阅读说明：本技术 可固化组合物和包含其固化产物的光学材料 (Curable composition and optical material comprising cured product thereof ) 是由 崔熙正 金宪 金在永 于 2020-05-21 设计创作，主要内容包括：本公开内容涉及可固化组合物和包含其固化产物的光学材料,并且更特别地涉及以特定的重量比包含具有特定结构的环硫化物化合物和含有两个或更多个羟基的芳族环化合物的可固化组合物,以及包含其固化产物的光学材料。(The present disclosure relates to a curable composition and an optical material including a cured product thereof, and more particularly to a curable composition including an episulfide compound having a specific structure and an aromatic ring compound having two or more hydroxyl groups in a specific weight ratio, and an optical material including a cured product thereof.)

1. A curable composition for forming a high refractive index optical material, the curable composition comprising: an episulfide compound represented by the following chemical formula 1; and an aromatic ring compound having two or more hydroxyl groups represented by the following chemical formula 2 or 3, wherein the weight ratio of the episulfide compound to the aromatic ring compound having two or more hydroxyl groups is 7:3 to 9:1,

[ chemical formula 1]

In the chemical formula 1, the first and second organic solvents,

R₁and R₂Each independently hydrogen or alkyl having 1 to 10 carbon atoms,

R₃and R₄Each independently a single bond or an alkylene group having 1 to 10 carbon atoms,

a is an integer of 0 to 4, and

b is an integer of 0 to 6,

[ chemical formula 2]

In the chemical formula 2,

R₅and R₆Each independently is deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 1 to 40 carbon atoms, cycloalkyl having 3 to 40 carbon atoms, alkenyl having 1 to 40 carbon atoms, aryl having 6 to 60 carbon atoms, or a salt comprising O, N,A heteroaryl group having 1 to 40 carbon atoms of at least one of Si and S,

c and d are each independently an integer of 1 to 7,

e and f are each independently an integer from 0 to 6,

c + e is 7 or less, d + f is 7 or less,

[ chemical formula 3]

In the chemical formula 3, the first and second organic solvents,

Ar₁and Ar₂Each independently an aryl group having 6 to 60 carbon atoms in which one or more hydroxyl groups are substituted,

R₇and R₈Each independently is deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 1 to 40 carbon atoms, cycloalkyl having 3 to 40 carbon atoms, alkenyl having 1 to 40 carbon atoms, aryl having 6 to 60 carbon atoms, or 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.

2. The curable composition of claim 1,

wherein the weight ratio of the thiol compound and the aromatic ring compound having two or more hydroxyl groups is 8:2 to 9: 1.

3. The curable composition of claim 1,

the episulfide compound includes 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.

4. The curable composition of claim 1, wherein

The aromatic ring compound containing two or more hydroxyl groups includes at least one selected from the group consisting of:

5. the curable composition of claim 1, wherein

The curable composition further comprises a catalyst.

6. An optical material comprising:

a cured product of an episulfide compound represented by the following chemical formula 1 and an aromatic ring compound containing two or more hydroxyl groups represented by the following chemical formula 2 or 3,

wherein the episulfide compound and the aromatic ring compound having two or more hydroxyl groups are contained in a weight ratio of 7:3 to 9:1,

[ chemical formula 1]

In the chemical formula 1, the first and second organic solvents,

R₁and R₂Each independently hydrogen or alkyl having 1 to 10 carbon atoms,

R₃and R₄Each independently a single bond or an alkylene group having 1 to 10 carbon atoms,

a is an integer of 0 to 4, and

b is an integer of 0 to 6,

[ chemical formula 2]

In the chemical formula 2,

R₅and R₆Each independently being deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 1 to 40 carbon atoms, cycloalkyl having 3 to 40 carbon atoms, alkenyl having 1 to 40 carbon atoms, aryl having 6 to 60 carbon atoms, or heteroaryl having 1 to 40 carbon atoms containing at least one of O, N, Si and S,

c and d are each independently an integer of 1 to 7,

e and f are each independently an integer from 0 to 6,

c + e is 7 or less, d + f is 7 or less,

[ chemical formula 3]

In the chemical formula 3, the first and second organic solvents,

Ar₁and Ar₂Each independently an aryl group having 6 to 60 carbon atoms in which one or more hydroxyl groups are substituted,

R₇and R₈Each independently is deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 1 to 40 carbon atoms, cycloalkyl having 3 to 40 carbon atoms, alkenyl having 1 to 40 carbon atoms, aryl having 6 to 60 carbon atoms, or 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.

7. The optical material of claim 6, wherein

The refractive index of the optical material is 1.65 or more.

8. The optical material of claim 6, wherein

The optical material has a glass transition temperature (Tg) of 80 ℃ or higher.

9. The optical material of claim 6, wherein

The optical material has a transmittance of 80% or more.

10. The optical material of claim 6, wherein

The optical material has a haze of 1% or less.

11. The optical material of claim 6, wherein

The Yellowness Index (YI) of the optical material is 1 to 10.

12. The optical material of claim 6, wherein

The optical material is used for a lens of a wearable device.

Technical Field

Cross Reference to Related Applications

This application claims the benefit of korean patent application No. 10-2019-0061428, filed 24.5.2019 to the korean intellectual property office, the disclosure of which is incorporated herein by reference in its entirety.

The present disclosure relates to a curable composition for forming a high refractive index optical material and an optical material comprising a cured product thereof.

Background

Recently, devices for providing 3D images to users by using virtual reality devices and augmented reality devices have been developed. A virtual reality device or augmented reality device may form a diffractive light guiding pattern on a lens such as ordinary eyeglasses to make a desired image visible to a user.

Generally, a lens for a virtual reality device or an augmented reality device uses glass having a high refractive index. Glass may have high refractive index, light transmittance, flatness, strength, and scratch resistance effect, but may cause fatal damage to the eyeball of a user when broken. In addition, glass is high in density and heavy, and therefore is uncomfortable to wear for a long time.

On the other hand, in the case of high-refractive plastic, it is lighter than a glass lens, and thus comfortable to wear, is not easily broken, is relatively safer than a glass lens even if it is broken, and can realize various colors. However, there is a problem that it is difficult to achieve a high refractive index and a high Abbe number (Abbe number) as compared with a glass lens. In addition, there is a problem that the glass transition temperature is as low as less than 80 ℃. Therefore, research is required to improve these problems.

In addition, since the curing solution for forming a high refractive plastic includes a curing agent and/or a catalyst, it shows a tendency that a curing reaction rate increases and viscosity rapidly increases. For this reason, the solidifying solution must be consumed within a short time after the solidifying solution is prepared, and there is a problem in that it is difficult to further store the remaining solution.

Disclosure of Invention

Technical problem

It is an object of the present disclosure to provide a curable composition for forming a high refractive index optical material, which can be stored for a long time and can prevent a streaking phenomenon caused by rapid curing.

Another object of the present disclosure is to provide an optical material that is not only lighter than glass or tempered glass used for conventional lenses, can realize various colors while having excellent strength and hardness, and can realize a high glass transition temperature while realizing a high refractive index.

Technical scheme

In one aspect, a curable composition is provided, the curable composition comprising: an episulfide compound represented by the following chemical formula 1; and an aromatic ring compound having two or more hydroxyl groups represented by the following chemical formula 2 or 3, wherein the weight ratio of the episulfide compound to the aromatic ring compound having two or more hydroxyl groups is 7:3 to 9: 1.

[ chemical formula 1]

In the chemical formula 1, the first and second,

R₁and R₂Each independently hydrogen or alkyl having 1 to 10 carbon atoms,

R₃and R₄Each independently a single bond or an alkylene group having 1 to 10 carbon atoms,

a is an integer of 0 to 4, and

b may be an integer of 0 to 6,

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

R₅and R₆Each independently is deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 1 to 40 carbon atoms, cycloalkyl having 3 to 40 carbon atoms, alkenyl having 1 to 40 carbon atoms, aryl having 6 to 60 carbon atoms, orA heteroaryl group having 1 to 40 carbon atoms comprising at least one of O, N, Si and S,

c and d are each independently an integer of 1 to 7,

e and f are each independently an integer from 0 to 6,

c + e is 7 or less, d + f is 7 or less,

[ chemical formula 3]

In the chemical formula 3, the first and second,

Ar₁and Ar₂Each independently an aryl group having 6 to 60 carbon atoms in which one or more hydroxyl groups are substituted,

R₇and R₈Each independently is deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 1 to 40 carbon atoms, cycloalkyl having 3 to 40 carbon atoms, alkenyl having 1 to 40 carbon atoms, aryl having 6 to 60 carbon atoms, or 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.

In another aspect, there is provided an optical material comprising a cured product of an episulfide compound represented by chemical formula 1 and an aromatic ring compound containing two or more hydroxyl groups represented by chemical formula 2 or 3, wherein the episulfide compound and the aromatic ring compound containing two or more hydroxyl groups are included in a weight ratio of 7:3 to 9: 1.

Hereinafter, a curable composition and an optical material including a cured product thereof according to specific embodiments of the present disclosure will be described in more detail.

The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the invention. The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

It will be understood that the terms "comprises," "comprising," "includes" and "including," when used herein, are intended to specify the presence of stated features, regions, integers, steps, actions, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, actions, elements, components, and/or groups thereof.

As used herein, the term "episulfide compound" refers to a compound comprising one or more episulfide compounds, wherein an episulfide refers to a compound in which the oxygen (O) atom of an epoxide is replaced by a sulfur (S) atom.

As used herein, "curable" is meant to include both thermally and photocurable, and "curable composition" is meant to refer to thermally curable and/or photocurable compositions.

As used herein, high refractive index means about 1.6 or greater at a wavelength from 350nm to 800nm or 532 nm.

According to one embodiment of the present disclosure, there is provided a curable composition comprising: an episulfide compound represented by chemical formula 1; and an aromatic ring compound having two or more hydroxyl groups represented by chemical formula 2 or 3, wherein the weight ratio of the episulfide compound to the aromatic ring compound having two or more hydroxyl groups is 7:3 to 9: 1.

In general, it has been determined that the refractive index of the optical material as a cured product of the curing solution is higher as the content of the sulfur atom contained in the curing solution is higher, and therefore, it is permissible to contain a thiol compound or the like as the curing agent in the curing solution. However, in the case of using a curing solution of a thiol compound, a curing reaction proceeds immediately after mixing, and viscosity rapidly increases, and a streaking phenomenon occurs due to rapid curing. Further, the glass transition temperature is as low as less than 80 ℃, which causes a problem of deterioration in physical properties and the like.

However, the present inventors have found that, when an aromatic ring compound having two or more hydroxyl groups with a specific structure is used in place of a thiol compound, and the weight ratio of the episulfide compound having a specific chemical structure to the aromatic ring compound having two or more hydroxyl groups is controlled within a specific range, a rapid curing reaction does not occur immediately after mixing, so long-term storage is possible and a streaking phenomenon caused by rapid curing does not occur, and it was found that an optical material which is a cured product of such a curable composition has a very high glass transition temperature of 80 ℃ or more while exhibiting a high refractive index and excellent optical characteristics, and thus is excellent in mechanical properties, so that an optical material that can replace glass or plastic materials used in the past can be provided, thereby completing the present disclosure.

Accordingly, the curable composition and the optical material comprising the cured product thereof can be effectively applied to products or substitutes for existing glass or optical glass, or to commercial products such as display substrates, display protective films, touch panels, lenses for wearable devices.

Specifically, the weight ratio of the episulfide compound and the aromatic ring compound having two or more hydroxyl groups contained in the curable composition according to one embodiment may be 7:3 to 9:1, 7.5:2.5 to 9:1, or 8:2 to 9: 1. When the weight ratio of the episulfide compound and the aromatic ring compound having two or more hydroxyl groups is less than 7:3, the aromatic ring compound having two or more hydroxyl groups may not be sufficiently dissolved or precipitated in the curable composition, and therefore, it is difficult to form a cured product, or even if a cured product is formed, there is a problem that optical characteristics and mechanical characteristics are deteriorated. On the other hand, when the weight ratio exceeds 9:1, uncured by-products and the like are generated due to a relative increase in the content of the episulfide compound, which causes problems that the glass transition temperature of the optical material as a cured product is lowered and the Yellowness Index (YI) is increased.

The episulfide compound contained in the curable composition may include a compound represented by the following chemical formula 1.

[ chemical formula 1]

In the chemical formula 1, the first and second,

R₁and R₂Each independently hydrogen or alkyl having 1 to 10 carbon atoms,

R₃and R₄Each independently a single bond or an alkylene group having 1 to 10 carbon atoms,

a is an integer of 0 to 4, and

b may be an integer of 0 to 6.

Due to the above-described specific chemical structure, the episulfide compound can contain a high content of sulfur (S) atoms having a large atomic refractive index in the molecule, and the refractive index of the cured product can be increased by such a high content of sulfur atoms.

In addition, the episulfide compound can be cured by ring-opening polymerization, and an alkylene sulfide (alkylene sulfide) group formed by ring-opening polymerization of the episulfide group can further increase the high refractive index of the cured product.

Meanwhile, in chemical formula 1, R₁And R₂May each independently be hydrogen or methyl, but is not limited thereto.

Furthermore, R₃And R₄May each independently be a single bond, methylene, ethylene, propylene, isopropylene, butylene, or isobutylene, but is not limited thereto.

Further, a and b may each independently be 0 or 1.

In chemical formula 1, a denotes the number of carbon atoms of the alkylene group contained in the thioether repeating unit. If a is too large, the length of the carbon chain in the molecule becomes longer and the glass transition temperature of the cured product during curing is lowered, which may cause a problem of lowering the heat resistance of the cured product, and in addition, the relative sulfur content becomes lower, which may cause a problem of lowering the refractive index of the cured product.

In chemical formula 1, b is the number of repetitions of a thioether repeating unit in which alkylene groups are connected through a sulfur (S) atom. If b is too large, the length of the carbon chain in the molecule becomes longer, and the glass transition temperature of the cured product decreases during curing, which may cause a problem that the heat resistance of the cured product decreases.

In addition, the compound represented by chemical formula 1 may be used alone or in a combination of two or more thereof.

The episulfide compound may include, for example, 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, 1, 4-bis (β -epithiopropylthio) butane, and the like, but the present disclosure is not necessarily limited thereto.

The content of the episulfide compound may be 50 to 99 wt%, 60 to 95 wt%, or 70 to 90 wt% based on 100 wt% of the entire curable composition. If the content of the episulfide compound is too large, there is a problem in that: the content of other components such as the cured product is relatively low, and uncured by-products are generated, which lowers the glass transition temperature of the optical material as the cured product and increases the Yellowness Index (YI). On the other hand, if the content of the episulfide compound is too small, the content of other components such as a curing agent is relatively high, and these are not sufficiently dissolved in the curable composition, or uncured by-products are generated, which causes problems that the glass transition temperature of the optical material of the cured product is lowered and the Yellowness Index (YI) is increased.

The aromatic ring compound containing two or more hydroxyl groups included in the curable composition may be a compound represented by the following chemical formula 2 or 3.

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

R₅and R₆Each independently is deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 3 to 40 carbon atomsA cycloalkyl group, an alkenyl group having 1 to 40 carbon atoms, an aryl group having 6 to 60 carbon atoms, or a heteroaryl group having 1 to 40 carbon atoms containing at least one of O, N, Si and S,

c and d are each independently an integer of 1 to 7,

e and f are each independently an integer from 0 to 6,

c + e is 7 or less, d + f is 7 or less,

[ chemical formula 3]

In the chemical formula 3, the first and second,

Ar₁and Ar₂Each independently an aryl group having 6 to 60 carbon atoms in which one or more hydroxyl groups are substituted,

R₇and R₈Each independently is deuterium, halogen, cyano, nitrile, nitro, amino, alkyl having 1 to 40 carbon atoms, alkoxy having 1 to 40 carbon atoms, cycloalkyl having 3 to 40 carbon atoms, alkenyl having 1 to 40 carbon atoms, aryl having 6 to 60 carbon atoms, or 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.

Specifically, the aromatic ring compound containing two or more hydroxyl groups represented by chemical formula 2 has a skeleton in which two naphthalenes are linked, and one or more hydroxyl groups may be linked to each naphthalene.

On the other hand, the aromatic ring compound containing two or more hydroxyl groups represented by chemical formula 3 shows two aryl substitution forms in which one or more hydroxyl groups are substituted at the 9-position of fluorene.

In the aromatic ring compound containing two or more hydroxyl groups represented by chemical formula 2 or 3, in a curing reaction with the episulfide compound, two or more hydroxyl groups undergo a ring-opening polymerization reaction with the episulfide compound to undergo crosslinking. Since the ring-opening polymerization reaction occurs at a reaction rate (e.g., 1/1000) lower than that of a thiol compound generally used as a curing agent, the curing reaction rate can be controlled. Further, in the aromatic ring compound having two or more hydroxyl groups, the aromatic ring causes the ring-opening polymerization reaction at a reaction rate lower than that of the aliphatic hydroxyl group (for example, 1/2), and the curing reaction rate can be controlled. Therefore, the rapid curing reaction can be prevented from occurring even after the mixing of the curable composition, so that the curing reaction is controlled so as not to proceed for more than 7 days under long-term storage (for example, temperature condition of 0 ℃), and the streaking phenomenon caused by the rapid curing can be prevented.

Further, the aromatic ring compound containing two or more hydroxyl groups can achieve a high refractive index of the cured product by a conjugated system of aromatic functional groups, and due to such aromatic functional groups, even if the content of sulfur atoms is reduced due to the absence of a thiol compound, which is generally used as a curing agent, in the curing composition, the decrease in refractive index can be minimized, and further, the glass transition temperature of the cured product can be increased to 80 ℃ or more, thus improving mechanical characteristics.

Meanwhile, in chemical formula 2, R₇And R₈May each independently be deuterium, halogen, cyano, nitrile, nitro, amino, methyl or ethyl, but is not limited thereto.

Further, f and g may each independently be 1 or 2.

Further, h and i may each independently be 0 or 1.

Further, in chemical formula 3, Ar₁And Ar₂May be each independently phenyl or naphthyl substituted with 1 or 2 hydroxyl groups, but is not limited thereto.

Furthermore, R₉And R₁₀May each independently be deuterium, halogen, cyano, nitrile, nitro, amino, methyl or ethyl, but is not limited thereto.

Further, m and n may each independently be 0 or 1.

In addition, the compounds represented by chemical formula 2 or 3 may be used alone or in a combination of two or more.

The aromatic ring compound having two or more hydroxyl groups may include, for example, at least one selected from the following compounds.

The aromatic ring compound containing two or more hydroxyl groups may be contained in an amount of 0.1 to 30 wt%, 0.5 to 25 wt%, or 1 to 15 wt%, based on 100 wt% of the entire curable composition. If the content of the aromatic ring compound having two or more hydroxyl groups is too large, it may not be sufficiently dissolved or precipitated in the curable composition, and thus, it is difficult to form a cured product, or even if a cured product is formed, there is a problem that optical characteristics and mechanical characteristics are deteriorated. On the other hand, if the content of the aromatic ring compound having two or more hydroxyl groups is too small, uncured by-products and the like are generated due to a relative increase in the content of other components such as the episulfide compound, which causes problems that the glass transition temperature of the optical material as a cured product is lowered and the Yellowness Index (YI) is increased.

The curable composition according to an embodiment may further include a catalyst.

The catalyst is not particularly limited as long as it is used for accelerating the curing reaction of the curable composition. Examples thereof include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole and the like; amine compounds such as dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzylamine, 4-methyl-N, N-dimethylbenzylamine, N-dicyclohexylmethylamine, and the like; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds, such as triphenylphosphine. Further, examples of commercially available products include 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ manufactured by Shikoku Kasei Kogyo (all are product names of imidazole-based compounds); U-CAT3503N, UCAT3502T (all product names of blocked isocyanate compounds of dimethylamine) manufactured by San Apro; DBU, DBN, U-CATSA102, U-CAT5002 (all bicyclic amidine compounds and salts thereof), and the like.

The catalyst may be present in an amount of 0.001 wt% to 10 wt%, 0.01 wt% to 5 wt%, or 0.1 wt% to 1 wt%, based on 100 wt% of the total curable composition. If the content of the catalyst is too large, the curing reaction proceeds rapidly, there is a problem in handling the curable composition due to overheating, it is difficult to store for a long period of time, and a streaking phenomenon may occur. On the other hand, if the content of the catalyst is too small, optical and mechanical characteristics may be deteriorated due to non-curing.

Further, the curable composition may contain, in addition to the above, other additives for imparting specific functions to the display substrate in the art to which the present disclosure pertains, such as ultraviolet absorbers, bluing agents, and pigments.

Further, the curable composition can be stored for a long time, and a streaking phenomenon caused by rapid curing can be suppressed. Specifically, the curable composition has a viscosity of 4000cP or less, 3000cP or less, 2500cP or less, 2000cP or less, 1000cP or less, 500cP or less, 300cP or less, or 100cP to 200cP measured at room temperature (25 ℃) after being held at a temperature of-5 ℃ to 0 ℃ for 12 hours.

According to another embodiment of the present invention, there is provided an optical material comprising a cured product of an episulfide compound represented by chemical formula 1 and an aromatic ring compound containing two or more hydroxyl groups represented by chemical formula 2 or 3, wherein the episulfide compound and the aromatic ring compound containing two or more hydroxyl groups are contained in a weight ratio of 7:3 to 9: 1.

The weight ratio of the episulfide compound and the aromatic ring compound having two or more hydroxyl groups contained in the optical material may be 7:3 to 9:1, 7.5:2.5 to 9:1, or 8:2 to 9: 1. If the weight ratio of the episulfide compound and the aromatic ring compound having two or more hydroxyl groups is less than 7:3, the aromatic ring compound having two or more hydroxyl groups in the curable composition may not be sufficiently dissolved or precipitated in the curable composition, and thus, the optical characteristics and mechanical characteristics of the optical material as a cured product are deteriorated. On the other hand, if the weight ratio exceeds 9:1, uncured by-products and the like are generated due to a relative increase in the content of other components such as the episulfide compound, which causes problems in that the glass transition temperature of the optical material as a cured product is lowered and the Yellowness Index (YI) is increased.

Further, the episulfide compound and the aromatic ring compound containing two or more hydroxyl groups, additives and the like contained in the optical material are replaced with those described in the above-mentioned curable composition.

Such optical materials may be produced by a process of curing the above curable composition. Specifically, the above-mentioned curable composition or a uniform composition containing various additives in the curable composition is prepared, and the composition is injected into a mold frame made by combining a mold made of a component such as glass, metal, or polymer resin with a resin shim, and then heated and cured. At this time, in order to facilitate removal of the finally prepared resin after molding, the mold may be subjected to a mold release treatment in advance, or a mold release agent may be further added to the above-mentioned composition for use.

The temperature of the curing reaction may vary depending on the type and amount of the compound used. Typically, curing can be performed at about 50 ℃ to about 120 ℃, or about 60 ℃ to about 100 ℃, and the curing time can be about 0.1 hour to about 72 hours, or about 0.5 hour to about 24 hours.

The curing reaction can be carried out by a combination of a step of maintaining the above-mentioned predetermined polymerization temperature for a certain period of time, a step of raising the temperature, a step of lowering the temperature, and the like. After the reaction is completed, the post-treatment may be performed at a temperature of about 50 ℃ to about 150 ℃, or about 80 ℃ to about 120 ℃ for about 10 minutes to about 3 hours, thereby preventing deformation.

The optical material released after polymerization may have various functions through processes such as dyeing, coating, and the like.

The refractive index of the optical material according to another embodiment may be 1.65 or more, 1.650 to 1.800, 1.700 to 1.800, or 1.700 to 1.750.

In addition, the optical material may have a glass transition temperature of 80 ℃ or more, 80 ℃ to 150 ℃, or 85 ℃ to 130 ℃, and may have a very high glass transition temperature.

Further, the optical material may have a very high transmittance, specifically, a transmittance value of 80% or more, 80% to 99%, or 85% to 90%, measured according to JIS K7361 when the thickness is 1mm, and

further, the optical material may have a very low haze, specifically, a haze value measured according to JIS K7136 of 1% or less, 0.01% to 1%, or 0.01% to 0.5% when the thickness is 1 mm.

Further, the optical material may have a Yellowness Index (YI), specifically, a yellowness index measured according to ASTM E313-1973 of 0.1 to 10, 0.5 to 8, 1 to 7, or 1 to 5, which exhibits a low yellowness index.

The optical material according to another embodiment may be included in a wearable device, and in particular, it may be used for a lens of a wearable device instead of glass or tempered glass.

That is, the optical material has high refractive characteristics comparable to glass and is also lighter than glass or tempered glass, and has excellent optical characteristics as described above in addition to mechanical characteristics such as strength and hardness, so that it can be used as a lens of a wearable device (e.g., an augmented reality device or a virtual reality device).

In particular, since the optical material has a high glass transition temperature of 80 ℃ or more, in a wearable device in which a high temperature is generated due to continuous video transmission and output, variation in physical properties is minimized, and the optical material can be stably used.

Advantageous effects

According to the present disclosure, a curable composition that can be stored for a long time and can prevent a streaking phenomenon caused by rapid curing can be provided, and an optical material including a cured product of the curable composition, which is not only lighter than glass or tempered glass used for conventional lenses, can realize various colors while having excellent strength and hardness, and can realize a high glass transition temperature while realizing a high refractive index, can be provided.

Detailed Description

Hereinafter, the action and effect of the present invention will be described in more detail by specific examples of the present invention. However, these examples are for illustrative purposes only, and the scope of the present invention is not to be determined thereby.

Example 1

90g of the following 70A as an episulfide compound and 10g of the following A1 as an aromatic ring compound having two or more hydroxyl groups were vigorously mixed at 20 ℃ for 1 hour, and then the mixture was filtered using a glass filter having a pore size of 1 μm, and then filtered again using a PVDF filter having a pore size of 0.45 μm. Then, 1g N, N-dicyclohexylmethylamine was added as a catalyst and mixed for 5 minutes to prepare a curable composition.

A 1mm thick glass slide was placed on both sides of an LCD glass having a width and length dimension of 10cm, and about 5g of the above mixed solution was applied to the center of the LCD glass, and then covered with another LCD glass to prepare a mold. It is placed in an oven and the curing reaction is carried out at about 60 c for about 10 hours and at about 90 c for about 4 hours. After removal from the oven, the LCD glass was removed to obtain flat plastic specimens (optical materials). The thickness of the plastic specimen was about 1mm, and the thickness was measured using a Mitutoyo thickness gauge (model: ID-C112 XBS).

Examples 2 to 7 and comparative examples 1 to 3

A curable composition and a plastic test piece (optical material) as a cured product thereof were prepared in the same manner as in example 1 except that an episulfide compound and an aromatic ring compound having two or more hydroxyl groups were used in the amounts of the compounds shown in the following table 1. Meanwhile, in the case of comparative examples 1 to 3, the following 70A and/or 70B were used as thiol compounds in the amounts shown in table 2 below.

[ Table 1]

(unit: g)	70A	74A	70B	74B	A1	A2	A3	A4	A5
										Example 1	90	-	-	-	10	-	-	-	-
Example 2	90	-	-	-	-	10	-	-	-
										Example 3	90	-	-	-	-	-	10	-	-
Example 4	90	-	-	-	-	-	-	10	-
										Example 5	90	-	-	-	-	-	-	-	10
Example 6	90	-	-	-	8	-	-	-	2
										Example 7	45	45	-	-	8	-	-	-	2
Comparative example 1	90	-	10	-	-	-	-	-	-
										Comparative example 2	-	90	-	10	-	-	-	-	-
Comparative example 3	45	45	10	-	-	-	-	-	-
										Comparative example 4	93	-	-	-	7	-	-	-	-
Comparative example 5	-	95	-	-	-	5	-	-	-
										Comparative example 6	67	-	-	-	33	-	-	-	-
Comparative example 7	-	65	-	-	-	35	-	-	-

Evaluation of physical Properties

1. Evaluation of optical characteristics (transmittance, haze and yellowness index)

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

2. Measurement of sulfur atom content

The content of sulfur atoms in the sample was measured using an elemental analysis method, and the results are shown in table 2 below.

3. Measurement of refractive index

For the test sample, a spectroscopic ellipsometer manufactured by Ellipso Technology was used to measure a refractive index value at a wavelength of 532nm, and the results are shown in table 2 below.

4. Measurement of glass transition temperature (Tg)

Using a Differential Scanning Calorimeter (DSC) DSC-2500(TA Instrument), the sample was heated-cooled-heated at 10 ℃/min in a temperature range of 25 ℃ to 160 ℃, and in the second heating, the glass transition temperature (Tg) of the sample was measured, and the results are shown in table 2 below.

[ Table 2]

Referring to table 2, it can be seen that the test specimens comprising the cured products according to the examples of the present disclosure have very high transmittance, and relatively high refractive index and high glass transition temperature even while having low haze and yellowness index values.

On the other hand, it was determined that in the case of comparative example 1, the refractive index value was slightly lower even when a slightly larger amount of sulfur atoms was contained as compared with the examples of the present disclosure, and in the case of comparative example 2, the transmittance was slightly lower. Further, in the case of comparative examples 1 to 3, the glass transition temperature was significantly lower than that of the examples, and there were problems in that curing was performed immediately after the preparation of the composition and the viscosity was too high, so that it was difficult to prepare it into a plastic resin sample or process it into a lens.

Further, it was confirmed that in the case of the curable compositions of comparative examples 4 and 5, although a slightly larger amount of sulfur atoms was contained, the refractive index value was slightly lower and the glass transition temperature was significantly lower than that of the examples. Further, in the case of the curable compositions of comparative examples 6 and 7, the content of the aromatic ring compound having two or more hydroxyl groups as the solid curing agent is high so that it is not dissolved or precipitated in the curable composition. Due to these problems, plastic test pieces (optical materials) cannot be manufactured.