The present invention relates to a polymerizable composition comprising an alicyclic isocyanate compound.
TECHNICAL FIELD [0001]
The present invention relates to a polyurethane lens having good optical properties and resin strength.
BACKGROUND ART [0002]
Plastic lenses are lighter, less in cracking and tintable in comparison with inorganic lenses. Therefore, in recent years, the application of plastic lenses to optical elements such as spectacle lenses and camera lenses has increased rapidly.
For this reason, the resin for plastic 'lenses having improved performance is desired. Further, the resin for plastic lenses having higher refractive index, higher Abbe number, lower specific gravity and higher heat resistance is desired. Until now, the resin material for various lenses has been developed. [0003]
Among them as to the representative examples, the polythiourethane resin having high refractive index by increasing a sulfur contents in thiol, which is used as

polythiourethane, is developed (See Patent Documents 1
and 2). Among them, the polyurethane resin using
alicyclic isocyanate compound represented by the
formula (1) and/or the formula (2) (it will be
described later) provides plastic lenses having
incredibly excellent balance of high Abbe number, high
heat resistance (See Patent Document 3).
[0004]
However, although the above polythiourethane resin
is provided with improved high Abbe number, heat
resistance, as well as some extent of improved
refractive index, higher refractive index is desired.
Further, the polythiourethane resin using alicyclic
isocyanate compound represented by the formula (1)
and/or (2) and the polythiol represented by following
formula:
[0005]
(Figure Removed)
[0006]
gives high refractive index, Abbe number, and heat
resistance (See Patent Document 4).
[0007]
In the above polythiourethane resin, it has high
refractive index, high Abbe number, and high heat
resistance. However, if the resin has higher
refractive index, the specific gravity tends to be
higher and the strength of the resin is insufficient,
and during processing of the resin, problem of
occurring of cracking or breaking of the resin arises.
In this regard, it has a problem that the yield is poor
Further, if heat resistance is lower, the crack is
occurred on using after coating treatment. Further, if
heat resistance is higher, resin strength tends to be
poorer. For these reasons, the resins having a given
refractive index, heat resistance, strength, and
specific gravity in balanced manner are demanded.
[0008]
Japanese Laid-Open Patent Document 1 Publication
HEI2-270859
Patent Document 2
HEI7-252207
Patent Document 3
HEI3-124722
Patent Document 4
HEI9-110956
Japanese Laid-Open Publication
Japanese Laid-Open Publication
Japanese Laid-Open Publication
DISCLOSURE OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0009]
The problem is that resin strength of the
polythiourethane resin as obtained above is still
insufficient. Therefore it is an object of the
invention to provide a polythiourethane resin having
high refractive index, high Abbe number, high heat
resistance, low specific gravity and sufficient
strength.
MEANS FOR SOLVING THE PROBLEMS
[0010]
In order to solve the above problems, the present
inventors have proceeded with an extensive
investigation. As a result, the inventors have found
that the polyurethane lenses obtained by curing a
polymerizable composition comprising an alicyclic
isocyanate compound represented by the following the
formula (1) and/or (2),
(a) at least one compound of the polythiol compound
having at least two thiol groups in one molecule and/or
the polythiol compound having at least two thiol groups
and at least one (poly)sulfide bond other than the
thiol group in one molecule, and
(b) at least one compound of polyhydroxy compound
having at least two hydroxy groups in one molecule
and/or (poly)hydroxy(poly)mercapto compound having at
least one hydroxy group and at least one thiol group in
one molecule has a desired physical properties and
excellent tintability. Thus the present invention has
been achieved.
[0011]
Namely, the present invention relates to the following
[I] to [10] :
[1] A polymerizable composition comprising an
alicyclic isocyanate compound represented by the
formula (1) and/or (2):
[0012]
(Figure Removed)
(In the formula (1), n represents an integer of 0 to
[0013]
[0014]
(a) at least one compound of a polythiol compound
having at least two thiol groups in one molecule and/or
a polythiol compound having at least two thiol groups
and at least one (poly)sulfide bond other than the
6
thiol group in one molecule, and
(b) at least one compound of a polyhydroxy compound
having at least two hydroxy groups in one molecule
and/or a (poly)hydroxy(poly)mercapto compound having at
least one hydroxy group and at least one thiol group in
one molecule.
[2] A polymerizable composition comprising an
alicyclic isocyanate compound represented by the
formula (3):
(Figure Removed)
(a) at least one compound of a polythiol compound
having at least two thiol groups in one molecule and/or
the polythiol compound having at least two thiol groups
and at least one (poly)sulfide bond other than the
thiol group in one molecule, and
(b) at least one compound of a polyhydroxy compound
having at least two hydroxy groups in one molecule
and/or a (poly)hydroxy(poly)mercapto compound having at
least one hydroxy group and at least one thiol group in
one molecule.
[3] The polymerizable composition according to [1] or
[2], wherein the polythiol compound having at least two
thiol groups in one molecule and/or the polythiol
compound having at least two thiol groups and at least
one (poly)sulfide bond other than the thiol group in
one molecule is at least one polythiol compound
selected from
4-mercaptomethyl-l,8-dimercapto-3,6-dithiaoctane,
1,1,3, 3-tetrakis(mercaptomethyl)-2-thiapropane,
2,5-bismercaptomethyl-l,4-dithiane,
bis(mercaptoethyl)sulfide,
1,1,3,3-tetrakis(mercaptomethylthio)propane,
2-{2,2-bis(mercaptomethylthio)ethyl}-!,3-dithiethane,
and
4,6-bis mercaptomethylthio-1,3-dithiane.
[4] The polymerizable composition according to any
one of the [1], [2], and [3], wherein, if the mole
number of hydroxy group and thiol group of the
polyhydroxy compound having at least two hydroxy groups
in one molecule and/or the (poly)hydroxy(poly)mercapto
compound having at least one hydroxy group and at least
one thiol group in one molecule, are A and B
respectively, and the mole number of the thiol group of
the polythiol compound having at least two thiol groups
and/or the polythiol compound having at least two thiol
groups and at least one (poly)sulfide bond other than
the thiol group in one molecule, is C, A/(A+B+C) is
from 0.1 to 40%.
[5] The polymerizable composition according to any
one of the [1] to [4], wherein the polyhydroxy compound
having at least two hydroxy groups in one molecule
and/or the (poly)hydroxy(poly)raercapto compound having
at least one hydroxy group and at least one thiol group
in one molecule is at least one (poly)hydroxy group
containing compound selected from (poly)hydroxy(poly)
mercapto compound, 2-mercaptoethanol, 3-mercapto-l,2-
propanediol, pyrogallol, ethylene glycol,
polycaprolactondiol, and polyalkyleneoxidepolyol
represented by the formula(4):
(Figure Removed)
(wherein, m represents an integer.)
[6] The polymerizable composition according to [1] or
[4], wherein an alicyclic isocyanate compound is
isocyanate compound described in the formula (1),
the polythiol compound having at least two thiol groups
in one molecule and/or the polythiol compound having at
least two thiol groups and at least one (poly)sulfide
bond other than the thiol group in one molecule is 4-
mercaptomethyl-1,8-dimercapto-3f6-dithiaoctane, or 4,8-
dimercapto methyl-1,ll-mercapto-3,6,9-trithiaundecane ,
the polyhydroxy compound having at least two hydroxy
groups in one molecule and/or the
(poly)hydroxy(poly)mercapto compound having at least
one hydroxy group and at least one thiol group in one
molecule is 2-mercaptoethanol.
[7] A process for producing a resin by curing the
polymerizable composition according to any one of [1]
to [6].
[8] A resin obtained by curing the polymerizable
composition according to any one of [1] to [6].
[9] An optical element comprising the resin according
to [8].
[10] A lens comprising the optical element according
to [9].
EFFECT OF THE INVENTION
[0019]
According to the present invention, a
polyisocyanate compound suitably used as a transparent
resin material and a polymerizable composition
comprising the compound are discovered. Accordingly, a
polythiourethane resin material obtained by curing the
compounds may meet a requirement of refractive index,
Abbe number, heat resistance and resin strength, and
have excellent tintability.
BEST MODE FOR CARRYING OUT THE INVENTION
[0020]
The process for producing a polyurethane lens of
the present invention and polyurethane lens obtained by
the process solve the above problems, and it is
provided a polyurethane lens which meets a requirement
of refractive index of resin, Abbe number, heat
resistance, and strength of resin successfully, and has
excellent tintability.
[0021]
The polyurethane lens of the present invention can
be produced by mixing the alicyclic isocyanate compound
represented by the formula (1) and/or the formula (2),
with
(a) at least one compound of the polythiol compound
having at least two thiol groups in one molecule and/or
the polythiol compound having at least two thiol groups
in one molecule and at least one (poly)sulfide bond
other than the thiol group in one molecule, and
(b) at least one compound of the polyhydroxy compound
having at least two hydroxy groups in one molecule
and/or the (poly)hydroxy(poly)mercapto compound having
at least one hydroxy group and at least one thiol group
in one molecule, and heat curing the mixture.
[0022]
The alicyclic isocyanate compounds of the present
invention include the alicyclic isocyanate compound
represented by the formula (1) such as 2,5-
bis (isocyanato)bicyclo-[2.2.1]-heptane, 2,6-
bis(isocyanato)bicyclo-[2.2.1]-heptane,
2,5-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane,
2,6-bis(isocyanatomethyl)bicyclo-[2.2.1]-heptane,
2,5-bis(isocyanatoethyl)bicyclo-[2.2.1]-heptane, and
2, 6-bis(isocyanatoethyl)bicyclo-[2.2.1]-heptane, but
are not limited thereto.
[0023]
The alicyclic isocyanate compounds represented by
the formula (2) include 1,4-
bis(isocyanatomethyl)cyclohexane,
1,3-bis(isocyanatomethyl)cyclohexane, and
1,2-bis(isocyanatomethyl)cyclohexane, but are not
limited thereto.
[0024]
The polythiol compounds having at least two thiol
groups in one molecule and/or the polythiol compound
having at least two thiol groups and at least one
(poly)sulfide bond other than the thiol group in one
molecule according to the present invention include
aliphatic polythiol compounds such as methanedithiol,
1,2-ethanedithiol, 1,1-propanedithiol, 1,2-
propanedithiol, 1,3-propanedithiol, 2,2-propanedithiol,
1,6-hexanedithiol, 1,2,3-propanetrithiol, 1,1-
cyclohexanedithiol, 1,2-cyclohexanedithiol, 2,2-
dimethylpropane-1,3-dithiol, 3,4-dimethoxybutane-l,2-
dithiol, 2-methylcyclohexane-2,3-dithiol, 1,1-
bis(mercaptomethyl)cyclohexane, 1, 2-
dimercaptopropylmethylether, 2,3-
dimercaptopropylmethylether, 2,2-bis(mercaptomethyl)-
1, 3-propanedithiol, bis(2-mercaptoethyl)ether,
tetrakis(mercaptomethyl)methane, or the like;
[0025]
aliphatic polythiol compounds containing ester bond
such as (2-mercaptoethylester) 2,3-dimercaptosuccinate,
bis(2-mercaptoethylester) thiomalate, 2,3-dimercapto-lpropanol(
2-mercaptoacetate), 2,3-dimercapto-lpropanol(
3-mercaptopropionate), 3-mercapto-l,2-
propanediol di(2-mercaptoacetate), 3-mercapto-l,2-
propanediol di(3-mercaptopropionate), diethylene glycol
bis(2-mercaptoacetate), diethylene glycol bis (3-
mercaptopropionate), ethylene glycol bis (2-
mercaptoacetate), ethylene glycol bis (3-
mercaptopropionate), trimethylolpropane tris (2-
mercaptoacetate), trimethylolpropane tris (3-
mercaptopropionate), trimethylolethane tris (2-
mercaptoacetate), trimethylolethane tris(3-
mercaptopropionate), pentaerythritol tetrakis(2-
mercaptoacetate), pentaerythritol tetrakis (3-
mercaptopropionate), glycerine tris(2-mercaptoacetate),
glycerine tris(3-mercaptopropionate), 1,4-
cyclohexanediol bis(2-mercaptoacetate) and 1,4-
cyclohexanediol bis(3-mercaptopropionate), and halogen
substituted compound thereof such as chloro substituted
compound, bromo substituted compound, or the like;
[0026]
a polythiol compound comprising benzene ring such as
1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-
dimercaptobenzene, 1,2-bis(mercaptomethyl)benzene, 1,3-
bis(mercaptomethyl)benzene, 1,4-
bis(mercaptomethyl)benzene, 1,2-
bis(mercaptoethyl)benzene, 1,3-
bis(mercaptoethyl)benzene, 1,4-
bis(mercaptoethyl)benzene,
1,2-bis(mercaptomethyleneoxy)benzene,
1,3-bis(mercaptomethyleneoxy)benzene,
1,4-bis(mercaptomethyleneoxy)benzene,
1,2-bis(mercaptoethyleneoxy)benzene,
1,3-bis(mercaptoethyleneoxy)benzene,
1,4-bis(mercaptoethyleneoxy)benzene, 1,2,3-
trimercaptobenzene, 1,2,4-tri mercaptobenzene, 1,3, 5-
trimercaptobenzene, 1,2,3-tris(mercaptomethyl)benzene,
1,2,4-tris(mercaptomethyl)benzene, 1,3,5-
tris(mercaptomethyl)benzene,
1,2,3-tris(mercaptoethyl)benzene, 1,2,4-
tris (mercaptoethyl)benzene, 1,3,5-
tris(mercaptoethyl)benzene,
1,2,3-tris(mercaptomethyleneoxy)benzene,
1,2,4-tris(mercaptomethyleneoxy)benzene,
1,3,5-tris(mercaptomethyleneoxy)benzene,
1,2,3-tris(mercaptoethyleneoxy)benzene,
1,2,4-tris(mercaptoethyleneoxy)benzene,
1,3,5-tris(mercaptoethyleneoxy)benzene, 2, 5-
toluenedithiol, 3,4-toluenedithiol, l,3-di(pmethoxyphenyl)
propane-2,2-dithiol, 1,3-diphenylpropane-
2,2-dithiol, phenylmethane-1,1-dithiol, 2,4-di(pmercaptophenyl)
pentane, 1,4-naphthalenedithiol,
1,5-naphthalenedithiol, 2,6-naphthalenedithiol,
2,7-naphthalenedithiol, 2,4-dimethylbenzene-l,3-dithiol,
4,5-dimethylbenzene-l,3-dithiol, 9,10-
anthracenedimethanethiol, 1,2,3,4-tetramercaptobenzene,
1,2,3,5-tetramercaptobenzene, 1,2,4,5-
tetramercaptobenzene,
1, 2, 3, 4-tetrakis(mercaptomethyl)benzene,
1, 2, 3, 5-tetrakis(mercaptomethyl)benzene,
1,2, 4, 5-tetrakis(mercaptomethyl)benzene,
1, 2,3,4-tetrakis(mercaptoethyl)benzene,
1, 2, 3,5-tetrakis(mercaptoethyl)benzene,
1,2,4,5-tetrakis(mercaptoethyl)benzene,
1, 2,3,4-tetrakis(mercaptomethyleneoxy)benzene,
1,2,3,5-tetrakis(mercaptomethyleneoxy)benzene,
1,2,4,5-tetrakis(mercaptomethyleneoxy)benzene,
1,2,3,4-tetrakis(mercaptoethyleneoxy)benzene,
1,2,3,5-tetrakis(mercaptoethyleneoxy)benzene,
1,2,4,5-tetrakis(mercaptoethyleneoxy)benzene,
2,2'-dimercaptobiphenyl, 4,4' -dimercaptobiphenyl,
4,4' -dimercaptobibenzyl, or the like;
[0027]
halogen substituted aromatic polythiol compounds such
as chloro substituted compounds, bromo substituted
compounds, or the like such as 2,5-dichlorobenzene-l,3-
dithiol, 1,3-di(p-chlorophenyl)propane-2,2-dithiol,
3,4,5-tribromo-l,2-dimercaptobenzene, 2,3,4,6-
tetrachlor-1,5-bis(mercaptomethyl)benzene; and
polythiol compounds containing heterocyclic ring such
as 2-methylamino-4,6-dithiol-sym-triazine , 2-
ethylamino-4,6-dithiol-sym-triazine, 2-amino-4,6-
dithiol-sym-triazine, 2-morpholino-4,6-dithiol-symtriazine,
2-cyclohexylamino-4,6-dithiol-sym-triazine,
2-methoxy-4,6-dithiol-sym-triazine, 2-phenoxy-4,6-
dithiol-sym-triazine, 2-thiobenzeneoxy-4,6-dithiol-symtriazine,
2-thiobutyloxy-4,6-dithiol-sym-triazine, or
the like and halogen substituted compound thereof such
as chloro substituted compound, bromo substituted
compound, or the like, but are not limited thereto.
[0028]
The (poly)thiol compounds having at least two
thiol groups in one molecule and at least one
(poly)sulfide bond other than the thiol group in one
molecule include aliphatic polythiol compounds, such as
bis(mercaptomethyl)sulfide,
bis(mercaptomethyl)disulfide, bis(mercaptoethyl)sulfide,
bis (mercaptoethyl)disulfide, bis(mercaptopropyl)sulfide
bis(mercaptomethylthio)methane, bis(2-
mercaptoethylthio)methane, bis(3-
mercaptopropylthio)methane,
16
1,2-bis(mercaptomethylthio)ethane,
1,2-bis(2-mercaptoethylthio)ethane,
1,2-bis(3-mercaptopropylthio)ethane,
1,3-bis(mercaptomethylthio)propane,
1,3-bis(2-mercaptoethylthio)propane,
1,3-bis(3-mercaptopropylthio)propane,
1,2,3-tris(mercaptomethylthio)propane,
1,2,3-tris(2-mercaptoethylthio)propane,
1,2,3-tris(3-mercaptopropylthio)propane,
1,2-bis[(2-mercaptoethyl)thio]-3-mercaptopropane,
5,7-dimercaptomethyl-l,1l-mercapto-3,6,9-
trithiaundecane,
tetrakis(mercaptomethylthiomethyl)methane,
tetrakis(2-mercaptoethylthiomethyl)methane,
tetrakis(3-mercaptopropylthiomethyl)methane,
bis(2,3-dimercaptopropyl)sulfide, 2,5-dimercapto-l,4-
dithian, 2,5-dimercaptomethyl-2,5-dimethyl-l,4-dithian,
or the like, and thioglycolic acid ester and
mercaptopropionic acid ester thereof;
[0029]
hydroxymethylsulfide bis(2-mercaptoacetate),
hydroxymethylsulfide bis(3-mercaptopropionate),
hydroxyethylsulfide bis(2-mercaptoacetate),
hydroxyethylsulfide bis(3-mercaptopropionate),
hydroxypropylsulfide bis(2-mercaptoacetate),
hydroxypropylsulfide bis(3-mercaptopropionate),
hydroxymethyldisulfide bis(2-mercaptoacetate),
hydroxymethyldisulfide bis(3-mercaptopropionate),
hydroxyethyldisulfide bis(2-mercaptoacetate) ,
hydroxyethyldisulfide bis(3-mercaptopropinate),
hydroxypropyldisulfide bis(2-mercaptoacetate),
hydroxypropyldisulfide bis(3-mercaptopropinate),
2-mercaptoethylether bis(2-mercaptoacetate),
2-mercaptoethylether bis(3-mercaptopropionate), and
1,4-dithiane-2,5-diol bis(3-mercaptopropionate);
[0030]
aliphatic polythiol such as
bis(2-mercaptoethylester) thiodiglycolate,
bis(2-mercaptoethylester) thiodipropionate,
bis(2-mercaptoethylester) 4,4-thiodibutyrate,
bis(2-mercaptoethylester) dithiodiglycolate,
bis(2-mercaptoethylester) dithiodipropionate,
bis(2-mercaptoethylester) 4,4-dithiodibutyrate,
bis(2,3-dimercaptopropylester) thiodiglycolate,
bis(2,3-dimercaptopropylester) thiodipropionate,
bis(2,3-dimercaptopropylester) dithiodiglycolate,
bis(2,3-dimercaptopropylester) thiodipropionate,
bis(2,3-dimercaptopropylester) dithiodipropionate, or
the like;
heterocyclic compound such as 3,4-thiophenedithiol,
bismuthiol, or the like;
[0031]
1,1,3,3-tetrakis(mercaptomethylthio)propane, 1,1,2,2-
tetrakis(mercaptomethylthio)ethane, 4,6-
bis(mercaptomethylthio)-1,3-dithiacyclohexane, 1,1,5,5-
tetrakis(mercaptomethylthio)-3-thiapentane, 1,1,6,6-
tetrakis(mercaptomethylthio)-3,4-dithiahexane, 2,2-
bis(mercaptomethylthio)ethanethiol, 2-(4,5-dimercapto-
2-thiapentyl)-1,3-dithiacyclopentane, 2,5-bis (4,4-
bis(mercaptomethylthio)-2-thiabutyl)-1,4-dithian, 2,2-
bis(mercaptomethylthio)-1,3-propanedithiol, 3-
mercaptomethylthio-1,7-dimercapto-2,6-dithiaheptane,
3,6-bis(mercaptomethylthio)-1,9-dimercapto-2,5,8-
trithianonane, 3-mercaptomethylthio-l,6-dimercapto-2,5-
dithiahexane, 2-(2,2-bis(mercaptodimethylthio)ethyl)-
1,3-dithiethane, 1,1,9,9-tetrakis(mercaptomethylthio)-
5-(3,3-bis(mercaptomethylthio)-1-thiapropyl)3,7-
dithianonane, tris(2,2-
bis(mercaptomethylthio)ethyl)methane, tris(4,4-
bis(mercaptomethylthio)-2-thiabutyl)methane,
tetrakis(2,2-bis(mercaptomethylthio)ethyl)methane,
tetrakis(4,4-bis(mercaptomethylthio)-2-
thiabutyl)methane, 3,5,9,11-
tetrakis(mercaptomethylthio)-1,13-dimercapto- 2,6,8,12-
tetrathiatridecane, 3,5,9,11,15,17-
hexakis(mercaptomethylthio)-1,19-dimercapto-
2,6,8,12,14,18-hexathianonadecane, 9- (2,2-
bis(mercaptomethylthio)ethyl)-3,5,13, 15-
tetrakis(mercaptomethylthio)-1,17-dimercapto-
2,6,8,10,12,16-hexathiaheptadecane, 3,4,8,9-
tetrakis(mercaptomethylthio)-1,ll-dimercapto-2,5,7,10-
tetrathiaundecane, 3,4,8,9,13,14-
hexakis(mercaptomethylthio)-1,16-dimercapto-
2,5,7,10,12,15-hexathiahexadecane, 8-
[bis(mercaptomethylthio)methyl]-3,4,12,13-
tetrakis(mercaptomethylthio)-1,15-dimercapto-
2,5,7,9,11,14-hexathiapentadecane, 4,6-bis[3,5-
bis(mercaptomethylthio)-7-mercapto-2,6-
dithiaheptylthio]-1,3-dithian, 4-[3,5-
bis(mercaptomethylthio)-7-mercapto-2,6-
dithiaheptylthio]-6-mercaptomethylthio-l,3-dithian,
1,1-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-
1,3-bis(mercaptomethylthio)propane, 1- [ 4-(6-
mercaptomethylthio)-1,3-dithianylthio]-3-[2,2-
bis(mercaptomethylthio)ethyl] -7, 9-
bis(mercaptomethylthio)-2,4,6,10-tetrathiaundecane,
l,5-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-3-
[2-(1,3-dithiethanyl)]methyl-2,4-dithiapentane, 4,6-
bis{3-[2-(l,3-dithiethanyl)]methyl-5-mercapto-2,4-
dithiapentylthio}-!,3-dithian, 4,6-bis[4-(6-
mercaptomethylthio)-1,3-dithianylthio]-6-[4-(6-
mercaptomethylthio)-1,3-dithianylthio]-1,3-dithian, 3-
[2-(1,3-dithiethanyl)]methyl-7,9-
bis(mercaptomethylthio)-1,ll-dimercapto-2,4,6,10-
tetrathiaundecane, 9-[2-(1,3-dithiethanyl)]methyl-
3,5,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-
2,6,8,10,12,16-hexathiaheptadecane, 3- [2- (1,3-
dithiethanyl)]methyl-7,9,13,15-
tetrakis(mercaptomethylthio)-1,17-dimercapto-
2,4,6,10,12,16-hexathiaheptadecane, 3,7-bis[2-(l,3-
dithiethanyl)]methyl-1,9-dimereapto-2,4,6,8-
tetrathianonane, 4-[3,4,8,9-
tetrakis(mercaptomethylthio)-ll-mercapto-2, 5, 7, 10-
tetrathiaundecyl]-5-mercaptomethylthio-l,3-dithiolan,
4, 5-bis[3,4-bis(mercaptomethylthio)-6-mereapto-2,5-
dithiahexylthio]-!,3-dithiolan, 4- [3,4-
bis(mercaptomethylthio)-6-mercapto-2,5-
dithiahexylthio]-5-mercaptomethylthio-l,3-dithiolan, 4-
[3-bis(mercaptomethylthio)methyl-5,6-
bis(mercaptomethylthio)-8-mercapto-2 , 4, 7-trithiaoctyl]
5-mercaptomethylthio-l,3-dithiolan, 2-{bis [3,4-
bis(mercaptomethylthio)-6-mercapto-2,5-
dithiahexylthio]methyl}-!,3-dithiethane, 2- [3,4-
bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio^
mercaptomethylthiomethyl-1,3-dithiethane, 2-[3,4,8,9-
tetrakis(mercaptomethylthio)-ll-mercapto-2,5,7,10-
tetrathiaundecylthio] mercaptomethylthiomethyl-1,3-
dithiethane, 2-[3-bis(mercaptomethylthio)methyl-5,6-
bis(mercaptomethylthio)-8-mercapto-2,4,7-trithiaoctyl]
mercaptomethylthiomethyl-1,3-dithiethane, 4,5-bis{l-[2-
(1,3-dithiethanyl)]-3-mercapto-2-thiapropylthio}-1,3-
dithiolan, 4-{1- [2-(1,3-dithiethanyl) ]-3-mercapto-2-
thiapropylthio}-5-[1,2-bis(mercaptomethylthio)-4-
mercapto-3-thiabutylthio]-1,3-dithiolan, 2-{bis[4-(5-
mercaptomethylthio-1,3-dithiolanyl)thio]methyl}-1,3-
dithiethane, 4-[4-(5-mercaptomethylthio-l,3-
dithiolanyl)thio]-5-{l-[2-(l,3-dithiethanyl)]-3-
mercapto-2-thiapropylthio}-1,3-dithiolan, and their
polythiol compounds having dithioacetal or dithioketal
skeletons such as their oligomer or the like;
[0032]
tris(mercaptomethylthio)methane,
tris(mercaptoethylthio)methane, 1,1,5,5-
tetrakis(mercaptomethylthio)-2,4-dithiapentane,
bis[4,4-bis(mercaptomethylthio)-1,3-dithiabutyl]-
(mercaptomethylthio)methane, tris[4,4-
bis(mercaptomethylthio)-1,3-dithiabutyl]methane, 2,4,6-
tris(mercaptomethylthio)-1,3,5-trithiacyclohexane, 2, 4-
bis(mercaptomethylthio)-1,3,5-trithiacyclohexane,
1,1,3, 3-tetrakis(mercaptomethylthio)-2-thiapropane,
bis(mercaptomethyl)methylthio-l,3,5-trithiacyclohexane,
tris[(4-mercaptomethyl-2,5-dithiacyclohexyl-lyl)
methylthio]methane, 2,4-bis(mercaptomethylthio)-1,3-
dithiacyclopentane, 2-mercaptoethylthio-4-
mercaptomethyl-1,3-dithiacyclopentane, 2- (2,3-
dimercaptopropylthio)-1,3-dithiacyclopentane, 4-
mercaptomethyl-2-(2,3-dimercaptopropylthio)-1,3-
dithiacyclopentane, 4-mercaptomethyl-2-(1,3-dimercapto-
2-propylthio)-l,3-dithiacyclopentane, tris [2,2-
bis(mercaptomethylthio)-2-thiapropyl]methane, tris [ 4,4-
bis(mercaptomethylthio)-3-thiabutyl]methane, 2,4,6-
tris[3,3-bis(mercaptomethylthio)-2-thiapropyl]-1,3,5-
trithiacyclohexane, tetrakis[3,3-
bis(mercaptomethylthio)-2-thiapropyl]methane, or the
like, and compounds having ortho trithioformic ester
skeleton such as their oligomer, but are not limited
thereto. Furthermore, their halogen substituted
compounds such as chloro substituted compounds, bromo
substituted compounds or the like can be employed.
These compounds may be used individually or two or more
compounds may be used in combination.
[0033]
The polyhydroxy compound having at least two
hydroxy groups in one molecule and/or the
(poly)hydroxy(poly)mercapto compounds having at least
one hydroxy group and at least one thiol group in one
molecule may be a compound that has at least two
hydroxy groups only, or a compound in which the sum of
hydroxy group and thiol group in one molecule is two or
more. Specific examples may include compounds
containing mercapto groups and hydroxy groups, such as
2-mercaptoethanol, 3-mercapto-l,2-propanediol,
glycerinedi(mercaptoacetate),
glycerine-1,3-di(3-mercaptopropionate) ,
l-hydroxy-4-mercaptocyclohexane,
2-mercaptohydroquinone, 4-mercaptophenol,
1,3-dimercapto-2-propanol, 2,3-dimercapto-l-propanol,
1,2-dimercapto-l,3-butanediol,
pentaerythritol tris(3-mercaptopropionate),
pentaerythritol mono(3-mercaptopropionate),
pentaerythritol bis(3-mercaptopropionate),
pentaerythritol tris(thioglycolate),
dipentaerythritol pentakis(3-mercaptopropionate),
l-hydroxyethylthio-3-mercaptoethylthiobenzene,
bis(2-mercaptoacetate) malate,
2,4-dimercaptophenol,
hydroxymethyltris(mercaptoethylthiomethyl)methane,
l-hydroxyethylthio-3-mercaptoethylthiobenzene, 4-
hydroxy-4'-mercaptodiphenylsulfone, 2-(2-
mercaptoethylthio)ethanol, dihydroxyethylsulfidemono(3-
mercaptopropionate), dimercaptoethanemono(salicylate),
and hydroxyethylthiomethyltris(
mercaptoethylthiomethyl)methane.
[0034]
The compounds having two hydroxy groups include
polyols such as ethylene glycol, diethylene glycol,
propylene glycol, dipropylene glycol, butylenes glycol,
neopentyl glycol, glycerine, trimethylolethane,
trimethylolpropane, butanetriol, 1,2-methylglucoside,
pentaerythritol, dipentaerythritol, tripentaerythritol,
sorbitol, erythritol, treitol, ribitol, arabinitol,
xylitol, alytol, mannitol, dulcytol, iditol, glycol,
inocytol, hexanetriol, triglycerose, diglycerol,
triethylene glycol, polyethylene glycol, tris (2-
hydroxyethyl)isocyanurate, cyclobutanediol,
cyclopentanediol, cyclohexanediol, cycloheptanediol,
cyclooctanediol, cyclohexanedimethanol,
hydroxypropylcyclohexanol,
tricyclo[5.2.1.02'6]decanediol,
bicycle[4.3.0]nonanedimethanol,
tricyclo[5.3.1.1]dodecane-diethanol,
hydroxypropyltricyclo[5.3.1.1]dodecanol,
spiro[3.4]octanediol, butylcyclohexanediol, 1,1-
bicyclohexylidenediol, cyclohexanetriol, maltitol,
lactitol, dihydroxynaphthalene, trihydroxynaphthalene,
tetrahydroxynaphthalene, dihydroxybenzene, benzenetriol,
biphenyltetraol, pyrogallol,
(hydroxynaphthyl)pyrogallol, trihydroxyphenanthrene,
bisphenol A, bisphenol F, xyleneglycol, di(2-
hydroxyethoxy)benzene, bisphenol A-bis-(2-
hydroxyethylether), tetrabromobisphenol A,
tetrabronaobisphenol A-bis-(2-hydroxyethylether),
dibromoneopentyl glycol, epoxy resin, or the like;
condensed products of said polyols with organic acids
such as oxalic acid, glutamic acid, adipic acid, acetic
acid, propionic acid, cyclohexanecarboxylic acid, (3-
oxocyclohexanepropionic acid, dimeric acid, phthalic
acid, isophthalic acid, salicylic acid, 3-
bromopropionic acid, 2-bromoglycolic acid, dicarboxy
cyclohexane, pyromellitic acid, butane tetracarboxylic
acid, bromophthalic acid, or the like; addition
products of said polyols with alkyleneoxides such as
ethylene oxide, propylene oxide, or the like; addition
products of alkylenepolyamines with alkylene oxides
such as ethyleneoxide, propyleneoxide, or the like, but
are not limited thereto. Furthermore their halogen
substituted compounds such as chloro substituted
compounds, bromo substituted compounds, or the like may
be used.
[0035]
The compounds having at least two hydroxy groups
include polyol compound having (poly)sulfide bond such
as bis-[4-(hydroxyethoxy)phenyl]sulfide, bis-[4-(2-
hydroxypropoxy) phenyl]sulfide, bis-[4-(2,3-
dihydroxypropoxy)phenyl]sulfide, bis-[4-(4-
hydroxycyclohexyloxy)]sulfide, bis-[2-methyl-4-
(hydroxyethoxy)-6-butylphenyl]sulfide, and ethylene
oxide and/or propylene oxide adduct thereof in which,
per hydroxy group, average at most 3 molecules of the
ethylene oxide and/or propylene oxide are added, di-(2-
hydroxyethyl)sulfide, 1,2-bis- (2-
hydroxyethylmercapto)ethane, bis (2-
hydroxyethyl)disulfide, 1,4-dithian-2,5-diol, bis(2,3-
dihydroxypropyl)sulfide, tetrakis(4-hydroxy-2-
thiabutyl)methane, bis(4-hydroxyphenyl)sulfone(brand
name:bisphenol S), tetrabromobisphenol S,
tetramethylbisphenol S, 4 , 4'-thiobis(6-tert-butyl-3-
methylphenol), 1,3-bis(2-hydroxyethylthioethyl)-
cyclohexane, or the like, but are not limited thereto.
Furthermore their halogen substituted compounds such as
chloro substituted compounds, bromo substituted
compounds, or the like may be used. These compounds
may be used individually or two or more compounds may
be used in combination
[0036]
The polyalkyleneoxidepolyol represented by the
formula (4) is not specifically limited as long as m is
an integer of at least 0, but the range of m is
preferably 1 to 30, more preferably 1 to 20, and
especially preferablly 1 to 15.
[0037]
The ratio of the alicyclic isocyanate compounds
represented by the formula (1) or (2) to said polythiol
and the polyhydroxy compound having at least two
hydroxy groups in one molecule and/or the
(poly)hydroxy(poly)mercapto compound having at least
one hydroxy group and at least one thiol group in one
molecule to be used is usually in the range of 0.5 to
3.0 as mole ratio of the functional group NCO/(SH+OH),
preferably in the range of 0.5 to 1.5, and especially
preferably in the range of 0.8 to 1.2.
[0038]
Among the compounds described above, the resin
obtained by mixing and curing an 2,5-
bis(isocyanatomethyl)bicyclo[2,2,1]heptane as an
alicyclic isocyanate compound,
(a) 4-mercaptomethyl-l,8-dimercapto-3,6-dithiaoctane
as at least one compound of the polythiol compound
having at least two thiol groups in one molecule and/or
the polythiol compound having at least two thiol groups
and at least one (poly)sulfide bond other than the
thiol group in one molecule, and
(b) 2-mercaptoethanol as at least one compound of
the polyhydroxy compound having at least two hydroxy
groups in one molecule and/or the
(poly)hydroxy(poly)mercapto compound having at least
one hydroxy group and at least one thiol group in one
molecule, especially has high refractive index, high
Abbe number, high heat resistance, low specific gravity,
and sufficient resin strength in a balanced manner.
Further it has excellent tintability. Therefore it
brings about desired result.
[0039]
If the mole number of hydroxy group and thiol
group of the polyhydroxy compound having at least two
hydroxy groups in one molecule and/or the
(poly)hydroxy(poly)mercapto compound having at least
one hydroxy group and at least one thiol group in one
molecule, are A and B respectively, and the mole number
of the thiol group of the polythiol compound having at
least two thiol goup and/or the polythiol compound
having at least two thiol groups and at least one
(poly)sulfide bond other than thiol group in one
molecule, is C, A/(A+B+C) is preferably from 0.1 to
40%, more preferably from 3.0 to 35%, and particularly
preferably from 5.0 to 30%.
[0040]
The polyurethane lens of the present invention
comprises base resin having urethane bond and/or Salkyl
thiocarbamic acid ester bond by reaction of
isocyanate group with hydroxy group and/or thiol group.
However, according to the purpose, it may additionally
have an allophanate bond, a urea bond, or a biuret bond,
For example, it may often bring a desirable result if
the isocyanate group is further reacted with the
urethane bond or S-alkyl thiocarbamic acid ester bond
to increase the cross-link density. Such a reaction
may be carried out at a high temperature of at least
100° C and the isocyanate component should be used in
excess. Alternatively, an amine compound or the like
may additionally be used to produce a urea bond or a
biuret bond. As such, in the case of using the
compound other than the polyol compound, polythiol
compound or the thiol compound having hydroxy group
which are reacted with isocyanate compound, attention
should be paid to a coloring.
[0041]
Further, according to the purpose, likewise a
known molding method various additives such as a chain
extender, a cross-linking agent, a light stabilizer, an
ultraviolet absorber, an anti-oxidant, an oil-soluble
dye, filler, or the like may be used. In order to
obtain the desired reaction rate, a known reaction
catalyst useful in the manufacture of a S-alkyl
thiocarbamic acid ester or polyurethane can be used
suitably. The polyurethane lens of the present
invention can be commonly prepared by cast
polymerization.
[0042]
Specifically, the alicylic isocyanate compounds
represented by the formula (1) and/or the formula (2),
(a) at least one compound of the polythiol compound
having at least two thiol groups in one molecule and/or
the polythiol compound having at least two thiol groups
and at least one (poly)sulfide bond other than the
thiol group in one molecule, and
(b) at least one compound of the polyhydroxy compound
having at least two hydroxy groups in one molecule
and/or the (poly)hydroxy(poly)mercapto compound having
at least one hydroxy group and at least one thiol group
in one molecule, are mixed. The liguid mixture is
degasified if necessary by suitable method, then poured
into a mold, followed commonly by gradual heating from
lower temperature to higher temperature to polymerize.
[0043]
The polyurethane lens of the present invention
obtained in such manner has the characteristics such as
high refractive index and high Abbe number (low
dispersibility), excellent heat resistance, excellent
durability, and excellent resin strength with light
weighting. Therefore, it is suitable for optical
element material such as spectacle lens, camera lens,
or the like.
[0044]
The polyurethane lens of the present invention may
be subjected to physical or chemical treatment such as
surface abrasion treatment, antistatic treatment, hard
coat treatment, non-reflective coat treatment, dyeing
treatment and polarizing treatment for prevention of
reflection, enhancement of hardness, improvement of
abrasion resistance, improvement of chemical resistance,
prevention of turbidity, supply of fashionability, and
the like.
EXAMPLE
[0045]
Hereinafter, the invention will be further
specifically described by the following examples.
Among tests of the performance of the resins,
refractive index, heat resistance, specific gravity,
resin strength, and tintability were evaluated by the
following testing method.
Refractive index (ne) and Abbe number(ve):
Measured at 20°C with a Pulfrich refractometer.
• Heat resistance: Tg (°C) of the TMA
penetration method (50g of a load, pinpoint
O.SmmO) is measured as heat resistance.
Resin strength I (three points flexural
strength): Using AUTOGRAPH AGS-J
manufactured by Shimadzu Corporation, and
polyurethane lens test piece processed to a
dimension of 3.0mm of thickness, 70mm of
length and 24.0 mm of width, a load is
applied at the center of the lens test
piece with 1.2 mm/min of descending speed.
Maximum load (N/mm2) at the time of
breaking of the lens test piece was
measured.
Resin Strength II (Tensile Strength): Using
AUTOGRAPH AGS-J manufactured by Shimadzu
Corporation, and polyurethane lens test
piece processed to a dimension of 3.0mm of
thickness, 50mm of length and 6.0 mm of
width, the lens test piece is pulled from
the end-to-end at a pull rate of 1.0 mm/min
Maximum tensile strength (N/mm2) was
measured.
Tintability: To pure water, a disperse dye
for spectacle lens manufactured by Miikefi-
Senryo Ltd, vLP-Blue' 1.5g, 'MLP-Yellow'
2.0 g and 'MLP-Red' 1.5g as the staining
agent were added to prepare dye dispersion
solution. After heating the solution at
90°C, a plastic lens test piece having 9 mm
thicknesses were immersed in the solution
for 5 minutes at 90°C, to stain.
Transmittance of the lens test piece after
staining was measured at the wavelength of
430nm, 530nm, and 570nm. The basis of
evaluation is stated as follows. X
represents a transmittance of at least 50%,
A represents a transmittance of 50 to 30%,
o represents a transmittance of at most 30%
[0046]
[Example 1]
To 62.2g of 2,5-
bis(isocyanatomethyl)bicyclo[2.2.1]heptane, O.lOg of
dibuthyltin dichloride as a curing catalyst, 0.30g of
Zelec UN(acidic phosphoric ester), and 0.05g of viosorb
583(ultraviolet absorbent) were mixed and dissolved at
20°C. By adding 11.Bg of 2-mercaptoethanol, and 25.9g
of 4-mercaptomethyl-l,8-dimercapto-3,6-dithiaoctane,
mixed homogeneous solution was prepared. The rate of
mole number of hydroxy group was 25.2% with respect to
the sum of mole number of hydroxy group and thiol group
This homogeneous solution was degassed under the 600Pa
for 1 hour. After that, the solution was filtered
through lum PTFE filter. Then the resulting solution
was introduced to a mold equipped with glass mold and
tape. This mold was put into the oven, and the
temperature was slowly increased to 10 to 120 °C then
polymerized for 18 hours. After completion of
polymerization, mold was taken out from the oven, and
released to obtain a resin. The obtained resin was
additionally annealed at 120°C for three hours. The
obtained resin was colorless, high transparency and
good quality. Further it has 1.600 of Refractive index
(ne), 41 of Abbe number(ve), 119.1°C of heat
resistance(Tg), 1.27 of specific gravity, and 180N/mm2
of resin strength I (3 point flexural strength),
102N/mm2 of resin strength II (tensile strength). The
tintability was measured as o (transmittance of at most
30%) .
[0047]
Examples 2 to 5
The lenses of Examples 2 to 5 were prepared in the
same way as example 1, using the components shown in
Table 1-1 The evaluation results are shown in Table 2
Comparative Example 1
To 50.6g of 2,5-
bis(isocyanatomethyl)bicyclo[2.2.1]heptane, 0.02g of
dibuthyltin dichloride as a curing catalyst, 0.13g of
Zelec UN(acidic phosphoric ester), and O.OSg of Viosorb
583(ultraviolet absorbent) were mixed and dissolved at
20°C. By adding 23.9g of pentaerythritol tetrakis(3-
mercaptopropionate) and 25.5g of 4-mercaptomethyl-l,8-
dimercapto-3,6-dithiaoctane, mixed homogeneous solution
was prepared. This homogeneous solution was degassed
under the 600Pa for 1 hour. After that the solution
was filtered through lym PTFE filter. Then the
resulting solution was introduced to a mold equipped
with glass mold and tape. This mold was put into the
oven, and the temperature was slowly increased to 10 to
120°C then polymerized for 18 hours. After completion
of polymerization, mold was taken out from the oven,
and released to obtain a resin. The resin obtained was
additionally annealed at 120°C for three hours. The
obtained resin was colorless, high transparency, and
good quality. Further it has 1.5975 of Refractive
index(ne), 41 of Abbe number(ve), 121.9°C heat
resistance (Tg) , 1.29 of specific gravity, and 168 N/mm2
of resin strength I (3 point flexural strength),
92N/mm2 of resin strength II (tensile strength) . The
tintability was measured as o (transmittance of at most
30%) .
Comparative Examples 2 to 4
The lenses of Comparative Examples 2 to 4 were
prepared in the same way as Comparative Example I using
the components shown in Table 1-2. The evaluations are
shown in Table 2.
[0048]
The Symbol E, F, G, H of [Table 1-1] and [Table 1-
2] represent as follows:
: The alicyclic isocyanate compound. Number
represents the mole number of the isocyanate group.
F: The polythiol compound having at least two thiol
groups in one molecule and/or a polythiol compound
having at least two thiol groups and at least one
(poly)sulfide bond other than the thiol group in one
molecule. Number represents the mole number of the
thiol group.
G: The polyhydroxy compound having at least two
hydroxy groups in one molecule and/or the
(poly)hydroxy(poly)mercapto compound having at least
one hydroxy group and at least one thiol group. Number
represents the mole number of the thiol group, and
parenthetic number represents the mole number of the
hydroxy group.
H: If the mole number of hydroxy group and thiol
group of the polyhydroxy compound having at least two
hydroxy groups in one molecule and/or the
(poly)hydroxy(poly)mercapto compound having at least
one hydroxy group and at least one thiol group in one
molecule, are A and B respectively, and the mole number
of the thiol group of the polythiol compound having at
least two thiol group and/or the polythiol compound
having at least two thiol groups and at least one
(poly)sulfide bond other than the thiol group in one
molecule, is C, the rate(%) of the mole number of
hydroxy group to the sum of the mole number of thiol
group and the hydroxy group: 100 X A/(A+B+C)
(Figure Removed)
[Industrial Applicability]
[0052]
According to the present invention, transparent
curing resin having excellent balance of heat
resistance, specific gravity, and resin strength, and
further having excellent tintability is obtained as an
optical material of super high refractive index field.
41
Especially, the present invention contributes to
provide a material suitable for spectacle lens field

We Claim:
1. A polymerizable composition comprising an alicyclic isocyanate compound represented by the formula (1) and/or (2)

(Formula Removed)
(In the formula (1), n represents an integer of 0 to 3)

(Formula Removed)
(a) at least one compound of a polythiol compound having at least two thiol groups in one molecule and/or a polythiol compound having at least two thiol groups and at least one (poly) sulfide bond other than the thiol group in one molecule, and
(b) at least one compound of a polyhydroxy compound having at least two hydroxy groups in one molecule and/or a (poly) hydroxy (poly) mercapto compound having at least one hydroxy group and at least one thiol group in one molecule,
wherein those compounds are contained in the range of 0.5 to 3.0 as mole ratio of the functional group NCO/ (SH+OH).
The polymerizable composition as claimed in claim 1, wherein the
polythiol compound having at least two thiol groups in one molecule
and/or the polythiol compound having at least two thiol groups and at
least one (poly) sulfide bond other than the thiol group in one molecule,
is at least one polythiol compound selected from 4-mercaptomethyl-1, 8-
dimercapto-3, 6-dithiaoctane, 1,1,3,3-tetrakis (mercaptomethyl)-2-
thiapropane, 2, 5-bismercaptomethyl-l,4-dithiane,
bis(mercaptoethyl) sulfide, l,l,3,3-tetrakis(mercaptomethylthio)propane.

2-(2,2-bis{mercaptomethylthio)ethyl-l, 3-dithiethane, and 4,6-bis mercaptoethylthio-1, 3-dithiane.
3. The polymerizable composition as claimed in claim 1 or 2, wherein, if the mole number of hydroxy group and thiol group of the polyhydroxy compound having at least two hydroxy groups in one molecule and/or the (poly)hydroxy (poly)mercapto compound having at least one hydroxy group and at least one thiol group in one molecule, are A and B respectively, and the mole number of the thiol group of the polythiol compound having at least two thiol groups and/or the polythiol compound having at least two thiol groups and at least one (poly) sulfide bond other than the thiol group in one molecule, is C, A/(A+B+C) is from 0.1 to 40%.
4. The polymerizable composition as claimed in any one of claims 1, 2 and 3, wherein the polyhydroxy compound having at least two hydroxy groups in one molecule and/or the (poly)hydroxy {poly)mercapto compound having at least one hydroxy group and at least one thiol group in one molecule is at least one (poly)hydroxy group containing compound selected from (poly)hydroxy(poly) mercapto compound, 2-mercaptoethanol, 3-mercapto-l, 2-propanediol, pyrogallol, ethylene glycol, polycaprolactondiol, and polyalkyleneoxidepolyol represented by the formula (4)
(Formula Removed)

(wherein, m represents an integer).
The polymerizable composition as claimed in claim 1 or 3, wherein the alicyclic isocyanate compound is isocyanate compound of the formula (1), the polythiol compound having at least two thiol groups in one molecule and/or the polythiol compound having at least two thiol groups and at least one (poly) sulfide bond other than the thiol group in one

molecule, is 4-mercaptomethyl-l, 8-dimercapto-3, 6-dithiaoctane, or 4,8-dimercapto methyl-1, ll-mercapto-3,6,9-trithiaundecane, and the polyhydroxy compound having at least two hydroxy groups in one molecule and/or the (poly)hydroxy (poly)mercapto compound having at least one hydroxy group and at least one thiol group in one molecule, is 2-mercaptoethanol.
6. A process for producing a resin comprising:
curing the pol3anerizable composition as claimed in any one of claims 1 to 5 by gradual heating to polymerize.
7. A resin obtained by curing the polymerizable composition as claimed in any one of claims 1 and 2 to 5.
8. An optical element comprising the resin as claimed in claim 7.
9. A lens comprising the optical element as claimed in claim 8.