A highly oxygen-permeable heat-resistant material consisting essentially of a polymer obtained by polymerizing a polymerizable component containing a silicon-containing stilbene derivative of the formula (I): ##STR1## wherein each of R.sup.1 and R.sup.2 which are independent of each other, is a hydrogen atom or a group of the formula (II): EQU --Si.sub.p O.sub.p-1 (CH.sub.3).sub.2p+1 (II) wherein p is an integer of from 1 to 8, provided that at least one of R.sup.1 and R.sup.2 is the group of the formula (II).

The present invention relates to a highly oxygen-permeable heat-resistant 
material. More particularly, it relates to a highly oxygen-permeable 
heat-resistant material which is excellent in the oxygen permeability and 
heat resistance and has high hardness, a high refractive index and 
excellent transparency, dimensional stability and durability and which is 
thus suitable for use as an oxygen-enriching membrane or as an ocular lens 
material such as a contact lens material or an intraocular lens material. 
Heretofore, in order to increase the oxygen permeability of a contact lens 
material, it has been attempted to copolymerize a silicon-containing 
(meth)acrylate type monomer or a silicon-containing styrene type monomer 
having a siloxane bond in its molecule with a suitable copolymerizable 
component and to use the copolymer thereby obtained. 
However, in order to further improve the oxygen permeability of a contact 
lens material, it is required to use a large amount of the 
silicon-containing (meth)acrylate type monomer or the silicon-containing 
styrene type monomer at the time of preparing the above copolymer. 
Consequently, the resulting copolymer has had problems such that the glass 
transition temperature tends to be very low or does not substantially 
increase so that the hardness is inadequate as a contact lens material, 
and it tends to be a material inferior also in the dimensional stability. 
Under these circumstances, the present inventors have conducted extensive 
researches to develop a material which is excellent in the oxygen 
permeability and which at the same time has a high glass transition 
temperature and high hardness and is excellent in the heat resistance and 
dimensional stability, and as a result, have found that a material 
consisting essentially of a polymer obtained by using a specific stilbene 
derivative as a polymerizable component, not only is excellent in the 
above physical properties but also is excellent in the transparency and 
durability and has a high refractive index. The present invention has been 
accomplished on the basis of this discovery. 
That is, the present invention provides a highly oxygen-permeable 
heat-resistant material consisting essentially of a polymer obtained by 
polymerizing a polymerizable component containing a silicon-containing 
stilbene derivative of the formula (I): 
##STR2## 
wherein each of R.sup.1 and R.sup.2 which are independent of each other, 
is a hydrogen atom or a group of the formula (II): 
EQU --Si.sub.p O.sub.p-1 (CH.sub.3).sub.2p+1 (II) 
wherein p is an integer of from 1 to 8, provided that at least one of 
R.sup.1 and R.sup.2 is the group of the formula (II). 
Now, the present invention will be described in detail with reference to 
the preferred embodiments. 
As mentioned above, the highly oxygen-permeable heat-resistant material of 
the present invention is the one consisting essentially of a polymer 
obtained by polymerizing a polymerizable component containing a 
silicon-containing stilbene derivative of the formula (I): 
##STR3## 
wherein each of R.sup.1 and R.sup.2 which are independent of each other, 
is a hydrogen atom or a group of the formula (II): 
EQU --Si.sub.p O.sub.p-1 (CH.sub.3).sub.2p+1 (II) 
wherein p is an integer of from 1 to 8, provided that at least one of 
R.sup.1 and R.sup.2 is the group of the formula (II). 
The silicon-containing stilbene derivative of the formula (I) is a compound 
with a nature to impart excellent permeability to the resulting polymer 
and increase the glass transition temperature to improve the hardness, 
heat resistance and dimensional stability, as well as to impart excellent 
transparency, durability and a high refractive index. 
In the above formula (I), each of R.sup.1 and R.sup.2 which are independent 
of each other, is a hydrogen atom or a group of the formula (II). In the 
formula (II), when p is larger than 8, the relative amount of units 
derived from the stilbene structure in the polymer decreases, whereby it 
tends to be difficult to obtain the effect of improving the heat 
resistance, such being undesirable. 
Further, in the above formula (I), at least one of R.sup.1 and R.sup.2 is 
the group of the formula (II). It is preferred that each of R.sup.1 and 
R.sup.2 is the group of the formula (II), since the oxygen-permeability of 
the resulting polymer will thereby be effectively improved. 
When R.sup.1 and/or R.sup.2 in the formula (I) is a group of the formula 
(II), the respective position may be the o-, m- or p-position to the 
ethylene group (--HC.dbd.CH--). However, taking into consideration the 
copolymerizability with e.g. a monomer having an unsaturated double bond 
copolymerizable with the silicon-containing stilbene derivative and the 
mobility of R.sup.1 and R.sup.2 due to the steric hindrance, it is 
preferred that each of R.sup.1 and R.sup.2 is bonded at the p- or 
m-position to the ethylene group. 
Typical examples of the silicon-containing stilbene derivative include 
3-trimethylsilylstilbene, 4-trimethylsilylstilbene, 
3,3'-bis(trimethylsilyl)stilbene, 4,4'-bis(trimethylsilyl)stilbene, 
4,3'-bis(trimethylsilyl)stilbene, 3-pentamethyldisiloxanylstilbene, 
4-pentamethyldisiloxanylstilbene, 
3,3'-bis(pentamethyldisiloxanyl)stilbene, 4,4'-bis(pentamethyldisiloxanyl) 
stilbene, 3-tris(trimethylsiloxy)silylstilbene, 
4-tris(trimethylsiloxy)silylstilbene, 
3,3'-bis(tris(methylsiloxy)silyl)stilbene and 
4,4'-bis(tris(trimethylsiloxy)silyl)stilbene. These compounds may be used 
alone or in combination as a mixture of two or more of them. Among them, 
4,4'-bis(trimethylsilyl)stilbene, 3,3'-bis(trimethylsilyl)stilbene and 
4,3'-bis(trimethylsilyl)stilbene are preferred in view of the improvement 
in the oxygen permeability and heat resistance of the resulting polymer. 
The stilbene derivative has a cis-form and a transform. In the present 
invention, either form may be employed. However, from the viewpoint of the 
polymerizability with other polymerizable component, the trans-form is 
preferred. 
In the present invention, from a polymer obtained by using the above 
silicon-containing stilbene derivative as a sole polymerizable component, 
it is possible to obtain a material which is particularly excellent in the 
oxygen permeability and has a high glass transition temperature, high 
hardness and excellent heat resistance and dimensional stability. However, 
it is possible to use, in addition to such as silicon-containing stilbene 
derivative, a monomer having an unsaturated double bond, (hereinafter 
referred to as monomer (B)) copolymerizable with the silicon-containing 
stilbene derivative (hereinafter referred to as silicon-containing 
stilbene derivative (A)), as a polymerizable component. The monomer (B) 
may be used in a proper combination with the silicon-containing stilbene 
derivative (A) by adjusting its amount, depending upon the nature of the 
desired highly oxygen-permeable heat-resistant material. 
For example, in order to improve the ultraviolet absorptivity of the 
resulting highly oxygen-permeable heat-resistant material or to further 
improve the heat resistance or hardness, it is preferred to employ maleic 
anhydride or maleimide compound as the monomer (B). 
Typical examples of the maleimide compound include 
trimethylsilylmethylmaleimide, trimethylsilylethylmaleimide, 
trimethylsilylpropylmaleimide, N-tristrimethylsiloxystyrylmethylmaleimide, 
N-(3-tristrimethylsiloxysilylpropyl)maleimide, 
N-2,2,2-trifluoroethyl)maleimide, N-(2-trifluoromethyl)phenylmaleimide, 
N-(3-trifluromethyl)phenylmaleimide, N-(4-trifluromethyl)phenylmaleimide, 
N-(4-perfluoropropyl)phenylmaleimide, 
N-(4-perfluoroisopropyl)phenylmaleimide, 
N-(4-perfluorobutyl)phenylmaleimide, N-(4-perfluorooctyl)phenylmaleimide, 
N-(3,5-bis(trifluoromethyl))phenylmaleimide, 
N-(3,5-bis(trifluoromethyl))benzylmaleimide, 
N-(perfluorooctyl)phenylmaleimide, 
N-(3,5-bis(2,2,2-trifluoroethyl))phenylmaleimide, N-phenylmaleimide, 
N-chlorophenylmaleimide, N-methylphenylmaleimide, 
N-hydroxyphenylmaleimide, N-methoxyphenylmaleimide, 
N-carboxyphenylmaleimide, N-nitrophenylmaleimide, 
N-tribromophenylmaleimide, an N-alkylmaleimide such as N-methylmaleimide, 
N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide or 
N-cyclohexylmaleimide, N-naphthylmaleimide, N-laurylmaleimide, 
N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, 
N,N'-m-phenylene bismaleimide, N,N'-p-phenylene bismaleimide, 
N,N'-4,4'-diphenyl ether bismaleimide, 
N,N'-methylenebis(3-chloro-p-phenylene)bismaleimide, 
N,N'-4,4'-diphenylsulfone bismaleimide, N,N'-4,4'-dicyclohexylmethane 
bismaleimide, N,N'-.alpha.,.alpha.'-4,4'-dimethylene cyclohexane 
bismaleimide, N,N'-4,4'-diphenylcyclohexane bismaleimide, 
2-hydroxyethylmalemide, and maleimide. These maleimides may be used alone 
or in combination as a mixture of two or more of them. 
For example, in order to improve the hydrophilic nature of the resulting 
highly oxygen-permeable heat-resistant material, (meth)acrylic acid, a 
hydroxyl group-containing (meth)acrylate, a (meth)acrylamide type monomer 
or a vinyl lactam may, for example, be used as the monomer (B). 
Typical examples of the above hydroxyl group-containing (meth)acrylate 
include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 
hydroxybutyl (meth)acrylate, dihydroxypropyl (meth)acrylate, and 
diethylene glycol mono (meth)acrylate. Typical examples of the above 
(meth)acrylamide type monomer include (meth)acrylamide, N-methyl 
(meth)acrylamide, N-ethyl (meth)acrylamide, N-hydroxyethyl 
(meth)acrylamide, and N,N'-dimethyl (meth)acrylamide. A typical example of 
the above vinyl lactam may be N-vinylpyrrolidone. 
For example, in order to further improve the oxygen permeability of the 
resulting highly oxygen-permeable heat-resistant material, a 
silicon-containing (meth)acrylate, a silicon-containing styrene 
derivative, a fluorine-containing (meth)acrylate, a fluorine-containing 
styrene derivative, or a fluorine and/or silicon-containing fumarate may, 
for example, be employed. 
Typical examples of the silicon-containing (meth)acrylate include 
pentamethyldisiloxanylmethyl (meth)acrylate, pentamethyldisiloxanylpropyl 
(meth)acrylate, methylbis(trimethylsiloxy)silylpropyl (meth)acrylate, and 
tris(trimethylsiloxy)silylmethyl (meth) acrylate. Typical examples of the 
above silicon-containing styrene derivative include trimethylsilylstyrene, 
and tris(trimethylsiloxy)silylstyrene. Typical examples of the 
fluorine-containing (meth)acrylate include trifluoroethyl (meth)acrylate, 
and hexafluoroisopropyl (meth)acrylate. Typical examples of the 
fluorine-containing styrene derivative include pentafluorostyrene, 
trifluoromethylstyrene, p-vinyl benzoic acid 
2,2-trifluoro-1-(trifluoromethyl)ethyl ester, and (p-vinylphenyl)acetic 
acid 2,2,2-trifluoro-1-(trifluoromethyl)ethyl ester. Typical examples of 
the fluorine and/or silicon-containing fumarate includes 
bis(trimethylsilylpropyl)fumarate, 
bis(pentamethyldisiloxanylpropyl)fumarate, 
bis[tetramethyl(trimethylsiloxy)disiloxanylpropyl]fumarate, 
bis[trimethylbis(trimethylsiloxy)disiloxanylpropyl]fumarate, 
i-propyl(trimethylsilylpropyl)fumarate, 
siloxanyl(trimethylsilylpropyl)fumarate, 
i-propyl(pentamethyldisiloxanylpropyl)fumarate, 
cyclohexyl(pentamethyldisiloxanylpropyl)fumarate, 
i-propyl[tetramethyl(trimethylsiloxy)disiloxanylpropyl]FUMARATE, 
cyclohexyl[tetramethyl(trimethylsiloxy)disiloxanylpropyl]fumarate, 
i-propyl[trimethylbis(trimethylsiloxy)disiloxanylpropyl]fumarate, 
cyclohexyl[trimethylbis(trimethylsiloxy)disiloxanylpropyl]fumarate, and 
hexafluoroisopropyl(tristrimethylsiloxysilylpropyl)fumarate. 
Further, for example, in order to improve the mechanical strength of the 
resulting highly oxygen-permeable heat-resistant material, a styrene 
derivative which may be substituted by an alkyl group, an alkyl 
(meth)acrylate or an alkyl fumarate may, for example, be employed. 
Typical examples of the styrene derivative which may be substituted by an 
alkyl group include o-methylstyrene, m-methylstyrene, p-methylstyrene, 
trimethylstyrene, p-t-butylstyrene, and m-t-butylstyrene. Typical examples 
of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl 
(meth)acrylate, m-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl 
(meth)acrylate, i-butyl 
hexafluoroisopropyl(tristrimethylsiloxysilylpropyl)fumarate. 
Further, for example, in order to improve the mechanical strength of the 
resulting highly oxygen-permeable heat-resistant material, a styrene 
derivative which may be substituted by an alkyl group, an alkyl 
(meth)acrylate or an alkyl fumarate may, for example, be employed. 
Typical examples of the styrene derivative which may be substituted by an 
alkyl group include o-methylstyrene, m-methylstyrene, p-methylstyrene, 
trimethylstyrene, p-t-butylstyrene, and m-t-butylstyrene. Typical examples 
of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl 
(meth)acrylate, m-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl 
(meth)acrylate, i-butyl (meth)acrylate, sec-butyl (meth)acrylate, and 
t-butyl (meth)acrylate. Typical examples of the alkyl fumarate include 
di-i-propyl fumarate, di-t-butyl fumarate, i-propyl(t-butyl)fumarate, 
dicyclohexyl fumarate, and cyclohexyl(t-butyl)fumarate. 
The above monomer (B) may be used as a single compound or a mixture of two 
or more compounds. Its amount may be optionally determined depending upon 
the particular purpose of the resulting highly oxygen-permeable 
heat-resistant material or the type of the monomer (B) to be used. 
However, in order to obtain a good polymer or in order to further improve 
the oxygen permeability or the heat resistance of the polymer, it is 
usually preferred to use it in an amount of at least 90 parts by mol, more 
preferably at least 95 parts by mol, per 100 parts by mol of the 
silicon-containing stilbene derivative (A). Further, in order to 
sufficiently obtain the effects by the silicon-containing stilbene 
derivative (A), the amount of the monomer (B) is usually at most 1,000 
parts by mol, more preferably at most 900 parts by mol, per 100 parts by 
mol of the silicon-containing stilbene derivative (A). Further, in the 
present invention, a usual crosslinking agent may be employed as an 
optional component to obtain a highly oxygen-permeable heat-resistant 
material. 
Such a a crosslinking agent is a component which is capable of forming a 
three dimensional crosslinking structure in the highly oxygen-permeable 
heat-resistant material such as an ocular lens material to make it a 
material which is tough and has improved mechanical strength and hardness 
and which, at the same time, is transparent and free from turbidity or 
strain and rich in the optical property. Further, it provides other 
crosslinking effects such as the effects of improving durability such as 
chemical resistance, heat resistance or dimensional stability and of 
minimizing elution of substances. 
Typical examples of the crosslinking agent include 4-vinylbenzyl 
(meth)acrylate, 3-vinybenzyl (meth)acrylate, ethylene glycol 
di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol 
di (meth)acrylate, propylene glycol di (meth)acrylate, dipropylene glycol 
di(meth)acrylate, vinyl (meth)acrylate, trimethylolpropane 
tri(meth)acrylate, (meth)acryloyloxyethyl (meth)acrylate, divinylbenzene, 
diallyl phthalate, diallyl adipate, .alpha.-methylene-N-vinylpyrrolidone, 
2,2-bis(4-(meth)acryloyloxyphenyl)hexafluoropropane, 
2,2-bis(3-(meth)acryloyloxyphenyl)hexafluoropropane, 
2,2-bis(2-(meth)acryloyloxyphenyl)hexafluoropropane, 
2,2-bis(4-meth)acryloyloxyphenyl)propane, 
2,2-bis(3-meth)acryloyloxyphenyl)propane, 
2,2-bis(meth)acryloyloxyphenyl)propane, 
1,4-bis(2-meth)acryloyloxyhexafluoroisopropyl)benzene, 
1,3-bis(meth)acryloyloxyhexafluoroisopropyl)benzene, 
1,2-bis(2-(meth)acryloyloxyhexafluoroisopropyl)benzene, 
1,4-bis(2-(meth)acryloyloxyisopropyl)benzene, 
1,3-bis(2-meth)acryloyloxyisopropyl)benzene, and 
1,2-bis(2-meth)acryloyloxyisopropyl)benzene. These crosslinking agents may 
be used alone or in combination as a mixture of two or more of them. 
The amount of the crosslinking agent is usually preferably at least 1 part 
by weight, more preferably at least 5 parts by weight, per 100 parts by 
weight of the total amount to the polymerizable components, in order to 
sufficiently improve the mechanical strength of the highly 
oxygen-permeable heat-resistant material. Further, it is usually 
preferably at most 15 parts by weight, more preferably at most 10 parts by 
weight, per 100 parts by weight of the total amount of the polymerizable 
components, in order to prevent the possibility of weakening against a 
stress such as an impact. 
As a method for producing the highly oxygen-permeable heat-resistant 
material of the present invention, there may, for example, be mentioned a 
method wherein a radical polymerization initiator such as 
azobisisobutyronitrile, azobisdimethylvaleronitrile, benzoyl peroxide, 
t-butyl hydroperoxide or cumene peroxide is added to the polymerizable 
component obtained by mixing the above silicon-containing stilbene 
derivative (A) and, if necessary, the monomer (B) and the crosslinking 
agent, usually in an amount of from 0.01 to 1 part by weight, per 100 
parts by weight of the total amount of the polymerizable component, 
followed by polymerization in a usual manner such as heating, to obtain a 
polymer, or a method in which a photopolymerization initiator such as 
benzoyl, benzophenone or benzil, is added to the polymerizable component 
in an amount of from 0.01 to 1 part by weight, per 100 parts by weight of 
the total amount of the polymerizable component, followed by 
polymerization by irradiation with light rays with a wavelength 
corresponding to the absorption band of the photopolymerization initiator, 
to obtain a polymer. 
Preparation of the above polymer can be carried out by e.g. bulk 
polymerization, or solution polymerization using a solvent such as 
chloroform, acetone or benzene. In a case where the silicon-containing 
stilbene derivative (A) or the maleimide compound as an example of the 
monomer (B) are solid and have no good compatibility with other 
polymerizable components, it is preferred to employ a solution 
polymerization method. 
A method for processing the polymer thus obtained into a highly 
oxygen-permeable heat-resistant material of the present invention having a 
desired shape, is not particularly limited. For example, it may be a 
method wherein the polymer is dissolved in a solvent such as chloroform, 
acetone, benzene or tetrahydrofuran, and then the resulting solution of 
the polymer is cast, a method wherein compression forming is applied to 
the polymer, or a method wherein the polymer or the polymer solution is 
subjected to injection molding. 
Further, the above polymer may be dissolved in a monomer component, 
followed by polymerization to form a polymer alloy having two or more 
polymers mixed, and the obtained polymer alloy may be processed into a 
highly oxygen-permeable heat-resistant material having a desired shape by 
the above-mentioned method. 
The highly oxygen-permeable heat-resistant material of the present 
invention has a feature that it is particularly excellent in the oxygen 
permeability and has excellent transparency and a high refractive index. 
Accordingly, it is useful as an ocular lens material. When such a highly 
oxygen-permeable heat-resistant material is used as an ocular lens 
material such as a contact lens material or an intraocular lens material, 
the method for preparing an ocular lens such as a contact lens from the 
ocular lens material, may, for example, be a method wherein mechanical 
processing such as cutting and polishing, is applied to the obtained 
polymer to obtain a lens having a desired shape. As another method, a 
method may be mentioned wherein a mold having a desired shape is prepared, 
and the respective components such as the above mentioned polymerization 
components, may directly be polymerized in such a mold to obtain a shaped 
product. In such a case, mechanical finishing treatment may be applied to 
the resulting contact lens, as the case requires. 
As described in the foregoing, the highly oxygen-permeable heat-resistant 
material of the present invention is the one consisting essentially of a 
polymer obtained by polymerizing a polymerizable component containing a 
silicon-containing stilbene derivative of the formula (I). Accordingly, by 
virtue of such a silicon-containing stilbene derivative, the material is 
excellent particularly in the oxygen permeability and heat resistance and 
has high hardness, a high refractive index and excellent transparency, 
dimensional stability and durability, and it is suitable for use as an 
oxygen enriching membrane or as an ocular lens material.

Now, the highly oxygen-permeable heat-resistant material of the present 
invention will be described in further detail with reference to Examples. 
However, it should be understood that the present invention is by no means 
restricted to such specific Examples. 
PREATION EXAMPLE 1 
Preparation of trans-4,4'-bis(trimethylsilyl)stilbene 
Into a four-necked round bottom flask having a capacity of 2 l and equipped 
with a stirring motor, a dropping funnel, a Dimroth condenser and a 
thermometer, 36.47 g (1.5 mols) of magnesium was introduced, and a 
solution having 235.91 g (1.0 mol) of 1,4-dibromobenzene dissolved in 750 
ml of diethyl ether, was slowly dropwise added to the magnesium in a 
nitrogen atmosphere. After completion of the dropwise addition, the 
four-necked round bottom flask having a capacity of 2 l, was heated to 
about 40.degree. C., and the reaction was further continued for one hour. 
Then, excess magnesium was removed, and a solution having 149.3 (1.37 mols) 
of trimethylchlorosilane dissolved in 150 ml of diethyl ether, was 
dropwise added to the four-necked round bottom flask having a capacity of 
2 l. After completion of the dropwise addition, stirring was continued at 
room temperature for 16 hours. 
The precipitated salt was removed by filtration, and 200 ml of distilled 
water was slowly dropwise added to the filtrate under cooling with ice to 
deactivate an unreacted Grignard reagent and trimethylchlorosilane. Then, 
the organic layer was taken out and washed three times with 500 ml of 
distilled water. The organic layer was dried over anhydrous sodium 
sulfate, and the solvent was distilled off. The obtained liquid was 
purified by distillation to obtain 43.24 g of 4-trimethylsilylbromobenzene 
(boiling point: 118.6-126.0.degree. C./20 mmHg). 
Then, into a four-necked round bottom flask having a capacity of 200 ml and 
equipped with a stirring motor, a dropping funnel, a Dimroth condenser and 
a thermometer, 4.59 g (0.189 mol) of magnesium was introduced, and a 
solution having 43.24 g (0.189 mol) of the obtained 
4-trimethylsilylbromobenzene dissolved in 90 ml of diethyl ether, was 
slowly dropwise added to the magnesium in a nitrogen atmosphere. After 
completion of the dropwise addition, the four-necked round bottom flask 
having a capacity of 200 ml, was heated to about 40.degree. C., and the 
reaction was further continued for one hour. Then, a solution having 7.27 
g (0.075 mol) of trans-1,2-dichloroethylene dissolved in 10 ml of diethyl 
ether, was dropwise added to the four-necked round bottom flask having a 
capacity of 200 ml, and stirring was continued at room temperature for 16 
hours. 
The precipitated salt was removed by filtration, and the filtrate was 
washed three times with 200 ml of distilled water. Then, the taken out 
organic layer was dried over anhydrous sodium sulfate, and the solvent was 
distilled off to obtain 35.72 g of slightly yellow crystals (yield: 
22.1%). 
The obtained slightly yellow crystals were dissolved in carbon 
tetrachloride, and the 1H-NMR spectrum (60 MHz) was measured by means of 
JNM-PMX 60, manufactured by JEOL LTD. As a result, a signal attributable 
to --Si(CH.sub.3).sub.3 was observed in the vicinity of 0.26 ppm, a signal 
attributable to --HC.dbd.CH-- was observed in the vicinity of 7.07 ppm, 
and a signal attributable to an aromatic nucleus hydrogen was observed in 
the vicinity of 7.45 ppm. 
Further, the mass spectrum was measured by means of GC-MS (5809 II gas 
chromatograph+5971A mass detector), manufactured by Hewlett-Packard Co. As 
a result, it was observed that a molecular ion peak was present at 324. 
Furthermore, the infrared absorption spectrum was measured by a KBr tablet 
method by means of FT/IR-8300, manufactured by Nippon Bunko Kogyo K.K. As 
a result, an absorption attributable to C--H of an aromatic nucleus was 
observed in the vicinity of 3080 cm.sup.-1 and 3100 cm.sup.-1, an 
absorption attributable to C--H of an ethylene group was observed in the 
vicinity of 2900 cm.sup.-1 and 2950 cm.sup.-1, and an absorption 
attributable to Si--C was observed in the vicinity of 840 cm.sup.-1. 
From these results, the obtained slightly yellow crystals were confirmed to 
be trans-4,4'-bis(trimethylsilyl)stilbene of the formula: 
##STR4## 
EXAMPLE 1 
0.6492 g (2 mmol) of trans-4,4'-bis(trimethylsilyl)stilbene obtained in 
Preparation Example 1, 0.363 g (2 mmol) of N-phenylmaleimide and 0.003 g 
of 2,2'-azobis(2,4-dimethylvaleronitrile) as a polymerization initiator 
were dissolved in 3 ml of chloroform, and the solution was introduced into 
a glass test tube, sealed and polymerized in a constant temperature water 
tank of 35.degree. C. for 64 hours. Then, the solution containing the 
formed polymer was dropwise added to a large amount of methanol to 
precipitate the polymer, which was purified by reprecipitation. The 
obtained purified polymer was dissolved in chloroform and cast to obtain a 
test sample film having a thickness of about 0.1 mm. Such a test sample 
film was visually inspected, whereby it was colorless and excellent in the 
transparency. 
Using the obtained test sample film, the oxygen permeation coefficient and 
the glass transition temperature were measured in accordance with the 
following methods. As a result, the oxygen permeation coefficient was 
79.3'10.sup.-11 (cm.sup.2 /sec).(mlO.sub.2 /(ml.times.mmHg)), and the 
glass transition temperature was 360.degree. C. 
(a) Oxygen permeation coefficient 
Using a Seikaken Model film oxygen permeation meter manufactured by Rika 
Seiki Kogyo K.K., the oxygen permeation coefficient was measured in a 
physiological sodium chloride aqueous solution. 
(b) Glass transition temperature 
Using a dynamic visco elasticity measuring apparatus RSA II, manufactured 
by Rheometrics Co. Ltd., the temperature dispersion (frequency: 1 Hz) was 
measured in a tensile mode, whereby the temperature at which the storage 
modulus of elasticity started to decrease was taken as the glass 
transition temperature. 
EXAMPLE 2 
A test sample film having a thickness of about 0.1 mm was prepared in the 
same manner as in Example 1 except that in Example 1, 0.3783 g (2 mmol) of 
N-p-hydroxyphenylmaleimide was used instead of 0.363 g (2 mmol) of 
N-phenylmaleimide, and the amount of chloroform was changed from 3 ml to 
3.5 ml. Such a test sample film was visually inspected, whereby it was 
colorless and excellent in the transparency. 
Using the obtained test sample film, the oxygen permeation coefficient was 
measured in the same manner as in Example 1, whereby it was 
60.1.times.10.sup.-11 (cm.sup.2 /sec).(mlO.sub.2 /(ml.times.mmHg)). 
Comparative Example 1 
1.7317 g (10 mmol) of 4-trimethylsilylstyrene, 1.7634 g (10 mmol) of 
N-phenylmaleimide and 0.015 g of 2,2'-azobis(2,4-dimethylvaleronitrile) as 
a polymerization initiator were dissolved in 15 ml of acetone, and the 
solution was introduced into a glass test tube, deaerated, then sealed and 
polymerized in a constant temperature water tank at 35.degree. C. for 64 
hours. Then, the solution containing the formed polymer was dropwise added 
to a large amount of diethyl ether to precipitate the polymer, which was 
purified by reprecipitation. The obtained purified polymer was dissolved 
in chloroform and cast to obtain a test sample film having a thickness of 
about 0.1 mm. Such a test sample film was visually inspected, whereby it 
had sufficient transparency as an ocular lens material. 
Using the obtained test sample film, the oxygen permeation coefficient and 
the glass transition temperature were measured in the same manner as in 
Example 1. As a result, the oxygen permeation coefficient was 
30.8.times.10.sup.-11 (cm.sup.2 /sec).(mlO.sub.2 /(ml.times.mmHg)), and 
the glass transition temperature was 214.degree. C. 
From the above results, it is evident that the films of Examples 1 and 2 
obtained by using a silicon-containing stilbene derivative as a 
polymerizable component, have oxygen permeation coefficients remarkably 
larger by twice or more than twice than the film of Comparative Example 1 
obtained by using a conventional silicon-containing styrene type monomer 
as a polymerizable component, and the film of Example 1 has a glass 
transition temperature higher by at least 100.degree. C. than the film of 
Comparative Example 1. This indicates that the films of the Examples of 
the present invention are far superior in the oxygen permeability and have 
high hardness and excellent heat-resistance. 
The highly oxygen-permeable heat-resistant material of the present 
invention is the one obtained by using a specific silicon-containing 
stilbene derivative as a polymerizable component, and accordingly it is 
particularly excellent in the oxygen permeability and has a high glass 
transition temperature, excellent heat resistance and high hardness, and 
it is further excellent in the transparency, dimensional stability and 
durability and has a high refractive index. As such, it is suitable for 
use as an oxygen enriching membrane or as an ocular lens material such as 
a contact lens material or an intraocular lens material.