JPH0153223B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a shrinkage reducing agent for cement. Conventionally, one of the serious drawbacks of cement mortar and concrete (hereinafter referred to as cement compositions) is that they are susceptible 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 has been used, but in this case, a large amount of relatively expensive latex ( For example, 20~
(approximately 30% by weight), which is not only economically undesirable, but also causes a fatal defect in 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. 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. On the other hand, fatty acid esters of sorbitan or their ethylene oxide adducts are well known as setting retarders and air entraining agents for cement, and are in practical use. When used as a setting retarder, a mixture of 0 to 4 moles of ethylene oxide added to 1 mole of sorbitan fatty acid ester is usually used, and when used as an air entrainment agent, sorbitan fatty acid ester is usually used. A compound obtained by adding about 20 moles of ethylene oxide to 1 mole of ester is used. As a result of intensive research into compounds that have an excellent shrinkage-reducing effect on cement, the present inventors surprisingly found a compound to which ethylene oxide is added at a specific ratio of 5 to 15 moles per mole of sorbitan fatty acid ester. has a good shrinkage-reducing effect on cement, and a block-shaped co-adduct in which 5 to 15 moles of propylene oxide is added and then ethylene oxide is added in a specific proportion has a particularly excellent shrinkage-reducing effect. The present invention was achieved by discovering that cement has little retardation of setting and almost no air entrainment. That is, the present invention is based on the general formula (1) (In the formula, R is an alkyl group having 4 to 18 carbon atoms, EO
is an ethylene oxide residue, PO is a propylene oxide residue, (a+b+c) is a number from 5 to 15,
(d+e+f) is a number from 0 to 15, -(PO)-
(EO)- indicates that the ethylene oxide residues and propylene oxide residues are random or block-shaped. ), and a cement shrinkage-reducing agent containing a compound represented by general formula (1) and a fluorine-based surfactant or/and a silicone-based surfactant, which has an improved shrinkage-reducing effect. It is a shrinkage reducing agent for cement. The compound of general formula (1) of the present invention is usually produced by esterifying sorbitol with a fatty acid and then cyclodehydrating it, or adding a predetermined amount to a sorbitan fatty acid ester obtained by esterifying sorbitol with a fatty acid and then cyclodehydrating it. It can be obtained by adding alkylene oxide. At this time, the fatty acids used in the present invention have an alkyl group having 4 to 18 carbon atoms, and specifically include valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, and undecyl acid. Examples include saturated fatty acids such as acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, and nonadecanoic acid, and unsaturated fatty acids such as undecylenic acid, oleic acid, and elaidic acid. When a fatty acid having an alkyl group having 3 or less carbon atoms is used, the shrinkage reducing effect is significantly reduced. Also, carbon number 19
If a fatty acid having the above alkyl group is used, not only the effect of reducing shrinkage will be lowered, but also the effect of retarding the setting of cement will become noticeable, which is not preferable. Most preferred are fatty acids having an alkyl group of 11 to 17 carbon atoms. In the general formula (1) of the present invention, -(EO)- represents an ethylene oxide residue, and -(PO)- represents a propylene oxide residue. It is essential that (a+b+c), which indicates the number of moles of ethylene oxide added, is in the range of 5 to 15. If (a+b+c) is less than 5, the shrinkage reducing effect will not be significantly reduced, and it will have a significant setting retarding effect on the cement, which is not preferable. Also, if (a+b+c) exceeds 15,
Similarly, the shrinkage reduction effect is significantly reduced,
This is not preferable because air entrainment property also increases significantly. Most preferably, (a+b+c) is 7 to 12
This is the case for numbers within the range of . Furthermore, the compound of the present invention may be used to which ethylene oxide alone is added, but it is preferable to further co-add propylene oxide in a block or random manner, since this greatly improves the shrinkage-reducing effect. It is essential that (d+e+f), which indicates the number of moles of propylene oxide added, is a number within the range of 0 to 15. If this (d+e+f) exceeds 15, not only will the shrinkage reduction effect decrease, but also a defoaming effect will appear, and the concrete will have a predetermined amount (for example, 4
%) is difficult to entrain, which is not preferable. The most preferred is (d+e+f)
is a number between 5 and 10, and (a+b+c)/
This is the case when the ratio of (d+e+f) is within the range of 1 to 2. Regarding the addition form of ethylene oxide and propylene oxide, a block-like co-adduct is preferable to a random-like co-adduct from the viewpoint of shrinkage reduction effect. The coadduct has the greatest shrinkage-reducing effect and is more preferable. In addition to ethylene oxide and propylene oxide, the present invention also includes co-addition of oxides such as butylene oxide and styrene oxide within a range that does not impair the performance of the cement composition (usually 50% by weight or less of the total oxyalkylene). Included within the scope of. The cement 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. or/
When a silicone surfactant 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 type surfactants to be used together with these, and any of these can be used, but cationic and nonionic types cause cement shrinkage. It is preferable in terms of the reduction effect, and nonionic type is more preferable. As the fluorine-containing surfactant used in the present invention, commonly available commercially available surfactants can be used. Typical examples of cationic futusol surfactants include perfluoroalkyl groups having 5 to 18 carbon atoms as hydrophobic groups;
There are compounds having this and a cationic hydrophilic group (eg, quaternary ammonium base, etc.). For example, Florado FC- manufactured by Sumitomo 3M Ltd.
134, Megafac F manufactured by Dainippon Ink Chemical Co., Ltd.
-150, and others include Surflon S-121 manufactured by Asahi Glass Co., Ltd., Sturgient 300 manufactured by Neos Co., Ltd., Eftup EF-123B manufactured by Tohoku Fertilizer Co., Ltd.,
Examples include EF-132. Typical examples of nonionic fluorocarbon surfactants include those with a carbon number of 5 to 18.
There is a compound consisting of a perfluoroalkyl group as a hydrophobic group and a nonionic hydrophilic group (for example, an ethylene oxide adduct). for example,
Florado FC-170C manufactured by Sumitomo 3M Ltd.
Megafuck F- manufactured by Dainippon Ink Chemical Co., Ltd.
142D, F-144D, F-171, F-177, Asahi Glass Co., Ltd.
Surflon S-141 manufactured by Neos Co., Ltd., Sturgient 200, 251 manufactured by Neos Co., Ltd., Eftup EF-121, EF-122A, EF-122B, EF- manufactured by Tohoku Fertilizer Co., Ltd.
Examples include 122C and EF-122A3. Typical examples of anionic surfactants include a perfluoroalkyl group having 5 to 18 carbon atoms as a hydrophobic group, and an anionic hydrophilic group (e.g., sulfonic acid group, carboxylic acid group, phosphoric acid group). ester group, etc.)
There is a compound consisting of These include Florado FC-95, FC-98, and FC manufactured by Sumitomo 3M Limited.
-126, FC-128, Megafuck F-110, F-113, F-120, F- manufactured by Dainippon Ink Chemical Co., Ltd.
812, F-191, Surflon S- manufactured by Asahi Glass Co., Ltd.
111, S-112, S-113, Sturgient 100, 150 manufactured by Neos Co., Ltd., Eftup manufactured by Tohoku Fertilizer Co., Ltd.
EF-102, EF-103, EF-112, EF-123A, EF
-123B etc. In addition to the above,
Cationic, anionic, and nonionic surfactants are available from Daikin Industries, Ltd., Kanto Denka Co., Ltd., and Du
It is also commercially available from companies such as Pont, ICI, Hoechst, and CIBA-GEIGY, and these can also be used as the fluorine-based surfactant of the present invention. In addition, the silicone surfactant used in the present invention refers to a polysiloxane with a hydrophobic group, a cationic hydrophilic group (e.g., quaternary ammonium base), a nonionic hydrophilic group (e.g., an alkylene oxide adduct) ), anionic hydrophilic groups (e.g. sulfate ester salts, phosphate ester salts,
carboxylic acid salts, etc.). In Japan, Toray Silicone Co., Ltd., Shin-Etsu Silicone
Various products are commercially available from companies such as Toshiba Silicone Co., Ltd. and Toshiba Silicone Co., Ltd., and these various products can be used in the present invention. The amount of the cement shrinkage reducing agent of the present invention is determined by the number of carbon atoms in the alkyl group of the compound represented by general formula (1),
Although it varies depending on the number of carbon atoms in the alkylene group, it is usually 0.5 to 10% by weight based on the cement. If the amount used is less than 0.5% by weight, the shrinkage reduction effect will be small;
On the other hand, if it exceeds 10% by weight, the strength of the cement composition will be about 2/3 or less compared to that without additives.
Not enough in terms of practicality. Further, when the compound represented by the general formula (1) is used in combination with a fluorine-based surfactant and/or a silicone-based surfactant, the shrinkage reducing effect increases due to a synergistic effect. When these surfactants are used together, the amount of each compound added is 0.3 to 10% by weight of the compound represented by general formula (1) based on the cement weight, and 50% to 10% of the weight of the cement for the fluorine-based surfactant. 500 ppm, and the silicone surfactant is 0.05 to 1% by weight based on the cement. The means for adding the cement shrinkage reducing agent of the present invention is as follows:
This is the same as in the case of commonly used cement admixtures. For example, an appropriate amount of the shrinkage reducing agent may be mixed in advance with the mixing water, or an appropriate amount of shrinkage reducing agent may be added during mixing of a mixture of cement, aggregate, and water. Means such as adding a shrinkage reducing agent can be adopted. The shrinkage reducing agent used in the cement of the present invention is
It can be used in combination with other components (optional). Such optional components 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, lees, Known cement hardening retardants such as glycerin and sodium polyphosphate, known reinforcing steel rust preventive agents such as sodium nitrite and calcium nitrite, lignin sulfonic acid,
Known cement dispersants such as oxycarboxylic acid, naphthalene sulfonic acid formalin condensate, and melamine sulfonic acid formalin condensate; known cement pastes such as carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl starch, phosphorylated starch, and sodium alginate; Various agents can be mentioned. 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, and injection 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 cement shrinkage reducing agent of the present invention is added to cement, a significant reduction in drying shrinkage is achieved compared to the case where no cement 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 After esterifying sorbitol with various fatty acids shown in Table 1, 10 moles of ethylene oxide and 7 moles of propylene oxide were randomly added to the sorbitan fatty acid ester obtained by cyclodehydration to produce the cement product of the present invention. A shrinkage reducing agent was obtained. For cured mortar obtained by adding these shrinkage reducing agents as pure components at a ratio of 3.5% by weight to ordinary Portland cement, the shrinkage rate was measured using the dial method of JIS A1129, and the strength was measured using JIS R5201. The air content was measured using concrete according to JIS A1128. Condensation is water/cement ratio 30
% of cement paste using a JIS R5201 Vicat needle. These results are shown in Table-1. The mortar used to measure shrinkage and strength had a water/cement ratio of 65% and a sand/cement ratio of 200%. The concrete whose air content was measured had a unit cement amount of 300 g/m ³ , a water/cement ratio of 60%, and a fine aggregate percentage of 44%. As the ordinary Portland cement, Asano ordinary Portland cement manufactured by Nippon Cement Co., Ltd. was used. Table 1 lists only the fatty acids constituting R in general formula (1), which is the starting material for the cement shrinkage reducing agent. This indicates that a cement shrinkage reducing agent was added and tested.

[Table] Example 2 A cement shrinkage reducing agent was prepared by varying the number of moles of alkylene oxide added to sorbitan oleate monoester obtained from oleic acid and sorbitol. These shrinkage reducing agents were added in an amount of 3.5% by weight to ordinary Portland cement, and the shrinkage rate, air content, setting time, and strength were measured in the same manner as in Example 1, and the results shown in Table 2 were obtained. In this case, the ethylene oxide/propylene oxide ratio was set to 1, and the oxides were added randomly.

【table】

[Table] Example 3 Cement obtained by adding 7 moles of propylene oxide to sorbitan oleate monoester obtained from oleic acid and sorbital using a conventional method, and then adding 10 moles of ethylene oxide to form a block-like co-adduct. A anti-shrinkage reducing agent was obtained. Mortar was prepared by changing the amount of the shrinkage reducing agent added in the same manner as in Example 1, and the shrinkage rate, air amount, setting time, and strength were measured, and the results shown in Table 3 were obtained.

【table】

[Table] Example 4 The cement shrinkage reducing agent of Example 3 was used at 2.0% by weight based on ordinary Portland cement, and various futsuo-based surfactants were used at 200 ppm based on the cement.
Alternatively, a silicone surfactant was used in an amount of 0.1% by weight based on the cement, and the shrinkage rate, air content, and strength were measured in the same manner as in Example 1, and the results shown in Table 4 were obtained.

【table】

[Table] Example 5 The cement shrinkage reducing agent of Example 3 was used in an amount of 2.0% by weight based on ordinary Portland cement, Surflon S-141 was used as the futsuo-based surfactant, and SH3747 was used as the silicone-based surfactant. A test was conducted in the same manner as in Example 1 by changing the amount, and the results shown in Table 5 were obtained.

【table】

Claims (1)

[Claims] First-order general formula (1) (In the formula, R is an alkyl group having 4 to 18 carbon atoms, EO
is an ethylene oxide residue, PO is a propylene oxide residue, (a+b+c) is a number from 5 to 15,
(d+e+f) is a number from 0 to 15, -(PO)-
(EO)- indicates that the ethylene oxide residues and propylene oxide residues are random or block-shaped. ) A shrinkage reducing agent for cement consisting of a compound represented by 2. The cement shrinkage reducing agent according to claim 1, wherein in the general formula (1), R is an alkyl group having 11 to 17 carbon atoms. 3 In general formula (1), (a+b+c) is 7 to 12
The cement shrinkage reducing agent according to claim 1 or 2, which has a number of . 4 In general formula (1), (d+e+f) is 5 to 10
and (a+b+c)/(d+e+
The cement shrinkage reducing agent according to claim 1, 2 or 3, wherein the ratio of f) is within the range of 1 to 2. 5. Any one of claims 1 to 4, wherein -(PO)-(EO)- in general formula (1) is a block-like co-adduct of a propylene oxide residue and an ethylene oxide residue. Shrinkage reducing agent for cement as described. 6 In general formula (1), -(PO)-(EO)- is a block-like coadduct in which an ethylene oxide residue is added to a propylene oxide residue, and the terminal thereof is an ethylene oxide residue. The cement shrinkage reducing agent according to any one of claims 1 to 5. 7. A cement shrinkage reducing agent comprising a compound represented by the general formula (1) and a fluorine-based surfactant or/and a silicone-based surfactant. 8. The cement shrinkage reducing agent according to claim 7, wherein the fluorine-based surfactant and/or the silicone-based surfactant are cationic or nonionic surfactants. 9. The cement shrinkage reducing agent according to claim 7 or 8, wherein the futsuo-based surfactant and/or the silicone-based surfactant are nonionic surfactants.