CURABLE COMPOSITION AND OPTICAL MATERIAL COMPRISING CURED PRODUCT THEREOF

Abstract

A curable composition for forming a high refractive index optical material, the curable composition including an episulfide compound, a thiol compound and an aromatic ring compound containing two or more hydroxyl groups, and an optical material including a cured product of the curable composition.

Claims

1. A curable composition for forming a high refractive index optical material, the curable composition comprising: an episulfide compound; a thiol compound; and an aromatic ring compound containing two or more hydroxyl groups, wherein a weight ratio of the thiol compound and the aromatic ring compound containing two or more hydroxyl groups is 7:3 to 9:1.

2. The curable composition according to claim 1, wherein the weight ratio of the thiol compound and the aromatic ring compound containing two or more hydroxyl groups is 7:3 to 8:2.

3. The curable composition according to claim 1, wherein the episulfide compound comprises a compound represented by the following Chemical Formula 1. ##STR00010## wherein in Chemical Formula 1, R.sub.1 and R.sub.2 are each independently hydrogen or an alkyl having 1 to 10 carbon atoms, R.sub.3 and R.sub.4 are each independently a single bond or an alkylene having 1 to 10 carbon atoms, a is an integer of 0 to 4, and b is an integer of 0 to 6.

4. The curable composition according to claim 1, wherein the thiol compound comprises at least one selected from compounds represented by the following Chemical Formula 2 or 3. ##STR00011## wherein in Chemical Formula 2, R.sub.5 and R.sub.6 are each independently a single bond or alkylene having 1 to 10 carbon atoms, c is an integer of 0 to 4, d is an integer of 0 to 6, ##STR00012## wherein in Chemical Formula 3, ring A is a 5-membered or 6-membered aromatic hetero ring containing at least one of nitrogen (N) and sulfur (S) atoms, and e is an integer of 1 to 3.

5. The curable composition according to claim 1, wherein the aromatic ring compound containing two or more hydroxyl groups comprises at least one selected from compounds represented by the following Chemical Formulas 4 and 5. ##STR00013## wherein in Chemical Formula 4, R.sub.7 and R.sub.8 are each independently deuterium, halogen, cyano, nitrile, nitro, amino, an alkyl having 1 to 40 carbon atoms, an alkoxy having 1 to 40 carbon atoms, a cycloalkyl having 3 to 40 carbon atoms, an alkenyl having 1 to 40 carbon atoms, an aryl having 6 to 60 carbon atoms, or a heteroaryl having 1 to 40 carbon atoms containing at least one of O, N, Si and S, f and g are each independently an integer of 1 to 7, h and i are each independently an integer of 0 to 6, f+h is 7 or less, g+i is 7 or less, ##STR00014## wherein in Chemical Formula 5, Ar.sub.1 and A.sub.2 are each independently an aryl having 6 to 60 carbon atoms in which one or more hydroxyl groups are substituted. R.sub.9 and R.sub.10 are each independently deuterium, halogen, cyano, nitrile, nitro, amino, an alkyl of 1 to 40 carbon atoms, an alkoxy having 1 to 40 carbon atoms, a cycloalkyl having 3 to 40 carbon atoms, an alkenyl having 1 to 40 carbon atoms, an aryl having 6 to 60 carbon atoms, or a heteroaryl having 1 to 40 carbon atoms containing at least one of O, N, Si and S, and m and n are each independently an integer of 0 to 4.

6. The curable composition according to claim 1, wherein the episulfide compound comprises at least one selected from the group consisting of bis(β-epithiopropyl)sulfide, bis(β-epithiopropyl)disulfide, bis(β-epithiopropylthio)methane, 1,2-bis(β-epithiopropylthio)ethane, 1,3-bis(β-epithiopropylthio)propane, and 1,4-bis(β-epithiopropylthio)butane.

7. The curable composition according to claim 1, wherein the thiol compound comprises at least one selected from the group consisting of the following compounds: ##STR00015##

8. The curable composition according to claim 1, wherein the aromatic ring compound containing two or more hydroxyl groups comprises at least one selected from the following compounds: ##STR00016## ##STR00017##

9. The curable composition according to claim 1, wherein the curable composition further comprises a catalyst.

10. The curable composition according to claim 1, wherein the curable composition has a viscosity of 4000 cP or less after being held at a temperature of −5° C. for 12 hours.

11. An optical material comprising a cured product of a curable composition, the curable composition includes: an episulfide compound; a thiol compound; and an aromatic ring compound containing two or more hydroxyl groups, wherein a weight ratio of the thiol compound and the aromatic ring compound containing two or more hydroxyl groups is 7:3 to 9:1.

12. The optical material according to claim 11, wherein the optical material has a refractive index of 1.65 or more.

13. The optical material according to claim 11, wherein the optical material has a transmittance of 80% or more.

14. The optical material according to claim 11, wherein the optical material has a haze of 1% or less.

15. The optical material according to claim 11, wherein the optical material has a yellowness index (YI) of 1 to 30.

16. The optical material according to claim 11, wherein the optical material is for a lens of a wearable device.

Description

DETAILED DESCRIPTION

[0100] Hereinafter, the actions and effects of the invention will be described in more detail through specific examples of the invention. However, these examples are for illustrative purposes only, and the scope of rights of the invention is not determined thereby.

Example 1

[0101] 90 g of the following 70A as an episulfide compound, 9 g of the following 70B as a thiol compound, and 1 g of the following A1 as an aromatic ring compound containing two or more hydroxyl groups were vigorously mixed at 20° C. for 1 hour, and then the mixture was filtered using a glass filter having a pore size of 1 μm and then filtered once again using a PVDF filter having a pore size of 0.45 μm. Then, 0.5 g of N,N-dicyclohexylmethylamine was added as a catalyst and mixed for 5 minutes to prepare a curable composition.

[0102] A 1 mm thick slide glass was placed on both sides of a LCD glass having a size of 10 cm in width and length, and about 5 g of the above-mentioned mixed solution was applied to the center of the LCD glass, and then covered with another LCD glass to prepare a mold. This was put in an oven, and the curing reaction was performed at about 60° C. for about 10 hours and at about 90° C. for about 4 hours. After taken out of the oven, the LCD glass was removed to obtain a flat plastic specimen (optical material). The thickness of the plastic specimen was about 1 mm, and this thickness was measured using a Mitutoyo thickness gauge (Model: ID-C112XBS).

Examples 2 to 8 and Comparative Examples 1 to 3

[0103] A curable composition and a plastic specimen (optical material) as a cured product thereof were prepared in the same manner as in Example 1, except that the episulfide compound, the thiol compound and the aromatic ring compound containing two or more hydroxyl groups were used in the amount of the compounds shown in Table 1 below.

##STR00009##

TABLE-US-00001 TABLE 1 (unit: g) 70A 70B T1 T2 A1 A2 A3 Example 1 90 9 — — 1 — — Example 2 90 — 9 — 1 — — Example 3 90 1 8 — 1 — — Example 4 90 — — 9 1 — — Example 5 90 — 8 — 2 — — Example 6 90 — 7 — 3 — — Example 7 90 — 9 — — 1 — Example 8 90 — 9 — — — 1 Comparative 90 10 — — — — — Example 1 Comparative 90 — 10  — — — — Example 2 Comparative 90 — — 10  — — — Example 3 Comparative 90 9.3 0.7 Example 4 Comparative 90 9.5 0.5 Example 5 Comparative 90 6.7 3.3 Example 6 Comparative 90 6.5 3.5 Example 7

[0104] Evaluation of Physical Properties

[0105] 1. Evaluation of Optical Properties (Transmittance, Haze and Yellowness Index)

[0106] The transmittance, haze, and yellowness index of the sample were measured in the thickness direction of the cured product cured to a 1 mm standard thickness using COH-400 spectrometer manufactured by Nippon Denshoku Industries Co., Ltd., and the results are shown in Table 2 below.

[0107] 2. Measurement of Sulfur Atom Content

[0108] The content of sulfur atoms in the specimen was measured using an elemental analysis method, and the results are shown in Table 2 below.

[0109] 3. Measurement of Refractive Index

[0110] For the specimen, the refractive index value at a wavelength of 532 nm was measured using spectroscopic ellipsometry manufactured by Ellipso Technology, and the results are shown in Table 2 below.

[0111] 4. Measurement of Viscosity Before and After Long-Term Storage

[0112] Immediately after the preparation of the curable composition, the viscosity was measured at room temperature (25° C.) using Viscometer TV-22 viscometer manufactured by Toki Sangyo, and the results are shown in [Viscosity—Initial] of Table 2 below. Subsequently, the curable composition was maintained at a temperature of −5° C. for 12 hours, and then the viscosity was measured at room temperature (25° C.) in the same manner. The results are shown in [viscosity—after 12 hours] in Table 2 below.

TABLE-US-00002 TABLE 2 Trans- Yellow- Sulfur Re- Viscosity (cP) mit- ness atom frac- After tance Haze index content tive Ini- 12 (%) (%) (YI) (wt. %) index tial hours Example 1 87.4 0.3 3.2 54.15 1.723 100 3000 Example 2 87.5 0.3 3.4 54.30 1.741 100 2500 Example 3 87.3 0.3 3.3 54.28 1.740 100 2500 Example 4 86.8 0.3 21.5 53.42 1.738 100 4000 Example 5 87.6 0.3 3.7 53.66 1.739 100 500 Example 6 87.5 0.3 3.7 53.02 1.736 100 200 Example 7 87.7 0.3 2.4 54.30 1.730 100 2500 Example 8 87.5 0.3 3.0 54.30 1.734 100 3000 Comparative 88.0 0.3 3.4 54.77 1.705 100 Cured Example 1 Comparative 87.5 0.4 3.6 54.94 1.730 100 Cured Example 2 Comparative 86.7 0.3 26.3 53.96 1.732 100 cured Example 3 Comparative 87.3 0.3 6.7 54.33 1.702 100 5000 Example 4 Comparative 87.3 0.3 7.8 54.45 1.703 100 cured Example 5 Comparative 87.4 0.7 8.5 52.71 1.699 100 200 Example 6 Comparative 86.4 1.2 12.4 52.58 1.695 100 200 Example 7

[0113] Referring to Table 2, it can be seen that the specimen including the cured product according to Examples of the present disclosure exhibits very high transmittance, and has a relatively high refractive index while having low haze and yellowness index value. Also, it can be seen that the curable composition according to Examples of the present disclosure does not cure even after being stored for 12 hours, and thus, can be stored for a long period of time even if it is not used immediately after preparation. In particular, in the case of Examples 5 and 6, it was confirmed that the viscosity was as very low as 500 cP or less, even after storage for 12 hours.

[0114] On the other hand, it was confirmed that in the case of the curable compositions of Comparative Examples 1 to 3, curing occurred for all the curable compositions after storage for 12 hours, and long-term storage was not possible. Consequently, there is a problem that it is difficult to utilize the curable compositions of Comparative Examples 1 to 3 for lenses and the like, and occurrence of a striae phenomenon due to rapid curing may be predicted.

[0115] In addition, it was confirmed that in the case of the curable compositions of Comparative Examples 4 and 5, viscosity increased or curing occurred after storage for 12 hours to such an extent that molding into a high refractive lens and the like was impossible. Consequently, there is a problem that it is difficult to utilize the curable compositions of Comparative Examples 4 and 5 for a lens and the like, and occurrence of a striae phenomenon due to rapid curing may be predicted.

[0116] Furthermore, it was confirmed that in the case of the curable compositions of Comparative Examples 6 and 7, the haze and the yellowness index of the specimen including the cured product were high and the refractive index was as low as less than 1.70, and thus the curable compositions were not suitable for use as a composition for forming a high refractive index lens for a wearable device.