SPECIFICATION
METHOD FOR PRODUCING POLYTHIOL COMPOUND, POLYMERIZABLE COMPOSITION
FOR OPTICAL MATERIAL, AND USES THEREOF
5
TECHNICAL FIELD
[OOOl]
The present invention relates to a method for producing a
polythiol compound, a polymerizable composition for optical
10 materials, and uses thereof.
BACKGROUND ART
[0002]
Plastic lenses are lightweight, not easily breakable and
tintable as compared with inorganic lenses. Therefore, in recent
15 years, plastic lenses have rapidlybeeninriideuseinopticaldevices
such as spectacle lenses and camera lenses.
[0003]
It has become necessary for resins for plastic lenses to have
more enhanced performances, and there have been demands for an
20 increase in the refractive index, an increase in the Abbe number,
a decrease in specific gravity, an increase in heat resistance, and
the like. Thus, a variety resin materials for lenses have been
hitherto developed and used.
[0004]
2 5 Among others, optical materials formed from
polythiourethane-based resins have high refractive index and high
Abbe numbers, and are excellent in impact resistance, tintability,
processability, and the like. Polythiourethane-based resins are
obtained by allowing polythiols to react with polyiso (thio) cyanate
compounds and the like.
[00031
5 It is required that in the case of being used in plastic lenses,
polythiourethane-based resins be less color, have excellent resin
colofs, and be transparent. If the quality of polythiol is poor,
the quality of the resin thus obtainable may also be poor.
The method for producing a polythiol is exemplified in the
10 following patent documents.
[00061
Patent Document 1 or 2 describes a method of obtaining a
particular polythiol compound by reacting 2-mercaptoethanol with
epichlorohydrin, reacting the compound thus obtained with thiourea
15 to obtain an isothiuronium salt, and then hydrolyzing the
isothiuronium salt.
[00071
Patent Document 3 describes a method for producing a polythiol
compound, the method including adjustinq the amount of particular
20 impuritiesthatare containedin2-mercaptoethanoltoapredetermined
range.
Patent Document 4 describes a method for producing a polythiol
compound, the method including adjusting the content of calcium that
is contained in thiourea to a predetermined range.
25 Patent Document 5 describes a method for producing a polythiol
compound, the method including adjusting the content of calcium that
is contained in thiourea, and the amount of particular impurities
that are contained in 2-mercaptoethanol, to predetermined ranges.
RELATED DOCUMENT
PATENT DOCUMENT
[00081
5 [Patent Document I] JapaneseUnexamined Patent PublicationNo.
2-270859
[Patent Document21 Japanese Unexamined Patent PublicationNo.
7-252207
[Patent Document 31 Pamphlet of International Publication No.
10 WO 2007/129449
[Patent Document 41 Pamphlet of International Publication No.
WO 2007/129450
[PatentDocument51 Korean Patent PublicationNo. 2010-0078120
15 DISCLOSURE OF THE INVENTION
[00091
However, in the case where a plastic lens formed from a
polythlourethane-based resin is produced using a polythiol compound
that is obtainable by the methods described these documents, there
20 is room for an improvement in quality such as color, transparency
and striation.
[00101
There have been cases, in which even if there is no problem in
theproductqualitywhena plastic lens isproducedusing apolythiol
25 compound obtained by small-scale production, the quality of the
polythiol compound fluctuates between different production batches
when a polythiol compound is produced cont~nuously and repeatedly
in the production i n an actual i n d u s t r i a l s c a l e . Furthermore, there
have been occasions in which when a p l a s t i c lens is produced using
such a polythiol compound, a p l a s t i c lens having a problem in quality
such as color, transparency and o p t i c a l homogeneity is obtained.
5 That i s , the efficiency percentage (number of items of quality
product/totalnumberofproduceditems) whichincludesplasticlenses
t h a t s a t i s f y the product quality described above among the p l a s t i c
lenses obtainable from a polythiol compound, has decreased i n some
cases.
10 [OOll]
However, there havebeen occasions inwhich defectivepolythiol
compounds occur i n large q u a n t i t ~ e sw ithout its cause being
understood. Furthermore, t h e r e h a v e b e e n a n i s s u e t h a t anevaluation
of t h e q u a l i t y of a polythiol compound as a monomer is d i f f i c u l t ,
15 based on the chemical analysis r e s u l t s of the polythiol compound,
and judgment must be made based on the evaluation of a p l a s t i c lens
t h a t can be actually obtained from the polythiol compound. A
polythiolcompoundwithwhich a p l a s t i c lens having a desiredproduct
quality cannot be obtained in i n d u s t r i a l production, cannot be used
20 as a monomer. Therefore, it is very important, in view of the
i n d u s t r i a l production efficiency of the polythiol compound and in
view of economic efficiency, t o e s t a b l i s h a method for producing a
polythiol compound by which a p l a s t i c lens product having a desired
product quality can be stably obtained.
25 [0012]
It is because a p l a s t i c lens formed from a thiourethane resin
is produced a t a r a t e of one sheet of lens per batch. Specifically,
f i r s t , a thiourethane-based polymerizable composition is i n j e c t e d
i n t o a glass type mold, the polymerizable composition is polymerized
under heating to cure, and then the cured product is released from
the glass type mold. Thus, one sheet of lens is produced. That is,
5 in order t o obtain one sheet of a thiourethane-based p l a s t i c lens,
many processes and operations are needed. Furthermore, i f a
thiourethane-based p l a s t i c lens is not proved t o have a desired
product quality, it i s d i f f i c u l t t o reuse the p l a s t i c lens as a
thiourethane resin, unlike those products formed fromthermoplastic
10 resins and t h e l i k e . Therefore, it is very important t o e s t a b l i s h
a method for producing a polythiol compound by which a p l a s t i c lens
product having a desired product quality is stably obtained, i n view
o f t h e i n d u s t r i a l production e f f i c i e n c y o f p l a s t i c lenses and i n view
of economic efficiency.
15 [0013]
Therefore, i n t h e case of continuously and repeatedlyproducing
a polythiol compound on an i n d u s t r i a l scale, it is necessary t o
e s t a b l i s h a method forproducing apolythiolcompoundwith excellent
production s t a b i l i t y , by which a polythiol compound t h a t is used as
20 a raw material for p l a s t i c lenses having a desired product quality
canbestablyobtained, without any f l u c t u a t i o n i n t h e p r o d u c t q u a l i t y
of the polythiol compound between d i f f e r e n t production batches.
[0014]
The present invention can be described as follows.
[ I ] A method for producing a polythiol compound, comprising:
a step for reacting 2-mercaptoethanol with an epihalohydrin
compoundrepresentedbythe following formula (1) toobtainacornpound
represented by the following formula (3) ;
(wherein X represents a halogen atom)
5 a step for reactingthe compound representedby formula (3) with
sodium sulfide to obtain a polyalcohol compound represented by the
following formula (4) ;
a step for reacting the polyalcohol compound represented by
10 formula (4) thus obtained with thiourea in the presence of hydrogen
chloride to obtain an isothiuronium salt;
a step for adding, while maintaining a reaction solution
containing an isothiuronium salt thus obtained at a temperature of
20°C to 6 0 ° C , aqueous ammonia to the reaction solution within 80
minutes to hydrolyze the isothiuronium salt to obtain a polythiol
compound containing one kind or trio or more kinds selected from the
group consisting of compounds represented by the folloriing formulae
(6) to (8) as a main component; and
a step for adding hydrochloric acid which is a concentration
of 30% to 36% to a solution containing the polythiol compound thus
obtained, washing the solution at a temperature of 30°C to 55OC to
purify the polythiol compound.
[2] The method for producing a polythiol compound according to
[I], wherein in the step for reacting 2-mercaptoethanol with an
epihalohydrin compound comprises:
a step for reacting 2-mercaptoethanol with the epihalohydrin
compound represented by formula (1) at a temperature of Z°C to 30°C.
[3] Amethodfor industrialmanufacture of apolythiolcompound,
using the production method according t o [ I ] or 121.
[ 4 ] A polymerizable composition f o r o p t i c a l materials,
containing a polythiol compound obtained by the production method
5 according t o any one of [ I ] to [3].
[5] A molded product obtained by curing the polymerizable
composition for o p t i c a l materials according t o 1 4 1 .
[6] A p l a s t i c lens formed from the molded product according to
[51.
10 [0015]
In addition, washing according t o the invention means a process
of s t i r r i n g andmixing an organic layer containing a product inwater
or an aqueous acid or a l k a l i solution, causing the mixture t o stand
s t i l l , subsequently separating the mixture t o liquid-liquid
15 p a r t i t i o n , and thus obtaining an organic layer containing a reaction
product. Waterwashingmeanswashingusingwater, acidwashingmeans
washing using an a c i d i c aqueous solution, and a l k a l i (aqueous
ammonia) washing means washing using an aqueous a l k a l i solution
(aqueous ammonia) .
20 [0016]
When a polythiol compound t h a t is obtainable from the method
forproducingapolythiolcompoundoftheinventionis used, a p l a s t i c
lens formed from a polythiourethane-based resin having excellent
quality such as color, transparency and s t r i a t i o n can be obtained.
25 Furthermore, according t o the invention, even i n the case where a
polythiol compound is produced repeatedly in actual production on
an i n d u s t r i a l scale, no fluctuation occurs i n the product quality
of the polythiol compound between different production batches, a
plastic lens having a desiredproduct qualitycanbe stablyobtained,
and a production method for a polythiol compound with excellent
production stability can be provided. Furthermore, a polythiol
5 compound which is suitable as a raw material for plastic lenses can
be stably supplied. Furthermore, when a polythiolcompound obtained
by such a method is used, the product yield and the efficiency
percentage of the product thus obtainable can be improved.
10 DESCRIPTION OF EMBODIMENTS
[00171
The "methodforproducingpolythiolcompoundsincludingone kind
or two or more kinds selected from the group consisting of
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane,
15 4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as a
main component (hereinafter, simply a polythiol compound)" of the
invention will be described based on the following exemplary
embodiment.
20 The method for producing a polythiol compound of the present
exemplary embodiment can include the steps described below.
Step A: 2-mercaptoethanol is reacted with an epihalohydrin
compound represented by the following formula (I), and thus a
polyalcohol compound represented by the following formula (3) is
25 obtained.
[00181
(wherein X r e p r e s e n t s a halogen atom)
[0019]
StepB: Thecompoundrepresentedby formula ( 3 ) o b t a i n e d i n s t e p
A is r e a c t e d with sodium s u l f i d e , and thus a polyalcohol compound
represented by the following formula ( 4 ) is obtained.
[0021]
H"-S - OH
H o l s J z H
10
[0022]
Step C: The polyalcohol compound represented by formula ( 4 )
o b t a i n e d i n s t e p B i s r e a c t e d w i t h t h i o u r e a i n t h e p r e s e n c e o f h y d r o g e n
c h l o r i d e , and thus an isothiuronium s a l t is obtained.
Step D: While a reaction solution containing the isothiuronium
salt obtained in step C is maintained at a temperature of 20°C to
60°C, aqueous ammonia is added to the reaction solution within 80
minutes, the isothiuronium salt is hydrolyzed, and thus a polythiol
5 compound is obtained.
Step E: Hydrochloric acid which is a concentration of 30% to
36% is addedto a solutioncontainingthepolythiolcompoundobtained
in step D, and the solution is washed at a temperature of 30°C to
55OC.
10 [00231
According to the production method of the present exemplary
embodiment, aplasticlens formedfromapolythiourethane-basedresin
produced using a polythiol compound that is obtained by performing
step D and step E in particular within the scope of the invention,
15 has excellent quality such as color, transparency and striation.
Furthermore, according to the production method of the present
exemplary embodiment, even in the case where a polythiol compound
is repeatedly produced in actual production on an industrial scale,
a polythiol compound having a desired product quality can be stably
20 obtained without any fluctuation in the product quality of the
polythiol compound between different production batches, and the
production stability is excellent. The production method of the
present exemplary embodiment is particularly useful as a method for
industrial manufacture of a polythiol compound.
25 Hereinafter, the various processes will be describedin order.
[00241
(Step A)
In the present exemplary embodiment, first, 2-mercaptoethanol
is reacted with an epihalohydrin compound represented by the
folloriing formula (I), and thereby a diol compound represented by
the folloriing formula ( 3 ) can be obtained.
5 [0025]
[0027]
In the formula (I), X represents a halogen atom which may be
a fluorine atom, a chlorine atom, a bromine atom or an iodine atom,
and is preferably a chlorine atom.
100281
Inthepresentexemplaryembodiment, the reactioncanbe carried
15 out at a temperature in the range of 2OC to 30°C, preferably 5OC to
20°C, and more preferably 5'C to 15OC. The reaction can be carried
out for 2 hours to 10 hours. When these processes are carried out
in the temperature ranges described above, the plastic lens thus
obtainable has excellent quality and an excellent product yield, and
the efficiency percentage is improved.
[00291
The method can be carried out s p e c i f i c a l l y in the following
5 manner.
F i r s t , an epihalohydrin is added dropwise i n t o
2-mercaptoethanol and i f necessary, an aqueous solution, or a lower
alcohol such as methanol or ethanol and a c a t a l y t i c amount of a base
inanaqueous solutionorloweralcoholsolutionofmethanolorethanol.
10 The reaction temperature and the reaction time are preferably
adjusted t o be i n the ranges described above. The use amount of
2-mercaptoethanolinthe s o l u t i o n t o w h i c h t h e epihalohydrinis added
dropriise is equal t o or more than 0.5 moles and equal t o or l e s s than
3 moles, preferably equal t o or more than 0.7 moles and equal t o or
15 less than 2 moles, andmorepreferablyequalto ormore than 0.9 moles
and equal t o or l e s s than 1.1 moles, r e l a t i v e t o 1 mole of the
epihalohydrin. Furthermore, a c a t a l y t i c amount of the base is used,
and the use amount of the base is, in the case of a monovalent base,
preferably equal t o or more than 0.001 moles and equal to o r l e s s
20 than 0.1 moles with respect to the epihalohydrin. In the case of
a divalent base, the use amount is preferably an amount equivalent
to a half the use amount of the monovalent base. The base can be
used as an aqueous solution, an alcohol solution or t h e l i k e , and
when the base is used as a solution, the concentration of the base
25 canbeappropriatelyselected. As anepihalohydrinis addeddropwise
t o the solution, a d i o l compound represented by formula ( 3 ) 1s
obtained.
[0030]
(Step B)
Next, the diol compound represented by formula (3) obtained i n
step A is reacted with sodium s u l f i d e , and thus a tetra01 compound
5 represented by the following formula ( 4 ) can be obtained.
[0031]
[a0321
Inthepresentexempiaryembodiment, t h e r e a c t i o n c a n b e carried
10 out a t a temperature i n the range of 10°C to 50°C, and preferably
20°C t o 40°C. The reaction can be carried out for 1 hour t o 10 hours.
Whenthe reactioniscarriedoutundertheconditionsdescribedabove,
the p l a s t i c lens thus obtainable has excellent quality and an
excellent product yield, and the efficiency percentage is improved.
15 [0033]
The reaction can be carried out s p e c i f i c a l l y as follows.
Anaqueoussolutionofsodiumsulfideisaddeddropblise, o r s o l i d
sodium s u l f i d e is charged, i n t o the r e a c t i o n s o l u t i o n containing the
diol compoundobtained a f t e r the reaction. The reaction temperature
20 and the reaction time are preferably adjusted t o be i n the ranges
describedabove. Sodiumsulfide c a n b e u s e d i n a n a m o u n t o f 0 . 4 m o l e s
t o 0.6moles, preferably0.45molesto 0.57moles, andmore preferably
0.48 moles t o 0.55 moles, r e l a t i v e t o 1 mole of the d i o l compound.
[00341
(Step C)
Next, the tetraol compound represented by formula (4) that has
been obtained in step B is reacted with thiourea in the presence of
5 hydrogen chloride, and thus an isothiuronium salt is obtained.
[00351
Specifically, thiourea is added to the tetraol compound in an
amount of 3 moles or more, preferably equal to or more than 3 moles
and equal to or less than 6 moles, and more preferably equal to or
10 more than 4.6 moles and equal to or less than 5.0 moles, relative
to 1mole ofthetetraolcompound, andthus the components are reacted
with each other. The reaction is carried out in the presence of
hydrogen chloride in an amount of 3 moles or more, and preferably
equal to or more than 3 moles and equal to or less than 12 moles,
15 relative to 1 mole of the tetraol compound, at a temperature in the
range of from room temperature to the reflux temperature, and
preferably 90°C to 120°C, for about 1 hour to 10 hours. An
isothiuronium salt compound is formed by the reaction between a
tetraol compound and thiourea. When hydrogen chloride is used, a
20 sufficient rate of reaction is obtained, and also, coloration ofthe
thiol compound and the color of the plastic lens thus obtainable can
be controlled. Regarding the hydrogen chloride, anaqueous solution
of hydrochloric acid or hydrogen chloride gas can be used.
[0036]
25 (Step D)
Aqueous ammonla is added to a reaction solution containing the
lsothiuronium salt obtained in step C, and the isothiuronium salt
is hydrolyzed. Thus, a polythiol compound is obtained.
In the present exemplary embodiment, a polythiol compound
containing, as amaincomponent, one kindortwo ormore kinds selected
from the group consisting of
5 4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane
represented by the following formula (6),
4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane
represented by the following formula (7), and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane
10 represented by the following formula (8) can be obtained.
[0037]
[Chemical Formula 111
[00381
Specifically, while a r e a c t i o n s o l u t i o n containing the
isothiuronium s a l t is maintained a t a temperature in the range of
20°C to 60°C, preferably 25OC t o 55OC, and more preferably 25'C t o
5 50°C, aqueous ammoniais addedtothe r e a c t i o n s o l u t i o n for 80minutes
or l e s s , preferably 70 minutes or less, more preferably 20 minutes
t o 60 minutes, and even more preferably 20 minutes t o 30 minutes.
It is preferable i f the time for which aqueous ammonia is added is
shorter, but i n view of the capacity of the f a c i l i t i e s such a s t h e
10 cooling capacity, the time is set t o the range of the time period
described above.
Whena h y d r o l y t i c r e a c t i o n i s carriedoutunder suchconditions,
p l a s t i c lenses formed from a polythiourethane-based resin having
excellent quality such as color, transparency and s t r i a t i o n can be
tainedwith a stabilizedproductqua
can be improved.
[00391
Itispreferabletoaddanorganicsolventbeforeaqueousamonia
isadded. Whenanorganicsolventisadded, productionofby-products
20 can be suppressed. The amount of the organic solvent added is
appropriately selected depending on the kind of the solvent or the
l i k e , however the organic solvent can be added in an amount of 0 . 1
t o 3.0 times, and preferably 0.2 t o 2.0 times, the amount of the
thiuronium s a l t r e a c t i o n s o l u t i o n . Examples of the organic solvent
25 include toluene, xylene, chlorobenzene, and dichlorobenzene. From
the viewpoint of the e f f e c t s described above, toluene is preferred.
[00401
Aqueous ammonia canbe addedinan amount of, in terms of ammonia
(NH3), 1 mole or more, preferably equal to or more than 1 mole and
equal to or less than 3 moles, and more preferably equal to or more
than 1.1 moles and equal to or less than 2 moles, relative to 1 mole
5 of the use amount of hydrogen chloride described above, within the
addition time describedabove. The concentration of aqueous ammonia
can be adjusted to 10% to 25%. Furthermore, ammonia gas can also
be used instead of aqueous ammonia.
Inthe caseofaddingammoniagasinsubstitutionofthe entirety
10 or aportion of aqueous ammonia, the reaction canbe carriedoutunder
the same conditions (use amount, addition time, and addition
temperature) as those in a case where aqueous ammonia is used.
[00411
In the present exemplary embodiment, ammonia (NH3) is added at
15 a rate of addition of 1.25 mol%/min or more, preferably equal to or
more than 1.25 mol%/min and equal to or less than 3.75 mol%/min, and
more preferably equal to or more than 1.38 mol%/min and equal to or
less than 2.5 mol%/min, relative to 1 mole of hydrogen chloride. In
the present process, it is not necessary to add ammonia continuously
20 at the above-described rate, and it is acceptable if the average rate
of addition of the addition time described above is included in this
range.
After aqueous ammonia is added, the hydrolytic reaction is
carried out continuously at a temperature in the range of from room
25 temperature to the reflux temperature, and preferably 30°C to 80°C,
for about 1 hour to 8 hours.
[00421
In the present exemplary embodiment, the polythiol compound
obtained in step D is purified.
Specifically, acid washing and then several t i m e s of water
5 washing can be carried out. Water washing can also be carried out
before acidwashing, a n d a l k a l i washing c a n a l s o b e c a r r i e d o u t a f t e r
acid washing. The number of water washing can be reduced by a l k a l i
washing. Impurities and the l i k e can be e f f i c i e n t l y removed by the
washing process. When p u r i f i c a t i o n by such washing is performed,
10 the color o f t h e p l a s t i c lenses obtained fromthe p o l y t h i o l compound
is improved, and high quality p l a s t i c lenses with reduced occurrence
of clouding and s t r i a t i o n can be produced with a high yield, while
the efficiency percentage is also improved. Examples of preferred
embodiments include a method of performing water washing-acid
15 washing-water washing-alkali washing-water washing a f t e r
hydrolysis; amethodofperformingacidwashing-waterrqashing-alkali
washing-water washing; and amethodofperforming acidwashing-water
washing. The respective washing processes may be repeated several
times.
20 I00431
Acid washing can be carried out by adding hydrochloric acid t o
the solution containing the polythiol compound thus obtained. The
concentration of hydrochloric acid can be adjusted t o 30% t o 36%.
When the concentration of hydrochloric acid is lower than 30%,
25 cloudingmayoccurintheplasticlensduetoimpurities andthe l i k e .
Furthermore, the temperature of acid washing can be s e t t o 30°C t o
55"C, preferably 30°Cto 45OC, more preferably 30°Cto 40°C, andeven
more preferably 31°C to 40°C.
When the concentration of hydrochloricacid andthe temperature
conditions are satisfied, plastic lenses having excellent color and
reduced clouding can be obtained with a high product yield, and the
5 efficiency percentage is also improved.
[00441
Water washing can be achieved by using degassed water having
an oxygen concentration of 5 mg/L or less.
Examples of the method for producing degassed water include a
10 method of purging dissolved oxygen by bubbling nitrogen; a method
of purging dissolved oxygen by a heating treatment; and a method of
purging dissolved oxygen by vacuum degassing. However, there are
no particular limitations on the method as long as the oxygen
concentration can be adjusted to 5 mg/L or less.
15 Thereby, color or clouding that causes a problem in optical
materials such as plastlc lenses can be effectively suppressed.
[00451
Furthermore, alkali washlng can be carried out by adding an
alkaline aqueous solution, and stirring the mixture at a temperature
20 in the range of 20°C to 50°C for 10 minutes to 3 hours. The alkaline
aqueous solution is preferably aqueous ammonia. Furthermore, the
concentrationofaqueousammonia canbe set to O.l%tolO%, preferably
0.1% to 1%, and more preferably 0.1% to 0.5%.
[00461
25 Also for acid washing and alkali washing, when water having an
oxygen concentration of 5 mg/L or less is used, color or clouding
that causes a problem in optical materials such as plastic lenses
can be effectively suppressed.
[0047]
After step E, a solvent removal process, and if necessary, a
lowboilingpoint-compound removal process, a filteringprocess, and
5 a distillation process are carriedout, andthus a polythiolcompound
containing, asamaincomponent, one kindortwoormore kinds selected
from the group consisting of
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane,
4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
10 5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane can be
obtained as a polythiol compound.
The solvent removal process is aprocess of removingthe organic
solvent at normal pressure or under reduced pressure. The degree
of pressure reduction and the temperature may be appropriately
15 selected depending on the solvent used or the like, however it is
preferable to carry out the solvent removal process under reduced
pressure and at 100°C or lower, and preferably 85°C or lower.
[0048]
The low boillng point-compound removal process is a process of
20 removing any included low boiling point compounds at normal pressure
or under reduced pressure, after the solvent removal process. The
degreeof pressure reductionandthe temperaturemaybe appropriately
selected depending on the solvent used or the like, however it is
preferable to carry out the low boiling point-compound removal
25 process under reduced pressure and at 100°C or lower, and preferably
85°C or lower. At that time, the process may also be carried out
while an inert gas such as nitrogen gas is blown in.
[00491
The filtering process is a process of removing solids such as
salts by filtration. The method for filtration or the like is
appropriately selected, for example filtration under reduced
5 pressure or filtration under added pressure using a membrane filter
or a cartridge filter can be used. It is preferable to carry out
the process using a filter having a pore size of 5 pm or less, and
preferably 2 pm or less.
[00501
10 Thedistillation process is aprocess ofpurifyingthepolythiol
compound by distillation. The degree of pressure reduction and the
temperature may be appropriately selected depending on the solvent
used or the like, however it is preferable to carry out the
distillation process under reduced pressure and at 250°C or lower,
15 and preferably 200°C or lower.
In addition, the production process of the present exemplary
embodiment can be carried out in air, but it is preferable to carry
out the entire process in a nitrogen atmosphere, from the viewpoint
of color.
20 [00511

The polymerizable composition for optical materials according
to the present exemplary embodiment includes a polythiol compound
for optical materials obtained by the method described above, and
25 a polyiso(thio)cyanate compound.
[00521
The polyiso (thio) cyanate compound is not particularly limited
aslongasitisacompoundhavingatleasttr~oormoreiso(thio)cyanate
groups in one molecule, and specific examples include aliphatic
polyisocyanate compounds such as hexamethylene diisocyanate,
1,5-pentane diisocyanate, 2,2-dimethylpentane diisocyanate,
5 2,2,4-trimethylhexane diisocyanate, butene diisocyanate,
1,3-butadiene-1,4-diisocyanate, 2,4,4-trimethylhexamethylene
diisocyanate, 1,6,1l-undecane triisocyanate, 1,3,6-hexamethylene
triisocyanate, 1,8-diisocyanato-4-isocyanatomethyloctane,
bis (isocyanatoethyl) carbonate, bis (isocyanatoethyl) ether, lysine
10 diisocyanate methyl ester, and lysine triisocyanate;
alicyclic polyisocyanate compounds such as isophorone
diisocyanate, bis(isocyanatomethyl)cyclohexane,
dicyclohexylmethane diisocyanate, cyclohexane diisocyanate,
methylcyclohexane diisocyanate, dicyclohexyl dimethylmethane
15 isocyanate, 2,5-bis (isocyanatomethyl)- bicycle 12.2.11 heptane,
2,6-bis(isocyanatomethy1)-bicyclo[2.2.1]heptane,
3,8-bis(isocyanatomethyl)tricyclodecane,
3,9-bis (isocyanatomethyl)t ricyclodecane,
4,8-bis(isocyanatomethyl)tricyclodecane,
20 4,9-bis(isocyanatomethyl)tricyclodecane,
bis(4-isocyanatocyclohexyl)methane,
1,3-bis (isocyanatomethyl) cyclohexane, and
1,4-bis (isocyanatomethyl) cyclohexane;
polyisocyanate compounds having aromatic ring compounds, such
25 as 1,2-diisocyanatobenzene, 1,3-diisocyanatobenzene,
1,4-diisocyanatobenzene, tolylene diisocyanate,
2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, ethylphenylene
diisocyanate, isopropylphenylene diisocyanate, dimethylphenylene
diisocyanate, diethylphenylene diisocyanate, diisopropylphenylene
diisocyanate, trimethylbenzene triisocyanate, benzene
triisocyanate, biphenyl diisocyanate, toluidine diisocyanate,
5 4,4'-methylenebis(pheny1 isocyanate),
4,4'-methylenebis(2-methylphenyl isocyanate),
bibenzyl-4,4' -diisocyanate, bis (isocyanatophenyl) ethylene,
bis(isocyanatomethyl)benzene, m-xylylene diisocyanate,
bis (isocyanatoethyl)b enzene, bis (isocyanatopropyl)b enzene, a,a ,a ',
10 a'-tetramethylxylylene diisocyanate, bis(isocyanatobutyl)benzene,
bis(isocyanatomethyl)naphthalene, bis(isocyanatomethylpheny1)
ether, bis (isocyanatoethyl) phthalate, and
2,5-di(isocyanatomethy1)furan;
sulfur-containing aliphatic polyisocyanate compounds such as
15 bis(isocyanatomethy1) sulfide, bis(isocyanatoethy1) sulfide,
bis(isocyanatopropy1) sulfide, bis(isocyanatohexy1) sulfide,
bis(isocyanatomethyl)sulfone, bis(isocyanatomethy1) disulfide,
bis(isocyanatoethy1) disulfide, bis(isocyanatopropy1) disulfide,
bis(isocyanatomethylthio)methane, bis(isocyanatoethylthio)methane,
20 bis(isocyanatomethylthio)ethane, bis(isocyanatoethylthio)ethane,
1,5-diisocyanato-2-isocyanatomethyl-3-thiapentane,
1,2,3-tris (isocyanatomethylthio)p ropane,
1,2,3-tris(isocyanatoethylthio)propane,
3,5-dithia-1,2,6,7-heptane tetraisocyanate,
25 2,6-diisocyanatomethyl-3,5-dithia-1,7-heptane diisocyanate,
2,5-diisocyanatomethylthiophene, and
4-isocyanatoethylthio-2,6-dithia-1,8-octane diisocyanate;
aromatic sulfide-based polyisocyanate compounds such as
2-isocyanatophenyl-4-isocyanatophenyl sulfide,
bis(4-isocyanatophenyl) sulfide, bis(4-isocyanatomethylphenyl)
sulfide;
5 aromatic disulfide-based polyisocyanate compounds such as
bis (4-isocyanatophenyl) disulfide,
bis(2-methyl-5-isocyanatophenyl) disulfide,
bis(3-methyl-5-isocyanatophenyl) disulfide,
bis(3-methyl-6-isocyanatophenyl) disulfide,
10 bis(4-methyl-5-isocyanatophenyl) disulfide, and
bis(4-methoxy-3-isocyanatophenyl) disulfide;
sulfur-containing alicyclic polyisocyanate compounds such as
2,5-diisocyanatotetrahydrothiophene,
2,5-diisocyanatomethyltetrahydrothiophene,
15 3,4-diisocyanatomethyltetrahydrothiophene,
2,5-diisocyanto-l,4-dithiane, 2,5-diisocyantomethyl-1,4-dithiane,
4,5-diisocynato-1,3-dithiolane,
4,5-bis(isocyantomethy1)-1,3-dithiolane, and
4,5-diisocyantomethyl-2-methyl-1,3-dithiolane;
2 0 aliphatic polyisothiocyanate compounds such as
1,2-diisothiocyanatoethane and 1,6-diisothiocyanatohexane;
alicyclic polyisothiocyanate compounds such as cyclohexane
diisothiocyanate;
aromatic polyisothiocyanate compounds such as
25 1,2-diisothiocyanatobenzene, 1,3-diisothiocyanatobenzene,
1,4-diisothiocyanatobenzene, 2,4-diisothiocyanatotoluene,
2,5-diisothiocyanato-m-xylene, 4,4'-methylenebis(pheny1
isothiocyanate), 4,4'-methylenebis(2-methylphenyl isothiocyanate),
4,4'-methylenebis(3-methylphenyl isothiocyanate),
4,4'-diisothiocyanatobenmphenom,
4,4'-diisothiocyanato-3,3'-dimethylbenzohenone and
5 bis(4-isothiocyanatophenyl) ether;
carbonyl polyisothiocyanate compounds such as 1,3-benzene
dicarbonyl diisothiocyanate, 1,4-benzene dicarbonyl
diisothiocyanate, and (2,2-pyridine)-4,4-dicarbonyl
diisothiocyanate;
10 sulfur-containing aliphatic polyisothiocyanate compounds such
as thiobis(3-isothiocyanatopropane),
thiobis(2-isothiocyanatoethane), and
dithiobis(2-isothiocyanatoethane);
sulfur-containing aromatic polyisothiocyanate compounds such
15 as l-isothiocyanato-4-[(2-isothiocyanato)sulfonyl]benzene,
thiobis(4-isothiocyanatobenzene),
sulfonyl(4-isothiocyanatobenzene), and
dithiobis(4-isothiocyanatobenzene);
sulfur-containing alicyclic polyisothiocyanate compounds such
20 as 2,5-diisothiocyanatothiophene and
2,5-diisothiocyanato-1,4-dithiane; and
compounds having isocyanato groups and isothiocyanato groups,
such as 1-isocyanato-6-isothiocyanatohexane,
1-isocyanato-4-isothiocyanatocyclohexane,
25 1-isocyanato-4-isothiocyanatobenzene,
4-methyl-3-isocyanato-1-isothiocyanatobenzene,
2-isocyanato-4,6-diisothiocyanato-1,3,5-triazine,
4-isocyanatophenyl-4-isothiocyanatophenyl sulfide, and
2-isocyanatoethyl-2-isothiocyanatoethyl disulfide.
[0053]
Preferredexamples ofthepolyiso(thio)cyanatecompoundinclude
5 aliphatic polyisocyanate compounds such as hexamethylene
diisocyanate, 1,5-pentane diisocyanate, isophorone diisocyanate,
bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane
diisocyanate, 2,5-b~s(isocyanatomethy1)-bicyclo[2.2.1]heptane,
2,6-bls (isocyanatomethyl) -bicyclo[2.2.1] heptane,
10 bis(4-isocyanatocyclohexyl)methane,
1,3-bis(isocyanatomethyl)cyclohexane, and
1,4-bis(isocyanatomethyl)cyclohexane; andpolyisocyanate compounds
havingaromaticringcompounds, suchasbis(isocyanatomethyl)benzene,
m-xylylene diisocyanate, 1,3-diisocyanatobenzene, tolylene
15 diisocyanate, 2,4-dlisocyanatotoluene, 2,6-diisocyanatotoluene,
4,4'-methylenebis(pheny1 isocyanate).
[0054]
Furthermore, halogen-substituted forms such as
chlorine-substituted forms and bromine-substituted forms,
20 alkyl-substituted forms, alkoxy-substituted forms,
nitro-substituted forms, prepolymer type modified forms associated
with polyhydric alcohols, carbodiimide-modified forms,
urea-modified forms, biuret-modified forms, dimerized ortrimerized
reaction products and the like of those compounds described above
25 can also be used. These compounds may be used alone, or mixtures
of two or more kinds may be used.
[0055]
Regarding the polythiol compound used in the polymerizable
composition for optical materials, other polythiol compounds for
optical materials can also be used in addition to the polythiol
compounds for optical materials obtained by the method described
5 above.
Preferred examples of the otherpolythiolcompounds for optical
materials include aliphatic polythiol compounds such as
methanedithiol, 1,2-ethanedithiol, 1,2,3-propanetrithiol,
pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol
10 tetrakis(3-mercaptopropionate), bis(mercaptoethy1) sulfide,
4-mercaptomethyl-l,8-dimercapto-3,6-dithiaoctane,
2,5-dimercaptomethyl-1,4-dithiane,
tetrakis(mercaptomethylthiomethyl)methane,
tetrakis (2-mercaptoethylthiomethyl)methane,
15 tetrakis (3-mercaptopropylthiomethyl)methane,
bis(2,3-dimercaptopropyl) sulfide,
2,5-dimercaptomethyl-1,4-dithiane, 2,5-dimercapto-1,4-dithiane,
2,5-dimercaptomethyl-2,5-dimethyl-1,4-dithiane,
1,1,3,3-tetrakis(mercaptomethylthio)propane,
20 1, l,2,2-tetrakis (mercaptomethylthio)e thane, and
4,6-bis(mercaptomethy1thio)-1,3-dithiane.
[00561
The use ratio of the polythiol compound and the
polyiso (thio) cyanate compound is not particularly limited, however
25 usually, the molar ratio of SH group/NCO group is in the range of
0.5to 3.0, preferably in the range of 0.6to 2.0, andmore preferably
intherangeof0.8tol.3. Whentheuseratiois intherangedescribed
above, various performances such as the refractive index and heat
resistance that are required in optical materials such as plastic
lenses and transparent materials can be satisfied in a well-balanced
manner.
5 [0057]
For the purpose of improving various properties, operability
and polymerization reactivity of the polythiourethane-based resin
of the invention, other substances may be added in addition to the
polythiol compound and iso(thio)cyanate compound that form the
10 urethane resin. For example, in addition to the urethane-forming
raw materials, one kind or two or more kinds of active hydrogen
compounds represented by amine or the like, carbonate compounds,
estercompounds, metals, metaloxides, organometalliccompounds, and
inorganic substances may also be added.
15 [0058]
Furthermore, various substances suchas a chainextending agent,
a crosslinking agent, a photostabilizer, an ultraviolet absorber,
an oxidation inhibitor, an oil-soluble dye, a filler, and a mold
releasing agentmay alsobe addedaccordingtothepurpose, similarly
20 to known molding methods. In order to adjust the rate of reaction
to a desired value, thiocarbamic acid S-alkyl ester, or a known
reaction catalyst that is used in the production of
polythiourethane-based resins may also be appropriately added.
Regarding the reaction catalyst, thiocarbamic acid S-alkyl
25 ester, or a known reaction catalyst that is used in the production
of polythiourethane-based resins can be appropriately added.
Examples of the reaction catalyst include dialkyltin halides
suchas d i b u t y l t i n d i c h l o r i d e anddimethyltindichloride; d i a l k y l t i n
dicarboxylatessuchasdimethyltindiacetate, dibutyltindioctanoate,
and d i b u t y l t i n dilaurate; d i a l k y l t i n dialkoxides such as d i b u t y l t i n
dibutoxide and d i o c t y l t i n dibutoxide; d i a l k y l t i n dithioalkoxides
5 such as d i b u t y l t i n di(thiobut0xide); d i a l k y l t i n oxides such as
di(2-ethylhexy1)tin oxide, d i o c t y l t i n oxide, and
bis(butoxydibuty1tin) oxide; and d i a l k y l t i n s u l f i d e s such as
d i b u t y l t i n s u l f i d e . Suitable examples include d i a l k y l t i n halides
such as d i b u t y l t i n dichloride and dimethyltin dichloride.
10 [0059]
Furthermore, for the purpose of modifying the resin, r e s i n
modifying agents such as a hydroxyl compound, an epoxy compound, an
e p i s u l f i d e compound, an organic acid and an anhydride thereof, and
an o l e f i n compound containing a (meth) acrylate compound or the l i k e
15 may a l s o be added. Here, the r e s i n modifying agent is a compound
which r e g u l a t e s orenhancesproperties suchas r e f r a c t i v e index, Abbe
number, heatresistanceandspecificgravity, andmechanicalstrength
such as impact resistance of a material formed from a
thiourethane-based r e s i n .
20 [0060]
Furthermore, the polymerizable composition for o p t i c a l
materials of the present exemplary embodiment may include a bluing
agent as necessary. The bluing agent has an absorption band in the
wavelength range of from orange color t o yellow color i n the v i s i b l e
25 l i g h t region, andhas a f u n c t i o n o f r e g u l a t i n g t h e color of a n o p t i c a l
material formed from a resin. More s p e c i f i c a l l y , the bluing agent
contains a substance which displays from blue color t o v i o l e t color.
There are no p a r t i c u l a r limitations on the bluing agent t h a t
is used i n the polymerizable composition for o p t i c a l materials of
thepresentexemplaryembodiment, andspecificexamplesincludedyes,
5 fluorescent brightening agents, fluorescent pigments, and inorganic
pigments. The bluing agent is appropriately selected among those
t h a t can be used as bluing agents, i n accordance with the properties
required from o p t i c a l components, r e s i n color, and the l i k e . These
bluing agents may be used respectively alone, or two or more kinds
10 may be used in combination.
[0062]
Among these bluing agents, from the viewpoint of s o l u b i l i t y i n
the polymerizable composition and the viewpoint of transparency of
t h e o p t i c a l material thus obtainable, a dye is preferred.
From the viewpoint of the absorption wavelength, the bluing
agent is preferably a dye having a maximum absorption wavelength of
equal t o or more than 520 nm and equal to o r l e s s than 600 nm, and
morepreferablyadye havingamaximumabsorption~~avelenqthofequal
20 t o or more than 540 nm and equal t o o r l e s s than 580 nm.
Furthermore, fromthe viewpoint o f t h e s t r u c t u r e o f t h e compound,
an anthraquinone-based dye is preferred.
[0064]
There are no p a r t i c u l a r limitations on the method for adding
25 the bluing agent, and it is preferable t o have the bluing agent added
i n advance t o the monomer system. Regarding the method, various
methods suchas amethodofdissolvingthebluingagentinthemonomer,
and a method of preparing a master solution containing a high
concentration of the bluing agent, and adding the bluing agent by
dilutingthemastersolutionwiththemonomerusedoranotheradditive,
can be employed.
5 [a0651
Specifically, the polymerizable composition for optical
materials of the present exemplary embodiment is obtained as a mixed
solution, bymixingthepolythiolcompoundobtainedbytheproduction
method described above and a polyiso(thio)cyanate compound, with
10 other components as necessary. This mixed solution is subjected to
defoaming by an appropriate method according to necessity,
s u b s e q u e n t l y i n j e c t e d t h e m i x e d s o l u t i o n i n t o a m o l d , andpolymerized
byslowlyheatingusuallyfromalowtemperaturetoahightemperature.
[a0661
15 A molded product formed from the polythiourethane-based resin
obtainable by curing the polymerizable composition of the present
exemplary embodiment in this manner has features such as a high
refractive index, low dispersibility, excellent heat resistance and
durability, light weight, and excellent impact resistance. Also,
20 the molded product has satisfactory color, and is suitable as a raw
material for optical materials such as spectacle lenses and camera
lenses, and transparent materials.
[00671
Furthermore, a plastic lens obtained by using the
25 polythiourethane-basedresin of thepresentexemplaryembodimentmay
also be subjectedtophysicaland chemical treatments such as surface
polishing, antistatic treatment, hard coating treatment,
non-reflective coating treatment, staining treatment, and dimming
treatment, in order to perform improvements such as prevention of
reflection, impartation of high hardness, enhancement of abrasion
resistance, enhancement of chemical resistance, impartation of
5 anti-fogging, and impartation of fashionability.
EXAMPLES
[00681
Hereinafter, the present invention will be described in more
10 detail based on Examples, however the invention is not intended to
be limited to these.
[00691
In the following Examples, properties were measured by the
following measurement methods.
15 APHA: This is a method for indicating the color, and the color
was determinedusing standardliquidspreparedbydissolvingreagents
of platinum and cobalt, and determining a standard liquid dilution
having a color density equivalent to that of the color of the sample
by making a comparison. Thus, the "degree" of the color was defined
20 as the measured value.
Water content: A sample was dissolved in toluene, and water
measurement was carried out using a Karl-Fischer Water Titrate.
Viscosity: The viscosity was measured according to JIS K7117.
Refractive index: The refractive index was measured at 20°C
25 using a digital refractometer, RI-600, manufactured by Kyoto
Electronics Manufacturing Co., Ltd.
Ammonium content: The sample was dissolved in chloroform and
extracted with water, and the ammonium content tias measured by ion
chromatography.
Acidcontent: Thesamplewasdissolvedinasolvent, thesolvent
was t i t r a t e d using a methanol solution of KOH, and the acid content
5 was calculated as a HCI content.
Lossdegreeoftranspareancyofresin:A9-mmplateriasproduced
under the conditions f o r t h e p l a s t i c lens productionofthe Examples,
and t h e l o s s degree of transpareancy was measured using a loss degree
oftranspareancyanalyzer (manufacturedbyHayashiCo., Ltd.;LUMINAR
10 ACE LA-150SE) .analyzer.
Resin Y I : This is a yellow index for color evaluation, and
is measured with a colorimeter. A 9-mm p l a t e was produced under the
conditions for the p l a s t i c lens production of the Examples, and the
Y I value was measured using a colorimeter (CR-400) manufactured by
15 Konica Minolta, Inc.
S t r i a t i o n : A lens was produced under the conditions for the
p l a s t i c lens production of the Examples, and the lens was visually
observed under a high pressure mercury lamp. A sample i n which no
s t r i p e d pattern was observed was rated as 0, and a sample in which
20 a s t r i p e d pattern was observed was rated as X.
[0070]
Furthermore, degassed~iateratadissolvedoxygenconcentration
of 2 ppm was obtained by bubbling nitrogen i n t o water and thereby
purging dissolved oxygen.
25 [0071]
[Example C-l]
(Synthesis of polythiol compound containing
bis(mercaptomethyl)-3,6,9-trithia-l,ll-undecanedithiol a s a main
component)
In a r e a c t o r , 51.2 p a r t s by weight of 2-mercaptoethanol, 26.5
p a r t s by weight of degassed water (dissolved oxygen c o n c e n t r a t i o n :
5 2ppm), a n d 0 . 1 6 p a r t s b y w e i g h t o f a 49wt% aqueous s o l u t i o n o f sodium
hydroxidewereintroduced. 61.99 p a r t s byweight of epichlorohydrin
was added dropwise t h e r e t o over 6.5 hours a t 9OC t o ll°C.
Subsequently, t h e mixture was s t i r r e d f o r 60 minutes. Production
of 1-chloro-3-(2-hydroxyethy1thio)-2-propano was confirmed from
10 NMR d a t a .
Subsequently, 150.0 p a r t s by weight of a 17.3% aqueous s o l u t i o n
of sodium s u l f i d e was added dropwise over 5.5 hours a t 7OC t o 37OC,
and t h e mixture was s t i r r e d f o r 120 minutes. Production of a tetra01
compound of formula ( 4 ) was confirmed from NMR d a t a . 279.0 p a r t s
15 by weight of 35.5% hydrochloric a c i d was introduced, and then 125.8
p a r t s byweight of t h i o u r e a having a p u r i t y o f 99.90% was i n t r o d u c e d .
Themixturewas s t i r r e d f o r 3 hours u n d e r r e f l u x a t l l O ° C , a n d t h e r e b y
a r e a c t i o n w h i c h formsthiuroniurnsaltrias c a r r i e d o u t . The r e a c t i o n
mixture was cooled t o 45OC, and then 214.0 p a r t s by weight of toluene
20 was added t h e r e t o , and the mixture was cooled t o 26OC. 206.2 p a r t s
by weight of a 25 wt% aqueous ammonia s o l u t i o n was i n t r o d u c e d o v e r
30 minutes at 26OC t o 50°C, and a h y d r o l y t i c r e a c t i o n was c a r r i e d
o u t b y s t i r r i n g t h e m i x t u r e f o r 1 h o u r a t 5 0 ° C t o 65OC. Thus, a t o l u e n e
s o l u t i o n of a p o l y t h i o l containing
25 4-mercaptomethyl-l,8-dimercapto-3,6-dithiaoctane as a main
component was obtained. 59.4 p a r t s by weight of 36% hydrochloric
acidwas addedtothetoluenesolution, andacidwashing f o r 30minutes
at 34OC to 3g°C was performed two times. 118.7 parts by weight of
degassed water (dissolved oxygen concentration: 2 ppm) was added,
and washing for 30 minutes at 35OC to 45OC was performed five times.
Toluene and a trace amount of water were removed under heating at
5 reduced pressure, and then the residue was filtered under reduced
pressure using a 1.2 vm PTFE type membrane filter, and thus 115.9
parts by weight of a polythiol compound containing
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane
(hereinafter, compound A) ,
10 4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane
(hereinafter, compound B) , and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane
(hereinafter, compound C) as main components was obtained (isomeric
mixture of compoundsA/B/C= 85/5/10 (molar ratio)). The properties
15 of the polythiol compound thus obtained are shown in Table-1.
(Measurement of viscosity of polymerizable composition)
50.7 parts by weight of m-xylylene diisocyanate, 0.015 parts
by weight of dibutyltin dichloride as a curing catalyst, 0.10 parts
by weight of ZELEC UN (trade name, product of Stepan Company; acidic
20 phosphoric acid ester), and 0.05 parts by weight of BIOSORB 583
(manufactured by Kyodo chemical Co., Ltd.; ultraviolet absorbent)
were mixed and dissolved at 20°C. 49.3 parts by weight of the
polythiol compound containing
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane,
25 4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as
main components thus obtained was introduced and mixed, and thus a
mixed uniform solution was obtained. The time of preparation of the
mixed uniform solution was defined as 0 Hr, and the viscosity after
7 hours was measured with a B type viscometer. The viscosity after
7 hours of the polymerizable composition was used as an index of the
5 rate of polymerization. An evaluation was conducted such that a
sample having a viscosity value of 250 mPa.s or less was rated as
0, and a sample having a viscosity value of 1000 mPa.s or more was
rated as X. The results are shown in Table-2.
100721
10 Thepolythiolcomposedoftheseisomerswas subjectedto reverse
phase chromatography to isolate the respective components, and
identification was performed. First, the results of an elemental
analysis, IR, MS and NMR of the compound A will be shown.
[0073]
[0074]
2543 (SH)
m/z = 366 (M')
[0075]
15
.
C
H
S
Measured value (%)
32.7
6.2
61.1
Calculated value (%)
32.8
6.1
61.2
< I3 C-NMR CDCh >
Next, the results of NMR of the compound C will be shown. The
results of an elemental analysis, IR and MS were the same as those
5 of the compound A.
Finally, the results of NMR of the compound B will be shown.
10 The results of an elemental analysis, IR and MS were the same as those
of the compound A.
(Production of plastic lens)
50.7 parts by weight of m-xylylene diisocyanate, 0.01 parts by
5 weight of dibutyltin dichloride as a curing catalyst, 0.10 parts by
weight of ZELEC UN (trade name, product of Stepan Company; acidic
phosphoric acid ester), and 0.05 parts by weight of BIOSORB 583
(manufactured by Kyodo chemical Co., Ltd.; ultraviolet absorbent)
were mixed and dissolved at 2OoC. 49.3 parts by weight of the
10 polythiol compound containing
4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
main components thus obtained was introduced and mixed, and thus a
15 mixed uniform solution was obtained. This uniform solution was
subjected to defoaming for 1 hour at 600 Pa, and then the uniform
solution was filtered using a 1 pm TEFLON (registered trademark)
filter. Subsequently, the filteredsolutionwasinjectedintoamold
formed from a glass mold and a tape. This mold was introduced into
20 an oven, the temperature was slowly increased from 10°C to 120°C,
and polymerization was carried out for 20 hours. After completion
of the polymerization, the mold was taken out from the oven, and a
resinwas obtainedbyreleasingtheproductfromthemold. The resin
thus obtainedwas f u r t h e r s u b j e c t e d t o a n n e a l i n g for4 hours at130°C.
5 The properties of the lens thus obtained are shown in Table-2.
[00811
[Examples C-2 to C-101
Polythiol compounds containing
4,8-dimercaptomethyl-1,ll-dimercapto-3,6,9-trithiaundecane,
10 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as
main components were respectively produced in the same manner as in
Example C-1, except that the production conditions described in
Table-l were used. The properties of the polythiol compounds thus
15 obtained are shown in Table-1. Furthermore, the viscosities after
7 hours ofthe polymerizable compositions were measured, and plastic
lenses were produced, in the same manner as in Example C-1. The
results are shown in Table-2.
[00821
2 0 [Example D-1]
(Synthesis of polythiol containing
bis(mercaptomethyl)-3,6,9-trithia-l,ll-undecanedithiol as a main
component)
In a reactor, 51.2 parts by weight of 2-mercaptoethanol, 26.5
25 parts by weight of degassed water (dissolved oxygen concentration:
2 ppm), and 0.16partsbyweightofa 49wt% aqueous solutionof sodium
hydroxide were introduced. 61.99 parts by weight of epichlorohydrin
were added dropwise thereto over 6.5 hours at g0C to 13OC, and
subsequently, the mixture was stirred for 40 minutes. Production
of 1-chloro-3-(2-hydroxyethy1thio)-2-propanol was confirmed from
NMR data.
5 Next, 150.0partsbyweightofa17.3%aqueous solutionof sodium
sulfide was added dropwise over 4.5 hours at 5OC to 42OC, and
subsequently, the mixture was stirred for 40 minutes. Production
of a tetra01 compound of formula (4) was confirmed from NMR data.
Next, 117.4 parts by weight of thiourea having a purity of 99.90%
10 was introduced, and 84.3 parts by weight of hydrochloric acid gas
having a purity of 90.7% was blown therein. The mixture was stirred
for 3 hours under reflux at llO°C, and thereby a reaction which forms
thiuronium salt was carried out. The reaction mixture was cooled
to 45OC, and then 214.0 parts by weight of toluene was added thereto,
15 and the mixture was cooled to 26°C. 158.4 parts by weight of a 25
wt% aqueous ammonia solution was introduced over 25 minutes at 26"C
to 46OC, andahydrolyticreactionwas carriedoutbyagingthemixture
for 1 hour at 54'C to 62'C. Thus, a toluene solution of a polythiol
containing
20 4,8-dimercaptomethyl-l,ll-dimercapto-3,G,9-trithiaundeca1~e,
4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as
main components was obtained. 59.4 parts by weight of 36%
hydrochloricacidwas addedtothetoluene solution, andacidwashing
25 for 30 minutes at 33OC to 4OoC was performed two times. 118.7 parts
by weight of degassed water (dissolved oxygen concentration: 2 ppm)
was added thereto, and washing for 30 minutes at 35OC to 45°C was
performed five times. Toluene and a trace amount of water were
removed under heating at reduced pressure, and then the residue was
filtered under reduced pressure using a 1.2 pm PTFE type membrane
filter, and thus 115.0 parts by weight of a polythiol compound
5 containing
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane,
4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as
main components was obtained. The properties of the polythiol
10 compound thus obtained are shown in Table-1. Measurement of the
viscosity after 7 hours of the polymerizable composition was carried
out in the same manner as in Example C-1. The results are shown in
Table-2.
Identification of these polythiol compounds was carried out by
15 NMR, and the same results as those obtained in Example C-1 were
obtained.
[00831
(Production of plastic lens)
50.7 parts by weight of m-xylylene diisocyanate, 0.01 parts by
20 weight of dibutyltin dichloride as a curing catalyst, 0.10 parts by
weight of ZELEC UN (trade name, product of Stepan Company; acidic
phosphoric acid ester), and 0.05 parts by weight of BIOSORB 583
(manufactured by Kyodo chemical Co., Ltd.; ultraviolet absorbent)
were mixed and dissolved at 2OoC. 49.3 parts by weight of the
25 polythiol compound containing
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane,
4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as
main components thus obtained was introduced and mixed thereto, and
thus a mixed uniform solution was obtained. This uniform solution
was subjected to defoaming for 1 hour at 600 Pa, and then the uniform
5 solution was filtered using a 1 pm TEFLON (registered trademark)
filter. Subsequently, the f i l t e r e d s o l u t i o n w a s i n j e c t e d i n t o a m o l d
formed from a glass mold and a tape. This mold was introduced into
an oven, the temperature was slowly increased from 10°C to 120°C,
and polymerization was carried out for 20 hours. After completion
10 of the polymerization, the mold was taken out from the oven, and a
resin tias obtainedbyreleasingtheproductfromthemold. The resin
thusobtainedwas f u r t h e r s u b j e c t e d t o a n n e a l i n g f o r 4 hours at130°C.
The properties of the lens thus obtained are shown in Table-2.
[0084]
15 [Examples D-2 to D-101
Polythiol compounds containing
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane,
4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as
20 main components were respectively produced in the same manner as in
Example D-1, except that the production conditions described in
Table-1 were used. The properties of the polythiol compounds thus
obtained are shown in Table-1. Furthermore, the viscosities after
7 hours ofthe polymerizable compositions weremeasured, and plastic
25 lenses were produced, in the same manner as in Example D-1. The
results are shown in Table-2.
[0085]

Example
Example
Example
Example .=-
Example
Example
D-7
Example
Example
Example
D-10
(continued)
Feed time
Condition 111 Monomer analysis values
O C
Condition I: Reaction conditions for 2-mercaptoethanol and epichlorohydrin
Acid Acid Color Specific Acidity Water Viscosi Refract NH4
concentra washing gravity tY ive
tion temperat index
ure
O C
Condition 11: Feed conditions for the aqueous ammonia solution for the hydrolytic reaction
minutes % OC P P ~ P P ~ mPa.s P P ~
Condition 111: Conditions for hydrochloric acid washing
[0086]
I I I OC I OC I minutes
Table-2
Example
9-11 26-50 3 C
C-1
Condition I
Example
9-13 26-50 2 E
C-2
Example
9-12 26-50 2 8
C-3
Condition I1
Example
9-13 26-50 2 8
-C-4 ---
Example
9-12 26-50 2 8
C-5
1 Example C-6 1 9-12 1 26-50
Example
9-12 26-50 2 8
C-7
Example
9-12 26-50 30
C-8
Example
9-12 26-50 2 8
C-9
Example
9-13 26-50 3 0
C-10
Resin evaluation
transparency
Viscosity
after 7 h
( * I
Condition I11
9 OC mPa . s
Hydrochloric
acid
concentration
Acid washing
temperature
on acid washing

[00871
[Examples F-1 to F-10 and Comparative Examples C-1 to C-61
Polythiol compounds containing
4,8-dimercaptomethyl-1,ll-dimercapto-3,6,9-trithiaundecane,
5 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and
5,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane as
main components were respectively produced in the same manner as in
Example C-1, except that the production conditions described in
Table-3wereused. Theviscositiesafter7hoursofthepolymerizable
10 compositions were measured, and plastic lenses were produced, in the
samc manner as in Example C-1. The results are shown in Table--3.
[00881
ransparency
concentration
Example F-8
Example F-9
Example F-10
9-13
8-13
7-12
32-40
32-40
31-42
10
32
32
36
36
36
36-39
34-37
53-55
0
0
0
4.1
4.2
4.1
16
2 2
17
0
0
0
transparency
oncentration
Condition I: Reaction conditions for 2-mercaptoethanol and epichlorohydrin
Condition 11: Feed conditions for the aqueous ammonia solution for the hydrolytic reaction
Condition 111: Conditions for hydrochloric acid washing
5 ( * ) A sample having a viscosity after 7 hours of 250 mPa-s or less was rated as 0, and a sample having
a viscosity after 7 hours of 1000 mPa.s or more was rated as X.
As discussed above, high quality plastic lenses were obtained
in Examples. On the other hand, in Comparative Examples, there was
a problem with at least one of color, loss degree of transpareancy,
5 and striation, so that plastic lenses having satisfactory quality
were not obtained. Furthermore, the polymerizable compositions
containing the polythiol compounds of Comparative Examples C-1 to
C-4 had viscosities after 7 hours of 1000 mPa.s or more, and thus
it was made clear that the production stability of plastic lenses
10 was affected thereby.
Fromthe viewpoint of heat stability and the like ofthe product
containing an intermediate in the production process, it is
preferable to set the temperature to 55OC or lower under Conditions
I11 (hydrochloric acid washing). When the temperature is in this
15 temperature range, a polythiolcompoundhavingexcellent qualitycan
be stably produced. From this point of view, it is more preferable
to set the temperature to 30°C or lower under Condition I (reaction
between 2-mercaptoethanol and epichlorohydrin) .
Moreover, at the time of actual production, it is necessary to
20 consider that the volume efficiency (inconvenience such as
precipitation during operation), stirrability, and a cooling
operation may be needed when the operation temperature is too low
as compared with the preceding process. From this viewpoint, in
regard to Conditions I (reaction between 2-mercaptoethanol and
25 epichlorohydrin), it is preferable to select the operation
temperature to be 2OC or higher.
[0090]
From the above r e s u l t s , it was made c l e a r t h a t when a polythiol
compound obtained by adding aqueous ammonia wi~thin 80 minutes while
maintaining the r e a c t i o n s o l u t i o n a t a temperature of 20°C t o 60°C
t o hydrolyze an isothiuronium s a l t under Conditions 11; adding
5 hydrochloricacidwhichis a concentration of 30%to 3 6 % t o a solution
containing a polythiol compound and washing the solution a t a
temperature of 30°C t o 55OC under Conditions 111; and thereby
purifyingthepolythiolcompound, is used, a p l a s t i c l e n s formed from
apolythiourethane-basedresinhavingexcellentqualitysuchascolor,
10 transparency, andstriationcanbeproduced. Furthermore, according
t o the present invention, it was made clear t h a t even i n the case
where a polythiol compound is repeatedlyproduced i n the production
i n a n a c t u a l i n d u s t r i a l scale, plasticlenseshavingadesiredproduct
quality are stably obtained without any fluctuation i n the product
15 quality of the polythiol compound between d i f f e r e n t production
batches.
[00911
This application claims p r i o r i t y from Japanese Patent
Application No. 2012-179896 f i l e d August 1 4 , 2012, the e n t i r e
20 disclosure of which is incorporated herein by reference.
[00921
The invention includes the following embodiments.
[ a l l A method for producing a polythiol compound, comprising:
astepforreactingapolyalcoholcompoundtoreactwiththiourea
25 in thepresence ofhydrogenchloridetoobtainanisothiuroniumsalt;
and
a step for adding, while maintaining a r e a c t i o n s o l u t i o n
containing the isothiuronium salt thus obtained at a temperature of
20°C to 60°C, aqueous ammonia to the reaction solution within 80
minutes, thereby hydrolyzing the isothiuronium salt to obtain a
polythiol compound.
5 [a21 The method for producing a polythiol compound according
to [all, further including, after the step for hydrolyzing the
isothiuronium salt to obtain a polythiol compound,
a step for adding hydrochloric acid which is a concentration
of 25% to 36% to the solution containing the polythiol compound thus
10 obtained, washing the solution at a temperature of 20°C to 50°C to
purify the polythiol compound.
[0093]
[a31 The method for producing a polythiol compound according
to [all or [a21, further including, before the step for reacting the
15 polyalcohol compound with thiourea to obtain an isothiuronium salt,
a step for reacting 2-mercaptoethanol with an epihalohydrin
compound represented by the following formula (1) at a temperature
of 2OC to 50°C to obtain a polyalcohol compound represented by the
following formula (2) .
(wherein X represents a halogen atom)
[0094]
[a41 The method for producing a polythiol compound according
to [a31, wherein the step for reacting 2-mercaptoethanol with an
5 epihalohydrin compound includes
a step for reacting 2-mercaptoethanol with an epihalohydrin
compound represented by the following formula (1) at a temperature
of 2OC to 20°C, and thereby obtaining a compound represented by the
following formula (3) ; and
(wherein X represents a halogen atom)
a step for reactingthe compound representedbyformula (3) with
2-mercaptoethanol at a temperature of 10°C to 50°C to obtain a
polyalcohol compound represented by the following formula (2).
[a51 The method for producing a polythiol compound according
to [a31 or [a4], wherein the polythiol compound is
4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane.
[0095]
[a61 The method for producing a polythiol compound according
10 to [all or [a2], further including, before the step for reacting the
polyalcohol compound with thiourea to obtain an isothiuronium salt,
a step for reacting 2-mercaptoethanol with an epihalohydrin
compound represented by the following formula (1) at a temperature
of Z°C to 20°C, and thereby obtaining a compound represented by the
15 following formula (3) ; and
(wherein X represents a halogen atom)
a step for reactingthe compound representedby formula (3) with
sodium sulfide to obtain a polyalcohol compound represented by the
following formula (4).
5
[a71 The method for producing a polythiol compound according
to [a6], wherein the polythiol compound includes one kind or two or
more kinds selected from the group consisting of
4,8-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane,
10 4,7-dimercaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane, and
5,7-dimemrcaptomethyl-l,ll-dimercapto-3,6,9-trithiaundecane.
[a81 Amethodforindustrialmanufacture of apolythiolcompound,
using the method according to any one of [all to [a7].
[a91 A polymerizable composition for optical materials,
15 comprising the polythiol compound obtained by the method according
to any one of [all to [a8].
[a101 A molded product obtained by curing the polymerizable
composition for optical materials according to [a9].
[all] A plastic lens comprising the molded product according
to [alO].

CLAIMS
1. A method for producing a polythiol compound, comprising:
a step for reacting 2-mercaptoethanol with an epihalohydrin
5 compoundrepresentedbythefollorfingformula (1) toobtainacompound
represented by the following formula (3);
(wherein X represents a halogen atom)
10 a step for r e a c t i n g t h e compound representedby formula (3) with
sodium s u l f i d e to obtain a polyalcohol compound represented by the
following formula ( 4 ) ;
a step for reacting the polyalcohol compound represented by
formula (4) thus obtained with thiourea in the presence of hydrogen
chloride to obtain an isothiuronium salt;
a step for adding, while maintaining a reaction solution
containing the isothiuronium salt thus obtained at a temperature of
5 20°C to 60°C, aqueous ammonia to the reaction solution within 80
minutes, thereby hydrolyzing the isothiuronium salt to obtain a
polythiol compound containing, as a main component, one kind or trio
or more kinds selected from the group consisting of compounds
represented by the following formulae (6) to (8); and
10
a step for adding hydrochloric acid which is concentration of
30% to 36% to the solution containing the polythiol compound thus
obtained, washing the solution at a temperature of 30°C to 55OC to
purify the polythiol compound.
2. The method for producing a polythiol compound according to claim
1, wherein the step for reacting 2-mercaptoethanol with the
epihalohydrin compound comprises:
5 a step for reacting 2-mercaptoethanol with the epihalohydrin
compound'represented by formula (1) at a temperature of 2OC to 30°C.
.3. Amethodforindustrialmanufactureofapolythiolcompound, using
the method according to claim 1 or 2.
10
4. A polymerizable composition f.or optical materials, comprising
a polythiol compound obtained by the method according to any one of
claims 1 to 3.
15 5. Amoldedproductobtainedbycuringthepolymerizable composition
for optical materials according to claim 4.
6. A plastic lens comprising the molded product according to claim 5.