JP4717642B2 - Concrete admixture - Google Patents

Description

  The present invention relates to a concrete admixture, preferably an admixture for concrete containing aggregates containing cement, blast furnace slag, fly ash, silica fume, etc., or lignite.

Concrete admixtures are materials used to modify the properties of concrete by reacting with or mixing with cement paste, and are often made of inorganic powders, which have a special function for cement substitutes and concrete. Used frequently to grant. Typical admixtures include blast furnace slag and artificial pozzolanes (fly ash, silica fume, etc.) for the purpose of cement replacement, and it is important in concrete production to add these appropriately. Generally, blast furnace slag, fly ash, silica fume and lignite contain black fine powder.

However, recent increases in the use of silica fume, fly ash, blast furnace slag, etc., incineration of ash into cement (use of industrial waste), use of aggregates and admixtures containing lignite, workability, Due to the high fluidity of concrete for the purpose of improving environmental properties, black spots appear on the skin surface after hardening of the concrete, or a phenomenon of blackening occurs overall. Especially, polycarboxylic acid polymers are used as water reducing agents. In the case of finished concrete, remarkable improvement measures are desired. As techniques for improving this, Patent Documents 1 and 2 disclose techniques using a copolymer of a chain olefin and an ethylenically unsaturated dicarboxylic acid. On the other hand, in Patent Document 3, a phosphate ester polymer is proposed as a cement dispersant.

JP 2004-83303 A JP 2004-175651 A JP 2000-327386 A

  However, in the conventional concrete admixture, the effect of preventing darkening of the concrete skin surface is not sufficient in the concrete blending system containing a large amount of the black fine particle component.

  An object of this invention is to provide the concrete admixture which can suppress the darkening which generate | occur | produces on a concrete skin surface even in the concrete compounding system with many black fine particle components contained.

  In the present invention, a monomer 1 represented by the general formula (1), a monomer 2 represented by the general formula (2), and a monomer 3 represented by the general formula (3) are copolymerized. The weight average molecular weight obtained by copolymerizing polymer A (hereinafter referred to as polymer A) and an olefin having 6 to 14 carbon atoms with maleic acid, maleic anhydride or maleate is 1,000 to 1,000. The present invention relates to a concrete admixture containing 20000 polymer B (hereinafter referred to as polymer B).

[In the formula, R ¹ and R ² are each a hydrogen atom or a methyl group, R ³ is a hydrogen atom, or — (CH ₂ ) _q (CO) _p O (AO) _r R ⁴ , and AO has 2 to 4 carbon atoms. An oxyalkylene group or an oxystyrene group, p is a number of 0 or 1, q is a number of 0 to 2, p and q are not simultaneously 0, r is an average added mole number of AO, a number of 3 to 300, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. ]

[Wherein R ¹¹ is a hydrogen atom or a methyl group, R ¹² is an alkylene group having 2 to 12 carbon atoms, m1 is a number of 1 to 30, M ³ and M ⁴ are a hydrogen atom, an alkali metal or an alkaline earth metal, respectively. Represents. ]

[Wherein R ¹³ and R ¹⁵ are each a hydrogen atom or a methyl group, R ¹⁴ and R ¹⁶ are each an alkylene group having 2 to 12 carbon atoms, m2 and m3 are each a number of 1 to 30 and M ⁵ is Represents a hydrogen atom, an alkali metal or an alkaline earth metal. ]

  The present invention also relates to a concrete admixture containing at least one selected from blast furnace slag, fly ash, stone powder, calcium carbonate, silica fume and lignite and the concrete admixture of the present invention.

  Further, the present invention is a hydraulic composition containing a hydraulic substance, one or more selected from blast furnace slag, fly ash, stone powder, calcium carbonate, silica fume and lignite, and the concrete admixture of the present invention, and The present invention also relates to a cured concrete body using the hydraulic composition.

  The present invention also relates to the monomer 1 represented by the general formula (1), the monomer 2 represented by the general formula (2), and the monomer 3 represented by the general formula (3). A polymer A obtained by copolymerization of olefin, and a polymer B having a weight average molecular weight of 1000 to 20000 obtained by copolymerization of an olefin having 6 to 14 carbon atoms and maleic acid, a hydraulic substance and water. The present invention relates to a method for preventing darkening of a concrete skin surface to be blended with a composition to be contained.

  ADVANTAGE OF THE INVENTION According to this invention, the concrete admixture which can suppress the darkening which generate | occur | produces on a concrete skin surface is provided even in the concrete compounding system with many black fine particle components contained. Therefore, the admixture of the present invention can suppress the occurrence of darkening on the surface of the concrete hardened body.

  A concrete admixture containing polymer A and polymer B can suppress darkening of the concrete surface even in a concrete compound system containing a large amount of fine black particles, which was not sufficient with conventional concrete admixtures. It is. Although this reason is unclear, it is considered to be due to a synergistic dispersion effect of the black fine particle components of the polymer A and the polymer B.

<Polymer A>
The polymer A is represented by the monomer 1 represented by the above general formula (1), the monomer 2 represented by the above general formula (2), and the above general formula (3). This is a phosphate ester polymer obtained by copolymerizing the monomer 3.

[Monomer 1]
In monomer 1, R ¹ and R ² in general formula (1) are each a hydrogen atom or a methyl group. R ³ is a hydrogen atom or — (CH ₂ ) _q (CO) _p O (AO) _r R ⁴ , preferably a hydrogen atom. Examples of the alkenyl of the general formula (1) include a vinyl group, an allyl group, and a methallyl group. When p is 0, AO forms an ether bond with (CH ₂ ) _q, and when p is 1, it forms an ester bond. q is 0 to 2, preferably 0 or 1, and more preferably 0. p and q are not 0 at the same time. AO is an oxyalkylene group having 2 to 4 carbon atoms or an oxystyrene group, and AO is preferably an oxyalkylene group having 2 to 4 carbon atoms, more preferably an ethyleneoxy group (hereinafter referred to as EO group), and an EO group. Is 70 mol% or more, more preferably 80 mol% or more, and further preferably 90 mol% or more. r is an average added mole number of AO, which is a number of 3 to 300, and is 3 to 300, preferably 4 to 120, from the viewpoint of dispersibility of the cement and darkening component with respect to the hydraulic composition of the polymer. More preferably 4 to 80, still more preferably 4 to 50, and particularly preferably 4 to 30. Moreover, AO is different in an average of r repeating units, and random addition, block addition, or a mixture thereof may be included. For example, AO can contain a propyleneoxy group etc. besides EO group.

R ⁴ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably 1 to 12, more preferably 1 to 4, and further preferably 1 or 2, and particularly preferably a methyl group.

  Monomer 1 includes a half-terminated alkyl-capped polyalkylene glycol such as methoxypolyethylene glycol, methoxypolypropylene glycol, methoxypolybutylene glycol, methoxypolystyrene glycol, ethoxypolyethylenepolypropyleneglycol, (meth) acrylic acid, maleic acid (half ) Esterified products, etherified products with (meth) allyl alcohol, and (meth) acrylic acid, maleic acid, and (meth) allyl alcohol adducts having 2 to 4 carbon atoms are preferably used. In addition, (meth) acrylic acid means acrylic acid and / or methacrylic acid, and (meth) allyl means allyl and / or methallyl (the same applies hereinafter).

  More preferred is an esterified product of alkoxy, particularly methoxypolyethylene glycol and (meth) acrylic acid. Specific examples include ω-methoxypolyoxyalkylene methacrylate and ω-methoxypolyoxyalkylene acrylate, and ω-methoxypolyoxyalkylene methacrylate is more preferable.

  Monomer 1 used for production of polymer A can be obtained, for example, by esterification of alkoxypolyalkylene glycol and (meth) acrylic acid. From the viewpoint of the required addition amount and viscosity reduction when the esterified product is used in the concrete admixture of the present invention, the unreacted (meth) acrylic acid is 5% by weight based on the monomer 1 in terms of acid type. The following is preferable, 3% by weight or less is more preferable, 1.5% by weight or less is further preferable, and 1% by weight or less is more preferable. Examples of a method for reducing the amount of (meth) acrylic acid remaining during the production of the monomer 1 include topping, steaming, and solvent extraction.

[Monomer 2]
In the monomer (2), R ¹¹ is a hydrogen atom or a methyl group, and R ¹² is an alkylene group having 2 to 12 carbon atoms. m1 is a number from 1 to 30, and M ³ and M ⁴ are each a hydrogen atom, an alkali metal, or an alkaline earth metal. 1-20 are preferable, as for m1 in General formula (2), 1-10 are more preferable, and 1-5 are especially preferable.

  Specifically, phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester, phosphoric acid mono-[(2-hydroxyethyl) acrylic acid] ester, polyalkylene glycol mono (meth) acrylate acid phosphoric acid Examples include esters. Among these, phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester is preferable from the viewpoint of ease of production and product quality stability. Further, alkali metal salts, alkaline earth metal salts, ammonium salts, alkylammonium salts and the like of these compounds may be used.

[Monomer 3]
In the monomer 3, in the general formula (3), R ¹³ and R ¹⁵ are each a hydrogen atom or a methyl group, and R ¹⁴ and R ¹⁶ are each an alkylene group having 2 to 12 carbon atoms. m2, m3 is a number of each 1 to 30, M ⁵ represents a hydrogen atom, an alkali metal or alkaline earth metal. M2 and m3 in the general formula (3) are each preferably 1 to 20, more preferably 1 to 10, and particularly preferably 1 to 5.

  Specific examples thereof include phosphoric acid di-[(2-hydroxyethyl) methacrylic acid] ester, phosphoric acid di-[(2-hydroxyethyl) acrylic acid] ester, and the like. Among these, di-[(2-hydroxyethyl) methacrylic acid] ester phosphate is preferable from the viewpoint of ease of production and quality stability of the product. Further, alkali metal salts, alkaline earth metal salts, ammonium salts, alkylammonium salts and the like of these compounds may be used.

  Monomers 2 and 3 can be used as a mixed monomer including monomer 2 and monomer 3. Further, as the monomer 2 and the monomer 3, a phosphate ester obtained by reacting the organic hydroxy compound represented by the general formula (4) with a phosphorylating agent may be used.

  The mixed monomer including the monomer 2 and the monomer 3 is obtained as a reaction product by reacting, for example, an organic hydroxy compound represented by the general formula (4) and a phosphorylating agent at a predetermined charge ratio. It can also be manufactured.

[Wherein, R ²⁰ represents a hydrogen atom or a methyl group, R ²¹ represents an alkylene group having 2 to 12 carbon atoms, and m4 represents a number of 1 to 30. ]

  1-20 are preferable, as for m4 in General formula (4), 1-10 are more preferable, and 1-5 are especially preferable.

  As a phosphate ester, for example, when producing a mixture of mono (2-hydroxyethyl) methacrylic acid phosphate and di-[(2-hydroxyethyl) methacrylic acid] phosphate, a known technique (for example, JP-A-57) -180618).

  As the mixed monomer including the monomer 2 and the monomer 3, a commercial product including a monoester and a diester can be used. For example, Phosmer M, Phosmer PE, Phosmer P (Unichemical) , JAMP514, JAMP514P, JMP100 (all Johoku Chemical), light ester P-1M, light acrylate P-1A (all Kyoeisha Chemical), MR200 (Daihachi Chemical), Kayamar (Nippon Kayaku), Ethyleneglycol methacrylate phosphate (Aldrich) Reagent).

  Monomers 2 and 3 are phosphoric acid esters of monomers having unsaturated bonds and hydroxyl groups, and the above-mentioned commercially available products and reaction products include monoester (monomer 2) and diester ( It has been confirmed that it contains compounds other than monomer 3). These other compounds are considered to be a mixture of polymerizable and non-polymerizable compounds, but in the present invention, such a mixture (mixed monomer) can be used as it is.

  Moreover, the phosphate ester (Y) obtained by making the organic hydroxy compound represented by the said General formula (4) and a phosphorylating agent react can be used as the monomers 2 and 3.

  1-20 are preferable, as for m4 in General formula (4), 1-10 are more preferable, and 1-5 are especially preferable.

  Phosphoric acid ester (Y) has an organic hydroxy compound and a phosphorylating agent in a ratio defined by the following formula (I) of 2.0 to 4.0, more preferably 2.5 to 3.5, particularly 2.8. What was obtained by making it react on the conditions of -3.2 is preferable.

In the present invention, in the formula (I), the phosphorylating agent is treated as P ₂ O ₅ .n (H ₂ O) for convenience.

  Examples of the phosphorylating agent include orthophosphoric acid, phosphorus pentoxide (anhydrous phosphoric acid), polyphosphoric acid, phosphorus oxychloride and the like, and orthophosphoric acid and phosphorus pentoxide are preferable. These may be used alone or in combination of two or more. The amount of the phosphorylating agent in the reaction of the organic hydroxy compound and the phosphorylating agent can be appropriately determined according to the target phosphate ester composition.

The phosphorylating agent includes phosphorous pentoxide (Z-1) and at least one (Z-2) selected from the group consisting of water, phosphoric acid and polyphosphoric acid (hereinafter referred to as phosphorylating agent (Z)). In this case as well, in the formula (I), phosphorylation containing phosphorus pentoxide (Z-1) and at least one selected from the group consisting of water, phosphoric acid and polyphosphoric acid (Z-2) The agent (Z) is treated as P ₂ O ₅ · n (H ₂ O) for convenience.

Further, the number of moles of the phosphorylating agent defined by the formula (I) means the amount of phosphorous agent introduced into the reaction system as a raw material, particularly the amount of P ₂ O ₅ units derived from the phosphorylating agent (Z) (mole). ). The number of moles of water indicates the amount (mole) of water (H ₂ O) derived from the phosphorylating agent (Z) introduced into the reaction system as a raw material. That is, the reaction system includes water when polyphosphoric acid is represented as (P ₂ O ₅ .xH ₂ O) and orthophosphoric acid is represented as [1/2 (P ₂ O ₅ .3H ₂ O)]. It will contain all the water present in it.

  Moreover, 20-100 degreeC is preferable and, as for the temperature at the time of adding a phosphorylating agent to an organic hydroxy compound, 40-90 degreeC is more preferable. The time required for adding the phosphorylating agent to the reaction system (the time from the start of addition to the end of addition) is preferably 0.1 hour to 20 hours, and more preferably 0.5 hour to 10 hours.

  The temperature of the reaction system after adding the phosphorylating agent is preferably 20 to 100 ° C, more preferably 40 to 90 ° C.

  After completion of the phosphorylation reaction, the produced phosphoric acid condensate (an organic compound or phosphoric acid having a pyrophosphoric acid bond) may be reduced by hydrolysis, or the polymer A may be produced without hydrolysis. It is suitable as the monomer.

  The polymer A according to the present invention is a phosphate ester polymer obtained by copolymerizing the monomer 1, the monomer 2, and the monomer 3. It is also preferable to use a mixed monomer containing monomer 2 and monomer 3. The polymer A is preferably obtained by copolymerizing the monomers 1 to 3 at a pH of 7 or less.

  Preferable monomers 1, 2 and 3 are as described above, and the above-mentioned commercially available products and reaction products can also be used.

  In the copolymerization of the monomers, the molar ratio between the monomer 1 and the monomers 2 and 3 is as follows: monomer 1 / (monomer 2 + monomer 3) = 5/95 to 95/5, Furthermore, 10/90 to 90/10 are preferable. The molar ratio of monomer 1, monomer 2 and monomer 3 is as follows: monomer 1 / monomer 2 / monomer 3 = 5 to 95/3 to 90/1 to 80 / 5 to 96/3 to 80/1 to 60 (however, the total is 100) is preferable. In addition, about the monomer 2 and the monomer 3, the molar ratio and mol% shall be calculated based on an acid type compound (hereinafter the same).

  Moreover, in manufacture of the polymer A, it is preferable that the ratio of the monomer 3 shall be 1-60 mol%, and also 1-30 mol% in all the monomers used for reaction.

  The molar ratio of monomer 2 to monomer 3 is preferably monomer 2 / monomer 3 = 99/1 to 4/96, more preferably 99/1 to 5/95.

  From the viewpoint of suppressing gelation, the monomer solution containing monomer 2 and / or monomer 3 is preferably used for the reaction at a pH of 7 or less.

Hereinafter, more preferable production conditions will be described from the viewpoints of gelation suppression, adjustment of a suitable molecular weight, and performance design of a dispersant for hydraulic composition. From such a viewpoint, at the time of copolymerization, 4 mol% or more, further 6 mol% or more, particularly 8 mol% or more of the chain transfer agent is used with respect to the total number of moles of the monomers 1, 2 and 3. It is preferable. The upper limit of the amount of chain transfer agent used is preferably 100 mol% or less, more preferably 60 mol% or less, still more preferably 30 mol% or less, based on the total number of moles of monomers 1, 2 and 3. Most preferably, it can be 15 mol% or less. More specifically, (1) when r of monomer 1 is 3 to 30,
(1-1) When the total molar ratio of the monomers 1, 2 and 3 of the monomer 2 and the monomer 3 is 50 mol% or more, the chain transfer agent is the monomers 1, 2 and 3 It is preferable to use 6 to 100 mol%, particularly 8 to 60 mol%, based on the total of
(1-2) When the molar ratio in the sum of monomers 1, 2 and 3 of monomer 2 and monomer 3 is less than 50 mol%, the chain transfer agent is monomer 1, 2 and It is preferable to use 4 to 60 mol%, particularly 5 to 30 mol%, based on the total of 3.
(2) When r of monomer 1 used for polymer A is more than 30, the chain transfer agent is used in an amount of 6 to 50 mol%, particularly 8 to 40 mol%, based on monomers 1 to 3. Is preferred.

  The reaction rate of the monomers 2 and 3 is preferably 60% or more, more preferably 70% or more, more preferably 80% or more, more preferably 90% or more, and particularly preferably 95% or more. It can be selected from the viewpoint. Here, the reaction rate of the monomers 2 and 3 is calculated by the following equation.

In addition, the ratio (mol%) of the ethylenically unsaturated bond of the monomer 2 and the monomer 3 in the phosphorus-containing compound in the reaction system at the start and end of the reaction is measured by the following ¹ H-NMR. It can be calculated based on the result.
[ ¹ H-NMR conditions]
The polymer A dissolved in water and dried under reduced pressure is dissolved in deuterated methanol at a concentration of 3 to 4% by weight, and ¹ H-NMR is measured. The residual ratio of ethylenically unsaturated bonds is measured by an integral value of 5.5 to 6.2 ppm. In addition, the measurement of ¹ H-NMR uses “Mercury 400 NMR” manufactured by Varian, the number of data points is 42052, the measurement range is 6410.3 Hz, the pulse width is 4.5 μs, the pulse waiting time is 10 S, and the measurement temperature is 25.0 ° C. Perform under conditions.

  In the production of the polymer A, in addition to the monomers 1, 2, and 3, other monomers that can be copolymerized can also be used. Examples of other copolymerizable monomers include allyl sulfonic acid, methallyl sulfonic acid, any of these alkali metal salts, alkaline earth metal salts, ammonium salts, and amine salts. In addition, acrylic monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and the like, and any one or more of alkali metal salts, alkalis Anhydrous compounds such as earth metal salts, ammonium salts, amine salts, methyl esters, ethyl esters and maleic anhydride may also be used. Furthermore, (meth) acrylamide, N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, 2- (meth) acrylamide-2-metasulfonic acid, 2- (meth) acrylamide-2-ethanesulfonic acid, Examples include 2- (meth) acrylamide-2-propanesulfonic acid, styrene, styrenesulfonic acid and the like. The total proportion of monomers 1, 2, and 3 in all monomers is preferably 30 to 100 mol%, more preferably 50 to 100 mol%, particularly preferably 75 to 100 mol%, and more than 95 mol% to 100 Mol%, more preferably 97 to 100 mol%, and particularly preferably 100 mol%.

  In the production of the polymer A, monomers are preferably copolymerized in the presence of a predetermined amount of chain transfer agent. Moreover, you may use the other monomer, polymerization initiator, etc. which can be copolymerized.

  The reaction temperature of the monomers 1, 2 and 3 is preferably 40 to 100 ° C., more preferably 60 to 90 ° C., and the reaction pressure is 101.3 to 111.5 kPa (1 to 1.1 atm) in gauge pressure. 3-106.4 kPa (1-1.05 atm) is preferred.

  The pH of the reaction system can be adjusted with an inorganic acid (phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid, etc.), NaOH, KOH, triethanolamine, or the like, if necessary.

  Here, the monomer solution containing the monomer 2 and / or the monomer 3 is preferably a water-containing system (that is, the solvent contains water) for pH measurement. May be measured by adding the required amount of water. From the viewpoint of uniformity of the monomer solution, prevention of gelation, and suppression of performance degradation, the pH is preferably 7 or less, more preferably 0.1 to 6, and further preferably 0.2 to 4.5. Monomer 1 is also preferably used as a monomer solution having a pH of 7 or less. This pH is at 20 ° C.

  In the present invention, the pH at 20 ° C. of the reaction solution collected during the reaction (from the start of the reaction to the end of the reaction) is defined as the pH during the reaction. It is preferable to start the reaction under conditions that clearly show that the pH during the reaction is 7 or less (monomer ratio, solvent, other components, etc.).

  When the reaction system is non-aqueous, it can be measured by adding an amount of water capable of measuring pH to the reaction system.

In the production method of the polymer A, the monomers 1, 2 and 3 are usually reacted under the consideration of other conditions if they are reacted under the conditions exemplified in the following (1) and (2). The pH inside is considered to be 7 or less.
(1) A monomer solution having a pH of 7 or less containing all of the monomers 1, 2 and 3 is used for the copolymerization reaction of the monomers 1, 2 and 3.
(2) The copolymerization reaction of the monomers 1, 2 and 3 is started at pH 7 or less. That is, the reaction is started after the reaction system containing the monomers 1, 2 and 3 is brought to pH 7 or lower.

[Chain transfer agent]
The chain transfer agent has a function of causing a chain transfer reaction in radical polymerization (a reaction in which a growing polymer radical reacts with another molecule to move a radical active site). It is a substance to be added.

  Examples of chain transfer agents include thiol chain transfer agents and halogenated hydrocarbon chain transfer agents, and thiol chain transfer agents are preferred.

As the thiol chain transfer agent, those having a —SH group are preferable, and in particular, the general formula HS—R—Eg (wherein R represents a hydrocarbon-derived group having 1 to 4 carbon atoms, and E is − OH, —COOM, —COOR ′ or —SO ₃ M group, M represents a hydrogen atom, monovalent metal, divalent metal, ammonium group or organic amine group, and R ′ represents an alkyl having 1 to 10 carbon atoms. In which g represents an integer of 1 to 2, for example, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, Examples include octyl thioglycolate, octyl 3-mercaptopropionate, and the like from the viewpoint of chain transfer effect in a copolymerization reaction including monomers 1 to 3. Mercaptoethanol are preferable, more preferably mercaptopropionic acid. These 1 type (s) or 2 or more types can be used.

  Examples of the halogenated hydrocarbon chain transfer agent include carbon tetrachloride and carbon tetrabromide.

  Examples of other chain transfer agents include α-methylstyrene dimer, terpinolene, α-terpinene, γ-terpinene, dipentene, 2-aminopropan-1-ol and the like. A chain transfer agent can use 1 type (s) or 2 or more types.

[Polymerization initiator]
In the production method of the polymer A, it is preferable to use a polymerization initiator, and in particular, the polymerization initiator is 5 mol% or more, further 7 to 50 mol% with respect to the total number of moles of the monomers 1, 2 and 3. In particular, it is preferable to use 10 to 30 mol%.

  Examples of aqueous polymerization initiators include ammonium persulfate salt or alkali metal salt, hydrogen peroxide, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2-methylpropionamide) dihydrate, etc. These water-soluble azo compounds can be used. In addition, an accelerator such as sodium bisulfite and an amine compound can be used in combination with the polymerization initiator.

[solvent]
The production of the polymer A can be carried out by a solution polymerization method, and the solvent used at that time contains water or water and methyl alcohol, ethyl alcohol, isopropyl alcohol acetone, methyl ethyl ketone or the like. Examples of the solvent include hydrous solvents. In view of handling and reaction equipment, water is preferred. In particular, when an aqueous solvent is used, the pH of the monomer solution containing the monomer 2 and / or the monomer 3 is preferably 7 or less, more preferably 0.1 to 6, particularly 0.2 to 4. A copolymerization reaction is preferably used for the reaction in terms of uniformity of the monomer mixture (handleability), monomer reaction rate, and suppression of crosslinking by hydrolysis of the pyro compound of the phosphoric acid compound.

  An example of the manufacturing method of the polymer A is shown. A predetermined amount of water is charged into a reaction vessel, the atmosphere is replaced with an inert gas such as nitrogen, and the temperature is raised. Prepare monomer 1, monomer 2, monomer 3, chain transfer agent mixed and dissolved in water, and polymerization initiator dissolved in water, and take 0.5 to 5 hours. Drip into the reaction vessel. At that time, each monomer, chain transfer agent and polymerization initiator may be dropped separately, or a mixed solution of monomers can be charged in a reaction vessel in advance and only the polymerization initiator can be dropped. is there. That is, the chain transfer agent, the polymerization initiator, and other additives may be added as an additive solution separately from the monomer solution, or may be added to the monomer solution after being added. From the viewpoint of stability, it is preferable to supply the reaction system as an additive solution separately from the monomer solution. In any case, the pH of the solution containing the monomer 2 and / or the monomer 3 is preferably 7 or less. Further, the copolymerization reaction is preferably performed with an acid agent or the like while maintaining the pH at 7 or less, and preferably aging is performed for a predetermined time. The polymerization initiator may be added dropwise at the same time as the monomer, or may be added in portions, but it is preferable to add in portions in terms of reducing unreacted monomers. For example, in the total amount of the polymerization initiator to be finally used, 1/2 to 2/3 polymerization initiator is added simultaneously with the monomer, and the remainder is aged for 1 to 2 hours after the completion of the monomer dropping, It is preferable to add. If necessary, it is further neutralized with an alkali agent (such as sodium hydroxide) after completion of ripening to obtain the phosphate ester polymer according to the present invention. This production example is suitable as a method for producing the polymer A according to the present invention.

  The total amount of monomers 1, 2 and 3 in the reaction system and other copolymerizable monomers is preferably 5 to 80% by weight, more preferably 10 to 65% by weight, and particularly preferably 20 to 50% by weight. .

  The polymer A preferably has a weight average molecular weight (Mw) of 10,000 to 150,000. This polymer A has a Mw of 10,000 or more, preferably 12,000 or more, more preferably 13,000 or more, more preferably 14,000 or more, from the viewpoint of the expression of the dispersion effect or the viscosity reduction effect. Particularly preferably, it is 15,000 or more, and it is 150,000 or less, preferably 130,000 or less, more preferably from the viewpoints of high molecular weight by crosslinking, suppression of gelation and performance in terms of dispersion effect and viscosity reduction effect. 120,000 or less, more preferably 110,000 or less, particularly preferably 100,000 or less, and from the viewpoints of both, preferably 12,000 to 130,000, more preferably 13,000 to 120,000, More preferably, it is 14,000-110,000, Most preferably, it is 15,000-100,000. It is preferable that Mw in this range and the ratio Mw / Mn to the number average molecular weight (Mn) is 1.0 to 2.6. More preferably, it is 1.0-2.4, More preferably, it is 1.0-2.2, More preferably, it is 1.0-2.0, Most preferably, it is 1.0-1.8. Here, Mn is a number average molecular weight. Mw / Mn can be controlled by adjusting the amount of the chain transfer agent, for example. When the amount of the chain transfer agent is increased, Mw / Mn tends to decrease.

Mw and Mn of the polymer A are those measured by gel permeation chromatography (GPC) method under the following conditions. The Mw / Mn of the phosphate ester polymer in the present invention is calculated based on the peak of the polymer.
[GPC conditions]
Column: G4000PWXL + G2500PWXL (Tosoh)
Eluent: 0.2M phosphate buffer / CH ₃ CN = 9/1
Flow rate: 1.0mL / min
Column temperature: 40 ° C
Detection: RI
Sample size: 0.2mg / mL
Reference material: Polyethylene glycol equivalent

  The phosphate ester polymer satisfying Mw / Mn as described above has an appropriate branched structure by suppressing cross-linking by the monomer 3 which is a diester body, and has a structure in which adsorbing groups are densely present in the molecule. It is thought to form. Further, since the degree of dispersion Mw / Mn is controlled within a predetermined range, it approaches a system in which molecules of the same size are monodispersed, so that it is considered possible to increase the amount of adsorption on the adsorption target substance (for example, cement particles). Satisfying both of these conditions makes it possible to densely pack the substance to be adsorbed, such as cement particles, and is estimated to be effective in achieving both a dispersibility and a viscosity reducing effect.

  In addition, in the chart pattern showing the molecular weight distribution obtained by the GPC method under the above conditions, the area having a molecular weight of 100,000 or more is 5% or less of the entire area of the chart, and from the viewpoint of dispersibility of cement and darkening components Is more preferable.

<Polymer B>
The polymer B used in the present invention is an olefin-maleic acid copolymer, which is a copolymer of a chain olefin having 6 to 14 carbon atoms and maleic acid, maleic anhydride or maleate. A copolymer of a chain olefin and a mixture of maleic acid, maleic anhydride or maleate is preferred. From the viewpoint of not inhibiting the dispersion of carbons and the dispersion of cement, the olefin-derived structural unit has 6 to 14 carbon atoms, preferably 8 to 12, and particularly preferably 8 to 10. Specific examples of the polymer B include a copolymer having the following structural unit (I).

[Wherein, R represents a divalent hydrocarbon group having 6 to 14 carbon atoms, and X represents a hydrogen atom, a monovalent metal, a divalent metal, an ammonium group, or an organic ammonium group. ]

  The polymer B can use an acid type or a neutralized salt, and the degree of neutralization can also be arbitrarily selected. Therefore, X in the structural unit (I) is a hydrogen atom, a monovalent metal, a divalent metal, an ammonium group, or an organic ammonium group. The organic ammonium group is preferably an alkyl or hydroxyalkyl (C2-6) substituted ammonium group. Examples of the salt include monovalent metal salts such as alkali metal salts such as Na and K, divalent metal salts such as alkaline earth metal salts such as Ca and Mg, ammonium salts and organic ammonium salts such as alkanols (2 to 2 carbon atoms). 6) Ammonium salts are exemplified, but alkali metal salts are preferred.

  Moreover, the weight average molecular weight (gel permeation chromatography method / polystyrene sulfonic acid conversion) of the polymer B is 1000-20000, Preferably it is 2000-15000, Especially 3000-10000 are preferable. Copolymer C can be produced, for example, according to the method described in JP-A No. 51-101024.

<Polymer C>
The concrete admixture of the present invention can contain a polymer other than the polymer A and the polymer B. In particular, a polymer C obtained by copolymerizing the monomer 1 represented by the general formula (1) and the monomer 5 represented by the following general formula (5) (hereinafter referred to as polymer C). Can be included).

Wherein, R ⁵ to R ⁷ are each a hydrogen atom, a methyl group or ^{_{(CH 2) s COOM 2,}} (CH 2) s COOM 2 is COOM ¹ or another (CH _{²⁾ s} COOM ₂ and anhydrous In this case, M ¹ and M ² of those groups are not present. s represents the number of 0-2. M ¹ and M ² each represent a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkyl ammonium group, a substituted alkyl ammonium group, an alkyl group, a hydroxyalkyl group, or an alkenyl group. ]

[Monomer 1]
Regarding polymer C, in monomer 1, R ¹ and R ² in general formula (1) are each a hydrogen atom or a methyl group. R ³ is a hydrogen atom or — (CH ₂ ) _q (CO) _p O (AO) _r R ⁴ , preferably a hydrogen atom. Examples of the alkenyl of the general formula (1) include a vinyl group, an allyl group, and a methallyl group. When p is 0, AO forms an ether bond with (CH ₂ ) _q, and when p is 1, it forms an ester bond. q is 0 to 2, preferably 0 or 1, and more preferably 0. AO is an oxyalkylene group having 2 to 4 carbon atoms or an oxystyrene group, and AO is preferably an oxyalkylene group having 2 to 4 carbon atoms, more preferably an ethyleneoxy group (hereinafter referred to as EO group), and an EO group. Is 70 mol% or more, more preferably 80 mol% or more, and further preferably 90 mol% or more. r is the average added mole number of AO, and is a number of 3 to 300, preferably 5 to 120. Moreover, AO is different in an average of r repeating units, and random addition, block addition, or a mixture thereof may be included. For example, AO can contain a propyleneoxy group etc. besides EO group.

  In order for the polymer C to express the initial strength and fluidity of the concrete higher, r in the general formula (1) is preferably 50 to 300, more preferably 110 to 300, and r is 200 or less from the viewpoint of polymerizability. Since 150 or less, especially 130 or less are preferable, from a comprehensive viewpoint, r is preferably 110 to 200, more preferably 110 to 150, and particularly preferably 110 to 130. From the viewpoint of further reducing the viscosity of the concrete, r in the general formula (1) is preferably 3 to 100, and more preferably 3 to 50.

R ⁴ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, preferably 1 to 12, more preferably 1 to 4, and further preferably 1 or 2, and particularly preferably a methyl group.

  Monomer 1 includes a half-terminated alkyl-capped polyalkylene glycol such as methoxypolyethylene glycol, methoxypolypropylene glycol, methoxypolybutylene glycol, methoxypolystyrene glycol, ethoxypolyethylenepolypropyleneglycol, (meth) acrylic acid, maleic acid (half ) Esterified products, etherified products with (meth) allyl alcohol, and (meth) acrylic acid, maleic acid, and (meth) allyl alcohol adducts having 2 to 4 carbon atoms are preferably used.

  More preferred is an esterified product of alkoxy, particularly methoxypolyethylene glycol and (meth) acrylic acid. Specific examples include ω-methoxypolyoxyalkylene methacrylate and ω-methoxypolyoxyalkylene acrylate, and ω-methoxypolyoxyalkylene methacrylate is more preferable.

When the polymer C is obtained using a plurality of monomers 1 having different r, r represents an average value of the whole polymer. For example, when the polymer C is obtained using x ₁ mol% of a monomer where r = r ₁ and x ₂ mol% of a monomer where r = r ₂ , r is r = (r ₁ x ₁ + r ₂ x ₂ ) / (x ₁ + x ₂ ).

[Monomer 5]
In the monomer 5, R ^{5 to} R ⁷ in the general formula (5) are each a hydrogen atom, a methyl group, or (CH ₂ ) _s COOM ² , and (CH ₂ ) _s COOM ² is COOM ¹ or other (CH ₂ ) _s COOM ² and an anhydride may be formed. In that case, M ¹ and M ² of those groups do not exist. s represents the number of 0-2. R ⁵ is preferably a hydrogen atom, and R ⁶ is preferably a methyl group. R ⁷ is preferably a hydrogen atom or (CH ₂ ) _s COOM ² .

M ¹ and M ² are each a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, a substituted alkylammonium group, an alkyl group, a hydroxyalkyl group, or an alkenyl group. M ¹ and M ² are each preferably a hydrogen atom or an alkali metal.

  Specifically, monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid, dicarboxylic acid monomers such as maleic acid, itaconic acid and fumaric acid, or anhydrides or salts thereof (for example, alkalis) Metal salt, alkaline earth metal salt, ammonium salt, mono-, di-, trialkyl (carbon number 2 to 8) ammonium salt optionally substituted with hydroxyl group) or ester, preferably (meth) acrylic acid, Maleic acid, maleic anhydride, more preferably (meth) acrylic acid or an alkali metal salt thereof.

  Polymer C is prepared by, for example, charging water in a reaction vessel and raising the temperature, and reacting monomer 1 and monomer 5 in the presence of a chain transfer agent or the like at a constant molar ratio and weight ratio. Can be manufactured. Neutralize after aging if necessary.

  The weight ratio (monomer 1 / monomer 5) of monomer 1 and monomer 5 used for the production of polymer C is preferably 97/3 to 3/97, more preferably 95/5 to 5/95. 90/10 to 10/90 is more preferable.

The polymer C preferably has an average weight ratio (Y _I ) of the monomer 5 to all monomers for producing the polymer of 1 to 30 (% by weight). The average weight ratio is represented by [total amount of monomer 5 / total amount of all monomers used for the synthesis of polymer C] × 100 (% by weight). In order to broaden the versatility of the polymer C, it is preferable to use a polymer C ′ produced with an average weight ratio (Y _II ) different from the average weight ratio of the polymer C in combination.

The polymers C and C ′ are preferably selected so that the average weight ratio (Y _I ) and (Y _II ) differ by 2 or more. The polymers C and C ′ may be the same or different in the types of the monomer 1 and the monomer 5 used in the production, but it is preferable to use the same type.

  In the present invention, the polymer C is obtained by copolymerizing at least one monomer 1 and at least one monomer 5 and is a mole of the monomer 1 and the monomer 5. It is also possible to use a copolymer mixture in which the ratio [monomer 1] / [monomer 5] is changed at least once during the reaction [hereinafter also referred to as copolymer mixture (C)]. Such a copolymer mixture (C) changes the molar ratio [monomer 1] / [monomer 5] of monomer 1 and monomer 5 added to the reaction system at least once during the reaction. Can be manufactured. In that case, it is preferable that the difference between the maximum value and the minimum value of the molar ratio [monomer 1] / [monomer 5] is at least 0.05, particularly 0.05 to 2.5.

The copolymer mixture (C) is obtained by reacting the monomer 1 and the monomer 5 with a molar ratio of preferably [monomer 1] / [monomer 5] = 0.02-4. Although obtained, the molar ratio [monomer 1] / [monomer 5] is changed at least once during the reaction. In the present invention, the copolymer weight obtained with an average weight ratio (X _II ) different from the average weight ratio (X _I ) of the monomer 5 to the total monomers for producing the copolymer mixture (C). The combined mixture (C ′) is preferably used in combination. That is, the copolymer mixture (C ′) is a mixture of the monomer 1 and the monomer 5, preferably in a molar ratio of [monomer 1] / [monomer 5] = 0.02-4. It is a copolymer mixture obtained by the reaction, and the molar ratio [monomer 1] / [monomer 5] is changed at least once during the reaction, and the copolymer mixture (C The average weight ratio (X _II ) of the monomer 5 to the total monomers for producing ') is different from the average weight ratio (X _I ) of the copolymer mixture (C). The average weight ratio is represented by [total amount of monomers 5 / total amount of monomers] × 100 (% by weight), and preferably in the range of 1 to 30 (% by weight). The average weight ratios (X _I ) and (X _II ) are preferably at least 0.1 (% by weight), more preferably at least 0.5% by weight, and particularly at least 1.0. Even if the copolymer mixture (C) and (C ′) are different in the types of the monomer 1 and the monomer 5 used in the production, the average weight ratio (X _I ), (X _{Although II} ) may be different, it is preferable to use the same type of monomer 1 and monomer 5.

In the present invention, as monomer 5 used for polymer C, M ¹ and M ^{2 in} general formula (5) are alkyl groups (preferably having 1 to 3 carbon atoms) and hydroxyalkyl groups (preferably having 2 carbon atoms). To 5), or a polymer using a compound having an alkenyl group (preferably having 2 to 5 carbon atoms) (hereinafter referred to as polymer C ″) can be used.

  In this case, the preferable structure and type of the monomer 1 used for the production of the polymer C ″ are the same as those described above.

<Concrete admixture>
In the total solid content of the concrete admixture of the present invention, the total concentration of the polymer A and the polymer B is preferably 30 to 100% by weight, and more preferably 50 to 100% by weight.

  In the concrete admixture of the present invention, the weight ratio of the polymer A and the polymer B is preferably polymer A / polymer B = 99/1 to 60/40, more preferably 98/2 to 70/30, particularly Preferably it is 97 / 3-85 / 15.

  When the polymer C is used, the weight ratio of the polymer A to the polymer C is polymer A / polymer C = 99/1 to 20/80, more preferably 95/5 to 30/70, and particularly 90/10 to 10. 50/50 is preferred.

  In the concrete admixture of the present invention, the total of the polymer A, the polymer B, and the polymer C is preferably 50 to 100% by weight, more preferably 70 to 100% by weight, particularly preferably in the total solid content. Is 95 to 100% by weight.

  The concrete admixture of this invention can be used as a concrete skin surface darkening prevention agent.

  The concrete admixture of the present invention can also contain other additives (materials). For example, resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, alkylbenzene sulfonic acid (salt), alkane sulfonate, polyoxyalkylene alkyl (phenyl) ether, polyoxyalkylene alkyl (phenyl) ether sulfate (salt) ), Polyoxyalkylene alkyl (phenyl) ether phosphates (salts), protein materials, AE agents such as alkenyl succinic acid and α-olefin sulfonate; oxy such as gluconic acid, glucoheptonic acid, alabonic acid, malic acid, citric acid Delayers such as carboxylic acids, dextrins, monosaccharides, oligosaccharides, polysaccharides, etc .; foaming agents; thickeners; silica sand; AE water reducing agents; calcium chloride, calcium nitrite, calcium nitrate , Cal bromide Soluble calcium salts such as um, calcium iodide, chlorides such as iron chloride and magnesium chloride, sulfates, potassium hydroxide, sodium hydroxide, carbonates, thiosulfates, formic acid (salts), alkanolamines, etc. Strongening agent or accelerator; foaming agent; waterproofing agent such as resin acid (salt), fatty acid ester, oil, fat, silicone, paraffin, asphalt, wax; blast furnace slag; fluidizing agent; dimethylpolysiloxane, polyalkylene glycol fatty acid ester Anti-foaming agents such as mineral oils, fats and oils, oxyalkylenes, alcohols, amides, etc .; antifoaming agents; fly ash; melamine sulfonic acid formalin condensates, aminosulfonic acids, polymaleic acid, etc. Agent: Silica fume; Anticorrosive agent such as nitrite, phosphate, zinc oxide; Methyl cellulose, Hydroxyethyl cell Cellulose systems such as loin, natural products such as β-1,3-glucan, xanthan gum, synthetic systems such as polyacrylic acid amide, polyethylene glycol, EO adducts of oleyl alcohol or reaction products thereof with vinylcyclohexene diepoxide And water-soluble polymers such as alkyl emulsions such as alkyl (meth) acrylates.

  The concrete admixture of the present invention is preferably used at a ratio of 0.01 to 1% by weight (in terms of solid content) with respect to the hydraulic substance in the hydraulic composition, and is 0.09 to 0.4% by weight. % (In terms of solid content) is more preferable.

  The content of the polymer A in the concrete admixture of the present invention is preferably 50 to 100% by weight (in terms of solid content), more preferably 70 to 100% by weight, and particularly preferably 90 to 100% by weight.

  One or more selected from blast furnace slag, fly ash, stone powder, calcium carbonate, silica fume, and lignite (hereinafter referred to as admixture (I)) can be used in advance mixed with the concrete admixture of the present invention. For example, a powdery concrete admixture (hereinafter referred to as a powder admixture) containing the admixture (I) and the concrete admixture of the present invention, a hydraulic substance, the admixture (I), and the A powdery hydraulic composition containing a concrete admixture is obtained. At that time, the concrete admixture of the present invention to be mixed is preferably in powder form. When these powdery admixtures and hydraulic compositions are used, since it is not necessary to add an admixture during concrete preparation, the convenience is improved. In the powder admixture, the ratio of the concrete admixture of the present invention is preferably 0.001 to 1.2 wt% (in terms of solid content), more preferably 0.01 to 0.6 wt% in the powder admixture. %, Particularly preferably 0.02 to 0.3% by weight. Moreover, in the said powdery hydraulic composition, the ratio of the concrete admixture of the present invention is preferably 0.0001 to 0.4% by weight (in terms of solid content) with respect to the hydraulic substance, more preferably 0.8. It is 001 to 0.2% by weight, particularly preferably 0.002 to 0.1% by weight.

  From the standpoint of the cement dispersibility of the admixture of the present invention and the remarkable effect of suppressing darkening of the concrete surface, the water / hydraulic substance ratio (wt%) of the hydraulic composition is preferably 45 wt% or less, more preferably. It is 45 to 20% by weight, particularly preferably 40 to 20% by weight. Moreover, also when using the polymer B as a concrete skin | surface darkening inhibitor with respect to the hydraulic composition containing the polymer A, a hydraulic composition from the point of the remarkable of a cement dispersibility and a concrete skin darkening inhibitory effect. The water / hydraulic substance ratio (wt%) of the product is preferably 45 wt% or less, more preferably 45 to 20 wt%, particularly preferably 40 to 20 wt%.

  The polymer A and the polymer B can be blended in the hydraulic composition to prevent darkening of the resulting concrete skin surface. In blending, the polymer A and the polymer B may be added separately. Suitable values of the blending amounts and blending ratios of the polymers A and B are the same as those of the concrete admixture containing the polymers A and B.

  According to the present invention, a hydraulic composition containing 0.006 to 1% by weight (in terms of solid content) of a hydraulic substance and a polymer A or a mixture of the polymer A and the polymer C with respect to the hydraulic substance. There is provided a method for preventing darkening of the skin surface of the concrete, which comprises a step of adding the polymer B at a ratio of 0.0001 to 0.4% by weight (in terms of solid content) with respect to the hydraulic substance. The

  The hydraulic composition targeted by the admixture of the present invention is cement paste, mortar, concrete or the like mainly composed of cement, and is not particularly limited, but particularly contains a lot of black fine powder, blast furnace slag, fly It is preferably used for a hydraulic composition containing ash, stone powder, calcium carbonate, silica fume and lignite. Furthermore, it is preferably used for self-filling concrete having high fluidity containing these powders, and a mortar flow (according to the physical test method of JIS R-5201 cement, without tapping) may include an area of 180 to 400 mm. It is done. A hardened concrete body using this hydraulic composition is excellent in aesthetics because it prevents blackening of the surface even when it contains a material containing a large amount of black fines.

  The hydraulic composition that is the target of the admixture of the present invention contains a hydraulic substance such as a hydraulic powder. The hydraulic powder is a powder having physical properties that are cured by a hydration reaction. For example, cement and gypsum. Preferred are ordinary Portland cement, Belite cement, medium heat cement, early strong cement, super early strong cement, sulfate resistant cement, etc., and blast furnace slag, fly ash, silica fume, stone powder (calcium carbonate powder), etc. May be added. In addition, the hydraulic composition finally obtained by adding sand, sand and gravel as aggregates to these powders is generally called mortar, concrete, etc., respectively. The admixture of the present invention is for ready-mixed concrete, concrete vibration product field, self-leveling, refractory, plaster, gypsum slurry, lightweight or heavy concrete, AE, repair, prepacked, for trayy, It is useful in any field of various concrete such as grout, ground improvement, and cold.

  The method for adding to the hydraulic substance is not limited, and may be any of mixing the concrete admixture of the present invention in advance, separate addition, addition to the mixed water, simultaneous mixing, midway, or addition before completion. The concrete admixture can be either liquid or powder.

  Various materials (agents) can be used for the hydraulic composition of the present invention. For example, resin soap, saturated or unsaturated fatty acid, lauryl sulfate, alkylbenzene sulfonic acid (salt), alkane sulfonate and other AE agents; gluconic acid, citric acid and other oxycarboxylic acids, dextrin, sugar alcohols and other retarders; Foaming agent; thickener; silica sand; AE water reducing agent; early strengthening agent or accelerator; foaming agent; waterproofing agent; fluidizing agent; dimethylpolysiloxane, polyalkylene glycol fatty acid ester, mineral oil, fat and oil, oxy Anti-foaming agents such as alkylene-based, alcohol-based, and amide-based; anti-foaming agents; high-performance water reducing agents such as melamine sulfonic acid formalin condensate-based, aminosulfonic acid-based, polycarboxylic acid-based, polymaleic acid-based; Water-soluble polymers such as methylcellulose and hydroxyethylcellulose; Polymer emulsions such as alkyl (meth) acrylate And the like. Moreover, you may mix | blend the said component in the concrete admixture of this invention or a concrete skin darkening prevention agent.

Production example A
366 g of water was charged into a glass reaction vessel (four-necked flask) equipped with a stirrer, and was purged with nitrogen while stirring. 450 g of ω-methoxypolyethyleneglycol monomethacrylate (average added mole number of ethylene oxide 23) (effective part 60.8% by weight, moisture 35% by weight), phosphoric acid mono-[(2-hydroxyethyl) methacrylic acid] ester and phosphorus A mixture of 71.6 g of phosphoric acid ester (A) which is a mixture of acid di-[(2-hydroxyethyl) methacrylic acid] ester and 4.5 g of 3-mercaptopropionic acid and 8.4 g of ammonium persulfate in 48 g of water Two of those dissolved in each were added dropwise over 1.5 hours. After aging for 1 hour, 1.8 g of ammonium persulfate dissolved in 10 g of water was added dropwise over 30 minutes, and then aging was carried out at the same temperature (80 ° C.) for 1.5 hours. After completion of aging, the mixture was neutralized with 44.4 g of a 32% aqueous sodium hydroxide solution to obtain a polymer a-1 having a weight average molecular weight of 35,000. (Monomer polymerization pH: 1.0, reaction rate 100%)

The phosphoric acid ester (A) used in this production example was charged with 200 g of 2-hydroxyethyl methacrylate and 36.0 g of 85% phosphoric acid (H ₃ PO ₄ ) in a reaction vessel. 89.1 g of phosphoric anhydride (P ₂ O ₅ ) was gradually added while cooling so that the temperature did not exceed 60 ° C. After completion, the reaction temperature was set to 80 ° C., reacted for 6 hours, and cooled. This phosphate esterified product (A) was also used in some of the following production examples.

  The polymers a-2 to a-7 in Table 1 were also synthesized according to Production Example A using the charging ratios shown in Table 1.

  However, in the polymers a-4 and a-5, ω-methoxypolyethylene glycol monomethacrylate (average added mole number of ethylene oxide 9) was used as the monomer 1.

  Further, the polymer a-6 was obtained by using ω-methoxypolyethylene glycol monomethacrylate as monomer 1 (average added mole number of ethylene oxide 9: NK ester M90G manufactured by Shin-Nakamura Chemical Co., Ltd.) and monomers 2 and 3 as monophosphate monophosphate. Using a mixture of [[2-hydroxyethyl) methacrylic acid] ester and di-[(2-hydroxyethyl) methacrylic acid] ester (Phosmer M: Unichemical Co., Ltd.) A mixed solution containing the same dissolved in water as the monomer 1 was dropped.

  Further, the polymer a-7 had ω-methoxypolyethyleneglycol monomethacrylate as monomer 1 (average added mole number of ethylene oxide 23: NK ester M230G manufactured by Shin-Nakamura Chemical Co., Ltd.), and monomer 2 and 3 as phosmer M: Using Unichemical Co., Ltd., a mixture of monomers 1 to 3 dissolved in water having the same weight as monomer 1 was added dropwise.

Production example B
A mixture of 116 parts by weight of maleic acid (1 mole), 86 parts by weight of C ₆ olefin (1 mole), 4 parts of benzoyl peroxide and 400 parts of toluene was mixed at 70 to 75 ° C. for 8 hours in a nitrogen atmosphere in an autoclave. Polymerized. After completion of the polymerization, the precipitated copolymer was separated by filtration and dried to obtain a copolymer. To 620 g of water and 202 g (1 mol) of copolymer, 266 g of 30% sodium hydroxide (2 mol of sodium hydroxide) was added and stirred at 80 ° C. until it was dissolved transparently. b-1 was obtained. Copolymer No. b2-1 to b-2-4, b-3 to b-5, and Comparatives 1 to 3 were also produced according to this method. In this production, the molecular weight was adjusted with the amount of benzoyl peroxide.

Production Example C1
A glass reaction vessel (four-necked flask) equipped with a stirrer was charged with 281.4 g of water, purged with nitrogen while stirring, and heated to 80 ° C. in a nitrogen atmosphere. ω-methoxypolyethyleneglycol methacrylate (added mole number of ethylene oxide 120) 336.5 g, methacrylic acid 22.2 g and 2-mercaptoethanol 1.89 g dissolved in water 238.2 g and ammonium persulfate 3.68 g 45 g water Two of those dissolved in each were added dropwise over 1.5 hours. Subsequently, a solution prepared by dissolving 1.47 g of ammonium persulfate in 15 g of water was added dropwise over 30 minutes, and then aged at the same temperature (80 ° C.) for 1 hour. After completion of the aging, the mixture was neutralized with 18.7 g of 48% sodium hydroxide to obtain a copolymer c-1. (Weight average molecular weight 79000)

Production Example C2
A glass reaction vessel (four-necked flask) equipped with a stirrer was charged with 246.4 g of water, purged with nitrogen while stirring, and heated to 56 ° C. in a nitrogen atmosphere. A mixture of 148.8 g of ω-methoxypolyethylene glycol methacrylate (addition mole number of ethylene oxide 10), 39.2 g of methacrylic acid and 2.32 g of 3-mercaptopropionic acid, and 43.3 g of 5% aqueous solution of ammonium persulfate. Each was added dropwise over 1.5 hours. Thereafter, aging was performed at the same temperature (56 ° C.) for 3 hours. After completion of aging, the mixture was neutralized with 48% sodium hydroxide to pH = 6 to obtain a copolymer c-2. (Weight average molecular weight 34000)

  The monomers of polymer A, polymer B and polymer C, mol%, etc. are summarized in Tables 1-3.

<Examples 1-12 and Comparative Examples 1-7>
Concrete admixtures were prepared using the polymer A, polymer B, and polymer C, and the following mortar formulation was evaluated. The results are shown in Table 4.

(Formulation 1)
Cement [manufactured by Taiheiyo Cement Co., Ltd .; ordinary Portland cement] 300 g, fly ash [JIS II; ignition loss 3.9%] 300 g, Seto Inland sea sand 800 g, water 175 g, antifoaming agent ; Foam Rex 797] 0.01 g, Polymer A, Polymer B and Polymer C are kneaded with a mortar mixer. At that time, according to the physical test method of JIS R-5201 cement, the addition amounts of the polymer A, the polymer B, and the polymer C were adjusted so that the mortar flow was 260 to 300 mm. The combinations and addition amounts of the polymers are as shown in Table 4. In Table 4, the addition amount is the weight percent of cement as an effective component of polymer A, polymer B and polymer C.

(Formulation 2)
Cement [manufactured by Taiheiyo Cement Co., Ltd .; ordinary Portland cement] 500 g, silica fume [manufactured by Kao Corporation; Micropoz] 50 g, Seto Inland sea sand 800 g, water 175 g, antifoaming agent [manufactured by Nikka Chemical Co., Ltd .; foam Rex 797] 0.01 g, polymer A, polymer B and polymer C are kneaded with a mortar mixer. Thereafter, a mortar was prepared in the same manner as Formulation 1.

<Reference example>
Cement [manufactured by Taiheiyo Cement Co., Ltd .; ordinary Portland cement] 300 g, fly ash [JIS II; loss on ignition 2.1%] 200 g, Seto Inland sea sand 800 g, water 170 g, defoaming agent [manufactured by Nikka Chemical Co., Ltd.] ; Foam Rex 797] 0.01 g, and the polymer B and the polymer C are kneaded in a mortar mixer in the same combination as in Comparative Example 3. At that time, according to the physical test method of JIS R-5201 cement, the addition amounts of the polymer B and the polymer C were adjusted so that the mortar flow was 260 to 300 mm. The addition amount is as shown in Table 4. In Table 4, the addition amount is the weight percent of cement as an effective component of polymer B and polymer C. In the blend of this reference example, the content of the black fine powder is less than the blend 1.

(Performance evaluation)
After kneading, the mortar is filled into a mold (similarly JIS R-5201), further vibration [25 times tapping (1 time / 1 second)] is applied, and then it is cured at 20 ° C. for 24 hours, and the appearance is photographed. The darkened portion was judged by visual observation, the photograph was binarized, and the area of the darkened portion relative to the total area was obtained by image analysis, and was defined as the darkened area ratio. Then, darkening was evaluated according to the following criteria.
Blackening criteria: ◎ No blackening, ○ Blackening area ratio 5% or less, △ Blackening area ratio 5% to 10% or less, × Blackening area ratio 10% or more

Claims (6)

Weight obtained by copolymerizing monomer 1 represented by general formula (1), monomer 2 represented by general formula (2), and monomer 3 represented by general formula (3) Polymer A having an average molecular weight of 10,000 to 150,000 and a polymer having a weight average molecular weight of 1,000 to 20,000 obtained by copolymerizing olefin having 6 to 14 carbon atoms with maleic acid, maleic anhydride or maleate A concrete admixture containing B in a weight ratio of polymer A / polymer B = 99/1 to 60/40 ,
Polymer A comprises monomer 1, monomer 2 and monomer 3, monomer 1 / monomer 2 / monomer 3 = 5 to 95/3 to 90/1 to 80 (provided that The total ratio is 100), and the monomer 2 and the monomer 3 are mixed in a molar ratio of monomer 2 / monomer 3 = 99/1 to 4/96 and used in the reaction. In the monomer, the ratio of the monomer 3 is 1 to 60 mol%, a copolymer obtained by copolymerization,
Used for concrete containing one or more selected from blast furnace slag, fly ash, stone powder, calcium carbonate, silica fume and lignite,
Concrete admixture .

[In the formula, R ¹ and R ² are each a hydrogen atom or a methyl group, R ³ is a hydrogen atom, or — (CH ₂ ) _q (CO) _p O (AO) _r R ⁴ , and AO has 2 to 4 carbon atoms. An oxyalkylene group or an oxystyrene group, p is a number of 1 , q is a number of 0 to 2, p and q are not simultaneously 0, r is an average added mole number of AO, a number of 3 to 300, R ⁴ Represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. ]

[Wherein R ¹¹ is a hydrogen atom or a methyl group, R ¹² is an alkylene group having 2 to 12 carbon atoms, m1 is a number of 1 to 30, M ³ and M ⁴ are a hydrogen atom, an alkali metal or an alkaline earth metal, respectively. Represents. ]

[Wherein R ¹³ and R ¹⁵ are each a hydrogen atom or a methyl group, R ¹⁴ and R ¹⁶ are each an alkylene group having 2 to 12 carbon atoms, m2 and m3 are each a number of 1 to 30 and M ⁵ is Represents a hydrogen atom, an alkali metal or an alkaline earth metal. ] A concrete admixture containing at least one member selected from blast furnace slag, fly ash, stone powder, calcium carbonate, silica fume and lignite and the concrete admixture according to claim 1 . A hydraulic composition comprising a hydraulic substance, one or more selected from blast furnace slag, fly ash, stone powder, calcium carbonate, silica fume, and lignite, and the concrete admixture according to claim 1 . The ratio of the polymer A to the hydraulic substance is 0.006 to 1% by weight (solid content conversion), and the polymer B is the hydraulic substance to the ratio of 0.0001 to 0.4% by weight (solid content conversion). The hydraulic composition of Claim 3 to contain. A hardened concrete body using the hydraulic composition according to claim 3 or 4. Weight obtained by copolymerizing monomer 1 represented by general formula (1), monomer 2 represented by general formula (2), and monomer 3 represented by general formula (3) Polymer A having an average molecular weight of 10,000 to 150,000 and a polymer having a weight average molecular weight of 1,000 to 20,000 obtained by copolymerizing olefin having 6 to 14 carbon atoms with maleic acid, maleic anhydride or maleate the B, blast furnace slag, fly ash, stone powder, calcium carbonate, one or more selected from silica fume and lignite, a darkening method of preventing concrete skin surface to be blended into a composition containing a hydraulic substance and water,
Polymer A comprises monomer 1, monomer 2 and monomer 3, monomer 1 / monomer 2 / monomer 3 = 5 to 95/3 to 90/1 to 80 (provided that The total ratio is 100), and the monomer 2 and the monomer 3 are mixed in a molar ratio of monomer 2 / monomer 3 = 99/1 to 4/96 and used in the reaction. In the monomer, the ratio of the monomer 3 is 1 to 60 mol%, a copolymer obtained by copolymerization,
The polymer A is 0.006 to 1% by weight (in terms of solid content) with respect to the hydraulic material, the polymer B is 0.0001 to 0.4% by weight (in terms of solid content) with respect to the hydraulic material, and the weight Blend A / polymer B = 99/1 to 60/40 in a weight ratio,
How to prevent darkening of the concrete surface .

[In the formula, R ¹ and R ² are each a hydrogen atom or a methyl group, R ³ is a hydrogen atom, or — (CH ₂ ) _q (CO) _p O (AO) _r R ⁴ , and AO has 2 to 4 carbon atoms. An oxyalkylene group or an oxystyrene group, p is a number of 1 , q is a number of 0 to 2, p and q are not simultaneously 0, r is an average added mole number of AO, a number of 3 to 300, R ⁴ Represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms. ]

[Wherein R ¹¹ is a hydrogen atom or a methyl group, R ¹² is an alkylene group having 2 to 12 carbon atoms, m1 is a number of 1 to 30, M ³ and M ⁴ are a hydrogen atom, an alkali metal or an alkaline earth metal, respectively. Represents. ]

[Wherein R ¹³ and R ¹⁵ are each a hydrogen atom or a methyl group, R ¹⁴ and R ¹⁶ are each an alkylene group having 2 to 12 carbon atoms, m2 and m3 are each a number of 1 to 30 and M ⁵ is Represents a hydrogen atom, an alkali metal or an alkaline earth metal. ]