JP6199474B2 - Surface coating agent - Google Patents

Description

The present invention relates to surface-coated inorganic particles and a method for producing the same, a surface coating agent, and a method for producing a hydraulic composition.

In addition to the narrowly defined hydraulic particles that cause a hydration reaction in the presence of water, the hydraulic particles do not hydrate with water alone, but in the presence of a small amount of substance called a stimulant. There are latent hydraulic particles that cause In general, hydraulic particles are used in combination with a dispersant, water, and fine aggregates, coarse aggregates, and the like, if necessary, to obtain hydraulic compositions such as cement paste, mortar, and concrete. For example, to produce fresh (raw) concrete, in a mixer, in a narrow sense, hydraulic particles such as cement, dispersant, water, fine aggregate and coarse aggregate, and if necessary silica fume, blast furnace A method is employed in which fine powders such as slag and fly ash are added and then mixed for a certain period of time and kneaded until the dispersing agent disperses the paste and the fluidity becomes constant, that is, until the fluidity becomes stable. The dispersant is also referred to as a water reducing agent, and is used as an additive for imparting fluidity to the hydraulic composition. Usually, the dispersant is mixed with water in advance and added to the hydraulic particles. The time until the fluidity is stabilized after adding water (with a dispersant) to the hydraulic particles is referred to as the kneading time or the time until the kneading, but before the fluidity is stabilized. Usually takes a certain amount of time.

As a hydraulic composition containing a dispersant, for example, Patent Document 1 discloses a cement admixture containing a calcium aluminate compound having a predetermined physical property value and a water reducing agent. In this document, it is described that a water reducing agent can be used in a liquid or powder form in which a water reducing agent component is dissolved in water.

JP 2010-1000046 A JP 2011-068134 A Special table 2008-503432 gazette

As described above, the kneading time usually requires a certain time. In particular, the ultra high strength concrete having a low water / hydraulic particle mass ratio tends to increase the time until the fluidity is stabilized, that is, the kneading time. If this can be improved and the kneading time can be shortened, for example, the manufacturing time per batch in a concrete manufacturing plant can be shortened, which can greatly contribute to the improvement of productivity. However, at present, no technology that can sufficiently solve such problems has been found. In the technique described in Patent Document 1, even if the dispersant is used in powder form, it does not contribute to shortening the kneading time (Test Example 3-1 described later).

The present invention has been made in view of the above situation, and provides a surface-coated inorganic particle capable of significantly reducing the kneading time and capable of giving a hydraulic composition excellent in fluidity with high productivity and a method for producing the same. The purpose is to provide. Another object of the present invention is to provide a surface coating agent particularly suitable for obtaining such surface-coated inorganic particles, and a method for producing a hydraulic composition using the surface-coated inorganic particles.

As a result of various studies on the production technique of the hydraulic composition, the present inventor has produced a hydraulic composition in which part or all of the surface of the hydraulic inorganic particle is coated with an organic dispersant, and the particle When surface-coated inorganic particles having a carbon content ratio (carbon concentration) in the surface or in the vicinity of the surface are in a predetermined range, a kneading time until fluidity is stabilized can be remarkably shortened, and a hydraulic composition exhibiting high fluidity can be obtained. I found what I could give. It was also found that the same phenomenon occurs with surface-coated inorganic particles using pozzolanic active inorganic particles. Even when the mass ratio of water / hydraulic particles is low, if such surface-coated inorganic particles are used, a hydraulic composition exhibiting high fluidity can be easily obtained in a short time, so that productivity is improved. It will be very good. Moreover, the surface coating agent containing the polycarboxylic acid-based polymer containing polyalkylene glycol has the adsorptivity to the hydraulic inorganic particles and the pozzolanic active inorganic particles, and the particle dispersibility after the adsorption (that is, after the surface coating). It has also been found to be particularly suitable for use as a surface coating agent for these inorganic particles because it is extremely excellent. Then, the inventors have arrived at the present invention by conceiving that the above problems can be solved brilliantly.

Here, in Patent Document 2 described above, cement particles (for example, particle coating 22 in the figure) coated with a concrete fluidizing agent 13 as an additive are described. Since it is supplied by spraying together with a small amount of water, the fluidizing agent 13 cannot sufficiently coat the cement surface, and since the amount of water to be added is small, the cement particles are sufficiently applied during the surface coating. Cannot be distributed. Patent Document 3 describes that an aqueous composition containing polymer A having a predetermined structure is used as a cement grinding aid. This cement grinding aid is added to the clinker (cement raw material) as an aqueous composition that essentially contains a small amount of water, and in this case as well, the surface cannot be sufficiently coated during cement grinding, and cement particles are produced during grinding. Cannot be sufficiently dispersed. Moreover, since the technique of patent document 2, 3 uses water for a solvent, or the particle | grain surface is not fully coat | covered with the dispersing agent, the dispersibility of a fluidizing agent does not exhibit (the below-mentioned test example 7-1). ). Therefore, according to these techniques of Patent Documents 2 and 3, it is not possible to improve the fluidity and further shorten the kneading time.

The present invention comprises the following inventions (I) to (VII).
(I) Part or all of the surface of at least one inorganic particle selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles is coated with an organic dispersant, and silicon (Si) on the particle surface And the relative surface concentration of carbon (C) with respect to calcium (Ca) is measured by XPS, the relative surface concentration of carbon (C) is 0.35 to 50, and the depth at 1 to 2 nm from the particle surface Surface-coated inorganic particles having an average carbon (C) relative surface concentration of 0.15 to 50.
(II) The surface-coated inorganic particles, and the relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) on the surface of the inorganic particles per unit amount of the organic dispersant is 0.6 to 10 And surface-coated inorganic particles having a relative surface concentration of carbon (C) having an average depth of 1 to 2 nm from the particle surface of 0.2 to 5.
(III) The surface-coated inorganic particles, wherein the surface-coated inorganic particles have a hydration degree of 0.1 or less.
(IV) Hydraulic inorganic particles containing the surface-coated inorganic particles.
(V) A method for producing a hydraulic composition using the surface-coated inorganic particles.
(VI) A method for producing the surface-coated inorganic particles, wherein the production method comprises at least one inorganic particle selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles, an organic dispersant A method for producing surface-coated inorganic particles, which comprises a step of dispersing in a solvent and then distilling the solvent to powder.
(VII) A surface coating agent for inorganic particles used for obtaining the surface-coated inorganic particles, wherein the inorganic particles are at least one selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles. And the surface coating agent comprises a polycarboxylic acid-based polymer containing polyalkylene glycol.
The present invention is described in detail below. In addition, the form which combined each preferable form of this invention described below 2 or 3 or more is also a preferable form of this invention.

[Surface coated inorganic particles]
The surface-coated inorganic particles of the present invention have a form in which part or all of the surface of predetermined inorganic particles is coated with an organic dispersant.
The surface-coated inorganic particles are preferably in the range of, for example, 0.01 to 100 μm as an average particle size. By being in such a range, the kneading time can be further shortened, and it becomes possible to give a uniform fluidity to the obtained hydraulic composition. More preferably, it is 0.05-75 micrometers, More preferably, it is the range of 0.1-50 micrometers.

(Particle size measurement method)
In the present specification, the particle size of the particles can be measured using a commercially available particle size distribution measuring device. As an example, the sample can be ultrasonically dispersed with ethanol using a laser diffraction / scattering particle size distribution analyzer LA-910 manufactured by HORIBA, and then measured under the conditions of a relative refractive index of 1.10.

The inorganic particles for obtaining the surface-coated inorganic particles are at least one selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles. These inorganic particles preferably have an average particle diameter in the range of 0.001 to 100 μm, for example. Preferably it is 0.01-100 micrometers, More preferably, it is the range of 0.05-75 micrometers.
It is preferable that the hydraulic inorganic particles and the pozzolanic active inorganic particles are not yet hydrated (cured), that is, unhydrated.

In the above-mentioned hydraulic inorganic particles, “hydraulic” means “hydraulic” in a narrow sense that a hydration reaction occurs in the presence of water and hardens as a solid, but it is not hydrated only with water, It also means “latent hydraulic” in which a hydration reaction takes place in the presence of a small amount of substance called an irritant and hardens as a solid.

Examples of the hydraulic inorganic particles include narrowly defined hydraulic inorganic particles such as cement and alumina; latent hydraulic inorganic particles such as slag; and the like, and are composed of one or more of these. Also good. Among these, cement and blast furnace slag are preferable, and thereby, the operational effect of the present invention of shortening the kneading time can be more fully exhibited.

Specific examples of the cement include Portland cement (ordinary, early strength, ultra-early strength, low heat, moderate heat, sulfate resistant and low alkali type), 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 heat cement (low heat blast furnace cement, fly ash mixing) Low exothermic type blast furnace cement, cement with high belite content), ultra-high strength cement, cement-based solidified material, eco-cement (cement produced from one or more of municipal waste incineration ash and sewage sludge incineration ash) .

The pozzolanic active inorganic particles mean inorganic particles having pozzolanic activity, and examples thereof include silica fume, fly ash, cinder ash, husk ash, volcanic ash, etc., and one or more of these may be used. it can. Among these, silica fume and fly ash are preferable, and thereby, the effect of the present invention of shortening the kneading time can be more fully exhibited.

The inorganic particles are particularly preferably at least one selected from the group consisting of cement, silica fume, fly ash and slag. As a result, the effect of the present invention of shortening the kneading time can be more fully exhibited. Thus, the form in which the inorganic particles are at least one selected from the group consisting of cement, silica fume, fly ash and slag is one of the preferred forms of the present invention.

In the present invention, the surface-coated inorganic particles in which part or all of the cement surface is coated with an organic dispersant, and part or all of the surface of silica fume, fly ash and / or slag are coated with an organic dispersant. It is particularly preferred to use the surface-coated inorganic particles together. Normally, inorganic particles such as silica fume and fly ash have a small particle size, so when the inorganic particles are used as they are (that is, without being subjected to a coating treatment) for producing a hydraulic composition, the kneading time becomes long. Productivity is not enough. However, if particles obtained by mixing a part or all of the surface of these inorganic particles with an organic dispersant and then mixing such surface-coated inorganic particles are used, when mixed with water, kneading The silica fume cement, fly ash cement, and blast furnace slag cement having a high fluidity can be provided by significantly shortening the time.

The form in which a part or all of the surface of the inorganic particles is coated with the organic dispersant means that the organic dispersant is adsorbed or adhered to the surface of the inorganic particles. Since the organic dispersant has carbon atoms, if the organic dispersant is present in the inorganic particles and the carbon content (carbon concentration) on the surface (or the vicinity of the surface) is improved, the surface of the inorganic particles is organic. It is presumed that the system dispersant is adsorbed or adhered, that is, part or all of the surface of the inorganic particles is coated with the organic dispersant.
In addition, it can be confirmed that the organic dispersant is adsorbed or adhered to the particle surface by, for example, measuring the carbon content (carbon concentration) on the particle surface using X-ray photoelectron spectroscopy or the like. it can.

X-ray photoelectron spectroscopy is an analysis method in which a solid surface is excited with soft X-rays under high vacuum and photoelectrons emitted from the surface are measured (hereinafter referred to as XPS analysis method or XPS). This analysis provides information on the oxidation state and concentration of elements present in the vicinity of a few nanometers near the surface, and the relative concentration of C (carbon) relative to Si (silicon) and Ca (calcium) on the surface can be identified. It is done.

(XPS analysis method)
In the present invention, the relative surface concentration of C with respect to Si and Ca in the surface-coated inorganic particles is measured. The relative surface concentration of C to Si and Ca are counts per vertical axis per second, the horizontal axis XPS chart showing the binding energy, the value of the peak area was divided by the sensitivity coefficient of the C _1s of C _1s, Si Table the peak area of _2p and divided by the sensitivity coefficient of the Si _2p, in total of the value of the peak area was divided by the sensitivity coefficient of the Ca _2p of Ca _2p, a value obtained by dividing, by the following equation (1) Is done.

The peak areas of C _1s , Si _2p and Ca _2p can be measured and calculated by the following procedure.
Measuring apparatus: PHI Quantera SXM manufactured by ULVAC-PKI is used, the X-ray source is AlKα, the beam diameter is 100 μm, and the beam output is 25 W-15 kV.
Sample preparation method: Particle powder as a measurement sample is filled in a SUS φ3 washer, and then fixed with finger pressure using a spatula. It is set on the sample table with a SUS jig. Never use carbon-type jigs such as carbon tape.
Depth direction analysis method: Ar ⁺ ions (2 kV-25 mA) are used to perform edging at a rate of 8 nm / min in terms of SiO ₂ to perform depth direction analysis.
In the measurement of Si _2p , Ca _2p , and C _1s , the path energy is set to 280 eV and the energy step is set to 0.5 eV.
The peak area of Si _2p is calculated by accumulating 14 peaks around 100 eV and removing the background by the Shirley method.
The peak area of Ca _2p is calculated by integrating the peak around 345 to 350 eV 14 times, and then removing the background by the Shirley method.
The peak area of C _1s is calculated by accumulating 14 peaks around 285 eV and removing the background by the Shirley method.
The sensitivity coefficient is a value unique to the measuring apparatus, and the sensitivity coefficients of Si _2p , Ca _2p , and C _1s of the apparatus are 119.676, 597.269, and 87.799, respectively.

When the relative surface concentration of C relative to Si and Ca on the surface of the surface-coated inorganic particles is measured by XPS, the relative surface concentration of C relative to Si and Ca on the particle surface (depth 0 nm) is 0.35 to 0.35. And the relative surface concentration of C having an average depth of 1 to 2 nm from the particle surface is 0.15 to 50. Thereby, kneading | mixing time can be shortened more and it becomes possible to give the hydraulic composition excellent in fluidity | liquidity with sufficient productivity. The lower limit of the relative surface concentration of C with respect to Si and Ca on the particle surface (depth 0 nm) is more preferably 0.4 or more, still more preferably 0.5 or more, and particularly preferably 0.8 or more. The upper limit is more preferably 30 or less, still more preferably 10 or less, particularly preferably 5 or less, and most preferably 3 or less. The lower limit of the relative surface concentration of C having an average depth of 1 to 2 nm from the particle surface is more preferably 0.18 or more, further preferably 0.20 or more, particularly preferably 0.25 or more, and more preferably 0. .3 or more. The upper limit is more preferably 30 or less, still more preferably 10 or less, particularly preferably 5.0 or less, and most preferably 3.0 or less.

The above-mentioned “relative surface concentration of C having an average depth of 1 to 2 nm from the particle surface” means the relative surface concentration of C at a depth of 1 nm from the surface and the relative surface of C at a depth of 2 nm from the surface. Mean value with concentration. The carbon content ratio on the particle surface (depth 0 nm) may have an effect due to surface contamination, but the effect is reduced at a depth of 1 nm or more from the surface, so an organic dispersant is present on the particle surface. It is possible to more accurately confirm that it is adsorbed or adhered.

As a method for confirming the presence of the organic dispersant in the inorganic particles, a solvent such as water or alcohol was added to the particles partially or wholly covered with the organic dispersant and stirred for a predetermined time. Thereafter, the supernatant can be separated by centrifugation or the like, and the supernatant can be dried and analyzed by NMR or the like.

The organic dispersant is not particularly limited, and one or more of the commonly used dispersants for hydraulic inorganic particles (also referred to as water reducing agents) can be used. For example, the following compounds are exemplified.
Lignin sulfonate, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate, polystyrene sulfonate, amino sulfonate (for example, aminoaryl sulfonic acid-phenol-formaldehyde condensate, etc., JP-A-1-113419) A sulfonic acid salt such as a polymer; a polymer having a polyoxyalkylene group and an anionic group (for example, ethylene oxide or the like added to a specific unsaturated alcohol such as 3-methyl-3-buten-1-ol) Copolymer or salt thereof obtained using a monomer component containing an alkenyl ether monomer and an unsaturated carboxylic acid monomer (Japanese Patent Laid-Open Nos. 62-68808 and 10-236858, JP, 2001-220417, A); (meth) acrylic acid poly Copolymers using tylene (propylene) glycol ester or polyethylene (propylene) glycol mono (meth) allyl ether, (meth) allyl sulfonic acid (salt) and (meth) acrylic acid (salt) (JP-A-62-216950) A copolymer obtained by using polyethylene (propylene) glycol ester of (meth) acrylic acid, (meth) allylsulfonic acid (salt) and (meth) acrylic acid (salt) (Japanese Patent Laid-Open No. 1-2226757) A copolymer of polyethylene glycol mono (meth) allyl ether and maleic acid (salt) (see JP-A-4-149056); polyethylene glycol mono (meth) allyl ether, polyethylene glycol mono (meth) Acrylate, (meth) acrylic acid alkyl ester, (meth) Crylic acid (salt) and a copolymer obtained by using (meth) allylsulfonic acid (salt) or p- (meth) allyloxybenzenesulfonic acid (salt) (see JP-A-6-191918); A copolymer of an alkoxypolyalkylene glycol monoallyl ether and maleic anhydride, a hydrolyzate thereof or a salt thereof (see JP-A-5-43288);

A copolymer obtained from a monomer component containing a (alkoxy) polyalkylene glycol mono (meth) acrylic acid ester monomer and a (meth) acrylic acid monomer (see Japanese Patent Publication No. 59-18338); (Meth) acrylic acid ester having a sulfonic acid group and, if necessary, a copolymer or a salt thereof using a monomer copolymerizable therewith (see Japanese Patent Publication No. 62-119147); alkoxy polyalkylene glycol mono An esterification reaction product of a copolymer of allyl ether and maleic anhydride and a polyoxyalkylene derivative having a hydroxyl group at the terminal (see JP-A-6-298555); a polyalkylene glycol monoester monomer; (Meth) acrylic acid monomer, unsaturated dicarboxylic acid monomer and / or (meth) allylsulfonic acid monomer Copolymers obtained by use (see JP-A-7-223852); styrene sulfonic acid, sulfoalkyl (meth) acrylate, 2-acrylamido-2-methylpropanesulfonic acid and / or hydroxyalkyl (meth) acrylate monophosphoric acid A copolymer obtained by using an ester, an (alkoxy) polyalkylene glycol mono (meth) acrylate, and an unsaturated carboxylic acid monomer or a salt thereof (see JP-A-11-79811); (alkoxy) A copolymer obtained by using a polyalkylene glycol monovinyl ether monomer, an unsaturated carboxylic acid monomer and (hydroxy) alkyl (meth) acrylate (see JP 2004-307590 A); (alkoxy) poly Alkylene glycol mono (meth) acrylate, Copolymer obtained by using acid monoester monomer and phosphoric acid diester monomer or a salt thereof (see JP 2006-52381 A); unsaturated (poly) alkylene glycol ether monomer And a copolymer of an unsaturated monocarboxylic acid monomer (see JP 2002-121055 A and JP 2002-121056 A);

Among the above organic dispersants, sulfonic acid dispersants such as lignin sulfonate and naphthalene sulfonate formalin condensate, and polycarboxylic acid dispersants are preferable. More preferably, it is preferable to use at least a polycarboxylic acid-based dispersant from the viewpoint of excellent dispersibility and excellent adsorptivity to the surface of hydraulic inorganic particles and pozzolanic active inorganic particles.

The polycarboxylic acid-based dispersant is preferably a dispersant containing a polymer having a carboxyl group and / or a structure portion of a salt thereof (polycarboxylic acid-based polymer). Among them, from the viewpoint of being superior in dispersion performance. Those containing polyalkylene glycol are preferred. More preferably, the organic dispersant includes a polycarboxylic acid polymer containing polyalkylene glycol. Thus, the form in which the organic dispersant contains a polycarboxylic acid polymer containing polyalkylene glycol is one of the preferred forms of the present invention. Such a polycarboxylic acid polymer is particularly highly adsorbable on the surface of the inorganic particles, and can exhibit sufficient dispersibility after surface coating.

The polyalkylene glycol is preferably formed of one or more of 2 to 18 carbon oxyalkylene groups. When two or more types of oxyalkylene groups are present, the addition form may be any addition form such as random addition, block addition, and alternate addition. As carbon number of the said oxyalkylene group, 2-8 are preferable, More preferably, it is 2-4. More preferably, it is 2, that is, the polyalkylene glycol is preferably polyethylene glycol.

Specific examples of the oxyalkylene group having 2 to 18 carbon atoms include oxyethylene group, oxypropylene, oxybutylene group, oxyisobutylene group, oxybutene group (1-butene oxide, 2-butene oxide, etc.) and the like. Of these, an oxyethylene group and an oxypropylene group are preferable. More preferably, the main component is an oxyethylene group.
An oxyethylene group is mainly composed of ethylene oxide when the polyalkylene glycol is formed of two or more oxyalkylene groups in the number of moles of all alkylene oxides forming the oxyalkylene group. Means that. Thereby, the balance between the hydrophilicity and the hydrophobicity of the polycarboxylic acid polymer becomes better, and the effect exhibited by the polymer is more fully exhibited. Specifically, the oxyethylene group is preferably 50 to 100 mol% in 100 mol% of all oxyalkylene groups constituting the polyalkylene glycol. More preferably, it is 60-100 mol%, More preferably, it is 70-100 mol%, Especially preferably, it is 80-100 mol%, Most preferably, it is 90-100 mol%.

In the polyalkylene glycol, the average number of repeating alkylene glycol (oxyalkylene group) (average number of added moles) is preferably, for example, 2 to 300. More preferably, it is a number of 5 to 300. More preferably, it is 10-150, Most preferably, it is 20-100, More preferably, it is 23-75, Most preferably, it is 25-75.

The polycarboxylic acid dispersant and the polyalkylene glycol in the polycarboxylic acid polymer may be present alone but are preferably included as part of the polymer structure. Specifically, the organic dispersant preferably includes a polycarboxylic acid polymer having a polyalkylene glycol chain.

Examples of the polycarboxylic acid polymer containing the polyalkylene glycol include a structural unit (A) derived from an unsaturated polyalkylene glycol monomer (a) and an unsaturated carboxylic acid monomer (b). A polymer having the derived structural unit (B) is preferred. Such a polymer is superior in the adsorptivity to the hydraulic inorganic particles and the pozzolanic active inorganic particles and the particle dispersibility after the adsorption (that is, after the surface coating), so that the kneading time for obtaining the hydraulic composition is further increased. The fluidity of the obtained hydraulic composition can be further improved. More preferably, it is a polymer obtained by polymerizing a monomer component containing an unsaturated polyalkylene glycol monomer (a) and an unsaturated carboxylic acid monomer (b). Each monomer contained in the monomer component can be used alone or in combination of two or more.
In addition, each structural unit means the structure where the polymerizable double bond (carbon-carbon double bond) which each monomer has became a single bond.
Hereinafter, the unsaturated polyalkylene glycol monomer (a) is also referred to as “monomer (a)”, the unsaturated carboxylic acid monomer (b) is also referred to as “monomer (b)”, A polymer having the structural unit (A) derived from the monomer (a) and the structural unit (B) derived from the monomer (b) is also referred to as “copolymer (I)”.

<Unsaturated polyalkylene glycol monomer (a)>
The unsaturated polyalkylene glycol monomer (a) may be any monomer having a polymerizable unsaturated group and a polyalkylene glycol chain.
The polyalkylene glycol chain is preferably composed of, for example, one or more oxyalkylene groups having 2 to 18 carbon atoms. When two or more types of oxyalkylene groups are present, the addition form may be any addition form such as random addition, block addition, and alternate addition. As carbon number of the said oxyalkylene group, 2-8 are preferable, More preferably, it is 2-4. More preferably, it is 2, that is, the polyalkylene glycol chain is preferably a polyethylene glycol chain.
Specific examples and preferred embodiments of the oxyalkylene group having 2 to 18 carbon atoms are as described above.

In the polyalkylene glycol chain, the average number of repeating alkylene glycols (oxyalkylene groups) (average number of added moles) is preferably, for example, 2 to 300. More preferably, it is a number of 5 to 300. By being in such a range, since the polymerization reactivity of the monomer (a) and the hydrophilicity of the copolymer (I) become more sufficient, the effects of the present invention can be fully exhibited. Is possible. The average added mole number is more preferably 10 to 150, particularly preferably 20 to 100, more preferably 23 to 75, and most preferably 25 to 75.

The unsaturated polyalkylene glycol monomer (a) is particularly preferably represented by the following general formula (1). Thus, the polycarboxylic acid polymer is composed of the structural unit (A) derived from the unsaturated polyalkylene glycol monomer (a) represented by the following general formula (1), and the unsaturated carboxylic acid single monomer. The form which is a polymer having the structural unit (B) derived from the body (b) is one of the preferred forms of the present invention. As such a polymer, a polymer obtained by polymerizing monomer components including the monomer (a) and the monomer (b) represented by the following general formula (1) is more preferable.

In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group. p represents an integer of 0 to 2. q represents 0 or 1; AO is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n is an average addition mole number of the oxyalkylene group represented by AO, and is a number of 2 to 300. R ³ represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms.

In the general formula (1), the polyalkylene glycol chain represented by-(AO) _n- is as described above.
In the general formula (1), R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group, and p is 0, 1 or 2. Therefore, the alkenyl group represented by “C (R ¹ ) H═C (R ² ) — (CH ₂ ) _p —” corresponds to an alkenyl group having 2 to 6 carbon atoms. Preferably, it is 3-5.
Examples of the alkenyl group represented by “C (R ¹ ) H═C (R ² ) — (CH ₂ ) _p —” include, for example, vinyl group, allyl group, methallyl group, 3-butenyl group, 3-methyl And a -3-butenyl group. Among these, a vinyl group, an allyl group, a methallyl group, and a 3-methyl-3-butenyl group are preferable.
As R ¹ and R ² , it is preferable that R ¹ is a hydrogen atom and R ² is a methyl group, and such a form is one of the preferred embodiments of the present invention.

In the general formula (1), ^{R 3} represents a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. When R ³ represents a hydrocarbon group, the number of carbon atoms (number of carbon atoms) is preferably 1 to 12, more preferably 1 to 8, from the viewpoint of further improving the hydrophilicity of the copolymer (I). More preferably, it is 1-4, particularly preferably 1-3, and most preferably 1-2.
As the hydrocarbon group, for example, an alkyl group (straight chain, branched chain or cyclic), a phenyl group, an alkyl-substituted phenyl group, an alkenyl group, an alkynyl group, an aryl group and the like are preferable. Among these, an alkyl group (straight chain, branched chain or cyclic) is more preferable. Especially, a C1-C12 linear or branched alkyl group and a C3-C12 alicyclic alkyl group are preferable, More preferably, a C1-C4 linear or branched alkyl group is preferable. A alicyclic alkyl group having 3 to 4 carbon atoms, more preferably a linear or branched alkyl group having 1 to 3 carbon atoms, and an alicyclic alkyl group having 3 carbon atoms.

R ³ is particularly preferably a hydrogen atom, a linear or branched alkyl group having 1 to 3 carbon atoms, or an alicyclic alkyl group having 3 carbon atoms, and more preferably a hydrogen atom, a methyl group or ethyl. A group, most preferably a hydrogen atom.

In the general formula (1), q represents 0 or 1, and when q = 0, the monomer (a) is a monomer having an ether structure (also referred to as an ether monomer). Become. When q = 1, the monomer (a) is a monomer having an ester structure (also referred to as an ester monomer). Among these, it is preferable that q = 0, that is, the monomer (a) is an ether-based monomer, which makes it possible to further improve the dispersion performance.

When the monomer (a) is an ether monomer, a specific example of the monomer includes an unsaturated polyalkylene glycol ether monomer. Specifically, an unsaturated alcohol polyalkylene glycol adduct, that is, a compound having a structure in which a polyalkylene glycol chain is added to an alcohol having an unsaturated group (referred to as an unsaturated alcohol) is preferable. Such a compound can be obtained, for example, by adding an alkylene glycol (also referred to as alkylene oxide) to an unsaturated alcohol.

The unsaturated polyalkylene glycol ether monomer is particularly preferably the following general formula (2):

(In the formula, R ¹ and R ² are the same or different and represent a hydrogen atom or a methyl group. AO is the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. N is a group represented by AO. The average added mole number of the oxyalkylene group is 2 to 300. X represents a divalent alkylene group having 1 to 2 carbon atoms or a direct bond, and R ³ represents a hydrogen atom or Represents a hydrocarbon group having 1 to 18 carbon atoms.)

In the general formula (2), R ¹ , R ² , AO, n, and R ³ are the same as the symbols in the general formula (1).
In the general formula (2), X represents a divalent alkylene group having 1 to 2 carbon atoms or a direct bond. When X represents a direct bond, it has a form in which a carbon atom bonded to X in the general formula (2) and an oxygen atom are directly bonded. Among these, X is preferably a C 1-2 divalent alkylene group. That is, a methylene group or an ethylene group is preferable.

Examples of the unsaturated alcohol polyalkylene glycol adduct represented by the general formula (2) include polyethylene glycol allyl ether, polyethylene glycol methallyl ether, (poly) ethylene glycol 3-methyl-3-butenyl ether, (poly ) Ethylene glycol tetraethylene glycol monovinyl ether, (poly) ethylene (poly) propylene glycol allyl ether, (poly) ethylene (poly) propylene glycol methallyl ether, (poly) ethylene (poly) propylene glycol 3-methyl-3-butenyl Ether, (poly) ethylene (poly) propylene glycol tetraethylene glycol monovinyl ether, (poly) ethylene (poly) butylene glycol allyl ether, (poly) ethylene (poly Butylene glycol methallyl ether, (poly) ethylene (poly) butylene glycol 3-methyl-3-butenyl ether, (poly) ethylene (poly) butylene glycol tetraethylene glycol monovinyl ether, methoxypolyethylene glycol allyl ether, methoxypolyethylene glycol methallyl ether , Methoxy (poly) ethylene glycol 3-methyl-3-butenyl ether, methoxy (poly) ethylene glycol tetraethylene glycol monovinyl ether, methoxy (poly) ethylene (poly) propylene glycol allyl ether, methoxy (poly) ethylene (poly) Propylene glycol methallyl ether, methoxy (poly) ethylene (poly) propylene glycol 3-methyl-3-butenyl ether, Xyl (poly) ethylene (poly) propylene glycol tetraethylene glycol monovinyl ether, methoxy (poly) ethylene (poly) butylene glycol allyl ether, methoxy (poly) ethylene (poly) butylene glycol methallyl ether, methoxy (poly) ethylene (poly) Butylene glycol 3-methyl-3-butenyl ether, methoxy (poly) ethylene (poly) butylene glycol tetraethylene glycol monovinyl ether, and the like are suitable. In the present invention, it is particularly preferable to use one or more of these as the monomer (a) giving the structural unit (A).

When the monomer (a) is an ether monomer such as the unsaturated polyalkylene glycol ether monomer, the monomer (a) can be produced by various methods. It is preferable to obtain by any one of the following production methods 1) to 3).
1) When R ³ in the general formula (1) is a hydrogen atom, for example, a predetermined mole addition of an alkylene oxide having 2 to 18 carbon atoms to an unsaturated alcohol in the presence of an alkali catalyst and / or an acid catalyst To obtain the monomer (a).
The unsaturated alcohol is preferably, for example, one or more alcohols having an alkenyl group having 2 to 6 carbon atoms such as allyl alcohol, methallyl alcohol, and 3-methyl-3-buten-1-ol. It is.
Examples of the alkali catalyst include potassium hydroxide and sodium hydroxide, and examples of the acid catalyst include boron trifluoride and tin tetrachloride.

2) When R ³ in the general formula (1) is an alkyl group having 1 to 18 carbon atoms, the compound obtained by the production method 1) obtained by adding a predetermined mole of an alkylene oxide to an unsaturated alcohol, A method of obtaining the monomer (a) by reacting an alkyl halide having 1 to 18 carbon atoms such as methyl chloride in the presence of an alkali catalyst.

3) When R ³ in the general formula (1) is an alkyl group having 1 to 18 carbon atoms, contrary to the production method 2), the alcohol having 1 to 18 carbon atoms is substituted with an alcohol having 2 to 18 carbon atoms. A method of obtaining a monomer (a) by further reacting a alkenyl halide having 2 to 6 carbon atoms with a compound obtained by adding a predetermined mole of an alkylene oxide in the presence of an alkali catalyst.
In addition, as for C1-C18 alcohol, C1-C18 alcohols, such as methanol and ethanol, etc. are mentioned.
Examples of the alkenyl halide having 2 to 6 carbon atoms include allyl chloride and methallyl chloride.

When the monomer (a) is an ester monomer, specific examples of the monomer include unsaturated polyalkylene glycol ester monomers, that is, unsaturated groups and polyalkylene glycol chains are esters. Examples thereof include compounds having a structure bonded through a bond. Among such compounds, unsaturated carboxylic acid polyalkylene glycol ester compounds are preferable, and (alkoxy) polyalkylene glycol mono (meth) acrylate and (hydroxy) polyalkylene glycol mono (meth) acrylate are more preferable.

As said (alkoxy) polyalkylene glycol mono (meth) acrylate, the alkoxy polyalkylene glycol which added 1-25 mol of C2-C18 alkylene oxide groups to alcohol is suitable, for example. More preferably, it is an esterified product of an alkoxy polyalkylene glycol mainly composed of ethylene oxide and (meth) acrylic acid.

Examples of the alcohols include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 1-hexanol, and 2-hexanol. C1-C30 aliphatic alcohols such as 3-hexanol, octanol, 2-ethyl-1-hexanol, nonyl alcohol, lauryl alcohol, cetyl alcohol and stearyl alcohol; C3-C30 fats such as cyclohexanol Cyclic alcohols; (meth) allyl alcohol, 3-buten-1-ol, C3-C30 unsaturated alcohols such as 3-methyl-3-buten-1-ol; and the like.

Specific examples of the esterified product include the following (alkoxy) polyethylene glycol (poly) (alkylene glycol having 2 to 4 carbon atoms) (meth) acrylic acid esters, (hydroxy) polyethylene glycol (poly) (2 carbon atoms). ~ 4 alkylene glycol) (meth) acrylic acid esters and the like are preferred.

Hydroxy polyethylene glycol mono (meth) acrylate, methoxy polyethylene glycol mono (meth) acrylate, hydroxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, methoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, Hydroxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, methoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, hydroxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meta) ) Acrylate, Methoxy {Polyethylene glycol (poly) propylene glycol (poly) butylene glycol } Mono (meth) acrylate, ethoxy polyethylene glycol mono (meth) acrylate, ethoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, ethoxy {polyethylene glycol (poly) butylene glycol} mono (meth) acrylate, ethoxy { Polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate, propoxypolyethyleneglycol mono (meth) acrylate, propoxy {polyethyleneglycol (poly) propyleneglycol} mono (meth) acrylate, propoxy {polyethyleneglycol (poly ) Butylene glycol} mono (meth) acrylate, propoxy {polyethylene glycol (poly) propylene glycol (Poly) butylene glycol} mono (meth) acrylate, butoxypolyethylene glycol mono (meth) acrylate, butoxy {polyethylene glycol (poly) propylene glycol} mono (meth) acrylate, butoxy {polyethylene glycol (poly) butylene glycol} mono (Meth) acrylate, butoxy {polyethylene glycol (poly) propylene glycol (poly) butylene glycol} mono (meth) acrylate, and the like.

<Unsaturated carboxylic acid monomer (b)>
The unsaturated carboxylic acid monomer (b) is not particularly limited as long as it is a monomer having a polymerizable unsaturated group and a carboxyl group which is an adsorbing group and / or a structural portion of a salt thereof. An unsaturated monocarboxylic acid monomer (b-1) such as a (meth) acrylic acid monomer is preferred. Specifically, one or more of acrylic acid, methacrylic acid, crotonic acid, and these monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts can be used. Among these, from the viewpoint of copolymerization, (meth) acrylic acid and / or a salt thereof is preferable, and acrylic acid and / or a salt thereof is more preferable.

Examples of the monovalent metal atom that constitutes the monovalent metal salt include lithium, sodium, and potassium. Examples of the divalent metal atom that constitutes the divalent metal salt include calcium and magnesium. . Examples of the organic amine group constituting the organic amine salt include alkanolamine groups such as monoethanolamine group, diethanolamine group and triethanolamine group; alkylamine groups such as monoethylamine group, diethylamine group and triethylamine group; ethylenediamine And polyamine groups such as a triethylenediamine group. When the monomer (b) is a salt, it is preferably an ammonium salt or a monovalent metal salt. A monovalent metal salt is more preferable, an ammonium salt, a sodium salt or a potassium salt is more preferable, and a sodium salt is particularly preferable.

In the copolymer (I), the structural ratio ((A) / (B)) of the structural unit (A) derived from the monomer (a) and the structural body (B) derived from the monomer (b) Is preferably 55 to 90/10 to 45 (mass ratio). More preferably, it is 70-90 / 10-30, and it becomes possible to exhibit the effect of this invention more fully by this. Thus, the structural ratio of the structural unit (A) derived from the unsaturated polyalkylene glycol monomer (a) and the structural unit (B) derived from the unsaturated carboxylic acid monomer (b) ((A) / The form in which (B)) is 70 to 90/10 to 30 (mass ratio) is one of the preferred forms of the present invention. More preferably, it is 75-85 / 15-25, Most preferably, it is 79-85 / 15-21, Most preferably, it is 80-85 / 15-20.
In particular, when one or more unsaturated monocarboxylic acid monomers (b-1) are used as the monomer (b), the structural unit (A) and the unsaturated monocarboxylic acid are used. The structural ratio ((A) / (B-1)) to the structural unit (B-1) derived from the acid monomer (b-1) is 70 to 90/10 to 30 (mass ratio). This makes it possible to exhibit the effects of the present invention more fully. More preferably, it is 75-85 / 15-25, More preferably, it is 79-85 / 15-21, Most preferably, it is 80-85 / 15-20.

In this specification, when calculating the proportion of the structural unit (B) derived from the unsaturated carboxylic acid monomer (b), the structural unit (B) is a completely neutralized monomer (salt). It shall be calculated as a structural unit derived from. When calculating the ratio of the unsaturated carboxylic acid monomer (b), it is assumed that the monomer (b) is a completely neutralized monomer (salt). For example, when using acrylic acid as the monomer (b) and completely neutralizing with sodium hydroxide in the polymerization reaction, it is assumed that sodium acrylate is used as the monomer (b). Calculate. In the case where maleic acid is used as the monomer (b) and complete neutralization with sodium hydroxide in the polymerization reaction, disodium maleate is used as the monomer (b). ).

The unsaturated carboxylic acid monomer (b) also includes maleic acid, fumaric acid, itaconic acid, and unsaturated dicarboxylic acids such as monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts. It may be a system monomer (b-2), and one or more of these can be used. The salt is as described above. Among these unsaturated dicarboxylic acid monomers (b-2), maleic acid and / or a salt thereof is preferable from the viewpoint of copolymerization.

The copolymer (I) also includes a monomer (a), an unsaturated monocarboxylic acid monomer (b-1), and an unsaturated dicarboxylic acid monomer (b-2). A copolymer obtained by polymerizing the components is also suitable. That is, the copolymer is preferably a copolymer containing the structural unit (A), the structural unit (B-1), and the structural unit (B-2) derived from the unsaturated dicarboxylic acid monomer (b-2). . In this case, the constituent ratio of the constituent units ((A) / (B-1) / (B-2)) is preferably 55 to 85/10 to 30/5 to 15 (mass ratio). Thus, the unsaturated carboxylic acid monomer (b) is an unsaturated monocarboxylic acid monomer (b-1) and an unsaturated dicarboxylic acid monomer (b-2), and is unsaturated. The structural unit (A) derived from the polyalkylene glycol monomer (a), the structural unit (B-1) derived from the unsaturated monocarboxylic acid monomer (b-1), and the unsaturated dicarboxylic acid based single The structural ratio ((A) / (B-1) / (B-2)) to the structural unit (B-2) derived from the monomer (b-2) is 55 to 85/10 to 30/5 to 15 ( The mass ratio) is also one of the preferred embodiments of the present invention. More preferably, it is 60-85 / 10-25-25 / 5, More preferably, it is 65-80 / 15-25 / 5-10.

<Other monomers>
The monomer component may also be one or two unsaturated monoacrylate monomers (c) as monomers copolymerizable with the monomer (a) and the monomer (b). It may contain more than seeds. That is, the copolymer (I) may further contain a structural unit (C) derived from the unsaturated monocarboxylic acid ester monomer (c). By further including the structural unit (C) derived from the unsaturated monoacrylate monomer (c), fluidity can be expected to be maintained for a certain period of time.

As the unsaturated monoacrylate monomer (c), for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like are preferable. Among these, methyl acrylate, ethyl acrylate and / or butyl acrylate are more preferable, and butyl acrylate is still more preferable.

When the copolymer (I) further contains a structural unit (C) derived from the unsaturated monocarboxylic acid ester monomer (c), the structural unit (A), the structural unit (B), and the structural unit ( The composition ratio ((A) / (B) / (C)) with C) is preferably 65 to 84/10 to 30/1 to 5 (mass ratio). Thus, the copolymer further contains a structural unit (C) derived from an unsaturated monocarboxylic acid ester monomer (c), and a structural unit derived from an unsaturated polyalkylene glycol monomer (a) (A ), The structural unit (B) derived from the unsaturated carboxylic acid monomer (b) and the structural unit (C) derived from the unsaturated monocarboxylic acid ester monomer (c) ((A ) / (B) / (C)) is also from 65 to 84/10 to 30/1 to 5 (mass ratio), which is also a preferred embodiment of the present invention. More preferably, it is 70-83 / 15-25 / 2-5.

The copolymer (I) may also contain structural units derived from one or more of other copolymerizable monomers. Such a structural unit is preferably 30% by mass or less in 100% by mass of all the structural units constituting the copolymer (I). More preferably, it is 20 mass% or less, More preferably, it is 10 mass% or less.

Examples of the other copolymerizable monomers include various diesters; diamides; half amides; (poly) alkylene glycols exemplified in International Publication No. 2014/010572 [0041] to [0042]. Di (meth) acrylates; polyfunctional (meth) acrylates; (poly) alkylene glycol dimaleates; unsaturated sulfonic acids and salts thereof; amides such as methyl (meth) acrylamide; vinyl aromatics; alkanediol mono (Meth) acrylates; dienes; unsaturated amides; unsaturated cyanides; unsaturated esters; unsaturated amines; divinyl aromatics; cyanurates;

The copolymerization reaction can be performed using a polymerization initiator, and can be performed by a method such as polymerization in a solvent or bulk polymerization. The amount of each monomer used in the copolymerization reaction is such that the proportion of each structural unit in the polymer is in the above-described range, taking into account the reaction rate during the copolymerization reaction of each monomer, It is preferable to set appropriately.

The polymerization in the solvent can be carried out batchwise or continuously. The solvent used in this case is water; lower alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol; benzene, toluene, xylene, cyclohexane, Aromatic or aliphatic hydrocarbons such as n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone are preferred. These may be used alone or in combination of two or more. From the solubility of the raw material monomer and the resulting copolymer (I), and convenience during use of the copolymer (I), it is selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms. It is preferable to use at least one selected from the above. In that case, methyl alcohol, ethyl alcohol, isopropyl alcohol and the like are particularly effective among the lower alcohols having 1 to 4 carbon atoms.

In the case of carrying out the aqueous solution polymerization, as a radical polymerization initiator, a water-soluble polymerization initiator, for example, a persulfate such as ammonium persulfate, sodium persulfate, potassium persulfate; hydrogen peroxide; 2,2'-azobis- Azoamidine compounds such as 2-methylpropionamidine hydrochloride, cyclic azoamidine compounds such as 2,2′-azobis-2- (2-imidazolin-2-yl) propane hydrochloride, and azonitriles such as 2-carbamoylazoisobutyronitrile Water-soluble azo initiators such as compounds are used. In this case, alkali metal sulfites such as sodium hydrogen sulfite, metabisulphite, sodium hypophosphite, Fe (B) salts such as molle salt, hydroxymethanesulfine Acid sodium dihydrate, hydroxylamine hydrochloride, thiourea, L-ascorbic acid (salt), erythorbium It can also be used in combination accelerator acid (salt) and the like.

For polymerization using lower alcohols, aromatic hydrocarbons, aliphatic hydrocarbons, ester compounds or ketone compounds as solvents, peroxides such as benzoyl peroxide and lauroyl peroxide; hydroperoxides such as cumene hydroperoxide; azobis An azo compound such as isobutyronitrile is used as a polymerization initiator. In this case, an accelerator such as an amine compound can be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from the above-mentioned various polymerization initiators or combinations of polymerization initiators and accelerators. The polymerization temperature is appropriately determined depending on the solvent to be used and the polymerization initiator, but is usually 0 to 120 ° C.

The bulk polymerization uses a peroxide such as benzoyl peroxide or lauroyl peroxide as a polymerization initiator; a hydroperoxide such as cumene hydroperoxide; an azo compound such as azobisisobutyronitrile, and the like, at a temperature of 50 to 200 ° C. Done in

The method of charging each monomer into the reaction vessel is not particularly limited. The method of initially charging the entire amount into the reaction vessel at once, the method of dividing or continuously charging the entire amount into the reaction vessel, and the initial charging into the reaction vessel. Any method may be used in which the remainder is divided or continuously charged into the reaction vessel. Specific examples of a suitable charging method include the following methods (1) to (4).
(1) A method of continuously charging all of the monomers into the reaction vessel.
(2) A method in which all of the monomer (a) is initially charged into the reaction vessel and all other monomers are continuously charged into the reaction vessel.
(3) A method in which a part of the monomer (a) is initially charged into the reaction vessel, and the remainder of the monomer (a) and all other monomers are continuously charged into the reaction vessel.
(4) A part of the monomer (a) and a part of the other monomer are initially charged into the reaction vessel, and the remainder of the monomer (a) and the rest of the other monomer are respectively added to the reaction vessel. A method of splitting into several times alternately.
Furthermore, by changing the charging rate of each monomer into the reaction vessel during the reaction continuously or stepwise, the charging mass ratio of each monomer per unit time can be changed continuously or stepwise. You may make it synthesize | combine the mixture of the copolymer from which the ratio of each structural unit in a polymer differs in a polymerization reaction. The radical polymerization initiator may be charged into the reaction vessel from the beginning, may be dropped into the reaction vessel, or may be combined according to the purpose.

Further, a chain transfer agent can be used in combination for adjusting the molecular weight of the obtained copolymer (I). Chain transfer agents include mercaptoethanol, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, 2-mercaptoethanesulfonic acid and other thiol chain transfer agents; isopropyl alcohol and other secondary alcohols; phosphorous acid Hypophosphorous acid and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionic acid, metabisulfite and salts thereof (sodium sulfite, sodium hydrogen sulfite, dithione) Commonly used hydrophilic chain transfer agents such as lower oxides of sodium acid, sodium metabisulfite and the like and salts thereof can be used.

The copolymer (I) obtained as described above can be used as it is as a surface coating agent for hydraulic inorganic particles or pozzolanic active inorganic particles, but if necessary, the copolymer (I). May be used after neutralizing with an alkaline substance. As the alkaline substance, inorganic salts such as hydroxides or carbonates of monovalent metals or divalent metals; ammonia; organic amines are suitable. Further, after the reaction is completed, the concentration can be adjusted if necessary.

The weight average molecular weight (Mw) of the polycarboxylic acid-based copolymer is determined based on the binding property (adsorbability) to the hydraulic inorganic particles and the pozzolanic active inorganic particles, the aggregating action of these inorganic particles, and the resulting hydraulic composition. Considering the fluidity retention of the material, it is preferable that the weight average molecular weight (Mw) is 3000 to 500,000. More preferably, it is 5000-300,000, More preferably, it is 7000-200,000, Most preferably, it is 8000-100,000.
The weight average molecular weight of the polymer can be measured, for example, by gel permeation chromatography (also referred to as GPC) using polyethylene glycol as a standard substance under the following measurement conditions.

(GPC measurement conditions)
Apparatus: Waters Alliance (2695), manufactured by Waters
Analysis software: Waters, Empor professional + GPC option column: Tosoh, TSK guard column SWXL + TSKgel G4000SWXL + G3000SWXL + G2000SWXL
Detector: differential refractometer (RI) detector (Waters 2414, manufactured by Waters)
Eluent: 115.6 g of sodium acetate trihydrate dissolved in a mixed solvent of 10999 g of water and 6001 g of acetonitrile, and further adjusted to pH 6.0 with acetic acid, a standard substance for preparing a solution calibration curve: polyethylene glycol [peak top molecular weight (Mp 300000, 200000, 107000, 50000, 27700, 11840, 6450, 1470]
Calibration curve: Created by cubic equation based on Mp value and elution time of polyethylene glycol Flow rate: 1.0 mL / min
Column temperature: 40 ° C
Measurement time: 45 minutes Sample solution injection amount: 100 μL (eluent preparation solution with sample concentration of 0.5 mass%)

The surface-coated inorganic particles of the present invention also have a relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant on the particle surface (depth 0 nm) is 0.6. 10 to 10 is preferable. Thereby, the kneading time can be remarkably shortened, and the effect of the present invention that a hydraulic composition excellent in fluidity can be provided with high productivity can be more sufficiently exhibited. More preferably, it is 0.7-10, More preferably, it is 0.8-8, Especially preferably, it is 0.9-7, More preferably, it is 1.0-6, Most preferably, it is 1.1-5. Furthermore, the relative surface concentration of carbon (C) having an average depth of 1 to 2 nm from the particle surface per unit amount of the organic dispersant obtained by the same method is preferably 0.2 to 5. It is. Thereby, it becomes possible to fully exhibit the effect of this invention. More preferably, it is 0.2-4, More preferably, it is 0.25-3, Especially preferably, it is 0.3-3, More preferably, it is 0.35-2.5.

Here, “the relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant” is a value obtained by the following method.
1. First, organic dispersion present in surface-coated inorganic particles (that is, hydraulic inorganic particles and / or pozzolanic active inorganic particles in which part or all of the surface is coated with an organic dispersant). Determine the amount of agent. This “amount of the organic dispersant present in the surface-coated inorganic particles” means an ignition loss rate at 150 ° C. (this is expressed by (p)) obtained by heating the surface-coated inorganic particles in an electric furnace. ) And the ignition loss rate at 450 ° C. (this is defined as (q)) (= p−q). The ignition loss rate at each temperature here means the mass residual rate (mass%) after heating at each temperature.
2. Next, the XPS of the surface-coated inorganic particles was measured to determine the value of the relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) (this is defined as (x)). Value of relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) by measuring XPS of inorganic particles after heating surface-coated inorganic particles in an electric furnace and heating at 550 ° C. for 3 hours (This is defined as (y)), and the difference between these (= xy) is calculated.
3. Divide the relative surface concentration difference (xy) determined in 2 above by the amount of organic dispersant (pq) present in the surface-coated inorganic particles determined in 1 above. Thus, the value obtained by “(xy) / (pq)” is expressed as “relative surface concentration of carbon (C) relative to silicon (Si) and calcium (Ca) per unit amount of organic dispersant ( z) ".

Particularly in the present invention, when the relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant on the particle surface is measured by XPS, the relative surface of carbon (C) It is preferable that the concentration is 0.6 to 10 and the relative surface concentration of carbon (C) having an average depth of 1 to 2 nm from the particle surface is 0.2 to 5. As a result, the kneading time can be remarkably shortened, and the operational effect of the present invention that can provide a hydraulic composition excellent in fluidity with high productivity can be further exhibited.

The surface-coated inorganic particles of the present invention preferably have a degree of hydration of 0.1 or less. Thereby, hydraulic particles having high hydration activity can be obtained without impairing the hydration characteristics of the hydraulic inorganic particles, and the effects of the present invention can be more fully exhibited. More preferably, it is 0.07 or less, More preferably, it is 0.04 or less. The lower limit of the hydration degree is preferably 0. That is, the degree of hydration is preferably 0 to 0.1, more preferably 0 to 0.07, and still more preferably 0 to 0.04.

In the present specification, “degree of hydration” means a value measured by the following method.
Surface-coated inorganic particles (that is, hydraulic inorganic particles and / or pozzolanic active inorganic particles whose surface is partially or entirely coated with an organic dispersant) are heated in an electric furnace, and 450 The difference (= q−r) between the ignition loss rate at ℃ (this is (q)) and the ignition loss rate at 550 ° C. (this is (r)) is defined as the degree of hydration.
Here, the ignition loss rate at each temperature means the mass residual rate (mass%) after heating at each temperature.

(Hydraulic inorganic particles)
The present invention is also hydraulic inorganic particles containing the surface-coated inorganic particles of the present invention described above. Such hydraulic inorganic particles include, for example, those containing hydraulic inorganic particles and / or pozzolanic active inorganic particles whose surfaces are not coated together with the surface-coated inorganic particles. In this case, the surface-coated inorganic particles are preferably 2% by mass or more, more preferably 5% by mass with respect to the total amount of inorganic particles of 100% by mass, in order to more fully express the effect of the surface-coated inorganic particles. % Or more, more preferably 10% by mass or more, particularly preferably 20% by mass or more, more preferably 30% by mass or more, and most preferably 100% by mass.

In particular, when the surface-coated inorganic particles are silica fume, the surface-coated inorganic particles are contained in an amount of 2 to 15% by mass with respect to 100% by mass of the total amount of the surface-coated inorganic particles and the inorganic particles whose surface is not coated. It is preferable that 5-10 mass% is contained.
When the surface-coated inorganic particles are fly ash or slag, the surface-coated inorganic particles are 10 to 70% by mass with respect to 100% by mass of the total amount of the surface-coated inorganic particles and the inorganic particles whose surface is not coated. It is preferably contained, more preferably 20 to 60% by mass, and still more preferably 30 to 50% by mass.

When the surface-coated inorganic particles are narrowly defined hydraulic inorganic particles (this surface-coated inorganic particles are also referred to as “surface-coated hydraulic inorganic particles”), silica fume or fly ash whose surface is not coated on the surface-coated inorganic particles , Slag can be mixed.
In this mixed system, when the inorganic particles whose surface is not coated are silica fume, the surface-coated hydraulic inorganic material is 100% by mass with respect to the total amount of the surface-coated hydraulic inorganic particles and the inorganic particles whose surface is not coated. The particles are preferably contained in an amount of 2 to 15% by mass, and more preferably 5 to 10% by mass.
In the above mixed system, when the inorganic particles whose surface is not coated are fly ash and slag, the surface is based on the total amount of 100% by mass of the surface-coated hydraulic inorganic particles and the inorganic particles whose surface is not coated. The coated hydraulic inorganic particles are preferably contained in an amount of 10 to 70% by mass, more preferably 20 to 60% by mass, and still more preferably 30 to 50% by mass.

[Method for producing surface-coated inorganic particles]
In the surface-coated inorganic particles of the present invention, at least one inorganic particle selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles is dispersed in a solvent containing an organic dispersant, and then the solvent is retained. What is obtained by the manufacturing method including the process of leaving and pulverizing is preferable, and such a manufacturing method is one of this invention. In addition, the said manufacturing method may further include the other process (for example, washing | cleaning process etc.) employ | adopted by a normal manufacturing means.

In the production method, first, the inorganic particles are added to an organic dispersant and a solvent and dispersed in a solvent until a slurry is formed (also referred to as a dispersion step). The dispersing means is not particularly limited, and it is preferable to use a commonly used technique such as stirring (kneading).
The inorganic particles are as described above.

The said solvent should just contain the organic type dispersing agent and the said inorganic particle can disperse | distribute. For example, it is preferable to contain an organic solvent or water. Thus, both the form in which the said solvent contains an organic solvent, and the form in which the said solvent contains water are suitable forms of this invention. Especially, in order to control the hydration of the said inorganic particle, it is preferable that the said solvent contains an organic solvent.
In addition, when the said solvent contains water and an organic solvent, it is suitable that water is 50 mass% or less with respect to 100 mass% of the total amount of the organic solvent and water in the said solvent. Thereby, it becomes possible to control the hydration of the hydraulic inorganic particles. More preferably, it is 30 mass% or less, More preferably, it is 10 mass% or less, Especially preferably, it is 5 mass% or less, More preferably, it is 1 mass% or less, Most preferably, it is as a ratio of the water with respect to 100 mass% of the total amount of an organic solvent and water. It is most preferable that water is not substantially included, that is, when an organic solvent is used, water is not substantially included.

Examples of the organic solvent include alcohols such as methanol, ethanol, isopropanol, n-butanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, and glycerin; ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether. Ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and 3-methoxybutyl acetate; aromatic hydrocarbons such as toluene, xylene and ethylbenzene Use one or more of chloroform, amides such as dimethylformaldehyde, etc. It can be. Preferably, alcohols, ethers, ketones, and esters are used, and alcohols or mixed solvents of alcohols and other organic solvents are more preferable.

In the dispersion step, it is preferable that the amount of the solvent includes an organic dispersant and is an amount capable of dispersing the inorganic particles. Specifically, it is preferable to use 5 to 2000 parts by weight of the solvent with respect to 100 parts by weight of the inorganic particles to be surface-coated. More preferably 10 parts by weight or more, still more preferably 14 parts by weight or more, more preferably 300 parts by weight or less, still more preferably 200 parts by weight or less, particularly preferably 100 parts by weight or less, and most preferably 50 parts by weight. It is as follows. If the amount of the solvent is small, the inorganic particles cannot be sufficiently dispersed and the inorganic particles cannot be prevented from agglomerating, so that the kneading time cannot be shortened. If the amount of the solvent is too large, a large amount of energy and time are required for distilling off the solvent, which is not economical.
The amount of the solvent is preferably 500 to 100,000 parts by weight with respect to 100 parts by weight of the organic dispersant in the surface-coated inorganic particles. More preferably 1000 parts by weight or more, further preferably 1400 parts by weight or more, particularly preferably 2000 parts by weight or more, most preferably 2300 parts by weight or more, more preferably 50000 parts by weight or less, still more preferably 30000 parts by weight. The amount is particularly preferably 20000 parts by weight or less.

The amount of the organic dispersant used may be appropriately determined in consideration of the physical properties of the inorganic particles, the dispersibility of the resulting surface-coated inorganic particles, and the like. It is preferable that the content be 0.01 to 10 parts by weight. Within this range, the inorganic particles can be more fully and efficiently coated, and the dispersibility of the resulting surface-coated inorganic particles is more fully exhibited. More preferably, it is 0.01-5 weight part, More preferably, it is 0.05-4 weight part, More preferably, it is 0.05-3 weight part.

In the said manufacturing method, after the said dispersion | distribution process, a solvent is distilled off and pulverization is performed (it is also called a pulverization process). The means for distilling off the solvent is not particularly limited. For example, the solvent may be volatilized by heating or drying, and it is also suitable to distill off the solvent under reduced pressure. The powdering means is not particularly limited, and pulverization may be performed using a raw material pulverizer or the like.
In addition, it is suitable to adjust the particle diameter of the surface-coated inorganic particles obtained using a sieve (for example, a JIS test sieve) after the powdering step.

(Surface coating agent)
The present invention also provides a surface coating agent for inorganic particles used to obtain the surface-coated inorganic particles, wherein the inorganic particles are at least one selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles. It is a seed and the surface coating agent is also a surface coating agent containing a polycarboxylic acid-based polymer containing polyalkylene glycol.
As described above, the polycarboxylic acid-based polymer containing polyalkylene glycol has high adsorptivity to the surface of hydraulic inorganic particles and pozzolanic active inorganic particles, and can impart high dispersibility after surface coating. Particularly suitable as a surface coating agent for obtaining the above surface-coated inorganic particles.

The polycarboxylic acid-based polymer containing the polyalkylene glycol is as described above, and in particular, the structure derived from the unsaturated polyalkylene glycol ether monomer (a) represented by the general formula (1). A polymer having a unit and a structural unit derived from the unsaturated carboxylic acid monomer (b) is preferred. Thus, the use of the polycarboxylic acid-based polymer containing the polyalkylene glycol as a surface coating agent for at least one inorganic particle selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles, This is one of the preferred forms of the present invention. Moreover, q in the general formula (1) is preferably 0.

The surface coating agent also has an effect of assisting the pulverization of the inorganic particles as well as the surface coating effect of the inorganic particles. Therefore, it is also suitable to use the above-mentioned surface coating agent as a grinding aid in the grinding process during the production of inorganic particles. However, in order to achieve the present invention, it is necessary for the particles to be dispersed during the pulverization of the inorganic particles, and it is preferable to pulverize in a form containing the above-mentioned certain amount of solvent.

(Hydraulic composition)
The surface-coated inorganic particles of the present invention can be mixed with water to give a hydraulic composition. Such a hydraulic composition containing the above surface-coated inorganic particles and water is one of the preferred embodiments of the present invention. Examples of the hydraulic composition include cement paste, mortar, concrete, plaster and the like.

The hydraulic composition may contain aggregates such as fine aggregate (sand, etc.) and coarse aggregate (crushed stone, etc.) as necessary. Specifically, for example, gravel, crushed stone, granulated slag, recycled aggregate, etc., siliceous, clay, zircon, high alumina, silicon carbide, graphite, chrome, chromic, magnesia Fireproof aggregates such as can also be used.

The hydraulic composition may also contain a dispersant as required. Since the surface-coated inorganic particles of the present invention are partially or wholly coated with an organic dispersant, the hydraulic composition including the surface-coated inorganic particles has sufficient fluidity even without a separate dispersant. Although it can be shown, if necessary, a dispersant may be further contained. As the dispersant, one or more commonly used ones can be used. Specific examples are as described above.

The hydraulic composition may further include hydraulic inorganic particles and / or pozzolanic active inorganic particles that are not coated on the surface, in addition to the surface-coated inorganic particles, if necessary. In this case, the surface-coated inorganic particles are preferably 2% by mass or more, more preferably 5% by mass with respect to the total amount of inorganic particles of 100% by mass, in order to more fully express the effect of the surface-coated inorganic particles. % Or more. More preferably, it is 10 mass% or more, More preferably, it is 30 mass% or more, Especially preferably, it is 50 mass% or more, More preferably, it is 80 mass% or more, Most preferably, it is 100 mass%.

In the hydraulic composition, the unit water amount per 1 m ^3, the total amount of hydraulic particles (referred to as B) (the amount used B), and the water / B ratio (mass ratio) are unit water amount = 100 to 185 kg / m ^3, use B amount = 250~800kg / ^{m 3,} it is preferable that the water / B ratio = 0.1 to 0.7. More preferably, the unit water amount is 120 to 175 kg / m ³ , the used B amount is 270 to 800 kg / m ³ , and the water / B ratio is 0.1 to 0.65, and can be used widely from poor blends to rich blends. However, it is also very effective for high-strength concrete having a unit water amount of 500 kg / m ³ or more and ultrahigh-strength concrete having 900 kg / m ³ or more. Further, in the present invention, a hydraulic composition having a low water / B ratio has an effect that the kneading time is fast and excellent fluidity can be exhibited. It can be confirmed more sufficiently when the / B ratio is 0.5 or less. The water / B ratio is more preferably 0.4 or less, still more preferably 0.35 or less, still more preferably 0.3 or less, particularly preferably 0.25 or less, and most preferably 0.2 or less.

The hydraulic composition is also effective, for example, for ready-mixed concrete, concrete for secondary concrete products (precast concrete), centrifugal molded concrete, vibration compacted concrete, steam-cured concrete, shotcrete, etc. High fluidity of medium fluidity concrete (concrete with slump value of 22-25cm), high fluidity concrete (concrete with slump value of 25cm or more, slump flow value of 50-70cm), self-filling concrete, self-leveling material, etc. It is also effective for required mortar and concrete.

The hydraulic composition may further include one or more of those usually used as a cement additive (material). For example, water-soluble polymer materials exemplified in International Publication No. 2014/010572 [0066] to [0072]; polymer emulsion; retarder; early strengthening agent / accelerator; mineral oil-based antifoaming agent; Foaming agent; fatty acid-based antifoaming agent; fatty acid ester-based antifoaming agent; oxyalkylene-based antifoaming agent; alcohol-based antifoaming agent; amide-based antifoaming agent; phosphate ester-based antifoaming agent; Silicone antifoaming agent; AE agent; other surfactants; waterproofing agent; rust preventive agent; cracking reducing agent; expansion material; cement wetting agent; thickening agent; separation reducing agent; Agents, self-leveling agents, rust preventives, coloring agents, fungicides, and the like.

[Method for producing hydraulic composition]
A method for producing a hydraulic composition using the surface-coated inorganic particles is also one aspect of the present invention. As such a production method, for example, it is preferable to include a step of mixing the surface-coated inorganic particles, water, and other components added as necessary, and the other steps are particularly It is not limited. In the present invention, by using the above surface-coated inorganic particles, a hydraulic composition exhibiting high fluidity can be easily obtained in a short time. Therefore, the method for producing such a hydraulic composition includes a hydraulic composition. This is extremely useful in the technical field where products are used.

Since the surface-coated inorganic particles of the present invention are configured as described above, the kneading time can be remarkably shortened, and the productivity of the hydraulic composition can be greatly improved. Moreover, since the hydraulic composition using such surface-coated inorganic particles is extremely excellent in fluidity, it greatly contributes to the civil engineering / construction field and the like that handle concrete. Furthermore, the surface coating agent containing a polycarboxylic acid-based polymer containing polyalkylene glycol is adsorbed and adhered to hydraulic inorganic particles and pozzolanic active inorganic particles, and after adsorption and adhesion (that is, after surface coating). Since it is extremely excellent in particle dispersibility, it is particularly suitable for use as a surface coating agent for hydraulic inorganic particles or pozzolanic active inorganic particles.

A graph created by plotting the relative surface concentration of C _1s against Si _2p and Ca _2p against the depth from the particle surface for the inorganic particles used in each of Test Examples 1-1, 2-1 and 3-1. It is. In Test Example 1-1, the time when the cement and water were added was set to 0 seconds (s), and the state of the hydraulic composition until stirring was stopped was photographed every 20 to 60 seconds (s). In Test Example 2-1, the time when the cement and water were added was set to 0 second (s), and the state of the hydraulic composition until the stirring was stopped was photographed over time.

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. In addition, the weight average molecular weight of the polymer obtained in the preparation example was measured by the GPC measurement method described above. Moreover, the particle size of the particles and the relative surface concentration of C _1s with respect to the surface Si _2p and Ca _2p were measured by the methods described above.
The flow value of the cement paste obtained in the test example was measured as follows.
<Measurement of flow value>
The prepared paste was packed in a hollow cylindrical container having a diameter of 55 mm and a height of 50 mm placed on a horizontal table, and then the hollow cylindrical container was lifted vertically, and the diameter of the paste spread on the table was adjusted to 2 The direction was measured, and this average value was taken as the flow value.

Preparation Example 1 (Preparation of polycarboxylic acid dispersant (1))
In a glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introducing tube and a reflux condenser, 209.0 g of ion-exchanged water and 3-methyl-3-buten-1-ol were averaged with ethylene oxide (EO). Then, 444.8 g of an unsaturated polyalkylene glycol ether (MBO-50) added in an amount of 50 mol was charged, the reaction apparatus was purged with nitrogen under stirring, and the temperature was raised to 58 ° C. Next, an aqueous solution obtained by diluting 85.2 g of acrylic acid with 154.3 g of ion-exchanged water was dropped over 5 hours. At the same time, an aqueous solution in which 0.94 g of L-ascorbic acid and 8.0 g of 3-mercaptopropionic acid were dissolved in 48.9 g of ion-exchanged water, and an aqueous solution in which 4.9 g of ammonium persulfate was dissolved in 44.0 g of ion-exchanged water. It was dripped over 5 hours. After completion of dropping, stirring was continued at 58 ° C. for 1 hour to complete the polymerization reaction, and an aqueous solution of a polycarboxylic acid copolymer having a weight average molecular weight (Mw) of 9200 was obtained. The obtained polycarboxylic acid copolymer was dried at 50 ° C. under reduced pressure (50 mmHg), pulverized, and prepared into a powdery polycarboxylic acid copolymer that passed 70 mesh in the JIS test sieve mesh conversion table. did. This is referred to as a polycarboxylic acid dispersant (1).

Preparation Example 2 (Preparation of polycarboxylic acid dispersant (2))
A glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introduction tube and a reflux condenser was charged with 350 g of ion-exchanged water, and the reactor was purged with nitrogen under stirring, and the temperature was raised to 80 ° C. Next, an aqueous solution prepared by dissolving 315.2 g of methoxypolyethylene glycol methacrylate (addition mole number of ethylene oxide: 23 mol), 83.7 g of methacrylic acid, and 8.5 g of 3-mercaptopropionic acid with 171.4 g of ion-exchanged water for 3 hours. It was dripped over. At the same time, an aqueous solution in which 6.6 g of sodium persulfate was dissolved in 63.5 g of ion-exchanged water was dropped over 4 hours. After completion of the dropping, stirring was continued at 80 ° C. for 1 hour to complete the polymerization reaction, and an aqueous solution of a polycarboxylic acid copolymer having a weight average molecular weight (Mw) of 9500 was obtained. The obtained polycarboxylic acid copolymer was dried at 50 ° C. under reduced pressure (50 mmHg), pulverized, and prepared into a powdery polycarboxylic acid copolymer that passed 70 mesh in the JIS test sieve mesh conversion table. did. This is referred to as a polycarboxylic acid dispersant (2).

Production Example 1 (Production of surface-coated inorganic particles (1))
Ethanol in which 700 g of silica fume cement manufactured by Mitsubishi Ube Co., Ltd. was charged into a Hobart mixer, and 4.2 g (0.6% by mass with respect to the solid content of cement) of the polycarboxylic acid-based dispersant (1) obtained in Preparation Example 1 was dissolved. 102.2 g of the solution (98 g of ethanol, ethanol / cement mass ratio = 0.14) was charged into the mixer. After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. 180 seconds after the addition of the ethanol solution, the speed was switched to the second speed, stirring was resumed, stirring was stopped for 180 seconds, and stirring was stopped. The obtained paste was transferred to a vat and dried under reduced pressure (50 mmHg) at 50 ° C. to completely remove ethanol. Silica fume cement (surface-coated inorganic particles) whose surface is coated with a polycarboxylic acid dispersant (1) after drying, pulverizing, adjusting the particle size using a sieve corresponding to 70 mesh in the JIS test sieve mesh conversion table (Also referred to as (1)).

Test Example 1-1
600 g of the silica fume cement (surface-coated inorganic particles (1)) obtained in Production Example 1 was charged into a Hobart mixer, and 84 g of water was charged into the mixer (water / cement mass ratio = 0.14). After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. After 180 seconds from the addition of water, stirring was resumed at the second speed, and stirring was continued for 180 seconds. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 2. Moreover, the photograph which image | photographed the state at the time of stirring over time is shown in FIG. The results of measuring the flow value of the obtained paste are shown in Table 2.
For the surface-coated silica fume cement (surface-coated inorganic particles (1)) used in Test Example 1-1, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface was measured by XPS. The results are shown in Table 1 and FIG.

Test Example 2-1
84 g of water in which 600 g of silica fume cement manufactured by Mitsubishi Ube Co., Ltd. was charged into a Hobart mixer and 3.6 g of the polycarboxylic acid dispersant (1) obtained in Preparation Example 1 was dissolved (addition amount of polycarboxylic acid dispersant = cement) 0.6% by mass with respect to the solid content) was charged into the mixer (water / cement mass ratio = 0.14). After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. After 180 seconds from the addition of water, stirring was resumed at the second speed, and stirring was continued for 180 seconds. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 2. Moreover, the photograph which image | photographed the state at the time of stirring with time is shown in FIG. The results of measuring the flow value of the obtained paste are shown in Table 2.
In addition, about the silica fume cement made from Ube Mitsubishi Corp. which is not performing the surface coating used for Test Example 2-1, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface was measured by XPS. The results are shown in Table 1 and FIG.

Test Example 3-1
Premix cement containing 4.2 g of the powdered polycarboxylic acid-based dispersant (1) obtained in Preparation Example 1 and 700 g of silica fume cement manufactured by Ube Mitsubishi Corp. and containing the powdered polycarboxylic acid-based dispersant (1) Got.
600 g of this premix cement was put into a Hobart mixer, and 84 g of water was put into the mixer (water / cement mass ratio = 0.14). After the addition, a cement paste was produced in the same manner as in Test Example 1-1. However, stirring was resumed at the second speed 180 seconds after the addition of water, and then stirring was continued for 240 seconds. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 2. In addition, Table 2 shows the result of measuring the flow value of the obtained paste.
In addition, about the premix cement used for Test Example 3-1, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface was measured by XPS. The results are shown in Table 1 and FIG.

In each of the above test examples, the water / cement mass ratio (W / C) was 0.14 (14%), which was very low. In addition, it is W / C = 0.45-0.6 (45-60%) in general concrete, and W / C = 0.3 (30%) also in high-strength concrete.
Test Example 2-1 is an example using ordinary cement, and the cement has a relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the cement particle surface (depth 0 nm) (“C / (Si + Ca) ”) is 0.32, and the relative surface concentration of C _1s having an average depth of ₁ to 2 nm from the particle surface is 0.11. In this case, it took about 300 seconds (5 minutes) until the cement paste exhibited a certain fluidity (that is, until the fluidity was stabilized). On the other hand, in Test Example 1-1 using the surface-coated inorganic particles of the present invention, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface (depth 0 nm) of the silica fume cement was 1.02. The relative surface concentration of C _1s with an average depth of ₁ to 2 nm from the surface is as high as 0.32. And despite the same W / C conditions as in Test Example 2-1, the time required to develop a certain fluidity was about 90 seconds, and it was found that significant shortening of the kneading time could be achieved. .
Since the organic dispersant used as the surface coating agent for cement particles in Test Example 1-1 is the same as the dispersant added to the cement in Test Example 2-1, It was found that the confirmed effect of shortening the kneading time was due to the difference in the carbon content ratio on the cement particle surface.

Test Example 3-1 is an example using a premix cement obtained by mixing the same organic dispersant as used in Test Example 1-1 and Test Example 2-1 with cement particles as a powder. , the cement, _Si relative surface concentration of _{C 1s} for _2p and _{Ca 2p} 0.34 cement particle surface (depth 0 nm), the relative surface concentration of _{C 1s} of the average depth in 1~2nm from the particle surface of 0.12. In this case, the kneading time was longer than that in Test Example 2-1. Therefore, it was found that even when the organic dispersant was powdered, it did not contribute to shortening the kneading time, but rather the kneading time was prolonged.

1 and 2 show the following.
In Test Example 1-1, since the organic dispersant was coated with the inorganic particles, as shown in FIG. 2, the aggregation of the inorganic particles did not occur immediately after the addition of water. Since an aggregate of inorganic particles was not constructed, water quickly spread to the inorganic particles, and reached an equilibrium state between dispersion and aggregation in a short time (90 seconds). On the other hand, in Test Example 2-1, as shown in FIG. 3, immediately after adding water containing an organic dispersant, aggregation of inorganic particles occurs instantaneously, and water containing a dispersant is contained in the aggregate. Was constrained to become lumpy (0 to 90 seconds), and it took 300 seconds for dispersion and aggregation to reach equilibrium.

Test Example 1-2
The surface-coated silica fume cement (surface-coated inorganic particles (1)) obtained in Production Example 1 was weighed to the fourth decimal place (about 5 g) using a precision balance in the crucible. A crucible containing a weighed silica fume cement was placed in an electric furnace (AD-VANTEC KM-600) and heated at 450 ° C. in an air atmosphere (flow rate 2 L / min) for 3 hours. After 3 hours, take out the crucible from the electric furnace, let it cool to room temperature in a desiccator, weigh the silica fume cement with a precision balance to the fourth decimal place, and heat it from the ratio of the charged amount and the remaining amount. The residual rate (q) of was measured. Subsequently, the same crucible was put into the electric furnace again and heated at 550 ° C. in a nitrogen atmosphere (flow rate 2 L / min) for 3 hours. After 3 hours, the mixture was allowed to cool in a desiccator, and the residual rate (r) after heating at 550 ° C. was measured.
From the difference between the residual rate (q) at 450 ° C. and the residual rate (r) at 550 ° C., the hydration degree (= q−r) of chemically bonded water in the silica fume cement was calculated. The results are shown in Table 3.

Test Example 2-2
The degree of hydration was measured in the same manner as in Test Example 1-2 for the silica fume cement manufactured by Ube-Mitsubishi Corporation that was not subjected to the surface coating used in Test Example 2-1. The results are shown in Table 3.

Test Example 3-2
The degree of hydration was measured in the same manner as in Test Example 1-2 for the premix cement containing the powdered polycarboxylic acid dispersant (1) used in Test Example 3-1. The results are shown in Table 3.

In Test Example 1-2 and Test Example 2-2, it was found that the change in the weight of the cement from 450 ° C. to 550 ° C. was small, and the amount of chemically bonded water in the cement was small. In Test Example 3-2, the powdered polycarboxylic acid-based dispersant (1) was not sufficiently thermally decomposed at 450 ° C., so that the weight change of the cement from 450 ° C. to 550 ° C. was estimated to be large. Even from the weight change after heating, the surface-coated cement (that is, the surface-coated inorganic particles (1) obtained in Production Example 1), the surface-coated cement (that is, commercially available silica fume cement), and the powdered polycarboxylic acid It was found that the properties were different from those of the premix cement containing the acid dispersant (that is, the premix cement containing the powdered polycarboxylic acid dispersant (1)).

In addition, about the surface coating inorganic particle (1) obtained by manufacture example 1, it is the carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersing agent similarly to test example 4-2 mentioned later. ) Relative surface concentration (z), the relative surface concentration of carbon (C) relative to silicon (Si) and calcium (Ca) per unit amount of organic dispersant on the particle surface is 0.84, The relative surface concentration of carbon (C) having an average depth of 1 to 2 nm from the particle surface was 0.24.

Production Example 2 (Production of surface-coated inorganic particles (2))
Ethanol in which 700 g of silica fume cement manufactured by Mitsubishi Ube Co., Ltd. was charged into a Hobart mixer, and 4.2 g (0.6% by mass with respect to the solid content of cement) of the polycarboxylic acid-based dispersant (2) obtained in Preparation Example 2 was dissolved. 102.2 g of the solution (98 g of ethanol, ethanol / cement mass ratio = 0.14) was charged into the mixer. After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. 180 seconds after the addition of the ethanol solution, the speed was switched to the second speed, stirring was resumed, stirring was stopped for 180 seconds, and stirring was stopped. The obtained paste was transferred to a vat and dried under reduced pressure (50 mmHg) at 50 ° C. to completely remove ethanol. Silica fume cement (surface-coated inorganic particles) whose surface is coated with a polycarboxylic acid dispersant (2) after drying, pulverizing, adjusting the particle size using a sieve corresponding to 70 mesh in the JIS test sieve mesh conversion table (Also referred to as (2)).

Production Example 3 (Production of surface-coated inorganic particles (3))
Ethanol in which 700 g of Ube-Mitsubishi silica fume cement was charged into a Hobart mixer and 2.8 g of polycarboxylic acid dispersant (2) obtained in Preparation Example 2 was dissolved (0.4% by mass with respect to the solid content of cement) was dissolved. 100.8 g of solution (98 g of ethanol, ethanol / cement mass ratio = 0.14) was put into the mixer. After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. 180 seconds after the addition of the ethanol solution, the speed was switched to the second speed, stirring was resumed, stirring was stopped for 180 seconds, and stirring was stopped. The obtained paste was transferred to a vat and dried under reduced pressure (50 mmHg) at 50 ° C. to completely remove ethanol. Silica fume cement (surface-coated inorganic particles) whose surface is coated with a polycarboxylic acid dispersant (2) after drying, pulverizing, adjusting the particle size using a sieve corresponding to 70 mesh in the JIS test sieve mesh conversion table (3) is also obtained.

Production Example 4 (Production of surface-coated inorganic particles (4))
700 g of silica fume cement manufactured by Ube-Mitsubishi Co., Ltd. was put into a Hobart mixer and stirred at the first speed for 240 seconds. Simultaneously with stirring, 21 g of an aqueous solution in which 4.2 g (0.6% by mass based on the solid content of cement) of the polycarboxylic acid dispersant (2) obtained in Preparation Example 2 was dissolved (16.8 g of water, water / The cement mass ratio = 0.024) was sprayed onto the cement in the mixer over 240 seconds to uniformly coat the polycarboxylic acid dispersant (2) on the cement particles. Stirring was stopped, and the resulting powder was transferred to a vat and dried under reduced pressure (50 mmHg) at 50 ° C. to completely evaporate water that can be evaporated (partially remains as bound water). After drying, the particle size is adjusted using a sieve corresponding to 70 mesh in the JIS test sieve mesh conversion table, and the silica fume cement (surface-coated inorganic particles (4) is coated with the polycarboxylic acid dispersant (2). Obtained).

Test Example 4-1
600 g of the silica fume cement (surface-coated inorganic particles (2)) obtained in Production Example 2 was charged into a Hobart mixer, and 84 g of water was charged into the mixer (water / cement mass ratio = 0.14). After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. After 180 seconds from the addition of water, stirring was resumed at the second speed, and stirring was continued for 180 seconds. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 5. Table 5 shows the results of measuring the flow value of the obtained paste.
In addition, regarding the surface-coated silica fume cement (surface-coated inorganic particles (2)) used in Test Example 4-1, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface was measured by XPS. The results are shown in Table 4.

Test Example 5-1
600 g of the silica fume cement (surface-coated inorganic particles (3)) obtained in Production Example 3 was put into a Hobart mixer, and 84 g of water containing 0.6 g of the polycarboxylic acid-based dispersant (2) obtained in Preparation Example 2 (polycarboxylic acid). The amount of the acid dispersant added = 0.1% by mass with respect to the solid content of the cement) was charged into the mixer (water / cement mass ratio = 0.14). After the addition, a cement paste was prepared in the same manner as in Test Example 4-1. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 5. Table 5 shows the results of measuring the flow value of the obtained paste.

Test Example 6-1
84 g of water in which 600 g of silica fume cement manufactured by Mitsubishi Ube Co., Ltd. was charged into a Hobart mixer and 3.6 g of the polycarboxylic acid dispersant (2) obtained in Preparation Example 2 was dissolved (addition amount of polycarboxylic acid dispersant = cement) 0.6% by mass with respect to the solid content) was charged into the mixer (water / cement mass ratio = 0.14). After the addition, a cement paste was prepared in the same manner as in Test Example 4-1. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 5. Table 5 shows the results of measuring the flow value of the obtained paste.
In addition, about the silica fume cement made from Ube Mitsubishi Corp. which is not performing the surface coating used for Test Example 6-1, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface was measured by XPS. The results are shown in Table 4.

Test Example 7-1
600 g of the silica fume cement (surface-coated inorganic particles (4)) obtained in Production Example 4 was charged into a Hobart mixer, and 84 g of water was charged into the mixer (water / cement mass ratio = 0.14). After the addition, a cement paste was prepared in the same manner as in Test Example 4-1. Even after the completion of stirring, the softness of the paste did not become visually constant. Therefore, the “kneading time” was set to 480 seconds or more and listed in Table 5. Table 5 shows the results of measuring the flow value of the obtained paste.
Incidentally measurement, the silica fume cement subjected to surface coating by aqueous solution used in Test Example 7-1 (surface-coated inorganic particles (4)), the relative surface concentration of _{C 1s} for _{Si 2p} and _{Ca 2p} of the particle surface by XPS did. The results are shown in Table 4.

Test Example 4-2
The surface-coated silica fume cement (surface-coated inorganic particles (2)) obtained in Production Example 2 was weighed to the fourth decimal place (about 5 g) using a precision balance in the crucible. A crucible containing a weighed silica fume cement was placed in an electric furnace (KM-600 manufactured by ADVANTEC), and heated at 150 ° C. in a nitrogen atmosphere (flow rate 2 L / min) for 3 hours. After 3 hours, take out the crucible from the electric furnace, let it cool to room temperature in a desiccator, weigh the silica fume cement with a precision balance to the fourth decimal place, and heat it from the ratio of the charged amount and the remaining amount. The residual ratio (p) of was measured. Subsequently, the same crucible was put into the electric furnace again and heated at 450 ° C. in an air atmosphere (flow rate 2 L / min) for 3 hours. After 3 hours, the mixture was allowed to cool in a desiccator, and the residual rate (q) after heating at 450 ° C. was measured. From the difference between the residual rate (p) at 150 ° C. and the residual rate (q) at 450 ° C., the content (= p−q) of the organic dispersant in the silica fume cement was calculated.
Subsequently, the same crucible was put into the electric furnace again and heated at 550 ° C. in a nitrogen atmosphere (flow rate 2 L / min) for 3 hours. After 3 hours, the mixture was allowed to cool in a desiccator, and the residual rate (r) after heating at 550 ° C. was measured. From the difference between the residual rate (q) at 450 ° C. and the residual rate (r) at 550 ° C., the hydration degree (= q−r) of chemically bonded water in the silica fume cement was calculated. The results are shown in Table 6.
About the silica fume cement obtained after heating at 550 _degreeC , the relative surface concentration of _{C1s with} respect to _Si2p and _Ca2p of the particle | grain surface was measured by XPS. The results are shown in Table 7.
From the results obtained in Tables 6 and 7, the relative surface concentration (z) of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant was calculated. The results are shown in Table 8.

Test Example 6-2
About the silica fume cement made from Ube Mitsubishi Corp. which has not been subjected to the surface coating used in Test Example 6-1, the ignition loss was measured in the same manner as in Test Example 4-2, and the content and hydration degree of the organic dispersant were measured. did. The results are shown in Table 6. About the silica fume cement obtained after heating at 550 _degreeC , the relative surface concentration of _{C1s with} respect to _Si2p and _Ca2p of the particle | grain surface was measured by XPS. The results are shown in Table 7.
From the results obtained in Tables 6 and 7, the relative surface concentration (z) of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant was calculated. The results are shown in Table 8.

Test Example 7-2
For the surface-coated silica fume cement (surface-coated inorganic particles (4)) obtained in Production Example 4 used in Test Example 7-1, the ignition loss was measured in the same manner as in Test Example 4-2, and the organic dispersant was measured. Content and degree of hydration were measured. The results are shown in Table 6. About the silica fume cement obtained after heating at 550 _degreeC , the relative surface concentration of _{C1s with} respect to _Si2p and _Ca2p of the particle | grain surface was measured by XPS. The results are shown in Table 7.
From the results obtained in Tables 6 and 7, the relative surface concentration (z) of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant was calculated. The results are shown in Table 8.

From Tables 4 to 8, the following was found.
Test Example 6-1 is an example using the same normal silica fume cement as Test Example 2-1, and an aqueous solution containing the polycarboxylic acid dispersant (2) obtained in Preparation Example 2 was added and kneaded. It took about 285 seconds for the cement paste to exhibit a certain fluidity (Table 5).
On the other hand, in Test Example 4-1 using the surface-coated inorganic particles (2) of the present invention, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface (depth 0 nm) of the silica fume cement was 1. 18. The relative surface concentration of C _1s having an average depth of ₁ to 2 nm from the particle surface was as high as 0.32, and the flow was constant despite the same W / C conditions as in Test Example 6-1. The time required to develop the property was about 165 seconds, and it was found that the kneading time was significantly shortened (Table 5).
Since the organic dispersant used as the cement particle surface coating agent in Test Example 4-1 is the same as the dispersant added to the cement in Test Example 6-1, It was found that the confirmed effect of shortening the kneading time was due to the difference in the carbon content ratio on the cement particle surface.

In Test Example 5-1, a small amount of the polycarboxylic acid-based dispersant was added to the silica fume cement (surface-coated inorganic particles (3)) that was surface-coated with the small amount of the polycarboxylic acid-based dispersant obtained in Production Example 3. By adding and kneading the aqueous solution to be contained, fluidity and kneading time equal to or higher than that of Test Example 4-1 were achieved even though the total amount of polycarboxylic acid-based dispersant used was smaller. Okay (Table 5).

Test Example 7-1 is an example using the cement (surface-coated inorganic particles (4)) obtained in Production Example 4, that is, the surface-coated cement obtained by spraying an aqueous solution containing a dispersant onto the cement. In this case, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface (depth 0 nm) of the silica fume cement is 0.73, and the average surface concentration of C _1s with an average depth of ₁ to 2 nm from the particle surface is Although it was 0.28, which was the same amount of dispersant as in Test Example 4-1, the value was smaller than that in Test Example 4-1. Then, it took about 480 seconds or more to develop a certain fluidity, and the flow value was as small as 55 mm (Table 5).
When surface-coated inorganic particles (4) were used in the same manner as in Test Example 7-1, the particle surface of silica fume cement per unit amount of organic dispersant (depth 0 nm) from Test Example 7-2 in Table 8 The relative surface concentration of C _1s with respect to Si _2p and Ca _2p of 0.53, the relative surface concentration of C _1s having an average depth of ₁ to 2 nm from the particle surface is 0.19, and the surface-coated inorganic particles of the present invention ( The value was lower than the value of Test Example 4-2 using 2) (Table 8).
From these results, in the method of spraying a small amount of aqueous solution as in the surface-coated inorganic particles (4), since the dispersant is not sufficiently coated on the cement surface, the aggregation of the cement particles can be prevented. Therefore, it is considered that the shortening of the kneading time was not recognized.

In Test Example 4-2 and Test Example 6-2, it was found that the change in the weight of the cement from 450 ° C. to 550 ° C. was small, and the amount of chemically bonded water in the cement was small (Table 6). In Test Example 7-2, the rate of change from 450 ° C. to 550 ° C. is large (Table 6). This is because the cement-bound water was generated because the aqueous solution was sprayed. In Test Example 7-2, it is presumed that the fluidity was not improved because the dispersant was taken into the hydrate. Therefore, it was found that it is preferable to use an organic solvent in order to reduce the degree of hydration.
Further, it has been found that the method of spraying with an aqueous solution as in Patent Document 2 cannot achieve improvement in fluidity and reduction in kneading time.

Although not shown in the table, for the surface-coated inorganic particles (3) obtained in Production Example 3, in the same manner as in Test Example 4-2, silicon (Si) and calcium per unit amount of organic dispersant ( The relative surface concentration (z) of carbon (C) with respect to Ca) was determined, and the relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant on the particle surface was 0.00. The relative surface concentration of carbon (C) having an average depth of 1 to 2 nm from the particle surface is confirmed to be 0.2 to 5. In addition, the degree of hydration of the surface-coated inorganic particles (3) obtained in Production Example 3 was also confirmed to be 0.1 or less.

Production Example 5 (Production of surface-coated inorganic particles)
100 g of silica fume (940-U) manufactured by Elchem, Inc. was charged into a Hobart mixer, and 214 g (water) of 14 g (14% by mass with respect to silica fume) of the polycarboxylic acid dispersant (1) obtained in Preparation Example 1 was dissolved. 200 g, water / silica fume mass ratio = 2.0) was charged into the mixer. After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped. The resulting silica fume slurry was transferred to a vat and dried under reduced pressure (50 mmHg) at 50 ° C. to completely distill off water. After drying, pulverization was performed, the particle size was adjusted using a sieve corresponding to 93 mesh in the JIS test sieve mesh conversion table, and silica fume whose surface was coated with the polycarboxylic acid dispersant (1) was obtained. About the obtained silica fume, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface was measured by XPS. The results are shown in Table 9.
Next, 35 g of the obtained silica fume and 665 g of commercially available Pacific ordinary Portland cement were mixed (silica fume / silica fume mixed cement mass ratio = 0.05) to prepare a silica fume mixed cement. The obtained silica fume mixed cement was also evaluated on the particle surface, and the particle size was measured. The results are shown in Table 9.

Test Example 8
600 g of the silica fume mixed cement obtained in Production Example 5 was charged into a Hobart mixer, and 96 g of water was charged into the mixer (water / cement mass ratio = 0.16). After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. After 180 seconds from the addition of water, stirring was resumed at the second speed, and stirring was continued for 240 seconds. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 10. Table 10 shows the result of measuring the flow value of the obtained paste.

Production Example 6
100 g of silica fume (940-U, particle size 0.1 μm) manufactured by Elchem Co. was put into a Hobart mixer, and 200 g of water was put into the mixer. After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped. The resulting silica fume slurry was transferred to a vat and dried under reduced pressure (50 mmHg) at 50 ° C. to completely distill off water. After drying, pulverization was performed, and the particle size was adjusted using a sieve corresponding to 93 mesh in the JIS test sieve mesh conversion table to obtain a silica fume for comparison. About the obtained silica fume, the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the particle surface was measured by XPS. The results are shown in Table 9.
Next, 35 g of the obtained silica fume and 665 g of commercially available Pacific ordinary Portland cement were mixed (silica fume / silica fume mixed cement mass ratio = 0.05) to prepare a comparative silica fume mixed cement. The obtained silica fume mixed cement was also evaluated on the particle surface and the particle size was measured. The results are shown in Table 9.

Test Example 9
600 g of the silica fume mixed cement obtained in Production Example 6 was put into a Hobart mixer, and 99.6 g of water containing the polycarboxylic acid dispersant (1) obtained in Preparation Example 1 (addition amount of polycarboxylic acid dispersant = cement) 0.6 mass% with respect to the solid content) was charged into the mixer (water / cement mass ratio = 0.16). After the addition, the mixture was stirred at the first speed for 120 seconds, and then the stirring was stopped, and the paste adhering to the container wall surface was scraped off over 30 seconds. After 180 seconds from the addition of water, stirring was resumed at the second speed and stirring was continued for another 15 minutes. The time until cement and water were added was set to 0 second, and the time until the softness of the paste became visually constant was described as “kneading time” in Table 10. Table 10 shows the result of measuring the flow value of the obtained paste.

In Test Example 9, it took about 17 minutes for the cement paste to exhibit a certain fluidity. On the other hand, in Test Example 8 using the surface-coated inorganic particles of the present invention, the time required to develop a certain fluidity is about 5 minutes despite the same W / C conditions as in Test Example 9. Thus, it was found that the kneading time was significantly shortened.

When comparing the relative surface concentration of C _1s with respect to Si _2p and Ca _2p on the silica fume particle surface (Table 9), the silica fume used in Test Example 8 (Production Example 5) and the silica fume used in Test Example 9 (Production Example 6) Thus, since a remarkable difference was confirmed, it can be said that the silica fume mixed cement obtained in Production Example 5 was confirmed to be one in which part or all of the particle surface was sufficiently coated with an organic dispersant. .

Although not shown in the table, for each of the silica fume and the silica fume mixed cement obtained in Production Example 5, in the same manner as in Test Example 4-2, silicon (Si) and calcium per unit amount of organic dispersant ( The relative surface concentration (z) of carbon (C) with respect to Ca) was determined, and both were the relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) per unit amount of organic dispersant on the particle surface. Is 0.6 to 10, and it is confirmed that the relative surface concentration of carbon (C) having an average depth of 1 to 2 nm from the particle surface is 0.2 to 5. Moreover, also about the hydration degree of the silica fume obtained by manufacture example 5, and the silica fume mixing cement, it has confirmed that all are 0.1 or less.

Claims (2)

A surface coating agent for inorganic particles used to obtain surface-coated inorganic particles,
The inorganic particles are at least one selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles,
The surface coating agent has the following general formula (1):
(In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group. P represents an integer of 0 to 2. q represents 0. AO is the same or different. Represents an oxyalkylene group having 2 to 18 carbon atoms, n is an average addition mole number of the oxyalkylene group represented by AO, and is a number of 2 to 300. R ³ is a hydrogen atom or a carbon number of 1 to 1; And a structural unit derived from an unsaturated polyalkylene glycol monomer (a) represented by (18) and a structural unit derived from an unsaturated carboxylic acid monomer (b). Including a carboxylic acid polymer,
The surface-coated inorganic particles are formed by coating part or all of the surface of at least one inorganic particle selected from the group consisting of hydraulic inorganic particles and pozzolanic active inorganic particles with an organic dispersant. When the relative surface concentration of carbon (C) with respect to silicon (Si) and calcium (Ca) is measured by XPS (however, PHI Quantera SXM manufactured by ULVAC-PKI is used as a measuring device), carbon (C). And a relative surface concentration of carbon (C) having an average depth of 1 to 2 nm from the particle surface is 0.15 to 50. . A composition comprising the surface coating agent according to claim 1 and an organic solvent.