JP2022018857A - Method for producing n-vinylamide-based polymer and n-vinylamide-based polymer - Google Patents

Abstract

To provide a method for producing an N-vinylamide-based polymer, capable of efficiently producing an N-vinylamide-based polymer excellent in heat resistance with small amounts of residual monomers and by-products.SOLUTION: The method for producing an N-vinylamide-based polymer includes a step of polymerizing monomer components including a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactam-based monomer (b) in a polymerization solvent containing an alcoholic solvent. The total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) is 85 mass% or more based on 100 mass% of the total amount of the monomer components.SELECTED DRAWING: None

Description

The present invention relates to a method for producing an N-vinylamide polymer. More specifically, a method for producing an N-vinylamide polymer capable of efficiently obtaining an N-vinylamide polymer having a small amount of residual monomers and by-products and excellent heat resistance, and an N-vinylamide polymer. Regarding.

The N-vinylamide polymer is a polymer having a structural unit derived from an N-vinylamide monomer, and is a safe functional polymer such as cosmetics, medical and agricultural chemical intermediates, food additives, photosensitive electronic materials, and adhesives. It is used in a wide range of industrial applications such as various applications such as additives and various special industrial applications (for example, manufacturing of hollow fiber membranes).

So far, various N-vinylamide-based copolymers and various methods for producing the same have been studied.
For example, Patent Document 1 describes A) N-vinylpyrrolidone, N-vinylcaprolactam and N-vinylimidazole in an alcohol solution as a polymer film-forming polymer that is well-soluble in alcohol and suitable for hair cosmetics. At least one monomer from the group 15-84.99% by weight, B) other radical copolymerizable monoolefinically unsaturated monomers 15-84.99% by weight, C) at least two non-conjugated olefinic doubles A copolymer having a K value of 30 to 50, which is obtained by radical solution polymerization of 0.01 to 2% by weight of a radical copolymerizable monomer having a bond, is described.

Further, for example, in Patent Document 2, since the N-vinylpyrrolidone-based polymer solution obtained by various polymerization methods has high viscosity, the N-vinylpyrrolidone-based polymer powder sufficiently dried from such a polymerization solution is powder. A manufacturing method for obtaining a body is described.

Further, for example, in Patent Document 3, as a polymer having more excellent stability, dispersibility and calcium ion trapping ability, a (meth) acrylic acid monomer is added to a basic polymer having an N-vinyl cyclic lactam unit as a radical initiator. Described are N-vinyl cyclic lactam-based graft polymers obtained by polymerization in the presence of.

Japanese Unexamined Patent Publication No. 8-231649 Japanese Unexamined Patent Publication No. 2009-244973 Japanese Unexamined Patent Publication No. 2010-47693

However, when a monomer component containing a cyclic N-vinylamide-based monomer and an N-vinylcaprolactam-based monomer is polymerized, the conventional polymerization method has low reactivity and the amount of residual monomer and by-products is large. There is a problem that a copolymer having a uniform composition cannot be efficiently obtained. Further, it cannot be said that the obtained N-vinylamide copolymer has sufficient heat resistance, and there is still room for improvement.

In view of the above situation, the present invention provides a method for producing an N-vinylamide polymer capable of efficiently producing an N-vinylamide polymer having a small amount of residual monomers and by-products and excellent heat resistance. The purpose is to provide.

The present inventor has studied various methods for producing an N-vinylamide-based polymer in order to solve the above problems, and found that a specific range of cyclic N-vinylamide-based monomers and N in the presence of a specific solvent. -It was found that by polymerizing a monomer component containing a vinylcaprolactum-based monomer, an N-vinylamide-based polymer having a small amount of residual monomers and by-products and excellent heat resistance can be efficiently produced. .. Further, by polymerizing a monomer component containing a specific range amount of the cyclic N-vinylamide-based monomer and the N-vinylcaprolactam-based monomer in the presence of a specific compound, the amount of residual monomer and by-products can be increased. It has been found that an N-vinylamide-based polymer having a small amount and excellent heat resistance can be efficiently produced, and the present invention has been completed.

That is, the present invention polymerizes a monomer component containing a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactum-based monomer (b) in a polymerization solvent containing an alcohol-based solvent. Including the step, the total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactum-based monomer (b) is 85% by mass or more with respect to 100% by mass of the total amount of the monomer components. It is a method for producing an N-vinylamide-based polymer, which is characterized by being present.

In the method for producing the N-vinylamide polymer, the alcohol solvent preferably has a boiling point of 100 ° C. or lower.

In the method for producing the N-vinylamide polymer, the polymerization solvent preferably further contains water.

In the method for producing an N-vinylamide polymer, the polymer solvent preferably has a mass ratio of an alcohol solvent to water of 95/5 to 5/95.

The present invention also polymerizes a monomer component containing a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactum-based monomer (b) in the presence of a phosphorus compound having a chain transfer ability. The total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactum-based monomer (b) is 85% by mass or more with respect to 100% by mass of the total amount of the monomer components. A method for producing an N-vinylamide-based polymer, which is characterized by the above.

The phosphorus compound having a chain transfer ability is preferably hypophosphoric acid (salt) and / or phosphorous acid (salt).

The present invention also has a structural unit (A) derived from a cyclic N-vinylamide-based monomer and a structural unit (B) derived from an N-vinylcaprolactum-based monomer, and the above-mentioned cyclic N-vinylamide-based single amount. The total content ratio of the structural unit (A) derived from the body and the structural unit (B) derived from the N-vinylcaprolactam-based monomer is 85% by mass or more with respect to 100% by mass of the total structural unit, and the following general formula is used. It is an N-vinylamide-based polymer characterized by having a main chain terminal structure represented by (2).

（式中、Ｒ^４は、水素原子、又は、水酸基を有してもよい炭素数１～５のアルキル基を表す。）

(In the formula, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms which may have a hydroxyl group.)

The present invention also has a structural unit (A) derived from a cyclic N-vinylamide-based monomer and a structural unit (B) derived from an N-vinylcaprolactum-based monomer, and the above-mentioned cyclic N-vinylamide-based single amount. The total content ratio of the structural unit (A) derived from the body and the structural unit (B) derived from the N-vinylcaprolactam-based monomer is 85% by mass or more with respect to 100% by mass of the total structural unit, and the following general formula is used. It is also an N-vinylamide-based polymer characterized by having a main chain terminal structure represented by (3).

（式中、Ｍ^１及びＭ^２は、同一又は異なって、水素原子、又は、金属原子を表す。）

(In the formula, M ¹ and M ² are the same or different and represent a hydrogen atom or a metal atom.)

According to the present invention, it is possible to efficiently produce an N-vinylamide-based polymer having a small amount of residual monomers and by-products and having excellent heat resistance.

The present invention will be described in detail below.
It should be noted that a combination of two or more of the individual preferred embodiments of the present invention described below is also a preferred embodiment of the present invention.
In the present specification, "(meth) acrylic acid" is a general term for "acrylic acid" and "methacrylic acid", and "(meth) acrylate" is a general term for "acrylate" and "methacrylate".

1. 1. Method for Producing N-Vinylamide Polymer <First Production Method of the Present Invention>
In the first aspect of the present invention, a monomer component containing a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactum-based monomer (b) is polymerized in a polymerization solvent containing an alcohol-based solvent. The total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactum-based monomer (b) is 85% by mass or more with respect to 100% by mass of the total amount of the monomer components. This is a method for producing an N-vinylamide-based polymer, which is characterized by the above. According to the first method for producing an N-vinylamide polymer of the present invention, an N-vinylamide polymer having a small amount of residual monomers and by-products and excellent heat resistance can be efficiently obtained.

The reason why the N-vinylamide polymer having excellent heat resistance can be efficiently obtained by the first production method of the present invention is that the alcohol solvent acts as a chain transfer agent and is incorporated into the polymer terminal. It is presumed that this is because the depolymerization of the polymer that occurs at high temperatures is suppressed.

The first production method of the present invention is a monomer containing a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactam-based monomer (b) in a polymerization solvent containing an alcohol solvent. Includes a step of polymerizing the components.

As the alcohol solvent, for example, a saturated alcohol, that is, a compound having no unsaturated double bond and containing at least one hydroxyl group is preferably mentioned.
Specific examples of the alcohol solvent include monoalcohols such as methanol, ethanol, n-propanol, isopropanol (2-propanol), n-butanol, s-butanol, t-butanol, isobutanol, and cyclohexanol; Examples thereof include polyhydric alcohols such as ethylene glycol, propylene glycol and diethylene glycol.

The carbon number of the alcohol solvent is preferably 1 to 6, more preferably 2 to 5, and even more preferably 2 to 4 in terms of increasing the chain transfer ability of the polymerization.

The alcohol solvent preferably has a boiling point of 100 ° C. or lower. When an alcohol solvent having a boiling point of 100 ° C. or lower is used, the drying efficiency at the time of powdering can be improved. The alcohol-based solvent preferably has a boiling point of 95 ° C. or lower, more preferably 90 ° C. or lower.

Among them, as the alcohol solvent, methanol, ethanol, n-propanol and isopropanol are preferable, and ethanol and isopropanol are more preferable, because the heat resistance can be further improved.

The alcohol solvent may be used alone or in combination of two or more.

The amount of the alcohol solvent used is preferably 5 to 95% by mass based on 100% by mass of the polymerization solvent. The above-mentioned polymerization solvent 100% by mass means that the total amount of the solvent used in the polymerization step is 100% by mass. When the amount of the alcohol solvent used is in the above range, a polymer having further excellent heat resistance can be produced. The amount of the alcohol solvent used is more preferably 8% by mass or more, further preferably 10% by mass or more, still more preferably 92% by mass or less, and 90% by mass, based on 100% by mass of the polymerization solvent. It is more preferably mass% or less.

In the first production method of the present invention, another solvent may be further contained as the polymerization solvent.
Examples of the other solvent include water; cyclic ethers such as tetrahydrofuran and dioxane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and propylene. Glycol monoethyl ethers such as glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, 3-methoxybutanol; ketone solvents such as acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone; methyl acetate, ethyl acetate, propyl acetate, etc. Alkyl ester solvents such as isopropyl acetate, butyl acetate, methyl propionate; aromatic hydrocarbon solvents such as benzene, toluene, ethylbenzene, xylene; aliphatic hydrocarbons such as hexane, cyclohexane, heptane, octane; etc. Be done. Only one of these may be used, or two or more thereof may be used in combination.

Among them, as the above-mentioned other solvent, water is preferable in that the amount of residual monomers and by-products can be further reduced. By further including water in the solvent in addition to the alcohol-based solvent, the reactivity between the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) is increased. The reaction rate of the monomers is further increased, the amount of residual monomers is reduced, and the above-mentioned polymer can be obtained more efficiently.
The water is not particularly limited, and examples thereof include distilled water, ion-exchanged water, and pure water.

The mass ratio of the alcohol solvent to the other solvent in the polymerization solvent is preferably 95/5 to 5/95, preferably 92/8 to 8 in that a polymer having better heat resistance can be obtained. It is more preferably / 92, further preferably 90/10 to 10/90, and even more preferably 90/10 to 50/50.

The amount of the polymerization solvent used is not particularly limited and may be appropriately set by a known method. For example, it is 45 to 900 parts by mass with respect to 100 parts by mass of the total amount of the monomer components used in the polymerization step. It is preferably 65 to 600 parts by mass, more preferably 80 to 400 parts by mass.

In the above polymerization step, at least a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactam-based monomer (b) are used as the monomer components.
The cyclic N-vinylamide-based monomer (a) used in the first invention is a cyclic N-vinylamide-based monomer, and is preferably a compound represented by the following general formula (1).

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² and R ³ are the same or different hydrocarbon groups having 1 to 10 carbon atoms which may have a hydrogen atom or a substituent. N represents an integer of 1 to 4. A plurality of R ² and R ³ may be the same or different from each other.)

In the above general formula (1), R ² and R ³ represent the same or different hydrocarbon groups having 1 to 10 carbon atoms which may have a hydrogen atom or a substituent.
Examples of the above-mentioned hydrocarbon group include preferably an aliphatic hydrocarbon group, more preferably an aliphatic saturated hydrocarbon group, and further preferably an alkyl group.
The hydrocarbon group having 1 to 10 carbon atoms is preferably a hydrocarbon group having 1 to 4 carbon atoms, more preferably an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and having 1 to 4 carbon atoms. The alkyl group is more preferable, and the methyl group and the ethyl group are particularly preferable.
The hydrocarbon group may have a substituent, and examples of the substituent include an alkyl group having 1 to 6 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 6 carbon atoms, and the like, preferably a methyl group. Examples include hydroxyl groups.

Specific examples of the compound represented by the above general formula (1) include, for example, N-vinyl-2-pyrrolidone, 3-methyl-N-vinylpyrrolidone, 4-methyl-N-vinylpyrrolidone, and 5-methyl-N. -Vinylpyrrolidone, N-vinylpiperidone and the like can be mentioned. Of these, N-vinyl-2-pyrrolidone is preferable because of its high reactivity.

The cyclic N-vinylamide-based monomer (a) may be used alone or in combination of two or more.
The content ratio of the cyclic N-vinylamide-based monomer (a) is preferably 5 to 95% by mass based on 100% by mass of the total amount of the monomer components, and the obtained polymer is highly soluble in water. In that respect, it is more preferably 10% by mass or more, further preferably 20% by mass or more, further preferably 90% by mass or less, still more preferably 85% by mass or less.

The N-vinylcaprolactam-based monomer (b) used in the first invention includes, for example, N-vinyl-ε-caprolactam and at least one hydrogen atom of N-vinyl-ε-caprolactam as a substituent. Examples include compounds replaced with. Examples of the substituent include the same group as the substituent described in the above-mentioned monomer (a).

The content ratio of the N-vinylcaprolactum-based monomer (b) is preferably 5 to 95% by mass based on 100% by mass of the total amount of the monomer components, and the heat resistance of the obtained polymer is higher. It is more preferably 10% by mass or more, further preferably 15% by mass or more, further preferably 90% by mass or less, and further preferably 80% by mass or less.

In the first production method of the present invention, the total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) is 100% by mass based on the total amount of the monomer components. It is 85% by mass or more. When the total amount of the monomer (a) and the monomer (b) occupies the above range in the total amount of the monomer components, an N-vinylamide polymer having excellent heat resistance can be obtained. The total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactum-based monomer (b) is the total mass of the monomer components in that a polymer having even better heat resistance can be obtained. It is preferably 88% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably 100% by mass with respect to 100% by mass.

The monomer component may contain another monomer (c) in addition to the above-mentioned monomer (a) and monomer (b).
The other monomer (c) may be, for example, a monomer that can be polymerized with the above-mentioned monomers (a) and (b) and that can obtain the effects of the present invention. However, the following monomers can be mentioned, for example, without particular limitation. Only one kind of these monomers may be used, or two or more kinds thereof may be used.

Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate. , (Meta) dicyclopentanyl acrylate, (meth) isobornyl acrylate, (meth) adamantyl acrylate, hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate and other (meth) acrylic acid esters; N -Methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-stearylmaleimide, N-methylphenylmaleimide, N-hydroxyethylmaleimide, N-benzylmaleimide, N-phenylmaleimide , N-substituted maleimides such as N-cyclohexyl maleimide; (meth) acrylamide derivatives such as (meth) acrylamide, N-monomethyl (meth) acrylamide, N-monoethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide. Kind; Basic unsaturated monomers such as dimethylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, vinylpyridine, vinyl imidazole and salts thereof or quaternary products; (meth) acrylic acid, itaconic acid. , Maleic acid, fumaric acid and other carboxyl group-containing unsaturated monomers and salts thereof; unsaturated anhydrides such as maleic anhydride and itaconic acid anhydride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethylene carbonate And its derivatives; (meth) acrylic acid-2-sulfonic acid ethyl and its derivatives; vinyl sulfonic acid and its derivatives; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether; olefins such as ethylene, propylene, octene, butadiene etc.

The content ratio of the other monomer (c) is preferably 0 to 15% by mass, more preferably 0 to 10% by mass, and 0 to 0 to 100% by mass with respect to 100% by mass of the total amount of the monomer components. It is more preferably 5% by mass.

The polymerization reaction in the polymerization step is not particularly limited except that a polymerization solvent containing the alcohol solvent is used, and can be carried out by a known method such as radical polymerization using a polymerization initiator or the like.
In the above polymerization step, when the monomer components are mixed and reacted, one monomer may be collectively added to the other monomer and mixed, or sequentially added and mixed to react. You may let me.

In the above polymerization step, the polymerization temperature is not particularly limited, but is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and even more preferably 50 ° C. or higher. Further, the temperature is preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and further preferably 85 ° C. or lower, in that polymerization can be easily performed without the need for a pressure-resistant container such as an autoclave. preferable.

The polymerization time is not particularly limited, but is preferably 1 hour or longer, more preferably 2 hours or longer, and even more preferably 3 hours or longer. Further, in terms of good productivity, it is preferably 20 hours or less, more preferably 10 hours or less, and further preferably 8 hours or less.

The polymerization step may be carried out in the atmosphere or in an atmosphere of an inert gas such as nitrogen. Further, the polymerization reaction may be carried out under any of the conditions of normal pressure, pressurization and reduced pressure.
Water may be present in the polymerization step.

The polymerization step is also preferably carried out in the presence of one or more polymerization initiators. As the polymerization initiator, a known radical polymerization initiator can be used.

Examples of the polymerization initiator include persulfates such as ammonium persulfate, sodium persulfate, potassium persulfate; hydrogen peroxide; di-t-butyl peroxide, di-t-amyl peroxide, di-t-hexyl. Dialkyl peroxides such as peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 1,3-bis (t-butylperoxyisopropyl) benzene, t-butylperoxyisopropyl Monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-butylperoxylaurate, t-butylperoxybenzoate, t-amylperoxyisononanoate, t-amylperoxy-2-ethylhexanoate Peroxy esters such as ate, t-butylperoxypivalate, 1,1-di (t-butylperoxy) cyclohexane, and peroxy such as 4,4-bis [(t-butyl) peroxy] butylpentanoate. Hydroperoxides such as ketals, t-butylhydroperoxide, cumenhydroperoxide, diisopropylbenzenehydroperoxide, ketone peroxides such as methylethylketone peroxide, dilauryl peroxide, dibenzoyl peroxide and the like. Organic peroxides such as oxides, peroxydicarbonates such as di (2-ethylhexyl) peroxydicarbonate; dimethyl 2,2'-azobis (2-methylpropionate), 2,2'-azobis (Isobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 2,2'-azobis [N- (2) -Carboxyethyl) -2-methylpropionamidine] hydrate, 2,2'-azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2- (2-imidazolin-) 2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-imidazolin-2-yl) propane] disulfate hydrate, 2,2'-azobis (1-imino-1-pyrrolidino) -2-Methylpropane) dihydrochloride, 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] n hydrate, 2,2'-azobis [2-methyl-N- (2-Hydroxyethyl) propionamide] and the like; Among them, organic peroxides and / or azo compounds are preferable because the polymerization reaction proceeds efficiently and residual monomers and by-products can be reduced, and azo compounds are more preferable because the molecular weight can be adjusted. ..

The amount of the polymerization initiator used is not particularly limited, but is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the total amount of the monomer components in that the molecular weight can be adjusted with a low impurity amount. 0.1 to 5 parts by mass is more preferable, and 0.2 to 3 parts by mass is further preferable.

In the above-mentioned polymerization step, in addition to the above-mentioned components, other components usually used in the polymerization reaction such as a chain transfer agent, a catalyst, a pH adjuster and the like may be used. These types and amounts can be appropriately selected from known techniques.

The first manufacturing method of the present invention may have other steps in addition to the above-mentioned steps. Examples thereof include an aging step, a neutralization step, a deactivation step of a polymerization initiator and the like, a dilution step, a concentration step, a purification step and the like. These steps can be performed by a known method. Further, the order of these steps can also be appropriately selected by a known method.

<Second manufacturing method of the present invention>
The second aspect of the present invention is a monomer component containing a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactum-based monomer (b) in the presence of a phosphorus compound having a chain transfer ability. The total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactum-based monomer (b) is 85% by mass with respect to 100% by mass of the total amount of the monomer components. % Or more, which is a method for producing an N-vinylamide-based polymer. According to the second method for producing an N-vinylamide polymer of the present invention, an N-vinylamide polymer having excellent heat resistance can be efficiently obtained.

According to the second production method of the present invention, an N-vinylamide-based polymer having excellent heat resistance can be efficiently obtained by introducing a structure derived from a phosphorus compound used as a chain transfer agent into the polymer terminal. It is presumed that this is because the depolymerization of the polymer at high temperature is suppressed.

The second production method of the present invention simply comprises a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactam-based monomer (b) in the presence of a phosphorus compound having a chain transfer ability. Includes a step of polymerizing a monomer component.

Examples of the phosphorus compound having a chain transfer ability include hypophosphorous acid, phosphorous acid, or salts or hydrates thereof. These may be used alone or in combination of two or more.
Examples of the salt include alkali metal salts such as potassium salt and sodium salt; alkaline earth metal salts such as calcium salt and magnesium salt; and organic salts such as ammonium salt; and the like. Of these, alkali metal salts are preferable, and sodium salts are more preferable, in that depolymerization at high temperatures can be suppressed and the pyrolysis start temperature is high.
Among them, the phosphorus compounds having the above-mentioned chain transfer ability have high chain transfer ability and are easily introduced into the polymer terminal, and can suppress the depolymerization of the polymer at high temperature, so that hypophosphoric acid (salt) and / Alternatively, phosphoric acid (salt) is preferable, and hypophosphoric acid (salt) is more preferable. In addition, in this specification, "phosphorous acid (salt)" means hypophosphoric acid and / or hypophosphite, and "phosphoric acid (salt)" means phosphorous acid and / or sub-phosphate. Means phosphate.

The phosphorus compound having a chain transfer ability may be present in the reaction system at the start of polymerization, or may be added to the reaction system during the polymerization reaction, but it is easily introduced into the polymer terminal, and the polymerization is carried out. It is preferably present in the reaction system at the start.
Further, the phosphorus compound having a chain transfer ability may be added in a batch or sequentially in the total amount to be used, but it is preferable to add the phosphorus compound in a batch because it is easily introduced into the polymer terminal.

The amount of the phosphorus compound having a chain transfer ability is preferably 0.01 to 3 parts by mass with respect to 100 parts by mass of the total amount of the monomer components. When the addition amount of the phosphorus compound having a chain transfer ability is within the above range, it is easy to be introduced into the polymer terminal, the molecular weight of the polymer can be adjusted, the amount of residual monomers and the amount of by-products can be further reduced. The polymer can be produced more efficiently.
The amount of the phosphorus compound having a chain transfer ability is more preferably 0.05 parts by mass or more, still more preferably 0.1 parts by mass or more, based on 100 parts by mass of the total amount of the monomer components. It is more preferably 2 parts by mass or less, and further preferably 1 part by mass or less.

In the second production method of the present invention, the total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) is 100% by mass based on the total amount of the monomer components. It is 85% by mass or more. When the total amount of the monomer (a) and the monomer (b) occupies the above range in the total amount of the monomer components, an N-vinylamide polymer having excellent heat resistance can be obtained. The total content ratio of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactum-based monomer (b) is the total mass of the monomer components in that a polymer having even better heat resistance can be obtained. It is preferably 88% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, and particularly preferably 100% by mass with respect to 100% by mass.

In the second production method of the present invention, the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) are used in the above-mentioned first production method of the present invention. Examples thereof include the same as the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) used. Examples of the content ratio of the monomer (a) and the monomer (b) include the same content ratio as that of the first production method of the present invention described above.

In the second production method of the present invention, the monomer component may further contain another monomer (c) in addition to the above-mentioned monomer (a) and monomer (b).
Examples of the other monomer (c) include those similar to the other monomer (c) used in the above-mentioned first production method of the present invention.
Examples of the content ratio of the monomer (c) include the same content ratio as the other monomer (c) used in the above-mentioned first production method of the present invention.

The polymerization reaction in the polymerization step in the second production method of the present invention is not particularly limited except that the polymerization is carried out in the presence of the phosphorus compound having a chain transfer ability, and radical polymerization is carried out using a polymerization initiator or the like. It can be carried out by a known method such as, and can be carried out in the same manner by using the polymerization initiator, the polymerization solvent and other components described in the above-mentioned first production method of the present invention. Further, the polymerization conditions such as the polymerization temperature, the polymerization time, and the atmosphere can be the same as the conditions described in the first production method of the present invention. The method for mixing the monomer components may be the same as the method described in the above-mentioned first production method of the present invention.

The second manufacturing method of the present invention may have other steps in addition to the above-mentioned steps. Examples thereof include an aging step, a neutralization step, a deactivation step of a polymerization initiator and the like, a dilution step, a concentration step, a purification step and the like. These steps can be performed by a known method. Further, the order of these steps can also be appropriately selected by a known method.

In the above-mentioned first and second production methods of the present invention, the monomer reaction rate is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more.
The monomer reaction rate is determined by determining the amount of various residual monomers by a method such as a gas chromatograph, a liquid chromatograph, or a gel permeation chromatograph that can measure the amount of residual monomers in the polymer, and calculating the total amount of residual monomers from the total amount of monomers. It can be obtained by subtracting the total amount of reaction monomers and calculating the ratio of the total amount of reaction monomers to the total amount of monomers.

2. 2. N-vinylamide-based polymer According to the first and second production methods of the present invention described above, the structural unit derived from the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactum-based monomer (b). ), And the total content ratio of the structural unit derived from the cyclic N-vinylamide-based monomer (a) and the structural unit derived from the N-vinylcaprolactum-based monomer (b) is the total structure. A polymer (copolymer) having an amount of 85% by mass or more with respect to 100% by mass of the unit can be obtained.
In addition, the polymer obtained by the above-mentioned first production method of the present invention has a terminal structure derived from the above-mentioned alcohol solvent. On the other hand, the polymer obtained by the second production method of the present invention has a terminal structure derived from the above-mentioned phosphorus compound having a chain transfer ability. Polymers having such a specific terminal structure are extremely excellent in heat resistance. Such a polymer is also one of the present inventions. The polymer of the present invention will be described below.

<First N-vinylamide polymer of the present invention>
The first N-vinylamide-based polymer of the present invention has a structural unit (A) derived from a cyclic N-vinylamide-based monomer and a structural unit (B) derived from an N-vinylcaprolactum-based monomer. The total content ratio of the structural unit (A) derived from the cyclic N-vinylamide-based monomer and the structural unit (B) derived from the N-vinylcaprolactum-based monomer is 85 mass with respect to 100% by mass of the total structural unit. % Or more, and is characterized by having a main chain terminal structure represented by the following general formula (2).

（式中、Ｒ^４は、水素原子、又は、水酸基を有してもよい炭素数１～５のアルキル基を表す。）

(In the formula, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms which may have a hydroxyl group.)

The first N-vinylamide polymer of the present invention has a main chain terminal structure represented by the above general formula (2). The N-vinylamide polymer may have a main chain terminal structure represented by the general formula (2) and a main chain terminal structure represented by the general formula (3) described later.

In the above general formula (2), R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms which may have a hydroxyl group.
Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a tert-butyl group, a sec-butyl group, a pentyl group, and an isopentyl group. , Neopentyl group, sec-pentyl group, 3-pentyl group, tert-pentyl group and the like. Among them, an alkyl group having 1 to 4 carbon atoms is preferable, and a methyl group, an ethyl group, an n-propyl group, and an iso-propyl group are more preferable in that depolymerization of the polymer is suppressed and the heat resistance of the polymer is improved. Ethyl group and iso-propyl group are more preferable, and ethyl group and iso-propyl group are more preferable.
Among them, as the main chain terminal structure represented by the above general formula (2), one in which ^R4 is a hydrogen atom, an ethyl group or an iso-propyl group is preferably mentioned.

The above-mentioned first N-vinylamide-based polymer of the present invention can be obtained by the above-mentioned first production method of the present invention.

<Second N-vinylamide polymer of the present invention>
The second N-vinylamide-based polymer of the present invention has a structural unit (A) derived from a cyclic N-vinylamide-based monomer and a structural unit (B) derived from an N-vinylcaprolactum-based monomer. The total content ratio of the structural unit (A) derived from the cyclic N-vinylamide-based monomer and the structural unit (B) derived from the N-vinylcaprolactum-based monomer is 85 mass with respect to 100% by mass of the total structural unit. % Or more, and is characterized by having a main chain terminal structure represented by the following general formula (3).

（式中、Ｍ^１及びＭ^２は、同一又は異なって、水素原子、又は、金属原子を表す。）

(In the formula, M ¹ and M ² are the same or different and represent a hydrogen atom or a metal atom.)

In the above general formula (3), M ¹ and M ² represent a hydrogen atom or a metal atom, which are the same or different. Examples of the metal atom preferably include alkali metals such as potassium and sodium; alkaline earth metals such as calcium and magnesium, more preferably alkali metals, and further preferably potassium and sodium.
Among them, M ¹ and M ² are preferably alkali metals, more preferably potassium and sodium.
The second N-vinylamide-based polymer of the present invention can be obtained by the above-mentioned second production method of the present invention.

The first N-vinylamide polymer of the present invention and the second N-vinylamide polymer of the present invention (hereinafter, both polymers are collectively referred to as "N-vinylamide polymer of the present invention". The structural unit in)) will be described.

Examples of the structural unit (A) derived from the cyclic N-vinylamide monomer in the N-vinylamide polymer of the present invention include the structural unit derived from the cyclic N-vinylamide monomer (a) described above. More specifically, a structural unit formed by polymerizing the vinyl group of the monomer (a) to form a main chain can be mentioned.
Examples of the structural unit (B) derived from the N-vinylcaprolactam-based monomer in the N-vinylamide-based polymer of the present invention include the structural unit derived from the N-vinylcaprolactum-based monomer (b) described above. More specifically, a structural unit formed by polymerizing the vinyl group of the monomer (b) to form a main chain can be mentioned.

The content ratio of the structural unit (A) is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, based on 100% by mass of the total structural unit of the N-vinylamide polymer. , 20-85% by mass, more preferably.
The content ratio of the structural unit (B) is preferably 5 to 95% by mass, more preferably 10 to 90% by mass, based on 100% by mass of the total structural unit of the N-vinylamide polymer. , 15-80% by mass, more preferably.

The total content ratio of the structural units (A) and (B) is 85% by mass or more with respect to 100% by mass of all structural units. The total content ratio of the structural units (A) and (B) is preferably 88% by mass or more, preferably 90% by mass or more, in that the heat resistance of the N-vinylamide polymer is further excellent. Is more preferable, 95% by mass or more is further preferable, and 100% by mass is particularly preferable.

The content ratio of the structural units (A) and (B) is preferably 95/5 to 30/70 in terms of mass ratio, and 90 in terms of further increasing the heat resistance of the N-vinylamide polymer. It is more preferably / 10 to 40/60, and even more preferably 85/15 to 50/50.

The N-vinylamide polymer of the present invention may have another structural unit (C) in addition to the above structural unit (A) and structural unit (B). Examples of the other structural unit (C) include structural units derived from the other monomer (c) described above.

The content ratio of the structural unit (C) is preferably 0 to 15% by mass, more preferably 0 to 12% by mass, and 0 to 10% by mass with respect to 100% by mass of all structural units. It is even more preferably 0 to 5% by mass, and even more preferably 0 to 5% by mass.

The glass transition temperature (Tg) of the N-vinylamide polymer of the present invention is preferably 80 ° C. or higher. When the glass transition temperature is 80 ° C. or higher, it becomes easy to produce a dried product of the N-vinylamide polymer.
The glass transition temperature (Tg) of the N-vinylamide polymer is more preferably 100 ° C. or higher, further preferably 120 ° C. or higher. The upper limit of the glass transition temperature (Tg) is preferably 400 ° C. or lower, more preferably 350 ° C. or lower.
The glass transition temperature (Tg) can be determined by a method conforming to the Japanese Industrial Standard JIS K 7121, and specifically, a differential scanning calorimeter (for example, manufactured by Rigaku, Thermo plus EVO DSC-8230, or Netch). , DSC-3500), using α-alumina as a reference, and in a nitrogen gas atmosphere, raise the temperature of a sample of about 10 mg from room temperature to 200 ° C or 240 ° C (heating rate 20 ° C / min) (heating rate 20 ° C / min). The temperature can be obtained from the DSC curve obtained by adjusting the temperature according to the glass transition temperature (Tg) by a method of evaluation by the starting point method.

The weight average molecular weight of the N-vinylamide polymer may be appropriately set according to the purpose and use of the polymer, but is preferably 1000 or more, more preferably 5000 or more, and more preferably 10,000 or more. It is more preferably 1500,000 or less, more preferably 1,000,000 or less, further preferably 800,000 or less, still more preferably 500,000 or less.
The weight average molecular weight can be determined by a gel permeation chromatography (GPC) method, and specifically, can be determined by the method described in Examples described later.

The K value of the N-vinylamide polymer is preferably 15 to 62, more preferably 20 to 60, in that the heat resistance of the polymer is good and the viscosity can be in an appropriate range. , 20-55, more preferably 25-50.
Here, the K value of the N-vinylamide-based polymer is a viscosity characteristic value that correlates with the molecular weight of the N-vinylamide-based polymer, and is calculated by applying it to the following Fikenscher's formula.
K = (1.5logη _rel -1) / (0.15 + 0.003c) + (300logη _rel + (c + 1.5logη _rel ) ² ) ^1/2 / (0.15c + 0.003c ² )
Here, η _rel is the relative viscosity (25 ° C.) of the N-vinylamide-based polymer aqueous solution with respect to water measured by a capillary viscometer, and c is the N-vinylamide-based in the N-vinylamide-based polymer aqueous solution. The concentration of the polymer [% by mass].

The amount of by-products in the N-vinylamide polymer is preferably 1.5% by mass or less, more preferably 1% by mass or less, still more preferably 0.8% by mass or less. It is particularly preferably 0.5% by mass or less.
For example, when N-vinyl-2-pyrrolidone is used as the N-vinyllactam-based monomer, 2-pyrrolidone can be produced as a by-product. When N-vinyl-ε-caprolactam is used as the N-vinylcaprolactam-based monomer, ε-caprolactam can be produced as a by-product.
The amount of the by-product may be appropriately selected from known methods depending on the by-product to be produced. For example, in the case of 2-pyrrolidone or ε-caprolactam, a gas chromatograph, a liquid chromatograph, a gel permeation chromatograph, etc. The by-product in the polymer can be determined by a measurable method, and specifically, can be determined by the method described in Examples.

The amount of residual monomer in the N-vinylamide polymer is preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.5% by mass or less, and 0. It is even more preferably 2% by mass or less, and particularly preferably 0.1% by mass or less.
The amount of the residual monomer can be determined by a method such as a gas chromatograph, a liquid chromatograph, a gel permeation chromatograph or the like in which the amount of the residual monomer in the polymer can be measured. It can be obtained by the method described in.

The thermal decomposition start temperature of the N-vinylamide polymer is preferably 290 ° C. or higher, more preferably 300 ° C. or higher, further preferably 320 ° C. or higher, and more preferably 340 ° C. or higher. Even more preferable.
The thermal decomposition start temperature can be measured using a thermogravimetric measuring device (dynamic TGA), and specifically, can be obtained by the method described in Examples.

3. 3. Resin composition The N-vinylamide polymer of the present invention can be used alone or in combination with other components as a resin composition. Other components include, for example, resin; coloring material; dispersant; heat resistant agent; leveling agent; inorganic fine particles such as silica fine particles; coupling agent; filler; curing aid; plasticizer; polymerization inhibitor; ultraviolet absorption. Agents; Antioxidants; Matters; Defoamers; Antistatic Agents; Lubricants; Surface Modifiers; Shaking Changers; Shaking Aids; Flame Retardants; Antirusts; Acid Generators; Solvents, etc. .. These can be appropriately selected from known ones and used according to the purpose and use of the resin composition. Further, the amount used can be appropriately set according to the purpose and use of the resin composition.

The method for preparing the resin composition is not particularly limited, and a known method may be used. For example, a method of mixing the above-mentioned N-vinylamide polymer and any of the above-mentioned other components using various known mixers such as blenders, mixers, extrusion type, kneaders, dispersers, kneaders and the like can be mentioned. ..

The resin composition can be formed into known forms such as molten pellets, sheets, films, chips, granules, and powders by molding, pulverizing, or the like. Further, it may be further molded using the resin composition of the present invention to obtain a molded product having a desired shape.
The resin composition can be made into known forms such as melt pellets, sheets, films, chips, granules, and powders by melt-kneading and then molding or pulverizing. Further, it can be further molded using the resin composition of the present invention to obtain a molded product having a desired shape. The molding method is not particularly limited, and examples thereof include known methods such as injection molding, extrusion molding, blow molding, compression molding, and vacuum forming, which may be appropriately selected depending on the intended use of the resin composition. The pulverization method is not particularly limited, and a known method can be used.

Further, the resin composition can be in the form of a coating agent by mixing the N-vinylamide polymer with a solvent. In the case of the form of the coating agent, it is advisable to add a solvent to the resin composition so that the solid content is 3 to 40% by mass, preferably 5 to 30% by mass. The solvent is not particularly limited and may be appropriately selected depending on the composition of the resin composition.
Examples of the method of using the coating agent include a method of applying the coating agent on a substrate and drying, heating or the like to form a coating film on the substrate. The coating, drying and heating may be performed by a known method.

<Use>
The N-vinylamide-based polymer of the present invention and the resin composition containing the above-mentioned N-vinylamide-based polymer have excellent heat resistance. Therefore, it can be suitably used for applications that require heat resistance.
Examples of applications for which heat resistance is required include home appliances, electronic materials, electrical parts, automobile parts, containers, films, housing building materials, and the like.

As described above, the method for producing an N-vinylamide-based polymer of the present invention has a small amount of residual monomers and by-products, and can efficiently produce an N-vinylamide-based polymer. Further, the N-vinylamide polymer obtained by the production method of the present invention has excellent heat resistance and is suitably used for various purposes.

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 mass" and "%" means "% by mass".

Each evaluation of the polymer was carried out by the following method.
<Amount of residual monomer>
The amount of the residual monomer (N-vinylpyrrolidone) in the polymer was quantitatively analyzed by a liquid chromatograph under the following conditions. The measurement was performed on a solution prepared by adjusting the polymer to an appropriate concentration with deionized water, and the measured value was multiplied by a dilution ratio to calculate the amount of residual monomer.
Equipment: Shiseido "NANOSPACE SI-2" (using UV / VIS detector)
Column: Shiseido "CAPCELLPAK C18 UG120 (inner diameter 1.5 mm, length 250 mm)", 40 ° C.
Eluent: Methanol for LC (manufactured by Wako Pure Chemical Industries, Ltd.) / Ultrapure water = 1/24 (mass ratio), sodium 1-heptane sulfonate 0.04% by mass Addition flow rate: 100 μL / min
For the amount of residual monomer (N-vinyl caprolactam) in the polymer, use a gas chromatograph (device: GC-2014 manufactured by Shimadzu Corporation, detector: FID, column: G-100 manufactured by Chemicals Evaluation and Research Institute). Obtained using. The measurement was carried out with respect to a solution in which the polymer was adjusted to an appropriate concentration with methanol, and the measured value was multiplied by a dilution ratio to calculate the amount of residual monomer.

<Amount of by-products>
The amount of by-product (2-pyrrolidone) in the polymer was quantitatively analyzed by a liquid chromatograph under the following conditions. The measurement was performed on a solution prepared by adjusting the polymer to an appropriate concentration with deionized water, and the measured value was multiplied by a dilution ratio to calculate the amount of residual monomer.
Equipment: Shiseido "NANOSPACE SI-2" (using UV / VIS detector)
Column: Shiseido "CAPCELLPAK C18 UG120 (inner diameter 1.5 mm, length 250 mm)", 40 ° C.
Eluent: Methanol for LC (manufactured by Wako Pure Chemical Industries, Ltd.) / Ultrapure water = 1/24 (mass ratio), sodium 1-heptane sulfonate 0.04% by mass Addition flow rate: 100 μL / min
For the amount of by-product (ε-caprolactam) in the polymer, use a gas chromatograph (device: GC-2014 manufactured by Shimadzu Corporation, detector: FID, column: G-100 manufactured by Chemicals Evaluation and Research Institute). Obtained using. The measurement was carried out with respect to a solution in which the polymer was adjusted to an appropriate concentration with methanol, and the measured value was multiplied by a dilution ratio to calculate the amount of residual monomer.

<Weight average molecular weight (Mw)>
The weight average molecular weight of the polymer was measured and determined by the gel permeation chromatography (GPC) method under the following conditions.
Equipment: Tosoh HLC-8320GPC
Detector: RI
Column: Showa Denko KD-806M (2 pcs), KD-G 4A
Column temperature: 40 ° C
Flow velocity: 0.8 ml / min
Calibration curve: Polystyrene Standards
Eluent: N, N-dimethylformamide (containing 0.1% LiBr)

<K value>
As for the K value of the polymer, a polymer aqueous solution having a solid content of 1% was prepared, and the viscosity at 25 ° C. was measured by a capillary viscometer manufactured by LAUDA (diluted Micro Ubbelohde viscometer I (K = 0.01)). ), And applied to the above-mentioned Viscoscher's formula to calculate.

<Pyrolysis start temperature>
A TGA curve (rising) obtained by heating a sample of about 10 mg from room temperature to 500 ° C. under an Air atmosphere using a thermogravimetric analyzer (Dynamic TGA) (manufactured by Rigaku, differential thermal balance Thermo plus EVO TG-8120). The temperature at which the weight decreases by 5% / ° C. or more (thermogravimetric start temperature of the copolymer) was determined from (excluding the weight loss due to volatilization of the solvent or the like immediately after the start of warming).

(Example 1)
A 1L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket, 467.5 g of deionized water, 2-propanol (manufactured by Wako Pure Chemical Industries, Ltd., below). , Also referred to as "IPA") 26.0 g was charged. Dissolved oxygen was removed by nitrogen substitution at 200 ml / min for 30 minutes with stirring at 200 rpm. Next, the nitrogen introduction was adjusted to 30 ml / min, and the reactor was heated so that the jacket temperature of the reactor was 85 ° C. (internal temperature was constant at 83 ° C.) while stirring at 200 rpm. Next, while maintaining the jacket temperature of 85 ° C., 120.0 g of N-vinylpyrrolidone (manufactured by Nippon Catalyst Co., Ltd., hereinafter also referred to as “VP”) was used for 180 minutes for N-vinylcaprolactam (manufactured by Tokyo Kasei Kogyo Co., Ltd., hereinafter. , "VCap") 80% IPA solution 150.0 g for 180 minutes, 2,2'-azobis (2-methylpropionamidine) dihydrochloride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., hereinafter "V-" 38.4 g of a 5% aqueous solution (also referred to as “50”) was added dropwise over 210 minutes to initiate polymerization. The amount of total VCap for all VPs was 100% and the amount of V-50 for all monomers (VP + VCap) was 0.8%.
After the completion of the dropping of V-50, the jacket temperature was further maintained at 85 ° C. for 90 minutes to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was concentrated by an evaporator, IPA was removed, and then dried in a heated surface contact type dryer (surface temperature 140 ° C.) for 40 seconds. The obtained dried product was pulverized and classified until it passed through a JIS standard sieve having an opening of 500 μm to obtain a VP / VCap polymer (powder).
The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

(Example 2)
519.5 g of deionized water and 15.6 g of IPA were charged into a 1 L reactor (manufactured by SUS304) equipped with a Max Blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket. Dissolved oxygen was removed by nitrogen substitution at 200 ml / min for 30 minutes with stirring at 200 rpm. Next, the nitrogen introduction was adjusted to 30 ml / min, and the reactor was heated so that the jacket temperature of the reactor was 85 ° C. (internal temperature was constant at 83 ° C.) while stirring at 200 rpm. Then, while maintaining the jacket temperature of 85 ° C., VP 80.0 g was added dropwise over 180 minutes, VCap 80% IPA solution 233.3 g was added dropwise over 180 minutes, and V-50 5% aqueous solution 342.7 g was added dropwise over 210 minutes. Polymerization was started. The amount of total VCap for all VPs was 233% and the amount of V-50 for all monomers (VP + VCap) was 0.8%.
After the completion of the dropping of V-50, 2.7 g of a 10% aqueous solution of V-50 was added, and 30 minutes later, the same amount of a 10% aqueous solution of V-50 was added, and the mixture was held at a jacket temperature of 85 ° C. for 60 minutes. Then, a VP / VCap polymer solution was obtained.
The obtained VP / VCap polymer solution was concentrated by an evaporator, IPA was removed, and then dried in a heated surface contact type dryer (surface temperature 140 ° C.) for 40 seconds. The obtained dried product was pulverized and classified until it passed through a JIS standard sieve having an opening of 500 μm to obtain a VP / VCap polymer (powder).
The constituent monomer ratio of the obtained polymer was VP / VCap = 30/70 (mass ratio).

(Example 3)
166.1 g of deionized water and 201.4 g of IPA were charged into a 1 L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket. Dissolved oxygen was removed by nitrogen substitution at 200 ml / min for 30 minutes with stirring at 200 rpm. Next, the nitrogen introduction was adjusted to 30 ml / min, and the reactor was heated so that the jacket temperature of the reactor was 85 ° C. (internal temperature was constant at 83 ° C.) while stirring at 200 rpm. Then, while maintaining the jacket temperature of 85 ° C., 250.0 g of VP was added dropwise over 180 minutes, 34.7 g of 80% IPA solution of VCap was added dropwise over 180 minutes, and 44.4 g of a 5% aqueous solution of V-50 was added dropwise over 210 minutes. Polymerization was started. The amount of total VCap for all VPs was 11% and the amount of V-50 for all monomers (VP + VCap) was 0.8%.
After the completion of the dropping of V-50, the jacket temperature was further maintained at 85 ° C. for 90 minutes to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was concentrated by an evaporator, and after 2 hours of vacuum drying at 90 ° C. and 2 hours of vacuum drying at 100 ° C. A coalescence (powder) was obtained.
The constituent monomer ratio of the obtained polymer was VP / VCap = 90/10 (mass ratio).

(Example 4)
A 1L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket, 467.5 g of deionized water, and ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. ethanol (99. 5), hereinafter also referred to as "EtOH") 26.0 g was charged. Dissolved oxygen was removed by nitrogen substitution at 200 ml / min for 30 minutes with stirring at 200 rpm. Next, the nitrogen introduction was adjusted to 30 ml / min, and the reactor was heated so that the jacket temperature of the reactor was 80 ° C. (internal temperature was constant at 78 ° C.) while stirring at 200 rpm. Then, while maintaining the jacket temperature of 80 ° C., 120.0 g of VP was added dropwise over 180 minutes, 150.0 g of 80% EtOH solution of VCap was added dropwise over 180 minutes, and 38.4 g of a 5% aqueous solution of V-50 was added dropwise over 210 minutes. Polymerization was started. The amount of total VCap for all VPs was 100% and the amount of V-50 for all monomers (VP + VCap) was 0.8%.
After completion of the dropping of V-50, the mixture was further kept at a jacket temperature of 80 ° C. for 90 minutes to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was concentrated by an evaporator, and after 2 hours of vacuum drying at 90 ° C. and 2 hours of vacuum drying at 100 ° C. A coalescence (powder) was obtained.
The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

(Example 5)
202.9 g of deionized water and 208.3 g of EtOH were charged into a 1 L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket. Dissolved oxygen was removed by nitrogen substitution at 200 ml / min for 30 minutes with stirring at 200 rpm. Next, the nitrogen introduction was adjusted to 30 ml / min, and the reactor was heated so that the jacket temperature of the reactor was 80 ° C. (internal temperature was constant at 78 ° C.) while stirring at 200 rpm. Then, while maintaining the jacket temperature of 80 ° C., 100.0 g of VP was added dropwise over 180 minutes, 125.0 g of 80% EtOH solution of VCap was added over 180 minutes, and 32.0 g of a 5% aqueous solution of V-50 was added dropwise over 210 minutes. Polymerization was started. The amount of total VCap for all VPs was 100% and the amount of V-50 for all monomers (VP + VCap) was 0.8%.
After completion of the dropping of V-50, the mixture was further kept at a jacket temperature of 80 ° C. for 90 minutes to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was concentrated by an evaporator, and after 2 hours of vacuum drying at 90 ° C. and 2 hours of vacuum drying at 100 ° C. A coalescence (powder) was obtained.
The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

(Example 6)
A 1L reactor (manufactured by SUS304) equipped with a Max Blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket was charged with 16.3 g of deionized water and 395.0 g of EtOH from which dissolved oxygen was removed by nitrogen substitution. .. While stirring at 200 rpm, the reactor was heated so that the jacket temperature was 80 ° C. (internal temperature was constant at 78 ° C.). Then, while maintaining the jacket temperature of 80 ° C., VP 100.0 g for 180 minutes and VCap 80% EtOH solution 125.0 g for 180 minutes, dimethyl 2,2'-azobis (2-methylpropionate) (Fuji film sum). 32.0 g of a 5% EtOH solution manufactured by Kojunyaku Co., Ltd. (hereinafter, also referred to as “V-601”) was added dropwise over 210 minutes to initiate polymerization. The amount of total VCap for all VPs was 100% and the amount of V-601 for all monomers (VP + VCap) was 0.8%.
After completion of the dropping of V-601, the jacket temperature was further maintained at 80 ° C. for 90 minutes to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was concentrated by an evaporator, and after 2 hours of vacuum drying at 90 ° C. and 2 hours of vacuum drying at 100 ° C. A coalescence (powder) was obtained.
The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

(Example 7)
411.3 g of IPA was charged into a 1 L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket. While stirring at 200 rpm, the reactor was heated so that the jacket temperature was 85 ° C. (internal temperature was constant at 83 ° C.). Then, while maintaining the jacket temperature of 85 ° C., 100.0 g of VP was dropped over 180 minutes, 125.0 g of 80% IPA solution of VCap was dropped over 180 minutes, and 32.0 g of 5% IPA solution of V-601 was dropped over 210 minutes. The polymerization was started. The amount of total VCap for all VPs was 100% and the amount of V-601 for all monomers (VP + VCap) was 0.8%.
After completion of the dropping of V-601, the jacket temperature was further maintained at 85 ° C. for 90 minutes to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was concentrated by an evaporator, and after 2 hours of vacuum drying at 90 ° C. and 2 hours of vacuum drying at 100 ° C. A coalescence (powder) was obtained.
The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

(Example 8)
A 1L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a perfusion tube, and a jacket, 404.4 g of deionized water, and 1% of diethanolamine (manufactured by Wako Pure Chemical Industries, Ltd.). 2.3 g of an aqueous solution and 0.75 g of sodium hypophosphite (sodium phosphinate monohydrate manufactured by Wako Pure Chemical Industries, Ltd., hereinafter also referred to as "SHP") were charged. Dissolved oxygen was removed by nitrogen substitution at 200 ml / min for 30 minutes with stirring at 200 rpm. Next, the nitrogen introduction was adjusted to 30 ml / min, and the reactor was heated to 90 ° C. while stirring at 200 rpm. Then, while maintaining 90 ° C., 300 parts of a mixed solution of VP and VCap (150 parts of VP and 150 parts of VCap were mixed) was dropped over 180 minutes, and 48.0 g of a 5% aqueous solution of V-50 was dropped over 210 minutes to polymerize. Was started. The amount of total VCap for all VPs was 100% and the amount of V-50 for all monomers (VP + VCap) was 0.8%.
After completion of dropping V-50, the mixture was held at 90 ° C. for 90 minutes to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was dried for 40 seconds in a heated surface contact type dryer (surface temperature 140 ° C.). The obtained dried product was pulverized and classified until it passed through a JIS standard sieve having an opening of 500 μm to obtain a VP / VCap polymer (powder).
The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

(Comparative Example 1)
559 parts of ethyl acetate (manufactured by Wako Pure Chemical Industries, Ltd.) was charged into a 1L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket. The reactor was heated to 75 ° C. with stirring at 250 rpm. Then, while maintaining 75 ° C., 38.6 parts of 82% ethyl acetate solution, 55 parts, 2,2'-azobis (2-methylbutyronitrile) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., hereinafter, "V". 10.8 parts of a 5% ethyl acetate solution (also referred to as −59 ”) was added dropwise over 30 minutes. Then, while maintaining 75 ° C., 96.4 parts of VP took 180 minutes, 110 parts of 82% ethyl acetate solution of VCap took 150 minutes, and 32.4 parts of 5% ethyl acetate solution of V-59 took 210 minutes, respectively. Dropped. The amount of total VCap for all VPs was 100% and the amount of V-59 for all monomers (VP + VCap) was 0.8%.
After 300 minutes from the start of dropping VP, 33.2 parts of IPA was added in a batch to obtain a VP / VCap polymer solution.
The obtained VP / VCap polymer solution was vacuum dried at 90 ° C. for 4 hours, pulverized until it passed through a JIS standard sieve having a mesh size of 500 μm, and the powder was vacuum dried at 150 ° C. for 8 hours to obtain a VP / VCap weight. A coalescence (powder) was obtained. The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

(Comparative Example 2)
637.4 parts of deionized water was charged into a 1L reactor (manufactured by SUS304) equipped with a max blend type stirring blade (manufactured by SUS304), a thermometer, a reflux tube, and a jacket. Nitrogen substitution was performed at 200 mL / min for 30 minutes with stirring at 250 rpm to remove dissolved oxygen. Next, the nitrogen introduction was adjusted to 30 ml / min, and the reactor was heated to 90 ° C. with stirring at 250 rpm. Then, while maintaining 90 ° C., 280 parts of the mixed solution of VP and VCap (140 parts of VP and 140 parts of VCap were mixed) was added dropwise over 180 minutes, and 16.8 parts of the 5% aqueous solution of V-50 was added dropwise over 210 minutes. .. The amount of total VCap for all VPs was 100% and the amount of V-50 for all monomers (VP + VCap) was 0.3%.
After completion of the dropping of V-50, the mixture was further held at 90 ° C. for 90 minutes to obtain a VP / VCap polymer aqueous solution.
The obtained VP / VCap aqueous solution was dried for 40 seconds in a heated surface contact type dryer (surface temperature 140 ° C.). The obtained dried sheet was pulverized until it passed through a JIS standard sieve having an opening of 500 μm to obtain a VP / VCap polymer (powder).
The constituent monomer ratio of the obtained polymer was VP / VCap = 50/50 (mass ratio).

For the polymers obtained in the above Examples and Comparative Examples, the amount of residual monomer, the amount of by-products (amount of 2-pyrrolidone produced, the amount of ε-caprolactam produced), the weight average molecular weight, and the thermal decomposition start temperature were evaluated by the above method. did. The results obtained are shown in Table 1.

From Table 1, in the case of using an alcohol solvent as the polymerization solvent in the polymerization of the cyclic N-vinylamide-based monomer and the N-vinylcaprolactum-based monomer (Examples 1 to 7), the other case is used. It was confirmed that a polymer having a small amount of residual monomers and by-products and excellent heat resistance can be obtained as compared with the case where only an organic solvent or water is used (Comparative Examples 1 and 2).
Further, when the alcohol-based solvent and water are used in combination as the polymerization solvent (Examples 1 to 6), the amount of residual monomers and the amount of by-products are larger than those in the case of using only the alcohol-based solvent (Example 7). It was confirmed that an excellent polymer could be obtained with less heat resistance.
Furthermore, when a phosphorus compound having a chain transfer ability is used (Example 8), the amount of residual monomers and by-products is smaller than that when the chain transfer ability is not used (Comparative Example 2), and the heat resistance is improved. It was confirmed that an excellent polymer could be obtained.

Claims (8)

A step of polymerizing a monomer component containing a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactam-based monomer (b) in a polymerization solvent containing an alcohol-based solvent is included.
The total content of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) is 85% by mass or more with respect to 100% by mass of the total amount of the monomer components. A method for producing an N-vinylamide polymer. The method for producing an N-vinylamide polymer according to claim 1, wherein the alcohol solvent has a boiling point of 100 ° C. or lower. The method for producing an N-vinylamide-based polymer according to claim 1 or 2, wherein the polymerization solvent further contains water. The method for producing an N-vinylamide-based polymer according to claim 3, wherein the polymerization solvent has a mass ratio of an alcohol solvent to water of 95/5 to 5/95. Including the step of polymerizing a monomer component containing a cyclic N-vinylamide-based monomer (a) and an N-vinylcaprolactam-based monomer (b) in the presence of a phosphorus compound having a chain transfer ability.
The total content of the cyclic N-vinylamide-based monomer (a) and the N-vinylcaprolactam-based monomer (b) is 85% by mass or more with respect to 100% by mass of the total amount of the monomer components. A method for producing an N-vinylamide polymer. The method for producing an N-vinylamide polymer according to claim 5, wherein the phosphorus compound having a chain transfer ability is hypophosphoric acid (salt) and / or phosphoric acid (salt). It has a structural unit (A) derived from a cyclic N-vinylamide-based monomer and a structural unit (B) derived from an N-vinylcaprolactam-based monomer.
The total content ratio of the structural unit (A) derived from the cyclic N-vinylamide-based monomer and the structural unit (B) derived from the N-vinylcaprolactam-based monomer is 85% by mass with respect to 100% by mass of the total structural unit. % Or more,
An N-vinylamide-based polymer having a main chain terminal structure represented by the following general formula (2).

(In the formula, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms which may have a hydroxyl group.) It has a structural unit (A) derived from a cyclic N-vinylamide-based monomer and a structural unit (B) derived from an N-vinylcaprolactam-based monomer.
The total content ratio of the structural unit (A) derived from the cyclic N-vinylamide-based monomer and the structural unit (B) derived from the N-vinylcaprolactam-based monomer is 85% by mass with respect to 100% by mass of the total structural unit. % Or more,
An N-vinylamide-based polymer having a main chain terminal structure represented by the following general formula (3).

(In the formula, M ¹ and M ² are the same or different and represent a hydrogen atom or a metal atom.)