Polythiol compositions and optical polymerizable compositions including the same

Abstract

The polythiol composition according to the exemplary embodiment includes: a polythiol-based compound; and a benzyl halide-based reaction modifier in an amount of 10 ppm to 2,000 ppm based on the weight of the polythiol-based compound. The reaction rate of the polythiol-based compound and the isocyanate-based compound can be controlled by the reaction modifier to suppress the streak phenomenon.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0112395, filed with the Korean Intellectual Property Office (KIPO) on September 3, 2020, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to polythiol compositions and optically polymerizable compositions comprising such compositions (“polymerizable compositions for optical materials”). More particularly, this invention relates to polythiol compositions comprising polythiol compounds and other compounds, and polymerizable compositions for optical materials comprising such compositions. Background Technology

[0004] Polythiol compounds are widely used as raw materials, for example, in the manufacture of polyurethane resins. For instance, polythiol compounds are used to manufacture optical lenses using polyurethane resins, and the quality of the polythiol compounds used as raw materials, such as their purity, directly affects the quality of the optical lenses.

[0005] For example, polythiourethane compounds prepared by reacting polythiols and isocyanates can be used as substrates for optical lenses.

[0006] For example, Korean Patent Publication No. 10-1338568 discloses a method for synthesizing polythiol compounds, which involves reacting a polyol compound with thiourea to prepare isothiourea salts, followed by hydrolysis with ammonia.

[0007] Depending on the reactivity of the synthesized polythiol compounds with the isocyanate compounds, the transparency of the lens may decrease, or optical inhomogeneity may result. Furthermore, depending on the extent of the hydrolysis reaction, the optical properties of the lens may change, potentially leading to yellowing, clouding, and other phenomena. Summary of the Invention

[0008] The purpose of the exemplary embodiments is to provide polythiol compositions with improved reactivity and optical properties.

[0009] Another objective according to an exemplary embodiment is to provide a polymeric composition for optical materials, comprising a polythiol composition having improved reactivity and optical properties.

[0010] The polythiol composition according to an exemplary embodiment includes: a polythiol compound; and a benzyl halide reaction modifier in an amount of 10 to 2,000 ppm by weight based on the polythiol compound.

[0011] The polymeric composition for optical materials according to an exemplary embodiment includes: a polythiol compound; an isocyanate compound; and a benzyl halide reaction modifier in an amount of 10 to 2,000 ppm by weight based on the polythiol compound.

[0012] In some embodiments, the polythiol compound may include at least one selected from the group consisting of trifunctional polythiol compounds represented by formula 1 and tetrafunctional polythiol compounds represented by formulas 2-1 to 2-3.

[0013] [Formula 1]

[0014]

[0015] [Equation 2-1]

[0016]

[0017] [Equation 2-2]

[0018]

[0019] [Equation 2-3]

[0020]

[0021] In some embodiments, the reaction modifier may include a benzyl halide, or a benzyl halide derivative represented by formula 3 or formula 4:

[0022] [Formula 3]

[0023]

[0024] [Formula 4]

[0025]

[0026] (Whereinin, in Formulas 3 and 4, X is a halogen element, and R1 and R2 are each independently a halogen element, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, a vinyl group, a nitrile group, an isocyanate group, or an isocyanate alkyl group having 1 to 10 carbon atoms, an aldehyde group, a carboxyl group, an ester group having 1 to 10 carbon atoms, an amino group, a nitro group, an allyl group, an aryl group, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a benzyl group, a peroxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an azide group, a diazo group, a nitrosyl group, a mercapto group, an alkylthio group having 1 to 10 carbon atoms, a sulfonyl group, a sulfinyl group, a sulfonyl group, a thiocyanate group, an isothiocyanate group, a thiocarbonyl group, a phosphinyl group, or a hydroxyl group).

[0027] In some embodiments, the reaction modifier may include at least one of the following: (chloromethyl)benzene, 1-chloro-2-(chloromethyl)benzene, 2,4-dichloro-1-(chloromethyl)benzene, 1-(chloromethyl)-4-(trifluoromethyl)benzene, 1-(chloromethyl)-4-vinylbenzene, 1-bromo-4-(chloromethyl)benzene, 4-bromo-1-(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)benzene, 1-(chloromethyl)-3,5-dimethylbenzene, 1-(chloromethyl)-3-methylbenzene, 3-(chloromethyl)benzonitrile, and 1-(chloromethyl)-3-(isocyanate methyl)benzene.

[0028] In some implementations, the content of the reaction modifier can range from 10 ppm to 1,000 ppm based on the weight of the polythiol compound.

[0029] According to an exemplary embodiment, an optical product comprising a polyurethane resin prepared from a polymeric composition for optical materials is provided.

[0030] According to the above embodiments, the polythiol composition may include a predetermined amount of a benzyl halide compound as a reaction modifier between the polythiol compound and the isocyanate compound. The synthesis reaction rate of the polythiourethane resin can be appropriately controlled by the reaction modifier. Therefore, the polythiol composition can be used to obtain optical products such as lenses that have uniform optical properties and suppress the generation of non-uniformity ("stria").

[0031] Furthermore, the chemical stability of polythiol compositions and optical products can be improved by using reaction modifiers, thereby effectively suppressing lens clouding.

[0032] According to an exemplary embodiment, the formation of disulfide or cyclic sulfide compounds in the composition can be suppressed by a reaction modifier. Therefore, the occurrence of haze in the polythiol composition can be suppressed, and the formation of byproducts such as oligomers in the composition can be prevented. Detailed Implementation

[0033] The embodiments of this application will be described in detail below. In this respect, the invention can be modified in various ways and has various embodiments, such that particular embodiments are described in detail in this disclosure. However, the invention is not limited to the particular embodiments, and those skilled in the art will understand that the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0034] Unless otherwise defined, all terms used herein, including technical and scientific terms, shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0035] According to one aspect of this application, a polythiol composition comprising a polythiol compound and a reaction modifier is provided.

[0036] Polythiol compounds can include trifunctional polythiol compounds and / or tetrafunctional polythiol compounds.

[0037] Non-limiting examples of trifunctional polythiol compounds may include compounds represented by Formula 1 below.

[0038] [Formula 1]

[0039]

[0040] Trifunctional polythiols can be synthesized, for example, from polyols obtained by reacting with 2-mercaptoethanol and epihaloethanol.

[0041] Under acidic conditions, polyol compounds react with thiourea to form thiourea salts, which can then be hydrolyzed under alkaline conditions to prepare trifunctional polythiool compounds.

[0042] The synthesis method can be illustrated by Scheme 1 below.

[0043] [Option 1]

[0044]

[0045] According to one embodiment, in the reaction step of epihaloalcohol and 2-mercaptoethanol used to synthesize trifunctional polythiol compounds, a metal-containing catalyst such as sodium hydroxide or potassium hydroxide can be used.

[0046] Non-limiting examples of tetrafunctional polythiols may include compounds represented by formulas 2-1 to 2-3 below.

[0047] [Equation 2-1]

[0048]

[0049] [Equation 2-2]

[0050]

[0051] [Equation 2-3]

[0052]

[0053] Tetrafunctional polythiols can be synthesized from, for example, polyols obtained by reacting with 2-mercaptoethanol and epihaloethanol.

[0054] Polyols can react with metal sulfides to generate tetrafunctional polyol intermediates. After the tetrafunctional polyol intermediate reacts with thiourea under acidic conditions to produce thiourea salts, tetrafunctional polythiools can be prepared by hydrolysis under alkaline conditions.

[0055] The above-mentioned synthetic hydrolysis can be illustrated by the following scheme 2.

[0056] [Option 2]

[0057]

[0058] In one embodiment, a basic catalyst may be used in the reaction step involving the epihaloalcohol and 2-mercaptoethanol for the synthesis of a tetrafunctional polythiol compound. Examples of basic catalysts may include tertiary amines such as triethylamine, quaternary ammonium salts, triphenylphosphine, and trivalent chromium compounds.

[0059] As illustrated in schemes 1 and 2 above, epichlorohydrin can be used as an epihalohydrin.

[0060] In schemes 1 and 2, reflux under acidic conditions can be used to generate isothiourea salts via reaction with thiourea. To create these acidic conditions, acidic compounds such as hydrochloric acid, hydrobromic acid, iodic acid, sulfuric acid, and phosphoric acid can be used.

[0061] As described above, after the formation of isothiourea salt, trifunctional or tetrafunctional polythiols can be prepared by hydrolysis under alkaline conditions. For example, it can be hydrolyzed by adding an alkaline aqueous solution to the reaction solution containing isothiourea salt.

[0062] In some embodiments, the alkaline aqueous solution may include strongly alkaline compounds, such as alkali metal hydroxides, alkaline earth metal hydroxides and / or alkali metal hydrides, such as NaOH, KOH, LiOH, Ca(OH)2, LiH, NaH, etc.

[0063] According to an exemplary embodiment, an organic solvent may be added prior to the addition of an alkaline aqueous solution. An organic solvent with low or substantially no reactivity and a boiling point above the thiolation reaction temperature may be used to ensure stable thiolation.

[0064] Considering the toxicity of the solvent, toluene is preferred as the organic solvent.

[0065] The polythiol compounds obtained as described above can be further purified. For example, by repeatedly performing acid washing and water washing processes, impurities included in the polythiol compounds can be removed, and the transparency of optical materials prepared from the polythiol compositions can be improved. Afterwards, further drying, filtration, etc., can be performed.

[0066] In one embodiment, after hydrolysis, the aqueous layer can be separated or removed by layer separation. Acid washing can be performed for 20 minutes to 1 hour or 20 minutes to 40 minutes at a temperature of about 20°C to 50°C, preferably about 30°C to 40°C, by introducing an acid solution into the obtained organic phase solution.

[0067] After pickling, a water washing process can be performed by adding deaerated water with a dissolved oxygen concentration adjusted to below 5 ppm, preferably below 3 ppm, and more preferably below 2 ppm. The water washing process can be carried out at a temperature of about 20°C to 50°C, preferably about 35°C to 45°C, for 20 minutes to 1 hour, or 20 minutes to 40 minutes. The water washing process can be repeated more than twice, for example, 3 to 6 times.

[0068] After pickling and washing, residual organic solvents and moisture are removed by heating under reduced pressure, and then the mixture is filtered to obtain high-purity polythiol compounds.

[0069] According to exemplary embodiments, the polythiol composition may further include a benzyl halogen reaction modifier. In one embodiment, the polythiol composition may include a benzyl chloride reaction modifier.

[0070] The reaction modifier may include benzyl halides, or benzyl halide derivatives represented by Formula 3 or Formula 4 below.

[0071] [Formula 3]

[0072]

[0073] [Formula 4]

[0074]

[0075] In Formulas 3 and 4, X is a halogen element (F, Cl, Br, or I). Furthermore, R1 and R2 can each independently be a halogen, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 3 carbon atoms, a vinyl group, a nitrile group, an isocyanate group, an isocyanate alkyl group having 1 to 3 carbon atoms, an aldehyde group, a carboxyl group, an ester group having 1 to 10 carbon atoms, an amino group, a nitro group, an allyl group, an aryl group, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a benzyl group, a peroxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an azide group, a diazo group, a nitroso group, a mercapto group, an alkylthio group having 1 to 10 carbon atoms, a sulfonyl group, a sulfinyl group, a sulfonyl group, a thiocyanate group, an isothiocyanate group, a thiocarbonyl group, a phosphinyl group, or a hydroxyl group.

[0076] Examples of benzyl halide derivatives may include: (chloromethyl)benzene, 1-chloro-2-(chloromethyl)benzene, 2,4-dichloro-1-(chloromethyl)benzene, 1-(chloromethyl)-4-(trifluoromethyl)benzene, 1-(chloromethyl)-4-vinylbenzene, 1-bromo-4-(chloromethyl)benzene, 4-bromo-1-(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)benzene, 1-(chloromethyl)-3,5-dimethylbenzene, 1-(chloromethyl)-3-methylbenzene, 3-(chloromethyl)benzonitrile, and 1-(chloromethyl)-3-(isocyanate methyl)benzene, etc. These may be used alone or in combination of two or more thereof.

[0077] Reaction modifiers can be used as regulators to control the reaction rate between polythiol compounds contained in polythiol compositions and isocyanate compounds contained in polymeric compositions for optical materials.

[0078] For example, when the reaction rate between polythiol compounds and isocyanate compounds increases excessively, the fluidity of the synthesized polythiourethane resin increases, leading to phenomena such as inhomogeneity of the refractive index and striations in lenses.

[0079] However, according to an exemplary embodiment, the synthesis reaction rate of polythiourethane can be appropriately suppressed by a reaction modifier contained in the polythiol composition. Therefore, optical products such as lenses can be obtained using the polythiol composition, which possess uniform optical properties and suppress the generation of streaks.

[0080] In addition, reaction modifiers can improve the chemical stability of optical products, thereby effectively suppressing lens clouding.

[0081] Reaction modifiers can provide inhibitors for the formation of disulfide or cyclic sulfide compounds in polythiol compositions.

[0082] For example, thiol radicals or anions can be generated during the synthesis of polythiol compounds, and these radicals or anions can react with each other to produce disulfide byproducts. In this case, the amount of high molecular weight byproducts such as oligomers in the polythiol composition can be increased to improve viscosity.

[0083] In addition, disulfide or cyclic sulfide compounds can increase the haze of polythiol compositions, thereby causing opacity, cloudiness, etc. in optical lenses.

[0084] The production of disulfide or cyclic sulfide compounds can be promoted under alkaline conditions. However, according to an exemplary embodiment, the composition or the atmosphere used to produce the composition can be maintained under acidic conditions by a reaction modifier, and the formation of disulfide or cyclic sulfide compounds can be suppressed.

[0085] Therefore, even when the haze of the polythiol composition is reduced and a separate filtration process for removing the haze of the polythiol composition is omitted, the cloudiness and opacity of the optical lens can be sufficiently suppressed.

[0086] Furthermore, the reduction of high molecular weight byproducts such as oligomers in the polythiol composition inhibits the increase in viscosity of the composition and can also improve the efficiency of the urethane reaction with isocyanate compounds.

[0087] In some embodiments, the content of disulfide or cyclic sulfide compounds in the polythiol composition may be less than 1 wt.%, preferably less than 0.1 wt.%, and more preferably less than 0.01 wt.%, based on the weight of the polythiol compound.

[0088] According to an exemplary embodiment, the content of the reaction modifier can be in the range of 10 ppm to 2,000 ppm based on the weight of the polythiol compound.

[0089] Within the aforementioned range, yellowing caused by reduced purity of the polythiol composition is suppressed, while maintaining an appropriate reaction rate for the synthesis of polythiourethane resin, thereby preventing streaks and cloudiness in optical products.

[0090] Furthermore, the formation of byproducts such as disulfides or cyclic sulfides can be suppressed, thereby improving the purity and yield of polysulfuric esters.

[0091] In a preferred embodiment, the content of the reaction modifier, based on the weight of the polythiol compound, can range from 10 ppm to 1,000 ppm. More preferably, the content of the reaction modifier, based on the weight of the polythiol compound, can range from 10 ppm to 500 ppm, or from 10 ppm to 300 ppm.

[0092] In some embodiments, a strongly basic compound can be used during the hydrolysis reaction under the aforementioned alkaline conditions. For example, when toluene is used as the organic solvent, a benzyl halide is generated via a side reaction of toluene and can be added to the reaction modifier. In this case, the content of the reaction modifier will exceed a predetermined range.

[0093] However, for example, by using the aforementioned strong basic compounds instead of weak basic compounds such as ammonia, amines, and pyridine, the benzyl halide produced by the side reaction of toluene can be sufficiently removed by hydrolysis. Therefore, while maintaining the content of the reaction modifier within the target range, the suppression of the aforementioned streaks and improvement in storage can be effectively achieved.

[0094] In one embodiment, as a strongly basic compound, pK measured at 25°C can be used. b Alkaline compounds with a value below 4.

[0095] According to one aspect of this application, a polymeric composition for optical materials comprising the above-described polythiol composition is provided.

[0096] Polymer compositions for optical materials may include polythiol compositions and isocyanate compounds.

[0097] Isocyanate compounds may include compounds that can be used as monomers in the synthesis of polythiourethanes. In preferred embodiments, isocyanate compounds may include 1,3-bis(isocyanate-methyl)cyclohexane, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, and toluene diisocyanate, etc. These may be used alone or in combination of two or more thereof.

[0098] Polymer compositions for optical materials may further include additives such as release agents, reaction catalysts, heat stabilizers, ultraviolet absorbers, and bluing agents.

[0099] Examples of release agents may include fluorinated nonionic surfactants having perfluoroalkyl, hydroxyalkyl, or phosphate groups; organosilicon nonionic surfactants having dimethylpolysiloxane, hydroxyalkyl, or phosphate groups; alkyl quaternary ammonium salts, such as trimethylhexadecylammonium salt, trimethylstearylammonium salt, dimethylethylhexadecylammonium salt, triethyldodecylammonium salt, trioctylmethylammonium salt, and diethylcyclohexyldodecylammonium salt; and acidic phosphate esters, etc. These may be used alone or in combination of two or more thereof.

[0100] As reaction catalysts, catalysts used in the polymerization reaction of polysulfururethane resins can be used. For example, dialkyltin halide catalysts such as dibutyltin dichloride and dimethyltin dichloride; dialkyltin dicarboxylate catalysts such as dimethyltin diacetate, dibutyltin dioctanoate, and dibutyltin dilaurate; alkoxydialkyltin catalysts such as dibutoxydibutyltinane and dibutoxydioctyltinane; dithioalkoxydialkyltin salt catalysts such as di(thiobutoxy)dibutyltin; dialkyltin oxide catalysts such as di(2-ethylhexyl)tin oxide, dioctyltin oxide, and bis(butoxydibutyltin) oxide; and dialkyltin sulfide catalysts, etc. These can be used alone or in combination of two or more.

[0101] Examples of UV absorbers include compounds based on benzophenone, benzotriazole, salicylates, cyanoacrylates, and N,N'-oxalyldiphenylamine. Examples of heat stabilizers include compounds based on metal fatty acids, phosphorus, lead, and organotin compounds. These can be used alone or in combination of two or more of them.

[0102] Bluing agents may be included as color control agents in optical materials prepared from polyurethane resins. For example, a bluing agent may have an absorption band in the visible light region ranging from orange to yellow wavelengths.

[0103] Examples of bluing agents can include dyes, fluorescent whitening agents, fluorescent pigments, and inorganic pigments, and can be appropriately selected based on the physical properties or resin color required for manufacturing optical products. When using dyes as bluing agents, for example, dyes with a maximum absorption wavelength of 520 nm to 600 nm, preferably 540 nm to 580 nm, can be used. Preferably, anthraquinone dyes can be used.

[0104] Polythiourethane resins can be produced by the polymerization reaction of polythiool compounds contained in the polythiool composition with isocyanate compounds, and the polymerization rate can be adjusted or controlled by the reaction modifier contained in the polythiool composition.

[0105] Therefore, it can prevent yellowing or cloudiness, suppress the formation of streaks, and manufacture optical products in which uniformity and improved optical properties are maintained for a long time.

[0106] In some embodiments, based on the total weight of the polymeric composition for optical materials, a polythiol compound may be included in an amount of about 40 wt.% to 60 wt.%, an isocyanate compound may be included in an amount of about 40 wt.% to 60 wt.%, and an additive may be included in an amount of about 0.01 wt.% to 1 wt.%. As mentioned above, a benzyl halogen reaction modifier may be included in an amount of about 10 ppm to 2,000 ppm based on the weight of the polythiol compound. In some embodiments, a benzyl halogen reaction modifier may be included in an amount of about 5 ppm to 1,000 ppm based on the total weight of the polymeric composition for optical materials.

[0107] As described above, the reaction modifier can be included in the polythiol composition, and therefore can be included together with the polythiol composition in the polymerizable composition for optical materials. In one embodiment, the reaction modifier can be added to a composition containing an isocyanate compound, thereby being included in the polymerizable composition for optical materials. In one embodiment, the reaction modifier can be mixed with a polythiol compound and an isocyanate compound, thereby being included in the polymerizable composition for optical materials.

[0108] In some embodiments, the reaction rate of the optical composition involved in Formula 1 below can be maintained in the range of 0.17 to 0.30 by using a reaction modifier. For example, when a trifunctional polythiol compound is used, the reaction rate can be maintained in the range of 0.24 to 0.30, and preferably 0.27 to 0.30. When a tetrafunctional polythiol compound is used, the reaction rate can be maintained in the range of 0.17 to 0.25, and preferably 0.20 to 0.24.

[0109] According to one aspect of this application, an optical product manufactured using the aforementioned optical material and a polymeric composition can be provided.

[0110] For example, after degassing the optical material with a polymeric composition under reduced pressure, the resulting composition can be injected into a mold used to shape the optical material. Mold injection can be performed, for example, in a temperature range of 20°C to 40°C, preferably 20°C to 35°C.

[0111] After injection molding, the temperature can be gradually increased to allow the polymerization reaction of the polyurethane resin to proceed. The polymerization temperature can be in the range of 20°C to 150°C, and preferably in the range of 25°C to 125°C. For example, the maximum polymerization temperature can be in the range of 100°C to 150°C, preferably in the range of 110°C to 140°C, and more preferably in the range of 115°C to 130°C.

[0112] The heating rate can be from 1°C / min to 10°C / min, preferably from 3°C / min to 8°C / min, and more preferably from 4°C / min to 7°C / min. The polymerization time can be from 10 hours to 20 hours, and preferably from 15 hours to 20 hours.

[0113] For example, by appropriately controlling the reaction rate within the above temperature range, lenses with uniform optical and mechanical properties can be easily obtained.

[0114] After polymerization, the polymerized polyurethane resin can be separated from the mold to obtain an optical product. In one embodiment, after separation from the mold, a curing process can be further performed. The curing process can be carried out for about 1 hour to 10 hours, preferably 2 hours to 8 hours, and more preferably 3 hours to 6 hours, within the range of 100°C to 150°C, preferably 110°C to 140°C, more preferably 115°C to 130°C.

[0115] Depending on the shape of the mold, optical products can be manufactured in the form of eyeglass lenses, camera lenses, light-emitting diodes, etc.

[0116] The refractive index of an optical product can be adjusted according to the type and / or content ratio of polythiol compounds and isocyanate compounds used in the polymeric composition for optical materials. For example, the refractive index of an optical product can be adjusted in the range of 1.56 to 1.78, 1.58 to 1.76, 1.60 to 1.78, or 1.60 to 1.76, preferably in the range of 1.65 to 1.75 or 1.69 to 1.75.

[0117] The color index (yellowness index (YI)) of the optical product according to Formula 1 described below can be 24 or less (e.g., 20 to 24), preferably 23 or less, and more preferably 22 or less, or 21 or less.

[0118] Optical products can be improved by further surface treatments such as antifouling, coloring, hard coating, surface polishing, and hardening.

[0119] The embodiments provided in this application will be further described below with reference to specific experimental examples. However, the following experimental examples are merely illustrative of the invention and are not intended to limit the appended claims, and those skilled in the art will clearly understand that various changes and modifications are possible within the scope and spirit of the invention. Such changes and modifications are suitably included in the appended claims.

[0120] Preparation Example

[0121] 1) Preparation Example 1: Synthesis of trifunctional polythiol compounds

[0122] Add 200 parts by weight (“wt. parts”) of 2-mercaptoethanol, 200 wt. parts of degassed water (dissolved oxygen concentration of 2 ppm), and 61.4 wt. parts of sodium hydroxide to the reactor. Slowly add 118.4 wt. parts of epichlorohydrin dropwise to the reactor at 9°C to 13°C, and stir for 3 hours.

[0123] Then, 360.5 wt. parts of thiourea and 666.8 wt. parts of hydrochloric acid with a purity of 36% were added, and the mixture was stirred for 3 hours under reflux at 110°C to carry out the thiourea chlorination reaction.

[0124] After cooling the resulting reaction solution to 45°C, 589.7 wt. parts of toluene were added and the solution was cooled again to 26°C. Then, 829 wt. parts of 33 wt.% sodium hydroxide were added over 25 minutes at 25°C to 45°C, followed by hydrolysis at 40°C to 60°C for 3 hours.

[0125] Then, after 1 hour of layer separation, the aqueous layer was discarded, and 234 wt. parts of 36% hydrochloric acid were added to the obtained toluene solution, followed by a single acid wash at 33°C to 40°C for 30 minutes. After acid washing, 530 wt. parts of degassed water (dissolved oxygen concentration of 2 ppm) were added, and the solution was washed four times at 35°C to 45°C, each wash lasting 30 minutes. After removing toluene and residual water under heating and reduced pressure, 260 wt. parts of the trifunctional polythiol compound represented by Formula 1 were obtained by filtration through a PTFE membrane filter under reduced pressure.

[0126] 2) Preparation Example 2: Synthesis of Tetrafunctional Polythiol Compounds

[0127] After introducing 60.0 wt. parts of water, 0.3 wt. parts of triethylamine, and 73.0 wt. parts of 2-mercaptoethanol into the reactor, the reactor temperature was lowered to 0°C, and 88.2 wt. parts of epichlorohydrin were slowly added dropwise at a temperature below 15°C, followed by further stirring at 30°C for 3 hours. Then, 145.8 wt. parts of a 25% sodium sulfide aqueous solution were slowly added dropwise at 20°C to 25°C, followed by stirring for another 3 hours.

[0128] Then, 473.2 wt. parts of 36% hydrochloric acid and 177.8 wt. parts of thiourea were introduced, and the mixture was stirred for 3 hours under reflux at 110°C to carry out the thiourea salting reaction.

[0129] After cooling the resulting reaction solution to 50°C, 305.6 wt. parts of toluene and 332.6 wt. parts of 50% NaOH were added, and then hydrolysis was carried out at 40°C to 60°C for 3 hours.

[0130] Then, after 1 hour of layer separation, the aqueous layer was discarded, and 120 wt. parts of 36% hydrochloric acid were added to the resulting toluene solution, followed by a single acid wash at 33°C to 40°C for 30 minutes. After acid washing, 250 wt. parts of degassed water (dissolved oxygen concentration of 2 ppm) were added, and the solution was washed four times at 35°C to 45°C, each wash lasting 30 minutes. After removing toluene and residual water under heating and reduced pressure, the solution was filtered through a PTFE membrane filter under reduced pressure to obtain 140 wt. parts of the tetrafunctional polythiol compound represented by Formula 2-1 above.

[0131] Examples and Comparative Examples

[0132] The polythiol compositions of the examples and comparative examples were prepared by adding benzyl chloride as a reaction regulator in amounts relative to the amount of polythiol compounds, as shown in Table 1 below.

[0133] Preparation of polymeric compositions for optical materials and manufacture of lenses

[0134] 1) After receiving the polythiol compositions of the Examples and Comparative Examples, containing 48.0 wt. parts of the trifunctional polythiol of Preparation Example 1, the received compositions were uniformly mixed with 52.0 wt. parts of xylene diisocyanate, 0.012 wt. parts of dibutyltin chloride, and 0.1 wt. parts of a phosphate release agent manufactured by ZELEC® UN tepan. Subsequently, a defoaming process was performed at 600 Pa for 1 hour to prepare a polymeric composition for optical materials.

[0135] The composition, filtered through a 3μm Teflon filter, was then injected into a mold containing a glass mold and adhesive tape. The mold temperature was slowly increased from 25°C to 120°C at a rate of 5°C / min, and polymerization was carried out at 120°C for 18 hours. After polymerization, the mold was separated, and the product was further cured at 120°C for 4 hours to produce lens samples.

[0136] 2) After receiving the polythiol compositions of the Examples and Comparative Examples to prepare the tetrafunctional polythiol of Example 2 by comprising 49.0 wt. parts, the received compositions were uniformly mixed with 51.0 wt. parts xylene diisocyanate, 0.012 wt. parts dibutyltin chloride, and 0.1 wt. parts phosphate release agent manufactured by ZELEC® UN Stepan Corporation. Subsequently, a defoaming process was performed at 600 Pa for 1 hour to prepare a polymeric composition for optical materials.

[0137] The composition, filtered through a 3μm Teflon filter, was then injected into a mold containing a glass mold and adhesive tape. The mold temperature was slowly increased from 25°C to 120°C at a rate of 5°C / min, and polymerization was carried out at 120°C for 18 hours. After polymerization, the mold was separated, and the product was further cured at 120°C for 4 hours to produce lens samples.

[0138] Experimental Example

[0139] (1) Evaluation of storage stability

[0140] After storing the polythiol compositions of the examples and comparative examples at 45°C for 1 year, the composition storage solutions were visually observed and evaluated as follows.

[0141] ○: Completely transparent

[0142] △: Yellowing phenomenon observed

[0143] ×: Haze (stripes) pattern observed

[0144] (2) Evaluation of stripes

[0145] As described above, lens samples with a diameter of 75 mm and a polarization of -4.00 D were prepared using the polymerizable compositions according to the various embodiments and comparative examples. Light from a mercury lamp light source was transmitted through the prepared lens samples, and the transmitted light was projected onto a white board to determine the presence or absence of stripes based on the presence or absence of contrast. The evaluation criteria are as follows.

[0146] ○: No stripes observed

[0147] △: Fine partial stripes were observed.

[0148] X: Stripes are clearly visible to the naked eye.

[0149] (3) Evaluation of lens opacity

[0150] For the lens samples of the embodiments and comparative examples prepared as described above, each sample was illuminated in a dark room with a right beam from a projector, and the presence of haze or opaque material in the lens was visually confirmed.

[0151] The evaluation criteria are as follows.

[0152] ○: No fog

[0153] △: Partial haze observed

[0154] X: The overall haze was clearly observed.

[0155] (4) Measurement of polymerization rate (reactivity slope)

[0156] Using an EMS-1000 (KEM) non-contact viscometer, the standard viscosity (standard cps) was first confirmed using a viscosity standard solution (Brookfield, 1000 cps, 25°C). Subsequently, the viscosity of the polymerizable compositions according to the examples and comparative examples was measured at 10°C for 24 hours. Using the measured values, a mathematical formula (“mathematicalization”) was performed with time on the X-axis and viscosity on the Y-axis, while the Y-axis was converted to a logarithmic scale as shown in Equation 1 below, from which the reaction rate was derived.

[0157] [Mathematical Expression 1]

[0158] Y = a × exp(b × X)

[0159] In Formula 1, the value of 'a' represents the initial viscosity (cps), while the value of 'b' represents the reaction rate. The measured values ​​are rounded to two decimal places.

[0160] (5) Measurement of color index (yellow index (YI))

[0161] For the lens samples of the examples and comparative examples, YI was measured using a colorimeter (Shinko, Colormate). Specifically, lens samples with a thickness of 9 mm and a φ75 mm were prepared, and the chromaticity coordinates x and y were measured. YI was calculated based on the measured values ​​of x and y using Equation 1 below.

[0162] [Formula 1]

[0163] YI = (234 × x + 106 × y + 106) / y (1)

[0164] The evaluation results are shown in Table 1 below.

[0165] [Table 1]

[0166]

[0167] Referring to Table 1, a highly transparent lens with reduced cloudiness and prevented streaking was manufactured by using a polythiol composition from the examples that included benzyl chloride as a reaction modifier within the above-mentioned predetermined content range.

Claims

1. A polythiol composition comprising: Polythiol compounds; and Based on the amount of benzyl halide reaction modifier in the polythiol compound, ranging from 10 ppm to 2,000 ppm by weight, and The content of the cyclic sulfide compound in the polythiol composition is less than 1% by weight based on the weight of the polythiol compound. The polythiol compounds mentioned above include at least one selected from the group consisting of trifunctional polythiol compounds represented by formula 1 and tetrafunctional polythiol compounds represented by formulas 2-1 to 2-3: [Formula 1] [Equation 2-1] [Equation 2-2] [Equation 2-3] ,and The reaction modifiers mentioned above include benzyl halides, or benzyl halide derivatives represented by formula 3 or formula 4: [Formula 3] [Formula 4] In Formulas 3 and 4, X is a halogen element, and R1 and R2 are each independently a halogen element, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, a nitrile group, an isocyanate group, or an isocyanate alkyl group having 1 to 10 carbon atoms, an aldehyde group, a carboxyl group, an ester group having 1 to 10 carbon atoms, an amino group, a nitro group, an aryl group, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a peroxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an azide group, a diazo group, a nitrosyl group, a mercapto group, an alkylthio group having 1 to 10 carbon atoms, a sulfonyl group, a sulfinyl group, a sulfonyl group, a thiocyanate group, an isothiocyanate group, a thiocarbonyl group, a phosphinyl group, or a hydroxyl group.

2. The polythiol composition according to claim 1, wherein, In Formulas 3 and 4, R1 and R2 are each independently vinyl, allyl, or benzyl.

3. The polythiol composition according to claim 1 or 2, wherein the reaction modifier comprises at least one selected from the group consisting of: (chloromethyl)benzene, 1-chloro-2-(chloromethyl)benzene, 2,4-dichloro-1-(chloromethyl)benzene, 1-(chloromethyl)-4-(trifluoromethyl)benzene, 1-(chloromethyl)-4-vinylbenzene, 1-bromo-4-(chloromethyl)benzene, 4-bromo-1-(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)benzene, 1-(chloromethyl)-3,5-dimethylbenzene, 1-(chloromethyl)-3-methylbenzene, 3-(chloromethyl)benzonitrile, and 1-(chloromethyl)-3-(isocyanate methyl)benzene.

4. The polythiol composition according to claim 1 or 2, wherein the content of the reaction regulator is in the range of 10 ppm to 1,000 ppm based on the weight of the polythiol compound.

5. A polymeric composition for optical materials, comprising: Polythiol compounds; Isocyanate compounds; and Based on the amount of benzyl halide reaction modifier in the polythiol compound, ranging from 10 ppm to 2,000 ppm by weight, and The content of the cyclic sulfide compound in the polymeric composition is less than 1% by weight based on the weight of the polythiol compound. The polythiol compounds mentioned above include at least one selected from the group consisting of trifunctional polythiol compounds represented by formula 1 and tetrafunctional polythiol compounds represented by formulas 2-1 to 2-3: [Formula 1] [Equation 2-1] [Equation 2-2] [Equation 2-3] ,and The reaction modifiers mentioned above include benzyl halides, or benzyl halide derivatives represented by formula 3 or formula 4: [Formula 3] [Formula 4] In Formulas 3 and 4, X is a halogen element, and R1 and R2 are each independently a halogen element, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 10 carbon atoms, a nitrile group, an isocyanate group, or an isocyanate alkyl group having 1 to 10 carbon atoms, an aldehyde group, a carboxyl group, an ester group having 1 to 10 carbon atoms, an amino group, a nitro group, an aryl group, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a peroxy group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an azide group, a diazo group, a nitrosyl group, a mercapto group, an alkylthio group having 1 to 10 carbon atoms, a sulfonyl group, a sulfinyl group, a sulfonyl group, a thiocyanate group, an isothiocyanate group, a thiocarbonyl group, a phosphinyl group, or a hydroxyl group.

6. The polymeric composition for optical materials according to claim 5, wherein, In Formulas 3 and 4, R1 and R2 are each independently vinyl, allyl, or benzyl.

7. The polymerizable composition for optical materials according to claim 5 or 6, wherein the reaction modifier comprises at least one selected from the group consisting of: (chloromethyl)benzene, 1-chloro-2-(chloromethyl)benzene, 2,4-dichloro-1-(chloromethyl)benzene, 1-(chloromethyl)-4-(trifluoromethyl)benzene, 1-(chloromethyl)-4-vinylbenzene, 1-bromo-4-(chloromethyl)benzene, 4-bromo-1-(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)-2-fluorobenzene, 1,3-bis(chloromethyl)benzene, 1-(chloromethyl)-3,5-dimethylbenzene, 1-(chloromethyl)-3-methylbenzene, 3-(chloromethyl)benzonitrile, and 1-(chloromethyl)-3-(isocyanate methyl)benzene.

8. The polymerizable composition for optical materials according to claim 5 or 6, wherein the content of the reaction modifier is in the range of 10 ppm to 1,000 ppm based on the weight of the polythiol compound.

9. An optical product comprising a polyurethane resin prepared from a polymerizable composition of an optical material according to claim 5 or 6.

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