RU2423999C2 - Absorbent product containing organic zinc salt and antibacterial agent, or alkaline metal chloride or alkaline-earth metal chloride - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: present invention refers to an absorbent product, such as a draw sheet, a diaper, hygienic napkins or incontinence devices, including a protective sheet, a back sheet and an absorbent inner layer between said protective sheet and said back sheet where said absorbent inner layer contains alkaline or alkaline-earth metal chloride combined with an organic zinc salt, particularly zinc ricinoleate.

EFFECT: combination of alkaline (earth) metal chloride and the organic zinc salt promotes a synergistic effect for elimination of an unpleasant smell, such as ammonia.

11 cl, 1 tbl, 3 ex

Description

The present invention relates to an absorbent article, such as a diaper, diaper, sanitary napkin or incontinence product, including an effective deodorizing system. The present invention relates in particular to such absorbent articles, where an organic zinc salt, such as zinc ricinoleate, and an antibacterial agent or alkali metal chloride or alkaline earth metal chloride interact with the reduction of an unpleasant odor such as ammonia.

BACKGROUND OF THE INVENTION

One important development challenge in the field of absorbent products of the aforementioned type is the control of odorous substances, usually formed after the release of body fluids, especially over a long period of time. Such compounds include fatty acids, ammonia, amines, sulfur compounds, and ketones and aldehydes. They are present as natural constituents of body fluids or are formed as a result of decomposition of natural ingredients such as urea, which is often facilitated by microorganisms living in the flora of the urogenital tract.

To suppress the formation of unpleasant odors in absorbent products, there are various approaches. WO97 / 46188, WO 97/46190, WO 97/46192, WO 97/46193, WO 97/461195 and WO 97/46196 describe, for example, the inclusion of odor-inhibiting additives or deodorants, such as zeolites and silica. However, the absorption of body fluids reduces the ability of zeolites to inhibit odor when saturated with water, as mentioned, for example, in WO 98/17239.

The second approach involves the addition of lactic acid bacteria to the product in order to suppress the bacteria forming an unpleasant odor. The inclusion of lactic acid bacteria and their beneficial effects are described, for example, in SE 9703669-3, SE 9502588-8, WO 92/13577, SE 9801951-6 and SE 9804390-4.

Another approach is the use of partially neutralized superabsorbent materials (acidic superabsorbent materials) (see WO 98/57677, WO 00/35503 and WO 00/35505).

Therefore, in the technical field there is a continuing need for effective deodorizing systems in absorbent products. In particular, it is desirable to provide a deodorizing system that provides an effective odor reduction while maintaining the bacterial flora in the urogenital region.

US 2006/0036223 and US 2006/0036222 describe absorbent articles including substances that modify body exudates, skin care compositions, and neutralizers of substances that modify body exudates. The latter can be an inhibitor of enzymes, which can be selected from a large group of compounds, including zinc salts of saturated and unsaturated monocarboxylic acids. Optionally, skin care compositions include an additional ingredient selected from the group consisting of, among many other members, preservatives, antimicrobial agents, and antifungal agents. The solutions disclosed in US 2006/0036223 and US 2006/0036222 are intended to reduce the viscosity of body exudates to facilitate absorption of exudates in an absorbent article. Odor reduction is not a consideration.

EP-A-165074 describes a hydrophilic polymer material, for example, for the production of sanitary napkins and diapers. A hydrophilic polymer material can be obtained by a process in which a specific hydrogel is dried and can be brought into contact with an aqueous solution. In addition to electrolytes, nutrients, physiologically active polypeptides and proteins, the aqueous solution may also contain antibacterial agents. Moreover, zinc ions can be included in the hydrogel, for example, in the form of zinc sulfate or a salt of an acidic amino acid. Indicate that zinc ions have a beneficial effect on cell growth. The odor reduction problem in this link has not been resolved.

Bacteriostatic, bactericidal and antifungal compositions disclosed in EP-A-0366869 include lysozyme, a mineral component and an immunomodulating agent. The mineral component, which has been found to enhance the mycobactericidal effect of lysozyme, may include zinc and / or iodine (Clause 5). Zinc can be presented in the form of zinc sulfate, zinc oxide, zinc gluconate and other salts and compounds of zinc. The immunomodulatory agent contained in the composition may be selected, among many others, from benzoic acid.

US 5721295 and US 5847031 relate to absorbent polymer compositions comprising an ionic or covalent crosslinking agent. The ionic crosslinking agent may be a metal compound selected from the group consisting of water-soluble compounds of magnesium, calcium, aluminum, zirconium, iron and zinc (see paragraphs 6 and 21 of D8a; and paragraphs 6 and 19 of D8b). Zinc compounds may be salts of inorganic acids or carboxylic acids. A lot of suitable covalent crosslinking agents, among which citric acid, are mentioned in the link. US 5721295 and US 5847031, in addition, describe a composition containing an active substance, comprising a composition of an absorbent polymer and at least one active substance, which can be selected from the group consisting of drugs, pesticides, bactericidal substances and flavorings. Reference documents focused on biodegradability, and odor reduction was not the issue under consideration.

US 6015547 relates to a pure and storage-stable aqueous or aqueous / alcoholic solution of zinc ions in the presence of at least one bicarbonate and carbonate ions. The solution includes the zinc salt of the first anion. Optionally, the solution may contain antibacterial agents. The essence of the patent consists in combining compounds containing zinc ion and compounds containing bicarbonate and / or carbonate ion, each of which is in solution, i.e. without the release of carbon dioxide and without the formation of insoluble basic salts of zinc and carbonate.

Products for applying to the skin of skin care compositions in accordance with US 6153209 may include a skin care substance, which, among a large number of compounds, may be zinc acetate. Antibacterial active ingredients are mentioned in a long list of additional ingredients. However, reference does not imply any effect on odor reduction using a combination of an organic zinc salt such as zinc acetate and a preservative.

US 7005557; US 2003/0077307 and US 2006/0064068 relate to articles, in particular disposable absorbent articles having film-forming compositions comprising a viscosity enhancer and, optionally, antimicrobial agents (selected from a very large group). The documents provide a very long list of viscosity enhancers, including complexes of metal, aluminum, magnesium or zinc esters with stearates, behenates, palmitates or laurinates. The task of these documents is not to reduce odor, but to form a protective barrier for liquids, body exudates and other irritants.

The extremely swellable absorbent medium disclosed in US 2004/0213892 includes at least one Lewis acid as a coating agent. Provide a large number of suitable Lewis acids, including benzoic acid, citric acid and water-soluble acetates, formats, oxalates or lactates, among other things zinc. However, the document does not describe a preservative in combination with an organic zinc salt. Moreover, the objective of US 2004/0213892 is to reduce the tendency to caking in a humid environment and / or at high temperature, while reducing odor is not a consideration.

US 2005/0101927 relates to moisturizing and lubricating compositions that can be used on absorbent products. Absorbent products include an immobilizing substance. Many suitable compounds are indicated as suitable immobilizing agents, including zinc stearate. While preservatives are optionally added, odor reduction is not a consideration.

WO 99/00090 relates to a colostomy bag which includes a specific bag having wall material permeable to water vapor. In accordance with a specific embodiment of the invention, the wall material further includes a deodorizing agent. A lot of deodorizing substances are illustrated, among which zinc ricinoleate and, as another type of deodorizing substances, antimicrobial agents such as benzoic and sorbic acid. However, WO 99/00090 does not describe a preservative and an organic zinc salt in combination to achieve a reduction in odor. In particular, the function of zinc ricinoleate as an ammonia scavenger has not been described.

WO 99/30753 describes deodorizing particles for use in absorbent articles. Deodorizing particles include an effective amount of a means of separating the liquid-activated particles. There are two types of separation agents, namely, physical and chemical. Sodium chloride (NaCl) is given as an example of a physical release agent. Citric acid is illustrated as a chemical release agent. Deodorizing particles for absorbent particles include active deodorizing agents, including zinc cations. Any other known active deodorizing agents are considered otherwise suitable for controlling odors. WO 99/30753 does not mention organic zinc salts.

DE 10256569 A1 relates to water-absorbing, crosslinked, acid-group-containing polymers in the form of predominantly open-cell poroplastics, comprising at least one deodorizing agent selected from compounds with an anhydride group, compounds with an acid group, cyclodextrans, bactericidal substances and surfactants substances with an HLB value of less than 12. One example of bactericidal compounds are zinc compounds, such as zinc chloride. However, organic zinc salts are not mentioned in this reference.

It is further known from other technical fields that organic zinc salts of unsaturated hydroxylated fatty acids, such as zinc ricinoleate, are deodorizing active ingredients (see, for example, DE-A-1792074, DE-A-2548344 and DE-A-3808114).

As is clear from the above, the prior art does not reflect useful, in particular, synergistic effects of using an antibacterial agent or alkali metal chloride in combination with an organic zinc salt.

One technical objective of the present invention is to overcome the disadvantages discussed above in connection with the prior art.

An additional technical task is to provide an absorbent product having an effective deodorization system.

An additional technical objective of the present invention is to substantially reduce or eliminate the formation of ammonia in absorbent articles.

Additional objectives will be apparent from the following description of the invention.

SUMMARY OF THE INVENTION

The present invention relates to an absorbent article, such as a diaper, diaper, panty liner, sanitary napkins or incontinence products, including a protective (top) sheet, a back sheet and an absorbent inner layer (core) placed between said protective sheet and said back sheet wherein said absorbent core (i) is an antibacterial agent or, in an amount of at least 0.01 g / g of said absorbent core, at least one alkali metal chloride or alkali chnozemelnogo metal and (ii) an organic zinc salt.

It has been found that antibacterial agents and an organic zinc salt, such as zinc ricinoleate, interact favorably in suppressing unpleasant odors.

The same observation was made with alkali metal or alkaline earth metal chlorides, such as NaCl. Although they are usually not called “antibacterial,” when used in higher concentrations, they control bacterial growth.

Without being bound by theory, it is contemplated that the following mechanism underlies odor reduction of the present invention. It has been found that ammonia, which produces an unpleasant odor in absorbent products, for example, products used for incontinence, is formed as follows:

Bacteria + urea → NH _3.

In the present invention, antibacterial agents, for example, benzoic acid, or alkali metal chloride, have the function of inhibiting bacterial growth, while an organic zinc salt, such as zinc ricinoleate, removes the constantly formed ammonia (NH ₃ ).

It is an object of the present invention to provide an absorbent article where the amount of undesirable bacteria, such as bacteria producing ammonia, does not increase during use.

DETAILED DESCRIPTION OF THE INVENTION

In the description and claims, the use of the term “includes” is also intended to mean the more limited meanings of “essentially consists of” and “consisting of”.

By “absorbent article” is meant articles capable of absorbing body fluids, such as urine, watery stools, female discharge, or menstrual blood. Such absorbent articles include, but are not limited to, diapers, diapers, napkins, sanitary napkins or incontinence products (such as those used, for example, for adults).

Such absorbent articles have a liquid-permeable protective (top) sheet that, when applied, adheres to the wearer's body. They also include a (preferably liquid impermeable) back sheet, for example, a plastic film, a plastic coated non-woven material or a hydrophobic non-woven material, and an absorbent inner layer located between the liquid-permeable protective sheet and the back sheet.

A suitable protective (top) sheet can be obtained from a wide range of materials, such as woven and non-woven materials (e.g., nonwoven fiber canvas), polymeric materials, such as plastic films with holes, for example, thermoplastic molded films with holes and hydroformed thermoplastic films ; poroplasts; mesh foams; mesh thermoplastic films; and thermoplastic canvases. Suitable woven and non-woven materials may be composed of natural fibers (e.g., wool or cotton fibers), synthetic fibers (e.g., polymer fibers, such as polyester, polypropylene or polyethylene fibers), or a combination of natural and synthetic fibers. When the protective sheet includes a non-woven fabric, it can be obtained using a large number of known methods. For example, the web may be a spunbond production method, combed, wet formed, melt-blown, hydro-entangled, and combinations of the above or the like. In accordance with the invention, it is preferable to use plastic films with holes (for example, thermoplastic films) or non-woven materials based on synthetic fibers, for example, obtained from homo- or copolymers of polyethylene or polypropylene and polymer compositions based on them.

Optionally, at least one additional layer exists between the absorbent core and the backing (top) sheet and can be obtained from hydrophobic or hydrophilic roll or foam materials. By “web material” is meant bonded flat structures based on fibers of paper tissue, woven or non-woven type. The nonwoven material may have the same characteristics as described above for the protective sheets.

In particular, at least one additional layer, for example, in the form of at least one receiving / distributing layer, can participate in fluid retention. Such structures are indicated, for example, in US 5558655, EP 0640330 A1, EP 0631768 A1 or WO 95/01147.

"Foamy materials" are also well known in the art and, for example, are described in EP 0878481 A1 or EP 1217978 A1 on behalf of the present applicant.

The absorbent inner layer may be partially or completely surrounded by an insulating layer. It includes absorbent material, which is usually compressible, snug, non-irritating to the wearer's skin and capable of absorbing and retaining fluids such as urine and other body exudates.

Examples of absorbent materials include a wide variety of liquid absorbent materials commonly used in disposable diapers and other absorbent products, such as chopped wood fiber, commonly referred to as felt or fluff, and creped cellulose wool; melt-blown polymers, including co-molding; chemically hardened, modified or cross-linked cellulose fibers; tissue paper, including fabric layers and fabric laminates, absorbent foams, absorbent sponges, superabsorbent polymers (such as superabsorbent fibers or particles), absorbent gelling materials, or any other known absorbent materials or combinations of materials.

Fibers typically present in the absorbent core are preferably also capable of absorbing body fluids, as is the case for hydrophilic fibers. Most preferably, the fibers are cellulose fibers, such as fluffy wood fiber, cotton, cotton tow, viscose fiber, cellulose acetate and the like, the use of fluff pulp is preferred. Fluff pulp may be mechanical or chemical type, chemical mass is preferred.

The absorbent core layer preferably includes superabsorbent polymers and / or fluff pulp fibers. When used in a mixture, the weight ratio of SAP / fluff pulp is preferably 20 / 80-70 / 30, for example 30 / 70-60 / 40.

The term “superabsorbent polymers” is well known in the art and refers to water-swellable, water-insoluble materials capable of absorbing body fluids many times larger than their own mass. Preferably, the superabsorbent polymer (SAP) is capable of absorbing at least 10 times its mass, preferably at least about 15 times its mass, in particular at least about 20 times its mass in an aqueous solution containing 0.9 wt. .% sodium chloride (under normal measurement conditions, where the superabsorbent surface has free access to the absorbed liquid). To determine the absorption capacity of a superabsorbent polymer, the standard EDANA WSP 241.2 test can be used.

The superabsorbent polymer may be in any form suitable for use in absorbent articles, including particles, fibers, flakes, spheres and the like, a particle shape is preferred.

According to one embodiment of the invention, the superabsorbent polymer in the absorbent core includes an acidic superabsorbent, since acidic components can have a beneficial effect on deodorization. In an alternative embodiment, the absorbent core in the absorbent article does not contain an acidic superabsorbent material, in particular an acidic superabsorbent material having a pH of ≤5.5. In this case, the pH of both the standard (i.e. non-acidic) and acidic SAP is measured using the standard test EANA WSP 200.2.

SAPs are based on homo- and copolymers comprising at least one polymerizable unit having an acid group (for example, a carboxylic acid group or a sulfonic acid group) such as methacrylic acid, acrylic acid, maleic acid, vinyl sulfonic acid. Suitable polymers include, but are not limited to, poly (meth) acrylic acids, ethylene maleic anhydride copolymers, vinyl sulfonic acid polymers and copolymers, polyacrylates, acrylic acid grafted starch, and isobutylene maleic anhydride copolymers. Such polymers are preferably crosslinked, which makes the materials substantially water insoluble. In accordance with one preferred embodiment of the present invention, the superabsorbent material is a crosslinked homo- or copolymer comprising units of (meth) acrylic acid, for example, of the type described in EP 0391108 A2. Standard SAPs have a pH level that ranges from 5.8 or more.

An “antibacterial agent” is defined in the present invention as a compound that is capable of either killing bacteria, such as ammonia producing bacteria that exist in the human urogenital region, or inhibiting the growth of said bacteria.

Preferred antibacterial agents are able to act, starting with a concentration of about 10 ³ CFU / ml liquid for each type of bacteria (CFU is a colony forming unit) and at a given concentration of the antibacterial agent (for example, 10 ^-3 g / g dry absorbent core) bacteria after 12 hours 10 ⁵ CFU / ml liquid for each type of bacteria or lower, preferably 10 ⁴ -10 and more preferably 10 ³ -10 ² . This can be measured in accordance with the method of “measuring the inhibition of bacteria in absorbent bodies” as described in WO 00/35505 (page 17, method 3) on behalf of the present applicant. The absorbent inner layer used in the above method is preferably round, has a diameter of 5 cm, the amount of absorbent material present in the inner layer is 1.16 g and the absorbent inner layer is compressed to a batch of about 8-10 cm ³ / g, and 16 ml of test liquid is added to this. This method evaluates the ability to inhibit growth or kill at least one bacterial strain selected from the species Escherichia coli, Proteus mirabilis and Enterococcus faecalis.

Antibacterial agents for use in the present invention are preferably compounds that are gentle on the skin. It must be remembered that the area of skin in contact with absorbent products, such as diapers, diapers, sanitary napkins or incontinence devices, is sensitive and delicate. Therefore, it is preferable to use antibacterial agents that are approved for use in food (for example, as preservatives) (for example, food preservatives approved at the priority of this application in any member of the EU or the USA or Japan).

The antibacterial agent may be organic or inorganic. It can, for example, be selected from the following organic compounds: isothiazolinones and benzisothiazolinones, oxazolidines, pyridines, optionally chlorinated phenols, bromine compounds, aldehyde and dialdehyde compounds, benzyl alcohols, cresols, p-hydroxybenzoic acids and their esters and salts (paraben compounds ), organic acids and their salts, in particular alkali metal and alkaline earth metal salts, and organic polyacids and their salts, in particular, alkali metal and alkaline earth metal salts. An antibacterial agent belongs to the above classes if it has (includes) the corresponding structural characteristics. Accordingly (further) substituted members such as hydroxylated organic acids are also encompassed by the above classes.

The inorganic antibacterial agent may be selected from sulfites, bisulfites, nitrates, nitrites and iodates of alkali metals such as sodium and potassium, or alkaline earth metals such as calcium and magnesium.

Preferably, one of the following compounds or a mixture thereof is used as an antibacterial agent.

1,2-benzisothiazolin-3-one (BIT, Proxel);

Benzoic acid, E210;

Benzyl alcohol;

2-benzyl-4-chlorophenol (Chlorophene);

1,3-bis (hydroxymethyl) -5,5-dimethylimidazoline-2,4;

5-bromo-5-nitro-1,3-dioxane (Bronidox ^TM);

2-bromo-2-nitropropane-1,3-diol (BNPD);

Succinic acid dialdehyde;

Dehydroacetic acid (6-methylacetopiranone);

Diazolidinyl urea (Germall II ^TM );

1,2-dibromo-2,4-dicyanobutane;

6,6-dibromo-4,4-dichloro-2,2'-methylenediphenol;

Dioxydibenzamidine 3,3'-dibromo-4,4'-heskamethylene (dibromhexamidine);

2,4-dichlorobenzyl alcohol;

5.5'-dichloro-2,2'-dihydroxydiphenylmethane (Dichlorophen);

4,4-dimethyl-1,3-oxacholidine;

Phenols, for example, o-phenylphenol;

Cresols, for example, o-, m- or p-cresol, 4-isopropyl-m-cresol, p-chloro-m-cresol;

2-phenoxyethanol (ethylene glycol monophenyl ether);

1-phenoxypropan-2-ol;

O-phenylphenol and its salts;

Silver phenylmercury salts, including borates;

Formaldehyde;

Fumaric acid, E 297;

Glutaraldehyde;

Glyoxal;

Hexetidine;

Hexamethylenetetramine, E239;

P-hydroxybenzoic acid (4-hydroxybenzoic acid);

P-hydroxybenzoic acid benzyl ester (benzyl paraben);

P-hydroxybenzoic acid N-butyl ester (butyl paraben);

P-hydroxybenzoic acid ethyl ester, E 214 (ethyl paraben);

P-hydroxybenzoic acid ethyl ester sodium salt, E215 (ethyl paraben sodium salt);

P-hydroxybenzoic acid N-heptyl ester (heptyl paraben);

P-hydroxybenzoic acid methyl ester, E 218 (methyl paraben);

P-hydroxybenzoic acid methyl ester sodium salt, E 219 (methyl paraben sodium salt);

P-hydroxybenzoic acid N-propyl ester, E 216 (propyl paraben);

P-hydroxybenzoic acid n-propyl ester sodium salt, E 217 (propyl paraben sodium salt);

1-hydroxy-4-methyl-6 (2,4,4-trimethylpentyl) -2-pyridone;

Imidazolidinyl urea;

Calcium Acetate, E 263;

Calcium Bisulfite, E 227;

Calcium Propionate, E282;

Calcium sulfite, E226;

Potassium disulfite, E 224 (potassium pyrosulfite);

Potassium nitrate, E252;

Potassium propionate, E283;

Potassium Sorbate, E202;

2-chloroacetamide;

N- (3-chloralllyl) hexaminium chloride (Quaternium 15);

1- (4-chlorophenoxy) -1- (imidazol-1-yl) -3,3-dimethylbutan-2-one;

Chlorhexidine;

P-chloro-m-xylene;

5-chloro-2-methyl-4-isothiazolin-3-one;

4-chloro-3,5-xylenol;

Methenamine-3-chloroallyl chloride;

H, n'-methylenebis (5-methyloxazolidine) (Grotan OD ^TM );

2,2'-methylene-bis- (3,4,6-trichlorophenol) (Hexachlorophene);

Lactic acid E270;

Myristylic acid;

Natamycin, E235 (Pimaricin);

Sodium Acetate, E262;

Sodium benzoate, E211;

Sodium diacetate, E262;

Sodium formate, E237;

Sodium Nitrate, E251;

Sodium nitrite, E 250;

Sodium Propionate, E281;

2-pyridinethiol-1-sodium oxide (Omadin ^TM and PyrionNa ^TM );

Sodium Sorbate, E201;

Sodium sulfite, E221;

Sodium disulfite, E223 (sodium pyrosulfite);

Sodium iodate;

Sodium hydrosulfite, E222 (sodium bisulfite);

Nisin, E234;

2-n-octyl-4-isothiazolin-3-one (Kathon893 ^TM and SkaneM-8 ^TM );

Paraformaldehyde;

Poly (1-hexamethylene biguanide hydrochloride);

Propionic acid, E280;

Salicylic acid (2-hydroxybenzoic acid);

Sorbic acid, E200;

Inorganic sulfites;

Sulfur dioxide (aq.), E220;

2,2'-thio-bis- (4,6-dichlorophenol) (Bithionol);

Thimerosal (ethyl mercury thiosalicylate);

1,3,5-triazine-1,3,5- (2H, 4H, 6H) -triethanol;

Trichlocarban (3,4,4'-trichlorocarbonylanide);

2,4,4'-trichloro-2'-hydroxydiphenyl ether (Irgasan DP 300 ^TM and Triclosan ^TM );

3,4,4-trimethyl-1,3-oxazolidine (Bioban CS 1135 ^TM and Oxaben A ^TM );

Undecenoic acid;

Inorganic hydrosulfites;

Zinc bis- (2-pyridinethiol-1-oxide) (Zink-Omadin ^TM );

Malic acid, E296 (hydroxy succinic acid);

Acetic acid, E260;

Derivatives of morpholine, for example 4- (nitrobutyl) morpholine and 4,4 '- (2-ethyl-2-nitrotrimethylene) dimorpholine (Bioban P 1487 ^TM or Bioban CS 1248 ^TM );

Oxazolidines;

Pyridine derivatives;

Kathon CG (mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one); and

1,1,1-trichloro-2-methyl-2-propanol (chlorobutanol).

The antibacterial agent is preferably selected from organic acids and polyacids (e.g., diacids or tricacids) and their salts. The organic (poly) acid may be substituted with one, two or more hydroxy groups. The organic (poly) acid may be unsaturated (e.g., mono- or di-unsaturated) or saturated, linear or branched aliphatic carboxylic acid, preferably having from 2 to 18 carbon atoms, more preferably from 3 to 8 carbon atoms. Their examples are already mentioned in the above list. The organic acid may also be aromatic (poly) acid, preferably phenyl (poly) carboxylic acid, preferably having from 7 to 18 carbon atoms, in particular from 7 to 10 carbon atoms, as in benzoic acid, p-hydroxybenzoic acid or salicylic acid . The salt is preferably an alkali metal salt (e.g., K or Na) or an alkaline earth metal salt (e.g., Ca or Mg).

Acid antibacterial agents, including the above organic (poly) acids, are preferably weak acids, in particular having a pK value of at least 3, in particular at least 4, for example, from 4 to 5 (for polyacids, pK1 value) measured in water at 25 ° C. Acetic acid has, for example, pK 4.75, sorbic acid pK 4.76 and benzoic acid pK 4.19.

More preferably, in the present invention, benzoic acid, sorbic acid, tartaric acid or citric acid, most preferably benzoic acid, are used as an antibacterial agent.

The alkali metal chloride may be potassium chloride (KCl) or sodium chloride (NaCl), and preferably NaCl. The alkaline earth metal chloride may be magnesium chloride (MgCl ₂ ) or calcium chloride (CaCl ₂ ). According to the invention, an alkali metal chloride or an alkaline earth metal chloride is present in an amount of at least 0.01, preferably at least 0.05, more preferably at least 0.1 g per gram of dry absorbent internal layer.

There are no specific restrictions regarding the organic zinc salt used in combination with component (i). In accordance with the present invention, zinc salts of organic carboxylic acids having from 2 to 30 carbon atoms, in particular from 12 to 24 carbon atoms, are preferably used. The carboxylic acid group may be attached to aliphatic, aliphatic-aromatic, aromatic-aliphatic, alicyclic or aromatic residues, where the aliphatic chain or alicyclic ring (s) may be unsaturated and are optionally substituted, for example, hydroxy or C1-C4 alkyl. Such salts include zinc acetate, zinc lactate, zinc ricinoleate and zinc abietate. More preferably, the zinc salt is a zinc salt of unsaturated hydroxylated fatty acids having from 8 to 18 carbon atoms. Although there are no specific restrictions on the number of unsaturated double bonds or hydroxy groups, fatty acids having one or two unsaturated double bonds and one or two hydroxyl groups are likely to be preferred. The most preferred embodiment is zinc ricinoleate. The organic zinc salt can also be activated by the presence of amino acids, as in TEGO® Sorb, available from Degussa. Further, the organic zinc salt used in the present invention may also be capable of removing malodorous substances chemically based on amines, e.g., nicotine in cigarette smoke, thio compounds, e.g., allicin in garlic and onions, and acids, e.g., isovaleric acid human sweat and butyric acid. For example, zinc ricinoleate, which, for example, is sold by Degussa under the trade name TEGO® Sorb, has the described additional odor eliminating effect, in addition to ammonia removal.

According to a particular preferred embodiment of the invention, the antibacterial agent (as one alternative to component (i)) is selected from the group consisting of benzoic acid, sorbic acid, tartaric acid and citric acid or a mixture thereof, and the organic zinc salt is zinc ricinoleate. According to another preferred embodiment of the invention, sodium chloride is used as component (i) and the organic zinc salt is zinc ricinoleate.

With respect to the amount of component (i) and the organic zinc salt used in the present invention, there are no specific limitations. In the present description, these amounts are expressed in terms of the mass (in g) of the dry absorbent core. As used herein, the term “dry” as used in connection with an absorbent core is understood to not add water to the absorbent core and that water present in the absorbent core is only the inevitable residual water from production. For the purposes of the present invention, the absorbent inner layer is preferably regarded as “dry” when after the round test inner layer having a thickness of 5-6 mm, a diameter of 5 cm and pressed to a batch of about 8-10 cm ³ / g is held for at least at least one week at ambient temperature (for example, 20 ° C) and the established relative humidity, for example, 50% of OB.

While there are no specific restrictions on the amount of the antibacterial agent used in the present invention, while the object of the present invention is achieved, the amount of the antibacterial agent is preferably at least 1 × 10 ^-4 g, more preferably at least 5 × 10 ^{- 4} g, most preferably at least 1 × 10 ⁻³ g per g of dry absorbent core. However, there are cases where the antibacterial agent can be used in an amount as low as 5-10 ppm of the antibacterial agent (a) (by weight) with respect to the dry absorbent core. This is Kathon® CG, which is a mixture of two compounds, namely 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one. Adding an additional antibacterial agent over a certain amount of the antibacterial agent (for example, 0.01 g or 0.1 g per g dry absorbent core) may no longer be economical.

The amount of alkali metal chloride or alkaline earth metal chloride, such as sodium chloride, is at least 0.01 g, preferably at least 0.05 g, for example at least 0.1 g per g of dry absorbent inner layer. There is no specific upper limit for the content of alkali metal (alkaline earth) chloride, although an increase over values such as 0.5 g per g of absorbent inner layer or 1 g per g of absorbent inner layer may no longer be useful.

Very low amounts of organic zinc salts already interact with component (i) with a very effective odor control. A preferred lower weight limit of an organic zinc salt (calculated as zinc), such as zinc ricinoleate, is likely to be at least 1 x 10 ^-5 g per g dry absorbent core. More preferred values are at least 1 x 10 ^-4 g, even more preferably at least 5 x 10 ^-4 g per g of dry absorbent core, even more preferably at least 1 x 10 ^-3 g per g of dry absorbent core. There is no specific upper limit, at least for economic reasons, since a point can be reached where an additional increase in the zinc content, for example, to 0.1 or 1 g of zinc per g of absorbent inner layer will no longer be useful if this is not accompanied by enhanced odor suppression.

The mass ratio of the antibacterial agent, alkali metal chloride or alkaline earth metal chloride, and organic zinc salt is also not specifically limited, but is preferably 15 / 1-1 / 5, more preferably 5 / 1-1 / 2, for example, 3 / 1-1 /one.

The present invention also does not have any limitations regarding the method of incorporating an antibacterial agent or alkali metal chloride or alkaline earth metal (hereinafter also referred to as "chloride") and an organic zinc salt into the absorbent inner layer. However, immersion, impregnation and spraying are preferred.

For example, it is possible to process cellulose fibers for use in an absorbent core, preferably fluff pulp, with a mixed solution of organic zinc salt before or during mixing with SAP. Alternatively, the fibers for use in the absorbent core can be sequentially treated with separate solutions, for example, by immersion and spraying, the first solution includes an antibacterial agent or chloride, and the second solution includes an organic zinc salt.

According to one embodiment of the invention, a super absorbent (SAP) for use in an absorbent core is treated with a mixed solution of an organic zinc salt before or during mixing with cellulose fibers, in particular fluff pulp. Alternatively, SAP for use in an absorbent core can be sequentially treated with separate solutions, for example, by immersion and spraying, the first solution includes an antibacterial agent or chloride, and the second solution includes an organic zinc salt.

According to another embodiment of the invention, a mixed solution of an organic zinc salt and an antibacterial agent or chloride is sprayed onto fibers, most preferably onto sheets of fluff pulp obtained from the manufacturer. The mixed solution can be sprayed onto the sheets of fluff pulp directly by the manufacturer of these sheets before the sheets are delivered to the manufacturer of absorbent articles. This is a particularly preferred embodiment of the invention, as it avoids the additional step of spraying the mixed solution or separate solutions (i.e., the organic zinc salt and component (i)) in the manufacture of the absorbent article. Alternatively, sheets of cellulose are immersed in a solution. SAP can be added during or after sheet formation to produce an absorbent core treated in accordance with the present invention.

The most preferred way is to pretreat SAP or cellulose fibers, in particular fluff pulp fibers, with a mixed solution or separate solutions of an organic zinc salt and an antibacterial agent or chloride to incorporate such components together with cellulose into the absorbent core during the formation of the core.

According to one preferred method of use, the solution (s) of component (i), in particular benzoic acid, and component (ii), in particular zinc ricinoleate, are sprayed on one or both sides of the absorbent core, or on one or both sides of the individual its constituent layers.

The solvent used for the mixed solution of (i) an antibacterial agent or chloride and (ii) an organic zinc salt may be water, preferably a volatile organic solvent, such as ethanol, or a mixture of water and a water-miscible organic solvent, such as ethanol, until then while components (i) and (ii) are dissolved in it or can be dispersed in it. Preferably, the same solvents are also used in the preparation of two separate solutions of components (i) and (ii). In the case of two solutions, solvents can be selected independently depending on the solubility of component (i) and the organic zinc salt. Preferably, components (i) and (ii) are present in the solution (s) in a relatively high concentration, preferably 1-30 wt.%. The use of such concentrated solutions ensures that the ability of the absorbent material to absorb does not deteriorate more than necessary. Commercially available solutions of organic zinc salts can also be used, such as TEGO® Sorb A30, available from Degussa (active substance content 30 wt.%, Amino acid activated zinc ricinoleate), optionally in diluted form, to which an appropriate amount of the desired compound is added ( i).

The back sheet prevents contamination of exudates absorbed by the absorbent layer and contained in the product, other external products that may come into contact with the absorbent product, such as sheets and underwear. In preferred embodiments, the backsheet is substantially impervious to liquids (e.g. urine) and includes a laminate of a nonwoven product and a thin plastic film such as a thermoplastic film having a thickness of from about 0.012 mm to about 0.051 mm. Suitable backsheet films include those manufactured by Tredegar Industries Inc. Terre Haute, Ind. and sold under the trade names X15306, X10962 and X10964. Other suitable backsheet materials may include breathable materials that allow water vapor to escape from the absorbent article while preventing passage of exudates through the backsheet. Examples of breathable materials may include materials such as woven webs, non-woven webs, composite materials such as film-coated non-woven webs, and microporous films.

The above elements of the absorbent article may be combined, optionally with other typical elements of the absorbent article, in a manner known in the art.

The present invention also relates to cellulosic fibers, in particular cellulosic fibers of fluff pulp, including components (i) and (ii) as described above. Cellulose fibers can be obtained by treating them as described above.

The following examples and comparative examples illustrate the present invention without limiting it.

EXAMPLE 1

Round absorbent inner test layers having a mass of about 1.48 g and a diameter of 5 cm were stamped from the absorbent inner layer obtained in the experimental setup. The standard method for producing the inner layer slab was used to produce the inner layer in the experimental setup. The absorbent inner layer consisted of a homogeneous mixture of fluff pulp, sodium chloride and superabsorbent material. The fluff pulp used was 0.69 g of Weyerhauser cellulose (NB 416) and the superabsorbent material was 0.47 g of super absorbent (Dow Chemicals XZ 91030.03). Sodium chloride (NaCl) was used in an amount of 163 g / m ² (corresponding to 0.32 g / g of the dry absorbent core). The absorbent core was pressed to a batch of about 8-10 cm ³ / g.

To the absorbent core was added 1.3 ml of a solution containing 0.5 wt.% Zinc ricinoleate (available from Degussa under the trade name TEGO® Sorb A30 and diluted accordingly) or by applying the solution to the surface (on one side) or immersing on one side the inner layer into the solution. 1 week after treatment, the absorbent core was allowed to absorb 16 ml of synthetic urine in accordance with Method A as described below, and then left at room temperature.

6 hours and 8 hours after the absorption of synthetic urine, the amount of ammonia formed was measured.

Five measurements were averaged to mean. The results are shown in Table 1.

Method A: Measurement of ammonia inhibition in the absorbent core

Absorbent inner layers were prepared as described above. Received test fluid 1. A suspension of bacteria Proteus mirabilis was cultured in a nutrient medium at 30 ° C overnight. The transplanted cultures were bred and the number of bacteria was determined. The final culture contained approximately 10 ⁵ bacteria per ml of test liquid. The absorbent inner layer was placed in a plastic container and Test liquid 1 was added to the absorbent inner layer, after which the container was incubated at 35 ° C for 6 and 8 hours, respectively, after which samples were obtained from the containers using a hand pump and the so-called Drager tube. The ammonia content was obtained as a color change on a scale graduated in ppm or volume percent.

Test fluid 1.

Sterile synthetic urine to which microorganism growth medium was added. Synthetic urine containing mono- and divalent cations and anions and urea was obtained in accordance with the information in Geigy, Scientific Tables, Vol.2, 8th ed. 1981 p. 53. The microbial growth medium is based on Hook and FSA information for enterobacteria. The pH of this mixture was 6.6.

COMPARATIVE EXAMPLE 1

An absorbent core was prepared in the same manner as in Example 1, except that no solution was exposed to the absorbent core so that it did not contain zinc ricinoleate at all.

COMPARATIVE EXAMPLE 2

An absorbent inner layer was obtained in the same manner as in Example 1, with the only difference that the inner layer did not contain sodium chloride (the mass of the absorbent inner layer was about 1.16 g) and that the solution used to treat the absorbent inner layer contained 6 wt. % zinc ricinoleate and did not contain sodium chloride.

The results with respect to the formation of ammonia of Example 1 and Comparative examples 1 and 2 are shown in the following Table 1.

Table 1 Sample Description Ammonia production (ppm) 6 h Ammonia production (ppm) 8 h SP 1 NaCl 77 520 SP 2 Zn ¹ <19 270 N 1 NaCl + Zn ¹ 10 140 ¹ zinc ricinoleate

The above experiments showed that the combined use of an alkali metal chloride, such as sodium chloride, and an organic zinc salt, such as zinc ricinoleate, suppresses the formation of ammonia to a very unexpected degree.

Claims (11)

1. An absorbent article, such as a diaper, diaper, sanitary napkin or incontinence product, comprising a protective sheet, a back sheet and an absorbent inner layer, sandwiched between said protective sheet and said back sheet, where said absorbent inner layer includes
(i) in an amount of at least 0.01 g per g of dry absorbent core, at least one alkali metal or alkaline earth metal chloride, and
(ii) an organic zinc salt. 2. The absorbent product according to claim 1, where the absorbent inner layer includes a mixture of fibers, in particular fluff pulp, and superabsorbent material. 3. The absorbent product according to claim 1 or 2, where the amount of organic zinc salt is so much that the absorbent inner layer contains at least 5 · 10 ^-4 g Zn per g of dry absorbent inner layer. 4. The absorbent product according to claims 1 or 2, where the mass ratio of component (i) and organic zinc salt (ii) in terms of zinc is 15 / 1-1 / 5. 5. The absorbent product according to claims 1 or 2, obtained by treating the absorbent inner layer with a mixed solution of component (i) and an organic zinc salt (ii). 6. The absorbent product according to claim 1, where the alkali metal chloride is sodium chloride. 7. An absorbent product according to claims 1 or 2, wherein the organic zinc salt is selected from zinc salts of carboxylic acids having from 2 to 30 carbon atoms. 8. The absorbent product according to claim 7, where the carboxylic acid is an unsaturated hydroxylated fatty acid having from 8 to 18 carbon atoms. 9. The absorbent product of claim 8, where the zinc salt is zinc ricinoleate. 10. The absorbent product according to claims 1 or 2, where the back sheet is impervious to liquid. 11. The absorbent product according to claims 1 or 2, where component (i) is sodium chloride and component (ii) is zinc ricinoleate.