JP2019189539A - Heat base generator, curable composition, and cured article - Google Patents

Abstract

To provide a heat base generator high in light stability and stability around room temperature, and sufficiently functioning as a curing catalyst of a heat curable compound after heating, a curable composition containing the heat base generator and a cured article of the curable composition.SOLUTION: There is provided a cinnamic acid amide type heat base generator represented by the following general formula (1). In the general formula (1), Rand Rform a heterocycle having aromatic property together with a neighboring nitrogen atom, Rand Rare each independently a hydrogen atom, a halogen atom, or a monovalent organic group, Rto Rare each independently a group or an atom other than a hydrogen group and a group generating a phenolic hydroxyl group by heating.SELECTED DRAWING: None

Description

  The present invention relates to a thermal base generator, a curable composition, and a cured product.

  Conventionally, a thermosetting resin composition containing a thermal base generator is known as a thermosetting material for an insulating layer of an electronic component.

  As a thermal base generator that can be used for such a thermosetting resin composition, for example, Patent Document 1 proposes a 2-hydroxycinnamic acid amide derivative having a specific structure. Patent Document 1 discloses that by including a 2-hydroxycinnamic acid amide derivative having a specific structure, the storage stability is good, and a polymer cured product can be obtained after heating. However, Non-Patent Document 1 reports that a 2-hydroxycinnamic amide derivative releases a base by light irradiation, and has a problem that it is unstable to light.

Japanese Patent No. 5768348

J Polym. Sci. A Polym. Chem. 2015, 53 p.1174-1177

  Accordingly, an object of the present invention is to include a thermal base generator, which has high light stability and stability near room temperature, and functions sufficiently as a curing catalyst for a thermosetting compound after heating, and the thermal base generator. An object is to provide a curable composition and a cured product of the curable composition.

  In the case of a structure that generates a base of an aromatic heterocyclic compound such as imidazole, the inventors of the thermal base generator described in Patent Document 1 have a potential to be eliminated because the base will be eliminated immediately. I found it difficult to grant. Therefore, the present inventors have conducted further studies in view of the above, and as a result, found that the cause is due to the hydroxyl group (that is, phenolic hydroxyl group) possessed by the benzene ring of cinnamic acid amide. It has been found that a structure in which a ring does not have a hydroxyl group is suitable for generating a base of an aromatic heterocyclic compound by heating and can solve the above problems, and the present invention has been completed.

（一般式（１）中、Ｒ^１およびＲ^２は隣接する窒素原子と共に、芳香性を有する複素環を形成し、Ｒ^３およびＲ^４は、それぞれ独立に、水素原子、ハロゲン原子、または一価の有機基であり、Ｒ^５〜Ｒ^９は、それぞれ独立に、水酸基および加熱でフェノール性水酸基を生成する基以外の基または原子である。） That is, the cinnamic amide type thermal base generator of the present invention is characterized by being represented by the following general formula (1).

(In General Formula (1), R ¹ and R ² together with the adjacent nitrogen atom form an aromatic heterocyclic ring, and R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, or a monovalent And R ^{5 to} R ⁹ are each independently a group or an atom other than a hydroxyl group and a group that generates a phenolic hydroxyl group by heating.)

The cinnamic amide-type thermal base generator of the present invention is characterized in that, in general formula (1), R ¹ and R ² together with the adjacent nitrogen atom form an imidazole ring.

  The curable composition of the present invention comprises the cinnamate amide type thermal base generator and a thermosetting compound.

  The cured product of the present invention is obtained by curing the curable composition.

  According to the present invention, a thermal base generator that has high photostability and stability near room temperature and that functions sufficiently as a curing catalyst for a thermosetting compound after heating, and curability containing the thermal base generator A composition and a cured product of the curable composition can be provided.

（一般式（１）中、Ｒ^１およびＲ^２は隣接する窒素原子と共に、芳香性を有する複素環を形成し、Ｒ^３およびＲ^４は、それぞれ独立に、水素原子、ハロゲン原子、または一価の有機基であり、Ｒ^５〜Ｒ^９は、それぞれ独立に、水酸基および加熱でフェノール性水酸基を生成する基以外の基または原子である。）ここで、有機基とは、炭素原子を有する基を意味する。 The cinnamic amide type thermal base generator of the present invention has a structure represented by the following general formula (1).

(In General Formula (1), R ¹ and R ² together with the adjacent nitrogen atom form an aromatic heterocyclic ring, and R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, or a monovalent R ^{5 to} R ⁹ are each independently a group or an atom other than a hydroxyl group and a group that generates a phenolic hydroxyl group by heating.) Here, the organic group is a group having a carbon atom. Means.

In the cinnamic acid amide type thermal base generator of the present invention, the aromatic heterocycle formed by R ¹ and R ² together with the adjacent nitrogen atom is eliminated by heating to generate a base.

The aromatic heterocyclic ring formed by R ¹ and R ² together with the adjacent nitrogen atom is not particularly limited as long as it exhibits basicity, and may be a monocyclic ring or a condensed ring, such as an imidazole ring or a triazole ring. , Indole ring, isoindole ring, purine ring, pyrazole ring, indazole ring, pyrrole ring and the like. Among these, a single ring is preferable.

The aromatic heterocyclic ring formed by R ¹ and R ² together with the adjacent nitrogen atom may have a substituent as long as the effects of the present invention are not impaired. Examples of the substituent include an alkyl group, an aryl group, an aralkyl group, an amino group, and a cyano group.

Examples of the halogen atom that R ³ and R ⁴ can take include fluorine, chlorine, bromine, iodine and the like.

Examples of the monovalent organic group that R ³ and R ⁴ can take include, for example, an alkyl group (preferably 1 to 12 carbon atoms), a cycloalkyl group (preferably 3 to 6 carbon atoms), and an aryl group (preferably Hydrocarbon group such as 6 to 10 carbon atoms, aralkyl group (preferably 6 to 14 carbon atoms), alkoxy group, acyl group, carboxyl group, alkoxycarbonyl group, carboxylate group, acyloxy group, carbamoyl group, thio A carbamoyl group, a cyano group, an isocyano group, a cyanato group, an isocyanato group, a thiocyanato group, an isothiocyanato group, a hydroxyimino group, and the like can be given. The hydrocarbon group may be saturated or unsaturated.

  The organic group may contain a bond other than hydrocarbon, for example, an ether bond, an ester bond, an amide bond, a urethane bond, a carbonyl bond, a carbonate bond, a sulfonyl bond, a sulfinyl bond, an imino bond, a thioether bond, a thiol bond, Examples include a carbonyl bond and an azo bond.

  The organic group may have a substituent, for example, a halogen atom such as fluorine, chlorine, bromine or iodine, an alkoxy group, a carboxyl group, a carboxylate group, an alkoxycarbonyl group, an alkyl ether group, an aryl ether group. , Amino group, carboxyl group, carboxylate group, acyl group, acyloxy group, nitro group, nitroso group, hydroxyimino group, carbamoyl group, thiocarbamoyl group, alkylthioether group, arylthioether group, mercapto group, sulfo group, sulfide group , Sulfino group, sulfonate group, cyano group, isocyano group, cyanato group, isocyanato group, thiocyanato group, isothiocyanato group, phosphino group, phosphinyl group, phosphono group, phosphonate group, silyl group, silanol group and the like. The hydrogen contained in the substituent may be substituted with a hydrocarbon group.

R ³ and R ⁴ are preferably a hydrogen atom, an alkyl group or an aryl group. More preferably, it is a hydrogen atom.

R ^{5 to} R ⁹ are not particularly limited as long as they are other than a hydroxyl group and a group that generates a phenolic hydroxyl group by heating, and examples thereof include a hydrogen atom, a halogen atom, and a monovalent organic group.

The halogen atoms include the same atoms and halogen atoms R ³ and R ⁴ can be taken.

Examples of the monovalent organic group include the same groups as the monovalent organic groups that R ³ and R ⁴ can take.

R ^{5 to} R ⁹ may be a substituent other than a monovalent organic group, and as such a substituent, a monovalent organic group that can be taken by R ³ and R ⁴ may have. And the halogen atoms and nitro groups exemplified above.

Two or more of R ^{5 to} R ⁹ may be bonded to form a cyclic structure, and the cyclic structure may include a hetero atom bond. As the cyclic structure, for example, a benzene ring in the general formula (1) shares an atom, and condensed hydrocarbon rings such as naphthalene ring, indene ring, anthracene ring, phenanthrene ring, fluorene ring, xanthene ring, thioxanthone A condensed heterocyclic ring such as a ring and a 1,3-benzodioxole ring.

  In addition, the group which produces | generates a phenolic hydroxyl group by heating is a group which thermally decomposes at 190 degrees C or less, and produces | generates a phenolic hydroxyl group, for example, although 2-propenyloxy group etc. are mentioned, it is not limited to this.

R ^{5 to} R ⁹ are preferably a hydrogen atom, an alkoxy group (preferably 1 to 8 carbon atoms), or an alkyl group (preferably 1 to 12 carbon atoms).

  The cinnamic acid amide type thermal base generator of the present invention preferably has no phenolic hydroxyl group.

  Specific examples of the cinnamic amide type thermal base generator of the present invention are shown below, but the present invention is not limited thereto.

  The method for synthesizing the cinnamic acid amide type thermal base generator of the present invention is not particularly limited, and may be synthesized using a known and commonly used method. For example, a method of condensing a corresponding cinnamic acid and a base using a condensing agent such as 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, a cinnamic acid and a base using a halogenating agent such as thionyl chloride , A method in which an acylated product of a base and a corresponding benzaldehyde derivative are subjected to aldol condensation, a method in which cinnamic acid is allowed to act on carbonyldiimidazole, and the like.

  The cinnamic amide-type thermal base generator of the present invention can generate a base of an aromatic heterocyclic compound containing a nitrogen atom by heating to 80 to 200 ° C., depending on the molecular structure.

  The purpose of use of the cinnamic amide type thermal base generator of the present invention is not particularly limited. For example, you may use as a hardening accelerator of thermosetting compounds, such as an epoxy compound, and you may provide thermosetting by mix | blending with the system by which hardening reaction is started by a base. You may use for not only a hardening reaction but various chemical reactions controlled by heating. In addition to the chemical reaction, the base itself may be used for the purpose.

  The industrial field in which the cinnamate amide type thermal base generator of the present invention is used is not particularly limited. For example, electronic parts, adhesives, paints, printing inks, coating materials, molding materials, pattern forming materials, building materials, optical parts It can be widely used for semiconductor devices, display devices, pharmaceuticals, cosmetics, agricultural chemicals and the like.

  If an example is given as an electronic component, formation of the cured film and sealing material of an electronic component will be mentioned. Examples of the cured film of the electronic component include a cured film of a printed wiring board such as a solder resist, an interlayer insulating layer, and a coverlay. Moreover, you may use for filling materials, such as a through hole of a printed wiring board, and a via hole. Moreover, you may use for a conductive adhesive. The electronic component may be an application other than the printed wiring board, for example, a passive component such as an inductor.

  The curable composition of the present invention comprises the cinnamate amide type thermal base generator of the present invention and a thermosetting compound. The cinnamic amide type thermal base generator of the present invention can be used alone or in combination of two or more.

  A thermosetting compound is not specifically limited, What is necessary is just to use a well-known and usual thing, For example, the compound which has an epoxy group, an isocyanate group, an oxetane group, or a thiirane group, a polysiloxane precursor, a polyimide precursor etc. are mentioned. A thermosetting compound can be used individually by 1 type or in combination of 2 or more types.

  Examples of the compound having an epoxy group include a bifunctional epoxy compound having two epoxy groups in the molecule, and a polyfunctional epoxy compound having many epoxy groups in the molecule. Note that a hydrogenated epoxy compound may be used.

  Examples of the compound having an epoxy group include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, Phenol novolac type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, biphenyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, fat Cyclic epoxy resin, aliphatic chain epoxy resin, phosphorus-containing epoxy resin, anthracene type epoxy resin, norbornene type epoxy resin, adamantane type epoxy resin, fluorene Type epoxy resins, aminophenol type epoxy resin, amino cresol type epoxy resin, alkylphenol type epoxy resin or the like is used.

  The compound having an epoxy group may be any of a solid epoxy resin, a semi-solid epoxy resin, and a liquid epoxy resin.

  In the curable composition of the present invention, the amount of the cinnamic amide type thermal base generator of the present invention is not particularly limited, but is preferably 0.1 to 20% by mass.

  In the curable composition of the present invention, the compounding amount of the thermosetting compound is preferably 10 to 99.9% by mass, although the compounding amount varies depending on the application.

  You may mix | blend a well-known and usual component with the curable composition of this invention. For example, curing accelerators such as melamine and dicyandiamide; inorganic fillers such as silica; organic fillers; conductive particles; thermoplastic resins; polymer resins; elastomers; organic binders; alkali-soluble resins such as carboxyl group-containing resins; , Compounds having an ethylenically unsaturated group such as a photopolymerizable oligomer; photopolymerization initiators, photoacid generators, photobase generators and other photosensitizers; photoinitiator assistants; sensitizers; cross-linking agents; Organic solvent; Wetting and dispersing agent; Thermal polymerization inhibitor; Ultraviolet absorber; Silane coupling agent; Plasticizer; Flame retardant; Antistatic agent; Anti-aging agent; Antioxidant; Antibacterial / antifungal agent; Examples include agents, thickeners, adhesion imparting agents, thixotropic agents, mold release agents, surface treatment agents, dispersants, dispersion aids, surface modifiers, stabilizers, and phosphors.

  The curable composition of the present invention is thermosetting, but various components may be blended to impart photosensitivity and photocurability.

(Production Example 1) Synthesis of cinnamic acid amide type thermal base generator In a 300 mL two-necked flask, trans-2-methoxycinnamic acid (2.17 g, 12.2 mmol), 1- [3- (dimethylamino) propyl]- 3-Ethylcarbodiimide hydrochloride (2.81 g, 14.6 mmol) was added, and the system was replaced with N _2, and then dry THF (80 mL) was added. After stirring at room temperature for 30 minutes, imidazole (1.00 g, 14.6 mmol) was added and stirred at room temperature overnight. The solvent was distilled off from the resulting reaction solution under reduced pressure, followed by extraction with chloroform, and the resulting organic layer was further dip. HCl, NaHCO ₃ aq. Washed with. After drying the organic layer with MgSO ₄ , the solvent was distilled off under reduced pressure to obtain a crude product. The product was purified by silica gel column chromatography (chloroform / methanol, 100: 1) to obtain a thermal base generator (1) (1.42 g, yield 51%) represented by the following chemical formula.

(Thermal base generator (1))

Production Example 2 Synthesis of Cinnamic Acid Amide Type Thermal Base Generator In Production Example 1, 2,4-dimethoxycinnamic acid (3.50 g, 16.8 mmol) was used instead of trans-2-methoxycinnamic acid. -[3- (dimethylamino) propyl] -3-ethylcarbodiimide hydrochloride (3.87 g, 20.2 mmol), similar to Production Example 1 except that the amount of imidazole (1.38 g, 20.2 mmol) was changed Thus, a thermal base generator (2) (2.94 g, yield 68%) represented by the following chemical formula was obtained.

(Thermal base generator (2))

(Production Example 3) Synthesis of Cinnamic Acid Amide Type Thermal Base Generator In Production Example 2, 2,5-dimethoxycinnamic acid (3.50 g, 16.8 mmol) was used instead of 2,4-dimethoxycinnamic acid. In the same manner as in Production Example 2, a thermal base generator (3) represented by the following chemical formula (3.51 g, yield 81%) was obtained.

(Thermal base generator (3))

(Production Example 4) Synthesis of cinnamic acid amide type thermal base generator Production Example 2 was produced except that 2-methylcinnamic acid (2.73 g, 16.8 mmol) was used instead of 2,4-dimethoxycinnamic acid. In the same manner as in Example 2, a thermal base generator (4) (2.20 g, yield 62%) represented by the following chemical formula was obtained.

(Thermal base generator (4))

(Production Example 5) Synthesis of cinnamic amide type thermal base generator Production Example 2 except that trans-cinnamic acid (2.49 g, 16.8 mmol) was used instead of 2,4-dimethoxycinnamic acid in Production Example 2. In the same manner as in No. 2, a thermal base generator (5) represented by the following chemical formula (2.06 g, yield 62%) was obtained.

(Heat base generator (5))

(Reference Production Example 1) Synthesis of Cinnamic Acid Amide Type Base Generator In order to synthesize a cinnamic acid amide type base generator in which the benzene ring represented by the following chemical formula has a hydroxyl group, The synthesis was carried out in the same manner as in Production Example 2 except that trans-2-hydroxycinnamic acid (2.49 g, 16.8 mmol) was used instead of cinnamic acid, but the result of 1H NMR analysis of the solution after the reaction No product was produced, and it was found that trans-2-hydroxycinnamic acid was converted to coumarin represented by the following chemical formula.

(Object)

(Coumarin)

(Comparative Production Example 1) Synthesis of Comparative Cinnamic Acid Amide Compound (1) In a 300 mL 2-necked flask, trans-2-methoxycinnamic acid (3.00 g, 16.8 mmol), 1- [3- (dimethylamino) propyl ] -3-Ethylcarbodiimide hydrochloride (3.87 g, 20.2 mmol) was added, and the system was replaced with N _2, and then dry THF (100 mL) was added. After stirring at room temperature for 30 minutes, piperidine (2.0 mL, 20 mmol) was added and stirred at room temperature overnight. The solvent was distilled off from the resulting reaction solution under reduced pressure, followed by extraction with chloroform (50 mL × 3), and the resulting organic layer was further dip. HCl, NaHCO ₃ aq. Washed with. After drying the organic layer with MgSO ₄ , the solvent was distilled off under reduced pressure to obtain a cinnamic acid amide compound (1) for comparison (2.57 g, yield 62%) represented by the following chemical formula.

(Cinamic acid amide compound (1) for comparison)

<1> Photostability test of cinnamic amide type thermal base generator For each 6 wt% NMP solution of thermal base generators (1) to (5), irradiation light from a mercury lamp equipped with an i-line filter was used. 20 J · cm ⁻² exposure. This solution was diluted in heavy acetone and subjected to 1H NMR measurement to calculate the ratio of the detached base. As a result, the ratio of the detached base was 0% in all cases.

<2> Storage stability evaluation of resin composition For epoxy resin (epoxy equivalent 189 manufactured by jER828 Mitsubishi Chemical), thermal base generators (1) to (5), cinnamic amide compound (1) or imidazole for comparison, 1-methyl-2-pyrrolidone was added and mixed with stirring so that the viscosity was about 200 mPa · s with respect to the epoxy group. The varnish was heated at 30 ° C. for 24 hours, and the ratio of the viscosity after heating for 24 hours to that before heating was measured to evaluate the storage stability. Those having a viscosity ratio of less than 150% were evaluated as ◯, those having a viscosity ratio of 150% or more as x, and the obtained results are shown in Table 1.

<3> Thermosetting evaluation of resin composition The resin composition prepared as described above was applied on a copper foil with a coating thickness of 25 μm. The coating film obtained by heating this coating film at 200 ° C. for 45 minutes was rubbed with a Kim wipe soaked with ethanol to evaluate thermosetting. The result obtained when the coating film did not elute into ethanol and there was no change in appearance due to scraping, and the coating film eluted into ethanol and the coating film disappeared from the copper foil by scraping was evaluated as x. Is shown in Table 1.

＊：熱塩基発生剤も比較用化合物も配合せず

*: No thermal base generator or comparative compound

From the results shown in <1> and Table 1 above, the cinnamic amide-type thermal base generator of the present invention has high photostability and stability near room temperature, and after heating, the thermosetting compound It turns out that it functions sufficiently as a curing catalyst.

Claims (4)

A cinnamic amide type thermal base generator represented by the following general formula (1):

(In General Formula (1), R ¹ and R ² together with the adjacent nitrogen atom form an aromatic heterocyclic ring, and R ³ and R ⁴ are each independently a hydrogen atom, a halogen atom, or a monovalent And R ^{5 to} R ⁹ are each independently a group or an atom other than a hydroxyl group and a group that generates a phenolic hydroxyl group by heating.) ^2. The cinnamic amide thermal base generator according to claim 1, wherein R ¹ and R ² in the general formula (1) form an imidazole ring together with the adjacent nitrogen atom.   A curable composition comprising the cinnamic acid amide type thermal base generator according to claim 1 or 2 and a thermosetting compound. A cured product obtained by curing the curable composition according to claim 3.