JP7539864B2 - Solid cement dispersant, its manufacturing method, and cement composition - Google Patents

Description

The present invention relates to a solid cement dispersant, a method for producing the same, and a cement composition.

Lignin is a natural polymeric substance found in trees, accounting for approximately 30% of wood. Lignin is found in large amounts in waste liquor from kraft pulp production (kraft pulp waste liquor) and waste liquor from sulfite pulp production (sulfite pulp waste liquor). In recent years, from the perspective of reducing environmental impact, lignin has tended to attract attention as a biomass resource.

Kraft lignin contained in kraft pulp waste liquor and lignosulfonic acid contained in sulfite pulp waste liquor each have different physical properties and are used for various purposes.
In addition, lignin derivatives obtained by sulfomethylating kraft lignin with sulfite and formaldehyde, lignin derivatives obtained by partially desulfonating lignosulfonic acid or a salt of lignosulfonic acid, and lignin purified products obtained by ultrafiltration are widely used as lignin-based dispersants in a wide range of industrial fields, such as dyes, cement, inorganic pigments, organic pigments, gypsum, coal-water slurries, agricultural chemicals, and ceramics.

Furthermore, with the aim of making effective use of lignin as a biomass resource, lignin derivatives have been proposed that can improve the dispersibility of various dispersed substances, regardless of their application, such as cement, dyes, and oil field drilling mud (see, for example, Patent Document 1).
The lignin derivative disclosed in Patent Document 1 is a reaction product of a lignin sulfonic acid compound and a water-soluble monomer. According to the examples, the lignin derivative is obtained as an aqueous copolymer solution.

JP 2011-240224 A

By the way, when transporting cement dispersants, a solid cement dispersant is considered to be a more preferable form than a liquid cement dispersant from the standpoint of transportation efficiency.

Among dispersants, cement dispersants are sometimes used for the purpose of improving dispersibility (initial dispersibility) immediately after addition, and sometimes for the purpose of maintaining dispersibility (dispersion retention) after a certain time has elapsed since addition. Of these, when a cement dispersant is used for the purpose of maintaining dispersibility (dispersion retention) after a certain time has elapsed since addition, it is necessary to suppress the decrease in dispersibility due to the aggregation of the dispersant over time. Therefore, a solid cement dispersant that takes time to dissolve after addition is considered to be a more preferable form than a liquid cement dispersant that disperses in the system immediately after addition.
Therefore, from the viewpoint of transportation and for the purpose of maintaining dispersion retention, the development of a solid cement dispersant is desired.

On the other hand, when using a cement dispersant to improve the initial dispersibility immediately after addition, it is considered preferable in terms of the manifestation of the effect that the cement dispersant diffuses uniformly immediately after addition. Therefore, a liquid cement dispersant is considered to be in a more preferable form than a solid cement dispersant.

That is, the preferred form of the cement dispersant varies depending on the purpose of use and the viewpoint of transportation.
Therefore, there is a need for the development of a solid cement dispersant that is suitable for maintaining dispersion retention and transportability, and further has excellent initial dispersibility.

The objective of the present invention is to provide a solid cement dispersant that is suitable for maintaining dispersion retention and transportability, and preferably, to provide a solid cement dispersant that, in addition to the above, also has excellent initial dispersibility.

（前記一般式（１）中、Ｒ^１～Ｒ^３は、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。ｐは、０～２の整数を表す。ｑは、０～１の整数を表す。Ａ^１Ｏは、同一又は異なっていてもよい、炭素原子数２～１８のオキシアルキレン基を表す。ｎは、１～３００の整数を表す。Ｒ^４は、水素原子又は炭素原子数１～３０の炭化水素基を表す。）

（前記一般式（２）中、Ｒ^５～Ｒ^７は、それぞれ独立に、水素原子、メチル基、又は－（ＣＨ_２）_ｒＣＯＯＭ^２基を表す。但し、－（ＣＨ_２）_ｒＣＯＯＭ^２基を表す場合、－ＣＯＯＭ^１基又は他の－（ＣＨ_２）_ｒＣＯＯＭ^２基と無水物基を形成してもよい。無水物基を形成する場合、それらの基のＭ^１又はＭ^２は存在しない。Ｍ^１～Ｍ^２は、それぞれ独立に、水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、アルキルアンモニウム基、又は置換アルキルアンモニウム基を表す。ｒは、０～２の整数を表す。）

（前記一般式（３）中、Ｒ^８～Ｒ^１０は、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。Ｒ^１１は、炭素原子数１～４のヘテロ原子を含んでよい炭化水素基を表す。ｓは、０～２の整数を表す。）
〔２〕前記成分（Ｂ）の含有量が、４０重量％以上である、上記〔１〕に記載の固形状セメント分散剤。
〔３〕前記成分（Ａ）の含有量が、１～７０重量％である、上記〔１〕又は〔２〕に記載の固形状セメント分散剤。
〔４〕前記成分（Ｂ）が、リグニンスルホン酸又はその塩の含有量が５０重量％以上である、上記〔１〕～〔３〕のいずれかに記載の固形状セメント分散剤。
〔５〕下記数式（α）で表される溶解度が６．０未満である、上記〔１〕～〔４〕のいずれかに記載の固形状セメント分散剤。

（前記数式（α）中、Ｄａは、固形状セメント分散剤を溶解するのに要した水量（ｍＬ）である。Ｄｂは、溶解した固形状セメント分散剤の乾燥質量（ｇ）である。）
〔６〕下記数式（α）で表される溶解度が６．０以上であり、前記構成単位（Ｉ）が、下記一般式（１－１）で表される単量体に由来する構成単位である、上記〔１〕～〔４〕のいずれかに記載の固形状セメント分散剤。

（前記数式（α）中、Ｄａは、固形状セメント分散剤を溶解するのに要した水量（ｍＬ）である。Ｄｂは、溶解した固形状セメント分散剤の乾燥質量（ｇ）である。）

（前記一般式（１－１）中、ＥＯは、同一又は異なっていてもよい、炭素原子数２～１８のオキシアルキレン基を表す。ｎは、１～３００の整数を表す。）
〔７〕成分（Ａ）：下記一般式（１）で表される単量体に由来する構成単位（Ｉ）、下記一般式（２）で表される単量体に由来する構成単位（ＩＩ）、及び下記一般式（３）で表される単量体に由来する構成単位（ＩＩＩ）からなる群から選択される少なくとも２種の構成単位を有する共重合体、及び成分（Ｂ）：リグニン誘導体、を少なくとも含む液状物を乾燥固形化して、固形状セメント分散剤を製造する、固形状セメント分散剤の製造方法。

（前記一般式（１）中、Ｒ^１～Ｒ^３は、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。ｐは、０～２の整数を表す。ｑは、０～１の整数を表す。Ａ^１Ｏは、同一又は異なっていてもよい、炭素原子数２～１８のオキシアルキレン基を表す。ｎは、１～３００の整数を表す。Ｒ^４は、水素原子又は炭素原子数１～３０の炭化水素基を表す。）

（前記一般式（２）中、Ｒ^５～Ｒ^７は、それぞれ独立に、水素原子、メチル基、又は－（ＣＨ_２）_ｒＣＯＯＭ^２基を表す。但し、－（ＣＨ_２）_ｒＣＯＯＭ^２基を表す場合、－ＣＯＯＭ^１基又は他の－（ＣＨ_２）_ｒＣＯＯＭ^２基と無水物基を形成してもよい。無水物基を形成する場合、それらの基のＭ^１又はＭ^２は存在しない。Ｍ^１～Ｍ^２は、それぞれ独立に、水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、アルキルアンモニウム基、又は置換アルキルアンモニウム基を表す。ｒは、０～２の整数を表す。）

（前記一般式（３）中、Ｒ^８～Ｒ^１０は、それぞれ独立に、水素原子又は炭素原子数１～３のアルキル基を表す。Ｒ^１１は、炭素原子数１～４のヘテロ原子を含んでよい炭化水素基を表す。ｓは、０～２の整数を表す。）
〔８〕上記〔１〕～〔６〕のいずれかに記載の固形状セメント分散剤を含有する、セメント組成物。 As a result of intensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by forming a solid material containing a copolymer composed of predetermined structural units and a lignin derivative, and have completed the present invention. In addition, the present inventors have found that the problem of excellent initial dispersibility can be solved by setting the solubility of the solid material to less than 6.0, and have completed the present invention.
That is, the present inventors provide the following [1] to [8].
[1] A solid cement dispersant comprising at least: component (A): a copolymer having at least two kinds of structural units selected from the group consisting of a structural unit (I) derived from a monomer represented by the following general formula (1), a structural unit (II) derived from a monomer represented by the following general formula (2), and a structural unit (III) derived from a monomer represented by the following general formula (3), and component (B): a lignin derivative.

(In the general formula (1), R ¹ to R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. p represents an integer of 0 to 2. q represents an integer of 0 to 1. ^{A 1} O may be the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300. R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

(In the general formula (2), R ⁵ to R ⁷ each independently represent a hydrogen atom, a methyl group, or a -(CH ₂ ) _r COOM ² group. However, when a -(CH ₂ ) _r COOM ² group is represented, it may form an anhydride group with a -COOM ¹ group or another -(CH ₂ ) _r COOM ² group. When an anhydride group is formed, M ¹ or M ² of the group does not exist. M ¹ to M ² each independently represent a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.)

(In the general formula (3), R ⁸ to R ¹⁰ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹¹ represents a hydrocarbon group having 1 to 4 carbon atoms which may contain a heteroatom. s represents an integer of 0 to 2.)
[2] The solid cement dispersant according to [1] above, wherein the content of the component (B) is 40% by weight or more.
[3] The solid cement dispersant according to [1] or [2] above, wherein the content of the component (A) is 1 to 70% by weight.
[4] The solid cement dispersant according to any one of [1] to [3] above, wherein the component (B) has a lignin sulfonic acid or a salt thereof content of 50% by weight or more.
[5] The solid cement dispersant according to any one of [1] to [4] above, having a solubility represented by the following mathematical formula (α) of less than 6.0.

(In the above formula (α), Da is the amount of water (mL) required to dissolve the solid cement dispersant. Db is the dry mass (g) of the dissolved solid cement dispersant.)
[6] The solid cement dispersant according to any one of [1] to [4] above, wherein the solubility represented by the following formula (α) is 6.0 or more, and the structural unit (I) is a structural unit derived from a monomer represented by the following general formula (1-1).

(In the above formula (α), Da is the amount of water (mL) required to dissolve the solid cement dispersant. Db is the dry mass (g) of the dissolved solid cement dispersant.)

(In the general formula (1-1), EO may be the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300.)
[7] A method for producing a solid cement dispersant, comprising drying and solidifying a liquid containing at least component (A): a copolymer having at least two kinds of structural units selected from the group consisting of structural units (I) derived from a monomer represented by the following general formula (1), structural units (II) derived from a monomer represented by the following general formula (2), and structural units (III) derived from a monomer represented by the following general formula (3), and component (B): a lignin derivative.

(In the general formula (1), R ¹ to R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. p represents an integer of 0 to 2. q represents an integer of 0 to 1. ^{A 1} O may be the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300. R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

(In the general formula (2), R ⁵ to R ⁷ each independently represent a hydrogen atom, a methyl group, or a -(CH ₂ ) _r COOM ² group. However, when a -(CH ₂ ) _r COOM ² group is represented, it may form an anhydride group with a -COOM ¹ group or another -(CH ₂ ) _r COOM ² group. When an anhydride group is formed, M ¹ or M ² of the group does not exist. M ¹ to M ² each independently represent a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.)

(In the general formula (3), R ⁸ to R ¹⁰ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹¹ represents a hydrocarbon group having 1 to 4 carbon atoms which may contain a heteroatom. s represents an integer of 0 to 2.)
[8] A cement composition comprising the solid cement dispersant according to any one of [1] to [6] above.

According to the present invention, it is possible to provide a solid cement dispersant that is suitable for maintaining dispersion retention and transportability, and preferably a solid cement dispersant that in addition to the above also has excellent initial dispersibility.

The present invention will be described in detail below based on preferred embodiments thereof.
In this specification, the term "AA-BB" means AA or higher and BB or lower, and the term "(meth)acrylic" means acrylic and/or methacrylic.

[1. Solid cement dispersant]
The solid cement dispersant of the present invention contains at least component (A): a copolymer having a predetermined structural unit, and component (B): a lignin derivative.
Since solid cement dispersants gradually dissolve after being added, even if they aggregate, they are thought to have excellent dispersion retention properties due to the newly released cement dispersant that dissolves.
The present inventors have investigated solid cement dispersants and found that a solid cement dispersant containing a copolymer having a predetermined structural unit and a lignin derivative has a high dispersion retention rate, which led to the completion of the present invention.

In addition, as described above, a solid cement dispersant with low solubility dissolves more gradually from the time of addition than a solid cement dispersant with high solubility, and therefore, even if the cement dispersant aggregates, it is considered to have excellent dispersion retention properties due to the newly released cement dispersant that dissolves.
The present inventors have studied solid cement dispersants and have unexpectedly found that a solid cement dispersant containing a copolymer having a predetermined structural unit and a lignin derivative has a high dispersion retention rate when the solubility represented by the mathematical formula (α) is set to a high value of 6.0 or more, and have thus completed the present invention.

Furthermore, since the cement dispersant disperses uniformly immediately after being added, it is believed that the initial dispersibility is superior in a liquid form than in a solid form. On the other hand, in consideration of maintaining dispersion retention and transportability, a solid cement dispersant is preferable.
The present inventors have investigated solid cement dispersants having excellent initial dispersibility, and have found that a cement dispersant containing a copolymer having a predetermined structural unit and a lignin derivative and having a solubility of less than 6.0 represented by the mathematical formula (α) is suitable for maintaining dispersion retention and transportability, and is also excellent in initial dispersibility, thereby completing the present invention.

The term "solid" in the solid cement dispersant means that the water content of the cement dispersant is 50% by mass or less. The water content of the cement dispersant is preferably 30% by mass or less, and more preferably 10% by mass or less.
The moisture content of the cement dispersant can be measured using an infrared moisture meter (manufactured by Kett Electric Laboratory, Ltd.).

The solubility of the solid cement dispersant is not particularly limited.
In one embodiment, the solubility of the solid cement dispersant is preferably 6.0 or more, more preferably 7.0 or more. Note that the upper limit of the solubility in one embodiment is usually 8.0 or less.
In another embodiment, the solubility of the solid cement dispersant is preferably less than 6.0, more preferably less than 4.0, and even more preferably 2.0 or less. Note that the lower limit of the solubility in another embodiment is usually 0.5 or more.
The solubility is a value specified by the above formula (α). The water used to dissolve the solid cement dispersant when specifying Da is deionized water at a temperature of 10 to 20° C. In this specification, the criterion for dissolution is that no solid matter adheres to the rotor after stirring with a magnetic stirrer for 30 seconds.

[1-1. Component (A)]
The solid cement dispersant of the present invention contains at least component (A).
Component (A) is a copolymer having at least two types of structural units selected from the group consisting of structural units (I) derived from a monomer represented by general formula (1), structural units (II) derived from a monomer represented by general formula (2), and structural units (III) derived from a monomer represented by general formula (3).

In the solid cement dispersant of the present invention, the content of component (A) is preferably 1 to 70% by weight, more preferably 1 to 60% by weight, even more preferably 1 to 50% by weight, and even more preferably 20 to 50% by weight. When the content of component (A) is within this range, a solid cement dispersant having good water solubility after drying can be obtained. Therefore, a cement composition with good usability can be obtained.
Details of each constituent unit are given below.

(Structural Unit (I))
The structural unit (I) is a structural unit derived from a monomer represented by the following general formula (1).

In general formula (1), R ¹ to R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. p represents an integer of 0 to 2. q represents an integer of 0 to 1. ^{A 1} O may be the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300. R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.
R ¹ is preferably a hydrogen atom. R ² is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group. R ³ is preferably a hydrogen atom.

In general formula (1), A ¹ O may be the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. Examples of the oxyalkylene group (alkylene glycol unit) include an oxyethylene group (ethylene glycol unit), an oxypropylene group (propylene glycol unit), and an oxybutylene group (butylene glycol unit). Of these, an oxyethylene group and an oxypropylene group are preferred.

The above "may be the same or different" means that when a plurality of A ¹ O's are contained in the general formula (1) (when n is 2 or more), each A ¹ O's may be the same oxyalkylene group or may be different (two or more kinds) oxyalkylene groups. When a plurality of A ¹ O's are contained in the general formula (1), an embodiment in which two or more oxyalkylene groups selected from the group consisting of an oxyethylene group, an oxypropylene group, and an oxybutylene group are mixed can be mentioned. More specifically, an embodiment in which an oxyethylene group and an oxypropylene group are mixed, or an embodiment in which an oxyethylene group and an oxybutylene group are mixed, is preferable, and an embodiment in which an oxyethylene group and an oxypropylene group are mixed is more preferable.
In an embodiment in which different oxyalkylene groups are mixed, the addition of two or more types of oxyalkylene groups may be in a block form or a random form.

In general formula (1), n is the average number of moles of oxyalkylene groups added and represents an integer of 1 to 300. n is preferably 1 to 200. The average number of moles added means the average number of moles of oxyalkylene groups added to 1 mole of monomer.

In general formula (1), ^R4 represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. ^R4 is preferably a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms, and even more preferably a hydrogen atom or a methyl group. If the number of carbon atoms of ^R4 is within this range, the number of carbon atoms will not be too large, and the dispersibility of the cement composition will be excellent.

Examples of the method for producing the monomer represented by the general formula (1) include a method in which 1 to 300 moles of alkylene oxide are added to an unsaturated alcohol such as allyl alcohol, methallyl alcohol, 3-methyl-3-buten-1-ol, etc. Examples of monomers that can be produced by this method include (poly)ethylene glycol allyl ether, (poly)ethylene glycol methallyl ether, (poly)ethylene glycol 3-methyl-3-butenyl ether, (poly)ethylene glycol (poly)propylene glycol allyl ether, (poly)ethylene glycol (poly)propylene glycol methallyl ether, (poly)ethylene (poly)propylene glycol allyl ether, (poly)ethylene (poly)propylene glycol methallyl ether, (poly)ethylene (poly)propylene glycol 3-methyl-3-butenyl ether, (poly)ethylene (poly)butylene glycol allyl ether, (poly)ethylene (poly)butylene glycol methallyl ether, (poly)ethylene (poly) butylene glycol 3-methyl-3-butenyl ether, methoxy(poly)ethylene glycol allyl ether, methoxy(poly)ethylene glycol methallyl ether, methoxy(poly)ethylene glycol 3-methyl-3-butenyl ether, methoxy(poly)ethylene (poly)propylene glycol allyl ether, methoxy(poly)ethylene (poly)propylene glycol methallyl ether, methoxy(poly)ethylene (poly)propylene glycol 3-methyl-3-butenyl ether, methoxy(poly)ethylene (poly)butylene glycol allyl ether, methoxy(poly)ethylene (poly)butylene glycol methallyl ether, methoxy(poly)ethylene (poly)butylene glycol 3-methyl-3-butenyl ether.
Among these, from the viewpoint of the balance between hydrophilicity and hydrophobicity, (poly)ethylene glycol (meth)allyl ether, (poly)ethylene glycol (poly)propylene glycol (meth)allyl ether, (poly)ethylene (poly)propylene glycol (meth)allyl ether, (poly)ethylene glycol 3-methyl-3-butenyl ether, and (poly)ethylene (poly)propylene glycol 3-methyl-3-butenyl ether are preferred.

Another method for producing the monomer represented by general formula (1) is to esterify an unsaturated monocarboxylic acid such as (meth)acrylic acid with a (poly)alkylene glycol such as (poly)ethylene glycol, (poly)ethylene (poly)propylene glycol, (poly)ethylene (poly)butylene glycol, methoxy(poly)ethylene glycol, methoxy(poly)ethylene (poly)propylene glycol, methoxy(poly)ethylene (poly)butylene glycol, etc. Monomers that can be produced by this method include, for example, (poly)alkylene glycol (meth)acrylates such as (poly)ethylene glycol (meth)acrylate, (poly)ethylene (poly)propylene glycol (meth)acrylate, (poly)ethylene (poly)butylene glycol (meth)acrylate, etc.; and methoxy(poly)alkylene glycol (meth)acrylates such as methoxy(poly)ethylene glycol (meth)acrylate, methoxy(poly)ethylene (poly)propylene glycol (meth)acrylate, methoxy(poly)ethylene (poly)butylene glycol (meth)acrylate, etc.
Among these, (poly)alkylene glycol (meth)acrylate and methoxy(poly)ethylene glycol (meth)acrylate are preferred, and methoxy(poly)ethylene glycol (meth)acrylate is more preferred.

When the copolymer has structural unit (I), it may have only one type of structural unit (I), or it may have two or more types of structural unit (I) derived from different monomers.

When the solubility of the solid cement dispersant is 6.0 or more, it is preferable that the constituent unit is derived from a monomer represented by the following general formula (1-1).

In general formula (1-1), EO may be the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300.

In the general formula (1-1), EO may be the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. Examples of the oxyalkylene group include an oxyethylene group (ethylene glycol), an oxypropylene group (propylene glycol), and an oxybutylene group (butylene glycol).
Of these, the oxyalkylene group is preferably an oxyethylene group (ethylene glycol) or an oxypropylene group (propylene glycol).

The above phrase "may be the same or different" means that when a plurality of EOs are contained in general formula (1-1) (when n is 2 or more), the plurality of EOs may be the same oxyalkylene group or different (two or more types) oxyalkylene groups.
In the case where multiple EOs are contained in general formula (1), the embodiment includes a mixture of two or more oxyalkylene groups selected from the group consisting of oxyethylene group (ethylene glycol unit), oxypropylene group (propylene glycol unit) and oxybutylene group (butylene glycol unit).Among these, the embodiment in which oxyethylene group (ethylene glycol unit) and oxypropylene group (propylene glycol unit) are mixed or the embodiment in which oxyethylene group (ethylene glycol unit) and oxybutylene group (butylene glycol unit) are mixed is preferred, and the embodiment in which oxyethylene group (ethylene glycol unit) and oxypropylene group (propylene glycol unit) are mixed is more preferred.
In the case where oxyethylene groups and oxypropylene groups are mixed, the ratio of the average number of moles of oxyethylene groups to the average number of moles of oxypropylene groups ((average number of moles of oxyethylene groups)/(average number of moles of oxypropylene groups)) is preferably (50 to 99.9)%/(0.1 to 50)%.
In an embodiment in which different oxyalkylene groups are mixed, the addition of two or more types of oxyalkylene groups may be in a block form or a random form.

In general formula (1-1), n is the average number of moles of oxyalkylene groups added, and is a number from 1 to 300. n is preferably from 1 to 200, more preferably from 1 to 70, even more preferably from 5 to 70, and even more preferably from 8 to 70.

A method for producing the monomer represented by general formula (1-1) includes, for example, adding 1 to 200 moles of alkylene oxide to an unsaturated alcohol such as allyl alcohol, methallyl alcohol, or 3-methyl-3-buten-1-ol.

Monomers that can be produced by this method include, for example, (poly)ethylene glycol allyl ether, (poly)ethylene glycol methallyl ether, (poly)ethylene glycol 3-methyl-3-butenyl ether, (poly)ethylene (poly)propylene glycol allyl ether, (poly)ethylene (poly)propylene glycol methallyl ether, (poly)ethylene (poly)propylene glycol 3-methyl-3-butenyl ether, (poly)ethylene (poly)butylene glycol allyl ether, (poly)ethylene (poly)butylene glycol methallyl ether, (poly)ethylene (poly)butylene glycol 3-methyl-3-butenyl ether, (poly)ethylene glycol (poly)propylene glycol monoallyl ether, ethylene oxide adduct of 3-methyl-3-buten-1-ol, and ethylene oxide propylene oxide adduct of 3-methyl-3-buten-1-ol.

Another method for producing the monomer represented by general formula (1-1) is to esterify an unsaturated monocarboxylic acid such as (meth)acrylic acid with a (poly)alkylene glycol such as (poly)ethylene glycol, (poly)ethylene (poly)propylene glycol, or (poly)ethylene (poly)butylene glycol.

Examples of monomers that can be produced by this method include (poly)alkylene glycol (meth)acrylates such as (poly)ethylene glycol (meth)acrylate, (poly)ethylene (poly)propylene glycol (meth)acrylate, and (poly)ethylene (poly)butylene glycol (meth)acrylate.

Because of a good balance between hydrophilicity and hydrophobicity, the monomer represented by general formula (1-1) preferably includes at least one selected from the group consisting of (poly)ethylene glycol (meth)allyl ether, (poly)ethylene glycol (poly)propylene glycol monoallyl ether, an ethylene oxide adduct of 3-methyl-3-buten-1-ol, and an ethylene oxide propylene oxide adduct of 3-methyl-3-buten-1-ol, and more preferably is any one of them.
As described above, the average number of moles of the oxyalkylene group (polyalkylene glycol unit) added in the monomer represented by the general formula (1-1) is preferably 1 to 200, more preferably 1 to 70, even more preferably 5 to 70, and still more preferably 8 to 70.

Monomer (I) may be one type of monomer represented by general formula (1-1) or a combination of two or more types.

(Structural unit (II))
The structural unit (II) is a structural unit derived from a monomer represented by the following general formula (2).

In general formula (2), R ⁵ to R ⁷ each independently represent a hydrogen atom, a methyl group, or a -(CH ₂ ) _r COOM ² group. However, when a -(CH ₂ ) _r COOM ² group is represented, it may form an anhydride group with a -COOM ¹ group or another -(CH ₂ ) _r COOM ² group. When an anhydride group is formed, M ¹ or M ² of the group does not exist. M ¹ to M ² each independently represent a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.
^R5 is preferably a hydrogen atom. ^R6 is preferably a hydrogen atom, ^a methyl group or ( _CH2 ) _rCOOM2 . ^R7 is preferably a hydrogen atom.

M ¹ and M ² may be the same or different and are a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group or a substituted alkylammonium group. M ¹ and M ² are preferably a hydrogen atom, an alkali metal or an alkaline earth metal, respectively.

r represents an integer from 0 to 2. r is preferably 0 or 1, and more preferably 0.

Examples of monomers represented by general formula (2) include unsaturated monocarboxylic acid monomers and unsaturated dicarboxylic acid monomers. Specific examples of unsaturated monocarboxylic acid monomers include acrylic acid, methacrylic acid, crotonic acid, and the like, and their monovalent metal salts, ammonium salts, and organic amine salts. Specific examples of unsaturated dicarboxylic acids include maleic acid, itaconic acid, citraconic acid, fumaric acid, and the like, and their monovalent metal salts, ammonium salts, and organic amine salts, or their anhydrides. As monomers represented by general formula (2), acrylic acid, methacrylic acid, and maleic acid are preferred.

When the copolymer has structural unit (II), it may have only one type of structural unit (II), or it may have two or more types of structural unit (II) derived from different monomers.

(Structural unit (III))
The structural unit (III) is a structural unit derived from a monomer represented by the following general formula (3).

In formula (3), R ⁸ to R ¹⁰ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹¹ represents a hydrocarbon group having 1 to 4 carbon atoms which may contain a heteroatom. s represents an integer of 0 to 2.
Examples of the alkyl group having 1 to 3 carbon atoms are the same as those for R ¹ to R ^3. R ⁸ is preferably a hydrogen atom. R ⁹ is preferably a hydrogen atom. R ¹⁰ is preferably a hydrogen atom.

In the general formula (3), R ¹¹ represents a hydrocarbon group having 1 to 4 carbon atoms, which may contain a heteroatom. The number of carbon atoms is preferably 1 to 3, more preferably 2 to 3, and even more preferably 3. Examples of the heteroatom include an oxygen atom, a nitrogen atom, a phosphorus atom, and a silicon atom. Among these, an oxygen atom is preferable. Examples of the hydrocarbon group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, an isobutyl group, and a sec-butyl group. The number of heteroatoms contained in R ¹¹ may be one, or may be two or more. When two or more heteroatoms are contained, the respective heteroatoms may be the same or different from each other.

R ¹¹ is preferably a hydrocarbon group containing a heteroatom and having 1 to 4 carbon atoms, more preferably a hydrocarbon group containing an oxygen atom and having 1 to 4 carbon atoms. Examples of such groups include a 2-hydroxyethyl group, a 2-hydroxypropyl group, a 4-hydroxybutyl group, and a glyceryl group. Of these, the 2-hydroxyethyl group and the 2-hydroxypropyl group are preferred.

In general formula (3), s represents an integer from 0 to 2. s is preferably 0.

Examples of monomers represented by general formula (3) include monoesters of unsaturated monocarboxylic acids. Examples of unsaturated monocarboxylic acid monoesters include methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and glyceryl (meth)acrylate. Of these, 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate are preferred.

When the copolymer has structural unit (III), it may have only one type of structural unit (III), or it may have two or more types of structural unit (III) derived from different monomers.

When the copolymer has at least two structural units selected from the group consisting of the structural units (I) to (III) above, compatibility with component (B) is improved, and component (B) can be more uniformly dispersed in the cement composition.

The copolymer may have structural unit (IV) in addition to structural units (I) to (III).

(Structural unit (IV))
The structural unit (IV) is a structural unit derived from a monomer copolymerizable with the monomers represented by the above general formulas (1) to (3). The monomers copolymerizable with the monomers represented by the above general formulas (1) to (3) are structurally distinct from the monomers represented by the above general formulas (1) to (3). The monomers constituting the structural unit (IV) are not particularly limited, and examples thereof include the following monomers:
These monomers can be used alone or in combination of two or more.

A monomer represented by general formula (IV-1);

Examples of monomers represented by general formula (IV-1) include 3- and 3'-allyl-substituted bisphenols such as 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, and 4,4'-dihydroxydiphenylsulfone.

A monomer represented by general formula (IV-2):

Examples of monomers represented by the above general formula (IV-2) include 3-allyl-substituted bisphenols such as 4,4'-dihydroxydiphenylpropane, 4,4'-dihydroxydiphenylmethane, and 4,4'-dihydroxydiphenylsulfone.

A monomer represented by general formula (IV-3):

An example of a monomer represented by general formula (IV-3) is allylphenol.

Half esters and diesters of unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, fumaric acid, itaconic acid, and citraconic acid with alcohols having 1 to 30 carbon atoms;

Half amides and diamides of the above unsaturated dicarboxylic acids and amines having 1 to 30 carbon atoms;

Half esters, half amides, diesters, and diamides of (poly)oxyalkylene alkyl ethers or (poly)oxyalkylene alkyl amines in which 1 to 500 moles of alkylene oxide having 2 to 18 carbon atoms is added to the above alcohols or amines and the above unsaturated dicarboxylic acids;

Half esters and diesters of the above unsaturated dicarboxylic acids and glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 moles of addition of these glycols;

Half amides of maleamic acid and glycols having 2 to 18 carbon atoms or polyalkylene glycols having 2 to 500 moles of these glycols;

(Poly)ethylene glycol mono(meth)acrylate, (poly)propylene glycol mono(meth)acrylate, (poly)butylene glycol mono(meth)acrylates (excluding monomers represented by general formulas (1) to (3)) in which 1 to 500 moles of alkylene oxide having 2 to 18 carbon atoms are added to unsaturated monocarboxylic acids such as (meth)acrylic acid;

(Poly)alkylene glycol di(meth)acrylates such as triethylene glycol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, (poly)ethylene glycol (poly)propylene glycol di(meth)acrylate;

Polyfunctional (meth)acrylates such as hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and trimethylolpropane di(meth)acrylate;

(Poly)alkylene glycol dimaleates such as triethylene glycol dimaleate and polyethylene glycol dimaleate;

Unsaturated sulfonic acids such as vinyl sulfonate, (meth)allyl sulfonate, 2-(meth)acryloxyethyl sulfonate, 3-(meth)acryloxypropyl sulfonate, 3-(meth)acryloxy-2-hydroxypropyl sulfonate, 3-(meth)acryloxy-2-hydroxypropyl sulfophenyl ether, 3-(meth)acryloxy-2-hydroxypropyloxysulfobenzoate, 4-(meth)acryloxybutyl sulfonate, (meth)acrylamidomethyl sulfonic acid, (meth)acrylamidoethyl sulfonic acid, 2-methylpropanesulfonic acid (meth)acrylamide, and styrenesulfonic acid, as well as their monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts;

Amides of unsaturated monocarboxylic acids such as methyl (meth)acrylamide and amines having 1 to 30 carbon atoms;

Vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene, and p-methylstyrene;

Alkanediol mono(meth)acrylates such as 1,5-pentanediol mono(meth)acrylate and 1,6-hexanediol mono(meth)acrylate (excluding monomers represented by general formula (3));

Dienes such as butadiene, isoprene, 2-methyl-1,3-butadiene, and 2-chloro-1,3-butadiene;

Unsaturated amides such as (meth)acrylamide, (meth)acrylalkylamide, N-methylol (meth)acrylamide, and N,N-dimethyl (meth)acrylamide;

Unsaturated cyanides such as (meth)acrylonitrile and α-chloroacrylonitrile;

Unsaturated esters such as vinyl acetate and vinyl propionate;

Unsaturated amines such as aminoethyl (meth)acrylate, methylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dibutylaminoethyl (meth)acrylate, and vinylpyridine (excluding monomers represented by general formula (3));

Divinyl aromatics such as divinylbenzene; cyanurates such as triallyl cyanurate;

Allyls such as (meth)allyl alcohol and glycidyl (meth)allyl ether;

Vinyl ethers or allyl ethers such as methoxypolyethylene glycol monovinyl ether, polyethylene glycol monovinyl ether, methoxypolyethylene glycol mono(meth)allyl ether, and polyethylene glycol mono(meth)allyl ether (excluding the monomer represented by the general formula (1));

Siloxane derivatives such as polydimethylsiloxane propylaminomaleamic acid, polydimethylsiloxane aminopropylene aminomaleamic acid, polydimethylsiloxane-bis-(propylaminomaleamic acid), polydimethylsiloxane-bis-(dipropyleneaminomaleamic acid), polydimethylsiloxane-(1-propyl-3-acrylate), polydimethylsiloxane-(1-propyl-3-methacrylate), polydimethylsiloxane-bis-(1-propyl-3-acrylate), polydimethylsiloxane-bis-(1-propyl-3-methacrylate) (excluding the monomer represented by general formula (3)).

The copolymer may have only one type of structural unit (IV), or may have two or more types of structural units (IV) derived from different monomers.

In the copolymer, each of the structural units (I) to (IV) may be a structural unit composed of one type of monomer, or may be a structural unit composed of a combination of two or more types of monomers. Among these, the copolymer is preferably a copolymer that is a combination of the structural unit (I) and the structural unit (II), or a copolymer that is a combination of the structural units (I) to (III).

(Method of Preparing Copolymer)
The copolymer can be prepared by copolymerizing the respective predetermined monomers by a known method, such as polymerization in a solvent or bulk polymerization.

Examples of solvents used in the polymerization in a solvent include water; lower alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol; aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as cyclohexane and n-hexane; esters such as ethyl acetate; and ketones such as acetone and methyl ethyl ketone. From the viewpoint of the solubility of the raw material monomers and the resulting copolymer, it is preferable to use at least one of water and lower alcohols, and it is more preferable to use water.

When the polymerization reaction is carried out in a solvent, each monomer and the polymerization initiator may be continuously dripped into a reaction vessel, or a mixture of each monomer and the polymerization initiator may be continuously dripped into a reaction vessel. Alternatively, the reaction vessel may be charged with a solvent, and the mixture of the monomers and the solvent and the polymerization initiator solution may be continuously dripped into the reaction vessel, or some or all of the monomers may be charged into the reaction vessel, and the polymerization initiator may be continuously dripped into the reaction vessel.

The polymerization initiator that can be used in the polymerization reaction is not particularly limited. Examples of polymerization initiators that can be used when performing a polymerization reaction in an aqueous solvent include persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate; and water-soluble peroxides such as t-butyl hydroperoxide and hydrogen peroxide. In this case, accelerators such as L-ascorbic acid, sodium hydrogen sulfite, Mohr's salt, and sodium formaldehyde sulfoxylate may be used in combination. Examples of polymerization initiators that can be used when performing a polymerization reaction in an organic solvent such as a lower alcohol, an aromatic hydrocarbon, an aliphatic hydrocarbon, an ester, or a ketone include peroxides such as benzoyl peroxide and lauryl peroxide; hydroperoxides such as cumene peroxide; and azo compounds such as azobisisobutyronitrile. In this case, accelerators such as amine compounds may be used in combination. The polymerization initiator that can be used when performing a polymerization reaction in a water-lower alcohol mixed solvent may be appropriately selected from the above-mentioned polymerization initiators or combinations of polymerization initiators and accelerators.
The polymerization temperature varies depending on the polymerization conditions such as the type of the solvent and the polymerization initiator used, but is usually 40 to 120°C.

In the polymerization reaction, the molecular weight can be adjusted by using a chain transfer agent as necessary. Examples of the chain transfer agent include known thiol compounds such as mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl thioglycolate, and 2-mercaptoethanesulfonic acid; phosphorous acid, hypophosphorous acid, or salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, hydrogen sulfite, dithionous acid, metabisulfite, or salts thereof (sodium sulfite, potassium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite, sodium dithionite, potassium dithionite, sodium metabisulfite, potassium metabisulfite, etc.), lower oxides or salts thereof.
These chain transfer agents may be used alone or in combination of two or more.

When a polymerization reaction is carried out in an aqueous solvent to obtain a copolymer, the pH during the polymerization reaction is usually strongly acidic due to the influence of a monomer having an unsaturated bond. However, this may be adjusted to an appropriate pH. If pH adjustment is required during the polymerization reaction, the pH may be adjusted using an acidic substance such as phosphoric acid, sulfuric acid, nitric acid, alkyl phosphoric acid, alkyl sulfuric acid, alkyl sulfonic acid, or (alkyl)benzenesulfonic acid. Among these acidic substances, phosphoric acid is preferably used because of its pH buffering effect. However, in order to eliminate the instability of the ester bond of the ester monomer, it is preferable to carry out the polymerization reaction at a pH of 2 to 7. In addition, there is no particular limitation on the alkaline substance that can be used to adjust the pH, and alkaline substances such as NaOH and Ca(OH) ₂ are common. The pH adjustment may be performed on the monomer before the polymerization reaction, or on the copolymer solution after the polymerization reaction. In addition, a part of the alkaline substance may be added before the polymerization reaction to carry out polymerization, and then the pH of the copolymer may be further adjusted (for example, adjusted to a pH of 3 to 7).

The copolymer may be prepared as a liquid. Examples of liquid solvents include aqueous solvents. Examples of aqueous solvents include water, alcohols having 1 to 6 carbon atoms (ethyl alcohol, methyl alcohol, ethylene glycol, diethylene glycol, etc.), and ketones having 1 to 6 carbon atoms (methyl isobutyl ketone, acetone, etc.). These aqueous solvents may be used alone or in combination of two or more. Water is preferred as the aqueous solvent.
The lower limit of the solid content concentration in the copolymer is preferably 5% by weight or more, more preferably 15% by weight or more, and the upper limit is preferably 70% by weight or less, more preferably 65% by weight or less.

Component (A) may contain at least one monomer selected from the group consisting of the above general formulas (1) to (3), which are raw materials for the copolymer. When obtaining the copolymer, treatments such as removal of the reaction solvent, concentration, purification, etc. may be carried out as necessary. These treatment methods may be conventionally known methods.

The lower limit of the weight average molecular weight (Mw) of the copolymer is preferably 5000 or more, more preferably 6000 or more. By using a copolymer having this weight average molecular weight as component (A), the dispersibility of the cement composition can be fully exhibited. Therefore, the fluidity or workability can be improved. The upper limit of the weight average molecular weight is preferably 60,000 or less, more preferably 50,000 or less. By using a copolymer having this weight average molecular weight as component (A), the aggregation action of particles in the cement composition can be suppressed, and the workability can be improved. The weight average molecular weight is preferably 5,000 to 60,000, more preferably 6,000 to 50,000.

The lower limit of the molecular weight distribution (Mw/Mn) of the copolymer is preferably 1.0 or more, more preferably 1.2 or more. The upper limit is preferably 3.0 or less, more preferably 2.5 or less. The molecular weight distribution is preferably in the range of 1.0 to 3.0, more preferably in the range of 1.2 to 3.0, and even more preferably in the range of 1.2 to 2.5.

The weight average molecular weight can be measured by a known method using gel permeation chromatography (GPC) in terms of polyethylene glycol. The measurement conditions for GPC are not particularly limited, and the following conditions can be mentioned, for example. The weight average molecular weight in the examples described later is a value measured under these conditions.
Measurement equipment: Tosoh Columns used: Shodex Column OH-pak SB-806HQ, SB-804HQ, SB-802.5HQ
Eluent: 0.05 mM sodium nitrate/acetonitrile 8/2 (v/v)
Standard substance: polyethylene glycol (manufactured by Tosoh Corporation or GL Sciences Co., Ltd.)
Detector: Differential refractometer (Tosoh Corporation)
Calibration curve: Polyethylene glycol standard

[1-2. Component (B)]
The solid cement dispersant of the present invention contains component (B).
Component (B) is a lignin derivative. Here, lignin sulfonic acid refers to a compound in which at least a portion of lignin or a derivative thereof is substituted with a sulfonic acid (salt) group.

It is difficult to uniformly specify the chemical structure of a lignin derivative using a general formula or the like. This is because lignin, which is the skeleton of the lignin sulfonic acid compound that constitutes the lignin derivative, has a very complex molecular structure. Furthermore, lignin derivatives include reducing sugars and/or sugar-modified products, and inorganic salts in addition to lignin sulfonic acid or its salts. The presence of reducing sugars and/or sugar-modified products can also make it difficult to uniformly specify the structure.

"Reducing sugars" refers to sugars that exhibit reducing properties, and are sugars that generate aldehyde or ketone groups in a basic solution. Examples of reducing sugars include all monosaccharides; disaccharides such as maltose, lactose, arabinose, and invert sugars of sucrose; and polysaccharides. Reducing sugars generally include cellulose, hemicellulose, and their decomposition products. Examples of decomposition products of cellulose and hemicellulose include monosaccharides such as rhamnose, galactose, arabinose, xylose, glucose, mannose, and fructose; and oligosaccharides such as xylooligosaccharides and cellooligosaccharides.
The term "sugar modified product" refers to a product obtained by chemically modifying sugar, such as oxidation, sulfonation, etc. Examples of sugar modified products include sugar derivatives in which functional groups such as hydroxyl groups, aldehyde groups, carbonyl groups, and sulfo groups have been introduced into the sugar skeleton, and compounds in which two or more of the sugar derivatives (two types) are bound together.

In the solid cement dispersant of the present invention, the content of component (B) is preferably 40% by weight or more, more preferably 45% by weight or more, and even more preferably 50% by weight or more. When the content of component (B) is 40% by weight or more, a solid cement dispersant having good powder fluidity can be obtained in high yield. In addition, although there is no particular limit to the upper limit, it is usually 90% by weight or less, preferably 80% by weight or less, and more preferably 70% by weight or less.

The content of lignin sulfonic acid or its salt in the lignin derivative is preferably 50% by weight or more, more preferably 60% by weight or more, even more preferably 70% by weight or more, and even more preferably 80% by weight or more. By using a lignin derivative with a content of lignin sulfonic acid or its salt in this range, the initial dispersibility is superior in the solid form to that in the liquid form when used as a cement dispersant. The upper limit is not particularly limited, but is usually 98% by weight or less, and preferably 90% by weight or less.
The content of lignin sulfonic acid or a salt thereof in the lignin derivative can be calculated by calculating the value of methoxyl groups according to the quantitative determination method of methoxyl groups by the Viebock and Schwappach method described in Methods in Lignin Chemistry (edited by Junzo Nakano, Uni Publishing Co., Ltd.) and converting the value into the lignin content.

The content of reducing sugars and/or sugar-modified substances in the lignin derivative is preferably 50% by weight or less, more preferably 20% by weight or less. By using a lignin derivative having a content of reducing sugars and/or sugar-modified substances in this range, the initial dispersibility can be improved when the lignin derivative is used as a cement dispersant. The lower limit is not particularly limited, but is usually 1% by weight or more.
The content of reducing sugars and/or modified sugars in the lignin derivative can be calculated by subtracting the content of lignosulfonic acid or a salt thereof and the content of inorganic salts from the total weight.

The lignin derivative may be prepared or may be a commercially available product. Here, the preparation method of the lignin derivative is exemplified below. However, the lignin derivative is not limited to the one prepared by the preparation method described below.

(Method for preparing lignin derivative)
The lignin derivative can be prepared, for example, by subjecting a lignocellulosic raw material to a sulfite treatment, preferably by subjecting a lignocellulosic raw material to a sulfite cooking treatment.

The lignocellulose raw material is not particularly limited as long as it contains lignocellulose in the structure, and examples thereof include pulp raw materials such as wood and non-wood.
Examples of wood include coniferous wood such as Yezo spruce, red pine, cedar, and cypress; and broad-leaved wood such as white birch and beech. The age and part of the tree from which the wood is harvested do not matter. Therefore, wood harvested from trees of different ages or from different parts of a tree may be used in combination.
Non-wood materials include, for example, bamboo, kenaf, reed, and rice.
The lignocellulosic raw material may be one of these materials alone or two or more of them may be combined.

Sulfite treatment is a process in which at least one of sulfurous acid and a sulfite salt is brought into contact with lignocellulosic raw materials to obtain an intermediate product. The conditions for the sulfite treatment are not particularly limited, and may be any conditions under which a sulfonic acid (salt) group can be introduced to the α-carbon atom of the side chain of the lignin contained in the lignocellulosic raw material.

The sulfite treatment is preferably carried out by a sulfite cooking method, which allows more quantitative sulfonation of the lignin in the lignocellulosic raw material.
The sulfite cooking method is a method in which lignocellulosic raw materials are reacted at high temperatures in a solution of at least one of sulfurous acid and a sulfite salt (e.g., an aqueous solution: cooking liquor). This method has been established and is being used industrially as a method for producing sulfite pulp. Therefore, by carrying out the sulfite treatment by the sulfite cooking method, it is possible to improve the economic efficiency and ease of implementation.

When sulfite cooking is performed, examples of sulfite salts include magnesium salts, calcium salts, sodium salts, and ammonium salts.

The sulfurous acid (SO ₂ ) concentration in the solution of at least any one of sulfurous acid and a sulfite salt is not particularly limited, but the ratio of the mass (g) of SO ₂ to 100 mL of the solution is preferably 1 g/100 mL or more.

The pH value of the sulfurous acid treatment is not particularly limited, but is preferably 10 or less, and more preferably 5 or less when sulfite cooking is performed. The lower limit of the pH value is preferably 0.1 or more, and more preferably 0.5 or more when sulfite cooking is performed. The pH value during the sulfurous acid treatment is preferably 0.1 to 10, and more preferably 0.5 to 5 when sulfite cooking is performed.

The temperature of the sulfite treatment is not particularly limited, but is preferably 170°C or less. The lower limit is preferably 70°C or more.

In the sulfite treatment, it is preferable to add a compound that supplies a counter cation (salt). By adding a compound that supplies a counter cation, the pH value in the sulfite treatment can be kept constant. Examples of compounds that supply counter cations include MgO, Mg(OH) ₂ , CaO, Ca(OH) ₂ , CaCO ₃ , NH ₃ , NH ₄ OH, NaOH, NaHCO ₃ , and Na ₂ CO _3. The counter cation is preferably a sodium ion or a magnesium ion.
The inorganic salts are usually contained in the lignin derivative in an amount of about 3 to 20%, and can be measured by a known method.

In the sulfurous acid treatment, when a solution of at least one of sulfurous acid and sulfite is used, the solution may contain, in addition to _SO2 , the above-mentioned counter cation (salt) and a digestion and penetration agent (for example, a cyclic ketone compound such as anthraquinone sulfonate, anthraquinone, or tetrahydroanthraquinone), as necessary.

There are no limitations on the equipment used for sulfite treatment; for example, commonly known dissolving pulp manufacturing equipment can be used.

The intermediate product can be separated from the solution of at least one of sulfurous acid and sulfite salts according to a conventional method. For example, the separation method may be a method for separating the sulfurous acid digestion effluent after sulfurous acid digestion.

Next, the intermediate composition is washed and dehydrated to obtain a sulfite-treated product. By washing and dehydrating, components contained in the intermediate composition that cannot be completely removed by the sulfite treatment can be removed.

The washing may be carried out in the same manner as the washing of unbleached sulfite pulp obtained by the sulfite cooking method. The washing may be a single-stage washing or a multi-stage washing. By carrying out multi-stage washing, the washing can be carried out sufficiently. When carrying out multi-stage washing, dehydration may be carried out each time, or may be carried out only for some of the times.
Washing is usually performed using a washing machine. The washing machine used for washing is not particularly limited. For example, a displacement washing type washing machine and a dilution dehydration washing type washing machine can be mentioned.

The dehydration can be carried out under ordinary conditions, for example, in the same manner as in the dehydration of unbleached sulfite pulp after washing obtained in the sulfite cooking method.
Dehydration is usually performed using a dehydrator. The type of dehydrator used for dehydration is not particularly limited. For example, a drum-type squeeze dehydrator, a rotary press, or a continuous squeeze dehydrator may be used.

The sulfite-treated product is then washed and dehydrated, and separated and purified to obtain the desired lignin derivative. Examples of separation and purification include an alkaline oxidation process and an ultrafiltration process.

When alkaline oxidation treatment is performed, the sulfite-treated material is subjected to alkaline oxidation treatment, and then the insoluble matter can be centrifuged and recovered as the supernatant.

The alkaline oxidation treatment can be carried out by placing the sulfurous acid-treated material under alkaline conditions. Placing under alkaline conditions usually means placing the material in an aqueous solution with a pH value of 8 or higher, preferably a pH value of 9 or higher. The upper limit of the pH value is usually 14.

In the alkaline oxidation treatment, an alkaline substance is usually brought into contact with the sulfite treatment product. The alkaline substance is not particularly limited, but examples thereof include calcium hydroxide, magnesium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, and ammonia. Among these, sodium hydroxide is preferred.
The alkaline substances may be used alone or in combination of two or more.

Examples of methods for contacting an alkaline substance with the sulfurous acid-treated product include preparing a dispersion or solution (e.g., an aqueous dispersion or aqueous solution) of the sulfurous acid-treated product and adding the alkaline substance to the dispersion or solution, and adding a solution or dispersion (e.g., an aqueous dispersion or aqueous solution) of the alkaline substance to the sulfurous acid-treated product.

The temperature of the alkaline oxidation treatment is not particularly limited, but is preferably 40°C or higher, and more preferably 60°C or higher. The upper limit is preferably 150°C or lower.

The amount of alkaline substance in the alkaline oxidation treatment is preferably 0.5 to 20% by mass, more preferably 1.0 to 15% by mass, based on the solids mass of the sulfite treated product, or, when preparing an aqueous solution or dispersion by dispersing the alkaline treated extract in an aqueous solvent (e.g., water), based on the mass of the aqueous solution or dispersion.

The time for the alkaline oxidation treatment is not particularly limited, but is preferably 0.1 hours or more, more preferably 0.5 hours or more. The upper limit is preferably 10 hours or less, more preferably 6 hours or less.

Prior to the alkaline oxidation treatment, the sulfite-treated product may be dissolved, dispersed, or its concentration adjusted (preparation of a solution or dispersion in an aqueous solvent such as water) as necessary. Dispersion can be performed by passing the product through a disc refiner, adding it to a mixer or disperser, or by kneading the product. The concentration can be adjusted, for example, by using an aqueous solvent such as water.

The ultrafiltration process can be carried out using an ultrafiltration membrane (hereinafter also referred to as "UF membrane"). As the UF membrane, a known UF membrane can be used. For example, a hollow fiber membrane, a spiral membrane, a tubular membrane, and a flat membrane can be mentioned.
The material of the UF membrane may be any known material, such as cellulose acetate, aromatic polyamide, polyvinyl alcohol, polysulfone, polyvinylidene fluoride, polyethylene, polyacrylonitrile, or ceramic. The UF membrane may be a commercially available product.

The molecular weight cutoff of the UF membrane is preferably 5,000 to 30,000, more preferably 10,000 to 25,000, and even more preferably 15,000 to 23,000. Using a UF membrane with a molecular weight cutoff of 5,000 or more can prevent the separation speed of the black liquor from slowing down excessively. Also, using a UF membrane with a molecular weight cutoff of 30,000 or less can prevent lignin from being unable to be separated from the black liquor.

The concentration ratio by ultrafiltration using a UF membrane can be set as desired. In other words, the ultrafiltration process can be stopped when the amount of concentrated liquid flowing out reaches the desired amount.

The temperature of the black liquor during ultrafiltration is not particularly limited. For example, it is preferably 20 to 80° C., and more preferably 20 to 70° C. in consideration of the heat resistance of the UF membrane material.
The pH value of the black liquor during the ultrafiltration treatment is preferably 2 to 11.
The solids concentration (w/w) of the black liquor during ultrafiltration is preferably 2 to 30%, more preferably 5 to 15%.

[1-3. Other ingredients]
The solid cement dispersant of the present invention may contain optional components other than the above-mentioned components (A) and (B) as long as the effects of the present invention are not impaired.
Examples of optional components include known additives for cement compositions such as water-soluble polymers, hardening accelerators, thickeners, polymer emulsions, air entraining agents, cement wetting agents, expansion agents, waterproofing agents, flocculants, drying shrinkage reducing agents, strength enhancing agents, antifoaming agents, AE agents, surfactants, etc. These may be used alone or in combination of two or more.

An example of a water-soluble polymer is a polyalkylene glycol. More specifically, examples include polyethylene glycol, polypropylene glycol, polyethylene polypropylene glycol, and polyethylene polybutylene glycol. The content of the water-soluble polymer is preferably 0.01 to 50% by weight of component (A).

Examples of hardening accelerators include soluble calcium salts such as calcium chloride, calcium nitrite, and calcium nitrate; chlorides such as iron chloride and magnesium chloride; thiosulfates; formic acid; and formates such as calcium formate. The hardening accelerators may be used alone or in combination of two or more. The content of the hardening accelerator is preferably 0.01 to 50% by weight relative to component (A).

[2. Method for producing solid cement dispersant]
The method for producing a solid cement dispersant of the present invention is a method for producing a solid cement dispersant by drying and solidifying a liquid material containing at least component (A): a copolymer having at least two kinds of constituent units selected from the group consisting of constituent units (I) derived from a monomer represented by general formula (1), constituent units (II) derived from a monomer represented by general formula (2), and constituent units (III) derived from a monomer represented by general formula (3), and component (B): a lignin derivative.
Details of each component are the same as those described in [1. Solid cement dispersant].

Drying methods may be known. Examples include a method of neutralizing the salt with a hydroxide of a divalent metal such as calcium or magnesium to form a polyvalent metal salt and then drying it; a method of supporting the salt on an inorganic powder such as silica-based fine powder and drying it; a method of drying and solidifying the salt into a thin film on a support in a drying device (e.g., a drum-type drying device, a disk-type drying device, or a belt-type drying device); and a method of drying and solidifying the salt using a spray dryer.

[3. Cement Composition]
The cement composition of the present invention contains the solid cement dispersant described in [1. Solid cement dispersant]. More specifically, the cement composition is a cement paste, mortar, concrete, plaster, etc., prepared by adding the solid cement dispersant to a hydraulic material such as cement.

Examples of hydraulic materials include cement, gypsum (hemihydrate, dihydrate, etc.), and dolomite. The most common hydraulic material is cement.

There are no particular limitations on the cement. Examples include Portland cement (normal, early strength, super early strength, moderate heat, sulfate resistant, and low alkali forms of each), various blended cements (blast furnace cement, silica cement, fly ash cement), white Portland cement, alumina cement, super rapid hardening cement (1 clinker rapid hardening cement, 2 clinker rapid hardening cement, magnesium phosphate cement), cement for grouting, oil well cement, low heat cement (low heat type blast furnace cement, low heat type blast furnace cement mixed with fly ash, high belite content cement), ultra high strength cement, cement-based solidification material, ecocement (cement manufactured using one or more of municipal waste incineration ash and sewage sludge incineration ash as raw materials), etc. Cement may contain blast furnace slag, fly ash, cinder ash, clinker ash, husk ash, silica fume, silica powder, limestone powder, and other fine powders, gypsum, etc.

The cement composition may also contain aggregate. The aggregate may be either fine aggregate or coarse aggregate. Examples of aggregate include sand, gravel, crushed stone, granulated slag, recycled aggregate, and refractory aggregates such as silica stone, silica sand powder, clay, zircon, high alumina, silicon carbide, graphite, chrome, chromium-magnesium, and magnesia.

There are no particular limitations on the amount of solid cement dispersant added to a cement composition. For example, when the cement composition is mortar or concrete, the following amounts are added so that the solid cement dispersant is uniformly dispersed in the cement matrix, thickening of fresh concrete is suppressed, and a cement composition with good fluidity can be prepared. The amount added is a ratio to the total weight of the hydraulic material (cement).

The lower limit of the amount of solid cement dispersant added (mixture amount) is preferably 0.001% by weight or more, more preferably 0.01% by weight or more, and even more preferably 0.1% by weight or more. The upper limit is preferably 30% by weight or less, more preferably 25% by weight or less, and even more preferably 20% by weight or less. In other words, 0.001 to 30% by weight is preferable, 0.01 to 25% by weight is more preferable, and 0.1 to 20% by weight is even more preferable.

The above cement composition is useful as concrete, for example, ready-mixed concrete, concrete for secondary concrete products (precast concrete), concrete for centrifugal molding, concrete for vibration compaction, steam cured concrete, lightweight aerated concrete, autoclave lightweight aerated concrete, shotcrete, and the like.
It is also effective as a mortar or concrete that requires high fluidity, such as medium fluidity concrete (concrete with a slump value in the range of 22 to 25 cm), high fluidity concrete (concrete with a slump value of 25 cm or more and a slump flow value in the range of 50 to 70 cm), self-compacting concrete, and self-leveling material.

The present invention will be described in detail below with reference to examples. The following examples are provided to better explain the present invention, and are not intended to limit the present invention. The methods for measuring physical properties and the like are the same as those described above, unless otherwise specified. "Parts" refers to parts by mass.

[Lignosulfonic acid content (wt%) in lignin derivatives]: The lignosulfonic acid content (wt%) was calculated by calculating the amount of methoxyl groups (wt%) present in 10 mg of sample according to the quantitative determination of methoxyl groups by the Viebock and Schwappach method described in Methods in Lignin Chemistry (edited by Nakano Junzo, Uni Publishing Co., Ltd.), and converting this to the lignosulfonic acid content (wt%).

[Content (wt%) of inorganic salts in lignin derivative]: The amount (wt%) of inorganic salts present in 1 g of sample was measured using an inductively coupled plasma optical emission spectrometer (ICP, manufactured by Seiko Electronic Industries Co., Ltd.).

[Content of reducing sugars and/or modified sugars in lignin derivatives (wt %)]: The content of reducing sugars and/or modified sugars was calculated using the following formula (β).

[Solid content (wt%) of solid cement dispersant]: 5 mg of sample was weighed out in a dedicated aluminum cup using an infrared moisture meter (Kett Electric Laboratory Co., Ltd.). After heating this at 105°C using the same device, the solid content was calculated based on the mass loss when the weight change rate was less than 0.05%.

[Mortar flow (mm)]: The mortar flow of the prepared mortar was measured immediately after mixing and t minutes after the start of mixing in accordance with the flow test in "JIS A 1171 (Test method for polymer cement mortar)".

[Retention rate (%)]: Calculated by dividing the mortar flow t minutes after the start of mixing by the mortar flow immediately after mixing and multiplying by 100.

[Solubility (mL/g)]: Calculated from the amount of deionized water (mL) in which 1 g of the solid cement dispersant was completely dissolved. The evaluation criteria for whether or not it was dissolved are as shown in the upper row.

[Evaluation of powder fluidity]: 1 g of the solid cement dispersant was placed on the inner wall of a stainless steel funnel (inner diameter φ10 mm). Then, while applying vibration to the funnel by hand, it was evaluated whether the solid cement dispersant passed through the funnel. The powder fluidity was evaluated based on the passing condition of the solid cement dispersant according to the following criteria.
A: The solid cement dispersant passes through the funnel and has excellent powder fluidity.
B: The solid cement dispersant adheres to the funnel wall, but passes through the funnel, and the powder fluidity is somewhat excellent.
C: The solid cement dispersant does not pass through the funnel, and the powder fluidity is poor.

(Production Example 1: Production of Component (A-1))
A glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen inlet tube and a dropping device was charged with 172 parts of water and 168 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10). The reaction vessel was replaced with nitrogen under stirring, and the temperature was raised to 100°C under a nitrogen atmosphere. Then, a monomer aqueous solution obtained by mixing 38 parts of acrylic acid and 149 parts of water, and a mixed solution of 3 parts of ammonium persulfate and 47 parts of water were continuously dropped into the reaction vessel held at 100°C for 2 hours each. After the dropwise addition, the reaction was further carried out for 1 hour while keeping the temperature at 100°C, and the pH was adjusted to 7 with a 31% aqueous sodium hydroxide solution to obtain an aqueous solution of the copolymer. The copolymer in the liquid was copolymer (A-1) (weight average molecular weight 16,100, Mw/Mn 1.60).

(Production Example 2: Production of Component (A-2))
254 parts of water was charged into a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen inlet tube and a dropping device, and the inside of the reaction vessel was replaced with nitrogen under stirring, and the temperature was raised to 100 ° C. under a nitrogen atmosphere. Thereafter, a monomer aqueous solution obtained by mixing 33 parts of methacrylic acid, 215 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added: 14), 3 parts of 3-mercaptopropionic acid, and 43 parts of water, and a mixed solution of 3 parts of ammonium persulfate and 38 parts of water were continuously dropped into a reaction vessel maintained at 100 ° C. for 2 hours each. After the dropwise addition was completed, the reaction was further carried out for 1 hour while maintaining the temperature at 100 ° C., and the pH was adjusted to 7 with a 31% aqueous sodium hydroxide solution to obtain an aqueous solution of the copolymer. The copolymer in the liquid was copolymer (A-2) (weight average molecular weight 12,100, Mw / Mn 1.40).

(Production Example 3: Production of Component (A-3))
In a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen inlet tube and a dropping device, 180 parts of water, 179 parts of an ethylene oxide adduct of methallyl alcohol (average number of moles of ethylene oxide added: 53), and 0.6 parts of hydrogen peroxide were charged, and the reaction vessel was replaced with nitrogen while stirring. After heating to 40°C under a nitrogen atmosphere, a monomer aqueous solution containing 19 parts of acrylic acid and 76 parts of water, and a mixed solution containing 1 part of L-ascorbic acid, 1 part of 3-mercaptopropionic acid and 22 parts of water were continuously dropped into the reaction vessel held at 40°C for 2 hours each. After the dropping was completed, the reaction was continued for another 1 hour while maintaining the temperature, and an aqueous solution of a copolymer was obtained. The copolymer in the liquid was copolymer (A-3) (weight average molecular weight: 24,000, Mw/Mn: 1.55).

(Production Example 4: Production of Component (A-4))
In a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen inlet tube and a dropping device, 654 parts of water and 17 parts of polyethylene glycol monoallyl ether (average number of moles of ethylene oxide added: 10) were charged, and the reaction vessel was replaced with nitrogen while stirring. After heating to 80°C under a nitrogen atmosphere, a monomer aqueous solution containing 10 parts of methacrylic acid, 0.1 parts of acrylic acid, 49 parts of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide added: 25), 81 parts of 2-hydroxypropyl acrylate, and 144 parts of water, and a mixed solution of 3 parts of ammonium persulfate and 43 parts of water were continuously dropped into a reaction vessel maintained at 80°C for 2 hours each. After the dropwise addition, the temperature was maintained at 100°C and the reaction was continued for another 1 hour to obtain an aqueous solution of a copolymer. The pH of this solution was adjusted to 4 with a 30% aqueous NaOH solution. The copolymer in the liquid was copolymer (A-4) (weight average molecular weight: 22,000, Mw/Mn: 2.10).

(Production Example 5: Production of Component (B-1))
Wood (radiata pine) was digested with magnesium sulfite at 140° C. for 3 hours under the condition of a solution pH of 2, and the resulting sulfite digestion waste liquid was adjusted to pH 5.0. This was subjected to ultrafiltration using a polysulfone-based ultrafiltration membrane with a molecular weight cutoff of 20,000, and the concentrated liquid was used as the lignin derivative (B-1).

(Production Example 6: Production of Component (B-2))
Wood (radiata pine) was digested at 140° C. for 3 hours using magnesium sulfite under the condition of a solution pH of 2, and the resulting sulfite digestion waste liquor was adjusted to pH 5.0 to obtain a lignin derivative (B-2).

(Examples 1, 5, 7 to 9: Production of solid cement dispersants)
A mixture of components (A) and (B) having the formulation shown in Table 1 was dried in a spray dryer to obtain a powder.

(Examples 2 to 4, 6: Production of solid cement dispersants)
A mixture of components (A) and (B) according to the formulation shown in Table 1 was dried in a drum dryer to obtain a powder.

(Comparative Examples 1 to 6: Production of Liquid Cement Dispersants)
The components (A) and (B) shown in Table 1 were mixed together.

(Comparative Examples 7-8: Production of solid cement dispersants)
This is a powdery product obtained by drying the component (B) shown in Table 1 using a spray dryer.

Details of the above solid cement dispersants and liquid cement dispersants are shown in Table 1 below.

Mortar was prepared using the above solid cement dispersants or liquid cement dispersants, and a mortar flow test was conducted. The mortar preparation conditions are as follows:

At ambient temperature (20°C), cement, water, and the solid or liquid cement dispersant shown in Table 2 were added and mechanically mixed with a mortar mixer at low speed for 60 seconds and high speed for 90 seconds to obtain mortars (cement compositions) of the examples and comparative examples. Mortar flow values were measured using these mortars. The test results are shown in Table 3.

Details of the symbols in Table 2 are given below.
C: Equal amounts of the following three types of cement: Ordinary Portland cement (manufactured by Ube Mitsubishi Cement Co., Ltd., specific gravity 3.16)
Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, specific gravity 3.16)
Ordinary Portland cement (Tokuyama Corporation, specific gravity 3.16)
W: Tap water S: Fine aggregate (Kakegawa land sand, density 2.58)

As can be seen from Table 3, the solid cement dispersant of the present invention is more suitable for maintaining dispersion retention and transportability, and has excellent initial dispersibility, compared to liquid cement dispersants of the same composition (see Examples 1 to 6 and Comparative Examples 1 to 6). Even when a lignin derivative with a low content of lignin sulfonic acid is used, it is more suitable for maintaining dispersion retention and transportability, and has excellent initial dispersibility (see Examples 7 to 9).
On the other hand, the lignin derivative alone was inferior in initial dispersibility and dispersion retention compared to the case where the same amount or less of the lignin derivative was contained (see Examples 1 and 8 and Comparative Examples 7 to 8).

(Production Example 7: Production of Component (A-5))
In a glass reaction vessel equipped with a thermometer, a stirrer, a reflux device, a nitrogen inlet tube and a dropping device, 180 parts of water, 179 parts of an ethylene oxide adduct of methallyl alcohol (average number of moles of ethylene oxide added: 53), and 0.6 parts of hydrogen peroxide were charged, and the reaction vessel was replaced with nitrogen while stirring. After heating to 40°C under a nitrogen atmosphere, a monomer aqueous solution containing 19 parts of acrylic acid and 76 parts of water, and a mixed solution containing 1 part of sodium formaldehyde sulfoxylate, 1 part of 3-mercaptopropionic acid, and 22 parts of water were continuously dropped into the reaction vessel held at 40°C for 2 hours each. After the dropping was completed, the reaction was continued for another 1 hour while maintaining the temperature, and an aqueous solution of a copolymer was obtained. The copolymer in the liquid was copolymer (A-5) (weight average molecular weight: 28,000, Mw/Mn: 1.73).

(Production Example 8: Production of Component (B-3))
Wood (radiata pine) was digested at 140° C. for 3 hours using magnesium sulfite under the condition of a solution pH of 2, and the resulting sulfite digestion waste liquor was adjusted to pH 7.0 to obtain a lignin derivative (B-3).

(Examples 10 to 11: Production of solid cement dispersants)
A liquid mixture of components (A) and (B) according to the formulation shown in Table 4 was dried in a spray dryer to form a powder.

(Comparative Examples 9 to 10: Production of Liquid Cement Dispersant)
A liquid mixture of component (A) and component (B) having the formulation shown in Table 4.

(Comparative Examples 11 to 12: Production of solid cement dispersants)
This is a powdery product obtained by drying the component (B) produced in Production Examples 5 and 8 using a spray dryer.

(Comparative Example 13: Production of liquid cement dispersant)
This is the component (A) produced in Production Example 7.

Details of the above solid cement dispersants and liquid cement dispersants are shown in Table 4 below.

Mortar was prepared using the above solid cement dispersants or liquid cement dispersants, and a mortar flow test was conducted. The mortar preparation conditions are as follows:

At ambient temperature (20°C), cement, water, and the solid or liquid cement dispersant shown in Table 6 were added as shown in Table 5, and mechanically mixed with a mortar mixer at low speed for 60 seconds and high speed for 90 seconds to obtain mortars (cement compositions) of the examples and comparative examples. Mortar flow values were measured using these mortars. The test results are shown in Table 6.

Details of the symbols in Table 5 are given below.
C: Equal amounts of the following three types of cement: Ordinary Portland cement (manufactured by Ube Mitsubishi Cement Co., Ltd., specific gravity 3.16)
Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation, specific gravity 3.16)
Ordinary Portland cement (Tokuyama Corporation, specific gravity 3.16)
W: Tap water S: Fine aggregate (Kakegawa land sand, density 2.58)

As can be seen from Table 6, by making the cement dispersant of the present invention into a solid form, it is possible to maintain dispersion retention (see Examples 10 and 11 and Comparative Examples 9 and 10). Even if only component (B) is in a solid form, the dispersibility immediately after kneading is low. Therefore, even if it appears that the dispersion retention can be maintained after 60 minutes, it is found that there is no dispersion retention at all, since the mortar flow value is 100 mm (see Comparative Examples 11 and 12). Furthermore, even if component (A) is used as it is in a liquid form, it is found that the dispersion retention is poor, even if the initial dispersibility is high (see Comparative Example 13).
Therefore, it is clear that in order to maintain the dispersion retention, it is preferable that components (A) and (B) are in solid form.

Claims (8)

Component (A): A copolymer having at least two kinds of constituent units selected from the group consisting of a constituent unit (I) derived from a monomer represented by the following general formula (1), a constituent unit (II) derived from a monomer represented by the following general formula (2), and a constituent unit (III) derived from a monomer represented by the following general formula (3), and Component (B): A lignin derivative containing lignosulfonic acid or a salt thereof, reducing sugars and/or sugar-modified products, and inorganic salts, which is obtained by subjecting a lignocellulose raw material to a sulfite treatment and then subjecting the resulting material to ultrafiltration treatment using an ultrafiltration membrane having a molecular weight cutoff of 5,000 to 30,000 ,
The moisture content is 10% by weight or less.
Solid cement dispersant.

(In the general formula (1), R ¹ to R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. p represents an integer of 0 to 2. q represents an integer of 0 to 1. ^{A 1} O may be the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300. R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

(In the general formula (2), R ⁵ to R ⁷ each independently represent a hydrogen atom, a methyl group, or a -(CH ₂ ) _r COOM ² group. However, when a -(CH ₂ ) _r COOM ² group is represented, it may form an anhydride group with a -COOM ¹ group or another -(CH ₂ ) _r COOM ² group. When an anhydride group is formed, M ¹ or M ² of the group does not exist. M ¹ to M ² each independently represent a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.)

(In the general formula (3), R ⁸ to R ¹⁰ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹¹ represents a hydrocarbon group having 1 to 4 carbon atoms which may contain a heteroatom. s represents an integer of 0 to 2.) The solid cement dispersant according to claim 1, wherein the content of component (B) is 40% by weight or more. A solid cement dispersant as described in claim 1 or 2, wherein the content of component (A) is 1 to 70% by weight. A solid cement dispersant according to any one of claims 1 to 3, wherein the component (B) has a lignin sulfonic acid or salt thereof content of 50% by weight or more. The solid cement dispersant according to any one of claims 1 to 4, wherein the solubility represented by the following mathematical formula (α) is less than 6.0.

(In the above formula (α), Da is the amount of water (mL) required to dissolve the solid cement dispersant. Db is the dry mass (g) of the dissolved solid cement dispersant.) The solubility represented by the following formula (α) is 6.0 or more,
The solid cement dispersant according to any one of claims 1 to 4, wherein the structural unit (I) is a structural unit derived from a monomer represented by the following general formula (1-1):

(In the above formula (α), Da is the amount of water (mL) required to dissolve the solid cement dispersant. Db is the dry mass (g) of the dissolved solid cement dispersant.)

(In the general formula (1-1), EO may be the same or different and represents an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300.) A step of polymerizing at least two types of monomers selected from the group consisting of a monomer represented by the following general formula (1) , a monomer represented by the following general formula (2) , and a monomer represented by the following general formula (3) to prepare a copolymer (component (A)) having at least two types of structural units selected from the group consisting of a structural unit (I) derived from a monomer represented by the following general formula (1), a structural unit (II) derived from a monomer represented by the following general formula (2), and a structural unit (III) derived from a monomer represented by the following general formula ( 3):
a step of subjecting a lignocellulose raw material to a sulfite treatment and then subjecting the resultant to an ultrafiltration treatment using an ultrafiltration membrane having a molecular weight cutoff of 5,000 to 30,000 to prepare a lignin derivative (component (B)) containing lignosulfonic acid or a salt thereof, reducing sugars and/or sugar-modified products, and inorganic salts;
A method for producing a solid cement dispersant, comprising the steps of preparing a liquid containing at least the components (A) and (B) prepared in the above steps, and drying and solidifying the liquid to produce a solid cement dispersant having a water content of 10% by weight or less.

(In the general formula (1), R ¹ to R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. p represents an integer of 0 to 2. q represents an integer of 0 to 1. ^{A 1} O may be the same or different and represent an oxyalkylene group having 2 to 18 carbon atoms. n represents an integer of 1 to 300. R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

(In the general formula (2), R ⁵ to R ⁷ each independently represent a hydrogen atom, a methyl group, or a -(CH ₂ ) _r COOM ² group. However, when a -(CH ₂ ) _r COOM ² group is represented, it may form an anhydride group with a -COOM ¹ group or another -(CH ₂ ) _r COOM ² group. When an anhydride group is formed, M ¹ or M ² of the group does not exist. M ¹ to M ² each independently represent a hydrogen atom, an alkali metal, an alkaline earth metal, an ammonium group, an alkylammonium group, or a substituted alkylammonium group. r represents an integer of 0 to 2.)

(In the general formula (3), R ⁸ to R ¹⁰ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹¹ represents a hydrocarbon group having 1 to 4 carbon atoms which may contain a heteroatom. s represents an integer of 0 to 2.) A cement composition containing the solid cement dispersant according to any one of claims 1 to 6.