JPS6056170B2 - Heat resistant resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-resistant resin composition, and more particularly to an isocyanate-modified epoxy resin composition. The present invention relates to a heat-resistant resin composition containing a resin, an acid anhydride as an epoxy curing agent, and a maleimide compound, which has excellent thermal stability and excellent mechanical and electrical properties.

The resin composition of the present invention is particularly useful as an electrically insulating material, and can be used in a wide range of applications, such as impregnating varnishes, casting resins, and laminating resins.

The method of curing epoxy resins with acid anhydrides is common and is applied in a wide range of fields.

Although it does show excellent properties under normal conditions, it cannot withstand high temperature and long-term use because of the large decrease in strength and large deterioration of heat resistance at high temperatures. We have carried out extensive research to improve this point and have arrived at the present invention. The present invention provides a composition (4) obtained by blending an isocyanate-modified epoxy resin obtained by reacting a polyfunctional epoxy resin and a polyfunctional isocyanate compound under conditions with an excess of epoxy terminals and an acid anhydride as an epoxy resin curing agent. and a polyfunctional maleimide compound (B) to provide a resin composition with extremely excellent heat resistance.

In the present invention, the isocyanate-modified epoxy resin obtained by the reaction of a polyfunctional epoxy resin and a polyfunctional isocyanate compound forms an oxazolidone ring by the reaction between the epoxy ring and the isocyanate group, and becomes an oxazolidone ring-containing epoxy resin. Taking advantage of the fact that the compound has a high heat distortion temperature, excellent mechanical properties, and strong properties, and by adding a polyfunctional maleimide compound to this compound, the stability against thermal deterioration of the maleimide polymer is combined with this. This provides a well-balanced resin composition with excellent thermal stability, mechanical properties, and electrical properties.

In this heat-resistant resin composition, the epoxy component and the maleimide component form separate crosslinked networks and are entangled with each other with good compatibility, forming an interpenetrating network structure.
) is thought to strengthen the characteristics of each component.

Examples of the polyfunctional epoxy resin that can be used in the present invention include bisphenol A diglycidyl ether type Epicote 826, 827, 828 (Shell Chemical F1), GY-252, GY-260 (Ciba Geigy Corporation), Novolac type DEN43l, 4 such as DER33Ol33l, 332 (Dow Chemical Co., Ltd.)
38 (Dow Chemical Co., Ltd.), ECN1273 (Ciba Geigy Co., Ltd.), and an alicyclic type CY-179 (Ciba Geigy Co., Ltd.).

In addition, as a polyfunctional isocyanate compound, general formula (
0=C=N)x-R4(N=C=0)y (R is a divalent organic group, x+y is an integer from 2 to 5), such as tolylene diisocyanate, xylylene diisocyanate, 4 , 4''-diisocyanate diphenylmethane, isophorone diisocyanate, etc.

Further, as the acid anhydride as an epoxy curing agent that can be used in the present invention, acid anhydrides represented by the general formula, such as phthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, Examples include methyltetrahydrophthalic acid, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, butanetetracarboxylic anhydride, and the like.

Polyfunctional maleimide compounds that can be used in the present invention are represented by general formulas (1), (■), and (■) (wherein R3 is the same as above, m is from 0.5 to 10 on average). As shown by the general formula (1),
For example, N,N''-(methylene di-P-phenylene) dimaleimide, N,N''-(oxydi-P-phenylene) dimaleimide, N,N''-m-phenylene dimaleimide,
N,N″-P-phenylene dimaleimide, N,N″-2
,4-tolylene dimaleimide, N,N''-2,6-tolylene dimaleimide, N,N'-m-xylylene dimaleimide, N,N''-P-xylylene dimaleimide, N,N''
- Hexamethylene dimaleimide, etc., with general formula (■)
Examples of the compound represented by the formula include polyphenylmethylene polymaleimide, which can be suitably used alone or in combination of two or more.

In the present invention, a range of 2 to 50 equivalents of the epoxy group of the polyfunctional epoxy resin is blended to 1 equivalent of the isocyanate group of the polyfunctional isocyanate compound shown above.
The reaction is carried out at 00° C., preferably from 80° C. to 180° C., for 0.5 to 5 hours without a catalyst or in the presence of a catalyst consisting of a tertiary amine, a quaternary ammonium salt, or various metal salts to obtain an isocyanate-modified epoxy resin.

An acid anhydride is blended into the obtained isocyanate-modified epoxy resin at a normal epoxy curing ratio to form a composition. The desired composition is prepared by adding 5 to 8 parts by weight of the polyfunctional maleimide compound (B) to 20 to 95 parts by weight of composition (4). If the ratio of the polyfunctional epoxy resin to 1 equivalent of the polyfunctional isocyanate compound is less than 2 equivalents, the softening point will be high and the workability will be poor, making it unsuitable for practical use. If the ratio is less than 50 equivalents, the mechanical strength due to isocyanate modification will decrease. The effect of increasing heat deformation temperature and heat deformation temperature cannot be obtained. If the ratio of the polyfunctional maleimide compound (B) to the composition (4) is 5 parts by weight or less, no improvement in thermal stability can be obtained by adding the polyfunctional maleimide compound, and if the ratio is 8 parts or more, the thermal stability is insufficient. However, the crosslinking density becomes too high, resulting in low mechanical strength.

In addition, in the present invention, phenoxy resins represented by the general formula, such as U. C. C. (KK)
PK8, etc. can be used in conjunction with the above, if necessary.

In this case, the maleimide and the epoxy cured network are intertwined as a flexible component, resulting in the effect of improving the flexibility and rack resistance of the cured product. can be done. Phenoxy resin is usually commercially available with a molecular weight of 1000.
0 to 60,000 is preferably used. The amount of phenoxy resin blended is suitably within a range of no more than 2 parts per 10Ciff1) of the above resin composition. The lower limit of the amount to be used should be determined depending on the purpose of use, but if it is less than 0.5 parts, the properties unique to phenoxy resins will not be sufficiently expressed.

On the other hand, if the amount of phenoxy resin blended exceeds the additive amount, the viscosity will increase too much and the work will become difficult. In this way, the resin composition is not only solvent-free and has excellent thermal stability, but also has particularly good mechanical properties and provides a cured resin with low electrical insulation properties, such as varnish for electromechanical impregnation, It can be used for a wide range of purposes including casting resins and laminating resins. In addition, fillers, colorants, and other various additives may be added as necessary. Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Bisphenol A diglycidyl ether-based DER332 (Dow Chemical Company) 350y (Dow Chemical Company) with an epoxy equivalent of 175
2 equivalents) was reacted with 4,4''-diisocyanate phenylmethane 125y (1 equivalent) using a tetraethylammonium chloride catalyst at 150°C for 2 hours.

The epoxy equivalent showed 460. According to the infrared absorption spectrum, 1410cff1-1, 1750C! Absorption generation based on oxazolidone ring formation was observed in FL-1, and 2
Since the absorption of -NCO from 200 to 23(1)d-4 disappeared, it was confirmed that the desired isocyanate-modified epoxy resin was produced. To this isocyanate-modified epoxy resin 460$F (1 equivalent), 300y of polyphenylmethylene polymerimide having a composition represented by R4=H in the general formula (■), and 149$F (0.9 equivalent) of methyltetrahydrophthalic anhydride were added. was added to prepare a composition.

This material was cured at 150°C for 8 hours and then at 200°C to produce a cured piece. This material exhibited a heat distortion temperature of 170° C. or higher (TMA method).

The bending strength at 25°C is 15.0k9/I. ．． l5O℃
It shows 12.5k9/i and maintains high strength even at high temperatures. Weight loss after 25 hours at 240'C is 1.8%
The bending strength is 14.0k9/i, showing almost no decrease in strength even after long-term deterioration at high temperatures.

In addition, the adhesive strength by Straka method is 18.0k at 250℃.
9. Maintains high adhesive strength of 16.0 kg at 180°C up to high temperatures. In addition, a casting resin composition containing 20 parts of Fuse Rex RD-8 (Tatsumori Co., Ltd.), which is a fused silica as a filler, to 10 parts of the above-mentioned resin was tested in the Orient Washer Rack Test. It exhibited a crack index of 4 or higher, indicating good flexibility.

Example 2 To the above epoxy resin DFR33235Oy (2 equivalents), 22.2y of isophorone diisocyanate (
0.2 equivalent) was added thereto, and the mixture was reacted with a triethylamine catalyst at 130° C. for 2 hours.

The epoxy equivalent showed 210. The infrared absorption spectrum shows the generation of absorption based on oxazolidone ring formation at 1420c'1 and 1750c71-1, and at 2250c'
Since the absorption of -NCO in Example 1 disappeared, it was confirmed that the desired isocyanate-modified epoxy resin was produced. This isocyanate-modified epoxy resin was made into a composition by adding 210f (1 equivalent), N,N-(tatilene di-P-phenylene) dimaleimide 500y1, and methylhexahydrophthalic anhydride 157y (0.9 equivalent).

After 150 hours of C-free heating, this product was cured by heating at 200° C. for 8 hours to produce a cured piece.

This material exhibited a heat distortion temperature of 170°C or higher.

(TMA method). In addition, the bending strength is 17.0k9 at 25℃
/Tdll5O°C showed 15.0k9/i, and maintained high strength even at high temperatures.

The weight loss after 25 cycles at 240°C was 1.5%, and the bending strength was 1.6k9/i, showing almost no decrease in strength even after long-term deterioration at high temperatures.

Adhesive strength by Straka method is 17.0 kg at 25°C, 1
It maintained high adhesive strength even at high temperatures, weighing 16.5 kg at 80C.

In addition, in terms of electrical properties, the Tan δ -temperature properties showed stable values of 0.20% in normal conditions and 1.20% at 200° C., indicating good properties.

Example 3 DER332175y (1 equivalent), 1 Volatile type epoxy resin ECN1273 (Ciba Geigy Corporation) 1
12.5 V (1 equivalent) was added, and 43.5 f (0.5 equivalent) of tolylene diisocyanate was reacted with zinc octylate as a catalyst at 150° C. for 2 hours.

The epoxy equivalent showed 220. Infrared absorption spectra revealed oxazolidone ring formation, -NC, as in Example 1.
The disappearance of O was observed, and the production of an isocyanate-modified epoxy resin was confirmed.

To 220f (1 equivalent) of this isocyanate-modified epoxy resin, 50g of polymaleimide represented by R4=H in the general formula (■), 160y of methylnadic anhydride (0.
9 equivalents) was added to prepare a composition.

A sample was obtained by curing under the same conditions as in Example 1. Bending strength is 15.0kg at 25℃/12.0k9 at Ill5O℃
/i, and maintained high strength even at high temperatures. 240℃2
Weight loss after 5CR is 2.2% and bending strength is 13.0
It exhibited excellent stability even under high temperature and long-term deterioration at k9/i.

It showed good values for both adhesive strength and electrical properties.

Example 4 For DER332350y (2 equivalents), 4,
4″-diisocyanate diphenylmethane 12.5y (
stomach). 10 equivalents), isophorone diisocyanate 1.1
'(4). 1 equivalent) was added thereto, and the mixture was reacted at 150° C. for 1 hour using a tetraethylammonium chloride catalyst.

The epoxy equivalent showed 210. Formation of an isocyanate-modified epoxy resin was confirmed by infrared absorption spectrum in the same manner as in Example 1.

210y (1 equivalent) of this isocyanate-modified epoxy resin! This is polyphenylmethylene polymerimide 100V having a composition represented by R4=H in the general formula (■)
1 Furthermore, methyltetrahydrophthalic anhydride 149f (
0.9 equivalent) was added to prepare a composition.

This material was cured at 150°C for an hour and then at 180°C to produce a cured piece. This material exhibited a heat distortion temperature of 170° C. or higher (TMA method).

Furthermore, the bending strength was 15.5k9 at 25°C/13.0kg/Tlrlt at Ill5O°C, and it maintains high strength even at high temperatures.

The weight loss after 240'Cl25 heating was 2.0%, and the bending strength at that time was 14.2k9/i at 250°C, showing almost no decrease in strength even after long-term deterioration at high temperatures.

In addition, the adhesive strength by Straka method is 17.5k9 at 25℃.
, maintains high adhesive strength of 16.0k9 at 180°C up to high temperatures. Furthermore, in terms of electrical properties, the volume resistivity is 1 at 25°C.
It showed good values of 016 Ω-d or more and 1011 Ω-0 or more at 150°C. Fused silica fuse RD-8 (Tatsumori Co., Ltd.) as a filler was added to 10 parts of the above resin.
) The casting resin containing 200 parts by weight showed a crack index of 4 or more in the orifice washing machine crack test and exhibited good flexibility.

Claims (1)

[Scope of Claims] 1. Blends (A) of isocyanate-modified epoxy resin obtained by reacting a polyfunctional epoxy resin and a polyfunctional isocyanate compound with an excess of epoxy terminals and an acid anhydride as an epoxy resin curing agent (A) 20- A heat-resistant resin composition containing 95 parts by weight and 5 to 80 parts by weight of a polyfunctional maleimide compound (B). 2. The heat-resistant epoxy resin according to claim 1, characterized in that at least one type of epoxy resin selected from bisphenol A digrine diether type, novolac type, and alicyclic type epoxy resin is used as the polyfunctional epoxy resin. resin composition. 3 As a polyfunctional isocyanate compound, the general formula (O=
C=N)x-R_4-(N=C=O)y (in the formula, R_4
is a divalent organic group, x+y is an integer from 2 to 5)
The heat-resistant resin composition according to claim 1 or 2, characterized in that the compound represented by the following is used. 4 Polyfunctional maleimide compounds have general formulas▲Mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(I)
(In the formula, R_3 represents hydrogen or a methyl group, R_4 represents a divalent organic group), ▲Mathematical formulas, chemical formulas, tables, etc.▼
...(II) (In the formula, R_3 is hydrogen or a methyl group, n indicates a number from 0.5 to 5 on average), ▲Mathematical formulas, chemical formulas, tables, etc.▼... (III) (In the formula, R_3 is hydrogen or a methyl group, m is 0.
The heat-resistant resin composition according to any one of claims 1 to 3, characterized in that it is a compound represented by any one of the following (indicating a number from 5 to 10). 5 20 to 95 parts by weight of a blend (A) of an isocyanate-modified epoxy resin obtained by reacting a polyfunctional epoxy resin and a polyfunctional isocyanate compound with an excess of epoxy terminals and an acid anhydride as an epoxy resin curing agent; Composition 1 consisting of 5 to 80 parts by weight of functional maleimide compound (B)
00 parts by weight, phenoxy resin (C) more than 02
A heat-resistant resin composition containing 0 parts by weight or less.