JPH0153219B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cement dispersion composition with low slump loss. More specifically, the present invention relates to a dispersion composition for cement that has excellent cement dispersibility, has little slump loss, and does not delay the hardening time of concrete. Salts of naphthalene sulfonic acid formalin condensates or melamine sulfonic acid formalin condensates have the best cement dispersion ability among existing cement dispersants, and are therefore said to be able to significantly reduce the amount of concrete mixing water. It has unique characteristics and is used in large quantities in secondary concrete products that require high strength. However, salts of naphthalene sulfonic acid formalin condensate and salts of melamine sulfonic acid formalin condensate give concrete with excellent fluidity immediately after being mixed with cement, aggregate, water, etc., but after mixing, over time, The disadvantage is that the fluidity rapidly decreases as the temperature increases. This phenomenon of decreased fluidity is called slump loss, but it has the disadvantage that it is difficult to use for ready-mixed concrete, which requires that no large slump loss occur within 1.5 hours after mixing. have To improve slump loss,
A method was devised to adjust the timing of adding the salt of naphthalene sulfonic acid formalin condensate, for example, adding it after the cement has been hydrated by contact with water.
5692), which has a nearly satisfactory effect, but has the disadvantage that the addition method is complicated. On the other hand, it is known that the initial hydration of cement is involved in the increase in slump loss of concrete using salts of naphthalene sulfonic acid formalin condensate and salts of melamine sulfonic acid formalin condensate. In order to reduce slump loss, cement retarders are used in combination. Various types of setting retarders are known, including organic ones such as ligninsulfonic acid, nitrhumic acid and gluconic acid, and inorganic ones such as sodium tripolyphosphate. However, if these retarders are used in combination, the curing time of concrete will be delayed. Demolding of concrete is usually carried out within 1 to 3 days after concrete pouring.
For this reason, early strength (strength after 1 to 3 days) is very important, but it is naturally difficult to increase this early strength when the above-mentioned setting retarder is used in combination. For this reason, it is possible to use a retarder in combination with a setting retarder in the summer when concrete hardens very quickly, but it is difficult to use in the spring and autumn when concrete hardens not so quickly as it requires more time for demolding. However, it has the disadvantage that it cannot be used at all, especially in the winter when concrete hardens slowly. Under these circumstances, the present inventors have conducted intensive studies on a cement dispersion composition that has excellent cement dispersion ability, does not delay the hardening of cement, and has little slump loss, and as a result, has arrived at the present invention. That is, the present invention is a cement dispersion composition characterized by comprising the following two components (A) and (B). (A) Salt of naphthalene sulfonic acid formalin condensate and/or salt of melamine sulfonic acid formalin condensate 95 to 90 parts by weight (B) Structural unit represented by the following general formula () and structure represented by general formula () molar ratio of units is 9/1
5 to 50 parts by weight of a water-soluble polymer compound with a molecular weight of 1,000 to 50,000 within the range of ~1/9 General formula () (In the formula, R ₁ and R ₂ are hydrogen or a methyl group, A ₁ is an alkylene group having 2 to 3 carbon atoms, and m is a number from 1 to 20.) General formula () (In the formula, R ₃ is hydrogen or a methyl group, L is hydrogen or a -COOX ₂ group, and R ₄ is hydrogen, a methyl group, -
CH ₂ COOX A group selected from ₃ groups, X ₁ , X ₂ ,
X ₃ represents hydrogen, −(A ₂ O)lR ₅ or salt, X ₁ ,
At least one of X ₂ and X ₃ is hydrogen or a salt, A ₂ is an alkylene group having 2 to 3 carbon atoms, and l is 0 to 3.
20, _R5 is hydrogen, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl group having 4 to 7 carbon atoms) In the present invention, the salt of a naphthalene sulfonic acid formalin condensate is a salt obtained by condensing naphthalene sulfonic acid with a high degree of formalin condensation. It is a product obtained by neutralizing the same substance with caustic soda, calcium hydroxide, etc., such as those listed in Japanese Patent Publication No. 11737-1973 and Japanese Patent Publication No. 48-9564. Naphthalene sulfonic acid has α-
There are naphthalene sulfonic acid and β-naphthalene sulfonic acid, and β-naphthalene sulfonic acid is preferred. In addition, in the present invention, in addition to the formalin condensate salt of naphthalene sulfonic acid, other aromatic compounds and/or these sulfonic acids may be used as the salt of the formalin condensate of naphthalene sulfonic acid, as long as the performance is not impaired. It also includes co-condensed products. Examples of these include JP-A-51-
17219, JP-A No. 50-29644, JP-A No. 50-58120, and various others. Examples of these include aromatic compounds such as naphthalene and anthracene; aromatic sulfonic acids such as benzenesulfonic acid, anthracene sulfonic acid; Alkyl-substituted aromatic sulfonic acids such as; alkoxy-substituted benzene sulfonic acids such as methoxybenzenesulfonic acid; hydroxy-substituted benzene sulfonic acids such as phenolsulfonic acid; alkyl- and alkoxy-substituted benzene sulfonic acids such as ligninsulfonic acid; cresol sulfone Acids such as alkyl and hydroxy substituted benzene sulfonic acids and the like. The proportion of these naphthalene sulfonic acids and other aromatic compounds and/or these aromatic sulfonic acids which are co-condensed to an extent that does not impair their performance is generally 30 parts by weight or less per 100 parts by weight of naphthalene sulfonic acids. In addition, as the salt of the naphthalene sulfonic acid formalin condensate used in the present invention, sodium salt is usually used, but in addition to this, alkali metal salts such as lithium salts and potassium salts, calcium salts,
It can also be used as divalent metal salts such as magnesium salts, zinc salts, and iron salts, and trivalent metal salts such as aluminum salts and iron salts, as well as ammonium salts, organic amine salts, and alkanolamine salts. Also, two or more of these various salts may be used in combination. Further, the salt of melamine sulfonic acid formalin condensate used as component (A) of the present invention is a salt obtained by condensing melamine sulfonic acid with formalin, and may be a commercially available salt. For example, Mernant manufactured by Showa Denko K.K. and NL- manufactured by Pozolis Bussan.
4000, NP-20, etc. The salt of this melamine sulfonic acid formalin condensate is generally melamine and formaldehyde or paraformaldehyde sulfite (sodium sulfite, ammonium sulfite, sodium bisulfite, ammonium bisulfite, etc.)
in water under alkaline conditions (e.g. PH9-12).
(e.g. pH 4 to 6), or those that were subjected to an addition reaction under alkaline conditions and further condensed under weakly acidic conditions (for example, pH 4 to 6), or those that were further subjected to an addition reaction under alkaline conditions. Examples include those that are highly condensed under strong acidity (for example, pH 2 to 4). Among these, those that are highly condensed under strong acidity are more preferable than cement dispersibility. Furthermore, among the salts of naphthalene sulfonic acid formalin condensate and the salts of melamine sulfonic acid formalin condensate used as component (A) of the present invention, the salt of naphthalene sulfonic acid formalin condensate is more preferable than the cement dispersion ability. . The water-soluble polymer compound which is component (B) of the present invention has −COO (A ₁ O
)-mH group and at least one carboxyl group in the side chain as shown by the general formula (), or a salt thereof. Such polymer compounds are usually made by copolymerizing a monomer having a -COO(A ₁ O) mH group in its side chain and a monomer having at least one carboxyl group in its side chain in a predetermined ratio. It can be obtained by In this case, examples of monomers with −COO(A ₁ O) mH that give the structural unit of general formula () include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid.
Monoesterified products with glycols represented by HO (A ₁ O) mH, and monoesters made by adding ethylene oxide or propylene oxide to unsaturated monocarboxylic acids under mild conditions (for example, 60 to 80°C). Examples include esterified products. Examples of monomers having at least one carboxyl group in the side chain that provide the structural unit of general formula () include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, maleic acid, and citracon fumarate. Examples include unsaturated dicarboxylic acids such as acid, mesaconic acid, and itaconic acid. In addition, these unsaturated dicarboxylic acids and the general formula R ₅ O-(A ₂ O) lH (R ₅ is hydrogen, an alkyl group having 1 to 20 carbon atoms, or a carbon number 4 to
7, _A2 is an alkylene group having 2 to 3 carbon atoms, and 1 is a number from 0 to 20). At this time, if R ₅ has an alkyl group having 21 or more carbon atoms, or if 1 exceeds 20, this is not preferable because air entrainment increases and the strength of the concrete decreases. Component (B) of the present invention can also be obtained by methods other than those described above. For example, a polymer obtained by copolymerizing the monomer having the -COO(A ₁ O) mH group with the unsaturated dicarboxylic acids described above is further added with a predetermined amount of ethylene oxide or propylene oxide, and then esterified. Good too. In addition, the above-mentioned acrylic acid, methacrylic acid,
It may also be obtained by copolymerizing a homopolymer of unsaturated monocarboxylic acids such as crotonic acid, or copolymerizing the unsaturated monocarboxylic acids with the aforementioned unsaturated dicarboxylic acids such as maleic acid, and then adding ethylene oxide or propylene oxide. . In order to make the polymer thus obtained water-soluble, some or all of its carboxyl groups are usually used in the form of a salt.
The ionic moieties that form these salts include alkali metal ions such as lithium, sodium, and potassium, alkaline earth metal ions such as calcium and magnesium, trivalent metal ions such as aluminum and iron, ammonium, ethanolamine, and dimethyl. Mention may be made of ions from organic amines such as amines, triethylamine, triethanolamine, etc. Among component (B) of the present invention, the case where m in the general formula () is a number from 1 to 5 is preferable from the slump loss improving effect and cement dispersion ability.
Also, among the structural units of the general formula (), from the viewpoint of improving slump loss and cement dispersion ability, it is preferable that R ₂ and R ₃ are hydrogen or methyl groups and L is hydrogen, acrylic acid,
This is due to methacrylic acid and crotonic acid. In the component (B) of the present invention, it is essential that the molar ratio of the structural unit represented by the general formula () to the structural unit represented by the general formula () is within the range of 9/1 to 1/9. When this ratio exceeds 9/1, the effect of improving slump loss is not only reduced, but also the curing of concrete is slightly delayed, which is undesirable.When the ratio is less than 1/9, there is almost no effect of improving slump loss, which is undesirable. More preferably, this ratio is within the range of 7/3 to 3/7.
It is preferable because it has the greatest effect on improving slump loss, has excellent cement dispersion ability, and does not delay cement hardening at all. In addition, in the present invention, the polymer compound that is component (B) contains the above-mentioned carboxyl group and -COO(A ₂ O) -mH group in a predetermined ratio, but other unsaturated Monomers obtained by copolymerization can also be used. Examples of these other unsaturated monomers include esters such as acrylic esters and methacrylic esters (usually the number of carbon atoms in the ester moiety is 20 or less), diesters such as maleic acid and fumaric acid (HO (A ₂ O ), vinyl esters such as vinyl _acetate and vinyl propionate, vinyl aromatics such as styrene, sulfonic acids such as styrene sulfonic acid and vinyl sulfonic acid, and olefins such as butene and octene. I can list things. Copolymerization of acrylic esters, methacrylic esters, styrene sulfonic acids, etc. in which the number of carbon atoms in the ester group is 5 or less may actually improve the cement dispersion ability and give favorable results in some cases. The amount of these other unsaturated monomers added varies depending on the type of hydroxyl group or carboxyl group in component (B), their equivalent ratio, etc., but is usually 30% by weight or less. The content of carboxyl groups (before neutralization) in component (B) is usually 2 to 60% by weight, and the content of oxyalkylene groups is usually 5 to 70% by weight. Such a water-soluble polymer compound can be obtained according to a method commonly used in industry. For example, radical polymerization is common as a form of reaction, and solution polymerization is preferred at this time.
Water, lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol, hydrocarbons such as benzene, and ketones such as acetone and methyl ethyl ketone are used as solvents. Polymerization initiators include peroxides such as benzoyl peroxide and tert-butyl peroxide, azo compounds such as azobisisobutyronitrile, and even persulfates, depending on the type of solvent and the type of monomer. They can be selected as appropriate, and since the activation energy for decomposition is small, polymerization can be initiated under mild conditions. The copolymer thus obtained can be used as a cement dispersant as an acid, but it can also be neutralized with an alkali substance and used as an alkali metal salt, alkaline earth metal salt, or ammonium or organic amine salt. . The molecular weight can be adjusted by changing the monomer concentration in the solvent, reaction temperature, and reaction time, but those with a molecular weight in the range of 1000 to 50000 have particularly good water solubility and good dispersibility in cement. It is.
If the molecular weight is less than 1000, the slump loss becomes large, causing a delay in setting. Moreover, when it exceeds 50,000, the water reduction performance of the salt of the naphthalene sulfonic acid formalin condensate decreases and the slump loss increases. More preferable molecular weight is 3000-30000
It is within the range of The pure ratio of components (A) and (B) of the present invention is 95% of component (A).
~50 parts by weight, 5 to 50 parts by weight of component (B).If component (B) is less than 5 parts by weight, the effect of improving slump loss will be small, and if it exceeds 50 parts by weight, it will slightly affect the hardening of cement. It will be delayed and the slump loss will also increase. Preferably component (A) 90 to 60 parts by weight, component (B) 10 to 40 parts by weight, more preferably (A) 90 to 70; (B) 10
~30 parts by weight. In addition to the above-mentioned components (A) and (B), other components (optional components) can be added to the cement dispersion composition of the present invention as needed. Such optional ingredients include known air entraining agents such as alkylbensene sulfonates, sulfuric ester salts of higher fatty acid alkylene oxide adducts, and Vinzol; ligninsulfonic acid and polyalkylene glycol-based cement dispersants; calcium chloride. , known cement hardening accelerators such as sodium chloride, sodium sulfate, soda carbonate, potassium carbonate, sodium thiosulfate, and alkanolamines; ligninsulfonic acid, gluconic acid,
Known cement retardants such as citric acid, tartaric acid, polyphosphoric acid; polyvinyl alcohol, starch,
Various substances can be added, such as known glue agents such as methyl cellulose and hydroxymethyl cellulose; known rust preventive agents such as sodium nitrite and calcium nitrite. Examples of cements that can be used in the dispersion composition of the present invention include ordinary Portland cement, early strength Portland cement, moderate heat Portland cement, alumina cement, fly ash cement, and blast furnace cement. Among these, the preferred one is ordinary portland cement. The amount of the dispersion composition of the present invention added can be varied depending on the use of the cement and the required performance, but the amount of the dispersion composition of the present invention added is usually 0.01 to 5% by weight, preferably 0.01 to 5% by weight, based on the cement. is 0.1~1
Weight%. It is usually 0.1 to 0.5% by weight for ready mix concrete, and 0.4 to 1% by weight for secondary concrete products. This dispersion composition is usually added when cement and aggregate (sand, crushed stone, etc.) are mixed and mixed with mixing water. It may be added after 2 minutes or more, or it may be added to cement in advance and then water is added. Furthermore, a divided addition method may be used in which a part of the present dispersion composition is added during kneading, and then the remaining present dispersion composition is added in one or more divided portions. Furthermore, each component constituting the composition of the present invention may be added separately to cement, aggregate, water, etc. and kneaded, or each component may be added separately at various stages of the cement mortar or concrete mixing process. The effects of the present invention can be obtained if the composition of the present invention is produced in the final cement product.
It can also be used in this way. The method for constructing mortar and concrete containing the dispersion composition of the present invention may be the same as conventional methods, and various methods may be used, such as troweling, spraying, filling into formwork, and injection using a caulking gun. or,
Curing methods include air dry curing, moist air curing, water curing,
Any heating accelerated curing (steam curing, autoclave curing, etc.) may be used, or a combination of each may be used. The dispersion composition of the present invention has an extremely excellent cement dispersion ability, and has the features of not slowing down cement hardening and having little slump loss. Taking advantage of this feature, this dispersion composition is used for mortar and concrete for roofs, walls, and floors; waterproof mortar, waterproof concrete, building frames, and molded parts of buildings, etc., and has particularly low slump loss. Due to its characteristics, it is suitable for ready-mix concrete used in the framework of buildings, etc. Also, due to its excellent dispersibility, it can be used as mortar and concrete dispersion compositions for producing secondary concrete products. Are suitable. The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Note that all parts in the examples indicate parts by weight based on pure content. Example 1 As component (A), sodium salt of naphthalene sulfonic acid formalin condensate (hereinafter abbreviated as NSF) 75
Part (B) is a water-soluble product with a molecular weight of 5,000 to 10,000 obtained by copolymerizing 50 mol% of hydroxyethyl methacrylate (hereinafter abbreviated as HEMA) and 50 mol% of monomers having various carboxyl groups shown in Table 1. A composition of the present invention was obtained using 25 parts of a sodium salt of a polymer compound. Using these, the following concrete mixture was prepared and the slump loss, setting time and strength of the concrete were measured, and the results shown in Table 1 were obtained. or,
In Table 1, for comparison with the composition of the present invention,
When using NSF alone, when using NSF and sodium gluconate as oxycarboxylic acid,
When NSF is used in combination with sodium polyacrylate, which has only carboxyl groups in the molecule, and soda salt of a copolymer of 50 mol% maleic anhydride and 50 mol% isobutene, lignin-based commercially available water reducing agents (Pozolith NO5L, standard We also show the results for the case (type). Table 1 also shows the results obtained when no dispersion composition was used. As for the mix of concrete, the dispersion composition was 0.2% (based on cement, pure content), unit cement amount was 320 kg/m ³ , water/cement ratio was 55%, and fine aggregate percentage was 46%. The concrete mix when no dispersion composition is used is a unit cement amount of 320
Kg/m ³ , water/cement ratio of 60%, and fine aggregate ratio of 46%. In addition, the concrete temperature is 20℃, and the compressive strength is
This is the value when cured in water at 20℃. In Table 1, maleic acid EO _1.0 , EO _3.0 ,
EO _5.0 PO _3.0 is a monoester of maleic acid in which 1 mol of each of ethylene glycol, triethylene glycol, pentaethylene glycol, and tripropylene glycol is added to 1 mol of maleic anhydride.

【table】

[Table] (*) Slump loss amount is the difference between the slump immediately after kneading and the slump after 30 minutes, 60 minutes, and 90 minutes. The larger this value is, the more severe the decline in concrete fluidity is. As is clear from Table 1, the product of the present invention has significantly improved slump loss compared to the case of NSF alone.
In addition, slump loss is reduced compared to lignin-based water reducing agents commonly used in ready-mixed concrete. Furthermore, what is noteworthy about the product of the present invention is not only that the slump loss is reduced, but also that there is almost no delay in hardening of the concrete. Since the product of the present invention has no curing delay, it satisfies the standard water reducing agent standards set by the Architectural Institute of Japan (according to the same standards, compared to the case without a dispersant, both the initial and final water reducer are 1.
A standard type is defined as one that is not more than 1 hour and 30 minutes late. ) On the other hand, when using the conventional technology, sodium gluconate, the slump loss was reduced, but the curing of the concrete was significantly delayed and early strength (measured as strength after 1 day) was not achieved at all. ,Practical,Spring,Autumn,
It turns out that it cannot be used in the winter. Example 2 75 parts of sodium salt of melamine sulfonic acid formalin condensate (hereinafter abbreviated as MSF) as component (A),
(B) Hydroxyethyl methacrylate 50 as component
Molecular weight 5000 obtained by copolymerizing mol% and 50 mol% of monomers having various carboxyl groups shown in Table 2.
~10000 Sodium Salts of Water-Soluble Polymer Compounds 25
A composition of the present invention was obtained using 1.0 parts. Using these, various concrete tests were conducted in the same manner as in Example 1, and the results shown in Table 2 were obtained. Table 2 also shows the results when MSF was used alone for comparison.

【table】

[Table] Example 3 75 parts of NSF as component (A), 50 mol% of acrylic acid as component (B), and 50 mol% of various -COO-(A ₁ O) mH group-giving monomers were copolymerized. molecular weight obtained by
A composition of the present invention was obtained using 25 parts of a sodium salt of a water-soluble polymer compound having a concentration of 5,000 to 10,000. Using these, various concrete tests were conducted in the same manner as in Example 1, and the results shown in Table 3 were obtained. In addition, expressions such as acrylic acid EO _1.0 and EO _3.0 in Table 3 are the addition of _1.0 mol and _3.0 mol of ethylene oxide to 1 mol of acrylic acid, and PO indicates propylene oxide, and the same applies to other expressions. .

[Table] Example 4 Dispersion composition using 75 parts of NSF as component (A) and 25 parts of sodium salt of a copolymer with a molecular weight of approximately 8000 made by varying the copolymerization composition of acrylic acid and HEMA as component (B). Various concrete tests were conducted in the same manner as in Example 1, and the results shown in Table 4 were obtained.

[Table] Example 5 Using NSF as the (A) component, 50 mol% of acrylic acid and 50 mol% of HEMA as the (B) components with a molecular weight of 8000.
Cement dispersion compositions were obtained using the sodium salt of the copolymer of , and varying the blending ratios of component (A) and component (B). Using these, various concrete tests were conducted in the same manner as in Example 1, and the results shown in Table 5 were obtained.

[Table] Example 6 A cement dispersion composition was prepared using 75 parts of NSF as the component (A) and 25 parts of a sodium salt of a copolymer with a different molecular weight of 50 mol% of acrylic acid and 50 mol% of HEMA as the component (B). Using these, various concrete tests were conducted in the same manner as in Example 1, and the results shown in Table 6 were obtained.

【table】

Claims (1)

[Scope of Claims] 1. A dispersion composition for cement with low slump loss, characterized by comprising the following two components (A) and (B). (A) Salt of naphthalene sulfonic acid formalin condensate and/or salt of melamine sulfonic acid formalin condensate 95 to 50 parts by weight (B) Structural unit represented by the following general formula () and structure represented by general formula () molar ratio of units is 9/1
5 to 50 parts by weight of a water-soluble polymer compound with a molecular weight of 1,000 to 50,000 within the range of ~1/9 General formula () (In the formula, R ₁ and R ₂ are hydrogen or a methyl group, A ₁ is an alkylene group having 2 to 3 carbon atoms, and m is a number from 1 to 20.) General formula () (In the formula, R ₃ is hydrogen or a methyl group, L is hydrogen or a _-COOX2 group, R ₄ is hydrogen, a methyl group,
−CH ₂ COOX A group selected from ₃ groups, X ₁ ,
X ₂ and X ₃ each independently represent hydrogen, a −(A ₂ O)lR ₅ group, or a salt, at least one of X ₁ , X ₂ , and X ₃ is hydrogen or a salt, and A ₂ has 2 to 2 carbon atoms.
3, l is a number from 0 to 20, R ₅ is hydrogen, an alkyl group having 1 to 20 carbon atoms, or a cycloalkyl group having 4 to 7 carbon atoms). 2. The dispersion composition according to item 1, wherein component (A) is a salt of a naphthalene sulfonic acid formalin condensate. 3 The molar ratio of the structural unit represented by the general formula () to the structural unit represented by the general formula () is 7/3 to
The dispersion composition according to item 1 or 2, which is within the range of 3/7. 4. The dispersion composition according to any one of item 1, item 2, and item 3, wherein R ₃ and R ₄ in the general formula () are hydrogen or a methyl group, and L is hydrogen. 5 The first where m in the general formula () is a number from 1 to 5
The dispersion composition according to any one of Items 1, 2, 3, and 4. 6 (B) Components 1 to 1 whose molecular weight is 3000 to 30000
The dispersion composition according to any one of Item 5.