JP3041626B2 - Compounding agent for cement mortar and / or concrete - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field] The present invention relates to an ethylenically unsaturated sulfonic acid and an ethylenically unsaturated The present invention relates to a compounding agent for durable cement mortar and / or concrete, which comprises, as an essential component, a polymer latex comprising a polymer obtained by copolymerizing a specific amount of a saturated carboxylic acid or a salt thereof.

(Prior art)

BACKGROUND ART Conventionally, there has been known a method of using a polymer latex as an additive for improving durability, such as crack prevention, water resistance, abrasion resistance, chemical resistance, and neutralization prevention of cement mortar and / or concrete ( JP-A-53-8402
Four). In these conventional methods, various properties and appearance of the hydraulic inorganic composition can be improved for the time being, but these properties have not yet been sufficiently satisfied.

That is, in the cement mortar and / or concrete using the conventional polymer latex, the amount of water used during kneading, which is an important index of high durability, is large (W / C is large), and further, the water absorption of the cured product is high. The effect is insufficient in terms of suppression and neutralization, and the effect of improving the bending strength, which is a weak point of the hardened cement, is also small.

[Problems to be solved by the invention]

The present invention is different from the above-mentioned conventional additives in that the W / C is reduced, the bending strength is excellent, and the water resistance, chemical resistance,
It is an object of the present invention to provide a novel compounding agent which is excellent in suppressing carbonation and gives durable cement mortar and / or concrete.

[Means for solving the problem]

According to the present invention, there is provided a core / shell type layered polymer latex obtained by polymerizing an ethylenically unsaturated monomer containing the following components (a) and (b) as constituent monomers of a shell portion. There is provided a compounding agent for cement mortar and / or concrete characterized as being an essential component.

(A) ethylenically unsaturated sulfonic acid or a salt thereof 0.05 to 9.
95% by weight (b) Ethylenically unsaturated carboxylic acid or its salt 0.05 to 5
% By weight (however, 0.1% by weight ≦ (a) + (b) ≦ 10% by weight) That is, the compounding agent for cement referred to in the present invention is a component of the resin in the polymer latex as a raw material component of the ethylenically unsaturated component. The monomer comprising (a) an ethylenically unsaturated sulfonic acid or a salt thereof (hereinafter referred to as EMS) and (b) an ethylenically unsaturated carboxylic acid or a salt thereof (hereinafter referred to as ECA) And a polymer latex comprising a core-shell type hetero-layered polymer obtained by copolymerization.

The first characteristic of the compounding agent for cement of the present invention is as a monomer component of a polymer in a polymer latex,
(A) The use of EMS in the range of 0.05 to 9.95% by weight, preferably 0.1 to 7% by weight.

If (a) EMS with respect to all monomers is less than 0.05% by weight, the amount of water used when kneading mortar and / or concrete becomes large (W / C is large), and the compressive strength, bending strength, Performances such as abrasion resistance, shrinkage resistance, and neutralization prevention are deteriorated. If the content exceeds 9.95% by weight, the water resistance (water absorption) of the cured product is poor, which is not preferable.

The second feature of the compounding agent for cement of the present invention is that, as a monomer component of a polymer in a polymer latex,
(B) ECA is used in the range of 0.05 to 5% by weight, preferably 0.2 to 3% by weight.

If (b) ECA relative to all monomers is less than 0.05% by weight, W / C at the time of kneading mortar and / or concrete becomes large similarly to (a) EMS, and the compression limit of the cured product,
Flexural strength, abrasion resistance, shrinkage resistance, and properties such as neutralization prevention are deteriorated. If it exceeds 5% by weight, it is difficult to adjust the flow value during kneading, separation of water, etc. It is not preferable because there is a problem.

The third feature of the compounding agent for cement of the present invention is that the above-mentioned (a) EMS and (b) ECA are contained in the polymer latex in a proportion of 0.1% by weight ≦ (a).
+ (B) ≦ 10% by weight, preferably 0.5% by weight ≦ (a) +
(B) to be used in a range of ≦ 7% by weight.

When the sum of (a) EMS and (b) ECA is less than 0.1% by weight, the W / C at the time of mixing the mortar and / or concrete is large, and a large amount of polymer latex aggregates is generated.
Furthermore, the above-mentioned various properties of the cured product are reduced. Alternatively, glycidyl methacrylate, N
-When a reactive monomer such as methylol acrylamide is copolymerized, the copolymerizability is reduced, and the interpolymer crosslinking of the resulting polymer latex is inferior. Therefore, the chemical resistance of cement mortar and / or hardened concrete is reduced. Worse. If the content exceeds 10% by weight, false setting of the polymer cement mortar and / or concrete is accelerated, and the above-mentioned properties of the cured product are reduced.

As the EMS which is the component (a) according to the present invention, various EMSs can be used, and preferably, the following general formula (I) which is excellent in emulsion copolymerizability with a main component ethylenically unsaturated monomer described below, At least one of the monomers represented by (II) and (III) is used.

(Wherein, R ₁ , R ₂ , R ₃ , M ₁ , M ₂ , M ₃ and X are as follows.

R ₁ , R ₂ ; hydrogen or a methyl group, R ₁ and R ₂ may be the same or different.

R ₃ ; a linear or branched alkyl group having 1 to 4 carbon atoms even with a substituent M ₁ , M ₂ , M ₃ ; hydrogen, an alkali metal, an alkaline earth metal,
Ammonia or amine X; represents halogen or hydrogen. Representative examples of the compounds represented by the general formulas (I), (II) and (III) include the following.

Examples of General Formula (I) Styrenesulfonic acid α-methylstyrenesulfonic acid Chlorostyrenesulfonic acid and their sodium, potassium, magnesium, calcium, ammonium, monomethyldiethanolamine, triethanolamine salts Formula (II) Example) 2-acrylamide-2-methylpropanesulfonic acid 2-methacrylamide-2-methylpropanesulfonic acid 2-acrylamidobutanesulfonic acid 3-acrylamidobutane-2-sulfonic acid 3-acrylamide -2,3-dimethylbutane-2-
Sulfonic acid 2-acrylamide-2,4,4-trimethylpentanesulfonic acid 2-acrylamide microhexanesulfonic acid 2-acrylamide-2-phenylethanesulfonic acid 2-acrylamide-2-phenylpropanesulfone Acid 2-acrylamide-2-tolylethanesulfonic acid and their sodium, potassium, magnesium, calcium, ammonium, monomethyldiethanolamine, triethanolamine salts, examples of general formula (III) vinyl sulfone Acids and their sodium salts, potassium salts, magnesium salts, calcium salts, ammonium salts, monomethyldiethanolamine salts, triethanolamine salts. Among them, EMS preferably used is styrenesulfonic acid and 2-acrylamide. -2
-Methylpropanesulfonic acid and salts thereof.

The ECA as the component (b) according to the present invention includes monobasic acids such as acrylic acid, methacrylic acid, crotonic acid, and sodium, potassium, and magnesium salts thereof.
Calcium salt, ammonium salt, monomethyldiethanolamine salt, triethanolamine salt. Maleic acid, fumaric acid, dibasic acids such as itaconic acid, their acid anhydrides,
The alkali metal salts, alkaline earth metal salts, amine salts, alkyl half esters having 1 to 6 carbon atoms and half amides described above are exemplified.

Polymer latex of the compounding agent for cement of the present invention,
It can be obtained by emulsion polymerization of the aforementioned EMS and ECA with the main component ethylenically unsaturated monomer.

As the main ethylenically unsaturated monomer used in the present invention, acrylates having an ethylenic double bond (eg, ethyl acrylate, butyl acrylate, octyl acrylate), methacrylates (eg, methacrylic acid) Methyl, ethyl methacrylate, butyl methacrylate, octyl methacrylate), styrene, styrenes such as α-methylstyrene, dienes such as butadiene and isoprene, vinyls such as ethylene, vinyl acetate and vinyl propionate, acrylonitrile, α Nitriles such as methyl acrylonitrile and the like can be mentioned, but in order to obtain cement mortar and / or concrete excellent in high durability and high weather resistance, it is desirable to use (meth) acrylic esters.

In order to make the polymer latex according to the present invention into a dense reticulated three-dimensional structure (crosslinked structure), ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) ) Acrylate, polypropylene glycol di (meth) acrylate, polyoxypropylene polyoxyethylene glycol di (meth) acrylate, tri (meth) acrylate of trimethylolpropane, tetra (meth) acrylate of pentoerythritol, diallyl acrylate, divinylbenzene, In addition to crosslinkable monomers such as butadiene and triallyl isocyanurate, unsaturated monomers having a reactive functional group are used to further strengthen the crosslinked structure within and / or between the particles of the polymer latex. Preferred While used, it is unsaturated monomer having no reactive functional groups, in the emulsion polymerization system,
It is also possible to use unsaturated monomers which can be converted into compounds having active hydrogen.

Examples of the unsaturated monomer having such a reactive functional group include, for example, glycidyl acrylate glycidyl methacrylate glycidyl crotonate glycidyl allyl ether hydroxyethyl acrylate hydroxyethyl methacrylate hydroxyethyl crotonate hydroxypropyl acrylate hydroxypropyl methacrylate hydroxypropyl crotonate hydroxy Butyl acrylate Hydroxybutyl methacrylate Polyoxyethylene monoacrylate Polyoxyethylene monomethacrylate Polyoxyethylene monotonate Polyoxypropylene monoacrylate Polyoxypropylene monomethacrylate Polyoxypropylene monotonate Polyoxybutylene monoacrylate Polyoxybutylene Monocrotonate hydroxyethyl allyl ether hydroxypropyl allyl ether hydroxybutyl allyl ether polyoxyethylene allyl ether polyoxypropylene allyl ether polyoxybutylene allyl ether allylamine acrylamine methacrylamine aminostyrene α-methylaminostyrene acrylamide methacrylamide aminopropylmethacrylamide monomethyl Acrylamide Monoethylacrylamide Diethylolaminopropylacrylamide Methylallylthiol Methylmercaptostyrene N-methylolacrylamide N-methylolmethacrylamide N-methylolcrotonamide N- (2-hydroxyethyl) acrylamide N- (2-hydroxy Ethyl) methac Luminamide N- (2-hydroxypropyl) acrylamide N- (2-hydroxypropyl) acrylamide The proportion of the ethylenically unsaturated monomer having a reactive functional group is 0.1 to the total monomer. -40% by weight, preferably 0.5-10% by weight. 0.1% by weight
If it is smaller than this, the degree of crosslinking within and between the particles of the polymer latex to be formed and / or the film to be formed becomes small, and if it is more than 40% by weight, the emulsified copolymer is chipped and a large amount of agglomerates is not preferred.

As the emulsifier for emulsion polymerization of the polymer latex used in the present invention, the following anionic and nonionic emulsifiers are used.

(Representative example of anionic emulsifier)

(1) Polyoxyalkylene alkyl aryl ether sulfonate / sulfate salt (2) Polyoxyalkylene alkyl ether sulfate salt R ₄ —O— (AO) n—SO ₃ M ₄ (wherein R ₄ , A, n and M ₄ are the same as described above) (3) Polyoxyethylene alkyl aryl Ether ether sulfate salt (Wherein R ₄ , A, n and M ₄ are the same as above) M ₄ , A, n: the same as above R ₅ : hydrogen atom or methyl group R ₆ : alkyl group, alkenyl group or phenyl group having alkyl group or alkenyl group, fatty acid residue (Wherein, M ₄ , A, n, R ₅ and R ₆ are the same as above) (Wherein, M ₄ , A, n, R ₅ and R ₆ are the same as above) (Wherein, M ₄ , A, n, R ₅ and R ₆ are the same as above) (Wherein M ₄ , A, n, R ₅ and R ₆ are the same as described above) m: 0,1 R ₇ : —CH ₂ —, —CH ₂ CH ₂ — or a phenyl group (M ₄ , A, n, m, R ₅ , R ₆ and R ₇ are the same as described above) [Representative examples of nonionic emulsifiers] (10) Polyoxyalkylene alkylaryl ether (In the formula, p is 0 to 100, preferably ₅ to 70, and R ₅ and A are the same as described above.) (11) Polyoxyalkylene alkyl ether R ₄ —O— (AO) pH (wherein R ₄ , A and p is the same as described above. These anionic emulsifier and nonionic emulsifier can be used alone or in combination of two or more.
It is preferred to use one or more emulsifiers having ethylene oxide and propylene oxide groups in the molecule. More preferably, it is desirable to use the compound of the above (1) as an anionic emulsifier and one or more of the compounds of the above (10) or (11) as a nonionic emulsifier.

These emulsifiers are used in an amount of 0.5 to 15% by weight, preferably 1 to 10% by weight, based on the amount of the ethylenically unsaturated monomer. As the polymerization initiator, hydrogen peroxide alone or a combination of hydrogen peroxide and tartaric acid, citric acid, a carboxylic acid such as ascorbic acid, and hydrogen peroxide, oxalic acid, sulfinic acid and salts or oxyaldehydes thereof, Combinations with water-soluble iron salts, etc., peroxides such as persulfates, percarbonates and perborates, and 2,2′-azobis (2-aminodipropane) and its salts, 2,2′-azobis ( Water-soluble azo initiators such as N, N'-dimethylene-isobutylamidine) and its salts, and 4,4'-azobis (4-cyanovaleric acid) and its salts can be used. In preparing the polymer latex used in the present invention, it is preferable to use the above water-soluble azo-based initiator in an amount of 0.1 to 3% by weight of the unsaturated monomer mixture.

The polymer latex used in the present invention can be prepared by the following general emulsion polymerization method using the above-mentioned ethylenically unsaturated monomer, emulsifier, and polymerization initiator. Any method such as an emulsion dropping method of dropping an emulsion may be employed, but preferred methods include (a) EMS, (b) ECA, an ethylenically unsaturated monomer, a crosslinking agent, and a reactive functional group. In order to enhance the emulsion copolymerizability of the ethylenically unsaturated monomer having,
This is an emulsion polymerization method using an emulsion dropping method.

The particle structure of the polymer latex used in the present invention has a core-shell type layered structure, but the soft core and the hard shell type layered polymer latex have W / C. It is desirable because it can be reduced.

As a particularly preferred method of preparing a core-shell type layered polymer latex, an emulsifier is dissolved in an aqueous phase, a part of the core unsaturated monomer is solubilized, and then a polymerization initiator is added. Emulsification by the monomer dropping method in which the unsaturated monomer in the core part and the unsaturated monomer in the shell part are dropped in that order, or the emulsion dropping method in which the unsaturated monomer is preliminarily mixed and emulsified with a part of the emulsifier and water and the unsaturated monomer is dropped. The method can be adjusted by any method of performing polymerization, but the use of the emulsion dropping method is more preferable in order to reduce the amount of polymer adhered to the polymerization vessel or the stirring blade, which is a drawback of emulsion polymerization. In particular,
A point to keep in mind when producing a polymer latex having a core-shell type heterostratified structure is that the polymerization of the core and the polymerization of the shell form a block-type bond. The aging is preferably performed for several minutes to several hours. (A) EMS and (b) ECA are copolymerized in the shell. The polymer latex used in the present invention has a solid content
The viscosity at 40% by weight is from 10 to 1000 cp (Brookfield viscometer), and the workability is good. If the viscosity is low, the solid content can be 50% or more.

These polymer latexes used in the present invention have an average particle size of less than 2000 nm, preferably 500 nm or less,
More preferably, it is desirable to keep it at 200 nm or less. If it is more than 2000 nm, the effect of improving the strength, weather resistance, durability, water resistance, and neutralization of cement mortar and / or concrete is insufficient, and the amount of the cement mortar used is larger than that of small particles. It is not preferable.

The mixing amount of the polymer latex with the cement and / or the concrete is 0.3 to 12% by weight, preferably 0.5 to 10% by weight as solids. If it is less than 0.3% by weight, it is not preferable from the viewpoints of durability, water resistance, and prevention of neutralization. Also
If it exceeds 12% by weight, the compressive strength, which is a characteristic of a hardened cement, is undesirably reduced.

In the present invention, the durability can be further improved by using it together with a frame material such as fine particle silica (silica fume), fly ash, blast furnace slag, etc. Among them, silica fume is particularly excellent. Silica fume is effective even when added as a powder, but if kneaded with the polymer latex of the present invention in advance, there is no aggregation of the silica fume, the two materials are uniformly dispersed, and the durability of the polymer cement is significantly improved. The silica fume has a primary particle diameter of 0.1 μm or less and a partially aggregated secondary particle diameter of 1 μm.
100100 μm, and preferably SiO _{2 having} a purity of 70% or more.

Further, in the present invention, in order to further improve the durability of the cement mortar and / or concrete with a reinforcing bar, it is effective to use a rust preventive in combination. Rust inhibitors that can be used together include
There are nitrites, chromates, silicates, phosphates, organic phosphates, amines, alkylphenols, mercaptans, nitro compounds, etc., and the polymer latex of the present invention and an organic phosphate-based rust inhibitor More desirably, the combined use of 1-hydroxyalkane-1,1-diphosphonate such as 1-hydroxyethane-1,1-diphosphonate and the like has a significantly improved durability at a lower concentration than that of a commercially available sulfite. Is obtained.

Further, in carrying out the present invention, if necessary, nonionic, anionic, cationic polymer substances, coloring pigments, chelating agents, preservatives, pH adjusters, plasticizers, early strength agents,
Slow hardeners, conductive (antistatic) agents, building materials (white earth) and reinforcing agents may be used as auxiliary additives.

(Effect)

By using the compounding agent of the present invention, the obtained cement mortar and / or concrete have improved flexural strength, improved water resistance (water absorption suppression properties), and further reduced the amount of water used to suppress neutralization. And has extremely high durability, so that its practical value is extremely high.

Accordingly, the cement mortar and / or concrete additive of the present invention can be used as a base material for the inner and outer walls of a building structure, a tiling adhesive, a tiling joint, a flooring, an ACL reinforcing corrosion-resistant lining material, a water storage tank, Waterproof materials such as swimming pools, silos, bases for tennis courts, ship decks, footbridges,
Deck covering materials such as bridge decks, acid-resistant fume pipes, special concrete molded products for GRC products, semi-rigid roads such as expressways, intersections, bus terminals, tunnels, factories, steel fiber, glass fiber, carbon fiber, Spray protection coating materials for mortar and concrete skeletons using inorganic and organic fibers such as polyester fiber and polyvinyl alcohol fiber, conductive coating material using carbon fiber and metal powder (flakes), electromagnetic wave shielding material, ultra-high strength When used in the production of chemically molded products such as molded products, heavy-duty anticorrosion coating materials such as ship ballast tanks, mortar floating repair materials, cable stayed bridge wire materials, decorative bottles, and interlocking, they exhibit extremely effective performance.

[Examples] Next, in order to explain the present invention in more detail, examples are shown below.

Example 1 (1) Preparation of Polymer Latex Deionized water 209.82 was placed in a glass reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen inlet tube, and a dropping funnel.
Parts by weight, 0.945 parts by weight of sodium salt of polyoxyethylene nonyl phenyl ether (P = 8) sulfate and 2.35 parts by weight of polyoxyethylene nonyl phenyl ether (P = 30) were uniformly dissolved at room temperature and heated to 65 ° C. After warming, the atmosphere is sufficiently replaced with nitrogen. Then separately, pre-deionized water 71.8
2 parts by weight, 1.98 parts by weight of sodium salt of sulfate of polyoxyethylene nonylphenyl ether (P = 8), 4.94 parts by weight of polyoxyethylene nonylphenyl ether (P = 30), 142.74 parts by weight of butyl acrylate, 15.84 of methyl methacrylate 5% by weight of 238.07 parts by weight of an emulsion of an unsaturated monomer mixture emulsified with 3 parts by weight of trimethylolpropane trimethacrylate and 0.75 part by weight of trimethylolpropane trimethacrylate are placed in the reaction vessel and stirred for 5 minutes.

Then, 6.78 parts by weight of deionized water and 0.732 of 2,2'-azobis (N, N'-dimethyleneisobutylamidine) hydrochloride were added.
Parts by weight of the aqueous solution into the reaction vessel, and immediately, 226.17 parts by weight of the remaining unsaturated monomer mixture emulsion was continuously dropped into the reaction vessel at 65 ° C for 20 minutes to prepare the core part. did. Immediately after this, 43.97 parts by weight of deionized water and polyoxyethylene nonyl phenyl ether (=
8) 0.85 parts by weight of sodium salt of sulfate ester of 8), 2.11 parts by weight of polyoxyethylene nonylphenyl ether (= 30), 20.28 parts by weight of butyl acrylate, 47.27 parts by weight of methyl methacrylate, 0.15 part by weight of trimethylolpropane trimethacrylate
119.38 parts by weight of an unsaturated monomer mixture emulsion consisting of 2.5 parts by weight of an ethylenically unsaturated sulfonate (EMS) shown in Table 1, and 2.25 parts by weight of an ethylenically unsaturated carboxylic acid (ECA) shown in Table 1 for 10 minutes. And dripping continuously
Polymerizes at 65 ° C.

After dropping the emulsion of the unsaturated monomer mixture,
Aged at 60 ° C for 60 minutes, cooled to 30 ° C, and then
The core-shell type polymer latex was obtained by adjusting with deionized water and triethanolamine, respectively, so that the weight% and the pH became 7.

(2) Performance Evaluation The polymer latex prepared as described above was evaluated, and the polymer latex was evaluated as an admixture for polymer cement.

Evaluation of polymer latex The average particle size and crosslinkability were measured by the following methods.

Average particle size: Coulter submicron particle analyzer (Coulte Electronics Co., USA, Coulte
r Model N4 type).

Crosslinkability: 30 g of a polymer latex adjusted to have a solid content of 40% by weight was uniformly cast on a glass plate of 12 cm × 14 cm, and air-dried at 25 ° C. The film thus obtained was cut into 2 cm × 4 cm, immersed in a petri dish filled with benzene at 20 ° C. for 48 hours, and evaluated based on the degree of swelling and solubility of the film as follows.

；: Equal to or slightly swelling with the film area (2 cm × 4 cm) before immersion in benzene.

Δ: The degree of swelling is large and the film shape is impaired.

X: The film was dissolved in benzene and turned into a uniform liquid.

Evaluation of admixtures for polymer cement i) Adjustment of polymer cement Normal Portland cement 1kg Mountain sand (Kisarazu) 2kg Antifoaming agent (non-ionic) 1g Polymer latex 150g (solid content 60g) and flow value (JISR5201) 200 Necessary water was added so as to be ± 10, and the mixture was kneaded with a paddle mixer and subjected to measurement of kneading properties. Further, the kneaded material was placed in a mold (4.0 × 4.0 × 16.0 cm), cured, released from the mold, and subjected to evaluation of the performance of a cured product.

ii) Polymer cement evaluation The kneading properties and the performance of the cured product were evaluated according to the following methods.

Kneading properties • Unit volume weight; JISA1116 • W / C; Water volume / cement weight × 100 Cured body performance • Flexural strength test; JIS R-5201 • Compressive strength test; JIS R 5201 • Adhesive strength test; JIS A 6915 • Water absorption Test: JIS A 1404 ・ Abrasion test; JIS A 1451 ・ Dry shrinkage test; JIS A 1129 ・ Neutralization test: Curing a 4 × 4 × 16 cm rectangular specimen at 20 ° C. and 80% RH for 1 week The sample was left for 3 months in a pressurized autoclave with a CO ₂ concentration of 5% and 1 kg / cm ² , the specimen was taken out, cut in the middle of the specimen, and a 1% phenolphthalein alcohol solution was sprayed on the cut surface. Then, the area of the portion where the red color disappeared was measured, and the neutralization rate was calculated as a ratio to the total cross-sectional area.

Table 1 shows the kneading properties and curability measured by the above methods.
Shown in Material Nos. 1 to 7 are examples of the present invention, and material No. 8
To 11 are comparative examples.

Example 2 In accordance with Example 1, a polymer of a polymer latex which produces 2-acrylamide-2-methylpropanesulfonic acid (AMPS) as an ethylenically unsaturated sulfonate and methacrylic acid (MA) as an ethylenic carboxylic acid A polymer latex was prepared by using as a monomer constituent component of the formula (1) in an amount of weight% in Table-2.

Next, the polymer latex prepared as described above was evaluated as an admixture for polymer cement.

 Table 2 shows the results.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI // C04B 111: 60 (56) Reference JP-A-60-42264 (JP, A) JP-A-63-291910 (JP, A) JP 53-84024 (JP, A) JP-A-3-205333 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 24/26

Claims (3)

(57) [Claims] 1. A core / shell type layered polymer latex obtained by polymerizing an ethylenically unsaturated monomer containing the following components (a) and (b) as constituent monomers of a shell portion is essential. A compounding agent for cement mortar and / or concrete, characterized as being a component. (A) ethylenically unsaturated sulfonic acid or its salt 0.05 to
9.95% by weight (b) Ethylenically unsaturated carboxylic acid or its salt 0.05 to
5% by weight (However, 0.1% by weight ≦ (a) + (b) ≦ 10% by weight) (2) The ethylenically unsaturated sulfonic acid or a salt thereof as the component (a) is at least one selected from styrenesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid and salts thereof. The compounding agent for cement mortar and / or concrete according to claim 1, wherein: 3. An average particle diameter of the polymer latex is 500 nm.
Claims (1) having a crosslinked structure below.
Or the compounding agent for cement mortar and / or concrete according to (2).