JPH10120676A - Production of polythiol oligomer and polymer for optical material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably and selectively produce the subject compound having a refractive index higher than and an Abbe's number comparable to those of the polyol of a raw material b reacting a specific polyol with sulfur in the presence of a basic catalyst. SOLUTION: (B) A polyol having functionality of two or more is made to react with (C) sulfur in the presence of (A) a basic catalyst. Further, it is preferable that the reaction is carried out in the following manner: 2,5- dimercaptomethyl-1,4-dicyan, etc., is used as the component B; the component B and the component C are made to react at a molar ratio of (1:0.4) to (1:0.7); and, in the resultant polythiol oligomers consisting of oligomer or a mixture of oligomers, which contain at least one kind of dimers, trimers and tetramers, and may contain unreacted polythiol, the polythiol oligomers are separated into pure substances after the reaction is completed, and each polythiol oligomer is collected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polythiol oligomer and a polymer for an optical material, and more particularly, to a method for efficiently producing a polythiol oligomer having a disulfide bond useful as a raw material for a polymer for an optical material having excellent optical properties. The present invention relates to a method for producing the polymer well, and a polymer having excellent optical properties suitable for various optical materials, using a polythiol oligomer obtained by the method as a raw material. The polymer for optical materials of the present invention is preferably used for, for example, optical lenses, spectacle lenses, contact lenses, intraocular lenses, prisms, optical filters, optical fibers, optical disc substrates, and the like.

[0002]

2. Description of the Prior Art Compared with glass, plastics are lightweight, hard to break, and easy to dye. Therefore, plastics have recently been used for optical parts such as various lenses. Practical plastic optical materials include poly (diethylene glycol bisallyl carbonate), polymethyl methacrylate, and polycarbonate.

In general, optical materials made of transparent glass or plastic have a lower Abbe number as the refractive index increases, and vice versa. Therefore, it is generally very difficult to produce a plastic optical material having an increased refractive index and Abbe number simultaneously.

On the other hand, as a plastic lens having an increased refractive index and Abbe number at the same time, a polythiol comprising 2,5-dimercaptomethyl-1,4-dithiane (hereinafter referred to as DMMD) is reacted with a polyisocyanate. Polythiourethane lens is disclosed in JP-A-3-236386.
No., published in Japanese Unexamined Patent Publication No. DMMD which is a raw material monomer used in the production of the polythiourethane lens described in this patent publication has a refractive index of 1.646, an Abbe number of 35.2, a high refractive index and a high Abbe number. For,
Although the obtained polythiourethane lens also has a high refractive index and a high Abbe number, the development of a plastic lens having a higher refractive index and a higher Abbe number has been desired.

Therefore, DMMD is converted to methyl sulfoxide,
Oxidation with air in the presence of a catalyst such as ferric chloride
A method of producing a polythiourethane lens by obtaining an oligomer mixture of D and reacting the DMMD oligomer mixture with a polyisocyanate is disclosed in
3 and Japanese Patent Application Laid-Open No. 7-118390.

However, Japanese Patent Application Laid-Open No. Hei 7-11826 discloses
No. 3, Japanese Patent Application Laid-Open No. 7-118390 discloses that the reaction conditions (for example, temperature,
Humidity, etc.), the refractive index is 1.66 even if it is slightly changed.
5-1.680, Abbe number changes from 34.3 to 35.0, and is unstable, and a polythiourethane material having a constant refractive index and a constant Abbe number is obtained using such a raw material. Is difficult, and the D
The MMD oligomer mixture is not always practical as a raw material for an optical material.

On the other hand, as a method for obtaining disulfide, US Pat. No. 2,376,625 describes that an equimolar alkyl mercaptan (monothiol) is reacted with sulfur in the presence of an amine catalyst to form disulfide, trisulfide and tetrasulfide. A method for obtaining a mixture is disclosed.
"Journal of Organic Chemistry (J. Org. Chem.)", Vol. 32, p. 3833 (19
67)), using n-butylamine as a catalyst,
A method for producing disulfide, trisulfide, and tetrasulfide by reacting monothiol with sulfur is described. However, these documents do not propose a method for producing a polythiol oligomer using a polythiol having two or more functions as a starting material.

[0008]

SUMMARY OF THE INVENTION Under such circumstances, the present invention is to selectively and stably produce a polythiol oligomer having a higher refractive index than bifunctional or higher polythiol and an Abbe number comparable to the polythiol. The first object of the present invention is to provide a practical polymer for optical materials having a stable high refractive index and a high Abbe number by using the oligomer obtained by this method as a raw material. That is the second purpose.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, have found that by reacting a bifunctional or higher-functional polythiol with sulfur in the presence of a basic catalyst. Can achieve the first object, and the oligomer and poly (thio) obtained by this method
The present inventors have found that the second object can be achieved by copolymerizing an isocyanate group-containing compound or a polyfunctional vinyl group-containing compound, and have completed the present invention based on this finding.

That is, the first object of the present invention is achieved by a method for producing a polythiol oligomer having a disulfide bond, which comprises reacting a difunctional or higher polythiol with sulfur in the presence of a basic catalyst. .

A second object of the present invention is a polymer obtained by copolymerizing a polythiol group-containing compound with a poly (thio) isocyanate group-containing compound and / or a polyfunctional vinyl group-containing compound. This is achieved by a polymer for optical materials, wherein the polythiol group-containing compound is a polythiol oligomer obtained by the above method.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a method for producing a polythiol oligomer which achieves the first object of the present invention will be described.

In the method of the present invention, a polythiol having two or more functional groups is used as a raw material. The polythiol having two or more functional groups may be linear, branched, or cyclic, and if it has two or more mercapto groups (—SH), other functional groups such as an amine group It may have a functional group having active hydrogen such as a hydroxyl group. Examples of such bifunctional or higher polythiols include 2,2.
5-dimercaptomethyl-1,4-dithiane (DMM
D), pentaerythritol tetrakismercaptoacetate (PETMA), pentaerythritol tetrakismercaptopropionate (PETMP), trimethylolpropane trismercaptoacetate, 2,3-
Dimercapto-1-propanol, 1,2- (dimercaptoethylthio) -3-mercaptopropane, 1,2-
Bis-2- (mercaptoethylthio) -3-mercaptopropane, 1,2,3-trimercaptopropane, bis (2-mercaptoethyl) sulfide, ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol , Butanedithiol, hexanedithiol, benzenedithiol, benzenetrithiol, tolylenedithiol, xylylenedithiol and the like. These may be used alone or in combination of two or more. High refractive index, high Abbe number (low dispersion)
A particularly useful compound for obtaining a polythiol oligomer having the formula is 2,5-dimercaptomethyl-1,4-dithiane (DMMD).

In the method of the present invention, the above-mentioned difunctional or higher polythiol and sulfur are reacted in the presence of a basic catalyst to form a polythiol oligomer. For example, if the product is a dimer, the reaction formula

Embedded image (Wherein, R represents an organic group, and n is an integer of 1 or more, preferably 1, 2 or 3).

In the method of the present invention, the amount of sulfur used is 0.1 mol per mol of polythiol having two or more functional groups.
It is preferably in the range of 0.95 mol to 0.95 mol. If the amount is less than 0.1 mol, the conversion of polythiol is too low to be practical, and if it exceeds 0.95 mol, the amount of multimers having a large molecular weight, which is not preferable as a raw material for optical materials, increases, Unreacted sulfur may remain in the reaction solution. In consideration of the conversion, the performance as a raw material for optical materials, the reactivity of sulfur, and the like, a particularly preferred amount of sulfur to be used is in the range of 0.4 to 0.7 mol based on 1 mol of bifunctional or higher polythiol. is there.

The sulfur used in the present invention may be in any form, for example, crystalline, colloidal, powder or sulfur. Preferably, a material having a purity of 98% or more, more preferably 99% or more, is used.

The basic catalyst used in the method of the present invention comprises
Preferably it is ammonia or amine. The amine is
It may be any of a linear, branched or cyclic aliphatic amine or aromatic amine, and may be any of a primary amine, a secondary amine or a tertiary amine. Specific examples of the catalyst include ammonia, ethylamine, diethylamine, triethylamine, n-propylamine, isopropylamine, n-butylamine, s-butylamine,
Examples include t-butylamine, n-amylamine, morpholine, piperidine, substituted morpholine, substituted piperidine, and aniline, preferably diethylamine, triethylamine, n-butylamine, morpholine and piperidine. These may be used alone or in combination of two or more. The amount of ammonia or amine used as a catalyst depends on the raw material polythiol.
Usually 0.001 to 1.0 mol%, preferably 0.01
~ 0.1 mol%.

In the method of the present invention, the catalyst may be charged into the reaction system by previously mixing the catalyst with polythiol and sulfur, or by mixing polythiol and sulfur to dissolve all of the sulfur. This may be done later by adding a catalyst.

In the method of the present invention, a solvent may be used, if necessary. Specific examples of solvents that can be used include dichloromethane, chloroform, carbon tetrachloride, dichloroethane, halogenated hydrocarbons such as trichloroethane, aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, benzene, and toluene. Examples thereof include aromatic hydrocarbons, alcohols such as methanol, ethanol, and isopropanol, and ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran. Preferably, they are methanol and tetrahydrofuran. The amount of the solvent to be used can be appropriately determined according to the starting materials, the type of the catalyst, the reaction conditions, and the like.

In the method of the present invention, the reaction temperature is not particularly limited, but is usually a temperature in the range of room temperature to the boiling point of the solvent.
Preferably it is room temperature-120 degreeC.

The reaction time varies depending on various conditions such as the type of raw materials, the molar ratio between polythiol and sulfur, the type and amount of a catalyst, and the reaction temperature, and cannot be determined unconditionally. It is advantageous to react until no more remains. When the reaction solution is used as it is, or when a residual solution obtained by distilling off the solvent is used as a raw material of the polymer for optical materials, unreacted sulfur remains unpreferable.

The polythiol oligomer thus produced is preferably an oligomer or an oligomer mixture containing at least one of dimers, trimers and tetramers and optionally containing unreacted polythiols. is there. Usually, the reaction solution contains unreacted polythiol and plural types of oligomers.

In the present invention, when the reaction solution does not contain a solvent, the reaction solution may be used as it is, or when the reaction solution contains a solvent, the residual solution obtained by distilling off the solvent may be used as a raw material of a polymer for an optical material. If necessary, the unreacted polythiol and each oligomer may be isolated and purified, and each may be obtained as a single substance. The isolation and purification method is not particularly limited, and may be a conventionally used method.For example, when the reaction solution does not contain a solvent, the reaction solution is directly subjected to column chromatography. After letting
It can be isolated and purified by subjecting it to column chromatography.

When the polythiol oligomer obtained by the method of the present invention is used as a raw material for an optical material, 2,5-dimercaptomethyl-1,4-dithiane (DMMD) is used as a bifunctional or higher polythiol. Are reacted with sulfur in a molar ratio of 1: 0.4 to 1: 0.7,

Embedded image At least one of dimers, trimers and tetramers represented by
It is preferred to produce an oligomer or oligomer mixture that contains the seeds and may contain unreacted 2,5-dimercaptomethyl-1,4-dithiane.

If necessary, after completion of the reaction, the oligomer is isolated and purified as described above to obtain a dimer, trimer and tetramer of 2,5-dimercaptomethyl-1,4-dithiane. At least one oligomer selected from monomers may be obtained.

Next, a polymer for an optical material which achieves the second object of the present invention will be described.

The polymer for an optical material of the present invention comprises a compound having a polythiol group (monomer component A), a compound having a poly (thio) isocyanate group (monomer component B) and / or
Alternatively, it is a copolymer with a polyfunctional vinyl group-containing compound (monomer component C), and has stable optical characteristics suitable for an optical material having a high refractive index and a high Abbe number (low dispersion). Hereinafter, each monomer component will be described.

Monomer Component A In the present invention, a polythiol group-containing compound is used as the monomer component A, and the polythiol oligomer obtained by the above-mentioned method of the present invention is used as the polythiol group-containing compound. That is, an oligomer or oligomer mixture containing at least one dimer, trimer, and tetramer of a polyfunctional or higher-functional polythiol and containing or not containing an unreacted polythiol, or a dimer or trimer And simple substances of various oligomers such as tetramers can be preferably used. As such, the reaction solution obtained by the above-mentioned method of the present invention may be used as it is (when no solvent is used), or a residual solution obtained by distilling off the solvent in the reaction solution (when a solvent is used). Any of various oligomers obtained by isolating and purifying the oligomer in the reaction solution may be used. In this case, various oligomers alone may be used in appropriate combination of two or more.

The polythiol oligomer obtained by the method of the present invention is substantially composed of only a compound having two or more mercapto groups and contains a compound having a disulfide bond in the molecule. From
Determining the reaction conditions results in having a constant high refractive index and a constant high Abbe number. Therefore,
By using this polythiol oligomer, a polymer having a stable high refractive index and a stable high Abbe number can be obtained.

Among such polythiol oligomers, a compound obtained by using 2,5-dimercaptomethyl-1,4-dithiane (DMMD) as a bithiol or higher polythiol,

Embedded image At least one of dimers, trimers and tetramers represented by
An oligomer or oligomer mixture containing a seed and containing or not containing unreacted 2,5-dimercaptomethyl-1,4-dithiane, or an oligomer or oligomer obtained by isolating and purifying an oligomer in a reaction solution. At least one oligomer selected from dimers, trimers and tetramers of 5-dimercaptomethyl-1,4-dithiane is preferred from the viewpoint of optical properties.

In the present invention, if necessary, a disulfide may be used as a monomer component together with the polythiol oligomer obtained by the above-described method of the present invention for the purpose of adjusting the viscosity thereof to facilitate the polymerization reaction. A polythiol compound having no bond can be used as appropriate. Here, the polythiol compound having no disulfide bond has no disulfide bond and has two or more mercapto groups (—SH), but other functional groups other than the mercapto group, for example, an amino group And a functional group having an active hydrogen such as a hydroxy group. Specific examples of the polythiol compound having no disulfide bond include 2,5-dimercaptomethyl-1,4
-Dithiane (DMMD), pentaerythritol tetrakismercaptoacetate (PETMA), pentaerythritol tetrakismercaptopropionate (PE
TMP), trimethylolpropane trismercaptoacetate, 2,3-dimercapto-1-propanol,
1,2- (dimercaptothio) -3-mercaptopropane, 1,2-bis-2- (mercaptoethylthio) -3
-Mercaptopropane, 1,2,3-trimercaptopropane, bis (2-mercaptoethyl) sulfide, ethanedithiol, 1,2-propanedithiol, 1,3
-Propanedithiol, butanedithiol, hexanedithiol, benzenedithiol, benzenetrithiol, tolylenedithiol, xylylenedithiol and the like. Preferably, trimethylolpropane tris mercapto acetate, pentaerythritol tetrakis mercapto propionate (PETMP), pentaerythritol tetrakis mercapto acetate (PET)
MA).

The mixing ratio between the polythiol oligomer and the polythiol compound having no disulfide bond is as follows:
There is no particular limitation, and it is appropriately selected according to the viscosity of the polythiol oligomer.
1: 100, preferably 100: 1 to 1:
1, particularly preferably in the range of 100: 1 to 2: 1. If the proportion of the polythiol compound having no disulfide bond is too large, the properties of the polythiol oligomer are lost, and a desired polymer for an optical material having a high refractive index and a high Abbe number (low dispersibility) may not be obtained. .

Monomer Component B In the present invention, a poly (thio) isocyanate group-containing compound is used as the monomer component B. Here, the poly (thio) isocyanate group-containing compound means a polyisocyanate group-containing compound or a polythioisocyanate group-containing compound. That is, at least 2
It is composed of a compound having two or more isocyanate groups (-NCO) or thioisocyanate groups (-NCS). The poly (thio) isocyanate group-containing compound may be any compound that can be used in the field of optical materials, and the type thereof is not particularly limited. However, since the viscosity of the monomer component A is relatively high, Generally, low viscosity poly (thio) isocyanate compounds are preferred. Specific examples of the poly (thio) isocyanate compound that can be used in the present invention include, for example, hexamethylene diisocyanate, isophorone diisocyanate, bis (isocyanatomethyl) cyclohexane (HXDI), 1,3-diisocyanatecyclohexane (CHDI), 1,3 , 5
-Triisocyanate cyclohexane, dicyclohexylmethane diisocyanate, bis (isocyanatemethyl) bicyclopentane (NBDI), bis (isocyanatemethyl) bicycloheptane, benzene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, lysine ester triisocyanate, triisocyanate cyclohexane, tris ( Isocyanatomethyl) cyclohexane (HMTI), bicycloheptane triisocyanate, lysine ester triisocyanate (LyTI), 2,5-diisocyanatomethyl-
Examples include polyisocyanates such as 1,4-dithiane, and corresponding polythioisocyanates.
Of these, polyisocyanates are preferred. More preferably, bis (isocyanatomethyl) cyclohexane (HXDI), 1,3-diisocyanatocyclohexane (CHDI), 1,3,5-triisocyanatecyclohexane, bis (isocyanatomethyl) bicyclopentane (NBDI), tris (isocyanatemethyl)
Cyclohexane (HMTI) and 2,5-diisocyanatomethyl-1,4-dithiane, and particularly preferably 1,3-diisocyanatocyclohexane (CHD)
I), 1,3,5-triisocyanatecyclohexane and 2,5-diisocyanate-1,4-dithiane.

In the present invention, as the monomer component B, one compound containing a poly (thio) isocyanate group may be used alone, or two or more compounds may be used in combination.

Monomer Component C In the present invention, a polyfunctional vinyl group-containing compound is used as the monomer component C. The polyfunctional vinyl group-containing compound comprises a compound having at least one vinyl group and / or a compound having at least one vinyl group and at least one functional group other than the vinyl group. The type of the polyfunctional vinyl group-containing compound is not particularly limited as long as it is generally used in the field of optical materials. However, since the viscosity of the monomer component A is relatively high, the polyfunctional vinyl group-containing compound generally has a low viscosity. Vinyl compounds are preferred. Specific examples of the polyfunctional vinyl compound that can be used in the present invention include 2,5-bis (2-thia-3-butenyl) -1,4-dithiane (TBD), styrene, chlorostyrene, dibromostyrene, divinyl Benzene, methyl (meth) acrylate, N-phenylmaleimide, N
-Cyclohexylmaleimide, phenyl (meth) acrylate, phenylthio (meth) acrylate, di (meth) acrylphenyl sulfide, and the like. Preferably, 2,5-bis (2-thia-3-butenyl) -1,
Examples thereof include 4-dithiane (TBD) and divinylbenzene, and particularly preferred is 2,5-bis (2-thia-3-butenyl) -1,4-dithiane (TBD).

In the present invention, as the monomer component C, the above polyfunctional vinyl group-containing compound may be used alone or in combination of two or more.

Next, the mixing ratio of each monomer component when producing the polymer for an optical material of the present invention will be described.

When two components of component A (polythiol group-containing compound) and component B [poly (thio) isocyanate group-containing compound] are used as monomer components, the mixing ratio of component A and component B is In equivalence ratio, usually 1: 2-
It is good to select in the range of 2: 1, preferably 1: 2 to 1: 1, particularly preferably 1: 1.2 to 1: 1. Component A (polythiol group-containing compound) as a monomer component
When two components, ie, and component C (polyfunctional vinyl group-containing compound) are used, the mixing ratio of component A to component C is usually 1: 1000 to 1: 1, preferably 1: 1, in terms of the functional group equivalent ratio. 1
It is better to select in the range of 00 to 1: 1. Furthermore, when three components, Component A, Component B and Component C, are used as the monomer components, the mixing ratio of Component A, Component B and Component C is usually 1: 10: 10,000 to equivalent ratio of functional groups. 10: 0.0
1: 1, preferably 1: 10: 100 to 10: 0.1:
It is better to choose in the range of 1.

In the production of the polymer for an optical material of the present invention, in addition to the monomer components A, B and C, an ultraviolet absorber, an antioxidant, a dye and the like can be appropriately added as required.

Next, a method for producing the polymer for an optical material of the present invention will be described.

In the production of the polymer for an optical material of the present invention, a monomer mixture containing at least a monomer component A and a monomer component B and / or a monomer component C is prepared.
The polymerization can be carried out in the presence of an appropriate amount of a polymerization catalyst by a known polymerization method such as thermal polymerization or photopolymerization. The conditions for the polymerization reaction are not particularly limited, and the polymerization may be performed under the conditions generally used in the field of optical materials.

The production of an optical product comprising the polymer for a high refractive index optical material of the present invention can be carried out by a casting (casting polymerization) method, a cutting and polishing method, an injection molding method, or the like. When a product is produced by a cast (cast polymerization) method, an internal release agent may be used in some cases.

The polymer for an optical material of the present invention has a high refractive index and a high Abbe number (low dispersion), and the refractive index and the Abbe number between product lots are constant. , Prism, optical fiber, information recording substrate,
It can be suitably used as a material for optical products such as a coloring filter and an infrared absorption filter.

[0044]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The properties were measured according to the following methods.

(1) ¹ H-NMR spectrum Measured using a JEOL EX-270 NMR spectrometer.

(2) IR absorption spectrum Measured using a Horiba FT300 infrared spectrometer.

(3) Refractive index Nd and Abbe number Vd Measured at 25 ° C. using a KPR-200 precision refractometer, manufactured by Calnew, unless otherwise specified.

(4) Appearance Observed with the naked eye.

Example 1 6.4 g of powdered sulfur was placed in a 500 ml round bottom flask.
(0.2 mol), 2,5-dimercaptomethyl-1,4
-84.8 g of dithiane (DMMD) (0.4 mol, DM
MD / S molar ratio = 2/1), 0.0146 g of diethylamine (DEA) as a catalyst (0.
05 mol%) and 95 ml of tetrahydrofuran (THF) as a solvent, and the mixture was heated with stirring in an oil bath at 60 ° C. At the same time as the sulfur began to dissolve, the reaction proceeded while a brown color developed on the liquid surface, and the generation of a large amount of hydrogen sulfide bubbles continued for about 20 minutes. After about 30 minutes, when generation of air bubbles was no longer observed, the bath temperature was raised to 100 ° C., and THF was distilled off. After most of the THF has been distilled off,
The THF was completely distilled off by bubbling nitrogen through for 2 hours. Thereafter, vacuum degassing is performed at 100 ° C. to obtain a colorless and transparent viscous liquid 8
4.5 g were obtained.

The viscous liquid was analyzed by gas chromatography (Tosoh column: G2000HXL, detector: RI, flow rate: 0.8 ml / min, temperature: 40 ° C.). Met. Thus, the conversion of DMMD to oligomers was 78.3%.

The refractive index of this viscous liquid is 1.68.
2. The Abbe number was 34.7. Further, ¹ H-NM
The results of R analysis and IR analysis are as follows.

¹ H-NMR (solvent: CDCl ₃ , internal standard: tetramethylsilane) δ (ppm): 1.61 (t, 1.0 H), 2.83-
3.24 (m, 10.0H) IR: 2550 cm ^-1 (νSH for thiol), 550 cm ^-1 (νS for disulfide
S) FIG. 1 shows the ¹ H-NMR spectrum, and FIG. 2 shows the IR spectrum.

Examples 2 to 4 The same operation as in Example 1 was performed except that the type of the catalyst and the polymerization conditions were changed as shown in Table 1. Table 1 shows the DMMD conversion and the refractive index and Abbe number of the obtained oligomer mixture (including unreacted) of the viscous liquid.

As shown in Table 1, by keeping the reaction ratio between DMMD and sulfur constant, an oligomer mixture (including unreacted) having a constant refractive index and Abbe number can be selectively and stably obtained. I understood that.

The analytical values of the oligomer mixture by gas chromatography in Example 2 are as follows, and the conversion of DMMD to oligomer was 78.2%.
Met.

[0057] Example 5 Example 1 except that the molar ratio of DMMD / S was 3/2.
The same operation as described above was performed to obtain an oligomer mixture (including unreacted). Table 1 shows the conversion of DMMD and the refractive index and Abbe number of the oligomer mixture (including unreacted).

[0058]

[Table 1]

(Note) DMMD: 2,5-dimercaptomethyl-1,4-dithiane DEA: diethylamine TEA: triethylamine MPR: morpholine PPD: piperidine Examples 6 to 12 The types and amounts of polythiols and catalysts as starting materials are shown in the table. An oligomer mixture of polythiol was prepared in the same manner as in Example 1 except that the mixture was changed as shown in Example 2, and the refractive index and Abbe number were measured and the conversion was determined. Table 2 shows the results.

For reference, Table 3 shows the refractive index and Abbe number of the polythiol used as a starting material in Examples 1 to 12 described above.

[0061]

[Table 2]

[0062]

[Table 3]

(Note) DMMD 2,5-dimercaptomethyl-1,4-dithiane PETMA Pentaerythritol tetrakismercaptoacetate PETMP pentaerythritol tetrakismercaptopropionate TMTG Trimethylolpropane trismercaptoacetate m-XDT m-xylylene diothiol DMP 2,3-dimercapto-1-propanol BMES bis (2-mercaptoethyl) sulfide DMMP 2,3- (dimercaptoethylthio) -1
-Mercaptopropane From Tables 1 and 2, it can be seen that polythiol oligomers having disulfide bonds, such as dimers and trimers of bifunctional or higher polythiols, can be selectively and stably obtained by the method of the present invention. it is obvious. Tables 1 and 2 are
By comparing with Table 3, it is clear that the polythiol oligomer produced by the method of the present invention has a higher refractive index than the starting polythiol and has the same Abbe number.

Example 13 0.1 mol (monomer component A) of the DMMD oligomer mixture (including unreacted components) obtained in Example 1, 0.1 mol of m-xylylene diisocyanate (XDI) (monomer component B) and A mixture corresponding to 0.05 wt% of dimethyltin dichloride (DMTDC) was sufficiently stirred to be uniform, and then poured into two glass molds for lens molding. This was heated to 50 ° C. over 10 hours, then to 60 ° C. over 5 hours, and further heated to 120 ° C. over 2.5 hours.
C. and finally heat polymerization at 120.degree. C. for 2.5 hours to obtain a lens-shaped colorless and transparent polymer. Table 4 shows properties of the obtained polymer.

Example 14 0.1 mol of the DMMD oligomer mixture (including unreacted components) obtained in Example 1 (monomer component A), 2,5-bis (2-thia-3-butenyl) -1,4 -Dithiane (TB
D) A mixture of 0.1 mol (monomer component C) and 0.05 wt% equivalent of azobisdimethylvaleronitrile (V-65) was sufficiently stirred and homogenized, and then polymerized in the same manner as in Example 13. Thus, a polymer for a lens material was obtained. Table 4 shows properties of the obtained polymer.

Examples 15 to 18 Polymerization was carried out in the same manner as in Example 13 except that each of the polyisocyanate group-containing compounds shown in Table 4 was used as the monomer component B to obtain a polymer for a lens material. Table 4 shows properties of the obtained polymer.

Examples 19 to 22 Each of the polyisocyanate group-containing compounds shown in Table 4 was used as a monomer component B at the compounding ratio shown in Table 4, and the polyfunctional vinyl group-containing compound shown in Table 4 was used as a monomer component C.
Polymerization was carried out in the same manner as in Example 13 except for using the compounding ratio shown in Table 4, to obtain a polymer for lens material. Table 4 shows properties of the obtained polymer.

Examples 23 to 27 At the compounding ratios shown in Table 4, the DMMD oligomer mixture (including unreacted) obtained in Example 1 and 2,5-dimercaptomethyl-1,4-dithiane (DMMD) were used. Same as Example 13 except that it was used as monomer component A, and that each polyisocyanate compound and each polyfunctional vinyl group-containing compound shown in Table 4 were used as monomer components B and C, respectively, at the compounding ratio shown in Table 4. To obtain a polymer for lens material. Table 4 shows the physical properties of the obtained polymer.
Shown in

Comparative Example 1 2,5-dimercaptomethyl-1,4-dithiane (DM
MD, monomer) and m-xylylene diisocyanate (XDI) in a molar ratio of 50:50 (Polymer No. 3-236386, Example 1). Is 1.66 and Abbe number (V
d) was 32.

Comparative Example 2 2,5-dimercaptomethyl-1,4-dithiane (DM
MD, monomer) and 1,3-bis (isocyanatomethyl) cyclohexane (HXDI) in a molar ratio of 50:50.
(Polymer obtained by polymerization at a blending ratio of
No. 386, Example 8) has a refractive index (nd) of 1.62.
And the Abbe number (Vd) was 38.

[0071]

[Table 4]

DMMDO: DMMD obtained in Example 1
Oligomer mixture CHDI: 1,3-diisocyanatocyclohexane HMTI: tris (isocyanatomethyl) cyclohexane NBDI: bis (isocyanatomethyl) bicyclopentane HXDI: 1,3-bis (isocyanatomethyl) cyclohexane TBD: 2,5-bis (2-thia) -3-butenyl)-
1,4-dithiane DMMD: 2,5-dimercaptomethyl-1,4-dithiane LyTI: lysine ester triisocyanate From the results in Table 4, the polymers obtained in Examples 13 to 27 have a refractive index (nd) of Is extremely high at 1.645 to 1.694, and the Abbe number (Vd) is also high at 33.0 to 37.0 (low dispersibility), indicating that both physical properties are simultaneously improved. In contrast, in Comparative Example 1, the refractive index was relatively high, but the Abbe number was as low as 32. In Comparative Example 2, the Abbe number is as high as 38, but the refractive index is low.

[0073]

According to the present invention, a polythiol oligomer having a disulfide bond can be selectively and stably produced from a polythiol having two or more functionalities as a raw material. This polythiol oligomer has a higher refractive index than the raw material polythiol and an Abbe number equivalent to the polythiol. Therefore, by using this polythiol oligomer, a polymer for an optical material having a high refractive index and a high Abbe number (low dispersion) can be provided.

According to the present invention, JP-A-7-118390
Unlike the polymer using a DMMD oligomer mixture as a polythiol group-containing compound as disclosed in Japanese Patent Application Publication No. (Dispersibility), and an optical product such as a lens having excellent optical properties can be industrially provided.

[Brief description of the drawings]

[1] ¹ H-NM of the obtained 2,5-mercaptomethyl-1,4-dithiane oligomer mixture in Example 1
It is an R spectrum figure.

FIG. 2 is an IR absorption spectrum of the oligomer mixture of 2,5-dimercaptomethyl-1,4-dithiane obtained in Example 1.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // C07B 61/00 300 C07B 61/00 300

Claims (18)

[Claims] 1. A method for producing a polythiol oligomer, comprising reacting a bifunctional or higher polythiol with sulfur in the presence of a basic catalyst. 2. The polythiol oligomer according to claim 1, wherein the polythiol oligomer is an oligomer or an oligomer mixture containing at least one of a dimer, a trimer and a tetramer and optionally containing an unreacted polythiol. Method. 3. After completion of the reaction, the oligomer is isolated and purified,
3. The method according to claim 1, wherein each polythiol oligomer alone is obtained. 4. The method according to claim 1, wherein the molar ratio of the difunctional or higher polythiol to sulfur is 1: 0.1 to 1: 0.95.
Or the method of 3. 5. The process according to claim 4, wherein the bifunctional or higher polythiol is reacted with sulfur in a molar ratio of 1: 0.4 to 1: 0.7. 6. The polythiol having two or more functional groups is 2,5-
Dimercaptomethyl-1,4-dithiane, pentaerythritol tetrakismercaptoacetate, pentaerythritol tetrakismercaptopropionate, trimethylolpropane trismercaptoacetate, 2,
3-dimercapto-1-propanol, 1,2- (dimercaptoethylthio) -3-mercaptopropane, 1,
2-bis-2- (mercaptoethylthio) -3-mercaptopropane, 1,2,3-trimercaptopropane,
Selected from bis (2-mercaptoethyl) sulfide, ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, butanedithiol, hexanedithiol, benzenedithiol, benzenetrithiol, tolylenedithiol and xylylenedithiol The method according to any one of claims 1 to 5, wherein the method is at least one selected from the group consisting of: 7. A polythiol having two or more functional groups, such as 2,5
-Dimercaptomethyl-1,4-dithiane is reacted with sulfur in a molar ratio of 1: 0.4 to 1: 0.7 to give a compound of the formula At least one of dimers, trimers and tetramers represented by
3. The process of claim 2 wherein an oligomer or mixture of oligomers is prepared containing the species and optionally containing unreacted 2,5-dimercaptomethyl-1,4-dithiane. 8. After completion of the reaction, the oligomer is isolated and purified,
The method according to claim 7, wherein at least one oligomer selected from dimers, trimers and tetramers of 2,5-dimercaptomethyl-1,4-dithiane is obtained. 9. The method according to claim 1, wherein the basic catalyst is ammonia and / or an amine. 10. The method according to claim 9, wherein the amine is at least one selected from diethylamine, triethylamine, dibutylamine, morpholine and piperidine. 11. A polymer obtained by copolymerizing a polythiol group-containing compound with a poly (thio) isocyanate group-containing compound and / or a polyfunctional vinyl group-containing compound, wherein the polythiol group-containing compound is -10
A polymer for an optical material, comprising a polythiol oligomer obtained by the method according to any one of the above. 12. The polythiol group-containing compound is a polythiol oligomer obtained by the method according to any one of claims 1 to 10, further comprising 2,5-dimercaptomethyl as a polythiol compound having no disulfide bond. -1,4-dithiane, pentaerythritol tetrakismercaptoacetate, pentaerythritol tetrakismercaptopropionate, trimethylolpropane trismercaptoacetate, 2,3-dimercapto-1-propanol, 1,2- (dimercaptoethylthio) -3 -Mercaptopropane, 1,2-bis-
2- (mercaptoethylthio) -3-mercaptopropane, 1,2,3-trimercaptopropane, bis (2-
Mercaptoethyl) sulfide, ethanedithiol,
It is a combination of at least one selected from 1,2-propanedithiol, 1,3-propanedithiol, butanedithiol, hexanedithiol, benzenedithiol, benzenetrithiol, tolylenedithiol and xylylenedithiol. 12. The polymer for an optical material according to item 11. 13. A poly (thio) isocyanate group-containing compound comprising: 2,5-diisocyanatomethyl-1,4-dithiane, 1,3-diisocyanatocyclohexane,
1,3,5-triisocyanatocyclohexane, tris (isocyanatomethyl) cyclohexane, bis (isocyanatomethyl) bicyclopentane and 1,3-
13. The polymer for an optical material according to claim 11, which is at least one kind of polyisocyanate selected from bis (isocyanatomethyl) cyclohexane. 14. The polymer for an optical material according to claim 13, wherein the polyisocyanate is 2,5-diisocyanatomethyl-1,4-dithiane and / or 1,3-diisocyanatocyclohexane. 15. The method according to claim 15, wherein the polyfunctional vinyl group-containing compound is 2,5.
The polymer for an optical material according to any one of claims 11 to 14, which is -bis (2-thia-3-butenyl) -1,4-dithiane. 16. A polymer obtained by copolymerizing a polythiol group-containing compound and a poly (thio) isocyanate group-containing compound such that the equivalent ratio of functional groups is 1: 2 to 2: 1. The polymer for an optical material according to any one of claims 11 to 14. 17. The polymer obtained by copolymerizing a polythiol group-containing compound and a polyfunctional vinyl group-containing compound such that the equivalent ratio of the functional groups is 1: 1000 to 1: 1. 16. The polymer for an optical material according to 11, 12, or 15. 18. A polymer comprising a polythiol group-containing compound, a poly (thio) isocyanate group-containing compound and a polyfunctional vinyl group-containing compound having a functional group equivalent ratio of 1: 10: 1.
The polymer for an optical material according to any one of claims 11 to 15, which is obtained by copolymerizing 000 to 10: 0.01: 1.