A polythiol composition and application

Abstract

The present invention relates to optical materials such as plastic lenses, prisms, and filters, and more particularly to a polythiol composition and its application. By adjusting the mass content of a thiol compound represented by formula (1) in a polythiol composition containing 2,3-dithio(2-mercapto)-1-propanethiol as a main component, the problem of a yellowish base color of the material due to excessively rapid cooling can be solved, ultimately regulating the base color of an optical material prepared from the polythiol composition.

Description

Technical Field

[0001] The present invention relates to optical materials such as plastic lenses, prisms, filters, and in particular to a polythiol composition and application thereof. Background Art

[0002] Transparent plastic materials, with their advantages of light weight, strong toughness, and easy dyeing, have been frequently used in the preparation of various optical materials in recent years. Applications in eyewear and lenses require high transparency, low yellowing, high heat resistance, high strength, and a high refractive index and Abbe number. A high refractive index allows for thinner lens walls, while a high Abbe number reduces chromatic aberration.

[0003] Polythiourethane optical resin materials with the above excellent properties have been an important development direction in recent years. This type of resin material is mainly prepared using polythiol compounds and isocyanates as raw materials.

[0004] However, optical resin materials prepared from 2,3-dithio(2-mercapto)-1-propanethiol (Formula (2)) and isocyanate sometimes have a yellowish base color. Here, the base color refers to the color of the lens prepared without adding pigments. We conducted a comprehensive investigation and in-depth analysis of this issue and found that the curing and cooling rate of the resin material is one of the factors affecting the base color of the material. Studies have shown that the faster the curing and cooling rate, the yellower the base color of the material. In the production process of optical materials, the following problems often occur: the material is taken out of the 80°C oven and molded at room temperature. At this time, the material temperature quickly cools from about 80°C to about 30°C, which ultimately affects the base color of the material. At the same time, the different room temperatures in summer and winter and the different temperatures when the material is taken out of the oven cause the base color of the material to be unstable. Studying how to improve the stability of the base color of the material and reduce the impact of the curing and cooling rate on the base color is the key to solving the problem. Summary of the Invention

[0005] In response to the above-mentioned prior art problems, the inventors of the present application have conducted repeated research and discovered that the above-mentioned problems can be solved by using a thiol compound represented by the following formula (1). Therefore, the present application proposes a polythiol composition and its application. By adjusting the mass content of the thiol compound represented by formula (1) in the polythiol composition mainly composed of 2,3-dithio(2-mercapto)-1-propanethiol, the problem of the base color of the material being yellowish due to excessively fast cooling rate can be solved, and ultimately the base color of the optical material prepared from the polythiol composition can be controlled.

[0006] In order to achieve the above technical objectives, the technical solution of the present invention includes:

[0007] First, the inventors studied and synthesized a thiol compound for the first time, whose structure is shown in formula (1):

[0008]

[0009] The inventors further studied the application of the present invention in a polythiol composition, thereby further providing a polythiol composition comprising a thiol compound of formula (1) and a polythiol compound of formula (2).

[0010]

[0011] Preferably, the mass content of the thiol compound of formula (1) in the polythiol composition is 0.001-1.0%.

[0012] More preferably, the mass content of the thiol compound of formula (1) in the polythiol composition is 0.02-0.5%.

[0013] The present invention further provides a composition for an optical material based on the above-mentioned polythiol composition, which comprises the above-mentioned polythiol composition and polyisocyanate.

[0014] In the above-mentioned composition for optical materials, the polyisocyanate can be conventionally used, and can be specifically selected from tetramethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, 4,4'-diisocyanate dicyclohexylmethane, isophorone diisocyanate, norbornane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethyl-m-xylylene diisocyanate, dipropyl disulfide, diethyl disulfide, 2,5-diisocyanatomethylthiophene, 2,5-diisocyanatomethyl The thiocyanate may be selected from the group consisting of 1,4-dithiane, 2,5-diisocyanate-1,4-dithiane, thiodihexyl diisocyanate, thiodipropyl diisocyanate, bis(isocyanatomethyl)adamantane, bis(isocyanatomethyl)tetrahydrothiophene, 2,6-bis(isocyanatomethyl)naphthalene, 1,5-naphthalene diisocyanate, diethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine triisocyanate, toluene diisocyanate, o-tolidine diisocyanate, diphenylmethane diisocyanate, diphenylether diisocyanate, triphenylmethane triisocyanate, etc. Preferably, the thiocyanate may be selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, m-xylylene diisocyanate, and hydrogenated m-xylylene diisocyanate. Most preferably, it can be selected from hydrogenated meta-xylylenediisocyanate, norbornane diisocyanate, and meta-xylylenediisocyanate.

[0015] The optical material composition may also contain other polythiol compounds.

[0016] The other polythiol compounds can be conventional polythiol compounds, specifically 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, methanedithiol, methanetrithiol, bis(2-mercaptoethyl)ether, tetra(mercaptomethyl)methane, 1,2-dimercaptopropane, 1,3-dimercaptopropane, 1,4-dimercaptobutane, 1,6-dimercaptohexane, 2,2-dimercaptopropane, 1,2-bis(2-mercaptoethoxy)ethane, 1,2-bis(2-mercaptoethyl)ether thio)ethane, 2,3-dimercapto-1-propanol, 1,2-dimercaptoethane, 1,3-dimercapto-2-propanol, 2-mercaptomethyl-1,3-dimercaptopropane, 2-mercaptomethyl-1,4-dimercaptobutane, 1,2,3-trimercaptopropane, 2-(2-mercaptoethylthio)-1,3-dimercaptopropane, 2,4-dimercaptomethyl-1,5-dimercapto-3-thiapentane, bis(2-mercaptoethyl) sulfide, ethylene glycol bis(3-mercaptopropionate), diethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(2-mercaptoacetate), 1,4-butanediol bis(2-mercaptoacetate), trimethylolpropane trimercaptopropionate, pentaerythritol tetramercaptoacetate, diethylene glycol bis( 3-Mercaptopropionate), pentaerythritol tetramercaptopropionate, 1,2-dimercaptocyclohexane, 1,1,1-tris(mercaptomethyl)propane, 1,4-butanediol bis(3-mercaptopropionate), 1,3-dimercaptocyclohexane, trimethylolpropane trimercaptoacetate, 1,4-dimercaptocyclohexane, 1,3-bis(mercaptomethyl)cyclohexane, 1,4-bis(mercaptomethyl)cyclohexane, bis(4-mercaptophenyl)sulfone, 2,5-dimercaptomethyl-1,4-dithiane, 2,5-bis(2-mercaptoethylthiomethyl)-1,4-dithiane, 2,5-dimercaptomethyl-1-thiane, 2,5-dimercaptoethyl-1-thiane, 2,5-dimercaptomethylthiophene, bis(4-mercaptophenyl)sulfide, 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,3-bis(mercaptomethyl)benzene, 2,5-dimercaptomethyl-1,4-dithiane, 1,4-bis(mercaptomethyl)benzene, 2,2'-dimercaptobiphenyl, bis(4-mercaptophenyl)methane, 2,2-bis(4-mercaptophenyl)propane, 4,4'-dimercaptobiphenyl, bis(4-mercaptophenyl)ether, bis(4-mercaptomethylphenyl)methane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 2,2-bis(4-mercaptomethylphenyl)propane, bis(4-mercaptomethylphenyl)ether, bis(4-mercaptomethylphenyl)sulfide, 2,5-dimercapto-1,3,4-thiadiazole, 3,4-thiophenedithiol, etc.

[0017] A method for preparing an optical material comprises the following steps: adding a catalyst in an amount of 0.001% to 0.2% of the total mass of the optical material composition to the optical material composition, and performing polymerization and curing.

[0018] The catalyst is selected from dibutyltin dilaurate, dibutyltin dichloride, dibutyltin oxide, and stannous octoate. Preferably, the catalyst is selected from dibutyltin dilaurate and dibutyltin dichloride.

[0019] The amount of the catalyst added varies depending on the components of the optical material composition. Based on 100% by mass of the optical material composition, the amount of the catalyst added is 0.005-0.2%, preferably 0.01-0.1%, and more preferably 0.01-0.05%.

[0020] If the catalyst addition amount is less than 0.005%, the polymerization may be incomplete, resulting in poor mechanical properties of the optical material. If the catalyst addition amount is greater than 0.2%, the polymerization rate may be too fast, resulting in a higher color tone of the optical material.

[0021] In addition to adding a catalyst in the preparation method of the optical material, a release agent, an ultraviolet absorber, a toner, a mold release agent, etc. can be added as needed to further improve the performance of the optical material.

[0022] The present invention further provides a method for preparing a thiol compound of formula (1). The thiol compound of formula (1) used in the present invention can be prepared by this method or by other means or methods. The specific preparation method is as follows:

[0023] Lucas reagent is used to convert a thiol group in 2,3-dithio(2-mercapto)-1-propanethiol (a polythiol compound of formula (2)) into a chloro group, and nucleophilic substitution occurs under alkaline conditions to generate a cyclic thioether, which is then adjusted to a acidic state and purified to obtain a thiol compound shown in formula (1).

[0024] In summary, the present invention prepares a thiol compound (Formula (1)), which is mixed with 2,3-dithio(2-mercapto)-1-propanethiol to prepare a polythiol composition, which can be further used to prepare an optical material. The present invention limits the mass content of the thiol compound of Formula (1). Compared with technical solutions that do not contain the thiol compound of Formula (1) or whose content exceeds the scope of the present invention, the performance of the prepared optical material can be effectively improved, especially the light transmittance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a mass spectrometry analysis of the thiol compound synthesized in Example 1 of the present application;

[0026] Figure 2This is the NMR spectrum of the thiol compound synthesized in Example 1 of the present application. DETAILED DESCRIPTION

[0027] The invention will be further described below with reference to specific embodiments, which may enable those skilled in the art to further understand the invention. However, this is not intended to limit the invention, and all technologies based on the principles of the invention fall within the scope of the invention.

[0028] In the following examples and comparative examples:

[0029] 1. 1 H-NMR determination:

[0030] 2. The measurements were performed using a Bruker 500 MHz liquid nuclear magnetic resonance spectrometer (AVANCE 500).

[0031] 3. Mass spectrometry analysis:

[0032] The determination was performed using an Agilent 6520B-QTOF liquid chromatography-mass spectrometer with EI ionization.

[0033] 3. Primary color characterization method:

[0034] A semi-automatic mold-closing machine was used to combine two sheets of 80mm diameter flat glass with adhesive tape to create a 2mm thick mold. An optical material composition, containing a catalyst and a release agent, was injected into the mold and subjected to programmed temperature curing. After curing, the temperature was lowered and the material was demolded to obtain the optical material. A colorimeter was used to measure the material's b value. A higher b value indicates a yellower color, while a lower b value indicates a lighter color.

[0035] 4. Curing temperature program:

[0036] Maintain at 30°C for 180 minutes, raise the temperature to 45°C after 120 minutes, raise the temperature to 50°C after 90 minutes, raise the temperature to 60°C after 120 minutes, raise the temperature to 120°C after 240 minutes, maintain at 120°C for 240 minutes, and then cool to 80°C after 120 minutes.

[0037] Example 1

[0038] Preparation of thiol compound of formula (1):

[0039] To prepare Lucas reagent, heat and melt 68g of anhydrous zinc chloride in an evaporating dish, cool in a desiccator, crush, and dissolve in 46g of 36% hydrochloric acid. The dissolution process releases heat, and cool with cold water.

[0040] 130 g of the polythiol compound represented by formula (2) was added to a four-necked flask equipped with a thermometer and a stirrer, and the prepared Lucas reagent was added. The mixture was heated to 50° C. and reacted for 2 h to obtain a chlorinated product. The chlorinated product in the lower layer was transferred to another four-necked flask using a separatory funnel. 62.5 g of a 32% aqueous sodium hydroxide solution was added, the temperature was raised to 40° C., and the mixture was stirred for reaction for 3 h. The mixture was transferred to a separatory funnel, and the lower layer product was cut into a single-necked bottle. Hydrochloric acid was added to adjust the pH to 5-6, and 120 g of water was added for pickling. The pickled product was dehydrated under reduced pressure.

[0041] The qualitative analysis results of the obtained product are as follows:

[0042] like Figure 1 and Figure 2 As shown, nuclear magnetic resonance: 1H-NMR spectrum (CDCl3): δ = 1.40 (1H), 2.6-3.2 (13H); mass spectrum (EI): analytical value: 226, calculated value: 226. The structure of the obtained product was confirmed to be as shown in formula (1).

[0043] Example 2

[0044] The thiol compound of formula (1) and the polythiol compound of formula (2) are mixed in different proportions to obtain polythiol compositions of different compositions.

[0045] The mass contents of the thiol compound of formula (1) in the polythiol composition are 0.001%, 0.01%, 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 2.0%, respectively.

[0046] Examples 3-11 and Comparative Examples 1-2

[0047] Comparative Example 1 The specific scheme is as follows: 52.0 parts by mass of xylylene diisocyanate, 0.01 parts by mass of catalyst (dibutyltin dichloride), and 0.08 parts by mass of release agent (polyphosphate) are added to a flask, and stirred and dissolved at 10-15°C; 48.0 parts by mass of 2,3-dithio(2-mercapto)-1-propanethiol are added and stirred evenly. A vacuum pump is used for degassing, the pressure is controlled below 350Pa, and the degassing time is 0.5-1.0 hours to prepare a mixed solution, which is poured into a mold with a diameter of 80mm and a center thickness of 2.0mm. The solution is placed in an oven for programmed temperature curing. The oven temperature is reduced to 80°C, the mold is removed and opened, and the material is naturally cooled at room temperature of 25°C for 1 hour. The b value is detected using a colorimeter.

[0048] The technical solutions of Examples 3-11 and Comparative Example 2 are as follows: the polythiol compositions with different contents of the thiol compound of formula (1) prepared in Example 2 are used to replace the 2,3-dithio(2-mercapto)-1-propanethiol in Comparative Example 1, and the other operations are the same as those in Comparative Example 1. The specific differences between the various Examples and Comparative Examples and the b values of the obtained optical materials are shown in the following table:

[0049]

[0050] Examples 12-20 and Comparative Examples 3-4

[0051] Comparative Example 3 Specific scheme: Add 49.8 parts by mass of hydrogenated xylylene diisocyanate, 0.10 parts by mass of catalyst (dibutyltin dichloride), and 0.10 parts by mass of release agent (polyphosphate) into a flask, and stir and dissolve at 10-20°C; add 30.2 parts by mass of 2,3-dithio(2-mercapto)-1-propanethiol and 20.0 parts by mass of pentaerythritol tetramercaptopropionate, and stir evenly. Degas using a vacuum pump, control the pressure below 350Pa, and degas for 0.5-1.0 hours to prepare a mixed solution. The solution is then poured into a mold with a diameter of 80mm and a center thickness of 2.0mm, placed in an oven for programmed temperature curing, and the oven temperature is reduced to 80°C. The mold is removed and opened, and the material is naturally cooled at room temperature of 25°C for 1 hour. The b value is measured using a colorimeter.

[0052] The technical solutions of Examples 12-20 and Comparative Example 4 are as follows: the polythiol compositions containing different amounts of the thiol compound of formula (1) prepared in Example 2 are used to replace the 2,3-dithio(2-mercapto)-1-propanethiol in Comparative Example 3, and the other operations are the same as Comparative Example 3. The specific differences between the various Examples and Comparative Examples and the b-value results of the obtained optical materials are shown in the following table:

[0053]

[0054]

[0055] Example 21

[0056] 22.8 parts by mass of hexamethylene diisocyanate, 10.0 parts by mass of isophorone diisocyanate, 16.0 parts by mass of hydrogenated xylylene diisocyanate, 0.15 parts by mass of a catalyst (dibutyltin dichloride), and 0.10 parts by mass of a release agent (polyphosphate) were added to a flask and stirred to dissolve at 10-20°C. 33.0 parts by mass of the polythiol composition containing 0.1% of the thiol compound of formula (1) in Example 2 and 18.2 parts by mass of pentaerythritol tetramercaptopropionate were added and stirred uniformly. Degassing was performed using a vacuum pump with the pressure controlled below 350 Pa for 0.5-1.0 hours to prepare a mixed solution. The solution was then poured into a mold with a diameter of 80 mm and a center thickness of 2.0 mm and placed in an oven for programmed temperature curing. The oven temperature was lowered to 80°C, the mold was removed and opened, and the material was naturally cooled at room temperature of 25°C for 1 hour. The b value was measured using a colorimeter and was 0.27.

[0057] Example 22

[0058] 49.6 parts by mass of norbornane diisocyanate, 0.03 parts by mass of a catalyst (dibutyltin dichloride), and 0.75 parts by mass of a release agent (polyphosphate) were added to a flask and stirred to dissolve at 10-20°C. 25.5 parts by mass of the polythiol composition containing 0.1% of the thiol compound of formula (1) in Example 2 and 23.9 parts by mass of pentaerythritol tetramercaptopropionate were added and stirred uniformly. Degassing was performed using a vacuum pump with the pressure controlled below 350 Pa for 0.5-1.0 hours to prepare a mixed solution. The solution was then poured into a mold with a diameter of 80 mm and a center thickness of 2.0 mm and placed in an oven for programmed temperature curing. The oven temperature was lowered to 80°C, the mold was removed and opened, and the material was naturally cooled at room temperature of 25°C for 1 hour. The b value was detected by a colorimeter to be 0.34.

[0059] The above examples and corresponding proportional data fully demonstrate that the polythiol composition of the present invention has significant technical effects compared to the prior art in its application. It can significantly improve the performance of the prepared optical material, especially reduce the b value of the optical material and improve the base color of the material.

Claims

1. A thiol compound, the structure of which is shown in formula (1): （1）。 2. A polythiol composition, characterized in that The composition comprises a thiol compound of formula (1) and a polythiol compound of formula (2), wherein the mass content of the thiol compound of formula (1) in the polythiol composition is 0.001-1.0%; （1） ； （2）。 3. The polythiol composition according to claim 2, characterized in that The mass content of the thiol compound of formula (1) in the polythiol composition is 0.02-0.5%.

4. A composition for an optical material, characterized in that The method comprises the polythiol composition according to claim 2 and polyisocyanate.

5. The optical material composition according to claim 4, wherein The polyisocyanate is selected from tetramethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, 4,4'-diisocyanate dicyclohexylmethane, isophorone diisocyanate, norbornane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethyl-m-xylylene diisocyanate, dipropyl disulfide, diethyl disulfide, 2,5-diisocyanatomethylthiophene, 2,5-diisocyanatomethyl-1,4-dithiane, 2, 5-Diisocyanate-1,4-dithiane, dihexylthiodiisocyanate, dipropylthiodiisocyanate, bis(isocyanatomethyl)adamantane, bis(isocyanatomethyl)tetrahydrothiophene, 2,6-bis(isocyanatomethyl)naphthalene, 1,5-naphthalene diisocyanate, diethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine triisocyanate, toluene diisocyanate, o-tolidine diisocyanate, diphenylmethane diisocyanate, diphenyl ether diisocyanate, triphenylmethane triisocyanate.

6. The optical material composition according to claim 4, wherein The composition for optical materials comprises other polythiol compounds, and the other polythiol compounds are selected from 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, methanedithiol, methanetrithiol, bis(2-mercaptoethyl) ether, tetrakis(mercaptomethyl)methane, 1,2-dimercaptopropane, 1,3-dimercaptopropane, 1,4-dimercaptobutane, 1,6-dimercaptohexane, 2,2-dimercaptopropane, 1,2-bis(2-mercaptoethoxy)ethane, 1,2-bis(2-mercaptoethyl)ether, Mercaptoethylthio)ethane, 2,3-dimercapto-1-propanol, 1,2-dimercaptoethane, 1,3-dimercapto-2-propanol, 2-mercaptomethyl-1,3-dimercaptopropane, 2-mercaptomethyl-1,4-dimercaptobutane, 1,2,3-trimercaptopropane, 2-(2-mercaptoethylthio)-1,3-dimercaptopropane, 2,4-dimercaptomethyl-1,5-dimercapto-3-thiapentane, bis(2-mercaptoethyl) sulfide, ethylene glycol bis(3-mercaptopropionate), diethylene glycol bis(2-mercaptoacetate), ethylene glycol bis(2-mercaptoacetate), 1,4-butanediol bis(2-mercaptoacetate), trimethylolpropane trimercaptopropionate, pentaerythritol tetramercaptoacetate, diethylene glycol 1,2-Dimercaptocyclohexane, 1,1,1-Tris(mercaptomethyl)propane, 1,4-Butanediol bis(3-mercaptopropionate), 1,3-Dimercaptocyclohexane, trimethylolpropane trimercaptoacetate, 1,4-Dimercaptocyclohexane, 1,3-Bis(mercaptomethyl)cyclohexane, 1,4-Bis(mercaptomethyl)cyclohexane, bis(4-mercaptophenyl)sulfone, 2,5-Dimercaptomethyl-1,4-dithiane, 2,5-Bis(2-mercaptoethylthiomethyl)-1,4-dithiane, 2,5-Dimercaptomethyl-1-thiane, 2,5-Dimercaptoethyl-1-thiane, 2,5-Dimercaptomethylthiophene, bis(4-mercaptophenyl)sulfone ether, 1,2-dimercaptobenzene, 1,3-dimercaptobenzene, 1,4-dimercaptobenzene, 1,3-bis(mercaptomethyl)benzene, 2,5-dimercaptomethyl-1,4-dithiane, 1,4-bis(mercaptomethyl)benzene, 2,2'-dimercaptobiphenyl, bis(4-mercaptophenyl)methane, 2,2-bis(4-mercaptophenyl)propane, 4,4'-dimercaptobiphenyl, bis(4-mercaptophenyl)ether, bis(4-mercaptomethylphenyl)methane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 2,2-bis(4-mercaptomethylphenyl)propane, bis(4-mercaptomethylphenyl)ether, bis(4-mercaptomethylphenyl)sulfide, 2,5-dimercapto-1,3,4-thiadiazole, 3,4-thiophenedithiol.

7. A method for preparing an optical material, characterized in that: The process comprises: adding a catalyst in an amount of 0.001% to 0.2% by weight of the total mass of the optical material composition to the optical material composition according to any one of claims 4 to 6, and performing polymerization and curing.

8. The method for preparing an optical material according to claim 7, wherein: The catalyst is selected from dibutyltin dilaurate, dibutyltin dichloride, dibutyltin oxide, and stannous octoate; based on 100% by mass of the optical material composition, the added amount of the catalyst is 0.005-0.2%.

9. The method for preparing an optical material according to claim 7, wherein: Other additives may be added as needed, including release agents, UV absorbers, toners, and mold release agents.

10. The method for preparing the thiol compound according to claim 1, characterized in that: The specific preparation method is as follows: Lucas reagent is used to convert a thiol group in 2,3-dithio(2-mercapto)-1-propanethiol into a chloro group, and nucleophilic substitution occurs under alkaline conditions to generate a cyclic thioether, and then the acidity is adjusted and purified to obtain the thiol compound shown in formula (1).

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