US 20140257223A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2014/0257223 A1 Henn et al. (43) Pub. Date: Sep. 11, 2014

(54) SUPER-ABSORBNG WITH Publication Classification RAPIDABSORPTION PROPERTIES AND METHOD FOR PRODUCING THE SAME (51) Int. Cl. A6IL I5/24 (2006.01) (71) Applicant: EVONIK DEGUSSA GMBH, Essen A6IL 5/42 (2006.01) (DE) A6IL 5/60 (2006.01) (52) U.S. Cl. (72) Inventors: Markus Henn, Gelsenkirchen (DE); CPC ...... A61L 15/24 (2013.01); A61L 15/60 Laurent Wattebled, Dusseldorf (DE): (2013.01); A61L 15/425 (2013.01) Peter Herbe, Kevelaer (DE); Jorg USPC ...... 604/370; 604/372:521/149; 156/60 Harren, Baesweiler (DE); Christoph Loick, Tonisvorst (DE) (57) ABSTRACT The present invention relates to a particulate absorbent poly mer material having: (73) Assignee: EVONIK DEGUSSA GMBH, Essen i) a maximum APCo values 1.6) for at least one number (DE) iselected from the group of integers from 2 to 12 (=APC (21) Appl. No.: 14/352,171 ii) a values 12 for the sum total of all APC values for all numbers i from the group of integers from 2 to 12 (=APC (22) PCT Fled: Nov. 12, 2012 sum); (86) PCT NO.: PCT/EP2012/072360 wherein the APCo value is: S371 (c)(1), APC-10s.-QI. Io evalue'xPI, lose-value (2), (4) Date: Apr. 16, 2014 where the QIo value is the Swell index and ix10 seconds after (30) Foreign Application Priority Data adding the 0.9% by weight NaCl solution, and the PI.ix1O see value is the permeability index and ix10 sec Nov. 17, 2011 (DE) ...... 102O11086522.5 onds after adding the 0.9% by weight NaCl solution.

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SUPER-ABSORBING POLYMERS WITH same time the amount of unbound urine in the diaper is RAPIDABSORPTION PROPERTIES AND minimized. Advantageous Superabsorbents also have good METHOD FOR PRODUCING THE SAME transfer properties and so ensure optimum utilization of the 0001. The invention relates to a particulate absorbent entire hygiene article. material, a process for producing aparticulate absor 0006. However, prior art superabsorbents are insuffi bent polymer material, an absorbent core containing a par ciently suitable for use in the above-described new generation ticulate absorbent polymer material, a hygiene article, a pro of cellulose-free diaper designs. cess for producing an absorbent core and also an absorbent 0007. The problem addressed by the present invention was core obtainable by this process. therefore that of overcoming the superabsorbent-related dis 0002 Superabsorbents are -insoluble, crosslinked advantages that Surrender to the prior art. polymers capable of imbibing and retaining, under pressure, 0008 More particularly, the problem addressed by the large amounts of aqueous fluids, especially bodily fluids, present invention was that of providing Superabsorbents that preferably urine or blood, by Swelling and forming hydrogels. are particularly advantageous for use in absorbent cores hav In general, these imbibitions of fluid amount to not less than ing a low cellulose fiber content, for example in the cellulose 10 times or even not less than 100 times the dry weight of the free designs described in WO-A-2008/155722, WO-A-2008/ Superabsorbents, or Superabsorbent compositions, for water. 155711, WO-A-2008/155710, WO-A-2008/155702, WO-A- Owing to these characteristic properties, these polymers have 2008/1557O1 or WO-A-2008/155699. their main application in the absorbent cores of hygiene 0009. Another problem addressed by the present invention articles Such as baby diapers, incontinence products or sani was that of providing a selection process for selecting, from tary napkins. A comprehensive overview of Superabsorbents the multiplicity of currently known superabsorbent materials, and Superabsorbent compositions, their use and their produc those superabsorbents capable of being reliably used in the tion is provided by F. L. Buchholz and A.T. Graham (editors) cellulose-free designs described in WO-A-2008/155722, in “Modern Superabsorbent Polymer Technology'. Wiley WO-A-2008/155711, WO-A-2008/155710, WO-A-2008/ VCH, New York, 1998. 155702, WO-A-2008/155701 or WO-A-2008/155699 for 0003 Superabsorbents are generally prepared by free example. radical polymerization of acid-functional, usually partially 0010. A contribution to solving the problems defined at neutralized monomers in the presence of crosslinkers. By the beginning is made by a particulate absorbent polymer varying the monomer composition, the crosslinkers and also material having at least one of the following properties: the polymerization conditions and the processing conditions 0011 i) a maximum APC values 1.6, preferably 2.0 for the hydrogel obtained after polymerization, polymers and more preferably c2.4 for at least one numberi selected having different absorption properties can be prepared. Fur from the group of integers from 2 to 12 (APC value), ther possibilities are offered by the production of graft poly wherein an APC value of preferably 14.0, more prefer mers for example by using chemically modified Starch, cel ably 12.0 and most preferably 10.0 is not exceeded; lulose and polyvinyl alcohol as described in DE-A-26 12846. 0012 ii) a value a 12, preferably 18 and more preferably 0004. The current trendin diaper construction in particular 224 for the Sum total of all APCo values for all num is to produce ever thinner absorbent cores having a reduced bers i from the group of integers from 2 to 12 (=APC): cellulose fiber content and an increased Superabsorbent con wherein an APC, value of preferably 55, more preferably tent. The advantage of thinner designs manifests itself not 50 and most preferably 45 is not exceeded; only in an improved wearing comfort, but also in reduced wherein the APC. value is defined as follows: costs for packaging and stockholding. The latest generation ix1O see of absorbent cores, which is described for example in WO-A- APC. Iose-QI. Io evalue 2 xPI, lose-value 2008/155722, WO-A-2008/155711, WO-A-2008/155710, where WO-A-2008/155702, WO-A-2008/155701, WO-A-2008/ 155699, EP-A-1 225 857, WO-A-01/15647, WO-A-2011/ 0013 the QI value is the value of the Swell index 120504, DE-A-10 2009 049 450, WO-A-2008/117109, determined as per the herein described test method ix10 WO-A-97/11659, EP-A-0 826 349, WO-A-98/37846, seconds after adding the 0.9% by weight NaCl solution, WO-A-95/11653, WO-A-95/11651, WO-A-95/11652, and WO-A-95/11654, WO-A-2004/071363 or WO-A-01/89439, 0.014 the PI value is the value of the permeability is essentially cellulose-free (and hence the diapers of this type index determined as per the herein described test method are also referred to as fluffless diapers). Superabsorbent par ix10 seconds after adding the 0.9% by weight NaCl ticle immobilization, effected in cellulose-containing absor Solution. bent cores by the cellulose fibers, can beachieved in this latest 0015. In a particular embodiment of the particulate absor generation of absorbent coresby, for example, thermoplastic bent polymer materials of the present invention, these have a fibers immobilizing the superabsorbent particles on a sub WSP241.3 (test method of the Worldwide Strategic Partners strate surface. EDANA and INDA) centrifuge retention capacity (CRC) of 0005. The trend towards ever thinner diaper designs and not less than 22 g/g, preferably not less than 24 g/g, more the disappearance of the temporary fluid-storing and conduct preferably not less than 26 g/g and most preferably not less ing function of cellulose fibers has resulted in a distinct than 28 g/g. change in the performance profile required of Superabsor 0016. In a further particular embodiment of the particulate bents. What is of decisive importance now is the ability of the absorbent polymer materials of the present invention, these hydrogel to prevent leakage of urine directly in the course of have a WSP242.3 absorption under pressure (AUP) of 0.7 psi micturation. This is achieved by the property of the superab of not less than 16 g/g, preferably not less than 18 g/g, more sorbent/hydrogel whereby the fluid is sufficiently imbibed, preferably not less than 20 g/g and most preferably not less and dispersed in the gel layer, during Swelling while at the than 22 g/g, US 2014/0257223 A1 Sep. 11, 2014

0017 Particulate absorbent polymer materials preferred polymer materials is brought into contact with aluminum according to the present invention are fibers, foams or par salts before, during or after the postcrosslinking. ticles, of which fibers and particles are preferable and par 0027. In process step i) initially an aqueous monomer ticles are more preferable. Solution containing a polymerizable, monoethylenically 0018 Polymer fibers preferred according to the present unsaturated acid-functional monomer (C.1) or a salt thereof, invention are dimensioned Such that they can be incorporated optionally a monoethylenically unsaturated monomer (C2) in or as yarns for textiles and also directly in textiles. It is polymerizable with the monomer (C.1), a blowing or expand preferable according to the present invention for the polymer ing agent (C3) and also at least one crosslinker (C4) is free fibers to have a length in the range from 1 to 500 mm, pref radically polymerized to obtain a polymer gel. The monoet erably from 2 to 500 mm and more preferably from 5 to 100 hylenically unsaturated acid-functional monomers (C.1) may mm and a diameter in the range from 1 to 200 denier, prefer be in a partially or completely, preferably partially, neutral ably from 3 to 100 denier and more preferably from 5 to 60 ized state. Preferably, the monoethylenically unsaturated denier. acid-functional monomers (C.1) are in a neutralized State to an 0019 Particulate absorbent polymer materials preferred extent not less than 25 mol %, more preferably not less than according to the present invention are dimensioned such that 50 mol% and even more preferably to an extent of 50-80 mol they have a WSP220.2 mean particle size in the range from 10 %. The disclosure of DE 195 29 348 A1 in this context is to 3000 um, preferably from 20 to 2000 um and more prefer hereby incorporated herein by reference. Neutralization may ably from 150 to 850 p.m. It is especially preferable here for also be effected partly or wholly after the polymerization. the proportion of polymer particles having a particle size in Neutralization may further be effected using alkali metal the range from 300 to 600 um to amount to not less than 50% hydroxides, alkaline earth metal hydroxides, ammonia and by weight, more preferably not less than 65% by weight and also carbonates and bicarbonates. Any further base capable of most preferably not less than 80% by weight, based on the combining with the acid to form a water-soluble salt is also total weight of water-absorbing polymer particles. conceivable. Mixed neutralization with different bases is also 0020. It is further preferable according to the present conceivable. Preference is given to neutralization with a com invention for the particulate absorbent polymer materials of bination of carbonates and/or bicarbonates (which also act as the present invention to be based on partially neutralized blowing or expanding agents) and alkali metal hydroxides, crosslinked . It is particularly preferable in this more preferably with a combination of sodium carbonate and context for the particulate absorbent polymer materials of the Sodium hydroxide. present invention to be crosslinked polyacrylates with a 0028 Moreover, in the inventive water-absorbing polymer microporous structure which consist of monomers bearing structures, the free acid groups may predominate, such that carboxylate groups to an extent of not less than 50% by this polymer structure has a pH in the acidic range. This acidic weight, preferably not less than 70% by weight and more water-absorbing polymer structure can be at least partly neu preferably not less than 90% by weight, all based on the tralized by a polymer structure with free basic groups, pref weight of the polymer materials. It is further preferable erably amine groups, which is basic compared to the acidic according to the present invention for the particulate absor polymer structure. These polymer structures are referred to in bent polymer materials of the present invention to be based to the literature as “Mixed-Bed Ion-Exchange Absorbent Poly an extent not less than 50% by weight, preferably not less than mers' (MBIEA polymers) and are disclosed, interalia, in WO 70% by weight, both based on the weight of the polymer 99/34843 A1. The disclosure of WO99/34843 A1 is hereby materials, on polymerized acrylic acid which is preferably not incorporated by reference and is therefore considered to form less than 20 mol %, more preferably not less than 50 mol % part of the disclosure. In general, MBIEA polymers constitute and even more preferably from 60 to 85 mol% neutralized. a composition which firstly includes basic polymer structures 0021. The particulate absorbent polymer materials of the which are capable of exchanging anions, and secondly an present invention are preferably obtainable by a process con acidic polymer structure compared to the basic polymer taining the steps of: structure, which is capable of exchanging cations. The basic 0022 i) free-radically polymerizing an aqueous monomer polymer structure has basic groups and is typically obtained Solution containing a polymerizable, monoethylenically by the polymerization of monomers which bear basic groups unsaturated acid-functional monomer (C.1) or salt thereof, or groups which can be converted to basic groups. These optionally a monoethylenically unsaturated monomer (O2) monomers are primarily those which have primary, second polymerizable with the monomer (C.1), a blowing or ary or tertiary amines or the corresponding phosphines or at expanding agent (C3) and also at least one crosslinker (C4) least two of the above functional groups. This group of mono to obtain a hydrogel having a microporous structure; mers includes especially ethyleneamine, allylamine, dially 0023 ii) optionally comminuting the hydrogel having a lamine, 4-aminobutene, alkyloxycyclines, vinylformamide, microporous structure; 5-aminopentene, carbodiimide, formaldacine, melamine and 0024 iii) drying the optionally comminuted hydrogel hav the like, and the secondary or tertiary amine derivatives ing a microporous structure to obtain particulate absorbent thereof polymer materials having a microporous structure; 0029 Preferred monoethylenically unsaturated mono 0025 iv) optionally grinding and screening off the result mers bearing acid groups (C.1) are preferably those com ing particulate absorbent polymer materials having a pounds specified as ethylenically unsaturated monomers microporous structure; bearing acid groups (C.1) in WO 2004/037903 A2, which is 0026 V) surface-postcrosslinking the resulting particulate hereby incorporated by reference and is therefore considered absorbent polymer materials having a microporous struc to be part of the disclosure. Particularly preferred monoeth ture with a crosslinker having two or more functional ylenically unsaturated monomers bearing acid groups (C.1) groups capable of reacting with the acid groups on the are acrylic acid and methacrylic acid, acrylic acid being the surface of the polymer materials, wherein the surface of the most preferred. US 2014/0257223 A1 Sep. 11, 2014

0030 The monoethylenically unsaturated monomers (O2) 0036 Generally, useful hollow bodies include used, which are copolymerizable with the monomers (C.1), 0037 gas-filled microballoons based on thermoplastic may be acrylamides, methacrylamides or vinylamides. Fur or non-thermoplastic polymers, ther preferred co-monomers are especially those which in 0.038 polyelectrolyte multilayer capsules, the bearing monomers (C.1) are preferably those com 0.039 hollow spheres based on thermoplastic or non pounds which in WO 2004/037903 A2 are mentioned as thermoplastic polymers, co-monomers (C2). 0040 microsphere particles based on thermoplastic 0031 Copolymerizable, monoethylenically unsaturated polymers and as available for example under the Surfactants are used as co-monomers (C2) in a special EXPANCEL(R) brand name, or embodiment of a process for producing the particulate absor 0041 hollow body having a shell of polycrystalline alu bent polymer materials of the present invention. These special minum oxide. Surfactants include functional groups that are polymerizable. 0042. Useful crosslinkers (C4) preferably likewise include Preferred chemical structures for these surfactants are those compounds specified in WO 2004/037903 A2 as crosslinkers (C3) Does this enumeration relate to where R' and Rare methyl, ethyl, n-propyl, isopropyl. n-bu WO2004037903? If not, (O4) would be correct. Among these tyl, isobutyl, n-pentyl, 2-methylbutyl, 2,2-dimethylpropyl. crosslinkers, particular preference is given to water-soluble —OH, acetyl orallyl and n is -2 to 20 and m is -2 to 20. EO crosslinkers. The most preferred are N,N'-methylenebisacry and PO are respectively hydrophilic and hydrophobic blocks lamide, di(meth)acrylates, triallylmethy to generate Surfactant properties. Reactive allyl groups are lammonium chloride, tetraallylammonium chloride, and allyl preferred for R1 or R2, since they, in accordance with the nonaethylene glycol acrylate prepared with 9 mol of ethylene present invention, interpolymerize later as acryloyl group and oxide per mole of acrylic acid. are more stable in hydrolysis. The commercial Pluriol A 23 R 0043. In addition to the monomers (C.1) and optionally product used by BASF AG may be mentioned as an example (C2), the blowing or expanding agents (C3) and also the at of Such a copolymerizable Surfactant. least one crosslinker (C4), the monomer Solution may also 0032 Useful blowing or expanding agents (C3) include contain water-soluble polymers (O5). Preferred water more particularly any assistant material known to a person soluble polymers comprise partly or fully hydrolyzed poly skilled in the art which, in the polymerization, favors the vinyl alcohol, polyvinylpyrrolidone, starch or starch deriva formation of Voids, as of pores for example, and hence the tives, polyglycols or polyacrylic acid. The molecular weight formation of a microporous structure in the polymer gel. of these polymers is uncritical provided that they are water Useful blowing agents include more particularly those blow soluble. Preferred water-soluble polymers are starch or starch ing agents disclosed for instance in EP-A-0-644 207 as pre derivatives or polyvinyl alcohol. The water-soluble polymers, ferred blowing agents. Especially blowing agents based on preferably synthetic water-soluble polymers such as polyvi carbonates come into consideration here. On heating, the nyl alcohol, can not only serve as the graft base for the blowing agent releases carbon dioxide which is in a dissolved monomers to be polymerized. It is also conceivable to mix or dispersed state in the carbonate-containing monomer Solu these water-soluble polymers with the polymer gel only after tion. The blowing agent may be any carbonate- or bicarbon the polymerization, or with the already dried, water-absorb ate-containing salt or mixed salt and may comprise carbon ing polymer gel. dioxide as a gas or Solid material sodium carbonate, potas 0044. In addition, the monomer solution may also com sium carbonate, ammonium carbonate, magnesium carbon prise auxiliaries (C6), which auxiliaries include especially the ate or magnesium hydroxycarbonates, calcium carbonate, initiators or complexing agents which may be required for the barium carbonate and bicarbonates and their hydrates or other polymerization, for example EDTA. cations, and also naturally occurring carbonates such as dolo 0045 Useful solvents for the monomer solution include mite and its mixtures. Preferred carbonate blowing agents are water, organic solvents or mixtures of water and organic MgCO (NH4)2CO. NaCO and mixtures thereof. It is fur Solvents, the selection of the solvent depending especially ther preferable in this connection for about 0.05% by weight also on the manner of the polymerization. to about 5.0% by weight of blowing agent to be added based 0046. The relative amount of monomers (C.1) and (C2), of on the weight of the optionally partially neutralized monomer blowing or expanding agents (C3) and also of crosslinkers (C.1) and more preferably based on the optionally partially (C4) and water-soluble polymers (C5) and auxiliaries (C6) in neutralized acrylic acid. It is most preferable for about 0.2% the monomer solution is preferably selected such that the by weight to about 3.0% by weight of blowing agent to be particulate absorbent polymer material having a microporous added. Blowing agents may also be encapsulated, as structure obtained after drying in process step iii) is based described in U.S. Pat. No. 7,163,966 for example. 0047 to an extent of 20 to 99.999% by weight, prefer 0033. In addition to or in lieu of the blowing agents ably to an extent of 55 to 98.99% by weight and more described above, hollow bodies having a shell of organic or preferably to an extent of 70 to 98.79% by weight on the inorganic material can also be added to the monomer Solution monomers (C.1), for the purposes of forming Voids in polymer material, as (0.048 to an extent of 0 to 80% by weight, preferably to described in WO-A-2010/115671. Hollow bodies having a an extent of 0 to 44.99% by weight and more preferably shell of an organic material are preferably hollow bodies to an extent of 0.1 to 44.89% by weight on the monomers selected from the following group: (C2), 0034 hollow bodies having a shell of a polymeric ther 0049 to an extent of 0 to 5% by weight, preferably to an moplastic material; extent of 0.001 to 3% by weight and more preferably to 0035 hollow bodies having a shell of a polymeric, non an extent of 0.01 to 2.5% by weight on the crosslinkers thermoplastic material. (C4), US 2014/0257223 A1 Sep. 11, 2014

0050 to an extent of 0 to 30% by weight, preferably to mers (C5) and auxiliaries (C.6), is dispersed with the aid of an extent of 0 to 5% by weight and more preferably to an protective colloids and/or emulsifiers in a hydrophobic extent of 0.1 to 5% by weight on the water-soluble organic solvent, and the polymerization is initiated by means polymers (C5), of free-radical initiators. The crosslinkers (C4) are either dis 0051 to an extent of 0 to 20% by weight, preferably to Solved in the monomer Solution and are metered in together an extent of 0 to 10% by weight and more preferably to with it, or else are added separately and optionally during the an extent of 0.1 to 8% by weight on the auxiliaries (C.6), polymerization. Optionally, a water-soluble polymer (C5) is and added as a graft base via the monomer Solution, or by direct 0052 to an extent of 0.5 to 25% by weight, preferably to initial charging into the oil phase. Subsequently, the water is an extent of 1 to 10% by weight and more preferably to removed from the mixture as an azeotrope and the polymer is an extent of 3 to 7% by weight on water (C7), filtered off where the sum of the weights (C.1) to (C7) is 100% by weight. 0056. In addition, both in the case of solution polymeriza Optimum values in respect of the concentration especially of tion and in the case of inverse Suspension and emulsion poly the monomers, the blowing or expanding agents, crosslinkers merization, the crosslinking can be effected by copolymer and water-soluble polymers, in the monomer Solution can be ization of the polyfunctional crosslinker (C4) dissolved in the determined by simple preliminary tests or else inferred from monomer Solution and/or by reaction of Suitable crosslinkers the prior art, especially publications U.S. Pat. No. 4.286,082, with functional groups of the polymer during the polymer DE-A-27 06135, U.S. Pat. No. 4,076,663, DE-A-3503 458, ization steps. The processes are described, for example, in DE 4020 780 C1, DE-A-4244 548, DE-A-43 33 056 and publications U.S. Pat. No. 4.340,706, DE-A-37 13 601, DE DE-A-4418 818. For the free-radical polymerization of the A-28 40010 and WO-A-96/05234, the corresponding disclo monomer Solution, useful polymerization processes may in sure of which is hereby incorporated by reference. principle be all of those known to those skilled in the art. For 0057. In process step ii), the hydrogel having a example, mention should be made in this context of Solution microporous structure obtained in process step i) is optionally polymerization, which is preferably effected in kneading comminuted, this comminution being effected especially reactors such as extruders or continuously on a polymeriza when the polymerization is performed by means of a solution tion belt spray polymerization, inverse emulsion polymeriza polymerization. The comminution can be effected by means tion and inverse Suspension polymerization. of comminution apparatus known to those skilled in the art, 0053. The is preferably per for instance a meat grinder. formed in water as the solvent. The solution polymerization 0058. In process step iii), the hydrogel having a can be effected continuously or batch wise. The prior art microporous structure which has optionally been commi discloses abroad spectrum of possible variations with regard nuted beforehand is dried. The hydrogel is preferably dried in to reaction conditions, such as temperatures, type and amount suitable driers or ovens. Examples include rotary tube ovens, of the initiators, and the reaction Solution. Typical processes fluidized bed driers, pan driers, paddle driers or infrared dri are described in the following patents: U.S. Pat. No. 4,286, ers. It is additionally preferred in accordance with the inven 082, DE-A-2706 135A1, U.S. Pat. No. 4,076,663, DE-A-35 tion that the hydrogel is dried in process step iii) down to a 03 458, DE 4020 780 C1, DE-A-4244.548, DE-A-43 33 056, water content of 0.5 to 25% by weight, preferably of 1 to 10% DE-A-44 18818. The disclosures are hereby incorporated by by weight, the drying temperatures typically being within a reference and are therefore considered to form part of the range from 100 to 200° C. disclosure. 0059. In process step iv), the particulate absorbent poly 0054 The polymerization is triggered by an initiator, as is mer materials with a microporous structure which are generally customary. The initiators used to initiate the poly obtained in process step iii), especially when they have been merization may be all initiators which form free radicals obtained by Solution polymerization, can be ground and under the polymerization conditions and are typically used in screened off to the desired particle size specified at the outset. the production of superabsorbents. Initiation of the polymer The dried absorbent polymer materials with a microporous ization by the action of electron beams on the polymerizable structure are preferably ground in Suitable mechanical com aqueous mixture is also possible. The polymerization can, minuting devices, for example a ball mill, while screening off however, also be triggered in the absence of initiators of the can be effected for example by using screens of suitable mesh type mentioned above by the action of high-energy radiation S17C. in the presence of photoinitiators. Polymerization initiators 0060. In process step V), the optionally ground and may be present dissolved or dispersed in the monomer Solu screened-off particulate absorbent polymer materials having tion. Useful initiators include all compounds which decom a microporous structure are surface postcrosslinked with a pose to free radicals and are known to the person skilled in the crosslinker having two or more functional groups capable of art. These include especially those initiators which are reacting with the acid groups on the Surface of the polymer already mentioned in WO-A-2004/037903 as possible initia materials, and the Surface of the polymer materials is brought tors. Particular preference is given to producing the water into contact with aluminum salts, preferably with aluminum absorbing polymer structures using aredox system consisting lactate and/or aluminum Sulphate, before, during or after the of hydrogen peroxide, Sodium peroxodisulphate and ascorbic postcrosslinking. acid. 0061 For surface postcrosslinking, the dried and option 0055 Inverse suspension and emulsion polymerization ally ground and screened-off particulate absorbent polymer can also be employed to produce the inventive particulate materials having a microporous structure, from process steps absorbent polymer materials. In these processes, an aqueous, iii) or iv), or else the undried, but preferably already commi partly neutralized solution of the monomers (C.1) and the nuted hydrogel having a microporous structure, from process blowing or expanding agents (C3) and also optionally con step ii), are brought into contact with a preferably organic, taining the further monomers (C2), the water-soluble poly chemical Surface postcrosslinker. Especially when the post US 2014/0257223 A1 Sep. 11, 2014

crosslinker is not liquid under the postcrosslinking condi 150 to 250° C., such that, preferably as a result of which, the tions, it is preferably contacted with the particulate absorbent outer region of the particles of the polymer material is more polymer material or the polymer gel in the form of a fluid highly crosslinked compared to the inner region (post comprising the postcrosslinker and a solvent. The solvents crosslinking), and, when a hydrogel are used, they are simul used are preferably water, water-miscible organic solvents, taneously also dried. The duration of the heat treatment is for instance methanol, ethanol. 1-propanol. 2-propanol or limited by the risk that the desired profile of properties of the 1-butanol or mixtures of at least two of these solvents, water polymer material is destroyed owing to the action of heat. being the most preferred solvent. It is additionally preferred 0069. Before, during or after the postcrosslinking step, the that the postcrosslinker is present in the fluid in an amount Surface of the polymer materials, or of the hydrogel having a within a range from 5 to 75% by weight, more preferably 10 microporous structure, is brought into contact with aluminum to 50% by weight and most preferably 15 to 40% by weight, salts, preferably with aluminum lactate. It is particularly pref based on the total weight of the fluid. erable for the treatment with the aluminum salts to be carried 0062. The contacting of the particulate absorbent polymer out at the same time as the Surface postcrosslinking step by material having a microporous structure or of the optionally bringing a preferably aqueous solution containing the post comminuted hydrogel having a microporous structure, with crosslinker and also the aluminum salt(s), preferably alumi the fluid containing the postcrosslinker is preferably effected num lactate, into contact with the particulate absorbent poly by thorough mixing of the fluid with the polymer material and mer material having a microporous structure, or with the hydrogel, respectively. hydrogel having a microporous structure, and then heating. 0063 Suitable mixing units for applying the fluid are, for 0070. It is preferable here for the aluminum salts to be example, the Patterson Kelley mixer, DRAIS turbulent mix brought into contact with the polymer material/hydrogel in an ers, Lödige mixers, Ruberg mixers, screw mixers, pan mixers amount ranging from 0.01 to 30% by weight, more preferably and fluidized bed mixers, and also continuous vertical mixers in an amount ranging from 0.1 to 20% by weight and even in which the polymer material is mixed at high frequency by more preferably in an amount ranging from 0.3 to 5% by means of rotating blades (Schugi mixer). weight (if present as hydrate, reckoned on an anhydrous 0064. The particulate absorbent polymer material having a basis), all based on the weight of the particulate absorbent microporous structure, or the hydrogel, is preferably con polymer material having a microporous structure or, respec tacted at postcrosslinking with not more than 20% by weight, tively, of the hydrogel having a microporous structure. more preferably with not more than 15% by weight, even (0071 Preferred aluminum salts are particularly AlClx more preferably with not more than 10% by weight and yet 6H2O, NaAl(SO)x12 H2O, KAl(SO4)x12 H2O or Al even more preferably with not more than 5% by weight of (SO)x14-18 HO, aluminum lactate or else water-insoluble solvent, preferably water. aluminum compounds, for instance aluminum oxides, for 0065. In the case of polymer materials in the form of example Al-O, or aluminates. Particular preference is given preferably spherical particles, it is further preferable accord to using aluminum lactate, aluminum Sulphate or mixtures of ing to the present invention for the contacting to be effected aluminum lactate and aluminum Sulphate. Such that only the outer region but not the inner region of the 0072 A contribution to solving the problems defined at particulate polymer materials is brought into contact with the the beginning is also made by an absorbent core containing fluid and hence the postcrosslinker. an upper Substrate layer, a lower Substrate layer and an 0066 Postcrosslinkers are preferably understood to mean absorption layer arranged between the upper and the lower compounds which have at least two functional groups which Substrate layers, can react with the acid groups on the Surface of the polymer wherein the absorption layer includes a particulate absorbent material in a condensation reaction (condensation polymer material according to the invention and less than 0.1 crosslinkers), in an addition reaction or in a ring-opening g, particularly preferably less than 0.05 g and most preferably reaction. Preferred postcrosslinkers are those specified in less than 0.01 g of cellulose fibers per gram of particulate WO-A-2004/037903 as crosslinkers of crosslinker classes II. absorbent polymer material. 0067. Among these compounds, particularly preferred (0073 “Absorbent core” for the purposes of the present postcrosslinkers are condensation crosslinkers, for example invention is preferably understood as meaning a construction diethylene glycol, triethylene glycol, polyethylene glycol, which in the case of an absorbent article, for instance a diaper, glycerol, polyglycerol, propylene glycol, diethanolamine, tri can be arranged between the upperply, impermeable to aque ethanolamine, polyoxypropylene, oxyethylene-oxypropy ous fluids and facing away from the body side of the wearer, lene block copolymers, Sorbitan fatty acid esters, polyoxy and the lowerply, permeable to aqueous fluids and facing the ethylene Sorbitan fatty acid esters, trimethylolpropane, body side of the wearer, and the primary function of which is pentaerythritol, polyvinyl alcohol, sorbitol, 1,3-dioxolan-2- to absorb and store the fluids, for example blood or urine, one (ethylene carbonate), 4-methyl-1,3-dioxolan-2-one (pro which have been imbibed by the absorbent article. The absor pylene carbonate), 4.5-dimethyl-1,3-dioxolan-2-one, 4.4- bent core itself preferably comprises no imbibition system, no dimethyl-1,3-dioxolan-2-one, 4-ethyl-1,3-dioxolan-2-one, upperply and no lowerply of the absorbent article. 4-hydroxymethyl-1,3-dioxolan-2-one, 1,3-dioxan-2-one, 0074. However, what is most preferable according to the 4-methyl-1,3-dioxan-2-one, 4,6-dimethyl-1,3-dioxan-2-one present invention is for the absorbent core to be essentially and 1,3-dioxolan-2-one. free of cellulose fibers. The formulation “essentially free of 0068. Once the particulate absorbent polymer material cellulose fibers’ is used herein to describe an article, such as having a microporous structure, or the hydrogels having a an absorbent core, which contains less than 10% by weight of microporous structure, have been brought into contact with cellulose fibers, less than 5% by weight of cellulose fibers, the postcrosslinker or with the fluid including the post less than 1% by weight of cellulose fibers, no cellulose fibers crosslinker, they are heated to a temperature in the range from or not more than an insignificant amount of cellulose fibers. 50 to 300° C., preferably 75 to 275° C. and more preferably Cores of this type are more particularly described in WO-A- US 2014/0257223 A1 Sep. 11, 2014

2008/155722, WO-A-2008/155711, WO-A-2008/155710, substrate layer, as shown for instance in FIGS. 3 and 4 of WO-A-2008/155702, WO-A-2008/155701, WO-A-2008/ WO-A-2008/155722. In this case, the layer of thermoplastic 155699, EP-A-1 225 857, WO-A-01/15647, WO-A-2011/ material may be obtainable by melting a fibrous thermoplas 120504, DE-A-10 2009 049 450, WO-A-2008/117109, tic material for example. WO-A-97/11659, EP-A-0 826 349, WO-A-98/37846, 0080 Preferred materials for the upper and lower sub WO-A-95/11653, WO-A-95/11651, WO-A-95/11652, strate layers and also for the thermoplastic material are those WO-A-95/11654, WO-A-2004/071363 or WO-A-01/89439. materials which are described by way of example in WO-A- 0075. In a preferred embodiment of the absorbent core 2008/155722 as materials that are preferred for these compo according to the present invention, the absorbent core con nentS. tains a thermoplastic material and a multiplicity of compart I0081. The manner of producing absorbent cores of this ments containing the particulate absorbent polymer material. type is preferably equal to the manner described by way of Absorbent cores particularly preferred in this context accord example in WO-A-2008/155699. Accordingly, the process ing to the present invention are such constructions as are comprises the steps of called and described as absorbent core in WO-A-2008/ 0082 depositing the particulate absorbent polymer 155722, WO-A-2008/155711, WO-A-2008/155710, WO-A- material on the lower substrate layer in a first pattern to 2008/155702, WO-A-2008/155701 or WO-A-2008/155699. form a first absorbent layer such that the particulate Accordingly, in a particularly preferred embodiment of the absorbent polymer material is discontinuously distrib present invention, the absorbent core contains layers of a thermoplastic material and a multiplicity of compartments uted on the lower substrate layer; containing the particulate absorbent polymer material, 0.083 depositing the particulate absorbent polymer wherein the compartments are each bounded by the upper or material on the upper Substrate layer in a second pattern lower substrate layer and also by a layer of the thermoplastic to form a second absorbent layer such that the particulate material. Such a construction can be realized according to the absorbent polymer material is discontinuously distrib teaching of the above-cited patent applications by the particu uted on the upper Substrate layer, late absorbent polymer material being applied to the particu 0084 depositing the layer of thermoplastic material on lar substrates (upper or lower substrate layer) in clusters of the particulate absorbent polymer material and the lower particles to form a grid pattern forming land areas and junc and upper Substrate layer to cover the particulate absor tion areas between the land areas. “Land areas' are areas in bent polymer material on the lower and upper substrate which the thermoplastic material is not in direct contact with layers; and the upper or lower substrate layer. “Junction areas” are areas 0085 combining the first and second absorbent layers in which the thermoplastic material is in direct contact with together such that at least one portion of the thermoplas the upper or lower substrate layer. The junction areas in the tic material of the first absorbent layer contacts at least grid pattern include little or no particulate absorbent polymer one portion of the thermoplastic material of the second material. The land areas and junction areas can take a multi absorbent layer. tude of forms/shapes which include but are not limited to I0086 A contribution to solving the problems defined at circular, oval, square, rectangular, triangular and the like. the outset is also made by a hygiene article containing an 0076 One example of an absorbent core according to the absorbent core of the present invention, this hygiene article present invention is a core containing a first Sub-layer and a preferably being a diaper. A diaper typically contains a lower second Sub-layer adjoining the first Sub-layer, wherein ply permeable to fluids (which when the diaper is being worn 0077 the first sub-layer contains the upper substrate faces the body side of the diaper wearer), an upperply essen layer and also compartments containing the particulate tially impermeable to fluids (which when the diaper is being absorbent polymer material which are bounded by the worn faces away from the body side of the diaper wearer) and upper Substrate layer and a first layer of a thermoplastic also the absorbent core of the present invention, which is material, and arranged between the lower ply and the upper ply. The 0078 the second sub-layer contains the lower substrate hygiene article in addition to these three components may layer and also compartments containing the particulate also contain further components, for instance a reclosable absorbent polymer material which are bounded by the fastening system as described by way of example in WO-A- lower Substrate layer and a second layer of athermoplas 2008 155699, or a further acquisition layer localized between tic material, the lowerply permeable to fluids and the absorbent core of the wherein the first layer of thermoplastic material adjoins the present invention, as described by way of example in WO-A- second layer of thermoplastic material. This construction cor 2008/155722. A diaper construction preferred according to responds to the construction shown by way of example in the present invention is shown by way of example in FIG. 1 of FIGS. TA and 7B of WO-A-2008/155722. WO-A-2008/155722. 007.9 The thermoplastic material in the preferred design I0087. A contribution to solving the problems defined at of the absorbent core according to the present invention the outset is also made by a process for producing an absor serves primarily to cover and at least partially immobilize the bent core containing an upper Substrate layer, a lower Sub particulate absorbent polymer material on the upper or lower strate layer and also an absorption layer arranged between the Substrate layer. In one embodiment of the present invention, upper and the lower substrate layers, wherein the absorption the thermoplastic material can be in an essentially uniform layer comprises a particulate absorbent polymer material and arrangement within the particulate absorbent polymer mate less than 0.1 g of cellulose fibers per gram of particulate rial between the polymers. However, in one specific embodi absorbent polymer material, ment, the thermoplastic material may be a fiber layer which is containing the steps of at least partly in contact with the particulate absorbent poly I0088 A) providing a particulate absorbent polymer mate mer material and partly in contact with the upper or lower rial according to the invention; US 2014/0257223 A1 Sep. 11, 2014

0089 B) incorporating the particulate absorbent material (0103 FIG. 3 shows the lid 8, which is made of PVC, for in an absorbent core. the measuring pot 6. 0090 Incorporating the particulate material in the absor 0104 FIG. 4 shows the weight 10 which is placed on the bent core comprises for example the process steps of plunger 7. Height and width of the weight 10 depend on the 0091 B1) depositing the particulate absorbent polymer weight of the material used. Total loading due to plunger 7 material on the lower substrate layer in a first pattern to and weight 10 is 594 g5 g (corresponds to a loading of 21 form a first absorbent layer such that the particulate absor g/cmi-0.2 g/cm). The width of the weight should not exceed bent polymer material is discontinuously distributed on the 70 mm. lower substrate layer; 0105 FIG. 5 shows the experimental arrangement 0092 B2) depositing the particulate absorbent polymer involved in determining the APC values. material on the upper Substrate layer in a second pattern to form a second absorbent layer such that the particulate TEST METHODS absorbent polymer material is discontinuously distributed on the upper Substrate layer, Determining the APC Values 0093 B3) depositing the layer of thermoplastic material 0106 APC values were determined using the measuring on the particulate absorbent polymer material and the arrangement shown in FIG. 5. lower and upper substrate layer to cover the particulate absorbent polymer material on the lower and upper sub 1. Principle of Measurement strate layers; and 0094 B4) combining the first and second absorbent layers 0107 To determine the APC values, 1.800 g (+0.005 g) together such that at least one portion of the thermoplastic of the particulate absorbent polymer material to be ana material of the first absorbent layer contacts at least one lyzed (hereinafter referred to as “SAP) are sprinkled portion of the thermoplastic material of the second absor into the measuring pot 6 which is shown in FIG. 1 and bent layer. has a screen fabric as base and uniformly distributed on 0095. A contribution to solving the problems defined at the screen base. The plunger shown in FIG. 2 is then the outset is also made by a process for producing an absor introduced into the measuring pot and, as shown in FIG. 5, loaded with such a weight 10 (see FIG. 4) that a bent core containing an upper Substrate layer, a lower Sub pressure of 21.0 g/cm +0.2 g/cm (total weight of strate layer and also an absorption layer arranged between the plunger and weight=594 g5 g) on the SAP material. upper and the lower substrate layers, wherein the absorption The cylinder unit (measuring pot 6, SAP, plunger 7 and layer comprises a particulate absorbent polymer material and weight 10) is placed on a support table 15 having a less than 0.1 g of cellulose fibers per gram of particulate circularly round cutout, as shown in FIG. 5. The support absorbent polymer material, table 15 stands above a balance 1. A peristaltic pump 11 containing the steps of passes the test Solution into the cylinder unit at constant 0096 a) selecting a suitable particulate absorbent polymer flow rate. Conducted liquid is continually measured in material on the basis of the results of determining the the collecting vessel 13 underneath the support table 15 product of (swell index) and permeability index (APC (on a balance 1). There are outflows A and B in measur value) for at least one time t, after adding a fluid to the ing pot 6 at a previously defined height (the lower out particulate absorbent polymer structure; flow B in the measuring pot 6 shown in FIG. 1 is closed, 0097 b) incorporating a particulate absorbent material as is indicated in FIG. 5). As the gel layer forms, a liquid thus selected in the absorbent core, column can become established up to the height of out wherein preferred constructions for absorbent cores are the flow A. Thereafter, excess liquid exits via the outflow A. constructions already described as preferred at the beginning This liquid passes through a piece of tube 16, about 10 in connection with the absorbent core of the present inven cm in length, into a collecting vessel 14 and is continu tion. ally measured on a balance 2. Throughout the entire 0098. In one preferred embodiment of the process accord measurement, the height of the developing gel layer is ing to the present invention, Stepa) comprises determining the likewise measured continually. All measurements (bal product of swell index and permeability index (APC value) ances, height measurement) are automatically captured for at least 11 different times t, and selecting the particulate and stored. absorbent polymer material on the basis of the sum total of all 0108. When measurement conditions (amount of APC values obtained. weighed-in SAP in g, pressure on SAP in g/cm, feed 0099. A contribution to solving the problems defined at stream of test solution to cylinder unit in g/sec) are the outset is also made by an absorbent core that is obtainable chosen to be constant, the following measurement data by the processes described above. (O1) to (O3) are accordingly continuously captured: 0100. The invention will now be more particularly eluci 0.109 (O1) changing height of developing gel layer by dated by means of figures, test methods and non-limiting height-measuring instrument 3: examples. 0110 (O2) changing weight on balance 1 at left in FIG. 5 due to the test liquid passing through the gel layer, FIGURES 0.111 (O3) changing weightonbalance 2 at right in FIG. 0101 FIG. 1 shows the measuring pot 6 used to determine 5 due to the test liquid exiting via outflow A. the APC values with its particular dimensions (in mm) 0102 FIG. 2 shows the plunger 7 used for determining the 2. Measuring Instruments Used APC values with its particular dimensions (in mm), which is 0112 2 balances (1, 2) with an accuracy of min 0.1 g, inserted into the measuring pot 6 shown in FIG. 1. equipped with a PC interface (e.g. Sartorius CP 8201). US 2014/0257223 A1 Sep. 11, 2014

0113 Height-measuring instrument 3 with an accuracy sible to use either, as far as suitable, the system for of min O1 mm and a measurement length of min. 30 mm, measured value recording, or alternatively the requi equipped with a PC interface (e.g. Tesa Digico 2). site amount can also be determined using a stopwatch 0114 Liquid reservoir 4 (at least corresponding to the and a glass beaker or similar. Standard flow rates are liquid quantity predetermined by the test parameters, for 1 and 2 g/s. example 30 min at 2 g/s=3600 g). I0128. The system for measured value recording is 0115 Test apparatus 5 with loading (see also FIGS. 1 assembled. Any system can be used whereby mea and 2). Surement data from balances and height-measuring 0116 Transparent measuring pot 6 of Plexiglas as per instruments can be recorded under time control. Such FIG. 1, (d1 (Binner)=60.3 mmit0 mm, h=100 mm-0.5 a system can consist for example of a computer with mm) with 2 outflows (of which only the upper one is Windows operating system (XP or later), Microsoft used and the lower is closed during the measurement) in Excel (version 6 or later) an RS232 4-fold interface h1*=55 mm and h2*=83 mm (Binner-10 mm) (*mean card and programmed Visual Basic for Application height of outflows). The lower side of the measuring pot module. The system has to be capable of performing is equipped with a stainless steel screen fabric (400 all 3 measured value retrievals (O1) to (O3) in a time mesh-36 um). window of not more than 0.5 seconds. Balances 1 and 0117 Plastics plunger 7 (d2 (0 outer)=60mm-0mm) of 2 and the height-measuring instrument 3 are con PVC as per FIG. 2 (d1-d2=0.3 mm and h=150 mm) The nected to the computer 12 (the program for measured lower side of plastics plunger 7 is equipped with a stain value recording has to be adjusted to the appropriate less steel screen fabric (400 mesh-36 um). The height of settings (baud rate, parity, etc.) in respect of the bal the lower part of the plastics plunger 7 is 28 mm. There ances 1 and 2 and the height-measuring instrument 3. are 4 struts in this part, which contribute to stabilizing the screen fabric. Each strut is equipped in the lower Measurement: region (i.e. in the region which is in contact with the steel Screen fabric) with an approximately 3x5.5 mm pas 0129. The SAP sample to be analyzed must be thor sageway to ensure uniform distribution of the liquid. oughly commixed. The test material to be removed 0118. A close-fitting lid 8 with cutouts for the plastics should be free of clumps and impurities. 1.800gt0.005 plunger 7 and the liquid feed 9 (see FIG. 3). g of SAP are weighed into the test apparatus. The SAP is 0119 Weight 10, which is placed on the plastics plunger uniformly distributed on the screen base. 7 (see FIG. 4). Plastics plunger 7 and weight 10 together I0130. The SAP sample is loaded at 21.0 g/cm +0.2 have to attain the defined weight. The standard here is a g/cm using the plunger 7 and the weight 10 and placed total mass of 594 g5 g (corresponds to a loading of in the cutout of support table 15. The outflow-equipped about 21 g/cm +0.2 g/cm, which corresponds to a tube end from the peristaltic pump (liquid feed 9) is pressure of about 0.3 psi). placed over a length of 2-3 cm through the addition I0120 Liquid pump 11 (a peristaltic pump for example) aperture in the covering plate 8 of the test apparatus. having a performance of 30 mL/min to 400 mL/min, e.g. 0131 The height-measuring instrument 3 is installed Ismatec MCP standard with Ismatec SB-2V pump head with the measuring rod centered on plunger 7 of the test and Tygon Standard tubing (ID 4.8, WT 1.6, OD 8.0). apparatus. During the test period of 30 minutes, the I0121 Computer system 12 with appropriate software measured values are retrieved every 10 seconds and for recording the balance display & height measure recorded against the particular time. mentS. 0.132 Balances 1 and 2 are tared and the height-mea 0.122 Collecting vessels 13 and 14 for liquid (min. 3.6 Suring instrument 3 is Zeroed. L). 0133. The system for measured value recording is ini I0123 Support table 15 with a circularly round cutout (A tialized. 6 cm, corresponds exactly to the width of the screen 0.134 Directly but in any case not later than 0.5 seconds fabric in the measuring pot). This cutout is Surrounded after initializing the system for measured value record by an approximately 2 cm high plastics ring (07.2 cm, ing the addition via the peristaltic pump 11 is started. corresponds approximately to the outside diameter of 0.135. On conclusion of the test period, the peristaltic the measuring pot) in a centric arrangement (this fixes pump 11 is switched off. the cylinder unit during the measurement in order that the liquid may pass through unhindered and the height 4. Evaluation measurement is always made in the same place). I0136. The data series of height (h) in mm at time (t) in 3. Performing the Measurement S (O1), flow rate (Flth.) in g at time (t) in S (O2) and 0.124. At least one 2-fold determination shall be per overflow (Fl.ov.) in g at time (t) in s (O3) can be used to formed. calculate the following further values (each at time t): (0.125 Preliminary work: 0.137 VZu, ing: liquid volume addition at time t; 0.126 The liquid reservoir 4 is filled to provide suffi I0138 V, in cm: the gel volume at time t (base area of cient test liquid (0.9% NaCl solution). The tempera measuring pot 6–28.27 cm): ture of the test liquid is 23° C.2.0° C. (room tem V, cm =h, mm/10*28.27 cm. formula: perature=23° C.i.2.0° C., relative humidity 55%-15%). I0139 AV, in cm: the gel volume increase within 10 sat I0127. The peristaltic pump 11 is adjusted in accor time t (base area of measuring pot 6–28.27 cm. dance with the intended flow rate. For this it is pos AV, cm)=(h, mm-ho (mm))/10* 28.27 cm formula: US 2014/0257223 A1 Sep. 11, 2014

0140 QI: Swell index (dimensionless) at time t a mincer and dried at 150° C. in a circulating air drying (E-starting weight of SAP in g; 1 cm =1 g is assumed cabinet for 2 h. The dried product is coarsely crushed, ground for a 0.9% NaCl solution): and screened off to a particle size fraction of 150-710 um. The bulk obtained is screened into individual particle size frac QI-AV, (cm/(EIg|*10) formula: tions and mixed together to form a synthetically produced AFI.th., in gs: flow rate averaged over 10s at time t: PSD as follows: AFI.ih.gis=(Fl.ih.g-Fi.ih.og), 10s formula: 0141 Vii, ing: volume supernatant in APC measuring 0145 The intermediates thus obtained are postcrosslinked pot: by coating with a solution consisting of ethylene carbonate/ Vii, cm-g=Vzu, Ig-V, cm F-Flow, g-Flth.,g) formula: water/aluminum lactate/aluminum Sulphate in a ratio of 1/3/ 0.142 h(Vii), in mm: theoretical (calculated) height of 0.4/0.3% based on 100 g of intermediate and subsequent liquid in APC pot (taking into account the area of postheating in a drying cabinet at 170° C., 90 minutes. plunger-5 cm; effective area=28.27 cm-5 cm =23.27 cm): Example 1 h(Vii), (mm)=(h, mm/10+(Vii, (g)/23.27 cm))*10 formula: In Accordance with the Present Invention 0.143 PI: permeability index (dimensionless) at time 0146 In 963.60 g of an aqueous solution of sodium acry t=20 S. . . 120 S: late having a degree of neutralization of 70 mol % (based on acrylic acid) and also a total monomer concentration of 40.30% are dissolved 0.775 g of polyethylene glycol 300 AFlth; (cm/sec x h; (cm) formula P = diacrylate (0.20% based on acrylic acid/ester content=83%) * T 981 (cm/sec.2)x h(Vit), cm x 28.27 cm2: 10° sec and 1.639 g of polyethylene glycol 440 monoallyl ether acry late (0.40% based on acrylic acid/ester content–78%) as crosslinker. This solution is subsequently admixed with 9.6 g. APC,iXIO see : APC,iXIO seevalue at time TF20s... 120 of a 10% aqueous solution of the comonomer Pluriol A 23 R s(i=2 to 12). The (from BASF) and the monomer solution is purged with nitro values described above are further used to determine the gen for 30 minutes in a plastics polymerization vessel to APC value (i.e. highest of the 11 APC values determined), remove the dissolved oxygen. At a temperature of 4°C., 2 g of the APC average value APC and the sum total of all APC slightly calcined sodium carbonate (from Solvay) are added as blowing agent and the polymerization is started by the values (APCsum). successive addition of 0.3 g of sodiumperoxodisulphate in 10 g of distilled water, 0.07 g of 35% hydrogen peroxide solution APCix10 sec = Qii.102 see * Pix10 sec formulae in 10g of distilled water and 0.015 g of ascorbic acid in 2 g of distilled water. On attainment of the final temperature (about 1 2 100° C.) the gel is comminuted with a mincer and dried at APCnear = iX. APCix10 sec 150° C. in a circulating air drying cabinet for 2 h. The dried i=2 product is coarsely crushed, ground and Screened off to a 2 particle size fraction of 150-710 um. The bulk obtained is APC m =X APC-10 cc screened into individual particle size fractions and mixed i=2 together to form a synthetically produced PSD as follows: >150 Im=15%/>300 m=48%/>500 im—32%/>600 Im=5%. EXAMPLES 0147 The intermediates thus obtained are postcrosslinked Comparative Example by coating with a solution consisting of ethylene carbonate/ water/aluminum lactate/aluminum Sulphate in a ratio of 1/3/ Not in Accordance with the Present Invention 0.4/0.3% based on 100 g of intermediate and subsequent 0144. In 1972.90 g of an aqueous solution of sodium acry postheating in a drying cabinet at 170° C., 90 minutes. late having a degree of neutralization of 70 mol % (based on Example 2 acrylic acid) and a total monomer concentration of 39.37% are dissolved 1.770 g of polyethylene glycol 300 diacrylate In Accordance with the Present Invention (0.2% based on acrylic acid/ester content=72%) and 2.560 g of polyethylene glycol 440 monoallyl ether acrylate (0.4% 0.148. In 1962.4 g of an aqueous solution of sodium acry based on acrylic acid/ester content=100%) as crosslinker. The late having a degree of neutralization of 70 mol % (based on monomer Solution is purged with nitrogen for 30 minutes in a acrylic acid) and also a total monomer concentration of plastics polymerization vessel to remove the dissolved oxy 39.6% by weight are dissolved 1.529 g of polyethylene glycol gen. At a temperature of 4°C., the polymerization is started 300 diacrylate (ester content=83.7%; 0.2% by weight based by the successive addition of 0.6 g of sodium peroxodisul on acrylic acid) and 3.303 g of polyethylene glycol 440 phate in 10 g of distilled water, 0.14 g of 35% hydrogen monoallyl ether acrylate (0.40% by weight based on acrylic peroxide solution in 10 g of distilled water and 0.03 g of acid/ester content=77.5%). Thereafter 10.0 g of sodium car ascorbic acid in 2 g of distilled water. On attainment of the bonate produced in the moving bedspray granulation process final temperature (about 100° C.) the gel is comminuted with and having aparticle size of 400-600 um are added as blowing US 2014/0257223 A1 Sep. 11, 2014

agent (0.5% by weight based on batch size). The monomer sis of the polymer from the comparative example are illustra solution is purged with nitrogen for 15-30 minutes to remove tively compiled in Tables 1 and 2. the dissolved oxygen. At a temperature of 20°C., the mono mer Solution, which is admixed with 0.6 g of sodium peroxo TABLE 1 disulphate in 10g of distilled water and 0.14 g of 35% hydro gen peroxide solution in 10g of distilled water, is transferred the directly obtained measurements (O1). (O2) and (O3 into the List Batch CRP 2.5 kneader under inert gas counter Time t ht Time t FI.tht Time t FI.Ow.t current and shaft agitation. The target settings and hence the s mm s g s g desired parameters during the reaction in the twin-shaft, coro O O.OO O O.SO O O.O1 tating batch-operated kneading reactor and/or the peripherals 10 O.28 10 4.65 10 O.O1 are: temperature of oil in heating circuit of reactor shell: 75° 2O 122 2O 15.35 2O O.OO 30 2.15 30 27.77 30 O.OO C.: shaft speed: 60 revolutions perminute. After the monomer 40 2.96 40 41.2O 40 O.OO solution has been transferred into the reactor interior, the 50 3.65 50 55.07 50 O.OO sodium carbonate is added. After it has been stirred in for 30 60 4.27 60 69.8O 60 O.OO seconds, 0.030 g of ascorbic acid in 2 g of distilled water is 70 4.87 70 85.12 70 O.OO 8O 5.41 8O 100.63 8O O.OO introduced into the reaction interior, and the exothermic reac 90 S.92 90 116.13 90 O.O1 tion is started. The target value for the oil in the heating circuit 1OO 6.42 100 13155 100 O.O1 of the reactor shell is set to 100° C. After 5 minutes have 110 6.88 110 147.15 110 O.O2 elapsed, the heating circuit is switched offAfter altogether 10 120 7.31 120 162.88. 120 O.O1 minutes the cororating shafts are stopped, the reactor is TABLE 2 measured quantities obtained arithmetically from the measurements of Table 1 Time DV, DFI.th. Vzu, V, Vi, h(Vi), APC (sec) cm QI, gfs (g) cm (cm (mm) PI, value O O.OO O.OO O.SO O O.O1 O.OO O.OO 10 O.78 O.04 O.42 2O 0.79 14.SS 6.53 6.42 2O 2.67 O.15 1.07 40 3.46 21.19 10.33 45.72 1.01 30 2.62 O.15 1.24 60 6.08. 26.14 13.39 72.03 1.53 40 2.28 O.13 1.34 8O 8.36 30.44 16.04 89.31 1.43 50 1.97 O.11 1.39 1OO 10.33 34.59 18.52 98.69 1.19 60 1.75 O.10 1.47 120 12.08 38.11 20.6S 109.86 1.04 70 1.67 O.09 1.53 140 13.7S 41.12 22.54 119.25 1.03 8O 1.53 O.O8 1.55 160 15.28 44.09 24.35 124.10 O.90 90 1.46 O.O8 1.55 180 16.7S 47.12 26.17 126.36 0.84 1OO 1.39 O.O8 1.55 200 18.14 SO.30 28.03 127.54 0.76 110 1.30 O.O7 1.56 220 19.44 S3.39 29.82 129.SS O.68 120 1.23 O.O7 1.57 240 20.67 S6.45 31.57 131.22 O.61 'as mean value of a fourfold determination opened, the hydrogel formed is removed and dried in a cir TABLE 3 culating air drying cabinet at 150° C. for 2 hours. The dried product is crushed, ground with a cutting mill from Retsch APC parameters of polymers from the comparative example and and a cutting sprocket of 2 mm hole size, screened into Examples 1 and 2 individual particle size fractions and mixed together to form Polymer APC APC CRC Igg AAP bib a synthetic particle size distribution as follows: Comparative 1.53 11.0 example Example 1 7.01 37.3 26.1 25.3 Example 2 3.47 18.9 25.9 25.2 0149 Postcrosslinking is affected by coating with a solu tion consisting of ethylene carbonate/water/aluminum lac tate/aluminum sulphate in a ratio of 1/4/0.4/0.3% based on 100 g of intermediate and also Subsequent postheating in a Example 5 drying cabinet at 175°C., 90 minutes. 0151. The polymers obtained in the comparative example and Examples 1 and 2 are used to produce an absorbent core Example 4 which is in accordance with the present invention. 0150. The polymers obtained in the comparative example 0152 Acut-to-size nonwoven (article No. 00028710 from and in Examples 1 and 2 are measured for the APC value Freudenberg) having the dimensions of 12x12 cm is uni and the APC, value using the test method described herein. formly sprayed with adhesive (Dispomelt CS 22 from Hen The results are shown in Table 3. The measurements obtained kel) using a pneumatic hot-melt adhesive gun from Bihnen, continuously for a period of 120 seconds in the determination type HB 710 spray inc. twist nozzle set standard 0 1.5 mm. of the APC parameters and the measurement data derived operated at 4 bar compressed air, for 30 seconds. The spray therefrom purely arithmetically in respect of the APC analy gun is adjusted beforehand to a melting temperature of 160° US 2014/0257223 A1 Sep. 11, 2014

C. Exactly 5 g of SAP are uniformly sprinkled onto a previ where ously marked/centered area of 10x10 cm. A further non the QI value is the value of the Swell index deter woven having the same dimensions is sprayed with the adhe mined as per the herein described test method ix10 sive in the same way and then placed with the adhesive side seconds after adding the 0.9% by weight NaCl solu down onto the SAP ply to obtain an absorbent core having the tion, and following layer sequence: the PIo value is the value of the permeability index 0153 nonwoven determined as per the herein described test method ix10 seconds after adding the 0.9% by weight NaCl 0154 adhesive Solution. O155 SAP 2. The particulate absorbent polymer material according to 0156 adhesive claim 1, wherein the particulate absorbent polymer material 0157 nonwoven. has the following property: i) a maximum APC value a 1.6 for at least one num 0158. This was followed by pressing the layers together ber i from the group of integers from 2 to 12. using a hand roller. The absorbent core was Subsequently 3. The particulate absorbent polymer material according to stored for one hour to dry the adhesive before the core was claim 2, wherein the particulate absorbent polymer material measured. has the following property: 0159. To determine the absorption properties of the absor i) a maximum APC value 22.0 for at least one num bent core, the core to be tested was weighed and placed on a ber i from the group of integers from 2 to 12. wire mesh having a mesh size of 9x9 mm (wire thickness 15 4. The particulate absorbent polymer material according to mm) and an external size of 12x12 cm, which was placed in claim 3, wherein the particulate absorbent polymer material a Petri dish using four approximately 1.2 cm high metal feet has the following property: positioned at the corners of the wire mesh. The absorbent core i) a maximum APC value 22.4 for at least one num is loaded with a weight of 200 gusing a test plate (10x10 cm). ber i from the group of integers from 2 to 12. This test plate is equipped in the middle with an addition tube 5. The particulate absorbent polymer material according to 20 cm in height and 20 mm in inside diameter. This addition claim 1, wherein the particulate absorbent polymer material tube can be used to pass test fluid through the test plate onto has the following property: the absorbent core while the absorbent core is under the ii) a values 12 for the Sum total of all APC, values for pressure of the test plate. all numbers i from the group of integers from 2 to 12. 0160 Four times in succession 25 g at a time of a 0.9% 6. The particulate absorbent polymer material according to NaCl solution slightly colored with acid fuchsine are intro claim 5, wherein the particulate absorbent polymer material duced into the addition tube (delay time between the indi has the following property: vidual additions: 15 minutes). The absorbent core is weighed ii) a values 18 for the Sum total of all APC, values for before the first addition (w1). The test solution is in each case all numbers i from the group of integers from 2 to 12. added via the addition tube. On complete imbibition of liquid 7. The particulate absorbent polymer material according to (4x25 g 100 g) the absorbent core is reweighed (w2). The claim 6, wherein the particulate absorbent polymer material leakage amount (1) can be determinedarithmetically from the has the following property: difference between the added liquid quantity w0 and the difference in the weight of the absorbent core before and after ii) a value 224 for the sum total of all APC values for absorption (1=wo-(w2-w1). all numbers i from the group of integers from 2 to 12. 8. The absorbent core containing 0161 The following measurements were obtained: an upper Substrate layer, a lower Substrate layer and an absorption layer arranged between the upper and the TABLE 4 lower substrate layers, wherein the absorption layer Leakage values of polymers from the comparative example and Examples includes a particulate absorbent polymer material 1 and 2 in an absorbent core of the present invention according to claim landless than 0.1 g of cellulose fibers per gram of particulate absorbent polymer material. Polymer Leakage gafter fourfold addition 9. The absorbent core according to claim 8, wherein the Comparative example 18.7 absorbent core is essentially free of cellulose fibers. Example 1 8.4 10. The absorbent core according to claim 8, wherein the Example 2 12.9 absorbent core contains a thermoplastic material and a mul tiplicity of compartments containing the particulate absor bent polymer material. 1. A particulate absorbent polymer material having at least 11. The absorbent core according to claim 10, wherein the one of the following properties: absorbent core contains layers ofathermoplastic material and i) a maximum APCo value a 1.6 for at least one num a multiplicity of compartments containing the particulate ber i selected from the group of integers from 2 to 12 absorbent polymer material, wherein the compartments are (APC value); each bounded by the upper or lower substrate layer and also ii) a values 12 for the sum total of all APC values for by a layer of the thermoplastic material. all numbers i from the group of integers from 2 to 12 12. The absorbent core according to claim 11, wherein the absorbent core contains a first Sub-layer and a second Sub (APC): layer adjoining the first Sub-layer, wherein wherein the APC. value is defined as follows: ix1O see the first Sub-layer contains the upper Substrate layer and APC. Io e-QI. Io evalue 2 xPI, lose-value also compartments containing the particulate absorbent US 2014/0257223 A1 Sep. 11, 2014 12

polymer material which are bounded by the upper sub strate layer and a first layer of a thermoplastic material, and the second Sub-layer contains the lower Substrate layer and also compartments containing the particulate absorbent polymer material which are bounded by the lower sub strate layer and a second layer of a thermoplastic mate rial, wherein the first layer of thermoplastic material adjoins the second layer of thermoplastic material. 13. The absorbent core according to claim 8, wherein the layer of a thermoplastic material is obtainable by melting a fibrous thermoplastic material. 14. The hygiene article comprising an absorbent core according to claim 8. 15. The hygiene article according to claim 14, wherein the hygiene article is a diaper. 16. The process for producing an absorbent core containing an upper Substrate layer, a lower Substrate layer and also an absorption layer arranged between the upper and the lower Substrate layers, wherein the absorption layer comprises a particulate absorbent polymer material and less than 0.1 g of cellulose fibres per gram of particulate absorbent polymer material, containing the steps of A) providing a particulate absorbent polymer material according to claim 1: B) incorporating the particulate absorbent material in an absorbent core. 17. The absorbent core obtainable by a process according to claim 16.