JPH0336775B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to novel cementitious self-leveling compositions. Conventionally, the floors of concrete buildings have been difficult to avoid when concrete is poured, resulting in steps and unevenness, resulting in poor surface precision, and interior work such as floor tiling or carpeting has been carried out directly on such floors. Therefore, methods to improve surface accuracy include smoothing the surface with a metal trowel while it is semi-hardened after pouring, or applying additional mortar on top of the concrete and finishing with a metal trowel. It is being said. However, this kind of construction method is
This method is undesirable because it requires labor and is complicated, and there are also time constraints for selecting concrete and mortar conditions suitable for finishing. For this reason, a method of casting a material that naturally forms a smooth horizontal surface, that is, a self-leveling material, on the surface of poured concrete has recently come into use. Gypsum is the most commonly used self-leveling material, but
This has the drawbacks of insufficient mechanical strength, low hardness, and insufficient water resistance. Another method is to use cement mortar or cement paste, but in order to provide self-leveling properties, it is necessary to increase the water ratio, and even if a water reducing agent is used, breathing or cracking may occur. etc., the surface condition is poor,
Furthermore, the adhesion strength to the base was insufficient, and the results were not satisfactory. The present invention provides a self-leveling composition which solves these problems, and which comprises adding (a) hydrophobic groups having 8 or more carbon atoms per 100 parts by weight of cement to cement mortar or cement paste.
Modified polyvinyl alcohol with 0.01-5 mol%
The present invention relates to a cement-based self-leveling composition containing 0.1 to 10 parts by weight and (b) 0.01 to 10 parts by weight of a water reducing agent, and further includes (c) an antifoaming agent together with the components (a) and (b). It relates to a self-leveling composition containing 0.1 to 5 parts by weight. When the cementitious self-leveling composition of the present invention is cast onto a concrete floor surface,
Spreads evenly to form a smooth horizontal surface, causing no breathing or cracking.
It also has good adhesion to the underlying concrete,
The composition itself has excellent properties such as good strength of the cured product. These characteristics are described above (a)
This is due to the synergistic effect of the component and (b) component, and was discovered for the first time through research by the present inventors. To explain this, the self-leveling composition of the present invention is mainly composed of cement mortar or cement paste, and the cements used therein include ordinary, early strength and ultra early strength Portland cements, slag cements, and alumina cements. Any known hydraulic cement such as cement can be used. (a) Modified polyvinyl alcohol added to cement mortar or cement paste is said to contain 0.01 to 5 mol% of hydrophobic groups having 8 or more carbon atoms. Flow characteristics cannot be obtained. Examples of hydrophobic groups having 8 or more carbon atoms include vinyl ethers such as lauryl vinyl ether, cetyl vinyl ether, and stearyl vinyl ether, vinyl tertiary carboxylates having 9 to 11 carbon atoms (product name: Beopa, etc.), α-decene, α
Examples include unsaturated hydrocarbons such as -dodecene, α-heptadecene, and α-octadecene, and straight chain fatty acid vinyls such as vinyl laurate and vinyl stearate. Among these, especially vinyl ethers,
Unsaturated hydrocarbons and vinyl tertiary carboxylates are preferred. The content of these hydrophobic groups in the modified polyvinyl alcohol is preferably 0.01 to 5 mol%, particularly 0.05 to 5 mol%. This is because if it is less than 0.01 mol %, there is no effect of introducing hydrophobic groups, and if it is more than 5 mol %, it is unfavorable in terms of water solubility. In the present invention, mol % indicating the content of hydrophobic groups is the ratio of the number of hydrophobic group-bonded monomer units to the total number of monomer units constituting the polymer molecule. In addition to the above-mentioned hydrophobic group, the modified polyvinyl alcohol (a) used in the present invention may contain other substituents within the range that does not impair its properties. In particular, it may be a partially saponified product containing an acetyl group, and partially saponified modified polyvinyl alcohol is preferable from the viewpoint of solubility. The amount of component (a) to be blended is required to be in the range of 0.1 to 10 parts by weight per 100 parts by weight of cement. If it is less than 0.1 parts by weight, there is no effect, and if it is more than 10 parts by weight, fluidity will be inhibited. Next, (b) water reducing agents to be blended with component (a) include lignin sulfonate and its derivatives;
Polyoxyethylene alkyl allyl ether, oxycarboxylate and its derivatives, alkylaryl sulfonate, polyol complex, methylol melamine sulfonate, etc., or various products containing these as main ingredients and containing surfactants etc. Any known products such as commercially available products can be used. The appropriate amount of these water reducing agents is 0.01 to 10 parts by weight per 100 parts by weight of cement. In addition to the above ingredients, the composition of the present invention may include
(c) It is preferable to incorporate an antifoaming agent, and it is particularly desirable to add an antifoaming agent when a partially saponified product is used as the component (a). Examples of antifoaming agents include polyoxyethylene/polyoxypropylene block copolymers, polyoxyethylene fatty acid esters, polyoxyethylene alkyl ethers, ethylenediamine polyoxyethylene polyoxypropylene adducts, higher alcohols, silicones, tributyl phosphate, and other known antifoaming agents. can be used. The appropriate amount of these antifoaming agents is 0.1 to 5 parts by weight per 100 parts by weight of cement. The cementitious self-leveling composition of the present invention includes the above-described components (a), (b), and, if necessary, (c) in cement mortar or cement paste.
It can be obtained by adding ingredients to make a uniform composition, but it can also be used in various emulsions, latex,
There is no problem in adding thickeners, curing accelerators, fillers, waterproofing agents, coloring agents, etc. The composition of the present invention is made fluid by mixing with water, and it is sufficient to cast it onto the concrete floor surface.In this case, it is also possible to apply by pump-up, which allows for good fluidity. properties, surface smoothness, adhesive, strength, and hardness. The composition of the present invention can be used not only for floor surfaces, but also for forming surfaces during the production of concrete and cement secondary products. Tiles such as vinyl chloride tiles, carpets, etc. can be directly applied to the surface formed by the composition of the present invention. Next, specific examples will be given. Example 1 Various additives shown in Table 1 were dissolved or dispersed in an appropriate amount of water and added to 100 parts by weight of ordinary Portland cement and 300 parts by weight of river sand (3 mm or less), and further water was added and kneaded to obtain a flow value of 320 mm. (JIS flow cone used, no impact) (Composition No.
1-6). Each of the self-leveling compositions thus produced was cast onto a concrete floor surface with an uneven area of about ±10 mm and an area of 1.6 m ² to an average thickness of about 30 mm, and left to harden. Various physical properties were measured 28 days after casting, and the results were as shown in Table 2.

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【table】

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[Table] * Comparative Experiment Example 2 Ordinary Portland cement 100 parts by weight, degree of polymerization
1450, modified polyvinyl alcohol 5 with saponification degree of 97.5 mol% and containing 1 mol% of lauryl vinyl ether
Parts by weight, alkylaryl sulfonate (mighty)
100) 0.5 parts by weight, silicone antifoaming agent 0.7 parts by weight,
A cement paste mixed with 57 parts by weight of water was cast onto a concrete floor with an uneven surface of ±5 mm and an area of 1.6 m ² to an average thickness of about 15 mm, and left to harden. Adhesion to the substrate was good, and a smooth horizontal surface with no cracks was obtained. On the other hand, for comparison, when we applied the same cement paste as above except that no additive was added, the cement paste had poor flowability and did not spread on the floor surface. When the amount of water was increased to 75 parts by weight, the fluidity became good, but many cracks occurred after curing, and the adhesion to the substrate was poor. Furthermore, when the amount of modified polyvinyl alcohol added was 12 parts by weight in the above, fluidity was poor. In this case, when the amount of water was increased to 80 parts by weight, the fluidity became good, but cracks occurred after curing.

Claims (1)

[Scope of Claims] 1. Per 100 parts by weight of cement, (a) 0.1 to 10 parts by weight of modified polyvinyl alcohol having 0.01 to 5 mol% of hydrophobic groups having 8 or more carbon atoms and (b) a water reducing agent to cement mortar or cement paste. A cementitious self-leveling composition containing 0.01 to 10 parts by weight. 2. A cement-based self-leveling composition comprising the composition according to claim 1 containing (c) 0.1 to 5 parts by weight of an antifoaming agent per 100 parts by weight of cement. 3. The cement-based self-leveling composition according to claim 1 or 2, wherein the modified polyvinyl alcohol is a saponified product of a copolymer of vinyl acetate and alkyl vinyl ether. 4. The cement-based self-leveling composition according to claim 1 or 2, wherein the modified polyvinyl alcohol is a saponified product of a copolymer of vinyl acetate and an unsaturated hydrocarbon. 5. The cement-based self-leveling composition according to claim 1 or 2, wherein the modified polyvinyl alcohol is a saponified product of a copolymer of vinyl acetate and vinyl tertiary carboxylate.