JPH09110493A - Admixture for cement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve dispersibility and slump holding property by incorporating a polyoxyalkylene monoamine, a monomer which can condense and copolymerize with the monoamine to produce formaldehyde, a compd. which produces sulfonic groups and a condensed copolymer containing formaldehyde. SOLUTION: This admixture for cement is obtd. by copolymn. and condensation of (A) polyoxyalkylene monoamine expressed by the formula, (B) one or more kinds of monomers selected from melamine (deriv.), phenol (deriv.) and urea (deriv.) which can condense and copolymerize with the component (A) to produce formaldehyde, (C) a compd. which produces sulfonic groups, and (D) formaldehyde by the molar ratio, A:B:C:D of (0.05 to 0.5):1:(0.3 to 4):(1 to 6) under condition of pH=4 to 12. In the formula, R1 is 1-5C alkyl group; R2 is 1-5C alkylene group; AO, BO are each block and/or random 2-5C oxyalkylene, and (m) and (n) are each 0 to 100 satisfying 100>=(m)+(n)>=4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an admixture for a cement or a cement composition, and more particularly, to the addition of a hydraulic cement composition such as a cement paste, mortar, concrete or the like when kneading to improve the workability. The present invention relates to a cement admixture to be improved.

[0002]

2. Description of the Related Art
Various types of organic compounds added to cement, particularly as a cement water reducing agent, are known. Representative examples thereof include salts of highly condensed β-naphthalenesulfonic acid formaldehyde, salts of melaminesulfonic acid formaldehyde condensate, ligninsulfonic acid salts, oxycarboxylic acids, and the like. When these compounds are added to a kneaded product composed of cement, water and aggregate, sufficient workability can be obtained even if the amount of water during kneading is reduced. Therefore, there is an advantage that workability is improved, and since the water-cement ratio can be reduced, it is useful for enhancing the strength of a hydraulic cement composition such as cement paste, mortar, and concrete.

[0003] However, in general, cement paste,
Mortar, hydraulic cement composition such as concrete,
With the passage of time after kneading, the fluidity is lost. This phenomenon occurs when the organic compound added as the cement water reducing agent is used, and particularly, β-
This is remarkable when a salt of a highly condensed naphthalenesulfonic acid formaldehyde or the like is used, and depending on the composition of the concrete, a phenomenon in which the slump is reduced to half or less within 30 minutes after kneading is observed. Due to the phenomenon that the slump loss is large, the following problems occur. In other words, the concrete composition may be pumped by pumping concrete, but if the pumping is temporarily interrupted due to a break time or various troubles at that time, the pumping pressure may suddenly increase when resuming, And piping may be blocked. Also, due to reduced fluidity, the compact may not be sufficiently compacted in the mold and a defective portion may be generated.

In order to suppress slump loss, various water reducing agents have been developed in the past. For example, a substance in which the functional group is dissociated by an alkali in concrete, a so-called sustained-release high-performance water reducing agent (Japanese Patent Publication No. 63-5346) is known. Further, a water-soluble vinyl copolymer (Japanese Patent Publication No. 6-60042) is known, in which a new functional group appears by being hydrolyzed in an alkali and suppresses slump loss. Further, for the purpose of maintaining a slump due to steric hindrance of a molecular chain, a polyalkylene glycol monoester monomer having an unsaturated bond and a (meth) acrylic acid monomer and / or an unsaturated dicarboxylic acid monomer (JP-B-59-18338, JP-B-2)
JP-B-7897, JP-B-2-7898, JP-B-2-7901, JP-B-2-8983, JP-B2-111542, JP-B5-111057, and JP-B6-88817. And water-soluble vinyl copolymers (these are generically referred to as polycarboxylic acid type). Further, a condensate in which a polyalkylene glycol chain is introduced into an aromatic compound (Japanese Patent Laid-Open No. 6-3 / 1994)
No. 40459) has also been recently developed.

However, while these compounds show excellent flow effect, they have various problems. First,
In the case of slow-release high-performance water reducing agents that work with alkali in concrete and water-soluble vinyl copolymers that are newly hydrolyzed by alkali hydrolysis to replenish functional groups and suppress slump loss,
Carboxyl groups will appear over time. This carboxyl group has a strong binding force with calcium ions. Therefore,
These compounds have a problem that calcium ions in the cement are trapped and the setting delay is increased.

Furthermore, a polycarboxylic acid having an oxyalkylene chain in the molecule has high air entrainment, and it is difficult to control the amount of air in concrete. In reality, the amount of air is controlled using an antifoaming agent, but the amount of air fluctuates greatly depending on the kneading conditions in the concrete mixer, the agitator conditions of the mixer truck, and the transport time,
There is a problem that it is difficult to use. Furthermore, (meta)
Since copolymerization is carried out using acrylic acid-based monomers and / or unsaturated dicarboxylic acid-based monomers, these compounds have a carboxyl group in the molecule. However, there is a problem that is increased. That is, the initial strength of the cement mortar or concrete decreases. In addition, when a large slump is used, that is, when soft mortar or concrete is used, material separation may occur, which is a problem.

Further, a condensate in which a polyalkylene glycol chain is introduced into an aromatic compound has a problem that a flow effect similar to that of a polycarboxylic acid having an oxyalkylene chain in a molecule cannot be recognized.

[0008]

The inventors of the present invention have conducted extensive studies to solve these problems, and as a result, have found that a cocondensate having a specific molecular structure is excellent without causing a significant delay in curing. The present invention has been found out by showing a dispersion effect and a slump holding effect and further having a remarkable material separation resistance.

That is, the present invention relates to a polycondensation product containing polyoxyalkylene monoamine (A), polyoxyalkylene monoamine, formaldehyde co-condensable monomer (B), sulfone group-forming compound (C) and formaldehyde. A cement admixture consisting of

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The polyoxyalkylene monoamine (A) has the general formula (1) R ₁ O— (AO) _m (BO) _n —R ₂ —NH ₂ where R ₁ : an alkyl group having 1 to 5 carbon atoms R ₂ : a carbon number 1-5 alkylene group AO, BO: C2-C5 oxyalkylene group AO, BO is block and / or random m, n: integer of 0-100. However, the compounds represented by 100 ≧ m + n ≧ 4 are polyoxyalkylene monoamines such as polyoxyethylene monoamine, polyoxypropylene monoamine, and polyoxyethyleneoxypropylene monoamine. This oxyalkylene moiety preferably has 2 to 5 carbon atoms. If the number of carbon atoms exceeds 5, the water solubility decreases, and not only cocondensation becomes difficult, but also an excellent flow effect cannot be obtained, which is not preferable.

The oxyalkylene may be one kind, or two or more kinds of oxyalkylene may be bonded in a block or random manner. The repeating unit is preferably 4 to 100, and more preferably 7 to 70. If this repeating unit is less than 4,
The obtained cement admixture has an insufficient flow effect and an insufficient slump loss suppression effect, which is not preferable. Further, if the number exceeds 100, the cocondensation may not proceed well, which is not preferable.

The step of adding the compound represented by the general formula (1) may be preliminarily charged in the reaction apparatus at the start of the reaction, or when the formaldehyde co-condensation reaction is carried out under the condition of pH in a weakly acidic range. It may be added immediately before or immediately after the pH adjustment.

The addition amount of the compound represented by the general formula (1) is 1 mol of the monomer (B) capable of co-condensing polyoxyalkylene monoamine and formaldehyde.
0.005-0.5 mol is preferable, 0.01-0.3
5 mol is more preferred. When the amount of the compound represented by the general formula (1) is less than 0.005 mol, the slump loss suppressing effect is not sufficiently expressed, which is not preferable. Further, if it exceeds 0.5 mol, it may be difficult to control the reaction, and further, it is economically disadvantageous, which is not preferable.

The monomer (B) capable of co-condensing polyoxyalkylene monoamine and formaldehyde is represented by the general formula (11) Compounds represented by, that is, melamine, methylol group-containing melamine, sulfomethyl group-containing melamine, and the like can be used. In the case of sulphomethyl group-containing melamine, salts thereof can also be used. Salts include inorganic salts, i.e., alkali metal salts or alkaline earth metal salts such as potassium, sodium, and magnesium;
Alternatively, organic salts, that is, ammonium salts, monoethanolamine salts, diethanolamine salts, and the like can also be used.

In addition, as the other, the general formula (lll) The compound represented by, that is, phenol, or alkylphenols such as cresol, p-t-butylphenol, and p-t-amylphenol, or a sulfonic acid or a salt of sulfonic acid thereof can also be used. As the salt, an inorganic salt or an organic salt thereof can be used as in the case of the general formula (11). Of these, phenol, phenolsulfonic acid and salts thereof are preferable from the economical and reactivity viewpoints.

Further, the general formula (IV) The compound represented by, that is, urea, methylol group-containing urea, and sulfomethyl group-containing urea can also be used. In the case of urea containing a sulfomethyl group, the general formula (11)
Similarly to the above, inorganic salts and organic salts thereof can also be used.

In the present invention, the general formula (11),
One or more kinds of the monomers represented by the general formula (lll) and the general formula (lv) can be used in combination.
l) is the most preferable in terms of economical efficiency and reactivity.

As the compound (C) which forms a sulfone group, known sulfonating agents such as fuming sulfuric acid, sodium sulfite, sodium bisulfite, sodium pyrosulfite and sulfur dioxide can be used.

These sulfonating agents have previously been represented by the general formula (l
l), may be used when introducing a sulfomethyl group into a corresponding raw material of the general formula (IV), or may be used after synthesizing a cocondensate with formaldehyde to directly introduce the sulfomethyl group into the cocondensate. You may.

The sulfomethyl group can be introduced into melamine by a known method. That is, it can be introduced by addition-condensing melamine with formaldehyde to obtain methylolmelamine, and then actuating a sulfonating agent to replace it with a hydroxyl group. It is known that 6 mol of formaldehyde is addition-condensed as methylol group to 1 mol of melamine. In the present invention, since 2 moles of methylol groups are likely to be used for cocondensation, sulfomethyl groups can be introduced into the remaining 4 moles of methylol groups at the maximum. Considering the economical aspect and the flow effect of the obtained cocondensate, the introduction amount of the sulfomethyl group is preferably 0.3 to 4 mol, and more preferably 0.5 to 2 mol. The same applies to the case of introducing a sulfomethyl group into urea, and the introduction amount is preferably 0.3 to 2 mol, and more preferably 0.5 to 1.5 mol, per 1 mol of urea.

The formaldehyde used in the synthesis of these formaldehyde cocondensates is usually 3
Those having a concentration of 0 to 60% by weight can be used. Further, if necessary, paraform can be used in combination. The formaldehyde is preferably used in an amount of 1 to 6 times the total number of moles of the polyoxyalkylene monoamine and the monomer (B) capable of formaldehyde cocondensation. In consideration of economy, ease of the condensation reaction, and the like, it is more preferable to use 1.5 to 4 moles.

The formaldehyde co-condensation reaction has a pH of 4-1.
In the range of 2, the so-called weakly acidic region to the basic region is usually used. A pH of 4 or less is not preferable because the reaction cannot be controlled, for example, the condensation reaction may proceed rapidly and cause gelation. The formaldehyde may be added in advance in the reactor, or formaldehyde may be added dropwise for the reaction.

The composition of the compounds constituting the admixture in the present invention is important. That is, the molar ratio of polyoxyalkylene monoamine (A): polyoxyalkylene monoamine and formaldehyde co-condensable monomer (B): sulfone group-forming compound (C): formaldehyde is (0.005 to 0). .5): 1: (0.3-
4): (1 to 6) is preferable, and (0.01 to 0.35): 1: (0.5 to 2): is more preferable.
(1.5-4) is preferable.

Next, an example of a specific method for producing the cement admixture in the present invention will be shown below, but the present invention is not limited to this. . Specific Example 1 A compound represented by the general formula (11), formaldehyde and water were placed in a four-necked flask equipped with a stirrer, a thermometer, a reflux tube and a dropping funnel, and the temperature was raised to 60 to 90 ° C.
The reaction is carried out under basic condition for 0.5 to 2 hours. Next, the compound represented by the general formula (111) was charged, and the amount was further adjusted to 60 to 9
The reaction is carried out at 0 ° C for 0.5 to 2 hours, then cooled to 30 to 50 ° C, and the compound represented by the general formula (IV) is added dropwise from the dropping funnel over 10 to 120 minutes. Further, after reacting at 50 to 90 ° C. for 0.5 to 2 hours, general formula (1) and a compound (C) which forms a sulfonic group are added, and 0.5 at 60 to 90 ° C.
Let react for ~ 3 hours. Furthermore, the system is made weakly acidic to 50
The reaction is allowed to proceed until the viscosity of the solution reaches a predetermined value at -80 ° C. When the viscosity of the solution reaches a predetermined value, it is neutralized to stop the reaction. The predetermined viscosity for stopping the reaction depends on the non-volatile content of the solution, but when the non-volatile content is 35%, the value measured by the B-type viscometer is 10 to 500 cp / 25 ° C.
Is preferable and 15-300 cp / 25 degreeC is more preferable. When the viscosity is out of this range, even if the obtained co-condensate is added to the cement composition, the flow effect and the slump loss suppressing effect may not be sufficiently exhibited.

The compound represented by the general formula (1) may be charged any time as long as it is before the step immediately after changing the liquid property in the system to weakly acidic. That is, when the initial water was charged, before and after the addition of the general formula (lll), the general formula (lv)
Can be added before or after the dropwise addition of the compound (C), before or after the addition of the compound (C) that generates a sulfone group, and immediately before or after the liquid property in the system is changed to weakly acidic.
Further, for the purpose of cooling, the charged water may be divided into the respective steps, or the addition of each compound may be divided and added. Furthermore, you may change the addition order of each compound.

Specific Example 2 A compound represented by the general formula (l), the general formula (ll) and the general formula (lll), formaldehyde, water, and a compound (C) which produces a sulfo group are mixed with a stirrer, a thermometer, A 4-necked flask equipped with a reflux tube was charged, and the mixture was heated to 60-
The reaction is carried out at 90 ° C for 0.5 to 5 hours. Furthermore, the inside of the system is set to a weakly acidic region and the reaction is performed at 40 to 80 ° C. for 0.5 to 10 hours. When the viscosity of the solution reaches a predetermined value, it is neutralized to stop the reaction. The specific viscosity for stopping the reaction is the specific example 1
Same as. In addition, the charging time of the compound represented by the general formula (1) may be any time before the step immediately after the liquid property in the system is changed to weak acid as in Example 1.

Regarding the method of using the admixture of the present invention,
Other known cement admixtures such as an air entraining agent, an antifoaming agent, a setting accelerator, a setting retarder, a rust preventive, an antiseptic, a waterproofing agent, a strength accelerator and the like can be used in combination. In addition, the method of use is usually mixed in kneading water and added to the cement composition.However, the method of adding the cement composition at once or adding it separately at the time of preparing the cement composition, the method of adding the cement composition after kneading, Any method such as the method of adding may be used. The cement admixture according to the present invention varies depending on the composition and the use of the cement composition, but is usually 0.
It is used in a proportion of 01 to 2.0% by weight, preferably 0.05 to 1.0% by weight. If the amount used is less than 0.01% by weight, the dispersion fluidity tends to decrease, and the slump loss preventing effect tends to decrease. On the other hand, if it exceeds 2.0% by weight, it tends to cause material separation and makes it difficult to obtain a homogeneous cured product, and is economically disadvantageous.

The cement admixture according to the present invention can be applied to concrete and mortar prepared by using various Portland cement, fly ash cement, blast furnace cement, silica cement, various mixed cements and the like.

The reason why the cement admixture of the present invention exhibits excellent flow effect, slump loss suppressing effect and material separation resistance without showing retardation of setting is not clear, but it is presumed as follows. That is, since the cement admixture of the present invention has a sulfone group in the molecule similarly to the conventional high-performance water reducing agent, the dispersibility of the cement particles is enhanced by its electric repulsion. Further, when the cement admixture of the present invention is adsorbed on the cement particles, it is considered that the polyoxyalkylene group in the molecule extends to the outside of the cement particles. It is considered that a hydration layer is formed around the polyoxyalkylene group extending to the outside, and the steric hindrance effect associated therewith holds the dispersibility of the cement particles for a long time and suppresses slump loss. Furthermore, the conventional sustained-release high-performance water reducing agent,
Since polycarboxylic acid type water reducing agents and alkaline hydrolysis type water reducing agents do not have a carboxyl group having a high chelating ability with Ca ions in the molecule, they are not expected to show a setting retarding property. Therefore, the cement admixture of the present invention has excellent dispersion performance, slump loss suppressing effect, and material separation resistance.

The cement admixture of the present invention will be described in more detail in the following examples, but the present invention is not limited thereto. In addition, all percentages or parts described below as units of numerical values are% by weight or parts by weight unless otherwise specified.

[0031]

【Example】

Synthesis of Condensate Table 1 shows the physical property values of the polyoxyalkylene monoamines used in the present invention. As a typical polyoxyalkylene monoamine, JEFFAMINEM series manufactured by Sun Techno Chemical Co., Ltd. was used.
When describing these compounds below, they are simply M-600, M-1000, M-2005 and M-20, respectively.
Write 70.

[0032]

【table 1】 * 1 PO / EO is the ratio of propylene oxide and ethylene oxide contained in the molecule. * 2 Molecular weight is the molar weight average molecular weight.

Production Example 1 Melamine 0.67 mol (83.9 parts), 37% formaldehyde 3.33 mol (270.0 parts), water 171.0
Part was placed in a four-necked flask equipped with a stirrer, a thermometer, a reflux tube, and a dropping funnel, and mixed with stirring. After the temperature was raised to 65 ° C., the pH was adjusted to 11.1 with a 25% aqueous sodium hydroxide solution.
5, and reacted at 65 ° C. for 1 hour. Add urea 0.1
3 mol (8.0 parts) was added, and the mixture was reacted at 70 ° C. for 1 hour. Next, 214.8 parts of water are charged and 45
After cooling to 0 ° C., 0.2 mol of phenol (18.8
) Using a dropping funnel over 30 minutes. After completion of the charging, the reaction was carried out at 60 ° C. for 1 hour. Then, M-100
0.03 mol (33.3 parts) of 0 and 0.53 mol (55.4 parts) of anhydrous sodium bisulfite were added, and the mixture was stirred at 80 ° C. for 1 hour.
Allowed to react for hours. After cooling to 60 ° C, the pH was adjusted to 6.0 with 40% sulfuric acid, the temperature was raised to 65 ° C, and the reaction was performed. When the viscosity of the reaction solution reached 50 cp / 25 ° C, neutralization was performed with a 25% aqueous sodium hydroxide solution. To stop the reaction, 45c
A product with a p / 25 ° C. was obtained. The obtained product is referred to as a cocondensate 1, and its composition and physical property values are shown in Table 2.

Production Example 2 554.8 parts of water and 3.0 mol of 37% formaldehyde (243.2 parts) were added with a stirrer, a thermometer and a reflux pipe.
The mixture was placed in a one-necked flask and mixed with stirring. 0.67 mol of melamine (84.0 parts), urea 0.33
Mol (20.0 parts), sodium pyrosulfite 0.63 mol (120.3 parts), M-2070 0.03 mol (6
6.0 parts) was added with stirring. This was heated to 75 ° C., and after confirming that it became a transparent liquid, it was adjusted to pH 11 with a 25% aqueous sodium hydroxide solution and reacted at 75 ° C. for 2 hours. After confirming that free sulfite ions had disappeared, the mixture was cooled to 60 ° C. Next, p with 40% sulfuric acid
The reaction mixture was adjusted to H6.0 and the reaction was allowed to proceed at 60 ° C. When the viscosity of the reaction solution reached 50 cp / 25 ° C, the reaction was stopped by neutralizing with 25% aqueous sodium hydroxide solution to 45 cp / 25
C product was obtained. The obtained product is referred to as a cocondensate 2,
The composition and physical property values are shown in Table 2.

Production Example 3 553.1 parts of water and 3.33 mol (270.0 parts) of 37% formaldehyde were added to a 4 equipped with a stirrer, a thermometer and a reflux tube.
The mixture was placed in a one-necked flask and mixed with stirring. Melamine (1.0 mol, 127.2 parts) and M-600 (0.3 mol, 181.6 parts) are added to the flask under stirring. This was heated to 70 ° C., and after confirming that it became a transparent liquid, the pH was adjusted to 11 with 25% aqueous sodium hydroxide solution, and the mixture was reacted at 70 ° C. for 1 hour. Next, it was cooled to 55 ° C., and anhydrous sodium bisulfite 0.7 mol (73.5 parts)
Was added. Although the internal temperature increased by the addition of anhydrous sodium bisulfite, the temperature was further increased to 80 ° C. The reaction was continued at 80 ° C., and after confirming that free sulfite ions had disappeared, the mixture was cooled to 60 ° C. Next, p with 40% sulfuric acid
The reaction was proceeded at 60 ° C., and when the viscosity of the reaction solution reached 150 cp / 25 ° C., the reaction was neutralized with a 25% aqueous sodium hydroxide solution to stop the reaction.
A product at 25 ° C. was obtained. The obtained product is referred to as a cocondensate 3, and its composition and physical property values are shown in Table 2.

Production Examples 4 to 5 In the same manner as in Production Example 1, the composition of the compound was changed as shown in Table 2 to attempt condensation. As a result, co-condensate 4-5
I got The composition and physical property values are shown in Table 2.

Production Examples 6 to 7 Condensation was tried in the same manner as in Production Example 2 while changing the composition of the compound as shown in Table 2. As a result, the cocondensate 6-7
I got The composition and physical property values are shown in Table 2.

Production Examples 8 to 10 By the same method as in Production Example 3, the composition of the compound was changed as shown in Table 2 to attempt condensation. As a result, the cocondensate 8-1
0 was obtained. The composition and physical property values are shown in Table 2.

Production Examples 11 to 13 Condensation was tried in the same manner as in Production Example 1 while changing the composition of the compound as shown in Table 2. As a result, the cocondensates 11 to 11
13 was obtained. The composition and physical property values are shown in Table 2.

[0040]

[Table 2]

[0041]

[Table 3] The concrete test formulations are shown below. Materials for concrete kneading Cement: Three kinds of ordinary Portland cement (Mitsubishi Materials Corporation, Chichibu Onoda Corporation, Tokuyama Corporation)
Specific gravity = 3.16 Fine aggregate: Weathered granite sand from Irino, Kawachi-cho, Kamo-gun, Hiroshima Prefecture
Specific gravity = 2.57 Coarse aggregate: Hard sandstone crushed stone from ishiishi-shaped wall stone in Shimonoseki-shi, Yamaguchi Prefecture Crushed stone 5: Crushed stone 6 = 1: 1: 1 Specific gravity = 2.69

Example 1 Using a 50-liter forced twin-screw concrete mixer, based on the composition shown in Table 3, cement, coarse aggregate, and the mixture obtained in Production Example 1 were mixed so that the kneaded amount was 40 liters. The condensate 1 and water were added, and the mixture was kneaded for 90 seconds, and further coarse aggregate was added and kneaded for 3 minutes. A fluidized concrete having a slump of 18 cm and an air content of 3% was prepared. In order to reach the target air volume, if the entrained air volume is insufficient, use the air entrainer Vinsol manufactured by Yamamune Chemical Co., Ltd.
When the amount of air was excessive, it was adjusted using Dereklite 850 manufactured by Hokucon Sangyo Co., Ltd. as an antifoaming agent. After kneading, slump and slump flow with time were measured every 30 minutes until 90 minutes later. The compressive strength is φ10
Cylinder type test piece of 20 cm in height and 20 cm in height was prepared, and 7 days a day
The measurement was performed on the 28th day. Regarding the material separation resistance, the degree of movement of the aggregate during slump flow measurement was visually observed, and relative evaluations of ◎, 、, Δ, and × were made. The slump, the amount of air, the setting time, the method for measuring the compressive strength, and the method for producing the sample for compressive strength were all in accordance with Japanese Industrial Standards (JLS-A6204). Table 4 shows the results
Shown in

Examples 2 to 10 The same operations as in Example 1 were performed except that the cocondensates 2 to 10 were used. Table 4 shows the results.

Comparative Examples 1 to 3 The same operations as in Example 1 were carried out except that the cocondensates 11 to 13 were used. Table 4 shows the results.

Comparative Example 4 M-1000 was simply blended with the cocondensate 11 used in Comparative Example 1 so as to have the same composition as the cocondensate 1. Using this, the same operation as in Example 1 was performed. Table 4 shows the results.

Comparative Examples 5 to 9 As a water-reducing agent for comparison and control, a commercially available high-performance water-reducing agent Melflow 40 (Mitsui Toatsu Chemicals, Inc .: melamine type),
Mighty 150 (Kao Corporation: naphthalene type), Palic FP200U (Fujisawa Pharmaceutical Co., Ltd .: aminosulfonic acid type), sustained release type Mighty 2000WH which is a high performance AE water reducing agent (Kao Corporation: naphthalene type + The same operation as in Example 1 was performed using Tupole HP-8 (Takemoto Oil & Fats Co., Ltd .: polycarboxylic acid system). Table 4 shows the results.

[0047]

[Table 4]

[0048]

As is clear from the examples and comparative examples, the cement admixture obtained according to the present invention shows a high flow effect at a low addition amount and a residual flow as compared with the existing cement water reducing agent. It has the characteristics of high rate and excellent daily strength. That is, it has a high initial fluidity and an excellent slump retention property for a cement composition such as mortar and concrete without causing a hardening delay. Furthermore, the material separation resistance is also excellent. Therefore, when the cement admixture obtained by the present invention is used for civil engineering and construction-related works, workability can be significantly improved.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihiko Tomita 7-1-1, Hikoshimasako-cho, Shimonoseki-shi, Yamaguchi Pref.

Claims (7)

[Claims] 1. A cement comprising a polyoxyalkylene monoamine (A), a polyoxyalkylene monoamine, a formaldehyde co-condensable monomer (B), a sulfone group-forming compound (C) and a co-condensate containing formaldehyde. Admixture. 2. The cement admixture according to claim 1, wherein the polyoxyalkylene monoamine (A) is represented by the following general formula (1). Formula _{(l) R 1 O- (AO} ) m (BO) n -R 2 -NH 2 where, _{R 1:} an alkyl group having 1 to 5 carbon atoms R _2: alkylene group having 1 to 5 carbon atoms AO, BO: an oxyalkylene group having 2 to 5 carbon atoms AO and BO are block and / or random m, n: an integer of 0 to 100. However, 100 ≧ m + n ≧ 4 3. The monomer (B) capable of co-condensing polyoxyalkylene monoamine with formaldehyde is one or more selected from the group consisting of melamine or its derivative, phenol or its derivative, urea or its derivative. The cement admixture according to claim 1, which is a compound of 1. 4. A compound (C) which forms a sulfone group
The cement admixture according to claim 1, wherein the cement admixture comprises one or more compounds selected from the group consisting of sodium sulfite, sodium bisulfite, sodium pyrosulfite, fuming sulfuric acid, and sulfur dioxide. 5. The cement admixture according to claim 3, wherein melamine or a derivative thereof is represented by the following general formula (11). General formula (11) 6. The cement admixture according to claim 3, wherein the phenol or its derivative is represented by the following general formula (111). General formula (Ill) 7. The cement admixture according to claim 3, wherein urea or a derivative thereof is represented by the following general formula (IV). General formula (LV)