JP2014012616A - Admixture for extrusion molding of cement, and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an admixture for extrusion molding of cement, used for extrusion molding of cement and capable of solving both problems of extrudability and quality of an extrusion molding of cement in a case of manufacturing the extrusion molding of cement.SOLUTION: An admixture for extrusion molding of cement contains a cellulose-based binder and an anionic surfactant and is an admixture used for an extrusion molding of cement. The cellulose-based binder contains at least one specific kind and a viscosity of 1 wt% solution is 6,000 to 30,000 mPa s. The anionic surfactant contains at least one kind selected from a group consisting of sodium alkyl sulfate, sodium α-olefin sulfonate and sodium alkylbenzene sulfonate. A content ratio of the cellulose-based binder to anionic surfactant is 99.8:0.2 to 97.0:3.0.

Description

  The present invention relates to an admixture for cement extrusion and uses.

Conventionally, cement extrudates are obtained by adding water to a cement mixture containing 1) hydraulic materials such as ordinary Portland cement and fine aggregates such as silica sand, as well as reinforcing fibers and lightweight aggregates used as necessary. A mortar that is a clay-like highly viscous substance is prepared, and then 2) the obtained mortar is formed into a desired shape such as a flat plate or a hollow shape using a vacuum extrusion molding machine.
When producing a cement extrusion, there is often a problem that the extrusion pressure is high and the extrusion speed becomes unstable. Also, for cement extruded products obtained by extrusion molding, the surface of the molded product due to occurrence of meandering, blisters, cracks, cracks, irregularities, etc., often due to irregularities in the discharge state of the molded product from the mold. There was a problem that the state deteriorated and the dimensional accuracy was low. In order to solve such problems of extrudability at the time of production and quality of a molded product, conventionally, an excessive amount of a cellulose-based binder has been used. However, since hydraulic materials and fine aggregates, which are the main components contained in mortar, are inorganic components, it goes without saying that it is preferable to avoid blending cellulose-based binders that are not inorganic components. Doing this was an economic disadvantage as it went against cost reductions.

In order to improve the problem of extrudability, for example, techniques shown in the following Patent Documents 1 to 4 are known.
In Patent Document 1, it is said that by adding a liquid material containing a surfactant, the fluidity of the mortar is improved, thereby contributing to a decrease in extrusion pressure and speed stability. However, in actual extrusion, the pressure drop was insufficient, and the quality such as surface properties was very inferior.

In Patent Document 2, when a cement composition containing a modified polycarboxylic acid is extruded, the cement or the like is dispersed with the modified polycarboxylic acid to reduce the pressure required for the extrusion and to lower the extrusion pressure. Moreover, even if the amount of asbestos is reduced, the moldability of the cement composition can be maintained at a high level and the strength of the hardened cement can be maintained, and the addition amount of the cellulose binder is further reduced. Yes. However, polycarboxylic acid-based AE agents (air entraining agents) and water-reducing agents are commonly referred to, but the improvement in fluidity due to these agents is always accompanied by the problem of deterioration in the quality of extruded products due to air entrainment. Advanced defoaming technology is required. Moreover, about the reduction | decrease of a cellulose binder, the reduction effect is not recognized now at the time of asbestos-free use.
Patent Document 3 proposes a reduction in extrusion pressure and a reduction in fluctuation by equipment improvement by adjusting a flow path in a mold in accordance with a change in mortar fluidity. However, there is no contribution to the quality of the extruded product, and the introduction of the variable mold into the equipment and the cost of maintenance are difficult, so it is difficult to say that the method is widely used at present.

In patent document 4, it is said that even if the addition amount of a thickener is reduced by extrusion molding using hydrophilic resin fine particles, it can be molded at an economical discharge pressure and extrusion speed. However, the water retentivity and shape retention of the hydrophilic fine particles themselves are inferior to those of the cellulose binder, and there is a problem that the quality of the extruded product is lowered. In addition, hydrophilic fine particles themselves are required to be pulverized when used in the extruded product industry. However, since they become more expensive materials than cellulose binders in pulverization, hydrophilic resin particles and cellulose binders. Even when is used as a thickener, the present technology is not effective because the amount of addition of the thickener is not reduced.
Next, in order to improve the quality problem, for example, techniques shown in the following Patent Documents 5 to 7 are known.

In Patent Document 5, it is said that necessary moldability and strength can be obtained with a small addition amount by selectively using a cellulose ether binder having a high thermal gelation temperature. However, cracks can be reduced in the cement-extruded product as a quality, but the surface condition, which is another important quality, and an improvement in extrudability cannot be obtained.
In Patent Document 6, it is said that by selectively using a high-viscosity cellulose ether binder, a cement extruded product with improved shape retention can be efficiently produced with a small addition amount. Certainly, even if the amount of cellulose ether binder added is reduced, the performance of maintaining the shape and dimensions of the extruded product as it exits the mold will be good, but the other important quality is the surface. The improvement in extrudability such as the state and extrusion pressure / extrusion speed cannot be obtained.

Patent Document 7 describes a binder for a hydraulic composition characterized by comprising a long-chain alkylbenzenesulfonic acid or a neutralized salt thereof in combination with a water-soluble cellulose ether. Although improvement in the quality of cement extruded products can be achieved by improving the fluidity of inorganic particles, mortar hardness is softened due to deterioration in quality such as dimensional stability due to bubble entrainment, and significant plasticization, causing problems in extrudability. is there.
As described above, it is considered that none of the problems of extrudability in the production of a cement extruded product and the quality of the cement extruded product are solved while considering the economy.

Japanese Patent Laid-Open No. 03-215335 JP 06-182749 A JP-A-10-156818 Japanese Patent Laid-Open No. 10-081551 JP 05-085799 A Japanese Patent Publication No. 07-115908 JP 2001-270751 A

  It is an object of the present invention to be used in cement extrusion, and to be used for cement extrusion molding, which can solve both the problem of extrudability when producing a cement extrusion and the quality of the resulting cement extrusion. It is to provide an agent, a mixture for cement extrusion molding using the same, a method for producing the mixture, and a cement extrusion molding.

In order to solve the above-mentioned problems, the present inventors have intensively studied, and as a result, a specific cellulose-based binder and an anionic surfactant are used in combination, and a cement extrusion molding admixture adjusted to a specific ratio is used. The knowledge of solving the above problems was obtained by performing cement extrusion, and the present invention was completed.
The admixture for cement extrusion of the present invention comprises a cement, a cellulosic binder and an anionic surfactant, and is a mixture for cement extrusion used for cement extrusion,
The cellulose binder contains at least one selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkylalkyl cellulose, and the viscosity of a 1% by weight aqueous solution of the cellulose binder is 6000 to 30000 mPa · s (B-type viscosity). The anionic surfactant contains at least one selected from the group consisting of sodium alkyl sulfate, sodium α-olefin sulfonate and sodium alkylbenzene sulfonate, and the cellulose binder and anionic The weight ratio of the surfactant (cellulosic binder / anionic surfactant) is 99.8 / 0.2 to 97.0 / 3.0.

The anionic surfactant is preferably a solid at 20 ° C.
The cement extrusion mixture of the present invention comprises a cement, a cellulosic binder and an anionic surfactant, and is a cement extrusion mixture used for cement extrusion,

This is a mixture obtained by blending 0.3 to 3 parts by weight of the above-mentioned admixture for cement extrusion as the cellulose-based binder and an anionic surfactant with respect to 100 parts by weight of the inorganic material essential for the cement.
The blending is preferably carried out after 24 hours or more have elapsed since the cement extrusion molding admixture was prepared.

  The method for producing a cement extrusion molding mixture of the present invention comprises at least one selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose, and the viscosity of a 1% aqueous solution is 6000 to 30000 mPa · s (B type). A cellulose binder comprising a viscometer, a measurement temperature of 20 ° C., and an anionic surfactant containing at least one selected from the group consisting of sodium alkyl sulfate, sodium α-olefin sulfonate, and sodium alkylbenzene sulfonate. Mixing so that the weight ratio of the binder and the anionic surfactant (cellulosic binder / anionic surfactant) is 99.8 / 0.2 to 97.0 / 3.0 and mixing for cement extrusion Manufacturing agent Step 1 for preparing a cement extrusion molding mixture by blending 0.3 to 3.0 parts by weight of the admixture for cement extrusion with 100 parts by weight of an inorganic material essential for cement. It is a manufacturing method including.

The anionic surfactant is preferably solid at 20 ° C., and the step 2 is preferably performed at least 24 hours after the step 1.
The cement extrusion molded product of the present invention is a molded product obtained by blending water into the above-mentioned cement extrusion molding mixture and / or the cement extrusion molding mixture obtained by the above production method and extruding the resulting mortar. is there.

The admixture for cement extrusion of the present invention can solve both of the problem of extrudability when producing a cement extrusion and the quality of the resulting cement extrusion. In particular, handling is easy when the anionic surfactant is a solid.
The cement extrusion molding mixture of the present invention can solve both the problem of extrudability when producing a cement extrusion and the problem of the quality of the resulting cement extrusion. In particular, when the anionic surfactant is solid at 20 ° C., handling is easy. Moreover, when it mix | blends with cement after 24 hours or more have passed since preparation of the admixture for cement extrusion molding, when manufacturing a cement extrusion molding, the compounding quantity of the admixture for cement extrusion molding can be reduced.

In the method for producing a cement extrusion molding mixture of the present invention, a cement extrusion molding mixture that can solve both of the problem of extrudability when producing a cement extrusion molding and the problem of the quality of the resulting cement extrusion molding. Can be easily produced. In particular, when the anionic surfactant is solid at 20 ° C., handling is easy. Moreover, in this manufacturing method, the blending amount of the admixture for cement extrusion molding is reduced when the cement extrusion molding is manufactured by performing the step 2 of manufacturing the cement extrusion molding mixture at least 24 hours after the step 1. Can do.
The cement extrudate of the present invention can solve both the problem of extrudability when producing it and the quality of the resulting cement extrudate.

[Admixture for cement extrusion and its production]
The admixture for cement extrusion according to the present invention includes a cellulosic binder and an anionic surfactant, and is an admixture used for cement extrusion.
Cellulosic binder is the main component of admixture for cement extrusion. Cement extrusion molding obtained by extruding mortar by imparting plasticity and water retention to mortar obtained using a mixture for cement extrusion described later. It is a component that gives good extrudability and high quality to the product.

The cellulosic binder imparts excellent plasticity and water retention to the mortar obtained from the admixture for cement extrusion and the mixture for cement extrusion described later, and is excellent for extrusion of cement obtained by extruding the mortar. It is a component that can give high quality and high quality. Cellulosic binders are usually solid and powder.
Examples of the cellulose binder include alkyl celluloses such as methyl cellulose; hydroxyalkyl celluloses such as hydroxyethyl cellulose and hydroxypropyl cellulose; hydroxyalkylalkyl celluloses such as hydroxyethyl methyl cellulose and hydroxypropyl methyl cellulose. More than one species may be used in combination.

The viscosity of a 1% by weight aqueous solution of a cellulose binder (measured with a B-type viscometer, measurement temperature 20 ° C.) is 6000 to 30000 mPa · s, preferably 7000 to 25000 mPa · s, more preferably 8000 to 20000 mPa · s. s, particularly preferably 9000 to 15000 mPa · s. When the viscosity is within this range, the shape retention of a cement extruded product obtained by extruding mortar becomes high. The shape-retaining property as used in the present invention refers to the ability to maintain the shape of the extruded product discharged from the mold, and is greatly related to the quality. If the viscosity of the 1% aqueous solution of the cellulose binder is less than 6000 mPa · s, the shape retention may be insufficient. On the other hand, if the viscosity of a 1% aqueous solution of a cellulose-based binder exceeds 30000 mPa · s, solubility in water becomes difficult, and water retention is inferior to low-viscosity products, so that the lubrication effect during extrusion becomes insufficient. Good extrudability may not be obtained.
An anionic surfactant is a component which accelerates | stimulates dissolving a cellulosic binder in water. Conventionally, only about 50 to 80% of the cellulosic binder is dissolved at the time of preparing the mortar, and therefore, the cellulosic binder has been used more than necessary. However, by using an anionic surfactant, the cellulosic binder can be dissolved to a state almost completely dissolved, and thereby good quality and extrudability can be obtained even if the cellulosic binder is low blended. It becomes like this.

Since an anionic surfactant is easy to handle and easily disperses uniformly with a cellulose-based binder or cement, the appearance at 20 ° C. is preferably solid, and more preferably powder. In addition, when the anionic surfactant is a powder having the same particle size as that of the cellulose-based binder powder, the cellulose-based binder and the surfactant are not powdered and are not separated and unevenly distributed. It is particularly preferred because it gives a cement admixture for cement extrusion.
Examples of the anionic surfactant include sodium alkyl sulfate, sodium α-olefin sulfonate, sodium alkyl benzene sulfonate, and the like, and one or more of them may be used in combination.

Although there is no limitation in particular about carbon number of the alkyl in alkyl sulfate sodium, Preferably it is 8-18, More preferably, it is 10-14, Most preferably, it is 11-13. If the alkyl has less than 8 carbon atoms, the compatibility with the cellulose-based binder may decrease. On the other hand, when the carbon number of alkyl exceeds 18, the dissolution promoting effect of the cellulose binder may be lowered.
Although there is no limitation in particular about carbon number of the alpha olefin in alpha olefin sulfonate sodium, Preferably it is 10-20, More preferably, it is 14-18, Most preferably, it is 15-17. If the α-olefin has less than 10 carbon atoms, the compatibility with the cellulose binder may be reduced. On the other hand, when the number of carbon atoms of the α-olefin exceeds 20, the dissolution promoting effect of the cellulose binder may be lowered.

Although there is no limitation in particular about the carbon number of the alkyl in alkylbenzene sulfonate sodium, Preferably it is 8-18, More preferably, it is 10-14, Most preferably, it is 11-13. If the alkyl has less than 8 carbon atoms, the compatibility with the cellulose-based binder may decrease. On the other hand, when the carbon number of alkyl exceeds 18, the dissolution promoting effect of the cellulose binder may be lowered.
The weight ratio of the cellulose binder and the anionic surfactant (cellulose binder / anionic surfactant) is usually 99.8 / 0.2 to 97.0 / 3.0, preferably 99.6 / 0.4 to 97.2 / 2.8, more preferably 99.5 / 0.5 to 97.4 / 2.6, particularly preferably 99.4 / 0.6 to 97.6 / 2.4, Most preferably, it is 99.3 / 0.7 to 97.8 / 2.2. When the cellulosic binder / anionic surfactant is larger than 99.8 / 0.2, the dissolution of the cellulosic binder in water becomes insufficient, and there is a problem of extrudability when producing a cement extrudate. And the problem of quality of the resulting cement extrudate cannot be solved. On the other hand, if the cellulose binder / anionic surfactant is smaller than 97.0 / 3.0, the action as an AE agent in the admixture for cement extrusion is increased, and a large amount of bubbles are held in the mortar. The dimensional stability of the molded product is deteriorated and the quality is lowered. In addition, the cellulose-based binder dissolves in water very quickly, and the components such as pulp powder and fibers that are normally used in cement extrusion molding mixtures do not fully disperse rapidly, resulting in a viscosity that is insufficiently dispersed. A high-viscosity mortar will be prepared with the inclusion of. As a result, the problem of the quality of the cement extrusion cannot be solved.

In addition to the cellulose-based binder and the anionic surfactant described above, other components described later may be blended in the admixture for cement extrusion.
As for the admixture for cement extrusion molding, for example, a cellulose binder and an anionic surfactant are used, and a cellulose binder / anionic surfactant is 99.8 / 0.2 to 97.0 / 3.0. It is obtained by mixing and performing the process 1 which manufactures the admixture for cement extrusion. In step 1, a Nauta mixer, a Henschel mixer, a ribbon mixer, or the like may be used.

[Cement extrusion mixture and its production]
The mixture for cement extrusion molding of the present invention is a mixture containing cement, a cellulosic binder and an anionic surfactant, and used for cement extrusion molding. In this cement extrusion molding mixture, a cement extrusion molding admixture is blended as a cellulosic binder and an anionic surfactant. In the cement extrusion molding mixture, the explanation of the cellulose-based binder, the anionic surfactant and the like is as described in the cement extrusion molding admixture.
Examples of the cement blended in the cement extrusion molding mixture include ordinary Portland cement, blast furnace cement, early-strength cement, fly ash cement, alumina cement, and the like. Good.

The inorganic material is a material which requires cement and may contain an inorganic aggregate, and may actually be a material containing an inorganic aggregate. Examples of the inorganic aggregate include silica sand, silica stone powder, blast furnace slag, silica fume, fly ash, kaolin fired product, limestone powder and the like, and one or more kinds may be used in combination.
In the inorganic material, the optimum blending according to the application should be carried out. The weight ratio of the cement and the inorganic aggregate contained in the inorganic material (cement / inorganic aggregate) is preferably 80/20 to 30/70, More preferably, it is 75 / 25-35 / 65, Most preferably, it is 70 / 30-40 / 60. If the cement / inorganic aggregate exceeds 80/20, the dimensional change before and after hydraulic hardening becomes too large, which is inappropriate. On the other hand, if the cement / inorganic aggregate is smaller than 30/70, a problem occurs in the strength of the obtained cement-extruded product after hydraulic hardening.

Further, the blending amount of the admixture for cement extrusion blended as the cellulose binder and the anionic surfactant is usually 0.3 to 3 parts by weight, preferably 100 parts by weight of the inorganic material essential for cement. Is 0.4 to 2.8 parts by weight, more preferably 0.5 to 2.5 parts by weight. When the blending amount of the admixture for cement extrusion is less than 0.3 parts by weight, when the mortar obtained from the mixture for cement extrusion is extruded to produce a cement extrusion, the extrusion pressure is high and the extrusion speed is high. Occurrence of unstable phenomenon, that is, extrudability is deteriorated, and the surface condition and discharge state of the resulting cement extrusion molding are irregular, and the problem that the dimensional accuracy is low, that is, the quality is lowered, etc. There are things to do. On the other hand, when the blending amount of the admixture for cement extrusion exceeds 3 parts by weight, the performance improvement corresponding to the blending amount is not seen. Rather, the mortar obtained from the mixture for cement extrusion molding is extruded to cement extrusion molding. When manufacturing a product, the mortar hardness is low, the extrusion speed becomes unstable, the extrudability is lowered, the design property of the edge part is lowered, and the quality due to undulation may be lowered. .
In the step 2, the cement extrusion mixture is produced by mixing the cement extrusion admixture with an inorganic material essentially containing cement. Step 2 of mixing the admixture for cement extrusion and the inorganic material is performed by blending 0.3 to 3.0 parts by weight of the admixture for cement extrusion with 100 parts by weight of the inorganic material essential for cement. . Further, the mixing of both is performed after 24 hours or more have elapsed since the admixture for cement extrusion was prepared, whereby the solubility of the cellulose-based binder in the admixture for extrusion in mortar is increased. As a result, it becomes possible to more fully solve both the problem of extrudability when producing a cement extrudate from mortar and the quality of the resulting cement extrudate. Moreover, the compounding quantity of the admixture for cement extrusion at the time of manufacturing a cement extrusion molding can be lowered | hung.

[Cement Extrusion and its Production]
The cement extrusion molding of the present invention is a molding formed by blending water into a cement extrusion molding mixture and extrusion molding the resulting mortar. The cement extrusion molding is obtained by, for example, dry dispersion of a cement extrusion molding mixture in a mixer, adding a predetermined amount of water while dry dispersing, and kneading with a kneader or the like as necessary. A molded product obtained by vacuum extrusion molding of mortar is preferred.
As the mixer used above, a mixer having a liquid addition mechanism is preferable. For example, a mixer having two functions of floating diffusion mixing by main blades and high-speed shear dispersion by chopper blades; A Gemixer, a diffusion kneader type mixer; an omni mixer, a reverse flow type high speed mixer, an Eirich mixer, or the like is preferable.

Mortar is obtained by blending water into the cement extrusion mixture.
The ratio of the mixture for cement extrusion and water is generally the weight ratio of water to the inorganic material that requires cement (usually, the inorganic material that includes cement and requires inorganic aggregate) (inorganic material / water). Is expressed as The inorganic material / water is preferably 85/15 to 65/35, more preferably 82/18 to 62/38, and particularly preferably 80/20 to 60/40. When the inorganic material / water is smaller than 65/35, the hardness of the mortar is extremely low, the extrusion molding becomes difficult, and the strength of the extrusion molding plate may be lowered. On the other hand, if the inorganic material / water is larger than 85/15, the mortar becomes incoherent and extrusion molding may be difficult.

The obtained mortar is kneaded using a kneader as necessary to obtain a more uniform mortar. As the kneading machine, an apparatus in which two stirring rotors are provided in parallel in a kneading tank and the contents are kneaded by rotating the respective stirring rotors in the opposite directions; a double-arm kneader or the like is preferable.
The cement extrusion is obtained by extruding mortar, but if the extrusion performed here is vacuum extrusion, bubbles in the extrusion are reduced, and the appearance and dimensional stability are improved. Further, it is preferable because spring back and the like when the extruded product is discharged from the mold can be prevented.

As a molding machine (vacuum extrusion molding machine) used for vacuum extrusion molding, for example, a screw extruder for a cement or a ceramic, a plunger extruder, and the like can be given. As a commercially available molding machine, for example, a vacuum extrusion molding machine for cement (manufactured by Ishikawa Tokiko Co., Ltd.), a kneading-vacuum extrusion molding machine (manufactured by Miyazaki Tekko Co., Ltd.), a vacuum extrusion molding machine (Honda Honda) Manufactured). In particular, the kneading-vacuum extrusion molding machine has a series of steps from preparation of a mixture for cement extrusion molding to extrusion molding, where the above-mentioned mixer and the portion having the functions of the kneading machine are connected to the extrusion molding machine. Equipment.
Cement extrusion molding is performed as follows, for example. 1) The mortar is pre-kneaded in a pug mill / pug screw part of a vacuum extrusion molding machine, and then the mortar is sent to a vacuum deaeration chamber to remove bubbles taken in the mortar. 2) The mortar is further dropped into the barrel, sent to a die attached to the end of the barrel by a screw or a plunger, and passed through the die to obtain cement extrusions having various cross-sectional shapes.

Cement extrusion molding can be performed with reference to “extrusion changes cement-based materials” (Moriko, Baba Akio; Cement Concrete, No. 598, p.9-20, issued in December 1996). it can.
Examples of important extrusion conditions in this vacuum extrusion include extrusion pressure and extrusion speed. If the extrusion pressure is too high, the load on the machine may increase and the life of the mold, screw, barrel, etc. may be shortened. It may also be a problem with increasing power consumption. Therefore, generally a low extrusion pressure is desired.

Moreover, since extrusion speed is directly related to productivity, it is generally better to be faster. When the extrusion speed is slow, poor extrusion of the barrel wall and mortar of the extruder often leads to a decrease in extrusion speed, process instability due to slow speed, increase in extrusion pressure, etc. The quality may also be degraded.
The resulting cement extruded product is dried and cured, and is subjected to curing, steam curing, cutting, finishing, etc. using an autoclave as necessary. Widely used for materials.

[Other ingredients]
In the cement extrusion molding admixture and cement extrusion molding mixture described above, other components described below can be blended within a range that does not have a significant adverse effect on the effects obtained by the present invention. It should be noted that the extrusion admixture is solid and preferably in powder form, and other components that prevent such a state from being formed should not be added to the extrusion admixture. It is desirable to blend in the mixture for use.

(Ingredients that can be incorporated into cement extrusion admixture or cement extrusion mixture)
As materials that are used to improve the strength of cement-extruded products and have no influence on safety and health, inorganic materials such as glass fibers; fibrous materials such as organic fibers such as pulp, vinylon fibers, and polypropylene fibers can be blended.
For lightweighting, inorganic lightweight aggregates such as perlite; organic foaming agents such as polystyrene-based organic foaming agents, fly ash, and organic hollow microspheres can be blended.
As a setting time adjusting agent, silicofluoride such as magnesium silicofluoride; boric acids such as boric acid; oxycarboxylic acids such as gluconic acid, glucoheptonic acid, citric acid and tartaric acid and salts thereof; lignin sulfonic acid, humic acid, tannic acid, etc. A high-molecular-weight organic acid and a set retarder such as a salt thereof can be blended.

As a setting time adjusting agent, chlorides such as calcium chloride, sodium chloride and potassium chloride; thiocyanates such as sodium thiocyanate; nitrites such as calcium nitrite, sodium nitrite and potassium nitrite; calcium nitrate and sodium nitrate Nitrates such as potassium nitrate; sulfates such as calcium sulfate, sodium sulfate and potassium sulfate; carbonates such as calcium carbonate, sodium carbonate and potassium carbonate; coagulation accelerators and rapid setting by inorganic compounds such as sodium silicate (water glass) An agent etc. can be mix | blended.
As setting time adjusting agents, amines such as diethanolamine (DEA) and triethanolamine (TEA); coagulation accelerators and rapid setting agents by organic compounds such as calcium salts of organic acids such as calcium formate and calcium acetate Can be blended.

In order to prevent excessive shrinkage of the extruded plate and the extruded product before and after hydraulic hardening, a shrinkage reducing agent such as polyalkylene glycols such as polypropylene glycol and polypropylene polyethylene glycol, and alkoxy polypropylene glycol acrylates can be blended.
Polyvinyl alcohol; Cellulose water-soluble polymers such as carboxymethylcellulose; Starch polymers such as hydroxypropylated starch; Polyacrylamide, Polyacrylic acid Acrylic water-soluble polymers such as soda; biopolymers such as xanthan gum and guar gum; anionic acrylic resin, EVA (ethylene vinyl acetate emulsion), PAE (polyacrylate emulsion), PVAC (polyvinyl acetate emulsion), VAVeoVa ( Emulsion thickeners such as vinyl acetate vinyl versatate emulsion) and separation reducing agents can be blended.
Next, components that are preferably blended into the cement extrusion mixture will be described.

(Ingredients that can be incorporated into cement extrusion molding mixture)
As an antifoaming agent, a polyoxyalkylene antifoaming agent mainly composed of ethylene oxide or propylene oxide, a polypropylene glycol antifoaming agent, a mineral oil antifoaming agent, a modified silicone antifoaming agent, dimethylpolysiloxane, or the like can be blended. .
As a swelling agent, aluminum powder or the like can be blended. Moreover, a rust preventive, a coloring agent, etc. can be mix | blended.

  As waterproofing and water repellents, calcium chloride, sodium silicate, siliceous powder, zirconium compounds, fatty acid soaps, fatty acids, fatty acid esters, fatty acid compounds obtained by emulsifying these, silicone oil, silicone emulsion, paraffin, paraffin emulsion Asphalt emulsion, oil-containing waste clay, rubber latex, etc. can be blended.

In order to contribute to fluidization of cement and inorganic materials and improve fluidity and workability, the following ingredients are blended as AE agent, water reducing agent, AE water reducing agent, fluidizing agent, high performance AE water reducing agent, etc. can do.
As an AE agent, an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, etc. can be mix | blended.

As water reducing agent / AE water reducing agent, lignin sulfonate or its derivatives, oxycarboxylate, polyol derivative, polyoxyethylene alkylallyl ether derivative, alkylallylsulfonate formalin condensate, melamine sulfonate formalin condensate Polycarboxylic acid polymer compounds can be blended.
As a fluidizing agent, naphthalene sulfonate formalin condensate, melamine sulfonate formalin condensate, polycarboxylic acid compound, polystyrene sulfonate, and the like can be blended.

As a high-performance AE water reducing agent, a mixture of naphthalene sulfonate formalin condensate and lignin sulfonic acid, a mixture of naphthalene sulfonate formalin condensate and polycarboxylic acid polymer compound, melamine sulfonate formalin condensate and slump loss A mixture of a reducing agent, a polycarboxylic acid compound, a polycarboxylic acid ether compound, an aromatic aminosulfonic acid compound, and the like can be blended as necessary within a range that does not adversely affect the effects of the present invention.
It goes without saying that the cement extrusion molding mixture is mainly composed of an inorganic material essential for cement, and it is preferable to avoid blending components other than the inorganic material essential for cement. Therefore, 90/10 to 99.7 / 0.3 is preferable as the weight ratio of the inorganic material essential for cement and the other components (inorganic material essential for cement / other components).
Note that the admixture for cement extrusion, the mixture for cement extrusion, and the cement extrusion product of the present invention do not contain any asbestos.

  Examples of the present invention will be specifically described below together with comparative examples. The present invention is not limited to these examples.

[Example 1]
99.5 parts by weight of a cellulose binder a (hydroxyethylmethylcellulose, Marporose ME-350T, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) shown in Table 2 was put into a Nauta mixer type mixer (SV mixer 50 type, manufactured by Shinko Pantech). While fully stirring under the stirring conditions of 12 rpm for rotation and 60 rpm for revolution, 0.5 part by weight of surfactant A shown in Table 1 was added and stirring was continued for 30 minutes. In addition, the viscosity (20 degreeC) of the 1 weight% aqueous solution of the cellulose binder a used here was 10700 mPa * s (B type viscometer, NO4, 30 rpm).
After completion of the stirring, the mixture obtained with an atomizer (AT-50, manufactured by Dalton) was pulverized, and then passed through a vibrating mesh of 20 mesh (opening: 870 μm) to obtain Admixture 1.

[Examples 2 to 7]
In Example 1, Admixtures 2 to 7 were obtained in the same manner as in Example 1 except that the types and amounts of the surfactant A and the cellulose-based binder a were changed to those shown in Table 3, respectively.

[Comparative Examples 1-8]
In Example 1, Admixtures 8 to 15 were obtained in the same manner as in Example 1 except that the types and amounts of the surfactant A and the cellulose-based binder a were changed to those shown in Table 3, respectively.
In addition, in the admixture 14 of the comparative example 7, surfactant is not mix | blended and it consists only of the cellulose-type binder a.
The surfactants and cellulose binders used in Examples 1 to 7 and Comparative Examples 1 to 8 (Admixtures 1 to 15) are shown in detail in Tables 1 and 2, respectively.

A mixture for cement extrusion molding was prepared using the admixture obtained above, water was added to produce a mortar, and extrusion molding was performed to obtain a cement extrusion molding.
Examples, comparative examples, reference examples and standard examples will be described below. In addition, a reference example shows the model which melt | dissolved all the mix | blended cellulose binders. The standard example shows an example of standard extrusion using a cellulose-based binder that is widely used as an admixture for cement extrusion.

[Example A1]
(Cement extrusion mixture)
The components shown in Table 4 below (total 102 parts by weight) and 1 part by weight of Admixture 1 were placed in a Laedige mixer (M20 type, manufactured by Matsubo) and stirred for 5 minutes under stirring conditions of 100 rpm rotation and 2400 rpm chopper. The mixture was mixed well to obtain a cement extrusion mixture.

(mortar)
While stirring the obtained cement extrusion mixture in a Laedige mixer, 25 parts by weight of water is sprayed on the cement extrusion mixture in about 2 to 2.5 minutes, and rotation is started from the start of water spraying. The mixture was stirred for 5 minutes under stirring conditions of 100 rpm and chopper 2400 rpm to dissolve hydroxyethyl methylcellulose, and a homogeneous mixture was obtained.
The obtained homogeneous mixture was placed in a 10 L double-arm kneader (HBN-10D, manufactured by Honda Seiko Co., Ltd.) and sufficiently kneaded for 3 minutes, and then a mortar that was a clay-like highly viscous substance was prepared. .

(Extrusion molding)
The obtained mortar was extrusion molded using a vacuum extrusion molding machine (DE-50D, manufactured by Honda Seiko Co., Ltd.) to produce a cement molded plate (cement extruded product).
The molding conditions are as follows: the internal temperature of the vacuum extruder is 30 ° C., the degree of vacuum is −0.096 MPa or less, a mold (40 mm × 10 mm) is used, and the room temperature is 25 ° C. and the humidity is 60%. A flat cement extrusion was obtained.
Evaluation of the quality (surface state, discharge state, dimensional accuracy) of the obtained cement extruded product, extrudability (extrusion pressure, extrusion speed, standard deviation of speed) at the time of extrusion molding, and hardness of the cement extruded product Evaluation was performed according to the criteria, and the results are shown in Table 5. The evaluation was performed at room temperature of 25 ° C. and humidity of 60%.

[Examples A2 to A14]
In Example A1, except that the type and amount of the admixture were changed to those shown in Table 5, mixing was performed in the same manner as in Example A1 to obtain cement extrusion molding mixtures, respectively.
From the obtained mixture for cement extrusion molding, mortars were respectively prepared in the same manner as in Example A1, extruded to produce cement extrusion moldings, evaluated in the same manner as in Example A1, and the results shown in Table 1. This is shown in FIG.

[Reference Example A1]
As a complete dissolution model of a cellulose binder, a cellulose binder (Marporose ME-350T) was dissolved in water to prepare a high viscosity aqueous solution having a concentration of 3% by weight, which was designated as liquid admixture-1.
(Method for preparing liquid admixture-1)
While stirring hot water of 90 ° C. or higher to the cellulose-based binder a, it was gradually added so as not to cause mamaco to form a powdered hot water dispersion. Subsequently, this hot water dispersion is cooled while stirring to dissolve the cellulose binder a. After cooling, water was added so that the concentration of the cellulose-based binder a was 3% by weight to obtain Liquid Admixture-1. Liquid admixture-1 was a high-viscosity aqueous solution, and had a viscosity of 1050000 mPa · s (20 ° C., B-type viscometer, NO6, 1 rpm) and was an ultra-high viscosity sealant. The preparation and use of such an ultra-high viscosity product is unsuitable from the viewpoint of industrial production in current cement extrusion.

Each component shown in Table 4 (cement, inorganic aggregate, polypropylene fiber and pulp powder; 102 parts by weight in total) was put in a Laedige mixer (M20 type, manufactured by Matsubo) and stirred at 100 rpm for rotation and 2400 rpm for chopper. For 5 minutes and mixed well to obtain a premix.
Then, 25.8 parts by weight of liquid admixture-1 was added using an airless spray device (Graco President 205T and its system) while stirring the pre-mix in a Roedige mixer. The mixture was sprayed to the premix in 5 minutes, and stirred for 5 minutes under the stirring conditions of rotation of 100 rpm and chopper of 2400 rpm from the start of spraying to obtain a homogeneous mixture for cement extrudate. Liquid admixture-1 (25.8 parts by weight) contains 0.8 parts by weight of cellulose binder a and 25 parts by weight of water.

The obtained mixture was put in a 10 L double arm kneader (HBN-10D, manufactured by Honda Tekko Co., Ltd.) and sufficiently kneaded for 3 minutes, and then a mortar which was a clay-like high viscosity substance was prepared.
In Reference Example A1, except that this mortar was used, a cement extruded product was produced by extrusion molding in the same manner as in Example A1, evaluated in the same manner as in Example A1, and the results are shown in Table 6. In this cement extruded product, the extrudability is acceptable, but the quality is determined to be unacceptable.

[Standard Examples A1 to A5]
In Example A1, except that the type and amount of the admixture were changed to those shown in Table 7, mixing was performed in the same manner as in Example A1 to obtain cement extrusion molding mixtures, respectively.
From the obtained mixture for cement extrusion molding, mortars were respectively prepared in the same manner as in Example A1, extruded to produce cement extrusion moldings, evaluated in the same manner as in Example A1, and the results shown in Table 1. 7 shows.

Standard examples A1 to A5 show examples of standard extrusion using a cellulose-based binder that is widely used as an admixture for cement extrusion.
The standard example A4 is an example in which 1.2 parts by weight of the cellulosic binder a is added to 100 parts by weight of the cement and the inorganic aggregate. In the standard example A4, both the quality and the extrudability were satisfactory, and this was a standard blend with a cellulosic binder, and was handled as a standard for the quality and extrudability of the cement extrusion.
In Examples A1 to A14, the admixture for cement extrusion was added in an amount of less than 1.2 parts by weight based on 100 parts by weight of the cement and the inorganic aggregate, but the cement was satisfactory in both quality and extrudability. An extrudate is obtained.

[Comparative Examples A1 to A8]
In Example A1, except that the type and amount of the admixture were changed to those shown in Table 8, mixing was performed in the same manner as in Example A1 to obtain cement extrusion molding mixtures, respectively.
From the obtained mixture for cement extrusion molding, mortars were respectively prepared in the same manner as in Example A1, extruded to produce cement extrusion moldings, evaluated in the same manner as in Example A1, and the results shown in Table 1. This is shown in FIG.

[Comparative Examples A9 to A15]
When preparing the mixture for cement extrusion molding, the components shown in Table 4 below (total of 102 parts by weight) and the predetermined amount of admixture 14 shown in Table 8 were placed in a Laedige mixer (M20 type, manufactured by Matsubo). Then, a predetermined amount of surfactant A or surfactant C shown in Table 8 was added. Immediately thereafter, the mixture was stirred for 5 minutes under stirring conditions of rotation of 100 rpm and chopper of 2400 rpm, and mixed well to obtain cement extrusion molding mixtures.
From the obtained mixture for cement extrusion molding, mortars were respectively prepared in the same manner as in Example A1, extruded to produce cement extrusion moldings, evaluated in the same manner as in Example A1, and the results shown in Table 1. This is shown in FIG.

[Quality of cement extrusions]
(Surface condition)
The cement extrusion molded product extruded from the mold at the time of cement extrusion molding was visually observed, and the surface condition was evaluated according to the following evaluation criteria.
○: The surface of the cement extruded product is smooth and good.
Δ: Some unevenness is observed on the surface of the cement extrusion.
X: Concavities and convexities are observed on the surface of the cement extrusion, or cracks are observed in the cement extrusion.

(Discharge state)
The cement extrusion molded product extruded from the mold at the time of cement extrusion molding was visually observed, and the discharge state was evaluated according to the following evaluation criteria.
○: Cement extrudate is extruded straight and stably.
(Triangle | delta): A slight change is seen when a cement extrusion molding is extruded.
X: Changes such as meandering, waving, blistering, etc. are observed when a cement extruded product is extruded, and it is not extruded straight and stably.

(Dimensional accuracy)
The dimension of the cement extrusion molded product extruded from the mold at the time of cement extrusion molding was measured and compared with the mold dimension to evaluate the dimensional accuracy according to the following evaluation criteria.
○: Both the width and thickness error of the cement extrusion product are 0.2 mm or less. Δ: Both the width and thickness error of the cement extrusion product are 0.2 mm or more and 0.3 mm or less. Both errors are 0.3mm or more

[Extrudability during extrusion]
(Extrusion pressure)
At the time of cement extrusion, the average pressure reading indicated by the pressure gauge attached to the vacuum extruder is x, and the average pressure reading in the standard example A4 using the admixture 14 is y (x / y) x100 was calculated as the extrusion pressure. Then, the extrusion pressure was evaluated according to the following evaluation criteria. Here, the lower the extrusion pressure, the lower the load on the extruder and the better the extrudability.
×: 115 or more Δ: 105 or more and less than 115 ○: 95 or more and less than 105 ◎: less than 95

(Extrusion speed)
At the time of cement extrusion, the value measured for the flow rate of the cement extrudate when extruded from the vacuum extruder is a, and the speed reading in the standard example A4 using the admixture 14 is b. (A / b) × 100 was calculated as the extrusion speed. Then, the extrusion speed was evaluated according to the following evaluation criteria. Here, the higher the extrusion speed, the higher the productivity and the better the extrudability.
◎: 105 or more ○: 95 or more and less than 105 Δ: 85 or more and less than 95 ×: less than 85

(Standard deviation of speed)
When the cement extrusion molding is performed, the standard deviation of the flow rate of the cement extruded product when extruded from the vacuum extruder is A, and the standard deviation of the velocity in the standard example A4 using the admixture 14 is B ( A / B) × 100 was calculated as the standard deviation of speed. Then, the standard deviation of speed was evaluated according to the following evaluation criteria. Here, the smaller the standard deviation of the speed, the more uniform the finished state of the mortar and the better the extrudability.
×: 150 or more Δ: 125 or more and less than 150 ○: 75 or more and less than 125 ◎: less than 75

[Comprehensive judgment of quality and extrudability]
Among the three evaluation items of quality, the case where there were two or more ◯ and there was no x was determined as pass (go), and the others were determined as fail (fail).
Among the three evaluation items of extrudability, a case where ま た は and / or ○ was 2 or more and there was no x was judged as pass (go), and the others were judged as fail (fail).

[Hardness of cement extrusions]
The hardness of the cement extrusion molded product extruded from the mold during cement extrusion molding was measured with a clay hardness meter (manufactured by Nippon Isogo), and the hardness was evaluated according to the following evaluation criteria. Here, “hard” generally indicates that the extrusion pressure is high. “Soft” indicates that the extrusion pressure is low, but it is necessary that the extrusion pressure is low. However, if the mortar hardness is “soft”, the edge shape will deteriorate in design and the dimensional accuracy will decrease. Problems may occur. In the case of “suitable”, there are few problems in terms of quality and extrudability.
Hard: 12.5 or more Suitable: 11.5 or more, Less than 12.5 Soft: Less than 11.5

From the results shown in Tables 5 to 7, the following considerations can be made.
(Comparison of Example A6, Reference Example A1 and Standard Examples A1 to A5)
In Example A6, the quality and extrudability almost equal to or higher than those of Reference Example A1 were obtained, and it can be seen that the blended admixture was dissolved to the same extent as Reference Example A1.
On the other hand, the standard examples A1 and A2 show clearly inferior quality and extrudability, indicating that the cellulosic binder is insufficiently dissolved compared to the reference example A1. As in standard examples A3, A4 and A5, when a large amount of cellulose binder is blended, the quality and extrudability equal to or higher than those of Reference Example A1 are exhibited.

(Comparison of Examples A1 to A14 and Comparative Examples A1 to A8)
In Examples A1 to A14, good quality and extrudability are shown as compared with Comparative Examples A1 to A8, although the amount of the admixture in the mixture for extrusion molding is small.
On the other hand, Comparative Examples A2 to A8 using those that do not satisfy the anionic surfactant defined in claim 1 or 5 do not satisfy both the quality and the extrudability, but to the mixture for extrusion molding. It is not possible to reduce the amount of admixture added.
In Comparative Example A1 in which a large amount of the anionic surfactant specified in claim 1 or 5 is blended, the extrudability is good but the quality is inferior, and both the quality and extrudability are not satisfied. The amount of the admixture added to the molding mixture cannot be reduced.

(Comparison of Examples A1 to A14 and Comparative Examples A9 to A15)
In Examples A1 to A14, a mixture for cement extrusion molding was prepared after 24 hours or more had passed since the admixture was prepared, and the quality and extrudability were improved as compared with Comparative Examples A9 to A15. .
On the other hand, as in Comparative Examples A9 to A15, when an anionic surfactant is blended directly with an inorganic material rather than as an admixture blended with an anionic surfactant and a cellulose binder, Anionic surfactants mainly act on cement and inorganic materials to slightly improve the fluidity of mortar, but do not satisfy both quality and extrudability as in Examples A1 to A14.
Preparing a mixture for cement extrusion after the admixture has been prepared for 24 hours or more (pre-formulation of a cellulose binder and an anionic surfactant) contributes to improving the solubility of the cellulose binder, Effective for improving the quality and extrudability of extruded products.

Claims (8)

An admixture used for cement extrusion comprising a cellulosic binder and an anionic surfactant,
The cellulose binder contains at least one selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkylalkyl cellulose, and the viscosity of a 1% by weight aqueous solution of the cellulose binder is 6000 to 30000 mPa · s (B-type viscosity). The measurement temperature is 20 ° C.)
The anionic surfactant contains at least one selected from the group consisting of sodium alkyl sulfate, sodium α-olefin sulfonate and sodium alkyl benzene sulfonate,
The weight ratio of the cellulose binder and the anionic surfactant (cellulose binder / anionic surfactant) is 99.8 / 0.2 to 97.0 / 3.0,
Admixture for cement extrusion.   The admixture for cement extrusion according to claim 1, wherein the anionic surfactant is solid at 20 ° C. A cement extrusion mixture used for cement extrusion, comprising cement, a cellulosic binder and an anionic surfactant,
3 to 3 parts by weight of the admixture for cement extrusion molding according to claim 1 or 2 as the cellulose binder and an anionic surfactant is blended with 100 parts by weight of the inorganic material essential for the cement. Become
Cement extrusion mixture.   The mixture for cement extrusion according to claim 3, wherein the blending is carried out after 24 hours or more have passed since the admixture for cement extrusion was prepared. Cellulose binder containing at least one selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose and having a 1% aqueous solution viscosity of 6000-30000 mPa · s (B-type viscometer, measuring temperature 20 ° C.) When,
An anionic surfactant comprising at least one selected from the group consisting of sodium alkyl sulfate, sodium α-olefin sulfonate and sodium alkyl benzene sulfonate;
Cement extrusion by mixing so that the weight ratio of the cellulose-based binder and the anionic surfactant (cellulose-based binder / anionic surfactant) is 99.8 / 0.2 to 97.0 / 3.0 Step 1 for producing a molding admixture;
Including the step 2 of blending 0.3 to 3.0 parts by weight of the admixture for cement extrusion with 100 parts by weight of an inorganic material essential for cement, and producing a mixture for cement extrusion,
A method for producing a cement extrusion mixture.   The method for producing a cement extrusion molding mixture according to claim 5, wherein the anionic surfactant is solid at 20 ° C.   The manufacturing method of the mixture for cement extrusion molding of Claim 5 or 6 which performs the said process 2 24 hours or more after the said process 1. FIG.   Water is added to the cement extrusion molding mixture according to claim 3 or 4 and / or the cement extrusion molding mixture obtained by the production method according to any one of claims 5 to 7, and the resulting mortar is used. Extruded cement made by extrusion.