JP2001199751A - Method for producing cement dispersing agent - Google Patents

Abstract

(57) [PROBLEMS] To provide a method for obtaining a cement dispersant excellent in retention of air content and slump value. A reaction of a specific polyoxyalkylene alkyl ether monomer (B-1) with an alkenyl etherifying agent having 2 to 5 carbon atoms or a specific polyoxyalkylene alkenyl ether monomer (B-2 ) And an alkyl etherifying agent having 1 to 5 carbon atoms to obtain a specific monomer (A), and then copolymerizing the monomer (A) with a maleic acid-based monomer (C). When obtaining a cement dispersant in the monomer (B-1) or monomer (B-2) hydroxyl value of the monomer (OHVb) and the hydroxyl value of the monomer (A) (OHVa) The ratio and the molar ratio of the monomer (A) and the maleic acid-based monomer (C) are each within a specific range.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a cement dispersant.

[0002]

2. Description of the Related Art Naphthalene sulfonic acid formaldehyde condensate salts, melamine sulfonic acid formaldehyde condensate salts, polycarboxylic acid salts and the like are known as cement dispersants. While these show excellent water reducing effects, they do not have sufficient retention of air amount and slump value, and as improvements thereof, JP-A-63-285140, JP-A-2-163108, and JP-A-9-286647. The publication discloses a dispersant for cement containing a specific copolymer obtained from a vinyl polymerizable monomer having a polyoxyalkylene structure and a maleic acid-based monomer as an active ingredient.

[0003]

However, although the additive for cement described in the above publication improves the retention of the amount of air, it is still insufficient in the retention of the slump value.

An object of the present invention is to provide a method for obtaining a cement dispersant which is excellent in retaining air content and slump value.

[0005]

[In the formula, R ¹ : an alkenyl group having 2 to 5 carbon atoms R ² : an alkyl group having 1 to 5 carbon atoms EO: an oxyethylene group AO: an oxyalkylene group having 3 or 4 carbon atoms or an oxystyrene group n, m: n+m is 2 to 150 and m/(n+m) is 0 to 0.3. The EO and AO sequences may be random or block, and either of them may be on the R ¹ or R ² side. ]

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The production method of the present invention is represented by the general formula (B-
Compound represented by 1) [hereinafter referred to as a monomer (B-1)] or a compound represented by the following general formula (B-2) [hereinafter referred to as a monomer (B-2)] to the general formula (A ) To obtain a monomer (A) represented by,
And a step of copolymerizing the monomer (A) and the maleic acid-based monomer (C).

The monomer (B-1) is obtained by adding an alkylene oxide, which essentially requires ethylene oxide, to an alcohol having an alkyl group corresponding to R ² such as methanol. Examples of alkylene oxides other than ethylene oxide include propylene oxide, butylene oxide, and styrene oxide. R ² in the general formula (B-1) is preferably a methyl group or an ethyl group, particularly preferably a methyl group. Further, in the general formula (B-1), n and m are such that n+m is 2 to 15
0, preferably 3 to 125, particularly preferably 5 to 70, m/(n+
m) is 0 to 0.3, preferably 0 to 0.2, and more preferably 0.
The number is 0.1, and particularly preferably 0. This monomer (B-
The monomer (A-1) is obtained by reacting 1) with an alkenyl etherifying agent having 2 to 5 carbon atoms, preferably allyl chloride or methallyl chloride. The reaction molar ratio of both is preferably monomer (B-1)/alkenyl etherifying agent=1/0.6 to 1/10, more preferably 1/0.8 to 1/
5, and the reaction time and reaction temperature may be set appropriately.

The monomer (B-2) is R ¹ such as allyl alcohol.
Alcohol having an alkenyl group corresponding to
It can be obtained by adding the same alkylene oxide as in (B-1). R ¹ in the general formula (B-2) is preferably an allyl group or a methallyl group. Further, n and m in the general formula (B-2) are preferably in the same range as in the general formula (B-1). By reacting this monomer (B-2) with an alkyl etherifying agent having 1 to 5 carbon atoms, preferably dimethylsulfate, dimethyl carbonic acid, methyl chloride, ethyl chloride, particularly preferably methyl chloride, (A-1) is obtained. The reaction molar ratio of both is preferably monomer (B-2)/alkyl etherifying agent=1/0.6 to 1/10, more preferably 1/0.8 to 1/5.
Therefore, the reaction time, reaction temperature, etc. may be set appropriately.

In the present invention, the monomer (A) thus obtained is copolymerized with the maleic acid type monomer (C), but the monomer (B-1) or the monomer (B -2) hydroxyl value (OHVb) and monomer (A)
The hydroxyl value (OHVa) of is [(OHVa)/(OHVb)]×100=1 to 4
It is in the range of 0, preferably 1.5 to 30, and more preferably 2 to 25.

Examples of R ¹ alkenyl group having 2 to 5 carbon atoms in the general formula (A) include vinyl group, isopropenyl group,
Allyl group, methallyl group, 3-butenyl group, 2-methyl-1
Examples thereof include -butenyl group, 3-methyl-1-butenyl group, 2-methyl-3-butenyl group, 3-methyl-3-butenyl group and the like. Of these, the allyl group and the methallyl group are particularly preferable. In addition, R ² carbon number in the general formula (A) is 1
As the alkyl group of to 5, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group,
Examples thereof include an isopentyl group and a neopentyl group. Of these, a methyl group and an ethyl group are preferable, and a methyl group is particularly preferable. Further, n and m in the general formula (A) are the general formula (B-
The range similar to 1) is preferable.

Further, as the maleic acid type monomer (C),
Examples thereof include maleic anhydride, maleic acid, and maleic acid salts, and maleic anhydride is preferable. The maleic acid-based monomer may be used alone or in various kinds. Examples of the maleate salt include mono- or dialkali metal salts such as lithium salt, sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt, ammonium salt such as ammonium salt and diammonium salt. be able to.

Other copolymerizable monomers may be used to the extent that they do not affect the effects of the present invention. Examples of such a monomer include styrene, vinyl acetate,
Acrylic acid, methacrylic acid, alkenyl (C2-C2
5) Sulfonic acid, maleic acid ester and the like can be mentioned, and these may be salts. The proportion of these other copolymerizable monomers is preferably 30% by weight or less based on the total amount of the monomers (A) and (C).

In the present invention, the molar ratio of the monomer (A) to the maleic acid type monomer (C) is (A)/(C)=10/90 to 80/20,
Preferably 30/70 to 70/30, particularly preferably 40/60 to 60
It is in the range of /40. When the molar ratio of the monomers (A) and (C) is within the above range, the performance such as a good water reducing effect can be sufficiently exhibited.

The copolymerization reaction of the monomers (A) and (C) is carried out by solution polymerization of these monomers in water, an organic solvent or a mixed solvent of water and a hydrophilic organic solvent. Alternatively, it can be carried out by bulk polymerization in a system using no solvent at all. The reaction time, reaction temperature, etc. may be set appropriately.

As a polymerization initiator in an organic solvent or when no solvent is used, an organic peroxide type initiator such as benzoyl peroxide, or an azo type polymerization initiator such as 2,2′-azobisisobutyronitrile Can be used. When the polymerization is carried out in an aqueous system, water-soluble polymerization initiators such as hydrogen peroxide, hydroperoxides such as tert-butyl hydroperoxide, persulfates such as potassium persulfate and ammonium persulfate can be used. Further, the obtained copolymer, if necessary, part or all of the maleic anhydride unit is ring-opened by hydrolysis to give a maleic acid unit, and further part or all of the maleic acid unit is neutralized with an alkali. Can be harmonized. Examples of alkalis used for neutralization include hydroxides, carbonates or hydrogen carbonates of alkali metals such as lithium, sodium and potassium, hydroxides of alkaline earth metals such as magnesium and calcium, monoethanolamine, diethanolamine and triethanolamine. Examples thereof include alkanolamines, etc., ethylamines, diethylamines, triethylamines, and other alkylamines, and ammonia. These can be used alone or in combination of two or more.

The amount of the cement dispersant obtained according to the present invention is usually 0.01 to 3 as a solid content with respect to the cement.
It is preferable that the amount is 0.04 to 1% by weight from the viewpoints of water reduction property, slump loss prevention property, setting time and workability.

The cement to which the cement dispersant obtained according to the present invention can be applied includes ordinary Portland cement, early strength Portland cement, super early strength Portland cement, moderate heat Portland cement, sulfate resistant Portland cement and the like. Cement, blast furnace cement, silica cement, mixed cement such as fly ash cement, or these cements, blast furnace slag, fly ash, silica fume, cement that combines admixtures such as limestone, further belite cement, oil well cement, Specific cements such as high-sulfate slag cement, alumina cement, magnesia cement, and acid-resistant cement can be mentioned. These cements can be used alone or in combination of two or more, if necessary. The method of using the cement dispersant obtained according to the present invention is used by preliminarily dissolving it in water used for mortar or concrete, adding it at the same time as pouring water, or adding it from the time of pouring water until kneading. It is also possible to use it by adding it to the cement composition once kneaded. In addition, a powdered product such as being supported on a carrier may be premixed with cement. The cement dispersant obtained by the present invention can be used in combination with other cement additives, if necessary, to the extent that the effect is not impaired. As other cement additives, naphthalene sulfonic acid formaldehyde condensate salt, melamine sulfonic acid formaldehyde condensate salt,
One or more cement dispersants selected from lignin sulfonates, polycarboxylates, oxycarboxylates, polycarboxylic acids having a polyalkylene glycol chain in the side chain, and salts thereof can be mentioned. In addition, air entraining agent, antifoaming agent, separation reducing agent, setting retarder, setting accelerator,
Examples include swelling agents, drying shrinkage reducing agents, rust preventives and the like.

[0018]

Examples Synthesis Example 1 Synthesis of Monomer B-1 A high-pressure type reaction vessel equipped with a stirrer was charged with 61.7 parts by weight of allyl alcohol and 1.2 parts by weight of potassium hydroxide, and after nitrogen replacement, the temperature was raised to 100 to 125° C., gauge. At a pressure of 49 to 441 kPa, 937.1 parts by weight of ethylene oxide was injected under pressure for 3 hours to cause reaction, and then 125°C.
After aging for 1 hour, the residual ethylene oxide was removed under reduced pressure to obtain a monomer B-1. Table 1 shows the structure and hydroxyl value of the monomer B-1. Synthesis of Monomer A-1 A high-pressure reactor equipped with a stirrer was charged with 985 parts by weight of Monomer B-1 and 62.9 parts by weight of sodium hydroxide, and after nitrogen replacement, the temperature was raised and dehydrated under reduced pressure at 115° C. for 3 hours. After treatment, 52.3 parts by weight of methyl chloride is 115°C and gauge pressure is 29.4 to 245 kPa.
Then press-fit for 3 hours and ripen at 115°C for 3 hours.
After neutralization with hydrochloric acid, dehydration was performed under reduced pressure, and the precipitated salt was filtered off to obtain Monomer A-1 shown in Table 1. Table 1 shows the structure and hydroxyl value of the monomer A-1.

Synthesis Example 2 Synthesis of Monomer B-2 16.1 parts by weight of methanol and 0.8 parts by weight of sodium methylate were charged in the container of Synthesis Example 1 and the temperature was raised after replacement with nitrogen to 100° C. to 12° C.
A mixture of 227.7 parts by weight of ethylene oxide and 299.9 parts by weight of propylene oxide was mixed at 4°C at a gauge pressure of 49 to 441 kPa at 5°C.
After pressurizing and reacting for 1 hour and aging at 125°C for 1 hour,
At the same temperature, 455.5 parts by weight of ethylene oxide was injected under pressure for 2 hours for reaction, and after aging for 1 hour, the remaining ethylene oxide was removed under reduced pressure to obtain a monomer B-2. Monomer B
The structure and the hydroxyl value of -2 are shown in Table 1. Synthesis of Monomer A-2 The container of Synthesis Example 1 was charged with 980 parts by weight of Monomer B-2 and 36.9 parts by weight of potassium hydroxide.
After dehydration treatment at ℃ for 3 hours, 39 parts by weight of allyl chloride was injected under pressure at 115 ℃ and gauge pressure of 19.6 to 245 kPa for 3 hours, aged at 115 ℃ for 3 hours, neutralized with 6N hydrochloric acid and dehydrated under reduced pressure. Then, the precipitated salt was filtered off and the monomer A shown in Table 1 was obtained.
-2 was obtained. Table 1 shows the structure and hydroxyl value of the monomer A-2.

Synthetic Example 3 Synthesis of Monomer B-3 By the same procedure as in Synthetic Example 2, 10.4 parts by weight of methanol and 1.1 parts by weight of sodium methylate were used, and ethylene oxide was used without using propylene oxide. 988.5 parts by weight were added all at once to obtain a monomer B-3. Table 1 shows the structure and hydroxyl value of the monomer B-3. Synthesis of Monomer A-3 By the same operation as in Synthesis Example 2, 982 parts by weight of Monomer B-3 was used instead of Monomer B-2, and potassium hydroxide was adjusted to 28.5
The monomer A-3 shown in Table 1 was obtained by using 33.2 parts by weight of methallyl chloride instead of allyl chloride. Table 1 shows the structure and hydroxyl value of the monomer A-3.

Synthesis Example 4 Synthesis of Monomer B-4 By the same procedure as in Synthesis Example 1, 28.4 allyl alcohol was added.
By weight, 1.4 parts by weight of potassium hydroxide and 970.2 parts by weight of ethylene oxide were used to obtain a monomer B-4. Table 1 shows the structure and hydroxyl value of the monomer B-4. Synthesis of Monomer A-4 By the same operation as in Synthesis Example 1, 986 parts by weight of Monomer B-4 was used in place of Monomer B-1, and sodium hydroxide was added to 29 wt.
Monomer A-4 shown in Table 1 was obtained by using 40.5 parts by weight of ethyl chloride instead of methyl chloride. Table 1 shows the structure and hydroxyl value of the monomer A-4.

Synthetic Example 5 Synthesis of Monomer B-5 By the same procedure as in Synthetic Example 2, 5.2 parts by weight of methanol, 1 part by weight of sodium methylate, and 993.8 parts by weight of ethylene oxide charged in the latter stage were used. Polymer B-5 was obtained. Table 1 shows the structure and the hydroxyl value of the monomer B-5. Synthesis of Monomer A-5 By the same operation as in Synthesis Example 2, 990 parts by weight of Monomer B-5 instead of Monomer B-2 and 3.9 parts by weight of Metallic Sodium instead of potassium hydroxide. , Allyl chloride 16.2
Monomers A-5 shown in Table 1 were obtained by using parts by weight. Monomer A
Table 1 shows the structure and hydroxyl value of -5.

Synthetic Example 6 By the same procedure as in Synthetic Example 1, 24.1 parts by weight of metallic sodium and methyl chloride were used instead of sodium hydroxide.
The monomer A-6 shown in Table 1 was obtained by using 53 parts by weight. Table 1 shows the structure and hydroxyl value of the monomer A-6.

Synthetic Example 7 By the same operation as in Synthetic Example 2, 981 parts by weight of the monomer B-3 obtained in Synthetic Example 3 was used instead of the monomer B-2, and metallic sodium was used instead of potassium hydroxide. Was used in an amount of 7.8 parts by weight and allyl chloride was used in an amount of 30.7 parts by weight to obtain a monomer A-7 shown in Table 1. Table 1 shows the structure and hydroxyl value of the monomer A-7.

Synthetic Example 8 By the same procedure as in Synthetic Example 1, 33.6 sodium hydroxide was added.
Monomers A-8 shown in Table 1 were obtained using 50 parts by weight of methyl chloride and 53 parts by weight of methyl chloride. Table 1 shows the structure and hydroxyl value of the monomer A-8.

Synthesis Example 9 Synthesis of Monomer B-6 By the same operation as in Synthesis Example 2, a monomer B-6 was obtained with 3.7 parts by weight of methanol and 995.2 parts by weight of ethylene oxide in the subsequent stage. Table 1 shows the structure and the hydroxyl value of the monomer B-6. Synthesis of Monomer A-9 By the same operation as in Synthesis Example 2, 989 parts by weight of Monomer B-6 in place of Monomer B-2 and 3 parts by weight of metallic sodium in place of Potassium Hydroxide. Using 15.9 parts by weight of allyl chloride, the monomer A-9 shown in Table 1 was obtained. Monomer A-9
The structure and the hydroxyl value are shown in Table 1.

[0027]

[Table 1]

Examples 1 to 5 and Comparative Examples 1 to 4 <Production of Cement Dispersant> 953 g of the monomer A-1 obtained in Synthesis Example 1, 98.1 g of maleic anhydride and 2,2'-in a reactor. 3.3 g of azobisisobutyronitrile and 452 g of toluene were added, and the mixture was reacted under a nitrogen gas atmosphere at 70° C. for 4 hours and then heated to 80° C. for 3 hours, and then toluene was removed at 110° C. under reduced pressure. A cement dispersant was obtained (Example 1). The cement dispersants of Examples 2 to 5 and Comparative Examples 1 to 4 were obtained with the combinations shown in Table 2 in the same manner as in Example 1. In Example 4, polymerization was performed without using a solvent.

[0029]

[Table 2]

(Note) NaAS: sodium allylsulfonate AIBN: 2,2'-azobisisobutyronitrile BPO: benzoyl peroxide.

<Evaluation of Cement Dispersant> The concrete materials having the formulations shown in Table 3 and the cement dispersant shown in Table 2 were kneaded at 25 r/min for 3 minutes using a tilting mixer to obtain fluidity (slump value). After measuring the amount of air, it was further rotated at 4 r/min for 60 minutes, and after 60 minutes, the amount of air and the slump value (cm) were measured. It should be noted that the initial slump value becomes 20 ± 1 cm with the air bubble entraining agent (Binsole: manufactured by Yamamune Chemical Co., Ltd.) and the defoaming agent (Nicofix: manufactured by Nichika Chemical Co., Ltd.) so that the air amount becomes 4 ± 0.5%. Thus, the amount of the cement dispersant added was adjusted (the added amount represents the amount of solid content added to the cement). The slump value was measured by the JIS-A1101 method. The measurement results are shown in Table 4.

[0032]

[Table 3]

[0033]

[Table 4]

(Note) NS: naphthalene dispersant (Mighty 150; Kao Corporation)
PC: Polycarboxylic acid type dispersant (FC-600S; manufactured by Nippon Shokubai Chemical Co., Ltd.)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 103:40 C04B 103:40 F term (reference) 4J027 AC01 AC02 AC03 AC04 AC07 AJ02 BA04 BA05 BA06 CB02 CB03 CB09 4J100 AE09P AE18P AE26P AJ09Q AK19Q AK20Q AK21Q AK24Q AK25Q AK26Q AK32Q BA04P BA05P BA06P BA08P BA09P BA16H BC43P CA04 CA31 HA08 HA61 HB37 HB39 HB43 HC43 JA67

Claims (3)

[Claims] 1. A compound represented by the following general formula (B-1) is reacted with an alkenyl etherifying agent having 2 to 5 carbon atoms,
Alternatively, a compound represented by the following general formula (B-2) and a carbon number of 1 to 5
By reacting with an alkyl etherifying agent of
A method for producing a cement dispersant in which a monomer (A) represented by (A) is obtained, and then the monomer (A) is copolymerized with a maleic acid-based monomer (C), (B-1) represented by a compound or a compound represented by the general formula (B-2) hydroxyl value (OHVb) and the monomer (A) hydroxyl value (OHV
a) is in the range of [(OHVa)/(OHVb)]×100=1-40, and the molar ratio of the monomer (A) and the maleic acid monomer (C) is
(A)/(C) = A method for producing a cement dispersant in the range of 10/90 to 80/20. General formula (A); R ¹ O[(EO) _n (AO) _m ]R ² General formula (B-1); R ² O[(EO) _n (AO) _m ]H General formula (B-2) R ¹ O[(EO) _n (AO) _m ]H [in the formula, R ¹ : an alkenyl group having 2 to 5 carbon atoms R ² : an alkyl group having 1 to 5 carbon atoms EO: an oxyethylene group AO: a carbon number 3 or 4 oxyalkylene group or oxystyrene group n, m: n+m is 2 to 150, and m/(n+m) is a number of 0 to 0.3. The arrangement of EO and AO may be random or block. It may be on the R ¹ or R ² side. ] 2. n and m in the general formula (B-1) or the general formula (B-2)
Is a number such that n+m=2 to 70. The method for producing a cement dispersant according to claim 1. 3. The maleic acid-based monomer is maleic anhydride, R ² in the general formula (B-1) is a methyl group or an ethyl group, and R ¹ in the general formula (B-2) is The method for producing a cement dispersant according to claim 1, which is an allyl group or a methallyl group.