Hydraulic composition

Abstract

To provide a hydraulic composition for laminate modeling having good extrudability from a nozzle and good self-supporting property after lamination.SOLUTION: There is provided a hydraulic composition which comprises (A) a water-soluble hydroxyalkyl alkyl cellulose, which is hydroxypropyl methyl cellulose and / or hydroxyethyl methyl cellulose, (B) a defoaming agent, (C) cement, (D) water and (E) diutan gum, wherein the degree of substitution (DS) of alkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose of the component (A) is 1.6 to 2.0, the 2 mass% aqueous solution viscosity of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 50 to 1000 mPa s and the amount added of the water of the component (D) is 25 to 70 pts.mass based on 100 pts,mass of the cement.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hydraulic composition suitable for additive manufacturing by 3D printing. [Background technology]

[0002] 3D printing is a method of creating a three-dimensional object by layering cross-sectional shapes based on three-dimensional data (additive manufacturing). There are four main 3D printing methods: binder jetting (a liquid binder is sprayed onto a powdered oil and selectively solidifies), directed energy deposition (the location of heat generation is controlled to selectively melt and bond materials), material jetting (droplets of material are sprayed, selectively deposited, and solidified), and material extrusion (a fluid material is extruded from a nozzle and solidified).

[0003] When using cement-based materials for 3D printing, the material extrusion method is the most suitable of these, but the properties required of the material in this case are ease of extrusion from the nozzle and self-supporting ability after layering.Since these are contradictory properties, it has been difficult to achieve both.

[0004] In order to solve this problem, Patent Publication No. 2020-105023 (Patent Document 1) specifies the relationship between the content of cellulose-based thickener and silica fume, thereby achieving both extrudability and self-supporting properties after lamination. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-105023 Summary of the Invention [Problem to be solved by the invention]

[0006] However, Patent Document 1 specifies the viscosity of a 1% by mass aqueous solution of a cellulose-based thickener for each shear rate, but hydraulic compositions containing silica fume become very thixotropic, so the properties of the cellulose-based thickener are not utilized, and there are cases where the desired effects, such as poor dischargeability, are not obtained.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a hydraulic composition that is suitable for material extrusion type 3D printing, has good extrudability from a nozzle, and exhibits good self-supporting properties after lamination. [Means for solving the problem]

[0008] As a result of intensive research conducted by the present inventors to achieve the above object, they discovered that by using a water-soluble hydroxyalkyl alkyl cellulose having a specific degree of substitution (DS) and aqueous solution viscosity, an antifoaming agent, cement, water, and diutan gum, the pressure required to extrude the resulting hydraulic composition from a nozzle is low and the self-supporting properties after lamination are good, which led to the completion of the present invention.

[0009] Accordingly, the present invention provides the following hydraulic composition. 1. A hydraulic composition comprising (A) a water-soluble hydroxyalkyl alkyl cellulose which is at least one selected from hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose, (B) an antifoaming agent, (C) cement, (D) water, and (E) diutan gum, the degree of substitution (DS) of the alkoxy group of the water-soluble hydroxyalkyl alkyl cellulose of component (A) is 1.6 to 2.0, and the viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 50 to 1000 mPa s; The amount of the water-soluble hydroxyalkyl alkyl cellulose added as component (A) is 0.1 to 0.6 parts by mass relative to 100 parts by mass of the cement, and the amount of diutan gum added as component (E) is 0.1 to 0.3 parts by mass relative to 100 parts by mass of the cement, A hydraulic composition in which the amount of water added as component (D) is 25 to 70 parts by mass per 100 parts by mass of the cement. 2. The amount of water-soluble hydroxyalkyl alkyl cellulose added as component (A) is determined based on 100 parts by mass of cement.0.2 ~ 0.5 1. The hydraulic composition according to 1, wherein the content is parts by mass. 3. The amount of diutan gum added as component (E) is based on 100 parts by mass of cement. 0.1 ~ 0.2 3. The hydraulic composition according to 1 or 2, wherein the content is parts by mass. 4. 3. The hydraulic composition according to 1 or 2, wherein the water-soluble hydroxyalkyl alkyl cellulose of component (A) is hydroxypropyl methyl cellulose, and the thermal gelation temperature thereof is 55 to 65°C. 5. 3. The hydraulic composition according to 1 or 2, wherein the water-soluble hydroxyalkyl alkyl cellulose of component (A) is hydroxyethyl methyl cellulose, and the thermal gelation temperature thereof is 68 to 83°C. 6. 3. The hydraulic composition according to 1 or 2, which is for additive manufacturing. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a hydraulic composition that is a cement-based material suitable for 3D printing using a material extrusion method, has good extrudability from a nozzle, and also has good self-supporting properties after lamination. DETAILED DESCRIPTION OF THE INVENTION

[0011] The hydraulic composition according to the present invention will be described below. The hydraulic composition according to the present invention is a hydraulic composition comprising (A) a water-soluble hydroxyalkyl alkyl cellulose which is at least one selected from hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose, (B) an antifoaming agent, (C) cement, (D) water, and (E) diutan gum, wherein the degree of substitution (DS) of the alkoxy group of the water-soluble hydroxyalkyl alkyl cellulose of component (A) is 1.6 to 2.0, and the viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 50 to 1000 mPa·s, and the amount of water added as component (D) is 25 to 70 parts by mass per 100 parts by mass of the cement.

[0012] The hydraulic composition according to the present invention is a hydraulic composition containing a water-soluble hydroxyalkyl alkyl cellulose, an antifoaming agent, cement, water and diutan gum.

[0013] (Component (A)) The water-soluble hydroxyalkyl alkyl cellulose used in the present invention is at least one selected from hydroxypropyl methyl cellulose (HPMC) and hydroxyethyl methyl cellulose (HEMC).

[0014] The degree of substitution (DS) of alkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose used in the present invention is 1.6 to 2.0, preferably 1.6 to 1.95, more preferably 1.6 to 1.93, and even more preferably 1.65 to 1.93, from the viewpoint of both extrudability from a nozzle and self-supporting properties after lamination. The molar substitution (MS) of hydroxyalkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose is preferably 0.05 to 0.6, more preferably 0.1 to 0.5, and even more preferably 0.15 to 0.4, from the viewpoint of solubility during use in summer.

[0015] The DS of the alkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose represents the degree of substitution, and refers to the average number of alkoxy groups per unit of anhydroglucose. The MS of the hydroxyalkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose represents the molar substitution, and refers to the average number of moles of hydroxyalkoxy groups per mole of anhydroglucose. The DS of the alkoxy groups and the MS of the hydroxyalkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose can be determined by converting values ​​measured by the substitution degree analysis method for hypromellose (hydroxypropyl methylcellulose) described in the 18th Edition of the Japanese Pharmacopoeia.

[0016] The viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose used in the present invention at 20°C is 50 to 1,000 mPa·s, preferably 100 to 800 mPa·s, more preferably 200 to 700 mPa·s, and even more preferably 300 to 600 mPa·s, from the viewpoint of achieving both extrudability from a nozzle and self-supporting properties after lamination. The viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C can be measured using a B-type viscometer.

[0017] Here, the water-soluble hydroxyalkyl alkyl cellulose of component (A) has a degree of substitution (DS) of the alkoxy groups of 1.6 to 2.0, and the viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 50 to 1000 mPa·s, preferably has a degree of substitution (DS) of 1.6 to 1.95, and the viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 100 to 800 mPa·s, and more preferably has a degree of substitution (DS) of 1.65 to 1.93, and the viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 300 to 600 mPa·s.

[0018] In addition, a suitable combination of the degree of substitution of alkoxy groups (DS), the number of moles of hydroxyalkoxy groups (MS) and the viscosity of a 2% by mass aqueous solution at 20°C in the water-soluble hydroxyalkyl alkyl cellulose is, when component (A) is hydroxypropyl methyl cellulose, preferably the degree of substitution of methoxy groups (DS): 1.6 to 2.0, the number of moles of hydroxypropoxy groups (MS): 0.05 to 0.6, and the viscosity of a 2% by mass aqueous solution at 20°C: 5. The degree of substitution with methoxy groups (DS): 0 to 1000 mPa·s, more preferably the degree of substitution with methoxy groups (DS): 1.6 to 1.95, the molar substitution number of hydroxypropoxy groups (MS): 0.1 to 0.5, and the viscosity of a 2% by mass aqueous solution at 20°C: 100 to 800 mPa·s, and even more preferably the degree of substitution with methoxy groups (DS): 1.65 to 1.93, the molar substitution number of hydroxypropoxy groups (MS): 0.15 to 0.4, and the viscosity of a 2% by mass aqueous solution at 20°C: 300 to 600 mPa·s. Furthermore, when component (A) is hydroxyethyl methylcellulose, the degree of substitution with methoxy groups (DS): is preferably 1.6 to 2.0, the number of moles of substitution with hydroxyethoxy groups (MS): is 0.05 to 0.6, and the viscosity of a 2% by mass aqueous solution at 20°C is preferably 50 to 1000 mPa·s, more preferably the degree of substitution with methoxy groups (DS): is 1.6 to 1.95, the number of moles of substitution with hydroxyethoxy groups (MS): is 0.1 to 0.5, and the viscosity of a 2% by mass aqueous solution at 20°C is 100 to 800 mPa·s, and even more preferably the degree of substitution with methoxy groups (DS): is 1.65 to 1.93, the number of moles of substitution with hydroxyethoxy groups (MS): is 0.15 to 0.4, and the viscosity of a 2% by mass aqueous solution at 20°C is 300 to 600 mPa·s.

[0019] From the viewpoint of solubility during summer use, the thermal gelation temperature of the water-soluble hydroxyalkyl alkyl cellulose used in the present invention is preferably 55 to 65°C, more preferably 55 to 64°C, and even more preferably 55 to 63°C when component (A) is hydroxypropyl methylcellulose, and is preferably 68 to 83°C, more preferably 68 to 81°C, and even more preferably 68 to 80°C when component (A) is hydroxyethyl methylcellulose.

[0020] The thermal gelation temperature of water-soluble hydroxyalkyl alkyl cellulose can be measured using a torsional vibration viscometer. When a water-soluble hydroxyalkyl alkyl cellulose prepared to a concentration of 2% by mass is heated from 20°C at a rate of 1°C / min, the temperature at which the viscosity begins to decrease is defined as the thermal gelation temperature.

[0021] The amount of water-soluble hydroxyalkyl alkyl cellulose added as component (A) is preferably 0.1 to 0.6 parts by mass, more preferably 0.15 to 0.55 parts by mass, and even more preferably 0.2 to 0.5 parts by mass per 100 parts by mass of cement as component (C), from the viewpoint of achieving both extrudability from a nozzle and self-supporting properties after lamination.

[0022] ((B) component) The antifoaming agent has the function of suppressing bubbles entrained by the water-soluble hydroxyalkyl alkyl cellulose. If there are a large number of bubbles, there are problems such as a decrease in strength and poor self-supporting ability after lamination. In the present invention, the antifoaming agent used may be an oxyalkylene-based, silicone-based, alcohol-based, mineral oil-based, fatty acid-based, fatty acid ester-based, or the like.

[0023] Examples of oxyalkylene antifoaming agents include polyoxyalkylenes such as (poly)oxyethylene (poly)oxypropylene adducts; (poly)oxyalkylene alkyl ethers such as diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene 2-ethylhexyl ether, and oxyethylene oxypropylene adducts to higher alcohols having 8 or more carbon atoms or secondary alcohols having 12 to 14 carbon atoms; (poly)oxyalkylene (alkyl)aryl ethers such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether; alkylene aryl ethers to acetylene alcohols such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, and 3-methyl-1-butyn-3-ol; (poly)oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, and ethylene glycol distearate; (poly)oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan trioleate; (poly)oxyalkylene alkyl (aryl) ether sulfate salts such as polyoxypropylene methyl ether sodium sulfate and polyoxyethylene dodecylphenol ether sodium sulfate; (poly)oxyalkylene alkyl phosphates such as (poly)oxyethylene stearyl phosphate; (poly)oxyalkylene alkyl amines such as polyoxyethylene laurylamine; and polyoxyalkylene amides.

[0024] Examples of silicone-based antifoaming agents include dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil, and the like. Examples of alcohol-based antifoaming agents include octyl alcohol, 2-ethylhexyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols, and the like. Examples of mineral oil-based defoaming agents include kerosene and liquid paraffin. Examples of fatty acid antifoaming agents include oleic acid, stearic acid, and alkylene oxide adducts thereof. Examples of fatty acid ester-based antifoaming agents include glycerin monoricinoleate, alkenyl succinic acid derivatives, sorbitol monolaurate, sorbitol trioleate, and natural waxes. In the present invention, it is preferable to use an oxyalkylene-based defoaming agent from the viewpoint of defoaming performance.

[0025] The amount of the antifoaming agent (B) added is preferably 1 to 30 parts by mass, more preferably 3 to 29 parts by mass, and even more preferably 5 to 28 parts by mass relative to 100 parts by mass of water-soluble hydroxyalkyl alkyl cellulose, from the viewpoints of preventing deterioration of self-supporting ability after lamination due to bubbles entrained during preparation of the hydraulic composition and of improving the strength of the hydraulic composition.

[0026] ((C) component) The cement that can be used in the present invention includes various cements such as ordinary Portland cement, high-early-strength Portland cement, moderate-heat Portland cement, blast-furnace cement, silica cement, fly ash cement, alumina cement, and ultra-high-early-strength Portland cement.

[0027] ((D) component) The water used in the present invention may be tap water, seawater, or the like, but tap water is preferred from the viewpoint of preventing salt damage. The amount of water added as component (D) is 25 to 70 parts by mass, preferably 28 to 67 parts by mass, and more preferably 30 to 65 parts by mass, per 100 parts by mass of cement. The amount of water used in the hydraulic composition is preferably 15 to 70% by mass, more preferably 16 to 65% by mass, and even more preferably 17 to 60% by mass, based on the total amount of cement and the fine aggregate described below, from the viewpoint of achieving both extrudability from a nozzle and self-supporting properties after lamination.

[0028] ((E) component) In the present invention, diutan gum is contained as component (E). The amount of diutan gum added as component (E) is preferably 0.01 to 0.3 parts by mass, more preferably 0.02 to 0.25 parts by mass, and even more preferably 0.02 to 0.2 parts by mass per 100 parts by mass of cement, from the viewpoint of achieving both ease of extrusion from a nozzle and self-supporting properties after lamination.

[0029] (Other ingredients) The hydraulic composition of the present invention can further contain fine aggregate. Suitable fine aggregates include river sand, mountain sand, sea sand, land sand, and silica sand, which are commonly used in ready-mixed concrete production and as fine aggregate for plastering. The particle size is preferably 0.075 to 5 mm, more preferably 0.075 to 2 mm, and even more preferably 0.075 to 1 mm.

[0030] The amount of fine aggregate used is preferably 15 to 85 parts by mass, more preferably 20 to 80 parts by mass, and even more preferably 25 to 75 parts by mass, per 100 parts by mass of the total amount of cement and fine aggregate.

[0031] Furthermore, a portion of the fine aggregate may be replaced with an inorganic or organic filler. In this case, examples of inorganic fillers include fly ash, blast furnace slag, talc, calcium carbonate, silica fume, marble powder (limestone powder), perlite, and shirasu balloons. Examples of organic fillers include expanded polystyrene beads and crushed ethylene vinyl alcohol foam. Inorganic or organic fillers with a particle size of 5 mm or less are typically used, and these are preferably used.

[0032] In the present invention, water-soluble polymeric substances other than those mentioned above can be used to further improve both the extrudability from the nozzle and the self-supporting properties after lamination. Examples of water-soluble polymeric substances include synthetic polymeric substances such as polyacrylamide, polyethylene glycol, and polyvinyl alcohol, as well as naturally occurring polymeric substances such as pectin, gelatin, casein, welan gum, xanthan gum, gellan gum, locust bean gum, and guar gum. The amount of water-soluble polymeric substance added is preferably 0.01 to 1.0 parts by mass, more preferably 0.05 to 0.8 parts by mass, and even more preferably 0.1 to 0.6 parts by mass per 100 parts by mass of cement.

[0033] In the hydraulic composition of the present invention, known water-reducing agents, setting retarders, setting accelerators, short fibers, expansive agents, shrinkage-reducing agents, etc. can be used as needed within the range that does not impair the effects of the present invention.

[0034] Examples of water-reducing agents include polycarboxylic acid-based agents such as polycarboxylic acid ethers, complexes of polycarboxylic acid ethers and crosslinked polymers, complexes of polycarboxylic acid ethers and oriented polymers, complexes of polycarboxylic acid ethers and highly modified polymers, polyethercarboxylic acid polymer compounds, maleic acid copolymers, maleic acid ester copolymers, maleic acid derivative copolymers, carboxyl group-containing polyethers, polycarboxylic acid group-containing multicomponent polymers with terminal sulfonic groups, polycarboxylic acid graft copolymers, polycarboxylic acid compounds, and polycarboxylic acid ether polymers. Examples of melamine-based agents include melamine sulfonic acid formalin condensates, melamine sulfonate condensates, and melamine sulfonate polyol condensates. Examples of lignin-based agents include lignin sulfonates and their derivatives. In the present invention, it is preferable to use a polycarboxylic acid-based water-reducing agent in terms of water-reducing effect, fluidity and fluidity retention. The amount of the water reducing agent added is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of cement.

[0035] Examples of the setting retarder include oxycarboxylic acids such as gluconic acid, citric acid, glucoheptone, etc., or inorganic salts thereof such as sodium, potassium, calcium, magnesium, ammonium, etc., sugars such as glucose, fructose, galactose, saccharose, xylose, avitose, lipose, oligosaccharides, dextran, etc., boric acid, etc. The amount of setting retarder added is preferably 0.005 to 10 parts by mass per 100 parts by mass of cement.

[0036] Setting accelerators are broadly classified into inorganic compounds and organic compounds. Examples of inorganic compounds include chlorides such as calcium chloride and potassium chloride, nitrites such as sodium nitrite and calcium nitrite, nitrates such as sodium nitrate and calcium nitrate, sulfates such as calcium sulfate, sodium sulfate, and alum, thiocyanates such as sodium thiocyanate, hydroxides such as sodium hydroxide and potassium hydroxide, carbonates such as calcium carbonate, sodium carbonate, and lithium carbonate, and alumina compounds such as water glass, aluminum hydroxide, and aluminum oxide. Examples of organic compounds include amines such as diethanolamine and triethanolamine, calcium salts of organic acids such as calcium formate and calcium acetate, and maleic anhydride. The amount of the setting accelerator added is preferably 0.005 to 10 parts by mass per 100 parts by mass of cement.

[0037] Examples of short fibers include polypropylene fibers, vinylon fibers, acrylic fibers, glass fibers, steel fibers, basalt fibers, etc. The amount of short fibers added is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, and even more preferably 0.3 to 3 parts by mass, per 100 parts by mass of cement.

[0038] Examples of the expansive material include ettringite-based expansive materials, lime-based expansive materials, and ettringite-lime composite expansive materials. The amount of the expansive material added is preferably 0.5 to 30 parts by mass, more preferably 1 to 30 parts by mass, and even more preferably 3 to 25 parts by mass, per 100 parts by mass of cement.

[0039] Examples of shrinkage reducing agents include lower or higher alcohol alkylene oxide adducts, glycol ether derivatives, polyether derivatives, etc. The amount of shrinkage reducing agent added is preferably 0.1 to 0.5 parts by mass, more preferably 0.15 to 0.45 parts by mass, and even more preferably 0.2 to 0.4 parts by mass, per 100 parts by mass of cement.

[0040] The hydraulic composition of the present invention as described above has good extrudability from a nozzle and also has good self-supporting properties after lamination, making it suitable for additive manufacturing, particularly for 3D printing using a material extrusion method. [Example]

[0041] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, the viscosity values ​​are measured at 20°C using a B-type rotational viscometer. The thermal gelation temperature was determined as the temperature at which the viscosity, measured using a torsional vibration viscometer, began to decrease when a water-soluble hydroxyalkyl alkyl cellulose (CE) prepared to a concentration of 2% by mass was heated from 20°C at a rate of 1°C / min.

[0042] [Example 1~ 9 , Comparative Examples 1 to 3] <Materials used> (1) Cement (C): Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation) (2) Water: Tap water (3) Water-soluble hydroxyalkyl alkyl cellulose (CE): Sample details are shown in Table 1 (4) Diutan Gum (DG): KELCO-VIS DG (manufactured by CP KELCO) (5) Defoamer: SN Deformer 14HP (manufactured by San Nopco Co., Ltd.)

[0043] [Table 1] HPMC: Hydroxypropyl methylcellulose HEMC: Hydroxyethylmethylcellulose

[0044] <Preparation of hydraulic composition> Using a mortar mixer conforming to JIS R 5201, the materials were placed in a mixing bowl in the amounts shown in Table 2 and mixed for 60 seconds at low speed (rotational movement 140 rpm, planetary movement 60 rpm). Next, mixing was continued for 90 seconds at high speed (rotational movement 290 rpm, planetary movement 120 rpm) to obtain a hydraulic composition. The material temperature was adjusted so that the temperature after mixing was within 20±3°C. CE, DG, and antifoaming agent were mixed with cement in advance and then added to the mixing bowl together with the cement.

[0045] [Table 2]

[0046] The shear stress of the obtained hydraulic composition was measured against the shear rate under the following conditions using a rheometer (HAAKE MARS 60 manufactured by Thermo Fisher Scientific). Measurement jig: 20mm bob-type rotor (CC20) Shear rate: increase 0.1s -1 From 100s -1 Up (120 seconds), Down 100 seconds -1 to 0.1 seconds -1 Until (120 seconds) Gap: 4.2mm ·Temperature: 20℃

[0047] The evaluation items were yield value, hysteresis loop (HL) area, and HL area / yield value, which were calculated using the following method. Yield value (Y): The yield value was calculated by fitting a descending curve obtained by decreasing the shear rate (horizontal axis: shear rate, vertical axis: shear stress) to a Casson plot. A yield value of less than 15 Pa was evaluated as having excellent dischargeability. ·HL area (A HL) The difference in area between the ascending curve (horizontal axis: shear rate, vertical axis: shear stress) and the descending curve obtained when the shear rate was increased, i.e., the area of ​​the hysteresis loop formed by the ascending curve and the descending curve, was evaluated, and when the shear rate was 1000 Pa / s or higher, it was evaluated as having excellent thixotropy. HL area / yield value (A HL / Y): The HL area divided by the yield value, and -1 In the above cases, it was evaluated that the composition had both ejection properties and thixotropy. The test results are shown in Table 3.

[0048] [Table 3]

[0049] Examples 1 to 3 were prepared using CE in which "the degree of substitution (DS) of the alkoxy group of the water-soluble hydroxyalkyl alkyl cellulose of component (A) is 1.6 to 2.0, and the viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 50 to 1000 mPa s" and "the amount of water added as component (D) is 25 to 70 parts by mass relative to 100 parts by mass of the cement." 9 The criteria for "yield value," "HL area," and "HL area / yield value" were all met. On the other hand, under the conditions of Comparative Example 1, although the "yield value" and "HL area" met the criteria, the "HL area / yield value" was low, resulting in a failure to achieve both ejection properties and thixotropy. Furthermore, Comparative Example 2 had a high "yield value" and poor ejection properties, while Comparative Example 3 had a low "HL area" and poor thixotropy. In addition, both Comparative Examples 2 and 3 had results in which the "HL area / yield value" did not meet the criteria.

[0050] Although the present invention has been described using the above-mentioned embodiment, the present invention is not limited to this embodiment, and can be modified within the scope of what a person skilled in the art can conceive, such as other embodiments, additions, changes, deletions, etc., and any aspect is included in the scope of the present invention as long as it achieves the effects of the present invention.

Claims

1. A hydraulic composition comprising (A) at least one water-soluble hydroxyalkyl alkyl cellulose selected from hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose, (B) an antifoaming agent, (C) cement, (D) water, and (E) diutan gum, the degree of substitution (DS) of the alkoxy group of the water-soluble hydroxyalkyl alkyl cellulose of component (A) is 1.6 to 2.0, and the viscosity of a 2% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C is 50 to 1000 mPa s; A hydraulic composition in which the amount of water-soluble hydroxyalkyl alkyl cellulose added as component (A) is 0.1 to 0.6 parts by mass relative to 100 parts by mass of the cement, the amount of diutan gum added as component (E) is 0.1 to 0.3 parts by mass relative to 100 parts by mass of the cement, and the amount of water added as component (D) is 25 to 70 parts by mass relative to 100 parts by mass of the cement.

2. 2. The hydraulic composition according to claim 1, wherein the amount of the water-soluble hydroxyalkyl alkyl cellulose added as component (A) is 0.2 to 0.5 parts by mass per 100 parts by mass of cement.

3. 3. The hydraulic composition according to claim 1, wherein the amount of diutan gum added as component (E) is 0.1 to 0.2 parts by mass per 100 parts by mass of cement.

4. 3. The hydraulic composition according to claim 1, wherein the water-soluble hydroxyalkyl alkyl cellulose of component (A) is hydroxypropyl methyl cellulose, and the thermal gelling temperature thereof is 55 to 65°C.

5. 3. The hydraulic composition according to claim 1, wherein the water-soluble hydroxyalkyl alkyl cellulose of component (A) is hydroxyethyl methyl cellulose, and the thermal gelling temperature thereof is 68 to 83°C.

6. The hydraulic composition according to claim 1 or 2, which is used for layered manufacturing.

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