JP5791440B2 - Carboxyl group-containing copolymer and method for producing the same - Google Patents

Description

The present invention relates to a carboxyl group-containing copolymer and a method for producing the same.

  In recent years, it is important to recycle waste paper (printed waste paper) as a raw material for papermaking from the viewpoints of shortage of pulp resources and rising prices, environmental protection, waste management, effective use of resources (resource saving, energy saving), etc. Sexuality is increasing. Along with this, development of a deinking treatment method capable of obtaining recycled pulp having quality similar to virgin pulp from waste paper is required in response to diversification of printing technology and method, ink composition, properties of waste paper, and the like. .

  For example, Patent Document 1 discloses a deinking agent for used paper recycling containing a copolymer of an anionic monomer and a hydrophobic monomer as an active ingredient. Examples of the anionic monomer include acrylic acid, maleic acid, and maleamic acid, and examples of the hydrophobic monomer include alkenes having 5 to 18 carbon atoms, styrene, and substituents having 1 to 12 carbon atoms. Styrene derivatives having the following are exemplified. Patent Document 1 discloses that the deinking agent exhibits a good deinking effect.

  For example, Patent Document 2 discloses at least the following formula:

(In the formula, R ₁ and R ₂ each represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and may be the same or different, and M is a hydrogen atom, an alkali metal cation, an alkaline earth metal cation, or an ammonium cation. Or a polymer having a molecular weight of 1,000 to 1,000,000 derived from a single α-hydroxyacrylic acid, and (1) a linear or branched alkyl group having 4 to 22 carbon atoms. Alternatively, a deinking agent containing a derivative obtained by adding an alkylene oxide to an alcohol having an alkenyl group (2) one or two linear or branched alkyl or alkenyl groups having 4 to 22 carbon atoms, or allyl groups A deinking agent comprising a derivative obtained by adding an alkylene oxide to an individual phenol (3) a dihydric or higher polyhydric alcohol or Is a deinking agent containing a derivative obtained by adding an alkylene oxide to a dihydric or higher polyhydric alcohol. (4) Adding an alkylene oxide to a compound obtained by adding styrene to a compound containing a phenolic OH. (5) Deinking agent containing a derivative obtained by adding alkylene oxide to a compound obtained by multiplying a compound containing phenolic OH with formalin (6) ) A deinking agent containing a derivative obtained by adding alkylene oxide to an amine having one or two linear or branched alkyl or alkenyl groups having 4 to 22 carbon atoms (7) Derivative of (1) above An esterification reaction at a high temperature with a higher fatty acid having 7 to 22 carbon atoms using an esterification catalyst on the terminal OH group of the polyalkylene oxide, or Deinking agent containing a derivative obtained by dehydrochlorination reaction with a secondary fatty acid chloride or a transesterification reaction using a higher alcohol ester of a lower alcohol (8) The terminal OH group of the polyalkylene oxide of the derivative of (2) Deinking agent containing a derivative obtained by esterification according to the above (7) (9) A dihydric or higher polyhydric alcohol or a derivative obtained by adding alkylene oxide to a dihydric or higher polyhydric alcohol A deinking agent containing a derivative obtained by esterifying the terminal OH group according to the above (7) (10) Obtained by esterifying the derivative of the above (4) according to the above (7) Deinking agent containing the obtained derivative (11) Deinking agent containing the derivative obtained by esterifying the derivative of (5) according to (7) (12) Derivative of (6) Before A deinking agent comprising a derivative obtained by esterification according to (7) (13) a dihydric or higher polyhydric alcohol or a derivative obtained by adding an alkylene oxide to a dihydric or higher polyhydric alcohol; Deinking agent containing a derivative obtained by adding an alkylene oxide to a fatty acid glyceride or a mixture with a higher fatty acid ester compound of a monohydric or polyhydric alcohol (14) A monohydric alcohol or an alkylene oxide to a monohydric alcohol A deinking agent (15) containing a derivative obtained by adding an alkylene oxide to a mixture of the derivative obtained by addition and the fatty acid glyceride shown in the above (13) or a higher fatty acid ester compound of mono- or polyhydric alcohol. ) Amino alcohol or a derivative obtained by adding alkylene oxide to amino alcohol A deinking agent containing a derivative obtained by adding an alkylene oxide to a mixture of the fatty acid glyceride or the higher fatty acid ester compound of a monohydric or polyhydric alcohol shown in the above (13). (16) An alkylene oxide is added to the higher fatty acid. There is disclosed a waste paper recycling method characterized in that at least one deinking agent selected from deinking agents containing a derivative obtained by addition is used in combination. In the cited document 2, according to the above-mentioned waste paper recycling treatment method, a remarkable peroxide stabilizing effect is promoted in bleaching with peroxide, and a high added value recycled waste paper with high whiteness and little residual ink is used. It is disclosed that can be obtained.

JP 59-173392 A JP-A-6-116886

Thus, although various polymers have been reported in the past, there is a demand for the development of a removal agent having better deinking performance.
An object of the present invention is to provide a polymer having good deinking performance.

As a result of intensive studies on various polymers (including copolymers) in order to achieve the above object, the present inventors have found that structural units and carboxyl group-containing units derived from specific ether bond-containing monomers. It has been found that a copolymer in which a structural unit derived from a monomer is introduced at a specific ratio has excellent deinking performance. Based on the above findings, the present invention has been completed.
That is, the present invention relates to a structural unit (a) derived from an ether bond-containing monomer (A) represented by the following general formula (1) of 1% by mass to 50% by mass, 50% by mass to 99% by mass. It is a carboxyl group-containing copolymer having the structural unit (b) derived from the following carboxyl group-containing monomer (B) as an essential structural unit.

In the formula, R ₁ represents a hydrogen atom or a CH ₃ group, R ₂ represents a CH ₂ group, a CH ₂ CH ₂ group or a single bond, and R ₃ represents an organic group having 1 to 20 carbon atoms.

The carboxyl group-containing copolymer of the present invention has excellent deinking performance. Therefore, for example, it can be usefully used as a deinking agent.

Hereinafter, the present invention will be described in detail.

[Carboxyl group-containing copolymer of the present invention]
<Ether bond-containing monomer as monomer (A)>
The carboxyl group-containing copolymer of the present invention is required to have the structural unit (a) derived from the ether bond-containing monomer (A) represented by the following general formula (1) at a specific ratio.

In the general formula (1), R ₁ represents a hydrogen atom or a CH ₃ group, R ₂ represents a CH ₂ group, a CH ₂ CH ₂ group or a single bond, and R ₃ represents an organic compound having 1 to 20 carbon atoms. Represents a group.

In the general formula (1), R ₂ represents a CH ₂ group, a CH ₂ CH ₂ group, or a single bond, and these groups tend to improve the deinking performance. In addition, because hydrolysis resistance is superior compared to carbonyl groups and amide groups, for example, decomposition is suppressed even under heating conditions such as during polymerization and during the manufacture of various products including polymers. , Improving the quality of the product used (less variation).
R ₂ is preferably a CH ₂ group or a CH ₂ CH ₂ group because the effect of improving the deinking performance of the obtained copolymer is higher.

In the general formula (1), R ₁ is preferably a hydrogen atom because the resulting copolymer tends to have a higher deinking effect.
As described above, R ₃ is an organic group having 1 to 20 carbon atoms, but R ₃ includes a functional group such as an amino group, an amide group, a hydroxyl group, an alkoxide group, a sulfonic acid group, a carbonyl group, or a carboxyl group. You can leave. R ₃ may contain an ether bond, a sulfide bond, an ester bond, or an amide bond. However, since the effect of improving the deinking performance of the obtained copolymer tends to be high, R ₃ preferably does not contain a hetero atom.
The organic group is preferably a substituted or unsubstituted alkyl group, an aryl group, or an alkenyl group because the effect of improving the deinking performance of the resulting copolymer is high. An unsubstituted alkyl group, an aryl group, More preferred is an alkenyl group.
The substituted alkyl group, aryl group, and alkenyl group represent a group in which some or all of the hydrogen atoms of the alkyl group, aryl group, or alkenyl group are substituted with a functional group such as the above functional group. .

R ₃ is preferably an organic group having 2 to 18 carbon atoms, more preferably an organic group having 3 to 16 carbon atoms, and particularly preferably an organic group having 4 to 14 carbon atoms.

Specific examples of R ₃ include methyl, isopropyl, n-propyl, n-butyl, isobutyl, tertiary butyl, octyl, lauryl, stearyl, cyclohexyl, and 2-ethylhexyl alkyl. Groups: alkenyl groups such as butylene, octylene and nonylene; aryl groups such as phenyl, phenethyl, 2,3- or 2,4-xylyl, mesityl and naphthyl.

  As the ether bond-containing monomer (A) represented by the general formula (1), a commercially available one may be used. For example, an alcohol is added to a halide such as allyl chloride, methallyl chloride, or isoprenyl chloride. Method of addition; You may manufacture by the method etc. with which alcohol, such as allyl alcohol, methallyl alcohol, and isoprenol, and alkyl halide etc. are made to react.

  Examples of the monomer (A) include allyl methyl ether, allyl isopropyl ether, allyl butyl ether (allyl normal butyl ether), allyl isobutyl ether, allyl tertiary butyl ether, allyl octyl ether, methallyl butyl ether, and methallyl octyl ether. (Meth) allyl alkyl ether; (meth) allyl aryl ethers such as allyl phenyl ether, allyl naphthyl ether, methallyl phenyl ether; isoprenyl alkyl ethers such as isoprenyl butyl ether and isoprenyl octyl ether; Prenyl aryl ether; alkyl vinyl ethers such as ethyl vinyl ether, isobutyl vinyl ether, octyl vinyl ether; Aryl vinyl ethers such as vinyl ether; and the like. Since the deinking performance of the obtained polymer is improved, (meth) allyl alkyl ether, (meth) allyl aryl ether, isoprenyl alkyl ether, and isoprenyl aryl ether are preferable.

The structural unit (a) is a monomer (A), that is, in the above formula (1), a polymerizable unsaturated double bond (CH ₂ ═C (R ₁ ) —) is a single bond (—CH ₂ —). C (R ₁ )-), which is represented by the following general formula (2).

In General Formula (2), R ₁ represents a hydrogen atom or a CH ₃ group, R ₂ represents a CH ₂ group, a CH ₂ CH ₂ group, or a single bond, and R ₃ represents an organic compound having 1 to 20 carbon atoms. Represents a group.

  The copolymer of the present invention may contain only one type of structural unit (a), but may contain two or more types.

  The carboxyl group-containing copolymer of the present invention comprises all structural monomers (ether bond-containing monomers) derived from the ether bond-containing monomer (A) represented by the general formula (1). (A), the sum of structural units derived from the carboxyl group-containing monomer (B) and other monomers (E) described later (ie, the structural unit (a), the structural unit (b), the structural unit ( It is essential to have a ratio of 1% by mass to 50% by mass with respect to 100% by mass in the sum of e). If the structural unit (a) is within the above range, the deinking performance of the copolymer tends to be improved. The ratio of the structural unit (a) to the total of 100% by mass of the structural units derived from all monomers is preferably 2% by mass or more and 40% by mass or less, and more preferably 3% by mass or more and 30% by mass or less. .

<Carboxyl group-containing monomer as monomer (B)>
The carboxyl group-containing copolymer of the present invention is required to have the structural unit (b) derived from the carboxyl group-containing monomer (B) at a specific ratio.

  The carboxyl group-containing monomer (B) of the present invention is a monomer containing as essential components 1) a carbon-carbon unsaturated double bond and 2) a carboxyl group and / or a salt thereof (provided that the monomer (A) The monomer belonging to) is excluded from the monomer (B)). Specifically, unsaturated monocarboxylic acids and their salts such as acrylic acid, methacrylic acid, crotonic acid, α-hydroxyacrylic acid, α-hydroxymethylacrylic acid and derivatives thereof; itaconic acid, fumaric acid, malee Examples thereof include unsaturated dicarboxylic acids such as acid and 2-methyleneglutaric acid, and salts thereof.

  The salt is a metal salt, an ammonium salt, or an organic amine salt. Examples of the metal salt include alkali metal salts such as sodium salt, lithium salt and potassium salt; alkaline earth metal salts such as magnesium salt and calcium salt; salts such as aluminum and iron. Organic amine salts include monoethanolamine salts, diethanolamine salts, triethanolamine salts and other alkanolamine salts; monoethylamine salts, diethylamine salts, triethylamine salts and other alkylamine salts; ethylenediamine salts, triethylenediamine salts and other polyamines And salts of organic amines such as Among the salts, alkali metal salts such as sodium and potassium are preferable because the deinking performance of the copolymer tends to be improved.

  Among the carboxyl group-containing monomers (B), acrylic acid, acrylate, maleic acid, and maleate are preferred because the effect of improving the deinking performance of the copolymer is high, and acrylic acid and acrylate are preferred. More preferably, it is essential.

  The copolymer of the present invention may contain only one type of structural unit (b), but may contain two or more types.

The structural unit (b) has a structure in which the unsaturated double bond (CH ₂ ═C (R ₁ ) —) of the monomer (B) is a single bond (—CH ₂ —C (R ₁ ) —). It is.

  In the carboxyl group-containing copolymer of the present invention, the structural unit (b) derived from the carboxyl group-containing monomer (B) is 50% by mass or more with respect to a total of 100% by mass of the structural units derived from all monomers. It is essential to have a ratio of 99% by mass or less. If the structural unit (b) is within the above range, the deinking performance tends to be improved. The ratio of the structural unit (b) to the total of 100% by mass of the structural units derived from all monomers is preferably 60% by mass to 98% by mass, and more preferably 70% by mass to 97% by mass. .

In addition, in this invention, when calculating the mass ratio (mass%) with respect to the sum total of the structural unit derived from all the monomers of the structural unit (b) derived from a carboxyl group-containing monomer (B), a corresponding acid It shall be calculated as a conversion. For example, if the structural unit is —CH ₂ —CH (COONa) — derived from sodium acrylate, the structural unit —CH ₂ —CH (COOH) — derived from acrylic acid, which is the corresponding acid, is represented by a mass ratio (mass% ). Similarly, also when calculating the mass ratio (mass%) with respect to all the monomers of a carboxyl group-containing monomer (B), it shall calculate as a corresponding acid conversion. For example, if it is sodium acrylate, a mass ratio (mass%) is calculated as acrylic acid which is a corresponding acid.
Furthermore, when calculating the mass ratio (% by mass) of the structural unit derived from the acid group-containing monomer other than the carboxyl group-containing monomer (B) to the structural unit derived from all monomers, the corresponding acid When calculating the mass ratio (% by mass) of the acid group-containing monomer other than the carboxyl group-containing monomer (B) with respect to all the monomers, it is also calculated as the corresponding acid conversion. And The structural unit derived from the amino group-containing monomer and the amino group-containing monomer are also mass-calculated as the corresponding structural unit derived from the unneutralized amine and the unneutralized amine. For example, in the case of vinylamine hydrochloride, the mass ratio (% by mass) is calculated as vinylamine which is the corresponding unneutralized amine.

<Other monomers>
The carboxyl group-containing copolymer of the present invention may have a structural unit (e) derived from another monomer (E).
The other monomer (E) when the carboxyl group-containing copolymer of the present invention contains another monomer (E) can be copolymerized with the monomer (A) and / or (B). There is no particular limitation as long as it is anything, and it is appropriately selected depending on the desired effect. Specifically, N-vinyl monomers such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, N-vinyl-N-methylformamide, N-vinyl-N-methylacetamide, N-vinyloxazolidone, etc. Amide monomers such as (meth) acrylamide, N, N-dimethylacrylamide and N-isopropylacrylamide; (meth) acrylics such as butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and dodecyl (meth) acrylate Acid alkyl ester monomers; hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, 2 -Hydro (Metal such as Sibutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, α-hydroxymethylethyl (meth) acrylate, hydroxypentyl (meth) acrylate, hydroxyneopentyl (meth) acrylate, hydroxyhexyl (meth) acrylate, etc. ) Hydroxyalkyl monomers based on acrylic acid; vinyl aromatic amino group-containing monomers having a heterocyclic aromatic hydrocarbon group and a polymerizable group such as vinylpyridine and vinylimidazole, and quaternized products and salts thereof; Allylamines such as diallylamine and diallyldimethylamine, and quaternized compounds and salts thereof; (i) (ii) dimethylamine, diethylamine on the epoxy ring of (meth) allyl glycidyl ether, isoprenyl glycidyl ether, vinyl glycidyl ether It is obtained by reacting amines such as dialkylamines such as diisopropylamine and di-n-butylamine, alkanolamines such as diethanolamine and diisopropanolamine, aminocarboxylic acids such as iminodiacetic acid and glycine, and cyclic amines such as morpholine and pyrrole. And quaternized compounds and salts thereof; vinyl aryl monomers such as styrene, indene and vinylaniline; isobutylene and vinyl acetate.
Moreover, the said other monomer (E) may be used individually by 1 type, or may be used with the form of a 2 or more types of mixture.

The carboxyl group-containing copolymer of the present invention is optional, but the structural unit (e) is 0% by mass or more and 40% by mass or less with respect to 100% by mass in total of the structural units derived from all monomers. You may have in a ratio. The ratio of the structural unit (e) to the total of 100% by mass of the structural units derived from all monomers is preferably 0% by mass or more and 20% by mass or less, more preferably 0% by mass or more and 10% by mass or less. It is.
In the carboxyl group-containing copolymer of the present invention, the structural units (a) and (b), and if necessary, the structural unit (e) may be introduced at a specific ratio as described above. The structural unit may exist in either a block shape or a random shape. Moreover, the weight average molecular weight of the carboxyl group-containing copolymer of the present invention can be appropriately set and is not particularly limited. Specifically, the weight average molecular weight of the carboxyl group-containing copolymer is preferably 2,000 to 200,000, more preferably 3,000 to 60,000, and most preferably 4,000 to 30, 000. If the weight average molecular weight is within the above range, the deinking performance tends to be improved. In addition, in this specification, a weight average molecular weight is a measured value by GPC (gel permeation chromatography), and was measured according to the method described in an Example.

[Carboxyl group-containing copolymer composition of the present invention (also simply referred to as polymer composition)]
The carboxyl group-containing copolymer composition of the present invention contains the carboxyl group-containing copolymer of the present invention as an essential component, and components other than the carboxyl group-containing copolymer are optional. Contains one or more selected from agent residues, residual monomers, by-products during polymerization, and moisture. The form of a preferable carboxyl group-containing copolymer composition is a form containing 20 to 80% by mass of a carboxyl group-containing copolymer and 20 to 80% by mass of water.
In the polymer composition of the present invention, the total amount of residual monomers is preferably 0 to 15000 ppm, more preferably 0 to 10,000 ppm, in terms of solid content of the polymer composition.

[Production method of carboxyl group-containing copolymer of the present invention]
As long as there is no notice in particular, the manufacturing method of the carboxyl group-containing copolymer of this invention can use the method which carried out similarly or modified the well-known polymerization method. As a method for producing the carboxyl group-containing copolymer of the present invention, an ether bond-containing monomer (A) and a monomer (monomer component) containing the carboxyl group-containing monomer (B) as essential components are used. It can manufacture by including the process to superpose | polymerize (polymerization process) essential. Moreover, when copolymerizing a monomer component, you may further copolymerize the said other monomer (E) as needed.

  In such a production method, the monomer component may be copolymerized using a polymerization initiator. In addition, the kind and usage-amount of the monomer contained in a monomer component are set suitably so that the structural unit which comprises a carboxyl group-containing copolymer may become as above-mentioned. That is, the composition ratio of each monomer forming the carboxyl group-containing copolymer is such that all monomers (that is, ether bond-containing monomer (A), carboxyl group-containing monomer (B), other Monomer (E)), ether bond-containing monomer (A) is 1% by mass or more and 50% by mass or less, and carboxyl group-containing monomer (B) is 50% by mass or more and 99% by mass or less It is. As described above, when the other monomers (E) copolymerizable with these are further added in an amount of 0% by mass or more and 40% by mass or less when the total of all the monomers is 100% by mass. May be used. More preferably, the ether bond-containing monomer (A) is 2 mass% to 40 mass%, the carboxyl group-containing monomer (B) is 60 mass% to 98 mass%, and the other monomer (E). Is 0% by mass or more and 20% by mass or less, more preferably 3% by mass or more and 30% by mass or less of the ether bond-containing monomer (A), and 70% by mass or more of the carboxyl group-containing monomer (B). 97 mass% or less, and other monomer (E) is 0 mass% or more and 10 mass% or less. The total amount of the monomers (A), (B) and (E) is 100% by mass.

  In the present invention, the copolymerization of the monomers (A) to (B) and, if necessary, another monomer (E) is a method and / or chain using water in 50% by mass or more of the solvent used. The method is preferably carried out in the presence of a transfer agent, more preferably 50% by weight or more of the solvent used and water in the presence of a chain transfer agent. At this time, by using water in 50% by mass or more of the solvent to be used, the amount of the organic solvent used for the polymerization can be suppressed, so that there is an advantage that the organic solvent can be easily distilled off after the completion of the polymerization. Moreover, when a chain transfer agent is used, it is possible to suppress the carboxyl group-containing copolymer to be produced from being unnecessarily high in molecular weight and to efficiently produce a low molecular weight carboxyl group-containing copolymer. There is. In particular, when bisulfite (salt) is used as a chain transfer agent, the sulfonic acid group can be quantitatively introduced at the end of the resulting carboxyl group-containing copolymer, and the deinking performance is described in detail below. Can be improved.

  Therefore, a preferable form of the production method of the present invention is an ether bond-containing monomer (A) of the formula (1) of 1% by mass or more and 50% by mass or less, and a formula (2) of 50% by mass or more and 99% by mass or less Carboxyl group-containing monomer (B), 0% to 40% by weight of other monomer (E) if necessary (however, the sum of monomers (A), (B) and (E) The ratio is 100% by mass), which is a method for producing a carboxyl group-containing copolymer comprising a step of carrying out a polymerization reaction using water in 50% by mass or more of a solvent to be used and using a chain transfer agent.

  Although it does not restrict | limit especially as a solvent used with the manufacturing method of this invention, The thing containing water in the ratio of 50 mass% with respect to the whole solvent to be used is preferable. From the viewpoint of improving the solubility of the monomer used for polymerization in a solvent, an organic solvent may be added as necessary. Examples of the organic solvent that can be used include lower alcohols such as methanol, ethanol, and isopropyl alcohol; lower ketones such as acetone, methyl ethyl ketone, and diethyl ketone; ethers such as dimethyl ether and dioxane; amides such as dimethylformaldehyde. . These solvents may be used alone or in the form of a mixture of two or more. In the present invention, the amount of water is preferably 80% by mass or more, and most preferably water alone (ie, 100% by mass) with respect to the total amount of solvent used.

  As the usage-amount of the said solvent, 40-200 mass% is preferable with respect to a total of 100 mass% of all the monomers. More preferably, it is 45 mass% or more, More preferably, it is 50 mass% or more. Moreover, More preferably, it is 180 mass% or less, More preferably, it is 150 mass% or less. When the amount of the solvent used is 40% by mass or less, the molecular weight of the obtained copolymer may be increased. When the amount exceeds 200% by mass, the concentration of the obtained copolymer is decreased, and the solvent needs to be removed. There is a risk.

  As the initiator used in the production method of the present invention, known initiators can be used, for example, hydrogen peroxide; persulfates such as sodium persulfate, potassium persulfate, ammonium persulfate; 2,2 ′ -Azobis (2-amidinopropane) hydrochloride, 4,4'-azobis-4-cyanoparerenic acid, azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), etc. The organic peroxides such as benzoyl peroxide, lauroyl peroxide, peracetic acid, di-t-butyl peroxide and cumene hydroperoxide are preferred. Of these polymerization initiators, hydrogen peroxide and persulfate are preferable, and the residual monomer can be reduced, and persulfate is most preferable. These polymerization initiators may be used alone or in the form of a mixture of two or more.

  The amount of the initiator used is not particularly limited as long as it is an amount capable of initiating copolymerization of the monomers (A) and (B) and, if necessary, other monomers (E). It is preferable that it is 10 g or less, more preferably 1 to 5 g with respect to 1 mol of all monomer components consisting of A), (B) and other monomer (E) if necessary.

In the production method of the present invention, the copolymerization is preferably performed in the presence of a chain transfer agent. The chain transfer agent that can be used in this case is not particularly limited as long as it is a compound capable of adjusting the molecular weight, and a known chain transfer agent can be used. Specifically, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropion, 3-mercaptopropion, thiomalic acid, octyl thioglycolate, octyl 3-mercaptopropionate, 2-mercaptoethanesulfonic acid, n -Thiol chain transfer agents such as dodecyl mercaptan, octyl mercaptan, butylthioglycolate; Halides such as carbon tetrachloride, methylene chloride, bromoform, bromotrichloroethane; Secondary alcohols such as isopropanol, glycerin; Acids, hypophosphorous acid and salts thereof (sodium hypophosphite, potassium hypophosphite, etc.), sulfurous acid, bisulfite, dithionite, metabisulfite, sulfite, thiosulfate ( Sodium hydrogen sulfite, potassium hydrogen sulfite, Sodium dithionite, potassium dithionite, sodium metabisulfite, metabisulfite potassium, etc.) and the like, and the like lower oxides and salts thereof. The chain transfer agent may be used alone or in the form of a mixture of two or more.
Among these, in the copolymerization reaction according to the present invention, it is preferable to use bisulfite (salt) (including a compound that produces a sulfite by hydrolysis like metabisulfite). Thereby, a sulfonic acid group can be quantitatively introduced into the main chain terminal of the obtained carboxyl group-containing copolymer, and the gel resistance can be improved. The ability to introduce sulfonic acid groups quantitatively indicates that bisulfite (salt) is functioning very well as a chain transfer agent and the like. There is no need to add a transfer agent or the like, and an increase in the production cost of the copolymer is reduced, production efficiency is improved, and impurities can be sufficiently reduced. Further, by adding bisulfurous acid (salt) to the polymerization reaction system, it is possible to suppress the resulting copolymer from having a higher molecular weight than necessary. By using bisulfite (salt), the deinking performance of the resulting polymer tends to be improved.

  The salt in the bisulfite (salt) is a metal salt, an ammonium salt, or an organic amine salt. Among the bisulfites (salts), sodium bisulfite and potassium bisulfite are preferable. Bisulfite (salt) may use only 1 type and may use 2 or more types.

  In the method of the present invention, the amount of the chain transfer agent used is not limited, but preferably the use of all monomers consisting of the monomers (A) and (B) and, if necessary, other monomers (E). It is 1-20g with respect to 1 mol of amounts, More preferably, it is 2-15g. If it is 1 g or less, the molecular weight may not be controlled. Conversely, if it exceeds 20 g, a large amount of impurities may be generated and the polymer content may be lowered. In particular, bisulfite (salt) is used. In some cases, surplus bisulfite (salt) is decomposed in the reaction system, and sulfurous acid gas may be generated. Moreover, there is a risk that it may be economically disadvantageous.

In the production method of the present invention, heavy metal ions may be used as a reaction accelerator. In the present invention, the heavy metal means a metal having a specific gravity of 4 g / cm ³ or more. As said metal ion, iron, cobalt, manganese, chromium, molybdenum, tungsten, copper, silver, gold, lead, platinum, iridium, osmium, palladium, rhodium, ruthenium etc. are preferable, for example. These heavy metals can be used alone or in combination of two or more. Among these, iron is more preferable. The ionic valence of the heavy metal ions is not particularly limited. For example, when iron is used as the heavy metal, the iron ions in the initiator may be Fe ²⁺ or Fe ³⁺ , and these may be combined. May be.

  The heavy metal ions are not particularly limited as long as they are included in the form of ions. However, it is preferable to use a method using a solution in which a heavy metal compound is dissolved because the handleability is excellent. The heavy metal compound used in that case should just contain the heavy metal ion desired to contain in an initiator, and can be determined according to the initiator to be used. When iron is used as the heavy metal ion, a heavy metal compound such as Mohr's salt (Fe (NH4) 2 (SO4) 2 · 6H2O), ferrous sulfate / pentahydrate, ferrous chloride, ferric chloride, etc. It is preferable to use it. Moreover, when using manganese as a heavy metal ion, manganese chloride etc. can be used suitably. In the case of using these heavy metal compounds, since they are water-soluble compounds, they can be used in the form of an aqueous solution and have excellent handleability. The solvent of the solution obtained by dissolving the heavy metal compound is not limited to water, and does not hinder the polymerization reaction in the production of the carboxyl group-containing copolymer of the present invention, and is a heavy metal compound. As long as it dissolves.

  In the polymerization step in the present invention, the amount of heavy metal ions in the case of using the above heavy metal ions, it is preferable that a catalyst amount is included. The amount of catalyst referred to in the present specification means that the catalyst acts as a catalyst rather than being incorporated into the final target product. Specifically, it is 100 ppm or less, preferably 10 ppm or less, more preferably 5 ppm. It is as follows.

  The content of the heavy metal ions is preferably 0.1 to 10 ppm with respect to the total mass of the polymerization reaction solution at the completion of the polymerization reaction. If the content of heavy metal ions is 0.1 ppm or less, the effects of heavy metal ions may not be sufficiently exhibited. On the other hand, if the content of heavy metal ions exceeds 10 ppm, the color tone of the resulting polymer may be deteriorated.

  The time when the polymerization reaction is completed means the time when the polymerization reaction is substantially completed in the polymerization reaction solution and a desired polymer is obtained. For example, when the polymer polymerized in the polymerization reaction solution is neutralized with an alkali component, the content of heavy metal ions is calculated based on the total mass of the polymerization reaction solution after neutralization. When two or more kinds of heavy metal ions are included, the total amount of heavy metal ions may be in the above range.

  As described above, the combination of the initiator and the chain transfer agent is most preferably one or more of persulfate and bisulfite (salt). In this case, the mixing ratio of persulfate and bisulfite (salt) is not particularly limited, but it is preferable to use 0.5 to 5 parts by mass of bisulfite (salt) with respect to 1 part by mass of persulfate. . More preferably, the lower limit of bisulfurous acid (salt) is 1 part by mass, and most preferably 2 parts by mass with respect to 1 part by mass of persulfate. Moreover, the upper limit of bisulfite (salt) is more preferably 4 parts by mass, and most preferably 3 parts by mass with respect to 1 part by mass of persulfate. Here, if the bisulfurous acid (salt) is 0.5 parts by mass or less, the total amount of initiator may increase when the molecular weight is lowered. Conversely, if it exceeds 5 parts by mass, side reactions increase, Impurities may increase.

  The combination of the chain transfer agent, the initiator, and the reaction accelerator is not particularly limited, and can be appropriately selected from the above examples. For example, combinations of chain transfer agent, initiator and reaction accelerator include sodium bisulfite / sodium persulfate, hydrogen peroxide / sodium persulfate, sodium bisulfite / Fe (iron ion), sodium bisulfite / sodium persulfate. / Fe (iron ion), sodium bisulfite / oxygen / Fe (iron ion), sodium hypophosphite / sodium persulfate, and the like are preferable. More preferred are sodium bisulfite / sodium persulfate, sodium bisulfite / sodium persulfate / Fe (iron ion), and most preferred is sodium bisulfite / sodium persulfate / Fe (iron ion).

  The total amount of the chain transfer agent, initiator, and reaction accelerator used is 1 mol of all monomer components consisting of monomers (A) and (B) and, if necessary, other monomers (E). Is preferably 2 to 20 g. By setting it as such a range, the carboxyl group-containing copolymer of this invention can be produced efficiently, and the molecular weight distribution of a carboxyl group-containing copolymer can be made into a desired thing. More preferably, it is 4-18g, More preferably, it is 6-15g.

In the above copolymerization method, as a method of adding a monomer, a polymerization initiator or the like to the reaction vessel, all the monomers are charged into the reaction vessel, and copolymerization is performed by adding the polymerization initiator into the reaction vessel. Method of carrying out: Copolymerization is carried out by charging a part of the monomer into the reaction vessel and adding the polymerization initiator and the remaining monomer continuously or stepwise (preferably continuously) into the reaction vessel. Method to perform; Method to add polymerization solvent to reaction vessel and add whole amount of monomer and polymerization initiator; One of monomers (A) to (B) (for example, monomer (B)) A part of the reaction vessel is charged with the polymerization initiator and the remaining monomer (remaining monomer (B) and monomer (A) and if necessary all of monomer (E)) in the reaction vessel. A method of carrying out copolymerization by adding (preferably continuously) inside is preferable. Among these methods, the molecular weight distribution of the resulting copolymer can be narrowed (sharp), and the deinking performance when used as a deinking agent can be improved. It is preferable to carry out copolymerization by a method in which monomers are successively dropped into a reaction vessel.
The solvent may be partly or wholly charged in the reaction vessel in the initial stage of polymerization, but a part of the solvent may be added (dropped) into the reaction system during the polymerization reaction, or the monomer. Components, initiators, and the like may be added (dropped) into the reaction system during the polymerization reaction together with these components in a form in which the components and initiator are dissolved in advance.

  The copolymerization method can be carried out by commonly used methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization, and is not particularly limited, but solution polymerization is preferred. As described above, the solvent that can be used in this case is preferably a mixed solvent in which 50% by mass of water or water is based on the total solvent. When only water is used, it is preferable in that the solvent removal step can be omitted.

The copolymerization method can be carried out either batchwise or continuously.
In the above copolymerization method, the copolymerization conditions such as the copolymerization temperature are appropriately determined depending on the copolymerization method used, the solvent, and the polymerization initiator, but the copolymerization temperature is usually preferably 0 ° C. or higher. Moreover, it is preferable that it is 150 degrees C or less. More preferably, it is 40 degreeC or more, More preferably, it is 60 degreeC or more, Most preferably, it is 80 degreeC or more. Moreover, More preferably, it is 120 degrees C or less, More preferably, it is 110 degrees C or less. In particular, when bisulfurous acid (salt) is used, the copolymerization temperature is usually 60 ° C to 95 ° C, preferably 70 ° C to 95 ° C, and more preferably 80 ° C to 95 ° C. At this time, at 60 ° C. or lower, there is a possibility that a large amount of impurities derived from bisulfurous acid (salt) is generated. On the contrary, when it exceeds 95 ° C., toxic sulfurous acid gas may be released.

  The copolymerization temperature need not always be kept substantially constant in the polymerization reaction. For example, the polymerization is started from room temperature, the temperature is increased to a set temperature at an appropriate temperature increase time or rate, and then the set temperature is reached. Depending on the dropping method of the monomer component, the initiator, etc., the temperature may be changed over time (temperature increase or decrease) during the polymerization reaction.

The copolymerization time is preferably 30 to 300 minutes. More preferably, it is 60-240 minutes, More preferably, it is 120-180 minutes.
In the present invention, the “polymerization time” refers to the first time when polymerization is carried out while adding a part or all of the monomer to the reactor (reaction kettle) in the palindromic (batch type) polymerization method. From the time when a part or all of the polymerization initiator and a part or all of the monomer are added to the reactor (referred to as polymerization start time) to the time when the whole amount of monomer is added to the reactor (polymerization completed) Until the time). In addition, in the palindromic (batch type) polymerization method, the entire amount of monomer is added to the reactor in advance (referred to as initial charge), and a part or all of the polymerization initiator is added to the reactor (reaction kettle). In the case of polymerization, it is from the time when all or part of the polymerization initiator and all the monomers are first added to the reactor to the time when the entire amount of the polymerization initiator is added to the reactor. . In addition, in the palindromic (batch type) polymerization method, when the total amount of the monomer and the total amount of the polymerization initiator are added to the reactor in advance and the polymerization is performed by means such as heating, an exothermic (polymerization) This is the time when heat generation is observed. Moreover, when superposing | polymerizing by a continuous type, the time which has stayed in the reactor is said.

  The pressure in the reaction system in the copolymerization method may be any of normal pressure (atmospheric pressure), reduced pressure, and increased pressure, but in terms of the molecular weight of the resulting copolymer, The reaction system is preferably sealed and the reaction is carried out under pressure. Moreover, it is preferable to carry out under a normal pressure (atmospheric pressure) at the point of equipment, such as a pressurization apparatus, a pressure reduction apparatus, a pressure-resistant reaction container, and piping. The atmosphere in the reaction system may be an air atmosphere, but is preferably an inert atmosphere. For example, the inside of the system is preferably replaced with an inert gas such as nitrogen before the start of polymerization.

  The pH during the polymerization in the copolymerization is preferably acidic. In particular, when persulfate and bisulfite (salt) are used in combination as the initiator, it is preferably carried out under acidic conditions. By carrying out under acidic conditions, the increase in the viscosity of the aqueous solution of the polymerization reaction system can be suppressed, and the copolymer can be produced satisfactorily. In addition, since the polymerization reaction can proceed under high concentration conditions, the production efficiency can be greatly increased, and the final solid content concentration can be high concentration polymerization of 40% or more, and the residual contained A monomer having a total monomer concentration of 15000 ppm or less can be obtained. Furthermore, the polymerizability of the ether bond-containing monomer can be improved.

  As said acidic condition, it is preferable that pH at 25 degreeC of the reaction solution in superposition | polymerization is 1-6. More preferably, it is 5 or less, More preferably, it is 3 or less. The copolymer obtained by the above copolymerization method may be used in a neutralized state according to the pH at the end of the polymerization, but if necessary, further neutralized with an alkaline substance (both in the neutralization step). Say). As the alkaline substance, it is preferable to use inorganic salts such as hydroxides, chlorides and carbonates of monovalent metals and divalent metals; ammonia; organic ammonium (organic amine) and the like.

  The neutralization rate at the time of copolymerization can be appropriately changed depending on the initiator. For example, when persulfate and bisulfite (salt) are used in combination, if the monomer can form a salt, the neutralization rate of the carboxyl group-containing monomer is set to 0 to 60 mol%. It is preferable to perform copolymerization of monomer components. The neutralization rate of the monomer is represented by mol% of the monomer forming the salt when the total number of moles of the monomer is 100 mol%. If the neutralization rate of the monomer exceeds 60 mol%, the polymerization rate in the copolymerization step does not increase, and the molecular weight of the resulting copolymer may decrease, or the production efficiency may decrease. More preferably, it is 50 mol% or less, more preferably 40 mol% or less, particularly preferably 30 mol% or less, more particularly preferably 20 mol% or less, and most preferably 10 mol%. It is as follows.

  As a method for carrying out copolymerization with the neutralization rate of the above monomer being 0 to 60 mol%, for example, all acid group-containing monomers (carboxyl group-containing monomers, etc.) are not neutralized with acid type When neutralizing the acid group-containing monomer into a salt form such as sodium salt or ammonium salt using an alkaline substance, the neutralization rate is 0 to 60 mol%. A method of subjecting the product to copolymerization is preferred.

  The production method of the present invention usually includes a polymerization step as an essential step. In addition, the neutralization process, the refinement | purification process, etc. may be included.

  The carboxyl group-containing copolymer (or polymer composition) is suitably used as a deinking agent, as well as a water treatment agent, fiber treatment agent, dispersant, detergent builder (or detergent composition), scale inhibitor. (Scale inhibitor), metal ion sealing agent, thickener, various binders, emulsifiers, skin care agents, hair care agents and the like. The detergent builder can be used by being added to clothing, tableware, dwelling, hair, body, toothpaste, and automobile.

<Deinking agent>
The carboxyl group-containing copolymer (or polymer composition) of the present invention can be used as it is as a deinking agent. The deinking agent according to the present invention includes various commonly used agents as required, specifically, for example, alkaline agents such as sodium hydroxide, sodium silicate, sodium carbonate; hydrogen peroxide, Bleaching agents such as sodium hypochlorite and hydrosulfite; chelating agents such as ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA); hydrogen peroxide stabilizers, foaming agents, pitch control agents, dissociation accelerators, or Although it can be used in combination with a known deinking agent, it is not particularly limited. Examples of known deinking agents that can be used in combination with the deinking agent according to the present invention include, for example, higher fatty acid soaps, anionic surfactants, and various nonionic surfactants. However, it is not particularly limited. In addition, in the known deinking process using both a nonionic surfactant and a cationic compound, the deinking agent according to the present invention is used in combination as long as there is no particular problem in performing the deinking process. can do.

  The content of the carboxyl group-containing copolymer of the present invention in the deinking agent according to the present invention is not particularly limited, but is more preferably in the range of 1% by weight to 100% by weight, and 2% by weight to 100%. More preferably within the range of wt%, particularly preferably within the range of 10 wt% to 100 wt%, and most preferably within the range of 20 wt% to 100 wt%. In addition, the amount of the above-mentioned various drugs that can be used in combination with the deinking agent according to the present invention and known deinking agents may be within a range that does not hinder the effects of the deinking agent according to the present invention, It is not particularly limited.

  The deinking treatment method using the deinking agent according to the present invention is not particularly limited, and a known general method, for example, a cleaning method or a flotation method, or a compromise between the cleaning method and the flotation method. Laws can be adopted. More specifically, for example, in the deinking process, the pulp slurry is generally crushed in water to obtain a pulp slurry by pulverizing waste paper (printed waste paper), and the pulp slurry is allowed to stand for a predetermined time after the pulverization process. It comprises at least an aging step for aging, a removing step for removing ink by removing it from the pulp (fiber), and a washing step for filtering and washing the pulp slurry from which the ink has been removed. Each of these steps is repeated two or more times if necessary, depending on the printing technique, the composition and amount of ink (oil-based ink), the properties of used paper, and the like. In addition to the above steps, a dehydration step, a screen step, a dispersion step, etc., which are usually performed in the deinking process, can also be performed.

  Specific examples of the pulp forming the used paper include high yield pulp such as mechanical pulp (MP) and chemical mechanical pulp (CGP); deinked pulp (DIP); soda pulp (AP ) And kraft pulp (KP), etc .; wood pulp such as, but not limited to.

  Examples of the crusher (disintegrator) used in the crushing step include a pulper, a refiner, and a kneader. Although the pulp density | concentration in a pulp slurry is not specifically limited, The inside of the range of 3 weight%-25 weight% is suitable. The temperature of the pulp slurry is preferably in the range of 20 ° C to 70 ° C. The pH of the pulp slurry is preferably in the range of 7.5 to 11.5, and optimally in the range of 8.0 to 11.5.

  The pulp concentration in the aging step is not particularly limited, but is preferably in the range of 10% by weight to 30% by weight. The temperature of the pulp slurry is preferably in the range of 30 ° C to 80 ° C. The aging time of the pulp slurry is not particularly limited, but 1 hour or more is preferable.

  Although the pulp density | concentration in a removal process is not specifically limited, The inside of the range of 0.5 weight%-1.5 weight% is suitable. The temperature of the pulp slurry is preferably in the range of 20 ° C to 50 ° C. As the removal process, a flotation process is preferable. The method for forming bubbles in the flotation process is not particularly limited.

  The calcium ion concentration of water used in the deinking treatment is not particularly limited, and is generally within a range of 10 ppm to 400 ppm, more preferably within a range of 100 ppm to 250 ppm, which is a concentration exhibited by industrial water or tap water. If it is enough. If the calcium ion concentration of water is within the above range, fine pulp is adsorbed by a larger pulp, and thus regenerated pulp can be obtained with good yield. Further, reattachment of the ink to the pulp can be suppressed. The aluminum ion concentration of the water is not particularly limited, and 40 ppm or less, more preferably 25 ppm or less is sufficient. Since the deinking agent according to the present invention has a polyanion structure in which a large number of carboxyl groups are introduced, the calcium ion concentration and the aluminum ion concentration in the pulp slurry can be maintained at appropriate values. The process can be performed more easily.

  The pH of the water used in the deinking process is not particularly limited. The pH of the water can be adjusted using a general acid / base. Since the deinking agent according to the present invention has good dispersibility in pulp slurry, it is excellent in operability.

  The amount of the deinking agent used may be set according to the printing technique, the ink composition and amount, the properties of the wastepaper, etc., and is not particularly limited, but the dry weight of the wastepaper to be deinked (absolutely dry) The weight is more preferably in the range of 0.05% to 10% by weight, and still more preferably in the range of 0.1% to 5% by weight. If the amount used is less than 0.05% by weight, the ink may not be sufficiently removed. On the other hand, even if the amount used is more than 10% by weight, no further effect can be expected, and excess deinking agent is wasted.

<Water treatment agent>
The carboxyl group-containing copolymer (or polymer composition) of the present invention can be used as a water treatment agent. If necessary, the water treatment agent may contain a polymerized phosphate, phosphonate, anticorrosive, slime control agent, and chelating agent as other compounding agents.

  The water treatment agent is useful for scale prevention in a cooling water circulation system, a boiler water circulation system, a seawater desalination apparatus, a pulp digester, a black liquor concentration tank, and the like. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effects.

<Fiber treatment agent>
The carboxyl group-containing copolymer (or polymer composition) of the present invention can be used as a fiber treatment agent. The fiber treatment agent includes at least one selected from the group consisting of a dye, a peroxide and a surfactant, and the carboxyl group-containing copolymer of the present invention.

  The content of the carboxyl group-containing copolymer of the present invention in the fiber treatment agent is preferably 1 to 100% by weight, more preferably 5 to 100% by weight, based on the entire fiber treatment agent. Further, any appropriate water-soluble polymer may be included as long as the performance and effects are not affected.

  Below, the compounding example of the fiber processing agent which is closer to embodiment is shown. This fiber treatment agent can be used in the steps of refining, dyeing, bleaching and soaping in fiber treatment. Examples of dyeing agents, peroxides and surfactants include those usually used for fiber treatment agents.

  The blending ratio of the carboxyl group-containing copolymer of the present invention to at least one selected from the group consisting of a dye, a peroxide, and a surfactant is, for example, the whiteness of the fiber, uneven color, and dyeing tempering degree. For the improvement, at least one selected from the group consisting of a dyeing agent, a peroxide and a surfactant with respect to 1 part by weight of the carboxyl group-containing copolymer of the present invention in terms of pure amount of the fiber treatment agent. It is preferable to use the composition mix | blended in the ratio of 0.1-100 weight part as a fiber processing agent.

  Arbitrary appropriate fiber can be employ | adopted as a fiber which can use the said fiber processing agent. Examples thereof include cellulosic fibers such as cotton and hemp, chemical fibers such as nylon and polyester, animal fibers such as wool and silk, semi-synthetic fibers such as human silk, and woven fabrics and blended products thereof.

When the fiber treatment agent is applied to the refining process, it is preferable to blend the carboxyl group-containing copolymer of the present invention with an alkali agent and a surfactant. When applied to the bleaching step, it is preferable to blend the carboxyl group-containing copolymer of the present invention, a peroxide, and a silicic acid-based agent such as sodium silicate as a decomposition inhibitor for the alkaline bleaching agent.
<Inorganic pigment dispersant>
The carboxyl group-containing copolymer (or polymer composition) of the present invention can be used as an inorganic pigment dispersant. If necessary, the inorganic pigment dispersant may contain condensed phosphoric acid and its salt, phosphonic acid and its salt, and polyvinyl alcohol as other compounding agents.

  The content of the carboxyl group-containing copolymer of the present invention in the inorganic pigment dispersant is preferably 5 to 100% by weight with respect to the whole inorganic pigment dispersant. Further, any appropriate water-soluble polymer may be included as long as it does not affect the performance and effect.

  The inorganic pigment dispersant can exhibit good performance as a dispersant for heavy or light calcium carbonate or clay inorganic pigment used in paper coating. For example, by adding a small amount of an inorganic pigment dispersant to an inorganic pigment and dispersing it in water, high concentration calcium carbonate having low viscosity and high fluidity and good aging stability of their performance. High concentration inorganic pigment slurries such as slurries can be produced.

  When the inorganic pigment dispersant is used as a dispersant for an inorganic pigment, the amount of the inorganic pigment dispersant used is preferably 0.05 to 2.0 parts by weight with respect to 100 parts by weight of the inorganic pigment. When the amount of the inorganic pigment dispersant used is within the above range, a sufficient dispersion effect can be obtained, and an effect commensurate with the addition amount can be obtained, which can be economically advantageous.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by mass” and “%” means “% by mass”.
Moreover, the weight average molecular weight, deinking performance, etc. of the carboxyl group-containing copolymer of the present invention were measured according to the following methods.

<Measurement conditions of weight average molecular weight>
Equipment: Hitachi L-7000 series detector: RI
Column: SHODEX Asahipak GF-310-HQ, GF-710-HQ, GF-1G 7B manufactured by Showa Denko KK
Column temperature: 40 ° C
Flow rate: 0.5 ml / min.
Calibration curve: POLYACRYLIC ACID STANDARD made by Soka Science Co., Ltd.
Eluent: 0.1N sodium acetate / acetonitrile = 3/1 (mass ratio)
<Deinking performance evaluation method (flotation method)>
After waste paper containing offset printing newspaper and magazines in a ratio of 7/3 by weight (newspaper / magazines) is cut into a size of 3 cm × 3 cm and put into a pulp disintegrator, the pulp concentration is 15 A predetermined amount of hot water at 50 ° C. was poured so as to be%. Subsequently, sodium hydroxide and sodium silicate which are alkali agents were added to adjust the pH of water to 10.7. Then, 0.2% of a polymer as a deinking agent with respect to the dry weight (absolute dry weight) of the used paper was added to the pulp disintegrator and then pulverized for 10 minutes to obtain a pulp slurry.
Next, the pulp concentration of the pulp slurry is adjusted to 24% by centrifugal dewatering using an 80 mesh filter cloth, and then sodium hydroxide and sodium silicate are added to the pulp slurry. The pH was adjusted to 11.2.
Subsequently, after adding 0.15% of the deinking agent and 1.5% hydrogen peroxide (bleaching agent) to the pulp slurry based on the dry weight of the waste paper, the pulp slurry was kept at a constant temperature of 50 ° C. Aging treatment was performed in the tank for 2 hours. After aging, the pulp slurry was passed through a kneader twice.

Next, after pouring a predetermined amount of water and adjusting the pulp concentration of the pulp slurry to 1%, a flotation treatment was performed at 35 ° C. for 12 minutes using a Denver-type floatator. After the treatment, the pulp slurry is subjected to centrifugal dehydration using an 80 mesh filter cloth to adjust (concentrate) the pulp concentration of the pulp slurry to 10%, and then a predetermined amount of water is poured to reduce the pulp concentration to 1%. Adjusted (diluted).
A pulp sheet was prepared from this pulp slurry using a TAPPI sheet machine. The whiteness of the obtained pulp sheet was measured by a method according to the method described in JIS P 8123 (hunter whiteness test method) using a colorimetric color difference meter. Further, the number of ink stains of 4 μm or less formed per 1 cm 2 of pulp sheet was determined using an image processing apparatus. It can be determined that the larger the measured value is, and the smaller the number of ink stains, the better the deinking agent is in the deinking effect (ink aggregation performance, etc.).

<Method for measuring solid content of polymer composition>
In a nitrogen atmosphere, the polymer composition (polymer composition 1.0 g + water 3.0 g) was left to dry for 1 hour in an oven heated to 130 ° C. From the weight change before and after drying, the solid content (%) and the volatile component (%) were calculated.

<Example 1>
A glass separable flask with a capacity of 2000 mL equipped with a reflux condenser and a stirrer (paddle blade) was charged with 128.6 g of pure water and 0.0158 g of Mole salt, and the temperature was raised to 90 ° C. while stirring to polymerize the reaction. It was a system. Next, in a polymerization reaction system maintained at 90 ° C. with stirring, 270.0 g of an 80% aqueous acrylic acid solution (hereinafter also referred to as “80% AA”), allyl n-butyl ether (hereinafter also referred to as “ABE”). .) 24.0 g, 15% sodium persulfate aqueous solution (hereinafter also referred to as “15% NaPS”) 64.2 g, and 35% sodium hydrogen sulfite aqueous solution (hereinafter also referred to as “35% SBS”) 36.7 g Were dropped from separate nozzles. The dropping time of each solution was 180 minutes for 80% AA, 150 minutes for ABE, 190 minutes for 15% NaPS, and 175 minutes for 35% SBS. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously.
After the completion of the dropwise addition of 80% AA, the reaction solution was kept at 90 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, 225.0 g of a 48% sodium hydroxide aqueous solution (hereinafter also referred to as “48% NaOH”) was gradually added dropwise while stirring and allowing the polymerization reaction liquid to cool, thereby neutralizing the polymerization reaction liquid.
Thus, an aqueous solution (polymer composition 1 of the present invention) of the polymer (1) as a carboxyl group-containing copolymer of the present invention having a solid content concentration of 45% and a weight average molecular weight of 17,000 was obtained.

<Example 2>
A glass separable flask with a capacity of 2000 mL equipped with a reflux condenser and a stirrer (paddle blade) was charged with 129.7 g of pure water and 0.0158 g of Mole salt, and the temperature was raised to 90 ° C. while stirring to polymerize the reaction. It was a system. Next, 270.0 g of 80% AA, 24.0 g of allyl n octyl ether (hereinafter also referred to as “AOE”), 62.8 g of 15% NaPS, and 35 in a polymerization reaction system maintained at 90 ° C. with stirring. % SBS 35.9 g was dropped from separate nozzles. The dropping time of each solution was 180 minutes for 80% AA, 120 minutes for AOE, 190 minutes for 15% NaPS, and 175 minutes for 35% SBS. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously.
After the completion of the dropwise addition of 80% AA, the reaction solution was kept at 90 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, while stirring and allowing the polymerization reaction liquid to cool, 225.0 g of 48% NaOH was gradually added dropwise to neutralize the polymerization reaction liquid.
Thus, an aqueous solution (polymer composition 2 of the present invention) of the polymer (2) as a carboxyl group-containing copolymer of the present invention having a solid content concentration of 45% and a weight average molecular weight of 14,000 was obtained.

<Example 3>
A glass separable flask with a capacity of 2000 mL equipped with a reflux condenser and a stirrer (paddle blade) was charged with 101.8 g of pure water and 0.0160 g of Mole salt, and the temperature was raised to 70 ° C. while stirring to polymerize the reaction. It was a system. Next, in a polymerization reaction system maintained at 70 ° C. with stirring, 270.0 g of 80% AA, 24.0 g of n-butyl vinyl ether (hereinafter also referred to as “BVE”), 108.0 g of 15% NaPS, and 35% 27.8 g of SBS was dropped from separate nozzles. The dropping time of each solution was 180 minutes for 80% AA, 150 minutes for BVE, 190 minutes for 15% NaPS, and 175 minutes for 35% SBS. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously.
After the completion of the dropwise addition of 80% AA, the reaction solution was kept at 70 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, while stirring and allowing the polymerization reaction liquid to cool, 225.0 g of 48% NaOH was gradually added dropwise to neutralize the polymerization reaction liquid.
Thus, an aqueous solution (polymer composition 3 of the present invention) of the polymer (3) as a carboxyl group-containing copolymer of the present invention having a solid content concentration of 45% and a weight average molecular weight of 10,000 was obtained.

<Comparative Example 1>
A glass separable flask having a capacity of 2000 mL equipped with a reflux condenser and a stirrer (paddle blade) was charged with 128.3 g of pure water and 0.0158 g of Mole salt, and the temperature was raised to 90 ° C. while stirring to polymerize the reaction. It was a system. Next, 270.0 g of 80% AA, 24.0 g of styrene (hereinafter also referred to as “St”), 64.6 g of 15% NaPS, and 35% SBS in a polymerization reaction system maintained at 90 ° C. with stirring. 9 g was dropped from each separate nozzle. The dropping time of each solution was 180 minutes for 80% AA, 150 minutes for St, 190 minutes for 15% NaPS, and 175 minutes for 35% SBS. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously.
After the completion of the dropwise addition of 80% AA, the reaction solution was kept at 90 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, while stirring and allowing the polymerization reaction liquid to cool, 225.0 g of 48% NaOH was gradually added dropwise to neutralize the polymerization reaction liquid.
In this way, an aqueous solution of the comparative polymer (1) having a solid content concentration of 45% and a weight average molecular weight of 16,000 (the comparative polymer composition 1 of the present invention) was obtained.

<Comparative Example 2>
A glass separable flask with a capacity of 2000 mL equipped with a reflux condenser and a stirrer (paddle blade) was charged with 129.0 g of pure water and 0.0158 g of Mole salt, and the temperature was raised to 90 ° C. while stirring to polymerize the reaction. It was a system. Next, in a polymerization reaction system maintained at 90 ° C. with stirring, 270.0 g of 80% AA, 24.0 g of n-butyl acrylate (hereinafter also referred to as “BA”), 63.8 g of 15% NaPS, and 35% 36.4 g of SBS was dropped from each separate nozzle. The dropping time of each solution was 180 minutes for 80% AA, 160 minutes for St, 190 minutes for 15% NaPS, and 175 minutes for 35% SBS. Moreover, the dropping rate of each solution was made constant, and each solution was dropped continuously.
After the completion of the dropwise addition of 80% AA, the reaction solution was kept at 90 ° C. (ripening) for 30 minutes to complete the polymerization. After completion of the polymerization, while stirring and allowing the polymerization reaction liquid to cool, 225.0 g of 48% NaOH was gradually added dropwise to neutralize the polymerization reaction liquid.
In this way, an aqueous solution of the comparative polymer (2) having a solid content concentration of 45% and 13,000 (the comparative polymer composition 2 of the present invention) was obtained.

Claims (2)

A structural unit (a) derived from an ether bond-containing monomer (A) represented by the following general formula (1) of 1% by mass to 50% by mass,
A structural unit (b) derived from 50% by mass to 99% by mass of the carboxyl group-containing monomer (B),
A carboxyl group-containing copolymer having as an essential structural unit.

In the general formula (1), in the formula, R ₁ represents a hydrogen atom or a CH ₃ group, R ₂ represents a CH ₂ group or a CH ₂ CH ₂ group, and R ₃ has 1 to 20 carbon atoms. A substituted or unsubstituted alkyl group, an aryl group, or an alkenyl group is represented. 1% by mass or more and 50% by mass or less of an ether bond-containing monomer (A) represented by the following general formula (1),
50% by mass or more and 99% by mass or less of the carboxyl group-containing monomer (B),
Including a step of polymerizing as essential,
A method for producing a carboxyl group-containing copolymer.

In the general formula (1), in the formula, R ₁ represents a hydrogen atom or a CH ₃ group, R ₂ represents a CH ₂ group or a CH ₂ CH ₂ group, and R ₃ has 1 to 20 carbon atoms. A substituted or unsubstituted alkyl group, an aryl group, or an alkenyl group is represented.