WO2001041819A1

WO2001041819A1 - Absorbent preparation

Info

Publication number: WO2001041819A1
Application number: PCT/EP2000/011578
Authority: WO
Inventors: Friedrich Engelhardt; Volker Frenz; Norbert Herfert
Original assignee: Basf Aktiengesellschaft
Priority date: 1999-12-06
Filing date: 2000-11-21
Publication date: 2001-06-14
Also published as: DE19958697A1

Abstract

The invention relates to an absorbent preparation containing (a) a poorly water-soluble or water-insoluble silver salt or colloidal silver and (b) a hydrogel forming polymer, the proportion of silver ranging from 0.1 to 1000 ppm of the hydrogel forming polymer.

Description

Absorbent preparation

description

The present invention relates to an absorbent preparation containing

(a) a silver salt or colloidal silver which is sparingly or insoluble in water and

(b) a hydrogel-forming polymer,

the proportion of silver being 0.1 to 1000 ppm of the hydrogel-forming polymer and the use of this mixture in hygiene articles for adults and babies and hygiene articles containing them. It also relates to the use of sparingly or insoluble silver salts or colloidal silver in hygiene articles.

Diaper rash is a common manifestation of skin irritation or inflammation in areas of the body that are usually covered by wearing a diaper. In particular, diaper dermatitis is a serious problem in adult incontinence. It is generally accepted that diaper dermatitis is a contact dermatitis that arises from long-term contact of the skin with urine and / or faeces. To date, the exact components in urine and faeces that are responsible for the occurrence of diaper rash are not yet fully known. However, it can be assumed that ammonia, bacteria, fungi, moisture and the skin pH play a decisive role in the development of diaper dermatitis. In addition to skin irritation or inflammation, the long-term contact of the skin with urine and feces also leads to the formation of nasty ones

Odors that are particularly unpleasant for adults wearing incontinence articles.

Numerous attempts have been made to solve these two problems.

On the one hand, attempts have been made to cover the smell with fragrances, as described in JP-A-0 605 1843, and on the other hand to bind it with zeolites, as described in WO 95/26207. Such measures reduce the perception of uncomfortable Odors, but not the occurrence of skin irritation and inflammation.

Skin irritation occurs frequently when the skin's natural protective acid layer is destroyed. This is done by increasing the pH, for example, by decomposing the urea to ammonia by urease.

EP-A 0 739 635 therefore teaches hydrogels containing sodium tetraborate which act as urease inhibitors.

Furthermore, there are numerous attempts to achieve a skin-neutral pH value with a wide variety of diaper parts by using buffer substances or materials bearing acid groups. EP-A-0 316 518 teaches hydrogels which have a pH of 5.2 to 5.5 when wetted with water. Furthermore, ion-exchanging modified cellulose is described in EP-A-0 202 126 as a covering layer and in EP A-0 202 127 as a core material. All these approaches have in common that the formation of the skin-irritating components is not prevented and the effect wears off with longer contact times.

EP-A-0 837 077, EP-A-0 839 841 and WO 92/06694 describe the use of quaternary ammonium salts such as cetylpyridinium chloride or didecyldimethylamonium carbonate as microbicidal additives for the hydrogel. However, it is disadvantageous that these compounds themselves are not very tolerable to the skin and lead to allergic reactions.

The older German patent application 19926431.7 teaches absorbent mixtures containing organic iodine compounds.

US-A-4 556 560 describes the use of water-soluble metal salts, in particular zinc dichloride, for the treatment of the upper cover layer of a diaper to avoid diaper rash. Furthermore, WO 95/24173 teaches hygiene articles with a liquid-permeable cover which contains zeolites impregnated with heavy metal ions.

WO 98/20915 teaches a superabsorbent composition consisting of a superabsorbent polymer and a zeolite, in which the cations have been replaced by metal cations with microbiocidal properties, in particular with silver ions. When using hygiene articles which contain water-soluble heavy metal salts or zeolites containing heavy metal ions, the heavy metal ions can be extracted very easily by exposure to body fluid, so that direct skin contact cannot be excluded. This can lead to undesirable side effects when wearing such incontinence items daily for long periods, for example in the case of silver to skin discoloration and argyria.

The object was therefore to provide an absorbent preparation which, when used in articles for the absorption of body fluids, enables effective odor control and leaves the skin of the wearer of the article in a healthy state without having the disadvantages mentioned above.

Accordingly, the abovementioned absorbent preparations, their use in hygiene articles and also hygiene articles containing the preparations according to the invention have been found.

Absorbent preparation is to be understood as a preparation that contains a hydrogel-forming polymer as the main component. The preparation according to the invention preferably consists of a silver salt or colloidal silver which is sparingly or insoluble in water, the hydrogel-forming polymer and, if appropriate, additives customary for hydrogel.

Insoluble or sparingly soluble silver salts are understood to mean silver salts which have a solubility product in water at 25 ° C. of less than 1 × 10 ^{~ 8} (mol / L) ^{m + n} (for compounds of the Ag _ra X _{n type} ). Examples of such silver salts are silver bromide, silver chloride, silver iodide, silver molybdate, silver phosphate and silver sulfide. The use of silver chloride is particularly preferred.

The proportion of colloidal silver or the insoluble or sparingly soluble silver salt in the hydrogel-forming polymer is 0.1 to 1000 ppm, preferably 1 to 1000 ppm and particularly preferably 1 to 500 ppm.

Suitable polymers (b) are graft (co) polymers of one or more hydrophilic monomers on a suitable graft base, crosslinked cellulose or starch ethers and starch esters bearing acid groups, crosslinked carboxymethyl cellulose, or natural products with acid groups which are swellable in aqueous liquids, such as for example alginates and carrageenans. Suitable graft bases can be of natural or synthetic origin. Examples are starch, cellulose or cellulose derivatives and other polysaccharides and oligosaccharides, polyvinyl alcohol, polyalkylene oxides, in particular polyethylene oxides and polypropylene oxides, polyamines, polyamides and hydrophilic polyesters. Suitable polyalkylene oxides have, for example, the formula

R ¹ —0— (CH.-CH-O) _, - R ²

wherein

R ¹ and R ² independently of one another are hydrogen, alkyl, alkenyl or aryl,

X is hydrogen or methyl and

n is an integer from 1 to 10,000.

R ¹ and R ^{2 are} preferably hydrogen, (C ₁ -C ₄ ) alkyl, (C ₂ -C ₆ ) alkenyl or phenyl.

Hydrogel-forming polymers (b) are crosslinked polymers with acid groups which are predominantly in the form of their salts, generally alkali metal or ammonium salts. Such polymers swell to form gels on contact with aqueous liquids.

Polymers (b) which are obtained by crosslinking polymerization or copolymerization of monoethylenically unsaturated monomers bearing acid groups or their salts are preferred. It is also possible to (co) polymerize these monomers without crosslinking agents and to crosslink them subsequently.

Such monomers bearing acid groups are, for example, monoethylenically unsaturated C ₃ -C ₅ -carboxylic acids or anhydrides such as acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, and aconitic acid

Fumaric acid. Also suitable are monoethylenically unsaturated sulfonic or phosphonic acids, for example vinylsulfonic acid, allylsulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-acryloxypropanesulfonic acid, 2-hydroxy-3-methacryloxypropanesulfonic acid, vinylphosphonic acid, styllphosphonic acid, allyl sulfonyl acid 2-acrylamido-2-methyl propane sulfonic acid. The monomers can be used alone or as a mixture with one another.

Preferred monomers are acrylic acid, methacrylic acid, vinylsulfonic acid, acrylamidopropanesulfonic acid or mixtures of these acids, e.g. Mixtures of acrylic acid and methacrylic acid, mixtures of acrylic acid and acrylamidopropanesulfonic acid or mixtures of acrylic acid and vinylsulfonic acid.

To optimize properties, it can be useful to use additional monoethylenically unsaturated compounds which do not have an acid group but can be copolymerized with the monomers bearing acid groups. These include, for example, the amides and nitriles of monoethylenically unsaturated carboxylic acids, such as acrylamide, methacrylamide and N-vinylformamide,

N-vinyl acetamide, N-methyl-N-vinyl acetamide, acrylonitrile and methacrylonitrile. Other suitable compounds are, for example, vinyl esters of saturated Cχ ~ to C ₄ carboxylic acids such as vinyl formate, vinyl acetate or vinyl propionate, alkyl vinyl ether with at least 2 C atoms in the alkyl group, such as ethyl vinyl ether or butyl vinyl ether, esters of monoethylenically unsaturated C ₃ - to C _δ Carboxylic acids, for example esters from monovalent C 1 ~ to Cig alcohols and acrylic acid, methacrylic acid or maleic acid, half esters of maleic acid, for example monomethyl maleate, N-vinyl lactams such as N-vinyl pyrrolidone or N-vinyl caprolactam, acrylic acid and methacrylic acid esters of alkoxylated monohydric, saturated Alcohols, for example alcohols with 10 to 25 carbon atoms, which have been reacted with 2 to 200 moles of ethylene oxide and / or propylene oxide per mole of alcohol, and also monoacrylic acid esters and monomethacrylic acid esters of polyethylene glycol or polypropylene glycol, the molar masses (M _N ) of Polyalkylene glycols can be up to 2000, for example. Other suitable monomers are styrene and alkyl-substituted styrenes such as ethylstyrene or tert. Butyl styrene.

These monomers not bearing acid groups can also be used in a mixture with other monomers, e.g. Mixtures of vinyl acetate and 2-hydroxyethyl acrylate in any ratio. These monomers not carrying acid groups are added to the reaction mixture in amounts between 0 and 50% by weight, preferably less than 20% by weight.

Crosslinked polymers from monoethylenically unsaturated monomers bearing acid groups are preferred, which are optionally converted into their alkali metal or ammonium salts before or after the polymerization, and from 0 to 40% by weight, based on their total important monoethylenically unsaturated monomers bearing no acid groups.

Crosslinked polymers (b) of monoethylenically unsaturated C ₃ -C ₂ -carboxylic acids and / or their alkali metal or ammonium salts are preferred. In particular, crosslinked polyacrylic acids are preferred, the acid groups of which are 25-100% in the form of alkali or ammonium salts.

Compounds which have at least 2 ethylenically unsaturated double bonds can function as crosslinkers. Examples of compounds of this type are N, N '-methylene bisacrylamide, polyethylene glycol diacrylates and polyethylene glycol dimethacrylates, which are each derived from polyethylene glycols with a molecular weight of 106 to 8500, preferably 400 to 2000, trimethylol propane triacrylate, trimethylol propane trimethacrylate, ethylene glycol propylene diacrylate, Butanediol diacrylate, butanediol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, allyl methacrylate, diacrylates and dimethacrylates of block copolymers of ethylene oxide and propylene oxide, double or triple esterified with acrylic acid or methacrylic acid, and polyhydric alcohols such as glycerol, triethylammonyldihylammonyldihylammonyldihylammonyldlammonyldlammonyldlammonyldlammonyldlammonyldlammonyldlammonyldl ammonium thylammonyldl ammonium dihydrogenated ammonium diol , Tetraallylethylenediamine, divinylbenzene, diallyl phthalate, polyethylene glycol divinyl ether of polyethylene glycols with a molecular weight of 106 to 4000, trimethylolpropane diallylethe r, butanediol divinyl ether, pentaerythritol triallyl ether, reaction products of 1 mol of ethylene glycol diglycidyl ether or polyethylene glycol diglycidyl ether with 2 mol of pentaerythritol triallyl ether or allyl alcohol and / or divinylethylene urea. Preferably water-soluble crosslinking agents are used, e.g. N, N '-methylene bisacrylamide, polyethylene glycol diacrylates and polyethylene glycol dimethacrylates derived from addition products of 2 to 400 moles of ethylene oxide with 1 mole of a diol or polyol, vinyl ethers of addition products with 2 to 400 moles of ethylene oxide with 1 mole of a diol or polyol, ethylene glycol diacrylate , Ethylene glycol dimethacrylate or triacrylate and trimethacrylates of addition products of 6 to 20 moles of ethylene oxide with 1 mole of glycerol, pentaerythritol triallyl ether and / or divinyl urea.

Also suitable as crosslinkers are compounds which contain at least one polymerizable ethylenically unsaturated group and at least one further functional group. The functional group of these crosslinkers must be able to react with the functional groups, essentially the acid groups of the monomers. Suitable functional groups are for example hydroxyl, amino, epoxy and aziridino groups. For example, hydroxyalkyl esters of the above-mentioned monoethylenically unsaturated carboxylic acids, such as 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl methacrylate, allyl piperidinium bromide, N-vinyl imidazole such as N-vinyl imidazole such as N-vinyl imidazole -methylimidazole and N-vinylimidazolines such as N-vinylimidazoline, l-vinyl-2-methylimidazoline, l-vinyl-2-ethyl-imidazoline or l-vinyl-2-propylimidazoline, which are in the form of the free bases, in quaternized form or as a salt can be used in the polymerization. Also suitable are dialkylaminoethyl acrylates and dialkylaminoethyl methacrylates, such as dirnethylaminoethyl acrylate, dirnethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoethyl methacrylate. The basic esters are preferably used in quaternized form or as a salt. Glycidyl (meth) acrylate can also be used, for example.

Also suitable as crosslinkers are compounds which contain at least two functional groups which are capable of reacting with the functional groups of the polymers, essentially the acid groups.

The suitable functional groups are hydroxyl, amino, epoxy, isocyanate, ester, amido and aziridino groups. Examples of such crosslinking agents are ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, polyglycerol, triethanolamine, propylene glycol, polypropylene glycol, block copolymers of ethylene oxide and propylene oxide, ethanolamine, sorbitan fatty acid esters, ethoxylated sorbitan fatty acid, 3-sorbitan fatty acid, 3-sorbitan fatty acid, 3-sorbitan fatty acid, 3-sorbitan fatty acid, butanediol, 1, 4-butanediol, polyvinyl alcohol, sorbitol, starch, polyglycidyl ethers such as ethylene glycol, Polyethylenglykoldiglyci - dylether, glycerol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan bitpolyglycidylether, pentaerythritol polyglycidyl ether, propylene glykoldiglycidylether and polypropylene glycol diglycidyl ether, polyaziridine compounds such as 2, 2- Bishydroxymethylbutanol-tris [3- (1-aziridinyl) propionate], 1,6-hexamethylene-diethylene urea, diphenylmethane-bis-4,4'-N, N '-diethylene urea, halo-epoxy compounds such as epichloro ydrin and α-methylepifluorohydrin, polyisocyanates such as 2, 4-tolylene diisocyanate and hexamethylene diisocyanate, alkylene carbonates such as 1, 3-dioxolan-2-one and 4-methyl-l, 3-dioxolan-2-one, furthermore bisoxazolines and oxazoli- do , Polyamidoamines and their reaction products with epichlorohydrin, also polyquaternary amines such as condensation products of dimethylamine with epichlorohydrin, homo- and copolymers of Diallyldimethylammonium chloride and homo- and copolymers of

Dirnethylaminoethyl (meth) acrylate, which are optionally quaternized with, for example, methyl chloride.

Other suitable crosslinkers are polyvalent metal ions, which are able to form ionic crosslinks. Examples of such crosslinkers are magnesium, calcium, barium and aluminum ions. These crosslinkers are used, for example, as hydroxides, carbonates or hydrogen carbonates. Other suitable crosslinkers are multifunctional bases which are also able to form ionic crosslinks, for example polyamines or their quaternized salts. Examples of polyamines are ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine and polyethyleneimines and polyamines with molecular weights of up to 4,000,000 each.

The crosslinkers are present in the reaction mixture, for example from 0.001 to 20% by weight and preferably from 0.01 to 14% by weight.

The polymerization is initiated as usual by an initiator. It is also possible to initiate the polymerization by the action of electron beams on the polymerizable, aqueous mixture. However, the polymerization can also be initiated in the absence of initiators of the type mentioned above by the action of high-energy radiation in the presence of photoinitiators. All compounds which decompose into free radicals under the polymerization conditions can be used as polymerization initiators, for example peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds and the so-called redox catalysts. The use of water-soluble initiators is preferred. In some cases it is advantageous to use mixtures of different polymerization initiators, for example mixtures of hydrogen peroxide and sodium or potassium peroxodisulfate. Mixtures of hydrogen peroxide and sodium peroxodisulfate can be used in any ratio. Suitable organic peroxides are, for example, acetylacetone peroxide, methyl ethyl ketone peroxide, tert-butyl hydroperoxide, cumene hydroperoxide, tert. -Amyl perpivalate, tert-butyl perpivalate, tert. Butyl perneohexanoate, tert. -Butylperisobuty- rat, tert. -Butyl-per-2-ethylhexanoate, tert-butyl perisononanoate, tert-butyl permaleate, tert. -Butyl perbenzoate, di- (2-ethylhexyl) peroxidicarbonate, dicyclohexylperoxydicarbonate, di- (4-tert.-butylcyclohexyl) peroxydicarbonate, di yristilperoxydicarbonate, diacetylperoxydicarbonate, allyl peresters, cumylperoxyneodecanoate. -Butylper-3, 5, 5-trimethylhexanoate, acetylcyclohexylsulfonyl peroxide, dilauryl peroxide, dibenzoyl peroxide and tert. -Amylperneo decanoate. Particularly suitable polymerization initiators are * vo

C

* <

Φ g

P Φ c

P ω

D P> rr φ o

> D p

Φ tr

Φ

P H φ

P o tr

P> φ

P ω

P g o P

P P o rr

Φ Φ π- P tr

^ 3

O

P

P O

Φ rr o tr T • <; c

P P

<D ω o tr

P rr Φ

Φ

P p): rr π rr o g o

P o P

were produced and which have a molecular weight greater than 5000, preferably greater than 50,000, reacted with compounds which have at least two groups which are reactive toward acid groups. The suitable functional groups and examples have already been listed above. This reaction can take place at room temperature or at elevated temperatures up to 220 ° C.

Furthermore, the above-mentioned polyvalent metal ions, which can form ionic bonds, and the above-mentioned multifunctional bases, which likewise bring about crosslinking via ionic bonds, are suitable for the subsequent crosslinking.

The crosslinkers are added to the acid-bearing polymers or their salts in amounts of 0.5 to 25% by weight, preferably 1 to 15 15% by weight, based on the amount of the polymer used.

The crosslinked polymers (b) are preferably used in neutralized form in the mixture according to the invention. However, the neutralization can also have been carried out only partially. The degree of neutralization is preferably 25 to 100%, in particular 50 to 100%. Possible neutralizing agents are:

Alkali metal bases or ammonia or amines. 25 sodium hydroxide solution or potassium hydroxide solution is preferably used. However, the neutralization can also be carried out with the aid of sodium carbonate, sodium hydrogen carbonate, potassium carbonate or potassium hydrogen carbonate or other carbonates or hydrogen carbonates or ammonia. Furthermore, prim. , sec. and tert. Amines can be used. 30

All processes which are usually used in the production of superabsorbers, such as are used, for example, can be used as technical processes for producing these products. in Chapter 3 in "Modern Superabsorbent Polymer Technology", 35 F.L. Buchholz and A.T. Graham, Wiley-VCH, 1998.

Polymerization in aqueous solution is preferred as so-called gel polymerization. 10 to 70% by weight aqueous solutions of the monomers and optionally a suitable graft base are polymerized in the presence of a radical initiator using the Trommsdorff-Norrish effect.

The polymerization reaction can be carried out in the temperature range from 0 to 150.degree. C., preferably from 10 to 100.degree. C., both under normal pressure and under 5 and under elevated or reduced pressure. As usual, the polymerization can also be carried out in a protective gas atmosphere, preferably under nitrogen.

The quality properties of the polymers can be improved further by reheating the polymer gels for several hours in the temperature range from 50 to 130 ° C., preferably 70 to 100 ° C.

Hydrogel-forming polymers (b) which are post-crosslinked are preferred. The surface postcrosslinking can take place in a manner known per se with dried, ground and sieved polymer particles.

For this purpose, compounds which can react with the functional groups of the polymers (b) with crosslinking are preferably applied to the surface of the hydrogel particles in the form of a water-containing solution. The water-containing solution can contain water-miscible organic solvents. Suitable solvents are alcohols such as methanol, ethanol, i-propanol or acetone.

Suitable post-crosslinking agents are, for example

Di- or polyglycidyl compounds such as phosphonic acid diglycidyl ether or ethylene glycol diglycidyl ether, bischlorohydrin ether of polyalkylene glycols,

alkoxysilyl

Polyaziridines, compounds containing aziridine units based on polyethers or substituted hydrocarbons, for example bis-N-aziridinomethane,

Polyamines or polyamidoamines and their reaction products with epichlorohydrin,

- Polyols such as ethylene glycol, 1, 2-propanediol, 1, 4-butanediol, glycerol, methyltriglycol, polyethylene glycols with an average molecular weight M _w of 200-10000, di- and polyglycerol, pentaerythritol, sorbitol, the oxyethylates of these polyols and their Esters with carboxylic acids or carbonic acid such as ethylene carbonate or propylene carbonate,

Carbonic acid derivatives such as urea, thiourea, guanidine, dicyandiamide, 2-oxazolidinone and its derivatives, bisoxazoline, polyoxazolines, di- and polyisocyanates, Di- and poly-N-methylol compounds such as methylenebis (N-methylol-methacrylamide) or melamine-formaldehyde resins,

- Compounds with two or more blocked isocyanate groups such as trimethylhexamethylene diisocyanate blocked with 2,2,3,6-tetramethyl-piperidinone-4.

If necessary, acidic catalysts such as p-toluenesulfonic acid, phosphoric acid, boric acid or ammonium dihydrogen phosphate can be added.

Particularly suitable post-crosslinking agents are di- or polyglycidyl compounds such as ethylene glycol diglycidyl ether, the reaction products of polyamidoamines with epichlorohydrin and 2-oxazolidinone.

The crosslinker solution is preferably applied by spraying on a solution of the crosslinker in conventional reaction mixers or mixing and drying systems such as Patterson-Kelly mixers, DRAIS turbulence mixers, Lödige mixers, screw mixers, plate mixers, fluidized bed mixers and Schugi mix. After spraying on the crosslinking agent solution, a temperature treatment step can follow, preferably in a downstream dryer, at a temperature between 80 and 230 ° C, preferably 80-190 ° C, and particularly preferably between 100 and 160 ° C, over a period of 5 minutes up to 6 hours, preferably 10 minutes to 2 hours and particularly preferably 10 minutes to 1 hour, it being possible for both cleavage products and solvent fractions to be removed. However, drying can also take place in the mixer itself, by heating the jacket or by blowing in a preheated carrier gas.

In a particularly preferred embodiment of the invention, the hydrophilicity of the particle surface polymer (b) is additionally modified by the formation of complexes. The complexes are formed on the outer shell of the hydrogel particles by spraying on solutions of divalent or polyvalent metal salt solutions, the metal cations being able to react with the acid groups of the polymer to form complexes. Examples of divalent or polyvalent metal cations are Mg ²⁺ , Ca ²⁺ , Al ³⁺ , Sc ³⁺ , Ti ⁺ , Mn ⁺ , Fe ²⁺ / ³⁺ , Co ²⁺ , Ni ²⁺ , Cu ⁺ / ⁺ , Zn ²⁺ , Y ³⁺ , Zr ⁺ , Ag ⁺ , La ³⁺ , Ce ⁴⁺ , Hf ⁺ , and Au ⁺ / ³⁺ , preferred metal cations are Mg ²⁺ , Ca ²⁺ , Al ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ and La ³⁺ , and particularly preferred metal cations are Al ³⁺ , Ti ⁴⁺ and Zr ⁴⁺ . Of the metal cations mentioned, all salts are suitable which have sufficient solubility in the solvent to be used. As a solvent for the Salts can be water, alcohols, DMF, DMSO and mixtures of these components. Water and water / alcohol mixtures such as water / methanol or water / 1, 2-propanediol are particularly preferred.

The salt solution can be sprayed onto the particles of the hydrogel-forming polymer both before and after the surface post-crosslinking of the particles. In a particularly preferred method, the salt solution is sprayed on in the same step as the spraying of the crosslinking agent solution, with both solutions being sprayed on separately in succession or simultaneously via two nozzles, or the crosslinking agent and salt solution being sprayed together via a nozzle.

Optionally, a further modification of the particles of polymer (b) can be carried out by admixing finely divided inorganic solids, such as, for example, silica, bentonite, aluminum oxide, titanium dioxide and iron (II) oxide, which further enhances the effects of surface treatment. The addition of hydrophilic silica or of is particularly preferred

Aluminum oxide with an average primary particle size of 4 to 50 nm and a specific surface area of 50-450 m ² / g. Fine inorganic solids are preferably added after the surface modification by crosslinking / complex formation, but can also be carried out before or during these surface modifications.

Colloidal silver or the insoluble or sparingly soluble silver salt can be introduced into the hydrogel-forming polymer in various ways. For example, colloidal silver or the insoluble or sparingly soluble silver salts can be added to the monomer solution before the polymerization, or the addition takes place at any time during the preparation of the hydrogel-forming polymer, for example during or after the polymerization. It is also possible to apply colloidal silver or insoluble or sparingly soluble silver salts to the already dried hydrogel-forming polymer particles, for example by spraying on an emulsion or dispersion which contains colloidal silver or insoluble or sparingly soluble silver salts, or by addition Corresponding emulsions or dispersions to the surface postcrosslinker solution to be applied to the hydrogel particles. Furthermore, it is also possible to add colloidal silver or insoluble or sparingly soluble silver salts to the hydrogel by means of a powder mixture. The resulting hydrogel-forming polymer contains the colloidal silver or the insoluble or sparingly soluble silver salts, depending on the time of addition, evenly distributed or reinforced on its surface. Hydrogel whose surface has been treated with colloidal silver or insoluble or sparingly soluble silver salts is particularly preferred.

In a preferred embodiment of the invention, an insoluble or sparingly soluble silver salt is used, which is located on an inert carrier material. Inert here is understood to mean that the carrier material does not form, swell or even dissolve in contact with water or aqueous solutions. The carrier material is preferably oxidic in nature, ie it is an oxide, a hydroxide or contains oxy anions such as sulfate or phosphate. Examples of such materials are the oxides of titanium, magnesium, aluminum, silicon, cerium, zirconium, hafnium, niobium and tantalum, calcium hydroxyapatite and barium sulfate. Titanium dioxide and silicon dioxide are particularly preferred. The particle size of the inert carrier material is less than 500 μm, preferably less than 100 μm, and is particularly preferably in the range from 1 to 15 μm. The specific surface area of the inert carrier material is at least 1 g / m ² , preferably at least 5 g / m ² and is particularly preferably in the range from 5 to 100 g / m ² . The content of sparingly soluble or insoluble silver salt on the inert carrier material is 0.1-90% by weight, based on the carrier material, and preferably 10-60% by weight. Silver chloride is preferably used as the insoluble or poorly soluble silver salt.

In a further preferred embodiment of the invention, the hydrogel-forming polymer contains, in addition to colloidal silver or an insoluble or sparingly soluble silver salt, a nonionic, anionic, cationic or amphoteric surfactant with an HLB value greater than or equal to 3 (definition of the HLB value: see WC Griffin, J. Soc. Cosmetic Chem. 5 (1954) 249). Preferred surfactants are those which are soluble or at least dispersible in water.

Suitable nonionic surfactants are, for example, the addition products of ethylene oxide, propylene oxide or mixtures of ethylene oxide and propylene oxide with alkylphenols, aliphatic alcohols, carboxylic acids and amines. For example, Cs-Cχ-alkylphenols alkoxylated with ethylene oxide and / or propylene oxide are suitable. Commercial products of this type are, for example, octylphenols or nonylphenols, which are each reacted with 4 to 20 moles of ethylene oxide per mole of phenol. Other nonionic surfactants are ethoxylated C ₁₀ -C ₂₄ fatty alcohols or ethoxylated Cio to C ₂ fatty acids as well as ethoxylated Cχo C ₂₄ fatty amines or ethoxylated C ₁ -C ₂ fatty acid amides. In addition, partially esterified with C 1 -C ₂₄ -fatty acids are polyhydric C ₃ - to C ₆ -alcohols. These esters can additionally be reacted with 2 to 20 moles of ethylene oxide. Suitable fatty alcohols which are alkoxylated to produce the surfactants are, for example

Palmityl alcohol, stearyl alcohol, myristyl alcohol, lauryl alcohol, oxo alcohols and unsaturated alcohols such as oleyl alcohol. The fatty alcohols are ethoxylated or propoxylated to such a degree or reacted with ethylene oxide and propylene oxide that the reaction products are soluble in water. In general, 1 mol of the above-mentioned fatty alcohols is reacted with 2 to 20 mol of ethylene oxide and optionally up to 5 mol of propylene oxide in such a way that surfactants are obtained which have an HLB value of more than 8.

C - to Cβ-alcohols which are partially esterified and optionally ethoxylated are, for example, glycerol, sorbitol, mannitol and pentaerythritol. These polyhydric alcohols are partially esterified with Cχo to C ₂₄ fatty acids, such as oleic acid, stearic acid or palmitic acid. The esterification with the fatty acids takes place at most to such a degree that at least one OH group of the polyhydric alcohol remains unesterified. Suitable esterification products are, for example, sorbitan mono-oleate, sorbitan tristearate, manit monooleate, glycerol onooleate and glycerol dioleate. The fatty acid esters of polyhydric alcohols mentioned, which still contain at least one free OH group, can also be reacted with ethylene oxide, propylene oxide or mixtures of ethylene oxide and propylene oxide for modification. 2 to 20 moles of the alkylene oxides mentioned are preferably used per mole of fatty acid ester. As is known, the degree of ethoxylation has an influence on the HLB value of the nonionic surfactants. By suitable choice of the alkoxylating agent and the amount of alkoxylating agent, surfactants with HLB values in a range from 3 to 20 can be produced in a technically simple manner.

Another group of suitable substances are homopolymers of ethylene oxide, block copolymers of ethylene oxide and alkylene oxides, preferably propylene oxide, and polyfunctional block copolymers which are formed, for example, by sequential addition of propylene oxide and ethylene oxide to diamines.

Also suitable are alkyl polyglycosides, such as those marketed by Henkel as APG®, Glucopan® and Plantaren®. The nonionic surfactants can be used either alone or in a mixture with one another.

Suitable anionic surfactants are C ₈ to C ₂₄ alkyl sulfonates, which are preferably used in the form of the alkali salts, C _B to C ₂₄ alkyl sulfates, which are preferably used in the form of the alkali metal or trialkanol ammonium salts, such as triethanolammonium lauryl sulfate, Sulfosuccinic acid diesters, for example the sodium salt of sulfosuccinic acid di (2-ethylhexyl) ester or sodium dioctyl sulfosuccinate, sulfosuccinic acid semiesters, such as, for example

Sodium lauryl sulfosuccinate or disodium fatty alcohol polyglycol ether sulfosuccinate, Cs to C ₂ alkylarylsulfonic acids and the sulfuric acid semiesters of adducts of ethylene oxide with alkylphenols or fatty alcohols.

Examples of suitable cationic surfactants are the salts of fatty amines, for example coconut fat ammonium acetate, quaternary fatty acid amino esters, for example isopropyl difatty acid dimethylammonium methosulfate, quaternary fatty acid aminoamides, for example N-undecylenic acid propylamino-N-trimethylammonidene anoxides of fatty amines and salamino methylene sulfates, or , such as pentoxethylstearylammonium acetate or ethoxylated methyloleinamine methosulfate and long-chain alkylbenzyldimethylammonium compounds, such as C ₀ - to C ₂₂ alkylbenzyldimethylammonium chloride.

Examples of suitable amphoteric surfactants are compounds which carry at least one quaternary ammonium cation and at least one carboxylate or sulfate anion in the same molecule, such as dimethylcarboxymethyl fatty acid alkylamidoammonium betaines or 3- (3-fatty acid amidopropyl) dimethylammonium 2-hydroxypropane sulfonates.

The ionic surfactants can be used alone or as a mixture with one another.

The surfactants are used in amounts of 0.0001 to 5% by weight, preferably 0.01 to 2.5% by weight, based on the hydrogel-forming polymer. The use of sulfosuccinates such as sodium dioctyl sulfosuccinate or sodium lauryl sulfosuccinate is preferred. Similar to colloidal silver or the insoluble or poorly soluble silver salts, the surfactant can be incorporated into the hydrogel-forming polymer.

In a further preferred embodiment of the invention, the hydrogel-forming polymer contains, in addition to colloidal silver or insoluble or sparingly soluble silver salts and optionally surfactants, additives with fungicidal properties. Suitable additives are, for example, 3-iodo-2-propynyl butyl carbamate, Diidomethyl-p-tolyl sulfone, 2,4,4 'trichloro-2' hydroxydiphenyl ether and 2-bromo-2-nitro-1,3-propanediol. The use of 3-iodo-2-propynyl butyl carbamate is particularly preferred.

The additives are used in amounts of 1 to 10,000 ppm, preferably 10 to 1000 ppm, based on the hydrogel-forming polymer. The additives can be introduced into the hydrogel-forming polymer in a manner similar to colloidal silver or the insoluble or poorly soluble silver salt.

The pH of the absorbent preparation according to the invention is in the range from 3 to 7, preferably from 4 to 6 and particularly preferably from 4.5 to 6.

The absorbent preparations according to the invention have good fungicidal and bactericidal properties. The hygiene articles containing them show good skin tolerance.

Furthermore, the present invention relates to comprehensive hygiene articles

(A) an upper liquid permeable cover

(B) a lower liquid impervious layer

(C) containing a core located between (A) and (B)

(Cl) 10-100% by weight of the absorbent preparation according to the invention

(C2) 0 - 90% by weight of hydrophilic fiber material

(D) optionally a tissue layer located immediately above and below the core (C) and

(E) optionally a receiving layer located between (A) and (C).

Hygiene articles mean both incontinence pads and incontinence pants for adults and diapers for babies.

The liquid-permeable cover (A) is the layer that has direct skin contact. The material is conventional synthetic and semi-synthetic fibers or films such as polyester, polyolefins, rayon or natural fibers such as cotton. With non-woven materials, the fibers are in the Usually linked by binders such as polyacrylates. Preferred materials are polyester, rayon and their blends, polyethylene and polypropylene.

The liquid-impermeable layer (B) generally consists of a film made of polyethylene or polypropylene.

In addition to the mixture (Cl) according to the invention, the core (C) contains hydrophilic fiber material (C2). Hydrophilic is understood to mean that aqueous liquids are quickly distributed over the fiber. Usually the fiber material is cellulose, modified cellulose, rayon, polyester such as polyethylene terephthalate. Cellulose fibers such as cellulose are particularly preferred. The fibers usually have a diameter of 1 - 200 μm, preferably 10 - 100 μm. In addition, the fibers have a minimum length of 1 mm.

The proportion of the hydrophilic fiber material based on the total amount of the core is preferably 20-80% by weight, particularly preferably 40-70% by weight.

The structure and shape of diapers is generally known and is described, for example, in EP-A-0 316 518 and EP-A-0 202 127.

The following examples are intended to explain the invention in more detail.

Description of the test methods:

Measurement of the pH value:

100 ml of 0.9% by weight NaCl solution was stirred in a 150 ml beaker with a magnetic stirrer at a moderate speed without air being drawn into the solution. To this solution was added 0.5 + 0.001 g of absorbent mixture and stirred for 10 minutes. After 10 minutes, the pH of the solution was measured using a pH glass electrode, the value being read only when it was stable, but at the earliest after 1 minute.

Determination of the microbicidal effectiveness:

1 g absorbing mixture was mixed with 100 ml synthetic urine replacement solution and 0.1 ml germ solution (approx. 1 - 5 x 10 ⁸ CFU per ml germ suspension) was added. The synthetic urine replacement solution contained 0.64 g CaCl ₂ , 1.14 g MgSO ₄ × 7 H ₂ O, 8.20 g NaCl and 20.0 g urea per 1000 ml demineralized water. The contaminated Test solution was incubated at 37 ° C. with shaking at 100 rpm in a water bath. At 0 minutes, after 6 and 23 hours, 10 ml of contaminated test solution were mixed with 90 ml of caso broth and inactivating substances. 1 ml of the inactivation broth 5 is mixed with Caso agar and 0.1 ml of the inactivation broth is spatulated out on Caso agar + HLT.

example 1

10 In a well insulated by foamed plastic material

3600 g of demineralized water and 1400 g of acrylic acid were placed in a polyethylene vessel with a capacity of 10 l. Now 7.5 g of tetraallyloxyethane were added. At a temperature of 4 ° C 2.2 g of 2,2'-azobisamidinopropane dihydrochloride were dissolved in

15 20 g of deionized water, 4 g of potassium peroxodisulfate, dissolved in 150 g of deionized water and 0.4 g of ascorbic acid, dissolved in 20 g of deionized water, were added in succession and stirred. The reaction solution was then left to stand without stirring, with the onset of polymerization, in the course of which the temperature rose to

20 rose to approx. 92 ° C, a firm gel formed. This was then mechanically crushed and adjusted to a pH of 5.3 by adding 25% sodium hydroxide solution. The gel was then dried, ground and sieved to a particle size distribution of 100-850 μm. 1 kg of this dried

25 hydrogel was sprayed in a plowshare mixer with a solution consisting of 25 g deionized water, 40 g of methanol and 20 of a 15 wt .-% w aqueous solution of a polyamidoamine-epichlorohydrin adduct (RETEN ^® 204 LS of Messrs. Hercules) and then annealed at 140 ° C for 60 minutes. After cooling

In addition, the product in the ploughshare mixer was sprayed with a mixture of 50 ppm silver protein (Aldrich, mild silver protein, colloidal silver, approx. 20% Ag) and 2.5% by weight of deionized water, based in each case on the polymer. The microbicidal effectiveness of the product described here was

35 determined (Table 1):

Table 1: Content of colony-forming units (CFU) per ml test solution depending on the incubation period

40

45

Example 2

14340 g of demineralized water and 30 g of pentaerythritol triallyl ether were placed as a copolymerization crosslinker in a polyethylene vessel with a capacity of 30 l, which was well insulated by foamed plastic material, 5170 g of sodium bicarbonate were suspended therein and 5990 g of acrylic acid were slowly metered in so that the reaction solution was not over-foamed, resulting in this cooled to a temperature of approx. 3 - 5 ° C. 6.0 g of 2,2′-azobisamidinopropane dihydrochloride, dissolved in 60 g of demineralized water, 12 g of potassium peroxodisulfate, dissolved in 450 g of demineralized water and 1.2 g of ascorbic acid, were dissolved at a temperature of 4.degree in 50 g of demineralized water, added in succession and stirred well. The reaction solution was then left to stand without stirring, a gel resulting from the onset of polymerization, in the course of which the temperature rose to approximately 85 ° C. This was then transferred to a kneader, mixed with 6.0 g of JM ActiCare ™ (from Johnson Matthey PLC, contains 2% silver chloride, 8% titanium dioxide and 5-25% sodium dioctyl sulfosuccinate) and 500 g of deionized water, homogeneously kneaded, crushed, dried, ground and sieved. 1 kg of this product was sprayed in a ploughshare mixer with a solution of 2 g of polyglycerol polyglycidyl ether (Denacol CK) EX-512 from Nagase Chemicals Ltd.), 0.3 g of citric acid, 40 g of demineralized water and 60 g of 1,2-propanediol and then annealed at 150 ° C for 40 minutes. The microbicidal activity of the product described here, which has a pH of 6.0, can be seen in Table 2.

Table 2: Content of colony-forming units (CFU) per ml test solution depending on the incubation period

Example 3

The procedure was as in Example 2, but an additional 0.02% by weight of the additives listed in Table 3 was added to the postcrosslinker solution. The microbicidal activity of the products is shown in Table 3.

Table 3: Content of colony-forming units (CFU) per ml test solution depending on the incubation period

Comparative Example 1

The procedure was as in Example 1, but the product was not sprayed with a silver protein emulsion. The microbicidal activity of the product is shown in Table 4.

Table 4: Content of colony-forming units (CFU) per ml test solution depending on the incubation period

Comparative Example 2

The procedure was as in Example 2, but the suspension was not mixed with the silver chloride. The microbicidal activity of the product is shown in Table 5.

Table 5: Content of colony-forming units (CFU) per ml test solution depending on the incubation period

In contrast to the polymers obtained in the comparative examples, the hydrogel-forming polymers obtained according to Examples 1 to 3 are distinguished by excellent microbicidal activity and are therefore excellent as absorbents for water and aqueous liquids, in particular body fluids, such as e.g. Urine or blood, suitable for example in hygiene articles such as Baby and adult diapers, sanitary napkins, tampons and the like.

Claims

claims

1. Absorbent preparation containing

(b) a hydrogel-forming polymer,

the proportion of silver being 0.1 to 1000 ppm of the hydrogel-forming polymer.

2. Absorbent preparation according to claim 1, consisting of

(b) a hydrogel-forming polymer

and optionally additives customary for hydrogel.

3. Absorbent preparation according to claim 1 or 2, characterized in that the hydrogel-forming polymer is a crosslinked polymer composed of monoethylenically unsaturated monomers bearing acid groups, which are optionally converted into their alkali metal or ammonium salts before or after the polymerization, and 0 - 40% by weight, based on its total weight, of monoethylenically unsaturated monomers bearing no acid groups.

4. Absorbent preparation according to claims 1 to 3, characterized in that the hydrogel-forming polymer is a crosslinked polymer of monoethylenically unsaturated C ₃ -C ₂ - carboxylic acids and / or their alkali metal or ammonium salts.

5. Absorbent preparation according to claims 1 to 4, characterized in that the surface of the hydrogel-forming polymer has been treated with a silver salt or colloidal silver which is difficult or insoluble in water.

6. Absorbent preparations according to claims 1 to 5, characterized in that the sparingly or insoluble silver salt is on an inert carrier material.

7. Absorbent preparation according to claims 1 to 6, characterized in that it contains a nonionic, anionic, cationic or amphoteric surfactant with an HLB value> 3.

8. Absorbent preparation according to claims 1 to 7, characterized in that it contains a fungicidal additive.

9. Use of silver salts which are sparingly or insoluble in water or colloidal silver in hygiene articles.

10. Use of absorbent preparations according to claims 1 to 8 in hygiene articles.

11. Comprehensive hygiene items

(A) an upper liquid permeable cover

(B) a lower liquid impervious layer

(C) containing a core located between (A) and (B)

(CD 10-100% by weight of an absorbent preparation according to claims 1-8

(C2) 0 - 90% by weight of hydrophilic fiber material

(E) optionally a receiving layer located between (A) and (C).