JPH07247150A - Concrete admixture - Google Patents

Abstract

PURPOSE:To improve fluidity, fluidity-retaining property and foam-retaining property of a hydraulic composition by including a specific copolymer as an essential component. CONSTITUTION:10-99wt.% of total amount f 5-95wt.% of formula I (R1 is H or methyl; (m1) is 0-2; (n1) is 110-300; X is H or a 1-3C alkyl; A0 is a 2-3C oxyalkylene) and 5-95wt.% of a monomer of formula II [R2 is R1; m2 is (m1); (n2) is 1-30] is copolymerized with 90-1wt.% of a monomer formula II and/or formula IV [R6 is R1; R3 to R5 each is H, methyl or (CH2)m3COOM3; Y is SO3M3 or formula V; M1 to M4 each is H, alkali (alkaline earth) metal, ammonium or a (substituted) amino] to provide the objective concrete admixture consisting of a copolymer having 1000-50000 weight-average molecular weight (measured by gel permeation chromatography/sodium polystyrene-sulfonate/water system). This admixture is blended with 5-50wt.% of well-known cement admixture such as formaldehyde condensate of naphthalenesulfonic acid salt.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a concrete admixture. More specifically, the present invention relates to a concrete admixture exhibiting excellent effects on fluidity, fluidity retention and air bubble retention of hydraulic compositions such as cement paste, mortar and concrete.

[0002]

BACKGROUND OF THE INVENTION Among concrete admixtures, naphthalene sulfonic acid formaldehyde condensate (hereinafter referred to as naphthalene type) and melamine sulfonic acid formaldehyde condensate are typical ones having a great fluidizing effect. (Hereinafter, referred to as melamine-based), polycarboxylic acid salts (hereinafter referred to as polycarboxylic acid-based), and so on, which are called high performance water reducing agents.

While these admixtures each have excellent characteristics, they have problems. For example, although naphthalene type and melamine type have excellent curing characteristics, they have problems in fluidity retention (referred to as slump loss) and bubble amount retention, and polycarboxylic acid type has a problem that curing delay is large.

In recent years, with the development of a polycarboxylic acid system exhibiting excellent fluidity, it becomes possible to obtain dispersibility with a low addition amount, and curing delay is being improved. For example, copolymers of a polyalkylene glycol monoester monomer having an unsaturated bond and an acrylic acid and / or an unsaturated dicarboxylic acid monomer (Japanese Patent Publication No. 59-18338, Japanese Patent Publication No. 2-78).
No. 978, No. 2-7898, No. 2-7901, No. 2-11
542, JP-A-3-75252, JP-A-59-162163) and the like.

However, even in the polycarboxylic acid system having these alkylene chains, the entrainment of air bubbles is high, and the fluctuation due to the increase in the air amount during the period from the concrete production to the transportation is extremely large. The current situation is that it is difficult to control about 4% by using an entraining agent together. These problems are dealt with by blending an antifoaming agent, etc., but the amount of air changes drastically due to mixing conditions, agitator conditions of mixer trucks, and transport time. However, the admixture itself has been desired to be improved.

More specifically, it has been speculated that the excellent dispersion mechanism of a water-soluble vinyl copolymer having an oxyalkylene group is a dispersion mechanism which suppresses the adhesion of particles because the graft structure of the oxyalkylene chain serves as a steric barrier. . This oxyalkylene chain is very effective for improving dispersibility, but the foaming property increases with time, and the above-mentioned problems are presently present.

[0007]

Means for Solving the Problems The present inventors have paid attention to the alkylene glycol chain of a polyalkylene glycol monoester type monomer and studied the relationship between the length of the alkylene glycol chain and the foaming property and bubble stability. . As a result, the foaming property is extremely reduced by making the alkylene glycol chain a long chain of 110 mol or more and the foam breaking property is exhibited, and the foaming property is obtained when the alkylene glycol chain is a short chain of 30 mol or less. Was found to be large and increased over time.

Based on these results, the present inventors diligently studied the length of the alkylene glycol chain, and by combining and copolymerizing long-chain and short-chain polyalkylene glycol monoester monomers, We have completed an improved water-soluble vinyl copolymer that exhibits extremely excellent foamability and bubble stability and exhibits high fluidity with a low amount added.

That is, the present invention provides a monomer (A) represented by the following general formula (a) and a monomer (B) represented by the following general formula (b):
And a concrete admixture containing as an essential component a copolymer obtained by polymerizing a monomer (C) represented by the following general formula (c) and / or general formula (d).

[0010]

[Chemical 2]

The present invention is excellent in fluidity, fluidity retention, foaming ability, and bubble stability due to the above-mentioned constitution.

As in the present invention, the monomer (A) and the monomer (B) are used as a starting material and copolymerized to give a distribution of alkylene glycol chains excellent in foaming property and bubble stability.
The desired performance cannot be obtained with an average alkylene glycol chain distribution of long chains and short chains.

In the present invention, the monomer (A) represented by the general formula (a) is methoxy polyethylene glycol,
Methoxy polypropylene glycol, methoxy polyethylene polypropylene glycol, ethoxy polyethylene glycol, ethoxy polypropylene glycol, ethoxy polyethylene polypropylene glycol, propoxy polyethylene glycol, propoxy polypropylene glycol, propoxy polyethylene polypropylene glycol, etc. Dehydrogenation (oxidation) of fatty acids
An esterification product with a reaction product or an ethylene oxide or propylene oxide addition product to a dehydrogenation (oxidation) reaction product of (meth) acrylic acid or a fatty acid is used. The number of added moles of polyalkylene glycol is 110-300, but 1
About 20 to 200 mol is preferable for dispersibility. Both the ethylene oxide and propylene oxide adducts can be used in any of random addition, block addition, alternating addition, and the like. When the number of moles of polyalkylene glycol added exceeds 300, not only the polymerizability decreases but also the dispersibility decreases.

Further, if it is less than 110 mol, the foaming entrainment is high and the foam breaking property is lost, and the desired performance cannot be obtained when the monomer (B) is used in combination for copolymerization, resulting in increased bubbles. Therefore, safety becomes a problem.

In the present invention, the monomer (B) represented by the general formula (b) includes methoxy polyethylene glycol, methoxy polypropylene glycol, methoxy polyethylene polypropylene glycol, ethoxy polyethylene glycol, ethoxy polypropylene glycol, ethoxy polyethylene polypropylene glycol, One-terminal alkyl-blocked polyalkylene glycol such as propoxy polyethylene glycol, propoxy polypropylene glycol, and propoxy polyethylene polypropylene glycol, and the esterification product of (meth) acrylic acid or fatty acid dehydrogenation (oxidation) reaction product or (meth) acrylic acid or fatty acid An ethylene oxide or propylene oxide adduct to the dehydrogenation (oxidation) reaction product is used. The number of addition moles of polyalkylene glycol is 1 to 30, but if the number of addition moles of polyalkylene glycol exceeds 30, the monomer
Even if the copolymer is used together with (A), the desired foaming property and bubble stability cannot be obtained. In consideration of dispersibility, the number of moles of polyalkylene glycol added is preferably about 3 to 30.

Examples of the compound represented by the general formula (c) include acrylic acid, methacrylic acid, crotonic acid and their metal salts. Further, as the unsaturated dicarboxylic acid-based monomer, maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, fumaric acid, or their alkali metal salts, alkaline earth metal salts, Ammonium salts, amine salts and the like are used.

As the compound represented by the general formula (d), allyl sulfonic acid, methallyl sulfonic acid or their alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts and the like are used.

A monomer (A) constituting the copolymer of the present invention,
The reaction unit of monomer (B) is monomer (A) / monomer (B) = 5 / 95〜
The range of 95/5 (% by weight) is suitable, and more preferably,
The range of monomer (A) / monomer (B) = 10/90 to 30/70 (wt%) is preferable.

The reaction units of the monomer (A) and the monomer (B) and the monomer (C) which constitute the copolymer of the present invention are the monomer (A) and the monomer (B) / The range of monomer (C) = 10/90 to 99/1 (% by weight) is suitable for dispersibility and bubble stability, and more preferably monomer (A) and monomer (B) / monomer The range of monomer (C) = 30/70 to 95/5 (% by weight) is preferable.

The copolymer of the present invention may be copolymerized with other copolymerizable monomers within the range that does not impair the effects of the present invention. For example, acrylonitrile, acrylic acid ester, acrylamide, methacrylamide,
Examples thereof include styrene and styrene sulfonic acid.

The weight average molecular weight (gel permeation chromatography method / polystyrene sulfonic acid conversion) of the copolymer of the present invention is preferably in the range of 1,000 to 500,000,
The range of 5,000 to 100,000 is more preferable for dispersibility.

If the weight average molecular weight is less than 1,000, the dispersibility is insufficient, and if it exceeds 500,000, the cohesiveness is exhibited, which is not preferable.

Further, the concrete admixture of the present invention can be used in combination with a known cement admixture. Examples of known cement admixtures include naphthalene sulfonate formaldehyde condensate, melamine sulfonate formaldehyde condensate, lignin sulfonate, phenol / sulfanilate formaldehyde condensate, and oxycarboxylate. The ratio of combined use is preferably 5 to 50% by weight in the concrete admixture.

The polymer of the present invention can be produced by a known method. For example, JP-A-59-162163,
Methods such as Japanese Patent Publication No. 2-11542, Japanese Patent Publication No. 2-7901 and Japanese Patent Publication No. 2-7897 can be mentioned.

The solvent used for the solution polymerization is water,
Methyl alcohol, ethyl alcohol, isopropyl alcohol, benzene, toluene, xylene, cyclohexane, n-hexane, aliphatic hydrocarbons, ethyl acetate, acetone, methyl ethyl ketone and the like can be mentioned. From the viewpoint of handling and reaction equipment, water and alcohol having 1 to 4 carbon atoms are preferable.

As the water-based polymerization initiator, a water-soluble initiator such as ammonium or alkali metal persulfate or hydrogen peroxide is used. Benzoyl peroxide, lauroyl peroxide and the like are used as a polymerization initiator for solution polymerization other than the aqueous system.

It is also possible to use sodium sulfite, mercaptoethanol or an amine compound as a chain transfer agent in combination with the polymerization initiator, and these polymerization initiators or chain transfer agents can be appropriately selected and used. it can.

Further, the amount of the concrete admixture of the present invention added to concrete is 0.02 to the cement as solid content.
1.0% by weight is preferable, and 0.05 to 0.5% by weight is more preferable.

The concrete admixture of the present invention can be used in combination with known additives (materials). For example, AE agent,
AE water reducing agent, superplasticizer, high performance water reducing agent, retarder, early strengthening agent,
Examples include accelerators, foaming agents, foaming agents, defoaming agents, thickeners, waterproofing agents, antifoaming agents, silica sand, blast furnace slag, fly ash, and silica fume.

Further, the concrete admixture of the present invention is added to cement paste, mortar, concrete, etc. having a composition of hydraulic cement, and its contents are not limited.

[0031]

EXAMPLES The present invention will be specifically described below, but the present invention is not limited to these examples. The parts and% in the following examples are parts by weight and% by weight.

The contents of the monomer (A) and the monomer (B) used in the polymerization of the present invention and the copolymerization constituent ratio of the monomer (A) and the monomer (B) are shown below. Contents of Monomer (A) and Monomer (B) A-1: Polyethylene glycol monoacrylate (number of moles of ethylene oxide added = 118) A-2: Polyethylene glycol monomethacrylate
(Ethylene oxide addition mole number = 150) A-3: Polyethylene polypropylene glycol monomethacrylate (block addition product of ethylene oxide addition mole number = 265, propylene oxide addition mole number = 5) A-4 (comparison): polyethylene glycol monomethacrylate (ethylene oxide Addition mole number = 350) B-1: Polyethylene glycol monoacrylate (Ethylene oxide addition mole number = 3) B-2: Polyethylene glycol monomethacrylate
(Ethylene oxide addition mole number = 9) B-3: Polyethylene polypropylene glycol monomethacrylate (block addition product of ethylene oxide addition mole number = 23, propylene oxide addition mole number = 3) B-4 (comparison): polyethylene glycol monomethacrylate (ethylene oxide Addition mol number = 85) Copolymerization ratio of monomer (A) / monomer (B) Constitution-1: A-1 / B-1 (wt%) = 10/90 Constitution-2: A-1 / B-2 (% by weight) = 20/80 Configuration-3: A-2 / B-3 (% by weight) = 30/70 Configuration-4: A-3 / B-2 (% by weight) = 3/97 Structure-5: A-4 Structure-6: A-4 / B-2 (wt%) = 30/70 Structure-7: B-4 Structure-8: A-1 / B-4 (wt%) = 10 / 90.

Structure-1 to Structure-8 showing the copolymer of monomer (A) and monomer (B) and monomer (C) or monomer
An example of producing a copolymer with (C) and a copolymerizable monomer is shown below. Production Example 1 150 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. Composition-1 36g and acrylic acid 68g
The above mixture, 0.01 mol of a 20% ammonium persulfate aqueous solution, and 5 g of 2-mercaptoethanol were simultaneously added dropwise to the reaction system over 2 hours, and the same temperature (75
Aging). After aging, the temperature is raised to 95 ° C., 15 g of 36% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After completion of the aging, 0.7 mol of 48% sodium hydroxide was added to acrylic acid for neutralization to obtain a copolymer having a molecular weight of 25,000.

Production Example 2 300 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. Composition-1 144 g and methacrylic acid
A mixture of 67 g and 20% ammonium persulfate aqueous solution.
02 mol and 2 g of 2-mercaptoethanol were simultaneously added dropwise to the reaction system over 2 hours, and the temperature was kept at the same temperature for 1 hour.
Aging at (75 ℃). After aging, the temperature was raised to 95 ° C, 10 g of 36% hydrogen peroxide was added dropwise over 1 hour, and the temperature (95%) was maintained for 2 hours.
Aging). After aging, neutralize by adding 0.7 mol of 48% sodium hydroxide to methacrylic acid, molecular weight 32,0
A copolymer of 00 was obtained.

Production Example 3 370 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. A mixture of 215 g of composition-1 and 71 g of monosodium maleate and 20 g of sodium allylsulfonate, 0.01 mol of a 20% ammonium persulfate aqueous solution and 3 g of 2-mercaptoethanol were simultaneously added dropwise to the reaction system over 2 hours. Same temperature for 1 hour (75
Aging). After aging, the temperature is raised to 95 ° C., 15 g of 36% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After aging, add 10% sodium hydroxide
The copolymer was neutralized to pH 7 and a copolymer having a molecular weight of 38,000 was obtained.

Production Example 4 300 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. Composition-2 145 g and methacrylic acid
A mixture of 76 g and 20% ammonium persulfate aqueous solution.
02 mol and 3 g of 2-mercaptoethanol were dropped into the reaction system simultaneously over 2 hours, and the same temperature was applied for 1 hour.
Aging at (75 ℃). After aging, the temperature was raised to 95 ° C, 10 g of 36% hydrogen peroxide was added dropwise over 1 hour, and the temperature (95%) was maintained for 2 hours.
Aging). After aging, neutralize by adding 0.7 mol of 48% sodium hydroxide to methacrylic acid, molecular weight 45,0
A copolymer of 00 was obtained.

Production Example 5 400 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. Composition-3 276g and acrylic acid 57
g, a mixture of 20 g of sodium methallyl sulfonate, 0.02 mol of a 20% ammonium persulfate aqueous solution and 3 g of 2-mercaptoethanol were simultaneously added dropwise to the reaction system over 2 hours, and the same temperature (75 ° C) for 1 hour. Mature in. After aging, the temperature is raised to 95 ° C., 10 g of 36% hydrogen peroxide is added dropwise over 1 hour, and aging is performed at the same temperature (95 ° C.) for 2 hours. After aging, add 48% sodium hydroxide to acrylic acid.
0.7 mol was added and neutralized to obtain a copolymer having a molecular weight of 57,000.

Production Example 6 A reaction vessel equipped with a stirrer was charged with 1000 g of water, and the temperature was raised to 75 ° C. in a nitrogen atmosphere. A mixture of 624 g of composition-4 and 95 g of sodium methallyl sulfonate, 0.02 mol of 20% ammonium persulfate aqueous solution and 3 g of 2-mercaptoethanol were simultaneously added dropwise to the reaction system over 2 hours, and the same temperature was maintained for 1 hour. Aging at (75 ℃). After aging, the temperature was raised to 95 ° C, and 10 g of 36% hydrogen peroxide was added dropwise over 1 hour.
Aging at the same temperature (95 ℃) for a certain period of time. After completion of the aging, 10% sodium hydroxide was added to neutralize to pH 7 to obtain a copolymer having a molecular weight of 98,000.

Production Example 7 400 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. Composition-3 276g and acrylic acid 57
g, a mixture of 76 g of sodium methallyl sulfonate and 10 g of sodium styrene sulfonate, 0.02 mol of 20% ammonium persulfate aqueous solution and 3 g of 2-mercaptoethanol were simultaneously added dropwise to the reaction system over 2 hours and then 1 hour. Aging at the same temperature (75 ℃). After aging, the temperature was raised to 95 ° C, and 10 g of 36% hydrogen peroxide was added dropwise over 1 hour.
Aging at the same temperature (95 ℃) for a certain period of time. After completion of the aging, 0.7 mol of 48% sodium hydroxide was added to acrylic acid for neutralization to obtain a copolymer having a molecular weight of 57,000.

Comparative Production Example 8 250 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. 154g of composition-5 and methacrylic acid
A mixture of 76 g and 20% ammonium persulfate aqueous solution.
01 mol and 7 g of 2-mercaptoethanol were dropped into the reaction system at the same time over 2 hours at the same temperature for 1 hour.
Aging at (75 ℃). After aging, the temperature was raised to 95 ° C, 21 g of 36% hydrogen peroxide was added dropwise over 1 hour, and the temperature (95%) was maintained for 2 hours.
Aging). After aging, neutralize by adding 0.7 mol of 48% sodium hydroxide to methacrylic acid,
5,000 copolymers were obtained.

Comparative Production Example 9 600 g of water was charged into a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. Composition-6 495g and acrylic acid 65
g mixture and 20% ammonium persulfate aqueous solution 0.01
Molar and 2-mercaptoethanol (5 g) were simultaneously dropped into the reaction system over 2 hours, and the same temperature was applied for 1 hour.
Aging at (75 ℃). After aging, the temperature was raised to 95 ° C, 15 g of 36% hydrogen peroxide was added dropwise over 1 hour, and the temperature (95%) was maintained for 2 hours.
Aging). After aging, neutralize by adding 0.7 mol of 48% sodium hydroxide to acrylic acid, molecular weight 65,000
A copolymer of

Comparative Production Example 10 450 g of water was charged in a reaction vessel equipped with a stirrer and heated to 75 ° C. in a nitrogen atmosphere. Composition-7 286g and acrylic acid 65
g mixture and 20% ammonium persulfate aqueous solution 0.01
Molar and 2-mercaptoethanol (5 g) were simultaneously dropped into the reaction system over 2 hours, and the same temperature was applied for 1 hour.
Aging at (75 ℃). After aging, the temperature was raised to 95 ° C, 15 g of 36% hydrogen peroxide was added dropwise over 1 hour, and the temperature (95%) was maintained for 2 hours.
Aging). After aging, neutralize by adding 0.7 mol of 48% sodium hydroxide to acrylic acid, molecular weight 32,000
A copolymer of

Comparative Production Example 11 In a reaction vessel equipped with a stirrer, 250 g of water was charged and heated to 75 ° C. in a nitrogen atmosphere. Composition-8 46g and acrylic acid
A mixture of 65 g and a 20% ammonium persulfate aqueous solution.
01 mol and 6 g of 2-mercaptoethanol were dropped into the reaction system at the same time over 2 hours at the same temperature for 1 hour.
Aging at (75 ℃). After aging, the temperature was raised to 95 ° C, 16 g of 36% hydrogen peroxide was added dropwise over 1 hour, and the temperature (95%) was maintained for 2 hours.
Aging). After aging, neutralize by adding 0.7 mol of 48% sodium hydroxide to acrylic acid, molecular weight 97,000
A copolymer of

The contents and symbols of the dispersants used in the examples other than the comparative polymers of the copolymers are shown below. Symbol for dispersant NS: Naphthalene-based admixture (Mighty 150
; Kao Corporation Dispersant symbol MS: Melamine admixture (Mighty 150V-
2; manufactured by Kao Corporation.

Table 1 shows the mixing conditions of evaluation concrete as a concrete admixture .

[0046]

[Table 1]

For the production of concrete, the materials and admixture were mixed with a concrete mixer shown in Table 1 in a tilting mixer at 25 r
It was adjusted by kneading for 3 minutes at pm. After measuring the amount of air and fluidity (slump value), rotate at 4 rpm for 60 minutes,
After a minute, the amount of air and the slump value (cm) were measured. After adjusting the concrete, air entraining agent so that the air content is 4 ± 0.5%
(Vinsol: manufactured by Yamasou Chemical Co., Ltd.) and an antifoaming agent (Nicofix: manufactured by Nichika Chemical Co., Ltd.). Further, the initial slump value was adjusted so as to be 20 ± 1 cm by the addition amount of the present invention and the comparative admixture (the addition amount represents the addition amount to cement). The slump value was measured by the JIS-A1101 method. The measurement results are shown in Table 2.

[0048]

[Table 2]

Evaluation Results As is clear from Table 2, the admixture of the present invention has a remarkable air bubble retention property as compared with the comparative product. Moreover, it has excellent fluidity and exhibits excellent effects with little slump aging.

[0050]

When the concrete admixture according to the present invention is added to the cement composition, the quality control of the concrete becomes easy because the change of the air amount and the fluidity is small over a long period of time.

Claims (7)

[Claims] 1. A monomer (A) represented by the following general formula (a):
A monomer (B) represented by the following general formula (b), and a monomer (C) represented by the following general formula (c) and / or general formula (d)
A concrete admixture containing as an essential component a copolymer obtained by polymerizing. [Chemical 1] 2. A monomer (A) constituting the copolymer, a monomer
The reaction unit of (B) is monomer (A) / monomer (B) = 5/95 to 95/5
(% By weight) The concrete admixture according to claim 1. 3. A monomer (A) and a monomer (B) constituting the copolymer, wherein the reaction units of the monomer (C) are the monomer (A) and the monomer.
The concrete admixture according to claim 1 or 2, wherein (B) / monomer (C) = 10/90 to 99/1 (% by weight). 4. The copolymer according to claim 1, which is a copolymer obtained by further polymerizing a monomer copolymerizable with the monomers (A) to (C). Concrete admixture according to the item. 5. The average molecular weight of the copolymer is 1,0 in terms of weight average molecular weight (gel permeation chromatography method / standard substance sodium polystyrene sulfonate / water system).
It is 00-500,000, The concrete admixture according to any one of claims 1 to 4. 6. The concrete admixture according to claim 1, further comprising a known concrete admixture. 7. A known concrete admixture used in combination is
7. One or more selected from naphthalene sulfonate formaldehyde condensate, melamine sulfonate formaldehyde condensate, lignin sulfonate, phenol / sulfanylate formaldehyde condensate, and oxycarboxylate. Concrete admixture.