JP2023117034A - Hydraulic composition, cured product, and manufacturing method of hydraulic composition - Google Patents

Abstract

To provide a hydraulic composition capable of obtaining a cured product having sufficient strength and low water absorptivity.SOLUTION: A hydraulic composition formed by mixing (A) cement with (B) a hydraulic dispersion of a urethane resin, wherein the (B) component is a urethane resin formed by a polymerization reaction of at least one (C) polyhydric alcohol and at least one (D) polyisocyanate, and a solid component amount of (B) satisfies at least one of the following conditions (1) and (2) below: (1) the solid component amount is 25 pts.mass or less based on 100 pts.mass of (A) component; and (2) the solid component amount is 7 mass% or less based on 100 mass% of the total amount of hydraulic composition.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a hydraulic composition, a cured product, and a method for producing a hydraulic composition.

Conventionally, the surface of building and civil engineering structures made of concrete is coated with polymer cement or mortar containing siliceous waterproofing agents for the purpose of preventing deterioration of the building structure due to water intrusion and water leakage into the interior. Injection/permeation/film coating methods using organic resin, cement, and water glass materials have been proposed.

For example, in the technique described in Patent Document 1, an adhesive such as a urethane-based resin is thinly applied on a resin-coated waterproof layer (urethane-based waterproof layer) containing a urethane-based resin, and EVA (ethylene vinyl acetate) is applied. Polymer) type thermoplastic resin sheet is spread all over. A floor slab waterproof structure using a urethane-based waterproof layer is constructed by sequentially laminating a primer resin layer, a urethane-based waterproof layer, a urethane resin adhesive layer, and an EVA-based thermoplastic resin sheet. After forming the primer resin layer and urethane-based waterproof layer, the floor slab waterproof structure with such a configuration mixes the main agent/curing agent (isocyanate/polyol) of the urethane resin adhesive at the construction site, and then applies it with a roller brush or the like. Apply thinly and evenly with a thermoplastic resin sheet and spread it evenly.

Japanese Patent No. 3956757

However, cement-based hardened bodies obtained by hardening conventional polymer cement or the like do not have sufficient strength and have high water absorbency, so there is a problem that they are easily deteriorated due to fatigue in water.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a hydraulic composition capable of obtaining a cured product having sufficient strength and low water absorption. Another object of the present invention is to provide a cured product of such a hydraulic composition and a method for producing the hydraulic composition.

The hydraulic composition of the present invention comprises (A) cement blended with (B) an aqueous dispersion of urethane resin, and component (B) comprises at least one (C) polyhydric alcohol and at least one (D) A hydraulic composition which is formed by a polymerization reaction of a polyvalent isocyanate and in which the solid content of (B) satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition; The aqueous dispersion of the hydraulic composition may contain a surfactant.

The hydraulic composition of the present invention comprises (A) cement, (B) a urethane resin, and (E) a surfactant, and component (B) comprises at least one (C) polyhydric alcohol and at least one (D) is formed by the polymerization reaction of the polyvalent isocyanate, and the solid content of (B) satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7 % by mass or less with respect to 100% by mass of the total amount of the hydraulic composition;

The component (C) may contain (C1) an ethylene oxide adduct or a propylene oxide adduct of a dihydric alcohol.

The component (C1) may be an ethylene oxide adduct of polypropylene oxide.

The component (C) may contain (C2) a short-chain dihydric alcohol having a molecular weight of 200 or less.

The component (C) may contain (C3) a trihydric or higher alcohol.

The hydraulic composition may further contain aggregate.

The cured product of the present invention is a cured product of the hydraulic composition.

The method for producing the hydraulic composition of the present invention comprises a step of dispersing in water a urethane resin formed by a polymerization reaction of a polyhydric alcohol and a polyisocyanate to obtain an aqueous dispersion, and mixing the cement and the aqueous dispersion. and obtaining a hydraulic composition, wherein the solid component amount of the urethane resin in the hydraulic composition satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition;

ADVANTAGE OF THE INVENTION According to this invention, the hydraulic composition which has sufficient intensity|strength and can obtain the hardened|cured material which has low water absorption can be provided. Further, according to the present invention, it is possible to provide a cured product of such a hydraulic composition and a method for producing the hydraulic composition.

The hydraulic composition of the present embodiment is obtained by blending (A) cement with (B) an aqueous dispersion of urethane resin, and component (B) comprises at least one (C) polyhydric alcohol and at least one (D) is formed by the polymerization reaction of the polyvalent isocyanate, and the solid content of (B) satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition;

In addition, the hydraulic composition of the present embodiment contains (A) cement, (B) a urethane resin, and (E) a surfactant,
The (B) component is formed by a polymerization reaction of at least one (C) polyhydric alcohol and at least one (D) polyhydric isocyanate,
The content of (B) may satisfy at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition;

According to the hydraulic composition of the present embodiment, a cured product having sufficient strength and low water absorption can be obtained.

Regarding condition (1), the content of component (B) (amount of solid component) is preferably 25 parts by mass or less, more preferably 23 parts by mass or less, and 20 parts by mass or less per 100 parts by mass of component (A). It is more preferable in it being below a mass part. The total amount of component (B) is not particularly limited as long as it is not 0 parts by mass because the above effect can be obtained even if it is very small, but it should be 0.01 part by mass or more per 100 parts by mass of component (A). may be 0.05 parts by mass or more, may be 0.1 parts by mass or more, or may be 1 part by mass or more.

The hydraulic composition in condition (2) may contain the above components (A) and (B), an aggregate, and added water. Regarding the condition (1), the total amount of the solid components (solid component amount) of (B) may be 7% by mass or less, or 6% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition. The total amount of the component (B) is not particularly limited as long as it is not 0% by mass because the above effect is exhibited even if it is very small, but it is 0.01% by mass or more with respect to the total amount of 100% by mass of the hydraulic composition. may be 0.05% by mass or more, and may be 0.1% by mass or more.

[cement]
The hydraulic composition contains cement as the (A) component. Cement is not particularly limited, and Portland cement such as ordinary Portland cement, high-early-strength Portland cement, ultra-early-strength Portland cement, moderate-heat Portland cement, low-heat Portland cement, sulfate-resistant Portland cement; blast-furnace cement, fly ash cement, silica fume Mixed cement such as cement; and other cements such as eco-cement, ultra-rapid hardening cement, alumina cement, phosphate cement, air-hardening cement, and the like.

[Polyhydric alcohol]
The hydraulic composition may contain a polyhydric alcohol as the (C) component. The component (C) may be contained in the aqueous dispersion, or may be added to the hydraulic composition separately from the aqueous dispersion. Polyhydric alcohols are compounds having two or more alcoholic hydroxyl groups in the molecule. Component (C) is not particularly limited as long as it is a compound having multiple hydroxyl groups in the molecule, and includes aliphatic polyhydric alcohols (hydrocarbon compounds in which multiple hydrogen atoms are substituted with hydroxyl groups), polyether polyols, and polyesters. Examples include polyols, castor oil or derivatives thereof, polybutadiene-based polyols, alkanolamines, and the like. The number of hydroxyl groups contained in one molecule of the polyhydric alcohol may be 2 to 6, 2 to 5, 2 to 3, or 2. The number of hydroxyl groups may be an average value (number average) per molecule, in which case the number may be a rational number. Component (C) may be an unreacted product during the production of component (B), or may be added separately from component (B).

The polyhydric alcohol preferably contains at least one compound selected from (C1) to (C3) below.
(C1) Ethylene oxide adduct or propylene oxide adduct of dihydric alcohol.
(C2) A dihydric alcohol having a molecular weight of 200 or less (hereinafter also referred to as a short-chain dihydric alcohol).
(C3) Ethylene oxide adducts or propylene oxide adducts of trihydric or higher alcohols.

Component (C1) is a compound having a structure obtained by a ring-opening addition reaction of ethylene oxide or propylene oxide using a dihydric alcohol as an initiator, and having the same structure as the structure obtained by the ring-opening addition reaction. As long as it is a compound, it may not be actually produced by ring-opening addition of ethylene oxide or propylene oxide.

The number average molecular weight of component (C1) is preferably from 300 to 3,000, more preferably from 400 to 2,500, and even more preferably from 500 to 2,000, from the viewpoint of water dispersibility of the solid component of component (B).

Dihydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,6-hexanediol. hydrocarbon compounds substituted with hydroxyl groups), polypropylene glycol (poly(1,2-propylene glycol) or polypropylene oxide), polyalkylene glycol which is a dihydric alcohol such as polyethylene glycol. Only one kind of dihydric alcohol may be used, or two or more kinds thereof may be used in combination.

As the component (C1), an ethylene oxide adduct of polypropylene glycol is preferable from the viewpoint of imparting hydrophilicity to the urethane resin described later. The mass ratio of ethylene oxide units to propylene oxide units (EO/PO mass ratio) in such an adduct is preferably 10/90 to 90/10, more preferably 15/85 to 80/20.

As the (C1) component, Actcole ED28 (manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.; number average molecular weight 4000, EO/PO mass ratio: 20/80), Actcole ED36 (manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.; number average molecular weight 3600, EO/PO mass ratio: 78/22), Actcol ED56 (manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.; number average molecular weight: 2000).

The molecular weight of component (C2) may be 180 or less, or 150 or less. Specific examples of component (C2) include aliphatic dihydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol and 1,6-hexanediol, and dialkylene glycols such as diethylene glycol and dipropylene glycol. .

Component (C3) is a compound having a structure obtained by carrying out a ring-opening addition reaction of ethylene oxide or propylene oxide using a trihydric or higher alcohol as an initiator, and has the same structure as the structure obtained by the ring-opening addition reaction. may not be actually produced by ring-opening addition of ethylene oxide or propylene oxide, as long as it is a compound. It has the effect of lowering the water solubility of the urethane resin described later.

Examples of trihydric or higher alcohols include trihydric alcohols such as glycerin and trimethylolpropane, and trihydric or higher alcohols such as pentaerythritol, dipentaerythritol, sorbitol, and monosaccharides or polysaccharides (eg, sucrose). Among them, trihydric alcohol is preferred, and glycerin is more preferred. Only one type of trihydric alcohol may be used, or two or more types may be used in combination.

The number average molecular weight (Mn) of the component (C3) is preferably 300 to 7000, more preferably 500 to 6500, and further preferably 1000 to 6000, from the viewpoint of reducing the water absorption of the cured product formed from the hydraulic composition. 2000 to 6000 are particularly preferred.

As the (C3) component, for example, EXCENOL 430 (Mn = 430), EXCENOL 1030 (Mn = 1000), EXCENOL 3030 (Mn = 3000), EXCENOL 4030 (Mn = 4000), EXCENOL 5030 (Mn = 5100) (any (manufactured by AGC Co., Ltd.).

[Polyvalent isocyanate]
The hydraulic composition may contain a polyisocyanate as component (D). The component (D) may be contained in the aqueous dispersion, or may be added to the hydraulic composition separately from the aqueous dispersion. (D) Polyvalent isocyanate is not particularly limited as long as it has two or more isocyanate groups in the molecule. Specifically, component (D) includes phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1-methyl -3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4 ,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4 -diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2, 6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-diisocyanate, biphenyl-4,4'-diisocyanate, 3-3'-dimethylbiphenyl aromatic polyisocyanates such as -4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, diphenylmethane-2,4-diisocyanate; tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di(isocyanatomethyl)cyclohexane, 1,4-di (Isocyanatomethyl)cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 2,4′-dicyclohexylmethane diisocyanate, 2,2′-dicyclohexylmethane diisocyanate, 3,3′-dimethyl-4,4′ - aliphatic or cycloaliphatic polyisocyanates such as dicyclohexylmethane diisocyanate, carbodiimide-modified isocyanates, polymethylene polyphenyl polyisocyanates, and the like. These polyvalent isocyanates may be used alone or in combination of two or more. Among these, from the viewpoint of mechanical strength and adhesiveness, aromatic polyisocyanates are preferred, aromatic diisocyanates are more preferred, and toluene diisocyanate (1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6- Phenylene diisocyanate and 1-methyl-2,5-phenylene diisocyanate) are more preferred. Component (D) may be an unreacted product during the production of component (B), or may be added separately from component (B). The polyvalent isocyanate compound may not be contained in the hydraulic composition, and its content may be 25 parts by mass or less, or 10 parts by mass or less, relative to 100 parts by mass of component (B). Well, it may be 5 parts by mass.

[Urethane resin]
A hydraulic composition contains a urethane resin as a (B) component. The urethane resin may be blended into the hydraulic composition as an aqueous dispersion. The urethane resin is a polymerization reaction product formed when a polymerization reaction (sequential polymerization) is performed between a hydroxyl group of a polyhydric alcohol and an isocyanate group of a polyhydric isocyanate, and the residue of the polyhydric alcohol and the and residues of polyvalent isocyanates. Component (B) contains a polyurethane compound having two or more urethane bonds in the molecule, and may optionally contain a monourethane compound having one urethane bond in the molecule.

Such a urethane resin may be contained in, for example, a partially polymerized product obtained by heating a mixture of a polyhydric alcohol and a polyhydric isocyanate as raw materials. In the partial polymer, not all of the polyhydric alcohol and polyvalent isocyanate contained in the mixture are completely reacted, and in addition to the urethane resin, the partial polymer contains the polyhydric alcohol or polyhydric A portion of the isocyanate remains unreacted.

Regarding the (B) urethane resin contained in the aqueous dispersion, the total molar amount ([OH]) of the hydroxyl groups possessed by the (C) polyhydric alcohol before the reaction (that is, the hydroxyl groups possessed by the polyhydric alcohol used as the starting material). ) and (D) the total molar amount (expressed as [NCO]) of the isocyanate groups before the reaction of the polyvalent isocyanate (that is, the isocyanate groups possessed by the polyvalent isocyanate as a raw material) [NCO]/[OH ] is preferably greater than 1, more preferably 1.5 or more. When [NCO]/[OH] is greater than 1, there are many unreacted isocyanate groups in the hydraulic composition, so that many reactions between the isocyanate groups and water or polyhydric alcohol can be used as the cement hardens. Therefore, it is preferable.

Component (B) preferably contains at least one residue of the above components (C1), (C2) and (C3), and contains any residue of the above components (C1), (C2) and (C3) and more preferred. The content of component (C1) in the raw material of component (B) is preferably 20 to 70% by mass, more preferably 30 to 60% by mass, with respect to 100% by mass of the total polyhydric alcohol used. . The content of component (C2) in the raw material of component (B) is preferably 1 to 15% by mass, more preferably 3 to 10% by mass, relative to 100% by mass of the total polyhydric alcohol used. . The content of component (C3) in the raw material of component (B) is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, relative to 100% by mass of the total polyhydric alcohol used. .

An aqueous dispersion is a dispersion obtained by dispersing the component (B) in water. That is, the aqueous dispersion contains water (or an aqueous solution) as a continuous phase and particles containing a urethane resin. The component (B) may be dispersed substantially uniformly in the aqueous dispersion. The aqueous dispersion may contain a surfactant. The aqueous dispersion may contain at least one of the (C) component and the (D) component in addition to the (B) component. The components (C) and (D) may be unreacted products during production of the urethane resin, or may be added separately to the aqueous dispersion.

[water]
Water contained in the aqueous dispersion is not particularly limited, and may be, for example, tap water, distilled water, deionized water, or the like. The content of water in the hydraulic composition is preferably 20 to 100 parts by mass, more preferably 25 to 80 parts by mass, and still more preferably 30 to 70 parts by mass based on 100 parts by mass of cement. The content of water in the aqueous dispersion is preferably 75 to 98 parts by mass, more preferably 85 to 95 parts by mass, per 100 parts by mass of the aqueous dispersion.

Surfactants include, for example, sodium lauryl sulfate. The surfactant plays a role of stably dispersing the urethane resin in water. The content of the surfactant in the dispersion is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the dispersion. In addition, known surfactants can be used. Examples of anionic surfactants include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, and sodium polyoxyethylene alkylphenyl ether sulfate. Examples include polyoxyethylene alkyl ethers and polyoxyethylene alkylphenyl ethers, and examples of cationic surfactants include alkylammonium salts.

[aggregate]
The aggregate is not particularly limited, and may be fine aggregate, coarse aggregate, or the like. The fine aggregate is not particularly limited, and may be silica sand, river sand, sea sand, mountain sand, crushed sand, hard blast furnace slag fine aggregate, blast furnace slag fine aggregate, copper slag fine aggregate, electric arc furnace oxidizing slag fine aggregate, or the like. you can The coarse aggregate is not particularly limited, and may be gravel, crushed stone, blast furnace slag coarse aggregate, electric furnace oxidation slag coarse aggregate, or the like. The hydraulic composition may contain at least one of fine aggregate and coarse aggregate. Moreover, the hydraulic composition may contain two or more kinds of fine aggregates, and may contain two or more kinds of coarse aggregates. In addition, as defined in JIS A 0203: 2014 "concrete terminology", fine aggregate is an aggregate that passes through a 10 mm mesh sieve and 85% or more by mass of a 5 mm mesh sieve, and coarse aggregate is It is an aggregate that retains 85% or more by mass in a 5 mm mesh sieve.

When the aggregate contains only fine aggregate, the content of the aggregate in the hydraulic composition is preferably 50 to 500 parts by mass, more preferably 100 to 400 parts by mass, more preferably 100 to 400 parts by mass, more preferably 150 to 350 parts by mass.

[Other ingredients]
The hydraulic composition contains other components (additives) such as gypsum, inorganic fine powder, thickener, antifoaming agent, water reducing agent, ink, pigment, dispersant, setting modifier, expansion agent, and shrinkage reducing agent. You may

Examples of thickeners include cellulose-based, protein-based, latex-based, modified acrylic-based, and water-soluble polymer-based thickeners. Preferably, the thickener is a modified acrylic or cellulosic thickener. Moreover, a thickener may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the thickener in the hydraulic composition is preferably 0.001 to 1 part by mass, more preferably 0.01 to 0.5 part by mass, based on 100 parts by mass of cement.

The antifoaming agent may be, for example, a mineral oil-based, silicone-based, alcohol-based, polyether-based synthetic substance, or a plant-derived natural substance. is preferably a defoaming agent suitable for defoaming urethane. Specifically, acrylic polymers, vinyl ether polymers, butadiene polymers, olefin polymers, dimethyl silicones, modified silicones, especially polyether-modified silicones, fluorine-modified silicones, alkyl-modified silicones, alkyl/aralkyl-modified silicones, higher aliphatic ester-modified Silicones, higher fatty acid amide-modified silicones, phenyl-modified silicones, mineral oils, nonionic surfactants, anionic surfactants, cationic surfactants, acetylene diols, hydrophobic silica, waxes, metal soaps such as aluminum stearate, Polyoxyalkylene glycols and the like, as well as any combination thereof.

Examples of water reducing agents include naphthalene sulfonate formaldehyde condensate water reducing agents, melamine sulfonate formaldehyde condensate water reducing agents, polycarboxylic acid water reducing agents, ligninsulfonic acid water reducing agents, polystyrene sulfonic acid water reducing agents, Examples include phenol-formaldehyde condensate-based water reducing agents and aniline sulfonic acid-based water reducing agents. The water reducing agent has surfactant-like properties and plays the role of an emulsifier that stably disperses a dispersion obtained by mixing water and a compound having a hydroxyl group. The water reducing agent can improve fluidity of the hydraulic composition and improve workability and workability. The content of the water reducing agent in the hydraulic composition is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of cement.

Surfactants include, for example, sodium lauryl sulfate. The surfactant plays a role of stably dispersing the urethane resin in water. The content of the surfactant in the dispersion is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the dispersion. In addition, known surfactants can be used. Examples of anionic surfactants include sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium polyoxyethylene alkyl ether sulfate, and sodium polyoxyethylene alkylphenyl ether sulfate. Examples include polyoxyethylene alkyl ethers and polyoxyethylene alkylphenyl ethers, and examples of cationic surfactants include alkylammonium salts.

The hydraulic composition of the present embodiment may be a concrete composition or a mortar composition, preferably a mortar composition.

<Method for producing hydraulic composition>
The method for producing the hydraulic composition of the present embodiment is not particularly limited as long as the components (A) and (B) in the hydraulic composition have a predetermined blending ratio. (Step 2), and a step (Step 3) of mixing (A) cement and (B) the aqueous dispersion to obtain a hydraulic composition. wherein the solid content of (B) in the product satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition;
In the production method of the present embodiment, before step 2, a step of heating a mixture of (C) a polyhydric alcohol and (D) a polyisocyanate to obtain a urethane resin (for example, a partially polymerized product containing a urethane compound). (Step 1) may be provided.

In step 1, a mixture of (C) a polyhydric alcohol and (D) a polyhydric isocyanate is heated to obtain a urethane resin. The conditions for obtaining the urethane resin are not particularly limited as long as the hydroxyl group of the (C) polyhydric alcohol and the isocyanate group of the (D) polyvalent isocyanate are reacted. preferable. Also, the heating time is preferably 1 to 5 hours. Step 1 may be performed under an inert atmosphere such as nitrogen or argon.

In step 2, the urethane resin obtained in step 1 is dispersed in water. For example, a urethane resin, a surfactant, and water are mixed to obtain an aqueous dispersion of urethane resin. In the manufacturing method of the present embodiment, since the urethane resin is used as an aqueous dispersion in step 2, it is easy to mix with other components such as cement, and is excellent in workability.

In step 3, the aqueous dispersion obtained in step 2 and cement are mixed so as to satisfy the condition (1) or (2). Mixing may be performed by a Hobart mixer or the like. Other additives may be blended with the cement together with the partial polymer, or may be blended after the dispersion and cement are mixed. Aggregate and additional water may also be added to the cement together with the dispersion, or after mixing the dispersion and cement.

<Method for producing cured product>
The method for producing the hardened product (cement-based hardened product) is not particularly limited, but includes a step of molding the hydraulic composition to obtain a molded product (step 4) and a step of curing the molded product (step 5). You can The molding method is not particularly limited, and the hydraulic composition is poured into a mold (a mold made of metal, plastic, etc.). Degassing with a vibrator may be performed as necessary. A molding is obtained by leaving the hydraulic composition in the mold for, for example, about 1 to 5 days. When a core material such as a reinforcing bar or steel frame is used, the hydraulic composition may be poured after placing the core material in the mold in advance.

In step 5, the molding obtained in step 4 is cured. The mold may be removed before curing. The curing method is not particularly limited, and any curing method such as sealing curing or underwater curing may be used. Curing is performed until the hydraulic composition is solidified.

Since the cured product of the present embodiment has high strength and low water absorption, it can be used for various purposes such as building materials and wave-dissipating blocks. In particular, it is useful as a material for bearing parts of bridges or viaducts, wave-dissipating blocks, etc., which partially or frequently come into contact with water when in use.

<Preparation of urethane resin>
Using a balance, 314.89 g of Actcol ED28 ((C1) component, manufactured by Mitsui Chemicals SKC Polyurethane Co., Ltd.), 41.63 g of dipropylene glycol ((C2) component), 102.94 g of EXCENOL 5030 ((C3) Component, manufactured by AGC Co., Ltd.) were put into the separable flask body while being weighed.
The polyhydric alcohol was mixed while supplying _N2 gas.
138.55 g of Coronate T-100 (polyvalent isocyanate, manufactured by Tosoh Corporation) was weighed and put into the separable flask main body. The mixture was heated at 100° C. for 3 hours while stirring to prepare a urethane resin.
The degree of reaction progress of the urethane resin was evaluated based on JIS K 7301, and the end point was set when the content of isocyanate groups became substantially equal to the content of hydroxyl groups of all polyhydric alcohols.

<Preparation of urethane resin dispersion>
The urethane resin shown in Table 1 was dispersed in water mixed with the surfactant shown in the same table. Specifically, a surfactant (sodium lauryl sulfate) was added to a predetermined amount of water, then a urethane resin was added, and the mixture was stirred for 1 to 3 hours to obtain an aqueous dispersion.

<Preparation of hydraulic composition>
Each component was blended in the amount shown in Table 1. Specifically, first, cement, silica sand, and additives (thickener, water reducing agent, etc.) were weighed, put into a Hobart mixer, and mixed for 1 minute to obtain a mixture.
Then, the urethane resin dispersed in water prepared as described above was added to the mixture and mixed with a Hobart mixer. In order to prevent poor mixing, the Hobart mixer was stopped after the start of mixing (for example, for about 1 minute), and the material attached to the stirring blades and pot was removed. Mixing was started again, the Hobart mixer was stopped (mixing was performed for about 3 to 5 minutes in total), and a hydraulic composition was obtained.
The prepared hydraulic composition was placed in a mold. After one day, the mold was removed to obtain a molded body. The molded body was submerged in water and cured for 28 days (underwater curing) to obtain a specimen.

The symbols in Table 1 have the following meanings.
c/s: mass ratio of cement to aggregate (cement/aggregate)
p/c: Mass ratio of urethane resin to cement (urethane resin/cement)
p: Blending amount of urethane resin (g)
D1: Amount of antifoaming agent (g)
C: Amount of cement (g)
S: Blending amount (g) of fine aggregate (silica sand)
A: Blending amount of water reducing agent (g)
W: Water content Su: Surfactant content (g)
The cement, water reducing agent and antifoaming agent used were as follows.
Cement: high-early-strength Portland cement (Blaine specific surface area 4500 cm ² /g, manufactured by Ube-Mitsubishi Cement Co., Ltd.)
Water reducing agent: Mighty 21P (manufactured by Kao Chemical Co., Ltd.)
Defoamer: BYK1794 (manufactured by BYK Chemie Japan Co., Ltd.)

<Method for measuring compressive strength>
(compressive strength)
A compressive strength test was performed on each specimen of Examples and Comparative Examples. The compressive strength test method followed the method described in JIS A 1171-2016 "Test method for polymer cement mortar".
Table 1 shows the test results.

<Method for measuring water absorption level>
It was measured according to the method described in JSCE-G 582-2018 "Test method for moisture permeation rate coefficient in concrete subjected to short-term water exposure".

Claims (10)

A hydraulic composition obtained by blending (A) cement with (B) an aqueous dispersion of a urethane resin,
The (B) component is formed by a polymerization reaction of at least one (C) polyhydric alcohol and at least one (D) polyhydric isocyanate,
A hydraulic composition in which the solid content of (B) satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition; A hydraulic composition according to claim 1, wherein said aqueous dispersion comprises a surfactant. (A) cement, (B) urethane resin, and (E) a surfactant,
The (B) component is formed by a polymerization reaction of at least one (C) polyhydric alcohol and at least one (D) polyhydric isocyanate,
A hydraulic composition in which the content of (B) satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition; 4. The hydraulic composition according to any one of claims 1 to 3, wherein the component (C) comprises (C1) an ethylene oxide adduct or a propylene oxide adduct of a dihydric alcohol. 5. The hydraulic composition according to claim 4, wherein the component (C1) is an ethylene oxide adduct of polypropylene oxide. The hydraulic composition according to any one of claims 1 to 5, wherein the component (C) contains (C2) a short-chain dihydric alcohol having a molecular weight of 200 or less. The hydraulic composition according to any one of claims 1 to 6, wherein the component (C) contains (C3) a trihydric or higher alcohol. Hydraulic composition according to any one of claims 1 to 7, further comprising aggregate. A cured product, which is a cured product of the hydraulic composition according to any one of claims 1 to 8. a step of obtaining an aqueous dispersion in which a urethane resin formed by a polymerization reaction of a polyhydric alcohol and a polyvalent isocyanate is dispersed in water;
a step of mixing the cement and the aqueous dispersion to obtain a hydraulic composition;
A method for producing a hydraulic composition, wherein the content of the urethane resin in the hydraulic composition satisfies at least one of the following conditions (1) and (2).
(1) 25 parts by mass or less per 100 parts by mass of component (A).
(2) 7% by mass or less with respect to 100% by mass of the total amount of the hydraulic composition;