JP6136508B2 - Diisopropyl fumarate-cinnamate-bismaleimide copolymer resin and method for producing the same - Google Patents

Description

  The present invention relates to a novel diisopropyl fumarate-cinnamate-bismaleimide copolymer resin and a method for producing the same, and more specifically, a novel polymer having a high molecular weight that can be applied to a film having excellent toughness. The present invention relates to a diisopropyl fumarate-cinnamate-bismaleimide copolymer resin and a method for efficiently producing the same.

  A liquid crystal display is widely used as a most important display device in a multimedia society, such as a mobile phone, a computer monitor, a notebook computer, and a television. Many optical films are used for improving the display characteristics of the liquid crystal display. In particular, the retardation film plays a major role in improving contrast and compensating for color tone when viewed from the front or obliquely. As the conventional retardation film, polycarbonate or cyclic polyolefin is used, and these polymers are polymers having positive birefringence.

  A polymer having negative birefringence includes an acrylic resin and polystyrene, but the acrylic resin has a small retardation, and the characteristics as a retardation film are not sufficient. Polystyrene has a large photoelastic coefficient in the low-temperature region, so the phase difference changes due to slight stress, the problem of stability of the phase difference, the problem of optical properties such as the large wavelength dependence of the phase difference, and heat resistance However, it is not used at present.

  In response to market demand for retardation films having negative birefringence, fumaric acid diester resins and films made thereof have been proposed (see, for example, Patent Documents 1 to 5).

JP 2008-112141 A JP 2012-032784 A WO2012 / 005120 JP 2008-129465 A JP 2006-193616 A

  While the fumaric acid diester resin proposed in Patent Documents 1 to 5 and a film comprising the same express high out-of-plane retardation, while maintaining the characteristics as a film even in a thin film, There is a demand for the appearance of resins that exhibit higher out-of-plane retardation.

  An object of the present invention is to provide a novel high-molecular-weight diisopropyl fumarate-cinnamate-bismaleimide copolymer resin having excellent toughness even when used as a film, and a method for efficiently producing the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that a specific diisopropyl fumarate-cinnamate-bismaleimide copolymer resin can solve the above problems, and have completed the present invention. It was.

  That is, the present invention includes diisopropyl fumarate-cinnamon, comprising a diisopropyl fumarate residue unit, a cinnamic acid ester residue unit having an alkyl group having 1 to 6 carbon atoms, and a bismaleimide residue unit. The present invention relates to an acid ester-bismaleimide copolymer resin and a method for producing the same.

  Hereinafter, the diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention will be described in detail.

  The diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention comprises a diisopropyl fumarate residue unit, a cinnamic acid ester residue unit having an alkyl group having 1 to 6 carbon atoms, and a bismaleimide residue unit. It is a diisopropyl fumarate-cinnamate-bismaleimide copolymer resin.

  Here, the C1-C6 alkyl group in the cinnamic acid ester residue unit having a C1-C6 alkyl group is independent, for example, a methyl group, an ethyl group, an n-propyl group, Examples include isopropyl group, n-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group and the like. These may be substituted with halogen groups such as fluorine and chlorine; ether groups; ester groups or amino groups. Examples of the cinnamate residue unit having an alkyl group having 1 to 6 carbon atoms include those derived from a cinnamate ester having an alkyl group having 1 to 6 carbon atoms. And as a cinnamic acid ester having a C 1-6 alkyl group, for example, methyl cinnamate, ethyl cinnamate, n-propyl cinnamate, isopropyl cinnamate, n-butyl cinnamate, Examples thereof include isobutyl cinnamate, t-butyl cinnamate, n-pentyl cinnamate, and n-hexyl cinnamate. These may be contained alone or in combination of two or more. Among them, in particular, it is possible to efficiently obtain a diisopropyl fumarate-cinnamate-bismaleimide copolymer resin having a high molecular weight, so that methyl cinnamate residue units, ethyl cinnamate residues The unit is preferably an isopropyl cinnamate residue unit.

  In addition, the bismaleimide residue unit may be any of aromatic bismaleimide and / or aliphatic maleimide. The diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention comprises a bismaleimide residue unit, so that a higher molecular weight can be achieved. The polymerization conversion rate of the monomer is also high, and the productivity efficiency is also excellent. Moreover, when the obtained diisopropyl fumarate-cinnamate-bismaleimide copolymer resin is used as a film, it becomes a film having excellent toughness.

  Examples of the bismaleimide include 4-methyl-1,3-phenylene bismaleimide, 1,3-phenylene bismaleimide, 1,4-phenylene bismaleimide, 1,2-phenylene bismaleimide, and naphthalene-1,5-dimaleimide. 4-chloro-1,3-phenylene bismaleimide, 4,4′-diphenylmethane bismaleimide, N, N ′-(4,4′-biphenylene) bismaleimide, N, N ′-(sulfonyldi-p-phenylene ) Bismaleimide, N, N ′-(oxydi-p-phenylene) bismaleimide, N, N ′-(3,3′-dimethyl-4,4′-biphenylylene) bismaleimide, N, N ′-(benzylidene) -P-phenylene) bismaleimide, 3,3'-dichloro-4,4'-diphenylmethane bismaleimide, 3,3'- Dimethyl-4,4′-diphenylmethane bismaleimide, 3,3′-dimethoxy-4,4′-diphenylmethane bismaleimide, 4,4′-diphenyl sulfide bismaleimide, 4,4′-diphenyl ether bismaleimide, 3,3 ′ -Benzophenone bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 1,1 '-[1,4-butanediylbis (oxy-p-phenylene)] bismaleimide, 2,2-bis [4- (4-maleimidophenoxy) phenyl] propane, bis [4-maleimido (4-phenoxyphenyl)] sulfone, 1,1 ′-[1,4-phenylenebis (oxy-4,1) -Phenylene)] bismaleimide, 1,1 ′-[sulfonylbis (4,1-phenyleneoxy-3, 1-phenylene)] bismaleimide, bis [4- (3-maleimidophenoxy) phenyl] ketone, 1,3-bis (4-maleimidophenoxy) benzene, 1,3-bis (3-maleimidophenoxy) benzene, 1, 1 ′-[oxybis (4,1-phenylenethio-4,1-phenylene)] bismaleimide, 1,1 ′-[(2,2 ′, 3,3 ′, 5,5 ′, 6,6′- Octafluoro [1,1′-biphenyl] -4,4′-diyl) bis (oxy-3,1-phenylene)] bismaleimide, 1,6-bismaleimide- (2,2,4-trimethyl) hexane, 1,6-bismaleimide- (2,4,4-trimethyl) hexane, N, N′-decamethylene bismaleimide, N, N′-octamethylene bismaleimide, N, N′-heptamethylene bisma Reimide, N, N′-hexamethylene bismaleimide, N, N′-pentamethylene bismaleimide, N, N′-tetramethylene bismaleimide, N, N′-trimethylene bismaleimide, N, N′-ethylene bismaleimide N, N '-(oxydimethylene) bismaleimide, 1,13-bismaleimide-4,7,10-trioxatridecane, 1,11-bis (maleimide) -3,6,9-trioxaundecane Etc., and one or more of these may be contained.

  The diisopropyl fumarate-cinnamate-bismaleimide copolymer resin may contain other monomer residue units as long as it does not exceed the scope of the present invention. For example, styrene residue units such as styrene residue units and α-methylstyrene residue units; (meth) acrylic acid residue units; (meth) methyl acrylate residue units, (meth) acrylate ethyl Residual units, (meth) acrylic acid ester residue units such as butyl (meth) acrylate residue units; Vinyl ester residue units such as vinyl acetate residue units and vinyl propionate vinyl residue units; Acrylonitrile residue units Methacrylonitrile residue unit; vinyl ether residue unit such as methyl vinyl ether residue unit, ethyl vinyl ether residue unit, butyl vinyl ether residue unit; N-substituted maleimide residue units such as lumaleimide residue units, N-cyclohexylmaleimide residue units and N-phenylmaleimide residue units; olefin residue units such as ethylene residue units and propylene residue units; fumaric acid Examples thereof include one or more selected from fumaric acid diester residue units other than diisopropyl fumarate residue units such as di-n-butyl residue units and bis (2-ethylhexyl) fumarate residue units. .

  The composition of the diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention is excellent in solubility in a solvent and the like, and is a high molecular weight diisopropyl fumarate-cinnax having excellent strength and toughness when used as a film. Since it becomes an acid ester-bismaleimide copolymer resin, a cinnamic acid ester residue unit having an alkyl group having 1 to 6 carbon atoms and a diisopropyl fumarate residue unit of 50 to 98.5 mol%, 1 to 49.5 mol And bismaleimide residue units of 0.01 to 0.5% are preferred, cinnamate ester residues having a diisopropyl fumarate residue unit of 69.7 to 96.7 mol% and an alkyl group having 1 to 6 carbon atoms More preferred are 3 to 30 mol% of units and 0.01 to 0.3 mol% of bismaleimide residue units.

  Since the diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention is excellent in mechanical properties, strength and toughness when used as a film, gel permeation chromatography (GPC) The number average molecular weight in terms of standard polystyrene obtained from the elution curve measured by the above is preferably 60000 to 500000, more preferably 70000 to 500000, particularly preferably 80000 to 300000, and 90000 to 300000. Most preferred.

  The method for producing diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention may be produced by any method as long as diisopropyl fumarate-cinnamate-bismaleimide copolymer resin is obtained. For example, it can be produced by radical polymerization of diisopropyl fumarate, a cinnamic acid ester having an alkyl group having 1 to 6 carbon atoms, and bismaleimide. And the cinnamic acid ester having an alkyl group having 1 to 6 carbon atoms in that case includes a compound for inducing the above-described cinnamic acid ester residue unit having an alkyl group having 1 to 6 carbon atoms. it can. Examples of the bismaleimide include the bismaleimide described above.

  For the radical polymerization, any known polymerization method, for example, bulk polymerization method, solution polymerization method, suspension polymerization method, precipitation polymerization method or emulsion polymerization method can be employed.

  Examples of the radical polymerization initiator used for radical polymerization include benzoyl peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, and dicumyl peroxide. Organic peroxides such as oxide, t-butylperoxyacetate, t-butylperoxybenzoate; 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-butyronitrile), Examples thereof include azo initiators such as 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate, and 1,1′-azobis (cyclohexane-1-carbonitrile).

And there is no restriction | limiting in particular as a solvent which can be used in solution polymerization method, suspension polymerization method, precipitation polymerization method, emulsion polymerization method, For example, aromatic solvents, such as benzene, toluene, xylene; Methanol, ethanol, propanol, butanol, etc. Cyclohexane, dioxane, tetrahydrofuran, acetone, methyl ethyl ketone, dimethylformamide, isopropyl acetate, water and the like, and mixed solvents thereof.

  In addition, the polymerization temperature at the time of performing radical polymerization can be appropriately set according to the decomposition temperature of the radical polymerization initiator, and the reaction is easily controlled. Preferably it is done.

  Furthermore, when producing the diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention, a higher molecular weight diisopropyl fumarate-cinnamate-bismaleimide copolymer resin is produced more efficiently. From 50 to 98.5 mol% diisopropyl fumarate, 1 to 49.5 mol% cinnamic acid ester having an alkyl group having 1 to 6 carbon atoms, 0.01 to 0.5 bismaleimide. It is preferable to carry out the radical polymerization reaction in the presence of 0.001 to 2 mol% of a radical polymerization initiator, with the total monomer containing at a mol% ratio of 100 mol%.

  The diisopropyl fumarate-cinnamate-bismaleimide copolymer resin of the present invention is excellent in solubility in a solvent and can be formed into a film by a method such as solution casting. The film has film strength, toughness, Excellent transparency and the like.

  The present invention provides a novel diisopropyl fumarate-cinnamic acid ester-bismaleimide copolymer resin and the diisopropyl fumarate-cinnamic acid ester-bismaleimide copolymer, which have excellent properties when used as a film or the like because of its high molecular weight. A method for efficiently producing a resin is provided.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

  In addition, the various physical properties shown by an Example were measured with the following method.

<Composition of diisopropyl fumarate-cinnamate-bismaleimide copolymer resin>
Using a nuclear magnetic resonance measuring apparatus (manufactured by JEOL, trade name JNM-GX270), it was determined by proton nuclear magnetic resonance spectroscopy ( ¹ H-NMR) spectrum analysis.

<Measurement of number average molecular weight>
Using a gel permeation chromatography (GPC) apparatus (manufactured by Tosoh Corporation, trade name C0-8011 (equipped with column GMH _HR- H)), tetrahydrofuran was measured as a solvent at 40 ° C., and the standard polystyrene equivalent value was obtained. Asked.

Example 1 (Production of diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin)
In a glass ampule with a capacity of 75 mL, 50 g (0.25 mol (95.02 mol%)) of diisopropyl fumarate, 2.3 g (0.013 mol (4.94 mol%)) of ethyl cinnamate, 1,4-phenylene 0.029 g (1.1 × 10 ⁻⁴ mol (0.04 mol%)) of bismaleimide and 0.29 g (0.0016 mol (0.61 mol%)) of tert-butyl peroxypivalate as a polymerization initiator ), And after repeating nitrogen substitution and depressurization, sealing was performed under reduced pressure. The ampule was placed in a thermostatic bath at 50 ° C. and held for 144 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved with 400 g of tetrahydrofuran. This polymer solution was dropped into 3 L of methanol and precipitated, and then vacuum-dried at 80 ° C. for 10 hours to obtain 28.6 g of diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer (recovery). Rate: 55%).

  The number average molecular weight of the obtained diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin was 112,000.

Further, by ¹ H-NMR measurement, the copolymer resin composition was found to be diisopropyl fumarate residue unit / ethyl cinnamate residue unit / bismaleimide residue unit = 94.98 / 4.98 / 0.04 (mol%). ) Confirmed.

  Diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin is dissolved in methyl isobutyl ketone to give a 15% by weight resin solution, cast on a 10 cm × 10 cm polyethylene terephthalate film by a coater, and at 130 ° C. for 10 minutes. By drying, a transparent film using a 30 μm thick diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin was obtained. When the bending test was carried out by bending the obtained film and bringing the ends into contact with each other, cracks were not found in the diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin layer, and the toughness was excellent. there were.

Example 2 (Production of diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin)
In a glass ampule with a capacity of 75 mL, diisopropyl fumarate 50 g (0.25 mol (85.23 mol%)), ethyl cinnamate 7.6 g (0.043 mol (14.66 mol%)), 4,4′- 0.11 g (3.1 × 10 ⁻⁴ mol (0.11 mol%)) of diphenylmethane bismaleimide and 0.32 g (0.0018 mol (0.61 mol%) of tert-butyl peroxypivalate as a polymerization initiator )), And after repeating nitrogen substitution and depressurization, it was sealed under reduced pressure. The ampule was placed in a thermostatic bath at 50 ° C. and held for 144 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved with 400 g of tetrahydrofuran. This polymer solution was dropped into 3 L of methanol and precipitated, and then vacuum-dried at 80 ° C. for 10 hours to obtain 31.1 g of diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer (recovery). (Rate: 56%).

  The number average molecular weight of the obtained diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin was 121,000.

The copolymer resin composition was determined by ¹ H-NMR measurement to be diisopropyl fumarate residue unit / ethyl cinnamate residue unit / bismaleimide residue unit = 85.24 / 14.66 / 0.1 (mol%). ) Confirmed.

  When the obtained diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin was made into a film by the same method as in Example 1 and subjected to a bending test, no cracking or the like was found in the obtained transparent film, It was excellent in toughness.

Example 3 (Production of diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin)
In a glass ampule with a capacity of 75 mL, diisopropyl fumarate 50 g (0.25 mol (69.84 mol%)), ethyl cinnamate 18.9 g (0.107 mol (29.89 mol%)), 4-methyl-1 , 3-phenylenebismaleimide 0.27 g (9.6 × 10 ⁻⁴ mol (0.27 mol%)) and 0.39 g (0.0023 mol (0.0023 mol) of tert-butyl peroxypivalate as a polymerization initiator). 64 mol%)) was added, nitrogen substitution and depressurization were repeated, and the mixture was sealed under reduced pressure. The ampoule was placed in a thermostatic bath at 50 ° C. and held for 168 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved with 400 g of tetrahydrofuran. This polymer solution was dropped into 3 L of methanol and precipitated, and then vacuum dried at 80 ° C. for 10 hours to obtain 37.9 g of diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer (recovery). Rate: 55%).

  The number average molecular weight of the obtained diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer was 142,000.

Further, by ¹ H-NMR measurement, the copolymer resin composition was diisopropyl fumarate residue unit / ethyl cinnamate residue unit / bismaleimide residue unit = 69.92 / 29.81 / 0.27 (mol%). ) Confirmed.

  When the obtained diisopropyl fumarate-ethyl cinnamate-bismaleimide copolymer resin was made into a film by the same method as in Example 1 and subjected to a bending test, no cracking or the like was found in the obtained transparent film, It was excellent in toughness.

Example 4 (Production of diisopropyl fumarate-methyl cinnamate-bismaleimide copolymer resin)
In a glass ampule with a capacity of 75 mL, diisopropyl fumarate 50 g (0.25 mol (85.31 mol%)), methyl cinnamate 7.2 g (0.043 mol (14.67 mol%)), 3,3′- 0.028 g (6.3 × 10 ⁻⁵ mol (0.02 mol%)) of dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide and tert-butyl peroxypivalate as a polymerization initiator 0.16 g (0.0009 mol (0.31 mol%)) was added, and after nitrogen substitution and depressurization were repeated, the mixture was sealed under reduced pressure. The ampule was placed in a constant temperature bath at 46 ° C. and held for 168 hours for radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved with 400 g of tetrahydrofuran. This polymer solution was dropped into 3 L of methanol and precipitated, and then vacuum-dried at 80 ° C. for 10 hours to obtain 29.7 g of diisopropyl fumarate-methyl cinnamate-bismaleimide copolymer (recovery). (Rate: 52%).

  The number average molecular weight of the obtained diisopropyl fumarate-methyl cinnamate-bismaleimide copolymer resin was 99000.

Further, by ¹ H-NMR measurement, the copolymer resin composition was found to be diisopropyl fumarate residue unit / methyl cinnamate residue unit / bismaleimide residue unit = 85.98 / 14.0 / 0.02 (mol%). ) Confirmed.

  When the obtained diisopropyl fumarate-methyl cinnamate-bismaleimide copolymer resin was made into a film by the same method as in Example 1 and subjected to a bending test, no cracking or the like was found in the obtained transparent film. It was excellent in toughness.

Example 5 (Production of diisopropyl fumarate-isopropyl cinnamate-bismaleimide copolymer resin)
In a glass ampule with a capacity of 75 mL, diisopropyl fumarate 50 g (0.25 mol (85.22 mol%)), isopropyl cinnamate 8.4 g (0.043 mol (14.66 mol%)), 1,6-bis Maleimide- (2,2,4-trimethyl) hexane 0.11 g (3.5 × 10 ⁻⁴ mol (0.12 mol%)) and tert-butyl peroxypivalate 0.32 g (0 .0018 mol (0.61 mol%)) was added, and after nitrogen substitution and depressurization were repeated, the mixture was sealed under reduced pressure. The ampule was placed in a thermostatic bath at 50 ° C. and held for 144 hours to carry out radical polymerization. After completion of the polymerization reaction, the polymer was taken out from the ampoule and dissolved with 400 g of tetrahydrofuran. This polymer solution was dropped into 3 L of methanol and precipitated, and then vacuum-dried at 80 ° C. for 10 hours to obtain 33.3 g of diisopropyl fumarate-isopropyl cinnamate-bismaleimide copolymer (recovery). (Rate: 57%).

  The number average molecular weight of the obtained diisopropyl fumarate-isopropyl cinnamate-bismaleimide copolymer was 133,000.

Further, by ¹ H-NMR measurement, the copolymer resin composition was found to be diisopropyl fumarate residue unit / isopropyl cinnamate residue unit / bismaleimide residue unit = 85.23 / 14.64 / 0.13 (mol%). ) Confirmed.

  When the obtained diisopropyl fumarate-isopropyl cinnamate-bismaleimide copolymer resin was made into a film by the same method as in Example 1 and subjected to a bending test, no cracking or the like was found in the obtained transparent film. It was excellent in toughness.

Comparative Example 1
17 g of diisopropyl fumarate-ethyl cinnamate copolymer was obtained in the same manner as in Example 1 except that 1,4-phenylenebismaleimide was not used (yield: 33%).

The number average molecular weight of the obtained diisopropyl fumarate-ethyl cinnamate copolymer was as low as 74000, and the yield was as extremely low as 33%. ^The copolymer composition obtained by ¹ H-NMR measurement was diisopropyl fumarate residue unit / ethyl cinnamate residue unit = 95/5 (mol%).

  The obtained diisopropyl fumarate-ethyl cinnamate copolymer was formed into a film by the same method as in Example 1 and subjected to a bending test. As soon as bending stress was applied, diisopropyl fumarate-ethyl cinnamate copolymer was obtained. Cracks occurred in the polymer layer.

Comparative Example 2
Except not using 4,4'-diphenylmethane bismaleimide, 8 g of diisopropyl fumarate-ethyl cinnamate copolymer was obtained in the same manner as in Example 2 (yield: 15%).

The number average molecular weight of the obtained diisopropyl fumarate-ethyl cinnamate copolymer was as low as 55000, and the yield was as low as 15%. ^The copolymer composition obtained by ¹ H-NMR measurement was diisopropyl fumarate residue unit / ethyl cinnamate residue unit = 83/17 (mol%).

  The obtained diisopropyl fumarate-ethyl cinnamate copolymer was formed into a film by the same method as in Example 1 and subjected to a bending test. As soon as bending stress was applied, diisopropyl fumarate-ethyl cinnamate copolymer was obtained. Cracks occurred in the polymer layer.

Comparative Example 3
13 g of diisopropyl fumarate-ethyl cinnamate copolymer was obtained in the same manner as in Example 3 except that 4-methyl-1,3-phenylenebismaleimide was not used (yield: 19%).

The number average molecular weight of the obtained diisopropyl fumarate-ethyl cinnamate copolymer was as low as 61000, and the yield was as low as 19%. ^The copolymer composition obtained by ¹ H-NMR measurement was diisopropyl fumarate residue unit / ethyl cinnamate residue unit = 71/29 (mol%).

  The obtained diisopropyl fumarate-ethyl cinnamate copolymer was formed into a film by the same method as in Example 1 and subjected to a bending test. As soon as bending stress was applied, diisopropyl fumarate-ethyl cinnamate copolymer was obtained. Cracks occurred in the polymer layer.

Comparative Example 4
5 g diisopropyl fumarate-methyl cinnamate copolymer was prepared in the same manner as in Example 4 except that 3,3′-dimethyl-5,5′-diethyl-4,4′-diphenylmethane bismaleimide was not used. (Yield: 8%) was obtained.

The number average molecular weight of the obtained diisopropyl fumarate-methyl cinnamate copolymer was as low as 78000, and the yield was as extremely low as 8%. The copolymer composition obtained by ¹ H-NMR measurement was diisopropyl fumarate residue unit / methyl cinnamate residue unit = 86/14 (mol%).

  The obtained diisopropyl fumarate-methyl cinnamate copolymer was made into a film by the same method as in Example 1 and subjected to a bending test. As soon as bending stress was applied, diisopropyl fumarate-methyl cinnamate copolymer Cracks occurred in the polymer layer.

Comparative Example 5
11 g of diisopropyl fumarate-isopropyl cinnamate copolymer was obtained in the same manner as in Example 5 except that 1,6-bismaleimide- (2,2,4-trimethyl) hexane was not used. (Rate: 18%).

The number average molecular weight of the obtained diisopropyl fumarate-isopropyl cinnamate copolymer was as low as 50,000, and the yield was as extremely low as 18%. The copolymer composition obtained by ¹ H-NMR measurement was diisopropyl fumarate residue unit / isopropyl cinnamate residue unit = 85/15 (mol%).

  The obtained diisopropyl fumarate-isopropyl cinnamate copolymer was made into a film by the same method as in Example 1 and subjected to a bending test. As soon as bending stress was applied, diisopropyl fumarate-isopropyl cinnamate copolymer was used. Cracks occurred in the polymer layer.

  The present invention provides a novel high-molecular-weight diisopropyl fumarate-cinnamate-bismaleimide copolymer resin and a method for efficiently producing the diisopropyl fumarate-cinnamate-bismaleimide copolymer resin. The diisopropyl fumarate-cinnamate-bismaleimide copolymer resin can provide a transparent film having excellent strength and toughness when used as a film or the like.

Claims (1)

50 to 98.5 mol% of diisopropyl fumarate residue units, 1 to 49.5 mol% of cinnamic acid ester residue units having an alkyl group having 1 to 6 carbon atoms, and 0.01 to 0.001 of bismaleimide residue units. A film using a diisopropyl fumarate-cinnamate-bismaleimide copolymer resin containing 5 mol% .