Polythiols, methods for making them, and polymerizable compositions

Abstract

Provided is a polythiol composition comprising: a) a polythiol according to Formula (I) where each n is independently 2 to 4; and b) a polythiol according to Formula (II) where each n is independently 2 to 4 and m is 1 or 2. Also provided are methods for preparing the above polythiol compositions, as well as polymerizable compositions comprising the polythiol composition and an aliphatic polyisocyanate. [Formula 1] JPEG2026506064000018.jpg85110

Description

[Technical Field]

[0001] The present disclosure is directed to polythiols, methods for making them, and polymerizable compositions containing them. [Background technology]

[0002] Polythiols are used to form optical articles with good thermomechanical properties by reacting with polyisocyanate compounds to form polythiourethane materials. Polythiols with high sulfur content facilitate the production of optical articles with high refractive indexes. There are many methods for synthesizing polythiols, but most techniques involve two or more reaction process steps.

[0003] Thioacetals have a high sulfur-to-carbon ratio (resulting in a higher refractive index than typical aliphatic polythiols). Furthermore, thioacetals are abundant in the chemical industry, therefore inexpensive, often derived from biobased sources, generally favorable in terms of environmental and safety concerns, and can be prepared from aldehydes, which offer higher selectivity and reactivity (compared to alcohols) for the formation of thioacetals. However, this high reactivity also increases the likelihood of undesirable reactions, such as oligomerization, polymerization, and crosslinking, when dithiols or higher thiols react with dialdehydes or higher aldehydes via step growth.

[0004] To circumvent this problem, it has been proposed to employ a protection / deprotection reaction scheme, but this adds steps and cost to the production of polythiols. Furthermore, a mixture of dithiols, monothiols, and unprotected thiols is unavoidable during protection, necessitating an intermediate purification step, further increasing the cost and complexity of the polythiol synthesis process. Another approach exploits the selectivity of thiols over alcohols by reacting mercaptohydroxy compounds with aldehydes to produce polyols as intermediate compounds that can be converted to polythiols by conventional means. Again, this adds complexity, time, and cost to the synthesis of polythiols.

[0005] There is a need to provide polythiols that can be prepared using minimal reaction process steps, without requiring the removal of by-products or intermediates, and that are suitable for preparing high refractive index polymers. Summary of the Invention

[0006] 1. A polythiol composition comprising: a) a polythiol according to formula (I), [ka] wherein each n is independently 2 to 4; and b) a polythiol according to formula (II), [ka] wherein each n is independently 2 to 4 and m is 1 or 2.

[0007] Also provided is a method for preparing the polythiol composition, comprising: a. preparing a reaction mixture comprising a dithiol, a dialdehyde, and a catalyst, wherein the molar ratio of dithiol to dialdehyde is at least 4:1; b. subjecting the reaction mixture to conditions sufficient to form a polythiol composition.

[0008] 1. A polymerizable composition comprising: a) the polythiol composition described above; b) an aliphatic polyisocyanate, wherein the equivalent ratio of isocyanate groups (—NCO) in the polyisocyanate b) to thiol (—SH) groups in the polythiol composition a) is 1:0.9 to 1:1.1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Other than in the working examples, or where otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and the like used in the specification and claims should be understood as being modified in all instances by the term "about," even when the term "about" does not explicitly appear. Accordingly, unless otherwise indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0010] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0011] Any numerical range recited herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, i.e., having minimum values ​​equal to or greater than 1 and maximum values ​​equal to or less than 10.

[0012] Plural forms include the singular, and vice versa. For example, the singular forms "a," "an," and "the" include plural referents unless expressly and unambiguously limited to one referent. For example, if a composition is described in terms of "a" polythiol compound or "an" isocyanate, the plural (including mixtures of such compounds) can be used.

[0013] The present disclosure provides polythiols suitable for use in preparing optical articles exhibiting high refractive index. It has been discovered that when an appropriate excess of a dithiol is reacted with a dialdehyde, a mixture of products is obtained that is suitable for use in forming optical materials / polythiourethanes, such that removal of by-products is unnecessary. The reaction to form the polythiol proceeds in a single step, performed in one pot, without the need for protecting groups or intermediates that must be further reacted or converted to the desired polythiol. Therefore, a wide range of compounds containing a thioacetal / ketal core can be easily synthesized using the methods described herein.

[0014] The polythiol composition is a) a polythiol according to formula (I), [ka] wherein each n is independently 2 to 4; and b) a polythiol according to formula (II), [ka] wherein each n is independently 2 to 4 and m is 1 or 2. Note that each of components a) and b) may comprise one or more different polythiols having the structures of formulas (I) and (II).

[0015] In one particular example, the polythiol composition comprises c) a polythiol according to formula (III): [ka] The polythiol composition may further comprise a polythiol having the formula (III), wherein n is 2 to 4. Often, n=2 in Formula (III). However, polythiol c) may comprise one or more different polythiols having the structure of Formula (III). When the polythiol composition comprises polythiol c) of Formula (III), polythiol c) may be present in an amount of at least 10 percent, e.g., at least 20 percent, and up to 50 percent, e.g., up to 40 percent, based on the total polythiol in the composition, as determined by the LC-MS procedure defined below. For example, a polythiol according to Formula (III) may be present in the composition in an amount of 10 to 50 percent, or 10 to 40 percent, or 20 to 50 percent, or 20 to 40 percent, based on the total polythiol in the composition, as determined by the LC-MS procedure defined below. The composition percentage reported from this procedure refers to the area under the curve of the specified compound relative to the sum of the areas under the curve of all major UV peaks (greater than 5%) observed in the LC-MS chromatogram. The proportions of each compound are close to, but not exactly, the weight percent, in part because the absorbance of a given compound may not be directly proportional to its weight.

[0016] The polythiol composition can be prepared from a reaction mixture containing a dithiol, a dialdehyde, and a catalyst. Exemplary dithiols have a chain length (e.g., greater than 5 atoms) sufficient to inhibit cyclization. Particularly suitable dithiols include those according to formula (III), such as 2,2'-thiobis(ethane-1-thiol) or 2,2'-(ethane-1,2-diylbis(sulfanediyl))bis(ethane-1-thiol). Higher polythiols, such as tri- and tetra-thiols, can also be included in the reaction mixture, but in amounts small enough to minimize the formation of higher molecular weight oligomers.

[0017] Suitable dialdehydes include low molecular weight aliphatic dialdehydes, which maximize the refractive index and reduce undesired oligomerization in the polythiourethane polymer body; aromatic dialdehydes can also be used. Difunctional ketocarbonyl compounds (aliphatic or aromatic) can also be used, but they exhibit lower reactivity toward thioketal formation and a higher carbon-to-carbonyl ratio, resulting in a decrease in the refractive index in the polythiourethane polymer body. Polyaldehyde / ketone compounds can also be used, but they exhibit a greater tendency to form high molecular weight oligomers. Specific examples of suitable dialdehydes include glyoxal, benzene-1,2-dicarbaldehyde, benzene-1,3-dicarbaldehyde, benzene-1,4-dicarbaldehyde, cyclohexane-1,4-dicarbaldehyde, succinic dialdehyde, or malondialdehyde.

[0018] As described above, when a suitable excess of dithiol is reacted with a dialdehyde, a product mixture is obtained that remains soluble and suitable for forming an optical material (i.e., a polythiourethane), such that removal of by-products is unnecessary. Typically, the molar ratio of dithiol to dialdehyde in the reaction mixture is at least 4:1, or at least 6:1, for example, 6:1 to 12:1.

[0019] Suitable catalysts for use in the reaction mixture include, for example, acid catalysts. Both inorganic and organic protonic (Brønsted) acids can be used in quasi-equimolar loadings relative to the dialdehyde (such as toluenesulfonic acid or hydrochloric acid). Specifically, Lewis acid catalysts such as lithium tetrafluoroborate are suitable, and other Lewis acids (organometallic compounds, (alkyl)metal chlorides and triflates, organoboranes, etc.) are also suitable. The amount of catalyst in the reaction mixture may vary and may depend on various factors, such as the type and amount of reactive compound used, as well as the desired reaction conditions, reaction rate, and degree of reaction. Typically, approximately equimolar loadings of Lewis acid relative to the dialdehyde are particularly suitable.

[0020] The reaction mixture may further include an organic solvent that is unlikely to react with the carbonyl functionality, typically a polar aprotic solvent known in the art. Examples include acetonitrile, tetrahydrofuran, dihalomethanes, trihalomethanes, aprotic polyethers, and mixtures thereof. The solvent may be present in an amount of 25 to 95 weight percent, based on the total weight of the reaction mixture.

[0021] After the reaction mixture is prepared, it is subjected to conditions sufficient to form a polythiol composition in a one-step, one-pot reaction. The reaction may be carried out at ambient temperature. Ambient conditions mean that the reaction proceeds without the aid of heat or other energy. Ambient temperatures typically range from 60 to 90°F (15.6 to 32.2°C), such as typical room temperature of 72°F (22.2°C). Reaction conditions may include heating to temperatures of 30 to 85°C, e.g., 40 to 75°C, or 55 to 65°C, for 1 to 24 hours, e.g., 10 to 15 hours. Exemplary reaction conditions are 58 to 62°C for 11 to 13 hours. Water liberated from the carbonyl species may be actively removed or removed from the reaction by the addition of a drying agent or by distillation, but is typically not necessary for the reaction to proceed.

[0022] The polythiol composition may have a thiol equivalent weight of at least 100 g / eq, or at least 110 g / eq, or at least 120 g / eq, and up to 250 g / eq, e.g., up to 220 g / eq, or up to 200 g / eq, or up to 160 g / eq, based on the total weight of polythiol present in the composition. For example, the polythiol composition may have a thiol equivalent weight of 100 to 250 g / eq, or 100 to 220 g / eq, or 100 to 200 g / eq, or 100 to 160 g / eq, or 110 to 250 g / eq, or 110 to 220 g / eq, or 110 to 200 g / eq, or 110 to 160 g / eq, or 120 to 250 g / eq, or 120 to 220 g / eq, or 120 to 200 g / eq, or 120 to 160 g / eq, based on the total weight of the polythiol present in the composition.

[0023] Typically, the polythiol of formula (I) may be present in greater than 20 percent, e.g., at least 25 percent, or at least 30 percent, and up to 50 percent, or up to 45 percent, based on the total polythiol in the composition as determined by the LCMS procedure defined below. For example, the polythiol of formula (I) may be present in the polythiol composition in an amount of 20 to 50 percent, or 20 to 45 percent, or 25 to 50 percent, or 25 to 45 percent, or 30 to 50 percent, or 30 to 45 percent, based on the total polythiol in the composition as determined by the LCMS procedure defined below.

[0024] The use of the above-mentioned reactants in their given ratios allows for the formation of polythiols having a thioacetal "core," which provides the advantages discussed above for polythiourethane polymer bodies. Thus, the above-described polythiol compositions have refractive indices (n) greater than or equal to 1.60. e 20The present invention is useful in polymerizable compositions for forming optical polymer bodies having a thiol group, a thiol group, a methyl ...

[0025] The polyisocyanate is aliphatic, but may also include aromatic polyisocyanates. Isocyanate-functional uretdiones, allophanates, biurets, and isocyanurates are also suitable. Diisocyanates and triisocyanates, such as isocyanurates of diisocyanates, are often used. Isocyanate-functional prepolymers, such as the reaction products of polyisocyanates with polyols, can also be used. Mixtures of polyisocyanates can be used.

[0026] Polyisocyanates can be prepared from a variety of isocyanate-containing materials. Other examples of suitable polyisocyanates include trimers prepared from the following diisocyanates: 4,4'-methylene-bis(cyclohexyl isocyanate), isophorone diisocyanate, an isomeric mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, and 4,4'-diphenylmethylene diisocyanate.

[0027] Suitable diisocyanates include 4,4'-methylene-bis(cyclohexylisocyanate) (i.e., 4,4'-diisocyanatodicyclohexylmethane), isophorone diisocyanate, an isomeric mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, and 1,6-hexamethylene diisocyanate. Typically, the equivalent ratio of isocyanate groups (-NCO) in polyisocyanate b) to thiol (-SH) groups in polythiol composition a) is 1:0.9 to 1:1.1, often 1:1.

[0028] Examples of aromatic polyisocyanates that may be used in addition to the aliphatic polyisocyanates include toluene diisocyanate, tetramethylxylylene diisocyanate, and m-xylylene diisocyanate. Uretdiones, allophanates, biurets, isocyanurates, and isocyanate-functional prepolymers prepared therefrom are also suitable.

[0029] The polythiol composition may further include urethanization catalysts, color correction dyes, mold release agents, degassing agents, UV absorbers, etc., as known in the art, present in art-recognized amounts. The amount of each additive will vary depending on the desired performance and intended use of the article.

[0030] Suitable urethanization catalysts can vary, for example, suitable urethanization catalysts can include those catalysts that are useful in the reaction of NCO and SH-containing materials to form thiourethanes. Non-limiting examples of suitable catalysts can be found in Ullmann's Encyclopedia of Industrial Chemistry, 5 th The catalyst may be selected from the group consisting of Lewis bases, Lewis acids, and insertion catalysts, as described in "The Journal of Polymer Science and Technology, Vol. 1, No. 1, pp. 673 to 674, 1992. The catalyst may be a stannous salt of an organic acid, such as, but not limited to, stannous octoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin mercaptide, dibutyltin dimaleate, dimethyltin diacetate, dimethyltin dilaurate, dibutyltin dichloride, dimethyltin dichloride, 1,4-diazabicyclo[2.2.2]octane, and mixtures thereof. Alternatively, the catalyst may be zinc octoate, bismuth, or ferric acetylacetonate.

[0031] Further non-limiting examples of suitable catalysts include tin compounds such as dibutyltin oxide, phosphines, tertiary ammonium salts, and tertiary amines, such as, but not limited to, triethylamine, triisopropylamine, dimethylcyclohexylamine, N,N-dimethylbenzylamine, pyridine, and mixtures thereof. Amine compounds and alkyltin halide compounds are most commonly used and are most suitable when used in combination. Catalyst levels can vary depending on the type used. For example, organotin catalysts are typically present in amounts up to 1000 ppm, e.g., 100-1000 ppm, often about 250 ppm. Mixtures of two or more of the above catalysts are also suitable.

[0032] Polymerization of the above compositions results in the formation of a polymeric body that can be fabricated in the form of a shaped article, for example, by casting to form a sheet or by molding. The polymeric body resulting from polymerization of the polymerizable compositions of the present disclosure is a thermoset solid and, in some embodiments, is transparent.

[0033] The polymerizable composition may alternatively be sprayable, castable, extrudable, 3D printable, or moldable. Polymeric bodies prepared from the polymerizable composition are often used to form solid articles such as optical element(s) or optical device(s). As used herein, the term "optical" means relating to or pertaining to light and / or vision.

[0034] In the fabrication of optical articles, the polymerizable composition may be introduced into a mold of any desired shape at a temperature and for a time to form a polymeric body. After the components of the polymerizable composition are mixed to form a reaction mixture, it is typically introduced into the mold by injection. The mold, as described above, may have any shape desired for the final product. It is typically a lens mold, often a mold for an ophthalmic lens. The shaped article may then be released from the mold.

[0035] Optical articles can include ophthalmic elements and devices, as well as display elements and devices, windows, mirrors, and / or sheet products such as active and passive liquid crystal cell elements and devices. As used herein, the term "ophthalmic" means relating to or pertaining to the eye and vision. Non-limiting examples of ophthalmic elements include corrective and non-corrective (plano) lenses, including multivision lenses, which may be either single-vision lenses or segmented or non-segmented multivision lenses (such as, but not limited to, bifocal, trifocal, and progressive lenses), as well as other elements used to correct, protect, or enhance vision (cosmetically or otherwise), including, but not limited to, contact lenses, intraocular lenses, magnifying lenses, sun lenses, fashion lenses, sports masks, face shields, and goggles. As used herein, the term "display" means a visible or machine-readable representation of information in words, numbers, symbols, designs, or drawings. Non-limiting examples of display elements and devices include touchscreens, monitors, and screens containing security elements such as security marks. As used herein, the term "window" means an opening adapted to permit the transmission of radiation therethrough. Non-limiting examples of windows include automotive and aircraft transparency films, filters, shutters, and light switches. As used herein, the term "mirror" means a surface that specularly reflects incident light.

[0036] The polymeric bodies prepared from the polymerizable composition have a refractive index of at least 1.57, or at least 1.58, or at least 1.59, an Abbe number of at least 30, or at least 33, or at least 35, and a compressibility of at least 50 N / mm 2 , or at least 70N / mm 2 , or at least 90N / mm 2 The refractive index, Abbe number, and Fischer hardness value can be determined according to art-recognized methods. For example, the refractive index value (n e 20 ) and Abbe number may be determined using a Metricon Model 2010 Prism Coupler, Thin Film Thickness / Refractive Index Measurement System in accordance with the manufacturer's operation and maintenance guide, and Fischer hardness values ​​are determined in accordance with ISO 14577 using a Fischer Technologies H100C Microhardness Measurement System.

[0037] The following examples are intended to further illustrate the disclosed compositions.It is understood that the present disclosure herein is not necessarily limited to the examples described in this section.Components that are described elsewhere herein as suitable alternative materials for use in compositions, but are not demonstrated in the following examples, are expected to provide results comparable to their demonstrated counterparts.Unless otherwise indicated, all parts are by weight. [Example]

[0038] Definition / Method: Part 1. Example 1: Preparation of a Polythiol Composition Glyoxal (64.90 g, 0.45 mol of a 40 wt / wt% aqueous solution), 2,2'-thiobis(ethane-1-thiol) (482.8 g, 3.13 mol), and lithium tetrafluoroborate (75.4 g, 0.80 mol) were sequentially charged and dissolved in acetonitrile (1621 mL) to form a solution in a 5 L four-neck round-bottom flask. The reaction solution was heated to 60 °C for 12 h and then cooled to room temperature. The mixture phases were separated and the bottom layer containing the product was collected. This product layer was washed sequentially with two portions of acetonitrile, first 300 mL and then 150 mL, and the acetonitrile wash layer was discarded. The remaining acetonitrile-insoluble fraction was concentrated under vacuum at 50-60 °C to form a clear, viscous liquid product (206 g), which passed through a 5 μm filter. Prior to use, the polythiol mixture was dried under high vacuum for a minimum of 8 hours to remove residual moisture.

[0039] Part 2. Characterization of the polythiol composition of Example 1. Thiol equivalent weight was determined using the following procedure. A polythiol sample (0.0500–0.1000 g) was weighed to the nearest ten-thousandth on an analytical balance and dissolved in 30 mL of either tetrahydrofuran or a 60 / 40 wt / wt solution of toluene / isopropanol, depending on the solubility of the polythiol. One to three drops of pyridine were added to the solution, and the sample was then stirred at room temperature until dissolved. While stirring, the mixture was titrated in a 0.1 N solution of iodine in water using a Metrohm 865 Dosimat Plus until a distinct yellow color persisted. This process was repeated, and the SH equivalent weight was calculated using Equation (3) below and the average of the two results used in the calculation. It is recognized that certain polythiol mixtures used in the Examples / Comparative Examples may contain small amounts of residual hydroxyl functionality, potentially affecting the total active hydrogen equivalent weight and, therefore, the ratio of active hydrogen groups to isocyanate groups. However, this difference was expected to be negligible, and only the thiol equivalent weight was used to calculate the amount of isocyanate groups required to reach an approximately 1:1 ratio of active hydrogen groups to isocyanate groups.

number

[0040] The thiol equivalent weight of Example 1 was determined according to the procedure described and found to be 224 g / equivalent.

[0041] The products were also characterized by liquid chromatography coupled with mass spectrometry according to the following procedure ("LCMS procedure") to determine the amount of each polythiol component in the product mixture. The product mixture was diluted with tetrahydrofuran (THF) and analyzed by reversed-phase ultra-high pressure liquid chromatography with online UV / Vis and mass spectrometry detection. The product mixture was separated on a Dionex UHPLC with a Waters Cortecs UPLC C18 column with a 1.6 μm pore size and dimensions of 100 × 2.1 mm. The mobile phase was a gradient mixture of deionized water and acetonitrile ranging from 60% DI H2O / 40% acetonitrile at TO and increasing to 2% DI H2O / 98% acetonitrile by the end of the run. Analytes were detected using a Vanquish UV-Vis set at 230 nm. Mass spectrometry was performed on the UPLC effluent on a QExactive Mass Spectrometer in both full MS in AIF ESI positive mode and full MS in AIF ESI negative mode within the scan range of 133.4–2000 m / z. Data analysis was performed using Xcalibur 4.2 software. Again, the percent composition reported from this analysis refers to the area under the curve of the specified compound relative to the sum of the areas under the curve of all major UV peaks (>5%) observed in the LC-MS chromatogram.

[0042] The compositions according to this analysis are shown in Table 1. [Table 1] Part 3. Preparation of the curable composition. [Table 2]

[0043] Comparative Example CE-2: Optical Articles Cast from Cycloaliphatic Diisocyanates and Industry Standard Polythiols The ingredients of Charge 1 were added to a 250 mL flask equipped with a magnetic stir bar using a vacuum adapter. To this, Charges 2 and 3 were added. The mixture was placed under vacuum and degassed for approximately 30 minutes. The thiol mixture of Charge 4, calculated to achieve a 1:1 thiol:isocyanate equivalent ratio, was charged to the reaction flask, which was sealed and placed under vacuum again. The mixture was stirred at room temperature for approximately 2 hours, after which the temperature was raised to 60°C by placing the flask in an oil bath. After 5 minutes, the mixture was poured into a preheated (60°C) flat glass mold equipped with an approximately 3.5 mm thick rubber gasket spacer. The mold was placed in an oven initially set at 60°C. The oven temperature was increased to 140°C over 9.16 hours, held at this temperature for 5.16 hours, and finally decreased to 70°C over 1.16 hours. The oven was then turned off, the sample was allowed to return to room temperature, and it was removed from the mold. Using this same procedure and the same ratios of reagents, another polymer body mixture was prepared. This mixture was cast into a pre-assembled, completed Single Vision minus "-" magnification mold with a set center thickness of 2.2 mm. The same curing conditions were also used.

[0044] Comparative Example CE-3: Optical Article Cast from Aromatic Diisocyanate and Polythiol of Example 1 Charge 1 was added to a 250 mL flask equipped with a magnetic stir bar using a vacuum adapter. Charges 2 and 3 were also added to the flask. The mixture was placed under vacuum and degassed for approximately 35 minutes. Charge 4, calculated to achieve a 1:1 thiol:isocyanate equivalent ratio, was charged to the reaction flask and the vacuum was restored. The mixture immediately became homogeneous and was stirred at room temperature for approximately 15 minutes before being dispensed into a pre-assembled, completed single-vision minus "-" magnification mold with a set center thickness of 2.2 mm. The mold was placed in an oven initially set at 60°C. The oven temperature was increased to 140°C over 9.16 hours, held at this temperature for 5.16 hours, and finally decreased to 70°C over 1.16 hours. The oven was then turned off, the sample was allowed to return to room temperature, and it was removed from the mold.

[0045] Example 4: Optical Flat Sheets Cast from IPDI and Polythiol of Example 1 Charge 1 was added to a 100 mL round-bottom flask equipped with a magnetic stir bar and degassed under high vacuum for approximately 20 minutes. Charges 2 and 3 were added, and the flask was resealed and degassed again. Charge 4, a polythiol mixture calculated to achieve a thiol:isocyanate equivalent ratio of 1:0.99, was then added to the flask. The flask was once again sealed and placed under high vacuum. The reaction mixture was stirred at 60°C in an oil bath for approximately 30 minutes until it became homogeneous. The mixture was aged at 60°C for approximately 20 more minutes and then poured into a flat glass mold equipped with a rubber gasket spacer approximately 3.5 mm thick. The polymer body in the mold was initially transferred to an oven at ambient conditions. The oven temperature was increased to 140°C over 9.75 hours, held at this temperature for 5.16 hours, and finally decreased to 70°C over 1.16 hours. The oven was turned off, the samples were allowed to return to room temperature, and they were removed from the molds.

[0046] Example 5: Optical Articles Cast from Cycloaliphatic Diisocyanates and Polythiols of Claim 1 The ingredients of Charge 1 were added to a 250 mL flask equipped with a magnetic stir bar using a vacuum adapter. Charges 2 and 3 were also added to the same flask. This mixture was placed under vacuum and degassed for approximately 20 minutes. Charge 4, calculated to achieve a thiol:isocyanate equivalent ratio of 1:1.01, was charged to the reaction flask and the vacuum was restored. The mixture under vacuum was placed in a 60°C oil bath and aged for 60 minutes, during which time the mixture became homogeneous. The reaction mixture was dispensed into a pre-assembled, completed single vision minus "-" magnification mold with a set center thickness of 2.2 mm and a flat glass mold equipped with a rubber gasket spacer of approximately 3.5 mm thickness. The mold was first placed in an oven set at 60°C. The oven temperature was increased to 140°C over 9.16 hours, held at this temperature for 5.16 hours, and finally decreased to 70°C over 1.16 hours, then the oven was turned off, the samples were allowed to return to room temperature, and they were removed from their molds.

[0047] Example 6: Optical Articles Cast from Cycloaliphatic Diisocyanates and Polythiols of Claim 1 Having Low SH Equivalent Weights The ingredients of Charge 1 were added to a 250 mL flask equipped with a magnetic stir bar using a vacuum adapter. Charges 2 and 3 were added to the same flask. The mixture was placed under vacuum and degassed for approximately 50 minutes. Charge 4, a polythiol mixture calculated to achieve a thiol:isocyanate equivalent ratio of 1:1.04, was charged to the reaction flask and the vacuum was restored. The mixture was placed in a 60°C oil bath and aged for approximately 15 minutes, whereupon the mixture became homogeneous. After aging for approximately 30 minutes, the reaction mixture was dispensed into a pre-assembled, completed single vision minus "-" magnification mold with a set center thickness of 2.2 mm and a flat glass mold equipped with a rubber gasket spacer of a thickness equal to approximately 3.5 mm. The mold was initially placed in an oven set at 60°C. The oven temperature was increased to 140°C over 9.16 hours, held at this temperature for 5.16 hours, and finally decreased to 70°C over 1.16 hours, then the oven was turned off, the samples were allowed to return to room temperature, and they were removed from their molds.

[0048] Part 4. Evaluation of the polymer bodies of the Examples and Comparative Examples. Fischer microhardness (FMH) was determined by testing according to ISO 14577-07 using a FISHERSCOPE® H-100SMC (available from Fisher Technology, Inc.). The FMH of the polymer body was measured at a load of 300 mN after applying a load from 0 to 300 mN for 15 seconds. Results are the arithmetic mean of at least three measurements.

[0049] Glass transition temperatures were measured on a TA Instruments Q200 differential scanning calorimeter (DSC).

[0050] The refractive index was measured using a temperature-compensated Metricon Model 2010 / M Prism Coupler equipped with monochromatic light sources at 453, 543, and 633 nm. The Abbe number was calculated from the refractive index values ​​according to the following equations (1) and (2), where V D and V eare the Abbe values ​​for the Fraunhofer d-line and green mercury E-line, respectively, and n d , n F , n C , n e , n F’ , and n C’ are the refractive indices of the material at the Fraunhofer D, F, and C lines, the green mercury E line, and the blue and red cadmium lines, respectively. Refractive indices at wavelengths that were not directly measured were calculated from a best fit of the empirical data to the Cauchy equation.

number

number

[0051] Luminous transmittance and color were measured using a HunterLab Ultra Scan Pro spectrophotometer (available from Hunter Associates Laboratory, Inc.) according to ASTM E313-10° / D65 and manufacturer's instructions. The path length of the sheet sample is equal to the sample thickness. [Table 3-1] [Table 3-2]

[0052] As demonstrated above, Examples 4, 5, and 6 exhibit higher refractive indices than CE-2, which has a lower thiol equivalent weight content. In addition, the aromatic polyisocyanate of CE-3 forms a very soft polymer body with low luminous transmittance. Specifically, the above examples demonstrate that high refractive indices can be achieved with acceptable thermomechanical properties.

[0053] While particular examples have been described above for purposes of illustration, it will be apparent to those skilled in the art that many changes can be made to the details of the present disclosure without departing from the scope of the disclosure as defined in the appended claims. It is therefore understood that the disclosure is not limited to the particular embodiments disclosed, but that it is intended to cover modifications that are within the spirit and scope of the disclosure as defined by the appended claims.

Claims

1. 1. A polythiol composition comprising: a) a polythiol according to formula (I), 【Chemistry 1】 wherein each n is independently 2 to 4; and b) a polythiol according to formula (II), 【Chemistry 2】 wherein each n is independently 2 to 4 and m is 1 or 2.

2. 10. The polythiol composition of claim 1, wherein the polythiol composition has a thiol equivalent weight of 100 to 250 g / eq, based on the total weight of polythiol present in the composition.

3. The polythiol composition of claim 2, wherein the polythiol composition has a thiol equivalent weight of 120 to 160 g / eq, based on the total weight of polythiol present in the composition.

4. c) a polythiol according to formula (III): 【Transformation 3】 The polythiol composition of any one of claims 1 to 3, further comprising a polythiol wherein n is 2 to 4.

5. The polythiol composition of claim 4 , wherein n=2 in formula (III).

6. 6. The polythiol composition of claim 5, wherein the polythiol according to formula (III) is present in the composition in an amount of 10 to 50 percent, based on the total polythiols in the composition, as determined by an LCMS procedure.

7. 7. The polythiol composition of any one of claims 1-6, wherein the polythiol composition is prepared from a reaction mixture comprising a dithiol, a dialdehyde, and a catalyst, and wherein the molar ratio of dithiol to dialdehyde is at least 4:

1.

8. 8. The polythiol composition of claim 7, wherein the molar ratio of dithiol to dialdehyde is from 6:1 to 12:

1.

9. 9. The polythiol composition of claim 7 or 8, wherein the dithiol comprises a polythiol according to formula (III), where n=2.

10. The polythiol composition of any one of claims 7 to 9, wherein the dialdehyde comprises glyoxal.

11. The polythiol composition of any one of claims 7 to 10, wherein the catalyst comprises lithium tetrafluoroborate.

12. A method for preparing the polythiol composition of any one of claims 1 to 11, comprising: a. preparing a reaction mixture comprising a dithiol, a dialdehyde, and a catalyst, wherein the molar ratio of dithiol to dialdehyde is at least 4:1; b. subjecting the reaction mixture to conditions sufficient to form the polythiol composition.

13. 13. The method of claim 12, wherein the molar ratio of dithiol to dialdehyde is at least 6:

1.

14. 14. The method of claim 12 or 13, wherein the molar ratio of dithiol to dialdehyde is from 6:1 to 12:

1.

15. The dithiol A polythiol according to formula (III): 【Chemistry 4】 The method of any one of claims 12 to 14, comprising a polythiol wherein n is 2 to 4.

16. The method of any one of claims 12 to 15, wherein the dialdehyde comprises glyoxal.

17. 17. The method of any one of claims 12 to 16, wherein the catalyst comprises lithium tetrafluoroborate.

18. 18. The method of any one of claims 12-17, wherein the conditions sufficient to form the polythiol composition comprise heating to a temperature of from 30 to 85°C for from 1 to 24 hours.

19. 1. A polymerizable composition comprising: a) the polythiol composition of any one of claims 1 to 11; b) an aliphatic polyisocyanate, wherein the equivalent ratio of isocyanate groups (—NCO) in said polyisocyanate b) to thiol (—SH) groups in said polythiol composition a) is from 1:0.9 to 1:1.

1.

20. 20. The polymerizable composition of claim 19, wherein the polyisocyanate b) comprises 4,4'-methylene-bis(cyclohexyl isocyanate), isophorone diisocyanate, an isomeric mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, and 1,6-hexamethylene diisocyanate, or mixtures thereof.

21. 21. An optical article formed from the polymerizable composition of claim 19 or 20.

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