JP2006001789A - Cement admixture and cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cement composition which has mechanical strength equivalent to those of conventional cement compositions and an extremely low TVOC, by improving components in a cement admixture. <P>SOLUTION: The cement admixture having a TVOC of <1,000 μg/m<SP>3</SP>is obtained by compounding (B) 0.5-10 pts.wt. nonionic surfactant with (A) 100 pts.wt., calculated in terms of solid content, of aliphatic conjugated diene-(meth)acrylate copolymer latex and/or alkyl (meth)acrylate (co)polymer latex with a glass transition temperature of from -40 to +40°C. The cement composition is obtained by compounding the cement admixture with cement. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cement admixture and a cement composition using the same, and more particularly to a cement admixture having a low total volatile organic substance (TVOC) content and a cement composition using the same.

Conventionally, as latex for cement admixtures blended in cement compositions, natural latex, styrene-butadiene latex, acrylonitrile-butadiene latex, styrene- (meth) acrylate latex, ethylene-vinyl acetate latex, chloroprene There is a system latex (Patent Document 1), and it has been put into practical use to improve the fluidity and mechanical strength of the cement composition by mixing them with cement. However, in recent years, it has become clear that endocrine disrupting substances such as styrene remain in the cement composition, and that symptoms such as sick house syndrome caused by total volatile organic substances (TVOC) are induced, and countermeasures are required. ing.
JP-A-4-295037

  The problem to be solved by the present invention is to obtain a cement admixture having a low TVOC and to provide a cement composition having a low residual volatile organic substance content having the same functional strength as that of the conventional cement admixture. To do.

The present invention provides (A) an aliphatic conjugated diene- (meth) acrylate copolymer latex and / or a (meth) acrylate (co) polymer latex (hereinafter referred to as “glass transition temperature” of −40 to + 40 ° C.). The present invention relates to a cement admixture characterized by blending 0.5 to 10 parts by weight of (B) a nonionic surfactant with respect to 100 parts by weight of “(co) polymer latex”) in terms of solid content. .
Here, it is preferable not to use styrene as the monomer constituting the component (A).
Moreover, as (B) nonionic surfactant, what is a polyoxyethylene alkyl ether type | mold and HLB (hydrophile lyophile balance) is 12-17 is preferable.
In addition, when the (B) nonionic surfactant is a polyoxyethylene alkylphenol ether type, the alkyl group has 1 to 3 or 10 or more carbon atoms and HLB (hydrophile lyophile balance) is 12 to 17 Some are preferred.
Further, the TVOC (total volatile organic substance: a value measured by the JIS A1901 method (small chamber method)) of the cement admixture is preferably less than 1,000 μg / m ³ .
Next, this invention relates to the cement composition characterized by mix | blending 0.5-100 weight part of cement admixtures of this invention in conversion of solid content with respect to 100 weight part of cement.

The cement admixture of the present invention comprises (A) an aliphatic conjugated diene- (meth) acrylic acid ester copolymer latex and / or a (meth) acrylic acid alkyl ester (co) polymer latex and (B) a nonionic surfactant. Since it is used in combination, it is environmentally friendly as a cement admixture and has excellent stability when mixed with cement.
In addition, when a nonionic surfactant (B) having a polyoxyethylene alkyl ether type and an HLB of 12 to 17 is used, the cement mixing stability is improved in a small amount.
Further, (B) as a nonionic surfactant, a polyoxyethylene alkylphenol ether type, wherein the alkyl group has 1 to 3 or 10 or more carbon atoms and HLB (hydrophile lyophile balance) is 12 to 17 When used, no endocrine disrupting substance is generated, and the balance between cement miscibility, physical properties of cement mortar such as bending strength and adhesive strength is excellent.
Furthermore, if the TVOC of the cement admixture is less than 1,000 μg / m ³ , the cement composition using this does not cause sick house syndrome and is excellent in health.

Cement admixture;
The cement admixture of the present invention comprises (A) an aliphatic conjugated diene- (meth) acrylic acid alkyl ester copolymer latex and / or (meth) acrylic acid alkyl ester (copolymer) having a glass transition temperature of −40 to + 40 ° C. ) A polymer latex and (B) a nonionic surfactant are the main components.

Examples of the aliphatic conjugated diene constituting the (A) (co) polymer latex include 1,3-butadiene, isoprene, 2-chloro-1,3-butadiene, 2-methyl-1,3-butadiene and the like. 1,3-butadiene is preferred.
The (A) copolymer latex constituting the copolymer latex is an ethylenically unsaturated carboxylic acid alkyl ester having an alkyl group having 1 to 12 carbon atoms, such as methyl (meth) acrylate. , Ethyl (meth) acrylate, i-propyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, n (meth) acrylate -Amyl, i-amyl (meth) acrylate, hexyl (meth) acrylate, 2-methylhexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, i-nonyl (meth) acrylate, (meth) Decyl acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, etc., preferably methyl (meth) acrylate, (meth ) Acrylate, (meth) acrylate n- butyl (meth) acrylate, 2-methylhexyl, and the like (meth) acrylic acid 2-ethylhexyl. These (meth) acrylic acid alkyl esters can be used alone or in combination of two or more.
Preferable specific examples of the (A) (co) polymer latex are butadiene / methyl methacrylate copolymer latex and n-butyl acrylate / methyl methacrylate copolymer latex.

(A) The proportion of the aliphatic conjugated diene and the (meth) acrylic acid alkyl ester constituting the copolymer latex is 0 to 50% by weight, preferably 20 to 45% by weight, (meth) acrylic. The acid alkyl ester is 100 to 50% by weight, preferably 80 to 55% by weight (however, the total is 100% by weight).
When the (meth) acrylic acid alkyl ester is 100% by weight, the component (A) is a (meth) acrylic acid alkyl ester (co) polymer latex.

In the (A) (co) polymer latex used in the present invention, other monomers other than the above can be used in combination.
Other monomers include α-methyl styrene, p-methyl styrene, vinyl toluene, chlorostyrene, sodium styrene sulfonate and other aromatic vinyl compounds, acrylonitrile, methacrylonitrile and other cyanidated vinyl compounds, vinyl acetate, etc. Carboxylic acid vinyl ester, vinyl pyridine, hydroxyalkyl ester of ethylenically unsaturated carboxylic acid containing amino group such as methacrylamide propyl trimethyl ammonium chloride, N-butoxymethyl (meth) acrylamide, N-butoxyethyl (meth) acrylamide, Nn-propoxymethyl (meth) acrylamide, acrylamide, methacrylamide, methyl methacrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acryl Amide, ethylenically unsaturated carboxylic acid amides such as N-ethyl (meth) acrylamide, glycidyl monomers such as glycidyl (meth) acrylate, halogen-containing vinyl monomers such as vinyl chloride and vinylidene chloride, and itacon Examples thereof include ethylenically unsaturated carboxylic acids such as acid, acrylic acid, methacrylic acid and fumaric acid.
The above-mentioned other monomers are 7% by weight or less, preferably 3% by weight or less in the total monomer components constituting the (A) (co) polymer latex.

  In addition, when an aliphatic conjugated diene is used as the (A) (co) polymer latex, the resulting cement composition has particularly excellent mechanical strength and adhesiveness, and the carbon number of the alkyl group. When the (meth) acrylic acid alkyl ester having 4 to 12 is used, the resulting composition is particularly excellent in weather resistance.

The (A) (co) polymer latex is obtained by emulsion polymerization of the monomer component in an aqueous medium.
That is, the (A) (co) polymer latex is obtained by carrying out emulsion polymerization by adding a monomer, a polymerization initiator, an emulsifier, a chain transfer agent and the like to an aqueous medium (usually water).
The polymerization initiator is not particularly limited. For example, hydroperoxides such as cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide, peroxides such as benzoyl peroxide and lauroyl peroxide, azobisiso Inorganic polymerization initiators such as organic polymerization initiators such as azo compounds such as butyronitrile and persulfates such as potassium persulfate, sodium persulfate, and ammonium persulfate can be used. The usage-amount of a polymerization initiator is 0.03 to 2 weight% normally with respect to a monomer part, Preferably it is 0.05 to 1 weight%.
In order to promote emulsion polymerization, for example, reducing agents such as sodium pyrobisulfite, sodium sulfite, sodium hydrogensulfite, ferrous sulfate, glucose, L-alcorbic acid and salts thereof, glycine, alanine, sodium ethylenediaminetetraacetate A chelating agent such as can also be used in combination.

The emulsifier is not particularly limited, and any of anionic, nonionic, and amphoteric surfactants can be used. These can be used alone or in admixture of two or more.
The amount of the emulsifier used is 0.5 to 10% by weight, preferably 1 to 8% by weight, based on the monomer. On the other hand, when it exceeds 10% by weight, the adhesiveness, bending strength and water permeability of the cement composition as the final product are lowered, which is not preferred.

  There are no particular restrictions on the chain transfer agent, and α-methylstyrene dimer, preferably α-methylstyrene dimer containing 60% by weight or more of 2-4-diphenyl-4-methyl 1-pentene component, terbinolene, α-terpinene, γ- Terpinene, dipentene, octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-hexadecyl mercaptan, diethyl xanthogen disulfide, dimethyl xanthogen disulfide, diisopropyl xanthogen disulfide, tetramethyl thiuram monosulfide, tetraethyl thiuram disulfide, tetrabutyl thiuram disulfide, Dipentamethylene thiuram disulfide can be used, and these can be used alone or in combination of two or more. These chain transfer agents are usually used in an amount of 0 to 15% by weight based on the monomer.

  There is no restriction | limiting in particular also about an emulsion polymerization method and its conditions, It can implement under a conventionally well-known method and conditions. For example, in the emulsion polymerization, in addition to the polymerization initiator, the emulsifier, the chain transfer agent, if necessary, a chelating agent, a pH adjuster, an electrolyte, etc. are used in combination, Emulsion polymerization is carried out under polymerization conditions of a polymerization time of 1 to 40 hours using 100 to 300 parts by weight of water and the polymerization initiator, emulsifier, chain transfer agent and the like in amounts within the above ranges. As a method for adding the monomer, any of a batch addition method, a divided addition method, a continuous addition method, a method of emulsifying and adding the monomer in advance, or a combination thereof may be used. Among these methods, the divided addition method, the continuous addition method, or the continuous addition method of the emulsified monomer is preferable from the viewpoint of reducing the formation of coagulum and removing reaction heat.

The final polymerization conversion rate of the (co) polymer latex is preferably 90 to 100%, particularly 95 to 100%. The toluene-insoluble content of the (co) polymer latex thus emulsion-polymerized is preferably 50 to 99% by weight, more preferably 55 to 95% by weight.
Here, the toluene insoluble matter is a film having a thickness of 0.3 mm obtained by drying a (co) polymer latex adjusted to pH 7 or higher to a moisture content of 0.2% by weight or less on a glass plate. 3 g was placed in 100 ml of toluene and allowed to stand at room temperature for 24 hours, and then filtered through a 120 mesh wire mesh. The residue remaining on the wire mesh was dried and weighed, and the weight% was obtained by dividing the latex total solids.
If the toluene-insoluble content is less than 50% by weight, the adhesiveness, bending strength, water resistance, and effectiveness of the cement composition to the base material are inferior. On the other hand, if it exceeds 99% by weight, the adhesiveness to the base material is inferior. It is not preferable because the cement mixing stability is deteriorated and the usable time is shortened.
The toluene insoluble matter can be easily adjusted by selecting the type and amount of chain transfer agent that is a molecular weight regulator. For example, when methyl bromide, which is a halogen compound, or α-mail styrene dimer is used as a chain transfer agent, the amount used is 0 to 8% by weight. Examples of mercaptans include t-dodecyl mercaptan, n- When dodecyl mercaptan is used, the amount used is 0 to 2% by weight. In addition, as a method for adjusting the toluene insoluble matter, there are selection of the amount of polymerization initiator at the time of polymerization, the polymerization start temperature, and the like, and these can be combined to obtain the desired copolymer latex.

  The average particle diameter of the (A) (co) polymer latex (aqueous dispersion) obtained is preferably 50 to 450 nm, more preferably 70 to 350 nm. Here, the average particle diameter is a value calculated from a number average by treating latex with osmic acid, taking this in an electron micrograph at a magnification of 30,000, measuring the particle diameter of 100 or more particles, and the like. Furthermore, although a solid content of less than 10% by weight can be produced, considering the next water removal step, the solid content is preferably 10% by weight or more.

The glass transition temperature (Tg) of the polymer constituting the (A) (co) polymer latex of the present invention is −40 to + 40 ° C., preferably −20 ° C. to + 20 ° C., more preferably −10 ° C. to + 15 ° C. When the glass transition temperature is less than −40 ° C. and exceeds + 40 ° C., the bending strength, compressive strength and adhesive strength of the resulting cement composition are weakened.
The glass transition temperature of the (A) (co) polymer latex can be adjusted by, for example, the ratio between 1,3-butadiene and methyl methacrylate, the type and amount of the molecular weight modifier.

The glass transition temperature in the present invention is a value measured under the following conditions using a differential scanning calorimeter (DSC) manufactured by Rigaku Corporation.
(1) About 5 g of the product is thinly drawn on a glass plate and dried at 25 ° C. for 24 hours to obtain a polymer film.
(2) The glass transition temperature of the obtained dry film is measured under the following conditions.
Condition: Temperature rising rate: 20 ° C / min Atmosphere: Nitrogen gas Sample amount: 20mg

Next, the (B) nonionic surfactant used in the cement admixture of the present invention is preferably a polyoxyethylene alkyl ether type represented by the following general formula (1) or a general formula (2) And polyoxyethylene alkylphenol ether type represented by
R—O— (CH ₂ CH ₂ O) n —OH General formula (1)
_{R-A-O- (CH 2} CH 2 O) n-OH Formula (2)
(In the general formula (2), R represents an alkyl group having 1 to 3 or 10 or more carbon atoms, and A is a benzene ring. Here, R is a polyoxyethylene alkylphenol ether type having 4 to 9 carbon atoms. Surfactants are endocrine disruptors and are not preferred.)

(B) HLB of nonionic surfactant is 12-17, Preferably it is a combined system of HLB 11-11 and HLB 15-17. Specifically, it is a combination of Emulgen 1108 made by Kao with an HLB of 13.5 and Emulgen 1118S with an HLB of 16.7. When HLB is less than 12 and exceeds 17, stability when cement and cement admixture are mixed is poor. Here, HLB is an index representing the ratio of hydrophilicity to hydrophobicity in the analysis of the surfactant, and the larger the numerical value, the higher the hydrophilicity.
The amount of the (B) nonionic surfactant used is 0.5 to 10 parts by weight, preferably 1.0 to 7.0, based on 100 parts by weight of the (A) (co) polymer latex (in terms of solid content). Part by weight, more preferably 1.5 to 6.0 parts by weight. If the amount is less than 0.5 part by weight, the stability when the cement and the cement admixture are mixed is poor. On the other hand, if the amount exceeds 10 parts by weight, the adhesive strength of the resulting cement composition becomes weak.

  In the cement admixture of the present invention, (A) (co) polymer latex is added with (B) a nonionic surfactant or, if necessary, a silicon-based antifoaming agent such as dimethylpolysiloxane, methylcellulose, Water retention agents such as hydroxyethyl cellulose, casein and PVA, cement hardening accelerators such as potassium carbonate, lithium carbonate and calcium chloride, cement hardening retarders such as citric acid, tartaric acid and lignin, water reduction such as naphthalene sulfonic acid and lignin sulfonic acid Agents, pigments, preservatives and the like can be added.

The cement admixture of the present invention preferably has a TVOC of less than 1,000 μg / m ^{3 in} all components. When the TVOC is 1,000 μg / m ³ or more, it is not good for health. In particular, if TVOC exceeds 3,000 μg / m ³ , sick house syndrome is caused, which is not good for health problems. Here, the value of TVOC is a value measured by JIS A1901 method (small chamber method).
In addition, as a method of lowering TVOC, after polymerization of the copolymer latex used for the cement admixture is completed, steam is added and distilled under reduced pressure, or peroxidation of cumene hydroperoxide, tertiary hydroperoxide, etc. There is a method of reducing residual monomer by a method of adding a product.

  The above TVOC is a general term for Total Volatile Organic Compounds (total volatile organic compounds). It is a value measured by the “small chamber method”. The numerical value is a numerical value obtained by analyzing with a gas chromatograph and converting to toluene using the total peak total area of VOCs detected in the range from n-hexane to n-hexadecane.

Volatile organic substances (VOC) that are subject to regulation in 2002 by the Ministry of Health, Labor and Welfare include formaldehyde [100 μg / m ³ (0.08 ppm)], toluene [260 μg / m ³ (0.07 ppm)], Xylene [870 μg / m ³ (0.20 ppm)], p-dichlorobenzene [240 μg / m ³ (0.04 ppm)], ethylbenzene [3,800 μg / m ³ (0.88 ppm)], styrene [220 μg / m ³ (0.05 ppm)], di-n-butyl phthalate [220 μg / m ³ (0.02 ppm)], tetradecane [330 μg / m ³ (0.04 ppm)], di-2-ethylhexyl phthalate [120 μg / m ³ (7.6 ppb)], acetaldehyde [48 μg / m ³ (0.03 ppm)] chlorpyrifos (1 μg / m ³ ( 0.07ppb), and the like diazinon ^{(0.29μg / m 3 (0.02ppb)} .

Cement composition;
The cement admixture of the present invention is prepared as a cement composition by being mixed with cement, and is applied as various civil engineering structures.
The amount of the cement admixture used in the cement composition is 0.5 to 100 parts by weight, preferably 1.0 to 80 parts by weight, and more preferably 1.5 to 40 parts by weight in terms of solid content with respect to 100 parts by weight of cement. Parts by weight. If the amount of the cement admixture used is less than 0.5 parts by weight, the adhesion and bending strength of the resulting cement composition are inferior. On the other hand, if it exceeds 100 parts by weight, not only will the cost be increased, but there will be a cement composition that meets the cost. I can't get it.
In addition, as cement used for the cement composition of the present invention, various Portland cements such as ordinary Portland cement, super early strength Portland cement, moderately hot Portland cement, sulfate resistant Portland cement, white iron Portland cement, blast furnace cement, Known cements such as silica cement, fly ash cement, alumina cement, solidit, calcium silicate; or a mixed cement obtained by combining two or more of these; a cement obtained by mixing these cements with an inorganic substance such as gypsum it can.

When the cement composition is used as mortar or concrete, the aggregate / cement ratio in which sand or gravel is added to the cement can be variously changed depending on the purpose of use. More than 150 kg of cement is used per ^three .
The cement composition of the present invention can be prepared by mixing cement, a cement admixture, and sand and gravel to be added as necessary by a known mixing method using a mill or a blender.
The amount of water relative to the cement composition of the present invention is not particularly limited and is determined from the physical properties of the composition after curing, but is usually 20 to 80 weights per 100 parts by weight of the cement composition. Parts, preferably 25-60 parts by weight. However, the amount of water here includes water contained in the cement admixture. Regardless of the amount of water, the cement admixture used in the present invention can highly disperse cement into water. Moreover, a high-strength cement secondary product can also be manufactured by steam curing, autoclave curing, and centrifugal molding.

The cement composition is characterized in that the specific cement admixture of the present invention is added, and the addition of the cement admixture provides extremely high fluidity with the same blending amount. When the workability is remarkably improved while the fluidity is the same, the addition of the cement admixture according to the present invention can reduce the water / cement ratio, so that a high-strength and less cracked cement composition is obtained. It is done.
Moreover, since TVOC is low, it is preferable in terms of health and environment.
Therefore, the cement composition of the present invention can be used for many applications that require high workability and high quality. In concrete, artificial concrete, expanded concrete, hydrated concrete, shielding concrete, hot concrete, cold concrete , Prestressed concrete, precast concrete, pavement concrete, dam concrete, concrete subjected to seawater action, concrete using sea sand, concrete using sliding foam method, concrete with exposed finish, fluidized concrete, asphalt concrete, etc. . Especially suitable for asphalt concrete and mortar.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, unless otherwise indicated, the part and% in an Example are a weight part and weight%.

(1) Production of copolymer latex Using a stainless steel autoclave with an internal volume of 100 liters, in a nitrogen gas atmosphere, the monomers shown in Table 1, 0.3 parts of potassium persulfate as a polymerization initiator, and t as a molecular weight regulator. -0.3 parts of dodecyl mercaptan, 1.8 parts of sodium diphenyl ether disulfonate and 145 parts of water as emulsifiers, emulsion polymerization with stirring at a polymerization temperature of 60 ° C to 80 ° C, and copolymer latex shown in Table 1 (AF) Six types were manufactured.
The polymerization conversion rate at this time was 99% or more.
The obtained latex was adjusted to pH 7.5 to 9.0 using sodium hydroxide and adjusted to a solid content of 50%. In addition, about copolymer latex A-C, after adjusting pH with sodium hydroxide, steam was thrown in, liquid temperature was set to 60 degreeC, TVOC was reduced, and also it concentrated under pressure reduction and adjusted to 50% of solid content.

(2) Preparation of cement admixture Examples 1 to 3 and Table shown in Table 2 by adding 0.2 parts of a silicone-based antifoaming agent and a nonionic surfactant to the six types of copolymer latex produced above. The cement admixtures of Comparative Examples 1 to 8 shown in 3 were obtained.

(3) Preparation of cement mortar composition The cement mortar composition using the cement admixtures of Examples 1 to 3 and Comparative Examples 1 to 8 was a universal stirrer with 100 parts of Portland cement, 150 parts of silica sand 6, 150 parts of silica sand. No. 150 parts was kneaded in advance, and 5 parts of cement admixture, 0, 2 parts of silicone-based antifoaming agent and water were added in an appropriate amount, and stirring was adjusted so that the flow value was 170 mm ± 10. Thereafter, cement mortar was poured into a 4 cm × 16 cm × 4 cm mold to create a sample exclusively for bending strength and compressive strength.

Measurement of TVOC According to JIS A1901, “Measurement method for emission of volatile organic compounds (VOC), formaldehyde and other carbonyl compounds in building materials—small chamber method”.
The sample was prepared by applying 1.2 g (as a dry film) of a cement admixture to an 80 cm ² SUS plate and measuring it according to the method according to JIS A-1901.
The measured value of TVOC was set as the measured value on the third day after VOC was diffused from the sample after setting the sample in the chamber. The measurement results are shown in Tables 2 and 3.

(4) Measurement of bending strength and compressive strength It measured according to the test method of the cement mortar of JIS A6203 shown below.
(I) Curing time: 4 weeks (20 ° C. × 60% × under RH × 2 days) + (5 days in water) + 20 ° C. × 60% RH under 21 days)
(Ii) Measurement: An average value of 3 bending strengths and 6 compressive strengths was taken as bending strength and compressive strength.
Testing machine: Shimadzu autograph Bending strength = 1 mm / min Compressive strength = 1.5 mm / min

(5) Preparation and measuring method of test body for measuring adhesive strength Measured according to the test method for cement-based foundation conditioner of JIS A6916.
Cement mortar is prepared by the blending method of cement mortar shown in Table 3 below, and 4cm x 4cm x 0.4cm (length x width x thickness) cement mortar is handed over to the groundwork (concrete sidewalk board) for 14 days curing. After carrying out, the adhesive strength between the concrete sidewalk board and cement mortar was measured. The measurement results are shown in Tables 2 and 3.

Nonionic surfactant (manufactured by Kao Corporation)
Emulgen 404; polyoxyethylene oleyl ether (HLB = 8.8, carbon number of alkyl group = 18)
Emulgen 1108; polyoxyethylene alkyl ether (HLB = 13.5, carbon number of alkyl group = 9)
Emulgen 1118; polyoxyethylene alkyl ether (HLB = 16.7, carbon number of alkyl group = 9)
Emulgen 1150S; polyoxyethylene alkyl ether (HLB = 18.5, carbon number of alkyl group = 9)
Emulgen 910; polyoxyethylene nonylphenol ether (HLB = 12.3, carbon number of alkyl group = 9)

As is clear from Table 1, Examples 1 to 3 using copolymer latexes A to C within the scope of the present invention have a low TVOC value and are excellent in overall mortar performance.
On the other hand, in Comparative Examples 1 to 5, the nonionic surfactant added as a cement admixture is outside the scope of the present invention, and the cement mortar performance is inferior. In Comparative Examples 6 to 8, the copolymer latex is outside the scope of the present invention, the TVOC value is high, and the cement mortar performance is inferior.

The cement admixture of the present invention has the same level of functional strength as the conventional one and at the same time has a low TVOC. Therefore, the cement composition using the cement admixture does not cause air pollution or sick house, and is used in various fields such as building materials. Is possible.

Claims (6)

  (A) Aliphatic conjugated diene- (meth) acrylic acid ester copolymer latex and / or (meth) acrylic acid alkyl ester (co) polymer latex having a glass transition temperature of −40 to + 40 ° C. in terms of solid content A cement admixture comprising 0.5 to 10 parts by weight of (B) a nonionic surfactant with respect to 100 parts by weight.   The cement admixture according to claim 1, wherein styrene is not used as a monomer constituting the component (A).   The cement admixture according to claim 1 or 2, wherein the (B) nonionic surfactant is a polyoxyethylene alkyl ether type and an HLB (hydrophile lyophile balance) is 12 to 17.   (B) The nonionic surfactant is a polyoxyethylene alkylphenol ether type, the alkyl group has 1 to 3 or 10 or more carbon atoms, and HLB (hydrophile philophile balance) is 12 to 17. 2. The cement admixture according to 2. The cement admixture according to any one of claims 1 to 4, wherein the cement admixture has a TVOC (total volatile organic substance: a value measured by JIS A1901 method (small chamber method)) of less than 1,000 µg / m ³ . A cement composition comprising 0.5 to 100 parts by weight of the cement admixture according to any one of claims 1 to 5 in terms of solid content per 100 parts by weight of cement.