JP6914588B2 - Carboxyl group-containing copolymer - Google Patents

Description

The present invention relates to a carboxyl group-containing copolymer. More specifically, the present invention relates to a carboxyl group-containing copolymer useful for surface coating agents, coating agents, paints and the like.

Carboxyl group-containing polymers are useful polymers used in various industrial fields, such as cement dispersants, pigment dispersants, water treatment agents (anti-adhesion agents for scale components), detergents, binders, etc. Widely used in applications such as surface coating agents, coating agents, and paints. In these markets, polymers with higher performance are required.

As a method for meeting such a demand, for example, Patent Document 1 describes a binder containing a polymer having a hydroxyl group, wherein the polymer contains a structural unit derived from an unsaturated carboxylic acid-based monomer and a structural unit. The ratio of molar equivalents of the carboxyl group (including the salt of the carboxyl group and the anhydride of the carboxyl group) contained in the polymer to the hydroxyl group, which contains a predetermined structural unit, is 1: 0.01 to 1: 3. There is disclosed a binder in which 0 to 35 mol% of the carboxyl groups contained in the polymer are neutralized.
Patent Document 2 describes a method for producing an acrylic acid-based polymer composition, wherein 0.5 to 4.5 parts of a hypophosphite compound is added to 100 parts by mass of all the constituent monomer units of the polymer. Acrylic acid-based polymer composition used and characterized in that 1 to 50% by mass of the total amount of the hypophosphite compound is charged into the reactor before the monomer is supplied and the polymerization temperature is 68 to 82 ° C. A method of manufacturing a product is disclosed.

Further, a technique for improving the heat resistance of a polymer has been developed by using a phosphorus atom-containing compound as a chain transfer agent. For example, Patent Document 3 contains an N-vinyllactam-based polymer and a monocarboxylic acid (salt), and the N-vinyllactam-based polymer has a K value of 10 or more and 40 or less, and has a main chain. N-vinyl, which contains a phosphorus atom and has a monocarboxylic acid (salt) content of 0.05% by mass or more and 2% by mass or less with respect to the solid content of the N-vinyllactam-based polymer composition. A lactam-based polymer composition is disclosed.

JP 2015-174981 Japanese Patent No. 5915750 Japanese Unexamined Patent Publication No. 2013-133351

As described above, various carboxyl group-containing (co) polymers and production methods are disclosed, and the carboxyl group-containing polymer obtained by using a phosphorus atom-containing compound can be suitably used for applications requiring heat resistance. can. Among the applications that require heat resistance, there are also applications that require further water resistance. However, the conventional carboxyl group-containing polymer is not sufficient in water resistance.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a carboxyl group-containing copolymer having excellent heat resistance and water resistance.

The present inventor has made various studies on carboxyl group-containing polymers, and found that polymers having a structural unit derived from an unsaturated carboxylic acid-based monomer and a structural unit derived from an unsaturated monomer having an oxyalkylene group were further found. We found that a copolymer having a phosphorus atom-containing group in the molecule and having a weight average molecular weight of 10,000 or more is excellent in heat resistance and water resistance, and came up with the idea that the above-mentioned problems can be solved brilliantly. However, the present invention has been reached.

That is, in the present invention, the structural unit (a) derived from the unsaturated carboxylic acid monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles of groups added and is a number from 2 to 80. X represents a number from 0 to 2. y represents a 0 or 1 polyalkylene glycol-based monomer (representing 0 or 1). A carboxyl group-containing copolymer having a structural unit (b) derived from B), wherein the copolymer has a phosphorus atom-containing group in the molecule and has a weight average molecular weight of 10,000 or more. It is a containing copolymer.

The weight average molecular weight is preferably 150,000 or less.
It is preferable that x in the above formula (1) is 2 and y is 0.
^{R 3} in the above formula (1) is preferably a methyl group.

The phosphorus atom-containing group preferably has a structure derived from hypophosphorous acid (salt).
In the above copolymer, the ratio of the structural unit (a) is preferably 10 to 90% by mass with respect to 100% by mass of all the structural units.
The present invention is also a carboxyl group-containing copolymer composition containing a carboxyl group-containing copolymer and a cross-linking agent.
The present invention further comprises a method for producing a carboxyl group-containing copolymer, wherein the production method comprises an unsaturated carboxylic acid-based monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of added moles of a group and is a number from 2 to 80. X represents a number from 0 to 2. y represents 0 or 1) to form a structural unit (b). A step of polymerizing a monomer component containing a polyalkylene glycol-based monomer (B) with a chain transfer agent containing a phosphorus atom-containing compound is included, and the weight average molecular weight of the carboxyl group-containing copolymer is 1. It is also a method for producing a carboxyl group-containing copolymer having more than 10,000.

The carboxyl group-containing copolymer of the present invention has the above-mentioned structure and is excellent in heat resistance and water resistance, so that it can be suitably used for various purposes. Above all, it can be suitably used for applications such as surface coating agents, coating agents, and paints.

Hereinafter, preferred embodiments of the present invention will be specifically described, but the present invention is not limited to the following description, and can be appropriately modified and applied without changing the gist of the present invention. A form in which two or three or more of the individual preferred forms of the present invention described below are combined also falls under the preferred form of the present invention.

<Carboxyl group-containing copolymer>
The carboxyl group-containing copolymer of the present invention (hereinafter, also simply referred to as the copolymer of the present invention) has a structural unit (a) derived from an unsaturated carboxylic acid-based monomer (A) and the above formula (1). It has a structural unit (b) derived from the (poly) alkylene glycol-based monomer (B) represented, and further has a phosphorus atom-containing group in the molecule.
Since the carboxyl group-containing copolymer has a phosphorus atom-containing group in the molecule, decomposition of the polymer when the polymer is heated can be suppressed, and the color resistance (heat-resistant yellowing) is excellent.

The carboxyl group-containing copolymer is not particularly limited as long as it has a phosphorus atom-containing group in the molecule, but it is preferable that the carboxyl group-containing copolymer has a phosphorus atom-containing group at the end of the main chain (molecular end).
The phosphorus atom-containing group contained in the carboxyl group-containing copolymer can be analyzed by, for example, ³¹ P-NMR measurement.

The phosphorus atom-containing group is not particularly limited as long as it is a group containing a phosphorus atom, but is preferably a reducing group. Examples of the reducing phosphorus atom-containing group include hypophosphorous acid (salt) group and phosphorous acid (salt) group. More preferably, it is a hypophosphorous acid (salt) group.
The hypophosphorous acid (salt) group means a hypophosphorous acid group or a salt thereof, and the phosphorous acid (salt) group means a phosphorous acid group or a salt thereof.

Examples of the salt include metal salts, ammonium salts, organic amine salts and the like, and more specifically, metal salts include alkali metal salts such as sodium salt and potassium salt; magnesium salt, calcium salt, strontium salt and the like. Alkaline earth metal salts such as barium salt; salts such as aluminum salt and iron salt can be mentioned. Examples of the organic amine salt include alkanolamine salts such as monoethanolamine salt, diethanolamine salt and triethanolamine salt; alkylamine salts such as monoethylamine salt, diethylamine salt and triethylamine salt; morpholinic salt and the like. Among these, sodium salt and potassium salt are preferable as the salt.

The carboxyl group-containing copolymer has a weight average molecular weight of 10,000 or more.
From the viewpoint of the motility of the copolymer when cross-linking the copolymer, the weight average molecular weight of the copolymer is preferably 150,000 or less. Further, if the weight average molecular weight is 15,000 or more, the copolymer of the present invention is more excellent in water resistance.
The weight average molecular weight is more preferably 18,000 to 120,000, further preferably 20,000 to 110,000, and particularly preferably 25,000 to 100,000.
The weight average molecular weight can be measured by the method described in Examples.

In the above copolymer, the ratio of the structural unit (a) is preferably 10 to 90% by mass with respect to 100% by mass of all the structural units. As a result, when the copolymer is crosslinked using a crosslinking agent, a crosslinked structure can be formed more efficiently.
The ratio of the structural unit (a) is more preferably 15 to 80% by mass, still more preferably 20 to 70% by mass.
When the carboxyl group of the structural unit (a) is of the salt type, its mass shall be calculated as the structural unit of the corresponding acid type. For example, in the case of a structure derived from sodium (meth) acrylic acid, the mass ratio is calculated as the structure derived from (meth) acrylic acid. Similarly, when the monomer is a salt type, the mass of other monomers described later is calculated as an acid type monomer.

The copolymer preferably has a structural unit (b) ratio of 10 to 90% by mass with respect to 100% by mass of all structural units.
It is more preferably 20 to 85% by mass, and even more preferably 30 to 80% by mass.

The copolymer has a structural unit (e) derived from an unsaturated carboxylic acid-based monomer (A) and a other monomer (E) other than the polyalkylene glycol-based monomer (B). May be good.
The ratio of the structural unit (e) in the copolymer is preferably 0 to 30% by mass with respect to 100% by mass of all structural units.
It is more preferably 0 to 20% by mass, further preferably 0 to 10% by mass, and most preferably 0% by mass.

<Unsaturated carboxylic acid-based monomer (A)>
The unsaturated carboxylic acid-based monomer (A) is not particularly limited as long as it has a carboxyl group and an ethylenically unsaturated hydrocarbon group (unsaturated group), but is an unsaturated monocarboxylic acid-based monomer. And unsaturated dicarboxylic acid-based monomers.
The unsaturated monocarboxylic acid-based monomer may be a monomer having one unsaturated group and one group capable of forming a carboanion in the molecule, and may be, for example, (meth) acrylic acid or crotonic acid. , Isocrotonic acid, tigric acid, 3-methylcrotonic acid, 2-methyl-2-pentenoic acid, α-hydroxyacrylic acid, etc .; these monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts; A half ester of a saturated dicarboxylic acid-based monomer and an alcohol having 1 to 22 carbon atoms or a glycol having 2 to 4 carbon atoms; a half amide of an unsaturated dicarboxylic acid-based monomer and an amine having 1 to 22 carbon atoms, etc. Can be mentioned.
The unsaturated dicarboxylic acid-based monomer may be a monomer having one unsaturated group and two groups capable of forming a carboanion in the molecule, and may be maleic acid, itaconic acid, mesaconic acid, or citraconic acid. Examples thereof include acids, fumaric acids and the like, their monovalent metal salts, divalent metal salts, ammonium salts, organic amine salts and the like, and their anhydrides.
As the unsaturated carboxylic acid-based monomer (A), (meth) acrylic acid (salt), maleic acid (salt) or maleic anhydride is preferable. More preferably, it is (meth) acrylic acid (salt).

<Polyalkylene glycol-based monomer (B)>
The polyalkylene glycol-based monomer (B) has the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles added of a group and is a number from 2 to 80. X represents a number from 0 to 2. y represents 0 or 1) to form a structural unit (b). The following equation (2);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles of groups added, and is a number from 2 to 80. X represents a number from 0 to 2. y represents a monomer represented by 0 or 1). ..

^{R 1} , R ² and R ³ in the above formula (1) or (2) are the same or different, and are hydrogen atoms or methyl groups. Preferably, R ¹ and R ² are hydrogen atoms, and R ³ is a hydrogen atom or a methyl group. More preferably, R ³ is a methyl group.

In the above formula (1) or (2), AO represents an oxyalkylene group "same or different", which means that all n oxyalkylene groups of AO present in the polyalkylene glycol are the same. It means that it may or may not be different.
In the above formula (1) or (2), the oxyalkylene group represented by AO is an alkylene oxide adduct, and examples of such alkylene oxides include ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, and 1-butene. Examples thereof include alkylene oxides having 2 to 8 carbon atoms such as oxides, 2-butene oxides and styrene oxides. More preferably, it is an alkylene oxide having 2 to 4 carbon atoms such as ethylene oxide, propylene oxide and butylene oxide, and even more preferably ethylene oxide and propylene oxide.
When the polyalkylene glycol is any two or more types of alkylene oxide adducts selected from ethylene oxide, propylene oxide, butylene oxide, styrene oxide and the like, any of random addition, block addition, alternating addition and the like. It may be in the form. In order to secure a balance between hydrophilicity and hydrophobicity, it is preferable to have an oxyethylene group as an essential component as the oxyalkylene group in the polyalkylene glycol, and more preferably 50 mol% or more is an oxyethylene group. , 90 mol% or more is more preferably an oxyethylene group.

In the above formula (1) or (2), n represents the average number of moles of oxyalkylene group added, and is 2 to 80. It is preferably 4 to 70, more preferably 6 to 60, and even more preferably 8 to 55.

In the above formula (1) or (2), x represents a number from 0 to 2, y represents 0 or 1, but y is preferably 0. When y is 0, x is preferably 1 or 2. In this case, R ³ is preferably a methyl group. x is more preferably 2.

Examples of the polyalkylene glycol-based monomer (B) include polyalkylene glycol (meth) acrylates having 2 to 80 moles of alkylene glycol added, such as diethylene glycol (meth) acrylate; vinyl alcohol, allyl alcohol, and metalyl alcohol. 3-Methyl-3-butene-1-ol (isoprenol), 3-methyl-2-butene-1-ol, 2-methyl-3-butene-1-ol, 2-methyl-2-buten-1-ol Examples thereof include compounds in which 2 to 80 mol of alkylene oxide is added to an unsaturated alcohol having 2 to 8 carbon atoms. Among these, polyethylene glycol (meth) acrylate; allyl alcohol, methallyl alcohol, 3-methyl-3-butene-1-ol with alkylene oxide added is preferable. More preferably, it is obtained by adding an alkylene oxide to 3-methyl-3-butene-1-ol.

The copolymer of the present invention has a structural unit (e) derived from a monomer (E) other than the unsaturated carboxylic acid-based monomer (A) and the polyalkylene glycol-based monomer (B). May be.
The other monomer (E) is not particularly limited as long as it can be copolymerized with the monomer (A) or (B), but 3- (meth) allyloxy-2-hydroxypropanesulfonic acid, 2- ( Meta) allyloxyethylene sulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, p-styrenesulfonic acid, α-methyl-p-styrenesulfonic acid, vinylsulfonic acid, vinylsulfamic acid, (meth) allylsulfonic acid, Isoprene sulfonic acid, 4- (allyloxy) benzene sulfonic acid, 1-methyl-2-propen-1-sulfonic acid, 1,1-dimethyl-2-propen-1-sulfonic acid, 3-butene-1-sulfonic acid, 1-buten-3-sulfonic acid, 2-acrylamide-1-methylpropanesulfonic acid, 2-acrylamidepropanesulfonic acid, 2-acrylamide-n-butanesulfonic acid, 2-acrylamide-2-phenylpropanesulfonic acid, 2- Unsaturated sulfonic acids such as ((meth) acryloyloxy) ethanesulfonic acid and salts thereof; hydroxyl group-containing (meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; 3- (meth) allyloxy- Hydroxyl group-containing ethers such as 1,2-dihydroxypropane and 1-allyloxy-3-butoxypropan-2-ol; N-vinyllactam-based monomers such as N-vinylpyrrolidone; methyl (meth) acrylate, (meth). ) Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, iso (meth) acrylate (Meta) acrylate esters such as -nonyl, dodecyl (meth) acrylate, stearyl (meth) acrylate; (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth) acrylamide, N, N -N-substituted or unsubstituted (meth) acrylamide such as dimethyl (meth) acrylamide; vinyl aryl monomer such as styrene, α-methylstyrene, vinyltoluene, inden, vinylnaphthalene, phenylmaleimide, vinylaniline; ethylene, propylene , Alkens such as butadiene, isobutylene, octene; vinyl carboxylates such as vinyl acetate and vinyl propionate; vinyl such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether Luthers; vinylethylene carbonate and its derivatives; N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, vinylpyridine, vinylimidazole and salts thereof or quaternized products thereof, etc. Unsaturated amines; vinyl cyanide-based monomers such as acrylonitrile and methacrylonitrile can be mentioned.

<Production method of carboxyl group-containing copolymer>
The production of the copolymer of the present invention is not particularly limited, but it can be produced by polymerizing the monomer components, and specific examples and preferable examples of the monomer components, and a preferable ratio of each monomer. Is as described above.
The above-mentioned method for producing a copolymer comprises a monomer component containing an unsaturated carboxylic acid-based monomer (A) and a polyalkylene glycol-based monomer (B), and a chain transfer agent containing a phosphorus atom-containing compound. It is preferable to include a step of polymerizing using the compound (hereinafter, also referred to as “polymerization step”).
A method for producing such a carboxyl group-containing copolymer is also one of the present inventions.
That is, it is a method for producing a carboxyl group-containing copolymer, and the above-mentioned production method is an unsaturated carboxylic acid-based monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of added moles of a group and is a number from 2 to 80. X represents a number from 0 to 2. y represents 0 or 1) to form a structural unit (b). A step of polymerizing a monomer component containing a polyalkylene glycol-based monomer (B) with a chain transfer agent containing a phosphorus atom-containing compound is included, and the weight average molecular weight of the carboxyl group-containing copolymer is 1. A method for producing a carboxyl group-containing copolymer of 10,000 or more is also one of the present inventions.

The method for initiating the polymerization of the monomer component in the above polymerization step is not particularly limited, but for example, a method for adding a polymerization initiator, a method for irradiating UV, a method for applying heat, and a method in the presence of a light initiator. Examples thereof include a method of irradiating light.
It is preferable to use a polymerization initiator in the above polymerization step.
Examples of the polymerization initiator include hydrogen peroxide; persulfates such as sodium persulfate, potassium persulfate, and ammonium persulfate; dimethyl 2,2'-azobis (2-methylpropionate), 2,2'-. Azobis (isobutyronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride (2,2'-azobis-2-amidinopropane dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2- (2- (2-) Imidazoline-2-yl) propane] Azobisisobutyates such as dihydrochloride, 2,2'-azobis (1-imino-1-pyrrolidino-2-methylpropane) dihydrochloride; benzoyl peroxide, lauroyl peroxide, excess Organic peroxides such as acetic acid, di-t-butyl peroxide and cumene hydroperoxide; a combination of an oxidizing agent and a reducing agent such as ascorbic acid and hydrogen peroxide, persulfate and metal salt to generate radicals. An oxidation-reduction type initiator or the like is suitable. Among these polymerization initiators, hydrogen peroxide, persulfates, and azo compounds are preferable, and persulfates are more preferable, because the residual monomers tend to decrease. These polymerization initiators may be used alone or in the form of a mixture of two or more.

The amount of the polymerization initiator used is the total amount of the monomers used (unsaturated carboxylic acid-based monomer (A), polyalkylene glycol-based monomer (B) and other monomers (E)). It is preferably 0.1 g or more and 10 g or less, more preferably 0.2 g or more and 8 g or less, and further preferably 0.5 g or more and 7 g or less with respect to 1 mol. ..

In the above polymerization step, it is preferable to use a chain transfer agent.
Examples of the chain transfer agent include hypophosphorous acid (salts) such as hypophosphorous acid and sodium hypophosphate (including hydrates thereof), and phosphorous acid (salts) such as phosphorous acid and sodium phosphite. It is preferable to use a phosphorus atom-containing compound such as), and a phosphorus atom-containing group is introduced into the main chain terminal of the copolymer by polymerizing the monomer component in the presence of these chain transfer agents. Can be done. When hypophosphorous acid (salt) or phosphorous acid (salt) is used as the chain transfer agent, the polymerization step can be carried out in an aqueous solvent.
Among these, it is more preferable to use hypophosphorous acid (salt).

Further, in the above polymerization step, a chain transfer agent other than the phosphorus atom-containing compound can be used in combination. Other chain transfer agents include thiol-based chain transfer agents such as mercaptoethanol and mercaptopropionic acid; halides such as carbon tetrachloride and methylene chloride; secondary alcohols such as isopropyl alcohol and glycerin; sulfites such as sodium sulfite. (Salt); Dithionite (salt) such as sodium hydrogen sulfite; Sodium dithionite (salt) such as sodium bisulfite; Pyro sulfite (salt) such as potassium pyrosulfite, and the like. The other chain transfer agents may be used alone or in combination of two or more.

When a carboxyl group-containing copolymer is produced using a thiol-based chain transfer agent as the chain transfer agent, the thiol compound remains in the obtained polymer. When such a carboxyl group-containing copolymer (composition) is crosslinked using an isocyanate-based crosslinking agent, the amount of crosslinks is small because the thiol group has higher reactivity with isocyanate than the hydroxyl group of the polymer. Will be. On the other hand, when a carboxyl group-containing copolymer is produced using a phosphorus atom-containing compound without using a thiol-based chain transfer agent, the thiol compound does not remain in the polymer, and therefore an isocyanate-based crosslinker is used. Even when a cross-linking agent is used, a cross-linked structure can be efficiently formed. That is, it is preferable to produce a carboxyl group-containing copolymer using a phosphorus atom-containing compound because the types of cross-linking agents that can be preferably used are widened. Further, when a thiol-based chain transfer agent is used as the chain transfer agent, the thiol compound remaining in the polymer may cause an odor. On the other hand, since the phosphorus atom-containing compound does not have a problem of odor, it is preferable from the viewpoint of expanding the applicable applications of the obtained copolymer.

The amount of the chain transfer agent used in the production of the copolymer of the present invention is preferably 0.01 g or more and 10 g or less with respect to 1 mol of the monomer (all monomers) used, and is 0. More preferably, it is 1 g or more and 8 g or less. It is more preferably 6 g or less, still more preferably 5 g or less, and particularly preferably 4 g or less.

When a solvent is used in the above polymerization step, an aqueous solvent is preferable as the solvent. Examples of the aqueous solvent include water, methyl alcohol, ethyl alcohol, isopropyl alcohol (2-propanol), n-butyl alcohol, alcohols such as diethylene glycol, glycol, glycerin, polyethylene glycol and the like, and water is preferable. ..
In order to improve the solubility of the monomer in the solvent, any suitable organic solvent may be appropriately added as long as it does not adversely affect the polymerization. Examples of such an organic solvent 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, diethyl ether and dioxane; and amides such as dimethyl formaldehyde. Kind and the like. Only one kind of these solvents may be used, or two or more kinds may be used.
The amount of the solvent used is preferably 40 to 300% by mass with respect to 100% by mass of the monomer.

In the above polymerization step, the polymerization temperature is not particularly limited, but it is more preferable if it is in the range of 20 ° C. to 110 ° C. because the polymerization rate is further improved. It is more preferably 50 ° C. to 108 ° C., even more preferably 60 ° C. to 106 ° C., particularly preferably 65 ° C. to 103 ° C., and most preferably 70 ° C. to 98 ° C.
Further, in the polymerization step, at least 50% of the time from the start of the polymerization reaction to the end of the addition of the monomer component, the chain transfer agent and the polymerization initiator, which is the latest to finish the addition, is at least 50%. The reaction temperature is preferably in the range of 20 ° C. to 110 ° C.

In the polymerization step, the reaction time depends on the reaction temperature, the type (property) of the monomer component, the polymerization initiator, the solvent, etc., the combination, the amount used, etc. so that the polymerization reaction is completed. It may be set appropriately.

The above-mentioned method for producing a copolymer preferably includes a step of aging the copolymer after the polymerization reaction. By performing the aging step, the amount of residual monomer can be reduced. The temperature in the aging step is not particularly limited, but is preferably 20 to 110 ° C. More preferably, it is carried out at the above-mentioned polymerization temperature.
The aging time in the aging step is not particularly limited, but is preferably 10 minutes to 5 hours. More preferably, it is 15 minutes to 3 hours.

The above-mentioned method for producing a copolymer may include a step of adding hypophosphorous acid (salt) after the polymerization reaction. By performing such a step, the color resistance of the copolymer can be further improved.

In the above production method, the solid content concentration in the aqueous solution (that is, the polymerized solid content concentration of the monomer) at the time when the polymerization reaction is completed is preferably 15% by mass or more, and more preferably 20 to 70% by mass. .. If the solid content concentration at the end of the polymerization reaction is as high as 15% by mass or more, the polymerization reaction is carried out at a high concentration, so that the reaction rate and the reaction rate are increased, and the amount of residual monomers is suppressed more sufficiently. Can be done.

<Carboxyl group-containing copolymer composition>
The present invention is also a carboxyl group-containing copolymer composition containing the carboxyl group-containing copolymer of the present invention and a cross-linking agent.
The cross-linking agent is not particularly limited as long as it reacts with the carboxyl group and / or other reactive functional group of the copolymer to form a cross-linked structure.
The other reactive functional group of the copolymer is not particularly limited, and examples thereof include a sulfonic acid group and an ester or salt thereof; an amino group, a hydroxyl group and the like.
The cross-linking agent is not particularly limited, but for example, polyamines such as ethylene diamine, hexamethylene diamine, and phenylenediamine; alkanol amines such as monoethanolamine, diethanolamine, and triethanolamine; oxazoline group-containing polymers (Epocross manufactured by Nippon Catalyst Co., Ltd.). ), Divalent alcohols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyalkylene glycol (alcohols having two hydroxyl groups in the molecule); glycerin, polyglycerin, erythritol, xylitol, sorbitol, etc. Examples thereof include trihydric or higher alcohols (alcohols having three or more hydroxyl groups in the molecule); polyisocyanates such as tolylene diisocyanate and hexamethylene diisocyanate.

In the carboxyl group-containing copolymer composition, the proportion of the cross-linking agent is preferably 0 to 30% by mass with respect to 100% by mass of the above-mentioned copolymer. It is more preferably 0 to 20% by mass, and even more preferably 0 to 15% by mass.

<Use of carboxyl group-containing copolymer>
The carboxyl group-containing copolymer of the present invention is suitably used for applications such as surface coating agents, coating agents, and paints.
The base material for treating (coating) the carboxyl group-containing copolymer as a surface coating agent, coating agent, paint or the like is not particularly limited, and examples of the material include an inorganic base material and an organic base material. Be done. Examples of the inorganic base material include ceramic base materials made of clay, silica sand, limestone and the like, ceramic base materials such as roof tiles, glass and cement; and metal base materials. Examples of the organic base material include synthetic resins and plant-based materials. Examples of the synthetic resin include thermoplastic resins such as acrylic resin, (saturated) polyester resin, polyethylene resin, polypropylene resin and polystyrene resin; and thermosetting resins such as unsaturated polyester resin, epoxy resin, phenol resin and melamine resin.
The shape of the base material is also not particularly limited, and examples thereof include a plate shape, a film shape, a sheet shape, and a fibrous shape.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "part" means "part by weight" and "%" means "mass%".

<Measurement conditions for polymerization average molecular weight>
Equipment: HLC-8320GPC manufactured by Tosoh Corporation
Detector: RI
Column: Showa Denko SHODEX Asahipak GF-310-HQ,
GF-710-HQ, GF-1G 7B
Column temperature: 40 ° C
Flow velocity: 0.5 mL / min.
Calibration curve: Polyacrylic acid standard eluent manufactured by Sowa Kagaku Co., Ltd .: 0.1N Sodium acetate / acetonitrile = 3/1 (mass ratio)

<Method for measuring solid content of aqueous polymer solution>
The binder was left to dry in an oven heated to 120 ° C. for 120 minutes. The solid content (%) was calculated from the weight change before and after drying.

<Heat resistance test>
(I) Ion-exchanged water is added to the polymer composition to adjust the solid content to 15%.
(Ii) 2.0 g of the polymer composition obtained in (i) is applied to a glass fiber filter (GA-410 manufactured by ADVANTEC).
(Iii) The glass fiber filter obtained in (ii) above is dried in an oven at 190 ° C. for 20 minutes.
(Iv) The W value is measured with a spectroscopic color difference meter SE-2000 (reflection mode) manufactured by Nippon Denshoku Industries Co., Ltd.

<Water resistance test>
(I) Ion-exchanged water is added to the polymer composition to adjust the solid content to 40%.
(Ii) 3% of Elastron BN-69 (polyisocyanate-based cross-linking agent) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. is added as a cross-linking agent to the polymer composition obtained in (i) above, and the mixture is sufficiently mixed.
(Iii) 3 g of the liquid obtained in (ii) above was left in an oven heated to 80 ° C. for 60 minutes, and further left in an oven heated to 130 ° C. for 10 minutes to obtain a solid substance.
(Iv) The solid obtained in (iii) above was immersed in ion-exchanged water for 90 minutes.
(V) Filtration was performed, and the residue was left in an oven heated to 130 ° C. for 90 minutes to dry.
(Vi) From the weight ratio of the solids obtained in (v) and (iii) above, the residual ratio of the solids before and after immersion in ion-exchanged water was calculated. Water resistance was evaluated by the solid content residual ratio.

<Example 1>
384.7 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 281.8 g (that is, 3.13 mol) of an 80 mass% acrylic acid aqueous solution (hereinafter referred to as “80% AA”) was added to a polymerization reaction system at 87 ° C. for 120 minutes, and 10 mol of ethylene oxide of 80 mass% isoprenol. 229.0 g (ie, 0.54 mol) of an aqueous adduct solution (hereinafter referred to as "80% IPN10") for 110 minutes, 69.6 g of a 15 mass% aqueous sodium persulfate solution (hereinafter referred to as "15% NaPS") for 130 minutes. 6.3 g of a 45 mass% sodium hypophosphite aqueous solution (hereinafter referred to as "45% SHP") was added for 18 minutes, followed by 12.9 g for 92 minutes at two different supply rates. Dropped from the nozzle. The dropping of each component was continuously carried out at a constant dropping rate except for 45% SHP. After the completion of dropping 80% AA, the reaction solution was kept at 87 ° C. (aged) for another 40 minutes to complete the polymerization. After completion of the polymerization, after cooling to 40 ° C., 15.7 g (that is, 0.19 mol) of a 48 mass% sodium hydroxide aqueous solution (hereinafter referred to as “48% NaOH”) was added under stirring to obtain a polymer aqueous solution (A1). rice field. The solid content measurement result of the polymer aqueous solution (A1) was 43.1%, the weight average molecular weight (Mw) was 42,000, the heat resistance test result showed a W value of 78, and the solid content residual ratio before and after the water resistance test evaluation was 74. %Met.

<Example 2>
376.0 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 80% AA: 212.9 g (ie 2.37 mol) was added to the polymerization reaction system at 87 ° C. for 120 minutes, 80% IPN10: 319.4 g (ie 0.49 mol) was added to the polymerization reaction system for 110 minutes, and 15% NaPS: 57.0 g was added dropwise from the tip nozzle for 130 minutes, 45% SHP: 7.6 g for 18 minutes, and then 15.2 g for 92 minutes at two different supply rates. The dropping of each component was continuously carried out at a constant dropping rate except for 45% SHP. After the completion of dropping 80% AA, the reaction solution was kept at 87 ° C. (aged) for another 40 minutes to complete the polymerization. After completion of the polymerization, the mixture was cooled to 40 ° C., and 48% NaOH: 11.8 g (that is, 0.14 mol) was added under stirring to obtain an aqueous polymer solution (A2). The solid content measurement result of the polymer aqueous solution (A2) was 44.6%, the weight average molecular weight (Mw) was 24,000, the heat resistance test result showed a W value of 77, and the solid content residual ratio before and after the water resistance test evaluation was 65. %Met.

<Example 3>
362.6 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 80% AA: 212.3 g (ie 2.36 mol) was added to the polymerization reaction system at 87 ° C. for 120 minutes, 80% IPN10: 318.4 g (ie 0.48 mol) was added to the polymerization reaction system for 110 minutes, and 15% NaPS: 56.9 g for 130 minutes, 11.4 g of a 15 mass% sodium hypophosphite aqueous solution (hereinafter referred to as "15% SHP") for 18 minutes, and then 22.7 g for 92 minutes at a two-step supply rate. Drops were made from the tip nozzle through separate supply paths. The dropping of each component was continuously carried out at a constant dropping rate except for 15% SHP. After the completion of dropping 80% AA, the reaction solution was kept at 87 ° C. (aged) for another 40 minutes to complete the polymerization. After completion of the polymerization, the mixture was cooled to 40 ° C., and 48% NaOH: 15.7 g (that is, 0.19 mol) was added under stirring to obtain an aqueous polymer solution (A3). The solid content measurement result of the polymer aqueous solution (A3) was 44.3%, the weight average molecular weight (Mw) was 53,000, the heat resistance test result showed a W value of 75, and the solid content residual ratio before and after the water resistance test evaluation was 75. %Met.

<Example 4>
292.8 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 80% AA: 199.5 g (that is, 2.22 mol) was placed in a polymerization reaction system at 87 ° C. for 120 minutes with an aqueous solution of a 50 mol adduct of ethylene oxide of 60 mass% isoprenol (hereinafter referred to as “60% IPN50”). ) 398.9 g (ie 0.10 mol) for 110 minutes, 15% NaPS: 47.1 g for 130 minutes, 15% SHP: 15.6 g for 18 minutes, followed by 31.3 g for 92 minutes, in two stages. Drops were made from the tip nozzle at different speeds through separate supply paths. The dropping of each component was continuously carried out at a constant dropping rate except for 15% SHP. After the completion of dropping 80% AA, the reaction solution was kept at 87 ° C. (aged) for another 40 minutes to complete the polymerization. After completion of the polymerization, the mixture was cooled to 40 ° C., and 48% NaOH: 14.8 g (that is, 0.18 mol) was added under stirring to obtain an aqueous polymer solution (A4). The solid content measurement result of the polymer aqueous solution (A4) was 41.8%, the weight average molecular weight (Mw) was 50,000, the heat resistance test result showed a W value of 75, and the solid content residual ratio before and after the water resistance test evaluation was 71. %Met.

<Example 5>
382.4 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 80% AA: 280.1 g (ie 3.11 mol) was added to the polymerization reaction system at 87 ° C. for 120 minutes, 80% IPN10: 227.6 g (ie 0.35 mol) was added to the polymerization reaction system for 110 minutes, and 15% NaPS: 69.2 g was added dropwise from the tip nozzle for 130 minutes, 45% SHP: 9.1 g for 18 minutes, and then 18.6 g for 92 minutes at two different supply rates. The dropping of each component was continuously carried out at a constant dropping rate except for 45% SHP. After the completion of dropping 80% AA, the reaction solution was kept at 87 ° C. (aged) for another 40 minutes to complete the polymerization. After completion of the polymerization, the mixture was cooled to 40 ° C., and 13.0 g (that is, 0.16 mol) of 48% NaOH was added under stirring to obtain an aqueous polymer solution (A5). The solid content measurement result of the polymer aqueous solution (A5) was 43.2%, the weight average molecular weight (Mw) was 18,000, the heat resistance test result showed a W value of 79, and the solid content residual ratio before and after the water resistance test evaluation was 58. %Met.

<Example 6>
386.2 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 80% AA: 357.9 g (ie 3.98 mol) for 120 minutes and 80% IPN 10: 153.4 g (ie 0.23 mol) for 110 minutes in a polymerization reaction system at 87 ° C., 15% NaPS: 84.2 g was added dropwise from the tip nozzle for 130 minutes, 45% SHP: 6.0 g for 18 minutes, and then 12.3 g for 92 minutes at two different supply rates. The dropping of each component was continuously carried out at a constant dropping rate except for 45% SHP. After the completion of dropping 80% AA, the reaction solution was held (aged) at 87 ° C. for another 40 minutes to complete the polymerization, and an aqueous polymer solution (A6) was obtained. The solid content measurement result of the polymer aqueous solution (A6) was 43.2%, the weight average molecular weight (Mw) was 40,000, the heat resistance test result showed a W value of 77, and the solid content residual ratio before and after the water resistance test evaluation was 67. %Met.

<Example 7>
318.1 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 80% AA: 367.2 g (ie 4.08 mol) for 120 minutes, 80% IPN 10: 64.8 g (ie 0.10 mol) for 110 minutes, 15% NaPS: in a polymerization reaction system at 87 ° C. 83.6 g was added dropwise from the tip nozzle for 130 minutes, 45% SHP: 5.4 g for 18 minutes, and then 10.9 g for 92 minutes at two different supply rates. The dropping of each component was continuously carried out at a constant dropping rate except for 45% SHP. After the completion of dropping 80% AA, the reaction solution was held (aged) at 87 ° C. for another 40 minutes to complete the polymerization, and an aqueous polymer solution (A7) was obtained. The solid content measurement result of the polymer aqueous solution (A7) was 43.2%, the weight average molecular weight (Mw) was 43,000, the heat resistance test result showed a W value of 82, and the solid content residual ratio before and after the water resistance test evaluation was 65. %Met.

<Example 8>
272.3 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 95 ° C. under stirring. Then, under stirring, 80% AA: 270.8 g (ie, 3.01 mol) was added to the polymerization reaction system at 95 ° C. for 120 minutes, 60% IPN50: 295.5 g (ie, 0.08 mol) was added to the polymerization reaction system for 110 minutes, and 15% NaPS: 51.4 g was added dropwise from the tip nozzle for 130 minutes, 15% SHP: 8.2 g for 18 minutes, and then 26.4 g for 102 minutes at two different supply rates. The dropping of each component was continuously carried out at a constant dropping rate except for 15% SHP. After the completion of the dropping of 80% AA, the reaction solution was held (aged) at 95 ° C. for another 40 minutes to complete the polymerization. After completion of the polymerization, the mixture was cooled to 40 ° C., and 48% NaOH: 75.2 g (that is, 0.90 mol) was added under stirring to obtain an aqueous polymer solution (A8). The solid content measurement result of the polymer aqueous solution (A8) was 43.3%, the weight average molecular weight (Mw) was 147,000, the heat resistance test result showed a W value of 75, and the solid content residual ratio before and after the water resistance test evaluation was 54. %Met.

<Example 9>
372.8 g of ion-exchanged water was charged (initially charged) into a 2.5 L SUS reaction vessel equipped with a reflux condenser and a stirrer, and the temperature was raised to 87 ° C. under stirring. Then, under stirring, 80% AA: 211.1 g (ie 2.35 mol) was added to the polymerization reaction system at 87 ° C. for 120 minutes, 80% IPN10: 316.7 g (ie 0.48 mol) was added to the polymerization reaction system for 110 minutes, and 15% NaPS: 56.5 g was added dropwise from the tip nozzle for 130 minutes, 15% SHP: 9.0 g for 18 minutes, and then 18.1 g for 92 minutes at two different supply rates. The dropping of each component was continuously carried out at a constant dropping rate except for 15% SHP. After the completion of dropping 80% AA, the reaction solution was kept at 87 ° C. (aged) for another 40 minutes to complete the polymerization. After completion of the polymerization, the mixture was cooled to 40 ° C., and 48% NaOH: 15.6 g (that is, 0.19 mol) was added under stirring to obtain an aqueous polymer solution (A9). The solid content measurement result of the polymer aqueous solution (A9) was 44.3%, the weight average molecular weight (Mw) was 80,000, the heat resistance test result showed a W value of 75, and the solid content residual ratio before and after the water resistance test evaluation was 78. %Met.

<Comparative example 1>
300.0 g of ion-exchanged water was charged (initially charged) into a 2.5-liter SUS separable flask equipped with a reflux condenser, a stirrer (paddle blade), and a thermometer, and the temperature was raised to the boiling point under stirring. Then, under stirring, 80% AA: 425.3 g (that is, 4.73 mol) was added to an ethylene oxide 5 mol adduct of allyl alcohol (hereinafter, “allyl alcohol 5EO” (PEA5)) in a polymerization reaction system in a boiling point reflux state for 180 minutes. 146.2 g (ie 0.53 mol) for 150 minutes, 15% NaPS: 26.3 g for 195 minutes, 45% SHP: 12.5 g for 18 minutes, followed by 49.0 g for 162 minutes in two steps. Dropped from the tip nozzle through different supply paths at the same supply rate. The dropping of each component was continuously carried out at a constant dropping rate except for 45% SHP. After the completion of the dropping of 80% AA, the reaction solution was kept in a boiling point reflux state (aged) for another 30 minutes to complete the polymerization, and a polymer aqueous solution (B1) was obtained. The solid content measurement result of the aqueous polymer solution (B1) was 54.5%, the weight average molecular weight (Mw) was 5,900, and the solid content residual ratio before and after the water resistance test evaluation was 49%.

The results of the water resistance tests of the copolymers obtained in Examples 1 to 9 and Comparative Example 1 are shown in Table 1 together with the monomer composition ratio and the weight average molecular weight.

Claims (8)

The structural unit (a) derived from the unsaturated carboxylic acid monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles of groups added and is a number from 2 to 80. X represents a number from 0 to 2. y represents a 0 or 1 polyalkylene glycol-based monomer (representing 0 or 1). B) Contains a carboxyl group-containing copolymer having a structural unit (b) derived from it and a cross-linking agent.
The copolymer has a phosphorus atom-containing group in the molecule and has a weight average molecular weight of 10,000 or more and 150,000 or less .
The ratio of the structural unit (a) is 20 to 85% by mass with respect to 100% by mass of all structural units, and the ratio of the structural unit (b) is 15 to 80% by mass with respect to 100% by mass of all structural units. A carboxyl group-containing copolymer composition comprising. The carboxyl group-containing copolymer composition according to claim 1 , wherein x in the formula (1) is 2 and y is 0. The carboxyl group-containing copolymer composition according to claim 1 or 2 ^{, wherein R 3} in the formula (1) is a methyl group. The carboxyl group-containing copolymer composition according to any one of claims 1 to 3 , wherein the phosphorus atom-containing group has a structure derived from hypophosphorous acid (salt). The structural unit (a) derived from the unsaturated carboxylic acid monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles of groups added and is a number from 2 to 80. X represents a number from 0 to 2. y represents a 0 or 1 polyalkylene glycol-based monomer (representing 0 or 1). A surface coating agent containing a carboxyl group-containing copolymer having a structural unit (b) derived from B).
The copolymer has a phosphorus atom-containing group in the molecule and has a weight average molecular weight of 10,000 or more and 150,000 or less .
The ratio of the structural unit (a) is 20 to 85% by mass with respect to 100% by mass of all structural units, and the ratio of the structural unit (b) is 15 to 80% by mass with respect to 100% by mass of all structural units. A surface coating agent characterized by. The structural unit (a) derived from the unsaturated carboxylic acid monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles of groups added and is a number from 2 to 80. X represents a number from 0 to 2. y represents a 0 or 1 polyalkylene glycol-based monomer (representing 0 or 1). A coating agent containing a carboxyl group-containing copolymer having a structural unit (b) derived from B).
The copolymer has a phosphorus atom-containing group in the molecule and has a weight average molecular weight of 10,000 or more and 150,000 or less .
The ratio of the structural unit (a) is 20 to 85% by mass with respect to 100% by mass of all structural units, and the ratio of the structural unit (b) is 15 to 80% by mass with respect to 100% by mass of all structural units. A coating agent characterized by. The structural unit (a) derived from the unsaturated carboxylic acid monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles of groups added and is a number from 2 to 80. X represents a number from 0 to 2. y represents a 0 or 1 polyalkylene glycol-based monomer (representing 0 or 1). A coating material containing a carboxyl group-containing copolymer having a structural unit (b) derived from B).
The copolymer has a phosphorus atom-containing group in the molecule and has a weight average molecular weight of 10,000 or more and 150,000 or less .
The ratio of the structural unit (a) is 20 to 85% by mass with respect to 100% by mass of all structural units, and the ratio of the structural unit (b) is 15 to 80% by mass with respect to 100% by mass of all structural units. A paint that features. A method for producing a carboxyl group-containing copolymer composition containing a carboxyl group-containing copolymer and a cross-linking agent.
The production method is an unsaturated carboxylic acid-based monomer (A) and the following formula (1);

(In the formula, R ¹ , R ² and R ³ represent the same or different hydrogen atom or methyl group. (AO) represents the same or different oxyalkylene group. N represents an oxyalkylene group. It represents the average number of moles added of a group and is a number from 2 to 80. X represents a number from 0 to 2. y represents 0 or 1) to form a structural unit (b). A step of polymerizing a monomer component containing a polyalkylene glycol-based monomer (B) using a chain transfer agent containing a phosphorus atom-containing compound, and a carboxyl group-containing copolymer obtained in the polymerization step. Including the step of adding a cross-linking agent
The ratio of the unsaturated carboxylic acid-based monomer (A) in the monomer component is 20 to 85% by mass with respect to 100% by mass of all the monomers, and the ratio of the polyalkylene glycol-based monomer (B). Is 15 to 80% by mass based on 100% by mass of all the monomers.
A method for producing a carboxyl group-containing copolymer composition, wherein the carboxyl group-containing copolymer has a weight average molecular weight of 10,000 or more and 150,000 or less.