JPH11199289A - Cement hardening retarder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a retarder having good function to retard the hardening of cement and not causing leaching by water, by blending a metallic citrate with a resin binder. SOLUTION: This retarder contains a metallic citrate of formula I (where each of M<1> -M<3> is a divalent metallic element but all of M<1> -M<3> are not the same), in particular magnesium.calcium citrate of formula II and a resin binder. The metallic citrate is preferably used by 15-50 pts.wt. based on 100 pts.wt. of the resin binder. The resin binder is usually dissolved in an org. solvent or water is used as a dispersive medium therefor. The resin binder is preferably a vinyl acetate resin emulsion and an emulsion consisting of the vinyl acetate resin and water in a weight ratio of 50:50 is most suitable. When the retarder is used, a concrete product with a good washed-out pattern is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement setting retarder for delaying setting of cement which is a component of concrete or the like.

[0002]

2. Description of the Related Art Conventionally, when a wash-out pattern is formed on a concrete surface to express a makeup, a sheet with a cement setting retarder layer cut into a predetermined pattern shape is attached to the surface of a mold, and concrete is placed in the mold. 2. Description of the Related Art After a material is poured and cured and cured, it is removed from a mold, and a portion of the concrete surface where the curing of cement is delayed is washed out with high-speed jet water to express makeup. Also,
Rather than cutting the sheet with the cement setting retarder layer as described above, the sheet was masked so as to have a predetermined pattern shape, the unmasked portion was brought into direct contact with the concrete surface, and the setting of the cement was delayed. It is also practiced to wash out parts and express makeup.

[0003] Materials for forming the cement setting retarder layer include organic setting retarders such as citric acid, glucoheptonic acid, gluconic acid, galactonic acid, tartaric acid, and malic acid, and inorganic setting retarders such as magnesium silicofluoride. And a resin binder are used. This cement setting retarder is awarded because it retards the setting time of concrete and can subsequently undergo an active hydration reaction, similar to ordinary plain concrete.

[0004]

However, since all of the above-mentioned cement setting retarders are water-soluble, they are eluted by rainwater or night dew when concrete is cast outdoors to express makeup. There is. And, due to this elution, the desired makeup expression cannot be performed,
High quality concrete products cannot be provided.
In addition, if it was affected by the weather, such as when the makeup expression was disturbed in rainy weather and the makeup expression was good in fine weather, we could not always provide high-quality products. As a result, the reliability of the worker is impaired, and thus the reliability of the manufacturer is impaired. On the other hand, in order to solve such a situation, it is conceivable to carry out the work only in fine weather, but this has a problem that the construction period becomes longer. Therefore, development of a cement setting retarder which is not eluted by water and has a good cement setting delay ability is desired.

[0005] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a cement setting retarder which has a good function of delaying the setting of cement and is not eluted by water.

[0006]

In order to achieve the above object, the cement setting retarder of the present invention contains a metal citrate represented by the following general formula (1) and a resin binder. Take the configuration.

[0007]

Embedded image

That is, the present inventors have conducted a series of studies on a cement setting retarder which has a setting retardation property of a cement and is not eluted by water. In the process, the present inventors have focused on citric acid, which is a good substance as a cement setting retarder, and came up with the idea of modifying this. As a result, the cement has a good ability to retard the setting and is not eluted by water,
The inventors have found the metal citrate represented by the general formula (1), and have reached the present invention. The metal citrate represented by the general formula (1) is insoluble in water, but is soluble in alkaline water. Therefore, when used for an alkaline concrete material, a cement setting retarder is used. It can elute and disperse in the concrete material to delay the hardening of certain parts.

Particularly, it is presumed that the use of magnesium calcium calcium citrate represented by the above formula (2) as the metal citrate is particularly favorable as a cement setting retarder.

[0010] Further, it has been found that when the above-mentioned metal citrate is blended in the above-mentioned specific ratio, cement hardening retarding ability is more effectively exhibited.

[0011]

Next, an embodiment of the present invention will be described.

The cement setting retarder of the present invention (hereinafter simply referred to as "retarder") contains a special metal citrate and a resin binder.

The above-mentioned special metal salt of citric acid is a compound represented by the following general formula (1), wherein a divalent metal element is bonded to a carboxyl group of citric acid. These metal citrates may be used alone or in combination of two or more.

[0014]

Embedded image

In the general formula (1), M ¹ , M ² and M
^{As the} divalent metal element represented by ³ , magnesium,
Calcium, zinc and the like.

Among the metal citrates represented by the above general formula (1), magnesium citrate represented by the following formula (2) is particularly preferable from the viewpoint of the precision of a pattern formed on a concrete product. -Calcium is preferred. That is,
This is because the amount of concrete removed by washing becomes appropriate, and there is no possibility that the concave portion of the pattern shape is too deep or too shallow. Then, the reproducibility of the pattern shape by washing out is particularly preferable.

[0017]

Embedded image

The magnesium / calcium citrate represented by the above formula (2) can be produced, for example, as follows. First, 1/2 mol of citric acid was added to a water bath (70
0 g). Then, basic magnesium carbonate [3MgCO ₃ .Mg (OH) ₂ .3H ₂ O] 1/1
6 mol is added in a water bath and reacted. Subsequently, the temperature of the water bath is raised to about 60 ° C., and calcium carbonate having substantially the same mole as citric acid is gradually added into the water bath. After the addition,
Stir until the generation of carbon dioxide gas is almost stopped (for example, 7
0 ° C. × 4 hours). Thereafter, the temperature is further increased and stirred (for example, 80 ° C. × 30 minutes) to complete the reaction. Then, a precipitate is obtained by filtering the reaction solution obtained in this manner, and the precipitate is dried.
And magnesium calcium citrate represented by the formula: In the case of this synthesis, magnesium / calcium citrate represented by the following formula (3) is also obtained, but it is presumed that magnesium / calcium citrate represented by the above formula (2) has a higher cement setting delay ability. Is done.

[0019]

Embedded image

The analysis of the metal citrate represented by the general formula (1) can be performed by a combination of infrared spectroscopy (IR), elemental analysis, and differential thermal analysis.

Examples of the resin binder used together with the above-mentioned special metal citrate include polyvinyl acetate, ethylene-vinyl acetate copolymer (EVA), vinyl acetate-vinyl versatate copolymer (VA-VeoVa) and the like. Ester resins, saponified vinyl ester resins such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer, olefin polymers such as polyethylene and polypropylene, polyethylene terephthalate, polybutylene terephthalate, poly (1,4-dimethylol-)
Polyesters such as cyclohexane terephthalate), polyamides such as polyamide 46, polyamide 6, polyamide 66, polyamide 610, polyamide 612, polyamide 11, and polyamide 12, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene- Methacrylic acid copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, vinylidene chloride-vinyl acetate copolymer, halogen-containing polymers such as polychloroprene,
Acrylic resin, acrylic polymer such as styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene polymer such as polystyrene, styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, methylcellulose And cellulose polymers such as hydroxyethyl cellulose and cellulose acetate, and natural polymers. Further, examples thereof include thermosetting acrylic resins, unsaturated polyester resins, vinyl ester resins, diallyl phthalate resins, epoxy resins, urea resins, and phenol resins. Also,
Compounds prepared by reacting 2-hydroxyethyl acrylate (HEA) with acrylates such as trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetramethacrylate, tolylene diisocyanate, isophorone diisocyanate, etc., and reacting HEA with hexanediol and isophorone diisocyanate UV curable resins such as diacrylate of bisphenol A-diglycidyl ether. In addition, a resin having a phosphonic acid group and a water-soluble urethane resin such as a polyurethane emulsion and a polyurethane dispersion can be used. These may be used alone or in combination of two or more. These resin binders are usually used by dissolving them in an appropriate organic solvent or using water as a dispersion medium. Among them, a vinyl acetate resin emulsion is preferred. Optimally, it is a vinyl acetate resin emulsion in which the weight-based mixing ratio of vinyl acetate and water is set to 50/50. Such a vinyl acetate resin emulsion has an advantage that the viscosity of the emulsion is appropriate and the preparation of the retarder is easy because it is acidic.

The mixing ratio of the above-mentioned special metal citrate and the resin binder is appropriately set depending on the amount of the concrete material which delays the hardening and the amount of the concrete material which is removed by washing out.
15 to 50 parts by weight (hereinafter abbreviated as “parts”)
It is preferably set in the range of parts. More preferably, it is 20 to 40 parts.

The retarder of the present invention contains the above-mentioned special metal salt of citrate and a resin binder. When used, the retarder may be dissolved in an appropriate solvent or mixed and dispersed in a liquid resin binder to form a liquid viscous material. Is preferable from the viewpoint of workability. In this case, the liquid viscous material may contain other fillers within a range that does not impair the object of the present invention. Specifically, coloring agents, adhesives, adhesives, resin solutions, viscosity adjusting solutions, foaming agents, water-absorbing swelling agents, antioxidants, ultraviolet absorbers, heat stabilizers, plasticizers, antistatic agents,
Extenders, pigments and the like.

By using the retarder of the present invention, a wash-out pattern can be formed on the concrete surface as follows, for example, to express makeup. That is, first, as shown in FIG. 1, a base sheet 1 is prepared, and the above-mentioned retarder is applied on the surface of the base sheet 1 by screen printing, and dried and solidified to form a pattern by the retarder layer 2. I do. on the other hand,
An adhesive is applied to the entire back surface of the base sheet 1 to form an adhesive layer 3. Then, a release sheet 4 is stuck on the pressure-sensitive adhesive layer 3 to cover the pressure-sensitive adhesive layer 3, thereby producing a washing sheet 5. Then
As shown in FIG. 2, the pressure-sensitive adhesive layer 3 exposed by peeling and removing the release sheet 4 of the washing sheet 5
Is adhered to the surface of the mold 6 and fixed. Next, as shown in FIG. 3, the mold 6 to which the washing sheet 5 is fixed is arranged at a predetermined interval with respect to the other molds 6a, and these side openings (not shown) and the bottom are formed. The opening is closed with a plate 7 or the like, and a concrete material 8 is poured from the upper opening. In the figure, 9 is an aggregate in the concrete material. After curing the concrete material 8 into concrete by curing and curing, as shown in FIG. 4, the formwork 6 and the washing sheet 5 are separated from the concrete product 10. In this state, the portion of the surface of the obtained concrete product 10 which is in contact with the retarder layer 2 is suppressed or delayed in curing, so that a soft uncured surface layer 11 is formed. Next, water is sprayed on the concrete product 10 (for example, 2 to 2).
40 kg / cm ² ) to wash out the concrete of the uncured surface layer 11 as shown in FIG. Forming a concrete product 1
A washout pattern is formed on the surface of No. 0.

As the base sheet 1, sheets made of various materials such as paper, wood, plastic, rubber, and metal are used, but are not particularly limited. The thickness of the base sheet 1 is not particularly limited as long as the workability is not impaired, but is preferably set to 0.05 to 1 mm.

The application of the retarder to the base sheet 1 is not limited to screen printing, but may be performed by various methods such as brushing, spraying, roller coating, dipping and the like. Further, it may be applied so as to have a pattern shape, or may be applied to the entire surface of the base material sheet 1 and subjected to masking.

The thickness of the retarder layer 2 is 0.05 to 1 m
m is preferable. If the thickness is less than 0.05 mm, the effect of suppressing sufficient hardening of concrete cannot be obtained. If the thickness exceeds 1 mm, the amount of concrete material washed out becomes too large, the yield becomes poor, and it is necessary to repeat application and drying many times. This causes productivity to deteriorate.

The retarder of the present invention has a better effect than the conventional retarder when the washing method is carried out outdoors. However, the present invention is not limited to this case. A good wash pattern can be formed.

Next, examples will be described together with comparative examples.

First, prior to the examples, magnesium-calcium citrate (hereinafter referred to as “Mg-Ca citrate”) was produced according to the above-mentioned method to obtain a white powder.

It was confirmed as follows that the white powder was Mg · Ca citrate. That is, first, the white powder, citric acid, magnesium citrate (hereinafter, referred to as “Mg citrate”), and calcium citrate (hereinafter, referred to as “Ca citrate”) were prepared. Then, the white powder was analyzed by elemental analysis. The results are shown in FIG. The four compounds were analyzed by infrared spectroscopy (IR).
The results are shown in FIGS. The above four compounds were analyzed by differential thermal analysis. The results are shown in FIGS.

[Analysis Results by Elemental Analysis] As is apparent from FIG. 6, calcium (Ca) was added to the white powder.
And magnesium (Mg).

[Results of analysis by infrared spectroscopy (IR)]
As is clear from Fig. 8, in citric acid alone, the metal element
Prominently 1000cm^-1Absorption peak before and after is small
ing. Further, as is apparent from FIG.
In g, 940cm^-1The first half and 10 of the nearby double peak
70cm^-1The first half of the nearby double peak is prominent
You. Further, as is clear from FIG.
Then, 940cm^-1There is no peak near, but 10
70cm ^-1The second half of the nearby double peak is prominent
You. And, as is clear from FIG.
Is 940cm^-1Near the first half of the double peak
With 1070cm^-1The second half of the nearby double peak
Is out. Therefore, citric acid M
g and Ca citrate are characteristic.
-It can be said that Ca is synthesized.

[Analysis Results by Differential Thermal Analysis] FIGS.
As is clear from FIG. 14, the peak temperature of the white powder (see FIG. 11) is clearly different from the peak temperature of citric acid (see FIG. 12) and the peak temperature of Mg citrate (see FIG. 13). The peak temperature of Ca citrate (FIG. 14)
), But shifted to a higher temperature side. Therefore, in the white powder, the metal element bonded to citric acid is mainly calcium, but it is understood that magnesium is partially incorporated.

From the results of the above analysis, it was found that the above-mentioned white powder was composed of at least Mg.Ca
It can be seen that Mg · Ca citrate represented by the formula (3) is included.

[0036]

Examples 1 to 9 and Comparative Examples 1 to 3
This was blended with the components shown in Tables 1 and 2 below in the proportions shown in the same table to prepare retarders.

[0037]

[Table 1]

[0038]

[Table 2]

Next, a sheet for washing was produced by the following method using each of the above-mentioned retarders, and the water resistance, washability and linearity of the sheet for washing were evaluated. The results are shown in Tables 3 and 4 below. In addition, each evaluation was performed by the method shown below.

[Method of Manufacturing Washing Sheet] Table 1 above
And a retarder and a urethane prepolymer shown in Table 2 were prepared, and both were mixed at a ratio shown in the same table.
Each is applied by screen printing to a pattern formation scheduled portion on the surface of a base sheet made of paper on which both surfaces are coated (laminated with a polyethylene film) (application amount: 20 to 60 g / m ² ), and is heated at 20 ° C. for 4 hours. After drying and solidification, a retarder layer was formed. Subsequently, an adhesive made of an acrylic emulsion was applied to the back surface of each base sheet (application amount: 50 to 600 g / m ² ) to form an adhesive layer. Further, release paper coated with silicone wax was adhered to the above-mentioned pressure-sensitive adhesive layer to obtain each washing sheet.

[Water Resistance] First, each of the above-mentioned washing sheets was peeled off the release paper on the back side to expose the pressure-sensitive adhesive layer, and was adhered and fixed to the wall surface. Then, water was sprayed on the surface of the retarder layer of the fixed washing sheet. And
Evaluation was made by visually observing the surface of the retarder layer after spraying.
As a result, も の indicates that the retarder layer was not disturbed, and X indicates that the retarder layer was disturbed.

[Washability] Each of the above washout sheets is peeled off from the release paper on the back side to expose an adhesive layer, adhered and fixed to a formwork, framed, and poured concrete material. Room temperature curing without water resistance test (Dry)
Alternatively, after the water resistance test, the film was cured by normal temperature curing (Wet). Then, after the mold and the washing sheet were peeled off, washing was performed by spraying water (20 kg / cm ² ) to remove cement in the uncured surface layer of the surface, thereby obtaining a concrete product. Then, the surface of the thus obtained concrete product was visually observed. As a result, ◎ indicates that the pattern shape formed by washing was reproduced with extremely high accuracy, ○ indicates that the pattern shape was reproduced with high accuracy, and △ indicates that the pattern shape was reproduced to an extent that there was no problem in quality. Those having poor reproducibility and having a problem in quality were indicated by x.

[Linearity] In the above washability test,
The relationship between the setting amount and the setting time of the concrete material in the part in contact with the retarder layer was examined, and those that were in a proportional relationship were indicated as ○, those that were in a substantially proportional relationship as Δ, and those that were not in a proportional relationship as X. .

[0044]

[Table 3]

[0045]

[Table 4]

From the above results, it can be seen that in all of the examples, Mg.Ca citrate was not eluted by water and was retained in the retarder layer. In addition, when washing is performed after the contact with the concrete material, it can be seen that a good pattern shape is formed. Further, it is understood that the linearity is also good. In contrast, all comparative products
Mg · Ca citrate is eluted by water, and the retarder layer is disturbed. In addition, about washability,
In the case of Dry, a good pattern shape is formed, but in the case of Wet, a very good pattern shape is not formed. Furthermore, it is understood that the linearity is not good except for the product of Comparative Example 1.

[0047]

As described above, the retarder of the present invention contains the metal citrate represented by the general formula (1) and a resin binder. For this reason, the above-mentioned special metal citrate salt is not eluted by water from a coating film formed using the metal salt. Further, the special metal citrate has an excellent cement setting retarding ability. Therefore, when the washing method is performed using the above-described retarder, there is an advantage that a concrete product having a good washed pattern can be obtained.

In particular, when Mg.Ca citrate represented by the above formula (2) is used as the metal citrate, it seems to be particularly good as a cement setting retarder.

When the above-mentioned metal citrate is blended in the above-mentioned specific ratio, cement hardening retarding ability can be exhibited more effectively.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a sheet using a retarder of the present invention.

FIG. 2 is an explanatory diagram showing a state in which the sheet is attached to a mold.

FIG. 3 is an explanatory view showing a state where a concrete material is cast using the sheet.

FIG. 4 is an explanatory view showing a state in which a mold and a sheet are separated from a concrete product.

FIG. 5 is an explanatory view showing a state where an uncured surface layer of a concrete product is removed by washing out.

FIG. 6 is a graph showing the result of analyzing a white powder by elemental analysis.

FIG. 7 is a graph showing the result of analyzing a white powder by infrared spectroscopy (IR).

FIG. 8 is a graph showing the results of analyzing citric acid by infrared spectroscopy (IR).

FIG. 9 is a graph showing the results of analyzing Mg citrate by infrared spectroscopy (IR).

FIG. 10 is a graph showing the results of analyzing citrate Ca by infrared spectroscopy (IR).

FIG. 11 is a graph showing the result of analyzing a white powder by differential thermal analysis.

FIG. 12 is a graph showing the results of analyzing citric acid by differential thermal analysis.

FIG. 13 is a graph showing the results of analyzing Mg citrate by differential thermal analysis.

FIG. 14 is a graph showing the results of analyzing Ca citrate by differential thermal analysis.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshikazu Matsumoto 3600, Gezu, Kita-gaiyama, Komaki-shi, Aichi Prefecture Inside Tokai Rubber Industries Co., Ltd. Address Tokai Rubber Industries Co., Ltd. (72) Inventor Yasuyuki Mitsuru 2-21 Toricho, Nishi-ku, Nagoya City, Aichi Prefecture Sink Chemical Industry Co., Ltd.

Claims (4)

[Claims] 1. A cement setting retarder comprising a metal citrate represented by the following general formula (1) and a resin binder. Embedded image 2. The metal citrate according to the following formula (2):
The cement setting retarder according to claim 1, which is magnesium calcium citrate represented by the formula: Embedded image 3. The above metal citrate salt is represented by the following formula (3):
The cement set retarder according to claim 1, which is magnesium calcium citrate represented by the formula: Embedded image 4. The cement hardening according to claim 1, wherein the amount of the metal citrate is set to 15 to 50 parts by weight based on 100 parts by weight of the resin binder. Retarder.