Bismaleimide

Abstract

The present invention provides a bismaleimide in which acid components derived from a by-product is sufficiently reduced and which also has improved coatability to glass. The present invention pertains to a bismaleimide in which an amino group of a diamine formed of a reaction product of an aromatic tetracarboxylic acid dianhydride and a dimer diamine is converted into a maleimide, in which the molar ratio of the aromatic tetracarboxylic acid dianhydride to the dimer diamine is in the range of 0.2-0.45, and which has an acid value of 2 mg-KOH / g or less.

Description

[Technical Field] 【0001】 This invention relates to bismaleimide. [Background technology] 【0002】 Electronic components used in electronic devices such as mobile phones, smartphones, and notebook computers are becoming increasingly densely integrated and mounted. The resin materials used in adhesives and encapsulants for these electronic components require materials with low water absorption, high reliability, and excellent heat resistance. A known method involves using bismaleimide, in which the amino group of diadiamine (an aliphatic diamine derived from diamic acid with 24 to 48 carbon atoms, sometimes abbreviated as "DDA") is maleimidized, as a component of compositions used in these adhesives and encapsulants. For example, Patent Document 1 discloses a method using maleimide as a component of an adhesive composition for mounting LED elements. Patent Document 2 discloses a method using bismaleimide as a component of an anisotropic conductive adhesive composition for printed circuit boards. 【0003】 Aliphatic bismaleimides can be obtained by known methods disclosed in Patent Documents 3-5, etc. Specifically, they can be produced, for example, by reacting a diamine with maleic anhydride in a solvent under an acid catalyst to imideize and then purify the mixture. These bismaleimides are also commercially available from Designer Molecules Inc. (sometimes abbreviated as DMI) under trade names such as BMI-689, BMI-1500, BMI-1700, and BMI-3000. These aliphatic bismaleimides contain trace amounts of acidic components such as unclosed maleamic acid, fumamic acid, and Michael adducts (compounds produced by the Michael addition reaction of MAA with an amine, followed by the reaction of maleic anhydride), resulting in an acid value significantly exceeding 2 mg-KOH / g. These acidic components posed a problem when used in electronic components, as they could have adverse effects. For example, when used as adhesives or sealants for semiconductors, they could cause corrosion in semiconductor devices due to the bismaleimide. Furthermore, the acidic components increased the hygroscopicity of bismaleimide, which sometimes led to a deterioration in its electrical properties. 【0004】 As a solution to the aforementioned problem, Patent Documents 6 and 7 describe a manufacturing method in which an aliphatic bismaleimide with a relatively high acid value and residual acid components (crude bismaleimide) is produced, and then impurities such as maleamic acid are removed by reaction with a carbodiimide compound (CDI) to reduce the acid value to 2 mg-KOH / g or less. [Prior art documents] [Patent Documents] 【0005】 [Patent Document 1] Japanese Patent Publication No. 2017-31227 [Patent Document 2] Japanese Patent Publication No. 2015-193725 [Patent Document 3] U.S. statutory invention registration H424 [Patent Document 4] U.S. Public Gazette No. 20080262191 [Patent Document 5] Special Publication No. 10-505599 [Patent Document 6] Japanese Patent Publication No. 2018-115156 [Patent Document 7] Japanese Patent Publication No. 2019-001784 [Overview of the project] [Problems that the invention aims to solve] 【0006】 However, even in bismaleimides with reduced acid-derived impurities such as maleamic acid and an acid value of 2 mg-KOH / g or less, problems still remained. Specifically, the reduced acid value worsened the wettability to glass, impairing the coating properties. 【0007】 Therefore, the present invention aims to solve the above problems by providing a bismaleimide in which the acid component derived from by-products is sufficiently reduced, and in which the coating properties for glass are further improved. [Means for solving the problem] 【0008】 The inventors of the present invention have found that the above problem can be solved by bismaleimide, which is an imide-extended dimagiamine obtained by condensing a dimagiamine and an aromatic tetracarboxylic dianhydride in a specific molar ratio, and have completed the present invention. 【0009】 In other words, the present invention is summarized as follows: A bismaleimide in which the amino group of a diamine, which is a reaction product of an aromatic tetracarboxylic dianhydride and a diamine mainly composed of dimaziamine, is maleimidized, The molar ratio of aromatic tetracarboxylic dianhydride to diadiamine is in the range of 0.2 or more and 0.45 or less. Bismaleimide with an acid value of 2 mg-KOH / g or less. 【0010】 The present invention further, 1Regarding the bis - maleimide, when quantitative comparison is performed using the integral value (A) of the peak corresponding to the proton of the methylene group directly bonded to the nitrogen atom of the maleimide group and the integral value (B) of the peak corresponding to the proton of the methylene group directly bonded to the nitrogen atom of the imide group in 1H - NMR, A / B is 1.2 or more and 7.5 or less. 【0011】 The present invention further relates to the bis - maleimide having a viscosity measured by a B - type viscometer at 25°C of 15 Pa·s or more and 200 Pa·s or less. 【Advantages of the Invention】 【0012】 The bis - maleimide of the present invention has a reduced acid value and good coatability on glass. Therefore, it can be suitably used as a component in the manufacture of electronic components using semiconductors, etc., and in sealing material compositions, adhesive compositions, etc. 【Brief Description of the Drawings】 【0013】 [Figure 1] It is the 1H - NMR chart of the bis - maleimide of Example 1. 【Modes for Carrying Out the Invention】 【0014】 Hereinafter, the present invention will be described in detail. The bismaleimide of the present invention is a product obtained by maleimidizing an oligoimide of a terminal diamine, which is a reaction product (dehydration condensation reaction product) of a diamine mainly composed of dimer diamine (DDA) and an aromatic tetracarboxylic dianhydride. Here, DDA is an aliphatic diamine having 24 to 48 carbon atoms, derived from a dimer acid having 24 to 48 carbon atoms. DDA may contain a double bond derived from the raw material in its structure, or may be hydrogenated thereof. The dimer acid is a fatty acid mainly composed of a dibasic acid of a dicarboxylic acid (for example, a dicarboxylic acid having 24 to 48 carbon atoms (especially 36 carbon atoms)) produced by dimerization of an unsaturated fatty acid (for example, an unsaturated fatty acid having 12 to 24 carbon atoms (especially 18 carbon atoms)) using vegetable oils and fats as a raw material. As DDA, commercially available products such as "Versamine 551" manufactured by Cognis Japan, "Priamine 1074" and "Priamine 1075" manufactured by Croda can be used. 【0015】 In the diamine used in the bismaleimide of the present invention, the main component is dimer diamine, and the content ratio of dimer diamine is preferably 80 mol% or more of the diamine. That is, diamines other than DDA may be used as long as the effects of the present invention are not impaired. Examples of such other diamines include aromatic diamines, heterocyclic diamines, alicyclic diamines, and aliphatic diamines. 【0016】 Aromatic diamines are diamine compounds that have one or more aromatic rings in a single molecule. Specific examples of such aromatic diamines include, for example, p-phenylenediamine (PDA), 4,4'-diaminodiphenyl ether (ODA), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), m-phenylenediamine, 2,4-diaminotoluene, 2,4-diamino-3,5-diethyltoluene, 2,6-diamino-3,5-diethyltoluene, 4,4'-diaminobiphenyl, and 4,4'-diamino-2,2' -Bis(trifluoromethyl)biphenyl (TFMB), 2,2'-dimethyl-4,4'-diaminobiphenyl (DMDB), 9,9-bis(4-aminophenyl)fluorene, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, p-xylylenediamine, m-xylylenediamine, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenyl ether ,3,3'-diaminodiphenyl ether, 1-(4-aminophenyl)-1,3,3-trimethylindan-5-amine, 1-(4-aminophenyl)-1,3,3-trimethylindan-6-amine, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-methylenebis(2, Examples include 6-diethylaniline), bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, and 4,4'-(piperazine-1,4-diyl)dianiline. 【0017】 Heterocyclic diamines are diamine compounds that contain one or more heterocyclic rings and no aromatic rings in a single molecule. A specific example of such a heterocyclic diamine is 1,4-bis(3-aminopropyl)piperazine. 【0018】 Alicyclic diamines are diamine compounds that have one or more alicyclic rings in a single molecule and no aromatic rings. Specific examples of such alicyclic diamines include, for example, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(aminomethyl)norbornane, 3(4),8(9)-bis(aminomethyl)tricyclo[5.2.1.0(2,6)]decane, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, isophoronediamine, 4,4'-methylenebis(cyclohexylamine), and 4,4'-methylenebis(2-methylcyclohexylamine). 【0019】 Aliphatic diamines are diamine compounds that do not contain any alicyclic rings, heterocyclic rings, or aromatic rings in a single molecule. Specific examples of such aliphatic diamines include, for example, 1,4-diaminobutane, 1,10-diaminodecane, 1,12-diaminododecane, 1,7-diaminoheptane, 1,6-diaminohexane, 1,5-diaminopentane, 1,8-diaminooctane, 1,3-diaminopropane, 1,11-diaminoundecane, and 2-methyl-1,5-diaminopentane. 【0020】 The bismaleimide of the present invention may or may not contain diamines other than DDA as a diamine component. If the bismaleimide of the present invention contains other diamines, it is preferable that the other diamines include aromatic diamines from the viewpoint of further reducing the acid component and further improving the coatability on glass, uniformity of thickness, and dielectric properties. The content ratio of other diamines (especially aromatic diamines) to the diamine component is preferably 20 mol% or less (particularly 15% or less). 【0021】 Specific examples of aromatic tetracarboxylic dianhydrides include 4,4'-oxydiphthalic anhydride (ODPA), pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride (BDCP), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride, 4,4'-(4,4'-isopropylidene diphenoxy)diphthalic anhydride (BPADA), 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and 1,3,3a,4,5,9b-hexahydro-5- Examples include (tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione (TDA-100). These may be used individually or in combination of two or more. Among these, ODPA, PMDA, BPDA, and TDA-100 are preferred. 【0022】 The molar ratio of aromatic tetracarboxylic dianhydride to diamine is in the range of 0.2 to 0.45, and is preferably 0.3 to 0.45 from the viewpoint of further reducing the acid component and further improving the coatability on glass, uniformity of thickness, and dielectric properties. If the molar ratio exceeds 0.45, the viscosity of bismaleimide increases, which may result in poor handling during coating. If it is less than 0.2, the improvement of wettability on glass is insufficient, and defects in the coating film, such as repelling or uneven thickness, may occur during coating or curing. 【0023】 The molar ratio of aromatic tetracarboxylic dianhydride to diamine in the bismaleimide of the present invention can be calculated, for example, by performing an NMR measurement under the same conditions as the measurement conditions for the NMR integral ratio (A / B) described later, and based on the results. 【0024】 When the bismaleimide of the present invention is represented by the following general formula (I), for example, the average value of n is 0.25 to 0.82, meaning that it is considered to be a mixture of bismaleimides having structures with different degrees of polymerization, such as the structure when n is 0 and the structure when n is 1 or greater (for example, 1, 2, ...). 【0025】 [ka] 【0026】 In formula (I), R D R is a residue derived from dimaziamine. When the bismaleimide of the present invention contains two or more diamines with different structures, D This is a mixed group of residues derived from two or more of the diamines. R T R is a residue derived from the aforementioned aromatic tetracarboxylic dianhydride. When the bismaleimide of the present invention contains two or more aromatic tetracarboxylic dianhydrides with different structures, T This is a mixed group of residues derived from two or more aromatic tetracarboxylic dianhydrides. 【0027】 The acid value is a parameter that quantitatively represents the amount of acid component remaining in the bismaleimide described above, and the value measured by the neutralization titration method based on JIS K0070 (1992) can be used. From the viewpoint of the impact on the electrical properties when used in electronic components, the acid value of the bismaleimide of the present invention must be 2 mg-KOH / g or less, preferably 1 mg-KOH / g or less, and more preferably 0.5 mg-KOH / g or less. If the acid value is too high, the electrical properties (especially dielectric properties) when the bismaleimide is used in electronic components will deteriorate. 【0028】 The viscosity of the bismaleimide of the present invention is preferably 10 Pa·s or more and 200 Pa·s or less, more preferably 15 Pa·s or more and 200 Pa·s or less, and even more preferably 30 Pa·s or more and 200 Pa·s or less, as measured with a B-type viscometer at 25°C, from the viewpoint of further reducing the acid component and further improving the coatability on glass, thickness uniformity, and dielectric properties. By doing so, good handling properties and coatability on glass can be ensured. 【0029】 In the production of bismaleimide, first, an amic acid obtained by reacting DDA with an aromatic tetracarboxylic dianhydride in a solvent is imidized to obtain a terminal diamine oligoimide. Next, the oligoimide is reacted with maleic anhydride to obtain a terminal maleamic acid oligoimide, and then the maleamic acid portion is imidized to obtain bismaleimide. At this time, it is usually obtained as a crude bismaleimide solution with an acid value of more than 2 mg-KOH / g, with the aforementioned acid-derived by-products remaining. Imidization is preferably carried out at the reflux temperature of the solvent used, while azeotropically removing the water produced by imidization. The reaction temperature during imidization is preferably 150°C or lower, and more preferably 130°C or lower. The reaction time during imidization is preferably 2 hours or more and 12 hours or less, and more preferably 4 hours or more and 10 hours or less. If the reaction time exceeds 12 hours, side reactions such as the formation of vinyl polymers may occur. Furthermore, if the reaction is left for less than two hours, the imidization reaction may not proceed sufficiently, making washing difficult and potentially reducing the yield. 【0030】 The solvent used in the reaction is not limited as long as it dissolves the product, bismaleimide, but amide solvents such as N-methylpyrrolidone (NMP) and dimethylacetamide (DMAc), hydrocarbon solvents such as toluene and xylene, and ether solvents such as glyme and diglyme are preferably used. These solvents can be used individually or in combination of two or more. Among these, a mixed solvent consisting of an amide solvent and a hydrocarbon solvent is preferably used. The mixing ratio is not particularly limited, but in order to maintain the preferred reaction temperature of 150°C or below, a range of (amide solvent) / (hydrocarbon solvent) = 5 / 5 to 1 / 9 (mass ratio) is preferably used. 【0031】 The solid content concentration during the reaction is preferably 20-70% by mass, and more preferably 30-70% by mass. The solid content concentration is the mass percentage of the total mass of the reaction substrates (DDA, aromatic tetracarboxylic dianhydride, and maleic anhydride) relative to the mass of the charging solution (total mass of reaction substrates, solvent, and dehydration catalyst). 【0032】 There are no restrictions on the acid catalyst used in the dehydration and cyclization reaction of maleamic acid, but sulfuric acid, methanesulfonic acid, benzenesulfonic acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, hypophosphoric acid, maleic acid, etc., can be used. These catalysts can be used individually or in combination of two or more. Triethylamine salts of these acids can also be used. When dehydration and cyclization, it is preferable to remove the water produced by maleimidation from the reaction system by azeotropy or the like. The amount of acid catalyst used is not particularly limited, but it can be used in the range of 115 to 650 mol% relative to the moles of DDA. 【0033】 The bismaleimide obtained as described above can be purified by known methods. For example, methods such as liquid-liquid washing, reprecipitation, and recrystallization can be used, and liquid-liquid washing is preferred due to its ease in the manufacturing process. 【0034】 Furthermore, the obtained bismaleimide may be purified using a carbodiimide compound (CDI) to remove acidic impurities, as described in Patent Documents 6 and 7. Specifically, CDI is reacted with the acidic components in the bismaleimide in a solvent, and the urea derivative of CDI, a by-product of the reaction between the acidic components in the bismaleimide and CDI, is removed by washing with water, alcohol (methanol, ethanol, etc.) to obtain a bismaleimide with a low acid value. The amount of CDI used is not particularly limited as long as the carbodiimide group is at least 1 equivalent relative to the acid value of the bismaleimide, and can be appropriately selected in the range of 1 to 1.2 equivalents, for example. The reaction temperature is preferably 30°C to 100°C, and more preferably 40°C to 70°C. 【0035】 CDIs that react with the acidic component in bismaleimide include N,N'-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), bis(2,6-diisopropylphenyl)carbodiimide, diphenylcarbodiimide, di-β-naphthylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, di-t-butylcarbodiimide, N,N'-dicyclohexylcarbodiimide (DCC), poly(1,6-hexamethylenecarbodiimide), poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylenecarbodiimide), poly(1,4-cyclohexylenecarbodiimide), and poly(4,4 Poly(4,4'-diphenylmethanecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(tolylcarbodiimide), poly(methyl-diisopropylphenylenecarbodiimide), poly(1,3,5-triisopropylbenzenecarbodiimide), poly(1,3,5-triisopropylbenzene and 1,5-diisopropylbenzenecarbodiimide), poly(triethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), poly(diisopropylcarbodiimide), etc. can be used, with DIC or EDC being preferred. These CDIs may be used individually or in combination of two or more. 【0036】 There are no restrictions on the solvent used in the reaction between the acid component in bismaleimide and CDI, but alcoholic solvents such as methyl alcohol and ethyl alcohol, and hydrocarbon solvents such as toluene, xylene (o-xylene, m-xylene, p-xylene), ethylbenzene, mesitylene, and solvent naphtha are preferred. 【0037】 The bismaleimide obtained in this way is 1The NMR integral value ratio (A / B) in H-NMR is preferably 1.2 or more and 7.5 or less, more preferably 1.2 or more and 5.0 or less, and even more preferably 1.2 or more and 3.0 or less. Here, A is the integral value of the peak corresponding to the proton of the methylene group directly attached to the nitrogen atom of the maleimide group, and B is the integral value of the peak corresponding to the proton of the methylene group directly attached to the nitrogen atom of the imide group. If the ratio (A / B) is less than 1.2, the viscosity is high and coating properties and thickness uniformity are impaired, and if it is greater than 7.5, wettability to glass is impaired. 【0038】 The bismaleimide of the present invention can be suitably used in the manufacture of electronic components using semiconductors, etc., and as a component of encapsulant compositions, adhesive compositions, and the like. [Examples] 【0039】 The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. 【0040】 (1) Acid value of bismaleimide The measurement was performed by neutralization titration in accordance with the provisions of JIS K0070 (1992). The bismaleimide solution was accurately weighed, diluted with THF to a bismaleimide concentration of approximately 2% by mass, and titrated with potassium hydroxide (KOH) using bromothymol blue (BTB) as an indicator. The value obtained by converting the number of mg of KOH consumed in neutralization to a value per gram of bismaleimide was used. 【0041】 (2) Viscosity of bismaleimide The rotational viscosity at 25±0.2℃ was measured using a Tokimec DVL-BII type digital viscometer (Type B viscometer). 【0042】 (3) Coatability of bismaleimide On the surface of a non-alkali glass substrate with a thickness of 0.7 mm (Corning's "Eagle XG", 20 cm square), bismaleimide was applied by a table coater so that the thickness after curing would be 50 μm, and then heated at 100 °C for 30 minutes, 150 °C for 30 minutes, and 230 °C for 90 minutes to cure. After heat curing, the presence or absence of peeling of the bismaleimide resin layer was visually confirmed. When no peeling was observed, it was marked as "○", and when peeling was observed, it was marked as "×". 【0043】 (4) Thickness uniformity of the bismaleimide film After heat curing, the bismaleimide film was peeled off from the glass substrate, and using a dial gauge ("ID-C112CX" manufactured by Mitutoyo Corporation), the thickness of the film was measured at 1 cm intervals in the MD direction and the TD direction. If the maximum value and the minimum value were within the range of 50 μm ± 5 μm, it was marked as "○", and if outside the range, it was marked as "×". 【0044】 (5) Dielectric properties of the bismaleimide film A film with uniform thickness was used as a sample, and a disk resonator was created on one side. Using a network analyzer (manufactured by Agilent Technologies), the dielectric tangent (Df) was measured at 10 GHz. The measurement was performed 3 times on the same sample, and the average value was taken as the measured value. The dielectric tangent is preferably 0.0022 or less, and a range of 0.0025 or less is practically problem-free (acceptable range). 【0045】 (6) Measurement of the NMR integral value ratio (A / B) Bismaleimide was subjected to 1 1H-NMR measurement under the following measurement conditions. For example, the 1 1H-NMR chart of the bismaleimide of Example 1 is shown in Fig. 1. The integral value of the peak corresponding to the proton of the methylene group directly bonded to the nitrogen atom of the maleimide group was designated as "A". The integral value of the peak corresponding to the proton of the methylene group directly bonded to the nitrogen atom of the imide group was designated as "B". 【0046】 Here, the NMR measurement conditions are as follows. (See Fig. 1) < 1 1H-NMR measurement conditions Equipment: Nuclear Magnetic Resonance Spectrometer (manufactured by JEOL Ltd.: Model ECA500) Frequency: 500.16MHz Reference substance: Tetramethylsilane Solvent: Deuterated chloroform Measurement temperature: 25℃ 【0047】 Under the above measurement conditions, the chemical shift corresponding to the peak of the proton of the methylene group directly connected to the nitrogen atom of the maleimide group of bismaleimide is approximately 3.5 ppm (Peak 1 in Figure 1). Furthermore, the chemical shift corresponding to the peak of the proton of the methylene group directly connected to the nitrogen atom of the imide group of bismaleimide is approximately 3.7 ppm (Peak 2 in Figure 1). Therefore, by reading the integral values ​​of these peaks from the NMR chart, the NMR integral value ratio can be calculated. 【0048】 <Example 1> [Preparation of bismaleimide] In a glass reaction vessel equipped with a reflux condenser with a water separator, a stirrer, and a thermometer, under a nitrogen atmosphere, a mixed solvent consisting of toluene and NMP (mass ratio: toluene / NMP = 80 / 20), 0.20 moles of diamidiamine (Priamine 1075, manufactured by Croda Japan Co., Ltd., molecular weight: 550), 0.09 moles of ODPA, and 0.18 moles of methanesulfonic acid as a catalyst were added and stirred (ODPA / diamidiamine = 0.45 (molar ratio)). The resulting solution was heated under stirring and refluxed. The reaction was refluxed at approximately 125°C for 3 hours while azeotropically separating the water produced by the reaction to obtain oligoimide. The reaction mixture was cooled to room temperature, 0.44 moles of maleic anhydride were added to the reaction vessel, followed by 0.03 moles of methanesulfonic acid as a catalyst. The mixture was refluxed for a further 12 hours, and after removing the water produced by maleimidation from the reaction system, it was cooled to obtain a two-phase orange-yellow solution. The amount of maleic anhydride used was 200 mol% relative to the terminal amino group of the oligoimide, which is a condensate of dimaziamine and an acidic dianhydride (100 mol% is consumed to maleimide the amino group, and the excess 100 mol% of maleic anhydride is converted to maleic acid by the water produced by the reaction and acts as a dehydration and ring-closing catalyst). The amount of maleic anhydride used is the same in the following examples and comparative examples. 【0049】 [Purification of bismaleimide] Subsequently, the upper phase of the obtained solution was removed and washed twice with an aqueous solvent to obtain a bismaleimide solution. The acid value of this bismaleimide was 5.8 mg-KOH / g. Next, 2.2 g of N,N'-diisopropylcarbodiimide (DIC) (an amount equivalent to 1.1 times the acid value of the bismaleimide) and methyl alcohol were added, and the mixture was heated at 60°C for 60 minutes, then cooled to obtain an orange-yellow solution. The obtained solution was purified by washing twice with an aqueous solvent, and the solvent was removed by distillation to obtain bismaleimide (A-1). The viscosity of this bismaleimide was 150 Pa·s, and the acid value was 0.9 mg-KOH / g. Furthermore, this bismaleimide was... 1 The results of measuring H-NMR under the above conditions are shown in Figure 1. As shown in Figure 1, 1A quantitative comparison was performed using the integral values ​​of peak 1 (δ: approximately 3.5 ppm, multiple lines) (A) and peak 2 (δ: approximately 3.7 ppm, multiple lines) (B) observed in the H-NMR chart, and the result was that A / B was 1.2. 【0050】 <Example 2> Bismaleimide (A-2) was obtained in the same manner as in Example 1, except that the amount of ODPA was 0.04 moles and the amount of maleic anhydride was 0.64 moles. The amount of maleic anhydride used in this example is the same as in Example 1, corresponding to 200 mol% of the terminal amino group of the oligoimide, which is a condensate of dimaziamine and acid dianhydride. The same applies to the following examples and comparative examples. 【0051】 <Example 3> Bismaleimide (A-3) was obtained by following the same procedure as in Example 1, except that the amount of ODPA was 0.07 moles and the amount of maleic anhydride was 0.52 moles. 【0052】 <Example 4> Except for replacing ODPA with PMDA, the procedure was carried out in the same manner as in Example 1 to obtain bismaleimide (A-4). 【0053】 <Example 5> Except for replacing ODPA with BPDA, the procedure was carried out in the same manner as in Example 1 to obtain bismaleimide (A-5). 【0054】 <Example 6> Bismaleimide (A-6) was obtained by following the same procedure as in Example 1, except that ODPA was replaced with PMDA, and the amount of PMDA was 0.04 moles and the amount of maleic anhydride was 0.64 moles. 【0055】 <Example 7> Bismaleimide (A-7) was obtained by following the same procedure as in Example 1, except that ODPA was replaced with PMDA, and the amount of PMDA was 0.07 moles and the amount of maleic anhydride was 0.52 moles. 【0056】 <Example 8> Bismaleimide (A-8) was obtained by following the same procedure as in Example 1, except that ODPA was replaced with BPDA, and the amount of BPDA was 0.04 moles and the amount of maleic anhydride was 0.64 moles. 【0057】 <Example 9> Bismaleimide (A-9) was obtained by following the same procedure as in Example 1, except that ODPA was replaced with BPDA, and the amount of BPDA was 0.07 moles and the amount of maleic anhydride was 0.52 moles. 【0058】 <Example 10> The procedure was carried out in the same manner as in Example 1, except that ODPA was replaced with 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)naphtho[1,2-c]furan-1,3-dione (manufactured by Shin-Nippon Rika Co., Ltd., trade name "TDA-100"), to obtain bismaleimide (A-10). 【0059】 <Example 11> Bismaleimide (A-11) was obtained by following the same procedure as in Example 1, except that ODPA was replaced with TDA-100, the amount of TDA-100 was 0.04 moles, and the amount of maleic anhydride was 0.64 moles. 【0060】 <Example 12> Except for using "Priamine 1074" (molecular weight 547) manufactured by Croda Japan Co., Ltd. as the diamidiamine, the procedure was carried out in the same manner as in Example 1 to obtain bismaleimide (A-12). 【0061】 <Example 13> Bismaleimide (A-13) was obtained by following the same procedure as in Example 1, except that the dimaziamine was replaced with priamine 1074, and the amount of ODPA was 0.04 moles and the amount of maleic anhydride was 0.64 moles. 【0062】 <Example 14> Bismaleimide (A-14) was obtained by following the same procedure as in Example 1, except that 0.20 moles of dimaziamine were replaced with 0.18 moles of dimaziamine and 0.02 moles of 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl (TFMB), and the amount of ODPA was 0.07 moles and the amount of maleic anhydride was 0.52 moles. 【0063】 <Example 15> The procedure was carried out in the same manner as in Example 1, except that 0.09 moles of ODPA were replaced with 0.07 moles of ODPA and 0.02 moles of PMDA, to obtain bismaleimide (A-15). 【0064】 <Comparative Example 1> Bismaleimide (B-1) was obtained by following the same procedure as in Example 1, except that the amount of ODPA was 0.11 moles and the amount of maleic anhydride was 0.36 moles. 【0065】 <Comparative Example 2> Bismaleimide (B-2) was obtained by following the same procedure as in Example 1, except that ODPA was not used and the amount of maleic anhydride was set to 0.80 mol. 【0066】 <Comparative Example 3> In Example 1, after maleimidation, bismaleimide (B-3) was obtained by washing twice with an aqueous solvent without reacting with DIC. 【0067】 <Comparative Example 4> In Example 2, after maleimidation, bismaleimide (B-4) was obtained by washing twice with an aqueous solvent without reacting with DIC. 【0068】 Table 1 shows the oligoimide composition of the bismaleimides obtained in the examples and comparative examples, and the molar ratio of aromatic tetracarboxylic dianhydride to DDA. Table 2 shows the evaluation results of viscosity, acid value, coating properties, thickness uniformity, dielectric loss tangent, and quantitative NMR comparisons. 【0069】 [Table 1] 【0070】 [Table 2] 【0071】 As shown in the examples, the bismaleimide of the present invention has a reduced acid value, as well as good coating properties, thickness uniformity, and dielectric properties, achieved by setting the molar ratio of aromatic tetracarboxylic dianhydride to DDA within a specific range. In Comparative Example 1, where the molar ratio was 0.55, it can be seen that the viscosity was high and the coating properties and thickness uniformity were poor. In Comparative Example 2, where aromatic tetracarboxylic dianhydride was not used, it can be seen that the wettability to glass was low and the coating properties and thickness uniformity were poor. In Comparative Examples 3 and 4, the dielectric properties were poor because the acid value was not reduced. [Industrial applicability] 【0072】 The bismaleimide of the present invention has a reduced acid value and good coating properties for glass. Therefore, it can be suitably used in the manufacture of electronic components using semiconductors, etc., and as a component of encapsulant compositions, adhesive compositions, and the like.

Claims

[Claim 1] A bismaleimide in which the amino group of a diamine, which is a reaction product of an aromatic tetracarboxylic dianhydride and a diamine mainly composed of dimaziamine, is maleimidized, The molar ratio of aromatic tetracarboxylic dianhydride to dimaziamine is in the range of 0.2 or more and 0.45 or less. Bismaleimide with an acid value of 2 mg-KOH / g or less. [Claim 2] １ The bismaleimide according to claim 1, wherein, in ¹H-NMR, when a quantitative comparison is made using the integral value (A) of the peak corresponding to the proton of the methylene group directly attached to the nitrogen atom of the maleimide group and the integral value (B) of the peak corresponding to the proton of the methylene group directly attached to the nitrogen atom of the imide group, A / B is 1.2 or more and 7.5 or less. [Claim 3] The bismaleimide according to claim 1 or 2, wherein the viscosity of the bismaleimide, as measured by a B-type viscometer at 25°C, is 15 Pa·s or more and 200 Pa·s or less.

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