JPH0852203A - Absorbent article - Google Patents

Abstract

PURPOSE:To provide an absorbent article which is capable of suppressing the lowering in body fluid holdability of an absorber contg. a highly water absorbent polymer with lapse of time and has excellent absorbing characteristic. CONSTITUTION:This absorbent article has a liquid permeable top sheet, a liquid impermeable back sheet and the absorber contg. the highly water absorbent polymer arranged between these two sheets. The absorber contains a chelate agent compd. which has a part capable of forming Cu ions and chelate and has the solubility of the Cu salt in a physiological salt soln. of 25 deg.C of <=0.01wt.%. The content ratio of this chelate agent compd. is specified to 0.0001 to 30 pts.wt. per 100 pts.wt. highly water absorbent polymer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to absorbent articles such as disposable diapers for infants, adults or incontinence, or sanitary napkins for women.

[0002]

2. Description of the Related Art Absorbents for absorbent articles such as disposable diapers for infants, adults or incontinent persons, or feminine sanitary napkins have recently been made of cotton, pulp, A composite material of a fibrous material such as paper and a super absorbent polymer is used. Also,
Recently, from the viewpoints of portability and wearability, it has been required to make these absorbent articles compact, and as a result, many absorbent articles that have been made compact by increasing the content ratio of the superabsorbent polymer are put on the market. Has been done.

However, in the conventional absorbent articles using the absorbent containing these superabsorbent polymers, particularly in the absorbent articles having a high content ratio of the superabsorbent polymers,
After absorbing body fluid such as urine, menstrual blood, sweat, etc., the swollen gel of superabsorbent polymer which has absorbed body fluid changes with time due to the action of radical-generating species such as L-ascorbic acid (salt) contained in the body fluid. It deteriorates and decomposes, and as a result, the body fluid retention of the absorber decreases over time, causing liquid leakage, which results in soiling of the futon, sheets, clothes, etc. with body fluid, or when the weight of the absorber is applied. There was a case where the amount of liquid returned increased and the comfort during wearing was impaired.

Further, the decomposition reaction of the superabsorbent polymer by the radical-generating species is carried out in an aqueous solution in which a transition metal ion such as iron or copper capable of taking two or more kinds of oxidation numbers coexists in a water-containing state, especially in an air atmosphere. It is remarkable under the water-containing condition.

As described above, in the conventional absorbent article using the superabsorbent polymer as the absorbent body, the retention of the body fluid of the absorbent body is deteriorated with time, so that the liquid returns more and the liquid leaks easily. There is a demand for an absorbent article which has problems, does not have a decrease in the body fluid retention of an absorbent body containing a superabsorbent polymer over time, and has excellent body fluid absorption characteristics.

[0006] Therefore, various substances are used for suppressing the deterioration and decomposition of the swollen gel formed by the superabsorbent polymer in the absorbent body absorbing the body fluid with time, and for stabilizing the body fluid retention of the absorbent body with time. JP-A-63-272349, JP-B-5-34383, JP-A-2-255804, and JP-A-3-179008 have been proposed as a stabilizer for the swollen gel. Sulfur-containing reducing agent,
Although methods using oxygen-containing reducing inorganic salts, water-soluble chain transfer agents, etc. have been reported, sufficient effects have not been obtained even with these methods, and any of the above stabilizers produces a foul odor. However, since it is a substance that induces skin irritation / allergy, there is a problem in safety and the like when it is used in an absorbent article which may come into contact with the human body.

[0007] Therefore, an object of the present invention is to provide an absorbent article which is excellent in absorption characteristics, in which a decrease in the body fluid retention of the absorbent body containing the superabsorbent polymer with time is suppressed.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a specific chelating agent compound is contained in an absorber having a super absorbent polymer. It has been found that the article can achieve the above object.

The present invention has been made based on the above findings, and contains a liquid-permeable top sheet, a liquid-impermeable back sheet, and a super absorbent polymer disposed between these sheets. In an absorbent article including an absorber, the absorber has a site capable of forming a chelate with Cu ions, and the solubility of the Cu salt in physiological saline at 25 ° C is 0.01% by weight or less. And the content ratio of the chelating agent compound is 0.0001 to 30 with respect to 100 parts by weight of the super absorbent polymer.
It is intended to provide an absorbent article which is part by weight.

The absorbent article of the present invention will be described in more detail below. The absorbent article of the present invention comprises a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body containing a super absorbent polymer disposed between these sheets, and the super absorbent The absorber containing the polymer is C
25 ° C., having a site capable of forming a chelate with u ion
Contains a chelating agent compound in which the solubility of the Cu salt in the physiological saline is 0.01 wt% or less, and the content ratio of the chelating agent compound is 100% by weight.
It is characterized by being 0.0001 to 30 parts by weight with respect to parts by weight.

The absorbent body is mainly composed of hydrophilic fibers, and examples of the hydrophilic fibers include defibrated pulp, cellulosic fibers, or fibers obtained by hydrophilizing thermoplastic fibers. Preferred examples include those used for the absorbent body of general absorbent articles without particular limitation.

In the present invention, the superabsorbent polymer contained in the absorber is not particularly limited as long as it is one that is usually used in absorbent articles. For example, a polymer compound having a carboxyl group or a salt thereof can be used. Partially crosslinked products or partially crosslinked polysaccharides are particularly preferably used. Examples of the partially crosslinked polymer compound having a carboxyl group or a salt thereof include polyacrylic acid salt crosslinked products, poly (vinyl alcohol / acrylic acid salt) copolymer crosslinked products, and starch-acrylic acid salt graft copolymers. Examples thereof include a polymer (crosslinked product) and a polyvinyl alcohol-polymaleic anhydride graft copolymer crosslinked product. Examples of partially crosslinked polysaccharides include crosslinked carboxymethyl cellulose salts. In addition, "Poise SA-
Commercially available products such as "20" brand name, manufactured by Kao Corporation, "Diawet" brand name, manufactured by Mitsubishi Petrochemical Co., Ltd.
In addition, these super absorbent polymers may be used alone or in combination of two or more kinds.

The blending ratio of the hydrophilic fiber and the superabsorbent polymer (content ratio of the superabsorbent polymer) in the absorbent body used in the present invention is preferably 1 to 99 parts by weight of the hydrophilic fiber. On the other hand, the superabsorbent polymer is 99 to 1 part by weight, more preferably hydrophilic fiber 80 to 40.
20 to 60 parts by weight of the high-absorbent polymer with respect to parts by weight.

The structure of the absorber is not particularly limited,
As the structure, for example, a structure in which the superabsorbent polymer is sandwiched between absorbent paper or a nonwoven fabric made of the hydrophilic fiber, or after mixing the superabsorbent polymer and defibrated pulp, into a sheet shape. Examples include the formed structure and the like.

The chelating agent compound used in the present invention has a site capable of forming a chelate with Cu ions, and has a solubility of Cu salt of 0.
It is not more than 01% by weight. Here, the “site capable of forming a chelate with Cu ion” is a compound capable of forming a coordination bond with a metal ion in a compound generally considered to act as a ligand in the field of complex chemistry. Means the position. Further, the “solubility” in the present invention means 25 ° C.
In above, the Cu salt of the chelating agent compound was added to physiological saline and dissolved for 30 minutes with stirring, and then the maximum addition amount (weight) of the Cu salt of the chelating agent compound was adjusted so that the solution became transparent. It means the concentration (% by weight) divided by weight.

The above-mentioned chelating agent compound is contained in the swelling gel formed by absorbing the body fluid of the superabsorbent polymer in the body fluid as compared with the additive which has been conventionally used as a stabilizer for the superabsorbent polymer. The ability to suppress decomposition / deterioration by radical-generating species such as L-ascorbic acid is remarkably high. The content ratio of the chelating agent compound in the absorber is 0.0001 to 30 with respect to 100 parts by weight of the superabsorbent polymer.
The amount is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight. The above content ratio is
When the amount is less than 0.0001 parts by weight, the effect of the chelating agent compound does not appear, and even when it is used in an amount of more than 30 parts by weight, the effect is not improved and the physical properties of the absorber tend to be impaired. It is preferable to set the inside.

The above chelating agent compound is a Cu ion (C
It is particularly preferable that the common logarithmic value (pKCu) of the chelate stability constant at 25 ° C. with (u ²⁺ ion or Cu ⁺ ion) is 3 or more. When pKCu is less than 3, the effect such as decrease in body fluid retention over time in an absorbent article including an absorbent body containing a superabsorbent polymer may not be exhibited, so it is preferably set to the above value or more.

The chelating agent compound used in the present invention is preferably selected from the following three groups. (1) First group: at least 1 selected from the group consisting of a hydrophobic component composed of a saturated or unsaturated hydrocarbon group having 6 to 30 carbon atoms, and a carboxylic acid group, a sulfonic acid group, a hydroxyl group and a phosphoric acid group. A compound consisting of a hydrophilic part having two groups. (2) Second group: β-diketone derivatives. (3) Third group: tropolone derivatives. In the present invention, one kind or two or more kinds of compounds selected from any one group out of the above three groups can be used, and each of at least two groups out of the above three groups can be used. One or two or more selected compounds may be used in combination. Further, the chelating agent compound selected from these three groups has a pKCu of about 3 or less.
The above is also preferable.

The chelating agent compound belonging to the above-mentioned first group comprises a hydrophobic part consisting of a saturated or unsaturated hydrocarbon group having 6 to 30 (preferably 12 to 22) carbon atoms, a carboxylic acid group, a sulfonic acid group, And a hydrophilic part having at least one group selected from the group consisting of a hydroxyl group and a phosphate group. Examples of the saturated hydrocarbon group include a linear or branched alkyl group and a cycloalkyl group, and examples of the unsaturated hydrocarbon group include a linear or branched alkenyl group and a phenyl group. Examples of the chelating agent compound having such a group include polyvalent carboxylic acid derivatives, hydroxycarboxylic acid derivatives, iminodiacetic acid derivatives, organic acid amide derivatives, N-acylated amino acid derivatives, phosphoric acid ester derivatives, phosphonic acid derivatives and Examples thereof include polyvalent phosphonic acid derivatives and their alkali metal salts and alkaline earth metal salts, but are not limited to these examples.

Examples of the polycarboxylic acid derivative include alkylmalonic acid, alkenylmalonic acid and salts thereof. Examples of the hydroxycarboxylic acid derivative include citric acid monoalkyl ester, citric acid monoalkenyl ester, and salts thereof. Examples of iminodiacetic acid derivatives include N-alkyl-
Examples thereof include N′-carboxymethylaspartic acid, N-alkenyl-N′-carboxymethylaspartic acid and salts thereof. Examples of the organic acid amide derivative include citric acid monoalkylamide, citric acid monoalkenylamide, and salts thereof. Examples of the N-acylated amino acid derivative include N-acylated glutamic acid, N-acylated aspartic acid and salts thereof. Examples of the phosphoric acid ester derivative include monoalkyl phosphoric acid ester, monoalkenyl phosphoric acid ester, and salts thereof. Examples of the phosphonic acid derivative include alkylphosphonic acid, alkenylphosphonic acid and salts thereof, phenylphosphonic acid and salts thereof, and the like. Examples of the polyvalent phosphonic acid derivative may include alkylenebis (nitrilogymethylene) tetraphosphonic acid and salts thereof.

Among these, citric acid monoalkylamide and citric acid monoalkenylamide and salts thereof, citric acid monoalkyl ester and citric acid monoalkenyl ester and salts thereof, alkylmalonic acid and alkenylmalonic acid, and them Salt of N-alkyl-N'-carboxymethylaspartic acid and N-
Alkenyl-N'-carboxymethylaspartic acid and salts thereof, N-acylated glutamic acid and salts thereof, monoalkyl phosphate ester and monoalkenyl phosphate ester and salts thereof are preferably used as the chelating agent compound, and particularly, Citric acid derivatives such as citric acid monoalkylamide and citric acid monoalkenylamide and salts thereof, citric acid monoalkyl ester and citric acid monoalkenyl ester, and salts thereof are more effective because they have a high stabilizing effect on the superabsorbent polymer. preferable.

The above citric acid monoalkylamide, citric acid monoalkenylamide and salts thereof are preferably represented by the following general formula (I).

[0023]

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The above citric acid monoalkylamides and citric acid monoalkenylamides and salts thereof can be synthesized by known methods. For example, it can be obtained by hydrolyzing and neutralizing an imine obtained by completely dehydrating and condensing an amine and citric acid. By appropriately selecting the number of carbon atoms of R ¹ in the general formula (I), the intended citric acid monoalkylamide and citric acid monoalkenylamide and salts thereof can be obtained.
^{If the} number of carbon atoms of ¹ is more than 30, the water solubility is remarkably deteriorated, and if the number of carbon atoms of R ¹ is less than 6, the performance as a stabilizer of the super absorbent polymer is deteriorated. The number of carbon atoms of R ¹ is more preferably 12 to 22.

The above citric acid monoalkyl ester, citric acid monoalkenyl ester, and salts thereof are preferably represented by the following general formula (II).

[0026]

Embedded image

The above-mentioned citric acid monoalkyl ester, citric acid monoalkenyl ester and salts thereof can be synthesized by known methods. For example, it can be obtained by dehydration condensation of alcohol and citric acid. General formula (II)
By appropriately selecting the number of carbon atoms of R ^{2 in the above} , it is possible to obtain the intended citric acid monoalkyl ester, citric acid monoalkenyl ester and salts thereof, but when the number of carbon atoms of R ² exceeds 30, When the water-solubility is remarkably deteriorated and the number of carbon atoms of R ² is less than 6, the performance as a stabilizer of the super absorbent polymer is deteriorated. The number of carbon atoms of R ² is more preferably 12 to 22.

The alkylmalonic acid, alkenylmalonic acid and salts thereof are preferably those represented by the following general formula (III)
It is represented by.

[0029]

[Chemical 3]

The above-mentioned alkylmalonic acid, alkenylmalonic acid and salts thereof can be synthesized by a known method. For example, it can be obtained by adding α-olefin to methyl malonate or ethyl malonate to give methyl alkylmalonate or ethyl alkylmalonate, which is then hydrolyzed and neutralized. R in the general formula (III)
Alkylmalonic acid, alkenylmalonic acid, and salts thereof suitable for the purpose can be obtained by appropriately selecting the number of carbon atoms of ³ , but if the number of carbon atoms of R ³ exceeds 30, the water solubility becomes significantly poor. , R ³ has 6 carbon atoms
If it is less than the above range, the performance of the superabsorbent polymer as a stabilizer deteriorates. The number of carbon atoms of R ³ is more preferably 12 to
22.

The above N-alkyl-N'-carboxymethylaspartic acid, N-alkenyl-N'-carboxymethylaspartic acid and salts thereof are preferably represented by the following general formula (IV).

[0032]

[Chemical 4]

The above N-alkyl-N'-carboxymethylaspartic acid, N-alkenyl-N'-carboxymethylaspartic acid and salts thereof can be synthesized by known methods. For example, it is obtained by carboxymethylating an alkylaminosuccinic acid obtained by adding an amine to maleic acid with carboxymethyl chloride and neutralizing it. By appropriately selecting the number of carbon atoms of R ⁴ in the general formula (IV), N-alkyl-N′-carboxymethylaspartic acid and N-
Alkenyl-N'-carboxymethylaspartic acid and salts thereof can be obtained, but when R ⁴ has more than 30 carbon atoms, water solubility is significantly deteriorated, and when R ⁴ has less than 6 carbon atoms. The performance of the superabsorbent polymer as a stabilizer deteriorates. The number of carbon atoms of R ⁴ is more preferably 12 to 22.

The above monoalkyl phosphate ester, monoalkenyl phosphate ester and salts thereof are preferably represented by the following general formula (V).

[0035]

[Chemical 5]

The above-mentioned monoalkyl phosphate ester, monoalkenyl phosphate ester and salts thereof can be synthesized by known methods. For example, it can be obtained by phosphorylating an alcohol with phosphorus pentoxide, phosphorus oxychloride or polyphosphoric acid. By appropriately selecting the number of carbon atoms of R ⁵ in the general formula (V), the desired monoalkyl phosphate ester, monoalkenyl phosphate ester and salts thereof can be obtained.
^{When the} number of carbon atoms of ⁵ exceeds 30, the water solubility is remarkably deteriorated, and when the number of carbon atoms of R ⁵ is less than 6, the performance as a stabilizer of the super absorbent polymer deteriorates. The number of carbon atoms of R ⁵ is more preferably 12 to 22.

The above N-acylated glutamic acid and salts thereof are preferably represented by the following general formula (VI).

[0038]

[Chemical 6]

The above N-acylated glutamic acid and salts thereof can be synthesized by known methods.
It is also available as a commercial product. R ⁶ in the general formula (VI)
By appropriately selecting the number of carbon atoms of —CO—, the desired N-acylated glutamic acid and salts thereof can be obtained. However, when the number of carbon atoms of R ⁶ —CO— exceeds 30, the water solubility becomes poor. If the number of carbon atoms of R ⁶ —CO— is less than 6, the performance of the superabsorbent polymer as a stabilizer deteriorates. The number of carbon atoms of R ⁶ —CO— is more preferably 12 to 22.

The above N-acylated aspartic acid and salts thereof are preferably represented by the following general formula (VII).

[0041]

[Chemical 7]

The above N-acylated aspartic acid and salts thereof can be synthesized by known methods, but are also available as commercial products. By appropriately selecting the number of carbon atoms of R ⁷ —CO— in the general formula (VII), the desired N-acylated aspartic acid and salts thereof can be obtained, but the carbon atom of R ⁷ —CO— Number 3
When it exceeds 0, the water solubility is remarkably deteriorated, and when the number of carbon atoms of R ⁷ —CO— is less than 6, the performance as a stabilizer of the superabsorbent polymer deteriorates. The number of carbon atoms of R ⁷ —CO— is more preferably 12-22.

The chelating agent compound belonging to the first group is more safe than the additives conventionally used as stabilizers for superabsorbent polymers, and has the ability to prevent decomposition / degradation of superabsorbent polymers. It is expensive. The chelating agent compounds belonging to the first group may be used alone or in combination of two or more kinds.

The β-diketone derivative belonging to the above second group is capable of forming a chelate with Cu ions and
It is a compound in which the solubility of the Cu salt in physiological saline at 0 ° C is 0.01% by weight or less. And
The above-mentioned β-diketone derivative is more safe than the additives conventionally used as stabilizers for superabsorbent polymers and has a high ability to prevent decomposition / deterioration of superabsorbent polymers.

Examples of such compounds include acetylacetone, benzoylacetone, dibenzoylmethane, furoylacetone, benzoylfuroylmethane, 4-hydroxy-benzoylacetone, 4-tert-butyl-4'-.
Hydroxy-dibenzoylmethane, 4-hydroxybenzoylmethane-tert-butyl ketone, 4-hydroxy-
Examples thereof include compounds such as 4′-hydroxy-dibenzoylmethane, but are not limited to these examples.
Of these, acetylacetone, 4-hydroxy-benzoylacetone, and 4-hydroxybenzoylmethane-tert-butylketone are preferably used.
These β-diketone derivatives belonging to the above second group are
Each may be used alone, or two or more kinds may be used in combination.

The tropolone derivative belonging to the above third group is capable of forming a chelate with Cu ions and is at 25 ° C.
The solubility of the Cu salt in physiological saline is 0.01 wt% or less. Such a tropolone derivative is a natural product found in some kinds of trees, and even if it is brought into contact with a human body, an animal or the like at a high concentration, it does not have a serious influence and is highly safe. And, it has not been known so far to use the above tropolone derivative for stabilizing (preventing decomposition / deterioration) of the superabsorbent polymer, and in particular, a superabsorbent polymer composition comprising the above tropolone derivative. It has not hitherto been known to use as a water-absorbing substance for hygiene products such as absorbent articles. Such a tropolone derivative is more safe than the additives conventionally used as stabilizers for superabsorbent polymers and has a high ability to prevent decomposition / degradation of superabsorbent polymers.

Examples of the tropolone derivative include tropolone, β-tsuyapurisin, γ-tsuyaprisin, β-drabulin and methyl 6-isopropyltropolone-4-carboxylate, and their sodium salts and potassium salts. It is not limited. Of these, β-tsuyapurisin and γ-tsuyapurisin are preferably used. In particular, β-tsuyapurisin is added / used as a fragrance such as a nourishing / hair-growth agent, toothpaste, fragrance, external preparation, bath agent, shampoo and conditioner, and is preferable since it is a biologically safe compound. As the tropolone derivative, a synthetic product or a semi-synthetic product may be used, or naturally occurring Hiba oil or cypress extract oil containing the tropolone derivative may be used as it is or may be purified and used. . These tropolone derivatives may be used alone or in combination of two or more.

In order to dispose the chelating agent compound in the absorber, the means and form are not particularly limited as long as the chelating agent compound can be preferably uniformly arranged in the absorber. Then, it suffices to add the above chelating agent compound to the super absorbent polymer constituting the absorbent body or the hydrophilic fiber material such as paper or pulp. The addition of the chelating agent compound can be performed by adding the chelating agent compound as it is or as a solution obtained by dissolving or dispersing it in a solvent such as ethanol or water. Among them, a method of adding the chelating agent compound in the production process of the superabsorbent polymer, the superabsorbent polymer is added to the solution of the chelating agent compound, and stirred, the chelating agent to the superabsorbent polymer A method of containing a compound,
Alternatively, after the superabsorbent polymer is sprayed on the absorbent paper or pulp sheet made of the hydrophilic fiber, the chelator compound is contained in the superabsorbent polymer by a method of spraying the chelator compound. It is preferable to use the superabsorbent polymer because it has a great effect of preventing deterioration and decomposition of the swollen gel of the superabsorbent polymer with time.

The absorbent article of the present invention comprises a liquid-permeable top sheet, a liquid-impermeable back sheet, and the above-mentioned absorber disposed between these sheets, and specifically, , Disposable diapers for infants, adults, or incontinent persons (flat type or pants type), and feminine sanitary napkins (with or without wings). The structure of the disposable diaper and the sanitary napkin, etc., can employ various structures similar to the conventionally known structure, and the topsheet and the backsheet materials etc. that have been conventionally used are also used. It can be used without particular limitation.

The absorbent article of the present invention is for infants, adults or incontinent persons who have a large amount of excretion and the deterioration / degradation of the swollen gel of the superabsorbent polymer is more noticeable and which has a long contact time with urine. Particularly effective in disposable diapers.

[0051]

EXAMPLES The absorbent article of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The reagents used in the examples and comparative examples are generally commercially available reagents. However, N-acylated glutamic acid Na salt is manufactured by Ajinomoto Co .; Amisoft HS-21 and β-tsuyapurisin are Takasago International Corporation.
Manufactured by, Citric acid monoalkylamide Na salt, citric acid monoalkyl ester Na salt, citric acid monooleyl ester Na salt, alkylmalonic acid, N-alkyl-N′-carboxymethylaspartic acid and monoalkylphosphoric acid ester, monooleyl The phosphoric acid ester and the N-acylated aspartic acid K salt used were those synthesized by a conventional method.

With respect to the chelating agent compounds used in Examples and Comparative Examples, the solubility of Cu salt and the value of pKCu are shown in Table 1. pKCu is calculated by the following operation.
That is, the Cu ion electrode method (Orion pH / ion analyzer, Cu ion electrode) is used, and the solution is a 0.1 M triethanolamine-hydrochloric acid (pH 8) buffer solution. First, using CuCl ₂ · 2H ₂ O, a standard copper ion buffer solution (400, 320, 240, 160, 80 pp
m (Cu ²⁺ conversion)) and prepare a calibration curve with a Cu ion electrode. Next, the sample (0.1 g weighing) is dissolved in a buffer solution (100 ml) using a measuring flask. 0.05M CuCl ₂ · 2H was added to this sample solution.
0.6 ml of ₂ O buffer solution (pH 8) was added dropwise from the buret, and the potential of the Cu ion electrode at that time was read.
The titration is performed up to a potential exceeding 400 ppm (Cu ²⁺ equivalent), and at the same time, blank measurement is also performed. The free Cu ²⁺ ion concentration is calculated from the potential and the value is used to correct the change in the liquid volume of the system due to titration. It is calculated from Equation 1 assuming that a 1: 1 mole complex is formed when equimolar Cu is added to the sample.

[0053]

[Equation 1]

[0054]

[Table 1]

[Example 1] 100 g of a super absorbent polymer (trade name "Poise SA-20", manufactured by Kao Corporation) containing a partially neutralized polyacrylic acid salt crosslinked product as a main component was placed in a double-arm kneader, As a chelating agent compound while stirring, β
100% 0.1 wt% ethanol solution of tsuyapurisin
g was added, and the mixture was sufficiently stirred and mixed to allow β-tsuyaprisin to be absorbed in the superabsorbent polymer, and then dried under reduced pressure to obtain granular superabsorbent polymer (1) containing β-tsuyapurisin. Next, pulp was laminated so that the basis weight was 200 g / m ² , and a pulp sheet of 300 mm (width) × 410 mm (length) × 5 mm (thickness) was obtained, and the central surface of the obtained pulp sheet The above super absorbent polymer (1)
8g evenly over an area of 150mm (width) x 410mm (length), and then on both left and right edges [75mm each
(Area of (width) × 410 (length)) is turned inward (on the central portion on which the superabsorbent polymer is sprayed), and is overlapped so that the left and right side edges are in contact with each other, and β-tyapurisin is contained. An absorbent body (1) in which a super absorbent polymer was sandwiched between pulp sheets was obtained. The absorbent body (1) thus obtained was sandwiched between one polyethylene film as a back sheet and one polypropylene nonwoven fabric as a top sheet to obtain an absorbent article (1) (disposable diaper) of the present invention.

Example 2 As a chelating agent compound, β was used.
-Absorptive article (2) of the present invention was obtained in the same manner as in Example 1 except that 100 g of 0.1 wt% ethanol solution of tsuyapurisin Na salt was used.

Example 3 The same procedure as in Example 1 was carried out except that 100 g of a 0.1% by weight aqueous solution of a citric acid monoalkylamide Na salt (having 18 carbon atoms in the alkyl group) was used as the chelating agent compound. Thus, the absorbent article (3) of the present invention was obtained.

Example 4 As a super absorbent polymer,
Example 1 was repeated except that "Diawet" (trade name, manufactured by Mitsubishi Yuka) was used and 10 g of a 1% by weight aqueous solution of acetylacetone was used as the chelating agent compound.
The absorbent article (4) of the present invention was obtained.

Example 5 As a chelating agent compound, 10 g of a 1% by weight aqueous solution of a citric acid monoalkylamide Na salt (having 16 carbon atoms in the alkyl group) was used.
The absorbent article (5) of the present invention was obtained in the same manner as in Example 1.

Example 6 As a chelating agent compound, N
2% by weight aqueous solution of -alkyl-N'-carboxymethylaspartic acid (alkyl group having 18 carbon atoms) 2
An absorbent article (6) of the present invention was obtained in the same manner as in Example 1 except that 5 g was used.

Example 7 As a chelating agent compound, a monoalkyl phosphate ester (alkyl group having 1 carbon atom) was used.
An absorbent article (7) of the present invention was obtained in the same manner as in Example 1 except that 10 g of a 10% by weight aqueous solution of 2) was used.

Example 8 The present invention was conducted in the same manner as in Example 1 except that 5 g of a 5 wt% aqueous solution of monooleyl phosphate (alkenyl group having 18 carbon atoms) was used as the chelating agent compound. Absorbent article (8) was obtained.

Example 9 The same as Example 1 except that as the chelating agent compound, an aqueous solution obtained by dissolving 0.1 g of citric acid monoalkyl ester Na salt (having 18 carbon atoms in the alkyl group) in 20 g of water was used. Then, the absorbent article (9) of the present invention was obtained.

Example 10 As a chelating agent compound,
The absorbent article of the present invention (10) was used in the same manner as in Example 1 except that a dispersion liquid containing 0.5 g of sodium monooleyl ester of citric acid (alkyl group having 18 carbon atoms) in 50 g of water was used. ) Got.

Example 11 As a chelating agent compound,
Alkyl malonic acid (alkyl group has 16 carbon atoms) 1g
Absorbent article (11) of the present invention was obtained in the same manner as in Example 1 except that 10 g of water was used for dispersion.

Example 12 As a chelating agent compound,
An absorbent article (12) of the present invention was obtained in the same manner as in Example 1 except that 10 g of a 20 wt% aqueous solution of N-acylated glutamic acid 2Na salt (having 18 carbon atoms in the alkyl group) was used. .

Example 13 As a chelating agent compound,
Except that 5 g of a 10 wt% aqueous solution of N-acylated aspartic acid K salt (having 16 carbon atoms in the alkyl group) was used,
The absorbent article (13) of the present invention was obtained in the same manner as in Example 1.

Example 14 Pulp was laminated so that the basis weight was 200 g / m ² , and 300 mm (width) × 410 m
A pulp sheet of m (length) × 5 mm (thickness) was obtained, and a superabsorbent polymer (trade name “Poise SA-20”, manufactured by Kao Corporation) was added to the center surface of the obtained pulp sheet.
Uniformly spraying 8 g on an area of mm (width) × 410 mm (length) to form a superabsorbent polymer layer, and 0.1% by weight of β-tsuyapurisin as a chelating agent compound on the superabsorbent polymer layer upper surface. 8 g of an ethanol solution was sprayed, and then the left and right edges were folded back inwardly in the same manner as in Example 1 to obtain an absorber (14) containing β-yauplysin. An absorbent article (14) of the present invention was obtained in the same manner as in Example 1 except that the obtained absorbent body (14) was used instead of the absorbent body (1).

Example 15 As a chelating agent compound,
An absorbent article (15) of the present invention was obtained in the same manner as in Example 14 except that 8 g of a 0.1 wt% ethanol solution of β-tsuyapricin Na salt was used.

Example 16 As a chelating agent compound,
The absorbent article of the present invention (1) was used in the same manner as in Example 14 except that 8 g of a 0.1 wt% aqueous solution of a citric acid monoalkylamide Na salt (having 18 carbon atoms in the alkyl group) was used.
6) was obtained.

Example 17 As a super absorbent polymer,
Absorbency of the present invention was obtained in the same manner as in Example 14 except that "Diawet" (trade name, manufactured by Mitsubishi Yuka) was used and 0.8 g of a 1% by weight aqueous solution of acetylacetone was used as the chelating agent compound. Article (17) was obtained.

Example 18 As a chelating agent compound,
In the same manner as in Example 14 except that 0.8 g of a 1% by weight aqueous solution of citric acid monoalkylamide Na salt (alkyl group having 16 carbon atoms) was used, the absorbent article (1
8) was obtained.

Example 19 As a chelating agent compound,
2% by weight aqueous solution of N-alkyl-N'-carboxymethylaspartic acid (alkyl group having 18 carbon atoms) 2
An absorbent article (19) of the present invention was obtained in the same manner as in Example 14 except that g was used.

Example 20 As a chelating agent compound,
Other than using 0.8 g of a 10 wt% aqueous solution of a monoalkyl phosphate ester (having 12 carbon atoms in the alkyl group),
The absorbent article (20) of the present invention was prepared in the same manner as in Example 14.
I got

Example 21 As a chelating agent compound,
Except that 0.4 g of a 5 wt% aqueous solution of monooleyl phosphate (alkenyl group having 18 carbon atoms) was used,
The absorbent article (21) of the present invention was prepared in the same manner as in Example 14.
I got

Example 22 As a chelating agent compound,
The absorbent article (22) of the present invention was prepared in the same manner as in Example 14 except that an aqueous solution prepared by dissolving 0.008 g of sodium salt of citric acid monoalkyl ester (having 18 carbon atoms in the alkyl group) in 1 g of water was used. Obtained.

Example 23 As a chelating agent compound,
The absorbent article of the present invention (23) was prepared in the same manner as in Example 14 except that 0.04 g of sodium monooleyl citrate (alkyl group having 18 carbon atoms) was dispersed in 1 g of water. ) Got.

Example 24 As a chelating agent compound,
Alkyl malonic acid (alkyl group has 16 carbon atoms) 0.
An absorbent article (24) of the present invention was obtained in the same manner as in Example 14 except that a dispersion liquid obtained by dispersing 08 g in 1 g of water was used.

Example 25 As a chelating agent compound,
The absorbent article (25) of the present invention was obtained in the same manner as in Example 14 except that 0.8 g of a 20 wt% aqueous solution of N-acylated glutamic acid 2Na salt (having 18 carbon atoms in the alkyl group) was used. It was

Example 26 As a chelating agent compound,
The absorbent article (2 of the present invention was prepared in the same manner as in Example 14 except that 0.4 g of a 10% by weight aqueous solution of N-acylated aspartic acid K salt (having 16 carbon atoms in the alkyl group) was used.
6) was obtained.

Example 27 Pulp was laminated so that the basis weight was 200 g / m ² , and 300 mm (width) × 410 m
A pulp sheet of m (length) × 5 mm (thickness) was obtained, and a superabsorbent polymer (trade name “Poise SA-20”, manufactured by Kao Corporation) was added to the center surface of the obtained pulp sheet.
8g is evenly spread over an area of mm (width) x 410mm (length), and then left and right side edges (each 75mm (width) x 4)
A 10 mm (length) area was folded inward (on the central portion where the super absorbent polymer was sprinkled) and the layers were overlapped so that the left and right edges were in contact with each other. Next, a 0.1 wt% ethanol solution of the chelating agent compound β-tsuyaprisin was sprayed onto the upper surface of the superposed pulp sheets with 8 g of a spray, and after drying, an absorber (27) containing β-tsuyapricin was obtained. An absorbent article (27) of the present invention was obtained in the same manner as in Example 1 except that the obtained absorbent body (27) was used instead of the absorbent body (1).

[Example 28] As a chelating agent compound,
An absorbent article (28) of the present invention was obtained in the same manner as in Example 27, except that 8 g of a 0.1 wt% ethanol solution of β-tsuyapricin Na salt was used.

[Example 29] As a chelating agent compound,
The absorbent article of the present invention (2) was used in the same manner as in Example 27, except that 8 g of a 0.1% by weight aqueous solution of citric acid monoalkylamide Na salt (alkyl group having 18 carbon atoms) was used.
9) was obtained.

Example 30 As a super absorbent polymer,
Absorbency of the present invention was obtained in the same manner as in Example 27, except that "Diawet" [trade name, manufactured by Mitsubishi Yuka] was used and 0.8 g of a 1% by weight aqueous solution of acetylacetone was used as the chelating agent compound. An article (30) was obtained.

Example 31 As a chelating agent compound,
The absorbent article (3) of the present invention was prepared in the same manner as in Example 27, except that 0.8 g of a 1% by weight aqueous solution of a citric acid monoalkylamide Na salt (having 16 carbon atoms in the alkyl group) was used.
1) was obtained.

Example 32 As a chelating agent compound,
2% by weight aqueous solution of N-alkyl-N'-carboxymethylaspartic acid (alkyl group having 18 carbon atoms) 2
An absorbent article (32) of the present invention was obtained in the same manner as in Example 27 except that g was used.

Example 33 As a chelating agent compound,
Other than using 0.8 g of a 10 wt% aqueous solution of a monoalkyl phosphate ester (having 12 carbon atoms in the alkyl group),
The absorbent article (33) of the present invention was prepared in the same manner as in Example 27.
I got

Example 34 As a chelating agent compound,
Except that 0.4 g of a 5 wt% aqueous solution of monooleyl phosphate (alkenyl group having 18 carbon atoms) was used,
The absorbent article (34) of the present invention was prepared in the same manner as in Example 27.
I got

Example 35 As a chelating agent compound,
The absorbent article (35) of the present invention was prepared in the same manner as in Example 27, except that an aqueous solution prepared by dissolving 0.008 g of a sodium salt of citric acid monoalkyl ester (having 18 carbon atoms in the alkyl group) in 1 g of water was used. Obtained.

Example 36 As a chelating agent compound,
The absorbent article of the present invention (36) was used in the same manner as in Example 27, except that 0.04 g of sodium salt of citric acid monooleyl ester (alkyl group having 18 carbon atoms) was dispersed in 1 g of water. ) Got.

Example 37 As a chelating agent compound,
Alkyl malonic acid (alkyl group has 16 carbon atoms) 0.
An absorbent article (37) of the present invention was obtained in the same manner as in Example 27 except that the dispersion liquid obtained by dispersing 08 g in 1 g of water was used.

Example 38 As a chelating agent compound,
The absorbent article (38) of the present invention was prepared in the same manner as in Example 27 except that 0.8 g of a 20 wt% aqueous solution of N-acylated glutamic acid 2Na salt (having 18 carbon atoms in the alkyl group) was used. Obtained.

Example 39 As a chelating agent compound,
Absorbent article (39) of the present invention in the same manner as in Example 27, except that 0.4 g of a 10 wt% aqueous solution of N-acylated aspartic acid K salt (having 16 carbon atoms in the alkyl group) was used. Got

Comparative Example 1 Pulp was laminated so that the basis weight was 200 g / m ² , and 300 mm (width) × 410 mm
A pulp sheet of (length) × 5 mm (thickness) is obtained, and a superabsorbent polymer (trade name “Poise SA-20”, manufactured by Kao Corporation) is 150 m on the surface of the central portion of the obtained pulp sheet.
8g is evenly spread over an area of m (width) x 410mm (length), and then left and right side edges (each 75mm (width) x 41).
The comparative absorbent body (1) was obtained by folding back with the area of 0 mm (length) facing inward (on the central portion on which the superabsorbent polymer was sprinkled) and stacking so that the left and right edges were in contact with each other. A comparative product (1) was obtained in the same manner as in Example 1 except that the obtained comparative absorbent (1) was used instead of the absorbent (1).

Comparative Example 2 As a super absorbent polymer,
A comparative product (2) was obtained in the same manner as in Comparative Example 1 except that "Diawet" [trade name, manufactured by Mitsubishi Yuka] was used.

Comparative Example 3 100 g of a superabsorbent polymer (trade name "Poise SA-20", manufactured by Kao Corporation) containing a partially neutralized polyacrylic acid salt crosslinked product as a main component was placed in a double-arm kneader. While stirring, 100 g of a 1.0 wt% aqueous solution of citric acid 3Na salt was added as a chelating agent compound, and the mixture was sufficiently stirred and mixed to be absorbed by the superabsorbent polymer, and then dried under reduced pressure to obtain granular citric acid. A super absorbent polymer (40) containing 3Na salt was obtained. Next, the basis weight 20
300 mm by stacking pulp so that the weight becomes 0 g / m ^2.
A pulp sheet of (width) × 410 mm (length) × 5 mm (thickness) is obtained, and the super absorbent polymer (40) is 150 mm (width) × 410 on the surface of the central portion of the obtained pulp sheet.
8 g uniformly over an area of mm (length), and then the left and right side edges (each area of 75 mm (width) x 410 mm (length)) are directed inward (the above-mentioned super absorbent polymer is sprayed). After being folded back (on the central part), a laminated comparative absorbent body (3) was obtained so that the left and right edges were in contact with each other. A comparative product (3) was obtained in the same manner as in Example 1 except that the comparative absorbent body (3) obtained was used instead of the absorbent body (1).

Comparative Example 4 A comparative product (4) was obtained in the same manner as Comparative Example 3 except that an aqueous solution prepared by dissolving 0.1 g of sodium tripolyphosphate in 10 g of water was used as the chelating agent compound.

[Comparative Example 5] As a chelating agent compound, 0.1 g of ethylenediaminetetraacetic acid-4 Na salt was added to 10 parts of water.
Comparative product (5) was obtained in the same manner as Comparative Example 3 except that an aqueous solution dissolved in g was used.

[Comparative Example 6] 100 g of a super absorbent polymer (trade name "Diawet" trade name, manufactured by Mitsubishi Petrochemical Co., Ltd.) containing a partially neutralized polyacrylate cross-linked body as a main component was placed in a double-arm kneader, While stirring, 100 g of an aqueous solution of 1.0% by weight citric acid 3Na salt was added as a chelating agent compound,
After sufficiently stirring and mixing to allow the superabsorbent polymer to absorb,
It was dried under reduced pressure to obtain a superabsorbent polymer (43) containing granular 3Na citrate. Next, basis weight 200g /
300 mm (width) by stacking pulp so that m ²
A pulp sheet of x410 mm (length) x5 mm (thickness) was obtained, and the superabsorbent polymer (43) was 150 mm (width) x410 mm on the surface of the central part of the obtained pulp sheet.
8g is evenly spread over the area of (length), and then the left and right side edges (areas of 75mm (width) x 410 (length) respectively) are directed inward (the above center where the super absorbent polymer is sprayed). It was folded back (on the part), and a laminated comparative absorbent body (6) was obtained so that the left and right edges were in contact with each other. A comparative product (6) was obtained in the same manner as in Example 1 except that the comparative absorbent body (6) obtained was used instead of the absorbent body (1).

Comparative Example 7 A comparative product (7) was obtained in the same manner as Comparative Example 6 except that an aqueous solution prepared by dissolving 0.1 g of tripolyphosphoric acid Na salt in 10 g of water was used as the chelating agent compound.

Comparative Example 8 As a chelating agent compound, 0.1 g of ethylenediaminetetraacetic acid-4Na salt was added to 10 parts of water.
Comparative product (8) was obtained in the same manner as Comparative Example 6 except that an aqueous solution dissolved in g was used.

The absorbent articles obtained in Examples 1 to 39 and Comparative Examples 1 to 8 were evaluated according to the following evaluation criteria.
Each was evaluated. The results are shown in [Table 2] (Example 1)
To 20), [Table 3] (Examples 21 to 39) and [Table 4]
(Comparative Examples 1 to 8).

[Liquid Return Amount] 150 g of physiological saline containing 0.05% by weight of sodium L-ascorbate was absorbed in the absorbent article, and the absorbent article was sealed with a polyethylene pack for 6 hours at 40 ° C. 2 minutes after storage
The amount of physiological saline returned from the inside to the topsheet surface was measured by pressurizing with a load of 35 g / cm ² .

[Stability of swollen gel] L at 0.05% by weight
After absorbing 150 g of physiological saline containing sodium ascorbate into the absorbent article, sealing the absorbent article with a polyethylene pack and storing at 40 ° C. for 6 hours,
Observe the appearance of swollen gel of super absorbent polymer with the naked eye,
The state (stability) was evaluated according to the following four grades. ⊚: The swollen gel has neither fluidity nor spinnability and its shape has not changed. ◯: The swollen gel has some fluidity and spinnability,
The shape has not changed. (Triangle | delta): Although it has not yet been dissolved, the swollen gel has fluidity and spinnability, and its shape is changed to make it unclear. X: Partially dissolved, half or more of the swollen gels have changed shape, and the original shape is not left.

[0105]

[Table 2]

[0106]

[Table 3]

[0107]

[Table 4]

[0108]

EFFECT OF THE INVENTION The absorbent article of the present invention is excellent in absorption characteristics because the decrease in the body fluid retention of the absorbent body containing the superabsorbent polymer with time is suppressed. More specifically, the absorbent article of the present invention, since the body fluid retention of the absorbent body containing the superabsorbent polymer does not decrease over time, there is little liquid return, and liquid leakage does not occur, for infants, It is particularly effective as a disposable diaper for adults or incontinence, or a sanitary napkin for women. Further, the absorbent article of the present invention, in the absorbent body, by the action of the chelating agent compound arranged in the absorbent body, deterioration and decomposition of the swollen gel of the superabsorbent polymer are suppressed even after absorbing body fluid. The content ratio of the super absorbent polymer can be increased. Therefore, the absorbent article of the present invention can be made compact and have good portability, excellent wearability, and excellent absorption characteristics.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location C08K 5/00 KAJ C08L 101/14 LTB (72) Inventor Tsuyoshi Konno 2606 Akabane, Kai-cho, Haga-gun, Tochigi Prefecture Kao Institute of Stock Research

Claims (8)

[Claims] 1. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body containing a superabsorbent polymer disposed between these sheets, the absorbent body comprising: Contains a chelating agent compound having a site capable of forming a chelate with Cu ions and having a solubility of a Cu salt in physiological saline of 25 ° C. of 0.01% by weight or less. An absorbent article in which the proportion is 0.0001 to 30 parts by weight relative to 100 parts by weight of the superabsorbent polymer. 2. The common logarithmic value (p of the chelating stability constant of the chelating agent compound with Cu ions at 25 ° C.).
The absorbent article according to claim 1, wherein KCu) is 3 or more. 3. The chelating agent compound has 6 carbon atoms.
2. A hydrophobic part comprising the above saturated or unsaturated hydrocarbon group, and a hydrophilic part having at least one group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a hydroxyl group and a phosphoric acid group. Or the absorbent article according to 2. 4. The chelating agent compound is a polyvalent carboxylic acid derivative, a hydroxycarboxylic acid derivative, an iminodiacetic acid derivative, an organic acid amide derivative, an N-acylated amino acid derivative, a phosphoric acid ester derivative, a phosphonic acid derivative or a polyvalent phosphon. The absorbent article according to claim 3, which is an acid derivative. 5. The chelating agent compound is citric acid monoalkylamide, citric acid monoalkenylamide, citric acid monoalkyl ester, citric acid monoalkenyl ester, alkylmalonic acid, alkenylmalonic acid, N-.
Acylated glutamic acid, N-acylated aspartic acid,
N-alkyl-N′-carboxymethylaspartic acid, N-alkenyl-N′-carboxymethylaspartic acid, monoalkylphosphoric acid ester, monoalkenylphosphoric acid ester or their alkali metal salts or alkaline earth metal salts, The absorbent article according to claim 4. 6. The absorbent article according to claim 1, wherein the chelating agent compound is a β-diketone derivative. 7. The absorbent article according to claim 1, wherein the chelating agent compound is a tropolone derivative. 8. The absorbent article according to claim 1, wherein the water-absorbent polymer is a partially crosslinked polymer compound having a carboxyl group or a salt thereof or a partially crosslinked polysaccharide.