JP3265784B2 - Additive for cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to additives for cement. More specifically, the present invention relates to an additive for cement which has excellent anti-slump loss properties, has a large water reduction, and has low air entrainment and low setting retardation.

[0002]

2. Description of the Related Art Naphthalene sulfonic acid formaldehyde condensate, melamine sulfonic acid formaldehyde condensate, lignin sulfonic acid salt, polycarboxylic acid compound, etc. are used as water reducing agents as additives for cement compounds such as concrete and mortar. Have been. In recent years, there has been an increasing demand for high strength concrete, and it has become necessary to reduce the amount of water in the concrete composition. Accordingly, the use of the polycarboxylic acid-based compound in the water reducing agent has increased in many cases. However, water reducing agents of polycarboxylic acid compounds have problems such as high air entrainment and retardation of setting.

[0003]

The high air entrainment causes a decrease in the strength of concrete. The setting delay also makes the work inefficient. The present invention has low air entrainment, low setting retardation, and high water reduction,
The purpose was to provide an additive for cement having both low slump loss properties.

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a copolymer of a specific polyoxyalkylene derivative and maleic acid has a low air entrainment property and a low setting retardation property, and has a high property. The present inventors have found that they have both water reducing properties and low slump loss properties, and have completed the present invention. That is, the present invention provides (A) the following general formula [1] (R ¹ ) ₂ N (AO) _n R ² ... [1] (where R ¹ is a hydrocarbon group having 1 to 5 carbon atoms, and AO is An oxyalkylene group having 2 to 4 carbon atoms, n = 1 to 200, R
² represents an alkenyl group having 2 to 5 carbon atoms. In addition, 50 mol% or more of the oxyalkylene group is an oxyethylene group) and (ii) one or more compounds selected from maleic anhydride, maleic acid, and maleic acid salt. An object of the present invention is to provide an additive for cement containing a copolymer as a main component. Examples of the hydrocarbon group having 1 to 5 carbon atoms represented by R ¹ in the general formula [1] include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, an amyl group, and an isoamyl group. Etc. Examples of the oxyalkylene group having 2 to 4 carbon atoms represented by AO in the general formula [1] include an oxyethylene group, an oxypropylene group, an oxybutylene group, and an oxytetramethylene group. The reason that 50 mol% or more of the oxyalkylene group is limited to the oxyethylene group is that when the oxyethylene group is less than 50 mol%, the water solubility becomes insufficient and the water reduction is inferior. In the general formula [1], n is 1 to 200. If it is larger than 200, the viscosity becomes high, and the production becomes difficult. The alkenyl group having 2 to 5 carbon atoms represented by R ² in the general formula [1] includes a vinyl group, an allyl group, a methallyl group, a 3-butenyl group,
Examples include a pentenyl group and a 3-methyl-3-butenyl group.
Examples of the maleate 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 salts. Examples of the organic amine salt include methylamine salt, ethylamine salt, propylamine salt, butylamine salt, dimethylamine salt, diethylamine salt, aniline salt, ethylenediamine salt, propylenediamine salt, diethylenetriamine salt, monoethanolamine salt, diethanolamine salt, and triethanolamine. There are amine salts such as amine salts, monoisopropanolamine salts, diisopropanolamine salts, and triisopropanolamine salts. Preferred are alkali metal salts, ammonium salts and alkanolamine salts. The copolymer of the polyoxyalkylene derivative of the general formula [1] and the maleic acid is represented by the general formula [1]:
By copolymerizing a polyoxyalkylene derivative with one or more compounds selected from maleic anhydride, maleic acid and maleate using a peroxide initiator or an azo initiator, Can be easily obtained. At that time, a solvent such as benzene, toluene, and xylene can be used. Also, in an aqueous solution, the general formula [1]
Easily obtained by copolymerizing a polyoxyalkylene derivative of the above with one or more compounds selected from maleic anhydride, maleic acid and maleate using an initiator such as persulfate. Can be. Further, at the time of copolymerization, other copolymerizable components such as styrene and vinyl acetate can be mixed. The molar ratio at the time of copolymerization of the polyoxyalkylene derivative of the general formula [1] and maleic acid is 3: 7 to 7: 3, preferably 4: 7.
The ratio is from 6 to 6: 4, preferably about 1: 1. In the present invention, the polyoxyalkylene derivative of the general formula [1] is copolymerized with maleic anhydride, the obtained copolymer is hydrolyzed, and the obtained hydrolyzate is converted into a salt. Can also obtain the copolymer of the present invention. Further, the copolymer of the present invention can also be obtained by copolymerizing the polyoxyalkylene derivative of the general formula [1] with maleic acid, and converting the obtained copolymer into a salt. The additive concentration of the additive of the present invention is from 0.01 to 3% by weight, preferably from 0.04 to 1% by weight, based on the cement. The additives of the present invention include other additives such as naphthalene sulfonic acid formaldehyde condensate salt, melamine sulfonic acid formaldehyde condensate salt, and polycarboxylic acid compound, or an antifoaming agent, an air entrainer, a rust inhibitor, and a coagulation accelerator. Agents, setting retarders and the like.

[0005]

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. Production Example 1 1 with stirrer, thermometer, nitrogen blowing pipe, cooling pipe
300 g of an allyl etherified product of 11 mol of ethylene oxide adduct of dimethylamine in a four-necked liter flask
52 g of maleic anhydride, 10 g of ammonium persulfate, and 241 g of water were charged and reacted at 80 ° C. for 6 hours under a nitrogen stream to obtain an aqueous solution of a copolymer. Production Examples 2 to 10 The reaction was carried out in the same manner as in Production Example 1 except that the compound of the general formula [1] shown in Table 1 and the maleic acid were used in the ratio shown in Table 1, and an aqueous solution of the copolymer was obtained. I got Examples 1 to 10 Tests using a mortar were carried out using a copolymer of a polyoxyalkylene derivative of the general formula [1] shown in Table 1 and maleic acids. The composition and test conditions are shown below. Ingredients Water 180 g Cement 360 g Sand 1080 g Additive Amount shown in Table 2 Water / cement ratio 50.0% Take each of the above components in a mortar mixer, knead and mix for 3 minutes, take out, flow value (according to JIS R-5201) And the amount of air (by the unit volume weight method) and the setting time (according to JIS A-6204) were measured. Further, after 30 minutes and 60 minutes, the flow value and the air amount were measured. Table 2 shows the results.

[0006]

[Table 1]

[0007]

[Table 2]

Comparative Examples 1 to 5 The same tests as in Examples 1 to 10 were carried out using the following compounds as comparative examples. Table 2 shows the results. Comparative Example 1 Naphthalenesulfonic acid formaldehyde condensate sodium salt Comparative Example 2 Sodium salt of copolymer of diisobutylene and maleic anhydride Comparative Example 3 Copolymerization of polyoxyethylene (10 mol) monoallyl ether and sodium maleate Comparative Example 4 Copolymer of polyoxyethylene (11 mol) monoallyl monomethyl ether and maleic anhydride Comparative Example 5 No additive Only Comparative Example 5 had the following composition. Blending composition Water 225 g Cement 360 g Sand 1080 g Water / cement ratio 62.5% The product of the present invention has a smaller change over time (slump loss) of the flow value than Comparative Example 1. In the products of the present invention, Comparative Examples 2 to 4 have a smaller amount of air and a shorter setting time. The product of the present invention has higher strength than Comparative Example 5 because the amount of water in the composition is smaller than that of Comparative Example 5.

[0009]

The additive of the present invention contains a copolymer of a specific polyoxyalkylene derivative and maleic acid as a main component, so that when used in mortar, concrete, etc., the air entrainment property and the setting retardation property are reduced. It is low in water content and high in slump loss prevention.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-279083 (JP, A) JP-A-4-175254 (JP, A) JP-A-63-285142 (JP, A) JP-A-63-285 11557 (JP, A) JP-A-51-18732 (JP, A) JP-A-60-27638 (JP, A) JP-A-5-132347 (JP, A) JP-A-6-298556 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) C04B 24/26-24/32 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] (A) The following general formula [1] (R ¹ ) ₂ N (AO) _n R ² ... [1] (where R ¹ is a hydrocarbon group having 1 to 5 carbon atoms, and AO is An oxyalkylene group of the formulas 2 to 4, n = 1 to 200, R
² represents an alkenyl group having 2 to 5 carbon atoms. In addition, 50 mol% or more of the oxyalkylene group is an oxyethylene group) and (ii) one or more compounds selected from maleic anhydride, maleic acid, and maleic acid salt. Additive for cement mainly composed of copolymer.