JP6228739B2 - Oxyalkylene group-containing carboxylic acid polymer and dispersant - Google Patents

Description

The present invention relates to an oxyalkylene group-containing carboxylic acid polymer. More specifically, the present invention relates to an oxyalkylene group-containing carboxylic acid polymer suitably used for a dispersant, a cement admixture, a cement composition and the like.

A polymer containing a polyalkylene glycol chain is imparted with properties such as hydrophilicity, hydrophobicity, steric repulsion, etc. by appropriately adjusting the chain length and the constituent alkylene oxide, and cement composition such as cement paste, mortar, concrete, etc. The use of cement admixtures added to materials is being studied. Such a cement admixture is usually used as a water reducing agent (dispersant) or the like, and improves the strength and durability of the cured product by reducing the water content of the cement composition by increasing the fluidity of the cement composition. Used for the purpose of exerting the action. As a water reducing agent, a water reducing agent such as naphthalene was conventionally used, but the polyalkylene glycol chain can act as a dispersing group to disperse cement particles due to its steric repulsion, and therefore contains a polyalkylene glycol chain. The polycarboxylic acid-based water reducing agent has been newly proposed as exhibiting a high water reducing action, and has recently been used as a high-performance AE water reducing agent.

As a conventional polycarboxylic acid polymer containing a polyalkylene glycol chain, for example, a polymer containing a polyalkylene glycol ester of (meth) acrylic acid is generally used, and has a certain effect in dispersibility and water reduction. Demonstrate. In addition, a copolymer component containing a polyalkylene glycol ester of a dicarboxylic acid such as maleic acid instead of a monocarboxylic acid such as (meth) acrylic acid has been studied (for example, see Patent Documents 1 to 3). . Patent Document 1 includes, as an essential component, a copolymer of a dicarboxylic acid monomer obtained by adding 2 to 300 moles of an average addition mole number of an oxyalkylene group having 2 to 3 carbon atoms and a dicarboxylic acid monomer. It is described that the concrete admixture contained exhibits excellent effects on fluidity and fluidity retention. Patent Document 2 describes that a copolymer of itaconic acid and esterified itaconic acid can be obtained by esterifying poly itaconic anhydride and alkoxy polyalkylene glycol. Patent Document 3 describes that a copolymer of a polyalkylene glycol diester of dicarboxylic acid such as itaconic acid and (meth) acrylic acid is excellent in dispersibility and water reduction.

JP-A-9-132445 JP 2011-132383 A Special table 2008-512541 gazette

As described above, carboxylic acid monomers containing a polyalkylene glycol chain and copolymers of carboxylic acid monomers with various structures have been disclosed. It contains a monomer as a main component. Such a copolymer has not yet been able to sufficiently exhibit the extremely high performance (cement dispersibility (water-reducing), slump flow) that has recently been demanded. Cement dispersibility is a very important factor related to workability in the field of handling cement and strength after hardening of cement, and a cement admixture that realizes a cement composition with better performance is required. .

The present invention has been made in view of the above situation, and an oxyalkylene group-containing carboxylic acid polymer excellent in water reduction and retention in a cement composition or the like, and the oxyalkylene group-containing carboxylic acid polymer. It aims at providing the dispersing agent containing.

The present inventors have made various studies on polymers that can be used as cement admixtures with excellent performance such as cement dispersibility (water-reducing properties). As a result, the monomer derived from the carboxylic acid monomer (A) having an oxyalkylene group is used. An oxyalkylene group-containing carboxylic acid polymer mainly composed of a body unit, wherein the monomer (A) is at least one of two COOM groups of a dicarboxylic acid monomer having a specific structure. The inventors have found that an oxyalkylene group-containing carboxylic acid polymer is excellent in water-reducing property and retention when it has a structure in which a polyalkylene glycol having a specific structure is added, and the present invention has been achieved.

That is, the present invention is an oxyalkylene group-containing carboxylic acid polymer mainly comprising a monomer unit derived from a carboxylic acid monomer having an oxyalkylene group (A), wherein the monomer (A) is And having a structure in which a polyalkylene glycol represented by the following general formula (2) is added to at least one of the two COOM groups of the dicarboxylic acid monomer represented by the following general formula (1). Is an oxyalkylene group-containing carboxylic acid polymer.

In the formula, any one of R ¹ , R ² and R ³ represents —COOM or — (CH ₂ ) _m COOM, and —COOM or — (CH ₂ ) _m COOM represents an anhydride with another COOM group. May be formed. m represents an integer of 1 to 2. When any one of R ¹ , R ² , and R ³ is —COOM, any one represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the remaining one has 1 to 1 carbon atoms. Represents 10 alkyl groups. When any one of R ¹ , R ² and R ³ is — (CH ₂ ) _m COOM, the remaining two are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. . M is the same or different and represents a hydrogen atom, a monovalent metal, a divalent metal, a trivalent metal, a quaternary ammonium group, or an organic amine group.

In formula, -R < ⁵ > -O- is the same or different and represents a C2-C18 oxyalkylene group. n represents the average addition mole number of an oxyalkylene group, and represents the number of 1-1000. R ⁴ and R ⁶ are the same or different and have a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms which may have a substituent, or a substituent. An aralkyl group having 7 to 22 carbon atoms which may be used. However, one of R ⁴ and R ⁶ is a hydrogen atom.

The present invention is also a dispersant containing the oxyalkylene group-containing carboxylic acid polymer.
The present invention is described in detail below.
A combination of two or more preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.

<Monomer (A)>
The oxyalkylene group-containing carboxylic acid polymer of the present invention mainly comprises monomer units derived from the carboxylic acid monomer (A) having an oxyalkylene group.
Here, the monomer unit derived from the carboxylic acid monomer (A) having an oxyalkylene group refers to a structure (double bond (C = C) corresponds to a single bond (-C—C—).

Further, the “main body” as used herein refers to a carboxylic acid monomer having an oxyalkylene group (A) when the oxyalkylene group-containing carboxylic acid polymer is composed of two or more monomer units. This means that the derived monomer units occupy most of the total number of monomer units. When “dominating” is expressed in terms of mol% of the monomer unit derived from the carboxylic acid monomer (A) having an oxyalkylene group with respect to 100 mol% of all monomer units, it may exceed 50 mol%. preferable. Thereby, the polycarboxylic acid polymer obtained by copolymerization of a carboxylic acid monomer having a conventional oxyalkylene group and a carboxylic acid monomer can have a different polymer main chain skeleton. . As a result, the polymer adsorption state and dispersion state on the cement surface can be improved. More preferably 60 mol% or more, still more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, most preferably 100 mol%, that is, Only the monomer unit derived from the carboxylic acid monomer (A) having a substantially oxyalkylene group is included.

When the oxyalkylene group-containing carboxylic acid polymer is composed of two or more monomer units, the oxyalkylene group-containing carboxylic acid polymer is a carboxylic acid monomer having an oxyalkylene group (A And other monomer units derived from other monomers.
Examples of the other monomers include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, mesaconic acid, and citraconic acid, and carboxylic anhydrides thereof. Or these salts are mentioned. Among these, acrylic acid, methacrylic acid, or salts thereof are preferable. Two or more of these other monomers may be used in combination.

When the oxyalkylene group-containing carboxylic acid polymer is composed of two or more types of monomer units, the two or more types of monomer units are added in any form such as random addition, block addition, and alternate addition. It may be what you did.

In the oxyalkylene group-containing carboxylic acid polymer of the present invention, the monomer (A) is at least one of the two COOM groups of the dicarboxylic acid monomer represented by the general formula (1). And a structure to which the polyalkylene glycol represented by the general formula (2) is added.
That is, for example, in the general formula (1), R ¹ and R ² are the same or different and are a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ³ is — (CH ₂ ) _m COOM. In this case, the monomer (A) is any one of two COOM groups of the dicarboxylic acid monomer as represented by the following general formulas (3-1) to (3-2). One may have a structure (monoester structure) in which the above polyalkylene glycol is added. For example, as represented by the following general formula (3-3), the dicarboxylic acid monomer It may have a structure (diester structure) in which the polyalkylene glycol is added to both of the two COOM groups of.

In the formula, R ¹ , R ² , m, and M are the same as those in the general formula (1). R ⁵ , R ⁶ and n are the same as those in the general formula (2). R ^5a and ^{R 5b} are the same or different and is the same as ^{R 5} in formula (2). R ^6a and ^{R 6b} are the same or different, is the same as ^{R 6} in formula (2). n _a and _nb are the same or different and are the same as n in the general formula (2).

The oxyalkylene group-containing carboxylic acid polymer of the present invention comprises a monomer unit derived from the monomer (A) having the monoester structure and a monomer unit derived from the monomer (A) having the diester structure. You may have both. Such a form is also one of the preferred forms of the present invention.
The oxyalkylene group-containing carboxylic acid polymer has both a monomer unit derived from the monomer (A) having the monoester structure and a monomer unit derived from the monomer (A) having the diester structure. When it is, the content of the monomer unit derived from the monomer (A) having a monoester structure is 50 mol% with respect to 100 mol% of the monomer units derived from all the monomers (A). Preferably there is. Thereby, sufficient carboxyl groups can be introduced to adsorb the polymer onto the cement surface. As a result, the cement dispersion performance is further improved. More preferably 60 mol% or more, still more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, most preferably 100 mol%, that is, Only the monomer unit derived from the monomer (A) having a monoester structure is included.

When the oxyalkylene group-containing carboxylic acid polymer of the present invention is any one of R ¹ , R ² , and R ^{3 in} the general formula (1) being — (CH ₂ ) _m COOM, — (CH ₂ ) The monomer unit derived from the monomer (A) of the monoester structure (for example, the structure represented by the general formula (3-1)) in which the polyalkylene glycol is added to _m COOM, and the above-mentioned to -COOM It may have both the monomer unit derived from the monomer (A) of the monoester structure (for example, the structure represented by the general formula (3-2)) to which polyalkylene glycol is added. Such a form is also one of the preferred forms of the present invention.

The oxyalkylene group-containing carboxylic acid polymer is a monomer unit derived from a monomer (A) having a monoester structure in which the polyalkylene glycol is added to — (CH ₂ ) _m COOM; And a monomer unit derived from the monomer (A) having a monoester structure to which an alkylene glycol is added, the unit having a monoester structure in which the polyalkylene glycol is added to — (CH ₂ ) _m COOM. The content of the monomer unit derived from the monomer (A) is preferably 50 mol% with respect to 100 mol% of the monomer unit derived from the monomer (A) having a total monoester structure. More preferably 60 mol% or more, still more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, most preferably 100 mol%, that is, It is substantially including only the monomer unit derived from the monomer (A) having a monoester structure in which the polyalkylene glycol is added to — (CH ₂ ) _m COOM.

When the oxyalkylene group-containing carboxylic acid polymer of the present invention has a monomer unit derived from the monomer (A) having a monoester structure in which the polyalkylene glycol is added to — (CH ₂ ) _m COOM, It can be said that it is a preferable embodiment because it is easy to make this structure in production. For example, in the manufacturing method as described later, it is considered that the structure is easily taken in a chemical reaction. In addition, it is preferable that the COOM group is directly bonded to the main chain skeleton of the polymer (a chain portion formed by polymerization of double bonds) because dispersibility to cement or the like is easily exhibited.

From the above, the oxyalkylene group-containing carboxylic acid polymer of the present invention is a homopolymer composed only of monomer units derived from the carboxylic acid monomer (A) having an oxyalkylene group, and is a monoester. A monomer derived from the monomer (A) having a monoester structure containing only the monomer unit derived from the monomer (A) having a structure and having the polyalkylene glycol added to — (CH ₂ ) _m COOM. Most preferably, it contains only monomeric units. Such a form is also one of the preferred forms of the present invention.

The oxyalkylene group-containing carboxylic acid polymer of the present invention has a weight average molecular weight (Mw) in consideration of its handleability and the retention of the cement composition when the polymer is used for cement admixture. Is preferably 1 million or less. More preferably, it is 500,000 or less, more preferably 300,000 or less, still more preferably 200,000 or less, particularly preferably 150,000 or less, particularly more preferably 100,000 or less, and most preferably 50,000 or less. Further, when used for cement admixture, it is preferable that Mw is 1,000 or more from the viewpoint that the performance is better when adsorbed to cement particles to some extent, and the greater the Mw, the greater the adsorptive power. More preferably, it is 5,000 or more, more preferably 10,000 or more, particularly preferably 20,000 or more, and most preferably 30,000 or more.
The number average molecular weight (Mn) is preferably 500,000 or less. More preferably, it is 250,000 or less, More preferably, it is 150,000 or less, Even more preferably, it is 100,000 or less, Especially preferably, it is 75,000 or less, Most preferably, it is 35,000 or less. Moreover, it is preferable that it is 1,000 or more. More preferably, it is 2,500 or more, more preferably 5,000 or more, particularly preferably 10,000 or more, and most preferably 15,000 or more.
The weight average molecular weight and number average molecular weight of the compound can be determined by gel permeation chromatography (GPC) analysis.

<Dicarboxylic acid monomer>
In the oxyalkylene group-containing carboxylic acid polymer of the present invention, the dicarboxylic acid monomer is represented by the following general formula (1).

In the formula, any one of R ¹ , R ² and R ³ represents —COOM or — (CH ₂ ) _m COOM, and —COOM or — (CH ₂ ) _m COOM represents an anhydride with another COOM group. May be formed. m represents an integer of 1 to 2. When any one of R ¹ , R ² , and R ³ is —COOM, any one represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the remaining one has 1 to 1 carbon atoms. Represents 10 alkyl groups. When any one of R ¹ , R ² and R ³ is — (CH ₂ ) _m COOM, the remaining two are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. . M is the same or different and represents a hydrogen atom, a monovalent metal, a divalent metal, a trivalent metal, a quaternary ammonium group, or an organic amine group.

In General Formula (1), any one of R ¹ , R ² , and R ³ represents —COOM or — (CH ₂ ) _m COOM. That is, the dicarboxylic acid monomer is an unsaturated dicarboxylic acid monomer in which —COOM and — (CH ₂ ) _m COOM or two —COOM are bonded to a C═C double bond. Incidentally, -COOM or _{- (CH} 2) m COOM may be formed with other COOM groups and anhydride.

In the general formula (1), when ^one of R ¹ , R ² and R ³ is —COOM, the dicarboxylic acid represented by the following general formulas (4-1) to (4-3) The case where it is a system monomer or these salts is said. The dicarboxylic acid monomers represented by the following general formulas (4-1) to (4-3) or salts thereof form, for example, an anhydride as represented by the following general formula (4-4) You may do it. The following general formula (4-4) represents a dicarboxylic acid monomer represented by the following general formula (4-2) or an anhydride of these salts.

In the formula, R ^{1 to} R ³ and M are the same as those in the general formula (1).

In the general formula ^(1), R ^1, R 2, ^{R 3,} when any one of R ^1, R 2, ^{R 3} is a -COOM, one is a hydrogen atom, or a carbon An alkyl group having 1 to 10 carbon atoms is represented, and the remaining one represents an alkyl group having 1 to 10 carbon atoms. That is, for example, in the general formula (4-1), since R ¹ is —COOM, one of R ^{2 and} R ³ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. The remaining one represents an alkyl group having 1 to 10 carbon atoms.

Specific examples of the alkyl group having 1 to 10 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, n-hexyl group, cyclohexyl group, n -A decyl group etc. are preferable.

In the general formula (1), when any one of R ¹ , R ² and R ³ is — (CH ₂ ) _m COOM, the following general formulas (5-1) to (5-3) are used. The case where it is the dicarboxylic acid type monomer represented or these salts is said. The dicarboxylic acid monomers represented by the following general formulas (5-1) to (5-3) or salts thereof form, for example, an anhydride as represented by the following general formula (5-4) You may do it. The following general formula (5-4) represents a dicarboxylic acid monomer represented by the following general formula (5-3) or an anhydride of these salts.

In the formula, R ^{1 to} R ³ , m, and M are the same as those in the general formula (1).

In the general formula ^{(1), R 1, R} 2, R 3 ^is any one of R ^1, R 2, ^{R 3} _- if it is _(CH 2) m COOM, the remaining two are the same Or, differently, it represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. That is, for example, in the general formula (5-1), since R ¹ is — (CH ₂ ) _m COOM, R ² and R ³ are the same or different, and are a hydrogen atom or a carbon number of 1 to Represents 10 alkyl groups.

Specific examples of the alkyl group having 1 to 10 carbon atoms include, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, n-hexyl group, cyclohexyl group, n -A decyl group etc. are preferable.

Specific examples of the dicarboxylic acid monomers represented by the general formulas (4-1) to (4-3) include dicarboxylic acid monomers such as mesaconic acid and citraconic acid, and carboxylic acids thereof. Anhydrides or their salts (e.g. salts of monovalent metals, divalent metals, trivalent metals, quaternary ammonium or organic amines) are preferred.
Specific examples of the dicarboxylic acid monomer represented by the general formulas (5-1) to (5-3) include dicarboxylic acid monomers such as itaconic acid and glutaric acid, and carboxylic acids thereof. Anhydrides or their salts (e.g. salts of monovalent metals, divalent metals, trivalent metals, quaternary ammonium or organic amines) are preferred.
Among these, from the viewpoint of polymerizability, itaconic acid, glutaric acid, itaconic anhydride or a salt thereof is preferable, and itaconic acid or a salt thereof is particularly preferable.
Two or more of these monomers may be used in combination.

In the general formula (1), examples of the group represented by M include a hydrogen atom; a monovalent metal atom such as an alkali metal atom such as lithium, sodium and potassium; an alkaline earth metal atom such as calcium and magnesium; A trivalent metal atom such as aluminum or iron. Moreover, as an organic amine group, alkanolamine groups, such as an ethanolamine group, a diethanolamine group, and a triethanolamine group, a triethylamine group etc. are mentioned, for example.

<Polyalkylene glycol>
In the oxyalkylene group-containing carboxylic acid polymer of the present invention, the polyalkylene glycol is represented by the following general formula (2).

In formula, -R < ⁵ > -O- is the same or different and represents a C2-C18 oxyalkylene group. n represents the average addition mole number of an oxyalkylene group, and represents the number of 1-1000. R ⁴ and R ⁶ are the same or different and have a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms which may have a substituent, or a substituent. An aralkyl group having 7 to 22 carbon atoms which may be used. However, one of R ⁴ and R ⁶ is a hydrogen atom.

In the said General formula (2), -R < ⁵ > -O- is the same or different and represents a C2-C18 oxyalkylene group.
More preferably, it is an oxyalkylene group having 2 to 8 carbon atoms, such as oxyethylene group, oxypropylene group, oxybutylene group, oxyisobutylene group, oxy-1-butene group, oxy-2-butene group, oxytrimethyl. Examples include an ethylene group, an oxytetramethylene group, an oxytetramethylethylene group, an oxymonobutadiene group, and an oxyoctylene group. In addition, aliphatic epoxy groups such as oxydipentaneethylene group and oxydihexaneethylene group; alicyclic epoxy groups such as oxytrimethylene group, oxytetramethylene group, tetrahydrofuranyl group, tetrahydropyranyl group, and oxyoctylene group; Aromatic epoxide groups such as oxystyrene group and oxy-1,1-diphenylethylene group can also be used.

The oxyalkylene group is preferably appropriately selected according to the use required for the oxyalkylene group-containing carboxylic acid polymer of the present invention. For example, when used for the production of a cement admixture component, From the viewpoint of affinity with cement particles, it is preferable that the main component is a relatively short-chain oxyalkylene group having about 2 to 8 carbon atoms. More preferably, the main component is an oxyalkylene group having 2 to 4 carbon atoms such as an oxyethylene group, an oxypropylene group, and an oxybutylene group, and still more preferably an oxyethylene group.

The “main body” as used herein means that when the polyalkylene glycol chain is composed of two or more oxyalkylene groups, it accounts for the majority of the total number of oxyalkylene groups. When expressing “dominate” in terms of mol% of oxyethylene groups in 100 mol% of all oxyalkylene groups, 50 to 100 mol% is preferable. Thereby, the oxyalkylene group-containing carboxylic acid polymer of the present invention has higher hydrophilicity. More preferably, it is 60 mol% or more, More preferably, it is 70 mol% or more, Especially preferably, it is 80 mol% or more, Most preferably, it is 90 mol% or more.

In the case where the oxyalkylene group-containing carboxylic acid polymer is composed of two or more oxyalkylene groups, two or more oxyalkylene groups are added in any form such as random addition, block addition, and alternate addition. It may be.

When the oxyalkylene group-containing carboxylic acid polymer includes an oxyalkylene group having 3 or more carbon atoms, the oxyalkylene group-containing carboxylic acid polymer of the present invention may be imparted with a certain degree of hydrophobicity. Therefore, when the polymer is used as a cement admixture, the cement particles are given a slight structure (network), and the viscosity and stiffness of the cement composition can be reduced. On the other hand, if the oxyalkylene group having 3 or more carbon atoms is introduced too much, the hydrophobicity of the polymer becomes too high, so that the performance of dispersing cement particles may not be sufficient. For this reason, it is preferable that content of a C3 or more oxyalkylene group with respect to 100 mass% of all oxyalkylene groups is 30 mass% or less. More preferably, it is 25 mass% or less, More preferably, it is 20 mass% or less, Most preferably, it is 5 mass% or less.
Depending on the application required for the polymer, an embodiment that does not contain an oxyalkylene group having 3 or more carbon atoms may be preferable.

In the said General formula (2), n represents the average addition mole number (average repeating number of an oxyalkylene group) of an oxyalkylene group, and represents the number of 1-1000.
When the average added mole number of the oxyalkylene group is 1 or more, the polymer can sufficiently exhibit the performance based on the polyalkylene glycol.
In addition, when the average number of added moles of the oxyalkylene group exceeds 1000, the viscosity of the raw material compound used for producing the polymer is increased, and the reactivity is not sufficient. There is a possibility that it may not be suitable.
The lower limit of the average number of added moles is more preferably 10, still more preferably 20, even more preferably 50, particularly preferably 75, particularly more preferably 80, and most preferably 100. The upper limit is more preferably 800, still more preferably 700, still more preferably 600, particularly preferably 500, particularly more preferably 300, and most preferably 200.

In the general formula (2), R ⁴ and R ⁶ are the same or different and are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 14 carbon atoms which may have a substituent, Or the C7-22 aralkyl group which may have a substituent is represented. However, one of R ⁴ and R ⁶ is a hydrogen atom.

Specific examples of the alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, n-hexyl group, cyclohexyl group, and n-decyl. Group and the like. Specific examples of the aryl group having 6 to 14 carbon atoms which may have a substituent include a phenyl group, a tolyl group, a p-hydroxyphenyl group, and a naphthyl group. Specific examples of the aralkyl group having 7 to 22 carbon atoms which may have a substituent include 1- (p-hydroxyphenyl) ethyl group, 2- (p-hydroxyphenyl) ethyl group, and benzyl group. It is done.

<Method for producing oxyalkylene group-containing carboxylic acid polymer>
Although it does not specifically limit as a manufacturing method of the oxyalkylene group containing carboxylic acid type polymer in this invention, For example, it can manufacture by performing the following processes.

(I-1) Esterification reaction step to carboxylic acid First, the COOM group possessed by the carboxylic acid is reacted with the hydroxyl group at the terminal of the polyalkylene glycol to produce an ester bond to obtain a carboxylic acid ester.

A catalyst may be used in the esterification reaction of (i-1) to a carboxylic acid. As the catalyst, for example, sulfonic acid compounds such as methanesulfonic acid and toluenesulfonic acid are preferable. Further, from the viewpoint of preventing the polymerization of carboxylic acid, phenothiazine, N oxyl compound, phenol compound, manganese salt such as manganese acetate, dialkyldithiocarbamate copper salt such as copper dibutylthiocarbamate, nitroso compound, and amine compound are preferable, Since it has high thermal stability, it can be produced without using these catalysts. When these catalysts are used, the content of the catalyst is preferably 200 ppm or less with respect to the total mass of the carboxylic acid and the polyalkylene glycol. More preferably, it is 100 ppm or less, More preferably, it is 50 ppm or less.

The esterification reaction of (i-1) to a carboxylic acid can be performed in the presence of a solvent such as benzene, toluene, xylene, cyclohexane and the like. The concentration of the reaction substrate in the solvent (the total amount of carboxylic acid and polyalkylene glycol) is preferably 50 to 98% by mass, more preferably 70 to 95% by mass, from the viewpoint of suitably proceeding the reaction.

(I-2) Step of esterification reaction to carboxylic anhydride In addition to the esterification reaction to carboxylic acid of (i-1) above, the terminal hydroxyl group of polyalkylene glycol is reacted with the corresponding carboxylic acid anhydride. Carboxylic acid ester can also be obtained.

A catalyst may be used in the esterification reaction of (i-2) to the carboxylic acid anhydride. As the catalyst, for example, sulfonic acid compounds such as methanesulfonic acid and toluenesulfonic acid, and amine compounds such as pyridine and N, N-dimethylaminopyridine are preferable. Further, from the viewpoint of preventing polymerization of carboxylic acid anhydride, phenothiazine, N oxyl compound, phenol compound, manganese salt such as manganese acetate, copper dialkyldithiocarbamate such as copper dibutylthiocarbamate, nitroso compound, and amine compound are preferable. However, since it has high thermal stability, it can be produced without using these catalysts. When these catalysts are used, the content of the catalyst is preferably 200 ppm or less with respect to the total mass of the carboxylic acid anhydride and the polyalkylene glycol. More preferably, it is 100 ppm or less, More preferably, it is 50 ppm or less.

The esterification reaction of (i-2) to a carboxylic acid anhydride can be performed without a solvent, but in the presence of a solvent such as benzene, toluene, xylene, cyclohexane, dichloromethane, chloroform, diethyl ether, tetrahydrofuran, and the like. It can also be done. The concentration of the reaction substrate in the solvent (the total amount of carboxylic acid anhydride and polyalkylene glycol) is preferably 50 to 98% by mass, more preferably 70 to 95% by mass, from the viewpoint of suitably proceeding the reaction. preferable.

In the esterification reaction of (i-1) and (i-2) above, the reaction temperature is preferably 50 to 220 ° C. Thereby, esterification can be performed in a high yield in a short time. If the reaction temperature is less than 50 ° C., the reaction takes a long time. On the other hand, when the reaction time exceeds 220 ° C., the progress of the reaction is not accelerated any more, which is disadvantageous. As reaction temperature, More preferably, it is 60-200 degreeC, More preferably, it is 70-180 degreeC, Most preferably, it is 80-150 degreeC.

(Ii) Polymerization step Next, the carboxylic acid ester is polymerized using a radical polymerization initiator.

The polymerization reaction can be performed by a method such as solution polymerization or bulk polymerization. The solution polymerization can be performed batchwise, continuously, or a combination thereof. Examples of the solvent used in this case include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; benzene, toluene, Aromatic or aliphatic hydrocarbons such as 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. Among them, for example, when used in an application that is often used as an aqueous solution such as a cement admixture, polymerization is preferably performed by an aqueous solution polymerization method.

Among the above solution polymerizations, in aqueous solution polymerization, it is preferable to use a water-soluble radical polymerization initiator because it is not necessary to remove insoluble components after polymerization. For example, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; hydrogen peroxide; azoamidine compounds such as 2,2′-azobis-2-methylpropionamidine hydrochloride, 2,2′-azobis-2- Cyclic azoamidine compounds such as (2-imidazolin-2-yl) propane hydrochloride, azonitrile compounds such as 2-carbamoylazoisobutyronitrile, 2,4′-azobis {2-methyl-N- [2- (1- Water-soluble azo initiators such as azoamide compounds such as (hydroxybutyl)] propionamide}, macroazo compounds such as esters of 4,4′-azobis (4-cyanovaleric acid) and (alkoxy) polyethylene glycol, These 1 type (s) or 2 or more types can be used. Of these, azoamidine compound-based initiators are preferred.

At this time, alkali metal sulfite such as sodium hydrogen sulfite, metabisulfite, sodium hypophosphite, Fe (II) salt such as molle salt, hydroxymethanesulfinate sodium dihydrate, hydroxylamine hydrochloride, thiourea , L-ascorbic acid (salt), erythorbic acid (salt) and other accelerators (reducing agents) can be used in combination. For example, a combination of hydrogen peroxide and an organic reducing agent is possible. Examples of the organic reducing agent include L-ascorbic acid (salt), L-ascorbic acid ester, erythorbic acid (salt), erythorbic acid ester, and the like. It can be used suitably. These radical polymerization initiators and accelerators (reducing agents) may be used alone or in combination of two or more.
The amount of the accelerator (reducing agent) used is not particularly limited. For example, when the total amount of the polymerization initiator used in combination is 100 mol%, it is preferably 10 mol% or more, more preferably 20 mol%. It is at least mol%, more preferably at least 50 mol%, preferably at most 1000 mol%, more preferably at most 500 mol%, still more preferably at most 400 mol%.

In solution polymerization and bulk polymerization using lower alcohols, aromatic or aliphatic hydrocarbons, esters or ketones as solvents, radical polymerization initiators such as benzoyl peroxide, lauroyl peroxide, sodium peroxide, etc. Peroxides such as t-butyl hydroperoxide and cumene hydroperoxide; azonitrile compounds such as azobisisobutyronitrile, 2,4′-azobis {2-methyl-N- [2- (1- 1 or 2 of azo initiators such as azoamide compounds such as hydroxybutyl)] propionamide}, macroazo compounds such as esters of 4,4′-azobis (4-cyanovaleric acid) and (alkoxy) polyethylene glycol More than seeds can be used. Among these, an azo initiator is suitable as will be described later. In this case, an accelerator such as an amine compound can be used in combination.
Furthermore, when using a mixed solvent of water and a lower alcohol, it can be appropriately selected from the above-mentioned various radical polymerization initiators or a combination of the above radical polymerization initiator and accelerator.

The amount of the radical polymerization initiator used may be appropriately set according to the form and amount of the polyalkylene glycol and dicarboxylic acid monomer component, but the dicarboxylic acid monomer used for polymerization by the radical polymerization initiator. If the amount is too small relative to the component, the radical concentration may be too low and the polymerization reaction may be slowed. On the other hand, if the amount is too large, the radical concentration may be too high, making it difficult to adjust the molecular weight. Therefore, the amount of the radical polymerization initiator used is preferably 0.001 mol% or more, more preferably 0.01 mol% or more, and still more preferably 0 with respect to 100 mol% of the total amount of the dicarboxylic acid monomer components. 0.1 mol% or more, particularly preferably 0.2 mol% or more, particularly preferably 1 mol% or more, most preferably 5 mol% or more, and preferably 50 mol% or less, more preferably 20 mol%. Hereinafter, it is more preferably 10 mol% or less, still more preferably 5 mol% or less, particularly preferably 2 mol% or less, and most preferably 1 mol% or less.

In the polymerization reaction, a chain transfer agent may be used in combination. Examples of chain transfer agents that can be used include thiol chain transfer agents such as mercaptoethanol, thioglycerol, thioglycolic acid, 3-mercaptopropionic acid, thiomalic acid, and 2-mercaptoethanesulfonic acid; secondary such as isopropyl alcohol Alcohol; phosphorous acid, hypophosphorous acid or a salt thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionite, metabisulfite or a salt thereof (sodium sulfite, And hydrophilic chain transfer agents such as lower oxides such as sodium bisulfite, sodium dithionite, and sodium metabisulfite) or salts thereof.

A hydrophobic chain transfer agent can also be used as the chain transfer agent. Examples of the hydrophobic chain transfer agent include 3 carbon atoms such as butanethiol, octanethiol, decanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, cyclohexyl mercaptan, thiophenol, octyl thioglycolate, and octyl 3-mercaptopropionate. A thiol chain transfer agent having the above hydrocarbon group is preferably used.

When the chain transfer agent is used, the amount used may be set as appropriate, but it is preferably 0.1 mol% or more, more preferably 0.8 mol% relative to 100 mol% of the total amount of the dicarboxylic acid monomer components. It is 25 mol% or more, more preferably 0.5 mol% or more, preferably 20 mol% or less, more preferably 15 mol% or less, still more preferably 10 mol% or less.

In the above polymerization reaction, the polymerization conditions such as the polymerization temperature are appropriately determined depending on the polymerization method used, the solvent, the polymerization initiator, and the chain transfer agent, but the polymerization temperature is preferably 0 ° C. or higher, It is preferable that it is 150 degrees C or less. More preferably, it is 30 degreeC or more, More preferably, it is 50 degreeC or more. More preferably, it is 120 degrees C or less, More preferably, it is 100 degrees C or less.

In the above polymerization reaction, in order to obtain a polymer having a predetermined molecular weight with good reproducibility, it is preferable to allow the polymerization reaction to proceed stably. Therefore, in solution polymerization, the dissolved oxygen concentration of the solvent to be used at 25 ° C. is set to a range of 5 ppm or less (preferably 0.01 to 4 ppm, more preferably 0.01 to 2 ppm, still more preferably 0.01 to 1 ppm). It is preferable to do. In addition, when nitrogen substitution etc. are performed after adding carboxylic acid ester to a solvent, it is appropriate to make the dissolved oxygen concentration of the system which also contains carboxylic acid ester in the said range.

The dissolved oxygen concentration of the solvent may be adjusted in a polymerization reaction tank, or a dissolved oxygen amount may be adjusted in advance. Examples of the method for driving off oxygen in the solvent include the following methods (1) to (5).
(1) After pressure-filling an inert gas such as nitrogen in a sealed container containing a solvent, the partial pressure of oxygen in the solvent is lowered by lowering the pressure in the sealed container. In that case, you may reduce the pressure in a sealed container under nitrogen stream.
(2) The liquid phase portion is vigorously stirred for a long time while the gas phase portion in the container containing the solvent is replaced with an inert gas such as nitrogen.
(3) An inert gas such as nitrogen is bubbled in the solvent in the container for a long time.
(4) The solvent is once boiled and then cooled in an inert gas atmosphere such as nitrogen.
(5) A static mixer (static mixer) is installed in the middle of the pipe, and an inert gas such as nitrogen is mixed in the pipe for transferring the solvent to the polymerization reaction tank.

The polymer obtained by the above polymerization reaction is easy to handle by adjusting to a pH range of weak acid or higher (more preferably pH 4 or higher, more preferably pH 5 or higher, particularly preferably pH 6 or higher) in an aqueous solution state. can do.
On the other hand, when the polymerization reaction is carried out at a pH of 7 or more, the polymerization rate is lowered, and at the same time, the copolymerizability is not sufficient. For example, when used for cement admixture, there is a possibility that the dispersion performance cannot be sufficiently exhibited. is there. Therefore, in the polymerization reaction, it is suitable to perform the polymerization reaction in a pH range from acidic to neutral (preferably less than pH 6, more preferably less than pH 5.5, and still more preferably less than pH 5). Examples of preferable polymerization initiators that change the polymerization system from acidic to neutral include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, and azoamidine compounds such as azobis-2-methylpropionamidine hydrochloride. It is preferable to use a water-soluble azo initiator such as hydrogen peroxide, a combination of hydrogen peroxide and an organic reducing agent, or the like.

In addition to oxyalkylene group-containing carboxylic acid polymers, reaction products obtained by the above polymerization reaction may contain various polymers as by-products, unreacted raw materials, and impurities contained in the raw materials. If necessary, it may be subjected to a process of isolating individual polymers, but it is usually used for various purposes without isolating individual polymers from the viewpoint of work efficiency and production cost. May be.

The oxyalkylene group-containing carboxylic acid polymer of the present invention can be suitably used for various applications such as an adhesive, a sealing agent, a component for imparting flexibility to various polymers, and a detergent builder. In a composition containing inorganic fine particles such as gypsum and gypsum, it can also be suitably used as a dispersant for dispersing inorganic fine particles.
The dispersant containing the oxyalkylene group-containing carboxylic acid polymer of the present invention is also one aspect of the present invention.
Among them, the oxyalkylene group-containing carboxylic acid-based polymer of the present invention can exhibit extremely high cement dispersion performance as described above, and thus is preferably used for cement admixture. Thus, the cement admixture containing the oxyalkylene group-containing carboxylic acid polymer is also one aspect of the present invention.
The cement admixture can be used in addition to a cement composition such as cement paste, mortar, concrete, etc., and such a cement composition containing the cement admixture is also one aspect of the present invention.

As the above-mentioned cement composition, those containing cement, water, fine aggregate, coarse aggregate and the like are suitable. As the cement, Portland cement (ordinary, early strength, very early strength, moderate heat, sulfate resistance, Or each low alkali type); various mixed cements (blast furnace cement, silica cement, fly ash cement); white Portland cement; alumina cement; super fast cement (1 clinker fast cement, 2 clinker fast cement, magnesium phosphate cement ); Grout cement; oil well cement; low exothermic cement (low exothermic blast furnace cement, fly ash mixed low exothermic blast furnace cement, high content of belite); ultra high strength cement; cement-based solidified material; ecocement (city waste) Cement produced from one or more of incineration ash and sewage sludge incineration ash G) other such, these blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, and a film obtained by adding a fine powder and gypsum limestone powder.
As the above aggregate, in addition to gravel, crushed stone, granulated slag, recycled aggregate, etc., siliceous, clay, zircon, high alumina, silicon carbide, graphite, chrome, chromic, magnesia, etc. Refractory aggregate and the like.

Examples of the unit water amount per 1 m ³ of the cement composition, the cement use amount, and the water / cement ratio (mass ratio) include, for example, a unit water amount of 100 to 185 kg / m ³ , a use cement amount of 200 to 800 kg / m ³ , and a water / cement ratio. The cement ratio (mass ratio) is preferably 0.1 to 0.7, and more preferably, the unit water amount is 120 to 175 kg / m ³ , the cement amount used is 250 to 800 kg / m ³ , and the water / cement ratio ( (Mass ratio) = 0.2 to 0.65. Thus, the cement admixture containing the oxyalkylene group-containing carboxylic acid polymer of the present invention can be used in a wide range from poor blending to rich blending, and has a high water reduction rate range, that is, water / cement. The ratio (mass ratio) = 0.15 to 0.5 (preferably 0.15 to 0.4) can be used even in a low water / cement ratio region, and the unit cement amount is large and the water / cement ratio is high. It is effective for both small high-strength concrete and poor blended concrete with a unit cement amount of 300 kg / m ³ or less.

As the cement admixture of the present invention, the fluidity, retention and workability can be exhibited with high performance in a balanced manner even in a high water reduction rate region, and since it has excellent workability, ready-mixed concrete, concrete secondary products ( It can be used effectively for precast concrete), centrifugal concrete, vibration compaction concrete, steam-cured concrete, shotcrete, etc., and medium fluidity concrete (slump value is 22-25cm) Mortar and concrete that require high fluidity, such as concrete with high fluidity (concrete with a slump value of 25 cm or more and a slump flow value of 50 to 70 cm), self-filling concrete, self-leveling material, etc. Also effective.

When the above cement admixture is used in a cement composition, the blending ratio is such that the oxyalkylene group-containing carboxylic acid polymer, which is an essential component of the present invention, is 100% by mass in terms of solid content. On the other hand, it is preferably set to be 0.01 to 10% by mass. If it is less than 0.01% by mass, the performance may not be sufficient. On the other hand, if it exceeds 10% by mass, the effect will substantially reach its peak, which may be disadvantageous in terms of economy. More preferably, it is 0.02-8 mass%, More preferably, it is 0.05-6 mass%.

The cement admixture can also be used in combination with other known cement additives.
As another cement additive, 1 type (s) or 2 or more types, such as a cement additive (material) as shown below, can be used, for example. Among these, it is particularly preferable to use an oxyalkylene antifoaming agent or an AE agent in combination.
The addition ratio of the cement additive is preferably 0.0001 to 10 parts by mass with respect to 100 parts by mass of the solid content of the oxyalkylene group-containing carboxylic acid polymer.

(1) Water-soluble polymer substances: polyacrylic acid (sodium), polymethacrylic acid (sodium), polymaleic acid (sodium), unsaturated carboxylic acid polymer such as sodium salt of acrylic acid / maleic acid copolymer; polyethylene Polymers of polyoxyethylene or polyoxypropylene such as glycol and polypropylene glycol or copolymers thereof; Nonionic cellulose ethers such as methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, carboxyethylcellulose, hydroxypropylcellulose, etc. Yeast glucan, xanthan gum, β-1,3 glucans (both linear and branched), for example, curdlan, paramylon, pachyman, Polysaccharides produced by microbial fermentation such as reloglucan, laminaran, etc.); polyacrylamide; polyvinyl alcohol; starch; starch phosphate ester; sodium alginate; gelatin; Grade compounds and the like.

(2) Polymer emulsion.
(3) retarder: oxycarboxylic acid such as gluconic acid, malic acid or citric acid, these sodium, potassium, calcium, magnesium, ammonium, triethanolamine or organic salts such as organic salts or salts thereof; glucose, fructose, Galactose, saccharose; sugar alcohols such as sorbitol; magnesium silicofluoride; phosphoric acid and its salts or borate esters; aminocarboxylic acid and its salts; alkali-soluble protein; humic acid; tannic acid; phenol; A monohydric alcohol; aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid) or an alkali metal salt thereof, alkaline earth gold Phosphonic acid or derivatives thereof such as salts.

(4) Early strengthening agent / accelerator: soluble calcium salt such as calcium chloride, calcium nitrite, calcium nitrate, calcium bromide, calcium iodide; alkanolamine; alumina cement; calcium aluminate silicate.
(5) Mineral oil-based antifoaming agent: cocoon oil, liquid paraffin, etc.
(6) Fat and oil-based antifoaming agents: animal and vegetable oils, sesame oil, castor oil, alkylene oxide adducts thereof and the like.
(7) Fatty acid-based antifoaming agent: oleic acid, stearic acid, and these alkylene oxide adducts.
(8) Fatty acid ester antifoaming agent: glycerin monoricinoleate, alkenyl succinic acid derivative, sorbitol monolaurate, sorbitol trioleate, natural wax and the like.

(9) Oxyalkylene antifoaming agents: polyoxyalkylenes such as (poly) oxyethylene (poly) oxypropylene adducts; diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene (Poly) oxyalkyl ethers such as 2-ethylhexyl ether and higher alcohols having 12 to 14 carbon atoms such as oxyethyleneoxypropylene adducts; (poly) oxy such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether Alkylene (alkyl) aryl ethers; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, 3-methyl-1 -Bu Acetylene ethers obtained by addition polymerization of alkylene oxide to acetylene alcohol such as n-3-ol; (poly) oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, ethylene glycol distearate; polyoxyethylene (Poly) oxyalkylene sorbitan fatty acid esters such as sorbitan monolaurate and polyoxyethylene sorbitan trioleate; (poly) oxyalkylene alkyl such as sodium polyoxypropylene methyl ether sulfate and sodium polyoxyethylene dodecylphenol ether sulfate ( Aryl) ether sulfate esters; (poly) oxyethylene stearyl phosphates, etc. Polyoxyalkylene alkyl phosphoric acid esters; polyoxyethylene such as polyoxyethylene lauryl amine (poly) oxyalkylene alkyl amines; polyoxyalkylene amide.

(10) Alcohol-based antifoaming agent: octyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols and the like.
(11) Amide antifoaming agent: acrylate polyamine and the like.
(12) Phosphate ester antifoaming agent: tributyl phosphate, sodium octyl phosphate, etc.
(13) Metal soap type antifoaming agent: aluminum stearate, calcium oleate, etc.
(14) Silicone antifoaming agent: dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil and the like.
(15) AE agent: resin soap, saturated or unsaturated fatty acid, sodium hydroxystearate, lauryl sulfate, ABS (alkyl benzene sulfonic acid), LAS (linear alkyl benzene sulfonic acid), alkane sulfonate, polyoxyethylene alkyl (phenyl) ether , Polyoxyethylene alkyl (phenyl) ether sulfate or a salt thereof, polyoxyethylene alkyl (phenyl) ether phosphate or a salt thereof, protein material, alkenyl sulfosuccinic acid, α-olefin sulfonate, and the like.

(16) Other surfactants: aliphatic monohydric alcohols having 6 to 30 carbon atoms in the molecule such as octadecyl alcohol and stearyl alcohol, and those having 6 to 30 carbon atoms in the molecule such as abiethyl alcohol Intramolecular such as alicyclic monohydric alcohol, dodecyl mercaptan, etc. Intramolecular such as monovalent mercaptan having 6-30 carbon atoms in the molecule, such as nonylphenol, alkylphenol having 6-30 carbon atoms in the molecule, dodecylamine, etc. 10 mol or more of an alkylene oxide such as ethylene oxide or propylene oxide was added to a carboxylic acid having 6 to 30 carbon atoms in the molecule such as an amine having 6 to 30 carbon atoms, lauric acid or stearic acid. Polyalkylene oxide derivatives; having an alkyl group or alkoxyl group as a substituent Alkyl diphenyl ether sulfonates in which two phenyl groups having a sulfone group are ether-bonded; various anionic surfactants; various cationic surfactants such as alkylamine acetate and alkyltrimethylammonium chloride; various nonions Surfactants; various amphoteric surfactants.
(17) Waterproofing agent: fatty acid (salt), fatty acid ester, oil and fat, silicon, paraffin, asphalt, wax and the like.
(18) Rust preventive: nitrite, phosphate, zinc oxide and the like.
(19) Crack reducing agent: polyoxyalkyl ethers; alkanediols such as 2-methyl-2,4-pentanediol.
(20) Expansion material: Ettlingite, coal, etc.

Other cement additives (materials) include, for example, cement wetting agents, thickeners, separation reducing agents, flocculants, drying shrinkage reducing agents, strength enhancing agents, self-leveling agents, rust preventives, colorants, antifungal agents , Blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, gypsum and the like.

Since the oxyalkylene group-containing carboxylic acid polymer of the present invention has the above-described configuration, it is excellent in water reduction and retention in cement compositions and the like. Such an oxyalkylene group-containing carboxylic acid polymer can be suitably used as a dispersant, a cement admixture, and a cement composition.

FIG. 1 shows an example of an RI chromatogram obtained by GPC.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by mass” and “%” means “% by mass”.

Various measurements in the examples were performed as follows.
<Measurement of production rate of itaconic acid monoester by LC>
Device: Waters Alliance (2695)
Analysis software: Waters Empower Professional + GPC option column: Waters Atlantis dC18 guard column + column (particle size 5 μm, inner diameter 4.6 mm × 250 mm × 2)
Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: A mixture of acetonitrile / 100 mM acetate ion exchange aqueous solution = 40/60 (mass%) adjusted to pH 4.0 by adding 30% NaOH aqueous solution Flow rate: 1.0 mL / min Column temperature: 40 ° C.
Sample solution injection amount: 100 μL (eluent solution having a sample concentration of 1 to 2% by mass)

<Measurement of polymer by GPC>
The weight average molecular weight, number average molecular weight and peak top molecular weight of the polymer were measured under the following conditions.
Device: Waters Alliance (2695)
Analysis software: Waters, Empor professional + GPC option column: Tosoh Co., Ltd., TSKguardcolumns SWXL + TSKgel G4000SWXL + G3000SWXL + G2000SWXL
Detector: differential refractometer (RI) detector (Waters 2414), multi-wavelength visible ultraviolet (PDA) detector (Waters 2996)
Eluent: A solution prepared by dissolving 115.6 g of sodium acetate trihydrate in a mixed solvent of 10999 g of water and 6001 g of acetonitrile, and further adjusting the pH to 6.0 with acetic acid. Standard material for preparing a calibration curve: polyethylene glycol (peak top molecular weight (Mp ) 272500, 219300, 107000, 50000, 24000, 12600, 7100, 4250, 1470)
Calibration curve: Flow rate prepared by cubic equation based on Mp value of polyethylene glycol and elution time: 1 mL / min Column temperature: 40 ° C
Measurement time: 45 minutes Sample solution injection amount: 100 μL (eluent solution having a sample concentration of 0.5 mass%)

(GPC analysis conditions)
In the obtained RI chromatogram, the portions that were flat and stable in the baseline immediately before and after elution of the polymer were connected by straight lines, and the polymer was detected and analyzed. FIG. 1 shows an example of the obtained RI chromatogram. As shown in FIG. 1, when the peak of a monomer or an impurity derived from the monomer is partially overlapped with the polymer peak and measured, the polymer part (shown in FIG. S1) and the monomer part (S2 shown in FIG. 1) were separated, and the molecular weight and molecular weight distribution of only the polymer part were measured. When the polymer part and the other part completely overlapped and could not be separated, the calculation was made collectively.
Further, as a measure of the yield of the polymer, the “polymer pure content” was calculated as follows from the ratio of the peak area by the RI detector.
Polymer purity = (Polymer peak area: S1) / (Polymer peak area: S1 + Peak area of monomer or impurity: S2)

<Production Example 1: Production of Itaconic Acid Ester (1)>
Dimroth condenser, Teflon (registered trademark) stirrer blade, stirrer with stir seal, and glass reaction vessel equipped with a temperature sensor, itaconic anhydride (Mandai Chemical Co., Ltd., 261 g) and ethylene oxide on average Methoxypolyethylene glycol added with 10 addition moles (manufactured by Nippon Shokubai Co., Ltd., 1000 g) and phenothiazine (manufactured by Wako Pure Chemical Industries, Ltd., 0.01 g) were charged and stirred at 250 rpm. After the reaction solution became uniform, methanesulfonic acid (Wako Pure Chemical Industries, 45 g) was added and heated to 90 ° C. After reacting at 90 ° C. for 1 hour, it was cooled to room temperature to obtain an itaconic acid ester (1). As a result of LC analysis, the production rate of itaconic acid monoester was 89.77%, and the production rate of itaconic acid diester was 10.23%.

<Production Example 2: Production of Itaconic Acid Ester (2)>
Dimroth condenser, Teflon (registered trademark) stirrer blade, stirrer with stir seal, glass reaction vessel equipped with temperature sensor, itaconic anhydride (Iwata Chemical Co., Ltd., 443 g) and ethylene oxide on average Methoxypolyethylene glycol added with 6 addition moles (manufactured by Nippon Shokubai Co., Ltd., 1000 g) and phenothiazine (manufactured by Wako Pure Chemical Industries, Ltd., 0.01 g) were charged and stirred at 250 rpm. After the reaction solution became uniform, methanesulfonic acid (manufactured by Wako Pure Chemical Industries, 43 g) was added and heated to 90 ° C. After reacting at 90 ° C. for 1 hour, it was cooled to room temperature to obtain an itaconic acid ester (2).
As a result of LC analysis, the production rate of itaconic acid monoester was 89.38%, and the production rate of itaconic acid diester was 10.62%.

<Example 1: Production of polymer (1)>
As an initiator solution, a solution was prepared in which ion-exchanged water was added to ammonium persulfate (manufactured by Wako Pure Chemical Industries, 78 g) to make a total of 278 g.
Dimroth condenser, Teflon (registered trademark) stirrer blade and stirrer with stir seal, 1000 g of itaconic acid ester (1) obtained in Production Example 1 in a glass reaction vessel equipped with a temperature sensor, ion-exchanged water 466 .67 g was charged and heated to 70 ° C. while stirring at 250 rpm and introducing nitrogen at 200 mL / min.
Subsequently, the initiator solution was dropped into the reaction vessel over 1 hour. After completion of the dropwise addition, the polymerization reaction was completed by maintaining at 70 ° C. for 2 hours, and then cooled to room temperature to obtain an aqueous solution of the polymer (1).
As a result of GPC analysis, the polymer was Mw = 8200, Mp = 5300, and Mn = 4300. The pure polymer content was 96.57%.

<Example 2: Production of polymer (2)>
An aqueous solution of the polymer (2) was obtained in the same manner as in Example 1 except that the polymerization reaction was performed at 60 ° C.
As a result of GPC analysis, the polymer was Mw = 11800, Mp = 8100, and Mn = 6800. The pure polymer content was 85.75%.

<Example 3: Production of polymer (3)>
An aqueous solution of polymer (3) was obtained in the same manner as in Example 1 except that the polymerization reaction was performed at 55 ° C.
As a result of GPC analysis, the polymer was Mw = 24200, Mp = 23100, and Mn = 6800. The pure polymer content was 96.57%.

<Example 4: Production of polymer (4)>
As an initiator solution, a solution was prepared by adding ion-exchanged water to ammonium persulfate (manufactured by Wako Pure Chemical Industries, 58 g) to a total of 258 g.
Dimroth condenser, Teflon (registered trademark) stirrer blade, stirrer with stirrer seal, 1000 g of itaconic acid ester (2) obtained in Production Example 2 in a glass reaction vessel equipped with a temperature sensor, ion exchanged water 466 .67 g was charged and heated to 70 ° C. while stirring at 250 rpm and introducing nitrogen at 200 mL / min.
Subsequently, the initiator solution was dropped into the reaction vessel over 1 hour. After completion of the dropwise addition, the polymerization reaction was completed by maintaining at 70 ° C. for 2 hours, and then cooled to room temperature to obtain an aqueous solution of the polymer (4).
As a result of GPC analysis, the polymer was Mw = 10800, Mp = 5800, and Mn = 4300. Further, the pure polymer content was 100%.

<Comparative Examples 1-2: Production of Comparative Polymer>
As a monomer solution, ions of methoxypolyethylene glycol ester compound with an average addition mole number of 9 added by ethylene oxide (manufactured by Shin-Nakamura Chemical Co., Ltd., 1000 g), methacrylic acid (797 g), 30% sodium hydroxide aqueous solution (62 g) Exchange water was added to make a total of 1859 g.
As an initiator solution, a solution was prepared by adding ion-exchanged water to ammonium persulfate (Wako Pure Chemical Industries, 20 g) to make a total of 200 g.
Dimroth condenser, Teflon (registered trademark) stirring blade and stirrer with stirring seal, nitrogen introduction tube, and a glass reaction vessel equipped with a temperature sensor were charged with 560 g of ion-exchanged water. While introducing at 200 mL / min, the mixture was heated to 80 ° C.
Subsequently, the monomer solution was dropped into the reaction vessel over 4 hours and the initiator solution over 5 hours. After completion of the dropwise addition, the temperature was kept at 80 ° C. for 1 hour to complete the polymerization reaction, followed by cooling to room temperature to obtain an aqueous solution of a comparative polymer.
As a result of GPC analysis, the polymer was Mw = 6500, Mp = 4900, and Mn = 4300. The pure polymer content was 95.08%.

<Mortar test>
Using the polymers (1) to (4) produced in Examples 1 to 4 and Comparative Examples 1 and 2 and the comparative polymer as a cement admixture, the slump flow value of the mortar was measured as follows. .
In Comparative Examples 1 and 2, both use a comparative polymer. In Comparative Example 1, the blending amount of the polymer is 0.1% by mass, and in Comparative Example 2, the blending amount of the polymer is 0.12% by mass. did.

(1) Material cement: Ordinary Portland cement (manufactured by Taiheiyo Cement)
Sand: ISO standard sand (2) Mortar content (g)
Water = 264
Cement = 587
Sand = 1350
(3) Test method MA404 (manufactured by BASF Japan) was used as an antifoaming agent. The antifoaming agent was previously dissolved in water to be blended in the mortar and blended. Table 1 shows the blending amounts of the polymer and the antifoaming agent with respect to 100% by mass of the cement.
Using a mechanical kneader described in JIS R5201, the test was conducted according to the mortar flow test method of the same standard. However, the flow value was measured only by raising the cone without performing the drop motion in the mortar flow test. Table 1 shows the results of measuring the flow values immediately after kneading and 30 minutes after water injection.

From comparison between Examples 1 to 4 and Comparative Example 1, the polymers (1) to (4) mainly composed of monomer units derived from the specific carboxylic acid monomer (A) having an oxyalkylene group are It can be seen that the initial flow value is higher than that of the comparative polymer, and the water content of the cement composition is excellent.
From the comparison between Example 1 and Comparative Example 2 having the same initial flow value, a polymer mainly composed of a monomer unit derived from a specific carboxylic acid monomer (A) having an oxyalkylene group. It can be seen that (1) has excellent retainability because the change in the flow value immediately after kneading and after 30 minutes is small compared to the comparative polymer.
From the above, it became clear that the oxyalkylene group-containing carboxylic acid polymer of the present invention is a polymer that can be suitably used as a cement admixture.

Claims (6)

A dispersant containing an oxyalkylene group-containing carboxylic acid polymer mainly comprising a monomer unit derived from a carboxylic acid monomer (A) having an oxyalkylene group,
The monomer (A) is a polyalkylene represented by the following general formula (2) in at least one of the two COOM groups of the dicarboxylic acid monomer represented by the following general formula (1). Having a structure in which glycol has undergone condensation reaction,
The oxyalkylene group-containing carboxylic acid-based polymer is characterized in that the proportion of monomer units derived from the monomer (A) is 70 mol% or more with respect to 100 mol% of all monomer units. Dispersing agent.

In the formula, any one of R ¹ , R ² and R ³ represents —COOM or — (CH ₂ ) _m COOM, and —COOM or — (CH ₂ ) _m COOM represents an anhydride with another COOM group. May be formed. m represents an integer of 1 to 2. When any one of R ¹ , R ² , and R ³ is —COOM, any one represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the remaining one has 1 to 1 carbon atoms. Represents 10 alkyl groups. When any one of R ¹ , R ² and R ³ is — (CH ₂ ) _m COOM, the remaining two are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. . M is the same or different and represents a hydrogen atom, a monovalent metal, a divalent metal, a trivalent metal, a quaternary ammonium group, or an organic amine group.

In formula, -R < ⁵ > -O- is the same or different and represents a C2-C18 oxyalkylene group. n represents the average addition mole number of an oxyalkylene group, and represents the number of 1-1000. R ⁴ and R ⁶ represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. However, one of R ⁴ and R ⁶ is a hydrogen atom, and the other is an alkyl group having 1 to 20 carbon atoms. A cement admixture comprising an oxyalkylene group-containing carboxylic acid polymer mainly comprising a monomer unit derived from a carboxylic acid monomer having an oxyalkylene group (A),
The monomer (A) is a polyalkylene represented by the following general formula (2) in at least one of the two COOM groups of the dicarboxylic acid monomer represented by the following general formula (1). Having a structure in which glycol has undergone condensation reaction,
The oxyalkylene group-containing carboxylic acid-based polymer contains an oxyalkylene group in which the proportion of monomer units derived from the monomer (A) is 70 mol% or more with respect to 100 mol% of all monomer units. A cement admixture comprising a carboxylic acid polymer.

In the formula, any one of R ¹ , R ² and R ³ represents —COOM or — (CH ₂ ) _m COOM, and —COOM or — (CH ₂ ) _m COOM represents an anhydride with another COOM group. May be formed. m represents an integer of 1 to 2. When any one of R ¹ , R ² , and R ³ is —COOM, any one represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and the remaining one has 1 to 1 carbon atoms. Represents 10 alkyl groups. When any one of R ¹ , R ² and R ³ is — (CH ₂ ) _m COOM, the remaining two are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. . M is the same or different and represents a hydrogen atom, a monovalent metal, a divalent metal, a trivalent metal, a quaternary ammonium group, or an organic amine group.

In formula, -R < ⁵ > -O- is the same or different and represents a C2-C18 oxyalkylene group. n represents the average addition mole number of an oxyalkylene group, and represents the number of 1-1000. R ⁴ and R ⁶ represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. However, one of R ⁴ and R ⁶ is a hydrogen atom, and the other is an alkyl group having 1 to 20 carbon atoms. The monomer (A) has a structure in which the polyalkylene glycol is condensed with any one of two COOM groups of the dicarboxylic acid monomer. Or a cement admixture according to claim 2. The dispersant or cement admixture according to any one of claims 1 to 3, wherein the average added mole number of the oxyalkylene group is 10 to 300. The dispersant or cement admixture according to any one of claims 1 to 4, wherein the oxyalkylene group-containing carboxylic acid polymer has a weight average molecular weight of 5,000 to 500,000. A cement composition comprising the cement admixture according to any one of claims 2 to 5, cement, and water.

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