JP2023134481A - Polymer and cement additive - Google Patents

Abstract

To provide a water-soluble polymer suitable for a cement additive, a cement additive excellent in water-reducing performance, a cement composition excellent in flowability, and cement obtained by hardening a cement composition.SOLUTION: A polymer comprises a structural unit derived from general formula (II) and a structural unit derived from the general formula (III). [In the formula (II), R5, R6, and R7 independently represent H or a methyl group, M represents at least one selected from the group consisting of H, a monovalent metal atom, a bivalent metal atom and ammonium]. [In the formula (III), R8 and R9 independently represent H or a C1-6 alkyl group, Rb and Rc independently represent a C2-18 alkylene group. l represents any integer of 0-4, and m represents any integer of 1-200].SELECTED DRAWING: None

Description

The present invention relates to polymers and cement admixtures. More specifically, the present invention relates to a polymer that can be suitably used in cement compositions such as cement paste, mortar, and concrete, and a cement admixture containing the same.

Cement admixtures are used to reduce water content and improve fluidity of cement compositions such as cement paste, mortar, and concrete. Cement admixtures are required to have not only water-reducing performance, but also workability during building construction, and quality such as strength and durability of the cured product, so various studies are currently being conducted.

Conventionally, water reducing agents such as naphthalene-based water reducing agents have been used as cement admixtures, but on the other hand, polycarboxylic acid-based water reducing agents containing (poly)oxyalkylene chains have been proposed. The (poly)oxyalkylene chain acts as a dispersing group that disperses cement particles due to its steric repulsion, and is therefore effective in improving the fluidity of the cement composition.

As a polycarboxylic acid water reducing agent containing a (poly)oxyalkylene chain, for example, a polycarboxylic acid obtained by reacting ethylene oxide or the like with the hydroxyl group of methallyl alcohol or 3-methyl-3-buten-1-ol. Water reducing agents have been reported (Patent Documents 1 and 2).

Japanese Patent Application Publication No. 2015-157761 JP2014-166948A

The polycarboxylic acid water reducing agent containing a (poly)oxyalkylene chain has one (poly)oxyalkylene chain in the corresponding monomer. However, when these polymers are used for the purpose of controlling qualities such as the water-reducing performance of cement admixtures and the fluidity of cement compositions, the content of (poly)oxyalkylene chains in the monomers ( Since it depends on the degree of polymerization of the poly)oxyalkylene group, there is no other way than to control this degree of polymerization. Therefore, there is little freedom in designing and blending cement compositions using cement admixtures containing these polymers, and there are limits to improving performance such as fluidity of cement compositions.

The present invention was made in view of the above-mentioned problems, and provides a water-soluble polymer suitable for a cement admixture, a cement admixture with excellent water-reducing performance, a cement composition with excellent fluidity, and a hardening of the cement composition. The purpose is to provide cement made by

As a result of extensive studies, the present inventors have found that the water-reducing performance of cement admixtures can be improved by using a polymer whose monomer is a compound having two or more (poly)oxyalkylene chains in the molecule. Furthermore, they discovered that the fluidity of a cement composition can be improved by using the cement water reducing agent in the cement composition, and based on this knowledge, they conducted further studies and completed the present invention.

The present invention provides the following [1] to [11].
[1] A polymer containing a structural unit derived from the following general formula (I) and a structural unit derived from the following general formula (II).
[In general formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and R _a represents an alkylene group having 2 to 18 carbon atoms. n represents any integer from 0 to 3, o represents any integer from 1 to 200, and p represents any integer from 1 to 3. ]
[In general formula (II), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or a methyl group, and M is a group consisting of a hydrogen atom, a monovalent metal atom, a divalent metal atom, and ammonium represents at least one selected from ]
[2] A polymer containing a structural unit derived from general formula (II) and a structural unit derived from general formula (III) below.
[In general formula (III), R ⁸ and R ⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R _b and R _c each independently represent an alkylene group having 2 to 18 carbon atoms. represents. l represents any integer from 0 to 4, and m represents any integer from 1 to 200. ]
[3] The polymer according to [1], further comprising a structural unit derived from general formula (III).
[4] In general formula (II), M is at least one selected from the group consisting of a hydrogen atom, a monovalent metal atom, and a divalent metal atom, according to any one of [1] to [3] polymer.
[5] In general formula (I), R ¹ , R ² and R ⁴ are hydrogen atoms, R ³ is a methyl group, R _a is an ethylene group, n is 1, and p is 2 or 3. The polymer according to any one of [1], [3], and [4].
[6] The polymer according to any one of [2] to [5], wherein in general formula (III), R ⁸ and R ⁹ are hydrogen atoms, R _b and R _c are ethylene groups, and l is 2. Combined.
[7] A cement admixture containing the polymer according to any one of [1] to [6].
[8] A cement composition comprising the cement admixture according to [7].
[9] Concrete obtained by curing the cement composition according to [8].
[10] A compound represented by the following general formula (IV).
[In general formula (IV), o represents any integer from 1 to 200, and p is 2 or 3. ]
[11] A compound represented by the following general formula (V).
[In the general formula (V), R _b and R _c each independently represent an alkylene group having 2 to 18 carbon atoms. l represents any integer from 0 to 4, and m represents any integer from 1 to 200. ]

According to the present invention, there are provided a water-soluble polymer suitable as a cement admixture, a cement admixture with excellent water-reducing performance, a cement composition with excellent fluidity, and concrete made by hardening the cement composition.

[Polymer]
The present invention is a polymer containing a structural unit derived from the following general formula (I) and a structural unit derived from the following general formula (II), and this polymer has particularly excellent solubility in water and can be used in cement compositions. It has excellent miscibility with

In general formula (I), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom, a methyl group or an ethyl group, and R _a represents an alkylene group having 2 to 18 carbon atoms. n represents any integer from 0 to 3, o represents any integer from 1 to 200, and p represents any integer from 1 to 3.

In general formula (I), examples of the alkylene group having 2 to 18 carbon atoms include ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, and n-octylene group. group, linear alkylene groups such as n-nonylene group, n-decylene group, branched alkylene groups such as 2-methylpropylene group, 2-methylhexylene group, tetramethylethylene group, etc. These may contain one type or two or more types.

In general formula (I), o is the average number of added moles of the oxyalkylene group (R _a O). The average number of moles added is 1 to 200, preferably 1 to 80, more preferably 4 to 70, still more preferably 4 to 70, particularly preferably 4 to 60. If o is less than 1, sufficient cement dispersion performance will not be exhibited, which is not preferable. On the other hand, if o exceeds 200, the cement composition tends to have high viscosity and become difficult to handle. In addition, in this specification, the "average number of moles added" refers to the arithmetic average value of the number of moles of oxyalkylene groups added in 1 mole of each component of general formula (I) and general formula (III) described below. means. Further, when o is a number of 2 or more, two or more oxyalkylene groups represented by R _a O in the general formula (I) are necessarily present in the same compound, but two or more oxyalkylene groups When having an alkylene group, each may have any form such as random, block, alternating, etc.

In general formula (I), R ¹ , R ² and R It is preferable that ⁴ is a hydrogen atom, R ³ is a methyl group, R _a is an ethylene group, n is 1, and p is 2 or 3.

In order to introduce a structural unit derived from general formula (I) into a polymer, it is preferable to use a compound represented by the following general formula (IV). By using this compound, it is possible to improve productivity due to its excellent volumetric efficiency, and it is possible to introduce two oxyalkylene groups into one molecule while maintaining the reactivity of the double bond portion during polymerization.

In the general formula (IV), o represents any integer from 1 to 200, and p is 2 or 3.

In general formula (II), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or a methyl group, and M is selected from the group consisting of a hydrogen atom, a monovalent metal atom, a divalent metal atom, and ammonium. Represents the selected one. That is, general formula (II) forms an ion pair.

In general formula (II), examples of monovalent metal atoms include alkali metal atoms such as lithium, sodium, and potassium, and examples of divalent metal atoms include alkaline earth metal atoms such as calcium and magnesium. It will be done.

In general formula (II), ammonium is a molecular monovalent cation containing a nitrogen atom, and may also contain a hydrogen atom. Examples of such ammonium include alkylammoniums such as methylammonium, ethylammonium, dimethylammonium, diethylammonium, trimethylammonium, and triethylammonium; ethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine; Examples include alkanol ammoniums such as hydroxyethyldiisopropanolamine, dihydroxyethylisopropanolamine, tetrakis(2-hydroxypropyl)ethylenediamine, and pentakis(2-hydroxypropyl)diethylenetriamine.

In general formula (II), from the viewpoint of availability, M is preferably one selected from the group consisting of a hydrogen atom, a monovalent metal atom, and a divalent metal atom, and M is a hydrogen atom or a sodium atom. It is more preferable that there be.

Specific examples of the unsaturated carboxylic acid monomer represented by general formula (II) include acrylic acid, methacrylic acid, sodium acrylate, sodium methacrylate, ammonium acrylate, ammonium methacrylate, etc. Two or more types may be used in combination.

As the unsaturated carboxylic acid monomer, (meth)acrylic acid is preferably used, and methacrylic acid is most preferably used. Commercially available compounds may be used as these compounds.

The present invention is a polymer containing a structural unit derived from the above general formula (II) and a structural unit derived from the following general formula (III), and this polymer has particularly excellent solubility in water and can be used in cement compositions. It has excellent miscibility with

In general formula (III), R ⁸ and R ⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R _b and R _c each independently represent an alkylene group having 2 to 18 carbon atoms. represent. l represents any integer from 0 to 4, and m represents any integer from 1 to 200.

In the present invention, examples and preferred embodiments of general formula (II) are the same as those of a polymer containing a structural unit derived from the above general formula (I) and a structural unit derived from the following general formula (II).

In general formula (III), examples of the alkyl group having 1 to 6 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, tert-butyl group, pentyl group, and hexyl group.

In general formula (III), the alkylene group having 2 to 18 carbon atoms includes ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group. group, linear alkylene groups such as n-nonylene group, n-decylene group, branched alkylene groups such as 2-methylpropylene group, 2-methylhexylene group, tetramethylethylene group, etc. These may contain one type or two or more types.

In the general formula (III) and the general formula (V) described below, m is the average number of added moles of oxyalkylene groups (R _b O and R _c O). The average number of moles added is a number of 1 to 200, preferably a number of 1 to 80, more preferably a number of 4 to 70, still more preferably a number of 4 to 70, even more preferably The number is from 4 to 60. If m is less than 1, sufficient cement dispersion performance will not be exhibited, which is not preferable. On the other hand, if m exceeds 200, the cement composition tends to have high viscosity and become difficult to handle. Each of the oxyalkylene groups represented by R _b O and R _c O may have any addition form such as random addition, block addition, or alternating addition.

In general formula (III), from the viewpoint of having sufficient polymerizability and introducing two oxyalkylene groups in one molecule, R ⁸ and R ⁹ are each independently a hydrogen atom or a carbon atom having 1 to 6 carbon atoms. An alkyl group is preferred, each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms is more preferred, each independently a hydrogen atom or an alkyl group having 1 to 2 carbon atoms is even more preferred, and a hydrogen atom is even more preferred.

In general formula (III), from the viewpoint of availability of raw materials, it is preferable that R ⁸ and R ⁹ are hydrogen atoms, R _b and R _c are ethylene groups, and l is 2.

In order to introduce a structural unit derived from general formula (III) into a polymer, it is preferable to use a compound represented by the following general formula (V). By using this compound, two oxyalkylene groups can be introduced per molecule while having sufficient polymerizability, and a polymer with a high density of oxyalkylene groups can be obtained.

In general formula (V), R _b and R _c each independently represent an alkylene group having 2 to 18 carbon atoms. l represents any integer from 0 to 4, and m represents any integer from 1 to 200.

The monomer represented by general formula (I) or general formula (III) can be manufactured by various methods, and a typical manufacturing method is as shown below.
Unsaturated diols having an alkenyl group having 2 to 10 carbon atoms, such as 2-(1-methylethenyl)-1,3-propanediol and 3-methylene-1,5-pentanediol, are combined with potassium hydroxide and hydroxide. General formula (I) or general formula ( A monomer represented by III) can be obtained.

In addition to general formulas (I) and (II), the polymer of the present invention may further contain a structural unit derived from (III). By containing these structural units, the polymer has excellent water solubility. can get.

The polymer of the present invention essentially contains a monomer represented by general formula (I) or general formula (III), and an unsaturated carboxylic acid monomer represented by general formula (II). Although it can be produced by copolymerization, the production method is not limited thereto. For example, instead of monomers containing unsaturated (poly)oxyalkylene chains, unsaturated monomers before addition of alkylene oxide, such as 2-(1-methylethenyl)-1,3-propanediol Using alcohol, this is copolymerized with unsaturated carboxylic acid monomers in the presence of a polymerization initiator, and if necessary, other monomers that can be copolymerized with these monomers are further copolymerized. It can also be obtained by adding an average of 1 to 200 moles of alkylene oxide. The above copolymerization reaction can be carried out using a common polymerization initiator, and can be carried out by methods such as polymerization in a solvent or bulk polymerization.

Polymerization in the above solvents can be carried out either continuously or batchwise, and the solvents used in this case include water; lower alcohols such as methanol, ethanol, and isopropyl alcohol; benzene, toluene, xylene, cyclohexane, n. Aromatic or aliphatic hydrocarbons such as hexane; ester compounds such as ethyl acetate; and ketone compounds such as acetone and methyl ethyl ketone are preferred. These may be used alone or in combination of two or more. In view of the solubility of the raw material monomer and the obtained polymer, and the solubility of the above polymer during use, it is preferable to use at least one selected from the group consisting of water and lower alcohols having 1 to 4 carbon atoms. .

When performing aqueous polymerization, examples of radical polymerization initiators include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; 2,2'-azobis-2-methylpropionamidine hydrochloride, etc. azoamidine compounds, cyclic azoamidine compounds such as 2,2'-azobis-2-(2-imidazolin-2-yl)propane hydrochloride, and azonitrile compounds such as 2-carbamoylazoisobutyronitrile. In this case, alkali metal sulfites such as sodium bisulfite, Fe(II) salts such as metabisulfite, sodium hypophosphite, Mohr's salt, sodium hydroxymethanesulfinate dihydrate, hydroxyl Accelerators such as amine hydrochloride, thiourea, L-ascorbic acid (salt), and erythorbic acid (salt) can also be used in combination. Note that when hydrogen peroxide is used as a water-soluble polymerization initiator, it is preferably used in combination with a promoter such as L-ascorbic acid (salt).

In addition, 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; Azo compounds such as bisisobutyronitrile are used as polymerization initiators. At this time, a promoter such as an amine compound can also be used in combination. Furthermore, when a water-lower alcohol mixed solvent is used, it can be appropriately selected from among the various polymerization initiators or combinations of polymerization initiators and accelerators described above. The polymerization temperature is appropriately determined depending on the solvent and polymerization initiator used, but it is usually carried out at 0 to 120°C.

The above bulk polymerization is carried out at a temperature of 50 to 200°C using a peroxide such as benzoyl peroxide or lauroyl peroxide; a hydroperoxide such as cumene hydroperoxide; or an azo compound such as azobisisobutyronitrile as a polymerization initiator. It will be held in

The method of charging each monomer into the reaction vessel is not particularly limited, and there are methods such as initially charging the entire amount into the reaction container at once, dividing the entire amount into the reaction container or continuously charging it, and charging a portion of the monomer into the reaction container initially. , the remainder may be divided into reaction vessels or continuously introduced into the reaction vessel. Preferred feeding methods include, specifically, methods (1) to (4) below.
(1) A method in which all monomers are continuously introduced into a reaction vessel.
(2) A method in which all of the monomer containing an unsaturated (poly)oxyalkylene chain is initially charged into a reaction vessel, and all of the other monomers are continuously charged into the reaction vessel.
(3) Part of the monomer containing unsaturated (poly)oxyalkylene chains is initially charged into the reaction vessel, and the remaining monomer containing unsaturated (poly)oxyalkylene chains and other monomers are A method in which the entire body is continuously thrown into a reaction container.
(4) Part of the monomer containing unsaturated (poly)oxyalkylene chains and part of the other monomers are initially charged into a reaction vessel, and the monomer containing unsaturated (poly)oxyalkylene chains is A method in which the remainder of the monomer and the remainder of the other monomers are added to the reaction vessel alternately in several portions. Furthermore, by continuously or stepwise changing the rate at which each monomer is introduced into the reaction vessel during the reaction, the mass ratio of each monomer introduced per unit time can be changed continuously or stepwise to achieve co-operation. A mixture of copolymers having different ratios of constituent units in the polymer may be synthesized during the polymerization reaction. Note that 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 depending on the purpose.

A chain transfer agent can also be used in combination to adjust the molecular weight of the resulting polymer. Examples of chain transfer agents include thiol-based chain transfer agents such as mercaptoethanol, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, and 2-mercaptoethanesulfonic acid; secondary alcohols such as isopropyl alcohol; and phosphorous acid. , hypophosphorous acid and its salts (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite and its salts (sodium sulfite, sodium hydrogen sulfite, dithionite) Known hydrophilic chain transfer agents such as lower oxides of sodium chloride, sodium metabisulfite, etc. and salts thereof can be used. Furthermore, the use of hydrophobic chain transfer agents is effective in improving the viscosity of cement compositions. Examples of hydrophobic chain transfer agents include those having 3 or more carbon atoms such as butanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexylmercaptan, thiophenol, octyl thioglycolate, octyl 3-mercaptopropionate, etc. It is preferable to use a thiol-based chain transfer agent having a hydrocarbon group of It is also possible to use two or more types of chain transfer agents in combination, and a hydrophilic chain transfer agent and a hydrophobic chain transfer agent may be used in combination. Furthermore, in order to adjust the molecular weight of the polymer, it is also effective to use monomers with high chain transfer properties such as (meth)allylsulfonic acids (salts) as the other copolymerizable monomers. be.

In the above polymerization, in order to obtain a polymer with a predetermined molecular weight with good reproducibility, it is necessary to allow the polymerization reaction to proceed stably. Therefore, when performing solution polymerization, the dissolved oxygen concentration of the solvent used at 25°C is preferably 5 ppm or less. More preferably 0.01 to 4 ppm, still more preferably 0.01 to 2 ppm, most preferably 0.01 to 1 ppm. In addition, when nitrogen substitution etc. are performed after adding a monomer to a solvent, it is preferable that the dissolved oxygen concentration of the system also containing a monomer is within the said range.

Adjustment of the dissolved oxygen concentration in the above solvent may be performed in a polymerization reaction tank, or a solution in which the amount of dissolved oxygen has been adjusted in advance may be used. Methods for expelling oxygen in the solvent include the following (1) to ( Method 5) is preferred.
(1) After filling an airtight container containing a solvent with an inert gas such as nitrogen under pressure, the pressure inside the airtight container is lowered to lower the partial pressure of oxygen in the solvent. The pressure inside the closed container may be reduced under a nitrogen stream.
(2) While the gas phase in the container containing the solvent is replaced with an inert gas such as nitrogen, the liquid phase is stirred for a long time.
(3) Bubbling an inert gas such as nitrogen into the solvent placed in the container for a long time.
(4) Once the solvent is boiled, it is cooled under an inert gas atmosphere such as nitrogen.
(5) A static mixer is installed in the middle of the pipe, and an inert gas such as nitrogen is mixed in the pipe that transfers the solvent to the polymerization reaction tank.

Each of the polymers obtained as described above can be used as is by being blended into a cement admixture, but if necessary, the polymers may be further neutralized with an alkaline substance before use. Suitable alkaline substances include inorganic salts such as hydroxides and carbonates of monovalent or divalent metals; ammonia; and organic amines. Further, after the reaction is completed, the concentration can be adjusted if necessary. In addition, after performing a copolymerization reaction using the corresponding unsaturated carboxylic acid ester monomer without using the unsaturated carboxylic acid monomer (general formula (II)) as a monomer component, the pH By adjusting the structure of the unsaturated carboxylic acid monomer (for example, the general formula ( II)) can also be incorporated into the polymer.

[Cement admixture]
The cement admixture of the present invention has excellent water-reducing performance by containing the polymer of the present invention. Furthermore, if necessary, a non-polymerizable (poly)alkylene glycol having no alkenyl group may be contained, and the polymer of the present invention may be neutralized with an alkaline substance and used as a polymer salt. Preferred examples of such alkaline substances include inorganic substances such as monovalent metal and divalent metal hydroxides, chlorides, and carbon salts; ammonia; and organic amines.

Furthermore, when the polymer of the present invention is used as a cement admixture, the weight average molecular weight (Mw) of the polymer is 500 to 500,000 in terms of polystyrene measured by gel permeation chromatography (hereinafter referred to as "GPC"); In particular, it is preferably in the range of 5,000 to 300,000. If the weight average molecular weight is less than 500, the water reduction performance as a cement admixture will deteriorate, which is not preferable. On the other hand, if the weight average molecular weight exceeds 500,000, it is not preferable because the water reduction performance and slump loss prevention ability as a cement admixture decrease.

Moreover, the polymer of the present invention can be used as a cement admixture as it is alone or as a mixture of two or more. Furthermore, the polymer of the present invention can be used as a main component in combination with other known cement admixtures. Such known cement admixtures include, for example, conventional cement dispersants, air entraining agents, cement wetting agents, swelling agents, waterproofing agents, retarders, rapid setting agents, water-soluble polymeric substances, thickeners, flocculants, etc. agents, drying shrinkage reducers, strength enhancers, curing accelerators, antifoaming agents, etc.

In addition, when using a known cement dispersant, the blending mass ratio of the polymer (salt) of the present invention and the known cement dispersant is 1/99 to 1/99, respectively, as a weight ratio (weight %) in terms of solid content. 99/1 is preferred, 5/95 to 95/5 is more preferred, and 10/90 to 90/10 is even more preferred.

Known cement dispersants used in combination with the above include, for example, polyalkylaryl sulfonate salts such as naphthalene sulfonic acid formaldehyde condensate; melamine formalin resin sulfonate salts such as melamine sulfonic acid formaldehyde condensate; aminoarylsulfonic acid- Aromatic aminosulfonate salts such as phenol-formaldehyde condensates; Lignosulfonate salts such as ligninsulfonates and modified ligninsulfonates; Various sulfones with sulfonic acid groups in the molecule such as polystyrene sulfonate salts Examples include cement dispersants such as acid-based dispersants.

Further, as the antifoaming agent, known antifoaming agents such as those exemplified in (1) and (2) below are suitable.
(1) Oxyalkylene antifoaming agents: Polyoxyalkylenes such as (poly)oxyethylene (poly)oxypropylene adducts; Polyoxyalkylene alkyl ethers such as diethylene glycol heptyl ether; Polyoxyalkylene acetylene ethers; ) Oxyalkylene fatty acid esters; Polyoxyalkylene sorbitan fatty acid esters; Polyoxyalkylene alkyl (aryl) ether sulfate ester salts; Polyoxyalkylene alkyl phosphate esters; Polyoxypropylene polyoxyethylene laurylamine (propylene oxide 1-20 amines derived from fatty acids obtained from cured beef tallow to which alkylene oxide has been added (1-20 mole adducts of propylene oxide, 1-20 mole adducts of ethylene oxide, etc.) Alkylenealkylamines; polyoxyalkyleneamide, etc.
(2) Antifoaming agents other than oxyalkylene-based defoaming agents: Mineral oil-based, oil-based, fatty acid-based, fatty acid ester-based, alcohol-based, amide-based, phosphoric ester-based, metal soap-based, silicone-based, etc. antifoaming agents.

The cement admixture according to the present invention can be used in hydraulic cements such as portland cement, high belite content cement, alumina cement, various mixed cements, or hydraulic materials other than cement such as gypsum.

The cement admixture of the present invention can be used for various hydraulic materials, ie, cement and hydraulic materials other than cement, such as gypsum. As a hydraulic composition containing a hydraulic material, water, and the cement admixture of the present invention, and further containing fine aggregate (sand, etc.) or coarse aggregate (crushed stone, etc.) as necessary, a cement paste is used. , mortar, concrete and plaster are suitable.

[Cement composition]
Among the above hydraulic compositions, cement compositions using cement as the hydraulic material are most common, and such cement compositions contain the cement admixture of the present invention, cement, and water as essential components. It turns out. Such cement compositions are also part of the invention.

Cement used in the cement composition of the present invention includes portland cement (normal, early strength, ultra early strength, moderate heat, sulfate resistant and low alkali forms of each), various mixed cements (blast furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, super fast hardening cement (1 clinker fast hardening cement, 2 clinker fast hardening cement, magnesium phosphate cement), grouting cement, oil well cement, low heat generation cement (low heat generation blast furnace cement) , fly ash mixed low heat generation blast furnace cement, high Blite content cement), ultra-high strength cement, cement solidifying agent, ecocement (cement manufactured using one or more types of municipal waste incineration ash and sewage sludge incineration ash) is suitable, and further fine powders such as blast furnace slag, fly ash, cinder ash, clinker ash, hasquash, silica fume, silica powder, limestone powder, and gypsum may be added. In addition to aggregates such as gravel, crushed stone, granulated slag, and recycled aggregate, we also use silica, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromatic, and magnesia. Refractory aggregates such as

In the cement composition of the present invention, the unit water amount per 1 m ³ , the total usage amount of cement, fly ash and slag (hereinafter also referred to as "B"), and the water/B ratio are as follows: It is preferable that the unit water amount is 100 to 185 kg/m ³ , the B amount used is 250 to 800 kg/m ³ , and the water/B ratio (mass ratio) is 0.1 to 0.7, and more preferably, the unit water amount is 120 to 175 kg. /m ³ , amount of B used is 270 to 800 kg/m ³ , water/B ratio (mass ratio) = 0.2 to 0.65, and can be used widely from poor to rich combinations, and has a large amount of unit B. It is effective for both high-strength concrete and poorly mixed concrete with a unit B content of 300 kg/m ³ or less.

The blending ratio of the cement admixture of the present invention in the cement composition of the present invention is, for example, when used in mortar or concrete using hydraulic cement, the ratio is 0 to the total mass of cement, fly ash, and slag. The content is preferably .01 to 5.0%. This addition brings about various favorable effects such as a reduction in the unit water amount, an increase in strength, and an improvement in durability. If the above-mentioned blending ratio is less than 0.01%, there is a risk that the performance will be insufficient.On the other hand, even if a large amount exceeding 5.0% is used, the effect will virtually reach a ceiling and it will be disadvantageous from an economical point of view. There is a risk that More preferably, it is 0.02% or more and 2.0% or less, and even more preferably 0.05% or more and 1.0% or less, and the amount added in such a ratio is do it. Further, the preferred range of blending ratio is more preferably 0.02 to 2.0%, and even more preferably 0.05 to 1.0%.

The cement admixture of the present invention can be used in combination with those used as conventional cement dispersants, and can also be used in combination with a plurality of cement dispersants. In addition, when using a conventional cement dispersant, the blending mass ratio of the cement admixture of the present invention and the cement dispersant cannot be uniquely determined due to differences in the type, composition, test conditions, etc. of the cement dispersant. No, but preferably 1 to 99/99 to 1, more preferably 5 to 95/95 to 5, and even more preferably 10 to 90/90 to 10.

[concrete]
The cement composition of the present invention is also effective for ready-mix concrete, concrete for secondary concrete products (precast concrete), centrifugally formed concrete, vibration compacted concrete, steam-cured concrete, shotcrete, etc. High fluidity is required for fluid concrete (concrete with a slump value of 22 to 25 cm), high fluid concrete (concrete with a slump value of 25 cm or more and a slump flow value of 50 to 70 cm), self-compacting concrete, self-leveling materials, etc. It is also effective for mortar and concrete.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

Various materials used in production examples, examples, and comparative examples are shown below.
-2-(1-methylethenyl)-1,3-propanediol: purity 91%, J. A.M. CHEM. Soc., 104, 555 (1984).
-3-methylene-1,5-pentanediol: purity 95%, it can be produced by the production method described in International Publication No. 2018/143104.
・3-Methyl-3-buten-1-ol: Manufactured by Kuraray Co., Ltd., purity 98%
・Ethylene oxide: Manufactured by Nippon Shokubai Co., Ltd. ・Sodium hydroxide: Manufactured by Wako Pure Chemical Industries, Ltd. ・Hydrogen peroxide aqueous solution: Manufactured by Wako Pure Chemical Industries, Ltd. ・Acrylic acid: Manufactured by Wako Pure Chemical Industries, Ltd. ・L-Ascorbic acid: Manufactured by Wako Pure Chemical Industries, Ltd. 3-Mercaptopropionic acid manufactured by Tokyo Chemical Industry Co., Ltd.

In each example, ¹ H-NMR, GPC, and HPLC analyzes were conducted under the following conditions.
[GPC analysis conditions]
Analytical equipment: GPC-8020 (manufactured by Tosoh Corporation)
Detector: RI-8020 (manufactured by Tosoh Corporation)
Column used: Shodex GPC KF-802, KF-802.5, KF-803L, KF-G (guard column) (manufactured by Showa Denko K.K.)
Analysis conditions Developing solution: THF
Flow rate: 0.9mL/min
Column temperature: 40℃
Sample injection volume: 30μL
Analysis: GPC-model II (manufactured by Tosoh Corporation)
[ ¹ H-NMR analysis]
Analytical equipment: ULTRA SHIELD 400 PLUS (manufactured by Bruker)
Solvent: Deuterated chloroform At room temperature, cumulative number of times: 120 Number of oxyalkylene groups added:
Among the monomers produced, the molar ratio is determined from the integral ratio of each component derived from the unsaturated alcohol and the oxyalkylene group, and the number of oxyalkylenes added is calculated by converting to a mass ratio based on the molecular weight of each component. I asked for
[HPLC analysis]
Analytical instrument: Nexera X2 (manufactured by Shimadzu Corporation)
Column used: Mightysil RP-18 (length 250 mm, inner diameter 4.6 mm, particle size 5 μm) (manufactured by Kanto Kagaku Co., Ltd.)
Detector: SPD-M30A (manufactured by Shimadzu Corporation)
Developing solution: A mixed solution of 600 g of water, 400 g of methanol, and 0.8 g of phosphoric acid Analysis conditions: Flow rate of 1.0 mL/min
Column temperature: 40℃
Sample injection volume: 100μL

[Production Example 1] (IA)
30 g of unsaturated alcohol (2-(1-methylethenyl)-1,3-propanediol) and 0.5 g of sodium hydroxide as a catalyst were placed in a SUS high-pressure reactor equipped with a thermometer, a stirrer, and a nitrogen and ethylene oxide inlet tube. was charged, the inside of the reaction vessel was replaced with nitrogen under stirring, and the internal temperature was raised to 100°C. Thereafter, 910 g of ethylene oxide was introduced into the reactor over 6 hours while maintaining the temperature at 100°C, and after heating and stirring for 2 hours, the reaction was completed and the monomer represented by the following formula (IA) I got a body. ¹ H-NMR measurement results are shown below.

¹ H NMR (400 MHz, CDCl ₃ ) δ 1.8 ppm (CH ₂ =C( CH ₃ )-), 2.6 ppm (CH ₂ =C(CH ₃ )C H -), 3.5-3.9 ppm ( oxyalkylene group), 4.8-4.9 ppm (C H ₂ =C(CH ₃ )-). If we take the integral ratio at the positions of 3.5 to 3.9 ppm and 4.8 to 4.9 ppm, we get 312. Since the oxyalkylene group has 4 protons and 2 OH chains, an average of 80 moles of ethylene oxide was added to the raw unsaturated alcohol.

[Production Example 2] (III-A)
30 g of 3-methylene-1,5-pentanediol was used instead of 2-(1-methylethenyl)-1,3-propanediol as the unsaturated alcohol, 0.3 g of sodium hydroxide was used as the catalyst, A monomer represented by (III-A) below was obtained in the same manner as in Production Example 1, except that the amount of ethylene oxide used was changed to 600 g.

¹ H NMR (400 MHz, CDCl ₃ ) δ 2.4 ppm (CH ₂ =C(C H ₂ -) ₂ -), 3.5-3.9 ppm (oxyalkylene group), 4.8 ppm (C H ₂ =C( _CH2 ) _2- ). Taking the integral ratio at the positions of 3.5 to 3.9 ppm and 4.8 ppm gives 209. Since the oxyalkylene group has four protons and two OH chains, an average of 50 moles of ethylene oxide was added to one molecule of unsaturated alcohol as a raw material.

[Manufacture example 3]
The following (IV-A ) was obtained.

¹ H NMR (400 MHz, CDCl ₃ ) δ 1.8 ppm (CH ₂ =C( CH ₃ )-), 2.4 ppm (CH ₂ =C(CH ₃ )C H ₂ -), 3.5-3.9 ppm (oxyalkylene group), 4.7-4.8 ppm (C H ₂ =C(CH ₂ ) ₂ -). If we take the integral ratio at the positions of 3.5 to 3.9 ppm and 4.7 to 4.8 ppm, we get 202. Since the oxyalkylene group has 4 protons and 1 OH chain, based on the integral ratio of these, an average of 50 moles of ethylene oxide was added to the raw material unsaturated alcohol.

The properties and water solubility of the monomers obtained in Production Examples 1 to 3 at 25°C and 50°C were evaluated. The results are shown in Table 1.

From Table 1, the monomer obtained in Production Example 1 or Production Example 2 has a higher solubility in water at 25°C than the monomer obtained in Production Example 3, and at 50°C it dissolves in water at any rate. It can be seen that it mixes with water. From this result, the polymer using the monomer of Production Example 1 or Production Example 2 has better solubility in water than the conventionally used polymer using the monomer of Production Example 3. can be easily inferred. Therefore, by using these polymers with excellent water solubility as cement admixtures, the amount of water used when making cement admixtures can be reduced, and cement compositions using these cement admixtures have a high volumetric efficiency. It is suggested that the performance is excellent and the productivity is high.

Subsequently, a polymer was produced using the monomer obtained with reference to Production Example 1, Production Example 2, and Production Example 3, and the obtained polymer was evaluated as a cement admixture. In addition, in order to equalize the conditions, the amount of ion-exchanged water in each example was the same.

[Example 1]
A glass reaction vessel equipped with a thermometer, a stirrer, a dropping funnel, a nitrogen introduction tube, and a reflux condenser was purged with nitrogen, and 29.3 g of ion-exchanged water and 98.7 g of the monomer obtained in Production Example 1 were charged. Raise the temperature to 60°C. 4.8 g of a 4% aqueous hydrogen peroxide solution was added thereto. Next, an aqueous solution prepared by diluting 8.2 g of acrylic acid with 1.6 g of ion-exchanged water was added dropwise over 4 hours. At the same time, an aqueous solution of 0.12 g of L-ascorbic acid and 0.12 g of 3-mercaptopropionic acid dissolved in 31.8 g of ion-exchanged water was added dropwise over 4.5 hours. After the dropwise addition was completed, stirring was continued for 1 hour to complete the polymerization reaction. Thereafter, the reaction solution was neutralized to pH 6.5 using a 30% aqueous sodium hydroxide solution at a temperature below the polymerization reaction temperature to obtain an aqueous solution of a polycarboxylic acid copolymer with a weight average molecular weight (Mw) of 30,000. Ta. According to HPLC analysis, the monomer conversion rate at this time was 47%, and the acrylic acid conversion rate was 99.9% or more. The obtained aqueous solution was adjusted by adding dilution water so that the active ingredient concentration was 10.0%.
Here, the above active ingredient concentration is calculated by multiplying the solid content by the active ingredient ratio calculated using the reaction rate of the unsaturated carboxylic acid monomer, which is a polymerizable monomer, and the monomer of the production example. It is a value defined by the following formula. The amounts of monomers used below are the amounts of each monomer used during polymerization. Moreover, the solid content is obtained by distilling off the aqueous solution of the polycarboxylic acid copolymer obtained in the example under reduced pressure and drying it.
Active ingredient concentration = [(a+b)/(A+B)]×NV
The abbreviations in the above formula are as follows.
A: Amount of unsaturated carboxylic acid monomer used B: Amount of monomer used in production example a: Amount of unsaturated carboxylic acid monomer used × conversion rate b: Use of monomer in production example Amount x conversion rate NV: solid content

[Example 2]
Instead of 98.7 g of the monomer obtained in Production Example 1, a monomer with an average of 100 moles of ethylene oxide added to 1 mole of 2-(1-methylethenyl)-1,3-propanediol (i.e., A polycarboxylic acid-based product having a weight average molecular weight (Mw) of 26,700 was prepared in the same manner as in Example 1, except that 98.7 g of a monomer (containing twice the amount of ethylene oxide) was used as compared to the monomer in Example 2. An aqueous solution of the copolymer was obtained. According to HPLC analysis, the monomer conversion rate at this time was 49%, and the acrylic acid conversion rate was 99.9% or more. The obtained aqueous solution was adjusted by adding dilution water so that the active ingredient concentration was 10.0%.

[Comparative example 1]
A weight average molecular weight (Mw) of 25500 was prepared in the same manner as in Example 1, except that 98.7 g of the monomer obtained in Production Example 3 was used instead of 98.7 g of the monomer obtained in Production Example 1. An aqueous solution of a polycarboxylic acid copolymer was obtained. According to HPLC analysis, the monomer conversion rate at this time was 58%, and the acrylic acid conversion rate was 99.9% or more. The obtained aqueous solution was adjusted by adding dilution water so that the active ingredient concentration was 10.0%.

Next, a cement admixture (Ad) was prepared using the aqueous solutions of the copolymers produced in Example 1, Example 2, and Comparative Example 1, and the physical properties of cement using this cement admixture were measured. .

As the cement (C), ordinary Portland cement manufactured by Taiheiyo Cement Co., Ltd. (density: 3.16 g/cm ³ ) was used. As the fine aggregate (S), land sand from the Oigawa River in Shizuoka Prefecture (surface dry density: 2.66 g/cm ³ ) was used. As the coarse aggregate (G), crushed sandstone 2005 from Ome City, Tokyo (surface dry density 2.66 g/cm ³ ) was used. As the kneading water (W), tap water of Chigasaki City, Kanagawa Prefecture was used. The aggregate used in the test was adjusted so that the surface water content of the fine aggregate was 1% or less, and the surface water content of the coarse aggregate was dry and saturated. All the materials used were stored in a constant temperature and humidity room at 20° C., and were taken out immediately before use. The slump flow was determined according to JIS A 1150:2014 "Slump flow test method for concrete". Slump was determined according to JIS A 1101:2014 "Slump test method for concrete".
The concrete was mixed using a forced mixing mixer pan with a capacity of 55 L according to the procedure shown below. The amount of concrete mixed was 30L.
Fine aggregate (half amount), cement, and fine aggregate (half amount) are added, and after 10 seconds, air kneading is performed, and water and an admixture are added. The mixture was kneaded for 30 seconds, scraped off, coarse aggregate was added, and kneaded for another 90 seconds, then discharged and measured.

The mixing ratio of concrete is shown below.

The retention rate, defined as the value obtained by dividing the flow value after 60 minutes by the initial flow value at 0 minutes, was used as an index, and the retention was evaluated based on the following evaluation criteria. The higher the retention value, the better the retention.
Retention evaluation criteria Evaluation A: Retention rate is 50% or more Evaluation X: Retention rate is 25% or more and less than 50%

It can be seen that Examples 3 and 4 exhibit higher flow retention rates than Comparative Example 2, which is a conventional cement admixture.

Claims (7)

A polymer containing a structural unit derived from general formula (II) and a structural unit derived from general formula (III) below.
[In general formula (II), R ⁵ , R ⁶ and R ⁷ each independently represent a hydrogen atom or a methyl group, and M is a group consisting of a hydrogen atom, a monovalent metal atom, a divalent metal atom, and ammonium represents at least one selected from ]
[In general formula (III), R ⁸ and R ⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R _b and R _c each independently represent an alkylene group having 2 to 18 carbon atoms. represents. l represents any integer from 0 to 4, and m represents any integer from 1 to 200. ] The polymer according to claim 1, wherein in general formula (II), M is at least one selected from the group consisting of a hydrogen atom, a monovalent metal atom, and a divalent metal atom. The polymer according to claim 1 or 2, wherein in general formula (III), R ⁸ and R ⁹ are hydrogen atoms, R _b and R _c are ethylene groups, and l is 2. A cement admixture comprising the polymer according to any one of claims 1 to 3. A cement composition comprising the cement admixture according to claim 4. Concrete obtained by curing the cement composition according to claim 5. A compound represented by the following general formula (V).
[In the general formula (V), R _b and R _c each independently represent an alkylene group having 2 to 18 carbon atoms. l represents any integer from 0 to 4, and m represents any integer from 1 to 200. ]