JP5226143B1 - Soil cement dispersant - Google Patents

Abstract

Disclosed is a soil cement dispersant having excellent dispersion holding power.
A copolymer (X) comprising a (meth) acrylic acid alkaline earth metal salt (A) unit and a copolymerizable monomer (B) unit, comprising (meth) acrylic acid alkaline earth metal salt A soil cement dispersant comprising (A) 20 to 85 mol% of a unit and 15 to 80 mol% of a copolymerizable monomer (B) unit, and a soil cement composition containing the soil cement dispersant.
[Selection figure] None

Description

  The present invention relates to a soil cement dispersant.

  The soil cement dispersing agent (fluidizing agent) has a function of dispersing the soil cement particles when added to the soil cement, and can improve the efficient workability of the soil cement construction.

  Patent Document 1 discloses a fluidizing agent for soil cement comprising an alkaline earth metal acrylate, an alkali metal acrylate, a copolymer having acrylic acid as an essential constituent monomer, an alkali metal carbonate, and the like. It is disclosed that fluidity can be imparted to soil cement.

  Patent Document 2 discloses a fluidizer for soil cement containing a low molecular weight polymer having a carboxylic acid or a monovalent salt thereof as a main constituent monomer unit and a weight average molecular weight of 25,000 or less and an alkali metal carbonate. Yes.

  Patent Document 3 discloses a powder additive for ground improvement comprising a polymer compound having a carboxylic acid group, wherein the carboxylic acid group of the polymer compound is neutralized with an alkaline earth metal in an equivalent amount of 10 to 80%. However, it is described that it is possible to improve the excavability by improving the fluidity of the soil cement slurry.

JP 2010-159183 A Japanese Patent No. 3554496 JP 2001-172629 A

  However, conventional soil cement dispersants (fluidizing agents) can maintain the dispersibility of the cement for only a short time, and have insufficient ability to retain high dispersibility for a long time, that is, dispersion retention.

  An object of the present invention is to provide a soil cement dispersant (fluidizing agent) having excellent dispersion holding power.

  The present inventors have repeatedly studied to achieve the above object, and have focused on the copolymer (X) containing a divalent salt constituent unit. In the field of cement admixture, a polymer containing a monovalent salt that is easily soluble in water (for example, a sodium salt) has been generally used instead of a polymer containing a divalent salt whose viscosity increases with an increase in the degree of neutralization. (For example, refer to paragraph [0016] of Japanese Patent Laid-Open No. 8-23962). Under such circumstances, the present inventors have found that a copolymer (X) containing a (meth) acrylic acid alkaline earth metal salt (A) unit and a copolymerization monomer (B) unit at a specific ratio is contained in cement. It has been found that it exhibits excellent dispersion holding power. The present invention is based on such knowledge.

  The soil cement dispersant of the present invention is characterized in that a copolymer composed of 20 to 85 mol% (meth) acrylic acid alkaline earth metal salt (A) units and 15 to 80 mol% of copolymerizable monomer (B) units. It is summarized as including (X).

  ADVANTAGE OF THE INVENTION According to this invention, the soil cement dispersing agent excellent in dispersion | distribution holding power, the soil cement composition containing this, and its manufacturing method are provided.

FIG. 1 is a graph showing the results of evaluation of dispersion holding power of Examples (no addition of sodium carbonate). FIG. 2 is a graph showing the results of evaluation of dispersion holding power in Examples (addition of sodium carbonate). FIG. 3 is a graph showing the results of evaluation of dispersion holding power in Examples (addition of sodium carbonate). FIG. 4 is a graph showing the results of evaluation of dispersion holding power in Examples (addition of sodium carbonate).

  The soil cement dispersant of the present invention contains a copolymer (X). Copolymer (X) as an active ingredient is composed of (meth) acrylic acid alkaline earth metal salt (A) units and copolymerization monomer (B) units.

  Examples of the alkaline earth metal salt of (meth) acrylic acid alkaline earth metal salt (A) include beryllium, magnesium, calcium, strontium and barium. You may use these individually or in mixture. Of these, beryllium, magnesium and calcium are preferred, magnesium and calcium are more preferred, and magnesium is more preferred.

  The content (mol%) of the (meth) acrylic acid alkaline earth metal salt (A) unit in the copolymer (X) is preferably 20 to 85 mol%, more preferably 20 to 60 mol%, still more preferably. Is 35 to 60 mol%, still more preferably 50 to 60 mol%. Within this range, the dispersion holding force (fluid holding force) is further improved. In particular, when the alkaline earth metal is magnesium, it is possible to avoid corrosion of the metal (iron) by the copolymer (X) by setting it to 50 to 60 mol%, and the storage equipment and the piping of the addition device are made of iron. The member can be used.

  Copolymer (X) contains 20 to 85 mol% of (meth) acrylic acid alkaline earth metal salt (A) units and 15 to 80 mol% of copolymerized monomer (B) units, and contains (meth) acrylic acid alkaline earth. It preferably contains 20 to 60 mol% of the metal salt (A) unit and 40 to 80 mol% of the comonomer (B) unit.

  In addition, content (mol%) of the said (A) unit and content (mol%) of the following (B) unit made the total number of moles of all the units of copolymer (X) 100 mol%. Content in case.

  As the copolymerization monomer (B) unit in the copolymer (X), (meth) acrylic acid (B1) unit, (meth) acrylic acid alkali metal salt (B2) unit, vinyl monomer (salt) (B3 ) Units. The copolymerization monomer (B) unit is at least one selected from (meth) acrylic acid (B1) units, (meth) acrylic acid alkali metal salt (B2) units, and vinyl monomer (salt) (B3) units. It is preferably composed of units. The copolymerizable monomer (B) unit is preferably composed of a (meth) acrylic acid (B1) unit and / or a (meth) acrylic acid alkali metal salt (B2) unit.

  The content (mol%) of the copolymer monomer (B) unit in the copolymer (X) is 15 to 80 mol%, more preferably 40 to 80 mol%, still more preferably 40 to 65 mol%, Even more preferably, it is 40-50 mol%. Within this range, the dispersion holding force (fluid holding force) is further improved.

  Examples of the alkali metal of the (meth) acrylic acid alkali metal salt (B2) unit include lithium, sodium, potassium, rubidium and cesium. You may use these individually or in mixture. Of these, lithium, sodium and potassium are preferable, lithium and sodium are more preferable, and sodium is more preferable.

  The vinyl monomer constituting the vinyl monomer (salt) (B3) unit or a salt thereof is not particularly limited as long as it can be copolymerized with, for example, an alkali earth metal (meth) acrylate (A). C4-20 unsaturated carboxylic acid (salt), C4-20 unsaturated carboxylic acid ester, C4-20 fatty acid vinyl ester, C2-20 olefin, C3-5 unsaturated Monomers such as saturated nitriles, unsaturated amides having 2 to 8 carbon atoms and unsaturated ethers having 5 to 60 carbon atoms can be used.

  As the unsaturated carboxylic acid (salt) (unsaturated carboxylic acid or salt thereof), for example, unsaturated monocarboxylic acid, unsaturated dicarboxylic acid and salts thereof (salts similar to acrylates can be used). And the content ratio is the same).

  Examples of the unsaturated monocarboxylic acid include aliphatic monocarboxylic acids having 4 to 10 carbon atoms, alicyclic monocarboxylic acids having 6 to 10 carbon atoms, and aromatic monocarboxylic acids having 9 to 17 carbon atoms. .

  Examples of the aliphatic monocarboxylic acid include methacrylic acid, crotonic acid, 3-butenoic acid, 2-pentenoic acid, 3-pentenoic acid, 4-pentenoic acid, 3-methyl-2-butenoic acid, and 3-methyl-3. -Butenoic acid, 2-methyl-3-butenoic acid, 2-methyl-2-butenoic acid, 2-ethyl-2-propenoic acid, 2-hexenoic acid, 4-methyl-2-pentenoic acid, 2-methyl-2 -Pentenoic acid, 2-heptenoic acid, 4,4-dimethyl-2-pentenoic acid, 2-octenoic acid, 3-methyl-2-heptenoic acid, 2-nonenoic acid, 3-methyl-2-octenoic acid, 2- Examples include decenoic acid and 2-hydroxypropenoic acid.

  Examples of the alicyclic monocarboxylic acid include 1-cyclopentenecarboxylic acid, 3-cyclopentenecarboxylic acid, 4-cyclopentenecarboxylic acid, 1-cyclohexenecarboxylic acid, 3-cyclohexenecarboxylic acid, 4-cyclohexenecarboxylic acid, and 1-cyclohexane. Heptenecarboxylic acid, 3-cycloheptenecarboxylic acid, 4-cycloheptenecarboxylic acid, 5-cycloheptenecarboxylic acid, 1-cyclooctenecarboxylic acid, 3-cyclooctenecarboxylic acid, 4-cyclooctenecarboxylic acid, 5-cyclooctene carboxylic acid, 1-cyclononene carboxylic acid, 3-cyclononene carboxylic acid, 4-cyclononene carboxylic acid, 5-cyclononene carboxylic acid, 1-cyclodecene carboxylic acid, 3-cyclodecene carboxylic acid, 4 -Cyclodecene carboxylic acid and 5-cyclo Sen carboxylic acid and the like.

  Examples of the aromatic monocarboxylic acid include orthocarboxystyrene, paracarboxystyrene, cinnamic acid, atropaic acid (α-phenylacrylic acid), benzyl (meth) acrylate, 5-vinyl-1-naphthalenecarboxylic acid, 4- Examples thereof include vinyl-1-naphthalene carboxylic acid and 4-vinyl-1-anthraquinone carboxylic acid.

  Examples of unsaturated dicarboxylic acids include aliphatic dicarboxylic acids having 4 to 11 carbon atoms, alicyclic dicarboxylic acids having 6 to 10 carbon atoms, aromatic dicarboxylic acids having 9 to 17 carbon atoms, and intramolecular acid anhydrides thereof. Etc. are included.

  Examples of the aliphatic dicarboxylic acid include maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, butenedioic acid, 2-pentenedioic acid, 3-pentenoic acid, 4-pentenoic acid, and 2-methyl-2- Butenedioic acid, 2-ethyl-2-propenoic acid, 2-hexenedioic acid, 2-heptenedioic acid, 2-octenoic acid, 3-methyl-2-heptenedioic acid, 2-nonenedioic acid, 2-decenedioic acid And acid and 2-hydroxyptenelodioic acid.

  Examples of the alicyclic dicarboxylic acid include 1,2-cyclopentene dicarboxylic acid, 1,3-cyclopentene dicarboxylic acid, 1,4-cyclopentene dicarboxylic acid, 1,2-cyclohexene dicarboxylic acid, 1,3-cyclohexene dicarboxylic acid, 1,4-cyclohexene dicarboxylic acid, 1,2-cycloheptene dicarboxylic acid, 1,3-cycloheptene dicarboxylic acid, 1,4-cycloheptene dicarboxylic acid, 1,5-cycloheptene dicarboxylic acid, 1, 2-cyclooctene dicarboxylic acid, 1,3-cyclooctene dicarboxylic acid, 1,4-cyclooctene dicarboxylic acid, 1,5-cyclooctene dicarboxylic acid, 1,2-cyclononene dicarboxylic acid, 1,3-cyclononene dicarboxylic acid Acid, 1,4-cyclononene dicarboxylic acid, 1,5-cyclononene dicar Examples thereof include boric acid, 1,2-cyclodecene dicarboxylic acid, 1,3-cyclodecene dicarboxylic acid, 1,4-cyclodecene dicarboxylic acid, and 1,5-cyclodecene dicarboxylic acid.

  Examples of the aromatic dicarboxylic acid include o, p-dicarboxystyrene, o, p-dicarboxystyrene, 4-vinyl-1,2-naphthalenedicarboxylic acid and 4-vinyl-1,3-anthraquinone dicarboxylic acid. Can be mentioned.

  Examples of intramolecular acid anhydrides of unsaturated dicarboxylic acids include maleic anhydride, itaconic anhydride, and citraconic anhydride.

  Examples of unsaturated carboxylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ethylhexyl (meth) acrylate, stearyl (meth) acrylate, and (meth) acrylic acid. Examples include benzyl, methyl crotonate, dimethyl maleate, hexyl maleate and butyl itaconate.

  Examples of the fatty acid vinyl ester include vinyl acetate, vinyl palmitate, vinyl laurate, and vinyl stearate.

  Examples of the olefin include α-olefins (ethylene, propylene, butylene, hexylene, octylene, undecylene, tetradecylene, and nonadecylene), diisobutylene, butadiene, piperylene, chloroprene, pinene, limonene, indene, cyclopentadiene, bicyclopentadiene, and the like. Examples include ethylidene norbornene.

  Examples of unsaturated nitriles include (meth) acrylonitrile, cyanopropene, and cyanopentene.

  Examples of the unsaturated amide include (meth) acrylamide, N-methyl (meth) acrylamide, N-2-hydroxymethyl (meth) acrylamide, N- (2-aminoethyl) (meth) acrylamide and N- (2- And dimethylaminoethyl) (meth) acrylamide.

  Examples of the unsaturated ether include methoxypolyethylene glycol (polymerization degree 25) (meth) acrylate, methoxypolyethylene glycol (polymerization degree 5) (meth) acrylate, polyethylene glycol (polymerization degree 20) mono (meth) acrylate and polyethylene glycol ( Degree of polymerization 10) Mono (meth) acrylate and the like.

  Of these vinyl monomers, unsaturated carboxylic acid esters and unsaturated nitriles are preferred, unsaturated nitriles are more preferred, and acrylonitrile is more preferred.

  The weight average molecular weight (Mw) of the copolymer (X) is preferably 1,000 to 10,000, more preferably 2,000 to 7,000, still more preferably 3,000 to 5,500. The molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) is preferably 1.1 to 3.0, more preferably 1.2 to 2.5, and still more preferably 1.2 to 2.0. . Within this range, the dispersion holding power (fluidity holding power) of the soil cement is further improved.

  The weight average molecular weight (Mw) and number average molecular weight (Mn) are measured by a gel permeation chromatography (GPC) method using (poly) acrylic acid having a known molecular weight as a standard substance (column temperature 40 ° C., elution). Liquid: 0.1-MPB disodium hydrogen phosphate aqueous solution: 0.1-MPB sodium dihydrogen phosphate aqueous solution = 1: 1 (molar ratio), flow rate 0.8 ml / min, sample concentration: 0.4 wt% Eluent solution).

  The copolymer (X) can be obtained, for example, by using a usual polymerization method for vinyl monomers. As the polymerization method, for example, suspension polymerization, bulk polymerization, solution polymerization and the like can be applied, and solution polymerization is preferable from the viewpoint of productivity.

  Copolymer (X) is, for example, (meth) acrylic acid alkaline earth metal salt (A), (meth) acrylic acid (B1), (meth) acrylic acid alkali metal salt (B2) and, if necessary, vinyl monomer A method of producing a product (salt) (B3) by copolymerization (method 1), (meth) acrylic acid (B1) and, if necessary, a vinyl monomer (salt) (B3), It can be obtained by a method of neutralizing with an alkaline earth metal oxide, an alkali metal hydroxide or the like (Method 2) and a method of combining these Methods 1 and 2 (Method 3).

  A polymerization catalyst can be used for the polymerization. As the polymerization catalyst, an ordinary polymerization catalyst or the like is used, and azo compounds, persulfates, inorganic peroxides, redox catalysts, organic peroxides, and the like are included. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 4,4′-azobis-4-cyanovaleric acid, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile, 2, 2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane-1-albonitrile), 2,2'-azobis (2,4,4-trimethylpentane), dimethyl 2,2 ' -Azobis (2-methylpropionate), 2,2'-azobis [2- (hydroxymethyl) propionitrile], 1,1'-azobis (1-acetoxy-1-phenylethane) and the like. Examples of the salt include ammonium persulfate, potassium persulfate, sodium persulfate, etc. Examples of the inorganic peroxide include perborate and water peroxide. Examples of the redox catalyst include ascorbic acid-hydrogen peroxide, etc. Examples of the organic peroxide include benzoyl peroxide, etc. These polymerization catalysts may be used alone or in combination. Of these, persulfates and azo compounds are preferred, persulfates and 2,2′-azobisisobutyronitrile are more preferred, ammonium persulfate, potassium persulfate and sodium persulfate are more preferred. It is.

  When the polymerization catalyst is used, the amount (% by weight) of the polymerization catalyst is preferably 3 to 100, more preferably 8 to 80, and still more preferably 10 to 60, based on the weight of the constituent monomer.

In the case of solution polymerization and suspension polymerization, the solvent includes water (tap water, ion exchange water, industrial water, etc.), alcohol solvent (methanol, ethanol, isopropyl alcohol, etc.) and / or aromatic solvent (toluene, xylene, etc.). Etc. can be used. Of these, water, a mixed solvent of water and an alcohol solvent are preferable, a mixed solvent of water and alcohol is more preferable, and a mixed solvent of ion-exchanged water and isopropyl alcohol is more preferable.
When using a solvent, the amount (% by weight) used is preferably 50 to 900, more preferably 60 to 800, and still more preferably 100 to 600, based on the total weight of the constituent monomers.

  The polymerization reaction temperature is preferably about 40 to 130 ° C., and the polymerization reaction time is preferably about 1 to 15 hours.

  In addition, you may superpose | polymerize, dripping the whole quantity or one part of a structural monomer. Moreover, you may superpose | polymerize, dripping the whole quantity or one part of a polymerization catalyst. Moreover, you may superpose | polymerize, dripping the whole quantity or one part of a solvent with a structural monomer or a polymerization catalyst. On the other hand, the entire amount of the solvent may be charged in a polymerization tank and polymerization may be performed while removing the solvent. Among these, from the viewpoint of productivity and the like, the method of dropping the whole amount of the constituent monomer and the polymerization catalyst and the method of dropping a part of the solvent together with the constituent monomer or the polymerization catalyst are preferable, and more preferably the constituent unit. In this method, the entire amount of the monomer and the polymerization catalyst is dropped together with a part of the solvent.

  The form of the copolymer (X) is not particularly limited, and may be liquid or solid.

  When the copolymer (X) is liquid, it means a state in which the copolymer (X) is dissolved or dispersed in an aqueous solvent. In this case, the copolymer (X) may be obtained by suspension polymerization or solution polymerization without removing all the solvent, or the copolymer (X) obtained by bulk polymerization or the like may be dissolved in an aqueous solvent. Alternatively, it may be obtained by dispersing.

  Examples of the aqueous solvent include water, alcohols having 1 to 6 carbon atoms (such as ethyl alcohol, methyl alcohol, ethylene glycol and diethylene glycol), and ketones having 1 to 6 carbon atoms (such as methyl isobutyl ketone and acetone). They may be used alone or in combination.

  On the other hand, when the copolymer (X) is solid, it may be a solid made of the copolymer (X), or may be a powder having the liquid copolymer (X) supported on the powder. .

  In the case of a solid comprising the copolymer (X), it may be obtained by bulk polymerization, or after the solution or dispersion containing the copolymer (X) is obtained by suspension polymerization or solution polymerization, the solvent is removed. May be obtained.

  As a method for removing the solvent from the solution or dispersion containing the copolymer (X), known methods such as a dry pulverization method, a freeze pulverization method, a spray dryer method, and a drum dryer method can be used. Of these, the dry pulverization method and the spray dryer method are preferred.

  The size (mm; maximum length) of the solid copolymer (X) is preferably from 0.01 to 5, more preferably from 0.05 to 5 from the viewpoint of the solubility of the soil cement dispersant of the present invention. 3, More preferably, it is 0.08-1.

  When the liquid copolymer (X) is supported on a powder, examples of the powder include activated carbon, calcium carbonate, silica, zeolite, shirasu balloon, and bentonite.

  As a method for supporting the liquid copolymer (X) on these powders, the powder and the liquid copolymer (X) can be obtained by using a known stirring mixer (such as a ribbon mixer and a Henschel mixer). A method of stirring and mixing can be applied.

  Among the forms of the copolymer (X), a liquid is preferable, and a state where the copolymer (X) is dissolved in an aqueous solvent is more preferable.

  The soil cement dispersant of the present invention may further contain sodium carbonate. This is preferable because a higher dispersion holding force can be obtained. The content (weight) of sodium carbonate is preferably 1 to 10, more preferably 4 to 6, when the content (weight) of the copolymer (X) is 1. Within this range, the influence on the curability of the soil cement is small, and the dispersion holding power (fluidity holding power) is further improved.

  The form of sodium carbonate is not particularly limited and may be liquid or solid.

  When sodium carbonate is liquid, it means a state in which sodium carbonate is dissolved or dispersed in an aqueous solvent. In this case, sodium carbonate may be purchased as a liquid product from the market, or a solid product may be purchased and dissolved or dispersed in an aqueous solvent.

  On the other hand, when sodium carbonate is solid, it may be a solid made of sodium carbonate or a powder in which sodium carbonate is supported on a powder.

  In the case of a solid made of sodium carbonate, a solid product may be purchased from the market, or may be obtained by removing the solvent from a liquid product purchased from the market.

  The method for removing the solvent from the solution or dispersion containing sodium carbonate is the same as in the case of the copolymer (X) including preferable ones.

  The size (mm; maximum length) of the solid sodium carbonate is preferably 0.01 to 10, more preferably 0.05 to 8, particularly preferably from the viewpoint of the solubility of the soil cement dispersant of the present invention. Is 0.08-5.

  When liquid sodium carbonate is supported on a powder, the powder and the supporting method are the same as those for the copolymer (X).

  Of the forms of sodium carbonate, solid is preferable, and solid is more preferable.

  In the soil cement dispersant of the present invention, known additives used together with cement (AE agent, AE water reducing agent, high performance water reducing agent, retarder, early strength agent, curing accelerator, foaming agent, foaming agent, anti-foaming agent) Foaming agent, quick setting agent, swelling agent, thickening agent, waterproofing agent and the like). These may be used alone or in combination.

  When the additive is contained, the content (% by weight) thereof is preferably 1 to 30, more preferably 2 to 15, and still more preferably 3 based on the total weight of the copolymer (X) and sodium carbonate. -10.

  Further, the soil cement dispersant of the present invention can contain an aqueous solvent or the like. When a water-soluble solvent is contained, the content (% by weight) is determined from the viewpoint of handling properties (viscosity, etc.) of the soil cement dispersant, copolymer (X), sodium carbonate, and additives added as necessary. Is preferably 70 to 2,000, more preferably 80 to 1,000, and still more preferably 90 to 500, based on the total weight of.

  The form of the soil cement dispersant of the present invention is (1) a form in which the copolymer (X) and sodium carbonate are present together (which may be liquid or solid, and the copolymer (X) and sodium carbonate are May be reacted} or (2) the form in which the copolymer (X) and sodium carbonate are present separately (each may be liquid or solid, and each may be mixed during use) . In addition, in the case of (2), the additive and / or water contained as necessary may be included in each or in any case.

  The soil cement dispersant of the present invention can be used in the form of an aqueous solution or in the form of powder after drying. The time when the soil cement dispersant is added to other components constituting the soil cement composition or hydraulic materials other than the soil cement composition may be when the soil cement composition is used. In addition, the soil cement dispersant of the present invention in a powdered form is previously mixed with components other than water constituting the soil cement composition, such as cement powder and dry mortar, and plastering, floor finishing, It can also be used as a premix product to which water is added in the case of grout.

  The soil cement dispersant of the present invention can be added to a hydraulic material such as cement and used as a soil cement composition such as cement paste, mortar, concrete, or plaster.

  The soil cement composition of this invention should just contain a soil cement dispersing agent, and the hydraulic material combined is not specifically limited. Examples of the hydraulic material include cement, gypsum (semihydrate gypsum, dihydrate gypsum, etc.), and dolomite. The most common hydraulic material is cement.

  The cement is not particularly limited. For example, Portland cement (ordinary, early strength, very early strength, moderate heat, sulfate-resistant and low alkali type of each), various mixed cements (blast furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, Super fast cement (1 clinker fast cement, 2 clinker fast cement, magnesium phosphate cement), grout cement, oil well cement, low exothermic cement (low exothermic blast furnace cement, fly ash mixed low exothermic blast furnace cement, belite High-content cement), ultra-high-strength cement, cement-based solidified material, eco-cement (cement produced using at least one of municipal waste incineration ash and sewage sludge incineration ash). Blast furnace slag, converter slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, fine powder such as limestone powder, gypsum and the like may be added to the cement.

  Moreover, the soil cement composition may contain the aggregate. The aggregate may be either a fine aggregate or a coarse aggregate. Examples of aggregates include natural aggregates such as sand and gravel; processed aggregates such as crushed stone, crushed sand and recycled aggregates; blast furnace slag, converter slag, ferronickel slag, copper slag, general waste and sewage sludge or Slag aggregates such as molten slag obtained by melting and solidifying those incineration ash; recycled aggregates, etc .; siliceous, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromic, magnesia, etc. Refractory aggregate.

  The blending ratio of the soil cement dispersant in the soil cement composition is not particularly limited, but usually 0.01% by weight as the solid content conversion rate of the copolymer (X) with respect to the total weight of the cement. % Or more, preferably 0.05% by weight or more, more preferably 0.1% by weight or more, still more preferably 0.5% by weight or more, and still more preferably 0.7% by weight or more. By setting it within this range, the dispersion holding force is sufficiently exhibited. On the other hand, the upper limit is usually 5.0% by weight or less, preferably 3.0% by weight or less, more preferably 1.5% by weight or less. By setting this range, the soil cement can be modified within an economically advantageous range.

  Confirmation of the dispersion holding power of the soil cement dispersant of the present invention is conducted in accordance with the 1.2 cylinder method of JHS A 313 “Testing methods for air mortar and air milk” of the Japan Highway Public Corporation Standard (April 1992). It is clear by doing. Specific conditions are as in the examples described later. Although it depends on the type of cement, for example, the flow after 1.5 to 2 hours may be about 200 mm, and the flow value after 2 hours is more preferably 250 mm or more.

  The production method of the present invention is a method for producing a soil cement composition in which the copolymer (X) is added to the soil cement. The copolymer (X) and the soil cement are the same as those described in the section of the soil cement dispersant. The addition amount of the copolymer (X) is the same as that described in the section of the soil cement dispersant.

  In the production method of the present invention, sodium carbonate may be further added. About sodium carbonate, including the addition amount, it is the same as that described in the section of the soil cement dispersant. There is no restriction | limiting in the addition time to the soil cement of sodium carbonate, You may add simultaneously with copolymer (X), and you may add with a time difference, respectively. When adding with a time difference, adding sodium carbonate prior to the copolymer (X) is preferable from the viewpoint of increasing the dispersion holding power.

  The soil cement composition obtained by the production method of the present invention is excellent in dispersion retention. Confirmation of the dispersion holding power of the soil cement composition can be performed by the same method as described in the section of the soil cement dispersant.

  The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto.

<Production Reference Example 1> (Copolymer (1): used in Reference Examples 1, 5 and 7)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water. 24.3 parts of magnesium hydroxide [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions, and a 48% sodium hydroxide aqueous solution [reagent special grade, manufactured by Kanto Chemical Co., Ltd.] 277 was added. .3 parts were added separately. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (1) [magnesium acrylate salt (20 mol%)-acrylic acid sodium salt (80 mol%) copolymer]. The copolymer (1) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Production Example 2> (Copolymer (2): used in Examples 2, 6, 8 and 15)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water, followed by cooling to 30 ° C. and 40 ° C. or less with stirring. Then, 103.1 parts of magnesium hydroxide [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (2) [magnesium acrylate salt (85 mol%)-acrylic acid (15 mol%) copolymer]. The copolymer (2) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Production Example 3> (Copolymer (3): used in Examples 3 and 9)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water, followed by cooling to 30 ° C. and 40 ° C. or less with stirring. 24.3 parts of magnesium hydroxide [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (3) [magnesium acrylate (20 mol%)-acrylic acid (80 mol%) copolymer]. The copolymer (3) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Production Example 4> (Copolymer (4): used in Examples 4, 10 and 13)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water, followed by cooling to 30 ° C. and 40 ° C. or less with stirring. Then, 60.7 parts of magnesium hydroxide [special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (4) [magnesium acrylate salt (50 mol%)-acrylic acid (50 mol%) copolymer]. The copolymer (4) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Comparative Production Example 1> (Copolymer (5): used in Comparative Example 2)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of dropping, the temperature was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water, followed by cooling to 40 ° C. or lower. And the density | concentration was adjusted to 40% and the copolymer (5) [acrylic acid (100 mol%) copolymer] was obtained. The copolymer (5) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Comparative Production Example 2> (Copolymer (6): used in Comparative Example 3)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water, followed by cooling to 30 ° C. and 40 ° C. or less with stirring. Then, 121.3 parts of magnesium hydroxide [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (6) [magnesium acrylate (100 mol%) copolymer]. The copolymer (6) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Comparative Production Example 3> (Copolymer (7): used in Comparative Examples 4 and 6)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water. In this manner, 346.9 parts of a 48% aqueous sodium hydroxide solution (special grade reagent, manufactured by Kanto Chemical Co., Inc.) was gradually added in portions. And it added and adjusted the density | concentration to 40% and obtained the copolymer (7) [acrylic acid sodium salt (100 mol%) copolymer]. The copolymer (7) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Production Example 5> (Copolymer (8): used in Example 11)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water, followed by cooling to 30 ° C. and 40 ° C. or less with stirring. 42.5 parts of magnesium hydroxide [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer [magnesium acrylate (35 mol%)-acrylic acid (65 mol%) copolymer]. The copolymer had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Production Example 6> (Copolymer (9): used in Example 12)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water, followed by cooling to 30 ° C. and 40 ° C. or less with stirring. 48.6 parts of magnesium hydroxide [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (9) [magnesium acrylate salt (40 mol%)-acrylic acid (60 mol%) copolymer]. The copolymer (9) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Production Example 7> (Copolymer (10): used in Example 14)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water. Then, 72.8 parts of magnesium hydroxide [special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (10) [magnesium acrylate salt (60 mol%)-acrylic acid (40 mol%) copolymer]. The copolymer (10) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Production Reference Example 8> (Copolymer (11): used in Reference Example 16)
200.0 parts of ion-exchanged water and 300.0 parts of isopropyl alcohol are charged into a pressure-resistant reaction vessel equipped with a dropping line, a stirrer and a thermometer, and 300.0 parts of acrylic acid and 40% aqueous sodium persulfate solution 100. The reaction was carried out in a sealed state while dropping 0 parts from each separate dropping line at a constant rate over 3 hours. The reaction temperature was maintained at 80-100 ° C. After completion of the dropwise addition, the mixture was kept at 95 to 100 ° C. for 3 hours, and then isopropyl alcohol was removed under reduced pressure while dropping (hydrolyzing) 150.0 parts of ion-exchanged water. Then, 77.1 parts of calcium hydroxide [reagent special grade, manufactured by Wako Pure Chemical Industries, Ltd.] was gradually added in portions. Then, the concentration was adjusted to 40% by adding water to obtain a copolymer (11) [calcium acrylate salt (50 mol%)-acrylic acid (50 mol%) copolymer]. The copolymer (11) had a weight average molecular weight of 4,750 and a molecular weight distribution (Mw / Mn) of 1.5.

<Examples 2 to 4 , Reference Example 1 and Comparative Examples 1 to 3>
(1) Preparation of slurry Various materials were mixed according to Tables 1 and 2. Furthermore, each component shown in Table 3 was added to prepare a slurry. The soil used had a soil wet density of 1.77 g / cm ³ and a moisture content of 39%. The addition ratio of the copolymer (X) shown in Table 3 represents the addition weight in terms of solid content with respect to the weight of the cement in weight%.

(2) Evaluation of dispersion holding power The test was conducted according to the 1.2 cylinder method in JHS A 313 “Testing methods for air mortar and air milk” of Japan Highway Public Corporation Standard (April 1992).

  That is, the cylinder (inner diameter: 80 cm, height: 80 mm) was placed on a horizontal plate, and the slurry was gently put to the upper end of the cylinder. The cylinder was gently pulled up vertically. The diameter in the maximum direction and the diameter in the direction perpendicular to the slurry spreading in a plate shape with time after the pulling were measured, and the average of the measured values was calculated as the flow value (mm). The larger the flow value, the higher the dispersibility.

  The test results are shown in Table 3 and FIG.

As apparent from Table 3 and FIG. 1, the slurry of Examples 2 to 4 and Reference Example 1 has little change with time in the flow compared to the slurry of Comparative Examples 1 to 3, and in particular, Examples 3 and 4 and Reference Example 1 This slurry showed a remarkable dispersion holding power. This result shows that the soil cement dispersant of the present invention containing the copolymer (X) has an excellent dispersion holding power.

<Examples 6 and 8 to 10 , Reference Examples 5 and 7, and Comparative Examples 4 and 5>
(1) Preparation of slurry Various materials were mixed according to Table 4, and sodium carbonate agent “(product name; soda ash (industrial), manufacturer; Tokuyama, (solid state); granular, size (Table 5) Maximum length); maximum particle size 1.0 mm) "was added to prepare a slurry. The soil wet density of the soil shown in Table 4 was 1.77 g / cm ³ and the water content ratio was 39%. The addition ratio of the copolymer (X) and sodium carbonate shown in Table 5 represents the addition weight in terms of solid content with respect to the weight of cement in weight%.

(2) Evaluation of dispersion holding power In the same manner as in Example 1, evaluation of dispersion holding power was performed according to 1.2 of JHS A 313 “Testing methods for air mortar and air milk” of the Japan Highway Public Corporation Standard (April 1992). The test was conducted according to the cylinder method. The test results are shown in Table 5, FIG. 2 and FIG.

The slurry of Examples 6, 8 to 10 and Reference Examples 5 and 7 have less change in flow value with time compared to the slurry of Comparative Examples 4 to 5, and among them, the slurry of Examples 9 and 10 has a remarkable dispersion holding power. (Table 5 and FIG. 2). Further, the slurry of Reference Example 7 in which the amount of the copolymer (X) of Example 5 was doubled, and the slurry of Example 8 in which the amount of the copolymer (X) of Example 6 was doubled. The flow value did not change at all over time, indicating a remarkable dispersion holding force (FIG. 3). These results show that in the soil cement dispersant of the present invention, by using the copolymer (X) and sodium carbonate in combination, it has further excellent dispersion holding power, and the addition of the copolymer (X). It shows that an even better dispersion holding power is exhibited by increasing the amount.

Examples 11 to 15, Reference Example 16 and Comparative Example 6
As copolymer (X), copolymer (8) [Mg-35%] (Example 11), copolymer (9) [Mg-40%] (Example 12), copolymer (4) [ Mg-50%] (Example 13), Copolymer (10) [Mg-60%] (Example 14), Copolymer (2) [Mg-85%] (Example 15), Copolymer (11) A test was performed in the same manner as in Example 5 except that [Ca-50%] ( Reference Example 16) was used and the addition amount of Na ₂ (CO ₃ ) was 1.5%. As a control, the same test as in Example 5 was performed except that the copolymer (7) [Na-100%] was used instead of the copolymer (X) (Comparative Example 6). The test results are shown in FIG.

  Compared with the slurry of Comparative Example 6, the slurries of Examples 11 to 16 showed less change in flow value with time, and among them, the slurries of Examples 11 to 14 showed remarkable dispersion holding power (FIG. 4). This result shows that, in the present invention, the alkaline earth metal salt of the (meth) acrylic acid alkaline earth metal salt (A) unit is a divalent salt such as magnesium or calcium, thereby exhibiting excellent dispersion holding power. It is shown that.

Claims (6)

A copolymer (X) composed of a (meth) acrylic acid alkaline earth metal salt (A) unit and a copolymerizable monomer (B) unit,
The copolymerizable monomer (B) unit is a (meth) acrylic acid (B1) unit,
Alkaline earth metal of (meth) acrylic acid alkaline earth metal salt (A) unit is magnesium,
The (meth) acrylic acid alkaline earth metal salt (A) unit is 20 to 85 mol%, the copolymer monomer (B) unit is 15 to 80 mol%, and the weight average molecular weight of the copolymer (X) is 1, A soil cement dispersant comprising a copolymer (X) of 000 to 10,000 .   The soil cement dispersant according to claim 1, wherein the (meth) acrylic acid alkaline earth metal salt (A) unit is 20 to 60 mol% and the comonomer (B) unit is 40 to 80 mol%. The soil cement dispersant according to claim 1 or 2 , further comprising sodium carbonate. The soil cement composition containing the soil cement dispersing agent as described in any one of Claims 1-3 . The manufacturing method of the soil cement composition which adds the soil cement dispersing agent as described in any one of Claims 1-3 to a soil cement. The method for producing a soil cement composition according to claim 5 , wherein sodium carbonate is further added.

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