JP3124183B2 - Cement dispersant - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cement dispersant having a slump loss preventing performance. More specifically, an additive that is added to a cement composition such as cement, mortar, concrete, etc. to improve its flowability, prevent a decrease in flowability with time (hereinafter referred to as slump loss), and improve workability. It is about.

[0002]

2. Description of the Related Art In order to improve the workability of cement paste, mortar or concrete as a cement compound, it is necessary that the cement compound has a high initial fluidity and a small change over time in fluidity.

[0003] Cement paste, which is a cement compound,
Mortar or concrete, due to the hydration reaction of cement or the like, loses its fluidity with the lapse of time after compounding, resulting in a decrease in workability and workability. This phenomenon is generally called slump loss. The slump loss of the cement mix is limited in the case of ready-mixed concrete, which limits the transport time,
Problems such as quality deterioration and poor construction due to the standby time at the casting site, temporary interruption of pumping, etc. are caused. Also, in the case of a concrete secondary product, the molding time is limited and centrifugal compaction failure occurs due to slump loss of the concrete. Therefore, slump loss in cement formulations was an important issue that had to be solved.

[0004] In order to solve these problems, a slump loss preventing type cement dispersant for a cement compound has been proposed. For example, a copolymer of an olefin and an ethylenically unsaturated dicarboxylic anhydride (JP-A-60-1685)
There is a cement dispersant containing a water-insoluble structural part such as No. 1). However, these are dispersants composed of a liquid containing fine particles, and have problems in non-uniform quality and stability over time.

Further, a condensate of an aromatic aminosulfonic acid and formalin has been reported (Japanese Patent Laid-Open No. 1-1341).
No. 9), the slump loss prevention performance was still insufficient.
Further, a large number of polycarboxylic acid salts have been reported (for example, Japanese Patent Publication No. 63-10107), but those which exhibit slump loss prevention performance have a problem that the setting time is extremely long.

Further, there have been many applications of copolymers of polyoxyalkylene unsaturated esters or ethers with unsaturated carboxylic acids (see, for example, JP-A-4-175253).
No., Japanese Patent Publication No. 2-7898, Japanese Patent Publication No. 2-7901),
These also have a problem that they have a large setting retardation.

Japanese Patent Application Laid-Open No. 62-216950 discloses that
5 to 40% by weight of a vinyl polymer having a sulfonic acid salt, 90 to 30% by weight of a vinyl polymer having a carboxylic acid salt, and 5 to 30% by weight of a vinyl polymer having a glycol as a side chain. Dispersants for cements having three specific structural units are disclosed,
JP-A 1-222657 discloses that a vinyl polymer having 3 to 25% by weight of a sulfonic acid as a side chain, a 10 to 50% by weight of a vinyl polymer having a salt of a carboxylic acid, and a vinyl polymer having a glycol A cement dispersant having three types of specific constituent units consisting of 40 to 80% by weight is disclosed, and the description “If the reaction ratio of each monomer is out of the above range, the resulting water-soluble vinyl When the copolymer is used as a dispersant for cement, the initial effect is not expected due to insufficient dispersion fluidity, large slump loss, or excessive air volume. '' . But there is a problem that with these dispersants tossed the condensation to delayed.

As described above, conventionally known uniform liquid slump loss prevention type cement dispersants have a problem that slump loss prevention performance is low, and those having high slump loss prevention performance have a large setting delay property. Was inadequate.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned disadvantages of the prior art, and can be incorporated into a cement composition to increase its flowability and prevent slump loss, while at the same time causing no setting delay. The purpose is to provide a uniform liquid drug.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies on the prevention of slump loss and the prevention of setting delay in a cement composition, and have found that a vinyl compound having a polyoxyalkylene chain and a vinyl compound having a sulfonic acid group can be used. The present invention has been accomplished by finding that the copolymer is extremely effective. Further, a copolymer having three types of specific structural units consisting of a vinyl compound having a sulfonic acid as a side chain, a vinyl compound having a salt of a carboxylic acid, and a vinyl compound having a glycol, It has been surprisingly found that when the proportion of the vinyl compound having a salt is reduced and the proportion of the vinyl compound having a sulfonic acid is increased, the ability to prevent slump loss is high and the setting retardation is reduced. Another performance as a cement dispersant is disclosed in JP-A-62-216950.
In spite of the fact that the performance is worsened in Japanese Patent Application Laid-Open No. Hei. Further investigations have found a composition which is extremely effective as a cement dispersant, and have completed the present invention.

[0011]

That is, a first invention of the present invention provides a structural unit represented by the following general formula (I) and the following general formula (II)
A water-soluble vinyl polymer containing a structural unit represented by the following general formula (III) and a structural unit represented by the following general formula (III), and a structural unit represented by the formula (I) / a formula (II) Structural unit / content of structural unit represented by formula (III) is from 40 to
89/10 to 59/1 to 50% by weight, a cement dispersant that prevents slump loss and does not cause setting delay.

Further, the second invention of the present invention provides a structural unit represented by the following general formula (I), a structural unit represented by the following general formula (III), and a structural unit represented by the following general formula (IV) A water-soluble vinyl polymer containing a structural unit, which is represented by the formula (I)
The structural unit represented by the formula / the structural unit represented by the formula (IV) is 3
The weight ratio is 0/70 to 90/10, and the structural unit represented by the formula (III) is 50% by weight or less, and the structural unit represented by the formula (I) is 50% by weight or more. Is a cement dispersant. here,

Embedded image Wherein R ¹ and R ² represent hydrogen or a methyl group, M represents an alkali metal, an alkaline earth metal, an ammonium group or a salt of an organic amine such as a lower alkylamine or ethanolamine;

Embedded image (R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ each independently represent hydrogen or a methyl group.) ]

Embedded image Wherein R ³ and R ⁴ are hydrogen or a methyl group, R ⁵ is hydrogen or an alkyl group having 1 to 3 carbons, n is 2 or 3,
m an integer of from 1 100, Y is -CH ₂ - or -C
O- is independently represented. ] (Your R ⁵ in the case of the first aspect of the present invention
And Y will be described later)

Embedded image [However, R ⁶ is hydrogen or a methyl group, R ⁷ is hydrogen, a methyl group or —CH ₂ COOM, K is hydrogen or —CO 2
OM are each independently represented, M is the same as above, and R
⁷ when the -CH ₂ COOM K is hydrogen. ]

Embedded image Wherein R ⁸ and R ⁹ each independently represent hydrogen or a methyl group, and Z is

Embedded image [In the formula, A represents an alkylene group having 2 to 3 carbon atoms, l, m, and n represent a number of 1 to 100, and m + n represents a number of 2 to 100. ]

[0014]

[0015] The first aspect of the present invention is, as state like its,
And Y is -CO- in formula (II), including cement dispersant R ⁵ is an alkyl group having 1 to 3 carbon atoms (referred to first outgoing <br/> bright aspect 1).

The first aspect of the present invention, and as other state-like, Y in the general formula (II) is -CH ₂ - or -CO-
And R ⁵ is hydrogen (referred to as Embodiment 2 of the first invention).

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

[0018] In the vinyl polymer used in the present invention, Exemplary monomers forming the structural unit represented by the formula (I), porcine diene sulfonic acid, conjugated diene sulfonated isoprene sulfonic acid, styrene sulfonic acid ,
styrene sulfonic <br/> acid such as α- methyl styrene sulfonic acid, Contact and salts thereof. Salts include alkali metal salts, alkaline earth metal salts, ammonium salts, organic amine salts, and the like, with alkali metal salts being preferred.

Examples of the monomer forming the structural unit represented by the formula (II) include methoxypolyethylene glycol, ethoxypolyethyleneglycol, propoxypolyethyleneglycol, methoxypolyethylenepolypropylene glycol, ethoxypolyethylenepolypropyleneglycol and the like. An esterified product of an alkylene glycol and an unsaturated monocarboxylic acid such as acrylic acid or methacrylic acid, wherein the number of moles of the polyalkylene glycol added is 1 to 100, preferably 5 to 5.
What is 0 is used.

In addition, unsaturated acids such as acrylic acid and methacrylic acid
Monocarboxylic acids and H (OC_nH _2n)_mIndicated by OH
Glycols and monoesters and unsaturated monocarboxylic acids
Made by adding ethylene oxide or propylene oxide to boric acid
Monoester, polyalkylene glycol mono
Allyl ether and the like are used. That is, in the present invention
In the vinyl polymer used, the structure represented by the formula (II)
Examples of the monomer forming the unit include ethylene glycol.
Alkylene glycos such as coal and propylene glycol
To ethylene oxide and propylene oxide
Of alkylene oxides alone or as a mixture
Polyalkylene glycol monoacrylate,
Nomethacrylate, monoallyl ether, monomethacrylate
Ruether and the like.

Examples of the monomer forming the structural unit represented by the formula (III) include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, maleic acid,
Unsaturated dicarboxylic acids such as fumaric acid, citraconic acid, mesaconic acid, and itaconic acid, and salts thereof. The salts are the same as described above.

Examples of the monomer forming the structural unit represented by the formula (IV) include an amide compound prepared by adding ethylene oxide or propylene oxide to an unsaturated monocarboxylic acid amide such as acrylamide or methacrylamide. And one or more of these can be used. Here, the number of moles of the alkylene oxide to be added is suitably from 1 to 100, preferably from 5 to 20, and the use of a monomer added more than that is not preferable because the yield decreases.

[0023]

The polymer of the first invention of the present invention has the formula (I):
It is essential to contain the structural units represented by (II) and (III), and the content ratio of each structural unit is determined by the formula (I)
It is necessary that the ratio of the structural unit of formula (II) / the structural unit of formula (II) / the structural unit of formula (III) is in the range of 40 to 89/10 to 59/1 to 50% by weight. More preferably 40 to 80/2
0 to 55/1 to 40. When the constitutional unit of the formula (I) decreases and the constitutional unit of the formula (III) increases from this range, the setting retardation becomes remarkable, which is not preferable as a cement dispersant. If the proportion of the structural unit of the formula (II) is out of this range, the dispersibility of the cement or the ability to prevent slump loss will deteriorate.

The polymer of the second invention of the present invention has the formula (I):
Each of the structural units represented by (III) and (IV) is contained, and the content ratio of each structural unit is represented by the following formula / I.
The structural unit represented by (IV) has a weight ratio of 30/70 to 90/10, preferably 30/70 to 80/20, and the structural unit represented by the formula (I) is at least 50% by weight. , The structural unit represented by the formula (III) must be 50% by weight or less. If the content is out of this range, the setting retardation becomes remarkable, and the dispersibility of the cement or the prevention of slump loss deteriorates.

In the polymer of the present invention, in addition to the above essential components, other unsaturated monomers can be copolymerized within a range not to impair the performance of the present invention. Examples of such a monomer include alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate and butyl methacrylate, vinyl aromatic compounds such as styrene and indene, and isobutylene. , Olefins such as isoprene, acrylamide,
There are maleic anhydride, itaconic anhydride and the like. Further, examples of the copolymerizable monomer include unsaturated dicarboxylic anhydrides such as maleic anhydride and itaconic anhydride and unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid;
(OC _n H _2n) monoesters and the glycol represented by _m OH, monoester made by adding ethylene oxide or propylene oxide to unsaturated monocarboxylic acids,
And polyalkylene glycol monoallyl ether.

The weight average molecular weight of the polymer of the present invention is preferably from 1,000 to 100,000 (GPC method, in terms of sodium polystyrene sulfonate).
If it is higher than this, the dispersibility tends to be insufficient when the cement composition is used, and if it is smaller than this, the dispersibility tends to be insufficient and the slump loss tends to increase.

The method for producing the polymer of the present invention is not particularly limited in the present invention, and any conventionally known method can be applied. For example, radical polymerization is generally used to form the reaction, and it is preferable to carry out the reaction in water or an alcohol such as methyl alcohol, ethyl alcohol, or isopropanol. As the polymerization initiator, a peroxide such as benzoyl peroxide, an azo compound represented by azobisisobutyronitrile, and a persulfate can be used.

The cement dispersant of the present invention can be added to a cement mixture such as a cement paste composed of cement and water, a mortar composed of cement, sand and water, a concrete composed of cement, sand, pebbles and water. The dispersant of the present invention can be used in combination with other components as needed. Such other components include salts of naphthalenesulfonic acid formalin condensate, ligninsulfonic acid,
Other dispersants such as melamine sulfonic acid, air entrainers, defoamers, setting accelerators, setting retarders, swelling agents, shrinkage reducing agents,
Preservatives and the like.

The cement dispersant of the present invention is 0.01 to 2% by weight, preferably 0.1 to 2% by weight, as solids, based on cement.
It is used in a proportion of 0.5 to 1% by weight. If the amount used is too small, the dispersion fluidity of the cement composition decreases,
Slump loss increases. On the other hand, if the used amount is too large, material separation occurs or curing failure occurs.

Hereinafter, the present invention will be described in more detail with reference to Examples, but it should be understood that the present invention is by no means restricted to such specific Examples. Parts are parts by weight unless otherwise specified.

[0032]

EXAMPLES <Synthesis Example 1> methallyl sodium sulfonate 15 parts (parts by weight, hereinafter the same), methoxy polyethylene glycol monomethacrylate (moles of ethylene oxide added n = 9) 15 parts,
70 parts of sodium acrylate was charged into a four-necked flask equipped with a thermometer, a dropping funnel, a nitrogen gas inlet tube, and a stirrer, and further 200 parts of water was added to uniformly dissolve the same. Until heated. A solution prepared by dissolving 3.5 parts of ammonium persulfate in 10 parts of water was added dropwise to start polymerization, and the reaction was completed at 4 hours while maintaining the reaction temperature at 90 ° C. Thus, Comparative Copolymer 1 having a weight average molecular weight of 15,000 was obtained.

<Synthesis Example 2> 75 parts of sodium p-styrenesulfonate (parts by weight, the same applies hereinafter), 5 parts of sodium acrylate and 30 parts of methoxypolyethylene glycol monomethacrylate (the number of moles of ethylene oxide added n = 8) were measured with a thermometer. The mixture was charged into a four-necked flask equipped with a dropping funnel, a nitrogen gas inlet tube, and a stirrer, and 200 parts of water was further added to uniformly dissolve the mixture. The mixture was heated to 85 ° C. while replacing the atmosphere with nitrogen. A solution prepared by dissolving 3.5 parts of ammonium persulfate in 10 parts of water is added dropwise to initiate polymerization. Further, when the reaction temperature is 9
The reaction was completed at 0 ° C. for 4 hours. In this way,
Copolymer with weight average molecular weight of 48,000 (Copolymer 1)
I got Similarly, copolymers 2 to 6 shown in Table 1 were obtained.

<Synthesis Example 3> 75 parts (parts by weight, hereinafter the same) of sodium p-styrenesulfonate, 5 parts of sodium methacrylate and 20 parts of polyethylene glycol monomethacrylate (the number of moles of ethylene oxide added n = 8) were measured with a thermometer. The mixture was charged into a four-necked flask equipped with a dropping funnel, a nitrogen gas inlet tube, and a stirrer, further dissolved in 200 parts of water by adding 200 parts, and heated to 85 ° C. while replacing the atmosphere with nitrogen. A solution prepared by dissolving 3.5 parts of ammonium persulfate in 10 parts of water is added dropwise to initiate polymerization. Further, the reaction temperature was kept at 90 ° C. to complete the reaction for 4 hours. Thus, a copolymer having a weight average molecular weight of 52,000 (copolymer 7 ) was obtained.
Similarly, copolymers 8 to 12 shown in Table 2 were obtained.

<Synthesis Example 4> An adduct obtained by reacting 75 parts (parts by weight, the same applies hereinafter) of sodium p-styrenesulfonate so that the average number of moles of ethylene oxide added per molecule of acrylamide is 10 moles ( In the following, 20 parts of acrylamide EO 10 mol adduct) and 5 parts of sodium methacrylate were charged into a four-necked flask equipped with a thermometer, a dropper, a nitrogen gas inlet tube, and a stirrer, and 200 parts of water was further added to uniformly mix the mixture. It was melted and heated to 85 ° C. while replacing the atmosphere with nitrogen. A solution prepared by dissolving 3.5 parts of ammonium persulfate in 10 parts of water is added dropwise to initiate polymerization. Further, the temperature of the reaction was kept at 90 ° C., and after 4 hours, the reaction was completed. Thus, a copolymer having a weight average molecular weight of 60,000 (copolymer 13 ) was obtained. Table 3 shows copolymers 14 to 17 synthesized in the same manner.

<Concrete test> The copolymers and NSFs described in Tables 1 to 3 were respectively used.
(Naphthalenesulfonic acid formalin condensate sodium
Salt), SMA (styrene / maleic anhydride copolymer)
Hydrolyzate (sodium salt) or ratio obtained in Synthesis Example 1
Using Comparative Copolymer 1 , blended under the blending conditions shown in Table 4 ,
Concrete tests were carried out on the blends under the following conditions to measure slump and air content, their aging, setting time, and compressive strength. The method for measuring the slump value, air volume, compressive strength and setting time and collecting the compressive strength specimens are described in J.
Performed according to ISA6204. Table 5-6 shows the test results.
Shown in

The concrete shown in Table 4 was prepared using a 50-L forced kneading mixer, cement, fine aggregate, coarse aggregate,
After mixing the water in which the dispersant of the present invention was dissolved for 2 minutes, the mixture was paid out to a kneading vat and kneaded again. Furthermore, the measurement of the slump value and the amount of air after 60 minutes was performed after the still concrete was kneaded. The air amount immediately after kneading is 4.5 ± 0.5% by volume using an air conditioner, a commercially available air entraining agent and / or an antifoaming agent as required.
Was adjusted.

[0038]

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042] Cement: Ordinary Portland cement (Mitsubishi Materials Corporation) Fine aggregate: Mixed sand (coarse sand / fine sand = 8/2 (weight ratio))
Specific gravity: 2.56, FM = 2.83) Rough sand: Nakagawa, Ibaraki Prefecture (specific gravity: 2.54, FM = 3.
10) Fine sand: from Mandano, Ichihara-shi, Chiba (specific gravity: 2.62, FM
= 1.78) Coarse aggregate: from Tagawa, Aso-gun, Tochigi Prefecture (crushed stone 2005, specific gravity:
2.72) Unit quantity: Weight of each material when producing 1 m ³ of concrete

[0043]

[0044]

[Table 4]

[0045]

[Table 5]

[0046]

[Table 6]

From the results in Tables 5 and 6, it is clear that the cement dispersant of the present invention shows excellent slump loss prevention performance with almost no setting retardation. On the other hand, the naphthalenesulfonic acid formalin condensate of Comparative Example 7 has a very large slump loss. Further, the styrene maleic acid resin of Comparative Example 8 has remarkable setting retardation. Further, the dispersant of Comparative Example 9 also contains a carboxyl group and thus has a large setting retardation.

[0048]

The cement composition using the cement dispersant of the present invention has a large dispersibility between cement particles, a small change in the dispersibility with time, and no setting delay. The dispersant of the present invention can solve the problem of slump loss of the cement composition, and can produce high-quality concrete without prolonging the work time of cement construction because there is no setting delay.

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI C04B 24/26 C04B 24/26 Z // C04B 103: 40 (56) References JP-A-62-78137 (JP, A) JP-A-62 JP-A-119147 (JP, A) JP-A-6-206750 (JP, A) JP-A-6-191918 (JP, A) JP-B-59-18338 (JP, B1) JP-B-2-7898 (JP, B2) ) JP 2-7901 (JP, B2) JP 5-11057 (JP, B2) (58) Fields surveyed (Int. Cl. ⁷ , DB name) C04B 24/26 C04B 24:26 C04B 103: 40 C04B 103: 32

Claims (3)

(57) [Claims] 1. A water-soluble vinyl polymer containing a structural unit represented by the following general formula (I), a structural unit represented by the following general formula (II), and a structural unit represented by the following general formula (III): A unit represented by the general formula (I)
When the content ratio of the structural unit represented by the general formula (II) / the structural unit represented by the general formula (III) is 40 to 89/10 to 59/1
A cement dispersant characterized in that the amount is from 50 to 50% by weight. Embedded image [Where R ¹ and R ² represent hydrogen or a methyl group, M represents an alkali metal, an alkaline earth metal, an ammonium group or an organic amine group; (R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ each independently represent hydrogen or a methyl group.) [Chemical formula 3] [However, R ³ and R ⁴ are hydrogen or a methyl group, R ⁵ is an alkyl group having 1 to 3 carbon atoms, n is 2 or 3, and m is 1 to 3.
Y represents -CO-, and each independently represents an integer of 100. [Formula 4] [However, R ⁶ is hydrogen or a methyl group, R ⁷ is hydrogen, a methyl group or —CH ₂ COOM, K is hydrogen or —CO 2
OM are each independently represented, M is the same as above, and R
⁷ when the -CH ₂ COOM K is hydrogen. ] 2. A water-soluble vinyl polymer containing a structural unit represented by the following general formula (I), a structural unit represented by the following general formula (II), and a structural unit represented by the following general formula (III): A unit represented by the general formula (I)
When the content ratio of the structural unit represented by the general formula (II) / the structural unit represented by the general formula (III) is 40 to 89/10 to 59/1
A cement dispersant characterized in that the amount is from 50 to 50% by weight. Embedded image Wherein R ¹ and R ² represent hydrogen or a methyl group, M represents an alkali metal, an alkaline earth metal, an ammonium group, or an organic amine group; (R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ each independently represent hydrogen or a methyl group.) [Formula 7] Wherein R ³ and R ⁴ are hydrogen or a methyl group, R ⁵ is hydrogen, n is 2 or 3, m is an integer of 1 to 100, Y is —CH ₂ — or —CO—, each independently. To Embedded image [However, R ⁶ is hydrogen or a methyl group, R ⁷ is hydrogen, a methyl group or —CH ₂ COOM, K is hydrogen or —CO 2
OM are each independently represented, M is the same as above, and R
⁷ when the -CH ₂ COOM K is hydrogen. ] 3. A water-soluble vinyl polymer containing a structural unit represented by the following general formula (I), a structural unit represented by the following general formula (III), and a structural unit represented by the following general formula (IV): When the ratio of the structural unit represented by the formula (I) / the structural unit represented by the formula (IV) is 30/70 to 90/10 by weight, and the structural unit represented by the formula (III) is 50 % By weight, and the constituent unit represented by the formula (I) is 50% by weight or more. Embedded image Wherein R ¹ and R ² represent hydrogen or a methyl group, M represents an alkali metal, an alkaline earth metal, an ammonium group, or a salt of an organic amine; (R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ each independently represent hydrogen or a methyl group.) Embedded image [However, R ⁶ is hydrogen or a methyl group, R ⁷ is hydrogen, a methyl group or —CH ₂ COOM, K is hydrogen or —COOM
And M is the same as described above, and K is hydrogen when R ⁷ is —CH ₂ COOM. Embedded image Wherein R ⁸ and R ⁹ each independently represent hydrogen or a methyl group, and Z is [In the formula, A represents an alkylene group having 2 to 3 carbon atoms, l, m, and n represent a number of 1 to 100, and m + n represents a number of 2 to 100. ]