JPS59128242A - Shrinkage decreasing agent effective for cement - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a good shrinkage reducing agent for cement.

Traditionally, cement mortar and concrete (hereinafter referred to as
It is called a cement composition. ) is prone to dry cracking. This is due to the large drying shrinkage of cement. Therefore, it is desired to reduce drying shrinkage of cement compositions.

In order to reduce the drying shrinkage of cement compositions, a method of mixing latex such as acrylic latex or synthetic rubber latex into the cement composition is used, but in this case, a large amount of relatively expensive latex is used. (for example,
Since it is necessary to mix it in an amount of about 20 to 30% by weight based on the cement, it is not only economically undesirable, but also causes a fatal defect that the strength of the cement composition is significantly reduced. Furthermore, the incorporation of a large amount of latex causes a serious drawback in that the nonflammability of the cement composition is impaired.

Furthermore, although inorganic expandable admixtures (for example, calcium sulfoaluminate-based expandable admixtures) have been developed in recent years, they are not sufficient to essentially reduce drying shrinkage.

Under such circumstances, the inventors conducted intensive studies on cement shrinkage reducing agents that do not have the above-mentioned drawbacks, and as a result, they arrived at the present invention.

That is, the present invention is based on the general formula (1) % formula % (1) (wherein R is an alkyl group having 1 to 7 carbon atoms or 4 carbon atoms
~7 cycloalkyl group, A is an alkylene group having 2 to 3 carbon atoms, X is a residue obtained by removing two carboxyl groups from a polycarboxylic acid, a is a number of 1 or 2, b is a number of 1 or 2, n is a number from 1 to 10, M is hydrogen, an alkali metal,
A good shrinkage reducing agent for cement comprising a compound represented by an alkaline earth metal or ammonium ion), and a compound represented by the general formula (1) and a fluorine-based surfactant or/and a silicone-based surfactant. It is a good shrinkage reducing agent for cement with improved shrinkage reducing effect.

The compound represented by the general formula (1) of the present invention is usually an aliphatic lower alcohol having 7 or less carbon atoms or a lower alcohol having a cycloalkyl group having 4 to 7 carbon atoms, and an alkylene oxide such as ethylene oxide or/and propylene oxide. It can be easily obtained by adding , followed by esterification using a polycarboxylic acid compound.

In the general formula (1), R is a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, an isobutyl group, a tertiary-butyl group, a pentyl group,
These include an alkyl group such as a hexyl group, and a cycloalkyl group such as a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a methylcyclohexyl group. Among these alkyl groups and cycloalkyl groups, alkyl groups having 1 to 7 carbon atoms are preferred, and alkyl groups having 3 or 4 carbon atoms are more preferred from the viewpoint of shrinkage reducing effect. If R is an alkyl group or a cycloalkyl group having 8 or more carbon atoms, not only will the shrinkage reducing effect be reduced, but the foaminess will increase and a large amount of air will be entrained in the cement composition, resulting in a decrease in strength. Therefore, it cannot be used.

In general formula (1), (OA) represents alkylene oxide. Here, A is an alkylene group having 2 to 3 carbon atoms, such as an ethylene group and/or a propylene group. Further, the number n of added moles of alkylene oxide represented by (OA)n is preferably 1 to 10. When n is less than 1, it cannot be used because the effect of reducing shrinkage is small. n is 1
If it is greater than 0, the shrinkage reducing effect becomes small and air is entrained in the cement composition, which is not preferable. Furthermore, from the viewpoint of the shrinkage-reducing effect, it is preferable to co-add ethylene oxide and propylene oxide as the alkylene oxide in a block or random manner. In this case, when the molar ratio of (ethylene oxide having an alkylene group having 2 carbon atoms)/propylene oxide having an alkylene group having 3 carbon atoms is within the range of 0 to 5, the compound of general formula (1) has a good It exhibits a shrinkage-reducing effect, and particularly when propylene oxide is added alone, it exhibits the best effect and is more preferred. In this case, alkylene oxides such as butylene oxide and styrene oxide are co-added with alkylene oxides having 2 to 3 carbon atoms to an extent that does not impede the performance of the cement composition (usually 50% by weight or less based on the total oxyalkylene). Also included within the scope of the present invention.

Examples of polycarboxylic acids constituting X in general formula (1) include aliphatic saturated acids such as oxalic acid, malonic acid, succinic acid, glucuric acid, adipic acid, pimelic acid, superric acid, azelaic acid, and sebacic acid. Dicarboxylic acids, aliphatic unsaturated dicarboxylic acids such as maleic acid and fumaric acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, and tricarboxylic acids such as tricarboxylic acid and benzene I-ricarboxylic acid. Things can be used. Among these polycarboxylic acids, saturated and unsaturated dicarboxylic acids having 1 to 4 carbon atoms other than the carboxyl group are preferred from the viewpoint of shrinkage reducing effect. Examples of these dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, and fumaric acid, with succinic acid, maleic acid, and fumaric acid being particularly preferred.

When the compound of general formula (1) of the present invention is used, the carboxylic acid group is usually used as a salt of an alkali metal such as lithium, sodium, or potassium, an alkaline earth metal such as calcium or magnesium, ammonia, or an organic amine. However, it can be used both in acid form and in partially neutralized form. Generally, it is preferable to use the sodium salt.

The shrinkage reducing agent of the present invention can obtain an excellent shrinkage reducing effect by using one or a mixture of two or more compounds represented by the general formula (1) as an essential component. When / and a silicone surfactant are used in combination, the shrinkage reducing effect is further improved due to a synergistic effect, which is very preferable. There are cationic, nonionic, and anionic types of fluorosurfactants and silicone surfactants that are used in combination with these, and any of these can be used, but cationic and nonionic types are more effective for cement shrinkage. It is preferable in terms of the reduction effect, and nonionic type is more preferable.

As the fluorosurfactant used in the present invention, commonly available commercially available ones can be used. A typical example of a cationic fluorosurfactant is a compound having a perfluoroalkyl group having 5 to 18 carbon atoms as a hydrophobic group, and a cationic hydrophilic group (for example, a quaternary ammonium base, etc.). There is. Examples include Florado FC-134 manufactured by Jujutsu 3M ■, Megafac F-150 manufactured by Dainippon Ink Chemical ■, Surflon S-121 manufactured by Asahi Glass, and Stargent 30 manufactured by Neos ■.
0.

Examples include F-TOP EF-123B and F-TOP EF-132 manufactured by Tohoku Seishi Co., Ltd. A typical example of a nonionic fluorosurfactant is a compound consisting of a perfluoroalkyl group having 5 to 18 carbon atoms as a hydrophobic group and a nonionic hydrophilic group (for example, an ethylene oxide adduct). be. For example, Florado FC-170C manufactured by Jujutsu 3M ■ Megafa i-ri F-1420, F-1440, F- manufactured by Dainippon Ink & Chemical ■
171, F-177, Surflon S-1 manufactured by Asahi Glass Co., Ltd.
41, Sturgient 200.251 manufactured by Neos ■,
F-TOP EF-121, EF-12 manufactured by Tohoku Fertilizer
2AXEF-122B, EF-122CXEF-
122A3 and the like. A typical example of anionic surfactant is a perfluoroalkyl group having 5 to 8 carbon atoms as a hydrophobic group, and an anionic hydrophilic group (for example, a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, etc.). There are compounds consisting of acid ester groups, etc.). This includes the 7o Lard FC-95 and PC-9 manufactured by Jumin 3M.
8, FC-126, FC-128, Dainippon Ink Chemical ■
Mega Fasoku F-110, F-113, F-1 manufactured by
20, F-812, F-191.

Surf 1ml manufactured by Asahi Glass Company: /S-111, S-1
12, S-113, Stargent 1O manufactured by Neos ■
O1150, EF-10 made by Tohoku Fertilizer Company
2, EF-103, EF-112, EF-123A'
, EF-123B, etc. In addition to the above, cationic, anionic, and nonionic fluorosurfactants are available from Daikin Industries, Kanto Denka, and Du Po.
nt, ICI, Hoechst, CIBA-G
It is also commercially available from EIGY companies, and these can also be used as the fluorosurfactant of the present invention.

In addition, the silicone surfactant used in the present invention includes a polysiloxane as a hydrophobic group, a cationic hydrophilic group (for example, a quaternary ammonium base), a nonionic hydrophilic group (for example, an alkylene oxide adduct), and a cationic hydrophilic group (for example, a quaternary ammonium base) etc.) and anionic hydrophilic groups (for example, sulfuric acid ester salts, phosphoric acid ester salts, carboxylic acid salts, etc.). In Japan, Toray Silicone ■, Shin-Etsu Silicone ■
, Toshiba Silicone, etc. are commercially available, and these various products can be used in the present invention.

The amount of the shrinkage reducing agent of the present invention to be used varies depending on the number of carbon atoms in the alkyl group and the number of carbon atoms in the alkylene group of the compound represented by the general formula (1), but is usually 0. '5～1
It is 0% by weight. If the amount used is less than 0.5% by weight, the effect of reducing shrinkage will be low, while if it exceeds 10% by weight, the strength of the cement composition will be about 2/3 or less compared to that without additives, making it impractical. Not enough. Also, general formula (1)
When the compound represented by the above is used in combination with a fluorosurfactant and/or a silicone surfactant, the shrinkage reducing effect increases due to a synergistic effect. When these surfactants are used together, the amount of each compound added is determined by the general formula (1
) is 0.3 to 10% by weight based on the cement, and fluorosurfactant is 50% by weight based on the cement weight.
~500 ppm, silicone surfactant is 0.05-1% by weight based on cement.

The means for adding a good shrinkage reducing agent to the cement of the present invention is the same as in the case of cement admixtures that are generally used, such as mixing an appropriate amount of the shrinkage reducing agent in advance with mixing water, or It is possible to adopt a method such as adding an appropriate amount of the shrinkage reducing agent during kneading of a mixture consisting of cement, aggregate, and water.

A good shrinkage reducing agent for the cement of the present invention can be used in combination with other (optional) ingredients. Such optional ingredients include metal chlorides such as calcium chloride and sodium chloride, metal sulfates such as sodium sulfate, known cement hardening accelerators such as organic amines such as triethanolamine, alcohols, sugars, starch, and glycerin. , known cement hardening retardants such as sodium polyphosphate, known reinforcing steel rust preventive agents such as sodium nitrite and calcium nitrite, lignin sulfonic acid, oxycarboxylic acid, naphthalene sulfonic acid formalin condensate, melamine sulfonic acid formalin condensate. Examples of the cement dispersant include known cement dispersants such as carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl starch, phosphorylated starch, and known cement thickening agents such as sodium alginate.

The method for constructing mortar or concrete to which the shrinkage reducing agent of the present invention has been added may be the same as conventional methods, such as troweling, filling into formwork, spraying, or pouring with a caulking gun. Further, the curing method may be any of air dry curing, humid air curing, water curing, heating accelerated curing (steam curing, autoclave curing, etc.), or these methods may be used in combination.

When the good shrinkage reducing agent for cement of the present invention is added to cement, the drying shrinkage can be significantly reduced compared to when no additive is added. In addition, the nonflammability of the cement composition is less likely to be impaired, and furthermore, even when added in a high amount (for example, on the order of several percent), the strength of the cement composition will not be significantly reduced.

The present invention will be explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 I got the result.

In addition, EO in Table 2 represents ethylene oxide, and PO represents propylene oxide.

Table 2 Example 3 1 mol of various polycarboxylic acids was added to 4 mol of propylene oxide per 1 mol of isopropyl alcohol.
half-esterification using mole, which was then neutralized to the sodium salt and added to the cement in an amount of 3.5% by weight. Note that when tricarballylic acid is used as the polycarboxylic acid, it is not a half ester, but one of the three carboxylic acid groups.
It is an esterification product of two carboxylic acid groups.

The shrinkage rate, air amount, and strength were measured in the same manner as in Example 1, and the results shown in Table 3 were obtained.

Table 3 Example 4 Tests were conducted in the same manner as in Example 1 using the shrinkage reducing agent No. 4 of Example 1 and varying the amount added, and the results shown in Table 4 were obtained.

Table 4 Example 5 Using 2.0% by weight of the good shrinkage reducing agent for cement in Example 1, 2.0% by weight of various fluorosurfactants based on the cement, or using silicone surfactants at 200ppm based on the cement. The shrinkage rate, air content, and strength were measured in the same manner as in Example 1 using 0.1% by weight of the agent based on the cement, and the results shown in Table 5 were obtained. Table 5 also shows the results when a fluorine-based surfactant and a silicone-based surfactant were used alone as comparative examples.

Table 5 Example 6 Using 2.0% by weight of the good cement shrinkage reducer 1-4 in Example 1 based on ordinary Portland cement,
Tests were conducted in the same manner as in Example 1 using Stargent 200 as the fluorosurfactant and 5H3771 as the silicone surfactant and varying the amounts added, and the results shown in Table 6 were obtained.

Table - 6 Procedural Amendment LM March 18, 1958 Mr. Kazuo Wakasugi, Director-General of the Ministry of Demand, 1, Clarification of the incident [Gyuen Ml! 18003117 No. 2, Name of the invention: Good shrinkage reduction of cement 3, 1ili correction case and ■ series Patent applicant 4, Agent ◎601-13! ! ! 075-57
1-11226, Subject of amendment■ Detailed explanation of the invention in the specification column 7, Contents of amendment 1 Detailed explanation of the invention in the specification column (1) Page 7, line 2, "~ethylene oxide)/ ``~ having 3 carbon atoms'' is corrected to ``~ethylene oxide)/(~ having 3 carbon atoms'').

(2) Table 1 on page 16, column 7 of Comparative Example
” should be corrected by deleting “〃” and reading “Additive-free.”

Claims (1)

[Claims] 1. The following general formula (1) % formula %] (In the formula, R is an alkyl group having 1 to 7 carbon atoms or 4 carbon atoms
~7 cycloalkyl group, A is an alkylene group having 2 to 3 carbon atoms, X is a residue obtained by removing two carboxyl groups from a polycarboxylic acid, a is a number of 1 or 2, b is a number of 1 or 2, n is a number from 1 to 10, M is hydrogen, an alkali metal,
A good shrinkage reducer for cement, consisting of compounds of alkaline earth metals or ammonium ions. 2. A good shrinkage reducing agent for cement according to claim 1, wherein in the general formula (1), R is an alkyl group having 1 to 4 carbon atoms. 3. A good shrinkage reducing agent for cement according to claim 2, wherein in the general formula (1), R is an alkyl group having 3 or 4 carbon atoms. 4. In the general formula (1), A is an alkylene group having 2 or 3 carbon atoms, and the molar ratio of (alkylene group having 2 carbon atoms)/(alkylene group having 3 carbon atoms) is 0 to 5. Claims 1, 2, or 3 within the scope
A good shrinkage reducer for cement according to any of paragraphs. 5. In general formula (1), X has 1 to 4 carbon atoms,
and a dicarboxylic acid residue, a good shrinkage reducing agent for cement according to any one of claims 1 to 4. 6. A good shrinkage reducing agent for cement according to claim 5, wherein the dicarboxylic acid is succinic acid, maleic acid, or fumaric acid. 7. A good cement shrinkage reducing agent comprising a compound represented by the general formula (1) and a fluorosurfactant or/and a silicone surfactant. 8. A good shrinkage reducing agent for cement according to claim 7, wherein the fluorosurfactant and/or the silicone surfactant are cationic or nonionic surfactants. 94. 8. A good shrinkage reducing agent for cement according to claim 7, wherein the fluorosurfactant and/or the silicone surfactant are nonionic surfactants.