JP2003252667A - Latex for resin mortar and resin mortar composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a latex having no working problem because the blending stability of a resin mortar composition which contains cement and a filler, is good and easy to work just after blended material painting because leather spreading is not exhibited just after the painting, and furthermore having a good following property and good adhesiveness to underside concrete as the flexibility of a cement hardened product is good. <P>SOLUTION: The latex obtained by emulsion polymerization of a specific component monomer and which has a specific structure is combined with the cement and the filler. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a latex for resin mortar used as a waterproof material, a repair material, a nursing material, a finishing material for buildings in the field of civil engineering and construction, and a composition thereof. Specifically, in a resin mortar composition containing cement and a filler, there is no problem in workability due to good compounding stability, and since there is no skinning due to the latex component immediately after application, work immediately after application To provide a latex that is easy to process. Furthermore, since the hardened cement product has good flexibility, it has good followability to the underlying concrete and good adhesion.

[0002]

2. Description of the Related Art In the field of civil engineering and construction, cement,
Mortar compositions containing fillers such as silica sand are used for waterproofing of buildings, makeup, repairing and finishing of surfaces such as inner and outer walls. This conventionally known mortar composition has a drawback that cracks easily occur after curing. The causes are, for example, due to shrinkage of the mortar itself, external changes such as temperature change and freeze-thawing, and crack occurrence in the base concrete. There are many problems that cracks occur, such as water entering from the cracks that cause water leakage, facilitating carbonization of concrete and rusting of reinforcing bars, and promoting cracking of concrete. Was holding.

In order to solve these problems, a resin mortar composition is known in which a polymer is added to the mortar composition. This resin mortar composition is a combination of cement and a filler containing aggregate, various latex,
A polymer such as an emulsion is added. The system to which this latex is added is effective for improving the performance such as the adhesive strength with the base skeleton, the waterproof performance, the prevention of dryout, and the care of the base concrete. However, there is a problem in that the resin mortar composition itself does not have sufficient followability to shrinkage of the base mortar composition or the occurrence of cracks in the base concrete, and cracks are more likely to occur as the thickness of the resin mortar composition increases.

On the other hand, in Japanese Patent Laid-Open No. 59-13686, an emulsion containing an acrylic polymer having a film elongation of 1500% or more and a glass transition temperature of -10 ° C. or less is added to a mortar formulation. A technique of making a cement hardened product into rubber-like high elasticity is disclosed. The disclosed technology improves the occurrence of cracks in the mortar itself and also makes it possible to follow the underlying concrete. Also,
Japanese Patent Laid-Open No. 63-55143 discloses a technique of adding an emulsion obtained by using a specific monomer composition with a nonionic emulsifier to a mortar formulation. The disclosed technique imparts elasticity to the mortar after curing, prevents cracks, and has good followability with the underlying concrete.

Although these disclosed techniques improved the prevention of cracks in the resin mortar itself and the ability to follow the underlying concrete, there was a problem with the stability of the latex during cement formulation. Workability is poor, and further, skinning occurs due to the latex component immediately after coating, causing stickiness and stickiness on the coating surface, which is a practical problem such as hindering the next work. .

Further, JP-A-58-49653, JP-A-3-205333, and JP-A-2000-1780.
Japanese Patent Publication No. 55 discloses a latex for cement admixture having a core-shell structure. However, JP-A-5
No. 8-49653 and JP-A No. 2000-178055 have a high glass transition temperature on the shell side and are effective for suppressing skinning and the like, but the flexibility of the resin mortar cured product is lost and the original purpose is intended. Performance will not be obtained. JP-A-3-20533 discloses a core-shell structure using a specific monomer composition. However, in the composition of the shell side, the mass% of alkyl methacrylate is
It is not sufficient for problems such as stickiness and stickiness on the surface coated with resin mortar. Therefore, it is desired to solve the balance as soon as possible.

[0007]

[Patent Document 1] Japanese Patent Laid-Open No. 59-13686

[Patent Document 2] Japanese Patent Laid-Open No. 63-55143

[Patent Document 3] Japanese Unexamined Patent Publication No. 58-49653

[Patent Document 4] Japanese Unexamined Patent Publication No. 3-205333

[Patent Document 5] Japanese Unexamined Patent Publication No. 2000-178055

[Patent Document 6] Japanese Unexamined Patent Publication No. Sho 58-49653

[Patent Document 7] Japanese Patent Laid-Open No. 2000-178055

[Patent Document 8] Japanese Unexamined Patent Publication No. 3-20533

[0008]

The present invention is a cement,
In the resin mortar composition containing the filler, there is no problem in workability due to good compounding stability, and since skinning due to the latex component does not occur immediately after coating, work immediately after coating is easy. Is. Further, it is an object of the present invention to provide a latex which has good flexibility to the base concrete and good adhesion because the hardened cement product has good flexibility.

[0009]

The present inventor has found that a combination of a latex having a specific structure or a latex having a specific monomer composition, cement, and a filler is effective for solving the above problems. The present invention was found out and the present invention was completed. That is, the present invention is: A multilayer latex (1) having a core portion and a shell portion, wherein the copolymer of the core portion has a glass transition temperature of -30 ° C or lower, and the copolymer of the shell portion has a glass transition temperature of -30 ° C to 1. A latex for resin mortar, which has a temperature of 20 ° C. The latex (1) is at least one monomer selected from aromatic vinyl monomers, methacrylic acid alkyl ester monomers, acrylic acid alkyl ester monomers, hydroxyl group-containing vinyl monomers, 2. A monomer composition containing a nitrile group-containing vinyl monomer and a carboxyl group-containing vinyl monomer, which is obtained by emulsion polymerization. A resin mortar composition containing 5 to 600 parts by mass of the filler (3) and 5 to 150 parts by mass (solid content) of the latex (1) according to claim 1 with respect to 100 parts by mass of the cement (2).

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The latex (1) used in the present invention is a multi-layered latex (1) having a core part and a shell part, wherein the copolymer of the core part has a glass transition temperature of −30 ° C. or lower, The glass transition temperature of the polymer is -3
It is 0 ° C to 20 ° C. When the glass transition temperature of the copolymer of the core portion is -30 ° C or lower, cracking of the resin mortar composition is prevented, and there is no problem in followability with the base concrete.
The glass transition temperature of the copolymer of the shell part is -30 to 20 ° C.
Therefore, the compounding stability of the resin mortar composition is good, and there is no problem with the followability with the base concrete. Preferably,
The glass transition temperature of the copolymer of the core part is −40 ° C. or lower, and the lower limit is preferably −70 ° C. The glass transition temperature of the copolymer of the shell part is preferably −30 to 0.
℃. The multilayer structure latex having a core portion and a shell portion in the present invention, the core of the copolymer of the central portion,
The copolymer outside the core portion is used as the shell portion, and the copolymer further outside the shell portion is also used as the shell portion.

The glass transition temperature of the copolymer referred to herein can be estimated by the following equation from the glass transition temperature of the homopolymer of the monomer and the copolymerization ratio of the monomer. 1 / Tg = W ₁ / Tg ₁ + W ₂ / Tg ₂ + ... Tg: glass transition temperature (° K) W ₁ , W _2, ... Of a copolymer composed of monomers ₁ , ₂ ... Mass fraction of Monomer 1, Monomer 2, ... Where W ₁ + W ₂ + ·· = 1 Tg ₁ , Tg ₂ ···: Homo-weight of Monomer 1, Monomer 2, ··· The Tg (° K) of the monomer homopolymer used for the calculation of the glass transition temperature (° K) of the coalescence is
For example, Polymer Handbook (John Willey
& Sons). Numerical values used in the present application are illustrated. The value in parentheses indicates the Tg of the homopolymer. Polystyrene (373 ° K), polymethylmethacrylate (378 ° K), polybutyl acrylate (219
° K), 2-ethylhexyl polyacrylate (205 ° K), polyacrylic acid (379 ° K), polymethacrylic acid (403 ° K), polyacrylonitrile (373 ° K), 2-hydroxyethyl polyacrylate ( 258 ° K), 2-hydroxyethyl polymethacrylate (328
° K).

The ratio of the core part to the shell part of the latex (1) of the present invention is 5 to 80% by mass for the core part and 20 to 20 for the shell part.
95 mass% is preferable. When the core portion is 5 to 80% by mass, cracking of the resin mortar composition is prevented, and there is no problem in followability with the base concrete. Shell part 20-95% by mass
Therefore, there is no problem in the compounding stability of the resin mortar composition, and there is no problem in the followability with the base concrete. More preferably, the core portion is 10 to 60 mass% and the shell portion is 40 to 90 mass%.

The latex (1) of the present invention comprises at least one monomer selected from aromatic vinyl monomers, methacrylic acid alkyl ester monomers and acrylic acid alkyl ester monomers, and hydroxyl group-containing vinyl monomer. It can be obtained by emulsion polymerization of a monomer composition containing a monomer, a nitrile group-containing vinyl monomer, and a carboxyl group-containing vinyl monomer. Examples of the aromatic vinyl monomer used in the latex (1) of the present invention include styrene and vinyltoluene. Preferred is styrene.

The methacrylic acid alkyl ester monomers include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, methacrylic acid. Examples thereof include 2-ethylhexyl acid and lauryl methacrylate. Further, as the acrylic acid alkyl ester monomer, for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate,
Hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate and the like can be mentioned. Methyl methacrylate is preferred as the methacrylic acid alkyl ester-based monomer, and butyl acrylate and 2-ethylhexyl acrylate are preferred as the acrylic acid alkyl ester-based monomer.

As the hydroxyl group-containing vinyl monomer, for example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, polyethylene glycol acrylate, Examples thereof include polyethylene glycol methacrylate. Preferred are 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate. Further, examples of the nitrile group-containing vinyl-based monomer include acrylonitrile and methacrylonitrile. Acrylonitrile is preferred. Examples of the carboxyl group-containing vinyl monomer include acrylic acid, methacrylic acid, maleic acid or its monoester, fumaric acid or its monoester, itaconic acid or its monoester, and the like. Preferred are acrylic acid, methacrylic acid, and itaconic acid.

The aromatic vinyl monomer used in the latex (1) of the present invention is 5 to 50% by mass based on all monomers. When the aromatic vinyl-based monomer is 5% by mass or more, there is no problem in stickiness of the cured resin mortar, and when it is 50% by mass or less, there is no problem in crackability of the cured resin mortar. It is preferably 10 to 40% by mass. The amount of the methacrylic acid alkyl ester monomer and / or the acrylic acid alkyl ester monomer used in the latex (1) of the present invention is 20 to 90% by mass based on all the monomers. When the amount of the methacrylic acid alkyl ester monomer and / or the acrylic acid alkyl ester monomer is 20% by mass or more, there is no problem in stickiness of the cured resin mortar, and when it is 90% by mass or less, there is a problem in crackability of the cured resin mortar. Absent. Preferably 30-80
It is% by mass.

The hydroxyl group-containing vinyl monomer used in the latex (1) of the present invention is 0.5 to 0.5 out of all monomers.
It is 5% by mass. When it is 0.5% by mass or more, there is no problem in cement mixing stability, and when it is 5% by mass or less, there is no problem in water resistance of the cured resin mortar. It is preferably 1 to 4 mass%. The nitrile group-containing vinyl monomer used in the latex (1) of the present invention is 1 to 10% by mass based on all monomers. When the amount is 1% by mass or more, the resin mortar cured product has no problem of cracking. It is preferably 2 to 8% by mass. The carboxyl group-containing vinyl monomer used in the latex (1) of the present invention is 0.1 to 4% by mass based on all monomers. 0.1
When the content is 4% by mass or less, emulsion polymerization can be carried out without problems, and the water resistance of the resin mortar cured product is satisfactory. It is preferably 0.5 to 3% by mass.

In addition to the above-mentioned monomers, in order to improve various qualities and physical properties required for the latex of the present invention, monomer components other than the above may be used. Examples of those monomers include; amide group-containing monomers such as acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, maleic acid amide, and maleimide; Monomers such as N-methylol acrylamide, N-methylol methacrylamide, dimethylol acrylamide, dimethylol methacrylamide and the like; alkoxymethyl group-containing monomers such as N-methoxymethyl acrylamide and N-methoxymethyl. Methacrylamide, N-butoxymethyl acrylamide, N-butoxymethyl methacrylamide, etc. may be mentioned; epoxy group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether. Methyl glycidyl acrylate, methyl glycidyl methacrylate and the like; polyfunctional monomers such as divinylbenzene, polyoxyethylene diacrylate, polyoxyethylene dimethacrylate, polyoxypropylene diacrylate, polyoxypropylene dimethacrylate, butanediol. Diacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, etc .; silyl group-containing monomers such as vinyltrichlorosilane, vinyltrimethoxy. Silane, vinyltriethoxysilane, tris-2-methoxyethoxyvinylsilane, γ-methacryloxy Examples include propyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and the like; diesters of α, β-ethylenically unsaturated dicarboxylic acids, such as dibutyl maleate, dioctyl fumarate, and the like; vinyl esters, such as Examples thereof include vinyl acetate and vinyl propionate.

In the latex of the present invention, the monomer composition of the core part and the shell part is not particularly limited. Preferably, in the composition of the monomers used for the core part, the aromatic vinyl-based monomer is 1 to 20% by mass, the methacrylic acid alkyl ester-based monomer is 0 to 45% by mass, and the acrylic acid alkyl ester is 50 to 95% by mass of the vinyl-based monomer, 1 to 10% by mass of the vinyl monomer containing the hydroxyl group, 1 to 20% by mass of the vinyl monomer of the nitrile group, and the carboxyl group-containing The vinyl-based monomer is 0 to 4 mass%. In the composition of the monomers used in the shell portion, the aromatic vinyl-based monomer is 5 to 50 mass%, the methacrylic acid alkyl ester-based monomer is 5 to 45 mass%, and the acrylic acid alkyl ester-based monomer is 30-80
% By mass, and the hydroxyl group-containing vinyl monomer is 1
10 to 10% by mass, the nitrile group-containing vinyl-based monomer is 1 to 20% by mass, and the carboxyl group-containing vinyl-based monomer is 0.1 to 4% by mass. In particular, by using the aromatic vinyl-based monomer and the methacrylic acid alkyl ester-based monomer together in the shell portion, there is no problem in stickiness, stickiness, skin-tightness, etc. on the surface coated with the resin mortar.

The latex (1) of the present invention is obtained by an emulsion polymerization method. The emulsion polymerization method is not particularly limited, and a conventionally known method can be used. For example, in a dispersion system containing the above-mentioned monomer, a chain transfer agent, a surfactant, a radical polymerization initiator, and other additive components used as necessary in an aqueous medium as a basic composition component, It can be obtained by polymerizing. In the polymerization, a method of sequentially changing the composition of the monomer composition supplied to form the core portion and the shell portion can be used. For example, a method of polymerizing the core portion and then polymerizing the shell portion in the presence of the core portion, or a method of polymerizing the shell portion and then polymerizing the core portion may be performed. In the case of the present application, the mass% of the carboxyl group-containing vinyl monomer in the monomer composition of the shell part (1-S), and the carboxyl group-containing vinyl monomer in the monomer composition of the core part The relationship with the mass% of (1-C) is preferably (1-S)> (1-C).

The surfactant used in the present invention refers to a compound having at least one hydrophilic group and one or more lipophilic group in one molecule. Examples of the surfactant include anionic interfaces such as aliphatic soap, rosin acid soap, alkyl sulfonate, dialkyl aryl sulfonate, alkyl sulfosuccinate, polyoxyethylene alkyl sulfate, and polyoxyethylene alkyl aryl sulfate. Activator, polyoxyethylene alkyl ether,
Nonionic surfactants such as polyoxyethylene alkylaryl ethers and polyoxyethyleneoxypropylene block copolymers can be mentioned. In addition to these, a so-called reactive surfactant in which an ethylenic double bond is introduced into the chemical structural formula of a surfactant having a hydrophilic group and a lipophilic group may be used.

The method of using the surfactant is not particularly limited,
For example, the entire amount may be used during emulsion polymerization, or the required amount may be added after emulsion polymerization. A preferred use of the surfactant is to use 1 to 10 parts by mass of the nonionic surfactant with respect to 100 parts by mass of the monomer composition. When the amount of the nonionic surfactant is 1 part by mass or more, there is no problem in the compounding stability with the cement, and when it is 10 parts by mass or less, there is no problem in the water resistance of the cured resin mortar.

The polymerization initiator used in the present invention includes
It radically decomposes by heat or a reducing substance to initiate addition polymerization of a monomer, and either an inorganic initiator or an organic initiator can be used. As such a substance, a water-soluble or oil-soluble polymerization initiator can be used. Examples of the water-soluble polymerization initiator include peroxodisulfate, peroxides, water-soluble azobis compounds, and peroxide-reducing agent redox systems, and examples of the peroxodisulfate include potassium peroxodisulfate ( KPS), sodium peroxodisulfate (NPS), ammonium peroxodisulfate (APS), and the like. Examples of peroxides include hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxymaleic acid, and succinic acid peroxide. , Benzoyl peroxide and the like, and examples of the water-soluble azobis compound include 2,2-azobis (N-
Hydroxyethylisobutyramide), 2,2-azobis (2-amidinopropane) dihydrogen chloride, 4,4-azobis (4-cyanopentanoic acid), and the like, and as a redox system of a peroxide-reducing agent, For example, the above-mentioned peroxide is sodium sulfoxylate formaldehyde,
A reducing agent such as sodium bisulfite, sodium thiosulfate, sodium hydroxymethanesulfinate, L-ascorbic acid, and salts thereof, cuprous salts, and ferrous salts can also be used in combination with the polymerization initiator.

The polymerization temperature in this emulsion polymerization is usually 6
It is selected in the range of 0 to 100 ° C., but the polymerization may be carried out at a lower temperature, for example, 20 to 40 ° C. by the redox polymerization method or the like. Further, for example, in the two-stage polymerization, the polymerization temperature in the first stage and the polymerization temperature in the second stage may be the same or different. The particle size of the latex (1) of the present invention is not particularly limited. The particle size control method is, for example,
Seed latex, it can be adjusted by the use ratio of the surfactant, etc. Generally, the higher the use ratio of them, the smaller the average particle size of the latex produced,
On the contrary, the average particle size tends to increase. The seed latex may be polymerized in the same reaction vessel prior to the polymerization of the latex of the present invention, or a seed latex polymerized in a different reaction vessel may be used. The preferred particle size is 50 to 400 nm.

The latex (1) of the present invention may contain the following materials in order to improve the performance. For example,
Water-soluble resins, solvents, plasticizers, defoamers, thickeners, leveling agents, dispersants, coupling agents, colorants, waterproofing agents, lubricants, pH adjusters, preservatives, inorganic pigments, organic pigments, Examples thereof include surfactants and cross-linking agents such as epoxy compounds, polyvalent metal compounds, and isocyanate compounds.

As the cement (2) used in the present invention, for example, JIS R5210 (Portland cement), R5211 (blast furnace cement), R5212 (silica cement), R5213 (fly ash cement).
Standard Portland Cement, Early Strength Portland Cement, Super Early Strength Portland Cement, Moderate Heat Portland Cement, Sulfate Resistant Portland Cement, Blast Furnace Cement, Silica Cement, Fly Ash Cement can be used. Is described in the common sense of cement (issued in March 1994),
Various cements such as special cement, white Portland cement, cement-based solidifying material, alumina cement, ultra rapid hardening cement, colloidal cement, Yui cement, geothermal well cement, expansion cement, and other special cement can be used.

As the filler (3) used in the present invention, sand, silica sand, which is generally used for cement mortar,
Cold water sand, natural and artificial lightweight aggregates, etc. can be used, and inorganic or organic pigments can also be used, for example, inorganic pigments such as magnesium, calcium, zinc, barium, titanium, aluminum, antimony and lead. Examples thereof include oxides, hydroxides, sulfides, carbonates, sulfates and silicic acid compounds. Specifically, for example, calcium carbonate, kaolin, talc, titanium dioxide, aluminum hydroxide, silica, gypsum, barite powder, alumina white, satin white and the like. Examples of organic pigments include fine solid polymer powders such as polystyrene, polyethylene, and polyvinyl chloride.

The amount used in the present invention is 5 to 600 parts by mass of the filler (3) and 5 to 150 parts by mass (solid content) of the latex (1) of the present invention with respect to 100 parts by mass of the cement (2). With more than 5 parts by mass of filler, increase in strength,
There is no problem with cracking due to drying. On the other hand, when the amount is 600 parts by mass or less, there is no problem in strength. It is preferably in the range of 50 to 500 parts by mass. Further, when the latex (1) of the present invention is 5 parts by mass or more, there is no problem in cracking and conformability to the underlying concrete, and when it is 150 parts by mass or less, there is no problem in adhesion and compounding stability of the mortar composition. It is preferably in the range of 10 to 100 parts by mass. More preferably, it is in the range of 20 to 80 parts by mass.

The method of blending the resin mortar composition of the present invention is not particularly limited. The latex, cement and filler may be mixed together or sequentially. The method of applying the resin mortar composition of the present invention is not particularly limited. Any of iron coating, wool roller coating, mastic roller coating, spray coating, roll coater coating and the like may be used.

The resin mortar composition of the present invention is not limited to the above components, and any other components may be added. For example, water reducing agents and superplasticizers (polycarboxylic acid type, melamine sulfonic acid type, naphthalene sulfonic acid type, lignin sulfonic acid type, etc.), shrinkage reducing agents (glycol ether type, polyether type, etc.), cryoprotectants (calcium chloride) , Silicates, etc., waterproofing agents (stearic acid, silicones, etc.), rust inhibitors (phosphates, nitrites, etc.), viscosity modifiers (methyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, etc.), coagulation modifiers (phosphoric acid) (Salt etc.), swelling agent (ettringite type, lime type etc.), colorant (iron oxide, chromium oxide etc.), defoaming agent (silicon type, mineral oil type etc.), reinforcing material (steel fiber, glass fiber, synthetic fiber etc.) ), Surfactants (anions, nonions, cations, etc.), thickeners, leveling agents, film forming aids,
Solvents, plasticizers, dispersants, waterproofing agents, lubricants and the like can be mentioned.

A latex or emulsion other than the latex of the present invention may be added to the resin mortar composition of the present invention. For example, vinyl acetate emulsion, ethylene-vinyl acetate emulsion, urethane emulsion,
Styrene-butadiene latex, acrylonitrile-
Examples thereof include butadiene latex. Further, a re-emulsification type powder resin may also be blended. The use of the resin mortar composition of the present invention is not particularly limited. For example, waterproofing materials for buildings, repairing materials, nursing materials, finishing materials, base conditioning materials, for tile adhesion, rust prevention, grout, putty, self-leveling floors, wear resistant floors, foundation concrete parts Examples include coating materials, deck coverings, elastic mortars, paints, anticorrosion, and molded products.

[0032]

EXAMPLES The present invention will be described based on examples. The embodiments of the present invention are not limited to these. In addition, the number of copies in the examples is the number of copies as it is (that is, the latex is the number of copies itself containing water).
showed that. Unless otherwise specified, "parts" means "parts by mass."
Is shown.

Each characteristic was obtained as follows. a. Change in viscosity of compounded product After making resin mortar compositions shown in Tables 2 and 3, 2
It was left at 0 ° C. for 4 hours and its viscosity was measured. The resin mortar composition could be prepared by weighing all the blended products and then stirring for 5 minutes. The viscosities immediately after compounding and after 4 hours were measured with a B-type viscometer, and the ratio immediately after and after 4 hours was calculated. b. Flow test After preparing resin mortar compositions shown in Tables 2 and 3, J
IS R5201 (Cement physical test method), 10.
7 The test was performed according to the method of measuring flow values. 160 mm or more was accepted.

C. State of crack occurrence 2 on the concrete flat plate specified in JIS A5304.
Apply the resin mortar composition of Table 2 and Table 3 with a thickness of mm,
After 14 days (under 20 ° C./65% RH), the state of crack initiation was observed. Further, using the test concrete plate, a hot and cold repeated test was conducted. The hot and cold repeated test is JI
S A6909 (construction finish coating material), 7.11 was tested according to the hot and cold repeated test. In the present invention, the number of times of heating and cooling was set to 20 times. The evaluation was made in five levels based on the following criteria. Three or more were passed. 5: No cracks occurred 3: Partially cracked 1: Cracked on the entire surface

D. Peeling property A concrete flat plate stipulated in JIS A5304, 2
After applying the resin mortar compositions shown in Tables 2 and 3 with a thickness of mm, the composition is left for 10 minutes. After 10 minutes, a water drop is dropped on the surface with a 2 mL dropper. Promptly stir the area where the water drops have been dropped with a finger for 30 seconds, and observe the redispersibility of the resin mortar composition in water. Three or more were passed. 5: There is no sticky feeling on the fingers after stirring. 3: The power of stirring is light, but the fingers feel a little sticky. 1: The force is required for stirring, and the fingers become sticky [Production Examples 1 to 5, Production Example 8 to 9]

A latex was obtained using the monomer composition shown in Table 1. The specific method is as follows.

To 200 parts of all the monomers having the core composition shown in Table 1, 5 parts of a 20% aqueous solution of sodium dodecylbenzenesulfonate and 50% of a 20% aqueous solution of polyoxyethylene nonylphenyl ether (HLB = 16.2) were added. Part, 8 parts of a 10% aqueous solution of ammonium peroxodisulfate and 150 parts of water were mixed, and a core part pre-emulsion was prepared using a homomixer. In addition, 20 parts of a 20% aqueous solution of sodium dodecylbenzenesulfonate and 200 parts of a 20% aqueous solution of polyoxyethylene nonylphenyl ether (HLB = 16.2) are added to 800 parts of all monomers having the shell composition shown in Table 1. Then, 32 parts of a 10% aqueous solution of ammonium peroxodisulfate and 600 parts of water were mixed, and a shell pre-emulsion was also prepared using a homomixer.

Then, 34 parts of an aqueous dispersion of seed particles (particle size 45 nm, styrene / methyl methacrylate polymer, solid content concentration 34%) and 250 parts of water were placed in a reaction vessel equipped with a stirrer and a temperature control jacket. Charge
The internal temperature was raised to 80 ° C., and 4 parts of a 10% aqueous solution of ammonium peroxodisulfate was added. To this, the core pre-emulsion was added at a constant flow rate over 1 hour. Then 0.5
The time was kept as it was, and then the shell pre-emulsion was added at a constant flow rate over 3 hours. Keep it for 1 hour after addition,
After that, cooling was performed. After cooling, the latex pH was adjusted to 8 using a 10% aqueous sodium hydroxide solution and then 100
It was passed through a wire mesh. Next, the solid content of the latex was adjusted to 40% with water. All particle size is 190 ~
It was in the range of 210 nm.

Production Example 6 7.5 parts of a 20% aqueous solution of sodium dodecylbenzenesulfonate and polyoxyethylene nonylphenyl ether (HLB = 16.2) were added to 300 parts of all monomers having the core composition shown in Table 1. Of 20% aqueous solution), 12 parts of 10% aqueous solution of ammonium peroxodisulfate and 225 parts of water were mixed, and a core pre-emulsion was prepared using a homomixer. In addition, 17.5 parts of a 20% aqueous solution of sodium dodecylbenzenesulfonate and polyoxyethylene nonylphenyl ether (HLB = 16.
175 parts of a 20% aqueous solution of 2), 28 parts of a 10% aqueous solution of ammonium peroxodisulfate, and 525 parts of water were mixed, and a shell pre-emulsion was also prepared using a homomixer.

Then, 34 parts of an aqueous dispersion of seed particles (particle size 45 nm, styrene / methyl methacrylate polymer, solid content concentration 34%), 250 parts of water were placed in a reaction vessel equipped with a stirrer and a temperature control jacket. Charge
The internal temperature was raised to 80 ° C., and 4 parts of a 10% aqueous solution of ammonium peroxodisulfate was added. To this, the core pre-emulsion was added at a constant flow rate over 1 hour and 30 minutes. afterwards,
Hold for 0.5 hours, then add 2 parts of shell pre-emulsion
It was added at a constant flow rate over a period of 30 minutes. After the addition, the mixture was kept for 1 hour and then cooled. After cooling, adjust the latex pH to 8 with a 10% aqueous sodium hydroxide solution,
After that, a 100-mesh wire mesh was passed through. Next, the solid content of the latex was adjusted to 40% with water. The particle size was 203 nm.

[Production Example 7] To 500 parts of all the monomers having the core composition shown in Table 1, 12.5 parts of a 20% aqueous solution of sodium dodecylbenzenesulfonate and polyoxyethylene nonylphenyl ether (HLB = 16.2) were prepared. ) 20% aqueous solution of 125 parts, ammonium peroxodisulfate 10%
20 parts of the aqueous solution and 375 parts of water were mixed, and a core pre-emulsion was prepared using a homomixer. Further, 12.5 parts of a 20% aqueous solution of sodium dodecylbenzenesulfonate and polyoxyethylene nonylphenyl ether (HLB = 1) were added to 500 parts of all monomers having the shell composition shown in Table 1.
125 parts of a 20% aqueous solution of 6.2), 20 parts of a 10% aqueous solution of ammonium peroxodisulfate and 350 parts of water were mixed, and a shell pre-emulsion was also prepared using a homomixer.

Then, 34 parts of an aqueous dispersion of seed particles (particle size 45 nm, styrene / methyl methacrylate polymer, solid content concentration 34%), 250 parts of water were placed in a reaction vessel equipped with a stirrer and a temperature control jacket. Charge
The internal temperature was raised to 80 ° C., and 4 parts of a 10% aqueous solution of ammonium peroxodisulfate was added. To this, the core pre-emulsion was added at a constant flow rate over 2 hours. Then 0.5
The time was maintained, and then the shell pre-emulsion was added at a constant flow rate over 2 hours. Keep it for 1 hour after addition,
After that, cooling was performed. After cooling, the latex pH was adjusted to 8 using a 10% aqueous sodium hydroxide solution and then 100
It was passed through a wire mesh. Next, the solid content of the latex was adjusted to 40% with water. The particle size was in the 205 nm range.

[Production Example 10] 1000 parts of total monomer consisting of 160 parts of styrene, 160 parts of methyl methacrylate, 600 parts of 2-ethylhexyl acrylate, 50 parts of acrylonitrile, 20 parts of 2-hydroxyethyl methacrylate and 10 parts of methacrylic acid, 25 parts of 20% aqueous solution of sodium dodecylbenzene sulfonate, 20 parts of polyoxyethylene nonylphenyl ether (HLB = 16.2)
% Aqueous solution, 40 parts of 10% ammonium peroxodisulfate aqueous solution, and 750 parts of water were mixed, and a pre-emulsion was prepared using a homomixer.

Then, 34 parts of an aqueous dispersion of seed particles (particle size 45 nm, styrene / methyl methacrylate polymer, solid content concentration 34%), and 250 parts of water were placed in a reaction vessel equipped with a stirrer and a temperature control jacket. Charge
The internal temperature was raised to 80 ° C., and 4 parts of a 10% aqueous solution of ammonium peroxodisulfate was added. The above pre-emulsion was added thereto at a constant flow rate over 4 hours. Then, it was kept for 1 hour and then cooled. After cooling, adjust the latex pH to 8 with a 10% aqueous sodium hydroxide solution,
After that, a 100-mesh wire mesh was passed through. Next, the solid content of the latex was adjusted to 40% with water. The particle size was 201 nm. The latex produced in Production Example 9 is called LTX10.

[Examples 1 to 11] Resin mortar compositions shown in Table 2 were prepared, and a. Viscosity change over time, b. Flow test, c. State of crack occurrence (normal state and repeated hot and cold conditions), d. The skin-tightness was evaluated. The evaluation results are shown in Table 2. The raw materials used are as follows. Cement: Normal Portland cement (manufactured by Taiheiyo Cement Co., Ltd.) Filler: Silica sand No. 6 (general commercial product) Methyl cellulose: hi-Metroses 90SH4000
(Made by Shin-Etsu Chemical Co., Ltd.)

Comparative Examples 1 to 4 The resin mortar compositions shown in Table 3 were prepared and a. Viscosity change over time, b. Flow test, c. State of crack occurrence (normal state and repeated hot and cold conditions), d. The skin-tightness was evaluated in the same manner as in the examples.
The evaluation results are shown in Table 3. In Comparative Example 4, 50 parts of water was further added. As can be seen from Table 3, Comparative Examples 1 and 4 were poor in repeated heating and cooling, and Comparative Examples 2 and 3 were poor in skin-tightness.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

EFFECT OF THE INVENTION By using the latex of the present invention and a composition containing cement and a filler, the viscosity of the compounded product is stable over time, cracking occurs after curing, and cracking occurs after repeated heating and cooling. It is possible to provide a composition that does not occur, has good adhesion to the underlying concrete, and has good skin-tightness.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08K 3/00 C08K 3/00 C08L 51/00 C08L 51/00 C09K 3/10 C09K 3/10 Q Z F Terms (reference) 4G012 PA04 PB26 PC08 4H017 AA04 AA27 AA28 AA36 AB17 AC04 AD06 AE03 4J002 BN031 DE137 DE147 DE267 DG057 DJ017 DJ037 DJ047 DM006 DM007 FD017 GL00 4J011 DA16 BA13 DA04 BA16 DA26 BA16 DA26 BA16 DA26 BA04 DA26 BA16 BA26 DA04 DB12 DB13 DB16 FA04 FA07 GA01

Claims (3)

[Claims] 1. A multilayer latex (1) having a core portion and a shell portion, wherein the copolymer of the core portion has a glass transition temperature of -30 ° C. or lower, and the glass transition temperature of the copolymer of the shell portion. Is −30 ° C. to 20 ° C., which is a latex for resin mortar. 2. The latex (1) comprises at least one monomer selected from aromatic vinyl monomers, methacrylic acid alkyl ester monomers and acrylic acid alkyl ester monomers, and hydroxyl group-containing vinyl. The emulsion composition is obtained by emulsion-polymerizing a monomer composition containing a base monomer, a nitrile group-containing vinyl monomer, and a carboxyl group-containing vinyl monomer. Latex for resin mortar. 3. Based on 100 parts by mass of cement (2),
A resin mortar composition containing 5 to 600 parts by mass of the filler (3) and 5 to 150 parts by mass (solid content) of the latex (1) of claim 1.