Polythiol compositions, optically polymerizable compositions, and optical products

Abstract

The polythiol composition according to the exemplary embodiment includes a first polythiol compound and a second polythiol compound having a molecular weight higher than that of the first polythiol compound and a number of functional groups greater than or equal to that of the first polythiol compound. The content of the second polythiol compound is 500 ppm to 20,000 ppm based on the weight of the first polythiol compound. The reaction rate of the isocyanate-based compound can be controlled by the second polythiol compound, thereby preventing the streak phenomenon of the optical product and the mechanical properties of the optical product can be improved.

Description

Technical Field

[0001] This invention relates to polythiol compositions, optically polymerizable compositions (“polymerizable compositions for optical materials”), and optical products. More specifically, this invention relates to polythiol compositions comprising a variety of thiol compounds, polymerizable compositions for optical materials comprising said polythiol compositions, and optical products manufactured using said polymerizable 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 isothiourea onium salts, followed by hydrolysis with ammonia.

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

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

[0007] Another objective according to the exemplary embodiments is to provide a polymeric composition for optical materials comprising a polythiol composition having improved reactivity and optical properties.

[0008] Furthermore, another objective according to the exemplary embodiments is to provide an optical product made of an optical material using a polymeric composition.

[0009] The polythiol composition according to an exemplary embodiment includes: a first polythiol compound; and a second polythiol compound with a molecular weight higher than that of the first polythiol compound and a number of functional groups greater than or equal to that of the first polythiol compound. The content of the second polythiol compound is from 500 to 20,000 ppm based on the weight of the first polythiol compound.

[0010] In some embodiments, the first polythiol compound may include a trifunctional polythiol compound, and the second polythiol compound may include a tetrafunctional polythiol compound.

[0011] In some embodiments, the first 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:

[0012] [Formula 1]

[0013]

[0014] [Equation 2-1]

[0015]

[0016] [Equation 2-2]

[0017]

[0018] [Equation 2-3]

[0019] .

[0020] In some embodiments, the second polythiol compound may include C 12 H 26 S8 represents the compound.

[0021] In some embodiments, the second polythiol compound may include at least one of the compounds represented by formula 3-1 and formula 3-2:

[0022] [Equation 3-1]

[0023]

[0024] [Equation 3-2]

[0025] .

[0026] In some embodiments, the second polythiol compound may include the compound represented by Formula 3-1 and the compound represented by Formula 3-2 in amounts of 500 to 10,000 ppm, respectively.

[0027] In some embodiments, the content of the second polythiol compound can be from 1,000 to 20,000 ppm.

[0028] A polymeric composition for optical materials according to an exemplary embodiment includes: a first polythiol compound; a second polythiol compound with a molecular weight higher than that of the first polythiol compound and a number of functional groups greater than or equal to that of the first polythiol compound; and an isocyanate compound. The content of the second polythiol compound is from 500 to 20,000 ppm based on the weight of the first polythiol compound.

[0029] In some embodiments, the second polythiol compound may include C 12 H 26 S8 represents the compound.

[0030] In some embodiments, the second polythiol compound may include at least one of the compounds represented by formula 3-1 and formula 3-2:

[0031] [Equation 3-1]

[0032]

[0033] [Equation 3-2]

[0034] .

[0035] In some implementations, the first polythiol compound may include a trifunctional polythiol compound.

[0036] In some embodiments, the first polythiol compound may include a compound represented by Formula 1:

[0037] [Formula 1]

[0038] .

[0039] According to an exemplary embodiment, an optical product is provided comprising a polythiourethane resin wherein a polythiol compound and an isocyanate compound are polymerized. The polythiol compound comprises a first polythiol compound and a second polythiol compound having a molecular weight higher than that of the first polythiol compound and having a number of functional groups greater than or equal to that of the first polythiol compound. The content of the second polythiol compound is from 500 to 20,000 ppm based on the weight of the first polythiol compound.

[0040] In some embodiments, the second polythiol compound may include C 12 H 26 S8 represents the compound.

[0041] In some implementations, the refractive index of the optical product is between 1.56 and 1.78.

[0042] According to the above embodiments, the polythiol composition may include a first polythiol compound and a second polythiol compound. The molecular weight of the second polythiol compound may be greater than that of the first polythiol compound, and the number of functional groups in the second polythiol compound may be greater than or equal to the number of functional groups in the first polythiol compound.

[0043] Because adding a small amount of the second polythiol compound can reduce the reaction rate of the first polythiol compound, it prevents streaking caused by excessive flow during lens manufacturing. Furthermore, the overall glass transition temperature of the polythiol composition is increased by the second polythiol compound, which also improves the mechanical properties of the lens.

[0044] In some embodiments, the first polythiol compound may include a trifunctional polythiol compound, and the second polythiol compound may include a tetrafunctional polythiol compound. Therefore, the reactivity of the trifunctional polythiol compound can be appropriately controlled to obtain a highly reliable lens with complementary mechanical and optical properties. Detailed Implementation

[0045] 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.

[0046] 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.

[0047] According to one aspect of this application, 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.

[0048] The first polythiol compound may include the polythiol compound used as a base material in the polythiol composition or polymeric composition for optical materials described below. The first polythiol compound may be included as the main polythiol compound in the polythiol composition.

[0049] The first polythiol compound may include trifunctional polythiol compounds and / or tetrafunctional polythiol compounds.

[0050] Non-limiting examples of trifunctional polythiol compounds may include those composed of C7H 16 S5 represents the compound. In one embodiment, the trifunctional polythiol compound may include a compound represented by Formula 1.

[0051] [Formula 1]

[0052]

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

[0054] After reacting a polyol compound with a thiourea compound under acidic conditions to generate a thiourea onion salt, a trifunctional polythiol compound can be prepared by hydrolysis under alkaline conditions.

[0055] The synthesis of trifunctional polythiol compounds can be illustrated by the following scheme 1.

[0056] [Option 1]

[0057]

[0058] 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.

[0059] Tetrafunctional polythiols can include, for example, compounds derived from C 10 H 22 Compounds represented by S7. Non-limiting examples of tetrafunctional polythiols may include compounds represented by formulas 2-1 to 2-3 below.

[0060] [Equation 2-1]

[0061]

[0062] [Equation 2-2]

[0063]

[0064] [Equation 2-3]

[0065]

[0066] Tetrafunctional polythiols can be synthesized from polyols, for example, obtained by reacting 2-mercaptoethanol with epihaloethanol.

[0067] Polyol compounds can react with metal sulfides to generate tetrafunctional polyol intermediates. These intermediates then react with thiourea under acidic conditions to form thiourea onium salts, which can be hydrolyzed under alkaline conditions to prepare tetrafunctional polythiool compounds.

[0068] The above-described synthetic method for tetrafunctional polythiols can be illustrated by the following scheme 2.

[0069] [Option 2]

[0070]

[0071] 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.

[0072] As illustrated in Schemes 1 and 2 above, epichlorohydrin can be used as an epihaloalcohol. For example, the content of 2-mercaptoethanol based on 1 mole of epihaloalcohol can be 0.5 to 3 moles, preferably 0.7 to 2 moles, more preferably 0.9 to 1.1 moles. The amount of basic catalyst based on 1 mole of epihaloalcohol can be 0.001 to 0.1 mol, preferably 0.01 to 0.1 mol.

[0073] In schemes 1 and 2, reflux under acidic conditions can be used to generate isothiourea onium salts via reaction with thiourea. To create such 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 90 to 120°C, preferably 100 to 120°C, and the reflux can be carried out for about 1 to 10 hours, preferably 2 to 6 hours.

[0074] As described above, after the formation of isothiourea onium salt, trifunctional or tetrafunctional polythiol compounds are prepared by hydrolysis under alkaline conditions. For example, it can be hydrolyzed by adding an alkaline aqueous solution to the reaction solution containing the isothiourea onium salt.

[0075] In one embodiment, the reaction solution containing isothiourea onium salt is cooled to a temperature of 20 to 60°C, preferably 25 to 55°C, more preferably 25 to 50°C. An alkaline aqueous solution may then be added.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] In a preferred embodiment, a trifunctional polythiol compound can be used as the first polythiol compound. Trifunctional polythiol compounds are advantageous in terms of economic benefits and ease of processing due to their low viscosity.

[0084] The polythiol composition according to the exemplary embodiments may further include a second polythiol compound. The second polythiol compound may be included or added as a modifier of the reactivity or reaction rate of the polythiol composition.

[0085] In one embodiment, the second polythiol compound may include a polythiol compound with a molecular weight greater than that of the first polythiol compound. In another embodiment, the second polythiol compound may include a polythiol compound with a number of functional groups greater than or equal to the number of functional groups (thiol groups) of the first polythiol compound.

[0086] In some embodiments, the second polythiol compound may include C 12 H 26 S8 represents the compound. In some embodiments, the second polythiol compound may include a tetrafunctional thiol compound represented by formula 3-1 and / or formula 3-2.

[0087] [Equation 3-1]

[0088]

[0089] [Equation 3-2]

[0090]

[0091] In one embodiment, the compound of formula 3-1 or the compound of formula 3-2 may be used alone as a second polythiol compound. In another embodiment, the compound of formula 3-1 or the compound of formula 3-2 may be used in combination as a second polythiol compound.

[0092] The second polythiol compound may have a larger molecular weight or more carbon atoms than the first polythiol compound. Therefore, the second polythiol compound can be used to suppress the excessive increase in the reaction rate of the polythiol composition or the first polythiol compound with the isocyanate compounds described below.

[0093] As mentioned above, using trifunctional polythiols as the first polythiols compound is advantageous in terms of economic benefits and ease of processing. However, the rapid reaction rate of trifunctional polythiols can lead to streaks in lenses. Furthermore, the relatively high fluidity and low glass transition temperature (Tg) of trifunctional polythiols may also reduce the mechanical properties of optical products such as lenses.

[0094] However, according to an exemplary embodiment, when a second polythiol compound having a relatively large molecular weight, number of functional groups, and number of carbon atoms is mixed together as a reaction modifier, an excessive increase in the reaction rate of the trifunctional polythiol compound can be suppressed, and the overall glass transition temperature of optical products such as lenses made from the polythiol composition can be increased.

[0095] For example, when a second polythiol compound, which is a tetrafunctional compound with a large chain length, is added, the intermolecular bonds and interactions of the first polythiol compound can be buffered or controlled, and the excessive increase in reactivity of the trifunctional polythiol compound can be mitigated, for example.

[0096] Furthermore, the addition of a high molecular weight second polythiol compound can increase the glass transition temperature (Tg) of optical products by increasing intermolecular attraction and interaction, and can also enhance heat resistance.

[0097] Therefore, it is possible to obtain an optical product in which all economic advantages, ease of processing, optical properties, and mechanical properties are improved in a good balance.

[0098] In some embodiments, the aforementioned tetrafunctional polythiol compound can be used as the first polythiol compound. In this case, the above-mentioned effects can be obtained substantially similarly when a second polythiol compound having a relatively higher molecular weight, number of functional groups, and number of carbon atoms compared to the tetrafunctional polythiol compound is mixed together.

[0099] According to an exemplary embodiment, a second polythiol compound may be included in the range of about 500 to 20,000 ppm by weight of the first polythiol compound. Within the above range, the second polythiol compound can prevent excessive reduction of the reaction rate and coloration / cloudiness of the lens, while sufficiently achieving the effects of suppressing the reaction rate and increasing the glass transition temperature.

[0100] Preferably, the content of the second polythiol compound can be from 1,000 to 20,000 ppm. More preferably, the content of the second polythiol compound can be from 10,000 to 20,000 ppm.

[0101] In a preferred embodiment, the second polythiol compound may simultaneously comprise the compound of formula 3-1 and the compound of formula 3-2. In this case, the content of the compound of formula 3-1 and the compound of formula 3-2 may be about 500 to 10,000 ppm, more preferably about 5,000 to 10,000 ppm.

[0102] For example, when compounds of formula 3-2 with relatively high molecular weight and carbon number are used simultaneously with compounds of formula 3-1, an appropriate reaction rate can be maintained while preventing excessive increase in the reaction rate and turbidity.

[0103] In addition, according to another aspect of this application, a polymeric composition for optical materials comprising the above-described polythiol composition is provided.

[0104] Polymerizable compositions for optical materials may include polythiol compositions and isocyanate compounds. Optionally, polymerizable compositions for optical materials may include the first polythiol compound, the second polythiol compound, and the isocyanate compound described above.

[0105] 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.

[0106] Polymer compositions for optical materials may further include additives such as release agents, reaction catalysts, heat stabilizers, ultraviolet absorbers, and bluing agents.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] Bluing agents may be included as color modifiers 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.

[0111] 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.

[0112] Polysulfuric acid ester resins can be produced by the polymerization reaction of polysulfide compounds contained in the polysulfide composition with isocyanate compounds, and the polymerization rate can be adjusted or controlled by the reaction control effect of a second polysulfide compound contained in the polysulfide composition.

[0113] Therefore, it can prevent yellowing or cloudiness, suppress the formation of streaks, and manufacture optical products that maintain uniform and improved optical properties over a long period of time.

[0114] 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% to 60% by weight (“wt.%”), and an isocyanate compound may be included in an amount of about 40% to 60% by weight, while an additive may be included in an amount of about 0.01% to 1% by weight. As described above, a second polythiol compound may be included in an amount ranging from about 500 to 20,000 ppm based on the weight of the first polythiol compound.

[0115] In some embodiments, the reaction rate of the polymeric composition of the optical material included in Formula 1, which will be described below, can be appropriately controlled by a second polythiol compound.

[0116] In one embodiment, when a trifunctional polythiol compound is used as the first polythiol compound, the reaction rate can be from 0.20 to 0.35, preferably from 0.24 to 0.35, and more preferably from 0.24 to 0.30. In one embodiment, when a tetrafunctional polythiol compound is used as the first polythiol compound, the reaction rate can be less than 0.20.

[0117] As described above, the second polythiol compound may be included in a polythiol composition, which will be included together in a polymerizable composition for optical materials. In one embodiment, the second polythiol compound may be added to a composition comprising an isocyanate compound, which will be included in a polymerizable composition for optical materials. In one embodiment, the second polythiol compound may be mixed with both a polythiol compound and an isocyanate compound to be included in a polymerizable composition for optical materials.

[0118] Furthermore, according to another aspect of this application, an optical product manufactured using the aforementioned optical material and a polymeric composition can be provided.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] For example, by appropriately controlling the reaction rate within the above temperature range, lenses with uniform optical and mechanical properties can be easily obtained.

[0123] 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.

[0124] Depending on the shape of the mold, optical products can be manufactured in the form of eyeglass lenses, camera lenses, light-emitting diodes, etc.

[0125] 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.

[0126] As described 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. In some embodiments, the glass transition temperature of the optical product can be from 90°C to 110°C. Preferably, the glass transition temperature of the optical product can be from 92°C to 106°C, and more preferably from 93°C to 106°C, 94°C to 106°C, or 95°C to 106°C.

[0127] Optical products can be improved by further surface treatments such as antifouling, coloring, hard coating, surface polishing, and hardening.

[0128] 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.

[0129] Preparation Example

[0130] 1) Preparation Example 1: Synthesis of trifunctional polythiol compounds

[0131] 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.

[0132] 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 onium chlorination reaction.

[0133] 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.

[0134] 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 four washes were performed at 35°C to 45°C, each 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.

[0135] 2) Preparation Example 2: Synthesis of Tetrafunctional Polythiol Compounds

[0136] 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.

[0137] 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 onium chlorination reaction.

[0138] 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.

[0139] 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 four washes were performed at 35°C to 45°C, each 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.

[0140] Examples and Comparative Examples

[0141] Compared with the trifunctional or tetrafunctional polythiol compounds (first polythiol compounds) prepared as described above, the polythiol compositions of the Examples and Comparative Examples were prepared by adding the compound of Formula 3-1 (compound (A)) and / or the compound of Formula 3-2 (compound (B)) as second polythiol compounds in the amounts described in Table 1.

[0142] [Formula 3-1] Compound (A)

[0143]

[0144] [Formula 3-2] Compound (B)

[0145]

[0146] Preparation of polymeric compositions for optical materials and manufacture of lenses

[0147] 1) The polythiol compositions of the examples and comparative examples were received to prepare the trifunctional polythiol of Example 1, comprising 48.0 wt. parts. The received composition was then uniformly mixed with 52.0 wt. parts xylene diisocyanate, 0.012 wt. parts dibutyltin chloride, and 0.1 wt. parts 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.

[0148] 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.

[0149] 2) The polythiol compositions of the examples and comparative examples were received to prepare the tetrafunctional polythiol of Example 2, comprising 49.0 wt. parts. The received composition was then uniformly mixed with 51.0 wt. parts xylene diisocyanate, 0.01 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.

[0150] 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.

[0151] Experimental Example

[0152] (1) Evaluation of stripes

[0153] 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.

[0154] ○: No stripes observed

[0155] △: Fine partial stripes were observed.

[0156] x: Stripes are clearly visible to the naked eye.

[0157] (2) Evaluation of lens opacity

[0158] 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.

[0159] The evaluation criteria are as follows.

[0160] ○: No fog

[0161] △: Partial fog was observed.

[0162] x: The overall haze was clearly observed.

[0163] (3) Measurement of polymerization rate (reactivity slope)

[0164] 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.

[0165] [Formula 1]

[0166] y = a × exp(b × X)

[0167] In Equation 1, the value of 'a' represents the initial viscosity (cps), and the value of 'b' represents the reaction rate. The measured values ​​are rounded to two decimal places.

[0168] (4) Measurement of glass transition temperature (Tg)

[0169] 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).

[0170] The evaluation results are shown in Table 1 below.

[0171] [Table 1]

[0172]

[0173] Referring to Table 1, a lens is manufactured by using a polythiol composition or polymeric composition comprising the second polythiol compound in the specific content range described above, which reduces cloudiness and improves mechanical properties due to increased glass transition temperature, while preventing streaking.

[0174] On the other hand, compared with Examples 11 to 13, which used a tetrafunctional polythiol compound as the first polythiol compound, it can be confirmed that in Examples 1 to 10, which used a trifunctional compound, streaks and turbidity were significantly improved compared with the comparative examples using other trifunctional polythiol compounds.

Claims

1. A polythiol composition comprising: First polythiol compound; and A second polythiol compound with a molecular weight higher than that of the first polythiol compound. The first polythiol compound is a trifunctional polythiol compound, and the second polythiol compound is a tetrafunctional polythiol compound. The content of the second polythiol compound is based on a weight of 500 ppm to 20,000 ppm of the first polythiol compound. The first polythiol compound includes a trifunctional polythiol compound represented by Formula 1: [Formula 1] ,and The second polythiol compound includes at least one of the compounds represented by Formula 3-1 and the compounds represented by Formula 3-2: [Equation 3-1] [Equation 3-2] 。 2. The polythiol composition according to claim 1, wherein the second polythiol compound comprises, respectively, the compound represented by formula 3-1 and the compound represented by formula 3-2 in an amount of 500 ppm to 10,000 ppm.

3. The polythiol composition according to claim 1, wherein the content of the second polythiol compound is from 1,000 ppm to 20,000 ppm.

4. A polymeric composition for optical materials, comprising: First polythiol compound; A second polythiol compound with a molecular weight higher than that of the first polythiol compound; and Isocyanate compounds, The first polythiol compound is a trifunctional polythiol compound, and the second polythiol compound is a tetrafunctional polythiol compound. The content of the second polythiol compound is based on a weight of 500 ppm to 20,000 ppm of the first polythiol compound. The first polythiol compound includes compounds represented by Formula 1: [Formula 1] ,and The second polythiol compound includes at least one of the compounds represented by Formula 3-1 and the compounds represented by Formula 3-2: [Equation 3-1] [Equation 3-2] 。 5. An optical product comprising: Polysulfuric acid ester resins, which are polymerized with polythiol compounds and isocyanate compounds, are among the polymers. The polythiol compound includes a first polythiol compound and a second polythiol compound with a molecular weight higher than that of the first polythiol compound. The first polythiol compound is a trifunctional polythiol compound, and the second polythiol compound is a tetrafunctional polythiol compound. The content of the second polythiol compound is based on a weight of 500 ppm to 20,000 ppm of the first polythiol compound. The first polythiol compound includes a trifunctional polythiol compound represented by Formula 1: [Formula 1] ,and The second polythiol compound includes at least one of the compounds represented by Formula 3-1 and the compounds represented by Formula 3-2: [Equation 3-1] [Equation 3-2] 。 6. The optical product according to claim 5, wherein the refractive index of the optical product is from 1.56 to 1.78.

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