JPH0859753A - Ground humectant - Google Patents

Abstract

PURPOSE: To obtain the subject humectant agent hardly being affected by an electrolyte such as an inorganic salt, having excellent chemical stability, moisture retention, water retention, water permeability, freeze resistance and safety, comprising a specific cross-linked material of a polymer as a water-absorbing resin. CONSTITUTION: This gland humectant contains a cross-linked material of a polymer which is a cross-linked material of a (co)polymer of an N- vinylcarboxylic acid amide of formula I (R<1> and R<2> are each H or methyl) and has liquid absorbing ability of 10 times as much 1% aqueous solution of calcium chloride as the empty weight, as a water-absorbing resin. The cross linked material of the polymer preferably comprises a repeating unit (U1) of formula II and a repeating unit (U2) of formula III [R<3> is R<1> ; X is a group of the formula COOR<4> (R<4> is H or a 1-4C alkyl) or a group of the formula COOM<1> (M<1> is an alkali metal)], is cross-linked with a cross-linking agent containing two or more vinyl groups in the molecule and has the molar ratio of U1 to U2 of (100:0)-(50:50).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a ground using a highly safe water absorbent resin, which is nonionic and excellent in chemical stability and shows a certain water retention effect without being affected by electrolytes such as inorganic salts. Regarding moisturizers. For example, grounds such as schools, tennis courts, volleyball courts, basketball courts, soccer fields, rugby fields, gateball fields, baseball fields, horse fields, field tracks, etc.
In addition, in the grounds of promenades, temples, unpaved roads, plazas, etc., prevent sand dust in the ground during dry weather, improve drainage of the ground in rainy weather, and further improve construction roads, agricultural and horticultural grounds, etc. It is related to ground moisturizer used for the method of fixing sand and soil on flat ground, scattering of soil, prevention of erosion, etc., and is used in a wide range of fields such as civil engineering and construction fields such as landscaping and land preparation, agriculture, forestry, etc. It is possible.

[0002]

2. Description of the Related Art A gland formed by using natural soil or natural artificial soil as a constituent material of a gland is suitable for a human body because it has a proper elasticity and a natural feel as compared with a gland made of a synthetic resin. It is said. But,
The one using such earth as the ground surface layer has a problem that sand dust is liable to stand up during dry weather, and water collects in a muddy state in rainy weather. On the other hand, all-weather grounds made of completely synthetic resin are also widely used.
This is made by pouring synthetic resin on the surface of the ground and hardened, and has the advantage that it can be used after rain and is easy to maintain and maintain, but it has a drawback in that it is inferior in usability and easily tired. It was Therefore, conventionally, a gland wetting agent such as calcium chloride or magnesium chloride has been used for the purpose of keeping the humidity constant against a gland using a natural soil or a natural artificial soil and preventing dust dust. These moisturizers have freezing point depressing action and have the advantage that they are easy to use, but if you create a gland using only these, they will run away in the rain or become weak immediately after rain. It has drawbacks such as the inability to use the ground, and since it is irritating, it was inconvenient when the ground was injured or when it got into the eyes with dust.

As a means for solving these problems, in recent years, a method of mixing a water-absorbent resin with the surface soil (Japanese Patent Laid-Open No. 59-59).
No. 72301) has been proposed, and as a water absorbent resin, a sodium polyacrylate crosslinked product, a neutralized product of a starch-acrylic acid graft polymer, a saponified product of a vinyl acetate-acrylic acid ester copolymerized crosslinked product, and isobutylene have been conventionally used. −
A neutralized product of a maleic anhydride copolymer crosslinked product has been used. However, these conventional methods using a water-absorbent resin have a problem that the effect is not maintained for a long period of time, although the dustproof property and the water permeability are good at the initial stage after the formation of the ground. As a result of studying this phenomenon by the present inventors, it was considered that this is due to the drawback that the water absorbent resin irreversibly loses its water absorbing ability due to the metal ions contained in the soil. Also, in the presence of slaked lime used for line drawing and the like, calcium chloride and magnesium chloride as freezing point depressants, or in the surface soil of the ground using cement as a solidifying agent, these conventional water-absorbent resins have their water-absorbing ability. Could not be fully exerted, and the effect of improving the ground could not be fully exerted. That is, it is important to maintain a sufficient water absorption capacity even in the presence of calcium chloride, magnesium chloride and the like. Further, when the soil is acidic, it is necessary to neutralize the soil in advance with these water absorbent resins in order to maintain a predetermined water retention property, which is extremely troublesome in work. In other words, it was difficult for the conventional method to keep the ground constant because the soil environment had a great influence. Further, these conventional resins have drawbacks such as being easily affected by light or microorganisms, and the effect of improving the ground cannot be maintained for a long period of time.

Further, since the conventional resin is sprayed or mixed in the soil as it is, it has the following problems. (A) When mixed, it easily scatters due to wind pressure such as wind, or gels and sticks to each other due to some sweat or rain on the hands, and it is extremely inconvenient to handle and handle. (B) The water-absorbent resin that has absorbed water blocks the gas phase portion in the soil and impairs air permeability. (C) In the case of soil in a wet state, the water-absorbent resin quickly absorbs water in the soil and easily hardens at the surface layer of the ground, resulting in uneven mixing, resulting in reduced moisturizing effect and uniform mixing with soil. It becomes difficult to do so, and the ground surface lacks stability.

[0005]

Under the circumstances, the present invention solves the above-mentioned problems of the prior art and provides a water-absorbent resin having high stability and safety and exhibiting a constant water absorption capacity under any environment. If necessary, a granular material containing a binder, or a sheet-shaped base material carrying a water-absorbent resin is mixed, sprinkled or spread over the ground soil to improve workability, and salts such as calcium chloride. , Even in the presence of metal ions and glycerin, ethylene glycol, etc., it maintains a high level of water retention, dustproofness, and water permeability for a long period of time, and even in wet soil, it can be mixed evenly. To provide a ground moisturizer that does not easily scatter due to soil, etc. A.

[0006]

Means for Solving the Problems In view of such circumstances, as a result of intensive studies, it was found that the N-vinylacetamide polymer crosslinked product substantially exhibits a ground moisturizing effect. That is, the present invention is (A) a cross-linked product of a homopolymer or a copolymer of N-vinylcarboxylic acid amide represented by the following general formula (1), which has its own weight against 1% calcium chloride aqueous solution. A ground humectant characterized by containing a polymer cross-linked product having a liquid absorption capacity of 10 times as a water absorbent resin, wherein CH ₂ ═CHNR ¹ COR ² (1) [wherein R ¹ and R ² are respectively They may be the same or different and each represents a hydrogen atom or a methyl group. ] (B) The polymer crosslinked product is a repeating unit (2) of the following general formula:
And (3), which are crosslinked by a crosslinking agent having at least two vinyl groups in one molecule, and the molar ratio of the repeating units (2) and (3) is 100: 0 to 50:50. Regarding the ground moisturizer described in (1),

[Chemical 3] [In the formula, R ¹ and R ² may be the same or different and each represents a hydrogen atom or a methyl group. ]

[Chemical 4] [In the formula, R ³ represents a hydrogen atom or a methyl group, and X represents C
OOR ⁴ , COOM ¹ , CONHR ⁵ , CN, COR
⁶ , OCOR ⁷ , OR ⁸ or 2-oxo-pyrrolidin-1-yl is shown. However, R ⁴ and R ⁵ represent a hydrogen atom or a C ₁ -C ₄ alkyl group, and one hydrogen atom of the alkyl group can be replaced with OH, N (R ⁹ ) ₂ or SO ₃ M _2. , R ⁶ , R ⁷ , R ⁸ and R ⁹ are C _{1 to} C
_{4 represents} an alkyl group, and M ¹ and M ² represent an alkali metal. ]

(C) A ground moisturizer formed by granulating the polymer crosslinked product according to (A) or (B), or the polymer crosslinked product with a binder, (D) above (A) Alternatively, the invention relates to a ground moisturizer in which the polymer cross-linked product according to (B) is supported on a sheet-shaped base material. Further, in keeping a certain amount of water in the gland characterized by using the above (A) to (D), a stable and efficient moisturizing effect is brought about regardless of the presence of salts, metal ions, etc. in the gland. In addition, a method for improving dust resistance and water permeability is disclosed. Further, the present invention will be described in detail. The N-vinylcarboxylic acid amide represented by the general formula (1) is specifically represented by CH ₂ ═CHNR ¹ COR ² (1) [wherein R ¹ and R ² may be the same or different from each other. , A hydrogen atom or a methyl group. ] N-vinylformamide, N-vinylacetamide, N
-Methyl-N-vinylformamide, N-methyl-N-
Although vinylacetamide can be mentioned, excellent effects are exhibited by using N-vinylacetamide.

As the raw material monomer, only the N-vinylcarboxylic acid amide represented by the general formula (1) may be polymerized in the presence of a crosslinking agent, but other ethylenically unsaturated compounds may be copolymerized. Good. At this time, one or more N-vinylcarboxylic acid amides of the general formula (1) account for 50 or more of the raw material monomers.
It is important that the content is at least mol%. The polymer crosslinked product obtained by using the compound represented by the general formula (1) as a main component is a nonionic polymer unlike the conventional polycarboxylic acid-based water-absorbing resin which is a polymer electrolyte. Therefore, the presence of ions does not significantly reduce the water absorption capacity.
That is, this problem is solved when the liquid absorption capacity for a 1% calcium chloride aqueous solution is 10 times or more the self-weight of the crosslinked polymer. In addition, it does not swell too much and does not lift the soil, and unlike conventional nonionic resins such as acrylamide resins, it has excellent chemical stability such as being difficult to hydrolyze with alkali, and because it is alcohol-philic, it is glycerin, which is a freezing point depressant. Since it also absorbs ethylene glycol and ethylene glycol, it has the feature that stability is not reduced by these. Further, it is also characterized in that the safety of the monomer is high and there is no problem such as irritation of residual monomer. Therefore, the composition of the raw material monomer and the cross-linking agent of the polymer cross-linked product in the present invention is selected within the range in which the above-mentioned characteristics, which cannot be obtained by the conventional water absorbent resin, are improved. Therefore, in producing such a polymer crosslinked product, substantially, one or more 50 mol% or more of N-vinylcarboxylic acid amide represented by the general formula (1) is polymerized with a copolymerizable compound (monomer). Preferably. If it is less than 50 mol%, the water retention capacity in the presence of salts, metal ions, glycerin, ethylene glycol, etc. in the ground decreases and becomes chemically unstable, resulting in a decrease in the moisturizing effect.

Examples of the compound copolymerizable with the compound represented by the general formula (1) in the present invention include acrylic acid, methacrylic acid, sodium acrylate, sodium methacrylate, methyl acrylate, ethyl acrylate and propyl acrylate. , 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate,
N, N-dimethylaminoethyl acrylate, acrylamide, N, N-dimethylaminopropyl acrylamide, sodium 2-acrylamido-2-methyl-propanesulfonate, acrylonitrile, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, vinyl acetate, Methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, methyl methacrylate, ethyl methacrylate, propyl methacrylate,
2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, N, N-dimethylaminoethyl methacrylate, methacrylamide, N, N-dimethylaminopropyl methacrylamide, N-vinyl-2-
Examples include compounds such as pyrrolidone. These compounds can be used in combination.

The types of cross-linking agents used in the present invention include N, N'-methylenebisacrylamide, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol. Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, divinylbenzene, divinyl ether, N, N'-diacetyl-N, N'-divinyl-1,
4-bisaminomethylcyclohexane, N, N'-xylylenebis (N-vinylacetamide), N, N'-3
-Oxa-1,5-pentylenebis (N-vinylacetamide), N, N'-1,6-hexylenebis (N-vinylacetamide), N, N'-1,4-butylenebis (N-vinylacetamide), tetra Unsaturated groups in one molecule, such as allyloxyethane, pentaerythritol allyl ether, diethylene glycol diallyl ether, tetraallyl pyromellitic acid, triallyl trimellitate, diallyl adipate, diallyl terephthalate, diallyl isophthalate and divinyl adipate, for example, Examples thereof include compounds having at least two vinyl groups, and these crosslinkable monomers may be used alone or in combination of two or more.

The amount of the crosslinking agent used is based on the starting compound.
The cross-linking agent / raw material monomer molar ratio is 10/90 to
It is selected from the range of 0.0001 / 99.9999, with the range of 1/99 to 0.0005 / 99.99995 being particularly preferred. When the amount of the cross-linking agent is more than 10/90 in terms of the cross-linking agent / monomer molar ratio, the cross-linking density of the resulting water-absorbent resin becomes too high, so that the swelling rate becomes very small and the water-absorbing agent is substantially absorbed. The effect as a resin cannot be exhibited.
Further, the cross-linking agent / raw material monomer ratio is 0.000 in molar ratio.
When the amount of the cross-linking agent is less than 1 / 99.9999, the formation of water-soluble or hydrophilic polymer which is not involved in the cross-linking increases, and the effect as a water-absorbent resin cannot be exerted substantially.

In the present invention, it is also possible to obtain a crosslinked polymer by adding a crosslinking agent after polymerizing a monomer component. Examples of the cross-linking agent include inorganic acid salts such as aluminum, calcium, magnesium, manganese, and zinc, organic acid salts, chlorides, hydroxides, polyvalent metal compounds such as oxides, aldehydes such as formaldehyde, and ethylene glycol diglycidyl. Examples thereof include water-soluble epoxy compounds such as ether, glycerin diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and these crosslinking agents may be used alone or in combination.
More than one species can be used.

In producing the crosslinked polymer according to the present invention, methods such as aqueous solution polymerization and reverse phase suspension polymerization can be used, but the method is not limited to these methods. As the polymerization initiator, a general radical polymerization initiator is generally used, and 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (2-imidazoline-2- Yl) propane] dihydrochloride, 2,2-azobis [2- (3,4,
5,6-Tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2-azobis [2- (5
-Hydroxy-3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,
Azo initiators such as 2′-azobis [2- (N-benzylamidino) propane] dihydrochloride, peroxides such as t-butylhydroperoxide and succinic acid peroxide, or peroxides or persulfates Examples include so-called redox catalysts in which a reducing agent such as triethanolamine and sodium thiosulfate is present in the same system.

In the present invention, the polymer cross-linked product is added to the ground moisturizer as a water absorbent resin. The amount of the water-absorbent resin added is 0.01 to 10.0% by weight, preferably 0.05 to 1.0% by weight, based on the total weight of the surface soil or the aggregate or solidifying material added as necessary. Appropriate.
If it is more than 10.0%, the amount of free water decreases, resulting in a decrease in water permeability. On the other hand, if it is less than 0.01%, sufficient water retention, water permeability and dustproofness cannot be obtained. The blending amount here means the weight% of the water-absorbent resin with respect to the surface soil main material in the anhydrous state.

The surface soil main material used in the present invention is not limited to these, but any type of soil generally used for the ground surface layer may be used, such as natural soil such as clay, antuca or edge. Natural artificial soil such as mud powder,
Alternatively, it is a mixed soil of natural soil and natural artificial soil. After mixing or spraying the above water-absorbent resin on these surface soils, the water-absorbent resin may be compacted in a hydrated state, or may be mixed with water to be sprinkled with water in a gland that has been laid in advance. . The shape of the water-absorbent resin is not particularly limited and may be any shape such as powdery granules, flakes, pearls and fibers.

In the present invention, if necessary, an aggregate and / or a solidifying agent can be added to the surface soil. Examples of aggregates that can be added include sand, gravel, perlite, and vermiculite. As the solidifying agent, for example,
Examples include cement, gypsum, quicklime and slaked lime. These are effective for improving the compressive strength of the surface soil and improving the water permeability. The preferable addition amount is 0.1 to 50% by weight as an aggregate and 0.01 to 10% by weight as a solidifying agent. If it is out of this range, the elasticity of the ground surface will be lost.

In the present invention, the water-absorbent resin can be formed into a granular shape if necessary, and even in the soil in a wet state, the water-absorbent resin can be uniformly mixed and can be prevented from scattering by wind or the like. In this granulation, a binder can be used if necessary, and examples of the binder used include water-soluble synthetic polymers (for example, poly-N-vinylacetamide, poly-N-vinylformamide, poly-N). -Methyl-N-vinylformamide, isobutylene-maleic anhydride copolymer, polyacrylate, vinyl acetate-acrylate copolymer, sulfonated polystyrene, polyvinyl alcohol and its derivatives, polymaleic anhydride and Derivatives, partial hydrolysates of polyacrylamide, etc.), water-soluble anti-synthetic polymers (eg carboxymethyl starch, methyl cellulose, carboxydimethyl cellulose, carboxymethyl cellulose, hydroxyalkyl cellulose etc.), natural polysaccharides or monosaccharides (eg As chitosa , Molasses, glucose, guar gum, sodium alginate, starch, gum arabic, mannan,
Maltose, etc.), natural fiber (eg peat moss,
Such as water moss). Two or more kinds of the above binders may be used in combination. The amount of the binder used is usually 30% or less, preferably 20% or less, based on the ground moisturizer formed in a granular form. If the amount used exceeds 30%, the gland moisturizer becomes a strong substance, and the water absorption rate when contacting with water decreases.

In the present invention, there is no particular limitation on the method of molding into granules. For example, a method of mixing a water-absorbent resin and, if necessary, a binder, extrusion compression molding, and cutting into a predetermined length, a tableting machine is used. Molding method, a method of molding using a screw type extruder, a method of introducing a water-absorbent resin into a drum type granulator or a dish type granulator, and granulating while adding a binder. To be The shape and size of the granular molded article can be arbitrarily adjusted according to the use scene, and is not particularly limited, but in terms of handling during use and stability of the shape, the particle size is usually 0.5. It is 10 mm, preferably 2-8 mm. Substantially, particles having a diameter of 2 to 8 mm exceeding 60% by weight may be used.

In order to obtain a sheet-shaped ground moisturizer in the present invention, paper, wood, metal, glass fiber, cloth (nell,
Woven fabrics, non-woven fabrics, etc.), synthetic resins (polyurethane, ethylene vinyl acetate copolymer, polyvinyl chloride, polyethylene terephthalate, polyethylene, polyester, etc.), or cellulose derivatives and molded products such as laminated films of these and plastic films, sheets A water absorbing resin is carried on a support such as (foil). In the present invention, a ground moisturizer as an extender, an organic fiber or powder as a granulating agent (for example, pulp, silk, sawdust, rice bran, pulp powder, etc.), an inorganic powder (for example, zeolite, silica sand, silica, white carbon, Hydrotalcite,
Talc, perlite, permiculite, bentonite, peat, etc.) can be added in an appropriate amount if necessary. In addition, an antioxidant, an antifungal agent, a trace element, glycerin, ethylene glycol, a surfactant, a resin emulsion, water, etc. can be added if necessary.
The amount of these auxiliary components is usually 0 to 10%.

In the present invention, the occurrence of frost columns in winter,
It is also possible to add a freezing point depressant to prevent freezing. As the freezing point depressant, organic substances such as glycerin and ethylene glycol, or inorganic salts such as sodium chloride, magnesium chloride and calcium chloride can be used.
The addition method is not limited to this,
It is also possible to mix it with water that is sprinkled on a ground that has been laid in advance and spray it together with water. It is appropriate that the amount of addition is 0.5 to 5 wt% with respect to water.

As described above, in the present invention, the water absorbent resin is mixed in the surface soil, and the water absorbent resin exists in the soil in the state of absorbing a large amount of water. Even if the surface is about to dry, this stored water will moisten the entire surface soil, the ground surface will not become abnormally dry, and dust will stand or the elasticity of the ground surface will decrease. There is no. Further, in the present invention, free water in the soil is reduced and the porosity in the soil is increased due to the water absorbing function of the water absorbent resin, and as a result, the water permeability is improved. Further, since the rainwater has good water permeability and drainage, the gland is unlikely to become soft after rainfall, and in the case of normal rain, the gland can be used immediately after rain. Further, in the present invention, since the free water in the soil is reduced by the action of the water absorbent resin, the thermal conductivity of the soil is lowered and the freezing is less likely to occur. When a freezing point depressant is used, freezing is less likely to occur and it is particularly suitable for use in cold regions. Since the water-absorbent resin is not decomposed by microorganisms, its effectiveness lasts semipermanently by supplementing the mechanical loss once / year.

[0022]

EXAMPLES The usefulness of the present invention is described below with reference to examples, but the present invention is not limited thereto.

Example 1 200 g of N-vinylacetamide and 0.1 g of N, N'-methylenebisacrylamide were dissolved in 750 g of water,
It was put in a 1 L three-necked separable flask. A nitrogen inlet tube, a thermometer holder and an exhaust tube were set in the three-necked flask and immersed in a constant temperature bath at 30 ° C. Nitrogen was bubbled at a rate of 1 L / min for 30 minutes to remove dissolved oxygen, and then 2.
What dissolved 0.40 g of 2'-azobis (2-amidinopropane) dihydrochloride in 49.6 g of water was added to the reaction solution. The flask was placed in a heat-insulated container, the nitrogen flow rate was reduced to 0.1 L / min, and the flask was allowed to stand. After 16 hours, the gel content was taken out, subdivided with a mincer (household meat grinder), dehydrated with acetone, and dried at 105 ° C for 5 hours. The dry gel thus obtained is crushed and classified to 4
The final product was prepared to 8 to 100 mesh. The water absorption capacity of this water absorbent resin for an aqueous 1% calcium chloride solution was 20 times the dead weight of the water absorbent resin. The ground moisturizing effect and dustproof effect of this final product were investigated.

Example-2 100 g of N-vinylformamide and 100 g of acrylamide, N, N'-diacetyl-N, N'-divinyl-1,4-bisaminomethylcyclohexane 44.80
Using g, the reaction was carried out in the same manner as in Example 1 and post-treatment was carried out. The water absorption capacity of this water absorbent resin for an aqueous 1% calcium chloride solution was 25 times the dead weight of the water absorbent resin.

Example 3 139.5 g of N-vinylacetamide and 60.5 g of methyl acrylate were dissolved in 750 g of water, and 0.023 g of divinylbenzene was dissolved in 1 L of water. It was put in a separable flask. A nitrogen inlet tube, a thermometer holder and an exhaust tube were set in the three-necked flask and immersed in a constant temperature bath at 30 ° C. Nitrogen was bubbled at a rate of 1 L / min for 30 minutes to remove dissolved oxygen, and then 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride was added to 0.4
What melt | dissolved 0 g in 49.6 g of water was added to the reaction liquid. Put the flask in a heat-insulated container and set the nitrogen flow rate to 0.1 L /
It decreased to a minute and was left to stand. Thereafter, post-treatment was carried out in the same manner as in Example 1 to obtain a final product. The water absorption capacity of this water absorbent resin for a 1% aqueous solution of calcium chloride was 15 times the dead weight of the water absorbent resin.

Comparative Example-1 81.5 g of N-vinylacetamide and 118.5 g of acrylonitrile, N, N'-diacetyl-N, N'-
0.1 g of divinyl-1,4-bisaminomethylcyclohexane was reacted in exactly the same manner as in Example 1 and post-treated. The water absorption capacity of this water absorbent resin for a 1% calcium chloride aqueous solution was 8 times the dead weight of the water absorbent resin.

Comparative Example-2 71 g of N-vinylformamide and acrylamide 1
29 g, N, N'-diacetyl-N, N'-divinyl-
1,4-bisaminomethylcyclohexane 123.2 g
Was reacted in exactly the same manner as in Example 1 and post-treated. The water absorption capacity of this water absorbent resin for a 1% calcium chloride aqueous solution was 5 times the weight of the water absorbent resin.

Comparative Examples-3 to 6 Table 1 shows the results of a moisture retention test and a dustproof test conducted in the same manner as in Example 1 with respect to three kinds of commercially available water-absorbent resins. The water absorbent resin is shown below. Comparative Example-3 Sulfonyl Hydrochloric Acid Acrylic Water-Absorbent Resin AQUALIC CS: NIPPON SHOKUBAI CHEMICAL INDUSTRIES, LTD. Comparative Example-4 Starch-acrylic acid graft copolymer neutralized product Sunwet IM-1500: Sanyo Chemical Industry Co., Ltd. Comparative Example-5 Na salt of vinyl acetate-methyl acrylate copolymer saponified Sumikagel S-50: Sumitomo Chemical Co., Ltd. Comparative Example-6 Acrylate cross-linking water-absorbent resin Diawet AL-III: Mitsubishi Yuka Co., Ltd.

Use Example 1 70 parts by weight of clay, 27.5 parts by weight of sand, 2 parts by weight of ordinary Portland cement and 0.5 parts by weight of the water-absorbent resin of the above-mentioned Examples and Comparative Examples were thoroughly mixed, and then 30c in width.
To a planter made of m having a length of 30 cm and a depth of 20 cm, a depth of 15 cm was added, and a 2 kg pressure roller (Yoshimitsu Seiki) was used for compaction to create a simulated ground. 4 liters of a 5% calcium chloride aqueous solution was evenly sprinkled on this, and the weight of the planter was measured as the water content. This was put in a thermostat of 30 degrees for 7 days, and the weight of the planter was measured again. The water content after 7 days when the water content immediately after watering was set to 100 is shown in Table 1 as a relative water content. In the above test, air was blown with a blower to observe the dust scattering state on the surface of the simulated gland after putting it in a thermostat of 30 degrees for 7 days. The observation results are shown in Table 1.

[0030]

[Table 1]

Use Example 2 80 parts of magnesia carbonate lime, 5 parts of water-absorbent resin and 10 parts of peat moss were mixed with a ribbon mixer, and then 5 parts of molasses and linear N-vinylacetamide homopolymer 0.5 with further stirring. Parts were added. This mixture was molded into a columnar shape using a screw type extruder equipped with a die having a hole shape of 5 mm and cut into a length of about 7 mm to obtain a ground moisturizing agent of the present invention. Volcanic gravel and crushed stone were spread to a thickness of 10 to 20 cm on a roadbed in a vinyl house to form a foundation, and a surface soil was spread to a thickness of 4 cm and compacted with a roller. As the surface soil, mainly Antuker was used, which was mixed with 2% by weight of the cylindrical ground moisturizer and sufficiently stirred. After the break-spread this way, surface soil that was created, the water 1m ² per 8
kg of water was sprinkled, and roller rolling pressure was applied. After that, the naturally dried state was observed for 2 days. As a result, in the examples, the surface soil is firmly tightened, is hard to dry, has little sand dust due to the wind of the fan, and has appropriate elasticity and sliding characteristics, and further has good water permeation and drainage properties, and is suitable for all surfaces. Was superior to that of the comparative example.

Use Example 3 A sheet was prepared by supporting a water absorbent resin on a non-woven fabric (70 g / m ² bionole: Showa Highpolymer Co., Ltd.) (about 30 wt% solid content ratio). This was laid between the surface layer and the intermediate layer, and a gland was formed in the same manner as in Use Example 2 except for the above.
8 g / m ² of water is added to the ground created in this way.
kg of water was sprinkled, and roller rolling pressure was applied. After that, the naturally dried state was observed for 2 days. As a result, in the examples, the surface soil is firmly tightened, is difficult to dry, has less sand dust due to the wind of the fan, and has suitable elasticity and slip characteristics, and further has good water permeation and drainage properties, and in all aspects. It was superior to that of the comparative example.

[0033]

INDUSTRIAL APPLICABILITY The present invention provides a highly safe water-absorbing resin which is nonionic and excellent in chemical stability and which exhibits a certain high water-retaining effect without being affected by electrolytes such as inorganic salts.
Granular moisturizer containing binder if necessary, or sheet-like base material impregnated with water-absorbent resin. Ground moisturizing effect is achieved by mixing or spraying the moisturizer on the ground. To be done. If the gland is moisturized by using the present invention, since the water retention is good, dust will not stand up even during dry weather, and
Because of its good water permeability, it drains well in rainy weather. Further, such a ground improving effect is not affected by the presence of an electrolyte such as an inorganic salt, and continues for a long time. Therefore, according to the method of using the ground moisturizer of the present invention, it is possible to greatly save the labor for maintaining the ground condition such as watering in a good condition.

Claims (4)

[Claims] 1. A cross-linked product of a homopolymer or a copolymer of N-vinylcarboxylic acid amide represented by the following general formula (1), which has a weight of 1 with respect to a 1% calcium chloride aqueous solution.
A ground moisturizer containing a polymer crosslinked product having a liquid absorption capacity of 0 times as a water absorbent resin. CH ₂ = CHNR ¹ COR ² (1) [In the formula, R ¹ and R ² may be the same or different and each represents a hydrogen atom or a methyl group. ] 2. A polymer crosslinked product is composed of repeating units (2) and (3) represented by the following general formula and is crosslinked by a crosslinking agent having at least two vinyl groups in one molecule, and the repeating unit (2) And the molar ratio of (3) is 100: 0 to 5
The ground moisturizer according to claim 1, which is 0:50. Embedded image [In the formula, R ¹ and R ² may be the same or different and each represents a hydrogen atom or a methyl group. ] [Chemical 2] [In the formula, R ³ represents a hydrogen atom or a methyl group, and X represents C
OOR ⁴ , COOM ¹ , CONHR ⁵ , CN, COR
⁶ , OCOR ⁷ , OR ⁸ or 2-oxo-pyrrolidin-1-yl is shown. However, R ⁴ and R ⁵ represent a hydrogen atom or a C ₁ -C ₄ alkyl group, and one hydrogen atom of the alkyl group can be replaced with OH, N (R ⁹ ) ₂ or SO ₃ M ^2. , R ⁶ , R ⁷ , R ⁸ and R ⁹ are C _{1 to} C
_{4 represents} an alkyl group, and M ¹ and M ² represent an alkali metal. ] 3. A ground moisturizer comprising the polymer cross-linked product according to claim 1 or 2, or the polymer cross-linked product formed into a granular shape by a binder. 4. A ground moisturizer comprising a crosslinked polymer according to claim 1 or 2 supported on a sheet-shaped base material.