COMPOSES RESINEUX RESISTANTS AUX TEMPERATURES ELEVEES

HEAT RESISTANT RESIN COMPOSITION

Abrégé anglais

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.

Revendications

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
<IMG>
<IMG>
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.
17

<IMG>, <IMG>, <IMG>,
<IMG>
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:
<IMG>
wherein R1 is hydrogen or alkyl and a cyclic anhydride compound
of the formula:
<IMG> wherein R6 is <IMG> , <IMG> or <IMG>,
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-
18

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:
19

<IMG>
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:
<IMG> wherein R7 is <IMG> <IMG> <IMG>
<IMG>, <IMG>, <IMG>
<IMG>, -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.
21

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
R4
(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
--5--

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
-6-
- 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,
.
-7-

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
--8--

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-
CH2-
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
CH3 OH
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)
M- 2A M- 2B M- 2C M- 2D
_
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
DMP- 30 1 1
Second maleimide
compound: M- 2A 8s O
M-2B 80
M- 2C 1 0
_
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
EXAMPLE 5-
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.
:
-1 2 -
. .
.. . . . .

~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
--13--

~ _ 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,
--15--
. .
. .

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.
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