JP2000204126A - New maleimide-based copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new maleimide-based copolymer having high weather resistance and good mixing property with other resin and excellent in high heat resistance, low water absorbency, etc., by introducing an ether structure into the structure of a maleimide-based resin. SOLUTION: This new maleimide-based copolymer comprises (A) a maleimide structural unit represented by formula I (R1 and R2 are each H or an alkyl; X is H, a halogen, an alkyl or the like) and (B) a 5-membered ring ether structural unit represented by formula II (R3 to R8 are each H or an alkyl) in a structure. Furthermore, the structural unit B is arranged alternately with the structural unit A. The copolymer is preferably obtained by compounding and copolymerizing a maleimide-based monomer represented by formula III with a dihydrofuran-based monomer represented by formula IV in a solvent such as tetrahydrofuran in the presence of a polymerization initiator, etc., such as azobisisobutyronitrile at 0-200 deg.C reaction temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a novel maleimide-based copolymer containing a 5-membered ring ether structural unit in the structure and a method for producing the same.

[0002]

2. Description of the Related Art Since a maleimide resin has excellent heat resistance, it constitutes a heat resistant resin composition by itself.
It is widely used to improve the heat resistance of a resin composition containing, as a main component, another resin having excellent properties other than heat resistance such as transparency and thermoplasticity.

However, a maleimide-based resin is insoluble in a general-purpose solvent if the maleimide homopolymer or the maleimide content is large, making it difficult to produce or purify the polymer. When a maleimide and another monomer are copolymerized, It is necessary to select and use a monomer having good copolymerizability due to the problem of polymerizability, and furthermore, if another monomer having low heat resistance or low transparency is used, the maleimide has excellent heat resistance. When it is used in combination with other resins, there is a problem of compatibility with other resins, and it is difficult to control only with maleimide. It is difficult, and other monomers must be selected. Therefore, improvement is desired.

Hitherto, these problems have been solved by copolymerizing styrene or methyl methacrylate. However, the heat resistance of styrene and methyl methacrylate themselves is not so high (both glass transition temperatures are about 100 ° C.), and the improvement method by these methods has poor weather resistance in the case of styrene, and maleimide in the case of methyl methacrylate. Is not so good.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a maleimide-based copolymer which does not have such another problem and which is newly improved, and a method for producing the same.

[0006]

Means for Solving the Problems The present inventor has conducted various studies on improving the above-mentioned problems of the maleimide resin, and as a result, if an ether structure is introduced into the structure of the maleimide resin, the ether structure is improved. By having such properties as high weather resistance and good miscibility with other resins, it is possible to solve the above-mentioned problems of the maleimide resin, in which case, if a cyclic ether structure is introduced, high heat resistance, low water absorption and It is thought that the advantages described above can be obtained together, further studied, and as a result of repeated experiments, it has been found that it is sufficient to introduce a 5-membered ring ether structural unit represented by the following general formula (2). completed.

Accordingly, the novel maleimide-based copolymer according to the present invention comprises, in its structure, a maleimide structural unit represented by the following general formula (1):

[0008]

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In addition, 5 represented by the following general formula (2)
Membered ring ether structural unit,

[0010]

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[0011] Further, the method for producing a maleimide-based copolymer according to the present invention comprises mixing a maleimide-based monomer represented by the following general formula (3) with a dihydrofuran-based monomer represented by the following general formula (4). This is a method of copolymerizing.

[0012]

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[0013]

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In the above general formulas (1) and (3), R ¹ and R ² are each independently a hydrogen atom or an alkyl group, and X is a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group. , A phenyl group, a cyano group or a hydroxyl group. Further, the above general formula (2),
In (4), R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom or an alkyl group.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The novel maleimide-based copolymer according to the present invention (hereinafter referred to as the maleimide-based copolymer of the present invention) includes, in addition to the maleimide-based structural unit represented by the general formula (1), And a five-membered ring ether structural unit represented by the general formula (2). The maleimide-based structural unit of the general formula (1) is, for example, a structure obtained by polymerizing a maleimide-based monomer represented by the general formula (3), and has a 5-membered ring ether structure of the general formula (2). The unit is, for example, a structure obtained by polymerizing a dihydrofuran-based monomer represented by the general formula (4).

In the maleimide copolymer of the present invention,
The arrangement structure of the structural units (1) and (2) constituting the polymer is not limited, and may be any one of a random structure, a block structure, an alternating structure, and the like. From the viewpoint of improvement, an alternately arranged structure (alternate copolymer) is particularly preferred. Structural unit (1) in the maleimide-based copolymer of the present invention: structural unit (2)
Is preferably 1: 9 to 9: 1, more preferably 3: 7 to 7: 3, and still more preferably 6: 4 to 4: 6.

The maleimide-based copolymer of the present invention may contain third and fourth structural units such as styrene and methyl methacrylate in addition to the above two structural units, but is not particularly limited. Although the molecular weight of the maleimide-based copolymer of the present invention is not limited, it is preferably from 1,000 to 1,000,000, and particularly preferably from 3,000 to 200,000. If the molecular weight is lower than 1,000, disadvantageous circumstances such as deterioration of physical properties such as heat resistance of the copolymer may occur.

The dihydrofuran of the general formula (4), which is a cyclic unsaturated ether, has high polymerizability when a cationic catalyst is used, but easily undergoes radical copolymerization when the partner is a maleimide compound. Radical polymerization is also possible. Therefore, according to the method of the present invention described below, it becomes easy to introduce the 5-membered ring ether structural unit into the structure of the maleimide-based polymer. However, the maleimide-based copolymer of the present invention may be produced by other methods.

The general formula (3) used in the method of the present invention
As the maleimide-based monomer represented by, maleimide,
N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-chlorophenylmaleimide, N-methyl Phenylmaleimide, N-naphthylmaleimide, N-laurylmaleimide, N-hydroxylethylmaleimide,
N-hydroxylphenylmaleimide, N-methoxyphenylmaleimide, N-carboxyphenylmaleimide, N-nitrophenylmaleimide, N-tribromophenylmaleimide, and the like.
Seeds or two or more kinds are used. Among these, N-cyclohexylmaleimide, N-isopropylmaleimide,
N-phenylmaleimide is preferred.

The general formula (4) used in the method of the present invention:
As the dihydrofuran-based monomer represented by, for example,
Examples include compounds having the following structure,

[0021]

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Among them, a group of compounds having the following structure is preferred.

[0023]

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The method of polymerizing the maleimide-based copolymer according to the present invention may be, for example, any of bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, but is not particularly limited. The mixing ratio of the dihydrofuran monomer to the maleimide monomer during the polymerization reaction (dihydrofuran monomer /
Maleimide-based monomer, molar ratio) is preferably 5 to 1, more preferably 4 to 1.2.

The temperature at which the polymerization reaction is carried out is preferably from 0 to 200 ° C., particularly preferably from 25 to 150 ° C. The polymerization temperature is 0
When the temperature is lower than 200C, the polymerization reaction becomes extremely slow, and when the temperature exceeds 200C, the reaction becomes so severe that control becomes difficult. Solvents for the polymerization reaction include aliphatic hydrocarbons such as hexane and octane; alicyclic saturated hydrocarbons such as cyclohexane; alicyclic unsaturated hydrocarbons such as cyclohexene; and aromatics such as benzene, toluene and xylene. Hydrocarbons; ketones such as acetone and methyl ethyl ketone; methyl acetate, ethyl acetate, butyl acetate, γ
Esters such as butyrolactone; dichloroethane,
Halogenated hydrocarbons such as chloroform and carbon tetrachloride; ethers such as dimethyl ether, tetrahydrofuran, dioxane and dioxolane; ethers of alkylene glycol such as propylene glycol monomethyl ether acetate and diethylene glycol monomethyl ether acetate; methyl alcohol, ethyl alcohol and butyl Alcohol, isopropyl alcohol,
Alcohols such as ethylene glycol and propylene glycol monomethyl ether; dimethylformamide;
Amides such as N-methylpyrrolidone; sulfonic acid esters such as dimethyl sulfoxide; carbonates such as dimethyl carbonate and diethyl carbonate; alicyclic carbonates such as ethylene carbonate and propylene carbonate; water; Preferred are the above-mentioned aliphatic hydrocarbons, aromatic hydrocarbons, esters, ethers, alcohols and amides.

The amount of the solvent used is not particularly limited, but is preferably such that the concentration of the total amount of the maleimide monomer and the dihydrofuran monomer is 10 to 80% by weight. As the polymerization initiator, azobisisobutyronitrile, azobis (2
An azo compound such as-(methyl) butyronitrile and dimethyl azobis (isobutyrate), and a peroxide such as benzoyl peroxide and ditert-butyl peroxide are used. The amount of the polymerization initiator used is not particularly limited,
0.001 to 10% by weight based on the monomer,
It is more preferably 0.01 to 5% by weight, and still more preferably 0.1 to 3% by weight. If the amount of the polymerization initiator is less than 0.001% by weight, the polymerization reaction tends to be extremely slow, and if it exceeds 10% by weight, there is a problem that the polymerization reaction becomes intense and the reaction control becomes difficult. Is also not preferred.

At the time of polymerization, a chain transfer agent such as lauryl captan or meltcaptoethanol or a regulator may be used as necessary. When introducing the third and fourth structural units into the maleimide-based copolymer according to the present invention,
A polymerizable monomer such as styrene or methyl methacrylate may be used in combination.

The method for purifying the maleimide-based copolymer obtained by the method of the present invention is not limited.
Dialysis, centrifugation, solvent removal by drying under reduced pressure, and the like are employed. The novel maleimide-based copolymer according to the present invention,
Since it has characteristics such as high weather resistance, low water absorption and high heat resistance derived from the dihydrofuran-based structural unit, it is useful for molded articles, films, sheets, optical materials, fibers, resin modifiers and the like.

[0029]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 100 parts by weight of 2,3-dihydrofuran (hereinafter, referred to as DHF) and cyclohexylmaleimide (hereinafter, referred to as CHMI) were placed in a reactor equipped with a thermometer, a cooling pipe, a nitrogen gas introducing pipe, and a stirrer. After charging 60 parts by weight and 100 parts by weight of tetrahydrofuran, the inside of the reactor was purged with nitrogen gas. Next, the temperature of the reaction solution in the reactor was raised to 60 ° C. while stirring, and then 2,2′-azobis (isobutyric acid) dimethyl (hereinafter referred to as MAIB) was used as a polymerization initiator.
One part by weight was added to carry out a polymerization reaction.

Five hours after the start of the reaction, a part of the reaction solution in the reactor was withdrawn, and after confirming the disappearance of CHMI by gas chromatography, the reactor was cooled to room temperature and the reaction solution was removed from the reactor. Removed and poured into 10 volumes of methanol. A white solid precipitated in this liquid was separated by filtration, and then sufficiently washed with methanol. The resulting white solid, which was the produced polymer, was purified by repeating the reprecipitation operation two to three times using a mixed solvent of toluene and methanol, and then dried under reduced pressure.

The yield of the polymer obtained as a white solid after drying was 82 parts by weight. From NMR and IR, this polymer was found to be poly (2,3-dihydrofuran-cyclohexylmaleimide) (hereinafter referred to as P (DHF-
CHMI)). The IH-NMR of this polymer in Figure 1, the ¹³ C-NMR in Fig. 2, also I
R is shown in FIG. The molecular weight of the polymer measured by GPC (gel permeation chromatography) was 35,000 as a weight average molecular weight (Mw). Further, according to thermogravimetric analysis (TGA), the thermal decomposition onset temperature is 350 ° C., and according to differential thermal scanning analysis (DSC),
The glass transition temperature was 215 ° C. This polymer is
It was insoluble in water, methanol, acetone, etc., and soluble in tetrahydrofuran, toluene, etc. Example 2 A reactor equipped with a thermometer, a cooling pipe, a nitrogen gas introducing pipe and a stirrer was charged with 100 parts by weight of DHF and CHMI.
After charging 60 parts by weight and 100 parts by weight of tetrahydrofuran, the inside of the reactor was purged with nitrogen gas. Next, the polymerization reaction was carried out at room temperature as it was while stirring the reaction solution in the reactor. After a lapse of 24 hours from the start of the reaction, the disappearance of CHMI was confirmed in the same manner as in Example 1, and then the reaction solution was taken out of the reactor and poured into a 10-fold amount of methanol. A white solid filtered out of this liquid was subjected to washing with methanol, reprecipitation with a mixed solvent of toluene and methanol, and drying under reduced pressure as in Example 1, to obtain a polymer. The polymer yield was 75 parts by weight.

The polymer obtained as a white solid was confirmed to be P (DHF-CHMI) by NMR and IR. According to GPC, the weight average molecular weight (Mw) of the polymer was 40,000. The thermal decomposition onset temperature of this polymer is 345 ° C from TGA, and the glass transition temperature is D
It was measured as 210 ° C. by SC. Further, this polymer was insoluble in water, methanol, acetone and the like, and was soluble in tetrahydrofuran, toluene and the like. Example 3 A polymerization reaction was carried out in the same manner as in Example 1 except that the amount of DHF charged was changed to 50 parts by weight, and P (DHF-C
HMI). The polymer yield was 70 parts by weight. The weight average molecular weight (Mw) of the obtained polymer is 35,000.
Met. The thermal decomposition onset temperature of this polymer was measured at 345 ° C. by TGA, and the glass transition temperature was measured at 210 ° C. by DSC. Further, this polymer was insoluble in water, methanol, acetone and the like, and was soluble in tetrahydrofuran, toluene and the like. Example 4 Example 1 was the same as Example 1 except that CHMI was changed to phenylmaleimide (hereinafter referred to as PMI).
A polymerization reaction was carried out in the same manner as in the above to obtain P (DHF-PMI). The polymer yield was 70 parts by weight. 1H-NMR and ¹³ C-NMR of this polymer are shown in FIG.
R is shown in FIG. The weight average molecular weight (Mw) of the obtained polymer was 35,000. The thermal decomposition onset temperature of this polymer was measured at 340 ° C. by TGA, and the glass transition temperature was measured at 200 ° C. by DSC. Further, this polymer was insoluble in water, methanol, acetone and the like, and was soluble in tetrahydrofuran, toluene and the like.

[0033]

The novel maleimide-based copolymer according to the present invention has an ether structure in the structure, so that it does not dissolve in the general-purpose solvent of the maleimide-based homopolymer and has compatibility with other resins. Does not have the problem of being bad. In addition, since the ether structure is a cyclic structure, it can exhibit characteristics such as high weather resistance, low water absorption, and high heat resistance.

According to the method for producing a maleimide copolymer according to the present invention, the novel maleimide copolymer can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a 1H-NMR chart of a polymer of Example 1.

FIG. 2 is a ¹³ C-NMR chart of a polymer of Example 1.

FIG. 3 is an IR chart of the polymer of Example 1.

FIG. 4 is a 1H-NMR chart of a polymer of Example 4.

FIG. 5 is a ¹³ C-NMR chart of a polymer of Example 4.

FIG. 6 is an IR chart of the polymer of Example 4.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 4J100 AM43P AM45P AM47P AM48P AM49P AR32Q BA03P BA05P BA16P BA41P BB01P BB03P BC04P BC49P CA04 DA22 DA36 DA37 FA03 FA04 JA32

Claims (3)

[Claims] 1. A maleimide structural unit represented by the following general formula (1): (Wherein R ¹ and R ² are each a hydrogen atom or an alkyl group, and X is a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, a phenyl group, a cyano group or a hydroxyl group). In addition, a 5-membered ring ether structural unit represented by the following general formula (2): (Wherein R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom or an alkyl group). 2. The novel maleimide-based copolymer according to claim 1, wherein the 5-membered ring ether structural units are alternately arranged with the maleimide structural units. 3. A novel maleimide-based copolymer obtained by blending a maleimide-based monomer represented by the following general formula (3) with a dihydrofuran-based monomer represented by the following general formula (4) and copolymerizing the mixture. Manufacturing method. Embedded image (Wherein R ¹ and R ² are each independently a hydrogen atom or an alkyl group, and X is a hydrogen atom, a halogen atom,
It is an alkyl group, a cycloalkyl group, an alkenyl group, a phenyl group, a cyano group or a hydroxyl group. ) (In the formula, R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom or an alkyl group.)