Maleimide compounds, maleimide mixtures, curable compositions, cured products, prepregs, circuit boards, build-up films, semiconductor encapsulants, and semiconductor devices.

Abstract

The present disclosure aims to provide a maleimide compound that exhibits excellent heat resistance and low thermal expansion coefficient, as well as low dielectric properties, during curing, a curable composition containing the maleimide compound, and a cured product thereof. [Solution] This disclosure relates to a maleimide compound in which two or more aromatic maleimide compound structural units (A), each having one or more substituents at the meta position of an aromatic ring, are linked by methylene groups.

Description

[Technical Field]

[0001] This disclosure relates to maleimide compounds, maleimide mixtures, curable compositions, cured products, prepregs, circuit boards, build-up films, semiconductor encapsulants, and semiconductor devices. [Background technology]

[0002] Prepregs obtained by impregnating glass cloth with thermosetting resins such as epoxy resins or BT (bismaleimide-triazine) resins and then heat-drying them, laminates obtained by heat-curing the prepregs, and multilayer boards obtained by heat-curing a combination of the laminates and the prepregs are widely used as circuit board materials for electronic devices. In particular, package substrates, a type of printed wiring board that serves as an interposer for mounting semiconductors, are becoming thinner, and warping of the package substrate during mounting is becoming a problem. Therefore, there is a demand for materials with high heat resistance and low thermal expansion to suppress warping of the package substrate during mounting.

[0003] Furthermore, in recent years, with the increasing speed and frequency of signals, there is a demand for thermosetting compositions that can form cured products that maintain a sufficiently low dielectric constant and exhibit a sufficiently low dielectric loss tangent under these conditions. In particular, in recent years, for various electrical material applications, especially advanced material applications, there is a need for further improvements in performance, such as heat resistance and dielectric properties, and for materials and compositions that possess both. Maleimide resins have attracted attention as materials that possess both heat resistance and low dielectric constant / low dielectric loss tangent to meet these demands. In particular, maleimide resins used in printed circuit board materials require improved performance in terms of fine pattern machinability, dimensional stability, heat resistance, and high-frequency electrical properties. For example, Patent Document 1 discloses a compound obtained by reacting an oligomer, which is produced by reacting an aromatic amine compound and an aromatic divinyl compound having two ethenyl groups, with maleic anhydride, as a polymaleimide compound exhibiting excellent dimensional stability and low dielectric properties. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 7160151 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, while Patent Document 1 discloses technology for a polymaleimide compound that exhibits a small dimensional change rate, low dielectric loss tangent, and low moisture absorption rate during curing, it does not take low thermal expansion into consideration. Therefore, the technical problem that this disclosure aims to solve is to provide a maleimide compound that exhibits excellent heat resistance and low thermal expansion coefficient, as well as low dielectric properties, a curable composition containing the maleimide compound, and a cured product thereof during curing. [Means for solving the problem]

[0006] The present inventors, through diligent research to solve the above-mentioned problems, focused on the chemical structure of the aromatic ring linked to the maleimide group and found that by using a maleimide compound in which two or more aromatic maleimide compound structural units (A), each having one to two substituents at the meta position of the aromatic ring, are linked by methylene groups, it is possible to achieve a high-order balance of excellent heat resistance, low thermal expansion coefficient, and low dielectric properties during curing, thus completing one of the following present inventions.

[0007] [1] A maleimide compound having one to two substituents at the meta position of an aromatic ring, wherein two or more aromatic maleimide compound structural units (A) are linked by methylene groups.

[0008] [2] Aromatic maleimide compound structural unit (A1) represented by the following general formula (I-1), The methylene group represented by the following general formula (I-2) and A maleimide compound according to [1], having an aromatic maleimide compound structural unit (A2) represented by the following general formula (I-3). [Chemical formula] (In the general formula (I-1), L represents a bond and is chemically bonded to one bond of the methylene group represented by the general formula (I-2), R 11 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one bond of the group represented by the general formula (I-2), R 12 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one bond of the group represented by the general formula (I-2), X 11 each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group, n1 represents an integer of 0 or more and 3 or less, n2 represents an integer of 0 or more and 3 or less, However, in the general formula (I-1), R 11 and R 12 at least one of them is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as the substituent.) (In the general formula (I-3), L 2 represents a bond and is chemically bonded to one bond of the methylene group represented by the general formula (I-2), R 13 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one bond of the group represented by the general formula (I-2), R 14 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one bond of the group represented by the general formula (I-2), X 12 each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group, n3 represents an integer between 0 and 3, n4 represents an integer between 0 and 3, However, in the above general formula (I-3), R 13 and R 14 At least one of them is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as the substituent.

[0009] [3] A maleimide compound according to [1] or [2] having a substructure represented by the following general formula (1). [ka] (In the above general formula (1), R 1 and R 2 Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X 1 and X 2 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. ni represents an integer between 0 and 2, nii represents an integer between 0 and 2, k represents the degree of polymerization.

[0010] [4] A maleimide compound, in which an aromatic amine compound having one to two substituents at the meta position of an aromatic ring, formaldehydes, and maleic anhydride are used as reaction raw materials (1).

[0011] A curable composition containing a maleimide compound as described in any one of items [5][1] to [4].

[0012] A cured product of the curable composition described in [6][5].

[0013] [7] A prepreg having a reinforcing substrate and a semi-cured product of the curable composition described in [5] impregnated into the reinforcing substrate.

[0014] A circuit board formed by laminating the prepreg described in [8][7] and copper foil, and then heat-pressing it.

[0015] A build-up film containing the curable composition described in [9][5].

[0016] A semiconductor encapsulant containing the curable composition described in

[10] [5].

[0017] A semiconductor device comprising a cured product of the semiconductor encapsulant described in

[11]

[10] . [Effects of the Invention]

[0018] This disclosure provides a maleimide compound that exhibits excellent high heat resistance and low thermal expansion coefficient, as well as low dielectric properties, during curing, a curable composition containing the maleimide compound, and a cured product thereof. Such a maleimide compound is particularly useful in applications such as electronic component encapsulation materials. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 shows the GPC measurement results of intermediate amine compound (1) in this example. [Figure 2] Figure 2 shows the GPC measurement results of maleimide compound (1) in this example. [Figure 3] Figure 3 shows the 13C-NMR measurement results of maleimide compound (1) in this example. [Figure 4] Figure 4 shows the FD-TOF / MS measurement results of maleimide compound (1) in this example. [Figure 5] Figure 5 shows the 1H-NMR measurement results of maleimide compound (1) in this example. [Figure 6] Figure 6 shows the GPC measurement results of intermediate amine compound (2) in this example. [Figure 7] Figure 7 shows the GPC measurement results for maleimide compound (2) in this example. [Figure 8] Figure 8 shows the 13C-NMR measurement results of maleimide compound (2) in this example. [Figure 9] Figure 9 shows the FD-TOF / MS measurement results for maleimide compound (2) in this example. [Figure 10] Figure 10 shows the 1H-NMR measurement results of maleimide compound (2) in this example. [Modes for carrying out the invention]

[0020] The embodiments of the present invention (hereinafter referred to as "these embodiments") will be described in detail below, but this disclosure is not limited to the following description and can be implemented in various ways within the scope of its gist.

[0021] [term] In this specification, "structural unit" refers to a (repeating) unit of chemical structure formed during a reaction or polymerization. In other words, in a compound formed by a reaction or polymerization, it refers to a substructure other than the chemical bond structure involved in the reaction or polymerization, and is commonly known as a residue. In this specification, "reaction raw material" refers to a compound used to obtain a target compound through a chemical reaction such as combination or decomposition, and which partially constitutes the chemical structure of the target compound. Substances that act as aids to the chemical reaction, such as solvents and catalysts, are excluded. In particular, in this specification, "reaction raw material" refers to a precursor for obtaining the target maleimide compound or its precursor compound (for example, an intermediate amine compound in which two or more aromatic amine compounds are linked via a methylene group) through a chemical reaction. In this specification, "alkyl group" may be linear, branched, or cyclic, and examples include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, neopentyl group, 1,2-dimethylpropyl group, n-hexyl group, isohexyl group, (n-)heptyl group, (n-)octyl group, (n-)nonyl group, (n-)decyl group, (n-)undecyl group, (n-)dodecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, or cyclononyl group. In this specification, "cycloalkyl group" refers to a cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, or adamantyl group, etc. In this specification, the "alkenyl group" may be linear, branched, or cyclic, and examples include ethenyl group, 1-propenyl group, 2-propenyl group, 2-butenyl group, pentenyl group, hexenyl group, vinyl group, allyl group, or isopropenyl group. In this specification, the "alkoxy group" may be linear, branched, or cyclic, and examples include a methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, pentyloxy group, or hexyloxy group.

[0022] [Maleimide compounds] This disclosure relates to a maleimide compound in which two or more aromatic maleimide compound structural units (A), each having one to two substituents at the meta position of an aromatic ring, are linked by methylene groups. This makes it possible to achieve a high-level balance of excellent heat resistance, low thermal expansion coefficient, and low dielectric properties during curing. More specifically, the aromatic maleimide compound structural unit (A) of this embodiment has a skeleton in which the nitrogen atom of the maleimide group and the carbon atom of the aromatic ring are directly bonded. When at least one of the meta positions of the aromatic ring is bonded to the carbon atom constituting the aromatic ring and a substituent, the aromatic ring to which the electron-donating maleimide group is bonded becomes more stable and easier to bond with the methylene group from the viewpoint of ortho-para orientation. As a result, the aromatic ring in the aromatic maleimide compound structural unit (A) can take on a structure in which the maleimide group, substituent and methylene group are bonded in a well-balanced manner. (For example, if we assume a benzene ring as the aromatic ring, the maleimide compound as a whole can have a stable chemical structure in which a maleimide group is bonded at position 1, substituents are bonded at positions 3 and 5, and methylene groups are mainly bonded at positions 2, 4, and 6.) Therefore, in the cured product obtained by curing the maleimide compound, the mobility of the molecules constituting the cured product is suppressed by steric hindrance caused by adjacent substituents in the aromatic maleimide compound structural unit (A), and thus various thermal vibrations are suppressed. As a result, it is thought that the low dielectric properties (low dielectric loss) characteristic of the aromatic maleimide skeleton can be improved while exhibiting CTE properties (low coefficient of thermal expansion) equivalent to those of conventional maleimide resins. On the other hand, when using an aromatic maleimide compound structural unit having one to two substituents at the ortho position of the aromatic ring, there is a high tendency for the structure to have an empty meta position of the aromatic ring (i.e., a structure in which no group is linked to the meta position of the aromatic ring). As a result, intramolecular rotational motion cannot be effectively suppressed, and consequently, it is thought that it becomes difficult to reduce the coefficient of thermal expansion (for example, Comparative Example 1 described later).

[0023] The number-average molecular weight (Mn) of the maleimide compounds of this disclosure is preferably in the range of 380 to 1500, more preferably in the range of 385 to 1000, and even more preferably in the range of 390 to 800. Furthermore, the weight-average molecular weight (Mw) of the maleimide compound is preferably in the range of 380 to 3000, more preferably in the range of 385 to 2000, and even more preferably in the range of 390 to 1500. When the number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the maleimide compound are within the above range, the viscosity is low when compounded with resin, which is preferable from the viewpoint of moldability. The maleimide compounds of this disclosure are preferable in that they have excellent low dielectric constant and low dielectric loss tangent, and the molecular weight distribution (weight-average molecular weight (Mw) / number-average molecular weight (Mn)) calculated from gel permeation chromatography (GPC) measurements is in the range of 1.01 to 2.00, more preferably in the range of 1.05 to 1.80, and even more preferably in the range of 1.07 to 1.50. Furthermore, when the molecular weight distribution is wide and there are many high molecular weight components as shown in the GPC chart obtained from the GPC measurement, the proportion of high molecular weight components that contribute to flexibility increases, so compared to cured products using conventional maleimides, brittleness is suppressed and a cured product with excellent flexibility and pliability can be obtained, which is a preferred embodiment.

[0024] In this embodiment, the maleimide group equivalent per gram of maleimide compound is preferably 170 to 400 (g / equivalent), more preferably 180 to 350 (g / equivalent), and even more preferably 185 to 300 (g / equivalent). When the maleimide group equivalent is within the above range, it is preferable from the viewpoint of achieving both heat resistance / CTE characteristics and low dielectric properties. The maleimide group equivalents used herein are calculated using the method described in the examples below.

[0025] The maleimide compound of this embodiment has two or more aromatic maleimide compound structural units (A) and a methylene group linking the two or more aromatic maleimide compound structural units (A), and it is preferable that the aromatic maleimide compound structural unit (A) has one to two substituents of one or more carbon atoms at the meta position of the aromatic ring. The number of methylene group units is preferably 1 to 10 moles, more preferably 1 to 9 moles, and even more preferably 1 to 8 moles, relative to the total maleimide compound (1 mole). When the number of methylene group units is within the above range, it is preferable from the viewpoint of moldability of the resin and heat resistance and low dielectric properties when it is cured. In this specification, the number of methylene units (= structural units) per mole of the maleimide compound is: 1 It can be calculated from 1H-NMR measurements. More specifically, it can be calculated using the ratio of peak areas derived from the methylene group linking the two or more aromatic maleimide compound structural units (A) and the ratio of peak areas derived from the alkenyl group in the maleimide group or the hydrogen atoms on the benzene ring. Furthermore, the number of methylene units relative to the entire maleimide compound (1 mole) can be calculated using methods such as GPC measurement or FD / TOF / MS measurement. From the obtained molecular weight information and the repeating structural units of the maleimide compound, the number of methylene groups linking two or more aromatic maleimide compound structural units (A) and the number of aromatic maleimide compound structural units (A) can be calculated.

[0026] The aromatic maleimide compound structural unit (A) of this embodiment has a skeleton in which an aromatic ring (or carbon atoms thereof) is directly bonded to the nitrogen atom of a maleimide group, and at least one of the meta positions (e.g., position 3 and / or position 5) of the aromatic ring is bonded to a substituent and a carbon atom constituting the aromatic ring, and 1 to 4 hydrogen atoms have been removed from the aromatic ring, resulting in a monovalent to tetravalent group. Therefore, having 1 to 2 substituents at the meta position of the aromatic ring means that a substituent is bonded to at least one of the carbon atoms at the meta position of the aromatic ring bonded to the nitrogen atom of the maleimide group. The aromatic ring is preferably monocyclic and may include aromatic hydrocarbon rings and aromatic heterocyclic rings. The aromatic hydrocarbon ring is preferably a benzene ring. Examples of aromatic heterocyclic rings include heterosix-membered rings such as pyran rings or pyridine rings. Examples of the substituents include monovalent organic groups, and for example, alkyl groups having 1 to 6 carbon atoms or alkoxy groups having 1 to 6 carbon atoms are particularly preferred. In this specification, "organic group" refers to a group whose chemical structure is formed by an organic compound containing one or more carbon atoms being transformed into a 1- to 4-valent group. In other words, an "organic group" is an atomic group obtained by removing one to four hydrogen atoms from an organic compound containing one or more carbon atoms. Therefore, the organic group may contain one or more atoms selected from the group consisting of hydrogen atoms, nitrogen atoms, oxygen atoms, halogen atoms, sulfur atoms, and phosphorus atoms, in addition to carbon atoms. Specific examples of the organic group include, preferably, a group having a hydrocarbon group; more preferably, a group having a linear or branched aliphatic hydrocarbon group or a cyclic hydrocarbon group; even more preferably, a group having a linear or branched saturated aliphatic hydrocarbon group, a cyclic hydrocarbon group having one or more unsaturated bonds, or a group having an aromatic ring; and even more preferably, an alkyl group, an alkenyl group, or an alkoxy group. Furthermore, the number of carbon atoms in the "organic group" as used herein may preferably be an integer from 1 to 15, more preferably an integer from 1 to 10, and even more preferably an integer from 1 to 6.

[0027] Preferred embodiments of the aromatic maleimide compound structural unit (A) in this embodiment include, for example, the aromatic maleimide compound structural unit (A1) represented by the following general formula (I-1) and the aromatic maleimide compound structural unit (A2) represented by the following general formula (I-3). For the sake of clarity in this specification, in order to distinguish between adjacent aromatic maleimide compound structural units (A) that constitute the maleimide compound of this embodiment via a methylene group, aromatic maleimide compound structural unit (A1) represented by general formula (I-1) and aromatic maleimide compound structural unit (A2) represented by general formula (I-3) are defined separately. Therefore, aromatic maleimide compound structural unit (A1) represented by general formula (I-1) and aromatic maleimide compound structural unit (A2) represented by general formula (I-3) may be the same as or different from each other. Furthermore, the term "aromatic maleimide compound structural unit (A)" is a general term for aromatic maleimide compound structural unit (A1) and aromatic maleimide compound structural unit (A2).

[0028] The maleimide compound of this embodiment comprises an aromatic maleimide compound structural unit (A1) represented by the following general formula (I-1), and the methylene group represented by the following general formula (I-2), It is preferable that the aromatic maleimide compound structural unit (A2) is represented by the following general formula (I-3). [ka] (In the above general formula (I-1), L 1 This represents a single bond, which is chemically bonded to one of the bonds of the methylene group represented by the general formula (I-2) above. R 11 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group represented by general formula (I-2) bonded to one of its bonds. R 12 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2). X 11 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n1 represents an integer between 0 and 3, n² represents an integer between 0 and 3, However, in the above general formula (I-1), R 11 and R 12 At least one of them is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as the substituent. (In the general formula (I-2) above, * represents a bond with another atom.) [ka] (In the above general formula (I-3), L 2 This represents a bond, which is chemically bonded to one of the bonds of the methylene group represented by the general formula (I-2) above. R 13 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2). R 14 Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2). X 12 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n3 represents an integer between 0 and 3, n4 represents an integer between 0 and 3, However, in the above general formula (I-3), R 13 and R 14 At least one of them is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as the substituent.

[0029] In the above general formula (I-1), L 1 * represents a single bond, and this single bond can be chemically bonded to one of the bonds of the methylene group represented by the general formula (I-2) above. However, when n2 is 0, L is a single bond. 1 It does not exist. However, if n2 is 0, R 11 or R 12Only one of the two forms a bonding site, and is bonded to one of the bonding sites of the methylene group represented by general formula (I-2)*. That is, when n2 is 0, the aromatic maleimide compound structural unit (A1) represented by general formula (I-1) and the methylene group represented by general formula (I-2) can be the structural unit represented by the following general formula (I-1.1) or the structural unit represented by the following general formula (I-1.2). In other words, if n2 is 0, R 11 or R 12 It can also be said that one of the two forms a bond (or single bond), and this bond combines with one of the bonds of the methylene group represented by general formula (I-2) to form a structural unit represented by the following general formula (I-1.1) or the following general formula (I-1.2). [ka] (In the above general formula (I-1.1), R 11 Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X 11 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n1 represents an integer between 0 and 3 (inclusive). Note that the * bond of the methylene group in the above general formula (I-1.1) is the same as the L in the above general formula (I-3). 2 It is combined with, or R in the above general formula (I-3) 13 It is directly bonded to the benzene ring, or R in the above general formula (I-3). 14 It is directly bonded to the benzene ring. [ka] (In the above general formula (I-1.2), R 12 Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X 11Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n1 represents an integer between 0 and 3 (inclusive). Note that the * bond of the methylene group in the above general formula (I-1.2) is the same as the L in the above general formula (I-3). 2 It is combined with, or R in the above general formula (I-3) 13 It is directly bonded to the benzene ring, or R in the above general formula (I-3). 14 It is directly bonded to the benzene ring.

[0030] In the above general formula (I-1), L 1 Possible positions include 2nd, 4th, or 6th place. Also, L 1 The number n2 is preferably 0, 1, or 2, and more preferably 1 or 2. In addition, in the above general formula (I-1), R 11 and R 12 It allows hydrogen atoms. However, R 11 or R 12 Even if it is a hydrogen atom, if that hydrogen atom is L 1 It will not be replaced by this.

[0031] In the above general formula (I-1), R 11 It is more preferable that the bond is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2) (=bond or single bond), and a hydrogen atom or an alkyl group having 1 to 6 carbon atoms is even more preferable. In the above general formula (I-1), R 12 It is more preferable that the bond is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2) (=bond or single bond), and a hydrogen atom or an alkyl group having 1 to 6 carbon atoms is even more preferable. In the above general formula (I-1), R 11 and R 12At least one of these is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. This allows the meta position of the aromatic ring to be capped with a substituent having 1 or more carbon atoms, and it is expected that the rotational motion of the molecule in the cured product when the maleimide compound is cured will be suppressed by the adjacent substituent. As a result, it is thought that the compound can exhibit CTE properties (low coefficient of thermal expansion) equivalent to those of conventional maleimide resins, and the low dielectric properties (low dielectric loss) characteristic of the aromatic maleimide skeleton can be further improved.

[0032] In the above general formula (I-1), X 11 Each of these is preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group, with an alkyl group having 1 to 6 carbon atoms being more preferred. X 11 The possible positions are the 2nd, 4th, or 6th position, but the 2nd and / or 6th position is preferred. When substituents are positioned at the meta and ortho positions of the benzene ring in the aromatic maleimide compound structural unit (A1) represented by general formula (I-1), an excluded volume effect occurs in the cured product obtained by curing the maleimide compound due to the amplitude of thermal vibrations between adjacent substituents. This is thought to cancel out the vibrations of each substituent in the entire molecule, thereby further suppressing intramolecular rotational motion. As a result, it is thought that CTE properties equivalent to those of conventional maleimide resins can be achieved, and the low dielectric properties (low dielectric loss) characteristic of the aromatic maleimide skeleton can be further improved.

[0033] In the above general formula (I-1), n1 represents an integer between 0 and 3, preferably between 0 and 2, and more preferably 1. In the above general formula (I-1), n2 represents an integer between 0 and 3, with 1 or 2 being more preferable.

[0034] In the above general formula (I-2), * represents a bond indicating a bond with another atom. More specifically, one bond of the methylene group represented by general formula (I-2), *, is chemically bonded to the aromatic maleimide compound structural unit (A1) represented by general formula (I-1), and the other bond of the methylene group, *, is chemically bonded to the aromatic maleimide compound structural unit (A2) represented by general formula (I-3). Furthermore, it is preferable that 1 to 4 (preferably 1 to 2) methylene groups represented by general formula (I-2) are bonded to one unit of the aromatic maleimide compound structural unit (A1) represented by general formula (I-1), and that 1 to 4 (preferably 1 to 2) methylene groups represented by general formula (I-2) are bonded to one unit of the aromatic maleimide compound structural unit (A2) represented by general formula (I-3). The maleimide compound of this embodiment is preferable from the viewpoint of heat resistance and CTE (low coefficient of thermal expansion) because, since two or more aromatic maleimide compounds are bonded via methylene groups, adjacent aromatic maleimide functional groups are located relatively close to each other.

[0035] In the above general formula (I-3), L 2 represents a single bond, and this single bond can be chemically bonded to the other bond of the methylene group represented by the general formula (I-2) above. However, when n4 is 0, L is a single bond. 2 It does not exist. However, if n4 is 0, R 13 or R 14 Only one of the two forms a bonding site, and is bonded to one of the bonding sites of the methylene group represented by general formula (I-2)*. That is, when n4 is 0, the aromatic maleimide compound structural unit (A2) represented by general formula (I-3) and the methylene group represented by general formula (I-2) may be the structural unit represented by the following general formula (I-3.1) or the structural unit represented by the following general formula (I-3.2). In other words, if n4 is 0, R 13 or R 14It can also be said that one of the two forms a bond (or single bond), and this bond combines with the other bond of the methylene group represented by general formula (I-2) to form a structural unit represented by the following general formula (I-3.1) or the following general formula (I-3.2). [ka] (In the above general formula (I-3.1), R 13 Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X 12 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n3 represents an integer between 0 and 3 (inclusive). Note that the * bond of the methylene group in the above general formula (I-3.1) is the same as the L in the above general formula (I-1). 1 It is combined with, or R in the above general formula (I-1) 11 It is directly bonded to the benzene ring, or R in the above general formula (I-1) 12 It is directly bonded to the benzene ring. [ka] (In the above general formula (I-3.2), R 14 Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X 12 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n3 represents an integer between 0 and 3 (inclusive). Note that the * bond of the methylene group in the above general formula (I-3.2) is the same as the L in the above general formula (I-1). 1 It is combined with, or R in the above general formula (I-1) 11 It is directly bonded to the benzene ring, or R in the above general formula (I-1) 12It is directly bonded to the benzene ring.

[0036] In the above general formula (I-3), L 2 Possible positions include 2nd, 4th, or 6th place. Also, L 3 The number n4 is preferably 0, 1, or 2, and more preferably 1 or 2. In addition, in the above general formula (I-3), R 13 and R 14 It allows hydrogen atoms. However, R 13 or R 14 Even if it is a hydrogen atom, if that hydrogen atom is L 2 It will not be replaced by this.

[0037] In the above general formula (I-3), R 13 It is more preferable that the bond is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2) (=bond or single bond), and a hydrogen atom or an alkyl group having 1 to 6 carbon atoms is even more preferable. In the above general formula (I-3), R 14 It is more preferable that this is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2) (=bond or single bond). In the above general formula (I-3), R 13 and R 14 At least one of these is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. This allows the meta position of the aromatic ring to be capped with a substituent having 1 or more carbon atoms, and it is expected that the rotational motion of the molecule in the cured product when the maleimide compound is cured will be suppressed by the adjacent substituent. As a result, it is thought that the compound can exhibit CTE properties (low coefficient of thermal expansion) equivalent to those of conventional maleimide resins, and the low dielectric properties (low dielectric loss) characteristic of aromatic maleimides can be further improved.

[0038] In the above general formula (I-3), X 12Each of these is preferably an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group, with an alkyl group having 1 to 6 carbon atoms being more preferred. X 13 The possible positions are the 2nd, 4th, or 6th position, but the 2nd and / or 6th position is preferred. When substituents are placed at the meta and ortho positions of the benzene ring in the aromatic maleimide compound structural unit (A2) represented by general formula (I-3), an excluded volume effect occurs in the cured product obtained by curing the maleimide compound due to the amplitude of thermal vibrations between adjacent substituents. This is thought to cancel out the vibrations of each substituent in the entire molecule, thereby further suppressing intramolecular rotational motion. As a result, it is thought that CTE properties equivalent to those of conventional maleimide resins can be achieved, and the low dielectric properties (low dielectric loss) characteristic of the aromatic maleimide skeleton can be further improved.

[0039] In the above general formula (I-3), n3 represents an integer between 0 and 3, preferably between 0 and 2, and more preferably 1. In the above general formula (I-3), n4 represents an integer between 0 and 3, with 1 or 2 being more preferable.

[0040] In the maleimide compound of this embodiment, the content of the aromatic maleimide compound structural unit (A1) represented by general formula (I-1) may be preferably 1 to 99% by mass, more preferably 2 to 98% by mass, relative to the total maleimide compound (100% by mass). In the maleimide compound of this embodiment, the content of the methylene group represented by general formula (I-2) may be preferably 0.1 to 50.0% by mass, more preferably 0.5 to 50.0% by mass, based on the total maleimide compound (100% by mass). In the maleimide compound of this embodiment, the content of the aromatic maleimide compound structural unit (A2) represented by general formula (I-3) may be preferably 1 to 99% by mass, more preferably 2 to 99% by mass, relative to the total maleimide compound (100% by mass).

[0041] The maleimide compound of this embodiment preferably has a partial structure represented by the following general formula (1). [Chemical Formula] (In the above general formula (1), R 1 and R 2 each independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, X 1 and X 2 each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group or a cyano group, ni represents an integer of 0 or more and 2 or less, nii represents an integer of 0 or more and 2 or less, k represents the degree of polymerization. In the above general formula (1), * is a bond representing a bond with other atoms.)

[0042] In the above general formula (1), R 1 and R 2 are each independently preferably an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. R 1 and R 2 being an alkyl group having 1 to 6 carbon atoms is preferable from the viewpoint of low dielectric characteristics.

[0043] In the above general formula (1), X 1 and X 2 each independently represent an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group or a cyano group, more preferably an alkyl group having 1 to 6 carbon atoms. Also, the position of X 1 is not particularly limited, and a total of ni can be present at the 2nd, 3rd, 4th or 6th position of the benzene ring of the above general formula (1). Among them, X 1 is preferably present at the ortho position and / or meta position of the benzene ring of the above general formula (1). Similarly, X2 The position of is not particularly restricted, and a total of nii can be present at the 2nd, 3rd, 4th, or 6th positions of the benzene ring in the general formula (1) above. Among them, X 2 It is preferable that it is located at the ortho and / or meta positions of the benzene ring of the general formula (1) above. This cancels out the molecular vibrations of each substituent in the maleimide compound molecule as a whole, thereby further suppressing intramolecular rotational motion. As a result, it is possible to achieve CTE properties equivalent to those of conventional maleimide resins, while also exhibiting the low dielectric properties (low dielectric loss) characteristic of aromatic maleimide skeletons.

[0044] In the above general formula (1), ni is preferably 0 or 1. Similarly, nii is preferably 0 or 1. In the above general formula (1), k represents the degree of polymerization, preferably in the range of greater than 0 and 10 or less, more preferably in the range of greater than 0 and 9 or less, and even more preferably in the range of greater than 0 and 8 or less. When the degree of polymerization is within the above range, the probability of approximately 2 to 10 aromatic maleimide compound structural units (A) being present per maleimide compound molecule increases, which is preferable from the viewpoint of heat resistance and CTE properties (low coefficient of thermal expansion).

[0045] (Preferred form of maleimide compound) A suitable maleimide compound for this embodiment may be a compound represented by the following general formula (2). [ka] (In the above general formula (2), R 1 and R 2 Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X 1 and X 2 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. ni represents an integer between 0 and 2, nii represents an integer between 0 and 2, (m represents the degree of polymerization.)

[0046] In the above general formula (2), R 1 and R 2 Each of these is preferably an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. R 1 and R 2 However, alkyl groups having 1 to 6 carbon atoms are preferable from the viewpoint of low dielectric properties.

[0047] In the above general formula (2), X 1 and X 2 Each of these is preferably an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. Also, X 1 The position of is not particularly restricted, and a total of 2 can be present at the 2nd, 3rd, 4th, or 6th positions of the benzene ring in the general formula (2) above. Among them, X 1 It is preferable that it is located at the ortho and / or meta positions of the benzene ring of the general formula (2) above. Similarly, X 2 The position of is not particularly restricted, and a total of nii can be present at the 2nd, 3rd, 4th, or 6th positions of the benzene ring in the general formula (2) above. Among them, X 2 It is preferable that it is located at the ortho and / or meta positions of the benzene ring of the general formula (2) above. This cancels out the vibrations of each substituent within the maleimide compound molecule, thereby further suppressing intramolecular rotational motion. As a result, it is believed that the cured product obtained by curing the maleimide compound can exhibit excellent low thermal expansion properties and low dielectric properties (low dielectric loss).

[0048] In the above general formula (2), ni is preferably 0 or 1. Similarly, nii is preferably 0 or 1. In the above general formula (2), m represents the degree of polymerization, preferably in the range of greater than 0 and 10 or less, more preferably in the range of greater than 0 and 9 or less, and even more preferably in the range of greater than 0 and 8 or less. When the degree of polymerization is within the above range, there are about 2 to 10 aromatic maleimide compound structural units (A) per maleimide compound molecule, which is preferable from the viewpoint of heat resistance and CTE properties (low coefficient of thermal expansion).

[0049] (Another embodiment of maleimide compounds) To specify the maleimide compounds of this disclosure from another perspective, the maleimide compounds may be compounds reacted with an aromatic amine compound having one to two substituents at the meta position of an aromatic ring, formaldehydes, and maleic anhydride as reaction starting materials (1). The following describes the components of the reaction raw material (1) for the maleimide compound: aromatic amine compounds having one to two substituents at the meta position of the aromatic ring, formaldehydes, and maleic anhydride. After that, other preferred forms of the maleimide compound and methods for producing the maleimide compound will be described.

[0050] <Aromatic amine compounds> The aromatic amine compound in this embodiment has an aromatic ring to which an amino group (-NH2 or substituted amino group) is bonded, and one to two substituents are bonded to the meta position of the aromatic ring. The substituents may be, for example, organic groups having one to fifteen carbon atoms. The aromatic ring forming the central structure of the aromatic amine compound is preferably monocyclic and may include an aromatic hydrocarbon ring and an aromatic heterocycle. The aromatic hydrocarbon ring is preferably a benzene ring. Examples of aromatic heterocycles include heterosix-membered rings such as a pyran ring or a pyridine ring. Furthermore, the aromatic amine compound in this embodiment has an aromatic ring to which a -NH2 group without a substituted amino group is bonded, and it is more preferable that one to two substituents are bonded to the meta position of the aromatic ring. Furthermore, the substituted amino group is -NR a R b It is a monovalent group represented by R a R represents an alkyl group with 1 to 3 carbon atoms.b This represents an alkyl group with 1 to 3 carbon atoms.

[0051] In the aromatic amine compound of this embodiment, the substituent bonded to the meta position of the aromatic ring of the aromatic amine compound is preferably an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. When the number of carbon atoms of the substituent is in the range of 1 to 6, the effects achieved by the present invention (heat resistance and thermal expansion coefficient) become even more pronounced.

[0052] A preferred form of aromatic amine compound will be described, using the case where the aromatic ring of the aromatic amine compound in this embodiment is a benzene ring as an example. Specific examples of aromatic amine compounds in this embodiment include, for example, 2,5-xylidine, 2,3-xylidine, 3,6-xylidine, 3,4-xylidine, 3,5-xylidine, 3,5-diisopropylaniline, ethylmethylaniline (e.g., ethylmethylaniline in which one of the 2,3, 3,6, 3,4, or 3,5 positions is a methyl group and the other is an ethyl group), m-toluidine, m-ethylaniline, m-isopropylaniline, m-propylaniline, m-butylaniline, methylisopropylaniline (e.g., methylisopropylaniline in which one of the 2,3, 3,6, 3,4, or 3,5 positions is a methyl group and the other is an isopropyl group), or ethylbutylaniline (e.g., ethylbutylaniline in which one of the 2,3, 3,6, 3,4, or 3,5 positions is an ethyl group and the other is a butyl group). Furthermore, the butyl includes n-butyl, tert-butyl, and sec-butyl. In this embodiment, the aromatic amine compounds may be used individually or in combination of two or more.

[0053] The aromatic amine compound, which is an essential reaction raw material (1) in this embodiment, can be represented by, for example, the following general formula (a). [ka] (In the above general formula (a), R1a R represents a hydrogen atom or an organic group, preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. 2a This represents a hydrogen atom or an organic group, preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X 1a Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group, n a X represents an integer between 0 and 3. There are multiple X values. 1a They may be the same or different. However, R 1a and R 2a At least one of them is the aforementioned organic group.

[0054] In the above general formula (a), R 1a R is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. In the above general formula (a), 2a The alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl groups having 1 to 6 carbon atoms and 1 to 3 carbon atoms are the same as described above. R 1a and R 2a At least one of these is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms.

[0055] In the above general formula (a), X 1a Each of these is independently an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, and is more preferably an alkyl group having 1 to 6 carbon atoms. In the above general formula (a), n a It is preferable that X is 0, 1, or 2. 1a If multiple alkyl groups exist, they may be the same alkyl group or different alkyl groups. In this embodiment, the aromatic amine compound represented by the general formula (a) may be used alone or in combination of two or more types.

[0056] <Formaldehyde> In this embodiment, formaldehydes include not only compounds having an aldehyde group (-CHO), but also compounds that produce formaldehyde in water or solution. Examples of such formaldehydes include formaldehyde and paraformaldehyde.

[0057] In this embodiment, the reaction raw material (1) for the maleimide compound is preferably such that the molar ratio of formaldehydes to aromatic amine compounds in the reaction raw material (1) is 20 / 1 to 1 / 1, and more preferably 10 / 1 to 1 / 1.

[0058] <Maleic anhydride> In this embodiment, maleic anhydride is an essential component of the reaction raw material (1) for the maleimide compound, and is used in the reaction to maleimideize amino groups (including -NH2 and substituted amino groups) derived from aromatic amine compounds, as will be explained later in the section on the method of producing the maleimide compound.

[0059] <Method for producing maleimide compounds> The method for producing the maleimide compounds of this disclosure will be described below. The maleimide compound of this embodiment is not particularly limited in its manufacturing method and may be manufactured using an aromatic amine compound, formaldehydes, and maleic anhydride as reaction raw materials (1), or in any way as long as it has a structural unit represented by the general formula (1) described above. An example of a method for manufacturing the maleimide compound of this disclosure is a manufacturing method comprising the following steps (1) and (2). Step (1): A step of reacting an aromatic amine compound with formaldehydes as a reaction raw material (2) to obtain the intermediate amine compound (1) in this embodiment; Step (2): A step of reacting the intermediate amine compound (1) obtained in step (1) with maleic anhydride as a reaction raw material (3) to obtain the maleimide compound of the present disclosure. Specifically, the method for producing the maleimide compound of this embodiment preferably comprises a step (1) in which an aromatic amine compound and formaldehydes are reacted under a solid acid catalyst (also referred to as a crosslinking step), and a step (2) in which the intermediate amine compound (1) produced in step (1) is condensed with maleic anhydride (also referred to as a condensation step). The following describes each step of the method for producing the maleimide compound of this disclosure.

[0060] <<Process (1): Manufacturing process for intermediate amine compound (1)>> The following describes the manufacturing process of the intermediate amine compound (1) in this embodiment. Step (1) in this embodiment is not particularly limited, but for example, it is a step of reacting the above-mentioned aromatic amine compound with the above-mentioned formaldehydes in the presence of an acid catalyst. This can generate an intermediate amine compound (1).

[0061] Regarding the blending ratio of the aromatic amine compound and the formaldehyde compounds, considering the balance of moldability and curability properties during the production of the resulting cured product, it is preferable that the molar ratio of the formaldehyde compounds is 0.05 to 1 mole per mole of the aromatic amine compound, and more preferably 0.1 to 1 mole. Furthermore, the specific methods for carrying out the above reaction generally involve charging all the raw materials together and reacting them at a predetermined temperature, or charging the aromatic amine compound and the acid catalyst and reacting them dropwise while maintaining the predetermined temperature with formaldehydes or the like. In this case, the dropwise addition time is usually 0.1 to 24 hours, and preferably 12 hours or less. After the reaction, if a solvent is used, the solvent and unreacted products can be removed by distillation as needed to obtain the intermediate amine compound (1). If no solvent is used, the target intermediate amine compound (1) can be obtained by distilling off the unreacted products.

[0062] Examples of acid catalysts used in step (1) of this embodiment include inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid; organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid; solid acids such as activated clay, acid clay, silica alumina, zeolite, and strong acid ion exchange resin; and heteropolyhydrochloric acid. However, solid acids that can be easily removed by filtration after the reaction are preferred from the viewpoint of ease of handling. When using other acids, it is preferable to neutralize with a base and wash with water after the reaction. The amount of the acid catalyst is typically 1 to 100 parts by mass per 100 parts by mass of the total raw materials (aromatic amine compounds and formaldehydes), but 1 to 60 parts by mass is preferred from the viewpoint of handling and economic efficiency. The reaction temperature can usually be in the range of 100 to 270°C, but 100 to 220°C is preferred to suppress the formation of isomer structures and avoid side reactions such as thermal decomposition.

[0063] In step (1) of this embodiment, the reaction time for the crosslinking reaction is usually in the range of 1 to 48 hours, but preferably in the range of 1 to 30 hours, because if it is too short the reaction does not proceed completely, and if it is too long side reactions such as thermal decomposition of the product occur. In the method for producing the intermediate amine compound (1) in this embodiment, since the aniline derivative also serves as the solvent, it is not necessarily required to use other solvents, but it is possible to use a solvent. For example, when reacting with divinylbenzene as a raw material, a method may be adopted in which an azeotropic dehydration solvent such as toluene, xylene, or chlorobenzene is used, and if necessary, water contained in the catalyst, etc. is azeotropically dehydrated, the solvent is removed by distillation, and then the reaction is carried out within the above reaction temperature range.

[0064] The intermediate amine compound (1) obtained by the above step (1) preferably has a substructure represented by the following general formula (3), and more preferably a compound represented by the following general formula (4). [ka] [ka] (In the above general formulas (3) and (4), R 1 and R 2 Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X 1 and X 2 Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. ni represents an integer between 0 and 2, nii represents an integer between 0 and 2, k represents the degree of polymerization, and m also represents the degree of polymerization.

[0065] In the above general formulas (3) and (4), R 1 and R 2 Each of these is preferably an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. R 1 and R 2 However, alkyl groups having 1 to 6 carbon atoms are preferable from the viewpoint of low dielectric properties.

[0066] In the above general formulas (3) and (4), X 1 and X 2 Each of these is preferably an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. Also, X 1 The position of is not particularly restricted, and a total of 2 can be present at the 2nd, 3rd, 4th, or 6th positions of the benzene ring in the general formulas (3) and (4) above. Among them, X 1 It is preferable that it is located at the ortho and / or meta positions of the benzene ring of the above general formulas (3) and (4). Similarly, X 2The position of is not particularly restricted, and a total of nii can be present at the 2nd, 3rd, 4th, or 6th positions of the benzene ring in the general formulas (3) and (4) above. In particular, X 2 It is preferable that it is located at the ortho and / or meta positions of the benzene ring of the above general formulas (3) and (4).

[0067] In the above general formulas (3) and (4), ni is preferably 0 or 1. Similarly, nii is preferably 0 or 1. In the above general formula (3), k represents the degree of polymerization, preferably in the range of greater than 0 and 10 or less, more preferably in the range of greater than 0 and 9 or less, and even more preferably in the range of greater than 0 and 8 or less. In the above general formula (4), m represents the degree of polymerization, preferably in the range of greater than 0 and 10 or less, more preferably in the range of greater than 0 and 9 or less, and even more preferably in the range of greater than 0 and 8 or less.

[0068] The number-average molecular weight (Mn) of the intermediate amine compound (1) of this disclosure is preferably in the range of 300 to 1500, more preferably in the range of 305 to 1000, and even more preferably in the range of 310 to 800. Furthermore, the weight-average molecular weight (Mw) of the intermediate amine compound (1) is preferably in the range of 300 to 3000, more preferably in the range of 305 to 2000, and even more preferably in the range of 310 to 1500. In this embodiment, the amine equivalent of the intermediate amine compound (1) is preferably 80 to 320 g / equivalent, and more preferably 85 to 280 g / equivalent. In this specification, the amine equivalent of intermediate amine compound (1) is measured by a method conforming to the neutralization titration method specified in JIS K 0070 (1992), as shown in the examples described below.

[0069] <<Step (2): Maleimidization>> Step (2) in this embodiment is a step of reacting the intermediate amine compound (1) obtained in step (1) with maleic anhydride. The amino group (including -NH2 and substituted amino groups) of the intermediate amine compound (1) can be subjected to a maleimidation reaction to form a chemical structure in which the amino group is substituted with an N-substituted maleimide ring, thereby obtaining the maleimide compound of this disclosure. In this embodiment, the intermediate amine compound (1) represented by the general formula (3) or (4) obtained in step (1) is charged into a reactor, dissolved in a suitable solvent, and then reacted with maleic anhydride in the presence of a catalyst. After the reaction, unreacted maleic anhydride or other impurities are removed by washing with water or the like, and the solvent is removed by reduced pressure to obtain the target maleimide compound. A dehydrating agent may also be used during the reaction if necessary.

[0070] Examples of organic solvents used in step (2) of this embodiment include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, and acetophenone; aprotic solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, acetonitrile, and sulfolane; cyclic ethers such as dioxane and tetrahydrofuran; esters such as ethyl acetate and butyl acetate; and aromatic solvents such as benzene, toluene, and xylene. These may be used individually or in combination.

[0071] In step (2) of this embodiment, the mixing ratio of the intermediate amine compound (1) and maleic anhydride is preferably such that the equivalent ratio of maleic anhydride to the amine equivalent of the intermediate amine compound (1) is in the range of 1 to 5, more preferably 1 to 3, and the reaction is carried out in an organic solvent with a mass ratio of 0.01 to 100, preferably 0.1 to 10, relative to the total amount of the intermediate amine compound (1) and maleic anhydride.

[0072] Examples of catalysts that can be used in step (2) of this embodiment include acetates of nickel, cobalt, sodium, calcium, iron, lithium, manganese, etc., inorganic salts such as chlorides, bromides, sulfates, and nitrates, inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid, organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid, solid acids such as activated clay, acid clay, silica alumina, zeolite, and strong acid ion exchange resins, and heteropolyhydrochloric acid, but toluenesulfonic acid is particularly preferred.

[0073] Examples of dehydrating agents used in step (2) of this embodiment include lower aliphatic carboxylic acid anhydrides such as acetic anhydride, propionic anhydride, and butyric anhydride; oxides such as phosphorus pentoxide, calcium oxide, and barium oxide; inorganic acids such as sulfuric acid; and porous ceramics such as molecular sieves. However, acetic anhydride can be used. There are no particular restrictions on the amount of catalyst and dehydrating agent used in step (2) of this embodiment, but typically, 0.0001 to 1.0 moles of catalyst, preferably 0.01 to 0.5 moles, and 1 to 3 moles of dehydrating agent, preferably 1 to 1.5 moles, can be used per equivalent of the amino group (-NH2) of the intermediate amine compound (1). In step (2) of this embodiment, the reaction conditions for maleimidation are as follows: the intermediate amine compound (1) and maleic anhydride are charged and reacted at a temperature range of 10 to 100°C, preferably 30 to 60°C, for 0.5 to 12 hours, preferably 1 to 4 hours. Then, the catalyst is added and the reaction is carried out at a temperature range of 90 to 130°C, preferably 105 to 120°C, for 1 to 24 hours, preferably 1 to 10 hours.

[0074] (Other embodiments of maleimide compounds) The maleimide compounds of this disclosure may be mixtures. That is, the maleimide compounds of this disclosure may be mixtures containing, for example, two or more maleimide compounds in which two or more aromatic maleimide compound structural units (A) having one or more substituents at the meta position of an aromatic ring are linked by methylene groups, and preferably a mixture of two or more compounds having a substructure represented by the above general formula (1).

[0075] [Curable composition] The curable composition of this disclosure contains the maleimide compound described above. Because the maleimide compound of this embodiment has excellent handling properties and contributes to low thermal expansion, heat resistance, and low dielectric constant / low dielectric loss tangent, the cured product obtained from the curable composition containing the maleimide compound has excellent low thermal expansion, heat resistance, and dielectric properties.

[0076] The curable composition of this disclosure may contain a curing agent, and may further contain various additives as needed, such as a curing accelerator, a silane coupling agent, a curing catalyst, a mold release agent, a pigment, an emulsifier, a non-halogenated flame retardant, an inorganic filler, a flame retardant (e.g., an inorganic phosphorus-based flame retardant, an organophosphorus-based flame retardant, a halogen-based flame retardant), and a solvent. The content of the additive may be preferably 0% to 90% by mass, and more preferably 0.01% to 85% by mass, relative to the total curable composition (100% by mass). Furthermore, other resins may be added as curing agents, provided that they do not impair the purpose of this disclosure. Suitable other resins may include epoxy resins, phenolic resins, activated ester resins, cyanate resins, polyphenylene ether resins, benzoxazine resins, styrene-maleic anhydride copolymers, polybutadiene and its modified products, polyacetal resins, polyvinyl alcohol resins, liquid crystal polymers, fluororesins, polystyrene, polyethylene, polyimide resins, silicone gels, silicone oils, and the like. In the curable composition of this embodiment, the content of the curing agent is preferably 0% to 90% by mass, more preferably greater than 0% to 85% by mass, and more preferably 2% to 80% by mass, based on the total curable composition (100% by mass).

[0077] The curable composition of this embodiment may optionally contain a curing catalyst. The curing catalyst is not particularly limited and includes, for example, organic peroxides (e.g., benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, lauroyl peroxide, di-t-butyl peroxide, t-butyl hydroperoxide, methyl ethyl ketone peroxide, t-butyl perbenzoate, etc.), azo compounds (e.g., azobisisobutyronitrile), and free radicals (e.g., azobisisobutyronitrile, garbinoxyl, etc.).

[0078] The curable composition of this embodiment may be used in combination with a curing accelerator as needed. Various curing accelerators can be used, and for example, the addition of polymerization initiators such as organic peroxides and azo compounds, or basic catalysts such as phosphine compounds and tertiary amines is effective. Specific examples of curing accelerators include benzoyl peroxide, dicumyl peroxide, azobisisobutyronitrile, triphenylphosphine, TPP-MK, TPP-K, triethylamine, and imidazoles. The curing accelerator can be used alone or in combination of two or more. The amount of curing accelerator in this embodiment is preferably 0.05 to 5% by mass of the total curable composition.

[0079] Examples of the above-mentioned flame retardants include inorganic phosphorus-based flame retardants, organophosphorus-based flame retardants, halogen-based flame retardants, and non-halogen-based flame retardants. In order to exhibit flame retardancy to the extent that the purpose is not impaired, it is more preferable to incorporate a non-halogen-based flame retardant that is substantially free of halogen atoms into the curable composition of this embodiment. Examples of the non-halogen-based flame retardants include phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, organometallic salt-based flame retardants, etc., and these can be used alone or in combination.

[0080] The curable composition of this embodiment may contain inorganic fillers as needed. Examples of inorganic fillers include fused silica, crystalline silica, alumina, silicon nitride, and aluminum hydroxide. When the amount of inorganic filler is particularly large, it is preferable to use fused silica. The fused silica can be used in either crushed or spherical form, but it is preferable to mainly use spherical silica in order to increase the amount of fused silica and suppress the increase in the melt viscosity of the molding material. To further increase the amount of spherical silica, it is preferable to appropriately adjust the particle size distribution of the spherical silica. The filling rate is preferably high, taking into consideration flame retardancy, and is particularly preferably 30% to 50% by mass of the total amount of the curable composition. Furthermore, when the curable composition is used for applications such as conductive paste, which will be detailed below, conductive fillers such as silver powder and copper powder can be used. Furthermore, the silane coupling agent, release agent, pigment, emulsifier, and solvent are not particularly limited, and known ones can be used. Also, as the solvent, organic solvents described herein may be used.

[0081] [Cured product] The cured product of this disclosure is preferably obtained by the curable composition. The cured product can be obtained by curing the curable composition. The curable composition can be obtained by uniformly mixing the above-mentioned components (e.g., curing agent, compounding agent) and can be easily cured in the same manner as conventionally known methods. Examples of the cured product include molded cured products such as laminates, cast products, adhesive layers, coatings, and films. The aforementioned curing (thermosetting) reaction can be easily carried out without a catalyst, but if a faster reaction is desired, the addition of polymerization initiators such as organic peroxides and azo compounds, or basic catalysts such as phosphine compounds and tertiary amines is effective. Examples include benzoyl peroxide, dicumyl peroxide, azobisisobutyronitrile, triphenylphosphine, triethylamine, and imidazoles, and the amount added is preferably 0.05 to 5% by mass of the total curable composition.

[0082] (Heat-resistant materials and electronic materials) The cured product obtained from the curable composition of this disclosure exhibits low hygroscopicity and excellent heat resistance and dielectric properties, making it suitable for use in heat-resistant members or electronic components. In particular, it is suitable for use in prepregs, circuit boards, semiconductor encapsulation materials, semiconductor devices, build-up films, build-up substrates, adhesives and resist materials using conductive pastes, etc. It can also be suitable for use as a matrix resin for fiber-reinforced resins, and is especially suitable as a high-heat-resistant prepreg. Furthermore, the maleimide compound contained in the curable composition exhibits excellent solubility in various solvents, making it possible to manufacture paints. The heat-resistant members and electronic components thus obtained can be suitably used in a variety of applications, including, but are not limited to, industrial machine parts, general machine parts, automobile, railway, and vehicle parts, aerospace-related parts, electronic and electrical components, building materials, containers and packaging materials, household goods, sports and leisure goods, wind power generation housing components, etc.

[0083] <Semiconductor encapsulation materials> This disclosure relates to a semiconductor encapsulation material containing the curable composition of this embodiment. The semiconductor encapsulation material obtained using the curable composition of this embodiment has improved heat resistance, low dielectric properties, or coefficient of thermal expansion, and therefore exhibits excellent processability, moldability, and reflow resistance in the manufacturing process, making it a desirable embodiment. The curable composition of this embodiment used in the semiconductor encapsulating material may contain an inorganic filler. The filling ratio of the inorganic filler can be, for example, 0.5 to 1200 parts by mass of the inorganic filler per 100 parts by mass of the curable composition of this embodiment. Examples of the inorganic filler include barium sulfate, barium titanate, amorphous silica, crystalline silica, Neuburg silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, and the like. As for methods to obtain the semiconductor encapsulating material, one method is to thoroughly melt and mix the curable composition of this embodiment with an optional additive until uniform, as needed, using an extruder, needle, roll, etc. When used as a high thermal conductivity semiconductor encapsulating material for power transistors and power ICs, it is preferable to use a high-filling ratio of crystalline silica, alumina, silicon nitride, etc., which have higher thermal conductivity than fused silica, or to use fused silica, crystalline silica, alumina, silicon nitride, etc. The filling ratio is preferably in the range of 30 to 95 parts by mass of inorganic filler per 100 parts by mass of curable composition, and in particular, 70 parts by mass or more is more preferable, and 80 parts by mass or more is even more preferable, in order to improve flame retardancy, moisture resistance, solder crack resistance, and the coefficient of linear expansion.

[0084] <Semiconductor device> This disclosure relates to a semiconductor device comprising a cured product of the semiconductor encapsulating material. A semiconductor device obtained using a semiconductor encapsulating material obtained using the curable composition of this embodiment is preferable because, since it uses a curable composition containing the maleimide compound of this disclosure, it has low viscosity and excellent fluidity, and furthermore, improved heat resistance, low dielectric properties, low coefficient of thermal expansion, or adhesion to metal materials, resulting in excellent processability, moldability, and reflow resistance in the manufacturing process. Methods for obtaining the semiconductor device include casting the semiconductor encapsulating material, molding it using a transfer molding machine, injection molding machine, etc., and then heat-curing it in a temperature range of room temperature (20°C) to 250°C.

[0085] <Prepreg> This disclosure relates to a prepreg having a reinforcing substrate and a semi-cured product of the curable composition of this embodiment impregnated into the reinforcing substrate. A method for obtaining a prepreg from the curable composition includes impregnating a reinforcing substrate (paper, glass cloth, glass nonwoven fabric, aramid paper, aramid cloth, glass mat, glass roving cloth, etc.) with a varnished curable composition made by blending it with an organic solvent, as described later, and then heating it at a heating temperature corresponding to the type of solvent used, preferably 50 to 170°C, to semi-cure (or not cure) the curable composition and obtain a prepreg. The mass ratio of the curable composition to the reinforcing substrate used at this time is not particularly limited, but it is generally preferable to prepare it so that the resin content in the prepreg is 20 to 60% by mass. In this embodiment, a semi-cured product of the curable composition is obtained by adjusting the heating temperature and heating time to stop the curing reaction before it is completed. For example, the semi-cured product may have a degree of curing of 85% or less and 5% or more. On the other hand, the cured product in this embodiment may have a higher degree of curing than the semi-cured product. The degree of hardening of the semi-cured product can be calculated using the following formula by measuring the heat generated during curing of the curable composition and the heat generated during curing of the semi-cured product using DSC. Degree of curing (%) = [1 - (heat generated during curing of the semi-cured material / heat generated during curing of the curable composition)] × 100

[0086] Examples of organic solvents used in the production of prepregs include methyl ethyl ketone, acetone, dimethylformamide, methyl isobutyl ketone, methoxypropanol, cyclohexanone, methyl cellosolve, ethyl diglycol acetate, and propylene glycol monomethyl ether acetate. The selection and appropriate amount of these solvents can be appropriately chosen depending on the application. For example, when further manufacturing printed circuit boards from prepregs as described below, it is preferable to use polar solvents with a boiling point of 160°C or lower, such as methyl ethyl ketone, acetone, and dimethylformamide, and it is also preferable to use them in a proportion that results in a non-volatile content of 40 to 80% by mass.

[0087] <Circuit board> This disclosure relates to a circuit board which is a laminate of the prepreg and copper foil. A method for obtaining a printed circuit board from the curable composition of this embodiment is to laminate the prepreg by a conventional method, add copper foil as appropriate, and heat-press it at 170 to 300°C for 10 minutes to 3 hours under pressure of 1 to 10 MPa.

[0088] <Build-up board> A method for obtaining a build-up substrate from the curable composition of this embodiment is to follow the following steps 1 to 3. In step 1, first, the curable composition, which is appropriately blended with rubber, filler, etc., is applied to a circuit board with a circuit formed on it using a spray coating method, a curtain coating method, etc., and then cured. In step 2, if necessary, holes such as predetermined through-holes are drilled in the circuit board to which the curable composition has been applied, then it is treated with a roughening agent and the surface is washed with hot water to form irregularities on the substrate, and then a metal such as copper is plated onto it. In step 3, the operations of steps 1 to 2 are repeated sequentially as desired to alternately build up a resin insulating layer and a conductor layer of a predetermined circuit pattern to form a build-up substrate. In the above steps, it is preferable to drill the through-holes after the formation of the outermost resin insulating layer. Furthermore, in this embodiment, the build-up substrate can also be manufactured by forming a roughened surface by heating and pressing a resin-coated copper foil, which has the composition semi-cured on a copper foil, onto a wiring board on which a circuit has been formed, at 170 to 300°C, thereby eliminating the plating process.

[0089] <Build-up film> This disclosure relates to a build-up film containing the curable composition of this embodiment. A method for manufacturing the build-up film of this embodiment is to apply the curable composition onto a support film (Y), dry it, and form a layer of the curable composition on the support film (Y) to produce an adhesive film for multilayer printed circuit boards.

[0090] When manufacturing a build-up film from a curable composition, it is essential that the film softens under the lamination temperature conditions of the vacuum lamination method (usually 70-140°C) and exhibits fluidity (resin flow) that allows for resin filling into via holes or through-holes present in the circuit board simultaneously with lamination of the circuit board. It is preferable to formulate the above-mentioned components in such a way as to exhibit these characteristics. Furthermore, the resulting build-up film and circuit board (such as a copper-clad laminate) require uniform appearance to avoid phenomena such as locally differing characteristic values ​​caused by phase separation, and to exhibit consistent performance in any desired area.

[0091] Here, the diameter of the through-holes in a multilayer printed circuit board is typically 0.1 to 0.5 mm, and the depth is typically 0.1 to 1.2 mm. It is generally preferable to be able to fill the holes with resin within this range. When laminating both sides of the circuit board, it is desirable to fill about half of the through-holes.

[0092] The adhesive film described above can be manufactured by first preparing a varnish-like curable composition, then applying this varnish-like composition to the surface of a support film (Y), and finally drying the organic solvent by heating or blowing hot air to form a composition layer (X) made of the curable composition. The organic solvent can preferably be ketones such as acetone, methyl ethyl ketone, and cyclohexanone; acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. It is also preferable to use the solvent in a proportion that results in a non-volatile content of 30 to 60% by mass.

[0093] The thickness of the formed composition layer (X) is usually preferably greater than or equal to the thickness of the conductor layer. Since the thickness of the conductor layer of a circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm.

[0094] Furthermore, the composition layer (X) in this embodiment may be protected by a protective film, which will be described later. By protecting it with a protective film, it is possible to prevent dirt and other debris from adhering to the surface of the resin composition layer and to prevent scratches.

[0095] The support film (Y) and protective film mentioned above can be made of polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate, polycarbonate, polyimide, and also release paper and metal foils such as copper foil and aluminum foil. The support film and protective film may be treated with a mat treatment, corona treatment, or release treatment.

[0096] The thickness of the support film is not particularly limited, but is usually 10 to 150 μm, and preferably in the range of 25 to 50 μm. The thickness of the protective film is preferably 1 to 40 μm.

[0097] The support film (Y) described above is peeled off after lamination to the circuit board or after an insulating layer is formed by heat curing. Peeling off the support film (Y) after heat curing the adhesive film prevents the adhesion of dust and other debris during the curing process. When peeling off after curing, the support film is usually treated with a release agent beforehand. Furthermore, a multilayer printed circuit board can be manufactured from the build-up film obtained as described above. For example, if the resin composition layer (X) is protected by a protective film, these are removed, and then the resin composition layer (X) is laminated to one or both sides of the circuit board so that it is in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be batch or continuous on a roll. If necessary, the build-up film and the circuit board may be heated (preheated) before lamination. The lamination conditions are preferably a pressure temperature (lamination temperature) of 70 to 140°C and a pressure of 1 to 11 kgf / cm². 2 (9.8 × 10 4 ~107.9×10 4 N / m 2 It is preferable to use this method, and it is preferable to laminate under reduced pressure of 20 mmHg (26.7 hPa) or less.

[0098] <Conductive paste> One method for obtaining a conductive paste from the curable composition of this disclosure is to disperse conductive particles in the composition. Depending on the type of conductive particles used, the conductive paste can be a paste resin composition for circuit connection or an anisotropic conductive adhesive. [Examples]

[0099] The present invention will be specifically described by examples and comparative examples, but unless otherwise specified, "parts" and "%" below refer to mass. The physical properties of the synthesized maleimide compounds were measured as follows and are shown in Table 1.

[0100] (1) Amine equivalent and maleimide group equivalent The amine equivalent of intermediate amine compound (1) and the maleimide group equivalent of the maleimide compound were measured using the following measurement method. <Amine equivalent of intermediate amine compound (1)> The amine equivalent of the intermediate amine compound (1) obtained in the example was measured by the following method. One milliequivalent of the intermediate amine compound was weighed into an Erlenmeyer flask and dissolved in 20 ml of MEK. Then, 5 ml of acetic acid was added, followed by an appropriate amount of indicator solution (crystal violet acetic acid solution), and the mixture was titrated with a 0.1 M perchloric acid standard solution (at a temperature of 20°C). A blank test was performed using the same method to correct the result. Amine equivalent (g / equivalent) = 1000 / [[(A - Blank) / S] × 0.1] S: Amount of sample (g) A: Titration volume (mL) of 0.1M perchloric acid standard solution Blank: Titration volume (mL) of 0.1M perchloric acid standard solution in the blank test. <Maleimide group equivalent of maleimide compounds> The maleimide group equivalent of the maleimide compound obtained in the example is calculated from the amine equivalent of the intermediate amine compound (1), and is given by the following formula. Maleimide equivalent (g / equivalent) = Amine equivalent + 80

[0101] (2) GPC measurement The number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the maleimide compounds obtained in the examples and comparative examples were calculated using the following measuring equipment and conditions. "Measuring device" Tosoh Corporation's "HLC-8320 GPC" "Measurement conditions" Column: Guard column "HXL-L" manufactured by Tosoh Corporation + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation + "TSK-GEL G3000HXL" manufactured by Tosoh Corporation + "TSK-GEL G4000HXL" manufactured by Tosoh Corporation Detector: RI (Differential Refractometer) Data processing: Tosoh Corporation's "GPC Workstation EcoSEC-WorkStation" Measurement conditions: Column temperature 40℃ Developing solvent: tetrahydrofuran Flow rate 1.0ml / min Standard: In accordance with the measurement manual for the aforementioned "GPC Workstation EcoSEC-WorkStation," the following monodisperse polystyrenes with known molecular weights were used. (Uses polystyrene) "A-500" manufactured by Tosoh Corporation "A-1000" manufactured by Tosoh Corporation "A-2500" manufactured by Tosoh Corporation "A-5000" manufactured by Tosoh Corporation "F-1" manufactured by Tosoh Corporation "F-2" manufactured by Tosoh Corporation "F-4" manufactured by Tosoh Corporation Tosoh Corporation's "F-10" F-20 manufactured by Tosoh Corporation Tosoh Corporation's "F-40" Tosoh Corporation's "F-80" Tosoh Corporation's "F-128" Sample: A tetrahydrofuran solution of the maleimide compound obtained in the synthesis example, at a concentration of 1.0% by mass (based on resin solids content), filtered through a microfilter (50 μl).

[0102] (3) FD-TOF / MS measurement The FD-MS spectra of the maleimide compounds obtained in the examples and comparative examples were measured using the following measuring equipment and conditions. Measurement equipment: JMS-T2000GC AccuTOF GC-Alpha Solvent: THF

[0103] (4)NMR measurement (4-1) 13 C-NMR measurement Maleimide compounds obtained in the examples 13 The 1C-NMR spectra were measured using the following measuring instrument and under the following conditions. 13 C-NMR: “JNM-ECA500” manufactured by JEOL RESONANCE Resonance frequency: 125MHz Total number of times: 2000 Solvent: Chloroform-d Sample quantity: 300 mg Solvent volume: 0.4 ml Reference substance: TMS (3 drops) Relaxation agent: Chromium(III) acetylacetonate

[0104] (4-2) 1 H-NMR measurement Maleimide compounds obtained in the examples 1 The H-NMR spectrum was measured under the following conditions. 1 H-NMR: “JNM-ECA500” manufactured by JEOL RESONANCE Resonance frequency: 500MHz Total number of times: 16 Solvent: Chloroform-d Sample quantity: 100 mg Solvent volume: 0.5 ml Reference substance: TMS (3 drops)

[0105] (5) Synthesis of maleimide compounds <Example 1> Synthesis of maleimide compound (1) (5-1-1) Synthesis of intermediate amine compound (1.1) In a flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 605.45 g of 2,3-xylidine, 60.06 g of paraformaldehyde, 605.45 g of toluene, and 166.38 g of activated clay were charged. The mixture was heated to 100°C while stirring and held for 1 hour while dehydrating. Then, the mixture was heated to 120°C while distilling off the toluene and held at the same temperature for 2 hours. After holding, the mixture was heated to 190°C and held at the same temperature for 10 hours. After the reaction was complete, the mixture was diluted with 500 g of toluene and the activated clay was filtered off. The filtrate was heated under reduced pressure to remove the solvent and unreacted 2,3-xylidine, yielding the intermediate amine compound (1.1) (amine equivalent 133 g / equivalent). The obtained intermediate amine compound (1.1) had a Mn of 250 and a Mw of 318. Furthermore, the GPC chart for the intermediate amine compound (1.1) is shown in Figure 1.

[0106] (5-1-2) Maleimidization A flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer was charged with 84.55 g (1.15 equivalents) of maleic anhydride and 255.58 g of toluene, and stirred at room temperature (22°C to 30°C) to prepare maleic anhydride solution (1). Next, a mixed solution of 100 g (1 equivalent) of intermediate amine compound (1.1) and 68.57 g of dimethylformamide (DMF) was added dropwise to the maleic anhydride solution (1) over 1 hour, and the reaction was allowed to proceed for 2 hours. Then, 7.13 g of p-toluenesulfonic acid monohydrate was added to this reaction solution, and it was heated to 115°C. After cooling and separating the azeotrope-forming water and toluene under reflux, only the toluene was returned to the system and the dehydration reaction was carried out for 5 hours. After the dehydrated reaction solution was air-cooled to room temperature, it was neutralized with 49% NaOH. Subsequently, toluene and water were removed by vacuum distillation at 60°C, and crystals were precipitated by dropping the remaining DMF solution in the flask into a large amount of water. After filtering off the crystals, they were washed twice with pure water and dried to obtain a yellow maleimide compound (1). The number-average molecular weight (Mn) of this maleimide compound (1) was 495, and the weight-average molecular weight (Mw) was 556. The GPC chart of maleimide compound (1) is shown in Figure 2. 13 Figure 3 shows the 1C NMR chart, and Figure 4 shows the FD-TOF / MS results for maleimide compound (1). 1 The 1H-NMR chart is shown in Figure 5. The maleimide equivalent (g / equivalent) of maleimide compound (1) was 213.

[0107] <Example 2> Synthesis of Maleimide Compound (2) (5-2-1) Synthesis of intermediate amine compound (2.1) In a flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer, 605.45 g of 2,5-xylidine, 60.06 g of paraformaldehyde, 605.45 g of toluene, and 166.38 g of activated clay were charged. The mixture was heated to 100°C while stirring and held for 1 hour while dehydrating. Then, the mixture was heated to 120°C while distilling off the toluene and held at the same temperature for 2 hours. After holding, the mixture was heated to 190°C and held at the same temperature for 10 hours. After the reaction was complete, the mixture was diluted with 500 g of toluene and the activated clay was filtered off. The filtrate was heated under reduced pressure to remove the solvent and unreacted 2,5-xylidine, yielding the intermediate amine compound (2.1) (amine equivalent 132 g / equivalent). The obtained intermediate amine compound (2.1) had a Mn of 241 and a Mw of 305. The GPC chart for intermediate amine compound (2.1) is shown in Figure 6.

[0108] (5-2-2) Maleimidization A flask equipped with a thermometer, condenser, Dean-Stark trap, and stirrer was charged with 85.43 g (1.15 equivalents) of maleic anhydride and 256.85 g of toluene, and stirred at room temperature (22°C to 30°C) to prepare maleic anhydride solution (1). Next, a mixed solution of 100 g (1 equivalent) of intermediate amine compound (1.2) and 68.83 g of dimethylformamide (DMF) was added dropwise to the maleic anhydride solution (1) over 1 hour, and the reaction was allowed to proceed for 2 hours. Then, 7.21 g of p-toluenesulfonic acid monohydrate was added to this reaction solution, and it was heated to 115°C. After cooling and separating the azeotrope-forming water and toluene under reflux, only the toluene was returned to the system and the dehydration reaction was carried out for 5 hours. After the dehydrated reaction solution was air-cooled to room temperature, it was neutralized with 49% NaOH. Subsequently, toluene and water were removed by vacuum distillation at 60°C, and crystals were precipitated by dropping the remaining DMF solution in the flask into a large amount of water. After filtering off the crystals, they were washed twice with pure water and dried to obtain a yellow maleimide compound (2). The number-average molecular weight (Mn) of this maleimide compound (2) was 441, and the weight-average molecular weight (Mw) was 508. Figure 7 shows the GPC chart for maleimide compound (2). 13Figure 8 shows the 1C-NMR chart, and Figure 9 shows the FD-TOF / MS results for maleimide compound (2). 1 The 1H-NMR chart is shown in Figure 10. The maleimide equivalent (g / equivalent) of maleimide compound (2) was 212.

[0109] (6) Preparation of curable composition and production of cured product <Example 3> Preparation of curable composition (1) The maleimide compound (1) obtained in Example 1 above and DCPO ("Perkmyl D", NOF Corporation, Dicumyl Peroxode) as a catalyst were blended in the proportions shown in Table 1 below to prepare the curable composition of Example 3. <Example 4> Preparation of curable composition (2) The maleimide compound (2) obtained in Example 2 above and DCPO ("Perkmyl D", NOF Corporation, Dicumyl Peroxode) as a catalyst were blended in the proportions shown in Table 1 below to prepare the curable composition of Example 4.

[0110] <Comparative Example 1> Preparation of comparative curable composition (1) Comparative curable composition (1) for Comparative Example 1 was prepared by blending comparative maleimide (1) represented by the following formula (5) ("BMI-5100," manufactured by Yamato Chemical Industries, Ltd.) and DCPO ("Parkmill D," NOF Corporation, Dicumyl Peroxode) as a catalyst in the proportions shown in Table 1 below. [ka]

[0111] <Comparative Example 2> Preparation of comparative curable composition (2) Comparative maleimide (2) represented by the following formula (6) ("BMI-2300," manufactured by Yamato Chemical Industries, Ltd.) and DCPO ("Parkmill D," NOF Corporation, Dicumyl Peroxode) as a catalyst were blended in the proportions shown in Table 1 below to prepare comparative example 2 curable composition (2). [ka]

[0112] Next, cured products corresponding to the curable compositions of Examples 3 and 4 and the comparative curable compositions of Comparative Examples 1 and 2 were prepared by curing them under the following curing conditions. Then, the physical properties of dielectric loss tangent, heat resistance, and thermal expansion coefficient were evaluated using the method described below. The results are shown in Table 1. <<Curing conditions>> Using a vacuum press, the material is heated and cured at 200°C for 2 hours, followed by 250°C for 2 hours. Thickness after molding: 1.3mm <<Measurement of Dielectric Loss Tangent>> In accordance with JIS-C-6481, the dielectric loss tangent at 10 GHz was measured using the cavity resonance method with an Agilent Technologies, Inc. network analyzer "E8362C" after complete drying and storage in a room at 23°C and 50% humidity for 24 hours. A dielectric loss tangent value of 0.0025 or less is considered good. <<Measurement of thermal expansion coefficient>> Test specimens cut from the hardened material obtained above to dimensions of 5 mm × 5 mm × 1.3 mm were subjected to thermomechanical analysis in compression mode using a thermomechanical analyzer (TMA: Seiko Instruments SS-6100) under the following conditions. Measurement load: 88.8 mN Heating rate: 3°C / min Measurement temperature range: -50°C to 288°C The same sample was measured twice under the conditions described below. The average linear expansion coefficient in the temperature range of 30°C to 100°C during the second measurement was calculated to determine the thermal expansion characteristics. A thermal expansion coefficient of 40 ppm or less was considered good.

[0113] [Table 1]

[0114] From the results shown in Table 1 above, a comparison of Examples 3 and 4 with Comparative Examples 1 and 2 confirmed that by using the maleimide compounds (1) and (2) of the examples, a cured product possessing excellent dielectric properties, high heat resistance, and low thermal expansion was obtained. [Industrial applicability]

[0115] According to the present invention, it is possible to provide a maleimide compound that exhibits excellent dielectric properties, high heat resistance, and low thermal expansion during curing, a curable composition containing the maleimide compound, and a cured product thereof.

Claims

1. A maleimide compound having two or more aromatic maleimide compound structural units (A), each having one to two substituents at the meta position of an aromatic ring, linked by methylene groups.

2. The aromatic maleimide compound structural unit (A1) is represented by the following general formula (I-1), The methylene group represented by the following general formula (I-2) and The maleimide compound according to claim 1, having an aromatic maleimide compound structural unit (A2) represented by the following general formula (I-3). 【Chemistry 1】 (In the above general formula (I-1), L １ This represents a bond, which is chemically bonded to one of the bonds of the methylene group represented by the general formula (I-2) above. R １１ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group represented by general formula (I-2) bonded to one of its bonds. R １２ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2). X １１ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n1 represents an integer between 0 and 3, n² represents an integer between 0 and 3, However, in the above general formula (I-1), R １１ and R １２ At least one of them is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as the substituent. (In the above general formula (I-3), L ２ This represents a bond, which is chemically bonded to one of the bonds of the methylene group represented by the general formula (I-2) above. R １３ Each of these independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonds of a group represented by general formula (I-2). R １４ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group bonded to one of the bonding hands of the group represented by the general formula (I-2). X １２ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. n3 represents an integer between 0 and 3, n4 represents an integer between 0 and 3, However, in the above general formula (I-3), R １３ and R １４ At least one of them is an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms as the substituent.

3. The maleimide compound according to claim 1, having a substructure represented by the following general formula (1). 【Chemistry 2】 (In the above general formula (1), R １ and R ２ Each of these independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. X １ and X ２ Each of these independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyl group, an amino group, or a cyano group. ni represents an integer between 0 and 2, nii represents an integer between 0 and 2, k represents the degree of polymerization. Note that in the general formula (1) above, * represents a bond with another atom.

4. A maleimide compound is reacted using an aromatic amine compound having one to two substituents at the meta position of an aromatic ring, formaldehydes, and maleic anhydride as reaction raw materials (1).

5. A curable composition containing the maleimide compound according to any one of claims 1 to 4.

6. A cured product of the curable composition according to claim 5.

7. A prepreg having a reinforcing substrate and a semi-cured product of the curable composition according to claim 5 impregnated into the reinforcing substrate.

8. A circuit board formed by laminating the prepreg and copper foil according to claim 7 and then heat-pressing them together.

9. A build-up film containing the curable composition described in claim 5.

10. A semiconductor encapsulant containing the curable composition described in claim 5.

11. A semiconductor device comprising a cured product of the semiconductor encapsulant according to claim 10.

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