JP7480945B2 - Monoglycidyl ether having a mesogenic skeleton and composition thereof - Google Patents

Description

The present invention relates to a monoglycidyl ether having a mesogenic skeleton and a composition containing the monoglycidyl ether.

When designing epoxy resin compositions for use as electrical and electronic materials, it has been known that monofunctional or polyfunctional glycidyl ethers are blended as reactive diluents to be incorporated into the cured product, because the bisphenol A epoxy resins, bisphenol F epoxy resins, and biphenyl epoxy resins commonly used as base materials are so viscous or solid that they are difficult to handle at the work site. In addition, among such monofunctional glycidyl ethers, those having aromatic rings are also known to impart heat dissipation properties that allow them to be used as electrical and electronic materials.

For example, Patent Document 1 discloses that, among the monofunctional glycidyl ethers to be blended with bifunctional glycidyl ethers having aromatic rings, such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, and biphenyl type epoxy resins, phenyl glycidyl ethers and the like can be blended as those having aromatic rings.

JP 2004-75835 A

Patent Document 1 discloses phenyl glycidyl ethers having aromatic rings as reactive diluents that are monofunctional glycidyl ethers that can be blended with bifunctional glycidyl ethers having aromatic rings, such as bisphenol A epoxy resins and biphenyl epoxy resins, but there is a demand for monofunctional glycidyl ethers with even better heat dissipation properties.

The present invention aims to provide a monofunctional glycidyl ether and a composition containing the same that can ensure workability at the work site compared to bifunctional glycidyl ethers having aromatic rings, such as bisphenol A epoxy resins, bisphenol F epoxy resins, and biphenyl epoxy resins, which are commonly used as base resins, and can give a cured product with better heat dissipation properties.

（式中、窒素原子は芳香環のオルト位、メタ位又はパラ位のいずれかに結合しており、 Ｘは、Ｈ、ＣＮ、Ｆ、Ｃｌ、Ｂｒ、Ｉ、メトキシ基、エトキシ基から選ばれる１種であ る。）
で表されるメソゲン骨格を有するモノグリシジルエーテルと、

（Ｘはハロゲン原子またはＣ１～Ｃ５のアルキル基、ａおよびｂは置換基Ｘの個数であ って０～４の整数、ＲはＣ１からＣ１０のアルキレン基、アルキリデン基、カルボニル 基、スルホニル基、酸素原子又は原子団の存在しない直接結合を示す。）
で表される芳香環を有するジグリシジルエーテルとを有し、前記モノグリシジルエーテ ルの配合割合が３０重量％以上であることを特徴とするエポキシ樹脂組成物である。 [1] That is, the present invention provides

(In the formula, the nitrogen atom is bonded to the ortho-, meta- or para-position of the aromatic ring, and X is one selected from H, CN, F, Cl, Br, I, a methoxy group and an ethoxy group.)
and a monoglycidyl ether having a mesogenic skeleton represented by the formula:

(X is a halogen atom or a C1-C5 alkyl group, a and b are the number of X substituents and are integers from 0 to 4, and R is a C1 to C10 alkylene group, alkylidene group, carbonyl group, sulfonyl group, or a direct bond that does not contain an oxygen atom or atomic group.)
and a diglycidyl ether having an aromatic ring represented by the following formula :

[ 2 ] And, there is provided an epoxy resin cured product obtained by curing the epoxy resin composition according to the above [ 1 ] with at least one curing agent selected from amines, acid anhydrides, and phenols.

According to the present invention, it is possible to ensure workability at the work site for bifunctional glycidyl ethers having aromatic rings, such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, and biphenyl type epoxy resins, which are commonly used as base resins, and to give cured products with superior heat dissipation properties.

Polarizing microscope photographs of the cured products of Example 1 and Comparative Example 1

The following is a detailed description of embodiments of the monoglycidyl ether having a mesogenic skeleton and a composition thereof according to the present invention. Note that when a range is indicated in the description, it includes an upper limit and a lower limit.

（式中、窒素原子は芳香環のオルト位、メタ位又はパラ位のいずれかに結合しており、Ｘは、Ｈ〔水素〕、ＣＮ〔シアノ基〕、Ｆ〔フッ素〕、Ｃｌ〔塩素〕、Ｂｒ〔臭素〕、Ｉ〔ヨウ素〕、メトキシ基、エトキシ基から選ばれる１種である。） In the present invention, the monoglycidyl ether having a mesogen skeleton, which is a rigid portion that exhibits liquid crystallinity, is a monoglycidyl ether represented by the chemical formula of Chemical 1. By using the monoglycidyl ether represented by the chemical formula of Chemical 1, when it is mixed with a bifunctional glycidyl ether having an aromatic ring, such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, or a biphenyl type epoxy resin, which is commonly used as a base resin, it is possible to obtain a cured product with excellent heat dissipation properties by stabilizing the arrangement in a stacked manner by interacting with the aromatic ring contained in the base epoxy resin. In addition, when the base epoxy resin is a biphenyl type epoxy resin, the workability is not favorable because the melting point of the biphenyl type epoxy resin is high at about 156°C, but since the compound represented by the chemical formula of Chemical 1 is a monoglycidyl ether, the melting point is considerably lower than that of the highly symmetrical biphenyl type epoxy resin, by mixing the compound represented by the chemical formula of Chemical 1 to several tens of weight percent, the melting point of the epoxy resin composition can be lowered by several tens of degrees, thereby improving the workability.

(In the formula, the nitrogen atom is bonded to the ortho-, meta- or para-position of the aromatic ring, and X is one selected from H (hydrogen), CN (cyano group), F (fluorine), Cl (chlorine), Br (bromine), I (iodine), a methoxy group, and an ethoxy group.)

As described above, in the monoglycidyl ether represented by the chemical formula of Chemical Formula 1, the nitrogen atom is bonded to any one of the ortho, meta or para positions of the aromatic ring, the monoglycidyl ether represented by the chemical formula of Chemical Formula 1 includes monoglycidyl ether represented by the chemical formula of Chemical Formula 3 in which the nitrogen atom is bonded to the para position of the aromatic ring, monoglycidyl ether represented by the chemical formula of Chemical Formula 4 in which the nitrogen atom is bonded to the meta position of the aromatic ring, and monoglycidyl ether represented by the chemical formula of Chemical Formula 5 in which the nitrogen atom is bonded to the ortho position of the aromatic ring. In the monoglycidyl ethers represented by the chemical formulas of Chemical Formula 3, Chemical Formula 4 and Chemical Formula 5, X is the same as in Chemical Formula 1.

Specific examples of the compound represented by formula 3 include 4-benzylideneaminophenol glycidyl ether, 4-4'-cyanobenzylideneaminophenol glycidyl ether, 4-4'-fluorinated benzylideneaminophenol glycidyl ether, 4-4'-chlorinated benzylideneaminophenol glycidyl ether, 4-4'-brominated benzylideneaminophenol glycidyl ether, 4-4'-iodinated benzylideneaminophenol glycidyl ether, 4-4'-methoxybenzylideneaminophenol glycidyl ether, and 4-4'-ethoxybenzylideneaminophenol glycidyl ether.

In Chemical formula 4, specifically, 3-benzylideneaminophenol glycidyl ether, 3-4'-cyanobenzylideneaminophenol glycidyl ether, 3-4'-fluorinated benzylideneaminophenol glycidyl ether, 3-4'-chlorinated benzylideneaminophenol glycidyl ether, 3-4'-brominated benzylideneaminophenol glycidyl ether, 3-4'-iodinated benzylideneaminophenol glycidyl ether, 3-4'-methoxybenzylideneaminophenol glycidyl ether, and 3-4'-ethoxybenzylideneaminophenol glycidyl ether are preferred.

In Chemical formula 5, specifically, 2-benzylideneaminophenol glycidyl ether, 2-4'-cyanobenzylideneaminophenol glycidyl ether, 2-4'-fluorinated benzylideneaminophenol glycidyl ether, 2-4'-chlorinated benzylideneaminophenol glycidyl ether, 2-4'-brominated benzylideneaminophenol glycidyl ether, 2-4'-iodinated benzylideneaminophenol glycidyl ether, 2-4'-methoxybenzylideneaminophenol glycidyl ether, and 2-4'-ethoxybenzylideneaminophenol glycidyl ether are preferred.

The monoglycidyl ethers of Chemical 3, Chemical 4, and Chemical 5 contained in Chemical 1 can be used alone or in combination. In addition, the specific compounds contained in the monoglycidyl ethers of Chemical 3, Chemical 4, and Chemical 5 can be used alone or in combination. For example, 4-benzylideneaminophenol glycidyl ether and 4-4'-cyanobenzylideneaminophenol glycidyl ether in Chemical 3 can be used in combination.

Diglycidyl ether, represented by the chemical formula 2, is a bifunctional glycidyl ether with an aromatic ring, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and biphenyl type epoxy resin, which are commonly used as base resins.

Specific examples of diglycidyl ethers represented by the chemical formula 2 include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, halogenated bisphenol A type epoxy resins, halogenated bisphenol F diglycidyl ether, halogenated bisphenol S diglycidyl ether, 4,4'-biphenyldiylbis(glycidyl ether) (hereinafter referred to as 4,4'-biphenyl diglycidyl ether), and 3,3',5,5'-tetramethylbiphenyl-4,4'-diylbis(glycidyl ether). Among these, 4,4'-biphenyldiylbis(glycidyl ether) is more preferred because it can give a cured product with excellent heat dissipation properties.

The epoxy resin composition of the present invention is a composition containing a monoglycidyl ether represented by the chemical formula of Chemical Formula 1 and a diglycidyl ether represented by the chemical formula of Chemical Formula 2. The monoglycidyl ether represented by the chemical formula of Chemical Formula 1 is preferably contained in the epoxy resin composition at 30% by weight or more, more preferably 35 to 65% by weight, and most preferably 40 to 60% by weight. When the proportion of the monoglycidyl ether represented by the chemical formula of Chemical Formula 1 is within this range, workability can be ensured at the work site, and the epoxy resin composition has a temperature range in which it exhibits liquid crystallinity, thereby providing a cured product with excellent heat dissipation properties.

At least one selected from amines, acid anhydrides, and phenols can be used as a curing agent for the above-mentioned epoxy resin composition. These curing agents undergo a chemical reaction with the epoxy resin composition under heating conditions, etc., to form a cured product with a three-dimensional network structure.

Specific examples of amines that can be used as curing agents include diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), m-xylenediamine (MXDA), trimethylhexamethylenediamine (TMD), 2-methylpentamethylenediamine (2-MPMDA), diethylaminopropylamine (DEAPA), isophoronediamine (IPDA), 1,3-bisaminomethylcyclohexane (1,3-BAC), bis(4-aminocyclohexyl)methane (PACM), norbornenediamine (NBDA), 1,2-diaminocyclohexane (1,2-DCH), 4,4'-diaminodiphenylmethane (DDM), metaphenylenediamine (MPDA), diaminodiphenylsulfone (DDS), and N-aminoethylpiperazine (N-AEP). Of these, 4,4'-diaminodiphenylmethane (DDM) is more preferred because it can give a cured product with excellent heat dissipation properties.

Specific examples of acid anhydrides that can be used as curing agents include phthalic anhydride (PA), hexahydrophthalic anhydride (HHPA), tetrahydrophthalic anhydride (THPA), methyltetrahydrophthalic anhydride (Me-THPA), maleic anhydride, succinic anhydride (SA), dodecynylsuccinic anhydride (DDSA), methylnadic anhydride (NMA), pyromellitic anhydride (PMDA), methylhexahydrophthalic anhydride (Me-HHPA), and trimellitic anhydride (TMA). Of these, phthalic anhydride (PA) is more preferred because it can give a cured product with excellent heat dissipation properties.

Specific examples of phenols that can be used as hardeners include bisphenol A (BPA), hydroquinone (HQ), resorcinol (RES), bisphenol F (BPF), biphenol (BIP), tetrabromobisphenol A (TBBA), naphthalene diol, phenol novolac resin, and cresol novolac resin.

The above-mentioned curing agents can be used alone or in combination of two or more. The blending ratio of the cured product is preferably 0.3 to 1.2 equivalents per equivalent of epoxy group of the epoxy resin blended with the monoglycidyl ether represented by the chemical formula 1 and the dimonoglycidyl ether represented by the chemical formula 2. More preferably, it is 0.5 to 1.1 equivalents. This makes it possible to obtain a cured product with appropriate mechanical strength without causing uncured parts.

In addition to the above components, a curing accelerator can be added to the epoxy resin cured product of the present invention in advance, as long as the physical properties of the cured product are not impaired. By adding this curing accelerator, the curing speed can be increased, thereby improving productivity.

Compounds that can be used as hardening accelerators are not particularly limited, but include 2-ethyl-4-methylimidazole (2E4MZ), 2-phenylimidazole, 1-(2- Examples of known compounds include imidazoles such as 2E4MZ-CN, 2,4-diamino-6-[2-methylimidazolyl-(1)]ethyl-s-triazine, 2MZ-A, 2-phenylimidazoline, 2PZL, and 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, tris(dimethylaminomethyl)phenol, benzyldimethylamine, and tertiary amines such as DBU, organic phosphine compounds such as triphenylphosphine, tertiary amine salts, quaternary ammonium salts, phosphonium salts, and metal salts such as tin octylate. These accelerators are appropriately selected based on the requirements for the resin composition, such as the time required for curing and pot life.

If necessary, colorants, antioxidants, leveling agents, surfactants, UV absorbers, silane coupling agents, inorganic fillers, resin particles, wettability improvers, etc. can be added to the curing accelerator in advance to the epoxy resin composition or curing agent.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

Example 1
As the monoglycidyl ether, 8.90 g (32 mmol) of 4-benzylideneaminophenol glycidyl ether (component A1 in Table 1) and 4.05 g (16 mmol) of 4-4'-cyanobenzylideneaminophenol glycidyl ether (component A2 in Table 1) were used, and as the diglycidyl ether, 15.51 g (52 mmol) of 4,4'-biphenyl diglycidyl ether was used, which were pulverized in an agate mortar and uniformly dispersed, and melted and degassed for 5 minutes on a hot plate at 135°C to obtain an epoxy resin composition. Then, 7.48 g of 4,4'-diaminodiphenylmethane (corresponding to an amine equivalent number that is 0.5 times the epoxy equivalent of the epoxy resin composition) was mixed with the epoxy resin composition, and the mixture was uniformly mixed on a hot plate at 135°C. Thereafter, the mixture of the epoxy resin composition and 4,4'-diaminodiphenylmethane was placed in a heating device and heated at 70°C for 2 hours, at 80°C for 2 hours, at 90°C for 2 hours, at 100°C for 2 hours, and at 110°C for 2 hours to obtain a final cured product.

<Comparative Example 1>
A final cured product was obtained in the same manner as in Example 1, except that 7.87 g (48 mmol) of m,p-cresyl glycidyl ether, which is a mixture of m-cresyl glycidyl ether and p-cresyl glycidyl, was used as the monoglycidyl ether.

The thermal conductivity of these cured products was measured to examine their heat dissipation. Thermal conductivity is a value that indicates the ease of heat flow within a substance, and is measured by a steady-state method in which a steady unidirectional heat flow is created in the target material and measured, or a non-steady-state method in which the target material is heated non-steadily, the temperature change over time is measured, and the thermal conductivity is calculated from the obtained values such as thermal diffusivity. Of these, the non-steady-state method, which has various measurement methods such as the laser flash method, is preferred. Using the laser flash method, which is a non-steady-state method, the thermal conductivity (W/m·k) was measured twice each using a thermal conductivity measuring device (manufactured by NETZSCH, product number: LFA447NanoFlash) that calculates thermal conductivity from the thermal diffusivity, specific heat capacity, and density of the cured product, and the average thermal conductivity was calculated. The higher the thermal conductivity value, the easier it is to transfer heat and the better the heat dissipation.

The compounding compositions and performances for Example 1 and Comparative Example 1 are shown in Table 1.

Figure 1 shows polarizing microscope photographs of the cured products of Example 1 and Comparative Example 1. The scale is as shown in each photograph.

As shown in Table 1, it was confirmed that the thermal conductivity of the cured product of the epoxy resin composition was significantly improved by using 4-benzylideneaminophenol glycidyl ether (component A1 in Table 1) and 4-4'-cyanobenzylideneaminophenol glycidyl ether (component A2 in Table 1) as the monoglycidyl ether, compared to the system using m,p-cresyl glycidyl ether, and it was found that the heat dissipation was superior. This is thought to be because the aromatic rings in the monoglycidyl ethers 4-benzylideneaminophenol glycidyl ether (component A1 in Table 1) and 4-4'-cyanobenzylideneaminophenol glycidyl ether (component A2 in Table 1) interact with the aromatic rings of the monoglycidyl ether and amines, stacking each aromatic ring to make it more stable. Another major factor is that the monoglycidyl ether is more mobile during the curing process when heat is applied, and is more likely to interact with the aromatic rings of the monoglycidyl ether and amines. This is supported by the fact that, as shown in the polarizing microscope photograph in Figure 1, anisotropy due to a partially crystallized structure is observed in the cured product of Example 1, whereas no anisotropy is observed at all in the cured product of Comparative Example 1.

In this way, by using monoglycidyl ethers represented by the chemical formula 1, which include compounds such as 4-benzylideneaminophenol glycidyl ether (component A1 in Table 1) and 4-4'-cyanobenzylideneaminophenol glycidyl ether (component A2 in Table 1), it is possible to ensure workability at the work site for bifunctional glycidyl ethers having aromatic rings, such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, and biphenyl type epoxy resins, which are commonly used as base resins, and it has been found that a cured product with excellent heat dissipation properties can be obtained, which has been found to be useful in fields such as electrical and electronic materials, where heat dissipation is required.

Claims (2)

(In the formula, the nitrogen atom is bonded to the ortho-, meta- or para-position of the aromatic ring, and X is one selected from H, CN, F, Cl, Br, I, a methoxy group and an ethoxy group.)
and a monoglycidyl ether having a mesogenic skeleton represented by the formula:

(X is a halogen atom or a C1-C5 alkyl group, a and b are the number of X substituents and are integers from 0 to 4, and R is a C1 to C10 alkylene group, alkylidene group, carbonyl group, sulfonyl group, or a direct bond that does not contain an oxygen atom or atomic group.)
and a diglycidyl ether having an aromatic ring represented by the formula:
An epoxy resin composition comprising the monoglycidyl ether in an amount of 30% by weight or more. The epoxy resin composition according to claim 1 ,
A cured epoxy resin product cured with at least one curing agent selected from amines, acid anhydrides, and phenols.