JP5630133B2 - Cyanate ester compound and cured product thereof - Google Patents

Description

  The present invention relates to a cyanate ester compound, and further relates to a curable resin composition containing the compound and a cured product thereof. Such curable resin compositions are used for electrical insulating material resins, liquid crystal display panel sealing resins, liquid crystal color filter resins, resist resins, semiconductor sealing resins, printed wiring board adhesives, electrical It can be used for a wide range of applications such as laminates and prepreg build-up laminates, matrix resins of fiber reinforced composite materials, various paints, coating agents, and adhesives.

  Since fiber reinforced composite materials are lightweight and have high mechanical properties, their use is expanding as an alternative material to metal materials in structures such as aircraft, automobiles, sports and leisure goods. Along with this, various physical properties have been required for fiber reinforced composite materials, and the required properties include improved heat resistance and flame retardancy. Thermosetting resins such as phenolic resin, melamine resin, bismaleimide resin, unsaturated polyester resin, cyanate ester resin, and epoxy resin are used as a matrix resin for fiber-reinforced composite materials, depending on the application. The heat resistance and flame retardancy of the reinforced composite material largely depend on the physical properties of the matrix resin.

As an improvement in heat resistance, an epoxy resin obtained by glycidylating 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane or an epoxy resin having a triglycidylaminophenol skeleton as a main component. The composition which mix | blended diamino diphenyl sulfone, polyether sulfone, and polyetherimide with the epoxy resin to perform is disclosed (for example, refer patent document 2).
Further, cyanate ester resin produces a triazine ring upon curing, and has high elastic modulus and heat resistance. Therefore, it is preferable as the thermosetting resin, and a method for producing a fiber reinforced composite material using the cyanate ester resin as a matrix is also disclosed. (For example, see Patent Document 3 and Patent Document 4).
On the other hand, as an improvement in flame retardancy, use of an epoxy resin having a halogen or a monofunctional cyanate having a halogen is disclosed (for example, see Patent Document 5 and Patent Document 6).
However, since a resin composition containing such a flame retardant may generate a halogen-based gas that may cause environmental pollution during combustion or molding, a cyanate ester is used as a flame retardant instead of halogen. Studies are underway to introduce phosphorus and nitrogen atoms into compounds. Use of a cyanato group-containing phosphazene compound (for example, see Patent Document 7) and an isocyanuric acid skeleton-containing cyanate ester compound have been disclosed (for example, see Patent Document 8).
However, the heat resistance of the cured product using the above resin composition is about 280 ° C., which is not sufficient for the required performance in these application fields in recent years, and further improvement of physical properties is desired.

Japanese Patent No. 3573530 JP-A-62-297316 JP 2003-12819 A JP 2006-70115 A JP-A-2-286723 JP-A-6-122863 JP 2008-248066 A JP 2006-328286 A

  The present invention provides a novel cyanate ester compound having a cured product excellent in heat resistance and flame retardancy, a curable resin composition containing the compound, and a cured product obtained by curing the resin composition. There is to do.

As a result of intensive studies, the present inventors have found that the cyanate ester compound represented by the general formula (1) gives a cured product having excellent heat resistance, and have completed the present invention. . That is, the present invention is as follows.
1. A cyanate ester compound represented by the general formula (1).

(In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. R ² represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, Represents an alkoxy group having 1 to 4 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, or a cyanato group.)
2. R ¹ is any one selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group and a t-butyl group. The cyanate ester compound described in 1.
3. 1. R ² is hydrogen, methyl group, ethyl group, propyl group, isopropyl group, t-butyl group or cyanato group. Or 2. The cyanate ester compound described in 1.
4). 2. R ¹ is a methyl group. Or 3. The cyanate ester compound described in 1.
5. 1 above. ~ 4. A curable resin composition comprising the cyanate ester compound described in 1.
6). 5. above. Hardened | cured material formed by hardening | curing curable resin composition of description.
7). 5. above. A fiber-reinforced composite material obtained by impregnating a fiber base material with the curable resin composition described in 1.
8). 5. above. A sealing material comprising the curable resin composition described in 1.
9. 5. above. An adhesive comprising the curable resin composition described in 1.
10. 5. above. A prepreg impregnated with the curable resin composition described in 1.
11. 10 above. A laminate or metal-clad laminate obtained by curing the prepreg described in 1.
12 5. above. An insulating material comprising the curable resin composition described in 1.

  The cyanate ester compound of the present invention gives a cured product having high glass transition temperature and decomposition temperature and excellent flame retardancy by polymerizing itself or copolymerizing with other resins. Therefore, it is extremely useful as a functional polymer material, and as a material with excellent thermal properties, electrical insulation materials, adhesives, laminate materials, resists, build-up laminate materials, civil engineering / architecture, electrical / electronics, automobiles, It is preferably used as a fixing material, a structural member, a reinforcing agent, a shaping material, etc. in the fields of railways, ships, aircraft, sporting goods, arts and crafts. Among these, a wide range of aircraft structural members, satellite structural members and railway vehicle structural members that require weather resistance, flame retardancy and high mechanical strength, fiber reinforced composite materials for sports, that is, golf club shafts, fishing rods, etc. Can be used for applications.

¹ H-NMR chart of 2,4,6-tris (N-methyl-4-cyanatoanilino) 1,3,5-triazine obtained in Example 1 ¹ H-NMR chart of 2,4-bis (N-methyl-4-cyanatoanilino) -6- (N-methylanilino) 1,3,5-triazine obtained in Example 2

  The cyanate ester compound of the present invention is represented by the general formula (1).

(In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. R ² represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, Represents an alkoxy group having 1 to 4 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, or a cyanato group.)

R ¹ is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, or a t-butyl group because the melt viscosity of the resin composition is decreased (the lower the viscosity, the better the workability of the composition). A methyl group is particularly preferred because it can achieve both a decrease in melt viscosity of the resin composition and flame retardancy of the cured product.

R ² is preferably hydrogen, a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group or a cyanato group because a cured product having higher flame retardancy can be obtained. Among them, a cyanate group is preferably flame retardant. This is particularly preferable because a cured product having excellent heat resistance can be obtained.

  Although the manufacturing method of the compound represented by General formula (1) is not specifically limited, For example, the existing method can be mentioned as cyanate synthesis from the phenol described in General formula (2). In addition, the phenol described in the general formula (2) can be obtained by reacting cyanuric chloride with N-alkylaminophenol or N-arylaminophenol by a conventional method.

(In the formula, R ¹ is the same as formula (1).)

In the case of using this production method, R ¹ is determined by the N-alkylaminophenol or N-arylaminophenol used, for example, N-methyl-4-aminophenol, N-ethyl-4-aminophenol, 4-propylamino. Phenol, 4-isopropylaminophenol, 4-n-butylaminophenol, 4-isobutylaminophenol, p-anilinophenol, 4- (4-methylanilino) phenol or 4- [1] naphthylamino-phenol are used. be able to.
Among these, it is preferable for the above reason to use N-alkylaminophenol in which R ¹ is a methyl group, an ethyl group, a propyl group, an isopropyl group, or a t-butyl group.

In this production method, a compound represented by the general formula (1) in which R ² is a cyanato group can be obtained.

  As another method for obtaining the compound represented by the general formula (1), 2,4-dichloro-prepared beforehand by reacting cyanuric chloride with a predetermined amount of an aromatic secondary amine whose para-position is not a hydroxyl group is used. 6- (N-alkyl-N-arylamino) -1,3,5-triazine or 2,4-dichloro-6- (N-aryl-N-arylamino) -1,3,5-triazine is converted to N- The method of making it react with alkylaminophenol or N-arylaminophenol, obtaining the phenol represented by General formula (3), and cyanating a hydroxyl group is mentioned.

(In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. R ² represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, Represents an alkoxy group having 1 to 4 carbon atoms and an aryloxy group having 6 to 12 carbon atoms.)

In this production method, R ² is determined by an aromatic secondary amine in which the para-position used is not a hydroxy group, such as N-methylaniline, N-ethylaniline, Nn-propylaniline, N-isopropylaniline, Nt. -Butylaniline, N-methyl-p-toluidine, N-ethyl-p-toluidine, N-methyl-p-anisidine, 4- (methylamino) biphenyl, N-methyl-4-phenoxyaniline, etc. may be used. it can.
Among them, R ² is hydrogen, methyl group, ethyl group, propyl group, isopropyl group, t-butyl group, N-methylaniline, N-ethylaniline, Nn-propylaniline, N-isopropylaniline, N- It is preferred to use t-butylaniline.

  As a method of cyanating the compound represented by the general formula (2) or (3) obtained by the above method to obtain the compound represented by the general formula (1), for example, IAN HAMERTON, “Chemistry and Technology of Cyanate” The method described in “Ester Resins”, BLACKIE ACADEMIC & PROFESSIONAL can be used. U.S. Pat. No. 3,553,244 provides a method of reacting in a solvent in the presence of a base so that the cyanogen halide is always present in excess of the base. In JP-A-7-53497, a tertiary amine is used as a base, and a method of synthesizing while using it in excess of cyanogen halide is disclosed in JP-T-2000-501138 as a continuous plug flow method, and a trialkyl. JP-A-2001-504835 discloses a method of reacting an amine and a cyanogen halide. When a phenol and a cyanogen halide are reacted in a non-aqueous solution of tert-amine, a by-product tert-ammonium halide is converted into a cation and The method of treating with an anion exchanger is disclosed in Japanese Patent No. 299954 in the presence of a solvent capable of separating a phenol compound with water, and a tertiary amine and a cyanogen halide are added and reacted at the same time, followed by washing with water and separation. There is a method in which the obtained solution is purified by precipitation using a secondary or tertiary alcohol or a poor hydrocarbon solvent. Are mounting, it can be used any of these methods.

  Next, the curable resin composition of the present invention will be described. The curable resin composition contains the cyanate ester compound represented by the above formula (1), and is a cyanate ester compound other than the cyanate ester compound of the present invention, an epoxy resin. It is also possible to add an oxetane resin and / or a compound having a polymerizable unsaturated group.

  As a cyanate ester compound other than the cyanate ester compound, generally known compounds can be used. For example, bisphenol A dicyanate, bisphenol F dicyanate, bisphenol M dicyanate, bisphenol P dicyanate, bisphenol E dicyanate, phenol novolac cyanate, cresol novolac cyanate, dicyclopentadiene novolac cyanate, tetramethylbisphenol F dicyanate, biphenol dicyanate Can be mentioned. These cyanate ester compounds can be used alone or in combination.

  As the epoxy resin, generally known epoxy resins can be used. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, xylene novolac type epoxy resin, triglycidyl isocyanurate, alicyclic epoxy resin, dicyclo Examples thereof include pentadiene novolac type epoxy resins, biphenyl novolac type epoxy resins, phenol aralkyl novolac type epoxy resins, and naphthol aralkyl novolak type epoxy resins. These epoxy resins can be used alone or in combination.

  As the oxetane resin, generally known oxetane resins can be used. For example, oxetane, 2-methyloxetane, 2,2-dimethyloxetane, 3-methyloxetane, alkyloxetane such as 3,3-dimethyloxetane, 3-methyl-3-methoxymethyloxetane, 3,3′-di (tri Fluoromethyl) perfluoxetane, 2-chloromethyloxetane, 3,3-bis (chloromethyl) oxetane, OXT-101 (trade name, manufactured by Toagosei Co., Ltd.), OXT-121 (trade name, manufactured by Toagosei Co., Ltd.), etc. Is mentioned. These oxetane resins can be used alone or in combination.

  As the compound having a polymerizable unsaturated group, generally known compounds can be used. For example, vinyl compounds such as ethylene, propylene, styrene, divinylbenzene, divinylbiphenyl, methyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polypropylene glycol di (meth) acrylate, Mono- or polyhydric alcohol (meth) acrylates such as trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, bisphenol Epoxy (meth) acrylates such as A-type epoxy (meth) acrylate and bisphenol F-type epoxy (meth) acrylate, benzocyclobutene resin, (bis) male De resins. These compounds having an unsaturated group can be used alone or in combination.

  The curable resin composition of the present invention may contain a compound that catalyzes the polymerization of a cyanate ester, an epoxy resin, an oxetane resin, or a compound having a polymerizable unsaturated group. Examples of the polymerization catalyst include zinc octylate, zinc naphthenate, cobalt naphthenate, copper naphthenate, acetylacetone iron and the like, phenol compounds such as octylphenol and nonylphenol, alcohols such as 1-butanol and 2-ethylhexanol, 2 -Methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethyl Imidazole, imidazole derivatives such as 2-phenyl-4-methyl-5-hydroxymethylimidazole, dicyandiamide, benzyldimethylamine, amine compounds such as 4-methyl-N, N-dimethylbenzylamine, Epoxy-imidazole adducts such as “Amicure PN-23” manufactured by Ajinomoto Fine Techno Co., “Novacure HX-3721” manufactured by Asahi Kasei Co., Ltd., “Fujicure FX-1000” manufactured by Fuji Kasei Kogyo Co., Ltd., etc. Compounds, peroxides such as benzoyl peroxide, p-chlorobenzoyl peroxide, di-t-butyl peroxide, diisopropyl peroxycarbonate, di-2-ethylhexyl peroxycarbonate, or azo such as azobisisobutyronitrile Compounds and the like.

  An inorganic filler can be blended in the curable resin composition of the present invention. Inorganic fillers include silicates such as talc, calcined clay, unfired clay, mica and glass, oxides such as titanium oxide, alumina, silica and fused silica, carbonates such as calcium carbonate, magnesium carbonate and hydrotalcite. Salts, hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, sulfates or sulfites such as barium sulfate, calcium sulfate, calcium sulfite, zinc borate, barium metaborate, aluminum borate, calcium borate And borate salts such as sodium borate, nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride, and titanates such as strontium titanate and barium titanate. One of these can be used alone, or two or more can be used in combination. Among these, silica is particularly preferable, and fused silica is preferable in that it has excellent low thermal expansion. Further, although crushed and spherical silica exists, spherical silica is preferable in terms of lowering the melt viscosity of the resin composition.

  It is preferable that the spherical silica is further treated with a treatment agent for surface treatment in advance. The treating agent is preferably at least one compound selected from the group consisting of functional group-containing silanes, cyclic oligosiloxanes, organohalosilanes, and alkylsilazanes.

  Among the treatment agents, the surface treatment of the spherical silica using organohalosilanes and alkylsilazanes is suitable for hydrophobizing the silica surface, and the dispersion of the spherical silica in the resin composition It is preferable in terms of excellent properties.

  The functional group-containing silanes are not particularly limited. For example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3 , 4-epoxycyclohexyl) ethyldimethoxysilane, and other epoxysilane compounds, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyldi Mercaptosilanes such as (meth) acrylic silanes such as ethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropylmethyldimethoxysilane, vinyltrie Vinyl silanes such as xylsilane, vinyltrimethoxysilane, and vinyltrichlorosilane, isocyanate silanes such as 3-isocyanatopropyltriethoxysilane, ureidosilanes such as 3-ureidopropyltrimethoxysilane, and 3-ureidopropyltriethoxysilane, (5 (5-norbornen-2-yl) alkyl such as -norbornen-2-yl) trimethoxysilane, (5-norbornen-2-yl) triethoxysilane, and (5-norbornen-2-yl) ethyltrimethoxysilane Mention may be made of silane and phenylsilane such as phenyltrimethoxysilane.

  Silicone resin powder can be blended with the curable resin composition of the present invention. The silicone resin powder is a cured product powder having a structure in which a siloxane bond is cross-linked in a three-dimensional network represented by (RSiO3 / 2) n, and a powder having an average particle size of 0.1 to 10 μm is suitable. is there. Specifically, KMP-590 (made by Shin-Etsu Silicone), KMP-701 (made by Shin-Etsu Silicone), X-52-854 (made by Shin-Etsu Silicone), X-52-1621 (made by Shin-Etsu Silicone), XC99-B5664 (Momentive)・ Performance Materials), XC99-A8808 (Momentive Performance Materials), Tospearl 120 (Momentive Performance Materials), etc. It is also possible to use it.

  As a method for producing the curable resin composition of the present invention, a cyanate ester compound represented by the general formula (1) and, if necessary, various additives and a solvent are mixed with a known mixer such as a high-speed mixer or a nauter. It can be obtained by mixing using a mixer, ribbon type blender, mixing roll, kneader, intensive mixer, single screw extruder, twin screw extruder, universal mixer, dissolver, static mixer, and the like. In that case, the addition method of a cyanate ester compound, various additives, and a solvent is not specifically limited.

  The cured product of the present invention can be obtained by curing the curable resin composition of the present invention obtained by the above-described method with heat or light. After melting or dissolving the curable resin composition of the present invention in a solvent, it can be produced by pouring into a mold and curing under normal conditions. In the case of thermosetting, if the curing temperature is too low, curing does not proceed, and if it is too high, the cured product is deteriorated.

Moreover, a fiber reinforced composite material can be manufactured using the resin composition of the present invention.
The form and arrangement of the reinforcing fibers are not particularly limited, and can be appropriately selected from woven fabrics, nonwoven fabrics, mats, knits, braids, unidirectional strands, rovings, choppeds, and the like. In addition, a preform (a laminate of woven fabrics made of reinforcing fibers, or a structure in which these are stitched together with stitch yarn, or a fiber structure such as a three-dimensional woven fabric or a braid) is applied as a form of reinforcing fibers. You can also.
Specific examples of the method for producing a fiber reinforced composite material include a liquid composite molding method, a resin film infusion method, a filament winding method, a hand layup method, and a pultrusion method. Among them, the resin transfer molding method, which is one of the liquid composite molding methods, can set materials other than the above-described preforms such as metal plates, foam cores, and honeycomb cores in the mold in advance. Since it can be applied to various applications, it is preferably used when a composite material having a relatively complicated shape is mass-produced in a short time.

  Moreover, a sealing material can be manufactured using the resin composition of this invention. The method for producing the sealing material is not particularly limited, and the components containing the above-described resin composition are uniformly mixed with a mixer, a blender or the like, and then kneaded with a roll or a kneader. There is no restriction | limiting in particular in the mixing | blending order of a component.

  Moreover, an inorganic and / or organic fiber base material prepreg can be manufactured using the resin composition of this invention. The manufacturing method of a prepreg is not specifically limited, The well-known method used for printed wiring material is applicable. For example, a method in which a resin composition varnish is impregnated into an inorganic and / or organic fiber base material, dried and B-staged to obtain a prepreg can be applied.

  Moreover, the resin composition of this invention can be used for manufacture of a metal-clad laminated board and a multilayer board. A manufacturing method is not specifically limited, A laminated board can be obtained by heat-press-molding what laminated | stacked the above-mentioned prepreg and metal foil. Although the temperature to heat is not specifically limited, 65-300 degreeC is preferable and 120-270 degreeC is especially preferable. Moreover, the pressure to pressurize is not particularly limited, but is preferably 2 to 5 MPa, and particularly preferably 2.5 to 4 MPa.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not particularly limited to the following examples. In addition, the glass transition temperature of the hardened | cured material and the decomposition temperature were evaluated by the following method.

(1) Glass transition temperature (Tg): In accordance with JIS-K7244-7-2007, using a dynamic viscoelasticity measuring device (“AR2000” manufactured by TA Instruments Inc., start temperature 100 ° C., end temperature The identification viscoelasticity measurement was carried out at 400 ° C., a heating rate of 3 ° C./min, and a measurement frequency of 1 Hz, and the maximum value of the loss tangent (tan δ) obtained at that time was defined as the glass transition temperature. It can be said that it is excellent in heat resistance.
(2) Decomposition temperature: In accordance with JIS-K7120, using a differential thermothermal gravimetric simultaneous measurement device (manufactured by SII NanoTechnology Co., Ltd., RTG-220) at a heating rate of 10 ° C./min under a nitrogen stream. Thermogravimetry was performed, and the temperature at which the weight decreased by 5% from the start of measurement was taken as the decomposition temperature. It can be said that the higher the decomposition temperature, the better the heat resistance.
(3) Flame resistance: A flame resistance test was performed based on UL94. However, the test piece was 10 mm × 70 mm × 1.5 mm.

Synthesis Example 1 Synthesis of 2,4,6-tris (N-methyl-4-hydroxyanilino) -1,3,5-triazine (abbreviated as TMHT-OH) N-methyl-4-aminophenol (J. Org) Chem., 2003, 68 (19), pp 7374-7378, prepared from 4-aminophenol and dimethyl carbonate 20.0 g (162.7 mmol) of N-methylpyrrolidone (Wako Pure Chemical Industries, Ltd.) Manufactured) and dissolved in 100 mL, and cooled to 5 ° C. Next, 10.0 g (54.2 mmol) of cyanuric chloride (manufactured by Wako Pure Chemical Industries, Ltd.) was added in portions. After the addition, the temperature was raised to 100 ° C., and the mixture was heated and stirred for 14 hours.
After cooling the reaction solution, it was poured into 900 mL of a 1.5% aqueous sodium hydroxide solution, and the insoluble matter was filtered off. The filtrate was neutralized with 1 mol / L hydrochloric acid, and the precipitated crystals were collected by filtration. The obtained crystals were washed with 500 mL of purified water and recrystallized with chloroform-ethanol to obtain 18.6 g of the target TMHT-OH. The structure was identified by NMR spectrum. 1H-NMR: (400 MHz, dimethyl sulfoxide-d6, internal standard TMS)
δ (ppm) 3.22 (s, 9H), 6.66 (d, 6H), 7.05 (d, 6H), 9.26 (s, 3H)

Synthesis Example 2 Synthesis of 2,4-dichloro-6- (N-methyl-N-phenylamino) -1,3,5-triazine 10.0 g (54.2 mmol) of cyanuric chloride was dissolved in 40 mL of tetrahydrofuran, and 0 ° C. Cooled to. There, N-methylaniline (made by Wako Pure Chemical Industries Ltd.) 5.81g (54.2mmol) and the tetrahydrofuran solution 18g were dripped at 0-5 degreeC, and it stirred at 0 degreeC after dripping for 2 hours.
20 g of an aqueous solution of 2.87 g (27.1 mmol) of sodium carbonate was added dropwise and stirred for 1 hour. After stirring, the reaction solution was concentrated under reduced pressure to 40 g, and 80 mL of chloroform was added to the resulting residue to separate the organic phase. The obtained organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain a crude product.
The obtained composition was dissolved by heating in a mixed solvent of 25 mL of toluene and 65 mL of hexane, filtered after hot and cooled. The precipitated crystals are collected by filtration, washed with hexane, and dried under reduced pressure to obtain 12.7 g of 2,4-dichloro-6- (N-methyl-N-phenylamino) -1,3,5-triazine. It was. The structure was identified by NMR spectrum.
1H-NMR: (400 MHz, chloroform-d, internal standard TMS)
δ (ppm) 3.55 (s, 3H), 7.22 (d, 2H), 7.35 (m, 1H), 7.45 (m, 2H)

Synthesis Example 3 Synthesis of 2,4-bis (N-methyl-4-hydroxyanilino) -6- (N-methylanilino) -1,3,5-triazine (abbreviated as BMHT-OH) N-methyl-4- 9.66 g (78.4 mmol) of aminophenol was dissolved in 50 mL of N-methylpyrrolidone. 10.0 g (39.2 mmol) of 2,4-dichloro-6- (N-methyl-N-phenylamino) -1,3,5-triazine prepared in Synthesis Example 2 was added in portions at room temperature. After the addition, the temperature was raised to 100 ° C., followed by stirring with heating for 14 hours.
After cooling the reaction solution, it was poured into 450 mL of a 1.5% aqueous sodium hydroxide solution, and the insoluble matter was filtered off. The filtrate was neutralized with 1 mol / L hydrochloric acid, and the precipitated crystals were collected by filtration. The obtained crystals were washed with 300 mL of purified water and recrystallized with ethyl acetate to obtain 9.1 g of the target BMHT-OH. The structure was identified by NMR spectrum. 1H-NMR: (400 MHz, dimethyl sulfoxide-d6, internal standard TMS)
1H-NMR: (400 MHz, dimethyl sulfoxide-d6, internal standard TMS)
δ (ppm) 3.26 (m, 9H), 6.67 (d, 4H), 7.06 (d, 4H), 7.07 (t, 1H), 7.22-7.31 (m, 4H), 9.27 (s, 2H)

Synthesis Example 4 Synthesis of Tris (3,5-dimethyl-4- cyanatobenzyl) isocyanurate (abbreviated as TDHICN) Tris (3,5-dimethyl-4-hydroxybenzyl) isocyanurate (TDHI manufactured by Nippon Steel Chemical Co., Ltd.) .34 mol and 1.12 mol triethylamine were dissolved in 1260 g of 3-methyltetrahydrofuran (solution 1). Solution 1 was added dropwise to 414.96 g of 1.58 mol of cyanogen chloride in methylene chloride at −10 ° C. over 2 hours. After stirring for 30 minutes, 0.56 mol of triethylamine was added dropwise and the mixture was further stirred for 30 minutes to complete the reaction. After the triethylamine hydrochloride was filtered off, the obtained filtrate was washed with 1000 mL of 0.2N hydrochloric acid, and then washed with 1000 ml of 5% aqueous sodium chloride solution three times and once with 1000 mL of water. After drying with sodium sulfate, it was evaporated at 75 ° C. to obtain 216 g of yellowish white solid crystals. The obtained crystal was again dissolved in 130 g of tetrahydrofuran at 95 ° C., and then recrystallized. The obtained crystals were washed with 300 ml of n-hexane and then dried under reduced pressure to obtain 173 g (TDHICN) of tris (3,5-dimethyl-4-cyanatobenzyl) isocyanurate as yellowish white crystals. It was confirmed by infrared absorption spectrum measurement and melting point that the cyanate ester compound thus obtained was tris (3,5-dimethyl-4-cyanatobenzyl) isocyanurate.

Synthesis Example 5 Synthesis of Cyanato Group-Containing Phosphazene [Step 1: Production of Cyclic Phosphononitrile Substituted Product ]
Under a nitrogen stream, hexachlorocyclotriphosphazene (86.9 g, 0.75 unit mol) was charged into a 1 liter four-necked flask equipped with a thermometer, stirrer, condenser and dropping funnel, and chlorobenzene (MCB, 581 g). To dissolve. A solution of sodium phenoxide (87 g, 0.75 mol) in tetrahydrofuran (THF, 160 g) was slowly added dropwise over 5 hours, and the mixture was stirred at 25 ° C. for 24 hours. The obtained reaction solution was added to a MCB (813 g) suspension of 4-hydroxybenzaldehyde potassium salt (140.5 g, 0.975 mol) prepared in advance, and then tetrabutylammonium bromide (1.5 g, 0.0047 mol). Was added and refluxed at 110 ° C. for 3 hours. After cooling the reaction mixture to room temperature, 5% aqueous sodium hydroxide solution (700 g), water (100 g), and MCB (111 g) were added, and the mixture was transferred to a separatory funnel. After separating the aqueous layer, the MCB layer was washed twice with a 2% aqueous sodium hydroxide solution (500 g), neutralized with dilute nitric acid, and washed with water. The MCB layer was concentrated under reduced pressure to obtain 187.7 g (yield: 96.5%) of the product.
[Step 2: Production of cyanato group-containing phosphazene by condensation step of cyclic phosphonitrile substituted product and phenol]
The compound obtained in Step 1 (187.1 g, 0.241 mol), phenol (274.5 g, 2.89 mol), MCB (in a 2 liter four-necked flask equipped with a thermometer, a stirrer, and a condenser tube, 1,327 g) and p-toluenesulfonic acid (5.92 g, 0.028 mol) were added and stirred at 60 ° C. for 2 hours. Thereafter, a dehydrator (Dean Stark) was attached, and the mixture was further heated to 130 ° C., and the generated water was removed from the system. After completion of the reaction, the mixture was cooled to room temperature, 4-methyl-2-pentanone (MIBK, 801 g) was added, and the mixture was washed with water three times. After the MIBK layer was concentrated under reduced pressure, the concentrated residue was crystallized with a methanol-water mixed solvent to obtain 232 g (yield 75%) of a red product. The obtained product was subjected to NMR and elemental analysis, and [N ₃ = P ₃ (OC ₆ H ₄ CHO) (OC ₆ H ₅ ) ₅ ], [N ₃ = P ₃ (OC ₆ H ₄ CHO) ₂ ( _{OC 6 H 5) 4],} [N 3 = P 3 (OC 6 H 4 CHO) 3 (OC 6 H 5) 3], [N 3 = P 3 (OC 6 H 4 CHO) 4 (OC 6 H 5 ) ₂ ], and it was confirmed that the average composition was [N ₃ = P ₃ (OC ₆ H ₄ CHO) _2.7 (OC ₆ H ₅ ) _3.3 ].

Example 1 Synthesis of 2,4,6-tris (N-methyl-4-cyanatoanilino) -1,3,5-triazine (abbreviated as TMHT-CN) 15.0 g of TMHT-OH prepared in Synthesis Example 1 (33 0.7 mmol) and 17.6 g (222.8 mmol) of triethylamine were dissolved in 100 mL of tetrahydrofuran (solution 1). Chloroform 21.5g (202.5mmol) chloroform 135mL was cooled at -10 degreeC, and the solution 1 was dripped there over 1.5 hours. After stirring for 30 minutes and confirming the completion of the reaction, the reaction solution was washed with 0.2 mol / L hydrochloric acid and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to obtain 17.9 g of a solid. It was. The obtained solid was rewashed with n-hexane to obtain 16.7 g of the target TMHT-CN. The structure was identified by NMR spectrum (FIG. 1).
1H-NMR: (400 MHz, chloroform-d, internal standard TMS)
δ (ppm) 3.35 (s, 9H), 7.21 (d, 6H), 7.32 (d, 6H)

Example 2 Synthesis of 2,4-bis (N-methyl-4-cyanatoanilino) -6- (N-methylanilino) -1,3,5-triazine (abbreviated as BMHT-CN) Synthesis instead of TMHT-OH The same procedure as in Example 1 was performed except that BMHT-OH prepared in Example 3 was used. The structure of the obtained crystal was identified by NMR spectrum (FIG. 2).
1H-NMR: (300 MHz, chloroform-d6, internal standard TMS)
δ (ppm) 3.37 (s, 9H), 7.16-7.35 (m, 13H)

Example 3
100 parts by weight of TMHT-CN obtained in Example 1 was heated and melted and degassed with a vacuum pump, and a glass plate (120 mm × 120 mm × 5 mmt), a polyimide film (Kapton 200H: manufactured by Toray DuPont Co., Ltd.), made of fluoro rubber It was cast into a mold produced with an O-ring (S-100: manufactured by Mori Seika Co., Ltd.) and cured by heating in an oven at 250 ° C. for 4 hours. After cooling, the polyimide film was removed by polishing to obtain a cured product. About the obtained hardened | cured material, the glass transition temperature, the decomposition temperature, and the flame retardance were evaluated. The evaluation results of physical properties are shown in Table 1.

Example 4
It carried out similarly to Example 3 except having used 100 weight part of BMHT-CN obtained in Example 2 instead of using 100 weight part of TMHT-CN.

Example 5
Instead of using 100 parts by weight of TMHT-CN, it was carried out in the same manner as in Example 3 except that 55 parts by weight of TMHT-CN and 45 parts by weight of bisphenol A type cyanate (abbreviated as DCBA, manufactured by Mitsubishi Gas Chemical Co., Ltd.) were used.

Example 6
The same procedure as in Example 3 was performed except that 77 parts by weight of BMHT-CN and 23 parts by weight of DCBA were used instead of 100 parts by weight of TMHT-CN.

Comparative Example 1
The same procedure as in Example 3 was performed except that 100 parts by weight of DCBA was used instead of 100 parts by weight of TMHT-CN.

Comparative Example 2
The same procedure as in Example 3 was performed except that 100 parts by weight of TDHICN synthesized in Synthesis Example 4 was used instead of 100 parts by weight of THMT-CN.

Comparative Example 3
The same procedure as in Example 3 was performed except that 100 parts by weight of the cyanate-containing phosphazene synthesized in Synthesis Example 5 was used instead of 100 parts by weight of THMT-CN.

* The unit of blending amount is parts by weight, and the description part of “-” means that the corresponding raw material is not blended.

* 1 Cyanate ester compound obtained in Example 1 * 2 Cyanate ester compound obtained in Example 2 * 3 Cyanate ester compound obtained in Synthesis Example 4 * 4 Cyanate obtained in Synthesis Example 5 Ester compound

  From Table 1, the hardened | cured material of Examples 3-6 had a high glass transition temperature and decomposition temperature compared with Comparative Examples 1-3, and became the result excellent in heat resistance and a flame retardance.

Claims (12)

A cyanate ester compound represented by the general formula (1).
(In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. R ² represents hydrogen, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Represents an alkoxy group having 1 to 4 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, or a cyanato group.) 2. The cyanate ester compound according to claim 1, wherein R ¹ is any one selected from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, and a t-butyl group. The cyanate ester compound according to claim 1 or 2, wherein R ² is hydrogen, a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, or a cyanato group. The cyanate ester compound according to claim 2 or 3, wherein R ¹ is a methyl group. A curable resin composition comprising the cyanate ester compound according to claim 1. Hardened | cured material formed by hardening | curing curable resin composition of Claim 5. A fiber reinforced composite material obtained by impregnating a fiber base material with the curable resin composition according to claim 5. A sealing material comprising the curable resin composition according to claim 5. An adhesive comprising the curable resin composition according to claim 5. A prepreg impregnated with the curable resin composition according to claim 5. Laminate or metal-clad laminate obtained by curing the prepreg according to claim 10. An insulating material comprising the curable resin composition according to claim 5.