JP2023093385A - Polymer production method and resin composition - Google Patents

Abstract

To provide a method for efficiently producing an N-alkylmaleimide-based polymer having excellent optical characteristics, heat resistance and mechanical strength.SOLUTION: A method for producing an N-alkylmaleimide-based polymer includes suspension-polymerizing a monomer mixture comprising 20-100 wt.% of an N-alkylmaleimide represented by the following general formula (1) and 0-80 wt.% of other copolymerizable monomer, using an oil-soluble radical polymerization initiator, in an aqueous medium, in the presence of one or more dispersants selected from the group consisting of a nonionic compound which is coupled to oxygen or nitrogen and has no hydrogen, a polyacrylic acid salt and polyalkylene glycol. In the general formula (1), R represents a straight-chain alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing an N-alkylmaleimide polymer and a resin composition, and more particularly to an efficient production of an N-alkylmaleimide polymer having excellent optical properties, heat resistance and mechanical strength. and a resin composition containing an N-alkylmaleimide polymer.

Homopolymers or copolymers (N-alkylmaleimide-based polymers) obtained from N-alkylmaleimides exhibit higher heat resistance than general thermoplastic vinyl polymers, and are resins with excellent transparency. It is known to become Therefore, N-alkylmaleimide-based polymers are promising materials as transparent resins that can be used in various applications in the optical field (see, for example, Non-Patent Document 1).

N-alkylmaleimide-based polymers, including alternating copolymers of N-alkylmaleimides and vinyl aromatic hydrocarbons such as styrene, have a simple composition, low birefringence, and can be used under a wide range of environmental temperatures. It has been reported that a polymer material that can maintain low birefringence can be realized (see, for example, Patent Document 1).

N-alkylmaleimide-based polymers can be produced by radical polymerization. Moreover, the manufacturing method can be manufactured by a conventionally known method such as bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization. However, bulk polymerization has the problem that it is difficult to remove heat and that it is difficult to remove unreacted monomers, requiring special production equipment. Moreover, in the emulsion polymerization, it is difficult to remove the emulsifier, and there is a problem that the transparency of the polymer is impaired. The problem with solution polymerization is that the resulting polymer has a relatively low molecular weight and does not have sufficient mechanical strength. On the other hand, suspension polymerization is an industrially preferable production method because it is easy to control the temperature of the polymerization system, it is possible to obtain a polymer with a high molecular weight, and it is relatively easy to remove the monomer after polymerization. is. However, even in suspension polymerization, it is difficult to remove the dispersant, and there is a problem that the transparency of the polymer is impaired.

In contrast, suspension polymerization using water-soluble celluloses as a dispersant has been proposed as a method for producing an N-alkylmaleimide polymer having excellent transparency (see, for example, Patent Documents 2 and 3).

JP 2020-126229 A JP 2009-102495 A JP 2009-215346 A

Takayuki Otsu, "Miraizai", Vol. 3, No. 1, pages 74-79

However, even suspension polymerization using water-soluble celluloses as a dispersing agent is still unsatisfactory, and further improvement is desired.

The present invention has been made in view of the above problems, and provides a method for efficiently producing an N-alkylmaleimide polymer having excellent optical properties, heat resistance and mechanical strength, and related techniques. is.

In order to solve the above problems, the present inventors have made intensive studies, and as a result, have found a method for producing an N-alkylmaleimide polymer by suspension polymerization using a specific dispersant, and have completed the present invention. .

ここで、Ｒは炭素数１～１２の直鎖状アルキル基、炭素数３～１２の分岐状アルキル基または炭素数３～６の環状アルキル基を示す。 That is, in embodiment 1 of the present invention, a monomer mixture comprising 20 to 100% by weight of an N-alkylmaleimide represented by the following general formula (1) and 0 to 80% by weight of other copolymerizable monomers, An oil-soluble radical polymerization initiator is used in the presence of at least one dispersant selected from the group consisting of nonionic compounds having no hydrogen bound to oxygen or nitrogen, polyacrylates, and polyalkylene glycols. The present invention relates to a method for producing an N-alkylmaleimide polymer characterized by suspension polymerization in an aqueous medium.

Here, R represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.

In the production method according to aspect 2 of the present invention, in addition to the configuration of aspect 1 described above, R is a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. , hexyl group, cyclohexyl group or octyl group.

In the production method according to aspect 3 of the present invention, in addition to the configuration of aspect 1 or 2 described above, the other copolymerizable monomer is a vinyl aromatic hydrocarbon, an olefin, an alkyl acrylate, or an alkyl methacrylate. ester or carboxylic acid vinyl ester.

In the production method according to aspect 4 of the present invention, in addition to the configuration of any one of aspects 1 to 3 described above, the dispersant is at least one selected from the group consisting of polyvinylpyrrolidone, sodium polyacrylate and polyethylene glycol. That's it.

In the production method according to aspect 5 of the present invention, in addition to the configuration of any one of aspects 1 to 4 described above, the N-alkylmaleimide polymer has a weight average molecular weight of 200,000 to 2,000,000. .

In the production method according to aspect 6 of the present invention, in addition to the configuration of any one of aspects 1 to 5 described above, after filtering the N-alkylmaleimide polymer obtained by suspension polymerization, N-alkylmaleimide Washing the N-alkylmaleimide polymer with a solvent that dissolves the dispersant without dissolving the N-alkylmaleimide polymer, and dissolving unreacted monomers without dissolving the N-alkylmaleimide polymer. Further comprising washing the N-alkylmaleimide polymer with a solvent.

ここで、Ｒは炭素数１～１２の直鎖状アルキル基、炭素数３～１２の分岐状アルキル基または炭素数３～６の環状アルキル基を示す。 Further, aspect 7 of the present invention is an N- 100 parts by weight of an alkylmaleimide polymer and 2 parts by weight of at least one dispersant selected from the group consisting of nonionic compounds having no hydrogen bound to oxygen or nitrogen, polyacrylates, and polyalkylene glycols part or less.

Here, R represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.

By the production method of the present invention, an N-alkylmaleimide polymer excellent in optical properties, heat resistance and mechanical strength can be efficiently produced.

Each aspect of the present invention will be described in detail below. In this specification, the numerical range indicated using "-" indicates the range including the numerical values described before and after "-" as the minimum and maximum values, respectively.

一般式（１）のＲは炭素数１～１２の直鎖状アルキル基、炭素数３～１２の分岐状アルキル基または炭素数３～６の環状アルキル基を示す。 <Method for producing N-alkylmaleimide polymer>
A method for producing an N-alkylmaleimide-based polymer according to one aspect of the present invention comprises: 20 to 100% by weight of an N-alkylmaleimide represented by the following general formula (1) and 0 to 80% by weight of other copolymerizable monomers; % of the monomer mixture in the presence of at least one dispersant selected from the group consisting of nonionic compounds having no hydrogen bound to oxygen or nitrogen, polyacrylates, and polyalkylene glycols. Second, suspension polymerization is carried out in an aqueous medium using an oil-soluble radical polymerization initiator.

R in the general formula (1) represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.

By the production method according to this embodiment, an N-alkylmaleimide polymer excellent in optical properties, heat resistance and mechanical strength can be efficiently produced. Specifically, the film formed using the polymer obtained by the production method according to this aspect has the following advantages compared to the film formed using the polymer obtained by suspension polymerization using a conventional dispersant Excellent mechanical strength and transparency. In addition, the production method according to this aspect performs suspension polymerization, which is easier to operate than bulk polymerization. It has excellent optical properties (transparency, low birefringence), heat resistance and mechanical strength, similar to the film formed using the polymer obtained by the above. Therefore, compared with bulk polymerization, an N-alkylmaleimide polymer excellent in optical properties, heat resistance and mechanical strength can be produced more efficiently.

Examples of linear alkyl groups having 1 to 12 carbon atoms include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group and dodecyl group. Examples of branched alkyl groups having 3 to 12 carbon atoms include isopropyl group, isobutyl group, sec-butyl group and tert-butyl group. Examples of the cyclic alkyl group having 3 to 6 carbon atoms include cyclopropyl group, cyclobutyl group and cyclohexyl group. Among these, R is preferably a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, hexyl group, cyclohexyl group or octyl group. A methyl group, an ethyl group, an isopropyl group, a tert-butyl group, and a cyclohexyl group are preferred, since the N-alkylmaleimide polymer has more excellent heat resistance. Furthermore, since the safety of N-alkylmaleimide as a compound is high, safety measures on equipment can be reduced, and it can be produced efficiently and economically, R in general formula (1) can be ethyl group, tert-butyl group, and A cyclohexyl group is preferred. The N-alkylmaleimide represented by the general formula (1) may be used alone or in combination of multiple types.

Specific examples of the N-alkylmaleimide represented by the general formula (1) include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N -sec-butylmaleimide, N-tert-butylmaleimide, N-pentylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-decylmaleimide, N-dodecylmaleimide, N-cyclopropylmaleimide, N-cyclobutylmaleimide and N-cyclohexylmaleimide can be exemplified. Among these, N-alkylmaleimides include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-sec-butylmaleimide, N- Tert-butylmaleimide, N-hexylmaleimide, N-cyclohexylmaleimide and N-octylmaleimide are preferred, and N-methylmaleimide, N-methylmaleimide, N- Ethylmaleimide, N-isopropylmaleimide, N-tert-butylmaleimide and N-cyclohexylmaleimide are preferred. Furthermore, N-ethylmaleimide, N-tert-butylmaleimide, and N-cyclohexylmaleimide are further added because they are highly safe as compounds of N-alkylmaleimides, can reduce safety measures in facilities, and can be produced efficiently and economically. preferable.

Other copolymerizable monomers in one aspect of the present invention are not limited as long as they are copolymerizable with N-alkylmaleimide. Examples include vinyl aromatic hydrocarbons such as styrene and α-methylstyrene; olefins such as ethylene, propylene, 1-butene and isobutene; acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate and butyl acrylate; methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate; carboxylic acid vinyl esters such as vinyl acetate, vinyl propionate and vinyl pivalate; Among these, vinyls such as styrene and α-methylstyrene can be realized because they can realize N-alkylmaleimide polymers that have a simple composition, have low birefringence, and can maintain the low birefringence under a wide range of environmental temperatures. Aromatic hydrocarbons; acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate and butyl acrylate; methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate; are preferred, especially styrene and α-methyl Vinyl aromatic hydrocarbons such as styrene; methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate; are preferred. Other copolymerizable monomers may be used alone or in combination of multiple types.

In one embodiment of the present invention, the mixing ratio of the monomer mixture comprising the N-alkylmaleimide represented by the general formula (1) and other copolymerizable monomers is 20 to 100% by weight of the N-alkylmaleimide and other 0 to 80% by weight of copolymerizable monomers, and among them, 35 to 100% by weight of N-alkylmaleimide is preferable because an N-alkylmaleimide polymer having particularly excellent heat resistance and optical properties can be obtained. and 0 to 65% by weight of other copolymerizable monomers, more preferably 50 to 100% by weight of N-alkylmaleimide and 0 to 50% by weight of other copolymerizable monomers. Furthermore, since photoelastic coefficient and intrinsic birefringence are improved, 55 to 80% by weight of N-alkylmaleimide and 20 to 45% by weight of other copolymerizable monomers are particularly preferred.

Dispersants in one aspect of the present invention are nonionic compounds that do not have hydrogen bonded to oxygen or nitrogen. That is, the compound has no hydrogens attached to oxygen and no hydrogens attached to nitrogen. A nonionic compound having no hydrogen bound to oxygen or nitrogen has a weak interaction with the N-alkylmaleimide polymer and can be efficiently removed by washing after polymerization. Since it can be efficiently removed by washing after polymerization, suspension polymerization using the compound yields an N-alkylmaleimide polymer having excellent optical properties and mechanical strength. It has never been reported that transparency and mechanical strength can be improved by using a nonionic compound that does not have hydrogen bonded to oxygen or nitrogen.

Examples of nonionic compounds having no hydrogen bonded to oxygen or nitrogen in one aspect of the present invention include polyoxyethylene alkyl ethers, poly(N-vinylamide), and polyoxypropylene/polyoxyethylene block copolymers. can.

Examples of polyoxyethylene alkyl ethers include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene myristyl ether, and polyoxyethylene octyldodecyl ether.

Examples of poly(N-vinylamide) include poly(N-vinylformamide), poly(N-vinylacetamide), poly(N-vinylisobutyramide), polyvinylpyrrolidone, and polyvinylcaprolactam. Among these, the obtained N-alkylmaleimide polymer is obtained as granular particles, and the poly(N-vinylamide) after polymerization can be removed more efficiently, so that the N- Poly(N-vinylformamide), poly(N-vinylacetamide), and polyvinylpyrrolidone are preferred because they yield alkylmaleimide-based polymers.

When polyvinylpyrrolidone is used as a nonionic compound that does not have hydrogen bound to oxygen or nitrogen, the viscosity characteristic value (K value) calculated by the Fikentscher formula represented by the following formula (2) is preferably 10 to 130. Among them, the particularly obtained N-alkylmaleimide polymer is obtained as granular particles, and the water-soluble poly(N-vinylamide) after polymerization can be removed more efficiently, so that the N- The K value is more preferably 20-125, particularly preferably 30-120, since an alkylmaleimide polymer can be obtained.
K=(1.5×log η _rel −1)/(0.15+0.003×c)+{300×c×log η _rel +(c+1.5×c×log _{η rel} ) ² } 1/ ² /(0. 15×c+0.003×c ² ) (2)
η _rel : Relative viscosity of the polyvinylpyrrolidone aqueous solution to water c: Polyvinylpyrrolidone concentration (%) in the polyvinylpyrrolidone aqueous solution.

Also, the dispersant in one aspect of the present invention is a polyacrylate. Polyacrylate does not have oxygen-bonded hydrogen and nitrogen-bonded hydrogen in the polyacrylic acid main chain except for the cationic portion, and has a weak interaction with the N-alkylmaleimide polymer. , can be efficiently removed by washing after polymerization. Since it can be efficiently removed by washing after polymerization, suspension polymerization using the polyacrylate yields an N-alkylmaleimide polymer having excellent optical properties and mechanical strength. It has not been reported at all that the use of polyacrylate can improve transparency and mechanical strength.

Examples of polyacrylates in one aspect of the present invention include sodium polyacrylate, potassium polyacrylate, calcium polyacrylate, magnesium polyacrylate, and ammonium polyacrylate. Among these, the obtained N-alkylmaleimide polymer is obtained as granular particles, and the polyacrylate after polymerization can be removed more efficiently, so that the N-alkylmaleimide is excellent in optical properties and mechanical strength. Sodium polyacrylate is preferred because it yields a polymer of the same type.

When sodium polyacrylate is used as the polyacrylate, the weight average molecular weight (Mw) of sodium polyacrylate is not particularly limited, but the obtained N-alkylmaleimide polymer is obtained as granular particles, It is preferably from 100,000 to 5,000,000 because it is possible to efficiently remove sodium polyacrylate after polymerization, thereby obtaining an N-alkylmaleimide polymer having excellent optical properties and mechanical strength. It is preferably 500,000 to 3,000,000, particularly preferably 1,000,000 to 3,000,000.

Also, the dispersant in one aspect of the present invention is a polyalkylene glycol. Polyalkylene glycol is a polymer of alkylene oxide having 2 to 4 carbon atoms, and has hydrogen bonded to oxygen, but it has weak interaction with N-alkylmaleimide polymer and can be washed after polymerization. can be removed effectively. Since it can be efficiently removed by washing after polymerization, suspension polymerization using the polyalkylene glycol yields an N-alkylmaleimide polymer having excellent optical properties and mechanical strength. It has not been reported at all that the use of polyalkylene glycol can improve transparency and mechanical strength.

Examples of polyalkylene glycol in one aspect of the present invention include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polyoxyethylene polyoxypropylene glycol. Among these, the obtained N-alkylmaleimide polymer is obtained as granular particles, and the polyalkylene glycol after polymerization can be removed more efficiently, so that the N-alkylmaleimide polymer is superior in optical properties and mechanical strength. Polyethylene glycol is preferred because it yields a polymer.

When polyethylene glycol is used as the polyalkylene glycol, the viscosity-average molecular weight of polyethylene glycol is not particularly limited. It is preferably from 20,000 to 10,000,000, more preferably from 150,000 to 8,000, because an N-alkylmaleimide polymer having excellent optical properties and mechanical strength can be obtained by removing the ,000, particularly preferably 1,000,000 to 5,000,000.

In one aspect of the present invention, the dispersant is one or more selected from the group consisting of nonionic compounds having no oxygen or nitrogen-bonded hydrogen, polyacrylates, and polyalkylene glycols. Only one type of dispersant may be used, or a plurality of types may be mixed and used.

In one aspect of the present invention, the amount of at least one dispersant selected from the group consisting of nonionic compounds having no hydrogen bonded to oxygen or nitrogen, polyacrylates, and polyalkylene glycols is a single amount. 0.01 to 25 parts by weight per 100 parts by weight of the solid mixture is preferred. Among them, the particularly obtained N-alkylmaleimide polymer is obtained as granular particles, and the dispersant after polymerization can be efficiently removed, so that the N-alkylmaleimide polymer having excellent optical properties and mechanical strength can be obtained. Therefore, the amount of the dispersant added is more preferably 0.01 to 20 parts by weight, and particularly preferably 0.01 to 15 parts by weight.

The oil-soluble radical polymerization initiator in one aspect of the present invention includes benzoyl peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide, oxide, tert-butyl peroxyacetate, tert-butyl peroxybenzoate, tert-butyl peroxy-2-ethylhexanoate, tert-hexylperoxy-2-ethylhexanoate, 2,5-dimethyl-2, 5-di(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, tert-butylperoxypivalate, tert-hexylperoxypivalate , organic peroxides such as tert-butyl peroxyneodecanoate and tert-hexyl peroxyneodecanoate, and 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis Azo initiation such as (2-butyronitrile), 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate and 1,1′-azobis(cyclohexane-1-carbonitrile) agents can be exemplified.

In addition, the amount of the oil-soluble radical polymerization initiator to be used can be appropriately set, and is, for example, 0.0001 to 2 parts by weight with respect to 100 parts by weight of the monomer mixture. The amount of the oil-soluble radical polymerization initiator used is preferably 0.001 to 1 part by weight, more preferably 0.01 to 0.5 part by weight, since the system polymer is superior in optical properties and mechanical strength. be.

The aqueous medium in one aspect of the present invention may be one that is usually treated as an aqueous medium, such as water, industrial water, ion-exchanged water, and distilled water. In addition, the amount of the aqueous medium used is, for example, 100 to 500 parts by weight with respect to 100 parts by weight of the monomer mixture. 125 to 400 parts by weight are preferred, and 150 to 300 parts by weight are particularly preferred.

In the production method according to one aspect of the present invention, when the N-alkylmaleimide is in a solid state, the N-alkylmaleimide polymer is efficiently produced by charging the N-alkylmaleimide in a solution state when the monomers are charged. An oily medium may be added for better production. At least one selected from the group consisting of aromatic hydrocarbons, ethers, esters, ketones and halogen compounds can be used as the oily medium.

Here, toluene and xylene can be exemplified as aromatic hydrocarbons. Examples of ethers include diethyl ether and diisopropyl ether. Examples of esters include ethyl acetate, butyl acetate and dimethyl carbonate. Examples of ketones include methyl ethyl ketone and methyl isobutyl ketone. Examples of halogen compounds include chloroform, methylene chloride and 1,2-dichloroethane. Among these, aromatic hydrocarbons, ethers, esters and ketones are preferred, and toluene and xylene are particularly preferred, in order to efficiently produce an N-alkylmaleimide polymer having excellent mechanical strength.

In addition, when an oily medium is added, the amount used may be any amount as long as the production method of the present invention can be carried out. In order to efficiently produce coalescence, it is preferably 0.01 to 70 parts by weight, more preferably 0.1 to 50 parts by weight, and particularly preferably 5 to 25 parts by weight with respect to 100 parts by weight of the monomer mixture. weight part.

The polymerization temperature in one aspect of the production method of the present invention can be appropriately set according to the decomposition temperature of the oil-soluble radical polymerization initiator. For efficient polymer production, the temperature is preferably 40 to 150°C, more preferably 50 to 90°C, and particularly preferably 60 to 80°C.

In the production method according to one aspect of the present invention, in order to efficiently and economically produce a granular N-alkylmaleimide polymer having excellent optical properties and mechanical strength, After filtering the N-alkylmaleimide polymer, washing the N-alkylmaleimide polymer with a solvent that dissolves the dispersant without dissolving the N-alkylmaleimide polymer; It is preferred to include washing the N-alkylmaleimide polymer with a solvent that dissolves unreacted monomer without dissolving the polymer.

The solvent that dissolves the dispersant without dissolving the N-alkylmaleimide polymer may be a solvent that dissolves not only the dispersant but also the unreacted monomers. Similarly, the solvent that dissolves the unreacted monomer without dissolving the N-alkylmaleimide polymer may be a solvent that dissolves not only the unreacted monomer but also the dispersant. That is, the solvent used is one in which the N-alkylmaleimide polymer is insoluble and (i) only the dispersant is soluble, (ii) only the unreacted monomer is soluble, or (iii) the dispersant and the unreacted Solvents in which both monomers are soluble can be mentioned. The solvent is not particularly limited as long as it is such a solvent, and water, methanol, ethanol, a mixed solvent of methanol/toluene, a mixed solvent of ethanol/toluene, a mixed solvent of methanol/water, and a mixed solvent of ethanol/water can be exemplified. For example, water is soluble in dispersant and unreacted N-alkylmaleimide monomer. On the other hand, methanol, ethanol, methanol/toluene mixed solvent, ethanol/toluene mixed solvent, methanol/water mixed solvent, and ethanol/water mixed solvent contain dispersant, unreacted N-alkylmaleimide monomer and unreacted other Copolymerizable monomers are soluble.

If the N-alkylmaleimide polymer is insoluble and both the dispersant and the unreacted monomer are soluble in the solvent, the dispersant and the unreacted monomer can be removed simultaneously with a single solvent. . Alternatively, the dispersant and the unreacted monomer may be separately removed using different solvents. When the dispersant and the unreacted monomer are removed separately, after washing the N-alkylmaleimide polymer with a solvent that dissolves the dispersant, the N-alkylmaleimide polymer is washed with a solvent that dissolves the unreacted monomer. The polymer may be washed, or may be washed with a solvent that dissolves the dispersant after washing with a solvent that dissolves unreacted monomers. In order to efficiently remove the dispersant, from the viewpoint of washing the dispersant while the N-alkylmaleimide polymer is swollen with the unreacted monomer, a solvent that dissolves the dispersant is added to the N-alkylmaleimide polymer. After washing the polymer, it is preferable to wash the N-alkylmaleimide polymer with a solvent that dissolves unreacted monomers.

In one aspect of the present invention, a chain transfer agent such as alkyl mercaptan, or a hindered phenol-based or phosphorus-based antioxidant may be used at the beginning of polymerization, during polymerization, or after polymerization, if necessary.

The weight-average molecular weight (M _w ) of the N-alkylmaleimide polymer obtained by the production method in one aspect of the present invention is not particularly limited, but the N-alkylmaleimide polymer has excellent optical properties and mechanical strength. is preferably 200,000 to 2,000,000, more preferably 500,000 to 1,800,000, and particularly preferably 800,000 to 1,500,000. Incidentally, the weight average molecular weight (M _w ) of the N-alkylmaleimide polymer can be controlled by the polymerization temperature.

In the N-alkylmaleimide-based polymer obtained by the production method according to one aspect of the present invention, the ratio of units derived from N-alkylmaleimide, that is, the ratio of N-alkylmaleimide residues is in the range of 20 to 100% by weight, Among them, the amount is preferably 35 to 100% by weight, more preferably 50 to 100% by weight, because an N-alkylmaleimide polymer having particularly excellent heat resistance and optical properties can be obtained.

Although there is no particular limitation on the particle shape of the N-alkylmaleimide-based polymer obtained by the production method of one embodiment of the present invention, by efficiently removing the dispersant and/or the unreacted monomer, Since an N-alkylmaleimide polymer having excellent optical properties and mechanical strength can be obtained, it is preferably granular and has an average particle size in the range of 20 to 2,000 μm, more preferably an average particle size of 30 μm. to 1,000 μm, and particularly preferably the average particle size is in the range of 50 to 900 μm. The average particle size in this specification is the particle size at which the volume-based cumulative particle amount is 50%, determined by the laser diffraction/scattering method.

The glass transition point (Tg) of the N-alkylmaleimide polymer serves as an index of heat resistance. The glass transition point (Tg) of the N-alkylmaleimide polymer obtained by one embodiment of the production method of the present invention is not particularly limited, but the N-alkylmaleimide polymer having excellent heat resistance can be obtained. , preferably 120° C. or higher, more preferably 135° C. or higher, and particularly preferably 150° C. or higher.

The tensile stress of the N-alkylmaleimide polymer is an index of mechanical strength. The tensile stress of the N-alkylmaleimide polymer obtained in one embodiment of the production method of the present invention is not particularly limited, but is preferably 30 MPa because an N-alkylmaleimide polymer having excellent mechanical strength can be obtained. or more, more preferably 35 MPa or more, and particularly preferably 40 MPa or more. The tensile stress of the N-alkylmaleimide polymer can be controlled by _Mw .

The tensile elongation, which is an index of the mechanical strength of the N-alkylmaleimide polymer obtained by the production method of one embodiment of the present invention, is not particularly limited, but an N-alkylmaleimide polymer having excellent mechanical strength can be obtained. Therefore, it is preferably 1.5% or more, more preferably 2% or more, still more preferably 2.5% or more, and particularly preferably 3% or more.

The haze of an N-alkylmaleimide polymer is one index of optical properties. The haze of the N-alkylmaleimide polymer obtained in one embodiment of the production method of the present invention is not particularly limited, but is preferably 3% because an N-alkylmaleimide polymer having excellent transparency can be obtained. less than, preferably less than 2.5%, particularly preferably less than 2%. The haze of the N-alkylmaleimide polymer can be controlled by the type of dispersant, the amount of residual dispersant in the N-alkylmaleimide polymer, and the amount of residual monomer.

The photoelastic constant (C) and intrinsic birefringence (Δn ⁰ ) of N-alkylmaleimide-based polymers are one index of optical properties. The absolute values of the photoelastic constant (C) and intrinsic birefringence (Δn ⁰ ) of the N-alkylmaleimide polymer obtained in one embodiment of the production method of the present invention are not particularly limited, but Since an N-alkylmaleimide polymer can be obtained, the absolute value of C is preferably 50×10 ⁻¹² Pa ⁻¹ or less and the absolute value of Δn ⁰ is 20×10 ⁻³ or less, and more preferably C The absolute value of C is 10×10 ⁻¹² Pa ⁻¹ or less, and the absolute value of Δn ⁰ is 5×10 ⁻³ or less, and particularly preferably the absolute value of C is 2×10 ⁻¹² Pa ⁻¹ or less, and Δn The absolute value of ⁰ is 1×10 ⁻³ or less. C and Δn ⁰ of the N-alkylmaleimide polymer are constants that can be controlled by the type of monomer and the ratio of monomer units, ie residues, in the N-alkylmaleimide polymer.

The temperature constant (dΔn ⁰ /dT) of the intrinsic birefringence of an N-alkylmaleimide polymer is one index of optical properties. The absolute value of the temperature constant (dΔn ⁰ /dT) of the intrinsic birefringence of the N-alkylmaleimide polymer obtained in one embodiment of the production method of the present invention is not particularly limited, but it is low under a wide range of environmental temperatures. Since an N-alkylmaleimide polymer capable of maintaining birefringence can be obtained, it is preferably 2×10 ⁻⁵ ° C. ⁻¹ or less, more preferably 1×10 ⁻⁵ ° C. ⁻¹ or less. The dΔn ⁰ /dT of the N-alkylmaleimide polymer is a constant that can be controlled by the type of monomer and the ratio of monomer units, ie residues, in the N-alkylmaleimide polymer.

<Resin composition>
The resin composition according to one aspect of the present invention comprises 20 to 100% by weight of N-alkylmaleimide residues represented by the following general formula (1A) and 0 to 80% by weight of other copolymerizable monomer residues. 100 parts by weight of an N-alkylmaleimide polymer, and at least one dispersion selected from the group consisting of nonionic compounds having no hydrogen bonded to oxygen or nitrogen, polyacrylates, and polyalkylene glycols 2 parts by weight or less of the agent. The resin composition according to one aspect of the present invention is preferably produced by the method for producing an N-alkylmaleimide polymer according to one aspect of the present invention, which includes washing the N-alkylmaleimide polymer. can be done.

ここで、Ｒは炭素数１～１２の直鎖状アルキル基、炭素数３～１２の分岐状アルキル基または炭素数３～６の環状アルキル基を示す。

Here, R represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.

The resin composition according to one aspect of the present invention is preferably produced by the method for producing an N-alkylmaleimide polymer according to one aspect of the present invention, which includes washing the N-alkylmaleimide polymer. can be done. In other words, the N-alkylmaleimide residue represented by general formula (1A) is a residue derived from the N-alkylmaleimide represented by general formula (1). Therefore, the technical features of the N-alkylmaleimide residue represented by the general formula (1A) can be referred to the description of the N-alkylmaleimide represented by the general formula (1), so detailed description thereof is omitted. . Similarly, in the resin composition according to one aspect of the present invention, other copolymerizable monomers, and a nonionic compound having no hydrogen bonded to oxygen or nitrogen, polyacrylate, and polyalkylene glycol At least one or more dispersants selected from the group consisting of the above-mentioned other copolymerizable monomers, as well as nonionic compounds having no hydrogen bonded to oxygen or nitrogen, polyacrylates, and It is the same as at least one dispersant selected from the group consisting of polyalkylene glycols. Therefore, each of these technical features can also be referred to the description of the method for producing an N-alkylmaleimide polymer according to one aspect of the present invention, so the description thereof will be omitted.

Content of at least one dispersant selected from the group consisting of nonionic compounds having no hydrogen bonded to oxygen or nitrogen, polyacrylates, and polyalkylene glycols in the resin composition according to one aspect of the present invention is 2 parts by weight or less per 100 parts by weight of the N-alkylmaleimide polymer. Among them, the amount is preferably 0.01 to 2 parts by weight, particularly preferably 0.01 to 1.5 parts by weight, since a resin composition having particularly excellent optical properties and mechanical strength can be obtained.

<Application>
Various optical members, It can be used for optical lenses, optical sheets, optical films, and the like.

EXAMPLES The present invention will be described below based on examples, but the present invention is not limited to these examples. Commercially available reagents were used unless otherwise specified. As polyvinylpyrrolidone (PVP) K30 and K90, special grades from Fuji Film Wako Pure Chemical Industries, Ltd. were used. As polyvinylpyrrolidone (PVP) K120, PVP K-120 from Ashland Japan Co., Ltd. was used. Metolose (registered trademark) 90SH-100 from Shin-Etsu Chemical Co., Ltd. was used as hydroxypropyl methylcellulose (HPMC). First grade polyethylene glycol (PEG) from Fuji Film Wako Pure Chemical Industries, Ltd. was used. As sodium polyacrylate (NaPAA), Aronbis (registered trademark) MX manufactured by Toagosei Co., Ltd. was used. Perbutyl O manufactured by NOF Corporation was used as tert-butyl peroxy-2-ethylhexanoate. Perbutyl PV from NOF Corporation was used as tert-butyl peroxypivalate. Special grade of FUJIFILM Wako Pure Chemical Industries, Ltd. was used as 1-dodecanethiol.

Evaluation methods and measurement methods for the N-alkylmaleimide polymers obtained in the examples are shown below.

<Average particle size>
150 mg of the N-alkylmaleimide polymer was dispersed in 20 g of ion-exchanged water, and measured using a particle size distribution analyzer MT-3300 (manufactured by Nikkiso Co., Ltd.). The shape was set to a true sphere, and the refractive index was set to 1.549.

<Particle morphology>
Using a tabletop microscope TM3030Plus manufactured by Hitachi High-Tech Co., Ltd., the image signal was set to secondary electrons, and observations were made in standard mode at a magnification of 30 to 100 times.

<N-alkylmaleimide content in polymer>
A predetermined amount of N-alkylmaleimide polymer was dissolved in deuterated chloroform (approximately 5% by weight), and ¹ H - NMR measurements were taken. For copolymers of N-alkylmaleimide and styrene, the N-alkylmaleimide content was calculated from the integral ratio of the peak between 5.0 and 0.3 ppm to the peak between 8.0 and 5.5 ppm.

<Molecular weight of polymer>
The molecular weight distribution was measured using Tosoh GPC (HLC-8320GPC). Two TSKgel Super HM-H columns manufactured by Tosoh were used, the column temperature was set to 40° C., and tetrahydrofuran was used as an eluent. A molecular weight calibration curve was prepared using Tosoh standard polystyrene having a known molecular weight.

<Dispersant Content in Resin Composition>
A predetermined amount of the resin composition is dissolved in deuterated chloroform (about 5% by weight), and ¹ H-NMR measurement of the resulting solution is performed using a JEOL Ltd. 400 MHz NMR (JNM-ECZ400S/L1). gone. Regarding the resin composition of the copolymer of N-alkylmaleimide and styrene and PEG, the peaks of the N-alkylmaleimide polymer between 8.0 and 5.5 ppm and between 5.0 and 0.3 ppm The dispersant content was calculated from the ratio of the sum of the integrals and the integral of the dispersant peak at 3.6 ppm.

<Film formation (1)>
An N-alkylmaleimide polymer was dissolved in 10 times the amount of methylene chloride and spread on a release PET film using an applicator. The PET film on which the polymer solution was spread was covered with a lid to slowly evaporate the solvent. The polymer film formed on the release PET film was peeled off, and dried under reduced pressure for 24 hours in a vacuum dryer set at 105°C.

<Film formation (2)>
A polymer solution having a predetermined concentration was prepared by adding an N-alkylmaleimide polymer to chloroform and stirring with a magnetic stirrer or mixer. The resulting polymer solution was filtered through a 30 μm PP filter and spread on a PET film using a coater. Using three ovens with different temperature settings, the temperature was raised stepwise in the range of 60°C to 155°C and dried. Then, it was dried again at a predetermined temperature using an oven to obtain a film having a film thickness of about 50 μm with no residual solvent [<0.2 wt % (gas chromatography analysis)].

<Glass transition point (Tg)>
Using a differential scanning calorimeter DSC-60 manufactured by Shimadzu Corporation, the glass at the time of second scan heating (heating rate = 10 ° C./min) of the film formed film obtained in <Film forming (1)> The transition point (Tg) was measured.

<Tensile strength>
The tensile strength was measured using a Tensilon universal material testing machine (TENSILON RTG-1210) manufactured by A&D. The formed film obtained in <Film forming (2)> was cut into strips having a width of 10 mm and a length of 90 mm to obtain test pieces. A tensile test was performed under the conditions of a distance between chucks of 50 mm and a tensile speed of 30 mm/min to measure tensile elongation at break and tensile stress at break.

<Haze>
In order to evaluate the transparency of the N-alkylmaleimide polymer, the haze of the formed film obtained in <Film formation (2)> was measured using a spectroscopic haze meter (SH7000 by Nippon Denshoku Industries Co., Ltd.). measured by

<Photoelastic constant>
Measurement was performed using an automatic birefringence controller ABR-EX manufactured by Uniopt. A stress of 0 to 2 N was applied to the film having a width of 4 to 5 mm and a thickness of 35 to 55 μm formed in <Film Forming (1)> at intervals of about 0.1 N to measure the retardation. A photoelastic constant C was calculated from the phase difference and the width of the measured portion in the range of 0.3 to 2N.

<Intrinsic birefringence>
The film formed in <Film Formation (1)> is stretched at a temperature of Tg or higher at a stretching rate of 40 to 100 mm / min and a stretching ratio of 2 to 3 using a film biaxial stretching device IMC-11A9 manufactured by Imoto Seisakusho. Uniaxially stretched at 100%. Then, it was allowed to stand still for 24 hours or more to relax the internal stress, and the absorbance in the infrared region was measured using a Fourier transform infrared spectrophotometer IRTracer-100 manufactured by Shimadzu Corporation. The degree of orientation f of each stretched film was evaluated using the infrared dichroism method from the measured absorbance. Each film thickness d was measured with a micrometer. Further, the retardation Re of each stretched film was measured using an automatic birefringence controller ABR-10A manufactured by Uniopt. The intrinsic birefringence Δn ⁰ was calculated using the following formula (3) from the orientation degree f, the film thickness d, and the measured values of the retardation Re.
Re=Δn ⁰ ·f·d (3)
<Temperature constant of intrinsic birefringence>
<Intrinsic birefringence> The stretched film was heated from 15°C to 70°C in increments of 5°C, and the phase difference at each temperature was measured using an automatic birefringence controller ABR-10A manufactured by Uniopt. , the temperature constant dΔn ⁰ /dT of the intrinsic birefringence was calculated.

Example 1
In a 500 mL four-necked flask equipped with a stirrer, nitrogen inlet and thermometer, 0.852 g of PVP K30, 346.4 g of distilled water, 103.9 g of N-ethylmaleimide, 25.8 g of styrene, and toluene were added. 18.4 g and 0.100 g of tert-butylperoxy-2-ethylhexanoate were added, and after nitrogen bubbling was performed for 1 hour, suspension polymerization was carried out by holding at 70° C. for 2 hours while stirring at 600 rpm. gone. After suspension polymerization was completed, the contents were introduced into 2,500 g of distilled water stirred with a magnetic stirrer and filtered to recover the produced N-alkylmaleimide polymer particles. The recovered polymer particles were washed with 2,000 g of distilled water six times, and then washed with 1,582 g of methanol five times. After that, it was washed once with a mixed solvent of 487 g of toluene and 1,137 g of methanol, and then washed with 1,582 g of methanol five times. Furthermore, after washing once with a mixed solvent of 827 g of toluene and 827 g of methanol, washing was performed 5 times with 1,582 g of methanol. The washed polymer particles were placed in a dryer set at 95° C. and dried under vacuum. Drying was stopped when the weight no longer decreased due to drying, and 74.5 g of an N-ethylmaleimide/styrene copolymer was obtained. Observation of the particle morphology of the polymer particles with a tabletop microscope revealed that the particles had a particle size of about 50 μm to about 2,000 μm. Tables 1 and 2 show the polymerization feed composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the copolymer, and the dispersant content of the resin composition. Table 3 shows the solubility in chloroform and the haze of the formed film.

Comparative example 1
N-ethylmaleimide was prepared in the same manner as in Example 1, except that 0.852 g of hydroxypropylmethylcellulose (HPMC), a nonionic compound having hydrogen bound to oxygen, was used as a dispersant instead of PVP K30. / Styrene copolymer was produced. As a result, 67.5 g of N-alkylmaleimide polymer was obtained. Tables 1 and 2 show the polymerization composition, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in the N-alkylmaleimide polymer, Mw and Mw/Mn. . Table 3 shows the solubility in chloroform, the mechanical strength of the formed film, and the haze.

A gel insoluble in chloroform was generated by using HPMC, which is a nonionic compound having hydrogen bound to oxygen, as a dispersant. In addition, when formed into a film, the haze value of the film is increased, and furthermore, the ratio of units derived from N-alkylmaleimide is substantially the same as that of the N-alkylmaleimide-based copolymer produced in Example 2 described later. Decreased mechanical strength.

Example 2
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 1, except that the polymerization time was changed from 2 hours to 2.25 hours. As a result, 77.3 g of N-alkylmaleimide polymer was obtained. Observation of the particle morphology of the N-alkylmaleimide polymer particles with a desk microscope revealed that the particles had a particle size of about 50 μm to about 2,000 μm. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform, the heat resistance of the formed film, the mechanical strength and the optical properties.

As shown in Tables 1 and 2, increasing the polymerization time increased the N-ethylmaleimide unit content. In addition, it exhibited the same mechanical strength, transparency, photoelastic constant and temperature constant of intrinsic birefringence as the N-alkylmaleimide polymer obtained by bulk polymerization shown in Comparative Example 2 described later.

Comparative example 2
A test tube was charged with 3.8 g of N-ethylmaleimide and 1.2 g of styrene and blended. After sealing the test tube, the contents were mixed by shaking well. The test tube was allowed to stand in a hot water bath at 70° C. for 24 hours to carry out bulk polymerization. The resulting N-alkylmaleimide polymer is a cylindrical mass adhered to the inside of the test tube. In order to remove unreacted monomers, the cylindrical mass is removed from the test tube and once cut into pieces of about 1 cm square. The mixture was crushed into 100 pieces and put into methylene chloride to prepare a transparent N-alkylmaleimide polymer solution. Thereafter, the resulting N-alkylmaleimide polymer solution was added dropwise to methanol to precipitate the N-alkylmaleimide polymer. After filtering with filter paper and removing the filtrate in which the unreacted monomer was dissolved, the N-alkylmaleimide polymer remaining on the filter paper was collected and dried under reduced pressure in a desiccator for 3 hours. After that, it was further dried in a vacuum dryer at 105° C. for 24 hours under reduced pressure to obtain 4.0 g of an N-alkylmaleimide polymer. The particle morphology of the N-alkylmaleimide polymer particles was visually irregular. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform, the heat resistance of the formed film, the mechanical strength and the optical properties.

By producing an N-alkylmaleimide polymer by bulk polymerization, it has the same mechanical strength and transparency as the polymer obtained in Example 2, and has low birefringence (only the absolute value of the photoelastic constant is , and the absolute value of intrinsic birefringence is low), and a polymer that can maintain its low birefringence over a wide range of environmental temperatures was obtained. However, in the production method of Comparative Example 2, unlike the production method of Example 2, in order to remove unreacted monomers, the produced N-alkylmaleimide polymer was removed from the test tube and pulverized. An operation of dissolving in a solvent and an operation of precipitating the N-alkylmaleimide polymer from the obtained solution were further required.

Comparative example 3
6.1 g of N-ethylmaleimide, 2.7 g of styrene, 35.4 g of toluene, and 0.019 g of tert-butyl peroxypivalate are placed in a 75 mL ampoule tube, and after degassing the inside of the ampoule tube, the ampoule is heated with a burner. The tube was melt sealed. The sealed ampoule tube was placed in a hot water bath (set at 50° C.) attached to a shaker and shaken for 10 hours to carry out solution polymerization. The resulting product was added to 400 mL of chloroform to prepare a transparent N-alkylmaleimide polymer solution. Thereafter, the resulting N-alkylmaleimide polymer solution was added dropwise to methanol to precipitate the N-alkylmaleimide polymer. Filtration is carried out with filter paper, the N-alkylmaleimide polymer remaining on the filter paper is collected, and dried under reduced pressure for 10 hours in a vacuum dryer set at 95° C. to obtain 7.9 g of the N-alkylmaleimide polymer. Obtained. The particle morphology of the N-alkylmaleimide polymer particles was visually irregular. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform, the heat resistance of the formed film, and the optical properties.

Compared to the polymer produced in Example 2, the Mw decreased by producing the N-alkylmaleimide polymer by solution polymerization. As a result, the formed film became brittle and could not be evaluated for mechanical strength.

Example 3
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 1, except that the polymerization time was changed from 2 hours to 5 hours. As a result, 84.1 g of N-alkylmaleimide polymer was obtained. Observation of the particle morphology of the N-alkylmaleimide polymer particles with a desk microscope revealed that the particles had a particle size of about 50 μm to about 2,000 μm. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform.

As shown in Tables 1 and 2, increasing the polymerization time increased the N-ethylmaleimide unit content.

Example 4
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 2, except that the amount of PVP K30 added was changed to 17.04 g. As a result, 69.8 g of N-alkylmaleimide polymer was obtained. The average particle diameter of the N-alkylmaleimide polymer particles was 490 μm, and the formation of milli-order particles could be suppressed by increasing the amount of PVP K30 added. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform and the haze of the formed film.

Example 5
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 2, except that 0.852 g of PVP K30 was changed to 3.04 g of PVP K90. As a result, 75.0 g of N-alkylmaleimide polymer was obtained. The average particle size of the N-alkylmaleimide polymer particles was 359 μm, and the change from PVP K30 to PVP K90 could suppress the formation of millimeter-order particles. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform.

Example 6
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 5, except that the polymerization time was changed from 2.25 hours to 5 hours. As a result, 83.4 g of N-alkylmaleimide polymer was obtained. Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform.

As shown in Tables 1 and 2, increasing the polymerization time increased the N-ethylmaleimide unit content.

Example 7
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 6, except that the charged amount of N-ethylmaleimide was changed to 98.1 g and the charged amount of styrene was changed to 31.8 g. . Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform and the haze of the formed film.

As shown in Tables 1 and 2, the N-ethylmaleimide unit content in the N-alkylmaleimide-based polymer could be controlled by reducing the N-ethylmaleimide ratio in the polymerization charge.

Example 8
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 6, except that the charged amount of N-ethylmaleimide was changed to 70.5 g and the charged amount of styrene was changed to 58.7 g. . Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform and the heat resistance of the formed film.

As shown in Tables 1 to 3, by reducing the N-ethylmaleimide ratio in the polymerization charge, the N-ethylmaleimide unit content in the N-alkylmaleimide polymer can be controlled, and the N-ethylmaleimide unit content is 68% by weight. % of the N-alkylmaleimide polymer produced in Example 2, the Tg was lowered, and the heat resistance of the film could be controlled.

Example 9
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 5, except that the amount of PVP K90 added was changed to 0.856 g. As a result, 73.4 g of N-alkylmaleimide polymer was obtained. The average particle size of the N-alkylmaleimide polymer particles was 335 μm, and the average particle size was almost maintained even when the amount of PVP K90 added was reduced. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform and the haze of the formed film.

Example 10
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 5, except that the amount of PVP K90 added was changed to 0.416 g. As a result, 75.8 g of N-alkylmaleimide polymer was obtained. The average particle size of the N-alkylmaleimide polymer particles was 429 μm, and the average particle size tended to increase as the amount of PVP K90 added was reduced to 0.416 g. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform and the haze of the formed film.

As shown in Table 3, the haze of the formed film tended to decrease as the amount of PVP K90 added decreased.

Example 11
An N-cyclohexylmaleimide/styrene copolymer was prepared in the same manner as in Example 8, except that 81.7 g of N-cyclohexylmaleimide was used instead of N-ethylmaleimide and the amount of styrene charged was changed to 47.5g. manufactured. Composition of charge for polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-cyclohexylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform and the heat resistance of the formed film.

Example 12
N-tert-butylmaleimide/styrene was prepared in the same manner as in Example 8, except that 77.1 g of N-tert-butylmaleimide was used instead of N-ethylmaleimide and the amount of styrene charged was changed to 52.4g. Copolymer production was carried out. Polymerization composition, yield, average particle size of N-alkylmaleimide polymer particles, N-tert-butylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and resin composition Dispersant content is shown in Tables 1 and 2. Table 3 shows the solubility in chloroform and the heat resistance of the formed film.

Example 13
The same method as in Example 1 except that the polymerization time was changed from 2 hours to 3 hours, PVP K30 was changed to PVP K120, and 0.100 g of tert-butylperoxy-2-ethylhexanoate was changed to 0.164 g. to produce an N-ethylmaleimide/styrene copolymer. As a result, 79.9 g of N-alkylmaleimide polymer was obtained. The average particle size of the N-alkylmaleimide polymer particles was 297 μm, and by changing from PVP K30 to PVP K120, generation of milli-order particles could be suppressed. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform and the haze of the formed film.

Example 14
The amount of N-ethylmaleimide charged was changed to 104.5 g, the amount of styrene charged to 29.0 g, the amount of toluene charged to 14.9 g, and the amount of PVP K120 added to 0.276 g. An N-ethylmaleimide/styrene copolymer was prepared in the same manner as in Example 13. As a result, 83.5 g of N-alkylmaleimide polymer was obtained. Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform and the haze of the formed film.

Example 15
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 13, except that 0.855 g of PVP K120 was changed to 0.216 g of sodium polyacrylate. As a result, 83.1 g of N-alkylmaleimide polymer was obtained. Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform and the haze of the formed film.

Example 16
In the same manner as in Example 14, N - Preparation of ethylmaleimide/styrene copolymer was carried out. As a result, 87.5 g of N-alkylmaleimide polymer was obtained. Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform, the heat resistance of the formed film, and the optical properties.

Example 17
An N-ethylmaleimide/styrene copolymer was produced in the same manner as in Example 16, except that the amount of polyethylene glycol added was changed to 0.031 g. As a result, 91.2 g of an N-alkylmaleimide polymer was obtained. Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform, the heat resistance of the formed film, and the optical properties.

Example 18
In a 500 mL four-necked flask equipped with a stirrer, nitrogen inlet and thermometer, 0.860 g of PVP K30, 347.1 g of distilled water, 99.2 g of N-ethylmaleimide, 22.6 g of styrene, methacrylic acid 26.9 g of methyl and 0.185 g of tert-butylperoxy-2-ethylhexanoate were added, and after bubbling with nitrogen for 1 hour, the suspension was maintained at 70°C for 2 hours while stirring at 600 rpm. Polymerization was carried out. After suspension polymerization was completed, the contents were introduced into 2,500 g of distilled water stirred with a magnetic stirrer and filtered to recover the produced N-alkylmaleimide polymer particles. The recovered polymer particles were washed with 2,000 g of distilled water six times, and then washed with 1,582 g of methanol five times. The washed polymer particles were placed in a dryer set at 90° C. and dried under vacuum. Drying was stopped when the weight no longer decreased due to drying, and 96.1 g of N-ethylmaleimide/styrene/methyl methacrylate copolymer was obtained. Table 1 shows the polymerization composition, yield, average particle size of the N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in the copolymer, Mw and Mw/Mn, and the dispersant content of the resin composition. and Table 2. Table 3 shows the solubility in chloroform and the haze of the formed film.

Example 19
Charge amount of N-ethylmaleimide to 96.4 g, charge amount of styrene to 24.1 g, methyl methacrylate to 28.3 g, PVP K30 to 0.860 g to polyethylene glycol 0.029 g, polymerization time to 7 hours , and 0.148 g of 1-dodecanethiol was added as a chain transfer agent to produce an N-ethylmaleimide/styrene/methyl methacrylate copolymer in the same manner as in Example 18. As a result, 108.4 g of N-alkylmaleimide polymer was obtained. Preparation composition of polymerization, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in N-alkylmaleimide polymer, Mw and Mw/Mn, and dispersant for resin composition Contents are shown in Tables 1 and 2. Table 3 shows the solubility in chloroform and the haze of the formed film.

Comparative example 4
N-Ethylmaleimide/styrene/N-ethylmaleimide/styrene/ A methyl methacrylate copolymer was produced. As a result, 85.3 g of N-alkylmaleimide polymer was obtained. Tables 1 and 2 show the polymerization composition, yield, average particle size of N-alkylmaleimide polymer particles, N-ethylmaleimide unit content in the N-alkylmaleimide polymer, Mw and Mw/Mn. . Table 3 shows the solubility in chloroform.

A gel insoluble in chloroform was generated by using HPMC, which is a nonionic compound having hydrogen bound to oxygen, as a dispersant.

Comparative example 5
A test tube was charged with 3.15 g of N-ethylmaleimide, 0.85 g of styrene, and 1.00 g of methyl methacrylate and blended. After sealing the test tube, the contents were mixed by shaking well. The test tube was allowed to stand in a hot water bath at 70° C. for 24 hours to carry out bulk polymerization. The resulting N-alkylmaleimide polymer is a cylindrical mass adhered to the inside of the test tube. In order to remove unreacted monomers, the cylindrical mass is removed from the test tube and once cut into pieces of about 1 cm square. The mixture was crushed into 100 pieces and put into methylene chloride to prepare a transparent N-alkylmaleimide polymer solution. Thereafter, the resulting N-alkylmaleimide polymer solution was added dropwise to methanol to precipitate the N-alkylmaleimide polymer. After filtering with filter paper and removing the filtrate in which the unreacted monomer was dissolved, the N-alkylmaleimide polymer remaining on the filter paper was collected and dried under reduced pressure in a desiccator for 3 hours. After that, it was further dried in a vacuum dryer at 105° C. for 24 hours under reduced pressure to obtain 3.9 g of an N-alkylmaleimide polymer.

The particle morphology of the N-alkylmaleimide polymer particles was visually irregular. Tables 1 and 2 show the polymerization charge composition, yield, N-ethylmaleimide unit content, Mw and Mw/Mn in the N-alkylmaleimide polymer, and dispersant content of the resin composition. Table 3 shows the solubility in chloroform, the heat resistance of the formed film, the mechanical strength and the optical properties.

By producing an N-alkylmaleimide polymer by bulk polymerization, a polymer having transparency equivalent to that of the polymer obtained in Example 18 was obtained. However, in the production method of Comparative Example 5, unlike the production method of Example 18, in order to remove unreacted monomers, the produced N-alkylmaleimide polymer was removed from the test tube and pulverized. An operation of dissolving in a solvent and an operation of precipitating the N-alkylmaleimide polymer from the obtained solution were further required.

Comparative example 6
3.36 parts by weight of PVP K30 was added to 100 parts by weight of the N-alkylmaleimide polymer synthesized in Comparative Example 2 to obtain a resin composition. Using the obtained resin composition, a film was obtained in <Film Formation (2)>.

Table 2 shows the dispersant content of the resin composition. Table 3 shows the solubility in chloroform and the haze of the formed film.

An increase in the dispersant content in the resin composition increased the haze of the formed film.

Claims (7)

A monomer mixture containing 20 to 100% by weight of N-alkylmaleimide represented by the following general formula (1) and 0 to 80% by weight of other copolymerizable monomers having hydrogen bonded to oxygen or nitrogen is added. Suspension polymerization in an aqueous medium using an oil-soluble radical polymerization initiator in the presence of at least one dispersant selected from the group consisting of nonionic compounds, polyacrylates, and polyalkylene glycols. A method for producing an N-alkylmaleimide polymer characterized by:

(Here, R represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.) Claim 1, wherein R is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, hexyl, cyclohexyl or octyl. A method for producing an N-alkylmaleimide polymer. 3. The N- according to claim 1 or 2, wherein the other copolymerizable monomer is a vinyl aromatic hydrocarbon, an olefin, an acrylic acid alkyl ester, a methacrylic acid alkyl ester or a carboxylic acid vinyl ester. A method for producing an alkylmaleimide polymer. 3. The method for producing an N-alkylmaleimide polymer according to claim 1, wherein the dispersant is at least one selected from the group consisting of polyvinylpyrrolidone, sodium polyacrylate and polyethylene glycol. 3. The method for producing an N-alkylmaleimide polymer according to claim 1, wherein the N-alkylmaleimide polymer has a weight average molecular weight of 200,000 to 2,000,000. After filtering the N-alkylmaleimide polymer obtained by suspension polymerization,
Washing the N-alkylmaleimide polymer with a solvent that dissolves the dispersant without dissolving the N-alkylmaleimide polymer, and removing unreacted monomers without dissolving the N-alkylmaleimide polymer. 3. The method for producing an N-alkylmaleimide-based polymer according to claim 1, further comprising washing the N-alkylmaleimide-based polymer with a solvent that dissolves the body. 100 parts by weight of an N-alkylmaleimide polymer comprising 20 to 100% by weight of N-alkylmaleimide residues represented by the following general formula (1A) and 0 to 80% by weight of other copolymerizable monomer residues; and a resin composition containing 2 parts by weight or less of at least one dispersant selected from the group consisting of nonionic compounds having no hydrogen bound to oxygen or nitrogen, polyacrylates, and polyalkylene glycols.

(Here, R represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms or a cyclic alkyl group having 3 to 6 carbon atoms.)