Polythiol compositions, optical compositions, and optical products

Abstract

The polythiol composition according to the exemplary embodiment includes a first polythiol compound providing a maximum peak in a high performance liquid chromatography (HPLC) analysis spectrum obtained at a wavelength of 230 nm, and a second polythiol compound represented by S6 having a molecular weight greater than that of the first polythiol compound and being represented by C9H 20 S6 represents a second polythiol compound. The ratio of the peak area of the second polythiol compound to that of the first polythiol compound measured by the HPLC analysis spectrum at a wavelength of 230 nm is 0.05% to 5.0%.

Description

Technical Field

[0001] This invention relates to polythiol compositions, optical compositions, and optical products. More specifically, this invention relates to polythiol compositions comprising a variety of thiol compounds, optical compositions comprising polythiol compounds, and optical products formed from said optical compositions. Background Technology

[0002] 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.

[0003] For example, polythiourethane compounds prepared by reacting polythiols and isocyanates can be used as substrates for optical lenses.

[0004] 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 isothiouronium salt, and then hydrolyzing it with ammonia.

[0005] Depending on the reactivity of the synthesized polythiol compound with the isocyanate compound, the transparency of the lens may decrease, or optical inhomogeneity may result. Furthermore, depending on the physical properties of the polythiol compound, such as its molecular weight and the number of functional groups, the mechanical and optical properties of the lens may be altered. Summary of the Invention

[0006] One objective of the exemplary embodiments is to provide polythiol compositions with improved reactivity and optical properties, and methods for preparing the same.

[0007] One objective of the exemplary embodiments is to provide an optical composition comprising a polythiol composition having improved reactivity and optical properties.

[0008] One objective of the exemplary embodiments is to provide an optical product manufactured using the above-described optical composition.

[0009] According to one aspect of the present invention, a polythiol composition is provided, comprising: a first polythiol compound providing a maximum peak in a high-performance liquid chromatography (HPLC) chromatogram obtained at a wavelength of 230 nm; and a molecular weight greater than that of the first polythiol compound and composed of C9H... 20 S6 represents the second polythiol compound, wherein the ratio of the peak area of ​​the second polythiol compound to the peak area of ​​the first polythiol compound, as measured by HPLC analysis at a wavelength of 230 nm, is 0.05% to 5.0%.

[0010] In some implementations, the first polythiol compound may include a trifunctional polythiol compound.

[0011] In some embodiments, the second polythiol compound may include a trifunctional polythiol compound with a molecular weight greater than that of the first polythiol compound.

[0012] In some embodiments, the first polythiol compound may be represented by the following formula 1:

[0013] [Formula 1]

[0014] .

[0015] In some implementations, the second polythiol compound can be represented by the following formula 2:

[0016] [Equation 2]

[0017] .

[0018] According to another aspect of the present invention, an optical composition comprising an isocyanate compound and a polythiol composition is provided. The polythiol composition comprises: a first polythiol compound providing a maximum peak in a high-performance liquid chromatography (HPLC) chromatogram obtained at a wavelength of 230 nm, and a compound with a molecular weight greater than that of the first polythiol compound and composed of C9H... 20 S6 represents the second polythiol compound. The ratio of the peak area of ​​the second polythiol compound to the peak area of ​​the first polythiol compound, as measured by HPLC analysis at a wavelength of 230 nm, is 0.05% to 5.0%.

[0019] In some embodiments, the first polythiol compound may include a trifunctional polythiol compound, and the second polythiol compound may include a trifunctional polythiol compound with a molecular weight greater than that of the first polythiol compound.

[0020] In some embodiments, the first polythiol compound may be represented by formula 1, and the second polythiol compound may be represented by formula 2:

[0021] [Formula 1]

[0022]

[0023] [Equation 2]

[0024] .

[0025] According to another aspect of the present invention, an optical product comprising a polythiourethane resin prepared from a polythiol composition or a polymerizable composition is provided.

[0026] In some implementations, the glass transition temperature of the optical product can be greater than 86°C.

[0027] In some implementations, the glass transition temperature of the optical product can be in the range of 87°C to 92°C.

[0028] According to the above embodiments, the polythiol composition may include, for example, a first polythiol compound comprising a trifunctional polythiol compound, and a second polythiol compound having a molecular weight or carbon number greater than that of the first polythiol compound. The inclusion of the second polythiol compound within a predetermined range allows the reaction rate of the first polythiol compound to be adjusted within an appropriate range, and the glass transition temperature of the composition can be increased.

[0029] Therefore, the mechanical durability of optical lenses made from polythiol compositions can be improved, and optical defects such as streaks or cloudiness can be suppressed.

[0030] In some embodiments, the content of the second polythiol compound can be finely adjusted to the desired range by adding 2-mercaptoethanol during reflux during the synthesis of the first polythiol compound. Detailed Implementation

[0031] 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 illustrated in the accompanying drawings and 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.

[0032] 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.

[0033] According to one aspect of the present invention, a polythiol composition comprising a plurality of polythiol compounds is provided. The polythiol composition may include a first polythiol compound and a second polythiol compound.

[0034] The first polythiol compound may include the polythiol compound used as a base material in the polythiol compositions or optical compositions described below. The first polythiol compound may be included as the main polythiol compound in the polythiol composition.

[0035] According to an exemplary embodiment, the first polythiol compound may refer to the compound that provides the maximum peak in the high performance liquid chromatography (HPLC) analysis spectrum of the polythiol composition.

[0036] The first polythiol compound may include a trifunctional polythiol compound. As a non-limiting example, the trifunctional polythiol compound may include compounds derived from C7H... 16 S5 represents the compound. In one embodiment, the trifunctional polythiol compound may include a compound represented by Formula 1.

[0037] [Formula 1]

[0038]

[0039] As described above, trifunctional polythiols can be used or included as the first polythiols compound. Compared with tetrafunctional polythiols, trifunctional polythiols have relatively higher economic efficiency and lower viscosity, thereby improving processability, etc.

[0040] The polythiol composition according to the exemplary embodiments may further include a second polythiol compound. For example, the second polythiol compound may be included or added as a reactivity modifier or reaction rate modifier of the polythiol composition.

[0041] In one embodiment, the second polythiol compound may include a polythiol compound with a molecular weight or carbon number greater than that of the first polythiol compound. In another embodiment, the second polythiol compound may have the same number of functional groups as the first polythiol compound. In this case, the first and second polythiol compounds may each comprise a trifunctional polythiol compound.

[0042] In some embodiments, the second polythiol compound may include C9H 20 S6 represents the compound. In some embodiments, the second polythiol compound may include a trifunctional thiol compound represented by formula 2.

[0043] [Equation 2]

[0044]

[0045] As described above, the second polythiol compound may be included in the composition together with the first polythiol compound to act as a regulator or buffer for the low glass transition temperature and high reaction rate of the first polythiol compound.

[0046] Therefore, the formation of streaks caused by the excessively high reaction rate and fluidity of trifunctional polythiol compounds can be suppressed. Furthermore, the total thiol value and liquid refractive index of the polythiol composition can be finely adjusted using a second polythiol compound.

[0047] Furthermore, mechanical properties of the lens, such as casting stability, can be improved by increasing the glass transition temperature of the polythiol composition.

[0048] Therefore, optical products such as lenses can be obtained by using polythiol compositions that have uniform optical properties and suppress coloration and streaking phenomena. Furthermore, the chemical stability of the polythiol composition or the optical product can be improved, thereby effectively suppressing clouding in the lens.

[0049] According to an exemplary embodiment, the ratio of the peak area (%) of the second polythiol compound to the peak area (%) of the first polythiol compound, measured by high performance liquid chromatography (HPLC) analysis chromatograms obtained at a wavelength of 230 nm, can be in the range of 0.05% to 5.0%.

[0050] For example, the proportion of polythiol compounds in a polythiol composition represented by Formula 1 can be in the range of 0.05% to 5.0%.

[0051] [Formula 1]

[0052] {(HPLC peak area of ​​the second polythiol compound) / (HPLC peak area of ​​the first polythiol compound)} × 100%

[0053] For example, if the proportion of the second polythiol compound is excessively increased, the reactivity between the polythiol composition and the isocyanate compounds may be excessively reduced. Therefore, during lens manufacturing, this could cause elution and clouding of the adhesive components included in the mold.

[0054] For example, when the proportion of the second polythiol compound is excessively reduced, the full effect of increasing the glass transition temperature and regulating reactivity through the second polythiol compound may not be achieved.

[0055] Therefore, when the peak area ratio defined by Equation 1 is maintained in the range of 0.05% to 5.0%, the reaction rate can be appropriately maintained, thereby effectively suppressing streaks / cloudiness in optical products and improving the durability of optical products.

[0056] Preferably, the proportion of the polythiol compound can be from 0.05% to 4.9% or from 0.08% to 4.85%. More preferably, the proportion of the polythiol compound can be from 0.5% to 4.9%, 1.0% to 4.9%, 1.0% to 3.0%, or 1.0% to 2.0%.

[0057] According to another aspect of the present invention, a method for preparing a polythiol composition comprising a plurality of polythiol compounds is provided. As described above, the polythiol composition may comprise at least two different trifunctional polythiol compounds, and may include a first polythiol compound and a second polythiol compound.

[0058] The preparation method of the polythiol composition according to the exemplary embodiments may include the following steps, processes or operations.

[0059] The preparation method of the polythiol composition according to the exemplary embodiments may include at least one of the steps, processes, or operations described in S10, S20, S30, and S40 below. It should be understood that, for ease of description, the terms "S10, S20, S30, and S40" are used to distinguish processes and are not intended to limit their order. For example, some or all of the processes in S10, S20, S30, and S40 below may be performed sequentially, and / or in a changed order depending on the process conditions.

[0060] S10) Reacts 2-mercaptoethanol with epihaloethanol to form a polyol intermediate.

[0061] S20) Additionally, 2-mercaptoethanol is added, and the polyol intermediate is reacted with thiourea under acidic conditions to prepare isothiourea onium salt.

[0062] S30) converts isothiourea onium salts into polythiool compounds.

[0063] For example, in step S10, a polyol intermediate is prepared by reacting 2-mercaptoethanol with an epihalool.

[0064] For example, the process of synthesizing polyol intermediates can be represented by the following scheme 1.

[0065] [Option 1]

[0066]

[0067] As shown in Scheme 1, 2-mercaptoethanol and epihaloethanol can react to prepare preliminary polyol intermediates, such as diol intermediates. The preliminary polyol intermediates can then be further reacted with 2-mercaptoethanol to prepare polyol intermediates, such as triol intermediates.

[0068] In some embodiments, a metal-containing catalyst, such as sodium hydroxide or potassium hydroxide, can be used in the reaction step of epihaloalcohol and 2-mercaptoethanol for the synthesis of trifunctional polythiol compounds.

[0069] As shown in Scheme 1 above, epichlorohydrin can be used as an epihaloalcohol. For example, the content of 2-mercaptoethanol based on 1 mol of epihaloalcohol can be 0.5 mol to 3 mol, preferably 0.7 mol to 2 mol, and more preferably 0.9 mol to 1.1 mol. The metal-containing catalyst can be used in an amount of 0.001 to 0.1 mol based on 1 mol of epihaloalcohol.

[0070] The preparation of preparative polyol intermediates and the preparation of polyol intermediates can be carried out under cooling conditions, and can be carried out, for example, at a reaction temperature of -5 to 40°C, preferably 0 to 30°C, more preferably 5 to 20°C.

[0071] For example, in step S20, 2-mercaptoethanol may be added, while the polyol intermediate reacts with thiourea under acidic conditions to prepare isothiourea onium salt.

[0072] In the preparation of isothiourea onium salts, a reflux process under acidic conditions can be used. To establish these acidic conditions, acidic compounds such as hydrochloric acid, hydrobromic acid, iodic acid, sulfuric acid, and phosphoric acid can be used. The reflux temperature can be from 90°C to 120°C, preferably from 100°C to 120°C, and the process can be carried out for about 1 hour to 10 hours.

[0073] In the preparation of isothiourea onium salts, 2-mercaptoethanol can be added to promote further reaction with polyol intermediates. Thus, for example, the synthesis of a second polythiol compound represented by Formula 2 and having a relatively high molecular weight or carbon number can be facilitated.

[0074] The amount of 2-mercaptoethanol added may be from 0.05 to 5.0% by weight (“wt.%”) based on the weight of thiourea. Within the above-mentioned range of addition, the aforementioned proportions of the polythiol compound represented by Formula 1 can be readily obtained. In one embodiment, the amount of 2-mercaptoethanol added is from 0.5 to 5 wt.% based on the weight of thiourea, preferably 1 to 5 wt.%, more preferably 1 to 3 wt.%, or 1 to 2 wt.%.

[0075] For example, in step S30, the prepared isothiourea onium salt can be converted into a polythiol compound.

[0076] According to an exemplary embodiment, isothiourea onion salts can be hydrolyzed under alkaline conditions to prepare polythiol compounds.

[0077] For example, an alkaline aqueous solution can be added to the reaction solution containing isothiourea onium salt to carry out hydrolysis. The alkaline aqueous solution may include alkali metal hydroxides and / or alkaline earth metal hydroxides, such as NaOH, KOH, LiOH, Ca(OH)2, etc.

[0078] In one embodiment, the reaction solution containing the isothiourea onium salt is cooled to a temperature of 20°C to 60°C, preferably 25°C to 55°C, and more preferably 25°C to 50°C. Subsequently, an alkaline aqueous solution may be added.

[0079] In one embodiment, an organic solvent may be added prior to the addition of an alkaline aqueous solution. The organic solvent may be of low or substantially non-reactive nature and have a boiling point above the thiolation reaction temperature to ensure stable thiolation.

[0080] Examples of organic solvents may include toluene, xylene, chlorobenzene, and dichlorobenzene. Preferably, toluene may be used, taking into account reaction stability and toxicity from organic solvents.

[0081] For example, steps S20 and S30 above can be represented together by the following scheme 2.

[0082] [Option 2]

[0083]

[0084] As described above, during the thiourea reaction / reflux process for preparing isothiourea onion salts, 2-mercaptoethanol can be added in an amount within a predetermined range. Therefore, as shown in Scheme 2, a polythiol composition comprising both a first polythiol compound (A) and a second polythiol compound (B) as the target polythiol compound can be obtained.

[0085] The polythiol compound or polythiol composition obtained as described above can be further purified. For example, by repeatedly performing acid washing and water washing processes, impurities included in the polythiol compound can be removed, and the transparency of the optical material prepared from the polythiol composition can be improved. Afterward, drying, filtration, etc., can be performed additionally.

[0086] 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.

[0087] 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.

[0088] After the pickling and washing processes, residual organic solvents and moisture can be removed by heating under reduced pressure, followed by filtration to obtain high-purity polythiol compounds.

[0089] In some embodiments, the residual moisture content of the polythiol compound or polythiol composition may be less than 1,000 ppm, preferably in the range of 100 ppm to 500 ppm, and more preferably in the range of 150 ppm to 400 ppm.

[0090] In some embodiments, the liquid refractive index of the polythiol composition at 25°C can be from 1.629 to 1.635, preferably from 1.629 to 1.631, and more preferably from 1.6295 to 1.6305.

[0091] In some embodiments, the thiol value (SHV) of the polythiol composition can be from about 88.0 g / eq to 90.0 g / eq. Preferably, the SHV is from 88.0 g / eq to 89.5 g / eq.

[0092] When titrating a polythiol composition sample with a 0.1N iodine standard solution, the SHV can be measured as a value obtained by dividing the sample weight by the iodine equivalent consumed.

[0093] According to the above-described embodiments, the preparation of the second polythiol compound can be controlled by introducing 2-mercaptoethanol in stages. However, the present invention is not limited to the above-described preparation method; the second polythiol compound can be introduced separately into the polythiol composition in an amount corresponding to the peak area within the above-described range. Furthermore, in addition to 2-mercaptoethanol, the amount of the second polythiol compound can be adjusted by other process conditions, such as reaction temperature and reaction time.

[0094] According to another aspect of the present invention, an optical composition (e.g., a polymeric composition for optical materials) comprising the above-described polythiol composition is provided.

[0095] Optical compositions may include polythiol compositions and isocyanate compounds. Optionally, polymerizable compositions for optical materials may include a first polythiol compound, a second polythiol compound, and an isocyanate compound.

[0096] Isocyanate compounds may include compounds that can be used as monomers in the synthesis of polythiourethanes. In a preferred embodiment, the 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.

[0097] The optical composition may further include additives such as mold release agents, reaction catalysts, heat stabilizers, ultraviolet absorbers, and bluing agents.

[0098] 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. These may be used alone or in combination of two or more thereof.

[0099] As reaction catalysts, catalysts used in the polymerization reaction of polyurethane 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.

[0100] 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 acid salts, phosphorus, lead, and organotin compounds. These can be used alone or in combination of two or more.

[0101] 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.

[0102] Examples of bluing agents can include dyes, fluorescent whitening agents, fluorescent pigments, and inorganic pigments, and can be appropriately selected according to 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.

[0103] Polysulfuric acid ester resins can be produced by the polymerization reaction of polysulfide compounds included in the polysulfide composition with isocyanate compounds, and the polymerization rate can be adjusted or controlled by the reactivity control operation of a second polysulfide compound included in the polysulfide composition.

[0104] Therefore, yellowing or cloudiness can be prevented, the formation of streaks can be suppressed, and optical products that maintain uniformity and improved optical properties over a long period of time can be obtained.

[0105] In some embodiments, the reaction rate of the optical composition included in Formula 1 below can be maintained in the range of 0.25 to 0.35, preferably in the range of 0.25 to 0.32, and more preferably in the range of 0.25 to 0.30, by means of the second polythiol compound.

[0106] In some embodiments, based on the total weight of the optical composition, it may include a polythiol composition or polythiol compound in an amount of about 40 to 60 wt.%, an isocyanate compound in an amount of about 40 to 60 wt.%, and additives in an amount of about 0.01 to 1 wt.%.

[0107] As described above, the second polythiol compound can be included in the polythiol composition, and therefore can be included in the optical composition together with the polythiol composition. In one embodiment, the second polythiol compound can be added to a composition comprising an isocyanate compound, thereby being included in the optical composition. In one embodiment, the second polythiol compound can be mixed with the first polythiol compound and the isocyanate compound, and thus included in the optical composition.

[0108] Furthermore, according to another aspect of the present invention, optical products manufactured using the above-described polymeric composition can be provided.

[0109] For example, after degassing the polymeric composition under reduced pressure, the resulting composition can be injected into a mold for shaping optical materials. Injection into the mold can be carried out at a temperature range of, for example, 20°C to 40°C, and preferably 20°C to 35°C.

[0110] After injection into the mold, the temperature can be gradually increased to allow the polymerization reaction of the polyurethane resin to proceed. The polymerization temperature can be from 20°C to 200°C, and preferably from 25°C to 125°C.

[0111] The polymerization temperature can be from 20°C to 150°C, and preferably from 25°C to 125°C. For example, the maximum polymerization temperature can be from 100°C to 150°C, preferably from 110°C to 140°C, and more preferably from 115°C to 130°C.

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

[0113] For example, by appropriately controlling the reaction rate within the aforementioned 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 to 10 hours, preferably 2 to 8 hours, and more preferably 3 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] After polymerization, the polymerized polyurethane resin can be separated from the mold to obtain optical products. Depending on the shape of the mold, the 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 the polythiol compound and isocyanate compound 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] As mentioned above, the glass transition temperature (Tg) and heat resistance of optical products can be improved by including a second polythiol compound in the polythiol composition.

[0118] In some embodiments, the glass transition temperature of the optical product can be above 85°C, preferably above 86°C, and can be, for example, from 85°C to 100°C. Preferably, the glass transition temperature of the optical product is from 86°C to 95°C, and more preferably from 86°C to 93°C, 87°C to 92°C, or 87°C to 90°C.

[0119] Optical products can be improved by further surface treatments such as antifouling, coloring, hard coating, surface polishing, and hardening.

[0120] In the following description, embodiments provided in this invention will be further described 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.

[0121] Example 1

[0122] 1) Synthesis of trifunctional polythiols

[0123] Add 200 parts by weight (“wt. parts”) of 2-mercaptoethanol (2-ME), 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.

[0124] Then, 360.5 wt. parts of thiourea and 3.6 wt. parts of 2-mercaptoethanol (based on 1 wt.% thiourea) were added, along with 666.8 wt. parts of hydrochloric acid with a purity of 36%, and the mixture was stirred for 3 hours under reflux at 110°C to carry out the thiourea onium chlorination reaction.

[0125] 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.

[0126] 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, followed by washing at 35°C to 45°C for 30 minutes. The washing was performed four times. After removing toluene and residual water under heating and reduced pressure, the solution was filtered under reduced pressure through a PTFE membrane filter to obtain 260 wt. parts of a polythiol composition comprising a trifunctional polythiol compound represented by Formula 1 as the main component.

[0127] 2) Preparation of polymeric compositions for optical materials and manufacture of lenses

[0128] 48.0 wt. parts of the polythiol composition prepared as described above were uniformly mixed with 52.0 wt. parts of xylene diisocyanate, 0.01 wt. parts of dibutyltin chloride, and 0.1 wt. parts of a phosphate release agent produced by ZELEC® UN tepan. Subsequently, a defoaming process was carried out at 600 Pa for 1 hour to prepare a polymeric composition for optical materials.

[0129] Then, the composition filtered through a 3 μm Teflon filter is injected into a mold provided with a glass mold and a tape. The temperature of the mold is slowly increased from 25°C to 120°C at a rate of 5°C / min, and polymerization is carried out at 120°C for 18 hours. After the polymerization is completed, the mold is disassembled, and then the product is further cured at 120°C for 4 hours to manufacture a lens sample.

[0130] Examples 2-5 and Comparative Examples

[0131] A polythiol composition and a lens sample were prepared in the same manner as in Example 1, except that the amount of 2-mercaptoethanol introduced during the reflux process under acidic conditions was changed as shown in Table 1 below.

[0132] Experimental Example

[0133] (1) Evaluation of thiol value (SHV)

[0134] About 0.1 g of the polythiol composition prepared in each example and comparative example is introduced into a beaker, 25 mL of chloroform is added, and then the mixture is stirred for 10 minutes. Then, 10 mL of methanol (MeOH) is added and stirred again for 10 minutes, then the resulting solution is titrated with a 0.1 N iodine standard solution, and then SHV (theoretical value: 86.8 g / eq) is measured according to the following formula 1.

[0135] [Formula 1] SHV (g / eq.) = Sample weight (g) / {0.1 × Iodine consumption (L)}

[0136] (2) Liquid refractive index

[0137] For the polythiol compositions synthesized in the examples and comparative examples, the refractive index at 25°C was measured using a liquid refractometer (RA-600 (KyotoElectronics)).

[0138] (3) HPLC analysis

[0139] In the polythiol compositions according to the examples and comparative examples, the peak area (%) of the polythiol compound represented by Formula 1 (Compound A) and the polythiol compound represented by Formula 2 (Compound B) included in the composition was measured by HPLC analysis performed under the following conditions, and the peak area ratio of the polythiol compounds was calculated.

[0140] <HPLC analysis conditions>

[0141] i) Instrument: LC 30A System (Shimadzu)

[0142] ii) Column: MC-Pack ODS-A 150mm × 6mm(S-5μm, 12nm)

[0143] iii) Mobile phase gradient: Acetonitrile (0.1% formic acid): Water (0.01M ammonium formate) = 40:60-100:0

[0144] vi) Wavelength: 230nm, Flow rate: 1.0ml / min, Injection volume: 10μl, Sample pretreatment: Sample: Solvent = 0.1g:10g

[0145] The retention time of compound A was measured in the range of 15 to 17 minutes, and the retention time of compound B was measured in the range of 17.5 to 19 minutes.

[0146] The specific compounds corresponding to the peaks of compound A and compound B in the HPLC chromatogram were identified using liquid chromatography-mass spectrometry (LC-MS) (Q Exactive: Thermo Fisher Scientific). Specifically, the molecular weight of compound B was measured to be 320.62 (actual molecular weight: 319.99), thus confirming the presence of compound B.

[0147] (4) Evaluation of stripes

[0148] 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.

[0149] ○: No stripes observed

[0150] △: Fine partial stripes were observed.

[0151] X: Stripes are clearly visible to the naked eye.

[0152] (5) Evaluation of lens opacity

[0153] For the lens samples of the embodiments and comparative examples prepared as described above, each sample was illuminated by a projector in a dark room, and the presence of haze or opaque material in the lens was visually confirmed.

[0154] (6) Measurement of polymerization rate (slope of reactivity)

[0155] 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. The measured values ​​were mathematically formulated (“mathematicalized”) 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.

[0156] [Mathematical Expression 1]

[0157] Y = a × exp(b × X)

[0158] In mathematical 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.

[0159] (7) Measurement of glass transition temperature (Tg)

[0160] The glass transition temperature (Tg) of the lens samples of the examples and comparative examples was measured using a thermomechanical analyzer (TMAQ400, TA Instruments) using the transmission method (load: 50g, tip diameter: Φ0.5mm, and heating rate: 10℃ / min).

[0161] The evaluation results are shown together in Tables 1 and 2 below.

[0162] [Table 1]

[0163]

[0164] [Table 2]

[0165]

[0166] Referring to Tables 1 and 2, in the cases where 2-Me is added during the reflow process and the compound of Formula 2 (compound B) is included in the above-described scope, it has been confirmed that the mechanical durability of the lens can be improved while increasing the glass transition temperature (e.g., greater than 86°C or 87°C).

[0167] In addition, although the reaction rate of the polythiol composition in the examples is maintained within an appropriate range, virtually no streaking or clouding of the lens occurs.

Claims

1. A polythiol composition comprising: The first polythiol compound represented by Formula 1 below; and The second polythiol compound represented by formula 2 below, The ratio of the peak area of ​​the second polythiol compound to the peak area of ​​the first polythiol compound, measured by HPLC analysis at 230 nm using an MC-Pack ODS-A column (150 mm × 6 mm, S-5 μm, 12 nm), a mobile phase gradient of acetonitrile containing 0.1% formic acid and water containing 0.01 M ammonium formate at a ratio of 40:60 to 100:0, a flow rate of 1.0 mL / min, and an injection volume of 10 μl, was 0.05% to 5.0%. [Formula 1] ， [Equation 2] 。 2. An optical composition comprising: Isocyanate compounds; and A polythiol composition, wherein the polythiol composition comprises: The first polythiol compound represented by Formula 1 below; and The second polythiol compound represented by formula 2 below, The ratio of the peak area of ​​the second polythiol compound to the peak area of ​​the first polythiol compound, as measured by HPLC analysis at 230 nm using an MC-Pack ODS-A column (150 mm × 6 mm, S-5 μm, 12 nm), a mobile phase gradient of acetonitrile containing 0.1% formic acid and water containing 0.01 M ammonium formate at a mobile phase ratio of 40:60 to 100:0, a flow rate of 1.0 mL / min, and an injection volume of 10 μl, is 0.05% to 5.0%. [Formula 1] ， [Equation 2] 。 3. An optical product comprising: copolymers of polythiol compositions and isocyanate compounds, The polythiol composition comprises: The first polythiol compound represented by formula 1 below; and The second polythiol compound represented by formula 2 below, The ratio of the peak area of ​​the second polythiol compound to the peak area of ​​the first polythiol compound, as measured by HPLC analysis at 230 nm using an MC-Pack ODS-A column (150 mm × 6 mm, S-5 μm, 12 nm), a mobile phase gradient of acetonitrile containing 0.1% formic acid and water containing 0.01 M ammonium formate at a mobile phase ratio of 40:60 to 100:0, a flow rate of 1.0 mL / min, and an injection volume of 10 μl, is 0.05% to 5.0%. [Formula 1] ， [Equation 2] 。 4. The optical product according to claim 3, wherein the glass transition temperature of the optical product is greater than 86°C.

5. The optical product according to claim 3, wherein the glass transition temperature of the optical product is in the range of 87°C to 92°C.

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