.

The surface modification described above by post-crosslinking before, during or after the process step ii).

If the post-crosslinking takes place before process step ii), surface-postcrosslinked water-absorbing polymer structures are already brought into contact with the salt in process step ii) either in dry form or in the form of fluid _F1 .

• – jeweils in Abwesenheit eines Lösungsmittels,
• – in Form der Fluide F₁ und F₂, in Form eines gemeinsamen Fluids F₃, umfassend das Lösungsmittel sowie den Nachvernetzer und das Salz oder aber
• – das Salz in Abwesenheit eines Lösungsmittels und der Nachvernetzer in Form des Fluids F₂

in Kontakt gebracht und anschließend die so erhaltene Mischung zum Zwecke der Nachvernetzung auf die vorstehend genannten Temperaturen erhitzt.If the postcrosslinking takes place during process step ii), first the untreated, water-absorbing polymer structures with the postcrosslinker and the salt are obtained

• In each case in the absence of a solvent,
• In the form of the fluids F ₁ and F ₂ , in the form of a common fluid F ₃ , comprising the solvent and the postcrosslinker and the salt or else
• The salt in the absence of a solvent and the postcrosslinkers in the form of the fluid F ₂

brought into contact and then heated, the mixture thus obtained for the purpose of post-crosslinking to the above temperatures.

If the post-crosslinking takes place after process step ii), the untreated, water-absorbing polymer structures are first brought into contact with the salt in the manner described above, if appropriate in the absence of an organic solvent or as fluid F ₁ , and then in this way Way surface-modified, water-absorbing polymer structures surface post-crosslinked.

• A1 einen gemäß der hierin beschriebenen Testmethode bestimmte Saline Flow Conductivity (SFC) von mehr als 115 × 10^–7 cm³s/g, vorzugsweise von mehr als 125 × 10^–7 cm³s/g, ferner bevorzugt von mehr als 135 × 10^–7 cm³s/g und weiterhin bevorzugt von mehr als 145 × 10^–7 cm³s/g sowie darüber hinaus bevorzugt mehr als 165 × 10^–7 cm³s/g;
• B1 eine nach ERT 442.2-02 bestimmte Absorption gegen einen Druck von 0,7 psi (AAP_0.7) von mehr als 25,9 g/g, vorzugsweise von mehr als 26,4 g/g, ferner bevorzugt von mehr als 26,9 g/g und darüber hinaus bevorzugt von mehr als 27, 5 g/g;
• C1 eine nach ERT 441.2-02 bestimmte Retention (CRC) von mindestens 25 g/g, vorzugsweise mindestens 27 g/g, weiterhin bevorzugt mehr als 28 g/g und darüber hinaus bevorzugt mindestens 29 g/g; sowie
• D1 eine Teilchengrößenverteilung mit mindestens 80 Gew.-%, vorzugsweise mindestens 85 Gew.-%, bevorzugt mindestens 90 Gew.-% und besonders bevorzugt mindestens 95 Gew.-% der Teilchen des wasserabsorbierenden Polymergebildes in einem Teilchengrößenbereich von 150 bis 850 μm, wobei mindestens 5 Gew.-%, vorzugsweise mindestens 8 Gew.-% und besonders bevorzugt mindestens 12 Gew.-% der Teilchen des wasserabsorbierenden Polymergebildes eine Teilchengröße in einem Bereich von 150 bis 250 μm aufweisen. Darüber hinaus ist es bevorzugt, wenn die Menge der Teilchen des wasserabsorbierenden Polymergebildes im Bereich von 150 bis 250 μm in einem Bereich von 5 bis 30 Gew.-%, vorzugsweise in einem Bereich von 7 bis 25 Gew.-% und darüber hinaus bevorzugt in einem Bereich von 10 bis 20 Gew.-% sowie ferner bevorzugt in einem Bereich von 11 bis 15 Gew.-%, jeweils bezogen auf die Gesamtmenge der Teilchen des wasserabsorbierenden Polymergebildes, liegen.

A further object of the present invention is to provide a water-absorbing polymer structure comprising an inner area and an outer area surrounding the inner area such that more than 80, preferably at least 85 and more preferably at least 90 wt.%, More preferably more than 95 wt %, based in each case on the water-absorbing polymer structure, in the range of 50 to 90 mol%, preferably in the range of 60 to 85 mol% and particularly preferably in the range of 65 to 80 mol% of neutralized acrylic acid , having the following characteristics:

• A1 determines a Saline Flow Conductivity (SFC) of more than 115 x 10 ^-7 cm ³ s / g, preferably greater than 125 x 10 ^-7 cm ³ s / g, further preferably greater than 135 x, determined according to the test method described herein 10 ^-7 cm ³ s / g and further preferably more than 145 × 10 ^-7 cm ³ s / g, and more preferably more than 165 × 10 ^-7 cm ³ s / g;
• B1, an absorption determined according to ERT 442.2-02 against a pressure of 0.7 psi (AAP _0.7 ) of more than 25.9 g / g, preferably of more than 26.4 g / g, more preferably of more than 26.9 g / g and more preferably greater than 27. 5 g / g;
• C1 a retention (CRC) determined according to ERT 441.2-02 of at least 25 g / g, preferably at least 27 g / g, more preferably more than 28 g / g and moreover preferably at least 29 g / g; such as
• D1 has a particle size distribution of at least 80% by weight, preferably at least 85% by weight, preferably at least 90% by weight and particularly preferably at least 95% by weight of the particles of the water-absorbing polymer structure in a particle size range of 150 to 850 μm, at least 5% by weight, preferably at least 8% by weight and more preferably at least 12% by weight of the particles of the water-absorbing polymer structure have a particle size in a range of 150 to 250 μm. In addition, it is preferable that the amount of the particles of the water-absorbent polymer structure is in the range of 150 to 250 μm in a range of 5 to 30% by weight, preferably in the range of 7 to 25% by weight, and more preferably in a range of 10 to 20 wt .-% and further preferably in a range of 11 to 15 wt .-%, each based on the total amount of the particles of the water-absorbing polymer structure lie.

• A2 einen gemäß der hierin beschriebenen Testmethode bestimmte Saline Flow Conductivity (SFC) von mehr als 89 × 10^–7 cm³s/g, bevorzugt mehr als 115 × 10^–7 cm³s/g, vorzugsweise von mehr als 125 × 10^–7 cm³s/g, ferner bevorzugt von mehr als 135 × 10^–7 cm³s/g und weiterhin bevorzugt von mehr als 145 × 10^–7 cm³s/g sowie darüber hinaus bevorzugt mehr als 160 × 10⁴ cm³s/g;
• B2 eine nach ERT 442.2-02 bestimmte Absorption gegen einen Druck von 0,7 psi (AAP_0.7) von mehr als 24,7 g/g, bevorzugt von mehr als 25,9 g/g, vorzugsweise von mehr als g/g 26,5, ferner bevorzugt von mehr als 27 g/g und darüber hinaus bevorzugt von mehr als 27, 5 g/g;
• C2 eine nach ERT 441.2-02 bestimmte Retention (CRC) von mindestens 25 g/g, vorzugsweise mindestens 27 g/g, weiterhin bevorzugt mehr als 27,2 g/g, noch mehr bevorzugt mehr als 28 g/g und darüber hinaus bevorzugt mindestens 29 g/g; sowie vorzugsweise
• D2 eine Teilchengrößenverteilung mit mindestens 80 Gew.-%, vorzugsweise mindestens 85 Gew.-%, bevorzugt mindestens 90 Gew.-% und besonders bevorzugt mindestens 95 Gew.-% der Teilchen des wasserabsorbierenden Polymergebildes in einem Teilchengrößenbereich von 150 bis 850 μm, wobei mindestens 5 Gew.-%, vorzugsweise mindestens 8 Gew.-% und besonders bevorzugt mindestens 12 Gew.-% der Teilchen des wasserabsorbierenden Polymergebildes eine Teilchengröße in einem Bereich von 150 bis 250 μm aufweisen. Darüber hinaus ist es bevorzugt, wenn die Menge der Teilchen des wasserabsorbierenden Polymergebildes im Bereich von 150 bis 250 μm in einem Bereich von 5 bis 30 Gew.-%, vorzugsweise in einem Bereich von 7 bis 25 Gew.-% und darüber hinaus bevorzugt in einem Bereich von 10 bis 20 Gew.-% sowie ferner bevorzugt in einem Bereich von 11 bis 15 Gew.-%, jeweils bezogen auf die Gesamtmenge der Teilchen des wasserabsorbierenden Polymergebildes, liegen.

A further object of the present invention is to provide a water-absorbing polymer structure comprising an inner area and an outer area surrounding the inner area such that at least 80, preferably at least 90 and more preferably at least 95% by weight, based in each case on the water-absorbing polymer structure in the range of 50 to 90 mol%, preferably in the range of 60 to 85 mol%, and more preferably in the range of 65 to 80 mol% of neutralized acrylic acid based, the outer region of the water-absorbing polymer structure containing a salt or higher cation of a metal, wherein the water-absorbing polymer structure has the following properties:

• A2 shows a saline flow conductance (SFC) of more than 89 × 10 ^-7 cm ³ s / g, preferably more than 115 × 10 ^-7 cm ³ s / g, preferably more than 125 × 10 ^, determined according to the test method described herein ^{. 7} cm ³ s / g, furthermore preferably more than 135 × 10 ^-7 cm ³ s / g and furthermore preferably more than 145 × 10 ^-7 cm ³ s / g and moreover more than 160 × 10 ⁴ cm ³ s / g;
• B2 is an absorption determined according to ERT 442.2-02 against a pressure of 0.7 psi (AAP _0.7 ) greater than 24.7 g / g, preferably greater than 25.9 g / g, preferably greater than g / g 26 , 5, further preferably greater than 27 g / g and more preferably greater than 27, 5 g / g;
• C2 is a retention (CRC) determined according to ERT 441.2-02 of at least 25 g / g, preferably at least 27 g / g, more preferably more than 27.2 g / g, even more preferably more than 28 g / g and moreover preferred at least 29 g / g; and preferably
• D2 has a particle size distribution of at least 80% by weight, preferably at least 85% by weight, preferably at least 90% by weight and particularly preferably at least 95% by weight of the particles of the water-absorbing polymer structure in a particle size range of 150 to 850 μm, at least 5% by weight, preferably at least 8% by weight and more preferably at least 12% by weight of the particles of the water-absorbing polymer structure have a particle size in a range of 150 to 250 μm. In addition, it is preferable that the amount of the particles of the water-absorbent polymer structure is in the range of 150 to 250 μm in a range of 5 to 30% by weight, preferably in the range of 7 to 25% by weight, and more preferably in a range of 10 to 20 wt .-% and further preferably in a range of 11 to 15 wt .-%, each based on the total amount of the particles of the water-absorbing polymer structure lie.

in the Related to the properties D1 and D2 it corresponds to one Another embodiment of the present invention that at least 80% by weight, preferably at least 85% by weight, preferably at least 90 wt .-% and particularly preferably at least 95 wt .-% of the particles of the water-absorbing polymer structure in a particle size range from 150 to 850 μm , wherein, in each case based on the amount of the particles with a particle size of 150 up to 85 μm, 1 to 20 wt .-%, preferably 5 to 17 wt .-% and particularly preferably 7 to 15 wt .-% of a particle size in the range from 150 to 250 μm, 15 to 79 wt .-%, preferably 20 to 60 wt .-% and particularly preferably 30 to 50% by weight of a particle size in one Range of more than 250 to 600 microns and the respective remaining amount of the particles to 100 wt .-% one Particle size in one Range of more than 600 to 850 microns exhibit.

in the Related to the properties D1 and D2 it corresponds to one Another embodiment of the present invention that at least 80% by weight, preferably at least 85% by weight, preferably at least 90 wt .-% and particularly preferably at least 95 wt .-% of the particles of the water-absorbing polymer structure in a particle size range from 150 to 850 μm , wherein, in each case based on the amount of the particles with a particle size of 150 up to 850 μm, 1 to 20 wt .-%, preferably 5 to 17 wt .-% and particularly preferably 7 to 15 wt .-% of a particle size in the range from 150 to 250 μm, 30 to 79 wt .-%, preferably 40 to 79 wt .-% and particularly preferably 60 to 78 wt .-% of a particle size in one Range of more than 250 to 600 microns and the respective remaining amount of the particles to 100 wt .-% one Particle size in one Range of more than 600 to 850 microns exhibit.

As common in water-absorbing polymers and, inter alia, in DE 10 2004 005 417 A1 described in paragraph [0055], the water-absorbing polymer structures according to the invention can have particles with sizes that lie over the entire range of a particle size section. In some cases, smaller amounts are also outside the range of 150 to 850 microns. Thus, particle size ranges of 10 to 1200 .mu.m or 40 to 1000 .mu.m or even 45 to 850 .mu.m and also 100 to 800 .mu.m and 100 to 700 .mu.m have been observed. For these particle size ranges in a polymer structure according to the invention, the same applies to D1 and D2.

a Contribution to the solution The above-mentioned objects also provide a water-absorbing polymer structure, which is obtainable by the method described above, wherein the water-absorbing polymer structure has an interior area and an outdoor area surrounding the interior, and wherein outside of the water-absorbing polymer structure, the salt comprising two or more Cation of a metal and the at least one organic base as Anion is present.

• – einen gemäß der hierin beschriebenen Testmethode bestimmte Saline Flow Conductivity (SFC) von mindestens 30 × 10^–7 cm³s/g, vorzugsweise von mindestens 50 × 10^–7 cm³s/g, darüber hinaus bevorzugt von mindestens 70 × 10^–7 cm³s/g und am meisten bevorzugt von mindestens 90 × 10^–7 cm³s/g, ferner bevorzugt ein SFC-Wert von mindestens 130 × 10^–7 cm³s/g und besonders bevorzugt von mindestens 155 × 10^–7 cm³s/g, sowie
• – eine nach ERT 442.2-02 bestimmte Absorption unter einem Druck (AAP) von 0,7 psi von mindestens 20 g/g, besonders bevorzugt von mindestens 22 g/g, darüber hinaus bevorzugt von mindestens 24 g/g und am meisten bevorzugt von mindestens 26 g/g, ferner bevorzugt von mindestens 27 g/g;

aufweist.A further contribution to the solution of the abovementioned objects is provided by a water-absorbing polymer structure comprising an inner area and an outer area surrounding the inner area, wherein a salt comprising a divalent or higher cation of a metal and at least one organic base as anion is present in the outer area of the water-absorbing polymer structure and wherein the water-absorbing polymer structure

• - a test method described herein certain Saline Flow Conductivity (SFC) of at least 30 × 10 ^-7 cm ³ s / g, preferably of at least 50 × 10 ^-7 cm ³ s / g, more preferably of at least 70 × 10 ^{- 7} cm ³ s / g, and most preferably at least 90 × 10 ^-7 cm ³ s / g, furthermore preferably an SFC value of at least 130 × 10 ^-7 cm ³ s / g and particularly preferably of at least 155 × 10 ^{5 7} cm ³ s / g, as well
• An absorbance under pressure (AAP) of at least 20 g / g, more preferably of at least 22 g / g, more preferably of at least 24 g / g, and most preferably of (AAP) determined according to ERT 442.2-02 at least 26 g / g, further preferably at least 27 g / g;

having.

It is also possible to limit the properties such as SFC, AAP and CRC upwards. Such upper limits are for the SFC in some cases 180 × 10 ^-7 cm ³ s / g or first 200 × 10 ^-7 cm ³ s / g and sometimes 250 × 10 ^-7 cm ³ s / g or 350 × 10 ^-7 cm ³ s / g or even at 500 × 10 ^-7 cm ³ s / g. Upper limits for the AAP are 30 g / g in some cases 35 g / g and occasionally 45 g / g. Upper limits for the CRC are at 35 g / g in some cases 45 g / g and occasionally 50 g / g.

When Salt or salts comprising a divalent or higher valent cation of a metal and at least one organic base as an anion are those Salts, cations and anions are preferred, which are already related in the beginning with the method according to the invention have been called.

Farther For example, it is preferable that the water-absorbent polymer structure is too at least 50% by weight, preferably at least 70% by weight and beyond preferably at least 90% by weight of carboxylic acid group-carrying monomers based, these carrying carboxylic acid groups Monomers at least 50 wt .-%, preferably at least 70th Wt .-% of acrylic acid consist, preferably at least 20 mol%, more preferably to at least 50 mol% and above Moreover, it is preferably neutralized in a range of 60 to 85% by mole is.

Farther are the water-absorbing according to the invention Polymer structure preferably characterized in that the outdoor area the water-absorbing polymer structure has a higher degree of crosslinking as the inner region of the water-absorbing polymer structures.

According to the invention preferred water-absorbing polymer structures are fibers, foams or Particles, with fibers and particles being preferred and particles being particularly are preferred.

According to the invention preferred Polymer fibers are sized to be in or as yarns for textiles and can also be incorporated directly into textiles. It is preferred according to the invention, that the polymer fibers have a length in the range of 1 to 500 mm, preferably 2 to 500 mm and especially preferably 5 to 100 mm and a diameter in the range of 1 to 200 denier, preferably 3 to 100 denier and more preferably 5 own up to 60 deniers.

According to the invention preferred Polymer particles are sized to have an average particle size according to ERT 420.2-02 in the range of 10 to 3000 μm, preferably 20 to 2000 microns and more preferably 150 to 850 μm or 150 to 600 μm. It is particularly preferred that the proportion of the polymer particles with a particle size in one Range of 300 to 600 microns at least 30% by weight, more preferably at least 40% by weight, and most preferably at least 50% by weight, based on the total weight the postcrosslinked, water-absorbing polymer particles is.

a further contribution to the solution The above-mentioned tasks are performed by a network comprising the previously defined water-absorbing polymer structures or by obtain the inventive method water-absorbing polymer structures and a substrate. Preferably are the water-absorbing invention Polymer structure and the substrate firmly connected. When Substrates are films of polymers, such as polyethylene, Polypropylene or polyamide, metals, nonwovens, fluff, tissues, fabrics, natural or synthetic fibers, or other foams. Furthermore, can the composite according to the invention in addition to the water-absorbing invention Polymer and the substrate also aids such as include thermoplastic materials.

According to one preferred embodiment of the composite according to the invention If the composite is a suction layer, a core or around a wipe.

According to the invention, particularly preferred absorbent layers are those absorbent layers which are in the US 5,599,335 be described as "absorbent members", wherein the US 5,599,335 hereby incorporated by reference and the disclosure of the US 5,599,335 in particular with regard to the fibers and auxiliaries contained in the absorbent layers and with regard to the methods for producing the absorbent layers is part of the disclosure of the present invention.

According to a preferred embodiment of the composite according to the invention, preferably the absorbent layer according to the invention this composite or this absorbent layer comprises at least one region which the inventive water-absorbing polymer structure in an amount in the range of about 15 to 100 wt .-%, preferably about 30 to 100 wt. -%, more preferably from about 50 to 99.99 wt .-%, further preferably from about 60 to 99.99 wt .-% and more preferably from about 70 to 99 wt .-%, respectively based on the total weight of the respective region of the composite or the absorbent layer, said region preferably having a size of at least 0.01 cm ³ , preferably at least 0.1 cm ³ and most preferably at least 0.5 cm ³ .

Furthermore, the absorbent layer according to the invention is preferably preferred by a basis weight of at least 0.02 g / cm ² , preferably of at least 0.03 g / cm ² , more preferably in the range of 0.02 to 0.12 g / cm ² and beyond in the range of 0.03 to 0.11 g / cm ² , wherein the suction layer further has a thickness of at most about 20 mm, preferably at most 15 mm and most preferably at most 10 mm.

According to a preferred embodiment of the absorbent layer according to the invention, this has an area of at most about 500 cm ² , preferably at most about 350 cm ² , more preferably at most about 300 cm ² .

The Production of the composite according to the invention preferably takes place in that the water-absorbing Polymer structures or obtainable by the process according to the invention water-absorbing polymer structures and the substrate and possibly the Aids are brought into contact with each other. That in contact preferably takes place by wet-laid and air-laid methods, Compacting, Extruding and Mixing.

• A) Bereitstellen eines Substrates;
• B) Bereitstellen eines unbehandelten, vorzugsweise jedoch bereits oberflächennachvernetzten, wasserabsorbierenden Polymergebildes;
• C) Bereitstellen einer Feinstteilchenkomponente;
• D) In Kontakt bringen des Substrates mit dem wasserabsorbierenden Polymergebilde;
• E) in Kontakt bringen des wasserabsorbierenden Polymergebildes mit der Feinstteilchenkomponente;
• F) Immobilisieren mindestens eines Teils der Feinstteilchen auf der Oberfläche der wasserabsorbierenden Polymergebilde.

According to a particular embodiment of the method according to the invention for producing a composite, this method comprises the following method steps:

• A) providing a substrate;
• B) providing an untreated, but preferably already surface-postcrosslinked, water-absorbing polymer structure;
• C) providing a fines particle component;
• D) contacting the substrate with the water-absorbent polymer structure;
• E) contacting the water-absorbing polymer structure with the ultrafine particle component;
• F) Immobilizing at least a portion of the fines on the surface of the water-absorbing polymer structures.

When Feinstteilchenkomponente is the Feinstteilchenkomponente preferably already mentioned above in connection with that particular embodiment the method according to the invention for the production of water-absorbing polymer structure, in which a powdery Salt is described as preferred Feinstteilchenkomponente described has been. Particularly preferred is a mixture of powdered salt and powdery Binder.

According to one Variant of this particular embodiment of the method according to the invention For the production of a composite, the substrate and the untreated, but preferably already surface-postcrosslinked, water-absorbing Polymer structures brought into contact, preferably thereby, that first submitted the substrate and then the polymer structure either evenly or but applied to certain areas of the substrate surface, preferably is scattered. Subsequently are then the water-absorbing on the substrate surface Polymer structure brought into contact with the ultrafine particle component, for example, by the Feinstteilchenkomponente on the on the substrate surfaces scattered polymer structure is scattered. Finally done the immobilization of the Feinstteilchenkomponente on the surface of Polymer structures, said immobilization preferably by the above in connection with the method according to the invention for the treatment the surface water-absorbing polymer structure described heating takes place. In this variant of the particular embodiment of the method according to the invention For the production of a composite, therefore, the process step E) after process step D).

According to another variant of this particular embodiment of the method according to the invention for producing a composite, the substrate is initially introduced. Subsequently, the untreated, but preferably already surface-postcrosslinked, water-absorbing polymer structure is brought into contact with the substrate, preferably by initially introducing the substrate and then applying the polymer structure either uniformly or over certain areas of the substrate surface, preferably by scattering. Even before the polymer structure is brought into contact with the substrate surface, the water-absorbing polymer structures are brought into contact with the ultrafine particle component, for example by mixing the ultrafine particle component with the polymer structure before it is scattered onto the substrate surface. After the polymer structures with the substrate in contact were then brought, then the immobilization of Feinstteilchenkomponente on the surface of the polymer structures. In this variant of the particular embodiment of the method according to the invention for the production of a composite, therefore, the method step E) takes place before the method step D).

The The present invention also relates to that described above Process obtainable composite.

Further The present invention relates to chemical products the polymer structures of the invention or the composite. Preferred chemical products are foams, shaped bodies, fibers, Films, films, cables, sealing materials, liquid-absorbent hygiene articles, carrier for plant or fungi growth regulators or crop protection agents, additions for building materials, Packaging materials or floor additives.

It also concerns the invention the use of the water-absorbing polymer structures according to the invention, the by the inventive method available water-absorbing polymer structure, the composite or the by the above-described method obtainable composite in the above mentioned chemical products, in particular in hygiene products, for the fight against flooding, Insulation against water, to regulate the water balance of Floors or for the treatment of food.

The Invention will now be based on figures, test methods and non-limiting Examples explained in more detail.

TEST METHODS

DETERMINATION OF SFC VALUE

wobei

F_S(t = 0)

die die Fließrate in g/s,

L_o

die Dicke der Gelschicht in cm,

r

die Dichte der NaCl-Lösung (1,003 g/cm³),

A

die Fläche der Oberseite der Gelschicht im Messzylinder (28,27 cm²),

ΔP

der hydrostatische Druck, der auf der Gelschicht lastet (4.920 dyne/cm²), und

K

der SFC-Wert ist.

The determination of the permeability in the swollen state (Saline Flow Conductivity = SFC) takes place according to an in WO 95/22356 described method. In a cylinder with a sieve bottom, approx. 0.9 g of superabsorber material (in the case of particles, the entire particle fraction) is weighed in and carefully distributed on the sieve surface. The superabsorbent material is allowed to swell in JAYCO synthetic urine for 1 hour at a pressure of 0.7 psi. After detecting the swelling height of the superabsorber, at a constant hydrostatic pressure, 0.118 M NaCl solution from a leveled storage vessel is passed through the swollen gel layer. The swollen gel layer is covered during the measurement with a special screen cylinder, which ensures a uniform distribution of the 0.118 M NaCl solution above the gel and constant conditions (measurement temperature 20-25 ° C) during the measurement with respect to the gel bed nature. The pressure acting on the swollen superabsorber is still 0.7 psi. Using a computer and a balance, the amount of fluid that passes through the gel layer as a function of time is recorded at 20-second intervals over a 10-minute period. The flow rate g / s through the swollen gel layer is determined by regression analysis with extrapolation of the slope and determination of the center point to the time t = 0 of the flow rate within minutes 2-10. The SFC value (K) was given in cm ³ · s · g ^-1 and calculated as follows:

in which

F _S (t = 0)

the flow rate in g / s,

L _o

the thickness of the gel layer in cm,

r

the density of the NaCl solution (1.003 g / cm ³ ),

A

the area of the top of the gel layer in the measuring cylinder (28.27 cm ² ),

.DELTA.P

the hydrostatic pressure, which rests on the gel layer (4,920 dyne / cm ² ), and

K

the SFC value is.

DETERMINATION OF RETENTION

The retention referred to as CRC is determined according to ERT 441.2-02, where "ERT" is for "EDANA recommended Test "and" EDANA "for European Disposables and Nonwovens Association "stands.

DETERMINATION OF ABSORPTION VACUUM

The as AAP becomes an absorption against a pressure of 0.7 psi determined according to ERT 442.2-02.

DETERMINATION OF PARTICLE SIZE

The Particle sizes are in the present case according to ERT 420.2-02, with the sieves indicated here be used.

EXAMPLES

A. PREPARATION OF SAP PARTICLES

A monomer solution consisting of 640 g of acrylic acid, which was neutralized to 75 mol% with sodium hydroxide solution (532.82 g of 50% NaOH), 801.32 g of water, 1.016 g of polyethylene glycol 300 diacrylate, 2.073 g of monoallyl polyethylene glycol-450 monoacrylic acid ester is freed of dissolved oxygen by purging with nitrogen and cooled to the starting temperature of 4 ° C. After reaching the starting temperature, the initiator solution (0.6 g of sodium peroxydisulfate in 10 g of H ₂ O, 0.014 g of 35% hydrogen peroxide solution in 10 g of H ₂ O and 0.03 g of ascorbic acid in 2 g of H ₂ O) was added. After the final temperature of about 100 ° C was reached, the resulting gel was crushed with a meat grinder and dried at 150 ° C for 2 hours in a drying oven. The dried polymer was crushed roughly, ground by means of a cutting mill SM 100 with a 2 mm Konidurlochung and sieved to a powder having a particle size of 150 to 850 microns and thus powder A obtained (particle sizes: to 150 microns mesh 13%, to 300 microns 15% mesh, 13% mesh at 400 μm mesh, 15% mesh at 500 μm, 20% mesh at 600 μm mesh, 24% mesh at 710 to 850 μm mesh). The properties of this powder are given in Table 1.

COMPARATIVE EXAMPLE 1 (Conventional surface modification with postcrosslinker and aluminum sulphate)

100 g of the powder A are mixed with a solution consisting of 1.0 g of ethylene carbonate (EC), 0.6 g of Al ₂ (SO ₄ ) ₃ × 14 H ₂ O and 3 g of deionized water, the solution being mixed with a syringe a 0.45 mm cannula was applied to the located in a mixer polymer powder. Subsequently, the coated with the aqueous solution powder A was heated in a convection oven at 185 ° C for 30 minutes. A powder A1 was obtained (particle sizes: 150 μm mesh size 13%, 300 μm mesh size 15%, mesh size 400 μm at 400 μm, 15% mesh at 500 μm, 20% mesh at 600 μm mesh, 710 to 850 μm mesh size 25%). The properties of this powder are given in Table 1.

EXAMPLE 1 (Surface modification according to the invention with solution from postcrosslinker and aluminum lactate)

100 g of the powder A are mixed with a solution consisting of 1.0 g of ethylene carbonate, 0.6 g of aluminum lactate and 3 g of deionized water are mixed, wherein the solution by means of a syringe with a 0.45 mm cannula on it in a mixer located polymer powder was applied. Subsequently was that with the watery solution Coated powder A in a convection oven at 185 ° C for 30 minutes heated. A powder A2 was obtained (particle sizes: 150 μm mesh size 12%, to 300 μm Mesh size 16%, to 400 μm Mesh size 14%, to 500 μm Mesh size 14%, to 600 μm Mesh size 21%, to 710 to 850 μm mesh size 23%). The properties of this powder are given in Table 1.

Example 2 (surface modification according to the invention with post-crosslinker and aluminum lactate before post-crosslinking)

100 g of powder A, 0.6 g of aluminum lactate powder (grain size: 85%) in the range of 45 to 150 μm,> 150 μm 9%, <45 μm 6%) over 10 minutes intimately mixed and with a solution consisting of 1.0 g of ethylene carbonate, and 3 g of deionized water mixed, the solution by means of a syringe with a 0.45 mm cannula on it in a mixer located polymer powder was applied. Subsequently was that with the watery solution coated powder A in a convection oven at 185 ° C for 30 minutes. A powder A3 was obtained (particle sizes: 150 μm mesh size 14%, to 300 μm Mesh size 14%, to 400 μm Mesh size 13%, to 500 μm Mesh size 15%, to 600 μm Mesh size 19%, to 710 to 850 μm mesh size 25%).

Example 3 (surface modification according to the invention with postcrosslinker and aluminum lactate after postcrosslinking)

100 g of the powder A are mixed with a solution consisting of 1.0 g of ethylene carbonate, and 3 g of deionized water, the solution by means of a syringe with a 0.45 mm cannula on it in a mixer located polymer powder was applied. Subsequently was that with the watery solution Coated powder A in a convection oven at 185 ° C for 30 minutes heated. Subsequently this product was 0.6 g aluminum lactate powder (grain size: 85%) in the range of 45 to 150 μm,> 150 μm 9%, <45 μm 6%) over 10 minutes intimately mixed. It was obtained a powder A4 (particle sizes: on 150 μm mesh size 15%, to 300 μm Mesh size 14%, to 400 μm Mesh size 13%, to 500 μm Mesh size 14%, to 600 μm Mesh size 19%, to 710 to 850 μm mesh size 25%).

Example 4 (surface modification according to the invention with postcrosslinker and aluminum lactate after post-crosslinking liquid)

100 g of the powder A are mixed with a solution consisting of 1.0 g of ethylene carbonate, and 3 g of deionized water, the solution by means of a syringe with a 0.45 mm cannula on it in a mixer located polymer powder was applied. Subsequently was that with the watery solution Coated powder A in a convection oven at 170 ° C for 30 minutes heated. Subsequently This product came with a solution from 0.6 g of aluminum lactate in 3 g of deionized water over 30 minutes Carefully mixed thoroughly into powder. This mixture product was at 130 ° C for 30 Minutes dried to obtain powder A5 (particle sizes: on 150 μm mesh size 12%, to 300 μm Mesh size 15%, to 400 μm Mesh size 14%, to 500 μm Mesh size 15%, to 600 μm Mesh size 18%, to 710 to 850 μm mesh size 26%).

Example 5 (Surface modification according to the invention with solution from postcrosslinker aluminum lactate and sulfate)

100 g of the powder A are mixed with a solution consisting of 1.0 g of ethylene carbonate, 0.2 g of aluminum lactate, 0.4 g of aluminum sulfate and 3 g of deionized Water mixed, the solution by means of a syringe with a 0.45 mm cannula on it in a mixer located polymer powder was applied. Subsequently was that with the watery solution Coated powder A in a convection oven at 185 ° C for 30 minutes heated. A powder A6 was obtained (particle sizes: 150 μm mesh size 12%, on 300 μm mesh size 15%, to 400 microns Mesh size 14%, to 500 μm Mesh size 15%, to 600 μm Mesh size 20%, to 710 to 850 μm mesh size 24%). The properties of this powder are given in Table 1.

EXAMPLE 6 (Surface modification according to the invention with solution from postcrosslinker aluminum lactate and sulfate)

• * bei 0,3 psi bestimmt.
• ** [× 10^–7 cm³s/g]

100 g of the powder A are mixed with a solution consisting of 1.0 g of ethylene carbonate, 0.3 g of aluminum lactate, 0.3 g of aluminum sulfate and 3 g of deionized water, the solution by means of a syringe with a 0.45 mm cannula on the polymer powder contained in a mixer was applied. Subsequently, the powder A coated with the aqueous solution was heated in a convection oven at 190 ° C. for 30 minutes. A powder A7 was obtained (particle sizes: at 150 μm mesh size 12%, at 300 μm mesh size 15%, at 400 μm mesh size 13%, at 500 μm mesh size 15%, at 600 μm mesh size 20%, at mesh size 710 to 850 μm 25%). The properties of this powder are given in Table 1. Table 1 powder Coating with properties EC [% by weight] Al sulfate [% by weight] Al-lactate [% by weight] CRC [g / g] AAP _{(0.7 psi)} [g / g] SFC ** A 0 0 0 33.8 20 * A1 1.0 0.6 0 29.6 23.7 54 A2 1.0 0 0.6 29.7 25.3 74 A6 1.0 0.4 0.2 28.9 24.0 101 A7 1.0 0.3 0.3 28.2 24.6 110

• * determined at 0.3 psi.
• ** [× 10 ^-7 cm ³ s / g]

B. MANUFACTURE OF SAP PARTICLES

A monomer solution consisting of 260 g of acrylic acid, which was neutralized to 70 mol% with sodium hydroxide solution (202.054 g of 50% NaOH), 505.899 g of water, 0.409 g of polyethylene glycol 300 diacrylate, 1.253 g of monoallylpolyethylene glycol-450 monoacrylic acid ester by rinsing with Dissolved nitrogen from the dissolved oxygen and cooled to the starting temperature of 4 ° C. After reaching the starting temperature, the initiator solution (0.3 g of sodium peroxydisulfate in 10 g of H ₂ O, 0.07 g of 35% hydrogen peroxide solution in 10 g of H ₂ O and 0.015 g of ascorbic acid in 2 g of H ₂ O) was added. After the final temperature of about 100 ° C was reached, the resulting gel was crushed with a meat grinder and dried at 150 ° C for 2 hours in a drying oven. The dried polymer was crushed roughly, ground by means of an SM 100 cutting mill with a 2 mm Konidurlochung and sieved on two powders B and C with a particle size of 150 to 850 microns, which have the particle sizes shown in Table 2. Table 2 powder 150 to 250 μm [%] > 250 to 600 μm [%] > 600 to 850 μm [%] B 8th 42 50 C 12.5 75 12.5

COMPARATIVE EXAMPLE 2 (Conventional surface modification with postcrosslinker and aluminum sulphate)

100 g of the powder B are mixed with a solution consisting of 1.0 g of ethylene carbonate (EC), 0.6 g of Al ₂ (SO ₄ ) ₃ × 14 H ₂ O and 3 g of deionized water, the solution being mixed with a syringe a 0.45 mm cannula was applied to the located in a mixer polymer powder. Subsequently, the powder B coated with the aqueous solution was heated in a circulating air oven at 170 ° C. for 90 minutes. A powder B1 was obtained (particle sizes: at 150 μm mesh size 7%, at 250 μm mesh size 43%, at 600 to 850 μm mesh size 50%). The properties of this powder are given in Table 3.

COMPARATIVE EXAMPLE 3 (Conventional surface modification with postcrosslinker and aluminum sulphate)

Comparative example 2 was repeated with the difference that instead of powder B the powder C was used. Thus powder C1 was obtained (particle sizes: on 150 μm mesh size 12%, on 250 μm mesh size 75.5%, to 600 to 850 microns Mesh size 12.5%). The properties of this powder are in Table 4 indicated.

EXAMPLE 7 (surface modification according to the invention with solution from postcrosslinker and solid aluminum lactate)

100 g of the powder B are mixed with a solution consisting of 1.0 g of ethylene carbonate, 0.6 g of solid aluminum lactate and 3 g of deionized water, the solution by means of a syringe with a 0.45 mm cannula on which in a mixer located polymer powder was applied. Subsequently For example, the powder B coated with the aqueous solution was heated in a convection oven at 185 ° C. for 30 minutes. A B2 powder was obtained (particle sizes: 9% mesh at 150 μm, 40% mesh at 250 μm, 51% mesh at 600 to 850 μm mesh). The properties of this powder are given in Table 3.

EXAMPLE 8 Surface Modification of the Invention with solution from postcrosslinker and solid aluminum lactate)

example 7 was repeated with the difference that instead of powder B the powder C was used. Thus, powder C2 was obtained (particle sizes: on 150 μm mesh size 11.5%, to 300 microns Mesh size 76%, to 600 to 850 μm mesh size 12.5%). The Properties of this powder are given in Table 4.

EXAMPLE 9 Surface Modification of the Invention with solution from postcrosslinker and aluminum lactate solution)

100 g of powder B are mixed with a first solution consisting of 1.0 g of ethylene carbonate and 1.457 g of deionized water and 0.6 g of aluminum lactate 28% with NaOH stabilized aluminum lactate solution, wherein the solutions by means of a syringe with a 0.45 mm cannula on it in a mixer located polymer powder was applied. For the production The NaOH stabilized aluminum lactate solution is 0.0625 mole (7.38 g) sodium aluminate dissolved in 15 ml of water, followed by 0.0475 mol NaOH (2.5 ml of a 50% aqueous NaOH solution) looking for this solution a mixture of 85% lactic acid, diluted in 20 ml of water, is slowly added until a pH of 4.5 is reached (0.29 mol of lactic acid = 31.0 g). Subsequently that became with the watery solutions Coated powder B in a convection oven at 185 ° C for 30 minutes heated. A powder B3 was obtained (particle sizes: 150 μm mesh size 9%, to 250 microns Mesh size 40%, to 600 to 850 μm mesh size 51%). The properties of this powder are given in Table 3.

EXAMPLE 10 (Surface modification according to the invention with solution from postcrosslinker and aluminum lactate solution)

example 9 was repeated with the difference that instead of powder B the powder C was used. Thus, powder C3 was obtained (particle sizes: on 150 μm mesh size 11.5%, to 250 microns Mesh size 76%, to 600 to 850 μm mesh size 12.5%). The Properties of this powder are given in Table 4.

EXAMPLE 11

100 g of powder B, 0.6 g of aluminum lactate powder (particle size: 85%) in the range of 45 to 150 μm,> 150 μm 9%, <45 μm 6%) over 10 minutes intimately mixed and with a solution consisting of 1.0 g of ethylene carbonate, and 3 g of deionized water mixed, the solution by means of a syringe with a 0.45 mm cannula on it in a mixer located polymer powder was applied. Subsequently was that with the watery solution coated powder A in a convection oven at 170 ° C for 90 minutes. A powder B4 was obtained (particle sizes: 150 μm mesh size 14%, to 300 μm Mesh size 13%, to 400 μm Mesh size 13%, to 500 μm Mesh size 15%, to 600 μm Mesh size 19%, to 710 to 850 μm mesh size 25%).

EXAMPLE 12

• * [× 10^–7 cm³s/g]

Tabelle 4 Pulver Beschichtung mit Eigenschaften EC [Gew.-%] Al-sulfat [Gew.-%] Al-lactat [Gew.-%] CRC [g/g] AAP _{(0,7 psi)} [g/g] SFC* C 0 0 0 30,8 27,5 48 C1 1,0 0,6 0 29,1 24,9 115 C2 1,0 0 0,6 (Feststoff) 28,8 27,6 134 C3 1,0 0 0,6 (Lösung) 29,1 24,9 160

• * [× 10^–7 cm³s/g]

Example 8 was repeated with the difference that, instead of powder B, the powder C was used. Thus, powder C4 was obtained (particle sizes: at 150 μm mesh size 11.5%, at 300 μm mesh size 76%, at 600 μm mesh size 12.5%). Table 3 powder Coating with properties EC [% by weight] Al sulfate [% by weight] Al-lactate. [Wt .-%] CRC [g / g] AAP _{(0.7 psi)} [g / g] SFC * B 0 0 0 30.5 26.2 57 B1 1.0 0.6 0 29.5 25.0 90 B2 1.0 0 0.6 (solid) 29.5 26.8 159 B3 1.0 0 0.6 (solution) 29.1 27.8 160

• * [× 10 ^-7 cm ³ s / g]

Table 4 powder Coating with properties EC [% by weight] Al sulfate [% by weight] Al-lactate [% by weight] CRC [g / g] AAP _{(0.7 psi)} [g / g] SFC * C 0 0 0 30.8 27.5 48 C1 1.0 0.6 0 29.1 24.9 115 C2 1.0 0 0.6 (solid) 28.8 27.6 134 C3 1.0 0 0.6 (solution) 29.1 24.9 160

• * [× 10 ^-7 cm ³ s / g]

Claims (33)

A process for producing a water-absorbing Polymer-shaped, comprising the process steps: i) Provide an untreated, water-absorbing polymer structure; ii) bringing the untreated, water-absorbing polymer structure into contact with a salt comprising a divalent or higher cation of a metal and at least one organic base as anion. The method of claim 1, wherein the divalent or higher valent cation of a metal is an Al ³⁺ cation. The method of claim 1 or 2, wherein the organic Base is a deprotonated mono-, di- or tricarboxylic acid. The method of claim 3, wherein the organic Base a lactate anion is. Method according to one of the preceding claims, wherein the salt includes aluminum lactate. Method according to one of the preceding claims, wherein another anion is present which is different from the organic base is. Method according to one of the preceding claims, wherein the further anion is an inorganic base. The method of claim 7, wherein the inorganic Base is a deprotonated inorganic acid. The method of claim 7 or 8, wherein the inorganic Base a deprotonated acid is that gives off two or more protons. Method according to one of claims 7 to 9, wherein the inorganic Base sulfate anion is. Method according to one of the preceding claims, wherein the untreated, water-absorbing polymer structure in the process step ii) from 0.001 to 10% by weight, based on the weight of the untreated, water-absorbing polymer structure, the salt brought into contact becomes. Method according to one of the preceding claims, wherein bringing the untreated, water-absorbing polymer structure into contact with the salt in process step ii) in the presence of at most 15 Wt .-%, based on the weight of the untreated, water-absorbing Polymeric, a solvent he follows. Method according to one of the preceding claims, wherein the method in addition to the process steps i) and ii) the process step iii) surface postcrosslinking of the water-absorbing polymer structure, and wherein the method step iii) before, during or after the process step ii) can be performed. A water-absorbing polymer structure, available through A method according to any one of claims 1 to 13, wherein the water-absorbing Polymer forms an interior and an interior surrounding outdoors includes and being outdoors of the water-absorbing polymer structure comprises a salt two or more Cation of a metal and at least one organic base as anion is available. A water-absorbing polymer structure comprising an interior and an exterior area surrounding the interior. The water-absorptive polymer structure of claim 15, to greater than 80% by weight, based on the water-absorbing polymer structure, of in the range of 50 and 85 mole% neutralized acrylic acid, having the following properties: A1 is one described herein Test Method Specific Saline Flow Conductivity (SFC) greater than 115 x 10 ^-7 cm ³ s / g; B1 an absorbance determined according to ERT 442.2-02 against a pressure of 0.7 psi (AAP _0.7 ) greater than 25.9 g / g; C1 a retention (CRC) determined according to ERT 441.2-02 of at least 25 g / g; and D1 has a particle size distribution of at least 80% by weight of the particles of the water-absorbing polymer structure in a particle size range of 150 to 850 μm, at least 5% by weight of the particles of the water-absorbing polymer structure having a particle size in a range of 150 to 250 μm. The water-absorbing polymer structure of claim 15, based on at least 80% by weight, based on the water-absorbing polymer structure, of between 50 and 85% by mole of neutralized acrylic acid, the exterior of the water-absorbent polymer structure comprising a salt containing a divalent or higher cation Metal, wherein the water-absorbing polymer structure has the following properties: A2 has a Saline Flow Conductivity (SFC) of more than 89 × 10 ^-7 cm ³ s / g determined according to the test method described herein; B2 an absorbance determined to ERT 442.2-02 against a pressure of 0.7 psi (AAP _0.7 ) greater than 24.7 g / g; C2 a retention (CRC) determined according to ERT 441.2-02 of at least 25 g / g. The water-absorbing polymer structure according to claim 15, wherein a salt containing a di- or higher-valent cation of a metal and at least one organic base as anion is present in the outer region of the water-absorbing polymer structure, and wherein the water-absorbing polymer structure A3 has a saline flow conductivity determined according to the test method described herein (FIG. SFC) of at least 30 × 10 ^-7 cm ³ s / g, and B3 has an ERT 442.2-02 specific absorption against a pressure of 0.7 psi (AAP) of at least 20 g / g. The water-absorbing polymer structure according to claim 14, 17 or 18, wherein the divalent or higher-valent cation of a metal is an Al ³⁺ cation. The water-absorbing polymer structure after a the claims 14, 18 or 19, wherein the organic base is a deprotonated mono-, Di- or tricarboxylic acid is. The water-absorbing polymer structure according to claim 20, wherein the organic base is a lactate anion. The water-absorbing polymer structure after a the claims 14, 18 to 21, wherein the salt includes aluminum lactate. The water-absorbing polymer structure after a the claims 14, 18 to 22, wherein there is another anion which is derived from the organic base is different. The water-absorbing polymer structure according to claim 23, wherein the further anion is an inorganic base. The water-absorbing polymer structure according to claim 24, wherein the inorganic base is a deprotonated inorganic Acid is. The water-absorbing polymer structure after a Claim 24 or 25 wherein the inorganic base is a deprotonated one Acid is, which gives off two and more protons. The water-absorbing polymer structure after a the claims 24 to 26, wherein the inorganic base is sulfate anion. Composite containing a water-absorbing polymer structure according to one of the claims 14 to 27 and a substrate. Process for the preparation of a composite, wherein a water-absorbing polymer structure according to one of claims 14 to 27 and a substrate and optionally an adjuvant with each other be brought into contact. Composite, available according to a method according to claim 29th foams, Moldings, Fibers, films, films, cables, sealing materials, liquid-absorbent hygiene articles, carrier for plant and fungal growth regulating agents, packaging materials, bottom additives or Building materials, including the water-absorbing polymer structure after one of the claims 14 to 27 or the composite according to claim 28 or 30. Use of the water-absorbing polymer structure according to one of the claims 14 to 27 or the composite according to claim 28 or 30 in foams, moldings, fibers, Films, films, cables, sealing materials, liquid-absorbent hygiene articles, carriers for plant and fungal growth regulating agents, packaging materials, soil additives, for controlled release of active substances or in building materials. Use of a salt comprising a two- or higher quality Cation of a metal and at least one organic base as anion for the treatment of the surface water-absorbing polymer structure.