JPH10273351A - Dispersant for cement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copolymer useful as a cement dispersant having high water-reducing, slump loss-preventing and pore-holding properties in a small amount and not causing the retardation of coagulation by copolymerizing three kinds of monomers having specific chemical structures, respectively. SOLUTION: This dispersant for cement comprises a copolymer containing the following monomers A and B and/or C as essential constituent units. [A] is a monomer of formula I [Z<1> is hydrogen or -COO-[(C2 H4 O)/(C3 H6 O)n ]-H [R<1> is a 2-5C alkylene group; M<1> is hydrogen, a monovalent metal, ammonium group or an organic amine group; (m), (n) are each 0-200; (m)+(n)=0 to 400]. [B] is a monomer of formula II [Z<2> is hydrogen or -O-[(C2 H4 O)p /(C3 H6 O)q ]-SO3 M<2> ; R<2> is the same as R<1> ; M<2> is the same as M<1> ; (p), (q) are each 0-200; (p)+(q)=1 to 400]. [C] is a monomer of formula III [Z<3> is hydrogen atom or a group of formula IV; R<3> is the same as R<2> ; M<3> is the same as M<2> ; (r), (s) are the same as (p), (q), respectively].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement which, when added to a cement compound such as cement, mortar, concrete, etc., has a high water-reducing property, a high anti-slump loss property, a high air-bubble retention property and does not cause hardening delay. The present invention relates to a dispersant for use.

[0002]

2. Description of the Related Art Conventionally, naphthalenesulfonic acid formaldehyde condensate, ligninsulfonic acid salt, polycarboxylic acid compound and the like have been used as water reducing agents as additives for cement compounds such as concrete and mortar. In recent years, there has been an increasing demand for high strength concrete, and it has become necessary to reduce the amount of water in the concrete composition. Although the above water reducing agent has an effect of reducing the amount of water in the concrete composition, it has a drawback that a decrease in the fluidity (referred to as slump loss) of the concrete composition occurring with time cannot be avoided. . Thus, as a solution to this problem, a copolymer having a large water reduction and an excellent effect of preventing slump loss has been disclosed (JP-A-63-285140). However, when the copolymer is used, air entrainment is large, and it is necessary to use an antifoaming agent in combination, which causes problems such as separation over time. In addition, a method in which a terminal esterified product of a polyoxyalkylene block polymer having defoaming properties has been disclosed since excessively large air bubbles in a concrete molded product cause deterioration in appearance quality (Japanese Patent Application Laid-Open No. 61-111950). Gazette). However, even when this compound was used, the problems in appearance could be improved, but the effects of satisfying all of them were not obtained in air entrainment, water reduction, and slump loss prevention. Thus, there is disclosed a compound obtained by reacting a specific polyoxyalkylene derivative having a defoaming effect with a copolymer of a specific polyoxyalkylene derivative and maleic anhydride (Japanese Patent Application Laid-Open No. 7-157348). When this compound is used, the terminal of the polyoxyalkylene derivative is alkyl etherified, so that although the air entrainment is low, the hydrophilicity is reduced, and it is difficult to obtain sufficient water reduction. Then, in order to obtain a water reducing effect, it is considered that the amount of addition increases, causing a setting delay.

[0003]

SUMMARY OF THE INVENTION Under such circumstances, the present invention provides a high water-reducing property even with a small amount of addition, a high anti-slump loss property and a high bubble retention property at the same time. The purpose of the present invention is to provide a dispersant for cement that does not cause setting delay.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a dispersant for cement having the above-mentioned preferable performance, and as a result, a copolymer comprising a combination of monomers having a specific chemical structure has been obtained. , Shows high water reduction even with a small amount of addition,
In addition, they have found that they have high slump loss prevention and high bubble retention at the same time and do not cause coagulation delay, and have completed the present invention.

That is, the present invention provides a monomer (A) represented by the following general formula (1) and a monomer (B) represented by the following general formula (2) and / or a monomer represented by the following general formula (3): Is a dispersant for cement comprising a copolymer containing the monomer (C) as an essential constituent unit. General formula Z ¹ -R ¹ -COOM ¹ (1) ＺIn the formula, Z ¹ is a hydrogen atom or -COO-[(C ₂ H ₄ O) _m
/ A _{(C 3 H 6 O) n} ] -H. R ¹ represents an alkenylene group having 2 to 5 carbon atoms, and M ¹ represents hydrogen, a monovalent metal, an ammonium group or an organic amine salt. m is 0 to 200, n
Is an integer of 0 to 200, and m + n is an integer of 0 to 400. {General formula Z ² —R ² —O — [(C ₂ H ₄ O) _p / (C ₃ H ₆ O) _q ] —SO ₃ M ² (2) In the formula, Z ² represents a hydrogen atom or —O − [(C ₂ H ₄ O) _p / (C
₃ H ₆ O) _q] is a -SO ₃ M ^2. R ² represents an alkenylene group having 2 to 5 carbon atoms, and M ² represents hydrogen, a monovalent metal, an ammonium group or an organic amine salt. p is 0 to 200, q
Is an integer of 0 to 200, and p + q is an integer of 1 to 400. } General formula ^{Z 3 -R 3 -COO - [(} C 2 H 4 O) r / (C 3 H 6 O) s] -SO 3 M 3 (3) { wherein, Z ³ is a hydrogen atom or -COO -[(C ₂ H ₄ O) _{r
/ (C 3 H 6 O)} s] is -SO ₃ M ^3. R ³ has 2 to 5 carbon atoms
And M ³ represents a hydrogen atom, a monovalent metal, an ammonium group or an organic amine salt. r is 0
-200, s is an integer of 0-200, and r + s is an integer of 1-400. ｝

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The monomer (A) of the present invention is represented by the following general formula. Z ¹ -R ¹ -COOM ¹ (1) Z ¹ is a hydrogen atom or -COO-[(C ₂ H ₄ O) _m / (C ₃ H ₆
O) _n ] -H. M ¹ is a hydrogen atom, a monovalent metal (such as sodium or potassium), an ammonium group or an organic amine salt. R ¹ is an alkenylene group having 2 to 5 carbon atoms, and specific examples thereof include a —CH ＝ CH— group and a —CH ₂ CH =
CH- group, -CH = CHCH ₂ - group, -CH = C (CH ₃₎
— Group, —CH ₂ CH ＝ CHCH ₂ — group, —CH ₂ CH ＝ C
HCH ₂ CH ₂ — group, —CH ＝ CHCH ₂ CH ₂ CH ₂ —
_{Group, -CH = C (CH 3)} CH 2 CH 2 - , etc. group. Of these, preferred are a -CH = CH- group, -C
An H = CHCH ₂ — group, a —CH ＝ C (CH ₃ ) — group, and more preferred are a —CH ＝ CH— group and a —CH ＝ C (CH ₃ ) — group. m is usually 0 to 200, preferably 0 to 100,
N is an integer of usually 0 to 200, preferably 0 to 100, and more preferably 0 to 50. m + n is from 0 to 400, preferably from 0 to 10
0, more preferably 0 to 50. [(C ₂ H ₄ O) _m /
In (C ₃ H ₆ O) _n ], when both m and n are 1 or more, random addition or block addition may be used, but block addition is preferred. In the case of block shape, (C ₂ H ₄
The order of O) _m and (C ₃ H ₆ O) _n does not matter. [(C ₂ H ₄ O) _m /
The ratio of m / n in (C ₃ H ₆ O) _n ] is usually 10/0 to 0/1.
0, preferably 9/1 to 5/5.

Specific examples of the monomer (A) include acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, mesaconic acid, fumaric acid, citraconic acid, maleic anhydride, itaconic anhydride, and itaconic anhydride. Mesaconic acid; half-alkylene oxide ester of maleic acid (block-shaped adduct of 20 mol of ethylene oxide and 10 mol of propylene oxide), half-alkylene oxide ester of itaconic acid (block-shaped addition of 20 mol of ethylene oxide and 10 mol of propylene oxide) Product), a half-alkylene oxide esterified product of mesaconic acid (a block-shaped adduct of 20 moles of ethylene oxide and 10 moles of propylene oxide), a half-alkylene oxide esterified product of fumaric acid (20 moles of ethylene oxide and propylene oxide 1) Blocky adduct of mol), semi-alkylene oxide ester (ethylene oxide 20 moles of propylene oxide 10-mole blocky adduct of citraconic acid). Preferred among these are acrylic acid, methacrylic acid, maleic acid, and maleic acid half-alkylene oxide esters.

The monomer (B) of the present invention is represented by the following general formula. ^{Z 2 -R 2 -O - [(} C 2 H 4 O) p / (C 3 H 6 O) q] -SO 3 M 2 (2) Z 2 is a hydrogen atom or -O - [(C ₂ H ₄ O) _p / (C ₃ H
₆ O) _q ] -SO ₃ M ² . R ² is an alkenyl group having 2 to 5 carbon atoms, and specific examples thereof include a —CH ＝ CH— group,
CH ₂ CH = CH- group, -CH = CHCH ₂ - group, -CH
＝ C (CH ₃ ) —, —CH ＝ C (CH ₃ ) —CH ₂ —,
CH ₂ CH = CHCH ₂ - group, -CH ₂ CH = CHCH ₂ C
H ₂ — group, —CH ＝ CHCH ₂ CH ₂ CH ₂ — group, —CH ＝
And C (CH ₃ ) CH ₂ CH ₂ — groups. Of these, preferred are -CH = CH- groups, -CH = CHCH
₂ - _{group, -CH = C (CH 3)} - group, -CH ₂ CH = CHC
H ₂ — groups, more preferably —CH ＝ CH— groups, —C
H = C (CH ₃ ) — group. M ² is M ¹ of the monomer (A)
Is the same as p is usually 0 to 200, preferably 1 to 1
00, more preferably 5 to 50; q is usually 0 to 20
0, preferably 1 to 100, more preferably 1 to 50
Is an integer. p + q is 1 to 400, preferably 1 to 100, and more preferably 5 to 50. [(C ₂
[H ₄ O) _p / (C ₃ H ₆ O) _q ], where p and q are both 1 or more, the addition may be random or block addition, but preferably block addition. In block form
The order of (C ₂ H ₄ O) _p and (C ₃ H ₆ O) _q does not matter. [(C ₂ H ₄
O) _p / (C ₃ H ₆ O) _q ], the ratio of p / q is usually from 10/0 to
0/10, preferably 9/1 to 5/5.

Specific examples of the monomer (B) include a sulfated oxide of a block-like adduct of 20 mol of allyl alcohol ethylene oxide and 10 mol of propylene oxide;
Sulfuric oxide of block-like adduct of 20 moles of ethylene oxide of methallyl alcohol and 10 moles of propylene oxide, ethylene oxide 20 of crotyl alcohol
Sulfuric oxide of a block-shaped adduct of 10 mol of propylene oxide and 20 mol of ethylene oxide of 10-mol of 2-butene-1,4-diol and 10 mol of propylene oxide. Of these, preferred are sulfated oxides of block adducts of ethylene oxide and propylene oxide of allyl alcohol, and sulfated oxides of block adducts of ethylene oxide and propylene oxide of methallyl alcohol, and more preferred are allyl alcohols. It is a sulfated oxide of a block-like adduct of ethylene oxide and propylene oxide of alcohol.

The monomer (C) of the present invention is represented by the following general formula. ^{Z 3 -R 3 -COO - [(} C 2 H 4 O) r / (C 3 H 6 O) s] -SO 3 M 3 (3) Z 3 is a hydrogen _{atom, -COO - [(C 2 H} 4 O) _r / (C ₃ H
^{_{6 O) s] -SO 3 M}} 3, or -COOM ^3. M ³ are the same as M ¹ of the monomer (A). R ³ is an alkenyl group having 2 to 5 carbon atoms, and specific examples thereof include —CH ＝ CH—
Group, -CH ₂ CH = CH- group, -CH = CHCH ₂ - group,
—CH ＝ C (CH ₃ ) —, —CH ₂ CH ＝ CHCH ₂ —
_{Group, -CH 2 CH = CHCH 2 CH} 2 - group, -CH = CH
CH ₂ CH ₂ CH ₂ — group, —CH ＝ C (CH ₃ ) CH ₂ CH ₂ —
And the like. Of these, preferred is -CH
ＣＨCH- group and -CH ＝ C (CH ₃ )-group. r is usually 0 to 200, preferably 1 to 100, more preferably 5 to 50; s is usually 0 to 200, preferably 1 to 10
0, more preferably an integer of 1 to 50. r + s is 1 to 400, preferably 1 to 100, and more preferably 5 to 50. [(C ₂ H ₄ O) _r / (C ₃ H ₆ O) _s ]
When both r and s are 1 or more, random addition or block addition may be used, but block addition is preferred. In block form, (C ₂ H ₄ O) _r and (C ₃ H ₆ O) _s
In any order. _{R in} [(C ₂ H ₄ O) _r / (C ₃ H ₆ O) _s ]
The ratio of / s is usually from 10/0 to 0/10, preferably from 9/1 to 5/5.

Specific examples of the monomer (C) include a sulfated oxide of a block-shaped adduct of 20 mol of ethylene oxide of acrylic acid and 10 mol of propylene oxide, and 20 mol of ethylene oxide of methacrylic acid and 10 mol of propylene oxide. Sulfur oxide of block-form adduct, sulfate of block-form adduct of 20 moles of ethylene oxide of crotonic acid and 10 moles of propylene oxide; diester of maleic acid (block-form adduct of 10 moles of ethylene oxide and 5 moles of propylene oxide) Sulfates,
Sulfated diester of mesaconic acid (block adduct of 10 mol of ethylene oxide and 5 mol of propylene oxide), sulfated diester of fumaric acid (blocked adduct of 10 mol of ethylene oxide and 5 mol of propylene oxide), Sulfuric oxide of a diester of citraconic acid (a block-shaped adduct of 10 mol of ethylene oxide and 5 mol of propylene oxide) and the like. Among these, preferred are a sulfated oxide of a block-shaped adduct of ethylene oxide and propylene oxide of acrylic acid, and a sulfated oxide of a block-shaped adduct of ethylene oxide and propylene oxide of methacrylic acid.

[0012] In addition to the above-mentioned essential component monomers, the copolymer of the present invention may further comprise, within a range that does not impair the performance of the present invention.
Other unsaturated monomers can be copolymerized. Specific examples of such a copolymerizable monomer include a block-shaped adduct of 20 mol of allyl alcohol ethylene oxide and 10 mol of propylene oxide, and 20 mol of ethylene oxide of methallyl alcohol and 10 mol of propylene oxide. Block adducts, block adducts of 20 moles of ethylene oxide of crotyl alcohol and 10 moles of propylene oxide; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate; vinyl aromatic compounds such as styrene and indene; isobutylene; Olefins such as isoprene; allyl alcohol, methallyl alcohol, crotyl alcohol, 3-butenyl alcohol,
Alkenyl alcohols such as -pentenyl alcohol, 3-methyl-3-butenyl alcohol; acrylamide;
Alkenyl alcohol sulfate ethers and the like. In this case, the amount of the other unsaturated monomer is usually from 0 to 70 mol%, preferably from 0 to 50 mol%, in the structural units of the copolymer.

The monomers (A), (B) and (C) are not limited to one kind each, and two or more kinds of monomers may be used in combination. In the copolymer, the content ratio of the constitutional unit represented by monomer (A) / {monomer (B) or / and monomer (C)} is 98/2 to 20 / 80, and particularly preferably 95/5 to 40/60. The weight average molecular weight of the copolymer is usually from 1,000 to 500,000, preferably from 1,500 to 100,000.

The method for producing the copolymer 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 as a reaction type, and water or alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; ketones; carbonization such as benzene, xylene, toluene, n-hexane, and cyclohexane as a solvent. Hydrogens and the like. Benzoyl peroxide as a polymerization initiator,
Peroxides such as hydrogen peroxide; azo compounds represented by azobisisobutyronitrile; persulfates and the like can be used. The reaction temperature depends on the solvent and the polymerization initiator,
Usually, it can be carried out at 50 ° C to 200 ° C. Also, the method for introducing a sulfate group is not limited in the present invention, and any conventionally known method can be applied. For example, the reaction can be performed by mixing a raw material having an alcohol component and sulfamic acid and stirring the mixture at 90 ° C. to 150 ° C. for about 8 hours in a nitrogen atmosphere. The introduction of the sulfate group may be performed on the monomer before polymerization or after the copolymerization.

The dispersant for cement of the present invention is usually used in an amount of 0.00 to cement in view of high bubble retention, high water reduction, high slump loss prevention, setting delay and workability.
It is added at a ratio of 1 to 3% by weight, preferably 0.04 to 1% by weight. The dispersant for cement of the present invention is a dispersant of naphthalenesulfonic acid formalin condensate, another dispersant such as a polycarboxylic acid compound or an antifoaming agent, a swelling agent, a rust inhibitor, a setting accelerator, as long as its performance is not impaired. It may be used in combination with additives having various functions, such as a setting retarder and an air entrainer.

[0016]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Parts are parts by weight. Example 1 300 parts of alkylene oxide adduct of allyl alcohol (ethylene oxide 20 mol, propylene oxide 10 mol block adduct), sulfamic acid
5 parts were charged into a glass reaction vessel equipped with a stirrer, a nitrogen inlet tube, a thermometer, a reflux tube, and a dropping funnel.
The temperature was raised to 95 ° C., and the mixture was stirred for about 8 hours. The amount of bound sulfuric acid was measured to confirm the completion of the reaction (synthesis of monomer c). To this, 30 parts of water was added to dissolve uniformly, and heated to 80 ° C. while replacing the atmosphere with nitrogen. Here, 0.5 part of ammonium persulfate diluted with 10 parts of water and 73.5 parts of maleic acid were added.
A part thereof dissolved in 100 parts of water was simultaneously added dropwise over 4 hours to start polymerization, and the reaction was completed at 4 hours while maintaining the reaction temperature at 80 ° C. to obtain a desired dispersant 1. Examples 2 to 10 and Comparative Examples 1 to 3 Dispersants 2 to 10 were obtained in the same manner as in Example 1 except that the monomers were changed as shown in Table 1. In addition, the numerical value in Table 1 shows mol%. {} Indicates random addition, and the other indicates block addition.

[0017]

[Table 1] a: maleic acid b: acrylic acid c: CH ₂ ＣＨCHCH ₂ O (C ₂ H ₄ O) ₂₀ (C ₃ H ₆ O) ₁₀ SO ₃ NH ₄ d: CH ₂ ＣC (CH ₃ ) CH ₂ O ( _{C 2 H 4 O) 20 (} C 3 H 6 O) 10 SO 3 NH 4 e: CH 2 = C (CH 3) -COO {(C 2 H 4 O) 20 (C 3 H 6 O) 10} SO _{3 NH 4 f: CH 2 =} CH-COO {(C 2 H 4 O) 20 (C 3 H 6 O) 10} SO 3 NH 4 g: CH 2 = CHCH 2 O (C 2 H 4 O) 20 ( _{C 3 H 6 O) 10 H} h: CH 2 = C (CH 3) CH 2 O (C 2 H 4 O) 20 (C 3 H 6 O) 10 H i: methyl methacrylate j: allyl alcohol

Test Examples 1 to 10 Using the dispersants 1 to 10 of the present invention obtained in Examples 1 to 10 and the copolymers of Comparative Examples 1 to 3 as concrete dispersants for cement, Raw materials were created. The materials of the concrete raw materials are shown below, and the mixing ratios are shown in Table 2. The composition and test conditions are shown below.

Cement: ordinary Portland cement (manufactured by Nippon Cement Co., Ltd.) Fine aggregate: Aichigawa, specific gravity 2.65, coarse particle ratio 2.96 Coarse aggregate: Aichigawa, specific gravity 2.70, coarse particle ratio 6 .77

[0020]

[Table 2] * 1) Water content per 100 parts of cement * 2) Volume ratio of fine aggregate in total aggregate (fine aggregate + coarse aggregate)

Then, the above-mentioned cement additives and the concrete raw materials were kneaded, and the mixing was calculated so that the mixing amount became 50 liters. All the materials were put into a forced kneading mixer. Then, the mixture was immediately mixed for 2 minutes (19 rpm), and the whole amount was discharged from the mixer, and the slump and the air amount were measured.
This value is the value immediately after kneading. Then, return the entire amount of concrete to the tilting mixer, and rotate at low speed (4 to 5 rpm).
At a predetermined time (30 minutes and 60 minutes) to perform a slump measurement test. Table 3 shows the results. The setting time of the product obtained from this concrete raw material was measured, and the results are shown in Table 4.

The slump, the setting time and the amount of air were measured and tested according to the following methods.

Slump: According to JIS A1101. Setting time: according to ASTM C403-79T. Air volume: According to JIS A1128.

[0024]

[Table 3]

[0025]

[Table 4]

From the results shown in Tables 3 and 4, all of the dispersants of the present invention exhibited excellent effects in terms of high water reduction, prevention of slump loss, and bubble stability even with an addition amount of less than half as compared with Comparative Examples. You can see that it works.

[0027]

When the dispersant for cement of the present invention is added to a cement compound such as cement, mortar or concrete, it is added in a smaller amount than before.
High water-reduction is obtained, and at the same time, it has high anti-slump loss property and high air bubble retention property, and does not cause setting delay.

Claims (2)

[Claims] 1. A monomer (A) represented by the following general formula (1) and a monomer (B) represented by the following general formula (2)
And / or a monomer (C) represented by the following general formula (3)
A dispersant for cement comprising a copolymer having as an essential constituent unit. General formula Z ¹ -R ¹ -COOM ¹ (1) ＺIn the formula, Z ¹ is a hydrogen atom or -COO-[(C ₂ H ₄ O) _m
/ A _{(C 3 H 6 O) n} ] -H. R ¹ represents an alkenylene group having 2 to 5 carbon atoms, and M ¹ represents hydrogen, a monovalent metal, an ammonium group or an organic amine salt. m is 0 to 200, n
Is an integer of 0 to 200, and m + n is an integer of 0 to 400. {General formula Z ² —R ² —O — [(C ₂ H ₄ O) _p / (C ₃ H ₆ O) _q ] —SO ₃ M ² (2) In the formula, Z ² represents a hydrogen atom or —O − [(C ₂ H ₄ O) _p / (C
₃ H ₆ O) _q] is a -SO ₃ M ^2. R ² represents an alkenylene group having 2 to 5 carbon atoms, and M ² represents hydrogen, a monovalent metal, an ammonium group or an organic amine salt. p is 0 to 200, q
Is an integer of 0 to 200, and p + q is an integer of 1 to 400. } General formula ^{Z 3 -R 3 -COO - [(} C 2 H 4 O) r / (C 3 H 6 O) s] -SO 3 M 3 (3) { wherein, Z ³ is a hydrogen atom or -COO -[(C ₂ H ₄ O) _{r
/ (C 3 H 6 O)} s] is -SO ₃ M ^3. R ³ has 2 to 5 carbon atoms
And M ³ represents a hydrogen atom, a monovalent metal, an ammonium group or an organic amine salt. r is 0
-200, s is an integer of 0-200, and r + s is an integer of 1-400. ｝ 2. The monomer (A) in the structural unit in the copolymer is 20 to 98 mol%, and the total of the monomer (B) and the monomer (C) is 2 to 80 mol%. The cement dispersant according to claim 1, wherein