JPH07157349A - Additive for cement - Google Patents

Abstract

PURPOSE:To obtain an additive for cement having low air entraining property at the time of work, high water reducing property and low slump loss property by allowing a copolymer of a specified polyoxyalkylene compd. with maleic anhydride to react with two kinds of specified polyoxyalkylene compds. CONSTITUTION:This additive for cement contains a copolymer as an effective component. The copolymer is obtd. by allowing a copolymer (A) of a polyoxyalkylene compd. represented by the formula I with maleic anhydride to react with a polyoxyalkylene compd. (B) represented by the formula II and a polyoxyalkylene compd. (C) represented by formula III and satisfies relations represented by the inequalities IV, V. In the formula I, R<1> is 2-5C alkenyl, A<1>O is 2-4C oxyalkylene including at least 50mol% oxyethylene, R<2> is 1-18C hydrocarbon and (m) is 1-200. In the formula II, R<3> is 1-5C hydrocarbon and (n) is 1-4-200. In the formula III, R<4> zs 1-20C hydrocarbon, etc., A<2>O is 3-4C oxyalkylene, (x) is 0 or 1-20, (y) is 10-100, (z) is 0 or 1-20, y>= (x+z) and (C2H4O) and (A<2>O) chains are a block adduct.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel cement additive, more specifically, a cement which is uniform in an aqueous solution state, has little air entrainment during working, and has high water reducing property and low slump loss property. It relates to additives for use.

[0002]

Conventionally, as additives for cement compounds such as concrete and mortar, naphthalene sulfonic acid formaldehyde condensate salt, melamine sulfonic acid formaldehyde condensate salt, lignin sulfonate and the like have been used as water reducing agents. In recent years, the demand for high strength has increased in concrete, and it has become necessary to reduce the amount of water (unit water amount) in concrete compositions. Although the above-mentioned additives have the effect of reducing the amount of unit water in the concrete composition, they have a drawback that the deterioration of fluidity of the concrete composition which occurs over time, that is, so-called slump loss cannot be avoided. Therefore, in order to prevent this slump loss, a polycarboxylic acid compound containing a maleic acid compound as a copolymer component has been proposed.
(For example, JP-A-60-16851 and JP-A-59)
-162162, JP-A-63-285140, JP-A-2-163108 and the like. ) However, when these polycarboxylic compounds are used as a water reducing agent, the reduction of the unit water amount and the prevention of slump loss are improved, but the air entrainment during kneading and stirring is increased, and therefore the strength of the cured product is increased. There was a problem such as a drop.
Therefore, in most cases, it was necessary to use a drug having a defoaming effect (antifoaming agent) in combination in order to reduce air entrainment. Defoaming agents that are water-soluble or water-dispersible generally have poor defoaming properties, and relatively water-insoluble defoaming agents cause separation in water. On the other hand, when a polycarboxylic acid compound is used as a water reducing agent, in most cases, it is mixed in the concrete composition in the form of an aqueous solution in order to improve workability. Therefore, when the defoaming agent was added to the aqueous solution of the polycarboxylic acid compound, separation was caused over time, and operations such as redispersion or redissolution during the work were required. Further, if there are too many air bubbles in the concrete molded product, the quality of the appearance is deteriorated, and for the purpose of improvement thereof, a chemical admixture for concrete containing a monoester or diester of a polyoxyalkylene block polymer as a main component is disclosed. (Japanese Patent Laid-Open No. 61-
111960 gazette). However, although this product has an effect of improving the deterioration in appearance due to large bubbles, etc., it has the drawback that it cannot fully satisfy all of them in terms of air entrainment, water reduction and slump loss prevention. Have

[0003]

Under these circumstances, the present invention is uniform in an aqueous solution state, has little air entrainment during working, and has both high water reducing property and low slump loss property. It was made for the purpose of providing an additive for cement.

[0004]

Means for Solving the Problems As a result of intensive studies to develop a cement additive having the above-mentioned preferable properties, the present inventors have found that a specific polyoxyalkylene compound and maleic anhydride can be co-polymerized. Copolymers obtained by reacting a specific polyoxyalkylene compound having a slump loss preventing effect and a specific polyoxyalkylene compound having an antifoaming effect at a predetermined ratio with respect to the coalescence are uniform when made into an aqueous solution. However, they have found that they have low air entrainment and have high water reducing property and high slump loss preventing property, and have completed the present invention based on this finding.

That is, the present invention provides (A) (a) the general formula [1] R ¹ O (A ¹ O) _m R ² ... [1] (wherein R ¹ is an alkenyl group having 2 to 5 carbon atoms). , A ¹ O has at least 50 mol% of oxyethylene groups and has 2 carbon atoms
To an oxyalkylene group, R ² is a hydrocarbon group having 1 to 18 carbon atoms, and m is an integer of 1 to 200) and (b) a maleic anhydride as an essential unit. (B) general formula [2] R ³ O (C ₂ H ₄ O) _n H ... [2] (wherein R ³ is a hydrocarbon group having 1 to 5 carbon atoms, n is 1 to 20
Polyoxyalkylene compound represented by zero is an integer) and (C) the general formula ^{[3] R 4 O (C} 2 H 4 O) x (A 2 O) y (C 2 H 4 O) z H ... [3] [wherein R ⁴ is a hydrocarbon group or an acyl group having 1 to 22 carbon atoms, A ² O is an oxyalkylene group having 3 or 4 carbon atoms, x
Is 0 or an integer of 1 to 20, y is an integer of 10 to 100, z
Is 0 or an integer of 1 to 20 and satisfies the relation y ≧ x + z, and the (C ₂ H ₄ O) chain and the (A ² O) chain are block-like adducts] Obtained by reacting a compound and having the formulas [4] and [5]

[Equation 2] The present invention provides an additive for cement which comprises a copolymer satisfying the relationship of (3) as an active ingredient.

The present invention will be described in detail below. In the cement additive of the present invention, the copolymer of the component (A) used as a raw material of the copolymer used as the active ingredient is (a) a compound represented by the general formula [1] R ¹ O (A ¹ O) _m A polyoxyalkylene compound represented by R ² [1] and (b) maleic anhydride are essential monomers. In the above general formula [1], R ¹ is an alkenyl group having 2 to 5 carbon atoms, and specific examples thereof include a vinyl group, an allyl group, a methallyl group, a 3-butenyl group, a 4-pentenyl group, and a 3-methyl- group.
3-butenyl group etc. are mentioned. A ¹ O has 2 to 2 carbon atoms
4 oxyalkylene group such as oxyethylene group, oxypropylene group, oxybutylene group, oxytetramethylene group, etc., but it is necessary that at least 50 mol% is oxyethylene group. If this oxyethylene group is less than 50 mol%, the water solubility is insufficient and the water-reducing property is poor. Further, m is an integer of 1 to 200, and when m is larger than 200, the viscosity becomes high and the production becomes difficult. Further, R ² is a hydrocarbon group having 1 to 18 carbon atoms, and specific examples include a methyl group, an ethyl group,
Propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, amyl group, isoamyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group,
Nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, hexadecyl group, octadecyl group, oleyl group, phenyl group, benzyl group, cresyl group, butylphenyl group, octylphenyl group, nonylphenyl group, naphthyl group And saturated hydrocarbon groups, unsaturated hydrocarbon groups, aromatic groups, substituted aromatic groups and the like.

The copolymer of the component (A) uses the polyoxyalkylene compound represented by the general formula [1] as the component (a) and maleic anhydride as the component (b) as essential monomers. It can be easily obtained by copolymerizing these with an organic peroxide type initiator such as benzoyl peroxide or an azo type initiator such as azobisisobutyronitrile. At the time of this copolymerization, a solvent such as benzene, toluene or xylene can be used if necessary, and a copolymerizable monomer such as styrene or vinyl acetate can be added. Further, the component (a), a polyoxyalkylene compound represented by the general formula [1], and (b)
The molar ratio of maleic anhydride to the component is 3/7.
The range of ˜7 / 3 is preferable, and 1/1 is particularly preferable. In this way, the copolymer of the component (A) thus obtained may be used alone or in combination of two or more.
In the cement additive of the present invention, the copolymer used as an active ingredient is a copolymer represented by the general formula [2] R ³ O (C ₂ H ₄ ) which is the component (B) with respect to the copolymer of the component (A). O) _n H ... [2] A polyoxyalkylene compound represented by the general formula [3] R ⁴ O (C ₂ H ₄ O) _x (A ² O) _y (C ₂ H ₄₎ It is obtained by reacting a polyoxyalkylene compound represented by O) _z H ... [3]. In the above general formula [2], R ³ is a hydrocarbon group having 1 to 5 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group and a tert-butyl group. , Amyl group, isoamyl group, vinyl group, allyl group, methallyl group, 3-butenyl group, 4-pentenyl group, 3-methyl-3-butenyl group and the like. N is an integer of 1 to 200,
If this n is larger than 200, the viscosity becomes high and the production becomes difficult.

On the other hand, in the general formula [3], R ⁴ is a hydrocarbon group having 1 to 22 carbon atoms or an acyl group, and examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, an isopropyl group, Butyl group, isobutyl group, tert-butyl group, amyl group, isoamyl group, hexyl group, heptyl group, 2-ethylhexyl group, octyl group, nonyl group,
Decyl group, undecyl group, dodecyl group, tridecyl group,
Tetradecyl group, hexadecyl group, octadecyl group, oleyl group, behenyl group, phenyl group, benzyl group, cresyl group, butylphenyl group, octylphenyl group, nonylphenyl group, saturated hydrocarbon group such as naphthyl group, unsaturated hydrocarbon group , Aromatic groups, substituted aromatic groups and the like. Examples of the acyl group include acetic acid, propionic acid, butyric acid, isobutyric acid, caproic acid, caprylic acid, 2-
Ethylhexanoic acid, capric acid, undecylenic acid, lauric acid, myristic acid, palmitic acid, margaric acid,
Linear saturated acyl group, branched saturated acyl group, unsaturated derived from stearic acid, arachidic acid, behenic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid, erucic acid, isopalmitic acid, isostearic acid, benzoic acid, etc. Examples thereof include an acyl group and an aromatic acyl group. Further, A ² O is an oxyalkylene group having 3 or 4 carbon atoms, and specific examples thereof include an oxypropylene group, an oxybutylene group and an oxytetramethylene group. x and z are each 0 or an integer of 1 to 20, and when it is larger than 20, the water solubility becomes high and the defoaming effect becomes insufficient. y is an integer of 10 to 100, and if it deviates from this range, the defoaming effect becomes insufficient. x, y and z are y ≧ x +
It is necessary to satisfy the relation of z and (C ₂ H ₄ O)
The chains and (A ² O) chains are block adducts. The polyoxyalkylene compound as the component (B) may be used alone, or two or more kinds may be used in combination, and the polyoxyalkylene compound as the component (C) may be used in one kind, You may use it in combination of 2 or more type.

In the cement additive of the present invention, the copolymer used as an active ingredient is the polyoxyalkylene compound of the component (B) and the polyoxyalkylene compound of the component (C) with respect to the copolymer of the component (A). It can be obtained by reacting an oxyalkylene compound, and in this case, the compounds of the formulas [4] and [5]

[Equation 3] It is necessary to satisfy the relationship of. [The number of hydroxyl equivalents of the component (B) + the number of hydroxyl equivalents of the component (C)] / (equivalent number of acid anhydride groups in the component (A)) exceeds the above range, the slump loss preventing effect becomes insufficient. . Further, when the value of (weight of component (C) / weight of component (A) + weight of component (B)) × 100 is less than 0.01, the defoaming effect is not sufficiently exerted, and the value exceeds 5 However, the remarkable improvement of the defoaming effect is not seen. The reaction product of the copolymer of the component (A) with the polyoxyalkylene compound of the component (B) and the polyoxyalkylene compound of the component (C) is an alkali such as sodium hydroxide, potassium hydroxide or sodium methylate. Metal compound; Alkaline earth metal compound such as calcium hydroxide, magnesium hydroxide; Mixture in the presence of ammonia, amines such as monoethanolamine, diethanolamine, triethanolamine, etc., or easily obtain by mixing and heating You can It can also be obtained by mixing and heating without a catalyst.

The cement additives of the present invention include, if desired, alkali metal compounds such as sodium hydroxide and potassium hydroxide; alkaline earth metal compounds such as calcium hydroxide and magnesium hydroxide; ammonia, monoethanolamine and diethanolamine. Alternatively, amines such as triethanolamine may be added. The additive for cement of the present invention is usually added in an amount of 0.01 to 3% by weight, preferably 0.04 to 1% by weight, based on cement. If the added amount is less than 0.01% by weight, the effects of the present invention such as low air entrainment, high water-reducing property and low slump loss property are not sufficiently exhibited, and if it exceeds 3% by weight, the effect of the present invention is exhibited. However, workability is deteriorated due to delay of setting or the like, which is not preferable. Cement additive of the present invention, in the range that does not impair its performance, naphthalene sulfonic acid formalin condensate salt, melamine sulfonic acid formaldehyde condensate salt, other additives such as polycarboxylic acid compounds, or air entraining agent, You may use together with a rust preventive agent, a setting accelerator, a setting retarder, etc.

[0011]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. Production Example 1 Copolymer of polyoxyethylene monoallyl monomethyl ether represented by copolymer name A in Table 1 and maleic anhydride was placed in a four-necked flask equipped with a stirrer, a nitrogen blowing tube, a thermometer, and a reflux condenser. Polyoxyethylene monoethyl ether 78 represented by compound name J in Table 2 was added to 1000 g of the combined product.
7.7 g, polyoxypropylene polyoxyethylene monooleyl ether 3.6 represented by compound name P in Table 3
g and 0.5 g of sodium methylate were charged and reacted under a nitrogen stream at 100 ± 5 ° C. for 3 hours to obtain a target copolymer. When this copolymer was dissolved in water to prepare a 20 wt% aqueous solution, it was a homogeneous liquid. Production Examples 2 to 22 In the same manner as in Production Example 1, the copolymers shown in Table 1 were reacted with the polyoxyalkylene compounds shown in Tables 2 and 3 at the ratios shown in Table 4, The target copolymer was obtained. All 20 wt% aqueous solutions of these copolymers were homogeneous liquids.

[0012]

[Table 1]

[0013]

[Table 2]

[0014]

[Table 3]

[0015]

[Table 4]

Production Example 23 100 g of the copolymer obtained in Production Example 2 and 100 g of naphthalenesulfonic acid formaldehyde condensate sodium salt were mixed to prepare a 20 wt% aqueous solution. This aqueous solution was a homogeneous liquid. Examples 1 to 23 Evaluation tests using mortar were performed using the 20 wt% aqueous solutions obtained in Production Examples 1 to 23. The composition and test conditions are shown below. Composition (g) Water 180 Cement 360 Sand 1080 Additive Amount shown in Table 5 Water / cement ratio 50.0% Put each of the above components in a mortar mixer, mix for 3 minutes, and then take out. It was measured. After 30 minutes and 60 minutes, the flow value and the air amount were measured. The results are shown in Table 5.

Comparative Examples 1 to 5 Using the compounds shown below as comparative examples, the same tests as in Examples 1 to 23 were conducted. The results are shown in Table 5. Comparative Example 1 Naphthalenesulfonic acid formalin condensate sodium salt Comparative Example 2 Copolymer B in Table 1 Comparative Example 3 1000 g of Copolymer B in Table 1 was used in the same manner as in Production Example 1 with Compound J316.8 g in Table 2. What has reacted. Comparative Example 4 500 g of a 20 wt% aqueous solution of the compound of Comparative Example 3
Dissolved in 0.2 g of the compound P shown in Table 3. The aqueous solution separated after 2 days. Comparative Example 5 No additive. However, only Comparative Example 5 has the following composition. Composition (g) Water 225 Cement 360 Sand 1080 Water / cement ratio 62.5%

[0018]

[Table 5]

From the above results, it is understood that Examples 1 to 23 have higher water reducing properties and higher slump loss preventing properties than the sodium salt of naphthalenesulfonic acid formalin condensate of Comparative Example 1. Further, Comparative Examples 2 and 3 in which the compound having the defoaming effect represented by the general formula [3] [Component (C)] was not reacted.
It can be seen from the comparison with (1) that the product of the present invention has low air entrainment. The performance of Comparative Example 4 is almost the same as that of Example 3, but
The aqueous mixture solution of Comparative Example 4 was not practically preferable because separation occurred with time. In the system in which the additive of Comparative Example 5 was not used, the predetermined flow value could not be obtained unless the amount of water was increased.

[0020]

The additive of the present invention is a copolymer of a specific polyoxyalkylene compound and maleic anhydride, a polyoxyalkylene compound having a specific slump loss preventing effect and a polyoxyalkylene having a defoaming effect. By using the reaction product with the compound as an active ingredient, it is uniform as an aqueous solution, and when used in mortar, concrete, etc., it has low air entrainment and shows high water reducing property and high slump loss prevention performance. It is a thing.

Claims (1)

[Claims] 1. (A) (a) General formula [1] R ¹ O (A ¹ O) _m R ² ... [1] (wherein R ¹ is an alkenyl group having 2 to 5 carbon atoms, A ¹ O Has 2 carbon atoms in which at least 50 mol% is an oxyethylene group
To an oxyalkylene group, R ² is a hydrocarbon group having 1 to 18 carbon atoms, and m is an integer of 1 to 200) and (b) a maleic anhydride as an essential unit. (B) general formula [2] R ³ O (C ₂ H ₄ O) _n H ... [2] (wherein R ³ is a hydrocarbon group having 1 to 5 carbon atoms, n is 1 to 20
Polyoxyalkylene compound represented by zero is an integer) and (C) the general formula ^{[3] R 4 O (C} 2 H 4 O) x (A 2 O) y (C 2 H 4 O) z H ... [3] [wherein R ⁴ is a hydrocarbon group or an acyl group having 1 to 22 carbon atoms, A ² O is an oxyalkylene group having 3 or 4 carbon atoms, x
Is 0 or an integer of 1 to 20, y is an integer of 10 to 100, z
Is 0 or an integer of 1 to 20 and satisfies the relation y ≧ x + z, and the (C ₂ H ₄ O) chain and the (A ² O) chain are block-like adducts] Obtained by reacting a compound and having the formulas [4] and [5] An additive for cement containing a copolymer satisfying the relationship of as an active ingredient.