Thermosetting bismaleimide resin composition

Abstract

To provide a resin composition that yields a cured product with a high glass transition temperature and superior dielectric properties.SOLUTION: A thermosetting bismaleimide resin composition includes (A) a bismaleimide compound having a structure represented by the formula (1) (where A's independently represent a C4-200 tetravalent organic group, B's independently represent a C2-200 divalent organic group, and n represents 2-100), with the A and / or B having a fluorene skeleton, and (B) a reaction promoter.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a thermosetting bismaleimide resin composition, an uncured resin film, a cured resin film, a prepreg, a substrate, an adhesive, and a semiconductor encapsulant using the same.

Background Art

[0002] In recent years, miniaturization and high performance of electronic devices have advanced, and in multilayer printed wiring boards, miniaturization and high density of wiring have been demanded. Furthermore, in the next generation, materials for high-frequency bands are required, and since reduction of transmission loss is essential as a noise countermeasure, development of insulating materials with excellent dielectric properties has been demanded.

[0003] As insulating materials for multilayer printed wiring boards, epoxy resin compositions containing epoxy resins, specific phenolic curing agents, phenoxy resins, rubber particles, and polyvinyl acetal resins disclosed in Patent Documents 1 and 2 are known, but these materials have been found not to satisfy high-frequency band applications represented by the keyword 5G. On the other hand, in Patent Document 3, it is reported that an epoxy resin composition containing an epoxy resin, an active ester compound, and a triazine-containing cresol novolak resin is effective for reducing the dielectric tangent, but even this material requires lower dielectric properties for high-frequency applications.

[0004] On the other hand, in Patent Document 4, it is reported that a resin film composed of a resin composition containing a bismaleimide resin having a long-chain alkyl group and a curing agent as a non-epoxy-based material has excellent dielectric properties, but it is substantially a combination of a bismaleimide resin having a long-chain alkyl group and a hard low-molecular aromatic maleimide, and it is very difficult to achieve a high glass transition temperature (Tg) of 100°C or higher required for substrate applications.

[0005] In addition, Patent Document 5 proposes a fluorene-containing imide oligomer as a heat-resistant plasticizer. However, since this oligomer does not have thermosetting properties, there are still problems with handling properties in substrate applications. Patent Document 6 discloses a thermosetting polyimide having a fluorene skeleton. However, since this resin has an allyl group as a thermosetting functional group, the curing is insufficient, there is a limit to the glass transition temperature, and the heat resistance is insufficient.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, an object of the present invention is to provide a thermosetting resin composition having low relative permittivity and dielectric loss tangent at high frequencies, excellent dielectric properties, and excellent heat resistance.

Means for Solving the Problems

[0008] As a result of intensive studies to solve the above problems, the present inventors have found that the following thermosetting fluorene-containing bismaleimide resin composition can achieve the above object, and have completed the present invention.

[0009] <1> (A) The following formula (1) [Chemical formula] (In formula (1), A independently represents a tetravalent organic group having 4 to 200 carbon atoms. B independently represents a divalent organic group having 2 to 200 carbon atoms. n is 2 to 100.) represented by In said A and / or B, the following formula (2) [Chemical formula] (In formula (2), R 1 , R 2 , R 3 and R 4 are independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a (hetero)aryl group having 4 to 10 carbon atoms, a hydroxyl group, an alkoxy group, a halogeno group, an amino group or a sulfenyl group.) a bismaleimide compound having a fluorene skeleton represented by, and (B) a reaction accelerator a thermosetting bismaleimide resin composition containing <2> The thermosetting bismaleimide resin composition according to <1>, wherein the reaction accelerator of component (B) is a radical polymerization initiator or an anionic polymerization initiator containing at least one of a nitrogen atom and a phosphorus atom. <3> The thermosetting bismaleimide resin composition according to <1> or <2>, wherein the glass transition temperature of the cured product is 200 °C or higher. <4> An uncured resin film comprising the thermosetting bismaleimide resin composition according to any one of <1> to <3>. <5> A cured resin film comprising a cured product of the thermosetting bismaleimide resin composition according to any one of <1> to <3>. <6> A prepreg having the thermosetting bismaleimide resin composition according to any one of <1> to <3> and a fiber base material. <7> A substrate containing the thermosetting bismaleimide resin composition according to any one of <1> to <3>. <8> An adhesive comprising the thermosetting bismaleimide resin composition according to any one of <1> to <3>. <9> A semiconductor encapsulant comprising the thermosetting bismaleimide resin composition according to any one of <1> to <3>.

Advantages of the Invention

[0010] In the case of the thermosetting bismaleimide resin composition of the present invention, compared with a bismaleimide resin composition having no fluorene skeleton, when formed into a film shape or a substrate shape, the glass transition temperature can be further increased while maintaining excellent dielectric properties.

Modes for Carrying Out the Invention

[0011] The present invention will be described in detail below.

[0012] (A) Bismaleimide compound having a fluorene skeleton The component (A) used in the present invention is a bismaleimide compound represented by the following formula (1), and A and / or B has a fluorene skeleton represented by the following formula (2). The bismaleimide compound of the component (A) has a fluorene skeleton in the molecule, so that the cured product of the composition containing this has excellent heat resistance.

Chemical formula

Chemical formula

[0013] The fluorene skeleton represented by the formula (2) may be possessed by one of A and B in the formula (1), or may be possessed by both A and B. R in the formula (2) 1 , R 2 , R 3 and R 4 Examples of the alkyl group having 1 to 5 carbon atoms for R , R , R and R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, and a pentyl group. R in the formula (2) 1 , R 2 , R 3 and R 4 Examples of the (hetero)aryl group having 4 to 10 carbon atoms represented by R , R , R and R include aryl groups having 6 to 10 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group, and heteroaryl groups having 4 to 10 carbon atoms such as a furyl group, a thienyl group, a pyridyl group, and an indolyl group. R in the formula (2) 1 , R 2 , R 3 and R 4 Examples of the alkoxy group represented by R , R , R and R include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a t-butyloxy group, an n-pentyloxy group, an isopentyloxy group, a hexyloxy group, a benzyloxy group, a phenethyloxy group, an allyloxy group, a phenyloxy group, a tolyloxy group, a xylyloxy group, a naphthyloxy group, a furyloxy group, a thienyloxy group, a pyridyloxy group, an indolyloxy group, and the like. R in the formula (2) 1 , R 2 , R 3 and R 4 Examples of the halogeno group represented by R , R , R and R include a fluoro group, a chloro group, a bromo group, an iodo group, and the like.

[0014] In the formula (1), A is independently a tetravalent organic group having 4 to 200 carbon atoms, preferably 4 to 100 carbon atoms, more preferably 4 to 50 carbon atoms. Further, A is preferably an organic group having an aromatic ring or an alicyclic structure.

[0015] When B in the formula (1) is a group having a fluorene skeleton, A in the formula (1) may be a group having a fluorene skeleton or a group not having a fluorene skeleton. When B in the formula (1) is a group not having a fluorene skeleton, A in the formula (1) is a group having at least one fluorene skeleton.

[0016] Among As in the formula (1), examples of the group not having a fluorene skeleton are exemplified by the following structural formulas.

Chemical formula

Chemical formula

[0017] Among As in the formula (1), examples of the group having a fluorene skeleton are exemplified by the following structural formulas.

Chemical formula

Chemical formula

[0018] Note that A in the formula (1) may be of one kind or a plurality of kinds.

[0019] In the formula (1), B is independently a divalent organic group having 2 to 200 carbon atoms, preferably 2 to 100 carbon atoms, more preferably 2 to 50 carbon atoms.

[0020] When A in the formula (1) is a group having a fluorene skeleton, B in the formula (1) may be a group having a fluorene skeleton or a group not having a fluorene skeleton. When A in the formula (1) is a group not having a fluorene skeleton, B in the formula (1) is a group having at least one fluorene skeleton.

[0021] Among B in the formula (1), examples of the group having no fluorene skeleton include 1,10-diaminodecane, 1,12-diaminododecane, dimer diamine, 1,2-diamino-2-methylpropane, 1,2-diaminocyclohexane, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,7-diaminoheptane, 1,8-diaminomenthane, 1,8-diaminooctane, 1,9-diaminononane, 3,3'-diamino-N-methyldipropylamine, diaminomaleonitrile, 1,3-diaminopentane, 9,10-diaminophenanthrene, 4,4'-diaminooctafluorobiphenyl, 3,5-diaminobenzoic acid, 4,4'-diaminobenzophenone, 3,4-diaminobenzophenone, 3,4-diaminotoluene, 2,6-diaminoanthraquinone, 2,6-diaminotoluene, 2,3-diaminotoluene, 1,8-diaminonaphthalene, 2,4-diaminotoluene, 2,5-diaminotoluene, 1,4-diaminoanthraquinone, 1,5-diaminoanthraquinone, 1,5-diaminonaphthalene, 1,2-diaminoanthraquinone, 2,4-cumenediamine, 1,3-bis(aminomethyl)benzene (m-xylylenediamine), 1,4-bis(aminomethyl)benzene (p-xylylenediamine), 1,3-bis(aminomethyl)cyclohexane, 2-chloro-1,4-diaminobenzene, 1,4-diamino-2,5-dichlorobenzene, 1,4-diamino-2,5-dimethylbenzene, 4,4'-diamino-2,2'-bistrifluoromethylbiphenyl, 1,2-bis(4-amino-3-chlorophenyl)ethane, bis(4-amino-3,5-dimethylphenyl)methane, bis(4-amino-3,5-diethylphenyl)methane, 3,4-diaminobenzoic acid, 2,3-diaminonaphthalene, 2,3-diaminophenol, bis(4-amino-3-methylphenyl)methane, bis(4-amino-3-ethylphenyl)methane, 4,4'-diaminophenyl sulfone, 3,3'-diaminophenyl sulfone, bis(4-(4-aminophenoxy)phenyl) sulfone, bis(4-(3-aminophenoxy)phenyl) sulfone, 4,4'-oxydianiline, 4,4'-diaminodiphenyl sulfide, 3,4'-oxydianiline, 2,2-Bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-diamino-3,3'-dihydroxybiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-dimethoxybiphenyl, bisaniline M (1,3-bis[2-(4-aminophenyl)-2-propyl]benzene), bisaniline P (1,4-bis[2-(4-aminophenyl)-2-propyl]benzene), o-tolidine sulfone, methylene bis(anthranilic acid), 1,3-bis(4-aminophenoxy)-2,2-dimethylpropane, 1,3-bis(4-aminophenoxy)propane, 1,4-bis(4-aminophenoxy)butane, 1,5-bis(4-aminophenoxy)pentane, 2,3,5,6-tetramethyl-1,4-phenylenediamine, 3,3',5,5'-tetramethylbenzidine, 4,4'-diaminobenzanilide, 2,2-bis(4-aminophenyl)hexafluoropropane, polyoxyalkylene diamines (e.g., JEFFAMINE® D-230, D-400, D-2000, and D-4000 manufactured by Huntsman Corporation), bis(4-amino-3-methylcyclohexyl)methane, 1,2-bis(2-aminoethoxy)ethane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0(2,6)]decane, etc., divalent organic groups obtained by removing two amino groups from diamines. Further, from the viewpoint of enhancing heat resistance, the divalent organic group B having 2 to 200 carbon atoms is preferably a divalent organic group having an aromatic ring or an alicyclic structure. For example, divalent organic groups represented by the following structural formulas, etc., can be mentioned., [Chemical formula] (R 5 , R 6 , R 7 and R 8 are independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a methoxy group, a fluoro group, a chloro group, a bromo group, or a trifluoromethyl group. Z is independently the following formula [Chemical formula] It is a divalent organic group selected from the above. Here, a is a number from 0 to 6.)

[0022] Among B in the formula (1), examples of the group having a fluorene skeleton are exemplified by the following structural formulae.) [Chemical formula] [Chemical formula] (In the above structural formula, the bond to which the substituent is not bonded is bonded to the nitrogen atom forming the cyclic imide structure in the formula (1).)

[0023] In the formula (1), B may be of one kind or a plurality of kinds.)

[0024] In the formula (1), n is 2 to 100, preferably 2 to 80, more preferably 2 to 50.)

[0025] (The bismaleimide compound having a fluorene skeleton in the component (A) has no particular limitation on its properties and number average molecular weight at room temperature, but preferably has a number average molecular weight of 3,000 to 50,000, more preferably 5,000 to 50,000, and still more preferably 8,000 to 50,000. If the number average molecular weight is within this range, the viscosity when the compound is blended into the resin composition does not become too high, and further, the cured product of the resin composition has high strength, which is preferable. In this specification, the number average molecular weight (Mn) is the number average molecular weight converted by polystyrene standard by gel permeation chromatography (GPC) measurement using the following measurement conditions.)

[0026] [GPC measurement conditions] Developing solvent: Tetrahydrofuran (THF) Flow rate: 0.35 mL / min Detector: Differential refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperHZ4000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ3000 (4.6 mm I.D. × 15 cm × 1) TSKgel SuperHZ2000 (4.6 mm I.D. × 15 cm × 2) (All are manufactured by Tosoh Corporation) Column temperature: 40 °C Sample injection volume: 5 μL (THF solution with a concentration of 0.2 mass%)

[0027] (A) Regarding the production method of the component, there are no particular limitations. For example, it can be efficiently produced by changing the starting diamine compound according to the method described in JP-A-2022-77847

[0028] (B) Reaction accelerator The component (B) used in the present invention is a reaction accelerator. The reaction accelerator, which is the component (B) used in the present invention, is added to initiate and accelerate the radical polymerization or anionic polymerization reaction of the bismaleimide compound having a fluorene skeleton as the component (A). (B) The component is not particularly limited as long as it promotes this reaction. However, from the viewpoint of the reaction mechanism, it is preferable to use a radical polymerization initiator catalyst such as an organic peroxide or an anionic polymerization initiator catalyst containing one or more of a nitrogen atom and a phosphorus atom.

[0029] Examples of the radical polymerization initiator include dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide, and the like.

[0030] Examples of the anionic polymerization initiator include ionic catalysts such as imidazoles (e.g., 2-ethyl-4-methylimidazole), tertiary amines, quaternary ammonium salts, boron trifluoride amine complexes, organophosphines (e.g., triphenylphosphine), and organophosphonium salts.

[0031] The reaction accelerator as component (B) may be used alone or in combination of two or more.

[0032] The reaction accelerator as component (B) is preferably blended in the range of 0.01 to 10 parts by mass, particularly 0.1 to 5 parts by mass, based on 100 parts by mass of component (A). If the amount of component (B) is more than this range, unreacted component (B) may remain, which may deteriorate the dielectric properties. On the contrary, if the amount of component (B) is less than the above range, curing may not proceed sufficiently, and there is a concern about a decrease in dielectric properties and heat resistance. In addition, if the blending amount of component (B) is outside the above range, the curing may become extremely slow or fast during the molding of the thermosetting bismaleimide resin composition, which is not preferable, and the balance of heat resistance and moisture resistance of the obtained cured product may also deteriorate.

[0033] The blending amount of component (A) in the thermosetting bismaleimide resin composition of the present invention is preferably 5 to 99.99% by mass, more preferably 10 to 99.9% by mass, based on the total mass of the composition. Since the thermosetting bismaleimide resin composition of the present invention contains component (A) having a robust fluorene skeleton, the glass transition temperature of the cured product is 200°C or higher, preferably 210°C or higher.

[0034] Other additives In the thermosetting fluorene-containing bismaleimide resin composition of the present invention, various additives can be further blended as necessary within a range that does not impair the effects of the present invention. Other additives are exemplified below.

[0035] Thermosetting resin having a reactive group capable of reacting with a maleimide group In the present invention, a thermosetting resin having a reactive group capable of reacting with a maleimide group may be further added. Examples of the reactive group capable of reacting with a maleimide group include an epoxy group, a hydroxyl group, an amino group, an alkenyl group such as an allyl group or a vinyl group, a (meth)acrylic group, a thiol group, and the like. The type of the thermosetting resin having the reactive group is not limited. For example, various resins such as maleimide resins other than component (A), epoxy resins, phenol resins, melamine resins, urea resins, silicone resins, modified polyphenylene ether resins, thermosetting acrylic resins, and polyfunctional thiols can be mentioned. The thermosetting resin having a reactive group capable of reacting with the added maleimide group may be one type or a plurality of types.

[0036] The blending amount of the thermosetting resin having a reactive group capable of reacting with a maleimide group is 0 to 30% by mass, preferably 0 to 20% by mass, in the total of component (A) and the thermosetting resin having a reactive group capable of reacting with a maleimide group.

[0037] Inorganic filler In the present invention, an inorganic filler may be further added as needed. The inorganic filler is compounded for the purpose of enhancing the strength and rigidity of the cured product of the thermosetting fluorene-containing bismaleimide resin composition of the present invention, or adjusting the coefficient of thermal expansion and the dimensional stability of the cured product. As the inorganic filler, those usually compounded in an epoxy resin composition or a silicone resin composition can be used. For example, silicas such as spherical silica, fused silica and crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, barium sulfate, talc, clay, aluminum hydroxide, magnesium hydroxide, calcium carbonate, glass fiber and glass particles, etc. may be mentioned. Further, a fluorine-containing resin, a coating filler, and / or hollow particles may be used to improve dielectric properties, and conductive fillers such as metal particles, metal-coated inorganic particles, carbon fiber, carbon nanotube, etc. may be added for the purpose of imparting conductivity. The inorganic filler to be added may be of one kind or a plurality of kinds.

[0038] The average particle diameter and shape of the inorganic filler are not particularly limited, but spherical silica with an average particle diameter of 0.5 to 5 μm is preferably used particularly when molding an underfill material, a film or a substrate. For adhesive and semiconductor encapsulant applications, spherical silica with an average particle diameter of 3 to 45 μm is preferably used. The average particle diameter is a value determined as the mass average value D 50 (or median diameter) in the particle size distribution measurement by the laser light diffraction method.

[0039] The compounding amount of the inorganic filler is not particularly limited, but it is preferably 5 to 3,000 parts by mass, more preferably 10 to 2,500 parts by mass, and still more preferably 50 to 2,000 parts by mass with respect to 100 parts by mass of the component (A). Within this range, the function of the inorganic particles can be sufficiently exerted while maintaining the strength of the resin composition.

[0040] Furthermore, in order to improve the properties, the inorganic filler is preferably surface-treated with a silane coupling agent having an organic group capable of reacting with a maleimide group. Examples of such silane coupling agents include epoxy group-containing alkoxysilanes, amino group-containing alkoxysilanes, (meth)acrylic group-containing alkoxysilanes, and alkenyl group-containing alkoxysilanes. As the silane coupling agent, (meth)acrylic group and / or amino group-containing alkoxysilanes are preferably used. Specifically, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, etc. can be mentioned.

[0041] Others In addition to the above, non-functional silicone oil, thermoplastic resin, thermoplastic elastomer, synthetic organic rubber, photosensitizer, light stabilizer, polymerization inhibitor, flame retardant, pigment, dye, adhesion aid, etc. may be blended, or an ion trap agent, etc. may be blended to improve electrical properties.

[0042] [Manufacturing method] The manufacturing method of the resin composition of the present invention includes adding component (A), component (B), and other additives as required, and examples thereof include a method of mixing using a planetary mixer or a stirrer. The thermosetting bismaleimide resin composition of the present invention can also be dissolved in an organic solvent and treated as a varnish. By forming a varnish, it becomes easier to form a film, and it also becomes easier to coat and impregnate a glass cloth made of E glass, low dielectric glass, quartz glass, etc., and it becomes easier to manufacture a prepreg. Regarding the organic solvent, any solvent in which component (A) is soluble can be used without limitation.

[0043] The thermosetting bismaleimide resin composition of the present invention can be obtained by applying the above varnish to a substrate, removing the solvent to form an uncured resin sheet or film, and further curing it to form a cured resin sheet or film. The manufacturing methods of sheets and films are exemplified below, but are not limited thereto.

[0044] For example, after applying a thermosetting bismaleimide resin composition dissolved in an organic solvent to a substrate, heating at a temperature of usually 80 °C or higher, preferably 100 °C or higher for 0.5 to 5 hours removes the organic solvent, and further heating at a temperature of 130 °C or higher, preferably 150 °C or higher for 0.5 to 10 hours can form a flat and strong maleimide resin cured film on the surface. The temperature in the drying process for removing the organic solvent and the subsequent heat curing process may each be constant, but it is preferable to raise the temperature step by step. This can efficiently remove the organic solvent outside the composition and efficiently advance the curing reaction of the resin. Examples of the coating method include a spin coater, a slit coater, a spray, a dip coater, a bar coater, etc., but there is no particular limitation.

[0045] As the substrate, those generally used may be used. For example, polyolefin resins such as polyethylene (PE) resin, polypropylene (PP) resin, and polystyrene (PS) resin, and polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polycarbonate (PC) resin can be mentioned, and the surface of this may be subjected to a release treatment. Also, the thickness of the coating layer is not particularly limited, but the thickness after solvent evaporation is in the range of 1 to 100 μm, preferably 3 to 80 μm. Further, a cover film may be used on the coating layer.

[0046] Alternatively, each component may be premixed in advance and extruded into a sheet or film shape using a melt kneader to produce an uncured resin film (uncured resin sheet) or a cured resin film (cured resin sheet).

[0047] When the thermosetting bismaleimide resin composition of the present invention is used as a semiconductor encapsulant, the components (A) and (B) and other components as required are blended at a predetermined composition ratio, and after being sufficiently and uniformly mixed by a mixer or the like, melt mixing is performed using a hot roll, kneader, extruder, etc., and then cooled and solidified, and then pulverized to an appropriate size. The obtained resin composition can be used as an encapsulating material. When the thermosetting bismaleimide resin composition of the present invention is used as an adhesive, the components (A) and (B) and other components as required are blended at a predetermined composition ratio, and after mixing using a mixer such as a planetary mixer, a three-roll mill is used for kneading and mixing as required to enhance dispersibility. The obtained resin composition can be used as an adhesive.

[0048] As a general molding method using a semiconductor encapsulant, a transfer molding method and a compression molding method can be mentioned. In the transfer molding method, using a transfer molding machine, the molding pressure is 5 to 20 N / mm 2 , and the molding is performed at a molding temperature of 120 to 190 °C for a molding time of 30 to 500 seconds, preferably at a molding temperature of 150 to 185 °C for a molding time of 30 to 180 seconds. In the compression molding method, using a compression molding machine, the molding temperature is 120 to 190 °C for a molding time of 30 to 600 seconds, preferably at a molding temperature of 130 to 160 °C for a molding time of 120 to 300 seconds. Further, in any molding method, post-curing may be performed at 150 to 225 °C for 0.5 to 20 hours.

[0049] [Prepreg] The prepreg according to an embodiment of the present invention includes the thermosetting bismaleimide resin composition of the present invention and a fiber base material. The thermosetting bismaleimide resin composition in the prepreg may be a semi-cured product of the resin composition. Note that the semi-cured product is a state in which the resin composition is cured halfway to such an extent that it can be further cured. That is, the semi-cured product is a state in which the resin composition is semi-cured, so-called B-staged. On the other hand, the uncured state is sometimes referred to as the A-stage. As described above, the fiber base material includes E glass, low dielectric glass, quartz glass, and further S glass, T glass, etc. Regardless of the type of glass used, from the viewpoint of taking advantage of the characteristics of the thermosetting maleimide resin composition of the present invention, quartz glass cloth with a low relative permittivity and dielectric tangent is preferred. In addition, the thickness of the generally used fiber base material is, for example, 0.01 mm or more and 0.3 mm or less. When manufacturing the prepreg, in order to impregnate the fiber base material which is the base material for forming the prepreg, the thermosetting bismaleimide resin composition is preferably made into a resin varnish in the form of a varnish. Such a varnish-like resin composition (resin varnish) is prepared, for example, as follows. First, each component that can be dissolved in the organic solvent among the components of the resin composition is added to the organic solvent and dissolved. At this time, heating may be performed as necessary. Then, components that are not dissolved in the organic solvent, such as inorganic fillers, which are used as necessary, are added, and the resin composition in the form of a varnish (resin varnish) is prepared by dispersing it using a ball mill, bead mill, planetary mixer, roll mill, etc. until it reaches a predetermined dispersed state. The organic solvent used here is not particularly limited as long as it does not inhibit the curing reaction. Specifically, for example, toluene, methyl ethyl ketone (MEK), xylene, and anisole are mentioned. Subsequently, after impregnating the fiber base material with the varnish-like resin composition (resin varnish) by dipping and coating, etc., it is dried. It is also possible to repeat the impregnation a plurality of times as necessary. In addition, at this time, by repeating the impregnation using a plurality of resin compositions with different compositions and concentrations, it is also possible to finally adjust to the desired composition and impregnation amount. The fiber base material impregnated with the resin composition (resin varnish) is heated under desired heating conditions, for example, at 80°C or more and 400°C or less for 1 minute or more and 2 hours or less. By heating, a prepreg provided with a thermosetting bismaleimide resin composition in a pre-cured (A stage) or semi-cured state (B stage) is obtained. [Substrate] The prepreg and copper foil may be overlapped and pressed and heat-cured for use as a substrate. The method for manufacturing the substrate is not particularly limited. For example, it can be manufactured by using 1 to 20 sheets, preferably 2 to 10 sheets of the prepreg, arranging copper foils on one or both sides thereof, pressing, and then heating and curing. The thickness of the copper foil is not particularly limited, but is preferably 3 to 70 μm, more preferably 10 to 50 μm, and still more preferably 15 to 40 μm. Within this range, a multilayer substrate with high reliability can be formed. The forming conditions of the substrate are not particularly limited. For example, multi-stage pressing, multi-stage vacuum pressing, continuous forming, an autoclave molding machine, etc. can be used, and it can be formed within the range of a temperature of 100 to 400 °C, a pressure of 1 to 100 MPa, and a heating time of 0.1 to 4 hours. Also, the substrate can be formed by combining the prepreg, copper foil, and inner layer wiring board of the present invention.

Examples

[0050] Hereinafter, examples and comparative examples will be shown to specifically explain the present invention, but the present invention is not limited to the following examples. In the examples and comparative examples, "room temperature" means 25 °C.

[0051] [Example 1] (Production of Bismaleimide Compound 1, Reaction Formula 1) Into a 500 mL three-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser, and a thermometer, 27.96 g (52.5 mmol) of 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, 32.13 g (50.0 mmol) of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride, and 137 g of anisole were added, and the mixture was stirred at 70 °C for 2 hours to synthesize an amic acid. Then, the temperature was directly raised to 150 °C, and the mixture was stirred for 5 hours while distilling off the by-produced water to synthesize a polyimide compound. Subsequently, 0.54 g (5.5 mmol) of maleic anhydride was added to a flask containing a polyimide solution cooled to room temperature, and the mixture was stirred at room temperature for 1 hour to synthesize an amic acid. Then, the temperature was directly raised to 150 °C, and the mixture was stirred for 6 hours while distilling off the by-produced water, thereby obtaining the target bismaleimide compound 1 (number average molecular weight: 32,000) represented by formula (3) of the following Reaction Scheme 1 as a reddish-brown varnish. [Chemical formula]

[0052] [Example 2] (Production of bismaleimide compound 2, Reaction Scheme 2) To a 500 mL three-necked glass flask equipped with a stirrer, a Dean-Stark tube, a condenser, and a thermometer, 27.96 g (52.5 mmol) of 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, 26.02 g (50.0 mmol) of 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride), and 98 g of anisole were added, and the mixture was stirred at 70 °C for 2 hours to synthesize an amic acid. Then, the temperature was directly raised to 150 °C, and the mixture was stirred for 5 hours while distilling off the by-produced water to synthesize a polyimide compound. Subsequently, 0.54 g (5.5 mmol) of maleic anhydride was added to a flask containing a polyimide solution cooled to room temperature, and the mixture was stirred at room temperature for 1 hour to synthesize an amic acid. Then, the temperature was directly raised to 150 °C, and the mixture was stirred for 6 hours while distilling off the by-produced water, thereby obtaining the target bismaleimide compound 2 (number average molecular weight: 21,000) represented by formula (4) of the following Reaction Scheme 2 as a yellow varnish. [Chemical formula]

[0053] [Example 3] (Production of bismaleimide compound 3, Reaction Scheme 3) Into a 500 mL three-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser and a thermometer, 21.55 g (52.5 mmol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 32.13 g (50.0 mmol) of 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride) and 122 g of anisole were added, and the mixture was stirred at 70 °C for 2 hours to synthesize an amic acid. Then, the temperature was directly raised to 150 °C, and the mixture was stirred for 5 hours while distilling off the by-produced water to synthesize a polyimide compound. Thereafter, 0.54 g (5.5 mmol) of maleic anhydride was added to the flask containing the polyimide solution cooled to room temperature, and the mixture was stirred at room temperature for 1 hour to synthesize an amic acid. Then, the temperature was directly raised to 150 °C, and the mixture was stirred for 6 hours while distilling off the by-produced water to obtain the target bismaleimide compound 3 (number average molecular weight: 33,000) represented by formula (5) of Reaction Scheme 3 below as a yellowish-brown varnish. [Chemical formula]

[0054] [Example 4] (Production of bismaleimide compound 4, Reaction Scheme 4) Into a 500 mL three-necked glass flask equipped with a stirrer, a Dean-Stark tube, a cooling condenser and a thermometer, 31.96 g (60.0 mmol) of 9,9-bis[4-(4-aminophenoxy)phenyl]fluorene, 32.13 g (50.0 mmol) of 9,9-bis[4-(3,4-dicarboxyphenoxy)phenyl]fluorene dianhydride and 151 g of anisole were added, and the mixture was stirred at 70 °C for 2 hours to synthesize an amic acid. Then, the temperature was directly raised to 150 °C, and the mixture was stirred for 5 hours while distilling off the by-produced water to synthesize a polyimide compound. Subsequently, 2.16 g (22.0 mmol) of maleic anhydride was added to a flask containing the polyimide solution cooled to room temperature, and the mixture was stirred at room temperature for 1 hour to synthesize an amic acid. Then, the temperature was directly raised to 150°C, and the mixture was stirred for 6 hours while distilling off the by-produced water, thereby obtaining the target bismaleimide compound 4 (number average molecular weight: 11,000) represented by formula (6) of Reaction Scheme 4 below as a brown varnish.

Chemical formula

[0055] [Comparative Example 1] (Production of bismaleimide compound 5, Reaction Scheme 5) To a 500 mL three-necked glass flask equipped with a stirrer, a Dean-Stark tube, a condenser, and a thermometer, 42.93 g (105 mmol) of 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 52.05 g (100 mmol) of 4,4'-(4,4'-isopropylidenediphenoxy)bis(phthalic anhydride), and 171 g of anisole were added, and the mixture was stirred at 70°C for 2 hours to synthesize an amic acid. Then, the temperature was directly raised to 150°C, and the mixture was stirred for 5 hours while distilling off the by-produced water to synthesize a polyimide compound. Subsequently, 1.08 g (11 mmol) of maleic anhydride was added to the flask containing the polyimide solution cooled to room temperature, and the mixture was stirred at room temperature for 1 hour to synthesize an amic acid. Then, the temperature was directly raised to 150°C, and the mixture was stirred for 6 hours while distilling off the by-produced water, thereby obtaining the target bismaleimide compound 5 (number average molecular weight: 20,000) represented by formula (7) of Reaction Scheme 5 below as a pale yellow varnish.

Chemical formula

[0056] The varnishes of bismaleimide compounds 1 to 4 synthesized in Examples 1 to 4 above and the varnish of bismaleimide compound 5 synthesized in Comparative Example 1 above were each adjusted so that the resin amount became 50 g, and 1 g of dicumyl peroxide was dissolved therein to obtain a varnish of the resin composition.

[0057] <Dielectric properties (relative permittivity, dielectric loss tangent)> The varnish of each resin composition prepared above was applied onto an aflex film with a thickness of 100 μm using a roller coater so that the thickness after drying would be 30 μm, and then dried at 80°C for 15 minutes to obtain an uncured resin film. Thereafter, it was post-cured at 180°C for 2 hours to prepare a film-like sample for dielectric property evaluation. Thereafter, before being subjected to measurement, the aflex film was peeled off, a network analyzer (E5063-2D5 manufactured by Keysight Technologies) and a stripline (manufactured by Keycom Co., Ltd.) were connected to the sample, and the relative permittivity and dielectric loss tangent of the film at a frequency of 10 GHz were measured. The measurement results are shown in Table 1.

[0058] <Glass transition temperature (Tg)> Regarding the film-like sample for dielectric property evaluation prepared above, the glass transition temperature was measured using TMA8140C manufactured by Rigaku Corporation. The measurement results are shown in Table 1.

[0059]

Table 1

[0060] It was revealed that the bisimide resin compositions of Examples 1 to 4 had a much higher glass transition temperature of the cured product as compared with the bisimide resin composition of Comparative Example 1.

[0061] [Method for manufacturing prepreg] 259 g of an anisole varnish (nonvolatile content: 39% by mass) of bisimide compound 1 prepared in Example 1, 2 g of dicumyl peroxide, 133 g of a silica dispersion slurry (average particle size: 0.5 μm, solid concentration: 75% by mass, solvent: toluene, trade name: 5SV-CT1, manufactured by Admatechs Co., Ltd.) and 111 g of anisole were mixed to obtain a varnish. A quartz glass cloth (thickness: 90 μm, trade name: SQX2116, manufactured by Shin-Etsu Chemical Co., Ltd.) was impregnated therewith and heated at 120°C for 6 minutes to volatilize the solvent, thereby manufacturing a prepreg (resin composition impregnation amount: 50% by mass).

[0062] [Method for manufacturing copper-clad laminate] Copper foils with a thickness of 18 μm (surface roughness: 0.6 μm) were placed on both sides of the prepreg obtained above, pressed at 1.7 MPa, and heated at 180 °C for 1 hour to manufacture a copper-clad laminate.

[0063] After removing the copper foils on both sides of the copper-clad laminate described above by etching, a network analyzer (E5063-2D5 manufactured by Keysight Technologies) and a stripline (manufactured by Keycom Co., Ltd.) were connected, and the relative permittivity and dielectric tangent of the prepreg at a frequency of 10 GHz were measured. In addition, a glass transition temperature was measured using TMA8140C manufactured by Rigaku Corporation. The results are shown in Table 2.

[0064]

Table 2

[0065] As shown in Table 2, a material with excellent dielectric properties and heat resistance was manufactured.

[0066] [Method for manufacturing printed wiring board] Ten prepregs obtained above and eleven copper foils with a thickness of 18 μm (surface roughness: 0.6 μm) were stacked in order, pressed at 1.7 MPa, and heated at 180 °C for 1 hour to manufacture a copper-clad laminate. A dry resist film with a thickness of 30 μm (NIT430E, manufactured by Nichco Materials Co., Ltd.) was vacuum laminated on this copper-clad laminate at 0.4 MPa at 80 °C for 60 seconds to bond them together. Then, a mask with a circuit pattern formed was brought into contact, irradiated with UV from above, and developed with an aqueous sodium hydrogen carbonate solution. Then, it was impregnated with an etching solution (H-1000A, manufactured by Sanhayat Co., Ltd.) for etching, and washed with an aqueous sodium hydroxide solution to manufacture a printed wiring board with a circuit formed.

Industrial applicability

[0067] The thermosetting bismaleimide resin composition of the present invention can provide a cured product having excellent dielectric properties and heat resistance when formed into a film shape or a substrate shape. Specifically, the thermosetting bismaleimide resin composition of the present invention is useful for applications such as multilayer printed wiring boards used in electronic devices for high-frequency bands that require an insulating material with excellent dielectric properties.

Claims

1. (A) A bismaleimide compound having a fluorene skeleton represented by any of the following formulas (3) to (5): 【Chemical 1】 【Chemical Formula 2】 【Chemical Formula 3】 (In the formula, n is an integer of 2 to 50.) and (B) A reaction accelerator A thermosetting bismaleimide resin composition containing the same.

2. The thermosetting bismaleimide resin composition according to claim 1, wherein the reaction accelerator as component (B) is a radical polymerization initiation catalyst or an anionic polymerization initiation catalyst containing at least one of a nitrogen atom and a phosphorus atom.

3. The thermosetting bismaleimide resin composition according to claim 1, wherein the glass transition temperature of the cured product is 200°C or higher.

4. An uncured resin film comprising the thermosetting bismaleimide resin composition according to any one of claims 1 to 3.

5. A cured resin film comprising a cured product of the thermosetting bismaleimide resin composition according to any one of claims 1 to 3.

6. A prepreg having the thermosetting bismaleimide resin composition according to any one of claims 1 to 3 and a fiber substrate.

7. A substrate containing the thermosetting bismaleimide resin composition according to any one of claims 1 to 3.

8. An adhesive comprising the thermosetting bismaleimide resin composition according to any one of claims 1 to 3.

9. A semiconductor encapsulant comprising the thermosetting bismaleimide resin composition according to any one of claims 1 to 3.

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