HK1091195B - Cement dispersant and concrete composition containing the dispersant - Google Patents

Description

Cement dispersant and concrete composition containing the same

Technical Field

The present invention relates to a cement dispersant and a concrete composition containing the dispersant. More particularly, the present invention relates to a cement dispersant which has excellent dispersibility, slump flow persistence and strength realization after hardening in the field of a low water/binder ratio by simultaneously containing a polyamide polyamine group, a long-chain polyalkylene glycol group and a short-chain polyalkylene glycol group in one copolymer molecule, and is particularly suitable for ultra-high performance concrete having reduced high concrete slurry viscosity peculiar to the field and good workability, and a concrete composition such as an ultra-high performance concrete composition containing the dispersant.

Background

Heretofore, as a cement dispersant, a melamine sulfonate, a lignin sulfonate, a copolymer of an olefin and maleic acid, a publicly known polycarboxylic acid dispersant, and the like have been used. However, due to the recent industrial background that buildings are moving to urban areas, JIS regarding strength is modified, and the like, buildings required to have high strength are increasing. In order to obtain a high-strength structure, the number of cases where concrete components such as low-heat cement and silica cement are used, which are different from conventional common structures, is increasing, and thus there is a high demand for a polycarboxylic acid cement dispersant to be used therein. As main requirements, the following aspects can be cited: it is required to satisfy the requirements of excellent water-reducing property, slump flow persistence, and post-hardening strength achievement against setting delay due to a large addition amount in the case of a low water/cement ratio (hereinafter, simply referred to as W/C. and water/binder ratio simply referred to as W/B), and also to satisfy the requirements of excellent concrete slurry viscosity lowering property and the like in order to solve the problems that the construction is hindered by the peculiar concrete viscosity due to the low W/C.

In order to solve these problems, various polycarboxylic acid cement dispersants have been proposed. For example, patent document 1 discloses a copolymer of a (meth) acrylate salt, a (meth) acryloyl sulfonate salt, a monoacrylate of a polyethylene glycol alkyl ether, or a monoacrylate of a polypropylene glycol alkyl ether. Patent document 2 discloses a cement dispersant containing polyalkylene glycol chains having different chain lengths in one copolymer molecule, and the cement dispersant is evaluated as a material satisfying both the requirements of viscosity reduction under high shear and the inhibition of setting delay, using a flow value at a W/C of 29.0% and a concrete spreading rate (sec) at 50 cm. Patent document 3 discloses a cement dispersant containing polyalkylene glycol chains having different chain lengths in one copolymer molecule, and evaluates the flow value at a W/C of 25%. Similarly, patent document 4 proposes a cement dispersant containing polyalkylene glycol chains having different chain lengths in one copolymer molecule, and evaluates the flow value and the air amount thereof with time when the W/C is 40%. Patent documents 5, 6, and 7 disclose cement dispersants produced by the following methods: a polymerization method in which the molar ratio of monomers containing a long-chain polyalkylene glycol group and a short-chain polyalkylene glycol group during polymerization is changed at least once during the reaction.

Further, patent documents 8 and 9 are cited as documents disclosing a cement dispersant containing a polyamidopolyamine-based monomer which is a feature of the present invention in a copolymer. However, since the dispersant used for the above-mentioned high-strength structure should satisfy high requirements, it is desired to provide a dispersant which can satisfy more sophisticated conditions.

Patent document 1: japanese patent laid-open publication No. Hei 1-226757 (page 1, pages 3-6)

Patent document 2: japanese patent laid-open No. 3285526 (pages 2-5, pages 7-9)

Patent document 3: japanese patent laid-open publication No. 9-286645 (pages 2-6)

Patent document 4: japanese patent laid-open No. 3184698 (pages 1-8)

Patent document 5: japanese patent laid-open publication No. 2002-003258 (pages 2-6, pages 8-11)

Patent document 6: japanese patent laid-open publication No. 2002-179448 (pages 2-5, pages 7-17)

Patent document 7: japanese patent laid-open publication No. 2002-179449 (pages 2-5, pages 9-20)

Patent document 8: japanese patent No. 3235002 (pages 1-8)

Patent document 9: japanese patent laid-open No. 3336456 (pages 1-11)

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of such circumstances, and is intended to solve the problems of the conventional cement dispersants. That is, the problem to be solved is to provide an excellent cement dispersant which can satisfy water-reducing ability, slump flow persistence and quick achievement of strength in a balanced manner in a low water/binder ratio range and particularly can reduce the high viscosity of a concrete slurry, and a concrete composition containing the dispersant.

Means for solving the problems

The present inventors have conducted extensive studies to solve the above-mentioned problems, and as a result, have found that a copolymer containing a polyalkylene polyamide-based monomer, a long-chain polyalkylene glycol-based monomer, a short-chain polyalkylene glycol-based monomer and a (meth) acrylic acid-based monomer per molecule of the copolymer can achieve desired effects, thereby completing the present invention.

That is, the present invention relates to a cement dispersant containing a water-soluble amphoteric copolymer obtained by copolymerizing a monomer mixture containing, as main monomer components:

at least one compound (compound A) obtained by adding 0 to 8 moles of alkylene oxide having 2 to 4 carbon atoms to 1 equivalent of amino residue of a polyamidopolyamine obtained by condensing 0.5 to 0.95 mole of an ester of a polyalkylenepolyamine having 1.0 mole of a dibasic acid or a dibasic acid and a lower alcohol having 1 to 4 carbon atoms and 0.05 to 0.70 mole of acrylic acid or methacrylic acid or an ester of an acrylic acid or methacrylic acid and a lower alcohol having 1 to 4 carbon atoms (compound A), and

at least one compound (compound B) represented by the general formula (1):

(in the formula, R¹Represents a hydrogen atom or a methyl group, M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group or an alkanolammonium group), and

at least one compound (compound C) represented by the general formula (2):

(in the formula, R²Represents a hydrogen atom or a methyl group, R³Represents an alkylene group having 2 to 4 carbon atoms, R⁴Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and m is the number of moles of polyalkylene glycol added and represents an integer of 1 to 35), and

at least one compound D represented by the general formula (3):

(in the formula, R⁵Represents a hydrogen atom or a methyl group, R⁶Represents an alkylene group having 2 to 4 carbon atoms, R⁷Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is the number of addition mols of polyalkylene glycol and represents an integer of 40 to 100).

The present invention also relates to the above-described cement dispersant of the present invention which is particularly suitable for use in the formulation of ultra-high performance concrete compositions. The present invention also relates to a concrete composition comprising the cement dispersant of the present invention and the concrete composition particularly suitable for ultrahigh performance concrete. In the present specification, the term "ultra-high performance concrete" refers to a concrete which is formed in a good condition at a low W/C.

As described above, the compound a used in the present invention is a compound obtained by adding a specific amount of alkylene oxide (compound d) to a polyamide polyamine obtained by condensing a polyalkylene polyamine (compound a), a dibasic acid or an ester of a dibasic acid and a lower alcohol having 1 to 4 carbon atoms (compound b), acrylic acid or methacrylic acid, or an ester of acrylic acid or methacrylic acid and a lower alcohol having 1 to 4 carbon atoms (compound c) at a specific ratio.

Examples of the polyalkylene polyamine compound a include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine, tripropylenetetramine, and tetrapropylenepentamine, but diethylenetriamine and triethylenetetramine are preferable from the viewpoint of the effect and the economical efficiency.

Examples of the dibasic acid and the lower alcohol ester thereof having 1 to 4 carbon atoms of the compound b include malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid, pimelic acid, phthalic acid, azelaic acid, sebacic acid, and lower alcohol esters thereof having 1 to 4 carbon atoms, such as methanol, ethanol, propanol, butanol, or isomers thereof, if any.

Among these, adipic acid is most preferable from the viewpoint of efficiency and economy.

Examples of the compound c, acrylic acid or methacrylic acid, and a lower alcohol ester thereof having 1 to 4 carbon atoms include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, and the like.

The polyamide polyamine composed of the three components of the above-mentioned compounds a, b and c can be conveniently obtained by a known polycondensation technique. The alkylene oxide having 2 to 4 carbon atoms as the compound d to be added to the amino residue of the polyamide polyamine means ethylene oxide, propylene oxide or butylene oxide. These alkylene oxides may be used singly or in combination of two or more.

The polycondensation reaction of the compounds a, b and c in the preparation of the polyamide polyamine may be, for example, a two-step reaction method in which only the compound a and the compound b are first subjected to polycondensation, and then the compound c as a monobasic acid is added to further perform polycondensation, or a one-step reaction method in which the compounds a, b and c are simultaneously mixed from the beginning to perform polycondensation. However, in any of the methods, since the polycondensation reaction, that is, the amidation reaction and the amide exchange reaction are simultaneously carried out, it is considered that the same result is obtained when the acrylic acid residue or the methacrylic acid residue derived from the compound c is finally positioned at the end of the polyamide chain.

Next, the reaction molar ratio of the above three components constituting the polyamide polyamine will be described. The reaction ratio of the compound b (dibasic acid or ester thereof) is 0.5 to 0.95 mol based on 1.0 mol of the compound a (polyalkylene polyamine). By reacting at a molar ratio within this range, the polycondensate of the compound a and the compound b is a polyamide having a chain length within a certain range, which is formed by polycondensation at an average ratio of (2 moles of polyalkylene polyamine: 1 mole of dibasic acid) to (20 moles of polyalkylene polyamine: 19 moles of dibasic acid), so that the dispersant formed therefrom can exhibit high water-reducing ability and slump flow persistence. When the chain length of the polyamide is shorter (when the reaction ratio is less than 0.5 mol), a certain polyamide polyamine structure cannot be obtained. Further, when the chain length of the polyamide is longer (when the reaction ratio exceeds 0.95 mol), the water-reducing property is lowered, which is not preferable.

The polyamide polyamine of the present invention contains acrylic acid residues or methacrylic acid residues in an amount of 0.10 mol [ when a: b: c is 1.0: 0.5: 0.05 (mol) ] to 14 mol [ when a: b: c is 1.0: 0.95: 0.70 (mol) ] per molecule, but is preferably in the range of 0.5 to 2.0 mol from the viewpoint of effect. If this value is less than 0.5 mol (for example, if the molar ratio of compound c to compound a is less than 0.25 when a: b is 1.0: 0.5), the composition ratio of compound a thus formed in the final copolymer is low, and the performance as a cement dispersant is markedly lowered. On the other hand, if it exceeds 2.0 mol (for example, if the molar ratio of the compound c to the compound a exceeds 0.10 when a: b is 1.0: 0.95), the copolymer will form too many three-dimensional structures, and sufficient effects cannot be obtained.

In particular, when the molar number of the dibasic acid or the ester of the dibasic acid and the lower alcohol having 1 to 4 carbon atoms is represented by x and the molar number of the acrylic acid or the methacrylic acid or the ester of the acrylic acid or the methacrylic acid and the lower alcohol having 1 to 4 carbon atoms is represented by y, the molar relationship between the two is preferably 0.6 < y/(1-x) < 1.4, based on 1.0 mole of the polyalkylene polyamine. When y/(1-x) is 0.6. gtoreq.y/(1-x), the copolymer does not contain a sufficient amount of the polyamidopolyamine monomer, and when y/(1-x) is 1.4 or more, the copolymer contains a large amount of the diamide polyamidopolyamine monomer having a reactive group at both ends, which results in the increase in molecular weight of the polymer and the formation of gel, and the effect of reducing the viscosity cannot be sufficiently achieved.

The amount of alkylene oxide added to the polyamidopolyamine is 0 to 8 mol per 1 equivalent of the amino residue of the polyamidopolyamine. When the amount exceeds 8 mol, the molecular weight of the compound A becomes large, and the cation equivalent weight is lowered, so that the effect as the amphoteric polymer of the present invention cannot be sufficiently obtained. In the present invention, the addition of the alkylene oxide is preferably carried out, and the amount thereof is preferably 0.5 to 6.0 mol, particularly preferably 1.0 to 5.5 mol, based on 1 equivalent of the amino residue of the polyamide polyamine.

As the compound B used in the present invention, acrylic acid or methacrylic acid or their sodium, potassium, ammonium, monoethanolamine, diethanolamine, or triethanolamine salts can be cited, but acrylic acid or methacrylic acid is preferable from the viewpoint of performance and economy.

As the form of the compound B which is finally incorporated into the copolymer, an acid and/or a (partially or completely) neutralized salt of sodium, potassium or ammonium is preferable from the viewpoint of water solubility. For neutralization, neutralization may be carried out after synthesis in the acid form, or may be carried out as a salt form before polymerization.

Examples of the compound C and the compound D used in the present invention include (meth) acrylate of methoxypolyethylene glycol, (meth) acrylate of ethoxypolyethylene glycol, (meth) acrylate of ethylene oxide/propylene oxide adduct of methanol, mono (meth) acrylate of polyalkylene glycol, and the like.

The number of alkylene oxide addition moles of the compound C used in the present invention is 1 to 35 moles. When the amount is 1 or less, the water solubility of the polymer is remarkably decreased, and when the amount is 35 or more, the slump flow persistence is deteriorated.

The number of moles of alkylene oxide added to the compound D used in the present invention is 40 to 100. The water-reducing property is poor at 40 or less, and the slump flow persistence is remarkably decreased at more than 100.

The copolymer as the cement dispersant of the present invention may further contain a copolymerizable monomer other than compound A, B, C, D. The following known monomers can be mentioned as examples of such monomers. These monomers are (non) aqueous monomers: methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, styrene, and the like, anionic monomers: itaconic acid, maleic acid (anhydride), vinylsulfonic acid, styrenesulfonic acid, and the like, amide-based monomers: acrylamide, alkylene oxide adduct of acrylamide, etc., polyalkylene glycol monomer: alkylene oxide adducts of allyl alcohol, monoesters or diesters of polyalkylene glycols with maleic anhydride, esters of polyalkylene glycols with itaconic acid, and the like.

The blending ratio of the other copolymerizable monomer is 30% by weight or less, preferably 20% by weight or less, and more preferably 10% by weight or less of the total monomer added.

The compounding ratio of the compound A, the compound B, the compound C and the compound D used in the present invention is 5 to 25% by weight, 5 to 30% by weight, 5 to 40% by weight and 20 to 80% by weight based on 100% by weight in total, and by selecting an appropriate amount of each compound within this range, the balance of water-reducing property, slump flow persistence, quick achievement of strength and reduction in concrete viscosity can be achieved, but this effect cannot be achieved outside this range.

The method for producing the cement dispersant of the present invention is not particularly limited, and for example, a known polymerization method such as solution polymerization or bulk polymerization using a polymerization initiator can be used.

The solution polymerization method may be carried out either batchwise or continuously, and examples of the solvent used therein include water; alcohols such as methanol, ethanol, and isopropanol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane, and n-hexane; ester compounds such as ethyl acetate; ketone compounds such as acetone and methyl ethyl ketone; cyclic ether compounds such as tetrahydrofuran and dioxane, and the like, are preferably used in view of solubility of the raw material monomer and the copolymer to be formed, and at least one of water and a lower alcohol having 1 to 4 carbon atoms is preferably used, and water is more preferably used as the solvent.

In the case of aqueous solution polymerization, as the radical polymerization initiator, water-soluble polymerization initiators such as persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; azo amidine compounds such as 2, 2 ' -azobis-2-methylpropionamidine hydrochloride, cyclic azo amidine compounds such as 2, 2 ' -azobis-2- (2-imidazolin-2-yl) propane hydrochloride, water-soluble azo initiators for azonitrile compounds such as 2-carbamoylazoisobutyronitrile, and in this case, alkali metal sulfites such as sodium bisulfite, Fe (II) salts such as pyrosulfites, sodium hypophosphite, Mohr's salts, dihydrate of sodium hydroxymethanesulfonate, hydroxylamine salts, thiourea, L-ascorbic acid (salt), isoascorbic acid (salt) and the like may be used in combination.

In addition, in solution polymerization using a lower alcohol, an aromatic or aliphatic hydrocarbon, an ester compound or a ketone compound as a solvent, a peroxide such as benzoyl peroxide, lauroyl peroxide or sodium peroxide; hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; a radical initiator such as azo compounds such as azobisisobutyronitrile and the like. In addition, an accelerator such as an amine compound may be used in combination. When a water-lower alcohol mixed solvent is used, the above-mentioned various radical polymerization initiators or a combination of a radical polymerization initiator and an accelerator can be appropriately selected and used.

In the case of bulk polymerization, as a radical polymerization initiator, a peroxide such as benzoyl peroxide, lauroyl peroxide, or sodium peroxide; hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; azo compounds such as azobisisobutyronitrile.

The reaction temperature in the copolymerization is not particularly limited, and for example, a reaction temperature in the range of 30 to 95 ℃ is suitable when persulfate is used as an initiator.

Chain transfer agents may be used in the copolymerization. As the chain transfer agent, a thiol chain transfer agent such as mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, or 2-mercaptoethanesulfonic acid may be used, or two or more kinds of chain transfer agents may be used in combination.

The polymerization time in the copolymerization is not particularly limited, and for example, 1 to 10 hours is suitable, preferably 1 to 8 hours, and more preferably 1.5 to 6 hours. If the polymerization time is shorter or longer than this range, the polymerization rate will be low and the productivity will be poor, and therefore it is not preferable.

The method of dropping the monomers during the copolymerization is not particularly limited, and examples thereof include a method of adding a part or all of the monomers to a reaction vessel and dropping an initiator, a method of adding one or more monomers to a reaction vessel and dropping another monomer, an initiator, a chain transfer agent, and the like, a method of dropping a monomer mixture, a radical polymerization initiator, and a chain transfer agent separately, and a method of dropping a mixture of each monomer and a chain transfer agent separately and a method of dropping a radical polymerization initiator separately, as disclosed in Japanese patent application No. 3235002 and Japanese patent application No. 3336456.

The molecular weight of the copolymer obtained in the present invention is not particularly limited, and the weight average molecular weight (gel permeation chromatography, in terms of polyethylene glycol) may be 3,000 to 500,000, and if it is outside this range, the dispersibility is poor.

The water-soluble amphoteric copolymer of the present invention thus formed has excellent water-reducing ability, slump flow persistence and quickness of strength realization in the range of low water/binder, and particularly has an effect of lowering high concrete viscosity, and can exhibit performances which could not be achieved by conventional or proposed cement dispersants, when used as a cement dispersant. It is believed that this effect is caused by the copolymer having a carboxyl group (anionic group), a polyalkylene polyamide group (cationic group) and a nonionic hydrophilic group consisting of a long-chain and short-chain polyalkylene glycol group in the molecular structure. The use of such a copolymer having a specific structure is the basis of the present invention. In particular, the synergistic effect is produced by the electric action of the cationic group moiety of the above polyamide polyamine group, the hydrophilic action of the hydroxyl group, and the effective steric hindrance effect of the long-chain polyalkylene glycol by the appropriate combination of the short-chain polyalkylene glycol group and the long-chain polyalkylene glycol group, and the cement dispersant can be effectively adsorbed on the inorganic material (cement particles) even in the presence of a small amount of water in the low water/binder ratio range, and the presence of the short-chain polyalkylene glycol group achieves the object of allowing the long-chain polyalkylene glycol group to exert a good effective action, resulting in the effect of the present invention. The effective action of the cement dispersant is to reduce the amount of the cement dispersant to be added, and to reduce the setting retardation due to the excessive addition of the cement dispersant, thereby to attain the rapid achievement of the strength. The above mechanism can be presumed for the effect exerted by the cement dispersant of the present invention, but it cannot be said that the effect is exerted.

Effects of the invention

As described above in detail, the cement dispersant of the present invention has high water-reducing ability and excellent slump flow retention in the range of low water/binder, and has a rapid strength realization property and a specific concrete viscosity-reducing effect, and thus is suitable as a dispersant for ultra-high performance concrete. The water-soluble amphoteric copolymer of the present invention is suitable for use as a high-performance AE water reducing agent or the like. The concrete composition containing the cement dispersant of the present invention having the above excellent characteristics has excellent water-reducing properties, slump flow persistence, strength realization properties and concrete viscosity reducing properties, and thus has excellent workability on site. Therefore, the present invention provides a dispersant or water reducing agent expected in the art, and makes a great contribution to the art.

Best Mode for Carrying Out The Invention

The addition range of the cement dispersant composed of the water-soluble amphoteric copolymer of the present invention to the binder containing the concrete material is about 0.1 to 1.8% in terms of solid content. In particular, when the water/binder ratio is as low as 20% or less, the amount added is often more than 1.0%. That is, in order to obtain water-reducing property and slump flow durability, the larger the amount of addition, the better, but the larger the amount of addition, the more the addition, the retardation of coagulation is caused, and in the worst case, hardening failure is caused. The use method may be the same as that of a conventional cement dispersant, and the raw liquid may be added at the time of kneading concrete or may be added after diluting the raw liquid with kneading water in advance. Or after the concrete or mortar is kneaded, the mixture is added and kneaded uniformly again. The present invention also provides a concrete composition containing the above cement dispersant of the present invention.

The components other than the cement dispersant are conventionally used as concrete components, and examples thereof include cement such as ordinary portland cement, early strength portland cement, low heat and medium heat portland cement, slag cement, silica powder cement, VKC-100SF, etc., aggregate such as fine aggregate and coarse aggregate, and mixed materials such as silica powder, fly ash, calcium carbonate powder, blast furnace slag powder, expanding material and water.

In addition, a conventional cement dispersant other than the cement dispersant of the present invention, an air-entraining agent, an antifoaming agent, a setting retarder, an accelerator, a thickener, a separation inhibitor, a shrinkage inhibitor, a peeling agent, and the like can be appropriately blended. The compounding ratio of these components can be determined conveniently according to the kind of the selected components and the purpose of use.

The dispersant of the present invention has excellent water-reducing properties, slump flow retention properties, and strength-realizing rapidity, particularly, a property of reducing the viscosity of a high concrete slurry in a range of a low water/binder ratio, but may be used in a range of a normal water/binder ratio. For example, the cement dispersant of the present invention can be used alone or in combination with a general-purpose cement dispersant for pre-casting applications, and can be used in applications within a range of a usual water/binder ratio. In these cases, it is inevitable that the addition of the cement dispersant of the present invention provides the effects of improving the initial water-reducing property and achieving early strength.

The cement dispersant can be combined with a common cement dispersant according to the proportion of 1-99/99-1. The usual mix ratio varies depending on the water/binder ratio and its use.

The conventional cement dispersant which can be combined with the cement dispersant of the present invention is not particularly limited, and known cement dispersants can be exemplified. Examples of the polycarboxylic acid-based dispersant include lignosulfonate, a salt of a condensate of naphthalenesulfonic acid and formalin, a condensate salt of melaminesulfonic acid and formalin, and a condensate salt of polystyrenesulfonic acid, and examples of the polycarboxylic acid-based dispersant include a copolymer of polyethylene glycol monoallyl ether and unsaturated dicarboxylic acid as disclosed in Japanese patent publication No. 58-383380, a copolymer of polyalkylene glycol mono (meth) acrylic acid and (meth) acrylic acid as disclosed in Japanese patent publication No. 59-18338, a copolymer of a monomer having a sulfonic acid group at the terminal thereof, polyalkylene glycol mono (meth) acrylate and (meth) acrylic acid as disclosed in Japanese patent publication No. 2628486, a copolymer of polyalkylene glycol mono (meth) acrylate and (meth) acrylic acid as disclosed in Japanese patent publication No. 2774445, a copolymer of polyalkylene glycol mono (meth) acrylate and (meth) acrylic acid as disclosed in Japanese patent publication No. 3235002 having a polyamidopolyamine-based monomer, Japanese patent No. 3336456 and the like.

In order to obtain a concrete composition in a good state, the above-mentioned air-entraining agent, setting retarder, accelerator, separation inhibitor, thickener and the like can be usually blended. In the present specification, a cement dispersant and a preparation containing the dispersant are referred to as other additives for mortar and concrete.

Accordingly, the present invention also provides an admixture for mortar and concrete which is a composition comprising the cement dispersant of the present invention and the above-mentioned other additives for mortar and concrete, and a concrete composition containing the admixture for mortar and concrete.

Additives for mortar and concrete other than cement dispersants have been exemplified above, and these are air-entraining agents, defoaming agents, setting retarders, accelerators, tackifiers, separation preventing agents and the like. These components may be added to the cement dispersant of the present invention before the concrete slurry is formed, or may be added to the mixing water.

Specific examples of such other additives for mortar and concrete include (1) anionic air-entraining agents, (2) nonionic air-entraining agents, and (3) amphoteric air-entraining agents composed of anions and cations. Examples of (1) the anionic air-entraining agent include higher alcohol (alkoxylated) sulfate, resin soap, and higher alcohol (alkoxylated) phosphate, examples of (2) the nonionic air-entraining agent include polyalkylene glycol, alkylene oxide adduct of higher alcohol, ester of fatty acid and polyalkylene glycol, and alkylene oxide adduct of sugar alcohol fatty acid ester, and examples of (3) the amphoteric air-entraining agent composed of anion and cation include alkyl betaine type, alkylamide betaine type, and amino acid amphoteric activators, but are not limited to these.

As concrete examples of the defoaming agent as another additive for mortar and concrete, there can be mentioned (1) an active agent type defoaming agent, (2) a silicone type defoaming agent and (3) a mineral oil type defoaming agent, and as the (1) active agent type defoaming agent, there are exemplified polyalkylene glycol, an alkylene oxide adduct of higher alcohol, an ester of an alkylene oxide adduct of higher alcohol and a fatty acid, an ester of polyalkylene glycol and a fatty acid, etc., as the (2) silicone type defoaming agent, dimethyl silicone, a silicone emulsion, etc., and as the (3) mineral oil type defoaming agent, mineral oil emulsion, paraffin emulsion, higher alcohol emulsion, etc.

Specific examples of the setting retarder as another additive for mortar and concrete include (1) inorganic setting retarders: phosphates, fluorides of silicon, zinc oxide, zinc carbonate, zinc chloride, zinc oxide, copper hydroxide, magnesium salts, borax, boron oxide, (2) organic coagulation retarders: phosphonic acid derivatives, saccharides or derivatives thereof, hydroxycarboxylic acid salts, and lignosulfonic acid salts, and if more specifically exemplified, phosphonic acid derivatives are exemplified: amino tri (methylene phosphonic acid), amino tri (methylene phosphonic acid) pentasodium salt, 1-hydroxyethylidene-1, 1-diphosphonic acid, ethylene diamino tetra (methylene phosphonic acid), diethylene triamine penta (methylene phosphonic acid) and phosphonic acids and derivatives of alkali metal salts, alkaline earth metal salts, sugars: sucrose, maltose, raffinose, lactose, glucose, fructose, mannose, arabinose, xylose, アビト - ス, ribose, hydroxycarboxylate: gluconic acid, citric acid, glucoheptonic acid, malic acid, tartaric acid, their alkali metal salts, alkaline earth metal salts. The additive is preferably added in an amount of 0.1 to 20 parts by weight based on the binder such as cement.

Examples of the accelerator as another additive for mortar and concrete include inorganic accelerators represented by calcium chloride, calcium nitrate, and calcium nitrite, and organic accelerators represented by alkanolamines.

Examples of the thickener/separation inhibitor as another additive for mortar and concrete include (1) a cellulose-based water-soluble polymer: cellulose ether (MC, etc.), (2) polyacrylamide-based water-soluble polymer: polyacrylamide, (3) biopolymer: カ - ドラン, Welan gum, (4) nonionic tackifier: fatty acid diesters of polyalkylene glycols, urethane condensates of polyalkylene glycols, and the like. The preferable mixing ratio of the additive is 0.5-3.0 kg/m relative to the inorganic material³。

Examples

Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1

< Process for producing Compound A-1 >

103g (1.00 mol) of diethylenetriamine and 97.3g (0.67 mol) of adipic acid were charged into a reaction vessel equipped with a stirrer, and stirred and mixed under a nitrogen atmosphere by introducing nitrogen gas. The temperature was raised to 150 ℃ and water produced in the reaction was removed at the same time as the polycondensation, and the reaction was carried out for 20 hours until the acid value became 22. Then, 1.1g of hydroquinone methyl ether and 27.5g (0.32 mol) of methacrylic acid were added thereto, and the mixture was reacted at the same temperature (150 ℃ C.) for 10 hours. Thus, a total of 42g of distilled water from the reaction and 187g of polyamide polyamine (melting point 122 ℃ C., acid value 23) were obtained. The polyamide polyamine was dissolved in 272g of water and the temperature was raised to 50 ℃. Further, 220g (equivalent to 3.0 moles based on the total amount of amino residues including unreacted amino groups) of ethylene oxide was gradually introduced at the same temperature (50 ℃) over 4 hours, and aging was conducted for 2 hours. 680g of Compound A-1 (60% solids) according to the invention were thus obtained.

< method 1 for producing copolymer >

180g of water was added to a reaction vessel equipped with a stirrer, nitrogen was introduced into the reaction vessel to make the inside of the synthesis system a nitrogen atmosphere, and the temperature was raised to 80 ℃. Then, a mixture of 150g of water, 198.2 g of the compound a, 72.0g of methacrylic acid (compound B), 60.9g of short-chain methoxypolyethylene glycol monomethacrylate (compound C, molecular weight 1000) and 183g of long-chain methoxypolyethylene glycol monomethacrylate (compound D, molecular weight 2000) (in the case where compound B is a Na salt, the ratio of compound a to compound B to compound C to compound D is 15 wt%: 23 wt%: 15 wt%: 47 wt%: total 100 wt%) and 66.4g of a 5% thioglycolic acid aqueous solution were added dropwise to the synthesis system over 2 hours, and 123g of a 5% sodium persulfate aqueous solution was added dropwise to the reaction system over 3 hours. Then aged for 2 hours and cooled. Thereafter, the reaction mixture was neutralized with a 48% NaOH aqueous solution to pH 7 to obtain 1,029g of a water-soluble amphoteric copolymer (A), hereinafter referred to as "copolymer of example 1"). The weight average molecular weight of the copolymer (A) was 46,000 as measured by GPC. The measurement conditions were as follows:

column: ohpak SB-803HQ, Ohpak SB-804HQ (manufactured by Showa electric Co., Ltd.)

Eluent: the ratio of 50mM sodium nitrate aqueous solution to acetonitrile is 80: 20

A detector: differential refractometer

Standard curve: polyethylene glycol.

< method 2 for producing copolymer >

180g of water was added to a reaction vessel equipped with a stirrer, nitrogen was introduced into the reaction vessel to make the inside of the synthesis system a nitrogen atmosphere, and the temperature was raised to 80 ℃. Then, a mixture of 150g of water, 198.2 g of the compound a, 72.0g of methacrylic acid (compound B), 60.9g of short-chain methoxypolyethylene glycol monomethacrylate (compound C, molecular weight 1000) and 183g of long-chain methoxypolyethylene glycol monomethacrylate (compound D, molecular weight 2000) (in the case where compound B is a Na salt, the ratio of compound a to compound B to compound C to compound D is 15 wt%/23 wt%/15 wt%/47 wt%, the total being 100 wt%) and 66.4g of a 5% thioglycolic acid aqueous solution were added dropwise to the synthesis system over 2 hours, and 82g of a 5% sodium persulfate aqueous solution was added dropwise to the reaction system over 2 hours. Then, 41g of a 5% aqueous solution of sodium persulfate was added dropwise over 1 hour. After that, the mixture was aged for 2 hours and cooled. Then, the mixture was neutralized with a 48% NaOH aqueous solution to pH 7 to obtain 1,029g of a water-soluble amphoteric copolymer (B)). When the molecular weight was measured by GPC, the weight average molecular weight of the copolymer (B) was 45,000. The measurement conditions were as follows:

column: ohpak SB-803HQ, Ohpak SB-804HQ (manufactured by Showa electric Co., Ltd.)

Eluent: the ratio of 50mM sodium nitrate aqueous solution to acetonitrile is 80: 20

A detector: differential refractometer

Standard curve: polyethylene glycol.

< comparison of copolymers (A) and (B) obtained by production methods 1 and 2>

The results of GPC measurement of the copolymer (A) obtained by the above production method 1 and the copolymer (B) obtained by the above production method 2 were substantially the same, and it was considered that the same compound was obtained.

Examples 2 to 10

Based on the compounds in the proportions shown in Table 1, compounds A-2 to A-6 as polyamide polyamine alkylene oxide adducts were obtained in the same manner as the preparation method of the compound A-1 obtained in example 1. Further, a water-soluble amphoteric copolymer (examples 2 to 10) was obtained by copolymerization in the same manner as in production method 1 of example 1, using compound A, compound B, compound C and compound D in the proportions shown in Table 2 (except that the water content was adjusted so that the final concentration of the obtained copolymer was 40% in terms of solid content).

TABLE 1

Synthesis examples of Compounds A-1 to A-4 1

N.d. indicates that no measurement is possible because dibasic acid esters are used.

1 Components (a) to (d) used for preparing Compound A in the tables correspond to the above-mentioned Compounds a to d, and each numerical value represents a compositional molar ratio

2 diethylene triamine

3 triethylene tetramine

Acid value of condensate (intermediate condensate) of 4 compound a and compound b

Acid value of 5 condensate (final condensate) of Compound a, Compound b and Compound c

TABLE 2

Examples 1 to 10 x 1

The calculation method of the mixture ratio comprises the following steps: to determine the proportions of the monomers in the copolymer obtained, compound B is calculated as a salt.

Example 1 composition calculation example

Compound A-1: 98.2g (solid content: 98.2X 0.6 ═ 58.9),

compound B: 72.0g (solid content: 108 (molecular weight of sodium methacrylate) × 72g/86 (molecular weight of methacrylic acid) ═ 90.4g)

Compound C: 60.9g, Compound D: 183g, 100% solids.

Compound a, compound B, compound C, compound D, 58.9: 90.4: 60.9: 183 (solids) 15 wt.%, 23 wt.%, 15 wt.%, 47 wt.%

Values of compounds a to C in table 1 are parts by weight of the composition based on solid matter.

2 methoxy polyethylene glycol methacrylate (molecular weight 250)

3 methoxy polyethylene glycol methacrylate (molecular weight 1000)

4 methoxy polyethylene glycol acrylate (molecular weight 250)

5 methoxy polyethylene glycol acrylate (molecular weight 1000)

6 methoxy polyethylene glycol methacrylate (molecular weight 2000)

7 ethoxy polyethylene glycol methacrylate (molecular weight 3000)

8 methoxy polyethylene glycol methacrylate (molecular weight 4000)

Comparative examples 1 to 4

Condensation compounds (compound A '-1 to compound A' -4) were synthesized in the same manner as in example 1, except that the reaction ratio of the dibasic acid (x mol) to the polyalkylene polyamine (1.0 mol) and the (meth) acrylic acid (y mol) was not in accordance with the conditions of 0.6 < y/(1-x) < 1.4, i.e., the reaction ratio was within the scope of the present invention. The compounding ratios of the components used in the synthesis examples are shown in table 3. Then, these compounds A '-1 to A' -4 were copolymerized with the compound B, the compound C and the compound D to obtain water-soluble amphoteric copolymers (comparative examples 1 to 4). The compounding ratio of the components used in this synthesis example is shown in table 4.

TABLE 3

Synthesis examples of Compounds A '-1 to A' -4 (control Compounds). 1

1 Components (a) to (d) used for preparing Compound A' in the tables correspond to the above-mentioned Compounds a to d, and each numerical value represents a compositional molar ratio

2 diethylene triamine

3 triethylene tetramine

Acid value of condensate (intermediate condensate) of 4 compound a and compound b

Acid value of 5 condensate (final condensate) of Compound a, Compound b and Compound c

TABLE 4

Comparative examples 1 to 4 x 1

In table 4, the formulations were determined according to the compounding ratio calculation method of table 2.

Values of compound a', compound B and compound C in table 1 are parts by weight of the composition based on solid matter.

2 methoxy polyethylene glycol methacrylate (molecular weight 1000)

3 methoxy polyethylene glycol methacrylate (molecular weight 2000)

Synthesis results of comparative examples 1 to 4

TABLE 5

	Example 1	Comparative example 1	Comparative example 2	Comparative example 3	Comparative example 4
						Polymer state	Homogeneous aqueous solution	Homogeneous aqueous solution	Homogeneous aqueous solution	Gelation	Gelation
GPC discrimination 1	○	○	△	Is not measurable	Is not measurable
						Reaction ratio of Compound A2	1 times of	0.47 times of	1.6 times of	Is not measurable	Is not measurable

1 o … did not see the shoulder in the polymer field. Δ … has a shoulder that can be identified as a peak in the polymer domain.

Ratio of reaction ratio when the reaction ratio of compound a in example 1 was regarded as 1

When the ratio of the number of moles (═ x moles) of the ester of the dibasic acid or dibasic acid and the lower alcohol having 1 to 4 carbon atoms constituting the compound a 'to the number of moles (═ y moles) of the ester of acrylic acid or methacrylic acid or acrylic acid or methacrylic acid and the lower alcohol having 1 to 4 carbon atoms corresponds to 0.6 or more and y/(1-x), the reaction ratio of the compound a' and the water-soluble amphoteric copolymer is extremely low, and when y/(1-x) or more is 1.4, the molecular weight is increased and even gelation is caused.

Comparative examples 5 to 9

Water-soluble amphoteric copolymers having polyalkylene glycol chains of a single chain length were obtained by copolymerizing compounds A-1 to A-3 and A-6 with compound B, compound C or compound D in the following proportions (comparative examples 5 to 9).

TABLE 6

Comparative examples 5 to 9 x 1

In table 6, the formulations were determined according to the compounding ratio calculation method of table 2.

In table 1, values of compound a, compound B, compound C and compound D are parts by weight of the composition based on solid matter.

2 methoxy polyethylene glycol methacrylate (molecular weight 250)

3 methoxy polyethylene glycol methacrylate (molecular weight 1000)

4 methoxy polyethylene glycol methacrylate (molecular weight 2000)

5 methoxy polyethylene glycol methacrylate (molecular weight 4000)

Test example 1: mortar flow test

< preparation of sample >

200g of ordinary portland cement (manufactured by Pacific セメント Co.) and 260g of silica sand No. 6 (manufactured by Japanese プラスタ -Co.) were weighed and subjected to air refining for 90 seconds. Further, 0.448g (based on solid matter) of the copolymer obtained in examples 1 to 10 and comparative examples 5 to 9 was weighed, and the total amount was diluted with water to 80g to obtain kneading water (water/cement ratio: 40%, sand/cement ratio: 130%). The mixture of cement and sand was put into kneading water and mixed for 180 seconds to prepare a mortar. It is important to note that the mixing conditions of the air-mix and mortar are always uniform.

< measurement and measurement results >

The prepared mortar was poured into a phi 50mm × H50mm hollow cylindrical container on an acrylic resin plate, and filled until the upper end of the container was filled. Immediately after filling, the hollow cylindrical container was lifted up in a direction perpendicular to the acrylic resin plate at a constant speed. When the expansion of the mortar completely stopped, the maximum expansion diameter of the mortar and the diameter perpendicular thereto were measured, and the average of these two values was obtained. This operation was carried out immediately after mortar production, after 60 minutes, after 120 minutes. However, when the measurement was performed after 60 minutes and 120 minutes, the mortar container was covered with a plastic cloth to prevent evaporation of water, and after standing, the mortar was mixed for 90 seconds before the measurement and then filled into a hollow container.

TABLE 7

1 water reduction performance:

more than 120 is "O", more than 110 to less than 120 are "Δ", and more than 100 to less than 110 are "X"

Slump flow persistence ×.:

(immediate mortar flow value) - (mortar flow value after 2 hours) | is "O" when less than 25, ". delta" when 25 or more and less than 30, and "X" when 30 or more "

The copolymer of example 1 containing the compound C-2 and the compound D-1 in one copolymer molecule and the copolymer of example 2 containing the compound C-1 and the compound D-1 in one copolymer molecule were superior in water-reducing ability and slump flow durability to the copolymer of comparative example 5 containing the compound D-1 only and the copolymer of comparative example 7 containing the compound C-2 only.

TABLE 8

1 water reduction performance: immediate mortar flow value is "excellent" at 185 or more, ". good" from 175 to less than 185, ". delta" from 170 or more to less than 175, and "x" from less than 170 "

Slump flow persistence ×.:

(immediate mortar flow value) - (mortar flow value after 2 hours) | is "very good" when less than 5, ". good" when 5 or more and less than 10, ". delta" when 10 or more and less than 20, and "x" when 20 or more "

In the mortar flow test, the copolymers obtained in examples 3 to 10 exhibited excellent balance between water-reducing ability and slump flow retention property, while the copolymer obtained in comparative example 6, which contained only the compound D-3 as a long-chain polyalkylene glycol group, exhibited an improvement in water-reducing ability, but the slump flow retention property was significantly lowered. It is known that the water-reducing performance, the slump flow retention property and the concrete viscosity of the same samples vary in the mortar flow test and the concrete test, and the evaluation is carried out by extending the test to the concrete test in order to accurately evaluate the performance obtained from the mortar test results.

Test example 2: concrete test

The concrete ratios used in concrete tests 1 to 4 are shown in the following table.

TABLE 9

Number of the mixture ratio	Proportioning 1	Proportioning-2	Proportioning-3	Proportioning-4
					W/B(％)	20.0	15.0	12.0	30.0
Water (W)	145	150	153	145
					Adhesive material 1	725	1000	1275	484
Fine aggregate 2	712	462	219	805
					Coarse aggregate 3	875	875	875	986

Unit: kg/m³

1 proportion of-1 to 3 silica powder cement (density: 3.08 g/cm)³)

Proportioning-4 ordinary Portland cement (density: 3.15 g/cm)³)

*2: crushed sand (density: 2.64 g/cm)³)

*3: hard macadam (density: 2.65 g/cm)³)

Concrete test 1

Test conditions Water/Binder ratio (W/B) 20%

In this test, the composition 1 in the compositions shown in Table 9 was used.

Watch 10

The addition amounts in the table represent the ratio of the dispersant solids to the binder.

As shown by the results of this test, the copolymers of examples 3 to 5 were excellent in water-reducing property, slump flow persistence, quick setting property and strength, and also excellent in concrete viscosity in the concrete test in which the ratio of water to binder was low (W/B ═ 20%).

Concrete test 2

Test conditions Water/Binder ratio (W/B) 15%

In this test, the composition-2 of the compositions shown in Table 9 was used.

TABLE 11

The addition amounts in the table represent the ratio of the dispersant solids to the binder.

The time for completing the mixing of the mortar is as follows: the time from the start of kneading to completion of mortar formation was visually evaluated.

The results obtained are that the copolymers of examples 4, 6, 8 have high water reducing capacity, excellent slump flow persistence and rapid achievement of strength, maintaining low concrete viscosity, despite in the low water/binder ratio range (W/B ═ 15%). And the time required for forming uniform mortar is short, and the time required for obtaining well-conditioned concrete is short.

Concrete test 3

Test conditions Water/Binder ratio (W/B) 12%

In this test, the composition-3 of the compositions shown in Table 9 was used.

TABLE 12

The addition amounts in the table represent the ratio of the dispersant solids to the binder.

As shown in this test, in the lower range of the water/binder ratio (W/B12%), the amount of dispersant added to the concrete had to be greatly increased, resulting in a very late setting time. As a result, the copolymers of examples 4, 6 and 8 were excellent in water-reducing property, slump flow persistence and quick setting property, and also excellent in concrete viscosity.

Concrete test 4

Test conditions Water/Cement ratio (W/C) 30%

In this test, the composition-4 of the compositions shown in Table 9 was used.

Watch 13

The addition amounts in the table represent the ratio of the dispersant solids to the binder.

If the copolymer of example 4 is used alone in a high water/cement ratio range (W/C ═ 30%), as a result, slump flow persistence is remarkably decreased, and it is suitable as a dispersant for concrete secondary products which face no emphasis on slump flow persistence, and also can give effects of high initial water-reducing property, short setting time and lowering concrete viscosity in combination with a general-purpose dispersant.

Claims (6)

1. A cement dispersant comprising a water-soluble amphoteric copolymer obtained by copolymerizing a monomer mixture containing the following compounds as monomer components and further containing a copolymerizable monomer other than the compounds A to D in a proportion of 30% by weight or less of the total monomer content, or a partially neutralized salt or a completely neutralized salt thereof:

at least one compound A obtained by adding 0 to 8 moles of alkylene oxide having 2 to 4 carbon atoms to 1 equivalent of the amino residue of a polyamidopolyamine obtained by condensing 0.5 to 0.95 mole of an ester of a polyalkylenepolyamine having 1.0 mole of a dibasic acid or a dibasic acid and a lower alcohol having 1 to 4 carbon atoms and 0.05 to 0.70 mole of an ester of acrylic acid or methacrylic acid or an ester of an acrylic acid or methacrylic acid and a lower alcohol having 1 to 4 carbon atoms, and

at least one compound represented by the general formula (1), i.e., compound B:

in the formula, R¹Represents a hydrogen atom or a methyl group, M represents a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group or an alkanolammonium group, and

at least one compound represented by the general formula (2), i.e., compound C:

in the formula, R²Represents a hydrogen atom or a methyl group, R³Represents an alkylene group having 2 to 4 carbon atoms, R⁴Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and m is the number of moles of polyalkylene glycol added and represents an integer of 1 to 35, and

at least one compound represented by the general formula (3), i.e., compound D:

in the formula, R⁵Represents a hydrogen atom or a methyl group, R⁶Represents an alkylene group having 2 to 4 carbon atoms, R⁷Represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is the number of addition mols of polyalkylene glycol and represents an integer of 40 to 100,

the water-soluble amphoteric copolymer is obtained by copolymerizing compounds A to D in a ratio of 5 to 25% by weight, 5 to 30% by weight, 5 to 40% by weight, and 20 to 80% by weight, based on 100% by weight of the total of the compounds A to D.

2. A cement dispersant as claimed in claim 1, wherein in said compound A, when the number of moles of the dibasic acid or the ester of the dibasic acid with a lower alcohol having 1 to 4 carbon atoms is represented by x and the number of moles of the acrylic acid or methacrylic acid or the ester of the acrylic acid or methacrylic acid with a lower alcohol having 1 to 4 carbon atoms is represented by y, the following condition is satisfied, where the number of moles of the compound A is 1.0 mole relative to the polyalkylene polyamine:

0.6＜y/(1-x)＜1.4。

3. an admixture for mortar and concrete, which is a mixture of the cement dispersant of claim 1 or 2 and at least one other additive for mortar and concrete selected from the group consisting of other cement dispersants, defoaming agents and air-entraining agents.

4. A concrete composition characterized by containing the cement dispersant as claimed in claim 1 or 2.

5. A concrete composition comprising the admixture for mortar and concrete according to claim 3.

6. The concrete composition according to claim 4 or 5, which is used for ultra-high performance concrete.