JP7827872B2 - Additives for hydraulic compositions for additive manufacturing - Google Patents

Description

The present invention relates to a technology for producing hydraulic compositions for additive manufacturing, and in particular to additives used in hydraulic compositions for additive manufacturing.

In recent years, additive manufacturing (3D printing) technology has been utilized in the manufacturing industry to create models and parts. These technologies can be categorized into three types: stereolithography (a method of curing and layering UV-curable resin one layer at a time), inkjet printing (a method of spraying UV-curable resin from a printer head while irradiating it with UV light), powdered gypsum printing (a method of spraying resin or glue from a printer head to harden powdered gypsum), powder sintering (a method of baking and hardening resin or metal powder with a laser to create layers), and fused deposition modeling (a method of ejecting molten thermoplastic resin from a thin nozzle to create layers). The objects are primarily made of resin, gypsum, and metal. Technology for creating large objects, such as construction components, using hydraulic material compositions has been explored more overseas than in Japan. In Europe, the United States, and China, automated construction machinery is already being used to produce large objects the size of single-family homes.

For example, the following Patent Documents 1 to 5 introduce technologies related to additive manufacturing using hydraulic compositions.

Patent document 1 discloses a technology in which three-dimensional data created by a computer is cut at a predetermined thickness to create two-dimensional slice data, and mortar mixed with an added quick-setting agent is sprayed onto a bed (table) while controlling the movement of a spray nozzle in the vertical and horizontal directions based on the two-dimensional slice data, and the sprayed mortar is allowed to harden on its own, forming a solidified layer in the shape based on the two-dimensional slice data, and this solidified layer formation process is repeated to stack the layers in the vertical direction to create a shape.

Patent document 2 introduces a material for using a 3D printer to create molds for producing castings, and discloses a material consisting of cement, sand, and a water-soluble silicate as an accelerator.

Patent document 3 introduces a grout composition that uses a combination of a lignin sulfonate-based dispersant and a melamine sulfonate-based dispersant as a hydraulic material composition.

Patent document 4 introduces PC grout as a material that combines a dispersant and a thickener.

Patent document 5 discloses a method for producing a hydraulic composition for additive manufacturing using an ionic emulsion-type thickener.

The fluidity of hydraulic compositions for additive manufacturing (3D printing) must be reduced in order to achieve layering properties. However, reducing the fluidity of the hydraulic material composition hinders its movement within the hose, so the current situation is that the only solution is to add a hardening accelerator just before dispensing to reduce fluidity. Furthermore, regarding layering properties themselves, it is currently believed that there are numerous issues that need to be resolved in order to further popularize construction using additive manufacturing.

Japanese Patent Application Publication No. 10-235623 U.S. Patent No. 8,211,226 Japanese Patent Application Laid-Open No. 2008-247677 Japanese Patent Application Laid-Open No. 2006-290694 Japanese Patent Application Laid-Open No. 2021-133667

The present invention aims to provide additives and the like that have excellent effects, such as improving the lamination properties of hydraulic compositions for additive manufacturing.

After extensive research, the inventors discovered that certain polymers are useful for improving lamination properties. Based on this finding, the inventors have completed the present invention.

Details of each of the additives and other aspects of the present invention are explained below. However, the following descriptions are merely examples for the purpose of explaining the present invention and are not intended to limit the present invention to the scope of the descriptions. Furthermore, any combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention and is considered to be disclosed in this specification (i.e., it is a legitimate basis for amendment).

In addition, in this specification, the range "X to Y" means "X or more and Y or less," and unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20-25°C) and a relative humidity of 45-55% RH. In addition, in this specification, the term "(meth)acrylic" means "acrylic and/or methacrylic," and the term "(meth)acrylate" means "acrylate and/or methacrylate." Furthermore, "weight" and "mass," "parts by weight" and "parts by mass," and "wt%" and "mass%" are treated as synonyms.

(Example of the present invention)
Preferred configurations of the additives of the present invention are described in the following items (1) to (8).
(1) An additive for a hydraulic composition for additive manufacturing, comprising a polymer having the following structural unit (I):

(In the structural unit (I), X is C═O or (CH ₂ ) _p [p is an integer of 0 to 5], R ⁴ O is an oxyalkylene group having 2 to 8 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of 15 to 500, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and the remaining R ¹ to R ³ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms.)
(2) The additive according to (1) above, wherein n is 100 to 500.
(3) The additive according to (1) or (2) above, wherein X is (CH ₂ ) _p [p is an integer of 0 to 2].
(4) The additive according to any one of (1) to (3), wherein the polymer contains 50 to 100 parts by weight of the structural unit (I) per 100 parts by weight of the polymer.
(5) The additive according to any one of (1) to (4), wherein the polymer is a copolymer further containing the following structural unit (II):

(In the structural unit (II), R ⁶ to R ⁸ are the same or different and represent a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a carboxyl group, and M represents a hydrogen atom or a cation species.)
(6) The additive according to any one of (1) to (5), wherein the polymer is a copolymer containing a structural unit derived from an unsaturated monomer having at least one group selected from the group consisting of a sulfonic acid group, a phosphoric acid group, and a salt thereof.
(7) A hydraulic composition for additive manufacturing, comprising the additive according to any one of (1) to (6).
(8) a step of mixing and stirring a hydraulic composition and the additive described in any one of (1) to (6);
A method for producing a hydraulic composition for layered manufacturing, comprising:

Hereinafter, an additive for a hydraulic composition for additive manufacturing, which contains a polymer having structural unit (I), will also be referred to as the additive of the present invention. Furthermore, a polymer having structural unit (I) will also be referred to as the polymer of the present invention.

The additives of the present invention have excellent effects, such as improving the lamination properties of hydraulic compositions for additive manufacturing.

Here, improved lamination ability refers to, for example, a high lamination index, which will be described later. Specifically, improved lamination ability refers to the ability of a hydraulic composition, such as mortar or fresh concrete formed from the hydraulic composition, to form a desired height, and to maintain the desired height before the hydraulic composition completely hardens. The additive of the present invention can increase the lamination index of the hydraulic composition for additive manufacturing.

(Additives)
The additive of the present invention is used in a hydraulic composition for layered manufacturing. The additive of the present invention is preferably used by being kneaded with a hydraulic composition such as mortar or fresh concrete.

More specifically, the additive of the present invention comprises a polymer having at least the following structural unit (I). Preferably, the additive of the present invention comprises a polymer having at least the following structural unit (I) as a main component. Here, "main component" means that the polymer in question accounts for 80% by weight or more (preferably 90% by weight or more, more preferably 95% by weight or more) of the additive. More preferably, the additive of the present invention consists of a polymer having at least the following structural unit (I).

The additives of the present invention can be more specifically limited in their use as thickeners or layerability improvers.

A specific method of using the additive of the present invention is to add it to a hydraulic composition such as mortar or fresh concrete for additive manufacturing and stir it in.

(Additive manufacturing)
In the present invention, "additive manufacturing" refers to a technology for manufacturing molded bodies of any shape by layering cross-sectional shapes based on three-dimensional data without using specialized tools such as molds. This technology is also commonly called "3D printing,""three-dimensionalmodeling," or "rapid prototyping."

(Hydraulic composition for additive manufacturing)
In the present invention, the "hydraulic composition for additive manufacturing" refers to a hydraulic composition used for additive manufacturing. The hydraulic composition contains a hydraulic material and aggregate (coarse aggregate and/or fine aggregate), and optionally contains other components such as an antifoaming agent and a dispersant. Examples of hydraulic compositions include mortar and fresh concrete.

The hydraulic composition for additive manufacturing of the present invention preferably contains the additive of the present invention in addition to the hydraulic composition. The hydraulic composition for additive manufacturing preferably contains the additive of the present invention in an amount of 0.01 to 1.0% by weight relative to the hydraulic substance (cement).

(hydraulic material)
The "hydraulic material" used in the present invention refers to a hydraulic substance, a pozzolanic reactive substance, or a latent hydraulic substance, and preferably contains a hydraulic substance. When the hydraulic material contains a pozzolanic reactive substance or a latent hydraulic substance, it is desirable that the hydraulic material further contains cement (or calcium hydroxide) and a stimulant.

(hydraulic substance)
The "hydraulic material" in the present invention refers to so-called cement, and examples of cement include Portland cement (normal, early-strength, ultra-early-strength, moderate-heat, low-heat, sulfate-resistant, and their low-alkali forms), various blended cements (blast-furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, ultra-rapid-hardening cement (1-clinker rapid-hardening cement, 2-clinker rapid-hardening cement, magnesium phosphate cement), cement for grouting, oil well cement, low-heat cement (low-heat blast-furnace cement, low-heat blast-furnace cement mixed with fly ash, high-belite cement), ultra-high-strength cement, cement-based solidification material, and ecocement (cement produced using one or more of municipal waste incineration ash and sewage sludge incineration ash as raw materials). The cement in the present invention may be one type, or two or more types.

(Pozzolanic reactive substances)
In the present invention, a "pozzolanic reactive substance" is a substance that does not have hydraulic properties by itself, but gradually combines with components in concrete (for example, calcium hydroxide produced by cement hydration) to form an insoluble compound (for example, calcium silicate hydrate). Examples of such a substance include natural pozzolan, fly ash, cinder ash, clinker ash, husk ash, metakaolin, and silica fume, with fly ash being preferred. Fly ash comes in types I, II, III, and IV, with type II being preferred. The pozzolan reactive substance is desirably in the form of granules with a particle size of 0.01 to 10 mm.

(Latent hydraulic substance)
The "latent hydraulic substance" in this invention is a substance that does not harden simply by mixing with water, but hardens in the presence of a small amount of a substance called a stimulant, such as slag (blast furnace slag, slowly cooled blast furnace slag, steelmaking slag, etc.). The latent hydraulic substance is preferably in the form of granules with a particle size of 0.01 to 10 mm.

Examples of stimulants include aqueous solutions of alkali metal carbonates, aqueous solutions of alkali metal fluorides, aqueous solutions of alkali metal hydroxides, aqueous solutions of alkali metal aluminates, aqueous solutions of alkali metal silicates (e.g., water glass) and/or mixtures thereof, which can be added to compositions containing the latent hydraulic material of the present invention.

(aggregate)
The aggregate used in the present invention may be any appropriate aggregate, such as fine aggregate (sand, etc.) or coarse aggregate (crushed stone, etc.). Examples of such aggregate include sand, gravel, crushed stone, granulated slag, recycled aggregate, and refractory aggregate such as silica, clay, zircon, high alumina, silicon carbide, graphite, chromium, chromium-magnesium, and magnesia.

(Antifoaming agent)
Examples of the defoaming agent include polyoxyalkylene alkyl ethers such as diethylene glycol heptyl ether; polyoxyalkylene acetylene ethers; (poly)oxyalkylene fatty acid esters; polyoxyalkylene sorbitan fatty acid esters; polyoxyalkylene alkyl (aryl) ether sulfate ester salts; polyoxyalkylene alkyl phosphate esters; polyoxypropylene polyoxyethylene laurylamine (1 to 20 moles of propylene oxide added, 1 to 20 moles of ethylene oxide added, etc.), and polyoxyalkylene alkylamines such as amines derived from fatty acids obtained from hardened beef tallow to which alkylene oxide has been added (1 to 20 moles of propylene oxide added, 1 to 20 moles of ethylene oxide added, etc.); oxyalkylene defoaming agents such as polyoxyalkylene amide; mineral oil-based, oil-based, fatty acid-based, fatty acid ester-based, alcohol-based, amide-based, phosphate ester-based, metal soap-based, and silicone-based defoaming agents.

(Structural Unit (I))
The polymer in the present invention has the following structural unit (I).

In the structural unit (I) above, X is C═O or (CH ₂ ) _p [p is an integer of 0 to 5], R ⁴ O is an oxyalkylene group having 2 to 8 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of 15 to 500, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and the remaining R ¹ to R ³ may be the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. Needless to say, different types of structural units (I) may be contained in the polymer.

The above X is preferably (CH ₂ ) _p [p is an integer of 0 to 5], more preferably (CH ₂ ) _p [p is 0 to 2], and even more preferably (CH ₂ ) _p [p is 1] (when p=0, the upper C and lower O of X in the structural unit (I) are directly bonded). The above R ⁴ O is preferably an oxyalkylene group having 2 to 4 carbon atoms, and more preferably an oxyalkylene group having 2 carbon atoms.

In addition, from the viewpoint of the effects of the present invention, the above n may be 20 to 500, 25 to 500, 30 to 500, or 50 to 500, preferably 75 to 500, more preferably 100 to 500, even more preferably 150 to 500, particularly preferably 200 to 500, and most preferably 200 to 400. When n is above the above lower limit, lamination properties are further improved, and when n is below the upper limit, the polymer becomes easier to handle.

^R5 above is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and from the viewpoint of the effects of the present invention, is preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom. ^R1 to ^R3 above may be the same or different and are each a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group. More preferably, at least one of ^R1 to ^R3 is a hydrocarbon group having 1 to 8 carbon atoms, and one or two may be a hydrocarbon group having 1 to 8 carbon atoms. More specific examples of the hydrocarbon group include linear, branched, and cyclic alkyl groups (for example, linear, branched, and cyclic alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, and 2-ethylhexyl), alkenyl groups, aryl groups, and aralkyl groups, of which alkyl groups are preferred, and methyl groups are particularly preferred.

The structural unit (I) may be a structural unit formed upon cleavage of the carbon-carbon double bond of a monomer containing a polyalkylene glycol group (hydroxyl group terminal), an alkoxypolyalkylene glycol group (alkyl group terminal), or a phenoxypolyalkylene glycol group (aryl group terminal) (hereinafter referred to as a polyalkylene glycol group-containing monomer). Examples of such polyalkylene glycol group-containing monomers include unsaturated polyalkylene glycol ester-based monomers and unsaturated polyalkylene glycol ether-based monomers. In particular, the structural unit (I) is preferably a structural unit formed upon cleavage of the carbon-carbon double bond of an unsaturated polyalkylene glycol ester-based monomer and/or an unsaturated polyalkylene glycol ether-based monomer, and more preferably a structural unit formed upon cleavage of the carbon-carbon double bond of an unsaturated polyalkylene glycol ether-based monomer.

Examples of the above-mentioned unsaturated polyalkylene glycol ester monomer include polyalkylene glycol monomethacrylate, polyalkylene glycol monoacrylate, alkoxypolyalkylene glycol monomethacrylate, alkoxypolyalkylene glycol monoacrylate, phenoxypolyalkylene glycol monomethacrylate, and phenoxypolyalkylene glycol monoacrylate. Preferred are alkoxypolyalkylene glycol monomethacrylate and alkoxypolyalkylene glycol monoacrylate, and more preferred are alkoxypolyalkylene glycol monomethacrylate and alkoxypolyalkylene glycol monoacrylate.

Examples of the alkoxypolyalkylene glycol monomethacrylate include methoxypolyethylene glycol methacrylate, octoxypolyethylene glycol-polypropylene glycol methacrylate, lauroxypolyethylene glycol methacrylate, and stearoxypolyethylene glycol methacrylate, with methoxypolyethylene glycol methacrylate being preferred.

Examples of the above alkoxypolyalkylene glycol monoacrylates include methoxypolyethylene glycol-acrylate, octoxypolyethylene glycol-polypropylene glycol-acrylate, lauroxypolyethylene glycol-acrylate, and stearoxypolyethylene glycol-acrylate.

Examples of the above-mentioned phenoxypolyalkylene glycol monomethacrylate include phenoxypolyethylene glycol methacrylate.

Examples of the above alkoxypolyalkylene glycol monoacrylate include methoxypolyethylene glycol acrylate.

Examples of the above-mentioned phenoxypolyalkylene glycol monoacrylate include nonylphenoxypolypropylene glycol-acrylate and nonylphenoxypolyethylene glycol-polypropylene glycol acrylate.

Examples of the above polyalkylene glycol monomethacrylate include polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, polyethylene glycol propylene glycol monomethacrylate, polyethylene glycol tetramethylene glycol monomethacrylate, and propylene glycol polybutylene glycol monomethacrylate.

Examples of the above polyalkylene glycol monoacrylate include polyethylene glycol monoacrylate and polypropylene glycol monoacrylate.

Examples of the unsaturated polyalkylene glycol ether monomer include compounds in which 15 to 500 moles of alkylene oxide are added to the hydroxyl groups of any of vinyl alcohol, allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, 2-methyl-3-buten-2-ol, 2-methyl-2-buten-1-ol, 2-methyl-3-buten-1-ol, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, and hydroxybutyl vinyl ether, and preferably 3 Examples of the alkylene oxide include a compound obtained by adding 15 to 500 moles (preferably 50 to 500 moles) of alkylene oxide to 3-methyl-3-buten-1-ol, a compound obtained by adding 15 to 500 moles (preferably 50 to 500 moles) of alkylene oxide to allyl alcohol, and a compound obtained by adding 15 to 500 moles (preferably 50 to 500 moles) of alkylene oxide to methallyl alcohol, more preferably a compound obtained by adding 15 to 500 moles of alkylene oxide to allyl alcohol and/or a compound obtained by adding 15 to 500 moles of alkylene oxide to methallyl alcohol. The alkylene oxide is preferably ethylene oxide, propylene oxide, or butylene oxide, and most preferably ethylene oxide.

(Structural unit (II))
The polymer in the present invention preferably further contains the following structural unit (II) from the viewpoint of improving the adsorption onto hydraulic compositions such as cement.

In the structural unit (II), R ⁶ to R ⁸ are the same or different and represent a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a carboxyl group, and M represents a hydrogen atom or a cationic species (preferably, in terms of the effects of the present invention, M represents a cationic species). Needless to say, different types of structural units (II) may be contained in the polymer.

The above R ⁶ to R ⁸ may be the same or different and are preferably a hydrogen atom, a hydrocarbon group having 1 to 4 carbon atoms, or a carboxyl group, more preferably a hydrogen atom or a methyl group. More specific examples of the hydrocarbon group include linear, branched, or cyclic alkyl groups (e.g., linear, branched, or cyclic alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, and 2-ethylhexyl), alkenyl groups, aryl groups, and aralkyl groups, among which alkyl groups are preferred, and methyl groups are particularly preferred. Specific examples of the cation species include lithium, sodium, potassium, magnesium, calcium, and aluminum, with sodium being preferred. Two or more types of cation species may be used.

The structural unit (II) may be a structural unit formed upon cleavage of a carbon-carbon double bond in an unsaturated carboxylic acid monomer. Examples of such unsaturated carboxylic acid monomers include acrylic acid, methacrylic acid, crotonic acid, tiglic acid, 3-methylcrotonic acid, 2-methyl-2-pentenoic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, 2-methylene glutaric acid, and salts thereof. Examples of salts include lithium salts, sodium salts, potassium salts, magnesium salts, calcium salts, and aluminum salts, with sodium salts being preferred. The unsaturated carboxylic acid monomer is preferably acrylic acid (salt), methacrylic acid (salt), maleic acid (salt), or fumaric acid (salt), more preferably acrylic acid (salt) and/or methacrylic acid (salt), even more preferably acrylates and/or methacrylates, and even more preferably sodium acrylate and/or sodium methacrylate. Here, acrylic acid (salt) refers to acrylic acid and/or an acrylic acid salt, and methacrylic acid (salt) refers to methacrylic acid and/or a methacrylic acid salt.

(Other structural units)
The polymer of the present invention may contain structural units other than the above structural units (I) and (II) in the remainder.

Examples of the remaining structural units include structural units derived from unsaturated monomers having a sulfonic acid group and/or a salt thereof, structural units derived from unsaturated monomers having a phosphate group and/or a salt thereof, and structural units derived from (meth)acrylates. In particular, from the perspective of improving adsorption to hydraulic compositions such as cement, the polymer of the present invention preferably contains, as the remaining structural unit, at least one selected from the group consisting of structural units derived from unsaturated monomers having a sulfonic acid group and/or a salt thereof and structural units derived from unsaturated monomers having a phosphate group and/or a salt thereof, and more preferably structural units derived from unsaturated monomers having a sulfonic acid group and/or a salt thereof.

In this specification, the term "structural unit derived from a monomer" refers to a structural unit formed by polymerization of a monomer, and more specifically, refers to a structure formed by cleavage of a carbon-carbon double bond in a monomer. In addition, in this specification, the term "(meth)acrylate" refers to acrylate and/or methacrylate.

Examples of the unsaturated monomer having a sulfonic acid group and/or a salt thereof include vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-(methacryloyloxy)ethanesulfonic acid, sulfonic acids represented by the following formula (III) or salts thereof, more preferably 2-acrylamido-2-methylpropanesulfonic acid, sulfonic acids represented by the following formula (III) or salts thereof, and most preferably sodium 3-allyloxy-2-hydroxypropanesulfonate. These unsaturated monomers may be used alone or in combination of two or more.

The polymer of the present invention may contain the above structural unit (I), the above structural unit (II), and further a structural unit derived from an unsaturated monomer having a sulfonic acid group and/or a salt thereof. Alternatively, the polymer of the present invention may contain the above structural unit (I) and a structural unit derived from an unsaturated monomer having a sulfonic acid group or a salt thereof, without containing the above structural unit (II).

In the structural unit (III), p represents an integer of 1 to 4; q and r are the same or different and represent an integer of 0 to 100 (preferably an integer of 0 to 50, more preferably an integer of 0 to 20); R ⁹ and R ¹⁰ are oxyalkylene groups having 2 to 4 carbon atoms; Y and Z are the same or different and represent a hydroxy group, an alkoxyl group having 2 to 4 carbon atoms, a monovalent phosphate group, or a monovalent sulfonic acid group, and at least one of Y and Z represents a sulfonic acid group.

Examples of the unsaturated monomer having the above-mentioned phosphate group and/or its salt group include hydroxyalkyl (meth)acrylate monophosphate esters or salts thereof, such as hydroxyethyl methacrylate monophosphate ester, hydroxyethyl propyl methacrylate monophosphate ester, and hydroxyethyl butyl methacrylate monophosphate ester.

The polymer of the present invention may not contain the structural unit (II) but may contain the structural unit (I) and a structural unit derived from the unsaturated monomer, which is phosphoric acid and/or a salt thereof.

Examples of the (meth)acrylate include hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate, and alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate, with hydroxyethyl (meth)acrylate or hydroxypropyl (meth)acrylate being preferred. The polymer of the present invention may contain the structural unit (I) described above, the structural unit (II) described above, and further a structural unit derived from the (meth)acrylate described above.

(Polymer structure)
The polymer of the present invention preferably contains 10.0 to 100.0 parts by weight, more preferably 50.0 to 100.0 parts by weight, even more preferably 75.0 to 99.0 parts by weight, and even more preferably 80.0 to 99.0 parts by weight of the structural unit (I) relative to 100 parts by weight of the polymer. The polymer of the present invention also preferably contains 1.0 to 30.0 parts by weight, more preferably 2.0 to 20.0 parts by weight, even more preferably 2.0 to 15.0 parts by weight, and even more preferably 2.0 to 10.0 parts by weight of the structural unit (II) relative to 100 parts by weight of the polymer. The remaining structural units are contained in the polymer in an amount of, for example, 1.0 to 30.0 parts by weight relative to 100 parts by weight of the polymer of the present invention.

The polymer of the present invention preferably contains structural units (I) and (II) (including those consisting of or essentially consisting of (I) and (II) (for example, 99.0 parts by weight or more of (I) and (II) per 100 parts by weight of all structural units)). In this case, the remaining structural units may be contained in the polymer in an amount of, for example, 1.0 to 20.0 parts by weight, or 1.0 to 10.0 parts by weight per 100 parts by weight of the polymer. Furthermore, in addition to containing structural units (I) and (II), it is also a preferred embodiment that the remaining structural units include at least one selected from the group consisting of structural units derived from unsaturated monomers having a sulfonic acid group and/or a salt group thereof, and structural units derived from unsaturated monomers having a phosphate group and/or a salt group thereof.

Furthermore, the polymer of the present invention preferably contains structural units (I) and structural units derived from unsaturated monomers having a sulfonic acid group and/or a salt thereof (including those consisting of, or essentially consisting of, structural units derived from (I) and unsaturated monomers having a sulfonic acid group and/or a salt thereof (for example, 99.0 parts by weight or more of structural units derived from (I) and unsaturated monomers having a sulfonic acid group or a salt thereof per 100 parts by weight of all structural units)). In this case, the structural units derived from unsaturated monomers having a sulfonic acid group and/or a salt thereof may be contained in the polymer in a total amount of, for example, 1.0 to 30.0 parts by weight, 5.0 to 30.0 parts by weight, or 10.0 to 25 parts by weight per 100 parts by weight of the polymer.

Examples of polymerizations in the present invention include copolymerizations of (1) a monomer containing a polyalkylene glycol group, etc., and (2) an unsaturated carboxylic acid monomer, and copolymerizations of (1) a monomer containing a polyalkylene glycol group, etc., and an unsaturated monomer having a sulfonic acid group and/or a salt thereof.

The weight-average molecular weight of the polymer in the present invention, as determined using static light scattering or the method described in the Examples below (preferably the method described in the Examples below), is, for example, 1,000 to 10,000,000, preferably 2,000 to 8,000,000, more preferably 3,000 to 6,000,000, even more preferably 4,000 to 5,000,000, even more preferably 10,000 to 500,000, and particularly preferably 10,000 to 100,000.

(Polymerization method)
The polymerization for obtaining the polymer according to the present invention may be carried out in the presence of a polymerization initiator.

Examples of polymerization initiators include azo compounds such as azobisisobutyronitrile, 2,2-azobis(2-methylbutyronitrile), 2,2-azobis(2,4-dimethylvaleronitrile), 2,2-azobis(2-diaminopropane) hydrochloride, 4,4-azobis(4-cyanovaleric acid), and 2,2-azobis(2-methylpropionamidine); persulfates such as potassium persulfate; and peroxides such as hydrogen peroxide, benzoyl peroxide, parachlorobenzoyl peroxide, lauroyl peroxide, and ammonium peroxide. In this case, accelerators such as alkali metal sulfites such as sodium bisulfite, metabisulfite, sodium hypophosphite, Fe(II) salts such as Mohr's salt, sodium hydroxymethanesulfinate dihydrate, hydroxylamine hydrochloride, thiourea, L-ascorbic acid (salt), and erythorbic acid (salt) can also be used in combination.

Polymerization initiators may be used singly or in combination of two or more.

The amount of polymerization initiator used can be set appropriately depending on the type of polymerization initiator, etc., and is not particularly limited. However, it may be, for example, 0.05 parts by weight or more, preferably 0.1 parts by weight or more, per 100 parts by weight of the monomer component, or, for example, 2 parts by weight or less, preferably 1 part by weight or less.

The method of adding the polymerization initiator is not particularly limited, but examples include adding it all at once, adding it in portions, or adding it continuously by dripping.

The polymerization reaction may be carried out, as necessary, in the presence of a reducing agent (e.g., sodium bisulfite), a decomposing agent for the polymerization initiator (e.g., a transition metal salt such as ferrous sulfate), a chain transfer agent [e.g., a compound having a thiol group (e.g., tert-dodecyl mercaptan, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, etc.)], a pH buffer, a chelating agent, etc. The atmosphere during polymerization is not particularly limited, but may be an inert gas such as nitrogen gas from the standpoint of polymerization efficiency, etc.

The polymerization temperature is not particularly limited, but may be, for example, 50 to 100°C, preferably 60 to 95°C. The polymerization temperature may be constant or may be changed during the polymerization reaction. The polymerization time is not particularly limited and may be set appropriately depending on the progress of the polymerization reaction, but may be, for example, 1 hour or more (e.g., 1 to 24 hours), preferably 2 to 12 hours (e.g., 2 to 9 hours).

(Hydraulic composition for additive manufacturing)
The hydraulic composition for additive manufacturing of the present invention may be mortar or fresh concrete for additive manufacturing. Examples of methods for producing the hydraulic composition for additive manufacturing include a method comprising mixing and stirring a hydraulic composition and the additive of the present invention. Another example is a method comprising (a) a stirring step of stirring the hydraulic composition and water, and (b) a stirring step of adding the additive of the present invention to the mixture obtained after the stirring step and stirring the mixture. In the method, steps (a) and (b) are carried out independently, with step (b) being carried out after step (a).

Furthermore, after the above steps in the manufacturing method, it is desirable that the fresh concrete be layered on top of another fresh concrete immediately (for example, within 0 to 300 seconds after the above steps).

<Layered object and layered manufacturing method>
The hydraulic composition of the present invention is suitable for use in layer-by-layer manufacturing. Therefore, the present invention also provides a layer-by-layer manufactured article formed from the hydraulic composition for layer-by-layer manufacturing of the present invention.

Another embodiment is a method for producing an additive manufacturing object using the hydraulic material composition of the above embodiment.

A method for producing an additive manufacturing object using the hydraulic material composition for additive manufacturing (additive manufacturing method) includes the steps of extruding the hydraulic composition of the above embodiment from a nozzle and laminating the hydraulic composition. The additive manufacturing method according to this embodiment preferably includes the steps of: pressurizing the hydraulic composition for additive manufacturing using compressed air, a pump, or the like; and extruding the pressurized hydraulic composition for additive manufacturing through a nozzle and laminating the hydraulic composition for additive manufacturing to form an additive manufacturing object. Because the additive of the present invention can improve lamination properties without reducing the fluidity of the hydraulic composition, it is preferable to add the additive of the present invention before pressurizing the hydraulic composition using compressed air, a pump, or the like. That is, the method for producing a layered object using the hydraulic material composition for layered object manufacturing (layered object manufacturing method) includes the steps of preparing a hydraulic composition for layered object manufacturing containing the additive of the present invention, pressurizing the obtained hydraulic composition for layered object manufacturing using compressed air, a pump, or the like, and extruding the pressurized hydraulic composition for layered object manufacturing from a nozzle to laminate the hydraulic composition for layered object manufacturing.

A nozzle (discharge section) is usually provided at the end of the pressure-feeding pipe for the hydraulic material composition for additive manufacturing. The diameter of the nozzle is not particularly limited, but can be set appropriately depending on the size of the aggregate used and the width over which the hydraulic material composition for additive manufacturing is to be layered. For example, if the aggregate size is 5 mm or less and the layer width is 50 mm or less, a nozzle diameter of 8 to 15 mm is preferred. The shape of the nozzle is not particularly limited, but examples include circular, elliptical, rectangular, cross, and star shapes. A brim may be provided around the nozzle to impart smoothness to the surface of the discharged hydraulic material composition.

When building a structure by layering the hydraulic material composition for additive manufacturing dispensed from a nozzle, the nozzle may be moved vertically or horizontally to form the structure. For example, it is preferable to fix the nozzle to a robot arm or portal plotter and control the nozzle movement by computer. One possible method involves cutting computer-generated 3D data at a predetermined thickness to create 2D slice data, then discharging the hydraulic material composition for additive manufacturing from the nozzle while controlling the horizontal movement of the spray nozzle in vertical, horizontal, or diagonal directions based on the 2D slice data. The nozzle is then moved vertically, repeatedly to form successive layers. The nozzle movement speed is not particularly limited and can be varied depending on the width of the layer.

The present invention will now be described in more detail based on examples, but the present invention is not limited to these examples. In the following, unless otherwise specified, "parts" means parts by weight and "%" means "% by weight."

Example 1
An aqueous solution (B1a) was prepared by dissolving 0.4 parts of L-ascorbic acid and 0.8 parts of 3-mercaptopropionic acid in 50.0 parts of water. A thermometer, a stirrer, a dropping device, a nitrogen inlet tube, and a reflux condenser were equipped in a reaction vessel. 90.4 parts of water, 191.0 parts of an unsaturated polyalkylene glycol ether monomer (IPN-50) in which an average of 50 moles of ethylene oxide were added to 3-methyl-3-buten-1-ol, and 0.3 parts of acrylic acid (AA) were then charged. The atmosphere in the reaction vessel was then purged with nitrogen under stirring, and the temperature was raised to 60 ° C. under a nitrogen atmosphere. 0.9 parts of a 35% aqueous solution of hydrogen peroxide was then added. 30 minutes later, the above-mentioned mixed solution (B1a) was added over 3.5 hours, and 25.5 parts of acrylic acid (AA) were added over 3.0 hours, each at a constant rate. The temperature during this period was kept constant at 60 ° C. After the dropwise addition of the mixed solution (B1a) was completed, the temperature was maintained at 60°C for 1 hour to terminate the polymerization reaction. The pH of the reaction solution was then neutralized to pH = 6.3 using aqueous sodium hydroxide at a temperature below the polymerization reaction temperature. In this way, an aqueous solution containing the target polymer was obtained. The weight average molecular weight Mw of the polymer was 32,000.

The weight average molecular weight Mw of the polymer was measured by GPC (gel permeation chromatography) under the following conditions.
- Device name: Waters Alliance e2695
Columns used: TSKguard column α + TSKgel α-5000 + TSKgel α-4000 + TSKgel α-3000 manufactured by Tosoh Corporation were connected together and used.
Eluent: A solution prepared by dissolving 62.4 g of sodium dihydrogen phosphate·2H ₂ O and 143.3 g of disodium hydrogen phosphate·12H ₂ O in 7794.3 g of ion-exchanged water and mixing this with 2000 g of acetonitrile was used.
Detector: differential refractometer (RI) detector (Waters 2414)
Standard material for preparing calibration curve: Polyethylene oxide (Mw 255,000, 200,000, 107,000, 72,500, 44,900, 31,440, 21,300, 11,840, 6,450, 4,020, 1,470) manufactured by GL Sciences
Calibration curve: A third-order equation was prepared based on the Mw values and elution times of the above standard substances.
Injection amount: Sample and standard: 100 μL of a solution prepared by dissolving the polymer in the eluent so that the polymer concentration was 1.0 vol % was injected.
・Flow rate: 0.5ml/min
Column temperature: 40°C
Measurement time: 90 minutes.

<Examples 2 to 29 and Comparative Examples 1 and 2>
The polymers of Examples 2 to 29 and Comparative Examples 1 and 2 were obtained by carrying out polymerization using the formulations shown in Table 1 below in the same procedure as in Example 1. The molecular weights of these polymers were adjusted by carrying out polymerization while appropriately changing the amount of 3-mercaptopropionic acid added.

IPN50: Unsaturated polyalkylene glycol ether monomer in which an average of 50 moles of ethylene oxide are added to 3-methyl-3-buten-1-ol. PGM25E: Methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 25 moles).
PGM40E: methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide added: 40 moles)
MLA20: Unsaturated alcohol obtained by adding an average of 20 moles of ethylene oxide to methallyl alcohol. MLA50: Unsaturated alcohol obtained by adding an average of 50 moles of ethylene oxide to methallyl alcohol. MLA75: Unsaturated alcohol obtained by adding an average of 75 moles of ethylene oxide to methallyl alcohol. ALA75: Unsaturated alcohol obtained by adding an average of 75 moles of ethylene oxide to allyl alcohol. ALA150: Unsaturated alcohol obtained by adding an average of 150 moles of ethylene oxide to allyl alcohol. ALA250: Unsaturated alcohol obtained by adding an average of 250 moles of ethylene oxide to allyl alcohol. MLA100: Unsaturated alcohol obtained by adding an average of 100 moles of ethylene oxide to methallyl alcohol. MLA150: Unsaturated alcohol obtained by adding an average of 150 moles of ethylene oxide to methallyl alcohol. Saturated alcohol MLA200: unsaturated alcohol obtained by adding an average of 200 moles of ethylene oxide to methallyl alcohol MLA250: unsaturated alcohol obtained by adding an average of 250 moles of ethylene oxide to methallyl alcohol IPN10: unsaturated polyalkylene glycol ether monomer obtained by adding an average of 10 moles of ethylene oxide to 3-methyl-3-buten-1-ol MLA10: unsaturated alcohol obtained by adding an average of 10 moles of ethylene oxide to methallyl alcohol SA: sodium acrylate SMAA: sodium methacrylate HEA: 2-hydroxyethyl acrylate HAPS: sodium 3-allyloxy-2-hydroxy-1-propanesulfonate HPA: hydroxypropyl acrylate AMPS: sodium 2-acrylamido-2-methylpropanesulfonate.

[Test Example 1] Flow Test A flow test was performed in the following manner, with reference to the contents of JIS R5201: 2015. The flow test and the lamination property evaluation test described below were performed in an environment of a temperature of 20±1°C and a relative humidity of 60±15% RH.

First, a 10% polymer solution, which had been prepared in advance by diluting any of the polymers of Examples 1 to 29 and Comparative Examples 1 and 2 with water, was mixed with Adekanol LG-299 (manufactured by Adeka Corporation) as an antifoaming agent, and water to prepare solution (A). Solution (A) was prepared by mixing the 10% polymer solution in an amount such that the result of the flow test below using solution (A) was 196 mm or more and 204 mm or less, mixing Adekanol LG-299 in an amount that was 5% of the solids content of the 10% polymer solution, and mixing water in an amount such that the weight of solution (A) became 331.2 g.

Next, 690 g of ordinary Portland cement (manufactured by Taiheiyo Cement Corporation) was added to the kettle of a high-power mixer (model CB-34; manufactured by Maruto Seisakusho Co., Ltd.), followed by 1,600 g of fine aggregate (Kakegawa sand), and mixing with the mixer was immediately started at low speed. 10 seconds after mixing with the mixer began, solution (A) was added over 10 seconds. 60 seconds after mixing with the mixer began, a 60-second pause was taken, and during the first 30 seconds of the pause, the kettle was removed, and mortar adhering to the kettle and paddle was scraped off using a paddle and spatula. After the pause, mixing was continued at high speed for 60 seconds.

The flow value of each mortar mixed above was measured using a truncated cone-shaped flow cone (lower diameter 100 mm, upper diameter 70 mm, height 60 mm). The detailed conditions for measuring the flow value are as follows:

Cone installation: Before use, the cone was visually inspected to ensure there was no dirt, scratches, or dents. The inner surface of the cone and the top surface of the flow table were wiped clean with a wet cloth or similar.

Flow table: The flow table described in JIS R5201:2015 was used.

Sample filling method: The cone was placed on a horizontally placed flat plate, and the sample was packed in two layers of approximately equal volume. Each layer was leveled with a tamping rod and then poked evenly 25 times to ensure no bias. When tamping each layer, the tamping rod was inserted deep enough to almost reach the previous layer. Finally, if necessary, any shortfalls were made up and the surface was leveled. The cone was immediately removed vertically and allowed to fall a total of 15 times at a frequency of once per second. After the mortar spread, the length in the direction where it was observed to be the maximum and the length perpendicular to this were measured, and the average value was recorded as flow (mm).

[Test Example 2] Lamination Property Evaluation Test One corner of the bottom of a polyethylene bag (200 mm wide, 280 mm long, 0.04 mm thick, Pacol zipper bag, 4I, manufactured by Nippon Hightec Co., Ltd.) was cut off in advance to prepare a discharge bag for discharging mortar. The shape of the cutout was a right-angled isosceles triangle with a height of 15 mm and a base of 15 mm.

For each of the polymers of Examples 1 to 29 and Comparative Examples 1 and 2, mortar was kneaded and the above-mentioned flow test was carried out, and then the laminateability index was evaluated in the following manner.
(1) Mortar (flow test result: 196 mm to 204 mm) was poured into a discharge bag, and the weight before discharge was measured. Here, since there is a trade-off between fluidity and stackability, in the stackability evaluation test, the flow value was set to 196 mm to 204 mm for evaluation.
(2) The discharge bag was lifted and manually squeezed to discharge the material at a speed of one rotation per 10 seconds around the sides of a 100 mm square. The bag was rotated three times to stack three layers. The same discharge was repeated once more to produce a total of two stacks. After discharge was completed, the weight of the discharge bag was measured, and the discharge amount was calculated using the following formula:
Discharge amount (kg) = Weight of discharge bag before discharge (kg) - Weight of discharge bag after discharge (kg)
(3) When it was confirmed that the discharge amount was within the range of 0.45 kg or more and 0.55 kg or less, the height of the laminate was evaluated. The height (mm) was measured at eight points, namely, the four corners and the center of each side of the laminate, for a total of 16 height points (since there were two laminates), and the average was calculated.
(4) As an index of stackability, a stackability index calculated by the following formula was defined.
Lamination index = average height of 16 points (mm) ÷ discharge amount (kg)
Here, a higher value of the stackability index means higher stackability. The stackability index is preferably, for example, 30 or more, 35 or more, 40 or more, 42 or more, or 45 or more.

The lamination index for each example and comparative example evaluated according to the above is as shown in the right column of Table 1 above.

The results in Table 1 suggest that the use of the additives of the present invention can significantly improve the lamination properties of hydraulic compositions for additive manufacturing. It is also understood that n (the average number of moles of oxyalkylene groups added) of the structural unit (I) of the present invention is preferably 20 or more, 25 or more, 40 or more, 50 or more, 75 or more, 100 or more, 150 or more, 200 or more, or 250 or more, with a larger numerical range being preferable.

This application is based on Japanese Patent Application No. 2022-141353, filed on September 6, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

Claims (9)

The polymer includes a polymer having the following structural unit (I) and the following structural unit (II) :
The polymer contains 50.0 to 99.0 parts by weight of the structural unit (I) and 1.0 to 30.0 parts by weight of the structural unit (II) relative to 100 parts by weight of the polymer.

(In the structural unit (I), X is C═O or (CH ₂ ) _p [p is an integer of 0 to 5], R ⁴ O is an oxyalkylene group having 2 to 8 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number of 40 to 500, R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and the remaining R ¹ to R ³ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms.)

(In the structural unit (II), R ⁶ to R ⁸ are the same or different and represent a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a carboxyl group, and M represents a hydrogen atom or a cation species.) It contains a polymer having the following structural unit (I):
the polymer contains 50.0 to 99.0 parts by weight of the structural unit (I) relative to 100 parts by weight of the polymer;
The additive for a hydraulic composition for layered manufacturing, wherein the polymer further contains 1.0 to 30.0 parts by weight of a structural unit derived from an unsaturated monomer having at least one selected from the group consisting of a sulfonic acid group, a phosphoric acid group, and a salt group thereof, relative to 100 parts by weight of the polymer.

(In the structural unit (I), X is C═O or (CH ₂ ) _p [p is an integer from 0 to 5], and R ⁴ O is an oxyalkylene group having 2 to 8 carbon atoms, n is the average number of moles of oxyalkylene groups added and is a number from 15 to 500, and R ⁵ is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and the remaining R ¹ ~R ³ are the same or different and represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. The additive according to claim 1 or 2, wherein n is a number from 50 to 500. The additive according to claim 1 or 2 , wherein n is a number from 100 to 500. 3. The additive according to claim 1 , wherein X is (CH ₂ ) _p (p is an integer of 0 to 2). The additive according to claim 2 , wherein the polymer is a copolymer further comprising the following structural unit (II):

(In the structural unit (II), R ⁶ to R ⁸ are the same or different and represent a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a carboxyl group, and M represents a hydrogen atom or a cation species.) 3. The additive of claim 1 or 2, which is a lamination enhancer. A hydraulic composition for additive manufacturing, comprising the additive according to claim 1 or 2 . a step of mixing and stirring the hydraulic composition and the additive according to claim 1 or 2 ;
A method for producing a hydraulic composition for layered manufacturing, comprising: