JP2951374B2 - Cement admixture and cement composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cement admixture and a cement composition for providing a high-strength polymer cement excellent in fluidity, adhesion and crack resistance, and its industrial application. The fields are diverse such as mortar and concrete, repair materials, flooring materials, waterproofing materials, adhesives and building materials, which are solid and durable.

(Conventional technology and its problems) In recent years, durability of concrete structures has become a problem, and there is a demand for reliable supplies of concrete and repair materials.

However, in concrete structures, carbon dioxide gas generally penetrates from the concrete surface, and the reinforcing steel corrodes due to the decreasing pH inside the concrete.

Reinforcing bars are corroded by chlorine ions that enter the concrete from the outside.

Abnormal expansion occurs due to the reaction between the SiO ₂ in the aggregate and the alkali eluted from the cement.

Reinforcing bars are corroded by sea sand used as aggregate.

For example, there is a problem that the durability of the concrete structure is reduced.

On the other hand, as a method of increasing the durability of concrete itself and a method of repairing a deteriorated structure, a method of casting a polymer cement for repair has been studied.

That is, as a method of increasing the durability of concrete itself, conventionally, a water-reducing agent known as a cement admixture for reducing the water-cement ratio and ensuring fluidity,
As a particularly effective one, a β-naphthalene sulfonate condensate-based water reducing agent has been used.

However, when cracks occur, harmful ions penetrate therefrom, resulting in deterioration, which is inferior in terms of durability, and it has been desired to provide dense concrete which is less likely to crack.

In addition, as a method of repairing a deteriorated structure by casting a polymer cement for repair, the concrete of the corroded portion of the reinforcing bar is scraped off, and after performing the rust prevention treatment of the reinforcing bar,
In order to improve the adhesive strength of the base material to concrete, to prevent cracking of the repair part of the thin layer and to improve the bending strength of the repair mortar and to impart elasticity, various polymers, for example, acrylic, polystyrene, Methods such as casting a repair polymer cement using a polymer such as vinyl acetate, vinylidene chloride, vinyl chloride, styrene-butadiene, and chloroprene have been studied.

However, with conventional polymer cement, it is necessary to increase the water cement ratio in order to ensure fluidity,
As a result, the hardened body structure using the polymer cement becomes coarse, has a high permeation rate of harmful gas and chlorine, and cannot sufficiently prevent corrosion of the reinforcing steel inside the concrete, which is insufficient for repair. Was.

On the other hand, a polymer has been conventionally added as a material having good adhesive strength and crack resistance.

However, for example, when an ethylene-vinyl acetate-based synthetic resin emulsion using a water-soluble polymer such as polyvinyl alcohol is used as an emulsion stabilizer, β-naphthalenesulfonic acid has excellent crack resistance and adhesiveness. It has been very difficult to ensure the fluidity of mortar and concrete with a reduced water-cement ratio by adding a salt condensate. In addition, when a styrene-butadiene-based synthetic rubber latex, an acrylic-based synthetic resin emulsion, and a vinylidene chloride-based synthetic resin emulsion are used, there are problems such as poor fluidity, but poor adhesion and cracking resistance.

As described above, it has been difficult to supply a cement admixture or a cement composition that provides a high-strength polymer cement excellent in fluidity, adhesiveness, denseness, and crack resistance.

The present inventors have conducted various studies to solve the above problems, and as a result, by using a specific polymer together with a dispersant, a high-strength polymer cement composition excellent in fluidity, adhesion, denseness and crack resistance. The inventor has found that it is possible to provide a product, and has completed the present invention.

(Means for Solving the Problems) That is, the present invention provides an ethylene-vinyl acetate copolymer-based synthetic resin emulsion and a styrene-butadiene copolymer-based synthetic rubber latex using a dispersant and a surfactant as an emulsion stabilizer. And / or a cement admixture mainly containing a polymer containing a mixture of a vinylidene chloride-based synthetic resin emulsion, and a cement composition mainly containing a cement substance and the cement admixture.

 Hereinafter, the present invention will be described in more detail.

As the dispersant according to the present invention, those containing a salt of a naphthalenesulfonic acid formalin condensate, a salt of a melaminesulfonic acid formalin condensate, a ligninsulfonate, a high molecular weight ligninsulfonate and a polycarboxylate as a main component Is mentioned.

As a salt of the naphthalenesulfonic acid formalin condensate, a condensate of sodium β-naphthalenesulfonate is a generally well-known dispersant, and is usually added to cement to improve fluidity. The effect of improving the fluidity is significant even in combination with the polymer in the present invention.

Dispersants such as salts of melamine sulfonic acid formalin condensates other than naphthalene sulfonic acid formalin condensates, lignin sulfonates, high molecular weight lignin sulfonates and polycarboxylates can also improve fluidity in combination with polymers. It is possible.

A salt of a naphthalenesulfonic acid formalin condensate;
The effect of improving fluidity can be naturally obtained even when two or more salts of melamine sulfonic acid formalin condensate, lignin sulfonate, high molecular weight lignin sulfonate, polycarboxylate and the like are used in combination.

The naphthalenesulfonic acid formalin condensate is generally used as an alkali metal salt, an alkaline earth metal salt and an ammonium salt, and specific examples thereof include sodium β-naphthalenesulfonate and calcium β-naphthalenesulfonate.

Examples of commercially available products include Denka FT-500 (trade name, manufactured by Denki Kagaku Kogyo Co., Ltd.) and Cell Flow-10P (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

As a salt of melamine sulfonic acid formalin condensate,
Nippon Sika Co., Ltd.'s product name "Sikamento-FF" and Showa Denko Co., Ltd.'s product name "Sanflow K" by Sanyo Kokusaku Pulp Co., Ltd. G ".

Examples of the high molecular weight lignin sulfonate include “Ultrazine” (trade name, manufactured by Volgard).

As the polycarboxylate, Nippon Shokubai Kagaku Kogyo Co., Ltd. product name "600" obtained by adding an alkyleneimine and / or an alkylene oxide to a carboxy group-containing polymer.
S ", a hydrolyzate of an olefin and an ethylenically unsaturated dicarboxylic anhydride copolymerized by Nippon Zeon Co., Ltd. under the trade names" Work 500 "and" M-10 ". A hydrolyzate such as a copolymer of maleic acid or a copolymer of styrene or other copolymerizable monomer with maleic anhydride. And a sustained-release type.

These can be added as a powder or as a liquid.

The polymer according to the present invention is a mixture of an ethylene-vinyl acetate copolymer-based synthetic resin emulsion and a styrene-butadiene copolymer-based synthetic rubber latex.
It is a mixture of a vinyl acetate copolymer-based synthetic resin emulsion, a vinylidene chloride-based synthetic resin emulsion, and a vinylidene chloride-based synthetic resin emulsion.

Usually, when a synthetic resin emulsion is produced by emulsion polymerization, a water-soluble polymer such as poval (PVA) or hydroxyethyl cellulose (HEC) which acts as a protective colloid as an emulsion stabilizer may be added. When a water-soluble polymer is used as an emulsion stabilizer, the fluidity is adversely affected. Therefore, in the present invention, a surfactant is used as an emulsion stabilizer, or the fact that a water-soluble oligomer formed in a polymerization process acts as an emulsion stabilizer is used. For this purpose, it is effective to increase the concentration of the polymerization initiator.

As the surfactant, sodium vinyl sulfonate, sodium styrene sulfonate, 2
Sodium sulfoethyl methacrylate, sodium allylalkyl sulfosuccinate, sodium salt of higher alcohol sulfates and ammonium salt of polyoxyethylene alkyl phenyl ether sulfate as cationic, such as 2-aminoethyl methacrylate hydrochloride and 2-hydroxy-3- Examples of the nonionic trimethylaminopropyl methacrylate chloride include polyoxyethylene methacrylate, polyoxyethylene polyoxypropyl ether, polyoxyethylene nonyl phenyl ether, and polyoxyethylene styryl phenyl ether.

The amount of the surfactant used is preferably about 0.01 to 10 parts by weight based on 100 parts by weight of the synthetic resin emulsion. If the amount is less than 0.01 part by weight, it is difficult to carry out emulsion polymerization. If the amount exceeds 10 parts by weight, the weather resistance, alkali resistance, water resistance and the like of the synthetic resin emulsion tend to be adversely affected.

Persulfates such as potassium persulfate as polymerization initiators,
Examples include hydrogen peroxide and various organic peroxides, 4,4'-azobis-cyanovaleric acid having a carboxyl group, and 2,2'-azobisisobutylamidin salt having an amino group.

The amount of the polymerization initiator used is preferably about 0.1 to 1 part by weight based on 100 parts by weight of the solid content of the polymer. If it is less than 0.01 part by weight, it is difficult to carry out emulsion polymerization, and if it exceeds 1 part by weight, the weather resistance, alkali resistance, water resistance and the like of these polymers tend to be adversely affected.

The particle size of the solid content of the polymer thus obtained is
It is about 0.05-5 μm.

The synthetic rubber latex according to the present invention is a styrene-butadiene copolymer (SBR) synthetic rubber latex using a surfactant as an emulsion stabilizer.

The amount of the surfactant used as the emulsion stabilizer is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the solid content of the styrene-butadiene copolymer-based synthetic rubber latex. 0.0
If it is less than 1 part by weight, it is difficult to perform emulsion polymerization, and 10
If the amount is more than 10 parts by weight, the pressure resistance, alkali resistance and water resistance of the styrene-butadiene copolymer-based synthetic rubber latex tend to be adversely affected.

The type of the polymerization initiator and the like are the same as those in the case of the synthetic resin emulsion described above.

The mixing ratio of the synthetic resin emulsion using a surfactant as an emulsion stabilizer and the synthetic rubber latex is 90/10 to 25/75 at the respective solid content ratios in view of excellent compatibility and storage stability as an emulsion. preferable. If it exceeds 90/10, it is difficult to obtain further flow characteristics, and 25/75
If it is less than 30, adhesiveness and crack resistance tend to be poor.

The polymer cement composition of the present invention comprises a hydraulic substance and the above-mentioned cement admixture as main components.

The hydraulic substance according to the present invention is mainly composed of a cementitious substance.

Examples of the cementitious substance include various portland cements such as ordinary / early high strength / ultra early strength and white color, ultra-rapid hardening cement and alumina cement.

Examples of ultra-rapid hardening cement include Onoda Cement Co., Ltd. product name “Jet Cement” and Denki Kagaku Kogyo Co., Ltd. product name “DENKA SUPER CEMENT”, and alumina cement manufactured by Denki Kagaku Kogyo Co., Ltd. The trade names include "Denka Alumina Cement No. 1" and "Denka Alumina Cement No. 2".

When using alumina cement as a cementitious substance, it is preferable to use a hardening modifier together with a dispersant.

Here, as the curing regulator, various sulfates, nitrates,
Carbonate, lithium salt, inorganic salt such as CaCl ₂ , Ca (O
H) ₂ , one or more of inorganic substances such as borax and boric acid, and organic acids or salts thereof such as citric acid, tripolyphosphoric acid, pyrophosphoric acid, tartaric acid and gluconic acid can be used.

The amount of the setting modifier used is preferably 0.005 to 2 parts by weight based on 100 parts by weight of the cementitious substance.

In addition, in the present invention, moderate heat cement, low heat cement such as blast furnace cement and fly ash cement, sulfate resistant cement, high sulfate slag cement, improved blast furnace cement, ultra low heat cement and the like can be used. If a proper curing method is used, calcium hydroxide or calcium oxide can be used.

It is also possible to use cement containing blast furnace slag and fly ash in addition to ordinary mixed cement.

Usually, the particle diameter of the cementitious substance is 5 to 30 μm, but it goes without saying that smaller or larger particles can be used as long as they have hydraulic properties.

In the present invention, it is also possible to use various cement admixtures or cement admixtures such as rapid hardening materials, expanding materials and high-strength admixtures, which are usually used for cement concrete.

Examples of the hardened material include Denka Tomic and Decan Cosmic, trade names of Denka Kagaku Co., Ltd., and Denka CSA # 2 manufactured by Denki Kagaku Co., Ltd.
"0" and other high-strength admixtures include Denki Kagaku Kogyo Co., Ltd.
Product name “DENKA II-1000” and the like.

In the present invention, it is possible to obtain a composite material that can be used as a low water cement ratio by combining the cementitious substance with an inorganic ultrafine powder.

The ultra-fine powder used in the present invention is one finer than cementitious material.
The particles are small in order, preferably two orders of magnitude, and more preferably have an average particle size of 1 μm or less.

There is no particular limitation on the components constituting the ultrafine powder, but those which are easily soluble in water are not suitable, and those which produce a reaction product with calcium hydroxide or the like are preferable.

The method for producing the ultrafine powder may be any method such as a liquid phase, a gas phase, a pulverization, a classification and a combination thereof, and is not particularly limited. Silica dust (silica fume), silica dust, and the like, which are produced in the gas phase as by-products and are by-products during the production of silicon, silicon-containing alloys, zirconia, and the like, are effective. In addition, calcium carbonate, silica gel, opal silica, titanium oxide, aluminum oxide, zirconium oxide, various glasses, clay minerals such as bentonite and their calcined products, amorphous aluminosilicate, chromium oxide, activated carbon, blast furnace slag and fly ash Ultra fine powder can be used.

The amount of ultrafine powder used is 100 parts by volume of the cementitious substance, in terms of fluidity, denseness and high strength properties of the kneaded material.
It is preferably 5 to 100 parts by volume, more preferably 10 to 50 parts by volume. If the amount is less than 5 parts by volume, it is difficult to obtain further high strength properties, and if it exceeds 50 parts by volume, it is difficult to obtain good fluidity, and the friction resistance and strength characteristics of the cured body surface become insufficient. Tend.

In the case of improving the durability, a slight effect appears even when the volume is less than 5 parts by volume.

The cement admixture of the present invention comprises a dispersant, an ethylene-vinyl acetate copolymer-based synthetic resin emulsion using a surfactant as an emulsion stabilizer, a styrene-butadiene copolymer-based synthetic rubber latex, and / or a vinylidene chloride-based synthetic resin. Although the main component is a polymer containing a mixture of emulsions, the amount of the polymer used in the cement admixture is preferably 2 to 25 parts by weight as a solid content with respect to 100 parts by weight of the hydraulic substance, 3-20 parts by weight are more preferred. If it exceeds 25 parts by weight, high strength properties are poor, and if it is 2 parts by weight or less, adhesiveness and crack resistance tend to be poor.

When a polymer and a hydraulic substance are mixed, air bubbles are entrained, and the strength and denseness of the cured product may be reduced. for that reason,
It is preferred to use an antifoaming agent in combination.

Here, examples of the antifoaming agent include fats and oils such as sesame oil, fatty acids such as stearic acid, alcohols such as octyl alcohol, polyhydric alcohols such as sorbitan fatty acid listel and partial esters of fatty acids, and polyoxyethylene polyoxypropylene ether. , Paraffin and silicone.

Commercially available products include silicone-based Toshiba Silicone Co., Ltd. product name “TAS 732”, alcohol-based Sanyo Kasei Kogyo Co., Ltd. product name “Caralin 302”, and polyoxyethylene polyoxypropylene ether-based Toho Chemical ( stock)
The product name “Pronal 502” and the product name “Anti-Hall E-20” manufactured by Kao Corporation are listed.

The amount of the defoamer used is preferably about 1 to 5 parts by weight based on 100 parts by weight of the solid content of the polymer.

The amount of dispersant used is 100 parts by weight of hydraulic substance,
It is preferably from 0.2 to 5 parts by weight, more preferably from 0.2 to 4 parts by weight. If it is less than 0.2 parts by weight, it is difficult to obtain good fluidity, and if it exceeds 4 parts by weight, there is a tendency that no more fluidity can be obtained.

It should be noted that the amount of water to be kneaded is preferably smaller for the purpose of the present invention with respect to the hydraulic substance. Using a cementitious substance and ultrafine powder as a hydraulic substance, further, a dispersant having a main component of naphthalenesulfonic acid formalin condensate, 100 parts by weight of the hydraulic substance, when 1 to 3 parts by weight is added The amount of water used is preferably 45 parts by weight or less with respect to 100 parts by weight of the hydraulic substance, from the viewpoint of ensuring very good fluidity. When the amount of water is 45 parts by weight or less, the strength and the compactness are further improved, and the diffusion coefficient and the water permeability of the chloride ion also have extremely small values. Further, in combination with the ultrafine powder, good fluidity can be ensured even when the amount of water is 30 parts by weight or less or 28 parts by weight or less.

In the present invention, an aggregate having a larger particle diameter can be used in combination with the above-mentioned material.

In the present invention, the aggregate refers to a particle having a particle size exceeding 100 μm, and general sand, gravel, lightweight aggregate, and the like can be used. Further, Mohs hardness is 6 or more or Knoop indenter hardness is 70.
Of course, it is also possible to use a hard aggregate selected on the basis of 0 kgf / mm ² or more. In addition, other materials such as glass and metal can also be used as aggregates.

Usually, the use amount of these aggregates is preferably about 1,000 parts by weight based on 100 parts by weight of the hydraulic substance. However, this does not apply to special construction methods such as the prepacked construction method and the Boston backed construction method.

There is no particular limitation on the kneading method and the charging order of each of the above-mentioned materials, as long as these materials are uniformly kneaded.

The kneaded material can be constructed by pouring or ironing.

Further, in the present invention, it is also possible to combine the above-mentioned material with a reinforcing material such as a steel frame or a reinforcing bar, a fiber, or the like to reinforce the material by tension or bending.

As the fibers, fibers obtained by chattering of cast iron, metal fibers such as steel fibers and stainless steel fibers, various natural or synthetic mineral fibers such as asbestos and ceramic fibers, synthetic resin fibers such as polypropylene and alumina fibers, carbon fibers, and more. , Glass fiber and the like.

It is also possible to use a steel rod or a molded body of alumina fiber which has been conventionally used as a reinforcing material. Particularly, a large molded product often requires such a reinforcing material.

The curing of the high-strength polymer cement kneaded material obtained in this way is not particularly limited, but it is preferable to perform wet curing at the beginning and then dry curing.

The cured product of the present invention is JIS
The method of testing R 5201, shows the compressive strength of 300kgf / cm ^2, 20 ℃, humidity of 60% at 28 days curing, the test method JIS A 6916, shows a 10 kgf / cm ² or more bonding strength.

Uses of the high-strength polymer cement of the present invention include durable concrete structures, or repair materials such as grout of delaminated portions of concrete structures or rust-proof coatings of corroded reinforcing bars, pavement materials such as roads and floor materials, Waterproofing materials such as roof slabs, adhesives for tiles, decorative finishing materials, chemical factory floors, anticorrosion materials such as jointing materials for acid-resistant tiles, and deck covering materials are various.

(Examples) Hereinafter, the present invention will be further described with reference to examples.

Example 1 An ethylene-vinyl acetate copolymer-based synthetic resin emulsion was manufactured and manufactured by Takeda Pharmaceutical Co., Ltd. under the trade name “Crosslen CM”.
X ", a styrene-butadiene copolymer-based synthetic rubber latex and" Aron D-9907 "manufactured by Toa Gosei Chemical Co., Ltd.
A polymer was prepared together with the vinylidene chloride-acrylic copolymer-based synthetic resin emulsion described above, and a high-strength polymer cement mortar was kneaded using the composition shown in Table 1. The results are shown in Table 1.

<Measurement method> Compressive strength: Measured according to JIS R 5201 Adhesive strength: Measured according to JIS A 6916 Crack resistance: Center width 1cm, both end widths 5cm, length 20c
Mortar was poured into a gourd-shaped iron mold having a thickness of 1 cm and a thickness of 1 cm, and cracks were observed.

<Materials> Cement: Onoda Cement Co., Ltd. product name "Onoda White Cement", specific gravity 3.14 Ultrafine powder: silica fume, average particle size 0.2 μm by transmission electron microscope Aggregate: Hisago Sangyo Co., Ltd. product name No. 7 silica sand ”Defoaming agent: TSA 73, manufactured by Toshiba Silicone Co., Ltd.
2) Dispersant: Product name "Cell Flow" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.
110P "Salt of main component naphthalenesulfonic acid formalin condensate Polymer A: Ethylene-vinyl acetate copolymer emulsion-, ethylene: vinyl acetate: normal butyl acrylate = 16:42:42, solid content 50% by weight Emulsion stabilizer is nonionic Of polyoxyethylene nonyl phenyl ether to 100 parts by weight of comonomer
Parts by weight were added. Water, vinyl acetate, normal butyl acrylate, and an emulsifier stabilizer were charged into a stainless steel autoclave, and the temperature was raised to 60 ° C. while stirring, and then ethylene was supplied at a predetermined pressure.

Then ammonium persulfate was added to initiate polymerization,
After the polymerization was carried out until the residual monomer became 0.5% by weight or less, the mixture was cooled to obtain a synthetic resin emulsion.

Polymer B: ethylene-vinyl acetate copolymer emulsion-
Ethylene: vinyl acetate = 20:80, solid content 50% by weight.

Emulsion stabilizer is polyvinyl alcohol comonomer 100
5 parts by weight were added to parts by weight.

Water, vinyl acetate and an emulsion stabilizer were charged into a stainless steel autoclave, and a synthetic resin emulsion was obtained in the same manner as in Polymer A.

Polymer C: Styrene-butadiene copolymer latex, trade name "Crosslen CMX" manufactured by Takeda Pharmaceutical Co., Ltd. Analysis results by IR, NMR and PGC are styrene: butadiene = 54: 46, emulsifier is sodium stearate. Polymer D: chloride Vinylidene copolymer latex, trade name "Aron D-9907" manufactured by Toa Gosei Chemical Co., Ltd. IR, NMR and PGC
Analysis showed that vinylidene chloride: normal butyl arylate = 81:19 and the emulsion stabilizer was polyoxyethylene alkyl phenyl ether (Effect of the Invention) By using the cement admixture of the present invention, it has become possible to provide a high-strength polymer cement composition excellent in fluidity, adhesiveness, denseness and crack resistance.

Claims (2)

(57) [Claims] 1. A mixture of an ethylene-vinyl acetate copolymer-based synthetic resin emulsion, a styrene-butadiene copolymer-based synthetic rubber latex and / or a vinylidene chloride-based synthetic resin emulsion using a dispersant and a surfactant as an emulsion stabilizer. Cement admixture containing a polymer containing as a main component. 2. A cement composition comprising a hydraulic substance and the cement admixture according to claim 1 as main components.