JP3065573B2 - Method for producing quaternary ammonium base-containing water-absorbing resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a quaternary ammonium base-containing water-absorbent resin. More specifically, a quaternary ammonium base-containing water-absorbent resin having high purity without residual by-products is obtained, and the fourth water-absorbent resin which can be applied to the production of a water-absorbent resin excellent in antibacterial performance and powder fluidity as well as absorption performance The present invention relates to a method for producing a water-absorbent resin containing a quaternary ammonium base.

[0002]

2. Description of the Related Art A water-absorbent resin has an absorption performance, a water retention capability,
Utilizing the gelling ability, absorbent articles such as disposable diapers, incontinence pads, sanitary napkins, breast milk pads, etc., pet sheets, pet floor sand, excrement disposal agents, waste blood gelling agents, drip absorbents It is used in various applications such as a freshness preservative. However, the conventional water-absorbent resin has excellent ability to absorb and retain urine, blood, body fluid, etc., but does not have an antibacterial function.

Therefore, when the conventional water-absorbent resin absorbs liquids such as urine, blood, body fluid, etc., organic substances contained in the liquid to be absorbed are decomposed by fungi and microorganisms, and the decomposed products generate odors and irritate the skin. There is a problem that causes rash and the like. Further, the water-absorbing gel is liable to rot by bacteria in the air, and the rot may emit a bad smell. From the above, from the viewpoints of hygiene and safety, the emergence of a material excellent in both the water absorbing function and the antibacterial function has been desired. In particular, in the case of absorbent articles such as adult paper diapers and incontinent pads used for bedridden elderly and sick people, the problem of bad smell and rash is serious, and a solution is desired. Further, the appearance of a water-absorbent resin having an excellent antibacterial function has been desired also for the purpose of preventing infection by pathogenic bacteria when disposing of used absorbent articles.

As a method of exhibiting an effect similar to the above, a mixture of powders of a water-absorbing resin and zeolite (JP-A-57-25813, JP-A-59-179114)
JP-A-59-189854), a composition in which activated carbon is coated with a water-absorbent resin (JP-A-56-31425), a composition comprising a water-absorbent resin and a deodorant component extracted from a Camellia plant. (Japanese Patent Application Laid-Open No. 60-158861), a water-absorbing resin composition containing a specific antibacterial agent (benzalkonium chloride, chlorhexidine gluconate or a phosphate compound) (Japanese Patent Publication No. 4-17058, Kaihei 5-
No. 179053), and application to these absorbent articles has been proposed.

[0005]

However, the compositions (1) to (2) do not always have a satisfactory odor generation preventing effect or a rot suppressing effect, or have an antibacterial function or a deodorizing function. In order to satisfy the above conditions, it is necessary to post-treat a substance having these functions into a water-absorbent resin, but there is a problem that the powder flowability of the composition obtained by this post-treatment is reduced.

That is, the mixture of the water-absorbing resin and the zeolite can exert a deodorizing effect by adsorbing the generated malodor to some extent, but since both the water-absorbing resin and the zeolite do not have an antibacterial function, the mixture of microorganisms and Deterioration and decay of organic matter by fungi cannot be suppressed, and generation of offensive odor cannot be prevented. Therefore, even when applied to an absorbent article, skin irritation and rash due to decomposition of organic substances could not be suppressed. In addition, the zeolite was separated from the water-absorbent resin by vibration or impact, resulting in an increase in dust generation and variations in the deodorizing function.

In the case of a composition in which activated carbon is coated with a water-absorbing resin, or a composition comprising a water-absorbing resin and a deodorant component extracted from a camellia plant, the deodorant component extracted from the activated carbon and the camellia plant is used. Since it does not show antibacterial function, the result is the same as that of the above zeolite,
Decay of organic matter by microorganisms and fungi could not be suppressed.

The water-absorbent resin composition containing benzalkonium chloride, chlorhexidine gluconate or a phosphate compound has a certain antibacterial activity,
The types of fungi and microorganisms to be used for antibacterial effects are limited and not always satisfactory. In particular, benzalkonium chloride has excellent antibacterial effect against Escherichia coli and the like, but ammonia-producing bacteria (Providentica
Because of its poor antibacterial action against rettgeri), there is a drawback that the effect of suppressing the generation of ammonia odor due to the decomposition of urine and the like by the action of ammonia-producing bacteria is poor. Furthermore, the antibacterial water-absorbing resin composition obtained by treating with these antibacterial agents has a problem that the powder fluidity is significantly reduced depending on the treatment amount of the antibacterial agent.
In addition, when using an adsorbent such as zeolite or activated carbon such as a deodorant extracted from a Camellia plant,
There was a problem that a special operation was required to fix these to the water absorbent resin.

[0009]

DISCLOSURE OF THE INVENTION In view of the above problems, the present inventors have developed an object which is excellent in absorption performance and powder fluidity, exhibits a stable antibacterial effect, and absorbs urine, blood, body fluid and the like. The present inventors have intensively studied a method for producing an antibacterial water-absorbing resin which is useful for absorbent articles used in the above and exhibits an excellent antibacterial action particularly against ammonia-producing bacteria. As a result, by reacting a specific water-absorbent resin with a quaternary ammonium compound, a water-absorbent resin having a quaternary ammonium base can be obtained with high purity. The present inventors have found that the method is extremely suitable as a method for producing a resin, and have reached the present invention.

That is, according to the present invention, the water-absorbent resin (a) having an acid group in the side chain and the quaternary ammonium carbonate (b) are reacted in the presence of water to form at least one of the acid groups in the side chain. A method for producing a quaternary ammonium salt group-containing water-absorbent resin, characterized in that a water-absorbent resin (A) whose part is present in the form of a quaternary ammonium salt is obtained.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the water-absorbent resin (a) is neutralized with an unneutralized acid group in a side chain and / or an alkali metal salt, ammonium salt or amine salt (particularly an alkali metal salt). Those having a modified acid group are preferably used. In this case, among the acid groups in the water-absorbent resin (a), those in which 50 to 80 equivalent%, particularly 60 to 75 equivalent% are neutralized are preferable from the viewpoint of absorption performance and safety to skin. The equivalent% here is the percentage of neutralized groups among the acid groups.

As the water-absorbent resin (a), its constituent units include unneutralized acid groups such as a carboxyl group, a sulfonic acid group, a sulfuric acid group, a phosphoric acid group and / or an alkali metal salt, an ammonium salt or an amine. Any type of water-absorbent resin having a neutralized group in the side chain as a salt may be used, and the type of (a) and the production method are not particularly limited. Usually, the non-neutralized acid groups in (a) participate in the reaction with the quaternary ammonium carbonate (b).

Preferred examples of the water absorbing resin (a) include a water absorbing resin (a1) having a carboxyl group and / or a salt thereof, a water absorbing resin (a2) having a sulfonic acid group and / or a salt thereof, phosphorus The water-absorbing resin (a3) having an acid group and / or a salt thereof is exemplified, and specific examples thereof are as follows. Examples of the water-absorbent resin (a1) having a carboxyl group and / or a salt thereof include: JP-B-53-46199 and JP-B-53-46200.
And starch-acrylic acid (salt) copolymers described in JP-A-54-30710 and JP-A-56-26909.
And polyacrylic acid salts which have been cross-linked or self-cross-linked by the reversed-phase suspension polymerization method described in JP-A-5-133413, and aqueous polymerization (adiabatic polymerization, pressure polymerization, thin-film polymerization) described in JP-A-55-133413. , Spray polymerization, etc.)
Crosslinked polyacrylic acid (salt) obtained by the method described in JP-A-52-14689 and JP-A-52-27455
Copolymer saponified product of vinyl ester and unsaturated carboxylic acid or derivative thereof described in each of the above publications, cross-linked isobutylene-maleic anhydride copolymer, hydrolyzed product of starch-acrylonitrile copolymer, cross-linked carboxy Examples thereof include a methylcellulose derivative, a crosslinked copolymer of acrylic acid (salt) and acrylamide, a crosslinked acrylamide polymer or a partially hydrolyzed product thereof. The water absorbent resin (a1) may be used in combination of two or more kinds. Further, a surface crosslinked type water absorbent resin in which the surface vicinity of the powder of the water absorbent resin (a1) is further surface crosslinked can be suitably used in the present invention. Known methods can be applied to the surface cross-linking method (type and amount of surface cross-linking agent, cross-linking conditions, etc.).

Specific examples of the water-absorbing resin (a2) having a sulfonic acid group and / or a salt thereof are disclosed in
And cross-linked polyacrylic acid (salt) obtained by copolymerizing a sulfonic acid group-containing monomer described in JP-A-2323 and JP-A-61-36309. Examples of the monomer having a sulfonic acid group used in the water-absorbing resin in which a part of the carboxyl group in the water-absorbing resin is substituted with a sulfonic acid group include:-aliphatic or aromatic vinyl sulfonic acid; [Vinylbenzenesulfonic acid, allylsulfonic acid, vinyltoluenesulfonic acid, styrenesulfonic acid, etc.], ・ (meth) acrylic sulfonic acid [sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate], ・ (meth) Acrylamidosulfonic acid [2-acrylamido-2-methylpropanesulfonic acid] and the like.

Specific examples of the water-absorbent resin (a3) having a phosphate group and / or a salt thereof include a monomer having a phosphate group as a part of the carboxyl group in the above-mentioned crosslinked polyacrylic acid (salt). And a water-absorbing resin substituted by Specific examples of the monomer having a phosphate group include methacryloidoxyethyl phosphate, acryloidoxyethyl phosphate, and the like.

Preferred among (a1) to (a3) are water-absorbent resins (a1) having a carboxyl group and / or a salt thereof, and more preferred are those exhibiting a relatively large absorption capacity, and It is a water-insoluble water-absorbent resin containing acrylic acid and acrylate as main constituent units because of its excellent reactivity when forming a quaternary ammonium salt. If the water-absorbent resin (a1) is used, the water-absorbent resin (A) to be derived has a carboxyl group,
As described above, except for the portion where the carboxyl group is present in the form of a quaternary ammonium salt, an additional effect is obtained in that the remaining carboxyl group adsorbs ammonia, which is a kind of odor component.

Of the carboxyl groups in the water-absorbent resin (a1), those in which 50 to 80 equivalent%, especially 60 to 75 equivalent% are neutralized are preferable, and the neutralized group is 50 equivalent%.
If it is less than 1, the absorption performance decreases and the p of the resin decreases.
H becomes acidic, which is not preferable in terms of safety on the skin. On the other hand, when the content exceeds 80 equivalent%, the effect of adsorbing ammonia and the like becomes poor, and the pH of the obtained antibacterial water-absorbing agent becomes alkaline, which is also not preferable in terms of skin safety.

Examples of the quaternary ammonium carbonate (b) include a compound represented by the following general formula (1) or (2). The compound is reacted with the water-absorbent resin (a). As the water absorbent resin (A), a water absorbent resin having a group represented by the following general formula (3) can be obtained.

[0019]

[0020] [In each formula, R _{1 to} R ₄ are an organic group, R ₅ is a lower alkyl group, and two groups selected from R _{1 to} R ₄ may be mutually bonded to form a ring. In the formula (3), X ^- is an anionic group covalently bonded to a polymer chain in the water absorbent resin (A). ]

The lower alkyl group represented by R ₅ in the formula (2) preferably has 1 to 3 carbon atoms. That is, when the number of carbon atoms is 1 to 3, the compound of the formula (2) reacts with (a) to produce a water-soluble or volatile lower alcohol as a by-product, but does not become an impurity.

In order to obtain an antibacterial water-absorbing resin as (A), in general formula (3), R _{1 to} R ₄ are each an aliphatic hydrocarbon group (however, as described above, two groups are bonded to each other). May form a ring), and at least one of the organic groups represented by R _{1 to} R ₄ is preferably an aliphatic hydrocarbon group having 5 to 20 carbon atoms. As the quaternary ammonium carbonate (b), those in which R _{1 to} R ₄ in the general formula (1) or (2) are in the same range must be used.

The quaternary ammonium carbonate (b) has, for example, at least one aliphatic alkyl group having 5 to 20 carbon atoms.
Tertiary amine (b1) and carbonic acid diester (b2)
This reaction yields a compound of the general formula (1) or (2) or a mixture of both compounds, which can be used in the method of the present invention.

Specific examples of (b1) include octyldimethylamine, decyldimethylamine, lauryldimethylamine, myricetyldimethylamine, cetyldimethylamine, stearyldimethylamine, dihexylmethylamine, dioctylmethylamine, didecylmethylamine, Didodecylmethylamine, 2-heptadecenyl-hydroxyethylimidazoline and the like can be mentioned. Preferred are tertiary amines having two aliphatic alkyl groups having 5 to 20 carbon atoms, and more preferred are dioctylmethylamine and didecylmethylamine. (B
Examples of 2) include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate and the like, and dimethyl carbonate having a small number of carbon atoms in the alkyl group is preferred because of its excellent reactivity.

The molar ratio of the tertiary amine (b1) to the carbonic acid diester (b2) during the production of the quaternary ammonium carbonate compound (b) is usually 1: (0.3-4.0), preferably 1: (0.5 to 2.5), and the reaction temperature is usually 30 to 150 ° C, preferably 50 to 120 ° C.
If necessary, a solvent such as methanol or ethanol, or a mixed solvent of these with water can be used.

The ratio of the water-absorbent resin (a) to the quaternary ammonium carbonate (b) in producing the water-absorbent resin (A) depends on the amount of the quaternary ammonium introduced into the resin. When an antibacterial water-absorbing resin is obtained, various changes can be made depending on the balance between the desired absorption performance and antibacterial performance. When obtaining an antibacterial water-absorbing resin, usually (a):
The ratio of (b) is 1: (3 × 10 ^{−5 to} 0.3), preferably 1: (1 ×), based on the equivalent ratio of the unneutralized acid group in (a) and (b). 10 ^{−4 to} 0.1), and more preferably 1: (3 × 10 ⁻⁴ to 8 × 10 ⁻² ). If the equivalent ratio of (b) is less than 3 × 10 ⁻⁵ , the resulting resin will have poor antibacterial effect. On the other hand, when the equivalent ratio of (b) is 0.3, a sufficient antibacterial effect is exhibited, and even if the equivalent ratio is further increased, the antibacterial effect hardly increases, so that it is unnecessary.

The method of the present invention is characterized in that (a) and (b) are reacted in the presence of water to obtain the water-absorbent resin (A). The acid group of
The reaction proceeds as a counter-anion of the quaternary ammonium cation in (b), and the carbonate anion is vaporized as carbon dioxide gas by the reaction, so that a resin (A) having high purity without residual by-products can be obtained. There are advantages. When (b) is a compound of the general formula (2), lower alcohols are generated together with carbon dioxide gas. However, the resin (A) is dissolved in water or vaporized, so that there is no by-product remaining and high purity resin (A) Is obtained. Note that the above reaction does not necessarily mean that 100% of the reaction is carried out, and practically, unreacted (b) may remain to some extent together with (A). That is, the state in which a salt is formed as a quaternary ammonium cation,
The state of the quaternary ammonium carbonate may coexist.
When reacting (a) and (b), a crosslinking agent having two or more functional groups reactive with an acid group of (a) can be further crosslinked by coexisting with (b).

More specific embodiments of the method of the present invention include, for example, the following methods (1) to (4).
The methods (1) and (4) are preferred. (1) After mixing the aqueous liquid of the quaternary ammonium carbonate (b) with the powder of the water-absorbent resin (a), the mixture is reacted to form a quaternary ammonium salt near the surface of the powder of the water-absorbent resin. Method. (2) A method in which (b) is kneaded with the hydrogel polymer obtained in the production process of (a), and the mixture is heated, reacted, dried, and pulverized. (3) After absorbing water in (a) to create a water-absorbing gel,
A method in which (b) is kneaded, heated to react, dried and pulverized. (4) A method in which a water-containing gel is prepared by absorbing the aqueous solution of (b) into (a), kneaded, heated, reacted, dried, and pulverized.

The amount of water used in the methods (1) to (4) is usually 1 to 500 parts by mass, preferably 5 to 450 parts by mass, per 100 parts by mass of (a). If the amount of water is less than 1 part by mass, the reaction between (a) and (b) does not proceed sufficiently, while if it exceeds 500 parts by mass, there is no problem in the reaction between (a) and (b). However, a large amount of water must be subsequently evaporated, which is not economical.

In the above methods (1) to (4),
The industrial apparatus for mixing (a) and (b) is not particularly limited, and a conventionally known apparatus can be used. For example, as an industrial device for mixing the powder of (a) and the aqueous solution of (b), a universal mixer, a turbulizer, a Nauta-type mixer, a ribbon blender, a conical blender, V
Examples include a mold mixer, a screw mixer, a fluidized bed mixer, a spray mixer, and a mortar mixer.
Industrial equipment for kneading (b) with the hydrogel or the water-absorbing gel of (a) includes, for example, a kneader, a single-screw or twin-screw extrusion mixer, a universal mixer, a gear compounder, a minch machine, a Nauter-type mixer. And a screw-type mixer.

The temperature at which (a) and (b) are reacted is not particularly limited, but the following methods can be exemplified. As in the method (1), when (a) at the time of the reaction is in the form of a powder, the temperature is preferably from 1 to 150 ° C, particularly from 10 to 150 ° C.
130 ° C. As in the above methods (2) to (4), when (a) at the time of the reaction is a hydrogel and needs to be dried together with the reaction, the temperature is preferably 40 to 150 ° C, particularly 40 to 130 ° C. . If necessary, the reaction and drying can be performed under reduced pressure. If the temperature is 0 ° C. or lower, water solidification occurs, which is not preferable. On the other hand, if the temperature exceeds 150 ° C., decomposition may occur depending on the type of (b), which is not preferable.

Although the water-absorbent resin (A) is obtained by the method of the present invention, the content of the quaternary ammonium base in (A) can be varied depending on the purpose as described above. For example, the content of the quaternary ammonium base in (A) when the antibacterial water-absorbing resin is intended is usually 2 × 10 4 in terms of the content of the quaternary nitrogen atom with respect to the mass of the resin. ^{-4 to} 0.8% by mass, preferably 1 × 10 ^-3 to
It is 0.4% by mass, especially 2 × 10 ^{−3 to} 0.1% by mass.

The resulting water-absorbent resin (A) is preferably pulverized into a powder, for example, in the form of granules, granules, granules, flakes, lumps, pearls, fine powders, etc. Any shape may be used. Particularly preferred are granules, granules, granules, flakes and lumps. There is no particular limitation on the particle size or particle size distribution of the powdered product, but preferably 90% by weight or more is 1 mm or less, and more preferably 90% by weight or more is 0.1 to 0.1%.
0.9 mm, especially 95% by weight or more is 0.1 to 0.9 mm
It is.

The water-absorbing resin (A) thus obtained has an absorption capacity for physiological saline (0.9% aqueous sodium chloride solution) of preferably 30 g / g or more, more preferably 35 g / g or more.
-80 g / g, particularly preferably 40-75 g / g. In order for the water-absorbing resin (A) to have this water-absorbing performance, the water-absorbing performance when the raw water-absorbing resin (a) has the same powder shape, particle size, and particle size distribution as (A) is as follows:
What is equal to or exceeds (A) may be used. In addition, absorptivity is measured by the method mentioned later.

The water-absorbing resin containing a quaternary ammonium base obtained by the method of the present invention can be applied to various absorbent articles, and if a water-absorbing resin having antibacterial performance is produced, the water-absorbing effect and the antibacterial effect can be improved. An absorbent article excellent in both is obtained. As a method of applying the quaternary ammonium base-containing water-absorbing resin to the absorbent article, a layer in which the water-absorbing resin is held in a water-absorbing support may be formed, for example, pulp arranged in layers, A method of dispersing particles between layers of fibrous materials such as heat-fusible fibers or a mixture thereof, a method of mixing with fibrous materials such as pulp and / or heat-fusible fibers, two or more sheets of water-absorbing paper, For example, a method of sandwiching with a nonwoven fabric may be used.

The quaternary ammonium salt group-containing water-absorbent resin obtained by the method of the present invention has good powder fluidity and has the same handling aptitude as conventional water-absorbent resins. Absorbent articles can be manufactured with this equipment. The amount of the water-absorbing resin added to the absorbent article can be variously changed according to the type and size of the absorbent article and the target absorption performance. For example, when the absorbent article is a disposable diaper, an incontinence pad, a surgical underpad, a mat for postpartum, etc., the amount of addition is usually 3 to 20 g / sheet,
When the absorbent article is a sanitary napkin, a panty liner, a breast milk pad, a dressing for protecting a wound surface, etc., the amount is usually 0.2 to 3 g / piece. When applied to two or more sheets of water-absorbing paper or a sheet sandwiched with non-woven fabric, usually 1
About 0 to 80 g / m ² is appropriate.

[0037]

The present invention will be further described with reference to the following examples and comparative examples, but the present invention is not limited to these examples. The absorption amount of the antibacterial water-absorbent resin itself, the antibacterial effect, and the effect confirmation test of the absorbent article using the antibacterial water-absorbent resin were measured by the following methods. Hereinafter, unless otherwise specified,% indicates mass%.

(1) Absorption: 1.0 g of a sample was placed in a 250 mesh nylon net tea bag, immersed in excess physiological saline (0.90% saline) for 1 hour, and absorbed. 15 by lifting and hanging vertically
Drain for a minute and measure the weight gain. This increased weight was taken as the absorption amount.

(2) Powder flowability: The powder flowability was evaluated by measuring the angle of repose. The angle of repose was measured using a powder tester (manufactured by Hosokawa Micron Corporation), and a suitable amount of a water-absorbent resin sample was gently put into a sieve (opening: 710 μm). Drain the tip of the attached glass funnel onto the attached disc. When the ridge line of the deposited powder reaches a certain angle, the outflow of the water-absorbing resin is stopped, and the protractor is moved so that the linear portion of the protractor is parallel to the ridge line of the deposited powder, and the angle of repose is obtained. The larger the angle of repose, the poorer the powder fluidity.

(3) Antibacterial test of the water-absorbing resin:
After dissolving 3.45 g of the sensitive bouillon medium and 150 ml of water in a 300 cc flask and dissolving, the mixture is sterilized in an autoclave. After adding 1.0 g of a test sample to this medium and swelling while stirring, Escherichia coli was inoculated so that the initial strain number was 1 × 10 ⁶ cells / ml. This sample is cultured with shaking at 37 ° C., sampled after 2 hours and 10 hours, and if necessary, serially diluted with sterile saline.
Place this sampled or diluted product in a sterile petri dish 1m
After adding 1 l each, 20 ml of an agar medium is poured, uniformly dispersed and solidified on a Petri dish, and cultured at 37 ° C. for 2 days. After culturing, colonies are counted, and the dilution ratio is multiplied to obtain the number of viable strains. The measurement of the number of viable bacterial strains is performed by a mixed flat culture method. On the other hand, the number of viable strains when only Escherichia coli was inoculated without adding a sample as a blank was 5 × 10 ⁸ cells / ml after 2 hours and 6 × 10 ⁹ cells / ml after 10 hours. Similarly, the antibacterial properties of the ammonia-producing bacteria were tested. In this case, ammonia-producing bacteria were inoculated so that the initial number of strains was 1 × 10 ⁷ cells / ml. On the other hand, the number of viable strains in the case of inoculating only ammonia-producing bacteria without adding a sample as a blank was 8 × 10 ⁷ cells / ml after 2 hours,
After 10 hours, the concentration was 4 × 10 ⁹ cells / ml.

(4) Test for confirming the effect of the absorbent article to which the antibacterial water-absorbing resin is applied: Preparation of the absorbent article: A polyethylene sheet cut into a rectangle of 14 cm × 35 cm, tissue paper of the same size and basis weight Overlay a 100 g / m ² fluff pulp layer. Next, 2.94 g of the sample is evenly spread on the fluff pulp, and a fluff pulp layer having a basis weight of 100 g / m ^2, a tissue paper and a nonwoven fabric are laminated in this order.
This laminate is pressed at a pressure of 5 kg / cm ² for 90 seconds to produce a model paper diaper.

-Odor prevention effect test: 80 ml of fresh urine was added to the center of a model disposable diaper to which an antibacterial water-absorbing resin was applied, absorbed, placed in a 5 liter wide-mouth bottle, and sealed. This is stored in a thermostat set at 40 ° C. for 10 hours. Thereafter, the lid of the wide-mouth bottle is opened in an odorless room to smell the odor, and the odor intensity is evaluated in the following six steps. Evaluation is 10 with odor determination ability confirmed by T & T Olfactometer method
Conducted by human panelists and averaged. 0: No odor 1: Smell that can be detected at last (perceived odor value density) 2: Weak odor that can tell what odor is (cognitive odor value density) 3: Odor that can be easily detected 4: Strong odor 5: Strong odor

(5) Absorbent article performance test: Absorbance: A model paper diaper was placed in a large excess saline solution.
Immerse for 0 minutes, then put on a wire net, apply a load of 10 kg, drain for 20 minutes, measure the increased weight and determine the amount of absorption. -Rewetting amount: 50 ml of artificial urine is poured into the center of the model paper diaper. 10 minutes later, 10cm ×
2. Place 10 pieces of 10 cm filter paper on top of each other and
Apply a load of 5 kg evenly. After 3 minutes, the increased weight of the filter paper is measured, and this value is defined as the re-wet amount. The smaller the amount of rewetting, the better the dryness of the model diaper.

EXAMPLE 1 76.6 g of sodium acrylate, 23 g of acrylic acid, 0.4 g of N, N'-methylenebisacrylamide and 295 g of deionized water were placed in a 1-liter glass reaction vessel.
And the temperature of the contents was kept at 5 ° C. while stirring and mixing. After flowing nitrogen into the contents to reduce the amount of dissolved oxygen to 1 ppm or less, 1 g of a 1% aqueous solution of hydrogen peroxide, 1.2 g of a 0.2% aqueous solution of ascorbic acid and 2,2′-azobisamidinopropane dihydro The polymerization was started by adding 2.4 g of a 2% aqueous solution of chloride, and the polymerization was carried out for about 5 hours to obtain a hydrogel polymer (1) having a water-absorbing resin concentration of 25%. While kneading 400 parts of this hydrogel polymer (1) with a kneader, a 30% methanol / water mixed solution of didecyldimethylammonium carbonate (methanol /
(Water ratio = 50/50% by mass) and kneaded uniformly. The kneaded product was dried at 90 ° C. under reduced pressure, pulverized with a pin mill, and adjusted in particle size so that the particle size of 850 to 150 μm was about 95% to obtain an antibacterial water absorbent resin. Tables 1 and 2 show the performance measurement results of the antibacterial water-absorbent resin (A1).

Example 2 In Example 1, a 30% methanol / water mixed solution of didodecyldimethylammonium carbonate was used in the same amount instead of a 30% methanol / water mixed solution of didecyldimethylammonium carbonate. An antibacterial water-absorbent resin (A2) was obtained in the same manner as in Example 1. Tables 1 and 2 show the performance measurement results of the antibacterial water-absorbent resin (A2).

Example 3 100 parts of a commercially available water-absorbent resin ("Sunwet IM-1000" manufactured by Sanyo Chemical Industries; crosslinked product of starch-sodium acrylate copolymer; degree of neutralization: 70 mol%)
A portion was absorbed to obtain a hydrogel product. 3 parts of the same didecyldimethylammonium carbonate (30% methanol solution) as in Example 1 was added to the hydrogel, and the mixture was uniformly kneaded with a kneader, followed by drying, pulverization and particle size adjustment in the same manner as in Example 1. Thus, an antibacterial water-absorbing resin (A3) was obtained. Tables 1 and 2 show the performance measurement results of the antibacterial water-absorbent resin (A3).

Example 4 Commercially available water-absorbent resin (“Sunwet IM-5800” manufactured by Sanyo Chemical Industries, a surface-crosslinked type water-absorbent resin obtained by surface-crosslinking 72 mol% neutralized sodium salt of crosslinked polyacrylic acid) 10
While stirring 0 parts at high speed with a household mixer, 4.5 parts of a 20% methanol / water mixed solution of didecyldimethylammonium carbonate (methanol / water ratio = 50/50% by mass) was added little by little to make the mixture uniform. The mixture was mixed to obtain an antibacterial water-absorbent resin (A4). The mixing temperature at this time was 24 ° C.
Tables 1 and 2 show the performance measurement results of the antibacterial water-absorbent resin (A4).

Example 5 The procedure of Example 4 was repeated except that the same amount of a 20% methanol / water mixed solution of octyltrimethylammonium carbonate was used instead of the 20% methanol / water mixed solution of didecyldimethylammonium carbonate. An antibacterial water-absorbent resin (A5) was obtained in the same manner as in Example 4. Tables 1 and 2 show the performance measurement results of the antibacterial water-absorbent resin (A5).

Examples 6 and 7 In Example 4, the amount of didecyldimethylammonium carbonate (20% methanol / water mixed solution) was changed to 0.4.
Antibacterial water-absorbing resin (A6) in the same manner as in Example 4 except that 5 parts (Example 6) or 9 parts (Example 7) is used.
And (A7) were obtained. The performance measurement results of these antibacterial water-absorbing resins are shown in Tables 1 and 2.

Test Example The antibacterial water-absorbing resin obtained in Example 1 and Examples 3 to 7 was uniformly applied at a rate of 60 g / m ² between two layers of pulp having a basis weight of 100 g / m ^2. And sandwich it,
Pressing was performed at a pressure of 5 kg / cm ² . After laminating a polyethylene film on the lower layer and a polypropylene non-woven fabric on the upper layer, an absorbent article was prepared by cutting the film to a size of 14 cm (width) × 35 cm (length). Absorbent articles (a), (b), (c), (d) obtained using the antibacterial water-absorbing resins (A1) and (A3) to (A7) obtained in Examples 1 and 3 to 7. ), (E) and (f)
Table 3 shows the results of the performance measurements.

Comparative Example 1 The hydrogel polymer (1) obtained in Example 1 was dried at 90 ° C. under reduced pressure and pulverized with a pin mill, and then the particle size was adjusted so that the particle size of 850 to 150 μm became about 95%. Thus, a comparative water-absorbent resin powder was obtained. Tables 1 and 2 show the performance measurement results.

Comparative Examples 2 and 3 Tables 1 and 2 show the performance measurement results of "Sunwet IM-1000" and "Sunwet IM-5800" as Comparative Examples 2 and 3, respectively.

Comparative Example 4 In Example 4, a 20% aqueous solution of benzalkonium chloride was stirred while 100 parts of a commercially available water-absorbent resin (manufactured by Sanyo Chemical Industries, “Sunwet IM-5800”) was stirred at high speed with a household mixer. 4.5 parts were added and mixed uniformly to obtain an antibacterial water-absorbent resin composition. Tables 1 and 2 show the performance measurement results of this composition.

Comparative Example 5 In Example 4, 100 parts of a commercially available water-absorbent resin (manufactured by Sanyo Kasei Kogyo Co., Ltd., “Sunwet IM-5800”) was stirred at a high speed with a household mixer while 20% methanol of cetyltrimethylammonium chloride was added. 4.5 parts of a water / water mixed solution (methanol / water ratio = 50/50% by mass) were added and uniformly mixed to obtain a comparative antibacterial water-absorbent resin composition. Tables 1 and 2 show the performance measurement results of this composition.
Shown in

Comparative Test Examples Absorbent articles (g), (B) were prepared using the water-absorbent resin particles or the antibacterial water-absorbent resin compositions of Comparative Examples 1 to 5 in the same manner as described in the test examples. h), (i), (j) and (k) were obtained. Table 3 shows the performance measurement results of the absorbent articles of these comparative test examples.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

The method of the present invention has the following features and effects. According to the method of the present invention, it has become possible to produce a water-absorbent resin having a quaternary ammonium base introduced into a side chain. In the method of the present invention, unless unreacted raw materials remain,
An extremely high purity quaternary ammonium base-containing water-absorbent resin can be obtained without by-products remaining with the resin.
Even if the quaternary ammonium carbonate remains as an unreacted raw material, there is no problem in practical use as a water-absorbing resin such as water absorption performance and safety to the skin. Rather, the antibacterial performance of the quaternary ammonium carbonate can be expected. The method of the present invention is extremely suitable as a method for producing a water-absorbing resin having both an excellent absorption function and an antibacterial property against microorganisms such as Escherichia coli and ammonia-producing bacteria. The obtained resin is particularly excellent in antibacterial action against ammonia-producing bacteria, so that generation of ammonia odor is suppressed. In a simple mixture of a conventional water-absorbent resin and an antibacterial component or a deodorant component, the two may be separated by vibration or impact, or when applied to an absorbent article, the water-absorbent resin and the antibacterial component or Although there was a concern that the deodorant component and ubiquity would occur, the method of the present invention allowed the water-absorbent resin to react and fix the antibacterial agent component with the water-absorbent resin, so there was no fear of separation or uneven distribution, In addition, unlike the conventional antibacterial water-absorbent resin composition, there is no deterioration in powder characteristics (powder fluidity, dust generation, etc.). By applying the obtained quaternary ammonium base-containing water-absorbent resin to absorbent articles such as disposable diapers and sanitary articles, it is possible to impart an antibacterial function to the absorbent articles, thereby suppressing the generation of offensive odors, The occurrence of rash is reduced, and the performance of the absorbent article is also good.

Because of the above effects, the method of the present invention can be applied to various types of paper diapers for adults and children, incontinent pads, sanitary napkins, panty liners, breast milk pads, puerperal mats, medical underpads, etc. It is particularly useful as a method for producing a quaternary ammonium base-containing water-absorbent resin applicable to absorbent articles. Further, the present invention is useful as a method for producing a quaternary ammonium base-containing water-absorbing resin applicable to a gelling agent or an excrement treating agent for various body fluids that generate an odor due to putrefaction such as pet urine and waste blood. It is also useful when producing sheet-like or tape-like absorbent articles such as pet urine absorbent sheets and drip absorbents. In addition, it is also used for applications that use a gel made of water-absorbent resin with water absorption (for example, cold insulators, artificial snow, water beds, etc.), and for applications that generate odor due to decay, such as sludge solidifying agents and anti-condensation wall materials. It is useful as a method for producing a quaternary ammonium base-containing water-absorbent resin that can be applied.

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Kunihiko Sato (56) References JP-A-58-143749 (JP, A) JP-A-54-86584 (JP, A) JP-A-2-124905 (JP, A) 58-13749 (JP, A) JP-A 5-88475 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 8/44

Claims (10)

(57) [Claims] A quaternary ammonium carbonate (b) is reacted with a powder or a hydrogel of a water-absorbent resin (a) having an acid group on a side chain in the presence of water to form an acid group on the side chain. A method for producing a quaternary ammonium salt group-containing water-absorbent resin, which comprises obtaining a water-absorbent resin (A) at least partially present in the form of a quaternary ammonium salt. 2. The water-absorbent resin (a) having an acid group of 50 to 80.
The method according to claim 1, wherein the equivalent% is an alkali metal salt. 3. A compound represented by the following general formula (1) or (2) is used as the quaternary ammonium carbonate (b), and a water absorbing resin (A) is represented by the following general formula (3). 3. The method according to claim 1, wherein a water-absorbing resin having a group is obtained. ^{_{R 2 | [R 1 -N +}} -R 3] 2 · CO 3 2- (1) | R 4 R 2 | [R 1 -N + -R 3] · R 5 CO 3 - (2) | R 4 ^{_{R 2 | -X - · [R}} 1 -N + -R 3] (3) | R 4 [ in each formula, R ₁ to R ₄ is an organic group, R ₅ is a lower alkyl group, R ₁ to R Two groups selected from ₄ may be mutually bonded to form a ring. In the formula (3), X ^- is an anionic group covalently bonded to a polymer chain in the water absorbent resin (A). ] 4. In the general formulas (1) and (2), R ₁ , R ₂ , R
₃ , R ₄ are aliphatic hydrocarbon groups, and R ₁ , R ₂ , R ₃ , R ₄
4. The method according to claim 3, wherein at least one of the organic groups is an aliphatic hydrocarbon group having 5 to 20 carbon atoms. 5. A method according to claim 1, wherein the equivalent ratio of the unneutralized acid group in (a) to (b) is 1: (3 × 10 ^{−5 to} 0.3).
The method according to any one of claims 1 to 4, wherein the reaction is carried out at a ratio of: 6. The powder of the water-absorbent resin (a) and the aqueous solution of the quaternary ammonium carbonate (b) are mixed, and the vicinity of the surface of the powder of (a) is reacted with (b). The method according to any one of the above. 7. A mixture obtained by kneading a quaternary ammonium salt (b) with a water-containing gel of a water-absorbent resin (a) using a kneader,
The method according to any one of claims 1 to 5, wherein (b) is reacted to the inside of the particles of (a) by drying and reacting. 8. The water-absorbent resin (A) having a quaternary nitrogen atom content of 2 × 10 ^{−4 to} 0.8% by mass and having an antibacterial property. The method according to any one of the above. 9. A water-absorbing material having an absorbency of 30 g / g or more for physiological saline produced by the method according to claim 1. 10. An absorbent article comprising the water-absorbing material according to claim 9.