JP2010006682A - Additive for cement, and cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an additive for cement which has reduced influence on the air content of mortar and concrete and has excellent dry shrinkage reduction effect for mortar and concrete. <P>SOLUTION: The additive for cement comprises: an oxyalkylene compound (a) composed of a specified compound (a1) and a specified compound (a2) according to necessity; and a 14 to 30C anionic surfactant (b) which does not have an oxyalkylene group, in which the (a) is dissolved into water in an optional ratio or uniformly dispersed at ordinary temperature, and also, the cloud point of the 5% aqueous solution of the (a) is ≤40°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cement additive and a cement composition using the same.

A dry shrinkage reducing agent has been used for a long time in order to suppress dry cracking, which is one of the major drawbacks of mortar and concrete, and examples of the dry shrinkage reducing agent include, for example, alkylene (alcohol having 1 to 4 carbon atoms). Oxide adducts and alkylene oxide adducts of alkyl (having 1 to 4 carbon atoms) phenol are known (Patent Documents 1 and 2).
However, mortar and concrete to which conventional drying shrinkage reducing agents for cement are added are difficult to adjust to the desired amount of air because the amount of air is kneaded and greatly affected by temperature. The drying shrinkage reducing agent may greatly affect the air volume of the mortar or concrete just by mixing it in a very small amount in the mortar or concrete. Therefore, careful and great labor is required to clean the equipment (mixer car and agitator car). There was a problem of being.

JP 56-37259 A Japanese Examined Patent Publication No. 62-10947

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an additive for cement that has a small effect on the amount of air in mortar and concrete and is excellent in the effect of reducing drying shrinkage of mortar and concrete. is there.

The inventors of the present invention have arrived at the present invention as a result of intensive studies to solve the above problems. That is, the present invention relates to an oxyalkylene compound (a) comprising the compound (a1) represented by the general formula (1) and, if necessary, the compound (a2) represented by the general formula (2), and a carbon having no oxyalkylene group. A cement additive comprising an anionic surfactant (b) of several 14 to 30, wherein (a) is dissolved or uniformly dispersed in water at an arbitrary ratio at room temperature, and (a) And a cement composition comprising a cement additive having a cloud point of 40 ° C. or lower and a cement additive, cement, water and aggregate.
R ¹ O (A ¹ O) nH (1)
[Wherein, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, A ¹ O is an oxyalkylene group having 2 to 4 carbon atoms, n is an average value of 1 to 20 and n is 2 or more. In this case, n A ¹ Os may be the same or different. ]
R ² O (A ² O) mH (2)
[In the formula, R ² is a hydrogen atom or a residue obtained by removing a hydroxyl group from a C 1-8 tetravalent saturated aliphatic alcohol, A ² O is a C 2-4 oxyalkylene group, (A ² O) 50 to 100 mol% in m is an oxypropylene group and / or oxybutylene group, and m is a number up to 100 which is an average value exceeding 10 and a number which is 1 or more larger than n in the general formula (1). And the m pieces of A ² O may be the same or different. ]

  The cement additive of the present invention is extremely less affected by the temperature and amount of addition and decrease in the amount of air in mortar and concrete. Therefore, the cement additive of the present invention makes air management much easier than when a conventional cement drying shrinkage reducing agent is added, and also carefully cleans equipment such as mixer trucks and agitator cars. And there is no need to spend a lot of effort.

  In the present invention, the oxyalkylene compound (a) exhibiting the effect of reducing drying shrinkage is characterized in that the clouding point of its 5% aqueous solution is 40 ° C. or lower. The foaming properties of oxyalkylene compounds vary greatly depending on the temperature and concentration. However, by setting the cloud point to 40 ° C. or less, the foaming properties are almost eliminated, and even when added to mortar or concrete, air is almost entrained. As a result, the air quantity can be easily managed. The cloud point of the oxyalkylene compound (a) is preferably 30 ° C. or lower, more preferably 20 ° C. or lower, and most preferably 10 ° C. or lower.

  Further, in order for the oxyalkylene compound (a) to exhibit the effect of reducing drying shrinkage, it is necessary to dissolve or uniformly disperse in an arbitrary proportion of water at normal temperature (a normal temperature not heated or cooled). In the case of uniform dispersion, it is necessary to stably disperse for at least 24 hours.

  The cloud point of the oxyalkylene compound (a) can be lowered by increasing the hydrophobicity of the compound, and in order to stabilize the amount of air, it is better to have a certain degree of hydrophobicity, but the hydrophobicity becomes too high. It will not dissolve or uniformly disperse in water, and it will not be possible to exhibit a predetermined drying shrinkage reduction effect. Therefore, it is necessary to adjust the hydrophobicity of (a) so that the cloud point is 40 ° C. or lower and is dissolved or uniformly dispersed in an arbitrary proportion of water.

  The oxyalkylene compound (a) includes a compound (a1) represented by the general formula (1) and, if necessary, a compound (a2) represented by the general formula (2). (A1) When the cloud point of a 5% aqueous solution alone is 40 ° C. or lower, (a2) is not particularly necessary, but when the cloud point of a single 5% aqueous solution is 40 ° C. or higher, (a2) ) Can be used to adjust the cloud point to 40 ° C. or lower and can be used as the oxyalkylene compound (a) of the present invention.

In the general formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group having 1 to 6 carbon atoms include linear or branched alkyl groups such as methyl, ethyl, n- or i-propyl, n-, i- or t-butyl, n-, i- or t-. Examples include pentyl and n- or i-hexyl groups. Of these, from the viewpoint of the effect of reducing drying shrinkage, an alkyl group having 1 to 4 carbon atoms is preferred, methyl and linear or branched butyl groups are more preferred, and a methyl group is particularly preferred. is there.

The oxyalkylene group having 2 to 4 carbon atoms in the general formula ^{(1) (A 1 O)} , oxyethylene group and oxypropylene group, and oxybutylene group. The propylene group includes a 1,2- or 1,3-propylene group, and the butylene group includes a 1,2-, 1,3-, 1,4- or 2,3-butylene group. Of these, oxyethylene and oxypropylene are preferred from the viewpoint of ease of production. The oxyalkylene group may be one type or a mixture of two or more types. When two or more types are mixed, the form of coupling may be block addition, random addition, or a combination thereof, but block addition is preferred.

In the general formula (1), n is an average value of 1 to 20, preferably 2 to 15, more preferably 3 to 10, particularly preferably 4 to 9. Within this range, the drying shrinkage reducing effect is further improved.
(A1) may be used in combination of two or more.

R ^{2 in the} general formula (2) is a hydrogen atom or a residue obtained by removing a hydroxyl group from a C 1-8 tetravalent saturated aliphatic alcohol. Examples of the residue obtained by removing a hydroxyl group from a monovalent to tetravalent saturated aliphatic alcohol include linear or branched alkyl groups having 1 to 6 carbon atoms, such as methyl, ethyl, n- or i-propyl, n-, i- Or t-butyl, n-, i- or t-pentyl and n- or i-hexyl, n-octyl, 2-ethyl-1-hexyl and diethylene glycol, propylene glycol, glycerin, trimethylolpropane and pentaerythritol A residue obtained by removing a hydroxyl group from the above. From the viewpoint of the effect of stabilizing the amount of air in these mortars and concrete, a residue obtained by removing a hydroxyl group from an alkyl group having 1 to 4 carbon atoms and propylene glycol, more preferably methyl, A residue obtained by removing a hydroxyl group from a butyl group and propylene glycol.

The general formula (2) odor Keru oxyalkylene group having 2 to 4 carbon atoms (A ² O), oxyethylene group and oxypropylene group, and oxybutylene group. The propylene group includes a 1,2- or 1,3-propylene group, and the butylene group includes a 1,2-, 1,3-, 1,4- or 2,3-butylene group.
From the viewpoint of the effect of stabilizing the air amount of mortar and concrete, the amount of oxypropylene group and / or oxybutylene group in (A ² O) m is usually 50 to 100 mol%, preferably 60 to 100 mol. %, More preferably 70 to 100 mol%.
The oxyalkylene group may be one type or a mixture of two or more types. When two or more types are mixed, the form of coupling may be block addition, random addition, or a combination thereof, but block addition is preferred.

M in the general formula (2) is a number up to 100 which exceeds 10 on average and is a number one or more larger than n in the general formula (1), preferably 20 to 90, more preferably 30 to The number is 80, particularly preferably 40 to 70. Within this range, the air stabilizing effect is further improved.
(A2) may be used in combination of two or more.

  When the oxyalkylene compound (a) contains the compound (a2), the weight ratio of the compound (a1) to the compound (a2) [(a1) from the viewpoint of achieving both the effect of reducing drying shrinkage and the effect of entraining an appropriate amount of air. ) / (A2)] is preferably 1 / 0.1 to 1 / 0.0001, more preferably 1 / 0.05 to 1 / 0.0005, and particularly preferably 1 / 0.01 to 1 / 0.0. 001, most preferably 1 / 0.005 to 1 / 0.002.

(A1) and (a2) are compounds in which R ¹ and R ² in general formulas (1) and (2) are substituted with a hydroxyl group (when R ¹ or R ² is a hydrogen atom, bivalent [(a2) Can be produced by adding an alkylene oxide having 2 to 4 carbon atoms to a hydroxyl group of an alcohol having 2 to 4 valences by a conventional method. Alkylene oxide is blown in the presence of a catalyst or in the presence of a catalyst (especially in the latter half of the addition reaction), and the reaction is carried out in one or more stages at normal pressure or under pressure. , Sodium, potassium, cesium, etc.)], acids [perhalogen acids (perchloric acid, perbromic acid and periodic acid), sulfuric acid, phosphoric acid, nitric acid, etc. (preferably perchloric acid), etc.], and these [Preferably, salts of divalent or trivalent metals (Mg, Ca, Sr, Ba, Zn, Co, Ni, Cu, Al, etc.)] etc. The reaction temperature is usually 50 to 180 ° C., and the reaction time is Usually 2 to 20 hours After completion of the AO addition reaction, the catalyst can be neutralized and treated with an adsorbent as necessary to remove and purify the catalyst.

The anionic surfactant (b) having 14 to 30 carbon atoms which does not have an oxyalkylene group in the present invention is a foaming component for entraining a necessary amount of air in concrete or mortar. Since it has 14 to 30 carbon atoms and does not have a group, it exhibits a synergistic effect with the oxyalkylene compound (a), so that the amount of air greatly varies depending on the kneading temperature, or the oxyalkylene compound (a) Even if a very small amount is mixed, it is possible to suppress an adverse effect such as an abnormal increase in the amount of air in the concrete.

  Examples of the anionic surfactant (b) having 14 to 30 carbon atoms not having an oxyalkylene group include a carboxylate having 14 to 30 carbon atoms, a sulfonate having 14 to 30 carbon atoms and having no oxyalkylene group. Examples thereof include sulfate ester salts having 14 to 30 carbon atoms.

  Examples of the carboxylate having 14 to 30 carbon atoms include linear or branched saturated or unsaturated carboxylate having 14 to 30 carbon atoms (myristate, palmitate, stearate, isostearic acid, arachidate, Perfate, oleate, linoleate, linolenate, etc.), carboxylate having a benzene skeleton having 14 to 30 carbon atoms [alkyl benzoate (alkyl having a total carbon number of 8 to 18 and a polysubstituted product) Etc.], carboxylates having a naphthalene skeleton having 14 to 30 carbon atoms [alkyl naphthalene monocarboxylates (including alkyls having 1 to 19 total carbon atoms) and alkyl naphthalene dicarboxylates (alkyl Etc.), and may be substituted with an aliphatic hydrocarbon group having 1 to 15 carbon atoms, and part or all of them may be hydrogenated. Carboxylate having a phenanthrene skeleton (phenanthrenecarboxylate, abietic acid salt, neoabietic acid salt, dihydroabietic acid salt, tethylahydroabietic acid salt, d-pimaric acid salt, iso-d-pimalic acid Salt, dehydroabietic acid salt, levopimarate, and these maleated derivatives).

  Examples of the sulfonate having 14 to 30 carbon atoms include alkyl (8 to 24 carbon) benzene sulfonate, alkyl (4 to 20 carbon) naphthalene sulfonate, and alkyl (2 to 18 carbon) diphenyl ether sulfonate. And phenanthrene sulfonate.

Examples of the sulfate salt having 14 to 30 carbon atoms include dodecyl sulfate ester salt, tetradecyl sulfate ester salt, cetyl sulfate ester salt, octadecyl sulfate ester salt, sulfate ester salt of styrenated phenol, sulfate ester salt of benzylated phenol, styrenation Examples thereof include sulfates of cumylphenol and sulfates of benzylated cumylphenol.
(B) may be used in combination of two or more.

  Examples of the cation component in the salt include a monovalent cation and a polyvalent (2 to 7 valent) cation, and these may be used alone or in combination of two or more.

  Examples of the monovalent cation include an ammonium cation having 0 to 25 carbon atoms, an amine cation having 1 to 15 carbon atoms, and an alkali metal cation.

  Examples of the ammonium cation having 0 to 25 carbon atoms include ammonium, tetramethylammonium, trimethylvinylammonium, trimethylphenylammonium, benzyltriethylammonium, dodecyltrimethylammonium, tetrabutylammonium, trimethyltetradecylammonium, benzyltributylammonium, tetrapentylammonium, Examples include ethyl hexadecyldimethylammonium and octadecyltrimethylammonium.

  The amine cation having 1 to 15 carbon atoms is obtained by adding a proton to an amine having 1 to 15 carbon atoms. Examples of the amine having 1 to 15 carbon atoms include methylamine, ethylamine, isopropylamine, dimethylamine, trimethylamine, and diethanolamine. , 2-pyridineamine, cis-3-methylcyclohexylamine, benzylamine and 1,8-diazabicyclo [5.4.0] -7-undecene, 1,5-diazabicyclo [4.3.0] -5-nonene And amidine such as 2-methylimidazole, 2-butylbenzimidazole and 2- (4-thiazolyl) benzimidazole.

  Examples of the alkali metal cation include a lithium cation, a sodium cation, and a potassium cation.

  Examples of the polyvalent (2 to 7 valent) cation include a polyvalent (2 to 7 valent) amine cation and an alkaline earth metal cation having 2 to 36 carbon atoms.

   A C2-C36 polyvalent (2-7 valent) amine cation is obtained by adding a proton to a C2-C36 polyvalent (2-7 valent) amine. (2-7 valent) amines include ethylenediamine, 1,5-pentanediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, polyethyleneimine, paraphenylenediamine, and triaminonaphthalene. And triaminoanthracene.

Examples of alkaline earth metal cations include calcium cations and magnesium cations.
Among these cations, an alkali metal cation is preferable from the viewpoint of little influence on the setting of cement, and lithium cation, sodium cation and potassium cation are more preferable, and lithium cation and sodium cation are particularly preferable.

  From the viewpoint that the effect of stabilizing the amount of air is high when used in combination with the oxyalkylene compound (a), a carboxylate having 14 to 30 carbon atoms is preferred as (b), and more preferred is carbon. Carboxylic acid salts having a phenanthrene skeleton which may be substituted with aliphatic hydrocarbon groups of 1 to 15 and partially or entirely hydrogenated, particularly preferred are abietic acid salts and neoabietic acid Acid salts, dihydroabietic acid salts, tethyrahydroabietic acid salts, d-pimaric acid salts, iso-d-pimalic acid salts, dehydroabietic acid salts and levopimaric acid salts, and most preferred are abietic acid salts.

  The weight ratio [(a) / (b)] of the oxyalkylene compound (a) and the anionic surfactant (b) is 1/2 from the viewpoint of achieving both the effect of reducing drying shrinkage and the effect of entraining an appropriate amount of air. 0.01 to 1 / 0.0001 is preferable, more preferably 1 / 0.008 to 1 / 0.0005, particularly preferably 1 / 0.007 to 1 / 0.001, and most preferably 1 / 0.005. ~ 1 / 0.002.

The cement composition of the present invention comprises the cement additive of the present invention, cement, water, and aggregate as essential components. For example, the concrete standard specifications established by the Japan Society of Civil Engineers and the Architectural Institute of Japan established by the Architectural Institute of Japan. It can be produced by a publicly known facility or a publicly known method in accordance with the created construction standard specifications. The means for adding the cement additive may be the same as that of a commonly used cement admixture. For example, after mixing the cement additive in the kneaded water in advance, other raw materials may be added. Alternatively, it may be put together with other raw materials into a mixer.
Further, the cement additive of the present invention comprises an oxyalkylene compound (a) comprising the compound (a1) and, if necessary, the compound (a2), an anionic surfactant having 14 to 30 carbon atoms having no oxyalkylene group ( b), but when the cement composition of the present invention is produced, a combination of (a) and (b) in advance may be added, or each component may be added separately. Good. In addition to (a) and (b), for example, water or a mixture with other admixtures such as a water reducing agent for cement may be added.

The cement used in the cement composition of the present invention includes ordinary hydraulic cements [ordinary Portland cement, special Portland cement (early strong Portland cement, moderately hot Portland cement and Belite cement) and mixed cement (blast furnace cement, fly Ash cement and silica cement)] and the like.
Examples of the kneaded water include seawater, river water, lake water, tap water, industrial water, and deionized water.
Aggregates include fine aggregates and coarse aggregates. As fine aggregates, aggregates conforming to JIS A5308: 1998 Annex 1 (normative) ready-mixed concrete aggregates can be used, such as river sand, land sand, mountain sand, sea sand and crushed sand. It is done. As the coarse aggregate, there can be used an aggregate or the like that conforms to Annex 1 (normative) ready mixed concrete aggregate of JIS A5308: 1998, and examples thereof include river gravel, land gravel, mountain gravel and crushed stone.

  Furthermore, known cement admixtures and admixtures can be added to the cement composition of the present invention. Examples of the admixture include fly ash, blast furnace slag, silica fume, and an expansion material. Admixtures include water reducing agents (AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents and fluidizing agents), air entraining agents (AE agents), foaming agents (foaming agents), antifoaming agents (foam suppression agents). Agents and foam breakers), curing accelerators (rapid setting agents), curing retarders, rust inhibitors, thickeners, polymer dispersions for polymer cement concrete or polymer mortar, and other admixtures.

  Fly ash conforming to JIS A6201: 1999 concrete fly ash, blast furnace slag conforming to JIS A6206: 1997 concrete blast furnace slag fine powder, silica fume conforming to JIS A6207: 2000 concrete silica fume Etc. can be used. Examples of the expansion material include calcium sulfoaluminate and quicklime [for example, Denka CSA (manufactured by Denki Kagaku Kogyo) and Asanodipkar (manufactured by Taiheiyo Material)].

  Examples of water reducing agents include lignin sulfonates (alkaline metal salts such as sodium and alkaline earth metal salts such as calcium; the same applies to salts of the following compounds), naphthalene sulfonic acid formalin condensate (condensation degree: 5 to 5). 20), melamine formalin condensate salt (condensation degree: 5 to 20), polycarboxylate (number average molecular weight: 5000 to 60,000), aminosulfonic acid formalin condensate salt (condensation degree: 2 to 20), And a polyoxyalkylene group (for example, a polyoxyalkylene group having 2 and / or 3 carbon atoms in the alkylene group) -containing polycarboxylate (number average molecular weight: 10,000 to 600,000) [for example, development technology of concrete admixture, CMC Co., Ltd., published in 1995].

  Although the cement additive of the present invention itself has air entrainment properties, a known air entrainment agent (AE agent) can also be used in combination to further finely adjust the amount of air. Examples of the air entraining agent include alkyl sulfate esters, polyoxyalkylene alkyl ether sulfates, resin acid salts (such as abietic acid), and the like.

Examples of the foaming agent include alkyl sulfate ester salts, alkyl ether sulfate ester salts, alkylbenzene sulfonates, and protein foaming agents.
Antifoaming agents include ester-based antifoaming agents, polyether-based antifoaming agents, mineral oil-based antifoaming agents, silicone-based antifoaming agents, and powder antifoaming agents [for example, introduction to new surfactants, Sanyo Chemical Industries ( Co., Ltd., published in 1981, SN deformer 14HP and SN deformer 11-P (manufactured by San Nopco)].

  Examples of the curing accelerator include diethanolamine, triethanolamine, calcium chloride, and other known curing accelerators. Examples of the curing retarder include sugars and oxycarboxylates. Examples of the rust inhibitor include nitrite. Examples of the thickener include polyacrylamide and cellulose ether. Examples of the polymer dispersion for polymer cement concrete or polymer mortar include styrene butadiene rubber latex, ethylene vinyl acetate, and polyacrylate emulsion. Examples of other admixtures include known mortars or concrete admixtures (for example, those described in the development technology of concrete admixture, CMC Co., Ltd., issued in 1995).

The amount of use (% by weight) of the cement additive of the present invention is preferably 0.5 to 20, more preferably 1 to 5, based on the weight of the cement, from the viewpoint of efficiently exhibiting the drying shrinkage reduction effect. 10, particularly preferably 1.5 to 7.5, most preferably 2 to 5.
The amount of cement, water, and aggregate used in the cement composition is not particularly limited, and is the amount normally used (for example, the amount described in the Standard Specification for Concrete established by the Japan Society of Civil Engineers). I just need it.
There is no restriction | limiting in particular in the usage-amount of a well-known cement admixture and admixture, What is necessary is just the range normally used.

  The construction method of the cement composition (mortar, concrete, etc.) of the present invention may be the same as in the conventional case. Moreover, as a hardening thru | or curing method, any of an air-drying curing, a wet-air curing, an underwater curing, a heat promotion curing (steam curing and an autoclave curing) may be sufficient, and each combined use may be sufficient.

[Example]
Hereinafter, the present invention will be further described with reference to examples, but the present invention is not limited thereto. Unless otherwise specified, parts are parts by weight, and% is% by weight.

<Synthesis Example 1>
148 parts (1 mol part) of dipropylene glycol monomethyl ether and 0.5 part of potassium hydroxide are charged into a pressure-resistant reaction vessel equipped with a stirrer and a temperature control function, and the gas phase part in the system is nitrogenated at 25 ° C. with stirring. After being adjusted to 150 ° C., dripping of 174 parts (3 mol parts) of propylene oxide was started at 150 ° C. under reduced pressure (gauge pressure: −0.05 MPa). The reaction was continued until the pressure change in the system disappeared while controlling the gauge pressure to be 0.1 to 0.3 MPa. After cooling to 25 ° C., potassium hydroxide was removed by adsorption treatment to obtain 322 parts of a propylene oxide 5 mol adduct (A1) of methanol.
<Synthesis Example 2>
Methanol was prepared in the same manner as in Synthesis Example 1, except that 148 parts (1 mole part) of dipropylene glycol monomethyl ether was replaced with 76 parts (1 mole part) of ethylene glycol monomethyl ether and the number of parts of propylene oxide was 464 parts (8 mole parts). 540 parts of ethylene oxide 1 mol propylene oxide 8 mol block adduct (A2) was obtained.

<Synthesis Example 3>
Synthesis except that 148 parts (1 mole part) of dipropylene glycol monomethyl ether is replaced with 90 parts (1 mole part) of propylene glycol monomethyl ether and 174 parts (3 mole parts) of propylene oxide is replaced with 132 parts (3 mole parts) of ethylene oxide. In the same manner as in Example 1, 222 parts of methanol propylene oxide 1 mol ethylene oxide 3 mol block adduct (A3) was obtained.
<Synthesis Example 4>
Methanol was prepared in the same manner as in Synthesis Example 1, except that 148 parts (1 mole part) of dipropylene glycol monomethyl ether was replaced with 76 parts (1 mole part) of ethylene glycol monomethyl ether and the number of parts of propylene oxide was 232 parts (4 mole parts). 308 parts of ethylene oxide 1 mol propylene oxide 4 mol block adduct (A4) was obtained.

<Synthesis Example 5>
Except for replacing 148 parts (1 mole part) of dipropylene glycol monomethyl ether with 190 parts (1 mole part) of dipropylene glycol monobutyl ether and 174 parts (3 mole parts) of propylene oxide with 88 parts (2 mole parts) of ethylene oxide. In the same manner as in Synthesis Example 1, 278 parts of butanol propylene oxide 2 mol ethylene oxide 2 mol block adduct (A5) was obtained.
<Synthesis Example 6>
In the same manner as in Synthesis Example 1 except that 0.5 part of potassium hydroxide is replaced with 2.5 parts and the number of parts of propylene oxide is 1624 parts (28 moles), 1772 parts of methanol propylene oxide 30 mole adduct (A6) Got.

<Synthesis Example 7> (Synthesis of water reducing agent G1)
Into a four-necked flask into which nitrogen gas was introduced into the liquid through an introduction tube, 1,040 parts (1 mole part) of polyoxyethylene (ethylene oxide average addition mole number 22) monomethyl monoallyl ether, 98 parts of maleic anhydride (1 Mol part) and 500 parts of toluene were charged and dissolved. Subsequently, 12 parts of benzoyl peroxide was charged, and the reaction was carried out at 70 ° C. for 10 hours under nitrogen flow. After completion of the reaction, toluene was distilled off at 100 ° C. under reduced pressure to obtain a copolymer having a weight average molecular weight of 12,000. Subsequently, after cooling to 40 ° C., 4655 parts of water and 267 parts of 30% aqueous sodium hydroxide solution were added and stirred for 10 minutes, and polyoxyethylene (ethylene oxide average added mole number 22) monomethyl monoallyl ether / maleic anhydride 6060 parts of a 20% solid content aqueous solution (G1) of neutralized sodium hydroxide of the polymer was obtained.
The weight average molecular weight was measured by the gel permeation chromatography (GPC) method under the following conditions (hereinafter the same).
Measuring equipment: GPC system manufactured by Waters [pump; Model 510, detector: waters 410]
Eluent: Type Water / methanol (70/30 (volume ratio)) + sodium acetate [5 g / liter (vs. water / methanol)]
Flow rate 1.0 (ml / min)
Column: TSKgel G3000 (7.8 mm ID. × 30 cm) PWXL + TSKGel G6000 PWXL (7.8 mm ID. × 30 cm)
Column temperature: 40 ° C
Standard substance: polyethylene glycol [weight average molecular weight: 2.4 × 10 4, 5.0 × 10 4, 1.0
7 × 10 5, 2.5 × 10 5, 5.4 × 10 5, 9.0 × 10 5 (TSK standard polyethylene oxide SE-2, SE-5, SE-8, SE-30, SE-70, manufactured by Tosoh Corporation) SE-150)].

<Synthesis Example 8> (Synthesis of water reducing agent G2)
After charging 1309 parts of water into a four-necked flask, 496 parts (3 mole parts) of methoxypolyoxyethylene (ethylene oxide average added mole number 9) methacrylate and 172 parts of methacrylic acid (2 mole parts) under flowing nitrogen at 100 ° C. ), A mixture of 1 part of mercaptoethanol and 619 parts of water, and a mixed solution of 14.3 parts of sodium persulfate and 225 parts by weight of water each continuously in 3 hours to give a copolymer having a weight average molecular weight of 10,000 Got. Subsequently, after cooling to 40 ° C., 532.7 parts of water and 267 parts of a 30% aqueous sodium hydroxide solution were added and stirred for 10 minutes to obtain methoxypolyoxyethylene (ethylene oxide average added mole number 9) methacrylate / methacrylic acid copolymer. 3636 parts of a 20% solid content aqueous solution (G2) of a neutralized sodium hydroxide product was obtained.

<Examples 1-5 and Comparative Examples 1-4>
(A1) to (A6) obtained in the above synthesis example, (A7) and (B1) to (B3) shown below were charged into a beaker at a weight ratio described in Table 1, and mixed at 25 ° C. for 10 minutes. The cement additive of the present invention and a comparative cement additive were obtained. In addition, about the (a) component [(A1)-(A7) or the mixture based on the weight ratio described in Table 1] in the above-mentioned cement additive, the blended with water so that the concentration becomes 5% Table 1 shows the results of measuring the cloud point of the product and the results of visual observation after standing at 25 ° C. for 24 hours after blending.
(A7): Polyoxypropylene glycol [New Paul PP-3000, manufactured by Sanyo Chemical Industries, Ltd., average molecular weight based on hydroxyl value of about 3000]
(B1): sodium abietic acid (B2): sodium oleate (B3): polyoxyethylene lauryl ether sulfate sodium salt [Sandet EN, manufactured by Sanyo Chemical Industries, Ltd.]

  The cement additive in the amount shown in Table 1 with respect to the cement weight and the water reducing agent in the amount shown in Table 1 in terms of solid content with respect to the cement weight were previously mixed in the kneading water. Cement, standard sand adjusted to the material temperatures listed in Table 1 (10 ° C, 20 ° C and 30 ° C), standard sand (JIS A5201: 1997 Annex 2 cement test method-sand conforming to strength measurement ) And kneading water to which the above cement additive and water reducing agent are added are mixed and kneaded so that the weight ratio of cement / standard sand = 1/2 and the water cement ratio (kneading water / cement ratio) = 0.42. Thus, a cement composition was obtained. Table 1 shows the amount of air measured for each cement composition in accordance with the method for measuring the amount of mortar air specified in JIS A5308: 1998 Annex 3 Mortar Compressive Strength Sand Test Method.

  The cement composition was poured into three metal molds each having a size of 4 × 4 × 16 cm, demolded 24 hours later, then cured in water at 20 ° C. for 7 days, and further in an atmosphere of 20 ° C. and 65% RH. 7 days, 14 days, 21 days and 28 days. JIS A1129-3: 2001 (Test method for changing the length of mortar and concrete-Part 3 Dial Gauge) Immediately after taking out from underwater curing and in each day of standing in an atmosphere of 20 ° C and 65% RH Table 1 shows values obtained by measuring the shrinkage rate as the length change rate and averaging the three length change rates.

  From Table 1, when the cement additive of the present invention is used, an appropriate amount of air can be entrained, the influence of the mortar kneading temperature on the air entrainment is extremely small, and the drying shrinkage reduction effect is also excellent. I understand.

  The cement additive of the present invention includes a cement composition containing a normal hydraulic cement [ordinary Portland cement, special Portland cement (early strong Portland cement and moderately hot Portland cement), mixed cement (blast furnace cement and fly ash cement), etc.] Applicable to things. In particular, compared to the case where a conventional drying shrinkage reducing agent for cement is added, the effect of the kneading temperature on air entrainment and the effect of the amount of drying shrinkage reducing agent on air entrainment are small. Suitable for general mortar and concrete blending.

Claims (6)

An oxyalkylene compound (a) comprising the compound (a1) represented by the general formula (1) and, if necessary, the compound (a2) represented by the general formula (2), and an anion having 14 to 30 carbon atoms having no oxyalkylene group A cement additive comprising a surfactant (b), wherein (a) is dissolved or uniformly dispersed in water at an arbitrary ratio at room temperature, and the 5% aqueous solution of (a) is clouded Cement additive whose point is 40 ° C. or lower.
R ¹ O (A ¹ O) nH (1)
[Wherein, R ¹ is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, A ¹ O is an oxyalkylene group having 2 to 4 carbon atoms, n is an average value of 1 to 20 and n is 2 or more. In this case, n A ¹ Os may be the same or different. ]
R ² O (A ² O) mH (2)
[In the formula, R ² is a hydrogen atom or a residue obtained by removing a hydroxyl group from a C 1-8 tetravalent saturated aliphatic alcohol, A ² O is a C 2-4 oxyalkylene group, (A ² O) 50 to 100 mol% in m is an oxypropylene group and / or oxybutylene group, and m is a number up to 100 which is an average value exceeding 10 and a number which is 1 or more larger than n in the general formula (1). And the m pieces of A ² O may be the same or different. ]   The oxyalkylene compound (a) comprises the compound (a1) and the compound (a2), and the weight ratio [(a1) / (a2)] of the compound (a1) to the compound (a2) is 1 / 0.0. The cement additive according to claim 1, which is 1-1 / 0.0001.   The anionic surfactant (b) is a carboxylate having a phenanthrene skeleton which may be substituted with an aliphatic hydrocarbon group having 1 to 15 carbon atoms and may be partially or wholly hydrogenated. The cement additive according to claim 1 or 2.   The weight ratio [(a) / (b)] of the oxyalkylene compound (a) and the anionic surfactant (b) is 1 / 0.01 to 1 / 0.0001. Or an additive for cement.   A cement composition comprising the cement additive according to any one of claims 1 to 4, cement, water, and an aggregate.   The cement composition according to claim 5, wherein the amount of the additive for cement is 0.5 to 20% by weight based on the weight of cement.