JP4266867B2 - Fluidity reducing agent and method for treating hydrous soil - Google Patents

Description

The present invention relates to a fluidity reducing agent for hydrous soil and a method for treating hydrous soil. More specifically, a fluidity lowering agent suitably used for excavation work by the underground continuous wall construction method, the cast-in-place pile construction method, the muddy water shield construction method, and the like, and a method for treating hydrous soil using such a fluidity lowering agent About.

In excavation work such as the underground continuous wall method and the cast-in-place pile method, drilling mud is supplied to the drilling holes, and hydrous soil (generated soil) generated during excavation is discharged together with the drilling mud. The hydrous soil is usually in a slurry state and is dehydrated by a dehydrator such as a filter press. This dehydrated water-containing soil still contains a large amount of water and has strong fluidity. Therefore, when it is transported from the construction site as industrial waste, there is a problem that the dump truck cannot be piled up (that is, only a small amount can be transported), and free water (sewage) spills out from the truck, adversely affecting the environment. .
Thus, when processing as industrial waste, there was a problem that not only a large processing cost was required but also the environment was deteriorated. Furthermore, recently it has become difficult to secure the disposal site itself. On the other hand, in the shield method, a mudicide is supplied to the excavation hole, and the water-containing soil generated during excavation is discharged to the outside together with the mud additive. Although the water-containing soil from the shield method is less than the water-containing soil by the underground continuous wall method or the cast-in-place pile method, it still contains a large amount of water and is fluid. When the hydrous soil is also treated as industrial waste, there are the same problems as described above.
In order to eliminate such problems, it is easy to transport the hydrous soil by mixing cement or polymer with the hydrous soil, and recycle it as a resource for backfilling, agricultural and horticultural use. It has been tried to do.

Then, the following prior art is disclosed as a technique which improves a hydrous soil.
Regarding a method for improving water-containing soil using a carboxyl group-containing water-soluble polymer, a method of adding and mixing a carboxyl group-containing water-soluble polymer, which is a copolymer of sodium acrylate and acrylamide, with water-containing soil (for example, Patent Document 1) And an improving agent comprising a water-soluble polymer having a carboxyl group, which is a copolymer of sodium acrylate and acrylamide, and lime (for example, see Patent Document 2). However, the carboxyl group-containing water-soluble polymer used in these improved methods has a relatively slow dissolution rate in water, and it takes time to treat the water-containing soil. There was room for ingenuity to make it possible. In addition, when water-containing soil is improved, the carboxyl group-containing water-soluble polymer may be hydrolyzed to generate harmful ammonia gas. And there is room for contrivance to reduce costs.

Regarding a method for treating hydrous excavation residual soil that loses fluidity without removing moisture, a method of adding and kneading an acrylic water-soluble polymer or a cationic water-absorbing polymer resin, which is a fine particle dispersion having a particle size of 100 μm or less, (For example, refer to Patent Documents 3 and 4). In addition, regarding a method for treating excavated residue that gives good fluidity to excavated residue, after adding an additive composed of an anionic water-soluble polysaccharide and a superabsorbent resin to the excavated residue, a method of adding an aqueous aluminum salt solution (For example, refer to Patent Document 5). However, in these treatment methods, the fluidity of the hydrous soil can be sufficiently reduced, and the hydrous soil can be sufficiently solidified in a short time, making it easier to transport and reusing the hydrous soil. There was room for contrivance to give a sufficient degree of strength. In addition, there is room for improvement in order to exert sufficient effects on the ground mixed with seawater near the coast and the ground mixed with groundwater with a high hardness component content.

A method of adding a solidifying agent made of a specific polymer has been disclosed (see, for example, Patent Document 6) regarding a method for treating hydrous excavated soil that loses the fluidity of hydrous excavated soil. However, in this treatment method, there is room for ingenuity to perform the solidification treatment of the hydrous soil in a shorter time and to fully exhibit the performance of the solidifying agent even when water having a sufficiently high salinity concentration is mixed. there were. In addition, there is room for improvement in order to improve the storage stability and safety of the solidifying agent and to suitably reuse the hydrous soil after the solidification treatment.
JP-A-6-17052 (pages 2 and 3) Japanese Patent Laid-Open No. 4-34585 (page 2) Japanese Examined Patent Publication No. 6-91998 (page 2) JP-A-9-316450 (2nd page) JP 7-284800 A (2nd page) JP-A-9-302338 (2nd page)

The present invention has been made in view of the above situation, and exhibits excellent salt resistance and seawater resistance, and also sufficiently reduces the fluidity of the hydrous soil to facilitate transportation or filling of the hydrous soil. An object of the present invention is to provide a fluidity-reducing agent that can be recycled, used for agriculture or horticulture, or reused as a resource, and a method for treating hydrous soil using the fluidity-reducing agent.

The inventors of the present invention have made various studies on the improving agent for hydrous soil, and pay attention to the fact that those containing a water-soluble polymer can reduce the fluidity of hydrous soil, and (meth) acrylic acid (salt) Including a monomer and a water-soluble polymer obtained by polymerizing monomer components having an ether group and a (meth) acrylic acid ester monomer having a content ratio within a specific range. As a result, the amount of carboxylic acid attributed to the (meth) acrylic acid (salt) monomer is suppressed to an appropriate amount, and sufficient water solubility can be secured, so that excellent salt resistance and seawater resistance can be exhibited. At the same time, it has been found that it can be used as a fluidity reducing agent that can improve (solidify) water-containing soil in a short time. Furthermore, it has been found that the water-containing soil after improvement can be granulated by specifying the molecular weight of such a water-soluble polymer. And when such a fluidity reducing agent is used for hydrous soil, the fluidity can be sufficiently lowered and the hydrous soil can be improved, so that the hydrous soil can be easily transported and effective for backfilling, agricultural and horticultural use, etc. It is found that it can be reused as a resource or reused as a resource, and the water-containing soil is reused by adding a hydraulic material such as cement and granulating the water-containing soil sufficiently. The inventors have found that sufficient strength can be imparted, and have come up with the idea that the above problems can be solved brilliantly. In addition, it has been found that such a fluidity reducing agent is excellent in storage stability and safety, and has reached the present invention.

That is, the present invention is a fluidity lowering agent for hydrous soil comprising a water-soluble polymer (P), wherein the water-soluble polymer (P) is a (meth) acrylic acid (salt) monomer (A 20-99 mol%, the following general formula (1);
^{_{CH 2 = C (R) -COOZ}} 1 (O) p Z 2 OX (1)
(In the formula, R represents a hydrogen atom or a methyl group. Z ¹ and Z ² are the same or different and represent an alkylene group having 8 or less carbon atoms. X represents a hydrocarbon group having 4 or less carbon atoms. P represents an integer of 0 or 1.) The (meth) acrylate monomer (B) represented by 1 to 80 mol%, and the monomers (A) and (B) A fluidity reducing agent obtained by polymerizing 100 mol% of a monomer component containing 0 to 30 mol% of another copolymerizable monomer (C) and having a weight average molecular weight of 500,000 or more. is there.
The present invention is also a method for treating hydrous soil using the fluidity reducing agent. Specifically, it is a granulated treatment or granulated solidification method of hydrous soil.
The present invention is described in detail below.

The fluidity reducing agent of the present invention comprises (meth) acrylic acid (salt) monomer (A) and the following general formula (1); CH ₂ ═C (R) —COOZ ¹ (O) _p Z ² OX (1 )
(In the formula, R represents a hydrogen atom or a methyl group. Z ¹ and Z ² are the same or different and represent an alkylene group having 8 or less carbon atoms. X represents a hydrocarbon group having 4 or less carbon atoms. P represents an integer of 0 or 1.) A water-soluble polymer (P) obtained by polymerizing a monomer component essentially comprising a (meth) acrylic acid ester monomer (B) represented by ). Such a fluidity reducing agent is generally used in the form of powder, but may be in any form such as powder, liquid or gel, and is not particularly limited. Among these, it is preferable to use the powdery form in consideration of the cost during transportation. In the water-soluble polymer (P), the (meth) acrylic acid (salt) monomer (A) and the (meth) acrylic acid ester monomer (B) are each one or two types. The above can be used together.

In the water-soluble polymer (P), the (meth) acrylic acid (salt) monomer (A) is (meth) acrylic acid and / or (meth) acrylate, but (meth) acrylic acid. As the salt, neutralized product obtained by neutralizing (meth) acrylic acid with monovalent metal, divalent metal, ammonia, organic amine, etc., that is, sodium (meth) acrylate, potassium (meth) acrylate, (meth ) Magnesium acrylate, calcium (meth) acrylate, ammonium (meth) acrylate, and the like are suitable. Among these, sodium (meth) acrylate is preferable, and sodium acrylate is more preferable.

In the (meth) acrylic acid ester monomer (B) represented by the general formula (1), R represents a hydrogen atom or a methyl group. Z ¹ and Z ² are the same or different and represent an alkylene group having 8 or less carbon atoms, and for example, a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and the like are preferable. X represents a hydrocarbon group having 4 or less carbon atoms. For example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group and the like are preferable. p represents an integer of 0 or 1.
Examples of such (meth) acrylic acid ester monomers (B) include methoxyethyl (meth) acrylate, methoxyethyloxyethyl (meth) acrylate, methoxypropyl (meth) acrylate, and methoxybutyl (meth) acrylate. Methoxyethyloxybutyl (meth) acrylate, ethoxyethyl (meth) acrylate, ethoxyethyloxyethyl (meth) acrylate, propoxypropyl (meth) acrylate, propoxybutyl (meth) acrylate and the like are suitable. Among these, methoxyethyl (meth) acrylate is preferable. More preferably, it is methoxyethyl acrylate (methoxyethyl acrylate), and the form in which the (meth) acrylic acid ester monomer (B) is methoxyethyl acrylate is one of the preferred forms of the present invention. .

In the water-soluble polymer (P), in addition to the (meth) acrylic acid (salt) monomer (A) and the (meth) acrylic acid ester monomer (B), these monomers You may use the other monomer (C) copolymerizable with the. The monomer (C) is not particularly limited as long as the resulting water-soluble polymer (P) becomes water-soluble, and examples thereof include the following.
unsaturated monocarboxylic acid monomers such as α-hydroxyacrylic acid, crotonic acid and their monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts (organic ammonium salts); maleic acid, fumaric acid, Unsaturated dicarboxylic acid monomers such as itaconic acid, citraconic acid and their monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts; vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfone Acid, 2-acrylamido-2-methylpropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, sulfoethyl (meth) acrylate, sulfopropyl (meth) acrylate, 2-hydroxysulfopropyl (meth) acrylate, sulfoethylmaleimide And their monovalent metal salts, divalent metal salts, ammonium salts Unsaturated sulfonic acid monomers such as organic amine salts; (meth) acrylamide methanephosphonic acid, 2- (meth) acrylamide-2-methylpropanephosphonic acid and their monovalent metal salts, divalent metal salts, ammonium salts Unsaturated phosphonic monomers such as organic amine salts; amide monomers such as (meth) acrylamide and t-butyl (meth) acrylamide; 3-methyl-2-buten-1-ol (prenol), 3-methyl-3-buten-1-ol (isoprenol), 2-methyl-3-buten-2-ol (isoprene alcohol), 2-hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol Mono (meth) acrylate, polyethylene glycol monoisoprenol ether, poly Unsaturated monomers having hydroxyl groups such as propylene glycol monoisoprenol ether, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, glycerol monoallyl ether, N-methylol (meth) acrylamide, glycerol mono (meth) acrylate, vinyl alcohol Bodies; alkoxyalkylene glycol mono (meth) acrylates such as methoxypolyethylene glycol mono (meth) acrylate; cationic monomers such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate; and (meth) acrylonitrile Nitrile monomers; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, styrene, 2-methylstyrene, acetic acid Can be mentioned hydrophobic monomer sulfonyl like, can be used alone or in combination of two or more thereof.

As a content ratio in the monomer components of the monomers (A) to (C), assuming that the total amount of the monomer components used for polymerization is 100 mol%, (meth) acrylic acid (salt) single amount The body (A) is 20 to 99 mol%, the (meth) acrylic acid ester monomer (B) is 1 to 80 mol%, and the other copolymerizable monomer (C) is 0 to 30 mol%. It is appropriate to be. If the content ratio of the (meth) acrylic acid (salt) monomer (A) is too higher than the above range, that is, the use ratio of the (meth) acrylic acid ester monomer (B) is within the above range. Even if there is contact with groundwater or seawater containing a large amount of polyvalent metal ions such as calcium ions and magnesium ions, the fluidity of the hydrous soil can be sufficiently reduced. On the contrary, when the water-soluble polymer (P) having the above-mentioned monomer composition ratio is used, it can be used not only for groundwater but also for water with high salt concentration such as waste water and seawater as industrial water quality. The utility value is extremely high. Preferably, the content ratio of the (meth) acrylic acid ester monomer (B) is 5 to 50 mol%, and such a form is also a preferred form of the present invention. . More preferably, (A) is 40 to 95 mol%, (B) is 5 to 50 mol%, (C) is 0 to 15 mol%, and more preferably (A) is 60 to 90 mol%, (B) is 10 to 40 mol%, and (C) is 0 to 10 mol%.

As a preferred form of the water-soluble polymer (P), when the total amount of polymerizable monomers used in the polymerization is 100 mol%, the (meth) acrylic acid (salt) monomer (A) and The total amount (total mol%) with the (meth) acrylic acid ester monomer (B) is 70 mol% or more. As described above, the water-soluble polymer (P) is a single amount in which the monomer (B) represented by methoxyethyl acrylate and the monomer (A) represented by acrylic acid are used in a large amount. By being a polymer obtained from the body composition, it becomes a fluidity reducing agent that can sufficiently exhibit the salt resistance and fluidity reduction effects. Specifically, in addition to the salt resistance and fluidity lowering effects, the viscosity, water stoppage, and lubricity become better. More preferably, the total mol% is 75 mol% or more, more preferably 80 mol% or more, particularly preferably 85 mol% or more, and most preferably 90 mol% or more.

The weight average molecular weight of the water-soluble polymer (P) in the present invention is 500,000 or more. If it is less than 500,000, the improved hydrous soil may not be sufficiently granulated. Preferably, it is 700,000 or more, more preferably 800,000 or more, and still more preferably 1,000,000 or more. Thus, the larger the weight average molecular weight, the more the amount of water-soluble polymer (P) used for granulation can be sufficiently reduced. Moreover, if the usage-amount of water-soluble polymer (P) is equal, regulation of the water-containing soil (solidified material of water-containing soil) after improvement will be specified, so that the weight average molecular weight of water-soluble polymer (P) is large. It is possible to reduce the particle size (reducing the particle size) within a range not corresponding to the above. On the other hand, the upper limit of the weight average molecular weight is preferably 7 million. If it exceeds 7 million, the dissolution rate in water may not be sufficient, and when such a water-soluble polymer (P) is mixed with water-containing soil, a thickening effect occurs and both are mixed uniformly. There is a possibility that the effects of the present invention cannot be fully exhibited. Moreover, there is a possibility that insoluble matter described later also increases. A more preferable upper limit is 5 million. The weight average molecular weight can be measured by a light scattering method.

The water-soluble polymer (P) is preferably used as a powder after being obtained by polymerization and then undergoing a predetermined drying step and pulverization step. In addition, the drying method and the pulverization method are not particularly limited, and the polymerization method is as described later.
When the water-soluble polymer (P) is used as a powder, the particle size of the polymer is preferably in the range of 50 to 2000 μm. If it exceeds 2000 μm, it is necessary to increase the amount of the water-soluble polymer (P) necessary for refining the granulated (granulated) hydrous soil after improvement, that is, hydrous soil, and economically May be disadvantageous. When it is less than 50 μm, dust is likely to be generated when the water-soluble polymer (P) is handled, and the water-soluble polymer (P) may easily absorb moisture, and as a result, workability is sufficient. In addition, when added to hydrous soil, spalling occurs. For this reason, in order to refine | solidify the solidified material of a hydrous soil, it is necessary to increase the usage-amount, and also in this case, there exists a possibility that it may become economically disadvantageous. More preferably, it exists in the range of 100-1000 micrometers.
The particle diameter of the water-soluble polymer (P) means an average particle diameter, and the dry powder produced through a predetermined drying step and pulverization step is used to determine the particle size distribution using a JIS sieve. It can be measured and further calculated by a weighted average method.

In obtaining a water-soluble polymer (P) having a large weight average molecular weight, the insoluble content may increase during polymerization or drying. The insoluble content of the water-soluble polymer (P) used in the present invention is preferably 5% by mass or less, and thus the insoluble content of the water-soluble polymer (P) is 5% by mass or less. The form is also one of the preferred forms of the present invention. Specifically, if the insoluble content is 5% by mass or less, the fluidity of the water-containing soil can be sufficiently lowered, and further physical properties such as viscosity, water-stopping property, and lubricity are further improved. However, if the insoluble content exceeds 5% by mass, the effects of the present invention may not be sufficiently exhibited. More preferably, it is 4 mass% or less, More preferably, it is 3 mass% or less, More preferably, it is 2 mass% or less, Especially preferably, it is 1 mass% or less, Most preferably, it is 0 .5% by mass or less.
In order to reduce the insoluble content to 5% by mass or less, it is preferable to control the polymerization reaction so as to lower the peak exothermic temperature during the polymerization reaction and / or use a chain transfer agent during the polymerization. It becomes.

The insoluble matter can be measured as follows.
(Measurement method of insoluble matter)
In a beaker having a capacity of 500 ml, 500 g of ion exchange water is added, and 1.0 g of a sufficiently dried water-soluble polymer (P) is added to the ion exchange water while stirring using a magnetic stirrer. Next, this mixture is stirred (100 rpm) at 25 ° C. for 2 hours using a jar tester, and then filtered using a 32 mesh filter to take out water-containing insoluble matter. Then, this insoluble matter is weighed immediately (within 1 minute) so as not to dry, and the insoluble matter is calculated based on the following formula. The filtration and weighing are performed at 25 ° C. and a relative humidity of 60%.
Insoluble matter (mass%) = {mass of insoluble matter (g) / 500 (g)} × 100

The neutralization degree of the water-soluble polymer (P) is preferably 10% or more and 100% or less. More preferably, it is 20% or more and 70% or less. The degree of neutralization is the content ratio of the neutralized group, and the neutralization when the sum of the acid group of the polymer and the neutralized group is shown as 100 mol%. It means the content of the group in the state.
The content ratio of the group in the neutralized form can be determined as follows.
(Neutralized group content)
For example, the monomer component used to produce the polymer corresponds to x mol of acrylic acid, y mol of sodium acrylate as an acrylate salt, and general formula (1) as an acrylic ester monomer. Assuming that the monomer, methoxyethyl acrylate, contains z moles and these are all polymerized, the acrylic ester monomer is not ionic and is not in a neutralized form. It will be required. In the denominator, the sum of the number of moles of the monomer having an acid group and the monomer having a neutralized group (here, a salt form in which an acid group is neutralized with an alkali metal or the like) is taken. The molecule takes the number of moles of a monomer having a neutralized group (here, a salt form in which an acid group is neutralized with an alkali metal or the like). By applying this to the following formula, the content ratio of the neutralized group is calculated as a percentage, and the unit is mol%.

As the method for producing the water-soluble polymer (P) of the present invention, various polymerization methods such as a reverse phase suspension polymerization method and a solution polymerization method can be used, and the solution polymerization method is not particularly limited. Is preferred. More preferred is a method of polymerizing by standing polymerization in an aqueous solution, and such a method is preferred because a water-soluble polymer having a small amount of insolubles and a high molecular weight can be easily produced. Moreover, as a polymerization form, a cast polymerization method or a belt polymerization method can be employed. The monomer concentration during polymerization is preferably 30 to 90% by mass. More preferably, it is 35-70 mass%, More preferably, it is 40-60 mass%.

As the above polymerization method, either thermal polymerization or photopolymerization can be produced, but a photopolymerization method is more preferable because a polymer having a small insoluble content and a large weight average molecular weight can be easily obtained.
Examples of the polymerization initiator in the case of the thermal polymerization include hydrogen peroxide; persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; 2,2′-azobis- (2-amidinopropane) dihydrochloride. Water-soluble radical polymerization initiators such as azo compounds such as 2,2′-azobis- [2- (2-imidazolin) -2-yl] propane] dihydrochloride, and the like. Can be used. Among these thermal polymerization initiators, azo compounds are particularly preferable.
The amount of the thermal polymerization initiator used is preferably in the range of 0.0001 to 0.05 g with respect to 1 mol of the monomer component. As a polymerization start temperature at the time of thermal polymerization, 15 to 50 ° C. is preferable. It is preferable to control the polymerization so that the maximum temperature of the reaction liquid at the time of polymerization is 150 ° C. or lower, preferably 120 ° C. or lower, more preferably 110 ° C. or lower.

As the polymerization initiator in the case of the photopolymerization, the following compounds can be used.
2,2'-azobis (2-amidinopropane), 2,2'-azobis (N, N'-dimethyleneisobutylamidine), 2,2'-azobis [2- (5-methyl-2-imidazoline-2 -Yl) propane], 1,1'-azobis (1-amidino-1-cyclopropylethane), 2,2'-azobis (2-amidino-4-methylpentane), 2,2'-azobis (2- N-phenylaminoamidinopropane), 2,2′-azobis (1-imino-1-ethylamino-2-methylpropane), 2,2′-azobis (1-allylamino-1-imino-2-methylbutane), 2,2'-azobis (2-N-cyclohexylamidinopropane), 2,2'-azobis (2-N-benzylamidinopropane) and its hydrochloric acid, sulfuric acid, acetate, etc., 4,4'-azo (4-cyanovaleric acid) and its alkali metal salts, ammonium salts, amine salts, 2- (carbamoylazo) isobutyronitrile, 2,2'-azobis (isobutyramide), 2,2'-azobis [2 -Methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis [2-methyl-N- (1,1'-bis (hydroxymethyl) ethyl) propionamide], 2,2'- An azo photopolymerization initiator such as azobis [2-methyl-N-1,1′-bis (hydroxyethyl) propionamide].

2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxy-cyclohexyl A eutectic mixture of phenyl-ketone (Irgacure 184) and benzophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl -1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-benzyl-2- Dimethylamino-1- (4-morpholinophenyl) -butanone-1 (Irgacure 369) and 2,2-dimethoxy-1,2 3: 7 mixture with diphenylethane-1-one (Irgacure 651), bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4 -1: 3 mixture of trimethyl-pentylphosphine oxide (CGI403) and 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur 1173), bis (2,6-dimethoxybenzoyl)- A 1: 3 mixture of 2,4,4-trimethyl-pentylphosphine oxide (CGI 403) and 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184), bis (2,6-dimethoxybenzoyl) -2,4 , 4-trimethyl-pentylphosphine oxide (CGI403) and 1: 1 mixture with -hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propane-1 -1: 1 liquid mixture with ONE (Darocur 1173), bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) ) -Phenyl) titanium, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone], eutectic mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzophenone Liquid mixture of 4-methylbenzophenone and benzophenone, 2,4,6-trimethylbenzoyldiphenyl O scan fins oxide and oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] and the liquid mixture of methyl benzophenone derivatives.

1- [4- (4-Benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methylphenylsulfanyl) propan-1-one, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenyl- 1-propanone, α-hydroxycyclohexyl-phenyl ketone, ethyl 4-dimethylaminobenzoate, acrylated amine synergist, benzoin (iso- and n-) butyl ester, acrylic sulfonium (mono, di) hexafluorophosphate, 2 -Isopropylthioxanthone, 4-benzoyl-4'-methyldiphenyl sulfide, 2-butoxyethyl 4- (dimethylamino) benzoate, ethyl 4- (dimethylamino) benzoate, benzoin, benzoin alkyl ether, benzoin hydroxy Ruki ether, diacetyl and its derivatives, anthraquinone and its derivatives, diphenyl disulfide and its derivatives, benzophenone and its derivatives, benzyl and its derivatives.

The amount of the photopolymerization initiator used is preferably 0.0001 g or more and more preferably 1 g or less with respect to 1 mol of the monomer component used for polymerization. Thereby, the weight average molecular weight and polymerization rate of water-soluble polymer (P) can be made high enough. More preferably, it is 0.001 g or more and 0.5 g or less. The polymerization initiation temperature for photopolymerization is preferably 0 to 30 ° C. The polymerization is preferably controlled so that the maximum temperature of the reaction solution during the polymerization is 150 ° C. or lower, preferably 120 ° C., more preferably 110 ° C. or lower.

When carrying out the photopolymerization, it is preferable to irradiate the reaction solution or the like with near ultraviolet rays. For example, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a fluorescent chemical lamp, or a fluorescent blue lamp is suitable as a device that irradiates near ultraviolet rays. Further, the wavelength region of near ultraviolet rays is preferably 300 nm or more, and preferably 500 nm or less. By irradiating the reaction liquid or the like with ultraviolet rays having a wavelength in this range, photopolymerization starts and the polymerization reaction proceeds at an appropriate rate. Moreover, when performing photopolymerization, it is preferable to superpose | polymerize by irradiating near ultraviolet rays with the intensity | strength of 0.1-100 W / m < ² >, and, thereby, an insoluble part can be decreased more.

In order to obtain the water-soluble polymer (P) of the present invention, it is preferable to use a chain transfer agent together with the above polymerization initiator. By using an appropriate amount of the chain transfer agent, it is possible to produce a polymer in which the water-soluble polymer (P) has a higher weight average molecular weight and less insoluble matter. As a result, when the water-soluble polymer (P) is used as a fluidity-reducing agent, it can be a fluidity-reducing agent with excellent salt resistance and can sufficiently exhibit the fluidity-reducing effect of hydrous soil. It becomes. Moreover, physical properties such as viscosity, water-stopping property and lubricity of the hydrous soil are further improved.
Examples of the chain transfer agent include sulfur-containing compounds such as thioglycolic acid, thioacetic acid, and mercaptoethanol; phosphorous compounds such as phosphorous acid and sodium phosphite; hypophosphorous acid such as hypophosphorous acid and sodium hypophosphite Preferred compounds are alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and n-butyl alcohol. Among these, hypophosphorous acid compounds are preferable. More preferred is sodium hypophosphite.
The amount of the chain transfer agent used may be appropriately set depending on the polymerization concentration, a combination with a photopolymerization initiator, and the like, but is preferably 0.0001 g or more with respect to 1 mol of the monomer component used for the polymerization. Moreover, 0.2 g or less is preferable. Further, it is more preferably 0.001 g or more and 0.15 g or less, and particularly preferably 0.005 g or more and 0.10 g or less.

The fluidity reducing agent of the present invention contains the above water-soluble polymer (P) as an essential component, and further contains at least one component of a superabsorbent resin, a clay mineral and an aluminate. Is preferred. Hereinafter, these will be described.
[Superabsorbent resin]
In order to further increase the performance as a fluidity reducing agent, it is preferable to add and use a superabsorbent resin in combination with the fluidity reducing agent according to the present invention. By blending a highly water-absorbing resin with the fluidity reducing agent having excellent salt resistance of the present invention, the friction reducing property, water-stopping property, lubricity and the like are further imparted. Become. Examples of such a highly water-absorbing resin include a crosslinked polyacrylate, a crosslinked acrylic acid-acrylic acid ester copolymer, a crosslinked isobutylene-maleic anhydride copolymer, and a crosslinked carboxylic acid. Other than modified polyvinyl alcohol, cross-linked acrylic acid-acrylamide copolymer, cross-linked acrylic acid-sulfoethyl acrylate copolymer, cross-linked acrylic acid-2 acrylamide-2-methylpropane sulfonic acid copolymer, etc. Saponified vinyl acetate-acrylic acid ester copolymer, vinyl acetate-maleic acid copolymer, isobutylene-methyl maleic anhydride copolymer, hydrolyzed polyacrylonitrile, starch-saponified acrylonitrile-graft polymer, starch- Acrylic acid graft polymer, polysaccharide-acrylic acid graft polymer PVA crosslinked product, a polyester oxide crosslinked product, etc., can be used alone or in combination of two or more thereof. These highly water-absorbent resins preferably have a water absorption rate of 50 to 1000 g / g per gram as a water absorption rate with respect to pure water and 5 to 50 g / g as a water absorption rate with respect to artificial seawater. The water absorption magnification can be measured using the following tea bag method. As the particle shape, either spherical or indefinite shape can be used. As an average particle diameter, it is 50-450 micrometers, More preferably, it is 100-400 micrometers. The amount of the superabsorbent resin used is preferably 5 to 2000 parts by weight with respect to 100 parts by weight of the water-soluble polymer (P).
Further, the surface of the superabsorbent resin may be cross-linked by thermal crosslinking, epoxy, glycol or the like, if necessary. Further, the surface thereof may be coated or modified with a thermoplastic resin or an inorganic compound.

(Measurement method of water absorption magnification-tea bag method-)
After 0.2 g of polymer crosslinked particles are uniformly placed in a non-woven tea bag bag (40 mm × 150 mm) and immersed in deionized water (pure water) for 1 hour, the bag is pulled up and drained for 10 minutes. The mass can be measured, and the water absorption magnification can be calculated by the following formula. In addition, a blank is a mass when the same operation is performed only with a tea bag type bag. Further, the water absorption ratio with respect to artificial seawater can be calculated by the tea bag method using artificial seawater instead of deionized water. In addition, the artificial seawater is prepared by dissolving one bag for artificial seawater 25L (for example, artificial seawater, Aquamarine (registered trademark) manufactured by Yasu Pharmaceutical Co., Ltd.) in 25L of water. be able to.

[Clay mineral]
In order to further increase the performance as a fluidity reducing agent, it is preferable to add and use a clay mineral together with the fluidity reducing agent according to the present invention. Examples of the clay mineral include sepiolite, attapulgite, entry guide, bentonite, kaolin clay, montmorillonite, ectolite, saponite, beidellite, zeolite, palygorskalite, mica, and the like, one or two of these. The above can be used. Among these, at least one selected from sepiolite, attapulgite, entry guide, bentonite, and kaolin clay is preferable. The amount of the clay mineral used is preferably 5 to 500 parts by weight with respect to 100 parts by weight of the water-soluble polymer (P).

[Aluminate]
In order to increase the performance as a fluidity lowering agent to the fluidity lowering agent according to the present invention, in particular, since seawater resistance can be further improved, it is preferable to add and use an aluminate in combination. The aluminate is preferably a monovalent metal of aluminate, such as alkali metal aluminate such as sodium aluminate and potassium aluminate, ammonium salt, monoethanolamine aluminate, diethanolamine aluminate, trialuminate trialuminate. Examples thereof include alkanolamine salts of aluminates such as ethanolamine salts and alkyl (C ₁ -C ₄ ) amine salts. Among these, sodium aluminate is particularly preferable. The amount of the aluminate used is preferably 5 to 300 parts by weight with respect to 100 parts by weight of the water-soluble polymer (P).

Moreover, the fluidity reducing agent according to the present invention may contain an antifoaming agent, if necessary. By adding the antifoaming agent, foam generated during use of the mudifying agent is suppressed. This makes it easy to handle the mudifier. Therefore, it is preferable to use together with a fluidity reducing agent. Examples of the antifoaming agent include a silicone-based antifoaming agent, a prolunic antifoaming agent, and a mineral-based antifoaming agent.

When using the fluidity reducing agent of the present invention, other water-soluble polymers and water-soluble natural polymer compounds can be used in combination as long as the effects of the present invention are not impaired. Examples of the water-soluble polymer include polyacrylic acid, polyvinyl alcohol, an acrylamide polymer that may have a sulfonic acid group, an isobutylene-maleic anhydride copolymer, polyethyleneimine, polyalkylamine, and the like. And complex compounds. Examples of the water-soluble natural polymer compound include carboxymethyl cellulose or a salt thereof, xanthan gum, sodium alginate, starch and the like. In addition, an inorganic compound such as a calcium compound can be blended as a gelling agent or a flocculant into the water-containing soil blended with the fluidity reducing agent of the present invention to further synergize the effects of the present invention.
In addition, a dry powder of the fluidity reducing agent of the present invention, and a powder selected from water-absorbing resin, clay mineral and other additive powders blended as necessary, are mixed into a packaging material such as paper or film. Or it may be packaged with a water-soluble film and used on site. If the water-soluble film is formed of a polyvinyl alcohol-based resin, it is convenient because the water-soluble film acts as a thickener even when used in the form of packaging on site.

As the fluidity reducing agent of the present invention, it is possible to improve the water-containing soil that is usually discarded as sludge by having the above-described configuration, that is, it can be transported by truck and a person can walk on it. The solidified product in a state can be obtained, and further, the solidified product finely divided into particles having sufficient strength and a predetermined particle diameter can be obtained. Thereby, the hydrous soil after improvement can be effectively utilized for backfilling, agricultural or horticultural use, for example, as a substitute for sand, or reused as a resource. Moreover, if the hydrous soil after improvement is made into a granular solidified material, the water permeability when backfilled on the ground can be improved, and the hydrous soil can be reused in a wider range. As a result, environmental conservation, resource saving, and life extension of the disposal site can be achieved, and disposal costs for hydrous soil can be reduced. Such a method for improving hydrous soil, that is, a method for treating hydrous soil using the fluidity reducing agent is also one aspect of the present invention.

The water-containing soil that is the subject of the present invention is not particularly limited, and may be a form containing bentonite in addition to clay and silt that have been difficult to reuse in the past. By adding the fluidity reducing agent of the present invention to such a water-containing soil, as an improved soil, for example, a construction defined in the “Construction Soil Utilization Technology Manual” (1994, published by the Civil Engineering Research Center) It can be a solidified product not corresponding to sludge. That is, a solidified product that can be transported by truck and can be walked on by a person, and is further solidified into particles having sufficient strength and a predetermined particle diameter. Is possible.
As the above water-containing soil, for example, the generated soil generated during excavation in the excavation work adopting the underground continuous wall construction method, cast-in-place pile construction method, etc. is separated into earth and sand and muddy water, and the muddy water is dehydrated and pressed. Sludge obtained as a dehydrated cake after solid-liquid separation; sludge generated from the mud shield method; sludge generated as a result of standing in the sedimentation tank after the construction work; sludge obtained as sediment; Residual soil; sludge such as hydrated stone powder generated at quarries and quarries.

As a preferable form of the water-containing soil, a form in which the water content ratio [(water (g) / solid content (g)) × 100] measured by JIS A1203 (water content ratio test method) is 20 to 200% is preferable. Since the water-containing soil exceeding 200% has a high water content (hereinafter also referred to as “water content”), it is necessary to use a large amount of fluidity reducing agent, which may increase the cost of the fluidity reducing agent. There is. More preferably, it is a form which is 40 to 180%.

Next, a method for improving water-containing soil using the fluidity reducing agent of the present invention will be described below.
First, the fluidity reducing agent and the water-containing soil are mixed. As a mixer used for mixing these, an apparatus capable of stirring and mixing without kneading the mixture of both is preferable. A device that is a so-called planetary motion type or biaxial type, and in which the shape of the stirring blade is formed in a rod shape or a fishhook shape so that stirring can be performed while applying a shearing force to the mixture of both. Is preferred. That is, the stirring blade preferably has a shape that expands in a direction as perpendicular as possible to the moving direction of the mixture that moves by stirring and mixing, thereby suppressing the coarsening of the particle diameter due to kneading, and the stirring blade and device. Adhesion of the mixture to the inner wall can be prevented.

Examples of such an apparatus include a horizontal shaft type mixer and a vertical shaft type mixer. As the horizontal axis type mixer, for example, a single-axis and multi-axis paddle type mixer is preferable. As the vertical shaft type mixer, for example, a pan mixer type mixer is preferable. A planetary mixer is more preferable, and among them, a soil mixer, a mortar mixer, and an Eirich mixer are preferable. Using these mixers, the fluidity reducing agent and the hydrous soil are mixed, and by using the shearing force generated by the stirring blade, the mixture is formed into particles having a particle diameter in the range of 0.1 to 50 mm. Fine graining (granular solidification, granulation) can be performed. Preferably, it is within a range of 0.3 to 10 mm.

The mixing method of the fluidity reducing agent and the hydrous soil is not particularly limited, but the usage amount of the fluidity reducing agent is such that the usage amount of the water-soluble polymer (P) with respect to 100 parts by weight of the hydrous soil is 0.01. It is preferable to set it to be in the range of ˜5 parts by weight. If it is less than 0.01 part by weight, the solidified product of the hydrous soil may not be sufficiently finely divided. Moreover, even if it exceeds 5 weight part, there is a possibility that the water-soluble polymer (P) used excessively will be wasted, and an effect will hardly change with the case where it uses within the said range. More preferably, it is in the range of 0.01 to 1 part by weight. In addition, when using water-soluble polymer (P) in the state of aqueous solution, the usage-amount of the said water-soluble polymer (P) shall show the quantity (pure part) of this polymer in aqueous solution.
Thus, the method of processing by using 0.01 to 5 parts by weight of the water-soluble polymer (P) as a fluidity reducing agent with respect to 100 parts by weight of the hydrous soil is also a preferred embodiment of the present invention. One.

Then, if necessary, it is preferable to add and mix a hydraulic substance to the obtained improved soil (granular solidified product), so that sufficient granulation and sufficient strength can be imparted. It becomes. That is, the method for treating hydrous soil using a hydraulic substance is a more preferable embodiment of the present invention. In order to sufficiently solidify the water-containing soil, a mode in which the hydraulic substance is mixed after the fluidity reducing agent is mixed with the water-containing soil is preferable.
In the present invention, it is more preferable to add a fluidity reducing agent to the water-containing soil to reduce the fluidity of the water-containing soil and to granulate the water-containing soil.
The hydraulic substance is not particularly limited as long as it cures in water, and examples thereof include cement, quicklime, slaked lime, gypsum, and mixtures thereof. Of these, cement and quicklime are preferred.
As the cement, various known cements can be used, for example, Portland cement such as ordinary Portland cement, early-strength Portland cement, and ultra-early-strength Portland cement; blast furnace cement; alumina cement; calcium cement; fly ash cement and the like. Although it is mentioned, it is not particularly limited.
Since the polymer of the present invention (water-soluble polymer (P)) has salt resistance, as described above, even in a state where a hydraulic substance is blended, the aggregation performance of the polymer does not deteriorate, so the above is effective. Sufficient strength can be imparted to the granular solidified product.

Although the mixer used when mixing a hydraulic substance with improved soil (granular solidified material) is not specifically limited, The apparatus which can be stirred and mixed without knead | mixing both mixtures is suitable. is there. Moreover, when mixing using such a mixer, the shearing force is not applied as much as when mixing the above-mentioned water-containing soil and the fluidity reducing agent, and the surface of the improved soil (granular solidified product) is hydraulic. It is preferable to stir so that the substance adheres. Thereby, the improved soil (granular solidified product) in which the hydraulic substance adheres almost uniformly to the surface of the improved soil (granular solidified product) is obtained. A part of the hydraulic substance may enter the inside of the improved soil (granular solidified product).
Here, although the mixing method of improved soil (granular solidified material) and a hydraulic substance is not specifically limited, As usage-amount of a hydraulic substance, it shall be 1-35 weight part with respect to 100 weight part of hydrous soil. Is preferred. If it is less than 1 part by weight, the strength of the improved soil (granular solidified product) may not be sufficient, and even if it exceeds 35 parts by weight, the effect is almost the same as when used within the above range, and it is excessive. There is a risk that the polymer used in the process will be wasted. More preferably, it exists in the range of 1-20 weight part, More preferably, it exists in the range of 1-10 weight part.
The improved soil (granular solidified product) thus obtained may be immediately backfilled, but may be left at room temperature for about 3 to 7 days, and the hydraulic material is cured and sufficient. Can be provided with sufficient strength.

The improved soil obtained as described above can be transported by truck. For example, it is a solidified material that has been improved so that a person can walk on it, more preferably a granular solidified material. It does not fall under the category and can be reused. In particular, since the solidified solid has a predetermined particle diameter and strength, it can be reused as a resource such as a sand substitute without performing operations such as pulverization and sieving. That is, in civil engineering work that requires backfilling of excavation holes, it is possible to backfill using this granular solidified material without preparing sand or the like separately. Moreover, since the said granular solidified material can improve the water permeability at the time of refilling on the ground, reuse of a hydrous soil in a wider range is attained. Therefore, as the improved soil, for example, a backfill material used when backfilling buried pipes or structures, a barrier layer material as artificial sand, a vegetation base material that blows on a slope surface and processes the slope surface, soil It can be suitably used for an improving material, a water retaining material, a water permeable material, a water quality improving material and the like.

Since the fluidity reducing agent of the present invention is configured as described above, the fluidity reducing agent is excellent in salt resistance and seawater resistance, and can sufficiently reduce the fluidity of the hydrous soil, thereby efficiently improving the hydrous soil. This makes it possible to reuse the water-containing soil that is normally discarded as sludge, to preserve the environment, conserve resources, extend the life of the disposal site, and reduce the disposal cost of the water-containing soil. It becomes possible.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

In addition, the weight average molecular weight of the polymer is measured under the following conditions using a dynamic light scattering photometer.
Apparatus: Dynamic light scattering photometer (trade name “DSL-700” manufactured by Otsuka Electronics Co., Ltd.)
Solvent: 0.16 M / L NaCl aqueous solution Sample concentration: 0.05-2 mg / ml
Sample pH: 10 (at 25 ° C)
Measurement temperature: 25 ° C
The average particle size of the polymer dry powder is determined by measuring the particle size distribution using a JIS sieve with respect to the polymer obtained after performing the predetermined pulverization step, and by the weighted average method. Calculated.

Synthesis example 1
In a 500 ml beaker, 17.08 g of acrylic acid, 27.66 g of 37% aqueous solution of sodium acrylate, 31.46 g of methoxyethyl acrylate, and 71.38 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Then, while stirring, 1.21 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.06 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator. 1.21 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 42 mol% acrylic acid, 18 mol% sodium acrylate, and 40 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Subsequently, it grind | pulverizes using a table-type grinder, and the water-soluble polymer (1) of acrylic acid / sodium acrylate / methoxyethyl acrylate = 42/18/40 molar ratio and the neutralization degree is 30 mol% according to the present invention. ) The water-soluble polymer (1) had a weight average molecular weight of 1,450,000 and an insoluble content of 0.03%. The weight average molecular weight is a molecular weight measured by the above light scattering method. The average particle size of the dry polymer powder was 150 μm.

Synthesis example 2
In a beaker having a capacity of 500 ml, 35.71 g of acrylic acid, 56.28 g of a 37% aqueous solution of sodium acrylate, 1.96 g of methoxyethyl acrylate and 53.03 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, 1.51 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.06 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator while stirring. 1.51 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 68.6 mol% acrylic acid, 29.4 mol% sodium acrylate, and 2.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, A neutralization degree is 30 mol with acrylic acid / sodium acrylate / methoxyethyl acrylate = 68.6 / 29.4 / 2.0 (molar ratio) according to the present invention. % Water-soluble polymer (2) was obtained. The water-soluble polymer (2) had a weight average molecular weight of 16.3 million and an insoluble content of 0.06%. The weight average molecular weight is a molecular weight measured by the above light scattering method. The average particle size of the polymer dry powder is shown in Table 1. The polymers in Synthesis Examples 3 to 10 are also shown in Table 1.

Synthesis example 3
In a 500 ml beaker, 5.43 g of acrylic acid, 9.75 g of a 37% aqueous solution of sodium acrylate, 49.94 g of methoxyethyl acrylate, and 82.84 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, while stirring, 1.02 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.06 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator. 1.02 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 17.5 mol% acrylic acid, 7.5 mol% sodium acrylate, and 75.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, A neutralization degree is 30 mol with acrylic acid / sodium acrylate / methoxyethyl acrylate = 17.5 / 7.5 / 75.0 (molar ratio) according to the present invention. % Water-soluble polymer (3) was obtained. The water-soluble polymer (3) had a weight average molecular weight of 1,540,000 and an insoluble content of 0.21%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Synthesis example 4
In a beaker having a capacity of 500 ml, 12.56 g of acrylic acid, 27.29 g of a 37% aqueous solution of sodium acrylate, 5.13 g of methacrylic acid, 31.02 g of methoxyethyl acrylate, and 71.62 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, while stirring, 1.19 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.06 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator. 1.19 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 32.0 mol% acrylic acid, 18.0 mol% sodium acrylate, 10.0 mol% methacrylic acid, and 40.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 60 minutes at a light intensity of 22 W / m ² using near ultraviolet rays (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started about 15 minutes after the start of irradiation. Irradiation was continued for 60 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, Acrylic acid / Sodium acrylate / Methacrylic acid / Methoxyethyl acrylate according to the present invention = 32.0 / 18.0 / 10.0 / 40.0 (molar ratio) Thus, a water-soluble polymer (4) having a neutralization degree of 30 mol% was obtained. The water-soluble polymer (4) had a weight average molecular weight of 1,660,000 and an insoluble content of 1.21%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Synthesis example 5
In a 500 ml beaker, 17.08 g of acrylic acid, 27.66 g of a 37% aqueous solution of sodium acrylate, 31.46 g of methoxyethyl acrylate, and 70.88 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Then, while stirring, 1.71 g of a sodium hypophosphite 6.0% aqueous solution as a chain transfer agent (0.17 g based on 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator. 1.21 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 42.0 mol% acrylic acid, 18.0 mol% sodium acrylate, and 40.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, A neutralization degree is 30 mol with acrylic acid / sodium acrylate / methoxyethyl acrylate = 42.0 / 18.0 / 40.0 (molar ratio) according to the present invention. % Water-soluble polymer (5) was obtained. The water-soluble polymer (5) had a weight average molecular weight of 550,000 and an insoluble content of 0.02%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Synthesis Example 6
In a beaker having a capacity of 500 ml, 17.69 g of acrylic acid, 29.05 g of a 37% aqueous solution of sodium acrylate, 5.41 g of acrylamide, 39.63 g of methoxyethyl acrylate, and 55.56 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, 1.14 g of a sodium hypophosphite 2.0% aqueous solution as a chain transfer agent with stirring (0.03 g relative to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator. 1.52 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 35.0 mol% acrylic acid, 15.0 mol% sodium acrylate, 10.0 mol% acrylamide, and 40.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction liquid was 50%, and the liquid temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, and is acrylic acid / sodium acrylate / acrylamide / methoxyethyl acrylate = 35.0 / 15.0 / 10.0 / 40.0 (molar ratio) according to the present invention. A water-soluble polymer (6) having a neutralization degree of 30 mol% was obtained. The water-soluble polymer (6) had a weight average molecular weight of 3.1 million and an insoluble content of 3.70%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Synthesis example 7
In a beaker having a capacity of 500 ml, 30.55 g of acrylic acid, 48.34 g of a 37% aqueous solution of sodium acrylate, 10.15 g of ethoxyethyl acrylate and 58.14 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, while stirring, 1.41 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.06 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator 1.41 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 63.0 mol% acrylic acid, 27.0 mol% sodium acrylate, and 10.0 mol% ethoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, A neutralization degree is 30 mol with acrylic acid / sodium acrylate / ethoxyethyl acrylate = 63.0 / 27.0 / 10.0 (molar ratio) according to the present invention. % Water-soluble polymer (7) was obtained. The water-soluble polymer (7) had a weight average molecular weight of 1.26 million and an insoluble content of 0.36%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Synthesis example 8
In a beaker having a capacity of 500 ml, 123.0 g of a 37% aqueous solution of sodium acrylate, 6.99 g of methoxyethyl acrylate, and 17.69 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, while stirring, 1.25 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.07 g with respect to 1 mol of the total monomer composition) and 2,2′- as a photopolymerization initiator Azobis-2-amidinopropane dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., trade name V-50) 1.07 g of 1% aqueous solution (0.020 g relative to 1 mol of the total monomer composition) was added to the reaction solution. Was prepared. The monomer composition in the reaction solution was 90.0 mol% sodium acrylate and 10.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 35%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Subsequently, it grind | pulverizes using a table-type grinder, The water-soluble polymer (100 mol% of neutralization degree) by the sodium acrylate / methoxyethyl acrylate = 90.0 / 10.0 (molar ratio) which concerns on this invention ( 8) was obtained. The water-soluble polymer (8) had a weight average molecular weight of 920,000 and an insoluble content of 0.16%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Synthesis Example 9
In a 500 ml beaker, 17.08 g of acrylic acid, 27.66 g of a 37% aqueous solution of sodium acrylate, 31.46 g of methoxyethyl acrylate, and 71.8 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Subsequently, 0.79 g of a sodium hypophosphite 1.0% aqueous solution as a chain transfer agent (0.013 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator while stirring. 1.21 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 42.0 mol% acrylic acid, 18.0 mol% sodium acrylate, and 40.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, A neutralization degree is 30 mol with acrylic acid / sodium acrylate / methoxyethyl acrylate = 42.0 / 18.0 / 40.0 (molar ratio) according to the present invention. % Water-soluble polymer (9) was obtained. The water-soluble polymer (9) had a weight average molecular weight of 38,000,000 and an insoluble content of 4.5%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Synthesis Example 10
In a 500 ml beaker, 22.54 g of acrylic acid, 36.31 g of a 37% aqueous solution of sodium acrylate, 13.00 g of acrylamide, 9.53 g of methoxyethyl acrylate, and 66.06 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, 1.10 g of a sodium hypophosphite 2.0% aqueous solution as a chain transfer agent (0.03 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator while stirring. 1.46 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 45.5 mol% acrylic acid, 19.5 mol% sodium acrylate, 25.0 mol% acrylamide, and 10.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, and is acrylic acid / sodium acrylate / acrylamide / methoxyethyl acrylate = 45.5 / 19.5 / 25.0 / 10.0 (molar ratio) according to the present invention. A water-soluble polymer (10) having a neutralization degree of 30 mol% was obtained. The water-soluble polymer (10) had a weight average molecular weight of 2.6 million and an insoluble content of 2.60%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Comparative Synthesis Example 1
In a beaker having a capacity of 500 ml, 36.94 g of acrylic acid, 58.18 g of a 37% aqueous solution of sodium acrylate, and 51.82 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, while stirring, 1.53 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.06 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator. 1.53 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 70.0 mol% acrylic acid and 30.0 mol% sodium acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Subsequently, it grinds | pulverizes using a table-type grinder, A comparative water-soluble polymer (1 ) The comparative water-soluble polymer (1) had a weight average molecular weight of 1.83 million and an insoluble content of 1.43%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Comparative Synthesis Example 2
In a beaker having a capacity of 500 ml, 2.73 g of acrylic acid, 5.61 g of a 37% aqueous solution of sodium acrylate, 54.22 g of methoxyethyl acrylate, and 85.45 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, 0.98 g of a sodium hypophosphite 3.0% aqueous solution as a chain transfer agent (0.06 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator while stirring. 0.98 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 10.5 mol% acrylic acid, 4.5 mol% sodium acrylate, and 85.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 40%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, A neutralization degree is 30 mol with acrylic acid / sodium acrylate / methoxyethyl acrylate = 10.5 / 4.5 / 85.0 (molar ratio) according to the present invention. % Comparative water-soluble polymer (2) was obtained. The comparative water-soluble polymer (2) had a weight average molecular weight of 1,470,000 and an insoluble content of 0.04%. The weight average molecular weight is a molecular weight measured by the above light scattering method.

Comparative Synthesis Example 3
In a beaker having a capacity of 500 ml, 12.82 g of acrylic acid, 20.75 g of 37% aqueous solution of sodium acrylate, 23.60 g of methoxyethyl acrylate, and 90.01 g of ion-exchanged water were collected and mixed. The beaker containing the mixed solution was covered with a wrap, and dissolved oxygen in the mixed solution was removed by bubbling nitrogen while cooling. Next, 1.91 g of sodium hypophosphite 5.0% aqueous solution as a chain transfer agent (0.21 g with respect to 1 mol of the total monomer composition) and Darocur (DC) 1173 as a photopolymerization initiator while stirring. 0.91 g of 1% acrylic acid solution (made by Ciba Specialty Chemicals, chemical name; 2-hydroxy-2-methyl-1-phenyl-propan-1-one) (1 mol of total monomer composition) 0.020 g) was added to the reaction solution. The monomer composition in the reaction solution was 42.0 mol% acrylic acid, 18.0 mol% sodium acrylate, and 40.0 mol% methoxyethyl acrylate.

The total monomer concentration in the reaction solution was 30%, and the solution temperature was adjusted to 7 ° C. The reaction solution was irradiated for 15 minutes at a light intensity of 22 W / m ² using near-ultraviolet light (black light mercury lamp manufactured by Toshiba Corporation, model name H400BL-L) having a wavelength range of 300 to 450 nm. Polymerization started immediately after the start of irradiation. Irradiation was continued for 15 minutes to complete the polymerization. After cooling, the resulting gel polymer was cut with scissors and dried at 120 ° C. for 5 hours using a vacuum dryer. Then, it grind | pulverizes using a table-type grinder, A neutralization degree is 30 mol with acrylic acid / sodium acrylate / methoxyethyl acrylate = 42.0 / 18.0 / 40.0 (molar ratio) according to the present invention. % Comparative water-soluble polymer (3) was obtained. The comparative water-soluble polymer (3) had a weight average molecular weight of 410,000 and an insoluble content of 0.02%. The weight average molecular weight is a molecular weight measured by the above light scattering method.
The results of the above synthesis examples and comparative synthesis examples are summarized in Table 1.

Abbreviations in Table 1 are AA: acrylic acid, AAAa: sodium acrylate, AME: methoxyethyl acrylate, MAA: methacrylic acid, AAm: acrylamide. “Mw” is a weight average molecular weight.

Example 1
(Preparation of self-hardening mud)
In Examples and Comparative Examples, self-hardening mud was prepared using the standard soil, cement, and water shown below.
Standard soil: Mixture of 80 parts of clay, 60 parts of silt, 136 parts of clay, and 4 parts of sandCement: Blast furnace cement B manufactured by Taiheiyo Cement Co., Ltd.
Water: Tap water Self-hardening mud: Mixture of 16 parts of standard soil, 6.9 parts of cement, and 17.1 parts of water (fluidity evaluation)
40 g of self-hardening mud was weighed in a pack ace with a capacity of 100 cc. Next, after adding a predetermined amount of the water-soluble polymer (1) obtained in Synthesis Example 1 and stirring and mixing, if the fluidity is lost while observing the state of the mud (self-hardening mud), add 4 g of cement. Mixed. The minimum addition amount of the water-soluble polymer (1) when the mud was granulated was determined, and the results are shown in Table 2.

Examples 2-10
The minimum amount of water-soluble polymer added was determined in the same manner as in Example 1 except that the water-soluble polymers (2) to (10) obtained in Synthesis Examples 2 to 10 were used, and the results are shown in Table 2. Indicated.

In Table 2, the “minimum addition amount (to mud)” is the minimum addition mass (unit: mass%) of the water-soluble polymer (1) with respect to 100 mass% of the self-hardening mud. The same applies to Table 3.

Comparative Examples 1-3
The minimum addition amount of the comparative water-soluble polymer was determined in the same manner as in Example 1 except that the comparative water-soluble polymers (1) to (3) obtained in Comparative Synthesis Examples 1 to 3 were used. It is shown in Table 3.
Comparative Example 4
The treatment was carried out in the same manner as in Example 1 except that sodium polyacrylate having a weight average molecular weight of 6 million was used. However, even when 0.6% by mass was added, no granulated product was obtained.

Claims (7)

A fluidity reducing agent for water-containing soil comprising a water-soluble polymer (P),
The water-soluble polymer (P) is (meth) acrylic acid (salt) monomer (A) 20 to 99 mol%, the following general formula (1);
^{_{CH 2 = C (R) -COOZ}} 1 (O) p Z 2 OX (1)
(In the formula, R represents a hydrogen atom or a methyl group. Z ¹ and Z ² are the same or different and represent an alkylene group having 8 or less carbon atoms. X represents a hydrocarbon group having 4 or less carbon atoms. P represents an integer of 0 or 1.) The (meth) acrylic acid ester monomer (B) represented by 1 to 80 mol%, and the monomers (A) and (B) It is obtained by polymerizing 100 mol% of a monomer component containing 0 to 30 mol% of another copolymerizable monomer (C), and has a weight average molecular weight of 500,000 or more. Fluidity reducing agent. The fluidity reducing agent according to claim 1, wherein the content ratio of the (meth) acrylic acid ester monomer (B) is 5 to 50 mol%. The fluidity reducing agent according to claim 1 or 2, wherein the (meth) acrylic acid ester monomer (B) is methoxyethyl acrylate. The fluidity reducing agent according to any one of claims 1 to 3, wherein an insoluble content of the water-soluble polymer (P) is 5% by mass or less. A method for treating hydrous soil, wherein the fluidity reducing agent according to any one of claims 1 to 4 is used. Furthermore, a hydraulic substance is used, The processing method of the hydrous soil of Claim 5 characterized by the above-mentioned. The method for treating a hydrous soil according to claim 5 or 6, wherein the fluidity reducing agent is added to the hydrous soil to reduce the fluidity of the hydrous soil and to granulate the hydrous soil.