JPH08109055A - Admixture for cement - Google Patents

Abstract

PURPOSE: To obtain an admixture for cement having excellent preventing effect on loss of slump, high water-reducing properties and excellent workability, comprising a copolymer of specific two kinds of polyoxyalkylene derivatives and a maleic acid as an active ingredient. CONSTITUTION: This admixture comprises a copolymer as an active ingredient which is composed of (A) a polyoxyalkylene derivative of formula I, (B) a polyoxyalkylene derivative of formula II and (C) one or more of maleic anhydride, maleic acid and a maleate and satisfies 99/1<=(a)/(b)<=60/40 and 30/70<= (a+(b)}/(c)<=70/30 when equivalents of copolymerizable double bonds of the components A, B and C are (a), (b) and (c), respectively. In the formula, R<1> is a 2-5C alkenyl; X is a 2-8 OH-containing compound residue; A<1> O is a 2-4C oxyalkylene group and 50-100mol% of the oxyalkylene group is oxyethylene group; n>=0; a=1-7, na=0-1,000; Z is a 2-8 OH-containing compound residue; A<2> O and A<3> O are a 2-4C oxyalkylene group; R<2> and R<3> are a 2-5C alkenyl group; m>=0; k>=0; b>=1; c>=1; b+c=2-8 ; mb+kc=0-1,1000.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an additive for cement.

[0002]

2. Description of the Related Art Naphthalene sulfonic acid formaldehyde condensate salt, melamine sulfonic acid formaldehyde condensate salt,
Lignin sulfonate and the like are used as a water reducing agent. In recent years, the demand for high strength has increased in concrete, and it has become necessary to reduce the amount of water in concrete compositions. Although the above-mentioned additives have the effect of reducing the amount of water in the concrete composition, it is unavoidable that the fluidity of the concrete composition decreases with time (so-called slump loss).

Various proposals have been made to prevent the slump loss. JP-A-60-16851 proposes a blend of a maleic anhydride copolymer of a powdery olefin and a water reducing agent such as a naphthalenesulfonic acid formalin condensate, but the separation easily occurs, There is a problem of non-uniformity. In JP-A-59-162162, a combination of a naphthalene sulfonic acid formalin condensate salt or a melamine sulfonic acid formalin condensate salt and an allyl alcohol alkylene oxide adduct-unsaturated dicarboxylic acid copolymer is used for preventing slump loss. Although disclosed to be effective, it is not always sufficient. JP-A-6
3-285140 discloses a copolymer of a polyoxyalkylene unsaturated ether and maleic anhydride, a hydrolyzate thereof or a salt of the hydrolyzate,
Also in this case, the slump loss is not always sufficient. JP-A-2-163108 proposes a copolymer of a polyoxyalkylene unsaturated ether and a maleic acid ester. However, when the alcohol forming the ester is bifunctional or more, it is insoluble or sparingly soluble in water and is difficult to use, and when it is monofunctional, the setting time is long.

[0004]

This slump loss is a major problem in the concrete industry, and an early solution has been desired. An object of the present invention is to provide an additive for cement which has an excellent slump loss prevention effect, a large water-reducing property and a good workability in use.

[0005]

Means for Solving the Problems As a result of intensive investigations by the present inventors in order to achieve the above object, the present invention has been completed. That is, the present invention provides (A) a polyoxyalkylene derivative represented by the general formula (1), (B) a polyoxyalkylene derivative represented by the general formula (2), and (C).
1 of maleic anhydride, maleic acid, maleate
Seed or two or more as an essential component, each component (A),
When the copolymerizable double bond equivalents of (B) and (C) are (a), (b) and (c) respectively, 99/1 ≦ (a)
/ (B) ≦ 60/40 and 30/70 ≦ {(a) +
(B)} / (c) A cement additive containing a copolymer satisfying the condition of 70/30 as an active ingredient.

[0006]

Embedded image

(Wherein R ¹ is a alkenyl group having 2 to 5 carbon atoms, X is a residue of a compound containing 2 to 8 hydroxyl groups,
A ¹ O is an oxyalkylene group having 2 to 4 carbon atoms, and 5
0 to 100 mol% is an oxyethylene group, n ≧ 0, a = 1
7 and na = 0 to 1000. )

[0008]

[Chemical 4]

(However, Z is a residue of a compound containing 2 to 8 hydroxyl groups, A ² O and A ³ O are oxyalkylene groups having 2 to 4 carbon atoms, and R ² and R ³ are 2 to 2 carbon atoms. 5 alkenyl groups, m ≧ 0, k ≧ 0, b ≧ 1, c ≧ 1, b + c =
2 to 8 and mb + kc = 0 to 1000. However, when Z is a residue of a compound containing three or more hydroxyl groups, m = k = 0 cannot be satisfied at the same time. )

As the alkenyl group having 2 to 5 carbon atoms represented by R ¹ of the general formula (1) of the component (A), vinyl group, allyl group, methallyl group, 3-butenyl group, 4-pentenyl group, 3 And a methyl-3-butenyl group. (A)
Examples of the compound containing 2 to 8 hydroxyl groups having X as the residue of the general formula (1) of the component and Z of the general formula (2) as the component (B) include polyphenols such as catechol, resorcin, and hydroquinone. Polyvalent ethylene glycol, propylene glycol, butylene glycol, dodecylene glycol, octadecylene glycol, neopentyl glycol, glycerin, diglycerin, polyglycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol, sorbitan, etc. Alcohol; saccharides such as xylose, glucose, fructose, galactose, maltose and sucrose, and their partial etherified products and partially esterified products.

The number of carbon atoms represented by A ¹ O in the general formula (1) is 2
Examples of the oxyalkylene group of to 5 include an oxyethylene group, an oxypropylene group, an oxybutylene group and an oxytetramethylene group. 50 to ^{10 of} that A ¹ O
0 mol% is an oxyethylene group. When the oxyethylene group content is less than 50 mol%, high water-reducing property cannot be obtained due to insufficient water solubility. Na in the general formula (1) is 0.
If it is more than 1000, the viscosity becomes high and the production becomes difficult.

Examples of the C 2-4 oxyalkylene group represented by A ² O and A ³ O in the general formula (2) include oxyethylene group, oxypropylene group, oxybutylene group,
An oxytetramethylene group can be mentioned. Examples of the alkenyl group having 2 to 5 carbon atoms represented by R ² and R ³ in the general formula (2) include vinyl group, allyl group, methallyl group, 3-butenyl group, 4-pentenyl group, 3-methyl-3-. A butenyl group can be mentioned. Mb + kc of the general formula (2) is 0 to 1000.
If it is more than 1000, the viscosity is high and the production is difficult.

Examples of the maleate salt include alkali metal salts such as lithium salt, sodium salt and potassium salt; alkaline earth metal salts such as magnesium salt and calcium salt; ammonium salt and organic amine salt. As the organic amine salt, methylamine salt, dimethylamine salt, trimethylamine salt, ethylamine salt, diethylamine salt, triethylamine salt, propylamine salt, butylamine salt, amylamine salt, hexylamine salt, octylamine salt,
Aliphatic or aromatic monoamine salts such as 2-ethylhexylamine salt, decylamine salt, dodecylamine salt, hexadecylamine salt, octadecylamine salt, oleylamine salt, linoleamine salt, aniline salt; ethylenediamine salt, tetramethylenediamine salt , Dodecyl-propylenediamine salt, tetradecyl-propylenediamine salt,
Hexadecyl-propylenediamine salt, octadecyl-
Polyamine salts such as propylenediamine salt, oleyl-propylenediamine salt, diethylenetriamine salt, triethylenetetramine salt, tetraethylenepentamine salt, pentaethylenehexamine salt; monoethanolamine salt,
Diethanolamine salt, triethanolamine salt, monoisopropanolamine salt, diisopropanolamine salt, triisopropanolamine salt, salts of alkylene oxide adducts thereof, and salts of alkylene oxide adducts of primary or secondary amines. And alkanolamine salts; and amino acid salts such as lysine salts and arginine salts. Of these, alkali metal salts, ammonium salts and alkanolamine salts are particularly preferable. The maleate also includes partial salts.

In the present invention, (A) a polyoxyalkylene derivative represented by the general formula (1), (B) a polyoxyalkylene derivative represented by the general formula (2), and (C) maleic anhydride, maleic acid, After obtaining a copolymer containing one or more of maleic acid salts as an essential component, it can be used as it is or can be used as a corresponding salt exemplified above by adding a basic compound. it can.

The copolymer of the present invention comprises (A) the general formula (1)
A polyoxyalkylene derivative represented by (B), a polyoxyalkylene derivative represented by the general formula (2), and (C)
1 of maleic anhydride, maleic acid, maleate
It can be easily obtained by copolymerizing one kind or two or more kinds of components with a known polymerization initiator. For example, it can be obtained by copolymerizing persulfate such as ammonium persulfate, potassium persulfate, sodium persulfate, or hydrogen peroxide in water as a polymerization initiator. At this time, a reducing agent such as ammonium sulfite can be used together with the polymerization initiator for the polymerization in water. At the time of polymerization, other copolymerizable components such as styrene, α-olefin and vinyl acetate may be mixed and copolymerized.

Of (A) the polyoxyalkylene derivative represented by the general formula (1), (B) the polyoxyalkylene derivative represented by the general formula (2), and (C) maleic anhydride, maleic acid, and a maleic acid salt. The copolymerizable double bond equivalent ratio of one or two or more components of each component (A),
When the copolymerizable double bond equivalents of (B) and (C) are (a), (b) and (c) respectively, 99/1 ≦ (a)
/ (B) ≦ 60/40 and 30/70 ≦ {(a) +
(B)} / (c) ≦ 70/30 is satisfied.

When the ratio (a) / (b) of the polyoxyalkylene derivative represented by the general formula (2) is smaller than this ratio, the slump loss preventing effect is small, and when it is large, the production is difficult because of high viscosity. If the range of {(a) + (b)} / (c) deviates from this range, unreacted substances increase during copolymerization, which is not preferable. The weight average molecular weight of the copolymer of the present invention is 2,000 to 1,000,000, preferably 1
It is from 10,000 to 100,000.

The additive concentration of the additive of the present invention is 0.01 to 3% by weight, preferably 0.04 to 1% by weight, based on the cement. The additive of the present invention is a naphthalene sulfonic acid formalin condensate salt, a melamine sulfonic acid formaldehyde condensate salt, other additives such as polycarboxylic acid compounds,
You may use together with a defoaming agent, an air entraining agent, a rust preventive agent, a setting accelerator, a setting retarder, etc.

[0019]

【Example】

Production Example 1 Polyoxyethylene 10 mol monoallyl ether 440 g, polyoxyethylene 10 mol diallyl ether 60 g, anhydrous in a four-necked flask equipped with a stirrer, a nitrogen blowing tube, a thermometer, and a reflux tube. 98 g of maleic acid, 15 g of ammonium persulfate and 300 g of water were charged and reacted under a nitrogen stream at 70 to 80 ° C. for 10 hours to obtain a copolymer. The weight average molecular weight of the copolymer by gel permeation chromatography (hereinafter abbreviated as GPC) is shown in Table 1-2.

[0020]

[Table 1]

Note 1) The inside of {} indicates that it is a random adduct. Note 2) C ₄ H ₈ O represents an oxytetramethylene group.

[0022]

[Table 2]

Note 3) ST represents styrene.

Production Examples 2 to 14 (A) The polyoxyalkylene derivative of the general formula (1), (B) the polyoxyalkylene derivative of the general formula (2), and (C) the maleic acid type shown in Table 1-1. Copolymers were obtained by carrying out the same reaction as in Production Example 1 except that the monomers, other monomers and initiators were used in the amounts shown in Table 1-2. The weight average molecular weight of the copolymer by GPC is shown in Table 1-2. In Production Example 12, the copolymer was not obtained because the reaction product gelled.

Production Examples 15 to 18 The copolymers of the production examples shown in Tables 1-1 and 1-2 and other additives were blended in the ratios shown in Table 2 to obtain mixtures.

[0027]

[Table 3]

Examples 1 to 11, 13, 14 Tests with concrete were carried out using the copolymers and mixtures obtained in Production Examples 1 to 11, 13, 14. The composition and test conditions are shown below. Composition (kg / m ³ ) Water 166 Normal Portland cement 450 Sand 681 Crushed stone 1032 Additives Shown in Table 3-1. Water / cement ratio 36.9% Fine aggregate ratio 39.9% Each of the above components was placed in a forced kneading mixer, kneaded for 2 minutes, and then taken out to obtain a flow value (according to JIS R 5201) and an air amount (according to JIS A 1116). Unit volume gravimetric method) was measured. Further, the mixture was transferred to a foldable mixer and mixed at 2 revolutions per minute, and after 30 minutes, 60 minutes and 90 minutes, the slump and the amount of air were measured. Also the setting time,
The compressive strength was also measured and these results were
The results are shown in Tables -1 and 3-2.

[0029]

[Table 4]

[0030]

[Table 5]

Comparative Examples 1 to 9 Using the compounds shown below as comparative examples, the same tests as in Examples 1 to 14 were conducted. The results are shown in Tables 3-1 and 3-2. Comparative Example 1 Naphthalenesulfonic acid formalin condensate sodium salt Comparative Example 2 Polyethylene glycol monoallyl ether maleic acid copolymer sodium salt Comparative Example 3 Mixture of 75% of the compound of Comparative Example 1 and 25% of the compound of Comparative Example 2 Comparative Example 4 Poly Copolymer of oxyethylene 11 mol monoallyl monomethyl ether and maleic anhydride Comparative Example 5 Polyoxyethylene 11 mol monoallyl monomethyl ether and maleic acid polyoxyethylene 11
Copolymer with Mono-esterified Product by Molar Monomethyl Ether Comparative Example 6 No Additive Comparative Example 7 (a) / (b) is outside the scope of the present invention in Comparative Example 7 Comparative Example 8 Compound in Production Example 13 { (A) + (b)} /
(C) is outside the scope of the present invention. Comparative Example 9 The compound of Production Example 14 is {(a) + (b)} /
(C) is outside the scope of the present invention

The compounding composition of Comparative Example 6 is as follows. That is, when the additive is not added, the cement mixture cannot be kneaded unless the amount of water is increased, so the composition was changed as follows. Composition (kg / m ³ ) Water 195 Normal Portland cement 450 Sand 652 Crushed stone 985 Water / cement ratio 43.3% Fine aggregate ratio 40.0%

In Comparative Examples 1 to 4 and 7, the slump value decreases with time and the fluidity decreases, whereas in Examples 1 to 14, the slump value does not decrease with time,
Liquidity is maintained. Comparative Examples 2, 4, and 5 have a long setting time. Further, in Comparative Example 8, the addition amount was
It is considered that unreacted maleic anhydride remains in a large amount as compared with the above, which is not preferable. Further, Comparative Example 9 is not preferable because a constant slump value cannot be obtained unless the addition amount is remarkably increased. In the case of Comparative Example 6 without additives,
When the amount of water is not increased, a constant slump value cannot be obtained, and the compressive strength is low, whereas when the additive of the present invention is used, the amount of water can be reduced and a constant slump value can be obtained. Therefore, the compressive strength is high.

[0034]

The additive of the present invention comprises a partially cross-linked copolymer of a copolymerizable polyoxyalkylene derivative having a specific structure and a maleic acid as an active ingredient, thereby having high slump loss prevention and high water reduction. And has excellent workability.

Claims (1)

[Claims] 1. A polyoxyalkylene derivative represented by (A) the general formula (1), (B) a polyoxyalkylene derivative represented by the general formula (2), and (C) maleic anhydride, maleic acid, a maleic acid salt. One or two or more of them are essential components, and the copolymerizable double bond equivalents of the respective components (A), (B) and (C) are (a), (b) and (c), respectively. , 99/1 ≦ (a) / (b) ≦ 60/40 and 30/70 ≦ {(a) + (b)} / (c) ≦ 70/30
An additive for cement containing a copolymer satisfying the requirements as an active ingredient. Embedded image (However, R ¹ is an alkenyl group having 2 to 5 carbon atoms, and X is 2
To a residue of a compound containing 8 hydroxyl groups, A ¹ O is an oxyalkylene group having 2 to 4 carbon atoms, and 50 to 100 mol% thereof is an oxyethylene group, n ≧ 0, a = 1 to 7, na = 0
~ 1000. ) (However, Z is a residue of a compound containing 2 to 8 hydroxyl groups, A ² O and A ³ O are oxyalkylene groups having 2 to 4 carbon atoms, and R ² and R ³ are alkenyl groups having 2 to 5 carbon atoms. Base, m
≧ 0, k ≧ 0, b ≧ 1, c ≧ 1, b + c = 2 to 8, mb
+ Kc = 0 to 1000. However, when Z is a residue of a compound containing three or more hydroxyl groups, m = k = 0 at the same time.
Never be. )