JP2000327388A - Cement additive and cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cement additive which is simply producible and is usable for general-purposive, and also to provide a cement composition using the same. SOLUTION: This cement additive is obtained from (A) a compound having two or more amino groups, (B) a formyl group-containing carboxylic acid-based compound and (C) other introducible compound, if necessary, as raw materials and comprises a polymer obtained by simultaneously polymerizing at least part of the compound A with at least part of the compound B as an essential ingredient.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a cement additive and a cement composition using the same.

[0002]

2. Description of the Related Art In civil engineering and construction sites, cement is frequently used. Cement paste obtained by adding water to cement, mortar obtained by mixing sand as fine aggregate, and concrete obtained by mixing pebble as coarse aggregate are also used. Is widely used for structural materials, civil engineering, fire-resistant walls, etc., and its usage is large. In these cement pastes, mortars, and concretes, the hydration reaction between cement and water generates strength through coagulation and hardening, so that the workability decreases with the lapse of time after the addition of water. On the other hand, if the unit water content in the ready-mixed concrete is increased to improve workability, the strength of concrete or the like is reduced. Therefore, in order to improve the workability at the time of construction of fresh concrete and to improve the durability of concrete, the workability is improved without increasing the water content,
There is a demand for a cement additive used to reduce the amount of water and maintain workability. In particular, since the early deterioration of concrete structures has become a social problem, there has been a strong demand for reducing the unit water content in concrete to improve its workability and durability. Technological innovations are taking place for cement additives that have significant impact.

[0003] Various cement additives have been developed. Among them, polyalkylene glycol mono (meth) acrylate monomers and (meth) acrylate monomers described in JP-B-59-18338 are disclosed. And a copolymer obtained by polymerizing an unsaturated polyalkylene glycol ether-based monomer and a maleic acid-based monomer described in JP-A-10-236858 at a specific ratio. The coalescence is particularly excellent in dispersion performance.

According to "Development of concrete admixtures and the latest technology (CMC)", polycarboxylic acid-based water reducing agents include not only the electric force of the carboxyl group which is the main chain but also the polychain which is the side chain. It shows an excellent water reducing effect due to the steric effect of the alkylene glycol chain. As described above, a polyalkylene glycol chain or a carboxyl group alone cannot provide excellent water reducing performance, and it is important for a conventional water reducing agent to have both a polyalkylene glycol chain and a carboxyl group. However, such a water reducing agent is currently used only for special applications such as high-strength concrete and high-fluidity concrete because the production method is complicated and the production cost is increased accordingly. Therefore, there is a demand for the development of a general-purpose cement additive having even better performance with the aim of improving workability and physical properties.

[0005] Japanese Patent Publication No. 1-53222 discloses a cement dispersant comprising a modified amino resin having a carboxylic acid group introduced into a co-condensation resin of a urea compound and an aldehyde. However, in order to obtain this cement dispersant, it is necessary to once modify the co-condensation resin with a carboxylic acid to introduce a carboxyl group, so that the production process is complicated and can also be used for general purposes. It could not be a cement additive.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cement additive which can be used for a general purpose without complicated production steps and a cement composition using the same.

[0007]

In order to solve the above-mentioned problems, in the present invention, a compound having two or more amino groups (A), a carboxylic acid compound containing a formyl group (B), and optionally a Additive which is obtained by simultaneously polymerizing at least a part of the compound (A) and at least a part of the compound (B) using the other compound (C) which can be introduced as a raw material. I will provide a.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The compound (A) is a compound having two or more amino groups (-NH ₂ groups). And melamine, melamine monosulfonic acid, and the like. Of these, urea and thiourea are preferred, and urea is particularly preferred.

The compound (B) has a formyl group (-CHO)
Group) -containing carboxylic acid compounds. The polymerization reaction proceeds by the dehydration addition condensation reaction of the formyl group of the compound (B) and the amino group of the compound (A) at a molar ratio of 1: 2.
Examples of the formyl group-containing carboxylic acid compound of the compound (B) include a formyl group-containing carboxylic acid, a salt thereof, and a compound which can be converted to a formyl group-containing carboxylic acid or a salt thereof by hydrolysis. Examples of the formyl group-containing carboxylic acid include glyoxylic acid, formyl acetic acid, formyl propionic acid, and formyl butyric acid. Examples of the salt of the formyl group-containing carboxylic acid include monovalent metal salts (Na, K, Li, etc.), divalent metal salts (Ca, Mg, etc.), ammonium salts, and organic amine salts of these formyl group-containing carboxylic acids. Can be Examples of the compound which can be converted into a formyl group-containing carboxylic acid or a salt thereof by hydrolysis include esters and amides of a formyl group-containing carboxylic acid, and an alkyl ester having 1 to 4 carbon atoms and an alkylamide having 1 to 4 carbon atoms are preferable. As the compound (B), esters and amides of a formyl group-containing carboxylic acid are preferable because they are more stable than formyl group-containing carboxylic acids and salts thereof.
Among them, methyl glyoxylate and ethyl glyoxylate are preferable, and methyl glyoxylate is particularly preferable.

The compound (C) is another compound that can be introduced. Upon polymerization of compound (A) and compound (B),
The compound may be a copolymerizable compound or a compound entering the polymer terminal. Specific examples include ammonia; a compound having one amino group; and aldehydes having no carboxyl group. Examples of the compound having one amino group include glycine, alanine, leucine, aspartic acid, lysine, arginine, phenylalanine, ethanolamine, and methoxypolyethylene glycol monoamine. Examples of the aldehyde having no carboxyl group include formaldehyde and acetaldehyde. The compound having two or more amino groups is the compound (A), and the aldehyde having a carboxyl group is the compound (B). The amount of the compounds (A) to (C) used in the present invention is, in molar ratio, compound (A) / compound (B) / compound (C) = 1 / 0.1 to 1
The range of 0/0 to 0.9 is preferable, and 1 / 0.6 to 2.0
/0-0.5 is more preferable, and 1 / 0.8-1.
The range of 2/0 to 0.3 is more preferable. That is, the used amount of the compound (C) is 0 or the compound (A)
Is preferably less than the amount used. If the amount of the compound (C) used is greater than or equal to the amount of the compound (A) used, the hydrophilicity and the polymerizability are reduced, which is not preferable. Also,
When formaldehyde or the like is used as the compound (C), its use poses a problem in environmental hygiene.

In the present invention, in the polymerization reaction using the compounds (A) to (C) as raw materials, it is necessary to simultaneously polymerize at least a part of the compound (A) and at least a part of the compound (B). . Here, "simultaneously" means that the reaction is not a two-stage reaction in which a polymer is further reacted and then post-modified as in Japanese Patent Publication No. 1-53222. It means that at least a part of the compound (A) and at least a part of the compound (B) as a monomer are simultaneously subjected to a polymerization reaction. In the present invention, at least a part of each of the compounds (A) and (B) may be polymerized at the same time, but the compounds (A) and (B)
It is preferable that 1 mol% or more of the compounds be simultaneously polymerized, more preferably 10 mol% or more, further preferably 50 mol% or more, and most preferably 100 mol%. As described above, at least a part of the compound (A) and at least a part of the compound (B) are simultaneously polymerized, whereby a carboxyl group can be introduced into the polymer in one step simultaneously with the polymerization. No post-denaturation as in the publication is necessary, and the manufacturing process is simplified.

The compound (C) is not particularly limited, but is preferably reacted simultaneously with the compounds (A) and (B) in order to simplify the production process. The polymerization method is not particularly limited, and a known polymerization method such as solution polymerization or bulk polymerization can be adopted. However, bulk polymerization is preferable because it is not necessary to remove the solvent after the reaction and the cost is advantageous.

The solvent used in the solution polymerization is not particularly limited, but is preferably a solvent that does not adversely affect the polymerization efficiency. Examples of such a solvent include n-butane, propane, benzene and cyclohexane. Hydrocarbon solvents such as methyl chloride, naphthalene, etc .; halogenated hydrocarbon solvents such as methyl chloride, methylene chloride, chloroform, carbon tetrachloride, trichloroethane; alcohol solvents such as propanol, butanol, isopropyl alcohol, isobutyl alcohol, isoamyl alcohol; Ether solvents such as ether, isopropyl ether and butyl ether; ketone solvents such as methyl ethyl ketone, ethyl butyl ketone and methyl isobutyl ketone; ester solvents such as methyl acetate, ethyl acetate, ethyl benzoate and ethyl lactate; , Acetic acid, propionic acid, etc .; and polyhydric alcohols such as (poly) ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monobutyl ether acetate, tetraethylene glycol, propylene glycol monobutyl ether and derivatives thereof; Can be mentioned,
One or more of these can be used.

The polymerization can be carried out batchwise or continuously. The polymerization temperature is preferably 50 ° C. or higher.
When performing bulk polymerization, more preferably 90 ° C or higher and 25 ° C or higher.
The temperature is 0 ° C or lower, more preferably 110 ° C or higher and 200 ° C or lower. When performing solution polymerization, the upper limit of the polymerization temperature varies depending on the type of the solvent used, but it is preferable to carry out the polymerization at 50 ° C. or higher and the boiling point of the solvent used or lower.

Since the polymerization reaction of the compounds (A) and (B) is a reaction that generates water by addition condensation, it is preferable to use a dehydration facility such as a water separation tube. The dehydrating solvent used at this time is not particularly limited as long as the generated water can be removed from the system. Examples of such a dehydrating solvent include aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane and n-hexane; aliphatic alcohols such as isopropyl alcohol; ester compounds such as ethyl acetate; ketones such as acetone and methyl ethyl ketone. And the like, and one or more of these can be used.

At the time of polymerization, a catalyst may be added. Such a catalyst is not particularly limited, and examples thereof include an acid catalyst such as sulfuric acid, paratoluenesulfonic acid, and methanesulfonic acid. After the completion of the polymerization reaction, in the case of solution polymerization, the solvent used is preferably separated and removed by a separation means such as evaporation.

The molecular weight of the polymer produced by the polymerization is not particularly limited, but in consideration of the performance as a cement dispersant, the number average molecular weight is preferably 200 or more, and more preferably 500 or more.
More preferably, it is not more than 100,000. When the obtained polymer is an acid ester or an acid amide, it may be used as a cement additive as it is, or may be hydrolyzed in advance and used as an acid or a salt thereof. When used as it is as a cement dispersant, it is considered that it is hydrolyzed by alkali in the cement composition to form a carboxyl group or a salt thereof.

[0018] The cement additive of the present invention contains the polymer obtained as described above as an essential component. The polymer may be used alone or in combination with another cement additive. Other cement additives that can be used in combination with the cement additive of the present invention include, for example, cement dispersants (eg, lignin sulfonates and derivatives thereof, oxycarboxylates, polyol derivatives, polyoxyethylene alkyl allyl ether derivatives, alkyl Formalin condensate of allyl sulfonate, formalin condensate of melamine sulfonate, polycarboxylic acid polymer compound, etc.),
Water reducer, AE water reducer, high performance AE water reducer, air entrainer,
Cement wetting agents, swelling agents, waterproofing agents, retarders, quick-setting agents, water-soluble polymeric substances, thickeners, flocculants, drying shrinkage reducing agents, strength enhancers, curing accelerators, defoamers, etc. Can be. Among these, it is preferable to use together with an air entraining agent or a high-performance AE water reducing agent. The reason for this is that both excellent cement water-reducing performance and moderate air entrainment can be achieved at the same time. Therefore, the cement additive of the present invention is particularly preferably used as a cement dispersant and a concrete water reducing agent.

Examples of the air entraining agent which can be preferably used in the present invention include soaps such as resin acid soaps represented by Vinsol; sulfates such as higher alcohol sulfates and polyoxyethylene alkyl ether sulfates; polyoxyethylene alkyls Ethers such as ether and polyoxyethylene alkyl phenyl ether; ester ethers such as polyoxyethylene sorbitan oleate; betaine which is an amphoteric surfactant; imidazoline betaine; and the like can be used.

The amount of the air entrainer used together with the cement additive of the present invention is 0.001 to 1.0 with respect to the cement.
wt%, more preferably 0.001 wt%.
5 to 0.1 wt%. The high-performance AE water reducing agent that can be preferably used in the present invention includes a polycarboxylic acid-based water reducing agent;
Examples thereof include naphthalene type; aminosulfonic acid type; melamine type and the like. Among these, it is particularly preferable to use a polycarboxylic acid type. As a polycarboxylic acid-based high-performance AE water reducing agent, a copolymer of polyethylene glycol monoallyl ether, a maleic acid-based monomer and a monomer copolymerizable with these monomers described in JP-B-58-38380 is used. Combined, polyalkylene glycol mono (meth) acrylate-based monomer, (meth) acrylate-based monomer and monomer copolymerizable with these monomers described in JP-B-59-18338. Copolymer, JP-A-5
Copolymer of ethylenically unsaturated compound and maleic anhydride disclosed in JP-A-43288, JP-A-10-2368
No. 58, a copolymer of an unsaturated polyalkylene glycol ether-based monomer and another monomer copolymerizable with a maleic acid-based monomer.

The amount of the high-performance AE water reducing agent used in combination with the cement additive of the present invention is 0.01 to 0.01% based on the cement.
It is preferably 1.0 wt%, more preferably 0.03 to 0.5 wt%. The cement additive of the present invention can be blended with general hydraulic cement. Therefore, early strength Portland cement, low heat-generating Portland cement, high iron oxide type Portland cement,
In addition to special Portland cement, such as white Portland cement, mixed with ordinary Portland cement, natural cement, Roman cement, hydraulic lime, lime mixed cement, mixed Portland cement, alumina cement, belite-rich cement, various mixed cement, etc. Can be.

The amount of the cement additive of the present invention varies depending on the purpose of use of the cement additive. When the cement additive of the present invention is used as a cement dispersant, it is 0.001 to 10 wt% in terms of solid content based on cement.
And more preferably 0.01 to 5 w
t%, more preferably 0.05 to 1.0 wt%. In the cement composition prepared by mixing the cement additive so as to satisfy the above range, for example, various preferable effects such as reduction of unit water amount, increase of concrete strength, and improvement of mortar or concrete durability, etc. Is brought.

The cement composition of the present invention comprises at least cement, water and the cement additive of the present invention. If water is added to the cement additive and cement of the present invention, a cement paste is obtained, and mortar and concrete can be prepared by blending sand with fine aggregate and pebbles as coarse aggregate. . There is no particular limitation on fine aggregates and coarse aggregates that can be added to these cement compositions, and it is possible to appropriately select and use many types of fine aggregates and coarse aggregates currently used. it can. Also, the amount of fine aggregate and coarse aggregate to be added to the cement composition is not particularly limited, and can be appropriately determined by those skilled in the art according to the materials used.

The amount of water contained in the cement composition of the present invention is such that the weight of water relative to the cement is 30 to 70 wt.
%, More preferably 50 to 60 w
t%. This is because the cement additive of the present invention is particularly excellent in water reducing effect, and exhibits sufficient cement dispersibility with a smaller amount of water than the conventional amount of water.

[0025]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. In the examples, “parts” and “%” are unless otherwise specified.
The terms “parts by weight” and “% by weight” are respectively represented.

In the following, the molecular weight was measured by GPC (gel permeation chromatography) under the following conditions. -Column: Two G3000PWXL (manufactured by Tosoh) in series-Column temperature: 35 ° C (temperature controlled in column oven)-Mobile phase: 34.5 disodium hydrogen phosphate dodecahydrate
g, 46.5 g of sodium dihydrogen phosphate dihydrate, weighed to 5000 g by adding pure water (ion-exchanged water), and filtered with a 0.45 micron membrane filter. min ・ Measurement sample ・ ・ ・ Aqueous solution diluted with mobile phase to 0.1% in terms of solid content ・ Injection volume ・ ・ ・ 40μl ・ Detector ・ ・ ・ UV 214nm Hitachi L-4000H U
V detector ・ Standard sample for calibration curve Sodium polyacrylate standard sample (Sowa Kagaku) PAA70K, PAA35K, PAA18K, PAA8
K, PAA5K, PAA4K, PAA3K, PAA2
K, PAA1K 1,2,3,4-butanetetracarboxylic acid (special grade of reagent) 1,2,3-propanetricarboxylic acid (special grade of reagent) ・ Procedure for preparing a calibration curve Is plotted on the vertical axis to create a cubic curve. However, for the molecular weight of the sodium polyacrylate standard sample,
The peak top molecular weight value in the catalog is used, and the molecular weight in terms of Na is used for the remaining two samples.

Calculation of molecular weight A sample to be measured is calculated using a software MAXIMA820J manufactured by Waters, and the molecular weight is determined. [Production Example 1] Unpurified methyl glyoxylate 3 was placed in a glass reactor equipped with a thermometer, a nitrogen gas inlet tube, and a cooling tube.
After adding 3.0 g and 22.5 g of urea and stirring well, the reactor was heated to keep the internal temperature at 130 ° C. After maintaining the temperature for about 1 hour, the reaction was completed by air cooling. After crushing 32.2 g of the obtained polymer finely, 214.9 g of water was obtained.
When g was added, it became cloudy. Therefore, while stirring, 30
35.0 g of a 3% aqueous sodium hydroxide solution was added to obtain a transparent and pale yellow aqueous solution of the polymer (A). The weight average molecular weight (Mw) of the obtained polymer (A) was 470, and the number average molecular weight (Mn) was 120. FIG. 1 shows a GPC chart of the polymer (A). [Examples 1 to 4 and Comparative Examples 1 and 2] (Mortar test) 400 parts of ordinary Portland cement manufactured by Chichibu Onoda Cement Co., Ltd. and 800 parts of Toyoura standard sand were mixed with a Hobart type mortar mixer (model number N-50, Tesco). 30
After kneading for 2 seconds, a predetermined amount of a cement additive shown in Table 1 was weighed, and 260 parts of a mixture diluted with water was added and kneaded for 3 minutes to obtain a cement composition (mortar). The obtained mortar was filled into a hollow cylinder with an inner diameter of 54 mm and a height of 50 mm placed on a horizontal table until it was worn out, and the cylinder was gently lifted vertically and then the major and minor axes of the mortar spread on the table were measured. The average value was taken as the mortar flow value. The larger this value is, the better the cement dispersibility is. In the evaluation of the mortar having a small amount of entrained air, the amount of entrained air in the mortar was adjusted using an AE (air entraining) agent (trade name “VINSOL” of Yamamune Co., Ltd.). The amount of air was calculated from the volume and weight of the obtained mortar and the specific gravity of the material used.
Table 1 shows the results.

[0028]

[Table 1]

As can be seen from the results of Comparative Example 1 and Comparative Example 2, the use of the AE agent "Vinsol" increases the amount of air and the flow value. When the air amount increases, the viscosity decreases and the fluidity of the cement increases, so that when the air amount is large, the cement dispersibility seems to be large. Therefore, the flow value was evaluated by adjusting the air amount, and the air amount was adjusted to 9 ± 2 vol% (Examples 1 to 4 and Comparative Example 2).

As is clear from Table 1, the mortar using the cement additive of the present invention has an increased flow value in a volume-dependent manner. Particularly, when 0.20 wt% or more is used, a good cement dispersion is obtained. The effect was shown.

[0031]

According to the present invention, it is possible to provide a cement additive which does not require complicated production steps, can be used for general purposes, and exhibits excellent cement dispersing performance. Therefore, the cement composition using the cement additive of the present invention is advantageous in terms of cost and exhibits excellent cement dispersibility.

[Brief description of the drawings]

FIG. 1 is a GPC chart of a polymer (A) obtained in Production Example 1 of Examples.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigeru Yamaguchi 5-8, Nishimitabicho, Suita-shi, Osaka Nippon Shokubai Co., Ltd. (72) Inventor Ken Kenta 5-8, Nishimitabicho, Suita-shi, Osaka F term in Nippon Shokubai (reference) 4G012 PB16 PB20 PC01 PC14 4J033 EA01 EA12 EA16 EA23 EA74 HA02

Claims (4)

[Claims] 1. A compound comprising a compound (A) having two or more amino groups, a carboxylic acid compound containing a formyl group (B), and another compound (C) which can be introduced as required as a starting material. A cement additive comprising, as an essential component, a polymer obtained by simultaneously polymerizing at least a part of (A) and at least a part of compound (B). 2. The cement additive according to claim 1, wherein the amount of the compound (C) used is 0 or less than the amount of the compound (A) used. 3. The cement according to claim 1, wherein urea is used as compound (A), methyl glyoxylate is used as compound (B), and a polymer obtained by bulk polymerization of raw materials is used as an essential component. Additive. 4. The method according to claim 1, wherein at least cement, water and
A cement composition comprising the cement additive according to any one of claims 1 to 3.