JPH05246743A - Dispersant for cement - Google Patents

Abstract

PURPOSE:To improve antifoaming effect by compounding a specified amt. of nonion surfactant and silicone oil into salts of copolymers of vinyl monomers and alpha,beta-unsatd. dicarboxylic acid anhydride. CONSTITUTION:Copolymers having 500-100000 number average mol.wt. is prepared by polymn. of vinyl monomers having 4-10 carbon number such as isobutylene and alpha,beta-unsatd. dicarboxylic acid anhydride such as maleic acid anhydride with specified molar ratio in the presence of a radical polymn. initiator. Then the copolymers are hydrolyzed in the presence of 0.8-2mol base to 1mol of the acid anhydride of the copolymer. To 100 pts.wt. of produced alkali metal salt or ammonium salt of copolymers, 0.3-10 pts.wt. nonion surfactant having >=12 HLB such as polyoxyethylene-polyoxypropylene adduct and 0.001-1 pt.wt. of silicone oil having a polyorganosiloxane structure and 100-10000cSt viscosity are added to obtain a cement dispersant having an excellent antifoaming effect.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a uniform dispersant for cement having a low foaming property.

[0002]

Conventionally, as a cement dispersant, alkali metal salts of copolymers such as isobutylene-maleic acid, isoamylene-maleic acid, diisobutylene-maleic acid, styrene-maleic acid and vinyl acetate-maleic acid, Water-soluble salts of copolymers of vinyl monomers and unsaturated dicarboxylic acid anhydrides such as ammonium salts and polyvalent metal salts are known. Among these, when a water-soluble salt of a copolymer of a vinyl-based monomer having 4 to 10 carbon atoms and an unsaturated dicarboxylic acid anhydride is used in a cement slurry used for soil improvement, the viscosity of the cement slurry changes with time. Has a small effect and a long pot life.

However, since the water-soluble salt of the copolymer generally has a foaming property, when it is used as it is as a dispersant for cement, the cement slurry may foam. Such a case is generally solved by adding an antifoaming agent when the aqueous dispersant solution for cement is used. However, in this method, the work at the time of use becomes complicated, and since the amount of the defoaming agent used is generally small, it is difficult to quantitatively add it, and the amount of addition varies greatly. These problems can be solved if an aqueous dispersant solution for cement to which an antifoaming agent is added can be prepared in advance. However, the defoaming agent is generally difficult to dissolve in water, and especially when the solid content concentration of the dispersant aqueous solution for cement is 10% or more, the solubility further decreases, and in this case, the defoaming effect decreases. The present inventors have already found that a uniform aqueous solution using a specific nonionic surfactant exhibits low foaming properties (Japanese Patent Laid-Open No. 58-173142), but it was added to a cement slurry. In order to achieve the purpose of suppressing the foaming, there has been a problem that a large amount of nonionic surface active agents must be used.

[0004]

Under the circumstances described above, the present invention has variously studied to obtain a dispersant for cement which has an effect of suppressing foaming of cement slurry as compared with the prior art, and as a result, silicone oil has been obtained. It was found that a sufficient defoaming effect can be obtained by using in combination, and the present invention has been completed.

[0005]

According to the present invention, 100 parts by weight of an alkali metal salt or ammonium salt of a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid anhydride is thus obtained. Provided is a dispersant for cement containing 0.3 to 10 parts by weight of a nonionic surfactant having an HLB value of 12 or more per part and 0.01 to 1 part by weight of silicone oil.

The first component of the dispersant for cement of the present invention is
It is prepared from a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid anhydride. The vinyl-based monomer used may have a polar group such as an ester group or an ether group as long as it has 4 to 10 carbon atoms, and examples thereof include an olefin compound and an aromatic vinyl compound. Specific examples of the olefin compound include butene-1, butene-2, isobutylene, pentene-1,
Pentene-2,2-methyl-butene-1,2-methyl-
Butene-2, cyclopentene, 4-methyl-pentene-
1, hexene-1, cyclohexene, diisobutylene,
Octene-1 and the like; examples of the aromatic vinyl compound include styrene and α-methylstyrene. Examples of those having a polar group such as an ether group and an ester group include vinyl ether and vinyl acetate. Among them, an olefin compound having 4 to 5 carbon atoms is prized. Further, if necessary, two or more vinyl-based monomers may be used in combination.

Examples of the α, β-unsaturated dicarboxylic acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride and the like. Among them, maleic anhydride is most favored in terms of reactivity, quality and economy.

The copolymer composed of these two components usually has a number average molecular weight of 500 to 100,000, preferably 1,000 to 10,000, and a vinyl monomer component of 20 to 80 mol%. It is composed of an α, β-unsaturated dicarboxylic acid anhydride component of 80 to 20 mol%.

The alkali metal salt or ammonium salt of the copolymer usually has 4 carbon atoms in the presence of a radical initiator.
Synthesizing a copolymer of vinyl monomer of 10 to α, β-unsaturated dicarboxylic acid anhydride, and then hydrolyzing the acid anhydride group in the copolymer in the presence of a base according to a conventional method Manufactured by. At this time, the degree of neutralization of the salt of the produced copolymer is 20 to 100%. At this time, the amount of the base used is usually 0.1 per 1 mol of the acid anhydride group in the copolymer.
It is 8 to 2 mol, preferably 1 to 1.8 mol. The type of salt formed is an alkali metal salt such as sodium salt or potassium salt, or an ammonium salt. In the case of a polyvalent metal salt of divalent or higher, the foaming property is large,
Moreover, it is not preferable because it is inferior in stability. Furthermore, it is also possible to introduce an ester group, an amide group, or an imide group into a part of the α, β-unsaturated dicarboxylic acid anhydride portion in the copolymer. In addition, the salt of such a copolymer is prepared in advance from α, β-
It can be produced by hydrolyzing an unsaturated dicarboxylic acid anhydride in the presence of a base, and then copolymerizing this with a vinyl-based monomer.

The second component of the cement dispersant of the present invention is
A nonionic surfactant having an HLB value of 12 or more, preferably 13 to 20. Specifically, polyoxyethylene-polyoxypropylene adduct, ethylenediamine polyoxypropylene-polyoxyethylene adduct, polyhydric alcohol ester polyoxyethylene adduct, polyethylene glycol monoester, polyethylene glycol diester, higher alcohol polyoxyethylene. Among the nonionic surfactants such as adducts, alkylphenol polyoxyethylene adducts and acetylene glycol polyoxyethylene adducts, those having an HLB value of 12 or more are used in the present invention. If the HLB value is less than 12, the solubility of the nonionic surfactant in water decreases, which is not preferable. Further, when the HLB value exceeds 20, the foaming property of the nonionic surfactant becomes large, which is not preferable. Among these nonionic surfactants, acetylene glycol polyoxyethylene adducts and the like are most favored in terms of quality, solubility in water and the like. Such nonionic surfactants are usually used as O / W emulsifiers in the fields of detergents, foaming agents, solubilizing agents for oily water, etc., and are also effective as auxiliary agents for foaming agents. Are known (see, for example, JP-A No. 54-50027), but surprisingly, the present invention exerts a function as an antifoaming agent.

The nonionic surfactant has 4 carbon atoms.
0.3 to 10 parts by weight, preferably 0.5 to 3 parts by weight, per 100 parts by weight of the alkali metal salt or ammonium salt of the copolymer of vinyl monomer of 10 to α, β-unsaturated dicarboxylic acid anhydride. Used in part ratio. At this time, if the amount used is less than 0.3 parts by weight, the defoaming effect is poor, and conversely 1
When it exceeds 0 parts by weight, the foaming property which is the original property of the nonionic surfactant is increased and the defoaming effect is not exhibited.

The third component of the cement dispersant of the present invention is
Has a polyorganosiloxane structure and a viscosity of 100 to 1
It is 10,000 centistokes silicone oil. Specific examples of the silicone oil include dimethyl silicone oil in which all the alkyl groups bonded to the silicon atom are methyl groups; phenylmethyl silicone oil in which a part of the methyl group is substituted with a phenyl group; Methyl hydrogen silicone oil in which one is a methyl group and the other one is substituted with hydrogen; polyoxyalkylene-modified siloxane which is a copolymer of methylsiloxane and oxyalkylene; amino-modified silicone oil; fluoropropyl-modified silicone oil Etc.

The silicone oil is a silicone oil as it is; an oil compound type in which fine powder of silica, alumina, etc. is dispersed in the silicone oil; a silicone oil or an oil compound is a hydrocarbon type, an aromatic type,
Any form such as a solution type dissolved in a chlorine-based solvent or the like; an emulsion type in which an oil compound is made into an oil-in-water type (O / W type) with an emulsifier can be used. In particular, a polyoxyalkylene-modified siloxane has a molecular structure of a linear or branched block copolymer of dimethylsiloxane and oxyalkylene; a side chain in which a polyoxyalkylene group is introduced as a side chain into the main chain of polydimethylsiloxane. Type copolymers and the like, which are called self-emulsifying silicone oils, are easily emulsified in water and can be preferably used.

The silicone oil has 4 to 10 carbon atoms.
0.001 to 1 part by weight, preferably 0.01 to 0.2 part by weight, based on 100 parts by weight of the alkali metal salt or ammonium salt of the copolymer of the vinyl monomer and α, β-unsaturated dicarboxylic acid anhydride. Part, more preferably 0.03 to
Used in a proportion of 0.15 parts by weight. At this time, if the amount used is less than 0.001 part by weight, the defoaming effect is poor, and conversely, if it exceeds 1 part by weight, the compatibility of the copolymer with salts and surfactants decreases, which is not preferable. ..

The cement dispersant of the present invention is usually used as an aqueous solution having a solid content concentration of 5 to 50% by weight, preferably 10 to 40% by weight.

[0016]

The present invention will be described below with reference to examples. In the examples, parts and% are based on weight unless otherwise specified.

(Example 1) A 40% aqueous solution of a sodium salt (60% neutralization degree) of a copolymer (50 mol% isoamylene-50 mol% maleic anhydride) synthesized by radical polymerization (number average molecular weight 6000) was prepared. , An acetylene glycol polyoxyethylene adduct (HLB = 13) and a (dimethylsiloxane-oxyalkylene) block copolymer in an amount of 1 part by weight shown in Table 1 were added to prepare a cement dispersant aqueous solution. The compatibility of the combination, the surfactant and the silicone oil was evaluated. In addition, a cement dispersion test was conducted to evaluate the defoaming effect on the cement slurry. (Compatibility test) The cloud point of the aqueous dispersant solution for cement was measured. (Defoaming test) To a mixture of ordinary Portland cement and water of the same weight, 0.2% of a dispersant aqueous solution for cement was added as a solid content to the cement, and the generated foam was generated after stirring for 1 minute with a mixer. Time to disappear (foaming time)
Was measured. The results are shown in Table 1.

[0018]

[Table 1]

From Table 1, the aqueous solution of the cement dispersant of the present invention shows good compatibility without lowering the cloud point, and the amount of the nonionic surfactant used is smaller than that in the prior art. It can be seen that an excellent defoaming effect on the cement slurry can be obtained.

(Example 2) Instead of the (isoamylene-maleic anhydride) copolymer, (styrene 50 mol% -maleic anhydride 50 mol%) copolymer (number average molecular weight 600)
The same experiment as in Example 1 was carried out except that a 40% aqueous solution of sodium salt of 0) (neutralization degree 70%) was used. The results are shown in Table 2.
Shown in.

[0021]

[Table 2]

Example 3 The same experiment as in Example 1 was carried out except that a side chain type copolymer having a main chain of polydimethylsiloxane and a polyoxyalkylene group as a side chain was used as the silicone oil. The results are shown in Table 3.

[0023]

[Table 3]

(Embodiment 4) Different HLB (HLB = 1)
3, 16) The same experiment as in Example 3 was performed except that two kinds of nonionic surfactants were used in combination. The results are shown in Table 4.

[0025]

[Table 4]

[0026]

As described above, according to the present invention, a dispersant for cement having an excellent defoaming effect on the cement slurry can be obtained by using a small amount of nonionic surfactant as compared with the prior art.

Claims (1)

[Claims] 1. An alkali metal salt or ammonium salt of a copolymer of a vinyl monomer having 4 to 10 carbon atoms and an α, β-unsaturated dicarboxylic acid anhydride, 100 parts by weight, HLB.
A dispersant for cement containing 0.3 to 10 parts by weight of a nonionic surfactant having a value of 12 or more and 0.001 to 1 part by weight of silicone oil.