JP5825888B2 - Water-absorbent resin composition, absorber and absorbent article - Google Patents

Description

  The present invention relates to a water-absorbent resin composition that is excellent in antibacterial and deodorizing performance, can be handled safely, and has excellent gel stability. Moreover, this invention relates to the absorber manufactured using this water absorbent resin composition, and the absorbent article manufactured using this absorber.

Conventionally, water-absorbing resins have been used for sanitary materials such as disposable diapers, sanitary napkins, incontinence pads, urine absorbing materials for pets, civil engineering and building materials such as packing materials, food freshness-keeping materials such as drip absorbents and cold insulation materials, It is used in various fields such as agricultural and horticultural articles such as soil water retention materials.
Absorbent articles represented by sanitary materials such as disposable diapers are a flexible liquid-permeable surface sheet (top sheet) in which an absorbent that absorbs liquid such as body fluid is disposed on the side in contact with the body, and a surface sheet And a liquid impervious back sheet (back sheet) disposed on the opposite side. Usually, an absorber consists of a mixture of a water absorbing resin and a hydrophilic fiber.
In the absorbent article, there is a problem that an unpleasant odor is generated when a body fluid, particularly human urine is absorbed. These odors are rotting odors that are produced when bacteria present in the skin and digestive tract produce enzymes that break down components of body fluids such as urea and proteins, and the components of body fluids are decomposed by the enzymes. It is believed that there is.

  In order to suppress the generation of these odors, absorbents mixed with odorous component adsorbents such as activated carbon and zeolite (see, for example, Patent Documents 1 and 2) and the above bacteria are sterilized, and the rot odor increases over time. A composition comprising an inorganic antibacterial agent in which an antibacterial metal such as silver, copper or zinc is supported on an inorganic compound and a water-absorbing resin has been proposed (for example, see Patent Document 3). As another means for suppressing the generation of odor, a water absorbent (for example, see Patent Document 4) composed of a sterilizing agent such as a quaternary ammonium salt and a water absorbent resin has been proposed.

  In addition, in order to suppress the generation of odor, antibacterial properties obtained by crosslinking and polymerizing a phosphonium salt monomer component having antibacterial properties and a monomer component that can be copolymerized with the phosphonium salt monomer component and become a superabsorbent resin after polymerization. A highly water-absorbent resin has been proposed (see, for example, Patent Document 5).

On the other hand, human urine contains several factors that degrade the water-absorbent resin. When the water-absorbent resin absorbs human urine, the gel deteriorates (the strength decreases or the gel decomposes). ) Occurs. As the gel deteriorates, gaps between the gels are blocked, resulting in gel blocking that prevents liquid penetration, resulting in poor liquid diffusivity, and human urine when used in absorbent articles. Cause leakage. Moreover, when the soluble component of a gel elutes by decomposition | disassembly of a gel, it causes a rash.
Furthermore, since absorbent articles such as paper diapers are often worn for a long time, such as nighttime use, a water-absorbing resin that exhibits gel stability for a long time after absorbing human urine is required.

JP 2001-037805 A Japanese National Patent Publication No. 11-512946 JP-T-2001-505237 Japanese Unexamined Patent Publication No. 2000-079159 JP-A-8-092020

  The odor component adsorbents and inorganic antibacterial agents disclosed in Patent Documents 1 to 3 are inferior in affinity with the water-absorbent resin, and therefore adsorbents and antibacterial agents are generated when manufacturing absorbent articles such as disposable diapers. There is a problem that the working environment during production deteriorates due to dust. In addition, the water-absorbing agent comprising a bactericidal agent such as a quaternary ammonium salt and a water-absorbing resin disclosed in Patent Document 4 may cause inflammation due to contact of the bactericidal agent with the skin and mucous membrane. The antibacterial highly water-absorbent resin disclosed in Patent Document 5 has a disadvantage that it is not economical because the monomer component having antibacterial properties is expensive. Moreover, in these patent documents, the gel stability of the water-absorbent resin composition is not considered.

  An object of the present invention is to provide a water-absorbent resin composition that is excellent in antibacterial and deodorizing performance, can be handled safely, and has excellent gel stability. Moreover, an object of this invention is to provide the absorber manufactured using this water absorbent resin composition, and the absorbent article manufactured using this absorber.

The present invention is a water absorbent resin composition containing a water absorbent resin and an Asteraceae plant extract , wherein the content of the Asteraceae plant extract is 0.005 to 100 parts by mass of the water absorbent resin. It is a water-absorbent resin composition that is 5 parts by mass .

  The water-absorbent resin composition according to the present invention has an excellent antibacterial and deodorizing performance, and has a high safety and no problem of dust generation. And has excellent gel stability.

  The water-absorbing resin composition according to the present invention contains a water-absorbing resin and an Asteraceae plant extract.

  Examples of the water-absorbing resin include a crosslinked product of partially neutralized acrylic acid polymer, a crosslinked product of starch-acrylate graft copolymer, a crosslinked product of vinyl alcohol-acrylate copolymer, and maleic anhydride. Examples include a grafted product of grafted polyvinyl alcohol, a crosslinked isobutylene-maleic anhydride copolymer, a saponified product of vinyl acetate-acrylic acid ester copolymer, and the like. Among these water-absorbing resins, a cross-linked product of a partially neutralized acrylic acid polymer is preferable because it absorbs a large amount of liquid and can retain the absorbed liquid in the molecule even under some load. .

  The manufacturing method of the said water absorbing resin is not specifically limited, For example, the reverse phase suspension polymerization method, the aqueous solution polymerization method, etc. are mentioned.

  Examples of the Asteraceae plants include chrysanthemum (iegiku), arnica, pear, chamomile, kawara mugwort, stevia, sorghum, yarrow, eucalyptus, marigold, and yacon. Among these asteraceae plants, stevia, milk moth and dandelion are preferred because they are effective in antibacterial properties and safety, and gel stability of the water-absorbent resin composition.

  The part of the plant used as the raw material of the extract is not particularly limited, and examples thereof include leaves, stems, flowers, buds, roots, seeds, fruits, peels, fruit nuclei, above-ground parts, whole grasses, or a mixture thereof. Among these, it is particularly preferable to use leaves and flowers. The raw material may be subjected to extraction as it is, but from the viewpoint of extraction efficiency, a material subjected to treatment such as drying and pulverization is preferable.

  As the Asteraceae plant extract, one extracted by a method generally used for plant extraction may be used, or a commercially available product may be used.

  Examples of the method for taking out the extract from the Asteraceae plant include a method in which the raw material is immersed in an extraction solvent. In this case, stirring may be performed to increase extraction efficiency, or homogenization may be performed in an extraction solvent. As the extraction solvent, water, a hydrophilic organic solvent, or a mixed solvent thereof can be used. Examples of the hydrophilic organic solvent include lower alcohols such as methanol, ethanol, propanol and isopropanol; polyhydric alcohols such as 1,3-butylene glycol, propylene glycol and glycerin; ketones such as acetone and methyl ethyl ketone; diethyl ether and dipropyl ether. Ethers such as ethyl ester and esters such as ethyl acetate and butyl acetate are used. The extraction temperature is preferably about 5 ° C. to the boiling point of the extraction solvent. The extraction time varies depending on the type of raw material, extraction solvent, and extraction temperature, but is preferably about 4 hours to 14 days.

  The amount of the Asteraceae plant extract used is preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the water absorbent resin. From the viewpoint of exhibiting sufficient antibacterial deodorization properties as a water absorbent resin composition and gel stability of the resulting water absorbent resin composition, 0.005 parts by mass or more is preferable, From the viewpoint of suppressing the odor of the Asteraceae plant extract itself, 5 parts by mass or less is preferable. As for the usage-amount of the said Asteraceae plant extract, it is more preferable that it is 0.05-3 mass parts, and it is still more preferable that it is 0.1-2 mass parts.

The water absorbent resin composition according to the present invention can be produced, for example, by the following methods (a) to (c). The water absorbent resin composition according to the present invention is produced by these methods. It is not limited to.
(A) A method in which a asteraceae plant extract is directly spray mixed with a water-absorbent resin.
(B) A method in which a water-absorbent resin is spray-mixed with an aqueous solution or an alcohol solution of an Asteraceae plant extract and dried.
(C) A method of adding a water-absorbent resin and a asteraceae plant extract to a solvent that does not swell the water-absorbent resin, and removing the solvent after stirring and mixing.
In addition, it is preferable that the Asteraceae plant extract used for this invention is a liquid form from a viewpoint of suppressing dust generation.

  The absorber containing the water-absorbent resin composition according to the present invention and hydrophilic fibers is also one aspect of the present invention.

  Examples of the hydrophilic fiber include cellulose fiber, artificial cellulose fiber, and hydrophilic synthetic fiber.

  As a preferable aspect of the absorbent body according to the present invention, for example, a mixed dispersion obtained by mixing the water-absorbent resin composition according to the present invention and the hydrophilic fiber so as to have a uniform composition, Examples include a sandwich structure in which a water-absorbent resin composition is sandwiched between layered hydrophilic fibers.

  To the absorbent body according to the present invention, an adhesive binder such as a heat-fusible synthetic fiber, a hot melt adhesive, or an adhesive emulsion may be added in order to improve the shape retention of the absorbent body.

  An absorbent article in which the absorbent according to the present invention is held between the liquid permeable sheet and the liquid impermeable sheet is also one aspect of the present invention.

  Examples of the liquid permeable sheet include air-through type, spun bond type, chemical bond type, needle punch type nonwoven fabrics made of fibers such as polyethylene, polypropylene, and polyester.

  Examples of the liquid impermeable sheet include synthetic resin films made of resins such as polyethylene, polypropylene, and polyvinyl chloride.

  Absorbent articles according to the present invention include, for example, sanitary materials such as disposable diapers, sanitary napkins and incontinence pads, urine absorbent materials for pets, civil engineering and building materials such as packing materials, food freshness such as drip absorbents and cold insulation materials. It is suitably used for agricultural and horticultural articles such as holding materials and soil water retaining materials.

  Hereinafter, the present invention will be described in more detail based on synthesis examples, production examples, examples, and comparative examples, but the present invention is not limited only to such examples.

[Synthesis example]
A 2 L round bottom cylindrical separable flask equipped with a stirrer, a two-stage paddle blade, a reflux condenser, a dropping funnel and a nitrogen gas introduction tube was prepared. To this flask, 280 g of n-heptane was taken, 0.83 g of sucrose stearate ester (Mitsubishi Chemical Foods Co., Ltd., Ryoto Sugar Ester S-370) was added, and the temperature was raised to 80 ° C. with stirring to sucrose. After the stearic acid ester was dissolved, it was cooled to 50 ° C.
On the other hand, 92 g (1.02 mol) of 80% by mass acrylic acid aqueous solution was placed in a 500 mL Erlenmeyer flask, and 146.0 g of 21% by mass sodium hydroxide aqueous solution was added dropwise while cooling from the outside. After neutralization, 0.074 g (0.27 mmol) of potassium persulfate as a radical polymerization initiator and 9.2 mg (0.06 mmol) of N, N′-methylenebisacrylamide as an internal crosslinking agent were added and dissolved. The first stage monomer aqueous solution was prepared.
After adding the total amount of the first stage monomer aqueous solution to the separable flask and sufficiently replacing the system with nitrogen, the flask was immersed in a 70 ° C. water bath and heated. The first stage polymerization was carried out for 30 minutes to obtain a first stage reaction mixture.
On the other hand, 128.8 g (1.43 mol) of an 80% by weight acrylic acid aqueous solution was placed in another 500 mL Erlenmeyer flask, and 159.0 g of a 27% by weight sodium hydroxide aqueous solution was dropped while cooling from the outside. After neutralization of 75 mol%, 0.10 g (0.37 mmol) of potassium persulfate as a radical polymerization initiator and 12.9 mg (0.08 mmol) of N, N′-methylenebisacrylamide as an internal crosslinking agent Was added and dissolved to prepare a second-stage monomer aqueous solution.
The first-stage reaction mixture was cooled to 25 ° C., and the second-stage monomer aqueous solution at the same temperature was added to the system and absorbed for 30 minutes. At the same time, the system was sufficiently replaced with nitrogen. Thereafter, the flask was again immersed in a 70 ° C. water bath and the temperature was raised, and the second stage polymerization was carried out for 30 minutes.
After polymerization in the second stage, the reaction mixture was heated in an oil bath at 125 ° C., and 222 g of water was extracted out of the system while refluxing n-heptane by azeotropic distillation of n-heptane and water. 3.98 g (0.46 mmol) of a 2% by weight aqueous solution of ethylene glycol diglycidyl ether was added, and a post-crosslinking reaction was performed at 80 ° C. for 2 hours. Thereafter, the reaction mixture was heated in a 125 ° C. oil bath, and n-heptane was evaporated and dried to obtain 225.4 g of a water absorbent resin.

[Production Example 1]
200 g of flowers of the asteraceae, Asteraceae, were dried and pulverized, extracted with stirring in 1 L of 50% by volume ethanol aqueous solution at 20 ° C. for 3 days, and then filtered to obtain a filtrate. The filtrate was concentrated under reduced pressure, sufficiently dried, and then dissolved using a 50% by volume ethanol aqueous solution to obtain a 1% by weight milk scented extract.

[Production Example 2]
500 g of Asteraceae flower, Asteraceae, was dried and pulverized, and extracted by standing in 3 L of 70% by volume ethanol aqueous solution at 20 ° C. for 7 days, followed by filtration to obtain a filtrate. The filtrate was concentrated under reduced pressure, sufficiently dried, and then dissolved using a 50% by volume ethanol aqueous solution to obtain a 5% by weight milk sesame extract.

[Production Example 3]
A 2% by weight dandelion extract was obtained in the same manner as in Production Example 1 except that 200 g of dandelion flowers were used as the Asteraceae plants.

[Production Example 4]
200 g of Stevia leaves of the Asteraceae plant were dried, pulverized, extracted with stirring in 1 L of warm water (50 ° C.) for 5 hours, and then filtered to obtain a filtrate and a filtrate. The filtrate was again extracted by stirring in 1 L of warm water (50 ° C.) for 5 hours, filtered, and the obtained filtrate was mixed with the filtrate obtained in the previous operation. This solution was concentrated under reduced pressure, sufficiently dried, and then dissolved using a 50% by volume ethanol aqueous solution to obtain a 1% by mass stevia extract.

[Example 1]
To 20 g of the water-absorbent resin obtained in the synthesis example, 20 g of the milk sesame extract (1% by mass) obtained in Production Example 1 was sufficiently mixed as an Asteraceae plant extract. Next, this mixture was heated in an oil bath at 100 ° C. for 30 minutes to distill off ethanol and water to obtain 20.2 g of a water absorbent resin composition.

[Example 2]
20 g of the water-absorbent resin obtained in the synthesis example was directly sprayed with 0.6 g of the milk sesame extract (1% by mass) obtained in Production Example 1 as an Asteraceae plant extract and mixed well. Subsequently, this mixture was heated in an oil bath at 100 ° C. for 30 minutes to distill off ethanol and water to obtain 20.0 g of a water absorbent resin composition.

[Example 3]
As the Asteraceae plant extract, 20.7 g of a water-absorbent resin composition was obtained in the same manner as in Example 1 except that 16 g of the milk moth extract (5% by mass) obtained in Production Example 2 was used.

[Example 4]
As an Asteraceae plant extract, 20.3 g of a water-absorbent resin composition was obtained in the same manner as in Example 1 except that 15 g of the dandelion extract (2% by mass) obtained in Production Example 3 was used.

[Example 5]
As a compositae plant extract, 20.0 g of a water-absorbent resin composition was obtained in the same manner as in Example 2, except that 6 g of the stevia extract (1% by mass) obtained in Production Example 4 was used.

[Example 6]
50 g of the water-absorbent resin obtained in the synthesis example was directly sprayed with 0.2 g of the milk sesame extract (1% by mass) obtained in Production Example 1 as an Asteraceae plant extract and mixed well. Next, this mixture was heated in an oil bath at 100 ° C. for 30 minutes to distill off ethanol and water to obtain 50.0 g of a water absorbent resin composition. However, Example 6 is a reference example.

[Example 7]
As an Asteraceae plant extract, 21.1 g of a water-absorbent resin composition was obtained in the same manner as in Example 1, except that 24 g of the milk sesame extract (5% by mass) obtained in Production Example 2 was used. However, Example 7 is a reference example.

[Comparative Example 1]
20 g of the water absorbent resin obtained in the synthesis example was used as it was.

  The gel stability at the time of human urine absorption of the water-absorbent resin composition obtained in the examples and the water-absorbent resin of the comparative example, and the odor sensory test of the absorber were performed by the following methods.

<Gel stability during human urine absorption>
39 g of human urine collected from an adult male was collected in a 100 mL beaker, and 1 g of a water absorbent resin composition or a water absorbent resin was added to prepare a human urine absorbing gel. This human urine absorbing gel was placed in a constant temperature bath at 40 ° C., and the gel stability after 24 hours was evaluated according to the following evaluation criteria. The results are shown in Table 1.
A: The elasticity of the gel is not crushed even when pressed strongly.
B: The gel is elastic, but when pressed hard, it collapses.
C: Although there is a gel shape, it is crushed when lightly pinched.
D: The shape of the gel is broken.

<Odor sensory test of absorber>
(A) Preparation of Absorber After a water absorbent resin composition or a blend of 1 g of a water absorbent resin and 1 g of pulverized pulp is formed on a tissue having a diameter of 5 cm by air-making and stacked on a tissue of the same size An absorber was manufactured by applying a load of 145 kPa for 30 seconds.

(B) Odor sensory test 50 mL of fresh human urine was placed in a 100 mL Meyer flask, 0.25 g of urea and 1 g of pulp collected from used diapers were added, and the solution was allowed to stand for 24 hours to prepare fermented urine. Next, a test solution was prepared by mixing fresh human urine and the above fermented urine at a ratio of 9: 1 (mass ratio) (fresh human urine is sterile, so sufficient odor is required if fermented urine is not mixed) Does not occur).
After putting the absorber obtained in the above (a) into a 250 mL glass bottle, 30 g of the test solution was added to swell the absorber. After adding the test solution, it was immediately sealed and stored at 40 ° C. for 24 hours. After storage, five panelists (A to E) were asked to determine the odor in the 250 mL glass bottle according to the following criteria in accordance with the “standard 6-level odor intensity display method” of the standard criteria, and evaluated with the average value. . The results are shown in Table 1.
5: Strong odor 4: Strong odor 3: Easily recognizable odor 2: Weak odor that understands what kind of odor 1: Slightly detectable odor 0: No odor

The numerical value of the usage-amount of the Asteraceae plant extract in Table 1 is a value (parts by mass) with respect to 100 parts by mass of the water absorbent resin.
As is clear from Table 1, the water-absorbent resin compositions of Examples 1 to 7 are superior to the water-absorbent resin composition of Comparative Example 1 in terms of gel stability during human urine absorption, and to suppress odors. It turns out that it is excellent. In the case of Example 6, since the amount of the Asteraceae plant extract is small, the gel stability at the time of human urine absorption tends to be poor, and the effect of suppressing the unpleasant odor of human urine is small. In the case of Example 7, the unpleasant odor of human urine is suppressed, but the odor of the Asteraceae plant extract itself tends to be strong because there are many Asteraceae plant extracts.
On the other hand, in the comparative example 1, since the Asteraceae plant extract is not mixed, gel stability at the time of human urine absorption is low, and unpleasant odor of human urine cannot be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in antibacterial and deodorizing performance, can be handled safely, and can provide the water absorbing resin composition excellent in gel stability. Moreover, according to this invention, the absorber manufactured using this water absorbent resin composition and the absorbent article manufactured using this absorber can be provided.

Claims (3)

A water absorbent resin composition comprising a water absorbent resin and an Asteraceae plant extract , wherein the content of the Asteraceae plant extract is 0.005 to 5 parts by mass with respect to 100 parts by mass of the water absorbent resin. A water absorbent resin composition . Absorber containing a water absorbent resin composition according to claim 1 Symbol placement and the hydrophilic fiber. An absorbent article in which the absorbent body according to claim 2 is held between a liquid-permeable sheet and a liquid-impermeable sheet.