JP5436737B2 - Aqueous solution absorbent material and hygiene products - Google Patents

Description

  The present invention comprises three components (A) a polymer of an acrylamide compound, (B) a water-swellable clay mineral that can be uniformly dispersed in water, and (C) water as constituents, and (A) and ( The organic-inorganic composite polyacrylamide-based aqueous gel in which (C) is included in the three-dimensional network composed of B) and / or an aqueous solution-absorbing material comprising a dried product thereof as a constituent component. The aqueous solution-absorbing material comprising the organic / inorganic composite polyacrylamide-based aqueous gel and / or dried product thereof as constituents of the present invention has a higher gel strength and aqueous solution-absorbing capacity than conventional ones, and sanitary products such as sanitary products and disposable diapers. It is useful as an absorbent material for other aqueous solutions.

  In sanitary products that absorb sanitary products, paper diapers, or other water-soluble body fluids, water-absorbing resins are often used as liquid-absorbing materials that replace conventional pulp and water-absorbing paper as constituent materials. Examples of such a water-absorbing resin include a hydrolyzate of starch-acrylonitrile graft polymer (Japanese Patent Publication No. 49-43395), an acrylonitrile copolymer or an acrylamide copolymer hydrolyzate (Japanese Patent Publication No. 53-15959). In addition, polyacrylic acid cross-linked products, acrylamide copolymer cross-linked hydrolysates, and cross-linked isobutylene-maleic anhydride copolymer neutralized products are known.

  Such a water-absorbing resin is generally a water-soluble resin that has been slightly crosslinked to render it water-insoluble. As the crosslinking method, a method of adding an organic crosslinking agent at the time of polymerization of the hydrophilic monomer and crosslinking at the same time as the polymerization, a method of causing a water-soluble polymer and an organic crosslinking agent to react to crosslink between molecules, and the like are known. Yes.

  The water-absorbing resins obtained by these cross-linking methods use as little cross-linking agent as possible in order to increase the absorption capacity, but due to this, these water-absorbing resins have low gel strength and absorb capacity under pressure. However, it has a drawback that it is easy to form a so-called gel block.

  Furthermore, a water-soluble component coexists in the water-absorbent resin, which causes a decrease in absorption rate and a decrease in stability of the water-absorbing gel due to elution of the water-soluble component after absorption. On the other hand, when the amount of the crosslinking agent used is increased to increase the crosslinking density, if the entire crosslinking is carried out at a high density, the absorption ability, which is the basic performance of the water-absorbent resin, is not preferable.

  As a method for solving these problems, a method of crosslinking the particle surface of the powdery water-absorbing polymer with a crosslinking agent (JP-B-60-18690, JP-B-61-48521), water-absorbing resin particles (Japanese Patent Publication No. 6-39487, Japanese Patent Publication No. 6-74331, USP 5,314,420 publication), and a method using trimethylolpropane triacrylate as a crosslinking agent (WO94 / 20547 publication) ) Etc. are being studied. However, there has been a demand for the development of absorbent hygiene materials having higher gel strength and absorption capacity, mainly for adult hygiene products that are subject to large pressures and large throughput.

Problems to be solved by the present invention

  The problem to be solved by the present invention is an aqueous solution absorbent material having higher gel strength and absorption capacity than conventional hygiene products, sanitary products such as disposable diapers, and other aqueous solution absorbent materials, and hygiene using the same To provide supplies.

Means for solving the problem

  As a result of diligent research to solve the above problems, the present inventors have obtained an organic / inorganic composite polyacrylamide aqueous gel obtained by polymerizing an acrylamide compound in the presence of water and water-swellable clay, and / or Or it discovered that the dry body became the outstanding aqueous solution absorption material which solved the said problem, and came to complete this invention.

  That is, the present invention includes three components as components (A) a polymer of an acrylamide compound, (B) a water-swellable clay mineral that can be uniformly dispersed in water, and (C) water. And (B) is an aqueous / absorbent material comprising an organic / inorganic composite polyacrylamide-based aqueous gel in which (C) is included and / or a dried product thereof as a constituent component.

  The present invention also provides an organic / inorganic composite polyacrylamide aqueous solution obtained by polymerizing (A) an acrylamide compound in the presence of (B) a water-swellable clay mineral that can be uniformly dispersed in water and (C) water. An aqueous solution-absorbing material comprising gel and / or a dried product thereof as a constituent component.

  More specifically, the aqueous solution absorbing material of the present invention has a water-swellable clay mineral / acrylamide compound polymer weight ratio of 0.01 which constitutes an organic / inorganic composite polyacrylamide aqueous gel and can be uniformly dispersed in water. -10, aqueous solution absorbing material in which water-swellable clay mineral that can be uniformly dispersed in water is water-swellable smectite, and organic / inorganic composite polyacrylamide-based aqueous gel at the time of equilibrium swelling at 20 ° C. The aqueous solution absorbing material is characterized in that the weight of the aqueous solution is 20 times or more of the dry body weight.

  In the present invention, an organic / inorganic composite polyacrylamide-based aqueous gel (diameter: 5.5 mm, length: 30 mm) containing 10 times the amount (weight ratio) of the polymer of the acrylamide compound is 1 in the thickness direction. An organic / inorganic composite polymer containing an aqueous solution absorbing material characterized by its shape not being destroyed even when compressed to a thickness of / 3 or less, and water 10 times the weight (weight ratio) of a polymer of an acrylamide compound. It contains an aqueous solution absorbing material characterized in that even when an acrylamide-based aqueous gel (diameter: 5.5 mm, length: 30 mm) is stretched to a length of 2 times or more in the length direction, its shape is not destroyed.

  Furthermore, the present invention provides an organic / inorganic composite polyacrylamide-based aqueous gel (diameter: 5.5 mm, length: 30 mm) containing 10 times the amount (weight ratio) of the polymer of the acrylamide compound. In other words, the present invention includes an aqueous solution absorbing material characterized in that its shape is not broken even if it is bent and deformed to an angle of 100 degrees or more, and a hygiene product using these aqueous solution absorbing materials.

  The present invention comprises three components (A) a polymer of an acrylamide compound, (B) a water-swellable clay mineral that can be uniformly dispersed in water, and (C) water as constituents, and (A) and ( An organic-inorganic composite polyacrylamide-based aqueous gel in which (C) is included in the three-dimensional network consisting of B) and / or an aqueous solution-absorbing material comprising a dried product thereof and a sanitary article using the same .

  Examples of (A) acrylamide compounds used in the present invention include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-cyclopropylacrylamide, N-isopropylacrylamide, methacrylamide, N-methylmethacrylamide, N -Cyclopropylmethacrylamide, N-isopropylmethacrylamide, N, N-dimethylacrylamide, N-methyl-N-ethylacrylamide,

N-methyl-N-isopropylacrylamide, N-methyl-Nn-propylacrylamide, N, N-diethylacrylamide, N- (hydroxymethyl) acrylamide, diacetone acrylamide, N-acryloylpyrrolidine, N-acryloylpiperi Examples thereof include din, N-acryloylmethyl homopiperazine, N-acryloylmethylpiperazine and the like. These compounds can be used alone or in combination of two or more.

  (B) The water-swellable clay mineral that can be uniformly dispersed in water as used in the present invention is a clay mineral that is finely and uniformly dispersible in water and has a property of dissolving or swelling in water. In particular, it is preferably a layered clay mineral that can be uniformly dispersed in water at a molecular (single layer) or close to that level. For example, water-swellable smectite or water-swellable mica is used. Specific examples include water-swellable hectorite containing sodium as an interlayer ion, water-swellable montmorillonite, water-swellable saponite, and water-swellable synthetic mica.

  In the present invention, the water-swellable clay is particularly preferably dissolved in water. Here, dissolution means a state in which there is no large clay mineral aggregate that causes precipitation of a clay mineral or a cloudy aqueous solution. More preferably, it is dispersed at a nanometer level (thickness) of about 1 to 10 layers, and particularly preferably is dispersed at a thickness of about 1 or 2 layers.

  The ratio of the polyacrylamide and the clay mineral contained in the organic / inorganic composite polyacrylamide-based aqueous gel and / or the dried product thereof used in the present invention is only required to satisfy the above properties, and the acrylamide compound and the water-swellable clay mineral used. The weight ratio of clay mineral / polyacrylamide is preferably 0.01 to 10, more preferably 0.03 to 2.0, and particularly preferably 0.05 to 1.0. .

  If the clay mineral / polyacrylamide weight ratio is less than 0.01, the aqueous gel targeted by the present invention cannot be obtained. If the clay mineral / polyacrylamide weight ratio exceeds 10, the aqueous gel is brittle, or a large amount of water is used in production. Will arise.

  The organic / inorganic composite polyacrylamide-based aqueous gel used in the present invention comprises (A) a polymer of an acrylamide compound, (B) a water-swellable clay mineral that can be uniformly dispersed in water, and (C) water. A component is included as a constituent component, and (C) is included in a three-dimensional network composed of (A) and (B). This organic / inorganic composite polyacrylamide-based aqueous gel is an aqueous gel obtained by radical polymerization of an acrylamide-based compound in the presence of water-swellable clay finely dispersed in water. 1 or 2 layers or 1 to 10 layers It is presumed that the clay mineral dispersed at the nanometer level has a structure in which the acrylamide polymer and the clay mineral are uniformly combined in a water swollen state, acting as a crosslinking agent for the acrylamide compound.

  The radical polymerization reaction can be performed by a known method such as the presence of peroxide and / or ultraviolet irradiation in the absence of molecular oxygen. Furthermore, this polymerization reaction can be accelerated by heating or ultraviolet irradiation. The initiator and catalyst for radical polymerization can be used by appropriately selecting from known and commonly used radical polymerization initiators and catalysts.

  Specifically, as a polymerization initiator, a water-soluble peroxide such as potassium peroxodisulfate or ammonium peroxodisulfate, a water-soluble azo compound (eg, VA-044, V-50, manufactured by Wako Pure Chemical Industries, Ltd.) ) Etc. are used. As the catalyst, N, N, N ′, N′-tetramethylethylenediamine, β-dimethylaminopropionitrile, or the like is used. The polymerization temperature can be set in the range of 0 ° C. to 100 ° C. according to the type of polymerization catalyst and initiator. The polymerization time varies depending on the catalyst, the initiator, and the polymerization temperature, but can generally be carried out in the range of several tens of seconds to several hours.

It is also possible to prepare a polyacrylamide-based aqueous gel in the form of fine particles by coexisting a known surfactant in the radical polymerization reaction.
The aqueous solution-absorbing material of the present invention comprises an organic-inorganic composite polyacrylamide-based aqueous gel obtained by polymerizing an acrylamide compound in the presence of water-swellable clay and water and / or a dried product thereof, and an organic crosslinking agent However, depending on the application, an organic crosslinking agent may be included together with the above components.

  The concentration of the organic crosslinking agent contained is not particularly limited and can be selected according to the purpose. As these organic crosslinking agents, conventionally known N, N′-methylenebisacrylamide, N, N′-propylenebisacrylamide, di (acrylamidomethyl) ether, 1,2-diacrylamide ethylene glycol, 1,3- Bifunctional compounds such as diacryloylethyleneurea, ethylene diacrylate, N, N′-diallyl tartaramide, N, N′-bisacrylylcystamine, and trifunctional compounds such as triallyl cyanurate and triallyl isocyanurate Examples are sex compounds.

  The organic / inorganic composite polyacrylamide-based aqueous gel and / or the dried product thereof used in the present invention has a characteristic that the yield in polymerization is high and there are almost no water-soluble components inside the aqueous gel. This is confirmed by the high polymerization yield after washing with water. This result is presumed to be due to the finely dispersed clay layer acting as an effective cross-linking agent in the polymerization of acrylamide compounds in the presence of water-swellable clay minerals. Thus, a small amount of water-soluble components in the aqueous gel is effective in improving the safety, stability, dry feeling and the like of the absorbent material.

  In the aqueous solution absorbing material of the present invention, an organic / inorganic composite polyacrylamide-based aqueous gel and / or a dried product thereof is used as a constituent. That is, a dry body substantially free of water or an aqueous gel containing water below equilibrium swelling is selected and used depending on the purpose. It is also possible to use a combination of dry bodies and aqueous gels having different moisture contents.

  Organic / inorganic composite polyacrylamide-based aqueous gel and / or dried product thereof is processed during or after polymerization so as to have a shape and size suitable as an aqueous solution absorbent material used in sanitary products such as sanitary products and disposable diapers. Used. For example, since the water absorption rate depends on the shape and size of the gel or the dried body, it is effective to make it as small as possible and increase the surface area in order to increase the absorption rate. For example, in the radical polymerization reaction, a known surfactant is further allowed to coexist to prepare a polyacrylamide aqueous gel in the form of micron-order fine particles.

  The organic / inorganic composite polyacrylamide-based aqueous gel and / or dried product thereof used in the present invention is characterized by a high water absorption rate relative to the weight of the dried product. In general, when the water absorption is increased, the gel strength is lowered. However, the organic / inorganic composite polyacrylamide aqueous gel in the present invention has a higher water absorption than the aqueous gel obtained using a conventional organic crosslinking agent. Has high gel strength.

  The water absorption rate of the organic / inorganic composite polyacrylamide-based aqueous gel used in the present invention is usually 20 times or more, more preferably 30 times or more, and particularly preferably 40 times the dry weight when it is equilibratedly swollen in water at 20 ° C. Absorbs the above water or aqueous solution.

  Having a high water absorption rate can prevent liquid leakage during use of the aqueous solution absorbent material, reduce the amount of the aqueous solution absorbent material used in sanitary goods, reduce the bulk, and reduce the cost. is there. Further, the physical properties of the aqueous solution-absorbing material are preferably those having toughness after absorbing moisture, and are preferably not easily destroyed when compressed, stretched, or bent, for example. When an aqueous gel excellent in mechanical properties is used as an aqueous solution absorbent material, gel blocking during absorption is unlikely to occur.

  The aqueous solution-absorbing material comprising the organic / inorganic composite polyacrylamide-based aqueous gel of the present invention and / or a dried product thereof as a constituent component exhibits good mechanical properties even after water absorption, for example, withstands compression, tension or bending deformation. Has toughness. Specifically, an organic / inorganic composite polyacrylamide-based aqueous gel having a diameter of 5.5 mm and a length of 30 mm containing 10 times the amount of water (weight ratio) of a polymer of an acrylamide compound (polyacrylamide component) is as follows: The shape is not destroyed even when it is compressively deformed to a thickness of 1/3 or less, particularly preferably 1/5 or less in the thickness direction.

  Similarly, an organic / inorganic composite polyacrylamide-based aqueous gel having a diameter of 5.5 mm and a length of 30 mm containing 10 times the amount (weight ratio) of a polymer of an acrylamide compound (polyacrylamide component) (weight ratio) is The shape is not destroyed even when stretched and deformed to a length of 2 times or more, particularly preferably a length of 4 times or more in the length direction.

  Furthermore, an organic / inorganic composite polyacrylamide aqueous gel having a diameter of 5.5 mm and a length of 30 mm containing 10 times the amount (weight ratio) of a polymer of acrylamide compounds (polyacrylamide component) is Even if it is bent and deformed to an angle of 100 degrees or more at the center point, particularly preferably to an angle of 150 degrees or more, the shape is not destroyed.

  The dried organic / inorganic composite polyacrylamide-based aqueous gel used in the aqueous solution-absorbing material of the present invention can be obtained by drying the organic / inorganic composite polyacrylamide-based aqueous gel obtained by polymerization, Obtained by processing such as classification. Drying can be performed by a publicly known and commonly used drying method such as hot air circulation drying or reduced pressure drying. Also, the shape of the dried body or aqueous gel is not particularly limited, such as spherical, scale-like, amorphous powder, film, fiber, etc. Also, the size is, for example, in the case of powder, the average particle size is usually 10 to 10 Although a thing of 1,000 micrometers is used, it is not specifically limited.

  The organic / inorganic composite polyacrylamide-based aqueous gel and / or dried product thereof used for the aqueous solution absorbing material of the present invention contains clay mineral, but since the clay mineral is finely dispersed, the aqueous solution absorbing material is transparent. It is possible that there is. Therefore, when absorbing a colored aqueous solution or body fluid, the state of absorption can be detected by light transmission or light reflection. Further, when other organic components or inorganic components are dispersed in the aqueous gel in advance, there is an advantage that the dispersed state can be clearly grasped.

  The aqueous solution-absorbing material of the present invention may use an organic / inorganic composite polyacrylamide-based aqueous gel and / or a dried product thereof alone, but if necessary, other water-soluble polymer, hydrophilic polymer, hydrophobic polymer, You may use it in combination with surfactant, an inorganic filler, etc.

  Organic / inorganic composite polyacrylamide-based aqueous gel and / or dried product thereof can be processed into any shape such as granular, scale-like, fibrous, and film-like, and combined with other materials (dispersed, laminated, etc.) In addition, an anionic activator (eg, alkyl sulfate), a denaturing agent such as urea or formamide, an antioxidant (eg, 2-mercaptoethanol), a water-soluble polymer (eg, polyvinyl alcohol) , Polyethylene glycol), agarose, wetting agent (eg glycerin), bactericides, colorants, fragrances, deodorants, inorganic powders, organic fibrous materials, etc. at any stage in aqueous gels and dried products Can be used.

  The aqueous solution absorbing material of the present invention having the above-described features can be effectively used for sanitary products such as disposable diapers and sanitary products. Such hygiene products are preferably used in the form of commercially available hygiene products in combination with other known materials and components. For example, in a paper diaper, a porous and hydrophobic non-woven fabric is placed on the surface in contact with the skin, and cotton-like pulp is placed as the primary absorbent to improve the absorption rate. Alternatively, the aqueous solution-absorbing material of the present invention is placed in the form of a powder or a thin film in order to increase the amount of absorption and in close contact with the primary absorbent.

In addition, it is also performed to prevent leakage of urine around the disposable diaper with shrinkable rubber or fixing adhesive tape. In the sanitary napkin, the aqueous absorbent material of the present invention, which has been powdered, mixed with pulp and processed into a sheet, is laminated with rayon pulp or absorbent paper, and the surface layer is covered with nonwoven fabric or polyethylene laminated paper. By adopting a structure, body fluid such as blood can be rapidly absorbed. The aqueous solution-absorbing material of the present invention can absorb an organic solvent mixed with water or dissolved in water in addition to aqueous solutions such as water and body fluids, and is useful for absorption and separation of these. .

  EXAMPLES Next, although an Example demonstrates this invention more concretely, this invention is not limited only to the Example shown below from the first.

(Examples 1-4)
The clay mineral includes a water-swellable synthetic hectorite (trademark Laponite XLG, manufactured by Nippon Silica Co., Ltd.) having a composition of [Mg _5.34 Li _0.66 Si ₈ O ₂₀ (OH) ₄ ] Na ⁺ _0.66. Used by vacuum drying at 100 ° C. for 2 hours. As an organic monomer, N, N-dimethylacrylamide (DMAA: Wako Pure Chemical Industries, Ltd.) is used in Example 1, acryloylmorpholine (ACMO: Kojin Co., Ltd.) is used in Example 2, and N, N is used in Example 3. -Diethylacrylamide (DEAA: Wako Pure Chemical Industries, Ltd.) was used in Example 4, and N-isopropylacrylamide (IPAA: manufactured by Kojin Co., Ltd.) was used.

  DMAA, ACMO, and DEAA were used after removing a polymerization inhibitor using a silica gel column (manufactured by Merck) in a volume of 80 ml with respect to 100 ml of an organic monomer. IPAA was recrystallized using a mixed solvent of toluene and hexane (1/10 weight ratio) and purified into colorless needle crystals.

  As the polymerization initiator, potassium peroxodisulfate (PPS: manufactured by Kanto Chemical Co., Inc.) was used after being quantified with a microsyringe in the stock solution. As the catalyst, N, N, N ′, N′-tetramethylethylenediamine (TMEDA: manufactured by Kanto Chemical Co., Inc.) was used by diluting at a ratio of TMEDA / water = 160 μl / 20 g. In all of Examples 1 to 4, pure water obtained by distilling ion-exchanged water was used, and high-purity nitrogen was bubbled in advance for 3 hours or more to remove contained oxygen.

  In all Examples of the present invention, all operations before and after polymerization (all operations until the aqueous gel was taken out) were performed in a nitrogen atmosphere or a nitrogen stream from which oxygen was removed. Further, the catalyst and initiator aqueous solution were prepared in a nitrogen atmosphere in which oxygen was blocked in the same manner as the above operation.

  Into a two-necked flask set up in a water bath at 20 ° C. and purged with nitrogen, 56.88 g of pure water from which the dissolved oxygen was removed and a Teflon stirrer were placed. While stirring, 1.986 g of Laponite XLG was bubbled. A small and transparent solution was prepared by adding little by little while taking care not to enter. To this, 5.25 g of DMAA (Example 1: XLG / DMAA = 0.378 weight ratio), 7.5 g of ACMO (Example 2: XLG / ACMO = 0.265 weight ratio), or 6.75 g of DEAA (Example 3: XLG / DEAA = 0.294 weight ratio) or IPAA 6.0 g (Example 4: XLG / IPAA = 0.331 weight ratio) was added and stirred until a colorless transparent solution was obtained.

  Next, after the flask was cooled in an ice bath, 48 μl of TMEDA that had been separately cooled in an ice bath was added and stirred for 30 seconds, and then 3.18 g of an aqueous PPS solution that had been separately cooled in an ice bath. Was added and stirred for 30 seconds to obtain a colorless transparent solution. The solution was then held for 1 minute and then allowed to stand in a warm water bath at 20 ° C. for 8 hours to complete the polymerization. In the flask, an elastic organic / inorganic composite polyacrylamide aqueous gel in which the entire system was gelled (the contents did not move even when the container was placed on the side) was obtained.

  Neither a non-uniform or opaque clay mineral or polymer agglomeration was observed in the gel. The transparency of the aqueous gel immediately after polymerization was uniform and transparent in Examples 1, 2, and 4, and uniform and translucent in Example 3. The gel was weighed, cut into about 5 mm square, and then swollen in a large amount of water at 5 ° C. and vacuum-dried at 80 ° C. twice. Then, it vacuum-dried at 100 degreeC for 8 hours, the dry body of the aqueous gel was obtained, and the yield after refinement | purification was calculated | required from the weighing. The yield after purification of Examples 1 to 4 was as high as 99% by weight or more.

  Further, the obtained dried aqueous gel was pulverized to an average particle size of about 300 μm, and then equilibrium-swelled in 20 ° C. water. The weight of the resulting swollen equilibrium aqueous gel is 52 times (Example 1), 41 times (Example 2), 35 times (Example 3), 60 times (Example 4) of the corresponding dry weight, A high water absorption was shown.

(Examples 5 to 8)
Clay mineral prepared in the same manner as in Examples 1 to 4 except that 6.0 g of DMAA (Example 5), ACMO (Example 6), DEAA (Example 7), and IPAA (Example 8) are all used. A colorless and transparent aqueous solution containing organic monomer, TMEDA, and PPS is placed in a glass tube container with an inner diameter of 5.5 mm and a length of 150 mm with a sealed stopper, and is similarly polymerized at 20 ° C. for 8 hours in a state where oxygen is blocked. An organic / inorganic composite polyacrylamide-based aqueous gel with a water content was obtained.

  The aqueous gel contained 10 times as much water as the polyacrylamide component. Taking out a rod-shaped aqueous gel with an outer diameter of 5.5 mm from a glass tube, using a sample cut to a length of 30 mm, a test to compress to 1/3 and 1/5 in the thickness direction, and double in the length direction And the test which extends | stretches to 4 time and the test which carries out bending deformation to the angle of 100 degree | times, 150 degree | times and more at the center point of the length were done. As a result, in any of the samples of Examples 5 to 8, the shape was not broken, cracked, or lost, and returned to the original state in the above test. In all of the bending deformation tests, the deformation returned to the original state after the test without causing breakage or cracking even when the deformation was 180 degrees or more.

(Examples 9 to 14)
The amount of clay mineral (Laponite XLG) is 0.396 g (Example 9, 10: XLG / IPAA = 0.066 weight ratio), 0.792 g (Example 11, 12: XLG / IPAA = 0.132 weight ratio) 3.564 g (Examples 13 and 14: XLG / IPAA = 0.594 weight ratio) Examples 9, 11, and 13 were the same as Example 4 except that the examples 10, 12, and 14 were used. Was polymerized in the same manner as in Example 8 to prepare an organic / inorganic composite polyacrylamide-based aqueous gel.

  In Examples 9 to 14, a transparent uniform aqueous gel was obtained at 20 ° C. in all cases. The weight of the aqueous gel equilibrated and swollen in 20 ° C. water measured in the same manner as in Example 4 was 112 times (Example 9), 71 times (Example 11), and 54 times (Example 13) of the corresponding dry weight. )Met. In Examples 10, 12, and 14, in the compression, stretching, and bending deformation tests under the same conditions as Example 8 using a rod-shaped aqueous gel with a length of 30 mm, any sample of Examples 10, 12, and 14 was used. However, the shape was not destroyed, cracked, or lost, and the original state was restored. Also, in the bending deformation test, no damage or crack occurred even when the deformation was 180 degrees or more, and the original state was restored after the test.

(Comparative Examples 1-4)
After adding IPAA without using clay minerals, the organic cross-linking agent N, N′-methylenebisacrylamide (BIS) (manufactured by Kanto Chemical Co., Ltd.) was added at 1 mol% of IPAA (Comparative Examples 1 and 3), 5 mol. % (Comparative Examples 2 and 4), except that it was added and used, the experiment of Comparative Examples 1 and 2 was conducted in the same manner as in Example 4, the experiment of Comparative Examples 3 and 4 was conducted in the same manner as in Example 8, Was polymerized at 20 ° C. for 8 hours to obtain an aqueous gel.

  In Comparative Examples 1 and 3, colorless and transparent gels were obtained, and in Comparative Examples 2 and 4, white turbid gels were obtained. All gels were brittle with no toughness. Note that the gel became cloudy because the crosslink density was not uniform in the system by increasing the concentration of the crosslinker, resulting in a heterogeneous crosslink structure that caused scattering on the scale of visible light. The weight of the aqueous gel equilibrated and swollen in 20 ° C. water measured in the same manner as in Example 4 was 15 times (Comparative Example 1) and 8 times (Comparative Example 2) the corresponding dry weight.

  In Comparative Examples 3 and 4, a rod-shaped aqueous gel having a length of 30 mm was used in the same manner as in Example 8, and compression, stretching, and bending deformation tests were performed under the same conditions as in Example 8. As a result, in both Comparative Examples 3 and 4, cracks are caused by compression deformation in the thickness direction 1/3, stretching deformation in the length direction twice, and bending deformation of 100 degrees at the center of the length. , The shape was destroyed.

(Comparative Examples 5 and 6)
After adding DMAA monomer without using clay mineral, organic cross-linking agent N, N′-methylenebisacrylamide (BIS) (manufactured by Kanto Chemical Co., Ltd.) was added to 1 mol% of DMAA or IPAA (Comparative Example 5), 5 Except for the addition of mol% (Comparative Example 6), the experiments of Comparative Examples 5 and 6 were conducted in the same manner as in Example 5 and polymerized at 20 ° C. for 8 hours to obtain an aqueous gel. In Comparative Example 5, a colorless and transparent gel was obtained, and in Comparative Example 6, a cloudy gel was obtained. However, each gel was a brittle gel without toughness.

  Using a rod-like aqueous gel with a length of 30 mm in the same manner as in Example 5, compression, stretching, and bending deformation tests were performed under the same test conditions as in Example 5. As a result, in all of Comparative Examples 5 and 6, cracks were generated by compressive deformation in the thickness direction 1/3, stretch deformation in the length direction twice, and bending deformation of 100 degrees at the center of the length. Or the shape was destroyed.

Effect of the invention

  The absorbent sanitary material comprising the organic / inorganic composite polyacrylamide-based aqueous gel and / or dried product thereof according to the present invention is superior in liquid absorbability in a gel dried product compared to a conventional aqueous gel, and in a gel state. It is excellent in durability against mechanical deformation such as pressure, tension and bending, and is useful as an aqueous solution absorbing material, particularly an aqueous solution absorbing material for hygiene products.

Claims (10)

(A) a polymer of an acrylamide compound, (B) a water-swellable clay mineral that can be uniformly dispersed in water, and (C) water as three components, and (A) and 1-10
Aqueous solution absorbent material and organic-inorganic composite polyacrylamide aqueous gel components that in the three-dimensional network consisting of dispersed nanometer level thickness of the layer (B) is (C) are included.
(A) Polymerized acrylamide compound and (B) Uniformly dispersible in water
A water swellable clay mineral as a constituent, and (A) and 1-10 layers of nanometer level
An organic / inorganic composite polyacrylamide-based aqueous gel consisting of (B) dispersed in thickness
An aqueous solution absorbing material as a constituent component.
(B) It is obtained by polymerizing (A) an acrylamide compound in the coexistence of water-swellable clay mineral dispersed at a nanometer level of 1 to 10 layers that can be uniformly dispersed in water and (C) water. An aqueous solution absorbing material comprising an organic / inorganic composite polyacrylamide-based aqueous gel or a dried product thereof as a constituent component.
(B) according to claim 1-3 noise polymer weight ratio of the homogeneous dispersible water-swellable clay mineral / (A) acrylamide compound in water, characterized in that from 0.01 to 10
2. The aqueous solution absorbing material according to item 1 .
(B) The aqueous solution absorbing material according to any one of claims 1 to 4 , wherein the water-swellable clay mineral that can be uniformly dispersed in water is water-swellable smectite.
The aqueous solution-absorbing material according to any one of claims 1 to 5 , wherein the weight of the organic / inorganic composite polyacrylamide-based aqueous gel at the time of equilibrium swelling at 20 ° C is 20 times or more the weight of the dry body. .
(A) acrylamide compound of the polymer of 10-fold amount of water laden organic-inorganic composite polyacrylamide-based aqueous gel (diameter 5.5mm (weight ratio), a length of 30mm
Rod-like) is also compressed to one-third or less of the thickness in the thickness direction, an aqueous solution absorbent material of any one of claim 1 to 5, the shape is characterized in that not destroyed.
(A) acrylamide compound of the polymer of 10-fold amount of water laden organic-inorganic composite polyacrylamide-based aqueous gel (diameter 5.5mm (weight ratio), a length of 30mm
Even rod-like) is stretched to twice or more the length in the longitudinal direction, an aqueous solution absorbent material of any one of claim 1 to 5, characterized in that its shape is not destroyed.
(A) acrylamide compound of the polymer of 10-fold amount of water laden organic-inorganic composite polyacrylamide-based aqueous gel (diameter 5.5mm (weight ratio), a length of 30mm
Rod-like) is, be deformed bent 100 degrees over an angle in the length center point, the aqueous solution absorbent material of any one of claim 1 to 5, characterized in that its shape is not destroyed.
Sanitary goods using the aqueous solution absorbent material according to any one of claims 1 to 9 .