JP6241208B2 - Method for producing polythiol compound for optical material - Google Patents

Description

  The present invention is suitably used for optical materials such as plastic lenses, prisms, optical fibers, information recording boards, filters, and especially plastic lenses.

In recent years, plastic materials have been widely used in various optical materials, particularly eyeglass lenses, because they are light and tough and easy to dye. The main performances required for optical materials, especially spectacle lenses, are low specific gravity, high transparency and low yellowness, high refractive index and high Abbe number as optical performance, and use thiourethane resin for optical lenses and it. With regard to the plastic lens, many applications have been filed, and a lens having a high refractive index, little coloring, and high transparency has been proposed. (Patent Documents 1 and 2)
However, many of the polythiol compounds used have a high boiling point and are difficult to purify by distillation, and there are problems such as deterioration of lens physical properties and reduction in yield due to oligomer components that are difficult to remove.

Japanese Patent Laid-Open No. 2-270859 JP 2001-114861 A

  The subject of this invention is providing the manufacturing method of the polythiol compound for optical lenses with little content of an oligomer component.

As a result of intensive studies to solve the problems of the present invention, the present inventor has found that the oligomer component contained in the polythiol compound is produced by an oxidation reaction and an intermolecular reaction by thiolate. As a result of further investigation, the above problem was solved by using a base containing hydrazine, which is a weak base and has a reducing property, in the hydrolysis step when producing polythiol via a thuronium salt, and the content of oligomer components is low The present inventors have found that a polythiol compound can be obtained and have completed the present invention.
That is, the present invention is as follows.
1. A step of preparing a thiuonium salt by reacting a polyalcohol and thiourea, a step of hydrolyzing a hydrazine hydrate in the presence of an organic solvent, and a solution obtained in the hydrolysis step. And a step of washing with an acid.
2. The method for producing a polythiol compound according to 1, wherein the produced polythiol compound is a compound having a structure represented by the following formula (1).
3. The method for producing a polythiol compound according to 1 or 2, wherein in the hydrolyzing step, the thiouronium salt is hydrolyzed in the presence of hydrazine hydrate and ammonia.
A polythiol compound obtained by any one of the methods described in 4.1 to 3.
A composition for optical materials, comprising the polythiol compound according to 5.4 and a polyisocyanate compound.

  According to the present invention, it is possible to obtain a polythiol compound having a low oligomer component content.

Hereinafter, the present invention will be described in detail by taking the compound of the formula (1) as an example.
The polyalcohol represented by the following formula (2), which is a raw material of the polythiol compound of the formula (1), is synthesized by reacting epichlorohydrin and 2-mercaptoethanol in the presence of an alkali.
The synthesized polyalcohol is reacted with thiourea in mineral acid, and the obtained thiuonium salt is hydrolyzed with a base containing hydrazine in the presence of an organic solvent to obtain the polythiol represented by the formula (1).

  Specifically, as a method for synthesizing the polythiol compound represented by the formula (1) from the polyalcohol represented by the formula (2), for example, it is performed through a thuronium chloride step and a hydrolysis step as follows. In the thuronium chlorination step, the polyalcohol represented by the formula (2) is equivalent to 3 equivalents or more of the hydroxy group in the molecule and less than 5 equivalents, preferably 2 equivalents, preferably to the hydroxy group. 1.1 equivalents, that is, 3.3 equivalents or more and less than 4 equivalents of thiourea that is 1 equivalent excess with respect to the polyalcohol are added and reacted. If the amount of thiourea is small, the purity of the polythiol obtained is lowered. The reaction is carried out in the range of room temperature to reflux temperature in a mineral acid aqueous solution of 3 equivalents or more, preferably 3 equivalents or more and 6 equivalents or less, relative to the polyalcohol represented by formula (2). As the mineral acid, hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid and the like can be used. Hydrochloric acid is preferable from the viewpoint of obtaining a sufficient reaction rate and controlling the coloring of the product.

Subsequently, the hydrolysis reaction is performed by adding a base containing hydrazine while stirring and mixing the reaction solution and the organic solvent.
The organic solvent is not particularly limited as long as the reaction is allowed to proceed, but preferably ethers, aromatic hydrocarbons and halogenated hydrocarbons are used. Specific examples include diethyl ether, benzene, toluene, xylene, dichloroethane, chloroform, chlorobenzene and the like. Of these, toluene is preferred.
The total molar amount of the base to be used is 1 equivalent or more, preferably 1 equivalent or more and 3 equivalents or less, more preferably 1 equivalent or more 2 with respect to the amount of mineral acid added in the above-mentioned thuronium chlorination step. Add under equal amount to make it alkaline. The reaction temperature in that case is 0 degreeC or more and 80 degrees C or less, Preferably they are 20 degreeC or more and 60 degrees C or less. When the temperature is low, the reaction does not proceed. When the temperature is high, the resulting polythiol is colored.

  The hydrazine used in the hydrolysis step is preferably hydrazine hydrate. When anhydrous hydrazine is used, heat generation is large, which causes coloring. Also, hydrazine and other bases may be used in combination. The base used in combination is preferably an amine, and particularly preferably ammonia. The molar ratio of hydrazine in the base used is 30 to 100%, preferably 50 to 100%, more preferably 70 to 100%. If the proportion of hydrazine is too small, the effect cannot be obtained.

  By adding an organic solvent before adding a base during the hydrolysis step, the effect of hydrolysis with hydrazine can be improved. It is possible to quickly extract the polythiol produced by the coexistence of an organic solvent during the hydrolysis using hydrazine to the organic layer, and to prevent coloring and oligomerization due to side reactions. In addition, hydrazine is a weak base and it is difficult to produce highly reactive thiolates from thiols, so it can prevent coloring and oligomerization as well, and it also has the ability to reduce the formation of disulfides that cause lens coloring. it can.

  The polythiol compound represented by the formula (1) thus generated can be purified by pickling, washing with water, concentrating and filtering after taking out the organic layer.

Specific examples of the acid used in the pickling include nitric acid, hydrochloric acid, sulfuric acid, boric acid, phosphoric acid, acetic acid, peracetic acid, thioacetic acid, oxalic acid, tartaric acid, succinic acid, maleic acid, and the like. Hydrochloric acid and sulfuric acid.
Among them, sulfuric acid of 0.5M to 1M or hydrochloric acid of 1M to 2.5M, preferably 0.5M to 1M sulfuric acid, 1.7M to 2.5M hydrochloric acid, more preferably 0.5M to 1M The following sulfuric acid. In the pickling step, removal of a nitrogen component derived from hydrazine and the like are performed, and the reactivity of the polymerizable composition at the time of resin production is stabilized, thereby reducing the striae of the resin. If the concentration of the acid used is too thin, the cleaning effect is not exhibited. If the concentration is too high, the polythiol compound may be colored or suspended during cleaning.

  Examples of the polythiol compound obtained in the present invention include 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane, bis (2-mercaptoethyl) sulfide, 4,8-dimercaptomethyl-1, 11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11- Dimercapto-3,6,9-trithiaundecane, 2,5-dimercaptomethyl-1,4-dithiane, 1,1,3,3-tetramercaptomethyl-2-thiapropane, bis (2,3-dimercapto Propyl) sulfide, 1,1,1-tris (mercaptomethyl) propane, 1,5,9,13-tetramercapto-3,7,11-trithia Ridecane and tetramercaptomethylmethane, preferably 1,2-bis [(2-mercaptoethyl) thio] -3-mercaptopropane, bis (2-mercaptoethyl) sulfide, more preferably 1,2-bis [ (2-mercaptoethyl) thio] -3-mercaptopropane.

  The polyisocyanate compound used in the present invention is not particularly limited as long as it is a compound having at least two isocyanates in one molecule. Specific examples thereof include diethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexahexan. Methylene diisocyanate, cyclohexane diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, 1,4-bis (isocyanatemethyl) cyclohexane, isophorone diisocyanate, 2,6-bis (isocyanatemethyl) decahydronaphthalene, lysine triisocyanate, tolylene diene Isocyanate, o-tolidine diisocyanate, diphenylmethane diisocyanate, diphenyl ether diisocyanate, 3- (2 ′ -Isocyanatocyclohexyl) propyl isocyanate, isopropylidenebis (cyclohexyl isocyanate), 2,2'-bis (4-isocyanatophenyl) propane, triphenylmethane triisocyanate, bis (diisocyanatotolyl) phenylmethane, 4,4 ', 4' '-Triisocyanate-2,5-dimethoxyphenylamine, 3,3'-dimethoxybenzidine-4,4'-diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diisocyanate biphenyl, 4,4′-diisocyanate-3,3′-dimethylbiphenyl, dicyclohexylmethane-4,4′-diisocyanate, 1,1′-methylenebis (4-isocyanatebenzene), 1,1′-methylenebis (3- Til-4-isocyanatebenzene), m-xylylene diisocyanate, p-xylylene diisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate, 1,3-bis (2-isocyanate-2-propyl) Benzene, 2,6-bis (isocyanatomethyl) naphthalene, 1,5-naphthalene diisocyanate, bis (isocyanatemethyl) tetrahydrodicyclopentadiene, bis (isocyanatemethyl) dicyclopentadiene, bis (isocyanatemethyl) tetrahydrothiophene, bis (isocyanate) Methyl) norbornene, bis (isocyanatomethyl) adamantane, thiodiethyl diisocyanate, thiodipropyl diisocyanate, thiodihexyl diisocyanate Bis [(4-isocyanatemethyl) phenyl] sulfide, 2,5-diisocyanate-1,4-dithiane, 2,5-diisocyanatemethyl-1,4-dithiane, 2,5-diisocyanatemethylthiophene, dithiodiethyl Examples thereof include diisocyanate and dithiodipropyl diisocyanate.

  Among these, preferred examples are isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, m-tetramethylxylylene diisocyanate, p-tetramethylxylylene diisocyanate. 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, bis (isocyanatomethyl) norbornene, and 2,5-diisocyanatomethyl-1,4-dithiane One or more compounds, among which preferred compounds are isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, Xamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, m-xylylene diisocyanate, and more preferred compounds are isophorone diisocyanate, m-xylylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, The most preferred compound is m-xylylene diisocyanate.

However, the polyisocyanate compounds that are the subject of the present invention are not limited to these, and these may be used alone or in admixture of two or more.
The use ratio (molar ratio) of the polyisocyanate compound used in the present invention is not particularly limited, but is usually in the range of NCO / (SH + OH) = 0.7 to 1.5, preferably 0.7 to 1.3. Within the range, more preferably within the range of 0.8 to 1.2.

  When obtaining an optical material by using the polythiol compound synthesized using the present invention, it is preferable to mix a polythiol compound or a polyisocyanate compound with a polymerization catalyst or additives as required.

  Various substances such as known chain extenders, crosslinking agents, light stabilizers, ultraviolet absorbers, antioxidants, oil-soluble dyes, fillers and internal mold release agents may be added depending on the purpose. In order to adjust the reaction rate, a known reaction catalyst used in the production of polythiourethane can be appropriately added. When manufacturing a plastic lens from the composition for optical materials of this invention, it is normally performed by cast polymerization.

  In the manufacturing method of the composition for optical materials of this invention, it is necessary to perform a defoaming process after mixing each component. The defoaming treatment of the optical material composition under suitable conditions in advance before polymerization and curing is due to the effect of the low-boiling components such as carbon dioxide generated by the reaction between moisture contained in the composition and isocyanate groups. This is preferable from the viewpoint of preventing defects such as deterioration of transparency. The degree of vacuum is 0.01 to 50 Torr, preferably 0.01 to 30 Torr, more preferably 0.1 to 10 Torr, and still more preferably 0.1 to 5 Torr.

  The casting solution thus obtained can be purified by filtering impurities and the like immediately before polymerization and curing. It is desirable to further refine the quality of the optical material of the present invention by purifying the optical material composition through a filter to filter impurities and the like. The filter used here has a pore size of about 0.05 to 10 μm, and generally 0.1 to 1.0 μm. As a filter material, PTFE, PET, PP, or the like is preferably used.

  The polymerization temperature and time vary depending on the type of monomer and additives, but are -10 ° C to 160 ° C, usually -10 ° C to 140 ° C. The polymerization can be performed at a predetermined polymerization temperature by holding for a predetermined time, raising the temperature from 0.1 ° C. to 100 ° C./h, lowering the temperature from 0.1 ° C. to 100 ° C./h, and combinations thereof.

  Further, after the polymerization is completed, annealing the material at a temperature of 50 ° C. to 150 ° C. for about 5 minutes to 5 hours is a preferable treatment for removing distortion of the optical material. Furthermore, surface treatments such as dyeing, hard coating, antireflection, antifogging properties, antifouling properties, and imparting impact resistance can be performed as necessary.

EXAMPLES Hereinafter, although a synthesis example, an Example, and a comparative example demonstrate this invention concretely, this invention is not limited only to these Examples. In addition, evaluation of the obtained polythiol compound and resin (optical material) was performed by the following method.
-Content of oligomer component in polythiol The produced polythiol compound was diluted to 1% with chloroform and analyzed by gel permeation chromatography (GPC). The liquid feed pump was Shimadzu LC-6AD, the column was Shodex GPC K-801, the detector was RID-10A, and the analysis was performed by flowing chloroform at 1 mL / min while maintaining the temperature at 40 ° C. in a column oven. The sum of the area% of the peak having a shorter retention time than the polythiol compound as the main component was taken as the content ratio of the oligomer component.
-Oxidation resistance ΔYI of optical material made of thiourethane resin:
A YI value of a resin circular plate having a thickness of 10 mm and φ80 mm before and after heating at 150 ° C. for 1 hour was measured using a spectrocolorimeter JS555 (manufactured by Color Techno System), and the difference was taken as ΔYI.
-Striae occurrence rate of optical material made of thiourethane resin The resin composition for optical material was injected into a lens mold having a diameter of 75 mm and -8D composed of two glass plates and a tape, and was cured by polymerization. After standing to cool, it was released from the mold, annealed, and then visually observed under a high-pressure mercury lamp. 10 sheets are created, “A” indicates that there is no distortion, “B” indicates that there is 1 distortion, “C” indicates that there is 2 distortion, “D” indicates that there is distortion 3 or more. It was. A, B and C are acceptable, but A and B are preferred, and A is particularly preferred.

Synthesis Example (Synthesis of polyalcohol compound and thiuonium chloride reaction)
In a 2 L four-necked reaction flask equipped with a stirrer, reflux condenser, nitrogen gas purge pipe, and thermometer, 76.0 parts by mass of water and 90.0 parts by mass (1.08 mol) of a 48% by mass aqueous sodium hydroxide solution were added. I was charged. At 20 ° C., 169 parts by mass of 2-mercaptoethanol (2.16 mol) was added dropwise over 10 minutes, and then 99.9 parts by mass of epichlorohydrin (1.08 mol) was added at the same temperature for 2 hours. After dropping, the temperature was raised to 30 ° C. and aging was performed for 1 hour.
Next, 450.1 parts by mass (44.44 mol) of 36% by mass hydrochloric acid and 271.7 parts by mass (3.57 mol) of thiourea were charged and heated under reflux at 110 ° C. for 3.5 hours to perform thulonium chloride. It was.

Example 1
The thyronium salt synthesized in the synthesis example was cooled to 50 ° C., 450.0 parts by mass of toluene was added, and then 260 parts by mass (5.20 mol) of hydrazine hydrate was stirred while stirring so that the organic layer and the aqueous layer were uniformly mixed. ) Was carried out for 2 hours to obtain a toluene solution of polythiol containing the compound represented by the formula (1) as a main component. The toluene solution was washed with 400 mL of 0.5 M sulfuric acid aqueous solution and then washed twice with 400 mL of water to remove low-boiling components under reduced pressure at 50 ° C. Then, it filtered and 272.9 mass parts of polythiol compounds which have a compound of Formula (1) as a main component were obtained. Table 1 shows the oligomer content ratio of the obtained polythiol compound.

Manufacture of plastic lenses 52 parts by mass of m-xylylene diisocyanate, 0.015 parts by mass of di-n-butyltin dichloride, 0.1 parts by mass of Zepan UN made by Stepan, and 0.05 parts by mass of Biosorb 583 made by Kyodo Pharmaceutical Mixed and dissolved. At 15 ° C., 48 parts by mass of polythiol containing the compound of the formula (1) synthesized in Example 1 as a main component was added and mixed to obtain a mixed homogeneous liquid. Defoaming was performed for 30 minutes at 600 Pa of this mixed homogeneous liquid. Then, after filtering with a 1 micrometer PTFE filter, it inject | poured into the mold type | mold for -8D which consists of various glass molds and tapes. The mold was put into an oven, gradually heated from 10 ° C. to 120 ° C., and polymerized in 20 hours. After completion of the polymerization, the mold was removed from the oven and released to obtain a resin. The obtained resin was further annealed at 130 ° C. for 2 hours to obtain an optical material (lens) made of thiourethane resin. Table 1 shows ΔYI and striae incidence of the obtained resin.

Examples 2-4
The compound of the formula (1) was used as the main component according to Example 1, except that the total amount of base added in Example 1 was not changed and hydrolysis was carried out by adding hydrazine hydrate and 28% ammonia water in each substance ratio. To obtain polythiol. Table 1 shows the results of manufacturing and evaluating plastic lenses in the same manner using the polythiol.

Examples 5-8
A polythiol having a compound of the formula (1) as a main component was obtained according to Example 1 except that the acid used for the acid cleaning in Example 1 was changed to 400 mL of sulfuric acid or hydrochloric acid of each concentration. Table 1 shows the results of manufacturing and evaluating plastic lenses in the same manner using the polythiol.

Comparative Example 1
A polythiol containing the compound of the formula (1) as a main component was obtained according to Example 1, except that the total amount of base added in Example 1 was not changed and hydrolysis was performed by adding 28% ammonia water. Table 1 shows the results of producing and evaluating a plastic lens using the polythiol in the same manner as the polythiol obtained in Example 1.

Comparative Example 2
In Example 1, the hydrolysis reaction was carried out without adding toluene, and after completion of the reaction, extraction was performed with 450 parts by mass of toluene to obtain a toluene solution of polythiol. According to Example 1, the compound of formula (1) was used as the main component. To obtain polythiol. Table 1 shows the results of manufacturing and evaluating plastic lenses in the same manner using the polythiol.

Comparative Example 3
A polythiol having a compound of the formula (1) as a main component was obtained according to Example 1 except that acid washing was not performed in Example 1 but only water washing. Table 1 shows the results of manufacturing and evaluating plastic lenses in the same manner using the polythiol.

Claims (2)

A step of preparing a thiuonium salt by reacting a polyalcohol with thiourea, a step of hydrolyzing the thiouronium salt with hydrazine hydrate in the presence of an organic solvent, and a solution obtained in the hydrolysis step with an acid. A process for producing a polythiol compound having a washing step ,
The said manufacturing method whose polythiol compound manufactured is a compound which has a structure represented by following (1) Formula .
The method for producing a polythiol compound according to claim 1, wherein, in the hydrolysis step, the thiouronium salt is hydrolyzed in the presence of hydrazine hydrate and ammonia.