JPH0254369B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a curable resin composition that provides a heat-resistant resin containing a cyclized polymer of a polyfunctional α-ketonitrile compound of insulating material heat-resistant category C class (commonly used at 180° C. or higher). BACKGROUND ART In recent years, as electrical equipment such as rotating electric machines has become larger in capacity, smaller and lighter in weight, there has been a demand for thermosetting resin compositions with extremely excellent heat resistance. It is already known from US Pat. No. 3,775,380 that polyisocyanurate containing a cyanurate ring as a main structural unit has excellent heat resistance. This polycyanurate is expressed by the formula (1)
As shown in , it is obtained by trimerization (cyclization polymerization) reaction of a polyfunctional nitrile compound. Since the reaction of formula (1) is an addition reaction that does not involve the production of volatile matter, the cured product does not contain voids inside and is considered suitable as a highly heat-resistant insulating material. By the way, in order to cause this curing reaction by trimerization, Brønstedt acids such as sulfuric acid, p-toluenesulfonic acid, m-xylenesulfonic acid, trifluorosulfonic acid, and trichlorosulfonic acid, boron trifluoride, and anhydrous dichloride are generally used. tin, boron trifluoride amine complex, organometallic compound,
It is necessary to add a catalyst such as organic amine oxide. When the former Brønsted acid is used as a catalyst, the reaction proceeds sufficiently even at room temperature, but when the cured product is kept at a high temperature of 200°C or higher, the remaining curing catalyst acts as a catalyst for the decomposition reaction. Therefore, it has the drawbacks of poor heat resistance and impaired electrical properties. On the other hand, when boron trifluoride, boron trifluoride amine complex salts, organometallic compounds, organic amine oxides, etc. are used as catalysts, it is necessary to heat them at a temperature of 250°C or higher for three days or more in order to fully cure them. There is. Although the obtained cured product exhibits good heat resistance and electrical properties, it is not practical because curing requires such a high temperature and a long time. By the way, the trimerization reaction of nitrile compounds is thought to proceed according to the mechanism shown in formula (2), taking a monofunctional model compound as an example. Therefore, it is thought that when an electron-withdrawing group is placed adjacent to a nitrile group, the positive carbonium carbon of the nitrile group is further activated and the trimerization reaction of the nitrile group proceeds easily. Electron-withdrawing groups include atoms such as oxygen -O-, sulfur -S-, nitrogen -N-, or carbonyl groups.

[Formula] can be considered. Among these, -O-CN, -S-CN, and -NR-CN are known to easily trimerize into cyanurate. However, α-ketonitrile

The trimerization reaction of [Formula] is not known. G.BLACK is slightly like a polymer made from α-ketonitrile.
STOCK by J.Amer Chem.Soc., 34 , 1080
(1912). That is, when terephthaloyl chloride and hydrogen cyanide are reacted in a pyridine solvent, a brown powder that melts at around 300°C is obtained. However, this powder has poor heat resistance and poor electrical properties and cannot be used as an electrical insulating material. Therefore, the present inventors conducted extensive studies on the trimerization reaction of terephthaloyl cyanide. As a result, they discovered that the reaction of formula (3) can easily occur at relatively low temperatures, leading to the present invention. That is, an object of the present invention is to provide a novel heat-resistant resin suitable as, for example, an electrical insulating material. Its characteristics are the formula 1,3,5-triazine-2,4,6 represented by
-In resins containing a tolucarbonyl structure. This resin is obtained by polymerizing a polyfunctional α-ketonitrile compound in the presence of a cyanurate ring-forming catalyst. In the present invention, the polyfunctional α-ketonitrile compound is not particularly limited as long as it is a compound containing at least two α-ketonitrile groups in one molecule. Such compounds include, for example,
Phthaloyl cyanide, isophthaloyl cyanide,
Terephthaloyl cyanide, α,α′,α″-trioxo-1,2,5-benzenetriacetonitrile,
α, α′, α″, α-tetraoxo-1,2,4,
5-Benzenetetraacetonitrile, 4,4'-methylenebis(α-oxo-benzeneacetonitrile), 4,4'-propanediylbis(α-oxo-benzeneacetonitrile), 4,4'-sulfonylbis(α-oxo- benzeneacetonitrile),
4,4'-oxybis(α-oxo-benzeneacetonitrile), 4,4'-[(1-methyl-1,1-
ethanediyl)bis(4,1-phenyleneoxy)]bis[α-oxo-benzeneacetonitrile]. Furthermore, 4,4'-[(1-methyl-1,1-ethanediyl)bis(4,1-phenyleneoxy)]bis[α,α'-dioxo-1,2
-benzeneacetonitrile] is useful. These polyfunctional α-ketonitrile compounds may be used alone or in combination of two or more. In obtaining the heat-resistant resin of the present invention by polymerizing the α-ketonitrile compound as described above,
A cyanurate ring-forming catalyst plays an important role. Such catalysts include boron trifluoride, anhydrous stannic chloride, anhydrous aluminum chloride, anhydrous ferric chloride,
Lewis acids such as phosphorus pentachloride, cupric chloride, titanium tetrachloride, boron trifluoride amine complexes such as boron trifluoride monoethylamine complex salt, boron trifluoride piperidine complex salt, boron trifluoride imidazole complex salt, general formula (In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁶ represent hydrogen, an alkyl group, an alkenyl group, a phenyl group, or a substituted phenyl group, and R ⁵ represents a phenyl group or a substituted phenyl group. represents nitrogen, phosphorus, arsenic, antimony, or bismuth). In addition, Ziegler-Natsuta catalysts such as titanium tetrachloride-triethylaluminum, titanium tetrachloride-triisobutylaluminum, ferrous ferrocyanide, ferric ferrocyanide, copper ferrocyanide, zinc ferrocyanide, sodium ferrocyanide, potassium ferrocyanide , calcium ferricyanide, barium ferricyanide, lithium ferricyanide, ferrous ferricyanide, ferric ferricyanide, copper ferricyanide, sodium ferricyanide, potassium ferricyanide, calcium ferricyanide, magnesium ferricyanide, lithium ferricyanide, etc. metal ferricyanide, tin tetraphenyl, dibutyltin sulfide, tributyltin acrylate, triphenyltin chloride, hexabutylditin, dibutyldivinyltin, triethyltin chloride, tetraethyltin, dibutyltin diacetate, dioctyltin malate, triphenyltin hydroxide, Organic tin compounds such as tetravinyltin, organic antimony compounds such as tributylantimony, tributylantimony oxide, triphenyl antimony, triphenyl antimony sulfide, organic lead compounds such as tetraphenyl lead, organic mercury such as phenylmercury acetate, diphenylmercury, etc. compounds, organic arsenic compounds such as triphenyl arsenic, triphenyl arsenic oxide, organic iron compounds such as ferrocene (dicyclopentadienyl iron), chloromercury ferrocene, acetylferrocene, 1,1-bis(chloromercuryuro)ferrocene, Bis(cyclopentadienyl) titanium dichloride, tetra(i-propyl) titanate,
Tetra(n-butyl) titanate, tetrastearyl titanate, tetra(2-ethylhexyl)
Organic titanium compounds such as titanate, butyl titanate dimer, polymerized tetrabutyl titanate, bis(cyclopentadienyl) zirconium chloride, tetraethyl zirconate, tetra(i-
propyl) zirconate, tetra(n-butyl)
Organic zirconium compounds such as zirconate, tetra(n-pentyl)zirconate, tetra(n-hexyl)zirconate, tetra(n-octyl)zirconate, triphenylphosphine sulfide, dihexylphosphine oxide, trioctylphosphine oxide, trif Organic phosphorus compounds such as enylphosphine, organic silicone compounds such as hexamethyldisilazane and triphenyl silicone azide, organic cobalt compounds such as octacarbonyl dicobalt, organic chromium compounds such as hexacarbonylchromium and tricarbonyltolylchromium, triphenyl Examples include organic bismuth compounds such as bismuth, organic vanadium compounds, organic manganese compounds, and organic tungsten compounds. Also, N,N-dimethyl-N-cyclohexylamine oxide, N,N-dimethyl-N-
Phenylamine oxide, 1,4-dioxo-
1,4-diaza[2,2,2]bicyclooctane, phenazine-N-oxide, pyridine-N
-oxide, N-methylmorpholine-N-oxide, N-methylpiperidine-N-oxide, trimethylamine oxide, N-ethyl-
Examples include organic amine oxides such as N-methyl-N-butylamine oxide. Among the above catalysts, Lewis acids, boron trifluoride amine complexes, organic tin compounds, organic titanium compounds, organic zirconium compounds, and organic amine oxides are particularly effective. Although the amount of the catalyst used does not require strict limitations,
At least one of the above catalysts is used in an amount of 0.01 to 10% by weight, particularly preferably 0.1 to 5% by weight, based on the polyfunctional α-ketonitrile compound. In the present invention, a polyfunctional α-ketonitrile compound can be used as a thermosetting resin composition containing the catalyst. As mentioned above, the composition is an addition polymerization type solvent-free system, and may contain a solvent as desired, or may be mixed with various known additives, fillers, pigments, etc. It can also be done. Such compositions are easily cured by heating at 0-250°C for 1-200 hours. The resulting cured resin has excellent heat resistance and can be used for long periods of time even at temperatures as high as 250°C. The resin also has excellent electrical properties, chemical resistance, impact resistance, and self-extinguishing properties. Therefore, the thermosetting resin composition can be used as a material for a wide range of applications such as heat-resistant insulating varnishes, casting resins, mold resins for electronic components, impregnating and laminating resins, printed wiring resins, and interior resins. Useful. Next, the present invention will be described with reference to Examples. Synthesis example of polyfunctional α-ketonitrile compound 4,4′-[(1-methyl-1,1-ethanediyl)bis(4,1-phenyleneoxy)]bis[α,α′-dioxo-1,2-benzenediyl Synthesis of acetonitrile] []. In a 2-four-neck flask equipped with a stirrer, thermometer, and condenser, add 500 ml of dimethyl sulfoxide and 114.2 g of bisphenol A (2,2-bis(4-hydroxyphenyl)propane).
(0.500 mol) and stirred and mixed well. Then, 80.0 g of a 50% aqueous sodium hydroxide solution was added and mixed well with stirring to synthesize the sodium salt of bisphenol A. Next, add 300ml of toluene,
Water was removed azeotropically. To this, 239.2 g of 1,2-bis(methoxycarbonyl)-4-nitrobenzene
(1.00 mol) was added and kept at 70°C for 5 hours.
After cooling, the precipitate was separated. 150.0 g of 50% aqueous sodium hydroxide solution was added to the liquid, and the mixture was maintained at 50°C for 8 hours. After distilling off the solvent under reduced pressure, the residue was recrystallized from methanol to obtain colorless crystals [A] with a melting point of 225-230°C. The elemental analysis results of [A] were as follows. Analytical values: C66.7%, H4.3%, O29.0% Calculated values as C ₃₁ H ₂₄ O ₁₀ :
C66.9%, H4.3%, O28.8% In addition, the acid value of [A] was 398, which was 98.7% of the value calculated using the following structure. Next, add 150.0 g of [A] to a round-bottomed flask (No. 1) equipped with a condenser connected to a calcium chloride tube.
(0.270mol) and thionyl chloride 500.0g (4.20mol)
, warm to 80℃ and hold at that temperature for 5 hours. After distilling off excess thionyl chloride, the residue was thoroughly washed with dry toluene and n-hexane to obtain 165.8 g of colorless crystals [B]. In a four-neck flask equipped with a stirrer, thermometer, and reflux condenser, put 500 ml of dehydrated and purified N,N-dimethylacetamide, 165.8 g (0.263 mol) [B], and 94.3 g (1.05 mol) of copper cyanide. , and refluxed for 5 hours. After cooling, strain. N,N-dimethylacetamide was distilled off from the liquid under reduced pressure to obtain 154.3 g of a pale yellow liquid. The results of elemental analysis of the liquid were as follows. Analytical values: C70.7%, H3.4%, N9.6%, O16.3% Calculated values as C ₃₅ H ₂₀ N ₄ O ₆ :
C70.7%, H3.4%, N9.5%, O16.2% Also, when its infrared absorption spectrum was measured, absorption based on nitrile group was found at wave number 2225 cm ^-1 .
Absorption based on carbonyl groups was observed at 1680 cm ^-1 . From the above, the product has the following structure []
It is thought that it has. Examples 1 to 12 In each case, 1.0 g of the catalyst shown in Table 1 was added to 50.0 g of [) obtained in the above synthesis example, and the mixture was thoroughly stirred.
This mixture was heated at 180°C for 10 hours + 200°C for 5 hours to obtain a cured product. The wave number 2225cm ^-1 that existed before curing in the infrared absorption spectrum of all cured products
The absorption based on the nitrile group decreased, and a new absorption at 1500 cm ^-1 based on the cyanurate ring appeared. This revealed that the cured product was polycyanurate. The obtained cured product is a reddish brown resin, and the various properties of this cured product are as shown in Table 2.
It showed excellent heat resistance.

【table】

【table】

[Table] Example 13 25.0 g [] obtained in Example 1, 25.0 g of terephthaloyl cyanide, and 1.0 g of stannic chloride were added and mixed well. This mixture was heated to 180℃/10
A cured product was obtained by heating at +200°C for 5 hours. In the infrared absorption spectrum, the absorption based on the nitrile group at a wave number of 2225 cm ^-1 that existed before curing decreased, and a new absorption at 1500 cm ^-1 based on the cyanurate ring appeared. This revealed that the cured product was polycyanurate. The obtained cured product is a reddish-brown resin, and its properties are as shown in Table 3, and it has excellent heat resistance. Example 14 50.0 g of terephthaloyl cyanide and 1.0 g of stannic chloride were mixed and stirred well. This mixture was treated in the same manner as in Example 14 to obtain a reddish brown polycyanurate. The properties of the obtained polycyanurate are shown in Table 3, and it showed excellent heat resistance.

【table】

[Table] Measured values Characteristics after deterioration are values after 20 days of treatment at 250℃ As detailed above, according to the present invention, 200℃
It is clear that a heat-resistant cured product with excellent mechanical and electrical properties at high temperatures can be obtained by curing at such a relatively low temperature.

Claims (1)

[Scope of Claims] 1. A curable resin composition comprising a polyfunctional α-ketonitrile compound having at least two α-ketonitrile groups and 0.01 to 10% by weight of a cyanurate ring-forming catalyst. 2 Polyfunctional α-ketonitrile compound is 4,4′-
[(1-methyl-1,1-ethanediyl)bis(4,1-phenyleneoxy)]bis[α,α′-dioxo-1,2-benzenediacetonitrile] Curable resin composition according to item 1.