EP2429597A2

EP2429597A2 - Deodorizing compositions

Info

Publication number: EP2429597A2
Application number: EP10721421A
Authority: EP
Inventors: Volker Braig; Thomas Daniel
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2009-05-14
Filing date: 2010-05-10
Publication date: 2012-03-21
Also published as: WO2010130666A2; CN102421460A; JP2012526877A; WO2010130666A3; US20120058074A1

Abstract

The invention relates to deodorizing compositions which contain water-absorbing polymer particles and at least one oxidase.

Description

Odor-inhibiting compositions

description

The present invention relates to odor-inhibiting compositions containing water-absorbing polymer particles and at least one oxidase.

Water-absorbing polymer particles are used in the manufacture of diapers, tampons, sanitary napkins and other hygiene articles, but also as water-retaining agents in agricultural horticulture. The water-absorbing polymer particles are also referred to as superabsorbers.

The preparation of water-absorbing polymer particles is described in the monograph "Modern Superabsorbent Polymer Technology", F.L. Buchholz and AT. Graham, Wiley-VCH, 1998, pages 71-103.

The properties of the water-absorbing polymer particles can be adjusted, for example, via the amount of crosslinker used. As the amount of crosslinker increases, the centrifuge retention capacity (CRC) decreases and the absorption under a pressure of 21.0 g / cm ² (AULO.3psi) goes through a maximum.

In order to improve the application properties, such as permeability of the swollen gel bed (SFC) in the diaper and absorption under a pressure of 49.2 g / cm ² (AULO.7 psi), water-absorbing polymer particles are generally surface postcrosslinked. As a result, the degree of crosslinking of the particle surface increases, whereby the absorption under a pressure of 49.2 g / cm ² (AULO.7 psi) and the centrifuge retention capacity (CRC) can be at least partially decoupled. This surface postcrosslinking can be carried out in aqueous gel phase. Preferably, however, dried, ground and sieved polymer particles (base polymer) are coated on the surface with a surface postcrosslinker, thermally surface postcrosslinked and dried. Crosslinkers suitable for this purpose are compounds which can form covalent bonds with at least two carboxylate groups of the water-absorbing polymer particles.

WO 99/08726 A1 teaches the use of combinations of haloperoxidases and hydrogen peroxide sources for odor inhibition.

WO 2004/112851 A1 describes enzyme-containing compositions which can be used, for example, as wound dressings. In particular, lactate oxidase is said to degrade lactate containing wounds and to prevent hyperacidity. WO 2006/078868 A2 discloses a food preservative system consisting of a superabsorbent material and bacterial inhibitors.

The object of the present invention was to provide an improved process for producing odor-inhibiting water-absorbing polymer particles.

The object has been achieved by odor-inhibiting compositions comprising water-absorbing polymer particles and at least one oxidase, wherein the composition is substantially free of peroxidases or the specific catalytic peroxidase activity of the composition is less than 0.001 μmol substrate g ^-1 min ^-1 .

Oxidases transfer electrons released by the oxidation of the substrate to oxygen to form hydrogen peroxide. According to the systematic nomenclature of the International Union of Biochemistry (IUB) Enzyme Commission, oxidases belong to the first class of enzymes.

Suitable oxidases are oxidases of group EC 1.1.3.x, such as glucose oxidases (EC number 1.1.3.4), group EC 1.3.3.x, such as bilirubin oxidases (EC number 1.3.3.5), group EC 1.4.3 .x, such as glycine oxidases (EC number 1.4.3.19), the group EC 1.5.3.x, such as polyamine oxidases (EC number 1.5.3.1 1), the group EC 1.6.3.x, such as NAD (P) H -Oxidases (EC number 1.6.3.1), the group EC 1.7.3.x, such as hydroxylamine oxidases (EC number 1.7.3.4), the group EC 1.8.3.x, such as sulfite oxidases (EC number 1.8. 3.1), group EC 1.9.3.x, such as cytochrome oxidases (EC number 1.9.3.1), group EC 1.10.3.x, such as catechol oxidases (EC number 1.10.3.1), group EC 1.16.3. x, such as ferroxidase (EC number 1.16.3.1), the group EC 1.17.3.x, such as xanthine oxidases (EC number 1.17.3.2), and the group EC 1.21.3.Z, such as reticulin oxidases (EC). Number 1.21.3.3).

Advantageously, a glucose oxidase (EC number 1.1.3.4) is used. It is even more advantageous if the glucose oxidase contains very little or no catalase (EC number 1.1 1.1.6).

The oxidases can also be used encapsulated, so that they are available only when adding liquid, for example by coating with water-soluble polymers such as polyvinyl alcohol.

The specific catalytic oxidase activity of the odor-inhibiting composition is preferably 0.01 to 1,000 .mu.mol substrate g- ¹ ^min-1, more preferably from 0.1 to 100 .mu.mol substrate g- ¹ min ^"1, most preferably 1 to 10 μmol substrate g- ¹ min " ¹ . The specific catalytic oxidase activity of the composition can be determined by conventional methods. However, it is better to determine the catalytic activity of the oxidase itself and to calculate the specific catalytic oxidase activity of the composition by calculation.

The odor-inhibiting compositions may additionally contain the substrate of the oxidase. A Substart is a compound that is converted by the enzyme in a chemical reaction. The first step in an enzymatic reaction is the formation of an enzyme-substrate complex, which after the reaction leads to the release of product and enzyme, so that the catalytic cycle can be run through again. An enzyme can possibly convert several different substrates, which are often chemically similar. Substrates for the purposes of the present invention are substrates of the oxidases which can be used according to the invention, for example β-D-glucose for glucose oxidase.

It is preferably from 0.5 to 25 wt .-%, particularly preferably from 5 to 20 wt .-%, most preferably from 8 to 15 wt .-% of the substrate used, each based on the water-absorbing polymer particles.

The substrates can also be used in encapsulated form, so that they are only available when oxidase is added to the liquid, for example by coating with water-soluble polymers such as polyvinyl alcohol. However, it is also possible instead or in addition to encapsulate the oxidases to be used according to the invention.

The present invention is based on the finding that oxidases can reduce unpleasant odors in hygiene articles, especially unpleasant odors caused by sulfur compounds. This may be due to hydrogen peroxide generated as a result of the catalytic oxidase activity. Peroxidases decompose hydrogen peroxide. Therefore, the simultaneous use of peroxidases should be avoided.

The composition according to the invention preferably contains at least 90% by weight, particularly preferably at least 95% by weight, very particularly preferably at least 97% by weight, of water-absorbing polymer particles.

The water-absorbing polymer particles preferably contain at least 50% by weight of polymerized acrylic acid or its salts. Furthermore, the water-absorbing polymer particles are preferably surface-postcrosslinked.

In a preferred embodiment of the present invention, the water-absorbing polymer particles are coated with a zinc salt. Suitable zinc salts are, for example, zinc hydroxide, zinc sulfate, zinc chloride, zinc citrate, zinc acetate and zinc lactate. Preferably, zinc salts of fatty acids such as ricinoleic acid are used.

The amount of zinc salt used is preferably 0.01 to 5 wt .-%, particularly preferably 0.05 to 3 wt .-%, most preferably 0.1 to 1 wt .-%, each based on the water-absorbing polymer.

The zinc salts are usually used as a solution in a suitable solvent, preferably water.

By additional coating of the polymer particles with zinc salts, the tendency to discoloration of the water-absorbing polymer particles can be favorably influenced.

The preparation of the water-absorbing polymer particles is explained in more detail below.

The water-absorbing polymer particles are obtained, for example, by polymerization of a monomer solution or suspension containing

a) at least one ethylenically unsaturated, acid group-carrying monomer which may be at least partially neutralized, b) at least one crosslinker, c) at least one initiator, d) optionally one or more ethylenically unsaturated monomers copolymerizable with the monomers mentioned under a) and e ) optionally one or more water soluble polymers, and are usually water insoluble.

The monomers a) are preferably water-soluble, i. the solubility in water at 23 ° C. is typically at least 1 g / 100 g of water, preferably at least 5 g / 100 g of water, more preferably at least 25 g / 100 g of water, most preferably at least 35 g / 100 g of water.

Suitable monomers a) are, for example, ethylenically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, and itaconic acid. Particularly preferred monomers are acrylic acid and methacrylic acid. Very particular preference is given to acrylic acid.

Further suitable monomers a) are, for example, ethylenically unsaturated sulfonic acids, such as styrenesulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid (AMPS).

Impurities can have a significant influence on the polymerization. Therefore, the raw materials used should have the highest possible purity. It is therefore often advantageous to clean the monomers a) specifically. Suitable purification processes are described, for example, in WO 2002/055469 A1, WO 2003/078378 A1 and WO 2004/035514 A1. A suitable monomer a) is, for example, an acrylic acid purified according to WO 2004/035514 A1 with 99.8460% by weight of acrylic acid, 0.0950% by weight of acetic acid, 0.0332% by weight of water, 0.0203% by weight. % Propionic acid, 0.0001% by weight of furfurals, 0.0001% by weight of maleic anhydride, 0.0003% by weight of diacrylic acid and 0.0050% by weight of hydroquinone monomethyl ether.

The proportion of acrylic acid and / or salts thereof in the total amount of monomers a) is preferably at least 50 mol%, particularly preferably at least 90 mol%, very particularly preferably at least 95 mol%.

The monomers a) usually contain polymerization inhibitors, preferably hydroquinone half ethers, as a storage stabilizer.

The monomer solution preferably contains up to 250 ppm by weight, preferably at most 130 ppm by weight, more preferably at most 70 ppm by weight, preferably at least 10 ppm by weight, particularly preferably at least 30 ppm by weight, in particular by 50% by weight . ppm, hydroquinone, in each case based on the unneutralized monomer a). For example, an ethylenically unsaturated, acid group-carrying monomer having a corresponding content of hydroquinone half-ether can be used to prepare the monomer solution.

Preferred hydroquinone half ethers are hydroquinone monomethyl ether (MEHQ) and / or alpha-tocopherol (vitamin E).

Suitable crosslinkers b) are compounds having at least two groups suitable for crosslinking. Such groups are, for example, ethylenically unsaturated groups which can be radically copolymerized into the polymer chain, and functional groups which can form covalent bonds with the acid groups of the monomer a). Furthermore, polyvalent metal salts which can form coordinative bonds with at least two acid groups of the monomer a) are also suitable as crosslinking agents b).

Crosslinkers b) are preferably compounds having at least two polymerizable groups which can be incorporated in the polymer network in free-radically polymerized form. Suitable crosslinkers b) are, for example, ethylene glycol dimethacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, allyl methacrylate, trimethylolpropane triacrylate, triallylamine, tetraallylammonium chloride, tetraallyloxyethane, as described in EP 0 530 438 A1, di- and triacrylates, as in EP 0 547 847 A1, EP 0 559 476 A1,

EP 0 632 068 A1, WO 93/21237 A1, WO 2003/104299 A1, WO 2003/104300 A1, WO 2003/104301 A1 and DE 103 31 450 A1, mixed acrylates which acrylate groups further ethylenically unsaturated groups, as described in DE 103 31 456 A1 and DE 103 55 401 A1, or crosslinker mixtures, such as in DE 195 43 368 A1, DE 196 46 484 A1, WO 90/15830 A1 and WO 2002 / 032962 A2.

Preferred crosslinkers b) are pentaerythritol triallyl ether, tetraalloxyethane, methylenebis-methacrylamide, 15-times ethoxylated trimethylolpropane triacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate and triallylamine.

Very particularly preferred crosslinkers b) are the polyethoxylated and / or propoxylated glycerols esterified with acrylic acid or methacrylic acid to form di- or triacrylates, as described, for example, in WO 2003/104301 A1. Particularly advantageous are di- and / or triacrylates of 3- to 10-fold ethoxylated glycerol. Very particular preference is given to diacrylates or triacrylates of 1 to 5 times ethoxylated and / or propoxylated glycerol. Most preferred are the triacrylates of

3- to 5-fold ethoxylated and / or propoxylated glycerol, in particular the triacylate of 3-times ethoxylated glycerol.

The amount of crosslinker b) is preferably 0.05 to 1.5% by weight, more preferably 0.1 to 1% by weight, most preferably 0.3 to 0.6% by weight, in each case based on monomer a). As the crosslinker content increases, the centrifuge retention capacity (CRC) decreases and the absorption under a pressure of 21.0 g / cm ² passes through a maximum.

As initiators c) it is possible to use all compounds which generate free radicals under the polymerization conditions, for example thermal initiators, redox initiators, photoinitiators. Suitable redox initiators are sodium peroxodisulfate / ascorbic acid, hydrogen peroxide / ascorbic acid, sodium peroxodisulfate / sodium bisulfite and hydrogen peroxide / sodium bisulfite. Preference is given to using mixtures of thermal initiators and redox initiators, such as sodium peroxodisulfate / hydrogen peroxide / ascorbic acid. However, the reducing component used is preferably a mixture of the sodium salt of 2-hydroxy-2-sulfinatoacetic acid, the disodium salt of 2-hydroxy-2-sulfonatoacetic acid and sodium bisulfite. Such mixtures are available as Brüggolite® FF6 and Brüggolite® FF7 (Brüggemann Chemicals; Heilbronn; DE).

For example, acrylamide, methacrylamide, hydroxyethyl acrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, diethylaminopropyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate are examples of the ethylenically unsaturated, acid group-carrying monomers a) copolymerizable ethylenically unsaturated monomers d). As water-soluble polymers e) it is possible to use polyvinyl alcohol, polyvinylpyrrolidone, starch, starch derivatives, modified cellulose, such as methylcellulose or hydroxyethylcellulose, gelatin, polyglycols or polyacrylic acids, preferably starch, starch derivatives and modified cellulose.

Usually, an aqueous monomer solution is used. The water content of the monomer solution is preferably from 40 to 75 wt .-%, particularly preferably from 45 to 70 wt .-%, most preferably from 50 to 65 wt .-%. It is also possible monomer suspensions, i. Monomer solutions with excess monomer a), for example sodium acrylate, use. With increasing water content, the energy expenditure increases during the subsequent drying and with decreasing water content, the heat of polymerization can only be dissipated insufficiently.

The preferred polymerization inhibitors require dissolved oxygen for optimum performance. Therefore, the monomer solution may be polymerized prior to polymerization by inerting, i. Flow through with an inert gas, preferably nitrogen or carbon dioxide, are freed of dissolved oxygen. Preferably, the oxygen content of the monomer solution before polymerization is reduced to less than 1 ppm by weight, more preferably less than 0.5 ppm by weight, most preferably less than 0.1 ppm by weight.

Suitable reactors are, for example, kneading reactors or belt reactors. In the kneader, the polymer gel formed during the polymerization of an aqueous monomer solution or suspension is comminuted continuously by, for example, counter-rotating stirring shafts, as described in WO 2001/038402 A1. The polymerization on the belt is described, for example, in DE 38 25 366 A1 and US Pat. No. 6,241,928. During the polymerization in a belt reactor, a polymer gel is formed, which must be comminuted in a further process step, for example in an extruder or kneader.

However, it is also possible to drip an aqueous monomer solution and to polymerize the drops produced in a heated carrier gas stream. Here, the process steps polymerization and drying can be summarized, as described in WO 2008/040715 A2 and WO 2008/052971 A1.

The acid groups of the polymer gels obtained are usually partially neutralized. The neutralization is preferably carried out at the stage of the monomers. This is usually done by mixing the neutralizing agent as an aqueous solution or preferably as a solid. The degree of neutralization is preferably from 25 to 85 mol%, for "acidic" polymer gels, particularly preferably from 30 to 60 mol%, very particularly preferably from 35 to 55 mol%, for "neutral" polymer gels, particularly preferably from 65 to 80 mol %, very particularly preferably from 70 to 75 mol%, it being possible to use the customary neutralizing agents, preferably alkali metal hydroxides, alkali metal oxides, alkali metal carbonates or alkali metal bicarbonates and mixtures thereof. Instead of alkali metal salts and ammonium salts can be used. Sodium and potassium are particularly preferred as alkali metals, but very particularly preferred are sodium hydroxide, sodium bicarbonate or sodium bicarbonate and mixtures thereof.

However, it is also possible to carry out the neutralization after the polymerization at the stage of the polymer gel formed during the polymerization. Furthermore, it is possible to neutralize up to 40 mol%, preferably 10 to 30 mol%, particularly preferably 15 to 25 mol%, of the acid groups before the polymerization by adding a part of the neutralizing agent already to the monomer solution and the desired final degree of neutralization only after the polymerization is adjusted at the stage of the polymer gel. If the polymer gel is neutralized at least partially after the polymerization, the polymer gel is preferably comminuted mechanically, for example by means of an extruder, wherein the neutralizing agent can be sprayed, sprinkled or poured on and then thoroughly mixed in. For this purpose, the gel mass obtained can be extruded several times for homogenization.

The polymer gel is then preferably dried with a belt dryer until the residual moisture content is preferably 0.5 to 15 wt .-%, particularly preferably 1 to

10 wt .-%, most preferably 2 to 8 wt .-%, wherein the residual moisture content according to the recommended by the EDANA (European Disposables and Nonwovens Association) Test Method No. WSP 230.2-05 "Moisture Content" is determined. If the residual moisture content is too high, the dried polymer gel has too low a glass transition temperature T ₉ and is difficult to process further. If the residual moisture content is too low, the dried polymer gel is too brittle and in the subsequent comminution steps undesirably large quantities of polymer particles with too small particle size ("fines") are produced. , more preferably from 35 to 70% by weight, most preferably from 40 to 60% by weight. Alternatively, a fluidized bed dryer or a paddle dryer can be used for drying.

The dried polymer gel is then ground and classified, wherein for grinding usually one- or multi-stage roller mills, preferably two- or three-stage roller mills, pin mills, hammer mills or vibratory mills, can be used.

The mean particle size of the polymer fraction separated as a product fraction is preferably at least 200 μm, more preferably from 250 to 600 μm, very particularly from 300 to 500 μm. The mean particle size of the product fraction can be determined by means of the methods recommended by the EDANA (European Disposables and Nonwovens Association). foamed test method no. WSP 220.2-05 "particle size distribution", whereby the mass fractions of the sieve fractions are cumulatively applied and the average particle size is determined graphically. The mean particle size here is the value of the mesh size, which results for accumulated 50 wt .-%.

The proportion of particles having a particle size of at least 150 .mu.m is preferably at least 90 wt .-%, more preferably at least 95 wt .-%, most preferably at least 98 wt .-%.

Polymer particles with too small particle size lower the permeability (SFC). Therefore, the proportion of too small polymer particles ("fines") should be low.

Too small polymer particles are therefore usually separated and recycled to the process. This preferably occurs before, during or immediately after polymerization, i. before drying the polymer gel. The too small polymer particles can be moistened with water and / or aqueous surfactant before or during the recycling.

It is also possible to separate small polymer particles in later process steps, for example after surface postcrosslinking or another coating step. In this case, the recycled too small polymer particles are surface postcrosslinked or otherwise coated, for example with fumed silica.

If a kneading reactor is used for the polymerization, the too small polymer particles are preferably added during the last third of the polymerization. If the polymer particles which are too small are added very early, for example already to the monomer solution, this lowers the centrifuge retention capacity (CRC) of the resulting water-absorbing polymer particles. However, this can be compensated for example by adjusting the amount of crosslinker b).

If the polymer particles which are too small are added very late, for example only in an apparatus downstream of the polymerization reactor, for example an extruder, then the polymer particles which are too small are difficult to incorporate into the polymer gel obtained. Insufficiently incorporated too small polymer particles, however, dissolve again during the grinding of the dried polymer gel, are therefore separated again during classification and increase the amount of recycled too small polymer particles. The proportion of particles having a particle size of at most 850 microns, is preferably at least 90 wt .-%, more preferably at least 95 wt .-%, most preferably at least 98 wt .-%. The proportion of particles having a particle size of at most 600 μm is preferably at least 90% by weight, particularly preferably at least 95% by weight, very particularly preferably at least 98% by weight.

Polymer particles with too large particle size reduce the swelling rate. Therefore, the proportion of polymer particles too large should also be low.

Too large polymer particles are therefore usually separated and recycled to the grinding of the dried polymer gel.

The polymer particles can be postcrosslinked to further improve the properties. Suitable surface postcrosslinkers are compounds containing groups that can form covalent bonds with at least two carboxylate groups of the polymer particles. Suitable compounds are, for example, polyfunctional amines, polyfunctional amidoamines, polyfunctional epoxides, as described in EP 0 083 022 A2, EP 0 543 303 A1 and EP 0 937 736 A2, di- or polyfunctional alcohols, as described in DE 33 14 019 A1, DE 35 23 617 A1 and EP 0 450 922 A2, or β-hydroxyalkylamides, as described in DE 102 04 938 A1 and US Pat. No. 6,239,230.

Furthermore, in DE 40 20 780 C1 cyclic carbonates, in DE 198 07 502 A1 2-oxazolidone and its derivatives, such as 2-hydroxyethyl-2-oxazolidone, in DE 198 07 992 Ci bis- and poly-2-oxazolidinone, in DE 198 54 573 A1 2-Oxotetrahydro-1,3-oxazine and its derivatives, in DE 198 54 574 A1 N-acyl-2-oxazolidones, in DE 102 04 937 A1 cyclic ureas, in DE 103 34 584 A1 bicyclic amide acetals, in

EP 1 199 327 A2 oxetanes and cyclic ureas and described in WO 2003/031482 A1 morpholine-2,3-dione and its derivatives as suitable surface postcrosslinkers.

Preferred surface postcrosslinkers are ethylene carbonate, ethylene glycol diglycidyl ether, reaction products of polyamides with epichlorohydrin and mixtures of propylene glycol and 1,4-butanediol.

Very particularly preferred surface postcrosslinkers are 2-hydroxyethyloxazolidin-2-one, oxazolidin-2-one and 1,3-propanediol.

Furthermore, it is also possible to use surface postcrosslinkers which contain additional polymerizable ethylenically unsaturated groups, as described in DE 37 13 601 A1 The amount of surface postcrosslinker is preferably 0.001 to 2 wt .-%, more preferably 0.02 to 1 wt .-%, most preferably 0.05 to 0.2 wt .-%, each based on the polymer particles.

In a preferred embodiment of the present invention, polyvalent cations are applied to the particle surface before, during or after the surface postcrosslinking in addition to the surface postcrosslinkers.

The polyvalent cations which can be used in the process according to the invention are, for example, divalent cations, such as the cations of zinc, magnesium, calcium, iron and strontium, trivalent cations, such as the cations of aluminum, iron, chromium, rare earths and manganese, tetravalent cations, such as Cations of titanium and zirconium. As a counterion, for example, chloride, bromide, sulfate, hydrogen sulfate, carbonate, bicarbonate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate and carboxylate, such as acetate and lactate, are possible. Aluminum sulfate and aluminum lactate are preferred. In addition to metal salts, polyamines can also be used as polyvalent cations.

The amount of polyvalent cation used is, for example, 0.001 to 1.5% by weight, preferably 0.005 to 1% by weight, particularly preferably 0.02 to 0.8% by weight. in each case based on the polymer particles.

The surface postcrosslinking is usually carried out so that a solution of the surface postcrosslinker is sprayed onto the dried polymer particles. Subsequent to the spraying, the surface postcrosslinker coated polymer particles are thermally dried, whereby the surface postcrosslinking reaction can take place both before and during drying.

The spraying of a solution of the surface postcrosslinker is preferably carried out in mixers with agitated mixing tools, such as screw mixers, disc mixers and paddle mixers. Particularly preferred are horizontal mixers, such as paddle mixers, very particularly preferred are vertical mixers. The distinction in horizontal mixer and vertical mixer via the storage of the mixing shaft, ie horizontal mixer have a horizontally mounted mixing shaft and vertical mixer have a vertically mounted mixing shaft. Suitable mixers are, for example, Horizontal Pflugschar® mixers (Gebr. Lödige Maschinenbau GmbH, Paderborn, DE), Vrieco-Nauta Continuous Mixers (Hosokawa Micron BV, Doetinchem, NL), Processall Mixmill Mixers (Processall Incorporated, Cincinnati, US) and Schugi Flexomix® (Hosokawa Micron BV, Doetinchem, NL). However, it is also possible to spray the surface postcrosslinker solution in a fluidized bed. The surface postcrosslinkers are typically used as an aqueous solution. The penetration depth of the surface postcrosslinker into the polymer particles can be adjusted by the content of nonaqueous solvent or total solvent amount.

If only water is used as the solvent, it is advantageous to add a surfactant. This improves the wetting behavior and reduces the tendency to clump. However, preference is given to using solvent mixtures, for example isopropanol / water, 1,3-propanediol / water and propylene glycol / water, the mixing mass ratio preferably being from 20:80 to 40:60.

The thermal drying is preferably carried out in contact dryers, more preferably paddle dryers, very particularly preferably disk dryers. Suitable dryers include Hosokawa Bepex® Horizontal Paddle Dryer (Hosokawa Micron GmbH, Leingarten, DE), Hosokawa Bepex® Disc Dryer (Hosokawa Micron GmbH, Leingarten, DE), and Nara Paddle Dryer (NARA Machinery Europe, Frechen, DE). Moreover, fluidized bed dryers can also be used.

The drying can take place in the mixer itself, by heating the jacket or blowing hot air. Also suitable is a downstream dryer, such as a hopper dryer, a rotary kiln or a heatable screw. Particularly advantageous is mixed and dried in a fluidized bed dryer.

Preferred drying temperatures are in the range 100 to 250 ⁰ C, preferably

120 to 220 ^° C., particularly preferably 130 to 210 ^° C., very particularly preferably 150 to 200 ^° C. The preferred residence time at this temperature in the reaction mixer or dryer is preferably at least 10 minutes, particularly preferably at least 20 minutes, very particularly preferably at least 30 Minutes, and usually at most 60 minutes.

Subsequently, the surface-postcrosslinked polymer particles can be classified again, wherein too small and / or too large polymer particles are separated and recycled to the process.

The surface-postcrosslinked polymer particles can be coated or post-moistened for further improvement of the properties.

The subsequent moistening is carried out preferably at 30 to 8O ⁰ C, particularly preferably at 35 to 70 ⁰ C, most preferably at 40 to 6O ⁰ C. If the temperatures are too low, the water-absorbing polymer particles tend to clump together and at higher temperatures water is already noticeably evaporating. The post-moisturizing The amount of water used is preferably from 1 to 10 wt .-%, particularly preferably from 2 to 8 wt .-%, most preferably from 3 to 5 wt .-%. By rewetting the mechanical stability of the polymer particles is increased and their tendency to static charge reduced.

Suitable coatings for improving the swelling rate and the permeability (SFC) are, for example, inorganic inert substances, such as water-insoluble metal salts, organic polymers, cationic polymers and di- or polyvalent metal cations. Suitable coatings for dust binding are, for example, polyols. Suitable coatings against the undesirable tendency for the polymer particles to cake are, for example, fumed silica, such as Aerosil® 200, and surfactants, such as Span® 20.

The water-absorbing polymer particles have a moisture content of preferably from 1 to 15% by weight, particularly preferably from 2 to 10% by weight, very particularly preferably from 3 to 5% by weight, the moisture content being determined according to the method described by EDANA (cf. European Disposables and Nonwovens Association) recommended test method No. WSP 230.2-05 "Moisture Content".

The water-absorbing polymer particles have a centrifuge retention capacity (CRC) of typically at least 15 g / g, preferably at least 20 g / g, preferably at least 22 g / g, more preferably at least 24 g / g, most preferably at least 26 g / g. The centrifuge retention capacity (CRC) of the water-absorbing polymer particles is usually less than 60 g / g. The centrifuge retention capacity (CRC) is determined according to the test method No. WSP 241.2-05 "Centrifuge Retention Capacity" recommended by EDANA (European Disposables and Nonwovens Association).

The water-absorbing polymer particles have an absorption under a pressure of 49.2 g / cm ² of typically at least 15 g / g, preferably at least

20 g / g, preferably at least 22 g / g, more preferably at least 24 g / g, most preferably at least 26 g / g. The absorption under a pressure of 49.2 g / cm ^{2 of} the water-absorbent polymer particles is usually less than 35 g / g. The absorption under a pressure of 49.2 g / cm ² is determined analogously to the recommended by the EDANA (European Disposables and Nonwovens Association) Test Method No. WSP 242.2-05 "absorption under pressure", instead of a pressure of 21, 0 g / cm ² a pressure of 49.2 g / cm ^{2 is} set.

Another object of the present invention are methods for preparing the compositions of the invention, wherein i) at least one oxidase is mixed together with water-absorbing polymer particles and / or ii) at least one oxidase is milled together with water-absorbing polymer particles and / or iii) at least one oxidase is sprayed onto water-absorbing polymer particles and iv) optionally according to i), ii) and / or iii) the composition obtained is mixed together with water-absorbing polymer particles.

Variants i) and iii) are preferred.

In a preferred embodiment of the present invention, the water-absorbing polymer particles are additionally mixed with the substrate of the oxidase, variants i) to iv) being likewise suitable.

The nature of the mixing is not limited and may already take place in the preparation of the water-absorbing polymer particles, for example, after cooling after surface postcrosslinking or subsequent classification, or in a special mixer. Suitable mixers have already been described above in the surface postcrosslinking of the water-absorbing polymer particles.

The type of grinding is also subject to no restriction. Suitable apparatuses have already been described above in the comminution of the water-absorbing polymer particles.

The type of spraying is subject to no restriction.

In a further preferred embodiment of the present invention, a composition A) according to the invention containing water-absorbing polymer particles and at least one oxidase and a further composition B) comprising water-absorbing polymer particles and at least one substrate of the at least one oxidase is prepared separately and then mixed.

The mixing ratio of composition A) to composition B) is preferably from 0.01 to 100, more preferably from 0.1 to 10, most preferably from 0.5 to 2.

The type of mixing is not limited.

In the preparation of powder mixtures of water-absorbing polymer particles, at least one oxidase and optionally at least one substrate dedusting agents are advantageously used. Suitable dedusting agents are polyglycerides ne, polyethylene glycols, polypropylene glycols, random or block copolymers of ethylene oxide and propylene oxide. Other dedusting agents which are suitable for this purpose are the polyethoxylates or polypropoxylates of polyhydroxy compounds, such as glycerol, sorbitol, trimethylolpropane, trimethylolethane and pentaerythritol. Examples of these are n-times ethoxylated trimethylolpropane or glycerol, where n is an integer between 1 and 100. Further examples are block copolymers, such as a total of n-times ethoxylated and then m-fold propoxylated trimethylolpropane or glycerol, where n is an integer between 1 and 40 and m is an integer between 1 and 40. The order of the blocks can also be reversed.

The oxidase can be used as crude extract or concentrated. It is also possible to use immobilized oxidases on a support. Suitable carriers are, for example, clay minerals, bentonites, silica gels, flour, cellulose, water-insoluble phosphates, carbonates or sulfates, as well as cationic, nonionic or anionic polymers, activated carbon, aluminum oxides, titanium dioxide, pyrogenic silica. The carriers can be both granular and fibrous. The attachment to the support may be covalent or absorptive.

In a further embodiment, a composition according to the invention is prepared which has a higher specific catalytic peroxidase activity, usually 1 to 1,000 .mu.mol of substrate g- ¹ min- ¹ , preferably 5 to 5,000 .mu.mol substrate g- ¹ min- ¹ , particularly preferably 10 to 1,000 .mu.mol Substrate g- ¹ min- ¹ . The highly concentrated composition thus obtained can then be diluted with other water-absorbing polymer particles to the desired final content.

In a further preferred embodiment, a mixture of at least two compositions based on water-absorbing polymer particles is prepared, one of which contains the enzyme and the other the substrate. The mixing ratio can vary from 1 to 99 up to 99 to 1. Particularly preferred is a mixture of similarly sized water-absorbing polymer particles.

The type of mixing is not limited and may already be carried out during the preparation of one of the two compositions, for example, after surface postcrosslink cooling, subsequent classification, or in a special mixer. Suitable mixers have already been described above in the surface postcrosslinking of the water-absorbing polymer particles.

Further articles of the present invention are hygiene articles containing at least one composition according to the invention, and hygiene articles containing water-absorbing polymer particles, at least one oxidase and a substrate of the oxidase, wherein the oxidase is substantially free of peroxidases or less than the specific catalytic peroxidase activity of the oxidase 0.001 μmol of sub- gat- ¹ min- ¹ , in particular hygiene articles for feminine hygiene, hygiene articles for light and severe incontinence or small animal litter.

The sanitary articles usually contain a water-impermeable back, a water-permeable upper side and in between an absorbent core of the water-absorbing polymer particles according to the invention and cellulose fibers. The proportion of the water-absorbing polymer particles according to the invention in the absorbent core is preferably from 20 to 100% by weight, preferably from 50 to 100% by weight.

The hygiene articles according to the invention may also contain the substrate of the corresponding oxides outside the composition according to the invention. In this case, the substrate is transported to the oxidase only when the liquid is loaded.

Furthermore, the water-absorbing polymer particles, the oxidase and the substrate may also be introduced separately into the absorbent core.

The water-absorbing polymer particles are tested by the test methods described below.

methods:

The measurements should be taken at an ambient temperature of 23 ± 2 ⁰ C and a relative humidity of 50 ± 10% unless otherwise specified. The water-absorbing polymer particles are thoroughly mixed before the measurement.

Centrifuge Retention Capacity

The Centrifuge Retention Capacity (CRC) is determined according to the EDANA recommended Test Method No. WSP 241.2-05 "Centrifuge Retention Capacity".

Bacteria-induced release of ammonia

DSM1 Medium (German Collection of Microorganisms and Cell Cultures GmbH) was prepared from 5.0 g / l peptone from meat (Merck KGaA, Darmstadt, DE, Item No. 1.07214) and 3.0 g / l meat extract (Merck KGaA, Darmstadt ;

DE; Art. No. 1 103979) and adjusted to pH = 7.0. 50 ml of DSM1 medium was inoculated with Proteus mirabilis ATCC 14153 to OD = 0.1 and incubated in a 250 ml Erlenmeyer flask with chicane for 15 hours at 37 ° C and 220 rpm. The cultures thus prepared had a cell density of approximately 10 ⁹ CFU / ml (OD = 2.0-2.5).

The synthetic urine was prepared from 25 g / L urea (sterile filtered), 9.0 g / L sodium chloride, 0.5 g / L β-D-glucose, 1 g / L peptone from meat and 1 g / L meat extract. Of the Synthetic urine was autoclaved prior to adding a sterile-filtered concentrated urea solution.

125 ml polypropylene histology beakers were autoclaved and the amount of water-absorbing polymer particles necessary for the absorption of 50 ml of synthetic urine (calculated from the centrifuge retention capacity). Then, 50 ml of synthetic urine were inoculated with 50 μl of bacterial stock solution corresponding to a total concentration of about 10 ⁶ CFU / ml, mixed with the water-absorbing polymer particles and immediately filled with a diffusion test tube (Drägerwerk AG & Co. KGaA; Lübeck; DE; Dräger-Röhrchen® Ammonia 20 / aD, Item No. 8101301) screwed lid provided. Ammonia evolution was monitored at 37 ° C for 48 hours.

Examples

The examples were carried out with Hysorb® B7065 (BASF SE, Ludwigshafen, DE), commercially available sodium acrylate-based surface-postcrosslinked water-absorbing polymer particles having a degree of neutralization of from 70 to 75 mol%.

Such surface-postcrosslinked water-absorbing polymer particles are e.g. by BASF Aktiengesellschaft (trade name HySorb®), Stockhausen GmbH (trade name Favor®) and Nippon Shokubai Co., Ltd. (Trade name Aqualic®) commercially available.

example 1

20 g of water-absorbing polymer particles were weighed into a 50 ml glass bottle with 0.02 g "Gluzyme® Mono 10000 BG" (Novozymes A / S; Bagsvaerd; DK). "Gluzyme® Mono 10000 BG" is a glucose oxidase with a specific catalytic activity of 10,000 .mu.mol substrate g- ¹ min-. ¹ The mixture was then transferred to the large porcelain mortar (16 cm inner diameter) and ground there for about 5 minutes. In addition, the samples were again homogenized for 20 minutes at 46 rpm in a tumble mixer.

Example 2

Weighed 0.33g of "Multifect® GO 5000L" (Genencor International BV; Leiden, NL) into a 25ml penicillin glass and made up to 10g with ultrapure water. "Multifect® GO 5000L" is a glucose oxidase with a specific catalytic activity of 4000 μmol of substrate g- ¹ min- ¹ .

20.0 g of water-absorbing polymer particles were placed in a modified coffee grinder (Blender 8012 Model 34BL99, Waring Laboratory, US) with a stainless steel attachment (Inner diameter 8cm, inner height 4cm, tool diameter 7cm, addition point in the lid 1, 3cm from the edge, baffles in the lid) filled. The modified coffee grinder was operated at level 3. Via syringe with cannula, 0.60 g of the enzyme solution was added slowly. After the end of the addition, the water-absorbing polymer particles were transferred to a glass dish and allowed to stand for 30 minutes in a fume cupboard at room temperature.

Example 3

The procedure was as in Example 2, with 0.33 g of "GC 199 Enzyme Preparation" (Genencor International BV, Leiden, NL) being weighed into a 25 ml penicillin glass and made up to 10 g with ultrapure water. "GC 199 Enzyme Preparation" is a glucose oxidase with a specific catalytic activity of 1,500 .mu.mol substrate g- ¹ min " ¹ .

Example 4

The procedure was as in Example 1, wherein the water-absorbing polymer particles previously mixed with 12.8 wt .-% ß-D-glucose and in the production of synthetic urine, the ß-D-glucose was omitted.

Example 5

3.4 g of potassium hydrogen phosphate were weighed and made up to 250 ml with deionized water. In a second volumetric flask, 5.7 g of dipotassium hydrogen phosphate were weighed out and also made up to 250 ml. Subsequently, so much potassium hydrogen phosphate solution was added to the dipotassium hydrogen phosphate solution until a pH of 7 was reached (buffer solution).

267 mg "Gluzyme® Mono 10000 BG" (Novozymes A / S, Bagsvaerd, DK) were slurried in 80 g buffer solution (enzyme solution).

270g of water-absorbing polymer particles were filled in a Bosch MultiMixx47 type CNUM5EV (Robert Bosch Hausgeräte GmbH, Munich, DE) with a 3-directional whisk and stirred on level 3. 8.1 g of the enzyme solution were sprayed on with a spray atomizer (800 l / h of nitrogen). The mixture was then stirred for a further 10 minutes at level 1 and, after the wall covering was removed with a brush, stirred for a further 10 minutes at level 1.

50 g of this mixture were triturated in a porcelain grater dish (16 cm inner diameter) with 1 g of β-D-glucose and then homogenized for 30 minutes at 32 rpm in a tumble mixer. In the production of the synthetic urine for bacterial-induced ammonia release, the β-D-glucose was omitted. Tab. 1: Test results

Claims

claims

An odor-inhibiting composition comprising water-absorbing polymer particles and at least one oxidase, wherein the composition is substantially free of peroxidases or the specific catalytic peroxidase activity of the composition is less than 0.001 μmol of substrate g- ¹ min- ¹ .

2. Composition according to claim 1, characterized in that the composition contains the substrate of the oxidase

3. Composition according to claim 1 or 2, characterized in that the oxidase is a glucose oxidase.

4. The composition according to any one of claims 1 to 3, characterized in that the oxidase is a glucose oxidase and the composition contains glucose.

5. The composition according to any one of claims 1 to 4, characterized in that the specific catalytic oxidase activity of the composition of 0.01 to 1000 .mu.mol substrate g is ¹ min- ¹ .

6. A composition according to any one of claims 1 to 5, characterized in that the composition contains at least 90 wt .-% water-absorbing polymer particles.

7. A composition according to any one of claims 1 to 6, characterized in that the water-absorbing polymer particles contain at least 50 wt .-% polymerized acrylic acid.

8. Composition according to one of claims 1 to 7, characterized in that the water-absorbing polymer particles are surface-postcrosslinked.

9. The composition according to any one of claims 1 to 8, characterized in that the water-absorbing polymer particles have a Zentrifugeretentions- capacity of at least 15 g / g.

10. A process for the preparation of defined in one of claims 1 to 9 compositions, characterized in that one carries out at least one of the following steps, wherein i) at least one oxidase is mixed together with water-absorbing polymer particles and optionally the substrate of the oxidase and / or ii) at least one oxidase and optionally the substrate of the oxidase are milled together with water-absorbing polymers and / or iii) at least one oxidase and optionally the substrate of Oxidase is sprayed onto water-absorbing polymer particles and iv) optionally the composition obtained according to i), ii) and / or iii) are mixed together with further water-absorbing polymer particles.

1 1. Hygiene article containing at least one composition according to any one of claims 1 to 9.

12. sanitary articles containing water-absorbing polymer particles, at least one oxidase and a substrate of the oxidase, wherein the oxidase is substantially free of peroxidases or the specific catalytic peroxidase activity of the oxidase is less than 0.001 μmol substrate g- ¹ min- ¹ .

13. Hygiene article according to claim 12, characterized in that the oxidase is a glucose oxidase and the substrate is glucose.

14. Hygiene article according to claim 12 or 13, characterized in that the water-absorbing polymer particles have a centrifuge retention capacity of at least 15 g / g.

15. A hygiene article according to any one of claims 1 1 to 14, characterized in that the hygiene article is a feminine hygiene article, an article for light and heavy incontinence or small animal litter.