JPH1179802A - Powdery self-leveling cement composition and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition easy in a kneading work at a building site, little in the deterioration of flowability with the passage of time and excellent in initial flowability and working characteristics by mixing a cement with silica to whose surface a polyether-based fluidizing agent is adhered. SOLUTION: Silica having particle diameters in a particle diameter range of 10-2,000 μm and having an average particle diameter of 50-500 μm is immersed in the aqueous solution of a polyether-based fluidizing agent, dehydrated and subsequently dried to obtain the silica to whose surface the polyether-based fluidizing agent is adhered in an amount of 0.1-100 pts.wt. per 100 pts.wt. of the silica. The silica is compounded with a cement so that a value of (cement)/[(cement)f(silica to whose surface the polyether-based fluidizing agent is adhered)] is 55-65 wt.%. The silica to whose surface the polyether-based fluidizing agent is adhered may be mixed with silica to whose surface the polyether-based fluidizing agent is not adhered, so that the amount of the polyether-based fluidizing agent is 0.1-5 pts.wt., preferably 0.5-3 pts.wt., per 100 pts.wt. of the total amount of the silica.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-leveling cement composition used as a flooring material for general buildings. Specifically, the present invention relates to a self-leveling cement composition that not only facilitates kneading at a construction site because each component is present in a powder form, but also provides a self-leveling material having excellent flow characteristics after kneading.

[0002]

2. Description of the Related Art Self-leveling materials are classified into an on-site kneading type and a factory kneading type according to a slurry supply method. [For example, Sato, "The Current State and Prospects of SL Materials", Architectural Finishing Technology, May issue. , P. 79, (1992)], each of which has advantages and disadvantages. For example, the factory kneading type does not require kneading at the construction site, and can strictly control the blending of each component. However, since the pot life of the slurry is finite, the factory (preparation) to the site (construction) The major disadvantage is that attention must be constantly paid to the material transfer time between the two. On the other hand, in the case of the on-site kneading type, such worries are completely unnecessary. Instead, it is necessary to add and knead various components at the construction site. It has the disadvantage of causing a significant reduction. In addition, it is desirable that additives that exert a large effect when added in small amounts, such as fluidizers, be added and prepared in advance at a factory where strict component management is possible. The presence of liquid components in the composition has been an obstacle. From the above, there has been a strong demand for providing a cement composition in which all components including a fluidizing agent are supplied in powder form in order to enable on-site kneading.

Naturally, various inorganic components such as cement can be supplied in a powder state. Regarding various organic additives, water reducing agents, defoamers, thickeners, etc. are powdered solids. Can be supplied. However, regarding the fluidizing agent, which is an essential component in ensuring self-leveling properties in the self-leveling cement composition, so-called various polyether-based fluidizing agents having a long-chain alkyl ether group in a side chain thereof. However, since these polyether-based fluidizing agents are sticky liquid substances at normal temperature, it is very difficult to powder these substances themselves. It cannot be used for on-site kneading type self-leveling materials. As means for solving this problem, Japanese Patent Application Laid-Open No. 6-239652 discloses a method in which a polycarboxylic acid-based copolymer, which is a liquid fluidizing agent, is adhered to inorganic powder to form a powder. In this method, powdering is certainly possible, but since the inorganic powder used is an ultrafine powder such as ultrafine silica,
However, there remains a problem that it is extremely difficult to apply a sticky liquid fluidizing agent to form a powder.

[0004]

SUMMARY OF THE INVENTION The present invention provides a self-leveling cement composition in which the above-mentioned problems of the prior art have been solved, that is, a powdery composition containing a fluidizing agent as a component. It is easy to knead at a construction site, and to provide a powdery self-leveling cement composition that provides a self-leveling material having good flow characteristics after kneading, and of the powdery self-leveling cement composition An object of the present invention is to provide a manufacturing method that enables easy manufacturing.

[0005]

SUMMARY OF THE INVENTION The present inventors have reported that silica sand is the most suitable substance for immobilizing a sticky polyether-based fluidizing agent, and that silica sand having a polyether-based fluidizing agent attached thereto. The present inventors have found that a cement composition composed of cement and cement is a means for solving the above-mentioned problems, and completed the present invention. That is, the present invention relates to a powdery self-leveling cement composition comprising cement and silica sand having a polyether-based fluidizing agent adhered to its surface. Further, the present invention provides a method of treating silica sand with an aqueous solution of a polyether-based fluidizing agent, followed by dehydration and drying to obtain silica sand to which the polyether-based fluidizing agent has adhered. The present invention relates to a method for producing a powdery self-leveling cement composition in which sand and cement are mixed.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The cement is also a main component in the powdery self-leveling cement composition of the present invention. However, as the cement used in the present invention, portland cements such as ordinary, early-strength, ultra-high-strength, etc. , Silica, fly ash and the like, various kinds of mixed cements, alumina cements, quick-setting cements, and the like can be used. It is also possible to use mixtures of these.

[0007] Quartz sand is a sand mainly composed of quartz grains containing 90% by weight or more of SiO ₂ , and various kinds of sand such as natural silica sand, frog-eyed silica sand and artificial silica sand are known. Can be used. The particle size range is 10 to 2000 μm.
However, the particle size range suitably used in the present invention is in the range of 50 to 500 μm in average particle size. If the average particle size is less than 50 μm, depending on the type of the polyether-based fluidizing agent to be attached, it may be difficult to adhere to silica sand to form a powder, and the average particle size may be 500 μm.
If it is larger, the surface appearance of the self-leveling material after the treatment may be impaired, or the smoothness or strength may be reduced.

The polyether-based fluidizing agent used in the present invention comprises (A) a general formula of CR ₁ H = CR ₂ (CH ₂ ) _x COO
(AO) _n R ₃ [where R ₁ and R ₂ are H or CH ₃
R ₃ is H or an alkyl group having 1 to 3 carbon atoms, A is (CH ₂ ) ₂ or (CH ₂ ) ₃ , x is 0,
A vinyl monomer having a long-chain alkyl ether group in the side chain, and (B) a general formula CR ₄ R ₅ ＣC
R ₆ COOM ₁ [where R ₄ , R ₅ and R ₆ are H, CH
₃ , (CH ₂ ) _y COOM ₂ (where y is 0, 1, 2,
M ₂ represents H, an alkali metal, an alkaline earth metal, ammonium, an alkyl ammonium or a substituted alkyl ammonium), M ₁ represents H, an alkali metal, an alkaline earth metal, ammonium, an alkyl ammonium Or a substituted alkylammonium] or a derivative thereof, and / or (C) a general formula CH ₂ ＣＲCR ₇ CH ₂ S
Allylsulfonic acid represented by O ₃ Y (where R ₇ represents H or CH ₃ , Y represents any of H, an alkali metal, an alkaline earth metal, ammonium, alkylammonium and substituted alkylammonium) or It is a copolymer with a derivative and has a long chain alkyl ether group in the side chain.

In the present invention, the above-mentioned (A)
A copolymer of a vinyl monomer having a long-chain alkyl ether group in the side chain and a vinyl monomer belonging to the above (B) and / or (C) is adhered to silica sand as a fluidizing agent. , (B) and (C) specific compounds belonging to each group include (A) methoxy polyethylene glycol, ethoxy polyethylene glycol, propoxy polyethylene glycol, methoxy polypropylene glycol, ethoxy polypropylene glycol or propoxy polypropylene glycol and acrylic acid, methacrylic acid. , Esterification of fatty acid with dehydrogenated product, and addition of polyethylene oxide or polypropylene oxide to acrylic acid, methacrylic acid, fatty acid dehydrogenated product,
(B) acrylic acid, methacrylic acid, crotonic acid, maleic anhydride, maleic acid, citraconic anhydride, citraconic acid, fumaric acid or an alkali metal salt thereof, an alkaline earth metal salt, an ammonium salt, an amine salt, a substituted amine salt,
(C) Allyl or substituted allyl sulfonic acid or a derivative thereof, for example, allyl sulfonic acid, methallyl sulfonic acid, or an alkali metal salt, an alkaline earth metal salt, an ammonium salt, an amine salt, or a substituted amine salt thereof.

The polyether copolymer formed from the vinyl monomer belonging to the above (A) and the vinyl monomer also belonging to the above (B) and / or (C) is not solid at room temperature but is soluble in water. It is a highly viscous liquid substance. The feature of the present invention resides in that the above-mentioned polyether-based copolymer is adhered to silica sand as a fluidizing agent and immobilized, and these polyether-based copolymers are used as one kind or a mixture of two or more kinds. However, various cement fluidizer aqueous solutions containing one or more of these polyether copolymers are commercially available, and the most convenient method is to use them.

[0011] The fixation of the polyether-based fluidizing agent by adhering it to silica sand is very simple in that an aqueous solution of the polyether-based fluidizing agent is brought into contact with silica sand and then dried to remove water. Can be achieved by the method As a specific method, any of conventionally known methods such as a spray drying method, a fluid drying method, and a coating method can be applied without any problem. The concentration of the aqueous solution to be used depends on the type of the polyether-based fluidizing agent to be used, but is preferably about 10 to 50% by weight from the viewpoint of uniformity of adhesion and operability of the immobilization treatment. In the silica sand to which the polyether-based fluidizing agent thus obtained adheres, the amount of the attached polyether-based fluidizing agent is
It is preferable that the amount be in the range of 0.1 to 100 parts by weight based on 100 parts by weight of silica sand. If this value is less than 0.1 parts by weight, the effect of improving the fluidity after slurrying by adding water is not sufficiently exhibited, and if this value is more than 100 parts by weight, the polyether-based fluidizing agent In some cases, problems such as formation of silica sand lumps, making it difficult to obtain a uniform slurry, and adhesion of silica sand, making handling difficult, may occur.

The powdery self-leveling cement composition of the present invention is composed of cement and silica sand having the above-mentioned polyether-based fluidizing agent adhered to its surface. / [(Cement) + (silica sand with polyether fluidizer attached to its surface)]
Is preferably in the range of 55 to 65% by weight.
Alternatively, silica sand having no polyether-based fluidizing agent attached to its surface may be added to silica sand having the above-mentioned polyether-based fluidizing agent attached to its surface. The amount of silica sand that the polyether fluidizer does not adhere to its surface is
The amount of the polyether-based fluidizer adhered to the silica sand having the polyether-based fluidizer adhered to its surface and (cement) / [(cement) + (the polyether-based fluidizer was adhered to the surface) Silica sand)], depending on the ratio, when the total amount of the existing silica sand is 100 parts by weight, the amount of the polyether-based fluidizing agent is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight. It is better to be.

[0013] The powdery self-leveling cement composition of the present invention comprises the above cement and a polyether-based fluidizing agent added to the essential components of silica sand adhered to the surface thereof within a range that does not impair the effect. There is no problem even if a hydraulic substance such as gypsum or quick lime, or a fine inorganic substance such as calcium carbonate or silica is added. Furthermore, in the present invention, in addition to these components, known organic additives existing as a solid at normal temperature, such as AE agents, AE water reducing agents, high-performance water reducing agents, and silicone-based, ester-based, ether-based, etc. A commonly used amount of a thickener such as a foaming agent, a nonionic cellulose derivative, polyacrylamide, or polyethylene oxide can be added. Particularly, in a self-leveling cement composition in which an appropriate balance between fluidity and pot life is required when used as a self-leveling material, saccharides, oxycarboxylic acids or alkali metal salts thereof, and alkali metal salts of ligninsulfonic acid are used. It is not possible to add 0.05 to 5 parts by weight of an organic or inorganic setting rate modifier which is solid at room temperature, such as aluminum sulfate and alkali metal carbonate, to 100 parts by weight of the hydraulic component in the cement composition. Produces favorable results.

The powdery self-leveling cement composition of the present invention is an essential component that exists in a single state, except that only a polyether-based fluidizing agent which is previously adhered to silica sand is used. Quartz sand with cement and polyether-based fluidizer attached thereto, and the specified amount of other additives used as appropriate may be mixed at the time of use, but a plurality or all of these components are already used. It may be composed of a mixed state (premix). In the latter case, the mixing of a plurality or all of the components can be easily performed by using a dry mixing device such as an ordinary powder mixer.

The powdery self-leveling cement composition of the present invention can be easily prepared by adding 20 to 30 parts by weight of water to 100 parts by weight of the composition and kneading the mixture by a known wet mixing method. It can be a self-leveling material and can be installed immediately. When the form of the composition is other than a single premix in which all the components are already contained, it is necessary to add and mix a specified amount of the components not contained in the premix composition. ,
Since both are powders, this can be easily performed, and there is no restriction on the order of addition of each component.

Hereinafter, the present invention will be described in more detail with reference to specific examples.

【Example】

Example 1 A polyether-based fluidizing agent aqueous solution [manufactured by Kao Corporation, trade name: Mighty 3000H ((A), (B) and (C) described above)
20% by weight aqueous solution of a copolymer of monomers belonging to each group]
After mixing 40 g and 300 g of silica sand (average particle size: 150 μm), the mixture was vacuum-dried at 40 ° C. for 3 hours and 100 g of silica sand was mixed.
2.7 g of silica sand to which 2.7 g of a polyether-based fluidizing agent adhered was obtained. To 300 parts by weight of silica sand to which the polyether-based fluidizing agent adhered, 360 parts by weight of Portland cement, 70 parts by weight of fly ash, and 245 parts of calcium carbonate
Parts by weight, 25 parts by weight of anhydrous gypsum, 4 parts by weight of retarder (powder), 0.6 parts by weight of defoamer (powder), and thickener (powder)
0.6 parts by weight was added and mixed using a powder mixer to obtain a powdery self-leveling cement composition. Next, the powdery self-leveling cement composition 100
Parts by weight and 24 parts by weight of water were kneaded for 3 minutes using a stirrer to prepare a self-leveling material. The properties of the prepared self-leveling material were measured and evaluated by the following methods. All measurements were made at a temperature of 20 ± 2 ° C and a humidity of 65
Performed at ± 5% RH. (1) Flow value Inside diameter 50 mm, height 5 placed on a vinyl chloride flat plate
The prepared self-leveling material was filled into a 1 mm vinyl chloride pipe (internal volume: 100 ml) immediately after the preparation, and then the pipe was gently pulled up and removed. The major axis and minor axis of the self-leveling material spread on the flat plate were measured, and the average value thereof was defined as the flow value. (2) Self-leveling property (flow loss) One end of an aluminum gutter having a rectangular cross section with a base of 25 mm and a height of 27 mm placed on a flat plate (internal volume: 100 m)
A weir was provided in l), and the self-leveling material prepared therein was filled immediately after the preparation. Immediately after filling (assuming 0 minutes elapsed), after 10 minutes, 20 minutes, and 30 minutes, the flow distance (distance from the weir) when the weir is removed is measured, and the time-dependent change in fluidity is measured. did. Table 1 shows the results.

[0017]

[Table 1]

Examples 2 to 4 The amount of the aqueous polyether fluidizer solution used was 25 g.
(Example 2), 47.5 g (Example 3) and 55 g (Example 4), and the amounts of adhering polyether fluidizer per 100 g of silica sand were 1.7 g, 3.2 g and 3.7 g, respectively. Silica sand to which a polyether-based fluidizing agent was adhered was obtained in the same manner as in Example 1 except that the self-leveling material was prepared from the obtained silica sand in exactly the same manner as in Example 1. Was measured. Table 1 shows the results.

Comparative Example 1 Self-leveling was carried out in exactly the same manner as in Example 1 except that the operation of adhering the polyether-based fluidizing agent to silica sand was omitted and silica sand having a polyether-based fluidizing agent adhesion amount of 0 was used. Materials were prepared and their properties were measured. Table 1 shows the results.

Comparative Example 2 Here, an example is shown in which silica sand to which the polyether-based fluidizing agent is not attached is used, and the polyether-based fluidizing agent is added and mixed at the time of preparing the self-leveling material. First, a powder mixture was obtained in exactly the same manner as in Example 1 except that silica sand having a polyether-based fluidizing agent adhesion amount of 0 was used. Next, 4 parts by weight of the aqueous polyether fluidizing agent used in Example 1 and 100 parts by weight of this powder mixture
0.8 parts by weight was kneaded in the same manner as in Example 1 to prepare a self-leveling material, and its properties were measured in the same manner as in Example 1. Table 1 shows the results.

The cement composition containing silica sand to which the polyether-based fluidizing agent has adhered not only exhibits good initial fluidity but also has a small decrease in fluidity with time. Also, by adding only water, the excellent flow characteristics can be exhibited. On the other hand, those containing no polyether-based fluidizer have extremely low fluidity and are far from practical. Also,
When the polyether-based fluidizer was added at the time of mixing with water, in the strictly controllable small-scale experiment shown here, the polyether-based fluidizer was previously deposited as far as fluidity was concerned. It shows the same value as that when silica sand is used, but this is equivalent to factory kneading where strict component control is possible, and it is not effective in improving workability at the construction site, as described above However, it is not an essential solution to the problem.

[0022]

According to the method of the present invention, a powdery self-leveling cement composition can be obtained very easily. Further, the powdery self-leveling cement composition obtained by the method of the present invention is excellent in initial fluidity, in addition to the simplicity of providing a self-leveling material by simply adding water and kneading at the construction site, and having excellent initial fluidity. Since the deterioration of the properties with time is small, the workability is extremely excellent, and its utility value is high.

Claims (5)

[Claims] 1. A powdery self-leveling cement composition comprising cement and silica sand having a polyether-based fluidizing agent adhered to its surface. 2. The silica sand has an average particle size of 50 to 500 μm.
The powdery self-leveling cement composition according to claim 1, wherein a silica sand having a range of (1) is used. 3. The powdery self-leveling cement composition according to claim 1, wherein the amount of the polyether-based fluidizing agent is 0.1 to 100 parts by weight based on 100 parts by weight of silica sand. 4. The proportion of cement represented by (cement) / [(cement) + (silica sand having a polyether-based fluidizing agent adhered to its surface)] is in the range of 55 to 65% by weight. The powdery self-leveling cement composition according to any one of claims 1 to 3. 5. A silica sand treated with an aqueous solution of a polyether-based fluidizing agent, dehydrated and dried to obtain silica sand to which the polyether-based fluidizing agent has adhered, and the silica to which the polyether-based fluidizing agent has adhered. A method for producing a powdery self-leveling cement composition, comprising mixing sand and cement.