CA1118941A - Heat resistant resin composition - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A heat resistant resin composition comprises 100 wt.
parts of a mixture (I) and 0 to 10 wt. parts of a phenoxy resin [II] wherein the mixture [I] comprises 80 to 5 wt. parts of (a) a mixture of 0 to 95 wt. parts of the first maleimide compound obtained by reacting an aromatic amine with maleic anhydride and/
or a maleic anhydride derivative and 100 to 5 wt. parts of the second maleimide obtained by reacting an aromatic amine with a cyclic acid anhydride not having an unsaturated double bond and maleic anhydride and/or a maleic anhydride derivative and 20 to 95 wt. parts of (b) an epoxy resin.

Description

The present invention relates to a heat resistant resin composition.
In general, a non-solvent type varnish does not contain a solvent, thus all of the components can be effectively used without loss and no volatile matter is vaporized thus desirable from hygienic safetyconsiderations. Accordingly, non-solvent type varnishes have been mainly used instead of conventional solvent type varnishes.
Unsaturated polyester resins and epoxy-modified resins have been used in the non-solvent type varnishes. These resins readily deteriorate at high temperature. The resins are thus dis-advantageously not durable over a long time. For example, epoxy compounds have been used, hardening being effected with a hardener, such as amino compounds and acid anhydrides, as resins having suitable electrical characteristics, dimensional stability and chemical resistance in various fields. However, the heat resistance of the epoxy resin is not satisfactory~
It is known that maleimide compounds may be polymerized to produce resins having high heat resistance. For example, the product of three dimensional polyimides by polymerizing solely N, N'-di-substituted maleimide with heating is disclosed in French Patent No. 1,455,514. However, the three dimensional polyimides have high cross-linkages whereby cracks are Eormed readily on heating and cooling. Accordingly, these polyimides are dis-advantageously un-suitable as casting resins;
It has been proposed in Japanese Patent Publication No.
12600/1974, to obtain resins having high heat resistance by combining the epoxy resin with maleimide compound. The resin obtained by the combination of the epoxy resin and the maleimide compound has high heat resistance. However, the varnishes contain-ing the resin have the disadvantage of precipitate the resin on storage over a long time because of the low solubilityof the maleimide compound. Moreover, the heat shrinkage of the resin in the hardening step is high and adhesion on the surface of a coil is not suitable in an immersing step or a casting step for a large coil the resins peeling off or cracking causing problems in practical use.
The present invention provides a resin composition having excellent heat resistant and mechanical characteristics and does not have the aforesaid disadvantageous characteristics.
According to the present invention there is provided a heat resistant resin composition which comprises 100 wt. parts of a mixture [I] and 0 to 10 wt. parts of a phenoxy resin [II]
wherein the mixture [I] comprises 80 to 5 wt. partsofa(a) a mixture of 0 to 95 w-t. parts of a first maleimide compound obtained by reacting an aromatic amine with at least one of maleic anhydride and a maleic anhydride derivative and 100 to 5 wt. parts of a second maleimide obtained by reacting an aromatic amine with a cyclic acid anhydride not having a unsaturated double bond and at least one of maleic anhydride and a maleic anhydride derivative and 20 to 95 wt. parts of (b) an epoxy compound.
The second maleimide compounds used in the resin of the present invention should be mixed imides which have a low melting point caused by a eutectic effect, are easily soluble and have high thermal stability. The degree of unsaturation in one molecule can be controlled by selecting the molar ratio o~ the cyclic acid anhydride having an unsaturated double bond to the cyclic acid anhydride having no unsaturated double bond. Accord-ingly, the resin compositions of the present invention are stahle without any precipitate formation. Even though the imide content is increased to give higher heat resistance, a baked resin having low shrinkage and excellent mechanical properties can be obtained by decreasing the ratio of the imide having an unsaturated bond. ;

3g4~
When a phenoxy resin having a large molecular weight is incorporated in the resin composition of the present invention, the phenoxy resin component having a large molecular weight and high flexiblity is dispersed in both the baked network of the maleimide compound and the baked net~ork of the epoxy compound whereby the shrinkage during baking is decreased, flexibility is imparted to the baked resin and its adhesiveness is improved because of free hydroxy group of the phenoxy resin.
The resin compositions of the present invention have excellent adhessiveness, impregnating properties and casting properties. They also, have low shrinkage and yield baked products having excellent flexibility and heat resistance.
Accordingly, the resin compositions can be used in various fields such as non-solvent type varnishes for impregnating coils, resins for casting and resins for laminating, especially impregnation type varnishes for insulation of rotary electric machines.
The first maleimides used in the present invention include N-substituted compounds having the formula ~0 ~
HC - C

ll N - R2 c cf -`
Rl O
wherein Rl represents hydrogen atom or an alkyl group, R2 represents a monovalent organic group, such as an alkyl, an aryl and an aralkyl group and a halogen substituted group thereof.
Suitable maleimides include N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octylmaleimide, N-dodecylmaleimide, N-phenylmaleimide, N-p-tolylmaleimide, N-m-tolylmaleimide, N-~-naphthylmaleimide, N-benzylmaleimide or a mixture thereof.

The first maleimides also include N,N'-disubstituted ( ~18~
maleimides having the formula HC - C~
I \ ~ C - CH
l N - R3 - N~ ll /C C~ ~,C--C\
Rl Q Rl wherein Rl represents hydrogen atom or an alkyl group and R3 represents a divalent organic group such as an alkylene, an allyl-ene or an aralkylene group. Suitable maleimides lnclude N,N'-(methylene-di-p-phenylene) dimaleimide, N,N'-(oxy-di-p-phenylene) dimaleimide, N,N'-m-phenylene-dimaleimide, N,N'-p-phenylenedi-maleimide, N,N'-2,4-tolylenedimaleimide, N,N'-2,6-tolylenedi~
maleimide, N,N'-m-xylenedimaleimide, N,N'-p-xylenedimaleimide, N,N'-oxydipropylenedimaleimide, ethylenedioxybis-N-propylmaleimide, oxybis-N-ethylmaleimide, N,N'-ethylenedimaleimide, N,N'-tri-methylenedimaleimide, N,N'-tetramethylenedimaleimide,N,N'-hexa-methylenedimaleimide, N,N'-dodecamethylenedimaleimide and mixtures thereof.

The first maleimides also include poly ~maleimides having the formula o C~ CH

¦ H2~ //--C,R
n ~vherein :Rl represents hydrogen atom or an alkyl group and n represents 0. 5 to 5 as an average.
The aromatic amines used for forming the second maleimides used in the present invention include (H2N)~(NH2~o (I) :~

~ ~ 4 4~L

(H2N) ~ (NH2)~ (II) (H2N),~NH~ )I~ (111) (H2N~ (NH2)Q ~IV)

2 ~ CH2 ~ NH2 (V) ( 2 ~ H2)m (CH2 ~ NH2)n wherein R4 and R5 respectively represent an alkyl group, chlorine atom or bromine atom and Z represents an alkylene group, -O-, -NII-, -S:, -SO2-, -COO-, -CONH-, -OCOO-, or -COOCO- and k + Q is an integer of 1 to ~ and m and n respectively represent 0 or an integer of 1 to 5. In the formula (V)~ when m or n is an integer of 2 or more, the aromatic amines include the compounds having p-anilinomethyl substituent group whose hydrogen on the ring is ~0 further substituted with p-anilinomethyl group as the complex substituents or a mixture thereof. Suitable aromatic amines .
include aniline, ~-toluidine, p-toluidine, chloroaniline, bromo-aniline, aminochlorotoluene, aminoxylene, aminoethylbenzene, amino- `
diphenylether, aminodiphenylsulfone, aminodiphenylester, amino~
benzyanilide, aminodiphenylsulfide diaminodiphenylether, diamino-diphenylmethane, diaminodiphenylester, diaminobenzanilide, diaminodiphenylsulfone and diaminodiphenylsulfide. The poly (phenylmethylene)polyamine having the formula (V) is preferably a mixture of the polyamines having an average total of m + n of 0.5 to 5. These aromatic amines are used in the form of a single com-pound or as a mixture thereof.
The maleic anhydride or maleic anhydride anhydride derivatives have the formula //
HC C
/--C~

wherein Rl represents hydrogen atom or an alkyl group and which are, for example, maleic anhydride and citraconic anhydride.
The cyclic acid anhydrides not having an unsaturated double bond which are used for proudcing the second maleimide compound have the formula Il .
/~
\ /
:' O ,.
wherein R6 represents CH2 -~ , ~ or CH2 -and which are, for example, succinic anhydride, phthalic anhydride, hexahydrophthalic anhydride and glutaric anhydride.
The second maleimide compounds can be obtained by introducing a maleimide group or the other imide group into the amino group of the aromatic amine. The amount of the maleic anhydride, or the derivative thereof and the cyclic acid anhydride not having an unsaturated double bond usually corresponds to the amino group of the aromatic amine, because the acid anhydride -stoichiometrically reacts with the amino group of the aromatic amine. The ratio of the maleic anhydride or derivative thereof to `
the cyclic acid anhydride not having an unsaturated double bond depends on the purpose of the second maleimide compound and it is `~
usually in a range of 2:8 to 8:2 by weight. It is preferable to include 0.5 to 3.0 preferably 0.8 to 2.0 of maleimido group as average in one molecule of the second maleimide. The ratio is - i ~: . , ` , selected depending upon the number of the amino groups of the aromatic amine. When the number of the maleimido group of the second maleimide compound is less than 0.5, the melting point of the imide compound is higher. When such maleimide compound is used as a vinyl monomer which is polymerizable, the content of ~he unreacted components in the dispersion is too high and -the electrical and mechanical properties may be inferior. When the number of the maleimide groups of the second maleimide compound is more than 3.0, the crosslinkage density of the baked resin is too high and by the baked resin may be brittle.
The ratio of the first maleimide compound to the second maleimide compound is not critical and the composition comprises usually 0 to 95 wt. part of the first maleimide compound and lO0 to S wt. parts of the second maleimide compound. The heat resistance and the mechanical characteristics of the object baked resin can be improved by increasing the ratio of the second maleimide compound. Accordingly, the content of the second maleimide can be selected as desired. The first maleimide include commercially available ones which are unexpensive. When the economical problem is important, the content of the first maleimide is increased. Even though the amount of the second maleimide compound is less than 5 wt. parts, the effect of the second maleimide compound can be anticipated. Even though lO0 wt.
parts of the first maleimide compound is used, the baked resin '~r' having superior characteristics can be obtained in comparison with the conventional resins.
The epoxy resins used in the present invention include the following compounds.
It is possible to add suitable amount of an epoxy compound having one cyclic or chained epoxy group in the molecule.
The epoxy compounds having a cyclic epoxy group are compounds having 1,2-epoxy group such as epoxidized diolefins, dienes, .

cyclic cienes and diolefinic unsatura-ted carboxylic acid esters.
The commercially available epoxy compounds include Chissonox 221, 201, 206, 269 and 289 (a trademark of Chisso K.K.) and Araldite CY-179, 178, 181,185 and 175 (a trademark of Ciba-Geigy). The compounds having a chained epoxy group include polyglycidyl ethers and polyglycidyl esters. The polyglycidyl ethers can be produced by a condensation of epichloxohydrin or ~-methyl epichlorohydrin with an aliphatic diol, a polyhydric alcohol, a bisphenol, phenol-novolak or cresol-novalak under alkaline condensation conditions.
The commercially available epoxy compounds include Epikote 826, 828, 834, 1001 and 1004 (trademarks of Shell Co.) and DEN 431 and 438 (trademarks of Dow Chemical Co.) Araldite CY-250 and 255 (trademarks ofChiba-Geigy).The polyglycidyl esters can be produced by reacting a dicarboxylic acid with epichlorohydrine or ~-methyl epichlorohydrine in an alkaline condition. The commercially available epoxy compounds include Araldite CY-183 (a trademark of Ciba-Geigy), Epikote 190 and 191 (trademarks of Shell Co.), Lekutherm X-100 (a trademark of sayer) and Epikone 200 and 499 (trademarks of Dainippon Ink Color). ~ ;
~0 Suitable monoepoxides which may be used as epoxy compound include phenylglycidyl ether, allylglycidyl ether, cresylglycidyl ether, butylglycidyl ether, styreneoxide, p-butylphenolglycidyl ether, cyclohexenevinyl monoxide, glycidyl methacrylate, dipentenemonoxide and octyleneoxide. A diepoxide can also be used. Suitable diepoxide diluents include butadiene- ;
oxide, dimethylmethanedioxide, diglycidyl ether, butanediol diglycidyl ether, diethyleneglycol diglycidyl ether, vinylcyclo-hexene dioxide, divinylbenzenedioxide, bix(2,3-epoxycyclopental) ether, 3,4-epoxy-6-methylcyclohexyl methyl-3,4-epoxymethylcyclo-hexene carboxylate, resorcineglycidyl ether, 2-glycidylphenyl-glycidyl ether and 2,6-diglycidylphenylglycidyl ether.
The hardeners for the epoxy compound used in theresin of the present invention include acid anhydrides having the formula R\ /

Il CH3 CH~, CH3~, wherein R7 represents -CH=CH- . -CH2-CH2- or C12H23-C-It is possible to optionally incorporate salts and chelate compounds such as tricresyl borate, triethanolamine tita-nite, cobalt acetylacetate, zinc octylate, zinc acetylacetate and stanic octylate, and complexes of an amine and Lewis acid such as BF3, BCQ3, AsF5 and SbF5; or metalloolefins such as ferrocene.
The amount of the hardener to the epoxy resin is not critical and can be selected as desired. It is preferable to combine 20 to 95 wt.parts of the epoxy resin including the hardener with 80 to 5 wt.parts of the mixture of the first maleimide compound and the second maleimide compound. When the content of the mixture of the first and second maleimide compounds is less than 5 wt.parts, the heat resistance of the baked resin is insufficient, whereas when it is more than 80 wt.parts, the heat resistance is sufficiently high but the mechanical characteristics are inferior.

The phenoxy resins having the unit formula - CH
~0~ C ~30-CH2-CI H-CH2Jn which have a molecular weight of about 10,000 to 60,000 are pre-ferably used in the present invention. The phenoxy resin is incorporated in an amount of 0 to 10 wt.parts, preferably 0~5 to 10 wt.parts per 100 wt.parts of the resin composition of the first . .
_g_ and second maleimide compounds and the epoxy resin. When the phen~
oxy resin is incorporated, the resulting ba~ed resin has improved flexibility and cracking resistance. When the resin is used as a impregnation type varnish, the impregnating properties are improved. Although the resin composition having excellent characteristics can be obtained by incorporating less than 0.5 wt.part of the phenoxy resin, the effect of the pheno~y resin is not clearly shown. The minimum amount of the phenoxy resin is determined by the purpose of its application. However, when the content of the phenoxy resin is more than 10 wt.parts, a viscosl-ty of the composition is too high and the processability in the cast-ing and impregnating operation is inferior.
The heat resistant resin compositions of the present invention are of a non-solvent type and form the baked resins having significant heat resistance, significant adhesiveness for other materials low shrinkage, high flexibility and high electric insulation. The resin compositions can be used as impregnation type varnishes for electric parts, resins for casting, resins for lamination and other various applications.
~0 Other additives such as fillers and pigments may be incorporated.
The present invention will be further illustrated by ~-way of the following Examples.
In the Examples, the second maleimide compounds M-2A, B, C and D were produced by the conventional method using the components shown in the following Table-l.

-10- ' . .

Table l (mole) _ 4,4'-diaminodiphenylmethane l.0 l .0 1.0 .
4,4'-diaminodiphenylether _ l. O _ 0.5 ., aniline 0.2 _ _ 0.5 poly(phenylmethylene) _ _ l.0 l.0 polyamine (formula V n-l. 0 ) _ maleic anhydride 1.1 2.5 3. t) 3.2 phthalic anhydride _ _ l.0 hexahydrophthalic anhydridel . l 1.5 _ l 0.8 _ . _ .,~
EXAMPLE 1:
To 48 wt.parts of the epoxy compound (supplied under the trademark Epikote 828) was added 17 wt.parts of the second malei-mide M-2A shown in Table-l which was completely dissolved at 140 C. The mixture was cooled to 60C. 38 wt.parts of methyl tetra-hydrophthalic anhydride and 1 wt.part of DMP-30 were added and the 20 mixture was cooled to the room temperature to obtai n a resin com-position. The resin composition was a varnish stable at room temperature which did not form any precipitate on standing for 50 hours . The viscosity of the composition measured by srookf ield type viscometer was 2.0 poises at 60C. I'he flexural strength and flexural modulus of the baked product, measured by Instron univer-sal tester were respectively 13.5 Kg/mm2 at 25C and 290 Kg/mm2 at 25C . The baked resin had a weight loss of 4.8% at 240 C over 250 hours, a heat distortion temperature of 135C and an adhesive strength of 14.0 Kg at 25C.

30 EXAMPLES 2 TO 4:
In accordance with the process of Example 1, varnishes having compositions shown in Table 2 were prepared and the tests of the baked products were carried out.
The results are shown in Table 2.
Table 2 Example . - 2_ 3 ~
Epoxy compound: * Epikote 8 ~8 2 5 * Epikote 834 57 28 * Chissonox 221 15 Cresylglycidyl ether 5 Methyl tetrahydre~hthalic anhydride35 10 36 Second maleimide compound: M- 2A 8s O

_ Viscosity (70C: poise) 2. 0 10. 0 5. 5 -_ ~, Flexural strength (2 5C: Kg/mm2) 14 . O 18 . O 16 . O
_ _ : -;
Flexural modulus 280. 0 330. 0 295 -( 2 5C Kg /mm2 ) . _ . : :.
Heat distortion temp. (C) 140 16 5. 0 1 55 , Adhesive strength (25C: Kg) 15. 5 16. 5 16. 0 _ . _ 20 Weight loss (Yo) (240C 250 hours) 4.8 2.4 3.2 1 ~, * trademarks To 47 wt.parts of the epoxy compound (supplied under the ~-trademark Epikote 828) was added 2 wt.parts of the phenoxy resin (M.W. 30, 000) and was completely dissolved at 150 to 160C. Then 20 wt.parts of the second maleimide compound (M-2A) was dissolved in the mixture at 120 to 130C. The mixture was cooled to 60C.
37 wt.parts of methyl tetrahydrophthalic acid and 1 wt.part of ' zinc octanate were added and the mixture was cooled to the room 30 temperature to obtain a resin composition.
The resin composition was stable without forming any precipitate on leaving at the room temperature for 50 hours.
:

. .
.. . . . .

~89~

EXAMPLES 6 TO l 0:

In accordance with the process of Example 5, the varnishes having the compositions shown in Table 3 were prepared and the tests of the baked products were carried out~
The results are shown in Table 3.

REFERENC:ES 1 AND 2:
.~
In accordance with the process of Example l, the varnishes having the compositions shown in Table 3 were prepared and the tests of the baked products were carried out. The results are shown in Table- 3 .

` 30 ~ _ o _ _ -0 _ _ _ . _ d~' a~ _ _ _ _ _ _ _ I ~D U~. .~
: `

- o - - - - ---- o o ~ ~ C`3 CO ~ O O ~ I /~ ' ~ c`~ ~ - -- - - -- - - - u~. :
_. a~ ~ _, o, _ _ _ ~ _ u~ _ O ~0 ~:

~ ~ o o o ~ o -( c~ u~
r~ _ c~ _ _ c~ _ _ _ _ _ ~0 O _ cr~t~ O O O L~ O Ct~~ ~ ~:
~ ~ c~ c~ c~ -l E~ _ . _ _ _ _ _ _ _ o ~ ~., CD c~ O 0~ C~ ~ '~ _l d~ ' : ~

~ ~ ~ ~ ~ ~ e3a ~ ~~
~0 ~v ~ ~ ~ O ~ ~ ~ ~ ~ m v ~ . ~ . O v~ ~ ~

~ ~ * t~ _ ~ ~ls '~'3 C C , C R ~ SI~ ~ ~ ~ -` ', "' '`'~` `

~`' ~ ;-;
.
~, -14- :.

- - o - o o _ N O O N
~cJ ~1~ i~ L~ ~
i ~ ~ ~ Y, . .
. .

EXAMPLE 11:
To 47 wt.parts of the epoxy compound (supplied under the trademark Epikote 828) was added 2 wt.parts of the phenoxy resin (M.W. 30,000) and was completely dissolved at 150 to 160C.
Then, 2 wt.parts of the second maleimide compound (M-2A) and 13 wt.parts of the firs~ maleimide N,N'-(methylene-di-p-phenylene) dimaleimide were dissolved in the mixture at 120 to 130C and then, cooled to 60C. 37 wt.parts of methylhexahydrophthalic anhydride and 2 wt.parts of zinc octylate were added and the mixture was cooled to the room temperature to obtain a resin composition. The resin composition was stable without forming any precipitate on leaving at the room temperature for 50hours. The resin composition had a viscosity of 0.1 poise at 70C. The baked product had a flexural strength of 13.5 Kg/mm2 at 25C a flexural modulus of 330 Kg/mm2 at 25C and a weight loss of 6.5%
at 240C for 250 hours.
EXAMPLE 12: ;
To 47 wt.parts of the epoxy compound (supplied under the trademark Epikote 828) was added 1 wt.part of the phenoxy resin (M.W. 30,Q00) and was completely dissolved at 150 to 160C.
Then, 10 wt.parts of the second maleimide compound (M-2B) and 5 wt.parts of the first maleimide compound N,N'-(methylene di-p-phenylene) dimaleimide were dissolved and cooled to 60C. 38 wt.
parts of methyl tetrahydrophthalic anhydride and 1 wt.part of zinc octylate were added and the mixture was cooled to the room temperature to obtain a resin composition. The resin composition was stable without forming any precipitate on leaving at the room temperature for 50 hours.
The resin composition had a viscosity of 0.8 poise at 70C. The baked product had a flexural strength of 13.0 Kg/mm2 at 25C and a weight loss of 7.0% at 240C for 250 hours.
''

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A heat resistant resin composition, comprising:
a) 80 to 5 parts by weight of a mixture of i) 0 to 95 parts by weight of a first maleimide compound selected from the group con-sisting of and wherein R1 is alkyl, R2 is a monovalent organic group, R3 is a divalent organic group and n is an average of 0.5 to 5 and ii) 100 to 5 parts by weight of a second maleimide compound containing 0.5 to 3.0 maleimide groups and formed by reacting an aromatic amine selected from the group consisting of aniline, o-toluidine, p-toluidine, chloroaniline, bromoaniline, aminochlorotoluene, amin-oxylene, aminoethylbenzene, amonodiphenylether, aminodiphenylsulfone, aminodiphenylester, aminodiphenylsulfide.

, , , wherein R4 and R5 represent alkyl, chlorine or bromine; Z is alkylene, -O-, -NH-, -S-, -SO2-, -COO-, -CONH-, -OCOO- or -COOCO-;
k + 1 represents an integer of 1 to 4 and m and n each represents 0 or an integer of 1 to 5 and mixtures thereof with a maleic an-hydride compound of the formula:

wherein R1 is hydrogen or alkyl and a cyclic anhydride compound of the formula:

wherein R6 is , or , the weight ratio of said maleic anhydride compound to said cyclic anhydride compound ranging from 2:8 to 8:2 and the amounts of said aromatic amine and maleic anhydride compound and cyclic anhydride being such that the total amount of anhydride is the stoichio-metric amount necessary to react with the amino groups of said aromatic amine; and b) 20 to 95 parts by weight of a diepoxy compound.

2. The heat resistant resin composition according to claim 1 which further comprises from 0 to 10 parts by weight of phenoxy resin incorporated in 100 parts by weight of the composition of claim 1.

3. The heat resistant composition according to claim 1 or 2 wherein the aromatic amine is a mixture of an aromatic monoamine and an aromatic polyamine.

4. The heat resistant resin composition according to claim 1 or 2 wherein R2 represents an alkyl, aryl, aralkyl or haloalkyl, haloaryl or haloaralkyl group.

5. The heat resistant resin composition according to claim 1 or 2 wherein R3 represents an alkylene, arylene or aralkyl-ene group.

6. A heat resistant resin composition according to claim 1 or 2, wherein the cyclic anhydride is succinic anhy-dride, phthalic anhydride, hexahydrophthalic anhydride or glutaric anhydride.

7. A heat resistant resin composition according to claim 1 or 2, wherein the second maleimide compound has average 0.5 to 3.0 maleimido group per molecule.

8. The heat resistant resin composition according to claim 1 wherein said diepoxy compound is butadieneoxide, dimethyl-methanedioxide, diglycidylether, butanedioldiglycidylether, di-ethyleneglycoldiglycidylether, vinylcyclohexenedioxide, divinyl-benzenedioxide, bis(2,3-epoxycyclopental)ether, 3,4-epoxy-6-methyl-cyclohexylmethyl-3,4-epoxymethylcyclohexenecarboxylate, resorcine-glycidylether, 2-glycidylphenylglycidylether or 2,6-diglycidyl-phenylglycidylether.

9. The heat resistant resin composition according to claim 2, wherein said phenoxy resin has the formula:

where n is from about 40 to 210 and which has a molecular weight ranging from 10,000 to 60,000.

10. A resin as claimed in claim 1, in which the first maleimide is selected from N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-hexylmaleimide, N-octyl-maleimide, N-dodecylmaleimide, N-phenylmaleimide, N-p-tolyl-maleimide, N-m-tolylmaleimide, N-o-naphthylmaleimide, N-benzyl-maleimide or a mixture thereof.

11. A resin as claimed in claim 10, in which the first maleimide is selected from N,N'-(methylene-di-p-phenylene) dimale-imide, N,N'-(oxy-di-p-phenylene)dimaleimide, N,N'-m-phenylene-dimaleimide, N,N'-p-phenylenedimaleimide, N,N'-2,4-tolylene-di-maleimide, N,N'-2,6-tolylenediamaleimide, N,N'-m-xylenedimaleimide, N,N'-p-xylenedimaleimide, N,N'-oxydipropylenedimaleimide, ethylene-dioxybis-N-propylmaleimide, oxybis-N-ethylmaleimide, N,N'-ethylene-dimaleimide, N,N'-trimethylenedimaleimide, N,N'-tetramethylene-dimaleimide, N,N'-hexamethylenedimaleimide, N,N'-dodecamethylene-dimaleimide and mixtures thereof.

12. The heat resistant resin composition according to claim 1, which further comprises a hardener of the formula:

wherein R7 is , , , -CH = CH-, -CH2C2 or C12H23-CH-CH2-.

13. The heat resistant resin composition according to claim 1 wherein said diepoxy compounds are selected from the following compounds: epoxy compounds having a cyclic 1,2-epoxy group, polyglycidyl ethers and polyglycidyl esters.

14. A composition as claimed in claim 13 in which the polyglycidyl ethers are produced by alkaline condensation of epichlorohydrin or .beta.-methyl epichlorohydrin with an aliphatic diol, a polyhydric alcohol, a bisphenol, phenol-novolak or cresol-novolak and the polyglycidyl esters are produced by reacting a dicarboxylic acid with epichlorohydrin or .beta.-methyl epichlorohydrin under alkaline conditions.

15. A composition as claimed in claim 13 in which the cyclic compounds having a 1,2-epoxy group is selected from epoxidized diolefins, dienes, cyclic dienes and diolefinic unsat-urated carboxylic acid esters.