JPS6056169B2 - thermosetting resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermosetting resin composition, and its purpose is to produce electrically insulating materials and laminates that have excellent heat resistance, mechanical strength, and workability. resin materials for
The object of the present invention is to provide a thermosetting resin composition that is extremely useful for coating materials, molding materials, and the like.

Conventionally, polyester resins, phenol resins, epoxy resins, and the like are well known as thermosetting resins used for electrical insulation materials, structural materials, and the like.

However, these generally do not have sufficient heat resistance, and their fields of use are naturally limited. However, recently,
In response to higher performance, more compact size, and harsher operating conditions in electrical equipment, chemical equipment, etc., resin materials are required to have excellent heat resistance.
Typical examples of such heat-resistant resin materials include polyimide resins, silicone resins, diphenyl ether resins, and resins obtained from polyfunctional isocyanates and polyfunctional epoxy compounds.

However, polyimide resin requires a special solvent and
Curability was extremely poor, and there were problems with workability and processability.
Silicone resins have a disadvantage in that they cannot be used as structural materials because of their extremely low mechanical strength. Diphenyl ether resin is soluble in common general-purpose solvents and has high strength at high temperatures. However, this diphenyl ether resin also has extremely poor curability, requiring a great deal of time and energy for molding and after-curing, which poses a major practical problem. Polyfunctional isocyanate epoxy compound-based resins do not have the above drawbacks, but because they use isocyanate compounds, there are serious problems with toxicity and deterioration due to moisture, making it difficult to work during actual work. Process control is a difficult problem.From this point of view, the present inventors have developed electrical insulating materials, structural materials, and paints that have excellent heat resistance and mechanical strength, as well as excellent workability and processability. As a result of various research aimed at developing materials, we have developed a prepolymer obtained by reacting a polyfunctional cyanate ester compound and a bismaleimide compound, and an isocyanate-modified epoxy obtained by reacting an isocyanate compound with an epoxy compound. The present invention was completed based on the new discovery that a resin composition characterized by blending a curing catalyst with a resin provides a thermosetting resin composition that can easily achieve the above objectives. I came to the conclusion.

To explain the present invention in detail below, the thermosetting resin composition of the present invention has a cyanate group and a maleimide group at the terminal obtained by reacting a polyfunctional cyanate ester compound and a bismaleimide compound, and has the following: The estimated structure (Ar,
, Ar'' is an aromatic residue) and is obtained by reacting 1.5 to 5 equivalents of an epoxy compound with 1 equivalent of an isocyanate compound under a heterocycle-forming catalyst. Isocyanate-modified epoxy resin 70 containing an oxazolidone ring and an isocyanuric ring
It is made by blending a curing agent to ~30% by weight.

In the present invention, the prepolymer of a polyfunctional cyanate ester compound and a bismaleimide compound, which is one component, is prepared in an appropriate solvent such as methyl ethyl ketone or dimethyl formamide, and preferably, per equivalent of the polyfunctional cyanate ester compound. ．． For example, 0.5 to 2 equivalents of a bismaleimide compound is heated at a temperature of about 50 to 150°C for 5 minutes to 2
For about an hour, organic bases such as tertiary amine imidazoles, organic metal salts such as zinc octylate, tin oleate, and cobalt naphthenate, and 5-Lewis acids such as tin tetrachloride and zinc chloride are added in the presence or absence of a catalyst. It can be obtained by reacting in the presence of

In this case, the reason why the ratio of the -bismaleimide compound is set to 0.5 to 2 equivalents per equivalent of the polyfunctional cyanate ester compound is that below this range, the heat resistance, moisture resistance, etc. of the cured product will be poor. This is because if the amount exceeds this range, the curability of the resin composition tends to decrease and the strength of the cured product tends to decrease. In addition, it is also possible to make these components constituting the prepolymer exist in the resin composition in a free form. The polyfunctional cyanate ester compound has the following general formula (where n is 2 or more, usually 5 An aromatic cyanate ester represented by the following positive number (where R is an aromatic organic group), or this cyanate ester, can be mixed with mineral acids, Lewis acids, sodium hydroxide, sodium alcoholates, tertiary amines, etc. A prepolymer obtained by polymerization in the presence of a catalyst such as a base such as, a salt such as sodium carbonate or lithium chloride, or a phosphoric acid ester such as tributylphosphine can be used.

For example, cyanic acid esters from bisphenol A and cyanide halides, prepolymers thereof, etc. are commercially available and may be used satisfactorily for the purposes of the present invention. As the bismaleimide compound, N,N-ethylene bismaleimide, N,N''-hexamethylene bismaleimide,
N,N′-p-phenylene bismaleimide, N,N″-
(methylene di p-phenylene) bismaleimide, N,
Examples include N''-(oxydi p-phenylene) bismaleimide.

Note that the prepolymer obtained from a cyanate ester compound derived from bisphenol A and N,N''-(methylene-p-phenylene) bismaleimide is commercially available as a resin (Mitsubishi Gas Chemical KK), and is available in various grades. are available and can be fully used for the purpose of the present invention.

Further, the isocyanate-modified epoxy resin which is a component of the present invention can generally be produced as follows. For example, 1 to 5 equivalents of an epoxy compound are charged to 1 equivalent of an isocyanate compound, and basic compounds such as quaternary ammonium salts and tertiary amines, known heterogeneous compounds such as lithium promidophosphine oxyadduct, and zinc bromide are added. 1 at 100-200°C in the presence of a ring-forming catalyst.
By reacting for ~1 m, an epoxy resin containing an oxazolidone ring and an isocyanate ring and having an epoxy group at the end is obtained. The reason for setting the ratio of isocyanate compound to 1 equivalent of isocyanate compound in this case is 1 to 5 equivalents because if it is less than that, there is a risk of gelation during synthesis of the isocyanate-modified epoxy resin, and if it exceeds this range, the cured product will be This is because there is a tendency for heat resistance to decrease. The isocyanate compound used in the present invention is
In view of the spirit of the present invention, divalent isocyanate compounds are desirable, such as tolylene diisocyanate (2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
-tolylene diisocyanate), 4,4-diphenylmethane diisocyanate, 4,4-diphenyl ether diisocyanate, hexamethylene diisocyanate, 1,5-naphthylene diisocyanate, and the like. Further, as the epoxy compound used in the present invention, in view of the purpose of the present invention, an epoxy compound having two or more epoxy groups in one molecule is desirable. Bisphenol-type commercial epoxy resins such as DER332 (Dow Chemical Company, epoxy equivalent weight 174), DEN43L (Dow Chemical Company, epoxy equivalent weight 174),
75), novolac type commercially available epoxy resins such as DEN438 (Dow Chemical Company, epoxy equivalent weight 179), E
Cresol novolac type epoxy resin such as CNl273 (Ciba, epoxy equivalent weight 225), CY-183
Examples include commercially available glycidyl ester type epoxy resins such as (Ciba Co., Ltd., epoxy equivalent: 154).

Next, as a curing catalyst, benzyldimethylamine, 2
- Tertiary amines such as methylbenzyldimethylamine,
2-ethyl-4-methylimidazoles, them and BF
3. Imidazole salts with phosphoric acid, isocyanuric acid, etc., organic metal salts such as zinc octylate, tin octylate,
Acetylacetonates such as cobalt, chromium, and manganese are effective.

In the present invention, the blending ratio of the prepolymer obtained by reacting the cyanate ester compound and bismaleimide with the isocyanate-modified epoxy resin is within the range of 30 to 70 for the former and 70 to 30 for the latter. It is desirable to provide the cured product with excellent heat resistance and mechanical strength.

That is, the amount of isocyanate-modified epoxy resin is 3%.
Cured products of the following compositions generally tend to become brittle and susceptible to mechanical shock, etc., and at m weight % or more,
Heat resistance etc. tend to decrease. The amount of the curing catalyst to be used is determined depending on the purpose of use, but it is generally desirable to mix the curing catalyst in an amount of about 0.2 to 2% by weight based on the total amount of the resin in terms of workability and properties of the cured product. The resin composition of the present invention can be obtained by blending the above-mentioned components in the form of a solid powder, in a molten state or in a solution state using a solvent.

Curing conditions vary depending on the composition and usage conditions, but in general, curing conditions at 130 to 230°C for about 1 hour to about 1 hour are appropriate. Therefore, the resin composition of the present invention can be used in the form of a varnish dissolved in a suitable organic solvent, or can be used in the form of a powder. For example, when using the varnish as a varnish, the varnish is coated or impregnated onto a laminate base material such as glass cloth, and then the prepreg obtained by drying and removing the solution is layered, and this is then pressure-heat molded. By applying this method, a laminate product with excellent heat resistance and mechanical properties can be obtained. In addition, known fillers, silica powder,
Glass powder, calcium carbonate powder, glass fiber, carbon fiber, carbon black, etc., or a powder composition containing pigments, flame retardants, lubricants, etc. is filled into a pre-prepared mold and heated and pressurized to make it heat resistant. It is also possible to obtain resin molded products with excellent properties. The above powder composition can also be used as a powder coating resin. Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 760y of bisphenol type epoxy resin Epicoat 828 (Shell Chemical, epoxy equivalent 190) and 250q of 4,4-diphenylmethane diisocyanate were mixed and reacted at 150°C for 3 hours using 0.6y of tetraethylammonium bromide as a catalyst. .

The product was a solid resin at room temperature and had an epoxy equivalent weight of 343. By analyzing the infrared absorption spectrum, 2250c
The absorption based on the isocyanate group near m-1 disappears, and the absorption based on the oxazolidone ring and isocyanurate ring near 1750,1705cff1-1, 915,83
By showing the absorption of epoxy groups around 0 cm-1, it was confirmed that an isocyanate-modified epoxy resin containing an oxazolidone ring and an isocyanurate ring was produced. By dissolving this resin in dioxane, a solution having a solid content of 50% was prepared. Next, 2,2-bis(4″-cyanatophenyl)propane 5579, which is a cyanate ester compound of bisphenol A, and N,N″-(oxydi-p-phenylene)bismaleimide 721y were mixed with N,N″-dimethylformamide. 1278y and heated to 80°C to dissolve uniformly, 2-ethyl-4
-0.5y of methylimidazole was added, and the mixture was heated and stirred for 2 hours.

The thus obtained prepolymer solution with increased viscosity 1800
1200y of the dioxane 50% solution of the isocyanate-modified epoxy resin obtained above was mixed with g, and CO (■)
Acetylacetonate 7f was added and thoroughly stirred and dissolved to obtain a uniform resin solution.

The resin solution thus obtained was applied to an aminosilane-treated glass cloth and dried at 140°C to form a powder. Repreg was manufactured. After that, several sheets of this prepreg were stacked together and preformed while degassing twice with a press heated to 170℃, and then 80k9/C! A laminate was obtained by heating and press-molding the three powders at a pressure of i. Furthermore, the laminate was post-cured at 200°C, 1CJII! A heat treatment was performed between the two. The bending strength of this laminate at 25°C was 53.1k9/Rd, and the bending strength at 200°C was 47.6kg/Td. Also, 240℃, 5
The bending strength after heating for 0m is 51.2k9 at 25℃
/w! It was i. Example 2 Cresol novolac type epoxy resin ECN-1280
(Ciba, epoxy equivalent 230) 1150f and 4,4″
-diphenylmethane isocyanate 125y (0.5 mol) and tetraethylammonium bromide 0.6f were mixed and reacted at 180°C for 2 hours.

The product is a solid resin at room temperature and has an epoxy equivalent of 289.
It was hot. Further, as in Example 1, the formation of an isocyanate-modified epoxy resin containing an oxazolidone ring and an isocyanuric ring was confirmed by an infrared absorption spectrum. Next, a 70% solution of 2,2-bis(4″-cyanatophenyl)propane trimer (including some monomers) in methyl ethyl ketone (Mitsubishi Gas Chemical, trade name revision-20)
60) 397.5y<5N, N-(methylene di p-phenylene) bismaleimide 717y was charged into N,N-dimethylformamide 876y, heated to 80°C,
After uniformly dissolving, 1 f of zinc octylate was added, and the mixture was heated and stirred for about 1 hour to obtain a prepolymer solution with increased viscosity.

To 1000 y of the thus obtained prepolymer solution, 50% dioxane of the isocyanate-modified epoxy resin obtained above was added.
1000 y of the solution was mixed, 10 y of zinc octylate was added, and the mixture was thoroughly stirred and dissolved to obtain a uniform resin solution. Using this resin solution, a laminate was produced under the same conditions as in Example 1. The bending strength of this laminate at 25°C is 50.
2k9/i, and the bending strength at 200°C is 41.
It was 5k9/RlTlt. The bending strength after heating at 240° C. for 50 minutes was 50.7 k9/i.
Example 3 Bisphenol type epoxy resin DER332 (Dow Chemical Company, epoxy equivalent weight 174) 1044y and tolylene diisocyanate (2,4-di 80%, 2,6-di 20%)
) 348y (2 mol) and tetramethylammonium iodide 1.4y in dimethylformamide 1393V and reacted at 160°C for 5 hours to prepare a 50% dimethylformamide solution of an isocyanate-modified epoxy resin containing an oxazolidone ring and isocyanuric acid. Obtained.

600 g of the isocyanate-modified epoxy resin solution obtained in this way, 2,2-bis(4-cyanatophenyl)propane and N,N-(methylene di-1p-phenylene)
1400 g of a 50% N,N-dimethylformamide solution of prepolymer BT-2600 (manufactured by Mitsubishi Gas Chemical) made from bismaleimide was mixed, and Cr(m) acetylaceto-
Nato 10y was added and thoroughly stirred and dissolved to obtain a uniform resin solution.

Using this resin solution, a laminate was obtained under the same conditions as in Example 1. The bending strength of this laminate at 25°C is 54
．． 1k9/T! Uft, and the bending strength at 200°C was 51.3k9/i. Also, 240℃, 5
001] The bending strength after heating for V is 51.2k9/i
It was hot. Example 4 Novolac type epoxy resin DEN-
438 (Dow Chemical Company, epoxy equivalent weight 179) 107
4y and tolylene diisocyanate (2,4-di 80%)
, 2,6-20%) 174y (1 mol),
By reacting at 160°C for 3 hours using 0.6y of tetraethylammonium bromide as a catalyst, an isocyanate-modified epoxy resin containing an oxazolidone ring and an isocyanuric ring and having an epoxy equivalent of 258 was obtained which was solid at room temperature.

This isocyanate-modified epoxy resin 500y and BT-
A mixture of 2600 prepolymer (described above) 500y, BF3/monoethylamine 10y1, silica powder 500y1, and Montanic acid wax 20y was melt-mixed in a kneader under heating, and after cooling, it was crushed to obtain a molded powder.

This powder was heated to 100k9/Cfl using a mold at 180°C.
After the I-powder pressure molding was carried out at a pressure of 200° C., post-curing was performed at 200° C. for 5 hours. 25°C of the molded product thus obtained.
The bending strength at room temperature is 14.2k9/d,
It was 5.4 kg/i at 180°C. Also, 243℃,
The bending strength at room temperature after heating deterioration for 50 (g) is 13
．． It was 7k9/Wrlt. Example 5 Bisphenol type epoxy resin DER332 (described above) 6
By mixing 96y and 250y (1 mol) of 4,4-diphenylmethane diisocyanate and reacting at 160°C for 3 hours with 0.6y of tetraethylammonium bromide as a catalyst, an oxazolidone ring having an epoxy equivalent of 321 and a solid at room temperature was obtained. , an epoxy resin containing an isocyanuric ring was obtained.

This isocyanate-modified epoxy resin 100y, 2,
Using 2-bis(4-cyanatophenyl)propane trimer BT26OO (described above) 795y and N,N-(methylene di-p-phenylene) bismaleimide 358y,
Isocyanate ester-bismaleimide polymer 4 obtained by producing in the same manner as in Example 1 and then removing the solvent under vacuum heating
30y. ．． BF3.2-Methylimidazole 14y1 Titanium oxide powder 700y1 Modaflow 10da (Monsanto Co., Ltd., leveling agent) were melt-mixed under heating in a kneader, cooled and pulverized, and sieved into black mesh.

A galvanized steel plate with a thickness of 3 Twt, preheated to 200°C, was immersed in the suspended powder of this powder composition for about 158 minutes, then heated at 180°C, and fluidized to an average coating thickness of 200 microns. A cured resin coating film was obtained by the method. DuPont impact test (load 500y1 center of impact 114
The test result was 260 (inch), and the Eriksen test was 6T! It was Rm.

Claims (1)

[Claims] 1(a) Prepolymers 30 to 7 obtained by reacting a polyfunctional cyanate ester compound and a bismaleimide compound
0% by weight, (b) 70 to 30% by weight of an isocyanate-modified epoxy resin obtained by reacting 1.5 to 5 equivalents of an epoxy compound with 1 equivalent of the isocyanate compound under a heterocycle-forming catalyst, and (c) A thermosetting resin composition comprising a curing catalyst.