Bismaleimide and method for producing same

Abstract

Provided are: a bismaleimide which is obtained by maleimidizing an amino group of a dimer diamine and which has sufficiently improved mixing compatibility and workability when blended with another agent such as a curable resin; and a method for producing the bismaleimide. The invention relates to bismaleimide, which is formed by carrying out maleimide on an amino group of dimer diamine, and has the following characteristics. (1) The bismaleimide has an acid value of 2 mg-KOH / g or less. 2) The bismaleimide has a viscosity of 3.0 Pa * s or less as measured by a B-type viscometer at 25 DEG C.

Description

Technical Field

[0001] The present invention relates to a bismaleimide and a method for producing the same. Background Art

[0002] Electronic components used in electronic devices such as mobile phones, smartphones, and notebook personal computers are evolving towards high-density integration and high-density mounting. For resin materials such as adhesives and sealing materials used for these electronic components, heat-resistant materials with low water absorption and excellent reliability are required. As a component of a composition used for these adhesives, sealing materials, etc., a method using bismaleimide is known, and the above bismaleimide is obtained by maleimidizing the amino group of a dimer diamine (an aliphatic diamine derived from a dimer acid having 24 to 48 carbon atoms, hereinafter sometimes simply referred to as "DDA"). For example, Patent Document 1 discloses a method of using maleimide as a component of an adhesive composition for mounting an LED element. Patent Document 2 discloses a method of using bismaleimide as a component of an anisotropic conductive adhesive composition for a printed wiring board.

[0003] Aliphatic bismaleimide can be obtained by known methods disclosed in Patent Documents 3 to 5, etc. That is, for example, it can be produced by reacting a diamine with maleic anhydride in a solvent under an acid catalyst for imidization and purification. In addition, these bismaleimides are also commercially available from Designer Molecules Inc. (sometimes simply referred to as DMI) under trade names such as BMI-689, BMI-1500, BMI-1700, and BMI-3000. Since acid components such as maleamic acid, fumaric acid amide, and Michael adduct (a compound formed by Michael addition reaction of MAA and an amine, and further reacting this compound with maleic anhydride) that belong to unclosed rings remain in trace amounts in these aliphatic bismaleimides, the acid value thereof greatly exceeds 2 mg-KOH / g. When these acid components are used for electronic components, there is a problem of having a negative impact on electrical characteristics.

[0004] As a solution to the above problems, Patent Document 6 describes the following production method: after producing a bismaleimide (crude bismaleimide) with a high acid value in which acid components remain, by reacting with a carbodiimide compound (CDI), maleamic acid and the like that belong to impurities are removed, so that the acid value is 2 mg-KOH / g or less.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Laid-Open No. 2017-31227

[0008] Patent Document 2: Japanese Patent Laid-Open No. 2015-193725

[0009] Patent Document 3: U.S. Statutory Invention Registration H424

[0010] Patent Document 4: U.S. Patent Application Publication No. 2008 / 0262191

[0011] Patent Document 5: Japanese Patent Application Laid-Open No. Hei 10-505599

[0012] Patent Document 6: Japanese Patent Laid-Open No. 2018-115156

[0013] Patent Document 7: Japanese Patent Laid-Open No. 2014-132066 SUMMARY OF THE INVENTION

[0014] However, even in a bismaleimide in which impurities derived from an acid such as maleamic acid are reduced and the acid value is 2 mg-KOH / g or less, there are still problems. That is, since the viscosity of the bismaleimide is not sufficiently reduced, it is not easily mixed when combined with other agents such as a curable resin composition, which impairs the workability.

[0015] On the other hand, in the maleimidation reaction, for the purpose of increasing the yield, an alkaline compound such as an aliphatic tertiary amine is sometimes made to coexist (for example, Patent Document 7), but even in such a case, the viscosity of the bismaleimide cannot be sufficiently reduced.

[0016] Therefore, the present invention has been completed to solve the above problems, and an object thereof is to provide a bismaleimide that further sufficiently reduces the viscosity on the basis of sufficiently reducing the acid component derived from by-products.

[0017] The inventors of the present invention conducted intensive studies and found that the above problems can be solved by producing a crude bismaleimide by using two specific acid catalysts in combination and then reacting it with a carbodiimide compound, thereby completing the present invention.

[0018] The present invention has the following gist. A bismaleimide obtained by maleimidating the amino group of a dimer diamine, and having the following characteristics.

[0019] 1) The acid value of the above bismaleimide is 2 mg-KOH / g or less.

[0020] 2) The viscosity of the above bismaleimide measured by a B-type viscometer at 25°C is 3.0 Pa·s or less.

[0021] The present invention further relates to the above bismaleimide, in 1In \(^1\)H-NMR, when quantitatively comparing 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 vinyl proton of the maleimide group, B / A exceeds 0.80.

[0022] The present invention further relates to a method for producing the above-mentioned bismaleimide, which is characterized by including the following steps.

[0023] 1) A step of preparing a crude bismaleimide solution having an acid value exceeding 2 mg-KOH / g using an acid having a pKa of less than 1 and an acid having a pKa of 1 or more as catalysts, and using the above-mentioned catalysts in an amount of 15 mol% or more based on the mole of the diamine dimer.

[0024] 2) A step of reacting the acid component in the above solution with a carbodiimide compound (CDI) to make the acid value 2 mg-KOH / g or less.

[0025] The bismaleimide of the present invention has a low viscosity and its acid value is sufficiently reduced, so it has good miscibility and operability when mixed with other agents such as curable resins. In addition, by making the bismaleimide of the present invention have a low viscosity and a low acid value, although the reason is not clear, its reactivity is significantly improved, and this phenomenon is advantageous in industrial applications when combined with other agents. Therefore, it can be suitably used as components such as a sealing material composition and an adhesive composition used in the manufacture of electronic components using semiconductors and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the 1 \(^1\)H-NMR spectrum of the bismaleimide of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, the present invention will be described in detail. The acid value of the bismaleimide of the present invention is 2 mg-KOH / g or less, and the viscosity measured using a B-type viscometer at 25 °C is 3.0 Pa·s or less.

[0028] Here, the acid value is a parameter that quantitatively represents the amount of acid components remaining in the above-mentioned bismaleimide, and the value measured by the neutralization titration method according to JIS K0070 (1992) can be used. The acid value of the bismaleimide of the present invention is preferably 2 mg-OH / g or less, more preferably 1.7 mg-KOH / g or less, further preferably 1 mg-KOH / g or less, and particularly preferably 0.5 mg-KOH / g or less.

[0029] The viscosity of the bismaleimide of the present invention, as measured by a B-type viscometer at 25°C, needs to be 3.0 Pa·s or less, preferably 2.5 Pa·s or less, and more preferably 2.0 Pa·s or less. In this way, the bismaleimide has a high miscibility when mixed with other agents, ensuring good operability.

[0030] The bismaleimide of the present invention has a chemical structure formed by the dehydration condensation of a dimer diamine (DDA) and a maleic acid component. Here, DDA refers to an aliphatic diamine derived from a dimer acid having 24 to 48 carbon atoms. As DDA, commercially available products such as "Versa mine 551" manufactured by Cognis Japan, "Priamine 1074" and "Priamine 1075" manufactured by Croda can be used.

[0031] In the method for manufacturing the bismaleimide of the present invention, first, in a solvent, in the presence of two acid catalysts, DDA and maleic anhydride are reacted to obtain maleamic acid, and then the amic acid part of the maleamic acid is imidized to form bismaleimide. At this time, a crude bismaleimide solution with an acid value exceeding 2 mg-KOH / g, which is usually a by-product remaining from the acid, can be obtained. The maleic anhydride as the reaction substrate is used in an equivalent amount relative to the amino group of DDA. The imidization is preferably carried out while azeotropically removing the water generated by the imidization at the reflux temperature of the solvent used. As the reaction temperature during the above imidization, it is preferably 150°C or less, more preferably 130°C or less. As the reaction time during the imidization, it is preferably 2 hours to 12 hours, more preferably 4 hours to 10 hours. If the reaction time exceeds 12 hours, side reactions such as the generation of vinyl polymers may easily occur. In addition, if it is less than 2 hours, the imidization reaction is not sufficiently carried out, it is difficult to clean, and sometimes the yield decreases.

[0032] As the acid catalyst, two acid catalysts need to be used in combination. As the first acid catalyst, an acid catalyst with an acid dissociation constant (pKa) less than 1 is used, and as the second acid catalyst, an acid catalyst with a pKa of 1 or more is used. It should be noted that for a polybasic acid, the first acid dissociation constant (pKa1) is used as the pKa of the acid for the selection of the above acid catalyst.

[0033] Specifically, as the first acid catalyst, inorganic acids such as sulfuric acid (pKa: -3) and nitric acid (pKa: -1.4) can be used; organic sulfonic acids such as methanesulfonic acid (pKa: -2.6) and toluenesulfonic acid (pKa: -2.8) can be used. Among them, methanesulfonic acid and toluenesulfonic acid are preferred.

[0034] As the second acid catalyst, an acid catalyst with a pKa of 1 to 7 is preferably used, and various organic carboxylic acids such as aliphatic carboxylic acids can be exemplified. As the second acid catalyst, aliphatic carboxylic acids such as acetic acid (pKa: 4.6), propionic acid (pKa: 4.9), maleic acid (pKa: 1.8), succinic acid (pKa: 4.2), malic acid (pKa: 3.4), fumaric acid (pKa: 3.0) can be exemplified. In addition, aliphatic acid anhydrides can be used as chemical equivalents of aliphatic carboxylic acids for the second acid catalyst. As the aliphatic acid anhydrides, acid anhydrides of acetic acid, propionic acid, maleic acid, succinic acid, malic acid, etc. can be cited. Among the above carboxylic acids or acid anhydrides, maleic acid, malic acid, acetic acid, and their acid anhydrides are preferred.

[0035] The total amount of the two acid catalysts used needs to be 115 mol% or more, preferably 150 mol% or more, relative to the moles of DDA. When the total amount of the acid catalyst used is less than 115 mol%, the effect of viscosity reduction is insufficient. In addition, when the amount of the acid catalyst used is large, the effect saturates. Therefore, considering economy, it is preferably 650 mol% or less, more preferably 520 mol% or less. The amounts of the first acid catalyst and the second acid catalyst used can be appropriately determined within the range of the above total amount. As the amount of the first acid catalyst used, a range of 55 mol% to 285 mol%, more preferably 85 mol% to 230 mol%, relative to the moles of DDA is preferred. Two or more kinds of the first acid catalyst can be used. In this case, their total amount used only needs to be within the range of the amount of the first acid catalyst used above. The amount of the second acid catalyst used is preferably in the range of 55 mol% to 365 mol%, more preferably 65 mol% to 285 mol%, relative to the moles of DDA. Two or more kinds of the second acid catalyst can be used. In this case, their total amount used only needs to be within the range of the amount of the second acid catalyst used above. The use ratio of the first acid catalyst and the second acid catalyst is not particularly limited, but a range of (first acid catalyst) / (second acid catalyst) = 2 / 8 to 8 / 2 (molar ratio) is preferred, a range of 3 / 7 to 7 / 3 is more preferred, and a range of 4 / 6 to 6 / 4 is further preferred. Especially when maleic anhydride is used not only as a raw material for bismaleimide but also as the second acid catalyst, the amount of the second acid catalyst used relative to the moles of the above DDA is the value obtained by subtracting twice the molar amount relative to the moles of DDA from the total amount of maleic anhydride used (that is, the total amount of maleic anhydride used as a raw material for bismaleimide and the amount of maleic anhydride used as the second acid catalyst). This value only needs to be within the range of the amount of the second acid catalyst used relative to the moles of DDA.

[0036] By using two acid catalysts in a specific amount in this way, the maleimidation reaction can be promoted, and by-products such as Michael adducts and vinyl polymers in the manufacturing process of crude bismaleimide can be inhibited, and a crude bismaleimide solution with low viscosity can be obtained.

[0037] When carrying out the maleimidation reaction, for the purpose of increasing the yield, an alkaline compound (such as an aliphatic tertiary amine such as triethylamine) is sometimes made to coexist. However, it is considered that such an alkaline compound forms a salt by a neutralization reaction with the acid catalyst, thereby inactivating a part of the added acid catalyst. Therefore, in the maleimidation reaction of the present invention, it is preferable not to use an alkaline compound. When an alkaline compound coexists, the total amount of the above two acid catalysts used relative to the molar amount of DDA is the value obtained by subtracting the amount of the alkaline compound used relative to the molar amount of DDA from the total amount. This value only needs to be within the range of the total amount of the above two acid catalysts used relative to the molar amount of DDA.

[0038] As the solvent used during the reaction, there is no limitation as long as it is a solvent that dissolves the resulting bismaleimide. It is preferable to use amide solvents such as N-methylpyrrolidone (NMP) and dimethylacetamide (DMAc); hydrocarbon solvents such as toluene and xylene; ether solvents such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether. These solvents can be used alone or in combination of two or more. Among these, it is preferable to use a mixed solvent composed of an amide solvent and a hydrocarbon solvent. The mixing ratio is not particularly limited, and in order to be 150°C or lower, which is the above-mentioned preferable reaction temperature, it is preferable to use a range of (amide solvent) / (hydrocarbon solvent) = 5 / 5 to 1 / 9 (mass ratio).

[0039] As the solid content concentration during the reaction, it is preferably 20 to 70% by mass, more preferably 30 to 70% by mass. It should be noted that the solid content concentration refers to the mass% of the total mass of the reaction substrates (DDA and maleic anhydride) relative to the mass of the input solution (the total mass of the reaction substrates, solvent, and acid catalyst).

[0040] Next, the crude bismaleimide solution obtained in the above manner is purified to obtain a bismaleimide having an acid value of 2 mg-KOH / g or less. That is, in a solvent, CDI reacts with the acid component in the bismaleimide to make the acid value of the bismaleimide 2 mg-KOH / g or less. The amount of CDI used corresponds to the acid value of the crude bismaleimide, and there is no particular limitation as long as the carbodiimide group is 1-fold equivalent or more relative to the acid value, and it can be appropriately selected, for example, in the range of 1 to 1.2-fold equivalents. The reaction temperature is preferably 30°C to 100°C, more preferably 40°C to 70°C. The solid content concentration of the crude bismaleimide is preferably 20 to 70% by mass, more preferably 30 to 70% by mass, relative to the solution mass. Through this reaction, the acid component in the bismaleimide reacts with CDI, and a urea derivative of CDI is by-produced. This urea derivative of CDI can be removed by washing the reaction solution with water, alcohol (such as methanol, ethanol, etc.), that is, by solvent extraction. Then, the solvent is distilled off to obtain a bismaleimide having an acid value of 2 mg-KOH / g or less. The acid value of the purified bismaleimide is more preferably 1 mg-KOH / g or less, and further preferably 0.5 mg-KOH / g or less.

[0041] As the CDI that reacts with the acid component in the crude bismaleimide, N,N'-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), bis(2,6-diisopropylphenyl)carbodiimide, diphenylcarbodiimide, di-β-naphthylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, tert-butylisopropylcarbodiimide, di-tert-butylcarbodiimide, N,N'-dicyclohexylcarbodiimide (DCC), poly(1,6-hexamethylene carbodiimide), poly(4,4'-methylenebiscyclohexylcarbodiimide), poly(1,3-cyclohexylene carbodiimide), poly(1,4-cyclohexylene carbodiimide), poly(4,4'-dicyclohexylmethane carbodiimide), poly(4,4'-diphenylmethane carbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethane carbodiimide), poly(naphthylene carbodiimide), poly(p-phenylene carbodiimide), poly(m-phenylene carbodiimide), poly(tolylene carbodiimide), poly(methyl-diisopropylphenylene carbodiimide), poly(1,3,5-triisopropylbenzene carbodiimide), poly(1,3,5-triisopropylbenzene and 1,5-diisopropylbenzene carbodiimide), poly(triethylphenylene carbodiimide), poly(triisopropylphenylene carbodiimide), poly(diisopropylcarbodiimide), etc. can be used, and DIC or EDC is preferred. These CDIs can be used alone or in combination of two or more.

[0042] There is no limitation on the solvent used in the reaction of the acid component in the crude bismaleimide with CDI, but hydrocarbon solvents such as toluene, xylene (o-xylene, m-xylene, p-xylene), ethylbenzene, mesitylene, and solvent naphtha are preferred.

[0043] The bismaleimide obtained in this way preferably has its 1 The NMR integral value ratio (B / A) of 1H-NMR exceeds 0.80, more preferably 0.82 or more. Further, B / A is further preferably 0.85 or more, and even more preferably 0.87 or more. Here, A is the integral value of the peak corresponding to the proton of the methylene group directly bonded to the nitrogen atom of the maleimide group, and B is the integral value of the peak corresponding to the vinyl proton of the maleimide group. The higher this integral value ratio, the higher the content of the maleimide group in the bismaleimide, that is, when DDA reacts with maleic acid, the formation of Michael adducts and vinyl polymers belonging to by-products can be inhibited, and as a result, it means that the substances that cause an increase in viscosity can be reduced.

[0044] Here, the NMR measurement conditions are as follows. (Refer to Figure 1 )

[0045] < 1 1H-NMR Measurement Conditions>

[0046] Apparatus: Nuclear magnetic resonance apparatus (manufactured by JEOL Ltd.: model ECA500)

[0047] Frequency: 500.16 MHz

[0048] Reference substance: Tetramethylsilane

[0049] Solvent: Deuterochloroform

[0050] Measurement temperature: 25 °C

[0051] Under the above measurement conditions, the chemical shift of the peak corresponding to the proton of the methylene group directly bonded to the nitrogen atom of the maleimide group in the bismaleimide is about 3.5 ppm ( Figure 1 Peak 1). In addition, the chemical shift of the peak corresponding to the vinyl proton of the maleimide group in the bismaleimide is about 6.7 ppm ( Figure 1 Peak 2). Therefore, by reading the integral values of these peaks from the NMR spectrum, the NMR integral value ratio can be calculated.

[0052] As the molecular weight of the bismaleimide of the present invention, the weight-average molecular weight measured by GPC described later is preferably in the range of 1400 to 1800, more preferably in the range of 1450 to 1700, further preferably in the range of 1450 to 1620, and further preferably in the range of 1450 to 1520.

[0053] The bismaleimide of the present invention has excellent curing reactivity, so it exhibits a short gel time. Specifically, the gel time refers to the gel time at 180°C of a homogeneous composition obtained by adding 0.6 g of dicumyl peroxide as a curing agent to 30 g of bismaleimide and stirring, and the value measured in accordance with JIS K6910 is used. The gel time of the bismaleimide of the present invention is generally 300 seconds or less, preferably 280 seconds or less, more preferably 220 seconds or less, and still more preferably 180 seconds or less. The lower limit value of the gel time of the bismaleimide of the present invention is not particularly limited, and this gel time can generally be 50 seconds or more (especially 100 seconds or more).

[0054] The bismaleimide of the present invention can be used as a resin composition by being blended with epoxy resins, phenolic resins, compounds containing unsaturated bonds, benz azine compounds, polyimide resins, polyamideimide resins, etc. The blending amount can be determined according to the use purpose and is not particularly limited. For example, it is in the range of 5 to 50 parts by mass in 100 parts by mass of the resin composition.

[0055] Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol E type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, polyoxynaphthylene type epoxy resin, bisphenol A novolak type epoxy resin, biphenyl type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, xylenol novolak type epoxy resin, polyfunctional phenol type epoxy resin, naphthalene type epoxy resin, naphthalene skeleton-modified novolak type epoxy resin, naphthyl ether type epoxy resin, phenol aralkyl type epoxy resin, anthracene type epoxy resin, 3-functional phenol type epoxy resin, 4-functional phenol type epoxy resin, triglycidyl isocyanurate, glycidyl ester type epoxy resin, alicyclic epoxy resin, dicyclopentadiene novolak type epoxy resin, biphenol novolak type epoxy resin, phenol aralkyl novolak type epoxy resin, naphthol aralkyl novolak type epoxy resin, aralkyl novolak type epoxy resin, biphenyl aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, polyol type epoxy resin, phosphorus-containing epoxy resin, glycidylamine, compounds obtained by epoxidizing double bonds such as butadiene, etc.

[0056] As phenolic resins, examples include bisphenol A type phenolic resin, bisphenol E type phenolic resin, bisphenol F type phenolic resin, bisphenol S type phenolic resin, phenol novolac resin, bisphenol A novolac type phenolic resin, glycidyl ester type phenolic resin, aralkyl phenol novolac type phenolic resin, biphenyl aralkyl type phenolic resin, cresol novolac type phenolic resin, polyfunctional phenolic resin, naphthol resin, naphthol novolac resin, polyfunctional naphthol resin, anthracene type phenolic resin, naphthalene skeleton modified phenol novolac type phenolic resin, phenol aralkyl type phenolic resin, naphthol aralkyl type phenolic resin, dicyclopentadiene type phenolic resin, biphenyl type phenolic resin, alicyclic phenolic resin, polyol type phenolic resin, phosphorus-containing phenolic resin, hydroxyl group-containing organosilicon resin, etc.

[0057] As compounds containing unsaturated bonds, examples include vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, divinylbiphenyl; (meth)acrylic acid esters of monohydric or polyhydric alcohols such as methyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate; epoxy (meth)acrylic acid esters such as bisphenol A type epoxy (meth)acrylate, bisphenol F type epoxy (meth)acrylate, etc.

[0058] As benz azine compounds, examples include 6,6-(1-methylethylidene)bis(3,4-dihydro-3-phenyl-2H-1,3-benz azine), 6,6-(1-methylethylidene)bis(3,4-dihydro-3-methyl-2H-1,3-benz azine), etc. In addition, as commercially available products, examples include "Benz azine F-a type", "Benz azine P-d type" manufactured by Shikoku Kasei Kogyo Co., Ltd., "RLV-100" manufactured by AIR·WATER Inc., etc.

[0059] The resin composition containing the bismaleimide of the present invention can be applied to a wide range of uses such as the core substrate or cover film of FPC, copper-clad laminate, passivation film, protective film, and interlayer insulating film on the surface of semiconductor elements of semiconductor devices, as well as conformal coating of printed circuit boards, surface protective film of solar cells, alignment film of liquid crystal surface elements, protective film of glass fibers, printing paste compositions, conductive paste compositions, etc.

[0060] Examples

[0061] Hereinafter, examples are given to explain the present invention in further detail. It should be noted that the present invention is not limited to the examples.

[0062] <Acid value>

[0063] According to the provisions of JIS K0070 (1992), it is measured by the neutralization titration method. Approximately 1.0 g of bismaleimide is precisely weighed, and the bismaleimide concentration is roughly diluted to 2% by mass with THF. Using bromothymol blue (BTB) as an indicator, it is titrated with potassium hydroxide (KOH), and the mg number of KOH consumed for neutralization is converted into the value per 1 g of bismaleimide.

[0064] <Viscosity>

[0065] Using a DVL - BII type digital viscometer (B - type viscometer) manufactured by TOKIMEC, the rotational viscosity is measured in a constant temperature bath with the temperature controlled at 25 ± 0.2°C.

[0066] <Weight - average molecular weight (Mw)>

[0067] It is measured by GPC. The measurement conditions are as follows.

[0068] Chromatographic column: 1 piece of Shodex(R) GPC KF - 803 manufactured by Showa Denko KK, 2 pieces of GPC KF - 804 (3 pieces in series)

[0069] Eluent: THF

[0070] Temperature: 40°C

[0071] Flow rate: 1.0 mL / minute

[0072] Detector: UV detector

[0073] <Mixing compatibility>

[0074] At room temperature, 5 g of 2,2 - bis(4 - glycidyloxyphenyl) propane, which belongs to a general epoxy resin prepolymer, is placed in a 20 - ml glass sample tube, and 5 g of bismaleimide is added. It is shaken by hand or stirred using a magnetic stirrer as needed, and the case where it becomes a state without separation, turbidity, or bubbles (uniform state) is confirmed.

[0075] ○: Immediately shows a uniform state by shaking by hand.

[0076] △: Becomes a uniform state within 5 minutes by stirring with a stirrer.

[0077] ×: Does not show a uniform state even after stirring with a stirrer for 10 minutes.

[0078] <Gel time>

[0079] As an index of the curing reactivity, the gel time was measured according to the following procedure.

[0080] 0.6 g of dicumyl peroxide as a curing agent was added to 30 g of bismaleimide and stirred to obtain a uniform composition. The gel time of the obtained composition at 180°C was measured in accordance with JIS K6910.

[0081] Specifically, 0.5 g of the composition was dropped onto a hot plate at 180°C, and the stopwatch was started. The composition was stirred with a spatula, and when the viscosity increased and no filaments were drawn out when the spatula was pulled up, that moment was taken as the end point, and the measurement time was recorded as the gel time.

[0082] A composition having a gel time of 300 seconds or less was regarded as acceptable.

[0083] <Example 1>

[0084] 1) Preparation of crude bismaleimide solution

[0085] Under a nitrogen atmosphere, a mixed solvent composed of toluene and NMP (mass ratio: toluene / NMP = 80 / 20), 0.17 mol of dimer diamine (“PRIAMINE 1074” manufactured by Croda Japan Co., Ltd., molecular weight: 547), 0.34 mol of maleic anhydride, 0.15 mol of p-toluenesulfonic acid as a first acid catalyst, and 0.22 mol of maleic anhydride as a second acid catalyst were put into a glass reaction vessel equipped with a reflux condenser with a water separator, a stirrer, and a thermometer, and stirred. The obtained solution was heated under reflux while stirring to heat the contents. While azeotropically separating the water generated by the reaction, after continuously refluxing at about 125°C for 6 hours, it was cooled to obtain a two-phase orange-yellow solution. Then, the upper phase of the obtained solution was taken out and washed twice with an aqueous solvent to obtain a crude bismaleimide solution having a solid content concentration of 30% by mass with toluene as a solvent. The acid value of this crude bismaleimide was 8.2 mg-KOH / g.

[0086] 2) Reduction of acid value using CDI

[0087] Under a nitrogen atmosphere, into a glass reaction vessel equipped with a stirrer and a thermometer, the above-mentioned crude bismaleimide solution (200 g), N,N'-diisopropylcarbodiimide (DIC, 1.2 g, 1.05-fold equivalent relative to the acid value of the crude bismaleimide), and methanol were added. After heating at 60 °C for 60 minutes, it was cooled to obtain an orange-yellow solution. The obtained solution was purified by washing twice with an aqueous solvent, and bismaleimide (A-1) was obtained by distilling off the solvent. The acid value of this bismaleimide was 0.97 mg-KOH / g, and the viscosity was 2.5 Pa·s. The 1 1H-NMR of this bismaleimide was measured under the above conditions, and the results are shown in Figure 1 . As Figure 1 shown, the integral value (A) of peak 1 (δ: about 3.5 ppm, multiplet) and the integral value (B) of peak 2 (δ: about 6.7 ppm, singlet) that appeared in this 1 1H-NMR spectrum were quantitatively compared, and the result of B / A was 0.86.

[0088] <Example 2>

[0089] Maleic acid (0.12 mol) was used as the second acid catalyst, and the amount of DIC was 1.9 g (1.05-fold equivalent relative to the acid value of the crude bismaleimide). Otherwise, the procedure was the same as in Example 1 to obtain bismaleimide (A-2).

[0090] <Example 3>

[0091] Methanesulfonic acid (0.31 mol) was used as the first acid catalyst, maleic anhydride (0.32 mol) was used as the second acid catalyst, and the amount of DIC was 0.6 g (1.1-fold equivalent relative to the acid value of the crude bismaleimide). Otherwise, the procedure was the same as in Example 1 to obtain bismaleimide (A-3).

[0092] <Example 4>

[0093] Methanesulfonic acid (0.31 mol) was used as the first acid catalyst, maleic acid (0.26 mol) was used as the second acid catalyst, and the amount of DIC was 1.1 g (1.0-fold equivalent relative to the acid value of the crude bismaleimide). Otherwise, the procedure was the same as in Example 1 to obtain bismaleimide (A-4).

[0094] <Example 5>

[0095] The first acid catalyst was set as methanesulfonic acid: 0.39 mol, the second acid catalyst was set as maleic anhydride: 0.49 mol, and the amount of DIC was set as 1.2 g (1.03 times equivalent to the acid value of the crude bismaleimide). Other than this, it was carried out in the same manner as in Example 1 to obtain bismaleimide (A-5).

[0096] <Comparative Example 1>

[0097] The first acid catalyst was set as methanesulfonic acid: 0.31 mol, the second acid catalyst was not used, and the amount of DIC was set as 2.3 g (1.1 times equivalent to the acid value of the crude bismaleimide). Other than this, it was carried out in the same manner as in Example 1 to obtain bismaleimide (B-1).

[0098] <Comparative Example 2>

[0099] The first acid catalyst was not used, the second acid catalyst was set as maleic anhydride: 0.32 mol, and the amount of DIC was set as 3.0 g (1.1 times equivalent to the acid value of the crude bismaleimide). Other than this, it was carried out in the same manner as in Example 1 to obtain bismaleimide (B-2).

[0100] <Comparative Example 3>

[0101] The first acid catalyst was set as methanesulfonic acid: 0.09 mol, the second acid catalyst was set as maleic anhydride: 0.10 mol, and the amount of DIC was set as 2.2 g (1.1 times equivalent to the acid value of the crude bismaleimide). Other than the above, it was carried out in the same manner as in Example 1 to obtain bismaleimide (B-3).

[0102] <Comparative Example 4>

[0103] According to the description in Patent Document 6, Example 12, a crude bismaleimide was obtained. In contrast, similar to Example 1, a CDI reaction was carried out to obtain a purified bismaleimide (B-4). That is, a solution formed by dissolving 0.058 mol of Versamine 552 in 90 ml of tetrahydrofuran (THF) was slowly added to a solution formed by dissolving 0.127 mol of maleic anhydride in 60 ml of THF. After 1 hour of addition, 125 mL of acetic anhydride was added, and the reaction mixture was stirred for 24 hours. The reaction mixture was refluxed and maintained at this reflux temperature for 3 hours. After adding 0.1 g of benzoquinone to the reaction mixture, the solvent was removed under vacuum. 75 mL of THF and 1-hydroxybenzotriazole (HOBt) were added to the obtained residue, dissolved at room temperature, and stirred for 24 hours. Then, the solvent was removed at 30 °C, and the residue was extracted twice with 500 mL of pentane. These pentane portions were combined. If it was cooled in a dry ice / isopropanol bath, a white solid precipitated. Therefore, by cold filtering and then concentrating it, a crude bismaleimide solution with a bismaleimide concentration of 50% by mass using pentane as the solvent was obtained. The acid value of this crude bismaleimide was 9.8 mg-KOH / g. 1.5 g of DIC (1.1 times the equivalent amount relative to the acid value of the crude bismaleimide) was added to 120 g of the obtained crude bismaleimide solution, methanol was added, and after heating at 60 °C for 60 minutes and then cooling, an orange-yellow solution was obtained. The obtained solution was purified by washing twice with an aqueous solvent, and bismaleimide (B-4) was obtained by distilling off the solvent.

[0104] <Comparative Example 5>

[0105] According to the description in Patent Document 6, Example 13, a crude bismaleimide was obtained. In contrast, similar to Example 1, a CDI reaction was carried out to obtain a purified bismaleimide (B-5). That is, a solution formed by dissolving 0.096 mol of Versamine 552 in 60 mL of THF was slowly added to a solution formed by dissolving 0.206 mol of maleic anhydride in 300 mL of THF. After the addition was completed, the reaction mixture was stirred for one hour. Then, HOBt was dissolved therein. The stirred reaction mixture was cooled in an ice bath, and then 0.238 mol of DCC was added little by little. After this addition was completed, the reaction mixture was further stirred in the ice bath for 1 hour. Then, the ice bath was removed, and the stirred reaction mixture was allowed to warm to room temperature overnight. The reaction mixture was filtered, and the obtained solid was washed with THF. All these THF portions were combined, 0.2 g of methoxyphenol was added thereto, and then THF was removed at 30°C. After extracting the residue with hexane, the hexane was removed. Then, by extracting it again with pentane, a crude bismaleimide solution with a bismaleimide concentration of 50% by mass in pentane as the solvent was obtained. The acid value of this crude bismaleimide was 6.7 mg-KOH / g. 1.0 g of DIC (1.1 times the equivalent amount relative to the acid value of the crude bismaleimide) was added to 120 g of the obtained crude bismaleimide solution, methanol was added, and after heating at 60°C for 60 minutes and then cooling, an orange-yellow solution was obtained. The obtained solution was purified by washing twice with an aqueous solvent, and bismaleimide (B-5) was obtained by distilling off the solvent.

[0106] <Comparative Example 6>

[0107] According to the descriptions in Patent Document 7 and Synthesis Example 1, crude bismaleimide was obtained. In contrast, CDI reaction was carried out in the same manner as in Example 1 to obtain purified bismaleimide (B-6). That is, triethylamine (38.45 g, 0.380 mol) was added to toluene (200 mL), and methanesulfonic acid (37.44 g, 0.390 mol) was added dropwise with stirring. After stirring at room temperature for 30 minutes, maleic anhydride (25.90 g, 0.264 mol) was added, and then Priamine 1074 (56.98 g, 0.104 mol) was added dropwise. After stirring at room temperature for 30 minutes, the mixture was refluxed at 110 °C for 8 hours to remove water in the system. The resulting reaction solution was washed with brine, filtered through silica gel, and toluene was distilled off under reduced pressure to obtain crude bismaleimide. The acid value of this crude bismaleimide was 26.0 mg-KOH / g. The obtained crude bismaleimide was dissolved in toluene, 3.9 g of DIC (1.1-fold equivalent relative to the acid value of the crude bismaleimide) was added to 200 g of a solution with a bismaleimide concentration of 30% by mass, methanol was added, and the mixture was heated at 60 °C for 60 minutes and then cooled to obtain an orange-yellow solution. The obtained solution was purified by washing twice with an aqueous solvent, and bismaleimide (B-6) was obtained by distilling off the solvent.

[0108] The amounts of acid catalysts used in the examples and comparative examples, the acid values of the crude bismaleimides, and the amounts of CDI used are shown in Table 1, and the acid values, viscosities, NMR quantity comparisons, molecular weights, cured product formulations, and evaluation results of the curing reactivity of the obtained bismaleimides are shown in Table 2.

[0109]

[0110]

[0111] As shown in the examples, the bismaleimide of the present invention uses two specific catalysts in combination, so that in addition to reducing the acid value, the viscosity can be sufficiently reduced. In addition, the mixing compatibility is high when other agents are compounded, and it can be seen that the operability is greatly improved. Furthermore, compared with the comparative examples, the gel time is greatly shortened, and it can be seen that the reactivity is greatly improved. In Comparative Example 1 using only an acid catalyst with a pKa of less than 1 and Comparative Example 2 using only an acid catalyst with a pKa of 1 or more, the viscosities are both high, indicating poor mixing compatibility. As shown in Comparative Example 3, even when an acid catalyst with a pKa of less than 1 and an acid catalyst with a pKa of 1 or more are used in combination, if the amount of the catalyst is small, the viscosity will be high. Furthermore, even in Comparative Examples 4 and 5 according to Patent Document 6, although the acid value is reduced, the viscosity is high, indicating poor mixing compatibility. In addition, the reactivity during curing is insufficient. As shown in Comparative Example 6, when an acid catalyst and triethylamine belonging to a basic compound are used in combination during the synthesis of crude bismaleimide, since the acid catalyst is neutralized, the combined effect of the catalysts cannot be obtained, and the reduction of the viscosity is insufficient. In addition, the reactivity during curing is insufficient.

[0112] Industrial availability

[0113] The bismaleimide of the present invention has a low viscosity and the acid value is sufficiently reduced. Therefore, when compounded with other agents such as a curable resin, the mixing compatibility and operability are good. In addition, the reactivity during curing is greatly improved. Therefore, it can be suitably used as a component of a sealing material composition, an adhesive composition, etc. used in the manufacture of electronic components using semiconductors and the like.

Claims

1. A bismaleimide is formed by maleimidation of the amino groups of a dimer diamine, and is characterized in that: 1) The acid value of the bismaleimide is 2 mg-KOH / g or less, 2) The viscosity of the bismaleimide measured using a B-type viscometer at 25 °C is 3.0 Pa·s or less.

2. The bismaleimide according to claim 1, characterized in that, In 1 H-NMR, when quantitatively comparing 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 vinyl proton of the maleimide group, B / A exceeds 0.

80.

3. A method for manufacturing a bismaleimide, which is the method for manufacturing the bismaleimide according to claim 1 or 2, characterized in that, It includes the following steps: 1) A step of preparing a crude bismaleimide solution with an acid value exceeding 2 mg-KOH / g by using an acid with a pKa less than 1 and an acid with a pKa of 1 or more as catalysts, and using the catalyst in an amount of 115 mol% or more based on the mole of the dimer diamine; 2) A step of making the acid value 2 mg-KOH / g or less by reacting the acid component in the solution with a carbodiimide compound (CDI).

4. A resin composition comprising: the bismaleimide according to claim 1 or 2; and at least one selected from the group consisting of epoxy resins, phenolic resins, compounds containing unsaturated bonds, benz azine compounds, polyimide resins, and polyamideimide resins.

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