KR100462452B1 - method of manufacturing the concrete admixture - Google Patents

Abstract

In the method for producing a concrete admixture, a mixture of methoxy polyethylene glycol, an acryl-based compound, an amine-based compound having a nitrogen group, and a solvent is mixed and reacted so that the terminal hydroxyl group of the methoxy polyethylene glycol is an acryl-based compound and an amine-based compound. To form intermediates substituted with compounds. Thereafter, the polymer compound in which the intermediate, the acrylic compound, and the amine compound are polymerized is graft polymerized under the addition of lignin to prepare a concrete admixture including the modified polycarboxylic acid mixture copolymer. The concrete admixture can improve the concrete workability and dispersibility and can prevent the generation of bubbles.

Description

Method of manufacturing the concrete admixture

The present invention relates to a method for producing a dispersant, and more particularly, to a method for producing a admixture for concrete.

Concrete is composed of cement, sand and gravel as binders for hydroponic reactions, and due to the characteristics of cement, it is necessary to use much more water than hydroponic reactions for smooth workability. However, the increase in the number of uses acts as a defect in the concrete structure after curing, resulting in a decrease in compressive strength. Accordingly, efforts have been made to reduce the number of used concretes, and cement dispersants using early lignin sulfur oxides have been used, and naphthalene sulfur oxides and melamine sulfur oxides have been developed and widely used.

They act on the particles of cement to increase the distance between the particles, thereby lowering the viscosity of the concrete. The slump test is used to measure the decrease in the viscosity of concrete, and the most commonly used is 12cm-15cm. When the size of the slump is 22cm or more, the separation between layers due to the difference in specific gravity between cement particles and aggregates May occur. In addition, the reaction of the cement is made from the moment of contact with the water, the use of the slump changes during use or moving by transport equipment, such as trucks may be impossible to use. The type and specification of such cement dispersant is defined as KSF 2560 concrete chemical admixture.

As conventional concrete admixtures, lignin-based dispersants, naphthalene sulfonic acids, melamine resin sulfonic acids, and the like are known. However, in the manufacture of low-viscosity concrete for the high-rise or the realization of ultra-high strength, they cause problems such as sudden decrease of slump, sedimentation of aggregates due to increase of usage, delay of condensation. In order to overcome this problem, recently, concrete admixtures having excellent slump holding force without sedimentation of aggregates have been newly developed.

Examples of documents that propose a solution to solve the problems of the conventional admixture are as follows.

U.S. Patent No. 473406 discloses a high performance fluidizing agent consisting of a copolymer of acrylic or methacrylic acid and hydroxy alkylacrylate or methacrylate.

Korean Patent Publication No. 1999-006835 discloses that a polycarboxylic acid-based admixture composed of polyalkylene glycol (meth) acrylate and (meth) acrylic acid exhibits cement dispersion performance and high slump retention performance.

Korean Patent Publication No. 1998-085570 discloses a concrete admixture using polyoxypropylene or polyoxyethylene for acrylic acids using 2,2'-azobisisobutylonitrile, which is a useful initiator in the presence of isopropyl alcohol. A method is disclosed.

Korean Patent Publication No. 1998-064529 discloses a process for preparing cement admixtures comprising monomers based on unsaturated polyalkylene glycol ethers and maleic acid.

However, the admixture disclosed above causes actual air entrainment when applied to concrete, and has a problem of high price compared to conventional lignin and naphthalene-based admixtures.

U.S. Patent No. 5047087 discloses a low cost, high performance fluidizing agent copolymer composition which solves the problem of excessive air entrainment and admixtures including acrylic acid, acrylic acid esters and third polymerizable vinyl monomers. A method of addition is disclosed.

However, when the antifoaming agent is added after the method described above, the specific gravity of the admixture is generally 1.0 or more, whereas the antifoaming agent is 1.0 or less, and the specific gravity of the antifoaming agent is 1.0 or less, and it is not dissolved in water. The process is complicated because it is difficult to obtain an integrated anti-foaming dispersant having a defoaming property, and when the cement slurry is mixed, the water-sensitive dispersant and the antifoaming agent must be added separately. In addition, when the antifoaming agent is added, there is a problem of poor workability.

An object of the present invention for solving the above problems is to provide a method for producing a concrete admixture that is excellent in concrete workability, and can prevent the generation of bubbles.

In the production method of the present invention according to an embodiment for achieving the above object, a mixture of methoxy polyethylene glycol, an acrylic compound, an amine compound having a nitrogen group and a solvent is mixed and reacted The hydroxyl group of the oxy polyethylene glycol forms an intermediate substituted with an acrylic compound and an amine compound. Thereafter, the polymer compound formed by polymerizing the acrylic compound and the amine compound and the intermediate are graft polymerized under the addition of lignin to prepare a concrete admixture including a modified polycarboxylic acid mixture copolymer.

The concrete admixture of the present invention prepared by the above method can not only improve the dispersion of concrete but also impart high concrete slump retention characteristics. In addition, the concrete admixture of the present invention is relatively inexpensive than the conventional admixture that can suppress the generation of bubbles during concrete production, it is possible to increase the air ductility and defoaming.

Hereinafter, the manufacturing method of the concrete admixture containing the modified polycarboxylic acid mixture type copolymer of this invention is demonstrated.

According to the present invention, a method for preparing a concrete admixture may be performed by first reacting a mixture including a methoxy polyethylene glycol, an acryl-based compound, an amine-based compound having a nitrogen group, and a solvent in a first step. The hydroxyl group (OH) at the terminal forms an intermediate in the form substituted with the acryl-based compound and the amine-based compound.

At this time, it is preferable to further add sulfuric acid having a concentration of 98% as an acid catalyst and hydroquinone as a polymerization inhibitor in the esterification step. The first degree of reaction can be determined by confirming the formation of methoxy polyethylene glycol methacrylate as a monomer by applying liquid chromatography. After the completion of the first reaction, a process of removing the solvent and a second process of washing and neutralizing the resultant are further performed.

Subsequently, in the reaction tank to which the initiator is added in the second step, the polymer compound formed by polymerizing the acrylic compound and the amine compound and the intermediate obtained in the first reaction are graft polymerized under the addition of lignin to modify the modified polycar. A concrete admixture comprising an acid mixture copolymer is prepared.

More specifically, the second step, the intermediate and water formed in the first reaction of the first step is uniformly stirred, and simultaneously the first dropping and the second dropping solution to the reactor maintained at 70 to 90 ℃ It was dripped for about 2 hours or more, and when the dropping was completed, the reaction was completed by maintaining the reaction temperature for 3 hours. Thereafter, the resultant is neutralized using sodium hydroxide to prepare a concrete admixture including a modified polycarboxylic acid mixture copolymer having a polymer content of 35 to 45% and a molecular weight of 27000 to 39500.

Here, the modified polycarboxylic acid mixture copolymer is formed by graft polymerization of the intermediate in the side chain of each node of the main chain of the polymerized compound. It is preferable to add lignin during the esterification reaction or the graft polymerization reaction for preparing the concrete admixture.

Examples of the acryl-based compound include acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. Examples of the amine compound include acrylamide, isobutylylamine, and polyisobutylamine.

More specifically, when the intermediate is formed in the first reaction, the acrylic compound is used in an amount of 15 to 150 parts by weight based on 150 parts by weight of the methoxy polyethylene glycol, an amine compound is used in an amount of 0.5 to 10 parts by weight, and the solvent is 50 to 120 parts by weight is used.

In addition, when the modified polycarboxylic acid mixture copolymer is formed by a graft polymerization reaction, the acrylic compound is used in an amount of 10 to 20 parts by weight based on the methoxy polyethylene glycol 150, and the amine compound is 2 to 8 parts by weight. Parts are used, and 0.5 to 1.5 parts by weight is used for opening.

The addition of the lignin can be injected during the initial and the reaction of the graft polymerization reaction, the amount of the lignin is used 1.5 to 75 parts by weight, preferably 2 to 30 parts by weight based on 150 parts by weight of the methoxy polyethylene glycol. Here, when the amount of the lignin used exceeds 76 parts by weight, a problem occurs that the strength of the concrete decreases. The first reaction is an esterification reaction.

The concrete admixture of the present invention prepared by the above-described method can not only improve the dispersion of concrete than conventional concrete admixtures but also impart high concrete slump maintenance characteristics. In addition, it is possible to suppress the generation of bubbles in the production of concrete at a relatively low cost, and to increase the air deterioration and defoaming. The methylacrylic acid included in the admixture forms a carboxyl group when hydrolyzed in an alkaline atmosphere, and the amine compound and lignin adhere to or partially crosslink with the functional group to strengthen the binding force.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following Examples are intended to illustrate the present invention, but are not limited thereto.

Example 1

150 g of methoxy polyethylene glycol, 30 g of methacrylic acid as an acrylic compound, 1 g of isobutylamine having a nitrogen group as an amine compound, and 80 g of benzene as a solvent were introduced into a glass reactor equipped with a thermometer, a stirrer, a product water separator, and a reflux condenser. Stir evenly. At this time, 0.5 g of 98% sulfuric acid as an acid catalyst and 0.2 g of hydroquinone as a polymerization inhibitor were further added, followed by stirring at 80 ° C. to carry out an esterification reaction. The degree of esterification reaction is terminated after confirming that the monomer methoxy polyethylene glycol methacrylate is formed by applying liquid chromatography. Subsequently, after the reaction type, the benzene solvent applied in the esterification reaction was removed, followed by washing and neutralizing sulfuric acid as an acid catalyst, thereby forming an intermediate in which the terminal hydroxyl group of the methoxy polyethylene glycol was substituted with an acrylic compound and an amine compound. Pure water was then added to obtain an intermediate containing 30% water.

Subsequently, 60 g of intermediate and 40 g of pure water were added to the reactor, followed by stirring while maintaining the reaction temperature at 80 degrees. Subsequently, a first dropping solution containing 1 g of methacrylic acid, 5 g of acrylamine, and 3 g of lignin, and a second dropping solution of 1 g of Potassisium persulfate, an initiator, dissolved in 40 g of pure water were added to a reactor where stirring was performed. At the same time, it was dripped for about 3 hours. After the completion of the accumulation, the reaction was completed by maintaining the reaction temperature at 80 ° C. for 3 hours. Subsequently, the resultant was infused with sodium hydroxide to maintain a neutral pH to form a concrete admixture including the modified polycarboxylic acid mixture copolymer. The copolymer has a polymer content of about 40% and a molecular weight of about 35000.

Example 2

A concrete admixture was prepared in the same manner as in Example 1, except that 5 g of acryl amine was used instead of 1 g of isobutylamine used in the esterification reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 28900.

Example 3

A concrete admixture was prepared in the same manner as in Example 1, except that 2 g of polyisobutyl amine was used instead of 1 g of isobutyl amine used in the esterification reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 31500.

Example 4

A concrete admixture was prepared in the same manner as in Example 1, except that 2 g of acrylamide was used instead of 1 g of isobutylamine used in the esterification reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 29000.

Example 5

A concrete admixture was prepared in the same manner as in Example 1, except that 3 g of isobutylamine was used instead of 1 g of isobutylamine used in the esterification reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 29700.

Example 6

A concrete admixture was prepared in the same manner as in Example 1, except that 5 g of isobutylamine was used instead of 1 g of isobutylamine used in the esterification reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 27800.

Example 7

A concrete admixture was prepared in the same manner as in Example 1, except that 2 g of polyisobutylamine was used instead of 5 g of acrylamine used in the graft polymerization reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 39500.

Example 8

A concrete admixture was prepared in the same manner as in Example 1, except that 2 g of acrylamide was used instead of 5 g of acrylamine used in the graft polymerization reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 28900.

Example 9

A concrete admixture was prepared in the same manner as in Example 1, except that 3 g of isobutylamine was used instead of 5 g of acrylamine used in the graft polymerization reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 31700.

Example 10

A concrete admixture was prepared in the same manner as in Example 1, except that 5 g of isobutylamine was used instead of 5 g of acrylamine used in the graft polymerization reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 32800.

Example 11

A concrete admixture was prepared in the same manner as in Example 1, except that 5 g of lignin was used instead of 3 g of lignin used in the graft polymerization reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 32000.

Example 12

A concrete admixture was prepared in the same manner as in Example 1, except that 25 g of lignin was used instead of 3 g of lignin used in the graft polymerization reaction. The copolymer has a polymer content of about 50% and a molecular weight of about 31500.

Example 13

A concrete admixture was prepared in the same manner as in Example 1, except that 75 g of lignin was used instead of 3 g of lignin used in the graft polymerization reaction. The copolymer has a polymer content of about 60% and a molecular weight of about 30000.

Comparative Example 1

A concrete admixture was prepared in the same manner as in Example 1, without using the isobutylamine used in the esterification reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 23100.

Comparative Example 2

The concrete admixture was prepared in the same manner as in Example 1, without using the acrylamine used in the graft polymerization reaction. The copolymer has a polymer content of about 40% and a molecular weight of about 28100.

Comparative Example 3

A concrete admixture was prepared in the same manner as in Example 1, except that 150 g of lignin was used instead of 3 g of lignin used in the graft polymerization reaction. The copolymer has a polymer content of about 70% and a molecular weight of about 2600.

Experimental Example 1

The concrete admixtures obtained in Examples 1 to 13 and Comparative Examples 1 to 3 were respectively combined with concrete based on the injected amount of each component shown in Table 1, and then the degree of bubble generation of the concrete was measured. The results are shown in Table 2 below.

division W / C S / A W C S G L-PC Unit (g) 34.8 41.5 181 520 661 932 6.24

W: Water, C: Concrete, S: Sand, A: Aggregate, G: Gravel, L-PC: Concrete Admixture

division Experiment result division Experiment result Example 1 Bubble generation (X) Example 9 Bubble generation (X) Example 2 Bubble generation (X) Example 10 Bubble generation (X) Example 3 Bubble generation (X) Example 11 Bubble generation (X) Example 4 Bubble generation (X) Example 12 Bubble generation (X) Example 5 Bubble generation (X) Example 13 Bubble generation (X) Example 6 Bubble generation (X) Comparative Example 1 Bubble generation (0) Example 7 Bubble generation (X) Comparative Example 2 Bubble generation (0) Example 8 Bubble generation (X) Comparative Example 3 Bubble generation (0)

Experimental Example 2

The concrete admixtures obtained in Examples 1, 11, 12, and 13 and Comparative Example 3, respectively, were blended with concrete based on the injected amount of each component shown in Table 1, and then physical properties were evaluated by the following concrete test method. The results are shown in Table 3 below.

division League addition amount (g) Polymer molecular weight Slump (cm) V-Lot (seconds) Compressive Strength (Kg / cm2) Early 60 minutes Early 60 minutes 3 (10/10) 7 (10/14) 28 (11/04) Example 1 3 35000 59 × 61 55 × 54 7 6 479, 482 472, 510 456, 490 Example 11 5 32000 59 × 61 55 × 55 7 9 479, 482 472, 510 456, 460 Example 12 25 31500 59 × 61 56 × 51 12 15 442, 422 452, 460 436, 440 Example 13 75 30000 59 × 61 51 × 50 15 16 429, 482 472, 510 456, 460 Comparative Example 3 150 26000 39 × 31 B 30 B 379, 382 372, 310 356, 360

B: poor measurement

Concrete test method

1, The slump experiment was carried out by the method of KS F 2402. The concrete mixture was injected into a constant cone-shaped container and discharged to the bottom. .

2, Air content test is to measure the amount of entrained air over time by applying the air content test method KS F 2421 by the pressure method of the hard concrete.

3, compressive strength is measured by the KS F 2405 method to measure the strength of 3 days, 7 days 28 days.

4, V-Lot time measures the time that the entire concrete flows out by putting the concrete mixture in a certain container and opening the bottom opening.

The concrete admixture of the present invention prepared by the above method can not only improve the dispersion of concrete but also impart high concrete slump retention characteristics. In addition, the concrete admixture of the present invention is relatively inexpensive than the conventional admixture that can suppress the generation of bubbles during concrete production, it is possible to increase the air ductility and defoaming.

Claims (10)

(a) an intermediate in which a hydroxy polyethylene glycol, an acrylic compound, an amine compound having a nitrogen group, and a mixture of a solvent are mixed and reacted so that the terminal hydroxyl group of the methoxy polyethylene glycol is substituted with an acrylic compound and an amine compound Forming a; And (b) preparing a modified polycarboxylic acid mixture copolymer by graft polymerization of the intermediate compound formed in step (a) with the polymer compound polymerized with the amine compound and the amine compound under the addition of lignin; Concrete admixture manufacturing method comprising a. The method of claim 1, wherein when the intermediate is formed, 15 to 100 parts by weight of the acrylic compound, 0.5 to 10 parts by weight of the amine compound, and 50 to 120 parts by weight of the solvent are used based on 150 parts by weight of the methoxy polyethylene glycol. Process for preparing admixtures. The method of claim 1, wherein lignin, an acid catalyst and a polymerization inhibitor are further added during the reaction process. The method of claim 1, wherein after the step (a), a solvent removal, washing, and neutralization processes included in the resultant are performed. The method of claim 1, wherein an initiator is further added during the graft polymerization process. The method of claim 5, wherein the lignin is 1.5 to 75 parts by weight based on 150 parts by weight of the methoxy polyethylene glycol. The method of claim 1, wherein after the step (b), the neutralization process is carried out. The method of claim 1, wherein the acrylic compound comprises at least one selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. The method of claim 1, wherein the amine compound includes any one selected from the group consisting of acrylamide, isobutyl amine, and polyisobutyl amine. The method of claim 1, wherein the modified polycarboxylic acid-based mixture copolymer has a polymer content of 35 to 45%, and has a molecular weight of 27000 to 39500.