U.S. patent application number 10/056019 was filed with the patent office on 2002-10-17 for polyisocyanate compounds, process for producing the same, and optical materials using the same.
Invention is credited to Jiang, Jian, Kitahara, Yoshitaka.
Application Number | 20020151669 10/056019 |
Document ID | / |
Family ID | 26519869 |
Filed Date | 2002-10-17 |
United States Patent
Application |
20020151669 |
Kind Code |
A1 |
Kitahara, Yoshitaka ; et
al. |
October 17, 2002 |
Polyisocyanate compounds, process for producing the same, and
optical materials using the same
Abstract
The invention provides a novel polyisocyanate compound which is
useful as a starting material for an optical material having a high
refractive index, a low dispersion and excellent optical
characteristics, and a process for producing this compound at good
efficiency. The invention also provides an optical material having
a high refractive index, a low dispersion, an excellent
transparency without optical distortion and having good solvent
resistance and weatherability.
Inventors: |
Kitahara, Yoshitaka; (Tokyo,
JP) ; Jiang, Jian; (Tokyo, JP) |
Correspondence
Address: |
Raj S. Dave
Morrison & Foerster LLP
Suite 5500
2000 Pennsylvania Avenue, N.W.
Washington
DC
20006-1888
US
|
Family ID: |
26519869 |
Appl. No.: |
10/056019 |
Filed: |
January 28, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10056019 |
Jan 28, 2002 |
|
|
|
09362374 |
Jul 28, 1999 |
|
|
|
Current U.S.
Class: |
528/44 |
Current CPC
Class: |
C07C 323/25 20130101;
C08G 18/3876 20130101; C08G 18/775 20130101; G02B 1/041 20130101;
G02B 1/041 20130101; C08L 75/04 20130101 |
Class at
Publication: |
528/44 |
International
Class: |
C08G 018/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 29, 1998 |
JP |
H10-213570 |
Jul 29, 1998 |
JP |
H10-213571 |
Claims
What is claimed is:
1. A polyisocyanate compound of general formula (I) 20wherein n
represents an integer of from 1 to 4 and each of the indices n is
the same.
2. The polyisocyanate compound of claim 1, wherein said n is 1 or
2.
3. A process for producing a polyisocyanate compound represented by
general formula (I) 21wherein n represents an integer of from 1 to
4 and each of the indices n is the same, comprising: (a) reacting
1,2,3-trimercaptopropane with a halogeno-aliphatic carboxylic acid
lower alkyl ester represented by general formula (II)
X--CH.sub.2--(CH.sub.2).s- ub.m--COOR.sup.1 (II) wherein X
represents a halogen atom, R.sub.1 represents a lower alkyl group,
and m represents an integer of from 0 to 3, to obtain a
tricarboxylic acid ester represented by general formula (III) 22(b)
converting the tricarboxylic acid ester to a tricarbonyl hydrazide
represented by general formula (IV) 23and (c) converting the
tricarbonyl hydrazide group into an isocyanate group.
4. A process for producing a polyisocyanate compound represented by
general formula (I) 24wherein n represents an integer of from 1 to
4 and each of the indices n is the same, comprising: (a) reacting a
1,2,3-trihalogenopropane with a mercapto-aliphatic carboxylic acid
lower alkyl ester represented by general formula (V)
HS--CH.sub.2--(CH.sub.2).s- ub.m--COOR.sup.1 (V) wherein R.sup.1
represents a lower alkyl group, and m represents an integer of from
0 to 3, to obtain a tricarboxylic acid ester represented by general
formula (III) 25(b) converting the tricarboxylic acid ester to a
tricarbonyl hydrazide represented by general formula (IV) 26and (c)
converting the tricarbonyl hydrazide group into an isocyanate
group.
5. A process for producing a polyisocyanate compound represented by
general formula (I-a) 27wherein k represents an integer of from 0
to 2 and each of the indices k is the same, comprising: (a)
reacting 1,2,3-trimercaptopropane with an aliphatic unsaturated
carboxylic acid lower alkyl ester represented by general formula
(VI) CH.sub.2.dbd.CH--(CH.sub.2).sub.k--COOR.sup.2 (VI) wherein
R.sup.2 represents a lower alkyl group, to obtain a tricarboxylic
acid ester represented by general formula (VII) 28(b) converting
the tricarboxylic acid ester to a tricarbonyl hydrazide represented
by general formula (VIII) 29and (c) converting the tricarbonyl
hydrazide group into an isocyanate group.
6. A monomer mixture, comprising: component (A) comprising at least
a polyisocyanate compound represented by general formula (I)
30wherein n represents an integer of from 1 to 4 and each of the
indices n is the same, and component (B) comprising at least one
compound selected from the group consisting of (a) a compound
having two or more mercapto groups in a molecule, (b) a compound
having two or more hydroxyl groups in a molecule and (c) a compound
having one or more hydroxyl groups and one or more mercapto groups
in a molecule.
7. The optical material of claim 6, wherein said n is 1 or 2.
8. The optical material of claim 6 or 7, wherein the compound
having two or more mercapto groups in a molecule is a compound
represented by general formula (II-a) 31wherein p represents an
integer of from 1 to 20.
9. The optical material of claim 6 or 7, said material being
optically transparent.
10. An optical product formed of the optical material of claim 6 or
7.
11. The optical product of claim 10, said product being spectacle
lenses.
12. An optical material formed of a poly(thio)urethane which is
obtained by reacting the monomer mixture of claim 6.
Description
[0001] This application is based on Japanese patent application
Nos. H10-213570 and H10-213571, both filed on Jul. 29, 1998, the
entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a polyisocyanate compound and a
process for producing the same. In particular, it relates to a
novel polyisocyanate compound useful as a starting material for an
optical material, and a process for producing the same at good
efficiency. It also relates to an optical material and an optical
product using the same. Specifically, it relates to an optical
material which has excellent optical characteristics such as a high
refractive index, a low dispersion, an excellent transparency, lack
of optical distortion and the like, and which is also good in
solvent resistance and weatherability, and to an optical product
formed of this optical material, such as a lens, a prism, optical
fibers, a substrate for a recording medium, a filter, a glass, a
vase and the like.
BACKGROUND OF THE INVENTION
[0003] Recently, plastic materials have been used for optical parts
in place of inorganic glass, especially for eyeglass lenses,
because they are lightweight and have good dyeability and good
impact resistance. In particular, a polyethylene glycol
bisallylcarbonate polymer (hereinafter referred to as CR-39) and
polymethyl methacrylate (PMMA) have been used, primarily for
plastic lenses. However, it has a refractive index of 1.50, which
is lower than that of inorganic glass. Therefore, when they are
used as lens materials, for example, the thickness of the lenses
has to be increased with the increasing power. Consequently, not
only is the superiority of plastics as lightweight material been
impaired, but also they have not been preferred in view of the
aesthetic property. Furthermore, the concave lens, in particular,
has had problems when the thickness (edge thickness) of the
surrounding portion of the lens is increased causing a
birefringence or a chromatic aberration to occur.
[0004] For these reasons, in order to be able to decrease the
thickness of the lens while applying most of the characteristics of
plastics having a low specific gravity, a plastic material having a
high refractive index has been in demand. As a material having such
a performance, for example, (1) a polymer comprising a xylene
diisocyanate compound and a polythiol compound (official gazette of
JP-A-63-46213), (2) a resin comprising an aliphatic linear
sulfur-containing diisocyanate and a polythiol compound (official
gazette of JP-A-2-153302), (3) a polymer comprising a dithian
derivative substituted with two isocyanatoalkyl groups and a
polythiol (official gazette of JP-A-4-159275) are disclosed.
[0005] Although the polymer of item (1) has an increased refractive
index by limiting a combination with the polythiol compound to be
polymerized, it gives rise to problems that an Abbe number is
decreased and a chromatic aberration is increased.
[0006] Meanwhile, the resin (2) and the polymer (3) have a high
refractive index and the improvement in the chromatic aberration is
found therein, but they have a defect that a solvent resistance is
poor.
[0007] Furthermore, since these prior art polymers are
uncrosslinked polymers obtained from bifunctional isocyanate
compounds, a special crosslinking agent is needed separately to
improve a solvent resistance. Thus, the types of the polythiol
compounds that can be polymerized are limited.
SUMMARY OF THE INVENTION
[0008] In order to overcome many of the problems in the prior art,
the invention provides an optical material having the
above-mentioned desirable properties. It is a feature of the
invention to provide a novel polyisocyanate compound that can give
an optical material having a high refractive index, a low
dispersion and an excellent solvent resistance and weatherability,
and a process for producing this compound at good efficiency. It is
also a feature of the invention to provide an optical material
which has excellent optical characteristics such as a high
refractive index, a low dispersion, an excellent transparency, lack
of optical distortion and the like, and which has good solvent
resistance and weatherability, and an optical product formed of
this optical material.
[0009] In particular, the invention provides a polyisocyanate
compound having sulfur atoms, contributing to a high refractive
index and a low dispersion, in a main skeleton and having three
isocyanates as polymerization functional groups. In addition, the
invention provides methods for producing the polyisocyanate
compound by an efficient processes. It also provides an optical
material formed of a poly(thio)urethane obtained by subjecting a
component comprising a polyisocyanate compound and a component
comprising a compound having two or more of hydroxyl groups or
mercapto or both groups to a polyaddition reaction.
[0010] In one aspect, the invention provides a polyisocyanate
compound having general formula (I) 1
[0011] wherein n represents an integer from 1 to 4 and each of the
indices n is the same.
[0012] In another embodiment, the polyisocyanate compound can be
produced by one of the following processes: production process 1,
production process 2 and production process 3.
[0013] Production process 1 of the invention is a process for
producing a polyisocyanate compound represented by general formula
(I).
[0014] Process 1 comprises:
[0015] (a) reacting 1,2,3-trimercaptopropane with a
halogeno-aliphatic carboxylic acid lower alkyl ester represented by
general formula (II)
X--CH.sub.2--(CH.sub.2).sub.m--COOR.sup.1 (II)
[0016] wherein X represents a halogen atom, R.sup.1 represents a
lower alkyl group, and m represents an integer of from 0 to 3, to
obtain a tricarboxylic acid ester represented by general formula
(III) 2
[0017] wherein n and R.sup.1 are as defined above,
[0018] (b) converting the tricarboxylic acid ester to a tricarbonyl
hydrazide represented by general formula (IV) 3
[0019] wherein n is as defined above,
[0020] and
[0021] (c) converting the carbonyl hydrazide group into an
isocyanate group.
[0022] Production process 2 of the invention is a process for
producing a polyisocyanate compound represented by general formula
(I).
[0023] Process 2 comprises:
[0024] (a) reacting a 1,2,3-trihalogenopropane with a
mercapto-aliphatic carboxylic acid lower alkyl ester represented by
general formula (V)
HS--CH.sub.2--(CH.sub.2).sub.m--COOR.sup.1 (V)
[0025] wherein R.sup.1 represents a lower alkyl group, and m
represents an integer of from 0 to 3, to obtain a tricarboxylic
acid ester represented by general formula (III),
[0026] (b) converting the tricarboxylic acid ester to tricarbonyl
hydrazide represented by general formula (IV) 4
[0027] wherein n is as defined above, and
[0028] (c) converting the carbonyl hydrazide group into an
isocyanate group.
[0029] Production process 3 of the invention is a process for
producing a polyisocyanate compound represented by general formula
(I-a) 5
[0030] wherein k represents an integer of from 0 to 2 and each of
the indices k is the same.
[0031] Process 3 comprises:
[0032] (a) reacting 1,2,3-trimercaptopropane with an aliphatic
unsaturated carboxylic acid lower alkyl ester represented by
general formula (VI)
CH.sub.2=CH--(CH.sub.2).sub.k--COOR.sup.2 (VI)
[0033] wherein R.sup.2 represents a lower alkyl group, and k is as
defined above, to obtain a tricarboxylic acid ester represented by
general formula (VII) 6
[0034] wherein R.sup.2 and k are as defined above,
[0035] (b) converting the tricarboxylic acid ester to tricarbonyl
hydrazide represented by general formula (VIII) 7
[0036] wherein k is as defined above, and
[0037] (c) converting the carbonyl hydrazide group into an
isocyanate group.
[0038] In another embodiment, the optical material of the invention
is formed of a poly(thio)urethane, which is obtained by subjecting
a monomer mixture comprising component (A) comprising at least a
polyisocyanate compound represented by general formula (I), wherein
n represents an integer of from 1 to 4, and component (B)
comprising at least one type selected from (a) a compound having
two or more mercapto groups in a molecule, (b) a compound having
two or more hydroxyl groups in a molecule and (c) a compound having
one or more hydroxyl groups and one or more mercapto groups in a
molecule to a polyaddition reaction.
[0039] The invention is to provide an optical product formed of the
above-mentioned optical material.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The invention will be better understood by reference to the
Detailed Description of the Invention when taken together with the
drawings, wherein:
[0041] FIG. 1 shows an .sup.1H-NMR spectrum of
1,2,3-tris(isocyanatoethylt- hio)propane obtained in Production
Example 1.
[0042] FIG. 2 shows an IR spectrum of
1,2,3-tris(isocyanatoethylthio)propa- ne obtained in Production
Example 1.
DETAILED DESCRIPTION OF THE INVENTION
[0043] The polyisocyanate of the invention is a novel compound
represented by general formula (I). As is apparent from general
formula (I), this novel compound has a structure in which sulfur
atoms are bound to the 1-, 2- and 3-positions of propane,
respectively, and three isocyanate groups are further provided.
Since the sulfur atoms are thus provided in the structure, i.e.,
the basic skeleton, the refractive index and the Abbe number of the
polyisocyanate compound itself are increased. Accordingly, when an
optical material is produced using the polyisocyanate compound, the
refractive index and the Abbe number of the optical material are
also increased. Furthermore, since the polyisocyanate compound has
three isocyanate groups, it also works as a crosslinking agent.
Accordingly, when the optical material is produced using the
polyisocyanate compound, not only a high solvent resistance but
also a high heat resistance and excellent mechanical properties can
be imparted to the optical material without adding another
crosslinking agent as a secondary component. In the polyisocyanate
compound, a compound in which n in general formula (I) is 1 or 2 is
especially preferable.
[0044] When the polyisocyanate compound represented by general
formula (I) is used, there is no need to use a crosslinking agent,
but a crosslinking agent can also be used conjointly if
required.
[0045] Examples of the polyisocyanate compound represented by
general formula (I)
[0046] are the following: 8
[0047] The process for producing the polyisocyanate compound
represented by general formula (I) may be any process by which a
polyisocyanate compound having a desired structure can be produced.
However, it can be produced at quite good efficiency according to
the processes 1, 2 and 3 of the invention as mentioned below.
[0048] Production process 1:
[0049] In this production process 1, first,
1,2,3-trimercaptopropane is reacted with a halogeno-aliphatic
carboxylic acid lower alkyl ester represented by general formula
(II)
X--CH.sub.2--(CH.sub.2).sub.m--COOR.sub.1 (II)
[0050] wherein X represents a halogen atom, R.sup.1 represents a
lower alkyl group, and m represents an integer of from 0 to 3, to
form a tricarboxylic acid ester represented by general formula
(III) 9
[0051] wherein n is an integer of from 1 to 4, each of the indices
n is the same and R' is as defined above.
[0052] In this reaction, it is preferable that 1 mol of
1,2,3-trimercaptopropane is reacted with substantially 3 moles of
the halogeno-aliphatic carboxylic acid lower alkyl ester
represented by general formula (II) in the presence of a hydrogen
halide trapping agent. In this case, an appropriate solvent can be
used as required.
[0053] The tricarboxylic acid ester represented by general formula
(III) is reacted with hydrazine monohydrate or the like to lead the
same to a tricarbonyl hydrazide represented by general formula (IV)
10
[0054] wherein n is as defined above. At this time, a solvent such
as a lower alcohol or the like can be used as required.
[0055] Finally, the tricarbonyl hydrazide represented by general
formula (IV) is reacted with nitrous acid in, for example, a
hydrochloric acid aqueous solution to form carbonyl azide, and the
heat transfer is conducted to convert a carbonyl azide group into
an isocyanate group, whereby a desired polyisocyanate compound
represented by general formula (I) 11
[0056] wherein n is as defined above, is obtained.
[0057] Production Process 2:
[0058] In this production process 2, first, the
1,2,3-trihalogenopropane is reacted with a mercapto-aliphatic
carboxylic acid lower alkyl ester represented by general formula
(V).
HS--CH.sub.2--(CH.sub.2).sub.m--COOR.sup.1 (V)
[0059] wherein R.sup.1 represents a lower alkyl group, and m
represents an integer of from 0 to 3, to obtain a tricarboxylic
acid ester represented by general formula (III) 12
[0060] wherein n and R.sup.1 are as defined above.
[0061] In this reaction, it is preferable that 1 mol of the
1,2,3-trihalogenopropane is reacted with substantially 3 moles of
the mercapto-aliphatic carboxylic acid lower alkyl ester
represented by general formula (V) in the presence of a hydrogen
halide trapping agent. In this case, an appropriate solvent can be
used as required.
[0062] Subsequently, the tricarboxylic acid ester represented by
general formula (III) is, as in the above-mentioned production
process 1, led to a carbonyl hydrazide, and a carbonyl hydrazide
group is then converted into an isocyanate group to obtain a
desired polyisocyanate compound represented by general formula
(I).
[0063] Production Process 3:
[0064] The production process 3 is a process for producing a
polyisocyanate compound in which n in general formula (I) is
between 2 and 4.
[0065] In this production process 3, first,
1,2,3-trimercaptopropane is reacted with an aliphatic unsaturated
carboxylic acid lower alkyl ester represented by general formula
(VI)
CH.sub.2.dbd.CH--(CH.sub.2).sub.k--COOR.sup.2 (VI)
[0066] wherein R.sup.2 represents a lower alkyl group, and k
represents an integer of from 0 to 2, to obtain a tricarboxylic
acid ester represented by general formula (VII) 13
[0067] wherein R.sup.2 and k are as defined above.
[0068] In this reaction, it is preferable that 1 mol of
1,2,3-trimercaptopropane is reacted with substantially 3 moles of
the aliphatic unsaturated carboxylic acid lower alkyl ester
represented by general formula (VI) in the presence of a radical or
anionic catalyst. In this case, an appropriate solvent can be used
as required.
[0069] Subsequently, the tricarboxylic acid ester represented by
general formula (VII) is reacted with hydrazine monohydrate or the
like to lead the sane to a tricarbonyl hydrazide represented by
general formula (VIII) 14
[0070] wherein k is as defined above. In this case, a solvent such
as a lower alcohol can be used as required.
[0071] Finally, the tricarbonyl hydrazide represented by general
formula (VIII) is reacted with nitrous acid in, for example, a
hydrochloric acid aqueous solution to form carbonyl azide, and the
heat transfer is conducted to convert a carbonyl azide group into
an isocyanate group, whereby a desired polyisocyanate compound
represented by general formula (I-a) 15
[0072] wherein k is as defined above, is obtained.
[0073] Incidentally, the lower alkyl group indicated at R.sup.1 and
R.sup.2 is a methyl group, an ethyl group, an n-propyl group, an
isopropyl group or the like.
[0074] The polyisocyanate compound represented by general formula
(I) can also be produced by a phosgene method other than the
above-mentioned processes of the invention.
[0075] The phosgene method is described by taking an example.
First, 1 mol of the 1,2,3-trimercaptopropane is reacted with
substantially 3 moles of a halogenoacetonitrile in the presence of
a hydrogen halide trapping agent to obtain
1,2,3-tris(cyanomethylthio)propane represented by formula (IX)
16
[0076] Then, the compound represented by general formula (IX) is
subjected to hydrogenation to lead it to
1,2,3-tris(aminoethylthio)propane represented by general formula
(X) 17
[0077] Then, the compound represented by general formula (X) is
reacted with phosgene to obtain desired
1,2,3-tris(isocyanatoethylthio)propane represented by formula (I-b)
18
[0078] Component (A) may contain, to appropriately improve
properties and the like of the optical material, one or two or more
types of a compound having two or more isocyanate groups in a
molecule other than the polyisocyanate compound represented by the
above-mentioned general formula (I). Specific examples of these
compounds include o-xylene diisocyanate, m-xylene diisocyanate,
p-xylene diisocyanate,
.alpha.,.alpha.,.alpha.',.alpha.'-tetramethyl-p-xylene
diisocyanate,
.alpha.,.alpha.,.alpha.',.alpha.'-tetramethyl-m-xylene
diisocyanate, 1,3,5-tris(isocyanatomethyl)benzene, hexamethylene
diisocyanate, 1,4-diisocyanatobutane, isophorone diisocyanate,
norbomene diisocyanate, bis(4,4'-isocyanatocyclohexyl)methane,
1,3-bis(isocyanatomethyl)cyclohexa- ne,
1,3,5-tris(isocyanatomethyl)cyclohexane,
1,4-diisocyanatocyclohexane, 1,3,5-triisocyanatocyclohexane, lysine
triisocyanate, 2,5-bis(isocyanatomethyl)-1,4-dithian,
1,3-dithiolan-4,5-diisocyanate,
4,5-bis(isocyanatomethyl)-1,3-dithiolan, isocyanatomethyl sulfide,
2-isocyanatoethyl sulfide, bis(isocyanatomethylthio)methane,
1,2-bis(isocyanatomethylthio)ethane,
bis(2-isocyanatoethylthio)methane,
1,2-bis(2-isocyanatoethylthio)ethane,
1,7-diisocyanato-2,4,6-trithiahepta- ne,
1,5-diisocyanato-2-isocyanatomethyl-3-thiapentane,
1,4-diisocyanato-2-isocyanatomethyl-3-thiabutane and the like.
[0079] The content of the polyisocyanate compound represented by
general formula (I) in the component (A) is preferably 0.1 mol % or
more, especially preferably 5 mol % or more.
[0080] Component (B), another starting material of the
poly(thio)urethane, a component comprising at least one type
selected from (a) a compound having two or more mercapto groups in
a molecule, (b) a compound having two or more hydroxyl groups in a
molecule and (c) a compound having one or more hydroxyl groups and
one or more mercapto groups in a molecule is used.
[0081] Examples of the compound having two or more mercapto groups
in a molecule as the component (a) here include
2,5-bis(mercaptomethyl)-1,4-di- thian,
2,5-bis(mercaptomethyl)-1,4-dithian dimer and polymer (trimer or
higher polymer), 1,2,3-trimercaptopropane,
tetrakis(7-mercapto-2,5-dithia- heptyl)methane, 1,2-ethanedithiol,
1,3-propanedithiol, tetrakismercaptomethylmethane, 2-mercaptoethyl
sulfide, pentaerythritol tetrakismercaptopropionate,
pentaerythritol tetrakismercaptoacetate, 1,2-benzenedithiol,
1,3-benzenedithiol, 1,4-benzenedithiol, 1,3,5-benzenetrithiol,
1,2-dimercaptomethylbenzene, 1,3-dimercaptomethylbenzene,
1,4dimercaptomethylbenzene, 1,3,5-trimercaptomethylbenzene,
toluene-3,4-dithiol, tris(3-mercaptopropyl) isocyanurate,
1,3-bis(mercaptomethyl)cyclohexane,
1,4-bis(mercaptomethyl)cyclohexane, 2,2-bis(mercaptomethyl)-1
,3-propanedithiol, 1,2-bis(2-mercaptoethylthio)-3-mercaptopropane,
4,8-bis(mercaptomethyl)-3,6,9-trithia-1,11-undecanedithiol and the
like.
[0082] Examples of the compound having two or more hydroxyl groups
in a molecule as the component (b) include ethylene glycol,
trimethylolpropane, glycerin, dihydroxybenzene, catechol,
4,4'-dihydroxyphenyl sulfide, 2-hydroxyethyl sulfide, bisphenol
A.multidot.propylene oxide 5-mol adduct, glycerin-propylene oxide
3-mol adduct and the like.
[0083] Examples of the compound having one or more hydroxyl groups
and one or more mercapto groups in a molecule as the component (c)
include 2-mercaptoethanol, 2,3-dimercaptopropanol,
1,2-dihydroxy-3-mercaptopropan- e, 4-mercaptophenol and the
like.
[0084] As component (B), a mercapto group-containing compound is
preferable. Especially, 2,5-bis(mercaptomethyl)-1,4-dithian and its
oligomer represented by general formula (I-a) 19
[0085] wherein p is an integer of from 1 to 20, and oligomers
thereof are preferable.
[0086] With respect to the ratio of the component (A) to the
component (B) in the invention, it is preferable that the molar
ratio of the isocyanate group in the component (A) to the total
amount of the mercapto group and the hydroxyl group in the
component (B), NCO group/(SH group+OH group), is in the range of
from 0.95 to 1.05.
[0087] The monomer mixture comprising the component (A) and the
component (B) may contain one or two or more types of the compound
having two or more vinyl groups in the molecule to appropriately
improve the properties and the like of the optical material in
addition to the components (A) and (B). With respect to the ratio
of these compounds used at this time, it is preferable that the
(isocyanate group +vinyl group)/(mercapto group +hydroxyl group)
molar ratio is in the range of from 0.95 to 1.5 and the (vinyl
group)/(isocyanate group) molar ratio is 0.7 or less, and that
polymerizable functional groups contained in the component (B) are
all mercapto groups. Specific examples of these compounds include
2,5-bis(2-thia-3-butenyl)-1,4-dithian, divinylbenzene, ethylene
glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, a
urethane-modified (meth)acrylate comprising at least two
(meth)acryloxy groups in a molecule and the like. By the way, the
above-mentioned (meth)acrylate means both of an acrylate and a
methacrylate, and the (meth)acryloxy group means both of an
acryloxy group and a methacryloxy group.
[0088] To the optical material of the invention can be added an
ultraviolet absorber, a coloring matter, a pigment and the like for
improving light absorption characteristics, an antioxidant, a
coloration inhibitor and the like for improving a weatherability,
and a release agent and the like for improving a moldability, as
required.
[0089] Examples of the ultraviolet absorber include a benzotriazole
type, a benzophenone type, a salicylic acid type and the like.
Examples of the coloring matter and the pigment include an
anthraquinone type, an azo type and the like.
[0090] Examples of the antioxidant and the coloration inhibitor
include a monophenol type, a bisphenol type, a high-molecular
phenol type, a sulfur type, a phosphorus type and the like.
Examples of the release agent include a fluorine-type surfactant, a
silicone-type surfactant, an acidic phosphate, a higher fatty acid
and the like.
[0091] A catalyst may be used, as required, to improve
polymerization. For example, an amine compound, an organic metal
compound and the like are effective. Specific examples thereof
include triethylenediamine, hexamethylenetetramine,
N,N-dimethyloctylamine, N,N,N',N'-tetramethyl-1,6- -diaminohexane,
4,4'-trimethylenebis(1-methylpiperidine),
1,8-diazabicyclo-(5,4,0)-7-undecene, dimethyltin dichloride,
dimethyltin bis(isooctylthioglycolate), dibutyltin dichloride,
dibutyltin dilaurate, dibutyltin maleate, dibutyltin maleate
polymer, dibutyltin diricinoleate, dibutyltin
bis(dodecylmercaptide), dibutyltin bis(isooctylthioglycolate),
dioctyltin dichloride, dioctyltin maleate, dioctyltin maleate
polymer, dioctyltin bis(butylmaleate), dioctyltin dilaurate,
dioctyltin diricinoleate, dioctyltin dioleate, dioctyltin
di(6-hydroxy)caproate, dioctyltin bis(isooctylthioglycokate),
didodecyltin diricinoleate, copper oleate, copper acetylacetonate,
iron acetylacetonate, iron naphthenate, iron lactate, iron citrate,
iron gluconate, potassium octanate, 2-ethylhexyl titanate and the
like. The above-mentioned catalysts are effectively used either
singly or in combination of two or more types.
[0092] When a vinyl compound is contained in the monomer mixture,
the use of an organic peroxide, an azo compound or the like other
than the above-mentioned catalyst is also effective.
[0093] An optical material using the polyisocyanate compound of the
invention can be produced. The following is but one example.
[0094] A uniform mixture of the component (A), the component (B),
the additives and the catalyst is subjected to a known cast
polymerization method. That is, it is cast into a die which is a
combination of a glass or metal mold and a gasket made of a resin,
and cured by heating. In order to expedite withdrawal of the resin
after molding, the mold may previously be subjected to release
agent treatment, or a release agent may be added to the mixture of
the component (A), the component (B) and the like. The
polymerization temperature varies depending on the compound used.
It is usually between -20 and +150.degree. C. The polymerization
time is between 0.5 and 72 hours. The optical material of the
invention can easily be dyed in water or an organic solvent using
an ordinary disperse dye. At this time, for further expediting the
dyeing, a carrier may be added or heating may be conducted. The
optical material is used as a plastic lens especially preferably,
but is not limited thereto.
EXAMPLES
[0095] The invention is illustrated more specifically by referring
to the following Examples. However, the invention is not intended
to be limited to these Examples.
[0096] The properties of the polyisocyanate compounds and optical
materials (polymers) were evaluated according to the following
methods:
[0097] (1) .sup.1H-NMR spectrum (proton nuclear magnetic resonance
spectrum): Measured using an FT-NMR Device EX 270 Model supplied by
JEOL.
[0098] (2) IR spectrum (infrared absorption spectrum): Measured
using a MAGNA-IR Spectrometer 560 Model supplied by Nicolet.
[0099] (3) Refractive index (n.sub.D) and Abbe number (VD):
Measured at 20.degree. C. using a precision refractometer KPR-200
Model supplied by Kalnew.
[0100] (4) Appearance: Visually observed.
[0101] (5) Weatherability: A lens (optical product using an optical
material) was mounted on a weather meter fitted with a sunshine
carbon arc lamp. When 200 hours passed, the lens was taken out, and
the color thereof was compared with that of the lens before the
test. The weatherability was evaluated according to the following
standard.
[0102] .smallcircle.: unchanged
[0103] .DELTA.: slightly yellowed
[0104] .times.: yellowed
[0105] (6) Solvent resistance: A wiping test using acetone was
conducted, and the solvent resistance was evaluated according to
the following standard.
[0106] .smallcircle.: unchanged
[0107] .times.: The surface is roughened or swollen.
[0108] (7) Optical distortion: Visually observed by the Schlieren
method. The optical distortion was evaluated according to the
following standard.
[0109] .smallcircle.: No distortion is observed.
[0110] .times.: Distortion is observed.
Example 1
Production of 1,2,3-tris(isocyanatoethylthio)propane
[0111] 1,2,3-Trismercaptopropane (28.0 g, 0.20 moles) and 51.7 g
(0.6 moles) of methyl acrylate were dissolved in 300 ml of
chloroform. Triton B (40% by weight methanol solution, 0.6 g) was
added as a catalyst in an ice bath, and the solution was stirred
under reflux for 3 hours. The reaction solution was allowed to
cool, then washed with a dilute sodium hydroxide aqueous solution
and with water in this order, and dried over magnesium sulfate.
Thereafter, chloroform was fully removed to obtain 71.5 g (0.18
moles) of colorless transparent 1,2,3-tris(methyloxycarbonyl-
ethylthio)propane.
[0112] The ester compound was dissolved in 50 ml of methanol, and
added dropwise to a mixed solution of 81.0 g (1.62 moles) of
hydrazine monohydrate and 90 ml of methanol at room temperature.
After the completion of the dropwise addition, the mixture was
stirred at 70.degree. C. for 4 hours. After the mixture was allowed
to cool, white crystals precipitated were collected through
filtration, and recrystallized from methanol-water to obtain 69.4 g
(0.17 moles) of 1,2,3-tris(hydrazinocarbonylethylthio)propane.
[0113] The hydrazide compound was dissolved in 280 g of a 7.2% by
weight hydrochloric acid aqueous solution, and 36.1 g (0.52 moles)
of sodium nitrite were added to a suspension with 160 ml of
toluene. After the completion of the addition, the stirring was
continued for 1 hour. The organic phase was extracted from the
suspension, washed with water, dried (magnesium sulfate), and then
heated to complete the transition reaction. Toluene as a solvent
was fully removed from the reaction solution to obtain 46.0 g (0.13
moles) of a colorless transparent reaction product. This reaction
product was identified to be a desired polyisocyanate compound from
the .sup.1H-NMR spectrum and the IR spectrum. The .sup.1H-NMR
spectrum of this novel polyisocyanate compound is shown in FIG. 1,
and the IR spectrum thereof in FIG. 2.
Application Example 1
[0114] A mixture of 0.08 moles of
1,2,3-tris(isocyanatoethylthio)propane (designated SP-1 in Table 1)
obtained in Example 1, 0.12 moles of
2,5-bis(mercaptomethyl)-1,4-dithian dimer (designated DBMD in Table
1) and 1.2.times.10.sup.-4 moles of dibutyltin dilaurate
(designated DBTDL in Table 1) was uniformly stirred, and cast into
glass molds for forming a lens. The mixture was polymerized at
50.degree. C. for 10 hours, then at 60.degree. C. for 5 hours and
further at 120.degree. C. for 3 hours to obtain a plastic lens. The
properties of the resulting plastic lens are shown in Table 1. From
Table 1, it was found that the polymer obtained by using the
polyisocyanate compound of Example 1 was colorless and transparent,
the refractive index (n.sub.D) was as high as 1.69, the Abbe number
(v.sub.D) was also as high as 36 (low dispersion), the
weatherability and the solvent resistance were excellent, and no
optical distortion was observed.
Application Examples 2 to 6
[0115] The same procedure as in Application Example 1 was conducted
except using a monomer composition comprising the polyisocyanate
compound SP-1 [1,2,3-tris(isocyanatoethylthio)propane] obtained in
Example 1 or 1,2,3-tris(isocyanatomethylthio)propane (designated
SP-2 in Table 1) as shown in Table 1 to obtain a plastic lens. The
properties of these plastic lenses were shown in Table 1. From
Table 1, it was found that the resulting plastic lenses were
colorless and transparent, the refractive index (n.sub.D) was as
high as between 1.65 and 1.70, the Abbe number (.nu..sub.D) was
also as high as between 34 and 39 (low dispersion), the
weatherability and the solvent resistance were excellent, and no
optical distortion was observed.
Application Comparative Example 1
[0116] A mixture of 0.06 moles of pentaerythritol
tetrakismercaptopropiona- te (designated PETMP in Table 1), 0.12
moles of m-xylene diisocyanate (designated XDI in Table 1) and
1.2.times.10.sup.4 moles of dibutyltin dilaurate (designated DBTDL
in Table 1) was uniformly stirred, and cast into glass molds for
forming a lens. The mixture was polymerized at 50.degree. C. for 10
hours, then at 60.degree. C. for 5 hours and further at 120.degree.
C. for 3 hours to obtain a plastic lens. The properties of the
resulting plastic lens are shown in Table 1. From Table 1, it was
found that the plastic lens in Application Comparative Example 1
was colorless and transparent, no optical distortion was observed,
and the solvent resistance was excellent, but the refractive index
was as low as 1.59.
[0117] Application Comparative Examples 2 and 3
[0118] The same procedure as in Application Comparative Example 1
was conducted except using monomer compositions shown in Table 1 to
obtain plastic lenses. The properties of these plastic lenses were
shown in Table 1. From Table 1, it was found that the plastic lens
in Application Comparative Example 2 had a high refractive index of
1.68 and was excellent in the solvent resistance. However, it was
colored yellow, the Abbe number was as low as 25, the
weatherability was poor, and the optical distortion was observed.
Further, the plastic lens in Application Comparative Example 3 was
colorless and transparent, the refractive index was as high as
1.68, and no optical distortion was observed. However, the Abbe
number was as low as 29, and the solvent resistance was also
poor.
1 TABLE 1 Component (A) Component (B) Catalyst Solvent Optical
(mol) (mol) (mol) n.sub.D/v.sub.D Appearance Weatherability
resistance distortion Application Example 1 SP-1 (0.08) DBMD (0.12)
DBTDL 1.69/36 colorless, .largecircle. .largecircle. .largecircle.
(1.2 .times. 10.sup.-4) transparent 2 SP-1 (0.04) BMMD (0.12) DBTDC
1.65/39 colorless, .largecircle. .largecircle. .largecircle. IPDI
(0.06) (1.2 .times. 10.sup.-4) transparent 3 SP-1 (0.10) TMP (0.10)
DBTDL 1.66/37 colorless, .largecircle. .largecircle. .largecircle.
(1.5 .times. 10.sup.-4) transparent 4 SP-2 (0.08) BMMD (0.12) DMTDC
1.67/36 colorless, .largecircle. .largecircle. .largecircle. (1.2
.times. 10.sup.-4) transparent .largecircle. .largecircle.
.largecircle. 5 SP-2 (0.10) BMMC (0.06) DBTDL 1.66/39 colorless,
.largecircle. .largecircle. .largecircle. TMP (0.06) (1.5 .times.
10.sup.-4) transparent 6 SP-2 (0.04) DBMD (0.12) DMTDC 1.70/34
colorless, .largecircle. .largecircle. .largecircle. IMTM (0.06)
(1.2 .times. 10.sup.-4) transparent Application Comparative Example
1 XDI (0.12) PETMP (0.06) DBTDL 1.59/35 colorless .DELTA.
.largecircle. .largecircle. (1.2 .times. 10.sup.-4) transparent 2
TDI (0.12) XDT (0.07) DBTDL 1.68/25 yellow X .largecircle. X PETMA
(0.025) (1.2 .times. 10.sup.-4) 3 TPDI (0.10) XDT (0.10) DBTDL
1.68/29 colorless .DELTA. X .largecircle. (1.0 .times. 10.sup.-4)
transparent Note: SP-1: 1,2,3-tris(isocyanatoethylthio)propane,
SP-2: 1,2,3-tris(isocyanatomethylthio)propane, IPDI: isophorone
diisocyanate, IMTM: bis(isocyanatomethylthio)methane, DBMD:
2,5-bis(mercaptomethyl)-1,4-dithian dimer, BMMD:
2,5-bis(mercaptomethyl)-1,4-dithian, BMMC:
2,5-bis(mercaptomethyl)cyclohexane,, TMP: 1,2,3-trimercaptopropan-
e, DBTDL: di-n-butyltin dilaurate, DMTDL: dimethyl tin-dichloride,
DBTDC: di-n-butyltin dichloride, XDI: m-xylene diisocyanate, TDI:
tolylene diisocyanate, TPDI: 2,4-dithiapentane-1,3-diisocyanate
PETMP: pentaerythritol tetrakis(3-mercaptopropionate), XDT:
m-xylene dithiol, PETMA: pentaerythritol
tetrakis(2-mercaptoacetate)
[0119] The invention provides a polyisocyanate compound having a
aliphatic chain comprising sulfur atoms as a basic skeleton, in
which the refractive index and the Abbe number are high. It has
three isocyanate groups, and is easily polymerized with at least
one type of a compound having two or more hydroxyl groups in a
molecule, a compound having two or more mercapto groups in a
molecule and a compound having one or more hydroxyl groups and one
or more mercapto groups in a molecule to provide a
three-dimensionally crosslinked optical material. Since the optical
material obtained by using this polyisocyanate compound contains
the sulfur atoms in the main chain and is further crosslinked, the
refractive index and the Abbe number are high, the weatherability,
the solvent resistance and the transparency are excellent, and no
optical distortion is observed. The optical material is preferably
used in optical products, for example, lenses such as a spectacle
lens, a camera lens and the like, a prism, optical fibers,
substrates for recording medium used in an optical disk, a magnetic
disk and the like, a filter and the like. It can also be used in
ornamental products such as a glass, a vase and the like which are
obtained by making the most of the property of the high refractive
index.
[0120] The descriptions presented herein enable a person of
ordinary skill in the art to make and use the invention. Although
the invention has been fully described by way of examples with
reference to the accompanying drawings, it is to be noted that
various modifications will be readily apparent to those skilled in
the art, and the generic principles defined herein may be applied
to other embodiments and applications without departing from the
spirit and scope of the invention. Thus, the invention is not
intended to be limited to the embodiments shown, but is to be
accorded the widest scope consistent with the principles and
features disclosed herein.
* * * * *