JP2002030119A - Maleimide copolymer and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new maleimide copolymer excellent in heat resistance and heat stability and further excellent in alkali solubility, which copolymer has a specified amount of N-substituted maleimide groups, aromatic vinyl monomer groups, and unsaturated monocarboxylic acid monomer groups. SOLUTION: There is provided a maleimide copolymer containing (1) a maleimide copolymer prepared by polymerizing a monomer component containing an N-substituted maleimide monomer, an aromatic vinyl monomer, and an unsaturated monocarboxylic acid monomer, having a content of insolubles in an aqueous alkali solution of at most 10%, and containing at most 10% compound (2) of a specified structure represented by formula I (wherein R1s, which are independent of each other, are each an alkyl, a cycloalkyl, an aryl, an alkyl-substituted aryl, or a halogen-substituted aryl; R2 is hydrogen or methyl; and R3 to R6 are each independently hydrogen, an alkyl, a cycloalkyl, or a cycloalkyl-, aryl- alkylaryl-, or halogen-substituted aryl).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel maleimide-based copolymer. More specifically, the maleimide-based copolymer has a specific amount of N-substituted maleimide-based monomer group, aromatic vinyl-based monomer group and unsaturated monocarboxylic acid monomer group, and has heat resistance and flow heat stability. And a novel maleimide-based copolymer excellent in solubility in an aqueous alkali solution.

[0002]

2. Description of the Related Art Copolymers obtained by copolymerizing an N-substituted maleimide monomer and an aromatic vinyl monomer have high heat resistance and thermal stability. Or a resin material having heat resistance and transparency as a film or molded product itself.

For example, a copolymer obtained by copolymerizing an N-substituted maleimide monomer and an aromatic vinyl monomer has excellent compatibility with an AS resin. Compositions blended with ABS resin (JP-A-63-1
59458) has been proposed. Further, a heat-resistant resin excellent in transparency and made of a copolymer comprising an alkylmaleimide-based monomer and an aromatic vinyl-based monomer (JP-A-2-127407)
Has been proposed. On the other hand, alkali-soluble polymers are dissolved and removed with a basic liquid, so they can be used for various purposes such as packaging, surface protection, and adhesive layers. Can be removed. Heretofore, there has been proposed a film material which is a polymer obtained by copolymerizing a (meth) acrylic acid ester and an unsaturated carboxylic acid and which can be dissolved in a basic liquid (JP-A-7-149837). In addition, when a maleimide-based copolymer is produced by radical polymerization of a maleimide-based monomer and an aromatic vinyl-based monomer, via a Diels-Alder reaction between the maleimide-based monomer and the aromatic vinyl-based monomer As a result, it is known that compound (1) is produced as a by-product, and a method for minimizing the amount has been proposed. (JP-A-6-93044) However, even with the method for producing these copolymers, a maleimide-based copolymer having excellent heat resistance and flow heat stability and excellent solubility in an aqueous alkali solution can be obtained. I couldn't do that. Generally, the maleimide-based monomer and the aromatic vinyl-based monomer have a high alternating polymerizability, and when the polymerization is performed under ordinary radical polymerization, an alternating copolymer tends to be formed first. Similarly, when an unsaturated monocarboxylic acid-based monomer is introduced as the third component, a copolymer containing a large amount of a maleimide-based monomer and an aromatic vinyl-based monomer is generated in the early stage of polymerization,
As a result, the unsaturated monocarboxylic acid monomer tends to remain, and a copolymer containing a large amount of the unsaturated monocarboxylic acid monomer tends to be formed in the latter half of the polymerization. As a result, the obtained copolymer has a large composition distribution,
Contains components with poor thermal stability and poor solubility in alkaline aqueous solutions,
The performance of the polymer as a whole is inferior. Therefore, simply copolymerizing a maleimide-based monomer with an aromatic vinyl-based monomer and an unsaturated monocarboxylic acid-based monomer is excellent in heat resistance and flow heat stability, and furthermore, in solubility in an aqueous alkali solution. However, no excellent maleimide copolymer composition could be obtained.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a maleimide-based polymer which has excellent heat resistance and thermal stability, and also has excellent solubility in an aqueous alkali solution. As an issue.

[0005]

In order to solve the above-mentioned conventional problems, the present inventor has proposed a copolymer of a maleimide monomer, an aromatic vinyl monomer and an unsaturated carboxylic acid monomer. As a result of intensive studies on the manufacturing method of the product. as a result,
10 to 80% by weight of an N-substituted maleimide monomer (a), 10 to 80% by weight of an aromatic vinyl monomer (b) and 1 to 70% by weight of an unsaturated monocarboxylic acid monomer (c) Maleimide copolymer obtained by polymerizing monomer components containing
In the method for producing the above, after the monomer (b) and the monomer (c) and, if necessary, the solvent are supplied to the reactor, the polymerization is started and the remaining monomer (b) and the monomer ( By carrying out the polymerization reaction while continuously or intermittently feeding the monomer (a) into the polymerization system without previously mixing the monomer (a) and the monomer (a), the composition distribution of the polymer is reduced, and as a result It has been found that the generation of insoluble components can be suppressed as much as possible. By adopting the above method, it was found that a maleimide-based copolymer composition having excellent heat resistance and thermal stability, and also having excellent solubility in an aqueous alkali solution, could be obtained, and the present invention was completed. It led to. That is, in order to solve the above-mentioned problems, the maleimide-based copolymer according to claim 1 has an N-substituted maleimide-based monomer (a) of 10 to 80% by weight and an aromatic vinyl-based monomer (b) of 10 to 10% by weight. A maleimide-based copolymer obtained by polymerizing a monomer component containing 80% by weight and 1 to 70% by weight of an unsaturated monocarboxylic acid-based monomer (c), wherein an insoluble content of an alkaline aqueous solution is 10% by weight or less. It is characterized by being. Further, in order to solve the above-mentioned problems, the maleimide-based copolymer composition according to claim 2 has an N-substituted maleimide-based monomer (a) of 10 to 80% by weight and an aromatic vinyl-based monomer (b). A) a maleimide-based copolymer obtained by polymerizing a monomer component containing 10 to 80% by weight and 1 to 70% by weight of an unsaturated monocarboxylic acid monomer (c); The content of the compound (2) having a specific structure represented by
It is characterized by being a maleimide-based copolymer having a content of 0% by weight or less.

[0006]

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(Wherein, in the general formula (1), R ¹ independently represents an alkyl group, a cycloalkyl group, an aryl group, an alkyl-substituted aryl group or a halogen-substituted aryl group; R ² represents hydrogen or a methyl group. Represents; R ³ to
R ⁶ each independently represents hydrogen, an alkyl group, a cycloalkyl group, a cycloalkyl group, an aryl group, an alkyl-substituted aryl group, or a halogen-substituted aryl group. ).

Further, in order to solve the above-mentioned problems, the method for producing a maleimide-based copolymer according to the third aspect of the present invention provides an N-substituted maleimide-based monomer (a) in an amount of 10 to 80% by weight and an aromatic vinyl-based monomer. A maleimide copolymer (1) produced by polymerizing a monomer component containing 10 to 80% by weight of the monomer (b) and 1 to 70% by weight of the unsaturated monocarboxylic acid monomer (c) is produced. In the method, after supplying the monomers (b) and (c) and, if necessary, a solvent to the reactor, the polymerization is started and the remaining monomers (b) and (c) The polymerization reaction is carried out while continuously or intermittently supplying the monomer (a) into the polymerization system.

In order to solve the above-mentioned problems, a method for producing a maleimide-based copolymer according to claim 4 is to provide an N-substituted maleimide-based monomer (a) in an amount of 10 to 80% by weight and an aromatic vinyl-based monomer. A maleimide copolymer (1) produced by polymerizing a monomer component containing 10 to 80% by weight of the monomer (b) and 1 to 70% by weight of the unsaturated monocarboxylic acid monomer (c) is produced. In the method, after supplying the monomers (b) and (c) and, if necessary, a solvent to the reactor, the polymerization is started and the remaining monomers (b) and (c) When conducting the polymerization reaction while continuously or intermittently supplying the monomer (a) into the polymerization system, the monomers (a) and (b) are supplied without being mixed in advance. It is characterized by.

Hereinafter, the present invention will be described in detail. Monomer containing an N-substituted maleimide monomer (a), an aromatic vinyl monomer (b), and an unsaturated monocarboxylic acid monomer (c) constituting the maleimide copolymer (1) As the composition ratio of the body components, etc., the monomer components including the N-substituted maleimide monomer (a), the aromatic vinyl monomer (b), and the unsaturated carboxylic acid monomer (c) And, if necessary, other copolymerizable monomer (d), when the total amount of the monomer components is 100% by weight, the constitutional ratio of each monomer component is represented by ( a) 10 to 80% by weight, (b) 10
It is preferable that the content is from about 80% by weight and from 1 to 70% by weight of (c), and from 0 to 20% by weight of another copolymerizable monomer (d). More preferably, (a) 20 to 60% by weight,
(B) 20 to 60% by weight, (c) 5 to 60% by weight,
(D) 0 to 15% by weight. More preferably,
(A) 30 to 50% by weight, (b) 30 to 50% by weight,
(C) 10 to 50% by weight, and (d) 0 to 10% by weight.

When the content of the unsaturated monocarboxylic acid monomer (c) is less than the above range, the solubility of the aqueous alkali solution may be reduced. If it exceeds the above range, heat resistance and thermal stability may be reduced. When the content of the N-substituted maleimide-based monomer (a) is less than the above range, heat resistance may be reduced. When the content exceeds the above range, the content of the maleimide-based copolymer (1) of the present invention may be reduced. In addition to reducing the solubility of the aqueous alkali solution, when used for applications such as packaging, surface protection, and adhesive layers, the mechanical strength may be reduced.

The maleimide copolymer (1) of the present invention
Is preferably not more than 10% by weight, more preferably not more than 5% by weight of an alkali aqueous solution insoluble matter,
Most preferably, it is at most 3% by weight. The insoluble content of the alkali aqueous solution was evaluated based on the solubility of the maleimide copolymer (1) of the present invention in a 0.5% -KOH aqueous solution. More specifically, the alkali insoluble content of a 50 μm thick film made of the maleimide copolymer (1) of the present invention was determined by a solubility test in 200 ml of a 0.5% KOH aqueous solution at 50 ° C. , Can be evaluated.

The compound (2) having a specific structure represented by the following general formula (1) contained in the maleimide copolymer (1) is preferably at most 10% by weight, more preferably at most 5% by weight. It is more preferably at most 1% by weight, most preferably at most 1% by weight. When the amount of the compound (2) represented by the general formula (1) is larger than the above range, the thermal stability and the solubility of the maleimide-based copolymer in an aqueous alkali solution may be reduced.

[0014]

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(However, in the general formula (1), R ¹ independently represents an alkyl group, a cycloalkyl group, an aryl group, an alkyl-substituted aryl group or a halogen-substituted aryl group; R ² represents hydrogen or a methyl group. Represents; R ³ to
R ⁶ each independently represents hydrogen, an alkyl group, a cycloalkyl group, a cycloalkyl group, an aryl group, an alkyl-substituted aryl group, or a halogen-substituted aryl group. Examples of the N-substituted maleimide-based monomer (a) include, specifically, aromatic-substituted maleimides such as phenylmaleimide, benzylmaleimide, naphthylmaleimide, and o-chlorophenylmaleimide, methylmaleimide, ethylmaleimide, propylmaleimide, Examples include alkyl-substituted maleimides such as isopropyl maleimide and cyclohexyl maleimide. These maleimide-based monomers include 1
Species or a mixture of two or more can be used. Of these, phenylmaleimide and cyclohexylmaleimide are preferred because of their industrial availability and relatively low toxicity of monomers. Furthermore, cyclohexylmaleimide is most preferred from the viewpoint of transparency and thermal stability. When using cyclohexylmaleimide, it is preferable to use it after reducing the content of cyclohexylaminosuccinic anhydride contained as a by-product in cyclohexylmaleimide to 1% by weight or less.

As the aromatic vinyl monomer (b), specifically, styrene, α-methylstyrene, p-
Methyl styrene, p-chlorostyrene and the like can be mentioned. These aromatic vinyl monomers can be used alone or in combination of two or more. Of these, styrene is preferred from the viewpoint of industrial availability and polymerizability.

Specific examples of the unsaturated monocarboxylic acid monomer (c) include methacrylic acid and acrylic acid. These unsaturated monocarboxylic acid monomers can be used alone or in combination of two or more.

The other copolymerizable monomer (d) other than the above (a), (b) and (c) is not particularly limited as long as it does not depart from the gist of the present invention. Methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate; acrylates such as methyl acrylate and butyl acrylate; vinyl cyanide such as acrylonitrile and methacrylonitrile; and maleic anhydride And unsaturated dicarboxylic anhydrides such as acids. These and other copolymerizable monomers can be used alone or in combination of two or more. The molecular weight of the maleimide-based copolymer (1) is preferably such that the weight average molecular weight is in the range of 5,000 to 200,000 in order to exhibit alkali-solubility,
More preferably in the range of 5,000 to 100,000, 10,000
~ 50,000 is more preferred. When the weight average molecular weight exceeds the above range, the solubility of the aqueous alkali solution may be reduced. On the other hand, when the ratio is below the above range, heat resistance and thermal stability may decrease.

Further, the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight of the maleimide copolymer (1) of the present invention as measured by GPC is preferably 4.0 or less,
It is more preferably at most 3.0, most preferably at most 2.5. If Mw / Mn exceeds 4.0, thermal stability and alkali aqueous solution solubility may be reduced.

The maleimide-based copolymer (1) contains 50 to 3
It has an acid number of 00 mg KOH / g, preferably 70-200 mg KOH / g. When the acid value of the polymer (1) falls below the above range, the polymer loses the solubility in an aqueous alkali solution, and when the acid value exceeds the above range, the polymer (1) becomes brittle, and when it is made into various molded articles, strength properties are hardly exhibited. Become. For example, in a film, a coating material, and a coating material, the film strength is hardly obtained, and the film is easily broken.

As a method for producing the maleimide-based copolymer (1), known solution polymerization, suspension polymerization, and emulsion polymerization can be adopted. In the suspension polymerization and emulsion polymerization, a suspending agent and an emulsifier are used. Since it is mixed, it may cause a decrease in transparency. In addition, in the suspension polymerization and the emulsion polymerization, the specific impurity (2) may be generated, the composition may be easily distributed, and the solubility of the alkaline aqueous solution may be reduced. Further, in the suspension polymerization method and the emulsion polymerization method, the reaction is carried out in a dispersed state in water. There is a possibility that the body is not sufficiently mixed, and the alkali-solubility and thermal stability are reduced. Therefore, the maleimide-based copolymer (1) of the present invention is preferably a polymer obtained by a solution polymerization method in which a maleimide-based monomer is polymerized in the presence of a solvent using a maleimide-based monomer. is there. Further, the most preferred form is a copolymer obtained by a batch solution polymerization method using a maleimide-based monomer.

The polymerization temperature in the above polymerization reaction may be set according to the polymerization initiator to be used, etc., and is not particularly limited, but is preferably 50 ° C. to 200 ° C., and is preferably 80 ° C. to 150 ° C.
C is more preferred. If the polymerization temperature is lower than the above range, it is necessary to use an initiator having a low decomposition temperature, which is disadvantageous for industrial production such as requiring equipment for cooling and storing the initiator. Exceeding the above range is not preferable because the monomer starts thermal polymerization during the heating to the polymerization temperature.

The solvent used in the solution polymerization is not particularly limited. For example, the solvent does not interfere with the solution polymerization reaction, and both the monomer for producing the polymer of the present invention and the produced polymer of the present invention are used. There is no particular limitation as long as it is a liquid that can dissolve, for example, aliphatic alcohols having 1 to 3 carbon atoms such as methanol, ethanol and glycol, cyclic ethers such as tetrahydrofuran and methyl ethyl ketone,
Examples thereof include ketones such as methyl isobutyl ketone, and polar organic solvents such as dimethyl sulfoxide and dimethylformamide. The solvent used in the non-aqueous dispersion polymerization is not particularly limited as long as the above-mentioned monomer for obtaining the polymer of the present invention can be dissolved therein, and the produced polymer of the present invention is insoluble in liquid. Examples thereof include non-polar organic solvents such as liquid hydrocarbons such as benzene, toluene, hexane, and cyclohexane. The amount of the solvent used in the solution polymerization or the non-aqueous dispersion polymerization is preferably 20 to 80% by weight based on the total weight of the monomers.
~ 70% by weight is more preferred. If it is below the range, stirring may be insufficient due to thickening at the end of polymerization,
If the molecular weight exceeds the above range, the molecular weight of the produced polymer may not be increased within the above range. As the polymerization initiator, a peroxide or an azo compound, which is a known radical polymerization initiator, is suitably used, and is appropriately determined according to the polymerization temperature. It is used in a proportion of 1.0% by weight.

In the polymerization method of the present invention, a chain transfer agent can be used for adjusting the molecular weight. For example, α-methylstyrene or a mercaptan-based chain transfer agent can be used.

In the polymerization method of the maleimide-based copolymer (1) in the present invention, it is preferable to take special measures for the method of supplying the monomers to be used. After supplying the monomer (b) and the monomer (c) and a solvent as necessary to the reactor,
The polymerization is started by adding an initiator, and the remaining monomers (b) and (c) and (a) are continuously or intermittently fed into the polymerization system without prior mixing. It is most preferable to continue the reaction for 0.5 hour or more after the completion of the reaction and supply of all the monomers. The ratio of the amount of the N-substituted maleimide-based monomer (a) supplied to the reaction system before the start of the polymerization and the amount of the N-substituted maleimide monomer (a) supplied continuously or intermittently after the start of the polymerization reaction is 0-5 / A ratio in the range of 100-95% by weight is preferred, a ratio in the range of 0-1 / 100-99% by weight is more preferred, but it is most preferred to supply the whole amount continuously or intermittently.

The ratio of the amount of the aromatic vinyl monomer (b) supplied to the reaction system before the start of the polymerization and the amount supplied continuously or intermittently after the start of the polymerization reaction is 1 -9
A ratio in the range of 9 / 99-1% by weight is preferred, and 5-90 / 9
More preferred is a ratio in the range of 5-10% by weight, 15-75%.
More preferred is a ratio in the range of / 85-25% by weight,
Most preferred is a ratio in the range of 60 / 70-40% by weight.

The ratio of the amount of the unsaturated monocarboxylic acid monomer (c) supplied to the reaction system before the start of the polymerization and the amount supplied continuously or intermittently after the start of the polymerization is 1-99.
A ratio in the range of 9 / 99-1% by weight is preferred.
More preferred is a ratio in the range of 90-10% by weight, 25-25% by weight.
More preferred is a ratio in the range of 5 / 75-25% by weight,
Most preferred is a ratio in the range of -70 / 70-30% by weight.

By adopting this polymerization method, it is possible to suppress the formation of the compound (2) having the specific structure represented by the above general formula (1), and to suppress the decrease in the solubility of the aqueous alkali solution, The amount of maleimide monomer remaining in the resulting maleimide-based copolymer can be effectively reduced. When the total amount of the N-substituted maleimide monomer and the aromatic vinyl monomer is charged from the initial stage of polymerization and the polymerization is started, an alternating copolymer is preferentially formed in the early stage of polymerization, and thereafter, the remaining copolymer is formed. Since a polymer having a large number of structural units of a saturated carboxylic acid-based monomer is produced, a mixture of an alternating copolymer and a maleimide-based copolymer having a large number of structural units derived from an unsaturated carboxylic acid-based monomer is obtained. The resulting maleimide-based copolymer has an undesirably high composition distribution and reduced alkali-solubility. Further, when the N-substituted maleimide-based monomer (a) and the aromatic vinyl-based monomer (b) are previously charged into the polymerization system and the polymerization is started, the above-mentioned general formula (1) The compound (2) having the specific structure shown is easily produced as a by-product.

Further, after the supply of all the N-substituted maleimide monomer (a) is completed, the polymerization reaction is continued for 0.5 hour or more, more preferably for 1 hour or more, so that the remaining N-substituted maleimide monomer can be obtained. The monomer (a) can be reduced.
The N-substituted maleimide-based monomer (a) is used in a polymerization reaction under the condition that 90% by weight or more, preferably 95% by weight or more, more preferably the entire amount of the N-substituted maleimide monomer (a) is continuously or intermittently charged into the polymerization system. Need to do. If the initial amount of the N-substituted maleimide-based monomer (a) is 10
When the polymerization is started under the condition of more than 10% by weight, the production amount of the alternating copolymer of the aromatic vinyl monomer (b) and the N-substituted maleimide monomer (a) increases, and the alkali-solubility increases. This is because there is a risk of reduction.

It is desirable that the N-substituted maleimide monomer (a) and the aromatic vinyl monomer (b) are separately supplied to the polymerization system without being mixed. When mixed and supplied, the compound (2) having the specific structure represented by the general formula (1) is easily produced as a by-product in the mixed solution. As a method of removing the volatile component from the solution after the polymerization reaction and separating the maleimide-based copolymer (1), a method of heating under vacuum, or a method of charging the maleimide-based copolymer (1) by pouring it into a poor solvent Can be employed, and a method of filtering the solution by adding it to a poor solvent is not industrially suitable because the equipment is excessively large. Therefore, it is preferable to volatilize and remove the solvent and the residual monomer by heating under vacuum. Further, it is preferable to provide a facility for volatilizing and removing the solvent and the residual monomer as required. As the above heated solvent recovery equipment, vacuum heating in a devolatilization tank, desolvation in a twin screw extruder, or the like is preferably used. In addition, preconcentration is performed in advance in a devolatilization tank,
Desolvation can be completed by a screw extruder.

The maleimide copolymer (1) which can be used in the present invention is an N-substituted maleimide monomer (a)
The remaining volatile components such as monomer components and solvents other than 2000
ppm or less, preferably 1000 ppm or less, more preferably 500p
pm or less. It is not preferable that the residual volatile matter is large because heat stability is reduced or coloring is caused. Further, the maleimide-based copolymer (1) of the present invention is more preferably
It is preferable that the content of the remaining N-substituted maleimide-based monomer (a) is not more than a specific amount. Specifically, the content of the N-substituted maleimide-based monomer (a) is preferably 500 ppm or less, more preferably 200 ppm or less. More preferably, it is 100 ppm or less.

The maleimide copolymer (1) of the present invention comprises:
Used in combination with one or more resins selected from other thermoplastic resins such as ABS resin, AS resin, polystyrene, acrylic resin, vinyl chloride resin, polyamide, polyester, PPE resin, polyether sulfide resin and PBT resin You may. Further, a thermosetting resin such as an unsaturated polyester alkyd resin, an epoxy resin, a urethane resin, and a bismaleimide / polyfunctional amine curing system may be blended. In addition, glass fiber, carbon black,
Inorganic fillers such as talc, clay, calcium carbonate, and magnesium carbonate, halogen-based and / or phosphorus-based flame retardants, molding aids such as stearates, ultraviolet absorbers, antioxidants, antistatic agents, dyes and / or Alternatively, various additives such as a coloring agent such as a pigment and a foaming agent can be added according to the purpose of use. The amounts of these additives can be appropriately set according to the purpose, and known amounts such as general literatures can be employed. In addition, the maleimide-based copolymer (1) of the present invention is polymerized using a specific monomer component and has specific physical properties. Has ability. Therefore, after using as a cover film, a coating film, a base material protection mask, a protection film, and a coating material, the film, the cover, and the coating material can be easily removed with an alkaline aqueous solution. Further, the use form, application, and applicable field of the film etc. of the present invention are not particularly limited, and the film can be used in an area requiring alkali aqueous solution solubility, heat resistance and thermal stability.

Further, the material of the base material covered by the film or the coating material made of the maleimide copolymer (1) of the present invention is not particularly limited. For example, various metals, copper, iron,
It is not particularly limited, such as plastic materials. The coating method and the coating method are not particularly limited either. For example, the maleimide-based copolymer (1) of the present invention
May be formed into a thin film or the like with a coater or the like and coated.
Moreover, you may shape | mold into a cast film and cover an object. Moreover, you may apply directly to a base material. If necessary, the maleimide copolymer (1) of the present invention is dissolved in a solvent or the like so that it can be applied to various methods of coating, coating, and coating. It can be made into a film.

The carboxyl group of the maleimide-based copolymer (1) of the present invention is reacted with a compound having a functional group capable of reacting with the carboxyl group to give various functions to the maleimide-based copolymer of the present invention. You can also have In this case, the modification amount and the compound to be modified can be selected as long as the solubility of the maleimide copolymer of the present invention in alkaline water is not hindered. Examples of the compound having a functional group that can react with the carboxyl group include an epoxy compound, a compound having a functional group that reacts with the carboxyl group by transesterification, and various amines. For example, if an amine is reacted, an amide ester structure can be introduced into the maleimide copolymer (1) of the present invention, but is not particularly limited.

[0035]

EXAMPLES The present invention will be described below in detail with reference to examples, but the scope of the present invention is not limited by these examples.

In the present invention, the contents of the aromatic vinyl monomer unit and the N-substituted maleimide monomer unit in the maleimide copolymer were determined by elemental analysis and NMR. Further, the remaining volatile components and the amount of the remaining maleimide-based monomer in the maleimide-based copolymer were measured by gas chromatography. Also, weight average molecular weight (Mw) and number average molecular weight
(Mn) was calculated from an elution curve of gel permeation chromatography using tetrahydrofuran as a solvent, using a standard polymer of polystyrene as a standard.

Formula (1) in the maleimide-based copolymer
The content of the compound (2) having a specific structure represented by is determined from the area ratio measured by gel permeation chromatography (GPC). In addition, a compound having a specific structure is fractionated by GPC, and MASS spectrum, IR spectrum,
Its structure was confirmed by ¹ H-NMR and ¹³ C-NMR spectra.

In the above NMR analysis, measurement was carried out in deuterated chloroform (CDCl ₃ ) using tetramethylsilane as a standard substance, and ¹ H-NMR spectrum and ¹³ C-NM
An R spectrum was obtained. The NMR apparatus used was VXR-
300S (manufactured by Varian Inc.). IR analysis is performed by an infrared analyzer (FT / IR-
3, Shimadzu Corporation). Mass spectrometry was performed using an M-2000A mass spectrometer (manufactured by Hitachi, Ltd.).

The solubility of the maleimide-based copolymer of the present invention in an aqueous alkali solution was measured as follows. That is, the copolymer was dissolved in MIBK, applied on a glass plate using a die coater, and dried to form a 50 μm film. After peeling off the glass plate, the film was cut into a 10 cm square, % -KOH aqueous solution
The solubility of the polymer in an aqueous alkali solution was measured by an operation of stirring at 1 ° C. for 1 hour. When an insoluble matter was found, the impurities separated by filtration were dried, the weight was measured, and the weight was compared with the weight of the film before dissolution to determine the content of alkali-insoluble components. When the film was dissolved, the insoluble content was set to 0.

The glass transition point of the maleimide-based copolymer (T
g) was measured by the midpoint method by DSC. That is, using a DSC-8230 manufactured by Rigaku Denki Co., Ltd., under a nitrogen gas flow, using α-alumina as a reference, the temperature rising rate was 5 ° C. /
Calculated from the DSC curve measured in minutes.

<Example 1> A 2 L flask was purged with nitrogen.
8 parts of styrene, 3 parts of methacrylic acid, 53 parts of methyl isobutyl ketone (MIBK), and 1.0 part of α-methylstyrene dimer were charged, and the temperature of the polymerization system was raised to 110 ° C. to obtain MIBK.
Starts refluxing, 0.003 part of t-butylperoxyisopropyl carbonate as an initiator is added to initiate polymerization, and 8 parts of styrene, 2 parts of methacrylic acid, and t-butyl 0.003 parts of peroxyisopropyl carbonate was added dropwise to 13 parts of N-cyclohexylmaleimide (CHMI) as MIBK as MIBK.
In 13 parts, the solution dissolved at 60 ° C. was continuously supplied over 3 hours, and the polymerization was further continued for 2 hours. After diluting the polymerization solution with MIBK, it was poured into hexane to obtain a maleimide-based copolymer (1-1) as a precipitate. Table 1 shows the physical properties of the obtained maleimide-based copolymer (1-1).

<Example 2> The initial charge of styrene was 6.
5 parts, methacrylic acid 5 parts, 6.5 drops of styrene
Parts, methacrylic acid was changed to 6 parts, and CHMI was changed to 10 parts, and the same operation as in Production Example 1 was performed.
After dilution with BK, the mixture was poured into hexane to obtain a maleimide copolymer (1-2) as a precipitate. Table 1 shows the physical properties of the obtained maleimide-based copolymer (1-2).

Example 3 The same operation as in Production Example 2 was carried out except that N-phenylmaleimide was used instead of CHMI. The polymerization solution was diluted with MIBK, and then poured into hexane to obtain a precipitate. Maleimide copolymer (1
-3) was obtained. The obtained maleimide-based copolymer (1-
Table 1 shows the physical properties of 3).

<Comparative Example 1> A 2 L flask was purged with nitrogen.
53 parts of methyl isobutyl ketone (MIBK) and 1.0 part of α-methylstyrene dimer were charged, and the polymerization system was heated to 110 ° C.
And the MIBK starts refluxing, and then the initiator t-
Butyl peroxyisopropyl carbonate 0.004
3 parts and 0.0043 part of t-butyl peroxyisopropyl carbonate and M
13 parts of styrene, 11 parts of methacrylic acid, N-cyclohexylmaleimide (CH
MI) 13 parts were dissolved in MIBK 8 parts at 60 ° C. and continuously supplied over 3 hours, and the polymerization was further continued for 2 hours. After diluting the polymerization solution with MIBK, the mixture was poured into hexane to precipitate the maleimide-based copolymer (1
-4) was obtained. The obtained maleimide-based copolymer (1-
Table 1 shows the physical properties of 4).

Example 4 The polymerization solution obtained in Example 2 was introduced into a twin-screw extruder equipped with a vent as a devolatilizer without dilution with MIBK, and devolatilized at 180 ° C. under reduced pressure. ,
The maleimide-based copolymer was extruded with an extruder, and the obtained strand was pulverized to obtain a maleimide-based copolymer (1-
5) was obtained. The obtained maleimide-based copolymer (1-5)
Table 1 shows the physical properties of the compound.

<Example 5> The initial charge of styrene was 7.
5 parts, 10 parts of methacrylic acid, 7.5 drops of styrene
Parts, methacrylic acid was changed to 10 parts and CHMI was changed to 15 parts, and the same operation as in Production Example 1 was performed to obtain a maleimide copolymer (1-6). Table 1 shows the physical properties of the obtained maleimide copolymer (1-6). In addition, the residual volatile matter in the table is the total amount of the remaining monomer and the solvent other than the maleimide-based monomer.

[0047]

[Table 1]

Reference Example The maleimide-based copolymer (1-2) obtained in Example 2 was dissolved in cellosolve acetate, applied on a glass plate using a die coater, dried naturally for 2 days, and dried for 120 days. By drying at ℃ for 2 hours,
A film having a thickness of 50 μm was obtained. This film was colorless and transparent, and had no problem such as discoloration even when left in an oven at 240 ° C. for 1 hour. Also, the film in this reference example,
An alkali aqueous solution solubility test was performed under the same conditions as in the above example, and it was confirmed that the alkali insoluble content was 0.

[0049]

The present invention provides a maleimide copolymer obtained by polymerizing monomer components including an N-substituted maleimide monomer, an aromatic vinyl monomer and an unsaturated monocarboxylic acid monomer. By devising the supply method of the monomer component, the content of the trimer composed of the N-substituted maleimide monomer and the aromatic vinyl monomer is small, and the composition distribution is small. A maleimide-based copolymer composition having excellent solubility can be obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Yamaguchi 5-8 Nishiburi-cho, Suita-shi, Osaka Nippon Shokubai Co., Ltd. F-term (reference) 4J011 BB01 BB07 BB08 BB15 BB17 4J100 AB02Q AB03Q AB04Q AB08Q AJ02R AM45P AM47P AM48P AM49P BB01P BC04P BC43P BC49P CA05 DA01 FA19 FA35

Claims (4)

[Claims] 1. An N-substituted maleimide monomer (a) 10 to 8
0% by weight, 10 to 80% by weight of an aromatic vinyl monomer (b) and 1 to 70% of an unsaturated monocarboxylic acid monomer (c)
A maleimide-based copolymer obtained by polymerizing a monomer component containing 1% by weight of a maleimide-based copolymer, wherein an insoluble content of an aqueous alkali solution is 10% by weight or less. 2. N-substituted maleimide monomers (a) 10 to 8
0% by weight, 10 to 80% by weight of an aromatic vinyl monomer (b) and 1 to 70% of an unsaturated monocarboxylic acid monomer (c)
A maleimide-based copolymer obtained by polymerizing a monomer component containing 1% by weight, wherein the content of the compound (2) having a specific structure represented by the following general formula (1) is 10% by weight or less. Characterized maleimide-based copolymer (1). Embedded image (However, in the general formula (1), R ¹ independently represents an alkyl group, a cycloalkyl group, an aryl group, an alkyl-substituted aryl group or a halogen-substituted aryl group; R ² represents hydrogen or a methyl group; ^{3 to} R ⁶ each independently represent hydrogen, an alkyl group, a cycloalkyl group, a cycloalkyl group, an aryl group, an alkyl-substituted aryl group or a halogen-substituted aryl group. 3. N-substituted maleimide monomers (a) 10 to 8
0% by weight, 10 to 80% by weight of an aromatic vinyl monomer (b) and 1 to 70% of an unsaturated monocarboxylic acid monomer (c)
In a method for producing a maleimide-based copolymer (1) obtained by polymerizing a monomer component containing 1% by weight, a monomer (b) and a monomer (c) and, if necessary, a solvent are added to a reactor. After the supply, the polymerization is started while the remaining monomer (b) and monomer (c) and the monomer (a) are continuously or intermittently fed into the polymerization system. A method for producing a maleimide-based copolymer, characterized in that: 4. After supplying the monomers (b) and (c) and, if necessary, a solvent to the reactor, polymerization is started and the remaining monomers (b) and (c) ) And the monomer (a) and the monomer (b) are supplied without prior mixing during the polymerization reaction while the monomer (a) is continuously or intermittently supplied into the polymerization system. The method for producing a maleimide-based copolymer according to claim 3, wherein