KR102707088B1 - Polythiol composition, optical composition and optical product - Google Patents

Abstract

According to exemplary embodiments, a polythiol composition includes a main polythiol compound and a sub-compound having a molecular weight larger than that of the main polythiol compound. A peak area (%) of a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm corresponding to the sub-compound in a retention time range of 34 minutes to 40 minutes is 2.5% or less. An optical product having excellent transmittance and optical properties can be manufactured by finely controlling the sub-compound.

Description

POLYTHIOL COMPOSITION, OPTICAL COMPOSITION AND OPTICAL PRODUCT

The present invention relates to a polythiol composition, an optical composition and an optical product. More specifically, the present invention relates to a polythiol composition comprising a polythiol-based compound and an additional compound, an optical composition comprising the same and an optical product formed therefrom.

Polythiol compounds are widely used, for example, as raw materials for manufacturing polyurethane resins. For example, polythiol compounds are used for manufacturing optical lenses using polyurethane resins, and the quality, such as purity, of the polythiol compound as a raw material for manufacturing can directly affect the quality of the optical lens.

For example, a polythiourethane compound manufactured by reacting a polythiol compound and an isocyanate compound can be utilized as a base material for the optical lens.

For example, Korean Patent Publication No. 10-1338568 discloses a method for synthesizing a polythiol compound by reacting a polyol compound with thiourea to produce an isothiouronium salt, which is then hydrolyzed using aqueous ammonia.

The optical properties of optical products such as lenses may vary depending on the polymerization reaction rate or reactivity of the synthesized polythiol compound and the isocyanate compound. For example, the reaction rate may vary due to compounds other than the desired target polythiol compound, and thus the reliability of the desired optical properties of the lens may be reduced.

Korean Patent Publication No. 10-1338568

One object, according to exemplary embodiments, is to provide a polythiol composition having improved reactive properties and optical properties and a method for producing the same.

One object, according to exemplary embodiments, is to provide an optical composition comprising a polythiol composition having improved reactive characteristics and optical properties.

One object of the present invention is to provide an optical product manufactured using the optical composition.

According to exemplary embodiments, a polythiol composition includes a main polythiol compound and a sub-compound having a molecular weight greater than that of the main polythiol compound. A peak area (%) of a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm corresponding to the sub-compound in a retention time range of 34 minutes to 40 minutes exceeds 0% and is 2.5% or less.

In some embodiments, the peak area of the HPLC analysis graph in the retention time range of 34 minutes to 40 minutes may be 1.5 to 2.5%.

In some embodiments, multiple peaks are detected in the retention time range of 34 minutes to 40 minutes of the HPLC analysis graph, and the sum of the areas of the multiple peaks may exceed 0% and be 2.5% or less.

In some embodiments, the main polythiol compound may include a tetrafunctional polythiol compound having a retention time in the range of 24 minutes to 28 minutes in the HPLC analysis graph.

In some embodiments, the tetrafunctional polythiol compound may include a compound represented by C ₁₀ H ₂₂ S ₇ .

In some embodiments, the tetrafunctional polythiol compound may include at least one of the compounds represented by the following chemical formulae 1-1 to 1-3.

[Chemical Formula 1-1]

[Chemical Formula 1-2]

[Chemical Formula 1-3]

In some embodiments, the peak area (%) in the retention time range of 24 minutes to 28 minutes of the HPLC analysis graph may be 80% to 90%.

In some embodiments, the peak area (%) in the retention time range of 24 minutes to 28 minutes of the HPLC analysis graph may be 81% to 85%.

In some embodiments, the peak area ratio defined by the following formula 1 of the polythiol composition may be from 1.5% to 3.1%.

[Formula 1]

Peak Area Ratio (%) = (A/B)*100

(In Equation 1, A is the peak area (%) included in the retention time range of 34 to 40 minutes in the HPLC analysis graph, and B is the peak area (%) included in the retention time range of 24 to 28 minutes in the HPLC analysis graph).

An optical composition according to exemplary embodiments includes a main polythiol compound and a sub-compound having a molecular weight greater than that of the main polythiol compound, and a polythiol composition having a peak area (%) in a retention time range of 34 minutes to 40 minutes in a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm corresponding to the sub-compound exceeding 0% and 2.5% or less, and an isocyanate-based compound.

According to exemplary embodiments, an optical product comprising a polythiol composition and a polymer of an isocyanate-based compound is provided. The polythiol composition comprises a main polythiol compound and a sub-compound having a molecular weight greater than that of the main polythiol compound, and a peak area (%) of a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm corresponding to the sub-compound in a retention time range of 34 minutes to 40 minutes is 2.5% or less.

A polythiol composition according to exemplary embodiments may include a main polythiol compound, such as a tetrafunctional polythiol compound, and a sub-compound having a molecular weight greater than that of the main polythiol compound. By finely adjusting the content range of the sub-compound measured by HPLC, the reactivity of the polythiol composition can be appropriately controlled.

Accordingly, by controlling the reaction rate of the polythiol composition with the isocyanate compound, the phenomenon of streaking and clouding can be suppressed, and a high-transmittance optical lens having a desired refractive index can be obtained with high reliability.

Figures 1 to 3 are images of high-performance liquid chromatography (HPLC) analysis graphs of polythiol compositions manufactured according to examples and comparative examples.

Hereinafter, the embodiments of the present application will be described in detail. However, the present invention can be modified in various ways and can have various forms, so specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and it should be understood that it includes all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms defined in commonly used dictionaries, such as those defined in common dictionaries, should be interpreted as having a meaning consistent with the meaning they have in the context of the relevant art, and shall not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

According to one aspect of the present application, a polythiol composition comprising polythiol compounds is provided.

According to exemplary embodiments, the polythiol composition may include a main polythiol compound and a sub-compound.

The main polythiol compound may refer to a polythiol compound that is included in the polythiol composition and is a target material in which a polymerization reaction is induced with an isocyanate compound. For example, the main polythiol compound may be a compound included in the largest amount in the polythiol composition. According to exemplary embodiments, the main polythiol compound may be a compound corresponding to a main peak or a maximum peak measured through a high-performance liquid chromatography (HPLC) analysis graph.

The above main polythiol compound may include a trifunctional polythiol compound and/or a tetrafunctional polythiol compound.

As a non-limiting example, the tetrafunctional polythiol compound may include a compound represented by, for example, C ₁₀ H ₂₂ S ₇ . Non-limiting examples of the tetrafunctional polythiol compound include compounds represented by the following chemical formulas 1-1 to 1-3.

[Chemical Formula 1-1]

[Chemical Formula 1-2]

[Chemical Formula 1-3]

The trifunctional polythiol compound may include a compound represented by C ₇ H ₁₆ S ₅ . In one embodiment, the trifunctional polythiol compound may include a compound represented by the following chemical formula 2.

[Chemical formula 2]

In a preferred embodiment, the main polythiol compound may include the tetrafunctional polythiol compound. In this case, it may be advantageous in terms of uniformity of optical properties such as refractive index of an optical product such as a lens, and mechanical stability such as durability.

The sub-compound may be a compound having a higher molecular weight than the main polythiol compound. For example, the sub-compound may include a reaction initiator for synthesizing a polythiol compound (e.g., 2-mercaptoethanol and epihalohydrin), an intermediate such as a polyol compound, an aggregate or oligomer of a polythiol compound, etc.

According to exemplary embodiments, the sub-compound may be a compound corresponding to a peak within a retention time range of 34 to 40 minutes in a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm for the polythiol composition.

According to exemplary embodiments, the peak area (%) included in the retention time range of 34 minutes to 40 minutes in the HPLC analysis graph corresponding to the sub-compound may be 2.5% or less. For example, the peak area (%) included in the retention time range of 34 minutes to 40 minutes in the HPLC analysis graph may be greater than 0% and less than or equal to 2.5%.

In one embodiment, the peak area (%) corresponding to the sub-compound may range from 0.5% to 2.5%, preferably from 1% to 2.5%, more preferably from 1.5% to 2.5% or from 1.5% to 2.2%.

In some embodiments, the retention time range of 34 minutes to 40 minutes of the HPLC analysis graph for the polythiol composition may include multiple peaks. In this case, the sub-compound includes multiple types of compounds, and the sum of the multiple peak areas within the retention time range may be included within the numerical range described above.

If the peak area (%) of the above sub-compound increases excessively, the reaction rate or reactivity of the polythiol composition with the isocyanate compound may excessively decrease, and the purity of the polythiol composition may deteriorate. Accordingly, a whitening phenomenon may occur in an optical product such as a lens manufactured using the polythiol composition.

When the above-mentioned sub-compound is included in an appropriate amount within the above-mentioned numerical range, excessive flowability and increase in reaction speed of the composition can be suppressed. Accordingly, the striae phenomenon of an optical product manufactured using the above-mentioned polythiol composition can also be prevented.

As described above, in the HPLC analysis graph of the polythiol composition, the main polythiol compound may correspond to the maximum peak. In some embodiments, the main polythiol compound may be included within a retention time range of about 24 minutes to 28 minutes in the HPLC analysis graph.

In some embodiments, the peak area (%) included in the retention time range of 24 minutes to 28 minutes in the HPLC analysis graph may be 80% to 90%. In one embodiment, the peak area (%) included in the retention time range of 24 minutes to 28 minutes in the HPLC analysis graph may be 81% to 90%, more preferably 81% to 85%, or 82% to 85%.

Within the above range, the purity and desired optical properties of the optical composition or optical product can be secured, and striae caused by excessive increase in reaction speed can be prevented.

In some embodiments, the retention time range of 24 minutes to 28 minutes of the HPLC analysis graph for the polythiol composition may include multiple peaks. In this case, the sum of the multiple peak areas within the retention time range may be included within the numerical range described above.

In exemplary embodiments, the peak area ratio defined by the following formula 1 of the polythiol composition may be 1.5% to 3.1%.

[Formula 1]

Peak Area Ratio (%) = (A/B)*100

In Equation 1, A is the peak area (%) included in the retention time range of 34 to 40 minutes in the HPLC analysis graph, and B is the peak area (%) included in the retention time range of 24 to 28 minutes in the HPLC analysis graph.

In one embodiment, the peak area ratio may be from 1.8% to 3.1%, and preferably from 2.0% to 3.1% or from 2.0% to 3.0%.

Within the above peak area ratio, sufficient heat resistance and an appropriate reaction speed range can be efficiently implemented without deteriorating the desired refractive index, transparency and purity obtained from the optical product.

The sub-compound has a molecular weight greater than that of the main polythiol compound, and thus may have a longer retention time than that of the main polythiol compound. The sub-compound may be included in the polythiol composition, for example, as a macromolecule, and may function as a reaction rate controller of the polythiol composition.

In addition, the addition of a sub-compound having a large molecular weight can increase the glass transition temperature (Tg) of the optical product through increased intermolecular force and interaction, and can also enhance heat resistance.

According to one aspect of the present application, a method for producing the polythiol composition described above is provided. As described above, the polythiol composition may include a main polythiol compound and a sub-compound.

A method for preparing a polythiol composition according to exemplary embodiments may comprise the following steps, processes or actions.

A method for producing a polythiol composition according to exemplary embodiments may include at least one of the steps, processes, or actions described as S10, S20, S30, and S40 below. It should be understood that the terms "S10, S20, S30, and S40" below are used to distinguish the processes for convenience of description and are not intended to limit the order. For example, some or all of the processes of S10, S20, S30, and S40 below may be performed sequentially, and may be performed with changes depending on the process conditions.

S10) Formation of preliminary polyol compound by reacting 2-mercaptoethanol and epihalohydrin at a first temperature

S20) Metal sulfide is added to the above preliminary polyol compound and the temperature is increased to a second temperature higher than the first temperature to produce a polyol intermediate.

S30) The polyol intermediate is reacted with thiourea under acid conditions to produce an isothiouronium salt.

S40) Conversion of the above isothiouronium salt into a polythiol compound

For example, in the above step S10, 2-mercaptoethanol and epihalohydrin can be used as reaction initiating materials, and the reaction can proceed according to the following reaction scheme 1.

[Reaction Formula 1]

As shown in Scheme 1, epichlorohydrin can be used as the epihalohydrin.

In some embodiments, a basic catalyst may be used in the reaction step of epihalohydrin and 2-mercaptoethanol. For example, in the case of synthesizing a tetrafunctional polythiol compound, examples of the basic catalyst include a tertiary amine such as triethyl amine, a quaternary ammonium salt, triphenylphosphine, a trivalent chromium compound, and the like. In the case of synthesizing a trifunctional polythiol compound, an alkali metal-containing catalyst such as sodium hydroxide or potassium hydroxide may be used.

According to Scheme 1, for example, a preliminary polyol compound having a diol compound form containing a sulfide bond can be formed.

For example, the content of 2-mercaptoethanol may be 0.5 to 3 mol, preferably 0.7 to 2 mol, more preferably 0.9 to 1.1 mol, per 1 mol of epihalohydrin. The basic catalyst may be used in an amount of 0.001 to 0.1 mol, 0.005 to 0.03 mol, more preferably 0.007 to 0.015 mol, per 1 mol of epihalohydrin.

Step S10 can be performed with the reactor sufficiently cooled through refrigerant circulation to suppress excessive rise in reaction heat due to, for example, the ring opening reaction of epihalohydrin.

In some embodiments, step S10 is performed at a first temperature, which may be in the range of about 0° C. to 20° C., preferably 15° C. or less, or 5° C. to 15° C.

For example, at step S20, a metal sulfide may be added to the preliminary polyol compound and the temperature may be increased to a second temperature higher than the first temperature to produce a polyol intermediate according to the following reaction scheme 2.

[Reaction Formula 2]

As illustrated in Scheme 2, the sulfide bond-containing diol compounds can be further reacted with each other via the metal sulfide to obtain a polyol intermediate including a tetrafunctional polyol compound.

The above metal sulfide includes an alkali metal sulfide, and Na ₂ S can be used as shown in Scheme 2. For example, a polyol intermediate can be formed when an aqueous metal sulfide solution is added and stirred.

According to exemplary embodiments, after the metal sulfide is added, the temperature may be increased to the second temperature and stirred. The second temperature may be about 40° C. to 95° C. Preferably, the second temperature may exceed 50° C. In one embodiment, the second temperature may be about 55° C. to 90° C., more preferably, 60° C. to 90° C.

For example, the metal sulfide may be added dropwise at an intermediate temperature, for example, in the range of 20° C. to 25° C., which is increased from the first temperature. After the adding is completed, stirring may be performed by increasing the temperature from the intermediate temperature to the second temperature.

The heat of reaction can be secured through the above-mentioned increased second temperature. Accordingly, the amount of unreacted residual substances generated in step S10 can be appropriately controlled. Thus, the amount of unreacted residual substances can be more effectively controlled or reduced.

For example, in step S10, unreacted residues can generate a large amount of high molecular weight sub-compounds such as oligomers through self-aggregation or self-reaction. However, during the production of a polyol intermediate by introducing metal sulfide, sufficient heat of reaction can be secured to induce additional reactions of the unreacted residues, and accordingly, the amount of the sub-compounds can be appropriately controlled.

For example, by controlling the second temperature to the above-described range, the amount of the sub-compound can be maintained at a peak area (%) of 2.5% or less, preferably 1.5% to 2.5%, of the retention time in the range of 34 to 40 minutes of the HPLC analysis graph, and the above-described peak area ratio can be efficiently secured.

For example, in step S30, the polyol intermediate can be reacted with thiourea. Accordingly, an isothiouronium salt can be obtained according to exemplary embodiments.

Acidic reflux can be used to form isothiocyanate salts. Acidic compounds such as hydrochloric acid, hydrobromic acid, iodic acid, sulfuric acid, and phosphoric acid can be used to form acidic compounds.

The reflux temperature may be 90 to 120° C., preferably 100 to 120° C., and may be performed for about 1 to 10 hours. As described above, according to exemplary embodiments, as the additional reaction of the additionally added epihalohydrin is performed at the elevated second temperature in step S20, the unreacted residual material may be reduced or maintained at an appropriate amount.

Accordingly, even under the above high temperature reflux conditions, excessive generation of by-products is suppressed, and an appropriate reaction rate of the polythiol composition can be maintained.

For example, in step S40, the isothiouronium salt can be converted into a polythiol-based compound. According to exemplary embodiments, the isothiouronium salt can be hydrolyzed under basic conditions to produce a polythiol-based compound.

The S30 and S40 steps described above may include thiolation, as exemplified by Scheme 3 below.

[Reaction Formula 3]

For example, a basic aqueous solution can be added to a reaction solution containing an isothiouronium salt to cause hydrolysis. The basic aqueous solution can include an alkali metal hydroxide and/or an alkaline earth metal hydroxide, such as NaOH, KOH, LiOH, Ca(OH) ₂ , etc.

In one embodiment, the reaction solution containing the isothiouronium salt may be cooled to a temperature of 20 to 60°C, preferably 25 to 55°C, more preferably 25 to 50°C, and then the basic aqueous solution may be added.

In one embodiment, an organic solvent may be added prior to adding the basic aqueous solution. An organic solvent having low reactivity or substantially no reactivity and a boiling point exceeding the thiolation reaction temperature may be used so that a stable thiolation reaction proceeds.

Examples of the organic solvent include toluene, xylene, chlorobenzene, dichlorobenzene, etc., and toluene may be preferably used considering reaction stability and toxicity from the organic solvent.

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 contained in the polythiol compound can be removed, and the transparency of the optical material manufactured from the polythiol composition can be improved. Thereafter, additional processes such as drying and filtration can be performed.

In one embodiment, the aqueous layer can be separated or removed through layer separation after the hydrolysis process. An acid solution can be added to the obtained organic phase solution, and acid washing can be performed at a temperature of about 20° C. to 50° C., preferably about 30° C. to 40° C., for 20 minutes to 1 hour, or for 20 minutes to 40 minutes.

After the acid washing, a washing process can be performed by adding degassed water in which the dissolved oxygen concentration is adjusted to 5 ppm or less, preferably 3 ppm or less, and more preferably 2 ppm or less. The washing process can be performed 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 washing process can be repeated two or more times, and for example, can be performed three to six times.

After the above acid washing and water washing processes, the remaining organic solvent and moisture can be removed by heating under reduced pressure conditions, and then filtered through a filter to obtain a high-purity polythiol compound.

In some embodiments, the moisture remaining in the polythiol compound or polythiol composition may be 1,000 ppm or less, preferably 100 ppm to 500 ppm, more preferably 150 to 400 ppm.

In some embodiments, the GPC (Gel Permeation Chromatography) purity of the polythiol composition can be greater than or equal to 78%. For example, the GPC purity of the polythiol composition can be from 78% to 85%. Preferably, the GPC purity can be from 80% to 85%, more preferably from 80% to 84%.

In some embodiments, the liquidus refractive index of the polythiol composition at 25° C. may be from 1.645 to 1.648, preferably from 1.645 to 1.647, more preferably from 1.6450 to 1.6465.

In some embodiments, the thiol value (SHV) of the polythiol composition may be about 96.0 g/eq. to 98.5 g/eq. Preferably, the SHV may be about 96.0 g/eq. to 97.0 g/eq.

SHV can be measured by dividing the sample weight by the iodine equivalent consumed when titrating a polythiol composition sample using a 0.1N iodine standard solution.

According to the above-described embodiments, the production of sub-compounds can be controlled through the split introduction of epihalohydrin. However, the present application is not limited to the above-described manufacturing method, and the sub-compound may be separately introduced into the polythiol composition in an amount corresponding to the peak region of the above-described range. In addition, the amount of the sub-compound can be controlled through other process conditions such as reaction temperature, reaction time, etc., in addition to epihalohydrin.

According to one aspect of the present application, an optical composition (e.g., an optical polymerizable composition) comprising the polythiol composition described above is provided.

The optical polymerizable composition may include the polythiol composition and an isocyanate compound. The polythiol composition may include the main polythiol compound and the sub-compound described above.

The above isocyanate compound may include a compound that can be used as a monomer for polythiourethane synthesis. In a preferred embodiment, the isocyanate compound may include 1,3-bis(isocyanatomethyl)cyclohexane, hexamethylene diisocyanate, isophorone diisocyanate, xylene diisocyanate, toluene diisocyanate, and the like. These may be used alone or in combination of two or more.

The optical composition may further include additives such as a release agent, a reaction catalyst, a heat stabilizer, an ultraviolet absorber, a blueing agent, etc.

Examples of the above-mentioned releasing agents include fluorine-based nonionic surfactants having a perfluoroalkyl group, a hydroxyalkyl group, or a phosphate ester group; silicone-based nonionic surfactants having a dimethylpolysiloxane group, a hydroxyalkyl group, or a phosphate ester group; alkyl quaternary ammonium salts such as trimethyl cetyl ammonium salt, trimethylstearyl, dimethylethyl cetyl ammonium salt, triethyldodecyl ammonium salt, trioctylmethyl ammonium salt, and diethylcyclohexadodecyl ammonium salt; and acidic phosphate esters. These may be used alone or in combination of two or more.

As the above reaction catalyst, a catalyst used in the above polythiourethane resin polymerization reaction can be used. For example, dialkyl tin halide catalysts such as dibutyltin dichloride and dimethyltin dichloride; dialkyl tin dicarboxylate catalysts such as dimethyltin diacetate, dibutyltin dioctanoate and dibutyltin dilaurate; dialkyl tin dialkoxide catalysts such as dibutyltin dibutoxide and dioctyltin dibutoxide; dialkyl tin dithioalkoxide catalysts such as dibutyltin di(thiobutoxide); dialkyl tin oxide catalysts such as di(2-ethylhexyl)tin oxide, dioctyltin oxide and bis(butoxydibutyltin)oxide; dialkyl tin sulfide catalysts, etc. can be used. These can be used alone or in combination of two or more.

Examples of the above ultraviolet absorbers include benzophenone compounds, benzotriazole compounds, salicylate compounds, cyanoacrylate compounds, and oxanilide compounds. Examples of the above heat stabilizers include metal fatty acid salt compounds, phosphorus compounds, lead compounds, and organotin compounds. These may be used alone or in combination of two or more.

The above bluing agent may be included as a color control agent of an optical material manufactured from the polythiourethane resin. For example, the bluing agent may have an absorption band in a wavelength band from orange to yellow in the visible light range.

Examples of the bluing agent include dyes, fluorescent whitening agents, fluorescent pigments, inorganic pigments, etc., and may be appropriately selected according to the properties required for the optical product to be manufactured, resin color, etc. When a dye is used as the bluing agent, for example, a dye having a maximum absorption wavelength of 520 to 600 nm, preferably 540 to 580 nm, may be used. An anthraquinone dye may be preferably used.

The polythiourethane resin can be produced through a polymerization reaction of the polythiol-based compound and the isocyanate-based compound included in the above polythiol composition, and the polymerization reaction speed can be adjusted or controlled through the sub-compound included in the above-described polythiol composition.

Accordingly, an optical product can be manufactured that prevents yellowing or whitening, suppresses the occurrence of striae, and maintains uniform and improved optical properties for a long period of time.

In some embodiments, the main polythiol compound may be included in an amount of about 40 to 60 wt%, the isocyanate compound may be included in an amount of about 40 to 60 wt%, and the above-described additive may be included in an amount of about 0.01 to 1 wt% of the total weight of the optical composition.

In some embodiments, the reaction rate of the optical composition included in the mathematical formula 1 described below can be maintained in a range of 0.15 to 0.30, preferably in a range of 0.15 to 0.25, more preferably in a range of 0.15 to 0.23 by the sub-compound.

According to one aspect of the present application, an optical product manufactured using the optical composition described above can be provided.

For example, the polymerizable composition may be degassed under reduced pressure and then injected into a mold for forming an optical material. Mold injection may be performed at a temperature range of, for example, 20 to 40°C, preferably 20 to 35°C.

After mold injection, the temperature may be gradually increased to allow the polymerization reaction of the polythiourethane resin to proceed. The polymerization temperature may be 20°C to 150°C, preferably 25°C to 125°C. For example, the maximum polymerization temperature may be 100°C to 150°C, preferably 110°C to 140°C, and more preferably 115°C to 130°C.

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

For example, a lens having uniform optical properties and mechanical properties can be easily obtained by appropriately controlling the reaction rate within the above temperature range.

After polymerization is completed, the polymerized polythiourethane resin can be separated from the mold to obtain an optical product. In one embodiment, a curing process can be further performed after separation from the mold. The curing process can be performed at a temperature of 100° C. to 150° C., preferably 110° C. to 140° C., and more preferably 115° C. to 130° C., for about 1 hour to 10 hours, preferably 2 hours to 8 hours, and more preferably 3 hours to 6 hours.

The above optical products can be manufactured in the form of eyeglass lenses, camera lenses, light-emitting diodes, etc. depending on the mold shape.

The refractive index of the optical product can be controlled depending on the type and/or content ratio of the polythiol-based compound and the isocyanate-based compound used in the optical polymerizable composition. For example, the refractive index of the optical product can be controlled 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, and preferably in the range of 1.65 to 1.75 or in the range of 1.69 to 1.75.

In some embodiments, the glass transition temperature (Tg) of the optical product may be from 95° C. to 105° C., preferably from 100° C. to 105° C., more preferably from 100° C. to 104° C.

The above optical products may be improved by adding surface treatments such as anti-fouling, color imparting, hard coat, surface polishing, hardening, etc.

Hereinafter, the embodiments provided in the present application will be further described with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are only illustrative of the present invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications to the embodiments are possible within the scope and technical idea of the present invention, and it is natural that such changes and modifications fall within the scope of the appended claims.

Example 1

1) Synthesis of tetrafunctional polythiol compounds

Into the reactor, 60.0 parts by weight of water, 0.3 parts by weight of triethylamine, and 73.0 parts by weight of 2-mercaptoethanol (2-ME) were added, the reactor was cooled to 0°C, and 88.2 parts by weight of epichlorohydrin (ECH) was slowly added dropwise at a temperature of 15°C or lower to allow the first reaction to proceed.

Next, 148.7 parts by weight of a 25% sodium sulfide aqueous solution (Na ₂ Sㆍ9H ₂ O) was slowly added dropwise at 25°C, the temperature was increased to the second temperature described in Table 1, and the mixture was stirred for 3 hours. Thereafter, 486.8 parts by weight of 36% hydrochloric acid and 177.8 parts by weight of thiourea were added, and the mixture was stirred for 3 hours under reflux at 110°C to proceed with the thiuronium chloride reaction.

After the obtained reaction solution was cooled to 50°C, 305.6 parts by weight of toluene and 332.6 parts by weight of 50% NaOH were added, and hydrolysis was performed at 40 to 60°C for 3 hours.

After layer separation for 1 hour, discard the water layer. 120 parts by weight of 36% hydrochloric acid was added to the obtained toluene solution, and acid washing was performed once at 33 to 40°C for 30 minutes. After acid washing, 250 parts by weight of degassed water (dissolved oxygen concentration 2 ppm) was added, and washing was performed four times at 35 to 45°C for 30 minutes. After removing toluene and residual moisture under heating and reduced pressure, it was filtered through a PTFE type membrane filter to obtain the chemical formula

140 parts by weight of a polythiol composition containing a tetrafunctional polythiol compound as a main component was obtained.

2) Production of optical polymeric compositions and lenses

As described above, 49.0 parts by weight of the polythiol composition, 51.0 parts by weight of xylene diisocyanate, 0.01 parts by weight of dibutyl tin chloride, and 0.1 parts by weight of a phosphate ester release agent from ZELEC® UN Stepan were uniformly mixed, and then a defoaming process was performed at 600 Pa for 1 hour, thereby producing an optical polymerizable composition.

Thereafter, the composition filtered through a 3 μm Teflon filter was injected into a mold mold including a glass mold and a tape. The mold mold was slowly heated from 25° C. to 120° C. at a rate of 5° C. per minute, and polymerization was performed at 120° C. for 18 hours. After completion of polymerization, the mold mold was separated, and then further cured at 120° C. for 4 hours to produce a lens sample.

Example 2-6 and comparative examples

A polythiol composition and a lens sample were prepared by the same process as in Example 1, except that the second temperature was changed after the addition of the sodium sulfide aqueous solution, as described in Table 1 below.

In Comparative Example 1, a polythiol composition and a lens sample were prepared using the same process as in Example 1, except that the composition was stirred at 25°C after adding an aqueous sodium sulfide solution.

Experimental example

(1) HPLC analysis graph content analysis

In the polythiol compositions according to the examples and comparative examples, the peak area (%) of the sub-compound measured in the range of the retention time of 34 minutes to 40 minutes was measured through HPLC analysis performed under the following conditions.

<HPLC analysis conditions>

i) Equipment: Agilent 1260 Infinity Ⅱ

ii) Column: ZORBAX Eclipse Plus C18, 5um 4.6×250mm

iii) Mobile phase gradient: Acetonitrile (0.1% Formic Acid)：Water (0.01M Ammonium Formate) = 35~100：65~0

iv) Solvent: Acetonitrile (0.1% Formic Acid)

v) Wavelength: 230nm

vi) Flow rate: 1.0 ml/min, injection volume: 20 μl, sample pretreatment: sample: solvent = 0.1 g: 10 g

Figures 1 to 3 are images of high-performance liquid chromatography (HPLC) analysis graphs of polythiol compositions manufactured according to comparative examples and examples.

Specifically, FIGS. 1 and 2 are HPLC analysis graphs of Examples 3 and 4, respectively, and FIG. 3 is an HPLC analysis graph of Comparative Example 1. In FIGS. 1 to 3, the main peak corresponding to the main polythiol compound is indicated by an arrow, and the peaks corresponding to the sub-compounds in the retention time range of 34 to 40 minutes are indicated by dotted circles.

(2) Evaluation of thiol value (SHV)

About 0.1 g of the polythiol compositions prepared in the examples and comparative examples were added to a beaker, 25 mL of chloroform was added, and the mixture was stirred for 10 minutes. Then, 10 mL of methyl alcohol MeOH was added, and the mixture was stirred again for 10 minutes. The solution was titrated using a 0.1 N iodine standard solution, and the SHV was measured according to the following equation 1 (theoretical value: 91.7).

[Formula 1] SHV (g/eq.) = sample weight (g) / {0.1 x amount of iodine consumed (L)}

(3) Liquid refractive index

The refractive index at 25°C of the polythiol compositions synthesized in the examples and comparative examples was measured using a liquid refractometer (RA-600 (Kyoto Electronics Co., Ltd.)).

(4) GPC purity

The purity of the polythiol compositions synthesized in the examples and comparative examples was measured through gel chromatography analysis performed under the following conditions using an APC system (Waters).

i) Column: Acquity APC XT Column 45A (4.6*150mm)x2,

ii) Mobile phase: THF

iii) Flow rate: 0.5mL/min,

iv) Total driving time: 10 minutes,

v) Injection volume: 10 ㎕

vi) Detector: RID 40℃

(5) Macley evaluation

As described above, using the polymerizable compositions according to the examples and comparative examples, lens samples having a diameter of 75 mm and -4.00 D were manufactured, and a mercury lamp light source was transmitted through the manufactured lens samples, and the transmitted light was projected onto a white plate to determine whether or not striae were generated based on the presence or absence of a difference in brightness. The evaluation criteria are as follows.

○: Macri not observed

△: Fine partial ridges observed

×: Visibly observed with the naked eye

(6) Lens turbidity evaluation

For the lens samples of the examples and comparative examples manufactured as described above, the presence or absence of haze and opacity was visually confirmed by examining them with a projector in a darkroom.

The evaluation criteria are as follows.

○: No haze

△: Partial haze observed

×: Haze is clearly observed throughout

(7) Measurement of polymerization reaction rate (Reactivity Slope)

First, the standard viscosity (Standard cps) was confirmed with a viscosity standard solution (Brookfield, 1000 cps, 25 ^o C) using a non-contact viscometer of EMS-1000 (KEM). Then, 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, the X-axis represents time, the Y-axis represents viscosity, and the Y-axis is logarithmized to derive the reaction rate by formulating it as in the following mathematical formula 1.

[Mathematical formula 1]

Y = a × exp(b × X)

In mathematical expression 1, the a value represents the initial viscosity and the b value represents the reaction rate, and the measured values are rounded to the third decimal place.

(8) Measurement of glass transition temperature (Tg)

The glass transition temperature (Tg) of the lens samples of the examples and comparative examples was measured using the penetration method (50 g load, 0.5 mmФ pin tip, 10°C/min) using a thermomechanical analyzer (TMA Q400, TA instruments).

The evaluation results are shown in Tables 1 and 2 below.

After _Na2S addition
Highest temperature
(second temperature)
(℃) Polythiol composition properties SHV
(g/ea) Liquid
Refractive index 230nm
HPLC
area %
(34-40 minutes)(A) 230nm
HPLC
area %
(24-28 minutes)(B) peak
area
ratio
(A/B)*100
(%) GPC
water(%) Example 1 80 96.2 1.6459 1.98 84.21 2.35 83 Example 2 90 96.6 1.6462 1.85 84.45 2.19 83 Example 3 60 96.5 1.6459 2.10 83.79 2.51 82 Example 4 55 96.9 1.6463 2.21 82.40 2.68 81 Example 5 45 97.0 1.6463 2.50 81.20 3.08 80 Example 6 100 98.5 1.6475 1.41 80.82 1.74 78 Comparative Example 1 15 97.2 1.6467 3.51 79.80 4.40 78 Comparative Example 2 25 97.3 1.6468 3.11 80.18 3.88 78 Comparative Example 3 30 97.2 1.6470 2.58 80.97 3.19 80

Lens properties MacLee White turbidity reaction
speed Tg (℃) Example 1 ○ ○ 0.22 103 Example 2 ○ ○ 0.23 103 Example 3 ○ ○ 0.18 104 Example 4 ○ ○ 0.16 104 Example 5 ○ ○ 0.15 105 Example 6 △ ○ 0.26 100 Comparative Example 1 ○ × 0.11 108 Comparative Example 2 ○ × 0.12 106 Comparative Example 3 ○ × 0.14 105

Referring to Tables 1 and 2, for examples in which the peak areas detected at retention times ranging from 34 minutes to 40 minutes in the 230 nm HPLC analysis graph were 2.5% or less, the appropriate reaction rate was maintained while streaking and cloudiness were practically not observed.

For comparative examples in which the HPLC peak area exceeded 2.5%, a white turbidity phenomenon was observed as the polymerization reaction rate decreased excessively.

Claims (15)

Main polythiol compound; and
Containing a sub-compound having a molecular weight greater than that of the main polythiol compound;
A polythiol composition, wherein a peak area (%) in a retention time range of 34 minutes to 40 minutes of a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm corresponding to the above sub-compound exceeds 0% and is 2.5% or less based on the total peak area. A polythiol composition according to claim 1, wherein the peak area of the HPLC analysis graph in the retention time range of 34 minutes to 40 minutes is 1.5% to 2.5%. In claim 1, multiple peaks are detected in the retention time range of 34 to 40 minutes of the HPLC analysis graph,
A polythiol composition, wherein the sum of the areas of the above plurality of peaks exceeds 0% and is 2.5% or less. A polythiol composition according to claim 1, wherein the main polythiol compound comprises a tetrafunctional polythiol compound having a retention time in the range of 24 to 28 minutes in the HPLC analysis graph. A polythiol composition according to claim 4, wherein the tetrafunctional polythiol compound comprises a compound represented by C ₁₀ H ₂₂ S ₇ . In claim 5, the tetrafunctional polythiol compound is a polythiol composition comprising at least one of the compounds represented by the following chemical formulae 1-1 to 1-3:
[Chemical Formula 1-1]

[Chemical Formula 1-2]

[Chemical Formula 1-3]
. A polythiol composition according to claim 1, wherein the peak area (%) of the HPLC analysis graph in the retention time range of 24 to 28 minutes is 80 to 90%. A polythiol composition according to claim 1, wherein the peak area (%) of the HPLC analysis graph in the retention time range of 24 to 28 minutes is 81 to 85%. In claim 1, a polythiol composition having a peak area ratio defined by the following formula 1 of 1.5% to 3.1%:
[Formula 1]
Peak Area Ratio (%) = (A/B)*100
(In Equation 1, A is the peak area (%) included in the retention time range of 34 to 40 minutes in the HPLC analysis graph, and B is the peak area (%) included in the retention time range of 24 to 28 minutes in the HPLC analysis graph). A polythiol composition comprising a main polythiol compound and a sub-compound having a molecular weight greater than that of the main polythiol compound, wherein a peak area (%) of a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm corresponding to the sub-compound in a range of retention times of 34 minutes to 40 minutes exceeds 0% and is 2.5% or less based on the total peak area; and
An optical composition comprising an isocyanate compound. An optical composition according to claim 10, wherein a peak area of the HPLC analysis graph in the retention time range of 34 minutes to 40 minutes is 1.5% to 2.5%. An optical composition according to claim 10, wherein the main polythiol compound comprises a tetrafunctional polythiol compound having a retention time in the range of 24 minutes to 28 minutes of the HPLC analysis graph. In claim 12, an optical composition wherein the peak area ratio defined by the following formula 1 of the polythiol composition is 1.5% to 3.1%:
[Formula 1]
Peak Area Ratio (%) = (A/B)*100
(In Equation 1, A is the peak area (%) included in the retention time range of 34 to 40 minutes in the HPLC analysis graph, and B is the peak area (%) included in the retention time range of 24 to 28 minutes in the HPLC analysis graph). Comprising a polymer of a polythiol composition and an isocyanate compound,
The above polythiol composition
An optical product comprising a main polythiol compound and a sub-compound having a molecular weight greater than that of the main polythiol compound, wherein a peak area (%) of a high-performance liquid chromatography (HPLC) analysis graph obtained at a wavelength of 230 nm corresponding to the sub-compound in a retention time range of 34 minutes to 40 minutes exceeds 0% and is 2.5% or less based on the total peak area. An optical product according to claim 14, having a glass transition temperature in the range of 95°C to 105°C.

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