JP7024548B2 - Maleimide resin manufacturing method - Google Patents

Description

The present invention relates to a method for producing a maleimide resin.

Interlayer insulation materials used for printed wiring boards, electronic components, etc. are required to be able to meet the demands of mounting electronic components with lead-free solder and flame retardancy with halogen-free due to the growing environmental awareness in recent years. There is. Since lead-free solder has a higher operating temperature than conventional solder, the interlayer insulating material is required to have even higher heat resistance. Further, from the viewpoint of product safety and reliability, as the resin used for the interlayer insulating material, a resin having little or no volatile components and the like is desired.

Polyimide resin and maleimide resin are suitably used for printed wiring boards and the like as resins having excellent heat resistance (see Patent Documents 1 to 3). Therefore, as a resin used as an interlayer insulating material, a polyimide resin and a maleimide resin are being studied.

Generally, when synthesizing a polyimide resin and a maleimide resin, a dehydration ring closure reaction is involved, and heating at 160 ° C. or higher is required during the reaction. Therefore, a high boiling point solvent, N-methylpyrrolidone (NMP) or γ- An organic solvent having a boiling point of about 200 ° C. such as butyrolactone is used. On the other hand, there is also a report example in which a maleimide resin is synthesized using toluene having a boiling point of about 110 ° C. as a solvent (see Patent Document 3). However, the synthesis method using toluene requires a long reaction time of, for example, more than 10 hours, and also requires a large amount of a reaction catalyst and a dehydrating agent.

Japanese Unexamined Patent Publication No. 58-119093 Japanese Unexamined Patent Publication No. 63-06634 Special Table 2006-526014

Therefore, an object of the present invention is to provide a method for producing a maleimide resin, which can efficiently produce a maleimide resin in a short time even when a solvent having a relatively low boiling point such as toluene is used.

［式（２）及び（３）中、ｍ、ｎ、ｐ及びｑはそれぞれ、ｍ＋ｎ＝６～１７、ｐ＋ｑ＝８～１９となるように選ばれる１以上の整数を示し、破線で示した結合は、炭素－炭素単結合又は炭素－炭素二重結合を意味する。但し、破線で示した結合が炭素－炭素二重結合である場合、式（２）及び（３）は、炭素－炭素二重結合を構成する各炭素原子に結合する水素原子の数を、式（２）及び（３）に示した数から１つ減じた構造となる。］
［４］上記（Ｅ）無水マレイン酸又はその誘導体が、下記式（４）～（７）で表される化合物の少なくとも一種を含む、上記［１］～［３］のいずれかに記載のマレイミド樹脂の製造方法。

［式（５）～（７）中、Ｒ^２、Ｒ^３及びＲ^４は各々独立に、アルキル基、アリール基、アリールアルキル基又はハロゲン原子を示し、Ｒ^５はプロピレン基又はブチレン基を示す。］
［５］上記（Ｃ）酸触媒が、マレイン酸、フタル酸、ギ酸、メタンスルホン酸、ｐ－トルエンスルホン酸一水和物及びトリフルオロメタンスルホン酸からなる群より選択される少なくとも一種を含む、上記［１］～［４］のいずれかに記載のマレイミド樹脂の製造方法。
［６］上記（Ｃ）酸触媒の添加量が、上記（Ｂ）ジアミン１．０ｍｏｌに対し、０．３０ｍｏｌ以下である、上記［１］～［５］のいずれかに記載のマレイミド樹脂の製造方法。
［７］上記（Ｄ）有機溶媒が、沸点が１８０℃以下の有機溶媒から選ばれる１種又は２種以上を組み合わせた溶媒である、上記［１］～［６］のいずれかに記載のマレイミド樹脂の製造方法。 As a result of studying to solve the above-mentioned problems, the present inventors have found that the following problems can be solved by the present invention. That is, the present invention provides the following inventions.
[1] The first reaction step of reacting (A) tetracarboxylic acid dianhydride and (B) diamine in the presence of (C) an acid catalyst and (D) an organic solvent to obtain a polyimide resin, and the above. It has a second reaction step of further reacting (E) maleic anhydride or a derivative thereof with a polyimide resin to obtain a maleimide resin, and has at least a part of the time of the first reaction step and the second reaction step. (D) A method for producing a maleimide resin, wherein the reaction is carried out while refluxing at least a part of the organic solvent (D) under a pressure of 50 kPa or more in a gauge pressure of at least a part of the reaction step.
[2] The method for producing a maleimide resin according to the above [1], wherein the diamine (B) contains a substituted or unsubstituted aliphatic diamine.
[3] The method for producing a maleimide resin according to the above [1] or [2], wherein the (B) diamine contains a dimer diamine represented by the following general formulas (2) and / or (3).

[In equations (2) and (3), m, n, p and q represent one or more integers selected so that m + n = 6 to 17 and p + q = 8 to 19, respectively, and are combined as shown by a broken line. Means a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond shown by the broken line is a carbon-carbon double bond, the formulas (2) and (3) are the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond. The structure is one less than the numbers shown in (2) and (3). ]
[4] The maleimide according to any one of the above [1] to [3], wherein the above (E) maleic anhydride or a derivative thereof contains at least one of the compounds represented by the following formulas (4) to (7). Resin manufacturing method.

[In formulas (5) to (7), R ² , R ³ and R ⁴ independently represent an alkyl group, an aryl group, an arylalkyl group or a halogen atom, and R ⁵ represents a propylene group or a butylene group. ]
[5] The acid catalyst (C) comprises at least one selected from the group consisting of maleic acid, phthalic acid, formic acid, methanesulfonic acid, p-toluenesulfonic acid monohydrate and trifluoromethanesulfonic acid. The method for producing a maleimide resin according to any one of [1] to [4].
[6] Production of the maleimide resin according to any one of [1] to [5] above, wherein the amount of the acid catalyst added (C) is 0.30 mol or less with respect to 1.0 mol of the diamine (B). Method.
[7] The maleimide according to any one of the above [1] to [6], wherein the organic solvent (D) is a solvent selected from organic solvents having a boiling point of 180 ° C. or lower, or a combination of two or more. Resin manufacturing method.

According to the present invention, it is possible to provide a method for producing a maleimide resin, which can efficiently produce a maleimide resin in a short time even when a solvent having a relatively low boiling point such as toluene is used. Further, according to the production method of the present invention, the reaction can be allowed to proceed in a short time while reducing the amount of the acid catalyst added.

Hereinafter, the present invention will be described in detail according to the preferred embodiment thereof.

In the present specification, the numerical range indicated by using "-" indicates a range including the numerical values before and after "-" as the minimum value and the maximum value, respectively. Within the numerical range described stepwise herein, the upper or lower limit of the numerical range at one stage may be optionally combined with the upper or lower limit of the numerical range at another stage. In the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. "A or B" may include either A or B, and may include both. Unless otherwise specified, the materials exemplified in the present specification may be used alone or in combination of two or more.

In the method for producing a maleimide resin of the present embodiment, (A) tetracarboxylic acid dianhydride and (B) diamine are reacted in the presence of (C) an acid catalyst and (D) an organic solvent to obtain a polyimide resin. It has a first reaction step and a second reaction step of further reacting the polyimide resin with (E) maleic anhydride or a derivative thereof to obtain a maleimide resin, and at least a part of the first reaction step. And at least a part of the time of the second reaction step, the reaction is carried out under a pressure of 50 kPa or more while refluxing at least a part of the organic solvent (D). ..

According to the above production method, at least a part of the time of the first and second reaction steps is carried out under a specific pressure condition while refluxing the solvent, so that the boiling point of the organic solvent used is higher than the boiling point at normal pressure. Since the reaction can be carried out at a high temperature, the maleimide resin can be efficiently produced in a short time even when a solvent having a relatively low boiling point such as toluene is used. Further, for the above reason, according to the production method of the present embodiment, for example, the maleimide resin can be produced without using an organic solvent having a boiling point of about 200 ° C. or higher, so that the organic solvent can be easily removed. Therefore, it is possible to suppress the residual organic solvent in the obtained maleimide resin, the resin composition using the resin composition, the pressure-sensitive adhesive sheet and the printed wiring board using them. Further, according to the production method of the present embodiment, the reaction can proceed in a short time even with a small amount of acid catalyst. Hereinafter, each component and each step in the method for producing a maleimide resin of the present embodiment will be described in detail.

式（１）中、Ｒ^１は４価の有機基を示す。Ｒ^１は、置換又は非置換の脂肪族炭化水素基、置換又は非置換のヘテロ脂肪族炭化水素基、置換又は非置換の芳香族炭化水素基、或いは置換又は非置換のヘテロ芳香族炭化水素基を有する４価の有機基であってもよい。上記脂肪族炭化水素基は、脂環式炭化水素基であってもよい。４価の有機基は、炭素数４～３０の有機基であってもよい。Ｒ^１は、例えば、ベンゼン、ナフタレン、ペリレン、ビフェニル等の芳香族炭化水素（アリール）、ジフェニルエーテル、ジフェニルスルホン、ジフェニルプロパン、ジフェニルヘキサフルオロプロパン、ベンゾフェノン等の芳香族炭化水素基を有する化合物、ピロール、フラン、チオフェン、オキサゾール、チアゾール、ピリジン、プリミジン、キノリン、クマリン、インドール、ベンゾフラン、アクリジン、フェノキサジン、カルバゾール等のヘテロ芳香族炭化水素、ジピリジルジスルフィド等のヘテロ芳香族炭化水素基を有する化合物、ブタン、シクロブタン、シクロペンタン等の脂肪族炭化水素（アルカン）、ピペリジン、ピペラジン、モルホリン、ピロリジン等のヘテロ脂肪族炭化水素などの化合物から４個の水素原子を取り除いた基が挙げられる。芳香族炭化水素基を有する化合物は、芳香族炭化水素から４個の水素原子を取り除いた基であることが好ましい。Ｒ^１は、得られるマレイミド樹脂の耐熱性の向上及び入手しやすさの観点から、芳香族炭化水素から４個の水素原子を取り除いた基であることが好ましく、ベンゼン又はビフェニルから４個の水素原子を取り除いた基であることがより好ましい。 [(A) Tetracarboxylic dianhydride]
The (A) tetracarboxylic dianhydride used in this embodiment is, for example, a compound represented by the following general formula (1).

In formula (1), R ¹ represents a tetravalent organic group. ^R1 is a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted heteroaliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heteroaromatic hydrocarbon group. It may be a tetravalent organic group having. The aliphatic hydrocarbon group may be an alicyclic hydrocarbon group. The tetravalent organic group may be an organic group having 4 to 30 carbon atoms. R ¹ is, for example, an aromatic hydrocarbon (aryl) such as benzene, naphthalene, perylene, biphenyl, a compound having an aromatic hydrocarbon group such as diphenyl ether, diphenyl sulfone, diphenyl propane, diphenyl hexafluoropropane, benzophenone, pyrrole, and the like. Heteroaromatic hydrocarbons such as furan, thiophene, oxazole, thiazole, pyridine, primidine, quinoline, coumarin, indol, benzofuran, aclysine, phenoxazine, carbazole, compounds with heteroaromatic hydrocarbon groups such as dipyridyldisulfide, butane, Examples thereof include a group obtained by removing four hydrogen atoms from a compound such as an aliphatic hydrocarbon (alcan) such as cyclobutane and cyclopentane, and a heteroaliphatic hydrocarbon such as piperidine, piperazine, morpholine and pyrrolidine. The compound having an aromatic hydrocarbon group is preferably a group obtained by removing four hydrogen atoms from an aromatic hydrocarbon. From the viewpoint of improving the heat resistance of the obtained maleimide resin and making it easily available, R ¹ is preferably a group obtained by removing 4 hydrogen atoms from an aromatic hydrocarbon, and 4 hydrogens from benzene or biphenyl. More preferably, it is a group from which atoms have been removed.

(A) Specific examples of the tetracarboxylic acid dianhydride include, for example, pyromellitic acid dianhydride, 4,4'-oxydiphthalic acid anhydride, 3,3', 4,4'-benzophenone tetracarboxylic acid dianhydride. , 3,3', 4,4'-diphenyl ether tetracarboxylic acid dianhydride, 3,3', 4,4'-diphenyl sulfone tetracarboxylic acid dianhydride, 1,2,3,4-benzenetetracarboxylic Acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 3,3', 4,4'-biphenyltetracarboxylic Acid dianhydride, 2,2', 3,3'-biphenyltetracarboxylic acid dianhydride, 2,3,3', 4'-biphenyltetracarboxylic acid dianhydride, 2,3,3', 4' -Benzophenone tetracarboxylic acid dianhydride, 2,3,3', 4'-diphenyl ether tetracarboxylic acid dianhydride, 2,3,3', 4'-diphenylsulfone tetracarboxylic acid dianhydride, 2,2- Bis (3,3', 4,4'-tetracarboxyphenyl) Tetrafluoropropane dianhydride, 2,2'-bis (3,4-dicarboxyphenoxyphenyl) sulfonate dianhydride, 2,2-bis ( 2,3-Dicarboxyphenyl) propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, cyclopentanetetracarboxylic acid dianhydride, butane-1,2,3,4 -Tetracarboxylic acid, 2,3,5-tricarboxycyclopentylacetichydride, 4,4'-[Propane-2,2-diylbis (1,4-phenyleneoxy)] diphthalic anhydride, 4,4'. -(Hexafluoroisopropylidene) diphthalic anhydride and the like can be mentioned. One of these may be used alone, or two or more thereof may be used in combination. Among these, the tetracarboxylic dianhydride (A) preferably contains pyromellitic dianhydride from the viewpoint of increasing the heat resistance of the obtained maleimide resin.

[(B) Diamine]
The (B) diamine used in the present embodiment is not particularly limited, and is, for example, α, ω-bis (2-aminoethyl) polydimethylsiloxane, α, ω-bis (3-aminopropyl) polydimethylsiloxane, α, ω-bis (4-aminobutyl) polydimethylsiloxane, α, ω-bis (5-aminopentyl) polydimethylsiloxane, α, ω-bis [3- (2-aminophenyl) propyl] polydimethylsiloxane, α, Diaminopolysiloxanes such as ω-bis [3- (4-aminophenyl) propyl] polydimethylsiloxane; 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-Aminophenoxy) Phenyl] Bisaminophenoxyphenyl propanes such as propane; diaminodiphenyl ethers such as 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether; p-phenylene Phenylene diamines such as diamine and m-phenylenediamine; diaminodiphenyl sulfides such as 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide; 3,3'- Diaminodiphenyl sulfones such as diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone; 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,4'-diamino Diaminobenzophenones such as benzophenone; diaminodiphenylmethanes such as 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane; 2,2-di (3-aminophenyl) propane, 2, , 2-Di (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane and other diaminophenyl propanes; 2,2-di (3-aminophenyl) -1 , 1,1,3,3,3-hexafluoropropane, 2,2-di (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2- (3-aminophenyl) )-2- (4-Aminophenyl) -1,1,1,3,3,3-Diaminophenyl hexafluoropropanes such as hexafluoropropane; 1,1-di (3-aminophenyl) -1-phenyl Etan, 1,1-di (4-aminophenyl) -1 -Diaminophenylphenylethanes such as phenylethane, 1- (3-aminophenyl) -1- (4-aminophenyl) -1-phenylethane; 1,3-bis (3-aminophenoxy) benzene, 1,3 -Bisaminophenoxybenzenes such as bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene; 1,3-bis (3) -Bisaminobenzoylbenzene such as aminobenzoyl) benzene, 1,3-bis (4-aminobenzoyl) benzene, 1,4-bis (3-aminobenzoyl) benzene, and 1,4-bis (4-aminobenzoyl) benzene. Class: 1,3-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,3-bis (4-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (3-amino-) Bisaminodimethylbenzenes such as α, α-dimethylbenzyl) benzene and 1,4-bis (4-amino-α, α-dimethylbenzyl) benzene; 1,3-bis (3-amino-α, α-ditri) Fluoromethylbenzyl) benzene, 1,3-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1, Bisaminoditrifluoromethylbenzylbenzenes such as 4-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene; 2,6-bis (3-aminophenoxy) benzonitrile, 2,6-bis (3) Aminophenoxybiphenyls such as -aminophenoxy) pyridine, 4,4'-bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl; bis [4- (3-aminophenoxy) Aminophenoxyphenyl ketones such as phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone; bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl ] Aminophenoxyphenyl sulfides such as sulfide; Aminophenoxyphenyl sulfone such as bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone; Aminophenoxyphenyl A such as 3-aminophenoxy) phenyl] ether and bis [4- (4-aminophenoxy) phenyl] ether. Ethers; 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3-3 Aminophenoxyphenyl propanes such as hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane; and others 1,3- Bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-Aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4-bis [4- (3-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4-bis [4- (4) -Aminophenoxy) -α, α-dimethylbenzyl] benzene, 4,4'-bis [4- (4-aminophenoxy) benzoyl] diphenyl ether, 4,4'-bis [4- (4-amino-α, α) -Dimethylbenzyl) phenoxy] benzophenone, 4,4'-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] diphenyl sulfone, 4,4'-bis [4- (4-aminophenoxy) phenoxy) ] Diphenyl sulfone, 3,3'-diamino-4,4'-diphenoxybenzophenone, 3,3'-diamino-4,4'-dibiphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 3, 3'-Diamino-4-biphenoxybenzophenone, 6,6'-bis (3-aminophenoxy) -3,3,3,'3,'-tetramethyl-1,1'-spirobiindan, 6,6'- Bis (4-aminophenoxy) -3,3,3, '3,'-tetramethyl-1,1'-spirobiindan, 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1,3-bis (4-Aminobutyl) tetramethyldisiloxane, bis (aminomethyl) ether, bis (2-aminoethyl) ether, bis (3-aminopropyl) ether, bis (2-aminomethoxy) ethyl] ether, bis [2 -(2-Aminoethoxy) ethyl] ether, bis [2- (3-aminoprotoxy) ) Ethyl] ether, 1,2-bis (aminomethoxy) ethane, 1,2-bis (2-aminoethoxy) ethane, 1,2-bis [2- (aminomethoxy) ethoxy] ethane, 1,2-bis [2- (2-Aminoethoxy) ethoxy] ethane, ethylene glycol-rubis (3-aminopropyl) ether, diethylene glycol-rubis (3-aminopropyl) ether, triethylene glycol-rubis (3-aminopropyl) ether, ethylenediamine , 1,3-Diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1, , 10-Diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1,2-di (2-amino) Ethyl) cyclohexane, 1,3-di (2-aminoethyl) cyclohexane, 1,4-di (2-aminoethyl) cyclohexane, bis (4-aminocyclohexyl) methane, 2,6-bis (aminomethyl) Examples thereof include bicyclo [2.2.1] heptan, 2,5-bis (aminomethyl) bicyclo [2.2.1] heptan, 1,3-bis (aminomethyl) cyclohexane, and dimerdiamine. One of these may be used alone, or two or more thereof may be used in combination. Among these, the diamine (B) preferably contains a substituted or unsubstituted aliphatic diamine, and particularly preferably contains a dimer diamine, from the viewpoint of reducing the elastic modulus of the obtained maleimide resin.

Dimerdiamine is a compound derived from dimer acid, which is a dimer of unsaturated fatty acids such as oleic acid. In the present embodiment, known diamine diamines can be used without particular limitation, but for example, dimer diamines represented by the following general formulas (2) and / or general formulas (3) are preferable.

In equations (2) and (3), m, n, p and q represent integers of 1 or more selected so that m + n = 6 to 17 and p + q = 8 to 19, respectively, and are integers of 1 to 12, respectively. There may be. Further, in the formulas (2) and (3), the bond shown by a broken line means a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond shown by the broken line is a carbon-carbon double bond, the formulas (2) and (3) are the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond. The structure is one less than the numbers shown in (2) and (3).

As the dimer diamine, the organic solvent solubility of the obtained maleimide resin and the initial adhesiveness, heat resistant adhesiveness, low tackiness, and low tackiness of the adhesive composition when the maleimide resin is used as the material of the adhesive composition. From the viewpoint of improving the adhesive residue property, the compound represented by the above general formula (3) is preferable, and the compound represented by the following formula (3-1) is particularly preferable.

Examples of commercially available diamine diamines include PRIAMINE 1075 and PRIAMINE 1074 (both manufactured by Croder Japan Co., Ltd.).

[Amount of (A) tetracarboxylic dianhydride and (B) diamine]
In the method for producing a maleimide resin according to the present embodiment, the molecular weight of the finally obtained maleimide resin can be controlled by the blending ratio of (A) tetracarboxylic dianhydride and (B) diamine. The ratio thereof is preferably 0.30 to 0.95 mol of (A) tetracarboxylic dianhydride with respect to 1.0 mol of (B) diamine, and more preferably 0.40 to 0.90 mol. It is preferably 0.55 to 0.80 mol, and more preferably 0.55 to 0.80 mol. By setting the ratio of (A) tetracarboxylic dianhydride to 0.95 mol or less, the number of maleimide groups that can be introduced by reaction can be increased, and a maleimide resin that is easily cured when irradiated with active energy rays can be obtained. Tend. Further, by setting the ratio of (A) tetracarboxylic dianhydride to 0.30 mol or more, the low molecular weight component can be reduced, and a maleimide resin having good heat resistance tends to be easily obtained.

[(C) Acid catalyst]
The acid catalyst (C) used in the present embodiment is not particularly limited, but has an acid dissociation constant (pKa) of 5 or less from the viewpoint of suppressing by-products and shortening the reaction time. Is preferable. Examples of the acid catalyst (C) include maleic acid, phthalic acid, formic acid, acetic acid, methanesulfonic acid, p-toluenesulfonic acid monohydrate, trifluoromethanesulfonic acid and the like. These can be used alone or in combination of two or more. Among these, methanesulfonic acid, p-toluenesulfonic acid monohydrate, and trifluoromethanesulfonic acid are particularly preferable from the viewpoint of pKa.

In the production method according to the present embodiment, the amount of the (C) acid catalyst used is preferably 0.001 to 0.30 mol, more preferably 0.02 to 0.20 mol, based on 1.0 mol of the (B) diamine. When the amount of the (C) acid catalyst used is 0.30 mol or less, the obtained maleimide resin can be easily purified, and the possibility that the (C) acid catalyst remains and the heat resistance is lowered can be reduced. Further, according to the production method of the present embodiment, it is possible to produce a maleimide resin having a high molecular weight in a short time even if the amount of the (C) acid catalyst used is small. On the other hand, when the amount of the acid catalyst (C) used is 0.001 mol or more, by-products can be suppressed and a maleimide resin having good heat resistance tends to be obtained.

[(D) Organic solvent]
The organic solvent (D) used in the present embodiment is not particularly limited as long as it contains a solvent in which the synthesized maleimide resin is dissolved, and for example, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, methylene, tetralin, and ethylene. Glycomonomethyl ether, N, N'-dimethylformamide, dimethylacetamide, N-methylcaprolactum, methyltriglime, methyldiglyme, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, benzyl alcohol, cresol, propylene glycol monomethyl Examples thereof include ether, methylisobutylcarbinol, 1-propanol-2-propanol, cyclopentanone, cyclohexanone, methylcyclohexane, N-methylpyrrolidone, γ-butyrolactone and the like. These can be used alone or in combination of two or more.

The organic solvent (D) may contain alcohols in order to esterify and dissolve (A) the tetracarboxylic dianhydride in the imidization reaction in the first reaction step. As the alcohols, known alcohols can be used without particular limitation, and examples thereof include methanol, ethanol, 1-propanol, isopropanol, 1-butanol, benzyl alcohol and the like. These can be used alone or in combination of two or more. Among these, methanol and ethanol are particularly preferable from the viewpoint of easiness of desorption when the imide ring is closed. Here, the ease of hydrolysis of the ester generally depends on the carbon number (boiling point) of the alcohol, and the lower the boiling point of the alcohol, the higher the desorption ability and the easier it is to desorb when the imide is closed. Therefore, as alcohols, methanol and ethanol are preferable. It should be noted that solvents having a low boiling point such as methanol and ethanol have been difficult to use for the synthesis of polyimide resin, but according to the production method of the present embodiment, the reaction is carried out under specific pressure conditions. It became possible to use them. By using these alcohols, the dehydration ring closure reaction in the first reaction step can be further promoted, the reaction can be uniformly carried out, and a maleimide resin having a high molecular weight and a low dispersity can be efficiently produced. Can be done.

Further, the alcohols are preferably used in combination with a non-polar solvent such as toluene, xylene and mesitylene. In this case, the tetracarboxylic dianhydride (A) esterified with alcohols can be easily dissolved in a non-polar solvent. When a non-polar solvent is used alone without using alcohols, (A) tetracarboxylic dianhydride may not be sufficiently dissolved in (D) an organic solvent and the reaction may become non-uniform. , The degree of dispersion of the molecular weight of the obtained maleimide resin tends to be large, side reactions tend to occur easily, and raw materials tend to remain.

When alcohols are used, the amount used is not particularly limited, but from the viewpoint of further obtaining the effect of promoting the dehydration ring closure reaction in the first reaction step and homogenizing the reaction, (A) tetracarboxylic dianhydride is used. It is preferable to use 2 mol or more with respect to 1 mol of the product, and it is more preferable to use 2 to 8 mol. When alcohols are used in combination with a non-polar solvent such as toluene, the amount of alcohols used is preferably 0.1 to 40% by mass based on the total amount of (D) organic solvent from the same viewpoint as above. More preferably, it is 5 to 25% by mass.

The organic solvent (D) is not particularly limited, but is preferably one or a combination of two or more selected from organic solvents having a boiling point of 180 ° C. or lower. The boiling point of the organic solvent used is more preferably 50 to 180 ° C, further preferably 55 to 160 ° C, and particularly preferably 60 to 150 ° C. When the boiling point exceeds 180 ° C., high temperature and long-term heating are required to remove the solvent, so that the heating may cause deterioration of the maleimide resin. Further, if the removal of the solvent is insufficient, a high boiling point solvent may be mixed in the resin composition using the maleimide resin, which may lower the reliability of the product using this resin composition. Further, when the boiling point is less than 50 ° C., a high pressure is required when applying pressure to raise the boiling point, which is dangerous in manufacturing.

In the production method according to the present embodiment, the amount of the organic solvent (D) used is not particularly limited as long as it dissolves the synthesized maleimide resin, but from the viewpoint of optimizing the viscosity and promoting the dehydration ring closure reaction, the amount is not particularly limited. The total concentration of the components (A) to (C) in the reaction solution in which the components (A) to (D) are mixed is preferably an amount of 10 to 70% by mass, preferably 30 to 50% by mass. Is more preferable.

[(E) Maleic anhydride or its derivative]
The maleic anhydride (E) maleic anhydride or a derivative thereof used in the present embodiment is not particularly limited, and one or more selected from the unsubstituted, mono-substituted and di-substituted maleic anhydrides of maleic anhydride is used. Can be used in combination. Examples of the unsubstituted body include maleic anhydride. Examples of the mono-substituted product include citraconic acid anhydride, phenylmaleic anhydride, 3-bromofuran-2,5-dione, cis-aconitic acid anhydride, and 3- (4-methoxyphenyl) furan-2,5-. Examples thereof include dione, 3-phenylfuran-2,5-dione, 3- (4-chlorophenyl) furan-2,5-dione and the like. Examples of the disubstituted product include 1-cyclohexene-1,2-dicarboxylic acid anhydride, 2,3-diphenylmaleic acid anhydride, 1-cyclopentene-1,2-dicarboxylic acid anhydride, and 2,3-dimethylmaleine. Acid Anhydride, 2,5-Dihydro-4-methyl-2,5-dioxo-3-franpropionic Acid, 3,4-dichlorofuran-2,5-dione, 3,4-dibromofuran-2,5- Dione, 3,4-dibenzylfuran-2,5-dione and the like can be mentioned. These can be used alone or in combination of two or more. According to the literature (Toagosei Group Annual Research Report, TREND 2009, No. 12, pp. 31-33), the maleimide resin synthesized using the unsubstituted form of maleic anhydride can be obtained only by irradiation with active energy rays. It can be cured even with heat. On the other hand, the maleimide resin synthesized by using the mono- or di-substituted maleic anhydride is cured by irradiation with active energy rays, but is difficult to be cured by heat. In view of these, maleic anhydride or a derivative thereof is appropriately selected.

式（５）～（７）中、Ｒ^２、Ｒ^３及びＲ^４は各々独立に、アルキル基、アリール基、アリールアルキル基又はハロゲン原子を示し、好ましくは炭素数１～４のアルキル基、炭素数６～１５のアリール基、炭素数６～１８のアリールアルキル基又はハロゲン原子を示す。また、Ｒ^５はプロピレン基又はブチレン基を示す。 (E) Maleic anhydride or a derivative thereof may contain at least one of the compounds represented by the following formulas (4) to (7) from the viewpoint of reacting with a compound having a functional group such as an epoxy group or an acrylic group. preferable.

In formulas (5) to (7), R ² , R ³ and R ⁴ independently represent an alkyl group, an aryl group, an arylalkyl group or a halogen atom, preferably an alkyl group having 1 to 4 carbon atoms and carbon. An aryl group having 6 to 15 carbon atoms, an arylalkyl group having 6 to 18 carbon atoms or a halogen atom is shown. Further, R ⁵ represents a propylene group or a butylene group.

(E) Maleic anhydride or a derivative thereof is added in order to react with the polyimide resin in the second reaction step after synthesizing the polyimide resin as an intermediate in the first reaction step. (E) The amount of maleic anhydride or a derivative thereof added is preferably 2.0 to 4.0 mol, more preferably 2.2 to 3.0 mol with respect to 1 mol of the polyimide resin. When the addition amount is 2.0 mol or more, side reactions can be suppressed and the heat resistance of the obtained maleimide resin tends to be improved. When the addition amount is 4.0 mol or less, the maleimide resin can be easily purified. Tend.

[Manufacturing method of maleimide resin]
In the method for producing a maleimide resin according to the present embodiment, first, (A) tetracarboxylic dianhydride and (B) diamine are reacted in the presence of (C) acid catalyst and (D) organic solvent to form polyimide. Obtain a resin (first reaction step). In the first reaction step, first, the ammonium salt is reacted at a temperature of usually about 60 to 140 ° C., preferably 80 to 120 ° C. for usually about 0.1 to 2 hours, preferably about 0.1 to 1 hour to obtain an ammonium salt. To generate. This reaction is carried out without the addition of the (C) acid catalyst. Then, the acid catalyst (C) is added, and the ammonium salt is subjected to a heavy addition reaction at a temperature of about 80 to 200 ° C., preferably 100 to 150 ° C. for about 0.2 to 2 hours, preferably about 0.5 to 1 hour. To produce a polyamic acid. Further, the polyimide of the intermediate is formed by subjecting the polyamic acid to an imidization reaction, that is, a dehydration ring closure reaction, at a temperature of about 80 to 250 ° C., preferably 100 to 200 ° C. for about 0.5 to 15 hours, preferably 1 to 5 hours. A resin is obtained.

Further, (E) maleic anhydride or a derivative thereof is added to the polyimide resin obtained in the first reaction step, and the temperature is usually about 80 to 200 ° C, preferably 100 to 180 ° C, more preferably 120 to 170 ° C. The desired maleimide resin is obtained by subjecting it to a maleimide formation reaction, that is, a dehydration ring closure reaction at a temperature of about 0.5 to 15 hours, preferably 1 to 5 hours (second reaction step).

In the production method of the present embodiment, the first and second reaction steps are carried out under pressure with a gauge pressure of 50 kPa or more while refluxing at least a part of the (D) organic solvent. The pressurization and refluxing need not always be performed during the reaction time of the first and second reaction steps, and may be performed at least a part of the reaction time. In addition, pressurization and / or reflux may not be performed at the time of material charging and at the reaction preparation stage such as during temperature rise. By performing the first and second reaction steps including the above pressurization and reflux, the reaction temperature can be set to a temperature higher than the boiling point of the organic solvent (D) at room temperature, and the reaction time can be shortened. can. Further, it becomes possible to use an organic solvent having a low boiling point. By using an organic solvent having a low boiling point, it becomes easy to dry and remove the solvent from the obtained maleimide resin, and the organic solvent is less likely to remain, so that the reliability of the product is easily improved. From the viewpoint of more sufficiently obtaining the above effects, the pressure in the first and second reaction steps is preferably 100 kPa or more, more preferably 150 kPa or more, still more preferably 200 kPa or more in gauge pressure. .. The upper limit of the pressure is not particularly limited, but may be 400 kPa or less, or 350 kPa or less, from the viewpoint of the pressure resistance of the synthesizer.

In the first and second reaction steps, the gauge pressure does not have to be constant and may vary. Further, the gauge pressure during the reaction does not have to be 50 kPa or more at all times, and may temporarily fall below 50 kPa. For example, in the first and second reaction steps, the gauge pressure is preferably 50 kPa or more at 50% or more of the total reaction time of each step, more preferably 50 kPa or more at 80% or more, and more preferably 100. It is most preferably 50 kPa or more in%.

The first and second reaction steps can be carried out in a pressure resistant container. Pressurization can be performed by introducing an inert gas such as nitrogen gas into a pressure-resistant container. Further, in the first and second reaction steps, the reaction is carried out while refluxing the solvent using a cooler or the like. By carrying out the reaction while refluxing the solvent, the reaction can be stably carried out at a high temperature for a long time, and the reaction time can be shortened. Reflux in a pressure resistant container can be performed by a synthetic facility with circulating equipment equipped with a cooling tube and a separation tank.

Further, various known reaction catalysts and dehydrating agents may be used in the first and second reaction steps. Examples of the reaction catalyst include tertiary amines such as triethylamine, tripropylamine, tributylamine and pyridine. Examples of the dehydrating agent include acetic anhydride, propionic anhydride, carbodiimide, magnesium sulfate, zinc chloride and the like.

The production method of the present embodiment may include a water washing step of washing and purifying the obtained maleimide resin after the second reaction step. Washing with water is performed by adding the obtained maleimide resin to water together with an organic solvent and stirring the mixture, separating the mixed solution after stirring into an aqueous layer and an oil layer (organic layer), and removing the aqueous layer. be able to. This series of operations may be repeated two or more times. Further, the washing with water may be performed at a liquid temperature of 50 to 100 ° C. By performing the washing step with water, ionic impurities can be removed. The recovered oil layer can be heated to remove water.

[Maleimide resin]
By the production method of this embodiment, for example, a maleimide resin represented by the following general formula (8) can be produced. The maleimide resin represented by the general formula (8) is an imide-extended bismaleimide resin, and comprises two maleimide groups in the molecule and a divalent group having at least two imide bonds. According to the production method of the present embodiment, the maleimide resin having such a structure can be efficiently produced in a short time.

式（８）中、Ｒ^１は式（１）中のＲ^１と同義である。Ｒ^６は各々独立に置換又は非置換の脂肪族炭化水素基、置換又は非置換のヘテロ脂肪族炭化水素基、置換又は非置換の芳香族炭化水素基、或いは置換又は非置換のヘテロ芳香族炭化水素基を有する２価の有機基を示す。ここで、２価の有機基は、炭素数４～１００の有機基であってもよく、炭素数４～６０の有機基であってもよい。なお、Ｒ^６は（Ｂ）ジアミンの残基である。また、ｎは０～１００の整数を示す。ｎは、１～３０の整数であってもよい。

In equation (8), R ¹ is synonymous with R ¹ in equation (1). R ⁶ is an independently substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted heteroaliphatic hydrocarbon group, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted heteroaromatic hydrocarbon. Shows a divalent organic group having a hydrogen group. Here, the divalent organic group may be an organic group having 4 to 100 carbon atoms or an organic group having 4 to 60 carbon atoms. R ⁶ is a residue of (B) diamine. Further, n indicates an integer from 0 to 100. n may be an integer of 1 to 30.

The molecular weight of the maleimide resin is preferably 2000 to 40,000, more preferably 7,000 to 25,000 in terms of weight average molecular weight. If the weight average molecular weight is less than 2000, the number of low molecular weight components may increase and the heat resistance may decrease, while if it exceeds 40,000, the viscosity of the resin may increase and the coatability may decrease.

The maleimide resin can be cured by heating and / or active energy rays.

To cure the maleimide resin by heating, it is usually heated at a temperature of about 150 to 250 ° C., preferably 180 to 220 ° C. for about 0.1 to 3 hours, preferably 0.1 to 1.5 hours, and then cured. Let me.

When the maleimide resin is cured by an active energy ray, examples of the active energy ray include visible light, ultraviolet rays, X-rays and electron beams, and it is preferable to use ultraviolet rays because an inexpensive device can be used. Examples of the light source when ultraviolet rays are used include ultra-high pressure, high pressure, medium pressure or low pressure mercury lamps, metal halide lamps, xenon lamps, electrodeless discharge lamps, carbon arc lamps and the like. The activation energy ray may be irradiated for a few seconds to a few minutes.

[Resin composition]
The maleimide resin can be easily cured by the active energy ray without adding a photopolymerization initiator, but a photopolymerization initiator can be added as needed to prepare a resin composition.

When a photopolymerization initiator is blended, the photopolymerization initiator includes benzoin and its alkyl ethers, acetophenones, anthraquinones, thioxanthones, ketals, benzophenones, xanthones, acylphosphine oxides, and α-diketone. Kind and the like. These can be used individually by 1 type or in combination of 2 or more types. The blending ratio thereof is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the maleimide resin.

In addition, a photosensitizer can also be used in combination to improve the sensitivity of the active energy rays.

Examples of the photosensitizer include benzoic acid-based and amine-based photosensitizers. These can be used individually by 1 type or in combination of 2 or more types. The blending ratio thereof is preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the maleimide resin.

As the photopolymerization initiator, benzophenones and thioxanthones are preferable because they have a high effect of improving the curing rate of the resin composition.

In addition to the maleimide resin, if necessary, flame retardant, inorganic filler, curing agent, dehydrating agent, plasticizer, weather resistant agent, antioxidant, heat stabilizer, lubricant, antistatic agent, whitening agent, etc. Additives such as a colorant, a conductive agent, a mold release agent, a surface treatment agent, a polymerization inhibitor, and a viscosity modifier may be blended to form a resin composition.

[Adhesive sheet]
The maleimide resin or the resin composition containing the maleimide resin can be used for various adhesives and adhesives, and can also be used in the form of an adhesive sheet.

The pressure-sensitive adhesive sheet can be produced by applying a maleimide resin or a resin composition containing a maleimide resin to a sheet substrate and drying it. The maleimide resin or the resin composition containing the maleimide resin applied to the sheet substrate may be cured by heating and / or active energy rays.

Examples of the material of the sheet base material include metal, plastic, glass, ceramics, wood, paper, printing paper and fibers. Examples of the metal include aluminum, iron and copper. Examples of the plastic include vinyl chloride polymer, acrylate polymer, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polyimide, acrylonitrile butadiene styrene copolymer, polyethylene and polypropylene.

Examples of the coating method of the maleimide resin or the resin composition containing the maleimide resin include roll coating, gravure printing, screen printing, die coating, knife coating and the like.

The amount of the maleimide resin or the resin composition containing the maleimide resin applied to the sheet substrate may be appropriately selected depending on the intended use, but the preferable amount of application is 5 to 200 g / m ² , more preferably. It is 10 to 100 g / m ² . If the coating amount is less than 5 g / m ² , the adhesive strength may be insufficient, and if it exceeds 200 g / m ² , the active energy rays may not reach the deep part and the desired performance may not be obtained. be.

The pressure-sensitive adhesive sheet formed by using a maleimide resin or a resin composition containing a maleimide resin can be used for various purposes such as a pressure-sensitive adhesive and an adhesive. In particular, since the maleimide resin obtained by the production method of the present embodiment has excellent heat resistance, the pressure-sensitive adhesive sheet is particularly useful for applications requiring heat resistance, and is used, for example, for printed wiring boards and electronic parts. It is useful as an interlayer insulating material.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. In the following, the method for measuring the physical properties of the maleimide resin and the reaction time in the manufacturing process are as follows.

[Molecular weight]
The molecular weight of the maleimide resin was measured by GPC (gel permeation chromatography). A sample in which a maleimide resin was dissolved in tetrahydrofuran (THF) to a concentration of 3% by mass was mixed with a column heated to 30 ° C. (GL-R420 (manufactured by Hitachi High-Tech Fielding Corporation) x 1, GL-R430 (GL-R430). 50 μL was injected into GL-R440 (manufactured by Hitachi High-Tech Fielding Co., Ltd.) x 1 and GL-R440 (manufactured by Hitachi High-Tech Fielding Co., Ltd.) x 1), and measurement was performed under the condition of a flow rate of 1.6 mL / min using THF as a developing solvent. rice field. An L-3350 RI detector (manufactured by Hitachi, Ltd.) was used as the detector, and a number average molecular weight (Mn) was obtained from the elution time using a molecular weight / elution time curve prepared using standard polystyrene (manufactured by Tosoh Corporation). ) And the weight average molecular weight (Mw) were converted.

[Reaction time of imidization reaction and maleimided reaction]
In this example, the reaction time of the imidization reaction (first reaction step) and the maleimided reaction (second reaction step) in producing the maleimide resin is the total amount of water and methanol generated during the reaction. However, the time when it became 95% by mass or more of the theoretical amount is shown. The total amount of water and methanol generated during the reaction is measured by extracting the liquid collected in the separation tank into an Erlenmeyer flask or the like and measuring the mass with a balance.

[Manufacturing method of maleimide resin]
(Example 1)
A 2L pressure-resistant SUS container (manufactured by Todoroki Sangyo Co., Ltd.) equipped with a cooling pipe, a separation tank, a nitrogen introduction pipe, a thermocouple, and a stirrer, and equipped with equipment capable of carrying out the reaction under pressure while refluxing the solvent. 111 parts by mass of pyromellitic acid dianhydride (manufactured by Daicel Co., Ltd.), 907 parts by mass of toluene (manufactured by Wako Pure Chemical Industries, Ltd.), and 200 parts by mass of methanol (manufactured by Daishin Chemical Industries, Ltd.) were added thereto. Next, nitrogen gas was introduced into the container and pressurized to a gauge pressure of 250 kPa, then the temperature was raised to 80 ° C. and the temperature was kept for 0.5 hours. Subsequently, 368 parts by mass of dimer diamine (trade name "PRIAMINE 1075", manufactured by Croder Japan Co., Ltd.) was added dropwise at a dropping rate of 12.3 g / min. After the dropping, the mixture was kept warm at 80 ° C. for 0.5 hours, and then 6.5 parts by mass of methanesulfonic acid was added. Then, a dehydration ring closure reaction was carried out at the reflux temperature and reaction time shown in Table 1 to remove water and methanol in the reaction solution to obtain an intermediate polyimide resin (first reaction step). Subsequently, the obtained polyimide resin was cooled to 135 ° C., 50 parts by mass of maleic anhydride (manufactured by Mitsui Kagaku Co., Ltd.) was added, and a dehydration ring closure reaction was further carried out at the reflux temperature and reaction time shown in Table 1 to react. The water in the liquid was removed to obtain an imide-extended maleimide resin (bismaleimide resin) (second reaction step). The first and second reaction steps were carried out while controlling the gauge pressure in the container to 250 ± 10 kPa and stirring the reaction solution at a rotation speed of 300 rpm.

The obtained maleimide resin was purified by the following method. That is, 1000 parts by mass of pure water was put into a 2 L glass container equipped with a cooling pipe, a separation tank, a nitrogen introduction pipe, a thermocouple, and a stirrer, and the temperature was raised to 85 ° C. After the temperature was raised, 500 parts by mass of a toluene solution of maleimide resin (concentration 35% by mass) was added to pure water being stirred at a rotation speed of 300 rpm, and the temperature was kept at 85 ° C. for 0.5 hours. After keeping the heat, the stirrer was stopped and the mixture was allowed to stand for 1 hour to separate the aqueous layer and the organic layer, and only the organic layer was recovered. The above operation was performed twice to purify the maleimide resin.

The purified maleimide resin was placed in a 1 L glass container equipped with a cooling tube, a separation tank, a nitrogen introduction tube, a thermocouple, and a stirrer, heated to 88 to 93 ° C., and then the water in the resin was removed. The temperature was raised to 110 to 120 ° C., and a part of toluene was removed to obtain a maleimide resin having a concentration of 60% by mass.

(Examples 2 to 3)
Maleimide resins were obtained in the same manner as in Example 1 except that the gauge pressure, reflux temperature and reaction time were changed as shown in Table 1 in the first and second reaction steps.

(Example 4)
Pyromellitic acid dianhydride was changed to 4,4'-oxydiphthalic anhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd.), and 4,4'-oxydiphthalic anhydride was changed to 158 parts by mass and toluene was changed to 994 parts by mass. A maleimide resin was obtained in the same manner as in Example 1 except for the above.

(Example 5)
Dimer diamine was changed to 2,2-bis [4- (4-aminophenoxy) phenyl] propane (manufactured by Tokyo Kasei Kogyo Co., Ltd.), and toluene was changed to cyclohexanone (manufactured by Wako Pure Chemical Industries, Ltd.). [4- (4-Aminophenoxy) phenyl] Propane was 279 parts by mass and cyclohexanone was 740 parts by mass, and the gauge pressure, reflux temperature and reaction time in the first and second reaction steps were changed as shown in Table 1. A maleimide resin was obtained in the same manner as in Example 1 except for the above.

(Example 6)
Same as Example 1 except that methanesulfonic acid was changed to p-toluenesulfonic acid monohydrate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) and p-toluenesulfonic acid monohydrate was 11.7 parts by mass. Then, a maleimide resin was obtained.

(Example 7)
The maleimide resin was prepared in the same manner as in Example 1 except that the solvent was changed from toluene to xylene and the gauge pressure, reflux temperature and reaction time were changed as shown in Table 2 in the first and second reaction steps. Obtained.

(Example 8)
The maleimide resin was prepared in the same manner as in Example 1 except that the solvent was changed from toluene to xylene and the gauge pressure, reflux temperature and reaction time were changed as shown in Table 2 in the first and second reaction steps. Obtained.

(Comparative Example 1)
The maleimide resin was obtained in the same manner as in Example 1 except that the first and second reaction steps were carried out at normal pressure without pressurization and the reflux temperature and reaction time were changed as shown in Table 2. rice field.

(Comparative Example 2)
Maleimide resins were obtained in the same manner as in Example 1 except that the gauge pressure, reflux temperature and reaction time were changed as shown in Table 2 in the first and second reaction steps.

As is clear from the results shown in Tables 1 and 2, according to the production methods of Examples 1 to 8, the production methods of Comparative Examples 1 and 2 in which the reaction is carried out under normal pressure or a pressure of less than 50 kPa gauge pressure are used. By comparison, it was confirmed that the maleimide resin having the same molecular weight as Comparative Examples 1 and 2 can be produced in a shorter time.

Claims (7)

The first reaction step of reacting (A) tetracarboxylic dianhydride and (B) diamine in the presence of (C) an acid catalyst and (D) an organic solvent to obtain a polyimide resin.
It has a second reaction step of further reacting the polyimide resin with (E) maleic anhydride or a derivative thereof to obtain a maleimide resin.
At least a part of the organic solvent (D) under pressure having a gauge pressure of 50 kPa or more during at least a part of the time of the first reaction step and at least a part of the time of the second reaction step. A method for producing a maleimide resin, in which the reaction is carried out while refluxing. The method for producing a maleimide resin according to claim 1, wherein the (B) diamine contains a substituted or unsubstituted aliphatic diamine. The method for producing a maleimide resin according to claim 1 or 2, wherein the (B) diamine contains a dimer diamine represented by the following general formulas (2) and / or (3).

[In equations (2) and (3), m, n, p and q represent one or more integers selected so that m + n = 6 to 17 and p + q = 8 to 19, respectively, and the bond shown by a broken line. Means a carbon-carbon single bond or a carbon-carbon double bond. However, when the bond shown by the broken line is a carbon-carbon double bond, the formulas (2) and (3) are the number of hydrogen atoms bonded to each carbon atom constituting the carbon-carbon double bond. The structure is one less than the numbers shown in (2) and (3). ] The method for producing a maleimide resin according to any one of claims 1 to 3, wherein the maleic anhydride or a derivative thereof contains at least one of the compounds represented by the following formulas (4) to (7). ..

[In formulas (5) to (7), R ² , R ³ and R ⁴ independently represent an alkyl group, an aryl group, an arylalkyl group or a halogen atom, and R ⁵ represents a propylene group or a butylene group. ] Claims 1 to 1, wherein the acid catalyst (C) comprises at least one selected from the group consisting of maleic acid, phthalic acid, formic acid, methanesulfonic acid, p-toluenesulfonic acid monohydrate and trifluoromethanesulfonic acid. The method for producing a maleimide resin according to any one of 4. The method for producing a maleimide resin according to any one of claims 1 to 5, wherein the amount of the (C) acid catalyst added is 0.30 mol or less with respect to 1.0 mol of the (B) diamine. The method for producing a maleimide resin according to any one of claims 1 to 6, wherein the organic solvent (D) is a solvent selected from organic solvents having a boiling point of 180 ° C. or lower, or a combination of two or more. ..