Dihydroxy compound, epoxy resin, production method thereof, epoxy resin composition, and cured product

Abstract

To provide an epoxy resin and a dihydroxy compound which are capable of forming a cured product that has good moldability and is also excellent in heat resistance, low thermal expansion, moisture resistance, etc., and are useful for applications such as lamination, molding, casting and adhesion.SOLUTION: The epoxy resin is represented by general formula (2) in the figure, where X represents a single bond, -CH2-, -O-, -CO-, -SO2-, or -C(CF3)2-; A represents an optionally substituted naphthylene group; and n represents a number from 0 to 50.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a dihydroxy compound and an epoxy resin that provide a cured product having excellent moldability as well as excellent heat resistance, low thermal expansion, moisture resistance, etc., and to an epoxy resin composition using the same and a cured product thereof, which are suitable for use in fields such as printed wiring boards, insulating materials in the electrical and electronic fields such as semiconductor encapsulation, carbon fiber composite materials, etc. [Background technology]

[0002] In recent years, with the progress of advanced materials in particular, there has been a demand for the development of base resins with higher performance, and in addition to improved functionality such as heat resistance and moisture resistance, there is also a demand for resins with excellent flame retardancy from the viewpoints of environmental friendliness and safety. In addition, improving the handling properties, such as solvent solubility, when preparing epoxy resin compositions is also an important issue.

[0003] However, none of the epoxy resins known to date fully satisfy these requirements. For example, Patent Document 1 proposes an epoxy resin derived from a phenol aralkyl resin, but its heat resistance and moisture resistance are insufficient. Patent Document 2 proposes an epoxy resin containing an ether ether ketone group, a unit of super engineering plastics, but it suffers from poor moldability and still lacks heat resistance. Patent Document 3 proposes an epoxy resin composition using a bisphenol compound having an imide ring as a curing agent, but due to the inclusion of an isopropylidene structure, its heat resistance is insufficient. Patent Document 4 discloses a bisphenol-based epoxy compound having an imide group, but due to the inclusion of an isopropylidene structure, its heat resistance is also insufficient. Patent Document 5 proposes a specific bisimide phenol derivative, but when made into an epoxy resin, its solvent solubility and compatibility with the curing agent remain poor, making it difficult to prepare an epoxy resin composition and resulting in insufficient heat resistance, such as thermal decomposition stability. Patent Document 6 proposes an epoxy resin containing an imide skeleton, but because the structure is one in which bisphenols are copolymerized to ensure solvent solubility, the heat resistance, such as thermal decomposition stability, is still insufficient. Non-Patent Document 1 proposes an epoxy resin obtained from N,N'-bis(5-hydroxy-1-naphthyl)pyromellitdiimide, but due to the high rigidity of the pyromellitimide group, there are still issues with solvent solubility and compatibility with curing agents. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 63-238122 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-46615 [Patent Document 3] Japanese Patent Application Publication No. 4-328121 [Patent Document 4] Japanese Patent Application Publication No. 4-36753 [Patent Document 5] Japanese Patent Application Laid-Open No. 2011-173827 [Patent Document 6] Japanese Patent Application Laid-Open No. 2010-90360 [Non-patent literature]

[0005] [Non-Patent Document 1] H. Ren, J. Sun, Q. Zhao, Q. Zhou, Qi. Ling, Polymer 49 (2008) 5249-5253 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a dihydroxy compound and an epoxy resin which have good solvent solubility and moldability, and which can give a cured product exhibiting excellent heat resistance and moisture resistance, and which are useful in applications such as lamination, molding, casting, and adhesion, as well as a method for producing the same, an epoxy resin composition using the same, and a cured product thereof. [Means for solving the problem]

[0007] That is, the present invention relates to a novel dihydroxy compound represented by the following general formula (1). [ka] (wherein X represents a single bond, —CH—, —O—, —CO—, —SO—, or —C(CF)—, and A represents a naphthylene group which may have a substituent.)

[0008] The present invention also relates to a novel epoxy resin represented by the following general formula (2): [ka] (Here, A and X have the same meanings as in formula (1), and n represents a number from 0 to 50.)

[0009] The present invention also provides a method for producing an epoxy resin of the above general formula (2), which comprises reacting a dihydroxy compound of the above general formula (1) with epichlorohydrin.

[0010] Furthermore, the present invention relates to an epoxy resin composition containing the dihydroxy compound of the general formula (1) or the epoxy resin of the general formula (2) as an essential component of an epoxy resin in an epoxy resin component or a curing agent in a curing agent component, and also to a cured product obtained by curing such an epoxy resin composition. [Effects of the Invention]

[0011] The cured product obtained by curing the epoxy resin composition of the present invention containing as an essential component an epoxy resin having a naphthalene and an imide structure or a dihydroxy compound has good solvent solubility and moldability, as well as excellent properties such as heat resistance, low thermal expansion, and moisture resistance, and is suitable for use in applications such as lamination, molding, casting, and adhesion. [Brief explanation of the drawings]

[0012] [Figure 1] 1 shows an IR chart of epoxy resin A obtained in Example 1. [Figure 2] 1 shows an IR spectrum of epoxy resin A obtained in Example 3. [Figure 3] 1 shows the H-NMR spectrum of epoxy resin A obtained in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below. The dihydroxy compound of the present invention is represented by general formula (1). [ka]

[0014] Here, X represents a single bond, -CH2-, -O-, -CO-, -SO2-, or -C(CF3)2-. From the viewpoint of heat resistance, a single bond, -O-, or -CO- is preferred, and from the viewpoints of solvent solubility and moldability, -O-, -SO2-, or -C(CF3)2- is preferred. Furthermore, A represents a naphthylene group which may have a substituent. Examples of naphthylene groups include 1,4-substituted, 1,5-substituted, 1,6-substituted, 2,6-substituted, and 2,7-substituted groups, with the 1,5-substituted group being preferred from the viewpoints of solvent solubility and heat resistance. In other words, it is preferred that the 1- and 5-positions of naphthalene are bonded to a hydroxy group or an imide group. Furthermore, the substituent may be, for example, an alkyl group.

[0015] The dihydroxy compound of the present invention has a hydroxyl group equivalent weight in the range of preferably 250 to 3,000 g / eq., more preferably 280 to 1,000 g / eq., and even more preferably 290 to 500. The melting point or softening point is preferably in the range of 120 to 350°C, and more preferably 150 to 300°C.

[0016] The epoxy resin of the present invention is represented by general formula (2). [ka] Here, X and A have the same meanings as in formula (1).

[0017] In general formula (2), n is the repeating number and represents a number from 0 to 50. In the case of a mixture of multiple compounds with different repeating numbers, the average value of n (Σn / Σ number of molecules) is in the range of 0 to 50. The preferred value of n or its average value varies depending on the intended application. For example, for applications such as semiconductor encapsulation, which require a high filler loading, a low viscosity is desirable, and the value of n or its average value is 0 to 15, preferably 0.1 to 10.0, and more preferably 0.1 to 5.0. Conventional epoxy resins are often obtained by a sequential reaction in which a compound with n = 0 is produced, which is then polymerized to produce a compound with n = 1. Such epoxy resins can also be advantageously used in the present invention. Furthermore, for applications such as printed wiring boards, high-molecular-weight epoxy resins are preferably used, and in this case the value of n is 2 to 50, preferably 5 to 50, and more preferably 10 to 40.

[0018] The weight-average molecular weight of the epoxy resin of the present invention is preferably in the range of 500 to 6,000, more preferably in the range of 500 to 3,000. The epoxy equivalent is preferably in the range of 300 to 3,000, more preferably in the range of 300 to 2,000, and particularly preferably in the range of 400 to 1,000. If it is greater than this, the viscosity and softening point become high, making it difficult to prepare the epoxy resin composition and reducing moldability. The softening point or melting point of the epoxy resin of the present invention is preferably in the range of 80 to 350°C, more preferably in the range of 100 to 300°C. The hydrolyzable chlorine content is preferably 1,000 ppm or less, more preferably 500 ppm or less.

[0019] The epoxy resin of the present invention can be produced by reacting a dihydroxy compound represented by general formula (1) with epichlorohydrin, although this reaction is not particularly limited. This reaction can be carried out in the same manner as a conventional epoxidation reaction.

[0020] For example, a dihydroxy compound represented by general formula (1) is dissolved in excess epichlorohydrin, followed by reaction in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide at 50 to 150°C, preferably 60 to 120°C, for 1 to 10 hours. The alkali metal hydroxide is used in an amount of 0.8 to 2 moles, preferably 0.9 to 1.2 moles, per mole of hydroxyl groups in the dihydroxy compound. Epichlorohydrin is used in excess relative to the hydroxyl groups in the dihydroxy compound, typically in an amount of 1.5 to 15 moles, preferably 2 to 8 moles, per mole of hydroxyl groups in the dihydroxy compound. A quaternary ammonium salt or the like can be added during the reaction. Examples of quaternary ammonium salts include tetramethylammonium chloride, tetrabutylammonium chloride, and benzyltriethylammonium chloride. The amount of the quaternary ammonium salt added is preferably 0.1 to 2.0 wt% relative to the dihydroxy compound. If the amount is less than this, the effect of adding the quaternary ammonium salt is small, and if it is more than this, the production of difficult-to-hydrolyze chlorine increases, making it difficult to achieve high purity. Furthermore, polar solvents such as dimethyl sulfoxide and diglyme may be used, and the amount added is preferably in the range of 10 to 200 wt% relative to the dihydroxy compound. If the amount is less than this, the effect of adding is small, and if it is more than this, the volume efficiency decreases, which is not economically preferable. After completion of the reaction, the excess epichlorohydrin is distilled off, and the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered, washed with water to remove inorganic salts, and then the solvent is distilled off to obtain the desired epoxy resin.

[0021] The epoxy resin composition of the present invention comprises an epoxy resin and a curing agent, and contains, as an epoxy resin component, an epoxy resin represented by general formula (2) or a dihydroxy compound represented by general formula (1) as an essential component.

[0022] When the epoxy resin represented by general formula (2) is used as an essential component, any curing agent generally known as an epoxy resin curing agent can be used. Examples include dicyandiamide, polyhydric phenols, acid anhydrides, aromatic and aliphatic amines, etc. Specific examples of polyhydric phenols include dihydric phenols such as bisphenol A, bisphenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, and naphthalenediol; trihydric or higher phenols such as tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolac, o-cresol novolac, naphthol novolac, and polyvinylphenol; and further, phenols, naphthols, bisphenol A, bisphenol B, bisphenol C, bisphenol D, bisphenol E, bisphenol F, bisphenol F, bisphenol F, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, and naphthalenediol. Examples of suitable phenolic compounds include polyhydric phenolic compounds synthesized by condensing dihydric phenols such as phenol F, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, resorcinol, and naphthalenediol with condensing agents such as formaldehyde, acetaldehyde, benzaldehyde, p-hydroxybenzaldehyde, and p-xylylene glycol. Examples of suitable acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhimic anhydride, nadic anhydride, and trimellitic anhydride. Examples of amines include aromatic amines such as 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, m-phenylenediamine, and p-xylylenediamine; aliphatic amines such as ethylenediamine, hexamethylenediamine, diethylenetriamine, and triethylenetetramine; and dihydroxy compounds represented by general formula (1). The resin composition of the present invention can contain one or more of these curing agents in combination. When the dihydroxy resin of the present invention is used as a curing agent, its amount is preferably 5 to 100 wt %, more preferably 30 to 100 wt %, of the total curing agent.

[0023] In addition to the epoxy resin represented by general formula (2), the epoxy resin composition of the present invention can also contain any conventional epoxy resin having two or more epoxy groups in the molecule. Examples include dihydric phenols such as bisphenol A, bisphenol S, fluorene bisphenol, 4,4'-biphenol, 2,2'-biphenol, hydroquinone, and resorcinol; trihydric or higher phenols such as tris-(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, phenol novolac, and o-cresol novolac; and glycidyl ethers derived from halogenated bisphenols such as tetrabromobisphenol A. These epoxy resins can be used alone or in combination. In this case, the amount of the epoxy resin represented by formula (2) of the present invention is preferably 5 to 100 wt %, more preferably 50 to 100 wt %, of the total epoxy resin.

[0024] As the epoxy resin in the case where the dihydroxy compound represented by the general formula (1) is used as an essential component, any ordinary epoxy resin having two or more epoxy groups in the molecule can be used.

[0025] In the epoxy resin composition of the present invention, a compound generally known as a curing agent for epoxy resins can also be used in combination with the dihydroxy compound represented by general formula (1), as described above.

[0026] The blending ratio of epoxy resin to curing agent is preferably in the range of 0.8 to 1.5 in terms of equivalent ratio of epoxy groups to functional groups in the curing agent. Outside this range, there is a possibility that unreacted epoxy groups or functional groups in the curing agent may remain after curing.

[0027] The epoxy resin composition of the present invention may contain oligomers or polymers such as polyesters, polyamides, polyimides, polyethers, polyurethanes, petroleum resins, indene coumarone resins, and phenoxy resins, as appropriate, and may also contain additives such as inorganic fillers, pigments, flame retardants, thixotropy-imparting agents, coupling agents, and flowability improvers. Examples of inorganic fillers include silica powders such as spherical or crushed fused silica and crystalline silica, alumina powders, glass powders, mica, talc, calcium carbonate, alumina, and hydrated alumina. Examples of pigments include organic or inorganic extender pigments and flake pigments. Examples of thixotropy-imparting agents include silicone-based agents, castor oil-based agents, aliphatic amide waxes, oxidized polyethylene waxes, and organic bentonite-based agents. Furthermore, if necessary, conventionally known curing accelerators can be used. Examples include amines, imidazoles, organic phosphines, Lewis acids, etc. The amount added is usually in the range of 0.2 to 5 parts by weight per 100 parts by weight of the epoxy resin. Furthermore, if necessary, the resin composition of the present invention may contain a release agent such as carnauba wax or OP wax, a coupling agent such as γ-glycidoxypropyltrimethoxysilane, a colorant such as carbon black, a flame retardant such as antimony trioxide, a stress reducer such as silicone oil, a lubricant such as calcium stearate, or the like.

[0028] The cured product of the present invention can be obtained by molding the above-mentioned epoxy resin composition by a method such as casting, compression molding, transfer molding, etc. The temperature during molding is usually in the range of 120 to 280°C. [Example]

[0029] The present invention will be specifically described below based on examples and comparative examples. Example 1 (Production of dihydroxy compound A) In a separable flask, 47.5 g of 4,4'-oxydiphthalic dianhydride and 50.3 g of 5-amino-1-naphthol were dissolved in 150 mL of N-methylpyrrolidone and reacted at 80°C for 2 hours. 75 mL of toluene was added to the reaction mixture, and the temperature was raised while removing the water generated by azeotropy. The temperature was then raised to 160°C and the reaction was continued for 3 hours. During this time, the water generated was removed from the system. After cooling to room temperature, 750 mL of distilled water was added, and the precipitate was collected by filtration, washed with water, and dried to obtain 84.0 g of a powdered product (dihydroxy compound A). The melting point of the resulting dihydroxy compound A was 211°C, and the hydroxyl equivalent was 306 g / eq. GPC analysis indicated a purity of 100%. The infrared absorption spectrum is shown in Figure 1. The melting point was measured using a Hitachi High-Tech Science DSC7020 differential scanning calorimeter, and the endothermic peak temperature measured at a heating rate of 10°C / min was taken as the melting point. The hydroxyl equivalent was measured by potentiometric titration with potassium hydroxide in an acetyl chloride solution. The infrared absorption spectrum was measured using a JASCO FT / IR-6100 infrared absorption analyzer by the KBr pellet method.

[0030] Example 2 (Production of dihydroxy compound B) A reaction similar to that in Example 1 was carried out using 45.0 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 50.3 g of 5-amino-1-naphthol in a separable flask, yielding 82.8 g of a powdery product (dihydroxy compound B). The melting point of the resulting dihydroxy compound B was 210°C, and the hydroxyl equivalent was 296 g / eq. GPC measurement revealed that the purity was 100%.

[0031] Example 3 (Synthesis of Epoxy Resin A) 20 g of dihydroxy compound A obtained in Example 1 was dissolved in 125 g of epichlorohydrin and 75 g of N-methylpyrrolidone, and 5.5 g of 48.6% aqueous sodium hydroxide solution was added dropwise over 4 hours at 65°C under reduced pressure (approximately 130 mmHg). During this time, the water produced was removed from the system by azeotropy with epichlorohydrin, and the distilled epichlorohydrin was returned to the system. After the reaction, epichlorohydrin was removed by distillation under reduced pressure, and the reaction solution was added dropwise to a large amount of distilled water. The product was filtered, washed with water, and dried to obtain 19 g of a yellowish-brown epoxy resin (epoxy resin A). The resulting epoxy resin had a melting point of 185°C, an epoxy equivalent of 362 g / eq., and a hydrolyzable chlorine content of 560 ppm. GPC analysis revealed that 89% of the general formula (2) was n=0 and 9% was n=1. The GPC measurement was performed using an apparatus: HLC-8320 (manufactured by Tosoh Corporation) and columns: two TSKgel SuperHZ2500 columns and two TSKgel SuperHZ2000 columns (both manufactured by Tosoh Corporation), with a solvent of tetrahydrofuran, a flow rate of 0.35 ml / min, a temperature of 40°C, and an RI detector. The infrared absorption spectrum is shown in Figure 2. The epoxy equivalent was measured by potentiometric titration with perchloric acid in a solution of tetraethylammonium bromide in acetic acid. Hydrolyzable chlorine was determined by dissolving 0.5 g of a resin sample in 30 ml of 1,4-dioxane, boiling and refluxing the solution in 5 ml of 1N KOH / methanol for 30 minutes, and then potentiometric titration with silver nitrate solution. 1 H-NMR measurements were performed using a JEOL RESONANCE JNM-ECA600 spectrometer and DMSO-d as the solvent. The measurement results are shown in Figure 3.

[0032] Example 4 (Synthesis of Epoxy Resin B) A reaction was carried out in the same manner as in Example 3 using 23 g of the dihydroxy compound B obtained in Example 2, 150 g of epichlorohydrin, 75 g of N-methylpyrrolidone, and 6.6 g of a 48.6% aqueous solution of sodium hydroxide, yielding 22 g of a brownish-white epoxy resin (epoxy resin B). The resulting epoxy resin had a melting point of 159°C, an epoxy equivalent of 347 g / eq., and a hydrolyzable chlorine content of 340 ppm. GPC analysis revealed that 88% of the compounds in formula (2) had n=0 and 11% had n=1.

[0033] Reference Example 1 (Production of Dihydroxy Compound C) Using 51.0 g of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 42.7 g of 4-amino-m-cresol, the same reaction as in Example 1 was carried out to obtain 81 g of a powdery product (dihydroxy compound C). GPC measurement revealed that the purity was 100%.

[0034] Reference Example 2 (Synthesis of Epoxy Resin C) Using 20 g of the dihydroxy compound C obtained in Reference Example 1, 180 g of epichlorohydrin, 90 g of N-methylpyrrolidone, and 6.5 g of a 48.6% aqueous solution of sodium hydroxide, a reaction was carried out in the same manner as in Example 3 to obtain 34 g of a brownish-white epoxy resin (epoxy resin C). The resulting epoxy resin had a melting point of 260°C and an epoxy equivalent of 328 g / eq.

[0035] Reference Example 3 (Production of dihydroxy compound D) Using 51.0 g of 4,4'-oxydiphthalic dianhydride and 40.5 g of 4-amino-m-cresol, the same reaction as in Example 1 was carried out to obtain 77 g of a powdery product (dihydroxy compound D). GPC measurement revealed that the purity was 100%.

[0036] Reference Example 4 (Synthesis of Epoxy Resin D) Using 15 g of dihydroxy compound D obtained in Reference Example 3, 105 g of epichlorohydrin, 30 g of N-methylpyrrolidone, and 4.4 g of 48.6% aqueous sodium hydroxide solution, a reaction was carried out in the same manner as in Example 3 to obtain 16 g of a brown epoxy resin (epoxy resin D). The resulting epoxy resin had a melting point of 170°C and an epoxy equivalent of 324 g / eq.

[0037] Examples 5 to 7 and Comparative Examples 1 to 3 The epoxy resins (epoxy resins A to D) synthesized in Examples 3 and 4 and Reference Examples 3 and 4, diphenyl ether epoxy resin (epoxy resin E: YSLV-80DE manufactured by Nippon Steel Chemical & Material Co., Ltd., epoxy equivalent weight 163, melting point 81°C), o-cresol novolac epoxy resin (epoxy resin F: EOCN-1020 manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent weight 200, softening point 55°C), the dihydroxy compound (curing agent A) synthesized in Example 1, and phenol novolac (curing agent B: BRG-557 manufactured by Aica Kogyo Co., Ltd., hydroxyl group equivalent weight 104, softening point 83°C) were used as curing accelerators. 1636678999873_0 The ingredients were weighed out in the formulation shown in Table 1 using a TMP, and mixed with stirring at 180°C to prepare a resin composition. This was used to mold (190°C, 5 minutes) in a press molding machine, and then post-cured (175°C, 4 hours) to obtain test pieces, which were then subjected to various physical property tests. The test methods were as follows. The results are shown in Table 1.

[0038] [evaluation] (1) Mixability The powder mixture was weighed out according to the formulation shown in Table 1, stirred and mixed at 180°C, and the state of the melted mixture was observed. The results were evaluated as follows: ◯: The epoxy resin and hardener were uniformly melted and mixed. △: A small amount of unmixed epoxy resin and hardener remained. ×: The epoxy resin and the curing agent were not uniformly melted, and unmixed portions remained. (2) Formability The resin composition was pulverized into powder, which was then charged into a mold heated to 190°C and press-molded. The surface condition of the molded test piece was visually observed. The evaluation was as follows: ◯: No unfilled areas in the mold. The surface of the molded product is smooth. △: There are unfilled areas in the four corners of the mold. The surface of the molded product is uneven. ×: Unfilled areas were found throughout the mold. Voids were generated throughout the molded product, resulting in a brittle molded product. (3) Linear expansion coefficient, glass transition temperature Measurements were carried out using a Hitachi High-Tech Science TMA7100 thermomechanical measuring device at a temperature rise rate of 10°C / min. (4) Thermal decomposition temperature, residual carbon rate Using a Hitachi High-Tech Science TG / DTA7300 thermogravimetric analyzer, the thermal decomposition temperature at 10 wt% weight loss and the residual carbon ratio at 700°C were determined under nitrogen flow at a heating rate of 10°C / min. (5) Water absorption rate A disk with a diameter of 50 mm and a thickness of 3 mm was molded, and after post-curing, it was left to absorb moisture for 100 hours under conditions of 85°C and a relative humidity of 85%, after which the weight change rate was recorded.

[0039] [Table 1]

Claims

1. The following general formula (2): 【Chemical 1】 (wherein X represents a single bond or —O—, A represents a naphthylene group which may have a substituent, and n represents a number from 0 to 50.) An epoxy resin characterized by being represented by the formula:

2. 10. An epoxy resin composition comprising an epoxy resin and a curing agent, wherein the epoxy resin according to claim 1 is blended as an epoxy resin component.

3. A cured product obtained by curing the epoxy resin composition according to claim 2.

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