Bismaleimide

Abstract

To provide a bismaleimide excellent in mechanical property and handling ability.SOLUTION: A bismaleimide is obtained by subjecting amino groups of an aliphatic diamine to maleimidation where the aliphatic diamine has the following characteristics. 1) The carbon number of a main chain of the aliphatic diamine is 14 to 22. 2) The carbon number of a side chain of the aliphatic diamine is 1 to 6. The bismaleimide can be favorably used for production of electronic components using semiconductors and the like, as a constituent of an encapsulation material composition, an adhesive composition and the like, and also can be used in a field of an ink and a paint where an alcohol-based solvent is generally used.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to bismaleimide.

Background Art

[0002] Electronic components used in electronic devices such as mobile phones, smartphones, and notebook computers are progressing in high-density integration and high-density mounting. For resin materials such as adhesives and encapsulants used in these electronic components, heat-resistant materials with low water absorption and excellent reliability are required. As a component of the composition used in these adhesives, encapsulants, etc., a method of using a maleimide compound in which the amino group of diamin (aliphatic diamine derived from dimer acid having 24 to 48 carbon atoms) is maleimidized is known. For example, it is used as an adhesive composition for mounting LED elements, an anisotropic conductive adhesive composition for printed wiring boards, and a solid composition for semiconductor encapsulation. (Patent Documents 1 to 4)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the above-mentioned conventional bismaleimide is used as a cured product, its mechanical strength may be insufficient.

Means for Solving the Problems

[0005] The inventors of the present invention have found that the above problems can be solved by a bismaleimide composed of a specific aliphatic diamine, and have completed the present invention.

[0006] That is, the gist of the present invention is as follows. A bismaleimide in which the amino groups of an aliphatic diamine are maleimidized, and the bismaleimide in which the aliphatic diamine has the following characteristics. 1) The number of carbon atoms in the main chain of the aliphatic diamine is 14 to 22. 2) The number of carbon atoms in the side chain of the aliphatic diamine is 1 to 6.

Effect of the Invention

[0007] The bismaleimide of the present invention is excellent in mechanical strength when used as a cured product. Further, it is liquid and has a low viscosity, and has good handleability. Furthermore, it has good compatibility with alcohol-based solvents. Therefore, it can be suitably used as a component for manufacturing electronic parts using semiconductors, etc., and for sealing material compositions, adhesive compositions, etc., and can also be used in the fields of inks and paints where alcohol-based solvents are widely used.

Mode for Carrying Out the Invention

[0008] Hereinafter, the present invention will be described in detail. The bismaleimide of the present invention has a chemical structure in which an aliphatic diamine as a raw material and maleic anhydride are dehydrated and condensed.

[0009] The aliphatic diamine is not particularly limited as long as it is a compound having 14 to 22 carbon atoms in the main chain and 1 to 6 carbon atoms in the side chain, but the main chain is preferably a saturated aliphatic. The number of carbon atoms in the main chain is preferably 16 to 20, and the number of carbon atoms in the side chain is preferably 2 to 5. Specific examples of the aliphatic diamine include 6,8-dimethyltetradecane diamine, 7-ethyltetradecane diamine, 7-ethylhexadecane diamine, 7-butylhexadecane diamine, 7-isopropyl-10-methylhexadecane diamine, 7-isobutyl-10-methylhexadecane diamine, 8-ethyloctadecane diamine, 7,12-dimethyloctadecane diamine, 8,13-diethyloctadecane diamine, 8-isopropyl-11-methyloctadecane diamine, 8-methylnonadecane diamine, 9-methylnonadecane diamine, 7,12-dimethyleicosane diamine, and the like. These may be used alone or in combination of two or more. As a commercially available product, "Diamine H20" manufactured by Okamura Oil Co., Ltd. can be preferably used.

[0010] In the method for producing bismaleimide of the present invention, an aliphatic diamine and maleic anhydride are reacted in a solvent to obtain maleamic acid, and then the amic acid portion of maleamic acid is imidized to obtain bismaleimide. Maleic anhydride as a reaction substrate is used in an equimolar amount with respect to the amino group of the aliphatic diamine. The imidization is preferably carried out at the reflux temperature of the used solvent while azeotropically removing the water generated by the imidization. The reaction temperature during the imidization is preferably 150 ° C or lower, more preferably 130 ° C or lower. The reaction time during the imidization is preferably 2 hours or more and 12 hours or less, 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 easily occur. Also, if it is less than 2 hours, the imidization reaction does not proceed sufficiently, washing becomes difficult, and the yield may decrease.

[0011] As the solvent used in the reaction, there is no limitation as long as it can dissolve the product bismaleimide. However, 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 alone or in combination of two or more. Among these, a mixed solvent composed of an amide solvent and a hydrocarbon solvent is preferably used. The mixing ratio is not particularly limited, but in order to be at 150 °C or lower, which is the above-mentioned preferred reaction temperature, a range of (amide solvent) / (hydrocarbon solvent) = 5 / 5 to 1 / 9 (mass ratio) is preferably used.

[0012] The solid content concentration during the reaction is preferably 20 to 70% by mass, and more preferably 30 to 70% by mass. The solid content concentration refers to the mass percentage of the total mass of the reaction substrates (aliphatic diamine and maleic anhydride) with respect to the mass of the charged solution (the total mass of the reaction substrates, solvent, and dehydrating acid catalyst).

[0013] There is no limitation on the acid catalyst used in the dehydration ring-closure reaction of maleamic acid, and sulfuric acid, methanesulfonic acid, benzenesulfonic acid, orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, hypophosphorous acid, maleic acid, etc. can be used. These catalysts can be used alone or in combination of two or more. Also, triethylamine salts of these acids can be used. When performing the dehydration ring-closure, it is preferable to remove the water generated by maleimidation outside the reaction system by azeotropy or the like.

[0014] The bismaleimide solution obtained as described above is purified to obtain a bismaleimide having an acid value of 2 mg-KOH / g or less. That is, in a solvent, a carbodiimide compound (CDI) is reacted 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 is not particularly limited as long as the carbodiimide group is 1 equivalent or more with respect to the acid value according to the acid value of the bismaleimide, and can be appropriately selected, for example, in the range of 1 to 1.2 equivalents. The reaction temperature is preferably 30°C to 100°C, more preferably 40°C to 70°C. The solid content concentration of the bismaleimide is preferably 20 to 70% by mass, more preferably 30 to 70% by mass, based on the solution mass. By 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 preferably 1 mg-KOH / g or less.

[0015] As the CDI to react with the acid component in bismaleimide, 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), poly(4,4′-dicyclohexylmethanecarbodiimide), poly(4,4′-diphenylmethanecarbodiimide), poly(3,3′-dimethyl-4,4′-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(tolylcarbodiimide), poly(methyldiisopropylphenylenecarbodiimide), poly(1,3,5-triisopropylbenzene carbodiimide), poly(1,3,5-triisopropylbenzene and 1,5-diisopropylbenzene carbodiimide), poly(triethylphenylenecarbodiimide), poly(triisopropylphenylenecarbodiimide), 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.

[0016] There is no restriction on the solvent used for the reaction between the acid component in bismaleimide and CDI, but hydrocarbon solvents such as toluene, xylene (o-xylene, m-xylene, p-xylene), ethylbenzene, mesitylene, solvent naphtha, etc. are preferred.

[0017] The bismaleimide thus obtained is preferably liquid at room temperature (25°C) from the viewpoint of handleability, and preferably has a viscosity of 2.0 Pa·s or less as measured with a B-type viscometer at 25°C, more preferably 1.0 Pa·s or less. By doing so, good handleability can be ensured.

[0018] After the bismaleimide of the present invention is applied and dried on a substrate such as a copper foil, it can be made into a bismaleimide cured product by thermally curing the bismaleimide at a temperature of 150°C to 300°C.

[0019] When producing the bismaleimide cured product, it is preferable to blend a catalyst for promoting the curing of the bismaleimide in an amount of 0.05 to 5% by mass based on the mass of the bismaleimide. Examples of such a curing accelerator include dicumyl peroxide, dibenzoyl peroxide, 2-butanone peroxide, tert-butyl perbenzoate, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, tert-butyl hydroperoxide, 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(2-methylbutanenitrile), 1,1'-azobis(cyclohexanecarbonitrile), and the like.

[0020] As the mechanical properties of the bismaleimide cured product of the present invention, it is preferably 1 GPa or more as the flexural modulus described later. Also, the flexural strength is preferably 30 MPa or more.

[0021] The bismaleimide of the present invention can be suitably used as a component for manufacturing electronic components using semiconductors or the like, a sealing material composition, an adhesive composition, etc., and can also be used in the fields of inks and paints where alcohol-based solvents are widely used.

Examples

[0022] Examples are given below to explain the present invention in more detail. Note that the present invention is not limited by the examples.

[0023] (1) Viscosity of Bismaleimide Using a DVL-BII type digital viscometer (B-type viscometer) manufactured by Tokimec, the rotational viscosity was measured in a thermostatic bath with temperature controlled at 25 ± 0.2°C.

[0024] (2) Acid Value of Bismaleimide Measured by the neutralization titration method based on the provisions of JIS K0070 (1992). Bismaleimide was precisely weighed and diluted with THF so that the bismaleimide concentration was approximately 2% by mass. Using bromothymol blue (BTB) as an indicator, titration was performed with potassium hydroxide (KOH), and the value obtained by converting the number of mg of KOH consumed for neutralization per 1 g of bismaleimide was used.

[0025] (3) Solvent Compatibility of Bismaleimide At room temperature, 6 g of bismaleimide was placed in a 20 ml glass sample tube, 4 g of the solvent listed in Table 2 was added, and after stirring for 10 minutes using a magnetic stirrer and then standing for 30 minutes, the state of becoming homogeneous without separation, turbidity, or bubbles was confirmed. ○: Became homogeneous. ×: Did not become homogeneous.

[0026] (4) Mechanical Properties of Bismaleimide Cured Product Dicumyl peroxide was blended with bismaleimide at 1% by mass based on bismaleimide to obtain a uniform bismaleimide for curing. The bismaleimide for curing was poured into a mold made by sandwiching two 3 mm thick U-shaped Teflon (registered trademark) plates between two metal plates, and cured products were manufactured by heating at 100°C for 30 minutes, 150°C for 30 minutes, and 180°C for 90 minutes. Subsequently, based on the provisions of ISO178, the flexural strength and flexural modulus were measured. The higher the flexural strength and flexural modulus, the better the mechanical properties.

[0027] <Example 1> 1) Preparation of Bismaleimide Solution 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), diamine H20 (manufactured by Okamura Oil Co., Ltd., a saturated branched diamine with 20 carbon atoms, molecular weight: 331): 0.17 mol, maleic anhydride: 0.34 mol, p-toluenesulfonic acid as the first acid catalyst: 0.15 mol, and maleic anhydride as the second acid catalyst: 0.22 mol were charged and stirred. The obtained solution was heated with stirring to heat the contents to reflux. While azeotropically separating the water generated by the reaction, reflux was continued at about 125°C for 6 hours, and then it was cooled to obtain a two-phase orange-yellow solution. Thereafter, the upper phase of the obtained solution was taken out and washed twice with an aqueous solvent to obtain a bismaleimide solution having a solid content concentration of 30% by mass with toluene as the solvent. Bismaleimide was obtained by distilling off the solvent. The acid value of this bismaleimide was 8.7 mg-KOH / g.

[0028] 2) Reduction of Acid Value by CDI In a glass reaction vessel equipped with a stirrer and a thermometer, under a nitrogen atmosphere, 200 g of the bismaleimide solution obtained in Example 1, 1.3 g of N,N'-diisopropylcarbodiimide (DIC) (1.05 times equivalent to the acid value of bismaleimide), and methyl alcohol were charged, 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 was obtained by distilling off the solvent. The acid value of this bismaleimide was 0.95 mg-KOH / g.

[0029] <Comparative Example 1> Bismaleimide was obtained in the same manner as in Example 1 except that diamine H20 was changed to dimerdiamine ("Priamine 1074" manufactured by Croda Japan Co., Ltd., molecular weight: 547).

[0030] <Comparative Example 2> Bismaleimide was obtained in the same manner as in Example 1 except that diamine H20 was changed to trimethylhexamethylenediamine. This bismaleimide was solid at 25°C.

[0031] Table 1 shows the types of aliphatic diamines used in the examples and comparative examples, the acid values, viscosities of the obtained bismaleimides, and the mechanical properties of the cured products, and Table 2 shows the evaluation results of the solvent compatibility of the obtained bismaleimides.

[0032]

Table 1

[0033]

Table 2

[0034] As shown in the examples, the bismaleimide of the present invention is excellent in the mechanical properties of the cured product by using a specific aliphatic diamine. Further, it has a low viscosity and has solvent compatibility with alcohol-based solvents. On the other hand, in Comparative Example 1, it can be seen that the mechanical properties of the cured product are inferior and the solvent compatibility with alcohol-based solvents is low. The bismaleimide obtained in Comparative Example 2 was solid at room temperature, so its use was limited in terms of handleability.

Industrial Applicability

[0035] The bismaleimide of the present invention is excellent in mechanical strength when used as a cured product. Further, it is liquid and has a low viscosity, and has good handleability and compatibility with alcohol-based solvents. Therefore, it can be suitably used as a component of a sealing material composition, an adhesive composition, etc. used in the manufacture of electronic parts using semiconductors, etc., and can also be used in the fields of inks and paints where alcohol-based solvents are widely used.

Claims

【Claim 1】 A bismaleimide in which the amino groups of an aliphatic diamine are maleimidized, and the aliphatic diamine has the following characteristics. 1) The number of carbon atoms in the main chain of the aliphatic diamine is 14 to 22. 2) The number of carbon atoms in the side chain of the aliphatic diamine is 1 to 6. **Claim 2** The bismaleimide according to claim 1, wherein the viscosity measured by a B-type viscometer at 25 °C is 2.0 Pa·s or less. **Claim 3** The bismaleimide according to claim 1, wherein the acid value is 2 mg-KOH / g or less. **Claim 4** The bismaleimide according to claim 1, which is compatible with 60 parts by mass or more with respect to 40 parts by mass of 2-propanol. **Claim 5** The bismaleimide according to claim 1, wherein the flexural modulus after curing is 1.0 GPa or more. **Claim 6** A cured product obtained by curing the bismaleimide according to any one of claims 1 to 5.

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