JP7135394B2 - Crosslinked polymer flocculant and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a crosslinked polymer flocculant and a method for producing the same. More specifically, it relates to a crosslinked polymer flocculant having a water-containing substance that satisfies predetermined viscoelasticity in an aqueous solution, and a method for producing the same.

In recent years, in the case of the use of water-soluble polymers as polymer flocculants, there has been an increasing need for faster dewatering treatment due to the increase in the amount of sludge generated in the dewatering of organic sludge. A polymeric flocculant is desired. In addition, due to the soaring cost of incineration when incinerating dehydrated cake and the shortage of landfill sites when dehydrated cake is disposed of as it is, a polymer flocculant that can reduce the moisture content in the dehydrated cake. is desired. As a polymer flocculant exhibiting such flocculating properties, a branched or crosslinked polymer has been proposed by controlling the structure of the polymer.

For example, Patent Document 1 proposes the use of a crosslinked water-soluble polymer whose aqueous solution has a predetermined viscoelasticity as a polymer flocculant. Patent Document 2 proposes the use of a branched or crosslinked water-soluble polymer using crosslinkable monomers with different polymerizability as a polymer flocculant.

JP 2017-100111 A WO2017/209105

However, the polymer flocculant described in Patent Literature 1 is mainly produced by inverse emulsion polymerization, and thus is costly. In addition, it is a polymer that simply uses a cross-linking agent, and it is easy to obtain a water-insoluble swollen gel with a three-dimensional network structure. It is difficult. Although the polymer flocculant described in Patent Document 2 is a polymer with a high branching effect and a small amount of insoluble matter, it is insufficient for applications requiring a certain amount of insoluble matter.

Ｒ₁、Ｒ₂：それぞれ独立に炭素－炭素不飽和結合をもたない炭素、酸素、窒素および水素から選ばれる群からなる原子で構成される直鎖若しくは分岐を有する鎖状の官能基である。
Ｗ：１５族の非金属元素である。
Ｘ、Ｙ：それぞれ炭素、酸素、窒素および水素から選ばれる群からなる原子で構成される直鎖若しくは分岐を有する鎖状の官能基であって、かつそれぞれ炭素－炭素不飽和結合を少なくとも１つ持つ。ただし、ＸとＹは異なる構造を有する。
Ｚ：塩素イオン、臭素イオンまたはヨウ素イオンである。
［３］ 前記架橋性単量体（ａ）成分の濃度が、０．００３５～０．０２５質量％である、前記［１］または［２］に記載の架橋型高分子凝集剤。
［４］ 前記架橋型高分子凝集剤の０．５質量％水溶液５００ｇ中の不溶解分量が、前記架橋型高分子凝集剤の０．５質量％水溶液５００ｇに対して６０ｇ以上４００ｇ以下である、前記［１］～［３］のいずれかに記載の架橋型高分子凝集剤。
［５］ 分子内に重合性不飽和結合を１つ有する水溶性不飽和単量体（ｂ）由来成分を、一種類もしくは二種類以上をさらに含む、前記［１］～［４］のいずれかに記載の架橋型高分子凝集剤。
［６］ 前記架橋性単量体（ａ）が、下記式（ＩＩ）で表される構造を有する、前記［２］に記載の架橋型高分子凝集剤。

Ｒ₁、Ｒ₂：それぞれ独立にＣＨ₃またはＣ₂Ｈ₅である。
Ｘ、Ｙ：下記式で表されるものである。

Ｒ₃： ＨまたはＣＨ₃
Ｒ₄： ＯまたはＮＨ
Ｒ₅： ＣｎＨ_2n（ｎ＝１～６）
Ｒ₆： 水素原子、メチル基または炭素数１～６の直鎖、分岐状若しくは環状構造を有するアルキルエステル基である。
Ｚ：塩素イオン、臭素イオンまたは表されるヨウ素イオンである。
［７］ 分子内に下記式（Ｉ）由来の構造を有する架橋性単量体（ａ）成分を含む、架橋型高分子凝集剤成分を水に溶解して均一系で重合を行う、架橋型高分子凝集剤の製造方法。

Ｒ₁、Ｒ₂：それぞれ独立に炭素－炭素不飽和結合をもたない炭素、酸素、窒素および水素から選ばれる群からなる原子で構成される直鎖若しくは分岐を有する鎖状の官能基である。
Ｗ：１５族の非金属元素である。
Ｘ、Ｙ：それぞれ炭素、酸素、窒素および水素から選ばれる群からなる原子で構成される直鎖若しくは分岐を有する鎖状の官能基であって、かつそれぞれ炭素－炭素不飽和結合を少なくとも１つ持つ。ただし、ＸとＹは異なる構造を有する。
Ｚ：塩素イオン、臭素イオンまたはヨウ素イオンである。
［８］ さらに、水溶性不飽和単量体（ｂ）を水に溶解して均一系で重合を行う、［７］に記載の架橋型高分子凝集剤の製造方法。 The inventor of the present invention made the following conclusions as a result of intensive studies in view of the above-mentioned circumstances. That is, the present invention is a crosslinked polymer flocculant having a hydrous substance that satisfies a specific elastic modulus in an aqueous solution, and a method for producing the same.
[1] A crosslinked polymer flocculant having a gel-like water-containing substance,
Storage elasticity when measured by strain rate dependence measurement at 25 ° C. using a rheometer for the gel-like water-containing material that is an insoluble portion of a 0.5% by mass aqueous solution of the cross-linked polymer flocculant A crosslinked polymer flocculant in which the maximum value of the rate G1 (Pas) satisfies the following formula (1).
3<G1<800 Expression (1)
[2] The crosslinkable polymer flocculant according to [1] above, which contains a crosslinkable monomer (a) component having a structure derived from the following formula (I) in the molecule.

R ₁ , R ₂ : Linear or branched functional groups each independently composed of atoms selected from the group consisting of carbon, oxygen, nitrogen and hydrogen which do not have a carbon-carbon unsaturated bond. .
W: A group 15 non-metallic element.
X, Y: each a linear or branched chain functional group composed of atoms selected from the group selected from carbon, oxygen, nitrogen and hydrogen, and each having at least one carbon-carbon unsaturated bond have However, X and Y have different structures.
Z: chlorine ion, bromide ion or iodine ion.
[3] The crosslinkable polymer flocculant according to [1] or [2], wherein the crosslinkable monomer (a) component has a concentration of 0.0035 to 0.025% by mass.
[4] The amount of insoluble matter in 500 g of a 0.5% by mass aqueous solution of the crosslinkable polymer flocculant is 60 g or more and 400g or less with respect to 500g of the 0.5% by mass aqueous solution of the crosslinked polymer flocculant. The crosslinked polymer flocculant according to any one of [1] to [3].
[5] Any of the above [1] to [4], further comprising one or more water-soluble unsaturated monomer (b)-derived components having one polymerizable unsaturated bond in the molecule. The crosslinked polymer flocculant according to .
[6] The crosslinkable polymer flocculant according to [2] above, wherein the crosslinkable monomer (a) has a structure represented by the following formula (II).

R ₁ , R ₂ : each independently CH ₃ or C ₂ H ₅ ;
X, Y: Those represented by the following formulas.

_R3 : H or _CH3
R4 : O or NH
R ₅ : CnH _2n (n=1-6)
R ₆ : A hydrogen atom, a methyl group, or an alkyl ester group having a linear, branched or cyclic structure with 1 to 6 carbon atoms.
Z: chloride ion, bromide ion or iodine ion as indicated.
[7] A cross-linking type in which a cross-linkable polymer flocculant component containing a cross-linkable monomer (a) component having a structure derived from the following formula (I) in the molecule is dissolved in water and polymerized in a homogeneous system. A method for producing a polymer flocculant.

R ₁ , R ₂ : Linear or branched functional groups each independently composed of atoms selected from the group consisting of carbon, oxygen, nitrogen and hydrogen which do not have a carbon-carbon unsaturated bond. .
W: A group 15 non-metallic element.
X, Y: each a linear or branched chain functional group composed of atoms selected from the group selected from carbon, oxygen, nitrogen and hydrogen, and each having at least one carbon-carbon unsaturated bond have However, X and Y have different structures.
Z: chlorine ion, bromide ion or iodine ion.
[8] The method for producing a crosslinked polymer flocculant according to [7], further comprising dissolving the water-soluble unsaturated monomer (b) in water and conducting homogenous polymerization.

When a crosslinked polymer flocculant having a water content that satisfies a specific elastic modulus in an aqueous solution, such as that of the present invention, is used, high strength and coarse flocs are formed. Furthermore, even in a uniform aqueous solution system, a water-soluble or water-dispersible polymer having a branched or crosslinked structure can be obtained, which is suitable for inexpensive production.

The details of the invention are described below.
The polymer flocculant of the present invention is a crosslinked polymer flocculant and has a gel-like water-containing substance that satisfies the following conditions.
(conditions)
Storage elastic modulus when measured by strain rate dependence measurement at 25 ° C. using a rheometer for a gel-like water-containing material that is an insoluble content of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant The maximum value of G1 (Pas) is a crosslinked polymer flocculant that satisfies the following formula (1).
3<G1<800 Expression (1)

If the maximum value of the storage elastic modulus G1 of the gel-like hydrous material is 3 Pas or less, the crosslinking of the crosslinked polymer is insufficient, and its properties approach those of a linear polymer. As a result, phenomena such as failure to form coarse flocs and failure to improve the filtration rate occur. Further, when the maximum value of the storage elastic modulus G1 is 800 Pas or more, the degree of cross-linking of the cross-linking polymer becomes too high, and a phenomenon such as failure to form coarse flocs occurs.
The maximum value of the storage elastic modulus G1 is preferably 5 Pas or more and 780 Pas or less, more preferably 10 Pas or more and 750 Pas or less, and 15 Pas or more, from the viewpoint of aggregation performance (high floc strength, coarsening of flocs, and low water content of dehydrated cake). 750 Pas or less is particularly preferred.

The method for obtaining the hydrous material is not particularly limited, but for example, passing the aqueous solution of the cross-linking polymer flocculant in the present invention through a predetermined sieve and removing the hydrous material remaining on the sieve. method.

The crosslinkable polymer flocculant of the present invention is preferably a crosslinkable polymer flocculant containing a crosslinkable monomer (a) component having a structure derived from the following formula (I) in its molecule.

Ｒ₁、Ｒ₂：それぞれ独立に炭素－炭素不飽和結合をもたない炭素、酸素、窒素および水素から選ばれる群からなる原子で構成される直鎖若しくは分岐を有する鎖状の官能基である。
Ｗ：１５族の非金属元素である。
Ｘ、Ｙ：それぞれ炭素、酸素、窒素および水素から選ばれる群からなる原子で構成される直鎖若しくは分岐を有する鎖状の官能基であって、かつそれぞれ炭素－炭素不飽和結合を少なくとも１つ持つ。ただし、ＸとＹは異なる構造を有する。
Ｚ：塩素イオン、臭素イオンまたはヨウ素イオンである。

R ₁ , R ₂ : Linear or branched functional groups each independently composed of atoms selected from the group consisting of carbon, oxygen, nitrogen and hydrogen which do not have a carbon-carbon unsaturated bond. .
W: A group 15 non-metallic element.
X, Y: each a linear or branched chain functional group composed of atoms selected from the group selected from carbon, oxygen, nitrogen and hydrogen, and each having at least one carbon-carbon unsaturated bond have However, X and Y have different structures.
Z: chlorine ion, bromide ion or iodine ion.

Chain functional groups having no carbon-carbon unsaturated bond include methyl group, ethyl group, propyl group, i-propyl group, n-butyl group, i-butyl group, carbonyl group and the like.
W is a Group 15 non-metallic element, including nitrogen, phosphorus, arsenic, antimony, and bismuth.
A chain-like functional group having at least one carbon-carbon unsaturated bond includes a (meth)acryloyl group, a crotonoyl group, a vinyl ether group, and the like.

By having a structure derived from formula (I) in the molecule, there is a difference in reactivity between elongation of the main chain and branched cross-linking, making it extremely easy to control the structure. Moreover, a water-soluble polymer can be easily produced.

The crosslinkable polymer flocculant in the present invention preferably contains a crosslinkable monomer (a) having a structure derived from formula (II) below.

Ｒ₁、Ｒ₂は、それぞれ独立にＣＨ₃またはＣ₂Ｈ₅であり、Ｘ、Ｙは、下記式で表されるものである。

R ₁ and R ₂ are each independently CH ₃ or C ₂ H ₅ , and X and Y are represented by the following formulae.

ここで、Ｒ₃は、水素原子又はメチル基であり、Ｒ₄はＯまたはＮＨであり、Ｒ₅はＣｎＨ₂ｎ（ｎ＝１～６）である。
例えば、ＸのＲ₃が水素原子、Ｒ₄がＯである（メタ）アクリル基や、ＸのＲ₃が水素原子、Ｒ₄がＮＨである（メタ）アクリルアミド基を有する構造であることが好ましい。
（メタ）アクリル基や（メタ）アクリルアミド基を有する構造であると、共重合性に優れる。

Here, R ₃ is a hydrogen atom or a methyl group, R ₄ is O or NH, and R ₅ is CnH ₂ n (n=1-6).
For example, a structure having a (meth)acryl group in which R ₃ of X is a hydrogen atom and R ₄ is O, or a (meth)acrylamide group in which R ₃ of X is a hydrogen atom and R ₄ is NH is preferable. .
A structure having a (meth)acryl group or a (meth)acrylamide group is excellent in copolymerizability.

ここで、Ｒ₆は、水素原子、メチル基または炭素数１～６の直鎖、分岐状若しくは環状構造を有するアルキルエステル基である。

Here, R ₆ is a hydrogen atom, a methyl group, or an alkylester group having a linear, branched or cyclic structure having 1 to 6 carbon atoms.

By containing the crosslinkable monomer (a) having a structure derived from formula (II), it becomes extremely easy to control the structure of the crosslinked polymer, and as a result, even in a uniform aqueous solution system, the desired storage elastic modulus is satisfied. A crosslinked polymer flocculant containing water can be easily obtained.

In the present invention, the structure of the crosslinkable monomer (a) derived from formula (II) is preferably the following formula (III).

ここで、Ｒ₁₀及びＲ₁₁は、それぞれ独立して炭素数１～６の直鎖又は分岐のあるアルキル基であり、Ｒ₇は、水素原子又はメチル基であり、Ｒ₈はＯまたはＮＨであり、Ｒ₉はＣｎＨ₂ｎ（ｎ＝１～６）であり、Ｒ₁₂は、水素原子、メチル基または炭素数１～６の直鎖、分岐状若しくは環状構造を有するアルキルエステル基である。

Here, R ₁₀ and R ₁₁ are each independently a linear or branched alkyl group having 1 to 6 carbon atoms, R ₇ is a hydrogen atom or a methyl group, and R ₈ is O or NH. and R ₉ is CnH ₂ n (n=1-6), and R ₁₂ is a hydrogen atom, a methyl group or an alkyl ester group having a linear, branched or cyclic structure having 1-6 carbon atoms.

When the structure derived from formula (II) is formula (III), the difference in reactivity appears remarkably, and the degree of branching/crosslinking can be easily controlled.

Examples of the crosslinkable monomer (a) in the present invention include monomers represented by the following formulas (III-1) to (III-12). These may be used alone or in combination of two or more.

The concentration of the crosslinkable monomer component of the present invention is preferably 0.0035 to 0.025% by mass, more preferably 0.0040 to 0.020% by mass, and more preferably 0.0045 to 0.0045% by mass. 015% by mass is more preferable.
When the concentration is 0.0035% by mass or more, the crosslinking of the crosslinkable polymer is sufficient, and when it is 0.0025% by mass or less, the degree of crosslinking of the crosslinkable polymer does not become too high.

The amount of insoluble matter in 500 g of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant of the present invention is 60 g or more and 400 g or less with respect to 500 g of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant. It is preferably 70 g or more and 350 g or less, and even more preferably 80 g or more and 300 g or less.
The amount of insoluble matter in 500 g of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant is 60 g or more with respect to 500 g of the 0.5% by mass aqueous solution of the crosslinked polymer flocculant. When the cross-linking is sufficient and the weight is 400 g or less, the balance between the insoluble matter and the soluble matter is good.

In the method for producing a crosslinkable polymer flocculant of the present invention, the crosslinkable monomer (a) and a water-soluble unsaturated monomer (b) having one polymerizable unsaturated bond in the molecule are added to water. This is a method for producing a crosslinked polymer flocculant in which the solution is dissolved and polymerized in a homogeneous system.

The method for producing the crosslinkable monomer (a) in the present invention is not particularly limited, and examples thereof include the following methods.
First, a solution (A) in which a tertiary amine having a polymerizable unsaturated bond is dissolved in an organic solvent and a solution (B) in which a halide having a polymerizable unsaturated bond is dissolved in an organic solvent are prepared. Next, while the solution (A) is being stirred in the beaker, the solution (B) is dropped into the beaker using a dropping funnel, and the stirring is continued. At that time, the stirring time and the temperature of the beaker during dropping may be set arbitrarily.

The amount of the crosslinkable monomer (a) to be added is water-soluble insoluble in terms of cohesion performance (high floc strength, coarsening of flocs, and low water content of dehydrated cake) and solubility in water of the resulting polymer. With respect to 100% by mass of the saturated monomer (b), 0.001% by mass or more and 1.0% by mass or less is preferable, 0.003% by mass or more and 0.7% by mass or less is more preferable, and 0.005% by mass % or more and 0.5 mass % or less is particularly preferable.

The crosslinked polymer flocculant in the present invention desirably contains one or more water-soluble unsaturated monomers (b) having one polymerizable unsaturated bond in the molecule. The water-soluble unsaturated monomer (b) means an unsaturated monomer having a solubility of 5 g or more in 100 g of water (20° C.), and includes the following.

Examples of water-soluble unsaturated monomers (b) include the following.
(b1) Nonionic Monomer The following (b1-1) to (b1-3) and mixtures thereof are exemplified.
(b1-1) hydroxyl group- or nitrile group-containing (meth) acrylates, for example, hydroxyl group-containing compounds having 5 to 25 carbon atoms [specifically, (hydroxyethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, polyethylene glycol mono ( meth)acrylate, polyglycerol mono(meth)acrylate, etc.], or nitrile group-containing compounds [2-cyanoethyl(meth)acrylate, etc.].

(b1-2) (meth)acrylamide compounds such as (meth)acrylamide, N-alkyl(meth)acrylamide, N-methyl-, ethyl- and isopropyl(meth)acrylamide, N,N'-dimethyl-, diethyl- and diisopropyl(meth)acrylamide] and N-alkylol, (meth)acrylamide [N-methylol(meth)acrylamide, N,N′-dimethylol(meth)acrylamide, etc.].

(b1-3) Nitrogen atom-containing vinyl monomers other than (b1-1) and (b1-2), such as acrylonitrile, N-vinylformamide, N-vinyl-2-pyrrolidone, vinylimidazole, N-vinylsuccinimide and N- vinylcarbazole and the like.

(b2) Cationic monomer The following (b2-1) to (b2-5) and salts thereof can be exemplified. These salts include, for example, inorganic acid (hydrochloric, sulfuric, phosphoric and nitric acid, etc.) salts, quaternary ammonium salts (such as methyl chloride, dimethyl sulfate and benzyl chloride salts, and mixtures thereof). be done.

(b2-1) tertiary amino group-containing (meth)acrylates such as N,N-dialkylaminoalkyl (meth)acrylates [specifically, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethyl N-morpholinoalkyl (meth)acrylates such as aminopropyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate and N,N-diethylaminopropyl (meth)acrylate, and N-morpholinoethyl (meth)acrylate. mentioned.

(b2-2) Tertiary amino group-containing (meth)acrylamide compound For example, N,N-dialkylaminoalkyl (meth)acrylamide [specifically, N,N-dimethylaminoethyl (meth)acrylamide, N,N- Dimethylaminopropyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide and N,N-diethylaminopropyl (meth)acrylamide, and N-morpholinoethyl (N-morpholinoalkyl (meth)acrylamide such as (meth)acrylamide Acrylamide can be mentioned.

(b2-3) Vinyl Compounds Having Primary or Secondary Amino Group Examples thereof include vinyl compounds having an amino group having 3 to 12 carbon atoms, such as vinylaniline, allylamine, and N-methylvinylamine.

(b2-4) compounds having an amine imide group, such as 1,1,1-trimethylamine (meth)acrylimide, 1,1-dimethyl-1-ethylamine (meth)acrylimide, 1,1-dimethyl-1-(2) '-Phenyl-2'-hydroxyethyl)amine (meth)acrylimide and 1,1,1-trimethylamine (meth)acrylimide.

(b2-5) Nitrogen atom-containing vinyl compounds other than (b2-1) to (b2-4) Examples include 2-vinylpyridine, 3-vinylpiperidine, vinylpyrazine and vinylmorpholine.

(b3) anionic monomers Examples include salts of alkali metals (lithium, sodium, potassium, etc.) or alkaline earth metals (magnesium, calcium, etc.), ammonium salts, amines having 1 to 20 carbon atoms, and mixtures thereof. be done.

(b3-1) unsaturated carboxylic acid (including anhydride)
Examples thereof include monocarboxylic acids such as (meth)acrylic acid, vinylbenzoic acid and allylacetic acid, and dicarboxylic acids such as di(anhydride) maleic acid, fumaric acid and itaconic acid.

(b3-2) Unsaturated sulfonic acid, for example, unsaturated hydrocarbon having a sulfonic acid group such as vinylsulfonic acid and styrenesulfonic acid, 2-(meth)acryloyloxyethanesulfonic acid, 2-(meth)acryloyloxypropanesulfone acid, 3-(meth)acryloyloxypropanesulfonic acid, 2-(meth)acryloyloxybutanesulfonic acid, 4-(meth)acryloyloxybutanesulfonic acid, 2-(meth)acryloyloxy-2,2-dimethylethanesulfone acids, or (meth)acrylates having a sulfonic acid group such as p-(meth)acryloyloxymethylbenzenesulfonic acid; 2-(meth)acryloylaminoethanesulfonic acid, 2-(meth)acryloylaminopropanesulfonic acid, 3 -(meth)acryloylaminopropanesulfonic acid, 2-(meth)acryloylaminobutanesulfonic acid, 4-(meth)acryloylaminobutanesulfonic acid, 2-(meth)acryloylamino-2,2-dimethylethanesulfonic acid and p (meth)acrylamides having a sulfonic acid group such as -(meth)acryloylaminomethylbenzenesulfonic acid, and (meth)allyl sulfosuccinate esters having 5 to 20 carbon atoms.

Of the above (b), preferred are (b1-1), (b2-1), (b2-2), (b3-1) and (b3-2) from the viewpoint of achieving a higher molecular weight Sulfonic acid group-containing (meth)acrylates and sulfonic acid group-containing (meth)acrylamides, most preferably (b1-2) (meth)acrylamide, (b1-3) acrylonitrile, N-vinyl Formamide, N,N-dimethylaminoethyl (meth)acrylate and salts thereof in (b2-1), (meth)acrylic acid, (anhydride) maleic acid, itaconic acid and these in (b3-1) alkali metal (lithium, sodium, potassium, etc.) salts, 2-(meth)acryloyloxyethanesulfonic acid, 2-(meth)acryloyloxypropanesulfonic acid, 3-(meth)acryloyloxy in (b3-2) propanesulfonic acid, 2-(meth)acryloylamino-2,2-dimethylethanesulfonic acid and alkali metal salts thereof.
Moreover, these (b) may be polymerized alone or optionally copolymerized.

If necessary, the above (b) may be used in combination with another monomer (x). In that case, the ratio (mol %) of (x) is It is usually 0 or more, preferably 0.1 or more, more preferably 0.5 or more, and usually 40 or less, preferably 20 or less, more preferably 10 or less.
Other monomers here mean monomers having a solubility of less than 5 g in 100 g of water (20° C.).

Other monomers (x) include, for example, the following.
(x1) to (x5) below, and mixtures thereof (x1) C4-23 (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, octadecyl (meth)acrylate and epoxy group-containing (meth)acrylates having 6 to 20 carbon atoms such as cyclohexyl (meth)acrylate and glycidyl (meth)acrylate.

(x2) Polypropylene glycol For example, adducts of unsaturated carboxylic acid monoester monools or diols with propylene oxide (hereinafter abbreviated as PO) can be mentioned. Specifically, (meth)acrylic acid esters obtained by adding monools (ethanol, propanol, butanol, etc.) to PO [ω-methoxypropylene oxide, ethoxypropylene oxide, propoxypropylene oxide, butoxypropylene oxide and cyclohexoxypropylene oxide and phenoxypolypropylene glycol (meth)acrylate] and the like.

(x3) Unsaturated hydrocarbon Examples include unsaturated hydrocarbons having 2 to 30 carbon atoms such as ethylene, nonene, styrene, and 1-methylstyrene.

(x4) Unsaturated alcohol Examples include unsaturated alcohols having 3 to 20 carbon atoms such as vinyl alcohol and (meth)allyl alcohol, and esters derived from these alcohols such as vinyl acetate.

(x5) Halogen-containing compounds Examples include vinyl chloride and vinyl bromide.

The method of polymerization in the present invention is not particularly limited, and examples thereof include bulk polymerization, aqueous solution polymerization, precipitation polymerization, suspension polymerization, emulsion polymerization, and microemulsion polymerization. Among these, polymerization in an aqueous solution system is preferable from the viewpoint that it can be produced most easily and at a low cost.

In the polymerization method of the present invention, first, the crosslinkable monomer (a) is dissolved in water, and if desired, the water-soluble unsaturated monomer (b) is also dissolved in water. Next, after adding a polymerization initiator and, if necessary, a chain transfer agent, etc., nitrogen gas is blown in to obtain a reactive monomer solution. For this reactive monomer solution, if the added polymerization initiator is a thermal polymerization initiator, thermal polymerization is performed using a water bath. Polymerization is carried out.

By carrying out the polymerization method of the present invention, a crosslinked polymer flocculant can be produced easily and inexpensively.

In addition, polymerization using ordinary radical initiators can be used, and examples of radical initiators include general azo initiators, peroxide initiators, photopolymerization initiators using photosensitizers, and redox initiators. be done. An azo initiator, a peroxide initiator, a photopolymerization initiator using a photosensitizer, a redox initiator, etc. may be used alone or in combination.

Examples of azo initiators and peroxide initiators include 1,1′-azobis(cyclohexane-1-carbonitrile), 2,2′-azobis(2,4,4-trimethylpentene), 2- Cyano-2-propyrazoformamide, dicumyl peroxide, t-butyl cumyl peroxide, di-t-butyl peroxide, t-butylperoxy-3,3,5-trimethylhexanoate, t-butylperoxy Laurate, t-butyl peroxyacetate, di-t-butyl peroxyhexahydroterephthalate, di-t-butyl peroxyazelate, t-butyl peroxyallyl carbonate, t-butyl peroxy isopropyl carbonate, 1,1 -di-t-butylperoxycyclohexane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-hexylperoxy-3,3,5-trimethyl Cyclohexane, 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2 , 2'-azobis(2-methylbutyronitrile), acetylcyclohexylsulfonyl peroxide, isobutyryl peroxide, cumyl peroxyneodecanoate, di-isopropyl peroxycarbonate, di-allyl peroxydicarbonate, di- n-propyl peroxydicarbonate, di-myristyl peroxydicarbonate, cumyl peroxyneohexanoate, di(2-ethoxyethyl) peroxydicarbonate, di(methoxyisopropyl) peroxydicarbonate, di(2- ethylhexyl)peroxydicarbonate, t-hexylperoxyneodecanate, di(3-methyl-3-methoxybutyl)peroxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxyneohexano ate, t-butyl peroxyneohexanoate, 2,4-dichlorobenzoyl peroxide, t-hexyl peroxypivalate, t-butyl peroxypivalate, 3,5,5-trimethylhexanoyl peroxide, octa noyl peroxide, decanoyl peroxide, lauroyl peroxide, cumyl peroxyoctoate, acetyl peroxide and the like. These can also be used together.

Examples of photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl, benzophenone, p-methoxybenzophenone, 2,2-diethoxyacetophenone, α,α-dimethoxy- carbonyl compounds such as α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis(dimethylamino)benzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide and benzoyldiethoxyphosphine oxide; These can also be used together.

Redox initiators include, for example, hydrogen peroxide/ferrous salt, persulfate/sodium sulfite, cumene hydroperoxide/ferrous salt, benzoyl peroxide/dimethylaniline, peroxide (hydrogen peroxide , hydroperoxide, etc.)/organometallic alkyls (triethylammonium, triethylboron, diethylzinc, etc.), oxygen/organometallic alkyls and the like.

The amount of the polymerization initiator to be added is, from the viewpoint of obtaining the optimum molecular weight as the flocculant, paper strength agent, etc. of the present invention, the crosslinkable monomer (a), the water-soluble unsaturated monomer (b), and if necessary Based on the total weight of other monomers (x), it is preferably 0.0001% by mass or more and 0.05% by mass or less, more preferably 0.0005% by mass or more and 0.02% by mass or less, and 0.001% by mass or more and 0 0.01% by mass or less is particularly preferred.

A chain transfer agent may also be used if necessary. The chain transfer agent is not particularly limited, and examples include organic acids [4-pentenoic acid, 5-hexenoic acid, 6-heptenoic acid, 7-octenoic acid, 8-nonenoic acid, 9-decenoic acid, 10-undecenoic acid, 11-dodecenoic acid, p-vinylbenzoic acid, p-allylbenzoic acid, 3-vinylphenylacetic acid, 4-vinylphenylacetic acid, 4-allylphenylacetic acid], inorganic acids [sulfuric acid, sulfurous acid, Nitric acid, nitrous acid, phosphoric acid, phosphorous acid, diphosphorous acid, phosphonic acid], compounds having one or more hydroxyl groups in the molecule [e.g., methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol , polyethylene glycol and polyoxyethylene-polyoxypropylene copolymers], compounds having one or more amino groups in the molecule [e.g., ammonia, amines (e.g., methylamine, dimethylamine, triethylamine and propanolamine , ethylenediamine, polyethyleneimine], compounds having one or more thiol groups in the molecule, and the like.

When a chain transfer agent is used, the amount used is the crosslinkable monomer (a), water-soluble unsaturated Based on the total weight of the monomer (b) and other monomers (x), preferably 0.0001% by mass or more and 0.05% by mass or less, more preferably 0.0005% by mass or more and 0.02% by mass or less, 0.001% by mass or more and 0.01% by mass or less is particularly preferable.

Furthermore, it may be used in combination with a living radical polymerization method. The living radical polymerization method is not particularly limited, but includes, for example, a method using a nitroxide compound, a method using a transition metal complex, a method using an addition-fragmentation type chain transfer agent, and the like.

The monomer concentration in the aqueous monomer solution during polymerization is preferably 20% by mass or more and 80% by mass or less, more preferably 25% by mass or more and 75% by mass or less, based on the mass of the aqueous monomer solution in aqueous solution polymerization, and 30% by mass. % or more and 70 mass % or less is particularly preferable.

The obtained polymer may be used as an aqueous solution or after dilution, or the obtained polymer may be pulverized once and made into an aqueous solution at the time of use.

When the polymer of this embodiment is in the state of an aqueous solution, the viscosity of the polymer measured with a rotational viscometer at 25° C. is preferably 5 mPa·s or more and 10000 mPa·s or less, and 10 mPa·s or more and 9000 mPa·s or less. is more preferable, and 15 mPa·s or more and 8000 mPa·s or less is even more preferable.
When the viscosity of the polymer is 5 mPa·s or more and 10000 mPa·s or less, it has a high affinity with sludge and can form coarse and firm flocs.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these. In addition, "%" in an example shows the mass % unless otherwise indicated.

In Examples and Comparative Examples, the 0.5% viscosity of the crosslinked polymer flocculant, the 0.5% salt viscosity, the insoluble content of the 0.5% by mass aqueous solution, and the storage elastic modulus of the water-containing material were measured. It was obtained by measuring by the method shown below for a crosslinked polymer flocculant with a shape.

(Measurement of 0.5% viscosity)
2.5 g of sample was dissolved in water to prepare 500 g of 0.5% polymer aqueous solution. Using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd.), the viscosity of the aqueous polymer solution was measured after 5 minutes at a temperature of 25° C. and a rotational speed of 60 rpm.

(Measurement of 0.5% salt viscosity)
2.5 g of sample was dissolved in 4% aqueous sodium chloride solution to prepare 500 g of 0.5% aqueous polymer solution. Using a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd.), the salt viscosity of the aqueous polymer solution was measured after 5 minutes at a temperature of 25° C. and a rotational speed of 60 rpm.

(Measurement of insoluble content in 0.5% by mass aqueous solution)
The entire amount (500 g) of the 0.5% aqueous polymer solution obtained above was filtered through a sieve with a diameter of 20 cm and an opening of 180 μm square, and water was wiped off. It was measured.

(Storage elastic modulus of hydrous gel)
Using a rheometer (MARS III manufactured by HAAKE), strain was applied to the gel-like water-containing material, which is the insoluble portion of the 0.5% by mass aqueous solution of the crosslinked polymer flocculant remaining on the sieve obtained earlier. The storage modulus was measured by the modulus dependent measurement method. Specifically, the storage elastic modulus G1 (Pas) was measured at a temperature of 25° C., a jig parallel plate (20 mmφ, notched), and a strain rate of 0.001% to 10% at a frequency of 1 Hz.

<Synthesis Example 1>
10.0 g of allyl bromide and 40.0 g of tetrahydrofuran (THF) were put into a 100 mL beaker to obtain a THF solution of allyl bromide. The resulting THF solution of allyl bromide was transferred to a 100 mL dropping funnel. Next, 10.85 g of dimethylaminopropylacrylamide (DMPAA) and 40.0 g of tetrahydrofuran (THF) were put into a 200 mL eggplant flask to obtain a THF solution of DMPAA.
Further, the THF solution of allyl bromide was added dropwise to the THF solution of DMPAA over 20 minutes while stirring the THF solution of DMPAA with a magnetic stirrer. After stirring was completed, the mixture was allowed to stand for 12 hours, the supernatant was removed, and the mixture was decanted with 200 mL of THF.
Thereafter, the resulting precipitate was dried under reduced pressure to obtain a white to pale yellow crosslinkable monomer (a).

[Test 1: Production of cationic polymer flocculant]
Cationic polymer flocculants of each example and each comparative example were produced by the method shown below. Abbreviations of polymerizable monomers and copolymerizable monomer components in Table 1 and the following description are as follows.
AAm: acrylamide (manufactured by Wako Pure Chemical Industries, Ltd.)
DME: methyl chloride salt of dimethylaminoethyl acrylate (manufactured by Osaka Organic Co., Ltd.)
MBAAM: methylene bisacrylamide (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Example 1-1>
250.0 g of AAm and 0.015 g of crosslinkable monomer (a) are put into a 1000 mL brown bottle, and distilled water is added so that the total monomer concentration is 50% and the total mass is 500 g, and the monomer reaction solution ( AAm/crosslinkable monomer (a)=99.99/0.01(%)) was prepared.
Furthermore, DAROCUR-1173 (hereinafter abbreviated as "D-1173") (manufactured by Ciba) as a photoinitiator, and hypophosphorous acid (hereinafter abbreviated as "HPA") as a chain transfer agent (Kanto Chemical Co., Ltd.) ) was added to the total mass of the monomer reaction solution so as to be 20 ppm and 60 ppm, respectively, and the solution temperature was adjusted to 25° C. while nitrogen gas was blown therein for 15 minutes. Thereafter, the monomer reaction solution was transferred to a stainless reaction vessel and irradiated with a chemical lamp at an irradiation intensity of 0.2 W/m ² for 20 minutes to carry out polymerization. As a result, a hydrous gel-like polymer was obtained.
This hydrous gel-like polymer was taken out from the container and crushed using a small meat chopper. This was dried at a temperature of 70° C. for 16 hours and pulverized to obtain a powdery polymer (A-1).

<Example 1-2>
Polymer (A-2) was obtained in the same manner as in Example 1-1, except that the amount of HPA was changed to 30 ppm.

<Example 1-3>
Example 1-1 except that the amount of crosslinkable monomer (a) was changed to 0.0375 g (AAm/crosslinkable monomer (a) = 99.985/0.015 (%)). A similar operation was performed to obtain a polymer.

<Example 1-4>
AAm 45 g, 80 wt% DME aqueous solution 318.75 g, and crosslinkable monomer (III-1) 0.035 g were put into a 1000 mL brown bottle, and distilled water was added so that the total monomer concentration was 60% and the total mass was 500 g. was added to prepare a monomer reaction solution (AAm/DME/crosslinkable monomer (III-1)=14.998/84.990/0.012(%)).
Furthermore, D-1173 as a photoinitiator and hypophosphorous acid as a chain transfer agent were added so as to be 130 ppm and 30 ppm, respectively, with respect to the total mass of the monomer reaction solution, and 15% nitrogen gas was added. The solution temperature was adjusted to 25°C while bubbling for 1 minute.
Thereafter, the monomer reaction solution was transferred to a stainless reaction vessel and irradiated with a chemical lamp at an irradiation intensity of 0.2 W/m ² for 20 minutes to carry out polymerization. As a result, a hydrous gel-like polymer was obtained.
This hydrous gel-like polymer was taken out from the container and crushed using a small meat chopper. This was dried at a temperature of 70° C. for 16 hours and pulverized to obtain a powdery polymer (A-3).

<Comparative Example 1-1>
Example 1-1 except that the amount of crosslinkable monomer (a) was changed to 0.075 g (AAm/crosslinkable monomer (a) = 99.97/0.03 (%)). A polymer (B-1) was obtained by performing the same operation.

<Comparative Example 1-2>
Example 1-1 except that the amount of crosslinkable monomer (a) was changed to 0.25 g (AAm/crosslinkable monomer (a) = 99.9/0.1 (%)). A similar operation was performed to obtain a polymer.

<Comparative Example 1-3>
Polymer (B-2) was obtained in the same manner as in Example 1-1 except that the crosslinkable monomer was changed to MBAAM (AAm/MBAAM=99.9966/0.0034).

<Comparative Example 1-4>
Except for changing the input amount of the crosslinkable monomer (a) to 0.14 g (AAm / DME / crosslinkable monomer (III-1) = 14.970/84.940/0.090 (%)) performed the same operation as in Example 1-4 to obtain a polymer (B-3).

For each (co)polymer obtained in Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-4, 0.5% viscosity, 0.5% salt viscosity, 0.5% by mass aqueous solution The insoluble content and the storage elastic modulus G1 (Pas) of the hydrous material were measured. Table 1 shows the results.

[Test 2: Sludge treatment]
A 1% kaolinite aqueous solution was prepared as a model sample of sludge, and 300 mL of this kaolinite aqueous solution was collected in a 500 mL beaker. Then, the types of polymers shown in Table 2 were added to a 0.5% aqueous polymer solution with distilled water, and this aqueous polymer solution was added to the aqueous kaolinite solution in the amount shown in Table 2. Next, this kaolinite aqueous solution is stirred 10 times with a metal spatula to generate flocs, and the flocs are passed through a 2 mm square sieve. The others were determined to have a floc grain size of 2 mm or more. The floc settling time was also determined. The floc particle size and settling time are shown in Table 2.

Furthermore, as a sludge sample, digested sludge from a certain sewage treatment plant was prepared, and 300 mL of this digested sludge was collected in a 500 mL beaker. Then, the types of polymers shown in Table 3 were added to a 0.5% polymer aqueous solution with distilled water, and this aqueous polymer solution was added to the digested sludge in the amounts shown in Table 3. Next, the digested sludge is stirred with a three-one motor at a rotation speed of 800 rpm for 20 seconds, and then stirred with a spatula for 10 rotations to generate flocs. Those that passed were judged to have a floc particle size of less than 15 mm, and those that did not pass were judged to have a floc particle size of 15 m or more.

In addition, the floc strength was determined as follows. Table 3 shows the particle size and strength of the flocs.
(Floc strength)
A: When the flock is crushed by hand, it feels like it bounces back.
B: When the flock is crushed by hand, it does not rebound and does not feel elastic.

As is clear from Table 2, model sludge was flocculated using the polymer (A-1) obtained in Example 1-1 and the polymer (A-2) obtained in Example 1-2. In the cases (Examples 2-1 and 2-2), the resulting flocs had a large particle size, a fast sedimentation time, and good drainage.
Further, as is clear from Table 3, when the actual sludge was flocculated using the polymer (A-3) obtained in Example 1-4 (Example 2-3), the obtained floc The grain size was large and the strength was high. Therefore, it was confirmed that the polymers obtained in Examples 1-1, 1-2, and 1-4 had excellent aggregation performance.
On the other hand, when using the polymer (B-1) obtained in Comparative Example 1-1 and the polymer (B-2) obtained in Comparative Example 1-3 (Comparative Examples 2-1 and 2-2) had a smaller particle size of flocs, a lower sedimentation velocity, and poor drainage compared to those of Examples. Furthermore, when the polymer (B-3) obtained in Comparative Example 1-4 was used (Comparative Example 2-3), the particle size of the flocs was smaller and the strength was lower than in Examples. Therefore, the polymers obtained in Comparative Examples 1-1, 1-2, and 1-3 were inferior in flocculation performance to those of Examples.

As described in detail above, according to the present invention, coarse flocs can be generated, and the branched polymer has a low aqueous solution viscosity relative to its molecular weight and is excellent in handleability. It is useful in fields such as cross-linked polymer flocculants that need to be mixed in, and paper strength agents.

Claims (5)

A crosslinked polymer flocculant having a gel-like water-containing substance,
The total amount (500 g) of the 0.5% by mass aqueous solution of the crosslinked polymer flocculant is filtered through a sieve with a diameter of 20 cm and an opening of 180 μm square, and the moisture is wiped off. Strain rate dependence measurement when applying a strain rate of 0.001% to 10% at a frequency of 1 Hz with a jig parallel plate (20 mmφ, notched) at 25 ° C. using a rheometer against a gel-like water-containing material. The maximum value of the storage elastic modulus G1 (Pas) when measured satisfies the following formula (III-1) , and the total amount (500 g) in 500 g of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant is measured to have a diameter of 20 cm. , Filter through a 180 μm square sieve, wipe off moisture, and the amount of insoluble matter remaining on the sieve is 60 g or more and 400 g or less with respect to 500 g of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant. A crosslinkable monomer (a) component having a structure derived from the following formula (III-1) in the molecule, and at least one water-soluble unsaturated monomer selected from methyl chloride salts of acrylamide and dimethylaminoethyl acrylate A crosslinked polymer flocculant containing the polymer (b).
3<G1<800 Expression (1)

The concentration of the crosslinkable monomer (a) component is 0.0035 to 0.025% by mass with respect to 100% by mass of the water-soluble unsaturated monomer (b), according to claim 1 crosslinked polymer flocculant. The crosslinked polymer flocculant according to claim 1 or 2, further comprising one or more water-soluble unsaturated monomer (b)-derived components having one polymerizable unsaturated bond in the molecule. . A crosslinkable monomer (a) component having a structure derived from the following formula (III-1) in the molecule, and at least one water-soluble unsaturated monomer selected from acrylamide and methyl chloride salts of dimethylaminoethyl acrylate A method for producing a crosslinked polymer flocculant, comprising dissolving a crosslinked polymer flocculant component containing (b) in water and polymerizing it in a homogeneous system,
The total amount (500 g) in 500 g of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant was filtered through a sieve with a diameter of 20 cm and an opening of 180 μm square, and water was wiped off. A method for producing a crosslinked polymer flocculant, wherein the amount is 60 g or more and 400 g or less with respect to 500 g of a 0.5% by mass aqueous solution of the crosslinked polymer flocculant.

5. The method for producing a crosslinked polymer flocculant according to claim 4 , further comprising dissolving the water-soluble unsaturated monomer (b) in water and conducting homogenous polymerization.