Thermosetting compounds, cured product thereof and method of preparing the thermosetting compound

A novel thermosetting compound which is speedily curable, generates no by-products during curing and gives cured products having excellent heat resistance and inflammability. A thermosetting compound characterized in containing, per molecule, at least one structural unit represented by the formula (A) and at least one structural unit represented by the formula (B) in a (A)/(B) molar ratio of 1/0.25 to 1/9, said structural units being bonded directly or via at least one organic group with one another; ##STR1## wherein R.sup.1 is a methyl group, a cyclohexyl group, a nonsubstituted phenyl group or a phenyl group substituted with at least one substituent, and each hydrogen atom on the aromatic rings of (A) and (B), except for one of hydrogen atoms on ortho-positions of the hydroxy group in the aromatic ring of (A), may optionally be replaced with a substituent.

BACKGROUND OF THE INVENTION 
The present invention relates to novel thermosetting compounds which hardly 
generate volatile by-products on curing, cured products thereof and a 
method for manufacturing the thermosetting compounds. 
Thermosetting resins, such as phenolic resins, melamine resins, epoxy 
resins, unsaturated polyester resins and bis-maleimide resins, are widely 
used in many industrial fields due to the heat resistance originated from 
their thermosetting property and to their reliability. These resins 
however suffer their respective disadvantages, for example, the generation 
of volatile by-products on curing of phenolic resins or melamine resins, 
the poor inflammability of epoxy resins and unsaturated polyester resins 
and the extremely high price of bis-maleimide resins, and, in practical 
use, such disadvantages have unavoidably been tolerated depending on their 
uses. To solve this problem, there have been made attempts to develop 
novel thermosetting resins free from such disadvantages. 
One of the attempts resulted in the development of dihydrobenzoxazine 
compounds (refer to the specification of Japanese Patent Unexamined 
Publication No. 49-47378 and the specification of U.S. Pat. No. 
5,152,939). The compounds are cured by the ring-opening polymerization of 
the benzoxazine rings, to cause little generation of volatile matters on 
thermosetting. 
However, the curing reaction brings about not so long extension of 
molecular chains (Polym. Sci. Technol., 31, p.27-49, 1985) and inadequate 
density of cross-linking, so that softening or thermal deterioration 
occurs over 200.degree. C. 
It is also known that the ring-opening polymerization takes 
disadvantageously longer curing time as compared with the curing reaction 
of conventional phenolic resins, resulting in low productivity that limits 
the industrial use of the compounds. 
SUMMARY OF THE INVENTION 
The present invention is to overcome the above described problems and to 
provide a thermosetting compound which is characterized in containing, per 
molecule, at least one structural unit represented by the formula (A) and 
at least one structural unit represented by the formula (B) in a (A)/(B) 
molar ratio of 1/0.25 to 1/9, said structural units being bonded directly 
or via at least one organic group with one another; 
##STR2## 
wherein R.sup.1 is a methyl group, a cyclohexyl group, a nonsubstituted 
phenyl group or a phenyl group substituted with at least one substituent, 
and each hydrogen atom on the aromatic rings of (A) and (B), except for 
one of hydrogen atoms on ortho-positions to the hydroxy group in the 
aromatic ring of (A), may optionally be replaced with a substituent.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the following, the present invention is explained in detail. 
The thermosetting compound of the present invention is characterized in 
containing, per molecule, at least one structural unit represented by the 
formula (A) and at least one structural unit represented by the formula 
(B) in a (A)/(B) molar ratio of 1/0.25 to 1/9, said structural units being 
bonded directly or via at least one organic group with one another; 
##STR3## 
wherein R.sup.1 is a methyl group, a cyclohexyl group, a nonsubstituted 
phenyl group or a phenyl group substituted with at least one substituent 
such as a methyl group, a methoxy group, etc., and each hydrogen atom on 
the aromatic rings of (A) and (B), except for one of hydrogen atoms on 
ortho-positions to the hydroxy group in the aromatic ring of (A), may 
optionally be replaced with a substituent such as a methyl group, a 
t-buthyl group, a halogen atom, etc. 
In the thermosetting compound of the present invention, the molar ratio of 
(A)/(B) is 1/0.25 to 1/9, preferably 1/0.67 to 1/9, more preferably almost 
1/1. This is for the reason that when said molar ratio is out of 
1/0.25-1/9, the thermosetting compound may have poor properties of curing 
time or mechanical strength and heat resistance. 
In the thermosetting compound of the present invention, each structural 
unit, namely, (A) and (B), may be contained in various proportions per 
molecule. However, when the number of the structural units (A) per 
molecule is m and the number of the structural units (B) per molecule is 
n, it is necessary to satisfy m.gtoreq.1, n.gtoreq.1 and 
10.gtoreq.m+n.gtoreq.2, and it is preferable that 10.gtoreq.m+n.gtoreq.3. 
The reason is that the structural units (A) and (B) are previously bonded 
with one another by stable bonds to make a proper chain length, which 
imparts the cured products with good properties. 
The structural units may be independently bonded directly or via at least 
one organic group with one another. Some examples of the organic group 
include alkylene groups and divalent aromatic groups. Some examples of the 
alkylene groups include the group represented by the formula (C) and a 
long chain alkylene group having 5 to 30 carbon atoms; 
##STR4## 
wherein R.sup.2 is a hydrogen atom, a methyl group, an ethyl group, a 
propyl group, an isopropyl group, a nonsubstituted phenyl group or a 
phenyl group substituted with at least one substituent such as a methyl 
group, a carboxyl group, etc. Some examples of the divalent aromatic 
groups include phenylene, xylylene and tolylene. 
Each organic group may be the same or different. 
The above organic groups may be inserted into the structural units as a 
series of two or more organic groups. 
So long as the thermosetting compound of the present invention does not 
provide a remarkable degradation of curing speed, mechanical strength and 
heat resistance, it may contain other component than the structural units 
represented by the formulae (A) and (B), and the above organic group. 
The thermosetting compound of the present invention can be manufactured by 
reacting primary amine and formaldehyde with a compound which contains at 
least two hydroxyphenylene groups per molecule, wherein on each 
hydroxyphenylene group a hydrogen atom is bonded at at least one 
ortho-position to the hydroxyl group (hereinafter, referred to as 
"compound containing the reactive hydroxyphenylene groups"), said primary 
amine being 0.2 to 0.9 moles, preferably 0.4 to 0.9 moles, more preferably 
0.5 to 0.7 moles, and said formaldehyde being at least double the molar 
quantity of the amine, based on one mole of the hydroxyl groups of the 
hydroxyphenylene groups on said compound containing the reactive 
hydroxyphenylene groups. 
The formaldehyde is used at least double the molar quantity of the amine 
and may be used in various proportions so long as it does not provide to 
degrade the efficiency of drying remarkably in the drying step mentioned 
below. 
Concretely, the objective compound is prepared by adding a mixture of the 
primary amine and the compound containing the reactive hydroxyphenylene 
groups into the formaldehyde heated to 70.degree. C. or higher, carrying 
out a reaction for 20 minutes to two hours at 70 to 110.degree. C., 
preferably 90 to 100.degree. C., and then drying the product in vacuum at 
120.degree. C. or lower. 
It is essential for the reaction to use 0.2 to 0.9 moles of the primary 
amine and to use formaldehyde in an amount at least double the molar 
quantity of the primary amine, based on one mole of the hydroxyl groups of 
the reactive hydroxyphenylene groups. Less than 0.2 moles of the primary 
amine cannot make enough dihydrobenzoxazine rings to give sufficient 
density of cross-linking on curing the obtained compound, and the cured 
product will be poor in mechanical strength. More than 0.9 moles of the 
primary amine will give compounds which disadvantageously behave in a 
manner similar to that of the conventional dihydrobenzoxazine compounds, 
in other words, give compounds which take long curing time. 
The ratio of the primary amine to the compound containing the reactive 
hydroxyphenylene groups is determined as follows. A compound containing 
the hydroxyphenylene groups is reacted with a primary amine that is in the 
amount equimolar with the total hydroxyl groups of the compound, to give a 
product. The amount of the reacted hydroxyl groups of the compound, namely 
the reactive hydroxyl groups in the compound containing the 
hydroxyphenylene groups, is calculated from the weight of the product, and 
the molar ratio of the primary amine is determined based on the amount of 
the reactive hydroxyl groups. 
Some examples of the compound containing at least two reactive 
hydroxyphenylene groups per molecule include phenol novolac resins, resol 
resins, phenol-modified xylene resins, alkylphenol resins, 
melamine-phenolic resins, phenol-modified polybutadienes and 
xylylene-modified phenolic resins. As the phenol novolac resins, for 
example, there may be used the phenol novolac resins having number average 
molecular weights of 200 to 3000. 
It is not essential but preferable that ortho-positions of hydroxyl groups, 
where crosslinking is to be occur, are not substituted in view of the 
properties of cured products, and in case of phenol novolac resins, the 
preferred are so-called random novolac resins, which have low ratios of 
ortho-substitution and relatively low number average molecular weights. 
Novolacs with larger molecular weights, on one hand, give 
dihydrobenzoxazine compounds with larger molecular weights, but, on the 
other hand, cause problems of decreasing flowability during molding and 
increasing difficulty in controlling curing speed. 
The above-described resins are mixtures of compounds containing their 
respective numbers of reactive hydroxyphenylene groups per molecule, and 
during the preparation, a part of the occurring thermosetting compounds 
are polymerized with each other. The resulting thermosetting compound of 
the present invention, therefore, is a mixture of compounds with their 
respective values of m and n. It is impossible at present to separate the 
compounds with their respective values of m and n. 
Some examples of the primary amine include aliphatic amines and aromatic 
amines. Aliphatic amines give thermosetting compounds which are quickly 
curable but give cured products with somewhat inferior heat resistance, 
and aromatic amines give thermosetting compounds which give cured products 
with good heat resistance but take longer curing time. 
Some examples of the aliphatic amine include a methylamine and a 
cyclohexylamine, and some examples of the aromatic amine include a 
nonsubstituted aniline and anilines substituted with at least one 
substituent such as a methyl group, a methoxy group, etc. Among them, a 
nonsubstituted aniline is preferred for actual industrial use. 
These primary amines may be used singly or as a mixture thereof. 
The thermosetting compound of the present invention is cured by heating at 
150.degree. C. or higher, preferably at 170 to 220.degree. C. in the 
absence of catalysts or curing agents without generating by-products. 
Further, the thermosetting compound can be cured more quickly than the 
conventional dihydrobenzoxazine compounds. 
The curing of the dihydrobenzoxazine compounds proceeds by the interaction 
between hydroxyl groups neighbored at ortho-positions by hydrogen atoms 
and dihydrobenzoxazine rings. The thermosetting compound of the present 
invention contains in its molecule hydroxyl groups neighbored at 
ortho-positions by hydrogen atoms and dihydrobenzoxazine rings both in 
proper amounts. This seems to make the curing reaction occur easily. 
The compound of the present invention contains in molecule 
dihydrobenzoxazine rings in a smaller ratio as compared with the 
conventional dihydrobenzoxazines. The compound containing per molecule at 
least two reactive hydroxyphenylene groups, which are used for the 
preparation of the compound of the present invention, has essentially high 
heat resistance and inflammability. The characteristics remain in the 
compound of the present invention and endow it with high heat resistance 
and inflammability. 
The thermosetting compound of the present invention can be used as a 
component of a molding material. 
A molding material can be manufactured, for example, by mixing the 
thermosetting compound of the present invention and a glass fiber, etc., 
kneading the mixture and pulverizing it. A molded product can be 
manufactured by heating and curing the molding material in a mold. 
The thermosetting compound of the present invention can be used as a 
component of a composition used for manufacturing a varnish. This varnish 
can be manufactured by dissolving the thermosetting compound of the 
present invention, and if necessary, an epoxy resin or epoxy resins, etc. 
in a solvent or solvents such as methyl ethyl ketone, methylcellosolve, 
etc. 
The present invention will be described in detail with reference to the 
following Examples, which however are not to be construed to limit the 
scope of the invention. 
EXAMPLE 1 
(1) Synthesis of a Phenol Novolac Resin 
In 5-liter flask were placed 1.9 kg of phenol, 1.0 kg of formalin (37% 
aqueous solution) and 4 g of oxalic acid, and were reacted at reflux 
temperature for 6 hours. Then, the internal pressure was reduced to 6666.1 
Pa or lower to remove unreacted phenol and water. The resulting resin had 
a softening point of 84.degree. C. (ring and ball method) and a tri- or 
more nuclear products/dinuclear product ratio of 82/18 (the ratio of peak 
areas measured by gel-permeation chromatography). FIG. 1 shows the 
molecular weight distribution curve of the obtained phenol novolac resin. 
This molecular weight distribution curve was measured by liquid 
chromatography. The horizontal axis shows the retention time, that is, 
molecular weight. The longer the retention time is, the smaller the 
molecular weight is. The vertical axis shows the intensity measured by the 
detector in the liquid chromatography, that is, number of molecule. 
(2) Introduction of Dihydrobenzoxazine Rings 
1.70 kg (corresponding to 16 moles of hydroxyl groups) of the phenol 
novolac resin synthesized as above was mixed with 0.93 kg (10 moles) of 
aniline, followed by stirring at 80.degree. C. for 5 hours to form a 
uniform solution mixture. 1.62 kg of formalin was placed in a 5-liter 
flask and was heated to 90.degree. C., and the novolac/aniline mixture was 
added thereto over a 30 minutes interval. After the completion of the 
addition, the mixture was heated at the reflux temperature for 30 minutes, 
and the condensed water was removed at a reduced pressure of 6666.1 Pa or 
lower at 100.degree. C. for two hours, to give a thermosetting compound in 
which 71% of reactive hydroxyl groups had been converted into 
dihydrobenzoxazine rings. FIG. 2 shows the molecular weight distribution 
curve measured in the same manner as FIG. 1, FIG. 8 shows the IR spectrum, 
and FIG. 12 shows the NMR spectrum of the obtained thermosetting compound. 
The amount of the reactive hydroxyl groups was calculated as follows. 
1.70 kg (corresponding to 16 moles of hydroxyl groups) of the phenol 
novolac resin synthesized in (1) was reacted with 1.49 kg (16 moles) of 
aniline and 2.59 kg of formalin in the same manner, to synthesize another 
thermosetting compounds in which all the reactive hydroxyl groups had been 
converted into dihydrobenzoxazine rings. The excessive aniline and 
formalin were removed during drying, to give 3.34 kg of the thermosetting 
compound. This means that 14 moles of the hydroxyl groups of the phenol 
novolac resin underwent the reaction to form dihydrobenzoxazine rings. 
Accordingly, the ratio of dihydrobenzoxazine rings converted from the 
reactive hydroxyl groups is estimated to be 71% (10 moles/14 moles). 
(3) Curing of the Thermosetting Compound 
The thermosetting compound synthesized as above was pulverized, was filled 
in a mold of 100.times.100.times.4 mm in internal sizes, and was heated 
and pressed at 200.degree. C. at 1.96 MPa for 10 minutes, to give a cured 
product. The properties of the cured product are listed in Table 1. 
EXAMPLE 2 
(1) Synthesis of a Phenol Novolac Resin 
Into a 5-liter flask were placed 1.90 kg of phenol, 1.15 kg of formalin 
(37% aqueous solution) and 4 g of oxalic acid, and a phenol novolac resin 
was synthesized in the same manner as in Example 1. The resulting resin 
had a softening point of 89.degree. C. (ring and ball method) and a tri- 
or more-nuclear products/dinuclear product ratio of 89/11 (the ratio of 
peak areas measured by gel-permeation chromatography). FIG. 3 shows the 
molecular weight distribution curve of the obtained phenol novolac resin 
and was measured in the same manner as FIG. 1. 
(2) Introduction of Dihydrobenzoxazine Rings 
The introduction of dihydrobenzoxazine rings was carried out in the same 
manner as in Example 1 by using 1.70 kg of the phenol novolac resin (total 
hydroxyl groups: 16 moles, reactive hydroxyl groups: 13.3 moles), 0.93 kg 
(10 moles) of aniline and 1.62 kg (20 moles) of formalin, to give a 
thermosetting compound, wherein 75% of the reactive hydroxyl groups of the 
phenol novolac resin converted into dihydrobenzoxazine rings. FIG. 4 shows 
the molecular weight distribution curve measured in the same manner as 
FIG. 1, FIG. 9 shows the IR spectrum, and FIG. 13 shows the NMR spectrum 
of the obtained thermosetting compound. 
(3) Curing of the Thermosetting Compound 
A cured product was produced in the same manner as in Example 1. The 
properties of the cured product are listed in Table 1. 
EXAMPLE 3 
The procedure of Example 1 was repeated with the exception that 1.70 kg 
(corresponding to 10 moles of hydroxyl groups) of a xylylene-modified 
phenolic resin (produced by Mitsui Toatsu Chemicals, Inc., Trade name: 
MILEX XL-225-3L), 0.52 kg (5.6 moles) of aniline and 0.91 kg of formalin 
were used, to synthesize a thermosetting compound wherein 
dihydrobenzoxazine rings were introduced. FIG. 5 shows the molecular 
weight distribution curve of the starting xylylene-modified phenolic 
resin. FIG. 6 shows the molecular weight distribution curve, FIG. 10 shows 
the IR spectrum, and FIG. 14 shows the NMR spectrum of the obtained 
thermosetting compound wherein dihydrobenzoxazine rings had been 
introduced. FIG. 5 and FIG. 6 were measured in the same manner as FIG. 1. 
A cured product was produced in the same manner as in Example 1. 
As to the xylylene-modified phenolic resin, the amount of the reactive 
hydroxyl groups was calculated as follows. 
2.62 kg of a thermosetting compound wherein dihydrobenzoxazine rings were 
introduced was prepared by using 1.70 kg (corresponding to 10 moles of 
hydroxyl groups) of the xylylene-modified phenolic resin, 0.93 kg (10 
moles) of aniline and 1.62 kg of formalin. The excessive aniline and 
formalin were removed during drying. From the weight of the thermosetting 
compound, the amount of the reactive hydroxyl groups were calculated to be 
7.9 moles. Accordingly, the ratio of dihydrobenzoxazine rings converted 
from the reactive hydroxyl groups is estimated to be 71% (5.6 moles/7.9 
moles). The properties of the cured product are listed in Table 1. 
EXAMPLE 4 
The procedure of Example 1 was repeated with the exception that a mixture 
of 0.70 kg of aniline and 0.27 kg of toluidine was used in place of 
aniline, to obtain a thermosetting resin wherein dihydrobenzoxazine rings 
were introduced. The obtained thermosetting compound was resulted by the 
conversion of 71% of the reactive hydroxyl groups of the phenol novolac 
resin into dihydrobenzoxazine rings. FIG. 7 shows the molecular weight 
distribution curve measured in the same manner as FIG. 1, FIG. 11 shows 
the IR spectrum, and FIG. 15 shows the NMR spectrum of the obtained 
thermosetting compound. The properties of the cured product are listed in 
Table 1. 
EXAMPLE 5 
35% (% by weight, this is to be repeated in the following) of the 
thermosetting compound obtained in Example 1, 45% of a glass fiber of 10 
.mu.m in average fiber diameter, 18% of talc, 1% of zinc stearate, 0.5% of 
a silane coupling agent and 0.5% of carbon black were mixed, and the 
mixture was kneaded with heated mixing rolls at 95.degree. C. for three 
minutes and pulverized, to obtain a powdery composition. The composition 
was molded at a mold temperature of 200.degree. C., at 4.9 MPa for 10 
minutes, to obtain a molded product of a plate form. The properties of the 
cured product are listed in Table 1. 
Comparative Example 1 
A thermosetting compound wherein dihydrobenzoxazine rings were introduced 
was prepared in the same manner as in Example 1 with the exception that 
1.70 kg (corresponding to 16 moles of hydroxyl groups) of the phenol 
novolac resin synthesized in Example 1, 1.49 kg (16 moles) of aniline and 
2.59 kg of formalin were used. A cured product was produced by using the 
thermosetting compound in the same manner as in Example 1. The properties 
of the cured product are listed in Table 2. 
Comparative Example 2 
10 parts (parts by weight, this is to be repeated in the following) of 
hexamethylenetetramine was added to 100 parts of the phenol novolac resin 
synthesized in Example 1, and the mixture was cured in the same manner as 
in Example 1. The properties of the cured product are listed in Table 2. 
Comparative Example 3 
A resin was synthesized in a 10-liter flask in the same manner as in 
Example 1 by using 1.69 kg (18 moles) of phenol in place of the phenol 
novolac resin synthesized in Example 1, 1.67 kg (18 moles) of aniline and 
2.92 kg of formalin. 
When the resins was cured in the same manner as in Example 1, softening 
occurred remarkably at the time of release from the mold, and the 
measurements of mechanical properties could not be made. The cured product 
was very brittle, indicating the insufficient curing. The properties of 
the cured product are listed in Table 2. 
Comparative Example 4 
The procedure of Comparative Example 3 was repeated with the exception that 
the curing time was changed to one hour. Softening also occurred at the 
time of release from the mold but was slight as compared with that in 
Comparative Example 3. The properties of the cured product are listed in 
Table 2. 
Comparative Example 5 
As disclosed in Comparative Example 3, a resin was synthesized in the same 
manner as in Example 1 with the exception that 1.69 kg (18 moles) of 
phenol, 1.12 kg (12 moles) of aniline and 1.95 kg of formalin were used. 
When the thermosetting resin was cured in the same manner as in Example 1, 
softening also occurred at the time of release from the mold but was 
slight as compared with that in Comparative Example 3. 
In the evaluation of the properties of the cured products, mechanical 
properties were evaluated according to JIS K 6911, and heat resistance was 
evaluated by using a thermogravimetric thermomechanical analyzer, 
TG/DTA.TMA200 (produced by Seiko Electronic Industries, Ltd.). Flexural 
strength and Flexural modulus were measured at 23.degree. C. and at a 
bending rate of 2 mm/min, glass transition temperature and the 
weight-reducing temperature were measured in air at a temperature-raising 
rate of 5.degree. C./min, and inflammability was evaluated according to 
UL-94, by using plates of 3.6 mm thick. 
In the Tables, the parentheses bracketing the glass transition temperature 
of Example 5 mean obscurity, and the parentheses for Comparative Examples 
4 and 5 mean softening. 
TABLE 1 
__________________________________________________________________________ 
Example 1 
Example 2 
Example 3 
Example 4 
Example 5 
__________________________________________________________________________ 
Appearance of cured 
Red Red Yellow orange 
Red Black 
product Transparent Transparent Transparent Transparent 
Surface of cured Even Even Even Even Even 
product 
Flexural strength 171.5 158.8 137.2 160.7 258.7 
(MPa) 
Felxural modulus 5684 5782 4410 5684 18816 
(MPa) 
Glass transition 201 205 162 194 (220) 
temperature (.degree. C.) 
Temperature for 383 390 415 380 442 
5%-weight reduction 
(.degree. C.) 
Flammability (UL-94) V-0 V-0 V-0 V-0 V-0 
__________________________________________________________________________ 
TABLE 2 
__________________________________________________________________________ 
Comparative 
Comparative 
Comparative 
Comparative 
Comparative 
Example 1 Example 2 Example 3 Example 4 Example 5 
__________________________________________________________________________ 
Appearance of cured 
Red Brown Cloudy 
Red Red Black 
product Transparent Transparent Transparent 
Surface of cured Even Many minute Even Even Even 
product bubbles 
Flexural strength 149 29.4 Could not be Could not be Could not be 
(MPa) measured measured measured 
Felxural modulus 5390 3822 Could 
not be Could not be Could not be 
(MPa) measured measured measured 
Glass transition 155 Could not be 
Melted during (118) (127) 
temperature (.degree. C.) measured measurement 
Temperature for 325 302 310 312 321 
5%-weight reduction 
(.degree. C.) 
Flammability (UL-94) V-0 V-1 Melted during V-0 V-0 
measurement 
__________________________________________________________________________ 
Though the thermosetting compound of the Comparative Example 3 was not 
cured completely when the curing time was 10 minutes, the thermosetting 
compounds of the present invention were cured completely in 10 minutes. 
These results mean that the thermosetting compounds of the present 
invention are speedily curable. 
According to Tables 1 and 2, the temperatures for 5%-weight reduction of 
the cured products of the present invention are remarkably high comparing 
with those of the cured products of Comparative Examples 1-5. These 
results mean that the cured products of the present invention have 
excellent heat resistance comparing with those of conventional 
thermosetting resins. 
Further, the cured products of the present invention show "V-O" as the 
results of flammability (UL-94). These results mean that the flames of-the 
cured products of the present invention were disappeared remarkably soon, 
therefore, the cured products of the present invention have excellent 
flammabilities. 
Further, though the flexural strengthes and flexural moduluses of the cured 
products of Comparative Examples 3-5 are too weak, therefore, can not be 
measured, the cured products of the present invention have excellent 
flexural strengthes and flexural moduluses. These results mean that the 
cured products of the present inventions have excellent mechanical 
strengthes. 
Further, though the cured product of Comparative Example 2 has many minute 
bubbles in the surface, the cured products of the present invention have 
even surfaces. These results mean that the thermosetting compounds of the 
present invention generate no volatile matters during curing. 
The thermosetting compound of the present invention is speedily curable and 
generates no volatile matters during curing, and the cured product 
exhibits excellent heat resistance and inflammability. The thermosetting 
compound of the present invention, therefore, is useful as a high 
performance molding material, varnish, coating material, adhesive, 
encapsulating materials for semiconductors, and material for laminates, 
FRP(Fiber Reinforced Plastics) and carbon goods.